RFR: 8358521: Optimize vector operations by reassociating broadcasted inputs [v3]

[Xiaohong Gong]

On Tue, 10 Feb 2026 05:33:28 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> src/hotspot/share/opto/vectornode.cpp line 1317:
>> 
>>> 1315:   }
>>> 1316:   return nullptr;
>>> 1317: }
>> 
>> Reassociation can be a separate optimization for vector nodes to me. Do you think it's better to split it as a separate change following the broadcast optimization? We can add specific tests for it.
>
> Reassociation are only applicable to integral vector operation, for vector API we only use fp-fast model semantics for reductions of floating point vector, I have now added tests to cover all possible transformations so that we can include both associated transforms in same patch.

I still keep my point that separating the reassociation as a separate PR for better maintain. WDYT?

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PR Review Comment: https://git.openjdk.org/jdk/pull/25617#discussion_r2839345895