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Re: RFA: Adding a location_t (or pointer) to tree_exp for 3.4 only.

On Sat, 11 Oct 2003 wrote:

> In message <>, Richard Henderson writes:
>  >On Mon, Oct 06, 2003 at 04:14:23PM -0400, Daniel Jacobowitz wrote:
>  >> A number of places continue to recurse on the arguments of a PLUS_EXPR
>  >> but do not handle EXPR_WITH_FILE_LOCATION, for one thing.
>  >
>  >Please name such a place.  I'm asking for specifics here and
>  >getting nothing from yall.
>  >
>  >Have yall *tried* WFL and have experimental evidence for how much
>  >of a performance hit you get?  Given that we do extraordinarily
>  >little reasoning with trees on mainline, I have a hard time imagining
>  >that it has much affect at all.
> Ugh.  WFL nodes have certain properties that are very undesirable.  Their
> worst property is that you have to make sure you strip them away in all
> the locations that expect to see the underlying expression -- which is very
> prone to mistakes.

The second worst has to be that you have to "unstrip" them in order to
line info if you duplicate code through an optimization.

IE you strip them to process the underlying expression, then you need to
copy the WFL if you end up copying the underyling expression, or you lose
line info.

Since most, if not everything, doesn't WANT to see a WFL, only the
underlying expression, this usually means passing the WFL around too.

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