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[NFC][LLVM] Refactor IRBuilder::Create{VScale,ElementCount,TypeSize}. #142803

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[NFC][LLVM] Refactor IRBuilder::Create{VScale,ElementCount,TypeSize}. #142803

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0819cda
[NFC][LLVM] Refactor IRBuilder::Create{VScale,ElementCount,TypeSize}.
paulwalker-arm Jun 4, 2025
a3188cf
Inline CreateVScale, add utility function, remove unnecessary casts.
paulwalker-arm Jun 5, 2025
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10 changes: 2 additions & 8 deletions clang/lib/CodeGen/TargetBuiltins/ARM.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4792,12 +4792,7 @@ Value *CodeGenFunction::EmitAArch64SVEBuiltinExpr(unsigned BuiltinID,
case SVE::BI__builtin_sve_svlen_u32:
case SVE::BI__builtin_sve_svlen_u64: {
SVETypeFlags TF(Builtin->TypeModifier);
auto VTy = cast<llvm::VectorType>(getSVEType(TF));
auto *NumEls =
llvm::ConstantInt::get(Ty, VTy->getElementCount().getKnownMinValue());

Function *F = CGM.getIntrinsic(Intrinsic::vscale, Ty);
return Builder.CreateMul(NumEls, Builder.CreateCall(F));
return Builder.CreateElementCount(Ty, getSVEType(TF)->getElementCount());
}

case SVE::BI__builtin_sve_svtbl2_u8:
Expand All @@ -4813,8 +4808,7 @@ Value *CodeGenFunction::EmitAArch64SVEBuiltinExpr(unsigned BuiltinID,
case SVE::BI__builtin_sve_svtbl2_f32:
case SVE::BI__builtin_sve_svtbl2_f64: {
SVETypeFlags TF(Builtin->TypeModifier);
auto VTy = cast<llvm::ScalableVectorType>(getSVEType(TF));
Function *F = CGM.getIntrinsic(Intrinsic::aarch64_sve_tbl2, VTy);
Function *F = CGM.getIntrinsic(Intrinsic::aarch64_sve_tbl2, getSVEType(TF));
return Builder.CreateCall(F, Ops);
}

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11 changes: 6 additions & 5 deletions llvm/include/llvm/IR/IRBuilder.h
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Expand Up @@ -945,17 +945,18 @@ class IRBuilderBase {
LLVM_ABI CallInst *CreateGCGetPointerOffset(Value *DerivedPtr,
const Twine &Name = "");

/// Create a call to llvm.vscale, multiplied by \p Scaling. The type of VScale
/// will be the same type as that of \p Scaling.
LLVM_ABI Value *CreateVScale(Constant *Scaling, const Twine &Name = "");
/// Create a call to llvm.vscale.<Ty>().
LLVM_ABI Value *CreateVScale(Type *Ty, const Twine &Name = "") {
return CreateIntrinsic(Intrinsic::vscale, {Ty}, {}, {}, Name);
}

/// Create an expression which evaluates to the number of elements in \p EC
/// at runtime.
LLVM_ABI Value *CreateElementCount(Type *DstType, ElementCount EC);
LLVM_ABI Value *CreateElementCount(Type *Ty, ElementCount EC);

/// Create an expression which evaluates to the number of units in \p Size
/// at runtime. This works for both units of bits and bytes.
LLVM_ABI Value *CreateTypeSize(Type *DstType, TypeSize Size);
LLVM_ABI Value *CreateTypeSize(Type *Ty, TypeSize Size);

/// Creates a vector of type \p DstType with the linear sequence <0, 1, ...>
LLVM_ABI Value *CreateStepVector(Type *DstType, const Twine &Name = "");
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3 changes: 1 addition & 2 deletions llvm/lib/CodeGen/ExpandVectorPredication.cpp
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Expand Up @@ -507,8 +507,7 @@ bool CachingVPExpander::discardEVLParameter(VPIntrinsic &VPI) {
// TODO add caching
IRBuilder<> Builder(VPI.getParent(), VPI.getIterator());
Value *FactorConst = Builder.getInt32(StaticElemCount.getKnownMinValue());
Value *VScale = Builder.CreateIntrinsic(Intrinsic::vscale, Int32Ty, {},
/*FMFSource=*/nullptr, "vscale");
Value *VScale = Builder.CreateVScale(Int32Ty, "vscale");
MaxEVL = Builder.CreateMul(VScale, FactorConst, "scalable_size",
/*NUW*/ true, /*NSW*/ false);
} else {
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29 changes: 16 additions & 13 deletions llvm/lib/IR/IRBuilder.cpp
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Expand Up @@ -120,23 +120,26 @@ IRBuilderBase::createCallHelper(Function *Callee, ArrayRef<Value *> Ops,
return CI;
}

