Use the space freed up by sparc and zaurus to import LLVM.

ok hackroom@

1 files changed, 2759 insertions, 0 deletions

diff --git a/gnu/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/gnu/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
new file mode 100644
index 00000000000..76cefd97cd8
--- /dev/null
+++ b/gnu/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -0,0 +1,2759 @@
+//===- InstCombineAndOrXor.cpp --------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the visitAnd, visitOr, and visitXor functions.
+//
+//===----------------------------------------------------------------------===//
+
+#include "InstCombineInternal.h"
+#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/IR/ConstantRange.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/PatternMatch.h"
+#include "llvm/Transforms/Utils/CmpInstAnalysis.h"
+#include "llvm/Transforms/Utils/Local.h"
+using namespace llvm;
+using namespace PatternMatch;
+
+#define DEBUG_TYPE "instcombine"
+
+static inline Value *dyn_castNotVal(Value *V) {
+  // If this is not(not(x)) don't return that this is a not: we want the two
+  // not's to be folded first.
+  if (BinaryOperator::isNot(V)) {
+    Value *Operand = BinaryOperator::getNotArgument(V);
+    if (!IsFreeToInvert(Operand, Operand->hasOneUse()))
+      return Operand;
+  }
+
+  // Constants can be considered to be not'ed values...
+  if (ConstantInt *C = dyn_cast<ConstantInt>(V))
+    return ConstantInt::get(C->getType(), ~C->getValue());
+  return nullptr;
+}
+
+/// Similar to getICmpCode but for FCmpInst. This encodes a fcmp predicate into
+/// a three bit mask. It also returns whether it is an ordered predicate by
+/// reference.
+static unsigned getFCmpCode(FCmpInst::Predicate CC, bool &isOrdered) {
+  isOrdered = false;
+  switch (CC) {
+  case FCmpInst::FCMP_ORD: isOrdered = true; return 0;  // 000
+  case FCmpInst::FCMP_UNO:                   return 0;  // 000
+  case FCmpInst::FCMP_OGT: isOrdered = true; return 1;  // 001
+  case FCmpInst::FCMP_UGT:                   return 1;  // 001
+  case FCmpInst::FCMP_OEQ: isOrdered = true; return 2;  // 010
+  case FCmpInst::FCMP_UEQ:                   return 2;  // 010
+  case FCmpInst::FCMP_OGE: isOrdered = true; return 3;  // 011
+  case FCmpInst::FCMP_UGE:                   return 3;  // 011
+  case FCmpInst::FCMP_OLT: isOrdered = true; return 4;  // 100
+  case FCmpInst::FCMP_ULT:                   return 4;  // 100
+  case FCmpInst::FCMP_ONE: isOrdered = true; return 5;  // 101
+  case FCmpInst::FCMP_UNE:                   return 5;  // 101
+  case FCmpInst::FCMP_OLE: isOrdered = true; return 6;  // 110
+  case FCmpInst::FCMP_ULE:                   return 6;  // 110
+    // True -> 7
+  default:
+    // Not expecting FCMP_FALSE and FCMP_TRUE;
+    llvm_unreachable("Unexpected FCmp predicate!");
+  }
+}
+
+/// This is the complement of getICmpCode, which turns an opcode and two
+/// operands into either a constant true or false, or a brand new ICmp
+/// instruction. The sign is passed in to determine which kind of predicate to
+/// use in the new icmp instruction.
+static Value *getNewICmpValue(bool Sign, unsigned Code, Value *LHS, Value *RHS,
+                              InstCombiner::BuilderTy *Builder) {
+  ICmpInst::Predicate NewPred;
+  if (Value *NewConstant = getICmpValue(Sign, Code, LHS, RHS, NewPred))
+    return NewConstant;
+  return Builder->CreateICmp(NewPred, LHS, RHS);
+}
+
+/// This is the complement of getFCmpCode, which turns an opcode and two
+/// operands into either a FCmp instruction. isordered is passed in to determine
+/// which kind of predicate to use in the new fcmp instruction.
+static Value *getFCmpValue(bool isordered, unsigned code,
+                           Value *LHS, Value *RHS,
+                           InstCombiner::BuilderTy *Builder) {
+  CmpInst::Predicate Pred;
+  switch (code) {
+  default: llvm_unreachable("Illegal FCmp code!");
+  case 0: Pred = isordered ? FCmpInst::FCMP_ORD : FCmpInst::FCMP_UNO; break;
+  case 1: Pred = isordered ? FCmpInst::FCMP_OGT : FCmpInst::FCMP_UGT; break;
+  case 2: Pred = isordered ? FCmpInst::FCMP_OEQ : FCmpInst::FCMP_UEQ; break;
+  case 3: Pred = isordered ? FCmpInst::FCMP_OGE : FCmpInst::FCMP_UGE; break;
+  case 4: Pred = isordered ? FCmpInst::FCMP_OLT : FCmpInst::FCMP_ULT; break;
+  case 5: Pred = isordered ? FCmpInst::FCMP_ONE : FCmpInst::FCMP_UNE; break;
+  case 6: Pred = isordered ? FCmpInst::FCMP_OLE : FCmpInst::FCMP_ULE; break;
+  case 7:
+    if (!isordered)
+      return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 1);
+    Pred = FCmpInst::FCMP_ORD; break;
+  }
+  return Builder->CreateFCmp(Pred, LHS, RHS);
+}
+
+/// \brief Transform BITWISE_OP(BSWAP(A),BSWAP(B)) to BSWAP(BITWISE_OP(A, B))
+/// \param I Binary operator to transform.
+/// \return Pointer to node that must replace the original binary operator, or
+///         null pointer if no transformation was made.
+Value *InstCombiner::SimplifyBSwap(BinaryOperator &I) {
+  IntegerType *ITy = dyn_cast<IntegerType>(I.getType());
+
+  // Can't do vectors.
+  if (I.getType()->isVectorTy()) return nullptr;
+
+  // Can only do bitwise ops.
+  unsigned Op = I.getOpcode();
+  if (Op != Instruction::And && Op != Instruction::Or &&
+      Op != Instruction::Xor)
+    return nullptr;
+
+  Value *OldLHS = I.getOperand(0);
+  Value *OldRHS = I.getOperand(1);
+  ConstantInt *ConstLHS = dyn_cast<ConstantInt>(OldLHS);
+  ConstantInt *ConstRHS = dyn_cast<ConstantInt>(OldRHS);
+  IntrinsicInst *IntrLHS = dyn_cast<IntrinsicInst>(OldLHS);
+  IntrinsicInst *IntrRHS = dyn_cast<IntrinsicInst>(OldRHS);
+  bool IsBswapLHS = (IntrLHS && IntrLHS->getIntrinsicID() == Intrinsic::bswap);
+  bool IsBswapRHS = (IntrRHS && IntrRHS->getIntrinsicID() == Intrinsic::bswap);
+
+  if (!IsBswapLHS && !IsBswapRHS)
+    return nullptr;
+
+  if (!IsBswapLHS && !ConstLHS)
+    return nullptr;
+
+  if (!IsBswapRHS && !ConstRHS)
+    return nullptr;
+
+  /// OP( BSWAP(x), BSWAP(y) ) -> BSWAP( OP(x, y) )
+  /// OP( BSWAP(x), CONSTANT ) -> BSWAP( OP(x, BSWAP(CONSTANT) ) )
+  Value *NewLHS = IsBswapLHS ? IntrLHS->getOperand(0) :
+                  Builder->getInt(ConstLHS->getValue().byteSwap());
+
+  Value *NewRHS = IsBswapRHS ? IntrRHS->getOperand(0) :
+                  Builder->getInt(ConstRHS->getValue().byteSwap());
+
+  Value *BinOp = nullptr;
+  if (Op == Instruction::And)
+    BinOp = Builder->CreateAnd(NewLHS, NewRHS);
+  else if (Op == Instruction::Or)
+    BinOp = Builder->CreateOr(NewLHS, NewRHS);
+  else //if (Op == Instruction::Xor)
+    BinOp = Builder->CreateXor(NewLHS, NewRHS);
+
+  Function *F = Intrinsic::getDeclaration(I.getModule(), Intrinsic::bswap, ITy);
+  return Builder->CreateCall(F, BinOp);
+}
+
+/// This handles expressions of the form ((val OP C1) & C2).  Where
+/// the Op parameter is 'OP', OpRHS is 'C1', and AndRHS is 'C2'.  Op is
+/// guaranteed to be a binary operator.
+Instruction *InstCombiner::OptAndOp(Instruction *Op,
+                                    ConstantInt *OpRHS,
+                                    ConstantInt *AndRHS,
+                                    BinaryOperator &TheAnd) {
+  Value *X = Op->getOperand(0);
+  Constant *Together = nullptr;
+  if (!Op->isShift())
+    Together = ConstantExpr::getAnd(AndRHS, OpRHS);
+
+  switch (Op->getOpcode()) {
+  case Instruction::Xor:
+    if (Op->hasOneUse()) {
+      // (X ^ C1) & C2 --> (X & C2) ^ (C1&C2)
+      Value *And = Builder->CreateAnd(X, AndRHS);
+      And->takeName(Op);
+      return BinaryOperator::CreateXor(And, Together);
+    }
+    break;
+  case Instruction::Or:
+    if (Op->hasOneUse()){
+      if (Together != OpRHS) {
+        // (X | C1) & C2 --> (X | (C1&C2)) & C2
+        Value *Or = Builder->CreateOr(X, Together);
+        Or->takeName(Op);
+        return BinaryOperator::CreateAnd(Or, AndRHS);
+      }
+
+      ConstantInt *TogetherCI = dyn_cast<ConstantInt>(Together);
+      if (TogetherCI && !TogetherCI->isZero()){
+        // (X | C1) & C2 --> (X & (C2^(C1&C2))) | C1
+        // NOTE: This reduces the number of bits set in the & mask, which
+        // can expose opportunities for store narrowing.
+        Together = ConstantExpr::getXor(AndRHS, Together);
+        Value *And = Builder->CreateAnd(X, Together);
+        And->takeName(Op);
+        return BinaryOperator::CreateOr(And, OpRHS);
+      }
+    }
+
+    break;
+  case Instruction::Add:
+    if (Op->hasOneUse()) {
+      // Adding a one to a single bit bit-field should be turned into an XOR
+      // of the bit.  First thing to check is to see if this AND is with a
+      // single bit constant.
+      const APInt &AndRHSV = AndRHS->getValue();
+
+      // If there is only one bit set.
+      if (AndRHSV.isPowerOf2()) {
+        // Ok, at this point, we know that we are masking the result of the
+        // ADD down to exactly one bit.  If the constant we are adding has
+        // no bits set below this bit, then we can eliminate the ADD.
+        const APInt& AddRHS = OpRHS->getValue();
+
+        // Check to see if any bits below the one bit set in AndRHSV are set.
+        if ((AddRHS & (AndRHSV-1)) == 0) {
+          // If not, the only thing that can effect the output of the AND is
+          // the bit specified by AndRHSV.  If that bit is set, the effect of
+          // the XOR is to toggle the bit.  If it is clear, then the ADD has
+          // no effect.
+          if ((AddRHS & AndRHSV) == 0) { // Bit is not set, noop
+            TheAnd.setOperand(0, X);
+            return &TheAnd;
+          } else {
+            // Pull the XOR out of the AND.
+            Value *NewAnd = Builder->CreateAnd(X, AndRHS);
+            NewAnd->takeName(Op);
+            return BinaryOperator::CreateXor(NewAnd, AndRHS);
+          }
+        }
+      }
+    }
+    break;
+
+  case Instruction::Shl: {
+    // We know that the AND will not produce any of the bits shifted in, so if
+    // the anded constant includes them, clear them now!
+    //
+    uint32_t BitWidth = AndRHS->getType()->getBitWidth();
+    uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
+    APInt ShlMask(APInt::getHighBitsSet(BitWidth, BitWidth-OpRHSVal));
+    ConstantInt *CI = Builder->getInt(AndRHS->getValue() & ShlMask);
+
+    if (CI->getValue() == ShlMask)
+      // Masking out bits that the shift already masks.
+      return ReplaceInstUsesWith(TheAnd, Op);   // No need for the and.
+
+    if (CI != AndRHS) {                  // Reducing bits set in and.
+      TheAnd.setOperand(1, CI);
+      return &TheAnd;
+    }
+    break;
+  }
+  case Instruction::LShr: {
+    // We know that the AND will not produce any of the bits shifted in, so if
+    // the anded constant includes them, clear them now!  This only applies to
+    // unsigned shifts, because a signed shr may bring in set bits!
+    //
+    uint32_t BitWidth = AndRHS->getType()->getBitWidth();
+    uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
+    APInt ShrMask(APInt::getLowBitsSet(BitWidth, BitWidth - OpRHSVal));
+    ConstantInt *CI = Builder->getInt(AndRHS->getValue() & ShrMask);
+
+    if (CI->getValue() == ShrMask)
+      // Masking out bits that the shift already masks.
+      return ReplaceInstUsesWith(TheAnd, Op);
+
+    if (CI != AndRHS) {
+      TheAnd.setOperand(1, CI);  // Reduce bits set in and cst.
+      return &TheAnd;
+    }
+    break;
+  }
+  case Instruction::AShr:
+    // Signed shr.
+    // See if this is shifting in some sign extension, then masking it out
+    // with an and.
+    if (Op->hasOneUse()) {
+      uint32_t BitWidth = AndRHS->getType()->getBitWidth();
+      uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
+      APInt ShrMask(APInt::getLowBitsSet(BitWidth, BitWidth - OpRHSVal));
+      Constant *C = Builder->getInt(AndRHS->getValue() & ShrMask);
+      if (C == AndRHS) {          // Masking out bits shifted in.
+        // (Val ashr C1) & C2 -> (Val lshr C1) & C2
+        // Make the argument unsigned.
+        Value *ShVal = Op->getOperand(0);
+        ShVal = Builder->CreateLShr(ShVal, OpRHS, Op->getName());
+        return BinaryOperator::CreateAnd(ShVal, AndRHS, TheAnd.getName());
+      }
+    }
+    break;
+  }
+  return nullptr;
+}
+
+/// Emit a computation of: (V >= Lo && V < Hi) if Inside is true, otherwise
+/// (V < Lo || V >= Hi).  In practice, we emit the more efficient
+/// (V-Lo) \<u Hi-Lo.  This method expects that Lo <= Hi. isSigned indicates
+/// whether to treat the V, Lo and HI as signed or not. IB is the location to
+/// insert new instructions.
+Value *InstCombiner::InsertRangeTest(Value *V, Constant *Lo, Constant *Hi,
+                                     bool isSigned, bool Inside) {
+  assert(cast<ConstantInt>(ConstantExpr::getICmp((isSigned ?
+            ICmpInst::ICMP_SLE:ICmpInst::ICMP_ULE), Lo, Hi))->getZExtValue() &&
+         "Lo is not <= Hi in range emission code!");
+
+  if (Inside) {
+    if (Lo == Hi)  // Trivially false.
+      return Builder->getFalse();
+
+    // V >= Min && V < Hi --> V < Hi
+    if (cast<ConstantInt>(Lo)->isMinValue(isSigned)) {
+      ICmpInst::Predicate pred = (isSigned ?
+        ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT);
+      return Builder->CreateICmp(pred, V, Hi);
+    }
+
+    // Emit V-Lo <u Hi-Lo
+    Constant *NegLo = ConstantExpr::getNeg(Lo);
+    Value *Add = Builder->CreateAdd(V, NegLo, V->getName()+".off");
+    Constant *UpperBound = ConstantExpr::getAdd(NegLo, Hi);
+    return Builder->CreateICmpULT(Add, UpperBound);
+  }
+
+  if (Lo == Hi)  // Trivially true.
+    return Builder->getTrue();
+
+  // V < Min || V >= Hi -> V > Hi-1
+  Hi = SubOne(cast<ConstantInt>(Hi));
+  if (cast<ConstantInt>(Lo)->isMinValue(isSigned)) {
+    ICmpInst::Predicate pred = (isSigned ?
+        ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT);
+    return Builder->CreateICmp(pred, V, Hi);
+  }
+
+  // Emit V-Lo >u Hi-1-Lo
+  // Note that Hi has already had one subtracted from it, above.
+  ConstantInt *NegLo = cast<ConstantInt>(ConstantExpr::getNeg(Lo));
+  Value *Add = Builder->CreateAdd(V, NegLo, V->getName()+".off");
+  Constant *LowerBound = ConstantExpr::getAdd(NegLo, Hi);
+  return Builder->CreateICmpUGT(Add, LowerBound);
+}
+
+/// Returns true iff Val consists of one contiguous run of 1s with any number
+/// of 0s on either side.  The 1s are allowed to wrap from LSB to MSB,
+/// so 0x000FFF0, 0x0000FFFF, and 0xFF0000FF are all runs.  0x0F0F0000 is
+/// not, since all 1s are not contiguous.
+static bool isRunOfOnes(ConstantInt *Val, uint32_t &MB, uint32_t &ME) {
+  const APInt& V = Val->getValue();
+  uint32_t BitWidth = Val->getType()->getBitWidth();
+  if (!APIntOps::isShiftedMask(BitWidth, V)) return false;
+
+  // look for the first zero bit after the run of ones
+  MB = BitWidth - ((V - 1) ^ V).countLeadingZeros();
+  // look for the first non-zero bit
+  ME = V.getActiveBits();
+  return true;
+}
+
+/// This is part of an expression (LHS +/- RHS) & Mask, where isSub determines
+/// whether the operator is a sub. If we can fold one of the following xforms:
+///
+/// ((A & N) +/- B) & Mask -> (A +/- B) & Mask iff N&Mask == Mask
+/// ((A | N) +/- B) & Mask -> (A +/- B) & Mask iff N&Mask == 0
+/// ((A ^ N) +/- B) & Mask -> (A +/- B) & Mask iff N&Mask == 0
+///
+/// return (A +/- B).
