Re: Will tree-ssa be GCC 3.5?

[kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)]

    This strikes me as disingenuous.  The people working on the tree-ssa
    project have clearly and repeatedly stated their intention to replace
    several (perhaps most) of the RTL optimizers.  That this has not
    happened yet merely indicates that the project is not done yet.

Yes, I understand the intention, but I think the jury is very much
still out as to what extent that will be possible.

There are conflicting goals here.  In order to do the sorts of
optimizations best handled at higher level (e.g., Fortran loop
optimizers), you need to keep the tree at the highest level possible
for as long as possible during the optimization process.  But that
means the RTL generation will produce more things for RTL optimizers
to optimize.  I admittedly don't follow the tree-ssa project extremely
closely, but from what I see, it is far from clear how this dilemma
will be resolved and I suspect it will be an ongoing process for quite
some time.  So I think any prediction of removing a significant number
(and certainly *most*) of the RTL optimizers is premature.  Indeed, I
think that viewing that as a goal may get in the way of making the
best effort at the important high-level optimizations.