[PATCH] D59535: [SelectionDAG] Compute known bits of CopyFromReg

[Piotr Sobczak via Phabricator via llvm-commits]

piotr added a comment.

It's indeed unfortunate that you saw a regression with my patch. The patch makes SelectionDAG see more context, so it provides more optimization opportunities. Arguably, the fact that you see worse code now is a limitation of the optimization you mentioned that has become visible only now. Have you checked whether the problematic opt could be restricted (possibly only on targets not benefiting from the broader scope of the SelectionDAG)?


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  rL LLVM

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  https://reviews.llvm.org/D59535/new/

https://reviews.llvm.org/D59535