Propeller does this kind of: https://github.com/google/llvm-propeller/blob/main/Docs/OptimizeClangO3WithPropeller.md https://github.com/google/llvm-propeller/bl

Propeller does this kind of: https://github.com/google/llvm-propeller/blob/main/Docs/OptimizeClangO3WithPropeller.md https://github.com/google/llvm-propeller/blob/main/Docs/Opti... It doesn't work online on the running code, but does on already compiled binaries. You can't move things after loading, without the application helping you, because the function pointers may be saved already. But you could optimise between runs. Alternatively, jits can already do pgo.