fold_builtin_memcpy cannot optimize <retval>?

[Andrew Pinski]

On Jan 21, 2005, at 2:37 PM, Mark Mitchell wrote:

> I'm not sure.  I seemed to believe in that thread that they could 
> never be NULL, but I'm not sure if everyone agreed, and I see that we 
> suggested a non-NULL tag on objects somewhere.  So, in that case, 
> there may be no difference at all to the middle-end.  In any case, I 
> think that it would make sense for us to allow a REFERENCE_TYPE 
> anywhere we allow a POINTER_TYPE.


Isn't this valid C++ then (or is it just undefined):
int &f(int *p)
{
   return *p;
}

extern "C" void abort (void);

int main()
{
   int &a = f(0);
   int *a1 = &a;
   if (a1 != 0)
     abort ();
   return 0;
}

If this is valid then REFERENCE_TYPE can be NULL even
in C++ as shown in the above testcase.  Yes this testcase is
something I just made up (and tested) but it just shows that
REFERENCE_TYPEs in C++ can be NULL.

-- Pinski