[llvm] r204389 - [Constant Hoisting] Extend coverage of the constant hoisting pass.

Eric Christopher echristo at gmail.com
Thu Mar 20 13:29:32 PDT 2014


For the record, feel free to post-commit review it per normal, it
wasn't that kind of request. Just "hey, can you make it easier to do
post-commit review on" :)

-eric

On Thu, Mar 20, 2014 at 1:24 PM, Eric Christopher <echristo at gmail.com> wrote:
> Really appreciate it. Thanks Juergen! :)
>
> -eric
>
> On Thu, Mar 20, 2014 at 1:21 PM, Juergen Ributzka <juergen at apple.com> wrote:
>> Ok, I will try to break it up into sensible pieces.
>>
>> -Juergen
>>
>> On Mar 20, 2014, at 1:13 PM, Eric Christopher <echristo at gmail.com> wrote:
>>
>>> Actually, this patch is almost impossible to review otherwise. Would
>>> you mind doing this? :)
>>>
>>> -eric
>>>
>>> On Thu, Mar 20, 2014 at 1:12 PM, Eric Christopher <echristo at gmail.com> wrote:
>>>> Is there some reason this couldn't be split out into refactoring and
>>>> then adding new functionality?
>>>>
>>>> -eric
>>>>
>>>> On Thu, Mar 20, 2014 at 12:55 PM, Juergen Ributzka <juergen at apple.com> wrote:
>>>>> Author: ributzka
>>>>> Date: Thu Mar 20 14:55:52 2014
>>>>> New Revision: 204389
>>>>>
>>>>> URL: http://llvm.org/viewvc/llvm-project?rev=204389&view=rev
>>>>> Log:
>>>>> [Constant Hoisting] Extend coverage of the constant hoisting pass.
>>>>>
>>>>> This commit extends the coverage of the constant hoisting pass, adds additonal
>>>>> debug output and updates the function names according to the style guide.
>>>>>
>>>>> Related to <rdar://problem/16381500>
>>>>>
>>>>> Modified:
>>>>>    llvm/trunk/include/llvm/Analysis/TargetTransformInfo.h
>>>>>    llvm/trunk/lib/Analysis/TargetTransformInfo.cpp
>>>>>    llvm/trunk/lib/Target/X86/X86TargetTransformInfo.cpp
>>>>>    llvm/trunk/lib/Transforms/Scalar/ConstantHoisting.cpp
>>>>>    llvm/trunk/test/CodeGen/X86/lsr-interesting-step.ll
>>>>>    llvm/trunk/test/CodeGen/X86/negate-add-zero.ll
>>>>>    llvm/trunk/test/Transforms/ConstantHoisting/X86/phi.ll
>>>>>
>>>>> Modified: llvm/trunk/include/llvm/Analysis/TargetTransformInfo.h
>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/TargetTransformInfo.h?rev=204389&r1=204388&r2=204389&view=diff
>>>>> ==============================================================================
>>>>> --- llvm/trunk/include/llvm/Analysis/TargetTransformInfo.h (original)
>>>>> +++ llvm/trunk/include/llvm/Analysis/TargetTransformInfo.h Thu Mar 20 14:55:52 2014
>>>>> @@ -297,10 +297,10 @@ public:
>>>>>   /// \brief Return the expected cost of materialization for the given integer
>>>>>   /// immediate of the specified type for a given instruction. The cost can be
>>>>>   /// zero if the immediate can be folded into the specified instruction.
>>>>> -  virtual unsigned getIntImmCost(unsigned Opcode, const APInt &Imm,
>>>>> -                                 Type *Ty) const;
>>>>> -  virtual unsigned getIntImmCost(Intrinsic::ID IID, const APInt &Imm,
>>>>> +  virtual unsigned getIntImmCost(unsigned Opc, unsigned Idx, const APInt &Imm,
>>>>>                                  Type *Ty) const;
>>>>> +  virtual unsigned getIntImmCost(Intrinsic::ID IID, unsigned Idx,
>>>>> +                                 const APInt &Imm, Type *Ty) const;
>>>>>   /// @}
>>>>>
>>>>>   /// \name Vector Target Information
>>>>>
>>>>> Modified: llvm/trunk/lib/Analysis/TargetTransformInfo.cpp
>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/TargetTransformInfo.cpp?rev=204389&r1=204388&r2=204389&view=diff
>>>>> ==============================================================================
>>>>> --- llvm/trunk/lib/Analysis/TargetTransformInfo.cpp (original)
>>>>> +++ llvm/trunk/lib/Analysis/TargetTransformInfo.cpp Thu Mar 20 14:55:52 2014
>>>>> @@ -148,14 +148,14 @@ unsigned TargetTransformInfo::getIntImmC
>>>>>   return PrevTTI->getIntImmCost(Imm, Ty);
>>>>> }
>>>>>
>>>>> -unsigned TargetTransformInfo::getIntImmCost(unsigned Opcode, const APInt &Imm,
>>>>> -                                            Type *Ty) const {
>>>>> -  return PrevTTI->getIntImmCost(Opcode, Imm, Ty);
>>>>> +unsigned TargetTransformInfo::getIntImmCost(unsigned Opc, unsigned Idx,
>>>>> +                                            const APInt &Imm, Type *Ty) const {
>>>>> +  return PrevTTI->getIntImmCost(Opc, Idx, Imm, Ty);
>>>>> }
>>>>>
>>>>> -unsigned TargetTransformInfo::getIntImmCost(Intrinsic::ID IID, const APInt &Imm,
>>>>> -                                            Type *Ty) const {
>>>>> -  return PrevTTI->getIntImmCost(IID, Imm, Ty);
>>>>> +unsigned TargetTransformInfo::getIntImmCost(Intrinsic::ID IID, unsigned Idx,
>>>>> +                                            const APInt &Imm, Type *Ty) const {
>>>>> +  return PrevTTI->getIntImmCost(IID, Idx, Imm, Ty);
>>>>> }
>>>>>
>>>>> unsigned TargetTransformInfo::getNumberOfRegisters(bool Vector) const {
>>>>> @@ -539,12 +539,12 @@ struct NoTTI final : ImmutablePass, Targ
>>>>>     return TCC_Basic;
>>>>>   }
>>>>>
>>>>> -  unsigned getIntImmCost(unsigned Opcode, const APInt &Imm,
>>>>> +  unsigned getIntImmCost(unsigned Opcode, unsigned Idx, const APInt &Imm,
>>>>>                          Type *Ty) const override {
>>>>>     return TCC_Free;
>>>>>   }
>>>>>
>>>>> -  unsigned getIntImmCost(Intrinsic::ID IID, const APInt &Imm,
>>>>> +  unsigned getIntImmCost(Intrinsic::ID IID, unsigned Idx, const APInt &Imm,
>>>>>                          Type *Ty) const override {
>>>>>     return TCC_Free;
>>>>>   }
>>>>>
>>>>> Modified: llvm/trunk/lib/Target/X86/X86TargetTransformInfo.cpp
>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86TargetTransformInfo.cpp?rev=204389&r1=204388&r2=204389&view=diff
>>>>> ==============================================================================
>>>>> --- llvm/trunk/lib/Target/X86/X86TargetTransformInfo.cpp (original)
>>>>> +++ llvm/trunk/lib/Target/X86/X86TargetTransformInfo.cpp Thu Mar 20 14:55:52 2014
>>>>> @@ -103,9 +103,9 @@ public:
>>>>>
>>>>>   unsigned getIntImmCost(const APInt &Imm, Type *Ty) const override;
>>>>>
>>>>> -  unsigned getIntImmCost(unsigned Opcode, const APInt &Imm,
>>>>> +  unsigned getIntImmCost(unsigned Opcode, unsigned Idx, const APInt &Imm,
>>>>>                          Type *Ty) const override;
>>>>> -  unsigned getIntImmCost(Intrinsic::ID IID, const APInt &Imm,
>>>>> +  unsigned getIntImmCost(Intrinsic::ID IID, unsigned Idx, const APInt &Imm,
>>>>>                          Type *Ty) const override;
>>>>>
>>>>>   /// @}
