//===----------------------------------------------------------------------===//
#include "InstCombine.h"
-#include "llvm/IntrinsicInst.h"
-#include "llvm/Target/TargetData.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/Loads.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/Support/CommandLine.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/ADT/Statistic.h"
using namespace llvm;
-STATISTIC(NumDeadStore, "Number of dead stores eliminated");
+/// Hidden option to stress test load slicing, i.e., when this option
+/// is enabled, load slicing bypasses most of its profitability guards.
+/// It will also generate, uncanonalized form of slicing.
+static cl::opt<bool>
+StressLoadSlicing("instcombine-stress-load-slicing", cl::Hidden,
+ cl::desc("Bypass the profitability model of load "
+ "slicing"),
+ cl::init(false));
+
+STATISTIC(NumDeadStore, "Number of dead stores eliminated");
+STATISTIC(NumGlobalCopies, "Number of allocas copied from constant global");
+
+/// pointsToConstantGlobal - Return true if V (possibly indirectly) points to
+/// some part of a constant global variable. This intentionally only accepts
+/// constant expressions because we can't rewrite arbitrary instructions.
+static bool pointsToConstantGlobal(Value *V) {
+ if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
+ return GV->isConstant();
+ if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
+ if (CE->getOpcode() == Instruction::BitCast ||
+ CE->getOpcode() == Instruction::GetElementPtr)
+ return pointsToConstantGlobal(CE->getOperand(0));
+ return false;
+}
+
+/// isOnlyCopiedFromConstantGlobal - Recursively walk the uses of a (derived)
+/// pointer to an alloca. Ignore any reads of the pointer, return false if we
+/// see any stores or other unknown uses. If we see pointer arithmetic, keep
+/// track of whether it moves the pointer (with IsOffset) but otherwise traverse
+/// the uses. If we see a memcpy/memmove that targets an unoffseted pointer to
+/// the alloca, and if the source pointer is a pointer to a constant global, we
+/// can optimize this.
+static bool
+isOnlyCopiedFromConstantGlobal(Value *V, MemTransferInst *&TheCopy,
+ SmallVectorImpl<Instruction *> &ToDelete,
+ bool IsOffset = false) {
+ // We track lifetime intrinsics as we encounter them. If we decide to go
+ // ahead and replace the value with the global, this lets the caller quickly
+ // eliminate the markers.
+
+ for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI!=E; ++UI) {
+ User *U = cast<Instruction>(*UI);
+
+ if (LoadInst *LI = dyn_cast<LoadInst>(U)) {
+ // Ignore non-volatile loads, they are always ok.
+ if (!LI->isSimple()) return false;
+ continue;
+ }
+
+ if (BitCastInst *BCI = dyn_cast<BitCastInst>(U)) {
+ // If uses of the bitcast are ok, we are ok.
+ if (!isOnlyCopiedFromConstantGlobal(BCI, TheCopy, ToDelete, IsOffset))
+ return false;
+ continue;
+ }
+ if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(U)) {
+ // If the GEP has all zero indices, it doesn't offset the pointer. If it
+ // doesn't, it does.
+ if (!isOnlyCopiedFromConstantGlobal(
+ GEP, TheCopy, ToDelete, IsOffset || !GEP->hasAllZeroIndices()))
+ return false;
+ continue;
+ }
+
+ if (CallSite CS = U) {
+ // If this is the function being called then we treat it like a load and
+ // ignore it.
+ if (CS.isCallee(UI))
+ continue;
+
+ // If this is a readonly/readnone call site, then we know it is just a
+ // load (but one that potentially returns the value itself), so we can
+ // ignore it if we know that the value isn't captured.
+ unsigned ArgNo = CS.getArgumentNo(UI);
+ if (CS.onlyReadsMemory() &&
+ (CS.getInstruction()->use_empty() || CS.doesNotCapture(ArgNo)))
+ continue;
+
+ // If this is being passed as a byval argument, the caller is making a
+ // copy, so it is only a read of the alloca.
+ if (CS.isByValArgument(ArgNo))
+ continue;
+ }
+
+ // Lifetime intrinsics can be handled by the caller.
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(U)) {
+ if (II->getIntrinsicID() == Intrinsic::lifetime_start ||
+ II->getIntrinsicID() == Intrinsic::lifetime_end) {
+ assert(II->use_empty() && "Lifetime markers have no result to use!");
+ ToDelete.push_back(II);
+ continue;
+ }
+ }
+
+ // If this is isn't our memcpy/memmove, reject it as something we can't
+ // handle.
+ MemTransferInst *MI = dyn_cast<MemTransferInst>(U);
+ if (MI == 0)
+ return false;
+
+ // If the transfer is using the alloca as a source of the transfer, then
+ // ignore it since it is a load (unless the transfer is volatile).
+ if (UI.getOperandNo() == 1) {
+ if (MI->isVolatile()) return false;
+ continue;
+ }
+
+ // If we already have seen a copy, reject the second one.
+ if (TheCopy) return false;
+
+ // If the pointer has been offset from the start of the alloca, we can't
+ // safely handle this.
+ if (IsOffset) return false;
+
+ // If the memintrinsic isn't using the alloca as the dest, reject it.
+ if (UI.getOperandNo() != 0) return false;
+
+ // If the source of the memcpy/move is not a constant global, reject it.
+ if (!pointsToConstantGlobal(MI->getSource()))
+ return false;
+
+ // Otherwise, the transform is safe. Remember the copy instruction.
+ TheCopy = MI;
+ }
+ return true;
+}
+
+/// isOnlyCopiedFromConstantGlobal - Return true if the specified alloca is only
+/// modified by a copy from a constant global. If we can prove this, we can
+/// replace any uses of the alloca with uses of the global directly.
+static MemTransferInst *
+isOnlyCopiedFromConstantGlobal(AllocaInst *AI,
+ SmallVectorImpl<Instruction *> &ToDelete) {
+ MemTransferInst *TheCopy = 0;
+ if (isOnlyCopiedFromConstantGlobal(AI, TheCopy, ToDelete))
+ return TheCopy;
+ return 0;
+}
Instruction *InstCombiner::visitAllocaInst(AllocaInst &AI) {
+ // Ensure that the alloca array size argument has type intptr_t, so that
+ // any casting is exposed early.
