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[SandboxVec][BottomUpVec] Clean up dead instructions #115267

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Merged
merged 1 commit into from
Nov 8, 2024
Merged

[SandboxVec][BottomUpVec] Clean up dead instructions #115267

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2 changes: 2 additions & 0 deletions llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/Passes/BottomUpVec.h
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Original file line number Diff line number Diff line change
Expand Up @@ -25,10 +25,12 @@ namespace llvm::sandboxir {
class BottomUpVec final : public FunctionPass {
bool Change = false;
std::unique_ptr<LegalityAnalysis> Legality;
SmallVector<Instruction *> DeadInstrCandidates;

/// Creates and returns a vector instruction that replaces the instructions in
/// \p Bndl. \p Operands are the already vectorized operands.
Value *createVectorInstr(ArrayRef<Value *> Bndl, ArrayRef<Value *> Operands);
void tryEraseDeadInstrs();
Value *vectorizeRec(ArrayRef<Value *> Bndl);
bool tryVectorize(ArrayRef<Value *> Seeds);

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19 changes: 18 additions & 1 deletion llvm/lib/Transforms/Vectorize/SandboxVectorizer/Passes/BottomUpVec.cpp
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Expand Up @@ -153,6 +153,17 @@ Value *BottomUpVec::createVectorInstr(ArrayRef<Value *> Bndl,
// TODO: Propagate debug info.
}

void BottomUpVec::tryEraseDeadInstrs() {
// Visiting the dead instructions bottom-to-top.
sort(DeadInstrCandidates,
[](Instruction *I1, Instruction *I2) { return I1->comesBefore(I2); });
for (Instruction *I : reverse(DeadInstrCandidates)) {
if (I->hasNUses(0))
I->eraseFromParent();
}
DeadInstrCandidates.clear();
}

Value *BottomUpVec::vectorizeRec(ArrayRef<Value *> Bndl) {
Value *NewVec = nullptr;
const auto &LegalityRes = Legality->canVectorize(Bndl);
Expand Down Expand Up @@ -182,7 +193,11 @@ Value *BottomUpVec::vectorizeRec(ArrayRef<Value *> Bndl) {
}
NewVec = createVectorInstr(Bndl, VecOperands);

// TODO: Collect potentially dead instructions.
// Collect the original scalar instructions as they may be dead.
if (NewVec != nullptr) {
for (Value *V : Bndl)
DeadInstrCandidates.push_back(cast<Instruction>(V));
}
break;
}
case LegalityResultID::Pack: {
Expand All @@ -194,7 +209,9 @@ Value *BottomUpVec::vectorizeRec(ArrayRef<Value *> Bndl) {
}

bool BottomUpVec::tryVectorize(ArrayRef<Value *> Bndl) {
DeadInstrCandidates.clear();
vectorizeRec(Bndl);
tryEraseDeadInstrs();
return Change;
}

