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path: root/lib/Transforms/InstCombine/InstructionCombining.cpp
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Diffstat (limited to 'lib/Transforms/InstCombine/InstructionCombining.cpp')
-rw-r--r--lib/Transforms/InstCombine/InstructionCombining.cpp114
1 files changed, 70 insertions, 44 deletions
diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp
index ec1075120282..191a101e0a30 100644
--- a/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -699,7 +699,10 @@ Instruction *InstCombiner::FoldOpIntoPhi(Instruction &I) {
Value *TrueVInPred = TrueV->DoPHITranslation(PhiTransBB, ThisBB);
Value *FalseVInPred = FalseV->DoPHITranslation(PhiTransBB, ThisBB);
Value *InV = 0;
- if (Constant *InC = dyn_cast<Constant>(PN->getIncomingValue(i)))
+ // Beware of ConstantExpr: it may eventually evaluate to getNullValue,
+ // even if currently isNullValue gives false.
+ Constant *InC = dyn_cast<Constant>(PN->getIncomingValue(i));
+ if (InC && !isa<ConstantExpr>(InC))
InV = InC->isNullValue() ? FalseVInPred : TrueVInPred;
else
InV = Builder->CreateSelect(PN->getIncomingValue(i),
@@ -755,19 +758,25 @@ Instruction *InstCombiner::FoldOpIntoPhi(Instruction &I) {
return ReplaceInstUsesWith(I, NewPN);
}
-/// FindElementAtOffset - Given a type and a constant offset, determine whether
-/// or not there is a sequence of GEP indices into the type that will land us at
-/// the specified offset. If so, fill them into NewIndices and return the
-/// resultant element type, otherwise return null.
-Type *InstCombiner::FindElementAtOffset(Type *Ty, int64_t Offset,
- SmallVectorImpl<Value*> &NewIndices) {
- if (!TD) return 0;
- if (!Ty->isSized()) return 0;
+/// FindElementAtOffset - Given a pointer type and a constant offset, determine
+/// whether or not there is a sequence of GEP indices into the pointed type that
+/// will land us at the specified offset. If so, fill them into NewIndices and
+/// return the resultant element type, otherwise return null.
+Type *InstCombiner::FindElementAtOffset(Type *PtrTy, int64_t Offset,
+ SmallVectorImpl<Value*> &NewIndices) {
+ assert(PtrTy->isPtrOrPtrVectorTy());
+
+ if (!TD)
+ return 0;
+
+ Type *Ty = PtrTy->getPointerElementType();
+ if (!Ty->isSized())
+ return 0;
// Start with the index over the outer type. Note that the type size
// might be zero (even if the offset isn't zero) if the indexed type
// is something like [0 x {int, int}]
- Type *IntPtrTy = TD->getIntPtrType(Ty->getContext());
+ Type *IntPtrTy = TD->getIntPtrType(PtrTy);
int64_t FirstIdx = 0;
if (int64_t TySize = TD->getTypeAllocSize(Ty)) {
FirstIdx = Offset/TySize;
@@ -1176,6 +1185,22 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
GetElementPtrInst::Create(Src->getOperand(0), Indices, GEP.getName());
}
+ // Canonicalize (gep i8* X, -(ptrtoint Y)) to (sub (ptrtoint X), (ptrtoint Y))
+ // The GEP pattern is emitted by the SCEV expander for certain kinds of
+ // pointer arithmetic.
+ if (TD && GEP.getNumIndices() == 1 &&
+ match(GEP.getOperand(1), m_Neg(m_PtrToInt(m_Value())))) {
+ unsigned AS = GEP.getPointerAddressSpace();
+ if (GEP.getType() == Builder->getInt8PtrTy(AS) &&
+ GEP.getOperand(1)->getType()->getScalarSizeInBits() ==
+ TD->getPointerSizeInBits(AS)) {
+ Operator *Index = cast<Operator>(GEP.getOperand(1));
+ Value *PtrToInt = Builder->CreatePtrToInt(PtrOp, Index->getType());
+ Value *NewSub = Builder->CreateSub(PtrToInt, Index->getOperand(1));
+ return CastInst::Create(Instruction::IntToPtr, NewSub, GEP.getType());
+ }
+ }
+
// Handle gep(bitcast x) and gep(gep x, 0, 0, 0).
