Division by a constant
Division by a constant can always be recast as multiplication by a constant followed by a shift.  The relevant papers are:

Robert Alverson, "Integer Division Using Reciprocals," IEEE Int'l Symp Comp Arithmetic, (ISCA-10):186-190, 1991.

Torbjörn Granlund and Peter L. Montgomery, "Division by Invariant Integers using Multiplication," ACM Conf on Prog Lang Dsgn and Impl, (PLDI-1994):61-72.

Daniel J. Magenheimer, Liz Peters, Karl W. Peters, and Dan Zuras, "Integer Multiplication and Division on the HP Precision Architecture," IEEE T. Comp., 37(8):980-990, August 1988.