1 files changed, 0 insertions, 934 deletions

diff --git a/contrib/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp b/contrib/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
deleted file mode 100644
index 5fa371377c85..000000000000
--- a/contrib/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ /dev/null
@@ -1,934 +0,0 @@
-//===- BasicBlockUtils.cpp - BasicBlock Utilities --------------------------==//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-//
-// This family of functions perform manipulations on basic blocks, and
-// instructions contained within basic blocks.
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/Twine.h"
-#include "llvm/Analysis/CFG.h"
-#include "llvm/Analysis/DomTreeUpdater.h"
-#include "llvm/Analysis/LoopInfo.h"
-#include "llvm/Analysis/MemoryDependenceAnalysis.h"
-#include "llvm/Analysis/MemorySSAUpdater.h"
-#include "llvm/Analysis/PostDominators.h"
-#include "llvm/IR/BasicBlock.h"
-#include "llvm/IR/CFG.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/DebugInfoMetadata.h"
-#include "llvm/IR/Dominators.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/InstrTypes.h"
-#include "llvm/IR/Instruction.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/IntrinsicInst.h"
-#include "llvm/IR/LLVMContext.h"
-#include "llvm/IR/Type.h"
-#include "llvm/IR/User.h"
-#include "llvm/IR/Value.h"
-#include "llvm/IR/ValueHandle.h"
-#include "llvm/Support/Casting.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/Transforms/Utils/Local.h"
-#include <cassert>
-#include <cstdint>
-#include <string>
-#include <utility>
-#include <vector>
-
-using namespace llvm;
-
-#define DEBUG_TYPE "basicblock-utils"
-
-void llvm::DetatchDeadBlocks(
-    ArrayRef<BasicBlock *> BBs,
-    SmallVectorImpl<DominatorTree::UpdateType> *Updates,
-    bool KeepOneInputPHIs) {
-  for (auto *BB : BBs) {
-    // Loop through all of our successors and make sure they know that one
-    // of their predecessors is going away.
-    SmallPtrSet<BasicBlock *, 4> UniqueSuccessors;
-    for (BasicBlock *Succ : successors(BB)) {
-      Succ->removePredecessor(BB, KeepOneInputPHIs);
-      if (Updates && UniqueSuccessors.insert(Succ).second)
-        Updates->push_back({DominatorTree::Delete, BB, Succ});
-    }
-
-    // Zap all the instructions in the block.
-    while (!BB->empty()) {
-      Instruction &I = BB->back();
-      // If this instruction is used, replace uses with an arbitrary value.
-      // Because control flow can't get here, we don't care what we replace the
-      // value with.  Note that since this block is unreachable, and all values
-      // contained within it must dominate their uses, that all uses will
-      // eventually be removed (they are themselves dead).
-      if (!I.use_empty())
-        I.replaceAllUsesWith(UndefValue::get(I.getType()));
-      BB->getInstList().pop_back();
-    }
-    new UnreachableInst(BB->getContext(), BB);
-    assert(BB->getInstList().size() == 1 &&
-           isa<UnreachableInst>(BB->getTerminator()) &&
-           "The successor list of BB isn't empty before "
-           "applying corresponding DTU updates.");
-  }
-}
-
-void llvm::DeleteDeadBlock(BasicBlock *BB, DomTreeUpdater *DTU,
-                           bool KeepOneInputPHIs) {
-  DeleteDeadBlocks({BB}, DTU, KeepOneInputPHIs);
-}
-
-void llvm::DeleteDeadBlocks(ArrayRef <BasicBlock *> BBs, DomTreeUpdater *DTU,
-                            bool KeepOneInputPHIs) {
-#ifndef NDEBUG
-  // Make sure that all predecessors of each dead block is also dead.
-  SmallPtrSet<BasicBlock *, 4> Dead(BBs.begin(), BBs.end());
-  assert(Dead.size() == BBs.size() && "Duplicating blocks?");
-  for (auto *BB : Dead)
-    for (BasicBlock *Pred : predecessors(BB))
-      assert(Dead.count(Pred) && "All predecessors must be dead!");
-#endif
-
-  SmallVector<DominatorTree::UpdateType, 4> Updates;
-  DetatchDeadBlocks(BBs, DTU ? &Updates : nullptr, KeepOneInputPHIs);
-
-  if (DTU)
-    DTU->applyUpdatesPermissive(Updates);
-
-  for (BasicBlock *BB : BBs)
-    if (DTU)
-      DTU->deleteBB(BB);
-    else
-      BB->eraseFromParent();
-}
-
-bool llvm::EliminateUnreachableBlocks(Function &F, DomTreeUpdater *DTU,
-                                      bool KeepOneInputPHIs) {
-  df_iterator_default_set<BasicBlock*> Reachable;
-
-  // Mark all reachable blocks.
-  for (BasicBlock *BB : depth_first_ext(&F, Reachable))
-    (void)BB/* Mark all reachable blocks */;
-
-  // Collect all dead blocks.
-  std::vector<BasicBlock*> DeadBlocks;
-  for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
-    if (!Reachable.count(&*I)) {
-      BasicBlock *BB = &*I;
-      DeadBlocks.push_back(BB);
-    }
-
-  // Delete the dead blocks.