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56 changes: 22 additions & 34 deletions llvm/test/Transforms/SandboxVectorizer/bottomup_basic.ll
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Expand Up @@ -6,11 +6,7 @@ define void @store_load(ptr %ptr) {
; CHECK-SAME: ptr [[PTR:%.*]]) {
; CHECK-NEXT: [[PTR0:%.*]] = getelementptr float, ptr [[PTR]], i32 0
; CHECK-NEXT: [[PTR1:%.*]] = getelementptr float, ptr [[PTR]], i32 1
; CHECK-NEXT: [[LD0:%.*]] = load float, ptr [[PTR0]], align 4
; CHECK-NEXT: [[LD1:%.*]] = load float, ptr [[PTR1]], align 4
; CHECK-NEXT: [[VECL:%.*]] = load <2 x float>, ptr [[PTR0]], align 4
; CHECK-NEXT: store float [[LD0]], ptr [[PTR0]], align 4
; CHECK-NEXT: store float [[LD1]], ptr [[PTR1]], align 4
; CHECK-NEXT: store <2 x float> [[VECL]], ptr [[PTR0]], align 4
; CHECK-NEXT: ret void
;
Expand All @@ -31,14 +27,8 @@ define void @store_fpext_load(ptr %ptr) {
; CHECK-NEXT: [[PTR1:%.*]] = getelementptr float, ptr [[PTR]], i32 1
; CHECK-NEXT: [[PTRD0:%.*]] = getelementptr double, ptr [[PTR]], i32 0
; CHECK-NEXT: [[PTRD1:%.*]] = getelementptr double, ptr [[PTR]], i32 1
; CHECK-NEXT: [[LD0:%.*]] = load float, ptr [[PTR0]], align 4
; CHECK-NEXT: [[LD1:%.*]] = load float, ptr [[PTR1]], align 4
; CHECK-NEXT: [[VECL:%.*]] = load <2 x float>, ptr [[PTR0]], align 4
; CHECK-NEXT: [[FPEXT0:%.*]] = fpext float [[LD0]] to double
; CHECK-NEXT: [[FPEXT1:%.*]] = fpext float [[LD1]] to double
; CHECK-NEXT: [[VCAST:%.*]] = fpext <2 x float> [[VECL]] to <2 x double>
; CHECK-NEXT: store double [[FPEXT0]], ptr [[PTRD0]], align 8
; CHECK-NEXT: store double [[FPEXT1]], ptr [[PTRD1]], align 8
; CHECK-NEXT: store <2 x double> [[VCAST]], ptr [[PTRD0]], align 8
; CHECK-NEXT: ret void
;
Expand All @@ -62,20 +52,10 @@ define void @store_fcmp_zext_load(ptr %ptr) {
; CHECK-NEXT: [[PTR1:%.*]] = getelementptr float, ptr [[PTR]], i32 1
; CHECK-NEXT: [[PTRB0:%.*]] = getelementptr i32, ptr [[PTR]], i32 0
; CHECK-NEXT: [[PTRB1:%.*]] = getelementptr i32, ptr [[PTR]], i32 1
; CHECK-NEXT: [[LDB0:%.*]] = load float, ptr [[PTR0]], align 4
; CHECK-NEXT: [[LDB1:%.*]] = load float, ptr [[PTR1]], align 4
; CHECK-NEXT: [[VECL1:%.*]] = load <2 x float>, ptr [[PTR0]], align 4
; CHECK-NEXT: [[LDA0:%.*]] = load float, ptr [[PTR0]], align 4
; CHECK-NEXT: [[LDA1:%.*]] = load float, ptr [[PTR1]], align 4
; CHECK-NEXT: [[VECL:%.*]] = load <2 x float>, ptr [[PTR0]], align 4
; CHECK-NEXT: [[FCMP0:%.*]] = fcmp ogt float [[LDA0]], [[LDB0]]
; CHECK-NEXT: [[FCMP1:%.*]] = fcmp ogt float [[LDA1]], [[LDB1]]
; CHECK-NEXT: [[VCMP:%.*]] = fcmp ogt <2 x float> [[VECL]], [[VECL1]]
; CHECK-NEXT: [[ZEXT0:%.*]] = zext i1 [[FCMP0]] to i32
; CHECK-NEXT: [[ZEXT1:%.*]] = zext i1 [[FCMP1]] to i32
; CHECK-NEXT: [[VCAST:%.*]] = zext <2 x i1> [[VCMP]] to <2 x i32>
; CHECK-NEXT: store i32 [[ZEXT0]], ptr [[PTRB0]], align 4
; CHECK-NEXT: store i32 [[ZEXT1]], ptr [[PTRB1]], align 4
; CHECK-NEXT: store <2 x i32> [[VCAST]], ptr [[PTRB0]], align 4
; CHECK-NEXT: ret void
;
Expand All @@ -101,17 +81,9 @@ define void @store_fadd_load(ptr %ptr) {
; CHECK-SAME: ptr [[PTR:%.*]]) {
; CHECK-NEXT: [[PTR0:%.*]] = getelementptr float, ptr [[PTR]], i32 0
; CHECK-NEXT: [[PTR1:%.*]] = getelementptr float, ptr [[PTR]], i32 1
; CHECK-NEXT: [[LDA0:%.*]] = load float, ptr [[PTR0]], align 4
; CHECK-NEXT: [[LDA1:%.*]] = load float, ptr [[PTR1]], align 4
; CHECK-NEXT: [[VECL:%.*]] = load <2 x float>, ptr [[PTR0]], align 4
; CHECK-NEXT: [[LDB0:%.*]] = load float, ptr [[PTR0]], align 4
; CHECK-NEXT: [[LDB1:%.*]] = load float, ptr [[PTR1]], align 4
; CHECK-NEXT: [[VECL1:%.*]] = load <2 x float>, ptr [[PTR0]], align 4
; CHECK-NEXT: [[FADD0:%.*]] = fadd float [[LDA0]], [[LDB0]]
; CHECK-NEXT: [[FADD1:%.*]] = fadd float [[LDA1]], [[LDB1]]
; CHECK-NEXT: [[VEC:%.*]] = fadd <2 x float> [[VECL]], [[VECL1]]
; CHECK-NEXT: store float [[FADD0]], ptr [[PTR0]], align 4
; CHECK-NEXT: store float [[FADD1]], ptr [[PTR1]], align 4
; CHECK-NEXT: store <2 x float> [[VEC]], ptr [[PTR0]], align 4
; CHECK-NEXT: ret void
;
Expand All @@ -133,14 +105,8 @@ define void @store_fneg_load(ptr %ptr) {
; CHECK-SAME: ptr [[PTR:%.*]]) {
; CHECK-NEXT: [[PTR0:%.*]] = getelementptr float, ptr [[PTR]], i32 0
; CHECK-NEXT: [[PTR1:%.*]] = getelementptr float, ptr [[PTR]], i32 1
; CHECK-NEXT: [[LD0:%.*]] = load float, ptr [[PTR0]], align 4
; CHECK-NEXT: [[LD1:%.*]] = load float, ptr [[PTR1]], align 4
; CHECK-NEXT: [[VECL:%.*]] = load <2 x float>, ptr [[PTR0]], align 4
; CHECK-NEXT: [[FNEG0:%.*]] = fneg float [[LD0]]
; CHECK-NEXT: [[FNEG1:%.*]] = fneg float [[LD1]]
; CHECK-NEXT: [[VEC:%.*]] = fneg <2 x float> [[VECL]]
; CHECK-NEXT: store float [[FNEG0]], ptr [[PTR0]], align 4
; CHECK-NEXT: store float [[FNEG1]], ptr [[PTR1]], align 4
; CHECK-NEXT: store <2 x float> [[VEC]], ptr [[PTR0]], align 4
; CHECK-NEXT: ret void
;
Expand All @@ -155,3 +121,25 @@ define void @store_fneg_load(ptr %ptr) {
ret void
}

