znver3 tuning part 1

[Jan Hubicka]

> On 3/31/21 1:08 PM, Jan Hubicka wrote:
> > > 
> > > 2021-03-15  Jan Hubicka  <hubicka@ucw.cz>
> > > 
> > > 	* config/i386/i386-options.c (processor_cost_table): Add znver3_cost.
> > > 	* config/i386/x86-tune-costs.h (znver3_cost): New gobal variable; copy
> > > 	of znver2_cost.
> > 
> > I have backported the patch to gcc10 branch as
> > g:aa99212489545c6c970a8f91b3d37ea6466cb988.
> > 
> > Honza
> > 
> 
> Looking at the backport, it has likely enabled PR99753.
> Please consider backporting 4f00c4d40a539360938607561460904663c64cda.

Not this patch but backport of the original Venkat's change indeed
triggers PR99763.  I am now testing backport if this revision.

Thanks,
Honza
> 
> Cheers,
> Martin