It won't, and shouldn't. Wasm meets very few of it's goals, and is nowhere near any native speeds under real world workloads. Even speedups with SIMD ar hindered, and the entire design and implementation of it in the clang/llvm compiler is very experimental.
Go work with wasm in the browser, you will pull your hair out at the fact emscripten is still the most used tool. It's all very hackey and if something breaks, you wont fix it.