+ if (TD) {
+ Type *IntPtrTy = TD->getIntPtrType(AI.getType());
+ if (AI.getArraySize()->getType() != IntPtrTy) {
+ Value *V = Builder->CreateIntCast(AI.getArraySize(),
+ IntPtrTy, false);
+ AI.setOperand(0, V);
+ return &AI;
+ }
+ }
+
// Convert: alloca Ty, C - where C is a constant != 1 into: alloca [C x Ty], 1
if (AI.isArrayAllocation()) { // Check C != 1
if (const ConstantInt *C = dyn_cast<ConstantInt>(AI.getArraySize())) {
- const Type *NewTy =
+ Type *NewTy =
ArrayType::get(AI.getAllocatedType(), C->getZExtValue());
- assert(isa<AllocaInst>(AI) && "Unknown type of allocation inst!");
AllocaInst *New = Builder->CreateAlloca(NewTy, 0, AI.getName());
New->setAlignment(AI.getAlignment());
// Now that I is pointing to the first non-allocation-inst in the block,
// insert our getelementptr instruction...
//
- Value *NullIdx =Constant::getNullValue(Type::getInt32Ty(AI.getContext()));
- Value *Idx[2];
- Idx[0] = NullIdx;
- Idx[1] = NullIdx;
- Value *V = GetElementPtrInst::CreateInBounds(New, Idx, Idx + 2,
- New->getName()+".sub", It);
+ Type *IdxTy = TD
+ ? TD->getIntPtrType(AI.getType())
+ : Type::getInt64Ty(AI.getContext());
+ Value *NullIdx = Constant::getNullValue(IdxTy);
+ Value *Idx[2] = { NullIdx, NullIdx };
+ Instruction *GEP =
+ GetElementPtrInst::CreateInBounds(New, Idx, New->getName() + ".sub");
+ InsertNewInstBefore(GEP, *It);
// Now make everything use the getelementptr instead of the original
// allocation.
- return ReplaceInstUsesWith(AI, V);
+ return ReplaceInstUsesWith(AI, GEP);
} else if (isa<UndefValue>(AI.getArraySize())) {
return ReplaceInstUsesWith(AI, Constant::getNullValue(AI.getType()));
}
}
- if (TD && isa<AllocaInst>(AI) && AI.getAllocatedType()->isSized()) {
- // If alloca'ing a zero byte object, replace the alloca with a null pointer.
- // Note that we only do this for alloca's, because malloc should allocate
- // and return a unique pointer, even for a zero byte allocation.
- if (TD->getTypeAllocSize(AI.getAllocatedType()) == 0)
- return ReplaceInstUsesWith(AI, Constant::getNullValue(AI.getType()));
-
+ if (TD && AI.getAllocatedType()->isSized()) {
// If the alignment is 0 (unspecified), assign it the preferred alignment.
if (AI.getAlignment() == 0)
AI.setAlignment(TD->getPrefTypeAlignment(AI.getAllocatedType()));
+
+ // Move all alloca's of zero byte objects to the entry block and merge them
+ // together. Note that we only do this for alloca's, because malloc should
+ // allocate and return a unique pointer, even for a zero byte allocation.
+ if (TD->getTypeAllocSize(AI.getAllocatedType()) == 0) {
+ // For a zero sized alloca there is no point in doing an array allocation.
+ // This is helpful if the array size is a complicated expression not used
+ // elsewhere.
+ if (AI.isArrayAllocation()) {
+ AI.setOperand(0, ConstantInt::get(AI.getArraySize()->getType(), 1));
+ return &AI;
+ }
+
+ // Get the first instruction in the entry block.
+ BasicBlock &EntryBlock = AI.getParent()->getParent()->getEntryBlock();
+ Instruction *FirstInst = EntryBlock.getFirstNonPHIOrDbg();
+ if (FirstInst != &AI) {
+ // If the entry block doesn't start with a zero-size alloca then move
+ // this one to the start of the entry block. There is no problem with
+ // dominance as the array size was forced to a constant earlier already.
+ AllocaInst *EntryAI = dyn_cast<AllocaInst>(FirstInst);
+ if (!EntryAI || !EntryAI->getAllocatedType()->isSized() ||
+ TD->getTypeAllocSize(EntryAI->getAllocatedType()) != 0) {
+ AI.moveBefore(FirstInst);
+ return &AI;
+ }
+
+ // If the alignment of the entry block alloca is 0 (unspecified),
+ // assign it the preferred alignment.
+ if (EntryAI->getAlignment() == 0)
+ EntryAI->setAlignment(
+ TD->getPrefTypeAlignment(EntryAI->getAllocatedType()));
+ // Replace this zero-sized alloca with the one at the start of the entry
+ // block after ensuring that the address will be aligned enough for both
+ // types.
+ unsigned MaxAlign = std::max(EntryAI->getAlignment(),
+ AI.getAlignment());
+ EntryAI->setAlignment(MaxAlign);
+ if (AI.getType() != EntryAI->getType())
+ return new BitCastInst(EntryAI, AI.getType());
+ return ReplaceInstUsesWith(AI, EntryAI);
+ }
+ }
}
- return 0;
+ if (AI.getAlignment()) {
+ // Check to see if this allocation is only modified by a memcpy/memmove from
+ // a constant global whose alignment is equal to or exceeds that of the
+ // allocation. If this is the case, we can change all users to use
+ // the constant global instead. This is commonly produced by the CFE by
+ // constructs like "void foo() { int A[] = {1,2,3,4,5,6,7,8,9...}; }" if 'A'
+ // is only subsequently read.
+ SmallVector<Instruction *, 4> ToDelete;
+ if (MemTransferInst *Copy = isOnlyCopiedFromConstantGlobal(&AI, ToDelete)) {
+ unsigned SourceAlign = getOrEnforceKnownAlignment(Copy->getSource(),
+ AI.getAlignment(), TD);
+ if (AI.getAlignment() <= SourceAlign) {
+ DEBUG(dbgs() << "Found alloca equal to global: " << AI << '\n');
+ DEBUG(dbgs() << " memcpy = " << *Copy << '\n');
+ for (unsigned i = 0, e = ToDelete.size(); i != e; ++i)
+ EraseInstFromFunction(*ToDelete[i]);
+ Constant *TheSrc = cast<Constant>(Copy->getSource());
+ Instruction *NewI
+ = ReplaceInstUsesWith(AI, ConstantExpr::getBitCast(TheSrc,
+ AI.getType()));
+ EraseInstFromFunction(*Copy);
+ ++NumGlobalCopies;
+ return NewI;
+ }
+ }
+ }
+
+ // At last, use the generic allocation site handler to aggressively remove
+ // unused allocas.
