[PATCH] D36172: [InstCombine] Improve profitability check for folding PHI args

[Ulrich Weigand via Phabricator via llvm-commits]

uweigand added a comment.

The testcase is extracted from a real-word program.  On that program, the transformation (moving some of those operations out of a hot loop) is a significant overall win (about 10% improved performance of the whole program).  I agree that this application is a quite special case -- this patch doesn't make much difference to the overall performance of the platform in general.

Agreed that the overall InstCombine algorithm can exhibit performance issues, and should probably be replaced in the long term.  But I don't think this particular patch makes those issues significantly worse :-)


https://reviews.llvm.org/D36172