2019 LLVM Developers' Meeting

Interprocedural optimizations (IPOs) have been historically weak in LLVM. The strong reliance on inlining can be seen as a consequence or cause. Since inlining is not always possible (recursion, parallel programs, ...) or beneficial (large functions), the effort to improve IPO has recently seen an upswing again. In order to capitalize this momentum, we would like to talk about the current situation in LLVM, and goals for the immediate, but also distant, future.

We will ask our expert panel questions as follows:
- What are the current and potential problems with IPO?
- How does the new pass manager impact IPO?
- Is function cloning & IPO as an alternative to inlining?
- How does the desired (new PM) pipeline differ from what we have right now?
- How is, and how should, IPO interact with (thin-)LTO and PGO?
- What are the most desirable IPO analyses and optimizations we are lacking today?

This guided panel discussion is a follow-up to the BoF at EuroLLVM'19. Both experts and newcomers are welcome to attend. Questions can be send to the organizers prior to the conference to allow consideration.