On 9/9/07, Mark Mitchell <[EMAIL PROTECTED]> wrote:
> Richard Guenther wrote:
>
> > I don't know of any place we would use such information. At least
> >
> > int *p = new int;
> > int *q = new int;
> > if (p == q)
> >
> > cannot be simplified as both pointers may be NULL?
>
> They cannot be NULL; new-expressions throw an exception if the
> allocation fails. (Of course, they could be NULL if you called the
> "nothrow" variant, or another "operator new" declared "throw()".)
>
> We should optimize away things like:
>
> int *p = new int;
> if (!p)
> cerr << "Could not allocate memory\n";
We don't I believe. We'd optimize
int *p = new int;
*p;
if (!p)
cerr << "Could not allocate memory\n";
though ;) Well, at least malloc is allowed to return NULL, so unless
we want to force all malloc attributed functions in C++ to throw exceptions
we cannot assume they return non-NULL (just on the basis they have
malloc attribute, that is).
Richard.
