RFR: 8309130: x86_64 AVX512 intrinsics for Arrays.sort methods (int, long, float and double arrays) [v7]

[Srinivas Vamsi Parasa]

> The goal is to develop faster sort routines for x86_64 CPUs by taking advantage of AVX512 instructions. This enhancement provides an order of magnitude speedup for Arrays.sort() using int, long, float and double arrays.
> 
> This PR shows upto ~13x improvement for 32-bit datatypes (int, float) and upto 8x improvement for 64-bit datatypes (long, double) as shown in the performance data below.
> 
> **Arrays.sort performance data using JMH benchmarks** 
> 
> |	Arrays.sort benchmark	|	Array Size	|	Baseline (us/op)	|	AVX512 Sort (us/op)	|	Speedup	|
> |	---	|	---	|	---	|	---	|	---	|
> |	ArraysSort.doubleSort	|	100	|	0.639	|	0.217	|	2.9x	|
> |	ArraysSort.doubleSort	|	1000	|	8.707	|	3.421	|	2.5x	|
> |	ArraysSort.doubleSort	|	10000	|	349.267	|	43.56	|	**8.0x**	|
> |	ArraysSort.doubleSort	|	100000	|	4721.17	|	579.819	|	**8.1x**	|
> |	ArraysSort.floatSort	|	100	|	0.722	|	0.129	|	5.6x	|
> |	ArraysSort.floatSort	|	1000	|	9.1	|	2.356	|	3.9x	|
> |	ArraysSort.floatSort	|	10000	|	336.472	|	26.706	|	**12.6x**	|
> |	ArraysSort.floatSort	|	100000	|	4804.716	|	427.397	|	**11.2x**	|
> |	ArraysSort.intSort	|	100	|	0.61	|	0.111	|	5.5x	|
> |	ArraysSort.intSort	|	1000	|	8.534	|	2.025	|	4.2x	|
> |	ArraysSort.intSort	|	10000	|	310.97	|	24.082	|	**12.9x**	|
> |	ArraysSort.intSort	|	100000	|	4484.94	|	381.01	|	**11.8x**	|
> |	ArraysSort.longSort	|	100	|	0.636	|	0.28	|	2.3x	|
> |	ArraysSort.longSort	|	1000	|	8.646	|	4.425	|	2.0x	|
> |	ArraysSort.longSort	|	10000	|	322.116	|	53.094	|	**6.1x**	|
> |	ArraysSort.longSort	|	100000	|	4448.171	|	696.773	|	**6.4x**	|

Srinivas Vamsi Parasa has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains seven additional commits since the last revision:

 - Merge branch 'openjdk:master' into avx512sort
 - fix license in one file
 - Update test/micro/org/openjdk/bench/java/util/ArraysSort.java
   
   Co-authored-by: Andrew Haley <aph-open at littlepinkcloud.com>
 - fix license
 - Merge branch 'master' of https://git.openjdk.java.net/jdk into avx512sort
 - remove libstdc++
 - 8309130: x86_64 AVX512 intrinsics for Arrays.sort methods (int, long, float and double arrays)

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/14227/files
  - new: https://git.openjdk.org/jdk/pull/14227/files/1dc9589e..3bd12ec5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14227&range=06
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14227&range=05-06

  Stats: 57637 lines in 809 files changed: 47983 ins; 6934 del; 2720 mod
  Patch: https://git.openjdk.org/jdk/pull/14227.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14227/head:pull/14227

PR: https://git.openjdk.org/jdk/pull/14227