//
//===----------------------------------------------------------------------===//
-#include "InstCombine.h"
+#include "InstCombineInternal.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/PatternMatch.h"
/// try to eliminate the cast by moving the type information into the alloc.
Instruction *InstCombiner::PromoteCastOfAllocation(BitCastInst &CI,
AllocaInst &AI) {
- // This requires DataLayout to get the alloca alignment and size information.
- if (!DL) return nullptr;
-
PointerType *PTy = cast<PointerType>(CI.getType());
BuilderTy AllocaBuilder(*Builder);
Type *CastElTy = PTy->getElementType();
if (!AllocElTy->isSized() || !CastElTy->isSized()) return nullptr;
- unsigned AllocElTyAlign = DL->getABITypeAlignment(AllocElTy);
- unsigned CastElTyAlign = DL->getABITypeAlignment(CastElTy);
+ unsigned AllocElTyAlign = DL.getABITypeAlignment(AllocElTy);
+ unsigned CastElTyAlign = DL.getABITypeAlignment(CastElTy);
if (CastElTyAlign < AllocElTyAlign) return nullptr;
// If the allocation has multiple uses, only promote it if we are strictly
// same, we open the door to infinite loops of various kinds.
if (!AI.hasOneUse() && CastElTyAlign == AllocElTyAlign) return nullptr;
- uint64_t AllocElTySize = DL->getTypeAllocSize(AllocElTy);
- uint64_t CastElTySize = DL->getTypeAllocSize(CastElTy);
+ uint64_t AllocElTySize = DL.getTypeAllocSize(AllocElTy);
+ uint64_t CastElTySize = DL.getTypeAllocSize(CastElTy);
if (CastElTySize == 0 || AllocElTySize == 0) return nullptr;
// If the allocation has multiple uses, only promote it if we're not
// shrinking the amount of memory being allocated.
- uint64_t AllocElTyStoreSize = DL->getTypeStoreSize(AllocElTy);
- uint64_t CastElTyStoreSize = DL->getTypeStoreSize(CastElTy);
+ uint64_t AllocElTyStoreSize = DL.getTypeStoreSize(AllocElTy);
+ uint64_t CastElTyStoreSize = DL.getTypeStoreSize(CastElTy);
if (!AI.hasOneUse() && CastElTyStoreSize < AllocElTyStoreSize) return nullptr;
// See if we can satisfy the modulus by pulling a scale out of the array
PHINode *OPN = cast<PHINode>(I);
PHINode *NPN = PHINode::Create(Ty, OPN->getNumIncomingValues());
for (unsigned i = 0, e = OPN->getNumIncomingValues(); i != e; ++i) {
- Value *V =EvaluateInDifferentType(OPN->getIncomingValue(i), Ty, isSigned);
+ Value *V =
+ EvaluateInDifferentType(OPN->getIncomingValue(i), Ty, isSigned);
NPN->addIncoming(V, OPN->getIncomingBlock(i));
}
Res = NPN;
/// This function is a wrapper around CastInst::isEliminableCastPair. It
/// simply extracts arguments and returns what that function returns.
static Instruction::CastOps
-isEliminableCastPair(
- const CastInst *CI, ///< The first cast instruction
- unsigned opcode, ///< The opcode of the second cast instruction
- Type *DstTy, ///< The target type for the second cast instruction
- const DataLayout *DL ///< The target data for pointer size
-) {
-
+isEliminableCastPair(const CastInst *CI, ///< First cast instruction
+ unsigned opcode, ///< Opcode for the second cast
+ Type *DstTy, ///< Target type for the second cast
+ const DataLayout &DL) {
Type *SrcTy = CI->getOperand(0)->getType(); // A from above
Type *MidTy = CI->getType(); // B from above
// Get the opcodes of the two Cast instructions
Instruction::CastOps firstOp = Instruction::CastOps(CI->getOpcode());
Instruction::CastOps secondOp = Instruction::CastOps(opcode);
- Type *SrcIntPtrTy = DL && SrcTy->isPtrOrPtrVectorTy() ?
