RFR: 8355563: VectorAPI: Refactor current implementation of subword gather load API

[Xiaohong Gong]

On Mon, 2 Jun 2025 10:48:25 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>>> > @XiaohongGong Thanks for splitting this one out, and for investigating the regressions here.
>>> > Putting the permalink here, fixed to the current change (the link you pasted will always refer to the newest, which may later on point to the wrong line when lines above are inserted / deleted):
>>> > https://github.com/openjdk/jdk/blob/7077535c0b0a6ea0a2a167f9135b1504a3d71fb3/src/hotspot/share/opto/loopnode.cpp#L1659-L1661
>>> > 
>>> > I wonder if we should just use `Node::uncast` there? But I'm quite unsure about that.
>>> 
>>> Sounds good to me. I will have a deep investigation for it. Thanks!
>> 
>> Hi @eme64  @jatin-bhateja,  I'v created a PR https://github.com/openjdk/jdk/pull/25539 to fix this issue. With this change, the performance regression can be fixed as well.  Could you please take a look at that change and help to run the test on different X86 machines?   Thanks a lot!
>
> @XiaohongGong I reviewed https://github.com/openjdk/jdk/pull/25539. Since it is a relatively simple patch, I suggest that we integrate that one first, and come back to this here later. Is that ok for you?

Hi @eme64 I'v updated the patch to fix the comment issue you pointed above. Could you please help take a look at again? Thanks a lot!

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PR Comment: https://git.openjdk.org/jdk/pull/25138#issuecomment-3004029058