Index: lib/Transforms/Utils/SimplifyCFG.cpp =================================================================== --- lib/Transforms/Utils/SimplifyCFG.cpp +++ lib/Transforms/Utils/SimplifyCFG.cpp @@ -1920,6 +1920,8 @@ // - All of their uses are in CondBB. SmallDenseMap SinkCandidateUseCounts; + SmallVector SpeculatedDbgIntrinsics; + unsigned SpeculationCost = 0; Value *SpeculatedStoreValue = nullptr; StoreInst *SpeculatedStore = nullptr; @@ -1928,8 +1930,10 @@ BBI != BBE; ++BBI) { Instruction *I = &*BBI; // Skip debug info. - if (isa(I)) + if (isa(I)) { + SpeculatedDbgIntrinsics.push_back(I); continue; + } // Only speculatively execute a single instruction (not counting the // terminator) for now. @@ -2074,6 +2078,12 @@ PN->setIncomingValue(ThenI, V); } + // Remove speculated dbg intrinsics. + // FIXME: Is it possible to do this in a more elegant way? Moving/merging the + // dbg value for the different flows and inserting it after the select. + for (Instruction *I : SpeculatedDbgIntrinsics) + I->eraseFromParent(); + ++NumSpeculations; return true; } Index: test/Transforms/SimplifyCFG/speculate-dbgvalue.ll =================================================================== --- /dev/null +++ test/Transforms/SimplifyCFG/speculate-dbgvalue.ll @@ -0,0 +1,83 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py +; RUN: opt < %s -S -simplifycfg | FileCheck %s + +; This test case was generated from speculate-dbgvalue.c: +; +; int test1(int getdirt, int dirt) { +; int result = 100; +; if (getdirt != 0) +; result = dirt; +; return result; +; } +; +; using +; clang speculate-dbgvalue.c -S -emit-llvm -g -O3 -mllvm -disable-llvm-optzns -o - | opt -mem2reg -S + + +; Function Attrs: nounwind uwtable +define i32 @test1(i32 %getdirt, i32 %dirt) #0 !dbg !7 { +; CHECK-LABEL: @test1( +; CHECK-NEXT: entry: +; CHECK-NEXT: call void @llvm.dbg.value(metadata i32 [[GETDIRT:%.*]], metadata !12, metadata !DIExpression()), !dbg !15 +; CHECK-NEXT: call void @llvm.dbg.value(metadata i32 [[DIRT:%.*]], metadata !13, metadata !DIExpression()), !dbg !16 +; CHECK-NEXT: call void @llvm.dbg.value(metadata i32 100, metadata !14, metadata !DIExpression()), !dbg !17 +; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[GETDIRT]], 0, !dbg !18 +; *** We used to get an incorrect "call void @llvm.dbg.value(metadata i32 [[DIRT]], metadata !14, metadata !DIExpression()), !dbg !17" here, before the select. *** +; CHECK-NOT: call void @llvm.dbg.value(metadata i32 [[DIRT]], metadata !14 +; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[CMP]], i32 [[DIRT]], i32 100, !dbg !20 +; CHECK-NEXT: call void @llvm.dbg.value(metadata i32 [[RESULT]], metadata !14, metadata !DIExpression()), !dbg !17 +; CHECK-NEXT: ret i32 [[RESULT]], !dbg !21 +; CHECK: !12 = !DILocalVariable(name: "getdirt" +; CHECK: !13 = !DILocalVariable(name: "dirt" +; CHECK: !14 = !DILocalVariable(name: "result" +; +entry: + call void @llvm.dbg.value(metadata i32 %getdirt, metadata !12, metadata !DIExpression()), !dbg !15 + call void @llvm.dbg.value(metadata i32 %dirt, metadata !13, metadata !DIExpression()), !dbg !16 + call void @llvm.dbg.value(metadata i32 100, metadata !14, metadata !DIExpression()), !dbg !17 + %cmp = icmp ne i32 %getdirt, 0, !dbg !18 + br i1 %cmp, label %if.then, label %if.end, !dbg !20 + +if.then: ; preds = %entry + call void @llvm.dbg.value(metadata i32 %dirt, metadata !14, metadata !DIExpression()), !dbg !17 + br label %if.end, !dbg !21 + +if.end: ; preds = %if.then, %entry + %result.0 = phi i32 [ %dirt, %if.then ], [ 100, %entry ] + call void @llvm.dbg.value(metadata i32 %result.0, metadata !14, metadata !DIExpression()), !dbg !17 + ret i32 %result.0, !dbg !22 +} + +; Function Attrs: nounwind readnone speculatable +declare void @llvm.dbg.value(metadata, metadata, metadata) #1 + +attributes #0 = { nounwind uwtable } +attributes #1 = { nounwind readnone speculatable } + +!llvm.dbg.cu = !{!0} +!llvm.module.flags = !{!3, !4, !5} +!llvm.ident = !{!6} + +!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 6.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2) +!1 = !DIFile(filename: "speculate-dbgvalue.c", directory: "/foo") +!2 = !{} +!3 = !{i32 2, !"Dwarf Version", i32 4} +!4 = !{i32 2, !"Debug Info Version", i32 3} +!5 = !{i32 1, !"wchar_size", i32 4} +!6 = !{!"clang version 6.0.0"} +!7 = distinct !DISubprogram(name: "test1", scope: !1, file: !1, line: 1, type: !8, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !11) +!8 = !DISubroutineType(types: !9) +!9 = !{!10, !10, !10} +!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!11 = !{!12, !13, !14} +!12 = !DILocalVariable(name: "getdirt", arg: 1, scope: !7, file: !1, line: 1, type: !10) +!13 = !DILocalVariable(name: "dirt", arg: 2, scope: !7, file: !1, line: 1, type: !10) +!14 = !DILocalVariable(name: "result", scope: !7, file: !1, line: 2, type: !10) +!15 = !DILocation(line: 1, column: 15, scope: !7) +!16 = !DILocation(line: 1, column: 28, scope: !7) +!17 = !DILocation(line: 2, column: 7, scope: !7) +!18 = !DILocation(line: 3, column: 15, scope: !19) +!19 = distinct !DILexicalBlock(scope: !7, file: !1, line: 3, column: 7) +!20 = !DILocation(line: 3, column: 7, scope: !7) +!21 = !DILocation(line: 4, column: 5, scope: !19) +!22 = !DILocation(line: 5, column: 3, scope: !7)