Remove LLVM 8.0.1 files.

1 files changed, 0 insertions, 823 deletions

diff --git a/gnu/llvm/lib/Analysis/LoopInfo.cpp b/gnu/llvm/lib/Analysis/LoopInfo.cpp
deleted file mode 100644
index ef2b1257015..00000000000
--- a/gnu/llvm/lib/Analysis/LoopInfo.cpp
+++ /dev/null
@@ -1,823 +0,0 @@
-//===- LoopInfo.cpp - Natural Loop Calculator -----------------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file defines the LoopInfo class that is used to identify natural loops
-// and determine the loop depth of various nodes of the CFG.  Note that the
-// loops identified may actually be several natural loops that share the same
-// header node... not just a single natural loop.
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Analysis/LoopInfo.h"
-#include "llvm/ADT/DepthFirstIterator.h"
-#include "llvm/ADT/ScopeExit.h"
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/Analysis/LoopInfoImpl.h"
-#include "llvm/Analysis/LoopIterator.h"
-#include "llvm/Analysis/ValueTracking.h"
-#include "llvm/Config/llvm-config.h"
-#include "llvm/IR/CFG.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/DebugLoc.h"
-#include "llvm/IR/Dominators.h"
-#include "llvm/IR/IRPrintingPasses.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/LLVMContext.h"
-#include "llvm/IR/Metadata.h"
-#include "llvm/IR/PassManager.h"
-#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/raw_ostream.h"
-#include <algorithm>
-using namespace llvm;
-
-// Explicitly instantiate methods in LoopInfoImpl.h for IR-level Loops.
-template class llvm::LoopBase<BasicBlock, Loop>;
-template class llvm::LoopInfoBase<BasicBlock, Loop>;
-
-// Always verify loopinfo if expensive checking is enabled.
-#ifdef EXPENSIVE_CHECKS
-bool llvm::VerifyLoopInfo = true;
-#else
-bool llvm::VerifyLoopInfo = false;
-#endif
-static cl::opt<bool, true>
-    VerifyLoopInfoX("verify-loop-info", cl::location(VerifyLoopInfo),
-                    cl::Hidden, cl::desc("Verify loop info (time consuming)"));
-
-//===----------------------------------------------------------------------===//
-// Loop implementation
-//
-
-bool Loop::isLoopInvariant(const Value *V) const {
-  if (const Instruction *I = dyn_cast<Instruction>(V))
-    return !contains(I);
-  return true; // All non-instructions are loop invariant
-}
-
-bool Loop::hasLoopInvariantOperands(const Instruction *I) const {
-  return all_of(I->operands(), [this](Value *V) { return isLoopInvariant(V); });
-}
-
-bool Loop::makeLoopInvariant(Value *V, bool &Changed,
-                             Instruction *InsertPt) const {
-  if (Instruction *I = dyn_cast<Instruction>(V))
-    return makeLoopInvariant(I, Changed, InsertPt);
-  return true; // All non-instructions are loop-invariant.
-}
-
-bool Loop::makeLoopInvariant(Instruction *I, bool &Changed,
-                             Instruction *InsertPt) const {
-  // Test if the value is already loop-invariant.
-  if (isLoopInvariant(I))
-    return true;
-  if (!isSafeToSpeculativelyExecute(I))
-    return false;
-  if (I->mayReadFromMemory())
-    return false;
-  // EH block instructions are immobile.
-  if (I->isEHPad())
-    return false;
-  // Determine the insertion point, unless one was given.
-  if (!InsertPt) {
-    BasicBlock *Preheader = getLoopPreheader();
-    // Without a preheader, hoisting is not feasible.
-    if (!Preheader)
-      return false;
-    InsertPt = Preheader->getTerminator();
-  }
-  // Don't hoist instructions with loop-variant operands.
-  for (Value *Operand : I->operands())
-    if (!makeLoopInvariant(Operand, Changed, InsertPt))
-      return false;
-
-  // Hoist.
