black cleaver irelia

yesterday i was in a game where i ended up behind( extremely) a poppy as irelia. I was highly tilted and ended up building black cleaver to jsut try it since our comp was full ad and poppy was doing poppy things. In combination with irelias new attack speed passive it actually seemed insanely strong in that instance. Ended up building deatsh dance and wits end to close out the game. I was curious if anyone had any thoughts on this