Remove LLVM 8.0.1 files.

1 files changed, 0 insertions, 12453 deletions

diff --git a/gnu/llvm/lib/Analysis/ScalarEvolution.cpp b/gnu/llvm/lib/Analysis/ScalarEvolution.cpp
deleted file mode 100644
index e5134f2eeda..00000000000
--- a/gnu/llvm/lib/Analysis/ScalarEvolution.cpp
+++ /dev/null
@@ -1,12453 +0,0 @@
-//===- ScalarEvolution.cpp - Scalar Evolution Analysis --------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file contains the implementation of the scalar evolution analysis
-// engine, which is used primarily to analyze expressions involving induction
-// variables in loops.
-//
-// There are several aspects to this library.  First is the representation of
-// scalar expressions, which are represented as subclasses of the SCEV class.
-// These classes are used to represent certain types of subexpressions that we
-// can handle. We only create one SCEV of a particular shape, so
-// pointer-comparisons for equality are legal.
-//
-// One important aspect of the SCEV objects is that they are never cyclic, even
-// if there is a cycle in the dataflow for an expression (ie, a PHI node).  If
-// the PHI node is one of the idioms that we can represent (e.g., a polynomial
-// recurrence) then we represent it directly as a recurrence node, otherwise we
-// represent it as a SCEVUnknown node.
-//
-// In addition to being able to represent expressions of various types, we also
-// have folders that are used to build the *canonical* representation for a
-// particular expression.  These folders are capable of using a variety of
-// rewrite rules to simplify the expressions.
-//
-// Once the folders are defined, we can implement the more interesting
-// higher-level code, such as the code that recognizes PHI nodes of various
-// types, computes the execution count of a loop, etc.
-//
-// TODO: We should use these routines and value representations to implement
-// dependence analysis!
-//
-//===----------------------------------------------------------------------===//
-//
-// There are several good references for the techniques used in this analysis.
-//
-//  Chains of recurrences -- a method to expedite the evaluation
-//  of closed-form functions
-//  Olaf Bachmann, Paul S. Wang, Eugene V. Zima
-//
-//  On computational properties of chains of recurrences
-//  Eugene V. Zima
-//
-//  Symbolic Evaluation of Chains of Recurrences for Loop Optimization
-//  Robert A. van Engelen
-//
-//  Efficient Symbolic Analysis for Optimizing Compilers
-//  Robert A. van Engelen
-//
-//  Using the chains of recurrences algebra for data dependence testing and
-//  induction variable substitution
-//  MS Thesis, Johnie Birch
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Analysis/ScalarEvolution.h"
-#include "llvm/ADT/APInt.h"
-#include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/DepthFirstIterator.h"
-#include "llvm/ADT/EquivalenceClasses.h"
-#include "llvm/ADT/FoldingSet.h"
-#include "llvm/ADT/None.h"
-#include "llvm/ADT/Optional.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/ScopeExit.h"
-#include "llvm/ADT/Sequence.h"
-#include "llvm/ADT/SetVector.h"
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/SmallSet.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/StringRef.h"
-#include "llvm/Analysis/AssumptionCache.h"
-#include "llvm/Analysis/ConstantFolding.h"
-#include "llvm/Analysis/InstructionSimplify.h"
-#include "llvm/Analysis/LoopInfo.h"
-#include "llvm/Analysis/ScalarEvolutionExpressions.h"
-#include "llvm/Analysis/TargetLibraryInfo.h"
-#include "llvm/Analysis/ValueTracking.h"
-#include "llvm/Config/llvm-config.h"
-#include "llvm/IR/Argument.h"
-#include "llvm/IR/BasicBlock.h"
-#include "llvm/IR/CFG.h"
-#include "llvm/IR/CallSite.h"
-#include "llvm/IR/Constant.h"
-#include "llvm/IR/ConstantRange.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/DataLayout.h"
-#include "llvm/IR/DerivedTypes.h"
-#include "llvm/IR/Dominators.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/GlobalAlias.h"
-#include "llvm/IR/GlobalValue.h"
-#include "llvm/IR/GlobalVariable.h"
-#include "llvm/IR/InstIterator.h"
-#include "llvm/IR/InstrTypes.h"
-#include "llvm/IR/Instruction.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/IntrinsicInst.h"
-#include "llvm/IR/Intrinsics.h"
-#include "llvm/IR/LLVMContext.h"
-#include "llvm/IR/Metadata.h"
-#include "llvm/IR/Operator.h"
-#include "llvm/IR/PatternMatch.h"
-#include "llvm/IR/Type.h"
-#include "llvm/IR/Use.h"
-#include "llvm/IR/User.h"
-#include "llvm/IR/Value.h"
-#include "llvm/IR/Verifier.h"
-#include "llvm/Pass.h"
-#include "llvm/Support/Casting.h"
-#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Compiler.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/KnownBits.h"
-#include "llvm/Support/SaveAndRestore.h"
-#include "llvm/Support/raw_ostream.h"
-#include <algorithm>
-#include <cassert>
-#include <climits>
-#include <cstddef>
-#include <cstdint>
-#include <cstdlib>
-#include <map>
-#include <memory>
-#include <tuple>
-#include <utility>
-#include <vector>
-
-using namespace llvm;
-
-#define DEBUG_TYPE "scalar-evolution"
-
-STATISTIC(NumArrayLenItCounts,
-          "Number of trip counts computed with array length");
-STATISTIC(NumTripCountsComputed,
-          "Number of loops with predictable loop counts");
-STATISTIC(NumTripCountsNotComputed,
-          "Number of loops without predictable loop counts");
-STATISTIC(NumBruteForceTripCountsComputed,
-          "Number of loops with trip counts computed by force");
-
-static cl::opt<unsigned>
-MaxBruteForceIterations("scalar-evolution-max-iterations", cl::ReallyHidden,
-                        cl::desc("Maximum number of iterations SCEV will "
-                                 "symbolically execute a constant "
-                                 "derived loop"),
-                        cl::init(100));
-
-// FIXME: Enable this with EXPENSIVE_CHECKS when the test suite is clean.
-static cl::opt<bool> VerifySCEV(
-    "verify-scev", cl::Hidden,
-    cl::desc("Verify ScalarEvolution's backedge taken counts (slow)"));
-static cl::opt<bool>
-    VerifySCEVMap("verify-scev-maps", cl::Hidden,
-                  cl::desc("Verify no dangling value in ScalarEvolution's "
-                           "ExprValueMap (slow)"));
-
-static cl::opt<bool> VerifyIR(
-    "scev-verify-ir", cl::Hidden,
-    cl::desc("Verify IR correctness when making sensitive SCEV queries (slow)"),
-    cl::init(false));
-
-static cl::opt<unsigned> MulOpsInlineThreshold(
-    "scev-mulops-inline-threshold", cl::Hidden,
-    cl::desc("Threshold for inlining multiplication operands into a SCEV"),
-    cl::init(32));
-
-static cl::opt<unsigned> AddOpsInlineThreshold(
-    "scev-addops-inline-threshold", cl::Hidden,
-    cl::desc("Threshold for inlining addition operands into a SCEV"),
-    cl::init(500));
-
-static cl::opt<unsigned> MaxSCEVCompareDepth(
-    "scalar-evolution-max-scev-compare-depth", cl::Hidden,
-    cl::desc("Maximum depth of recursive SCEV complexity comparisons"),
-    cl::init(32));
-
-static cl::opt<unsigned> MaxSCEVOperationsImplicationDepth(
-    "scalar-evolution-max-scev-operations-implication-depth", cl::Hidden,
-    cl::desc("Maximum depth of recursive SCEV operations implication analysis"),
-    cl::init(2));
-
-static cl::opt<unsigned> MaxValueCompareDepth(
-    "scalar-evolution-max-value-compare-depth", cl::Hidden,
-    cl::desc("Maximum depth of recursive value complexity comparisons"),
-    cl::init(2));
-
-static cl::opt<unsigned>
-    MaxArithDepth("scalar-evolution-max-arith-depth", cl::Hidden,
-                  cl::desc("Maximum depth of recursive arithmetics"),
-                  cl::init(32));
-
-static cl::opt<unsigned> MaxConstantEvolvingDepth(
-    "scalar-evolution-max-constant-evolving-depth", cl::Hidden,
-    cl::desc("Maximum depth of recursive constant evolving"), cl::init(32));
-
-static cl::opt<unsigned>
-    MaxExtDepth("scalar-evolution-max-ext-depth", cl::Hidden,
-                cl::desc("Maximum depth of recursive SExt/ZExt"),
-                cl::init(8));
-
-static cl::opt<unsigned>
-    MaxAddRecSize("scalar-evolution-max-add-rec-size", cl::Hidden,
-                  cl::desc("Max coefficients in AddRec during evolving"),
-                  cl::init(8));
-
-//===----------------------------------------------------------------------===//
-//                           SCEV class definitions
-//===----------------------------------------------------------------------===//
-
-//===----------------------------------------------------------------------===//
-// Implementation of the SCEV class.
-//
-
-#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
-LLVM_DUMP_METHOD void SCEV::dump() const {
-  print(dbgs());
-  dbgs() << '\n';
-}
-#endif
-
-void SCEV::print(raw_ostream &OS) const {
-  switch (static_cast<SCEVTypes>(getSCEVType())) {
-  case scConstant:
-    cast<SCEVConstant>(this)->getValue()->printAsOperand(OS, false);
-    return;
-  case scTruncate: {
-    const SCEVTruncateExpr *Trunc = cast<SCEVTruncateExpr>(this);
-    const SCEV *Op = Trunc->getOperand();
-    OS << "(trunc " << *Op->getType() << " " << *Op << " to "
-       << *Trunc->getType() << ")";
-    return;
-  }
-  case scZeroExtend: {
-    const SCEVZeroExtendExpr *ZExt = cast<SCEVZeroExtendExpr>(this);
-    const SCEV *Op = ZExt->getOperand();
-    OS << "(zext " << *Op->getType() << " " << *Op << " to "
-       << *ZExt->getType() << ")";
-    return;
-  }
-  case scSignExtend: {
-    const SCEVSignExtendExpr *SExt = cast<SCEVSignExtendExpr>(this);
-    const SCEV *Op = SExt->getOperand();
-    OS << "(sext " << *Op->getType() << " " << *Op << " to "
-       << *SExt->getType() << ")";
-    return;
-  }
-  case scAddRecExpr: {
-    const SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(this);
-    OS << "{" << *AR->getOperand(0);
-    for (unsigned i = 1, e = AR->getNumOperands(); i != e; ++i)
-      OS << ",+," << *AR->getOperand(i);
-    OS << "}<";
-    if (AR->hasNoUnsignedWrap())
-      OS << "nuw><";
-    if (AR->hasNoSignedWrap())
-      OS << "nsw><";
-    if (AR->hasNoSelfWrap() &&
-        !AR->getNoWrapFlags((NoWrapFlags)(FlagNUW | FlagNSW)))
-      OS << "nw><";
-    AR->getLoop()->getHeader()->printAsOperand(OS, /*PrintType=*/false);
-    OS << ">";
-    return;
-  }
-  case scAddExpr:
-  case scMulExpr:
-  case scUMaxExpr:
-  case scSMaxExpr: {
-    const SCEVNAryExpr *NAry = cast<SCEVNAryExpr>(this);
-    const char *OpStr = nullptr;
-    switch (NAry->getSCEVType()) {
-    case scAddExpr: OpStr = " + "; break;
-    case scMulExpr: OpStr = " * "; break;
-    case scUMaxExpr: OpStr = " umax "; break;
-    case scSMaxExpr: OpStr = " smax "; break;
-    }
-    OS << "(";
-    for (SCEVNAryExpr::op_iterator I = NAry->op_begin(), E = NAry->op_end();
-         I != E; ++I) {
-      OS << **I;
-      if (std::next(I) != E)
-        OS << OpStr;
-    }
-    OS << ")";
-    switch (NAry->getSCEVType()) {
-    case scAddExpr:
-    case scMulExpr:
-      if (NAry->hasNoUnsignedWrap())
-        OS << "<nuw>";
-      if (NAry->hasNoSignedWrap())
-        OS << "<nsw>";
-    }
-    return;
-  }
-  case scUDivExpr: {
-    const SCEVUDivExpr *UDiv = cast<SCEVUDivExpr>(this);
-    OS << "(" << *UDiv->getLHS() << " /u " << *UDiv->getRHS() << ")";
-    return;
-  }
-  case scUnknown: {
-    const SCEVUnknown *U = cast<SCEVUnknown>(this);
-    Type *AllocTy;
-    if (U->isSizeOf(AllocTy)) {
-      OS << "sizeof(" << *AllocTy << ")";
-      return;
-    }
-    if (U->isAlignOf(AllocTy)) {
-      OS << "alignof(" << *AllocTy << ")";
-      return;
-    }
-
-    Type *CTy;
-    Constant *FieldNo;
-    if (U->isOffsetOf(CTy, FieldNo)) {
-      OS << "offsetof(" << *CTy << ", ";
-      FieldNo->printAsOperand(OS, false);
-      OS << ")";
-      return;
-    }
-
-    // Otherwise just print it normally.
-    U->getValue()->printAsOperand(OS, false);
-    return;
-  }
-  case scCouldNotCompute:
-    OS << "***COULDNOTCOMPUTE***";
-    return;
-  }
-  llvm_unreachable("Unknown SCEV kind!");
-}
-
-Type *SCEV::getType() const {
-  switch (static_cast<SCEVTypes>(getSCEVType())) {
-  case scConstant:
-    return cast<SCEVConstant>(this)->getType();
-  case scTruncate:
-  case scZeroExtend:
-  case scSignExtend:
-    return cast<SCEVCastExpr>(this)->getType();
-  case scAddRecExpr:
-  case scMulExpr:
-  case scUMaxExpr:
-  case scSMaxExpr:
-    return cast<SCEVNAryExpr>(this)->getType();
-  case scAddExpr:
-    return cast<SCEVAddExpr>(this)->getType();
-  case scUDivExpr:
-    return cast<SCEVUDivExpr>(this)->getType();
-  case scUnknown:
-    return cast<SCEVUnknown>(this)->getType();
-  case scCouldNotCompute:
-    llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
-  }
-  llvm_unreachable("Unknown SCEV kind!");
-}
-
-bool SCEV::isZero() const {
-  if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(this))
-    return SC->getValue()->isZero();
-  return false;
-}
-
-bool SCEV::isOne() const {
-  if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(this))
-    return SC->getValue()->isOne();
-  return false;
-}
-
-bool SCEV::isAllOnesValue() const {
-  if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(this))
-    return SC->getValue()->isMinusOne();
-  return false;
-}
-
-bool SCEV::isNonConstantNegative() const {
-  const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(this);
-  if (!Mul) return false;
-
-  // If there is a constant factor, it will be first.
-  const SCEVConstant *SC = dyn_cast<SCEVConstant>(Mul->getOperand(0));
-  if (!SC) return false;
-
-  // Return true if the value is negative, this matches things like (-42 * V).
-  return SC->getAPInt().isNegative();
-}
-
-SCEVCouldNotCompute::SCEVCouldNotCompute() :
-  SCEV(FoldingSetNodeIDRef(), scCouldNotCompute) {}
-
-bool SCEVCouldNotCompute::classof(const SCEV *S) {
-  return S->getSCEVType() == scCouldNotCompute;
-}
-
-const SCEV *ScalarEvolution::getConstant(ConstantInt *V) {
-  FoldingSetNodeID ID;
-  ID.AddInteger(scConstant);
-  ID.AddPointer(V);
-  void *IP = nullptr;
-  if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
-  SCEV *S = new (SCEVAllocator) SCEVConstant(ID.Intern(SCEVAllocator), V);
-  UniqueSCEVs.InsertNode(S, IP);
-  return S;
-}
-
-const SCEV *ScalarEvolution::getConstant(const APInt &Val) {
-  return getConstant(ConstantInt::get(getContext(), Val));
-}
-
-const SCEV *
-ScalarEvolution::getConstant(Type *Ty, uint64_t V, bool isSigned) {
-  IntegerType *ITy = cast<IntegerType>(getEffectiveSCEVType(Ty));
-  return getConstant(ConstantInt::get(ITy, V, isSigned));
-}
-
-SCEVCastExpr::SCEVCastExpr(const FoldingSetNodeIDRef ID,
-                           unsigned SCEVTy, const SCEV *op, Type *ty)
-  : SCEV(ID, SCEVTy), Op(op), Ty(ty) {}
-
-SCEVTruncateExpr::SCEVTruncateExpr(const FoldingSetNodeIDRef ID,
-                                   const SCEV *op, Type *ty)
-  : SCEVCastExpr(ID, scTruncate, op, ty) {
-  assert(Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
-         "Cannot truncate non-integer value!");
-}
-
-SCEVZeroExtendExpr::SCEVZeroExtendExpr(const FoldingSetNodeIDRef ID,
-                                       const SCEV *op, Type *ty)
-  : SCEVCastExpr(ID, scZeroExtend, op, ty) {
-  assert(Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
-         "Cannot zero extend non-integer value!");
-}
-
-SCEVSignExtendExpr::SCEVSignExtendExpr(const FoldingSetNodeIDRef ID,
-                                       const SCEV *op, Type *ty)
-  : SCEVCastExpr(ID, scSignExtend, op, ty) {
-  assert(Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
-         "Cannot sign extend non-integer value!");
-}
-
-void SCEVUnknown::deleted() {
-  // Clear this SCEVUnknown from various maps.
-  SE->forgetMemoizedResults(this);
-
-  // Remove this SCEVUnknown from the uniquing map.
-  SE->UniqueSCEVs.RemoveNode(this);
-
-  // Release the value.
-  setValPtr(nullptr);
-}
-
-void SCEVUnknown::allUsesReplacedWith(Value *New) {
-  // Remove this SCEVUnknown from the uniquing map.
-  SE->UniqueSCEVs.RemoveNode(this);
-
-  // Update this SCEVUnknown to point to the new value. This is needed
-  // because there may still be outstanding SCEVs which still point to
-  // this SCEVUnknown.
-  setValPtr(New);
-}
-
-bool SCEVUnknown::isSizeOf(Type *&AllocTy) const {
-  if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(getValue()))
-    if (VCE->getOpcode() == Instruction::PtrToInt)
-      if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0)))
-        if (CE->getOpcode() == Instruction::GetElementPtr &&
-            CE->getOperand(0)->isNullValue() &&
-            CE->getNumOperands() == 2)
-          if (ConstantInt *CI = dyn_cast<ConstantInt>(CE->getOperand(1)))
-            if (CI->isOne()) {
-              AllocTy = cast<PointerType>(CE->getOperand(0)->getType())
-                                 ->getElementType();
-              return true;
-            }
-
-  return false;
-}
-
-bool SCEVUnknown::isAlignOf(Type *&AllocTy) const {
-  if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(getValue()))
-    if (VCE->getOpcode() == Instruction::PtrToInt)
-      if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0)))
-        if (CE->getOpcode() == Instruction::GetElementPtr &&
-            CE->getOperand(0)->isNullValue()) {
-          Type *Ty =
-            cast<PointerType>(CE->getOperand(0)->getType())->getElementType();
-          if (StructType *STy = dyn_cast<StructType>(Ty))
-            if (!STy->isPacked() &&
-                CE->getNumOperands() == 3 &&
-                CE->getOperand(1)->isNullValue()) {
-              if (ConstantInt *CI = dyn_cast<ConstantInt>(CE->getOperand(2)))
-                if (CI->isOne() &&
-                    STy->getNumElements() == 2 &&
-                    STy->getElementType(0)->isIntegerTy(1)) {
-                  AllocTy = STy->getElementType(1);
-                  return true;
-                }
-            }
-        }
-
-  return false;
-}
-
-bool SCEVUnknown::isOffsetOf(Type *&CTy, Constant *&FieldNo) const {
-  if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(getValue()))
-    if (VCE->getOpcode() == Instruction::PtrToInt)
-      if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0)))
-        if (CE->getOpcode() == Instruction::GetElementPtr &&
-            CE->getNumOperands() == 3 &&
-            CE->getOperand(0)->isNullValue() &&
-            CE->getOperand(1)->isNullValue()) {
-          Type *Ty =
-            cast<PointerType>(CE->getOperand(0)->getType())->getElementType();
-          // Ignore vector types here so that ScalarEvolutionExpander doesn't
-          // emit getelementptrs that index into vectors.
-          if (Ty->isStructTy() || Ty->isArrayTy()) {
-            CTy = Ty;
-            FieldNo = CE->getOperand(2);
-            return true;
-          }
-        }
-
-  return false;
-}
-
-//===----------------------------------------------------------------------===//
-//                               SCEV Utilities
-//===----------------------------------------------------------------------===//
-
-/// Compare the two values \p LV and \p RV in terms of their "complexity" where
-/// "complexity" is a partial (and somewhat ad-hoc) relation used to order
-/// operands in SCEV expressions.  \p EqCache is a set of pairs of values that
-/// have been previously deemed to be "equally complex" by this routine.  It is
-/// intended to avoid exponential time complexity in cases like:
-///
-///   %a = f(%x, %y)
-///   %b = f(%a, %a)
-///   %c = f(%b, %b)
-///
-///   %d = f(%x, %y)
-///   %e = f(%d, %d)
-///   %f = f(%e, %e)
-///
-///   CompareValueComplexity(%f, %c)
-///
-/// Since we do not continue running this routine on expression trees once we
-/// have seen unequal values, there is no need to track them in the cache.
-static int
-CompareValueComplexity(EquivalenceClasses<const Value *> &EqCacheValue,
-                       const LoopInfo *const LI, Value *LV, Value *RV,
-                       unsigned Depth) {
-  if (Depth > MaxValueCompareDepth || EqCacheValue.isEquivalent(LV, RV))
-    return 0;
-
-  // Order pointer values after integer values. This helps SCEVExpander form
-  // GEPs.
-  bool LIsPointer = LV->getType()->isPointerTy(),
-       RIsPointer = RV->getType()->isPointerTy();
-  if (LIsPointer != RIsPointer)
-    return (int)LIsPointer - (int)RIsPointer;
-
-  // Compare getValueID values.
-  unsigned LID = LV->getValueID(), RID = RV->getValueID();
-  if (LID != RID)
-    return (int)LID - (int)RID;
-
-  // Sort arguments by their position.
-  if (const auto *LA = dyn_cast<Argument>(LV)) {
-    const auto *RA = cast<Argument>(RV);
-    unsigned LArgNo = LA->getArgNo(), RArgNo = RA->getArgNo();
-    return (int)LArgNo - (int)RArgNo;
-  }
-
-  if (const auto *LGV = dyn_cast<GlobalValue>(LV)) {
-    const auto *RGV = cast<GlobalValue>(RV);
-
-    const auto IsGVNameSemantic = [&](const GlobalValue *GV) {
-      auto LT = GV->getLinkage();
-      return !(GlobalValue::isPrivateLinkage(LT) ||
-               GlobalValue::isInternalLinkage(LT));
-    };
-
-    // Use the names to distinguish the two values, but only if the
-    // names are semantically important.
-    if (IsGVNameSemantic(LGV) && IsGVNameSemantic(RGV))
-      return LGV->getName().compare(RGV->getName());
-  }
-
-  // For instructions, compare their loop depth, and their operand count.  This
-  // is pretty loose.
-  if (const auto *LInst = dyn_cast<Instruction>(LV)) {
-    const auto *RInst = cast<Instruction>(RV);
-
-    // Compare loop depths.
-    const BasicBlock *LParent = LInst->getParent(),
-                     *RParent = RInst->getParent();
-    if (LParent != RParent) {
-      unsigned LDepth = LI->getLoopDepth(LParent),
-               RDepth = LI->getLoopDepth(RParent);
-      if (LDepth != RDepth)
-        return (int)LDepth - (int)RDepth;
-    }
-
-    // Compare the number of operands.
-    unsigned LNumOps = LInst->getNumOperands(),
-             RNumOps = RInst->getNumOperands();
-    if (LNumOps != RNumOps)
-      return (int)LNumOps - (int)RNumOps;
-
-    for (unsigned Idx : seq(0u, LNumOps)) {
-      int Result =
-          CompareValueComplexity(EqCacheValue, LI, LInst->getOperand(Idx),
-                                 RInst->getOperand(Idx), Depth + 1);
-      if (Result != 0)
-        return Result;
-    }
-  }
-
-  EqCacheValue.unionSets(LV, RV);
-  return 0;
-}
-
-// Return negative, zero, or positive, if LHS is less than, equal to, or greater
-// than RHS, respectively. A three-way result allows recursive comparisons to be
-// more efficient.
-static int CompareSCEVComplexity(
-    EquivalenceClasses<const SCEV *> &EqCacheSCEV,
-    EquivalenceClasses<const Value *> &EqCacheValue,
-    const LoopInfo *const LI, const SCEV *LHS, const SCEV *RHS,
-    DominatorTree &DT, unsigned Depth = 0) {
-  // Fast-path: SCEVs are uniqued so we can do a quick equality check.
-  if (LHS == RHS)
-    return 0;
-
-  // Primarily, sort the SCEVs by their getSCEVType().
-  unsigned LType = LHS->getSCEVType(), RType = RHS->getSCEVType();
-  if (LType != RType)
-    return (int)LType - (int)RType;
-
-  if (Depth > MaxSCEVCompareDepth || EqCacheSCEV.isEquivalent(LHS, RHS))
-    return 0;
-  // Aside from the getSCEVType() ordering, the particular ordering
-  // isn't very important except that it's beneficial to be consistent,
-  // so that (a + b) and (b + a) don't end up as different expressions.
-  switch (static_cast<SCEVTypes>(LType)) {
-  case scUnknown: {
-    const SCEVUnknown *LU = cast<SCEVUnknown>(LHS);
-    const SCEVUnknown *RU = cast<SCEVUnknown>(RHS);
-
-    int X = CompareValueComplexity(EqCacheValue, LI, LU->getValue(),
-                                   RU->getValue(), Depth + 1);
-    if (X == 0)
-      EqCacheSCEV.unionSets(LHS, RHS);
-    return X;
-  }
-
-  case scConstant: {
-    const SCEVConstant *LC = cast<SCEVConstant>(LHS);
-    const SCEVConstant *RC = cast<SCEVConstant>(RHS);
-
-    // Compare constant values.
-    const APInt &LA = LC->getAPInt();
-    const APInt &RA = RC->getAPInt();
-    unsigned LBitWidth = LA.getBitWidth(), RBitWidth = RA.getBitWidth();
-    if (LBitWidth != RBitWidth)
-      return (int)LBitWidth - (int)RBitWidth;
-    return LA.ult(RA) ? -1 : 1;
-  }
-
-  case scAddRecExpr: {
-    const SCEVAddRecExpr *LA = cast<SCEVAddRecExpr>(LHS);
-    const SCEVAddRecExpr *RA = cast<SCEVAddRecExpr>(RHS);
-
-    // There is always a dominance between two recs that are used by one SCEV,
-    // so we can safely sort recs by loop header dominance. We require such
-    // order in getAddExpr.
-    const Loop *LLoop = LA->getLoop(), *RLoop = RA->getLoop();
-    if (LLoop != RLoop) {
-      const BasicBlock *LHead = LLoop->getHeader(), *RHead = RLoop->getHeader();
-      assert(LHead != RHead && "Two loops share the same header?");
-      if (DT.dominates(LHead, RHead))
-        return 1;
-      else
-        assert(DT.dominates(RHead, LHead) &&
-               "No dominance between recurrences used by one SCEV?");
-      return -1;
-    }
-
-    // Addrec complexity grows with operand count.
-    unsigned LNumOps = LA->getNumOperands(), RNumOps = RA->getNumOperands();
-    if (LNumOps != RNumOps)
-      return (int)LNumOps - (int)RNumOps;
-
-    // Lexicographically compare.
-    for (unsigned i = 0; i != LNumOps; ++i) {
-      int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI,
-                                    LA->getOperand(i), RA->getOperand(i), DT,
-                                    Depth + 1);
-      if (X != 0)
-        return X;
-    }
-    EqCacheSCEV.unionSets(LHS, RHS);
-    return 0;
-  }
-
-  case scAddExpr:
-  case scMulExpr:
-  case scSMaxExpr:
-  case scUMaxExpr: {
-    const SCEVNAryExpr *LC = cast<SCEVNAryExpr>(LHS);
-    const SCEVNAryExpr *RC = cast<SCEVNAryExpr>(RHS);
-
-    // Lexicographically compare n-ary expressions.
-    unsigned LNumOps = LC->getNumOperands(), RNumOps = RC->getNumOperands();
-    if (LNumOps != RNumOps)
-      return (int)LNumOps - (int)RNumOps;
-
-    for (unsigned i = 0; i != LNumOps; ++i) {
-      int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI,
-                                    LC->getOperand(i), RC->getOperand(i), DT,
-                                    Depth + 1);
-      if (X != 0)
-        return X;
-    }
-    EqCacheSCEV.unionSets(LHS, RHS);
-    return 0;
-  }
-
-  case scUDivExpr: {
-    const SCEVUDivExpr *LC = cast<SCEVUDivExpr>(LHS);
-    const SCEVUDivExpr *RC = cast<SCEVUDivExpr>(RHS);
-
-    // Lexicographically compare udiv expressions.
-    int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, LC->getLHS(),
-                                  RC->getLHS(), DT, Depth + 1);
-    if (X != 0)
-      return X;
-    X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, LC->getRHS(),
-                              RC->getRHS(), DT, Depth + 1);
-    if (X == 0)
-      EqCacheSCEV.unionSets(LHS, RHS);
-    return X;
-  }
-
-  case scTruncate:
-  case scZeroExtend:
-  case scSignExtend: {
-    const SCEVCastExpr *LC = cast<SCEVCastExpr>(LHS);
-    const SCEVCastExpr *RC = cast<SCEVCastExpr>(RHS);
-
-    // Compare cast expressions by operand.
-    int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI,
-                                  LC->getOperand(), RC->getOperand(), DT,
-                                  Depth + 1);
-    if (X == 0)
-      EqCacheSCEV.unionSets(LHS, RHS);
-    return X;
-  }
-
-  case scCouldNotCompute:
-    llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
-  }
-  llvm_unreachable("Unknown SCEV kind!");
-}
-
-/// Given a list of SCEV objects, order them by their complexity, and group
-/// objects of the same complexity together by value.  When this routine is
-/// finished, we know that any duplicates in the vector are consecutive and that
-/// complexity is monotonically increasing.
-///
-/// Note that we go take special precautions to ensure that we get deterministic
-/// results from this routine.  In other words, we don't want the results of
-/// this to depend on where the addresses of various SCEV objects happened to
-/// land in memory.
-static void GroupByComplexity(SmallVectorImpl<const SCEV *> &Ops,
-                              LoopInfo *LI, DominatorTree &DT) {
-  if (Ops.size() < 2) return;  // Noop
-
-  EquivalenceClasses<const SCEV *> EqCacheSCEV;
-  EquivalenceClasses<const Value *> EqCacheValue;
-  if (Ops.size() == 2) {
-    // This is the common case, which also happens to be trivially simple.
-    // Special case it.
-    const SCEV *&LHS = Ops[0], *&RHS = Ops[1];
-    if (CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, RHS, LHS, DT) < 0)
-      std::swap(LHS, RHS);
-    return;
-  }
-
-  // Do the rough sort by complexity.
-  std::stable_sort(Ops.begin(), Ops.end(),
-                   [&](const SCEV *LHS, const SCEV *RHS) {
-                     return CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI,
-                                                  LHS, RHS, DT) < 0;
-                   });
-
-  // Now that we are sorted by complexity, group elements of the same
-  // complexity.  Note that this is, at worst, N^2, but the vector is likely to
-  // be extremely short in practice.  Note that we take this approach because we
-  // do not want to depend on the addresses of the objects we are grouping.
-  for (unsigned i = 0, e = Ops.size(); i != e-2; ++i) {
-    const SCEV *S = Ops[i];
-    unsigned Complexity = S->getSCEVType();
-
-    // If there are any objects of the same complexity and same value as this
-    // one, group them.
-    for (unsigned j = i+1; j != e && Ops[j]->getSCEVType() == Complexity; ++j) {
-      if (Ops[j] == S) { // Found a duplicate.
-        // Move it to immediately after i'th element.
-        std::swap(Ops[i+1], Ops[j]);
-        ++i;   // no need to rescan it.
-        if (i == e-2) return;  // Done!
-      }
-    }
-  }
-}
-
-// Returns the size of the SCEV S.
-static inline int sizeOfSCEV(const SCEV *S) {
-  struct FindSCEVSize {
-    int Size = 0;
-
-    FindSCEVSize() = default;
-
-    bool follow(const SCEV *S) {
-      ++Size;
-      // Keep looking at all operands of S.
-      return true;
-    }
-
-    bool isDone() const {
-      return false;
-    }
-  };
-
-  FindSCEVSize F;
-  SCEVTraversal<FindSCEVSize> ST(F);
-  ST.visitAll(S);
-  return F.Size;
-}
-
-namespace {
-
-struct SCEVDivision : public SCEVVisitor<SCEVDivision, void> {
-public:
-  // Computes the Quotient and Remainder of the division of Numerator by
-  // Denominator.
-  static void divide(ScalarEvolution &SE, const SCEV *Numerator,
-                     const SCEV *Denominator, const SCEV **Quotient,
-                     const SCEV **Remainder) {
-    assert(Numerator && Denominator && "Uninitialized SCEV");
-
-    SCEVDivision D(SE, Numerator, Denominator);
-
-    // Check for the trivial case here to avoid having to check for it in the
-    // rest of the code.
-    if (Numerator == Denominator) {
-      *Quotient = D.One;
-      *Remainder = D.Zero;
-      return;
-    }
-
-    if (Numerator->isZero()) {
-      *Quotient = D.Zero;
-      *Remainder = D.Zero;
-      return;
-    }
-
-    // A simple case when N/1. The quotient is N.
-    if (Denominator->isOne()) {
-      *Quotient = Numerator;
-      *Remainder = D.Zero;
-      return;
-    }
-
-    // Split the Denominator when it is a product.
-    if (const SCEVMulExpr *T = dyn_cast<SCEVMulExpr>(Denominator)) {
-      const SCEV *Q, *R;
-      *Quotient = Numerator;
-      for (const SCEV *Op : T->operands()) {
-        divide(SE, *Quotient, Op, &Q, &R);
-        *Quotient = Q;
-
-        // Bail out when the Numerator is not divisible by one of the terms of
-        // the Denominator.
-        if (!R->isZero()) {
-          *Quotient = D.Zero;
-          *Remainder = Numerator;
-          return;
-        }
-      }
-      *Remainder = D.Zero;
-      return;
-    }
-
-    D.visit(Numerator);
-    *Quotient = D.Quotient;
-    *Remainder = D.Remainder;
-  }
-
-  // Except in the trivial case described above, we do not know how to divide
-  // Expr by Denominator for the following functions with empty implementation.
-  void visitTruncateExpr(const SCEVTruncateExpr *Numerator) {}
-  void visitZeroExtendExpr(const SCEVZeroExtendExpr *Numerator) {}
-  void visitSignExtendExpr(const SCEVSignExtendExpr *Numerator) {}
-  void visitUDivExpr(const SCEVUDivExpr *Numerator) {}
-  void visitSMaxExpr(const SCEVSMaxExpr *Numerator) {}
-  void visitUMaxExpr(const SCEVUMaxExpr *Numerator) {}
-  void visitUnknown(const SCEVUnknown *Numerator) {}
-  void visitCouldNotCompute(const SCEVCouldNotCompute *Numerator) {}
-
-  void visitConstant(const SCEVConstant *Numerator) {
-    if (const SCEVConstant *D = dyn_cast<SCEVConstant>(Denominator)) {
-      APInt NumeratorVal = Numerator->getAPInt();
-      APInt DenominatorVal = D->getAPInt();
-      uint32_t NumeratorBW = NumeratorVal.getBitWidth();
-      uint32_t DenominatorBW = DenominatorVal.getBitWidth();
-
-      if (NumeratorBW > DenominatorBW)
-        DenominatorVal = DenominatorVal.sext(NumeratorBW);
-      else if (NumeratorBW < DenominatorBW)
-        NumeratorVal = NumeratorVal.sext(DenominatorBW);
-
-      APInt QuotientVal(NumeratorVal.getBitWidth(), 0);
-      APInt RemainderVal(NumeratorVal.getBitWidth(), 0);
-      APInt::sdivrem(NumeratorVal, DenominatorVal, QuotientVal, RemainderVal);
-      Quotient = SE.getConstant(QuotientVal);
-      Remainder = SE.getConstant(RemainderVal);
-      return;
-    }
-  }
-
-  void visitAddRecExpr(const SCEVAddRecExpr *Numerator) {
-    const SCEV *StartQ, *StartR, *StepQ, *StepR;
-    if (!Numerator->isAffine())
-      return cannotDivide(Numerator);
-    divide(SE, Numerator->getStart(), Denominator, &StartQ, &StartR);
-    divide(SE, Numerator->getStepRecurrence(SE), Denominator, &StepQ, &StepR);
-    // Bail out if the types do not match.
-    Type *Ty = Denominator->getType();
-    if (Ty != StartQ->getType() || Ty != StartR->getType() ||
-        Ty != StepQ->getType() || Ty != StepR->getType())
-      return cannotDivide(Numerator);
-    Quotient = SE.getAddRecExpr(StartQ, StepQ, Numerator->getLoop(),
-                                Numerator->getNoWrapFlags());
-    Remainder = SE.getAddRecExpr(StartR, StepR, Numerator->getLoop(),
-                                 Numerator->getNoWrapFlags());
-  }
-
-  void visitAddExpr(const SCEVAddExpr *Numerator) {
-    SmallVector<const SCEV *, 2> Qs, Rs;
-    Type *Ty = Denominator->getType();
-
-    for (const SCEV *Op : Numerator->operands()) {
-      const SCEV *Q, *R;
-      divide(SE, Op, Denominator, &Q, &R);
-
-      // Bail out if types do not match.
-      if (Ty != Q->getType() || Ty != R->getType())
-        return cannotDivide(Numerator);
-
-      Qs.push_back(Q);
-      Rs.push_back(R);
-    }
-
-    if (Qs.size() == 1) {
-      Quotient = Qs[0];
-      Remainder = Rs[0];
-      return;
-    }
-
-    Quotient = SE.getAddExpr(Qs);
-    Remainder = SE.getAddExpr(Rs);
-  }
-
-  void visitMulExpr(const SCEVMulExpr *Numerator) {
-    SmallVector<const SCEV *, 2> Qs;
-    Type *Ty = Denominator->getType();
-
-    bool FoundDenominatorTerm = false;
-    for (const SCEV *Op : Numerator->operands()) {
-      // Bail out if types do not match.
-      if (Ty != Op->getType())
-        return cannotDivide(Numerator);
-
-      if (FoundDenominatorTerm) {
-        Qs.push_back(Op);
-        continue;
-      }
-
-      // Check whether Denominator divides one of the product operands.
-      const SCEV *Q, *R;
-      divide(SE, Op, Denominator, &Q, &R);
-      if (!R->isZero()) {
-        Qs.push_back(Op);
-        continue;
-      }
-
-      // Bail out if types do not match.
-      if (Ty != Q->getType())
-        return cannotDivide(Numerator);
-
-      FoundDenominatorTerm = true;
-      Qs.push_back(Q);
-    }
-
-    if (FoundDenominatorTerm) {
-      Remainder = Zero;
-      if (Qs.size() == 1)
-        Quotient = Qs[0];
-      else
-        Quotient = SE.getMulExpr(Qs);
-      return;
-    }
-
-    if (!isa<SCEVUnknown>(Denominator))
-      return cannotDivide(Numerator);
-
-    // The Remainder is obtained by replacing Denominator by 0 in Numerator.
-    ValueToValueMap RewriteMap;
-    RewriteMap[cast<SCEVUnknown>(Denominator)->getValue()] =
-        cast<SCEVConstant>(Zero)->getValue();
-    Remainder = SCEVParameterRewriter::rewrite(Numerator, SE, RewriteMap, true);
-
-    if (Remainder->isZero()) {
-      // The Quotient is obtained by replacing Denominator by 1 in Numerator.
-      RewriteMap[cast<SCEVUnknown>(Denominator)->getValue()] =
-          cast<SCEVConstant>(One)->getValue();
-      Quotient =
-          SCEVParameterRewriter::rewrite(Numerator, SE, RewriteMap, true);
-      return;
-    }
-
-    // Quotient is (Numerator - Remainder) divided by Denominator.
-    const SCEV *Q, *R;
-    const SCEV *Diff = SE.getMinusSCEV(Numerator, Remainder);
-    // This SCEV does not seem to simplify: fail the division here.
-    if (sizeOfSCEV(Diff) > sizeOfSCEV(Numerator))
-      return cannotDivide(Numerator);
-    divide(SE, Diff, Denominator, &Q, &R);
-    if (R != Zero)
-      return cannotDivide(Numerator);
-    Quotient = Q;
-  }
-
-private:
-  SCEVDivision(ScalarEvolution &S, const SCEV *Numerator,
-               const SCEV *Denominator)
-      : SE(S), Denominator(Denominator) {
-    Zero = SE.getZero(Denominator->getType());
-    One = SE.getOne(Denominator->getType());
-
-    // We generally do not know how to divide Expr by Denominator. We
-    // initialize the division to a "cannot divide" state to simplify the rest
-    // of the code.
-    cannotDivide(Numerator);
-  }
-
-  // Convenience function for giving up on the division. We set the quotient to
-  // be equal to zero and the remainder to be equal to the numerator.
-  void cannotDivide(const SCEV *Numerator) {
-    Quotient = Zero;
-    Remainder = Numerator;
-  }
-
-  ScalarEvolution &SE;
-  const SCEV *Denominator, *Quotient, *Remainder, *Zero, *One;
-};
-
-} // end anonymous namespace
-
-//===----------------------------------------------------------------------===//
-//                      Simple SCEV method implementations
-//===----------------------------------------------------------------------===//
-
-/// Compute BC(It, K).  The result has width W.  Assume, K > 0.
-static const SCEV *BinomialCoefficient(const SCEV *It, unsigned K,
-                                       ScalarEvolution &SE,
-                                       Type *ResultTy) {
-  // Handle the simplest case efficiently.
-  if (K == 1)
-    return SE.getTruncateOrZeroExtend(It, ResultTy);
-
-  // We are using the following formula for BC(It, K):
-  //
-  //   BC(It, K) = (It * (It - 1) * ... * (It - K + 1)) / K!
-  //
-  // Suppose, W is the bitwidth of the return value.  We must be prepared for
-  // overflow.  Hence, we must assure that the result of our computation is
-  // equal to the accurate one modulo 2^W.  Unfortunately, division isn't
-  // safe in modular arithmetic.
-  //
-  // However, this code doesn't use exactly that formula; the formula it uses
-  // is something like the following, where T is the number of factors of 2 in
-  // K! (i.e. trailing zeros in the binary representation of K!), and ^ is
-  // exponentiation:
-  //
-  //   BC(It, K) = (It * (It - 1) * ... * (It - K + 1)) / 2^T / (K! / 2^T)
-  //
-  // This formula is trivially equivalent to the previous formula.  However,
-  // this formula can be implemented much more efficiently.  The trick is that
-  // K! / 2^T is odd, and exact division by an odd number *is* safe in modular
-  // arithmetic.  To do exact division in modular arithmetic, all we have
-  // to do is multiply by the inverse.  Therefore, this step can be done at
-  // width W.
-  //
-  // The next issue is how to safely do the division by 2^T.  The way this
-  // is done is by doing the multiplication step at a width of at least W + T
-  // bits.  This way, the bottom W+T bits of the product are accurate. Then,
-  // when we perform the division by 2^T (which is equivalent to a right shift
-  // by T), the bottom W bits are accurate.  Extra bits are okay; they'll get
-  // truncated out after the division by 2^T.
-  //
-  // In comparison to just directly using the first formula, this technique
-  // is much more efficient; using the first formula requires W * K bits,
-  // but this formula less than W + K bits. Also, the first formula requires
-  // a division step, whereas this formula only requires multiplies and shifts.
-  //
-  // It doesn't matter whether the subtraction step is done in the calculation
-  // width or the input iteration count's width; if the subtraction overflows,
-  // the result must be zero anyway.  We prefer here to do it in the width of
-  // the induction variable because it helps a lot for certain cases; CodeGen
-  // isn't smart enough to ignore the overflow, which leads to much less
-  // efficient code if the width of the subtraction is wider than the native
-  // register width.
-  //
-  // (It's possible to not widen at all by pulling out factors of 2 before
-  // the multiplication; for example, K=2 can be calculated as
-  // It/2*(It+(It*INT_MIN/INT_MIN)+-1). However, it requires
-  // extra arithmetic, so it's not an obvious win, and it gets
-  // much more complicated for K > 3.)
-
-  // Protection from insane SCEVs; this bound is conservative,
-  // but it probably doesn't matter.
-  if (K > 1000)
-    return SE.getCouldNotCompute();
-
-  unsigned W = SE.getTypeSizeInBits(ResultTy);
-
-  // Calculate K! / 2^T and T; we divide out the factors of two before
-  // multiplying for calculating K! / 2^T to avoid overflow.
-  // Other overflow doesn't matter because we only care about the bottom
-  // W bits of the result.
-  APInt OddFactorial(W, 1);
-  unsigned T = 1;
-  for (unsigned i = 3; i <= K; ++i) {
-    APInt Mult(W, i);
-    unsigned TwoFactors = Mult.countTrailingZeros();
-    T += TwoFactors;
-    Mult.lshrInPlace(TwoFactors);
-    OddFactorial *= Mult;
-  }
-
-  // We need at least W + T bits for the multiplication step
-  unsigned CalculationBits = W + T;
-
-  // Calculate 2^T, at width T+W.
-  APInt DivFactor = APInt::getOneBitSet(CalculationBits, T);
-
-  // Calculate the multiplicative inverse of K! / 2^T;
-  // this multiplication factor will perform the exact division by
-  // K! / 2^T.
-  APInt Mod = APInt::getSignedMinValue(W+1);
-  APInt MultiplyFactor = OddFactorial.zext(W+1);
-  MultiplyFactor = MultiplyFactor.multiplicativeInverse(Mod);
-  MultiplyFactor = MultiplyFactor.trunc(W);
-
-  // Calculate the product, at width T+W
-  IntegerType *CalculationTy = IntegerType::get(SE.getContext(),
-                                                      CalculationBits);
-  const SCEV *Dividend = SE.getTruncateOrZeroExtend(It, CalculationTy);
-  for (unsigned i = 1; i != K; ++i) {
-    const SCEV *S = SE.getMinusSCEV(It, SE.getConstant(It->getType(), i));
-    Dividend = SE.getMulExpr(Dividend,
-                             SE.getTruncateOrZeroExtend(S, CalculationTy));
-  }
-
-  // Divide by 2^T
-  const SCEV *DivResult = SE.getUDivExpr(Dividend, SE.getConstant(DivFactor));
-
-  // Truncate the result, and divide by K! / 2^T.
-
-  return SE.getMulExpr(SE.getConstant(MultiplyFactor),
-                       SE.getTruncateOrZeroExtend(DivResult, ResultTy));
-}
-
-/// Return the value of this chain of recurrences at the specified iteration
-/// number.  We can evaluate this recurrence by multiplying each element in the
-/// chain by the binomial coefficient corresponding to it.  In other words, we
-/// can evaluate {A,+,B,+,C,+,D} as:
-///
-///   A*BC(It, 0) + B*BC(It, 1) + C*BC(It, 2) + D*BC(It, 3)
-///
-/// where BC(It, k) stands for binomial coefficient.
-const SCEV *SCEVAddRecExpr::evaluateAtIteration(const SCEV *It,
-                                                ScalarEvolution &SE) const {
-  const SCEV *Result = getStart();
-  for (unsigned i = 1, e = getNumOperands(); i != e; ++i) {
-    // The computation is correct in the face of overflow provided that the
-    // multiplication is performed _after_ the evaluation of the binomial
-    // coefficient.
-    const SCEV *Coeff = BinomialCoefficient(It, i, SE, getType());
-    if (isa<SCEVCouldNotCompute>(Coeff))
-      return Coeff;
-
-    Result = SE.getAddExpr(Result, SE.getMulExpr(getOperand(i), Coeff));
-  }
-  return Result;
-}
-
-//===----------------------------------------------------------------------===//
-//                    SCEV Expression folder implementations
-//===----------------------------------------------------------------------===//
-
-const SCEV *ScalarEvolution::getTruncateExpr(const SCEV *Op,
-                                             Type *Ty) {
-  assert(getTypeSizeInBits(Op->getType()) > getTypeSizeInBits(Ty) &&
-         "This is not a truncating conversion!");
-  assert(isSCEVable(Ty) &&
-         "This is not a conversion to a SCEVable type!");
-  Ty = getEffectiveSCEVType(Ty);
-
-  FoldingSetNodeID ID;
-  ID.AddInteger(scTruncate);
-  ID.AddPointer(Op);
-  ID.AddPointer(Ty);
-  void *IP = nullptr;
-  if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
-
-  // Fold if the operand is constant.
-  if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op))
-    return getConstant(
-      cast<ConstantInt>(ConstantExpr::getTrunc(SC->getValue(), Ty)));
-
-  // trunc(trunc(x)) --> trunc(x)
-  if (const SCEVTruncateExpr *ST = dyn_cast<SCEVTruncateExpr>(Op))
-    return getTruncateExpr(ST->getOperand(), Ty);
-
-  // trunc(sext(x)) --> sext(x) if widening or trunc(x) if narrowing
-  if (const SCEVSignExtendExpr *SS = dyn_cast<SCEVSignExtendExpr>(Op))
-    return getTruncateOrSignExtend(SS->getOperand(), Ty);
-
-  // trunc(zext(x)) --> zext(x) if widening or trunc(x) if narrowing
-  if (const SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op))
-    return getTruncateOrZeroExtend(SZ->getOperand(), Ty);
-
-  // trunc(x1 + ... + xN) --> trunc(x1) + ... + trunc(xN) and
-  // trunc(x1 * ... * xN) --> trunc(x1) * ... * trunc(xN),
-  // if after transforming we have at most one truncate, not counting truncates
-  // that replace other casts.
-  if (isa<SCEVAddExpr>(Op) || isa<SCEVMulExpr>(Op)) {
-    auto *CommOp = cast<SCEVCommutativeExpr>(Op);
-    SmallVector<const SCEV *, 4> Operands;
-    unsigned numTruncs = 0;
-    for (unsigned i = 0, e = CommOp->getNumOperands(); i != e && numTruncs < 2;
-         ++i) {
-      const SCEV *S = getTruncateExpr(CommOp->getOperand(i), Ty);
-      if (!isa<SCEVCastExpr>(CommOp->getOperand(i)) && isa<SCEVTruncateExpr>(S))
-        numTruncs++;
-      Operands.push_back(S);
-    }
-    if (numTruncs < 2) {
-      if (isa<SCEVAddExpr>(Op))
-        return getAddExpr(Operands);
-      else if (isa<SCEVMulExpr>(Op))
-        return getMulExpr(Operands);
-      else
-        llvm_unreachable("Unexpected SCEV type for Op.");
-    }
-    // Although we checked in the beginning that ID is not in the cache, it is
-    // possible that during recursion and different modification ID was inserted
-    // into the cache. So if we find it, just return it.
-    if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP))
-      return S;
-  }
-
-  // If the input value is a chrec scev, truncate the chrec's operands.
-  if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(Op)) {
-    SmallVector<const SCEV *, 4> Operands;
-    for (const SCEV *Op : AddRec->operands())
-      Operands.push_back(getTruncateExpr(Op, Ty));
-    return getAddRecExpr(Operands, AddRec->getLoop(), SCEV::FlagAnyWrap);
-  }
-
-  // The cast wasn't folded; create an explicit cast node. We can reuse
-  // the existing insert position since if we get here, we won't have
-  // made any changes which would invalidate it.
-  SCEV *S = new (SCEVAllocator) SCEVTruncateExpr(ID.Intern(SCEVAllocator),
-                                                 Op, Ty);
-  UniqueSCEVs.InsertNode(S, IP);
-  addToLoopUseLists(S);
-  return S;
-}
-
-// Get the limit of a recurrence such that incrementing by Step cannot cause
-// signed overflow as long as the value of the recurrence within the
-// loop does not exceed this limit before incrementing.
-static const SCEV *getSignedOverflowLimitForStep(const SCEV *Step,
-                                                 ICmpInst::Predicate *Pred,
-                                                 ScalarEvolution *SE) {
-  unsigned BitWidth = SE->getTypeSizeInBits(Step->getType());
-  if (SE->isKnownPositive(Step)) {
-    *Pred = ICmpInst::ICMP_SLT;
-    return SE->getConstant(APInt::getSignedMinValue(BitWidth) -
-                           SE->getSignedRangeMax(Step));
-  }
-  if (SE->isKnownNegative(Step)) {
-    *Pred = ICmpInst::ICMP_SGT;
-    return SE->getConstant(APInt::getSignedMaxValue(BitWidth) -
-                           SE->getSignedRangeMin(Step));
-  }
-  return nullptr;
-}
-
-// Get the limit of a recurrence such that incrementing by Step cannot cause
-// unsigned overflow as long as the value of the recurrence within the loop does
-// not exceed this limit before incrementing.
-static const SCEV *getUnsignedOverflowLimitForStep(const SCEV *Step,
-                                                   ICmpInst::Predicate *Pred,
-                                                   ScalarEvolution *SE) {
-  unsigned BitWidth = SE->getTypeSizeInBits(Step->getType());
-  *Pred = ICmpInst::ICMP_ULT;
-
-  return SE->getConstant(APInt::getMinValue(BitWidth) -
-                         SE->getUnsignedRangeMax(Step));
-}
-
-namespace {
-
-struct ExtendOpTraitsBase {
-  typedef const SCEV *(ScalarEvolution::*GetExtendExprTy)(const SCEV *, Type *,
-                                                          unsigned);
-};
-
-// Used to make code generic over signed and unsigned overflow.
-template <typename ExtendOp> struct ExtendOpTraits {
-  // Members present:
-  //
-  // static const SCEV::NoWrapFlags WrapType;
-  //
-  // static const ExtendOpTraitsBase::GetExtendExprTy GetExtendExpr;
-  //
-  // static const SCEV *getOverflowLimitForStep(const SCEV *Step,
-  //                                           ICmpInst::Predicate *Pred,
-  //                                           ScalarEvolution *SE);
-};
-
-template <>
-struct ExtendOpTraits<SCEVSignExtendExpr> : public ExtendOpTraitsBase {
-  static const SCEV::NoWrapFlags WrapType = SCEV::FlagNSW;
-
-  static const GetExtendExprTy GetExtendExpr;
-
-  static const SCEV *getOverflowLimitForStep(const SCEV *Step,
-                                             ICmpInst::Predicate *Pred,
-                                             ScalarEvolution *SE) {
-    return getSignedOverflowLimitForStep(Step, Pred, SE);
-  }
-};
-
-const ExtendOpTraitsBase::GetExtendExprTy ExtendOpTraits<
-    SCEVSignExtendExpr>::GetExtendExpr = &ScalarEvolution::getSignExtendExpr;
-
-template <>
-struct ExtendOpTraits<SCEVZeroExtendExpr> : public ExtendOpTraitsBase {
-  static const SCEV::NoWrapFlags WrapType = SCEV::FlagNUW;
-
-  static const GetExtendExprTy GetExtendExpr;
-
-  static const SCEV *getOverflowLimitForStep(const SCEV *Step,
-                                             ICmpInst::Predicate *Pred,
-                                             ScalarEvolution *SE) {
-    return getUnsignedOverflowLimitForStep(Step, Pred, SE);
-  }
-};
-
-const ExtendOpTraitsBase::GetExtendExprTy ExtendOpTraits<
-    SCEVZeroExtendExpr>::GetExtendExpr = &ScalarEvolution::getZeroExtendExpr;
-
-} // end anonymous namespace
-
-// The recurrence AR has been shown to have no signed/unsigned wrap or something
-// close to it. Typically, if we can prove NSW/NUW for AR, then we can just as
-// easily prove NSW/NUW for its preincrement or postincrement sibling. This
-// allows normalizing a sign/zero extended AddRec as such: {sext/zext(Step +
-// Start),+,Step} => {(Step + sext/zext(Start),+,Step} As a result, the
-// expression "Step + sext/zext(PreIncAR)" is congruent with
-// "sext/zext(PostIncAR)"
-template <typename ExtendOpTy>
-static const SCEV *getPreStartForExtend(const SCEVAddRecExpr *AR, Type *Ty,
-                                        ScalarEvolution *SE, unsigned Depth) {
-  auto WrapType = ExtendOpTraits<ExtendOpTy>::WrapType;
-  auto GetExtendExpr = ExtendOpTraits<ExtendOpTy>::GetExtendExpr;
-
-  const Loop *L = AR->getLoop();
-  const SCEV *Start = AR->getStart();
-  const SCEV *Step = AR->getStepRecurrence(*SE);
-
-  // Check for a simple looking step prior to loop entry.
-  const SCEVAddExpr *SA = dyn_cast<SCEVAddExpr>(Start);
-  if (!SA)
-    return nullptr;
-
-  // Create an AddExpr for "PreStart" after subtracting Step. Full SCEV
-  // subtraction is expensive. For this purpose, perform a quick and dirty
-  // difference, by checking for Step in the operand list.
-  SmallVector<const SCEV *, 4> DiffOps;
-  for (const SCEV *Op : SA->operands())
-    if (Op != Step)
-      DiffOps.push_back(Op);
-
-  if (DiffOps.size() == SA->getNumOperands())
-    return nullptr;
-
-  // Try to prove `WrapType` (SCEV::FlagNSW or SCEV::FlagNUW) on `PreStart` +
-  // `Step`:
-
-  // 1. NSW/NUW flags on the step increment.
-  auto PreStartFlags =
-    ScalarEvolution::maskFlags(SA->getNoWrapFlags(), SCEV::FlagNUW);
-  const SCEV *PreStart = SE->getAddExpr(DiffOps, PreStartFlags);
-  const SCEVAddRecExpr *PreAR = dyn_cast<SCEVAddRecExpr>(
-      SE->getAddRecExpr(PreStart, Step, L, SCEV::FlagAnyWrap));
-
-  // "{S,+,X} is <nsw>/<nuw>" and "the backedge is taken at least once" implies
-  // "S+X does not sign/unsign-overflow".
-  //
-
-  const SCEV *BECount = SE->getBackedgeTakenCount(L);
-  if (PreAR && PreAR->getNoWrapFlags(WrapType) &&
-      !isa<SCEVCouldNotCompute>(BECount) && SE->isKnownPositive(BECount))
-    return PreStart;
-
-  // 2. Direct overflow check on the step operation's expression.
-  unsigned BitWidth = SE->getTypeSizeInBits(AR->getType());
-  Type *WideTy = IntegerType::get(SE->getContext(), BitWidth * 2);
-  const SCEV *OperandExtendedStart =
-      SE->getAddExpr((SE->*GetExtendExpr)(PreStart, WideTy, Depth),
-                     (SE->*GetExtendExpr)(Step, WideTy, Depth));
-  if ((SE->*GetExtendExpr)(Start, WideTy, Depth) == OperandExtendedStart) {
-    if (PreAR && AR->getNoWrapFlags(WrapType)) {
-      // If we know `AR` == {`PreStart`+`Step`,+,`Step`} is `WrapType` (FlagNSW
-      // or FlagNUW) and that `PreStart` + `Step` is `WrapType` too, then
-      // `PreAR` == {`PreStart`,+,`Step`} is also `WrapType`.  Cache this fact.
-      const_cast<SCEVAddRecExpr *>(PreAR)->setNoWrapFlags(WrapType);
-    }
-    return PreStart;
-  }
-
-  // 3. Loop precondition.
-  ICmpInst::Predicate Pred;
-  const SCEV *OverflowLimit =
-      ExtendOpTraits<ExtendOpTy>::getOverflowLimitForStep(Step, &Pred, SE);
-
-  if (OverflowLimit &&
-      SE->isLoopEntryGuardedByCond(L, Pred, PreStart, OverflowLimit))
-    return PreStart;
-
-  return nullptr;
-}
-
-// Get the normalized zero or sign extended expression for this AddRec's Start.
-template <typename ExtendOpTy>
-static const SCEV *getExtendAddRecStart(const SCEVAddRecExpr *AR, Type *Ty,
-                                        ScalarEvolution *SE,
-                                        unsigned Depth) {
-  auto GetExtendExpr = ExtendOpTraits<ExtendOpTy>::GetExtendExpr;
-
-  const SCEV *PreStart = getPreStartForExtend<ExtendOpTy>(AR, Ty, SE, Depth);
-  if (!PreStart)
-    return (SE->*GetExtendExpr)(AR->getStart(), Ty, Depth);
-
-  return SE->getAddExpr((SE->*GetExtendExpr)(AR->getStepRecurrence(*SE), Ty,
-                                             Depth),
-                        (SE->*GetExtendExpr)(PreStart, Ty, Depth));
-}
-
-// Try to prove away overflow by looking at "nearby" add recurrences.  A
-// motivating example for this rule: if we know `{0,+,4}` is `ult` `-1` and it
-// does not itself wrap then we can conclude that `{1,+,4}` is `nuw`.
-//
-// Formally:
-//
-//     {S,+,X} == {S-T,+,X} + T
-//  => Ext({S,+,X}) == Ext({S-T,+,X} + T)
-//
-// If ({S-T,+,X} + T) does not overflow  ... (1)
-//
-//  RHS == Ext({S-T,+,X} + T) == Ext({S-T,+,X}) + Ext(T)
-//
-// If {S-T,+,X} does not overflow  ... (2)
-//
-//  RHS == Ext({S-T,+,X}) + Ext(T) == {Ext(S-T),+,Ext(X)} + Ext(T)
-//      == {Ext(S-T)+Ext(T),+,Ext(X)}
-//
-// If (S-T)+T does not overflow  ... (3)
-//
-//  RHS == {Ext(S-T)+Ext(T),+,Ext(X)} == {Ext(S-T+T),+,Ext(X)}
-//      == {Ext(S),+,Ext(X)} == LHS
-//
-// Thus, if (1), (2) and (3) are true for some T, then
-//   Ext({S,+,X}) == {Ext(S),+,Ext(X)}
-//
-// (3) is implied by (1) -- "(S-T)+T does not overflow" is simply "({S-T,+,X}+T)
-// does not overflow" restricted to the 0th iteration.  Therefore we only need
-// to check for (1) and (2).
-//
-// In the current context, S is `Start`, X is `Step`, Ext is `ExtendOpTy` and T
-// is `Delta` (defined below).
-template <typename ExtendOpTy>
-bool ScalarEvolution::proveNoWrapByVaryingStart(const SCEV *Start,
-                                                const SCEV *Step,
-                                                const Loop *L) {
-  auto WrapType = ExtendOpTraits<ExtendOpTy>::WrapType;
-
-  // We restrict `Start` to a constant to prevent SCEV from spending too much
-  // time here.  It is correct (but more expensive) to continue with a
-  // non-constant `Start` and do a general SCEV subtraction to compute
-  // `PreStart` below.
-  const SCEVConstant *StartC = dyn_cast<SCEVConstant>(Start);
-  if (!StartC)
-    return false;
-
-  APInt StartAI = StartC->getAPInt();
-
-  for (unsigned Delta : {-2, -1, 1, 2}) {
-    const SCEV *PreStart = getConstant(StartAI - Delta);
-
-    FoldingSetNodeID ID;
-    ID.AddInteger(scAddRecExpr);
-    ID.AddPointer(PreStart);
-    ID.AddPointer(Step);
-    ID.AddPointer(L);
-    void *IP = nullptr;
-    const auto *PreAR =
-      static_cast<SCEVAddRecExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP));
-
-    // Give up if we don't already have the add recurrence we need because
-    // actually constructing an add recurrence is relatively expensive.
-    if (PreAR && PreAR->getNoWrapFlags(WrapType)) {  // proves (2)
-      const SCEV *DeltaS = getConstant(StartC->getType(), Delta);
-      ICmpInst::Predicate Pred = ICmpInst::BAD_ICMP_PREDICATE;
-      const SCEV *Limit = ExtendOpTraits<ExtendOpTy>::getOverflowLimitForStep(
-          DeltaS, &Pred, this);
-      if (Limit && isKnownPredicate(Pred, PreAR, Limit))  // proves (1)
-        return true;
-    }
-  }
-
-  return false;
-}
-
-// Finds an integer D for an expression (C + x + y + ...) such that the top
-// level addition in (D + (C - D + x + y + ...)) would not wrap (signed or
-// unsigned) and the number of trailing zeros of (C - D + x + y + ...) is
-// maximized, where C is the \p ConstantTerm, x, y, ... are arbitrary SCEVs, and
-// the (C + x + y + ...) expression is \p WholeAddExpr.
-static APInt extractConstantWithoutWrapping(ScalarEvolution &SE,
-                                            const SCEVConstant *ConstantTerm,
-                                            const SCEVAddExpr *WholeAddExpr) {
-  const APInt C = ConstantTerm->getAPInt();
-  const unsigned BitWidth = C.getBitWidth();
-  // Find number of trailing zeros of (x + y + ...) w/o the C first:
-  uint32_t TZ = BitWidth;
-  for (unsigned I = 1, E = WholeAddExpr->getNumOperands(); I < E && TZ; ++I)
-    TZ = std::min(TZ, SE.GetMinTrailingZeros(WholeAddExpr->getOperand(I)));
-  if (TZ) {
-    // Set D to be as many least significant bits of C as possible while still
-    // guaranteeing that adding D to (C - D + x + y + ...) won't cause a wrap:
-    return TZ < BitWidth ? C.trunc(TZ).zext(BitWidth) : C;
-  }
-  return APInt(BitWidth, 0);
-}
-
-// Finds an integer D for an affine AddRec expression {C,+,x} such that the top
-// level addition in (D + {C-D,+,x}) would not wrap (signed or unsigned) and the
-// number of trailing zeros of (C - D + x * n) is maximized, where C is the \p
-// ConstantStart, x is an arbitrary \p Step, and n is the loop trip count.
-static APInt extractConstantWithoutWrapping(ScalarEvolution &SE,
-                                            const APInt &ConstantStart,
-                                            const SCEV *Step) {
-  const unsigned BitWidth = ConstantStart.getBitWidth();
-  const uint32_t TZ = SE.GetMinTrailingZeros(Step);
-  if (TZ)
-    return TZ < BitWidth ? ConstantStart.trunc(TZ).zext(BitWidth)
-                         : ConstantStart;
-  return APInt(BitWidth, 0);
-}
-
-const SCEV *
-ScalarEvolution::getZeroExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) {
-  assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&
-         "This is not an extending conversion!");
-  assert(isSCEVable(Ty) &&
-         "This is not a conversion to a SCEVable type!");
-  Ty = getEffectiveSCEVType(Ty);
-
-  // Fold if the operand is constant.
-  if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op))
-    return getConstant(
-      cast<ConstantInt>(ConstantExpr::getZExt(SC->getValue(), Ty)));
-
-  // zext(zext(x)) --> zext(x)
-  if (const SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op))
-    return getZeroExtendExpr(SZ->getOperand(), Ty, Depth + 1);
-
-  // Before doing any expensive analysis, check to see if we've already
-  // computed a SCEV for this Op and Ty.
-  FoldingSetNodeID ID;
-  ID.AddInteger(scZeroExtend);
-  ID.AddPointer(Op);
-  ID.AddPointer(Ty);
-  void *IP = nullptr;
-  if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
-  if (Depth > MaxExtDepth) {
-    SCEV *S = new (SCEVAllocator) SCEVZeroExtendExpr(ID.Intern(SCEVAllocator),
-                                                     Op, Ty);
-    UniqueSCEVs.InsertNode(S, IP);
-    addToLoopUseLists(S);
-    return S;
-  }
-
-  // zext(trunc(x)) --> zext(x) or x or trunc(x)
-  if (const SCEVTruncateExpr *ST = dyn_cast<SCEVTruncateExpr>(Op)) {
-    // It's possible the bits taken off by the truncate were all zero bits. If
-    // so, we should be able to simplify this further.
