title: Dismiss VC very slow due to autolayout and lots of subviews
body: <p>I have a scrollview loaded with lots of subviews, and for reasons I won't go into, I opted against <code>cell</code> re-use and a <code>UITableView</code>. It works well, save for a little initial main thread lag when the view is populated. However, every time a VC <code>"on top"</code> is dismissed (<code>e.g. after presenting a modal overtop</code>), there is a significant delay (2-3 seconds). I ran it through the profiler and the stack trace delves very deeply into IOS / Autolayout, as seen in the attached image.</p>
  
  <p>The code seems to go into
   <code>NSLayoutConstraint("+0x06 calll               "-[NSLayoutConstraint _addToEngine:]+0x0b")</code>. </p>
  
  <p>Is there anything I can do to bypass this apparent re-application of constraints?</p>
  
  <p><img src="https://i.stack.imgur.com/TueVR.jpg" alt="dat stack"></p>