[PATCH] D32451: Improve profile-guided heuristics to use estimated trip count.

Teresa Johnson via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Mon Jun 19 06:01:03 PDT 2017


tejohnson accepted this revision.
tejohnson added a comment.
This revision is now accepted and ready to land.

In https://reviews.llvm.org/D32451#783559, @twoh wrote:

> @tejohnson Sorry for the late reply. I was out of internet for days. I have no objection to set the default value to true, but prefer to have it as a separate patch so that we can track the impact on performance of each chance more easily.


Sounds good, that would be great to switch to true as a follow on patch. Looks like the comment that used to explain why this was off by default shouldn't apply anymore. Which leads me to one request before submitting, noted below.

Since multiple people have lgtm'ed this on phab and/or the mailing list, I am marking this accepted in phab.



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Comment at: lib/Transforms/Vectorize/LoopVectorize.cpp:7911
   const BranchProbability ColdProb(1, 5); // 20%
   ColdEntryFreq = BlockFrequency(BFI->getEntryFreq()) * ColdProb;
 
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Please remove the above code to compute and set ColdEntryFreq, which can also be removed from the LoopVectorizePass struct.


https://reviews.llvm.org/D32451





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