RFR: 8349721: Add aarch64 intrinsics for ML-KEM [v7]

[Andrew Dinn]

On Thu, 10 Apr 2025 13:19:05 GMT, Ferenc Rakoczi <duke at openjdk.org> wrote:

>> By using the aarch64 vector registers the speed of the computation of the ML-KEM algorithms (key generation, encapsulation, decapsulation) can be approximately doubled.
>
> Ferenc Rakoczi has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Code rearrange, some renaming, fixing comments
>  - Changes suggested by Andrew Dinn.

src/hotspot/cpu/aarch64/stubGenerator_aarch64.cpp line 5690:

> 5688:     kyber_montmul32(vs1, vs3, vc, vs2, vq);
> 5689:     // store the four results as two interleaved pairs of
> 5690:     // quadwords

Suggestion:

    // store back the two pairs of result vectors de-interleaved as 8H elements
    // i.e. storing each pairs of shorts striped across a register pair adjacent
    // in memory

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PR Review Comment: https://git.openjdk.org/jdk/pull/23663#discussion_r2044745249