Hi Uros,

在 2026/6/16 16:52, Kewen Lin 写道:
> Hi Uros,
> 
> 在 2026/6/16 15:40, Uros Bizjak 写道:
>> On Tue, Jun 16, 2026 at 4:49 AM Kewen Lin <[email protected]> wrote:
>>>
>>> Hi,
>>>
>>> Authored-by: Xin Liu <[email protected]>
>>>
>>> Add c86-4g-m8 as a new HYGON Family 18h model 8 processor.  It
>>> inherits the c86-4g-m7 ISA set and most tuning decisions, including
>>> the same processor costs and scheduling model baseline.
>>>
>>> The patch wires c86-4g-m8 into the common x86 processor tables,
>>> driver CPU detection, target macros, --with-arch/--with-cpu handling,
>>> builtin CPU detection and documentation.  It also extends the c86-4g
>>> tuning masks that already special-case c86-4g-m7 to cover c86-4g-m8.
>>>
>>> For scheduling, rename the shared scheduling description file from
>>> gcc/config/i386/c86-4g-m7.md to gcc/config/i386/c86-4g-m7m8.md and
>>> reuse the c86-4g-m7 scheduling reservations for c86-4g-m8 where the
>>> latency and resource usage are the same.  Add separate c86-4g-m8
>>> reservations for the few operations with different latency.  This patch
>>> does not affect genautomata build time.
>>>
>>> Bootstrapped and regtested on a hygon c86-4g-m7 machine, as well as
>>> a cfarm x86-64 machine.
>>>
>>> Is it ok for trunk?  Also ok to backport to gcc-16/gcc-15 after burn-in
>>> time?
>>
>> OK with some minor inconsistencies resolved (see inline), also OK for
>> backports after some time in mainline.
>>
>> Thanks,
>> Uros.
>>
>>>
[snip ....]>>> diff --git a/gcc/common/config/i386/cpuinfo.h 
b/gcc/common/config/i386/cpuinfo.h
>>> index 62e9210b067..f59090c8cde 100644
>>> --- a/gcc/common/config/i386/cpuinfo.h
>>> +++ b/gcc/common/config/i386/cpuinfo.h
>>> @@ -383,6 +383,12 @@ get_hygon_cpu (struct __processor_model *cpu_model,
>>>           CHECK___builtin_cpu_is ("c86-4g-m7");
>>>           cpu_model->__cpu_subtype = HYGONFAM18H_C86_4G_M7;
>>>         }
>>> +      else if (model == 0x8)
>>
>> This condition is inconsistent with the condition in driver-i386.cc, where
>>
>> else if (model >= 8) // open-ended
>>    processor = PROCESSOR_C86_4G_M8;
>>
>> I think this should be (model >= 0x8) so a hypothetical model 9 would
>> get m8 tuning.
> 
> As the else if hunk has a CHECK for exact m8, it was intentional to keep
> the checking for "== 8" only.  Does it sound reasonable?
> 

With the above explanation, do you still prefer to keep the consistency with
driver-i386.cc, or agree it's fine to leave them incosistent?

BR,
Kewen

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