Hi, here is followup patch to add skylake-avx512.
gcc/
	* config/i386/driver-i386.c (host_detect_local_cpu): Detect skylake-avx512.

> -----Original Message-----
> From: Uros Bizjak [mailto:ubizjak@gmail.com]
> Sent: Sunday, November 12, 2017 5:05 PM
> To: Koval, Julia <julia.koval@intel.com>
> Cc: GCC Patches <gcc-patches@gcc.gnu.org>; Kirill Yukhin
> <kirill.yukhin@gmail.com>
> Subject: Re: [x86][patch] Add -march=cannonlake.
> 
> On Sat, Nov 11, 2017 at 10:10 PM, Koval, Julia <julia.koval@intel.com> wrote:
> > Hi Uros,
> > I fixed comments.
> > Btw, I haven't found skylake-avx512 in driver-i386.c at all. Is it intended or
> should I add it?
> 
> It looks like an oversight to me. If there are no "skylake-avx512"
> model, then the driver goes through "This is unknown ..." for
> -march=native and hopefully chooses the next most appropriate choice.
> Please add "skylake-avx512" in a follow-up patch.
> 
> > Thanks,
> > Julia
> >
> > gcc/
> >         * config.gcc: Add -march=cannonlake.
> >         * config/i386/driver-i386.c (host_detect_local_cpu): Detect cannonlake.
> >         * config/i386/i386-c.c (ix86_target_macros_internal): Handle cannonlake.
> >         * config/i386/i386.c (processor_costs): Add m_CANNONLAKE.
> >         (PTA_CANNONLAKE): New.
> >         (processor_target_table): Add cannonlake.
> >         (ix86_option_override_internal): Ditto.
> >         (fold_builtin_cpu): Ditto.
> >         (get_builtin_code_for_version): Handle cannonlake.
> >         (M_INTEL_COREI7_CANNONLAKE): New.
> >         * config/i386/i386.h (TARGET_CANNONLAKE,
> PROCESSOR_CANNONLAKE): New.
> >         * doc/invoke.texi: Add -march=cannonlake.
> > gcc/testsuite/
> >         * gcc.target/i386/funcspec-56.inc: Handle new march.
> >         * g++.dg/ext/mv16.C: Ditto.
> > libgcc/
> >         * config/i386/cpuinfo.c (get_intel_cpu): Handle cannonlake.
> >         * config/i386/cpuinfo.h (processor_subtypes): Add
> INTEL_COREI7_CANNONLAKE.
> 
> OK.
> 
> Thanks,
> Uros.