Same error occurs on hppa. The "sync" instruction is simplest barrier on hppa, so the powerpc asm would work:
#elif defined(powerpc_HOST_ARCH) || defined(powerpc64_HOST_ARCH) \ || defined(powerpc64le_HOST_ARCH) __asm__ __volatile__ ("sync" : : : "memory"); -- John David Anglin dave.ang...@bell.net