CR for RFR 8170039

[Vladimir Kozlov]

Hi Michael,

Please, use FLAG_IS_DEFAULT(UseAVX) to check if flag is not changed on 
command line.

Also I think is better to set a local boolean at the beginning of 
generate_get_cpu_info() method instead of using saved_useavx.

And modify code at lines 595-608 to set default values based on cpu 
FLAG_IS_DEFAULT(UseAVX, use_avx) and using an other local. Guard it with 
if (FLAG_IS_DEFAULT(UseAVX)) and issue warning if flag set on command 
line bud conflict with supported by CPU value (as we do for other flags).

Thanks,
Vladimir

On 11/21/16 10:59 AM, Berg, Michael C wrote:
> Hi Folks,
>
> Glibc uses a single convention for save/restore, so when the user asks
> for UseAVX={0,1,2} that excludes EVEX (3), we should offer non EVEX
> based save/restore for that path by not emitting the EVEX vector check code.
>
>
>
> This code was tested as follows: hotspot jreg, SPECjvm2008, SPECjvm98 on
> hsw, skx and knl targets complete with no issues on 64-bit.
>
>
> Bug-id: https://bugs.openjdk.java.net/browse/JDK-8170039
>
>
> webrev: http://cr.openjdk.java.net/~mcberg/8170039/webrev.01
>
>
>
> Regards,
>
> Michael
>