between range optimization bug (between with const on one end only)

mysql-test/r/range.result

@@ -232,7 +232,7 @@ update t1 set y=x;
 explain select * from t1, t1 t2 where t1.y = 2 and t2.x between 7 and t1.y+0;
 table	type	possible_keys	key	key_len	ref	rows	Extra
 t1	ref	y	y	5	const	1	Using where
-t2	ALL	x	NULL	NULL	NULL	9	Using where
+t2	range	x	x	5	NULL	4	Using where
 explain select * from t1, t1 t2 where t1.y = 2 and t2.x >= 7 and t2.x <= t1.y+0;
 table	type	possible_keys	key	key_len	ref	rows	Extra
 t1	ref	y	y	5	const	1	Using where

sql/opt_range.cc

@@ -794,18 +794,15 @@ static SEL_TREE *get_mm_tree(PARAM *param,COND *cond)
       DBUG_RETURN(new SEL_TREE(SEL_TREE::ALWAYS));
     DBUG_RETURN(new SEL_TREE(SEL_TREE::IMPOSSIBLE));
   }
+
   table_map ref_tables=cond->used_tables();
-  if (ref_tables & ~(param->prev_tables | param->read_tables |
-		     param->current_table))
-    DBUG_RETURN(0);				// Can't be calculated yet
   if (cond->type() != Item::FUNC_ITEM)
   {						// Should be a field
     if (ref_tables & param->current_table)
       DBUG_RETURN(0);
     DBUG_RETURN(new SEL_TREE(SEL_TREE::MAYBE));
   }
-  if (!(ref_tables & param->current_table))
-    DBUG_RETURN(new SEL_TREE(SEL_TREE::MAYBE)); // This may be false or true
+
   Item_func *cond_func= (Item_func*) cond;
   if (cond_func->select_optimize() == Item_func::OPTIMIZE_NONE)
     DBUG_RETURN(0);				// Can't be calculated
@@ -847,6 +844,12 @@ static SEL_TREE *get_mm_tree(PARAM *param,COND *cond)
     DBUG_RETURN(0);				// Can't optimize this IN
   }
 
+  if (ref_tables & ~(param->prev_tables | param->read_tables |
+		     param->current_table))
+    DBUG_RETURN(0);				// Can't be calculated yet
+  if (!(ref_tables & param->current_table))
+    DBUG_RETURN(new SEL_TREE(SEL_TREE::MAYBE)); // This may be false or true
+
   /* check field op const */
   /* btw, ft_func's arguments()[0] isn't FIELD_ITEM.  SerG*/
   if (cond_func->arguments()[0]->type() == Item::FIELD_ITEM)