antirez/redis — pull request #2124 by lmscsomg (2014-11-04 05:07:41+00:00)
Title: optimize the method: _dictNextPower

The optimized method may be more efficient:)

size & (size-1) /* if size is a power of two, the value is 0 */
size |= size-1; /* make all the bit 0 after the lastest bit 1 to be 1, e.g. 001100->001111 */