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[AMDGPUPromoteAlloca][NFC] Avoid unnecessary APInt/int64_t conversions #157864

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Sep 12, 2025
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[AMDGPUPromoteAlloca][NFC] Avoid unnecessary APInt/int64_t conversions #157864

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22 changes: 10 additions & 12 deletions llvm/lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -406,6 +406,7 @@ static Value *GEPToVectorIndex(GetElementPtrInst *GEP, AllocaInst *Alloca,
SmallVector<Instruction *> &NewInsts) {
// TODO: Extracting a "multiple of X" from a GEP might be a useful generic
// helper.
LLVMContext &Ctx = GEP->getContext();
unsigned BW = DL.getIndexTypeSizeInBits(GEP->getType());
SmallMapVector<Value *, APInt, 4> VarOffsets;
APInt ConstOffset(BW, 0);
Expand Down Expand Up @@ -438,27 +439,24 @@ static Value *GEPToVectorIndex(GetElementPtrInst *GEP, AllocaInst *Alloca,

assert(CurPtr == Alloca && "GEP not based on alloca");

unsigned VecElemSize = DL.getTypeAllocSize(VecElemTy);
int64_t VecElemSize = DL.getTypeAllocSize(VecElemTy);
if (VarOffsets.size() > 1)
return nullptr;

APInt IndexQuot;
APInt Rem;
APInt::sdivrem(ConstOffset, APInt(ConstOffset.getBitWidth(), VecElemSize),
IndexQuot, Rem);
if (!Rem.isZero())
int64_t Rem;
APInt::sdivrem(ConstOffset, VecElemSize, IndexQuot, Rem);
if (Rem != 0)
return nullptr;
if (VarOffsets.size() == 0)
return ConstantInt::get(GEP->getContext(), IndexQuot);
return ConstantInt::get(Ctx, IndexQuot);

IRBuilder<> Builder(GEP);

const auto &VarOffset = VarOffsets.front();
APInt OffsetQuot;
APInt::sdivrem(VarOffset.second,
APInt(VarOffset.second.getBitWidth(), VecElemSize), OffsetQuot,
Rem);
if (!Rem.isZero() || OffsetQuot.isZero())
APInt::sdivrem(VarOffset.second, VecElemSize, OffsetQuot, Rem);
if (Rem != 0 || OffsetQuot.isZero())
return nullptr;

Value *Offset = VarOffset.first;
Expand All @@ -468,7 +466,7 @@ static Value *GEPToVectorIndex(GetElementPtrInst *GEP, AllocaInst *Alloca,

if (!OffsetQuot.isOne()) {
ConstantInt *ConstMul =
ConstantInt::get(OffsetType, OffsetQuot.getSExtValue());
ConstantInt::get(Ctx, OffsetQuot.sext(OffsetType->getBitWidth()));
Offset = Builder.CreateMul(Offset, ConstMul);
if (Instruction *NewInst = dyn_cast<Instruction>(Offset))
NewInsts.push_back(NewInst);
Expand All @@ -477,7 +475,7 @@ static Value *GEPToVectorIndex(GetElementPtrInst *GEP, AllocaInst *Alloca,
return Offset;

ConstantInt *ConstIndex =
ConstantInt::get(OffsetType, IndexQuot.getSExtValue());
ConstantInt::get(Ctx, IndexQuot.sext(OffsetType->getBitWidth()));
Value *IndexAdd = Builder.CreateAdd(Offset, ConstIndex);
if (Instruction *NewInst = dyn_cast<Instruction>(IndexAdd))
NewInsts.push_back(NewInst);
Expand Down