Perhaps something along the lines of the compiler saying, "if you write this that way, then I know X is true and I can perform some more optimisations". But tha

Perhaps something along the lines of the compiler saying, "if you write this that way, then I know X is true and I can perform some more optimisations". But that may be even harder to do than a "compiler-friendly" language. We have two problems: people don't want to know about what's best for their processor (that's the job of the compiler after all), and they don't want to know about when compiler optimizations can take place (which actually is kind of the same problem).