https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114261
--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> --- Isn't the "scheduling window" limited somehow? Can we impose an upper bound on the number of dependences by placing a "virtual barrier" when we hit that limit? I don't know the structure of the scheduler or it's dependence analysis framework. In other places where GCC faces this usual quadraticness in dependence analysis we have such limits and try to cope with it as good as we can, worst give up completely.