-    const SCEV *X = ST->getOperand();
-    ConstantRange CR = getUnsignedRange(X);
-    unsigned TruncBits = getTypeSizeInBits(ST->getType());
-    unsigned NewBits = getTypeSizeInBits(Ty);
-    if (CR.truncate(TruncBits).zeroExtend(NewBits).contains(
-            CR.zextOrTrunc(NewBits)))
-      return getTruncateOrZeroExtend(X, Ty);
-  }
-
-  // If the input value is a chrec scev, and we can prove that the value
-  // did not overflow the old, smaller, value, we can zero extend all of the
-  // operands (often constants).  This allows analysis of something like
-  // this:  for (unsigned char X = 0; X < 100; ++X) { int Y = X; }
-  if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Op))
-    if (AR->isAffine()) {
-      const SCEV *Start = AR->getStart();
-      const SCEV *Step = AR->getStepRecurrence(*this);
-      unsigned BitWidth = getTypeSizeInBits(AR->getType());
-      const Loop *L = AR->getLoop();
-
-      if (!AR->hasNoUnsignedWrap()) {
-        auto NewFlags = proveNoWrapViaConstantRanges(AR);
-        const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(NewFlags);
-      }
-
-      // If we have special knowledge that this addrec won't overflow,
-      // we don't need to do any further analysis.
-      if (AR->hasNoUnsignedWrap())
-        return getAddRecExpr(
-            getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this, Depth + 1),
-            getZeroExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags());
-
-      // Check whether the backedge-taken count is SCEVCouldNotCompute.
-      // Note that this serves two purposes: It filters out loops that are
-      // simply not analyzable, and it covers the case where this code is
-      // being called from within backedge-taken count analysis, such that
-      // attempting to ask for the backedge-taken count would likely result
-      // in infinite recursion. In the later case, the analysis code will
-      // cope with a conservative value, and it will take care to purge
-      // that value once it has finished.
-      const SCEV *MaxBECount = getMaxBackedgeTakenCount(L);
-      if (!isa<SCEVCouldNotCompute>(MaxBECount)) {
-        // Manually compute the final value for AR, checking for
-        // overflow.
-
-        // Check whether the backedge-taken count can be losslessly casted to
-        // the addrec's type. The count is always unsigned.
-        const SCEV *CastedMaxBECount =
-          getTruncateOrZeroExtend(MaxBECount, Start->getType());
-        const SCEV *RecastedMaxBECount =
-          getTruncateOrZeroExtend(CastedMaxBECount, MaxBECount->getType());
-        if (MaxBECount == RecastedMaxBECount) {
-          Type *WideTy = IntegerType::get(getContext(), BitWidth * 2);
-          // Check whether Start+Step*MaxBECount has no unsigned overflow.
-          const SCEV *ZMul = getMulExpr(CastedMaxBECount, Step,
-                                        SCEV::FlagAnyWrap, Depth + 1);
-          const SCEV *ZAdd = getZeroExtendExpr(getAddExpr(Start, ZMul,
-                                                          SCEV::FlagAnyWrap,
-                                                          Depth + 1),
-                                               WideTy, Depth + 1);
-          const SCEV *WideStart = getZeroExtendExpr(Start, WideTy, Depth + 1);
-          const SCEV *WideMaxBECount =
-            getZeroExtendExpr(CastedMaxBECount, WideTy, Depth + 1);
-          const SCEV *OperandExtendedAdd =
-            getAddExpr(WideStart,
-                       getMulExpr(WideMaxBECount,
-                                  getZeroExtendExpr(Step, WideTy, Depth + 1),
-                                  SCEV::FlagAnyWrap, Depth + 1),
-                       SCEV::FlagAnyWrap, Depth + 1);
-          if (ZAdd == OperandExtendedAdd) {
-            // Cache knowledge of AR NUW, which is propagated to this AddRec.
-            const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNUW);
-            // Return the expression with the addrec on the outside.
-            return getAddRecExpr(
-                getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this,
-                                                         Depth + 1),
-                getZeroExtendExpr(Step, Ty, Depth + 1), L,
-                AR->getNoWrapFlags());
-          }
-          // Similar to above, only this time treat the step value as signed.
-          // This covers loops that count down.
-          OperandExtendedAdd =
-            getAddExpr(WideStart,
-                       getMulExpr(WideMaxBECount,
-                                  getSignExtendExpr(Step, WideTy, Depth + 1),
-                                  SCEV::FlagAnyWrap, Depth + 1),
-                       SCEV::FlagAnyWrap, Depth + 1);
-          if (ZAdd == OperandExtendedAdd) {
-            // Cache knowledge of AR NW, which is propagated to this AddRec.
-            // Negative step causes unsigned wrap, but it still can't self-wrap.
-            const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNW);
-            // Return the expression with the addrec on the outside.
-            return getAddRecExpr(
-                getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this,
-                                                         Depth + 1),
-                getSignExtendExpr(Step, Ty, Depth + 1), L,
-                AR->getNoWrapFlags());
-          }
-        }
-      }
-
-      // Normally, in the cases we can prove no-overflow via a
-      // backedge guarding condition, we can also compute a backedge
-      // taken count for the loop.  The exceptions are assumptions and
-      // guards present in the loop -- SCEV is not great at exploiting
-      // these to compute max backedge taken counts, but can still use
-      // these to prove lack of overflow.  Use this fact to avoid
-      // doing extra work that may not pay off.
-      if (!isa<SCEVCouldNotCompute>(MaxBECount) || HasGuards ||
-          !AC.assumptions().empty()) {
-        // If the backedge is guarded by a comparison with the pre-inc
-        // value the addrec is safe. Also, if the entry is guarded by
-        // a comparison with the start value and the backedge is
-        // guarded by a comparison with the post-inc value, the addrec
-        // is safe.
-        if (isKnownPositive(Step)) {
-          const SCEV *N = getConstant(APInt::getMinValue(BitWidth) -
-                                      getUnsignedRangeMax(Step));
-          if (isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_ULT, AR, N) ||
-              isKnownOnEveryIteration(ICmpInst::ICMP_ULT, AR, N)) {
-            // Cache knowledge of AR NUW, which is propagated to this
-            // AddRec.
-            const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNUW);
-            // Return the expression with the addrec on the outside.
-            return getAddRecExpr(
-                getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this,
-                                                         Depth + 1),
-                getZeroExtendExpr(Step, Ty, Depth + 1), L,
-                AR->getNoWrapFlags());
-          }
-        } else if (isKnownNegative(Step)) {
-          const SCEV *N = getConstant(APInt::getMaxValue(BitWidth) -
-                                      getSignedRangeMin(Step));
-          if (isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_UGT, AR, N) ||
-              isKnownOnEveryIteration(ICmpInst::ICMP_UGT, AR, N)) {
-            // Cache knowledge of AR NW, which is propagated to this
-            // AddRec.  Negative step causes unsigned wrap, but it
-            // still can't self-wrap.
-            const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNW);
-            // Return the expression with the addrec on the outside.
-            return getAddRecExpr(
-                getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this,
-                                                         Depth + 1),
-                getSignExtendExpr(Step, Ty, Depth + 1), L,
-                AR->getNoWrapFlags());
-          }
-        }
-      }
-
-      // zext({C,+,Step}) --> (zext(D) + zext({C-D,+,Step}))<nuw><nsw>
-      // if D + (C - D + Step * n) could be proven to not unsigned wrap
-      // where D maximizes the number of trailing zeros of (C - D + Step * n)
-      if (const auto *SC = dyn_cast<SCEVConstant>(Start)) {
-        const APInt &C = SC->getAPInt();
-        const APInt &D = extractConstantWithoutWrapping(*this, C, Step);
-        if (D != 0) {
-          const SCEV *SZExtD = getZeroExtendExpr(getConstant(D), Ty, Depth);
-          const SCEV *SResidual =
-              getAddRecExpr(getConstant(C - D), Step, L, AR->getNoWrapFlags());
-          const SCEV *SZExtR = getZeroExtendExpr(SResidual, Ty, Depth + 1);
-          return getAddExpr(SZExtD, SZExtR,
-                            (SCEV::NoWrapFlags)(SCEV::FlagNSW | SCEV::FlagNUW),
-                            Depth + 1);
-        }
-      }
-
-      if (proveNoWrapByVaryingStart<SCEVZeroExtendExpr>(Start, Step, L)) {
-        const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNUW);
-        return getAddRecExpr(
-            getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this, Depth + 1),
-            getZeroExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags());
-      }
-    }
-
-  // zext(A % B) --> zext(A) % zext(B)
-  {
-    const SCEV *LHS;
-    const SCEV *RHS;
-    if (matchURem(Op, LHS, RHS))
-      return getURemExpr(getZeroExtendExpr(LHS, Ty, Depth + 1),
-                         getZeroExtendExpr(RHS, Ty, Depth + 1));
-  }
-
-  // zext(A / B) --> zext(A) / zext(B).
-  if (auto *Div = dyn_cast<SCEVUDivExpr>(Op))
-    return getUDivExpr(getZeroExtendExpr(Div->getLHS(), Ty, Depth + 1),
-                       getZeroExtendExpr(Div->getRHS(), Ty, Depth + 1));
-
-  if (auto *SA = dyn_cast<SCEVAddExpr>(Op)) {
-    // zext((A + B + ...)<nuw>) --> (zext(A) + zext(B) + ...)<nuw>
-    if (SA->hasNoUnsignedWrap()) {
-      // If the addition does not unsign overflow then we can, by definition,
-      // commute the zero extension with the addition operation.
-      SmallVector<const SCEV *, 4> Ops;
-      for (const auto *Op : SA->operands())
-        Ops.push_back(getZeroExtendExpr(Op, Ty, Depth + 1));
-      return getAddExpr(Ops, SCEV::FlagNUW, Depth + 1);
-    }
-
-    // zext(C + x + y + ...) --> (zext(D) + zext((C - D) + x + y + ...))
-    // if D + (C - D + x + y + ...) could be proven to not unsigned wrap
-    // where D maximizes the number of trailing zeros of (C - D + x + y + ...)
-    //
-    // Often address arithmetics contain expressions like
-    // (zext (add (shl X, C1), C2)), for instance, (zext (5 + (4 * X))).
-    // This transformation is useful while proving that such expressions are
-    // equal or differ by a small constant amount, see LoadStoreVectorizer pass.
-    if (const auto *SC = dyn_cast<SCEVConstant>(SA->getOperand(0))) {
-      const APInt &D = extractConstantWithoutWrapping(*this, SC, SA);
-      if (D != 0) {
-        const SCEV *SZExtD = getZeroExtendExpr(getConstant(D), Ty, Depth);
-        const SCEV *SResidual =
-            getAddExpr(getConstant(-D), SA, SCEV::FlagAnyWrap, Depth);
-        const SCEV *SZExtR = getZeroExtendExpr(SResidual, Ty, Depth + 1);
-        return getAddExpr(SZExtD, SZExtR,
-                          (SCEV::NoWrapFlags)(SCEV::FlagNSW | SCEV::FlagNUW),
-                          Depth + 1);
-      }
-    }
-  }
-
-  if (auto *SM = dyn_cast<SCEVMulExpr>(Op)) {
-    // zext((A * B * ...)<nuw>) --> (zext(A) * zext(B) * ...)<nuw>
-    if (SM->hasNoUnsignedWrap()) {
-      // If the multiply does not unsign overflow then we can, by definition,
-      // commute the zero extension with the multiply operation.
-      SmallVector<const SCEV *, 4> Ops;
-      for (const auto *Op : SM->operands())
-        Ops.push_back(getZeroExtendExpr(Op, Ty, Depth + 1));
-      return getMulExpr(Ops, SCEV::FlagNUW, Depth + 1);
-    }
-
-    // zext(2^K * (trunc X to iN)) to iM ->
-    // 2^K * (zext(trunc X to i{N-K}) to iM)<nuw>
-    //
-    // Proof:
-    //
-    //     zext(2^K * (trunc X to iN)) to iM
-    //   = zext((trunc X to iN) << K) to iM
-    //   = zext((trunc X to i{N-K}) << K)<nuw> to iM
-    //     (because shl removes the top K bits)
-    //   = zext((2^K * (trunc X to i{N-K}))<nuw>) to iM
-    //   = (2^K * (zext(trunc X to i{N-K}) to iM))<nuw>.
-    //
-    if (SM->getNumOperands() == 2)
-      if (auto *MulLHS = dyn_cast<SCEVConstant>(SM->getOperand(0)))
-        if (MulLHS->getAPInt().isPowerOf2())
-          if (auto *TruncRHS = dyn_cast<SCEVTruncateExpr>(SM->getOperand(1))) {
-            int NewTruncBits = getTypeSizeInBits(TruncRHS->getType()) -
-                               MulLHS->getAPInt().logBase2();
-            Type *NewTruncTy = IntegerType::get(getContext(), NewTruncBits);
-            return getMulExpr(
-                getZeroExtendExpr(MulLHS, Ty),
-                getZeroExtendExpr(
-                    getTruncateExpr(TruncRHS->getOperand(), NewTruncTy), Ty),
-                SCEV::FlagNUW, Depth + 1);
-          }
-  }
-
-  // The cast wasn't folded; create an explicit cast node.
-  // Recompute the insert position, as it may have been invalidated.
-  if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
-  SCEV *S = new (SCEVAllocator) SCEVZeroExtendExpr(ID.Intern(SCEVAllocator),
-                                                   Op, Ty);
-  UniqueSCEVs.InsertNode(S, IP);
-  addToLoopUseLists(S);
-  return S;
-}
-
-const SCEV *
-ScalarEvolution::getSignExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) {
-  assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&
-         "This is not an extending conversion!");
-  assert(isSCEVable(Ty) &&
-         "This is not a conversion to a SCEVable type!");
-  Ty = getEffectiveSCEVType(Ty);
-
-  // Fold if the operand is constant.
-  if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op))
-    return getConstant(
-      cast<ConstantInt>(ConstantExpr::getSExt(SC->getValue(), Ty)));
-
-  // sext(sext(x)) --> sext(x)
-  if (const SCEVSignExtendExpr *SS = dyn_cast<SCEVSignExtendExpr>(Op))
-    return getSignExtendExpr(SS->getOperand(), Ty, Depth + 1);
-
-  // sext(zext(x)) --> zext(x)
-  if (const SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op))
-    return getZeroExtendExpr(SZ->getOperand(), Ty, Depth + 1);
-
-  // Before doing any expensive analysis, check to see if we've already
-  // computed a SCEV for this Op and Ty.
-  FoldingSetNodeID ID;
-  ID.AddInteger(scSignExtend);
-  ID.AddPointer(Op);
-  ID.AddPointer(Ty);
-  void *IP = nullptr;
-  if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
-  // Limit recursion depth.
-  if (Depth > MaxExtDepth) {
-    SCEV *S = new (SCEVAllocator) SCEVSignExtendExpr(ID.Intern(SCEVAllocator),
-                                                     Op, Ty);
-    UniqueSCEVs.InsertNode(S, IP);
-    addToLoopUseLists(S);
-    return S;
-  }
-
-  // sext(trunc(x)) --> sext(x) or x or trunc(x)
-  if (const SCEVTruncateExpr *ST = dyn_cast<SCEVTruncateExpr>(Op)) {
-    // It's possible the bits taken off by the truncate were all sign bits. If
-    // so, we should be able to simplify this further.
-    const SCEV *X = ST->getOperand();
-    ConstantRange CR = getSignedRange(X);
-    unsigned TruncBits = getTypeSizeInBits(ST->getType());
-    unsigned NewBits = getTypeSizeInBits(Ty);
-    if (CR.truncate(TruncBits).signExtend(NewBits).contains(
-            CR.sextOrTrunc(NewBits)))
-      return getTruncateOrSignExtend(X, Ty);
-  }
-
-  if (auto *SA = dyn_cast<SCEVAddExpr>(Op)) {
-    // sext((A + B + ...)<nsw>) --> (sext(A) + sext(B) + ...)<nsw>
-    if (SA->hasNoSignedWrap()) {
-      // If the addition does not sign overflow then we can, by definition,
-      // commute the sign extension with the addition operation.
-      SmallVector<const SCEV *, 4> Ops;
-      for (const auto *Op : SA->operands())
-        Ops.push_back(getSignExtendExpr(Op, Ty, Depth + 1));
-      return getAddExpr(Ops, SCEV::FlagNSW, Depth + 1);
-    }
-
-    // sext(C + x + y + ...) --> (sext(D) + sext((C - D) + x + y + ...))
-    // if D + (C - D + x + y + ...) could be proven to not signed wrap
-    // where D maximizes the number of trailing zeros of (C - D + x + y + ...)
-    //
-    // For instance, this will bring two seemingly different expressions:
-    //     1 + sext(5 + 20 * %x + 24 * %y)  and
-    //         sext(6 + 20 * %x + 24 * %y)
-    // to the same form:
-    //     2 + sext(4 + 20 * %x + 24 * %y)
-    if (const auto *SC = dyn_cast<SCEVConstant>(SA->getOperand(0))) {
-      const APInt &D = extractConstantWithoutWrapping(*this, SC, SA);
-      if (D != 0) {
-        const SCEV *SSExtD = getSignExtendExpr(getConstant(D), Ty, Depth);
-        const SCEV *SResidual =
-            getAddExpr(getConstant(-D), SA, SCEV::FlagAnyWrap, Depth);
-        const SCEV *SSExtR = getSignExtendExpr(SResidual, Ty, Depth + 1);
-        return getAddExpr(SSExtD, SSExtR,
-                          (SCEV::NoWrapFlags)(SCEV::FlagNSW | SCEV::FlagNUW),
-                          Depth + 1);
-      }
-    }
-  }
-  // If the input value is a chrec scev, and we can prove that the value
-  // did not overflow the old, smaller, value, we can sign extend all of the
-  // operands (often constants).  This allows analysis of something like
-  // this:  for (signed char X = 0; X < 100; ++X) { int Y = X; }
-  if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Op))
-    if (AR->isAffine()) {
-      const SCEV *Start = AR->getStart();
-      const SCEV *Step = AR->getStepRecurrence(*this);
-      unsigned BitWidth = getTypeSizeInBits(AR->getType());
-      const Loop *L = AR->getLoop();
-
-      if (!AR->hasNoSignedWrap()) {
-        auto NewFlags = proveNoWrapViaConstantRanges(AR);
-        const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(NewFlags);
-      }
-
-      // If we have special knowledge that this addrec won't overflow,
-      // we don't need to do any further analysis.
-      if (AR->hasNoSignedWrap())
-        return getAddRecExpr(
-            getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, Depth + 1),
-            getSignExtendExpr(Step, Ty, Depth + 1), L, SCEV::FlagNSW);
-
-      // Check whether the backedge-taken count is SCEVCouldNotCompute.
-      // Note that this serves two purposes: It filters out loops that are
-      // simply not analyzable, and it covers the case where this code is
-      // being called from within backedge-taken count analysis, such that
-      // attempting to ask for the backedge-taken count would likely result
-      // in infinite recursion. In the later case, the analysis code will
-      // cope with a conservative value, and it will take care to purge
-      // that value once it has finished.
-      const SCEV *MaxBECount = getMaxBackedgeTakenCount(L);
-      if (!isa<SCEVCouldNotCompute>(MaxBECount)) {
-        // Manually compute the final value for AR, checking for
-        // overflow.
-
-        // Check whether the backedge-taken count can be losslessly casted to
-        // the addrec's type. The count is always unsigned.
-        const SCEV *CastedMaxBECount =
-          getTruncateOrZeroExtend(MaxBECount, Start->getType());
-        const SCEV *RecastedMaxBECount =
-          getTruncateOrZeroExtend(CastedMaxBECount, MaxBECount->getType());
-        if (MaxBECount == RecastedMaxBECount) {
-          Type *WideTy = IntegerType::get(getContext(), BitWidth * 2);
-          // Check whether Start+Step*MaxBECount has no signed overflow.
-          const SCEV *SMul = getMulExpr(CastedMaxBECount, Step,
-                                        SCEV::FlagAnyWrap, Depth + 1);
-          const SCEV *SAdd = getSignExtendExpr(getAddExpr(Start, SMul,
-                                                          SCEV::FlagAnyWrap,
-                                                          Depth + 1),
-                                               WideTy, Depth + 1);
-          const SCEV *WideStart = getSignExtendExpr(Start, WideTy, Depth + 1);
-          const SCEV *WideMaxBECount =
-            getZeroExtendExpr(CastedMaxBECount, WideTy, Depth + 1);
-          const SCEV *OperandExtendedAdd =
-            getAddExpr(WideStart,
-                       getMulExpr(WideMaxBECount,
-                                  getSignExtendExpr(Step, WideTy, Depth + 1),
-                                  SCEV::FlagAnyWrap, Depth + 1),
-                       SCEV::FlagAnyWrap, Depth + 1);
-          if (SAdd == OperandExtendedAdd) {
-            // Cache knowledge of AR NSW, which is propagated to this AddRec.
-            const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNSW);
-            // Return the expression with the addrec on the outside.
-            return getAddRecExpr(
-                getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this,
-                                                         Depth + 1),
-                getSignExtendExpr(Step, Ty, Depth + 1), L,
-                AR->getNoWrapFlags());
-          }
-          // Similar to above, only this time treat the step value as unsigned.
-          // This covers loops that count up with an unsigned step.
-          OperandExtendedAdd =
-            getAddExpr(WideStart,
-                       getMulExpr(WideMaxBECount,
-                                  getZeroExtendExpr(Step, WideTy, Depth + 1),
-                                  SCEV::FlagAnyWrap, Depth + 1),
-                       SCEV::FlagAnyWrap, Depth + 1);
-          if (SAdd == OperandExtendedAdd) {
-            // If AR wraps around then
-            //
-            //    abs(Step) * MaxBECount > unsigned-max(AR->getType())
-            // => SAdd != OperandExtendedAdd
-            //
-            // Thus (AR is not NW => SAdd != OperandExtendedAdd) <=>
-            // (SAdd == OperandExtendedAdd => AR is NW)
-
-            const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNW);
-
-            // Return the expression with the addrec on the outside.
-            return getAddRecExpr(
-                getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this,
-                                                         Depth + 1),
-                getZeroExtendExpr(Step, Ty, Depth + 1), L,
-                AR->getNoWrapFlags());
-          }
-        }
-      }
-
-      // Normally, in the cases we can prove no-overflow via a
-      // backedge guarding condition, we can also compute a backedge
-      // taken count for the loop.  The exceptions are assumptions and
-      // guards present in the loop -- SCEV is not great at exploiting
-      // these to compute max backedge taken counts, but can still use
-      // these to prove lack of overflow.  Use this fact to avoid
-      // doing extra work that may not pay off.
-
-      if (!isa<SCEVCouldNotCompute>(MaxBECount) || HasGuards ||
-          !AC.assumptions().empty()) {
-        // If the backedge is guarded by a comparison with the pre-inc
-        // value the addrec is safe. Also, if the entry is guarded by
-        // a comparison with the start value and the backedge is
-        // guarded by a comparison with the post-inc value, the addrec
-        // is safe.
-        ICmpInst::Predicate Pred;
-        const SCEV *OverflowLimit =
-            getSignedOverflowLimitForStep(Step, &Pred, this);
-        if (OverflowLimit &&
-            (isLoopBackedgeGuardedByCond(L, Pred, AR, OverflowLimit) ||
-             isKnownOnEveryIteration(Pred, AR, OverflowLimit))) {
-          // Cache knowledge of AR NSW, then propagate NSW to the wide AddRec.
-          const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNSW);
-          return getAddRecExpr(
-              getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, Depth + 1),
-              getSignExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags());
-        }
-      }
-
-      // sext({C,+,Step}) --> (sext(D) + sext({C-D,+,Step}))<nuw><nsw>
-      // if D + (C - D + Step * n) could be proven to not signed wrap
-      // where D maximizes the number of trailing zeros of (C - D + Step * n)
-      if (const auto *SC = dyn_cast<SCEVConstant>(Start)) {
-        const APInt &C = SC->getAPInt();
-        const APInt &D = extractConstantWithoutWrapping(*this, C, Step);
-        if (D != 0) {
-          const SCEV *SSExtD = getSignExtendExpr(getConstant(D), Ty, Depth);
-          const SCEV *SResidual =
-              getAddRecExpr(getConstant(C - D), Step, L, AR->getNoWrapFlags());
-          const SCEV *SSExtR = getSignExtendExpr(SResidual, Ty, Depth + 1);
-          return getAddExpr(SSExtD, SSExtR,
-                            (SCEV::NoWrapFlags)(SCEV::FlagNSW | SCEV::FlagNUW),
-                            Depth + 1);
-        }
-      }
-
-      if (proveNoWrapByVaryingStart<SCEVSignExtendExpr>(Start, Step, L)) {
-        const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNSW);
-        return getAddRecExpr(
-            getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, Depth + 1),
-            getSignExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags());
-      }
-    }
-
-  // If the input value is provably positive and we could not simplify
-  // away the sext build a zext instead.
-  if (isKnownNonNegative(Op))
-    return getZeroExtendExpr(Op, Ty, Depth + 1);
-
-  // The cast wasn't folded; create an explicit cast node.
-  // Recompute the insert position, as it may have been invalidated.
-  if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
-  SCEV *S = new (SCEVAllocator) SCEVSignExtendExpr(ID.Intern(SCEVAllocator),
-                                                   Op, Ty);
-  UniqueSCEVs.InsertNode(S, IP);
-  addToLoopUseLists(S);
-  return S;
-}
-
-/// getAnyExtendExpr - Return a SCEV for the given operand extended with
-/// unspecified bits out to the given type.
-const SCEV *ScalarEvolution::getAnyExtendExpr(const SCEV *Op,
-                                              Type *Ty) {
-  assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&
-         "This is not an extending conversion!");
-  assert(isSCEVable(Ty) &&
-         "This is not a conversion to a SCEVable type!");
-  Ty = getEffectiveSCEVType(Ty);
-
-  // Sign-extend negative constants.
-  if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op))
-    if (SC->getAPInt().isNegative())
-      return getSignExtendExpr(Op, Ty);
-
-  // Peel off a truncate cast.
-  if (const SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(Op)) {
-    const SCEV *NewOp = T->getOperand();
-    if (getTypeSizeInBits(NewOp->getType()) < getTypeSizeInBits(Ty))
-      return getAnyExtendExpr(NewOp, Ty);
-    return getTruncateOrNoop(NewOp, Ty);
-  }
-
-  // Next try a zext cast. If the cast is folded, use it.
-  const SCEV *ZExt = getZeroExtendExpr(Op, Ty);
-  if (!isa<SCEVZeroExtendExpr>(ZExt))
-    return ZExt;
-
-  // Next try a sext cast. If the cast is folded, use it.
-  const SCEV *SExt = getSignExtendExpr(Op, Ty);
-  if (!isa<SCEVSignExtendExpr>(SExt))
-    return SExt;
-
-  // Force the cast to be folded into the operands of an addrec.
-  if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Op)) {
-    SmallVector<const SCEV *, 4> Ops;
-    for (const SCEV *Op : AR->operands())
-      Ops.push_back(getAnyExtendExpr(Op, Ty));
-    return getAddRecExpr(Ops, AR->getLoop(), SCEV::FlagNW);
-  }
-
-  // If the expression is obviously signed, use the sext cast value.
-  if (isa<SCEVSMaxExpr>(Op))
-    return SExt;
-
-  // Absent any other information, use the zext cast value.
-  return ZExt;
-}
-
-/// Process the given Ops list, which is a list of operands to be added under
-/// the given scale, update the given map. This is a helper function for
-/// getAddRecExpr. As an example of what it does, given a sequence of operands
-/// that would form an add expression like this:
-///
-///    m + n + 13 + (A * (o + p + (B * (q + m + 29)))) + r + (-1 * r)
-///
-/// where A and B are constants, update the map with these values:
-///
-///    (m, 1+A*B), (n, 1), (o, A), (p, A), (q, A*B), (r, 0)
-///
-/// and add 13 + A*B*29 to AccumulatedConstant.
-/// This will allow getAddRecExpr to produce this:
-///
-///    13+A*B*29 + n + (m * (1+A*B)) + ((o + p) * A) + (q * A*B)
-///
-/// This form often exposes folding opportunities that are hidden in
-/// the original operand list.
-///
-/// Return true iff it appears that any interesting folding opportunities
-/// may be exposed. This helps getAddRecExpr short-circuit extra work in
-/// the common case where no interesting opportunities are present, and
-/// is also used as a check to avoid infinite recursion.
-static bool
-CollectAddOperandsWithScales(DenseMap<const SCEV *, APInt> &M,
-                             SmallVectorImpl<const SCEV *> &NewOps,
-                             APInt &AccumulatedConstant,
-                             const SCEV *const *Ops, size_t NumOperands,
-                             const APInt &Scale,
-                             ScalarEvolution &SE) {
-  bool Interesting = false;
-
-  // Iterate over the add operands. They are sorted, with constants first.
-  unsigned i = 0;
-  while (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[i])) {
-    ++i;
-    // Pull a buried constant out to the outside.
-    if (Scale != 1 || AccumulatedConstant != 0 || C->getValue()->isZero())
-      Interesting = true;
-    AccumulatedConstant += Scale * C->getAPInt();
-  }
-
-  // Next comes everything else. We're especially interested in multiplies
-  // here, but they're in the middle, so just visit the rest with one loop.
-  for (; i != NumOperands; ++i) {
-    const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(Ops[i]);
-    if (Mul && isa<SCEVConstant>(Mul->getOperand(0))) {
-      APInt NewScale =
-          Scale * cast<SCEVConstant>(Mul->getOperand(0))->getAPInt();
-      if (Mul->getNumOperands() == 2 && isa<SCEVAddExpr>(Mul->getOperand(1))) {
-        // A multiplication of a constant with another add; recurse.
-        const SCEVAddExpr *Add = cast<SCEVAddExpr>(Mul->getOperand(1));
-        Interesting |=
-          CollectAddOperandsWithScales(M, NewOps, AccumulatedConstant,
-                                       Add->op_begin(), Add->getNumOperands(),
-                                       NewScale, SE);
-      } else {
-        // A multiplication of a constant with some other value. Update
-        // the map.
-        SmallVector<const SCEV *, 4> MulOps(Mul->op_begin()+1, Mul->op_end());
-        const SCEV *Key = SE.getMulExpr(MulOps);
-        auto Pair = M.insert({Key, NewScale});
-        if (Pair.second) {
-          NewOps.push_back(Pair.first->first);
-        } else {
-          Pair.first->second += NewScale;
-          // The map already had an entry for this value, which may indicate
-          // a folding opportunity.
-          Interesting = true;
-        }
-      }
-    } else {
-      // An ordinary operand. Update the map.
-      std::pair<DenseMap<const SCEV *, APInt>::iterator, bool> Pair =
-          M.insert({Ops[i], Scale});
-      if (Pair.second) {
-        NewOps.push_back(Pair.first->first);
-      } else {
-        Pair.first->second += Scale;
-        // The map already had an entry for this value, which may indicate
-        // a folding opportunity.
-        Interesting = true;
-      }
-    }
-  }
-
-  return Interesting;
-}
-
-// We're trying to construct a SCEV of type `Type' with `Ops' as operands and
-// `OldFlags' as can't-wrap behavior.  Infer a more aggressive set of
-// can't-overflow flags for the operation if possible.
-static SCEV::NoWrapFlags
-StrengthenNoWrapFlags(ScalarEvolution *SE, SCEVTypes Type,
-                      const SmallVectorImpl<const SCEV *> &Ops,
-                      SCEV::NoWrapFlags Flags) {
-  using namespace std::placeholders;
-
-  using OBO = OverflowingBinaryOperator;
-
-  bool CanAnalyze =
-      Type == scAddExpr || Type == scAddRecExpr || Type == scMulExpr;
-  (void)CanAnalyze;
-  assert(CanAnalyze && "don't call from other places!");
-
-  int SignOrUnsignMask = SCEV::FlagNUW | SCEV::FlagNSW;
-  SCEV::NoWrapFlags SignOrUnsignWrap =
-      ScalarEvolution::maskFlags(Flags, SignOrUnsignMask);
-
-  // If FlagNSW is true and all the operands are non-negative, infer FlagNUW.
-  auto IsKnownNonNegative = [&](const SCEV *S) {
-    return SE->isKnownNonNegative(S);
-  };
-
-  if (SignOrUnsignWrap == SCEV::FlagNSW && all_of(Ops, IsKnownNonNegative))
-    Flags =
-        ScalarEvolution::setFlags(Flags, (SCEV::NoWrapFlags)SignOrUnsignMask);
-
-  SignOrUnsignWrap = ScalarEvolution::maskFlags(Flags, SignOrUnsignMask);
-
-  if (SignOrUnsignWrap != SignOrUnsignMask &&
-      (Type == scAddExpr || Type == scMulExpr) && Ops.size() == 2 &&
-      isa<SCEVConstant>(Ops[0])) {
-
-    auto Opcode = [&] {
-      switch (Type) {
-      case scAddExpr:
-        return Instruction::Add;
-      case scMulExpr:
-        return Instruction::Mul;
-      default:
-        llvm_unreachable("Unexpected SCEV op.");
-      }
-    }();
-
-    const APInt &C = cast<SCEVConstant>(Ops[0])->getAPInt();
-
-    // (A <opcode> C) --> (A <opcode> C)<nsw> if the op doesn't sign overflow.
-    if (!(SignOrUnsignWrap & SCEV::FlagNSW)) {
-      auto NSWRegion = ConstantRange::makeGuaranteedNoWrapRegion(
-          Opcode, C, OBO::NoSignedWrap);
-      if (NSWRegion.contains(SE->getSignedRange(Ops[1])))
-        Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNSW);
-    }
-
-    // (A <opcode> C) --> (A <opcode> C)<nuw> if the op doesn't unsign overflow.
-    if (!(SignOrUnsignWrap & SCEV::FlagNUW)) {
-      auto NUWRegion = ConstantRange::makeGuaranteedNoWrapRegion(
-          Opcode, C, OBO::NoUnsignedWrap);
-      if (NUWRegion.contains(SE->getUnsignedRange(Ops[1])))
-        Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNUW);
-    }
-  }
-
-  return Flags;
-}
-
-bool ScalarEvolution::isAvailableAtLoopEntry(const SCEV *S, const Loop *L) {
-  return isLoopInvariant(S, L) && properlyDominates(S, L->getHeader());
-}
-
-/// Get a canonical add expression, or something simpler if possible.
-const SCEV *ScalarEvolution::getAddExpr(SmallVectorImpl<const SCEV *> &Ops,
-                                        SCEV::NoWrapFlags Flags,
-                                        unsigned Depth) {
-  assert(!(Flags & ~(SCEV::FlagNUW | SCEV::FlagNSW)) &&
-         "only nuw or nsw allowed");
-  assert(!Ops.empty() && "Cannot get empty add!");
-  if (Ops.size() == 1) return Ops[0];
-#ifndef NDEBUG
-  Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
-  for (unsigned i = 1, e = Ops.size(); i != e; ++i)
-    assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
-           "SCEVAddExpr operand types don't match!");
-#endif
-
-  // Sort by complexity, this groups all similar expression types together.
-  GroupByComplexity(Ops, &LI, DT);
-
-  Flags = StrengthenNoWrapFlags(this, scAddExpr, Ops, Flags);
-
-  // If there are any constants, fold them together.
-  unsigned Idx = 0;
-  if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
-    ++Idx;
-    assert(Idx < Ops.size());
-    while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) {
-      // We found two constants, fold them together!
-      Ops[0] = getConstant(LHSC->getAPInt() + RHSC->getAPInt());
-      if (Ops.size() == 2) return Ops[0];
-      Ops.erase(Ops.begin()+1);  // Erase the folded element
-      LHSC = cast<SCEVConstant>(Ops[0]);
-    }
-
-    // If we are left with a constant zero being added, strip it off.
-    if (LHSC->getValue()->isZero()) {
-      Ops.erase(Ops.begin());
-      --Idx;
-    }
-
-    if (Ops.size() == 1) return Ops[0];
-  }
-
-  // Limit recursion calls depth.
-  if (Depth > MaxArithDepth)
-    return getOrCreateAddExpr(Ops, Flags);
-
-  // Okay, check to see if the same value occurs in the operand list more than
-  // once.  If so, merge them together into an multiply expression.  Since we
-  // sorted the list, these values are required to be adjacent.
-  Type *Ty = Ops[0]->getType();
-  bool FoundMatch = false;
-  for (unsigned i = 0, e = Ops.size(); i != e-1; ++i)
-    if (Ops[i] == Ops[i+1]) {      //  X + Y + Y  -->  X + Y*2
-      // Scan ahead to count how many equal operands there are.
-      unsigned Count = 2;
-      while (i+Count != e && Ops[i+Count] == Ops[i])
-        ++Count;
-      // Merge the values into a multiply.
-      const SCEV *Scale = getConstant(Ty, Count);
-      const SCEV *Mul = getMulExpr(Scale, Ops[i], SCEV::FlagAnyWrap, Depth + 1);
-      if (Ops.size() == Count)
-        return Mul;
-      Ops[i] = Mul;
-      Ops.erase(Ops.begin()+i+1, Ops.begin()+i+Count);
-      --i; e -= Count - 1;
-      FoundMatch = true;
-    }
-  if (FoundMatch)
-    return getAddExpr(Ops, Flags, Depth + 1);
-
-  // Check for truncates. If all the operands are truncated from the same
-  // type, see if factoring out the truncate would permit the result to be
-  // folded. eg., n*trunc(x) + m*trunc(y) --> trunc(trunc(m)*x + trunc(n)*y)
-  // if the contents of the resulting outer trunc fold to something simple.
-  auto FindTruncSrcType = [&]() -> Type * {
-    // We're ultimately looking to fold an addrec of truncs and muls of only
-    // constants and truncs, so if we find any other types of SCEV
-    // as operands of the addrec then we bail and return nullptr here.
-    // Otherwise, we return the type of the operand of a trunc that we find.
-    if (auto *T = dyn_cast<SCEVTruncateExpr>(Ops[Idx]))
-      return T->getOperand()->getType();
-    if (const auto *Mul = dyn_cast<SCEVMulExpr>(Ops[Idx])) {
-      const auto *LastOp = Mul->getOperand(Mul->getNumOperands() - 1);
-      if (const auto *T = dyn_cast<SCEVTruncateExpr>(LastOp))
-        return T->getOperand()->getType();
-    }
-    return nullptr;
-  };
-  if (auto *SrcType = FindTruncSrcType()) {
-    SmallVector<const SCEV *, 8> LargeOps;
-    bool Ok = true;
-    // Check all the operands to see if they can be represented in the
-    // source type of the truncate.
-    for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
-      if (const SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(Ops[i])) {
-        if (T->getOperand()->getType() != SrcType) {
-          Ok = false;
-          break;
-        }
-        LargeOps.push_back(T->getOperand());
-      } else if (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[i])) {
-        LargeOps.push_back(getAnyExtendExpr(C, SrcType));
-      } else if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(Ops[i])) {
-        SmallVector<const SCEV *, 8> LargeMulOps;
-        for (unsigned j = 0, f = M->getNumOperands(); j != f && Ok; ++j) {
-          if (const SCEVTruncateExpr *T =
-                dyn_cast<SCEVTruncateExpr>(M->getOperand(j))) {
-            if (T->getOperand()->getType() != SrcType) {
-              Ok = false;
-              break;
-            }
-            LargeMulOps.push_back(T->getOperand());
-          } else if (const auto *C = dyn_cast<SCEVConstant>(M->getOperand(j))) {
-            LargeMulOps.push_back(getAnyExtendExpr(C, SrcType));
-          } else {
-            Ok = false;
-            break;
-          }
-        }
-        if (Ok)
-          LargeOps.push_back(getMulExpr(LargeMulOps, SCEV::FlagAnyWrap, Depth + 1));
-      } else {
-        Ok = false;
-        break;
-      }
-    }
-    if (Ok) {
-      // Evaluate the expression in the larger type.
-      const SCEV *Fold = getAddExpr(LargeOps, SCEV::FlagAnyWrap, Depth + 1);
-      // If it folds to something simple, use it. Otherwise, don't.
-      if (isa<SCEVConstant>(Fold) || isa<SCEVUnknown>(Fold))
-        return getTruncateExpr(Fold, Ty);
-    }
-  }
-
-  // Skip past any other cast SCEVs.
-  while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scAddExpr)
-    ++Idx;
-
-  // If there are add operands they would be next.
-  if (Idx < Ops.size()) {
-    bool DeletedAdd = false;
-    while (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[Idx])) {
-      if (Ops.size() > AddOpsInlineThreshold ||
-          Add->getNumOperands() > AddOpsInlineThreshold)
-        break;
-      // If we have an add, expand the add operands onto the end of the operands
-      // list.
-      Ops.erase(Ops.begin()+Idx);
-      Ops.append(Add->op_begin(), Add->op_end());
-      DeletedAdd = true;
-    }
-
-    // If we deleted at least one add, we added operands to the end of the list,
-    // and they are not necessarily sorted.  Recurse to resort and resimplify
-    // any operands we just acquired.
-    if (DeletedAdd)
-      return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);
-  }
-
-  // Skip over the add expression until we get to a multiply.
-  while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scMulExpr)
-    ++Idx;
-
-  // Check to see if there are any folding opportunities present with
-  // operands multiplied by constant values.
-  if (Idx < Ops.size() && isa<SCEVMulExpr>(Ops[Idx])) {
-    uint64_t BitWidth = getTypeSizeInBits(Ty);
-    DenseMap<const SCEV *, APInt> M;
-    SmallVector<const SCEV *, 8> NewOps;
-    APInt AccumulatedConstant(BitWidth, 0);
-    if (CollectAddOperandsWithScales(M, NewOps, AccumulatedConstant,
-                                     Ops.data(), Ops.size(),
-                                     APInt(BitWidth, 1), *this)) {
-      struct APIntCompare {
-        bool operator()(const APInt &LHS, const APInt &RHS) const {
-          return LHS.ult(RHS);
-        }
-      };
-
-      // Some interesting folding opportunity is present, so its worthwhile to
-      // re-generate the operands list. Group the operands by constant scale,
-      // to avoid multiplying by the same constant scale multiple times.
-      std::map<APInt, SmallVector<const SCEV *, 4>, APIntCompare> MulOpLists;
-      for (const SCEV *NewOp : NewOps)
-        MulOpLists[M.find(NewOp)->second].push_back(NewOp);
-      // Re-generate the operands list.
-      Ops.clear();
-      if (AccumulatedConstant != 0)
-        Ops.push_back(getConstant(AccumulatedConstant));
-      for (auto &MulOp : MulOpLists)
-        if (MulOp.first != 0)
-          Ops.push_back(getMulExpr(
-              getConstant(MulOp.first),
-              getAddExpr(MulOp.second, SCEV::FlagAnyWrap, Depth + 1),
-              SCEV::FlagAnyWrap, Depth + 1));
-      if (Ops.empty())
-        return getZero(Ty);
-      if (Ops.size() == 1)
-        return Ops[0];
-      return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);
-    }
-  }
-
-  // If we are adding something to a multiply expression, make sure the
-  // something is not already an operand of the multiply.  If so, merge it into
-  // the multiply.
-  for (; Idx < Ops.size() && isa<SCEVMulExpr>(Ops[Idx]); ++Idx) {
-    const SCEVMulExpr *Mul = cast<SCEVMulExpr>(Ops[Idx]);
-    for (unsigned MulOp = 0, e = Mul->getNumOperands(); MulOp != e; ++MulOp) {
-      const SCEV *MulOpSCEV = Mul->getOperand(MulOp);
-      if (isa<SCEVConstant>(MulOpSCEV))
-        continue;
-      for (unsigned AddOp = 0, e = Ops.size(); AddOp != e; ++AddOp)
-        if (MulOpSCEV == Ops[AddOp]) {
-          // Fold W + X + (X * Y * Z)  -->  W + (X * ((Y*Z)+1))
-          const SCEV *InnerMul = Mul->getOperand(MulOp == 0);
-          if (Mul->getNumOperands() != 2) {
-            // If the multiply has more than two operands, we must get the
-            // Y*Z term.
-            SmallVector<const SCEV *, 4> MulOps(Mul->op_begin(),
-                                                Mul->op_begin()+MulOp);
-            MulOps.append(Mul->op_begin()+MulOp+1, Mul->op_end());
-            InnerMul = getMulExpr(MulOps, SCEV::FlagAnyWrap, Depth + 1);
-          }
-          SmallVector<const SCEV *, 2> TwoOps = {getOne(Ty), InnerMul};
-          const SCEV *AddOne = getAddExpr(TwoOps, SCEV::FlagAnyWrap, Depth + 1);
-          const SCEV *OuterMul = getMulExpr(AddOne, MulOpSCEV,
-                                            SCEV::FlagAnyWrap, Depth + 1);
-          if (Ops.size() == 2) return OuterMul;
-          if (AddOp < Idx) {
-            Ops.erase(Ops.begin()+AddOp);
-            Ops.erase(Ops.begin()+Idx-1);
-          } else {
-            Ops.erase(Ops.begin()+Idx);
-            Ops.erase(Ops.begin()+AddOp-1);
-          }
-          Ops.push_back(OuterMul);
-          return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);
-        }
-
-      // Check this multiply against other multiplies being added together.
-      for (unsigned OtherMulIdx = Idx+1;
-           OtherMulIdx < Ops.size() && isa<SCEVMulExpr>(Ops[OtherMulIdx]);
-           ++OtherMulIdx) {
-        const SCEVMulExpr *OtherMul = cast<SCEVMulExpr>(Ops[OtherMulIdx]);
-        // If MulOp occurs in OtherMul, we can fold the two multiplies
-        // together.
-        for (unsigned OMulOp = 0, e = OtherMul->getNumOperands();
-             OMulOp != e; ++OMulOp)
-          if (OtherMul->getOperand(OMulOp) == MulOpSCEV) {
-            // Fold X + (A*B*C) + (A*D*E) --> X + (A*(B*C+D*E))
-            const SCEV *InnerMul1 = Mul->getOperand(MulOp == 0);
-            if (Mul->getNumOperands() != 2) {
-              SmallVector<const SCEV *, 4> MulOps(Mul->op_begin(),
-                                                  Mul->op_begin()+MulOp);
-              MulOps.append(Mul->op_begin()+MulOp+1, Mul->op_end());
-              InnerMul1 = getMulExpr(MulOps, SCEV::FlagAnyWrap, Depth + 1);
-            }
-            const SCEV *InnerMul2 = OtherMul->getOperand(OMulOp == 0);
-            if (OtherMul->getNumOperands() != 2) {
-              SmallVector<const SCEV *, 4> MulOps(OtherMul->op_begin(),
-                                                  OtherMul->op_begin()+OMulOp);
-              MulOps.append(OtherMul->op_begin()+OMulOp+1, OtherMul->op_end());
-              InnerMul2 = getMulExpr(MulOps, SCEV::FlagAnyWrap, Depth + 1);
-            }
-            SmallVector<const SCEV *, 2> TwoOps = {InnerMul1, InnerMul2};
-            const SCEV *InnerMulSum =
-                getAddExpr(TwoOps, SCEV::FlagAnyWrap, Depth + 1);
-            const SCEV *OuterMul = getMulExpr(MulOpSCEV, InnerMulSum,
-                                              SCEV::FlagAnyWrap, Depth + 1);
-            if (Ops.size() == 2) return OuterMul;
-            Ops.erase(Ops.begin()+Idx);
-            Ops.erase(Ops.begin()+OtherMulIdx-1);
-            Ops.push_back(OuterMul);
-            return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);
-          }
-      }
-    }
-  }
-
-  // If there are any add recurrences in the operands list, see if any other
-  // added values are loop invariant.  If so, we can fold them into the
-  // recurrence.
-  while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scAddRecExpr)
-    ++Idx;
-
-  // Scan over all recurrences, trying to fold loop invariants into them.
-  for (; Idx < Ops.size() && isa<SCEVAddRecExpr>(Ops[Idx]); ++Idx) {
-    // Scan all of the other operands to this add and add them to the vector if
-    // they are loop invariant w.r.t. the recurrence.
-    SmallVector<const SCEV *, 8> LIOps;
-    const SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]);
-    const Loop *AddRecLoop = AddRec->getLoop();
-    for (unsigned i = 0, e = Ops.size(); i != e; ++i)
-      if (isAvailableAtLoopEntry(Ops[i], AddRecLoop)) {
-        LIOps.push_back(Ops[i]);
-        Ops.erase(Ops.begin()+i);
-        --i; --e;
-      }
-
-    // If we found some loop invariants, fold them into the recurrence.
-    if (!LIOps.empty()) {
-      //  NLI + LI + {Start,+,Step}  -->  NLI + {LI+Start,+,Step}
-      LIOps.push_back(AddRec->getStart());
-
-      SmallVector<const SCEV *, 4> AddRecOps(AddRec->op_begin(),
-                                             AddRec->op_end());
-      // This follows from the fact that the no-wrap flags on the outer add
-      // expression are applicable on the 0th iteration, when the add recurrence
-      // will be equal to its start value.
-      AddRecOps[0] = getAddExpr(LIOps, Flags, Depth + 1);
-
-      // Build the new addrec. Propagate the NUW and NSW flags if both the
-      // outer add and the inner addrec are guaranteed to have no overflow.
-      // Always propagate NW.
-      Flags = AddRec->getNoWrapFlags(setFlags(Flags, SCEV::FlagNW));
-      const SCEV *NewRec = getAddRecExpr(AddRecOps, AddRecLoop, Flags);
-
-      // If all of the other operands were loop invariant, we are done.
-      if (Ops.size() == 1) return NewRec;
-
-      // Otherwise, add the folded AddRec by the non-invariant parts.
-      for (unsigned i = 0;; ++i)
-        if (Ops[i] == AddRec) {
-          Ops[i] = NewRec;
-          break;
-        }
-      return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);
-    }
-
-    // Okay, if there weren't any loop invariants to be folded, check to see if
-    // there are multiple AddRec's with the same loop induction variable being
-    // added together.  If so, we can fold them.
-    for (unsigned OtherIdx = Idx+1;
-         OtherIdx < Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);
-         ++OtherIdx) {
-      // We expect the AddRecExpr's to be sorted in reverse dominance order,
-      // so that the 1st found AddRecExpr is dominated by all others.
-      assert(DT.dominates(
-           cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()->getHeader(),
-           AddRec->getLoop()->getHeader()) &&
-        "AddRecExprs are not sorted in reverse dominance order?");
-      if (AddRecLoop == cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()) {
-        // Other + {A,+,B}<L> + {C,+,D}<L>  -->  Other + {A+C,+,B+D}<L>
-        SmallVector<const SCEV *, 4> AddRecOps(AddRec->op_begin(),
-                                               AddRec->op_end());
-        for (; OtherIdx != Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);
-             ++OtherIdx) {
-          const auto *OtherAddRec = cast<SCEVAddRecExpr>(Ops[OtherIdx]);
-          if (OtherAddRec->getLoop() == AddRecLoop) {
-            for (unsigned i = 0, e = OtherAddRec->getNumOperands();
-                 i != e; ++i) {
-              if (i >= AddRecOps.size()) {
-                AddRecOps.append(OtherAddRec->op_begin()+i,
-                                 OtherAddRec->op_end());
-                break;
-              }
-              SmallVector<const SCEV *, 2> TwoOps = {
-                  AddRecOps[i], OtherAddRec->getOperand(i)};
-              AddRecOps[i] = getAddExpr(TwoOps, SCEV::FlagAnyWrap, Depth + 1);
-            }
-            Ops.erase(Ops.begin() + OtherIdx); --OtherIdx;
-          }
-        }
-        // Step size has changed, so we cannot guarantee no self-wraparound.
-        Ops[Idx] = getAddRecExpr(AddRecOps, AddRecLoop, SCEV::FlagAnyWrap);
-        return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);
-      }
-    }
-
-    // Otherwise couldn't fold anything into this recurrence.  Move onto the
-    // next one.
-  }
-
-  // Okay, it looks like we really DO need an add expr.  Check to see if we
-  // already have one, otherwise create a new one.
-  return getOrCreateAddExpr(Ops, Flags);
-}
-
-const SCEV *
-ScalarEvolution::getOrCreateAddExpr(SmallVectorImpl<const SCEV *> &Ops,
-                                    SCEV::NoWrapFlags Flags) {
-  FoldingSetNodeID ID;
-  ID.AddInteger(scAddExpr);
-  for (const SCEV *Op : Ops)
-    ID.AddPointer(Op);
-  void *IP = nullptr;
-  SCEVAddExpr *S =
-      static_cast<SCEVAddExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP));
-  if (!S) {
-    const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size());
-    std::uninitialized_copy(Ops.begin(), Ops.end(), O);
-    S = new (SCEVAllocator)
-        SCEVAddExpr(ID.Intern(SCEVAllocator), O, Ops.size());
-    UniqueSCEVs.InsertNode(S, IP);
-    addToLoopUseLists(S);
-  }
-  S->setNoWrapFlags(Flags);
-  return S;
-}
-
-const SCEV *
-ScalarEvolution::getOrCreateAddRecExpr(SmallVectorImpl<const SCEV *> &Ops,
-                                       const Loop *L, SCEV::NoWrapFlags Flags) {
-  FoldingSetNodeID ID;
-  ID.AddInteger(scAddRecExpr);
-  for (unsigned i = 0, e = Ops.size(); i != e; ++i)
-    ID.AddPointer(Ops[i]);
-  ID.AddPointer(L);
-  void *IP = nullptr;
-  SCEVAddRecExpr *S =
-      static_cast<SCEVAddRecExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP));
-  if (!S) {
-    const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size());
-    std::uninitialized_copy(Ops.begin(), Ops.end(), O);
-    S = new (SCEVAllocator)
-        SCEVAddRecExpr(ID.Intern(SCEVAllocator), O, Ops.size(), L);
-    UniqueSCEVs.InsertNode(S, IP);
-    addToLoopUseLists(S);
-  }
-  S->setNoWrapFlags(Flags);
-  return S;
-}
-
-const SCEV *
-ScalarEvolution::getOrCreateMulExpr(SmallVectorImpl<const SCEV *> &Ops,
-                                    SCEV::NoWrapFlags Flags) {
-  FoldingSetNodeID ID;
-  ID.AddInteger(scMulExpr);
-  for (unsigned i = 0, e = Ops.size(); i != e; ++i)
-    ID.AddPointer(Ops[i]);
-  void *IP = nullptr;
-  SCEVMulExpr *S =
-    static_cast<SCEVMulExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP));
-  if (!S) {
-    const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size());
-    std::uninitialized_copy(Ops.begin(), Ops.end(), O);
-    S = new (SCEVAllocator) SCEVMulExpr(ID.Intern(SCEVAllocator),
-                                        O, Ops.size());
-    UniqueSCEVs.InsertNode(S, IP);
-    addToLoopUseLists(S);
-  }
-  S->setNoWrapFlags(Flags);
-  return S;
-}
-
-static uint64_t umul_ov(uint64_t i, uint64_t j, bool &Overflow) {
-  uint64_t k = i*j;
-  if (j > 1 && k / j != i) Overflow = true;
-  return k;
-}
-
-/// Compute the result of "n choose k", the binomial coefficient.  If an
-/// intermediate computation overflows, Overflow will be set and the return will
-/// be garbage. Overflow is not cleared on absence of overflow.
-static uint64_t Choose(uint64_t n, uint64_t k, bool &Overflow) {
-  // We use the multiplicative formula:
-  //     n(n-1)(n-2)...(n-(k-1)) / k(k-1)(k-2)...1 .
-  // At each iteration, we take the n-th term of the numeral and divide by the
-  // (k-n)th term of the denominator.  This division will always produce an
-  // integral result, and helps reduce the chance of overflow in the
-  // intermediate computations. However, we can still overflow even when the
-  // final result would fit.
-
-  if (n == 0 || n == k) return 1;
-  if (k > n) return 0;
-
-  if (k > n/2)
-    k = n-k;
-
-  uint64_t r = 1;
-  for (uint64_t i = 1; i <= k; ++i) {
-    r = umul_ov(r, n-(i-1), Overflow);
-    r /= i;
-  }
-  return r;
-}
-
-/// Determine if any of the operands in this SCEV are a constant or if
-/// any of the add or multiply expressions in this SCEV contain a constant.
-static bool containsConstantInAddMulChain(const SCEV *StartExpr) {
-  struct FindConstantInAddMulChain {
-    bool FoundConstant = false;
-
-    bool follow(const SCEV *S) {
-      FoundConstant |= isa<SCEVConstant>(S);
-      return isa<SCEVAddExpr>(S) || isa<SCEVMulExpr>(S);
-    }
-
-    bool isDone() const {
-      return FoundConstant;
-    }
-  };
-
-  FindConstantInAddMulChain F;
-  SCEVTraversal<FindConstantInAddMulChain> ST(F);
-  ST.visitAll(StartExpr);
-  return F.FoundConstant;
-}
-
-/// Get a canonical multiply expression, or something simpler if possible.
-const SCEV *ScalarEvolution::getMulExpr(SmallVectorImpl<const SCEV *> &Ops,
-                                        SCEV::NoWrapFlags Flags,
-                                        unsigned Depth) {
-  assert(Flags == maskFlags(Flags, SCEV::FlagNUW | SCEV::FlagNSW) &&
-         "only nuw or nsw allowed");
-  assert(!Ops.empty() && "Cannot get empty mul!");
-  if (Ops.size() == 1) return Ops[0];
-#ifndef NDEBUG
-  Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
-  for (unsigned i = 1, e = Ops.size(); i != e; ++i)
-    assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
-           "SCEVMulExpr operand types don't match!");
-#endif
-
-  // Sort by complexity, this groups all similar expression types together.
-  GroupByComplexity(Ops, &LI, DT);
-
-  Flags = StrengthenNoWrapFlags(this, scMulExpr, Ops, Flags);
-
-  // Limit recursion calls depth.
-  if (Depth > MaxArithDepth)
-    return getOrCreateMulExpr(Ops, Flags);
-
-  // If there are any constants, fold them together.
-  unsigned Idx = 0;
-  if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
-
-    if (Ops.size() == 2)
-      // C1*(C2+V) -> C1*C2 + C1*V
-      if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[1]))
-        // If any of Add's ops are Adds or Muls with a constant, apply this
-        // transformation as well.
-        //
-        // TODO: There are some cases where this transformation is not
-        // profitable; for example, Add = (C0 + X) * Y + Z.  Maybe the scope of
-        // this transformation should be narrowed down.
-        if (Add->getNumOperands() == 2 && containsConstantInAddMulChain(Add))
-          return getAddExpr(getMulExpr(LHSC, Add->getOperand(0),
-                                       SCEV::FlagAnyWrap, Depth + 1),
-                            getMulExpr(LHSC, Add->getOperand(1),
-                                       SCEV::FlagAnyWrap, Depth + 1),
-                            SCEV::FlagAnyWrap, Depth + 1);
-
-    ++Idx;
-    while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) {
-      // We found two constants, fold them together!
-      ConstantInt *Fold =
-          ConstantInt::get(getContext(), LHSC->getAPInt() * RHSC->getAPInt());
-      Ops[0] = getConstant(Fold);
-      Ops.erase(Ops.begin()+1);  // Erase the folded element
-      if (Ops.size() == 1) return Ops[0];
-      LHSC = cast<SCEVConstant>(Ops[0]);
-    }
-
-    // If we are left with a constant one being multiplied, strip it off.
-    if (cast<SCEVConstant>(Ops[0])->getValue()->isOne()) {
-      Ops.erase(Ops.begin());
-      --Idx;
-    } else if (cast<SCEVConstant>(Ops[0])->getValue()->isZero()) {
-      // If we have a multiply of zero, it will always be zero.
-      return Ops[0];
-    } else if (Ops[0]->isAllOnesValue()) {
-      // If we have a mul by -1 of an add, try distributing the -1 among the
-      // add operands.
-      if (Ops.size() == 2) {
-        if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[1])) {
-          SmallVector<const SCEV *, 4> NewOps;
-          bool AnyFolded = false;
-          for (const SCEV *AddOp : Add->operands()) {
-            const SCEV *Mul = getMulExpr(Ops[0], AddOp, SCEV::FlagAnyWrap,
-                                         Depth + 1);
-            if (!isa<SCEVMulExpr>(Mul)) AnyFolded = true;
-            NewOps.push_back(Mul);
-          }
-          if (AnyFolded)
-            return getAddExpr(NewOps, SCEV::FlagAnyWrap, Depth + 1);
-        } else if (const auto *AddRec = dyn_cast<SCEVAddRecExpr>(Ops[1])) {
-          // Negation preserves a recurrence's no self-wrap property.
-          SmallVector<const SCEV *, 4> Operands;
-          for (const SCEV *AddRecOp : AddRec->operands())
-            Operands.push_back(getMulExpr(Ops[0], AddRecOp, SCEV::FlagAnyWrap,
-                                          Depth + 1));
-
-          return getAddRecExpr(Operands, AddRec->getLoop(),
-                               AddRec->getNoWrapFlags(SCEV::FlagNW));
-        }
-      }
-    }
-
-    if (Ops.size() == 1)
-      return Ops[0];
-  }
-
-  // Skip over the add expression until we get to a multiply.
-  while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scMulExpr)
-    ++Idx;
-
-  // If there are mul operands inline them all into this expression.
-  if (Idx < Ops.size()) {
-    bool DeletedMul = false;
-    while (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(Ops[Idx])) {
-      if (Ops.size() > MulOpsInlineThreshold)
-        break;
-      // If we have an mul, expand the mul operands onto the end of the
-      // operands list.
-      Ops.erase(Ops.begin()+Idx);
-      Ops.append(Mul->op_begin(), Mul->op_end());
-      DeletedMul = true;
-    }
-
-    // If we deleted at least one mul, we added operands to the end of the
-    // list, and they are not necessarily sorted.  Recurse to resort and
-    // resimplify any operands we just acquired.
-    if (DeletedMul)
-      return getMulExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);
-  }
-
-  // If there are any add recurrences in the operands list, see if any other
-  // added values are loop invariant.  If so, we can fold them into the
-  // recurrence.
-  while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scAddRecExpr)
-    ++Idx;
-
-  // Scan over all recurrences, trying to fold loop invariants into them.
-  for (; Idx < Ops.size() && isa<SCEVAddRecExpr>(Ops[Idx]); ++Idx) {
-    // Scan all of the other operands to this mul and add them to the vector
-    // if they are loop invariant w.r.t. the recurrence.
-    SmallVector<const SCEV *, 8> LIOps;
-    const SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]);
-    const Loop *AddRecLoop = AddRec->getLoop();
-    for (unsigned i = 0, e = Ops.size(); i != e; ++i)
-      if (isAvailableAtLoopEntry(Ops[i], AddRecLoop)) {
-        LIOps.push_back(Ops[i]);
-        Ops.erase(Ops.begin()+i);
-        --i; --e;
-      }
-
-    // If we found some loop invariants, fold them into the recurrence.
-    if (!LIOps.empty()) {
-      //  NLI * LI * {Start,+,Step}  -->  NLI * {LI*Start,+,LI*Step}
-      SmallVector<const SCEV *, 4> NewOps;
-      NewOps.reserve(AddRec->getNumOperands());
-      const SCEV *Scale = getMulExpr(LIOps, SCEV::FlagAnyWrap, Depth + 1);
-      for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i)
-        NewOps.push_back(getMulExpr(Scale, AddRec->getOperand(i),
-                                    SCEV::FlagAnyWrap, Depth + 1));
-
-      // Build the new addrec. Propagate the NUW and NSW flags if both the
-      // outer mul and the inner addrec are guaranteed to have no overflow.
-      //
-      // No self-wrap cannot be guaranteed after changing the step size, but
-      // will be inferred if either NUW or NSW is true.
-      Flags = AddRec->getNoWrapFlags(clearFlags(Flags, SCEV::FlagNW));
-      const SCEV *NewRec = getAddRecExpr(NewOps, AddRecLoop, Flags);
-
-      // If all of the other operands were loop invariant, we are done.
-      if (Ops.size() == 1) return NewRec;
-
-      // Otherwise, multiply the folded AddRec by the non-invariant parts.
-      for (unsigned i = 0;; ++i)
-        if (Ops[i] == AddRec) {
-          Ops[i] = NewRec;
-          break;
-        }
-      return getMulExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);
-    }
-
-    // Okay, if there weren't any loop invariants to be folded, check to see
-    // if there are multiple AddRec's with the same loop induction variable
-    // being multiplied together.  If so, we can fold them.
-
-    // {A1,+,A2,+,...,+,An}<L> * {B1,+,B2,+,...,+,Bn}<L>
-    // = {x=1 in [ sum y=x..2x [ sum z=max(y-x, y-n)..min(x,n) [
-    //       choose(x, 2x)*choose(2x-y, x-z)*A_{y-z}*B_z
-    //   ]]],+,...up to x=2n}.
-    // Note that the arguments to choose() are always integers with values
-    // known at compile time, never SCEV objects.
-    //
-    // The implementation avoids pointless extra computations when the two
-    // addrec's are of different length (mathematically, it's equivalent to
-    // an infinite stream of zeros on the right).
-    bool OpsModified = false;
-    for (unsigned OtherIdx = Idx+1;
-         OtherIdx != Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);
-         ++OtherIdx) {
-      const SCEVAddRecExpr *OtherAddRec =
-        dyn_cast<SCEVAddRecExpr>(Ops[OtherIdx]);
-      if (!OtherAddRec || OtherAddRec->getLoop() != AddRecLoop)
-        continue;
-
-      // Limit max number of arguments to avoid creation of unreasonably big
-      // SCEVAddRecs with very complex operands.
-      if (AddRec->getNumOperands() + OtherAddRec->getNumOperands() - 1 >
-          MaxAddRecSize)
-        continue;
-
-      bool Overflow = false;
-      Type *Ty = AddRec->getType();
-      bool LargerThan64Bits = getTypeSizeInBits(Ty) > 64;
-      SmallVector<const SCEV*, 7> AddRecOps;
-      for (int x = 0, xe = AddRec->getNumOperands() +
-             OtherAddRec->getNumOperands() - 1; x != xe && !Overflow; ++x) {
-        SmallVector <const SCEV *, 7> SumOps;
-        for (int y = x, ye = 2*x+1; y != ye && !Overflow; ++y) {
-          uint64_t Coeff1 = Choose(x, 2*x - y, Overflow);
-          for (int z = std::max(y-x, y-(int)AddRec->getNumOperands()+1),
-                 ze = std::min(x+1, (int)OtherAddRec->getNumOperands());
-               z < ze && !Overflow; ++z) {
-            uint64_t Coeff2 = Choose(2*x - y, x-z, Overflow);
-            uint64_t Coeff;
-            if (LargerThan64Bits)
-              Coeff = umul_ov(Coeff1, Coeff2, Overflow);
-            else
-              Coeff = Coeff1*Coeff2;
-            const SCEV *CoeffTerm = getConstant(Ty, Coeff);
-            const SCEV *Term1 = AddRec->getOperand(y-z);
-            const SCEV *Term2 = OtherAddRec->getOperand(z);
-            SumOps.push_back(getMulExpr(CoeffTerm, Term1, Term2,
-                                        SCEV::FlagAnyWrap, Depth + 1));
-          }
-        }
-        if (SumOps.empty())
-          SumOps.push_back(getZero(Ty));
-        AddRecOps.push_back(getAddExpr(SumOps, SCEV::FlagAnyWrap, Depth + 1));
-      }
-      if (!Overflow) {
-        const SCEV *NewAddRec = getAddRecExpr(AddRecOps, AddRec->getLoop(),
-                                              SCEV::FlagAnyWrap);
-        if (Ops.size() == 2) return NewAddRec;
-        Ops[Idx] = NewAddRec;
-        Ops.erase(Ops.begin() + OtherIdx); --OtherIdx;
-        OpsModified = true;
-        AddRec = dyn_cast<SCEVAddRecExpr>(NewAddRec);
-        if (!AddRec)
-          break;
-      }
-    }
-    if (OpsModified)
-      return getMulExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);
-
-    // Otherwise couldn't fold anything into this recurrence.  Move onto the
-    // next one.
-  }
-
-  // Okay, it looks like we really DO need an mul expr.  Check to see if we
-  // already have one, otherwise create a new one.
-  return getOrCreateMulExpr(Ops, Flags);
-}
-
-/// Represents an unsigned remainder expression based on unsigned division.
-const SCEV *ScalarEvolution::getURemExpr(const SCEV *LHS,
-                                         const SCEV *RHS) {
-  assert(getEffectiveSCEVType(LHS->getType()) ==
-         getEffectiveSCEVType(RHS->getType()) &&
-         "SCEVURemExpr operand types don't match!");
-
-  // Short-circuit easy cases
-  if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) {
-    // If constant is one, the result is trivial
-    if (RHSC->getValue()->isOne())
-      return getZero(LHS->getType()); // X urem 1 --> 0
-
-    // If constant is a power of two, fold into a zext(trunc(LHS)).
