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[VectorCombine] Limit scalarization known non-poison indices.

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We can only trust the range of the index if it is guaranteed
non-poison.

Fixes PR50949.

Reviewed By: lebedev.ri

Differential Revision: https://reviews.llvm.org/D107364
This commit is contained in:
Florian Hahn
2021-08-05 14:50:37 +01:00
parent 06206a8cd1
commit 38b098be66
2 changed files with 9 additions and 4 deletions
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3
llvm/lib/Transforms/Vectorize/VectorCombine.cpp
View File

@@ -781,6 +781,9 @@ static bool canScalarizeAccess(FixedVectorType *VecTy, Value *Idx,
if (auto *C = dyn_cast<ConstantInt>(Idx))
return C->getValue().ult(VecTy->getNumElements());
if (!isGuaranteedNotToBePoison(Idx, &AC))
return false;
APInt Zero(Idx->getType()->getScalarSizeInBits(), 0);
APInt MaxElts(Idx->getType()->getScalarSizeInBits(), VecTy->getNumElements());
ConstantRange ValidIndices(Zero, MaxElts);

10
llvm/test/Transforms/VectorCombine/load-insert-store.ll
View File

@@ -310,9 +310,10 @@ entry:
define void @insert_store_nonconst_index_known_valid_by_and_but_may_be_poison(<16 x i8>* %q, i8 zeroext %s, i32 %idx) {
; CHECK-LABEL: @insert_store_nonconst_index_known_valid_by_and_but_may_be_poison(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = load <16 x i8>, <16 x i8>* [[Q:%.*]], align 16
; CHECK-NEXT: [[IDX_CLAMPED:%.*]] = and i32 [[IDX:%.*]], 7
; CHECK-NEXT: [[TMP0:%.*]] = getelementptr inbounds <16 x i8>, <16 x i8>* [[Q:%.*]], i32 0, i32 [[IDX_CLAMPED]]
; CHECK-NEXT: store i8 [[S:%.*]], i8* [[TMP0]], align 1
; CHECK-NEXT: [[VECINS:%.*]] = insertelement <16 x i8> [[TMP0]], i8 [[S:%.*]], i32 [[IDX_CLAMPED]]
; CHECK-NEXT: store <16 x i8> [[VECINS]], <16 x i8>* [[Q]], align 16
; CHECK-NEXT: ret void
;
entry:
@@ -412,9 +413,10 @@ entry:
define void @insert_store_nonconst_index_known_valid_by_urem_but_may_be_poison(<16 x i8>* %q, i8 zeroext %s, i32 %idx) {
; CHECK-LABEL: @insert_store_nonconst_index_known_valid_by_urem_but_may_be_poison(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = load <16 x i8>, <16 x i8>* [[Q:%.*]], align 16
; CHECK-NEXT: [[IDX_CLAMPED:%.*]] = urem i32 [[IDX:%.*]], 16
; CHECK-NEXT: [[TMP0:%.*]] = getelementptr inbounds <16 x i8>, <16 x i8>* [[Q:%.*]], i32 0, i32 [[IDX_CLAMPED]]
; CHECK-NEXT: store i8 [[S:%.*]], i8* [[TMP0]], align 1
; CHECK-NEXT: [[VECINS:%.*]] = insertelement <16 x i8> [[TMP0]], i8 [[S:%.*]], i32 [[IDX_CLAMPED]]
; CHECK-NEXT: store <16 x i8> [[VECINS]], <16 x i8>* [[Q]], align 16
; CHECK-NEXT: ret void
;
entry: