; Check for setting dbg.value undef which depends on instruction which is going to be dead ; RUN: opt -bdce %s -S | FileCheck %s ; Generated from this ; char a, b; ; void optimize_me_not(); ; int main() { ; char l_177 = 2; ; for (; b <= 0; b++) ; for (; a >= 0; a--) { ; ++l_177; ; optimize_me_not(); ; } ; } @b = common dso_local local_unnamed_addr global i8 0, align 1, !dbg !0 @a = common dso_local local_unnamed_addr global i8 0, align 1, !dbg !6 define dso_local i32 @main() local_unnamed_addr !dbg !13 { entry: ;CHECK: call void @llvm.dbg.value(metadata i8 2 ;CHECK: call void @llvm.dbg.value(metadata i8 2 call void @llvm.dbg.value(metadata i8 2, metadata !17, metadata !DIExpression()), !dbg !18 %.pr = load i8, i8* @b, align 1, !dbg !19 call void @llvm.dbg.value(metadata i8 2, metadata !17, metadata !DIExpression()), !dbg !18 %cmp5 = icmp slt i8 %.pr, 1, !dbg !22 br i1 %cmp5, label %for.cond2thread-pre-split.preheader, label %for.end9, !dbg !23 for.cond2thread-pre-split.preheader: ; preds = %entry br label %for.cond2thread-pre-split, !dbg !23 for.cond2thread-pre-split: ; preds = %for.cond2thread-pre-split.preheader, %for.inc7 ;CHECK: call void @llvm.dbg.value(metadata i8 undef %l_177.06 = phi i8 [ %l_177.1.lcssa, %for.inc7 ], [ 2, %for.cond2thread-pre-split.preheader ] call void @llvm.dbg.value(metadata i8 %l_177.06, metadata !17, metadata !DIExpression()), !dbg !18 ;CHECK: call void @llvm.dbg.value(metadata i8 undef %.pr1 = load i8, i8* @a, align 1, !dbg !24 call void @llvm.dbg.value(metadata i8 %l_177.06, metadata !17, metadata !DIExpression()), !dbg !18 %cmp42 = icmp sgt i8 %.pr1, -1, !dbg !27 br i1 %cmp42, label %for.body6.preheader, label %for.inc7, !dbg !28 for.body6.preheader: ; preds = %for.cond2thread-pre-split br label %for.body6, !dbg !28 for.body6: ; preds = %for.body6.preheader, %for.body6 ;CHECK: call void @llvm.dbg.value(metadata i8 undef ;CHECK: call void @llvm.dbg.value(metadata i8 undef %l_177.13 = phi i8 [ %inc, %for.body6 ], [ %l_177.06, %for.body6.preheader ] call void @llvm.dbg.value(metadata i8 %l_177.13, metadata !17, metadata !DIExpression()), !dbg !18 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 tail call void (...) @optimize_me_not(), !dbg !29 %inc = add i8 %l_177.13, 1, !dbg !31 %0 = load i8, i8* @a, align 1, !dbg !32 %dec = add i8 %0, -1, !dbg !32 store i8 %dec, i8* @a, align 1, !dbg !32 call void @llvm.dbg.value(metadata i8 %inc, metadata !17, metadata !DIExpression()), !dbg !18 %cmp4 = icmp sgt i8 %dec, -1, !dbg !27 br i1 %cmp4, label %for.body6, label %for.inc7.loopexit, !dbg !28, !llvm.loop !33 for.inc7.loopexit: ; preds = %for.body6 %inc.lcssa = phi i8 [ %inc, %for.body6 ], !dbg !31 br label %for.inc7, !dbg !35 for.inc7: ; preds = %for.inc7.loopexit, %for.cond2thread-pre-split ;CHECK: call void @llvm.dbg.value(metadata i8 undef %l_177.1.lcssa = phi i8 [ %l_177.06, %for.cond2thread-pre-split ], [ %inc.lcssa, %for.inc7.loopexit ], !dbg !18 %1 = load i8, i8* @b, align 1, !dbg !35 %inc8 = add i8 %1, 1, !dbg !35 store i8 %inc8, i8* @b, align 1, !dbg !35 call void @llvm.dbg.value(metadata i8 %l_177.1.lcssa, metadata !17, metadata !DIExpression()), !dbg !18 %cmp = icmp slt i8 %inc8, 1, !dbg !22 br i1 %cmp, label %for.cond2thread-pre-split, label %for.end9.loopexit, !dbg !23, !llvm.loop !36 for.end9.loopexit: ; preds = %for.inc7 br label %for.end9, !dbg !38 for.end9: ; preds = %for.end9.loopexit, %entry ret i32 0, !dbg !38 } declare dso_local void @optimize_me_not(...) local_unnamed_addr declare void @llvm.dbg.value(metadata, metadata, metadata) !llvm.dbg.cu = !{!2} !llvm.module.flags = !{!9, !10, !11} !llvm.ident = !{!12} !0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression()) !1 = distinct !DIGlobalVariable(name: "b", scope: !2, file: !3, line: 3, type: !8, isLocal: false, isDefinition: true) !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) !3 = !DIFile(filename: "test", directory: "test") !4 = !{} !5 = !{!6, !0} !6 = !DIGlobalVariableExpression(var: !7, expr: !DIExpression()) !7 = distinct !DIGlobalVariable(name: "a", scope: !2, file: !3, line: 3, type: !8, isLocal: false, isDefinition: true) !8 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char) !9 = !{i32 2, !"Dwarf Version", i32 4} !10 = !{i32 2, !"Debug Info Version", i32 3} !11 = !{i32 1, !"wchar_size", i32 4} !12 = !{!"clang version 10.0.0"} !13 = distinct !DISubprogram(name: "main", scope: !3, file: !3, line: 4, type: !14, scopeLine: 4, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !4) !14 = !DISubroutineType(types: !15) !15 = !{!16} !16 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) !17 = !DILocalVariable(name: "l_177", scope: !13, file: !3, line: 5, type: !8) !18 = !DILocation(line: 0, scope: !13) !19 = !DILocation(line: 6, column: 10, scope: !20) !20 = distinct !DILexicalBlock(scope: !21, file: !3, line: 6, column: 3) !21 = distinct !DILexicalBlock(scope: !13, file: !3, line: 6, column: 3) !22 = !DILocation(line: 6, column: 12, scope: !20) !23 = !DILocation(line: 6, column: 3, scope: !21) !24 = !DILocation(line: 7, column: 12, scope: !25) !25 = distinct !DILexicalBlock(scope: !26, file: !3, line: 7, column: 5) !26 = distinct !DILexicalBlock(scope: !20, file: !3, line: 7, column: 5) !27 = !DILocation(line: 7, column: 14, scope: !25) !28 = !DILocation(line: 7, column: 5, scope: !26) !29 = !DILocation(line: 9, column: 7, scope: !30) !30 = distinct !DILexicalBlock(scope: !25, file: !3, line: 7, column: 25) !31 = !DILocation(line: 8, column: 7, scope: !30) !32 = !DILocation(line: 7, column: 21, scope: !25) !33 = distinct !{!33, !28, !34} !34 = !DILocation(line: 10, column: 5, scope: !26) !35 = !DILocation(line: 6, column: 19, scope: !20) !36 = distinct !{!36, !23, !37} !37 = !DILocation(line: 10, column: 5, scope: !21) !38 = !DILocation(line: 11, column: 1, scope: !13)