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

[Chang Peng]

On Thu, 23 Feb 2023 11:05:11 GMT, Andrew Haley <aph 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.

Ok, thanks. I will remove these switch-case statements.

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

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