2 * HOST_BITS_PER_WIDE_INT bits. */
double_int double_int_mul (double_int, double_int);
+double_int double_int_mul_with_sign (double_int, double_int, bool, int *);
double_int double_int_add (double_int, double_int);
double_int double_int_sub (double_int, double_int);
double_int double_int_neg (double_int);