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[NewGVN] Remove returned arg simplification #161865

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Merged
merged 2 commits into from
Oct 3, 2025
Merged

[NewGVN] Remove returned arg simplification #161865

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354af47
[NewGVN] Don't use returned arg in memory defining intrinsics
ManuelJBrito Oct 3, 2025
c587292
Update NewGVN.cpp
ManuelJBrito Oct 3, 2025
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4 changes: 0 additions & 4 deletions llvm/lib/Transforms/Scalar/NewGVN.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1646,10 +1646,6 @@ NewGVN::performSymbolicPredicateInfoEvaluation(BitCastInst *I) const {
// Evaluate read only and pure calls, and create an expression result.
NewGVN::ExprResult NewGVN::performSymbolicCallEvaluation(Instruction *I) const {
auto *CI = cast<CallInst>(I);
if (auto *II = dyn_cast<IntrinsicInst>(I)) {
if (auto *ReturnedValue = II->getReturnedArgOperand())
return ExprResult::some(createVariableOrConstant(ReturnedValue));
}

// FIXME: Currently the calls which may access the thread id may
// be considered as not accessing the memory. But this is
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21 changes: 21 additions & 0 deletions llvm/test/Transforms/NewGVN/pr159918.ll
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@@ -0,0 +1,21 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
; RUN: opt -S -passes=newgvn < %s | FileCheck %s

; Don't use returned argument in memory defining intrinsics.
define void @wombat(ptr %arg) {
; CHECK-LABEL: define void @wombat(
; CHECK-SAME: ptr [[ARG:%.*]]) {
; CHECK-NEXT: [[LOAD:%.*]] = load ptr, ptr [[ARG]], align 8
; CHECK-NEXT: [[CALL:%.*]] = call ptr @llvm.objc.retain(ptr [[LOAD]])
; CHECK-NEXT: store ptr [[CALL]], ptr [[ARG]], align 8
; CHECK-NEXT: ret void
;
%load = load ptr, ptr %arg, align 8
%call = call ptr @llvm.objc.retain(ptr %load)
store ptr %call, ptr %arg, align 8
ret void
}

declare ptr @llvm.objc.retain(ptr returned) #0

attributes #0 = { nounwind }