RFR: 8267663: [vector] Add unsigned comparison operators on AArch64 [v2]

[Eric Liu]

> This patch implements unsigned vector comparison on AArch64. The
> performance of unsigned comparison improves about 4x~5x in my local with
> Byte128Vector.java[1].
> 
> Before:
> Benchmark                               Score(op/ms)     Error
> Byte128Vector.UNSIGNED_GE#size(1024)    99.953           6.17
> Byte128Vector.UNSIGNED_GT#size(1024)    95.334           8.865
> Byte128Vector.UNSIGNED_LE#size(1024)    76.908           24.332
> Byte128Vector.UNSIGNED_LT#size(1024)    78.362           23.507
> 
> After:
> Benchmark                               Score(op/ms)     Error
> Byte128Vector.UNSIGNED_GE#size(1024)    421.809          25.57
> Byte128Vector.UNSIGNED_GT#size(1024)    420.653          26.779
> Byte128Vector.UNSIGNED_LE#size(1024)    316.754          92.889
> Byte128Vector.UNSIGNED_LT#size(1024)    423.683          26.508
> 
> [Test]
> - All vector API test cases passed without new failure. 8265312[2] has
>   been implemented this on x86 and supplied sufficient test cases for
>   all kinds of vector.
> - No performance regression for other comparisons.
> - libjvm.so drops off about 200KB after this patch by combining those
>   vector compare rules.
> 
> [1] https://github.com/openjdk/panama-vector/blob/vectorIntrinsics/test/jdk/jdk/incubator/vector/benchmark/src/main/java/benchmark/jdk/incubator/vector/Byte128Vector.java#L1198
> [2] https://github.com/openjdk/panama-vector/pull/68

Eric Liu has updated the pull request incrementally with one additional commit since the last revision:

  Refactor code
  
  - public elemBytes_to_Arrangement and make it more generalized since it
    maybe useful in the future.
  - move neon_compare into macroAssembler.
  
  Change-Id: I7596de03abb066574cf430d935edd07cd627e14b

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4358/files
  - new: https://git.openjdk.java.net/jdk/pull/4358/files/58ab4eed..23e0c7c4

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4358&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4358&range=00-01

  Stats: 199 lines in 4 files changed: 65 ins; 126 del; 8 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4358.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4358/head:pull/4358

PR: https://git.openjdk.java.net/jdk/pull/4358