blob: 25c02f4fdcd88a25caee98a6e41d1b0bd281dcd6 [file] [log] [blame]
// 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.
//go:build amd64 && !appengine && !gccgo
// +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