https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80389
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> --- So, if there is a conflict between options, the backend should choose after warning the more important from those unless it wants to error, and then continue, so either change -march=armv8-a to something else, or change -mcpu=cortex-a57 to something else (or ignore).
