diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index d598c1b..926a41a 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -2638,43 +2638,38 @@ is_dummy_plan(Plan *plan)
  * the only good way to distinguish baserels from appendrel children
  * is to see what is in the join tree.
  */
-static Bitmapset *
-get_base_rel_indexes(Node *jtnode)
+static void
+get_base_rel_indexes(Node *jtnode, Bitmapset **result)
 {
-	Bitmapset  *result;
 
 	if (jtnode == NULL)
-		return NULL;
+		return;
 	if (IsA(jtnode, RangeTblRef))
 	{
 		int			varno = ((RangeTblRef *) jtnode)->rtindex;
 
-		result = bms_make_singleton(varno);
+		*result = bms_add_member(*result, varno);
 	}
 	else if (IsA(jtnode, FromExpr))
 	{
 		FromExpr   *f = (FromExpr *) jtnode;
 		ListCell   *l;
 
-		result = NULL;
 		foreach(l, f->fromlist)
-			result = bms_join(result,
-							  get_base_rel_indexes(lfirst(l)));
+			get_base_rel_indexes(lfirst(l), result);
 	}
 	else if (IsA(jtnode, JoinExpr))
 	{
 		JoinExpr   *j = (JoinExpr *) jtnode;
 
-		result = bms_join(get_base_rel_indexes(j->larg),
-						  get_base_rel_indexes(j->rarg));
+		get_base_rel_indexes(j->larg, result);
+		get_base_rel_indexes(j->rarg, result);
 	}
 	else
 	{
 		elog(ERROR, "unrecognized node type: %d",
 			 (int) nodeTag(jtnode));
-		result = NULL;			/* keep compiler quiet */
 	}
-	return result;
 }
 
 /*
@@ -2684,7 +2679,7 @@ static void
 preprocess_rowmarks(PlannerInfo *root)
 {
 	Query	   *parse = root->parse;
-	Bitmapset  *rels;
+	Bitmapset  *rels = NULL;
 	List	   *prowmarks;
 	ListCell   *l;
 	int			i;
@@ -2716,7 +2711,7 @@ preprocess_rowmarks(PlannerInfo *root)
 	 * make a bitmapset of all base rels and then remove the items we don't
 	 * need or have FOR [KEY] UPDATE/SHARE marks for.
 	 */
-	rels = get_base_rel_indexes((Node *) parse->jointree);
+	get_base_rel_indexes((Node *) parse->jointree, &rels);
 	if (parse->resultRelation)
 		rels = bms_del_member(rels, parse->resultRelation);