// Copyright 2015 The Go Authors. All rights reserved. | |
// Use of this source code is governed by a BSD-style | |
// license that can be found in the LICENSE file. | |
// +build amd64,!appengine,!gccgo | |
package intsets | |
func popcnt(x word) int | |
func havePOPCNT() bool | |
var hasPOPCNT = havePOPCNT() | |
// popcount returns the population count (number of set bits) of x. | |
func popcount(x word) int { | |
if hasPOPCNT { | |
return popcnt(x) | |
} | |
return popcountTable(x) // faster than Hacker's Delight | |
} |