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Re: Why is __i686 undefined for x86_64 -m32 (in mainline)
On Tue, Mar 16, 2010 at 2:06 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Tue, Mar 16, 2010 at 2:03 PM, Paolo Carlini <paolo.carlini@oracle.com> wrote:
>> On 03/16/2010 09:58 PM, Jakub Jelinek wrote:
>>> I don't think it is a good idea to change the meaning of the macros years
>>> after they have been introduced.
>>> You could add a different macro if you want.
>>> Why should be __i686 special? ?i686 does have __i586 features too, should it
>>> define also __i586, __i486?
>> Probably it should, in my opinion.
>>
>> But maybe I'm missing something about the whole logic of the recent
>> changes: wasn't about having the default for an i686 target similar, if
>> not identical, to passing by hand -march=i686? I'm really, really
>> confused... How is people supposed to figure out with macros that the
>> new default configuration supports everything -march=i686 supports vs
>> the previous status when it was identical to -march=i386?!?
>>
>> Paolo.
>>
>
> Checking __iX86 is a good idea for ISAs since it's meaning isn't well defined
I mean "isn't a good idea".
> nor enforced. ?For libstdc++ purpose, can you check __SSE2__ in addition to
> __i686?
>
>
> --
> H.J.
>
--
H.J.