[Bug fortran/54462] [4.8 Regression] Another "segmentation fault" after an error in COMMON statement after r190853

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54462

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |burnus at gcc dot gnu.org

--- Comment #1 from Tobias Burnus <burnus at gcc dot gnu.org> 2012-09-03 
09:01:55 UTC ---
Rather obvious but untested draft patch:

--- a/gcc/fortran/symbol.c
+++ b/gcc/fortran/symbol.c
@@ -2922,4 +2922,6 @@ gfc_undo_symbols (void)
-
-                 st.name = st0->name;
-                 gfc_delete_bbt (&p->ns->common_root, &st, compare_symtree);
-                 free (st0);
+                 if (st0)
+                   {
+                     st.name = st0->name;
+                     gfc_delete_bbt (&p->ns->common_root, &st,
compare_symtree);
+                     free (st0);
+                   }