Not optimized:

define i32 @"\01+[__ConsoleApplication15_Program Main:]"(%._ConsoleApplication15.Program*, i8*, %._Foundation.NSString**) #0 !dbg !4 {
BasicBlock0:
  %x = alloca i1
  %3 = alloca %._Foundation.NSString**, align 8
  %4 = alloca %._ConsoleApplication15.Program*
  store %._ConsoleApplication15.Program* %0, %._ConsoleApplication15.Program** %4
  store %._Foundation.NSString** %2, %._Foundation.NSString*** %3
  store i1 true, i1* %x, !dbg !46
  %5 = load i1, i1* %x, !dbg !47
  %6 = xor i1 %5, true, !dbg !47
  call void (%._Foundation.NSString*, ...) @NSLog(%._Foundation.NSString* bitcast (%struct.NSConstantString* @_unnamed_cfstring_1 to %._Foundation.NSString*), i1 %6), !dbg !47
  ret i32 0

BasicBlock1:                                      ; No predecessors!
  unreachable, !dbg !48
}

Optimized:

; Function Attrs: uwtable
define i32 @"\01+[__ConsoleApplication15_Program Main:]"(%._ConsoleApplication15.Program* nocapture readnone, i8* nocapture readnone, %._Foundation.NSString** nocapture readnone) #0 {
BasicBlock0:
  tail call void (%._Foundation.NSString*, ...) @NSLog(%._Foundation.NSString* bitcast (%struct.NSConstantString* @_unnamed_cfstring_1 to %._Foundation.NSString*), i1 false)
  ret i32 0
}