[Bug fortran/50960] [OOP] vtables not marked as constant

["janus at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50960

--- Comment #1 from janus at gcc dot gnu.org 2011-11-02 11:57:44 UTC ---
(In reply to comment #0)
> < richi> and it seems the vtables are not initialized in a way the
>          optimizers could use them
> < richi> they are not constant

Right. I had thought of making them PARAMETERS earlier (to use Fortran
terminology). But in the early implementation this was not possible, since the
PPC members of the vtabs were not initialized statically. Now they are, so this
should work (in principle). I'll try if the following patch survives
regtesting:

Index: gcc/fortran/class.c
===================================================================
--- gcc/fortran/class.c (revision 180713)
+++ gcc/fortran/class.c (working copy)
@@ -424,7 +424,7 @@ gfc_find_derived_vtab (gfc_symbol *derived)
        {
          gfc_get_symbol (name, ns, &vtab);
          vtab->ts.type = BT_DERIVED;
-         if (gfc_add_flavor (&vtab->attr, FL_VARIABLE, NULL,
+         if (gfc_add_flavor (&vtab->attr, FL_PARAMETER, NULL,
                              &gfc_current_locus) == FAILURE)
            goto cleanup;
          vtab->attr.target = 1;