[PATCH] D75689: [VectorCombine] fold extract-extract-op with different extraction indexes

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

In D75689#1927928 <https://reviews.llvm.org/D75689#1927928>, @jgorbe wrote:

> Thanks for the note about the flags. We have tried both of them, and any (or both) of them being present causes the regression to go away, so that unblocks us while we work on producing a proper test case.


Sounds good. Note that "-disable-vector-combine" is the big hammer; it effectively disables this entire pass. 
If the regressions only appeared with this patch and go away with "-disable-binop-extract-shuffle", the most likely source of the problem is the cost model or this pass is interacting badly with the SLP vectorizer.


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