>>>>> @@ -776,6 +776,9 @@ unsigned X86TTI::getIntImmCost(const API
>>>>>   if (BitSize == 0)
>>>>>     return ~0U;
>>>>>
>>>>> +  if (Imm == 0)
>>>>> +    return TCC_Free;
>>>>> +
>>>>>   if (Imm.getBitWidth() <= 64 &&
>>>>>       (isInt<32>(Imm.getSExtValue()) || isUInt<32>(Imm.getZExtValue())))
>>>>>     return TCC_Basic;
>>>>> @@ -783,7 +786,7 @@ unsigned X86TTI::getIntImmCost(const API
>>>>>     return 2 * TCC_Basic;
>>>>> }
>>>>>
>>>>> -unsigned X86TTI::getIntImmCost(unsigned Opcode, const APInt &Imm,
>>>>> +unsigned X86TTI::getIntImmCost(unsigned Opcode, unsigned Idx, const APInt &Imm,
>>>>>                                Type *Ty) const {
>>>>>   assert(Ty->isIntegerTy());
>>>>>
>>>>> @@ -791,7 +794,15 @@ unsigned X86TTI::getIntImmCost(unsigned
>>>>>   if (BitSize == 0)
>>>>>     return ~0U;
>>>>>
>>>>> +  unsigned ImmIdx = ~0U;
>>>>>   switch (Opcode) {
>>>>> +  default: return TCC_Free;
>>>>> +  case Instruction::GetElementPtr:
>>>>> +    if (Idx != 0)
>>>>> +      return TCC_Free;
>>>>> +  case Instruction::Store:
>>>>> +    ImmIdx = 0;
>>>>> +    break;
>>>>>   case Instruction::Add:
>>>>>   case Instruction::Sub:
>>>>>   case Instruction::Mul:
>>>>> @@ -806,28 +817,31 @@ unsigned X86TTI::getIntImmCost(unsigned
>>>>>   case Instruction::Or:
>>>>>   case Instruction::Xor:
>>>>>   case Instruction::ICmp:
>>>>> -    if (Imm.getBitWidth() <= 64 && isInt<32>(Imm.getSExtValue()))
>>>>> -      return TCC_Free;
>>>>> -    else
>>>>> -      return X86TTI::getIntImmCost(Imm, Ty);
>>>>> +    ImmIdx = 1;
>>>>> +    break;
>>>>>   case Instruction::Trunc:
>>>>>   case Instruction::ZExt:
>>>>>   case Instruction::SExt:
>>>>>   case Instruction::IntToPtr:
>>>>>   case Instruction::PtrToInt:
>>>>>   case Instruction::BitCast:
>>>>> +  case Instruction::PHI:
>>>>>   case Instruction::Call:
>>>>>   case Instruction::Select:
>>>>>   case Instruction::Ret:
>>>>>   case Instruction::Load:
>>>>> -  case Instruction::Store:
>>>>> -    return X86TTI::getIntImmCost(Imm, Ty);
>>>>> +    break;
>>>>>   }
>>>>> -  return TargetTransformInfo::getIntImmCost(Opcode, Imm, Ty);
>>>>> +
>>>>> +  if ((Idx == ImmIdx) &&
>>>>> +      Imm.getBitWidth() <= 64 && isInt<32>(Imm.getSExtValue()))
>>>>> +    return TCC_Free;
>>>>> +
>>>>> +  return X86TTI::getIntImmCost(Imm, Ty);
>>>>> }
>>>>>
>>>>> -unsigned X86TTI::getIntImmCost(Intrinsic::ID IID, const APInt &Imm,
>>>>> -                               Type *Ty) const {
>>>>> +unsigned X86TTI::getIntImmCost(Intrinsic::ID IID, unsigned Idx,
>>>>> +                               const APInt &Imm, Type *Ty) const {
>>>>>   assert(Ty->isIntegerTy());
>>>>>
>>>>>   unsigned BitSize = Ty->getPrimitiveSizeInBits();
>>>>> @@ -835,21 +849,24 @@ unsigned X86TTI::getIntImmCost(Intrinsic
>>>>>     return ~0U;
>>>>>
>>>>>   switch (IID) {
>>>>> -  default: return TargetTransformInfo::getIntImmCost(IID, Imm, Ty);
>>>>> +  default: return TCC_Free;
>>>>>   case Intrinsic::sadd_with_overflow:
>>>>>   case Intrinsic::uadd_with_overflow:
>>>>>   case Intrinsic::ssub_with_overflow:
>>>>>   case Intrinsic::usub_with_overflow:
>>>>>   case Intrinsic::smul_with_overflow:
>>>>>   case Intrinsic::umul_with_overflow:
>>>>> -    if (Imm.getBitWidth() <= 64 && isInt<32>(Imm.getSExtValue()))
>>>>> +    if ((Idx == 1) && Imm.getBitWidth() <= 64 && isInt<32>(Imm.getSExtValue()))
>>>>>       return TCC_Free;
>>>>>     else
>>>>>       return X86TTI::getIntImmCost(Imm, Ty);
>>>>>   case Intrinsic::experimental_stackmap:
>>>>> +    if (Idx < 2)
>>>>> +      return TCC_Free;
>>>>>   case Intrinsic::experimental_patchpoint_void:
>>>>>   case Intrinsic::experimental_patchpoint_i64:
>>>>> -    if (Imm.getBitWidth() <= 64 && isInt<64>(Imm.getSExtValue()))
>>>>> +    if ((Idx < 4 ) ||
>>>>> +        (Imm.getBitWidth() <= 64 && isInt<64>(Imm.getSExtValue())))
>>>>>       return TCC_Free;
>>>>>     else
>>>>>       return X86TTI::getIntImmCost(Imm, Ty);
>>>>>
>>>>> Modified: llvm/trunk/lib/Transforms/Scalar/ConstantHoisting.cpp
>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/ConstantHoisting.cpp?rev=204389&r1=204388&r2=204389&view=diff
>>>>> ==============================================================================
>>>>> --- llvm/trunk/lib/Transforms/Scalar/ConstantHoisting.cpp (original)
>>>>> +++ llvm/trunk/lib/Transforms/Scalar/ConstantHoisting.cpp Thu Mar 20 14:55:52 2014
>>>>> @@ -35,15 +35,14 @@
>>>>>
>>>>> #define DEBUG_TYPE "consthoist"
>>>>> #include "llvm/Transforms/Scalar.h"
>>>>> -#include "llvm/ADT/MapVector.h"
>>>>> #include "llvm/ADT/SmallSet.h"
>>>>> +#include "llvm/ADT/SmallVector.h"
>>>>> #include "llvm/ADT/Statistic.h"
>>>>> #include "llvm/Analysis/TargetTransformInfo.h"
>>>>> #include "llvm/IR/Constants.h"
>>>>> #include "llvm/IR/Dominators.h"
>>>>> #include "llvm/IR/IntrinsicInst.h"
>>>>> #include "llvm/Pass.h"
>>>>> -#include "llvm/Support/CommandLine.h"
>>>>> #include "llvm/Support/Debug.h"
>>>>>
>>>>> using namespace llvm;
>>>>> @@ -51,42 +50,80 @@ using namespace llvm;
>>>>> STATISTIC(NumConstantsHoisted, "Number of constants hoisted");
>>>>> STATISTIC(NumConstantsRebased, "Number of constants rebased");
>>>>>
>>>>> -
>>>>> namespace {
>>>>> -typedef SmallVector<User *, 4> ConstantUseListType;
>>>>> +struct ConstantUser;
>>>>> +struct RebasedConstantInfo;
>>>>> +
>>>>> +typedef SmallVector<ConstantUser, 8> ConstantUseListType;
>>>>> +typedef SmallVector<RebasedConstantInfo, 4> RebasedConstantListType;
>>>>> +
>>>>> +/// \brief Keeps track of the user of a constant and the operand index where the
>>>>> +/// constant is used.
>>>>> +struct ConstantUser {
>>>>> +  Instruction *Inst;
>>>>> +  unsigned OpndIdx;
>>>>> +
>>>>> +  ConstantUser(Instruction *Inst, unsigned Idx) : Inst(Inst), OpndIdx(Idx) { }
>>>>> +};
>>>>> +
>>>>> +/// \brief Keeps track of a constant candidate and its usees.
>>>>> struct ConstantCandidate {
>>>>> +  ConstantUseListType Uses;
>>>>> +  ConstantInt *ConstInt;
>>>>>   unsigned CumulativeCost;
>>>>> +
>>>>> +  ConstantCandidate(ConstantInt *ConstInt)
>>>>> +    : ConstInt(ConstInt), CumulativeCost(0) { }
>>>>> +
>>>>> +  /// \brief Add the user to the use list and update the cost.
>>>>> +  void addUser(Instruction *Inst, unsigned Idx, unsigned Cost) {
>>>>> +    CumulativeCost += Cost;
>>>>> +    Uses.push_back(ConstantUser(Inst, Idx));
>>>>> +  }
>>>>> +};
>>>>> +
>>>>> +/// \brief This represents a constant that has been rebased with respect to a
>>>>> +/// base constant. The difference to the base constant is recorded in Offset.
