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[DebugInfo] Salvage debug info when sinking loop invariant instructions
Reviewed By: vsk, aprantl, djtodoro Differential Revision: https://reviews.llvm.org/D77318 (cherry picked from commit 9b56cc9)
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Original file line number | Diff line number | Diff line change |
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; RUN: opt -licm %s -S | FileCheck %s | ||
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; CHECK: for.body: | ||
; CHECK-NEXT: llvm.dbg.value(metadata i8 undef | ||
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; The load is loop invariant. Check that we leave an undef dbg.value behind | ||
; when licm sinks the instruction. | ||
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; clang reduce.cpp -g -O2 -Xclang -disable-llvm-passes -emit-llvm -o reduce.ll | ||
; opt -simplifycfg -sroa -loop-rotate -o - -S reduce.ll | ||
; cat reduce.cpp | ||
; extern char a; | ||
; extern char b; | ||
; void use(char); | ||
; void fun() { | ||
; char local = 0; | ||
; for (;b;) | ||
; local = a; | ||
; use(local); | ||
; } | ||
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@b = external dso_local global i8, align 1 | ||
@a = external dso_local global i8, align 1 | ||
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define dso_local void @_Z3funv() !dbg !12 { | ||
entry: | ||
call void @llvm.dbg.value(metadata i8 0, metadata !16, metadata !DIExpression()), !dbg !17 | ||
%0 = load i8, i8* @b, align 1, !dbg !18 | ||
%tobool1 = icmp ne i8 %0, 0, !dbg !18 | ||
br i1 %tobool1, label %for.body.lr.ph, label %for.end, !dbg !24 | ||
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for.body.lr.ph: ; preds = %entry | ||
br label %for.body, !dbg !24 | ||
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for.body: ; preds = %for.body.lr.ph, %for.body | ||
%1 = load i8, i8* @a, align 1, !dbg !25 | ||
call void @llvm.dbg.value(metadata i8 %1, metadata !16, metadata !DIExpression()), !dbg !17 | ||
%2 = load i8, i8* @b, align 1, !dbg !18 | ||
%tobool = icmp ne i8 %2, 0, !dbg !18 | ||
br i1 %tobool, label %for.body, label %for.cond.for.end_crit_edge, !dbg !24, !llvm.loop !26 | ||
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for.cond.for.end_crit_edge: ; preds = %for.body | ||
%split = phi i8 [ %1, %for.body ] | ||
br label %for.end, !dbg !24 | ||
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for.end: ; preds = %for.cond.for.end_crit_edge, %entry | ||
%local.0.lcssa = phi i8 [ %split, %for.cond.for.end_crit_edge ], [ 0, %entry ], !dbg !17 | ||
call void @llvm.dbg.value(metadata i8 %local.0.lcssa, metadata !16, metadata !DIExpression()), !dbg !17 | ||
call void @_Z3usec(i8 signext %local.0.lcssa), !dbg !28 | ||
ret void, !dbg !29 | ||
} | ||
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declare !dbg !4 dso_local void @_Z3usec(i8 signext) | ||
declare void @llvm.dbg.value(metadata, metadata, metadata) | ||
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!llvm.dbg.cu = !{!0} | ||
!llvm.module.flags = !{!8, !9, !10} | ||
!llvm.ident = !{!11} | ||
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!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 11.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, splitDebugInlining: false, nameTableKind: None) | ||
!1 = !DIFile(filename: "reduce.cpp", directory: "/") | ||
!2 = !{} | ||
!3 = !{!4} | ||
!4 = !DISubprogram(name: "use", linkageName: "_Z3usec", scope: !1, file: !1, line: 3, type: !5, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2) | ||
!5 = !DISubroutineType(types: !6) | ||
!6 = !{null, !7} | ||
!7 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char) | ||
!8 = !{i32 7, !"Dwarf Version", i32 4} | ||
!9 = !{i32 2, !"Debug Info Version", i32 3} | ||
!10 = !{i32 1, !"wchar_size", i32 4} | ||
!11 = !{!"clang version 11.0.0"} | ||
!12 = distinct !DISubprogram(name: "fun", linkageName: "_Z3funv", scope: !1, file: !1, line: 4, type: !13, scopeLine: 4, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !15) | ||
!13 = !DISubroutineType(types: !14) | ||
!14 = !{null} | ||
!15 = !{!16} | ||
!16 = !DILocalVariable(name: "local", scope: !12, file: !1, line: 5, type: !7) | ||
!17 = !DILocation(line: 0, scope: !12) | ||
!18 = !DILocation(line: 6, column: 9, scope: !19) | ||
!19 = distinct !DILexicalBlock(scope: !20, file: !1, line: 6, column: 3) | ||
!20 = distinct !DILexicalBlock(scope: !12, file: !1, line: 6, column: 3) | ||
!24 = !DILocation(line: 6, column: 3, scope: !20) | ||
!25 = !DILocation(line: 7, column: 13, scope: !19) | ||
!26 = distinct !{!26, !24, !27} | ||
!27 = !DILocation(line: 7, column: 13, scope: !20) | ||
!28 = !DILocation(line: 8, column: 3, scope: !12) | ||
!29 = !DILocation(line: 9, column: 1, scope: !12) |