RFR: 8355699: RISC-V: support SUADD/SADD/SUSUB/SSUB [v2]

[Hamlin Li]

On Tue, 6 May 2025 10:39:04 GMT, Fei Yang <fyang at openjdk.org> wrote:

> Updated change looks good.

Thank you!

> What about the vector-scalar variants (vsaddu.vx, vsaddu.vi, etc.)? Do they help in any way?

I think so, although not sure how much benefit it will bring, as it should be able to do a vmv first, then use the instructs in this patch, so there should be some improvement, but maybe just minor one.
And for other operations, like (signed/unsigned) max/min, mulb/s/i/l/f/d, and so on, I think we can also introduce the _vx and _vi version.
Maybe we could implement these bunch of instructs in another patch together?

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PR Comment: https://git.openjdk.org/jdk/pull/25005#issuecomment-2854193307