define float @scalars_with_external_uses_not_dead(ptr %ptr) {
; CHECK-LABEL: define float @scalars_with_external_uses_not_dead(
; CHECK-SAME: ptr [[PTR:%.*]]) {
; CHECK-NEXT: [[PTR0:%.*]] = getelementptr float, ptr [[PTR]], i32 0
; CHECK-NEXT: [[PTR1:%.*]] = getelementptr float, ptr [[PTR]], i32 1
; CHECK-NEXT: [[LD0:%.*]] = load float, ptr [[PTR0]], align 4
; CHECK-NEXT: [[LD1:%.*]] = load float, ptr [[PTR1]], align 4
; CHECK-NEXT: [[VECL:%.*]] = load <2 x float>, ptr [[PTR0]], align 4
; CHECK-NEXT: store <2 x float> [[VECL]], ptr [[PTR0]], align 4
; CHECK-NEXT: [[USER:%.*]] = fneg float [[LD1]]
; CHECK-NEXT: ret float [[LD0]]
;
%ptr0 = getelementptr float, ptr %ptr, i32 0
%ptr1 = getelementptr float, ptr %ptr, i32 1
%ld0 = load float, ptr %ptr0
%ld1 = load float, ptr %ptr1
store float %ld0, ptr %ptr0
store float %ld1, ptr %ptr1
%user = fneg float %ld1
ret float %ld0
}

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