- DL->getIntPtrType(SrcTy) : nullptr;
- Type *MidIntPtrTy = DL && MidTy->isPtrOrPtrVectorTy() ?
- DL->getIntPtrType(MidTy) : nullptr;
- Type *DstIntPtrTy = DL && DstTy->isPtrOrPtrVectorTy() ?
- DL->getIntPtrType(DstTy) : nullptr;
+ Type *SrcIntPtrTy =
+ SrcTy->isPtrOrPtrVectorTy() ? DL.getIntPtrType(SrcTy) : nullptr;
+ Type *MidIntPtrTy =
+ MidTy->isPtrOrPtrVectorTy() ? DL.getIntPtrType(MidTy) : nullptr;
+ Type *DstIntPtrTy =
+ DstTy->isPtrOrPtrVectorTy() ? DL.getIntPtrType(DstTy) : nullptr;
unsigned Res = CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy,
DstTy, SrcIntPtrTy, MidIntPtrTy,
DstIntPtrTy);
// eliminate it now.
if (CastInst *CSrc = dyn_cast<CastInst>(Src)) { // A->B->C cast
if (Instruction::CastOps opc =
- isEliminableCastPair(CSrc, CI.getOpcode(), CI.getType(), DL)) {
+ isEliminableCastPair(CSrc, CI.getOpcode(), CI.getType(), DL)) {
// The first cast (CSrc) is eliminable so we need to fix up or replace
// the second cast (CI). CSrc will then have a good chance of being dead.
return CastInst::Create(opc, CSrc->getOperand(0), CI.getType());
if (isa<PHINode>(Src)) {
// We don't do this if this would create a PHI node with an illegal type if
// it is currently legal.
- if (!Src->getType()->isIntegerTy() ||
- !CI.getType()->isIntegerTy() ||
+ if (!Src->getType()->isIntegerTy() || !CI.getType()->isIntegerTy() ||
ShouldChangeType(CI.getType(), Src->getType()))
if (Instruction *NV = FoldOpIntoPhi(CI))
return NV;
Value *Src = CI.getOperand(0);
Type *SrcTy = Src->getType(), *DestTy = CI.getType();
+ // If we know that the value being extended is positive, we can use a zext
+ // instead.
+ bool KnownZero, KnownOne;
+ ComputeSignBit(Src, KnownZero, KnownOne, 0, &CI);
+ if (KnownZero) {
+ Value *ZExt = Builder->CreateZExt(Src, DestTy);
+ return ReplaceInstUsesWith(CI, ZExt);
+ }
+
// Attempt to extend the entire input expression tree to the destination
// type. Only do this if the dest type is a simple type, don't convert the
// expression tree to something weird like i93 unless the source is also
return commonCastTransforms(CI);
}
+// fpto{s/u}i({u/s}itofp(X)) --> X or zext(X) or sext(X) or trunc(X)
+// This is safe if the intermediate type has enough bits in its mantissa to
+// accurately represent all values of X. For example, this won't work with
+// i64 -> float -> i64.
+Instruction *InstCombiner::FoldItoFPtoI(Instruction &FI) {
+ if (!isa<UIToFPInst>(FI.getOperand(0)) && !isa<SIToFPInst>(FI.getOperand(0)))
+ return nullptr;
+ Instruction *OpI = cast<Instruction>(FI.getOperand(0));
+
+ Value *SrcI = OpI->getOperand(0);
+ Type *FITy = FI.getType();
+ Type *OpITy = OpI->getType();
+ Type *SrcTy = SrcI->getType();
+ bool IsInputSigned = isa<SIToFPInst>(OpI);
+ bool IsOutputSigned = isa<FPToSIInst>(FI);
+
+ // We can safely assume the conversion won't overflow the output range,
+ // because (for example) (uint8_t)18293.f is undefined behavior.
+
+ // Since we can assume the conversion won't overflow, our decision as to
+ // whether the input will fit in the float should depend on the minimum
+ // of the input range and output range.
+
+ // This means this is also safe for a signed input and unsigned output, since
+ // a negative input would lead to undefined behavior.
