https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65167
--- Comment #5 from Uroš Bizjak <ubizjak at gmail dot com> --- (In reply to Ilya Enkovich from comment #4) > ix86_function_arg_regno_p doesn't recognize bnd registers as args. Also > avoid_func_arg_motion doesn't work for BNDSTX because it is not a single > set. > > This patch works for reproducer: > + if (TARGET_MPX && BND_REGNO_P (regno)) No need for TARGET_MPX check, there will be no bnd regs when this flag is cleared.