RFR: 8320646: RISC-V: C2 VectorCastHF2F [v7]

[Hamlin Li]

On Thu, 7 Mar 2024 02:54:43 GMT, Fei Yang <fyang at openjdk.org> wrote:

>> Hamlin Li has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   minor improvements
>
> test/hotspot/jtreg/compiler/vectorization/TestFloatConversionsVector.java line 31:
> 
>> 29:  * @requires (os.simpleArch == "x64" & (vm.cpu.features ~= ".*avx512f.*" | vm.cpu.features ~= ".*f16c.*")) |
>> 30:  *           os.arch == "aarch64" |
>> 31:  *           (os.arch == "riscv64" & vm.cpu.features ~= ".*zvfh.*")
> 
> A small question: I see you used following condition when doing the scalar version:
>     `(os.arch == "riscv64" & vm.cpu.features ~= ".*zfh,.*")`
> There is comma there for matching cpu features. Do we really need this comma? It is not there for this vector version.

Seems not necessary currently, unless in the future there is other extension starting with `zfh`, e.g. `zfhX`, but seems that chance is low IMHO.
And, I think it might not work for the last extension in the CPU feature string if it's with a comma (as the cpu feature string is converted from a list to string, so the last one will not ending with a`,` ? ), so for new and long named extensions, it should be without a comma.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17698#discussion_r1516063293