tree-ssa status

[law@redhat.com]

In message <87lm015pgo.fsf@egil.codesourcery.com>, Zack Weinberg writes:
 >law@redhat.com writes:
 >
 >> Also keep in mind the change to carry file/line information in a common
 >> location touched a lot of code in basically mindless ways.
 >
 >That might be a candidate for a separate merge to mainline (he says,
 >not having looked at the code at all).
I wouldn't recommend it.  The tree-ssa code has very different characteristics
in terms of how file/line information is carried around when compared to
the mainline sources.  As a result, the tradeoffs for which scheme is more
memory efficient are very different.

I did the algebra for the mainline a while back and concluded that the scheme
used by tree-ssa won't make sense for the mainline if/until tree-ssa is the
mainline.

Jeff