+///
+Value *InstCombiner::FoldLogicalPlusAnd(Value *LHS, Value *RHS,
+                                        ConstantInt *Mask, bool isSub,
+                                        Instruction &I) {
+  Instruction *LHSI = dyn_cast<Instruction>(LHS);
+  if (!LHSI || LHSI->getNumOperands() != 2 ||
+      !isa<ConstantInt>(LHSI->getOperand(1))) return nullptr;
+
+  ConstantInt *N = cast<ConstantInt>(LHSI->getOperand(1));
+
+  switch (LHSI->getOpcode()) {
+  default: return nullptr;
+  case Instruction::And:
+    if (ConstantExpr::getAnd(N, Mask) == Mask) {
+      // If the AndRHS is a power of two minus one (0+1+), this is simple.
+      if ((Mask->getValue().countLeadingZeros() +
+           Mask->getValue().countPopulation()) ==
+          Mask->getValue().getBitWidth())
+        break;
+
+      // Otherwise, if Mask is 0+1+0+, and if B is known to have the low 0+
+      // part, we don't need any explicit masks to take them out of A.  If that
+      // is all N is, ignore it.
+      uint32_t MB = 0, ME = 0;
+      if (isRunOfOnes(Mask, MB, ME)) {  // begin/end bit of run, inclusive
+        uint32_t BitWidth = cast<IntegerType>(RHS->getType())->getBitWidth();
+        APInt Mask(APInt::getLowBitsSet(BitWidth, MB-1));
+        if (MaskedValueIsZero(RHS, Mask, 0, &I))
+          break;
+      }
+    }
+    return nullptr;
+  case Instruction::Or:
+  case Instruction::Xor:
+    // If the AndRHS is a power of two minus one (0+1+), and N&Mask == 0
+    if ((Mask->getValue().countLeadingZeros() +
+         Mask->getValue().countPopulation()) == Mask->getValue().getBitWidth()
+        && ConstantExpr::getAnd(N, Mask)->isNullValue())
+      break;
+    return nullptr;
+  }
+
+  if (isSub)
+    return Builder->CreateSub(LHSI->getOperand(0), RHS, "fold");
+  return Builder->CreateAdd(LHSI->getOperand(0), RHS, "fold");
+}
+
+/// enum for classifying (icmp eq (A & B), C) and (icmp ne (A & B), C)
+/// One of A and B is considered the mask, the other the value. This is
+/// described as the "AMask" or "BMask" part of the enum. If the enum
+/// contains only "Mask", then both A and B can be considered masks.
+/// If A is the mask, then it was proven, that (A & C) == C. This
+/// is trivial if C == A, or C == 0. If both A and C are constants, this
+/// proof is also easy.
+/// For the following explanations we assume that A is the mask.
+/// The part "AllOnes" declares, that the comparison is true only
+/// if (A & B) == A, or all bits of A are set in B.
+///   Example: (icmp eq (A & 3), 3) -> FoldMskICmp_AMask_AllOnes
+/// The part "AllZeroes" declares, that the comparison is true only
+/// if (A & B) == 0, or all bits of A are cleared in B.
+///   Example: (icmp eq (A & 3), 0) -> FoldMskICmp_Mask_AllZeroes
+/// The part "Mixed" declares, that (A & B) == C and C might or might not
+/// contain any number of one bits and zero bits.
+///   Example: (icmp eq (A & 3), 1) -> FoldMskICmp_AMask_Mixed
+/// The Part "Not" means, that in above descriptions "==" should be replaced
+/// by "!=".
+///   Example: (icmp ne (A & 3), 3) -> FoldMskICmp_AMask_NotAllOnes
+/// If the mask A contains a single bit, then the following is equivalent:
+///    (icmp eq (A & B), A) equals (icmp ne (A & B), 0)
+///    (icmp ne (A & B), A) equals (icmp eq (A & B), 0)
+enum MaskedICmpType {
+  FoldMskICmp_AMask_AllOnes           =     1,
+  FoldMskICmp_AMask_NotAllOnes        =     2,
+  FoldMskICmp_BMask_AllOnes           =     4,
+  FoldMskICmp_BMask_NotAllOnes        =     8,
+  FoldMskICmp_Mask_AllZeroes          =    16,
+  FoldMskICmp_Mask_NotAllZeroes       =    32,
+  FoldMskICmp_AMask_Mixed             =    64,
+  FoldMskICmp_AMask_NotMixed          =   128,
+  FoldMskICmp_BMask_Mixed             =   256,
+  FoldMskICmp_BMask_NotMixed          =   512
+};
+
+/// Return the set of pattern classes (from MaskedICmpType)
+/// that (icmp SCC (A & B), C) satisfies.
+static unsigned getTypeOfMaskedICmp(Value* A, Value* B, Value* C,
+                                    ICmpInst::Predicate SCC)
+{
+  ConstantInt *ACst = dyn_cast<ConstantInt>(A);
+  ConstantInt *BCst = dyn_cast<ConstantInt>(B);
+  ConstantInt *CCst = dyn_cast<ConstantInt>(C);
+  bool icmp_eq = (SCC == ICmpInst::ICMP_EQ);
+  bool icmp_abit = (ACst && !ACst->isZero() &&
+                    ACst->getValue().isPowerOf2());
+  bool icmp_bbit = (BCst && !BCst->isZero() &&
+                    BCst->getValue().isPowerOf2());
+  unsigned result = 0;
+  if (CCst && CCst->isZero()) {
+    // if C is zero, then both A and B qualify as mask
+    result |= (icmp_eq ? (FoldMskICmp_Mask_AllZeroes |
+                          FoldMskICmp_Mask_AllZeroes |
+                          FoldMskICmp_AMask_Mixed |
+                          FoldMskICmp_BMask_Mixed)
+                       : (FoldMskICmp_Mask_NotAllZeroes |
+                          FoldMskICmp_Mask_NotAllZeroes |
+                          FoldMskICmp_AMask_NotMixed |
+                          FoldMskICmp_BMask_NotMixed));
+    if (icmp_abit)
+      result |= (icmp_eq ? (FoldMskICmp_AMask_NotAllOnes |
+                            FoldMskICmp_AMask_NotMixed)
+                         : (FoldMskICmp_AMask_AllOnes |
+                            FoldMskICmp_AMask_Mixed));
+    if (icmp_bbit)
+      result |= (icmp_eq ? (FoldMskICmp_BMask_NotAllOnes |
+                            FoldMskICmp_BMask_NotMixed)
+                         : (FoldMskICmp_BMask_AllOnes |
+                            FoldMskICmp_BMask_Mixed));
+    return result;
+  }
+  if (A == C) {
+    result |= (icmp_eq ? (FoldMskICmp_AMask_AllOnes |
+                          FoldMskICmp_AMask_Mixed)
+                       : (FoldMskICmp_AMask_NotAllOnes |
+                          FoldMskICmp_AMask_NotMixed));
+    if (icmp_abit)
+      result |= (icmp_eq ? (FoldMskICmp_Mask_NotAllZeroes |
+                            FoldMskICmp_AMask_NotMixed)
+                         : (FoldMskICmp_Mask_AllZeroes |
+                            FoldMskICmp_AMask_Mixed));
+  } else if (ACst && CCst &&
+             ConstantExpr::getAnd(ACst, CCst) == CCst) {
+    result |= (icmp_eq ? FoldMskICmp_AMask_Mixed
+                       : FoldMskICmp_AMask_NotMixed);
+  }
+  if (B == C) {
+    result |= (icmp_eq ? (FoldMskICmp_BMask_AllOnes |
+                          FoldMskICmp_BMask_Mixed)
+                       : (FoldMskICmp_BMask_NotAllOnes |
+                          FoldMskICmp_BMask_NotMixed));
+    if (icmp_bbit)
+      result |= (icmp_eq ? (FoldMskICmp_Mask_NotAllZeroes |
+                            FoldMskICmp_BMask_NotMixed)
+                         : (FoldMskICmp_Mask_AllZeroes |
+                            FoldMskICmp_BMask_Mixed));
+  } else if (BCst && CCst &&
+             ConstantExpr::getAnd(BCst, CCst) == CCst) {
+    result |= (icmp_eq ? FoldMskICmp_BMask_Mixed
+                       : FoldMskICmp_BMask_NotMixed);
+  }
+  return result;
+}
+
+/// Convert an analysis of a masked ICmp into its equivalent if all boolean
+/// operations had the opposite sense. Since each "NotXXX" flag (recording !=)
+/// is adjacent to the corresponding normal flag (recording ==), this just
+/// involves swapping those bits over.
+static unsigned conjugateICmpMask(unsigned Mask) {
+  unsigned NewMask;
+  NewMask = (Mask & (FoldMskICmp_AMask_AllOnes | FoldMskICmp_BMask_AllOnes |
+                     FoldMskICmp_Mask_AllZeroes | FoldMskICmp_AMask_Mixed |
+                     FoldMskICmp_BMask_Mixed))
+            << 1;
+
+  NewMask |=
+      (Mask & (FoldMskICmp_AMask_NotAllOnes | FoldMskICmp_BMask_NotAllOnes |
+               FoldMskICmp_Mask_NotAllZeroes | FoldMskICmp_AMask_NotMixed |
+               FoldMskICmp_BMask_NotMixed))
+      >> 1;
+
+  return NewMask;
+}
+
+/// Decompose an icmp into the form ((X & Y) pred Z) if possible.
+/// The returned predicate is either == or !=. Returns false if
+/// decomposition fails.
+static bool decomposeBitTestICmp(const ICmpInst *I, ICmpInst::Predicate &Pred,
+                                 Value *&X, Value *&Y, Value *&Z) {
+  ConstantInt *C = dyn_cast<ConstantInt>(I->getOperand(1));
+  if (!C)
+    return false;
+
+  switch (I->getPredicate()) {
+  default:
+    return false;
+  case ICmpInst::ICMP_SLT:
+    // X < 0 is equivalent to (X & SignBit) != 0.
+    if (!C->isZero())
+      return false;
+    Y = ConstantInt::get(I->getContext(), APInt::getSignBit(C->getBitWidth()));
+    Pred = ICmpInst::ICMP_NE;
+    break;
+  case ICmpInst::ICMP_SGT:
+    // X > -1 is equivalent to (X & SignBit) == 0.
+    if (!C->isAllOnesValue())
+      return false;
+    Y = ConstantInt::get(I->getContext(), APInt::getSignBit(C->getBitWidth()));
+    Pred = ICmpInst::ICMP_EQ;
+    break;
+  case ICmpInst::ICMP_ULT:
+    // X <u 2^n is equivalent to (X & ~(2^n-1)) == 0.
+    if (!C->getValue().isPowerOf2())
+      return false;
+    Y = ConstantInt::get(I->getContext(), -C->getValue());
+    Pred = ICmpInst::ICMP_EQ;
+    break;
+  case ICmpInst::ICMP_UGT:
+    // X >u 2^n-1 is equivalent to (X & ~(2^n-1)) != 0.
+    if (!(C->getValue() + 1).isPowerOf2())
+      return false;
+    Y = ConstantInt::get(I->getContext(), ~C->getValue());
+    Pred = ICmpInst::ICMP_NE;
+    break;
+  }
+
+  X = I->getOperand(0);
+  Z = ConstantInt::getNullValue(C->getType());
+  return true;
+}
+
+/// Handle (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E)
+/// Return the set of pattern classes (from MaskedICmpType)
+/// that both LHS and RHS satisfy.
+static unsigned foldLogOpOfMaskedICmpsHelper(Value*& A,
+                                             Value*& B, Value*& C,
+                                             Value*& D, Value*& E,
+                                             ICmpInst *LHS, ICmpInst *RHS,
+                                             ICmpInst::Predicate &LHSCC,
+                                             ICmpInst::Predicate &RHSCC) {
+  if (LHS->getOperand(0)->getType() != RHS->getOperand(0)->getType()) return 0;
+  // vectors are not (yet?) supported
+  if (LHS->getOperand(0)->getType()->isVectorTy()) return 0;
+
+  // Here comes the tricky part:
+  // LHS might be of the form L11 & L12 == X, X == L21 & L22,
+  // and L11 & L12 == L21 & L22. The same goes for RHS.
+  // Now we must find those components L** and R**, that are equal, so
+  // that we can extract the parameters A, B, C, D, and E for the canonical
+  // above.
+  Value *L1 = LHS->getOperand(0);
+  Value *L2 = LHS->getOperand(1);
+  Value *L11,*L12,*L21,*L22;
+  // Check whether the icmp can be decomposed into a bit test.
+  if (decomposeBitTestICmp(LHS, LHSCC, L11, L12, L2)) {
+    L21 = L22 = L1 = nullptr;
+  } else {
+    // Look for ANDs in the LHS icmp.
+    if (!L1->getType()->isIntegerTy()) {
+      // You can icmp pointers, for example. They really aren't masks.
+      L11 = L12 = nullptr;
+    } else if (!match(L1, m_And(m_Value(L11), m_Value(L12)))) {
+      // Any icmp can be viewed as being trivially masked; if it allows us to
+      // remove one, it's worth it.
+      L11 = L1;
+      L12 = Constant::getAllOnesValue(L1->getType());
+    }
+
+    if (!L2->getType()->isIntegerTy()) {
+      // You can icmp pointers, for example. They really aren't masks.
+      L21 = L22 = nullptr;
+    } else if (!match(L2, m_And(m_Value(L21), m_Value(L22)))) {
+      L21 = L2;
+      L22 = Constant::getAllOnesValue(L2->getType());
+    }
+  }
+
+  // Bail if LHS was a icmp that can't be decomposed into an equality.
+  if (!ICmpInst::isEquality(LHSCC))
+    return 0;
+
+  Value *R1 = RHS->getOperand(0);
+  Value *R2 = RHS->getOperand(1);
+  Value *R11,*R12;
+  bool ok = false;
+  if (decomposeBitTestICmp(RHS, RHSCC, R11, R12, R2)) {
+    if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
+      A = R11; D = R12;
+    } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
+      A = R12; D = R11;
+    } else {
+      return 0;
+    }
+    E = R2; R1 = nullptr; ok = true;
+  } else if (R1->getType()->isIntegerTy()) {
+    if (!match(R1, m_And(m_Value(R11), m_Value(R12)))) {
+      // As before, model no mask as a trivial mask if it'll let us do an
+      // optimization.
+      R11 = R1;
+      R12 = Constant::getAllOnesValue(R1->getType());
+    }
+
+    if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
+      A = R11; D = R12; E = R2; ok = true;
+    } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
+      A = R12; D = R11; E = R2; ok = true;
+    }
+  }
+
+  // Bail if RHS was a icmp that can't be decomposed into an equality.
+  if (!ICmpInst::isEquality(RHSCC))
+    return 0;
+
+  // Look for ANDs in on the right side of the RHS icmp.
+  if (!ok && R2->getType()->isIntegerTy()) {
+    if (!match(R2, m_And(m_Value(R11), m_Value(R12)))) {
+      R11 = R2;
+      R12 = Constant::getAllOnesValue(R2->getType());
+    }
+
+    if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
+      A = R11; D = R12; E = R1; ok = true;
+    } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
+      A = R12; D = R11; E = R1; ok = true;
+    } else {
+      return 0;
+    }
+  }
+  if (!ok)
+    return 0;
+
+  if (L11 == A) {
+    B = L12; C = L2;
+  } else if (L12 == A) {
+    B = L11; C = L2;
+  } else if (L21 == A) {
+    B = L22; C = L1;
+  } else if (L22 == A) {
+    B = L21; C = L1;
+  }
+
+  unsigned left_type = getTypeOfMaskedICmp(A, B, C, LHSCC);
+  unsigned right_type = getTypeOfMaskedICmp(A, D, E, RHSCC);
+  return left_type & right_type;
+}
+
+/// Try to fold (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E)
+/// into a single (icmp(A & X) ==/!= Y).
+static Value *foldLogOpOfMaskedICmps(ICmpInst *LHS, ICmpInst *RHS, bool IsAnd,
+                                     llvm::InstCombiner::BuilderTy *Builder) {
+  Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr, *E = nullptr;
+  ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate();
+  unsigned mask = foldLogOpOfMaskedICmpsHelper(A, B, C, D, E, LHS, RHS,
+                                               LHSCC, RHSCC);
+  if (mask == 0) return nullptr;
+  assert(ICmpInst::isEquality(LHSCC) && ICmpInst::isEquality(RHSCC) &&
+         "foldLogOpOfMaskedICmpsHelper must return an equality predicate.");
+
+  // In full generality:
+  //     (icmp (A & B) Op C) | (icmp (A & D) Op E)
+  // ==  ![ (icmp (A & B) !Op C) & (icmp (A & D) !Op E) ]
+  //
+  // If the latter can be converted into (icmp (A & X) Op Y) then the former is
+  // equivalent to (icmp (A & X) !Op Y).
+  //
+  // Therefore, we can pretend for the rest of this function that we're dealing
+  // with the conjunction, provided we flip the sense of any comparisons (both
+  // input and output).
+
+  // In most cases we're going to produce an EQ for the "&&" case.
+  ICmpInst::Predicate NEWCC = IsAnd ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE;
+  if (!IsAnd) {
+    // Convert the masking analysis into its equivalent with negated
+    // comparisons.
