RFR(S): x86: 8190494: fix for different results with UseAVX=3 when calling AVX-512 native function via JNI.

[Vladimir Kozlov]

Thank you, Vivek

Changes looks good based on your description.

Please, explain why using mask register in scalar instructions is bad.

I will start pre-integration testing and let you know results.

Thanks,
Vladimir

On 11/30/17 7:28 AM, Deshpande, Vivek R wrote:
> Hi
> 
> I have bug fix for 8190494: Different results with UseAVX=3 when calling AVX-512 native function via JNI.
> 
> Mask register not being reset after JNI and the scalar floating point instructions using the mask register encoding with 
> AVX 512 in the assembler causing this problem.
> 
> I have tested it with jtreg on hotspot/compiler and SPECjvm2008 on knights landing and skylake.
> 
> Webrev:
> 
> http://cr.openjdk.java.net/~vdeshpande/8190494/webrev.00/
> 
> I have also updated the JBS entry.
> 
> https://bugs.openjdk.java.net/browse/JDK-8190494
> 
> Would you please review and sponsor it.
> 
> Regards,
> 
> Vivek
>