RFR: 8370691: Add new Float16Vector type and enable intrinsification of vector operations supported by auto-vectorizer [v7]

[Jatin Bhateja]

On Wed, 10 Dec 2025 10:23:30 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Add a new  Float16lVector type and corresponding concrete vector classes, in addition to existing primitive vector types, maintaining operation parity with the FloatVector type.
>> - Add necessary inline expander support.
>>    - Enable intrinsification for a few vector operations, namely ADD/SUB/MUL/DIV/MAX/MIN/FMA.
>> - Use existing Float16 vector IR and backend support.
>> - Extended the existing VectorAPI JTREG test suite for the newly added Float16Vector operations.
>>  
>> The idea here is to first be at par with Float16 auto-vectorization support before intrinsifying new operations (conversions, reduction, etc).
>> 
>> The following are the performance numbers for some of the selected Float16Vector benchmarking kernels compared to equivalent auto-vectorized Float16OperationsBenchmark kernels.
>> 
>> <img width="1344" height="532" alt="image" src="https://github.com/user-attachments/assets/c8157c3c-22b0-4bc1-9de9-7a68cadb7b2a" />
>> 
>> Initial RFP[1] was floated on the panama-dev mailing list.
>> 
>> Kindly review the draft PR and share your feedback.
>> 
>> Best Regards,
>> Jatin
>> 
>> [1] https://mail.openjdk.org/pipermail/panama-dev/2025-August/021100.html
>
> Jatin Bhateja has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 20 commits:
> 
>  - Merge branch 'master' of http://github.com/openjdk/jdk into JDK-8370691
>  - Optimizing tail handling
>  - Merge branch 'master' of http://github.com/openjdk/jdk into JDK-8370691
>  - Cleanups
>  - Fix failing jtreg test in CI
>  - Merge branch 'master' of http://github.com/openjdk/jdk into JDK-8370691
>  - Cleanups
>  - Adding support for custom basic  type T_FLOAT16, passing BasicType lane types to inline expander entries
>  - Cleaning up interface as per review suggestions
>  - Some cleanups
>  - ... and 10 more: https://git.openjdk.org/jdk/compare/b60ac710...44ac727d

> jdk/incubator/vector/Float16Vector512Tests.java



> This patch results in two of the JTREG tests failing on aarch64 machines-
> 
> ```
> jdk/incubator/vector/Float16Vector512Tests.java
> compiler/vectorapi/TestFloat16VectorOperations.java
> ```
> 
> which is due to an issue in the `aarch64.ad` file. Fixed the failures and also added aarch64 specific IR rules which were missing for some of the tests in the `compiler/vectorapi/TestFloat16VectorOperations.java` test.
> 
> @jatin-bhateja Could you please add the attached fix to this patch? Thanks! [fix.patch](https://github.com/user-attachments/files/24076067/fix.patch)

Hi @Bhavana-Kilambi , Thanks for running this thorugh your setup, I am also able to reproduce it on Google AXION, your fix fills the gap in instruction selector, I suggest creating a seperate PR for this ? You can either create a smaller standalone reproducer testcase or mention about the tests part of this PR.

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PR Comment: https://git.openjdk.org/jdk/pull/28002#issuecomment-3640370652