RFR: 8279508: Auto-vectorize Math.round API [v7]

[Sandhya Viswanathan]

On Wed, 23 Feb 2022 09:03:37 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)
>> 
>> 
>> TESTSIZE | Baseline AVX3 (ops/ms) | Withopt AVX3 (ops/ms) | Gain ratio | Baseline AVX2 (ops/ms) | Withopt AVX2 (ops/ms) | Gain ratio
>> -- | -- | -- | -- | -- | -- | --
>> 1024.00 | 510.41 | 1811.66 | 3.55 | 510.40 | 502.65 | 0.98
>> 2048.00 | 293.52 | 984.37 | 3.35 | 304.96 | 177.88 | 0.58
>> 1024.00 | 825.94 | 3387.64 | 4.10 | 750.77 | 1925.15 | 2.56
>> 2048.00 | 411.91 | 1942.87 | 4.72 | 412.22 | 1034.13 | 2.51
>> 
>> 
>> 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: Review comments resolved.

src/hotspot/cpu/x86/macroAssembler_x86.cpp line 8984:

> 8982: }
> 8983: 
> 8984: void MacroAssembler::round_double(Register dst, XMMRegister src, Register rtmp, Register rcx) {

Is it possible to implement this using the similar mxcsr change? In any case comments will help to review round_double and round_float code.

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