[Bug middle-end/17308] New: nonnull attribute not as useful as it could

["drepper at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>]

The nonnull function attribute seems to recognize only null values which are
explicitly passed to the marked function.  It would be helpful if deduced values
are also reported.  Example:

void *f(void *p) __attribute__((nonnull(1)));
void *bar(void *p)
{
  if (p == (void *) 0) return f(p);
  return p;
}

There compiler knows that p is NULL in the call of f.  The generated code proves
it.  Still no warning.

I see the same behavior with gcc 3.5.

-- 
           Summary: nonnull attribute not as useful as it could
           Product: gcc
           Version: 3.4.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: drepper at redhat dot com
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17308