-  DeleteDeadBlocks(DeadBlocks, DTU, KeepOneInputPHIs);
-
-  return !DeadBlocks.empty();
-}
-
-void llvm::FoldSingleEntryPHINodes(BasicBlock *BB,
-                                   MemoryDependenceResults *MemDep) {
-  if (!isa<PHINode>(BB->begin())) return;
-
-  while (PHINode *PN = dyn_cast<PHINode>(BB->begin())) {
-    if (PN->getIncomingValue(0) != PN)
-      PN->replaceAllUsesWith(PN->getIncomingValue(0));
-    else
-      PN->replaceAllUsesWith(UndefValue::get(PN->getType()));
-
-    if (MemDep)
-      MemDep->removeInstruction(PN);  // Memdep updates AA itself.
-
-    PN->eraseFromParent();
-  }
-}
-
-bool llvm::DeleteDeadPHIs(BasicBlock *BB, const TargetLibraryInfo *TLI) {
-  // Recursively deleting a PHI may cause multiple PHIs to be deleted
-  // or RAUW'd undef, so use an array of WeakTrackingVH for the PHIs to delete.
-  SmallVector<WeakTrackingVH, 8> PHIs;
-  for (PHINode &PN : BB->phis())
-    PHIs.push_back(&PN);
-
-  bool Changed = false;
-  for (unsigned i = 0, e = PHIs.size(); i != e; ++i)
-    if (PHINode *PN = dyn_cast_or_null<PHINode>(PHIs[i].operator Value*()))
-      Changed |= RecursivelyDeleteDeadPHINode(PN, TLI);
-
-  return Changed;
-}
-
-bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, DomTreeUpdater *DTU,
-                                     LoopInfo *LI, MemorySSAUpdater *MSSAU,
-                                     MemoryDependenceResults *MemDep) {
-  if (BB->hasAddressTaken())
-    return false;
-
-  // Can't merge if there are multiple predecessors, or no predecessors.
-  BasicBlock *PredBB = BB->getUniquePredecessor();
-  if (!PredBB) return false;
-
-  // Don't break self-loops.
-  if (PredBB == BB) return false;
-  // Don't break unwinding instructions.
-  if (PredBB->getTerminator()->isExceptionalTerminator())
-    return false;
-
-  // Can't merge if there are multiple distinct successors.
-  if (PredBB->getUniqueSuccessor() != BB)
-    return false;
-
-  // Can't merge if there is PHI loop.
-  for (PHINode &PN : BB->phis())
-    for (Value *IncValue : PN.incoming_values())
-      if (IncValue == &PN)
-        return false;
-
-  LLVM_DEBUG(dbgs() << "Merging: " << BB->getName() << " into "
-                    << PredBB->getName() << "\n");
-
-  // Begin by getting rid of unneeded PHIs.
-  SmallVector<AssertingVH<Value>, 4> IncomingValues;
-  if (isa<PHINode>(BB->front())) {
-    for (PHINode &PN : BB->phis())
-      if (!isa<PHINode>(PN.getIncomingValue(0)) ||
-          cast<PHINode>(PN.getIncomingValue(0))->getParent() != BB)
-        IncomingValues.push_back(PN.getIncomingValue(0));
-    FoldSingleEntryPHINodes(BB, MemDep);
-  }
-
-  // DTU update: Collect all the edges that exit BB.
-  // These dominator edges will be redirected from Pred.
-  std::vector<DominatorTree::UpdateType> Updates;
-  if (DTU) {
-    Updates.reserve(1 + (2 * succ_size(BB)));
-    // Add insert edges first. Experimentally, for the particular case of two
-    // blocks that can be merged, with a single successor and single predecessor
-    // respectively, it is beneficial to have all insert updates first. Deleting
-    // edges first may lead to unreachable blocks, followed by inserting edges
-    // making the blocks reachable again. Such DT updates lead to high compile
-    // times. We add inserts before deletes here to reduce compile time.
-    for (auto I = succ_begin(BB), E = succ_end(BB); I != E; ++I)
-      // This successor of BB may already have PredBB as a predecessor.
-      if (llvm::find(successors(PredBB), *I) == succ_end(PredBB))
-        Updates.push_back({DominatorTree::Insert, PredBB, *I});
-    for (auto I = succ_begin(BB), E = succ_end(BB); I != E; ++I)
-      Updates.push_back({DominatorTree::Delete, BB, *I});
-    Updates.push_back({DominatorTree::Delete, PredBB, BB});
-  }
-
-  if (MSSAU)
-    MSSAU->moveAllAfterMergeBlocks(BB, PredBB, &*(BB->begin()));
-
-  // Delete the unconditional branch from the predecessor...
-  PredBB->getInstList().pop_back();
-
-  // Make all PHI nodes that referred to BB now refer to Pred as their
-  // source...
-  BB->replaceAllUsesWith(PredBB);
-
-  // Move all definitions in the successor to the predecessor...
-  PredBB->getInstList().splice(PredBB->end(), BB->getInstList());
-  new UnreachableInst(BB->getContext(), BB);
-
-  // Eliminate duplicate dbg.values describing the entry PHI node post-splice.
