https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63361
--- Comment #14 from Jakub Jelinek <jakub at gcc dot gnu.org> --- grep FLT_EVAL_METHOD config/*/* says the only problematic arches are i?86, s390*, m68k*, arm and maybe aarch64. add-ieee-options has just i?86 and m68k (clearly wrong, because it really should not use [istarget i?86-*-*] but [check_effective_target_ia32] ieee.exp seems to do that properly. So, I think you should add -ffloat-store if ia32, or if m68k-*-*, and add -mieee if alpha* or sh*.
