[PATCH] D68930: [InstCombine] Shift amount reassociation in shifty sign bit test (PR43595)

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In D68930#1714856 <https://reviews.llvm.org/D68930#1714856>, @xbolva00 wrote:

> >> sadly i'm still seeing regressions (although smaller!) in target benchmark, and analysis of IR points to *this* missing pattern
>
> But does this or base pattern shows up somewhere else (test suite/clang/chromium) than in your benchmark?


It's not "'your benchmark'", that is a real code. I'm not pulling it out of a thin air.

> I think this is very rare pattern and it is not very good that we are going to add another rare pattern to InstCombine which is a slow pass already. I still think AggresiveInstCombine is better solution - or improve your code of interest manually.


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