[PATCH] x86: Tune Skylake, Cannonlake and Icelake as Haswell

[H.J. Lu]

On Fri, Jul 13, 2018 at 9:07 AM, Jan Hubicka <hubicka@ucw.cz> wrote:
>> > > > diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
>> > > > index 9e46b7b136f..762ab89fc9e 100644
>> > > > --- a/gcc/config/i386/i386.c
>> > > > +++ b/gcc/config/i386/i386.c
>> > > > @@ -137,17 +137,22 @@ const struct processor_costs *ix86_cost = NULL;
>> > > >  #define m_CORE2 (HOST_WIDE_INT_1U<<PROCESSOR_CORE2)
>> > > >  #define m_NEHALEM (HOST_WIDE_INT_1U<<PROCESSOR_NEHALEM)
>> > > >  #define m_SANDYBRIDGE (HOST_WIDE_INT_1U<<PROCESSOR_SANDYBRIDGE)
>> > > > -#define m_HASWELL (HOST_WIDE_INT_1U<<PROCESSOR_HASWELL)
>> > > > +#define m_HASWELL ((HOST_WIDE_INT_1U<<PROCESSOR_HASWELL) \
>> > > > +                  | (HOST_WIDE_INT_1U<<PROCESSOR_SKYLAKE) \
>> > > > +                  | (HOST_WIDE_INT_1U<<PROCESSOR_SKYLAKE_AVX512) \
>> > > > +                  | (HOST_WIDE_INT_1U<<PROCESSOR_CANNONLAKE) \
>> > > > +                  | (HOST_WIDE_INT_1U<<PROCESSOR_ICELAKE_CLIENT) \
>> > > > +                  | (HOST_WIDE_INT_1U<<PROCESSOR_ICELAKE_SERVER))
>> > > >
>> > >
>> > > Please introduce a new per-family define and group processors in this
>> > > define. Something like m_BDVER, m_BTVER and m_AMD_MULTIPLE for AMD
>> > targets.
>> > > We should not redefine m_HASWELL to include unrelated families.
>> > >
>> >
>> > Here is the updated patch.  OK for trunk if all tests pass?
>> >
>> >
>> OK.
>
> We have also noticed that benchmarks on skylake are not good compared to
> haswell, this nicely explains it.  I think this is -march=native regression
> compared to GCC versions that did not suppored better CPUs than Haswell.  So it
> would be nice to backport it.

Yes, we should.   Here is the patch to backport to GCC 8.  OK for GCC 8 after
it has been checked into trunk?

Thanks.

-- 
H.J.
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