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[DebugInfo][GVNSink] Fix #77415: GVNSink fails to optimize LLVM IR with debug info #77602

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Merged
merged 5 commits into from
May 20, 2024
Merged

[DebugInfo][GVNSink] Fix #77415: GVNSink fails to optimize LLVM IR with debug info #77602

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114218d
[GVNSink] Fix #77415: GVNSink fails to optimize LLVM IR with debug info
Apochens Jan 10, 2024
78e8257
[GVNSink] Fix #77415: Remove redundant metadata
Apochens Jan 10, 2024
0ea7153
[GVNSink] Fix #77415: Fix metadata
Apochens Jan 10, 2024
39e5902
refine checks in the test
Apochens May 16, 2024
131405f
test nit
Apochens May 17, 2024
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6 changes: 3 additions & 3 deletions llvm/lib/Transforms/Scalar/GVNSink.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -132,7 +132,7 @@ class LockstepReverseIterator {
ActiveBlocks.remove(BB);
continue;
}
Insts.push_back(BB->getTerminator()->getPrevNode());
Insts.push_back(BB->getTerminator()->getPrevNonDebugInstruction());
}
if (Insts.empty())
Fail = true;
Expand Down Expand Up @@ -168,7 +168,7 @@ class LockstepReverseIterator {
if (Inst == &Inst->getParent()->front())
ActiveBlocks.remove(Inst->getParent());
else
NewInsts.push_back(Inst->getPrevNode());
NewInsts.push_back(Inst->getPrevNonDebugInstruction());
}
if (NewInsts.empty()) {
Fail = true;
Expand Down Expand Up @@ -883,7 +883,7 @@ void GVNSink::sinkLastInstruction(ArrayRef<BasicBlock *> Blocks,
BasicBlock *BBEnd) {
SmallVector<Instruction *, 4> Insts;
for (BasicBlock *BB : Blocks)
Insts.push_back(BB->getTerminator()->getPrevNode());
Insts.push_back(BB->getTerminator()->getPrevNonDebugInstruction());
Instruction *I0 = Insts.front();

SmallVector<Value *, 4> NewOperands;
Expand Down
86 changes: 86 additions & 0 deletions llvm/test/Transforms/GVNSink/sink-ignore-dbg-intrinsics.ll
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@@ -0,0 +1,86 @@
; RUN: opt < %s -passes=gvn-sink -S | FileCheck %s

; Test that GVNSink correctly performs the sink optimization in the presence of debug information

; Function Attrs: noinline nounwind uwtable
define dso_local i32 @fun(i32 noundef %a, i32 noundef %b) #0 !dbg !10 {
entry:
tail call void @llvm.dbg.value(metadata i32 %a, metadata !15, metadata !DIExpression()), !dbg !16
tail call void @llvm.dbg.value(metadata i32 %b, metadata !17, metadata !DIExpression()), !dbg !16
%cmp = icmp sgt i32 %b, 10, !dbg !18
br i1 %cmp, label %if.then, label %if.else, !dbg !20

if.then: ; preds = %entry
%add = add nsw i32 %a, 1, !dbg !21
tail call void @llvm.dbg.value(metadata i32 %add, metadata !23, metadata !DIExpression()), !dbg !24
%xor = xor i32 %add, 1, !dbg !25
tail call void @llvm.dbg.value(metadata i32 %xor, metadata !26, metadata !DIExpression()), !dbg !24
tail call void @llvm.dbg.value(metadata i32 %xor, metadata !27, metadata !DIExpression()), !dbg !16
br label %if.end, !dbg !28

if.else: ; preds = %entry
%add1 = add nsw i32 %b, 1, !dbg !29
tail call void @llvm.dbg.value(metadata i32 %add1, metadata !31, metadata !DIExpression()), !dbg !32
%xor2 = xor i32 %add1, 1, !dbg !33
tail call void @llvm.dbg.value(metadata i32 %xor2, metadata !34, metadata !DIExpression()), !dbg !32
tail call void @llvm.dbg.value(metadata i32 %xor2, metadata !27, metadata !DIExpression()), !dbg !16
br label %if.end

; CHECK-LABEL: if.end:
; CHECK: [[SINK:%.*sink]] = phi i32 [ {{.*}} ], [ {{.*}} ]
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nit: we should have a fixed order here.
maybe swap the PHI operands and see if that passed the check.

