RFR: 8351949: RISC-V: Cleanup and enable store-load peephole for membars [v8]

[Robbin Ehn]

On Wed, 2 Apr 2025 13:17:02 GMT, Hamlin Li <mli 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 11 additional commits since the last revision:
>> 
>>  - Merge branch 'master' into tso-merge
>>  - Merge branch 'master' into tso-merge
>>  - format comment
>>  - Merge branch 'master' into tso-merge
>>  - Review comments
>>  - Merge branch 'master' into tso-merge
>>  - Review comments
>>  - Fixed ws
>>  - Revert NC
>>  - Fixed comment
>>  - ... and 1 more: https://git.openjdk.org/jdk/compare/d83e8386...c2688a6a
>
> src/hotspot/cpu/riscv/riscv.ad line 7951:
> 
>> 7949: %}
>> 7950: 
>> 7951: instruct unnecessary_membar_volatile_rvtso() %{
> 
> This one could be merged with `unnecessary_membar_volatile_rvwmo`, and remove the `UseZtso` in predicate.

There are several more which can be merge, such as membar_volatile_rvXX.
But I prefered having those for rvtso in one section and those for rvwmo in another section.
That is not a good approach?

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/24035#discussion_r2026291366