Index: llvm/lib/Transforms/Utils/LoopUtils.cpp =================================================================== --- llvm/lib/Transforms/Utils/LoopUtils.cpp +++ llvm/lib/Transforms/Utils/LoopUtils.cpp @@ -26,9 +26,11 @@ #include "llvm/Analysis/ScalarEvolutionExpressions.h" #include "llvm/Analysis/TargetTransformInfo.h" #include "llvm/Analysis/ValueTracking.h" +#include "llvm/IR/DIBuilder.h" #include "llvm/IR/DomTreeUpdater.h" #include "llvm/IR/Dominators.h" #include "llvm/IR/Instructions.h" +#include "llvm/IR/IntrinsicInst.h" #include "llvm/IR/Module.h" #include "llvm/IR/PatternMatch.h" #include "llvm/IR/ValueHandle.h" @@ -336,6 +338,8 @@ DTU.deleteEdge(Preheader, L->getHeader()); } + llvm::SmallVector DeadDebugInst; + // Given LCSSA form is satisfied, we should not have users of instructions // within the dead loop outside of the loop. However, LCSSA doesn't take // unreachable uses into account. We handle them here. @@ -360,8 +364,18 @@ "Unexpected user in reachable block"); U.set(Undef); } + if (auto *DVI = dyn_cast(&I)) + DeadDebugInst.push_back(DVI); } + // After the loop has been deleted all the values defined and modified + // inside the loop are going to be unavailable. + DIBuilder DIB(*ExitBlock->getModule()); + for (auto *DVI : DeadDebugInst) + DIB.insertDbgValueIntrinsic( + UndefValue::get(DVI->getType()), DVI->getVariable(), + DVI->getExpression(), DVI->getDebugLoc(), ExitBlock->getFirstNonPHI()); + // Remove the block from the reference counting scheme, so that we can // delete it freely later. for (auto *Block : L->blocks()) Index: llvm/test/Transforms/LoopDeletion/diundef.ll =================================================================== --- /dev/null +++ llvm/test/Transforms/LoopDeletion/diundef.ll @@ -0,0 +1,83 @@ +; RUN: opt %s -loop-deletion -S | FileCheck %s + +target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-apple-macosx10.14.0" + +@a = common local_unnamed_addr global i32 0, align 4, !dbg !0 + +define i32 @b() local_unnamed_addr #0 !dbg !12 { +entry: + call void @llvm.dbg.value(metadata i32 0, metadata !16, metadata !DIExpression()), !dbg !17 + br label %for.cond, !dbg !18 + +for.cond: ; preds = %for.cond, %entry + %i.0 = phi i32 [ 0, %entry ], [ %inc, %for.cond ], !dbg !20 + call void @llvm.dbg.value(metadata i32 %i.0, metadata !16, metadata !DIExpression()), !dbg !17 + %inc = add nuw nsw i32 %i.0, 1, !dbg !21 + call void @llvm.dbg.value(metadata i32 %inc, metadata !16, metadata !DIExpression()), !dbg !17 + %exitcond = icmp ne i32 %inc, 3, !dbg !23 + br i1 %exitcond, label %for.cond, label %for.end, !dbg !24, !llvm.loop !25 + +; CHECK: call void @llvm.dbg.value(metadata void undef, metadata !16, metadata !DIExpression()), !dbg !17 +for.end: ; preds = %for.cond + %call = tail call i32 (...) @patatino() #3, !dbg !27 + %0 = load i32, i32* @a, align 4, !dbg !28, !tbaa !29 + ret i32 %0, !dbg !33 +} + +declare i32 @patatino(...) local_unnamed_addr #1 + +define i32 @main() local_unnamed_addr #0 !dbg !34 { +entry: + %call = call i32 @b(), !dbg !35 + ret i32 0, !dbg !36 +} + +declare void @llvm.dbg.value(metadata, metadata, metadata) #2 + +attributes #0 = { nounwind ssp uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="penryn" "target-features"="+cx16,+fxsr,+mmx,+sahf,+sse,+sse2,+sse3,+sse4.1,+ssse3,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" } +attributes #1 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="penryn" "target-features"="+cx16,+fxsr,+mmx,+sahf,+sse,+sse2,+sse3,+sse4.1,+ssse3,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" } +attributes #2 = { nounwind readnone speculatable } +attributes #3 = { nounwind } + +!llvm.dbg.cu = !{!2} +!llvm.module.flags = !{!7, !8, !9, !10} +!llvm.ident = !{!11} + +!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression()) +!1 = distinct !DIGlobalVariable(name: "a", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true) +!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 8.0.0 ", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, nameTableKind: GNU) +!3 = !DIFile(filename: "a.c", directory: "/Users/davide/work/llvm-project-20170507/build-debug/bin") +!4 = !{} +!5 = !{!0} +!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!7 = !{i32 2, !"Dwarf Version", i32 4} +!8 = !{i32 2, !"Debug Info Version", i32 3} +!9 = !{i32 1, !"wchar_size", i32 4} +!10 = !{i32 7, !"PIC Level", i32 2} +!11 = !{!"clang version 8.0.0 "} +!12 = distinct !DISubprogram(name: "b", scope: !3, file: !3, line: 2, type: !13, scopeLine: 2, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !15) +!13 = !DISubroutineType(types: !14) +!14 = !{!6} +!15 = !{!16} +!16 = !DILocalVariable(name: "i", scope: !12, file: !3, line: 3, type: !6) +!17 = !DILocation(line: 3, column: 7, scope: !12) +!18 = !DILocation(line: 4, column: 8, scope: !19) +!19 = distinct !DILexicalBlock(scope: !12, file: !3, line: 4, column: 3) +!20 = !DILocation(line: 0, scope: !19) +!21 = !DILocation(line: 4, column: 23, scope: !22) +!22 = distinct !DILexicalBlock(scope: !19, file: !3, line: 4, column: 3) +!23 = !DILocation(line: 4, column: 17, scope: !22) +!24 = !DILocation(line: 4, column: 3, scope: !19) +!25 = distinct !{!25, !24, !26} +!26 = !DILocation(line: 5, column: 5, scope: !19) +!27 = !DILocation(line: 6, column: 3, scope: !12) +!28 = !DILocation(line: 7, column: 10, scope: !12) +!29 = !{!30, !30, i64 0} +!30 = !{!"int", !31, i64 0} +!31 = !{!"omnipotent char", !32, i64 0} +!32 = !{!"Simple C/C++ TBAA"} +!33 = !DILocation(line: 7, column: 3, scope: !12) +!34 = distinct !DISubprogram(name: "main", scope: !3, file: !3, line: 9, type: !13, scopeLine: 9, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !4) +!35 = !DILocation(line: 9, column: 14, scope: !34) +!36 = !DILocation(line: 9, column: 19, scope: !34)