search for: pr21412

...prove that %add will never be 0 nor poison. This sounds hard for the > compiler to do, and I guess we'll have some regressions (e.g., LICM has to > be more conservative). Nevertheless, I'm all for fixing poison once and for > all! > Believe it or not, I already fixed this bug (PR21412). :) > > > BTW, would it help if I produced a version of Alive that implements the > semantics being proposed? (with no performance guarantees for this > prototype). The cool thing is that then we can run it through our database > of 300+ InstCombine optimizations and see whic...

Hello, What follows is my attempt to describe how poison works. Let me know what you think. -- David # LLVM Poison Semantics Poison is an LLVM concept which exists solely to enable further optimization of LLVM IR. The exact behavior of poison has been, to say the least, confusing for users, researchers and engineers working with LLVM. This document hopes to clear up some of the confusion