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[SLP]Improve comparison of shuffled loads/masked gathers by adding GEP cost. #90737

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merged 1 commit into from
May 1, 2024
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[SLP]Improve comparison of shuffled loads/masked gathers by adding GEP cost. #90737

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76 changes: 56 additions & 20 deletions llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4326,6 +4326,11 @@ calculateRtStride(ArrayRef<Value *> PointerOps, Type *ElemTy,
return Expander.expandCodeFor(Stride, Stride->getType(), Inst);
}

static std::pair<InstructionCost, InstructionCost>
getGEPCosts(const TargetTransformInfo &TTI, ArrayRef<Value *> Ptrs,
Value *BasePtr, unsigned Opcode, TTI::TargetCostKind CostKind,
Type *ScalarTy, VectorType *VecTy);

BoUpSLP::LoadsState BoUpSLP::canVectorizeLoads(
ArrayRef<Value *> VL, const Value *VL0, SmallVectorImpl<unsigned> &Order,
SmallVectorImpl<Value *> &PointerOps, bool TryRecursiveCheck) const {
Expand Down Expand Up @@ -4464,31 +4469,56 @@ BoUpSLP::LoadsState BoUpSLP::canVectorizeLoads(
if (VectorizedCnt == VL.size() / VF) {
// Compare masked gather cost and loads + insersubvector costs.
TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
InstructionCost MaskedGatherCost = TTI.getGatherScatterOpCost(
Instruction::Load, VecTy,
cast<LoadInst>(VL0)->getPointerOperand(),
/*VariableMask=*/false, CommonAlignment, CostKind);
auto [ScalarGEPCost, VectorGEPCost] = getGEPCosts(
TTI, PointerOps, PointerOps.front(), Instruction::GetElementPtr,
CostKind, ScalarTy, VecTy);
InstructionCost MaskedGatherCost =
TTI.getGatherScatterOpCost(
Instruction::Load, VecTy,
cast<LoadInst>(VL0)->getPointerOperand(),
/*VariableMask=*/false, CommonAlignment, CostKind) +
VectorGEPCost - ScalarGEPCost;
InstructionCost VecLdCost = 0;
auto *SubVecTy = FixedVectorType::get(ScalarTy, VF);
for (auto [I, LS] : enumerate(States)) {
auto *LI0 = cast<LoadInst>(VL[I * VF]);
switch (LS) {
case LoadsState::Vectorize:
case LoadsState::Vectorize: {
auto [ScalarGEPCost, VectorGEPCost] =
getGEPCosts(TTI, ArrayRef(PointerOps).slice(I * VF, VF),
LI0->getPointerOperand(), Instruction::Load,
CostKind, ScalarTy, SubVecTy);
VecLdCost += TTI.getMemoryOpCost(
Instruction::Load, SubVecTy, LI0->getAlign(),
LI0->getPointerAddressSpace(), CostKind,
TTI::OperandValueInfo());
Instruction::Load, SubVecTy, LI0->getAlign(),
LI0->getPointerAddressSpace(), CostKind,
TTI::OperandValueInfo()) +
VectorGEPCost - ScalarGEPCost;
break;
case LoadsState::StridedVectorize:
VecLdCost += TTI.getStridedMemoryOpCost(
Instruction::Load, SubVecTy, LI0->getPointerOperand(),
/*VariableMask=*/false, CommonAlignment, CostKind);
}
case LoadsState::StridedVectorize: {
auto [ScalarGEPCost, VectorGEPCost] =
getGEPCosts(TTI, ArrayRef(PointerOps).slice(I * VF, VF),
LI0->getPointerOperand(), Instruction::Load,
CostKind, ScalarTy, SubVecTy);
VecLdCost +=
TTI.getStridedMemoryOpCost(
Instruction::Load, SubVecTy, LI0->getPointerOperand(),
/*VariableMask=*/false, CommonAlignment, CostKind) +
VectorGEPCost - ScalarGEPCost;
break;
case LoadsState::ScatterVectorize:
VecLdCost += TTI.getGatherScatterOpCost(
Instruction::Load, SubVecTy, LI0->getPointerOperand(),
/*VariableMask=*/false, CommonAlignment, CostKind);
}
case LoadsState::ScatterVectorize: {
auto [ScalarGEPCost, VectorGEPCost] = getGEPCosts(
TTI, ArrayRef(PointerOps).slice(I * VF, VF),
LI0->getPointerOperand(), Instruction::GetElementPtr,
CostKind, ScalarTy, SubVecTy);
VecLdCost +=
TTI.getGatherScatterOpCost(
Instruction::Load, SubVecTy, LI0->getPointerOperand(),
/*VariableMask=*/false, CommonAlignment, CostKind) +
VectorGEPCost - ScalarGEPCost;
break;
}
case LoadsState::Gather:
llvm_unreachable(
"Expected only consecutive, strided or masked gather loads.");
Expand All @@ -4497,13 +4527,13 @@ BoUpSLP::LoadsState BoUpSLP::canVectorizeLoads(
for (int Idx : seq<int>(0, VL.size()))
ShuffleMask[Idx] = Idx / VF == I ? VL.size() + Idx % VF : Idx;
VecLdCost +=
TTI.getShuffleCost(TTI ::SK_InsertSubvector, VecTy,
ShuffleMask, CostKind, I * VF, SubVecTy);
TTI.getShuffleCost(TTI::SK_InsertSubvector, VecTy, ShuffleMask,
CostKind, I * VF, SubVecTy);
}
// If masked gather cost is higher - better to vectorize, so
// consider it as a gather node. It will be better estimated
// later.
if (MaskedGatherCost > VecLdCost)
if (MaskedGatherCost >= VecLdCost)
return true;
}
}
Expand Down Expand Up @@ -7951,7 +7981,13 @@ getGEPCosts(const TargetTransformInfo &TTI, ArrayRef<Value *> Ptrs,

