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Re: [PATCH] x86: Add -march=cascadelake


On Wed, Dec 12, 2018 at 10:48 AM Wei Xiao <wei.william.xiao@gmail.com> wrote:
>
> Hi Uros and other reviewers,
>
> I'd like to split the work into 2 parts:
> 1) Basic processor enabling.
> 2) Processor type dynamic check.
>
> Let's use a separate patch to implement the part 2.
> The part 1 is implemented by attached patch.
> Is it ok for trunk?
>
> Wei
>
> gcc/
>       * common/config/i386/i386-common.c (processor_names): Add cascadelake.
>       (processor_alias_table): Add cascadelake.
>       * config.gcc: Add -march=cascadelake.
>       * config/i386/i386-c.c (ix86_target_macros_internal): Handle cascadelake.
>       * config/i386/i386.c (Add m_CASCADELAKE): New.
>       (processor_cost_table): Add cascadelake.
>       (get_builtin_code_for_version): Handle cascadelake.
>       * config/i386/i386.h (TARGET_CASCADELAKE, PROCESSOR_CASCADELAKE): New.
>       (PTA_CASCADELAKE): Ditto.
>       * doc/invoke.texi: Add -march=cascadelake.
>
> gcc/testsuite/
>       * gcc.target/i386/funcspec-56.inc: Handle new march.

OK for mainline.

Thanks,
Uros.

> Wei Xiao <wei.william.xiao@gmail.com> 于2018年11月29日周四 下午4:32写道:
> >
> > Hi
> >
> > Distinguish based on stepping number is not recommended for some reasons:
> > 1) Intel doesn't officially disclose stepping information in SDM.
> > 2) Stepping can be changing in the future.
> >
> > We still prefer the conventional distinguish approach based on feature bits.
> > I have refined the patch as attached according to all your suggestions.
> >
> > Wei
> >
> >     gcc/
> >         * common/config/i386/i386-common.c (processor_names): Add cascadelake.
> >         (processor_alias_table): Add cascadelake.
> >         * config.gcc: Add -march=cascadelake.
> >         * config/i386/driver-i386.c
> >         (host_detect_local_cpu): Detect cascadelake.
> >         * config/i386/i386-c.c (ix86_target_macros_internal): Handle
> > cascadelake.
> >         * config/i386/i386.c (ix86_cost): Add m_CASCADELAKE.
> >         (processor_cost_table): Add cascadelake.
> >         (get_builtin_code_for_version): Handle cascadelake.
> >         (fold_builtin_cpu): Ditto.
> >         * config/i386/i386.h (TARGET_CASCADELAKE, PROCESSOR_CASCADELAKE): New.
> >         (PTA_CASCADELAKE): Ditto.
> >         * doc/extend.texi: Add cascadelake.
> >         * doc/invoke.texi: Add -march=cascadelake.
> >     gcc/testsuite/
> >         * g++.target/i386/mv16.C: Handle new march.
> >         * gcc.target/i386/builtin_target.c: Ditto.
> >         * gcc.target/i386/funcspec-56.inc: Ditto.
> >     libgcc/
> >         * config/i386/cpuinfo.c (get_intel_cpu): Handle cascadelake.
> >         * config/i386/cpuinfo.h: Add INTEL_COREI7_CASCADELAKE.
> > Wei Xiao <wei.william.xiao@gmail.com> 于2018年11月27日周二 下午6:40写道:
> > >
> > > Thanks for the helpful information!
> > > But I'm still checking with hardware team about the
> > > family/model/stepping numbers for Cascadelake which are not officially
> > > disclosed by Intel (to my best knowledge).
> > >
> > > Wei
> > > Martin Liška <mliska@suse.cz> 于2018年11月26日周一 下午10:00写道:
> > > >
> > > > On 11/26/18 12:18 PM, Jakub Jelinek wrote:
> > > > > On Mon, Nov 26, 2018 at 12:03:53PM +0100, Martin Liška wrote:
> > > > >>> For Cascade Lake the model number is the same as Skylake Server,
> > > > >>> it can only be distinguished based on the stepping (5 vs 4)
> > > > >>
> > > > >> Very interesting, probably the first time a distinguish is based on stepping number?
> > > > >
> > > > > Wouldn't it be better to distinguish it based on availability of VNNI, like
> > > > > we do for unknown family/model?
> > > > >
> > > > >>> Like gcc -mcpu=native needs to learn about this.
> > > > >>
> > > > >> I'm attaching patch that does that. Note that it's completely untested as I don't have
> > > > >> access to any of the new machines (Skylake server).
> > > >
> > > > Would be possible, the only ugly place would be in libgcc/config/i386/cpuinfo.c where we
> > > > call:
> > > >
> > > >       get_intel_cpu (family, model, stepping, brand_id);
> > > >       /* Find available features. */
> > > >       get_available_features (ecx, edx, max_level, &avx512_vnni);
> > > >
> > > > one would need a feature to distinguish CPU model. Do we really want that?
> > > >
> > > > Martin
> > > >
> > > > >
> > > > >       Jakub
> > > > >
> > > >


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