[Bug tree-optimization/38826] points-to result wrong for reads from call-clobbered vars

["rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #1 from rguenth at gcc dot gnu dot org  2009-01-13 12:34 -------
It is interesting to see how taking the address of &s.q makes it a pointer
variable.  The fundamental issue seems to be that eliminating non-pointers
and their edges conflicts with field-sensitive analysis.

Consider

struct S { int *p; int *q; };

void foo (struct S **);

int *bar (int b)
{
  struct S s;
  struct S *p = &s;
  foo (&p);
  return s.q;
}

to see that just generating extra ADDRESSOF constraints for call arguments
will not fix the issue.

Not only we will need to avoid eliminating non-pointers / edges if any of a
variables sub-field has got a proper pointer label, unifying them (they
still have pointer label 0) is also wrong.

Danny, any idea where/how to fix this?


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dberlin at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38826