[PATCH] D38313: [InstCombine] Introducing Aggressive Instruction Combine pass
Sanjay Patel via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Wed Dec 20 12:59:17 PST 2017
spatel added a comment.
In https://reviews.llvm.org/D38313#960502, @craig.topper wrote:
> @spatel, what do you think about vector types here?
I’m not at a dev machine, so I can’t try any experiments. But we’ve had something like this question come up in one of my vector cmp + select patches. Ideally, we’d always shrink those as we do with scalars, but as noted, we may not have good backend support to undo the transform. Given that it’s not a clear win, I think it’s best to limit the vector transforms in this initial patch. Then, we can enable those in a follow-up patch if there are known wins and deal with any regressions without risking the main (?) scalar motivating cases.
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