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

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri marked an inline comment as done.
lebedev.ri added inline comments.


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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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RKSimon wrote:
> Do we actually need to do a costly popcnt? Are we doing anything other than checking for zero / allones?
This whole logic is structured around the fact that we might only insert *some* elements.


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https://reviews.llvm.org/D137913