RFR: 8370691: Add new Float16Vector type and enable intrinsification of vector operations supported by auto-vectorizer [v11]

Tue Jan 13 10:27:39 UTC 2026

On Tue, 13 Jan 2026 09:58:29 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 incrementally with one additional commit since the last revision:
> 
>   Adding testpoint for JDK-8373574

src/jdk.incubator.vector/share/classes/jdk/incubator/vector/Float16Vector.java line 1653:

> 1651:      *
> 1652:      * @param e the input scalar
> 1653:      * @return the result of multiplying this vector by the given scalar

The code comment mentions "multiplying", which doesn't seem correct to me. Are we doing any multiplication for min/max?

src/jdk.incubator.vector/share/classes/jdk/incubator/vector/Float16Vector.java line 1694:

> 1692:      *
> 1693:      * @param e the input scalar
> 1694:      * @return the result of multiplying this vector by the given scalar