RFR: 8290322: Optimize Vector.rearrange over byte vectors for AVX512BW targets. [v5]

[Jatin Bhateja]

> Hi All,
> 
> Currently re-arrange over 512bit bytevector is optimized for targets supporting AVX512_VBMI feature, this patch generates efficient JIT sequence to handle it for AVX512BW targets.  Following performance results with newly added benchmark shows
> significant speedup.
> 
> System:  Intel(R) Xeon(R) Platinum 8280 CPU @ 2.70GHz (CascadeLake 28C 2S)
> 
> 
> Baseline:
> =========
> Benchmark                                     (size)   Mode  Cnt      Score   Error   Units
> RearrangeBytesBenchmark.testRearrangeBytes16     512  thrpt    2  16350.330          ops/ms
> RearrangeBytesBenchmark.testRearrangeBytes32     512  thrpt    2  15991.346          ops/ms
> RearrangeBytesBenchmark.testRearrangeBytes64     512  thrpt    2     34.423          ops/ms
> RearrangeBytesBenchmark.testRearrangeBytes8      512  thrpt    2  10873.348          ops/ms
> 
> 
> With-opt:
> =========
> Benchmark                                     (size)   Mode  Cnt      Score   Error   Units
> RearrangeBytesBenchmark.testRearrangeBytes16     512  thrpt    2  16062.624          ops/ms
> RearrangeBytesBenchmark.testRearrangeBytes32     512  thrpt    2  16028.494          ops/ms
> RearrangeBytesBenchmark.testRearrangeBytes64     512  thrpt    2   8741.901          ops/ms
> RearrangeBytesBenchmark.testRearrangeBytes8      512  thrpt    2  10983.226          ops/ms
> 
> 
> Kindly review and share your feedback.
> 
> Best Regards,
> Jatin

Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:

  8290322: Further optimization based on review comments.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/9498/files
  - new: https://git.openjdk.org/jdk/pull/9498/files/c7f7dd13..664926fb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9498&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9498&range=03-04

  Stats: 22 lines in 3 files changed: 0 ins; 4 del; 18 mod
  Patch: https://git.openjdk.org/jdk/pull/9498.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9498/head:pull/9498

PR: https://git.openjdk.org/jdk/pull/9498