Value *StrippedPtr = PtrOp->stripPointerCasts();
PointerType *StrippedPtrTy = dyn_cast<PointerType>(StrippedPtr->getType());
@@ -1231,13 +1256,12 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
// %t = getelementptr i32* bitcast ([2 x i32]* %str to i32*), i32 %V
// into: %t1 = getelementptr [2 x i32]* %str, i32 0, i32 %V; bitcast
Type *SrcElTy = StrippedPtrTy->getElementType();
- Type *ResElTy=cast<PointerType>(PtrOp->getType())->getElementType();
+ Type *ResElTy = PtrOp->getType()->getPointerElementType();
if (TD && SrcElTy->isArrayTy() &&
- TD->getTypeAllocSize(cast<ArrayType>(SrcElTy)->getElementType()) ==
+ TD->getTypeAllocSize(SrcElTy->getArrayElementType()) ==
TD->getTypeAllocSize(ResElTy)) {
- Value *Idx[2];
- Idx[0] = Constant::getNullValue(Type::getInt32Ty(GEP.getContext()));
- Idx[1] = GEP.getOperand(1);
+ Type *IdxType = TD->getIntPtrType(GEP.getType());
+ Value *Idx[2] = { Constant::getNullValue(IdxType), GEP.getOperand(1) };
Value *NewGEP = GEP.isInBounds() ?
Builder->CreateInBoundsGEP(StrippedPtr, Idx, GEP.getName()) :
Builder->CreateGEP(StrippedPtr, Idx, GEP.getName());
@@ -1261,7 +1285,7 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
// Earlier transforms ensure that the index has type IntPtrType, which
// considerably simplifies the logic by eliminating implicit casts.
- assert(Idx->getType() == TD->getIntPtrType(GEP.getContext()) &&
+ assert(Idx->getType() == TD->getIntPtrType(GEP.getType()) &&
"Index not cast to pointer width?");
bool NSW;
@@ -1287,8 +1311,8 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
// Check that changing to the array element type amounts to dividing the
// index by a scale factor.
uint64_t ResSize = TD->getTypeAllocSize(ResElTy);
- uint64_t ArrayEltSize =
- TD->getTypeAllocSize(cast<ArrayType>(SrcElTy)->getElementType());
+ uint64_t ArrayEltSize
+ = TD->getTypeAllocSize(SrcElTy->getArrayElementType());
if (ResSize && ArrayEltSize % ResSize == 0) {
Value *Idx = GEP.getOperand(1);
unsigned BitWidth = Idx->getType()->getPrimitiveSizeInBits();
@@ -1296,7 +1320,7 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
// Earlier transforms ensure that the index has type IntPtrType, which
// considerably simplifies the logic by eliminating implicit casts.
- assert(Idx->getType() == TD->getIntPtrType(GEP.getContext()) &&
+ assert(Idx->getType() == TD->getIntPtrType(GEP.getType()) &&
"Index not cast to pointer width?");
bool NSW;
@@ -1304,9 +1328,11 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
// Successfully decomposed Idx as NewIdx * Scale, form a new GEP.
// If the multiplication NewIdx * Scale may overflow then the new
// GEP may not be "inbounds".
- Value *Off[2];
- Off[0] = Constant::getNullValue(Type::getInt32Ty(GEP.getContext()));
- Off[1] = NewIdx;
+ Value *Off[2] = {
+ Constant::getNullValue(TD->getIntPtrType(GEP.getType())),
+ NewIdx
+ };
+
Value *NewGEP = GEP.isInBounds() && NSW ?
