RFR: 8355654: RISC-V: Relax register constraint for some vector-scalar instructions [v4]

[Fei Yang]

On Mon, 28 Apr 2025 08:49:54 GMT, Gui Cao <gcao at openjdk.org> wrote:

>> Hi, here we separate src from dst_src to give the compiler a greater degree of flexibility. Note that in the masked version we can't modify it, because we can't change inactive elements in the mask version.
>> 
>> ### Testing
>> qemu-system 9.1.50 with UseRVV:
>> 
>> - [x] Run test/jdk/jdk/incubator/vector (fastdebug)
>
> Gui Cao has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Polishing

Looks fine. Thanks!

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Marked as reviewed by fyang (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/24905#pullrequestreview-2798643117