>>>>> +struct RebasedConstantInfo {
>>>>>   ConstantUseListType Uses;
>>>>> +  Constant *Offset;
>>>>> +  mutable BasicBlock *IDom;
>>>>> +
>>>>> +  RebasedConstantInfo(ConstantUseListType &&Uses, Constant *Offset)
>>>>> +    : Uses(Uses), Offset(Offset), IDom(nullptr) { }
>>>>> };
>>>>>
>>>>> +/// \brief A base constant and all its rebased constants.
>>>>> struct ConstantInfo {
>>>>>   ConstantInt *BaseConstant;
>>>>> -  struct RebasedConstantInfo {
>>>>> -    ConstantInt *OriginalConstant;
>>>>> -    Constant *Offset;
>>>>> -    ConstantUseListType Uses;
>>>>> -  };
>>>>> -  typedef SmallVector<RebasedConstantInfo, 4> RebasedConstantListType;
>>>>>   RebasedConstantListType RebasedConstants;
>>>>> };
>>>>>
>>>>> +/// \brief The constant hoisting pass.
>>>>> class ConstantHoisting : public FunctionPass {
>>>>> +  typedef DenseMap<ConstantInt *, unsigned> ConstCandMapType;
>>>>> +  typedef std::vector<ConstantCandidate> ConstCandVecType;
>>>>> +
>>>>>   const TargetTransformInfo *TTI;
>>>>>   DominatorTree *DT;
>>>>> +  BasicBlock *Entry;
>>>>> +
>>>>> +  /// Keeps track of constant candidates found in the function.
>>>>> +  ConstCandMapType ConstCandMap;
>>>>> +  ConstCandVecType ConstCandVec;
>>>>>
>>>>> -  /// Keeps track of expensive constants found in the function.
>>>>> -  typedef MapVector<ConstantInt *, ConstantCandidate> ConstantMapType;
>>>>> -  ConstantMapType ConstantMap;
>>>>> +  /// Keep track of cast instructions we already cloned.
>>>>> +  SmallDenseMap<Instruction *, Instruction *> ClonedCastMap;
>>>>>
>>>>>   /// These are the final constants we decided to hoist.
>>>>> -  SmallVector<ConstantInfo, 4> Constants;
>>>>> +  SmallVector<ConstantInfo, 8> ConstantVec;
>>>>> public:
>>>>>   static char ID; // Pass identification, replacement for typeid
>>>>> -  ConstantHoisting() : FunctionPass(ID), TTI(0) {
>>>>> +  ConstantHoisting() : FunctionPass(ID), TTI(0), DT(0), Entry(0) {
>>>>>     initializeConstantHoistingPass(*PassRegistry::getPassRegistry());
>>>>>   }
>>>>>
>>>>> -  bool runOnFunction(Function &F) override;
>>>>> +  bool runOnFunction(Function &Fn) override;
>>>>>
>>>>>   const char *getPassName() const override { return "Constant Hoisting"; }
>>>>>
>>>>> @@ -97,19 +134,49 @@ public:
>>>>>   }
>>>>>
>>>>> private:
>>>>> -  void CollectConstant(User *U, unsigned Opcode, Intrinsic::ID IID,
>>>>> -                        ConstantInt *C);
>>>>> -  void CollectConstants(Instruction *I);
>>>>> -  void CollectConstants(Function &F);
>>>>> -  void FindAndMakeBaseConstant(ConstantMapType::iterator S,
>>>>> -                               ConstantMapType::iterator E);
>>>>> -  void FindBaseConstants();
>>>>> -  Instruction *FindConstantInsertionPoint(Function &F,
>>>>> -                                          const ConstantInfo &CI) const;
>>>>> -  void EmitBaseConstants(Function &F, User *U, Instruction *Base,
>>>>> -                         Constant *Offset, ConstantInt *OriginalConstant);
>>>>> -  bool EmitBaseConstants(Function &F);
>>>>> -  bool OptimizeConstants(Function &F);
>>>>> +  /// \brief Initialize the pass.
>>>>> +  void setup(Function &Fn) {
>>>>> +    DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
>>>>> +    TTI = &getAnalysis<TargetTransformInfo>();
>>>>> +    Entry = &Fn.getEntryBlock();
>>>>> +  }
>>>>> +
>>>>> +  /// \brief Cleanup.
>>>>> +  void cleanup() {
>>>>> +    ConstantVec.clear();
>>>>> +    ClonedCastMap.clear();
>>>>> +    ConstCandVec.clear();
>>>>> +    ConstCandMap.clear();
>>>>> +
>>>>> +    TTI = nullptr;
>>>>> +    DT = nullptr;
>>>>> +    Entry = nullptr;
>>>>> +  }
>>>>> +
>>>>> +  /// \brief Find the common dominator of all uses and cache the result for
>>>>> +  /// future lookup.
>>>>> +  BasicBlock *getIDom(const RebasedConstantInfo &RCI) const {
>>>>> +    if (RCI.IDom)
>>>>> +      return RCI.IDom;
>>>>> +    RCI.IDom = findIDomOfAllUses(RCI.Uses);
>>>>> +    assert(RCI.IDom && "Invalid IDom.");
>>>>> +    return RCI.IDom;
>>>>> +  }
>>>>> +
>>>>> +  BasicBlock *findIDomOfAllUses(const ConstantUseListType &Uses) const;
>>>>> +  Instruction *findMatInsertPt(Instruction *I, unsigned Idx = ~0U) const;
>>>>> +  Instruction *findConstantInsertionPoint(const ConstantInfo &CI) const;
>>>>> +  void collectConstantCandidates(Instruction *I, unsigned Idx, ConstantInt *C);
>>>>> +  void collectConstantCandidates(Instruction *I);
>>>>> +  void collectConstantCandidates(Function &Fn);
>>>>> +  void findAndMakeBaseConstant(ConstCandVecType::iterator S,
>>>>> +                               ConstCandVecType::iterator E);
>>>>> +  void findBaseConstants();
>>>>> +  void emitBaseConstants(Instruction *Base, Constant *Offset,
>>>>> +                         const ConstantUser &CU);
>>>>> +  bool emitBaseConstants();
>>>>> +  void deleteDeadCastInst() const;
>>>>> +  bool optimizeConstants(Function &F);
>>>>> };
>>>>> }
>>>>>
>>>>> @@ -126,297 +193,352 @@ FunctionPass *llvm::createConstantHoisti
>>>>> }
>>>>>
>>>>> /// \brief Perform the constant hoisting optimization for the given function.
>>>>> -bool ConstantHoisting::runOnFunction(Function &F) {
>>>>> -  DEBUG(dbgs() << "********** Constant Hoisting **********\n");
>>>>> -  DEBUG(dbgs() << "********** Function: " << F.getName() << '\n');
>>>>> +bool ConstantHoisting::runOnFunction(Function &Fn) {
>>>>> +  DEBUG(dbgs() << "********** Begin Constant Hoisting **********\n");
>>>>> +  DEBUG(dbgs() << "********** Function: " << Fn.getName() << '\n');
>>>>>
>>>>> -  DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
>>>>> -  TTI = &getAnalysis<TargetTransformInfo>();
>>>>> +  setup(Fn);
>>>>>
>>>>> -  return OptimizeConstants(F);
>>>>> +  bool MadeChange = optimizeConstants(Fn);
>>>>> +
>>>>> +  if (MadeChange) {
>>>>> +    DEBUG(dbgs() << "********** Function after Constant Hoisting: "
>>>>> +                 << Fn.getName() << '\n');
>>>>> +    DEBUG(dbgs() << Fn);
>>>>> +  }
>>>>> +  DEBUG(dbgs() << "********** End Constant Hoisting **********\n");
>>>>> +
>>>>> +  cleanup();
>>>>> +
>>>>> +  return MadeChange;
>>>>> }
>>>>>
>>>>> -void ConstantHoisting::CollectConstant(User * U, unsigned Opcode,
>>>>> -                                       Intrinsic::ID IID, ConstantInt *C) {
>>>>> +/// \brief Find nearest common dominator of all uses.
>>>>> +/// FIXME: Replace this with NearestCommonDominator once it is in common code.
>>>>> +BasicBlock *
>>>>> +ConstantHoisting::findIDomOfAllUses(const ConstantUseListType &Uses) const {
>>>>> +  // Collect all basic blocks.
