Re: Patch to allow Ada to work with tree-ssa

[Mark Mitchell <mark@codesourcery.com>]

Richard Kenner wrote:

>    Since Richard Henderson and Zack seem to think it's best, why don't you 
>    just create new tree nodes for these variable-length cases?  That seems 
>    to be the consensus point of view on how to solve the problem.
>
>Except that the authors of the optimizers haven't weighed in here yet
>and they were very much against adding new nodes to GIMPLE, which is
>what this would be doing.  Having played with some of that code, I can
>tell you that it won't be pleasant to add all the extra cases to
>deal with the additional nodes.
>
>Also, I'm told that over on IRC, the Fortran folks have ideas about
>what to do with some of the new fields.
>
>I think the memory cost argument in GIMPLE is very weak: only a very
>tiny fraction of GIMPLE nodes are ARRAY_REF and COMPONENT_REF.
>
>Your arguments about trees that are permanently kept around at the
>GENERIC level seems a far stronger argument and that's why I was thinking
>about having a different node for front-end use that corresponds to
>the shorter form.
>  
>
Well, that's certainly a place to start.  If you have both nodes, you 
can decide where to use one and where to use the other.  If you want to 
transition from the short form to the long form in the gimplifier, I 
think we can compromise on that.

-- 
Mark Mitchell
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mark@codesourcery.com