[RFC] Merge criteria for tree-ssa

[Mark Hahn]

> The criteria that makes most sense from a users viewpoint is that
> tree-ssa could not be merged until gfortran was as good as g77 at
> compiling f77.

as another user, I strongly disagree.  can't people with f77 code
simply compile with older versions of gcc?

gcc badly needs the optimization benefits promised by ssa, not to mention
support for f90, etc.  there's nothing wrong with temporary regressions 
that are a side-effect of progress elsewhere; in fact, it's just silly 
to think that quality should increase monotonically along every axis.

regards, mark hahn.