>>20
I don't know about ICC but MSVC is, although much better than Gucci, still pretty bad compared to what a human brain can do. There do not seem to be any compilers out there that can optimize register usage across the whole program, something that can greatly improve speed and space.
I've seen lots of little "WTF" moments when decompiling MSVC-compiled code. Things like clearing a register, then clearing it again even though it could never change between the two, useless pushes/pops, etc.