-  I->moveBefore(InsertPt);
-
-  // There is possibility of hoisting this instruction above some arbitrary
-  // condition. Any metadata defined on it can be control dependent on this
-  // condition. Conservatively strip it here so that we don't give any wrong
-  // information to the optimizer.
-  I->dropUnknownNonDebugMetadata();
-
-  Changed = true;
-  return true;
-}
-
-PHINode *Loop::getCanonicalInductionVariable() const {
-  BasicBlock *H = getHeader();
-
-  BasicBlock *Incoming = nullptr, *Backedge = nullptr;
-  pred_iterator PI = pred_begin(H);
-  assert(PI != pred_end(H) && "Loop must have at least one backedge!");
-  Backedge = *PI++;
-  if (PI == pred_end(H))
-    return nullptr; // dead loop
-  Incoming = *PI++;
-  if (PI != pred_end(H))
-    return nullptr; // multiple backedges?
-
-  if (contains(Incoming)) {
-    if (contains(Backedge))
-      return nullptr;
-    std::swap(Incoming, Backedge);
-  } else if (!contains(Backedge))
-    return nullptr;
-
-  // Loop over all of the PHI nodes, looking for a canonical indvar.
-  for (BasicBlock::iterator I = H->begin(); isa<PHINode>(I); ++I) {
-    PHINode *PN = cast<PHINode>(I);
-    if (ConstantInt *CI =
-            dyn_cast<ConstantInt>(PN->getIncomingValueForBlock(Incoming)))
-      if (CI->isZero())
-        if (Instruction *Inc =
-                dyn_cast<Instruction>(PN->getIncomingValueForBlock(Backedge)))
-          if (Inc->getOpcode() == Instruction::Add && Inc->getOperand(0) == PN)
-            if (ConstantInt *CI = dyn_cast<ConstantInt>(Inc->getOperand(1)))
-              if (CI->isOne())
-                return PN;
-  }
-  return nullptr;
-}
-
-// Check that 'BB' doesn't have any uses outside of the 'L'
-static bool isBlockInLCSSAForm(const Loop &L, const BasicBlock &BB,
-                               DominatorTree &DT) {
-  for (const Instruction &I : BB) {
-    // Tokens can't be used in PHI nodes and live-out tokens prevent loop
-    // optimizations, so for the purposes of considered LCSSA form, we
-    // can ignore them.
-    if (I.getType()->isTokenTy())
-      continue;
-
-    for (const Use &U : I.uses()) {
-      const Instruction *UI = cast<Instruction>(U.getUser());
-      const BasicBlock *UserBB = UI->getParent();
-      if (const PHINode *P = dyn_cast<PHINode>(UI))
-        UserBB = P->getIncomingBlock(U);
-
-      // Check the current block, as a fast-path, before checking whether
-      // the use is anywhere in the loop.  Most values are used in the same
-      // block they are defined in.  Also, blocks not reachable from the
-      // entry are special; uses in them don't need to go through PHIs.
-      if (UserBB != &BB && !L.contains(UserBB) &&
-          DT.isReachableFromEntry(UserBB))
-        return false;
-    }
-  }
-  return true;
-}
-
-bool Loop::isLCSSAForm(DominatorTree &DT) const {
-  // For each block we check that it doesn't have any uses outside of this loop.
-  return all_of(this->blocks(), [&](const BasicBlock *BB) {
-    return isBlockInLCSSAForm(*this, *BB, DT);
-  });
-}
-
-bool Loop::isRecursivelyLCSSAForm(DominatorTree &DT, const LoopInfo &LI) const {
-  // For each block we check that it doesn't have any uses outside of its
-  // innermost loop. This process will transitively guarantee that the current
-  // loop and all of the nested loops are in LCSSA form.
-  return all_of(this->blocks(), [&](const BasicBlock *BB) {
-    return isBlockInLCSSAForm(*LI.getLoopFor(BB), *BB, DT);
-  });
-}
-
-bool Loop::isLoopSimplifyForm() const {
-  // Normal-form loops have a preheader, a single backedge, and all of their
-  // exits have all their predecessors inside the loop.
-  return getLoopPreheader() && getLoopLatch() && hasDedicatedExits();
-}
-
-// Routines that reform the loop CFG and split edges often fail on indirectbr.
