Warning: this is an internal module, and does not have a stable API or name. Functions in this module may not check or enforce preconditions expected by public modules. Use at your own risk!
Fast, unchecked bit shifting functions.
This is a workaround for poor optimisation in GHC 6.8.2. It fails to notice constant-width shifts, and adds a test and branch to every shift. This imposes about a 10% performance hit.
These functions are undefined when the amount being shifted by is greater than the size in bits of a machine Int#.