RFR: 8345322: RISC-V: Add concurrent gtests for cmpxchg variants [v2]

[Robbin Ehn]

On Wed, 11 Dec 2024 03:09:25 GMT, Fei Yang <fyang at openjdk.org> wrote:

>> Robbin Ehn has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:
>> 
>>  - Code share
>>  - Overflow
>>  - Merge branch 'master' into 8345322
>>  - Concurrent
>
> test/hotspot/gtest/riscv/test_assembler_riscv.cpp line 355:
> 
>> 353:   TESTSIZE diff = std::numeric_limits<TESTSIZE>::max() - now;
>> 354:   add -= diff;
>> 355:   return std::numeric_limits<TESTSIZE>::min() + add;
> 
> For int8_t, `next_count(127, 1)` returns -127. Is this expected? Shouldn't we get -128 after the wrap around?

Yes, you are correct. Forgot to subtract one for the wrap around count.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22574#discussion_r1879513125