From 1db2fb991e7b32950b4141e85d58d541cdc3dd7c Mon Sep 17 00:00:00 2001 From: Mikael Holmen Date: Wed, 8 Mar 2023 07:34:12 +0100 Subject: [PATCH] Revert "[ADCE] Preserve MemorySSA if only debug instructions are removed" This reverts commit db7d8678bcdc440ffd0529f0d970cf10cbcbe984. --- llvm/lib/Transforms/Scalar/ADCE.cpp | 15 +---- .../preserve-memoryssa-if-only-remove-debug.ll | 70 ---------------------- 2 files changed, 1 insertion(+), 84 deletions(-) delete mode 100644 llvm/test/Transforms/ADCE/preserve-memoryssa-if-only-remove-debug.ll diff --git a/llvm/lib/Transforms/Scalar/ADCE.cpp b/llvm/lib/Transforms/Scalar/ADCE.cpp index ec07c53..d03a503 100644 --- a/llvm/lib/Transforms/Scalar/ADCE.cpp +++ b/llvm/lib/Transforms/Scalar/ADCE.cpp @@ -26,7 +26,6 @@ #include "llvm/Analysis/DomTreeUpdater.h" #include "llvm/Analysis/GlobalsModRef.h" #include "llvm/Analysis/IteratedDominanceFrontier.h" -#include "llvm/Analysis/MemorySSA.h" #include "llvm/Analysis/PostDominators.h" #include "llvm/IR/BasicBlock.h" #include "llvm/IR/CFG.h" @@ -116,7 +115,6 @@ struct BlockInfoType { struct ADCEChanged { bool ChangedAnything = false; - bool ChangedNonDebugInstr = false; bool ChangedControlFlow = false; }; @@ -562,8 +560,6 @@ ADCEChanged AggressiveDeadCodeElimination::removeDeadInstructions() { continue; // Fallthrough and drop the intrinsic. - } else { - Changed.ChangedNonDebugInstr = true; } // Prepare to delete. @@ -717,17 +713,8 @@ PreservedAnalyses ADCEPass::run(Function &F, FunctionAnalysisManager &FAM) { return PreservedAnalyses::all(); PreservedAnalyses PA; - if (!Changed.ChangedControlFlow) { + if (!Changed.ChangedControlFlow) PA.preserveSet(); - if (!Changed.ChangedNonDebugInstr) { - // Only removing debug instructions does not affect MemorySSA. - // - // Therefore we preserve MemorySSA when only removing debug instructions - // since otherwise later passes may behave differently which then makes - // the presence of debug info affect code generation. - PA.preserve(); - } - } PA.preserve(); PA.preserve(); diff --git a/llvm/test/Transforms/ADCE/preserve-memoryssa-if-only-remove-debug.ll b/llvm/test/Transforms/ADCE/preserve-memoryssa-if-only-remove-debug.ll deleted file mode 100644 index 339bc75..0000000 --- a/llvm/test/Transforms/ADCE/preserve-memoryssa-if-only-remove-debug.ll +++ /dev/null @@ -1,70 +0,0 @@ -; RUN: opt -passes='require,adce' -o - -S -debug-pass-manager < %s 2>&1 | FileCheck %s - -; ADCE should remove the dbg.declare in test1, but it should preserve -; MemorySSA since it only removed a debug instruction. - -; Invalidating MemorySSA when only removing debug instructions may lead -; to different code with/without debug info present. -; In -; https://github.com/llvm/llvm-project/issues/58285 -; we saw how ADCE removed a dbg.declare, invalidated all analyses, and later -; DSE behaved in some way. Without the dbg.declare in the input ADCE kept -; analysis info, and DSE behaved differently. - -; CHECK: Running analysis: MemorySSAAnalysis on test1 -; CHECK: Running pass: ADCEPass on test1 (1 instruction) -; CHECK-NOT: Invalidating analysis: MemorySSAAnalysis on test1 - -; In test2 ADCE also removes an instruction, but since we remove a non-debug -; instruction as well we invalidate several analyses, including MemorySSA. - -; CHECK: Running analysis: MemorySSAAnalysis on test2 -; CHECK: Running pass: ADCEPass on test2 (2 instructions) -; CHECK: Invalidating analysis: MemorySSAAnalysis on test2 -; CHECK: Running pass: PrintModulePass - -; CHECK-LABEL: @test1( -; CHECK-NEXT: entry: -; CHECK-NEXT: ret i16 0 - -; CHECK-LABEL: @test2( -; CHECK-NEXT: entry: -; CHECK-NEXT: ret i16 0 - -define i16 @test1() { -entry: - call void @llvm.dbg.declare(metadata ptr undef, metadata !4, metadata !DIExpression()), !dbg !16 - ret i16 0 -} - -define i16 @test2() { -entry: - %dead = add i16 1, 2 - ret i16 0 -} - -; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none) -declare void @llvm.dbg.declare(metadata, metadata, metadata) #0 - -attributes #0 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) } - -!llvm.dbg.cu = !{} -!llvm.module.flags = !{!0, !1, !2, !3} - -!0 = !{i32 7, !"Dwarf Version", i32 4} -!1 = !{i32 2, !"Debug Info Version", i32 3} -!2 = !{i32 1, !"wchar_size", i32 1} -!3 = !{i32 7, !"frame-pointer", i32 2} -!4 = !DILocalVariable(name: "w", scope: !5, file: !6, line: 18, type: !11) -!5 = distinct !DILexicalBlock(scope: !7, file: !6, line: 18, column: 8) -!6 = !DIFile(filename: "foo2.c", directory: "/llvm") -!7 = distinct !DISubprogram(name: "test1", scope: !6, file: !6, line: 14, type: !8, scopeLine: 14, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !10) -!8 = !DISubroutineType(types: !9) -!9 = !{} -!10 = distinct !DICompileUnit(language: DW_LANG_C99, file: !6, producer: "clang version 16.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, globals: !9, splitDebugInlining: false, nameTableKind: None) -!11 = !DIDerivedType(tag: DW_TAG_typedef, name: "uint64_t", file: !12, line: 60, baseType: !13) -!12 = !DIFile(filename: "/include/sys/_stdint.h", directory: "") -!13 = !DIDerivedType(tag: DW_TAG_typedef, name: "__uint64_t", file: !14, line: 108, baseType: !15) -!14 = !DIFile(filename: "/include/machine/_default_types.h", directory: "") -!15 = !DIBasicType(name: "unsigned long long", size: 64, encoding: DW_ATE_unsigned) -!16 = !DILocation(line: 18, column: 8, scope: !5) \ No newline at end of file -- 2.7.4