http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54985
--- Comment #6 from Jeffrey A. Law <law at redhat dot com> 2012-10-19 22:00:45 UTC --- This is definitely something introduced when I extended the threading code last year. When threading across a backedge in the CFG we run the risk of simplifying a conditional using equivalences which are valid for one loop iteration, but not the next iteration. There's a bit of special casing done to handle this. We either need to add another case or actually invalidate the temporary equivalences we made for the statements in the loop. The first is pretty trivial, but I want to ponder the special case code over the weekend for it's overall safety/correctness. I don't see any difficulty wrapping this up early next week. Jeff
