Noalias trivia question

[T. William Wells]

Noalias is bad for a number of reasons, which I do not care to
discuss; however, you, terry at wsccs, seem to have an exaggerated
notion of what is possible for an optimizer to do.  Noalias
solves a problem which CANNOT be solved by an optimizer (yes,
this is another problem which can be shown to be equivalent to a
halting problem).  Please, before you flame others for supporting
things like this with comments like: "let the optimizer do it",
why don't you find out whether it is actually possible for the
compiler to do it?

(Another unsolvable problem: when will the programmer stop
flaming?  :-)