[PATCH] D105392: [InstCombine] Add optimization to prevent poison from being propagated.

[Hyeongyu Kim via Phabricator via llvm-commits]

hyeongyukim marked 2 inline comments as done.
hyeongyukim added inline comments.


================
Comment at: llvm/lib/Transforms/InstCombine/InstructionCombining.cpp:3537
 
-      auto *MaybePoisonUse = MaybePoisonOperand.getValue();
-      auto *FrozenMaybePoisonOperand = new FreezeInst(MaybePoisonUse->get(), MaybePoisonUse->getUser()->getName() + ".fr");
+  if (!OrigOpInst->hasOneUse() ||
+      canCreateUndefOrPoison(dyn_cast<Operator>(OrigOp)))
----------------
lebedev.ri wrote:
> I think it would be good to have a comment explaining why we don't do this iff the `OrigOpInst` has other uses.
> We could just change them all to use `OrigFI` first. Why do we want to not do this?
I add an example of a problem that occurs when there is more than one use of OrigOpInst.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D105392/new/

https://reviews.llvm.org/D105392