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

["sigra at home dot se" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #8 from sigra at home dot se  2006-01-18 19:29 -------
> 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.

In this case the compiler should warn because a could be declared "const int *
const" and b could be declared "int * const".


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