OptView2 - helping the compiler generate better code

Ofek Shilon

60 minute session
11:00-12:00, Wednesday, 6th July 2022

We will present a little known tool in the LLVM eco system that enables visibility into compiler optimization decisions. The original tool, opt-viewer, was intended mostly for compiler developers, and so we will focus mostly on its 2nd generation - OptView2 - which is designed with application developers in mind.

About 50% of the time would be dedicated to real examples of missed optimizations. Most of these turn out to be aliasing related, and so we will devote some time to discuss and study aliasing in some depth. We will demonstrate various techniques to interpret the compiler feedback and intervene in its decisions when you disagree.

If you care about performance, there's an excellent chance you'd leave this talk with immediately actionable insights and surprising ways to check and improve your code in performance bottlenecks.


Ofek Shilon

A Mathematics MA by training, but a 20Y C++ practitioner and speaker by practice. Special interests include low level optimizations, computational geometry and vision.