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Re: [PATCH] Define HAS_CPUID/HAS_I586/HAS_I686 from -march=


On 08/18/2015 09:34 AM, H.J. Lu wrote:
> On Mon, Aug 17, 2015 at 10:24 PM, OndÅej BÃlka <neleai@seznam.cz> wrote:
>> On Mon, Aug 17, 2015 at 04:10:05PM -0700, H.J. Lu wrote:
>>> cpuid, i586 and i686 instructions are available if the processor
>>> specified by -march= supports them.  We can use this information
>>> to determine whether those instructions can be used safely.
>>>
>>> OK for master?
>>>
>> Patch itself looks ok. It fixes theoretical problem that if there would
>> be new processor without cpuid it would cause problem.
>>
>> But could you explain rationale? Here you replaced one like with
>> equivalent longer macro and HAS_I586 is never used. Do you plan followup
>> patches that use that?
> 
> I will use HAS_I586 and HAS_I686 in multi-arch for i486 and i586
> I am working on.

Does this include folding i486 up a directory and doing away with the
i386 support? Since we need the i486 instructions to implement NPTL.

https://sourceware.org/glibc/wiki/Development_Todo/Master#i386

Cheers,
Carlos.


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