RFR: 8358521: Optimize vector operations by reassociating broadcasted inputs [v4]

[Emanuel Peter]

On Tue, 24 Feb 2026 06:17:30 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Hi all,
>> 
>> This patch optimizes SIMD kernels making heavy use of broadcasted inputs through following reassociating ideal transformations.
>> 
>> 
>>  VectorOperation (VectorBroadcast INP1,  VectorBroadcast INP2) => 
>>                             VectorBroadcast (ScalarOpration INP1, INP2)
>> 
>>  VectorOperation (VectorBroadcast INP1) (VectorOperation (VectorBroadcast INP2) INP3) => 
>>                              VectorOperation INP3 (VectorOperation (VectorBroadcast INP1) (VectorOperation INP2))
>> 
>> 
>> The idea is to push broadcasts across the vector operation and replace the vector with an equivalent, cheaper scalar variant.  Currently, patch handles most common vector operations.
>> 
>> Following are the performance number of benchmark included with this patch on latest generation x86 targets:- 
>> 
>> **AMD Turin (2.1GHz)**
>> <img width="1122" height="355" alt="image" src="https://github.com/user-attachments/assets/3f5087bf-0e14-4c56-b0c2-3d23253bad54" />
>> 
>> **Intel Granite Rapids (2.1GHz)**
>> <img width="1105" height="325" alt="image" src="https://github.com/user-attachments/assets/c8481f86-4db2-4c4e-bd65-51542c59fe63" />
>> 
>> 
>> 
>> Kindly review and share your feedback.
>> 
>> Best Regards,
>> Jatin
>
> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Review comments resolutions

Just scanned the PR description:

 VectorOperation (VectorBroadcast INP1) (VectorOperation (VectorBroadcast INP2) INP3) => 
                             VectorOperation INP3 (VectorOperation (VectorBroadcast INP1) (VectorOperation INP2))

I think it should be `VectorBroadcast INP2` in both cases, and not `VectorOperation INP2`, because `INP2` is scalar, right?

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PR Comment: https://git.openjdk.org/jdk/pull/25617#issuecomment-3950091432