[PATCH] D137913: [X86] Rewrite `getScalarizationOverhead()`

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added a comment.

Sorry - running out of time, I'll have to come back to this tomorrow



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Comment at: llvm/lib/Target/X86/X86TargetTransformInfo.cpp:4440
+          APInt LaneEltMask = WidenedDemandedElts.extractBits(Scale, Scale * I);
+          unsigned Population = LaneEltMask.countPopulation();
+          bool SubvectorIsAffected = Population > 0;
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Do we actually need to do a costly popcnt? Are we doing anything other than checking for zero / allones?


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  https://reviews.llvm.org/D137913/new/

https://reviews.llvm.org/D137913