[Bug tree-optimization/21368] New: VRP does not know that &s.a != NULL

["kazu at cs dot umass dot edu" <gcc-bugzilla at gcc dot gnu dot org>]

Consider

struct s {
  int a;
} s;

int
foo (void)
{
  int *p = &s.a;

  if (p == 0)
    return 123;

  /* Force VRP to run by having it insert at least one
     ASSERT_EXPR.  */
  *p = 456;

  return 0;
}

Note that with -fno-dominator-opts, VRP does not fold the "if" statement.

expr_computes_nonzero could use get_base_address.

-- 
           Summary: VRP does not know that &s.a != NULL
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: kazu at cs dot umass dot edu
                CC: dnovillo at redhat dot com,gcc-bugs at gcc dot gnu dot
                    org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21368