1; Check for setting dbg.value undef which depends on instruction which is going to be dead 2; RUN: opt -bdce %s -S | FileCheck %s 3 4; Generated from this 5; char a, b; 6; void optimize_me_not(); 7; int main() { 8; char l_177 = 2; 9; for (; b <= 0; b++) 10; for (; a >= 0; a--) { 11; ++l_177; 12; optimize_me_not(); 13; } 14; } 15 16@b = common dso_local local_unnamed_addr global i8 0, align 1, !dbg !0 17@a = common dso_local local_unnamed_addr global i8 0, align 1, !dbg !6 18 19define dso_local i32 @main() local_unnamed_addr !dbg !13 { 20entry: 21;CHECK: call void @llvm.dbg.value(metadata i8 2 22;CHECK: call void @llvm.dbg.value(metadata i8 2 23 call void @llvm.dbg.value(metadata i8 2, metadata !17, metadata !DIExpression()), !dbg !18 24 %.pr = load i8, i8* @b, align 1, !dbg !19 25 call void @llvm.dbg.value(metadata i8 2, metadata !17, metadata !DIExpression()), !dbg !18 26 %cmp5 = icmp slt i8 %.pr, 1, !dbg !22 27 br i1 %cmp5, label %for.cond2thread-pre-split.preheader, label %for.end9, !dbg !23 28 29for.cond2thread-pre-split.preheader: ; preds = %entry 30 br label %for.cond2thread-pre-split, !dbg !23 31for.cond2thread-pre-split: ; preds = %for.cond2thread-pre-split.preheader, %for.inc7 32;CHECK: call void @llvm.dbg.value(metadata i8 undef 33 %l_177.06 = phi i8 [ %l_177.1.lcssa, %for.inc7 ], [ 2, %for.cond2thread-pre-split.preheader ] 34 call void @llvm.dbg.value(metadata i8 %l_177.06, metadata !17, metadata !DIExpression()), !dbg !18 35;CHECK: call void @llvm.dbg.value(metadata i8 undef 36 %.pr1 = load i8, i8* @a, align 1, !dbg !24 37 call void @llvm.dbg.value(metadata i8 %l_177.06, metadata !17, metadata !DIExpression()), !dbg !18 38 %cmp42 = icmp sgt i8 %.pr1, -1, !dbg !27 39 br i1 %cmp42, label %for.body6.preheader, label %for.inc7, !dbg !28 40 41for.body6.preheader: ; preds = %for.cond2thread-pre-split 42 br label %for.body6, !dbg !28 43 44for.body6: ; preds = %for.body6.preheader, %for.body6 45;CHECK: call void @llvm.dbg.value(metadata i8 undef 46;CHECK: call void @llvm.dbg.value(metadata i8 undef 47 %l_177.13 = phi i8 [ %inc, %for.body6 ], [ %l_177.06, %for.body6.preheader ] 48 call void @llvm.dbg.value(metadata i8 %l_177.13, metadata !17, metadata !DIExpression()), !dbg !18 49 call void @llvm.dbg.value(metadata i8 %l_177.13, metadata !17, metadata !DIExpression(DW_OP_plus_uconst, 1, DW_OP_stack_value)), !dbg !18 50 tail call void (...) @optimize_me_not(), !dbg !29 51 %inc = add i8 %l_177.13, 1, !dbg !31 52 %0 = load i8, i8* @a, align 1, !dbg !32 53 %dec = add i8 %0, -1, !dbg !32 54 store i8 %dec, i8* @a, align 1, !dbg !32 55 call void @llvm.dbg.value(metadata i8 %inc, metadata !17, metadata !DIExpression()), !dbg !18 56 %cmp4 = icmp sgt i8 %dec, -1, !dbg !27 57 br i1 %cmp4, label %for.body6, label %for.inc7.loopexit, !dbg !28, !llvm.loop !33 58 59for.inc7.loopexit: ; preds = %for.body6 60 %inc.lcssa = phi i8 [ %inc, %for.body6 ], !dbg !31 61 br label %for.inc7, !dbg !35 62 63for.inc7: ; preds = %for.inc7.loopexit, %for.cond2thread-pre-split 64;CHECK: call void @llvm.dbg.value(metadata i8 undef 65 %l_177.1.lcssa = phi i8 [ %l_177.06, %for.cond2thread-pre-split ], [ %inc.lcssa, %for.inc7.loopexit ], !dbg !18 66 %1 = load i8, i8* @b, align 1, !dbg !35 67 %inc8 = add i8 %1, 1, !dbg !35 68 store i8 %inc8, i8* @b, align 1, !dbg !35 69 call void @llvm.dbg.value(metadata i8 %l_177.1.lcssa, metadata !17, metadata !DIExpression()), !dbg !18 70 %cmp = icmp slt i8 %inc8, 1, !dbg !22 71 br i1 %cmp, label %for.cond2thread-pre-split, label %for.end9.loopexit, !dbg !23, !llvm.loop !36 72 73for.end9.loopexit: ; preds = %for.inc7 74 br label %for.end9, !dbg !38 75 76for.end9: ; preds = %for.end9.loopexit, %entry 77 ret i32 0, !dbg !38 78} 79 80declare dso_local void @optimize_me_not(...) local_unnamed_addr 81 82declare void @llvm.dbg.value(metadata, metadata, metadata) 83 84!llvm.dbg.cu = !{!2} 85!llvm.module.flags = !{!9, !10, !11} 86!llvm.ident = !{!12} 87 88!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression()) 89!1 = distinct !DIGlobalVariable(name: "b", scope: !2, file: !3, line: 3, type: !8, isLocal: false, isDefinition: true) 90!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 10.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, nameTableKind: None) 91!3 = !DIFile(filename: "test", directory: "test") 92!4 = !{} 93!5 = !{!6, !0} 94!6 = !DIGlobalVariableExpression(var: !7, expr: !DIExpression()) 95!7 = distinct !DIGlobalVariable(name: "a", scope: !2, file: !3, line: 3, type: !8, isLocal: false, isDefinition: true) 96!8 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char) 97!9 = !{i32 2, !"Dwarf Version", i32 4} 98!10 = !{i32 2, !"Debug Info Version", i32 3} 99!11 = !{i32 1, !"wchar_size", i32 4} 100!12 = !{!"clang version 10.0.0"} 101!13 = distinct !DISubprogram(name: "main", scope: !3, file: !3, line: 4, type: !14, scopeLine: 4, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !4) 102!14 = !DISubroutineType(types: !15) 103!15 = !{!16} 104!16 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) 105!17 = !DILocalVariable(name: "l_177", scope: !13, file: !3, line: 5, type: !8) 106!18 = !DILocation(line: 0, scope: !13) 107!19 = !DILocation(line: 6, column: 10, scope: !20) 108!20 = distinct !DILexicalBlock(scope: !21, file: !3, line: 6, column: 3) 109!21 = distinct !DILexicalBlock(scope: !13, file: !3, line: 6, column: 3) 110!22 = !DILocation(line: 6, column: 12, scope: !20) 111!23 = !DILocation(line: 6, column: 3, scope: !21) 112!24 = !DILocation(line: 7, column: 12, scope: !25) 113!25 = distinct !DILexicalBlock(scope: !26, file: !3, line: 7, column: 5) 114!26 = distinct !DILexicalBlock(scope: !20, file: !3, line: 7, column: 5) 115!27 = !DILocation(line: 7, column: 14, scope: !25) 116!28 = !DILocation(line: 7, column: 5, scope: !26) 117!29 = !DILocation(line: 9, column: 7, scope: !30) 118!30 = distinct !DILexicalBlock(scope: !25, file: !3, line: 7, column: 25) 119!31 = !DILocation(line: 8, column: 7, scope: !30) 120!32 = !DILocation(line: 7, column: 21, scope: !25) 121!33 = distinct !{!33, !28, !34} 122!34 = !DILocation(line: 10, column: 5, scope: !26) 123!35 = !DILocation(line: 6, column: 19, scope: !20) 124!36 = distinct !{!36, !23, !37} 125!37 = !DILocation(line: 10, column: 5, scope: !21) 126!38 = !DILocation(line: 11, column: 1, scope: !13) 127