[PATCH] D97495: [SimplifyCFG] avoid illegal phi with both poison and undef

[Juneyoung Lee via Phabricator via llvm-commits]

aqjune added a comment.

What about updating redirectValuesFromPredecessorsToPhi to lower conflicting poison to undef?
We can maintain two sets of incoming BBs, say BBundef and BBpoison that have poison incoming values and undef incoming values.
At the end of redirectValuesFromPredecessorsToPhi, if BBundef and BBpoison overlaps, there are operands that need to be updated.
It will keep the transformation enabled.


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https://reviews.llvm.org/D97495