[FabHK]

You might be thinking about a different book? Hacker's Delight is mostly about bit fiddling (counting bits, finding the longest string of 1-bits, multiplication and division, Gray code, CRC, the famous approximate reciprocal square root) and such.

[EdwardCoffin]

These are just the kinds of things that an optimizing compiler can use, so would be quite useful for reverse engineering the product of an optimizing compiler to figure out what it is doing.