Since Rust 1.37 the compiler supports profile-guided optimization (PGO), a feature that many power users have been asking for. However, so far the performance improvements enabled by PGO have been a bit underwhelming, even after fixing a bad interaction with Cargo. On the other hand, my sample of test applications is rather small.
So my question is: Did anybody try out PGO with their projects? Or would anyone here like to try it? You'd have to use at least Rust 1.39 (currently beta) in order to get a working Cargo version and then just follow the instructions in the official docs: https://doc.rust-lang.org/rustc/profile-guided-optimization.html#a-complete-cargo-workflow
In theory, LLVM's PGO can noticeably improve runtime performance (e.g. up to 10% for Firefox).