[PATCH] D132237: [SDAG] expand is-power-of-2 pattern that uses popcount

[Dave Green via Phabricator via llvm-commits]

dmgreen added reviewers: RKSimon, craig.topper.
dmgreen added a comment.
Herald added a subscriber: StephenFan.

I had almost written something into 57225 that said, effectively, custom isn't a very good costmodel as it can mean so many things, so adding a target hook sounds like a good way forward.

This sounds good for AArch64. Could there be cases where the CTPOP (+setcc) is custom lowered but cheaper than the Add+And+setcc+setcc+and/or? My guess would probably be no, it would either be legal or quite expensive.


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  https://reviews.llvm.org/D132237/new/

https://reviews.llvm.org/D132237