https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70064
--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> --- The comment in the source says pretty much that -mred-zone defines a new ABI for ia32, and that user is responsible to make sure the stack in the red zone is preserved. In non-leaf functions, I believe red zone is not used anyway, or at least can't be used to store data across calls. The problem with the PIC setup sequence is that it actually is a call, but doesn't make the function non-leaf. Which is why I wrote #c5.
