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[BasicAA] Remove NSW flags when merging scales #69122

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Merged
merged 1 commit into from
Oct 15, 2023
Merged

[BasicAA] Remove NSW flags when merging scales #69122

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1 change: 1 addition & 0 deletions llvm/lib/Analysis/BasicAliasAnalysis.cpp
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Expand Up @@ -662,6 +662,7 @@ BasicAAResult::DecomposeGEPExpression(const Value *V, const DataLayout &DL,
if (Decomposed.VarIndices[i].Val.V == LE.Val.V &&
Decomposed.VarIndices[i].Val.hasSameCastsAs(LE.Val)) {
Scale += Decomposed.VarIndices[i].Scale;
LE.IsNSW = false; // We cannot guarantee nsw for the merge.
Decomposed.VarIndices.erase(Decomposed.VarIndices.begin() + i);
break;
}
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4 changes: 2 additions & 2 deletions llvm/test/Analysis/BasicAA/pr69096.ll
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Expand Up @@ -3,8 +3,8 @@
target datalayout = "p:64:64:64"

; CHECK-LABEL: Function: pr69096
; FIXME: This should be MayAlias. %p == %scevgep.i when %a == -1.
; CHECK: NoAlias: i8* %p, i16* %scevgep.i
; %p == %scevgep.i when %a == -1.
; CHECK: MayAlias: i8* %p, i16* %scevgep.i

define i32 @pr69096(i16 %a, ptr %p) {
entry:
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