RFR: 8302906: AArch64: Add SVE backend support for vector unsigned comparison

[Chang Peng]

This patch implements unsigned vector comparison on SVE.

1: Test:
All vector API test cases[1][2] passed without new failure. Existing test cases can cover all unsigned comparison conditions for all kinds of vector.

2: Performance:
(1): Benchmark:
As existing benchmarks in panama repo (such as [3]) have some issues [4] (We will fix them in a separate patch.), I collected performance data with a reduced jmh benchmark [5]. e.g. for ByteVector unsigned comparison:


@Benchmark
    public void byteVectorUnsignedCompare() {
        for (int j = 0; j < 200; j++) {
            for (int i = 0; i < bspecies.length(); i++) {
                ByteVector av = ByteVector.fromArray(bspecies, ba, i);
                ByteVector ca = ByteVector.fromArray(bspecies, bb, i);
                av.compare(VectorOperators.UNSIGNED_GT, ca).intoArray(br, i);
            }
        }
    }


(2): Performance data

Before:


Benchmark                               Score(op/ms)     Error
ByteVector.UNSIGNED_GT#size(1024)       4.846            3.419
ShortVector.UNSIGNED_GE#size(1024)      3.055            1.369
IntVector.UNSIGNED_LT#size(1024)        3.475            1.269
LongVector.UNSIGNED_LE#size(1024)       4.515            1.812


After:


Benchmark                               Score(op/ms)     Error
ByteVector.UNSIGNED_GT#size(1024)       493.937          1.389
ShortVector.UNSIGNED_GE#size(1024)      5308.796         20.557
IntVector.UNSIGNED_LT#size(1024)        4944.744         10.606
LongVector.UNSIGNED_LE#size(1024)       8459.605         28.683


[1] https://github.com/openjdk/jdk/tree/master/test/jdk/jdk/incubator/vector
[2] https://github.com/openjdk/jdk/tree/master/test/hotspot/jtreg/compiler/vectorapi
[3] https://github.com/openjdk/panama-vector/blob/2aade73adeabdf6a924136b17fd96ccc95c1d160/test/micro/org/openjdk/bench/jdk/incubator/vector/operation/ByteMaxVector.java#L1459
[4] https://bugs.openjdk.org/browse/JDK-8282850
[5] https://gist.github.com/changpeng1997/d311127e1015c107197f9b56a92b0fae

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

Commit messages:
 - 8302906: AArch64: Add SVE backend support for vector unsigned comparison

Changes: https://git.openjdk.org/jdk/pull/12725/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12725&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8302906
  Stats: 7 lines in 2 files changed: 4 ins; 1 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/12725.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12725/head:pull/12725

PR: https://git.openjdk.org/jdk/pull/12725