I glad to see you. 当你面对you说出来。
I glad to have seen you. 当你没有面对you说这句(已见过)，逻辑不通，没人用。
I am glad to have seen your mother. 你面对you提及your mother之事(我已见过她了)
.

时态的区别
to do 现在或将来
to have done是过去

to是表示现在或将来做的事， to have done表示过去已经做过的事。