1 files changed, 3 insertions, 2 deletions
diff --git a/vm.c b/vm.c
index 08c96d5393..d9ac0284f8 100644
--- a/vm.c
+++ b/vm.c
@@ -1147,8 +1147,9 @@ rb_vm_check_redefinition_by_prepend(VALUE klass)
 static void
 add_opt_method(VALUE klass, ID mid, VALUE bop)
 {
-    rb_method_entry_t *me;
-    if (st_lookup(RCLASS_M_TBL(klass), mid, (void *)&me) && me->def &&
+    rb_method_entry_t *me = rb_method_entry_at(klass, mid);
+
+    if (me && me->def &&
 	me->def->type == VM_METHOD_TYPE_CFUNC) {
 	st_insert(vm_opt_method_table, (st_data_t)me, (st_data_t)bop);
     }