treelang fix for rs6000 / treelang not proper front end

[Jeff Sturm]

On Tue, 10 Jun 2003, Tim Josling wrote:
> Personally I like to build my own language specific parse tree and then
> rtl-ize it in a separate module. I did this with my cobol compiler.

Is that really much different than building a language-specific parse tree
then calling some module to genericize it?

My understanding from the tree-ssa presentations is that the important RTL
optimizers won't be maintained long-term, so I wouldn't want to count on
them in a new frontend.

Jeff