+    mask = conjugateICmpMask(mask);
+  }
+
+  if (mask & FoldMskICmp_Mask_AllZeroes) {
+    // (icmp eq (A & B), 0) & (icmp eq (A & D), 0)
+    // -> (icmp eq (A & (B|D)), 0)
+    Value *newOr = Builder->CreateOr(B, D);
+    Value *newAnd = Builder->CreateAnd(A, newOr);
+    // we can't use C as zero, because we might actually handle
+    //   (icmp ne (A & B), B) & (icmp ne (A & D), D)
+    // with B and D, having a single bit set
+    Value *zero = Constant::getNullValue(A->getType());
+    return Builder->CreateICmp(NEWCC, newAnd, zero);
+  }
+  if (mask & FoldMskICmp_BMask_AllOnes) {
+    // (icmp eq (A & B), B) & (icmp eq (A & D), D)
+    // -> (icmp eq (A & (B|D)), (B|D))
+    Value *newOr = Builder->CreateOr(B, D);
+    Value *newAnd = Builder->CreateAnd(A, newOr);
+    return Builder->CreateICmp(NEWCC, newAnd, newOr);
+  }
+  if (mask & FoldMskICmp_AMask_AllOnes) {
+    // (icmp eq (A & B), A) & (icmp eq (A & D), A)
+    // -> (icmp eq (A & (B&D)), A)
+    Value *newAnd1 = Builder->CreateAnd(B, D);
+    Value *newAnd = Builder->CreateAnd(A, newAnd1);
+    return Builder->CreateICmp(NEWCC, newAnd, A);
+  }
+
+  // Remaining cases assume at least that B and D are constant, and depend on
+  // their actual values. This isn't strictly, necessary, just a "handle the
+  // easy cases for now" decision.
+  ConstantInt *BCst = dyn_cast<ConstantInt>(B);
+  if (!BCst) return nullptr;
+  ConstantInt *DCst = dyn_cast<ConstantInt>(D);
+  if (!DCst) return nullptr;
+
+  if (mask & (FoldMskICmp_Mask_NotAllZeroes | FoldMskICmp_BMask_NotAllOnes)) {
+    // (icmp ne (A & B), 0) & (icmp ne (A & D), 0) and
+    // (icmp ne (A & B), B) & (icmp ne (A & D), D)
+    //     -> (icmp ne (A & B), 0) or (icmp ne (A & D), 0)
+    // Only valid if one of the masks is a superset of the other (check "B&D" is
+    // the same as either B or D).
+    APInt NewMask = BCst->getValue() & DCst->getValue();
+
+    if (NewMask == BCst->getValue())
+      return LHS;
+    else if (NewMask == DCst->getValue())
+      return RHS;
+  }
+  if (mask & FoldMskICmp_AMask_NotAllOnes) {
+    // (icmp ne (A & B), B) & (icmp ne (A & D), D)
+    //     -> (icmp ne (A & B), A) or (icmp ne (A & D), A)
+    // Only valid if one of the masks is a superset of the other (check "B|D" is
+    // the same as either B or D).
+    APInt NewMask = BCst->getValue() | DCst->getValue();
+
+    if (NewMask == BCst->getValue())
+      return LHS;
+    else if (NewMask == DCst->getValue())
+      return RHS;
+  }
+  if (mask & FoldMskICmp_BMask_Mixed) {
+    // (icmp eq (A & B), C) & (icmp eq (A & D), E)
+    // We already know that B & C == C && D & E == E.
+    // If we can prove that (B & D) & (C ^ E) == 0, that is, the bits of
+    // C and E, which are shared by both the mask B and the mask D, don't
+    // contradict, then we can transform to
+    // -> (icmp eq (A & (B|D)), (C|E))
+    // Currently, we only handle the case of B, C, D, and E being constant.
+    // we can't simply use C and E, because we might actually handle
+    //   (icmp ne (A & B), B) & (icmp eq (A & D), D)
+    // with B and D, having a single bit set
+    ConstantInt *CCst = dyn_cast<ConstantInt>(C);
+    if (!CCst) return nullptr;
+    ConstantInt *ECst = dyn_cast<ConstantInt>(E);
+    if (!ECst) return nullptr;
+    if (LHSCC != NEWCC)
+      CCst = cast<ConstantInt>(ConstantExpr::getXor(BCst, CCst));
+    if (RHSCC != NEWCC)
+      ECst = cast<ConstantInt>(ConstantExpr::getXor(DCst, ECst));
+    // if there is a conflict we should actually return a false for the
+    // whole construct
+    if (((BCst->getValue() & DCst->getValue()) &
+         (CCst->getValue() ^ ECst->getValue())) != 0)
+      return ConstantInt::get(LHS->getType(), !IsAnd);
+    Value *newOr1 = Builder->CreateOr(B, D);
+    Value *newOr2 = ConstantExpr::getOr(CCst, ECst);
+    Value *newAnd = Builder->CreateAnd(A, newOr1);
+    return Builder->CreateICmp(NEWCC, newAnd, newOr2);
+  }
+  return nullptr;
+}
+
+/// Try to fold a signed range checked with lower bound 0 to an unsigned icmp.
+/// Example: (icmp sge x, 0) & (icmp slt x, n) --> icmp ult x, n
+/// If \p Inverted is true then the check is for the inverted range, e.g.
+/// (icmp slt x, 0) | (icmp sgt x, n) --> icmp ugt x, n
+Value *InstCombiner::simplifyRangeCheck(ICmpInst *Cmp0, ICmpInst *Cmp1,
+                                        bool Inverted) {
+  // Check the lower range comparison, e.g. x >= 0
+  // InstCombine already ensured that if there is a constant it's on the RHS.
+  ConstantInt *RangeStart = dyn_cast<ConstantInt>(Cmp0->getOperand(1));
+  if (!RangeStart)
+    return nullptr;
+
+  ICmpInst::Predicate Pred0 = (Inverted ? Cmp0->getInversePredicate() :
+                               Cmp0->getPredicate());
+
+  // Accept x > -1 or x >= 0 (after potentially inverting the predicate).
+  if (!((Pred0 == ICmpInst::ICMP_SGT && RangeStart->isMinusOne()) ||
+        (Pred0 == ICmpInst::ICMP_SGE && RangeStart->isZero())))
+    return nullptr;
+
+  ICmpInst::Predicate Pred1 = (Inverted ? Cmp1->getInversePredicate() :
+                               Cmp1->getPredicate());
+
+  Value *Input = Cmp0->getOperand(0);
+  Value *RangeEnd;
+  if (Cmp1->getOperand(0) == Input) {
+    // For the upper range compare we have: icmp x, n
+    RangeEnd = Cmp1->getOperand(1);
+  } else if (Cmp1->getOperand(1) == Input) {
+    // For the upper range compare we have: icmp n, x
+    RangeEnd = Cmp1->getOperand(0);
+    Pred1 = ICmpInst::getSwappedPredicate(Pred1);
+  } else {
+    return nullptr;
+  }
+
+  // Check the upper range comparison, e.g. x < n
+  ICmpInst::Predicate NewPred;
+  switch (Pred1) {
+    case ICmpInst::ICMP_SLT: NewPred = ICmpInst::ICMP_ULT; break;
+    case ICmpInst::ICMP_SLE: NewPred = ICmpInst::ICMP_ULE; break;
+    default: return nullptr;
+  }
+
+  // This simplification is only valid if the upper range is not negative.
+  bool IsNegative, IsNotNegative;
+  ComputeSignBit(RangeEnd, IsNotNegative, IsNegative, /*Depth=*/0, Cmp1);
+  if (!IsNotNegative)
+    return nullptr;
+
+  if (Inverted)
+    NewPred = ICmpInst::getInversePredicate(NewPred);
+
+  return Builder->CreateICmp(NewPred, Input, RangeEnd);
+}
+
+/// Fold (icmp)&(icmp) if possible.
+Value *InstCombiner::FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
+  ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate();
+
+  // (icmp1 A, B) & (icmp2 A, B) --> (icmp3 A, B)
+  if (PredicatesFoldable(LHSCC, RHSCC)) {
+    if (LHS->getOperand(0) == RHS->getOperand(1) &&
+        LHS->getOperand(1) == RHS->getOperand(0))
+      LHS->swapOperands();
+    if (LHS->getOperand(0) == RHS->getOperand(0) &&
+        LHS->getOperand(1) == RHS->getOperand(1)) {
+      Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
+      unsigned Code = getICmpCode(LHS) & getICmpCode(RHS);
+      bool isSigned = LHS->isSigned() || RHS->isSigned();
+      return getNewICmpValue(isSigned, Code, Op0, Op1, Builder);
+    }
+  }
+
+  // handle (roughly):  (icmp eq (A & B), C) & (icmp eq (A & D), E)
+  if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, true, Builder))
+    return V;
+
+  // E.g. (icmp sge x, 0) & (icmp slt x, n) --> icmp ult x, n
+  if (Value *V = simplifyRangeCheck(LHS, RHS, /*Inverted=*/false))
+    return V;
+
+  // E.g. (icmp slt x, n) & (icmp sge x, 0) --> icmp ult x, n
+  if (Value *V = simplifyRangeCheck(RHS, LHS, /*Inverted=*/false))
+    return V;
+
+  // This only handles icmp of constants: (icmp1 A, C1) & (icmp2 B, C2).
+  Value *Val = LHS->getOperand(0), *Val2 = RHS->getOperand(0);
+  ConstantInt *LHSCst = dyn_cast<ConstantInt>(LHS->getOperand(1));
+  ConstantInt *RHSCst = dyn_cast<ConstantInt>(RHS->getOperand(1));
+  if (!LHSCst || !RHSCst) return nullptr;
+
+  if (LHSCst == RHSCst && LHSCC == RHSCC) {
+    // (icmp ult A, C) & (icmp ult B, C) --> (icmp ult (A|B), C)
+    // where C is a power of 2
+    if (LHSCC == ICmpInst::ICMP_ULT &&
+        LHSCst->getValue().isPowerOf2()) {
+      Value *NewOr = Builder->CreateOr(Val, Val2);
+      return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
+    }
+
+    // (icmp eq A, 0) & (icmp eq B, 0) --> (icmp eq (A|B), 0)
+    if (LHSCC == ICmpInst::ICMP_EQ && LHSCst->isZero()) {
+      Value *NewOr = Builder->CreateOr(Val, Val2);
+      return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
+    }
+  }
+
+  // (trunc x) == C1 & (and x, CA) == C2 -> (and x, CA|CMAX) == C1|C2
+  // where CMAX is the all ones value for the truncated type,
+  // iff the lower bits of C2 and CA are zero.
+  if (LHSCC == ICmpInst::ICMP_EQ && LHSCC == RHSCC &&
+      LHS->hasOneUse() && RHS->hasOneUse()) {
+    Value *V;
+    ConstantInt *AndCst, *SmallCst = nullptr, *BigCst = nullptr;
+
+    // (trunc x) == C1 & (and x, CA) == C2
+    // (and x, CA) == C2 & (trunc x) == C1
+    if (match(Val2, m_Trunc(m_Value(V))) &&
+        match(Val, m_And(m_Specific(V), m_ConstantInt(AndCst)))) {
+      SmallCst = RHSCst;
+      BigCst = LHSCst;
+    } else if (match(Val, m_Trunc(m_Value(V))) &&
+               match(Val2, m_And(m_Specific(V), m_ConstantInt(AndCst)))) {
+      SmallCst = LHSCst;
+      BigCst = RHSCst;
+    }
+
+    if (SmallCst && BigCst) {
+      unsigned BigBitSize = BigCst->getType()->getBitWidth();
+      unsigned SmallBitSize = SmallCst->getType()->getBitWidth();
+
+      // Check that the low bits are zero.
+      APInt Low = APInt::getLowBitsSet(BigBitSize, SmallBitSize);
+      if ((Low & AndCst->getValue()) == 0 && (Low & BigCst->getValue()) == 0) {
+        Value *NewAnd = Builder->CreateAnd(V, Low | AndCst->getValue());
+        APInt N = SmallCst->getValue().zext(BigBitSize) | BigCst->getValue();
+        Value *NewVal = ConstantInt::get(AndCst->getType()->getContext(), N);
+        return Builder->CreateICmp(LHSCC, NewAnd, NewVal);
+      }
+    }
+  }
+
+  // From here on, we only handle:
+  //    (icmp1 A, C1) & (icmp2 A, C2) --> something simpler.
+  if (Val != Val2) return nullptr;
+
+  // ICMP_[US][GL]E X, CST is folded to ICMP_[US][GL]T elsewhere.
+  if (LHSCC == ICmpInst::ICMP_UGE || LHSCC == ICmpInst::ICMP_ULE ||
+      RHSCC == ICmpInst::ICMP_UGE || RHSCC == ICmpInst::ICMP_ULE ||
+      LHSCC == ICmpInst::ICMP_SGE || LHSCC == ICmpInst::ICMP_SLE ||
+      RHSCC == ICmpInst::ICMP_SGE || RHSCC == ICmpInst::ICMP_SLE)
+    return nullptr;
+
+  // Make a constant range that's the intersection of the two icmp ranges.
+  // If the intersection is empty, we know that the result is false.
+  ConstantRange LHSRange =
+      ConstantRange::makeAllowedICmpRegion(LHSCC, LHSCst->getValue());
+  ConstantRange RHSRange =
+      ConstantRange::makeAllowedICmpRegion(RHSCC, RHSCst->getValue());
+
+  if (LHSRange.intersectWith(RHSRange).isEmptySet())
+    return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
+
+  // We can't fold (ugt x, C) & (sgt x, C2).
+  if (!PredicatesFoldable(LHSCC, RHSCC))
+    return nullptr;
+
+  // Ensure that the larger constant is on the RHS.
+  bool ShouldSwap;
+  if (CmpInst::isSigned(LHSCC) ||
+      (ICmpInst::isEquality(LHSCC) &&
+       CmpInst::isSigned(RHSCC)))
+    ShouldSwap = LHSCst->getValue().sgt(RHSCst->getValue());
+  else
+    ShouldSwap = LHSCst->getValue().ugt(RHSCst->getValue());
+
+  if (ShouldSwap) {
+    std::swap(LHS, RHS);
+    std::swap(LHSCst, RHSCst);
+    std::swap(LHSCC, RHSCC);
+  }
+
+  // At this point, we know we have two icmp instructions
+  // comparing a value against two constants and and'ing the result
+  // together.  Because of the above check, we know that we only have
+  // icmp eq, icmp ne, icmp [su]lt, and icmp [SU]gt here. We also know
+  // (from the icmp folding check above), that the two constants
+  // are not equal and that the larger constant is on the RHS
+  assert(LHSCst != RHSCst && "Compares not folded above?");
+
+  switch (LHSCC) {
+  default: llvm_unreachable("Unknown integer condition code!");
+  case ICmpInst::ICMP_EQ:
+    switch (RHSCC) {
+    default: llvm_unreachable("Unknown integer condition code!");
+    case ICmpInst::ICMP_NE:         // (X == 13 & X != 15) -> X == 13
+    case ICmpInst::ICMP_ULT:        // (X == 13 & X <  15) -> X == 13
+    case ICmpInst::ICMP_SLT:        // (X == 13 & X <  15) -> X == 13
+      return LHS;
+    }
+  case ICmpInst::ICMP_NE:
+    switch (RHSCC) {
+    default: llvm_unreachable("Unknown integer condition code!");
+    case ICmpInst::ICMP_ULT:
+      if (LHSCst == SubOne(RHSCst)) // (X != 13 & X u< 14) -> X < 13
+        return Builder->CreateICmpULT(Val, LHSCst);
+      if (LHSCst->isNullValue())    // (X !=  0 & X u< 14) -> X-1 u< 13
+        return InsertRangeTest(Val, AddOne(LHSCst), RHSCst, false, true);
+      break;                        // (X != 13 & X u< 15) -> no change
+    case ICmpInst::ICMP_SLT:
+      if (LHSCst == SubOne(RHSCst)) // (X != 13 & X s< 14) -> X < 13
+        return Builder->CreateICmpSLT(Val, LHSCst);
+      break;                        // (X != 13 & X s< 15) -> no change
+    case ICmpInst::ICMP_EQ:         // (X != 13 & X == 15) -> X == 15
+    case ICmpInst::ICMP_UGT:        // (X != 13 & X u> 15) -> X u> 15
+    case ICmpInst::ICMP_SGT:        // (X != 13 & X s> 15) -> X s> 15
+      return RHS;
+    case ICmpInst::ICMP_NE:
+      // Special case to get the ordering right when the values wrap around
+      // zero.
