Read this lengthy incompatibility EF lens list with the EOS M (when the EF adaptor is added) and I am shocked!

http://support-cn.canon-asia.com/contents/CN/ZH/8201705900.html
(in Chinese)

Even the lens is compatible, the AF speed of the new Canon mirrorless is just terribly sloooow, even when it is worked with the latest Canon EF-M STM lenses, which are specifically designed for the EOS M! :-o