Comment by throwaway161220

There's a JIT branch in the official upstream emacs repository. Just checkout nick.lloyd-bytecode-jit after cloning emacs from git and run `./configure --with-jit` once you have libjit (originally a part of GNU dotNET) to give it a try. libjit doesn't install a .pc file so you'll have to explicitly set the LIBJIT lib and C ./configure flags if you install libjit from source.