+      if (LHSCst->getValue() == 0 && RHSCst->getValue().isAllOnesValue())
+        std::swap(LHSCst, RHSCst);
+      if (LHSCst == SubOne(RHSCst)){// (X != 13 & X != 14) -> X-13 >u 1
+        Constant *AddCST = ConstantExpr::getNeg(LHSCst);
+        Value *Add = Builder->CreateAdd(Val, AddCST, Val->getName()+".off");
+        return Builder->CreateICmpUGT(Add, ConstantInt::get(Add->getType(), 1),
+                                      Val->getName()+".cmp");
+      }
+      break;                        // (X != 13 & X != 15) -> no change
+    }
+    break;
+  case ICmpInst::ICMP_ULT:
+    switch (RHSCC) {
+    default: llvm_unreachable("Unknown integer condition code!");
+    case ICmpInst::ICMP_EQ:         // (X u< 13 & X == 15) -> false
+    case ICmpInst::ICMP_UGT:        // (X u< 13 & X u> 15) -> false
+      return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
+    case ICmpInst::ICMP_SGT:        // (X u< 13 & X s> 15) -> no change
+      break;
+    case ICmpInst::ICMP_NE:         // (X u< 13 & X != 15) -> X u< 13
+    case ICmpInst::ICMP_ULT:        // (X u< 13 & X u< 15) -> X u< 13
+      return LHS;
+    case ICmpInst::ICMP_SLT:        // (X u< 13 & X s< 15) -> no change
+      break;
+    }
+    break;
+  case ICmpInst::ICMP_SLT:
+    switch (RHSCC) {
+    default: llvm_unreachable("Unknown integer condition code!");
+    case ICmpInst::ICMP_UGT:        // (X s< 13 & X u> 15) -> no change
+      break;
+    case ICmpInst::ICMP_NE:         // (X s< 13 & X != 15) -> X < 13
+    case ICmpInst::ICMP_SLT:        // (X s< 13 & X s< 15) -> X < 13
+      return LHS;
+    case ICmpInst::ICMP_ULT:        // (X s< 13 & X u< 15) -> no change
+      break;
+    }
+    break;
+  case ICmpInst::ICMP_UGT:
+    switch (RHSCC) {
+    default: llvm_unreachable("Unknown integer condition code!");
+    case ICmpInst::ICMP_EQ:         // (X u> 13 & X == 15) -> X == 15
+    case ICmpInst::ICMP_UGT:        // (X u> 13 & X u> 15) -> X u> 15
+      return RHS;
+    case ICmpInst::ICMP_SGT:        // (X u> 13 & X s> 15) -> no change
+      break;
+    case ICmpInst::ICMP_NE:
+      if (RHSCst == AddOne(LHSCst)) // (X u> 13 & X != 14) -> X u> 14
+        return Builder->CreateICmp(LHSCC, Val, RHSCst);
+      break;                        // (X u> 13 & X != 15) -> no change
+    case ICmpInst::ICMP_ULT:        // (X u> 13 & X u< 15) -> (X-14) <u 1
+      return InsertRangeTest(Val, AddOne(LHSCst), RHSCst, false, true);
+    case ICmpInst::ICMP_SLT:        // (X u> 13 & X s< 15) -> no change
+      break;
+    }
+    break;
+  case ICmpInst::ICMP_SGT:
+    switch (RHSCC) {
+    default: llvm_unreachable("Unknown integer condition code!");
+    case ICmpInst::ICMP_EQ:         // (X s> 13 & X == 15) -> X == 15
+    case ICmpInst::ICMP_SGT:        // (X s> 13 & X s> 15) -> X s> 15
+      return RHS;
+    case ICmpInst::ICMP_UGT:        // (X s> 13 & X u> 15) -> no change
+      break;
+    case ICmpInst::ICMP_NE:
+      if (RHSCst == AddOne(LHSCst)) // (X s> 13 & X != 14) -> X s> 14
+        return Builder->CreateICmp(LHSCC, Val, RHSCst);
+      break;                        // (X s> 13 & X != 15) -> no change
+    case ICmpInst::ICMP_SLT:        // (X s> 13 & X s< 15) -> (X-14) s< 1
+      return InsertRangeTest(Val, AddOne(LHSCst), RHSCst, true, true);
+    case ICmpInst::ICMP_ULT:        // (X s> 13 & X u< 15) -> no change
+      break;
+    }
+    break;
+  }
+
+  return nullptr;
+}
+
+/// Optimize (fcmp)&(fcmp).  NOTE: Unlike the rest of instcombine, this returns
+/// a Value which should already be inserted into the function.
+Value *InstCombiner::FoldAndOfFCmps(FCmpInst *LHS, FCmpInst *RHS) {
+  if (LHS->getPredicate() == FCmpInst::FCMP_ORD &&
+      RHS->getPredicate() == FCmpInst::FCMP_ORD) {
+    if (LHS->getOperand(0)->getType() != RHS->getOperand(0)->getType())
+      return nullptr;
+
+    // (fcmp ord x, c) & (fcmp ord y, c)  -> (fcmp ord x, y)
+    if (ConstantFP *LHSC = dyn_cast<ConstantFP>(LHS->getOperand(1)))
+      if (ConstantFP *RHSC = dyn_cast<ConstantFP>(RHS->getOperand(1))) {
+        // If either of the constants are nans, then the whole thing returns
+        // false.
+        if (LHSC->getValueAPF().isNaN() || RHSC->getValueAPF().isNaN())
+          return Builder->getFalse();
+        return Builder->CreateFCmpORD(LHS->getOperand(0), RHS->getOperand(0));
+      }
+
+    // Handle vector zeros.  This occurs because the canonical form of
+    // "fcmp ord x,x" is "fcmp ord x, 0".
+    if (isa<ConstantAggregateZero>(LHS->getOperand(1)) &&
+        isa<ConstantAggregateZero>(RHS->getOperand(1)))
+      return Builder->CreateFCmpORD(LHS->getOperand(0), RHS->getOperand(0));
+    return nullptr;
+  }
+
+  Value *Op0LHS = LHS->getOperand(0), *Op0RHS = LHS->getOperand(1);
+  Value *Op1LHS = RHS->getOperand(0), *Op1RHS = RHS->getOperand(1);
+  FCmpInst::Predicate Op0CC = LHS->getPredicate(), Op1CC = RHS->getPredicate();
+
+
+  if (Op0LHS == Op1RHS && Op0RHS == Op1LHS) {
+    // Swap RHS operands to match LHS.
+    Op1CC = FCmpInst::getSwappedPredicate(Op1CC);
+    std::swap(Op1LHS, Op1RHS);
+  }
+
+  if (Op0LHS == Op1LHS && Op0RHS == Op1RHS) {
+    // Simplify (fcmp cc0 x, y) & (fcmp cc1 x, y).
+    if (Op0CC == Op1CC)
+      return Builder->CreateFCmp((FCmpInst::Predicate)Op0CC, Op0LHS, Op0RHS);
+    if (Op0CC == FCmpInst::FCMP_FALSE || Op1CC == FCmpInst::FCMP_FALSE)
+      return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
+    if (Op0CC == FCmpInst::FCMP_TRUE)
+      return RHS;
+    if (Op1CC == FCmpInst::FCMP_TRUE)
+      return LHS;
+
+    bool Op0Ordered;
+    bool Op1Ordered;
+    unsigned Op0Pred = getFCmpCode(Op0CC, Op0Ordered);
+    unsigned Op1Pred = getFCmpCode(Op1CC, Op1Ordered);
+    // uno && ord -> false
+    if (Op0Pred == 0 && Op1Pred == 0 && Op0Ordered != Op1Ordered)
+        return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
+    if (Op1Pred == 0) {
+      std::swap(LHS, RHS);
+      std::swap(Op0Pred, Op1Pred);
+      std::swap(Op0Ordered, Op1Ordered);
+    }
+    if (Op0Pred == 0) {
+      // uno && ueq -> uno && (uno || eq) -> uno
+      // ord && olt -> ord && (ord && lt) -> olt
+      if (!Op0Ordered && (Op0Ordered == Op1Ordered))
+        return LHS;
+      if (Op0Ordered && (Op0Ordered == Op1Ordered))
+        return RHS;
+
+      // uno && oeq -> uno && (ord && eq) -> false
+      if (!Op0Ordered)
+        return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
+      // ord && ueq -> ord && (uno || eq) -> oeq
+      return getFCmpValue(true, Op1Pred, Op0LHS, Op0RHS, Builder);
+    }
+  }
+
+  return nullptr;
+}
+
+/// Match De Morgan's Laws:
+/// (~A & ~B) == (~(A | B))
+/// (~A | ~B) == (~(A & B))
+static Instruction *matchDeMorgansLaws(BinaryOperator &I,
+                                       InstCombiner::BuilderTy *Builder) {
+  auto Opcode = I.getOpcode();
+  assert((Opcode == Instruction::And || Opcode == Instruction::Or) &&
+         "Trying to match De Morgan's Laws with something other than and/or");
+  // Flip the logic operation.
+  if (Opcode == Instruction::And)
+    Opcode = Instruction::Or;
+  else
+    Opcode = Instruction::And;
+
+  Value *Op0 = I.getOperand(0);
+  Value *Op1 = I.getOperand(1);
+  // TODO: Use pattern matchers instead of dyn_cast.
+  if (Value *Op0NotVal = dyn_castNotVal(Op0))
+    if (Value *Op1NotVal = dyn_castNotVal(Op1))
+      if (Op0->hasOneUse() && Op1->hasOneUse()) {
+        Value *LogicOp = Builder->CreateBinOp(Opcode, Op0NotVal, Op1NotVal,
+                                              I.getName() + ".demorgan");
+        return BinaryOperator::CreateNot(LogicOp);
+      }
+
+  // De Morgan's Law in disguise:
+  // (zext(bool A) ^ 1) & (zext(bool B) ^ 1) -> zext(~(A | B))
+  // (zext(bool A) ^ 1) | (zext(bool B) ^ 1) -> zext(~(A & B))
+  Value *A = nullptr;
+  Value *B = nullptr;
+  ConstantInt *C1 = nullptr;
+  if (match(Op0, m_OneUse(m_Xor(m_ZExt(m_Value(A)), m_ConstantInt(C1)))) &&
+      match(Op1, m_OneUse(m_Xor(m_ZExt(m_Value(B)), m_Specific(C1))))) {
+    // TODO: This check could be loosened to handle different type sizes.
+    // Alternatively, we could fix the definition of m_Not to recognize a not
+    // operation hidden by a zext?
+    if (A->getType()->isIntegerTy(1) && B->getType()->isIntegerTy(1) &&
+        C1->isOne()) {
+      Value *LogicOp = Builder->CreateBinOp(Opcode, A, B,
+                                            I.getName() + ".demorgan");
+      Value *Not = Builder->CreateNot(LogicOp);
+      return CastInst::CreateZExtOrBitCast(Not, I.getType());
+    }
+  }
+
+  return nullptr;
+}
+
+Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
+  bool Changed = SimplifyAssociativeOrCommutative(I);
+  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+
+  if (Value *V = SimplifyVectorOp(I))
+    return ReplaceInstUsesWith(I, V);
+
+  if (Value *V = SimplifyAndInst(Op0, Op1, DL, TLI, DT, AC))
+    return ReplaceInstUsesWith(I, V);
+
+  // (A|B)&(A|C) -> A|(B&C) etc
+  if (Value *V = SimplifyUsingDistributiveLaws(I))
+    return ReplaceInstUsesWith(I, V);
+
+  // See if we can simplify any instructions used by the instruction whose sole
+  // purpose is to compute bits we don't care about.
+  if (SimplifyDemandedInstructionBits(I))
+    return &I;
+
+  if (Value *V = SimplifyBSwap(I))
+    return ReplaceInstUsesWith(I, V);
+
+  if (ConstantInt *AndRHS = dyn_cast<ConstantInt>(Op1)) {
+    const APInt &AndRHSMask = AndRHS->getValue();
+
+    // Optimize a variety of ((val OP C1) & C2) combinations...
+    if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
+      Value *Op0LHS = Op0I->getOperand(0);
+      Value *Op0RHS = Op0I->getOperand(1);
+      switch (Op0I->getOpcode()) {
+      default: break;
+      case Instruction::Xor:
+      case Instruction::Or: {
+        // If the mask is only needed on one incoming arm, push it up.
+        if (!Op0I->hasOneUse()) break;
+
+        APInt NotAndRHS(~AndRHSMask);
+        if (MaskedValueIsZero(Op0LHS, NotAndRHS, 0, &I)) {
+          // Not masking anything out for the LHS, move to RHS.
+          Value *NewRHS = Builder->CreateAnd(Op0RHS, AndRHS,
+                                             Op0RHS->getName()+".masked");
+          return BinaryOperator::Create(Op0I->getOpcode(), Op0LHS, NewRHS);
+        }
+        if (!isa<Constant>(Op0RHS) &&
+            MaskedValueIsZero(Op0RHS, NotAndRHS, 0, &I)) {
+          // Not masking anything out for the RHS, move to LHS.
+          Value *NewLHS = Builder->CreateAnd(Op0LHS, AndRHS,
+                                             Op0LHS->getName()+".masked");
+          return BinaryOperator::Create(Op0I->getOpcode(), NewLHS, Op0RHS);
+        }
+
+        break;
+      }
+      case Instruction::Add:
+        // ((A & N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == AndRHS.
+        // ((A | N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == 0
+        // ((A ^ N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == 0
+        if (Value *V = FoldLogicalPlusAnd(Op0LHS, Op0RHS, AndRHS, false, I))
+          return BinaryOperator::CreateAnd(V, AndRHS);
+        if (Value *V = FoldLogicalPlusAnd(Op0RHS, Op0LHS, AndRHS, false, I))
+          return BinaryOperator::CreateAnd(V, AndRHS);  // Add commutes
+        break;
+
+      case Instruction::Sub:
+        // ((A & N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == AndRHS.
+        // ((A | N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == 0
+        // ((A ^ N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == 0
+        if (Value *V = FoldLogicalPlusAnd(Op0LHS, Op0RHS, AndRHS, true, I))
+          return BinaryOperator::CreateAnd(V, AndRHS);
+
+        // -x & 1 -> x & 1
+        if (AndRHSMask == 1 && match(Op0LHS, m_Zero()))
+          return BinaryOperator::CreateAnd(Op0RHS, AndRHS);
+
+        // (A - N) & AndRHS -> -N & AndRHS iff A&AndRHS==0 and AndRHS
+        // has 1's for all bits that the subtraction with A might affect.
+        if (Op0I->hasOneUse() && !match(Op0LHS, m_Zero())) {
+          uint32_t BitWidth = AndRHSMask.getBitWidth();
+          uint32_t Zeros = AndRHSMask.countLeadingZeros();
+          APInt Mask = APInt::getLowBitsSet(BitWidth, BitWidth - Zeros);
+
+          if (MaskedValueIsZero(Op0LHS, Mask, 0, &I)) {
+            Value *NewNeg = Builder->CreateNeg(Op0RHS);
+            return BinaryOperator::CreateAnd(NewNeg, AndRHS);
+          }
+        }
+        break;
+
+      case Instruction::Shl:
+      case Instruction::LShr:
+        // (1 << x) & 1 --> zext(x == 0)
+        // (1 >> x) & 1 --> zext(x == 0)
+        if (AndRHSMask == 1 && Op0LHS == AndRHS) {
+          Value *NewICmp =
+            Builder->CreateICmpEQ(Op0RHS, Constant::getNullValue(I.getType()));
+          return new ZExtInst(NewICmp, I.getType());
+        }
+        break;
+      }
+
+      if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1)))
+        if (Instruction *Res = OptAndOp(Op0I, Op0CI, AndRHS, I))
+          return Res;
+    }
+
+    // If this is an integer truncation, and if the source is an 'and' with
+    // immediate, transform it.  This frequently occurs for bitfield accesses.
+    {
+      Value *X = nullptr; ConstantInt *YC = nullptr;
+      if (match(Op0, m_Trunc(m_And(m_Value(X), m_ConstantInt(YC))))) {
+        // Change: and (trunc (and X, YC) to T), C2
+        // into  : and (trunc X to T), trunc(YC) & C2
+        // This will fold the two constants together, which may allow
+        // other simplifications.
+        Value *NewCast = Builder->CreateTrunc(X, I.getType(), "and.shrunk");
+        Constant *C3 = ConstantExpr::getTrunc(YC, I.getType());
+        C3 = ConstantExpr::getAnd(C3, AndRHS);
+        return BinaryOperator::CreateAnd(NewCast, C3);
+      }
+    }
+
+    // Try to fold constant and into select arguments.
+    if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
+      if (Instruction *R = FoldOpIntoSelect(I, SI))
+        return R;
+    if (isa<PHINode>(Op0))
+      if (Instruction *NV = FoldOpIntoPhi(I))
+        return NV;
+  }
+
+  if (Instruction *DeMorgan = matchDeMorgansLaws(I, Builder))
+    return DeMorgan;
+
+  {
+    Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
+    // (A|B) & ~(A&B) -> A^B
+    if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
+        match(Op1, m_Not(m_And(m_Value(C), m_Value(D)))) &&
+        ((A == C && B == D) || (A == D && B == C)))
+      return BinaryOperator::CreateXor(A, B);
+
+    // ~(A&B) & (A|B) -> A^B
+    if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
+        match(Op0, m_Not(m_And(m_Value(C), m_Value(D)))) &&
+        ((A == C && B == D) || (A == D && B == C)))
+      return BinaryOperator::CreateXor(A, B);
+
+    // A&(A^B) => A & ~B
+    {
+      Value *tmpOp0 = Op0;
+      Value *tmpOp1 = Op1;
+      if (Op0->hasOneUse() &&
+          match(Op0, m_Xor(m_Value(A), m_Value(B)))) {
+        if (A == Op1 || B == Op1 ) {
+          tmpOp1 = Op0;
+          tmpOp0 = Op1;
+          // Simplify below
+        }
+      }
+
+      if (tmpOp1->hasOneUse() &&
+          match(tmpOp1, m_Xor(m_Value(A), m_Value(B)))) {
+        if (B == tmpOp0) {
+          std::swap(A, B);
+        }
+        // Notice that the patten (A&(~B)) is actually (A&(-1^B)), so if
+        // A is originally -1 (or a vector of -1 and undefs), then we enter
+        // an endless loop. By checking that A is non-constant we ensure that
+        // we will never get to the loop.
