RFR: 8329083: RISC-V: Update profiles supported on riscv

[Fei Yang]

On Thu, 4 Apr 2024 09:05:11 GMT, Hamlin Li <mli at openjdk.org> wrote:

>> src/hotspot/cpu/riscv/vm_version_riscv.hpp line 191:
>> 
>>> 189:   #define RV_USE_RVA22U64                            \
>>> 190:     RV_ENABLE_EXTENSION(UseRVC)                      \
>>> 191:     RV_ENABLE_EXTENSION(UseRVV)                      \
>> 
>> Note that V was optional in RVA22U64.
>
> In fact, when I worked on it, I'm bit confused what it should be? including optional or not.
> 
> Peviously, zfh is already enabled by the RVA22U64, but it's optional by [spec](https://github.com/riscv/riscv-profiles/blob/main/profiles.adoc#613-rva22u64-optional-extensions), so I followed this pattern.

Yeah, I think that's a mistake. I don't think it's safe to assume availability of optional extensions. We should only assume mandatory extensions in each profile.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18599#discussion_r1551303147