RFR: 8315856: RISC-V: Use Zacas extension for cmpxchg

[Robbin Ehn]

On Thu, 30 Nov 2023 17:48:11 GMT, Ludovic Henry <luhenry at openjdk.org> wrote:

> 8315856: RISC-V: Use Zacas extension for cmpxchg

I this was what I think we had somewhere :)

src/hotspot/cpu/riscv/macroAssembler_riscv.cpp line 2645:

> 2643: 
> 2644:     bind(nope);
> 2645:     membar(AnyAny);

Suggestion:

src/hotspot/cpu/riscv/macroAssembler_riscv.cpp line 2647:

> 2645:     membar(AnyAny);
> 2646:   }
> 2647: 

Suggestion:

    membar(AnyAny);

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PR Review: https://git.openjdk.org/jdk/pull/16910#pullrequestreview-1774842971
PR Review Comment: https://git.openjdk.org/jdk/pull/16910#discussion_r1422286487
PR Review Comment: https://git.openjdk.org/jdk/pull/16910#discussion_r1422286394