Fortran 2008 added a number of bit twiddling intrinsics[0].

Here are a few of the scalar intrinsics for bit counting.

  popcnt() - population count
  leadz() - leading zero
  trailz() - trailing zero
  poppar() - parity

[0] ftp://ftp.nag.co.uk/sc22wg5/n1701-n1750/n1729.pdf

Edited to fix formatting.