-bool Loop::isSafeToClone() const {
-  // Return false if any loop blocks contain indirectbrs, or there are any calls
-  // to noduplicate functions.
-  for (BasicBlock *BB : this->blocks()) {
-    if (isa<IndirectBrInst>(BB->getTerminator()))
-      return false;
-
-    for (Instruction &I : *BB)
-      if (auto CS = CallSite(&I))
-        if (CS.cannotDuplicate())
-          return false;
-  }
-  return true;
-}
-
-MDNode *Loop::getLoopID() const {
-  MDNode *LoopID = nullptr;
-
-  // Go through the latch blocks and check the terminator for the metadata.
-  SmallVector<BasicBlock *, 4> LatchesBlocks;
-  getLoopLatches(LatchesBlocks);
-  for (BasicBlock *BB : LatchesBlocks) {
-    Instruction *TI = BB->getTerminator();
-    MDNode *MD = TI->getMetadata(LLVMContext::MD_loop);
-
-    if (!MD)
-      return nullptr;
-
-    if (!LoopID)
-      LoopID = MD;
-    else if (MD != LoopID)
-      return nullptr;
-  }
-  if (!LoopID || LoopID->getNumOperands() == 0 ||
-      LoopID->getOperand(0) != LoopID)
-    return nullptr;
-  return LoopID;
-}
-
-void Loop::setLoopID(MDNode *LoopID) const {
-  assert((!LoopID || LoopID->getNumOperands() > 0) &&
-         "Loop ID needs at least one operand");
-  assert((!LoopID || LoopID->getOperand(0) == LoopID) &&
-         "Loop ID should refer to itself");
-
-  BasicBlock *H = getHeader();
-  for (BasicBlock *BB : this->blocks()) {
-    Instruction *TI = BB->getTerminator();
-    for (BasicBlock *Successor : successors(TI)) {
-      if (Successor == H) {
-        TI->setMetadata(LLVMContext::MD_loop, LoopID);
-        break;
-      }
-    }
-  }
-}
-
-void Loop::setLoopAlreadyUnrolled() {
-  MDNode *LoopID = getLoopID();
-  // First remove any existing loop unrolling metadata.
-  SmallVector<Metadata *, 4> MDs;
-  // Reserve first location for self reference to the LoopID metadata node.
-  MDs.push_back(nullptr);
-
-  if (LoopID) {
-    for (unsigned i = 1, ie = LoopID->getNumOperands(); i < ie; ++i) {
-      bool IsUnrollMetadata = false;
-      MDNode *MD = dyn_cast<MDNode>(LoopID->getOperand(i));
-      if (MD) {
-        const MDString *S = dyn_cast<MDString>(MD->getOperand(0));
-        IsUnrollMetadata = S && S->getString().startswith("llvm.loop.unroll.");
-      }
-      if (!IsUnrollMetadata)
-        MDs.push_back(LoopID->getOperand(i));
-    }
-  }
-
-  // Add unroll(disable) metadata to disable future unrolling.
-  LLVMContext &Context = getHeader()->getContext();
-  SmallVector<Metadata *, 1> DisableOperands;
-  DisableOperands.push_back(MDString::get(Context, "llvm.loop.unroll.disable"));
-  MDNode *DisableNode = MDNode::get(Context, DisableOperands);
-  MDs.push_back(DisableNode);
-
-  MDNode *NewLoopID = MDNode::get(Context, MDs);
-  // Set operand 0 to refer to the loop id itself.
-  NewLoopID->replaceOperandWith(0, NewLoopID);
-  setLoopID(NewLoopID);
-}
-
-bool Loop::isAnnotatedParallel() const {
-  MDNode *DesiredLoopIdMetadata = getLoopID();
-
-  if (!DesiredLoopIdMetadata)
-    return false;
-
-  MDNode *ParallelAccesses =
-      findOptionMDForLoop(this, "llvm.loop.parallel_accesses");
-  SmallPtrSet<MDNode *, 4>
-      ParallelAccessGroups; // For scalable 'contains' check.