Builder->CreateInBoundsGEP(StrippedPtr, Off, GEP.getName()) :
Builder->CreateGEP(StrippedPtr, Off, GEP.getName());
@@ -1318,15 +1344,20 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
}
}
+ if (!TD)
+ return 0;
+
/// See if we can simplify:
/// X = bitcast A* to B*
/// Y = gep X, <...constant indices...>
/// into a gep of the original struct. This is important for SROA and alias
/// analysis of unions. If "A" is also a bitcast, wait for A/X to be merged.
if (BitCastInst *BCI = dyn_cast<BitCastInst>(PtrOp)) {
- APInt Offset(TD ? TD->getPointerSizeInBits() : 1, 0);
- if (TD &&
- !isa<BitCastInst>(BCI->getOperand(0)) &&
+ Value *Operand = BCI->getOperand(0);
+ PointerType *OpType = cast<PointerType>(Operand->getType());
+ unsigned OffsetBits = TD->getPointerTypeSizeInBits(OpType);
+ APInt Offset(OffsetBits, 0);
+ if (!isa<BitCastInst>(Operand) &&
GEP.accumulateConstantOffset(*TD, Offset) &&
StrippedPtrTy->getAddressSpace() == GEP.getPointerAddressSpace()) {
@@ -1335,8 +1366,7 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
if (!Offset) {
// If the bitcast is of an allocation, and the allocation will be
// converted to match the type of the cast, don't touch this.
- if (isa<AllocaInst>(BCI->getOperand(0)) ||
- isAllocationFn(BCI->getOperand(0), TLI)) {
+ if (isa<AllocaInst>(Operand) || isAllocationFn(Operand, TLI)) {
// See if the bitcast simplifies, if so, don't nuke this GEP yet.
if (Instruction *I = visitBitCast(*BCI)) {
if (I != BCI) {
@@ -1347,19 +1377,17 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
return &GEP;
}
}
- return new BitCastInst(BCI->getOperand(0), GEP.getType());
+ return new BitCastInst(Operand, GEP.getType());
}
// Otherwise, if the offset is non-zero, we need to find out if there is a
// field at Offset in 'A's type. If so, we can pull the cast through the
// GEP.
SmallVector<Value*, 8> NewIndices;
- Type *InTy =
- cast<PointerType>(BCI->getOperand(0)->getType())->getElementType();
- if (FindElementAtOffset(InTy, Offset.getSExtValue(), NewIndices)) {
+ if (FindElementAtOffset(OpType, Offset.getSExtValue(), NewIndices)) {
Value *NGEP = GEP.isInBounds() ?
- Builder->CreateInBoundsGEP(BCI->getOperand(0), NewIndices) :
- Builder->CreateGEP(BCI->getOperand(0), NewIndices);
+ Builder->CreateInBoundsGEP(Operand, NewIndices) :
+ Builder->CreateGEP(Operand, NewIndices);
if (NGEP->getType() == GEP.getType())
return ReplaceInstUsesWith(GEP, NGEP);
@@ -1372,8 +1400,6 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
return 0;
}
-
-
static bool
isAllocSiteRemovable(Instruction *AI, SmallVectorImpl<WeakVH> &Users,
const TargetLibraryInfo *TLI) {
@@ -2042,7 +2068,7 @@ Instruction *InstCombiner::visitLandingPadInst(LandingPadInst &LI) {
continue;
// If Filter is a subset of LFilter, i.e. every element of Filter is also
// an element of LFilter, then discard LFilter.
- SmallVector<Value *, 16>::iterator J = NewClauses.begin() + j;
+ SmallVectorImpl<Value *>::iterator J = NewClauses.begin() + j;
// If Filter is empty then it is a subset of LFilter.
if (!FElts) {
// Discard LFilter.
