RFR: 8345322: RISC-V: Add concurrent gtests for cmpxchg variants [v4]

[Robbin Ehn]

On Wed, 11 Dec 2024 11:20:05 GMT, Fei Yang <fyang at openjdk.org> wrote:

>> Robbin Ehn has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Inclusive case
>
> test/hotspot/gtest/riscv/test_assembler_riscv.cpp line 296:
> 
>> 294:   bool zacas = UseZacas;
>> 295:   UseZacas = false;
>> 296:   run_plain_cmpxchg_tests<uint32_t, Assembler::uint32>();
> 
> Not quite sure if we should cover `uint32` type here. `lr.w` used to implement the CAS operation loads a 32-bit word and sign-extend it.

As passing uint32 as operand size is supported and done by compareAndSwapNNode.
So we should test it ?

Which also says we should add test with max and min size of TESTSIZE, fixing that.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22574#discussion_r1880286352