RFR: 8312425: [vectorapi] AArch64: Optimize vector math operations with SLEEF [v4]

[Magnus Ihse Bursie]

On Fri, 15 Mar 2024 13:58:05 GMT, Hamlin Li <mli at openjdk.org> wrote:

>> Hi,
>> Can you help to review this patch?
>> Thanks
>> 
>> This is a continuation of work based on [1] by @XiaohongGong, most work was done in that pr. In this new pr, just rebased the code in [1], then added some minor changes (renaming of calling method, add libsleef as extra lib in CI cross-build on aarch64 in github workflow); I aslo tested the combination of following scenarios:
>> * at build time
>>   * with/without sleef
>>   * with/without sve support 
>> * at runtime
>>   * with/without sleef
>>   * with/without sve support 
>> 
>> [1] https://github.com/openjdk/jdk/pull/16234
>> 
>> ## Regression Test
>> * test/jdk/jdk/incubator/vector/
>> * test/hotspot/jtreg/compiler/vectorapi/
>> 
>> ## Performance Test
>> Previously, @XiaohongGong has shared the data: https://github.com/openjdk/jdk/pull/16234#issuecomment-1767727028
>
> Hamlin Li has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fix jni includes

First of all, building stuff with `--with-extra-cflags` is always at your own peril. It might, or might not, work, partially due to problems such as the one you describe, where the user-added flag somehow conflicts with the existing flag. If you wish to modify the build in ways that is not compatible with the existing build logic, you might end up needed a local patch to be applied, and not just adding the  `--with-extra-cflags` command line.

With that said, we will try to make it as possible as reasonable to write the build system for flexibility.

In this case: what do you propose we would have done instead? My understanding is that the compiler needs to be told about SVE in order to compile libsleef properly.

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PR Comment: https://git.openjdk.org/jdk/pull/18294#issuecomment-2489025971