List of simplifications we should perform

[Richard Kenner]

    I just posted the gensimplify stuff to gcc-patches. You might want to
    look at it before adding more stuff to simplify-rtx.
    It just 'feels' a lot easier writing these simplifications in an md
    style, using match_operand, etc, than doing it in simplify rtx.

Maybe.  Although I agree it's a very neat idea, I'd want to think about
it more before agreeing with you that it's the best approach.

    Also, come to think of it, this would solve the problem of fold_rtx
    and simplify_rtx divergences.

No, because whichever way we go, fold_rtx would call simplify_rtx.

    We'd also be able to use the (define_simplify) syntax to generate TREE
    simplification code, i would imagine, no?

That would be a major advantage of the approach, but it would need some
work to get it going.