RFR: 8312425: [vectorapi] AArch64: Optimize vector math operations with SLEEF [v2]

[Andrew Haley]

On Fri, 5 Apr 2024 12:17:17 GMT, Hamlin Li <mli at openjdk.org> wrote:

>> Hi,
>> Can you help to review the patch?
>> This pr is based on previous work and discussion in [pr 16234](https://github.com/openjdk/jdk/pull/16234), [pr 18294](https://github.com/openjdk/jdk/pull/18294).
>> 
>> Compared with previous prs, the major change in this pr is to integrate the source of sleef (for the steps, please check `src/jdk.incubator.vector/linux/native/libvectormath/README`), rather than depends on external sleef things (header or lib) at build or run time.
>> Besides of this change, also modify the previous changes accordingly, e.g. remove some uncessary files or changes especially in make dir of jdk.
>> 
>> Besides of the code changes, one important task is to handle the legal process.
>> 
>> Thanks!
>
> Hamlin Li has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - disable unused-function warnings; add log msg
>  - minor

> Nice work, Hamlin and Xiaohong. I'm glad to see progress on incorporating SLEEF library into the JDK. (Somehow I > From engineering perspective, I believe that bundling vector math library with the JDK is the right thing to do, but it doesn't imply the sources should be part of JDK. There are already examples of optional dependencies on external native libraries in HotSpot (e.g., hsdis tool w/ binutils, capstone, and llvm backends).

No, it doesn't imply that the sources should be part of JDK, but practical reasons to do with the way that OpenJDK is built and shipped by various parties strongly suggests that we should integrate the SLEEF library into the JDK source tree. If we don't, there will be skew between OpenJDK versions shipped by different vendors. Also, I believe that there is less work for all of us if we integrate rather than having communicate to everyone building the JDK. And finally, Mark Reinhold has stated that the JDK is not downstream of any other project.

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PR Comment: https://git.openjdk.org/jdk/pull/18605#issuecomment-2049256172