Patch: Prune unused DECL_STMTs from saved tree structure

Zack Weinberg
Tue Aug 29 23:38:00 GMT 2000

On Tue, Aug 29, 2000 at 07:10:18PM -0700, Mark Mitchell wrote:
> >>>>> "Zack" == Zack Weinberg <> 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.

Which is fine for what it used to be used for - but the pruning routine
has to eliminate all references to a given VAR_DECL in order for it to
be collected, so it has to examine the BLOCK_VARS chain.

There's no particular need to change it, I'm fine with walking down
BLOCK_VARS in the callback.

> 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.

No argument from me.


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