+        if (A == tmpOp0 && !isa<Constant>(A)) // A&(A^B) -> A & ~B
+          return BinaryOperator::CreateAnd(A, Builder->CreateNot(B));
+      }
+    }
+
+    // (A&((~A)|B)) -> A&B
+    if (match(Op0, m_Or(m_Not(m_Specific(Op1)), m_Value(A))) ||
+        match(Op0, m_Or(m_Value(A), m_Not(m_Specific(Op1)))))
+      return BinaryOperator::CreateAnd(A, Op1);
+    if (match(Op1, m_Or(m_Not(m_Specific(Op0)), m_Value(A))) ||
+        match(Op1, m_Or(m_Value(A), m_Not(m_Specific(Op0)))))
+      return BinaryOperator::CreateAnd(A, Op0);
+
+    // (A ^ B) & ((B ^ C) ^ A) -> (A ^ B) & ~C
+    if (match(Op0, m_Xor(m_Value(A), m_Value(B))))
+      if (match(Op1, m_Xor(m_Xor(m_Specific(B), m_Value(C)), m_Specific(A))))
+        if (Op1->hasOneUse() || cast<BinaryOperator>(Op1)->hasOneUse())
+          return BinaryOperator::CreateAnd(Op0, Builder->CreateNot(C));
+
+    // ((A ^ C) ^ B) & (B ^ A) -> (B ^ A) & ~C
+    if (match(Op0, m_Xor(m_Xor(m_Value(A), m_Value(C)), m_Value(B))))
+      if (match(Op1, m_Xor(m_Specific(B), m_Specific(A))))
+        if (Op0->hasOneUse() || cast<BinaryOperator>(Op0)->hasOneUse())
+          return BinaryOperator::CreateAnd(Op1, Builder->CreateNot(C));
+
+    // (A | B) & ((~A) ^ B) -> (A & B)
+    if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
+        match(Op1, m_Xor(m_Not(m_Specific(A)), m_Specific(B))))
+      return BinaryOperator::CreateAnd(A, B);
+
+    // ((~A) ^ B) & (A | B) -> (A & B)
+    if (match(Op0, m_Xor(m_Not(m_Value(A)), m_Value(B))) &&
+        match(Op1, m_Or(m_Specific(A), m_Specific(B))))
+      return BinaryOperator::CreateAnd(A, B);
+  }
+
+  {
+    ICmpInst *LHS = dyn_cast<ICmpInst>(Op0);
+    ICmpInst *RHS = dyn_cast<ICmpInst>(Op1);
+    if (LHS && RHS)
+      if (Value *Res = FoldAndOfICmps(LHS, RHS))
+        return ReplaceInstUsesWith(I, Res);
+
+    // TODO: Make this recursive; it's a little tricky because an arbitrary
+    // number of 'and' instructions might have to be created.
+    Value *X, *Y;
+    if (LHS && match(Op1, m_OneUse(m_And(m_Value(X), m_Value(Y))))) {
+      if (auto *Cmp = dyn_cast<ICmpInst>(X))
+        if (Value *Res = FoldAndOfICmps(LHS, Cmp))
+          return ReplaceInstUsesWith(I, Builder->CreateAnd(Res, Y));
+      if (auto *Cmp = dyn_cast<ICmpInst>(Y))
+        if (Value *Res = FoldAndOfICmps(LHS, Cmp))
+          return ReplaceInstUsesWith(I, Builder->CreateAnd(Res, X));
+    }
+    if (RHS && match(Op0, m_OneUse(m_And(m_Value(X), m_Value(Y))))) {
+      if (auto *Cmp = dyn_cast<ICmpInst>(X))
+        if (Value *Res = FoldAndOfICmps(Cmp, RHS))
+          return ReplaceInstUsesWith(I, Builder->CreateAnd(Res, Y));
+      if (auto *Cmp = dyn_cast<ICmpInst>(Y))
+        if (Value *Res = FoldAndOfICmps(Cmp, RHS))
+          return ReplaceInstUsesWith(I, Builder->CreateAnd(Res, X));
+    }
+  }
+
+  // If and'ing two fcmp, try combine them into one.
+  if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0)))
+    if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1)))
+      if (Value *Res = FoldAndOfFCmps(LHS, RHS))
+        return ReplaceInstUsesWith(I, Res);
+
+
+  if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
+    Value *Op0COp = Op0C->getOperand(0);
+    Type *SrcTy = Op0COp->getType();
+    // fold (and (cast A), (cast B)) -> (cast (and A, B))
+    if (CastInst *Op1C = dyn_cast<CastInst>(Op1)) {
+      if (Op0C->getOpcode() == Op1C->getOpcode() && // same cast kind ?
+          SrcTy == Op1C->getOperand(0)->getType() &&
+          SrcTy->isIntOrIntVectorTy()) {
+        Value *Op1COp = Op1C->getOperand(0);
+
+        // Only do this if the casts both really cause code to be generated.
+        if (ShouldOptimizeCast(Op0C->getOpcode(), Op0COp, I.getType()) &&
+            ShouldOptimizeCast(Op1C->getOpcode(), Op1COp, I.getType())) {
+          Value *NewOp = Builder->CreateAnd(Op0COp, Op1COp, I.getName());
+          return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType());
+        }
+
+        // If this is and(cast(icmp), cast(icmp)), try to fold this even if the
+        // cast is otherwise not optimizable.  This happens for vector sexts.
+        if (ICmpInst *RHS = dyn_cast<ICmpInst>(Op1COp))
+          if (ICmpInst *LHS = dyn_cast<ICmpInst>(Op0COp))
+            if (Value *Res = FoldAndOfICmps(LHS, RHS))
+              return CastInst::Create(Op0C->getOpcode(), Res, I.getType());
+
+        // If this is and(cast(fcmp), cast(fcmp)), try to fold this even if the
+        // cast is otherwise not optimizable.  This happens for vector sexts.
+        if (FCmpInst *RHS = dyn_cast<FCmpInst>(Op1COp))
+          if (FCmpInst *LHS = dyn_cast<FCmpInst>(Op0COp))
+            if (Value *Res = FoldAndOfFCmps(LHS, RHS))
+              return CastInst::Create(Op0C->getOpcode(), Res, I.getType());
+      }
+    }
+
+    // If we are masking off the sign bit of a floating-point value, convert
+    // this to the canonical fabs intrinsic call and cast back to integer.
+    // The backend should know how to optimize fabs().
+    // TODO: This transform should also apply to vectors.
+    ConstantInt *CI;
+    if (isa<BitCastInst>(Op0C) && SrcTy->isFloatingPointTy() &&
+        match(Op1, m_ConstantInt(CI)) && CI->isMaxValue(true)) {
+      Module *M = I.getModule();
+      Function *Fabs = Intrinsic::getDeclaration(M, Intrinsic::fabs, SrcTy);
+      Value *Call = Builder->CreateCall(Fabs, Op0COp, "fabs");
+      return CastInst::CreateBitOrPointerCast(Call, I.getType());
+    }
+  }
+
+  {
+    Value *X = nullptr;
+    bool OpsSwapped = false;
+    // Canonicalize SExt or Not to the LHS
+    if (match(Op1, m_SExt(m_Value())) ||
+        match(Op1, m_Not(m_Value()))) {
+      std::swap(Op0, Op1);
+      OpsSwapped = true;
+    }
+
+    // Fold (and (sext bool to A), B) --> (select bool, B, 0)
+    if (match(Op0, m_SExt(m_Value(X))) &&
+        X->getType()->getScalarType()->isIntegerTy(1)) {
+      Value *Zero = Constant::getNullValue(Op1->getType());
+      return SelectInst::Create(X, Op1, Zero);
+    }
+
+    // Fold (and ~(sext bool to A), B) --> (select bool, 0, B)
+    if (match(Op0, m_Not(m_SExt(m_Value(X)))) &&
+        X->getType()->getScalarType()->isIntegerTy(1)) {
+      Value *Zero = Constant::getNullValue(Op0->getType());
+      return SelectInst::Create(X, Zero, Op1);
+    }
+
+    if (OpsSwapped)
+      std::swap(Op0, Op1);
+  }
+
+  return Changed ? &I : nullptr;
+}
+
+/// Given an OR instruction, check to see if this is a bswap or bitreverse
+/// idiom. If so, insert the new intrinsic and return it.
+Instruction *InstCombiner::MatchBSwapOrBitReverse(BinaryOperator &I) {
+  SmallVector<Instruction*, 4> Insts;
+  if (!recognizeBitReverseOrBSwapIdiom(&I, true, false, Insts))
+    return nullptr;
+  Instruction *LastInst = Insts.pop_back_val();
+  LastInst->removeFromParent();
+
+  for (auto *Inst : Insts)
+    Worklist.Add(Inst);
+  return LastInst;
+}
+
+/// We have an expression of the form (A&C)|(B&D).  Check if A is (cond?-1:0)
+/// and either B or D is ~(cond?-1,0) or (cond?0,-1), then we can simplify this
+/// expression to "cond ? C : D or B".
+static Instruction *MatchSelectFromAndOr(Value *A, Value *B,
+                                         Value *C, Value *D) {
+  // If A is not a select of -1/0, this cannot match.
+  Value *Cond = nullptr;
+  if (!match(A, m_SExt(m_Value(Cond))) ||
+      !Cond->getType()->isIntegerTy(1))
+    return nullptr;
+
+  // ((cond?-1:0)&C) | (B&(cond?0:-1)) -> cond ? C : B.
+  if (match(D, m_Not(m_SExt(m_Specific(Cond)))))
+    return SelectInst::Create(Cond, C, B);
+  if (match(D, m_SExt(m_Not(m_Specific(Cond)))))
+    return SelectInst::Create(Cond, C, B);
+
+  // ((cond?-1:0)&C) | ((cond?0:-1)&D) -> cond ? C : D.
+  if (match(B, m_Not(m_SExt(m_Specific(Cond)))))
+    return SelectInst::Create(Cond, C, D);
+  if (match(B, m_SExt(m_Not(m_Specific(Cond)))))
+    return SelectInst::Create(Cond, C, D);
+  return nullptr;
+}
+
+/// Fold (icmp)|(icmp) if possible.
+Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS,
+                                   Instruction *CxtI) {
+  ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate();
+
+  // Fold (iszero(A & K1) | iszero(A & K2)) ->  (A & (K1 | K2)) != (K1 | K2)
+  // if K1 and K2 are a one-bit mask.
+  ConstantInt *LHSCst = dyn_cast<ConstantInt>(LHS->getOperand(1));
+  ConstantInt *RHSCst = dyn_cast<ConstantInt>(RHS->getOperand(1));
+
+  if (LHS->getPredicate() == ICmpInst::ICMP_EQ && LHSCst && LHSCst->isZero() &&
+      RHS->getPredicate() == ICmpInst::ICMP_EQ && RHSCst && RHSCst->isZero()) {
+
+    BinaryOperator *LAnd = dyn_cast<BinaryOperator>(LHS->getOperand(0));
+    BinaryOperator *RAnd = dyn_cast<BinaryOperator>(RHS->getOperand(0));
+    if (LAnd && RAnd && LAnd->hasOneUse() && RHS->hasOneUse() &&
+        LAnd->getOpcode() == Instruction::And &&
+        RAnd->getOpcode() == Instruction::And) {
+
+      Value *Mask = nullptr;
+      Value *Masked = nullptr;
+      if (LAnd->getOperand(0) == RAnd->getOperand(0) &&
+          isKnownToBeAPowerOfTwo(LAnd->getOperand(1), DL, false, 0, AC, CxtI,
+                                 DT) &&
+          isKnownToBeAPowerOfTwo(RAnd->getOperand(1), DL, false, 0, AC, CxtI,
+                                 DT)) {
+        Mask = Builder->CreateOr(LAnd->getOperand(1), RAnd->getOperand(1));
+        Masked = Builder->CreateAnd(LAnd->getOperand(0), Mask);
+      } else if (LAnd->getOperand(1) == RAnd->getOperand(1) &&
+                 isKnownToBeAPowerOfTwo(LAnd->getOperand(0), DL, false, 0, AC,
+                                        CxtI, DT) &&
+                 isKnownToBeAPowerOfTwo(RAnd->getOperand(0), DL, false, 0, AC,
+                                        CxtI, DT)) {
+        Mask = Builder->CreateOr(LAnd->getOperand(0), RAnd->getOperand(0));
+        Masked = Builder->CreateAnd(LAnd->getOperand(1), Mask);
+      }
+
+      if (Masked)
+        return Builder->CreateICmp(ICmpInst::ICMP_NE, Masked, Mask);
+    }
+  }
+
+  // Fold (icmp ult/ule (A + C1), C3) | (icmp ult/ule (A + C2), C3)
+  //                   -->  (icmp ult/ule ((A & ~(C1 ^ C2)) + max(C1, C2)), C3)
+  // The original condition actually refers to the following two ranges:
+  // [MAX_UINT-C1+1, MAX_UINT-C1+1+C3] and [MAX_UINT-C2+1, MAX_UINT-C2+1+C3]
+  // We can fold these two ranges if:
+  // 1) C1 and C2 is unsigned greater than C3.
+  // 2) The two ranges are separated.
+  // 3) C1 ^ C2 is one-bit mask.
+  // 4) LowRange1 ^ LowRange2 and HighRange1 ^ HighRange2 are one-bit mask.
+  // This implies all values in the two ranges differ by exactly one bit.
+
+  if ((LHSCC == ICmpInst::ICMP_ULT || LHSCC == ICmpInst::ICMP_ULE) &&
+      LHSCC == RHSCC && LHSCst && RHSCst && LHS->hasOneUse() &&
+      RHS->hasOneUse() && LHSCst->getType() == RHSCst->getType() &&
+      LHSCst->getValue() == (RHSCst->getValue())) {
+
+    Value *LAdd = LHS->getOperand(0);
+    Value *RAdd = RHS->getOperand(0);
+
+    Value *LAddOpnd, *RAddOpnd;
+    ConstantInt *LAddCst, *RAddCst;
+    if (match(LAdd, m_Add(m_Value(LAddOpnd), m_ConstantInt(LAddCst))) &&
+        match(RAdd, m_Add(m_Value(RAddOpnd), m_ConstantInt(RAddCst))) &&
+        LAddCst->getValue().ugt(LHSCst->getValue()) &&
+        RAddCst->getValue().ugt(LHSCst->getValue())) {
+
+      APInt DiffCst = LAddCst->getValue() ^ RAddCst->getValue();
+      if (LAddOpnd == RAddOpnd && DiffCst.isPowerOf2()) {
+        ConstantInt *MaxAddCst = nullptr;
+        if (LAddCst->getValue().ult(RAddCst->getValue()))
+          MaxAddCst = RAddCst;
+        else
+          MaxAddCst = LAddCst;
+
+        APInt RRangeLow = -RAddCst->getValue();
+        APInt RRangeHigh = RRangeLow + LHSCst->getValue();
+        APInt LRangeLow = -LAddCst->getValue();
+        APInt LRangeHigh = LRangeLow + LHSCst->getValue();
+        APInt LowRangeDiff = RRangeLow ^ LRangeLow;
+        APInt HighRangeDiff = RRangeHigh ^ LRangeHigh;
+        APInt RangeDiff = LRangeLow.sgt(RRangeLow) ? LRangeLow - RRangeLow
+                                                   : RRangeLow - LRangeLow;
+
+        if (LowRangeDiff.isPowerOf2() && LowRangeDiff == HighRangeDiff &&
+            RangeDiff.ugt(LHSCst->getValue())) {
+          Value *MaskCst = ConstantInt::get(LAddCst->getType(), ~DiffCst);
+
+          Value *NewAnd = Builder->CreateAnd(LAddOpnd, MaskCst);
+          Value *NewAdd = Builder->CreateAdd(NewAnd, MaxAddCst);
+          return (Builder->CreateICmp(LHS->getPredicate(), NewAdd, LHSCst));
+        }
+      }
+    }
+  }
+
+  // (icmp1 A, B) | (icmp2 A, B) --> (icmp3 A, B)
+  if (PredicatesFoldable(LHSCC, RHSCC)) {
+    if (LHS->getOperand(0) == RHS->getOperand(1) &&
+        LHS->getOperand(1) == RHS->getOperand(0))
+      LHS->swapOperands();
+    if (LHS->getOperand(0) == RHS->getOperand(0) &&
+        LHS->getOperand(1) == RHS->getOperand(1)) {
+      Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
+      unsigned Code = getICmpCode(LHS) | getICmpCode(RHS);
+      bool isSigned = LHS->isSigned() || RHS->isSigned();
+      return getNewICmpValue(isSigned, Code, Op0, Op1, Builder);
+    }
+  }
+
+  // handle (roughly):
+  // (icmp ne (A & B), C) | (icmp ne (A & D), E)
+  if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, false, Builder))
+    return V;
+
+  Value *Val = LHS->getOperand(0), *Val2 = RHS->getOperand(0);
+  if (LHS->hasOneUse() || RHS->hasOneUse()) {
+    // (icmp eq B, 0) | (icmp ult A, B) -> (icmp ule A, B-1)
+    // (icmp eq B, 0) | (icmp ugt B, A) -> (icmp ule A, B-1)
+    Value *A = nullptr, *B = nullptr;
+    if (LHSCC == ICmpInst::ICMP_EQ && LHSCst && LHSCst->isZero()) {
+      B = Val;
+      if (RHSCC == ICmpInst::ICMP_ULT && Val == RHS->getOperand(1))
+        A = Val2;
+      else if (RHSCC == ICmpInst::ICMP_UGT && Val == Val2)
+        A = RHS->getOperand(1);
+    }
+    // (icmp ult A, B) | (icmp eq B, 0) -> (icmp ule A, B-1)
+    // (icmp ugt B, A) | (icmp eq B, 0) -> (icmp ule A, B-1)
+    else if (RHSCC == ICmpInst::ICMP_EQ && RHSCst && RHSCst->isZero()) {
+      B = Val2;
+      if (LHSCC == ICmpInst::ICMP_ULT && Val2 == LHS->getOperand(1))
+        A = Val;
+      else if (LHSCC == ICmpInst::ICMP_UGT && Val2 == Val)
+        A = LHS->getOperand(1);
+    }
+    if (A && B)
+      return Builder->CreateICmp(
+          ICmpInst::ICMP_UGE,
+          Builder->CreateAdd(B, ConstantInt::getSigned(B->getType(), -1)), A);
+  }
+
+  // E.g. (icmp slt x, 0) | (icmp sgt x, n) --> icmp ugt x, n
+  if (Value *V = simplifyRangeCheck(LHS, RHS, /*Inverted=*/true))
+    return V;
+
+  // E.g. (icmp sgt x, n) | (icmp slt x, 0) --> icmp ugt x, n
+  if (Value *V = simplifyRangeCheck(RHS, LHS, /*Inverted=*/true))
+    return V;
+ 
+  // This only handles icmp of constants: (icmp1 A, C1) | (icmp2 B, C2).
