Evaluate Profile-Guided Optimization (PGO) and LLVM BOLT

[zamazan4ik]

Hi!

Recently I checked Profile-Guided Optimization (PGO) improvements on multiple projects. The results are here. LLVM-related results are here. According to the tests, PGO usually helps with the compiler and compiler-like workloads (like static analysis). That's why I think trying to optimize Creusot with PGO can be a good idea.

I can suggest the following action points:

• Perform PGO benchmarks on Creusot. And if it shows improvements - add a note about possible improvements in Creusot's performance with PGO.
• Providing an easier way (e.g. a build option) to build scripts with PGO can be helpful for the end-users and maintainers since they will be able to optimize Creusot according to their own workloads.

Maybe testing Post-Link Optimization techniques (like LLVM BOLT) would be interesting too but I recommend starting from the usual PGO.

For the Rust projects, I suggest PGO optimizing with cargo-pgo.

[jhjourdan]

Performance is not (yet ?) an issue for the part of the code of Creusot written in Rust.