[vectorIntrinsics+mask] RFR: 8273949: Intrinsic creation for VectorMask.toLong operation. [v2]

[Paul Sandoz]

On Mon, 20 Sep 2021 04:19:02 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Summary of changes:
>> - Intrinsification of VectorMask.toLong() API.
>> - Supports inline expansion for both AVX512 and non-AVX512 targets.
>> - Used toLong() API to optimize existing Java API implementation of VectorMask.laneIsSet() operation.
>> 
>> Following performance number are generated using JMH benchmark modification included with the patch.
>> 
>> System:  Intel(R) Xeon(R) Platinum 8280 CPU @ 2.70GHz (Cascade Lake Server 28C 2S)
>> 
>> Benchmark | VECSIZE | Baseline Score (ops/ms) | With Opt (ops/ms) | Gain Ratio
>> -- | -- | -- | -- | --
>> MaskQueryOperationsBenchmark.testToLongByte | 128 | 90451.424 | 346941.379 | 3.835665196
>> MaskQueryOperationsBenchmark.testToLongByte | 256 | 63127.764 | 338331.425 | 5.359471072
>> MaskQueryOperationsBenchmark.testToLongByte | 512 | 40543.264 | 313836.333 | 7.740776199
>> MaskQueryOperationsBenchmark.testToLongLong | 128 | 171989.714 | 152872.758 | 0.88884826
>> MaskQueryOperationsBenchmark.testToLongLong | 256 | 164702.273 | 324794.578 | 1.972010295
>> MaskQueryOperationsBenchmark.testToLongLong | 512 | 122667.916 | 318060.096 | 2.59285481
>> MaskQueryOperationsBenchmark.testToLongShort | 128 | 122656.408 | 346691.082 | 2.826522378
>> MaskQueryOperationsBenchmark.testToLongShort | 256 | 96838.555 | 360909.28 | 3.726917239
>> MaskQueryOperationsBenchmark.testToLongShort | 512 | 63119.009 | 313075.159 | 4.960077225
>> MaskQueryOperationsBenchmark.testToLonglong | 128 | 180855.623 | 324620.433 | 1.794914792
>> MaskQueryOperationsBenchmark.testToLonglong | 256 | 122705.631 | 324315.916 | 2.643040204
>> MaskQueryOperationsBenchmark.testToLonglong | 512 | 90396.687 | 324318.095 | 3.58772103
>
> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8273949: Review comments resolution

src/jdk.incubator.vector/share/classes/jdk/incubator/vector/AbstractMask.java line 68:

> 66:         if (i < 0 || i >= length()) {
> 67:             throw new IllegalArgumentException("Index " + i + " must be zero or positive, and less than " + length());
> 68:         }

Apologies i should have previously said use `Objects.checkIndex(i, length())`. In fact lets call `length` once:

    int length = length();
    Objects.checkIndex(i, length);
    if (length <= Long.SIZE) {
    ...


Separately i wonder if the second bounds check should be `if i <= Long.SIZE`, since the first bounds check should dominate in many cases?

(I know there are other areas where we should `Objects.checkIndex` e.g. `*MaxVector.lane/withLane` but we can fix those later.)

-------------

PR: https://git.openjdk.java.net/panama-vector/pull/126