A subset of this could possibly be applied at the wasm-opt level, but consider that at the LLVM's IR level there is more information to be leveraged (in particular PartialExecuter uses information on what memory ranges are read-only).
In general the whole concept behind Cheerp (C++ to WebAssembly + JavaScript compiler) is doing as much as possible at the LLVM IR level, JavaScript concept included, since it's easier and more powerful to do code transformation there.