-  if (ParallelAccesses) {
-    for (const MDOperand &MD : drop_begin(ParallelAccesses->operands(), 1)) {
-      MDNode *AccGroup = cast<MDNode>(MD.get());
-      assert(isValidAsAccessGroup(AccGroup) &&
-             "List item must be an access group");
-      ParallelAccessGroups.insert(AccGroup);
-    }
-  }
-
-  // The loop branch contains the parallel loop metadata. In order to ensure
-  // that any parallel-loop-unaware optimization pass hasn't added loop-carried
-  // dependencies (thus converted the loop back to a sequential loop), check
-  // that all the memory instructions in the loop belong to an access group that
-  // is parallel to this loop.
-  for (BasicBlock *BB : this->blocks()) {
-    for (Instruction &I : *BB) {
-      if (!I.mayReadOrWriteMemory())
-        continue;
-
-      if (MDNode *AccessGroup = I.getMetadata(LLVMContext::MD_access_group)) {
-        auto ContainsAccessGroup = [&ParallelAccessGroups](MDNode *AG) -> bool {
-          if (AG->getNumOperands() == 0) {
-            assert(isValidAsAccessGroup(AG) && "Item must be an access group");
-            return ParallelAccessGroups.count(AG);
-          }
-
-          for (const MDOperand &AccessListItem : AG->operands()) {
-            MDNode *AccGroup = cast<MDNode>(AccessListItem.get());
-            assert(isValidAsAccessGroup(AccGroup) &&
-                   "List item must be an access group");
-            if (ParallelAccessGroups.count(AccGroup))
-              return true;
-          }
-          return false;
-        };
-
-        if (ContainsAccessGroup(AccessGroup))
-          continue;
-      }
-
-      // The memory instruction can refer to the loop identifier metadata
-      // directly or indirectly through another list metadata (in case of
-      // nested parallel loops). The loop identifier metadata refers to
-      // itself so we can check both cases with the same routine.
-      MDNode *LoopIdMD =
-          I.getMetadata(LLVMContext::MD_mem_parallel_loop_access);
-
-      if (!LoopIdMD)
-        return false;
-
-      bool LoopIdMDFound = false;
-      for (const MDOperand &MDOp : LoopIdMD->operands()) {
-        if (MDOp == DesiredLoopIdMetadata) {
-          LoopIdMDFound = true;
-          break;
-        }
-      }
-
-      if (!LoopIdMDFound)
-        return false;
-    }
-  }
-  return true;
-}
-
-DebugLoc Loop::getStartLoc() const { return getLocRange().getStart(); }
-
-Loop::LocRange Loop::getLocRange() const {
-  // If we have a debug location in the loop ID, then use it.
-  if (MDNode *LoopID = getLoopID()) {
-    DebugLoc Start;
-    // We use the first DebugLoc in the header as the start location of the loop
-    // and if there is a second DebugLoc in the header we use it as end location
-    // of the loop.
-    for (unsigned i = 1, ie = LoopID->getNumOperands(); i < ie; ++i) {
-      if (DILocation *L = dyn_cast<DILocation>(LoopID->getOperand(i))) {
-        if (!Start)
-          Start = DebugLoc(L);
-        else
-          return LocRange(Start, DebugLoc(L));
-      }
-    }
-
-    if (Start)
-      return LocRange(Start);
-  }
-
-  // Try the pre-header first.
-  if (BasicBlock *PHeadBB = getLoopPreheader())
-    if (DebugLoc DL = PHeadBB->getTerminator()->getDebugLoc())
-      return LocRange(DL);
-
-  // If we have no pre-header or there are no instructions with debug
-  // info in it, try the header.
-  if (BasicBlock *HeadBB = getHeader())
-    return LocRange(HeadBB->getTerminator()->getDebugLoc());
-
-  return LocRange();
-}
-
-#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
-LLVM_DUMP_METHOD void Loop::dump() const { print(dbgs()); }
-
-LLVM_DUMP_METHOD void Loop::dumpVerbose() const {
-  print(dbgs(), /*Depth=*/0, /*Verbose=*/true);
-}
-#endif
-
-//===----------------------------------------------------------------------===//
-// UnloopUpdater implementation
-//
-
-namespace {
-/// Find the new parent loop for all blocks within the "unloop" whose last
-/// backedges has just been removed.