-  for (auto Incoming : IncomingValues) {
-    if (isa<Instruction>(*Incoming)) {
-      SmallVector<DbgValueInst *, 2> DbgValues;
-      SmallDenseSet<std::pair<DILocalVariable *, DIExpression *>, 2>
-          DbgValueSet;
-      llvm::findDbgValues(DbgValues, Incoming);
-      for (auto &DVI : DbgValues) {
-        auto R = DbgValueSet.insert({DVI->getVariable(), DVI->getExpression()});
-        if (!R.second)
-          DVI->eraseFromParent();
-      }
-    }
-  }
-
-  // Inherit predecessors name if it exists.
-  if (!PredBB->hasName())
-    PredBB->takeName(BB);
-
-  if (LI)
-    LI->removeBlock(BB);
-
-  if (MemDep)
-    MemDep->invalidateCachedPredecessors();
-
-  // Finally, erase the old block and update dominator info.
-  if (DTU) {
-    assert(BB->getInstList().size() == 1 &&
-           isa<UnreachableInst>(BB->getTerminator()) &&
-           "The successor list of BB isn't empty before "
-           "applying corresponding DTU updates.");
-    DTU->applyUpdatesPermissive(Updates);
-    DTU->deleteBB(BB);
-  }
-
-  else {
-    BB->eraseFromParent(); // Nuke BB if DTU is nullptr.
-  }
-  return true;
-}
-
-void llvm::ReplaceInstWithValue(BasicBlock::InstListType &BIL,
-                                BasicBlock::iterator &BI, Value *V) {
-  Instruction &I = *BI;
-  // Replaces all of the uses of the instruction with uses of the value
-  I.replaceAllUsesWith(V);
-
-  // Make sure to propagate a name if there is one already.
-  if (I.hasName() && !V->hasName())
-    V->takeName(&I);
-
-  // Delete the unnecessary instruction now...
-  BI = BIL.erase(BI);
-}
-
-void llvm::ReplaceInstWithInst(BasicBlock::InstListType &BIL,
-                               BasicBlock::iterator &BI, Instruction *I) {
-  assert(I->getParent() == nullptr &&
-         "ReplaceInstWithInst: Instruction already inserted into basic block!");
-
-  // Copy debug location to newly added instruction, if it wasn't already set
-  // by the caller.
-  if (!I->getDebugLoc())
-    I->setDebugLoc(BI->getDebugLoc());
-
-  // Insert the new instruction into the basic block...
-  BasicBlock::iterator New = BIL.insert(BI, I);
-
-  // Replace all uses of the old instruction, and delete it.
-  ReplaceInstWithValue(BIL, BI, I);
-
-  // Move BI back to point to the newly inserted instruction
-  BI = New;
-}
-
-void llvm::ReplaceInstWithInst(Instruction *From, Instruction *To) {
-  BasicBlock::iterator BI(From);
-  ReplaceInstWithInst(From->getParent()->getInstList(), BI, To);
-}
-
-BasicBlock *llvm::SplitEdge(BasicBlock *BB, BasicBlock *Succ, DominatorTree *DT,
-                            LoopInfo *LI, MemorySSAUpdater *MSSAU) {
-  unsigned SuccNum = GetSuccessorNumber(BB, Succ);
-
-  // If this is a critical edge, let SplitCriticalEdge do it.
-  Instruction *LatchTerm = BB->getTerminator();
-  if (SplitCriticalEdge(
-          LatchTerm, SuccNum,
-          CriticalEdgeSplittingOptions(DT, LI, MSSAU).setPreserveLCSSA()))
-    return LatchTerm->getSuccessor(SuccNum);
-
-  // If the edge isn't critical, then BB has a single successor or Succ has a
-  // single pred.  Split the block.
-  if (BasicBlock *SP = Succ->getSinglePredecessor()) {
-    // If the successor only has a single pred, split the top of the successor
-    // block.
-    assert(SP == BB && "CFG broken");
-    SP = nullptr;
-    return SplitBlock(Succ, &Succ->front(), DT, LI, MSSAU);
-  }
-
-  // Otherwise, if BB has a single successor, split it at the bottom of the
-  // block.
-  assert(BB->getTerminator()->getNumSuccessors() == 1 &&
-         "Should have a single succ!");
-  return SplitBlock(BB, BB->getTerminator(), DT, LI, MSSAU);
-}
-
-unsigned
-llvm::SplitAllCriticalEdges(Function &F,
-                            const CriticalEdgeSplittingOptions &Options) {
-  unsigned NumBroken = 0;
-  for (BasicBlock &BB : F) {
-    Instruction *TI = BB.getTerminator();
-    if (TI->getNumSuccessors() > 1 && !isa<IndirectBrInst>(TI))
-      for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
-        if (SplitCriticalEdge(TI, i, Options))
-          ++NumBroken;
-  }
-  return NumBroken;
-}
-
-BasicBlock *llvm::SplitBlock(BasicBlock *Old, Instruction *SplitPt,
-                             DominatorTree *DT, LoopInfo *LI,
-                             MemorySSAUpdater *MSSAU) {
-  BasicBlock::iterator SplitIt = SplitPt->getIterator();
-  while (isa<PHINode>(SplitIt) || SplitIt->isEHPad())
-    ++SplitIt;
-  BasicBlock *New = Old->splitBasicBlock(SplitIt, Old->getName()+".split");
-
-  // The new block lives in whichever loop the old one did. This preserves
-  // LCSSA as well, because we force the split point to be after any PHI nodes.
