RSSA backend

[Stephen Weeks]

> > 4. make the array initialization loops explicit in MACHINE; I guess this
> >     would be an insertArrayInitializations after insertSignalChecks
> > 
> > I think we eventually want 4, which solves all the problems at once.
> 
> Agreed.  I will do it right now.  It should be easy.

I checked in the array initialization stuff.  Go ahead and make one
more round of changes to the x86-codegen to turn off whatever you have
there, and then merge into the main trunk (cvs update -j rssa).  I'll
be very interested to see the combination of effects from knownCase
and RSSA, especially on self-compiles.