RFR: 8351034: Add AVX-512 intrinsics for ML-DSA [v12]

[Sandhya Viswanathan]

On Mon, 31 Mar 2025 14:40:56 GMT, Ferenc Rakoczi <duke at openjdk.org> wrote:

>> By using the AVX-512 vector registers the speed of the computation of the ML-DSA algorithms (key generation, document signing, signature verification) can be approximately doubled.
>
> Ferenc Rakoczi has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Reacting to comments by Volodymyr.

src/hotspot/cpu/x86/stubGenerator_x86_64_sha3.cpp line 359:

> 357:   __ kmovbl(k4, rax);
> 358:   __ addl(rax, 16);
> 359:   __ kmovbl(k5, rax);

We could use the sequence from generate_sha3_implCompress to setup the K registers, that has less dependency:
 
  __ movl(rax, 0x1F);
  __ kmovbl(k5, rax);
  __ kshiftrbl(k4, k5, 1);
  __ kshiftrbl(k3, k5, 2);
  __ kshiftrbl(k2, k5, 3);
  __ kshiftrbl(k1, k5, 4);

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PR Review Comment: https://git.openjdk.org/jdk/pull/23860#discussion_r2023769620