Re: [RFC] Contributing tree-ssa to mainline

[Theodore Papadopoulo <Theodore.Papadopoulo@sophia.inria.fr>]

kenner@vlsi1.ultra.nyu.edu said:
> A case I know about in Ada is check elimination.  Because the default
> for Ada is enabling checking, it's quite important to eliminate checks
> that can be proven not to fail.  Theoretically, a lot this could be
> language-independent optimizers by value range propagation and related
> optimizations.  But the front-end can do a much better job because it
> has information only it knows. Moreover, by suppressing the check
> before generating any code for it, compilation time is reduced.  I
> think this is clearly the proper place for that optimization.

AFAIK, tree-ssa would be beneficial in this situation. By making the 
check elimination work on GIMPLE (I hope it is the proper place), 
this would remove this from the ADA front-end and generalize to other 
languages. I assume that the sole introduction of optimization on 
trees allow you to move some code out of the front-end to the tree 
optimization passes of tree-ssa.

That being said, as an exterior observer, what I can say is that we 
have seen quite a few major contributors switching to tree-ssa recently...
This is surely partially because gcc-3.4 was in stage 3, but the move 
has been more marked than for previous releases 
IMHO.

Having the work-forces (rougthly) splitted in two is not a good thing IMO.
That should be considered...


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Theodore Papadopoulo
Email: Theodore.Papadopoulo@sophia.inria.fr Tel: (33) 04 92 38 76 01
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