> Ive never been a big fan of having to call something to release > ssa_names, its too bug prone. I would much prefer to see something like > a cleanup pass done every once in a while... an ssa-name garbage > collector if you will :-). It seems to me that between major > optimization passes, any SSA_NAME with no defining stmt, no uses, and > isn't a default def of some sort can simply be released. Or at least > some similar set of criteria. I suspect immediate uses were not > available when release_defs was invented, so this was not easily done. Absolutely correct, we didn't have good access to the immediate uses when I added the SSA_NAME recycling.
It's also the case that the SSA graph updating after threading jumps is a lot more selective and should generate significantly less churn of SSA_NAME nodes than it used to do. So it may make sense to simply schedule collecting of unused SSA_NAMEs via the pass manager, possibly integrated with Pinski's trivial dead code elimination. jeff
