🚀 go-pugleaf

brnstnd@kramden.acf.nyu.edu writes:
> I quote an article of mine from April:

: Hmmm, this doesn't sound right. After all, if A and B could be aliased,
: and B and C could be aliased, then A and C could be aliased. (This is
: why the natural keyword is ``alias,'' not ``noalias.'')

> I have always held the same position. You can see exactly the same
> position in many of my articles, and in my complaint that the Convex
> anti-aliasing mechanism makes the opposite assumption.

But, this is not correct.  Consider the example:

  extern void f(int * x, int * y, int * z);

  int a[3],b[3];
  ...
  f(a,a,b);
  f(a,b,b);
  ...

If you attempt to derive one summary for the aliasing that might
hold upon entry to "f" (i.e., without cloning specialized copies),
you discover that

  x may-alias y
  y may-alias z
  x NOT-alias z

David Chase
Sun Microsystems