e73b85d1ab
Summary: SpeculativelyExecuteBB can flatten the CFG by doing speculative execution followed by a select instruction. When the speculatively executed BB contained dbg intrinsics the result could be a little bit weird, since those dbg intrinsics were inserted before the select in the flattened CFG. So when single stepping in the debugger, printing the value of the variable referenced in the dbg intrinsic, it could happen that it looked like the variable had values that never actually were assigned to the variable. This patch simply discards all dbg intrinsics that were found in the speculatively executed BB. Reviewers: aprantl, chandlerc, craig.topper Reviewed By: aprantl Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D39494 llvm-svn: 317198
84 lines
4.1 KiB
LLVM
84 lines
4.1 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -S -simplifycfg | FileCheck %s
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; This test case was generated from speculate-dbgvalue.c:
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;
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; int test1(int getdirt, int dirt) {
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; int result = 100;
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; if (getdirt != 0)
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; result = dirt;
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; return result;
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; }
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;
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; using
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; clang speculate-dbgvalue.c -S -emit-llvm -g -O3 -mllvm -disable-llvm-optzns -o - | opt -mem2reg -S
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; Function Attrs: nounwind uwtable
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define i32 @test1(i32 %getdirt, i32 %dirt) #0 !dbg !7 {
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; CHECK-LABEL: @test1(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: call void @llvm.dbg.value(metadata i32 [[GETDIRT:%.*]], metadata !12, metadata !DIExpression()), !dbg !15
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; CHECK-NEXT: call void @llvm.dbg.value(metadata i32 [[DIRT:%.*]], metadata !13, metadata !DIExpression()), !dbg !16
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; CHECK-NEXT: call void @llvm.dbg.value(metadata i32 100, metadata !14, metadata !DIExpression()), !dbg !17
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; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[GETDIRT]], 0, !dbg !18
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; *** We used to get an incorrect "call void @llvm.dbg.value(metadata i32 [[DIRT]], metadata !14, metadata !DIExpression()), !dbg !17" here, before the select. ***
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; CHECK-NOT: call void @llvm.dbg.value(metadata i32 [[DIRT]], metadata !14
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; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[CMP]], i32 [[DIRT]], i32 100, !dbg !20
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; CHECK-NEXT: call void @llvm.dbg.value(metadata i32 [[RESULT]], metadata !14, metadata !DIExpression()), !dbg !17
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; CHECK-NEXT: ret i32 [[RESULT]], !dbg !21
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; CHECK: !12 = !DILocalVariable(name: "getdirt"
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; CHECK: !13 = !DILocalVariable(name: "dirt"
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; CHECK: !14 = !DILocalVariable(name: "result"
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;
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entry:
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call void @llvm.dbg.value(metadata i32 %getdirt, metadata !12, metadata !DIExpression()), !dbg !15
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call void @llvm.dbg.value(metadata i32 %dirt, metadata !13, metadata !DIExpression()), !dbg !16
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call void @llvm.dbg.value(metadata i32 100, metadata !14, metadata !DIExpression()), !dbg !17
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%cmp = icmp ne i32 %getdirt, 0, !dbg !18
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br i1 %cmp, label %if.then, label %if.end, !dbg !20
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if.then: ; preds = %entry
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call void @llvm.dbg.value(metadata i32 %dirt, metadata !14, metadata !DIExpression()), !dbg !17
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br label %if.end, !dbg !21
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if.end: ; preds = %if.then, %entry
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%result.0 = phi i32 [ %dirt, %if.then ], [ 100, %entry ]
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call void @llvm.dbg.value(metadata i32 %result.0, metadata !14, metadata !DIExpression()), !dbg !17
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ret i32 %result.0, !dbg !22
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}
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; Function Attrs: nounwind readnone speculatable
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declare void @llvm.dbg.value(metadata, metadata, metadata) #1
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attributes #0 = { nounwind uwtable }
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attributes #1 = { nounwind readnone speculatable }
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!3, !4, !5}
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!llvm.ident = !{!6}
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!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 6.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
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!1 = !DIFile(filename: "speculate-dbgvalue.c", directory: "/foo")
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!2 = !{}
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!3 = !{i32 2, !"Dwarf Version", i32 4}
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!4 = !{i32 2, !"Debug Info Version", i32 3}
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!5 = !{i32 1, !"wchar_size", i32 4}
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!6 = !{!"clang version 6.0.0"}
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!7 = distinct !DISubprogram(name: "test1", scope: !1, file: !1, line: 1, type: !8, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !11)
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!8 = !DISubroutineType(types: !9)
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!9 = !{!10, !10, !10}
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!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!11 = !{!12, !13, !14}
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!12 = !DILocalVariable(name: "getdirt", arg: 1, scope: !7, file: !1, line: 1, type: !10)
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!13 = !DILocalVariable(name: "dirt", arg: 2, scope: !7, file: !1, line: 1, type: !10)
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!14 = !DILocalVariable(name: "result", scope: !7, file: !1, line: 2, type: !10)
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!15 = !DILocation(line: 1, column: 15, scope: !7)
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!16 = !DILocation(line: 1, column: 28, scope: !7)
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!17 = !DILocation(line: 2, column: 7, scope: !7)
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!18 = !DILocation(line: 3, column: 15, scope: !19)
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!19 = distinct !DILexicalBlock(scope: !7, file: !1, line: 3, column: 7)
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!20 = !DILocation(line: 3, column: 7, scope: !7)
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!21 = !DILocation(line: 4, column: 5, scope: !19)
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!22 = !DILocation(line: 5, column: 3, scope: !7)
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