[PATCH] D57789: [CGP] form usub with overflow from sub+icmp

[Dave Green via Phabricator via llvm-commits]

dmgreen added a comment.

Hello. I ran some benchmarks and they were kind of all over the place, but on average a little down. The Arm backend seems to be quite opinionated about the uaddo's, using it's own nodes for a lot of things, so there might be some missing parts. There were enough ups in there to make us think that this can be good (and can show areas of improvement like in D57833 <https://reviews.llvm.org/D57833>), but we may need a few fixes first. Putting it behind a target hook in the meantime whilst we take a look does sound sensible.

I haven't ran any AArch64 tests, just Arm (we had some infrastructure failures that need some emergency fixes). It may be better there already.


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https://reviews.llvm.org/D57789