diff --git a/iseq.c b/iseq.c
index 800ea1f883..5d294e9d31 100644
--- a/iseq.c
+++ b/iseq.c
@@ -129,6 +129,11 @@ iseq_clear_ic_references_i(VALUE *code, VALUE insn, size_t index, void *data)
 
             if (rb_id_table_lookup(vm->constant_cache, id, (VALUE *) &ics)) {
                 st_delete(ics, (st_data_t *) &ic_data->ic, (st_data_t *) NULL);
+
+                if (ics->num_entries == 0) {
+                    rb_id_table_delete(vm->constant_cache, id);
+                    st_free_table(ics);
+                }
             }
 
             return true;