-    if (RHSC->getAPInt().isPowerOf2()) {
-      Type *FullTy = LHS->getType();
-      Type *TruncTy =
-          IntegerType::get(getContext(), RHSC->getAPInt().logBase2());
-      return getZeroExtendExpr(getTruncateExpr(LHS, TruncTy), FullTy);
-    }
-  }
-
-  // Fallback to %a == %x urem %y == %x -<nuw> ((%x udiv %y) *<nuw> %y)
-  const SCEV *UDiv = getUDivExpr(LHS, RHS);
-  const SCEV *Mult = getMulExpr(UDiv, RHS, SCEV::FlagNUW);
-  return getMinusSCEV(LHS, Mult, SCEV::FlagNUW);
-}
-
-/// Get a canonical unsigned division expression, or something simpler if
-/// possible.
-const SCEV *ScalarEvolution::getUDivExpr(const SCEV *LHS,
-                                         const SCEV *RHS) {
-  assert(getEffectiveSCEVType(LHS->getType()) ==
-         getEffectiveSCEVType(RHS->getType()) &&
-         "SCEVUDivExpr operand types don't match!");
-
-  if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) {
-    if (RHSC->getValue()->isOne())
-      return LHS;                               // X udiv 1 --> x
-    // If the denominator is zero, the result of the udiv is undefined. Don't
-    // try to analyze it, because the resolution chosen here may differ from
-    // the resolution chosen in other parts of the compiler.
-    if (!RHSC->getValue()->isZero()) {
-      // Determine if the division can be folded into the operands of
-      // its operands.
-      // TODO: Generalize this to non-constants by using known-bits information.
-      Type *Ty = LHS->getType();
-      unsigned LZ = RHSC->getAPInt().countLeadingZeros();
-      unsigned MaxShiftAmt = getTypeSizeInBits(Ty) - LZ - 1;
-      // For non-power-of-two values, effectively round the value up to the
-      // nearest power of two.
-      if (!RHSC->getAPInt().isPowerOf2())
-        ++MaxShiftAmt;
-      IntegerType *ExtTy =
-        IntegerType::get(getContext(), getTypeSizeInBits(Ty) + MaxShiftAmt);
-      if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(LHS))
-        if (const SCEVConstant *Step =
-            dyn_cast<SCEVConstant>(AR->getStepRecurrence(*this))) {
-          // {X,+,N}/C --> {X/C,+,N/C} if safe and N/C can be folded.
-          const APInt &StepInt = Step->getAPInt();
-          const APInt &DivInt = RHSC->getAPInt();
-          if (!StepInt.urem(DivInt) &&
-              getZeroExtendExpr(AR, ExtTy) ==
-              getAddRecExpr(getZeroExtendExpr(AR->getStart(), ExtTy),
-                            getZeroExtendExpr(Step, ExtTy),
-                            AR->getLoop(), SCEV::FlagAnyWrap)) {
-            SmallVector<const SCEV *, 4> Operands;
-            for (const SCEV *Op : AR->operands())
-              Operands.push_back(getUDivExpr(Op, RHS));
-            return getAddRecExpr(Operands, AR->getLoop(), SCEV::FlagNW);
-          }
-          /// Get a canonical UDivExpr for a recurrence.
-          /// {X,+,N}/C => {Y,+,N}/C where Y=X-(X%N). Safe when C%N=0.
-          // We can currently only fold X%N if X is constant.
-          const SCEVConstant *StartC = dyn_cast<SCEVConstant>(AR->getStart());
-          if (StartC && !DivInt.urem(StepInt) &&
-              getZeroExtendExpr(AR, ExtTy) ==
-              getAddRecExpr(getZeroExtendExpr(AR->getStart(), ExtTy),
-                            getZeroExtendExpr(Step, ExtTy),
-                            AR->getLoop(), SCEV::FlagAnyWrap)) {
-            const APInt &StartInt = StartC->getAPInt();
-            const APInt &StartRem = StartInt.urem(StepInt);
-            if (StartRem != 0)
-              LHS = getAddRecExpr(getConstant(StartInt - StartRem), Step,
-                                  AR->getLoop(), SCEV::FlagNW);
-          }
-        }
-      // (A*B)/C --> A*(B/C) if safe and B/C can be folded.
-      if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(LHS)) {
-        SmallVector<const SCEV *, 4> Operands;
-        for (const SCEV *Op : M->operands())
-          Operands.push_back(getZeroExtendExpr(Op, ExtTy));
-        if (getZeroExtendExpr(M, ExtTy) == getMulExpr(Operands))
-          // Find an operand that's safely divisible.
-          for (unsigned i = 0, e = M->getNumOperands(); i != e; ++i) {
-            const SCEV *Op = M->getOperand(i);
-            const SCEV *Div = getUDivExpr(Op, RHSC);
-            if (!isa<SCEVUDivExpr>(Div) && getMulExpr(Div, RHSC) == Op) {
-              Operands = SmallVector<const SCEV *, 4>(M->op_begin(),
-                                                      M->op_end());
-              Operands[i] = Div;
-              return getMulExpr(Operands);
-            }
-          }
-      }
-
-      // (A/B)/C --> A/(B*C) if safe and B*C can be folded.
-      if (const SCEVUDivExpr *OtherDiv = dyn_cast<SCEVUDivExpr>(LHS)) {
-        if (auto *DivisorConstant =
-                dyn_cast<SCEVConstant>(OtherDiv->getRHS())) {
-          bool Overflow = false;
-          APInt NewRHS =
-              DivisorConstant->getAPInt().umul_ov(RHSC->getAPInt(), Overflow);
-          if (Overflow) {
-            return getConstant(RHSC->getType(), 0, false);
-          }
-          return getUDivExpr(OtherDiv->getLHS(), getConstant(NewRHS));
-        }
-      }
-
-      // (A+B)/C --> (A/C + B/C) if safe and A/C and B/C can be folded.
-      if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(LHS)) {
-        SmallVector<const SCEV *, 4> Operands;
-        for (const SCEV *Op : A->operands())
-          Operands.push_back(getZeroExtendExpr(Op, ExtTy));
-        if (getZeroExtendExpr(A, ExtTy) == getAddExpr(Operands)) {
-          Operands.clear();
-          for (unsigned i = 0, e = A->getNumOperands(); i != e; ++i) {
-            const SCEV *Op = getUDivExpr(A->getOperand(i), RHS);
-            if (isa<SCEVUDivExpr>(Op) ||
-                getMulExpr(Op, RHS) != A->getOperand(i))
-              break;
-            Operands.push_back(Op);
-          }
-          if (Operands.size() == A->getNumOperands())
-            return getAddExpr(Operands);
-        }
-      }
-
-      // Fold if both operands are constant.
-      if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(LHS)) {
-        Constant *LHSCV = LHSC->getValue();
-        Constant *RHSCV = RHSC->getValue();
-        return getConstant(cast<ConstantInt>(ConstantExpr::getUDiv(LHSCV,
-                                                                   RHSCV)));
-      }
-    }
-  }
-
-  FoldingSetNodeID ID;
-  ID.AddInteger(scUDivExpr);
-  ID.AddPointer(LHS);
-  ID.AddPointer(RHS);
-  void *IP = nullptr;
-  if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
-  SCEV *S = new (SCEVAllocator) SCEVUDivExpr(ID.Intern(SCEVAllocator),
-                                             LHS, RHS);
-  UniqueSCEVs.InsertNode(S, IP);
-  addToLoopUseLists(S);
-  return S;
-}
-
-static const APInt gcd(const SCEVConstant *C1, const SCEVConstant *C2) {
-  APInt A = C1->getAPInt().abs();
-  APInt B = C2->getAPInt().abs();
-  uint32_t ABW = A.getBitWidth();
-  uint32_t BBW = B.getBitWidth();
-
-  if (ABW > BBW)
-    B = B.zext(ABW);
-  else if (ABW < BBW)
-    A = A.zext(BBW);
-
-  return APIntOps::GreatestCommonDivisor(std::move(A), std::move(B));
-}
-
-/// Get a canonical unsigned division expression, or something simpler if
-/// possible. There is no representation for an exact udiv in SCEV IR, but we
-/// can attempt to remove factors from the LHS and RHS.  We can't do this when
-/// it's not exact because the udiv may be clearing bits.
-const SCEV *ScalarEvolution::getUDivExactExpr(const SCEV *LHS,
-                                              const SCEV *RHS) {
-  // TODO: we could try to find factors in all sorts of things, but for now we
-  // just deal with u/exact (multiply, constant). See SCEVDivision towards the
-  // end of this file for inspiration.
-
-  const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(LHS);
-  if (!Mul || !Mul->hasNoUnsignedWrap())
-    return getUDivExpr(LHS, RHS);
-
-  if (const SCEVConstant *RHSCst = dyn_cast<SCEVConstant>(RHS)) {
-    // If the mulexpr multiplies by a constant, then that constant must be the
-    // first element of the mulexpr.
-    if (const auto *LHSCst = dyn_cast<SCEVConstant>(Mul->getOperand(0))) {
-      if (LHSCst == RHSCst) {
-        SmallVector<const SCEV *, 2> Operands;
-        Operands.append(Mul->op_begin() + 1, Mul->op_end());
-        return getMulExpr(Operands);
-      }
-
-      // We can't just assume that LHSCst divides RHSCst cleanly, it could be
-      // that there's a factor provided by one of the other terms. We need to
-      // check.
-      APInt Factor = gcd(LHSCst, RHSCst);
-      if (!Factor.isIntN(1)) {
-        LHSCst =
-            cast<SCEVConstant>(getConstant(LHSCst->getAPInt().udiv(Factor)));
-        RHSCst =
-            cast<SCEVConstant>(getConstant(RHSCst->getAPInt().udiv(Factor)));
-        SmallVector<const SCEV *, 2> Operands;
-        Operands.push_back(LHSCst);
-        Operands.append(Mul->op_begin() + 1, Mul->op_end());
-        LHS = getMulExpr(Operands);
-        RHS = RHSCst;
-        Mul = dyn_cast<SCEVMulExpr>(LHS);
-        if (!Mul)
-          return getUDivExactExpr(LHS, RHS);
-      }
-    }
-  }
-
-  for (int i = 0, e = Mul->getNumOperands(); i != e; ++i) {
-    if (Mul->getOperand(i) == RHS) {
-      SmallVector<const SCEV *, 2> Operands;
-      Operands.append(Mul->op_begin(), Mul->op_begin() + i);
-      Operands.append(Mul->op_begin() + i + 1, Mul->op_end());
-      return getMulExpr(Operands);
-    }
-  }
-
-  return getUDivExpr(LHS, RHS);
-}
-
-/// Get an add recurrence expression for the specified loop.  Simplify the
-/// expression as much as possible.
-const SCEV *ScalarEvolution::getAddRecExpr(const SCEV *Start, const SCEV *Step,
-                                           const Loop *L,
-                                           SCEV::NoWrapFlags Flags) {
-  SmallVector<const SCEV *, 4> Operands;
-  Operands.push_back(Start);
-  if (const SCEVAddRecExpr *StepChrec = dyn_cast<SCEVAddRecExpr>(Step))
-    if (StepChrec->getLoop() == L) {
-      Operands.append(StepChrec->op_begin(), StepChrec->op_end());
-      return getAddRecExpr(Operands, L, maskFlags(Flags, SCEV::FlagNW));
-    }
-
-  Operands.push_back(Step);
-  return getAddRecExpr(Operands, L, Flags);
-}
-
-/// Get an add recurrence expression for the specified loop.  Simplify the
-/// expression as much as possible.
-const SCEV *
-ScalarEvolution::getAddRecExpr(SmallVectorImpl<const SCEV *> &Operands,
-                               const Loop *L, SCEV::NoWrapFlags Flags) {
-  if (Operands.size() == 1) return Operands[0];
-#ifndef NDEBUG
-  Type *ETy = getEffectiveSCEVType(Operands[0]->getType());
-  for (unsigned i = 1, e = Operands.size(); i != e; ++i)
-    assert(getEffectiveSCEVType(Operands[i]->getType()) == ETy &&
-           "SCEVAddRecExpr operand types don't match!");
-  for (unsigned i = 0, e = Operands.size(); i != e; ++i)
-    assert(isLoopInvariant(Operands[i], L) &&
-           "SCEVAddRecExpr operand is not loop-invariant!");
-#endif
-
-  if (Operands.back()->isZero()) {
-    Operands.pop_back();
-    return getAddRecExpr(Operands, L, SCEV::FlagAnyWrap); // {X,+,0}  -->  X
-  }
-
-  // It's tempting to want to call getMaxBackedgeTakenCount count here and
-  // use that information to infer NUW and NSW flags. However, computing a
-  // BE count requires calling getAddRecExpr, so we may not yet have a
-  // meaningful BE count at this point (and if we don't, we'd be stuck
-  // with a SCEVCouldNotCompute as the cached BE count).
-
-  Flags = StrengthenNoWrapFlags(this, scAddRecExpr, Operands, Flags);
-
-  // Canonicalize nested AddRecs in by nesting them in order of loop depth.
-  if (const SCEVAddRecExpr *NestedAR = dyn_cast<SCEVAddRecExpr>(Operands[0])) {
-    const Loop *NestedLoop = NestedAR->getLoop();
-    if (L->contains(NestedLoop)
-            ? (L->getLoopDepth() < NestedLoop->getLoopDepth())
-            : (!NestedLoop->contains(L) &&
-               DT.dominates(L->getHeader(), NestedLoop->getHeader()))) {
-      SmallVector<const SCEV *, 4> NestedOperands(NestedAR->op_begin(),
-                                                  NestedAR->op_end());
-      Operands[0] = NestedAR->getStart();
-      // AddRecs require their operands be loop-invariant with respect to their
-      // loops. Don't perform this transformation if it would break this
-      // requirement.
-      bool AllInvariant = all_of(
-          Operands, [&](const SCEV *Op) { return isLoopInvariant(Op, L); });
-
-      if (AllInvariant) {
-        // Create a recurrence for the outer loop with the same step size.
-        //
-        // The outer recurrence keeps its NW flag but only keeps NUW/NSW if the
-        // inner recurrence has the same property.
-        SCEV::NoWrapFlags OuterFlags =
-          maskFlags(Flags, SCEV::FlagNW | NestedAR->getNoWrapFlags());
-
-        NestedOperands[0] = getAddRecExpr(Operands, L, OuterFlags);
-        AllInvariant = all_of(NestedOperands, [&](const SCEV *Op) {
-          return isLoopInvariant(Op, NestedLoop);
-        });
-
-        if (AllInvariant) {
-          // Ok, both add recurrences are valid after the transformation.
-          //
-          // The inner recurrence keeps its NW flag but only keeps NUW/NSW if
-          // the outer recurrence has the same property.
-          SCEV::NoWrapFlags InnerFlags =
-            maskFlags(NestedAR->getNoWrapFlags(), SCEV::FlagNW | Flags);
-          return getAddRecExpr(NestedOperands, NestedLoop, InnerFlags);
-        }
-      }
-      // Reset Operands to its original state.
-      Operands[0] = NestedAR;
-    }
-  }
-
-  // Okay, it looks like we really DO need an addrec expr.  Check to see if we
-  // already have one, otherwise create a new one.
-  return getOrCreateAddRecExpr(Operands, L, Flags);
-}
-
-const SCEV *
-ScalarEvolution::getGEPExpr(GEPOperator *GEP,
-                            const SmallVectorImpl<const SCEV *> &IndexExprs) {
-  const SCEV *BaseExpr = getSCEV(GEP->getPointerOperand());
-  // getSCEV(Base)->getType() has the same address space as Base->getType()
-  // because SCEV::getType() preserves the address space.
-  Type *IntPtrTy = getEffectiveSCEVType(BaseExpr->getType());
-  // FIXME(PR23527): Don't blindly transfer the inbounds flag from the GEP
-  // instruction to its SCEV, because the Instruction may be guarded by control
-  // flow and the no-overflow bits may not be valid for the expression in any
-  // context. This can be fixed similarly to how these flags are handled for
-  // adds.
-  SCEV::NoWrapFlags Wrap = GEP->isInBounds() ? SCEV::FlagNSW
-                                             : SCEV::FlagAnyWrap;
-
-  const SCEV *TotalOffset = getZero(IntPtrTy);
-  // The array size is unimportant. The first thing we do on CurTy is getting
-  // its element type.
-  Type *CurTy = ArrayType::get(GEP->getSourceElementType(), 0);
-  for (const SCEV *IndexExpr : IndexExprs) {
-    // Compute the (potentially symbolic) offset in bytes for this index.
-    if (StructType *STy = dyn_cast<StructType>(CurTy)) {
-      // For a struct, add the member offset.
-      ConstantInt *Index = cast<SCEVConstant>(IndexExpr)->getValue();
-      unsigned FieldNo = Index->getZExtValue();
-      const SCEV *FieldOffset = getOffsetOfExpr(IntPtrTy, STy, FieldNo);
-
-      // Add the field offset to the running total offset.
-      TotalOffset = getAddExpr(TotalOffset, FieldOffset);
-
-      // Update CurTy to the type of the field at Index.
-      CurTy = STy->getTypeAtIndex(Index);
-    } else {
-      // Update CurTy to its element type.
-      CurTy = cast<SequentialType>(CurTy)->getElementType();
-      // For an array, add the element offset, explicitly scaled.
-      const SCEV *ElementSize = getSizeOfExpr(IntPtrTy, CurTy);
-      // Getelementptr indices are signed.
-      IndexExpr = getTruncateOrSignExtend(IndexExpr, IntPtrTy);
-
-      // Multiply the index by the element size to compute the element offset.
-      const SCEV *LocalOffset = getMulExpr(IndexExpr, ElementSize, Wrap);
-
-      // Add the element offset to the running total offset.
-      TotalOffset = getAddExpr(TotalOffset, LocalOffset);
-    }
-  }
-
-  // Add the total offset from all the GEP indices to the base.
-  return getAddExpr(BaseExpr, TotalOffset, Wrap);
-}
-
-const SCEV *ScalarEvolution::getSMaxExpr(const SCEV *LHS,
-                                         const SCEV *RHS) {
-  SmallVector<const SCEV *, 2> Ops = {LHS, RHS};
-  return getSMaxExpr(Ops);
-}
-
-const SCEV *
-ScalarEvolution::getSMaxExpr(SmallVectorImpl<const SCEV *> &Ops) {
-  assert(!Ops.empty() && "Cannot get empty smax!");
-  if (Ops.size() == 1) return Ops[0];
-#ifndef NDEBUG
-  Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
-  for (unsigned i = 1, e = Ops.size(); i != e; ++i)
-    assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
-           "SCEVSMaxExpr operand types don't match!");
-#endif
-
-  // Sort by complexity, this groups all similar expression types together.
-  GroupByComplexity(Ops, &LI, DT);
-
-  // If there are any constants, fold them together.
-  unsigned Idx = 0;
-  if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
-    ++Idx;
-    assert(Idx < Ops.size());
-    while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) {
-      // We found two constants, fold them together!
-      ConstantInt *Fold = ConstantInt::get(
-          getContext(), APIntOps::smax(LHSC->getAPInt(), RHSC->getAPInt()));
-      Ops[0] = getConstant(Fold);
-      Ops.erase(Ops.begin()+1);  // Erase the folded element
-      if (Ops.size() == 1) return Ops[0];
-      LHSC = cast<SCEVConstant>(Ops[0]);
-    }
-
-    // If we are left with a constant minimum-int, strip it off.
-    if (cast<SCEVConstant>(Ops[0])->getValue()->isMinValue(true)) {
-      Ops.erase(Ops.begin());
-      --Idx;
-    } else if (cast<SCEVConstant>(Ops[0])->getValue()->isMaxValue(true)) {
-      // If we have an smax with a constant maximum-int, it will always be
-      // maximum-int.
-      return Ops[0];
-    }
-
-    if (Ops.size() == 1) return Ops[0];
-  }
-
-  // Find the first SMax
-  while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scSMaxExpr)
-    ++Idx;
-
-  // Check to see if one of the operands is an SMax. If so, expand its operands
-  // onto our operand list, and recurse to simplify.
-  if (Idx < Ops.size()) {
-    bool DeletedSMax = false;
-    while (const SCEVSMaxExpr *SMax = dyn_cast<SCEVSMaxExpr>(Ops[Idx])) {
-      Ops.erase(Ops.begin()+Idx);
-      Ops.append(SMax->op_begin(), SMax->op_end());
-      DeletedSMax = true;
-    }
-
-    if (DeletedSMax)
-      return getSMaxExpr(Ops);
-  }
-
-  // Okay, check to see if the same value occurs in the operand list twice.  If
-  // so, delete one.  Since we sorted the list, these values are required to
-  // be adjacent.
-  for (unsigned i = 0, e = Ops.size()-1; i != e; ++i)
-    //  X smax Y smax Y  -->  X smax Y
-    //  X smax Y         -->  X, if X is always greater than Y
-    if (Ops[i] == Ops[i+1] ||
-        isKnownPredicate(ICmpInst::ICMP_SGE, Ops[i], Ops[i+1])) {
-      Ops.erase(Ops.begin()+i+1, Ops.begin()+i+2);
-      --i; --e;
-    } else if (isKnownPredicate(ICmpInst::ICMP_SLE, Ops[i], Ops[i+1])) {
-      Ops.erase(Ops.begin()+i, Ops.begin()+i+1);
-      --i; --e;
-    }
-
-  if (Ops.size() == 1) return Ops[0];
-
-  assert(!Ops.empty() && "Reduced smax down to nothing!");
-
-  // Okay, it looks like we really DO need an smax expr.  Check to see if we
-  // already have one, otherwise create a new one.
-  FoldingSetNodeID ID;
-  ID.AddInteger(scSMaxExpr);
-  for (unsigned i = 0, e = Ops.size(); i != e; ++i)
-    ID.AddPointer(Ops[i]);
-  void *IP = nullptr;
-  if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
-  const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size());
-  std::uninitialized_copy(Ops.begin(), Ops.end(), O);
-  SCEV *S = new (SCEVAllocator) SCEVSMaxExpr(ID.Intern(SCEVAllocator),
-                                             O, Ops.size());
-  UniqueSCEVs.InsertNode(S, IP);
-  addToLoopUseLists(S);
-  return S;
-}
-
-const SCEV *ScalarEvolution::getUMaxExpr(const SCEV *LHS,
-                                         const SCEV *RHS) {
-  SmallVector<const SCEV *, 2> Ops = {LHS, RHS};
-  return getUMaxExpr(Ops);
-}
-
-const SCEV *
-ScalarEvolution::getUMaxExpr(SmallVectorImpl<const SCEV *> &Ops) {
-  assert(!Ops.empty() && "Cannot get empty umax!");
-  if (Ops.size() == 1) return Ops[0];
-#ifndef NDEBUG
-  Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
-  for (unsigned i = 1, e = Ops.size(); i != e; ++i)
-    assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
-           "SCEVUMaxExpr operand types don't match!");
-#endif
-
-  // Sort by complexity, this groups all similar expression types together.
-  GroupByComplexity(Ops, &LI, DT);
-
-  // If there are any constants, fold them together.
-  unsigned Idx = 0;
-  if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
-    ++Idx;
-    assert(Idx < Ops.size());
-    while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) {
-      // We found two constants, fold them together!
-      ConstantInt *Fold = ConstantInt::get(
-          getContext(), APIntOps::umax(LHSC->getAPInt(), RHSC->getAPInt()));
-      Ops[0] = getConstant(Fold);
-      Ops.erase(Ops.begin()+1);  // Erase the folded element
-      if (Ops.size() == 1) return Ops[0];
-      LHSC = cast<SCEVConstant>(Ops[0]);
-    }
-
-    // If we are left with a constant minimum-int, strip it off.
-    if (cast<SCEVConstant>(Ops[0])->getValue()->isMinValue(false)) {
-      Ops.erase(Ops.begin());
-      --Idx;
-    } else if (cast<SCEVConstant>(Ops[0])->getValue()->isMaxValue(false)) {
-      // If we have an umax with a constant maximum-int, it will always be
-      // maximum-int.
-      return Ops[0];
-    }
-
-    if (Ops.size() == 1) return Ops[0];
-  }
-
-  // Find the first UMax
-  while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scUMaxExpr)
-    ++Idx;
-
-  // Check to see if one of the operands is a UMax. If so, expand its operands
-  // onto our operand list, and recurse to simplify.
-  if (Idx < Ops.size()) {
-    bool DeletedUMax = false;
-    while (const SCEVUMaxExpr *UMax = dyn_cast<SCEVUMaxExpr>(Ops[Idx])) {
-      Ops.erase(Ops.begin()+Idx);
-      Ops.append(UMax->op_begin(), UMax->op_end());
-      DeletedUMax = true;
-    }
-
-    if (DeletedUMax)
-      return getUMaxExpr(Ops);
-  }
-
-  // Okay, check to see if the same value occurs in the operand list twice.  If
-  // so, delete one.  Since we sorted the list, these values are required to
-  // be adjacent.
-  for (unsigned i = 0, e = Ops.size()-1; i != e; ++i)
-    //  X umax Y umax Y  -->  X umax Y
-    //  X umax Y         -->  X, if X is always greater than Y
-    if (Ops[i] == Ops[i + 1] || isKnownViaNonRecursiveReasoning(
-                                    ICmpInst::ICMP_UGE, Ops[i], Ops[i + 1])) {
-      Ops.erase(Ops.begin() + i + 1, Ops.begin() + i + 2);
-      --i; --e;
-    } else if (isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_ULE, Ops[i],
-                                               Ops[i + 1])) {
-      Ops.erase(Ops.begin() + i, Ops.begin() + i + 1);
-      --i; --e;
-    }
-
-  if (Ops.size() == 1) return Ops[0];
-
-  assert(!Ops.empty() && "Reduced umax down to nothing!");
-
-  // Okay, it looks like we really DO need a umax expr.  Check to see if we
-  // already have one, otherwise create a new one.
-  FoldingSetNodeID ID;
-  ID.AddInteger(scUMaxExpr);
-  for (unsigned i = 0, e = Ops.size(); i != e; ++i)
-    ID.AddPointer(Ops[i]);
-  void *IP = nullptr;
-  if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
-  const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size());
-  std::uninitialized_copy(Ops.begin(), Ops.end(), O);
-  SCEV *S = new (SCEVAllocator) SCEVUMaxExpr(ID.Intern(SCEVAllocator),
-                                             O, Ops.size());
-  UniqueSCEVs.InsertNode(S, IP);
-  addToLoopUseLists(S);
-  return S;
-}
-
-const SCEV *ScalarEvolution::getSMinExpr(const SCEV *LHS,
-                                         const SCEV *RHS) {
-  SmallVector<const SCEV *, 2> Ops = { LHS, RHS };
-  return getSMinExpr(Ops);
-}
-
-const SCEV *ScalarEvolution::getSMinExpr(SmallVectorImpl<const SCEV *> &Ops) {
-  // ~smax(~x, ~y, ~z) == smin(x, y, z).
-  SmallVector<const SCEV *, 2> NotOps;
-  for (auto *S : Ops)
-    NotOps.push_back(getNotSCEV(S));
-  return getNotSCEV(getSMaxExpr(NotOps));
-}
-
-const SCEV *ScalarEvolution::getUMinExpr(const SCEV *LHS,
-                                         const SCEV *RHS) {
-  SmallVector<const SCEV *, 2> Ops = { LHS, RHS };
-  return getUMinExpr(Ops);
-}
-
-const SCEV *ScalarEvolution::getUMinExpr(SmallVectorImpl<const SCEV *> &Ops) {
-  assert(!Ops.empty() && "At least one operand must be!");
-  // Trivial case.
-  if (Ops.size() == 1)
-    return Ops[0];
-
-  // ~umax(~x, ~y, ~z) == umin(x, y, z).
-  SmallVector<const SCEV *, 2> NotOps;
-  for (auto *S : Ops)
-    NotOps.push_back(getNotSCEV(S));
-  return getNotSCEV(getUMaxExpr(NotOps));
-}
-
-const SCEV *ScalarEvolution::getSizeOfExpr(Type *IntTy, Type *AllocTy) {
-  // We can bypass creating a target-independent
-  // constant expression and then folding it back into a ConstantInt.
-  // This is just a compile-time optimization.
-  return getConstant(IntTy, getDataLayout().getTypeAllocSize(AllocTy));
-}
-
-const SCEV *ScalarEvolution::getOffsetOfExpr(Type *IntTy,
-                                             StructType *STy,
-                                             unsigned FieldNo) {
-  // We can bypass creating a target-independent
-  // constant expression and then folding it back into a ConstantInt.
-  // This is just a compile-time optimization.
-  return getConstant(
-      IntTy, getDataLayout().getStructLayout(STy)->getElementOffset(FieldNo));
-}
-
-const SCEV *ScalarEvolution::getUnknown(Value *V) {
-  // Don't attempt to do anything other than create a SCEVUnknown object
-  // here.  createSCEV only calls getUnknown after checking for all other
-  // interesting possibilities, and any other code that calls getUnknown
-  // is doing so in order to hide a value from SCEV canonicalization.
-
-  FoldingSetNodeID ID;
-  ID.AddInteger(scUnknown);
-  ID.AddPointer(V);
-  void *IP = nullptr;
-  if (SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) {
-    assert(cast<SCEVUnknown>(S)->getValue() == V &&
-           "Stale SCEVUnknown in uniquing map!");
-    return S;
-  }
-  SCEV *S = new (SCEVAllocator) SCEVUnknown(ID.Intern(SCEVAllocator), V, this,
-                                            FirstUnknown);
-  FirstUnknown = cast<SCEVUnknown>(S);
-  UniqueSCEVs.InsertNode(S, IP);
-  return S;
-}
-
-//===----------------------------------------------------------------------===//
-//            Basic SCEV Analysis and PHI Idiom Recognition Code
-//
-
-/// Test if values of the given type are analyzable within the SCEV
-/// framework. This primarily includes integer types, and it can optionally
-/// include pointer types if the ScalarEvolution class has access to
-/// target-specific information.
-bool ScalarEvolution::isSCEVable(Type *Ty) const {
-  // Integers and pointers are always SCEVable.
-  return Ty->isIntOrPtrTy();
-}
-
-/// Return the size in bits of the specified type, for which isSCEVable must
-/// return true.
-uint64_t ScalarEvolution::getTypeSizeInBits(Type *Ty) const {
-  assert(isSCEVable(Ty) && "Type is not SCEVable!");
-  if (Ty->isPointerTy())
-    return getDataLayout().getIndexTypeSizeInBits(Ty);
-  return getDataLayout().getTypeSizeInBits(Ty);
-}
-
-/// Return a type with the same bitwidth as the given type and which represents
-/// how SCEV will treat the given type, for which isSCEVable must return
-/// true. For pointer types, this is the pointer-sized integer type.
-Type *ScalarEvolution::getEffectiveSCEVType(Type *Ty) const {
-  assert(isSCEVable(Ty) && "Type is not SCEVable!");
-
-  if (Ty->isIntegerTy())
-    return Ty;
-
-  // The only other support type is pointer.
-  assert(Ty->isPointerTy() && "Unexpected non-pointer non-integer type!");
-  return getDataLayout().getIntPtrType(Ty);
-}
-
-Type *ScalarEvolution::getWiderType(Type *T1, Type *T2) const {
-  return  getTypeSizeInBits(T1) >= getTypeSizeInBits(T2) ? T1 : T2;
-}
-
-const SCEV *ScalarEvolution::getCouldNotCompute() {
-  return CouldNotCompute.get();
-}
-
-bool ScalarEvolution::checkValidity(const SCEV *S) const {
-  bool ContainsNulls = SCEVExprContains(S, [](const SCEV *S) {
-    auto *SU = dyn_cast<SCEVUnknown>(S);
-    return SU && SU->getValue() == nullptr;
-  });
-
-  return !ContainsNulls;
-}
-
-bool ScalarEvolution::containsAddRecurrence(const SCEV *S) {
-  HasRecMapType::iterator I = HasRecMap.find(S);
-  if (I != HasRecMap.end())
-    return I->second;
-
-  bool FoundAddRec = SCEVExprContains(S, isa<SCEVAddRecExpr, const SCEV *>);
-  HasRecMap.insert({S, FoundAddRec});
-  return FoundAddRec;
-}
-
-/// Try to split a SCEVAddExpr into a pair of {SCEV, ConstantInt}.
-/// If \p S is a SCEVAddExpr and is composed of a sub SCEV S' and an
-/// offset I, then return {S', I}, else return {\p S, nullptr}.
-static std::pair<const SCEV *, ConstantInt *> splitAddExpr(const SCEV *S) {
-  const auto *Add = dyn_cast<SCEVAddExpr>(S);
-  if (!Add)
-    return {S, nullptr};
-
-  if (Add->getNumOperands() != 2)
-    return {S, nullptr};
-
-  auto *ConstOp = dyn_cast<SCEVConstant>(Add->getOperand(0));
-  if (!ConstOp)
-    return {S, nullptr};
-
-  return {Add->getOperand(1), ConstOp->getValue()};
-}
-
-/// Return the ValueOffsetPair set for \p S. \p S can be represented
-/// by the value and offset from any ValueOffsetPair in the set.
-SetVector<ScalarEvolution::ValueOffsetPair> *
-ScalarEvolution::getSCEVValues(const SCEV *S) {
-  ExprValueMapType::iterator SI = ExprValueMap.find_as(S);
-  if (SI == ExprValueMap.end())
-    return nullptr;
-#ifndef NDEBUG
-  if (VerifySCEVMap) {
-    // Check there is no dangling Value in the set returned.
-    for (const auto &VE : SI->second)
-      assert(ValueExprMap.count(VE.first));
-  }
-#endif
-  return &SI->second;
-}
-
-/// Erase Value from ValueExprMap and ExprValueMap. ValueExprMap.erase(V)
-/// cannot be used separately. eraseValueFromMap should be used to remove
-/// V from ValueExprMap and ExprValueMap at the same time.
-void ScalarEvolution::eraseValueFromMap(Value *V) {
-  ValueExprMapType::iterator I = ValueExprMap.find_as(V);
-  if (I != ValueExprMap.end()) {
-    const SCEV *S = I->second;
-    // Remove {V, 0} from the set of ExprValueMap[S]
-    if (SetVector<ValueOffsetPair> *SV = getSCEVValues(S))
-      SV->remove({V, nullptr});
-
-    // Remove {V, Offset} from the set of ExprValueMap[Stripped]
-    const SCEV *Stripped;
-    ConstantInt *Offset;
-    std::tie(Stripped, Offset) = splitAddExpr(S);
-    if (Offset != nullptr) {
-      if (SetVector<ValueOffsetPair> *SV = getSCEVValues(Stripped))
-        SV->remove({V, Offset});
-    }
-    ValueExprMap.erase(V);
-  }
-}
-
-/// Check whether value has nuw/nsw/exact set but SCEV does not.
-/// TODO: In reality it is better to check the poison recursevely
-/// but this is better than nothing.
-static bool SCEVLostPoisonFlags(const SCEV *S, const Value *V) {
-  if (auto *I = dyn_cast<Instruction>(V)) {
-    if (isa<OverflowingBinaryOperator>(I)) {
-      if (auto *NS = dyn_cast<SCEVNAryExpr>(S)) {
-        if (I->hasNoSignedWrap() && !NS->hasNoSignedWrap())
-          return true;
-        if (I->hasNoUnsignedWrap() && !NS->hasNoUnsignedWrap())
-          return true;
-      }
-    } else if (isa<PossiblyExactOperator>(I) && I->isExact())
-      return true;
-  }
-  return false;
-}
-
-/// Return an existing SCEV if it exists, otherwise analyze the expression and
-/// create a new one.
-const SCEV *ScalarEvolution::getSCEV(Value *V) {
-  assert(isSCEVable(V->getType()) && "Value is not SCEVable!");
-
-  const SCEV *S = getExistingSCEV(V);
-  if (S == nullptr) {
-    S = createSCEV(V);
-    // During PHI resolution, it is possible to create two SCEVs for the same
-    // V, so it is needed to double check whether V->S is inserted into
-    // ValueExprMap before insert S->{V, 0} into ExprValueMap.
-    std::pair<ValueExprMapType::iterator, bool> Pair =
-        ValueExprMap.insert({SCEVCallbackVH(V, this), S});
-    if (Pair.second && !SCEVLostPoisonFlags(S, V)) {
-      ExprValueMap[S].insert({V, nullptr});
-
-      // If S == Stripped + Offset, add Stripped -> {V, Offset} into
-      // ExprValueMap.
-      const SCEV *Stripped = S;
-      ConstantInt *Offset = nullptr;
-      std::tie(Stripped, Offset) = splitAddExpr(S);
-      // If stripped is SCEVUnknown, don't bother to save
-      // Stripped -> {V, offset}. It doesn't simplify and sometimes even
-      // increase the complexity of the expansion code.
-      // If V is GetElementPtrInst, don't save Stripped -> {V, offset}
-      // because it may generate add/sub instead of GEP in SCEV expansion.
-      if (Offset != nullptr && !isa<SCEVUnknown>(Stripped) &&
-          !isa<GetElementPtrInst>(V))
-        ExprValueMap[Stripped].insert({V, Offset});
-    }
-  }
-  return S;
-}
-
-const SCEV *ScalarEvolution::getExistingSCEV(Value *V) {
-  assert(isSCEVable(V->getType()) && "Value is not SCEVable!");
-
-  ValueExprMapType::iterator I = ValueExprMap.find_as(V);
-  if (I != ValueExprMap.end()) {
-    const SCEV *S = I->second;
-    if (checkValidity(S))
-      return S;
-    eraseValueFromMap(V);
-    forgetMemoizedResults(S);
-  }
-  return nullptr;
-}
-
-/// Return a SCEV corresponding to -V = -1*V
-const SCEV *ScalarEvolution::getNegativeSCEV(const SCEV *V,
-                                             SCEV::NoWrapFlags Flags) {
-  if (const SCEVConstant *VC = dyn_cast<SCEVConstant>(V))
-    return getConstant(
-               cast<ConstantInt>(ConstantExpr::getNeg(VC->getValue())));
-
-  Type *Ty = V->getType();
-  Ty = getEffectiveSCEVType(Ty);
-  return getMulExpr(
-      V, getConstant(cast<ConstantInt>(Constant::getAllOnesValue(Ty))), Flags);
-}
-
-/// Return a SCEV corresponding to ~V = -1-V
-const SCEV *ScalarEvolution::getNotSCEV(const SCEV *V) {
-  if (const SCEVConstant *VC = dyn_cast<SCEVConstant>(V))
-    return getConstant(
-                cast<ConstantInt>(ConstantExpr::getNot(VC->getValue())));
-
-  Type *Ty = V->getType();
-  Ty = getEffectiveSCEVType(Ty);
-  const SCEV *AllOnes =
-                   getConstant(cast<ConstantInt>(Constant::getAllOnesValue(Ty)));
-  return getMinusSCEV(AllOnes, V);
-}
-
-const SCEV *ScalarEvolution::getMinusSCEV(const SCEV *LHS, const SCEV *RHS,
-                                          SCEV::NoWrapFlags Flags,
-                                          unsigned Depth) {
-  // Fast path: X - X --> 0.
-  if (LHS == RHS)
-    return getZero(LHS->getType());
-
-  // We represent LHS - RHS as LHS + (-1)*RHS. This transformation
-  // makes it so that we cannot make much use of NUW.
-  auto AddFlags = SCEV::FlagAnyWrap;
-  const bool RHSIsNotMinSigned =
-      !getSignedRangeMin(RHS).isMinSignedValue();
-  if (maskFlags(Flags, SCEV::FlagNSW) == SCEV::FlagNSW) {
-    // Let M be the minimum representable signed value. Then (-1)*RHS
-    // signed-wraps if and only if RHS is M. That can happen even for
-    // a NSW subtraction because e.g. (-1)*M signed-wraps even though
-    // -1 - M does not. So to transfer NSW from LHS - RHS to LHS +
-    // (-1)*RHS, we need to prove that RHS != M.
-    //
-    // If LHS is non-negative and we know that LHS - RHS does not
-    // signed-wrap, then RHS cannot be M. So we can rule out signed-wrap
-    // either by proving that RHS > M or that LHS >= 0.
-    if (RHSIsNotMinSigned || isKnownNonNegative(LHS)) {
-      AddFlags = SCEV::FlagNSW;
-    }
-  }
-
-  // FIXME: Find a correct way to transfer NSW to (-1)*M when LHS -
-  // RHS is NSW and LHS >= 0.
-  //
-  // The difficulty here is that the NSW flag may have been proven
-  // relative to a loop that is to be found in a recurrence in LHS and
-  // not in RHS. Applying NSW to (-1)*M may then let the NSW have a
-  // larger scope than intended.
-  auto NegFlags = RHSIsNotMinSigned ? SCEV::FlagNSW : SCEV::FlagAnyWrap;
-
-  return getAddExpr(LHS, getNegativeSCEV(RHS, NegFlags), AddFlags, Depth);
-}
-
-const SCEV *
-ScalarEvolution::getTruncateOrZeroExtend(const SCEV *V, Type *Ty) {
-  Type *SrcTy = V->getType();
-  assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
-         "Cannot truncate or zero extend with non-integer arguments!");
-  if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
-    return V;  // No conversion
-  if (getTypeSizeInBits(SrcTy) > getTypeSizeInBits(Ty))
-    return getTruncateExpr(V, Ty);
-  return getZeroExtendExpr(V, Ty);
-}
-
-const SCEV *
-ScalarEvolution::getTruncateOrSignExtend(const SCEV *V,
-                                         Type *Ty) {
-  Type *SrcTy = V->getType();
-  assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
-         "Cannot truncate or zero extend with non-integer arguments!");
-  if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
-    return V;  // No conversion
-  if (getTypeSizeInBits(SrcTy) > getTypeSizeInBits(Ty))
-    return getTruncateExpr(V, Ty);
-  return getSignExtendExpr(V, Ty);
-}
-
-const SCEV *
-ScalarEvolution::getNoopOrZeroExtend(const SCEV *V, Type *Ty) {
-  Type *SrcTy = V->getType();
-  assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
-         "Cannot noop or zero extend with non-integer arguments!");
-  assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
-         "getNoopOrZeroExtend cannot truncate!");
-  if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
-    return V;  // No conversion
-  return getZeroExtendExpr(V, Ty);
-}
-
-const SCEV *
-ScalarEvolution::getNoopOrSignExtend(const SCEV *V, Type *Ty) {
-  Type *SrcTy = V->getType();
-  assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
-         "Cannot noop or sign extend with non-integer arguments!");
-  assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
-         "getNoopOrSignExtend cannot truncate!");
-  if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
-    return V;  // No conversion
-  return getSignExtendExpr(V, Ty);
-}
-
-const SCEV *
-ScalarEvolution::getNoopOrAnyExtend(const SCEV *V, Type *Ty) {
-  Type *SrcTy = V->getType();
-  assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
-         "Cannot noop or any extend with non-integer arguments!");
-  assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
-         "getNoopOrAnyExtend cannot truncate!");
-  if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
-    return V;  // No conversion
-  return getAnyExtendExpr(V, Ty);
-}
-
-const SCEV *
-ScalarEvolution::getTruncateOrNoop(const SCEV *V, Type *Ty) {
-  Type *SrcTy = V->getType();
-  assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
-         "Cannot truncate or noop with non-integer arguments!");
-  assert(getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) &&
-         "getTruncateOrNoop cannot extend!");
-  if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
-    return V;  // No conversion
-  return getTruncateExpr(V, Ty);
-}
-
-const SCEV *ScalarEvolution::getUMaxFromMismatchedTypes(const SCEV *LHS,
-                                                        const SCEV *RHS) {
-  const SCEV *PromotedLHS = LHS;
-  const SCEV *PromotedRHS = RHS;
-
-  if (getTypeSizeInBits(LHS->getType()) > getTypeSizeInBits(RHS->getType()))
-    PromotedRHS = getZeroExtendExpr(RHS, LHS->getType());
-  else
-    PromotedLHS = getNoopOrZeroExtend(LHS, RHS->getType());
-
-  return getUMaxExpr(PromotedLHS, PromotedRHS);
-}
-
-const SCEV *ScalarEvolution::getUMinFromMismatchedTypes(const SCEV *LHS,
-                                                        const SCEV *RHS) {
-  SmallVector<const SCEV *, 2> Ops = { LHS, RHS };
-  return getUMinFromMismatchedTypes(Ops);
-}
-
-const SCEV *ScalarEvolution::getUMinFromMismatchedTypes(
-    SmallVectorImpl<const SCEV *> &Ops) {
-  assert(!Ops.empty() && "At least one operand must be!");
-  // Trivial case.
-  if (Ops.size() == 1)
-    return Ops[0];
-
-  // Find the max type first.
-  Type *MaxType = nullptr;
-  for (auto *S : Ops)
-    if (MaxType)
-      MaxType = getWiderType(MaxType, S->getType());
-    else
-      MaxType = S->getType();
-
-  // Extend all ops to max type.
-  SmallVector<const SCEV *, 2> PromotedOps;
-  for (auto *S : Ops)
-    PromotedOps.push_back(getNoopOrZeroExtend(S, MaxType));
-
-  // Generate umin.
-  return getUMinExpr(PromotedOps);
-}
-
-const SCEV *ScalarEvolution::getPointerBase(const SCEV *V) {
-  // A pointer operand may evaluate to a nonpointer expression, such as null.
-  if (!V->getType()->isPointerTy())
-    return V;
-
-  if (const SCEVCastExpr *Cast = dyn_cast<SCEVCastExpr>(V)) {
-    return getPointerBase(Cast->getOperand());
-  } else if (const SCEVNAryExpr *NAry = dyn_cast<SCEVNAryExpr>(V)) {
-    const SCEV *PtrOp = nullptr;
-    for (const SCEV *NAryOp : NAry->operands()) {
-      if (NAryOp->getType()->isPointerTy()) {
-        // Cannot find the base of an expression with multiple pointer operands.
-        if (PtrOp)
-          return V;
-        PtrOp = NAryOp;
-      }
-    }
-    if (!PtrOp)
-      return V;
-    return getPointerBase(PtrOp);
-  }
-  return V;
-}
-
-/// Push users of the given Instruction onto the given Worklist.
-static void
-PushDefUseChildren(Instruction *I,
-                   SmallVectorImpl<Instruction *> &Worklist) {
-  // Push the def-use children onto the Worklist stack.
-  for (User *U : I->users())
-    Worklist.push_back(cast<Instruction>(U));
-}
-
-void ScalarEvolution::forgetSymbolicName(Instruction *PN, const SCEV *SymName) {
-  SmallVector<Instruction *, 16> Worklist;
-  PushDefUseChildren(PN, Worklist);
-
-  SmallPtrSet<Instruction *, 8> Visited;
-  Visited.insert(PN);
-  while (!Worklist.empty()) {
-    Instruction *I = Worklist.pop_back_val();
-    if (!Visited.insert(I).second)
-      continue;
-
-    auto It = ValueExprMap.find_as(static_cast<Value *>(I));
-    if (It != ValueExprMap.end()) {
-      const SCEV *Old = It->second;
-
-      // Short-circuit the def-use traversal if the symbolic name
-      // ceases to appear in expressions.
-      if (Old != SymName && !hasOperand(Old, SymName))
-        continue;
-
-      // SCEVUnknown for a PHI either means that it has an unrecognized
-      // structure, it's a PHI that's in the progress of being computed
-      // by createNodeForPHI, or it's a single-value PHI. In the first case,
-      // additional loop trip count information isn't going to change anything.
-      // In the second case, createNodeForPHI will perform the necessary
-      // updates on its own when it gets to that point. In the third, we do
-      // want to forget the SCEVUnknown.
-      if (!isa<PHINode>(I) ||
-          !isa<SCEVUnknown>(Old) ||
-          (I != PN && Old == SymName)) {
-        eraseValueFromMap(It->first);
-        forgetMemoizedResults(Old);
-      }
-    }
-
-    PushDefUseChildren(I, Worklist);
-  }
-}
-
-namespace {
-
-/// Takes SCEV S and Loop L. For each AddRec sub-expression, use its start
-/// expression in case its Loop is L. If it is not L then
-/// if IgnoreOtherLoops is true then use AddRec itself
-/// otherwise rewrite cannot be done.
-/// If SCEV contains non-invariant unknown SCEV rewrite cannot be done.
-class SCEVInitRewriter : public SCEVRewriteVisitor<SCEVInitRewriter> {
-public:
-  static const SCEV *rewrite(const SCEV *S, const Loop *L, ScalarEvolution &SE,
-                             bool IgnoreOtherLoops = true) {
-    SCEVInitRewriter Rewriter(L, SE);
-    const SCEV *Result = Rewriter.visit(S);
-    if (Rewriter.hasSeenLoopVariantSCEVUnknown())
-      return SE.getCouldNotCompute();
-    return Rewriter.hasSeenOtherLoops() && !IgnoreOtherLoops
-               ? SE.getCouldNotCompute()
-               : Result;
-  }
-
-  const SCEV *visitUnknown(const SCEVUnknown *Expr) {
-    if (!SE.isLoopInvariant(Expr, L))
-      SeenLoopVariantSCEVUnknown = true;
-    return Expr;
-  }
-
-  const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) {
-    // Only re-write AddRecExprs for this loop.
-    if (Expr->getLoop() == L)
-      return Expr->getStart();
-    SeenOtherLoops = true;
-    return Expr;
-  }
-
-  bool hasSeenLoopVariantSCEVUnknown() { return SeenLoopVariantSCEVUnknown; }
-
-  bool hasSeenOtherLoops() { return SeenOtherLoops; }
-
-private:
-  explicit SCEVInitRewriter(const Loop *L, ScalarEvolution &SE)
-      : SCEVRewriteVisitor(SE), L(L) {}
-
-  const Loop *L;
-  bool SeenLoopVariantSCEVUnknown = false;
-  bool SeenOtherLoops = false;
-};
-
-/// Takes SCEV S and Loop L. For each AddRec sub-expression, use its post
-/// increment expression in case its Loop is L. If it is not L then
-/// use AddRec itself.
-/// If SCEV contains non-invariant unknown SCEV rewrite cannot be done.
-class SCEVPostIncRewriter : public SCEVRewriteVisitor<SCEVPostIncRewriter> {
-public:
-  static const SCEV *rewrite(const SCEV *S, const Loop *L, ScalarEvolution &SE) {
-    SCEVPostIncRewriter Rewriter(L, SE);
-    const SCEV *Result = Rewriter.visit(S);
-    return Rewriter.hasSeenLoopVariantSCEVUnknown()
-        ? SE.getCouldNotCompute()
-        : Result;
-  }
-
-  const SCEV *visitUnknown(const SCEVUnknown *Expr) {
-    if (!SE.isLoopInvariant(Expr, L))
-      SeenLoopVariantSCEVUnknown = true;
-    return Expr;
-  }
-
-  const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) {
-    // Only re-write AddRecExprs for this loop.
-    if (Expr->getLoop() == L)
-      return Expr->getPostIncExpr(SE);
-    SeenOtherLoops = true;
-    return Expr;
-  }
-
-  bool hasSeenLoopVariantSCEVUnknown() { return SeenLoopVariantSCEVUnknown; }
-
-  bool hasSeenOtherLoops() { return SeenOtherLoops; }
-
-private:
-  explicit SCEVPostIncRewriter(const Loop *L, ScalarEvolution &SE)
-      : SCEVRewriteVisitor(SE), L(L) {}
-
-  const Loop *L;
-  bool SeenLoopVariantSCEVUnknown = false;
-  bool SeenOtherLoops = false;
-};
-
-/// This class evaluates the compare condition by matching it against the
-/// condition of loop latch. If there is a match we assume a true value
-/// for the condition while building SCEV nodes.
-class SCEVBackedgeConditionFolder
-    : public SCEVRewriteVisitor<SCEVBackedgeConditionFolder> {
-public:
-  static const SCEV *rewrite(const SCEV *S, const Loop *L,
-                             ScalarEvolution &SE) {
-    bool IsPosBECond = false;
-    Value *BECond = nullptr;
-    if (BasicBlock *Latch = L->getLoopLatch()) {
-      BranchInst *BI = dyn_cast<BranchInst>(Latch->getTerminator());
-      if (BI && BI->isConditional()) {
-        assert(BI->getSuccessor(0) != BI->getSuccessor(1) &&
-               "Both outgoing branches should not target same header!");
-        BECond = BI->getCondition();
-        IsPosBECond = BI->getSuccessor(0) == L->getHeader();
-      } else {
-        return S;
-      }
-    }
-    SCEVBackedgeConditionFolder Rewriter(L, BECond, IsPosBECond, SE);
-    return Rewriter.visit(S);
-  }
-
-  const SCEV *visitUnknown(const SCEVUnknown *Expr) {
-    const SCEV *Result = Expr;
-    bool InvariantF = SE.isLoopInvariant(Expr, L);
-
-    if (!InvariantF) {
-      Instruction *I = cast<Instruction>(Expr->getValue());
-      switch (I->getOpcode()) {
-      case Instruction::Select: {
-        SelectInst *SI = cast<SelectInst>(I);
-        Optional<const SCEV *> Res =
-            compareWithBackedgeCondition(SI->getCondition());
-        if (Res.hasValue()) {
-          bool IsOne = cast<SCEVConstant>(Res.getValue())->getValue()->isOne();
-          Result = SE.getSCEV(IsOne ? SI->getTrueValue() : SI->getFalseValue());
-        }
-        break;
-      }
-      default: {
-        Optional<const SCEV *> Res = compareWithBackedgeCondition(I);
-        if (Res.hasValue())
-          Result = Res.getValue();
-        break;
-      }
-      }
-    }
-    return Result;
-  }
-
-private:
-  explicit SCEVBackedgeConditionFolder(const Loop *L, Value *BECond,
-                                       bool IsPosBECond, ScalarEvolution &SE)
-      : SCEVRewriteVisitor(SE), L(L), BackedgeCond(BECond),
-        IsPositiveBECond(IsPosBECond) {}
-
-  Optional<const SCEV *> compareWithBackedgeCondition(Value *IC);
-
-  const Loop *L;
-  /// Loop back condition.
-  Value *BackedgeCond = nullptr;
-  /// Set to true if loop back is on positive branch condition.
-  bool IsPositiveBECond;
-};
-
-Optional<const SCEV *>
-SCEVBackedgeConditionFolder::compareWithBackedgeCondition(Value *IC) {
-
-  // If value matches the backedge condition for loop latch,
-  // then return a constant evolution node based on loopback
-  // branch taken.
-  if (BackedgeCond == IC)
-    return IsPositiveBECond ? SE.getOne(Type::getInt1Ty(SE.getContext()))
-                            : SE.getZero(Type::getInt1Ty(SE.getContext()));
-  return None;
-}
-
-class SCEVShiftRewriter : public SCEVRewriteVisitor<SCEVShiftRewriter> {
-public:
-  static const SCEV *rewrite(const SCEV *S, const Loop *L,
-                             ScalarEvolution &SE) {
-    SCEVShiftRewriter Rewriter(L, SE);
-    const SCEV *Result = Rewriter.visit(S);
-    return Rewriter.isValid() ? Result : SE.getCouldNotCompute();
-  }
-
-  const SCEV *visitUnknown(const SCEVUnknown *Expr) {
-    // Only allow AddRecExprs for this loop.
-    if (!SE.isLoopInvariant(Expr, L))
-      Valid = false;
-    return Expr;
-  }
-
-  const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) {
-    if (Expr->getLoop() == L && Expr->isAffine())
-      return SE.getMinusSCEV(Expr, Expr->getStepRecurrence(SE));
-    Valid = false;
-    return Expr;
-  }
-
-  bool isValid() { return Valid; }
-
-private:
-  explicit SCEVShiftRewriter(const Loop *L, ScalarEvolution &SE)
-      : SCEVRewriteVisitor(SE), L(L) {}
-
-  const Loop *L;
-  bool Valid = true;
-};
-
-} // end anonymous namespace
-
-SCEV::NoWrapFlags
-ScalarEvolution::proveNoWrapViaConstantRanges(const SCEVAddRecExpr *AR) {
-  if (!AR->isAffine())
-    return SCEV::FlagAnyWrap;
-
-  using OBO = OverflowingBinaryOperator;
-
-  SCEV::NoWrapFlags Result = SCEV::FlagAnyWrap;
-
-  if (!AR->hasNoSignedWrap()) {
-    ConstantRange AddRecRange = getSignedRange(AR);
-    ConstantRange IncRange = getSignedRange(AR->getStepRecurrence(*this));
-
-    auto NSWRegion = ConstantRange::makeGuaranteedNoWrapRegion(
-        Instruction::Add, IncRange, OBO::NoSignedWrap);
-    if (NSWRegion.contains(AddRecRange))
-      Result = ScalarEvolution::setFlags(Result, SCEV::FlagNSW);
-  }
-
-  if (!AR->hasNoUnsignedWrap()) {
-    ConstantRange AddRecRange = getUnsignedRange(AR);
-    ConstantRange IncRange = getUnsignedRange(AR->getStepRecurrence(*this));
-
-    auto NUWRegion = ConstantRange::makeGuaranteedNoWrapRegion(
-        Instruction::Add, IncRange, OBO::NoUnsignedWrap);
-    if (NUWRegion.contains(AddRecRange))
-      Result = ScalarEvolution::setFlags(Result, SCEV::FlagNUW);
-  }
-
-  return Result;
-}
-
-namespace {
-
-/// Represents an abstract binary operation.  This may exist as a
-/// normal instruction or constant expression, or may have been
-/// derived from an expression tree.
-struct BinaryOp {
-  unsigned Opcode;
-  Value *LHS;
-  Value *RHS;
-  bool IsNSW = false;
-  bool IsNUW = false;
-
-  /// Op is set if this BinaryOp corresponds to a concrete LLVM instruction or
-  /// constant expression.
-  Operator *Op = nullptr;
-
-  explicit BinaryOp(Operator *Op)
-      : Opcode(Op->getOpcode()), LHS(Op->getOperand(0)), RHS(Op->getOperand(1)),
-        Op(Op) {
-    if (auto *OBO = dyn_cast<OverflowingBinaryOperator>(Op)) {
-      IsNSW = OBO->hasNoSignedWrap();
-      IsNUW = OBO->hasNoUnsignedWrap();
-    }
-  }
-
-  explicit BinaryOp(unsigned Opcode, Value *LHS, Value *RHS, bool IsNSW = false,
-                    bool IsNUW = false)
-      : Opcode(Opcode), LHS(LHS), RHS(RHS), IsNSW(IsNSW), IsNUW(IsNUW) {}
-};
-
-} // end anonymous namespace
-
-/// Try to map \p V into a BinaryOp, and return \c None on failure.
-static Optional<BinaryOp> MatchBinaryOp(Value *V, DominatorTree &DT) {
-  auto *Op = dyn_cast<Operator>(V);
-  if (!Op)
-    return None;
-
-  // Implementation detail: all the cleverness here should happen without
-  // creating new SCEV expressions -- our caller knowns tricks to avoid creating
-  // SCEV expressions when possible, and we should not break that.
-
-  switch (Op->getOpcode()) {
-  case Instruction::Add:
-  case Instruction::Sub:
-  case Instruction::Mul:
-  case Instruction::UDiv:
-  case Instruction::URem:
-  case Instruction::And:
-  case Instruction::Or:
-  case Instruction::AShr:
-  case Instruction::Shl:
-    return BinaryOp(Op);
-
-  case Instruction::Xor:
-    if (auto *RHSC = dyn_cast<ConstantInt>(Op->getOperand(1)))
-      // If the RHS of the xor is a signmask, then this is just an add.
-      // Instcombine turns add of signmask into xor as a strength reduction step.
-      if (RHSC->getValue().isSignMask())
-        return BinaryOp(Instruction::Add, Op->getOperand(0), Op->getOperand(1));
-    return BinaryOp(Op);
-
-  case Instruction::LShr:
-    // Turn logical shift right of a constant into a unsigned divide.
-    if (ConstantInt *SA = dyn_cast<ConstantInt>(Op->getOperand(1))) {
-      uint32_t BitWidth = cast<IntegerType>(Op->getType())->getBitWidth();
-
-      // If the shift count is not less than the bitwidth, the result of
-      // the shift is undefined. Don't try to analyze it, because the
-      // resolution chosen here may differ from the resolution chosen in
-      // other parts of the compiler.
-      if (SA->getValue().ult(BitWidth)) {
-        Constant *X =
-            ConstantInt::get(SA->getContext(),
-                             APInt::getOneBitSet(BitWidth, SA->getZExtValue()));
-        return BinaryOp(Instruction::UDiv, Op->getOperand(0), X);
-      }
-    }
-    return BinaryOp(Op);
-
-  case Instruction::ExtractValue: {
-    auto *EVI = cast<ExtractValueInst>(Op);
-    if (EVI->getNumIndices() != 1 || EVI->getIndices()[0] != 0)
-      break;
-
-    auto *CI = dyn_cast<CallInst>(EVI->getAggregateOperand());
-    if (!CI)
-      break;
-
-    if (auto *F = CI->getCalledFunction())
-      switch (F->getIntrinsicID()) {
-      case Intrinsic::sadd_with_overflow:
-      case Intrinsic::uadd_with_overflow:
-        if (!isOverflowIntrinsicNoWrap(cast<IntrinsicInst>(CI), DT))
-          return BinaryOp(Instruction::Add, CI->getArgOperand(0),
-                          CI->getArgOperand(1));
-
-        // Now that we know that all uses of the arithmetic-result component of
-        // CI are guarded by the overflow check, we can go ahead and pretend
-        // that the arithmetic is non-overflowing.
-        if (F->getIntrinsicID() == Intrinsic::sadd_with_overflow)
-          return BinaryOp(Instruction::Add, CI->getArgOperand(0),
-                          CI->getArgOperand(1), /* IsNSW = */ true,
-                          /* IsNUW = */ false);
-        else
-          return BinaryOp(Instruction::Add, CI->getArgOperand(0),
-                          CI->getArgOperand(1), /* IsNSW = */ false,
-                          /* IsNUW*/ true);
-      case Intrinsic::ssub_with_overflow:
-      case Intrinsic::usub_with_overflow:
-        if (!isOverflowIntrinsicNoWrap(cast<IntrinsicInst>(CI), DT))
-          return BinaryOp(Instruction::Sub, CI->getArgOperand(0),
-                          CI->getArgOperand(1));
-
-        // The same reasoning as sadd/uadd above.
-        if (F->getIntrinsicID() == Intrinsic::ssub_with_overflow)
-          return BinaryOp(Instruction::Sub, CI->getArgOperand(0),
-                          CI->getArgOperand(1), /* IsNSW = */ true,
-                          /* IsNUW = */ false);
-        else
-          return BinaryOp(Instruction::Sub, CI->getArgOperand(0),
-                          CI->getArgOperand(1), /* IsNSW = */ false,
-                          /* IsNUW = */ true);
-      case Intrinsic::smul_with_overflow:
-      case Intrinsic::umul_with_overflow:
-        return BinaryOp(Instruction::Mul, CI->getArgOperand(0),
-                        CI->getArgOperand(1));
-      default:
-        break;
-      }
-    break;
-  }
-
-  default:
-    break;
-  }
-
-  return None;
-}
-
-/// Helper function to createAddRecFromPHIWithCasts. We have a phi
-/// node whose symbolic (unknown) SCEV is \p SymbolicPHI, which is updated via
-/// the loop backedge by a SCEVAddExpr, possibly also with a few casts on the
-/// way. This function checks if \p Op, an operand of this SCEVAddExpr,
-/// follows one of the following patterns:
-/// Op == (SExt ix (Trunc iy (%SymbolicPHI) to ix) to iy)
-/// Op == (ZExt ix (Trunc iy (%SymbolicPHI) to ix) to iy)
-/// If the SCEV expression of \p Op conforms with one of the expected patterns
-/// we return the type of the truncation operation, and indicate whether the
-/// truncated type should be treated as signed/unsigned by setting
-/// \p Signed to true/false, respectively.
-static Type *isSimpleCastedPHI(const SCEV *Op, const SCEVUnknown *SymbolicPHI,
-                               bool &Signed, ScalarEvolution &SE) {
-  // The case where Op == SymbolicPHI (that is, with no type conversions on
-  // the way) is handled by the regular add recurrence creating logic and
-  // would have already been triggered in createAddRecForPHI. Reaching it here
-  // means that createAddRecFromPHI had failed for this PHI before (e.g.,
-  // because one of the other operands of the SCEVAddExpr updating this PHI is
-  // not invariant).
-  //
-  // Here we look for the case where Op = (ext(trunc(SymbolicPHI))), and in
-  // this case predicates that allow us to prove that Op == SymbolicPHI will
-  // be added.
-  if (Op == SymbolicPHI)
-    return nullptr;
-
-  unsigned SourceBits = SE.getTypeSizeInBits(SymbolicPHI->getType());
-  unsigned NewBits = SE.getTypeSizeInBits(Op->getType());
-  if (SourceBits != NewBits)
-    return nullptr;
-
-  const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(Op);
-  const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(Op);
-  if (!SExt && !ZExt)
-    return nullptr;
-  const SCEVTruncateExpr *Trunc =
-      SExt ? dyn_cast<SCEVTruncateExpr>(SExt->getOperand())
-           : dyn_cast<SCEVTruncateExpr>(ZExt->getOperand());
-  if (!Trunc)
-    return nullptr;
-  const SCEV *X = Trunc->getOperand();
-  if (X != SymbolicPHI)
-    return nullptr;
-  Signed = SExt != nullptr;
-  return Trunc->getType();
-}
-
-static const Loop *isIntegerLoopHeaderPHI(const PHINode *PN, LoopInfo &LI) {
-  if (!PN->getType()->isIntegerTy())
-    return nullptr;
-  const Loop *L = LI.getLoopFor(PN->getParent());
-  if (!L || L->getHeader() != PN->getParent())
-    return nullptr;
-  return L;
-}
-
-// Analyze \p SymbolicPHI, a SCEV expression of a phi node, and check if the
-// computation that updates the phi follows the following pattern:
-//   (SExt/ZExt ix (Trunc iy (%SymbolicPHI) to ix) to iy) + InvariantAccum
-// which correspond to a phi->trunc->sext/zext->add->phi update chain.
-// If so, try to see if it can be rewritten as an AddRecExpr under some
-// Predicates. If successful, return them as a pair. Also cache the results
-// of the analysis.
-//
-// Example usage scenario:
-//    Say the Rewriter is called for the following SCEV:
-//         8 * ((sext i32 (trunc i64 %X to i32) to i64) + %Step)
-//    where:
-//         %X = phi i64 (%Start, %BEValue)
-//    It will visitMul->visitAdd->visitSExt->visitTrunc->visitUnknown(%X),
-//    and call this function with %SymbolicPHI = %X.
-//
-//    The analysis will find that the value coming around the backedge has
-//    the following SCEV:
-//         BEValue = ((sext i32 (trunc i64 %X to i32) to i64) + %Step)
-//    Upon concluding that this matches the desired pattern, the function
-//    will return the pair {NewAddRec, SmallPredsVec} where:
-//         NewAddRec = {%Start,+,%Step}
-//         SmallPredsVec = {P1, P2, P3} as follows:
-//           P1(WrapPred): AR: {trunc(%Start),+,(trunc %Step)}<nsw> Flags: <nssw>
-//           P2(EqualPred): %Start == (sext i32 (trunc i64 %Start to i32) to i64)
-//           P3(EqualPred): %Step == (sext i32 (trunc i64 %Step to i32) to i64)
-//    The returned pair means that SymbolicPHI can be rewritten into NewAddRec
-//    under the predicates {P1,P2,P3}.
-//    This predicated rewrite will be cached in PredicatedSCEVRewrites:
-//         PredicatedSCEVRewrites[{%X,L}] = {NewAddRec, {P1,P2,P3)}
-//
-// TODO's:
-//
-// 1) Extend the Induction descriptor to also support inductions that involve
-//    casts: When needed (namely, when we are called in the context of the
-//    vectorizer induction analysis), a Set of cast instructions will be
-//    populated by this method, and provided back to isInductionPHI. This is
-//    needed to allow the vectorizer to properly record them to be ignored by
-//    the cost model and to avoid vectorizing them (otherwise these casts,
-//    which are redundant under the runtime overflow checks, will be
-//    vectorized, which can be costly).
