[Bug c++/25845] want optional warning for non-constant declarations that could be constant

["pinskia at physics dot uc dot edu" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #6 from pinskia at gcc dot gnu dot org  2006-01-18 16:29 -------
Subject: Re:  want optional warning for non-constant declarations that could be
constant


On Jan 18, 2006, at 11:19 AM, pcarlini at suse dot de wrote:

> ------- Comment #4 from pcarlini at suse dot de  2006-01-18 16:19 
> -------
> (In reply to comment #3)
>> const does nothing when it comes to local variables except for not 
>> letting you
>> touch it in other expressions.  It does nothing for optimizations or 
>> anything
>> else.
>
> This last point is not obvious at all, in my opinion. Why not? In 
> principle,
> certainly const-ness *can* help optimizers one way or the other. Is 
> this just a
> current limitation? A design choice? Anything in the standard making 
> that
> tricky? I would like to know more.


int f(const int *a, int *b)
{
   *b = 1;
   return *a;
}

a and b can alias and there is no way around that at all because that is
what the C++ standard says.

-- Pinski


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25845