RFR: 8267663: AArch64: Add unsigned comparison operators on AArch64

[Andrew Haley]

On Fri, 4 Jun 2021 11:35:16 GMT, Eric Liu <eliu at openjdk.org> wrote:

> 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

src/hotspot/cpu/aarch64/aarch64_neon_ad.m4 line 889:

> 887: 
> 888: static void neon_compare(C2_MacroAssembler masm, FloatRegister dst, BasicType bt,
> 889:                          FloatRegister src1, FloatRegister src2, int cond, bool isX) {

Passing masm by value, rather than reference, is unconventional. There's no reason to do that.

src/hotspot/cpu/aarch64/aarch64_neon_ad.m4 line 930:

> 928: }
> 929: %}
> 930: 

This stuff should be in C2_MacroAssembler.

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

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