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

[Andrew Haley]

On Thu, 23 Feb 2023 07:05:43 GMT, Chang Peng <duke at openjdk.org> wrote:

> 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

src/hotspot/cpu/aarch64/c2_MacroAssembler_aarch64.cpp line 1123:

> 1121:     case BoolTest::uge: condition = Assembler::HS; break;
> 1122:     case BoolTest::ult: z1 = zm; z2 = zn; condition = Assembler::HI; break;
> 1123:     case BoolTest::ule: z1 = zm; z2 = zn; condition = Assembler::HS; break;

I'm sure you already know what to do here.

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

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