+ return visitAllocSite(AI);
}
/// InstCombineLoadCast - Fold 'load (cast P)' -> cast (load P)' when possible.
static Instruction *InstCombineLoadCast(InstCombiner &IC, LoadInst &LI,
- const TargetData *TD) {
+ const DataLayout *TD) {
User *CI = cast<User>(LI.getOperand(0));
Value *CastOp = CI->getOperand(0);
-
const PointerType *DestTy = cast<PointerType>(CI->getType());
- const Type *DestPTy = DestTy->getElementType();
- if (
const PointerType *SrcTy = dyn_cast<PointerType>(CastOp->getType())) {
+ PointerType *DestTy = cast<PointerType>(CI->getType());
+ Type *DestPTy = DestTy->getElementType();
+ if (PointerType *SrcTy = dyn_cast<PointerType>(CastOp->getType())) {
// If the address spaces don't match, don't eliminate the cast.
if (DestTy->getAddressSpace() != SrcTy->getAddressSpace())
return 0;
- const Type *SrcPTy = SrcTy->getElementType();
+ Type *SrcPTy = SrcTy->getElementType();
- if (DestPTy->isInteger() || isa<PointerType>(DestPTy) ||
- isa<VectorType>(DestPTy)) {
+ if (DestPTy->isIntegerTy() || DestPTy->isPointerTy() ||
+ DestPTy->isVectorTy()) {
// If the source is an array, the code below will not succeed. Check to
// see if a trivial 'gep P, 0, 0' will help matters. Only do this for
// constants.
- if (
const ArrayType *ASrcTy = dyn_cast<ArrayType>(SrcPTy))
+ if (ArrayType *ASrcTy = dyn_cast<ArrayType>(SrcPTy))
if (Constant *CSrc = dyn_cast<Constant>(CastOp))
if (ASrcTy->getNumElements() != 0) {
- Value *Idxs[2];
- Idxs[0] = Constant::getNullValue(Type::getInt32Ty(LI.getContext()));
- Idxs[1] = Idxs[0];
- CastOp = ConstantExpr::getGetElementPtr(CSrc, Idxs, 2);
+ Type *IdxTy = TD
+ ? TD->getIntPtrType(SrcTy)
+ : Type::getInt64Ty(SrcTy->getContext());
+ Value *Idx = Constant::getNullValue(IdxTy);
+ Value *Idxs[2] = { Idx, Idx };
+ CastOp = ConstantExpr::getGetElementPtr(CSrc, Idxs);
SrcTy = cast<PointerType>(CastOp->getType());
SrcPTy = SrcTy->getElementType();
}
- if (IC.getTargetData() &&
- (SrcPTy->isInteger() || isa<PointerType>(SrcPTy) ||
- isa<VectorType>(SrcPTy)) &&
+ if (IC.getDataLayout() &&
+ (SrcPTy->isIntegerTy() || SrcPTy->isPointerTy() ||
+ SrcPTy->isVectorTy()) &&
// Do not allow turning this into a load of an integer, which is then
// casted to a pointer, this pessimizes pointer analysis a lot.
- (isa<PointerType>(SrcPTy) == isa<PointerType>(LI.getType())) &&
- IC.getTargetData()->getTypeSizeInBits(SrcPTy) ==
- IC.getTargetData()->getTypeSizeInBits(DestPTy)) {
+ (SrcPTy->isPointerTy() == LI.getType()->isPointerTy()) &&
+ IC.getDataLayout()->getTypeSizeInBits(SrcPTy) ==
+ IC.getDataLayout()->getTypeSizeInBits(DestPTy)) {
// Okay, we are casting from one integer or pointer type to another of
// the same size. Instead of casting the pointer before the load, cast
// the result of the loaded value.
- Value *NewLoad =
+ LoadInst *NewLoad =
IC.Builder->CreateLoad(CastOp, LI.isVolatile(), CI->getName());
- cast<LoadInst>(NewLoad)->setAlignment(LI.getAlignment());
+ NewLoad->setAlignment(LI.getAlignment());
+ NewLoad->setAtomic(LI.getOrdering(), LI.getSynchScope());
// Now cast the result of the load.
return new BitCastInst(NewLoad, LI.getType());
}
return 0;
}
+namespace {
+ /// \brief Helper structure used to slice a load in smaller loads.
+ struct LoadedSlice {
+ // The last instruction that represent the slice. This should be a
+ // truncate instruction.
+ Instruction *Inst;
+ // The original load instruction.
+ LoadInst *Origin;
+ // The right shift amount in bits from the original load.
+ unsigned Shift;
+
+ LoadedSlice(Instruction *Inst = NULL, LoadInst *Origin = NULL,
+ unsigned Shift = 0)
+ : Inst(Inst), Origin(Origin), Shift(Shift) {}
+
+ LoadedSlice(const LoadedSlice& LS) : Inst(LS.Inst), Origin(LS.Origin),
+ Shift(LS.Shift) {}
+
+ /// \brief Get the bits used in a chunk of bits \p BitWidth large.
+ /// \return Result is \p BitWidth and has used bits set to 1 and
+ /// not used bits set to 0.
+ APInt getUsedBits() const {
+ // Reproduce the trunc(lshr) sequence:
+ // - Start from the truncated value.
+ // - Zero extend to the desired bit width.
+ // - Shift left.
+ assert(Origin && "No original load to compare against.");
+ unsigned BitWidth = Origin->getType()->getPrimitiveSizeInBits();
+ assert(Inst && "This slice is not bound to an instruction");
+ assert(Inst->getType()->getPrimitiveSizeInBits() <= BitWidth &&
+ "Extracted slice is smaller than the whole type!");
+ APInt UsedBits(Inst->getType()->getPrimitiveSizeInBits(), 0);
+ UsedBits.setAllBits();
+ UsedBits = UsedBits.zext(BitWidth);
+ UsedBits <<= Shift;
+ return UsedBits;
+ }
+
+ /// \brief Get the size of the slice to be loaded in bytes.
