re PR c/39084 (ice on struct redefinition)

	PR c/39084
	* c-decl.c (start_struct): Return NULL on error.

From-SVN: r144067

gcc/ChangeLog

+2009-02-10  Steve Ellcey  <sje@cup.hp.com>
+
+	PR c/39084
+	* c-decl.c (start_struct): Return NULL on error.
+
 2009-02-10  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/39124

gcc/c-decl.c

@@ -5367,6 +5367,8 @@ start_struct (enum tree_code code, tree name)
 	    error ("redefinition of %<union %E%>", name);
 	  else
 	    error ("redefinition of %<struct %E%>", name);
+	  /* Don't create structures using a name already in use.  */
+	  ref = NULL_TREE;
 	}
       else if (C_TYPE_BEING_DEFINED (ref))
 	{