Enabling SSA for alpha?

[Jeffrey A Law]

  In message < 200003151846.NAA25538@polya.math.purdue.edu >you write:
  > > SSA is not suitable for direct code generation -- you translate into SSA,
  > > perform a series of transformations (optimizations), then translate back
  > > out of SSA.
  > 
  > OK, does this mean that the SSA pass transforms the code into a form that
  > the other passes can't deal with?
No it means that there is no way for the *processor* to implement the 
SSA form.  Read a little about SSA, particularly the PHI expressions that
must be inserted at dominance frontiers.  There's no processor in the
world that I'm aware of that implements the semantics of a PHI expression.
Nor do any of GCC's optimizers know about PHI expressions.

jeff