-class UnloopUpdater {
-  Loop &Unloop;
-  LoopInfo *LI;
-
-  LoopBlocksDFS DFS;
-
-  // Map unloop's immediate subloops to their nearest reachable parents. Nested
-  // loops within these subloops will not change parents. However, an immediate
-  // subloop's new parent will be the nearest loop reachable from either its own
-  // exits *or* any of its nested loop's exits.
-  DenseMap<Loop *, Loop *> SubloopParents;
-
-  // Flag the presence of an irreducible backedge whose destination is a block
-  // directly contained by the original unloop.
-  bool FoundIB;
-
-public:
-  UnloopUpdater(Loop *UL, LoopInfo *LInfo)
-      : Unloop(*UL), LI(LInfo), DFS(UL), FoundIB(false) {}
-
-  void updateBlockParents();
-
-  void removeBlocksFromAncestors();
-
-  void updateSubloopParents();
-
-protected:
-  Loop *getNearestLoop(BasicBlock *BB, Loop *BBLoop);
-};
-} // end anonymous namespace
-
-/// Update the parent loop for all blocks that are directly contained within the
-/// original "unloop".
-void UnloopUpdater::updateBlockParents() {
-  if (Unloop.getNumBlocks()) {
-    // Perform a post order CFG traversal of all blocks within this loop,
-    // propagating the nearest loop from successors to predecessors.
-    LoopBlocksTraversal Traversal(DFS, LI);
-    for (BasicBlock *POI : Traversal) {
-
-      Loop *L = LI->getLoopFor(POI);
-      Loop *NL = getNearestLoop(POI, L);
-
-      if (NL != L) {
-        // For reducible loops, NL is now an ancestor of Unloop.
-        assert((NL != &Unloop && (!NL || NL->contains(&Unloop))) &&
-               "uninitialized successor");
-        LI->changeLoopFor(POI, NL);
-      } else {
-        // Or the current block is part of a subloop, in which case its parent
-        // is unchanged.
-        assert((FoundIB || Unloop.contains(L)) && "uninitialized successor");
-      }
-    }
-  }
-  // Each irreducible loop within the unloop induces a round of iteration using
-  // the DFS result cached by Traversal.
-  bool Changed = FoundIB;
-  for (unsigned NIters = 0; Changed; ++NIters) {
-    assert(NIters < Unloop.getNumBlocks() && "runaway iterative algorithm");
-
-    // Iterate over the postorder list of blocks, propagating the nearest loop
-    // from successors to predecessors as before.
-    Changed = false;
-    for (LoopBlocksDFS::POIterator POI = DFS.beginPostorder(),
-                                   POE = DFS.endPostorder();
-         POI != POE; ++POI) {
-
-      Loop *L = LI->getLoopFor(*POI);
-      Loop *NL = getNearestLoop(*POI, L);
-      if (NL != L) {
-        assert(NL != &Unloop && (!NL || NL->contains(&Unloop)) &&
-               "uninitialized successor");
-        LI->changeLoopFor(*POI, NL);
-        Changed = true;
-      }
-    }
-  }
-}
-
-/// Remove unloop's blocks from all ancestors below their new parents.
-void UnloopUpdater::removeBlocksFromAncestors() {
-  // Remove all unloop's blocks (including those in nested subloops) from
-  // ancestors below the new parent loop.
-  for (Loop::block_iterator BI = Unloop.block_begin(), BE = Unloop.block_end();
-       BI != BE; ++BI) {
-    Loop *OuterParent = LI->getLoopFor(*BI);
-    if (Unloop.contains(OuterParent)) {
-      while (OuterParent->getParentLoop() != &Unloop)
-        OuterParent = OuterParent->getParentLoop();
-      OuterParent = SubloopParents[OuterParent];
-    }
-    // Remove blocks from former Ancestors except Unloop itself which will be
-    // deleted.
