diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
index 03edb8026a8..40df317d681 100644
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -83,6 +83,7 @@ static void make_setop_translation_list(Query *query, Index newvarno,
 							List **translated_vars);
 static bool is_simple_subquery(Query *subquery, RangeTblEntry *rte,
 				   JoinExpr *lowest_outer_join,
+				   bool will_need_phvs,
 				   bool deletion_ok);
 static Node *pull_up_simple_values(PlannerInfo *root, Node *jtnode,
 					  RangeTblEntry *rte);
@@ -691,7 +692,11 @@ pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
 		 */
 		if (rte->rtekind == RTE_SUBQUERY &&
 			is_simple_subquery(rte->subquery, rte,
-							   lowest_outer_join, deletion_ok) &&
+							   lowest_outer_join,
+							   (lowest_nulling_outer_join != NULL ||
+								containing_appendrel != NULL ||
+								root->parse->groupingSets),
+							   deletion_ok) &&
 			(containing_appendrel == NULL ||
 			 is_safe_append_member(rte->subquery)))
 			return pull_up_simple_subquery(root, jtnode, rte,
@@ -955,7 +960,11 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
 	 * pull_up_subqueries_recurse.
 	 */
 	if (is_simple_subquery(subquery, rte,
-						   lowest_outer_join, deletion_ok) &&
+						   lowest_outer_join,
+						   (lowest_nulling_outer_join != NULL ||
+							containing_appendrel != NULL ||
+							parse->groupingSets),
+						   deletion_ok) &&
 		(containing_appendrel == NULL || is_safe_append_member(subquery)))
 	{
 		/* good to go */
@@ -1023,6 +1032,14 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
 	rvcontext.rv_cache = palloc0((list_length(subquery->targetList) + 1) *
 								 sizeof(Node *));
 
+	/*
+	 * The next few stanzas identify cases where we might need to insert
+	 * PlaceHolderVars.  These same conditions must be checked by callers of
+	 * is_simple_subquery(): pass will_need_phvs = true if anything below
+	 * would set rvcontext.need_phvs = true.  Else we can find ourselves
+	 * trying to generate a PHV with empty phrels.
+	 */
+
 	/*
 	 * If we are under an outer join then non-nullable items and lateral
 	 * references may have to be turned into PlaceHolderVars.
@@ -1433,11 +1450,14 @@ make_setop_translation_list(Query *query, Index newvarno,
  * (Note subquery is not necessarily equal to rte->subquery; it could be a
  * processed copy of that.)
  * lowest_outer_join is the lowest outer join above the subquery, or NULL.
+ * will_need_phvs is true if we might need to wrap the subquery outputs
+ * with PlaceHolderVars; see comments within.
  * deletion_ok is TRUE if it'd be okay to delete the subquery entirely.
  */
 static bool
 is_simple_subquery(Query *subquery, RangeTblEntry *rte,
 				   JoinExpr *lowest_outer_join,
+				   bool will_need_phvs,
 				   bool deletion_ok)
 {
 	/*
@@ -1489,7 +1509,7 @@ is_simple_subquery(Query *subquery, RangeTblEntry *rte,
 
 	/*
 	 * Don't pull up a subquery with an empty jointree, unless it has no quals
-	 * and deletion_ok is TRUE and we're not underneath an outer join.
+	 * and deletion_ok is true and will_need_phvs is false.
 	 *
 	 * query_planner() will correctly generate a Result plan for a jointree
 	 * that's totally empty, but we can't cope with an empty FromExpr
@@ -1504,9 +1524,8 @@ is_simple_subquery(Query *subquery, RangeTblEntry *rte,
 	 * But even in a safe context, we must keep the subquery if it has any
 	 * quals, because it's unclear where to put them in the upper query.
 	 *
-	 * Also, we must forbid pullup if such a subquery is underneath an outer
-	 * join, because then we might need to wrap its output columns with
-	 * PlaceHolderVars, and the PHVs would then have empty relid sets meaning
+	 * Also, we must forbid pullup if the subquery outputs would need
+	 * PlaceHolderVar wrappers; the PHVs would then have empty relids meaning
 	 * we couldn't tell where to evaluate them.  (This test is separate from
 	 * the deletion_ok flag for possible future expansion: deletion_ok tells
 	 * whether the immediate parent site in the jointree could cope, not
@@ -1514,6 +1533,9 @@ is_simple_subquery(Query *subquery, RangeTblEntry *rte,
 	 * fixed by letting the PHVs use the relids of the parent jointree item,
 	 * but that complication is for another day.)
 	 *
+	 * The caller must pass will_need_phvs = true under the same conditions
+	 * that would cause pull_up_simple_subquery to set need_phvs = true.
+	 *
 	 * Note that deletion of a subquery is also dependent on the check below
 	 * that its targetlist contains no set-returning functions.  Deletion from
 	 * a FROM list or inner JOIN is okay only if the subquery must return
@@ -1522,7 +1544,7 @@ is_simple_subquery(Query *subquery, RangeTblEntry *rte,
 	if (subquery->jointree->fromlist == NIL &&
 		(subquery->jointree->quals != NULL ||
 		 !deletion_ok ||
-		 lowest_outer_join != NULL))
+		 will_need_phvs))
 		return false;
 
