RFR: 8323116: [REDO] Computational test more than 2x slower when AVX instructions are used [v4]

[Quan Anh Mai]

On Fri, 5 Apr 2024 06:14:57 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> This change modifies the defined behaviours of `cvtss2sd`. Without AVX, it would retains the bits 64-127 of `dst` while with it the bits would be copied from `src`. I would suggest separating the matching rules instead.
>
> Its a cleaver trick to dodge false dependency without compromising on correctness.

@jatin-bhateja I get it but IMO it shouldn't be the responsibility of the assembler to do that, the assembler should emit machine code in a manner that respects what is being written.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18503#discussion_r1553028424