Patch: Prune unused DECL_STMTs from saved tree structure

[Mark Mitchell]

>>>>> "Zack" == Zack Weinberg <zack@wolery.cumb.org> writes:

    Zack> Upon casual inspection of walk_tree I believe I can make it
    Zack> work.  I notice that it does not descend BLOCK_VARS - why
    Zack> not?

I think because they should always be reachable via DECL_STMT.

The truth is that I would like walk_tree to be a little tidier.  If we
defined tree structure a little more rigorously, we could organize in
it a DAG -- rather than the current cyclic structure.

--
Mark Mitchell                   mark@codesourcery.com
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