Open Radar

 
Summary:
Set  intersect and exclusiveOr methods performance has decreased in Xcode7.0 beta 5 (7A176x) with comparison to
 Xcode 6.4 (6E35b).

500_000 elements

Xcode 6.4 (6E35b) :
Interset 		- 0.06 sec
ExclusiveOr	- 0.12 sec

Xcode7.0 beta 5 (7A176x):
Interset 		- 1.16 sec
ExclusiveOr	- 1.22 sec

Steps to Reproduce:
Create 2 random sets and use intersect  and exclusiveOr methods

Code Example: 
func set_intersect(set: Set<Int>) {
  
  let otherSet = makeRandomSet(set.count)
  
  var res: Set<Int> = Set()
  measure("Intersect") {
    res = set.intersect(otherSet)
  }
  print(res.count)
}

func set_exclusiveOr(set: Set<Int>) {
  
  let otherSet = makeRandomSet(set.count)
  
  var res: Set<Int> = Set()
  measure("ExclusiveOr") {
    res = set.exclusiveOr(otherSet)
  }
  print(res.count)
}

func makeRandomSet(count: Int) -> Set<Int> {
  
  var set = Set<Int>(minimumCapacity: count)
  for _ in 0...count  {
    set.insert(Int(arc4random()))
  }
  return set
}


func measure(_ title: String? = nil, times: Int = 1, call: () -> Void) {
  var results = [CFTimeInterval]()
  for _ in 1...times {
    let startTime = CACurrentMediaTime()
    call()
    let endTime = CACurrentMediaTime()
    let time =  endTime - startTime
    results.append(time)
  }
  
  title.map { print("\($0) : ", appendNewline: false) }
  let avarage = results.reduce(0, combine: +) / Double(times)
  print("() Average - \(avarage)")
}

// Run test 

let set = makeRandomSet(5_000_000)

set_exclusiveOr(set)
set_intersect(set)

Expected Results:
performance should be the same of better.

Actual Results:
Performance is worse

Notes:
Examples project is attached.