ScalarCost =
TTI.getPointersChainCost(Ptrs, BasePtr, PtrsInfo, ScalarTy, CostKind);
if (auto *BaseGEP = dyn_cast<GEPOperator>(BasePtr)) {
auto *BaseGEP = dyn_cast<GEPOperator>(BasePtr);
if (!BaseGEP) {
auto *It = find_if(Ptrs, IsaPred<GEPOperator>);
if (It != Ptrs.end())
BaseGEP = cast<GEPOperator>(*It);
}
if (BaseGEP) {
SmallVector<const Value *> Indices(BaseGEP->indices());
VecCost = TTI.getGEPCost(BaseGEP->getSourceElementType(),
BaseGEP->getPointerOperand(), Indices, VecTy,
Expand Down
15 changes: 6 additions & 9 deletions llvm/test/Transforms/SLPVectorizer/RISCV/combined-loads-stored.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -4,16 +4,13 @@
define void @test(ptr noalias %p, ptr %p1) {
; CHECK-LABEL: define void @test(
; CHECK-SAME: ptr noalias [[P:%.*]], ptr [[P1:%.*]]) #[[ATTR0:[0-9]+]] {
; CHECK-NEXT: [[GEP799:%.*]] = getelementptr inbounds i8, ptr [[P]], i64 16
; CHECK-NEXT: [[L3:%.*]] = load i16, ptr [[GEP799]], align 2
; CHECK-NEXT: [[GEP3:%.*]] = getelementptr inbounds i8, ptr [[P]], i64 18
; CHECK-NEXT: [[L4:%.*]] = load i16, ptr [[GEP3]], align 2
; CHECK-NEXT: [[TMP1:%.*]] = load <2 x i16>, ptr [[P]], align 2
; CHECK-NEXT: store <2 x i16> [[TMP1]], ptr [[P1]], align 2
; CHECK-NEXT: [[GEPS2:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 4
; CHECK-NEXT: store i16 [[L3]], ptr [[GEPS2]], align 2
; CHECK-NEXT: [[GEPS3:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 6
; CHECK-NEXT: store i16 [[L4]], ptr [[GEPS3]], align 2
; CHECK-NEXT: [[GEP2:%.*]] = getelementptr inbounds i8, ptr [[P]], i64 16
; CHECK-NEXT: [[TMP2:%.*]] = load <2 x i16>, ptr [[GEP2]], align 2
; CHECK-NEXT: [[TMP3:%.*]] = shufflevector <2 x i16> [[TMP1]], <2 x i16> poison, <4 x i32> <i32 0, i32 1, i32 poison, i32 poison>
; CHECK-NEXT: [[TMP4:%.*]] = shufflevector <2 x i16> [[TMP2]], <2 x i16> poison, <4 x i32> <i32 0, i32 1, i32 poison, i32 poison>
; CHECK-NEXT: [[TMP5:%.*]] = shufflevector <4 x i16> [[TMP3]], <4 x i16> [[TMP4]], <4 x i32> <i32 0, i32 1, i32 4, i32 5>
; CHECK-NEXT: store <4 x i16> [[TMP5]], ptr [[P1]], align 2
; CHECK-NEXT: ret void
;
%l1 = load i16, ptr %p, align 2
Expand Down