Crash on a simple join query with IS NULL and IS NOT NULL in where

CREATE TABLE t1 (a DATE, b INT, c INT, KEY(a), KEY(b), KEY(c)) ENGINE=MyISAM; 

CREATE TABLE t2 (d DATE) ENGINE=MyISAM; 

SELECT  * FROM t1,t2 WHERE  1 IS NOT NULL AND t1.b IS NULL;

DROP TABLE t1,t2;