We're out of tree codes; now what?

Diego Novillo dnovillo@redhat.com
Tue Mar 13 22:08:00 GMT 2007


Doug Gregor wrote on 03/13/07 08:29:

> I don't know if we'll be able to get rid of *enough* tree codes,
> without going to some kind of two-level hierarchy. Some upcoming bits
> that will need more tree codes:

OpenMP clauses are already using a two level hierarchy.  One alternative
to try is to make this more widespread.

1- Keep very commonly used codes on the toplevel.
2- Create families of codes for less frequently used codes as it was
done with OMP clauses.

There was some other comment in this thread about tuples helping this.
They will not.  Tuples are not going to remove existing codes, in fact
they are going to be separate data structures at some point.  ATM, all
tuples are doing is adding one new tree code (which right now is
reserved by GIMPLE_MODIFY_STMT).

Code space problems are intrinsic for all the FEs that share the tree
structure.  Using two-level code spaces seems to me like a nice
alternative (provided that very commonly used codes are always in the
first level).

Either that or bite the bullet and use 16 bits while reducing tree_base
in other ways to minimize the memory growth.



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