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[DA] Fix crash when two loops have different type sizes of becount #165021

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Merged
merged 2 commits into from
Oct 27, 2025
Merged

[DA] Fix crash when two loops have different type sizes of becount #165021

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8894074
[DA] Fix for different sizes of loop becount types in haveSameSD
Oct 24, 2025
8f2a40d
Use SE.getWiderType&getNoopOrZeroExtend per Florian's suggestion
Oct 27, 2025
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11 changes: 8 additions & 3 deletions llvm/lib/Analysis/DependenceAnalysis.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1131,9 +1131,14 @@ bool DependenceInfo::haveSameSD(const Loop *SrcLoop,
if (SE->hasLoopInvariantBackedgeTakenCount(DstLoop))
DstUP = SE->getBackedgeTakenCount(DstLoop);

if (SrcUB != nullptr && DstUP != nullptr &&
SE->isKnownPredicate(ICmpInst::ICMP_EQ, SrcUB, DstUP))
return true;
if (SrcUB != nullptr && DstUP != nullptr) {
Type *WiderType = SE->getWiderType(SrcUB->getType(), DstUP->getType());
SrcUB = SE->getNoopOrZeroExtend(SrcUB, WiderType);
DstUP = SE->getNoopOrZeroExtend(DstUP, WiderType);

if (SE->isKnownPredicate(ICmpInst::ICMP_EQ, SrcUB, DstUP))
return true;
}

return false;
}
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68 changes: 68 additions & 0 deletions llvm/test/Analysis/DependenceAnalysis/same-sd-for-diff-becount-type-loops.ll
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@@ -0,0 +1,68 @@
; RUN: opt < %s -disable-output "-passes=print<da>" -aa-pipeline=basic-aa 2>&1 | FileCheck %s

define void @f1() {
; CHECK-LABEL: 'f1'
; CHECK-NEXT: Src: store i32 0, ptr null, align 4 --> Dst: store i32 0, ptr null, align 4
; CHECK-NEXT: da analyze - consistent output [S]!
; CHECK-NEXT: Src: store i32 0, ptr null, align 4 --> Dst: %2 = load i32, ptr null, align 4
; CHECK-NEXT: da analyze - consistent flow [|<]!
; CHECK-NEXT: Src: %2 = load i32, ptr null, align 4 --> Dst: %2 = load i32, ptr null, align 4
; CHECK-NEXT: da analyze - consistent input [S]!
;
entry:
br label %for.1.header

for.1.header: ; preds = %for.2.end, %entry
br label %for.1.body

for.1.body: ; preds = %for.1.body, %whiledo
%0 = phi i32 [ 0, %for.1.header ], [ 1, %for.1.body ]
store i32 0, ptr null, align 4
%1 = icmp ult i32 %0, 1
br i1 %1, label %for.1.body, label %for.1.end

for.1.end: ; preds = %for.1.body
br label %for.2.body

for.2.body: ; preds = %for.2.body, %for.1.end
%2 = load i32, ptr null, align 4
br i1 false, label %for.2.body, label %exit

exit: ; preds = %for.2.body
ret void
}

define void @f2() {
; CHECK-LABEL: 'f2'
; CHECK-NEXT: Src: store i32 0, ptr null, align 4 --> Dst: store i32 0, ptr null, align 4
; CHECK-NEXT: da analyze - consistent output [S]!
; CHECK-NEXT: Src: store i32 0, ptr null, align 4 --> Dst: %3 = load i32, ptr null, align 4
; CHECK-NEXT: da analyze - flow [|<] / assuming 1 loop level(s) fused: [S|<]!
; CHECK-NEXT: Src: %3 = load i32, ptr null, align 4 --> Dst: %3 = load i32, ptr null, align 4
; CHECK-NEXT: da analyze - consistent input [S]!
;
entry:
br label %for.1.header

for.1.header: ; preds = %for.2.end, %entry
br label %for.1.body

for.1.body: ; preds = %for.1.body, %whiledo
%0 = phi i32 [ 0, %for.1.header ], [ 1, %for.1.body ]
store i32 0, ptr null, align 4
%1 = icmp ult i32 %0, 1
br i1 %1, label %for.1.body, label %for.1.end

for.1.end: ; preds = %for.1.body
br label %for.2.body

for.2.body: ; preds = %for.2.body, %for.1.end
%2 = phi i64 [ 0, %for.1.end ], [ %4, %for.2.body ]
%3 = load i32, ptr null, align 4
%4 = add nuw nsw i64 %2, 1
%5 = icmp ult i64 %4, 2
br i1 %5, label %for.2.body, label %exit

exit: ; preds = %for.2.body
ret void
}