RFR: 8352218: RISC-V: Zvfh requires RVV

[Hamlin Li]

On Tue, 18 Mar 2025 09:04:07 GMT, Robbin Ehn <rehn at openjdk.org> wrote:

> Hi please consider.
> 
> Added case to turn off UseZvfh when no RVV. 
> Which is the cause of the test issues, zvfh on but no rvv.
> 
> Also made all case identical and added no warning when default.
> Move them to the common init, as the "UseExtension" is not C2 specific.
> 
> Manual tested and some random compiler tests.
> 
> Thanks, Robbin

Looks good. Thanks!

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Marked as reviewed by mli (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/24094#pullrequestreview-2693979228