g++ and aliasing bools

[Richard Kenner]

    Errr, not really.
    They just happen to be our representation of aliases for types.

In some sense, but they avoid undecidability problems because you just
need to look at language semantics, not run-time behavior of a
particular program.

The issue with alias sets is whether you can prove from the language
specification that two objects *cannot* alias each other.  If and only
if you can, they are in different alias sets.