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[SLP]Introduce transformNodes() and transform loads + reverse to strided loads. #88530

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Merged
merged 2 commits into from
Apr 22, 2024
Merged

[SLP]Introduce transformNodes() and transform loads + reverse to strided loads. #88530

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c8e64f3
[𝘀𝗽𝗿] initial version
alexey-bataev Apr 12, 2024
1024405
Rebase
alexey-bataev Apr 16, 2024
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43 changes: 43 additions & 0 deletions llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1126,6 +1126,9 @@ class BoUpSLP {
void
buildExternalUses(const ExtraValueToDebugLocsMap &ExternallyUsedValues = {});

/// Transforms graph nodes to target specific representations, if profitable.
void transformNodes();

/// Clear the internal data structures that are created by 'buildTree'.
void deleteTree() {
VectorizableTree.clear();
Expand Down Expand Up @@ -7813,6 +7816,43 @@ getGEPCosts(const TargetTransformInfo &TTI, ArrayRef<Value *> Ptrs,
return std::make_pair(ScalarCost, VecCost);
}

void BoUpSLP::transformNodes() {
constexpr TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
for (std::unique_ptr<TreeEntry> &TE : VectorizableTree) {
TreeEntry &E = *TE.get();
switch (E.getOpcode()) {
case Instruction::Load: {
Type *ScalarTy = E.getMainOp()->getType();
auto *VecTy = FixedVectorType::get(ScalarTy, E.Scalars.size());
Align CommonAlignment = computeCommonAlignment<LoadInst>(E.Scalars);
// Check if profitable to represent consecutive load + reverse as strided
// load with stride -1.
if (isReverseOrder(E.ReorderIndices) &&
TTI->isLegalStridedLoadStore(VecTy, CommonAlignment)) {
SmallVector<int> Mask;
inversePermutation(E.ReorderIndices, Mask);
auto *BaseLI = cast<LoadInst>(E.Scalars.back());
InstructionCost OriginalVecCost =
TTI->getMemoryOpCost(Instruction::Load, VecTy, BaseLI->getAlign(),
BaseLI->getPointerAddressSpace(), CostKind,
TTI::OperandValueInfo()) +
::getShuffleCost(*TTI, TTI::SK_Reverse, VecTy, Mask, CostKind);
InstructionCost StridedCost = TTI->getStridedMemoryOpCost(
Instruction::Load, VecTy, BaseLI->getPointerOperand(),
/*VariableMask=*/false, CommonAlignment, CostKind, BaseLI);
if (StridedCost < OriginalVecCost)
// Strided load is more profitable than consecutive load + reverse -
// transform the node to strided load.
E.State = TreeEntry::StridedVectorize;
}
break;
}
default:
break;
}
}
}

/// Merges shuffle masks and emits final shuffle instruction, if required. It
/// supports shuffling of 2 input vectors. It implements lazy shuffles emission,
/// when the actual shuffle instruction is generated only if this is actually
Expand Down Expand Up @@ -15135,6 +15175,7 @@ bool SLPVectorizerPass::vectorizeStoreChain(ArrayRef<Value *> Chain, BoUpSLP &R,
R.buildExternalUses();

R.computeMinimumValueSizes();
R.transformNodes();

InstructionCost Cost = R.getTreeCost();

Expand Down Expand Up @@ -15534,6 +15575,7 @@ bool SLPVectorizerPass::tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R,
R.buildExternalUses();

R.computeMinimumValueSizes();
R.transformNodes();
InstructionCost Cost = R.getTreeCost();
CandidateFound = true;
MinCost = std::min(MinCost, Cost);
Expand Down Expand Up @@ -16530,6 +16572,7 @@ class HorizontalReduction {
V.buildExternalUses(LocalExternallyUsedValues);

V.computeMinimumValueSizes();
V.transformNodes();

// Estimate cost.
InstructionCost TreeCost = V.getTreeCost(VL);
Expand Down
5 changes: 2 additions & 3 deletions llvm/test/Transforms/SLPVectorizer/RISCV/strided-loads-vectorized.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -240,11 +240,10 @@ define void @test3(ptr %p, ptr noalias %s) {
; CHECK-LABEL: @test3(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds [48 x float], ptr [[P:%.*]], i64 0, i64 0
; CHECK-NEXT: [[ARRAYIDX1:%.*]] = getelementptr inbounds [48 x float], ptr [[P]], i64 0, i64 30
; CHECK-NEXT: [[ARRAYIDX2:%.*]] = getelementptr inbounds float, ptr [[S:%.*]], i64 0
; CHECK-NEXT: [[ARRAYIDX48:%.*]] = getelementptr inbounds [48 x float], ptr [[P]], i64 0, i64 23
; CHECK-NEXT: [[TMP0:%.*]] = call <8 x float> @llvm.experimental.vp.strided.load.v8f32.p0.i64(ptr align 4 [[ARRAYIDX]], i64 16, <8 x i1> <i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true>, i32 8)
; CHECK-NEXT: [[TMP1:%.*]] = load <8 x float>, ptr [[ARRAYIDX48]], align 4
; CHECK-NEXT: [[TMP2:%.*]] = shufflevector <8 x float> [[TMP1]], <8 x float> poison, <8 x i32> <i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
; CHECK-NEXT: [[TMP2:%.*]] = call <8 x float> @llvm.experimental.vp.strided.load.v8f32.p0.i64(ptr align 4 [[ARRAYIDX1]], i64 -4, <8 x i1> <i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true>, i32 8)
; CHECK-NEXT: [[TMP3:%.*]] = fsub fast <8 x float> [[TMP2]], [[TMP0]]
; CHECK-NEXT: store <8 x float> [[TMP3]], ptr [[ARRAYIDX2]], align 4
; CHECK-NEXT: ret void
Expand Down