RFR: 8373069: RISC-V: implement GHASH intrinsic [v4]

[Feilong Jiang]

On Thu, 11 Dec 2025 12:22:13 GMT, Anjian Wen <wenanjian at openjdk.org> wrote:

>> support GHASH intrinsic for crypt GCM, which need zvkg extension. 
>> 
>> passed the tests in 
>> test/hotspot/jtreg/compiler/codegen/aes/
>> test/jdk/com/sun/crypto
>
> Anjian Wen has updated the pull request incrementally with one additional commit since the last revision:
> 
>   modify format

src/hotspot/cpu/riscv/stubGenerator_riscv.cpp line 3019:

> 3017:     assert(UseGHASHIntrinsics, "Must be");
> 3018:     assert(UseZvbb, "need Zvbb extension support");
> 3019:     assert(UseZvkg, "need GHASH instructions (Zvkg extension) support");

Do we need `UseZvbb` and  `UseZvkg` assertions here? `UseGHASHIntrinsics` should be enough as it depends on `UseZvbb` and  `UseZvkg`.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28548#discussion_r2616696345