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[AST] Fix size merging for MustAlias sets #73820

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Merged
merged 1 commit into from
Dec 7, 2023
Merged

[AST] Fix size merging for MustAlias sets #73820

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10 changes: 9 additions & 1 deletion llvm/lib/Analysis/AliasSetTracker.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -348,8 +348,16 @@ AliasSet &AliasSetTracker::getAliasSetFor(const MemoryLocation &MemLoc) {
// due to a quirk of alias analysis behavior. Since alias(undef, undef)
// is NoAlias, mergeAliasSetsForPointer(undef, ...) will not find the
// the right set for undef, even if it exists.
if (Entry.updateSizeAndAAInfo(Size, AAInfo))
if (Entry.updateSizeAndAAInfo(Size, AAInfo)) {
mergeAliasSetsForPointer(Pointer, Size, AAInfo, MustAliasAll);

// For MustAlias sets, also update Size/AAInfo of the representative
// pointer.
AliasSet &AS = *Entry.getAliasSet(*this);
if (AS.isMustAlias())
if (AliasSet::PointerRec *P = AS.getSomePointer())
P->updateSizeAndAAInfo(Size, AAInfo);
}
// Return the set!
return *Entry.getAliasSet(*this)->getForwardedTarget(*this);
}
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8 changes: 3 additions & 5 deletions llvm/test/Transforms/LICM/pr64897.ll
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Original file line number Diff line number Diff line change
@@ -1,7 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
; RUN: opt -S -passes=licm < %s | FileCheck %s

; FIXME: This is a miscompile.
define void @test(i1 %c, i8 %x) {
; CHECK-LABEL: define void @test(
; CHECK-SAME: i1 [[C:%.*]], i8 [[X:%.*]]) {
Expand All @@ -10,17 +9,16 @@ define void @test(i1 %c, i8 %x) {
; CHECK-NEXT: [[P:%.*]] = getelementptr inbounds i8, ptr [[A]], i64 8
; CHECK-NEXT: [[P_COPY:%.*]] = getelementptr inbounds i8, ptr [[A]], i64 8
; CHECK-NEXT: [[P2:%.*]] = getelementptr inbounds i8, ptr [[A]], i64 12
; CHECK-NEXT: [[P2_PROMOTED:%.*]] = load i8, ptr [[P2]], align 1
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[TMP0:%.*]] = phi i8 [ 0, [[LOOP]] ], [ [[P2_PROMOTED]], [[START:%.*]] ]
; CHECK-NEXT: store i32 286331153, ptr [[P]], align 4
; CHECK-NEXT: store i32 34, ptr [[P_COPY]], align 4
; CHECK-NEXT: store i64 3689348814741910323, ptr [[P_COPY]], align 4
; CHECK-NEXT: call void @use(i8 [[TMP0]])
; CHECK-NEXT: [[VAL:%.*]] = load i8, ptr [[P2]], align 1
; CHECK-NEXT: call void @use(i8 [[VAL]])
; CHECK-NEXT: store i8 0, ptr [[P2]], align 1
; CHECK-NEXT: br i1 [[C]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK: exit:
; CHECK-NEXT: store i8 0, ptr [[P2]], align 1
; CHECK-NEXT: ret void
;
start:
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