RFR: 8349582: APX NDD code generation for OpenJDK [v14]

[Jatin Bhateja]

On Thu, 13 Mar 2025 17:50:20 GMT, Srinivas Vamsi Parasa <sparasa at openjdk.org> wrote:

>> The goal of this PR is to generate x86 code using Intel Advanced Performance Extensions (APX) instructions which doubles the number of general-purpose registers, from 16 to 32. Intel APX adds nondestructive destination (NDD) and no flags (NF) flavor for the scalar instructions through EVEX encoding.
>> 
>> For more information about APX, see https://www.intel.com/content/www/us/en/developer/articles/technical/advanced-performance-extensions-apx.html.
>
> Srinivas Vamsi Parasa has updated the pull request incrementally with one additional commit since the last revision:
> 
>   add comments for encoding and UCF

LGTM, 

Please file a JBS on future modification in assembler layer for EEVEX to REX/REX2 encoding and append to this PR before committing.

Thanks.

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Marked as reviewed by jbhateja (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/23501#pullrequestreview-2682967777