[PATCH] D93888: [GVN] If zext X == N or sext X == N, then X == trunc N.

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In D93888#2483368 <https://reviews.llvm.org/D93888#2483368>, @wecing wrote:

>> For NewGVN and IPSCCP PredicateInfo would have to handle it, and I'm pretty sure we want to avoid that.
>
> @nikic Would you mind explaining why? If there is a good reason we cannot do this in NewGVN then D93850 <https://reviews.llvm.org/D93850> might be the best we could do.

I'm not yet convinced we can do this in instcombine,
because why can we do this without a profitability check,
like the fold just below that one does?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D93888/new/

https://reviews.llvm.org/D93888