-//
-// 2) Support additional induction/PHISCEV patterns: We also want to support
-//    inductions where the sext-trunc / zext-trunc operations (partly) occur
-//    after the induction update operation (the induction increment):
-//
-//      (Trunc iy (SExt/ZExt ix (%SymbolicPHI + InvariantAccum) to iy) to ix)
-//    which correspond to a phi->add->trunc->sext/zext->phi update chain.
-//
-//      (Trunc iy ((SExt/ZExt ix (%SymbolicPhi) to iy) + InvariantAccum) to ix)
-//    which correspond to a phi->trunc->add->sext/zext->phi update chain.
-//
-// 3) Outline common code with createAddRecFromPHI to avoid duplication.
-Optional<std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>>>
-ScalarEvolution::createAddRecFromPHIWithCastsImpl(const SCEVUnknown *SymbolicPHI) {
-  SmallVector<const SCEVPredicate *, 3> Predicates;
-
-  // *** Part1: Analyze if we have a phi-with-cast pattern for which we can
-  // return an AddRec expression under some predicate.
-
-  auto *PN = cast<PHINode>(SymbolicPHI->getValue());
-  const Loop *L = isIntegerLoopHeaderPHI(PN, LI);
-  assert(L && "Expecting an integer loop header phi");
-
-  // The loop may have multiple entrances or multiple exits; we can analyze
-  // this phi as an addrec if it has a unique entry value and a unique
-  // backedge value.
-  Value *BEValueV = nullptr, *StartValueV = nullptr;
-  for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
-    Value *V = PN->getIncomingValue(i);
-    if (L->contains(PN->getIncomingBlock(i))) {
-      if (!BEValueV) {
-        BEValueV = V;
-      } else if (BEValueV != V) {
-        BEValueV = nullptr;
-        break;
-      }
-    } else if (!StartValueV) {
-      StartValueV = V;
-    } else if (StartValueV != V) {
-      StartValueV = nullptr;
-      break;
-    }
-  }
-  if (!BEValueV || !StartValueV)
-    return None;
-
-  const SCEV *BEValue = getSCEV(BEValueV);
-
-  // If the value coming around the backedge is an add with the symbolic
-  // value we just inserted, possibly with casts that we can ignore under
-  // an appropriate runtime guard, then we found a simple induction variable!
-  const auto *Add = dyn_cast<SCEVAddExpr>(BEValue);
-  if (!Add)
-    return None;
-
-  // If there is a single occurrence of the symbolic value, possibly
-  // casted, replace it with a recurrence.
-  unsigned FoundIndex = Add->getNumOperands();
-  Type *TruncTy = nullptr;
-  bool Signed;
-  for (unsigned i = 0, e = Add->getNumOperands(); i != e; ++i)
-    if ((TruncTy =
-             isSimpleCastedPHI(Add->getOperand(i), SymbolicPHI, Signed, *this)))
-      if (FoundIndex == e) {
-        FoundIndex = i;
-        break;
-      }
-
-  if (FoundIndex == Add->getNumOperands())
-    return None;
-
-  // Create an add with everything but the specified operand.
-  SmallVector<const SCEV *, 8> Ops;
-  for (unsigned i = 0, e = Add->getNumOperands(); i != e; ++i)
-    if (i != FoundIndex)
-      Ops.push_back(Add->getOperand(i));
-  const SCEV *Accum = getAddExpr(Ops);
-
-  // The runtime checks will not be valid if the step amount is
-  // varying inside the loop.
-  if (!isLoopInvariant(Accum, L))
-    return None;
-
-  // *** Part2: Create the predicates
-
-  // Analysis was successful: we have a phi-with-cast pattern for which we
-  // can return an AddRec expression under the following predicates:
-  //
-  // P1: A Wrap predicate that guarantees that Trunc(Start) + i*Trunc(Accum)
-  //     fits within the truncated type (does not overflow) for i = 0 to n-1.
-  // P2: An Equal predicate that guarantees that
-  //     Start = (Ext ix (Trunc iy (Start) to ix) to iy)
-  // P3: An Equal predicate that guarantees that
-  //     Accum = (Ext ix (Trunc iy (Accum) to ix) to iy)
-  //
-  // As we next prove, the above predicates guarantee that:
-  //     Start + i*Accum = (Ext ix (Trunc iy ( Start + i*Accum ) to ix) to iy)
-  //
-  //
-  // More formally, we want to prove that:
-  //     Expr(i+1) = Start + (i+1) * Accum
-  //               = (Ext ix (Trunc iy (Expr(i)) to ix) to iy) + Accum
-  //
-  // Given that:
-  // 1) Expr(0) = Start
-  // 2) Expr(1) = Start + Accum
-  //            = (Ext ix (Trunc iy (Start) to ix) to iy) + Accum :: from P2
-  // 3) Induction hypothesis (step i):
-  //    Expr(i) = (Ext ix (Trunc iy (Expr(i-1)) to ix) to iy) + Accum
-  //
-  // Proof:
-  //  Expr(i+1) =
-  //   = Start + (i+1)*Accum
-  //   = (Start + i*Accum) + Accum
-  //   = Expr(i) + Accum
-  //   = (Ext ix (Trunc iy (Expr(i-1)) to ix) to iy) + Accum + Accum
-  //                                                             :: from step i
-  //
-  //   = (Ext ix (Trunc iy (Start + (i-1)*Accum) to ix) to iy) + Accum + Accum
-  //
-  //   = (Ext ix (Trunc iy (Start + (i-1)*Accum) to ix) to iy)
-  //     + (Ext ix (Trunc iy (Accum) to ix) to iy)
-  //     + Accum                                                     :: from P3
-  //
-  //   = (Ext ix (Trunc iy ((Start + (i-1)*Accum) + Accum) to ix) to iy)
-  //     + Accum                            :: from P1: Ext(x)+Ext(y)=>Ext(x+y)
-  //
-  //   = (Ext ix (Trunc iy (Start + i*Accum) to ix) to iy) + Accum
-  //   = (Ext ix (Trunc iy (Expr(i)) to ix) to iy) + Accum
-  //
-  // By induction, the same applies to all iterations 1<=i<n:
-  //
-
-  // Create a truncated addrec for which we will add a no overflow check (P1).
-  const SCEV *StartVal = getSCEV(StartValueV);
-  const SCEV *PHISCEV =
-      getAddRecExpr(getTruncateExpr(StartVal, TruncTy),
-                    getTruncateExpr(Accum, TruncTy), L, SCEV::FlagAnyWrap);
-
-  // PHISCEV can be either a SCEVConstant or a SCEVAddRecExpr.
-  // ex: If truncated Accum is 0 and StartVal is a constant, then PHISCEV
-  // will be constant.
-  //
-  //  If PHISCEV is a constant, then P1 degenerates into P2 or P3, so we don't
-  // add P1.
-  if (const auto *AR = dyn_cast<SCEVAddRecExpr>(PHISCEV)) {
-    SCEVWrapPredicate::IncrementWrapFlags AddedFlags =
-        Signed ? SCEVWrapPredicate::IncrementNSSW
-               : SCEVWrapPredicate::IncrementNUSW;
-    const SCEVPredicate *AddRecPred = getWrapPredicate(AR, AddedFlags);
-    Predicates.push_back(AddRecPred);
-  }
-
-  // Create the Equal Predicates P2,P3:
-
-  // It is possible that the predicates P2 and/or P3 are computable at
-  // compile time due to StartVal and/or Accum being constants.
-  // If either one is, then we can check that now and escape if either P2
-  // or P3 is false.
-
-  // Construct the extended SCEV: (Ext ix (Trunc iy (Expr) to ix) to iy)
-  // for each of StartVal and Accum
-  auto getExtendedExpr = [&](const SCEV *Expr,
-                             bool CreateSignExtend) -> const SCEV * {
-    assert(isLoopInvariant(Expr, L) && "Expr is expected to be invariant");
-    const SCEV *TruncatedExpr = getTruncateExpr(Expr, TruncTy);
-    const SCEV *ExtendedExpr =
-        CreateSignExtend ? getSignExtendExpr(TruncatedExpr, Expr->getType())
-                         : getZeroExtendExpr(TruncatedExpr, Expr->getType());
-    return ExtendedExpr;
-  };
-
-  // Given:
-  //  ExtendedExpr = (Ext ix (Trunc iy (Expr) to ix) to iy
-  //               = getExtendedExpr(Expr)
-  // Determine whether the predicate P: Expr == ExtendedExpr
-  // is known to be false at compile time
-  auto PredIsKnownFalse = [&](const SCEV *Expr,
-                              const SCEV *ExtendedExpr) -> bool {
-    return Expr != ExtendedExpr &&
-           isKnownPredicate(ICmpInst::ICMP_NE, Expr, ExtendedExpr);
-  };
-
-  const SCEV *StartExtended = getExtendedExpr(StartVal, Signed);
-  if (PredIsKnownFalse(StartVal, StartExtended)) {
-    LLVM_DEBUG(dbgs() << "P2 is compile-time false\n";);
-    return None;
-  }
-
-  // The Step is always Signed (because the overflow checks are either
-  // NSSW or NUSW)
-  const SCEV *AccumExtended = getExtendedExpr(Accum, /*CreateSignExtend=*/true);
-  if (PredIsKnownFalse(Accum, AccumExtended)) {
-    LLVM_DEBUG(dbgs() << "P3 is compile-time false\n";);
-    return None;
-  }
-
-  auto AppendPredicate = [&](const SCEV *Expr,
-                             const SCEV *ExtendedExpr) -> void {
-    if (Expr != ExtendedExpr &&
-        !isKnownPredicate(ICmpInst::ICMP_EQ, Expr, ExtendedExpr)) {
-      const SCEVPredicate *Pred = getEqualPredicate(Expr, ExtendedExpr);
-      LLVM_DEBUG(dbgs() << "Added Predicate: " << *Pred);
-      Predicates.push_back(Pred);
-    }
-  };
-
-  AppendPredicate(StartVal, StartExtended);
-  AppendPredicate(Accum, AccumExtended);
-
-  // *** Part3: Predicates are ready. Now go ahead and create the new addrec in
-  // which the casts had been folded away. The caller can rewrite SymbolicPHI
-  // into NewAR if it will also add the runtime overflow checks specified in
-  // Predicates.
-  auto *NewAR = getAddRecExpr(StartVal, Accum, L, SCEV::FlagAnyWrap);
-
-  std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>> PredRewrite =
-      std::make_pair(NewAR, Predicates);
-  // Remember the result of the analysis for this SCEV at this locayyytion.
-  PredicatedSCEVRewrites[{SymbolicPHI, L}] = PredRewrite;
-  return PredRewrite;
-}
-
-Optional<std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>>>
-ScalarEvolution::createAddRecFromPHIWithCasts(const SCEVUnknown *SymbolicPHI) {
-  auto *PN = cast<PHINode>(SymbolicPHI->getValue());
-  const Loop *L = isIntegerLoopHeaderPHI(PN, LI);
-  if (!L)
-    return None;
-
-  // Check to see if we already analyzed this PHI.
-  auto I = PredicatedSCEVRewrites.find({SymbolicPHI, L});
-  if (I != PredicatedSCEVRewrites.end()) {
-    std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>> Rewrite =
-        I->second;
-    // Analysis was done before and failed to create an AddRec:
-    if (Rewrite.first == SymbolicPHI)
-      return None;
-    // Analysis was done before and succeeded to create an AddRec under
-    // a predicate:
-    assert(isa<SCEVAddRecExpr>(Rewrite.first) && "Expected an AddRec");
-    assert(!(Rewrite.second).empty() && "Expected to find Predicates");
-    return Rewrite;
-  }
-
-  Optional<std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>>>
-    Rewrite = createAddRecFromPHIWithCastsImpl(SymbolicPHI);
-
-  // Record in the cache that the analysis failed
-  if (!Rewrite) {
-    SmallVector<const SCEVPredicate *, 3> Predicates;
-    PredicatedSCEVRewrites[{SymbolicPHI, L}] = {SymbolicPHI, Predicates};
-    return None;
-  }
-
-  return Rewrite;
-}
-
-// FIXME: This utility is currently required because the Rewriter currently
-// does not rewrite this expression:
-// {0, +, (sext ix (trunc iy to ix) to iy)}
-// into {0, +, %step},
-// even when the following Equal predicate exists:
-// "%step == (sext ix (trunc iy to ix) to iy)".
-bool PredicatedScalarEvolution::areAddRecsEqualWithPreds(
-    const SCEVAddRecExpr *AR1, const SCEVAddRecExpr *AR2) const {
-  if (AR1 == AR2)
-    return true;
-
-  auto areExprsEqual = [&](const SCEV *Expr1, const SCEV *Expr2) -> bool {
-    if (Expr1 != Expr2 && !Preds.implies(SE.getEqualPredicate(Expr1, Expr2)) &&
-        !Preds.implies(SE.getEqualPredicate(Expr2, Expr1)))
-      return false;
-    return true;
-  };
-
-  if (!areExprsEqual(AR1->getStart(), AR2->getStart()) ||
-      !areExprsEqual(AR1->getStepRecurrence(SE), AR2->getStepRecurrence(SE)))
-    return false;
-  return true;
-}
-
-/// A helper function for createAddRecFromPHI to handle simple cases.
-///
-/// This function tries to find an AddRec expression for the simplest (yet most
-/// common) cases: PN = PHI(Start, OP(Self, LoopInvariant)).
-/// If it fails, createAddRecFromPHI will use a more general, but slow,
-/// technique for finding the AddRec expression.
-const SCEV *ScalarEvolution::createSimpleAffineAddRec(PHINode *PN,
-                                                      Value *BEValueV,
-                                                      Value *StartValueV) {
-  const Loop *L = LI.getLoopFor(PN->getParent());
-  assert(L && L->getHeader() == PN->getParent());
-  assert(BEValueV && StartValueV);
-
-  auto BO = MatchBinaryOp(BEValueV, DT);
-  if (!BO)
-    return nullptr;
-
-  if (BO->Opcode != Instruction::Add)
-    return nullptr;
-
-  const SCEV *Accum = nullptr;
-  if (BO->LHS == PN && L->isLoopInvariant(BO->RHS))
-    Accum = getSCEV(BO->RHS);
-  else if (BO->RHS == PN && L->isLoopInvariant(BO->LHS))
-    Accum = getSCEV(BO->LHS);
-
-  if (!Accum)
-    return nullptr;
-
-  SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap;
-  if (BO->IsNUW)
-    Flags = setFlags(Flags, SCEV::FlagNUW);
-  if (BO->IsNSW)
-    Flags = setFlags(Flags, SCEV::FlagNSW);
-
-  const SCEV *StartVal = getSCEV(StartValueV);
-  const SCEV *PHISCEV = getAddRecExpr(StartVal, Accum, L, Flags);
-
-  ValueExprMap[SCEVCallbackVH(PN, this)] = PHISCEV;
-
-  // We can add Flags to the post-inc expression only if we
-  // know that it is *undefined behavior* for BEValueV to
-  // overflow.
-  if (auto *BEInst = dyn_cast<Instruction>(BEValueV))
-    if (isLoopInvariant(Accum, L) && isAddRecNeverPoison(BEInst, L))
-      (void)getAddRecExpr(getAddExpr(StartVal, Accum), Accum, L, Flags);
-
-  return PHISCEV;
-}
-
-const SCEV *ScalarEvolution::createAddRecFromPHI(PHINode *PN) {
-  const Loop *L = LI.getLoopFor(PN->getParent());
-  if (!L || L->getHeader() != PN->getParent())
-    return nullptr;
-
-  // The loop may have multiple entrances or multiple exits; we can analyze
-  // this phi as an addrec if it has a unique entry value and a unique
-  // backedge value.
-  Value *BEValueV = nullptr, *StartValueV = nullptr;
-  for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
-    Value *V = PN->getIncomingValue(i);
-    if (L->contains(PN->getIncomingBlock(i))) {
-      if (!BEValueV) {
-        BEValueV = V;
-      } else if (BEValueV != V) {
-        BEValueV = nullptr;
-        break;
-      }
-    } else if (!StartValueV) {
-      StartValueV = V;
-    } else if (StartValueV != V) {
-      StartValueV = nullptr;
-      break;
-    }
-  }
-  if (!BEValueV || !StartValueV)
-    return nullptr;
-
-  assert(ValueExprMap.find_as(PN) == ValueExprMap.end() &&
-         "PHI node already processed?");
-
-  // First, try to find AddRec expression without creating a fictituos symbolic
-  // value for PN.
-  if (auto *S = createSimpleAffineAddRec(PN, BEValueV, StartValueV))
-    return S;
-
-  // Handle PHI node value symbolically.
-  const SCEV *SymbolicName = getUnknown(PN);
-  ValueExprMap.insert({SCEVCallbackVH(PN, this), SymbolicName});
-
-  // Using this symbolic name for the PHI, analyze the value coming around
-  // the back-edge.
-  const SCEV *BEValue = getSCEV(BEValueV);
-
-  // NOTE: If BEValue is loop invariant, we know that the PHI node just
-  // has a special value for the first iteration of the loop.
-
-  // If the value coming around the backedge is an add with the symbolic
-  // value we just inserted, then we found a simple induction variable!
-  if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(BEValue)) {
-    // If there is a single occurrence of the symbolic value, replace it
-    // with a recurrence.
-    unsigned FoundIndex = Add->getNumOperands();
-    for (unsigned i = 0, e = Add->getNumOperands(); i != e; ++i)
-      if (Add->getOperand(i) == SymbolicName)
-        if (FoundIndex == e) {
-          FoundIndex = i;
-          break;
-        }
-
-    if (FoundIndex != Add->getNumOperands()) {
-      // Create an add with everything but the specified operand.
-      SmallVector<const SCEV *, 8> Ops;
-      for (unsigned i = 0, e = Add->getNumOperands(); i != e; ++i)
-        if (i != FoundIndex)
-          Ops.push_back(SCEVBackedgeConditionFolder::rewrite(Add->getOperand(i),
-                                                             L, *this));
-      const SCEV *Accum = getAddExpr(Ops);
-
-      // This is not a valid addrec if the step amount is varying each
-      // loop iteration, but is not itself an addrec in this loop.
-      if (isLoopInvariant(Accum, L) ||
-          (isa<SCEVAddRecExpr>(Accum) &&
-           cast<SCEVAddRecExpr>(Accum)->getLoop() == L)) {
-        SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap;
-
-        if (auto BO = MatchBinaryOp(BEValueV, DT)) {
-          if (BO->Opcode == Instruction::Add && BO->LHS == PN) {
-            if (BO->IsNUW)
-              Flags = setFlags(Flags, SCEV::FlagNUW);
-            if (BO->IsNSW)
-              Flags = setFlags(Flags, SCEV::FlagNSW);
-          }
-        } else if (GEPOperator *GEP = dyn_cast<GEPOperator>(BEValueV)) {
-          // If the increment is an inbounds GEP, then we know the address
-          // space cannot be wrapped around. We cannot make any guarantee
-          // about signed or unsigned overflow because pointers are
-          // unsigned but we may have a negative index from the base
-          // pointer. We can guarantee that no unsigned wrap occurs if the
-          // indices form a positive value.
-          if (GEP->isInBounds() && GEP->getOperand(0) == PN) {
-            Flags = setFlags(Flags, SCEV::FlagNW);
-
-            const SCEV *Ptr = getSCEV(GEP->getPointerOperand());
-            if (isKnownPositive(getMinusSCEV(getSCEV(GEP), Ptr)))
-              Flags = setFlags(Flags, SCEV::FlagNUW);
-          }
-
-          // We cannot transfer nuw and nsw flags from subtraction
-          // operations -- sub nuw X, Y is not the same as add nuw X, -Y
-          // for instance.
-        }
-
-        const SCEV *StartVal = getSCEV(StartValueV);
-        const SCEV *PHISCEV = getAddRecExpr(StartVal, Accum, L, Flags);
-
-        // Okay, for the entire analysis of this edge we assumed the PHI
-        // to be symbolic.  We now need to go back and purge all of the
-        // entries for the scalars that use the symbolic expression.
-        forgetSymbolicName(PN, SymbolicName);
-        ValueExprMap[SCEVCallbackVH(PN, this)] = PHISCEV;
-
-        // We can add Flags to the post-inc expression only if we
-        // know that it is *undefined behavior* for BEValueV to
-        // overflow.
-        if (auto *BEInst = dyn_cast<Instruction>(BEValueV))
-          if (isLoopInvariant(Accum, L) && isAddRecNeverPoison(BEInst, L))
-            (void)getAddRecExpr(getAddExpr(StartVal, Accum), Accum, L, Flags);
-
-        return PHISCEV;
-      }
-    }
-  } else {
-    // Otherwise, this could be a loop like this:
-    //     i = 0;  for (j = 1; ..; ++j) { ....  i = j; }
-    // In this case, j = {1,+,1}  and BEValue is j.
-    // Because the other in-value of i (0) fits the evolution of BEValue
-    // i really is an addrec evolution.
-    //
-    // We can generalize this saying that i is the shifted value of BEValue
-    // by one iteration:
-    //   PHI(f(0), f({1,+,1})) --> f({0,+,1})
-    const SCEV *Shifted = SCEVShiftRewriter::rewrite(BEValue, L, *this);
-    const SCEV *Start = SCEVInitRewriter::rewrite(Shifted, L, *this, false);
-    if (Shifted != getCouldNotCompute() &&
-        Start != getCouldNotCompute()) {
-      const SCEV *StartVal = getSCEV(StartValueV);
-      if (Start == StartVal) {
-        // Okay, for the entire analysis of this edge we assumed the PHI
-        // to be symbolic.  We now need to go back and purge all of the
-        // entries for the scalars that use the symbolic expression.
-        forgetSymbolicName(PN, SymbolicName);
-        ValueExprMap[SCEVCallbackVH(PN, this)] = Shifted;
-        return Shifted;
-      }
-    }
-  }
-
-  // Remove the temporary PHI node SCEV that has been inserted while intending
-  // to create an AddRecExpr for this PHI node. We can not keep this temporary
-  // as it will prevent later (possibly simpler) SCEV expressions to be added
-  // to the ValueExprMap.
-  eraseValueFromMap(PN);
-
-  return nullptr;
-}
-
-// Checks if the SCEV S is available at BB.  S is considered available at BB
-// if S can be materialized at BB without introducing a fault.
-static bool IsAvailableOnEntry(const Loop *L, DominatorTree &DT, const SCEV *S,
-                               BasicBlock *BB) {
-  struct CheckAvailable {
-    bool TraversalDone = false;
-    bool Available = true;
-
-    const Loop *L = nullptr;  // The loop BB is in (can be nullptr)
-    BasicBlock *BB = nullptr;
-    DominatorTree &DT;
-
-    CheckAvailable(const Loop *L, BasicBlock *BB, DominatorTree &DT)
-      : L(L), BB(BB), DT(DT) {}
-
-    bool setUnavailable() {
-      TraversalDone = true;
-      Available = false;
-      return false;
-    }
-
-    bool follow(const SCEV *S) {
-      switch (S->getSCEVType()) {
-      case scConstant: case scTruncate: case scZeroExtend: case scSignExtend:
-      case scAddExpr: case scMulExpr: case scUMaxExpr: case scSMaxExpr:
-        // These expressions are available if their operand(s) is/are.
-        return true;
-
-      case scAddRecExpr: {
-        // We allow add recurrences that are on the loop BB is in, or some
-        // outer loop.  This guarantees availability because the value of the
-        // add recurrence at BB is simply the "current" value of the induction
-        // variable.  We can relax this in the future; for instance an add
-        // recurrence on a sibling dominating loop is also available at BB.
-        const auto *ARLoop = cast<SCEVAddRecExpr>(S)->getLoop();
-        if (L && (ARLoop == L || ARLoop->contains(L)))
-          return true;
-
-        return setUnavailable();
-      }
-
-      case scUnknown: {
-        // For SCEVUnknown, we check for simple dominance.
-        const auto *SU = cast<SCEVUnknown>(S);
-        Value *V = SU->getValue();
-
-        if (isa<Argument>(V))
-          return false;
-
-        if (isa<Instruction>(V) && DT.dominates(cast<Instruction>(V), BB))
-          return false;
-
-        return setUnavailable();
-      }
-
-      case scUDivExpr:
-      case scCouldNotCompute:
-        // We do not try to smart about these at all.
-        return setUnavailable();
-      }
-      llvm_unreachable("switch should be fully covered!");
-    }
-
-    bool isDone() { return TraversalDone; }
-  };
-
-  CheckAvailable CA(L, BB, DT);
-  SCEVTraversal<CheckAvailable> ST(CA);
-
-  ST.visitAll(S);
-  return CA.Available;
-}
-
-// Try to match a control flow sequence that branches out at BI and merges back
-// at Merge into a "C ? LHS : RHS" select pattern.  Return true on a successful
-// match.
-static bool BrPHIToSelect(DominatorTree &DT, BranchInst *BI, PHINode *Merge,
-                          Value *&C, Value *&LHS, Value *&RHS) {
-  C = BI->getCondition();
-
-  BasicBlockEdge LeftEdge(BI->getParent(), BI->getSuccessor(0));
-  BasicBlockEdge RightEdge(BI->getParent(), BI->getSuccessor(1));
-
-  if (!LeftEdge.isSingleEdge())
-    return false;
-
-  assert(RightEdge.isSingleEdge() && "Follows from LeftEdge.isSingleEdge()");
-
-  Use &LeftUse = Merge->getOperandUse(0);
-  Use &RightUse = Merge->getOperandUse(1);
-
-  if (DT.dominates(LeftEdge, LeftUse) && DT.dominates(RightEdge, RightUse)) {
-    LHS = LeftUse;
-    RHS = RightUse;
-    return true;
-  }
-
-  if (DT.dominates(LeftEdge, RightUse) && DT.dominates(RightEdge, LeftUse)) {
-    LHS = RightUse;
-    RHS = LeftUse;
-    return true;
-  }
-
-  return false;
-}
-
-const SCEV *ScalarEvolution::createNodeFromSelectLikePHI(PHINode *PN) {
-  auto IsReachable =
-      [&](BasicBlock *BB) { return DT.isReachableFromEntry(BB); };
-  if (PN->getNumIncomingValues() == 2 && all_of(PN->blocks(), IsReachable)) {
-    const Loop *L = LI.getLoopFor(PN->getParent());
-
-    // We don't want to break LCSSA, even in a SCEV expression tree.
-    for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
-      if (LI.getLoopFor(PN->getIncomingBlock(i)) != L)
-        return nullptr;
-
-    // Try to match
-    //
-    //  br %cond, label %left, label %right
-    // left:
-    //  br label %merge
-    // right:
-    //  br label %merge
-    // merge:
-    //  V = phi [ %x, %left ], [ %y, %right ]
-    //
-    // as "select %cond, %x, %y"
-
-    BasicBlock *IDom = DT[PN->getParent()]->getIDom()->getBlock();
-    assert(IDom && "At least the entry block should dominate PN");
-
-    auto *BI = dyn_cast<BranchInst>(IDom->getTerminator());
-    Value *Cond = nullptr, *LHS = nullptr, *RHS = nullptr;
-
-    if (BI && BI->isConditional() &&
-        BrPHIToSelect(DT, BI, PN, Cond, LHS, RHS) &&
-        IsAvailableOnEntry(L, DT, getSCEV(LHS), PN->getParent()) &&
-        IsAvailableOnEntry(L, DT, getSCEV(RHS), PN->getParent()))
-      return createNodeForSelectOrPHI(PN, Cond, LHS, RHS);
-  }
-
-  return nullptr;
-}
-
-const SCEV *ScalarEvolution::createNodeForPHI(PHINode *PN) {
-  if (const SCEV *S = createAddRecFromPHI(PN))
-    return S;
-
-  if (const SCEV *S = createNodeFromSelectLikePHI(PN))
-    return S;
-
-  // If the PHI has a single incoming value, follow that value, unless the
-  // PHI's incoming blocks are in a different loop, in which case doing so
-  // risks breaking LCSSA form. Instcombine would normally zap these, but
-  // it doesn't have DominatorTree information, so it may miss cases.
-  if (Value *V = SimplifyInstruction(PN, {getDataLayout(), &TLI, &DT, &AC}))
-    if (LI.replacementPreservesLCSSAForm(PN, V))
-      return getSCEV(V);
-
-  // If it's not a loop phi, we can't handle it yet.
-  return getUnknown(PN);
-}
-
-const SCEV *ScalarEvolution::createNodeForSelectOrPHI(Instruction *I,
-                                                      Value *Cond,
-                                                      Value *TrueVal,
-                                                      Value *FalseVal) {
-  // Handle "constant" branch or select. This can occur for instance when a
-  // loop pass transforms an inner loop and moves on to process the outer loop.
-  if (auto *CI = dyn_cast<ConstantInt>(Cond))
-    return getSCEV(CI->isOne() ? TrueVal : FalseVal);
-
-  // Try to match some simple smax or umax patterns.
-  auto *ICI = dyn_cast<ICmpInst>(Cond);
-  if (!ICI)
-    return getUnknown(I);
-
-  Value *LHS = ICI->getOperand(0);
-  Value *RHS = ICI->getOperand(1);
-
-  switch (ICI->getPredicate()) {
-  case ICmpInst::ICMP_SLT:
-  case ICmpInst::ICMP_SLE:
-    std::swap(LHS, RHS);
-    LLVM_FALLTHROUGH;
-  case ICmpInst::ICMP_SGT:
-  case ICmpInst::ICMP_SGE:
-    // a >s b ? a+x : b+x  ->  smax(a, b)+x
-    // a >s b ? b+x : a+x  ->  smin(a, b)+x
-    if (getTypeSizeInBits(LHS->getType()) <= getTypeSizeInBits(I->getType())) {
-      const SCEV *LS = getNoopOrSignExtend(getSCEV(LHS), I->getType());
-      const SCEV *RS = getNoopOrSignExtend(getSCEV(RHS), I->getType());
-      const SCEV *LA = getSCEV(TrueVal);
-      const SCEV *RA = getSCEV(FalseVal);
-      const SCEV *LDiff = getMinusSCEV(LA, LS);
-      const SCEV *RDiff = getMinusSCEV(RA, RS);
-      if (LDiff == RDiff)
-        return getAddExpr(getSMaxExpr(LS, RS), LDiff);
-      LDiff = getMinusSCEV(LA, RS);
-      RDiff = getMinusSCEV(RA, LS);
-      if (LDiff == RDiff)
-        return getAddExpr(getSMinExpr(LS, RS), LDiff);
-    }
-    break;
-  case ICmpInst::ICMP_ULT:
-  case ICmpInst::ICMP_ULE:
-    std::swap(LHS, RHS);
-    LLVM_FALLTHROUGH;
-  case ICmpInst::ICMP_UGT:
-  case ICmpInst::ICMP_UGE:
-    // a >u b ? a+x : b+x  ->  umax(a, b)+x
-    // a >u b ? b+x : a+x  ->  umin(a, b)+x
-    if (getTypeSizeInBits(LHS->getType()) <= getTypeSizeInBits(I->getType())) {
-      const SCEV *LS = getNoopOrZeroExtend(getSCEV(LHS), I->getType());
-      const SCEV *RS = getNoopOrZeroExtend(getSCEV(RHS), I->getType());
-      const SCEV *LA = getSCEV(TrueVal);
-      const SCEV *RA = getSCEV(FalseVal);
-      const SCEV *LDiff = getMinusSCEV(LA, LS);
-      const SCEV *RDiff = getMinusSCEV(RA, RS);
-      if (LDiff == RDiff)
-        return getAddExpr(getUMaxExpr(LS, RS), LDiff);
-      LDiff = getMinusSCEV(LA, RS);
-      RDiff = getMinusSCEV(RA, LS);
-      if (LDiff == RDiff)
-        return getAddExpr(getUMinExpr(LS, RS), LDiff);
-    }
-    break;
-  case ICmpInst::ICMP_NE:
-    // n != 0 ? n+x : 1+x  ->  umax(n, 1)+x
-    if (getTypeSizeInBits(LHS->getType()) <= getTypeSizeInBits(I->getType()) &&
-        isa<ConstantInt>(RHS) && cast<ConstantInt>(RHS)->isZero()) {
-      const SCEV *One = getOne(I->getType());
-      const SCEV *LS = getNoopOrZeroExtend(getSCEV(LHS), I->getType());
-      const SCEV *LA = getSCEV(TrueVal);
-      const SCEV *RA = getSCEV(FalseVal);
-      const SCEV *LDiff = getMinusSCEV(LA, LS);
-      const SCEV *RDiff = getMinusSCEV(RA, One);
-      if (LDiff == RDiff)
-        return getAddExpr(getUMaxExpr(One, LS), LDiff);
-    }
-    break;
-  case ICmpInst::ICMP_EQ:
-    // n == 0 ? 1+x : n+x  ->  umax(n, 1)+x
-    if (getTypeSizeInBits(LHS->getType()) <= getTypeSizeInBits(I->getType()) &&
-        isa<ConstantInt>(RHS) && cast<ConstantInt>(RHS)->isZero()) {
-      const SCEV *One = getOne(I->getType());
-      const SCEV *LS = getNoopOrZeroExtend(getSCEV(LHS), I->getType());
-      const SCEV *LA = getSCEV(TrueVal);
-      const SCEV *RA = getSCEV(FalseVal);
-      const SCEV *LDiff = getMinusSCEV(LA, One);
-      const SCEV *RDiff = getMinusSCEV(RA, LS);
-      if (LDiff == RDiff)
-        return getAddExpr(getUMaxExpr(One, LS), LDiff);
-    }
-    break;
-  default:
-    break;
-  }
-
-  return getUnknown(I);
-}
-
-/// Expand GEP instructions into add and multiply operations. This allows them
-/// to be analyzed by regular SCEV code.
-const SCEV *ScalarEvolution::createNodeForGEP(GEPOperator *GEP) {
-  // Don't attempt to analyze GEPs over unsized objects.
-  if (!GEP->getSourceElementType()->isSized())
-    return getUnknown(GEP);
-
-  SmallVector<const SCEV *, 4> IndexExprs;
-  for (auto Index = GEP->idx_begin(); Index != GEP->idx_end(); ++Index)
-    IndexExprs.push_back(getSCEV(*Index));
-  return getGEPExpr(GEP, IndexExprs);
-}
-
-uint32_t ScalarEvolution::GetMinTrailingZerosImpl(const SCEV *S) {
-  if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S))
-    return C->getAPInt().countTrailingZeros();
-
-  if (const SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(S))
-    return std::min(GetMinTrailingZeros(T->getOperand()),
-                    (uint32_t)getTypeSizeInBits(T->getType()));
-
-  if (const SCEVZeroExtendExpr *E = dyn_cast<SCEVZeroExtendExpr>(S)) {
-    uint32_t OpRes = GetMinTrailingZeros(E->getOperand());
-    return OpRes == getTypeSizeInBits(E->getOperand()->getType())
-               ? getTypeSizeInBits(E->getType())
-               : OpRes;
-  }
-
-  if (const SCEVSignExtendExpr *E = dyn_cast<SCEVSignExtendExpr>(S)) {
-    uint32_t OpRes = GetMinTrailingZeros(E->getOperand());
-    return OpRes == getTypeSizeInBits(E->getOperand()->getType())
-               ? getTypeSizeInBits(E->getType())
-               : OpRes;
-  }
-
-  if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(S)) {
-    // The result is the min of all operands results.
-    uint32_t MinOpRes = GetMinTrailingZeros(A->getOperand(0));
-    for (unsigned i = 1, e = A->getNumOperands(); MinOpRes && i != e; ++i)
-      MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(A->getOperand(i)));
-    return MinOpRes;
-  }
-
-  if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(S)) {
-    // The result is the sum of all operands results.
-    uint32_t SumOpRes = GetMinTrailingZeros(M->getOperand(0));
-    uint32_t BitWidth = getTypeSizeInBits(M->getType());
-    for (unsigned i = 1, e = M->getNumOperands();
-         SumOpRes != BitWidth && i != e; ++i)
-      SumOpRes =
-          std::min(SumOpRes + GetMinTrailingZeros(M->getOperand(i)), BitWidth);
-    return SumOpRes;
-  }
-
-  if (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(S)) {
-    // The result is the min of all operands results.
-    uint32_t MinOpRes = GetMinTrailingZeros(A->getOperand(0));
-    for (unsigned i = 1, e = A->getNumOperands(); MinOpRes && i != e; ++i)
-      MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(A->getOperand(i)));
-    return MinOpRes;
-  }
-
-  if (const SCEVSMaxExpr *M = dyn_cast<SCEVSMaxExpr>(S)) {
-    // The result is the min of all operands results.
-    uint32_t MinOpRes = GetMinTrailingZeros(M->getOperand(0));
-    for (unsigned i = 1, e = M->getNumOperands(); MinOpRes && i != e; ++i)
-      MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(M->getOperand(i)));
-    return MinOpRes;
-  }
-
-  if (const SCEVUMaxExpr *M = dyn_cast<SCEVUMaxExpr>(S)) {
-    // The result is the min of all operands results.
-    uint32_t MinOpRes = GetMinTrailingZeros(M->getOperand(0));
-    for (unsigned i = 1, e = M->getNumOperands(); MinOpRes && i != e; ++i)
-      MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(M->getOperand(i)));
-    return MinOpRes;
-  }
-
-  if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
-    // For a SCEVUnknown, ask ValueTracking.
-    KnownBits Known = computeKnownBits(U->getValue(), getDataLayout(), 0, &AC, nullptr, &DT);
-    return Known.countMinTrailingZeros();
-  }
-
-  // SCEVUDivExpr
-  return 0;
-}
-
-uint32_t ScalarEvolution::GetMinTrailingZeros(const SCEV *S) {
-  auto I = MinTrailingZerosCache.find(S);
-  if (I != MinTrailingZerosCache.end())
-    return I->second;
-
-  uint32_t Result = GetMinTrailingZerosImpl(S);
-  auto InsertPair = MinTrailingZerosCache.insert({S, Result});
-  assert(InsertPair.second && "Should insert a new key");
-  return InsertPair.first->second;
-}
-
-/// Helper method to assign a range to V from metadata present in the IR.
-static Optional<ConstantRange> GetRangeFromMetadata(Value *V) {
-  if (Instruction *I = dyn_cast<Instruction>(V))
-    if (MDNode *MD = I->getMetadata(LLVMContext::MD_range))
-      return getConstantRangeFromMetadata(*MD);
-
-  return None;
-}
-
-/// Determine the range for a particular SCEV.  If SignHint is
-/// HINT_RANGE_UNSIGNED (resp. HINT_RANGE_SIGNED) then getRange prefers ranges
-/// with a "cleaner" unsigned (resp. signed) representation.
-const ConstantRange &
-ScalarEvolution::getRangeRef(const SCEV *S,
-                             ScalarEvolution::RangeSignHint SignHint) {
-  DenseMap<const SCEV *, ConstantRange> &Cache =
-      SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED ? UnsignedRanges
-                                                       : SignedRanges;
-
-  // See if we've computed this range already.
-  DenseMap<const SCEV *, ConstantRange>::iterator I = Cache.find(S);
-  if (I != Cache.end())
-    return I->second;
-
-  if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S))
-    return setRange(C, SignHint, ConstantRange(C->getAPInt()));
-
-  unsigned BitWidth = getTypeSizeInBits(S->getType());
-  ConstantRange ConservativeResult(BitWidth, /*isFullSet=*/true);
-
-  // If the value has known zeros, the maximum value will have those known zeros
-  // as well.
-  uint32_t TZ = GetMinTrailingZeros(S);
-  if (TZ != 0) {
-    if (SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED)
-      ConservativeResult =
-          ConstantRange(APInt::getMinValue(BitWidth),
-                        APInt::getMaxValue(BitWidth).lshr(TZ).shl(TZ) + 1);
-    else
-      ConservativeResult = ConstantRange(
-          APInt::getSignedMinValue(BitWidth),
-          APInt::getSignedMaxValue(BitWidth).ashr(TZ).shl(TZ) + 1);
-  }
-
-  if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
-    ConstantRange X = getRangeRef(Add->getOperand(0), SignHint);
-    for (unsigned i = 1, e = Add->getNumOperands(); i != e; ++i)
-      X = X.add(getRangeRef(Add->getOperand(i), SignHint));
-    return setRange(Add, SignHint, ConservativeResult.intersectWith(X));
-  }
-
-  if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(S)) {
-    ConstantRange X = getRangeRef(Mul->getOperand(0), SignHint);
-    for (unsigned i = 1, e = Mul->getNumOperands(); i != e; ++i)
-      X = X.multiply(getRangeRef(Mul->getOperand(i), SignHint));
-    return setRange(Mul, SignHint, ConservativeResult.intersectWith(X));
-  }
-
-  if (const SCEVSMaxExpr *SMax = dyn_cast<SCEVSMaxExpr>(S)) {
-    ConstantRange X = getRangeRef(SMax->getOperand(0), SignHint);
-    for (unsigned i = 1, e = SMax->getNumOperands(); i != e; ++i)
-      X = X.smax(getRangeRef(SMax->getOperand(i), SignHint));
-    return setRange(SMax, SignHint, ConservativeResult.intersectWith(X));
-  }
-
-  if (const SCEVUMaxExpr *UMax = dyn_cast<SCEVUMaxExpr>(S)) {
-    ConstantRange X = getRangeRef(UMax->getOperand(0), SignHint);
-    for (unsigned i = 1, e = UMax->getNumOperands(); i != e; ++i)
-      X = X.umax(getRangeRef(UMax->getOperand(i), SignHint));
-    return setRange(UMax, SignHint, ConservativeResult.intersectWith(X));
-  }
-
-  if (const SCEVUDivExpr *UDiv = dyn_cast<SCEVUDivExpr>(S)) {
-    ConstantRange X = getRangeRef(UDiv->getLHS(), SignHint);
-    ConstantRange Y = getRangeRef(UDiv->getRHS(), SignHint);
-    return setRange(UDiv, SignHint,
-                    ConservativeResult.intersectWith(X.udiv(Y)));
-  }
-
-  if (const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(S)) {
-    ConstantRange X = getRangeRef(ZExt->getOperand(), SignHint);
-    return setRange(ZExt, SignHint,
-                    ConservativeResult.intersectWith(X.zeroExtend(BitWidth)));
-  }
-
-  if (const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(S)) {
-    ConstantRange X = getRangeRef(SExt->getOperand(), SignHint);
-    return setRange(SExt, SignHint,
-                    ConservativeResult.intersectWith(X.signExtend(BitWidth)));
-  }
-
-  if (const SCEVTruncateExpr *Trunc = dyn_cast<SCEVTruncateExpr>(S)) {
-    ConstantRange X = getRangeRef(Trunc->getOperand(), SignHint);
-    return setRange(Trunc, SignHint,
-                    ConservativeResult.intersectWith(X.truncate(BitWidth)));
-  }
-
-  if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(S)) {
-    // If there's no unsigned wrap, the value will never be less than its
-    // initial value.
-    if (AddRec->hasNoUnsignedWrap())
-      if (const SCEVConstant *C = dyn_cast<SCEVConstant>(AddRec->getStart()))
-        if (!C->getValue()->isZero())
-          ConservativeResult = ConservativeResult.intersectWith(
-              ConstantRange(C->getAPInt(), APInt(BitWidth, 0)));
-
-    // If there's no signed wrap, and all the operands have the same sign or
-    // zero, the value won't ever change sign.
-    if (AddRec->hasNoSignedWrap()) {
-      bool AllNonNeg = true;
-      bool AllNonPos = true;
-      for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i) {
-        if (!isKnownNonNegative(AddRec->getOperand(i))) AllNonNeg = false;
-        if (!isKnownNonPositive(AddRec->getOperand(i))) AllNonPos = false;
-      }
-      if (AllNonNeg)
-        ConservativeResult = ConservativeResult.intersectWith(
-          ConstantRange(APInt(BitWidth, 0),
-                        APInt::getSignedMinValue(BitWidth)));
-      else if (AllNonPos)
-        ConservativeResult = ConservativeResult.intersectWith(
-          ConstantRange(APInt::getSignedMinValue(BitWidth),
-                        APInt(BitWidth, 1)));
-    }
-
-    // TODO: non-affine addrec
-    if (AddRec->isAffine()) {
-      const SCEV *MaxBECount = getMaxBackedgeTakenCount(AddRec->getLoop());
-      if (!isa<SCEVCouldNotCompute>(MaxBECount) &&
-          getTypeSizeInBits(MaxBECount->getType()) <= BitWidth) {
-        auto RangeFromAffine = getRangeForAffineAR(
-            AddRec->getStart(), AddRec->getStepRecurrence(*this), MaxBECount,
-            BitWidth);
-        if (!RangeFromAffine.isFullSet())
-          ConservativeResult =
-              ConservativeResult.intersectWith(RangeFromAffine);
-
-        auto RangeFromFactoring = getRangeViaFactoring(
-            AddRec->getStart(), AddRec->getStepRecurrence(*this), MaxBECount,
-            BitWidth);
-        if (!RangeFromFactoring.isFullSet())
-          ConservativeResult =
-              ConservativeResult.intersectWith(RangeFromFactoring);
-      }
-    }
-
-    return setRange(AddRec, SignHint, std::move(ConservativeResult));
-  }
-
-  if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
-    // Check if the IR explicitly contains !range metadata.
-    Optional<ConstantRange> MDRange = GetRangeFromMetadata(U->getValue());
-    if (MDRange.hasValue())
-      ConservativeResult = ConservativeResult.intersectWith(MDRange.getValue());
-
-    // Split here to avoid paying the compile-time cost of calling both
-    // computeKnownBits and ComputeNumSignBits.  This restriction can be lifted
-    // if needed.
-    const DataLayout &DL = getDataLayout();
-    if (SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED) {
-      // For a SCEVUnknown, ask ValueTracking.
-      KnownBits Known = computeKnownBits(U->getValue(), DL, 0, &AC, nullptr, &DT);
-      if (Known.One != ~Known.Zero + 1)
-        ConservativeResult =
-            ConservativeResult.intersectWith(ConstantRange(Known.One,
-                                                           ~Known.Zero + 1));
-    } else {
-      assert(SignHint == ScalarEvolution::HINT_RANGE_SIGNED &&
-             "generalize as needed!");
-      unsigned NS = ComputeNumSignBits(U->getValue(), DL, 0, &AC, nullptr, &DT);
-      if (NS > 1)
-        ConservativeResult = ConservativeResult.intersectWith(
-            ConstantRange(APInt::getSignedMinValue(BitWidth).ashr(NS - 1),
-                          APInt::getSignedMaxValue(BitWidth).ashr(NS - 1) + 1));
-    }
-
-    // A range of Phi is a subset of union of all ranges of its input.
-    if (const PHINode *Phi = dyn_cast<PHINode>(U->getValue())) {
-      // Make sure that we do not run over cycled Phis.
-      if (PendingPhiRanges.insert(Phi).second) {
-        ConstantRange RangeFromOps(BitWidth, /*isFullSet=*/false);
-        for (auto &Op : Phi->operands()) {
-          auto OpRange = getRangeRef(getSCEV(Op), SignHint);
-          RangeFromOps = RangeFromOps.unionWith(OpRange);
-          // No point to continue if we already have a full set.
-          if (RangeFromOps.isFullSet())
-            break;
-        }
-        ConservativeResult = ConservativeResult.intersectWith(RangeFromOps);
-        bool Erased = PendingPhiRanges.erase(Phi);
-        assert(Erased && "Failed to erase Phi properly?");
-        (void) Erased;
-      }
-    }
-
-    return setRange(U, SignHint, std::move(ConservativeResult));
-  }
-
-  return setRange(S, SignHint, std::move(ConservativeResult));
-}
-
-// Given a StartRange, Step and MaxBECount for an expression compute a range of
-// values that the expression can take. Initially, the expression has a value
-// from StartRange and then is changed by Step up to MaxBECount times. Signed
-// argument defines if we treat Step as signed or unsigned.
-static ConstantRange getRangeForAffineARHelper(APInt Step,
-                                               const ConstantRange &StartRange,
-                                               const APInt &MaxBECount,
-                                               unsigned BitWidth, bool Signed) {
-  // If either Step or MaxBECount is 0, then the expression won't change, and we
-  // just need to return the initial range.
-  if (Step == 0 || MaxBECount == 0)
-    return StartRange;
-
-  // If we don't know anything about the initial value (i.e. StartRange is
-  // FullRange), then we don't know anything about the final range either.
-  // Return FullRange.
-  if (StartRange.isFullSet())
-    return ConstantRange(BitWidth, /* isFullSet = */ true);
-
-  // If Step is signed and negative, then we use its absolute value, but we also
-  // note that we're moving in the opposite direction.
-  bool Descending = Signed && Step.isNegative();
-
-  if (Signed)
-    // This is correct even for INT_SMIN. Let's look at i8 to illustrate this:
-    // abs(INT_SMIN) = abs(-128) = abs(0x80) = -0x80 = 0x80 = 128.
-    // This equations hold true due to the well-defined wrap-around behavior of
-    // APInt.
-    Step = Step.abs();
-
-  // Check if Offset is more than full span of BitWidth. If it is, the
-  // expression is guaranteed to overflow.
-  if (APInt::getMaxValue(StartRange.getBitWidth()).udiv(Step).ult(MaxBECount))
-    return ConstantRange(BitWidth, /* isFullSet = */ true);
-
-  // Offset is by how much the expression can change. Checks above guarantee no
-  // overflow here.
-  APInt Offset = Step * MaxBECount;
-
-  // Minimum value of the final range will match the minimal value of StartRange
-  // if the expression is increasing and will be decreased by Offset otherwise.
-  // Maximum value of the final range will match the maximal value of StartRange
-  // if the expression is decreasing and will be increased by Offset otherwise.
-  APInt StartLower = StartRange.getLower();
-  APInt StartUpper = StartRange.getUpper() - 1;
-  APInt MovedBoundary = Descending ? (StartLower - std::move(Offset))
-                                   : (StartUpper + std::move(Offset));
-
-  // It's possible that the new minimum/maximum value will fall into the initial
-  // range (due to wrap around). This means that the expression can take any
-  // value in this bitwidth, and we have to return full range.
-  if (StartRange.contains(MovedBoundary))
-    return ConstantRange(BitWidth, /* isFullSet = */ true);
-
-  APInt NewLower =
-      Descending ? std::move(MovedBoundary) : std::move(StartLower);
-  APInt NewUpper =
-      Descending ? std::move(StartUpper) : std::move(MovedBoundary);
-  NewUpper += 1;
-
-  // If we end up with full range, return a proper full range.
-  if (NewLower == NewUpper)
-    return ConstantRange(BitWidth, /* isFullSet = */ true);
-
-  // No overflow detected, return [StartLower, StartUpper + Offset + 1) range.
-  return ConstantRange(std::move(NewLower), std::move(NewUpper));
-}
-
-ConstantRange ScalarEvolution::getRangeForAffineAR(const SCEV *Start,
-                                                   const SCEV *Step,
-                                                   const SCEV *MaxBECount,
-                                                   unsigned BitWidth) {
-  assert(!isa<SCEVCouldNotCompute>(MaxBECount) &&
-         getTypeSizeInBits(MaxBECount->getType()) <= BitWidth &&
-         "Precondition!");
-
-  MaxBECount = getNoopOrZeroExtend(MaxBECount, Start->getType());
-  APInt MaxBECountValue = getUnsignedRangeMax(MaxBECount);
-
-  // First, consider step signed.
-  ConstantRange StartSRange = getSignedRange(Start);
-  ConstantRange StepSRange = getSignedRange(Step);
-
-  // If Step can be both positive and negative, we need to find ranges for the
-  // maximum absolute step values in both directions and union them.
-  ConstantRange SR =
-      getRangeForAffineARHelper(StepSRange.getSignedMin(), StartSRange,
-                                MaxBECountValue, BitWidth, /* Signed = */ true);
-  SR = SR.unionWith(getRangeForAffineARHelper(StepSRange.getSignedMax(),
-                                              StartSRange, MaxBECountValue,
-                                              BitWidth, /* Signed = */ true));
-
-  // Next, consider step unsigned.
-  ConstantRange UR = getRangeForAffineARHelper(
-      getUnsignedRangeMax(Step), getUnsignedRange(Start),
-      MaxBECountValue, BitWidth, /* Signed = */ false);
-
-  // Finally, intersect signed and unsigned ranges.
-  return SR.intersectWith(UR);
-}
-
-ConstantRange ScalarEvolution::getRangeViaFactoring(const SCEV *Start,
-                                                    const SCEV *Step,
-                                                    const SCEV *MaxBECount,
-                                                    unsigned BitWidth) {
-  //    RangeOf({C?A:B,+,C?P:Q}) == RangeOf(C?{A,+,P}:{B,+,Q})
-  // == RangeOf({A,+,P}) union RangeOf({B,+,Q})
-
-  struct SelectPattern {
-    Value *Condition = nullptr;
-    APInt TrueValue;
-    APInt FalseValue;
-
-    explicit SelectPattern(ScalarEvolution &SE, unsigned BitWidth,
-                           const SCEV *S) {
-      Optional<unsigned> CastOp;
-      APInt Offset(BitWidth, 0);
-
-      assert(SE.getTypeSizeInBits(S->getType()) == BitWidth &&
-             "Should be!");
-
-      // Peel off a constant offset:
-      if (auto *SA = dyn_cast<SCEVAddExpr>(S)) {
-        // In the future we could consider being smarter here and handle
-        // {Start+Step,+,Step} too.
-        if (SA->getNumOperands() != 2 || !isa<SCEVConstant>(SA->getOperand(0)))
-          return;
-
-        Offset = cast<SCEVConstant>(SA->getOperand(0))->getAPInt();
-        S = SA->getOperand(1);
-      }
-
-      // Peel off a cast operation
-      if (auto *SCast = dyn_cast<SCEVCastExpr>(S)) {
-        CastOp = SCast->getSCEVType();
-        S = SCast->getOperand();
-      }
-
-      using namespace llvm::PatternMatch;
-
-      auto *SU = dyn_cast<SCEVUnknown>(S);
-      const APInt *TrueVal, *FalseVal;
-      if (!SU ||
-          !match(SU->getValue(), m_Select(m_Value(Condition), m_APInt(TrueVal),
-                                          m_APInt(FalseVal)))) {
-        Condition = nullptr;
-        return;
-      }
-
-      TrueValue = *TrueVal;
-      FalseValue = *FalseVal;
-
-      // Re-apply the cast we peeled off earlier
-      if (CastOp.hasValue())
-        switch (*CastOp) {
-        default:
-          llvm_unreachable("Unknown SCEV cast type!");
-
-        case scTruncate:
-          TrueValue = TrueValue.trunc(BitWidth);
-          FalseValue = FalseValue.trunc(BitWidth);
-          break;
-        case scZeroExtend:
-          TrueValue = TrueValue.zext(BitWidth);
-          FalseValue = FalseValue.zext(BitWidth);
-          break;
-        case scSignExtend:
-          TrueValue = TrueValue.sext(BitWidth);
-          FalseValue = FalseValue.sext(BitWidth);
-          break;
-        }
-
-      // Re-apply the constant offset we peeled off earlier
-      TrueValue += Offset;
-      FalseValue += Offset;
-    }
-
-    bool isRecognized() { return Condition != nullptr; }
-  };
-
-  SelectPattern StartPattern(*this, BitWidth, Start);
-  if (!StartPattern.isRecognized())
-    return ConstantRange(BitWidth, /* isFullSet = */ true);
-
-  SelectPattern StepPattern(*this, BitWidth, Step);
-  if (!StepPattern.isRecognized())
-    return ConstantRange(BitWidth, /* isFullSet = */ true);
-
-  if (StartPattern.Condition != StepPattern.Condition) {
-    // We don't handle this case today; but we could, by considering four
-    // possibilities below instead of two. I'm not sure if there are cases where
-    // that will help over what getRange already does, though.
-    return ConstantRange(BitWidth, /* isFullSet = */ true);
-  }
-
-  // NB! Calling ScalarEvolution::getConstant is fine, but we should not try to
-  // construct arbitrary general SCEV expressions here.  This function is called
-  // from deep in the call stack, and calling getSCEV (on a sext instruction,
-  // say) can end up caching a suboptimal value.
-
-  // FIXME: without the explicit `this` receiver below, MSVC errors out with
-  // C2352 and C2512 (otherwise it isn't needed).
-
-  const SCEV *TrueStart = this->getConstant(StartPattern.TrueValue);
-  const SCEV *TrueStep = this->getConstant(StepPattern.TrueValue);
-  const SCEV *FalseStart = this->getConstant(StartPattern.FalseValue);
-  const SCEV *FalseStep = this->getConstant(StepPattern.FalseValue);
-
-  ConstantRange TrueRange =
-      this->getRangeForAffineAR(TrueStart, TrueStep, MaxBECount, BitWidth);
-  ConstantRange FalseRange =
-      this->getRangeForAffineAR(FalseStart, FalseStep, MaxBECount, BitWidth);
-
-  return TrueRange.unionWith(FalseRange);
-}
-
-SCEV::NoWrapFlags ScalarEvolution::getNoWrapFlagsFromUB(const Value *V) {
-  if (isa<ConstantExpr>(V)) return SCEV::FlagAnyWrap;
-  const BinaryOperator *BinOp = cast<BinaryOperator>(V);
-
-  // Return early if there are no flags to propagate to the SCEV.
-  SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap;
-  if (BinOp->hasNoUnsignedWrap())
-    Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNUW);
-  if (BinOp->hasNoSignedWrap())
-    Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNSW);
-  if (Flags == SCEV::FlagAnyWrap)
-    return SCEV::FlagAnyWrap;
-
-  return isSCEVExprNeverPoison(BinOp) ? Flags : SCEV::FlagAnyWrap;
-}
-
-bool ScalarEvolution::isSCEVExprNeverPoison(const Instruction *I) {
-  // Here we check that I is in the header of the innermost loop containing I,
-  // since we only deal with instructions in the loop header. The actual loop we
-  // need to check later will come from an add recurrence, but getting that
-  // requires computing the SCEV of the operands, which can be expensive. This
-  // check we can do cheaply to rule out some cases early.
-  Loop *InnermostContainingLoop = LI.getLoopFor(I->getParent());
-  if (InnermostContainingLoop == nullptr ||
-      InnermostContainingLoop->getHeader() != I->getParent())
-    return false;
-
-  // Only proceed if we can prove that I does not yield poison.
-  if (!programUndefinedIfFullPoison(I))
-    return false;
-
-  // At this point we know that if I is executed, then it does not wrap
-  // according to at least one of NSW or NUW. If I is not executed, then we do
-  // not know if the calculation that I represents would wrap. Multiple
-  // instructions can map to the same SCEV. If we apply NSW or NUW from I to
-  // the SCEV, we must guarantee no wrapping for that SCEV also when it is
-  // derived from other instructions that map to the same SCEV. We cannot make
-  // that guarantee for cases where I is not executed. So we need to find the
-  // loop that I is considered in relation to and prove that I is executed for
-  // every iteration of that loop. That implies that the value that I
-  // calculates does not wrap anywhere in the loop, so then we can apply the
-  // flags to the SCEV.
-  //
-  // We check isLoopInvariant to disambiguate in case we are adding recurrences
-  // from different loops, so that we know which loop to prove that I is
-  // executed in.
-  for (unsigned OpIndex = 0; OpIndex < I->getNumOperands(); ++OpIndex) {
-    // I could be an extractvalue from a call to an overflow intrinsic.
-    // TODO: We can do better here in some cases.
-    if (!isSCEVable(I->getOperand(OpIndex)->getType()))
-      return false;
-    const SCEV *Op = getSCEV(I->getOperand(OpIndex));
-    if (auto *AddRec = dyn_cast<SCEVAddRecExpr>(Op)) {
-      bool AllOtherOpsLoopInvariant = true;
-      for (unsigned OtherOpIndex = 0; OtherOpIndex < I->getNumOperands();
-           ++OtherOpIndex) {
-        if (OtherOpIndex != OpIndex) {
-          const SCEV *OtherOp = getSCEV(I->getOperand(OtherOpIndex));
-          if (!isLoopInvariant(OtherOp, AddRec->getLoop())) {
-            AllOtherOpsLoopInvariant = false;
-            break;
-          }
-        }
-      }
-      if (AllOtherOpsLoopInvariant &&
-          isGuaranteedToExecuteForEveryIteration(I, AddRec->getLoop()))
-        return true;
-    }
-  }
-  return false;
-}
-
-bool ScalarEvolution::isAddRecNeverPoison(const Instruction *I, const Loop *L) {
-  // If we know that \c I can never be poison period, then that's enough.
-  if (isSCEVExprNeverPoison(I))
-    return true;
-
-  // For an add recurrence specifically, we assume that infinite loops without
-  // side effects are undefined behavior, and then reason as follows:
-  //
-  // If the add recurrence is poison in any iteration, it is poison on all
-  // future iterations (since incrementing poison yields poison). If the result
-  // of the add recurrence is fed into the loop latch condition and the loop
-  // does not contain any throws or exiting blocks other than the latch, we now
-  // have the ability to "choose" whether the backedge is taken or not (by
-  // choosing a sufficiently evil value for the poison feeding into the branch)
-  // for every iteration including and after the one in which \p I first became
-  // poison.  There are two possibilities (let's call the iteration in which \p
-  // I first became poison as K):
-  //
-  //  1. In the set of iterations including and after K, the loop body executes
-  //     no side effects.  In this case executing the backege an infinte number
-  //     of times will yield undefined behavior.
-  //
-  //  2. In the set of iterations including and after K, the loop body executes
-  //     at least one side effect.  In this case, that specific instance of side
-  //     effect is control dependent on poison, which also yields undefined
-  //     behavior.
-
-  auto *ExitingBB = L->getExitingBlock();
-  auto *LatchBB = L->getLoopLatch();
-  if (!ExitingBB || !LatchBB || ExitingBB != LatchBB)
-    return false;
-
-  SmallPtrSet<const Instruction *, 16> Pushed;
-  SmallVector<const Instruction *, 8> PoisonStack;
-
-  // We start by assuming \c I, the post-inc add recurrence, is poison.  Only
-  // things that are known to be fully poison under that assumption go on the
-  // PoisonStack.
-  Pushed.insert(I);
-  PoisonStack.push_back(I);
-
-  bool LatchControlDependentOnPoison = false;
-  while (!PoisonStack.empty() && !LatchControlDependentOnPoison) {
-    const Instruction *Poison = PoisonStack.pop_back_val();
-
-    for (auto *PoisonUser : Poison->users()) {
-      if (propagatesFullPoison(cast<Instruction>(PoisonUser))) {
-        if (Pushed.insert(cast<Instruction>(PoisonUser)).second)
-          PoisonStack.push_back(cast<Instruction>(PoisonUser));
-      } else if (auto *BI = dyn_cast<BranchInst>(PoisonUser)) {
-        assert(BI->isConditional() && "Only possibility!");
-        if (BI->getParent() == LatchBB) {
-          LatchControlDependentOnPoison = true;
-          break;
-        }
-      }
-    }
-  }
-
-  return LatchControlDependentOnPoison && loopHasNoAbnormalExits(L);
-}
-
-ScalarEvolution::LoopProperties
-ScalarEvolution::getLoopProperties(const Loop *L) {
-  using LoopProperties = ScalarEvolution::LoopProperties;
-
-  auto Itr = LoopPropertiesCache.find(L);
-  if (Itr == LoopPropertiesCache.end()) {
-    auto HasSideEffects = [](Instruction *I) {
-      if (auto *SI = dyn_cast<StoreInst>(I))
-        return !SI->isSimple();
-
-      return I->mayHaveSideEffects();
-    };
-
-    LoopProperties LP = {/* HasNoAbnormalExits */ true,
-                         /*HasNoSideEffects*/ true};
-
-    for (auto *BB : L->getBlocks())
-      for (auto &I : *BB) {
-        if (!isGuaranteedToTransferExecutionToSuccessor(&I))
-          LP.HasNoAbnormalExits = false;
-        if (HasSideEffects(&I))
-          LP.HasNoSideEffects = false;
-        if (!LP.HasNoAbnormalExits && !LP.HasNoSideEffects)
-          break; // We're already as pessimistic as we can get.
-      }
-
-    auto InsertPair = LoopPropertiesCache.insert({L, LP});
-    assert(InsertPair.second && "We just checked!");
-    Itr = InsertPair.first;
-  }
-
-  return Itr->second;
-}
-
-const SCEV *ScalarEvolution::createSCEV(Value *V) {
-  if (!isSCEVable(V->getType()))
-    return getUnknown(V);
-
-  if (Instruction *I = dyn_cast<Instruction>(V)) {
-    // Don't attempt to analyze instructions in blocks that aren't
-    // reachable. Such instructions don't matter, and they aren't required
-    // to obey basic rules for definitions dominating uses which this
-    // analysis depends on.
-    if (!DT.isReachableFromEntry(I->getParent()))
-      return getUnknown(V);
-  } else if (ConstantInt *CI = dyn_cast<ConstantInt>(V))
-    return getConstant(CI);
-  else if (isa<ConstantPointerNull>(V))
-    return getZero(V->getType());
-  else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
-    return GA->isInterposable() ? getUnknown(V) : getSCEV(GA->getAliasee());
-  else if (!isa<ConstantExpr>(V))
-    return getUnknown(V);
-
-  Operator *U = cast<Operator>(V);
-  if (auto BO = MatchBinaryOp(U, DT)) {
-    switch (BO->Opcode) {
-    case Instruction::Add: {
-      // The simple thing to do would be to just call getSCEV on both operands
-      // and call getAddExpr with the result. However if we're looking at a
-      // bunch of things all added together, this can be quite inefficient,
-      // because it leads to N-1 getAddExpr calls for N ultimate operands.
-      // Instead, gather up all the operands and make a single getAddExpr call.
-      // LLVM IR canonical form means we need only traverse the left operands.
-      SmallVector<const SCEV *, 4> AddOps;
-      do {
-        if (BO->Op) {
-          if (auto *OpSCEV = getExistingSCEV(BO->Op)) {
-            AddOps.push_back(OpSCEV);
-            break;
-          }
-
-          // If a NUW or NSW flag can be applied to the SCEV for this
-          // addition, then compute the SCEV for this addition by itself
-          // with a separate call to getAddExpr. We need to do that
-          // instead of pushing the operands of the addition onto AddOps,
-          // since the flags are only known to apply to this particular
-          // addition - they may not apply to other additions that can be
-          // formed with operands from AddOps.
-          const SCEV *RHS = getSCEV(BO->RHS);
-          SCEV::NoWrapFlags Flags = getNoWrapFlagsFromUB(BO->Op);
-          if (Flags != SCEV::FlagAnyWrap) {
-            const SCEV *LHS = getSCEV(BO->LHS);
-            if (BO->Opcode == Instruction::Sub)
-              AddOps.push_back(getMinusSCEV(LHS, RHS, Flags));
-            else
-              AddOps.push_back(getAddExpr(LHS, RHS, Flags));
-            break;
-          }
-        }
-
-        if (BO->Opcode == Instruction::Sub)
-          AddOps.push_back(getNegativeSCEV(getSCEV(BO->RHS)));
-        else
-          AddOps.push_back(getSCEV(BO->RHS));
-
-        auto NewBO = MatchBinaryOp(BO->LHS, DT);
-        if (!NewBO || (NewBO->Opcode != Instruction::Add &&
-                       NewBO->Opcode != Instruction::Sub)) {
-          AddOps.push_back(getSCEV(BO->LHS));
-          break;
-        }
-        BO = NewBO;
-      } while (true);
-
-      return getAddExpr(AddOps);
-    }
-
-    case Instruction::Mul: {
-      SmallVector<const SCEV *, 4> MulOps;
-      do {
-        if (BO->Op) {
-          if (auto *OpSCEV = getExistingSCEV(BO->Op)) {
-            MulOps.push_back(OpSCEV);
-            break;
-          }
-
-          SCEV::NoWrapFlags Flags = getNoWrapFlagsFromUB(BO->Op);
-          if (Flags != SCEV::FlagAnyWrap) {
-            MulOps.push_back(
-                getMulExpr(getSCEV(BO->LHS), getSCEV(BO->RHS), Flags));
-            break;
-          }
-        }
-
-        MulOps.push_back(getSCEV(BO->RHS));
-        auto NewBO = MatchBinaryOp(BO->LHS, DT);
-        if (!NewBO || NewBO->Opcode != Instruction::Mul) {
-          MulOps.push_back(getSCEV(BO->LHS));
-          break;
-        }
-        BO = NewBO;
-      } while (true);
-
-      return getMulExpr(MulOps);
-    }
-    case Instruction::UDiv:
-      return getUDivExpr(getSCEV(BO->LHS), getSCEV(BO->RHS));
-    case Instruction::URem:
-      return getURemExpr(getSCEV(BO->LHS), getSCEV(BO->RHS));
-    case Instruction::Sub: {
-      SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap;
-      if (BO->Op)
-        Flags = getNoWrapFlagsFromUB(BO->Op);
-      return getMinusSCEV(getSCEV(BO->LHS), getSCEV(BO->RHS), Flags);
-    }
-    case Instruction::And:
-      // For an expression like x&255 that merely masks off the high bits,
-      // use zext(trunc(x)) as the SCEV expression.
