diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp index 7b36907f70114..3d72556b2aed3 100644 --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp @@ -2141,9 +2141,14 @@ bool SimplifyCFGOpt::SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *ThenBB, } // Metadata can be dependent on the condition we are hoisting above. - // Conservatively strip all metadata on the instruction. - for (auto &I : *ThenBB) + // Conservatively strip all metadata on the instruction. Drop the debug loc + // to avoid making it appear as if the condition is a constant, which would + // be misleading while debugging. + for (auto &I : *ThenBB) { + if (!SpeculatedStoreValue || &I != SpeculatedStore) + I.setDebugLoc(DebugLoc()); I.dropUnknownNonDebugMetadata(); + } // Hoist the instructions. BB->getInstList().splice(BI->getIterator(), ThenBB->getInstList(), diff --git a/llvm/test/Transforms/SimplifyCFG/drop-debug-loc-when-speculating.ll b/llvm/test/Transforms/SimplifyCFG/drop-debug-loc-when-speculating.ll new file mode 100644 index 0000000000000..6298b4e5de35c --- /dev/null +++ b/llvm/test/Transforms/SimplifyCFG/drop-debug-loc-when-speculating.ll @@ -0,0 +1,39 @@ +; RUN: opt -S -o - %s -simplifycfg | FileCheck %s + +declare i1 @make_condition() + +; CHECK-LABEL: @test1( +; CHECK: and i1 [[COND:%.*]], [[COND]]{{$}} +; CHECK: select i1 [[COND]] +define void @test1() !dbg !6 { +start: + %cond = call i1 @make_condition(), !dbg !8 + br i1 %cond, label %then, label %else, !dbg !9 + +then: ; preds = %start + %and = and i1 %cond, %cond, !dbg !10 + br label %else, !dbg !11 + +else: ; preds = %then, %start + %phi = phi i1 [ %cond, %start ], [ %and, %then ], !dbg !12 + ret void, !dbg !13 +} + +!llvm.dbg.cu = !{!0} +!llvm.debugify = !{!3, !4} +!llvm.module.flags = !{!5} + +!0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2) +!1 = !DIFile(filename: "test.ll", directory: "/") +!2 = !{} +!3 = !{i32 6} +!4 = !{i32 0} +!5 = !{i32 2, !"Debug Info Version", i32 3} +!6 = distinct !DISubprogram(name: "test1", linkageName: "test1", scope: null, file: !1, line: 1, type: !7, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2) +!7 = !DISubroutineType(types: !2) +!8 = !DILocation(line: 1, column: 1, scope: !6) +!9 = !DILocation(line: 2, column: 1, scope: !6) +!10 = !DILocation(line: 3, column: 2, scope: !6) +!11 = !DILocation(line: 4, column: 2, scope: !6) +!12 = !DILocation(line: 5, column: 3, scope: !6) +!13 = !DILocation(line: 6, column: 3, scope: !6)