+  if (!LHSCst || !RHSCst) return nullptr;
+
+  if (LHSCst == RHSCst && LHSCC == RHSCC) {
+    // (icmp ne A, 0) | (icmp ne B, 0) --> (icmp ne (A|B), 0)
+    if (LHSCC == ICmpInst::ICMP_NE && LHSCst->isZero()) {
+      Value *NewOr = Builder->CreateOr(Val, Val2);
+      return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
+    }
+  }
+
+  // (icmp ult (X + CA), C1) | (icmp eq X, C2) -> (icmp ule (X + CA), C1)
+  //   iff C2 + CA == C1.
+  if (LHSCC == ICmpInst::ICMP_ULT && RHSCC == ICmpInst::ICMP_EQ) {
+    ConstantInt *AddCst;
+    if (match(Val, m_Add(m_Specific(Val2), m_ConstantInt(AddCst))))
+      if (RHSCst->getValue() + AddCst->getValue() == LHSCst->getValue())
+        return Builder->CreateICmpULE(Val, LHSCst);
+  }
+
+  // From here on, we only handle:
+  //    (icmp1 A, C1) | (icmp2 A, C2) --> something simpler.
+  if (Val != Val2) return nullptr;
+
+  // ICMP_[US][GL]E X, CST is folded to ICMP_[US][GL]T elsewhere.
+  if (LHSCC == ICmpInst::ICMP_UGE || LHSCC == ICmpInst::ICMP_ULE ||
+      RHSCC == ICmpInst::ICMP_UGE || RHSCC == ICmpInst::ICMP_ULE ||
+      LHSCC == ICmpInst::ICMP_SGE || LHSCC == ICmpInst::ICMP_SLE ||
+      RHSCC == ICmpInst::ICMP_SGE || RHSCC == ICmpInst::ICMP_SLE)
+    return nullptr;
+
+  // We can't fold (ugt x, C) | (sgt x, C2).
+  if (!PredicatesFoldable(LHSCC, RHSCC))
+    return nullptr;
+
+  // Ensure that the larger constant is on the RHS.
+  bool ShouldSwap;
+  if (CmpInst::isSigned(LHSCC) ||
+      (ICmpInst::isEquality(LHSCC) &&
+       CmpInst::isSigned(RHSCC)))
+    ShouldSwap = LHSCst->getValue().sgt(RHSCst->getValue());
+  else
+    ShouldSwap = LHSCst->getValue().ugt(RHSCst->getValue());
+
+  if (ShouldSwap) {
+    std::swap(LHS, RHS);
+    std::swap(LHSCst, RHSCst);
+    std::swap(LHSCC, RHSCC);
+  }
+
+  // At this point, we know we have two icmp instructions
+  // comparing a value against two constants and or'ing the result
+  // together.  Because of the above check, we know that we only have
+  // ICMP_EQ, ICMP_NE, ICMP_LT, and ICMP_GT here. We also know (from the
+  // icmp folding check above), that the two constants are not
+  // equal.
+  assert(LHSCst != RHSCst && "Compares not folded above?");
+
+  switch (LHSCC) {
+  default: llvm_unreachable("Unknown integer condition code!");
+  case ICmpInst::ICMP_EQ:
+    switch (RHSCC) {
+    default: llvm_unreachable("Unknown integer condition code!");
+    case ICmpInst::ICMP_EQ:
+      if (LHS->getOperand(0) == RHS->getOperand(0)) {
+        // if LHSCst and RHSCst differ only by one bit:
+        // (A == C1 || A == C2) -> (A | (C1 ^ C2)) == C2
+        assert(LHSCst->getValue().ule(LHSCst->getValue()));
+
+        APInt Xor = LHSCst->getValue() ^ RHSCst->getValue();
+        if (Xor.isPowerOf2()) {
+          Value *Cst = Builder->getInt(Xor);
+          Value *Or = Builder->CreateOr(LHS->getOperand(0), Cst);
+          return Builder->CreateICmp(ICmpInst::ICMP_EQ, Or, RHSCst);
+        }
+      }
+
+      if (LHSCst == SubOne(RHSCst)) {
+        // (X == 13 | X == 14) -> X-13 <u 2
+        Constant *AddCST = ConstantExpr::getNeg(LHSCst);
+        Value *Add = Builder->CreateAdd(Val, AddCST, Val->getName()+".off");
+        AddCST = ConstantExpr::getSub(AddOne(RHSCst), LHSCst);
+        return Builder->CreateICmpULT(Add, AddCST);
+      }
+
+      break;                         // (X == 13 | X == 15) -> no change
+    case ICmpInst::ICMP_UGT:         // (X == 13 | X u> 14) -> no change
+    case ICmpInst::ICMP_SGT:         // (X == 13 | X s> 14) -> no change
+      break;
+    case ICmpInst::ICMP_NE:          // (X == 13 | X != 15) -> X != 15
+    case ICmpInst::ICMP_ULT:         // (X == 13 | X u< 15) -> X u< 15
+    case ICmpInst::ICMP_SLT:         // (X == 13 | X s< 15) -> X s< 15
+      return RHS;
+    }
+    break;
+  case ICmpInst::ICMP_NE:
+    switch (RHSCC) {
+    default: llvm_unreachable("Unknown integer condition code!");
+    case ICmpInst::ICMP_EQ:          // (X != 13 | X == 15) -> X != 13
+    case ICmpInst::ICMP_UGT:         // (X != 13 | X u> 15) -> X != 13
+    case ICmpInst::ICMP_SGT:         // (X != 13 | X s> 15) -> X != 13
+      return LHS;
+    case ICmpInst::ICMP_NE:          // (X != 13 | X != 15) -> true
+    case ICmpInst::ICMP_ULT:         // (X != 13 | X u< 15) -> true
+    case ICmpInst::ICMP_SLT:         // (X != 13 | X s< 15) -> true
+      return Builder->getTrue();
+    }
+  case ICmpInst::ICMP_ULT:
+    switch (RHSCC) {
+    default: llvm_unreachable("Unknown integer condition code!");
+    case ICmpInst::ICMP_EQ:         // (X u< 13 | X == 14) -> no change
+      break;
+    case ICmpInst::ICMP_UGT:        // (X u< 13 | X u> 15) -> (X-13) u> 2
+      // If RHSCst is [us]MAXINT, it is always false.  Not handling
+      // this can cause overflow.
+      if (RHSCst->isMaxValue(false))
+        return LHS;
+      return InsertRangeTest(Val, LHSCst, AddOne(RHSCst), false, false);
+    case ICmpInst::ICMP_SGT:        // (X u< 13 | X s> 15) -> no change
+      break;
+    case ICmpInst::ICMP_NE:         // (X u< 13 | X != 15) -> X != 15
+    case ICmpInst::ICMP_ULT:        // (X u< 13 | X u< 15) -> X u< 15
+      return RHS;
+    case ICmpInst::ICMP_SLT:        // (X u< 13 | X s< 15) -> no change
+      break;
+    }
+    break;
+  case ICmpInst::ICMP_SLT:
+    switch (RHSCC) {
+    default: llvm_unreachable("Unknown integer condition code!");
+    case ICmpInst::ICMP_EQ:         // (X s< 13 | X == 14) -> no change
+      break;
+    case ICmpInst::ICMP_SGT:        // (X s< 13 | X s> 15) -> (X-13) s> 2
+      // If RHSCst is [us]MAXINT, it is always false.  Not handling
+      // this can cause overflow.
+      if (RHSCst->isMaxValue(true))
+        return LHS;
+      return InsertRangeTest(Val, LHSCst, AddOne(RHSCst), true, false);
+    case ICmpInst::ICMP_UGT:        // (X s< 13 | X u> 15) -> no change
+      break;
+    case ICmpInst::ICMP_NE:         // (X s< 13 | X != 15) -> X != 15
+    case ICmpInst::ICMP_SLT:        // (X s< 13 | X s< 15) -> X s< 15
+      return RHS;
+    case ICmpInst::ICMP_ULT:        // (X s< 13 | X u< 15) -> no change
+      break;
+    }
+    break;
+  case ICmpInst::ICMP_UGT:
+    switch (RHSCC) {
+    default: llvm_unreachable("Unknown integer condition code!");
+    case ICmpInst::ICMP_EQ:         // (X u> 13 | X == 15) -> X u> 13
+    case ICmpInst::ICMP_UGT:        // (X u> 13 | X u> 15) -> X u> 13
+      return LHS;
+    case ICmpInst::ICMP_SGT:        // (X u> 13 | X s> 15) -> no change
+      break;
+    case ICmpInst::ICMP_NE:         // (X u> 13 | X != 15) -> true
+    case ICmpInst::ICMP_ULT:        // (X u> 13 | X u< 15) -> true
+      return Builder->getTrue();
+    case ICmpInst::ICMP_SLT:        // (X u> 13 | X s< 15) -> no change
+      break;
+    }
+    break;
+  case ICmpInst::ICMP_SGT:
+    switch (RHSCC) {
+    default: llvm_unreachable("Unknown integer condition code!");
+    case ICmpInst::ICMP_EQ:         // (X s> 13 | X == 15) -> X > 13
+    case ICmpInst::ICMP_SGT:        // (X s> 13 | X s> 15) -> X > 13
+      return LHS;
+    case ICmpInst::ICMP_UGT:        // (X s> 13 | X u> 15) -> no change
+      break;
+    case ICmpInst::ICMP_NE:         // (X s> 13 | X != 15) -> true
+    case ICmpInst::ICMP_SLT:        // (X s> 13 | X s< 15) -> true
+      return Builder->getTrue();
+    case ICmpInst::ICMP_ULT:        // (X s> 13 | X u< 15) -> no change
+      break;
+    }
+    break;
+  }
+  return nullptr;
+}
+
+/// Optimize (fcmp)|(fcmp).  NOTE: Unlike the rest of instcombine, this returns
+/// a Value which should already be inserted into the function.
+Value *InstCombiner::FoldOrOfFCmps(FCmpInst *LHS, FCmpInst *RHS) {
+  if (LHS->getPredicate() == FCmpInst::FCMP_UNO &&
+      RHS->getPredicate() == FCmpInst::FCMP_UNO &&
+      LHS->getOperand(0)->getType() == RHS->getOperand(0)->getType()) {
+    if (ConstantFP *LHSC = dyn_cast<ConstantFP>(LHS->getOperand(1)))
+      if (ConstantFP *RHSC = dyn_cast<ConstantFP>(RHS->getOperand(1))) {
+        // If either of the constants are nans, then the whole thing returns
+        // true.
+        if (LHSC->getValueAPF().isNaN() || RHSC->getValueAPF().isNaN())
+          return Builder->getTrue();
+
+        // Otherwise, no need to compare the two constants, compare the
+        // rest.
+        return Builder->CreateFCmpUNO(LHS->getOperand(0), RHS->getOperand(0));
+      }
+
+    // Handle vector zeros.  This occurs because the canonical form of
+    // "fcmp uno x,x" is "fcmp uno x, 0".
+    if (isa<ConstantAggregateZero>(LHS->getOperand(1)) &&
+        isa<ConstantAggregateZero>(RHS->getOperand(1)))
+      return Builder->CreateFCmpUNO(LHS->getOperand(0), RHS->getOperand(0));
+
+    return nullptr;
+  }
+
+  Value *Op0LHS = LHS->getOperand(0), *Op0RHS = LHS->getOperand(1);
+  Value *Op1LHS = RHS->getOperand(0), *Op1RHS = RHS->getOperand(1);
+  FCmpInst::Predicate Op0CC = LHS->getPredicate(), Op1CC = RHS->getPredicate();
+
+  if (Op0LHS == Op1RHS && Op0RHS == Op1LHS) {
+    // Swap RHS operands to match LHS.
+    Op1CC = FCmpInst::getSwappedPredicate(Op1CC);
+    std::swap(Op1LHS, Op1RHS);
+  }
+  if (Op0LHS == Op1LHS && Op0RHS == Op1RHS) {
+    // Simplify (fcmp cc0 x, y) | (fcmp cc1 x, y).
+    if (Op0CC == Op1CC)
+      return Builder->CreateFCmp((FCmpInst::Predicate)Op0CC, Op0LHS, Op0RHS);
+    if (Op0CC == FCmpInst::FCMP_TRUE || Op1CC == FCmpInst::FCMP_TRUE)
+      return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 1);
+    if (Op0CC == FCmpInst::FCMP_FALSE)
+      return RHS;
+    if (Op1CC == FCmpInst::FCMP_FALSE)
+      return LHS;
+    bool Op0Ordered;
+    bool Op1Ordered;
+    unsigned Op0Pred = getFCmpCode(Op0CC, Op0Ordered);
+    unsigned Op1Pred = getFCmpCode(Op1CC, Op1Ordered);
+    if (Op0Ordered == Op1Ordered) {
+      // If both are ordered or unordered, return a new fcmp with
+      // or'ed predicates.
+      return getFCmpValue(Op0Ordered, Op0Pred|Op1Pred, Op0LHS, Op0RHS, Builder);
+    }
+  }
+  return nullptr;
+}
+
+/// This helper function folds:
+///
+///     ((A | B) & C1) | (B & C2)
+///
+/// into:
+///
+///     (A & C1) | B
+///
+/// when the XOR of the two constants is "all ones" (-1).
+Instruction *InstCombiner::FoldOrWithConstants(BinaryOperator &I, Value *Op,
+                                               Value *A, Value *B, Value *C) {
+  ConstantInt *CI1 = dyn_cast<ConstantInt>(C);
+  if (!CI1) return nullptr;
+
+  Value *V1 = nullptr;
+  ConstantInt *CI2 = nullptr;
+  if (!match(Op, m_And(m_Value(V1), m_ConstantInt(CI2)))) return nullptr;
+
+  APInt Xor = CI1->getValue() ^ CI2->getValue();
+  if (!Xor.isAllOnesValue()) return nullptr;
+
+  if (V1 == A || V1 == B) {
+    Value *NewOp = Builder->CreateAnd((V1 == A) ? B : A, CI1);
+    return BinaryOperator::CreateOr(NewOp, V1);
+  }
+
+  return nullptr;
+}
+
+/// \brief This helper function folds:
+///
+///     ((A | B) & C1) ^ (B & C2)
+///
+/// into:
+///
+///     (A & C1) ^ B
+///
+/// when the XOR of the two constants is "all ones" (-1).
+Instruction *InstCombiner::FoldXorWithConstants(BinaryOperator &I, Value *Op,
+                                                Value *A, Value *B, Value *C) {
+  ConstantInt *CI1 = dyn_cast<ConstantInt>(C);
+  if (!CI1)
+    return nullptr;
+
+  Value *V1 = nullptr;
+  ConstantInt *CI2 = nullptr;
+  if (!match(Op, m_And(m_Value(V1), m_ConstantInt(CI2))))
+    return nullptr;
+
+  APInt Xor = CI1->getValue() ^ CI2->getValue();
+  if (!Xor.isAllOnesValue())
+    return nullptr;
+
+  if (V1 == A || V1 == B) {
+    Value *NewOp = Builder->CreateAnd(V1 == A ? B : A, CI1);
+    return BinaryOperator::CreateXor(NewOp, V1);
+  }
+
+  return nullptr;
+}
+
+Instruction *InstCombiner::visitOr(BinaryOperator &I) {
+  bool Changed = SimplifyAssociativeOrCommutative(I);
+  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+
+  if (Value *V = SimplifyVectorOp(I))
+    return ReplaceInstUsesWith(I, V);
+
+  if (Value *V = SimplifyOrInst(Op0, Op1, DL, TLI, DT, AC))
+    return ReplaceInstUsesWith(I, V);
+
+  // (A&B)|(A&C) -> A&(B|C) etc
+  if (Value *V = SimplifyUsingDistributiveLaws(I))
+    return ReplaceInstUsesWith(I, V);
+
+  // See if we can simplify any instructions used by the instruction whose sole
+  // purpose is to compute bits we don't care about.
+  if (SimplifyDemandedInstructionBits(I))
+    return &I;
+
+  if (Value *V = SimplifyBSwap(I))
+    return ReplaceInstUsesWith(I, V);
+
+  if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
+    ConstantInt *C1 = nullptr; Value *X = nullptr;
+    // (X & C1) | C2 --> (X | C2) & (C1|C2)
+    // iff (C1 & C2) == 0.
+    if (match(Op0, m_And(m_Value(X), m_ConstantInt(C1))) &&
+        (RHS->getValue() & C1->getValue()) != 0 &&
+        Op0->hasOneUse()) {
+      Value *Or = Builder->CreateOr(X, RHS);
+      Or->takeName(Op0);
+      return BinaryOperator::CreateAnd(Or,
+                             Builder->getInt(RHS->getValue() | C1->getValue()));
+    }
+
+    // (X ^ C1) | C2 --> (X | C2) ^ (C1&~C2)
+    if (match(Op0, m_Xor(m_Value(X), m_ConstantInt(C1))) &&
+        Op0->hasOneUse()) {
+      Value *Or = Builder->CreateOr(X, RHS);
+      Or->takeName(Op0);
+      return BinaryOperator::CreateXor(Or,
+                            Builder->getInt(C1->getValue() & ~RHS->getValue()));
+    }
+
+    // Try to fold constant and into select arguments.