-      if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->RHS)) {
-        if (CI->isZero())
-          return getSCEV(BO->RHS);
-        if (CI->isMinusOne())
-          return getSCEV(BO->LHS);
-        const APInt &A = CI->getValue();
-
-        // Instcombine's ShrinkDemandedConstant may strip bits out of
-        // constants, obscuring what would otherwise be a low-bits mask.
-        // Use computeKnownBits to compute what ShrinkDemandedConstant
-        // knew about to reconstruct a low-bits mask value.
-        unsigned LZ = A.countLeadingZeros();
-        unsigned TZ = A.countTrailingZeros();
-        unsigned BitWidth = A.getBitWidth();
-        KnownBits Known(BitWidth);
-        computeKnownBits(BO->LHS, Known, getDataLayout(),
-                         0, &AC, nullptr, &DT);
-
-        APInt EffectiveMask =
-            APInt::getLowBitsSet(BitWidth, BitWidth - LZ - TZ).shl(TZ);
-        if ((LZ != 0 || TZ != 0) && !((~A & ~Known.Zero) & EffectiveMask)) {
-          const SCEV *MulCount = getConstant(APInt::getOneBitSet(BitWidth, TZ));
-          const SCEV *LHS = getSCEV(BO->LHS);
-          const SCEV *ShiftedLHS = nullptr;
-          if (auto *LHSMul = dyn_cast<SCEVMulExpr>(LHS)) {
-            if (auto *OpC = dyn_cast<SCEVConstant>(LHSMul->getOperand(0))) {
-              // For an expression like (x * 8) & 8, simplify the multiply.
-              unsigned MulZeros = OpC->getAPInt().countTrailingZeros();
-              unsigned GCD = std::min(MulZeros, TZ);
-              APInt DivAmt = APInt::getOneBitSet(BitWidth, TZ - GCD);
-              SmallVector<const SCEV*, 4> MulOps;
-              MulOps.push_back(getConstant(OpC->getAPInt().lshr(GCD)));
-              MulOps.append(LHSMul->op_begin() + 1, LHSMul->op_end());
-              auto *NewMul = getMulExpr(MulOps, LHSMul->getNoWrapFlags());
-              ShiftedLHS = getUDivExpr(NewMul, getConstant(DivAmt));
-            }
-          }
-          if (!ShiftedLHS)
-            ShiftedLHS = getUDivExpr(LHS, MulCount);
-          return getMulExpr(
-              getZeroExtendExpr(
-                  getTruncateExpr(ShiftedLHS,
-                      IntegerType::get(getContext(), BitWidth - LZ - TZ)),
-                  BO->LHS->getType()),
-              MulCount);
-        }
-      }
-      break;
-
-    case Instruction::Or:
-      // If the RHS of the Or is a constant, we may have something like:
-      // X*4+1 which got turned into X*4|1.  Handle this as an Add so loop
-      // optimizations will transparently handle this case.
-      //
-      // In order for this transformation to be safe, the LHS must be of the
-      // form X*(2^n) and the Or constant must be less than 2^n.
-      if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->RHS)) {
-        const SCEV *LHS = getSCEV(BO->LHS);
-        const APInt &CIVal = CI->getValue();
-        if (GetMinTrailingZeros(LHS) >=
-            (CIVal.getBitWidth() - CIVal.countLeadingZeros())) {
-          // Build a plain add SCEV.
-          const SCEV *S = getAddExpr(LHS, getSCEV(CI));
-          // If the LHS of the add was an addrec and it has no-wrap flags,
-          // transfer the no-wrap flags, since an or won't introduce a wrap.
-          if (const SCEVAddRecExpr *NewAR = dyn_cast<SCEVAddRecExpr>(S)) {
-            const SCEVAddRecExpr *OldAR = cast<SCEVAddRecExpr>(LHS);
-            const_cast<SCEVAddRecExpr *>(NewAR)->setNoWrapFlags(
-                OldAR->getNoWrapFlags());
-          }
-          return S;
-        }
-      }
-      break;
-
-    case Instruction::Xor:
-      if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->RHS)) {
-        // If the RHS of xor is -1, then this is a not operation.
-        if (CI->isMinusOne())
-          return getNotSCEV(getSCEV(BO->LHS));
-
-        // Model xor(and(x, C), C) as and(~x, C), if C is a low-bits mask.
-        // This is a variant of the check for xor with -1, and it handles
-        // the case where instcombine has trimmed non-demanded bits out
-        // of an xor with -1.
-        if (auto *LBO = dyn_cast<BinaryOperator>(BO->LHS))
-          if (ConstantInt *LCI = dyn_cast<ConstantInt>(LBO->getOperand(1)))
-            if (LBO->getOpcode() == Instruction::And &&
-                LCI->getValue() == CI->getValue())
-              if (const SCEVZeroExtendExpr *Z =
-                      dyn_cast<SCEVZeroExtendExpr>(getSCEV(BO->LHS))) {
-                Type *UTy = BO->LHS->getType();
-                const SCEV *Z0 = Z->getOperand();
-                Type *Z0Ty = Z0->getType();
-                unsigned Z0TySize = getTypeSizeInBits(Z0Ty);
-
-                // If C is a low-bits mask, the zero extend is serving to
-                // mask off the high bits. Complement the operand and
-                // re-apply the zext.
-                if (CI->getValue().isMask(Z0TySize))
-                  return getZeroExtendExpr(getNotSCEV(Z0), UTy);
-
-                // If C is a single bit, it may be in the sign-bit position
-                // before the zero-extend. In this case, represent the xor
-                // using an add, which is equivalent, and re-apply the zext.
-                APInt Trunc = CI->getValue().trunc(Z0TySize);
-                if (Trunc.zext(getTypeSizeInBits(UTy)) == CI->getValue() &&
-                    Trunc.isSignMask())
-                  return getZeroExtendExpr(getAddExpr(Z0, getConstant(Trunc)),
-                                           UTy);
-              }
-      }
-      break;
-
-    case Instruction::Shl:
-      // Turn shift left of a constant amount into a multiply.
-      if (ConstantInt *SA = dyn_cast<ConstantInt>(BO->RHS)) {
-        uint32_t BitWidth = cast<IntegerType>(SA->getType())->getBitWidth();
-
-        // If the shift count is not less than the bitwidth, the result of
-        // the shift is undefined. Don't try to analyze it, because the
-        // resolution chosen here may differ from the resolution chosen in
-        // other parts of the compiler.
-        if (SA->getValue().uge(BitWidth))
-          break;
-
-        // It is currently not resolved how to interpret NSW for left
-        // shift by BitWidth - 1, so we avoid applying flags in that
-        // case. Remove this check (or this comment) once the situation
-        // is resolved. See
-        // http://lists.llvm.org/pipermail/llvm-dev/2015-April/084195.html
-        // and http://reviews.llvm.org/D8890 .
-        auto Flags = SCEV::FlagAnyWrap;
-        if (BO->Op && SA->getValue().ult(BitWidth - 1))
-          Flags = getNoWrapFlagsFromUB(BO->Op);
-
-        Constant *X = ConstantInt::get(
-            getContext(), APInt::getOneBitSet(BitWidth, SA->getZExtValue()));
-        return getMulExpr(getSCEV(BO->LHS), getSCEV(X), Flags);
-      }
-      break;
-
-    case Instruction::AShr: {
-      // AShr X, C, where C is a constant.
-      ConstantInt *CI = dyn_cast<ConstantInt>(BO->RHS);
-      if (!CI)
-        break;
-
-      Type *OuterTy = BO->LHS->getType();
-      uint64_t BitWidth = getTypeSizeInBits(OuterTy);
-      // If the shift count is not less than the bitwidth, the result of
-      // the shift is undefined. Don't try to analyze it, because the
-      // resolution chosen here may differ from the resolution chosen in
-      // other parts of the compiler.
-      if (CI->getValue().uge(BitWidth))
-        break;
-
-      if (CI->isZero())
-        return getSCEV(BO->LHS); // shift by zero --> noop
-
-      uint64_t AShrAmt = CI->getZExtValue();
-      Type *TruncTy = IntegerType::get(getContext(), BitWidth - AShrAmt);
-
-      Operator *L = dyn_cast<Operator>(BO->LHS);
-      if (L && L->getOpcode() == Instruction::Shl) {
-        // X = Shl A, n
-        // Y = AShr X, m
-        // Both n and m are constant.
-
-        const SCEV *ShlOp0SCEV = getSCEV(L->getOperand(0));
-        if (L->getOperand(1) == BO->RHS)
-          // For a two-shift sext-inreg, i.e. n = m,
-          // use sext(trunc(x)) as the SCEV expression.
-          return getSignExtendExpr(
-              getTruncateExpr(ShlOp0SCEV, TruncTy), OuterTy);
-
-        ConstantInt *ShlAmtCI = dyn_cast<ConstantInt>(L->getOperand(1));
-        if (ShlAmtCI && ShlAmtCI->getValue().ult(BitWidth)) {
-          uint64_t ShlAmt = ShlAmtCI->getZExtValue();
-          if (ShlAmt > AShrAmt) {
-            // When n > m, use sext(mul(trunc(x), 2^(n-m)))) as the SCEV
-            // expression. We already checked that ShlAmt < BitWidth, so
-            // the multiplier, 1 << (ShlAmt - AShrAmt), fits into TruncTy as
-            // ShlAmt - AShrAmt < Amt.
-            APInt Mul = APInt::getOneBitSet(BitWidth - AShrAmt,
-                                            ShlAmt - AShrAmt);
-            return getSignExtendExpr(
-                getMulExpr(getTruncateExpr(ShlOp0SCEV, TruncTy),
-                getConstant(Mul)), OuterTy);
-          }
-        }
-      }
-      break;
-    }
-    }
-  }
-
-  switch (U->getOpcode()) {
-  case Instruction::Trunc:
-    return getTruncateExpr(getSCEV(U->getOperand(0)), U->getType());
-
-  case Instruction::ZExt:
-    return getZeroExtendExpr(getSCEV(U->getOperand(0)), U->getType());
-
-  case Instruction::SExt:
-    if (auto BO = MatchBinaryOp(U->getOperand(0), DT)) {
-      // The NSW flag of a subtract does not always survive the conversion to
-      // A + (-1)*B.  By pushing sign extension onto its operands we are much
-      // more likely to preserve NSW and allow later AddRec optimisations.
-      //
-      // NOTE: This is effectively duplicating this logic from getSignExtend:
-      //   sext((A + B + ...)<nsw>) --> (sext(A) + sext(B) + ...)<nsw>
-      // but by that point the NSW information has potentially been lost.
-      if (BO->Opcode == Instruction::Sub && BO->IsNSW) {
-        Type *Ty = U->getType();
-        auto *V1 = getSignExtendExpr(getSCEV(BO->LHS), Ty);
-        auto *V2 = getSignExtendExpr(getSCEV(BO->RHS), Ty);
-        return getMinusSCEV(V1, V2, SCEV::FlagNSW);
-      }
-    }
-    return getSignExtendExpr(getSCEV(U->getOperand(0)), U->getType());
-
-  case Instruction::BitCast:
-    // BitCasts are no-op casts so we just eliminate the cast.
-    if (isSCEVable(U->getType()) && isSCEVable(U->getOperand(0)->getType()))
-      return getSCEV(U->getOperand(0));
-    break;
-
-  // It's tempting to handle inttoptr and ptrtoint as no-ops, however this can
-  // lead to pointer expressions which cannot safely be expanded to GEPs,
-  // because ScalarEvolution doesn't respect the GEP aliasing rules when
-  // simplifying integer expressions.
-
-  case Instruction::GetElementPtr:
-    return createNodeForGEP(cast<GEPOperator>(U));
-
-  case Instruction::PHI:
-    return createNodeForPHI(cast<PHINode>(U));
-
-  case Instruction::Select:
-    // U can also be a select constant expr, which let fall through.  Since
-    // createNodeForSelect only works for a condition that is an `ICmpInst`, and
-    // constant expressions cannot have instructions as operands, we'd have
-    // returned getUnknown for a select constant expressions anyway.
-    if (isa<Instruction>(U))
-      return createNodeForSelectOrPHI(cast<Instruction>(U), U->getOperand(0),
-                                      U->getOperand(1), U->getOperand(2));
-    break;
-
-  case Instruction::Call:
-  case Instruction::Invoke:
-    if (Value *RV = CallSite(U).getReturnedArgOperand())
-      return getSCEV(RV);
-    break;
-  }
-
-  return getUnknown(V);
-}
-
-//===----------------------------------------------------------------------===//
-//                   Iteration Count Computation Code
-//
-
-static unsigned getConstantTripCount(const SCEVConstant *ExitCount) {
-  if (!ExitCount)
-    return 0;
-
-  ConstantInt *ExitConst = ExitCount->getValue();
-
-  // Guard against huge trip counts.
-  if (ExitConst->getValue().getActiveBits() > 32)
-    return 0;
-
-  // In case of integer overflow, this returns 0, which is correct.
-  return ((unsigned)ExitConst->getZExtValue()) + 1;
-}
-
-unsigned ScalarEvolution::getSmallConstantTripCount(const Loop *L) {
-  if (BasicBlock *ExitingBB = L->getExitingBlock())
-    return getSmallConstantTripCount(L, ExitingBB);
-
-  // No trip count information for multiple exits.
-  return 0;
-}
-
-unsigned ScalarEvolution::getSmallConstantTripCount(const Loop *L,
-                                                    BasicBlock *ExitingBlock) {
-  assert(ExitingBlock && "Must pass a non-null exiting block!");
-  assert(L->isLoopExiting(ExitingBlock) &&
-         "Exiting block must actually branch out of the loop!");
-  const SCEVConstant *ExitCount =
-      dyn_cast<SCEVConstant>(getExitCount(L, ExitingBlock));
-  return getConstantTripCount(ExitCount);
-}
-
-unsigned ScalarEvolution::getSmallConstantMaxTripCount(const Loop *L) {
-  const auto *MaxExitCount =
-      dyn_cast<SCEVConstant>(getMaxBackedgeTakenCount(L));
-  return getConstantTripCount(MaxExitCount);
-}
-
-unsigned ScalarEvolution::getSmallConstantTripMultiple(const Loop *L) {
-  if (BasicBlock *ExitingBB = L->getExitingBlock())
-    return getSmallConstantTripMultiple(L, ExitingBB);
-
-  // No trip multiple information for multiple exits.
-  return 0;
-}
-
-/// Returns the largest constant divisor of the trip count of this loop as a
-/// normal unsigned value, if possible. This means that the actual trip count is
-/// always a multiple of the returned value (don't forget the trip count could
-/// very well be zero as well!).
-///
-/// Returns 1 if the trip count is unknown or not guaranteed to be the
-/// multiple of a constant (which is also the case if the trip count is simply
-/// constant, use getSmallConstantTripCount for that case), Will also return 1
-/// if the trip count is very large (>= 2^32).
-///
-/// As explained in the comments for getSmallConstantTripCount, this assumes
-/// that control exits the loop via ExitingBlock.
-unsigned
-ScalarEvolution::getSmallConstantTripMultiple(const Loop *L,
-                                              BasicBlock *ExitingBlock) {
-  assert(ExitingBlock && "Must pass a non-null exiting block!");
-  assert(L->isLoopExiting(ExitingBlock) &&
-         "Exiting block must actually branch out of the loop!");
-  const SCEV *ExitCount = getExitCount(L, ExitingBlock);
-  if (ExitCount == getCouldNotCompute())
-    return 1;
-
-  // Get the trip count from the BE count by adding 1.
-  const SCEV *TCExpr = getAddExpr(ExitCount, getOne(ExitCount->getType()));
-
-  const SCEVConstant *TC = dyn_cast<SCEVConstant>(TCExpr);
-  if (!TC)
-    // Attempt to factor more general cases. Returns the greatest power of
-    // two divisor. If overflow happens, the trip count expression is still
-    // divisible by the greatest power of 2 divisor returned.
-    return 1U << std::min((uint32_t)31, GetMinTrailingZeros(TCExpr));
-
-  ConstantInt *Result = TC->getValue();
-
-  // Guard against huge trip counts (this requires checking
-  // for zero to handle the case where the trip count == -1 and the
-  // addition wraps).
-  if (!Result || Result->getValue().getActiveBits() > 32 ||
-      Result->getValue().getActiveBits() == 0)
-    return 1;
-
-  return (unsigned)Result->getZExtValue();
-}
-
-/// Get the expression for the number of loop iterations for which this loop is
-/// guaranteed not to exit via ExitingBlock. Otherwise return
-/// SCEVCouldNotCompute.
-const SCEV *ScalarEvolution::getExitCount(const Loop *L,
-                                          BasicBlock *ExitingBlock) {
-  return getBackedgeTakenInfo(L).getExact(ExitingBlock, this);
-}
-
-const SCEV *
-ScalarEvolution::getPredicatedBackedgeTakenCount(const Loop *L,
-                                                 SCEVUnionPredicate &Preds) {
-  return getPredicatedBackedgeTakenInfo(L).getExact(L, this, &Preds);
-}
-
-const SCEV *ScalarEvolution::getBackedgeTakenCount(const Loop *L) {
-  return getBackedgeTakenInfo(L).getExact(L, this);
-}
-
-/// Similar to getBackedgeTakenCount, except return the least SCEV value that is
-/// known never to be less than the actual backedge taken count.
-const SCEV *ScalarEvolution::getMaxBackedgeTakenCount(const Loop *L) {
-  return getBackedgeTakenInfo(L).getMax(this);
-}
-
-bool ScalarEvolution::isBackedgeTakenCountMaxOrZero(const Loop *L) {
-  return getBackedgeTakenInfo(L).isMaxOrZero(this);
-}
-
-/// Push PHI nodes in the header of the given loop onto the given Worklist.
-static void
-PushLoopPHIs(const Loop *L, SmallVectorImpl<Instruction *> &Worklist) {
-  BasicBlock *Header = L->getHeader();
-
-  // Push all Loop-header PHIs onto the Worklist stack.
-  for (PHINode &PN : Header->phis())
-    Worklist.push_back(&PN);
-}
-
-const ScalarEvolution::BackedgeTakenInfo &
-ScalarEvolution::getPredicatedBackedgeTakenInfo(const Loop *L) {
-  auto &BTI = getBackedgeTakenInfo(L);
-  if (BTI.hasFullInfo())
-    return BTI;
-
-  auto Pair = PredicatedBackedgeTakenCounts.insert({L, BackedgeTakenInfo()});
-
-  if (!Pair.second)
-    return Pair.first->second;
-
-  BackedgeTakenInfo Result =
-      computeBackedgeTakenCount(L, /*AllowPredicates=*/true);
-
-  return PredicatedBackedgeTakenCounts.find(L)->second = std::move(Result);
-}
-
-const ScalarEvolution::BackedgeTakenInfo &
-ScalarEvolution::getBackedgeTakenInfo(const Loop *L) {
-  // Initially insert an invalid entry for this loop. If the insertion
-  // succeeds, proceed to actually compute a backedge-taken count and
-  // update the value. The temporary CouldNotCompute value tells SCEV
-  // code elsewhere that it shouldn't attempt to request a new
-  // backedge-taken count, which could result in infinite recursion.
-  std::pair<DenseMap<const Loop *, BackedgeTakenInfo>::iterator, bool> Pair =
-      BackedgeTakenCounts.insert({L, BackedgeTakenInfo()});
-  if (!Pair.second)
-    return Pair.first->second;
-
-  // computeBackedgeTakenCount may allocate memory for its result. Inserting it
-  // into the BackedgeTakenCounts map transfers ownership. Otherwise, the result
-  // must be cleared in this scope.
-  BackedgeTakenInfo Result = computeBackedgeTakenCount(L);
-
-  // In product build, there are no usage of statistic.
-  (void)NumTripCountsComputed;
-  (void)NumTripCountsNotComputed;
-#if LLVM_ENABLE_STATS || !defined(NDEBUG)
-  const SCEV *BEExact = Result.getExact(L, this);
-  if (BEExact != getCouldNotCompute()) {
-    assert(isLoopInvariant(BEExact, L) &&
-           isLoopInvariant(Result.getMax(this), L) &&
-           "Computed backedge-taken count isn't loop invariant for loop!");
-    ++NumTripCountsComputed;
-  }
-  else if (Result.getMax(this) == getCouldNotCompute() &&
-           isa<PHINode>(L->getHeader()->begin())) {
-    // Only count loops that have phi nodes as not being computable.
-    ++NumTripCountsNotComputed;
-  }
-#endif // LLVM_ENABLE_STATS || !defined(NDEBUG)
-
-  // Now that we know more about the trip count for this loop, forget any
-  // existing SCEV values for PHI nodes in this loop since they are only
-  // conservative estimates made without the benefit of trip count
-  // information. This is similar to the code in forgetLoop, except that
-  // it handles SCEVUnknown PHI nodes specially.
-  if (Result.hasAnyInfo()) {
-    SmallVector<Instruction *, 16> Worklist;
-    PushLoopPHIs(L, Worklist);
-
-    SmallPtrSet<Instruction *, 8> Discovered;
-    while (!Worklist.empty()) {
-      Instruction *I = Worklist.pop_back_val();
-
-      ValueExprMapType::iterator It =
-        ValueExprMap.find_as(static_cast<Value *>(I));
-      if (It != ValueExprMap.end()) {
-        const SCEV *Old = It->second;
-
-        // SCEVUnknown for a PHI either means that it has an unrecognized
-        // structure, or it's a PHI that's in the progress of being computed
-        // by createNodeForPHI.  In the former case, additional loop trip
-        // count information isn't going to change anything. In the later
-        // case, createNodeForPHI will perform the necessary updates on its
-        // own when it gets to that point.
-        if (!isa<PHINode>(I) || !isa<SCEVUnknown>(Old)) {
-          eraseValueFromMap(It->first);
-          forgetMemoizedResults(Old);
-        }
-        if (PHINode *PN = dyn_cast<PHINode>(I))
-          ConstantEvolutionLoopExitValue.erase(PN);
-      }
-
-      // Since we don't need to invalidate anything for correctness and we're
-      // only invalidating to make SCEV's results more precise, we get to stop
-      // early to avoid invalidating too much.  This is especially important in
-      // cases like:
-      //
-      //   %v = f(pn0, pn1) // pn0 and pn1 used through some other phi node
-      // loop0:
-      //   %pn0 = phi
-      //   ...
-      // loop1:
-      //   %pn1 = phi
-      //   ...
-      //
-      // where both loop0 and loop1's backedge taken count uses the SCEV
-      // expression for %v.  If we don't have the early stop below then in cases
-      // like the above, getBackedgeTakenInfo(loop1) will clear out the trip
-      // count for loop0 and getBackedgeTakenInfo(loop0) will clear out the trip
-      // count for loop1, effectively nullifying SCEV's trip count cache.
-      for (auto *U : I->users())
-        if (auto *I = dyn_cast<Instruction>(U)) {
-          auto *LoopForUser = LI.getLoopFor(I->getParent());
-          if (LoopForUser && L->contains(LoopForUser) &&
-              Discovered.insert(I).second)
-            Worklist.push_back(I);
-        }
-    }
-  }
-
-  // Re-lookup the insert position, since the call to
-  // computeBackedgeTakenCount above could result in a
-  // recusive call to getBackedgeTakenInfo (on a different
-  // loop), which would invalidate the iterator computed
-  // earlier.
-  return BackedgeTakenCounts.find(L)->second = std::move(Result);
-}
-
-void ScalarEvolution::forgetLoop(const Loop *L) {
-  // Drop any stored trip count value.
-  auto RemoveLoopFromBackedgeMap =
-      [](DenseMap<const Loop *, BackedgeTakenInfo> &Map, const Loop *L) {
-        auto BTCPos = Map.find(L);
-        if (BTCPos != Map.end()) {
-          BTCPos->second.clear();
-          Map.erase(BTCPos);
-        }
-      };
-
-  SmallVector<const Loop *, 16> LoopWorklist(1, L);
-  SmallVector<Instruction *, 32> Worklist;
-  SmallPtrSet<Instruction *, 16> Visited;
-
-  // Iterate over all the loops and sub-loops to drop SCEV information.
-  while (!LoopWorklist.empty()) {
-    auto *CurrL = LoopWorklist.pop_back_val();
-
-    RemoveLoopFromBackedgeMap(BackedgeTakenCounts, CurrL);
-    RemoveLoopFromBackedgeMap(PredicatedBackedgeTakenCounts, CurrL);
-
-    // Drop information about predicated SCEV rewrites for this loop.
-    for (auto I = PredicatedSCEVRewrites.begin();
-         I != PredicatedSCEVRewrites.end();) {
-      std::pair<const SCEV *, const Loop *> Entry = I->first;
-      if (Entry.second == CurrL)
-        PredicatedSCEVRewrites.erase(I++);
-      else
-        ++I;
-    }
-
-    auto LoopUsersItr = LoopUsers.find(CurrL);
-    if (LoopUsersItr != LoopUsers.end()) {
-      for (auto *S : LoopUsersItr->second)
-        forgetMemoizedResults(S);
-      LoopUsers.erase(LoopUsersItr);
-    }
-
-    // Drop information about expressions based on loop-header PHIs.
-    PushLoopPHIs(CurrL, Worklist);
-
-    while (!Worklist.empty()) {
-      Instruction *I = Worklist.pop_back_val();
-      if (!Visited.insert(I).second)
-        continue;
-
-      ValueExprMapType::iterator It =
-          ValueExprMap.find_as(static_cast<Value *>(I));
-      if (It != ValueExprMap.end()) {
-        eraseValueFromMap(It->first);
-        forgetMemoizedResults(It->second);
-        if (PHINode *PN = dyn_cast<PHINode>(I))
-          ConstantEvolutionLoopExitValue.erase(PN);
-      }
-
-      PushDefUseChildren(I, Worklist);
-    }
-
-    LoopPropertiesCache.erase(CurrL);
-    // Forget all contained loops too, to avoid dangling entries in the
-    // ValuesAtScopes map.
-    LoopWorklist.append(CurrL->begin(), CurrL->end());
-  }
-}
-
-void ScalarEvolution::forgetTopmostLoop(const Loop *L) {
-  while (Loop *Parent = L->getParentLoop())
-    L = Parent;
-  forgetLoop(L);
-}
-
-void ScalarEvolution::forgetValue(Value *V) {
-  Instruction *I = dyn_cast<Instruction>(V);
-  if (!I) return;
-
-  // Drop information about expressions based on loop-header PHIs.
-  SmallVector<Instruction *, 16> Worklist;
-  Worklist.push_back(I);
-
-  SmallPtrSet<Instruction *, 8> Visited;
-  while (!Worklist.empty()) {
-    I = Worklist.pop_back_val();
-    if (!Visited.insert(I).second)
-      continue;
-
-    ValueExprMapType::iterator It =
-      ValueExprMap.find_as(static_cast<Value *>(I));
-    if (It != ValueExprMap.end()) {
-      eraseValueFromMap(It->first);
-      forgetMemoizedResults(It->second);
-      if (PHINode *PN = dyn_cast<PHINode>(I))
-        ConstantEvolutionLoopExitValue.erase(PN);
-    }
-
-    PushDefUseChildren(I, Worklist);
-  }
-}
-
-/// Get the exact loop backedge taken count considering all loop exits. A
-/// computable result can only be returned for loops with all exiting blocks
-/// dominating the latch. howFarToZero assumes that the limit of each loop test
-/// is never skipped. This is a valid assumption as long as the loop exits via
-/// that test. For precise results, it is the caller's responsibility to specify
-/// the relevant loop exiting block using getExact(ExitingBlock, SE).
-const SCEV *
-ScalarEvolution::BackedgeTakenInfo::getExact(const Loop *L, ScalarEvolution *SE,
-                                             SCEVUnionPredicate *Preds) const {
-  // If any exits were not computable, the loop is not computable.
-  if (!isComplete() || ExitNotTaken.empty())
-    return SE->getCouldNotCompute();
-
-  const BasicBlock *Latch = L->getLoopLatch();
-  // All exiting blocks we have collected must dominate the only backedge.
-  if (!Latch)
-    return SE->getCouldNotCompute();
-
-  // All exiting blocks we have gathered dominate loop's latch, so exact trip
-  // count is simply a minimum out of all these calculated exit counts.
-  SmallVector<const SCEV *, 2> Ops;
-  for (auto &ENT : ExitNotTaken) {
-    const SCEV *BECount = ENT.ExactNotTaken;
-    assert(BECount != SE->getCouldNotCompute() && "Bad exit SCEV!");
-    assert(SE->DT.dominates(ENT.ExitingBlock, Latch) &&
-           "We should only have known counts for exiting blocks that dominate "
-           "latch!");
-
-    Ops.push_back(BECount);
-
-    if (Preds && !ENT.hasAlwaysTruePredicate())
-      Preds->add(ENT.Predicate.get());
-
-    assert((Preds || ENT.hasAlwaysTruePredicate()) &&
-           "Predicate should be always true!");
-  }
-
-  return SE->getUMinFromMismatchedTypes(Ops);
-}
-
-/// Get the exact not taken count for this loop exit.
-const SCEV *
-ScalarEvolution::BackedgeTakenInfo::getExact(BasicBlock *ExitingBlock,
-                                             ScalarEvolution *SE) const {
-  for (auto &ENT : ExitNotTaken)
-    if (ENT.ExitingBlock == ExitingBlock && ENT.hasAlwaysTruePredicate())
-      return ENT.ExactNotTaken;
-
-  return SE->getCouldNotCompute();
-}
-
-/// getMax - Get the max backedge taken count for the loop.
-const SCEV *
-ScalarEvolution::BackedgeTakenInfo::getMax(ScalarEvolution *SE) const {
-  auto PredicateNotAlwaysTrue = [](const ExitNotTakenInfo &ENT) {
-    return !ENT.hasAlwaysTruePredicate();
-  };
-
-  if (any_of(ExitNotTaken, PredicateNotAlwaysTrue) || !getMax())
-    return SE->getCouldNotCompute();
-
-  assert((isa<SCEVCouldNotCompute>(getMax()) || isa<SCEVConstant>(getMax())) &&
-         "No point in having a non-constant max backedge taken count!");
-  return getMax();
-}
-
-bool ScalarEvolution::BackedgeTakenInfo::isMaxOrZero(ScalarEvolution *SE) const {
-  auto PredicateNotAlwaysTrue = [](const ExitNotTakenInfo &ENT) {
-    return !ENT.hasAlwaysTruePredicate();
-  };
-  return MaxOrZero && !any_of(ExitNotTaken, PredicateNotAlwaysTrue);
-}
-
-bool ScalarEvolution::BackedgeTakenInfo::hasOperand(const SCEV *S,
-                                                    ScalarEvolution *SE) const {
-  if (getMax() && getMax() != SE->getCouldNotCompute() &&
-      SE->hasOperand(getMax(), S))
-    return true;
-
-  for (auto &ENT : ExitNotTaken)
-    if (ENT.ExactNotTaken != SE->getCouldNotCompute() &&
-        SE->hasOperand(ENT.ExactNotTaken, S))
-      return true;
-
-  return false;
-}
-
-ScalarEvolution::ExitLimit::ExitLimit(const SCEV *E)
-    : ExactNotTaken(E), MaxNotTaken(E) {
-  assert((isa<SCEVCouldNotCompute>(MaxNotTaken) ||
-          isa<SCEVConstant>(MaxNotTaken)) &&
-         "No point in having a non-constant max backedge taken count!");
-}
-
-ScalarEvolution::ExitLimit::ExitLimit(
-    const SCEV *E, const SCEV *M, bool MaxOrZero,
-    ArrayRef<const SmallPtrSetImpl<const SCEVPredicate *> *> PredSetList)
-    : ExactNotTaken(E), MaxNotTaken(M), MaxOrZero(MaxOrZero) {
-  assert((isa<SCEVCouldNotCompute>(ExactNotTaken) ||
-          !isa<SCEVCouldNotCompute>(MaxNotTaken)) &&
-         "Exact is not allowed to be less precise than Max");
-  assert((isa<SCEVCouldNotCompute>(MaxNotTaken) ||
-          isa<SCEVConstant>(MaxNotTaken)) &&
-         "No point in having a non-constant max backedge taken count!");
-  for (auto *PredSet : PredSetList)
-    for (auto *P : *PredSet)
-      addPredicate(P);
-}
-
-ScalarEvolution::ExitLimit::ExitLimit(
-    const SCEV *E, const SCEV *M, bool MaxOrZero,
-    const SmallPtrSetImpl<const SCEVPredicate *> &PredSet)
-    : ExitLimit(E, M, MaxOrZero, {&PredSet}) {
-  assert((isa<SCEVCouldNotCompute>(MaxNotTaken) ||
-          isa<SCEVConstant>(MaxNotTaken)) &&
-         "No point in having a non-constant max backedge taken count!");
-}
-
-ScalarEvolution::ExitLimit::ExitLimit(const SCEV *E, const SCEV *M,
-                                      bool MaxOrZero)
-    : ExitLimit(E, M, MaxOrZero, None) {
-  assert((isa<SCEVCouldNotCompute>(MaxNotTaken) ||
-          isa<SCEVConstant>(MaxNotTaken)) &&
-         "No point in having a non-constant max backedge taken count!");
-}
-
-/// Allocate memory for BackedgeTakenInfo and copy the not-taken count of each
-/// computable exit into a persistent ExitNotTakenInfo array.
-ScalarEvolution::BackedgeTakenInfo::BackedgeTakenInfo(
-    SmallVectorImpl<ScalarEvolution::BackedgeTakenInfo::EdgeExitInfo>
-        &&ExitCounts,
-    bool Complete, const SCEV *MaxCount, bool MaxOrZero)
-    : MaxAndComplete(MaxCount, Complete), MaxOrZero(MaxOrZero) {
-  using EdgeExitInfo = ScalarEvolution::BackedgeTakenInfo::EdgeExitInfo;
-
-  ExitNotTaken.reserve(ExitCounts.size());
-  std::transform(
-      ExitCounts.begin(), ExitCounts.end(), std::back_inserter(ExitNotTaken),
-      [&](const EdgeExitInfo &EEI) {
-        BasicBlock *ExitBB = EEI.first;
-        const ExitLimit &EL = EEI.second;
-        if (EL.Predicates.empty())
-          return ExitNotTakenInfo(ExitBB, EL.ExactNotTaken, nullptr);
-
-        std::unique_ptr<SCEVUnionPredicate> Predicate(new SCEVUnionPredicate);
-        for (auto *Pred : EL.Predicates)
-          Predicate->add(Pred);
-
-        return ExitNotTakenInfo(ExitBB, EL.ExactNotTaken, std::move(Predicate));
-      });
-  assert((isa<SCEVCouldNotCompute>(MaxCount) || isa<SCEVConstant>(MaxCount)) &&
-         "No point in having a non-constant max backedge taken count!");
-}
-
-/// Invalidate this result and free the ExitNotTakenInfo array.
-void ScalarEvolution::BackedgeTakenInfo::clear() {
-  ExitNotTaken.clear();
-}
-
-/// Compute the number of times the backedge of the specified loop will execute.
-ScalarEvolution::BackedgeTakenInfo
-ScalarEvolution::computeBackedgeTakenCount(const Loop *L,
-                                           bool AllowPredicates) {
-  SmallVector<BasicBlock *, 8> ExitingBlocks;
-  L->getExitingBlocks(ExitingBlocks);
-
-  using EdgeExitInfo = ScalarEvolution::BackedgeTakenInfo::EdgeExitInfo;
-
-  SmallVector<EdgeExitInfo, 4> ExitCounts;
-  bool CouldComputeBECount = true;
-  BasicBlock *Latch = L->getLoopLatch(); // may be NULL.
-  const SCEV *MustExitMaxBECount = nullptr;
-  const SCEV *MayExitMaxBECount = nullptr;
-  bool MustExitMaxOrZero = false;
-
-  // Compute the ExitLimit for each loop exit. Use this to populate ExitCounts
-  // and compute maxBECount.
-  // Do a union of all the predicates here.
-  for (unsigned i = 0, e = ExitingBlocks.size(); i != e; ++i) {
-    BasicBlock *ExitBB = ExitingBlocks[i];
-    ExitLimit EL = computeExitLimit(L, ExitBB, AllowPredicates);
-
-    assert((AllowPredicates || EL.Predicates.empty()) &&
-           "Predicated exit limit when predicates are not allowed!");
-
-    // 1. For each exit that can be computed, add an entry to ExitCounts.
-    // CouldComputeBECount is true only if all exits can be computed.
-    if (EL.ExactNotTaken == getCouldNotCompute())
-      // We couldn't compute an exact value for this exit, so
-      // we won't be able to compute an exact value for the loop.
-      CouldComputeBECount = false;
-    else
-      ExitCounts.emplace_back(ExitBB, EL);
-
-    // 2. Derive the loop's MaxBECount from each exit's max number of
-    // non-exiting iterations. Partition the loop exits into two kinds:
-    // LoopMustExits and LoopMayExits.
-    //
-    // If the exit dominates the loop latch, it is a LoopMustExit otherwise it
-    // is a LoopMayExit.  If any computable LoopMustExit is found, then
-    // MaxBECount is the minimum EL.MaxNotTaken of computable
-    // LoopMustExits. Otherwise, MaxBECount is conservatively the maximum
-    // EL.MaxNotTaken, where CouldNotCompute is considered greater than any
-    // computable EL.MaxNotTaken.
-    if (EL.MaxNotTaken != getCouldNotCompute() && Latch &&
-        DT.dominates(ExitBB, Latch)) {
-      if (!MustExitMaxBECount) {
-        MustExitMaxBECount = EL.MaxNotTaken;
-        MustExitMaxOrZero = EL.MaxOrZero;
-      } else {
-        MustExitMaxBECount =
-            getUMinFromMismatchedTypes(MustExitMaxBECount, EL.MaxNotTaken);
-      }
-    } else if (MayExitMaxBECount != getCouldNotCompute()) {
-      if (!MayExitMaxBECount || EL.MaxNotTaken == getCouldNotCompute())
-        MayExitMaxBECount = EL.MaxNotTaken;
-      else {
-        MayExitMaxBECount =
-            getUMaxFromMismatchedTypes(MayExitMaxBECount, EL.MaxNotTaken);
-      }
-    }
-  }
-  const SCEV *MaxBECount = MustExitMaxBECount ? MustExitMaxBECount :
-    (MayExitMaxBECount ? MayExitMaxBECount : getCouldNotCompute());
-  // The loop backedge will be taken the maximum or zero times if there's
-  // a single exit that must be taken the maximum or zero times.
-  bool MaxOrZero = (MustExitMaxOrZero && ExitingBlocks.size() == 1);
-  return BackedgeTakenInfo(std::move(ExitCounts), CouldComputeBECount,
-                           MaxBECount, MaxOrZero);
-}
-
-ScalarEvolution::ExitLimit
-ScalarEvolution::computeExitLimit(const Loop *L, BasicBlock *ExitingBlock,
-                                      bool AllowPredicates) {
-  assert(L->contains(ExitingBlock) && "Exit count for non-loop block?");
-  // If our exiting block does not dominate the latch, then its connection with
-  // loop's exit limit may be far from trivial.
-  const BasicBlock *Latch = L->getLoopLatch();
-  if (!Latch || !DT.dominates(ExitingBlock, Latch))
-    return getCouldNotCompute();
-
-  bool IsOnlyExit = (L->getExitingBlock() != nullptr);
-  Instruction *Term = ExitingBlock->getTerminator();
-  if (BranchInst *BI = dyn_cast<BranchInst>(Term)) {
-    assert(BI->isConditional() && "If unconditional, it can't be in loop!");
-    bool ExitIfTrue = !L->contains(BI->getSuccessor(0));
-    assert(ExitIfTrue == L->contains(BI->getSuccessor(1)) &&
-           "It should have one successor in loop and one exit block!");
-    // Proceed to the next level to examine the exit condition expression.
-    return computeExitLimitFromCond(
-        L, BI->getCondition(), ExitIfTrue,
-        /*ControlsExit=*/IsOnlyExit, AllowPredicates);
-  }
-
-  if (SwitchInst *SI = dyn_cast<SwitchInst>(Term)) {
-    // For switch, make sure that there is a single exit from the loop.
-    BasicBlock *Exit = nullptr;
-    for (auto *SBB : successors(ExitingBlock))
-      if (!L->contains(SBB)) {
-        if (Exit) // Multiple exit successors.
-          return getCouldNotCompute();
-        Exit = SBB;
-      }
-    assert(Exit && "Exiting block must have at least one exit");
-    return computeExitLimitFromSingleExitSwitch(L, SI, Exit,
-                                                /*ControlsExit=*/IsOnlyExit);
-  }
-
-  return getCouldNotCompute();
-}
-
-ScalarEvolution::ExitLimit ScalarEvolution::computeExitLimitFromCond(
-    const Loop *L, Value *ExitCond, bool ExitIfTrue,
-    bool ControlsExit, bool AllowPredicates) {
-  ScalarEvolution::ExitLimitCacheTy Cache(L, ExitIfTrue, AllowPredicates);
-  return computeExitLimitFromCondCached(Cache, L, ExitCond, ExitIfTrue,
-                                        ControlsExit, AllowPredicates);
-}
-
-Optional<ScalarEvolution::ExitLimit>
-ScalarEvolution::ExitLimitCache::find(const Loop *L, Value *ExitCond,
-                                      bool ExitIfTrue, bool ControlsExit,
-                                      bool AllowPredicates) {
-  (void)this->L;
-  (void)this->ExitIfTrue;
-  (void)this->AllowPredicates;
-
-  assert(this->L == L && this->ExitIfTrue == ExitIfTrue &&
-         this->AllowPredicates == AllowPredicates &&
-         "Variance in assumed invariant key components!");
-  auto Itr = TripCountMap.find({ExitCond, ControlsExit});
-  if (Itr == TripCountMap.end())
-    return None;
-  return Itr->second;
-}
-
-void ScalarEvolution::ExitLimitCache::insert(const Loop *L, Value *ExitCond,
-                                             bool ExitIfTrue,
-                                             bool ControlsExit,
-                                             bool AllowPredicates,
-                                             const ExitLimit &EL) {
-  assert(this->L == L && this->ExitIfTrue == ExitIfTrue &&
-         this->AllowPredicates == AllowPredicates &&
-         "Variance in assumed invariant key components!");
-
-  auto InsertResult = TripCountMap.insert({{ExitCond, ControlsExit}, EL});
-  assert(InsertResult.second && "Expected successful insertion!");
-  (void)InsertResult;
-  (void)ExitIfTrue;
-}
-
-ScalarEvolution::ExitLimit ScalarEvolution::computeExitLimitFromCondCached(
-    ExitLimitCacheTy &Cache, const Loop *L, Value *ExitCond, bool ExitIfTrue,
-    bool ControlsExit, bool AllowPredicates) {
-
-  if (auto MaybeEL =
-          Cache.find(L, ExitCond, ExitIfTrue, ControlsExit, AllowPredicates))
-    return *MaybeEL;
-
-  ExitLimit EL = computeExitLimitFromCondImpl(Cache, L, ExitCond, ExitIfTrue,
-                                              ControlsExit, AllowPredicates);
-  Cache.insert(L, ExitCond, ExitIfTrue, ControlsExit, AllowPredicates, EL);
-  return EL;
-}
-
-ScalarEvolution::ExitLimit ScalarEvolution::computeExitLimitFromCondImpl(
-    ExitLimitCacheTy &Cache, const Loop *L, Value *ExitCond, bool ExitIfTrue,
-    bool ControlsExit, bool AllowPredicates) {
-  // Check if the controlling expression for this loop is an And or Or.
-  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(ExitCond)) {
-    if (BO->getOpcode() == Instruction::And) {
-      // Recurse on the operands of the and.
-      bool EitherMayExit = !ExitIfTrue;
-      ExitLimit EL0 = computeExitLimitFromCondCached(
-          Cache, L, BO->getOperand(0), ExitIfTrue,
-          ControlsExit && !EitherMayExit, AllowPredicates);
-      ExitLimit EL1 = computeExitLimitFromCondCached(
-          Cache, L, BO->getOperand(1), ExitIfTrue,
-          ControlsExit && !EitherMayExit, AllowPredicates);
-      const SCEV *BECount = getCouldNotCompute();
-      const SCEV *MaxBECount = getCouldNotCompute();
-      if (EitherMayExit) {
-        // Both conditions must be true for the loop to continue executing.
-        // Choose the less conservative count.
-        if (EL0.ExactNotTaken == getCouldNotCompute() ||
-            EL1.ExactNotTaken == getCouldNotCompute())
-          BECount = getCouldNotCompute();
-        else
-          BECount =
-              getUMinFromMismatchedTypes(EL0.ExactNotTaken, EL1.ExactNotTaken);
-        if (EL0.MaxNotTaken == getCouldNotCompute())
-          MaxBECount = EL1.MaxNotTaken;
-        else if (EL1.MaxNotTaken == getCouldNotCompute())
-          MaxBECount = EL0.MaxNotTaken;
-        else
-          MaxBECount =
-              getUMinFromMismatchedTypes(EL0.MaxNotTaken, EL1.MaxNotTaken);
-      } else {
-        // Both conditions must be true at the same time for the loop to exit.
-        // For now, be conservative.
-        if (EL0.MaxNotTaken == EL1.MaxNotTaken)
-          MaxBECount = EL0.MaxNotTaken;
-        if (EL0.ExactNotTaken == EL1.ExactNotTaken)
-          BECount = EL0.ExactNotTaken;
-      }
-
-      // There are cases (e.g. PR26207) where computeExitLimitFromCond is able
-      // to be more aggressive when computing BECount than when computing
-      // MaxBECount.  In these cases it is possible for EL0.ExactNotTaken and
-      // EL1.ExactNotTaken to match, but for EL0.MaxNotTaken and EL1.MaxNotTaken
-      // to not.
-      if (isa<SCEVCouldNotCompute>(MaxBECount) &&
-          !isa<SCEVCouldNotCompute>(BECount))
-        MaxBECount = getConstant(getUnsignedRangeMax(BECount));
-
-      return ExitLimit(BECount, MaxBECount, false,
-                       {&EL0.Predicates, &EL1.Predicates});
-    }
-    if (BO->getOpcode() == Instruction::Or) {
-      // Recurse on the operands of the or.
-      bool EitherMayExit = ExitIfTrue;
-      ExitLimit EL0 = computeExitLimitFromCondCached(
-          Cache, L, BO->getOperand(0), ExitIfTrue,
-          ControlsExit && !EitherMayExit, AllowPredicates);
-      ExitLimit EL1 = computeExitLimitFromCondCached(
-          Cache, L, BO->getOperand(1), ExitIfTrue,
-          ControlsExit && !EitherMayExit, AllowPredicates);
-      const SCEV *BECount = getCouldNotCompute();
-      const SCEV *MaxBECount = getCouldNotCompute();
-      if (EitherMayExit) {
-        // Both conditions must be false for the loop to continue executing.
-        // Choose the less conservative count.
-        if (EL0.ExactNotTaken == getCouldNotCompute() ||
-            EL1.ExactNotTaken == getCouldNotCompute())
-          BECount = getCouldNotCompute();
-        else
-          BECount =
-              getUMinFromMismatchedTypes(EL0.ExactNotTaken, EL1.ExactNotTaken);
-        if (EL0.MaxNotTaken == getCouldNotCompute())
-          MaxBECount = EL1.MaxNotTaken;
-        else if (EL1.MaxNotTaken == getCouldNotCompute())
-          MaxBECount = EL0.MaxNotTaken;
-        else
-          MaxBECount =
-              getUMinFromMismatchedTypes(EL0.MaxNotTaken, EL1.MaxNotTaken);
-      } else {
-        // Both conditions must be false at the same time for the loop to exit.
-        // For now, be conservative.
-        if (EL0.MaxNotTaken == EL1.MaxNotTaken)
-          MaxBECount = EL0.MaxNotTaken;
-        if (EL0.ExactNotTaken == EL1.ExactNotTaken)
-          BECount = EL0.ExactNotTaken;
-      }
-
-      return ExitLimit(BECount, MaxBECount, false,
-                       {&EL0.Predicates, &EL1.Predicates});
-    }
-  }
-
-  // With an icmp, it may be feasible to compute an exact backedge-taken count.
-  // Proceed to the next level to examine the icmp.
-  if (ICmpInst *ExitCondICmp = dyn_cast<ICmpInst>(ExitCond)) {
-    ExitLimit EL =
-        computeExitLimitFromICmp(L, ExitCondICmp, ExitIfTrue, ControlsExit);
-    if (EL.hasFullInfo() || !AllowPredicates)
-      return EL;
-
-    // Try again, but use SCEV predicates this time.
-    return computeExitLimitFromICmp(L, ExitCondICmp, ExitIfTrue, ControlsExit,
-                                    /*AllowPredicates=*/true);
-  }
-
-  // Check for a constant condition. These are normally stripped out by
-  // SimplifyCFG, but ScalarEvolution may be used by a pass which wishes to
-  // preserve the CFG and is temporarily leaving constant conditions
-  // in place.
-  if (ConstantInt *CI = dyn_cast<ConstantInt>(ExitCond)) {
-    if (ExitIfTrue == !CI->getZExtValue())
-      // The backedge is always taken.
-      return getCouldNotCompute();
-    else
-      // The backedge is never taken.
-      return getZero(CI->getType());
-  }
-
-  // If it's not an integer or pointer comparison then compute it the hard way.
-  return computeExitCountExhaustively(L, ExitCond, ExitIfTrue);
-}
-
-ScalarEvolution::ExitLimit
-ScalarEvolution::computeExitLimitFromICmp(const Loop *L,
-                                          ICmpInst *ExitCond,
-                                          bool ExitIfTrue,
-                                          bool ControlsExit,
-                                          bool AllowPredicates) {
-  // If the condition was exit on true, convert the condition to exit on false
-  ICmpInst::Predicate Pred;
-  if (!ExitIfTrue)
-    Pred = ExitCond->getPredicate();
-  else
-    Pred = ExitCond->getInversePredicate();
-  const ICmpInst::Predicate OriginalPred = Pred;
-
-  // Handle common loops like: for (X = "string"; *X; ++X)
-  if (LoadInst *LI = dyn_cast<LoadInst>(ExitCond->getOperand(0)))
-    if (Constant *RHS = dyn_cast<Constant>(ExitCond->getOperand(1))) {
-      ExitLimit ItCnt =
-        computeLoadConstantCompareExitLimit(LI, RHS, L, Pred);
-      if (ItCnt.hasAnyInfo())
-        return ItCnt;
-    }
-
-  const SCEV *LHS = getSCEV(ExitCond->getOperand(0));
-  const SCEV *RHS = getSCEV(ExitCond->getOperand(1));
-
-  // Try to evaluate any dependencies out of the loop.
-  LHS = getSCEVAtScope(LHS, L);
-  RHS = getSCEVAtScope(RHS, L);
-
-  // At this point, we would like to compute how many iterations of the
-  // loop the predicate will return true for these inputs.
-  if (isLoopInvariant(LHS, L) && !isLoopInvariant(RHS, L)) {
-    // If there is a loop-invariant, force it into the RHS.
-    std::swap(LHS, RHS);
-    Pred = ICmpInst::getSwappedPredicate(Pred);
-  }
-
-  // Simplify the operands before analyzing them.
-  (void)SimplifyICmpOperands(Pred, LHS, RHS);
-
-  // If we have a comparison of a chrec against a constant, try to use value
-  // ranges to answer this query.
-  if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS))
-    if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(LHS))
-      if (AddRec->getLoop() == L) {
-        // Form the constant range.
-        ConstantRange CompRange =
-            ConstantRange::makeExactICmpRegion(Pred, RHSC->getAPInt());
-
-        const SCEV *Ret = AddRec->getNumIterationsInRange(CompRange, *this);
-        if (!isa<SCEVCouldNotCompute>(Ret)) return Ret;
-      }
-
-  switch (Pred) {
-  case ICmpInst::ICMP_NE: {                     // while (X != Y)
-    // Convert to: while (X-Y != 0)
-    ExitLimit EL = howFarToZero(getMinusSCEV(LHS, RHS), L, ControlsExit,
-                                AllowPredicates);
-    if (EL.hasAnyInfo()) return EL;
-    break;
-  }
-  case ICmpInst::ICMP_EQ: {                     // while (X == Y)
-    // Convert to: while (X-Y == 0)
-    ExitLimit EL = howFarToNonZero(getMinusSCEV(LHS, RHS), L);
-    if (EL.hasAnyInfo()) return EL;
-    break;
-  }
-  case ICmpInst::ICMP_SLT:
-  case ICmpInst::ICMP_ULT: {                    // while (X < Y)
-    bool IsSigned = Pred == ICmpInst::ICMP_SLT;
-    ExitLimit EL = howManyLessThans(LHS, RHS, L, IsSigned, ControlsExit,
-                                    AllowPredicates);
-    if (EL.hasAnyInfo()) return EL;
-    break;
-  }
-  case ICmpInst::ICMP_SGT:
-  case ICmpInst::ICMP_UGT: {                    // while (X > Y)
-    bool IsSigned = Pred == ICmpInst::ICMP_SGT;
-    ExitLimit EL =
-        howManyGreaterThans(LHS, RHS, L, IsSigned, ControlsExit,
-                            AllowPredicates);
-    if (EL.hasAnyInfo()) return EL;
-    break;
-  }
-  default:
-    break;
-  }
-
-  auto *ExhaustiveCount =
-      computeExitCountExhaustively(L, ExitCond, ExitIfTrue);
-
-  if (!isa<SCEVCouldNotCompute>(ExhaustiveCount))
-    return ExhaustiveCount;
-
-  return computeShiftCompareExitLimit(ExitCond->getOperand(0),
-                                      ExitCond->getOperand(1), L, OriginalPred);
-}
-
-ScalarEvolution::ExitLimit
-ScalarEvolution::computeExitLimitFromSingleExitSwitch(const Loop *L,
-                                                      SwitchInst *Switch,
-                                                      BasicBlock *ExitingBlock,
-                                                      bool ControlsExit) {
-  assert(!L->contains(ExitingBlock) && "Not an exiting block!");
-
-  // Give up if the exit is the default dest of a switch.
-  if (Switch->getDefaultDest() == ExitingBlock)
-    return getCouldNotCompute();
-
-  assert(L->contains(Switch->getDefaultDest()) &&
-         "Default case must not exit the loop!");
-  const SCEV *LHS = getSCEVAtScope(Switch->getCondition(), L);
-  const SCEV *RHS = getConstant(Switch->findCaseDest(ExitingBlock));
-
-  // while (X != Y) --> while (X-Y != 0)
-  ExitLimit EL = howFarToZero(getMinusSCEV(LHS, RHS), L, ControlsExit);
-  if (EL.hasAnyInfo())
-    return EL;
-
-  return getCouldNotCompute();
-}
-
-static ConstantInt *
-EvaluateConstantChrecAtConstant(const SCEVAddRecExpr *AddRec, ConstantInt *C,
-                                ScalarEvolution &SE) {
-  const SCEV *InVal = SE.getConstant(C);
-  const SCEV *Val = AddRec->evaluateAtIteration(InVal, SE);
-  assert(isa<SCEVConstant>(Val) &&
-         "Evaluation of SCEV at constant didn't fold correctly?");
-  return cast<SCEVConstant>(Val)->getValue();
-}
-
-/// Given an exit condition of 'icmp op load X, cst', try to see if we can
-/// compute the backedge execution count.
-ScalarEvolution::ExitLimit
-ScalarEvolution::computeLoadConstantCompareExitLimit(
-  LoadInst *LI,
-  Constant *RHS,
-  const Loop *L,
-  ICmpInst::Predicate predicate) {
-  if (LI->isVolatile()) return getCouldNotCompute();
-
-  // Check to see if the loaded pointer is a getelementptr of a global.
-  // TODO: Use SCEV instead of manually grubbing with GEPs.
-  GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(LI->getOperand(0));
-  if (!GEP) return getCouldNotCompute();
-
-  // Make sure that it is really a constant global we are gepping, with an
-  // initializer, and make sure the first IDX is really 0.
-  GlobalVariable *GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
-  if (!GV || !GV->isConstant() || !GV->hasDefinitiveInitializer() ||
-      GEP->getNumOperands() < 3 || !isa<Constant>(GEP->getOperand(1)) ||
-      !cast<Constant>(GEP->getOperand(1))->isNullValue())
-    return getCouldNotCompute();
-
-  // Okay, we allow one non-constant index into the GEP instruction.
-  Value *VarIdx = nullptr;
-  std::vector<Constant*> Indexes;
-  unsigned VarIdxNum = 0;
-  for (unsigned i = 2, e = GEP->getNumOperands(); i != e; ++i)
-    if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(i))) {
-      Indexes.push_back(CI);
-    } else if (!isa<ConstantInt>(GEP->getOperand(i))) {
-      if (VarIdx) return getCouldNotCompute();  // Multiple non-constant idx's.
-      VarIdx = GEP->getOperand(i);
-      VarIdxNum = i-2;
-      Indexes.push_back(nullptr);
-    }
-
-  // Loop-invariant loads may be a byproduct of loop optimization. Skip them.
-  if (!VarIdx)
-    return getCouldNotCompute();
-
-  // Okay, we know we have a (load (gep GV, 0, X)) comparison with a constant.
-  // Check to see if X is a loop variant variable value now.
-  const SCEV *Idx = getSCEV(VarIdx);
-  Idx = getSCEVAtScope(Idx, L);
-
-  // We can only recognize very limited forms of loop index expressions, in
-  // particular, only affine AddRec's like {C1,+,C2}.
-  const SCEVAddRecExpr *IdxExpr = dyn_cast<SCEVAddRecExpr>(Idx);
-  if (!IdxExpr || !IdxExpr->isAffine() || isLoopInvariant(IdxExpr, L) ||
-      !isa<SCEVConstant>(IdxExpr->getOperand(0)) ||
-      !isa<SCEVConstant>(IdxExpr->getOperand(1)))
-    return getCouldNotCompute();
-
-  unsigned MaxSteps = MaxBruteForceIterations;
-  for (unsigned IterationNum = 0; IterationNum != MaxSteps; ++IterationNum) {
-    ConstantInt *ItCst = ConstantInt::get(
-                           cast<IntegerType>(IdxExpr->getType()), IterationNum);
-    ConstantInt *Val = EvaluateConstantChrecAtConstant(IdxExpr, ItCst, *this);
-
-    // Form the GEP offset.
-    Indexes[VarIdxNum] = Val;
-
-    Constant *Result = ConstantFoldLoadThroughGEPIndices(GV->getInitializer(),
-                                                         Indexes);
-    if (!Result) break;  // Cannot compute!
-
-    // Evaluate the condition for this iteration.
-    Result = ConstantExpr::getICmp(predicate, Result, RHS);
-    if (!isa<ConstantInt>(Result)) break;  // Couldn't decide for sure
-    if (cast<ConstantInt>(Result)->getValue().isMinValue()) {
-      ++NumArrayLenItCounts;
-      return getConstant(ItCst);   // Found terminating iteration!
-    }
-  }
-  return getCouldNotCompute();
-}
-
-ScalarEvolution::ExitLimit ScalarEvolution::computeShiftCompareExitLimit(
-    Value *LHS, Value *RHSV, const Loop *L, ICmpInst::Predicate Pred) {
-  ConstantInt *RHS = dyn_cast<ConstantInt>(RHSV);
-  if (!RHS)
-    return getCouldNotCompute();
-
-  const BasicBlock *Latch = L->getLoopLatch();
-  if (!Latch)
-    return getCouldNotCompute();
-
-  const BasicBlock *Predecessor = L->getLoopPredecessor();
-  if (!Predecessor)
-    return getCouldNotCompute();
-
-  // Return true if V is of the form "LHS `shift_op` <positive constant>".
-  // Return LHS in OutLHS and shift_opt in OutOpCode.
-  auto MatchPositiveShift =
-      [](Value *V, Value *&OutLHS, Instruction::BinaryOps &OutOpCode) {
-
-    using namespace PatternMatch;
-
-    ConstantInt *ShiftAmt;
-    if (match(V, m_LShr(m_Value(OutLHS), m_ConstantInt(ShiftAmt))))
-      OutOpCode = Instruction::LShr;
-    else if (match(V, m_AShr(m_Value(OutLHS), m_ConstantInt(ShiftAmt))))
-      OutOpCode = Instruction::AShr;
-    else if (match(V, m_Shl(m_Value(OutLHS), m_ConstantInt(ShiftAmt))))
-      OutOpCode = Instruction::Shl;
-    else
-      return false;
-
-    return ShiftAmt->getValue().isStrictlyPositive();
-  };
-
-  // Recognize a "shift recurrence" either of the form %iv or of %iv.shifted in
-  //
-  // loop:
-  //   %iv = phi i32 [ %iv.shifted, %loop ], [ %val, %preheader ]
-  //   %iv.shifted = lshr i32 %iv, <positive constant>
-  //
-  // Return true on a successful match.  Return the corresponding PHI node (%iv
-  // above) in PNOut and the opcode of the shift operation in OpCodeOut.
-  auto MatchShiftRecurrence =
-      [&](Value *V, PHINode *&PNOut, Instruction::BinaryOps &OpCodeOut) {
-    Optional<Instruction::BinaryOps> PostShiftOpCode;
-
-    {
-      Instruction::BinaryOps OpC;
-      Value *V;
-
-      // If we encounter a shift instruction, "peel off" the shift operation,
-      // and remember that we did so.  Later when we inspect %iv's backedge
-      // value, we will make sure that the backedge value uses the same
-      // operation.
-      //
-      // Note: the peeled shift operation does not have to be the same
-      // instruction as the one feeding into the PHI's backedge value.  We only
-      // really care about it being the same *kind* of shift instruction --
-      // that's all that is required for our later inferences to hold.
-      if (MatchPositiveShift(LHS, V, OpC)) {
-        PostShiftOpCode = OpC;
-        LHS = V;
-      }
-    }
-
-    PNOut = dyn_cast<PHINode>(LHS);
-    if (!PNOut || PNOut->getParent() != L->getHeader())
-      return false;
-
-    Value *BEValue = PNOut->getIncomingValueForBlock(Latch);
-    Value *OpLHS;
-
-    return
-        // The backedge value for the PHI node must be a shift by a positive
-        // amount
-        MatchPositiveShift(BEValue, OpLHS, OpCodeOut) &&
-
-        // of the PHI node itself
-        OpLHS == PNOut &&
-
-        // and the kind of shift should be match the kind of shift we peeled
-        // off, if any.
-        (!PostShiftOpCode.hasValue() || *PostShiftOpCode == OpCodeOut);
-  };
-
-  PHINode *PN;
-  Instruction::BinaryOps OpCode;
-  if (!MatchShiftRecurrence(LHS, PN, OpCode))
-    return getCouldNotCompute();
-
-  const DataLayout &DL = getDataLayout();
-
-  // The key rationale for this optimization is that for some kinds of shift
-  // recurrences, the value of the recurrence "stabilizes" to either 0 or -1
-  // within a finite number of iterations.  If the condition guarding the
-  // backedge (in the sense that the backedge is taken if the condition is true)
-  // is false for the value the shift recurrence stabilizes to, then we know
-  // that the backedge is taken only a finite number of times.
-
-  ConstantInt *StableValue = nullptr;
-  switch (OpCode) {
-  default:
-    llvm_unreachable("Impossible case!");
-
-  case Instruction::AShr: {
-    // {K,ashr,<positive-constant>} stabilizes to signum(K) in at most
-    // bitwidth(K) iterations.
-    Value *FirstValue = PN->getIncomingValueForBlock(Predecessor);
-    KnownBits Known = computeKnownBits(FirstValue, DL, 0, nullptr,
-                                       Predecessor->getTerminator(), &DT);
-    auto *Ty = cast<IntegerType>(RHS->getType());
-    if (Known.isNonNegative())
-      StableValue = ConstantInt::get(Ty, 0);
-    else if (Known.isNegative())
-      StableValue = ConstantInt::get(Ty, -1, true);
-    else
-      return getCouldNotCompute();
-
-    break;
-  }
-  case Instruction::LShr:
-  case Instruction::Shl:
-    // Both {K,lshr,<positive-constant>} and {K,shl,<positive-constant>}
-    // stabilize to 0 in at most bitwidth(K) iterations.
-    StableValue = ConstantInt::get(cast<IntegerType>(RHS->getType()), 0);
-    break;
-  }
-
-  auto *Result =
-      ConstantFoldCompareInstOperands(Pred, StableValue, RHS, DL, &TLI);
-  assert(Result->getType()->isIntegerTy(1) &&
-         "Otherwise cannot be an operand to a branch instruction");
-
-  if (Result->isZeroValue()) {
-    unsigned BitWidth = getTypeSizeInBits(RHS->getType());
-    const SCEV *UpperBound =
-        getConstant(getEffectiveSCEVType(RHS->getType()), BitWidth);
-    return ExitLimit(getCouldNotCompute(), UpperBound, false);
-  }
-
-  return getCouldNotCompute();
-}
-
-/// Return true if we can constant fold an instruction of the specified type,
-/// assuming that all operands were constants.
-static bool CanConstantFold(const Instruction *I) {
-  if (isa<BinaryOperator>(I) || isa<CmpInst>(I) ||
-      isa<SelectInst>(I) || isa<CastInst>(I) || isa<GetElementPtrInst>(I) ||
-      isa<LoadInst>(I))
-    return true;
-
-  if (const CallInst *CI = dyn_cast<CallInst>(I))
-    if (const Function *F = CI->getCalledFunction())
-      return canConstantFoldCallTo(CI, F);
-  return false;
-}
-
-/// Determine whether this instruction can constant evolve within this loop
-/// assuming its operands can all constant evolve.
-static bool canConstantEvolve(Instruction *I, const Loop *L) {
-  // An instruction outside of the loop can't be derived from a loop PHI.
-  if (!L->contains(I)) return false;
-
-  if (isa<PHINode>(I)) {
-    // We don't currently keep track of the control flow needed to evaluate
-    // PHIs, so we cannot handle PHIs inside of loops.
-    return L->getHeader() == I->getParent();
-  }
-
-  // If we won't be able to constant fold this expression even if the operands
-  // are constants, bail early.
-  return CanConstantFold(I);
-}
-
-/// getConstantEvolvingPHIOperands - Implement getConstantEvolvingPHI by
-/// recursing through each instruction operand until reaching a loop header phi.
-static PHINode *
-getConstantEvolvingPHIOperands(Instruction *UseInst, const Loop *L,
-                               DenseMap<Instruction *, PHINode *> &PHIMap,
-                               unsigned Depth) {
-  if (Depth > MaxConstantEvolvingDepth)
-    return nullptr;
-
-  // Otherwise, we can evaluate this instruction if all of its operands are
-  // constant or derived from a PHI node themselves.
-  PHINode *PHI = nullptr;
-  for (Value *Op : UseInst->operands()) {
-    if (isa<Constant>(Op)) continue;
-
-    Instruction *OpInst = dyn_cast<Instruction>(Op);
-    if (!OpInst || !canConstantEvolve(OpInst, L)) return nullptr;
-
-    PHINode *P = dyn_cast<PHINode>(OpInst);
-    if (!P)
-      // If this operand is already visited, reuse the prior result.
-      // We may have P != PHI if this is the deepest point at which the
-      // inconsistent paths meet.
-      P = PHIMap.lookup(OpInst);
-    if (!P) {
-      // Recurse and memoize the results, whether a phi is found or not.
-      // This recursive call invalidates pointers into PHIMap.
-      P = getConstantEvolvingPHIOperands(OpInst, L, PHIMap, Depth + 1);
-      PHIMap[OpInst] = P;
-    }
-    if (!P)
-      return nullptr;  // Not evolving from PHI
-    if (PHI && PHI != P)
-      return nullptr;  // Evolving from multiple different PHIs.
-    PHI = P;
-  }
-  // This is a expression evolving from a constant PHI!
-  return PHI;
-}
-
-/// getConstantEvolvingPHI - Given an LLVM value and a loop, return a PHI node
-/// in the loop that V is derived from.  We allow arbitrary operations along the
-/// way, but the operands of an operation must either be constants or a value
-/// derived from a constant PHI.  If this expression does not fit with these
-/// constraints, return null.
