grammar - What is being abbreviated as っちゃあ in 「忙しいっちゃあ忙し いけど…」?

I see the pattern [Adj1]っちゃあ[Adj1]（けど） relatively often, and I know that I've learned it before... I even know what it means. ...but what is it an abbreviation of? It is an abbreviation of something, right?

I've thought maybe ～といえば～ or ～というのは～, or something else along those lines, but 1) none of them seem to feel right to me, and 2) there aren't any relevant results on Google with those, so I assume (perhaps incorrectly?) that they're incorrect.

So what is っちゃあ?