Benchmark comparing guard vs. if let

BenchSwiftGuardWithIf.swift

import Foundation

var RUNS = 10
var COUNT = 10_000_000

// Extensions for prints

extension Sequence where Element: BinaryFloatingPoint {
    func average() -> Element {
        var i: Element = 0
        var total: Element = 0
        for value in self {
            total = total + value
            i += 1
        }
        return total / i
    }
}

// Profiler

final class Profiler {
  class func measure(_ closure: (() -> Void)!) -> TimeInterval {
    let startDate = Date()
    closure()
    let endDate = Date()
    let interval = endDate.timeIntervalSince(startDate)
    return interval
  }
}

// Test Data

var testData1: String? = "optional string"
var testData2: Int? = 999666

func testFunc(s:String, i:Int) -> Int {
    return 2+i
}

// Profilers

func testGuard(_ count: Int) -> TimeInterval {
    return Profiler.measure() {
        for _ in 1...COUNT {
            guard let test1 = testData1, let test2 = testData2 else {
                return
            }
            _ = testFunc(s: test1, i: test2)
        }
    }
}
    
func testIf(_ count: Int) -> TimeInterval {
    return Profiler.measure() {
        for _ in 1...COUNT {
            if let test1 = testData1, let test2 = testData2 {
                _ = testFunc(s: test1, i: test2)
            }
        }
    }
}

func warm() {
    for _ in 1...10_000 {
        _ = testFunc(s: fastRandomString(Int.random(in: 5...10)), i: Int.random(in: 0...1000))
    }
}
func fastRandomString(_ length: Int)->String{
    enum s {
        static let c = Array("abcdefghjklmnpqrstuvwxyz12345789")
        static let k = UInt32(c.count)
    }
    var result = [Character](repeating: "-", count: length)
    for i in 0..<length {
        let r = Int(arc4random_uniform(s.k))
        result[i] = s.c[r]
    }
    return String(result)
}

// Results

#if arch(i386) || arch(x86_64)
    print("Device x86_64\n")
#elseif arch(arm64)
    print("Device arm64\n")
#else
    print("Device Unknown\n")
#endif

// Important Warm
print("WARM please wait…\n")
warm()

// if
var results1 = [Double]()
for i in 1...RUNS {
    let t = testIf(COUNT)
    results1.append(Double(t))
    print("#\(i) IF \(t)")
}
print("IF runs \(RUNS) * \(COUNT) average \(String(describing: results1.average()))")
print("")
// guard
var results2 = [Double]()
for i in 1...RUNS {
    let t = testGuard(COUNT)
    results2.append(Double(t))
    print("#\(i) GUARD \(t)")
}
print("GUARD runs \(RUNS) * \(COUNT) average \(String(describing: results2.average()))")
// total
let (resultMin, resultMax) = (min(results1.average(), results2.average()), max(results1.average(), results2.average()))
print("\nDIFF \(1.0-resultMin/resultMax)")