>>>>> +  SmallPtrSet<BasicBlock *, 8> BBs;
>>>>> +  for (auto const &U : Uses)
>>>>> +    BBs.insert(findMatInsertPt(U.Inst, U.OpndIdx)->getParent());
>>>>> +
>>>>> +  if (BBs.count(Entry))
>>>>> +    return Entry;
>>>>> +
>>>>> +  while (BBs.size() >= 2) {
>>>>> +    BasicBlock *BB, *BB1, *BB2;
>>>>> +    BB1 = *BBs.begin();
>>>>> +    BB2 = *std::next(BBs.begin());
>>>>> +    BB = DT->findNearestCommonDominator(BB1, BB2);
>>>>> +    if (BB == Entry)
>>>>> +      return Entry;
>>>>> +    BBs.erase(BB1);
>>>>> +    BBs.erase(BB2);
>>>>> +    BBs.insert(BB);
>>>>> +  }
>>>>> +  assert((BBs.size() == 1) && "Expected only one element.");
>>>>> +  return *BBs.begin();
>>>>> +}
>>>>> +
>>>>> +/// \brief Find the constant materialization insertion point.
>>>>> +Instruction *ConstantHoisting::findMatInsertPt(Instruction *Inst,
>>>>> +                                               unsigned Idx) const {
>>>>> +  // The simple and common case.
>>>>> +  if (!isa<PHINode>(Inst) && !isa<LandingPadInst>(Inst))
>>>>> +    return Inst;
>>>>> +
>>>>> +  // We can't insert directly before a phi node or landing pad. Insert before
>>>>> +  // the terminator of the incoming or dominating block.
>>>>> +  assert(Entry != Inst->getParent() && "PHI or landing pad in entry block!");
>>>>> +  if (Idx != ~0U && isa<PHINode>(Inst))
>>>>> +    return cast<PHINode>(Inst)->getIncomingBlock(Idx)->getTerminator();
>>>>> +
>>>>> +  BasicBlock *IDom = DT->getNode(Inst->getParent())->getIDom()->getBlock();
>>>>> +  return IDom->getTerminator();
>>>>> +}
>>>>> +
>>>>> +/// \brief Find an insertion point that dominates all uses.
>>>>> +Instruction *ConstantHoisting::
>>>>> +findConstantInsertionPoint(const ConstantInfo &ConstInfo) const {
>>>>> +  assert(!ConstInfo.RebasedConstants.empty() && "Invalid constant info entry.");
>>>>> +  // Collect all IDoms.
>>>>> +  SmallPtrSet<BasicBlock *, 8> BBs;
>>>>> +  for (auto const &RCI : ConstInfo.RebasedConstants)
>>>>> +    BBs.insert(getIDom(RCI));
>>>>> +
>>>>> +  assert(!BBs.empty() && "No dominators!?");
>>>>> +
>>>>> +  if (BBs.count(Entry))
>>>>> +    return &Entry->front();
>>>>> +
>>>>> +  while (BBs.size() >= 2) {
>>>>> +    BasicBlock *BB, *BB1, *BB2;
>>>>> +    BB1 = *BBs.begin();
>>>>> +    BB2 = *std::next(BBs.begin());
>>>>> +    BB = DT->findNearestCommonDominator(BB1, BB2);
>>>>> +    if (BB == Entry)
>>>>> +      return &Entry->front();
>>>>> +    BBs.erase(BB1);
>>>>> +    BBs.erase(BB2);
>>>>> +    BBs.insert(BB);
>>>>> +  }
>>>>> +  assert((BBs.size() == 1) && "Expected only one element.");
>>>>> +  Instruction &FirstInst = (*BBs.begin())->front();
>>>>> +  return findMatInsertPt(&FirstInst);
>>>>> +}
>>>>> +
>>>>> +
>>>>> +/// \brief Record constant integer ConstInt for instruction Inst at operand
>>>>> +/// index Idx.
>>>>> +///
>>>>> +/// The operand at index Idx is not necessarily the constant inetger itself. It
>>>>> +/// could also be a cast instruction or a constant expression that uses the
>>>>> +// constant integer.
>>>>> +void ConstantHoisting::collectConstantCandidates(Instruction *Inst,
>>>>> +                                                 unsigned Idx,
>>>>> +                                                 ConstantInt *ConstInt) {
>>>>>   unsigned Cost;
>>>>> -  if (Opcode)
>>>>> -    Cost = TTI->getIntImmCost(Opcode, C->getValue(), C->getType());
>>>>> +  // Ask the target about the cost of materializing the constant for the given
>>>>> +  // instruction and operand index.
>>>>> +  if (auto IntrInst = dyn_cast<IntrinsicInst>(Inst))
>>>>> +    Cost = TTI->getIntImmCost(IntrInst->getIntrinsicID(), Idx,
>>>>> +                              ConstInt->getValue(), ConstInt->getType());
>>>>>   else
>>>>> -    Cost = TTI->getIntImmCost(IID, C->getValue(), C->getType());
>>>>> +    Cost = TTI->getIntImmCost(Inst->getOpcode(), Idx, ConstInt->getValue(),
>>>>> +                              ConstInt->getType());
>>>>>
>>>>> +  // Ignore cheap integer constants.
>>>>>   if (Cost > TargetTransformInfo::TCC_Basic) {
>>>>> -    ConstantCandidate &CC = ConstantMap[C];
>>>>> -    CC.CumulativeCost += Cost;
>>>>> -    CC.Uses.push_back(U);
>>>>> -    DEBUG(dbgs() << "Collect constant " << *C << " with cost " << Cost
>>>>> -                 << " from " << *U << '\n');
>>>>> +    ConstCandMapType::iterator Itr;
>>>>> +    bool Inserted;
>>>>> +    std::tie(Itr, Inserted) = ConstCandMap.insert(std::make_pair(ConstInt, 0));
>>>>> +    if (Inserted) {
>>>>> +      ConstCandVec.push_back(ConstantCandidate(ConstInt));
>>>>> +      Itr->second = ConstCandVec.size() - 1;
>>>>> +    }
>>>>> +    ConstCandVec[Itr->second].addUser(Inst, Idx, Cost);
>>>>> +    DEBUG(if (auto ConstInt = dyn_cast<ConstantInt>(Inst->getOperand(Idx)))
>>>>> +            dbgs() << "Collect constant " << *ConstInt << " from " << *Inst
>>>>> +                   << " with cost " << Cost << '\n';
>>>>> +          else
>>>>> +          dbgs() << "Collect constant " << *ConstInt << " indirectly from "
>>>>> +                 << *Inst << " via " << *Inst->getOperand(Idx) << " with cost "
>>>>> +                 << Cost << '\n';
>>>>> +    );
>>>>>   }
>>>>> }
>>>>>
>>>>> -/// \brief Scan the instruction or constant expression for expensive integer
>>>>> -/// constants and record them in the constant map.
>>>>> -void ConstantHoisting::CollectConstants(Instruction *I) {
>>>>> -  unsigned Opcode = 0;
>>>>> -  Intrinsic::ID IID = Intrinsic::not_intrinsic;
>>>>> -  if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I))
>>>>> -    IID = II->getIntrinsicID();
>>>>> -  else
>>>>> -    Opcode = I->getOpcode();
>>>>> +/// \brief Scan the instruction for expensive integer constants and record them
>>>>> +/// in the constant candidate vector.
>>>>> +void ConstantHoisting::collectConstantCandidates(Instruction *Inst) {
>>>>> +  // Skip all cast instructions. They are visited indirectly later on.
>>>>> +  if (Inst->isCast())
>>>>> +    return;
>>>>> +
>>>>> +  // Can't handle inline asm. Skip it.
>>>>> +  if (auto Call = dyn_cast<CallInst>(Inst))
>>>>> +    if (isa<InlineAsm>(Call->getCalledValue()))
>>>>> +      return;
>>>>>
>>>>>   // Scan all operands.
>>>>> -  for (User::op_iterator O = I->op_begin(), E = I->op_end(); O != E; ++O) {
>>>>> -    if (ConstantInt *C = dyn_cast<ConstantInt>(O)) {
>>>>> -      CollectConstant(I, Opcode, IID, C);
>>>>> +  for (unsigned Idx = 0, E = Inst->getNumOperands(); Idx != E; ++Idx) {
>>>>> +    Value *Opnd = Inst->getOperand(Idx);
>>>>> +
>>>>> +    // Vist constant integers.
>>>>> +    if (auto ConstInt = dyn_cast<ConstantInt>(Opnd)) {
>>>>> +      collectConstantCandidates(Inst, Idx, ConstInt);
>>>>>       continue;
>>>>>     }
>>>>> -    if (ConstantExpr *CE = dyn_cast<ConstantExpr>(O)) {
>>>>> -      // We only handle constant cast expressions.
