RFR: 8349686: [s390x] C1: Improve Class.isInstance intrinsic [v2]

[Andrew Haley]

On Tue, 11 Feb 2025 04:14:28 GMT, Amit Kumar <amitkumar at openjdk.org> wrote:

>> s390x implementation for Class.isInstance intrinsic. 
>> 
>> Tier1 test on release & fastdebug vm are clean with flag: `-XX:-UseSecondarySupersCache -XX:+UseSecondarySupersTable -XX:+VerifySecondarySupers -XX:+StressSecondarySupers`. 
>> 
>> Benchmark results will be updated soon.
>
> Amit Kumar has updated the pull request incrementally with one additional commit since the last revision:
> 
>   optimize branching

src/hotspot/cpu/s390/c1_Runtime1_s390.cpp line 639:

> 637:       int i = 0;
> 638:       __ z_stg(Z_tmp_1, (i++)*BytesPerWord + frame::z_abi_160_size, Z_SP);
> 639:       __ z_stg(Z_tmp_2, (i++)*BytesPerWord + frame::z_abi_160_size, Z_SP);

Suggestion:

      __ z_stg(Z_tmp_1, 0*BytesPerWord + frame::z_abi_160_size, Z_SP);
      __ z_stg(Z_tmp_2, 1*BytesPerWord + frame::z_abi_160_size, Z_SP);

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PR Review Comment: https://git.openjdk.org/jdk/pull/23535#discussion_r1950386385