101 lines · plain
1; RUN: opt < %s -S -passes=simplifycfg | FileCheck %s2 3; Note: This patch is a complement to pr38763.4;5; When SimplifyCFG changes the PHI node into a select instruction, the debug6; information becomes ambiguous. It causes the debugger to display unreached7; lines and invalid variable values.8;9; When in the debugger, on the line "if (read1 > 3)", and we step from the10; 'if' condition, onto the addition, then back to the 'if' again, which is11; 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=1015 16; // pr38762.cpp17; 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, to31; the debug locations from the insertion point in the dominant block.32 33; CHECK-LABEL: entry34; CHECK: %cmp = icmp sgt i32 %foo.0., 3, !dbg !1435; CHECK: %mul = shl nsw i32 %foo.0.5, 1, !dbg !1636; CHECK-NOT: call void @llvm.dbg.value(metadata i32 %mul, metadata !15, metadata !DIExpression()), !dbg !2537; CHECK: %add = or i32 %mul, 1, !dbg !1638; CHECK-NOT: call void @llvm.dbg.value(metadata i32 %add, metadata !15, metadata !DIExpression()), !dbg !2539; CHECK: %brains.0 = select i1 %cmp, i32 %add, i32 %foo.0.5, !dbg !1640 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 uwtable47define dso_local i32 @main() local_unnamed_addr #0 !dbg !7 {48entry:49 %foo = alloca i32, align 450 store volatile i32 0, ptr %foo, align 451 %foo.0. = load volatile i32, ptr %foo, align 452 %foo.0.5 = load volatile i32, ptr %foo, align 453 call void @llvm.dbg.value(metadata i32 %foo.0.5, metadata !15, metadata !DIExpression()), !dbg !2554 %cmp = icmp sgt i32 %foo.0., 3, !dbg !2655 br i1 %cmp, label %if.then, label %if.end, !dbg !2856 57if.then: ; preds = %entry58 %mul = shl nsw i32 %foo.0.5, 1, !dbg !2959 call void @llvm.dbg.value(metadata i32 %mul, metadata !15, metadata !DIExpression()), !dbg !2560 %add = or i32 %mul, 1, !dbg !3161 call void @llvm.dbg.value(metadata i32 %add, metadata !15, metadata !DIExpression()), !dbg !2562 br label %if.end, !dbg !3263 64if.end: ; preds = %if.then, %entry65 %brains.0 = phi i32 [ %add, %if.then ], [ %foo.0.5, %entry ], !dbg !3366 call void @llvm.dbg.value(metadata i32 %brains.0, metadata !15, metadata !DIExpression()), !dbg !2567 ret i32 %brains.0, !dbg !3568}69 70declare void @llvm.dbg.value(metadata, metadata, metadata) #271 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