>>>>> -      if (!CE->isCast())
>>>>> +
>>>>> +    // Visit cast instructions that have constant integers.
>>>>> +    if (auto CastInst = dyn_cast<Instruction>(Opnd)) {
>>>>> +      // Only visit cast instructions, which have been skipped. All other
>>>>> +      // instructions should have already been visited.
>>>>> +      if (!CastInst->isCast())
>>>>>         continue;
>>>>>
>>>>> -      if (ConstantInt *C = dyn_cast<ConstantInt>(CE->getOperand(0))) {
>>>>> -        // Ignore the cast expression and use the opcode of the instruction.
>>>>> -        CollectConstant(CE, Opcode, IID, C);
>>>>> +      if (auto *ConstInt = dyn_cast<ConstantInt>(CastInst->getOperand(0))) {
>>>>> +        // Pretend the constant is directly used by the instruction and ignore
>>>>> +        // the cast instruction.
>>>>> +        collectConstantCandidates(Inst, Idx, ConstInt);
>>>>>         continue;
>>>>>       }
>>>>>     }
>>>>> -  }
>>>>> +
>>>>> +    // Visit constant expressions that have constant integers.
>>>>> +    if (auto ConstExpr = dyn_cast<ConstantExpr>(Opnd)) {
>>>>> +      // Only visit constant cast expressions.
>>>>> +      if (!ConstExpr->isCast())
>>>>> +        continue;
>>>>> +
>>>>> +      if (auto ConstInt = dyn_cast<ConstantInt>(ConstExpr->getOperand(0))) {
>>>>> +        // Pretend the constant is directly used by the instruction and ignore
>>>>> +        // the constant expression.
>>>>> +        collectConstantCandidates(Inst, Idx, ConstInt);
>>>>> +        continue;
>>>>> +      }
>>>>> +    }
>>>>> +  } // end of for all operands
>>>>> }
>>>>>
>>>>> /// \brief Collect all integer constants in the function that cannot be folded
>>>>> /// into an instruction itself.
>>>>> -void ConstantHoisting::CollectConstants(Function &F) {
>>>>> -  for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
>>>>> -    for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
>>>>> -      CollectConstants(I);
>>>>> +void ConstantHoisting::collectConstantCandidates(Function &Fn) {
>>>>> +  for (Function::iterator BB : Fn)
>>>>> +    for (BasicBlock::iterator I : *BB)
>>>>> +      collectConstantCandidates(I);
>>>>> }
>>>>>
>>>>> /// \brief Find the base constant within the given range and rebase all other
>>>>> /// constants with respect to the base constant.
>>>>> -void ConstantHoisting::FindAndMakeBaseConstant(ConstantMapType::iterator S,
>>>>> -                                               ConstantMapType::iterator E) {
>>>>> -  ConstantMapType::iterator MaxCostItr = S;
>>>>> +void ConstantHoisting::findAndMakeBaseConstant(ConstCandVecType::iterator S,
>>>>> +                                               ConstCandVecType::iterator E) {
>>>>> +  auto MaxCostItr = S;
>>>>>   unsigned NumUses = 0;
>>>>>   // Use the constant that has the maximum cost as base constant.
>>>>> -  for (ConstantMapType::iterator I = S; I != E; ++I) {
>>>>> -    NumUses += I->second.Uses.size();
>>>>> -    if (I->second.CumulativeCost > MaxCostItr->second.CumulativeCost)
>>>>> -      MaxCostItr = I;
>>>>> +  for (auto ConstCand = S; ConstCand != E; ++ConstCand) {
>>>>> +    NumUses += ConstCand->Uses.size();
>>>>> +    if (ConstCand->CumulativeCost > MaxCostItr->CumulativeCost)
>>>>> +      MaxCostItr = ConstCand;
>>>>>   }
>>>>>
>>>>>   // Don't hoist constants that have only one use.
>>>>>   if (NumUses <= 1)
>>>>>     return;
>>>>>
>>>>> -  ConstantInfo CI;
>>>>> -  CI.BaseConstant = MaxCostItr->first;
>>>>> -  Type *Ty = CI.BaseConstant->getType();
>>>>> +  ConstantInfo ConstInfo;
>>>>> +  ConstInfo.BaseConstant = MaxCostItr->ConstInt;
>>>>> +  Type *Ty = ConstInfo.BaseConstant->getType();
>>>>> +
>>>>>   // Rebase the constants with respect to the base constant.
>>>>> -  for (ConstantMapType::iterator I = S; I != E; ++I) {
>>>>> -    APInt Diff = I->first->getValue() - CI.BaseConstant->getValue();
>>>>> -    ConstantInfo::RebasedConstantInfo RCI;
>>>>> -    RCI.OriginalConstant = I->first;
>>>>> -    RCI.Offset = ConstantInt::get(Ty, Diff);
>>>>> -    RCI.Uses = std::move(I->second.Uses);
>>>>> -    CI.RebasedConstants.push_back(RCI);
>>>>> -  }
>>>>> -  Constants.push_back(CI);
>>>>> -}
>>>>> -
>>>>> -/// \brief Finds and combines constants that can be easily rematerialized with
>>>>> -/// an add from a common base constant.
>>>>> -void ConstantHoisting::FindBaseConstants() {
>>>>> -  // Sort the constants by value and type. This invalidates the mapping.
>>>>> -  std::sort(ConstantMap.begin(), ConstantMap.end(),
>>>>> -            [](const std::pair<ConstantInt *, ConstantCandidate> &LHS,
>>>>> -               const std::pair<ConstantInt *, ConstantCandidate> &RHS) {
>>>>> -    if (LHS.first->getType() != RHS.first->getType())
>>>>> -      return LHS.first->getType()->getBitWidth() <
>>>>> -             RHS.first->getType()->getBitWidth();
>>>>> -    return LHS.first->getValue().ult(RHS.first->getValue());
>>>>> -  });
>>>>> -
>>>>> -  // Simple linear scan through the sorted constant map for viable merge
>>>>> -  // candidates.
>>>>> -  ConstantMapType::iterator MinValItr = ConstantMap.begin();
>>>>> -  for (ConstantMapType::iterator I = std::next(ConstantMap.begin()),
>>>>> -       E = ConstantMap.end(); I != E; ++I) {
>>>>> -    if (MinValItr->first->getType() == I->first->getType()) {
>>>>> +  for (auto ConstCand = S; ConstCand != E; ++ConstCand) {
>>>>> +    APInt Diff = ConstCand->ConstInt->getValue() -
>>>>> +                 ConstInfo.BaseConstant->getValue();
>>>>> +    Constant *Offset = Diff == 0 ? nullptr : ConstantInt::get(Ty, Diff);
>>>>> +    ConstInfo.RebasedConstants.push_back(
>>>>> +      RebasedConstantInfo(std::move(ConstCand->Uses), Offset));
>>>>> +  }
>>>>> +  ConstantVec.push_back(ConstInfo);
>>>>> +}
>>>>> +
>>>>> +/// \brief Finds and combines constant candidates that can be easily
>>>>> +/// rematerialized with an add from a common base constant.
>>>>> +void ConstantHoisting::findBaseConstants() {
>>>>> +  // Sort the constants by value and type. This invalidates the mapping!
>>>>> +  std::sort(ConstCandVec.begin(), ConstCandVec.end(),
>>>>> +            [](const ConstantCandidate &LHS, const ConstantCandidate &RHS) {
>>>>> +              if (LHS.ConstInt->getType() != RHS.ConstInt->getType())
>>>>> +                return LHS.ConstInt->getType()->getBitWidth() <
>>>>> +                       RHS.ConstInt->getType()->getBitWidth();
>>>>> +              return LHS.ConstInt->getValue().ult(RHS.ConstInt->getValue());
>>>>> +            });
>>>>> +
>>>>> +  // Simple linear scan through the sorted constant candidate vector for viable
>>>>> +  // merge candidates.
>>>>> +  auto MinValItr = ConstCandVec.begin();
>>>>> +  for (auto CC = std::next(ConstCandVec.begin()), E = ConstCandVec.end();
>>>>> +       CC != E; ++CC) {
>>>>> +    if (MinValItr->ConstInt->getType() == CC->ConstInt->getType()) {
>>>>>       // Check if the constant is in range of an add with immediate.