-static PHINode *getConstantEvolvingPHI(Value *V, const Loop *L) {
-  Instruction *I = dyn_cast<Instruction>(V);
-  if (!I || !canConstantEvolve(I, L)) return nullptr;
-
-  if (PHINode *PN = dyn_cast<PHINode>(I))
-    return PN;
-
-  // Record non-constant instructions contained by the loop.
-  DenseMap<Instruction *, PHINode *> PHIMap;
-  return getConstantEvolvingPHIOperands(I, L, PHIMap, 0);
-}
-
-/// EvaluateExpression - Given an expression that passes the
-/// getConstantEvolvingPHI predicate, evaluate its value assuming the PHI node
-/// in the loop has the value PHIVal.  If we can't fold this expression for some
-/// reason, return null.
-static Constant *EvaluateExpression(Value *V, const Loop *L,
-                                    DenseMap<Instruction *, Constant *> &Vals,
-                                    const DataLayout &DL,
-                                    const TargetLibraryInfo *TLI) {
-  // Convenient constant check, but redundant for recursive calls.
-  if (Constant *C = dyn_cast<Constant>(V)) return C;
-  Instruction *I = dyn_cast<Instruction>(V);
-  if (!I) return nullptr;
-
-  if (Constant *C = Vals.lookup(I)) return C;
-
-  // An instruction inside the loop depends on a value outside the loop that we
-  // weren't given a mapping for, or a value such as a call inside the loop.
-  if (!canConstantEvolve(I, L)) return nullptr;
-
-  // An unmapped PHI can be due to a branch or another loop inside this loop,
-  // or due to this not being the initial iteration through a loop where we
-  // couldn't compute the evolution of this particular PHI last time.
-  if (isa<PHINode>(I)) return nullptr;
-
-  std::vector<Constant*> Operands(I->getNumOperands());
-
-  for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
-    Instruction *Operand = dyn_cast<Instruction>(I->getOperand(i));
-    if (!Operand) {
-      Operands[i] = dyn_cast<Constant>(I->getOperand(i));
-      if (!Operands[i]) return nullptr;
-      continue;
-    }
-    Constant *C = EvaluateExpression(Operand, L, Vals, DL, TLI);
-    Vals[Operand] = C;
-    if (!C) return nullptr;
-    Operands[i] = C;
-  }
-
-  if (CmpInst *CI = dyn_cast<CmpInst>(I))
-    return ConstantFoldCompareInstOperands(CI->getPredicate(), Operands[0],
-                                           Operands[1], DL, TLI);
-  if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
-    if (!LI->isVolatile())
-      return ConstantFoldLoadFromConstPtr(Operands[0], LI->getType(), DL);
-  }
-  return ConstantFoldInstOperands(I, Operands, DL, TLI);
-}
-
-
-// If every incoming value to PN except the one for BB is a specific Constant,
-// return that, else return nullptr.
-static Constant *getOtherIncomingValue(PHINode *PN, BasicBlock *BB) {
-  Constant *IncomingVal = nullptr;
-
-  for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
-    if (PN->getIncomingBlock(i) == BB)
-      continue;
-
-    auto *CurrentVal = dyn_cast<Constant>(PN->getIncomingValue(i));
-    if (!CurrentVal)
-      return nullptr;
-
-    if (IncomingVal != CurrentVal) {
-      if (IncomingVal)
-        return nullptr;
-      IncomingVal = CurrentVal;
-    }
-  }
-
-  return IncomingVal;
-}
-
-/// getConstantEvolutionLoopExitValue - If we know that the specified Phi is
-/// in the header of its containing loop, we know the loop executes a
-/// constant number of times, and the PHI node is just a recurrence
-/// involving constants, fold it.
-Constant *
-ScalarEvolution::getConstantEvolutionLoopExitValue(PHINode *PN,
-                                                   const APInt &BEs,
-                                                   const Loop *L) {
-  auto I = ConstantEvolutionLoopExitValue.find(PN);
-  if (I != ConstantEvolutionLoopExitValue.end())
-    return I->second;
-
-  if (BEs.ugt(MaxBruteForceIterations))
-    return ConstantEvolutionLoopExitValue[PN] = nullptr;  // Not going to evaluate it.
-
-  Constant *&RetVal = ConstantEvolutionLoopExitValue[PN];
-
-  DenseMap<Instruction *, Constant *> CurrentIterVals;
-  BasicBlock *Header = L->getHeader();
-  assert(PN->getParent() == Header && "Can't evaluate PHI not in loop header!");
-
-  BasicBlock *Latch = L->getLoopLatch();
-  if (!Latch)
-    return nullptr;
-
-  for (PHINode &PHI : Header->phis()) {
-    if (auto *StartCST = getOtherIncomingValue(&PHI, Latch))
-      CurrentIterVals[&PHI] = StartCST;
-  }
-  if (!CurrentIterVals.count(PN))
-    return RetVal = nullptr;
-
-  Value *BEValue = PN->getIncomingValueForBlock(Latch);
-
-  // Execute the loop symbolically to determine the exit value.
-  assert(BEs.getActiveBits() < CHAR_BIT * sizeof(unsigned) &&
-         "BEs is <= MaxBruteForceIterations which is an 'unsigned'!");
-
-  unsigned NumIterations = BEs.getZExtValue(); // must be in range
-  unsigned IterationNum = 0;
-  const DataLayout &DL = getDataLayout();
-  for (; ; ++IterationNum) {
-    if (IterationNum == NumIterations)
-      return RetVal = CurrentIterVals[PN];  // Got exit value!
-
-    // Compute the value of the PHIs for the next iteration.
-    // EvaluateExpression adds non-phi values to the CurrentIterVals map.
-    DenseMap<Instruction *, Constant *> NextIterVals;
-    Constant *NextPHI =
-        EvaluateExpression(BEValue, L, CurrentIterVals, DL, &TLI);
-    if (!NextPHI)
-      return nullptr;        // Couldn't evaluate!
-    NextIterVals[PN] = NextPHI;
-
-    bool StoppedEvolving = NextPHI == CurrentIterVals[PN];
-
-    // Also evaluate the other PHI nodes.  However, we don't get to stop if we
-    // cease to be able to evaluate one of them or if they stop evolving,
-    // because that doesn't necessarily prevent us from computing PN.
-    SmallVector<std::pair<PHINode *, Constant *>, 8> PHIsToCompute;
-    for (const auto &I : CurrentIterVals) {
-      PHINode *PHI = dyn_cast<PHINode>(I.first);
-      if (!PHI || PHI == PN || PHI->getParent() != Header) continue;
-      PHIsToCompute.emplace_back(PHI, I.second);
-    }
-    // We use two distinct loops because EvaluateExpression may invalidate any
-    // iterators into CurrentIterVals.
-    for (const auto &I : PHIsToCompute) {
-      PHINode *PHI = I.first;
-      Constant *&NextPHI = NextIterVals[PHI];
-      if (!NextPHI) {   // Not already computed.
-        Value *BEValue = PHI->getIncomingValueForBlock(Latch);
-        NextPHI = EvaluateExpression(BEValue, L, CurrentIterVals, DL, &TLI);
-      }
-      if (NextPHI != I.second)
-        StoppedEvolving = false;
-    }
-
-    // If all entries in CurrentIterVals == NextIterVals then we can stop
-    // iterating, the loop can't continue to change.
-    if (StoppedEvolving)
-      return RetVal = CurrentIterVals[PN];
-
-    CurrentIterVals.swap(NextIterVals);
-  }
-}
-
-const SCEV *ScalarEvolution::computeExitCountExhaustively(const Loop *L,
-                                                          Value *Cond,
-                                                          bool ExitWhen) {
-  PHINode *PN = getConstantEvolvingPHI(Cond, L);
-  if (!PN) return getCouldNotCompute();
-
-  // If the loop is canonicalized, the PHI will have exactly two entries.
-  // That's the only form we support here.
-  if (PN->getNumIncomingValues() != 2) return getCouldNotCompute();
-
-  DenseMap<Instruction *, Constant *> CurrentIterVals;
-  BasicBlock *Header = L->getHeader();
-  assert(PN->getParent() == Header && "Can't evaluate PHI not in loop header!");
-
-  BasicBlock *Latch = L->getLoopLatch();
-  assert(Latch && "Should follow from NumIncomingValues == 2!");
-
-  for (PHINode &PHI : Header->phis()) {
-    if (auto *StartCST = getOtherIncomingValue(&PHI, Latch))
-      CurrentIterVals[&PHI] = StartCST;
-  }
-  if (!CurrentIterVals.count(PN))
-    return getCouldNotCompute();
-
-  // Okay, we find a PHI node that defines the trip count of this loop.  Execute
-  // the loop symbolically to determine when the condition gets a value of
-  // "ExitWhen".
-  unsigned MaxIterations = MaxBruteForceIterations;   // Limit analysis.
-  const DataLayout &DL = getDataLayout();
-  for (unsigned IterationNum = 0; IterationNum != MaxIterations;++IterationNum){
-    auto *CondVal = dyn_cast_or_null<ConstantInt>(
-        EvaluateExpression(Cond, L, CurrentIterVals, DL, &TLI));
-
-    // Couldn't symbolically evaluate.
-    if (!CondVal) return getCouldNotCompute();
-
-    if (CondVal->getValue() == uint64_t(ExitWhen)) {
-      ++NumBruteForceTripCountsComputed;
-      return getConstant(Type::getInt32Ty(getContext()), IterationNum);
-    }
-
-    // Update all the PHI nodes for the next iteration.
-    DenseMap<Instruction *, Constant *> NextIterVals;
-
-    // Create a list of which PHIs we need to compute. We want to do this before
-    // calling EvaluateExpression on them because that may invalidate iterators
-    // into CurrentIterVals.
-    SmallVector<PHINode *, 8> PHIsToCompute;
-    for (const auto &I : CurrentIterVals) {
-      PHINode *PHI = dyn_cast<PHINode>(I.first);
-      if (!PHI || PHI->getParent() != Header) continue;
-      PHIsToCompute.push_back(PHI);
-    }
-    for (PHINode *PHI : PHIsToCompute) {
-      Constant *&NextPHI = NextIterVals[PHI];
-      if (NextPHI) continue;    // Already computed!
-
-      Value *BEValue = PHI->getIncomingValueForBlock(Latch);
-      NextPHI = EvaluateExpression(BEValue, L, CurrentIterVals, DL, &TLI);
-    }
-    CurrentIterVals.swap(NextIterVals);
-  }
-
-  // Too many iterations were needed to evaluate.
-  return getCouldNotCompute();
-}
-
-const SCEV *ScalarEvolution::getSCEVAtScope(const SCEV *V, const Loop *L) {
-  SmallVector<std::pair<const Loop *, const SCEV *>, 2> &Values =
-      ValuesAtScopes[V];
-  // Check to see if we've folded this expression at this loop before.
-  for (auto &LS : Values)
-    if (LS.first == L)
-      return LS.second ? LS.second : V;
-
-  Values.emplace_back(L, nullptr);
-
-  // Otherwise compute it.
-  const SCEV *C = computeSCEVAtScope(V, L);
-  for (auto &LS : reverse(ValuesAtScopes[V]))
-    if (LS.first == L) {
-      LS.second = C;
-      break;
-    }
-  return C;
-}
-
-/// This builds up a Constant using the ConstantExpr interface.  That way, we
-/// will return Constants for objects which aren't represented by a
-/// SCEVConstant, because SCEVConstant is restricted to ConstantInt.
-/// Returns NULL if the SCEV isn't representable as a Constant.
-static Constant *BuildConstantFromSCEV(const SCEV *V) {
-  switch (static_cast<SCEVTypes>(V->getSCEVType())) {
-    case scCouldNotCompute:
-    case scAddRecExpr:
-      break;
-    case scConstant:
-      return cast<SCEVConstant>(V)->getValue();
-    case scUnknown:
-      return dyn_cast<Constant>(cast<SCEVUnknown>(V)->getValue());
-    case scSignExtend: {
-      const SCEVSignExtendExpr *SS = cast<SCEVSignExtendExpr>(V);
-      if (Constant *CastOp = BuildConstantFromSCEV(SS->getOperand()))
-        return ConstantExpr::getSExt(CastOp, SS->getType());
-      break;
-    }
-    case scZeroExtend: {
-      const SCEVZeroExtendExpr *SZ = cast<SCEVZeroExtendExpr>(V);
-      if (Constant *CastOp = BuildConstantFromSCEV(SZ->getOperand()))
-        return ConstantExpr::getZExt(CastOp, SZ->getType());
-      break;
-    }
-    case scTruncate: {
-      const SCEVTruncateExpr *ST = cast<SCEVTruncateExpr>(V);
-      if (Constant *CastOp = BuildConstantFromSCEV(ST->getOperand()))
-        return ConstantExpr::getTrunc(CastOp, ST->getType());
-      break;
-    }
-    case scAddExpr: {
-      const SCEVAddExpr *SA = cast<SCEVAddExpr>(V);
-      if (Constant *C = BuildConstantFromSCEV(SA->getOperand(0))) {
-        if (PointerType *PTy = dyn_cast<PointerType>(C->getType())) {
-          unsigned AS = PTy->getAddressSpace();
-          Type *DestPtrTy = Type::getInt8PtrTy(C->getContext(), AS);
-          C = ConstantExpr::getBitCast(C, DestPtrTy);
-        }
-        for (unsigned i = 1, e = SA->getNumOperands(); i != e; ++i) {
-          Constant *C2 = BuildConstantFromSCEV(SA->getOperand(i));
-          if (!C2) return nullptr;
-
-          // First pointer!
-          if (!C->getType()->isPointerTy() && C2->getType()->isPointerTy()) {
-            unsigned AS = C2->getType()->getPointerAddressSpace();
-            std::swap(C, C2);
-            Type *DestPtrTy = Type::getInt8PtrTy(C->getContext(), AS);
-            // The offsets have been converted to bytes.  We can add bytes to an
-            // i8* by GEP with the byte count in the first index.
-            C = ConstantExpr::getBitCast(C, DestPtrTy);
-          }
-
-          // Don't bother trying to sum two pointers. We probably can't
-          // statically compute a load that results from it anyway.
-          if (C2->getType()->isPointerTy())
-            return nullptr;
-
-          if (PointerType *PTy = dyn_cast<PointerType>(C->getType())) {
-            if (PTy->getElementType()->isStructTy())
-              C2 = ConstantExpr::getIntegerCast(
-                  C2, Type::getInt32Ty(C->getContext()), true);
-            C = ConstantExpr::getGetElementPtr(PTy->getElementType(), C, C2);
-          } else
-            C = ConstantExpr::getAdd(C, C2);
-        }
-        return C;
-      }
-      break;
-    }
-    case scMulExpr: {
-      const SCEVMulExpr *SM = cast<SCEVMulExpr>(V);
-      if (Constant *C = BuildConstantFromSCEV(SM->getOperand(0))) {
-        // Don't bother with pointers at all.
-        if (C->getType()->isPointerTy()) return nullptr;
-        for (unsigned i = 1, e = SM->getNumOperands(); i != e; ++i) {
-          Constant *C2 = BuildConstantFromSCEV(SM->getOperand(i));
-          if (!C2 || C2->getType()->isPointerTy()) return nullptr;
-          C = ConstantExpr::getMul(C, C2);
-        }
-        return C;
-      }
-      break;
-    }
-    case scUDivExpr: {
-      const SCEVUDivExpr *SU = cast<SCEVUDivExpr>(V);
-      if (Constant *LHS = BuildConstantFromSCEV(SU->getLHS()))
-        if (Constant *RHS = BuildConstantFromSCEV(SU->getRHS()))
-          if (LHS->getType() == RHS->getType())
-            return ConstantExpr::getUDiv(LHS, RHS);
-      break;
-    }
-    case scSMaxExpr:
-    case scUMaxExpr:
-      break; // TODO: smax, umax.
-  }
-  return nullptr;
-}
-
-const SCEV *ScalarEvolution::computeSCEVAtScope(const SCEV *V, const Loop *L) {
-  if (isa<SCEVConstant>(V)) return V;
-
-  // If this instruction is evolved from a constant-evolving PHI, compute the
-  // exit value from the loop without using SCEVs.
-  if (const SCEVUnknown *SU = dyn_cast<SCEVUnknown>(V)) {
-    if (Instruction *I = dyn_cast<Instruction>(SU->getValue())) {
-      const Loop *LI = this->LI[I->getParent()];
-      if (LI && LI->getParentLoop() == L)  // Looking for loop exit value.
-        if (PHINode *PN = dyn_cast<PHINode>(I))
-          if (PN->getParent() == LI->getHeader()) {
-            // Okay, there is no closed form solution for the PHI node.  Check
-            // to see if the loop that contains it has a known backedge-taken
-            // count.  If so, we may be able to force computation of the exit
-            // value.
-            const SCEV *BackedgeTakenCount = getBackedgeTakenCount(LI);
-            if (const SCEVConstant *BTCC =
-                  dyn_cast<SCEVConstant>(BackedgeTakenCount)) {
-
-              // This trivial case can show up in some degenerate cases where
-              // the incoming IR has not yet been fully simplified.
-              if (BTCC->getValue()->isZero()) {
-                Value *InitValue = nullptr;
-                bool MultipleInitValues = false;
-                for (unsigned i = 0; i < PN->getNumIncomingValues(); i++) {
-                  if (!LI->contains(PN->getIncomingBlock(i))) {
-                    if (!InitValue)
-                      InitValue = PN->getIncomingValue(i);
-                    else if (InitValue != PN->getIncomingValue(i)) {
-                      MultipleInitValues = true;
-                      break;
-                    }
-                  }
-                  if (!MultipleInitValues && InitValue)
-                    return getSCEV(InitValue);
-                }
-              }
-              // Okay, we know how many times the containing loop executes.  If
-              // this is a constant evolving PHI node, get the final value at
-              // the specified iteration number.
-              Constant *RV =
-                  getConstantEvolutionLoopExitValue(PN, BTCC->getAPInt(), LI);
-              if (RV) return getSCEV(RV);
-            }
-          }
-
-      // Okay, this is an expression that we cannot symbolically evaluate
-      // into a SCEV.  Check to see if it's possible to symbolically evaluate
-      // the arguments into constants, and if so, try to constant propagate the
-      // result.  This is particularly useful for computing loop exit values.
-      if (CanConstantFold(I)) {
-        SmallVector<Constant *, 4> Operands;
-        bool MadeImprovement = false;
-        for (Value *Op : I->operands()) {
-          if (Constant *C = dyn_cast<Constant>(Op)) {
-            Operands.push_back(C);
-            continue;
-          }
-
-          // If any of the operands is non-constant and if they are
-          // non-integer and non-pointer, don't even try to analyze them
-          // with scev techniques.
-          if (!isSCEVable(Op->getType()))
-            return V;
-
-          const SCEV *OrigV = getSCEV(Op);
-          const SCEV *OpV = getSCEVAtScope(OrigV, L);
-          MadeImprovement |= OrigV != OpV;
-
-          Constant *C = BuildConstantFromSCEV(OpV);
-          if (!C) return V;
-          if (C->getType() != Op->getType())
-            C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
-                                                              Op->getType(),
-                                                              false),
-                                      C, Op->getType());
-          Operands.push_back(C);
-        }
-
-        // Check to see if getSCEVAtScope actually made an improvement.
-        if (MadeImprovement) {
-          Constant *C = nullptr;
-          const DataLayout &DL = getDataLayout();
-          if (const CmpInst *CI = dyn_cast<CmpInst>(I))
-            C = ConstantFoldCompareInstOperands(CI->getPredicate(), Operands[0],
-                                                Operands[1], DL, &TLI);
-          else if (const LoadInst *LI = dyn_cast<LoadInst>(I)) {
-            if (!LI->isVolatile())
-              C = ConstantFoldLoadFromConstPtr(Operands[0], LI->getType(), DL);
-          } else
-            C = ConstantFoldInstOperands(I, Operands, DL, &TLI);
-          if (!C) return V;
-          return getSCEV(C);
-        }
-      }
-    }
-
-    // This is some other type of SCEVUnknown, just return it.
-    return V;
-  }
-
-  if (const SCEVCommutativeExpr *Comm = dyn_cast<SCEVCommutativeExpr>(V)) {
-    // Avoid performing the look-up in the common case where the specified
-    // expression has no loop-variant portions.
-    for (unsigned i = 0, e = Comm->getNumOperands(); i != e; ++i) {
-      const SCEV *OpAtScope = getSCEVAtScope(Comm->getOperand(i), L);
-      if (OpAtScope != Comm->getOperand(i)) {
-        // Okay, at least one of these operands is loop variant but might be
-        // foldable.  Build a new instance of the folded commutative expression.
-        SmallVector<const SCEV *, 8> NewOps(Comm->op_begin(),
-                                            Comm->op_begin()+i);
-        NewOps.push_back(OpAtScope);
-
-        for (++i; i != e; ++i) {
-          OpAtScope = getSCEVAtScope(Comm->getOperand(i), L);
-          NewOps.push_back(OpAtScope);
-        }
-        if (isa<SCEVAddExpr>(Comm))
-          return getAddExpr(NewOps);
-        if (isa<SCEVMulExpr>(Comm))
-          return getMulExpr(NewOps);
-        if (isa<SCEVSMaxExpr>(Comm))
-          return getSMaxExpr(NewOps);
-        if (isa<SCEVUMaxExpr>(Comm))
-          return getUMaxExpr(NewOps);
-        llvm_unreachable("Unknown commutative SCEV type!");
-      }
-    }
-    // If we got here, all operands are loop invariant.
-    return Comm;
-  }
-
-  if (const SCEVUDivExpr *Div = dyn_cast<SCEVUDivExpr>(V)) {
-    const SCEV *LHS = getSCEVAtScope(Div->getLHS(), L);
-    const SCEV *RHS = getSCEVAtScope(Div->getRHS(), L);
-    if (LHS == Div->getLHS() && RHS == Div->getRHS())
-      return Div;   // must be loop invariant
-    return getUDivExpr(LHS, RHS);
-  }
-
-  // If this is a loop recurrence for a loop that does not contain L, then we
-  // are dealing with the final value computed by the loop.
-  if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(V)) {
-    // First, attempt to evaluate each operand.
-    // Avoid performing the look-up in the common case where the specified
-    // expression has no loop-variant portions.
-    for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i) {
-      const SCEV *OpAtScope = getSCEVAtScope(AddRec->getOperand(i), L);
-      if (OpAtScope == AddRec->getOperand(i))
-        continue;
-
-      // Okay, at least one of these operands is loop variant but might be
-      // foldable.  Build a new instance of the folded commutative expression.
-      SmallVector<const SCEV *, 8> NewOps(AddRec->op_begin(),
-                                          AddRec->op_begin()+i);
-      NewOps.push_back(OpAtScope);
-      for (++i; i != e; ++i)
-        NewOps.push_back(getSCEVAtScope(AddRec->getOperand(i), L));
-
-      const SCEV *FoldedRec =
-        getAddRecExpr(NewOps, AddRec->getLoop(),
-                      AddRec->getNoWrapFlags(SCEV::FlagNW));
-      AddRec = dyn_cast<SCEVAddRecExpr>(FoldedRec);
-      // The addrec may be folded to a nonrecurrence, for example, if the
-      // induction variable is multiplied by zero after constant folding. Go
-      // ahead and return the folded value.
-      if (!AddRec)
-        return FoldedRec;
-      break;
-    }
-
-    // If the scope is outside the addrec's loop, evaluate it by using the
-    // loop exit value of the addrec.
-    if (!AddRec->getLoop()->contains(L)) {
-      // To evaluate this recurrence, we need to know how many times the AddRec
-      // loop iterates.  Compute this now.
-      const SCEV *BackedgeTakenCount = getBackedgeTakenCount(AddRec->getLoop());
-      if (BackedgeTakenCount == getCouldNotCompute()) return AddRec;
-
-      // Then, evaluate the AddRec.
-      return AddRec->evaluateAtIteration(BackedgeTakenCount, *this);
-    }
-
-    return AddRec;
-  }
-
-  if (const SCEVZeroExtendExpr *Cast = dyn_cast<SCEVZeroExtendExpr>(V)) {
-    const SCEV *Op = getSCEVAtScope(Cast->getOperand(), L);
-    if (Op == Cast->getOperand())
-      return Cast;  // must be loop invariant
-    return getZeroExtendExpr(Op, Cast->getType());
-  }
-
-  if (const SCEVSignExtendExpr *Cast = dyn_cast<SCEVSignExtendExpr>(V)) {
-    const SCEV *Op = getSCEVAtScope(Cast->getOperand(), L);
-    if (Op == Cast->getOperand())
-      return Cast;  // must be loop invariant
-    return getSignExtendExpr(Op, Cast->getType());
-  }
-
-  if (const SCEVTruncateExpr *Cast = dyn_cast<SCEVTruncateExpr>(V)) {
-    const SCEV *Op = getSCEVAtScope(Cast->getOperand(), L);
-    if (Op == Cast->getOperand())
-      return Cast;  // must be loop invariant
-    return getTruncateExpr(Op, Cast->getType());
-  }
-
-  llvm_unreachable("Unknown SCEV type!");
-}
-
-const SCEV *ScalarEvolution::getSCEVAtScope(Value *V, const Loop *L) {
-  return getSCEVAtScope(getSCEV(V), L);
-}
-
-const SCEV *ScalarEvolution::stripInjectiveFunctions(const SCEV *S) const {
-  if (const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(S))
-    return stripInjectiveFunctions(ZExt->getOperand());
-  if (const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(S))
-    return stripInjectiveFunctions(SExt->getOperand());
-  return S;
-}
-
-/// Finds the minimum unsigned root of the following equation:
-///
-///     A * X = B (mod N)
-///
-/// where N = 2^BW and BW is the common bit width of A and B. The signedness of
-/// A and B isn't important.
-///
-/// If the equation does not have a solution, SCEVCouldNotCompute is returned.
-static const SCEV *SolveLinEquationWithOverflow(const APInt &A, const SCEV *B,
-                                               ScalarEvolution &SE) {
-  uint32_t BW = A.getBitWidth();
-  assert(BW == SE.getTypeSizeInBits(B->getType()));
-  assert(A != 0 && "A must be non-zero.");
-
-  // 1. D = gcd(A, N)
-  //
-  // The gcd of A and N may have only one prime factor: 2. The number of
-  // trailing zeros in A is its multiplicity
-  uint32_t Mult2 = A.countTrailingZeros();
-  // D = 2^Mult2
-
-  // 2. Check if B is divisible by D.
-  //
-  // B is divisible by D if and only if the multiplicity of prime factor 2 for B
-  // is not less than multiplicity of this prime factor for D.
-  if (SE.GetMinTrailingZeros(B) < Mult2)
-    return SE.getCouldNotCompute();
-
-  // 3. Compute I: the multiplicative inverse of (A / D) in arithmetic
-  // modulo (N / D).
-  //
-  // If D == 1, (N / D) == N == 2^BW, so we need one extra bit to represent
-  // (N / D) in general. The inverse itself always fits into BW bits, though,
-  // so we immediately truncate it.
-  APInt AD = A.lshr(Mult2).zext(BW + 1);  // AD = A / D
-  APInt Mod(BW + 1, 0);
-  Mod.setBit(BW - Mult2);  // Mod = N / D
-  APInt I = AD.multiplicativeInverse(Mod).trunc(BW);
-
-  // 4. Compute the minimum unsigned root of the equation:
-  // I * (B / D) mod (N / D)
-  // To simplify the computation, we factor out the divide by D:
-  // (I * B mod N) / D
-  const SCEV *D = SE.getConstant(APInt::getOneBitSet(BW, Mult2));
-  return SE.getUDivExactExpr(SE.getMulExpr(B, SE.getConstant(I)), D);
-}
-
-/// For a given quadratic addrec, generate coefficients of the corresponding
-/// quadratic equation, multiplied by a common value to ensure that they are
-/// integers.
-/// The returned value is a tuple { A, B, C, M, BitWidth }, where
-/// Ax^2 + Bx + C is the quadratic function, M is the value that A, B and C
-/// were multiplied by, and BitWidth is the bit width of the original addrec
-/// coefficients.
-/// This function returns None if the addrec coefficients are not compile-
-/// time constants.
-static Optional<std::tuple<APInt, APInt, APInt, APInt, unsigned>>
-GetQuadraticEquation(const SCEVAddRecExpr *AddRec) {
-  assert(AddRec->getNumOperands() == 3 && "This is not a quadratic chrec!");
-  const SCEVConstant *LC = dyn_cast<SCEVConstant>(AddRec->getOperand(0));
-  const SCEVConstant *MC = dyn_cast<SCEVConstant>(AddRec->getOperand(1));
-  const SCEVConstant *NC = dyn_cast<SCEVConstant>(AddRec->getOperand(2));
-  LLVM_DEBUG(dbgs() << __func__ << ": analyzing quadratic addrec: "
-                    << *AddRec << '\n');
-
-  // We currently can only solve this if the coefficients are constants.
-  if (!LC || !MC || !NC) {
-    LLVM_DEBUG(dbgs() << __func__ << ": coefficients are not constant\n");
-    return None;
-  }
-
-  APInt L = LC->getAPInt();
-  APInt M = MC->getAPInt();
-  APInt N = NC->getAPInt();
-  assert(!N.isNullValue() && "This is not a quadratic addrec");
-
-  unsigned BitWidth = LC->getAPInt().getBitWidth();
-  unsigned NewWidth = BitWidth + 1;
-  LLVM_DEBUG(dbgs() << __func__ << ": addrec coeff bw: "
-                    << BitWidth << '\n');
-  // The sign-extension (as opposed to a zero-extension) here matches the
-  // extension used in SolveQuadraticEquationWrap (with the same motivation).
-  N = N.sext(NewWidth);
-  M = M.sext(NewWidth);
-  L = L.sext(NewWidth);
-
-  // The increments are M, M+N, M+2N, ..., so the accumulated values are
-  //   L+M, (L+M)+(M+N), (L+M)+(M+N)+(M+2N), ..., that is,
-  //   L+M, L+2M+N, L+3M+3N, ...
-  // After n iterations the accumulated value Acc is L + nM + n(n-1)/2 N.
-  //
-  // The equation Acc = 0 is then
-  //   L + nM + n(n-1)/2 N = 0,  or  2L + 2M n + n(n-1) N = 0.
-  // In a quadratic form it becomes:
-  //   N n^2 + (2M-N) n + 2L = 0.
-
-  APInt A = N;
-  APInt B = 2 * M - A;
-  APInt C = 2 * L;
-  APInt T = APInt(NewWidth, 2);
-  LLVM_DEBUG(dbgs() << __func__ << ": equation " << A << "x^2 + " << B
-                    << "x + " << C << ", coeff bw: " << NewWidth
-                    << ", multiplied by " << T << '\n');
-  return std::make_tuple(A, B, C, T, BitWidth);
-}
-
-/// Helper function to compare optional APInts:
-/// (a) if X and Y both exist, return min(X, Y),
-/// (b) if neither X nor Y exist, return None,
-/// (c) if exactly one of X and Y exists, return that value.
-static Optional<APInt> MinOptional(Optional<APInt> X, Optional<APInt> Y) {
-  if (X.hasValue() && Y.hasValue()) {
-    unsigned W = std::max(X->getBitWidth(), Y->getBitWidth());
-    APInt XW = X->sextOrSelf(W);
-    APInt YW = Y->sextOrSelf(W);
-    return XW.slt(YW) ? *X : *Y;
-  }
-  if (!X.hasValue() && !Y.hasValue())
-    return None;
-  return X.hasValue() ? *X : *Y;
-}
-
-/// Helper function to truncate an optional APInt to a given BitWidth.
-/// When solving addrec-related equations, it is preferable to return a value
-/// that has the same bit width as the original addrec's coefficients. If the
-/// solution fits in the original bit width, truncate it (except for i1).
-/// Returning a value of a different bit width may inhibit some optimizations.
-///
-/// In general, a solution to a quadratic equation generated from an addrec
-/// may require BW+1 bits, where BW is the bit width of the addrec's
-/// coefficients. The reason is that the coefficients of the quadratic
-/// equation are BW+1 bits wide (to avoid truncation when converting from
-/// the addrec to the equation).
-static Optional<APInt> TruncIfPossible(Optional<APInt> X, unsigned BitWidth) {
-  if (!X.hasValue())
-    return None;
-  unsigned W = X->getBitWidth();
-  if (BitWidth > 1 && BitWidth < W && X->isIntN(BitWidth))
-    return X->trunc(BitWidth);
-  return X;
-}
-
-/// Let c(n) be the value of the quadratic chrec {L,+,M,+,N} after n
-/// iterations. The values L, M, N are assumed to be signed, and they
-/// should all have the same bit widths.
-/// Find the least n >= 0 such that c(n) = 0 in the arithmetic modulo 2^BW,
-/// where BW is the bit width of the addrec's coefficients.
-/// If the calculated value is a BW-bit integer (for BW > 1), it will be
-/// returned as such, otherwise the bit width of the returned value may
-/// be greater than BW.
-///
-/// This function returns None if
-/// (a) the addrec coefficients are not constant, or
-/// (b) SolveQuadraticEquationWrap was unable to find a solution. For cases
-///     like x^2 = 5, no integer solutions exist, in other cases an integer
-///     solution may exist, but SolveQuadraticEquationWrap may fail to find it.
-static Optional<APInt>
-SolveQuadraticAddRecExact(const SCEVAddRecExpr *AddRec, ScalarEvolution &SE) {
-  APInt A, B, C, M;
-  unsigned BitWidth;
-  auto T = GetQuadraticEquation(AddRec);
-  if (!T.hasValue())
-    return None;
-
-  std::tie(A, B, C, M, BitWidth) = *T;
-  LLVM_DEBUG(dbgs() << __func__ << ": solving for unsigned overflow\n");
-  Optional<APInt> X = APIntOps::SolveQuadraticEquationWrap(A, B, C, BitWidth+1);
-  if (!X.hasValue())
-    return None;
-
-  ConstantInt *CX = ConstantInt::get(SE.getContext(), *X);
-  ConstantInt *V = EvaluateConstantChrecAtConstant(AddRec, CX, SE);
-  if (!V->isZero())
-    return None;
-
-  return TruncIfPossible(X, BitWidth);
-}
-
-/// Let c(n) be the value of the quadratic chrec {0,+,M,+,N} after n
-/// iterations. The values M, N are assumed to be signed, and they
-/// should all have the same bit widths.
-/// Find the least n such that c(n) does not belong to the given range,
-/// while c(n-1) does.
-///
-/// This function returns None if
-/// (a) the addrec coefficients are not constant, or
-/// (b) SolveQuadraticEquationWrap was unable to find a solution for the
-///     bounds of the range.
-static Optional<APInt>
-SolveQuadraticAddRecRange(const SCEVAddRecExpr *AddRec,
-                          const ConstantRange &Range, ScalarEvolution &SE) {
-  assert(AddRec->getOperand(0)->isZero() &&
-         "Starting value of addrec should be 0");
-  LLVM_DEBUG(dbgs() << __func__ << ": solving boundary crossing for range "
-                    << Range << ", addrec " << *AddRec << '\n');
-  // This case is handled in getNumIterationsInRange. Here we can assume that
-  // we start in the range.
-  assert(Range.contains(APInt(SE.getTypeSizeInBits(AddRec->getType()), 0)) &&
-         "Addrec's initial value should be in range");
-
-  APInt A, B, C, M;
-  unsigned BitWidth;
-  auto T = GetQuadraticEquation(AddRec);
-  if (!T.hasValue())
-    return None;
-
-  // Be careful about the return value: there can be two reasons for not
-  // returning an actual number. First, if no solutions to the equations
-  // were found, and second, if the solutions don't leave the given range.
-  // The first case means that the actual solution is "unknown", the second
-  // means that it's known, but not valid. If the solution is unknown, we
-  // cannot make any conclusions.
-  // Return a pair: the optional solution and a flag indicating if the
-  // solution was found.
-  auto SolveForBoundary = [&](APInt Bound) -> std::pair<Optional<APInt>,bool> {
-    // Solve for signed overflow and unsigned overflow, pick the lower
-    // solution.
-    LLVM_DEBUG(dbgs() << "SolveQuadraticAddRecRange: checking boundary "
-                      << Bound << " (before multiplying by " << M << ")\n");
-    Bound *= M; // The quadratic equation multiplier.
-
-    Optional<APInt> SO = None;
-    if (BitWidth > 1) {
-      LLVM_DEBUG(dbgs() << "SolveQuadraticAddRecRange: solving for "
-                           "signed overflow\n");
-      SO = APIntOps::SolveQuadraticEquationWrap(A, B, -Bound, BitWidth);
-    }
-    LLVM_DEBUG(dbgs() << "SolveQuadraticAddRecRange: solving for "
-                         "unsigned overflow\n");
-    Optional<APInt> UO = APIntOps::SolveQuadraticEquationWrap(A, B, -Bound,
-                                                              BitWidth+1);
-
-    auto LeavesRange = [&] (const APInt &X) {
-      ConstantInt *C0 = ConstantInt::get(SE.getContext(), X);
-      ConstantInt *V0 = EvaluateConstantChrecAtConstant(AddRec, C0, SE);
-      if (Range.contains(V0->getValue()))
-        return false;
-      // X should be at least 1, so X-1 is non-negative.
-      ConstantInt *C1 = ConstantInt::get(SE.getContext(), X-1);
-      ConstantInt *V1 = EvaluateConstantChrecAtConstant(AddRec, C1, SE);
-      if (Range.contains(V1->getValue()))
-        return true;
-      return false;
-    };
-
-    // If SolveQuadraticEquationWrap returns None, it means that there can
-    // be a solution, but the function failed to find it. We cannot treat it
-    // as "no solution".
-    if (!SO.hasValue() || !UO.hasValue())
-      return { None, false };
-
-    // Check the smaller value first to see if it leaves the range.
-    // At this point, both SO and UO must have values.
-    Optional<APInt> Min = MinOptional(SO, UO);
-    if (LeavesRange(*Min))
-      return { Min, true };
-    Optional<APInt> Max = Min == SO ? UO : SO;
-    if (LeavesRange(*Max))
-      return { Max, true };
-
-    // Solutions were found, but were eliminated, hence the "true".
-    return { None, true };
-  };
-
-  std::tie(A, B, C, M, BitWidth) = *T;
-  // Lower bound is inclusive, subtract 1 to represent the exiting value.
-  APInt Lower = Range.getLower().sextOrSelf(A.getBitWidth()) - 1;
-  APInt Upper = Range.getUpper().sextOrSelf(A.getBitWidth());
-  auto SL = SolveForBoundary(Lower);
-  auto SU = SolveForBoundary(Upper);
-  // If any of the solutions was unknown, no meaninigful conclusions can
-  // be made.
-  if (!SL.second || !SU.second)
-    return None;
-
-  // Claim: The correct solution is not some value between Min and Max.
-  //
-  // Justification: Assuming that Min and Max are different values, one of
-  // them is when the first signed overflow happens, the other is when the
-  // first unsigned overflow happens. Crossing the range boundary is only
-  // possible via an overflow (treating 0 as a special case of it, modeling
-  // an overflow as crossing k*2^W for some k).
-  //
-  // The interesting case here is when Min was eliminated as an invalid
-  // solution, but Max was not. The argument is that if there was another
-  // overflow between Min and Max, it would also have been eliminated if
-  // it was considered.
-  //
-  // For a given boundary, it is possible to have two overflows of the same
-  // type (signed/unsigned) without having the other type in between: this
-  // can happen when the vertex of the parabola is between the iterations
-  // corresponding to the overflows. This is only possible when the two
-  // overflows cross k*2^W for the same k. In such case, if the second one
-  // left the range (and was the first one to do so), the first overflow
-  // would have to enter the range, which would mean that either we had left
-  // the range before or that we started outside of it. Both of these cases
-  // are contradictions.
-  //
-  // Claim: In the case where SolveForBoundary returns None, the correct
-  // solution is not some value between the Max for this boundary and the
-  // Min of the other boundary.
-  //
-  // Justification: Assume that we had such Max_A and Min_B corresponding
-  // to range boundaries A and B and such that Max_A < Min_B. If there was
-  // a solution between Max_A and Min_B, it would have to be caused by an
-  // overflow corresponding to either A or B. It cannot correspond to B,
-  // since Min_B is the first occurrence of such an overflow. If it
-  // corresponded to A, it would have to be either a signed or an unsigned
-  // overflow that is larger than both eliminated overflows for A. But
-  // between the eliminated overflows and this overflow, the values would
-  // cover the entire value space, thus crossing the other boundary, which
-  // is a contradiction.
-
-  return TruncIfPossible(MinOptional(SL.first, SU.first), BitWidth);
-}
-
-ScalarEvolution::ExitLimit
-ScalarEvolution::howFarToZero(const SCEV *V, const Loop *L, bool ControlsExit,
-                              bool AllowPredicates) {
-
-  // This is only used for loops with a "x != y" exit test. The exit condition
-  // is now expressed as a single expression, V = x-y. So the exit test is
-  // effectively V != 0.  We know and take advantage of the fact that this
-  // expression only being used in a comparison by zero context.
-
-  SmallPtrSet<const SCEVPredicate *, 4> Predicates;
-  // If the value is a constant
-  if (const SCEVConstant *C = dyn_cast<SCEVConstant>(V)) {
-    // If the value is already zero, the branch will execute zero times.
-    if (C->getValue()->isZero()) return C;
-    return getCouldNotCompute();  // Otherwise it will loop infinitely.
-  }
-
-  const SCEVAddRecExpr *AddRec =
-      dyn_cast<SCEVAddRecExpr>(stripInjectiveFunctions(V));
-
-  if (!AddRec && AllowPredicates)
-    // Try to make this an AddRec using runtime tests, in the first X
-    // iterations of this loop, where X is the SCEV expression found by the
-    // algorithm below.
-    AddRec = convertSCEVToAddRecWithPredicates(V, L, Predicates);
-
-  if (!AddRec || AddRec->getLoop() != L)
-    return getCouldNotCompute();
-
-  // If this is a quadratic (3-term) AddRec {L,+,M,+,N}, find the roots of
-  // the quadratic equation to solve it.
-  if (AddRec->isQuadratic() && AddRec->getType()->isIntegerTy()) {
-    // We can only use this value if the chrec ends up with an exact zero
-    // value at this index.  When solving for "X*X != 5", for example, we
-    // should not accept a root of 2.
-    if (auto S = SolveQuadraticAddRecExact(AddRec, *this)) {
-      const auto *R = cast<SCEVConstant>(getConstant(S.getValue()));
-      return ExitLimit(R, R, false, Predicates);
-    }
-    return getCouldNotCompute();
-  }
-
-  // Otherwise we can only handle this if it is affine.
-  if (!AddRec->isAffine())
-    return getCouldNotCompute();
-
-  // If this is an affine expression, the execution count of this branch is
-  // the minimum unsigned root of the following equation:
-  //
-  //     Start + Step*N = 0 (mod 2^BW)
-  //
-  // equivalent to:
-  //
-  //             Step*N = -Start (mod 2^BW)
-  //
-  // where BW is the common bit width of Start and Step.
-
-  // Get the initial value for the loop.
-  const SCEV *Start = getSCEVAtScope(AddRec->getStart(), L->getParentLoop());
-  const SCEV *Step = getSCEVAtScope(AddRec->getOperand(1), L->getParentLoop());
-
-  // For now we handle only constant steps.
-  //
-  // TODO: Handle a nonconstant Step given AddRec<NUW>. If the
-  // AddRec is NUW, then (in an unsigned sense) it cannot be counting up to wrap
-  // to 0, it must be counting down to equal 0. Consequently, N = Start / -Step.
-  // We have not yet seen any such cases.
-  const SCEVConstant *StepC = dyn_cast<SCEVConstant>(Step);
-  if (!StepC || StepC->getValue()->isZero())
-    return getCouldNotCompute();
-
-  // For positive steps (counting up until unsigned overflow):
-  //   N = -Start/Step (as unsigned)
-  // For negative steps (counting down to zero):
-  //   N = Start/-Step
-  // First compute the unsigned distance from zero in the direction of Step.
-  bool CountDown = StepC->getAPInt().isNegative();
-  const SCEV *Distance = CountDown ? Start : getNegativeSCEV(Start);
-
-  // Handle unitary steps, which cannot wraparound.
-  // 1*N = -Start; -1*N = Start (mod 2^BW), so:
-  //   N = Distance (as unsigned)
-  if (StepC->getValue()->isOne() || StepC->getValue()->isMinusOne()) {
-    APInt MaxBECount = getUnsignedRangeMax(Distance);
-
-    // When a loop like "for (int i = 0; i != n; ++i) { /* body */ }" is rotated,
-    // we end up with a loop whose backedge-taken count is n - 1.  Detect this
-    // case, and see if we can improve the bound.
-    //
-    // Explicitly handling this here is necessary because getUnsignedRange
-    // isn't context-sensitive; it doesn't know that we only care about the
-    // range inside the loop.
-    const SCEV *Zero = getZero(Distance->getType());
-    const SCEV *One = getOne(Distance->getType());
-    const SCEV *DistancePlusOne = getAddExpr(Distance, One);
-    if (isLoopEntryGuardedByCond(L, ICmpInst::ICMP_NE, DistancePlusOne, Zero)) {
-      // If Distance + 1 doesn't overflow, we can compute the maximum distance
-      // as "unsigned_max(Distance + 1) - 1".
-      ConstantRange CR = getUnsignedRange(DistancePlusOne);
-      MaxBECount = APIntOps::umin(MaxBECount, CR.getUnsignedMax() - 1);
-    }
-    return ExitLimit(Distance, getConstant(MaxBECount), false, Predicates);
-  }
-
-  // If the condition controls loop exit (the loop exits only if the expression
-  // is true) and the addition is no-wrap we can use unsigned divide to
-  // compute the backedge count.  In this case, the step may not divide the
-  // distance, but we don't care because if the condition is "missed" the loop
-  // will have undefined behavior due to wrapping.
-  if (ControlsExit && AddRec->hasNoSelfWrap() &&
-      loopHasNoAbnormalExits(AddRec->getLoop())) {
-    const SCEV *Exact =
-        getUDivExpr(Distance, CountDown ? getNegativeSCEV(Step) : Step);
-    const SCEV *Max =
-        Exact == getCouldNotCompute()
-            ? Exact
-            : getConstant(getUnsignedRangeMax(Exact));
-    return ExitLimit(Exact, Max, false, Predicates);
-  }
-
-  // Solve the general equation.
-  const SCEV *E = SolveLinEquationWithOverflow(StepC->getAPInt(),
-                                               getNegativeSCEV(Start), *this);
-  const SCEV *M = E == getCouldNotCompute()
-                      ? E
-                      : getConstant(getUnsignedRangeMax(E));
-  return ExitLimit(E, M, false, Predicates);
-}
-
-ScalarEvolution::ExitLimit
-ScalarEvolution::howFarToNonZero(const SCEV *V, const Loop *L) {
-  // Loops that look like: while (X == 0) are very strange indeed.  We don't
-  // handle them yet except for the trivial case.  This could be expanded in the
-  // future as needed.
-
-  // If the value is a constant, check to see if it is known to be non-zero
-  // already.  If so, the backedge will execute zero times.
-  if (const SCEVConstant *C = dyn_cast<SCEVConstant>(V)) {
-    if (!C->getValue()->isZero())
-      return getZero(C->getType());
-    return getCouldNotCompute();  // Otherwise it will loop infinitely.
-  }
-
-  // We could implement others, but I really doubt anyone writes loops like
-  // this, and if they did, they would already be constant folded.
-  return getCouldNotCompute();
-}
-
-std::pair<BasicBlock *, BasicBlock *>
-ScalarEvolution::getPredecessorWithUniqueSuccessorForBB(BasicBlock *BB) {
-  // If the block has a unique predecessor, then there is no path from the
-  // predecessor to the block that does not go through the direct edge
-  // from the predecessor to the block.
-  if (BasicBlock *Pred = BB->getSinglePredecessor())
-    return {Pred, BB};
-
-  // A loop's header is defined to be a block that dominates the loop.
-  // If the header has a unique predecessor outside the loop, it must be
-  // a block that has exactly one successor that can reach the loop.
-  if (Loop *L = LI.getLoopFor(BB))
-    return {L->getLoopPredecessor(), L->getHeader()};
-
-  return {nullptr, nullptr};
-}
-
-/// SCEV structural equivalence is usually sufficient for testing whether two
-/// expressions are equal, however for the purposes of looking for a condition
-/// guarding a loop, it can be useful to be a little more general, since a
-/// front-end may have replicated the controlling expression.
-static bool HasSameValue(const SCEV *A, const SCEV *B) {
-  // Quick check to see if they are the same SCEV.
-  if (A == B) return true;
-
-  auto ComputesEqualValues = [](const Instruction *A, const Instruction *B) {
-    // Not all instructions that are "identical" compute the same value.  For
-    // instance, two distinct alloca instructions allocating the same type are
-    // identical and do not read memory; but compute distinct values.
-    return A->isIdenticalTo(B) && (isa<BinaryOperator>(A) || isa<GetElementPtrInst>(A));
-  };
-
-  // Otherwise, if they're both SCEVUnknown, it's possible that they hold
-  // two different instructions with the same value. Check for this case.
-  if (const SCEVUnknown *AU = dyn_cast<SCEVUnknown>(A))
-    if (const SCEVUnknown *BU = dyn_cast<SCEVUnknown>(B))
-      if (const Instruction *AI = dyn_cast<Instruction>(AU->getValue()))
-        if (const Instruction *BI = dyn_cast<Instruction>(BU->getValue()))
-          if (ComputesEqualValues(AI, BI))
-            return true;
-
-  // Otherwise assume they may have a different value.
-  return false;
-}
-
-bool ScalarEvolution::SimplifyICmpOperands(ICmpInst::Predicate &Pred,
-                                           const SCEV *&LHS, const SCEV *&RHS,
-                                           unsigned Depth) {
-  bool Changed = false;
-  // Simplifies ICMP to trivial true or false by turning it into '0 == 0' or
-  // '0 != 0'.
-  auto TrivialCase = [&](bool TriviallyTrue) {
-    LHS = RHS = getConstant(ConstantInt::getFalse(getContext()));
-    Pred = TriviallyTrue ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE;
-    return true;
-  };
-  // If we hit the max recursion limit bail out.
-  if (Depth >= 3)
-    return false;
-
-  // Canonicalize a constant to the right side.
-  if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(LHS)) {
-    // Check for both operands constant.
-    if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) {
-      if (ConstantExpr::getICmp(Pred,
-                                LHSC->getValue(),
-                                RHSC->getValue())->isNullValue())
-        return TrivialCase(false);
-      else
-        return TrivialCase(true);
-    }
-    // Otherwise swap the operands to put the constant on the right.
-    std::swap(LHS, RHS);
-    Pred = ICmpInst::getSwappedPredicate(Pred);
-    Changed = true;
-  }
-
-  // If we're comparing an addrec with a value which is loop-invariant in the
-  // addrec's loop, put the addrec on the left. Also make a dominance check,
-  // as both operands could be addrecs loop-invariant in each other's loop.
-  if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(RHS)) {
-    const Loop *L = AR->getLoop();
-    if (isLoopInvariant(LHS, L) && properlyDominates(LHS, L->getHeader())) {
-      std::swap(LHS, RHS);
-      Pred = ICmpInst::getSwappedPredicate(Pred);
-      Changed = true;
-    }
-  }
-
-  // If there's a constant operand, canonicalize comparisons with boundary
-  // cases, and canonicalize *-or-equal comparisons to regular comparisons.
-  if (const SCEVConstant *RC = dyn_cast<SCEVConstant>(RHS)) {
-    const APInt &RA = RC->getAPInt();
-
-    bool SimplifiedByConstantRange = false;
-
-    if (!ICmpInst::isEquality(Pred)) {
-      ConstantRange ExactCR = ConstantRange::makeExactICmpRegion(Pred, RA);
-      if (ExactCR.isFullSet())
-        return TrivialCase(true);
-      else if (ExactCR.isEmptySet())
-        return TrivialCase(false);
-
-      APInt NewRHS;
-      CmpInst::Predicate NewPred;
-      if (ExactCR.getEquivalentICmp(NewPred, NewRHS) &&
-          ICmpInst::isEquality(NewPred)) {
-        // We were able to convert an inequality to an equality.
-        Pred = NewPred;
-        RHS = getConstant(NewRHS);
-        Changed = SimplifiedByConstantRange = true;
-      }
-    }
-
-    if (!SimplifiedByConstantRange) {
-      switch (Pred) {
-      default:
-        break;
-      case ICmpInst::ICMP_EQ:
-      case ICmpInst::ICMP_NE:
-        // Fold ((-1) * %a) + %b == 0 (equivalent to %b-%a == 0) into %a == %b.
-        if (!RA)
-          if (const SCEVAddExpr *AE = dyn_cast<SCEVAddExpr>(LHS))
-            if (const SCEVMulExpr *ME =
-                    dyn_cast<SCEVMulExpr>(AE->getOperand(0)))
-              if (AE->getNumOperands() == 2 && ME->getNumOperands() == 2 &&
-                  ME->getOperand(0)->isAllOnesValue()) {
-                RHS = AE->getOperand(1);
-                LHS = ME->getOperand(1);
-                Changed = true;
-              }
-        break;
-
-
-        // The "Should have been caught earlier!" messages refer to the fact
-        // that the ExactCR.isFullSet() or ExactCR.isEmptySet() check above
-        // should have fired on the corresponding cases, and canonicalized the
-        // check to trivial case.
-
-      case ICmpInst::ICMP_UGE:
-        assert(!RA.isMinValue() && "Should have been caught earlier!");
-        Pred = ICmpInst::ICMP_UGT;
-        RHS = getConstant(RA - 1);
-        Changed = true;
-        break;
-      case ICmpInst::ICMP_ULE:
-        assert(!RA.isMaxValue() && "Should have been caught earlier!");
-        Pred = ICmpInst::ICMP_ULT;
-        RHS = getConstant(RA + 1);
-        Changed = true;
-        break;
-      case ICmpInst::ICMP_SGE:
-        assert(!RA.isMinSignedValue() && "Should have been caught earlier!");
-        Pred = ICmpInst::ICMP_SGT;
-        RHS = getConstant(RA - 1);
-        Changed = true;
-        break;
-      case ICmpInst::ICMP_SLE:
-        assert(!RA.isMaxSignedValue() && "Should have been caught earlier!");
-        Pred = ICmpInst::ICMP_SLT;
-        RHS = getConstant(RA + 1);
-        Changed = true;
-        break;
-      }
-    }
-  }
-
-  // Check for obvious equality.
-  if (HasSameValue(LHS, RHS)) {
-    if (ICmpInst::isTrueWhenEqual(Pred))
-      return TrivialCase(true);
-    if (ICmpInst::isFalseWhenEqual(Pred))
-      return TrivialCase(false);
-  }
-
-  // If possible, canonicalize GE/LE comparisons to GT/LT comparisons, by
-  // adding or subtracting 1 from one of the operands.
-  switch (Pred) {
-  case ICmpInst::ICMP_SLE:
-    if (!getSignedRangeMax(RHS).isMaxSignedValue()) {
-      RHS = getAddExpr(getConstant(RHS->getType(), 1, true), RHS,
-                       SCEV::FlagNSW);
-      Pred = ICmpInst::ICMP_SLT;
-      Changed = true;
-    } else if (!getSignedRangeMin(LHS).isMinSignedValue()) {
-      LHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), LHS,
-                       SCEV::FlagNSW);
-      Pred = ICmpInst::ICMP_SLT;
-      Changed = true;
-    }
-    break;
-  case ICmpInst::ICMP_SGE:
-    if (!getSignedRangeMin(RHS).isMinSignedValue()) {
-      RHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), RHS,
-                       SCEV::FlagNSW);
-      Pred = ICmpInst::ICMP_SGT;
-      Changed = true;
-    } else if (!getSignedRangeMax(LHS).isMaxSignedValue()) {
-      LHS = getAddExpr(getConstant(RHS->getType(), 1, true), LHS,
-                       SCEV::FlagNSW);
-      Pred = ICmpInst::ICMP_SGT;
-      Changed = true;
-    }
-    break;
-  case ICmpInst::ICMP_ULE:
-    if (!getUnsignedRangeMax(RHS).isMaxValue()) {
-      RHS = getAddExpr(getConstant(RHS->getType(), 1, true), RHS,
-                       SCEV::FlagNUW);
-      Pred = ICmpInst::ICMP_ULT;
-      Changed = true;
-    } else if (!getUnsignedRangeMin(LHS).isMinValue()) {
-      LHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), LHS);
-      Pred = ICmpInst::ICMP_ULT;
-      Changed = true;
-    }
-    break;
-  case ICmpInst::ICMP_UGE:
-    if (!getUnsignedRangeMin(RHS).isMinValue()) {
-      RHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), RHS);
-      Pred = ICmpInst::ICMP_UGT;
-      Changed = true;
-    } else if (!getUnsignedRangeMax(LHS).isMaxValue()) {
-      LHS = getAddExpr(getConstant(RHS->getType(), 1, true), LHS,
-                       SCEV::FlagNUW);
-      Pred = ICmpInst::ICMP_UGT;
-      Changed = true;
-    }
-    break;
-  default:
-    break;
-  }
-
-  // TODO: More simplifications are possible here.
-
-  // Recursively simplify until we either hit a recursion limit or nothing
-  // changes.
-  if (Changed)
-    return SimplifyICmpOperands(Pred, LHS, RHS, Depth+1);
-
-  return Changed;
-}
-
-bool ScalarEvolution::isKnownNegative(const SCEV *S) {
-  return getSignedRangeMax(S).isNegative();
-}
-
-bool ScalarEvolution::isKnownPositive(const SCEV *S) {
-  return getSignedRangeMin(S).isStrictlyPositive();
-}
-
-bool ScalarEvolution::isKnownNonNegative(const SCEV *S) {
-  return !getSignedRangeMin(S).isNegative();
-}
-
-bool ScalarEvolution::isKnownNonPositive(const SCEV *S) {
-  return !getSignedRangeMax(S).isStrictlyPositive();
-}
-
-bool ScalarEvolution::isKnownNonZero(const SCEV *S) {
-  return isKnownNegative(S) || isKnownPositive(S);
-}
-
-std::pair<const SCEV *, const SCEV *>
-ScalarEvolution::SplitIntoInitAndPostInc(const Loop *L, const SCEV *S) {
-  // Compute SCEV on entry of loop L.
-  const SCEV *Start = SCEVInitRewriter::rewrite(S, L, *this);
-  if (Start == getCouldNotCompute())
-    return { Start, Start };
-  // Compute post increment SCEV for loop L.
-  const SCEV *PostInc = SCEVPostIncRewriter::rewrite(S, L, *this);
-  assert(PostInc != getCouldNotCompute() && "Unexpected could not compute");
-  return { Start, PostInc };
-}
-
-bool ScalarEvolution::isKnownViaInduction(ICmpInst::Predicate Pred,
-                                          const SCEV *LHS, const SCEV *RHS) {
-  // First collect all loops.
-  SmallPtrSet<const Loop *, 8> LoopsUsed;
-  getUsedLoops(LHS, LoopsUsed);
-  getUsedLoops(RHS, LoopsUsed);
-
-  if (LoopsUsed.empty())
-    return false;
-
-  // Domination relationship must be a linear order on collected loops.
-#ifndef NDEBUG
-  for (auto *L1 : LoopsUsed)
-    for (auto *L2 : LoopsUsed)
-      assert((DT.dominates(L1->getHeader(), L2->getHeader()) ||
-              DT.dominates(L2->getHeader(), L1->getHeader())) &&
-             "Domination relationship is not a linear order");
-#endif
-
-  const Loop *MDL =
-      *std::max_element(LoopsUsed.begin(), LoopsUsed.end(),
-                        [&](const Loop *L1, const Loop *L2) {
-         return DT.properlyDominates(L1->getHeader(), L2->getHeader());
-       });
-
-  // Get init and post increment value for LHS.
-  auto SplitLHS = SplitIntoInitAndPostInc(MDL, LHS);
-  // if LHS contains unknown non-invariant SCEV then bail out.
-  if (SplitLHS.first == getCouldNotCompute())
-    return false;
-  assert (SplitLHS.second != getCouldNotCompute() && "Unexpected CNC");
-  // Get init and post increment value for RHS.
-  auto SplitRHS = SplitIntoInitAndPostInc(MDL, RHS);
-  // if RHS contains unknown non-invariant SCEV then bail out.
-  if (SplitRHS.first == getCouldNotCompute())
-    return false;
-  assert (SplitRHS.second != getCouldNotCompute() && "Unexpected CNC");
-  // It is possible that init SCEV contains an invariant load but it does
-  // not dominate MDL and is not available at MDL loop entry, so we should
-  // check it here.
-  if (!isAvailableAtLoopEntry(SplitLHS.first, MDL) ||
-      !isAvailableAtLoopEntry(SplitRHS.first, MDL))
-    return false;
-
-  return isLoopEntryGuardedByCond(MDL, Pred, SplitLHS.first, SplitRHS.first) &&
-         isLoopBackedgeGuardedByCond(MDL, Pred, SplitLHS.second,
-                                     SplitRHS.second);
-}
-
-bool ScalarEvolution::isKnownPredicate(ICmpInst::Predicate Pred,
-                                       const SCEV *LHS, const SCEV *RHS) {
-  // Canonicalize the inputs first.
-  (void)SimplifyICmpOperands(Pred, LHS, RHS);
-
-  if (isKnownViaInduction(Pred, LHS, RHS))
-    return true;
-
-  if (isKnownPredicateViaSplitting(Pred, LHS, RHS))
-    return true;
-
-  // Otherwise see what can be done with some simple reasoning.
-  return isKnownViaNonRecursiveReasoning(Pred, LHS, RHS);
-}
-
-bool ScalarEvolution::isKnownOnEveryIteration(ICmpInst::Predicate Pred,
-                                              const SCEVAddRecExpr *LHS,
-                                              const SCEV *RHS) {
-  const Loop *L = LHS->getLoop();
-  return isLoopEntryGuardedByCond(L, Pred, LHS->getStart(), RHS) &&
-         isLoopBackedgeGuardedByCond(L, Pred, LHS->getPostIncExpr(*this), RHS);
-}
-
-bool ScalarEvolution::isMonotonicPredicate(const SCEVAddRecExpr *LHS,
-                                           ICmpInst::Predicate Pred,
-                                           bool &Increasing) {
-  bool Result = isMonotonicPredicateImpl(LHS, Pred, Increasing);
-
-#ifndef NDEBUG
-  // Verify an invariant: inverting the predicate should turn a monotonically
-  // increasing change to a monotonically decreasing one, and vice versa.
-  bool IncreasingSwapped;
-  bool ResultSwapped = isMonotonicPredicateImpl(
-      LHS, ICmpInst::getSwappedPredicate(Pred), IncreasingSwapped);
-
-  assert(Result == ResultSwapped && "should be able to analyze both!");
-  if (ResultSwapped)
-    assert(Increasing == !IncreasingSwapped &&
-           "monotonicity should flip as we flip the predicate");
-#endif
-
-  return Result;
-}
-
-bool ScalarEvolution::isMonotonicPredicateImpl(const SCEVAddRecExpr *LHS,
-                                               ICmpInst::Predicate Pred,
-                                               bool &Increasing) {
-
-  // A zero step value for LHS means the induction variable is essentially a
-  // loop invariant value. We don't really depend on the predicate actually
-  // flipping from false to true (for increasing predicates, and the other way
-  // around for decreasing predicates), all we care about is that *if* the
-  // predicate changes then it only changes from false to true.
-  //
-  // A zero step value in itself is not very useful, but there may be places
-  // where SCEV can prove X >= 0 but not prove X > 0, so it is helpful to be
-  // as general as possible.
-
-  switch (Pred) {
-  default:
-    return false; // Conservative answer
-
-  case ICmpInst::ICMP_UGT:
-  case ICmpInst::ICMP_UGE:
-  case ICmpInst::ICMP_ULT:
-  case ICmpInst::ICMP_ULE:
-    if (!LHS->hasNoUnsignedWrap())
-      return false;
-
-    Increasing = Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_UGE;
-    return true;
-
-  case ICmpInst::ICMP_SGT:
-  case ICmpInst::ICMP_SGE:
-  case ICmpInst::ICMP_SLT:
-  case ICmpInst::ICMP_SLE: {
-    if (!LHS->hasNoSignedWrap())
-      return false;
-
-    const SCEV *Step = LHS->getStepRecurrence(*this);
-
-    if (isKnownNonNegative(Step)) {
-      Increasing = Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE;
-      return true;
-    }
-
-    if (isKnownNonPositive(Step)) {
-      Increasing = Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SLE;
-      return true;
-    }
-
-    return false;
-  }
-
-  }
-
-  llvm_unreachable("switch has default clause!");
-}
-
-bool ScalarEvolution::isLoopInvariantPredicate(
-    ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS, const Loop *L,
-    ICmpInst::Predicate &InvariantPred, const SCEV *&InvariantLHS,
-    const SCEV *&InvariantRHS) {
-
-  // If there is a loop-invariant, force it into the RHS, otherwise bail out.
-  if (!isLoopInvariant(RHS, L)) {
-    if (!isLoopInvariant(LHS, L))
-      return false;
-
-    std::swap(LHS, RHS);
-    Pred = ICmpInst::getSwappedPredicate(Pred);
-  }
-
-  const SCEVAddRecExpr *ArLHS = dyn_cast<SCEVAddRecExpr>(LHS);
-  if (!ArLHS || ArLHS->getLoop() != L)
-    return false;
-
-  bool Increasing;
-  if (!isMonotonicPredicate(ArLHS, Pred, Increasing))
-    return false;
-
-  // If the predicate "ArLHS `Pred` RHS" monotonically increases from false to
-  // true as the loop iterates, and the backedge is control dependent on
-  // "ArLHS `Pred` RHS" == true then we can reason as follows:
-  //
-  //   * if the predicate was false in the first iteration then the predicate
-  //     is never evaluated again, since the loop exits without taking the
-  //     backedge.
-  //   * if the predicate was true in the first iteration then it will
-  //     continue to be true for all future iterations since it is
-  //     monotonically increasing.
-  //
-  // For both the above possibilities, we can replace the loop varying
-  // predicate with its value on the first iteration of the loop (which is
-  // loop invariant).
-  //
-  // A similar reasoning applies for a monotonically decreasing predicate, by
-  // replacing true with false and false with true in the above two bullets.
-
-  auto P = Increasing ? Pred : ICmpInst::getInversePredicate(Pred);
-
-  if (!isLoopBackedgeGuardedByCond(L, P, LHS, RHS))
-    return false;
-
-  InvariantPred = Pred;
-  InvariantLHS = ArLHS->getStart();
-  InvariantRHS = RHS;
-  return true;
-}
-
-bool ScalarEvolution::isKnownPredicateViaConstantRanges(
-    ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS) {
-  if (HasSameValue(LHS, RHS))
-    return ICmpInst::isTrueWhenEqual(Pred);
-
-  // This code is split out from isKnownPredicate because it is called from
-  // within isLoopEntryGuardedByCond.
-
-  auto CheckRanges =
-      [&](const ConstantRange &RangeLHS, const ConstantRange &RangeRHS) {
-    return ConstantRange::makeSatisfyingICmpRegion(Pred, RangeRHS)
-        .contains(RangeLHS);
-  };
-
-  // The check at the top of the function catches the case where the values are
-  // known to be equal.
-  if (Pred == CmpInst::ICMP_EQ)
-    return false;
-
-  if (Pred == CmpInst::ICMP_NE)
-    return CheckRanges(getSignedRange(LHS), getSignedRange(RHS)) ||
-           CheckRanges(getUnsignedRange(LHS), getUnsignedRange(RHS)) ||
-           isKnownNonZero(getMinusSCEV(LHS, RHS));
-
-  if (CmpInst::isSigned(Pred))
-    return CheckRanges(getSignedRange(LHS), getSignedRange(RHS));
-
-  return CheckRanges(getUnsignedRange(LHS), getUnsignedRange(RHS));
-}
-
-bool ScalarEvolution::isKnownPredicateViaNoOverflow(ICmpInst::Predicate Pred,
-                                                    const SCEV *LHS,
-                                                    const SCEV *RHS) {
-  // Match Result to (X + Y)<ExpectedFlags> where Y is a constant integer.
-  // Return Y via OutY.