+ unsigned getLoadedSize() const {
+ unsigned SliceSize = getUsedBits().countPopulation();
+ assert(!(SliceSize & 0x7) && "Size is not a multiple of a byte.");
+ return SliceSize / 8;
+ }
+
+ /// \brief Get the offset in bytes of this slice in the original chunk of
+ /// bits, whose layout is defined by \p IsBigEndian.
+ uint64_t getOffsetFromBase(bool IsBigEndian) const {
+ assert(!(Shift & 0x7) && "Shifts not aligned on Bytes are not support.");
+ uint64_t Offset = Shift / 8;
+ unsigned TySizeInBytes = Origin->getType()->getPrimitiveSizeInBits() / 8;
+ assert(!(Origin->getType()->getPrimitiveSizeInBits() & 0x7) &&
+ "The size of the original loaded type is not a multiple of a"
+ " byte.");
+ // If Offset is bigger than TySizeInBytes, it means we are loading all
+ // zeros. This should have been optimized before in the process.
+ assert(TySizeInBytes > Offset &&
+ "Invalid shift amount for given loaded size");
+ if (IsBigEndian)
+ Offset = TySizeInBytes - Offset - getLoadedSize();
+ return Offset;
+ }
+
+ /// \brief Generate the sequence of instructions to load the slice
+ /// represented by this object and redirect the uses of this slice to
+ /// this new sequence of instructions.
+ /// \pre this->Inst && this->Origin are valid Instructions.
+ /// \return The last instruction of the sequence used to load the slice.
+ Instruction *loadSlice(InstCombiner::BuilderTy &Builder,
+ bool IsBigEndian) const {
+ assert(Inst && Origin && "Unable to replace a non-existing slice.");
+ Value *BaseAddr = Origin->getOperand(0);
+ unsigned Alignment = Origin->getAlignment();
+ Builder.SetInsertPoint(Origin);
+ // Assume we are looking at a chunk of bytes.
+ // BaseAddr = (i8*)BaseAddr.
+ BaseAddr = Builder.CreateBitCast(BaseAddr, Builder.getInt8PtrTy(),
+ "raw_cast");
+ // Get the offset in that chunk of bytes w.r.t. the endianess.
+ uint64_t Offset = getOffsetFromBase(IsBigEndian);
+ if (Offset) {
+ APInt APOffset(64, Offset);
+ // BaseAddr = BaseAddr + Offset.
+ BaseAddr = Builder.CreateInBoundsGEP(BaseAddr, Builder.getInt(APOffset),
+ "raw_idx");
+ }
+
+ // Create the type of the loaded slice according to its size.
+ Type *SliceType =
+ Type::getIntNTy(Origin->getContext(), getLoadedSize() * 8);
+
+ // Bit cast the raw pointer to the pointer type of the slice.
+ BaseAddr = Builder.CreateBitCast(BaseAddr, SliceType->getPointerTo(),
+ "cast");
+
+ // Compute the new alignment.
+ if (Offset != 0)
+ Alignment = MinAlign(Alignment, Alignment + Offset);
+
+ // Create the load for the slice.
+ Instruction *LastInst = Builder.CreateAlignedLoad(BaseAddr, Alignment,
+ Inst->getName()+".val");
+ // If the final type is not the same as the loaded type, this means that
+ // we have to pad with zero. Create a zero extend for that.
+ Type * FinalType = Inst->getType();
+ if (SliceType != FinalType)
+ LastInst = cast<Instruction>(Builder.CreateZExt(LastInst, FinalType));
+
+ // Update the IR to reflect the new access to the slice.
+ Inst->replaceAllUsesWith(LastInst);
+
+ return LastInst;
+ }
+
+ /// \brief Check if it would be profitable to expand this slice as an
+ /// independant load.
+ bool isProfitable() const {
+ // Slicing is assumed to be profitable iff the chains leads to arithmetic
+ // operations.
+ SmallVector<const Instruction *, 8> Uses;
+ Uses.push_back(Inst);
+ do {
+ const Instruction *Use = Uses.pop_back_val();
+ for (Value::const_use_iterator UseIt = Use->use_begin(),
+ UseItEnd = Use->use_end(); UseIt != UseItEnd; ++UseIt) {
+ const Instruction *UseOfUse = cast<Instruction>(*UseIt);
+ // Consider these instructions as arithmetic operations.
+ if (isa<BinaryOperator>(UseOfUse) ||
+ isa<CastInst>(UseOfUse) ||
+ isa<PHINode>(UseOfUse) ||
+ isa<GetElementPtrInst>(UseOfUse))
+ return true;
+ // No need to check if the Use has already been checked as we do not
+ // insert any PHINode.
+ Uses.push_back(UseOfUse);
+ }
+ } while (!Uses.empty());
+ DEBUG(dbgs() << "IC: Not a profitable slice " << *Inst << '\n');
+ return false;
+ }
+ };
+}
+
+/// \brief Check the profitability of all involved LoadedSlice.
+/// Unless StressLoadSlicing is specified, this also returns false
+/// when slicing is not in the canonical form.
+/// The canonical form of sliced load is (1) two loads,
+/// which are (2) next to each other in memory.
+///
+/// FIXME: We may want to allow more slices to be created but
+/// this means other passes should know how to deal with all those
+/// slices.
+/// FIXME: We may want to split loads to different types, e.g.,
+/// int vs. float.
+static bool
+isSlicingProfitable(const SmallVectorImpl<LoadedSlice> &LoadedSlices,
+ const APInt &UsedBits) {
+ unsigned NbOfSlices = LoadedSlices.size();
+ // Check (1).
+ if (!StressLoadSlicing && NbOfSlices != 2)
+ return false;
+
+ // Check (2).
+ if (!StressLoadSlicing && !UsedBits.isAllOnesValue()) {
+ // Get rid of the unused bits on the right.
+ APInt MemoryLayout = UsedBits.lshr(UsedBits.countTrailingZeros());
+ // Get rid of the unused bits on the left.
+ if (MemoryLayout.countLeadingZeros())
+ MemoryLayout = MemoryLayout.trunc(MemoryLayout.getActiveBits());
+ // Check that the chunk of memory is completely used.
