RFR: 8279508: Auto-vectorize Math.round API [v17]

[Tobias Hartmann]

On Sun, 13 Mar 2022 06:36:15 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Summary of changes:
>> - Intrinsify Math.round(float) and Math.round(double) APIs.
>> - Extend auto-vectorizer to infer vector operations on encountering scalar IR nodes for above intrinsics.
>> - Test creation using new IR testing framework.
>> 
>> Following are the performance number of a JMH micro included with the patch 
>> 
>> Test System: Intel(R) Xeon(R) Platinum 8380 CPU @ 2.30GHz (Icelake Server)
>> 
>> 
>> Benchmark | TESTSIZE | Baseline AVX3 (ops/ms) | Withopt AVX3 (ops/ms) | Gain ratio | Baseline AVX2 (ops/ms) | Withopt AVX2 (ops/ms) | Gain ratio
>> -- | -- | -- | -- | -- | -- | -- | --
>> FpRoundingBenchmark.test_round_double | 1024.00 | 504.15 | 2209.54 | 4.38 | 510.36 | 548.39 | 1.07
>> FpRoundingBenchmark.test_round_double | 2048.00 | 293.64 | 1271.98 | 4.33 | 293.48 | 274.01 | 0.93
>> FpRoundingBenchmark.test_round_float | 1024.00 | 825.99 | 4754.66 | 5.76 | 751.83 | 2274.13 | 3.02
>> FpRoundingBenchmark.test_round_float | 2048.00 | 412.22 | 2490.09 | 6.04 | 388.52 | 1334.18 | 3.43
>> 
>> 
>> Kindly review and share your feedback.
>> 
>> Best Regards,
>> Jatin
>
> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8279508: Windows build failure fix.

`compiler/c2/cr6340864/TestFloatVect.java` and `TestDoubleVect.java` fail on Windows:


# A fatal error has been detected by the Java Runtime Environment:
#
#  EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x000001971b940123, pid=56524, tid=57368
#
# JRE version: Java(TM) SE Runtime Environment (19.0) (fastdebug build 19-internal-2022-03-14-0834080.tobias.hartmann.jdk2)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 19-internal-2022-03-14-0834080.tobias.hartmann.jdk2, mixed mode, sharing, tiered, compressed oops, compressed class ptrs, g1 gc, windows-amd64)
# Problematic frame:
# J 205 c2 compiler.c2.cr6340864.TestFloatVect.test_round([I[F)V (24 bytes) @ 0x000001971b940123 [0x000001971b93ffe0+0x0000000000000143]

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PR: https://git.openjdk.java.net/jdk/pull/7094