From: Davide Italiano Date: Mon, 4 Mar 2019 04:38:58 +0000 (+0000) Subject: [InstCombine] Mark debug values as unavailable after DCE. X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=5e23016546fe3b793c1882f9ce08a1ec247380a0;p=llvm [InstCombine] Mark debug values as unavailable after DCE. Fixes PR40838. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@355301 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp index 723bb4c0d68..d5cc7c5bf7e 100644 --- a/lib/Transforms/InstCombine/InstructionCombining.cpp +++ b/lib/Transforms/InstCombine/InstructionCombining.cpp @@ -3323,7 +3323,8 @@ static bool AddReachableCodeToWorklist(BasicBlock *BB, const DataLayout &DL, if (isInstructionTriviallyDead(Inst, TLI)) { ++NumDeadInst; LLVM_DEBUG(dbgs() << "IC: DCE: " << *Inst << '\n'); - salvageDebugInfo(*Inst); + if (!salvageDebugInfo(*Inst)) + replaceDbgUsesWithUndef(Inst); Inst->eraseFromParent(); MadeIRChange = true; continue; diff --git a/test/Transforms/InstCombine/unavailable-debug.ll b/test/Transforms/InstCombine/unavailable-debug.ll new file mode 100644 index 00000000000..703c1c2898f --- /dev/null +++ b/test/Transforms/InstCombine/unavailable-debug.ll @@ -0,0 +1,81 @@ +; RUN: opt < %s -instcombine -S | FileCheck %s + +; Make sure to update the debug value after dead code elimination. +; CHECK: %call = call signext i8 @b(i32 6), !dbg !39 +; CHECK-NEXT: call void @llvm.dbg.value(metadata i32 undef, metadata !30, metadata !DIExpression()), !dbg !38 + +@e = common local_unnamed_addr global i8 0, align 1, !dbg !0 +@c = common local_unnamed_addr global i32 0, align 4, !dbg !6 +@d = common local_unnamed_addr global i32 0, align 4, !dbg !10 + +define signext i8 @b(i32 %f) local_unnamed_addr #0 !dbg !18 { +entry: + call void @llvm.dbg.value(metadata i32 %f, metadata !22, metadata !DIExpression()), !dbg !23 + %conv = trunc i32 %f to i8, !dbg !24 + ret i8 %conv, !dbg !25 +} + +define i32 @main() local_unnamed_addr #0 !dbg !26 { +entry: + %0 = load i8, i8* @e, align 1, !dbg !31, !tbaa !32 + %conv = sext i8 %0 to i32, !dbg !31 + store i32 %conv, i32* @c, align 4, !dbg !35, !tbaa !36 + call void @llvm.dbg.value(metadata i32 -1372423381, metadata !30, metadata !DIExpression()), !dbg !38 + %call = call signext i8 @b(i32 6), !dbg !39 + %conv1 = sext i8 %call to i32, !dbg !39 + call void @llvm.dbg.value(metadata i32 %conv1, metadata !30, metadata !DIExpression()), !dbg !38 + %1 = load i32, i32* @d, align 4, !dbg !40, !tbaa !36 + %call2 = call i32 (...) @optimize_me_not(), !dbg !41 + ret i32 0, !dbg !42 +} + +declare i32 @optimize_me_not(...) local_unnamed_addr #1 +declare void @llvm.dbg.value(metadata, metadata, metadata) #2 + +!llvm.dbg.cu = !{!2} +!llvm.module.flags = !{!13, !14, !15, !16} +!llvm.ident = !{!17} + +!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression()) +!1 = distinct !DIGlobalVariable(name: "e", scope: !2, file: !3, line: 3, type: !12, isLocal: false, isDefinition: true) +!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 9.0.0 (https://github.com/llvm/llvm-project b306ef12f046353ea5bda4b3b77759e57909a0db)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, nameTableKind: GNU) +!3 = !DIFile(filename: "a.c", directory: "/Users/davide/llvm/build/bin") +!4 = !{} +!5 = !{!6, !10, !0} +!6 = !DIGlobalVariableExpression(var: !7, expr: !DIExpression()) +!7 = distinct !DIGlobalVariable(name: "c", scope: !2, file: !3, line: 2, type: !8, isLocal: false, isDefinition: true) +!8 = !DIDerivedType(tag: DW_TAG_typedef, name: "a", file: !3, line: 1, baseType: !9) +!9 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!10 = !DIGlobalVariableExpression(var: !11, expr: !DIExpression()) +!11 = distinct !DIGlobalVariable(name: "d", scope: !2, file: !3, line: 2, type: !8, isLocal: false, isDefinition: true) +!12 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char) +!13 = !{i32 2, !"Dwarf Version", i32 4} +!14 = !{i32 2, !"Debug Info Version", i32 3} +!15 = !{i32 1, !"wchar_size", i32 4} +!16 = !{i32 7, !"PIC Level", i32 2} +!17 = !{!"clang version 9.0.0 (https://github.com/llvm/llvm-project b306ef12f046353ea5bda4b3b77759e57909a0db)"} +!18 = distinct !DISubprogram(name: "b", scope: !3, file: !3, line: 4, type: !19, scopeLine: 4, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !21) +!19 = !DISubroutineType(types: !20) +!20 = !{!12, !9} +!21 = !{!22} +!22 = !DILocalVariable(name: "f", arg: 1, scope: !18, file: !3, line: 4, type: !9) +!23 = !DILocation(line: 4, column: 9, scope: !18) +!24 = !DILocation(line: 4, column: 21, scope: !18) +!25 = !DILocation(line: 4, column: 14, scope: !18) +!26 = distinct !DISubprogram(name: "main", scope: !3, file: !3, line: 5, type: !27, scopeLine: 5, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !29) +!27 = !DISubroutineType(types: !28) +!28 = !{!9} +!29 = !{!30} +!30 = !DILocalVariable(name: "l_1499", scope: !26, file: !3, line: 7, type: !8) +!31 = !DILocation(line: 6, column: 7, scope: !26) +!32 = !{!33, !33, i64 0} +!33 = !{!"omnipotent char", !34, i64 0} +!34 = !{!"Simple C/C++ TBAA"} +!35 = !DILocation(line: 6, column: 5, scope: !26) +!36 = !{!37, !37, i64 0} +!37 = !{!"int", !33, i64 0} +!38 = !DILocation(line: 7, column: 5, scope: !26) +!39 = !DILocation(line: 8, column: 12, scope: !26) +!40 = !DILocation(line: 9, column: 11, scope: !26) +!41 = !DILocation(line: 10, column: 3, scope: !26) +!42 = !DILocation(line: 11, column: 1, scope: !26)