Madreds does give you attack speed :P And the infiniti's is just there, because I wanted to fill the last spot. It's usually GG by the time you get bloodthirster.

I want to plus you just for the name xD

i dont really see a flaw with this build other than that you have to get some more AS to proc your passive before you attempt to build Madreds. Then you have more potency whilst your earning that 3k towards madreds that gives you no AS. Maybe, therefore, swap madreds with starks?

Also I would get black cleaver at some point, especially over infinity edge if a anything.