The are two versions of count_leading_zeros and count_set_bits. They have the same types, but their native code implementations differ.
The first version inputs a tagged integer and the second version inputs an untagged integer. Generally, the first version (operating on a tagged integer) is faster, but if the untagged integer is already available in the surrounding context, the second version may be faster.
count_leading_zeros n returns the number of most-significant zero bits before the most significant set bit in n. If n is 0, the result is the number of bits in n, that is 31 or 63, depending on the target.
count_leading_zeros2 n computes the same result as count_leading_zeros n.
The functions only differ in optimizations that the compiler may be able to perform around the call. In particular, the implementation of count_leading_zeros n may operate directly on tagged n.
count_set_bits2 n computes the same result as count_set_bits n.
The functions only differs in optimizations that the compiler may be able to perform around the call. In particular, the implementation of count_set_bits n may operate directly on tagged n.