8244926: Add absolute check for int/long to generate Abs nodes

[Tobias Hartmann]

Hi Yang,

looks good to me too.

Best regards,
Tobias

On 12.06.20 07:28, Yang Zhang wrote:
> Hi Nils
> Thanks  a lot for your review.
> 
> Hi reviewers
> Any other comments?
> 
> Regards,
> Yang
> 
> -----Original Message-----
> From: hotspot-compiler-dev <hotspot-compiler-dev-bounces at openjdk.java.net> On Behalf Of Nils Eliasson
> Sent: Thursday, June 11, 2020 5:21 PM
> To: hotspot-compiler-dev at openjdk.java.net
> Subject: Re: 8244926: Add absolute check for int/long to generate Abs nodes
> 
> Hi Yang,
> 
> The patch looks good.
> 
> Reviewed.
> 
> Best regards,
> Nils Eliasson
> 
> 
> On 2020-06-11 07:36, Yang Zhang wrote:
>> Hi,
>>
>> Ping it again. Could anyone help to review this patch?
>>
>> Regards
>> Yang
>>
>> -----Original Message-----
>> From: hotspot-compiler-dev 
>> <hotspot-compiler-dev-bounces at openjdk.java.net> On Behalf Of Yang 
>> Zhang
>> Sent: Thursday, June 4, 2020 4:28 PM
>> To: hotspot-compiler-dev at openjdk.java.net
>> Cc: nd <nd at arm.com>
>> Subject: RFR: 8244926: Add absolute check for int/long to generate Abs 
>> nodes
>>
>> Hi,
>>
>> May I have a review of this enhancement of absolute check for int/long?
>>
>> JBS: https://bugs.openjdk.java.net/browse/JDK-8244926
>> Webrev: http://cr.openjdk.java.net/~yzhang/8244926/webrev.00/
>>   
>> There is absolute value check for float/double already [1]. In this patch, absolute value check for integer/long is added. The following patterns can be matched to AbsI/L nodes:
>> ((a < 0) ? -a : a)
>> ((a <= 0) ? -a : a)
>> ((a > 0) ? a : -a)
>> ((a >= 0) ? a : -a)
>>
>> Test case:
>> public static int absi(int a) {
>>      return ((a < 0) ? -a : a);
>> }
>>
>> With c2, AbsI node is generated and matched. The following snippet is generated on x86:
>>    0x00007f67c8b6155b:   mov    %ecx,%r11d
>>    0x00007f67c8b6155e:   sar    $0x1f,%r11d
>>    0x00007f67c8b61562:   mov    %ecx,%r10d
>>    0x00007f67c8b61565:   xor    %r11d,%r10d
>>    0x00007f67c8b61568:   sub    %r11d,%r10d
>>
>> On AArch64:
>>    0x0000ffffa8b878e4:   cmp	w3, wzr
>>    0x0000ffffa8b878e8:   cneg	w17, w3, lt  // lt = tstop
>>
>> Note: AArch64 result is based on this patch which is in review [2].
>>
>> Test:
>> Full jtreg on x86 and AArch64, no new failure
>>
>> Performance:
>> Jmh test is uploaded.
>> http://cr.openjdk.java.net/~yzhang/8244926/TestScalar.java
>>
>> X86
>> Before:
>> Benchmark             (size)  Mode  Cnt     Score   Error  Units
>> TestScalar.testAbsI1    1024  avgt   25  2648.235 ± 0.810  us/op
>> TestScalar.testAbsI2    1024  avgt   25  2647.702 ± 0.431  us/op
>> TestScalar.testAbsI3    1024  avgt   25  2647.605 ± 0.346  us/op
>> TestScalar.testAbsI4    1024  avgt   25  2647.574 ± 0.651  us/op
>> TestScalar.testAbsL1    1024  avgt   25  3165.787 ± 0.976  us/op
>> TestScalar.testAbsL2    1024  avgt   25  3166.582 ± 2.217  us/op
>> TestScalar.testAbsL3    1024  avgt   25  3168.097 ± 4.071  us/op
>> TestScalar.testAbsL4    1024  avgt   25  3167.222 ± 2.573  us/op
>>
>> After:
>> Benchmark             (size)  Mode  Cnt     Score   Error  Units
>> TestScalar.testAbsI1    1024  avgt   25  2264.637 ± 1.164  us/op
>> TestScalar.testAbsI2    1024  avgt   25  2264.318 ± 0.427  us/op
>> TestScalar.testAbsI3    1024  avgt   25  2264.998 ± 0.903  us/op
>> TestScalar.testAbsI4    1024  avgt   25  2264.602 ± 0.625  us/op
>> TestScalar.testAbsL1    1024  avgt   25  2376.513 ± 0.345  us/op
>> TestScalar.testAbsL2    1024  avgt   25  2376.681 ± 0.565  us/op
>> TestScalar.testAbsL3    1024  avgt   25  2377.012 ± 0.643  us/op
>> TestScalar.testAbsL4    1024  avgt   25  2376.921 ± 0.699  us/op
>>
>> AArch64:
>> Before:
>> Benchmark             (size)  Mode  Cnt     Score   Error  Units
>> TestScalar.testAbsI1    1024  avgt   25  1858.831 ± 1.249  us/op
>> TestScalar.testAbsI2    1024  avgt   25  1860.248 ± 1.365  us/op
>> TestScalar.testAbsI3    1024  avgt   25  1859.571 ± 1.177  us/op
>> TestScalar.testAbsI4    1024  avgt   25  1859.970 ± 0.882  us/op
>> TestScalar.testAbsL1    1024  avgt   25  1871.520 ± 2.592  us/op
>> TestScalar.testAbsL2    1024  avgt   25  1872.728 ± 2.301  us/op
>> TestScalar.testAbsL3    1024  avgt   25  1872.852 ± 2.455  us/op
>> TestScalar.testAbsL4    1024  avgt   25  1872.720 ± 2.652  us/op
>>
>> After:
>> Benchmark             (size)  Mode  Cnt     Score   Error  Units
>> TestScalar.testAbsI1    1024  avgt   25  1422.781 ± 1.788  us/op
>> TestScalar.testAbsI2    1024  avgt   25  1423.778 ± 2.612  us/op
>> TestScalar.testAbsI3    1024  avgt   25  1424.327 ± 2.065  us/op
>> TestScalar.testAbsI4    1024  avgt   25  1423.269 ± 1.437  us/op
>> TestScalar.testAbsL1    1024  avgt   25  1434.279 ± 2.312  us/op
>> TestScalar.testAbsL2    1024  avgt   25  1433.900 ± 2.341  us/op
>> TestScalar.testAbsL3    1024  avgt   25  1435.967 ± 2.270  us/op
>> TestScalar.testAbsL4    1024  avgt   25  1437.495 ± 0.957  us/op
>>
>> [1] 
>> http://hg.openjdk.java.net/jdk/jdk/file/dd652a1b2a39/src/hotspot/share
>> /opto/cfgnode.cpp#l1519 [2] 
>> https://mail.openjdk.java.net/pipermail/aarch64-port-dev/2020-May/0088
>> 61.html
>>
>>
>> Regards,
>> Yang
>>
>