-  if (LI)
-    if (Loop *L = LI->getLoopFor(Old))
-      L->addBasicBlockToLoop(New, *LI);
-
-  if (DT)
-    // Old dominates New. New node dominates all other nodes dominated by Old.
-    if (DomTreeNode *OldNode = DT->getNode(Old)) {
-      std::vector<DomTreeNode *> Children(OldNode->begin(), OldNode->end());
-
-      DomTreeNode *NewNode = DT->addNewBlock(New, Old);
-      for (DomTreeNode *I : Children)
-        DT->changeImmediateDominator(I, NewNode);
-    }
-
-  // Move MemoryAccesses still tracked in Old, but part of New now.
-  // Update accesses in successor blocks accordingly.
-  if (MSSAU)
-    MSSAU->moveAllAfterSpliceBlocks(Old, New, &*(New->begin()));
-
-  return New;
-}
-
-/// Update DominatorTree, LoopInfo, and LCCSA analysis information.
-static void UpdateAnalysisInformation(BasicBlock *OldBB, BasicBlock *NewBB,
-                                      ArrayRef<BasicBlock *> Preds,
-                                      DominatorTree *DT, LoopInfo *LI,
-                                      MemorySSAUpdater *MSSAU,
-                                      bool PreserveLCSSA, bool &HasLoopExit) {
-  // Update dominator tree if available.
-  if (DT) {
-    if (OldBB == DT->getRootNode()->getBlock()) {
-      assert(NewBB == &NewBB->getParent()->getEntryBlock());
-      DT->setNewRoot(NewBB);
-    } else {
-      // Split block expects NewBB to have a non-empty set of predecessors.
-      DT->splitBlock(NewBB);
-    }
-  }
-
-  // Update MemoryPhis after split if MemorySSA is available
-  if (MSSAU)
-    MSSAU->wireOldPredecessorsToNewImmediatePredecessor(OldBB, NewBB, Preds);
-
-  // The rest of the logic is only relevant for updating the loop structures.
-  if (!LI)
-    return;
-
-  assert(DT && "DT should be available to update LoopInfo!");
-  Loop *L = LI->getLoopFor(OldBB);
-
-  // If we need to preserve loop analyses, collect some information about how
-  // this split will affect loops.
-  bool IsLoopEntry = !!L;
-  bool SplitMakesNewLoopHeader = false;
-  for (BasicBlock *Pred : Preds) {
-    // Preds that are not reachable from entry should not be used to identify if
-    // OldBB is a loop entry or if SplitMakesNewLoopHeader. Unreachable blocks
-    // are not within any loops, so we incorrectly mark SplitMakesNewLoopHeader
-    // as true and make the NewBB the header of some loop. This breaks LI.
-    if (!DT->isReachableFromEntry(Pred))
-      continue;
-    // If we need to preserve LCSSA, determine if any of the preds is a loop
-    // exit.
-    if (PreserveLCSSA)
-      if (Loop *PL = LI->getLoopFor(Pred))
-        if (!PL->contains(OldBB))
-          HasLoopExit = true;
-
-    // If we need to preserve LoopInfo, note whether any of the preds crosses
-    // an interesting loop boundary.
-    if (!L)
-      continue;
-    if (L->contains(Pred))
-      IsLoopEntry = false;
-    else
-      SplitMakesNewLoopHeader = true;
-  }
-
-  // Unless we have a loop for OldBB, nothing else to do here.
-  if (!L)
-    return;
-
-  if (IsLoopEntry) {
-    // Add the new block to the nearest enclosing loop (and not an adjacent
-    // loop). To find this, examine each of the predecessors and determine which
-    // loops enclose them, and select the most-nested loop which contains the
-    // loop containing the block being split.
-    Loop *InnermostPredLoop = nullptr;
-    for (BasicBlock *Pred : Preds) {
-      if (Loop *PredLoop = LI->getLoopFor(Pred)) {
-        // Seek a loop which actually contains the block being split (to avoid
-        // adjacent loops).
-        while (PredLoop && !PredLoop->contains(OldBB))
-          PredLoop = PredLoop->getParentLoop();
-
-        // Select the most-nested of these loops which contains the block.
-        if (PredLoop && PredLoop->contains(OldBB) &&
-            (!InnermostPredLoop ||
-             InnermostPredLoop->getLoopDepth() < PredLoop->getLoopDepth()))
-          InnermostPredLoop = PredLoop;
-      }
-    }
-
-    if (InnermostPredLoop)
-      InnermostPredLoop->addBasicBlockToLoop(NewBB, *LI);
-  } else {
-    L->addBasicBlockToLoop(NewBB, *LI);
-    if (SplitMakesNewLoopHeader)
-      L->moveToHeader(NewBB);
-  }
-}
-
-/// Update the PHI nodes in OrigBB to include the values coming from NewBB.
-/// This also updates AliasAnalysis, if available.
-static void UpdatePHINodes(BasicBlock *OrigBB, BasicBlock *NewBB,
-                           ArrayRef<BasicBlock *> Preds, BranchInst *BI,
-                           bool HasLoopExit) {
-  // Otherwise, create a new PHI node in NewBB for each PHI node in OrigBB.
