On Mon, Mar 19, 2007 at 09:27:25AM -0400, Diego Novillo wrote: > Manuel López-Ibáñez wrote on 03/17/07 14:28: > > > This is the project proposal that I am planning to submit to Google > > Summer of Code 2007. It is based on previous work of Jeffrey Laws, > > Diego Novillo and others. I hope someone will find it interesting and > > Yes, I can act as a mentor. > > I'm particularly interested in what we are going to do at -O0. Ideally, > I would try to build the SSA form and/or a predicated SSA form and try > to phrase the problem in terms of propagation of the uninitialized > attribute.
What worries me is that we can't afford to make -O0 run significantly slower than it does now. Cycle speeds are no longer increasing, we have to be very careful about slowing things down. But it does seem that predicated (or gated) SSA or something similar is needed to handle some of the most common cases we get wrong now (when the initialized-ness of a variable is completely correlated with the state of a boolean flag).