>>>>> -      APInt Diff = I->first->getValue() - MinValItr->first->getValue();
>>>>> +      APInt Diff = CC->ConstInt->getValue() - MinValItr->ConstInt->getValue();
>>>>>       if ((Diff.getBitWidth() <= 64) &&
>>>>>           TTI->isLegalAddImmediate(Diff.getSExtValue()))
>>>>>         continue;
>>>>>     }
>>>>>     // We either have now a different constant type or the constant is not in
>>>>>     // range of an add with immediate anymore.
>>>>> -    FindAndMakeBaseConstant(MinValItr, I);
>>>>> +    findAndMakeBaseConstant(MinValItr, CC);
>>>>>     // Start a new base constant search.
>>>>> -    MinValItr = I;
>>>>> +    MinValItr = CC;
>>>>>   }
>>>>>   // Finalize the last base constant search.
>>>>> -  FindAndMakeBaseConstant(MinValItr, ConstantMap.end());
>>>>> -}
>>>>> -
>>>>> -/// \brief Records the basic block of the instruction or all basic blocks of the
>>>>> -/// users of the constant expression.
>>>>> -static void CollectBasicBlocks(SmallPtrSet<BasicBlock *, 4> &BBs, Function &F,
>>>>> -                               User *U) {
>>>>> -  if (Instruction *I = dyn_cast<Instruction>(U))
>>>>> -    BBs.insert(I->getParent());
>>>>> -  else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(U))
>>>>> -    // Find all users of this constant expression.
>>>>> -    for (User *UU : CE->users())
>>>>> -      // Only record users that are instructions. We don't want to go down a
>>>>> -      // nested constant expression chain. Also check if the instruction is even
>>>>> -      // in the current function.
>>>>> -      if (Instruction *I = dyn_cast<Instruction>(UU))
>>>>> -        if(I->getParent()->getParent() == &F)
>>>>> -          BBs.insert(I->getParent());
>>>>> -}
>>>>> -
>>>>> -/// \brief Find the instruction we should insert the constant materialization
>>>>> -/// before.
>>>>> -static Instruction *getMatInsertPt(Instruction *I, const DominatorTree *DT) {
>>>>> -  if (!isa<PHINode>(I) && !isa<LandingPadInst>(I)) // Simple case.
>>>>> -    return I;
>>>>> -
>>>>> -  // We can't insert directly before a phi node or landing pad. Insert before
>>>>> -  // the terminator of the dominating block.
>>>>> -  assert(&I->getParent()->getParent()->getEntryBlock() != I->getParent() &&
>>>>> -         "PHI or landing pad in entry block!");
>>>>> -  BasicBlock *IDom = DT->getNode(I->getParent())->getIDom()->getBlock();
>>>>> -  return IDom->getTerminator();
>>>>> -}
>>>>> -
>>>>> -/// \brief Find an insertion point that dominates all uses.
>>>>> -Instruction *ConstantHoisting::
>>>>> -FindConstantInsertionPoint(Function &F, const ConstantInfo &CI) const {
>>>>> -  BasicBlock *Entry = &F.getEntryBlock();
>>>>> -
>>>>> -  // Collect all basic blocks.
>>>>> -  SmallPtrSet<BasicBlock *, 4> BBs;
>>>>> -  ConstantInfo::RebasedConstantListType::const_iterator RCI, RCE;
>>>>> -  for (RCI = CI.RebasedConstants.begin(), RCE = CI.RebasedConstants.end();
>>>>> -       RCI != RCE; ++RCI)
>>>>> -    for (SmallVectorImpl<User *>::const_iterator U = RCI->Uses.begin(),
>>>>> -         E = RCI->Uses.end(); U != E; ++U)
>>>>> -      CollectBasicBlocks(BBs, F, *U);
>>>>> -
>>>>> -  if (BBs.count(Entry))
>>>>> -    return getMatInsertPt(&Entry->front(), DT);
>>>>> -
>>>>> -  while (BBs.size() >= 2) {
>>>>> -    BasicBlock *BB, *BB1, *BB2;
>>>>> -    BB1 = *BBs.begin();
>>>>> -    BB2 = *std::next(BBs.begin());
>>>>> -    BB = DT->findNearestCommonDominator(BB1, BB2);
>>>>> -    if (BB == Entry)
>>>>> -      return getMatInsertPt(&Entry->front(), DT);
>>>>> -    BBs.erase(BB1);
>>>>> -    BBs.erase(BB2);
>>>>> -    BBs.insert(BB);
>>>>> -  }
>>>>> -  assert((BBs.size() == 1) && "Expected only one element.");
>>>>> -  Instruction &FirstInst = (*BBs.begin())->front();
>>>>> -  return getMatInsertPt(&FirstInst, DT);
>>>>> +  findAndMakeBaseConstant(MinValItr, ConstCandVec.end());
>>>>> }
>>>>>
>>>>> /// \brief Emit materialization code for all rebased constants and update their
>>>>> /// users.
>>>>> -void ConstantHoisting::EmitBaseConstants(Function &F, User *U,
>>>>> -                                         Instruction *Base, Constant *Offset,
>>>>> -                                         ConstantInt *OriginalConstant) {
>>>>> -  if (Instruction *I = dyn_cast<Instruction>(U)) {
>>>>> -    Instruction *Mat = Base;
>>>>> -    if (!Offset->isNullValue()) {
>>>>> -      Mat = BinaryOperator::Create(Instruction::Add, Base, Offset,
>>>>> -                                   "const_mat", getMatInsertPt(I, DT));
>>>>> -
>>>>> -      // Use the same debug location as the instruction we are about to update.
>>>>> -      Mat->setDebugLoc(I->getDebugLoc());
>>>>> -
>>>>> -      DEBUG(dbgs() << "Materialize constant (" << *Base->getOperand(0)
>>>>> -                   << " + " << *Offset << ") in BB "
>>>>> -                   << I->getParent()->getName() << '\n' << *Mat << '\n');
>>>>> -    }
>>>>> -    DEBUG(dbgs() << "Update: " << *I << '\n');
>>>>> -    I->replaceUsesOfWith(OriginalConstant, Mat);
>>>>> -    DEBUG(dbgs() << "To: " << *I << '\n');
>>>>> +void ConstantHoisting::emitBaseConstants(Instruction *Base, Constant *Offset,
>>>>> +                                         const ConstantUser &CU) {
>>>>> +  Instruction *Mat = Base;
>>>>> +  if (Offset) {
>>>>> +    Instruction *InsertionPt = findMatInsertPt(CU.Inst, CU.OpndIdx);
>>>>> +    Mat = BinaryOperator::Create(Instruction::Add, Base, Offset,
>>>>> +                                 "const_mat", InsertionPt);
>>>>> +
>>>>> +    DEBUG(dbgs() << "Materialize constant (" << *Base->getOperand(0)
>>>>> +                 << " + " << *Offset << ") in BB "
>>>>> +                 << Mat->getParent()->getName() << '\n' << *Mat << '\n');
>>>>> +    Mat->setDebugLoc(CU.Inst->getDebugLoc());
>>>>> +  }
>>>>> +  Value *Opnd = CU.Inst->getOperand(CU.OpndIdx);
>>>>> +
>>>>> +  // Visit constant integer.
>>>>> +  if (isa<ConstantInt>(Opnd)) {
>>>>> +    DEBUG(dbgs() << "Update: " << *CU.Inst << '\n');
>>>>> +    CU.Inst->setOperand(CU.OpndIdx, Mat);
>>>>> +    DEBUG(dbgs() << "To    : " << *CU.Inst << '\n');
>>>>>     return;
>>>>>   }
>>>>> -  assert(isa<ConstantExpr>(U) && "Expected a ConstantExpr.");
>>>>> -  ConstantExpr *CE = cast<ConstantExpr>(U);
>>>>> -  SmallVector<std::pair<Instruction *, Instruction *>, 8> WorkList;
>>>>> -  DEBUG(dbgs() << "Visit ConstantExpr " << *CE << '\n');
>>>>> -  for (User *UU : CE->users()) {
>>>>> -    DEBUG(dbgs() << "Check user "; UU->print(dbgs()); dbgs() << '\n');
>>>>> -    // We only handel instructions here and won't walk down a ConstantExpr chain
>>>>> -    // to replace all ConstExpr with instructions.
>>>>> -    if (Instruction *I = dyn_cast<Instruction>(UU)) {
>>>>> -      // Only update constant expressions in the current function.