-  auto MatchBinaryAddToConst =
-      [this](const SCEV *Result, const SCEV *X, APInt &OutY,
-             SCEV::NoWrapFlags ExpectedFlags) {
-    const SCEV *NonConstOp, *ConstOp;
-    SCEV::NoWrapFlags FlagsPresent;
-
-    if (!splitBinaryAdd(Result, ConstOp, NonConstOp, FlagsPresent) ||
-        !isa<SCEVConstant>(ConstOp) || NonConstOp != X)
-      return false;
-
-    OutY = cast<SCEVConstant>(ConstOp)->getAPInt();
-    return (FlagsPresent & ExpectedFlags) == ExpectedFlags;
-  };
-
-  APInt C;
-
-  switch (Pred) {
-  default:
-    break;
-
-  case ICmpInst::ICMP_SGE:
-    std::swap(LHS, RHS);
-    LLVM_FALLTHROUGH;
-  case ICmpInst::ICMP_SLE:
-    // X s<= (X + C)<nsw> if C >= 0
-    if (MatchBinaryAddToConst(RHS, LHS, C, SCEV::FlagNSW) && C.isNonNegative())
-      return true;
-
-    // (X + C)<nsw> s<= X if C <= 0
-    if (MatchBinaryAddToConst(LHS, RHS, C, SCEV::FlagNSW) &&
-        !C.isStrictlyPositive())
-      return true;
-    break;
-
-  case ICmpInst::ICMP_SGT:
-    std::swap(LHS, RHS);
-    LLVM_FALLTHROUGH;
-  case ICmpInst::ICMP_SLT:
-    // X s< (X + C)<nsw> if C > 0
-    if (MatchBinaryAddToConst(RHS, LHS, C, SCEV::FlagNSW) &&
-        C.isStrictlyPositive())
-      return true;
-
-    // (X + C)<nsw> s< X if C < 0
-    if (MatchBinaryAddToConst(LHS, RHS, C, SCEV::FlagNSW) && C.isNegative())
-      return true;
-    break;
-  }
-
-  return false;
-}
-
-bool ScalarEvolution::isKnownPredicateViaSplitting(ICmpInst::Predicate Pred,
-                                                   const SCEV *LHS,
-                                                   const SCEV *RHS) {
-  if (Pred != ICmpInst::ICMP_ULT || ProvingSplitPredicate)
-    return false;
-
-  // Allowing arbitrary number of activations of isKnownPredicateViaSplitting on
-  // the stack can result in exponential time complexity.
-  SaveAndRestore<bool> Restore(ProvingSplitPredicate, true);
-
-  // If L >= 0 then I `ult` L <=> I >= 0 && I `slt` L
-  //
-  // To prove L >= 0 we use isKnownNonNegative whereas to prove I >= 0 we use
-  // isKnownPredicate.  isKnownPredicate is more powerful, but also more
-  // expensive; and using isKnownNonNegative(RHS) is sufficient for most of the
-  // interesting cases seen in practice.  We can consider "upgrading" L >= 0 to
-  // use isKnownPredicate later if needed.
-  return isKnownNonNegative(RHS) &&
-         isKnownPredicate(CmpInst::ICMP_SGE, LHS, getZero(LHS->getType())) &&
-         isKnownPredicate(CmpInst::ICMP_SLT, LHS, RHS);
-}
-
-bool ScalarEvolution::isImpliedViaGuard(BasicBlock *BB,
-                                        ICmpInst::Predicate Pred,
-                                        const SCEV *LHS, const SCEV *RHS) {
-  // No need to even try if we know the module has no guards.
-  if (!HasGuards)
-    return false;
-
-  return any_of(*BB, [&](Instruction &I) {
-    using namespace llvm::PatternMatch;
-
-    Value *Condition;
-    return match(&I, m_Intrinsic<Intrinsic::experimental_guard>(
-                         m_Value(Condition))) &&
-           isImpliedCond(Pred, LHS, RHS, Condition, false);
-  });
-}
-
-/// isLoopBackedgeGuardedByCond - Test whether the backedge of the loop is
-/// protected by a conditional between LHS and RHS.  This is used to
-/// to eliminate casts.
-bool
-ScalarEvolution::isLoopBackedgeGuardedByCond(const Loop *L,
-                                             ICmpInst::Predicate Pred,
-                                             const SCEV *LHS, const SCEV *RHS) {
-  // Interpret a null as meaning no loop, where there is obviously no guard
-  // (interprocedural conditions notwithstanding).
-  if (!L) return true;
-
-  if (VerifyIR)
-    assert(!verifyFunction(*L->getHeader()->getParent(), &dbgs()) &&
-           "This cannot be done on broken IR!");
-
-
-  if (isKnownViaNonRecursiveReasoning(Pred, LHS, RHS))
-    return true;
-
-  BasicBlock *Latch = L->getLoopLatch();
-  if (!Latch)
-    return false;
-
-  BranchInst *LoopContinuePredicate =
-    dyn_cast<BranchInst>(Latch->getTerminator());
-  if (LoopContinuePredicate && LoopContinuePredicate->isConditional() &&
-      isImpliedCond(Pred, LHS, RHS,
-                    LoopContinuePredicate->getCondition(),
-                    LoopContinuePredicate->getSuccessor(0) != L->getHeader()))
-    return true;
-
-  // We don't want more than one activation of the following loops on the stack
-  // -- that can lead to O(n!) time complexity.
-  if (WalkingBEDominatingConds)
-    return false;
-
-  SaveAndRestore<bool> ClearOnExit(WalkingBEDominatingConds, true);
-
-  // See if we can exploit a trip count to prove the predicate.
-  const auto &BETakenInfo = getBackedgeTakenInfo(L);
-  const SCEV *LatchBECount = BETakenInfo.getExact(Latch, this);
-  if (LatchBECount != getCouldNotCompute()) {
-    // We know that Latch branches back to the loop header exactly
-    // LatchBECount times.  This means the backdege condition at Latch is
-    // equivalent to  "{0,+,1} u< LatchBECount".
-    Type *Ty = LatchBECount->getType();
-    auto NoWrapFlags = SCEV::NoWrapFlags(SCEV::FlagNUW | SCEV::FlagNW);
-    const SCEV *LoopCounter =
-      getAddRecExpr(getZero(Ty), getOne(Ty), L, NoWrapFlags);
-    if (isImpliedCond(Pred, LHS, RHS, ICmpInst::ICMP_ULT, LoopCounter,
-                      LatchBECount))
-      return true;
-  }
-
-  // Check conditions due to any @llvm.assume intrinsics.
-  for (auto &AssumeVH : AC.assumptions()) {
-    if (!AssumeVH)
-      continue;
-    auto *CI = cast<CallInst>(AssumeVH);
-    if (!DT.dominates(CI, Latch->getTerminator()))
-      continue;
-
-    if (isImpliedCond(Pred, LHS, RHS, CI->getArgOperand(0), false))
-      return true;
-  }
-
-  // If the loop is not reachable from the entry block, we risk running into an
-  // infinite loop as we walk up into the dom tree.  These loops do not matter
-  // anyway, so we just return a conservative answer when we see them.
-  if (!DT.isReachableFromEntry(L->getHeader()))
-    return false;
-
-  if (isImpliedViaGuard(Latch, Pred, LHS, RHS))
-    return true;
-
-  for (DomTreeNode *DTN = DT[Latch], *HeaderDTN = DT[L->getHeader()];
-       DTN != HeaderDTN; DTN = DTN->getIDom()) {
-    assert(DTN && "should reach the loop header before reaching the root!");
-
-    BasicBlock *BB = DTN->getBlock();
-    if (isImpliedViaGuard(BB, Pred, LHS, RHS))
-      return true;
-
-    BasicBlock *PBB = BB->getSinglePredecessor();
-    if (!PBB)
-      continue;
-
-    BranchInst *ContinuePredicate = dyn_cast<BranchInst>(PBB->getTerminator());
-    if (!ContinuePredicate || !ContinuePredicate->isConditional())
-      continue;
-
-    Value *Condition = ContinuePredicate->getCondition();
-
-    // If we have an edge `E` within the loop body that dominates the only
-    // latch, the condition guarding `E` also guards the backedge.  This
-    // reasoning works only for loops with a single latch.
-
-    BasicBlockEdge DominatingEdge(PBB, BB);
-    if (DominatingEdge.isSingleEdge()) {
-      // We're constructively (and conservatively) enumerating edges within the
-      // loop body that dominate the latch.  The dominator tree better agree
-      // with us on this:
-      assert(DT.dominates(DominatingEdge, Latch) && "should be!");
-
-      if (isImpliedCond(Pred, LHS, RHS, Condition,
-                        BB != ContinuePredicate->getSuccessor(0)))
-        return true;
-    }
-  }
-
-  return false;
-}
-
-bool
-ScalarEvolution::isLoopEntryGuardedByCond(const Loop *L,
-                                          ICmpInst::Predicate Pred,
-                                          const SCEV *LHS, const SCEV *RHS) {
-  // Interpret a null as meaning no loop, where there is obviously no guard
-  // (interprocedural conditions notwithstanding).
-  if (!L) return false;
-
-  if (VerifyIR)
-    assert(!verifyFunction(*L->getHeader()->getParent(), &dbgs()) &&
-           "This cannot be done on broken IR!");
-
-  // Both LHS and RHS must be available at loop entry.
-  assert(isAvailableAtLoopEntry(LHS, L) &&
-         "LHS is not available at Loop Entry");
-  assert(isAvailableAtLoopEntry(RHS, L) &&
-         "RHS is not available at Loop Entry");
-
-  if (isKnownViaNonRecursiveReasoning(Pred, LHS, RHS))
-    return true;
-
-  // If we cannot prove strict comparison (e.g. a > b), maybe we can prove
-  // the facts (a >= b && a != b) separately. A typical situation is when the
-  // non-strict comparison is known from ranges and non-equality is known from
-  // dominating predicates. If we are proving strict comparison, we always try
-  // to prove non-equality and non-strict comparison separately.
-  auto NonStrictPredicate = ICmpInst::getNonStrictPredicate(Pred);
-  const bool ProvingStrictComparison = (Pred != NonStrictPredicate);
-  bool ProvedNonStrictComparison = false;
-  bool ProvedNonEquality = false;
-
-  if (ProvingStrictComparison) {
-    ProvedNonStrictComparison =
-        isKnownViaNonRecursiveReasoning(NonStrictPredicate, LHS, RHS);
-    ProvedNonEquality =
-        isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_NE, LHS, RHS);
-    if (ProvedNonStrictComparison && ProvedNonEquality)
-      return true;
-  }
-
-  // Try to prove (Pred, LHS, RHS) using isImpliedViaGuard.
-  auto ProveViaGuard = [&](BasicBlock *Block) {
-    if (isImpliedViaGuard(Block, Pred, LHS, RHS))
-      return true;
-    if (ProvingStrictComparison) {
-      if (!ProvedNonStrictComparison)
-        ProvedNonStrictComparison =
-            isImpliedViaGuard(Block, NonStrictPredicate, LHS, RHS);
-      if (!ProvedNonEquality)
-        ProvedNonEquality =
-            isImpliedViaGuard(Block, ICmpInst::ICMP_NE, LHS, RHS);
-      if (ProvedNonStrictComparison && ProvedNonEquality)
-        return true;
-    }
-    return false;
-  };
-
-  // Try to prove (Pred, LHS, RHS) using isImpliedCond.
-  auto ProveViaCond = [&](Value *Condition, bool Inverse) {
-    if (isImpliedCond(Pred, LHS, RHS, Condition, Inverse))
-      return true;
-    if (ProvingStrictComparison) {
-      if (!ProvedNonStrictComparison)
-        ProvedNonStrictComparison =
-            isImpliedCond(NonStrictPredicate, LHS, RHS, Condition, Inverse);
-      if (!ProvedNonEquality)
-        ProvedNonEquality =
-            isImpliedCond(ICmpInst::ICMP_NE, LHS, RHS, Condition, Inverse);
-      if (ProvedNonStrictComparison && ProvedNonEquality)
-        return true;
-    }
-    return false;
-  };
-
-  // Starting at the loop predecessor, climb up the predecessor chain, as long
-  // as there are predecessors that can be found that have unique successors
-  // leading to the original header.
-  for (std::pair<BasicBlock *, BasicBlock *>
-         Pair(L->getLoopPredecessor(), L->getHeader());
-       Pair.first;
-       Pair = getPredecessorWithUniqueSuccessorForBB(Pair.first)) {
-
-    if (ProveViaGuard(Pair.first))
-      return true;
-
-    BranchInst *LoopEntryPredicate =
-      dyn_cast<BranchInst>(Pair.first->getTerminator());
-    if (!LoopEntryPredicate ||
-        LoopEntryPredicate->isUnconditional())
-      continue;
-
-    if (ProveViaCond(LoopEntryPredicate->getCondition(),
-                     LoopEntryPredicate->getSuccessor(0) != Pair.second))
-      return true;
-  }
-
-  // Check conditions due to any @llvm.assume intrinsics.
-  for (auto &AssumeVH : AC.assumptions()) {
-    if (!AssumeVH)
-      continue;
-    auto *CI = cast<CallInst>(AssumeVH);
-    if (!DT.dominates(CI, L->getHeader()))
-      continue;
-
-    if (ProveViaCond(CI->getArgOperand(0), false))
-      return true;
-  }
-
-  return false;
-}
-
-bool ScalarEvolution::isImpliedCond(ICmpInst::Predicate Pred,
-                                    const SCEV *LHS, const SCEV *RHS,
-                                    Value *FoundCondValue,
-                                    bool Inverse) {
-  if (!PendingLoopPredicates.insert(FoundCondValue).second)
-    return false;
-
-  auto ClearOnExit =
-      make_scope_exit([&]() { PendingLoopPredicates.erase(FoundCondValue); });
-
-  // Recursively handle And and Or conditions.
-  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(FoundCondValue)) {
-    if (BO->getOpcode() == Instruction::And) {
-      if (!Inverse)
-        return isImpliedCond(Pred, LHS, RHS, BO->getOperand(0), Inverse) ||
-               isImpliedCond(Pred, LHS, RHS, BO->getOperand(1), Inverse);
-    } else if (BO->getOpcode() == Instruction::Or) {
-      if (Inverse)
-        return isImpliedCond(Pred, LHS, RHS, BO->getOperand(0), Inverse) ||
-               isImpliedCond(Pred, LHS, RHS, BO->getOperand(1), Inverse);
-    }
-  }
-
-  ICmpInst *ICI = dyn_cast<ICmpInst>(FoundCondValue);
-  if (!ICI) return false;
-
-  // Now that we found a conditional branch that dominates the loop or controls
-  // the loop latch. Check to see if it is the comparison we are looking for.
-  ICmpInst::Predicate FoundPred;
-  if (Inverse)
-    FoundPred = ICI->getInversePredicate();
-  else
-    FoundPred = ICI->getPredicate();
-
-  const SCEV *FoundLHS = getSCEV(ICI->getOperand(0));
-  const SCEV *FoundRHS = getSCEV(ICI->getOperand(1));
-
-  return isImpliedCond(Pred, LHS, RHS, FoundPred, FoundLHS, FoundRHS);
-}
-
-bool ScalarEvolution::isImpliedCond(ICmpInst::Predicate Pred, const SCEV *LHS,
-                                    const SCEV *RHS,
-                                    ICmpInst::Predicate FoundPred,
-                                    const SCEV *FoundLHS,
-                                    const SCEV *FoundRHS) {
-  // Balance the types.
-  if (getTypeSizeInBits(LHS->getType()) <
-      getTypeSizeInBits(FoundLHS->getType())) {
-    if (CmpInst::isSigned(Pred)) {
-      LHS = getSignExtendExpr(LHS, FoundLHS->getType());
-      RHS = getSignExtendExpr(RHS, FoundLHS->getType());
-    } else {
-      LHS = getZeroExtendExpr(LHS, FoundLHS->getType());
-      RHS = getZeroExtendExpr(RHS, FoundLHS->getType());
-    }
-  } else if (getTypeSizeInBits(LHS->getType()) >
-      getTypeSizeInBits(FoundLHS->getType())) {
-    if (CmpInst::isSigned(FoundPred)) {
-      FoundLHS = getSignExtendExpr(FoundLHS, LHS->getType());
-      FoundRHS = getSignExtendExpr(FoundRHS, LHS->getType());
-    } else {
-      FoundLHS = getZeroExtendExpr(FoundLHS, LHS->getType());
-      FoundRHS = getZeroExtendExpr(FoundRHS, LHS->getType());
-    }
-  }
-
-  // Canonicalize the query to match the way instcombine will have
-  // canonicalized the comparison.
-  if (SimplifyICmpOperands(Pred, LHS, RHS))
-    if (LHS == RHS)
-      return CmpInst::isTrueWhenEqual(Pred);
-  if (SimplifyICmpOperands(FoundPred, FoundLHS, FoundRHS))
-    if (FoundLHS == FoundRHS)
-      return CmpInst::isFalseWhenEqual(FoundPred);
-
-  // Check to see if we can make the LHS or RHS match.
-  if (LHS == FoundRHS || RHS == FoundLHS) {
-    if (isa<SCEVConstant>(RHS)) {
-      std::swap(FoundLHS, FoundRHS);
-      FoundPred = ICmpInst::getSwappedPredicate(FoundPred);
-    } else {
-      std::swap(LHS, RHS);
-      Pred = ICmpInst::getSwappedPredicate(Pred);
-    }
-  }
-
-  // Check whether the found predicate is the same as the desired predicate.
-  if (FoundPred == Pred)
-    return isImpliedCondOperands(Pred, LHS, RHS, FoundLHS, FoundRHS);
-
-  // Check whether swapping the found predicate makes it the same as the
-  // desired predicate.
-  if (ICmpInst::getSwappedPredicate(FoundPred) == Pred) {
-    if (isa<SCEVConstant>(RHS))
-      return isImpliedCondOperands(Pred, LHS, RHS, FoundRHS, FoundLHS);
-    else
-      return isImpliedCondOperands(ICmpInst::getSwappedPredicate(Pred),
-                                   RHS, LHS, FoundLHS, FoundRHS);
-  }
-
-  // Unsigned comparison is the same as signed comparison when both the operands
-  // are non-negative.
-  if (CmpInst::isUnsigned(FoundPred) &&
-      CmpInst::getSignedPredicate(FoundPred) == Pred &&
-      isKnownNonNegative(FoundLHS) && isKnownNonNegative(FoundRHS))
-    return isImpliedCondOperands(Pred, LHS, RHS, FoundLHS, FoundRHS);
-
-  // Check if we can make progress by sharpening ranges.
-  if (FoundPred == ICmpInst::ICMP_NE &&
-      (isa<SCEVConstant>(FoundLHS) || isa<SCEVConstant>(FoundRHS))) {
-
-    const SCEVConstant *C = nullptr;
-    const SCEV *V = nullptr;
-
-    if (isa<SCEVConstant>(FoundLHS)) {
-      C = cast<SCEVConstant>(FoundLHS);
-      V = FoundRHS;
-    } else {
-      C = cast<SCEVConstant>(FoundRHS);
-      V = FoundLHS;
-    }
-
-    // The guarding predicate tells us that C != V. If the known range
-    // of V is [C, t), we can sharpen the range to [C + 1, t).  The
-    // range we consider has to correspond to same signedness as the
-    // predicate we're interested in folding.
-
-    APInt Min = ICmpInst::isSigned(Pred) ?
-        getSignedRangeMin(V) : getUnsignedRangeMin(V);
-
-    if (Min == C->getAPInt()) {
-      // Given (V >= Min && V != Min) we conclude V >= (Min + 1).
-      // This is true even if (Min + 1) wraps around -- in case of
-      // wraparound, (Min + 1) < Min, so (V >= Min => V >= (Min + 1)).
-
-      APInt SharperMin = Min + 1;
-
-      switch (Pred) {
-        case ICmpInst::ICMP_SGE:
-        case ICmpInst::ICMP_UGE:
-          // We know V `Pred` SharperMin.  If this implies LHS `Pred`
-          // RHS, we're done.
-          if (isImpliedCondOperands(Pred, LHS, RHS, V,
-                                    getConstant(SharperMin)))
-            return true;
-          LLVM_FALLTHROUGH;
-
-        case ICmpInst::ICMP_SGT:
-        case ICmpInst::ICMP_UGT:
-          // We know from the range information that (V `Pred` Min ||
-          // V == Min).  We know from the guarding condition that !(V
-          // == Min).  This gives us
-          //
-          //       V `Pred` Min || V == Min && !(V == Min)
-          //   =>  V `Pred` Min
-          //
-          // If V `Pred` Min implies LHS `Pred` RHS, we're done.
-
-          if (isImpliedCondOperands(Pred, LHS, RHS, V, getConstant(Min)))
-            return true;
-          LLVM_FALLTHROUGH;
-
-        default:
-          // No change
-          break;
-      }
-    }
-  }
-
-  // Check whether the actual condition is beyond sufficient.
-  if (FoundPred == ICmpInst::ICMP_EQ)
-    if (ICmpInst::isTrueWhenEqual(Pred))
-      if (isImpliedCondOperands(Pred, LHS, RHS, FoundLHS, FoundRHS))
-        return true;
-  if (Pred == ICmpInst::ICMP_NE)
-    if (!ICmpInst::isTrueWhenEqual(FoundPred))
-      if (isImpliedCondOperands(FoundPred, LHS, RHS, FoundLHS, FoundRHS))
-        return true;
-
-  // Otherwise assume the worst.
-  return false;
-}
-
-bool ScalarEvolution::splitBinaryAdd(const SCEV *Expr,
-                                     const SCEV *&L, const SCEV *&R,
-                                     SCEV::NoWrapFlags &Flags) {
-  const auto *AE = dyn_cast<SCEVAddExpr>(Expr);
-  if (!AE || AE->getNumOperands() != 2)
-    return false;
-
-  L = AE->getOperand(0);
-  R = AE->getOperand(1);
-  Flags = AE->getNoWrapFlags();
-  return true;
-}
-
-Optional<APInt> ScalarEvolution::computeConstantDifference(const SCEV *More,
-                                                           const SCEV *Less) {
-  // We avoid subtracting expressions here because this function is usually
-  // fairly deep in the call stack (i.e. is called many times).
-
-  if (isa<SCEVAddRecExpr>(Less) && isa<SCEVAddRecExpr>(More)) {
-    const auto *LAR = cast<SCEVAddRecExpr>(Less);
-    const auto *MAR = cast<SCEVAddRecExpr>(More);
-
-    if (LAR->getLoop() != MAR->getLoop())
-      return None;
-
-    // We look at affine expressions only; not for correctness but to keep
-    // getStepRecurrence cheap.
-    if (!LAR->isAffine() || !MAR->isAffine())
-      return None;
-
-    if (LAR->getStepRecurrence(*this) != MAR->getStepRecurrence(*this))
-      return None;
-
-    Less = LAR->getStart();
-    More = MAR->getStart();
-
-    // fall through
-  }
-
-  if (isa<SCEVConstant>(Less) && isa<SCEVConstant>(More)) {
-    const auto &M = cast<SCEVConstant>(More)->getAPInt();
-    const auto &L = cast<SCEVConstant>(Less)->getAPInt();
-    return M - L;
-  }
-
-  SCEV::NoWrapFlags Flags;
-  const SCEV *LLess = nullptr, *RLess = nullptr;
-  const SCEV *LMore = nullptr, *RMore = nullptr;
-  const SCEVConstant *C1 = nullptr, *C2 = nullptr;
-  // Compare (X + C1) vs X.
-  if (splitBinaryAdd(Less, LLess, RLess, Flags))
-    if ((C1 = dyn_cast<SCEVConstant>(LLess)))
-      if (RLess == More)
-        return -(C1->getAPInt());
-
-  // Compare X vs (X + C2).
-  if (splitBinaryAdd(More, LMore, RMore, Flags))
-    if ((C2 = dyn_cast<SCEVConstant>(LMore)))
-      if (RMore == Less)
-        return C2->getAPInt();
-
-  // Compare (X + C1) vs (X + C2).
-  if (C1 && C2 && RLess == RMore)
-    return C2->getAPInt() - C1->getAPInt();
-
-  return None;
-}
-
-bool ScalarEvolution::isImpliedCondOperandsViaNoOverflow(
-    ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS,
-    const SCEV *FoundLHS, const SCEV *FoundRHS) {
-  if (Pred != CmpInst::ICMP_SLT && Pred != CmpInst::ICMP_ULT)
-    return false;
-
-  const auto *AddRecLHS = dyn_cast<SCEVAddRecExpr>(LHS);
-  if (!AddRecLHS)
-    return false;
-
-  const auto *AddRecFoundLHS = dyn_cast<SCEVAddRecExpr>(FoundLHS);
-  if (!AddRecFoundLHS)
-    return false;
-
-  // We'd like to let SCEV reason about control dependencies, so we constrain
-  // both the inequalities to be about add recurrences on the same loop.  This
-  // way we can use isLoopEntryGuardedByCond later.
-
-  const Loop *L = AddRecFoundLHS->getLoop();
-  if (L != AddRecLHS->getLoop())
-    return false;
-
-  //  FoundLHS u< FoundRHS u< -C =>  (FoundLHS + C) u< (FoundRHS + C) ... (1)
-  //
-  //  FoundLHS s< FoundRHS s< INT_MIN - C => (FoundLHS + C) s< (FoundRHS + C)
-  //                                                                  ... (2)
-  //
-  // Informal proof for (2), assuming (1) [*]:
-  //
-  // We'll also assume (A s< B) <=> ((A + INT_MIN) u< (B + INT_MIN)) ... (3)[**]
-  //
-  // Then
-  //
-  //       FoundLHS s< FoundRHS s< INT_MIN - C
-  // <=>  (FoundLHS + INT_MIN) u< (FoundRHS + INT_MIN) u< -C   [ using (3) ]
-  // <=>  (FoundLHS + INT_MIN + C) u< (FoundRHS + INT_MIN + C) [ using (1) ]
-  // <=>  (FoundLHS + INT_MIN + C + INT_MIN) s<
-  //                        (FoundRHS + INT_MIN + C + INT_MIN) [ using (3) ]
-  // <=>  FoundLHS + C s< FoundRHS + C
-  //
-  // [*]: (1) can be proved by ruling out overflow.
-  //
-  // [**]: This can be proved by analyzing all the four possibilities:
-  //    (A s< 0, B s< 0), (A s< 0, B s>= 0), (A s>= 0, B s< 0) and
-  //    (A s>= 0, B s>= 0).
-  //
-  // Note:
-  // Despite (2), "FoundRHS s< INT_MIN - C" does not mean that "FoundRHS + C"
-  // will not sign underflow.  For instance, say FoundLHS = (i8 -128), FoundRHS
-  // = (i8 -127) and C = (i8 -100).  Then INT_MIN - C = (i8 -28), and FoundRHS
-  // s< (INT_MIN - C).  Lack of sign overflow / underflow in "FoundRHS + C" is
-  // neither necessary nor sufficient to prove "(FoundLHS + C) s< (FoundRHS +
-  // C)".
-
-  Optional<APInt> LDiff = computeConstantDifference(LHS, FoundLHS);
-  Optional<APInt> RDiff = computeConstantDifference(RHS, FoundRHS);
-  if (!LDiff || !RDiff || *LDiff != *RDiff)
-    return false;
-
-  if (LDiff->isMinValue())
-    return true;
-
-  APInt FoundRHSLimit;
-
-  if (Pred == CmpInst::ICMP_ULT) {
-    FoundRHSLimit = -(*RDiff);
-  } else {
-    assert(Pred == CmpInst::ICMP_SLT && "Checked above!");
-    FoundRHSLimit = APInt::getSignedMinValue(getTypeSizeInBits(RHS->getType())) - *RDiff;
-  }
-
-  // Try to prove (1) or (2), as needed.
-  return isAvailableAtLoopEntry(FoundRHS, L) &&
-         isLoopEntryGuardedByCond(L, Pred, FoundRHS,
-                                  getConstant(FoundRHSLimit));
-}
-
-bool ScalarEvolution::isImpliedViaMerge(ICmpInst::Predicate Pred,
-                                        const SCEV *LHS, const SCEV *RHS,
-                                        const SCEV *FoundLHS,
-                                        const SCEV *FoundRHS, unsigned Depth) {
-  const PHINode *LPhi = nullptr, *RPhi = nullptr;
-
-  auto ClearOnExit = make_scope_exit([&]() {
-    if (LPhi) {
-      bool Erased = PendingMerges.erase(LPhi);
-      assert(Erased && "Failed to erase LPhi!");
-      (void)Erased;
-    }
-    if (RPhi) {
-      bool Erased = PendingMerges.erase(RPhi);
-      assert(Erased && "Failed to erase RPhi!");
-      (void)Erased;
-    }
-  });
-
-  // Find respective Phis and check that they are not being pending.
-  if (const SCEVUnknown *LU = dyn_cast<SCEVUnknown>(LHS))
-    if (auto *Phi = dyn_cast<PHINode>(LU->getValue())) {
-      if (!PendingMerges.insert(Phi).second)
-        return false;
-      LPhi = Phi;
-    }
-  if (const SCEVUnknown *RU = dyn_cast<SCEVUnknown>(RHS))
-    if (auto *Phi = dyn_cast<PHINode>(RU->getValue())) {
-      // If we detect a loop of Phi nodes being processed by this method, for
-      // example:
-      //
-      //   %a = phi i32 [ %some1, %preheader ], [ %b, %latch ]
-      //   %b = phi i32 [ %some2, %preheader ], [ %a, %latch ]
-      //
-      // we don't want to deal with a case that complex, so return conservative
-      // answer false.
-      if (!PendingMerges.insert(Phi).second)
-        return false;
-      RPhi = Phi;
-    }
-
-  // If none of LHS, RHS is a Phi, nothing to do here.
-  if (!LPhi && !RPhi)
-    return false;
-
-  // If there is a SCEVUnknown Phi we are interested in, make it left.
-  if (!LPhi) {
-    std::swap(LHS, RHS);
-    std::swap(FoundLHS, FoundRHS);
-    std::swap(LPhi, RPhi);
-    Pred = ICmpInst::getSwappedPredicate(Pred);
-  }
-
-  assert(LPhi && "LPhi should definitely be a SCEVUnknown Phi!");
-  const BasicBlock *LBB = LPhi->getParent();
-  const SCEVAddRecExpr *RAR = dyn_cast<SCEVAddRecExpr>(RHS);
-
-  auto ProvedEasily = [&](const SCEV *S1, const SCEV *S2) {
-    return isKnownViaNonRecursiveReasoning(Pred, S1, S2) ||
-           isImpliedCondOperandsViaRanges(Pred, S1, S2, FoundLHS, FoundRHS) ||
-           isImpliedViaOperations(Pred, S1, S2, FoundLHS, FoundRHS, Depth);
-  };
-
-  if (RPhi && RPhi->getParent() == LBB) {
-    // Case one: RHS is also a SCEVUnknown Phi from the same basic block.
-    // If we compare two Phis from the same block, and for each entry block
-    // the predicate is true for incoming values from this block, then the
-    // predicate is also true for the Phis.
-    for (const BasicBlock *IncBB : predecessors(LBB)) {
-      const SCEV *L = getSCEV(LPhi->getIncomingValueForBlock(IncBB));
-      const SCEV *R = getSCEV(RPhi->getIncomingValueForBlock(IncBB));
-      if (!ProvedEasily(L, R))
-        return false;
-    }
-  } else if (RAR && RAR->getLoop()->getHeader() == LBB) {
-    // Case two: RHS is also a Phi from the same basic block, and it is an
-    // AddRec. It means that there is a loop which has both AddRec and Unknown
-    // PHIs, for it we can compare incoming values of AddRec from above the loop
-    // and latch with their respective incoming values of LPhi.
-    // TODO: Generalize to handle loops with many inputs in a header.
-    if (LPhi->getNumIncomingValues() != 2) return false;
-
-    auto *RLoop = RAR->getLoop();
-    auto *Predecessor = RLoop->getLoopPredecessor();
-    assert(Predecessor && "Loop with AddRec with no predecessor?");
-    const SCEV *L1 = getSCEV(LPhi->getIncomingValueForBlock(Predecessor));
-    if (!ProvedEasily(L1, RAR->getStart()))
-      return false;
-    auto *Latch = RLoop->getLoopLatch();
-    assert(Latch && "Loop with AddRec with no latch?");
-    const SCEV *L2 = getSCEV(LPhi->getIncomingValueForBlock(Latch));
-    if (!ProvedEasily(L2, RAR->getPostIncExpr(*this)))
-      return false;
-  } else {
-    // In all other cases go over inputs of LHS and compare each of them to RHS,
-    // the predicate is true for (LHS, RHS) if it is true for all such pairs.
-    // At this point RHS is either a non-Phi, or it is a Phi from some block
-    // different from LBB.
-    for (const BasicBlock *IncBB : predecessors(LBB)) {
-      // Check that RHS is available in this block.
-      if (!dominates(RHS, IncBB))
-        return false;
-      const SCEV *L = getSCEV(LPhi->getIncomingValueForBlock(IncBB));
-      if (!ProvedEasily(L, RHS))
-        return false;
-    }
-  }
-  return true;
-}
-
-bool ScalarEvolution::isImpliedCondOperands(ICmpInst::Predicate Pred,
-                                            const SCEV *LHS, const SCEV *RHS,
-                                            const SCEV *FoundLHS,
-                                            const SCEV *FoundRHS) {
-  if (isImpliedCondOperandsViaRanges(Pred, LHS, RHS, FoundLHS, FoundRHS))
-    return true;
-
-  if (isImpliedCondOperandsViaNoOverflow(Pred, LHS, RHS, FoundLHS, FoundRHS))
-    return true;
-
-  return isImpliedCondOperandsHelper(Pred, LHS, RHS,
-                                     FoundLHS, FoundRHS) ||
-         // ~x < ~y --> x > y
-         isImpliedCondOperandsHelper(Pred, LHS, RHS,
-                                     getNotSCEV(FoundRHS),
-                                     getNotSCEV(FoundLHS));
-}
-
-/// If Expr computes ~A, return A else return nullptr
-static const SCEV *MatchNotExpr(const SCEV *Expr) {
-  const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Expr);
-  if (!Add || Add->getNumOperands() != 2 ||
-      !Add->getOperand(0)->isAllOnesValue())
-    return nullptr;
-
-  const SCEVMulExpr *AddRHS = dyn_cast<SCEVMulExpr>(Add->getOperand(1));
-  if (!AddRHS || AddRHS->getNumOperands() != 2 ||
-      !AddRHS->getOperand(0)->isAllOnesValue())
-    return nullptr;
-
-  return AddRHS->getOperand(1);
-}
-
-/// Is MaybeMaxExpr an SMax or UMax of Candidate and some other values?
-template<typename MaxExprType>
-static bool IsMaxConsistingOf(const SCEV *MaybeMaxExpr,
-                              const SCEV *Candidate) {
-  const MaxExprType *MaxExpr = dyn_cast<MaxExprType>(MaybeMaxExpr);
-  if (!MaxExpr) return false;
-
-  return find(MaxExpr->operands(), Candidate) != MaxExpr->op_end();
-}
-
-/// Is MaybeMinExpr an SMin or UMin of Candidate and some other values?
-template<typename MaxExprType>
-static bool IsMinConsistingOf(ScalarEvolution &SE,
-                              const SCEV *MaybeMinExpr,
-                              const SCEV *Candidate) {
-  const SCEV *MaybeMaxExpr = MatchNotExpr(MaybeMinExpr);
-  if (!MaybeMaxExpr)
-    return false;
-
-  return IsMaxConsistingOf<MaxExprType>(MaybeMaxExpr, SE.getNotSCEV(Candidate));
-}
-
-static bool IsKnownPredicateViaAddRecStart(ScalarEvolution &SE,
-                                           ICmpInst::Predicate Pred,
-                                           const SCEV *LHS, const SCEV *RHS) {
-  // If both sides are affine addrecs for the same loop, with equal
-  // steps, and we know the recurrences don't wrap, then we only
-  // need to check the predicate on the starting values.
-
-  if (!ICmpInst::isRelational(Pred))
-    return false;
-
-  const SCEVAddRecExpr *LAR = dyn_cast<SCEVAddRecExpr>(LHS);
-  if (!LAR)
-    return false;
-  const SCEVAddRecExpr *RAR = dyn_cast<SCEVAddRecExpr>(RHS);
-  if (!RAR)
-    return false;
-  if (LAR->getLoop() != RAR->getLoop())
-    return false;
-  if (!LAR->isAffine() || !RAR->isAffine())
-    return false;
-
-  if (LAR->getStepRecurrence(SE) != RAR->getStepRecurrence(SE))
-    return false;
-
-  SCEV::NoWrapFlags NW = ICmpInst::isSigned(Pred) ?
-                         SCEV::FlagNSW : SCEV::FlagNUW;
-  if (!LAR->getNoWrapFlags(NW) || !RAR->getNoWrapFlags(NW))
-    return false;
-
-  return SE.isKnownPredicate(Pred, LAR->getStart(), RAR->getStart());
-}
-
-/// Is LHS `Pred` RHS true on the virtue of LHS or RHS being a Min or Max
-/// expression?
-static bool IsKnownPredicateViaMinOrMax(ScalarEvolution &SE,
-                                        ICmpInst::Predicate Pred,
-                                        const SCEV *LHS, const SCEV *RHS) {
-  switch (Pred) {
-  default:
-    return false;
-
-  case ICmpInst::ICMP_SGE:
-    std::swap(LHS, RHS);
-    LLVM_FALLTHROUGH;
-  case ICmpInst::ICMP_SLE:
-    return
-      // min(A, ...) <= A
-      IsMinConsistingOf<SCEVSMaxExpr>(SE, LHS, RHS) ||
-      // A <= max(A, ...)
-      IsMaxConsistingOf<SCEVSMaxExpr>(RHS, LHS);
-
-  case ICmpInst::ICMP_UGE:
-    std::swap(LHS, RHS);
-    LLVM_FALLTHROUGH;
-  case ICmpInst::ICMP_ULE:
-    return
-      // min(A, ...) <= A
-      IsMinConsistingOf<SCEVUMaxExpr>(SE, LHS, RHS) ||
-      // A <= max(A, ...)
-      IsMaxConsistingOf<SCEVUMaxExpr>(RHS, LHS);
-  }
-
-  llvm_unreachable("covered switch fell through?!");
-}
-
-bool ScalarEvolution::isImpliedViaOperations(ICmpInst::Predicate Pred,
-                                             const SCEV *LHS, const SCEV *RHS,
-                                             const SCEV *FoundLHS,
-                                             const SCEV *FoundRHS,
-                                             unsigned Depth) {
-  assert(getTypeSizeInBits(LHS->getType()) ==
-             getTypeSizeInBits(RHS->getType()) &&
-         "LHS and RHS have different sizes?");
-  assert(getTypeSizeInBits(FoundLHS->getType()) ==
-             getTypeSizeInBits(FoundRHS->getType()) &&
-         "FoundLHS and FoundRHS have different sizes?");
-  // We want to avoid hurting the compile time with analysis of too big trees.
-  if (Depth > MaxSCEVOperationsImplicationDepth)
-    return false;
-  // We only want to work with ICMP_SGT comparison so far.
-  // TODO: Extend to ICMP_UGT?
-  if (Pred == ICmpInst::ICMP_SLT) {
-    Pred = ICmpInst::ICMP_SGT;
-    std::swap(LHS, RHS);
-    std::swap(FoundLHS, FoundRHS);
-  }
-  if (Pred != ICmpInst::ICMP_SGT)
-    return false;
-
-  auto GetOpFromSExt = [&](const SCEV *S) {
-    if (auto *Ext = dyn_cast<SCEVSignExtendExpr>(S))
-      return Ext->getOperand();
-    // TODO: If S is a SCEVConstant then you can cheaply "strip" the sext off
-    // the constant in some cases.
-    return S;
-  };
-
-  // Acquire values from extensions.
-  auto *OrigLHS = LHS;
-  auto *OrigFoundLHS = FoundLHS;
-  LHS = GetOpFromSExt(LHS);
-  FoundLHS = GetOpFromSExt(FoundLHS);
-
-  // Is the SGT predicate can be proved trivially or using the found context.
-  auto IsSGTViaContext = [&](const SCEV *S1, const SCEV *S2) {
-    return isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_SGT, S1, S2) ||
-           isImpliedViaOperations(ICmpInst::ICMP_SGT, S1, S2, OrigFoundLHS,
-                                  FoundRHS, Depth + 1);
-  };
-
-  if (auto *LHSAddExpr = dyn_cast<SCEVAddExpr>(LHS)) {
-    // We want to avoid creation of any new non-constant SCEV. Since we are
-    // going to compare the operands to RHS, we should be certain that we don't
-    // need any size extensions for this. So let's decline all cases when the
-    // sizes of types of LHS and RHS do not match.
-    // TODO: Maybe try to get RHS from sext to catch more cases?
-    if (getTypeSizeInBits(LHS->getType()) != getTypeSizeInBits(RHS->getType()))
-      return false;
-
-    // Should not overflow.
-    if (!LHSAddExpr->hasNoSignedWrap())
-      return false;
-
-    auto *LL = LHSAddExpr->getOperand(0);
-    auto *LR = LHSAddExpr->getOperand(1);
-    auto *MinusOne = getNegativeSCEV(getOne(RHS->getType()));
-
-    // Checks that S1 >= 0 && S2 > RHS, trivially or using the found context.
-    auto IsSumGreaterThanRHS = [&](const SCEV *S1, const SCEV *S2) {
-      return IsSGTViaContext(S1, MinusOne) && IsSGTViaContext(S2, RHS);
-    };
-    // Try to prove the following rule:
-    // (LHS = LL + LR) && (LL >= 0) && (LR > RHS) => (LHS > RHS).
-    // (LHS = LL + LR) && (LR >= 0) && (LL > RHS) => (LHS > RHS).
-    if (IsSumGreaterThanRHS(LL, LR) || IsSumGreaterThanRHS(LR, LL))
-      return true;
-  } else if (auto *LHSUnknownExpr = dyn_cast<SCEVUnknown>(LHS)) {
-    Value *LL, *LR;
-    // FIXME: Once we have SDiv implemented, we can get rid of this matching.
-
-    using namespace llvm::PatternMatch;
-
-    if (match(LHSUnknownExpr->getValue(), m_SDiv(m_Value(LL), m_Value(LR)))) {
-      // Rules for division.
-      // We are going to perform some comparisons with Denominator and its
-      // derivative expressions. In general case, creating a SCEV for it may
-      // lead to a complex analysis of the entire graph, and in particular it
-      // can request trip count recalculation for the same loop. This would
-      // cache as SCEVCouldNotCompute to avoid the infinite recursion. To avoid
-      // this, we only want to create SCEVs that are constants in this section.
-      // So we bail if Denominator is not a constant.
-      if (!isa<ConstantInt>(LR))
-        return false;
-
-      auto *Denominator = cast<SCEVConstant>(getSCEV(LR));
-
-      // We want to make sure that LHS = FoundLHS / Denominator. If it is so,
-      // then a SCEV for the numerator already exists and matches with FoundLHS.
-      auto *Numerator = getExistingSCEV(LL);
-      if (!Numerator || Numerator->getType() != FoundLHS->getType())
-        return false;
-
-      // Make sure that the numerator matches with FoundLHS and the denominator
-      // is positive.
-      if (!HasSameValue(Numerator, FoundLHS) || !isKnownPositive(Denominator))
-        return false;
-
-      auto *DTy = Denominator->getType();
-      auto *FRHSTy = FoundRHS->getType();
-      if (DTy->isPointerTy() != FRHSTy->isPointerTy())
-        // One of types is a pointer and another one is not. We cannot extend
-        // them properly to a wider type, so let us just reject this case.
-        // TODO: Usage of getEffectiveSCEVType for DTy, FRHSTy etc should help
-        // to avoid this check.
-        return false;
-
-      // Given that:
-      // FoundLHS > FoundRHS, LHS = FoundLHS / Denominator, Denominator > 0.
-      auto *WTy = getWiderType(DTy, FRHSTy);
-      auto *DenominatorExt = getNoopOrSignExtend(Denominator, WTy);
-      auto *FoundRHSExt = getNoopOrSignExtend(FoundRHS, WTy);
-
-      // Try to prove the following rule:
-      // (FoundRHS > Denominator - 2) && (RHS <= 0) => (LHS > RHS).
-      // For example, given that FoundLHS > 2. It means that FoundLHS is at
-      // least 3. If we divide it by Denominator < 4, we will have at least 1.
-      auto *DenomMinusTwo = getMinusSCEV(DenominatorExt, getConstant(WTy, 2));
-      if (isKnownNonPositive(RHS) &&
-          IsSGTViaContext(FoundRHSExt, DenomMinusTwo))
-        return true;
-
-      // Try to prove the following rule:
-      // (FoundRHS > -1 - Denominator) && (RHS < 0) => (LHS > RHS).
-      // For example, given that FoundLHS > -3. Then FoundLHS is at least -2.
-      // If we divide it by Denominator > 2, then:
-      // 1. If FoundLHS is negative, then the result is 0.
-      // 2. If FoundLHS is non-negative, then the result is non-negative.
-      // Anyways, the result is non-negative.
-      auto *MinusOne = getNegativeSCEV(getOne(WTy));
-      auto *NegDenomMinusOne = getMinusSCEV(MinusOne, DenominatorExt);
-      if (isKnownNegative(RHS) &&
-          IsSGTViaContext(FoundRHSExt, NegDenomMinusOne))
-        return true;
-    }
-  }
-
-  // If our expression contained SCEVUnknown Phis, and we split it down and now
-  // need to prove something for them, try to prove the predicate for every
-  // possible incoming values of those Phis.
-  if (isImpliedViaMerge(Pred, OrigLHS, RHS, OrigFoundLHS, FoundRHS, Depth + 1))
-    return true;
-
-  return false;
-}
-
-bool
-ScalarEvolution::isKnownViaNonRecursiveReasoning(ICmpInst::Predicate Pred,
-                                           const SCEV *LHS, const SCEV *RHS) {
-  return isKnownPredicateViaConstantRanges(Pred, LHS, RHS) ||
-         IsKnownPredicateViaMinOrMax(*this, Pred, LHS, RHS) ||
-         IsKnownPredicateViaAddRecStart(*this, Pred, LHS, RHS) ||
-         isKnownPredicateViaNoOverflow(Pred, LHS, RHS);
-}
-
-bool
-ScalarEvolution::isImpliedCondOperandsHelper(ICmpInst::Predicate Pred,
-                                             const SCEV *LHS, const SCEV *RHS,
-                                             const SCEV *FoundLHS,
-                                             const SCEV *FoundRHS) {
-  switch (Pred) {
-  default: llvm_unreachable("Unexpected ICmpInst::Predicate value!");
-  case ICmpInst::ICMP_EQ:
-  case ICmpInst::ICMP_NE:
-    if (HasSameValue(LHS, FoundLHS) && HasSameValue(RHS, FoundRHS))
-      return true;
-    break;
-  case ICmpInst::ICMP_SLT:
-  case ICmpInst::ICMP_SLE:
-    if (isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_SLE, LHS, FoundLHS) &&
-        isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_SGE, RHS, FoundRHS))
-      return true;
-    break;
-  case ICmpInst::ICMP_SGT:
-  case ICmpInst::ICMP_SGE:
-    if (isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_SGE, LHS, FoundLHS) &&
-        isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_SLE, RHS, FoundRHS))
-      return true;
-    break;
-  case ICmpInst::ICMP_ULT:
-  case ICmpInst::ICMP_ULE:
-    if (isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_ULE, LHS, FoundLHS) &&
-        isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_UGE, RHS, FoundRHS))
-      return true;
-    break;
-  case ICmpInst::ICMP_UGT:
-  case ICmpInst::ICMP_UGE:
-    if (isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_UGE, LHS, FoundLHS) &&
-        isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_ULE, RHS, FoundRHS))
-      return true;
-    break;
-  }
-
-  // Maybe it can be proved via operations?
-  if (isImpliedViaOperations(Pred, LHS, RHS, FoundLHS, FoundRHS))
-    return true;
-
-  return false;
-}
-
-bool ScalarEvolution::isImpliedCondOperandsViaRanges(ICmpInst::Predicate Pred,
-                                                     const SCEV *LHS,
-                                                     const SCEV *RHS,
-                                                     const SCEV *FoundLHS,
-                                                     const SCEV *FoundRHS) {
-  if (!isa<SCEVConstant>(RHS) || !isa<SCEVConstant>(FoundRHS))
-    // The restriction on `FoundRHS` be lifted easily -- it exists only to
-    // reduce the compile time impact of this optimization.
-    return false;
-
-  Optional<APInt> Addend = computeConstantDifference(LHS, FoundLHS);
-  if (!Addend)
-    return false;
-
-  const APInt &ConstFoundRHS = cast<SCEVConstant>(FoundRHS)->getAPInt();
-
-  // `FoundLHSRange` is the range we know `FoundLHS` to be in by virtue of the
-  // antecedent "`FoundLHS` `Pred` `FoundRHS`".
-  ConstantRange FoundLHSRange =
-      ConstantRange::makeAllowedICmpRegion(Pred, ConstFoundRHS);
-
-  // Since `LHS` is `FoundLHS` + `Addend`, we can compute a range for `LHS`:
-  ConstantRange LHSRange = FoundLHSRange.add(ConstantRange(*Addend));
-
-  // We can also compute the range of values for `LHS` that satisfy the
-  // consequent, "`LHS` `Pred` `RHS`":
-  const APInt &ConstRHS = cast<SCEVConstant>(RHS)->getAPInt();
-  ConstantRange SatisfyingLHSRange =
-      ConstantRange::makeSatisfyingICmpRegion(Pred, ConstRHS);
-
-  // The antecedent implies the consequent if every value of `LHS` that
-  // satisfies the antecedent also satisfies the consequent.
-  return SatisfyingLHSRange.contains(LHSRange);
-}
-
-bool ScalarEvolution::doesIVOverflowOnLT(const SCEV *RHS, const SCEV *Stride,
-                                         bool IsSigned, bool NoWrap) {
-  assert(isKnownPositive(Stride) && "Positive stride expected!");
-
-  if (NoWrap) return false;
-
-  unsigned BitWidth = getTypeSizeInBits(RHS->getType());
-  const SCEV *One = getOne(Stride->getType());
-
-  if (IsSigned) {
-    APInt MaxRHS = getSignedRangeMax(RHS);
-    APInt MaxValue = APInt::getSignedMaxValue(BitWidth);
-    APInt MaxStrideMinusOne = getSignedRangeMax(getMinusSCEV(Stride, One));
-
-    // SMaxRHS + SMaxStrideMinusOne > SMaxValue => overflow!
-    return (std::move(MaxValue) - MaxStrideMinusOne).slt(MaxRHS);
-  }
-
-  APInt MaxRHS = getUnsignedRangeMax(RHS);
-  APInt MaxValue = APInt::getMaxValue(BitWidth);
-  APInt MaxStrideMinusOne = getUnsignedRangeMax(getMinusSCEV(Stride, One));
-
-  // UMaxRHS + UMaxStrideMinusOne > UMaxValue => overflow!
-  return (std::move(MaxValue) - MaxStrideMinusOne).ult(MaxRHS);
-}
-
-bool ScalarEvolution::doesIVOverflowOnGT(const SCEV *RHS, const SCEV *Stride,
-                                         bool IsSigned, bool NoWrap) {
-  if (NoWrap) return false;
-
-  unsigned BitWidth = getTypeSizeInBits(RHS->getType());
-  const SCEV *One = getOne(Stride->getType());
-
-  if (IsSigned) {
-    APInt MinRHS = getSignedRangeMin(RHS);
-    APInt MinValue = APInt::getSignedMinValue(BitWidth);
-    APInt MaxStrideMinusOne = getSignedRangeMax(getMinusSCEV(Stride, One));
-
-    // SMinRHS - SMaxStrideMinusOne < SMinValue => overflow!
-    return (std::move(MinValue) + MaxStrideMinusOne).sgt(MinRHS);
-  }
-
-  APInt MinRHS = getUnsignedRangeMin(RHS);
-  APInt MinValue = APInt::getMinValue(BitWidth);
-  APInt MaxStrideMinusOne = getUnsignedRangeMax(getMinusSCEV(Stride, One));
-
-  // UMinRHS - UMaxStrideMinusOne < UMinValue => overflow!
-  return (std::move(MinValue) + MaxStrideMinusOne).ugt(MinRHS);
-}
-
-const SCEV *ScalarEvolution::computeBECount(const SCEV *Delta, const SCEV *Step,
-                                            bool Equality) {
-  const SCEV *One = getOne(Step->getType());
-  Delta = Equality ? getAddExpr(Delta, Step)
-                   : getAddExpr(Delta, getMinusSCEV(Step, One));
-  return getUDivExpr(Delta, Step);
-}
-
-const SCEV *ScalarEvolution::computeMaxBECountForLT(const SCEV *Start,
-                                                    const SCEV *Stride,
-                                                    const SCEV *End,
-                                                    unsigned BitWidth,
-                                                    bool IsSigned) {
-
-  assert(!isKnownNonPositive(Stride) &&
-         "Stride is expected strictly positive!");
-  // Calculate the maximum backedge count based on the range of values
-  // permitted by Start, End, and Stride.
-  const SCEV *MaxBECount;
-  APInt MinStart =
-      IsSigned ? getSignedRangeMin(Start) : getUnsignedRangeMin(Start);
-
-  APInt StrideForMaxBECount =
-      IsSigned ? getSignedRangeMin(Stride) : getUnsignedRangeMin(Stride);
-
-  // We already know that the stride is positive, so we paper over conservatism
-  // in our range computation by forcing StrideForMaxBECount to be at least one.
-  // In theory this is unnecessary, but we expect MaxBECount to be a
-  // SCEVConstant, and (udiv <constant> 0) is not constant folded by SCEV (there
-  // is nothing to constant fold it to).
-  APInt One(BitWidth, 1, IsSigned);
-  StrideForMaxBECount = APIntOps::smax(One, StrideForMaxBECount);
-
-  APInt MaxValue = IsSigned ? APInt::getSignedMaxValue(BitWidth)
-                            : APInt::getMaxValue(BitWidth);
-  APInt Limit = MaxValue - (StrideForMaxBECount - 1);
-
-  // Although End can be a MAX expression we estimate MaxEnd considering only
-  // the case End = RHS of the loop termination condition. This is safe because
-  // in the other case (End - Start) is zero, leading to a zero maximum backedge
-  // taken count.
-  APInt MaxEnd = IsSigned ? APIntOps::smin(getSignedRangeMax(End), Limit)
-                          : APIntOps::umin(getUnsignedRangeMax(End), Limit);
-
-  MaxBECount = computeBECount(getConstant(MaxEnd - MinStart) /* Delta */,
-                              getConstant(StrideForMaxBECount) /* Step */,
-                              false /* Equality */);
-
-  return MaxBECount;
-}
-
-ScalarEvolution::ExitLimit
-ScalarEvolution::howManyLessThans(const SCEV *LHS, const SCEV *RHS,
-                                  const Loop *L, bool IsSigned,
-                                  bool ControlsExit, bool AllowPredicates) {
-  SmallPtrSet<const SCEVPredicate *, 4> Predicates;
-
-  const SCEVAddRecExpr *IV = dyn_cast<SCEVAddRecExpr>(LHS);
-  bool PredicatedIV = false;
-
-  if (!IV && AllowPredicates) {
-    // Try to make this an AddRec using runtime tests, in the first X
-    // iterations of this loop, where X is the SCEV expression found by the
-    // algorithm below.
-    IV = convertSCEVToAddRecWithPredicates(LHS, L, Predicates);
-    PredicatedIV = true;
-  }
-
-  // Avoid weird loops
-  if (!IV || IV->getLoop() != L || !IV->isAffine())
-    return getCouldNotCompute();
-
-  bool NoWrap = ControlsExit &&
-                IV->getNoWrapFlags(IsSigned ? SCEV::FlagNSW : SCEV::FlagNUW);
-
-  const SCEV *Stride = IV->getStepRecurrence(*this);
-
-  bool PositiveStride = isKnownPositive(Stride);
-
-  // Avoid negative or zero stride values.
-  if (!PositiveStride) {
-    // We can compute the correct backedge taken count for loops with unknown
-    // strides if we can prove that the loop is not an infinite loop with side
-    // effects. Here's the loop structure we are trying to handle -
-    //
-    // i = start
-    // do {
-    //   A[i] = i;
-    //   i += s;
-    // } while (i < end);
-    //
-    // The backedge taken count for such loops is evaluated as -
-    // (max(end, start + stride) - start - 1) /u stride
-    //
-    // The additional preconditions that we need to check to prove correctness
-    // of the above formula is as follows -
-    //
-    // a) IV is either nuw or nsw depending upon signedness (indicated by the
-    //    NoWrap flag).
-    // b) loop is single exit with no side effects.
-    //
-    //
-    // Precondition a) implies that if the stride is negative, this is a single
-    // trip loop. The backedge taken count formula reduces to zero in this case.
-    //
-    // Precondition b) implies that the unknown stride cannot be zero otherwise
-    // we have UB.
-    //
-    // The positive stride case is the same as isKnownPositive(Stride) returning
-    // true (original behavior of the function).
-    //
-    // We want to make sure that the stride is truly unknown as there are edge
-    // cases where ScalarEvolution propagates no wrap flags to the
-    // post-increment/decrement IV even though the increment/decrement operation
-    // itself is wrapping. The computed backedge taken count may be wrong in
-    // such cases. This is prevented by checking that the stride is not known to
-    // be either positive or non-positive. For example, no wrap flags are
-    // propagated to the post-increment IV of this loop with a trip count of 2 -
-    //
-    // unsigned char i;
-    // for(i=127; i<128; i+=129)
-    //   A[i] = i;
-    //
-    if (PredicatedIV || !NoWrap || isKnownNonPositive(Stride) ||
-        !loopHasNoSideEffects(L))
-      return getCouldNotCompute();
-  } else if (!Stride->isOne() &&
-             doesIVOverflowOnLT(RHS, Stride, IsSigned, NoWrap))
-    // Avoid proven overflow cases: this will ensure that the backedge taken
-    // count will not generate any unsigned overflow. Relaxed no-overflow
-    // conditions exploit NoWrapFlags, allowing to optimize in presence of
-    // undefined behaviors like the case of C language.
-    return getCouldNotCompute();
-
-  ICmpInst::Predicate Cond = IsSigned ? ICmpInst::ICMP_SLT
-                                      : ICmpInst::ICMP_ULT;
-  const SCEV *Start = IV->getStart();
-  const SCEV *End = RHS;
-  // When the RHS is not invariant, we do not know the end bound of the loop and
-  // cannot calculate the ExactBECount needed by ExitLimit. However, we can
-  // calculate the MaxBECount, given the start, stride and max value for the end
-  // bound of the loop (RHS), and the fact that IV does not overflow (which is
-  // checked above).
-  if (!isLoopInvariant(RHS, L)) {
-    const SCEV *MaxBECount = computeMaxBECountForLT(
-        Start, Stride, RHS, getTypeSizeInBits(LHS->getType()), IsSigned);
-    return ExitLimit(getCouldNotCompute() /* ExactNotTaken */, MaxBECount,
-                     false /*MaxOrZero*/, Predicates);
-  }
-  // If the backedge is taken at least once, then it will be taken
-  // (End-Start)/Stride times (rounded up to a multiple of Stride), where Start
-  // is the LHS value of the less-than comparison the first time it is evaluated
-  // and End is the RHS.
-  const SCEV *BECountIfBackedgeTaken =
-    computeBECount(getMinusSCEV(End, Start), Stride, false);
-  // If the loop entry is guarded by the result of the backedge test of the
-  // first loop iteration, then we know the backedge will be taken at least
-  // once and so the backedge taken count is as above. If not then we use the
-  // expression (max(End,Start)-Start)/Stride to describe the backedge count,
-  // as if the backedge is taken at least once max(End,Start) is End and so the
-  // result is as above, and if not max(End,Start) is Start so we get a backedge
-  // count of zero.
-  const SCEV *BECount;
-  if (isLoopEntryGuardedByCond(L, Cond, getMinusSCEV(Start, Stride), RHS))
-    BECount = BECountIfBackedgeTaken;
-  else {
-    End = IsSigned ? getSMaxExpr(RHS, Start) : getUMaxExpr(RHS, Start);
-    BECount = computeBECount(getMinusSCEV(End, Start), Stride, false);
-  }
-
-  const SCEV *MaxBECount;
-  bool MaxOrZero = false;
-  if (isa<SCEVConstant>(BECount))
-    MaxBECount = BECount;
-  else if (isa<SCEVConstant>(BECountIfBackedgeTaken)) {
-    // If we know exactly how many times the backedge will be taken if it's
-    // taken at least once, then the backedge count will either be that or
-    // zero.
-    MaxBECount = BECountIfBackedgeTaken;
-    MaxOrZero = true;
-  } else {
-    MaxBECount = computeMaxBECountForLT(
-        Start, Stride, RHS, getTypeSizeInBits(LHS->getType()), IsSigned);
-  }
-
-  if (isa<SCEVCouldNotCompute>(MaxBECount) &&
-      !isa<SCEVCouldNotCompute>(BECount))
-    MaxBECount = getConstant(getUnsignedRangeMax(BECount));
-
-  return ExitLimit(BECount, MaxBECount, MaxOrZero, Predicates);
-}
-
-ScalarEvolution::ExitLimit
-ScalarEvolution::howManyGreaterThans(const SCEV *LHS, const SCEV *RHS,
-                                     const Loop *L, bool IsSigned,
-                                     bool ControlsExit, bool AllowPredicates) {
-  SmallPtrSet<const SCEVPredicate *, 4> Predicates;
-  // We handle only IV > Invariant
-  if (!isLoopInvariant(RHS, L))
-    return getCouldNotCompute();
-
-  const SCEVAddRecExpr *IV = dyn_cast<SCEVAddRecExpr>(LHS);
-  if (!IV && AllowPredicates)
-    // Try to make this an AddRec using runtime tests, in the first X
-    // iterations of this loop, where X is the SCEV expression found by the
-    // algorithm below.
-    IV = convertSCEVToAddRecWithPredicates(LHS, L, Predicates);
-
-  // Avoid weird loops
-  if (!IV || IV->getLoop() != L || !IV->isAffine())
-    return getCouldNotCompute();
-
-  bool NoWrap = ControlsExit &&
-                IV->getNoWrapFlags(IsSigned ? SCEV::FlagNSW : SCEV::FlagNUW);
-
-  const SCEV *Stride = getNegativeSCEV(IV->getStepRecurrence(*this));
-
-  // Avoid negative or zero stride values
-  if (!isKnownPositive(Stride))
-    return getCouldNotCompute();
-
-  // Avoid proven overflow cases: this will ensure that the backedge taken count
-  // will not generate any unsigned overflow. Relaxed no-overflow conditions
-  // exploit NoWrapFlags, allowing to optimize in presence of undefined
-  // behaviors like the case of C language.
-  if (!Stride->isOne() && doesIVOverflowOnGT(RHS, Stride, IsSigned, NoWrap))
-    return getCouldNotCompute();
-
-  ICmpInst::Predicate Cond = IsSigned ? ICmpInst::ICMP_SGT
-                                      : ICmpInst::ICMP_UGT;
-
-  const SCEV *Start = IV->getStart();
-  const SCEV *End = RHS;
-  if (!isLoopEntryGuardedByCond(L, Cond, getAddExpr(Start, Stride), RHS))
-    End = IsSigned ? getSMinExpr(RHS, Start) : getUMinExpr(RHS, Start);
-
-  const SCEV *BECount = computeBECount(getMinusSCEV(Start, End), Stride, false);
-
-  APInt MaxStart = IsSigned ? getSignedRangeMax(Start)
-                            : getUnsignedRangeMax(Start);
-
-  APInt MinStride = IsSigned ? getSignedRangeMin(Stride)
-                             : getUnsignedRangeMin(Stride);
-
-  unsigned BitWidth = getTypeSizeInBits(LHS->getType());
-  APInt Limit = IsSigned ? APInt::getSignedMinValue(BitWidth) + (MinStride - 1)
-                         : APInt::getMinValue(BitWidth) + (MinStride - 1);
-
-  // Although End can be a MIN expression we estimate MinEnd considering only
-  // the case End = RHS. This is safe because in the other case (Start - End)
-  // is zero, leading to a zero maximum backedge taken count.
-  APInt MinEnd =
-    IsSigned ? APIntOps::smax(getSignedRangeMin(RHS), Limit)
-             : APIntOps::umax(getUnsignedRangeMin(RHS), Limit);
-
-
-  const SCEV *MaxBECount = getCouldNotCompute();
-  if (isa<SCEVConstant>(BECount))
-    MaxBECount = BECount;
-  else
-    MaxBECount = computeBECount(getConstant(MaxStart - MinEnd),
-                                getConstant(MinStride), false);
-
-  if (isa<SCEVCouldNotCompute>(MaxBECount))
-    MaxBECount = BECount;
-
-  return ExitLimit(BECount, MaxBECount, false, Predicates);
-}
-
-const SCEV *SCEVAddRecExpr::getNumIterationsInRange(const ConstantRange &Range,
-                                                    ScalarEvolution &SE) const {
-  if (Range.isFullSet())  // Infinite loop.
-    return SE.getCouldNotCompute();
-
-  // If the start is a non-zero constant, shift the range to simplify things.
-  if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(getStart()))
-    if (!SC->getValue()->isZero()) {
-      SmallVector<const SCEV *, 4> Operands(op_begin(), op_end());
-      Operands[0] = SE.getZero(SC->getType());
-      const SCEV *Shifted = SE.getAddRecExpr(Operands, getLoop(),
-                                             getNoWrapFlags(FlagNW));
-      if (const auto *ShiftedAddRec = dyn_cast<SCEVAddRecExpr>(Shifted))
-        return ShiftedAddRec->getNumIterationsInRange(
-            Range.subtract(SC->getAPInt()), SE);
-      // This is strange and shouldn't happen.
-      return SE.getCouldNotCompute();
-    }
-
-  // The only time we can solve this is when we have all constant indices.
-  // Otherwise, we cannot determine the overflow conditions.
-  if (any_of(operands(), [](const SCEV *Op) { return !isa<SCEVConstant>(Op); }))
-    return SE.getCouldNotCompute();
-
-  // Okay at this point we know that all elements of the chrec are constants and
-  // that the start element is zero.
-
-  // First check to see if the range contains zero.  If not, the first
-  // iteration exits.
-  unsigned BitWidth = SE.getTypeSizeInBits(getType());
-  if (!Range.contains(APInt(BitWidth, 0)))
-    return SE.getZero(getType());
-
-  if (isAffine()) {
-    // If this is an affine expression then we have this situation:
-    //   Solve {0,+,A} in Range  ===  Ax in Range
-
-    // We know that zero is in the range.  If A is positive then we know that
-    // the upper value of the range must be the first possible exit value.
-    // If A is negative then the lower of the range is the last possible loop
-    // value.  Also note that we already checked for a full range.
-    APInt A = cast<SCEVConstant>(getOperand(1))->getAPInt();
-    APInt End = A.sge(1) ? (Range.getUpper() - 1) : Range.getLower();
-
-    // The exit value should be (End+A)/A.
-    APInt ExitVal = (End + A).udiv(A);
-    ConstantInt *ExitValue = ConstantInt::get(SE.getContext(), ExitVal);
-
-    // Evaluate at the exit value.  If we really did fall out of the valid
-    // range, then we computed our trip count, otherwise wrap around or other
-    // things must have happened.
-    ConstantInt *Val = EvaluateConstantChrecAtConstant(this, ExitValue, SE);
-    if (Range.contains(Val->getValue()))
-      return SE.getCouldNotCompute();  // Something strange happened
-
-    // Ensure that the previous value is in the range.  This is a sanity check.
-    assert(Range.contains(
-           EvaluateConstantChrecAtConstant(this,
-           ConstantInt::get(SE.getContext(), ExitVal - 1), SE)->getValue()) &&
-           "Linear scev computation is off in a bad way!");
-    return SE.getConstant(ExitValue);
-  }
-
-  if (isQuadratic()) {
-    if (auto S = SolveQuadraticAddRecRange(this, Range, SE))
-      return SE.getConstant(S.getValue());
-  }
-
-  return SE.getCouldNotCompute();
-}
-
-const SCEVAddRecExpr *
-SCEVAddRecExpr::getPostIncExpr(ScalarEvolution &SE) const {
-  assert(getNumOperands() > 1 && "AddRec with zero step?");
-  // There is a temptation to just call getAddExpr(this, getStepRecurrence(SE)),
-  // but in this case we cannot guarantee that the value returned will be an
-  // AddRec because SCEV does not have a fixed point where it stops
-  // simplification: it is legal to return ({rec1} + {rec2}). For example, it
-  // may happen if we reach arithmetic depth limit while simplifying. So we
-  // construct the returned value explicitly.
