diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp @@ -2957,10 +2957,13 @@ if (&BonusInst == Cond) CondInPred = NewBonusInst; - // When we fold the bonus instructions we want to make sure we - // reset their debug locations in order to avoid stepping on dead - // code caused by folding dead branches. - NewBonusInst->setDebugLoc(DebugLoc()); + if (PBI->getDebugLoc() != NewBonusInst->getDebugLoc()) { + // Unless the instruction has the same !dbg location as the original + // branch, drop it. When we fold the bonus instructions we want to make + // sure we reset their debug locations in order to avoid stepping on + // dead code caused by folding dead branches. + NewBonusInst->setDebugLoc(DebugLoc()); + } RemapInstruction(NewBonusInst, VMap, RF_NoModuleLevelChanges | RF_IgnoreMissingLocals); diff --git a/llvm/test/Transforms/SimplifyCFG/fold-debug-location.ll b/llvm/test/Transforms/SimplifyCFG/fold-debug-location.ll --- a/llvm/test/Transforms/SimplifyCFG/fold-debug-location.ll +++ b/llvm/test/Transforms/SimplifyCFG/fold-debug-location.ll @@ -1,6 +1,7 @@ ; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 < %s | FileCheck %s --match-full-lines ; Make sure we reset the debug location when folding instructions. +; CHECK-LABEL: define {{.+}} @patatino({{.+}} ; CHECK: [[VAL:%.*]] = and i32 %c2, %k ; CHECK-NEXT: [[VAL2:%.*]] icmp eq i32 [[VAL]], 0 @@ -24,6 +25,37 @@ ret i32 undef, !dbg !16 } + +; All instructions involved in folding have the same !dbg location. Make sure +; they are preserved. +define void @dbg_all_equal(i32 %k, i32 %c1, i32 %c2) !dbg !17 { +; CHECK-LABEL: define {{.+}} @dbg_all_equal({{.+}} +; CHECK-NEXT: [[A1:%[a-z0-9]+]] = and i32 %c1, %k, !dbg [[DBG:![0-9]+]] +; CHECK-NEXT: [[C1:%[a-z0-9]+]] = icmp eq i32 [[A1]], 0, !dbg [[DBG]] +; CHECK-NEXT: [[A2:%[a-z0-9]+]] = and i32 %c2, %k, !dbg [[DBG]] +; CHECK-NEXT: [[C2:%[a-z0-9]+]] = icmp eq i32 [[A2]], 0, !dbg [[DBG]] +; CHECK-NEXT: [[OR:%[.a-z0-9]+]] = or i1 [[C1]], [[C2]], !dbg [[DBG]] +; CHECK-NEXT: br i1 [[OR]], label {{.+}}, label {{.+}}, !dbg [[DBG]] +; + %1 = and i32 %c1, %k, !dbg !18 + %2 = icmp eq i32 %1, 0, !dbg !18 + br i1 %2, label %8, label %3, !dbg !18 + +3: + %4 = and i32 %c2, %k, !dbg !18 + %5 = icmp eq i32 %4, 0, !dbg !18 + br i1 %5, label %8, label %6, !dbg !18 + +6: + %7 = tail call i32 (...) @bar(), !dbg !18 + br label %8, !dbg !18 + +8: + ret void +} + + + !llvm.dbg.cu = !{!0} !llvm.debugify = !{!3, !4} !llvm.module.flags = !{!5} @@ -45,3 +77,5 @@ !14 = !DILocation(line: 7, column: 1, scope: !6) !15 = !DILocation(line: 8, column: 1, scope: !6) !16 = !DILocation(line: 9, column: 1, scope: !6) +!17 = distinct !DISubprogram(name: "dbg_all_equal", linkageName: "dbg_all_equal", scope: null, file: !1, line: 1, type: !7, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2) +!18 = !DILocation(line: 10, column: 10, scope: !17)