>>>>> -      if (I->getParent()->getParent() != &F) {
>>>>> -        DEBUG(dbgs() << "Not in the same function - skip.\n");
>>>>> -        continue;
>>>>> -      }
>>>>>
>>>>> -      Instruction *Mat = Base;
>>>>> -      Instruction *InsertBefore = getMatInsertPt(I, DT);
>>>>> -      if (!Offset->isNullValue()) {
>>>>> -        Mat = BinaryOperator::Create(Instruction::Add, Base, Offset,
>>>>> -                                     "const_mat", InsertBefore);
>>>>> -
>>>>> -        // Use the same debug location as the instruction we are about to
>>>>> -        // update.
>>>>> -        Mat->setDebugLoc(I->getDebugLoc());
>>>>> -
>>>>> -        DEBUG(dbgs() << "Materialize constant (" << *Base->getOperand(0)
>>>>> -                     << " + " << *Offset << ") in BB "
>>>>> -                     << I->getParent()->getName() << '\n' << *Mat << '\n');
>>>>> -      }
>>>>> -      Instruction *ICE = CE->getAsInstruction();
>>>>> -      ICE->replaceUsesOfWith(OriginalConstant, Mat);
>>>>> -      ICE->insertBefore(InsertBefore);
>>>>> -
>>>>> -      // Use the same debug location as the instruction we are about to update.
>>>>> -      ICE->setDebugLoc(I->getDebugLoc());
>>>>> -
>>>>> -      WorkList.push_back(std::make_pair(I, ICE));
>>>>> -    } else {
>>>>> -      DEBUG(dbgs() << "Not an instruction - skip.\n");
>>>>> +  // Visit cast instruction.
>>>>> +  if (auto CastInst = dyn_cast<Instruction>(Opnd)) {
>>>>> +    assert(CastInst->isCast() && "Expected an cast instruction!");
>>>>> +    // Check if we already have visited this cast instruction before to avoid
>>>>> +    // unnecessary cloning.
>>>>> +    Instruction *&ClonedCastInst = ClonedCastMap[CastInst];
>>>>> +    if (!ClonedCastInst) {
>>>>> +      ClonedCastInst = CastInst->clone();
>>>>> +      ClonedCastInst->setOperand(0, Mat);
>>>>> +      ClonedCastInst->insertAfter(CastInst);
>>>>> +      // Use the same debug location as the original cast instruction.
>>>>> +      ClonedCastInst->setDebugLoc(CastInst->getDebugLoc());
>>>>> +      DEBUG(dbgs() << "Clone instruction: " << *ClonedCastInst << '\n'
>>>>> +                   << "To               : " << *CastInst << '\n');
>>>>>     }
>>>>> +
>>>>> +    DEBUG(dbgs() << "Update: " << *CU.Inst << '\n');
>>>>> +    CU.Inst->setOperand(CU.OpndIdx, ClonedCastInst);
>>>>> +    DEBUG(dbgs() << "To    : " << *CU.Inst << '\n');
>>>>> +    return;
>>>>>   }
>>>>> -  SmallVectorImpl<std::pair<Instruction *, Instruction *> >::iterator I, E;
>>>>> -  for (I = WorkList.begin(), E = WorkList.end(); I != E; ++I) {
>>>>> -    DEBUG(dbgs() << "Create instruction: " << *I->second << '\n');
>>>>> -    DEBUG(dbgs() << "Update: " << *I->first << '\n');
>>>>> -    I->first->replaceUsesOfWith(CE, I->second);
>>>>> -    DEBUG(dbgs() << "To: " << *I->first << '\n');
>>>>> +
>>>>> +  // Visit constant expression.
>>>>> +  if (auto ConstExpr = dyn_cast<ConstantExpr>(Opnd)) {
>>>>> +    Instruction *ConstExprInst = ConstExpr->getAsInstruction();
>>>>> +    ConstExprInst->setOperand(0, Mat);
>>>>> +    ConstExprInst->insertBefore(findMatInsertPt(CU.Inst, CU.OpndIdx));
>>>>> +
>>>>> +    // Use the same debug location as the instruction we are about to update.
>>>>> +    ConstExprInst->setDebugLoc(CU.Inst->getDebugLoc());
>>>>> +
>>>>> +    DEBUG(dbgs() << "Create instruction: " << *ConstExprInst << '\n'
>>>>> +                 << "From              : " << *ConstExpr << '\n');
>>>>> +    DEBUG(dbgs() << "Update: " << *CU.Inst << '\n');
>>>>> +    CU.Inst->setOperand(CU.OpndIdx, ConstExprInst);
>>>>> +    DEBUG(dbgs() << "To    : " << *CU.Inst << '\n');
>>>>> +    return;
>>>>>   }
>>>>> }
>>>>>
>>>>> /// \brief Hoist and hide the base constant behind a bitcast and emit
>>>>> /// materialization code for derived constants.
>>>>> -bool ConstantHoisting::EmitBaseConstants(Function &F) {
>>>>> +bool ConstantHoisting::emitBaseConstants() {
>>>>>   bool MadeChange = false;
>>>>> -  SmallVectorImpl<ConstantInfo>::iterator CI, CE;
>>>>> -  for (CI = Constants.begin(), CE = Constants.end(); CI != CE; ++CI) {
>>>>> +  for (auto const &ConstInfo : ConstantVec) {
>>>>>     // Hoist and hide the base constant behind a bitcast.
>>>>> -    Instruction *IP = FindConstantInsertionPoint(F, *CI);
>>>>> -    IntegerType *Ty = CI->BaseConstant->getType();
>>>>> -    Instruction *Base = new BitCastInst(CI->BaseConstant, Ty, "const", IP);
>>>>> -    DEBUG(dbgs() << "Hoist constant (" << *CI->BaseConstant << ") to BB "
>>>>> -                 << IP->getParent()->getName() << '\n');
>>>>> +    Instruction *IP = findConstantInsertionPoint(ConstInfo);
>>>>> +    IntegerType *Ty = ConstInfo.BaseConstant->getType();
>>>>> +    Instruction *Base =
>>>>> +      new BitCastInst(ConstInfo.BaseConstant, Ty, "const", IP);
>>>>> +    DEBUG(dbgs() << "Hoist constant (" << *ConstInfo.BaseConstant << ") to BB "
>>>>> +                 << IP->getParent()->getName() << '\n' << *Base << '\n');
>>>>>     NumConstantsHoisted++;
>>>>>
>>>>>     // Emit materialization code for all rebased constants.
>>>>> -    ConstantInfo::RebasedConstantListType::iterator RCI, RCE;
>>>>> -    for (RCI = CI->RebasedConstants.begin(), RCE = CI->RebasedConstants.end();
>>>>> -         RCI != RCE; ++RCI) {
>>>>> +    for (auto const &RCI : ConstInfo.RebasedConstants) {
>>>>>       NumConstantsRebased++;
>>>>> -      for (SmallVectorImpl<User *>::iterator U = RCI->Uses.begin(),
>>>>> -           E = RCI->Uses.end(); U != E; ++U)
>>>>> -        EmitBaseConstants(F, *U, Base, RCI->Offset, RCI->OriginalConstant);
>>>>> +      for (auto const &U : RCI.Uses)
>>>>> +        emitBaseConstants(Base, RCI.Offset, U);
>>>>>     }
>>>>>
>>>>>     // Use the same debug location as the last user of the constant.
>>>>> @@ -432,27 +554,37 @@ bool ConstantHoisting::EmitBaseConstants
>>>>>   return MadeChange;
>>>>> }
>>>>>
>>>>> -/// \brief Optimize expensive integer constants in the given function.
>>>>> -bool ConstantHoisting::OptimizeConstants(Function &F) {
>>>>> -  bool MadeChange = false;
>>>>> +/// \brief Check all cast instructions we made a copy of and remove them if they
>>>>> +/// have no more users.
>>>>> +void ConstantHoisting::deleteDeadCastInst() const {
>>>>> +  for (auto const &I : ClonedCastMap)
>>>>> +    if (I.first->use_empty())
>>>>> +      I.first->removeFromParent();
>>>>> +}
>>>>>
>>>>> +/// \brief Optimize expensive integer constants in the given function.
>>>>> +bool ConstantHoisting::optimizeConstants(Function &Fn) {
>>>>>   // Collect all constant candidates.
>>>>> -  CollectConstants(F);
>>>>> +  collectConstantCandidates(Fn);
>>>>>
>>>>> -  // There are no constants to worry about.
>>>>> -  if (ConstantMap.empty())
>>>>> -    return MadeChange;
>>>>> +  // There are no constant candidates to worry about.
>>>>> +  if (ConstCandVec.empty())
>>>>> +    return false;
>>>>>
>>>>>   // Combine constants that can be easily materialized with an add from a common
>>>>>   // base constant.
>>>>> -  FindBaseConstants();
>>>>> +  findBaseConstants();
>>>>> +
>>>>> +  // There are no constants to emit.
