[PATCH] D119105: [DAGCombiner][AArch64] Enhance to fold CSNEG into CSINC instruction

[Dave Green via Phabricator via llvm-commits]

dmgreen added a comment.

Hmm. I feel like it shares more code than it needs special cases? Maybe try and give it a go, and we can see if it looks too bad.

(I had in the past had the idea of removing AArch64ISD::CSNEG/CSINC/CSINV - they are mostly used only for constants as far as I understand and could just as well use CSEL directly. Either that or make sure of them more, canonicalizing more patterns to use them. I don't know what the tradeoffs of those are though. Less target dependant nodes can be a good thing, but more aggressively targeting the nodes we have as opposed to leaving it to chance may be good too. That's just an aside though).


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  https://reviews.llvm.org/D119105/new/

https://reviews.llvm.org/D119105