Like ctlz, but extra-unsafe as it returns undef when given an x with value 0.

This intrinsic does not have a stable counterpart.

Examples

#![feature(core_intrinsics)]
# #![allow(internal_features)]

use std::intrinsics::ctlz_nonzero;

let x = 0b0001_1100_u8;
let num_leading = unsafe { ctlz_nonzero(x) };
assert_eq!(num_leading, 3);