RFR: 8343600: RISC-V: enable CRC32 intrinsic when either Zba or RVV are supported

[Hamlin Li]

On Wed, 6 Nov 2024 03:42:42 GMT, Fei Yang <fyang at openjdk.org> wrote:

> Just tried on one of my OoO riscv64 machines (One which is not equipped with Zba). The performance data still looks fine. I also witnessed that the B-extension is becoming popular on new hardwares (BPI-F3, HiFive P550, etc). So I think we can just eliminate this dependence on Zba.

Great! Thanks for testing!

Are these machines with or without RVV? As either RVV and Zba can improvement the performance when the data size is big. So to remove it, it might be safer for us to make sure when both RVV and Zba are not supported, we still get no performance regression when data size is big.

And seems the test data above also show a little regression when size is 65536, and the trend shows it will get bigger when data size get bigger than 65536.

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PR Comment: https://git.openjdk.org/jdk/pull/21897#issuecomment-2459081257