diff options
Diffstat (limited to 'lib/Transforms/Utils/Local.cpp')
| -rw-r--r-- | lib/Transforms/Utils/Local.cpp | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp index 2d43e37..60dc15d 100644 --- a/lib/Transforms/Utils/Local.cpp +++ b/lib/Transforms/Utils/Local.cpp @@ -229,10 +229,10 @@ bool llvm::isInstructionTriviallyDead(Instruction *I) { // We don't want debug info removed by anything this general, unless // debug info is empty. if (DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(I)) { - if (DDI->getAddress()) + if (DDI->getAddress()) return false; return true; - } + } if (DbgValueInst *DVI = dyn_cast<DbgValueInst>(I)) { if (DVI->getValue()) return false; @@ -243,10 +243,16 @@ bool llvm::isInstructionTriviallyDead(Instruction *I) { // Special case intrinsics that "may have side effects" but can be deleted // when dead. - if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) + if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) { // Safe to delete llvm.stacksave if dead. if (II->getIntrinsicID() == Intrinsic::stacksave) return true; + + // Lifetime intrinsics are dead when their right-hand is undef. + if (II->getIntrinsicID() == Intrinsic::lifetime_start || + II->getIntrinsicID() == Intrinsic::lifetime_end) + return isa<UndefValue>(II->getArgOperand(1)); + } return false; } |