+ int InputSize = (int)SrcTy->getScalarSizeInBits() - IsInputSigned;
+ int OutputSize = (int)FITy->getScalarSizeInBits() - IsOutputSigned;
+ int ActualSize = std::min(InputSize, OutputSize);
+
+ if (ActualSize <= OpITy->getFPMantissaWidth()) {
+ if (FITy->getScalarSizeInBits() > SrcTy->getScalarSizeInBits()) {
+ if (IsInputSigned && IsOutputSigned)
+ return new SExtInst(SrcI, FITy);
+ return new ZExtInst(SrcI, FITy);
+ }
+ if (FITy->getScalarSizeInBits() < SrcTy->getScalarSizeInBits())
+ return new TruncInst(SrcI, FITy);
+ if (SrcTy == FITy)
+ return ReplaceInstUsesWith(FI, SrcI);
+ return new BitCastInst(SrcI, FITy);
+ }
+ return nullptr;
+}
+
Instruction *InstCombiner::visitFPToUI(FPToUIInst &FI) {
Instruction *OpI = dyn_cast<Instruction>(FI.getOperand(0));
if (!OpI)
return commonCastTransforms(FI);
- // fptoui(uitofp(X)) --> X
- // fptoui(sitofp(X)) --> X
- // This is safe if the intermediate type has enough bits in its mantissa to
- // accurately represent all values of X. For example, do not do this with
- // i64->float->i64. This is also safe for sitofp case, because any negative
- // 'X' value would cause an undefined result for the fptoui.
- if ((isa<UIToFPInst>(OpI) || isa<SIToFPInst>(OpI)) &&
- OpI->getOperand(0)->getType() == FI.getType() &&
- (int)FI.getType()->getScalarSizeInBits() < /*extra bit for sign */
- OpI->getType()->getFPMantissaWidth())
- return ReplaceInstUsesWith(FI, OpI->getOperand(0));
+ if (Instruction *I = FoldItoFPtoI(FI))
+ return I;
return commonCastTransforms(FI);
}
if (!OpI)
return commonCastTransforms(FI);
- // fptosi(sitofp(X)) --> X
- // fptosi(uitofp(X)) --> X
- // This is safe if the intermediate type has enough bits in its mantissa to
- // accurately represent all values of X. For example, do not do this with
- // i64->float->i64. This is also safe for sitofp case, because any negative
- // 'X' value would cause an undefined result for the fptoui.
- if ((isa<UIToFPInst>(OpI) || isa<SIToFPInst>(OpI)) &&
- OpI->getOperand(0)->getType() == FI.getType() &&
- (int)FI.getType()->getScalarSizeInBits() <=
- OpI->getType()->getFPMantissaWidth())
- return ReplaceInstUsesWith(FI, OpI->getOperand(0));
+ if (Instruction *I = FoldItoFPtoI(FI))
+ return I;
return commonCastTransforms(FI);
}
// If the source integer type is not the intptr_t type for this target, do a
// trunc or zext to the intptr_t type, then inttoptr of it. This allows the
// cast to be exposed to other transforms.
-
- if (DL) {
- unsigned AS = CI.getAddressSpace();
- if (CI.getOperand(0)->getType()->getScalarSizeInBits() !=
- DL->getPointerSizeInBits(AS)) {
- Type *Ty = DL->getIntPtrType(CI.getContext(), AS);
- if (CI.getType()->isVectorTy()) // Handle vectors of pointers.
- Ty = VectorType::get(Ty, CI.getType()->getVectorNumElements());
-
- Value *P = Builder->CreateZExtOrTrunc(CI.getOperand(0), Ty);
- return new IntToPtrInst(P, CI.getType());
- }
+ unsigned AS = CI.getAddressSpace();
+ if (CI.getOperand(0)->getType()->getScalarSizeInBits() !=
+ DL.getPointerSizeInBits(AS)) {
+ Type *Ty = DL.getIntPtrType(CI.getContext(), AS);
+ if (CI.getType()->isVectorTy()) // Handle vectors of pointers.
