Fix gfortran.dg/class_to_type_4.f90 deallocation code misordering failure

	PR fortran/64986
gcc/fortran/
	* trans-expr.c (gfc_trans_assignment_1): Put component deallocation
	code at the beginning of the block.

From-SVN: r226162

gcc/fortran/ChangeLog

+2015-07-24  Mikael Morin  <mikael@gcc.gnu.org>
+
+	PR fortran/64986
+	* trans-expr.c (gfc_trans_assignment_1): Put component deallocation
+	code at the beginning of the block.
+
 2015-07-22  Mikael Morin  <mikael@gcc.gnu.org>
 
 	PR fortran/61831

gcc/fortran/trans-expr.c

@@ -9241,7 +9241,7 @@ gfc_trans_assignment_1 (gfc_expr * expr1, gfc_expr * expr2, bool init_flag,
   if (scalar_to_array && dealloc)
     {
       tmp = gfc_deallocate_alloc_comp_no_caf (expr2->ts.u.derived, rse.expr, 0);
-      gfc_add_expr_to_block (&loop.post, tmp);
+      gfc_prepend_expr_to_block (&loop.post, tmp);
     }
 
   /* When assigning a character function result to a deferred-length variable,