RFR: 8346664: C2: Optimize mask check with constant offset [v3]

[Matthias Ernst]

On Mon, 27 Jan 2025 07:49:27 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> What's left to do here? Thanks!
>
> @mernst-github Thanks for the test update!
> 
> I see there is still discussion around this line:
> `  return zeros > 0 && ((((jlong)1) << zeros) > mask_t->hi_as_long() && mask_t->lo_as_long() >= 0);`
> 
> It is indeed difficult to read. Maybe even just some clever names of temporary variables could help. But I leave that up to you ;)
> 
> Ping me when you want me to run testing and review again :)

@eme64 After 5+ weeks I'm getting very tired of running after reviewer engagement here. I've been in this business long enough to know that leaving a drive-by comment every few days and kicking the can down the road a little further is a very effective way to signal you're not interested in this contribution. You could have "run testing" a long time ago. If you're overworked, pass it on to a different reviewer but don't string along the contributor. If you care about a contrasting experience, https://github.com/openjdk/jdk/pull/23142 with a much larger design surface took under 2 weeks because of engaged and constructive review. Maybe it might be wise for your group and you to define or revisit goals of engagement.

This is not a pet peeve feature but a really basic performance fix for foreign memory access; I want Panama to be great, but it hurts credibility if getting segment[i+1] right doesn't appear to be a priority.

Feel free to integrate this or hit the close button, I think I've done my due diligence and do not intend to engage on it any further. Thanks.

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PR Comment: https://git.openjdk.org/jdk/pull/22856#issuecomment-2621294029