Allow readonly functions to unwind exceptions. Teach
the optimizers about this. For example, a readonly
function with no uses cannot be removed unless it is
also marked nounwind.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71071 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp
index fea739c..4f2bb1e 100644
--- a/lib/Transforms/Utils/Local.cpp
+++ b/lib/Transforms/Utils/Local.cpp
@@ -164,17 +164,15 @@
// We don't want debug info removed by anything this general.
if (isa<DbgInfoIntrinsic>(I)) return false;
-
- if (!I->mayWriteToMemory())
- return true;
- // Special case intrinsics that "may write to memory" but can be deleted when
- // dead.
+ if (!I->mayHaveSideEffects()) return true;
+
+ // Special case intrinsics that "may have side effects" but can be deleted
+ // when dead.
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I))
// Safe to delete llvm.stacksave if dead.
if (II->getIntrinsicID() == Intrinsic::stacksave)
return true;
-
return false;
}
@@ -230,7 +228,7 @@
SmallPtrSet<PHINode *, 4> PHIs;
PHIs.insert(PN);
for (Instruction *J = cast<Instruction>(*PN->use_begin());
- J->hasOneUse() && !J->mayWriteToMemory();
+ J->hasOneUse() && !J->mayHaveSideEffects();
J = cast<Instruction>(*J->use_begin()))
// If we find a PHI more than once, we're on a cycle that
// won't prove fruitful.