-    for (Loop *OldParent = Unloop.getParentLoop(); OldParent != OuterParent;
-         OldParent = OldParent->getParentLoop()) {
-      assert(OldParent && "new loop is not an ancestor of the original");
-      OldParent->removeBlockFromLoop(*BI);
-    }
-  }
-}
-
-/// Update the parent loop for all subloops directly nested within unloop.
-void UnloopUpdater::updateSubloopParents() {
-  while (!Unloop.empty()) {
-    Loop *Subloop = *std::prev(Unloop.end());
-    Unloop.removeChildLoop(std::prev(Unloop.end()));
-
-    assert(SubloopParents.count(Subloop) && "DFS failed to visit subloop");
-    if (Loop *Parent = SubloopParents[Subloop])
-      Parent->addChildLoop(Subloop);
-    else
-      LI->addTopLevelLoop(Subloop);
-  }
-}
-
-/// Return the nearest parent loop among this block's successors. If a successor
-/// is a subloop header, consider its parent to be the nearest parent of the
-/// subloop's exits.
-///
-/// For subloop blocks, simply update SubloopParents and return NULL.
-Loop *UnloopUpdater::getNearestLoop(BasicBlock *BB, Loop *BBLoop) {
-
-  // Initially for blocks directly contained by Unloop, NearLoop == Unloop and
-  // is considered uninitialized.
-  Loop *NearLoop = BBLoop;
-
-  Loop *Subloop = nullptr;
-  if (NearLoop != &Unloop && Unloop.contains(NearLoop)) {
-    Subloop = NearLoop;
-    // Find the subloop ancestor that is directly contained within Unloop.
-    while (Subloop->getParentLoop() != &Unloop) {
-      Subloop = Subloop->getParentLoop();
-      assert(Subloop && "subloop is not an ancestor of the original loop");
-    }
-    // Get the current nearest parent of the Subloop exits, initially Unloop.
-    NearLoop = SubloopParents.insert({Subloop, &Unloop}).first->second;
-  }
-
-  succ_iterator I = succ_begin(BB), E = succ_end(BB);
-  if (I == E) {
-    assert(!Subloop && "subloop blocks must have a successor");
-    NearLoop = nullptr; // unloop blocks may now exit the function.
-  }
-  for (; I != E; ++I) {
-    if (*I == BB)
-      continue; // self loops are uninteresting
-
-    Loop *L = LI->getLoopFor(*I);
-    if (L == &Unloop) {
-      // This successor has not been processed. This path must lead to an
-      // irreducible backedge.
-      assert((FoundIB || !DFS.hasPostorder(*I)) && "should have seen IB");
-      FoundIB = true;
-    }
-    if (L != &Unloop && Unloop.contains(L)) {
-      // Successor is in a subloop.
-      if (Subloop)
-        continue; // Branching within subloops. Ignore it.
-
-      // BB branches from the original into a subloop header.
-      assert(L->getParentLoop() == &Unloop && "cannot skip into nested loops");
-
-      // Get the current nearest parent of the Subloop's exits.
-      L = SubloopParents[L];
-      // L could be Unloop if the only exit was an irreducible backedge.
-    }
-    if (L == &Unloop) {
-      continue;
-    }
-    // Handle critical edges from Unloop into a sibling loop.
-    if (L && !L->contains(&Unloop)) {
-      L = L->getParentLoop();
-    }
-    // Remember the nearest parent loop among successors or subloop exits.
-    if (NearLoop == &Unloop || !NearLoop || NearLoop->contains(L))
-      NearLoop = L;
-  }
-  if (Subloop) {
-    SubloopParents[Subloop] = NearLoop;
-    return BBLoop;
-  }
-  return NearLoop;
-}
-
-LoopInfo::LoopInfo(const DomTreeBase<BasicBlock> &DomTree) { analyze(DomTree); }
-
-bool LoopInfo::invalidate(Function &F, const PreservedAnalyses &PA,
-                          FunctionAnalysisManager::Invalidator &) {
-  // Check whether the analysis, all analyses on functions, or the function's
-  // CFG have been preserved.