@@ -2209,7 +2235,7 @@ static bool AddReachableCodeToWorklist(BasicBlock *BB,
// DCE instruction if trivially dead.
if (isInstructionTriviallyDead(Inst, TLI)) {
++NumDeadInst;
- DEBUG(errs() << "IC: DCE: " << *Inst << '\n');
+ DEBUG(dbgs() << "IC: DCE: " << *Inst << '\n');
Inst->eraseFromParent();
continue;
}
@@ -2217,7 +2243,7 @@ static bool AddReachableCodeToWorklist(BasicBlock *BB,
// ConstantProp instruction if trivially constant.
if (!Inst->use_empty() && isa<Constant>(Inst->getOperand(0)))
if (Constant *C = ConstantFoldInstruction(Inst, TD, TLI)) {
- DEBUG(errs() << "IC: ConstFold to: " << *C << " from: "
+ DEBUG(dbgs() << "IC: ConstFold to: " << *C << " from: "
<< *Inst << '\n');
Inst->replaceAllUsesWith(C);
++NumConstProp;
@@ -2293,7 +2319,7 @@ static bool AddReachableCodeToWorklist(BasicBlock *BB,
bool InstCombiner::DoOneIteration(Function &F, unsigned Iteration) {
MadeIRChange = false;
- DEBUG(errs() << "\n\nINSTCOMBINE ITERATION #" << Iteration << " on "
+ DEBUG(dbgs() << "\n\nINSTCOMBINE ITERATION #" << Iteration << " on "
<< F.getName() << "\n");
{
@@ -2338,7 +2364,7 @@ bool InstCombiner::DoOneIteration(Function &F, unsigned Iteration) {
// Check to see if we can DCE the instruction.
if (isInstructionTriviallyDead(I, TLI)) {
- DEBUG(errs() << "IC: DCE: " << *I << '\n');
+ DEBUG(dbgs() << "IC: DCE: " << *I << '\n');
EraseInstFromFunction(*I);
++NumDeadInst;
MadeIRChange = true;
@@ -2348,7 +2374,7 @@ bool InstCombiner::DoOneIteration(Function &F, unsigned Iteration) {
// Instruction isn't dead, see if we can constant propagate it.
if (!I->use_empty() && isa<Constant>(I->getOperand(0)))
if (Constant *C = ConstantFoldInstruction(I, TD, TLI)) {
- DEBUG(errs() << "IC: ConstFold to: " << *C << " from: " << *I << '\n');
+ DEBUG(dbgs() << "IC: ConstFold to: " << *C << " from: " << *I << '\n');
// Add operands to the worklist.
ReplaceInstUsesWith(*I, C);
@@ -2396,13 +2422,13 @@ bool InstCombiner::DoOneIteration(Function &F, unsigned Iteration) {
std::string OrigI;
#endif
DEBUG(raw_string_ostream SS(OrigI); I->print(SS); OrigI = SS.str(););
- DEBUG(errs() << "IC: Visiting: " << OrigI << '\n');
+ DEBUG(dbgs() << "IC: Visiting: " << OrigI << '\n');
if (Instruction *Result = visit(*I)) {
++NumCombined;
// Should we replace the old instruction with a new one?
if (Result != I) {
- DEBUG(errs() << "IC: Old = " << *I << '\n'
+ DEBUG(dbgs() << "IC: Old = " << *I << '\n'
<< " New = " << *Result << '\n');
if (!I->getDebugLoc().isUnknown())
@@ -2431,7 +2457,7 @@ bool InstCombiner::DoOneIteration(Function &F, unsigned Iteration) {
EraseInstFromFunction(*I);
} else {
#ifndef NDEBUG
- DEBUG(errs() << "IC: Mod = " << OrigI << '\n'
+ DEBUG(dbgs() << "IC: Mod = " << OrigI << '\n'
<< " New = " << *I << '\n');
#endif
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-17 15:57:29 +0000