+    if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
+      if (Instruction *R = FoldOpIntoSelect(I, SI))
+        return R;
+
+    if (isa<PHINode>(Op0))
+      if (Instruction *NV = FoldOpIntoPhi(I))
+        return NV;
+  }
+
+  Value *A = nullptr, *B = nullptr;
+  ConstantInt *C1 = nullptr, *C2 = nullptr;
+
+  // (A | B) | C  and  A | (B | C)                  -> bswap if possible.
+  bool OrOfOrs = match(Op0, m_Or(m_Value(), m_Value())) ||
+                 match(Op1, m_Or(m_Value(), m_Value()));
+  // (A >> B) | (C << D)  and  (A << B) | (B >> C)  -> bswap if possible.
+  bool OrOfShifts = match(Op0, m_LogicalShift(m_Value(), m_Value())) &&
+                    match(Op1, m_LogicalShift(m_Value(), m_Value()));
+  // (A & B) | (C & D)                              -> bswap if possible.
+  bool OrOfAnds = match(Op0, m_And(m_Value(), m_Value())) &&
+                  match(Op1, m_And(m_Value(), m_Value()));
+
+  if (OrOfOrs || OrOfShifts || OrOfAnds)
+    if (Instruction *BSwap = MatchBSwapOrBitReverse(I))
+      return BSwap;
+
+  // (X^C)|Y -> (X|Y)^C iff Y&C == 0
+  if (Op0->hasOneUse() &&
+      match(Op0, m_Xor(m_Value(A), m_ConstantInt(C1))) &&
+      MaskedValueIsZero(Op1, C1->getValue(), 0, &I)) {
+    Value *NOr = Builder->CreateOr(A, Op1);
+    NOr->takeName(Op0);
+    return BinaryOperator::CreateXor(NOr, C1);
+  }
+
+  // Y|(X^C) -> (X|Y)^C iff Y&C == 0
+  if (Op1->hasOneUse() &&
+      match(Op1, m_Xor(m_Value(A), m_ConstantInt(C1))) &&
+      MaskedValueIsZero(Op0, C1->getValue(), 0, &I)) {
+    Value *NOr = Builder->CreateOr(A, Op0);
+    NOr->takeName(Op0);
+    return BinaryOperator::CreateXor(NOr, C1);
+  }
+
+  // ((~A & B) | A) -> (A | B)
+  if (match(Op0, m_And(m_Not(m_Value(A)), m_Value(B))) &&
+      match(Op1, m_Specific(A)))
+    return BinaryOperator::CreateOr(A, B);
+
+  // ((A & B) | ~A) -> (~A | B)
+  if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
+      match(Op1, m_Not(m_Specific(A))))
+    return BinaryOperator::CreateOr(Builder->CreateNot(A), B);
+
+  // (A & (~B)) | (A ^ B) -> (A ^ B)
+  if (match(Op0, m_And(m_Value(A), m_Not(m_Value(B)))) &&
+      match(Op1, m_Xor(m_Specific(A), m_Specific(B))))
+    return BinaryOperator::CreateXor(A, B);
+
+  // (A ^ B) | ( A & (~B)) -> (A ^ B)
+  if (match(Op0, m_Xor(m_Value(A), m_Value(B))) &&
+      match(Op1, m_And(m_Specific(A), m_Not(m_Specific(B)))))
+    return BinaryOperator::CreateXor(A, B);
+
+  // (A & C)|(B & D)
+  Value *C = nullptr, *D = nullptr;
+  if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
+      match(Op1, m_And(m_Value(B), m_Value(D)))) {
+    Value *V1 = nullptr, *V2 = nullptr;
+    C1 = dyn_cast<ConstantInt>(C);
+    C2 = dyn_cast<ConstantInt>(D);
+    if (C1 && C2) {  // (A & C1)|(B & C2)
+      if ((C1->getValue() & C2->getValue()) == 0) {
+        // ((V | N) & C1) | (V & C2) --> (V|N) & (C1|C2)
+        // iff (C1&C2) == 0 and (N&~C1) == 0
+        if (match(A, m_Or(m_Value(V1), m_Value(V2))) &&
+            ((V1 == B &&
+              MaskedValueIsZero(V2, ~C1->getValue(), 0, &I)) || // (V|N)
+             (V2 == B &&
+              MaskedValueIsZero(V1, ~C1->getValue(), 0, &I))))  // (N|V)
+          return BinaryOperator::CreateAnd(A,
+                                Builder->getInt(C1->getValue()|C2->getValue()));
+        // Or commutes, try both ways.
+        if (match(B, m_Or(m_Value(V1), m_Value(V2))) &&
+            ((V1 == A &&
+              MaskedValueIsZero(V2, ~C2->getValue(), 0, &I)) || // (V|N)
+             (V2 == A &&
+              MaskedValueIsZero(V1, ~C2->getValue(), 0, &I))))  // (N|V)
+          return BinaryOperator::CreateAnd(B,
+                                Builder->getInt(C1->getValue()|C2->getValue()));
+
+        // ((V|C3)&C1) | ((V|C4)&C2) --> (V|C3|C4)&(C1|C2)
+        // iff (C1&C2) == 0 and (C3&~C1) == 0 and (C4&~C2) == 0.
+        ConstantInt *C3 = nullptr, *C4 = nullptr;
+        if (match(A, m_Or(m_Value(V1), m_ConstantInt(C3))) &&
+            (C3->getValue() & ~C1->getValue()) == 0 &&
+            match(B, m_Or(m_Specific(V1), m_ConstantInt(C4))) &&
+            (C4->getValue() & ~C2->getValue()) == 0) {
+          V2 = Builder->CreateOr(V1, ConstantExpr::getOr(C3, C4), "bitfield");
+          return BinaryOperator::CreateAnd(V2,
+                                Builder->getInt(C1->getValue()|C2->getValue()));
+        }
+      }
+    }
+
+    // (A & (C0?-1:0)) | (B & ~(C0?-1:0)) ->  C0 ? A : B, and commuted variants.
+    // Don't do this for vector select idioms, the code generator doesn't handle
+    // them well yet.
+    if (!I.getType()->isVectorTy()) {
+      if (Instruction *Match = MatchSelectFromAndOr(A, B, C, D))
+        return Match;
+      if (Instruction *Match = MatchSelectFromAndOr(B, A, D, C))
+        return Match;
+      if (Instruction *Match = MatchSelectFromAndOr(C, B, A, D))
+        return Match;
+      if (Instruction *Match = MatchSelectFromAndOr(D, A, B, C))
+        return Match;
+    }
+
+    // ((A&~B)|(~A&B)) -> A^B
+    if ((match(C, m_Not(m_Specific(D))) &&
+         match(B, m_Not(m_Specific(A)))))
+      return BinaryOperator::CreateXor(A, D);
+    // ((~B&A)|(~A&B)) -> A^B
+    if ((match(A, m_Not(m_Specific(D))) &&
+         match(B, m_Not(m_Specific(C)))))
+      return BinaryOperator::CreateXor(C, D);
+    // ((A&~B)|(B&~A)) -> A^B
+    if ((match(C, m_Not(m_Specific(B))) &&
+         match(D, m_Not(m_Specific(A)))))
+      return BinaryOperator::CreateXor(A, B);
+    // ((~B&A)|(B&~A)) -> A^B
+    if ((match(A, m_Not(m_Specific(B))) &&
+         match(D, m_Not(m_Specific(C)))))
+      return BinaryOperator::CreateXor(C, B);
+
+    // ((A|B)&1)|(B&-2) -> (A&1) | B
+    if (match(A, m_Or(m_Value(V1), m_Specific(B))) ||
+        match(A, m_Or(m_Specific(B), m_Value(V1)))) {
+      Instruction *Ret = FoldOrWithConstants(I, Op1, V1, B, C);
+      if (Ret) return Ret;
+    }
+    // (B&-2)|((A|B)&1) -> (A&1) | B
+    if (match(B, m_Or(m_Specific(A), m_Value(V1))) ||
+        match(B, m_Or(m_Value(V1), m_Specific(A)))) {
+      Instruction *Ret = FoldOrWithConstants(I, Op0, A, V1, D);
+      if (Ret) return Ret;
+    }
+    // ((A^B)&1)|(B&-2) -> (A&1) ^ B
+    if (match(A, m_Xor(m_Value(V1), m_Specific(B))) ||
+        match(A, m_Xor(m_Specific(B), m_Value(V1)))) {
+      Instruction *Ret = FoldXorWithConstants(I, Op1, V1, B, C);
+      if (Ret) return Ret;
+    }
+    // (B&-2)|((A^B)&1) -> (A&1) ^ B
+    if (match(B, m_Xor(m_Specific(A), m_Value(V1))) ||
+        match(B, m_Xor(m_Value(V1), m_Specific(A)))) {
+      Instruction *Ret = FoldXorWithConstants(I, Op0, A, V1, D);
+      if (Ret) return Ret;
+    }
+  }
+
+  // (A ^ B) | ((B ^ C) ^ A) -> (A ^ B) | C
+  if (match(Op0, m_Xor(m_Value(A), m_Value(B))))
+    if (match(Op1, m_Xor(m_Xor(m_Specific(B), m_Value(C)), m_Specific(A))))
+      if (Op1->hasOneUse() || cast<BinaryOperator>(Op1)->hasOneUse())
+        return BinaryOperator::CreateOr(Op0, C);
+
+  // ((A ^ C) ^ B) | (B ^ A) -> (B ^ A) | C
+  if (match(Op0, m_Xor(m_Xor(m_Value(A), m_Value(C)), m_Value(B))))
+    if (match(Op1, m_Xor(m_Specific(B), m_Specific(A))))
+      if (Op0->hasOneUse() || cast<BinaryOperator>(Op0)->hasOneUse())
+        return BinaryOperator::CreateOr(Op1, C);
+
+  // ((B | C) & A) | B -> B | (A & C)
+  if (match(Op0, m_And(m_Or(m_Specific(Op1), m_Value(C)), m_Value(A))))
+    return BinaryOperator::CreateOr(Op1, Builder->CreateAnd(A, C));
+
+  if (Instruction *DeMorgan = matchDeMorgansLaws(I, Builder))
+    return DeMorgan;
+
+  // Canonicalize xor to the RHS.
+  bool SwappedForXor = false;
+  if (match(Op0, m_Xor(m_Value(), m_Value()))) {
+    std::swap(Op0, Op1);
+    SwappedForXor = true;
+  }
+
+  // A | ( A ^ B) -> A |  B
+  // A | (~A ^ B) -> A | ~B
+  // (A & B) | (A ^ B)
+  if (match(Op1, m_Xor(m_Value(A), m_Value(B)))) {
+    if (Op0 == A || Op0 == B)
+      return BinaryOperator::CreateOr(A, B);
+
+    if (match(Op0, m_And(m_Specific(A), m_Specific(B))) ||
+        match(Op0, m_And(m_Specific(B), m_Specific(A))))
+      return BinaryOperator::CreateOr(A, B);
+
+    if (Op1->hasOneUse() && match(A, m_Not(m_Specific(Op0)))) {
+      Value *Not = Builder->CreateNot(B, B->getName()+".not");
+      return BinaryOperator::CreateOr(Not, Op0);
+    }
+    if (Op1->hasOneUse() && match(B, m_Not(m_Specific(Op0)))) {
+      Value *Not = Builder->CreateNot(A, A->getName()+".not");
+      return BinaryOperator::CreateOr(Not, Op0);
+    }
+  }
+
+  // A | ~(A | B) -> A | ~B
+  // A | ~(A ^ B) -> A | ~B
+  if (match(Op1, m_Not(m_Value(A))))
+    if (BinaryOperator *B = dyn_cast<BinaryOperator>(A))
+      if ((Op0 == B->getOperand(0) || Op0 == B->getOperand(1)) &&
+          Op1->hasOneUse() && (B->getOpcode() == Instruction::Or ||
+                               B->getOpcode() == Instruction::Xor)) {
+        Value *NotOp = Op0 == B->getOperand(0) ? B->getOperand(1) :
+                                                 B->getOperand(0);
+        Value *Not = Builder->CreateNot(NotOp, NotOp->getName()+".not");
+        return BinaryOperator::CreateOr(Not, Op0);
+      }
+
+  // (A & B) | ((~A) ^ B) -> (~A ^ B)
+  if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
+      match(Op1, m_Xor(m_Not(m_Specific(A)), m_Specific(B))))
+    return BinaryOperator::CreateXor(Builder->CreateNot(A), B);
+
+  // ((~A) ^ B) | (A & B) -> (~A ^ B)
+  if (match(Op0, m_Xor(m_Not(m_Value(A)), m_Value(B))) &&
+      match(Op1, m_And(m_Specific(A), m_Specific(B))))
+    return BinaryOperator::CreateXor(Builder->CreateNot(A), B);
+
+  if (SwappedForXor)
+    std::swap(Op0, Op1);
+
+  {
+    ICmpInst *LHS = dyn_cast<ICmpInst>(Op0);
+    ICmpInst *RHS = dyn_cast<ICmpInst>(Op1);
+    if (LHS && RHS)
+      if (Value *Res = FoldOrOfICmps(LHS, RHS, &I))
+        return ReplaceInstUsesWith(I, Res);
+
+    // TODO: Make this recursive; it's a little tricky because an arbitrary
+    // number of 'or' instructions might have to be created.
+    Value *X, *Y;
+    if (LHS && match(Op1, m_OneUse(m_Or(m_Value(X), m_Value(Y))))) {
+      if (auto *Cmp = dyn_cast<ICmpInst>(X))
+        if (Value *Res = FoldOrOfICmps(LHS, Cmp, &I))
+          return ReplaceInstUsesWith(I, Builder->CreateOr(Res, Y));
+      if (auto *Cmp = dyn_cast<ICmpInst>(Y))
+        if (Value *Res = FoldOrOfICmps(LHS, Cmp, &I))
+          return ReplaceInstUsesWith(I, Builder->CreateOr(Res, X));
+    }
+    if (RHS && match(Op0, m_OneUse(m_Or(m_Value(X), m_Value(Y))))) {
+      if (auto *Cmp = dyn_cast<ICmpInst>(X))
+        if (Value *Res = FoldOrOfICmps(Cmp, RHS, &I))
+          return ReplaceInstUsesWith(I, Builder->CreateOr(Res, Y));
+      if (auto *Cmp = dyn_cast<ICmpInst>(Y))
+        if (Value *Res = FoldOrOfICmps(Cmp, RHS, &I))
+          return ReplaceInstUsesWith(I, Builder->CreateOr(Res, X));
+    }
+  }
+
+  // (fcmp uno x, c) | (fcmp uno y, c)  -> (fcmp uno x, y)
+  if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0)))
+    if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1)))
+      if (Value *Res = FoldOrOfFCmps(LHS, RHS))
+        return ReplaceInstUsesWith(I, Res);
+
+  // fold (or (cast A), (cast B)) -> (cast (or A, B))
+  if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
+    CastInst *Op1C = dyn_cast<CastInst>(Op1);
+    if (Op1C && Op0C->getOpcode() == Op1C->getOpcode()) {// same cast kind ?
+      Type *SrcTy = Op0C->getOperand(0)->getType();
+      if (SrcTy == Op1C->getOperand(0)->getType() &&
+          SrcTy->isIntOrIntVectorTy()) {
+        Value *Op0COp = Op0C->getOperand(0), *Op1COp = Op1C->getOperand(0);
+
+        if ((!isa<ICmpInst>(Op0COp) || !isa<ICmpInst>(Op1COp)) &&
+            // Only do this if the casts both really cause code to be
+            // generated.
+            ShouldOptimizeCast(Op0C->getOpcode(), Op0COp, I.getType()) &&
+            ShouldOptimizeCast(Op1C->getOpcode(), Op1COp, I.getType())) {
+          Value *NewOp = Builder->CreateOr(Op0COp, Op1COp, I.getName());
+          return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType());
+        }
+
+        // If this is or(cast(icmp), cast(icmp)), try to fold this even if the
+        // cast is otherwise not optimizable.  This happens for vector sexts.
+        if (ICmpInst *RHS = dyn_cast<ICmpInst>(Op1COp))
+          if (ICmpInst *LHS = dyn_cast<ICmpInst>(Op0COp))
+            if (Value *Res = FoldOrOfICmps(LHS, RHS, &I))
+              return CastInst::Create(Op0C->getOpcode(), Res, I.getType());
+
+        // If this is or(cast(fcmp), cast(fcmp)), try to fold this even if the
+        // cast is otherwise not optimizable.  This happens for vector sexts.
+        if (FCmpInst *RHS = dyn_cast<FCmpInst>(Op1COp))
+          if (FCmpInst *LHS = dyn_cast<FCmpInst>(Op0COp))
+            if (Value *Res = FoldOrOfFCmps(LHS, RHS))
+              return CastInst::Create(Op0C->getOpcode(), Res, I.getType());
+      }
+    }
+  }
+
+  // or(sext(A), B) -> A ? -1 : B where A is an i1
+  // or(A, sext(B)) -> B ? -1 : A where B is an i1
+  if (match(Op0, m_SExt(m_Value(A))) && A->getType()->isIntegerTy(1))
+    return SelectInst::Create(A, ConstantInt::getSigned(I.getType(), -1), Op1);
+  if (match(Op1, m_SExt(m_Value(A))) && A->getType()->isIntegerTy(1))
+    return SelectInst::Create(A, ConstantInt::getSigned(I.getType(), -1), Op0);
+
+  // Note: If we've gotten to the point of visiting the outer OR, then the
+  // inner one couldn't be simplified.  If it was a constant, then it won't
+  // be simplified by a later pass either, so we try swapping the inner/outer
+  // ORs in the hopes that we'll be able to simplify it this way.
