[PATCH] D69127: [DAGCombiner] widen zext of popcount based on target support

[Jinsong Ji via Phabricator via llvm-commits]

jsji added a comment.

Yeah.

I am asking because I see we will use `any_extend` with the simple call.

  define i8 @popz_i8_i8(i8 %x) {
    %pop = tail call i8 @llvm.ctpop.i8(i8 %x)
    ret i8 %pop
  }

widening in this example might not get a perf gain, 
but I think in some case we might win, at least not loss?

And since you mention this is a prerequisite for canonicalizing,
so maybe that will bring more possibility of win?


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  https://reviews.llvm.org/D69127/new/

https://reviews.llvm.org/D69127