-  auto PAC = PA.getChecker<LoopAnalysis>();
-  return !(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Function>>() ||
-           PAC.preservedSet<CFGAnalyses>());
-}
-
-void LoopInfo::erase(Loop *Unloop) {
-  assert(!Unloop->isInvalid() && "Loop has already been erased!");
-
-  auto InvalidateOnExit = make_scope_exit([&]() { destroy(Unloop); });
-
-  // First handle the special case of no parent loop to simplify the algorithm.
-  if (!Unloop->getParentLoop()) {
-    // Since BBLoop had no parent, Unloop blocks are no longer in a loop.
-    for (Loop::block_iterator I = Unloop->block_begin(),
-                              E = Unloop->block_end();
-         I != E; ++I) {
-
-      // Don't reparent blocks in subloops.
-      if (getLoopFor(*I) != Unloop)
-        continue;
-
-      // Blocks no longer have a parent but are still referenced by Unloop until
-      // the Unloop object is deleted.
-      changeLoopFor(*I, nullptr);
-    }
-
-    // Remove the loop from the top-level LoopInfo object.
-    for (iterator I = begin();; ++I) {
-      assert(I != end() && "Couldn't find loop");
-      if (*I == Unloop) {
-        removeLoop(I);
-        break;
-      }
-    }
-
-    // Move all of the subloops to the top-level.
-    while (!Unloop->empty())
-      addTopLevelLoop(Unloop->removeChildLoop(std::prev(Unloop->end())));
-
-    return;
-  }
-
-  // Update the parent loop for all blocks within the loop. Blocks within
-  // subloops will not change parents.
-  UnloopUpdater Updater(Unloop, this);
-  Updater.updateBlockParents();
-
-  // Remove blocks from former ancestor loops.
-  Updater.removeBlocksFromAncestors();
-
-  // Add direct subloops as children in their new parent loop.
-  Updater.updateSubloopParents();
-
-  // Remove unloop from its parent loop.
-  Loop *ParentLoop = Unloop->getParentLoop();
-  for (Loop::iterator I = ParentLoop->begin();; ++I) {
-    assert(I != ParentLoop->end() && "Couldn't find loop");
-    if (*I == Unloop) {
-      ParentLoop->removeChildLoop(I);
-      break;
-    }
-  }
-}
-
-AnalysisKey LoopAnalysis::Key;
-
-LoopInfo LoopAnalysis::run(Function &F, FunctionAnalysisManager &AM) {
-  // FIXME: Currently we create a LoopInfo from scratch for every function.
-  // This may prove to be too wasteful due to deallocating and re-allocating
-  // memory each time for the underlying map and vector datastructures. At some
-  // point it may prove worthwhile to use a freelist and recycle LoopInfo
-  // objects. I don't want to add that kind of complexity until the scope of
-  // the problem is better understood.
-  LoopInfo LI;
-  LI.analyze(AM.getResult<DominatorTreeAnalysis>(F));
-  return LI;
-}
-
-PreservedAnalyses LoopPrinterPass::run(Function &F,
-                                       FunctionAnalysisManager &AM) {
-  AM.getResult<LoopAnalysis>(F).print(OS);
-  return PreservedAnalyses::all();
-}
-
-void llvm::printLoop(Loop &L, raw_ostream &OS, const std::string &Banner) {
-
-  if (forcePrintModuleIR()) {
-    // handling -print-module-scope
-    OS << Banner << " (loop: ";
-    L.getHeader()->printAsOperand(OS, false);
-    OS << ")\n";
-
-    // printing whole module
-    OS << *L.getHeader()->getModule();
-    return;
-  }
-
-  OS << Banner;
-
-  auto *PreHeader = L.getLoopPreheader();
-  if (PreHeader) {
-    OS << "\n; Preheader:";
-    PreHeader->print(OS);
-    OS << "\n; Loop:";
-  }
-
-  for (auto *Block : L.blocks())
-    if (Block)
-      Block->print(OS);
-    else
-      OS << "Printing <null> block";
-
-  SmallVector<BasicBlock *, 8> ExitBlocks;
-  L.getExitBlocks(ExitBlocks);
-  if (!ExitBlocks.empty()) {
-    OS << "\n; Exit blocks";
-    for (auto *Block : ExitBlocks)
-      if (Block)
-        Block->print(OS);
-      else
-        OS << "Printing <null> block";
-  }
-}
-
-MDNode *llvm::findOptionMDForLoopID(MDNode *LoopID, StringRef Name) {
-  // No loop metadata node, no loop properties.