+ if (!MemoryLayout.isAllOnesValue())
+ return false;
+ }
+
+ unsigned NbOfProfitableSlices = 0;
+ for (unsigned CurrSlice = 0; CurrSlice < NbOfSlices; ++CurrSlice) {
+ if (LoadedSlices[CurrSlice].isProfitable())
+ ++NbOfProfitableSlices;
+ else if (!StressLoadSlicing)
+ return false;
+ }
+ // In Stress mode, we may have 0 profitable slice.
+ // Check that here.
+ // In non-Stress mode, all the slices are profitable at this point.
+ return NbOfProfitableSlices > 0;
+}
+
+/// \brief If the given load, \p LI, is used only by trunc or trunc(lshr)
+/// operations, split it in the various pieces being extracted.
+///
+/// This sort of thing is introduced by SROA.
+/// This slicing takes care not to insert overlapping loads.
+/// \pre LI is a simple load (i.e., not an atomic or volatile load).
+static Instruction *sliceUpLoadInst(LoadInst &LI,
+ InstCombiner::BuilderTy &Builder,
+ DataLayout &TD) {
+ assert(LI.isSimple() && "We are trying to transform a non-simple load!");
+
+ // FIXME: If we want to support floating point and vector types, we should
+ // support bitcast and extract/insert element instructions.
+ Type *LITy = LI.getType();
+ if (!LITy->isIntegerTy()) return 0;
+
+ // Keep track of already used bits to detect overlapping values.
+ // In that case, we will just abort the transformation.
+ APInt UsedBits(LITy->getPrimitiveSizeInBits(), 0);
+
+ SmallVector<LoadedSlice, 4> LoadedSlices;
+
+ // Check if this load is used as several smaller chunks of bits.
+ // Basically, look for uses in trunc or trunc(lshr) and record a new chain
+ // of computation for each trunc.
+ for (Value::use_iterator UI = LI.use_begin(), UIEnd = LI.use_end();
+ UI != UIEnd; ++UI) {
+ Instruction *User = cast<Instruction>(*UI);
+ unsigned Shift = 0;
+
+ // Check if this is a trunc(lshr).
+ if (User->getOpcode() == Instruction::LShr && User->hasOneUse() &&
+ isa<ConstantInt>(User->getOperand(1))) {
+ Shift = cast<ConstantInt>(User->getOperand(1))->getZExtValue();
+ User = User->use_back();
+ }
+
+ // At this point, User is a TruncInst, iff we encountered, trunc or
+ // trunc(lshr).
+ if (!isa<TruncInst>(User))
+ return 0;
+
+ // The width of the type must be a power of 2 and greater than 8-bits.
+ // Otherwise the load cannot be represented in LLVM IR.
+ // Moreover, if we shifted with a non 8-bits multiple, the slice
+ // will be accross several bytes. We do not support that.
+ unsigned Width = User->getType()->getPrimitiveSizeInBits();
+ if (Width < 8 || !isPowerOf2_32(Width) || (Shift & 0x7))
+ return 0;
+
+ // Build the slice for this chain of computations.
+ LoadedSlice LS(User, &LI, Shift);
+ APInt CurrentUsedBits = LS.getUsedBits();
+
+ // Check if this slice overlaps with another.
+ if ((CurrentUsedBits & UsedBits) != 0)
+ return 0;
+ // Update the bits used globally.
+ UsedBits |= CurrentUsedBits;
+
+ // Record the slice.
+ LoadedSlices.push_back(LS);
+ }
+
+ // Abort slicing if it does not seem to be profitable.
+ if (!isSlicingProfitable(LoadedSlices, UsedBits))
+ return 0;
+
+ // Rewrite each chain to use an independent load.
+ // By construction, each chain can be represented by a unique load.
+ bool IsBigEndian = TD.isBigEndian();
+ for (SmallVectorImpl<LoadedSlice>::const_iterator LSIt = LoadedSlices.begin(),
+ LSItEnd = LoadedSlices.end(); LSIt != LSItEnd; ++LSIt) {
+ Instruction *SliceInst = LSIt->loadSlice(Builder, IsBigEndian);
+ (void)SliceInst;
+ DEBUG(dbgs() << "IC: Replacing " << *LSIt->Inst << "\n"
+ " with " << *SliceInst << '\n');
+ }
+ return 0; // Don't do anything with LI.
+}
+
Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
Value *Op = LI.getOperand(0);
// Attempt to improve the alignment.
if (TD) {
unsigned KnownAlign =
- GetOrEnforceKnownAlignment(Op, TD->getPrefTypeAlignment(LI.getType()));
- if (KnownAlign >
- (LI.getAlignment() == 0 ? TD->getABITypeAlignment(LI.getType()) :
- LI.getAlignment()))
+ getOrEnforceKnownAlignment(Op, TD->getPrefTypeAlignment(LI.getType()),TD);
+ unsigned LoadAlign = LI.getAlignment();
+ unsigned EffectiveLoadAlign = LoadAlign != 0 ? LoadAlign :
+ TD->getABITypeAlignment(LI.getType());
+
+ if (KnownAlign > EffectiveLoadAlign)
LI.setAlignment(KnownAlign);
+ else if (LoadAlign == 0)
+ LI.setAlignment(EffectiveLoadAlign);
}
// load (cast X) --> cast (load X) iff safe.
if (Instruction *Res = InstCombineLoadCast(*this, LI, TD))
return Res;
- // None of the following transforms are legal for volatile loads.
- if (LI.isVolatile()) return 0;
-
+ // None of the following transforms are legal for volatile/atomic loads.
+ // FIXME: Some of it is okay for atomic loads; needs refactoring.
+ if (!LI.isSimple()) return 0;
+
// Do really simple store-to-load forwarding and load CSE, to catch cases
- // where there are several consequtive memory accesses to the same location,
+ // where there are several consecutive memory accesses to the same location,
// separated by a few arithmetic operations.
BasicBlock::iterator BBI = &LI;
if (Value *AvailableVal = FindAvailableLoadedValue(Op, LI.getParent(), BBI,6))
Constant::getNullValue(Op->getType()), &LI);
return ReplaceInstUsesWith(LI, UndefValue::get(LI.getType()));
}
- }
+ }
// load null/undef -> unreachable
// TODO: Consider a target hook for valid address spaces for this xform.
if (CE->isCast())
if (Instruction *Res = InstCombineLoadCast(*this, LI, TD))
return Res;
-
+
if (Op->hasOneUse()) {
// Change select and PHI nodes to select values instead of addresses: this
// helps alias analysis out a lot, allows many others simplifications, and
//
if (SelectInst *SI = dyn_cast<SelectInst>(Op)) {
// load (select (Cond, &V1, &V2)) --> select(Cond, load &V1, load &V2).
