RFR: 8289186: Support predicated vector load/store operations over X86 AVX2 targets. [v5]

[Vladimir Kozlov]

On Fri, 8 Jul 2022 08:38:36 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Hi All,
>> 
>> [JDK-8283667](https://bugs.openjdk.org/browse/JDK-8283667) added the support to handle masked loads on non-predicated targets by blending the loaded contents with zero vector iff unmasked portion of load does not span beyond array bounds.
>> 
>> X86 AVX2 offers direct predicated vector loads/store instruction for non-sub word type.
>> 
>> This patch adds the efficient backend implementation for predicated memory operations over int/long/float/double vectors.
>> 
>> Please find below the JMH micro stats with and without patch.
>> 
>> 
>> 
>> System : Intel(R) Xeon(R) Platinum 8280 CPU @ 2.70GHz [28C 2S Cascadelake Server]
>> 
>> Baseline:
>> Benchmark                                          (inSize)  (outSize)   Mode  Cnt    Score   Error   Units
>> LoadMaskedIOOBEBenchmark.byteLoadArrayMaskIOOBE        1026       1152  thrpt    2  712.218          ops/ms
>> LoadMaskedIOOBEBenchmark.doubleLoadArrayMaskIOOBE      1026       1152  thrpt    2  156.912          ops/ms
>> LoadMaskedIOOBEBenchmark.floatLoadArrayMaskIOOBE       1026       1152  thrpt    2  255.814          ops/ms
>> LoadMaskedIOOBEBenchmark.intLoadArrayMaskIOOBE         1026       1152  thrpt    2  267.688          ops/ms
>> LoadMaskedIOOBEBenchmark.longLoadArrayMaskIOOBE        1026       1152  thrpt    2  140.957          ops/ms
>> LoadMaskedIOOBEBenchmark.shortLoadArrayMaskIOOBE       1026       1152  thrpt    2  474.009          ops/ms
>> 
>> 
>> With Opt:
>> Benchmark                                          (inSize)  (outSize)   Mode  Cnt     Score   Error   Units
>> LoadMaskedIOOBEBenchmark.byteLoadArrayMaskIOOBE        1026       1152  thrpt    2   742.781          ops/ms
>> LoadMaskedIOOBEBenchmark.doubleLoadArrayMaskIOOBE      1026       1152  thrpt    2  1241.021          ops/ms
>> LoadMaskedIOOBEBenchmark.floatLoadArrayMaskIOOBE       1026       1152  thrpt    2  2333.311          ops/ms
>> LoadMaskedIOOBEBenchmark.intLoadArrayMaskIOOBE         1026       1152  thrpt    2  3258.754          ops/ms
>> LoadMaskedIOOBEBenchmark.longLoadArrayMaskIOOBE        1026       1152  thrpt    2  1757.192          ops/ms
>> LoadMaskedIOOBEBenchmark.shortLoadArrayMaskIOOBE       1026       1152  thrpt    2   472.590          ops/ms
>> 
>> 
>> Predicated memory operation over sub-word type will be handled in a subsequent patch. 
>> 
>> Kindly review and share your feedback.
>> 
>> Best Regards,
>> Jatin
>
> Jatin Bhateja has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains five commits:
> 
>  - Merge branch 'master' of http://github.com/openjdk/jdk into JDK-8289186
>  - 8289186: jcheck failure
>  - 8289186: Review comments resolved.
>  - 8289186: Review comments resolved.
>  - 8289186: Support predicated vector load/store operations over X86 AVX2 targets.

I started testing.

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PR: https://git.openjdk.org/jdk/pull/9324