-  if (!LoopID)
-    return nullptr;
-
-  // First operand should refer to the metadata node itself, for legacy reasons.
-  assert(LoopID->getNumOperands() > 0 && "requires at least one operand");
-  assert(LoopID->getOperand(0) == LoopID && "invalid loop id");
-
-  // Iterate over the metdata node operands and look for MDString metadata.
-  for (unsigned i = 1, e = LoopID->getNumOperands(); i < e; ++i) {
-    MDNode *MD = dyn_cast<MDNode>(LoopID->getOperand(i));
-    if (!MD || MD->getNumOperands() < 1)
-      continue;
-    MDString *S = dyn_cast<MDString>(MD->getOperand(0));
-    if (!S)
-      continue;
-    // Return the operand node if MDString holds expected metadata.
-    if (Name.equals(S->getString()))
-      return MD;
-  }
-
-  // Loop property not found.
-  return nullptr;
-}
-
-MDNode *llvm::findOptionMDForLoop(const Loop *TheLoop, StringRef Name) {
-  return findOptionMDForLoopID(TheLoop->getLoopID(), Name);
-}
-
-bool llvm::isValidAsAccessGroup(MDNode *Node) {
-  return Node->getNumOperands() == 0 && Node->isDistinct();
-}
-
-//===----------------------------------------------------------------------===//
-// LoopInfo implementation
-//
-
-char LoopInfoWrapperPass::ID = 0;
-INITIALIZE_PASS_BEGIN(LoopInfoWrapperPass, "loops", "Natural Loop Information",
-                      true, true)
-INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
-INITIALIZE_PASS_END(LoopInfoWrapperPass, "loops", "Natural Loop Information",
-                    true, true)
-
-bool LoopInfoWrapperPass::runOnFunction(Function &) {
-  releaseMemory();
-  LI.analyze(getAnalysis<DominatorTreeWrapperPass>().getDomTree());
-  return false;
-}
-
-void LoopInfoWrapperPass::verifyAnalysis() const {
-  // LoopInfoWrapperPass is a FunctionPass, but verifying every loop in the
-  // function each time verifyAnalysis is called is very expensive. The
-  // -verify-loop-info option can enable this. In order to perform some
-  // checking by default, LoopPass has been taught to call verifyLoop manually
-  // during loop pass sequences.
-  if (VerifyLoopInfo) {
-    auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
-    LI.verify(DT);
-  }
-}
-
-void LoopInfoWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
-  AU.setPreservesAll();
-  AU.addRequired<DominatorTreeWrapperPass>();
-}
-
-void LoopInfoWrapperPass::print(raw_ostream &OS, const Module *) const {
-  LI.print(OS);
-}
-
-PreservedAnalyses LoopVerifierPass::run(Function &F,
-                                        FunctionAnalysisManager &AM) {
-  LoopInfo &LI = AM.getResult<LoopAnalysis>(F);
-  auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
-  LI.verify(DT);
-  return PreservedAnalyses::all();
-}
-
-//===----------------------------------------------------------------------===//
-// LoopBlocksDFS implementation
-//
-
-/// Traverse the loop blocks and store the DFS result.
-/// Useful for clients that just want the final DFS result and don't need to
-/// visit blocks during the initial traversal.
-void LoopBlocksDFS::perform(LoopInfo *LI) {
-  LoopBlocksTraversal Traversal(*this, LI);
-  for (LoopBlocksTraversal::POTIterator POI = Traversal.begin(),
-                                        POE = Traversal.end();
-       POI != POE; ++POI)
-    ;
-}