[PATCH] D132261: [SLP]Do not reduce repeated values, use scalar red ops instead.

[Alexey Bataev via Phabricator via llvm-commits]

ABataev added a comment.

In D132261#3821385 <https://reviews.llvm.org/D132261#3821385>, @vdmitrie wrote:

> The patch is seems trying to move SLP vectorizer into InstCombine territory. I'm not sure why we should do that. Did you try to analyze which specific patterns helped in for example GCC-C-execute test?
> Can these represent any cases where instcombine could be improved instead? It is difficult to access this patch based on test changes as a lot of SLP vectorizer tests were not designed as capable to run through instcombine.
> If you run "-instcombine -slp-vectorizer" instead of  just -slp-vectorizer then how many of the affected LIT tests would still benefit from the patch?

Most of these test will be optimized for sure, since they are pretty simple. But looks like there are some other places, where reduction analysis in SLP is better than the similar analysis in instcombiner. Also, if we can do some optimization here, it shall reduce compile time, since instcombiner consumes lots of time


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D132261/new/

https://reviews.llvm.org/D132261