x86

[Stephen Weeks]

> Has anything been done to fix the assumption that syntactially distinct
> memory locations are distinct?  This REALLY REALLY scares me.  It isn't just
> that it is incorrect, it is that often one will be able to get away with it.
> Thus these bugs can remain hidden for a long time.

A good reason to keep around the C backend for a while, so we can compare.  But,
I agree.  I think we (i.e. Matthew :-) need to look at the x86translate pass to
understand what kind of must-not alias information holds.  I don't mind taking
advantage of the fact that x86 only comes from machine and I think it would not
cost much in terms of performance.