After seeing Adam's presentation on opt-viewer at the US dev conf late last year, I decided to whip up a quick demo project to show how it works. There's a continuous integration config file (Travis CI) that serves as a reference for its use.
GitHub - androm3da/optviewer-demo: Demonstration of LLVM's opt-viewer tool
Here's the analysis that was done on CPython v3.6.0:
https://androm3da.github.io/optviewer-demo/output_analysis/cpython/
-Brian