CoffeeScript and JavaScript are semantically almost the same. CoffeeScript is not going to magically become faster because of asm.js. As I understand it, asm.js is really intended as a compiler target for languages with different semantics from JS that can achieve better performance by hinting more directly about what the machine should do.
Ah, I see. That's why GWT would really benefit from asm.js but coffeescript would not: the Java-source already contains the extra type information (that is currently being mostly ignored), whereas Coffeescript is just as dynamic as native JavaScript.
Not sure why I got downvoted for asking though. Oh well! Cheers.
