RFR: 8365205: C2: Optimize popcount value computation using knownbits [v11]

[Jatin Bhateja]

On Thu, 25 Sep 2025 17:53:48 GMT, Hannes Greule <hgreule at openjdk.org> wrote:

> Looks good to me now, although I'm not exactly sure about the semantics of widen and whether `Type::WidenMax` is the right choice here. Someone else has to look at that.
> 
> Thanks for the work!

Hi @SirYwell ,  Canonicalization normalizes the widen parameter, hence, effective widening will eventually be based on the actual ranges. 

Hi @TobiHartmann  @chhagedorn , can you kindly run this through your testing and share if its good to land in.

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PR Comment: https://git.openjdk.org/jdk/pull/27075#issuecomment-3348126708