[PATCH] D71164: [InstCombine] Fix infinite loop due to bitcast <-> phi transforms

[Connor Abbott via Phabricator via llvm-commits]

cwabbott added inline comments.


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Comment at: llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp:2321
+    // Make sure the old phis are cleaned up.
+    Worklist.Add(OldPN);
   }
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spatel wrote:
> Can we assert that OldPN has no users at this point?
This isn't true until D71209 lands, and therefore the problem could still happen because `OldPN` won't actually get cleaned up. Even afterwards, there could be a PHI web hanging around. In my patch I assumed that some other dead-code pass would come along and delete it eventually, but I don't know if InstCombine is smart enough to do that before folding the load. Maybe you can just remove all the old phi nodes manually once my patch lands?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D71164/new/

https://reviews.llvm.org/D71164