+ Ty = VectorType::get(Ty, CI.getType()->getVectorNumElements());
+
+ Value *P = Builder->CreateZExtOrTrunc(CI.getOperand(0), Ty);
+ return new IntToPtrInst(P, CI.getType());
}
if (Instruction *I = commonCastTransforms(CI))
return &CI;
}
- if (!DL)
- return commonCastTransforms(CI);
-
// If the GEP has a single use, and the base pointer is a bitcast, and the
// GEP computes a constant offset, see if we can convert these three
// instructions into fewer. This typically happens with unions and other
// non-type-safe code.
unsigned AS = GEP->getPointerAddressSpace();
- unsigned OffsetBits = DL->getPointerSizeInBits(AS);
+ unsigned OffsetBits = DL.getPointerSizeInBits(AS);
APInt Offset(OffsetBits, 0);
BitCastInst *BCI = dyn_cast<BitCastInst>(GEP->getOperand(0));
- if (GEP->hasOneUse() &&
- BCI &&
- GEP->accumulateConstantOffset(*DL, Offset)) {
+ if (GEP->hasOneUse() && BCI && GEP->accumulateConstantOffset(DL, Offset)) {
+ // FIXME: This is insufficiently tested - just a no-crash test
+ // (test/Transforms/InstCombine/2007-05-14-Crash.ll)
+ //
// Get the base pointer input of the bitcast, and the type it points to.
Value *OrigBase = BCI->getOperand(0);
SmallVector<Value*, 8> NewIndices;
- if (FindElementAtOffset(OrigBase->getType(),
- Offset.getSExtValue(),
+ if (FindElementAtOffset(OrigBase->getType(), Offset.getSExtValue(),
NewIndices)) {
+ // FIXME: This codepath is completely untested - could be unreachable
+ // for all I know.
// If we were able to index down into an element, create the GEP
// and bitcast the result. This eliminates one bitcast, potentially
// two.
// do a ptrtoint to intptr_t then do a trunc or zext. This allows the cast
// to be exposed to other transforms.
- if (!DL)
- return commonPointerCastTransforms(CI);
-
Type *Ty = CI.getType();
unsigned AS = CI.getPointerAddressSpace();
- if (Ty->getScalarSizeInBits() == DL->getPointerSizeInBits(AS))
+ if (Ty->getScalarSizeInBits() == DL.getPointerSizeInBits(AS))
return commonPointerCastTransforms(CI);
- Type *PtrTy = DL->getIntPtrType(CI.getContext(), AS);
+ Type *PtrTy = DL.getIntPtrType(CI.getContext(), AS);
if (Ty->isVectorTy()) // Handle vectors of pointers.
PtrTy = VectorType::get(PtrTy, Ty->getVectorNumElements());
/// This returns false if the pattern can't be matched or true if it can,
/// filling in Elements with the elements found here.
static bool CollectInsertionElements(Value *V, unsigned Shift,
- SmallVectorImpl<Value*> &Elements,
- Type *VecEltTy, InstCombiner &IC) {
+ SmallVectorImpl<Value *> &Elements,
+ Type *VecEltTy, bool isBigEndian) {
assert(isMultipleOfTypeSize(Shift, VecEltTy) &&
"Shift should be a multiple of the element type size");
return true;
unsigned ElementIndex = getTypeSizeIndex(Shift, VecEltTy);
- if (IC.getDataLayout()->isBigEndian())
+ if (isBigEndian)
ElementIndex = Elements.size() - ElementIndex - 1;
// Fail if multiple elements are inserted into this slot.
// it to the right type so it gets properly inserted.
if (NumElts == 1)
return CollectInsertionElements(ConstantExpr::getBitCast(C, VecEltTy),
- Shift, Elements, VecEltTy, IC);
+ Shift, Elements, VecEltTy, isBigEndian);
// Okay, this is a constant that covers multiple elements. Slice it up into
// pieces and insert each element-sized piece into the vector.
