On Wed, Mar 26, 2008 at 7:36 PM, Andrew Haley <[EMAIL PROTECTED]> wrote: > Fran Baena wrote: > > > what are the advantages and inconvenients of get RTL from SSA rather > > than GIMPLE (previously translated from SSA)? > > It would mean that the expander would have to understand and unpick > SSA-specific stuff like PHI-nodes. It could be done, but I sure can't > think of any reason you'd want to.
You'd want to avoid translating from tuples back to nested trees. Instead when expanding from SSA form (ok, let's make that "semi"-SSA form that just keeps the UD chains but gets rid of PHI nodes (and maybe overlapping life ranges)) the expander can do expression combining by following the UD chain instead of relying on complex expressions re-constructed by TER. My understanding is that this will (sort of) happen at the moment we get the tuples branch merged. Richard.
