> There can be no limitations of any kind in terms of expressing to the machine, precisely how the machine should behave.

I hear what you're saying but you're overselling C here. Straight up ANSI C has a lot of limitations in telling the machine what to do. Even the various proprietary extensions have limitations right up until you stop writing anything that looks a little bit like C, e.g. you start using "asm" style intrinsics that let you do assembly inline.