RFR: 8267190: Optimize Vector API test operations

[Sandhya Viswanathan]

On Wed, 19 May 2021 16:51:33 GMT, Paul Sandoz <psandoz at openjdk.org> wrote:

>> Vector API test operations (IS_DEFAULT, IS_FINITE, IS_INFINITE, IS_NAN and IS_NEGATIVE) are computed in three steps:
>> 1) reinterpreting the floating point vectors as integral vectors (int/long)
>> 2) perform the test in integer domain to get a int/long mask
>> 3) reinterpret the int/long mask as float/double mask
>> Step 3) currently is very slow. It can be optimized by modifying the Java code to utilize the existing reinterpret intrinsic.
>> 
>> For the VectorTestPerf attached to the JBS for JDK-8267190, the performance improves as follows:
>> 
>> Base:
>> Benchmark (size) Mode Cnt Score Error Units
>> VectorTestPerf.IS_DEFAULT 1024 thrpt 5 223.156 ± 90.452 ops/ms
>> VectorTestPerf.IS_FINITE 1024 thrpt 5 223.841 ± 91.685 ops/ms
>> VectorTestPerf.IS_INFINITE 1024 thrpt 5 224.561 ± 83.890 ops/ms
>> VectorTestPerf.IS_NAN 1024 thrpt 5 223.777 ± 70.629 ops/ms
>> VectorTestPerf.IS_NEGATIVE 1024 thrpt 5 218.392 ± 79.806 ops/ms
>> 
>> With patch:
>> Benchmark (size) Mode Cnt Score Error Units
>> VectorTestPerf.IS_DEFAULT 1024 thrpt 5 8812.357 ± 40.477 ops/ms
>> VectorTestPerf.IS_FINITE 1024 thrpt 5 7425.739 ± 296.622 ops/ms
>> VectorTestPerf.IS_INFINITE 1024 thrpt 5 8932.730 ± 269.988 ops/ms
>> VectorTestPerf.IS_NAN 1024 thrpt 5 8574.872 ± 498.649 ops/ms
>> VectorTestPerf.IS_NEGATIVE 1024 thrpt 5 8838.400 ± 11.849 ops/ms
>> 
>> Best Regards,
>> Sandhya
>
> Tier 1 to 3 tests pass on supported platforms

@PaulSandoz @vnkozlov Thanks a lot for the review. 
Paul, I have implemented your review comments. I also changed the switch to switch expression. Please take a look.

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PR: https://git.openjdk.java.net/jdk/pull/4039