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

[Florian Hahn via Phabricator via llvm-commits]

fhahn added a comment.

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?


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https://reviews.llvm.org/D89381