>>>>> +  if (ConstantVec.empty())
>>>>> +    return false;
>>>>>
>>>>>   // Finally hoist the base constant and emit materializating code for dependent
>>>>>   // constants.
>>>>> -  MadeChange |= EmitBaseConstants(F);
>>>>> +  bool MadeChange = emitBaseConstants();
>>>>>
>>>>> -  ConstantMap.clear();
>>>>> -  Constants.clear();
>>>>> +  // Cleanup dead instructions.
>>>>> +  deleteDeadCastInst();
>>>>>
>>>>>   return MadeChange;
>>>>> }
>>>>>
>>>>> Modified: llvm/trunk/test/CodeGen/X86/lsr-interesting-step.ll
>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/lsr-interesting-step.ll?rev=204389&r1=204388&r2=204389&view=diff
>>>>> ==============================================================================
>>>>> --- llvm/trunk/test/CodeGen/X86/lsr-interesting-step.ll (original)
>>>>> +++ llvm/trunk/test/CodeGen/X86/lsr-interesting-step.ll Thu Mar 20 14:55:52 2014
>>>>> @@ -3,26 +3,24 @@
>>>>> ; The inner loop should require only one add (and no leas either).
>>>>> ; rdar://8100380
>>>>>
>>>>> -; CHECK:      BB0_3:
>>>>> -; CHECK-NEXT:   movb    $0, flags(%rdx)
>>>>> -; CHECK-NEXT:   addq    %rax, %rdx
>>>>> -; CHECK-NEXT:   cmpq    $8192, %rdx
>>>>> +; CHECK:      BB0_2:
>>>>> +; CHECK-NEXT:   movb    $0, flags(%rcx)
>>>>> +; CHECK-NEXT:   addq    %rax, %rcx
>>>>> +; CHECK-NEXT:   cmpq    $8192, %rcx
>>>>> ; CHECK-NEXT:   jl
>>>>>
>>>>> @flags = external global [8192 x i8], align 16 ; <[8192 x i8]*> [#uses=1]
>>>>>
>>>>> define void @foo() nounwind {
>>>>> entry:
>>>>> -  %tmp = icmp slt i64 2, 8192                     ; <i1> [#uses=1]
>>>>> -  br i1 %tmp, label %bb, label %bb21
>>>>> +  br label %bb
>>>>>
>>>>> bb:                                               ; preds = %entry
>>>>>   br label %bb7
>>>>>
>>>>> bb7:                                              ; preds = %bb, %bb17
>>>>>   %tmp8 = phi i64 [ %tmp18, %bb17 ], [ 2, %bb ]   ; <i64> [#uses=2]
>>>>> -  %tmp9 = icmp slt i64 2, 8192                    ; <i1> [#uses=1]
>>>>> -  br i1 %tmp9, label %bb10, label %bb17
>>>>> +  br label %bb10
>>>>>
>>>>> bb10:                                             ; preds = %bb7
>>>>>   br label %bb11
>>>>>
>>>>> Modified: llvm/trunk/test/CodeGen/X86/negate-add-zero.ll
>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/negate-add-zero.ll?rev=204389&r1=204388&r2=204389&view=diff
>>>>> ==============================================================================
>>>>> --- llvm/trunk/test/CodeGen/X86/negate-add-zero.ll (original)
>>>>> +++ llvm/trunk/test/CodeGen/X86/negate-add-zero.ll Thu Mar 20 14:55:52 2014
>>>>> @@ -827,9 +827,7 @@ declare void @_ZN11MatrixTools9transpose
>>>>> declare void @_ZN21HNodeTranslateRotate311toCartesianEv(%struct.HNodeTranslateRotate3*)
>>>>>
>>>>> define linkonce void @_ZN21HNodeTranslateRotate36setVelERK9CDSVectorIdLi1EN3CDS12DefaultAllocEE(%struct.HNodeTranslateRotate3* %this, %"struct.CDSVector<double,0,CDS::DefaultAlloc>"* %velv) {
>>>>> -entry:
>>>>> -       %0 = add i32 0, -1              ; <i32> [#uses=1]
>>>>> -       %1 = getelementptr double* null, i32 %0         ; <double*> [#uses=1]
>>>>> +       %1 = getelementptr double* null, i32 -1         ; <double*> [#uses=1]
>>>>>        %2 = load double* %1, align 8           ; <double> [#uses=1]
>>>>>        %3 = load double* null, align 8         ; <double> [#uses=2]
>>>>>        %4 = load double* null, align 8         ; <double> [#uses=2]
>>>>> @@ -890,13 +888,12 @@ entry:
>>>>>        store double %52, double* %55, align 8
>>>>>        %56 = getelementptr %struct.HNodeTranslateRotate3* %this, i32 0, i32 0, i32 10, i32 0, i32 0, i32 2             ; <double*> [#uses=1]
>>>>>        store double %53, double* %56, align 8
>>>>> -       %57 = add i32 0, 4              ; <i32> [#uses=1]
>>>>> -       %58 = getelementptr %"struct.SubVector<CDSVector<double, 1, CDS::DefaultAlloc> >"* null, i32 0, i32 0           ; <%"struct.CDSVector<double,0,CDS::DefaultAlloc>"**> [#uses=1]
>>>>> -       store %"struct.CDSVector<double,0,CDS::DefaultAlloc>"* %velv, %"struct.CDSVector<double,0,CDS::DefaultAlloc>"** %58, align 8
>>>>> -       %59 = getelementptr %"struct.SubVector<CDSVector<double, 1, CDS::DefaultAlloc> >"* null, i32 0, i32 1           ; <i32*> [#uses=1]
>>>>> -       store i32 %57, i32* %59, align 4
>>>>> -       %60 = getelementptr %"struct.SubVector<CDSVector<double, 1, CDS::DefaultAlloc> >"* null, i32 0, i32 2           ; <i32*> [#uses=1]
>>>>> -       store i32 3, i32* %60, align 8
>>>>> +       %57 = getelementptr %"struct.SubVector<CDSVector<double, 1, CDS::DefaultAlloc> >"* null, i32 0, i32 0           ; <%"struct.CDSVector<double,0,CDS::DefaultAlloc>"**> [#uses=1]
>>>>> +       store %"struct.CDSVector<double,0,CDS::DefaultAlloc>"* %velv, %"struct.CDSVector<double,0,CDS::DefaultAlloc>"** %57, align 8
>>>>> +       %58 = getelementptr %"struct.SubVector<CDSVector<double, 1, CDS::DefaultAlloc> >"* null, i32 0, i32 1           ; <i32*> [#uses=1]
>>>>> +       store i32 4, i32* %58, align 4
>>>>> +       %59 = getelementptr %"struct.SubVector<CDSVector<double, 1, CDS::DefaultAlloc> >"* null, i32 0, i32 2           ; <i32*> [#uses=1]
>>>>> +       store i32 3, i32* %59, align 8
>>>>>        unreachable
>>>>> }
>>>>>
>>>>>
>>>>> Modified: llvm/trunk/test/Transforms/ConstantHoisting/X86/phi.ll
>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ConstantHoisting/X86/phi.ll?rev=204389&r1=204388&r2=204389&view=diff
>>>>> ==============================================================================
>>>>> --- llvm/trunk/test/Transforms/ConstantHoisting/X86/phi.ll (original)
>>>>> +++ llvm/trunk/test/Transforms/ConstantHoisting/X86/phi.ll Thu Mar 20 14:55:52 2014
>>>>> @@ -19,11 +19,11 @@ return:
>>>>>   ret i8* %retval.0
>>>>>
>>>>> ; CHECK-LABEL: @test1
>>>>> -; CHECK: entry:
>>>>> -; CHECK: %const_mat = add i64 %const, 1
>>>>> -; CHECK-NEXT: %1 = inttoptr i64 %const_mat to i8*
>>>>> -; CHECK-NEXT: br i1 %cmp
>>>>> -; CHECK: %retval.0 = phi i8* [ null, %entry ], [ %1, %if.end ]
>>>>> +; CHECK: if.end:
>>>>> +; CHECK: %2 = inttoptr i64 %const to i8*
>>>>> +; CHECK-NEXT: br
>>>>> +; CHECK: return:
>>>>> +; CHECK-NEXT: %retval.0 = phi i8* [ null, %entry ], [ %2, %if.end ]
>>>>> }
>>>>>
>>>>> define void @test2(i1 %cmp, i64** %tmp) {
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> llvm-commits mailing list
>>>>> llvm-commits at cs.uiuc.edu
>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>>



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