Constant *Piece = ConstantExpr::getLShr(C, ConstantInt::get(C->getType(),
ShiftI));
Piece = ConstantExpr::getTrunc(Piece, ElementIntTy);
- if (!CollectInsertionElements(Piece, ShiftI, Elements, VecEltTy, IC))
+ if (!CollectInsertionElements(Piece, ShiftI, Elements, VecEltTy,
+ isBigEndian))
return false;
}
return true;
switch (I->getOpcode()) {
default: return false; // Unhandled case.
case Instruction::BitCast:
- return CollectInsertionElements(I->getOperand(0), Shift,
- Elements, VecEltTy, IC);
+ return CollectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
+ isBigEndian);
case Instruction::ZExt:
if (!isMultipleOfTypeSize(
I->getOperand(0)->getType()->getPrimitiveSizeInBits(),
VecEltTy))
return false;
- return CollectInsertionElements(I->getOperand(0), Shift,
- Elements, VecEltTy, IC);
+ return CollectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
+ isBigEndian);
case Instruction::Or:
- return CollectInsertionElements(I->getOperand(0), Shift,
- Elements, VecEltTy, IC) &&
- CollectInsertionElements(I->getOperand(1), Shift,
- Elements, VecEltTy, IC);
+ return CollectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
+ isBigEndian) &&
+ CollectInsertionElements(I->getOperand(1), Shift, Elements, VecEltTy,
+ isBigEndian);
case Instruction::Shl: {
// Must be shifting by a constant that is a multiple of the element size.
ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1));
if (!CI) return false;
Shift += CI->getZExtValue();
if (!isMultipleOfTypeSize(Shift, VecEltTy)) return false;
- return CollectInsertionElements(I->getOperand(0), Shift,
- Elements, VecEltTy, IC);
+ return CollectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
+ isBigEndian);
}
}
/// Into two insertelements that do "buildvector{%inc, %inc5}".
static Value *OptimizeIntegerToVectorInsertions(BitCastInst &CI,
InstCombiner &IC) {
- // We need to know the target byte order to perform this optimization.
- if (!IC.getDataLayout()) return nullptr;
-
VectorType *DestVecTy = cast<VectorType>(CI.getType());
Value *IntInput = CI.getOperand(0);
SmallVector<Value*, 8> Elements(DestVecTy->getNumElements());
if (!CollectInsertionElements(IntInput, 0, Elements,
- DestVecTy->getElementType(), IC))
+ DestVecTy->getElementType(),
+ IC.getDataLayout().isBigEndian()))
return nullptr;
// If we succeeded, we know that all of the element are specified by Elements
/// OptimizeIntToFloatBitCast - See if we can optimize an integer->float/double
/// bitcast. The various long double bitcasts can't get in here.
-static Instruction *OptimizeIntToFloatBitCast(BitCastInst &CI,InstCombiner &IC){
- // We need to know the target byte order to perform this optimization.
- if (!IC.getDataLayout()) return nullptr;
-
+static Instruction *OptimizeIntToFloatBitCast(BitCastInst &CI, InstCombiner &IC,
+ const DataLayout &DL) {
Value *Src = CI.getOperand(0);
Type *DestTy = CI.getType();
}
unsigned Elt = 0;
- if (IC.getDataLayout()->isBigEndian())
+ if (DL.isBigEndian())
Elt = VecTy->getPrimitiveSizeInBits() / DestWidth - 1;
return ExtractElementInst::Create(VecInput, IC.Builder->getInt32(Elt));
}
}
unsigned Elt = ShAmt->getZExtValue() / DestWidth;
- if (IC.getDataLayout()->isBigEndian())
+ if (DL.isBigEndian())
Elt = VecTy->getPrimitiveSizeInBits() / DestWidth - 1 - Elt;
return ExtractElementInst::Create(VecInput, IC.Builder->getInt32(Elt));
}
// Try to optimize int -> float bitcasts.
if ((DestTy->isFloatTy() || DestTy->isDoubleTy()) && isa<IntegerType>(SrcTy))
- if (Instruction *I = OptimizeIntToFloatBitCast(CI, *this))
+ if (Instruction *I = OptimizeIntToFloatBitCast(CI, *this, DL))
return I;
if (VectorType *DestVTy = dyn_cast<VectorType>(DestTy)) {
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