https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66737
--- Comment #6 from Ilya Enkovich <ienkovich at gcc dot gnu.org> --- (In reply to H.J. Lu from comment #5) > I don't think it is correct. Please see SPEC_64 and SPEC_32 defined > in gnu-user64.h. You should define MPX_SPEC with SPEC_64 and SPEC_32. It should be OK since we don't support MPX for other than m32 and m64. Will try with SPEC_64 also.