 	/*
diff --git a/src/test/regress/expected/groupingsets.out b/src/test/regress/expected/groupingsets.out
index d052f365c70..036a1bce5b9 100644
--- a/src/test/regress/expected/groupingsets.out
+++ b/src/test/regress/expected/groupingsets.out
@@ -1677,27 +1677,25 @@ select v||'a', case when grouping(v||'a') = 1 then 1 else 0 end, count(*)
 -- test handling of outer GroupingFunc within subqueries
 explain (costs off)
 select (select grouping(v1)) from (values ((select 1))) v(v1) group by cube(v1);
-        QUERY PLAN         
----------------------------
- GroupAggregate
-   Group Key: $2
+           QUERY PLAN            
+---------------------------------
+ MixedAggregate
+   Hash Key: $1
    Group Key: ()
-   InitPlan 1 (returns $1)
-     ->  Result
-   InitPlan 3 (returns $2)
-     ->  Result
-   InitPlan 4 (returns $3)
-     ->  Result
    ->  Result
-   SubPlan 2
+         InitPlan 2 (returns $1)
+           ->  Result
+         InitPlan 3 (returns $2)
+           ->  Result
+   SubPlan 1
      ->  Result
-(12 rows)
+(10 rows)
 
 select (select grouping(v1)) from (values ((select 1))) v(v1) group by cube(v1);
  grouping 
 ----------
-        0
         1
+        0
 (2 rows)
 
 explain (costs off)
@@ -1723,4 +1721,37 @@ select (select grouping(v1)) from (values ((select 1))) v(v1) group by v1;
         0
 (1 row)
 
+-- check that we don't pull up when a phrel-less PHV would result
+explain (verbose, costs off)
+select ss.f from int4_tbl as i4 cross join lateral (select i4.f1 as f) as ss
+group by cube(ss.f) order by 1;
+                    QUERY PLAN                    
+--------------------------------------------------
+ Sort
+   Output: (i4.f1)
+   Sort Key: (i4.f1)
+   ->  MixedAggregate
+         Output: (i4.f1)
+         Hash Key: (i4.f1)
+         Group Key: ()
+         ->  Nested Loop
+               Output: (i4.f1)
+               ->  Seq Scan on public.int4_tbl i4
+                     Output: i4.f1
+               ->  Result
+                     Output: i4.f1
+(13 rows)
+
+select ss.f from int4_tbl as i4 cross join lateral (select i4.f1 as f) as ss
+group by cube(ss.f) order by 1;
+      f      
+-------------
+ -2147483647
+     -123456
+           0
+      123456
+  2147483647
+            
+(6 rows)
+
 -- end
diff --git a/src/test/regress/sql/groupingsets.sql b/src/test/regress/sql/groupingsets.sql
index dd41687faa6..b056a30873e 100644
--- a/src/test/regress/sql/groupingsets.sql
+++ b/src/test/regress/sql/groupingsets.sql
@@ -477,4 +477,11 @@ explain (costs off)
 select (select grouping(v1)) from (values ((select 1))) v(v1) group by v1;
 select (select grouping(v1)) from (values ((select 1))) v(v1) group by v1;
 
+-- check that we don't pull up when a phrel-less PHV would result
+explain (verbose, costs off)
+select ss.f from int4_tbl as i4 cross join lateral (select i4.f1 as f) as ss
+group by cube(ss.f) order by 1;
+select ss.f from int4_tbl as i4 cross join lateral (select i4.f1 as f) as ss
+group by cube(ss.f) order by 1;
+
 -- end