| ; RUN: opt < %s -S -simplifycfg | FileCheck %s |
| |
| ; When SimplifyCFG changes the PHI node into a select instruction, the debug |
| ; information becomes ambiguous. It causes the debugger to display wrong |
| ; variable value. |
| ; |
| ; When in the debugger, on the line "if (read == 4)", the value of "result" |
| ; is reported as '2', where it should be zero. |
| |
| ; IR generated with: |
| ; clang -S -g -O2 -emit-llvm pr38763.cpp -o pr38763.ll -mllvm -opt-bisect-limit=10 |
| |
| ; // pr38763.cpp |
| ; int main() { |
| ; volatile int foo = 4; |
| ; int read = foo; |
| ; int read1 = foo; |
| ; |
| ; int result = 0; |
| ; if (read == 4) { |
| ; result = read1 + 2; |
| ; } else { |
| ; result = read1 - 2; |
| ; } |
| ; |
| ; return result; |
| ; } |
| |
| ; Remove the '@llvm.dbg.value' associated with 'result' for the true/false |
| ; branches, as they becomes ambiguous. |
| |
| ; CHECK-LABEL: entry |
| ; CHECK: %cmp = icmp eq i32 %foo.0., 4, !dbg !14 |
| ; CHECK: %add = add nsw i32 %foo.0.4, 2, !dbg !16 |
| ; CHECK-NOT: @llvm.dbg.value(metadata i32 %add |
| ; CHECK: %sub = add nsw i32 %foo.0.4, -2, !dbg !16 |
| ; CHECK-NOT: @llvm.dbg.value(metadata i32 %sub |
| ; CHECK: %result.0 = select i1 %cmp, i32 %add, i32 %sub |
| ; CHECK: call void @llvm.dbg.value(metadata i32 %result.0, metadata !12, metadata !DIExpression()), !dbg !13 |
| |
| ; ModuleID = 'pr38763.cpp' |
| source_filename = "pr38763.cpp" |
| target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" |
| target triple = "x86_64-pc-linux-gnu" |
| |
| ; Function Attrs: norecurse nounwind uwtable |
| define dso_local i32 @main() local_unnamed_addr #0 !dbg !7 { |
| entry: |
| %foo = alloca i32, align 4 |
| %foo.0..sroa_cast = bitcast i32* %foo to i8* |
| store volatile i32 4, i32* %foo, align 4 |
| %foo.0. = load volatile i32, i32* %foo, align 4 |
| %foo.0.4 = load volatile i32, i32* %foo, align 4 |
| call void @llvm.dbg.value(metadata i32 0, metadata !16, metadata !DIExpression()), !dbg !27 |
| %cmp = icmp eq i32 %foo.0., 4, !dbg !28 |
| br i1 %cmp, label %if.then, label %if.else, !dbg !30 |
| |
| if.then: ; preds = %entry |
| %add = add nsw i32 %foo.0.4, 2, !dbg !31 |
| call void @llvm.dbg.value(metadata i32 %add, metadata !16, metadata !DIExpression()), !dbg !27 |
| br label %if.end |
| |
| if.else: ; preds = %entry |
| %sub = add nsw i32 %foo.0.4, -2, !dbg !34 |
| call void @llvm.dbg.value(metadata i32 %sub, metadata !16, metadata !DIExpression()), !dbg !27 |
| br label %if.end |
| |
| if.end: ; preds = %if.else, %if.then |
| %result.0 = phi i32 [ %add, %if.then ], [ %sub, %if.else ] |
| call void @llvm.dbg.value(metadata i32 %result.0, metadata !16, metadata !DIExpression()), !dbg !27 |
| ret i32 %result.0 |
| } |
| |
| ; Function Attrs: nounwind readnone speculatable |
| declare void @llvm.dbg.value(metadata, metadata, metadata) #2 |
| |
| !llvm.dbg.cu = !{!0} |
| !llvm.module.flags = !{!3, !4, !5} |
| !llvm.ident = !{!6} |
| |
| !0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 8.0.0 (trunk 342209)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None) |
| !1 = !DIFile(filename: "pr38763.cpp", directory: ".") |
| !2 = !{} |
| !3 = !{i32 2, !"Dwarf Version", i32 4} |
| !4 = !{i32 2, !"Debug Info Version", i32 3} |
| !5 = !{i32 1, !"wchar_size", i32 4} |
| !6 = !{!"clang version 8.0.0 (trunk 342209)"} |
| !7 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 1, type: !8, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: true, unit: !0, retainedNodes: !11) |
| !8 = !DISubroutineType(types: !9) |
| !9 = !{!10} |
| !10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) |
| !11 = !{!16} |
| !16 = !DILocalVariable(name: "result", scope: !7, file: !1, line: 6, type: !10) |
| !27 = !DILocation(line: 6, column: 7, scope: !7) |
| !28 = !DILocation(line: 7, column: 12, scope: !29) |
| !29 = distinct !DILexicalBlock(scope: !7, file: !1, line: 7, column: 7) |
| !30 = !DILocation(line: 7, column: 7, scope: !7) |
| !31 = !DILocation(line: 8, column: 20, scope: !32) |
| !32 = distinct !DILexicalBlock(scope: !29, file: !1, line: 7, column: 18) |
| !34 = !DILocation(line: 10, column: 20, scope: !35) |
| !35 = distinct !DILexicalBlock(scope: !29, file: !1, line: 9, column: 10) |