-  SmallPtrSet<BasicBlock *, 16> PredSet(Preds.begin(), Preds.end());
-  for (BasicBlock::iterator I = OrigBB->begin(); isa<PHINode>(I); ) {
-    PHINode *PN = cast<PHINode>(I++);
-
-    // Check to see if all of the values coming in are the same.  If so, we
-    // don't need to create a new PHI node, unless it's needed for LCSSA.
-    Value *InVal = nullptr;
-    if (!HasLoopExit) {
-      InVal = PN->getIncomingValueForBlock(Preds[0]);
-      for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
-        if (!PredSet.count(PN->getIncomingBlock(i)))
-          continue;
-        if (!InVal)
-          InVal = PN->getIncomingValue(i);
-        else if (InVal != PN->getIncomingValue(i)) {
-          InVal = nullptr;
-          break;
-        }
-      }
-    }
-
-    if (InVal) {
-      // If all incoming values for the new PHI would be the same, just don't
-      // make a new PHI.  Instead, just remove the incoming values from the old
-      // PHI.
-
-      // NOTE! This loop walks backwards for a reason! First off, this minimizes
-      // the cost of removal if we end up removing a large number of values, and
-      // second off, this ensures that the indices for the incoming values
-      // aren't invalidated when we remove one.
-      for (int64_t i = PN->getNumIncomingValues() - 1; i >= 0; --i)
-        if (PredSet.count(PN->getIncomingBlock(i)))
-          PN->removeIncomingValue(i, false);
-
-      // Add an incoming value to the PHI node in the loop for the preheader
-      // edge.
-      PN->addIncoming(InVal, NewBB);
-      continue;
-    }
-
-    // If the values coming into the block are not the same, we need a new
-    // PHI.
-    // Create the new PHI node, insert it into NewBB at the end of the block
-    PHINode *NewPHI =
-        PHINode::Create(PN->getType(), Preds.size(), PN->getName() + ".ph", BI);
-
-    // NOTE! This loop walks backwards for a reason! First off, this minimizes
-    // the cost of removal if we end up removing a large number of values, and
-    // second off, this ensures that the indices for the incoming values aren't
-    // invalidated when we remove one.
-    for (int64_t i = PN->getNumIncomingValues() - 1; i >= 0; --i) {
-      BasicBlock *IncomingBB = PN->getIncomingBlock(i);
-      if (PredSet.count(IncomingBB)) {
-        Value *V = PN->removeIncomingValue(i, false);
-        NewPHI->addIncoming(V, IncomingBB);
-      }
-    }
-
-    PN->addIncoming(NewPHI, NewBB);
-  }
-}
-
-BasicBlock *llvm::SplitBlockPredecessors(BasicBlock *BB,
-                                         ArrayRef<BasicBlock *> Preds,
-                                         const char *Suffix, DominatorTree *DT,
-                                         LoopInfo *LI, MemorySSAUpdater *MSSAU,
-                                         bool PreserveLCSSA) {
-  // Do not attempt to split that which cannot be split.
-  if (!BB->canSplitPredecessors())
-    return nullptr;
-
-  // For the landingpads we need to act a bit differently.
-  // Delegate this work to the SplitLandingPadPredecessors.
-  if (BB->isLandingPad()) {
-    SmallVector<BasicBlock*, 2> NewBBs;
-    std::string NewName = std::string(Suffix) + ".split-lp";
-
-    SplitLandingPadPredecessors(BB, Preds, Suffix, NewName.c_str(), NewBBs, DT,
-                                LI, MSSAU, PreserveLCSSA);
-    return NewBBs[0];
-  }
-
-  // Create new basic block, insert right before the original block.
-  BasicBlock *NewBB = BasicBlock::Create(
-      BB->getContext(), BB->getName() + Suffix, BB->getParent(), BB);
-
-  // The new block unconditionally branches to the old block.
-  BranchInst *BI = BranchInst::Create(BB, NewBB);
-  // Splitting the predecessors of a loop header creates a preheader block.
-  if (LI && LI->isLoopHeader(BB))
-    // Using the loop start line number prevents debuggers stepping into the
-    // loop body for this instruction.
-    BI->setDebugLoc(LI->getLoopFor(BB)->getStartLoc());
-  else
-    BI->setDebugLoc(BB->getFirstNonPHIOrDbg()->getDebugLoc());
-
-  // Move the edges from Preds to point to NewBB instead of BB.
-  for (unsigned i = 0, e = Preds.size(); i != e; ++i) {
-    // This is slightly more strict than necessary; the minimum requirement
-    // is that there be no more than one indirectbr branching to BB. And
-    // all BlockAddress uses would need to be updated.
-    assert(!isa<IndirectBrInst>(Preds[i]->getTerminator()) &&
-           "Cannot split an edge from an IndirectBrInst");
-    assert(!isa<CallBrInst>(Preds[i]->getTerminator()) &&
-           "Cannot split an edge from a CallBrInst");
-    Preds[i]->getTerminator()->replaceUsesOfWith(BB, NewBB);
-  }
-
-  // Insert a new PHI node into NewBB for every PHI node in BB and that new PHI
-  // node becomes an incoming value for BB's phi node.  However, if the Preds
-  // list is empty, we need to insert dummy entries into the PHI nodes in BB to
-  // account for the newly created predecessor.
