https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117922
--- Comment #21 from Richard Sandiford <rsandifo at gcc dot gnu.org> --- I should have said, but: another reason for suggesting rtl-ssa is that it is usually self-updating. My long-term hope is that we'll be able to maintain it between passes, when we have consecutive passes that both use it. That isn't useful at the moment, because of the sparse usage, but it would become more useful if more passes use the framework. So in the long term, converting to rtl-ssa would mean that we might not need to build the whole IR for this pass individually. In contrast, doing local DF means that we would be committing to doing extra work for this pass in particular.