- if (isSafeToLoadUnconditionally(SI->getOperand(1), SI, TD) &&
- isSafeToLoadUnconditionally(SI->getOperand(2), SI, TD)) {
- Value *V1 = Builder->CreateLoad(SI->getOperand(1),
- SI->getOperand(1)->getName()+".val");
- Value *V2 = Builder->CreateLoad(SI->getOperand(2),
- SI->getOperand(2)->getName()+".val");
- cast<LoadInst>(V1)->setAlignment(LI.getAlignment());
- cast<LoadInst>(V2)->setAlignment(LI.getAlignment());
+ unsigned Align = LI.getAlignment();
+ if (isSafeToLoadUnconditionally(SI->getOperand(1), SI, Align, TD) &&
+ isSafeToLoadUnconditionally(SI->getOperand(2), SI, Align, TD)) {
+ LoadInst *V1 = Builder->CreateLoad(SI->getOperand(1),
+ SI->getOperand(1)->getName()+".val");
+ LoadInst *V2 = Builder->CreateLoad(SI->getOperand(2),
+ SI->getOperand(2)->getName()+".val");
+ V1->setAlignment(Align);
+ V2->setAlignment(Align);
return SelectInst::Create(SI->getCondition(), V1, V2);
}
}
}
}
+
+ // Try to split a load in smaller non-overlapping loads to expose independant
+ // chain of computations and get rid of trunc/lshr sequence of code.
+ // The data layout is required for that operation, as code generation will
+ // change with respect to endianess.
+ if (TD)
+ return sliceUpLoadInst(LI, *Builder, *TD);
return 0;
}
User *CI = cast<User>(SI.getOperand(1));
Value *CastOp = CI->getOperand(0);
-
const Type *DestPTy = cast<PointerType>(CI->getType())->getElementType();
-
const PointerType *SrcTy = dyn_cast<PointerType>(CastOp->getType());
+ Type *DestPTy = cast<PointerType>(CI->getType())->getElementType();
+ PointerType *SrcTy = dyn_cast<PointerType>(CastOp->getType());
if (SrcTy == 0) return 0;
-
- const Type *SrcPTy = SrcTy->getElementType();
- if (!DestPTy->isInteger() && !isa<PointerType>(DestPTy))
+ Type *SrcPTy = SrcTy->getElementType();
+
+ if (!DestPTy->isIntegerTy() && !DestPTy->isPointerTy())
return 0;
-
+
/// NewGEPIndices - If SrcPTy is an aggregate type, we can emit a "noop gep"
/// to its first element. This allows us to handle things like:
/// store i32 xxx, (bitcast {foo*, float}* %P to i32*)
/// on 32-bit hosts.
SmallVector<Value*, 4> NewGEPIndices;
-
+
// If the source is an array, the code below will not succeed. Check to
// see if a trivial 'gep P, 0, 0' will help matters. Only do this for
// constants.
- if (isa<ArrayType>(SrcPTy) || isa<StructType>(SrcPTy)) {
+ if (SrcPTy->isArrayTy() || SrcPTy->isStructTy()) {
// Index through pointer.
Constant *Zero = Constant::getNullValue(Type::getInt32Ty(SI.getContext()));
NewGEPIndices.push_back(Zero);
-
+
while (1) {
- if (const StructType *STy = dyn_cast<StructType>(SrcPTy)) {
+ if (StructType *STy = dyn_cast<StructType>(SrcPTy)) {
if (!STy->getNumElements()) /* Struct can be empty {} */
break;
NewGEPIndices.push_back(Zero);
SrcPTy = STy->getElementType(0);
- } else if (
const ArrayType *ATy = dyn_cast<ArrayType>(SrcPTy)) {
+ } else if (ArrayType *ATy = dyn_cast<ArrayType>(SrcPTy)) {
NewGEPIndices.push_back(Zero);
SrcPTy = ATy->getElementType();
} else {
break;
}
}
-
+
SrcTy = PointerType::get(SrcPTy, SrcTy->getAddressSpace());
}
- if (!SrcPTy->isInteger() && !isa<PointerType>(SrcPTy))
+ if (!SrcPTy->isIntegerTy() && !SrcPTy->isPointerTy())
return 0;
-
+
// If the pointers point into different address spaces or if they point to
// values with different sizes, we can't do the transformation.
- if (!IC.getTargetData() ||
- SrcTy->getAddressSpace() !=
+ if (!IC.getDataLayout() ||
+ SrcTy->getAddressSpace() !=
cast<PointerType>(CI->getType())->getAddressSpace() ||
- IC.getTargetData()->getTypeSizeInBits(SrcPTy) !=
- IC.getTargetData()->getTypeSizeInBits(DestPTy))
+ IC.getDataLayout()->getTypeSizeInBits(SrcPTy) !=
+ IC.getDataLayout()->getTypeSizeInBits(DestPTy))
return 0;
// Okay, we are casting from one integer or pointer type to another of
- // the same size. Instead of casting the pointer before
+ // the same size. Instead of casting the pointer before
// the store, cast the value to be stored.
Value *NewCast;
Value *SIOp0 = SI.getOperand(0);
Instruction::CastOps opcode = Instruction::BitCast;
- const Type* CastSrcTy = SIOp0->getType();
- const Type* CastDstTy = SrcPTy;
- if (isa<PointerType>(CastDstTy)) {
- if (CastSrcTy->isInteger())
+ Type* CastSrcTy = SIOp0->getType();
+ Type* CastDstTy = SrcPTy;
+ if (CastDstTy->isPointerTy()) {
+ if (CastSrcTy->isIntegerTy())
opcode = Instruction::IntToPtr;
- } else if (isa<IntegerType>(CastDstTy)) {
- if (isa<PointerType>(SIOp0->getType()))
+ } else if (CastDstTy->isIntegerTy()) {
+ if (SIOp0->getType()->isPointerTy())
opcode = Instruction::PtrToInt;
}
-
+
// SIOp0 is a pointer to aggregate and this is a store to the first field,
// emit a GEP to index into its first field.
if (!NewGEPIndices.empty())
- CastOp = IC.Builder->CreateInBoundsGEP(CastOp, NewGEPIndices.begin(),
- NewGEPIndices.end());
-
+ CastOp = IC.Builder->CreateInBoundsGEP(CastOp, NewGEPIndices);
+
NewCast = IC.Builder->CreateCast(opcode, SIOp0, CastDstTy,
SIOp0->getName()+".c");
- return new StoreInst(NewCast, CastOp);
+ SI.setOperand(0, NewCast);
+ SI.setOperand(1, CastOp);
+ return &SI;
}
/// equivalentAddressValues - Test if A and B will obviously have the same
static bool equivalentAddressValues(Value *A, Value *B) {
// Test if the values are trivially equivalent.
if (A == B) return true;
-
+
// Test if the values come form identical arithmetic instructions.