+  // (X|C) | V --> (X|V) | C
+  if (Op0->hasOneUse() && !isa<ConstantInt>(Op1) &&
+      match(Op0, m_Or(m_Value(A), m_ConstantInt(C1)))) {
+    Value *Inner = Builder->CreateOr(A, Op1);
+    Inner->takeName(Op0);
+    return BinaryOperator::CreateOr(Inner, C1);
+  }
+
+  // Change (or (bool?A:B),(bool?C:D)) --> (bool?(or A,C):(or B,D))
+  // Since this OR statement hasn't been optimized further yet, we hope
+  // that this transformation will allow the new ORs to be optimized.
+  {
+    Value *X = nullptr, *Y = nullptr;
+    if (Op0->hasOneUse() && Op1->hasOneUse() &&
+        match(Op0, m_Select(m_Value(X), m_Value(A), m_Value(B))) &&
+        match(Op1, m_Select(m_Value(Y), m_Value(C), m_Value(D))) && X == Y) {
+      Value *orTrue = Builder->CreateOr(A, C);
+      Value *orFalse = Builder->CreateOr(B, D);
+      return SelectInst::Create(X, orTrue, orFalse);
+    }
+  }
+
+  return Changed ? &I : nullptr;
+}
+
+Instruction *InstCombiner::visitXor(BinaryOperator &I) {
+  bool Changed = SimplifyAssociativeOrCommutative(I);
+  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+
+  if (Value *V = SimplifyVectorOp(I))
+    return ReplaceInstUsesWith(I, V);
+
+  if (Value *V = SimplifyXorInst(Op0, Op1, DL, TLI, DT, AC))
+    return ReplaceInstUsesWith(I, V);
+
+  // (A&B)^(A&C) -> A&(B^C) etc
+  if (Value *V = SimplifyUsingDistributiveLaws(I))
+    return ReplaceInstUsesWith(I, V);
+
+  // See if we can simplify any instructions used by the instruction whose sole
+  // purpose is to compute bits we don't care about.
+  if (SimplifyDemandedInstructionBits(I))
+    return &I;
+
+  if (Value *V = SimplifyBSwap(I))
+    return ReplaceInstUsesWith(I, V);
+
+  // Is this a ~ operation?
+  if (Value *NotOp = dyn_castNotVal(&I)) {
+    if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(NotOp)) {
+      if (Op0I->getOpcode() == Instruction::And ||
+          Op0I->getOpcode() == Instruction::Or) {
+        // ~(~X & Y) --> (X | ~Y) - De Morgan's Law
+        // ~(~X | Y) === (X & ~Y) - De Morgan's Law
+        if (dyn_castNotVal(Op0I->getOperand(1)))
+          Op0I->swapOperands();
+        if (Value *Op0NotVal = dyn_castNotVal(Op0I->getOperand(0))) {
+          Value *NotY =
+            Builder->CreateNot(Op0I->getOperand(1),
+                               Op0I->getOperand(1)->getName()+".not");
+          if (Op0I->getOpcode() == Instruction::And)
+            return BinaryOperator::CreateOr(Op0NotVal, NotY);
+          return BinaryOperator::CreateAnd(Op0NotVal, NotY);
+        }
+
+        // ~(X & Y) --> (~X | ~Y) - De Morgan's Law
+        // ~(X | Y) === (~X & ~Y) - De Morgan's Law
+        if (IsFreeToInvert(Op0I->getOperand(0),
+                           Op0I->getOperand(0)->hasOneUse()) &&
+            IsFreeToInvert(Op0I->getOperand(1),
+                           Op0I->getOperand(1)->hasOneUse())) {
+          Value *NotX =
+            Builder->CreateNot(Op0I->getOperand(0), "notlhs");
+          Value *NotY =
+            Builder->CreateNot(Op0I->getOperand(1), "notrhs");
+          if (Op0I->getOpcode() == Instruction::And)
+            return BinaryOperator::CreateOr(NotX, NotY);
+          return BinaryOperator::CreateAnd(NotX, NotY);
+        }
+
+      } else if (Op0I->getOpcode() == Instruction::AShr) {
+        // ~(~X >>s Y) --> (X >>s Y)
+        if (Value *Op0NotVal = dyn_castNotVal(Op0I->getOperand(0)))
+          return BinaryOperator::CreateAShr(Op0NotVal, Op0I->getOperand(1));
+      }
+    }
+  }
+
+  if (Constant *RHS = dyn_cast<Constant>(Op1)) {
+    if (RHS->isAllOnesValue() && Op0->hasOneUse())
+      // xor (cmp A, B), true = not (cmp A, B) = !cmp A, B
+      if (CmpInst *CI = dyn_cast<CmpInst>(Op0))
+        return CmpInst::Create(CI->getOpcode(),
+                               CI->getInversePredicate(),
+                               CI->getOperand(0), CI->getOperand(1));
+  }
+
+  if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
+    // fold (xor(zext(cmp)), 1) and (xor(sext(cmp)), -1) to ext(!cmp).
+    if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
+      if (CmpInst *CI = dyn_cast<CmpInst>(Op0C->getOperand(0))) {
+        if (CI->hasOneUse() && Op0C->hasOneUse()) {
+          Instruction::CastOps Opcode = Op0C->getOpcode();
+          if ((Opcode == Instruction::ZExt || Opcode == Instruction::SExt) &&
+              (RHS == ConstantExpr::getCast(Opcode, Builder->getTrue(),
+                                            Op0C->getDestTy()))) {
+            CI->setPredicate(CI->getInversePredicate());
+            return CastInst::Create(Opcode, CI, Op0C->getType());
+          }
+        }
+      }
+    }
+
+    if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
+      // ~(c-X) == X-c-1 == X+(-c-1)
+      if (Op0I->getOpcode() == Instruction::Sub && RHS->isAllOnesValue())
+        if (Constant *Op0I0C = dyn_cast<Constant>(Op0I->getOperand(0))) {
+          Constant *NegOp0I0C = ConstantExpr::getNeg(Op0I0C);
+          Constant *ConstantRHS = ConstantExpr::getSub(NegOp0I0C,
+                                      ConstantInt::get(I.getType(), 1));
+          return BinaryOperator::CreateAdd(Op0I->getOperand(1), ConstantRHS);
+        }
+
+      if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) {
+        if (Op0I->getOpcode() == Instruction::Add) {
+          // ~(X-c) --> (-c-1)-X
+          if (RHS->isAllOnesValue()) {
+            Constant *NegOp0CI = ConstantExpr::getNeg(Op0CI);
+            return BinaryOperator::CreateSub(
+                           ConstantExpr::getSub(NegOp0CI,
+                                      ConstantInt::get(I.getType(), 1)),
+                                      Op0I->getOperand(0));
+          } else if (RHS->getValue().isSignBit()) {
+            // (X + C) ^ signbit -> (X + C + signbit)
+            Constant *C = Builder->getInt(RHS->getValue() + Op0CI->getValue());
+            return BinaryOperator::CreateAdd(Op0I->getOperand(0), C);
+
+          }
+        } else if (Op0I->getOpcode() == Instruction::Or) {
+          // (X|C1)^C2 -> X^(C1|C2) iff X&~C1 == 0
+          if (MaskedValueIsZero(Op0I->getOperand(0), Op0CI->getValue(),
+                                0, &I)) {
+            Constant *NewRHS = ConstantExpr::getOr(Op0CI, RHS);
+            // Anything in both C1 and C2 is known to be zero, remove it from
+            // NewRHS.
+            Constant *CommonBits = ConstantExpr::getAnd(Op0CI, RHS);
+            NewRHS = ConstantExpr::getAnd(NewRHS,
+                                       ConstantExpr::getNot(CommonBits));
+            Worklist.Add(Op0I);
+            I.setOperand(0, Op0I->getOperand(0));
+            I.setOperand(1, NewRHS);
+            return &I;
+          }
+        } else if (Op0I->getOpcode() == Instruction::LShr) {
+          // ((X^C1) >> C2) ^ C3 -> (X>>C2) ^ ((C1>>C2)^C3)
+          // E1 = "X ^ C1"
+          BinaryOperator *E1;
+          ConstantInt *C1;
+          if (Op0I->hasOneUse() &&
+              (E1 = dyn_cast<BinaryOperator>(Op0I->getOperand(0))) &&
+              E1->getOpcode() == Instruction::Xor &&
+              (C1 = dyn_cast<ConstantInt>(E1->getOperand(1)))) {
+            // fold (C1 >> C2) ^ C3
+            ConstantInt *C2 = Op0CI, *C3 = RHS;
+            APInt FoldConst = C1->getValue().lshr(C2->getValue());
+            FoldConst ^= C3->getValue();
+            // Prepare the two operands.
+            Value *Opnd0 = Builder->CreateLShr(E1->getOperand(0), C2);
+            Opnd0->takeName(Op0I);
+            cast<Instruction>(Opnd0)->setDebugLoc(I.getDebugLoc());
+            Value *FoldVal = ConstantInt::get(Opnd0->getType(), FoldConst);
+
+            return BinaryOperator::CreateXor(Opnd0, FoldVal);
+          }
+        }
+      }
+    }
+
+    // Try to fold constant and into select arguments.
+    if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
+      if (Instruction *R = FoldOpIntoSelect(I, SI))
+        return R;
+    if (isa<PHINode>(Op0))
+      if (Instruction *NV = FoldOpIntoPhi(I))
+        return NV;
+  }
+
+  BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1);
+  if (Op1I) {
+    Value *A, *B;
+    if (match(Op1I, m_Or(m_Value(A), m_Value(B)))) {
+      if (A == Op0) {              // B^(B|A) == (A|B)^B
+        Op1I->swapOperands();
+        I.swapOperands();
+        std::swap(Op0, Op1);
+      } else if (B == Op0) {       // B^(A|B) == (A|B)^B
+        I.swapOperands();     // Simplified below.
+        std::swap(Op0, Op1);
+      }
+    } else if (match(Op1I, m_And(m_Value(A), m_Value(B))) &&
+               Op1I->hasOneUse()){
+      if (A == Op0) {                                      // A^(A&B) -> A^(B&A)
+        Op1I->swapOperands();
+        std::swap(A, B);
+      }
+      if (B == Op0) {                                      // A^(B&A) -> (B&A)^A
+        I.swapOperands();     // Simplified below.
+        std::swap(Op0, Op1);
+      }
+    }
+  }
+
+  BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0);
+  if (Op0I) {
+    Value *A, *B;
+    if (match(Op0I, m_Or(m_Value(A), m_Value(B))) &&
+        Op0I->hasOneUse()) {
+      if (A == Op1)                                  // (B|A)^B == (A|B)^B
+        std::swap(A, B);
+      if (B == Op1)                                  // (A|B)^B == A & ~B
+        return BinaryOperator::CreateAnd(A, Builder->CreateNot(Op1));
+    } else if (match(Op0I, m_And(m_Value(A), m_Value(B))) &&
+               Op0I->hasOneUse()){
+      if (A == Op1)                                        // (A&B)^A -> (B&A)^A
+        std::swap(A, B);
+      if (B == Op1 &&                                      // (B&A)^A == ~B & A
+          !isa<ConstantInt>(Op1)) {  // Canonical form is (B&C)^C
+        return BinaryOperator::CreateAnd(Builder->CreateNot(A), Op1);
+      }
+    }
+  }
+
+  if (Op0I && Op1I) {
+    Value *A, *B, *C, *D;
+    // (A & B)^(A | B) -> A ^ B
+    if (match(Op0I, m_And(m_Value(A), m_Value(B))) &&
+        match(Op1I, m_Or(m_Value(C), m_Value(D)))) {
+      if ((A == C && B == D) || (A == D && B == C))
+        return BinaryOperator::CreateXor(A, B);
+    }
+    // (A | B)^(A & B) -> A ^ B
+    if (match(Op0I, m_Or(m_Value(A), m_Value(B))) &&
+        match(Op1I, m_And(m_Value(C), m_Value(D)))) {
+      if ((A == C && B == D) || (A == D && B == C))
+        return BinaryOperator::CreateXor(A, B);
+    }
+    // (A | ~B) ^ (~A | B) -> A ^ B
+    if (match(Op0I, m_Or(m_Value(A), m_Not(m_Value(B)))) &&
+        match(Op1I, m_Or(m_Not(m_Specific(A)), m_Specific(B)))) {
+      return BinaryOperator::CreateXor(A, B);
+    }
+    // (~A | B) ^ (A | ~B) -> A ^ B
+    if (match(Op0I, m_Or(m_Not(m_Value(A)), m_Value(B))) &&
+        match(Op1I, m_Or(m_Specific(A), m_Not(m_Specific(B))))) {
+      return BinaryOperator::CreateXor(A, B);
+    }
+    // (A & ~B) ^ (~A & B) -> A ^ B
+    if (match(Op0I, m_And(m_Value(A), m_Not(m_Value(B)))) &&
+        match(Op1I, m_And(m_Not(m_Specific(A)), m_Specific(B)))) {
+      return BinaryOperator::CreateXor(A, B);
+    }
+    // (~A & B) ^ (A & ~B) -> A ^ B
+    if (match(Op0I, m_And(m_Not(m_Value(A)), m_Value(B))) &&
+        match(Op1I, m_And(m_Specific(A), m_Not(m_Specific(B))))) {
+      return BinaryOperator::CreateXor(A, B);
+    }
+    // (A ^ C)^(A | B) -> ((~A) & B) ^ C
+    if (match(Op0I, m_Xor(m_Value(D), m_Value(C))) &&
+        match(Op1I, m_Or(m_Value(A), m_Value(B)))) {
+      if (D == A)
+        return BinaryOperator::CreateXor(
+            Builder->CreateAnd(Builder->CreateNot(A), B), C);
+      if (D == B)
+        return BinaryOperator::CreateXor(
+            Builder->CreateAnd(Builder->CreateNot(B), A), C);
+    }
+    // (A | B)^(A ^ C) -> ((~A) & B) ^ C
+    if (match(Op0I, m_Or(m_Value(A), m_Value(B))) &&
+        match(Op1I, m_Xor(m_Value(D), m_Value(C)))) {
+      if (D == A)
+        return BinaryOperator::CreateXor(
+            Builder->CreateAnd(Builder->CreateNot(A), B), C);
+      if (D == B)
+        return BinaryOperator::CreateXor(
+            Builder->CreateAnd(Builder->CreateNot(B), A), C);
+    }
+    // (A & B) ^ (A ^ B) -> (A | B)
+    if (match(Op0I, m_And(m_Value(A), m_Value(B))) &&
+        match(Op1I, m_Xor(m_Specific(A), m_Specific(B))))
+      return BinaryOperator::CreateOr(A, B);
+    // (A ^ B) ^ (A & B) -> (A | B)
+    if (match(Op0I, m_Xor(m_Value(A), m_Value(B))) &&
+        match(Op1I, m_And(m_Specific(A), m_Specific(B))))
+      return BinaryOperator::CreateOr(A, B);
+  }
+
+  Value *A = nullptr, *B = nullptr;
+  // (A & ~B) ^ (~A) -> ~(A & B)
+  if (match(Op0, m_And(m_Value(A), m_Not(m_Value(B)))) &&
+      match(Op1, m_Not(m_Specific(A))))
+    return BinaryOperator::CreateNot(Builder->CreateAnd(A, B));
+
+  // (icmp1 A, B) ^ (icmp2 A, B) --> (icmp3 A, B)
+  if (ICmpInst *RHS = dyn_cast<ICmpInst>(I.getOperand(1)))
+    if (ICmpInst *LHS = dyn_cast<ICmpInst>(I.getOperand(0)))
+      if (PredicatesFoldable(LHS->getPredicate(), RHS->getPredicate())) {
+        if (LHS->getOperand(0) == RHS->getOperand(1) &&
+            LHS->getOperand(1) == RHS->getOperand(0))
+          LHS->swapOperands();
+        if (LHS->getOperand(0) == RHS->getOperand(0) &&
+            LHS->getOperand(1) == RHS->getOperand(1)) {
+          Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
+          unsigned Code = getICmpCode(LHS) ^ getICmpCode(RHS);
+          bool isSigned = LHS->isSigned() || RHS->isSigned();
+          return ReplaceInstUsesWith(I,
+                               getNewICmpValue(isSigned, Code, Op0, Op1,
+                                               Builder));
+        }
+      }
+
+  // fold (xor (cast A), (cast B)) -> (cast (xor A, B))
+  if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
+    if (CastInst *Op1C = dyn_cast<CastInst>(Op1))
+      if (Op0C->getOpcode() == Op1C->getOpcode()) { // same cast kind?
+        Type *SrcTy = Op0C->getOperand(0)->getType();
+        if (SrcTy == Op1C->getOperand(0)->getType() && SrcTy->isIntegerTy() &&
+            // Only do this if the casts both really cause code to be generated.
+            ShouldOptimizeCast(Op0C->getOpcode(), Op0C->getOperand(0),
+                               I.getType()) &&
+            ShouldOptimizeCast(Op1C->getOpcode(), Op1C->getOperand(0),
+                               I.getType())) {
+          Value *NewOp = Builder->CreateXor(Op0C->getOperand(0),
+                                            Op1C->getOperand(0), I.getName());
+          return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType());
+        }
+      }
+  }
+
+  return Changed ? &I : nullptr;
+}