RFR: 8370691: Add new Float16Vector type and enable intrinsification of vector operations supported by auto-vectorizer [v17]

[Emanuel Peter]

On Fri, 23 Jan 2026 04:57:04 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Hi @eme64 , Your comments have been addressed
>
>> @jatin-bhateja This patch is really really large. There are lots of renamings that could be done in a separate patch first (as a subtask). It would make reviewing easier, allowing focus on the substantial work. See discussion here: [#28002 (comment)](https://github.com/openjdk/jdk/pull/28002#discussion_r2705376899)
> 
> Hi @eme64 ,
> 
> I have done some cleanups, following is the summary of changes included with the patch:-
> 
>  ```
>  1 Changes to introduce a new (custom) basictype T_FLOAT16
>         - Global Definition.
>         - Skip over handling where ever applicable.
>   2 Changes to pass laneType (BasicType) to intrinsific entry point instead of element classes.
>        - Inline expander interface changes mainly.
>   3 Changes in abstract and concrete vector class generation templates.
>   4 Changing the nomenclature of Vector classes to avoid Float1664... sort of names...
>   5 Changes in the LaneType to add a new carrier type field.    
>   6 Changes in inline expanders to selectivelty enable intrinsification for opration for which we have
>     auto-vectorization and backend support in place..
>   7 Changes in test generation templates.
>        b. Assert wrappers to conver float16 (short) value to float before invoking testng Asserts.
>        c. Scalar operation wrappers to selectivelty invoke Float16 math routine which are not 
>          part of Java SE math libraries.
>    
>   8 New IR verification test.
>   9 New Micro-benchmark.
>   10 AARCH64 test failure - patch + test fixed by Bhavana Kilambi.  
> 
> 
> Out of above change 7b consumes 40000+ LOC.
> 
> Q. Why do we need wrapper assertions ?
> A.  To handle all possible NaN representations of SNaN and QNaN, since float16 uses short carrier type hence we need to promote them float values before invoking TestNG assertions. This conversion is accomplished by assertion wrappers
>  
> All the tasks are related and most of source/test are generated using scripts we should not go by the size of patch and review the templates files.

@jatin-bhateja I was wondering: what prompted the decision to add a new `BasicType` for `Float16`? Would each additional numeric type get a new `BasicType`? How many do we anticipate?

Currently, we are using `T_SHORT` for `Float16`, right?

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PR Comment: https://git.openjdk.org/jdk/pull/28002#issuecomment-3800362594