// This uses isIdenticalToWhenDefined instead of isIdenticalTo because
// its only used to compare two uses within the same basic block, which
if (Instruction *BI = dyn_cast<Instruction>(B))
if (cast<Instruction>(A)->isIdenticalToWhenDefined(BI))
return true;
-
+
// Otherwise they may not be equivalent.
return false;
}
-// If this instruction has two uses, one of which is a llvm.dbg.declare,
-// return the llvm.dbg.declare.
-DbgDeclareInst *InstCombiner::hasOneUsePlusDeclare(Value *V) {
- if (!V->hasNUses(2))
- return 0;
- for (Value::use_iterator UI = V->use_begin(), E = V->use_end();
- UI != E; ++UI) {
- if (DbgDeclareInst *DI = dyn_cast<DbgDeclareInst>(UI))
- return DI;
- if (isa<BitCastInst>(UI) && UI->hasOneUse()) {
- if (DbgDeclareInst *DI = dyn_cast<DbgDeclareInst>(UI->use_begin()))
- return DI;
- }
- }
- return 0;
-}
-
Instruction *InstCombiner::visitStoreInst(StoreInst &SI) {
Value *Val = SI.getOperand(0);
Value *Ptr = SI.getOperand(1);
- // If the RHS is an alloca with a single use, zapify the store, making the
- // alloca dead.
- // If the RHS is an alloca with a two uses, the other one being a
- // llvm.dbg.declare, zapify the store and the declare, making the
- // alloca dead. We must do this to prevent declares from affecting
- // codegen.
- if (!SI.isVolatile()) {
- if (Ptr->hasOneUse()) {
- if (isa<AllocaInst>(Ptr))
- return EraseInstFromFunction(SI);
- if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Ptr)) {
- if (isa<AllocaInst>(GEP->getOperand(0))) {
- if (GEP->getOperand(0)->hasOneUse())
- return EraseInstFromFunction(SI);
- if (DbgDeclareInst *DI = hasOneUsePlusDeclare(GEP->getOperand(0))) {
- EraseInstFromFunction(*DI);
- return EraseInstFromFunction(SI);
- }
- }
- }
- }
- if (DbgDeclareInst *DI = hasOneUsePlusDeclare(Ptr)) {
- EraseInstFromFunction(*DI);
- return EraseInstFromFunction(SI);
- }
- }
-
// Attempt to improve the alignment.
if (TD) {
unsigned KnownAlign =
- GetOrEnforceKnownAlignment(Ptr, TD->getPrefTypeAlignment(Val->getType()));
- if (KnownAlign >
- (SI.getAlignment() == 0 ? TD->getABITypeAlignment(Val->getType()) :
- SI.getAlignment()))
+ getOrEnforceKnownAlignment(Ptr, TD->getPrefTypeAlignment(Val->getType()),
+ TD);
+ unsigned StoreAlign = SI.getAlignment();
+ unsigned EffectiveStoreAlign = StoreAlign != 0 ? StoreAlign :
+ TD->getABITypeAlignment(Val->getType());
+
+ if (KnownAlign > EffectiveStoreAlign)
SI.setAlignment(KnownAlign);
+ else if (StoreAlign == 0)
+ SI.setAlignment(EffectiveStoreAlign);
+ }
+
+ // Don't hack volatile/atomic stores.
+ // FIXME: Some bits are legal for atomic stores; needs refactoring.
+ if (!SI.isSimple()) return 0;
+
+ // If the RHS is an alloca with a single use, zapify the store, making the
+ // alloca dead.
+ if (Ptr->hasOneUse()) {
+ if (isa<AllocaInst>(Ptr))
+ return EraseInstFromFunction(SI);
+ if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Ptr)) {
+ if (isa<AllocaInst>(GEP->getOperand(0))) {
+ if (GEP->getOperand(0)->hasOneUse())
+ return EraseInstFromFunction(SI);
+ }
+ }
}
// Do really simple DSE, to catch cases where there are several consecutive
// Don't count debug info directives, lest they affect codegen,
// and we skip pointer-to-pointer bitcasts, which are NOPs.
if (isa<DbgInfoIntrinsic>(BBI) ||
- (isa<BitCastInst>(BBI) && isa<PointerType>(BBI->getType()))) {
+ (isa<BitCastInst>(BBI) && BBI->getType()->isPointerTy())) {
ScanInsts++;
continue;
- }
-
+ }
+
if (StoreInst *PrevSI = dyn_cast<StoreInst>(BBI)) {
// Prev store isn't volatile, and stores to the same location?
- if (!PrevSI->isVolatile() &&equivalentAddressValues(PrevSI->getOperand(1),
- SI.getOperand(1))) {
+ if (PrevSI->isSimple() && equivalentAddressValues(PrevSI->getOperand(1),
+ SI.getOperand(1))) {
++NumDeadStore;
++BBI;
EraseInstFromFunction(*PrevSI);
}
break;
}
-
+
// If this is a load, we have to stop. However, if the loaded value is from
// the pointer we're loading and is producing the pointer we're storing,
// then *this* store is dead (X = load P; store X -> P).
if (LoadInst *LI = dyn_cast<LoadInst>(BBI)) {
if (LI == Val && equivalentAddressValues(LI->getOperand(0), Ptr) &&
- !SI.isVolatile())
+ LI->isSimple())
return EraseInstFromFunction(SI);
-
+
// Otherwise, this is a load from some other location. Stores before it
// may not be dead.
break;
}
-
+
// Don't skip over loads or things that can modify memory.
if (BBI->mayWriteToMemory() || BBI->mayReadFromMemory())
break;
}
-
-
- if (SI.isVolatile()) return 0; // Don't hack volatile stores.
