[PATCH] D87772: [SLP] sort candidates to increase chance of optimal compare reduction

[Alexey Bataev via Phabricator via llvm-commits]

ABataev added inline comments.


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Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:6944
       }
       i += ReduxWidth;
       ReduxWidth = PowerOf2Floor(NumReducedVals - i);
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Maybe, better to change this expression too? The main problem here is that the sliding window has step `ReduxWidth`. Maybe, use `1` here in common case? Also, I don't think sorting is safe here. It is better to keep the original order of the instructions, but pre-select only the matching ones.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D87772/new/

https://reviews.llvm.org/D87772