Say you have a searchbar, and for some reason you want to put a clear button over top of it.

Screen Shot 2017-01-11 at 6.05.16 AM.png

Shift select so you have both the searchbar and button selected, then hit the ‘Align’ layout tool and add the following constraints there.

Screen Shot 2017-01-11 at 6.14.10 AM.png

Screen Shot 2017-01-11 at 6.14.19 AM.png

And then Cmd + Alt + = to have them update/flush and align.

Screen Shot 2017-01-11 at 6.14.57 AM.png