PREPARE/EXECUTE makes signed integer out of unsigned

CREATE TABLE t1 (

  `c1` bigint(20) UNSIGNED DEFAULT NULL

)ENGINE=SPIDER PARTITION BY LIST (`c1` MOD 4)

(PARTITION `pt0` VALUES IN (0)....);

insert into t1(c1) values (6800281190650363904), (17864960750176564435);

mysql> PREPARE p1 FROM 'select * FROM t1 WHERE c1 = ?';

Query OK, 0 rows affected (0.05 sec)

Statement prepared

mysql> EXECUTE p1 USING 17864960750176564435; # BUG HERE

Empty set (0.11 sec)

mysql> SELECT * FROM t1 WHERE c1 = 17864960750176564435; # CORRECT HERE

+----------------------+

| c1                   |

+----------------------+

| 17864960750176564435 |

+----------------------+

1 row in set (0.01 sec)