| //===--- BitCount.swift ---------------------------------------------------===// |
| // |
| // This source file is part of the Swift.org open source project |
| // |
| // Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors |
| // Licensed under Apache License v2.0 with Runtime Library Exception |
| // |
| // See https://swift.org/LICENSE.txt for license information |
| // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // This test checks performance of Swift bit count. |
| // and mask operator. |
| // rdar://problem/22151678 |
| import Foundation |
| import TestsUtils |
| |
| public let BitCount = BenchmarkInfo( |
| name: "BitCount", |
| runFunction: run_BitCount, |
| tags: [.validation, .algorithm]) |
| |
| func countBitSet(_ num: Int) -> Int { |
| let bits = MemoryLayout<Int>.size * 8 |
| var cnt: Int = 0 |
| var mask: Int = 1 |
| for _ in 0...bits { |
| if num & mask != 0 { |
| cnt += 1 |
| } |
| mask <<= 1 |
| } |
| return cnt |
| } |
| |
| @inline(never) |
| public func run_BitCount(_ N: Int) { |
| var sum = 0 |
| for _ in 1...1000*N { |
| // Check some results. |
| sum = sum &+ countBitSet(getInt(1)) |
| &+ countBitSet(getInt(2)) |
| &+ countBitSet(getInt(2457)) |
| } |
| CheckResults(sum == 8 * 1000 * N) |
| } |