-  if (Preds.empty()) {
-    // Insert dummy values as the incoming value.
-    for (BasicBlock::iterator I = BB->begin(); isa<PHINode>(I); ++I)
-      cast<PHINode>(I)->addIncoming(UndefValue::get(I->getType()), NewBB);
-  }
-
-  // Update DominatorTree, LoopInfo, and LCCSA analysis information.
-  bool HasLoopExit = false;
-  UpdateAnalysisInformation(BB, NewBB, Preds, DT, LI, MSSAU, PreserveLCSSA,
-                            HasLoopExit);
-
-  if (!Preds.empty()) {
-    // Update the PHI nodes in BB with the values coming from NewBB.
-    UpdatePHINodes(BB, NewBB, Preds, BI, HasLoopExit);
-  }
-
-  return NewBB;
-}
-
-void llvm::SplitLandingPadPredecessors(BasicBlock *OrigBB,
-                                       ArrayRef<BasicBlock *> Preds,
-                                       const char *Suffix1, const char *Suffix2,
-                                       SmallVectorImpl<BasicBlock *> &NewBBs,
-                                       DominatorTree *DT, LoopInfo *LI,
-                                       MemorySSAUpdater *MSSAU,
-                                       bool PreserveLCSSA) {
-  assert(OrigBB->isLandingPad() && "Trying to split a non-landing pad!");
-
-  // Create a new basic block for OrigBB's predecessors listed in Preds. Insert
-  // it right before the original block.
-  BasicBlock *NewBB1 = BasicBlock::Create(OrigBB->getContext(),
-                                          OrigBB->getName() + Suffix1,
-                                          OrigBB->getParent(), OrigBB);
-  NewBBs.push_back(NewBB1);
-
-  // The new block unconditionally branches to the old block.
-  BranchInst *BI1 = BranchInst::Create(OrigBB, NewBB1);
-  BI1->setDebugLoc(OrigBB->getFirstNonPHI()->getDebugLoc());
-
-  // Move the edges from Preds to point to NewBB1 instead of OrigBB.
-  for (unsigned i = 0, e = Preds.size(); i != e; ++i) {
-    // This is slightly more strict than necessary; the minimum requirement
-    // is that there be no more than one indirectbr branching to BB. And
-    // all BlockAddress uses would need to be updated.
-    assert(!isa<IndirectBrInst>(Preds[i]->getTerminator()) &&
-           "Cannot split an edge from an IndirectBrInst");
-    Preds[i]->getTerminator()->replaceUsesOfWith(OrigBB, NewBB1);
-  }
-
-  bool HasLoopExit = false;
-  UpdateAnalysisInformation(OrigBB, NewBB1, Preds, DT, LI, MSSAU, PreserveLCSSA,
-                            HasLoopExit);
-
-  // Update the PHI nodes in OrigBB with the values coming from NewBB1.
-  UpdatePHINodes(OrigBB, NewBB1, Preds, BI1, HasLoopExit);
-
-  // Move the remaining edges from OrigBB to point to NewBB2.
-  SmallVector<BasicBlock*, 8> NewBB2Preds;
-  for (pred_iterator i = pred_begin(OrigBB), e = pred_end(OrigBB);
-       i != e; ) {
-    BasicBlock *Pred = *i++;
-    if (Pred == NewBB1) continue;
-    assert(!isa<IndirectBrInst>(Pred->getTerminator()) &&
-           "Cannot split an edge from an IndirectBrInst");
-    NewBB2Preds.push_back(Pred);
-    e = pred_end(OrigBB);
-  }
-
-  BasicBlock *NewBB2 = nullptr;
-  if (!NewBB2Preds.empty()) {
-    // Create another basic block for the rest of OrigBB's predecessors.
-    NewBB2 = BasicBlock::Create(OrigBB->getContext(),
-                                OrigBB->getName() + Suffix2,
-                                OrigBB->getParent(), OrigBB);
-    NewBBs.push_back(NewBB2);
-
-    // The new block unconditionally branches to the old block.
-    BranchInst *BI2 = BranchInst::Create(OrigBB, NewBB2);
-    BI2->setDebugLoc(OrigBB->getFirstNonPHI()->getDebugLoc());
-
-    // Move the remaining edges from OrigBB to point to NewBB2.
-    for (BasicBlock *NewBB2Pred : NewBB2Preds)
-      NewBB2Pred->getTerminator()->replaceUsesOfWith(OrigBB, NewBB2);
-
-    // Update DominatorTree, LoopInfo, and LCCSA analysis information.
-    HasLoopExit = false;
-    UpdateAnalysisInformation(OrigBB, NewBB2, NewBB2Preds, DT, LI, MSSAU,
-                              PreserveLCSSA, HasLoopExit);
-
-    // Update the PHI nodes in OrigBB with the values coming from NewBB2.
-    UpdatePHINodes(OrigBB, NewBB2, NewBB2Preds, BI2, HasLoopExit);
-  }
-
-  LandingPadInst *LPad = OrigBB->getLandingPadInst();
-  Instruction *Clone1 = LPad->clone();
-  Clone1->setName(Twine("lpad") + Suffix1);
-  NewBB1->getInstList().insert(NewBB1->getFirstInsertionPt(), Clone1);
-
-  if (NewBB2) {
-    Instruction *Clone2 = LPad->clone();
-    Clone2->setName(Twine("lpad") + Suffix2);
-    NewBB2->getInstList().insert(NewBB2->getFirstInsertionPt(), Clone2);
-
-    // Create a PHI node for the two cloned landingpad instructions only
-    // if the original landingpad instruction has some uses.
