RFR: 8342393: Promote commutative vector IR node sharing [v12]

[Emanuel Peter]

On Wed, 22 Jan 2025 10:55:57 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Patch promotes the sharing of commutative vector IR with the same inputs but different input ordering.
>> Unlike scalar IR where we perform edge swapping by [sorting inputs](https://github.com/openjdk/jdk/blob/master/src/hotspot/share/opto/addnode.cpp#L122) based on node indices during IR idealization, for vector IR we chose a simpler approach to decorate commutative operations with a special node-level flag during IR construction thus
>> obviating any dependency on explicit idealization routines. This flag is later used during GVN hashing to enable node sharing.  
>> 
>> Following are the performance stats for JMH micro included with the patch.
>> 
>> 
>> Granite Rapids (P-core Xeon Server)
>> Baseline : 
>> Benchmark                                                                (size)   Mode  Cnt      Score   Error   Units
>> VectorCommutativeOperSharingBenchmark.commutativeByteOperationShairing     1024  thrpt    2   8982.549          ops/ms
>> VectorCommutativeOperSharingBenchmark.commutativeIntOperationShairing      1024  thrpt    2   6072.773          ops/ms
>> VectorCommutativeOperSharingBenchmark.commutativeLongOperationShairing     1024  thrpt    2   2368.856          ops/ms
>> VectorCommutativeOperSharingBenchmark.commutativeShortOperationShairing    1024  thrpt    2  15215.087          ops/ms
>> 
>> Withopt:
>> Benchmark                                                                (size)   Mode  Cnt      Score   Error   Units
>> VectorCommutativeOperSharingBenchmark.commutativeByteOperationShairing     1024  thrpt    2  11963.554          ops/ms
>> VectorCommutativeOperSharingBenchmark.commutativeIntOperationShairing      1024  thrpt    2   7036.088          ops/ms
>> VectorCommutativeOperSharingBenchmark.commutativeLongOperationShairing     1024  thrpt    2   2906.731          ops/ms
>> VectorCommutativeOperSharingBenchmark.commutativeShortOperationShairing    1024  thrpt    2  17148.131          ops/ms
>> 
>> Sierra Forest (E-core Xeon Server)
>> Baseline:
>> Benchmark                                                                (size)   Mode  Cnt     Score   Error   Units
>> VectorCommutativeOperSharingBenchmark.commutativeByteOperationShairing     1024  thrpt    2  2444.359          ops/ms
>> VectorCommutativeOperSharingBenchmark.commutativeIntOperationShairing      1024  thrpt    2  1710.256          ops/ms
>> VectorCommutativeOperSharingBenchmark.commutativeLongOperationShairing     1024  thrpt    2   308.766          ops/ms
>> VectorCommutativeOperSharingBenc...
>
> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Review suggestions incorporated.

@jatin-bhateja The patch looks good now. I'll run testing again just to be sure. Feel free to ping me again in 1-2 days!

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PR Review: https://git.openjdk.org/jdk/pull/22863#pullrequestreview-2567015428