LLVM talks 1: Clang for Chromium

[Kagamin]

> The back end will evaluate them in different orders, as it is 
> more efficient to evaluate varargs functions from 
> right-to-left, and others from left-to-right. It's not an 
> insurmountable problem, it just needs to be worked on.

Are you taking about push vs mov? By default gcc preallocates 
space for arguments, evaluates them from left to right and 
`mov`es them to the stack. `push`es take more cycles, `mov`s take 
more space. Which of them is more efficient?