-    if (!LPad->use_empty()) {
-      assert(!LPad->getType()->isTokenTy() &&
-             "Split cannot be applied if LPad is token type. Otherwise an "
-             "invalid PHINode of token type would be created.");
-      PHINode *PN = PHINode::Create(LPad->getType(), 2, "lpad.phi", LPad);
-      PN->addIncoming(Clone1, NewBB1);
-      PN->addIncoming(Clone2, NewBB2);
-      LPad->replaceAllUsesWith(PN);
-    }
-    LPad->eraseFromParent();
-  } else {
-    // There is no second clone. Just replace the landing pad with the first
-    // clone.
-    LPad->replaceAllUsesWith(Clone1);
-    LPad->eraseFromParent();
-  }
-}
-
-ReturnInst *llvm::FoldReturnIntoUncondBranch(ReturnInst *RI, BasicBlock *BB,
-                                             BasicBlock *Pred,
-                                             DomTreeUpdater *DTU) {
-  Instruction *UncondBranch = Pred->getTerminator();
-  // Clone the return and add it to the end of the predecessor.
-  Instruction *NewRet = RI->clone();
-  Pred->getInstList().push_back(NewRet);
-
-  // If the return instruction returns a value, and if the value was a
-  // PHI node in "BB", propagate the right value into the return.
-  for (User::op_iterator i = NewRet->op_begin(), e = NewRet->op_end();
-       i != e; ++i) {
-    Value *V = *i;
-    Instruction *NewBC = nullptr;
-    if (BitCastInst *BCI = dyn_cast<BitCastInst>(V)) {
-      // Return value might be bitcasted. Clone and insert it before the
-      // return instruction.
-      V = BCI->getOperand(0);
-      NewBC = BCI->clone();
-      Pred->getInstList().insert(NewRet->getIterator(), NewBC);
-      *i = NewBC;
-    }
-    if (PHINode *PN = dyn_cast<PHINode>(V)) {
-      if (PN->getParent() == BB) {
-        if (NewBC)
-          NewBC->setOperand(0, PN->getIncomingValueForBlock(Pred));
-        else
-          *i = PN->getIncomingValueForBlock(Pred);
-      }
-    }
-  }
-
-  // Update any PHI nodes in the returning block to realize that we no
-  // longer branch to them.
-  BB->removePredecessor(Pred);
-  UncondBranch->eraseFromParent();
-
-  if (DTU)
-    DTU->applyUpdates({{DominatorTree::Delete, Pred, BB}});
-
-  return cast<ReturnInst>(NewRet);
-}
-
-Instruction *llvm::SplitBlockAndInsertIfThen(Value *Cond,
-                                             Instruction *SplitBefore,
-                                             bool Unreachable,
-                                             MDNode *BranchWeights,
-                                             DominatorTree *DT, LoopInfo *LI,
-                                             BasicBlock *ThenBlock) {
-  BasicBlock *Head = SplitBefore->getParent();
-  BasicBlock *Tail = Head->splitBasicBlock(SplitBefore->getIterator());
-  Instruction *HeadOldTerm = Head->getTerminator();
-  LLVMContext &C = Head->getContext();
-  Instruction *CheckTerm;
-  bool CreateThenBlock = (ThenBlock == nullptr);
-  if (CreateThenBlock) {
-    ThenBlock = BasicBlock::Create(C, "", Head->getParent(), Tail);
-    if (Unreachable)
-      CheckTerm = new UnreachableInst(C, ThenBlock);
-    else
-      CheckTerm = BranchInst::Create(Tail, ThenBlock);
-    CheckTerm->setDebugLoc(SplitBefore->getDebugLoc());
-  } else
-    CheckTerm = ThenBlock->getTerminator();
-  BranchInst *HeadNewTerm =
-    BranchInst::Create(/*ifTrue*/ThenBlock, /*ifFalse*/Tail, Cond);
-  HeadNewTerm->setMetadata(LLVMContext::MD_prof, BranchWeights);
-  ReplaceInstWithInst(HeadOldTerm, HeadNewTerm);
-
-  if (DT) {
-    if (DomTreeNode *OldNode = DT->getNode(Head)) {
-      std::vector<DomTreeNode *> Children(OldNode->begin(), OldNode->end());
-
-      DomTreeNode *NewNode = DT->addNewBlock(Tail, Head);
-      for (DomTreeNode *Child : Children)
-        DT->changeImmediateDominator(Child, NewNode);
-
-      // Head dominates ThenBlock.
