diff --git a/llvm/lib/Transforms/Scalar/NewGVN.cpp b/llvm/lib/Transforms/Scalar/NewGVN.cpp index 7eeaaa0d99602..17c4fd9c2aae9 100644 --- a/llvm/lib/Transforms/Scalar/NewGVN.cpp +++ b/llvm/lib/Transforms/Scalar/NewGVN.cpp @@ -3044,6 +3044,7 @@ std::pair NewGVN::assignDFSNumbers(BasicBlock *B, if (isInstructionTriviallyDead(&I, TLI)) { InstrDFS[&I] = 0; LLVM_DEBUG(dbgs() << "Skipping trivially dead instruction " << I << "\n"); + salvageDebugInfo(I); markInstructionForDeletion(&I); continue; } diff --git a/llvm/test/Transforms/NewGVN/salvage-trivially-dead-inst.ll b/llvm/test/Transforms/NewGVN/salvage-trivially-dead-inst.ll new file mode 100644 index 0000000000000..cc695417bc4e6 --- /dev/null +++ b/llvm/test/Transforms/NewGVN/salvage-trivially-dead-inst.ll @@ -0,0 +1,33 @@ +; RUN: opt -passes=newgvn -S %s | FileCheck %s + +; Check that assignDFSNumbers() in NewGVN salvages the debug values of the +; trivially dead instructions that are marked for deletion. + +; CHECK: #dbg_value(i8 %tmp, [[META11:![0-9]+]], !DIExpression(DW_OP_constu, 8, DW_OP_eq, DW_OP_stack_value), [[META26:![0-9]+]]) +; CHECK: [[META11]] = !DILocalVariable(name: "2" +; CHECK: [[META26]] = !DILocation(line: 2 + +define void @test13() !dbg !5 { +entry: + %tmp = load i8, ptr null, align 1 + %tmp2 = icmp eq i8 %tmp, 8, !dbg !13 + #dbg_value(i1 %tmp2, !11, !DIExpression(), !13) + ret void +} + +!llvm.dbg.cu = !{!0} +!llvm.debugify = !{!2, !3} +!llvm.module.flags = !{!4} + +!0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug) +!1 = !DIFile(filename: "/app/example.ll", directory: "/") +!2 = !{i32 3} +!3 = !{i32 2} +!4 = !{i32 2, !"Debug Info Version", i32 3} +!5 = distinct !DISubprogram(name: "test13", linkageName: "test13", scope: null, file: !1, line: 1, type: !6, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !8) +!6 = !DISubroutineType(types: !7) +!7 = !{} +!8 = !{!11} +!10 = !DIBasicType(name: "ty8", size: 8, encoding: DW_ATE_unsigned) +!11 = !DILocalVariable(name: "2", scope: !5, file: !1, line: 2, type: !10) +!13 = !DILocation(line: 2, column: 1, scope: !5) \ No newline at end of file