[PATCH] D89381: [SCEV] Re-enable "Use nw flag and symbolic iteration count to sharpen ranges of AddRecs", attempt 3

Wed Oct 21 05:03:38 PDT 2020

fhahn added a comment.

In D89381#2344230 <https://reviews.llvm.org/D89381#2344230>, @mkazantsev wrote:

> In D89381#2344217 <https://reviews.llvm.org/D89381#2344217>, @fhahn wrote:
>
>> In D89381#2344199 <https://reviews.llvm.org/D89381#2344199>, @mkazantsev wrote:
>>
>>> Now isKnownPredicateViaConstantRanges is used for TODO check too, and Step is limited to the constant. If it still is not helping, then I have no slightest clue what it can be and need a reproducer for the problem.
>>
>> From what I understand the revert commit specifically mentioned a large (+3%) regression in compile-time for mafft from CTMark, which is part of llvm-test-suite, built with -O3. And in particular mentioned a larger regression in a specific file of mafft (partSalignmm.c). IIUC it should be possible to reproduce the regression by building that file with -O3 for X86 with release builds (no assertions) with and without the change?
>
> I don't have it in my tree; is it https://github.com/llvm/llvm-test-suite/tree/master/CTMark what you are referencing? I can try this one...

Yes, it's part of the separate llvm-test-suite repo, the sources for mafft specifically are here https://github.com/llvm/llvm-test-suite/tree/master/MultiSource/Benchmarks/mafft. The `CTMark` directory only contains links to the actual sources, because it is only a small subset targeted at tracking compile-time.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D89381/new/

https://reviews.llvm.org/D89381