-  SmallVector<const SCEV *, 3> Ops;
-  // If this is {A,+,B,+,C,...,+,N}, then its step is {B,+,C,+,...,+,N}, and
-  // (this + Step) is {A+B,+,B+C,+...,+,N}.
-  for (unsigned i = 0, e = getNumOperands() - 1; i < e; ++i)
-    Ops.push_back(SE.getAddExpr(getOperand(i), getOperand(i + 1)));
-  // We know that the last operand is not a constant zero (otherwise it would
-  // have been popped out earlier). This guarantees us that if the result has
-  // the same last operand, then it will also not be popped out, meaning that
-  // the returned value will be an AddRec.
-  const SCEV *Last = getOperand(getNumOperands() - 1);
-  assert(!Last->isZero() && "Recurrency with zero step?");
-  Ops.push_back(Last);
-  return cast<SCEVAddRecExpr>(SE.getAddRecExpr(Ops, getLoop(),
-                                               SCEV::FlagAnyWrap));
-}
-
-// Return true when S contains at least an undef value.
-static inline bool containsUndefs(const SCEV *S) {
-  return SCEVExprContains(S, [](const SCEV *S) {
-    if (const auto *SU = dyn_cast<SCEVUnknown>(S))
-      return isa<UndefValue>(SU->getValue());
-    else if (const auto *SC = dyn_cast<SCEVConstant>(S))
-      return isa<UndefValue>(SC->getValue());
-    return false;
-  });
-}
-
-namespace {
-
-// Collect all steps of SCEV expressions.
-struct SCEVCollectStrides {
-  ScalarEvolution &SE;
-  SmallVectorImpl<const SCEV *> &Strides;
-
-  SCEVCollectStrides(ScalarEvolution &SE, SmallVectorImpl<const SCEV *> &S)
-      : SE(SE), Strides(S) {}
-
-  bool follow(const SCEV *S) {
-    if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S))
-      Strides.push_back(AR->getStepRecurrence(SE));
-    return true;
-  }
-
-  bool isDone() const { return false; }
-};
-
-// Collect all SCEVUnknown and SCEVMulExpr expressions.
-struct SCEVCollectTerms {
-  SmallVectorImpl<const SCEV *> &Terms;
-
-  SCEVCollectTerms(SmallVectorImpl<const SCEV *> &T) : Terms(T) {}
-
-  bool follow(const SCEV *S) {
-    if (isa<SCEVUnknown>(S) || isa<SCEVMulExpr>(S) ||
-        isa<SCEVSignExtendExpr>(S)) {
-      if (!containsUndefs(S))
-        Terms.push_back(S);
-
-      // Stop recursion: once we collected a term, do not walk its operands.
-      return false;
-    }
-
-    // Keep looking.
-    return true;
-  }
-
-  bool isDone() const { return false; }
-};
-
-// Check if a SCEV contains an AddRecExpr.
-struct SCEVHasAddRec {
-  bool &ContainsAddRec;
-
-  SCEVHasAddRec(bool &ContainsAddRec) : ContainsAddRec(ContainsAddRec) {
-    ContainsAddRec = false;
-  }
-
-  bool follow(const SCEV *S) {
-    if (isa<SCEVAddRecExpr>(S)) {
-      ContainsAddRec = true;
-
-      // Stop recursion: once we collected a term, do not walk its operands.
-      return false;
-    }
-
-    // Keep looking.
-    return true;
-  }
-
-  bool isDone() const { return false; }
-};
-
-// Find factors that are multiplied with an expression that (possibly as a
-// subexpression) contains an AddRecExpr. In the expression:
-//
-//  8 * (100 +  %p * %q * (%a + {0, +, 1}_loop))
-//
-// "%p * %q" are factors multiplied by the expression "(%a + {0, +, 1}_loop)"
-// that contains the AddRec {0, +, 1}_loop. %p * %q are likely to be array size
-// parameters as they form a product with an induction variable.
-//
-// This collector expects all array size parameters to be in the same MulExpr.
-// It might be necessary to later add support for collecting parameters that are
-// spread over different nested MulExpr.
-struct SCEVCollectAddRecMultiplies {
-  SmallVectorImpl<const SCEV *> &Terms;
-  ScalarEvolution &SE;
-
-  SCEVCollectAddRecMultiplies(SmallVectorImpl<const SCEV *> &T, ScalarEvolution &SE)
-      : Terms(T), SE(SE) {}
-
-  bool follow(const SCEV *S) {
-    if (auto *Mul = dyn_cast<SCEVMulExpr>(S)) {
-      bool HasAddRec = false;
-      SmallVector<const SCEV *, 0> Operands;
-      for (auto Op : Mul->operands()) {
-        const SCEVUnknown *Unknown = dyn_cast<SCEVUnknown>(Op);
-        if (Unknown && !isa<CallInst>(Unknown->getValue())) {
-          Operands.push_back(Op);
-        } else if (Unknown) {
-          HasAddRec = true;
-        } else {
-          bool ContainsAddRec;
-          SCEVHasAddRec ContiansAddRec(ContainsAddRec);
-          visitAll(Op, ContiansAddRec);
-          HasAddRec |= ContainsAddRec;
-        }
-      }
-      if (Operands.size() == 0)
-        return true;
-
-      if (!HasAddRec)
-        return false;
-
-      Terms.push_back(SE.getMulExpr(Operands));
-      // Stop recursion: once we collected a term, do not walk its operands.
-      return false;
-    }
-
-    // Keep looking.
-    return true;
-  }
-
-  bool isDone() const { return false; }
-};
-
-} // end anonymous namespace
-
-/// Find parametric terms in this SCEVAddRecExpr. We first for parameters in
-/// two places:
-///   1) The strides of AddRec expressions.
-///   2) Unknowns that are multiplied with AddRec expressions.
-void ScalarEvolution::collectParametricTerms(const SCEV *Expr,
-    SmallVectorImpl<const SCEV *> &Terms) {
-  SmallVector<const SCEV *, 4> Strides;
-  SCEVCollectStrides StrideCollector(*this, Strides);
-  visitAll(Expr, StrideCollector);
-
-  LLVM_DEBUG({
-    dbgs() << "Strides:\n";
-    for (const SCEV *S : Strides)
-      dbgs() << *S << "\n";
-  });
-
-  for (const SCEV *S : Strides) {
-    SCEVCollectTerms TermCollector(Terms);
-    visitAll(S, TermCollector);
-  }
-
-  LLVM_DEBUG({
-    dbgs() << "Terms:\n";
-    for (const SCEV *T : Terms)
-      dbgs() << *T << "\n";
-  });
-
-  SCEVCollectAddRecMultiplies MulCollector(Terms, *this);
-  visitAll(Expr, MulCollector);
-}
-
-static bool findArrayDimensionsRec(ScalarEvolution &SE,
-                                   SmallVectorImpl<const SCEV *> &Terms,
-                                   SmallVectorImpl<const SCEV *> &Sizes) {
-  int Last = Terms.size() - 1;
-  const SCEV *Step = Terms[Last];
-
-  // End of recursion.
-  if (Last == 0) {
-    if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(Step)) {
-      SmallVector<const SCEV *, 2> Qs;
-      for (const SCEV *Op : M->operands())
-        if (!isa<SCEVConstant>(Op))
-          Qs.push_back(Op);
-
-      Step = SE.getMulExpr(Qs);
-    }
-
-    Sizes.push_back(Step);
-    return true;
-  }
-
-  for (const SCEV *&Term : Terms) {
-    // Normalize the terms before the next call to findArrayDimensionsRec.
-    const SCEV *Q, *R;
-    SCEVDivision::divide(SE, Term, Step, &Q, &R);
-
-    // Bail out when GCD does not evenly divide one of the terms.
-    if (!R->isZero())
-      return false;
-
-    Term = Q;
-  }
-
-  // Remove all SCEVConstants.
-  Terms.erase(
-      remove_if(Terms, [](const SCEV *E) { return isa<SCEVConstant>(E); }),
-      Terms.end());
-
-  if (Terms.size() > 0)
-    if (!findArrayDimensionsRec(SE, Terms, Sizes))
-      return false;
-
-  Sizes.push_back(Step);
-  return true;
-}
-
-// Returns true when one of the SCEVs of Terms contains a SCEVUnknown parameter.
-static inline bool containsParameters(SmallVectorImpl<const SCEV *> &Terms) {
-  for (const SCEV *T : Terms)
-    if (SCEVExprContains(T, isa<SCEVUnknown, const SCEV *>))
-      return true;
-  return false;
-}
-
-// Return the number of product terms in S.
-static inline int numberOfTerms(const SCEV *S) {
-  if (const SCEVMulExpr *Expr = dyn_cast<SCEVMulExpr>(S))
-    return Expr->getNumOperands();
-  return 1;
-}
-
-static const SCEV *removeConstantFactors(ScalarEvolution &SE, const SCEV *T) {
-  if (isa<SCEVConstant>(T))
-    return nullptr;
-
-  if (isa<SCEVUnknown>(T))
-    return T;
-
-  if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(T)) {
-    SmallVector<const SCEV *, 2> Factors;
-    for (const SCEV *Op : M->operands())
-      if (!isa<SCEVConstant>(Op))
-        Factors.push_back(Op);
-
-    return SE.getMulExpr(Factors);
-  }
-
-  return T;
-}
-
-/// Return the size of an element read or written by Inst.
-const SCEV *ScalarEvolution::getElementSize(Instruction *Inst) {
-  Type *Ty;
-  if (StoreInst *Store = dyn_cast<StoreInst>(Inst))
-    Ty = Store->getValueOperand()->getType();
-  else if (LoadInst *Load = dyn_cast<LoadInst>(Inst))
-    Ty = Load->getType();
-  else
-    return nullptr;
-
-  Type *ETy = getEffectiveSCEVType(PointerType::getUnqual(Ty));
-  return getSizeOfExpr(ETy, Ty);
-}
-
-void ScalarEvolution::findArrayDimensions(SmallVectorImpl<const SCEV *> &Terms,
-                                          SmallVectorImpl<const SCEV *> &Sizes,
-                                          const SCEV *ElementSize) {
-  if (Terms.size() < 1 || !ElementSize)
-    return;
-
-  // Early return when Terms do not contain parameters: we do not delinearize
-  // non parametric SCEVs.
-  if (!containsParameters(Terms))
-    return;
-
-  LLVM_DEBUG({
-    dbgs() << "Terms:\n";
-    for (const SCEV *T : Terms)
-      dbgs() << *T << "\n";
-  });
-
-  // Remove duplicates.
-  array_pod_sort(Terms.begin(), Terms.end());
-  Terms.erase(std::unique(Terms.begin(), Terms.end()), Terms.end());
-
-  // Put larger terms first.
-  llvm::sort(Terms, [](const SCEV *LHS, const SCEV *RHS) {
-    return numberOfTerms(LHS) > numberOfTerms(RHS);
-  });
-
-  // Try to divide all terms by the element size. If term is not divisible by
-  // element size, proceed with the original term.
-  for (const SCEV *&Term : Terms) {
-    const SCEV *Q, *R;
-    SCEVDivision::divide(*this, Term, ElementSize, &Q, &R);
-    if (!Q->isZero())
-      Term = Q;
-  }
-
-  SmallVector<const SCEV *, 4> NewTerms;
-
-  // Remove constant factors.
-  for (const SCEV *T : Terms)
-    if (const SCEV *NewT = removeConstantFactors(*this, T))
-      NewTerms.push_back(NewT);
-
-  LLVM_DEBUG({
-    dbgs() << "Terms after sorting:\n";
-    for (const SCEV *T : NewTerms)
-      dbgs() << *T << "\n";
-  });
-
-  if (NewTerms.empty() || !findArrayDimensionsRec(*this, NewTerms, Sizes)) {
-    Sizes.clear();
-    return;
-  }
-
-  // The last element to be pushed into Sizes is the size of an element.
-  Sizes.push_back(ElementSize);
-
-  LLVM_DEBUG({
-    dbgs() << "Sizes:\n";
-    for (const SCEV *S : Sizes)
-      dbgs() << *S << "\n";
-  });
-}
-
-void ScalarEvolution::computeAccessFunctions(
-    const SCEV *Expr, SmallVectorImpl<const SCEV *> &Subscripts,
-    SmallVectorImpl<const SCEV *> &Sizes) {
-  // Early exit in case this SCEV is not an affine multivariate function.
-  if (Sizes.empty())
-    return;
-
-  if (auto *AR = dyn_cast<SCEVAddRecExpr>(Expr))
-    if (!AR->isAffine())
-      return;
-
-  const SCEV *Res = Expr;
-  int Last = Sizes.size() - 1;
-  for (int i = Last; i >= 0; i--) {
-    const SCEV *Q, *R;
-    SCEVDivision::divide(*this, Res, Sizes[i], &Q, &R);
-
-    LLVM_DEBUG({
-      dbgs() << "Res: " << *Res << "\n";
-      dbgs() << "Sizes[i]: " << *Sizes[i] << "\n";
-      dbgs() << "Res divided by Sizes[i]:\n";
-      dbgs() << "Quotient: " << *Q << "\n";
-      dbgs() << "Remainder: " << *R << "\n";
-    });
-
-    Res = Q;
-
-    // Do not record the last subscript corresponding to the size of elements in
-    // the array.
-    if (i == Last) {
-
-      // Bail out if the remainder is too complex.
-      if (isa<SCEVAddRecExpr>(R)) {
-        Subscripts.clear();
-        Sizes.clear();
-        return;
-      }
-
-      continue;
-    }
-
-    // Record the access function for the current subscript.
-    Subscripts.push_back(R);
-  }
-
-  // Also push in last position the remainder of the last division: it will be
-  // the access function of the innermost dimension.
-  Subscripts.push_back(Res);
-
-  std::reverse(Subscripts.begin(), Subscripts.end());
-
-  LLVM_DEBUG({
-    dbgs() << "Subscripts:\n";
-    for (const SCEV *S : Subscripts)
-      dbgs() << *S << "\n";
-  });
-}
-
-/// Splits the SCEV into two vectors of SCEVs representing the subscripts and
-/// sizes of an array access. Returns the remainder of the delinearization that
-/// is the offset start of the array.  The SCEV->delinearize algorithm computes
-/// the multiples of SCEV coefficients: that is a pattern matching of sub
-/// expressions in the stride and base of a SCEV corresponding to the
-/// computation of a GCD (greatest common divisor) of base and stride.  When
-/// SCEV->delinearize fails, it returns the SCEV unchanged.
-///
-/// For example: when analyzing the memory access A[i][j][k] in this loop nest
-///
-///  void foo(long n, long m, long o, double A[n][m][o]) {
-///
-///    for (long i = 0; i < n; i++)
-///      for (long j = 0; j < m; j++)
-///        for (long k = 0; k < o; k++)
-///          A[i][j][k] = 1.0;
-///  }
-///
-/// the delinearization input is the following AddRec SCEV:
-///
-///  AddRec: {{{%A,+,(8 * %m * %o)}<%for.i>,+,(8 * %o)}<%for.j>,+,8}<%for.k>
-///
-/// From this SCEV, we are able to say that the base offset of the access is %A
-/// because it appears as an offset that does not divide any of the strides in
-/// the loops:
-///
-///  CHECK: Base offset: %A
-///
-/// and then SCEV->delinearize determines the size of some of the dimensions of
-/// the array as these are the multiples by which the strides are happening:
-///
-///  CHECK: ArrayDecl[UnknownSize][%m][%o] with elements of sizeof(double) bytes.
-///
-/// Note that the outermost dimension remains of UnknownSize because there are
-/// no strides that would help identifying the size of the last dimension: when
-/// the array has been statically allocated, one could compute the size of that
-/// dimension by dividing the overall size of the array by the size of the known
-/// dimensions: %m * %o * 8.
-///
-/// Finally delinearize provides the access functions for the array reference
-/// that does correspond to A[i][j][k] of the above C testcase:
-///
-///  CHECK: ArrayRef[{0,+,1}<%for.i>][{0,+,1}<%for.j>][{0,+,1}<%for.k>]
-///
-/// The testcases are checking the output of a function pass:
-/// DelinearizationPass that walks through all loads and stores of a function
-/// asking for the SCEV of the memory access with respect to all enclosing
-/// loops, calling SCEV->delinearize on that and printing the results.
-void ScalarEvolution::delinearize(const SCEV *Expr,
-                                 SmallVectorImpl<const SCEV *> &Subscripts,
-                                 SmallVectorImpl<const SCEV *> &Sizes,
-                                 const SCEV *ElementSize) {
-  // First step: collect parametric terms.
-  SmallVector<const SCEV *, 4> Terms;
-  collectParametricTerms(Expr, Terms);
-
-  if (Terms.empty())
-    return;
-
-  // Second step: find subscript sizes.
-  findArrayDimensions(Terms, Sizes, ElementSize);
-
-  if (Sizes.empty())
-    return;
-
-  // Third step: compute the access functions for each subscript.
-  computeAccessFunctions(Expr, Subscripts, Sizes);
-
-  if (Subscripts.empty())
-    return;
-
-  LLVM_DEBUG({
-    dbgs() << "succeeded to delinearize " << *Expr << "\n";
-    dbgs() << "ArrayDecl[UnknownSize]";
-    for (const SCEV *S : Sizes)
-      dbgs() << "[" << *S << "]";
-
-    dbgs() << "\nArrayRef";
-    for (const SCEV *S : Subscripts)
-      dbgs() << "[" << *S << "]";
-    dbgs() << "\n";
-  });
-}
-
-//===----------------------------------------------------------------------===//
-//                   SCEVCallbackVH Class Implementation
-//===----------------------------------------------------------------------===//
-
-void ScalarEvolution::SCEVCallbackVH::deleted() {
-  assert(SE && "SCEVCallbackVH called with a null ScalarEvolution!");
-  if (PHINode *PN = dyn_cast<PHINode>(getValPtr()))
-    SE->ConstantEvolutionLoopExitValue.erase(PN);
-  SE->eraseValueFromMap(getValPtr());
-  // this now dangles!
-}
-
-void ScalarEvolution::SCEVCallbackVH::allUsesReplacedWith(Value *V) {
-  assert(SE && "SCEVCallbackVH called with a null ScalarEvolution!");
-
-  // Forget all the expressions associated with users of the old value,
-  // so that future queries will recompute the expressions using the new
-  // value.
-  Value *Old = getValPtr();
-  SmallVector<User *, 16> Worklist(Old->user_begin(), Old->user_end());
-  SmallPtrSet<User *, 8> Visited;
-  while (!Worklist.empty()) {
-    User *U = Worklist.pop_back_val();
-    // Deleting the Old value will cause this to dangle. Postpone
-    // that until everything else is done.
-    if (U == Old)
-      continue;
-    if (!Visited.insert(U).second)
-      continue;
-    if (PHINode *PN = dyn_cast<PHINode>(U))
-      SE->ConstantEvolutionLoopExitValue.erase(PN);
-    SE->eraseValueFromMap(U);
-    Worklist.insert(Worklist.end(), U->user_begin(), U->user_end());
-  }
-  // Delete the Old value.
-  if (PHINode *PN = dyn_cast<PHINode>(Old))
-    SE->ConstantEvolutionLoopExitValue.erase(PN);
-  SE->eraseValueFromMap(Old);
-  // this now dangles!
-}
-
-ScalarEvolution::SCEVCallbackVH::SCEVCallbackVH(Value *V, ScalarEvolution *se)
-  : CallbackVH(V), SE(se) {}
-
-//===----------------------------------------------------------------------===//
-//                   ScalarEvolution Class Implementation
-//===----------------------------------------------------------------------===//
-
-ScalarEvolution::ScalarEvolution(Function &F, TargetLibraryInfo &TLI,
-                                 AssumptionCache &AC, DominatorTree &DT,
-                                 LoopInfo &LI)
-    : F(F), TLI(TLI), AC(AC), DT(DT), LI(LI),
-      CouldNotCompute(new SCEVCouldNotCompute()), ValuesAtScopes(64),
-      LoopDispositions(64), BlockDispositions(64) {
-  // To use guards for proving predicates, we need to scan every instruction in
-  // relevant basic blocks, and not just terminators.  Doing this is a waste of
-  // time if the IR does not actually contain any calls to
-  // @llvm.experimental.guard, so do a quick check and remember this beforehand.
-  //
-  // This pessimizes the case where a pass that preserves ScalarEvolution wants
-  // to _add_ guards to the module when there weren't any before, and wants
-  // ScalarEvolution to optimize based on those guards.  For now we prefer to be
-  // efficient in lieu of being smart in that rather obscure case.
-
-  auto *GuardDecl = F.getParent()->getFunction(
-      Intrinsic::getName(Intrinsic::experimental_guard));
-  HasGuards = GuardDecl && !GuardDecl->use_empty();
-}
-
-ScalarEvolution::ScalarEvolution(ScalarEvolution &&Arg)
-    : F(Arg.F), HasGuards(Arg.HasGuards), TLI(Arg.TLI), AC(Arg.AC), DT(Arg.DT),
-      LI(Arg.LI), CouldNotCompute(std::move(Arg.CouldNotCompute)),
-      ValueExprMap(std::move(Arg.ValueExprMap)),
-      PendingLoopPredicates(std::move(Arg.PendingLoopPredicates)),
-      PendingPhiRanges(std::move(Arg.PendingPhiRanges)),
-      PendingMerges(std::move(Arg.PendingMerges)),
-      MinTrailingZerosCache(std::move(Arg.MinTrailingZerosCache)),
-      BackedgeTakenCounts(std::move(Arg.BackedgeTakenCounts)),
-      PredicatedBackedgeTakenCounts(
-          std::move(Arg.PredicatedBackedgeTakenCounts)),
-      ConstantEvolutionLoopExitValue(
-          std::move(Arg.ConstantEvolutionLoopExitValue)),
-      ValuesAtScopes(std::move(Arg.ValuesAtScopes)),
-      LoopDispositions(std::move(Arg.LoopDispositions)),
-      LoopPropertiesCache(std::move(Arg.LoopPropertiesCache)),
-      BlockDispositions(std::move(Arg.BlockDispositions)),
-      UnsignedRanges(std::move(Arg.UnsignedRanges)),
-      SignedRanges(std::move(Arg.SignedRanges)),
-      UniqueSCEVs(std::move(Arg.UniqueSCEVs)),
-      UniquePreds(std::move(Arg.UniquePreds)),
-      SCEVAllocator(std::move(Arg.SCEVAllocator)),
-      LoopUsers(std::move(Arg.LoopUsers)),
-      PredicatedSCEVRewrites(std::move(Arg.PredicatedSCEVRewrites)),
-      FirstUnknown(Arg.FirstUnknown) {
-  Arg.FirstUnknown = nullptr;
-}
-
-ScalarEvolution::~ScalarEvolution() {
-  // Iterate through all the SCEVUnknown instances and call their
-  // destructors, so that they release their references to their values.
-  for (SCEVUnknown *U = FirstUnknown; U;) {
-    SCEVUnknown *Tmp = U;
-    U = U->Next;
-    Tmp->~SCEVUnknown();
-  }
-  FirstUnknown = nullptr;
-
-  ExprValueMap.clear();
-  ValueExprMap.clear();
-  HasRecMap.clear();
-
-  // Free any extra memory created for ExitNotTakenInfo in the unlikely event
-  // that a loop had multiple computable exits.
-  for (auto &BTCI : BackedgeTakenCounts)
-    BTCI.second.clear();
-  for (auto &BTCI : PredicatedBackedgeTakenCounts)
-    BTCI.second.clear();
-
-  assert(PendingLoopPredicates.empty() && "isImpliedCond garbage");
-  assert(PendingPhiRanges.empty() && "getRangeRef garbage");
-  assert(PendingMerges.empty() && "isImpliedViaMerge garbage");
-  assert(!WalkingBEDominatingConds && "isLoopBackedgeGuardedByCond garbage!");
-  assert(!ProvingSplitPredicate && "ProvingSplitPredicate garbage!");
-}
-
-bool ScalarEvolution::hasLoopInvariantBackedgeTakenCount(const Loop *L) {
-  return !isa<SCEVCouldNotCompute>(getBackedgeTakenCount(L));
-}
-
-static void PrintLoopInfo(raw_ostream &OS, ScalarEvolution *SE,
-                          const Loop *L) {
-  // Print all inner loops first
-  for (Loop *I : *L)
-    PrintLoopInfo(OS, SE, I);
-
-  OS << "Loop ";
-  L->getHeader()->printAsOperand(OS, /*PrintType=*/false);
-  OS << ": ";
-
-  SmallVector<BasicBlock *, 8> ExitBlocks;
-  L->getExitBlocks(ExitBlocks);
-  if (ExitBlocks.size() != 1)
-    OS << "<multiple exits> ";
-
-  if (SE->hasLoopInvariantBackedgeTakenCount(L)) {
-    OS << "backedge-taken count is " << *SE->getBackedgeTakenCount(L);
-  } else {
-    OS << "Unpredictable backedge-taken count. ";
-  }
-
-  OS << "\n"
-        "Loop ";
-  L->getHeader()->printAsOperand(OS, /*PrintType=*/false);
-  OS << ": ";
-
-  if (!isa<SCEVCouldNotCompute>(SE->getMaxBackedgeTakenCount(L))) {
-    OS << "max backedge-taken count is " << *SE->getMaxBackedgeTakenCount(L);
-    if (SE->isBackedgeTakenCountMaxOrZero(L))
-      OS << ", actual taken count either this or zero.";
-  } else {
-    OS << "Unpredictable max backedge-taken count. ";
-  }
-
-  OS << "\n"
-        "Loop ";
-  L->getHeader()->printAsOperand(OS, /*PrintType=*/false);
-  OS << ": ";
-
-  SCEVUnionPredicate Pred;
-  auto PBT = SE->getPredicatedBackedgeTakenCount(L, Pred);
-  if (!isa<SCEVCouldNotCompute>(PBT)) {
-    OS << "Predicated backedge-taken count is " << *PBT << "\n";
-    OS << " Predicates:\n";
-    Pred.print(OS, 4);
-  } else {
-    OS << "Unpredictable predicated backedge-taken count. ";
-  }
-  OS << "\n";
-
-  if (SE->hasLoopInvariantBackedgeTakenCount(L)) {
-    OS << "Loop ";
-    L->getHeader()->printAsOperand(OS, /*PrintType=*/false);
-    OS << ": ";
-    OS << "Trip multiple is " << SE->getSmallConstantTripMultiple(L) << "\n";
-  }
-}
-
-static StringRef loopDispositionToStr(ScalarEvolution::LoopDisposition LD) {
-  switch (LD) {
-  case ScalarEvolution::LoopVariant:
-    return "Variant";
-  case ScalarEvolution::LoopInvariant:
-    return "Invariant";
-  case ScalarEvolution::LoopComputable:
-    return "Computable";
-  }
-  llvm_unreachable("Unknown ScalarEvolution::LoopDisposition kind!");
-}
-
-void ScalarEvolution::print(raw_ostream &OS) const {
-  // ScalarEvolution's implementation of the print method is to print
-  // out SCEV values of all instructions that are interesting. Doing
-  // this potentially causes it to create new SCEV objects though,
-  // which technically conflicts with the const qualifier. This isn't
-  // observable from outside the class though, so casting away the
-  // const isn't dangerous.
-  ScalarEvolution &SE = *const_cast<ScalarEvolution *>(this);
-
-  OS << "Classifying expressions for: ";
-  F.printAsOperand(OS, /*PrintType=*/false);
-  OS << "\n";
-  for (Instruction &I : instructions(F))
-    if (isSCEVable(I.getType()) && !isa<CmpInst>(I)) {
-      OS << I << '\n';
-      OS << "  -->  ";
-      const SCEV *SV = SE.getSCEV(&I);
-      SV->print(OS);
-      if (!isa<SCEVCouldNotCompute>(SV)) {
-        OS << " U: ";
-        SE.getUnsignedRange(SV).print(OS);
-        OS << " S: ";
-        SE.getSignedRange(SV).print(OS);
-      }
-
-      const Loop *L = LI.getLoopFor(I.getParent());
-
-      const SCEV *AtUse = SE.getSCEVAtScope(SV, L);
-      if (AtUse != SV) {
-        OS << "  -->  ";
-        AtUse->print(OS);
-        if (!isa<SCEVCouldNotCompute>(AtUse)) {
-          OS << " U: ";
-          SE.getUnsignedRange(AtUse).print(OS);
-          OS << " S: ";
-          SE.getSignedRange(AtUse).print(OS);
-        }
-      }
-
-      if (L) {
-        OS << "\t\t" "Exits: ";
-        const SCEV *ExitValue = SE.getSCEVAtScope(SV, L->getParentLoop());
-        if (!SE.isLoopInvariant(ExitValue, L)) {
-          OS << "<<Unknown>>";
-        } else {
-          OS << *ExitValue;
-        }
-
-        bool First = true;
-        for (auto *Iter = L; Iter; Iter = Iter->getParentLoop()) {
-          if (First) {
-            OS << "\t\t" "LoopDispositions: { ";
-            First = false;
-          } else {
-            OS << ", ";
-          }
-
-          Iter->getHeader()->printAsOperand(OS, /*PrintType=*/false);
-          OS << ": " << loopDispositionToStr(SE.getLoopDisposition(SV, Iter));
-        }
-
-        for (auto *InnerL : depth_first(L)) {
-          if (InnerL == L)
-            continue;
-          if (First) {
-            OS << "\t\t" "LoopDispositions: { ";
-            First = false;
-          } else {
-            OS << ", ";
-          }
-
-          InnerL->getHeader()->printAsOperand(OS, /*PrintType=*/false);
-          OS << ": " << loopDispositionToStr(SE.getLoopDisposition(SV, InnerL));
-        }
-
-        OS << " }";
-      }
-
-      OS << "\n";
-    }
-
-  OS << "Determining loop execution counts for: ";
-  F.printAsOperand(OS, /*PrintType=*/false);
-  OS << "\n";
-  for (Loop *I : LI)
-    PrintLoopInfo(OS, &SE, I);
-}
-
-ScalarEvolution::LoopDisposition
-ScalarEvolution::getLoopDisposition(const SCEV *S, const Loop *L) {
-  auto &Values = LoopDispositions[S];
-  for (auto &V : Values) {
-    if (V.getPointer() == L)
-      return V.getInt();
-  }
-  Values.emplace_back(L, LoopVariant);
-  LoopDisposition D = computeLoopDisposition(S, L);
-  auto &Values2 = LoopDispositions[S];
-  for (auto &V : make_range(Values2.rbegin(), Values2.rend())) {
-    if (V.getPointer() == L) {
-      V.setInt(D);
-      break;
-    }
-  }
-  return D;
-}
-
-ScalarEvolution::LoopDisposition
-ScalarEvolution::computeLoopDisposition(const SCEV *S, const Loop *L) {
-  switch (static_cast<SCEVTypes>(S->getSCEVType())) {
-  case scConstant:
-    return LoopInvariant;
-  case scTruncate:
-  case scZeroExtend:
-  case scSignExtend:
-    return getLoopDisposition(cast<SCEVCastExpr>(S)->getOperand(), L);
-  case scAddRecExpr: {
-    const SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(S);
-
-    // If L is the addrec's loop, it's computable.
-    if (AR->getLoop() == L)
-      return LoopComputable;
-
-    // Add recurrences are never invariant in the function-body (null loop).
-    if (!L)
-      return LoopVariant;
-
-    // Everything that is not defined at loop entry is variant.
-    if (DT.dominates(L->getHeader(), AR->getLoop()->getHeader()))
-      return LoopVariant;
-    assert(!L->contains(AR->getLoop()) && "Containing loop's header does not"
-           " dominate the contained loop's header?");
-
-    // This recurrence is invariant w.r.t. L if AR's loop contains L.
-    if (AR->getLoop()->contains(L))
-      return LoopInvariant;
-
-    // This recurrence is variant w.r.t. L if any of its operands
-    // are variant.
-    for (auto *Op : AR->operands())
-      if (!isLoopInvariant(Op, L))
-        return LoopVariant;
-
-    // Otherwise it's loop-invariant.
-    return LoopInvariant;
-  }
-  case scAddExpr:
-  case scMulExpr:
-  case scUMaxExpr:
-  case scSMaxExpr: {
-    bool HasVarying = false;
-    for (auto *Op : cast<SCEVNAryExpr>(S)->operands()) {
-      LoopDisposition D = getLoopDisposition(Op, L);
-      if (D == LoopVariant)
-        return LoopVariant;
-      if (D == LoopComputable)
-        HasVarying = true;
-    }
-    return HasVarying ? LoopComputable : LoopInvariant;
-  }
-  case scUDivExpr: {
-    const SCEVUDivExpr *UDiv = cast<SCEVUDivExpr>(S);
-    LoopDisposition LD = getLoopDisposition(UDiv->getLHS(), L);
-    if (LD == LoopVariant)
-      return LoopVariant;
-    LoopDisposition RD = getLoopDisposition(UDiv->getRHS(), L);
-    if (RD == LoopVariant)
-      return LoopVariant;
-    return (LD == LoopInvariant && RD == LoopInvariant) ?
-           LoopInvariant : LoopComputable;
-  }
-  case scUnknown:
-    // All non-instruction values are loop invariant.  All instructions are loop
-    // invariant if they are not contained in the specified loop.
-    // Instructions are never considered invariant in the function body
-    // (null loop) because they are defined within the "loop".
-    if (auto *I = dyn_cast<Instruction>(cast<SCEVUnknown>(S)->getValue()))
-      return (L && !L->contains(I)) ? LoopInvariant : LoopVariant;
-    return LoopInvariant;
-  case scCouldNotCompute:
-    llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
-  }
-  llvm_unreachable("Unknown SCEV kind!");
-}
-
-bool ScalarEvolution::isLoopInvariant(const SCEV *S, const Loop *L) {
-  return getLoopDisposition(S, L) == LoopInvariant;
-}
-
-bool ScalarEvolution::hasComputableLoopEvolution(const SCEV *S, const Loop *L) {
-  return getLoopDisposition(S, L) == LoopComputable;
-}
-
-ScalarEvolution::BlockDisposition
-ScalarEvolution::getBlockDisposition(const SCEV *S, const BasicBlock *BB) {
-  auto &Values = BlockDispositions[S];
-  for (auto &V : Values) {
-    if (V.getPointer() == BB)
-      return V.getInt();
-  }
-  Values.emplace_back(BB, DoesNotDominateBlock);
-  BlockDisposition D = computeBlockDisposition(S, BB);
-  auto &Values2 = BlockDispositions[S];
-  for (auto &V : make_range(Values2.rbegin(), Values2.rend())) {
-    if (V.getPointer() == BB) {
-      V.setInt(D);
-      break;
-    }
-  }
-  return D;
-}
-
-ScalarEvolution::BlockDisposition
-ScalarEvolution::computeBlockDisposition(const SCEV *S, const BasicBlock *BB) {
-  switch (static_cast<SCEVTypes>(S->getSCEVType())) {
-  case scConstant:
-    return ProperlyDominatesBlock;
-  case scTruncate:
-  case scZeroExtend:
-  case scSignExtend:
-    return getBlockDisposition(cast<SCEVCastExpr>(S)->getOperand(), BB);
-  case scAddRecExpr: {
-    // This uses a "dominates" query instead of "properly dominates" query
-    // to test for proper dominance too, because the instruction which
-    // produces the addrec's value is a PHI, and a PHI effectively properly
-    // dominates its entire containing block.
-    const SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(S);
-    if (!DT.dominates(AR->getLoop()->getHeader(), BB))
-      return DoesNotDominateBlock;
-
-    // Fall through into SCEVNAryExpr handling.
-    LLVM_FALLTHROUGH;
-  }
-  case scAddExpr:
-  case scMulExpr:
-  case scUMaxExpr:
-  case scSMaxExpr: {
-    const SCEVNAryExpr *NAry = cast<SCEVNAryExpr>(S);
-    bool Proper = true;
-    for (const SCEV *NAryOp : NAry->operands()) {
-      BlockDisposition D = getBlockDisposition(NAryOp, BB);
-      if (D == DoesNotDominateBlock)
-        return DoesNotDominateBlock;
-      if (D == DominatesBlock)
-        Proper = false;
-    }
-    return Proper ? ProperlyDominatesBlock : DominatesBlock;
-  }
-  case scUDivExpr: {
-    const SCEVUDivExpr *UDiv = cast<SCEVUDivExpr>(S);
-    const SCEV *LHS = UDiv->getLHS(), *RHS = UDiv->getRHS();
-    BlockDisposition LD = getBlockDisposition(LHS, BB);
-    if (LD == DoesNotDominateBlock)
-      return DoesNotDominateBlock;
-    BlockDisposition RD = getBlockDisposition(RHS, BB);
-    if (RD == DoesNotDominateBlock)
-      return DoesNotDominateBlock;
-    return (LD == ProperlyDominatesBlock && RD == ProperlyDominatesBlock) ?
-      ProperlyDominatesBlock : DominatesBlock;
-  }
-  case scUnknown:
-    if (Instruction *I =
-          dyn_cast<Instruction>(cast<SCEVUnknown>(S)->getValue())) {
-      if (I->getParent() == BB)
-        return DominatesBlock;
-      if (DT.properlyDominates(I->getParent(), BB))
-        return ProperlyDominatesBlock;
-      return DoesNotDominateBlock;
-    }
-    return ProperlyDominatesBlock;
-  case scCouldNotCompute:
-    llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
-  }
-  llvm_unreachable("Unknown SCEV kind!");
-}
-
-bool ScalarEvolution::dominates(const SCEV *S, const BasicBlock *BB) {
-  return getBlockDisposition(S, BB) >= DominatesBlock;
-}
-
-bool ScalarEvolution::properlyDominates(const SCEV *S, const BasicBlock *BB) {
-  return getBlockDisposition(S, BB) == ProperlyDominatesBlock;
-}
-
-bool ScalarEvolution::hasOperand(const SCEV *S, const SCEV *Op) const {
-  return SCEVExprContains(S, [&](const SCEV *Expr) { return Expr == Op; });
-}
-
-bool ScalarEvolution::ExitLimit::hasOperand(const SCEV *S) const {
-  auto IsS = [&](const SCEV *X) { return S == X; };
-  auto ContainsS = [&](const SCEV *X) {
-    return !isa<SCEVCouldNotCompute>(X) && SCEVExprContains(X, IsS);
-  };
-  return ContainsS(ExactNotTaken) || ContainsS(MaxNotTaken);
-}
-
-void
-ScalarEvolution::forgetMemoizedResults(const SCEV *S) {
-  ValuesAtScopes.erase(S);
-  LoopDispositions.erase(S);
-  BlockDispositions.erase(S);
-  UnsignedRanges.erase(S);
-  SignedRanges.erase(S);
-  ExprValueMap.erase(S);
-  HasRecMap.erase(S);
-  MinTrailingZerosCache.erase(S);
-
-  for (auto I = PredicatedSCEVRewrites.begin();
-       I != PredicatedSCEVRewrites.end();) {
-    std::pair<const SCEV *, const Loop *> Entry = I->first;
-    if (Entry.first == S)
-      PredicatedSCEVRewrites.erase(I++);
-    else
-      ++I;
-  }
-
-  auto RemoveSCEVFromBackedgeMap =
-      [S, this](DenseMap<const Loop *, BackedgeTakenInfo> &Map) {
-        for (auto I = Map.begin(), E = Map.end(); I != E;) {
-          BackedgeTakenInfo &BEInfo = I->second;
-          if (BEInfo.hasOperand(S, this)) {
-            BEInfo.clear();
-            Map.erase(I++);
-          } else
-            ++I;
-        }
-      };
-
-  RemoveSCEVFromBackedgeMap(BackedgeTakenCounts);
-  RemoveSCEVFromBackedgeMap(PredicatedBackedgeTakenCounts);
-}
-
-void
-ScalarEvolution::getUsedLoops(const SCEV *S,
-                              SmallPtrSetImpl<const Loop *> &LoopsUsed) {
-  struct FindUsedLoops {
-    FindUsedLoops(SmallPtrSetImpl<const Loop *> &LoopsUsed)
-        : LoopsUsed(LoopsUsed) {}
-    SmallPtrSetImpl<const Loop *> &LoopsUsed;
-    bool follow(const SCEV *S) {
-      if (auto *AR = dyn_cast<SCEVAddRecExpr>(S))
-        LoopsUsed.insert(AR->getLoop());
-      return true;
-    }
-
-    bool isDone() const { return false; }
-  };
-
-  FindUsedLoops F(LoopsUsed);
-  SCEVTraversal<FindUsedLoops>(F).visitAll(S);
-}
-
-void ScalarEvolution::addToLoopUseLists(const SCEV *S) {
-  SmallPtrSet<const Loop *, 8> LoopsUsed;
-  getUsedLoops(S, LoopsUsed);
-  for (auto *L : LoopsUsed)
-    LoopUsers[L].push_back(S);
-}
-
-void ScalarEvolution::verify() const {
-  ScalarEvolution &SE = *const_cast<ScalarEvolution *>(this);
-  ScalarEvolution SE2(F, TLI, AC, DT, LI);
-
-  SmallVector<Loop *, 8> LoopStack(LI.begin(), LI.end());
-
-  // Map's SCEV expressions from one ScalarEvolution "universe" to another.
-  struct SCEVMapper : public SCEVRewriteVisitor<SCEVMapper> {
-    SCEVMapper(ScalarEvolution &SE) : SCEVRewriteVisitor<SCEVMapper>(SE) {}
-
-    const SCEV *visitConstant(const SCEVConstant *Constant) {
-      return SE.getConstant(Constant->getAPInt());
-    }
-
-    const SCEV *visitUnknown(const SCEVUnknown *Expr) {
-      return SE.getUnknown(Expr->getValue());
-    }
-
-    const SCEV *visitCouldNotCompute(const SCEVCouldNotCompute *Expr) {
-      return SE.getCouldNotCompute();
-    }
-  };
-
-  SCEVMapper SCM(SE2);
-
-  while (!LoopStack.empty()) {
-    auto *L = LoopStack.pop_back_val();
-    LoopStack.insert(LoopStack.end(), L->begin(), L->end());
-
-    auto *CurBECount = SCM.visit(
-        const_cast<ScalarEvolution *>(this)->getBackedgeTakenCount(L));
-    auto *NewBECount = SE2.getBackedgeTakenCount(L);
-
-    if (CurBECount == SE2.getCouldNotCompute() ||
-        NewBECount == SE2.getCouldNotCompute()) {
-      // NB! This situation is legal, but is very suspicious -- whatever pass
-      // change the loop to make a trip count go from could not compute to
-      // computable or vice-versa *should have* invalidated SCEV.  However, we
-      // choose not to assert here (for now) since we don't want false
-      // positives.
-      continue;
-    }
-
-    if (containsUndefs(CurBECount) || containsUndefs(NewBECount)) {
-      // SCEV treats "undef" as an unknown but consistent value (i.e. it does
-      // not propagate undef aggressively).  This means we can (and do) fail
-      // verification in cases where a transform makes the trip count of a loop
-      // go from "undef" to "undef+1" (say).  The transform is fine, since in
-      // both cases the loop iterates "undef" times, but SCEV thinks we
-      // increased the trip count of the loop by 1 incorrectly.
-      continue;
-    }
-
-    if (SE.getTypeSizeInBits(CurBECount->getType()) >
-        SE.getTypeSizeInBits(NewBECount->getType()))
-      NewBECount = SE2.getZeroExtendExpr(NewBECount, CurBECount->getType());
-    else if (SE.getTypeSizeInBits(CurBECount->getType()) <
-             SE.getTypeSizeInBits(NewBECount->getType()))
-      CurBECount = SE2.getZeroExtendExpr(CurBECount, NewBECount->getType());
-
-    auto *ConstantDelta =
-        dyn_cast<SCEVConstant>(SE2.getMinusSCEV(CurBECount, NewBECount));
-
-    if (ConstantDelta && ConstantDelta->getAPInt() != 0) {
-      dbgs() << "Trip Count Changed!\n";
-      dbgs() << "Old: " << *CurBECount << "\n";
-      dbgs() << "New: " << *NewBECount << "\n";
-      dbgs() << "Delta: " << *ConstantDelta << "\n";
-      std::abort();
-    }
-  }
-}
-
-bool ScalarEvolution::invalidate(
-    Function &F, const PreservedAnalyses &PA,
-    FunctionAnalysisManager::Invalidator &Inv) {
-  // Invalidate the ScalarEvolution object whenever it isn't preserved or one
-  // of its dependencies is invalidated.
-  auto PAC = PA.getChecker<ScalarEvolutionAnalysis>();
-  return !(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Function>>()) ||
-         Inv.invalidate<AssumptionAnalysis>(F, PA) ||
-         Inv.invalidate<DominatorTreeAnalysis>(F, PA) ||
-         Inv.invalidate<LoopAnalysis>(F, PA);
-}
-
-AnalysisKey ScalarEvolutionAnalysis::Key;
-
-ScalarEvolution ScalarEvolutionAnalysis::run(Function &F,
-                                             FunctionAnalysisManager &AM) {
-  return ScalarEvolution(F, AM.getResult<TargetLibraryAnalysis>(F),
-                         AM.getResult<AssumptionAnalysis>(F),
-                         AM.getResult<DominatorTreeAnalysis>(F),
-                         AM.getResult<LoopAnalysis>(F));
-}
-
-PreservedAnalyses
-ScalarEvolutionPrinterPass::run(Function &F, FunctionAnalysisManager &AM) {
-  AM.getResult<ScalarEvolutionAnalysis>(F).print(OS);
-  return PreservedAnalyses::all();
-}
-
-INITIALIZE_PASS_BEGIN(ScalarEvolutionWrapperPass, "scalar-evolution",
-                      "Scalar Evolution Analysis", false, true)
-INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
-INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
-INITIALIZE_PASS_END(ScalarEvolutionWrapperPass, "scalar-evolution",
-                    "Scalar Evolution Analysis", false, true)
-
-char ScalarEvolutionWrapperPass::ID = 0;
-
-ScalarEvolutionWrapperPass::ScalarEvolutionWrapperPass() : FunctionPass(ID) {
-  initializeScalarEvolutionWrapperPassPass(*PassRegistry::getPassRegistry());
-}
-
-bool ScalarEvolutionWrapperPass::runOnFunction(Function &F) {
-  SE.reset(new ScalarEvolution(
-      F, getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(),
-      getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F),
-      getAnalysis<DominatorTreeWrapperPass>().getDomTree(),
-      getAnalysis<LoopInfoWrapperPass>().getLoopInfo()));
-  return false;
-}
-
-void ScalarEvolutionWrapperPass::releaseMemory() { SE.reset(); }
-
-void ScalarEvolutionWrapperPass::print(raw_ostream &OS, const Module *) const {
-  SE->print(OS);
-}
-
-void ScalarEvolutionWrapperPass::verifyAnalysis() const {
-  if (!VerifySCEV)
-    return;
-
-  SE->verify();
-}
-
-void ScalarEvolutionWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
-  AU.setPreservesAll();
-  AU.addRequiredTransitive<AssumptionCacheTracker>();
-  AU.addRequiredTransitive<LoopInfoWrapperPass>();
-  AU.addRequiredTransitive<DominatorTreeWrapperPass>();
-  AU.addRequiredTransitive<TargetLibraryInfoWrapperPass>();
-}
-
-const SCEVPredicate *ScalarEvolution::getEqualPredicate(const SCEV *LHS,
-                                                        const SCEV *RHS) {
-  FoldingSetNodeID ID;
-  assert(LHS->getType() == RHS->getType() &&
-         "Type mismatch between LHS and RHS");
-  // Unique this node based on the arguments
-  ID.AddInteger(SCEVPredicate::P_Equal);
-  ID.AddPointer(LHS);
-  ID.AddPointer(RHS);
-  void *IP = nullptr;
-  if (const auto *S = UniquePreds.FindNodeOrInsertPos(ID, IP))
-    return S;
-  SCEVEqualPredicate *Eq = new (SCEVAllocator)
-      SCEVEqualPredicate(ID.Intern(SCEVAllocator), LHS, RHS);
-  UniquePreds.InsertNode(Eq, IP);
-  return Eq;
-}
-
-const SCEVPredicate *ScalarEvolution::getWrapPredicate(
-    const SCEVAddRecExpr *AR,
-    SCEVWrapPredicate::IncrementWrapFlags AddedFlags) {
-  FoldingSetNodeID ID;
-  // Unique this node based on the arguments
-  ID.AddInteger(SCEVPredicate::P_Wrap);
-  ID.AddPointer(AR);
-  ID.AddInteger(AddedFlags);
-  void *IP = nullptr;
-  if (const auto *S = UniquePreds.FindNodeOrInsertPos(ID, IP))
-    return S;
-  auto *OF = new (SCEVAllocator)
-      SCEVWrapPredicate(ID.Intern(SCEVAllocator), AR, AddedFlags);
-  UniquePreds.InsertNode(OF, IP);
-  return OF;
-}
-
-namespace {
-
-class SCEVPredicateRewriter : public SCEVRewriteVisitor<SCEVPredicateRewriter> {
-public:
-
-  /// Rewrites \p S in the context of a loop L and the SCEV predication
-  /// infrastructure.
-  ///
-  /// If \p Pred is non-null, the SCEV expression is rewritten to respect the
-  /// equivalences present in \p Pred.
-  ///
-  /// If \p NewPreds is non-null, rewrite is free to add further predicates to
-  /// \p NewPreds such that the result will be an AddRecExpr.
-  static const SCEV *rewrite(const SCEV *S, const Loop *L, ScalarEvolution &SE,
-                             SmallPtrSetImpl<const SCEVPredicate *> *NewPreds,
-                             SCEVUnionPredicate *Pred) {
-    SCEVPredicateRewriter Rewriter(L, SE, NewPreds, Pred);
-    return Rewriter.visit(S);
-  }
-
-  const SCEV *visitUnknown(const SCEVUnknown *Expr) {
-    if (Pred) {
-      auto ExprPreds = Pred->getPredicatesForExpr(Expr);
-      for (auto *Pred : ExprPreds)
-        if (const auto *IPred = dyn_cast<SCEVEqualPredicate>(Pred))
-          if (IPred->getLHS() == Expr)
-            return IPred->getRHS();
-    }
-    return convertToAddRecWithPreds(Expr);
-  }
-
-  const SCEV *visitZeroExtendExpr(const SCEVZeroExtendExpr *Expr) {
-    const SCEV *Operand = visit(Expr->getOperand());
-    const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Operand);
-    if (AR && AR->getLoop() == L && AR->isAffine()) {
-      // This couldn't be folded because the operand didn't have the nuw
-      // flag. Add the nusw flag as an assumption that we could make.
-      const SCEV *Step = AR->getStepRecurrence(SE);
-      Type *Ty = Expr->getType();
-      if (addOverflowAssumption(AR, SCEVWrapPredicate::IncrementNUSW))
-        return SE.getAddRecExpr(SE.getZeroExtendExpr(AR->getStart(), Ty),
-                                SE.getSignExtendExpr(Step, Ty), L,
-                                AR->getNoWrapFlags());
-    }
-    return SE.getZeroExtendExpr(Operand, Expr->getType());
-  }
-
-  const SCEV *visitSignExtendExpr(const SCEVSignExtendExpr *Expr) {
-    const SCEV *Operand = visit(Expr->getOperand());
-    const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Operand);
-    if (AR && AR->getLoop() == L && AR->isAffine()) {
-      // This couldn't be folded because the operand didn't have the nsw
-      // flag. Add the nssw flag as an assumption that we could make.
-      const SCEV *Step = AR->getStepRecurrence(SE);
-      Type *Ty = Expr->getType();
-      if (addOverflowAssumption(AR, SCEVWrapPredicate::IncrementNSSW))
-        return SE.getAddRecExpr(SE.getSignExtendExpr(AR->getStart(), Ty),
-                                SE.getSignExtendExpr(Step, Ty), L,
-                                AR->getNoWrapFlags());
-    }
-    return SE.getSignExtendExpr(Operand, Expr->getType());
-  }
-
-private:
-  explicit SCEVPredicateRewriter(const Loop *L, ScalarEvolution &SE,
-                        SmallPtrSetImpl<const SCEVPredicate *> *NewPreds,
-                        SCEVUnionPredicate *Pred)
-      : SCEVRewriteVisitor(SE), NewPreds(NewPreds), Pred(Pred), L(L) {}
-
-  bool addOverflowAssumption(const SCEVPredicate *P) {
-    if (!NewPreds) {
-      // Check if we've already made this assumption.
-      return Pred && Pred->implies(P);
-    }
-    NewPreds->insert(P);
-    return true;
-  }
-
-  bool addOverflowAssumption(const SCEVAddRecExpr *AR,
-                             SCEVWrapPredicate::IncrementWrapFlags AddedFlags) {
-    auto *A = SE.getWrapPredicate(AR, AddedFlags);
-    return addOverflowAssumption(A);
-  }
-
-  // If \p Expr represents a PHINode, we try to see if it can be represented
-  // as an AddRec, possibly under a predicate (PHISCEVPred). If it is possible
-  // to add this predicate as a runtime overflow check, we return the AddRec.
-  // If \p Expr does not meet these conditions (is not a PHI node, or we
-  // couldn't create an AddRec for it, or couldn't add the predicate), we just
-  // return \p Expr.
-  const SCEV *convertToAddRecWithPreds(const SCEVUnknown *Expr) {
-    if (!isa<PHINode>(Expr->getValue()))
-      return Expr;
-    Optional<std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>>>
-    PredicatedRewrite = SE.createAddRecFromPHIWithCasts(Expr);
-    if (!PredicatedRewrite)
-      return Expr;
-    for (auto *P : PredicatedRewrite->second){
-      // Wrap predicates from outer loops are not supported.
-      if (auto *WP = dyn_cast<const SCEVWrapPredicate>(P)) {
-        auto *AR = cast<const SCEVAddRecExpr>(WP->getExpr());
-        if (L != AR->getLoop())
-          return Expr;
-      }
-      if (!addOverflowAssumption(P))
-        return Expr;
-    }
-    return PredicatedRewrite->first;
-  }
-
-  SmallPtrSetImpl<const SCEVPredicate *> *NewPreds;
-  SCEVUnionPredicate *Pred;
-  const Loop *L;
-};
-
-} // end anonymous namespace
-
-const SCEV *ScalarEvolution::rewriteUsingPredicate(const SCEV *S, const Loop *L,
-                                                   SCEVUnionPredicate &Preds) {
-  return SCEVPredicateRewriter::rewrite(S, L, *this, nullptr, &Preds);
-}
-
-const SCEVAddRecExpr *ScalarEvolution::convertSCEVToAddRecWithPredicates(
-    const SCEV *S, const Loop *L,
-    SmallPtrSetImpl<const SCEVPredicate *> &Preds) {
-  SmallPtrSet<const SCEVPredicate *, 4> TransformPreds;
-  S = SCEVPredicateRewriter::rewrite(S, L, *this, &TransformPreds, nullptr);
-  auto *AddRec = dyn_cast<SCEVAddRecExpr>(S);
-
-  if (!AddRec)
-    return nullptr;
-
-  // Since the transformation was successful, we can now transfer the SCEV
-  // predicates.
-  for (auto *P : TransformPreds)
-    Preds.insert(P);
-
-  return AddRec;
-}
-
-/// SCEV predicates
-SCEVPredicate::SCEVPredicate(const FoldingSetNodeIDRef ID,
-                             SCEVPredicateKind Kind)
-    : FastID(ID), Kind(Kind) {}
-
-SCEVEqualPredicate::SCEVEqualPredicate(const FoldingSetNodeIDRef ID,
-                                       const SCEV *LHS, const SCEV *RHS)
-    : SCEVPredicate(ID, P_Equal), LHS(LHS), RHS(RHS) {
-  assert(LHS->getType() == RHS->getType() && "LHS and RHS types don't match");
-  assert(LHS != RHS && "LHS and RHS are the same SCEV");
-}
-
-bool SCEVEqualPredicate::implies(const SCEVPredicate *N) const {
-  const auto *Op = dyn_cast<SCEVEqualPredicate>(N);
-
-  if (!Op)
-    return false;
-
-  return Op->LHS == LHS && Op->RHS == RHS;
-}
-
-bool SCEVEqualPredicate::isAlwaysTrue() const { return false; }
-
-const SCEV *SCEVEqualPredicate::getExpr() const { return LHS; }
-
-void SCEVEqualPredicate::print(raw_ostream &OS, unsigned Depth) const {
-  OS.indent(Depth) << "Equal predicate: " << *LHS << " == " << *RHS << "\n";
-}
-
-SCEVWrapPredicate::SCEVWrapPredicate(const FoldingSetNodeIDRef ID,
-                                     const SCEVAddRecExpr *AR,
-                                     IncrementWrapFlags Flags)
-    : SCEVPredicate(ID, P_Wrap), AR(AR), Flags(Flags) {}
-
-const SCEV *SCEVWrapPredicate::getExpr() const { return AR; }
-
-bool SCEVWrapPredicate::implies(const SCEVPredicate *N) const {
-  const auto *Op = dyn_cast<SCEVWrapPredicate>(N);
-
-  return Op && Op->AR == AR && setFlags(Flags, Op->Flags) == Flags;
-}
-
-bool SCEVWrapPredicate::isAlwaysTrue() const {
-  SCEV::NoWrapFlags ScevFlags = AR->getNoWrapFlags();
-  IncrementWrapFlags IFlags = Flags;
-
-  if (ScalarEvolution::setFlags(ScevFlags, SCEV::FlagNSW) == ScevFlags)
-    IFlags = clearFlags(IFlags, IncrementNSSW);
-
-  return IFlags == IncrementAnyWrap;
-}
-
-void SCEVWrapPredicate::print(raw_ostream &OS, unsigned Depth) const {
-  OS.indent(Depth) << *getExpr() << " Added Flags: ";
-  if (SCEVWrapPredicate::IncrementNUSW & getFlags())
-    OS << "<nusw>";
-  if (SCEVWrapPredicate::IncrementNSSW & getFlags())
-    OS << "<nssw>";
-  OS << "\n";
-}
-
-SCEVWrapPredicate::IncrementWrapFlags
-SCEVWrapPredicate::getImpliedFlags(const SCEVAddRecExpr *AR,
-                                   ScalarEvolution &SE) {
-  IncrementWrapFlags ImpliedFlags = IncrementAnyWrap;
-  SCEV::NoWrapFlags StaticFlags = AR->getNoWrapFlags();
-
-  // We can safely transfer the NSW flag as NSSW.
-  if (ScalarEvolution::setFlags(StaticFlags, SCEV::FlagNSW) == StaticFlags)
-    ImpliedFlags = IncrementNSSW;
-
-  if (ScalarEvolution::setFlags(StaticFlags, SCEV::FlagNUW) == StaticFlags) {
-    // If the increment is positive, the SCEV NUW flag will also imply the
-    // WrapPredicate NUSW flag.
-    if (const auto *Step = dyn_cast<SCEVConstant>(AR->getStepRecurrence(SE)))
-      if (Step->getValue()->getValue().isNonNegative())
-        ImpliedFlags = setFlags(ImpliedFlags, IncrementNUSW);
-  }
-
-  return ImpliedFlags;
-}
-
-/// Union predicates don't get cached so create a dummy set ID for it.
-SCEVUnionPredicate::SCEVUnionPredicate()
-    : SCEVPredicate(FoldingSetNodeIDRef(nullptr, 0), P_Union) {}
-
-bool SCEVUnionPredicate::isAlwaysTrue() const {
-  return all_of(Preds,
-                [](const SCEVPredicate *I) { return I->isAlwaysTrue(); });
-}
-
-ArrayRef<const SCEVPredicate *>
-SCEVUnionPredicate::getPredicatesForExpr(const SCEV *Expr) {
-  auto I = SCEVToPreds.find(Expr);
-  if (I == SCEVToPreds.end())
-    return ArrayRef<const SCEVPredicate *>();
-  return I->second;
-}
-
-bool SCEVUnionPredicate::implies(const SCEVPredicate *N) const {
-  if (const auto *Set = dyn_cast<SCEVUnionPredicate>(N))
-    return all_of(Set->Preds,
-                  [this](const SCEVPredicate *I) { return this->implies(I); });
-
-  auto ScevPredsIt = SCEVToPreds.find(N->getExpr());
-  if (ScevPredsIt == SCEVToPreds.end())
-    return false;
-  auto &SCEVPreds = ScevPredsIt->second;
-
-  return any_of(SCEVPreds,
-                [N](const SCEVPredicate *I) { return I->implies(N); });
-}
-
-const SCEV *SCEVUnionPredicate::getExpr() const { return nullptr; }
-
-void SCEVUnionPredicate::print(raw_ostream &OS, unsigned Depth) const {
-  for (auto Pred : Preds)
-    Pred->print(OS, Depth);
-}
-
-void SCEVUnionPredicate::add(const SCEVPredicate *N) {
-  if (const auto *Set = dyn_cast<SCEVUnionPredicate>(N)) {
-    for (auto Pred : Set->Preds)
-      add(Pred);
-    return;
-  }
-
-  if (implies(N))
-    return;
-
-  const SCEV *Key = N->getExpr();
-  assert(Key && "Only SCEVUnionPredicate doesn't have an "
-                " associated expression!");
-
-  SCEVToPreds[Key].push_back(N);
-  Preds.push_back(N);
-}
-
-PredicatedScalarEvolution::PredicatedScalarEvolution(ScalarEvolution &SE,
-                                                     Loop &L)
-    : SE(SE), L(L) {}
-
-const SCEV *PredicatedScalarEvolution::getSCEV(Value *V) {
-  const SCEV *Expr = SE.getSCEV(V);
-  RewriteEntry &Entry = RewriteMap[Expr];
-
-  // If we already have an entry and the version matches, return it.
-  if (Entry.second && Generation == Entry.first)
-    return Entry.second;
-
-  // We found an entry but it's stale. Rewrite the stale entry
-  // according to the current predicate.
-  if (Entry.second)
-    Expr = Entry.second;
-
-  const SCEV *NewSCEV = SE.rewriteUsingPredicate(Expr, &L, Preds);
-  Entry = {Generation, NewSCEV};
-
-  return NewSCEV;
-}
-
-const SCEV *PredicatedScalarEvolution::getBackedgeTakenCount() {
-  if (!BackedgeCount) {
-    SCEVUnionPredicate BackedgePred;
-    BackedgeCount = SE.getPredicatedBackedgeTakenCount(&L, BackedgePred);
-    addPredicate(BackedgePred);
-  }
-  return BackedgeCount;
-}
-
-void PredicatedScalarEvolution::addPredicate(const SCEVPredicate &Pred) {
-  if (Preds.implies(&Pred))
-    return;
-  Preds.add(&Pred);
-  updateGeneration();
-}
-
-const SCEVUnionPredicate &PredicatedScalarEvolution::getUnionPredicate() const {
-  return Preds;
-}
-
-void PredicatedScalarEvolution::updateGeneration() {
-  // If the generation number wrapped recompute everything.
-  if (++Generation == 0) {
-    for (auto &II : RewriteMap) {
-      const SCEV *Rewritten = II.second.second;
-      II.second = {Generation, SE.rewriteUsingPredicate(Rewritten, &L, Preds)};
-    }
-  }
-}
-
-void PredicatedScalarEvolution::setNoOverflow(
-    Value *V, SCEVWrapPredicate::IncrementWrapFlags Flags) {
-  const SCEV *Expr = getSCEV(V);
-  const auto *AR = cast<SCEVAddRecExpr>(Expr);
-
-  auto ImpliedFlags = SCEVWrapPredicate::getImpliedFlags(AR, SE);
-
-  // Clear the statically implied flags.
-  Flags = SCEVWrapPredicate::clearFlags(Flags, ImpliedFlags);
-  addPredicate(*SE.getWrapPredicate(AR, Flags));
-
-  auto II = FlagsMap.insert({V, Flags});
-  if (!II.second)
-    II.first->second = SCEVWrapPredicate::setFlags(Flags, II.first->second);
-}
-
-bool PredicatedScalarEvolution::hasNoOverflow(
-    Value *V, SCEVWrapPredicate::IncrementWrapFlags Flags) {
-  const SCEV *Expr = getSCEV(V);
-  const auto *AR = cast<SCEVAddRecExpr>(Expr);
-
-  Flags = SCEVWrapPredicate::clearFlags(
-      Flags, SCEVWrapPredicate::getImpliedFlags(AR, SE));
-
-  auto II = FlagsMap.find(V);
-
-  if (II != FlagsMap.end())
-    Flags = SCEVWrapPredicate::clearFlags(Flags, II->second);
-
-  return Flags == SCEVWrapPredicate::IncrementAnyWrap;
-}
-
-const SCEVAddRecExpr *PredicatedScalarEvolution::getAsAddRec(Value *V) {
-  const SCEV *Expr = this->getSCEV(V);
-  SmallPtrSet<const SCEVPredicate *, 4> NewPreds;
-  auto *New = SE.convertSCEVToAddRecWithPredicates(Expr, &L, NewPreds);
-
-  if (!New)
-    return nullptr;
-
-  for (auto *P : NewPreds)
-    Preds.add(P);
-
-  updateGeneration();
-  RewriteMap[SE.getSCEV(V)] = {Generation, New};
-  return New;
-}
-
-PredicatedScalarEvolution::PredicatedScalarEvolution(
-    const PredicatedScalarEvolution &Init)
-    : RewriteMap(Init.RewriteMap), SE(Init.SE), L(Init.L), Preds(Init.Preds),
-      Generation(Init.Generation), BackedgeCount(Init.BackedgeCount) {
-  for (const auto &I : Init.FlagsMap)
-    FlagsMap.insert(I);
-}
-
-void PredicatedScalarEvolution::print(raw_ostream &OS, unsigned Depth) const {
-  // For each block.
-  for (auto *BB : L.getBlocks())
-    for (auto &I : *BB) {
-      if (!SE.isSCEVable(I.getType()))
-        continue;
-
-      auto *Expr = SE.getSCEV(&I);
-      auto II = RewriteMap.find(Expr);
-
-      if (II == RewriteMap.end())
-        continue;
-
-      // Don't print things that are not interesting.
-      if (II->second.second == Expr)
-        continue;
-
-      OS.indent(Depth) << "[PSE]" << I << ":\n";
-      OS.indent(Depth + 2) << *Expr << "\n";
-      OS.indent(Depth + 2) << "--> " << *II->second.second << "\n";
-    }
-}
-
-// Match the mathematical pattern A - (A / B) * B, where A and B can be
-// arbitrary expressions.
-// It's not always easy, as A and B can be folded (imagine A is X / 2, and B is
-// 4, A / B becomes X / 8).
-bool ScalarEvolution::matchURem(const SCEV *Expr, const SCEV *&LHS,
-                                const SCEV *&RHS) {
-  const auto *Add = dyn_cast<SCEVAddExpr>(Expr);
-  if (Add == nullptr || Add->getNumOperands() != 2)
-    return false;
-
-  const SCEV *A = Add->getOperand(1);
-  const auto *Mul = dyn_cast<SCEVMulExpr>(Add->getOperand(0));
-
-  if (Mul == nullptr)
-    return false;
-
-  const auto MatchURemWithDivisor = [&](const SCEV *B) {
-    // (SomeExpr + (-(SomeExpr / B) * B)).
-    if (Expr == getURemExpr(A, B)) {
-      LHS = A;
-      RHS = B;
-      return true;
-    }
-    return false;
-  };
-
-  // (SomeExpr + (-1 * (SomeExpr / B) * B)).
-  if (Mul->getNumOperands() == 3 && isa<SCEVConstant>(Mul->getOperand(0)))
-    return MatchURemWithDivisor(Mul->getOperand(1)) ||
-           MatchURemWithDivisor(Mul->getOperand(2));
-
-  // (SomeExpr + ((-SomeExpr / B) * B)) or (SomeExpr + ((SomeExpr / B) * -B)).
-  if (Mul->getNumOperands() == 2)
-    return MatchURemWithDivisor(Mul->getOperand(1)) ||
-           MatchURemWithDivisor(Mul->getOperand(0)) ||
-           MatchURemWithDivisor(getNegativeSCEV(Mul->getOperand(1))) ||
-           MatchURemWithDivisor(getNegativeSCEV(Mul->getOperand(0)));
-  return false;
-}