Value *IRBuilderBase::CreateVScale(Constant *Scaling, const Twine &Name) {
assert(isa<ConstantInt>(Scaling) && "Expected constant integer");
if (cast<ConstantInt>(Scaling)->isZero())
return Scaling;
CallInst *CI =
CreateIntrinsic(Intrinsic::vscale, {Scaling->getType()}, {}, {}, Name);
return cast<ConstantInt>(Scaling)->isOne() ? CI : CreateMul(CI, Scaling);
static Value *CreateVScaleMultiple(IRBuilderBase &B, Type *Ty, uint64_t Scale) {
Value *VScale = B.CreateVScale(Ty);
if (Scale == 1)
return VScale;

return B.CreateMul(VScale, ConstantInt::get(Ty, Scale));
}

Value *IRBuilderBase::CreateElementCount(Type *DstType, ElementCount EC) {
Constant *MinEC = ConstantInt::get(DstType, EC.getKnownMinValue());
return EC.isScalable() ? CreateVScale(MinEC) : MinEC;
Value *IRBuilderBase::CreateElementCount(Type *Ty, ElementCount EC) {
if (EC.isFixed() || EC.isZero())
return ConstantInt::get(Ty, EC.getKnownMinValue());

return CreateVScaleMultiple(*this, Ty, EC.getKnownMinValue());
}

Value *IRBuilderBase::CreateTypeSize(Type *DstType, TypeSize Size) {
Constant *MinSize = ConstantInt::get(DstType, Size.getKnownMinValue());
return Size.isScalable() ? CreateVScale(MinSize) : MinSize;
Value *IRBuilderBase::CreateTypeSize(Type *Ty, TypeSize Size) {
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This is just suggestion, so please feel free to ignore it, but given how similar the two functions are, would it be useful to write a common helper such as

  Value *CreateVScaleMultiple(Type *Ty, uint64_t Scale) {
    Value *VScale = CreateVScale(Ty);
    if (Scale == 1)
      return VScale;

    return CreateMul(VScale, ConstantInt::get(Ty, Scale));
  }

and reusing this in both CreateTypeSize and CreateElementCount?

if (Size.isFixed() || Size.isZero())
return ConstantInt::get(Ty, Size.getKnownMinValue());

return CreateVScaleMultiple(*this, Ty, Size.getKnownMinValue());
}

Value *IRBuilderBase::CreateStepVector(Type *DstType, const Twine &Name) {
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8 changes: 4 additions & 4 deletions llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
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Expand Up @@ -2051,10 +2051,10 @@ instCombineSVECntElts(InstCombiner &IC, IntrinsicInst &II, unsigned NumElts) {
const auto Pattern = cast<ConstantInt>(II.getArgOperand(0))->getZExtValue();

if (Pattern == AArch64SVEPredPattern::all) {
Constant *StepVal = ConstantInt::get(II.getType(), NumElts);
auto *VScale = IC.Builder.CreateVScale(StepVal);
VScale->takeName(&II);
return IC.replaceInstUsesWith(II, VScale);
Value *Cnt = IC.Builder.CreateElementCount(
II.getType(), ElementCount::getScalable(NumElts));
Cnt->takeName(&II);
return IC.replaceInstUsesWith(II, Cnt);
}

unsigned MinNumElts = getNumElementsFromSVEPredPattern(Pattern);
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24 changes: 8 additions & 16 deletions llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
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Expand Up @@ -935,12 +935,9 @@ Instruction *InstCombinerImpl::visitTrunc(TruncInst &Trunc) {
Trunc.getFunction()->hasFnAttribute(Attribute::VScaleRange)) {
Attribute Attr =
Trunc.getFunction()->getFnAttribute(Attribute::VScaleRange);
if (std::optional<unsigned> MaxVScale = Attr.getVScaleRangeMax()) {
if (Log2_32(*MaxVScale) < DestWidth) {
Value *VScale = Builder.CreateVScale(ConstantInt::get(DestTy, 1));
return replaceInstUsesWith(Trunc, VScale);
}
}
if (std::optional<unsigned> MaxVScale = Attr.getVScaleRangeMax())
if (Log2_32(*MaxVScale) < DestWidth)
return replaceInstUsesWith(Trunc, Builder.CreateVScale(DestTy));
}
}

Expand Down Expand Up @@ -1314,10 +1311,8 @@ Instruction *InstCombinerImpl::visitZExt(ZExtInst &Zext) {
Zext.getFunction()->getFnAttribute(Attribute::VScaleRange);
if (std::optional<unsigned> MaxVScale = Attr.getVScaleRangeMax()) {
unsigned TypeWidth = Src->getType()->getScalarSizeInBits();
if (Log2_32(*MaxVScale) < TypeWidth) {
Value *VScale = Builder.CreateVScale(ConstantInt::get(DestTy, 1));
return replaceInstUsesWith(Zext, VScale);
}
if (Log2_32(*MaxVScale) < TypeWidth)
return replaceInstUsesWith(Zext, Builder.CreateVScale(DestTy));
}
}
}
Expand Down Expand Up @@ -1604,12 +1599,9 @@ Instruction *InstCombinerImpl::visitSExt(SExtInst &Sext) {
Sext.getFunction()->hasFnAttribute(Attribute::VScaleRange)) {
Attribute Attr =
Sext.getFunction()->getFnAttribute(Attribute::VScaleRange);
if (std::optional<unsigned> MaxVScale = Attr.getVScaleRangeMax()) {
if (Log2_32(*MaxVScale) < (SrcBitSize - 1)) {
Value *VScale = Builder.CreateVScale(ConstantInt::get(DestTy, 1));
return replaceInstUsesWith(Sext, VScale);
}
}
if (std::optional<unsigned> MaxVScale = Attr.getVScaleRangeMax())
if (Log2_32(*MaxVScale) < (SrcBitSize - 1))
return replaceInstUsesWith(Sext, Builder.CreateVScale(DestTy));
}
}