-      if (CreateThenBlock)
-        DT->addNewBlock(ThenBlock, Head);
-      else
-        DT->changeImmediateDominator(ThenBlock, Head);
-    }
-  }
-
-  if (LI) {
-    if (Loop *L = LI->getLoopFor(Head)) {
-      L->addBasicBlockToLoop(ThenBlock, *LI);
-      L->addBasicBlockToLoop(Tail, *LI);
-    }
-  }
-
-  return CheckTerm;
-}
-
-void llvm::SplitBlockAndInsertIfThenElse(Value *Cond, Instruction *SplitBefore,
-                                         Instruction **ThenTerm,
-                                         Instruction **ElseTerm,
-                                         MDNode *BranchWeights) {
-  BasicBlock *Head = SplitBefore->getParent();
-  BasicBlock *Tail = Head->splitBasicBlock(SplitBefore->getIterator());
-  Instruction *HeadOldTerm = Head->getTerminator();
-  LLVMContext &C = Head->getContext();
-  BasicBlock *ThenBlock = BasicBlock::Create(C, "", Head->getParent(), Tail);
-  BasicBlock *ElseBlock = BasicBlock::Create(C, "", Head->getParent(), Tail);
-  *ThenTerm = BranchInst::Create(Tail, ThenBlock);
-  (*ThenTerm)->setDebugLoc(SplitBefore->getDebugLoc());
-  *ElseTerm = BranchInst::Create(Tail, ElseBlock);
-  (*ElseTerm)->setDebugLoc(SplitBefore->getDebugLoc());
-  BranchInst *HeadNewTerm =
-    BranchInst::Create(/*ifTrue*/ThenBlock, /*ifFalse*/ElseBlock, Cond);
-  HeadNewTerm->setMetadata(LLVMContext::MD_prof, BranchWeights);
-  ReplaceInstWithInst(HeadOldTerm, HeadNewTerm);
-}
-
-Value *llvm::GetIfCondition(BasicBlock *BB, BasicBlock *&IfTrue,
-                             BasicBlock *&IfFalse) {
-  PHINode *SomePHI = dyn_cast<PHINode>(BB->begin());
-  BasicBlock *Pred1 = nullptr;
-  BasicBlock *Pred2 = nullptr;
-
-  if (SomePHI) {
-    if (SomePHI->getNumIncomingValues() != 2)
-      return nullptr;
-    Pred1 = SomePHI->getIncomingBlock(0);
-    Pred2 = SomePHI->getIncomingBlock(1);
-  } else {
-    pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
-    if (PI == PE) // No predecessor
-      return nullptr;
-    Pred1 = *PI++;
-    if (PI == PE) // Only one predecessor
-      return nullptr;
-    Pred2 = *PI++;
-    if (PI != PE) // More than two predecessors
-      return nullptr;
-  }
-
-  // We can only handle branches.  Other control flow will be lowered to
-  // branches if possible anyway.
-  BranchInst *Pred1Br = dyn_cast<BranchInst>(Pred1->getTerminator());
-  BranchInst *Pred2Br = dyn_cast<BranchInst>(Pred2->getTerminator());
-  if (!Pred1Br || !Pred2Br)
-    return nullptr;
-
-  // Eliminate code duplication by ensuring that Pred1Br is conditional if
-  // either are.
-  if (Pred2Br->isConditional()) {
-    // If both branches are conditional, we don't have an "if statement".  In
-    // reality, we could transform this case, but since the condition will be
-    // required anyway, we stand no chance of eliminating it, so the xform is
-    // probably not profitable.
-    if (Pred1Br->isConditional())
-      return nullptr;
-
-    std::swap(Pred1, Pred2);
-    std::swap(Pred1Br, Pred2Br);
-  }
-
-  if (Pred1Br->isConditional()) {
-    // The only thing we have to watch out for here is to make sure that Pred2
-    // doesn't have incoming edges from other blocks.  If it does, the condition
-    // doesn't dominate BB.
-    if (!Pred2->getSinglePredecessor())
-      return nullptr;
-
-    // If we found a conditional branch predecessor, make sure that it branches
-    // to BB and Pred2Br.  If it doesn't, this isn't an "if statement".
-    if (Pred1Br->getSuccessor(0) == BB &&
-        Pred1Br->getSuccessor(1) == Pred2) {
-      IfTrue = Pred1;
-      IfFalse = Pred2;
-    } else if (Pred1Br->getSuccessor(0) == Pred2 &&
-               Pred1Br->getSuccessor(1) == BB) {
-      IfTrue = Pred2;
-      IfFalse = Pred1;
-    } else {
-      // We know that one arm of the conditional goes to BB, so the other must
-      // go somewhere unrelated, and this must not be an "if statement".
-      return nullptr;
-    }
-
-    return Pred1Br->getCondition();
-  }
-
-  // Ok, if we got here, both predecessors end with an unconditional branch to
-  // BB.  Don't panic!  If both blocks only have a single (identical)
-  // predecessor, and THAT is a conditional branch, then we're all ok!
-  BasicBlock *CommonPred = Pred1->getSinglePredecessor();
-  if (CommonPred == nullptr || CommonPred != Pred2->getSinglePredecessor())
-    return nullptr;
-
-  // Otherwise, if this is a conditional branch, then we can use it!
-  BranchInst *BI = dyn_cast<BranchInst>(CommonPred->getTerminator());
-  if (!BI) return nullptr;
-
-  assert(BI->isConditional() && "Two successors but not conditional?");
-  if (BI->getSuccessor(0) == Pred1) {
-    IfTrue = Pred1;
-    IfFalse = Pred2;
-  } else {
-    IfTrue = Pred2;
-    IfFalse = Pred1;
-  }
-  return BI->getCondition();
-}