[PATCH] D85446: [InstCombine] Add vector support to mul(add(x,c),negpow2) -> mul(sub(-c,x),pow2) folds

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In D85446#2205616 <https://reviews.llvm.org/D85446#2205616>, @bjope wrote:

> (Just some heads up, in case someone else got the same problem...)
>
> I've noticed some regressions downstream after this patch. Haven't debugged/reduced it completely yet, but at least in one case I suspect that the problem actually might be in load-store-vectorizer.
>
> Used to get something like this before load-store-vectorizer:
>
> <...>
>
> The old input to load-store-vectorizer resulted in two <8 x i16> loads, but the new input gives one <8 x i16 load, two <2 x i16> loads and one <4 x i16> load. So for some reason LSV fails to detect that the loads are consecutive given the new IR. At least that is my current theory.

Please can you file a bug with reproducer?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D85446/new/

https://reviews.llvm.org/D85446