// store X, null -> turns into 'unreachable' in SimplifyCFG
if (isa<ConstantPointerNull>(Ptr) && SI.getPointerAddressSpace() == 0) {
if (Instruction *Res = InstCombineStoreToCast(*this, SI))
return Res;
-
+
// If this store is the last instruction in the basic block (possibly
// excepting debug info instructions), and if the block ends with an
// unconditional branch, try to move it to the successor block.
- BBI = &SI;
+ BBI = &SI;
do {
++BBI;
} while (isa<DbgInfoIntrinsic>(BBI) ||
- (isa<BitCastInst>(BBI) && isa<PointerType>(BBI->getType())));
+ (isa<BitCastInst>(BBI) && BBI->getType()->isPointerTy()));
if (BranchInst *BI = dyn_cast<BranchInst>(BBI))
if (BI->isUnconditional())
if (SimplifyStoreAtEndOfBlock(SI))
return 0; // xform done!
-
+
return 0;
}
///
bool InstCombiner::SimplifyStoreAtEndOfBlock(StoreInst &SI) {
BasicBlock *StoreBB = SI.getParent();
-
+
// Check to see if the successor block has exactly two incoming edges. If
// so, see if the other predecessor contains a store to the same location.
// if so, insert a PHI node (if needed) and move the stores down.
BasicBlock *DestBB = StoreBB->getTerminator()->getSuccessor(0);
-
+
// Determine whether Dest has exactly two predecessors and, if so, compute
// the other predecessor.
pred_iterator PI = pred_begin(DestBB);
+ BasicBlock *P = *PI;
BasicBlock *OtherBB = 0;
- if (*PI != StoreBB)
- OtherBB = *PI;
- ++PI;
- if (PI == pred_end(DestBB))
+
+ if (P != StoreBB)
+ OtherBB = P;
+
+ if (++PI == pred_end(DestBB))
return false;
-
- if (*PI != StoreBB) {
+
+ P = *PI;
+ if (P != StoreBB) {
if (OtherBB)
return false;
- OtherBB = *PI;
+ OtherBB = P;
}
if (++PI != pred_end(DestBB))
return false;
BranchInst *OtherBr = dyn_cast<BranchInst>(BBI);
if (!OtherBr || BBI == OtherBB->begin())
return false;
-
+
// If the other block ends in an unconditional branch, check for the 'if then
// else' case. there is an instruction before the branch.
StoreInst *OtherStore = 0;
--BBI;
// Skip over debugging info.
while (isa<DbgInfoIntrinsic>(BBI) ||
- (isa<BitCastInst>(BBI) && isa<PointerType>(BBI->getType()))) {
+ (isa<BitCastInst>(BBI) && BBI->getType()->isPointerTy())) {
if (BBI==OtherBB->begin())
return false;
--BBI;
}
- // If this isn't a store, isn't a store to the same location, or if the
- // alignments differ, bail out.
+ // If this isn't a store, isn't a store to the same location, or is not the
+ // right kind of store, bail out.
OtherStore = dyn_cast<StoreInst>(BBI);
if (!OtherStore || OtherStore->getOperand(1) != SI.getOperand(1) ||
- OtherStore->getAlignment() != SI.getAlignment())
+ !SI.isSameOperationAs(OtherStore))
return false;
} else {
// Otherwise, the other block ended with a conditional branch. If one of the
// destinations is StoreBB, then we have the if/then case.
- if (OtherBr->getSuccessor(0) != StoreBB &&
+ if (OtherBr->getSuccessor(0) != StoreBB &&
OtherBr->getSuccessor(1) != StoreBB)
return false;
-
+
// Okay, we know that OtherBr now goes to Dest and StoreBB, so this is an
// if/then triangle. See if there is a store to the same ptr as SI that
// lives in OtherBB.
// Check to see if we find the matching store.
if ((OtherStore = dyn_cast<StoreInst>(BBI))) {
if (OtherStore->getOperand(1) != SI.getOperand(1) ||
- OtherStore->getAlignment() != SI.getAlignment())
+ !SI.isSameOperationAs(OtherStore))
return false;
break;
}
BBI == OtherBB->begin())
return false;
}
-
+
// In order to eliminate the store in OtherBr, we have to
// make sure nothing reads or overwrites the stored value in
// StoreBB.
return false;
}
}
-
+
// Insert a PHI node now if we need it.
Value *MergedVal = OtherStore->getOperand(0);
if (MergedVal != SI.getOperand(0)) {
- PHINode *PN = PHINode::Create(MergedVal->getType(), "storemerge");
- PN->reserveOperandSpace(2);
+ PHINode *PN = PHINode::Create(MergedVal->getType(), 2, "storemerge");
PN->addIncoming(SI.getOperand(0), SI.getParent());
PN->addIncoming(OtherStore->getOperand(0), OtherBB);
MergedVal = InsertNewInstBefore(PN, DestBB->front());
}
-
+
// Advance to a place where it is safe to insert the new store and
// insert it.
- BBI = DestBB->getFirstNonPHI();
- InsertNewInstBefore(new StoreInst(MergedVal, SI.getOperand(1),
- OtherStore->isVolatile(),
- SI.getAlignment()), *BBI);
-
+ BBI = DestBB->getFirstInsertionPt();
+ StoreInst *NewSI = new StoreInst(MergedVal, SI.getOperand(1),
+ SI.isVolatile(),
+ SI.getAlignment(),
+ SI.getOrdering(),
+ SI.getSynchScope());
+ InsertNewInstBefore(NewSI, *BBI);
+ NewSI->setDebugLoc(OtherStore->getDebugLoc());
+
+ // If the two stores had the same TBAA tag, preserve it.
+ if (MDNode *TBAATag = SI.getMetadata(LLVMContext::MD_tbaa))
+ if ((TBAATag = MDNode::getMostGenericTBAA(TBAATag,
+ OtherStore->getMetadata(LLVMContext::MD_tbaa))))
+ NewSI->setMetadata(LLVMContext::MD_tbaa, TBAATag);
+
+
// Nuke the old stores.
EraseInstFromFunction(SI);
EraseInstFromFunction(*OtherStore);
projects / oota-llvm.git / blobdiff