var r [2]uint64
	var c uint64
	r[0], c = bits.Sub64(a[0], b[0], c)
	r[1], c = bits.Sub64(a[1], b[1], c)
	// s390x:"BRC\t[$]12,"
	if c == 1 {
		panic("overflow")
	}
	return r
}

func Sub64MPanicOnOverflowNE(a, b [2]uint64) [2]uint64 {
	var r [2]uint64
	var c uint64
	r[0], c = bits.Sub64(a[0], b[0], c)
	r[1], c = bits.Sub64(a[1], b[1], c)
	// s390x:"BRC\t[$]12,"
	if c != 0 {
		panic("overflow")
	}