1; RUN: opt < %s -S -passes=simplifycfg | FileCheck %s 2 3; Note: This patch is a complement to pr38763. 4; 5; When SimplifyCFG changes the PHI node into a select instruction, the debug 6; information becomes ambiguous. It causes the debugger to display unreached 7; lines and invalid variable values. 8; 9; When in the debugger, on the line "if (read1 > 3)", and we step from the 10; 'if' condition, onto the addition, then back to the 'if' again, which is 11; misleading because that addition doesn't really "happen" (it's speculated). 12 13; IR generated with: 14; clang -S -g -gno-column-info -O2 -emit-llvm pr38762.cpp -o pr38762.ll -mllvm -opt-bisect-limit=10 15 16; // pr38762.cpp 17; int main() { 18; volatile int foo = 0; 19; int read1 = foo; 20; int brains = foo; 21; 22; if (read1 > 3) { 23; brains *= 2; 24; brains += 1; 25; } 26; 27; return brains; 28; } 29 30; Change the debug locations associated with the PHI nodes being promoted, to 31; the debug locations from the insertion point in the dominant block. 32 33; CHECK-LABEL: entry 34; CHECK: %cmp = icmp sgt i32 %foo.0., 3, !dbg !14 35; CHECK: %mul = shl nsw i32 %foo.0.5, 1, !dbg !16 36; CHECK-NOT: call void @llvm.dbg.value(metadata i32 %mul, metadata !15, metadata !DIExpression()), !dbg !25 37; CHECK: %add = or i32 %mul, 1, !dbg !16 38; CHECK-NOT: call void @llvm.dbg.value(metadata i32 %add, metadata !15, metadata !DIExpression()), !dbg !25 39; CHECK: %brains.0 = select i1 %cmp, i32 %add, i32 %foo.0.5, !dbg !16 40 41; ModuleID = 'pr38762.cpp' 42source_filename = "pr38762.cpp" 43target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" 44target triple = "x86_64-pc-linux-gnu" 45 46; Function Attrs: norecurse nounwind uwtable 47define dso_local i32 @main() local_unnamed_addr #0 !dbg !7 { 48entry: 49 %foo = alloca i32, align 4 50 store volatile i32 0, ptr %foo, align 4 51 %foo.0. = load volatile i32, ptr %foo, align 4 52 %foo.0.5 = load volatile i32, ptr %foo, align 4 53 call void @llvm.dbg.value(metadata i32 %foo.0.5, metadata !15, metadata !DIExpression()), !dbg !25 54 %cmp = icmp sgt i32 %foo.0., 3, !dbg !26 55 br i1 %cmp, label %if.then, label %if.end, !dbg !28 56 57if.then: ; preds = %entry 58 %mul = shl nsw i32 %foo.0.5, 1, !dbg !29 59 call void @llvm.dbg.value(metadata i32 %mul, metadata !15, metadata !DIExpression()), !dbg !25 60 %add = or i32 %mul, 1, !dbg !31 61 call void @llvm.dbg.value(metadata i32 %add, metadata !15, metadata !DIExpression()), !dbg !25 62 br label %if.end, !dbg !32 63 64if.end: ; preds = %if.then, %entry 65 %brains.0 = phi i32 [ %add, %if.then ], [ %foo.0.5, %entry ], !dbg !33 66 call void @llvm.dbg.value(metadata i32 %brains.0, metadata !15, metadata !DIExpression()), !dbg !25 67 ret i32 %brains.0, !dbg !35 68} 69 70declare void @llvm.dbg.value(metadata, metadata, metadata) #2 71 72!llvm.dbg.cu = !{!0} 73!llvm.module.flags = !{!3, !4, !5} 74!llvm.ident = !{!6} 75 76!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 8.0.0 (trunk 343753)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None) 77!1 = !DIFile(filename: "pr38762.cpp", directory: ".") 78!2 = !{} 79!3 = !{i32 2, !"Dwarf Version", i32 4} 80!4 = !{i32 2, !"Debug Info Version", i32 3} 81!5 = !{i32 1, !"wchar_size", i32 4} 82!6 = !{!"clang version 8.0.0 (trunk 343753)"} 83!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) 84!8 = !DISubroutineType(types: !9) 85!9 = !{!10} 86!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) 87!11 = !{!15} 88!13 = !DIDerivedType(tag: DW_TAG_volatile_type, baseType: !10) 89!15 = !DILocalVariable(name: "brains", scope: !7, file: !1, line: 4, type: !10) 90!25 = !DILocation(line: 4, scope: !7) 91!26 = !DILocation(line: 6, scope: !27) 92!27 = distinct !DILexicalBlock(scope: !7, file: !1, line: 6) 93!28 = !DILocation(line: 6, scope: !7) 94!29 = !DILocation(line: 7, scope: !30) 95!30 = distinct !DILexicalBlock(scope: !27, file: !1, line: 6) 96!31 = !DILocation(line: 8, scope: !30) 97!32 = !DILocation(line: 9, scope: !30) 98!33 = !DILocation(line: 0, scope: !7) 99!34 = !DILocation(line: 12, scope: !7) 100!35 = !DILocation(line: 11, scope: !7) 101