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Re: [tree-ssa] New type-based aliasing (was: More CFG improvements)
On Thu, 06 Feb 2003, Daniel Berlin wrote:
> Fully pruned SSA form is probably not a good idea.
> 1. It requires global liveness analysis
> 2. There are plenty of examples of optimizations that are missed on
> fully pruned SSA that aren't missed on semi-pruned or minimal.
I want to have the option of switching between semi-pruned and
pruned. Some heuristic that says something like "oh, hell, no
way we are inserting a gazillion PHI nodes in this graph".
I had forgotten about #2, but now that you mention both Cytron
and Briggs show the GVN example. I found references supporting
having all three forms (IBM's Jikes RVM).