Finding the greatest power of 2 less than given integer

assuming that n is a 32-bit integer

if((n&(n-1))!=0) {
 n |= n >> 1; 
 n |= n >> 2; 
 n |= n >> 4; 
 n |= n >> 8; 
 n |= n >> 16;
 n=n+1;
}