https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83312
--- Comment #1 from Marc Glisse <glisse at gcc dot gnu.org> --- Ironically, it seems to be the same pass, VRP1, that warns that some piece of code accesses pd_threads[j] for some negative j and later notices that the corresponding path is dead. I don't know if we can shift things a bit in the pass to avoid warning on code that the pass itself will remove.