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16 changes: 3 additions & 13 deletions llvm/lib/Transforms/Utils/LowerVectorIntrinsics.cpp
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Expand Up @@ -21,29 +21,19 @@ bool llvm::lowerUnaryVectorIntrinsicAsLoop(Module &M, CallInst *CI) {
BasicBlock *PostLoopBB = nullptr;
Function *ParentFunc = PreLoopBB->getParent();
LLVMContext &Ctx = PreLoopBB->getContext();
Type *Int64Ty = IntegerType::get(Ctx, 64);

PostLoopBB = PreLoopBB->splitBasicBlock(CI);
BasicBlock *LoopBB = BasicBlock::Create(Ctx, "", ParentFunc, PostLoopBB);
PreLoopBB->getTerminator()->setSuccessor(0, LoopBB);

// Loop preheader
IRBuilder<> PreLoopBuilder(PreLoopBB->getTerminator());
Value *LoopEnd = nullptr;
if (auto *ScalableVecTy = dyn_cast<ScalableVectorType>(VecTy)) {
Value *VScale = PreLoopBuilder.CreateVScale(
ConstantInt::get(PreLoopBuilder.getInt64Ty(), 1));
Value *N = ConstantInt::get(PreLoopBuilder.getInt64Ty(),
ScalableVecTy->getMinNumElements());
LoopEnd = PreLoopBuilder.CreateMul(VScale, N);
} else {
FixedVectorType *FixedVecTy = cast<FixedVectorType>(VecTy);
LoopEnd = ConstantInt::get(PreLoopBuilder.getInt64Ty(),
FixedVecTy->getNumElements());
}
Value *LoopEnd =
PreLoopBuilder.CreateElementCount(Int64Ty, VecTy->getElementCount());

// Loop body
IRBuilder<> LoopBuilder(LoopBB);
Type *Int64Ty = LoopBuilder.getInt64Ty();

PHINode *LoopIndex = LoopBuilder.CreatePHI(Int64Ty, 2);
LoopIndex->addIncoming(ConstantInt::get(Int64Ty, 0U), PreLoopBB);
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2 changes: 1 addition & 1 deletion llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
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Expand Up @@ -1440,7 +1440,7 @@ Value *SCEVExpander::visitSequentialUMinExpr(const SCEVSequentialUMinExpr *S) {
}

Value *SCEVExpander::visitVScale(const SCEVVScale *S) {
return Builder.CreateVScale(ConstantInt::get(S->getType(), 1));
return Builder.CreateVScale(S->getType());
}

Value *SCEVExpander::expandCodeFor(const SCEV *SH, Type *Ty,
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2 changes: 1 addition & 1 deletion llvm/lib/Transforms/Vectorize/LoopIdiomVectorize.cpp
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Expand Up @@ -437,7 +437,7 @@ Value *LoopIdiomVectorize::createMaskedFindMismatch(
Value *InitialPred = Builder.CreateIntrinsic(
Intrinsic::get_active_lane_mask, {PredVTy, I64Type}, {ExtStart, ExtEnd});

Value *VecLen = Builder.CreateIntrinsic(Intrinsic::vscale, {I64Type}, {});
Value *VecLen = Builder.CreateVScale(I64Type);
VecLen =
Builder.CreateMul(VecLen, ConstantInt::get(I64Type, ByteCompareVF), "",
/*HasNUW=*/true, /*HasNSW=*/true);
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8 changes: 0 additions & 8 deletions llvm/unittests/IR/IRBuilderTest.cpp
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Expand Up @@ -212,14 +212,6 @@ TEST_F(IRBuilderTest, IntrinsicsWithScalableVectors) {
EXPECT_EQ(FTy->getParamType(i), Args[i]->getType());
}

TEST_F(IRBuilderTest, CreateVScale) {
IRBuilder<> Builder(BB);

Constant *Zero = Builder.getInt32(0);
Value *VScale = Builder.CreateVScale(Zero);
EXPECT_TRUE(isa<ConstantInt>(VScale) && cast<ConstantInt>(VScale)->isZero());
}

TEST_F(IRBuilderTest, CreateStepVector) {
IRBuilder<> Builder(BB);

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