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or better use the llvm-project/llvm/utils/update_test_checks.py to update the test

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Thanks! Now the incoming blocks has a fixed order.

; CHECK: [[ADD:%.*]] = add nsw i32 [[SINK]], 1
; CHECK: [[XOR:%.*]] = xor i32 [[ADD]], 1
if.end: ; preds = %if.else, %if.then
%ret.0 = phi i32 [ %xor, %if.then ], [ %xor2, %if.else ], !dbg !35
tail call void @llvm.dbg.value(metadata i32 %ret.0, metadata !27, metadata !DIExpression()), !dbg !16
ret i32 %ret.0, !dbg !36
}

; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
declare void @llvm.dbg.declare(metadata, metadata, metadata) #1

; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
declare void @llvm.dbg.value(metadata, metadata, metadata) #1

attributes #0 = { noinline nounwind uwtable "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #1 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }

!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!2, !3, !4, !5, !6, !7, !8}

!0 = distinct !DICompileUnit(language: DW_LANG_C11, file: !1, producer: "clang version 18.0.0git (https://github.com/llvm/llvm-project.git 5dfcb3e5d1d16bb4f8fce52b3c089119ed977e7f)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)
!1 = !DIFile(filename: "main.c", directory: "/")
!2 = !{i32 7, !"Dwarf Version", i32 5}
!3 = !{i32 2, !"Debug Info Version", i32 3}
!4 = !{i32 1, !"wchar_size", i32 4}
!5 = !{i32 8, !"PIC Level", i32 2}
!6 = !{i32 7, !"PIE Level", i32 2}
!7 = !{i32 7, !"uwtable", i32 2}
!8 = !{i32 7, !"frame-pointer", i32 2}
!10 = distinct !DISubprogram(name: "fun", scope: !1, file: !1, line: 1, type: !11, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !14)
!11 = !DISubroutineType(types: !12)
!12 = !{!13, !13, !13}
!13 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!14 = !{}
!15 = !DILocalVariable(name: "a", arg: 1, scope: !10, file: !1, line: 1, type: !13)
!16 = !DILocation(line: 0, scope: !10)
!17 = !DILocalVariable(name: "b", arg: 2, scope: !10, file: !1, line: 1, type: !13)
!18 = !DILocation(line: 3, column: 11, scope: !19)
!19 = distinct !DILexicalBlock(scope: !10, file: !1, line: 3, column: 9)
!20 = !DILocation(line: 3, column: 9, scope: !10)
!21 = !DILocation(line: 4, column: 20, scope: !22)
!22 = distinct !DILexicalBlock(scope: !19, file: !1, line: 3, column: 17)
!23 = !DILocalVariable(name: "a1", scope: !22, file: !1, line: 4, type: !13)
!24 = !DILocation(line: 0, scope: !22)
!25 = !DILocation(line: 5, column: 21, scope: !22)
!26 = !DILocalVariable(name: "a2", scope: !22, file: !1, line: 5, type: !13)
!27 = !DILocalVariable(name: "ret", scope: !10, file: !1, line: 2, type: !13)
!28 = !DILocation(line: 7, column: 5, scope: !22)
!29 = !DILocation(line: 8, column: 20, scope: !30)
!30 = distinct !DILexicalBlock(scope: !19, file: !1, line: 7, column: 12)
!31 = !DILocalVariable(name: "b1", scope: !30, file: !1, line: 8, type: !13)
!32 = !DILocation(line: 0, scope: !30)
!33 = !DILocation(line: 9, column: 21, scope: !30)
!34 = !DILocalVariable(name: "b2", scope: !30, file: !1, line: 9, type: !13)
!35 = !DILocation(line: 0, scope: !19)
!36 = !DILocation(line: 12, column: 5, scope: !10)
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