relaxed memory model function attribute

[Bruce Carneal]

Would an @restrict function attribute that applied to all ptr and 
slice arguments be hard to implement?

I'd use this on most if not all of my performance critical 'leaf' 
functions for both auto-vec and dcompute environments.  Nested 
functions accepting individual @restrict pointer arguments are an 
OK alternative but when working with multiple inputs and outputs 
things get a little tangled.