RFR: 8295948: Support for Zicbop/prefetch instructions on RISC-V

[Ludovic Henry]

On Thu, 27 Oct 2022 15:18:02 GMT, Ludovic Henry <luhenry at openjdk.org> wrote:

> The OpenJDK supports generating prefetch instructions on most platforms. RISC-V supports through the Zicbop extension the use of prefetch instructions. We want to make sure we use these instructions whenever they are available.
> 
> It passes `hotspot:tier1` test suite

@RealFYang let me know what you think. Thanks!

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PR: https://git.openjdk.org/jdk/pull/10884