From 083e9d71ec9c91568fceaf4f7a29cebca7750f8c Mon Sep 17 00:00:00 2001 From: Apochens Date: Thu, 17 Jul 2025 13:09:11 +0000 Subject: [PATCH 1/2] fix 147634 --- llvm/lib/Transforms/Scalar/NewGVN.cpp | 1 + .../NewGVN/salvage-trivially-dead-inst.ll | 58 +++++++++++++++++++ 2 files changed, 59 insertions(+) create mode 100644 llvm/test/Transforms/NewGVN/salvage-trivially-dead-inst.ll 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..1845cf6f0852c --- /dev/null +++ b/llvm/test/Transforms/NewGVN/salvage-trivially-dead-inst.ll @@ -0,0 +1,58 @@ +; 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: 3 + +define void @test13() !dbg !5 { +bb: + br label %bb1 + +bb1: + %tmp = load i8, ptr null, align 1 + %tmp2 = icmp eq i8 %tmp, 8, !dbg !26 + #dbg_value(i1 %tmp2, !11, !DIExpression(), !26) + br label %bb3 + +bb3: + %tmp4 = phi ptr [ null, %bb1 ], [ %tmp6, %bb3 ] + %tmp5 = phi i32 [ undef, %bb1 ], [ %tmp9, %bb3 ] + %tmp6 = getelementptr i8, ptr %tmp4, i64 1 + %tmp7 = load i8, ptr %tmp4, align 1 + %tmp8 = sext i8 %tmp7 to i32 + %tmp9 = mul i32 %tmp5, %tmp8 + %tmp10 = load i8, ptr %tmp6, align 1 + %tmp11 = icmp eq i8 %tmp10, 0 + br i1 %tmp11, label %bb12, label %bb3 + +bb12: + %tmp13 = phi i32 [ %tmp9, %bb3 ] + %tmp14 = icmp eq i32 %tmp13, 0 + br i1 %tmp14, label %bb1, label %bb15 + +bb15: + call void (...) @bar() + br label %bb1 +} + +declare void @bar(...) + +!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 18} +!3 = !{i32 12} +!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: 3, type: !10) +!26 = !DILocation(line: 3, column: 1, scope: !5) \ No newline at end of file From 680cafdfac9160c4bad941a8e43a76c608a8936c Mon Sep 17 00:00:00 2001 From: Apochens Date: Thu, 17 Jul 2025 14:02:16 +0000 Subject: [PATCH 2/2] refine the regression test --- .../NewGVN/salvage-trivially-dead-inst.ll | 43 ++++--------------- 1 file changed, 9 insertions(+), 34 deletions(-) diff --git a/llvm/test/Transforms/NewGVN/salvage-trivially-dead-inst.ll b/llvm/test/Transforms/NewGVN/salvage-trivially-dead-inst.ll index 1845cf6f0852c..cc695417bc4e6 100644 --- a/llvm/test/Transforms/NewGVN/salvage-trivially-dead-inst.ll +++ b/llvm/test/Transforms/NewGVN/salvage-trivially-dead-inst.ll @@ -5,54 +5,29 @@ ; 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: 3 +; CHECK: [[META26]] = !DILocation(line: 2 define void @test13() !dbg !5 { -bb: - br label %bb1 - -bb1: +entry: %tmp = load i8, ptr null, align 1 - %tmp2 = icmp eq i8 %tmp, 8, !dbg !26 - #dbg_value(i1 %tmp2, !11, !DIExpression(), !26) - br label %bb3 - -bb3: - %tmp4 = phi ptr [ null, %bb1 ], [ %tmp6, %bb3 ] - %tmp5 = phi i32 [ undef, %bb1 ], [ %tmp9, %bb3 ] - %tmp6 = getelementptr i8, ptr %tmp4, i64 1 - %tmp7 = load i8, ptr %tmp4, align 1 - %tmp8 = sext i8 %tmp7 to i32 - %tmp9 = mul i32 %tmp5, %tmp8 - %tmp10 = load i8, ptr %tmp6, align 1 - %tmp11 = icmp eq i8 %tmp10, 0 - br i1 %tmp11, label %bb12, label %bb3 - -bb12: - %tmp13 = phi i32 [ %tmp9, %bb3 ] - %tmp14 = icmp eq i32 %tmp13, 0 - br i1 %tmp14, label %bb1, label %bb15 - -bb15: - call void (...) @bar() - br label %bb1 + %tmp2 = icmp eq i8 %tmp, 8, !dbg !13 + #dbg_value(i1 %tmp2, !11, !DIExpression(), !13) + ret void } -declare void @bar(...) - !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 18} -!3 = !{i32 12} +!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: 3, type: !10) -!26 = !DILocation(line: 3, column: 1, scope: !5) \ No newline at end of file +!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