RFR: 8319781: RISC-V: Refactor UseRVV related checks [v3]

[Hamlin Li]

On Mon, 13 Nov 2023 15:25:31 GMT, Fei Yang <fyang at openjdk.org> wrote:

>> I'm not sure, as there are some code in share/classfile/vmIntrinsics.cpp which depends on SpecialEncodeISOArray's value:
>> 
>>   case vmIntrinsics::_encodeISOArray:
>>   case vmIntrinsics::_encodeAsciiArray:
>>   case vmIntrinsics::_encodeByteISOArray:
>>     if (!SpecialEncodeISOArray) return true;
>>     break;
>
> The reason is that `SpecialEncodeISOArray` is a DIAGNOSTIC option which I think is for debugging / trouble-shooting purpose. The other four ones are `SpecialStringCompareTo`, `SpecialStringIndexOf`, `SpecialStringEquals` and `SpecialArraysEquals`. So this code snippet checking for `SpecialEncodeISOArray` is in function `vmIntrinsics::disabled_by_jvm_flags`. So I think we are safe to have this change. In fact, `SpecialEncodeISOArray` and the others are not checked or modified by other platforms either.

It makes sense, Thanks!

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/16580#discussion_r1391368835