I had this issue for a few hours and in the end I finally fixed it. IBCTT was eating up cpu and memory 5gb at one point and Xcode was unresponsive. I updated everything, cleared every cache and even tried throttling the tool but in the end the issue was simple but hard to detect. If that seems like your issue read on.
What you must do is clear all constraints on any view in the storyboard with errors if you are able to load it at least once. Then reset to suggested constraints and save.
If your storyboard has many views you want to Editor -> Refactor to storyboard the most complex or recently added/edited view.
You may notice in the crash report that it mentions an error not reporting a reason. Seems that I was having an error that I couldn't detect since the storyboard wouldn't load anyways. Refactoring out the view with the issue, then loading it first on a fresh restart showed the error and allowed me to clear constraints immediately.
Then restart Xcode by shutting down without force quitting to avoid the crash report and allow Xcode to start normally. Clear build folder then recompile.
This issue followed me through three installs of Xcode, 9.1 GM and 9.2 beta 1 and 2(9c34b) and a couple High Sierra beta updates (4 currently), so the issue seems to be deep within the AutoLayout engine. In all fairness to Apple constraints are a powerful idea but the variations involved on tools end has to be a nightmare.
Also my Interface Builder Cocoa Touch Tool is back to 84mb in Activity Monitor so I'm back to work....good luck!