RFR: 8277997: Intrinsic creation for VectorMask.fromLong API

[Jatin Bhateja]

Summary of changes:

1) Inline expansion of VectorMask.fromLong API, this includes Java API implementation and C2 IR changes.
2) X86 backend support for AVX512 and AVX2 targets.
3) New IR transformation to handle following patterns:-
  a) Mask2Long + Long2Mask -> MaskCast (when source and destination mask lengths are equal)
  b) Long2Mask  + Mask2Long -> Long 
4) Following performance data is collected for new JMH micro included with the patch:-

System Configuration : Intel(R) Xeon(R) Platinum 8380 CPU @ 2.30GHz (40C 2S Icelake Server)

Benchmark | Baseline AVX2 (ops/ms) | Withopt AVX2 (ops/ms) | Gain factor | Baseline AVX3 (ops/ms) | Withopt AVX3(ops/ms) | Gain factor
-- | -- | -- | -- | -- | -- | --
MaskFromLongBenchmark.microMaskFromLong_Byte128 | 20050.884 | 36414.349 | 1.816096936 | 19699.631 | 36412.252 | 1.848372287
MaskFromLongBenchmark.microMaskFromLong_Byte256 | 17589.496 | 36418.368 | 2.070461143 | 17211.451 | 36407.44 | 2.115303352
MaskFromLongBenchmark.microMaskFromLong_Byte512 | 2824.411 | 2492.795 | 0.882589326 | 6359.071 | 36405.344 | 5.72494693
MaskFromLongBenchmark.microMaskFromLong_Byte64 | 23507.28 | 36424.668 | 1.549505855 | 22659.666 | 36420.345 | 1.607276338
MaskFromLongBenchmark.microMaskFromLong_Integer128 | 24567.895 | 36411.602 | 1.482080659 | 24620.619 | 36397.005 | 1.478313969
MaskFromLongBenchmark.microMaskFromLong_Integer256 | 23495.078 | 36411.981 | 1.549770595 | 22823.846 | 36395.703 | 1.594634971
MaskFromLongBenchmark.microMaskFromLong_Integer512 | 12377.022 | 11478.101 | 0.927371786 | 19701.118 | 36394.878 | 1.847350897
MaskFromLongBenchmark.microMaskFromLong_Integer64 | 22169.231 | 17791.849 | 0.802546962 | 23603.169 | 18055.166 | 0.76494669
MaskFromLongBenchmark.microMaskFromLong_Long128 | 22312.568 | 17859.474 | 0.800422166 | 22171.303 | 18106.295 | 0.816654529
MaskFromLongBenchmark.microMaskFromLong_Long256 | 24271.19 | 36416.883 | 1.500416049 | 24621.327 | 36390.41 | 1.478003602
MaskFromLongBenchmark.microMaskFromLong_Long512 | 15289.749 | 13860.775 | 0.906540389 | 23003.816 | 36396.033 | 1.582173714
MaskFromLongBenchmark.microMaskFromLong_Long64 | 27086.471 | 20490.828 | 0.756496777 | 27177.133 | 20441.112 | 0.752143797
MaskFromLongBenchmark.microMaskFromLong_Short128 | 23504.216 | 36412.66 | 1.549196961 | 22823.401 | 36417.799 | 1.595634191
MaskFromLongBenchmark.microMaskFromLong_Short256 | 20056.61 | 36403.277 | 1.815026418 | 19699.502 | 36412.605 | 1.84840231
MaskFromLongBenchmark.microMaskFromLong_Short512 | 4775.721 | 6827.594 | 1.429646749 | 17209.782 | 36388.226 | 2.114392036
MaskFromLongBenchmark.microMaskFromLong_Short64 | 24759.049 | 36381.539 | 1.469423927 | 24506.013 | 36413.099 | 1.48588426



Kindly review and share feedback.

Best Regards,
Jatin

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

Commit messages:
 - 8277997: Adding needed JVM arguments in micro.
 - 8277997: Intrinsic creation for VectorMask.fromLong API

Changes: https://git.openjdk.java.net/jdk/pull/6646/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6646&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8277997
  Stats: 516 lines in 77 files changed: 371 ins; 27 del; 118 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6646.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6646/head:pull/6646

PR: https://git.openjdk.java.net/jdk/pull/6646