[PATCH] D147557: [SCEV] Improve AddRecs' range computation

[Nikita Popov via Phabricator via llvm-commits]

nikic added a comment.

In D147557#4250538 <https://reviews.llvm.org/D147557#4250538>, @mkazantsev wrote:

> LG, but let's wait few days in case if anyone else has concerns/objections.
>
> It would also be great if we could find a way to do it w/o expensive sharpening. There are usually several ways to achieving the same effect.
>
> @aleksandr.popov during this chill period, could you please try to construct a test that shows benefit from your patch w/o expensive sharpening?

The changed code is only used by expensive sharpening, so no :)

I tried applying loop guards to other places like getRangeForAffineAR() as well, but this again had very bad compile-time impact: https://llvm-compile-time-tracker.com/compare.php?from=2caaec65c04ea7d0e9568b7895b7a46d6100cb75&to=87d1063758a038ffa7a0e358dc97c16ef6297aa3&stat=instructions:u Here's the corresponding diff: https://github.com/llvm/llvm-project/commit/87d1063758a038ffa7a0e358dc97c16ef6297aa3 I was hoping that doing this is pretty cheap, but apparently it isn't.


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