[strmpnk]

It does apply to Elixir. It will help all around performance but more so it does this on a per-instruction level by reducing dispatch cost in that the interpreter pays (as well as managing to specialize things a little better than what the fixed instruction tables can express).

To get an idea of the instruction stream of the BEAM (not the same as .beam asm), you can use the erts_debug module:

    iex> :erts_debug.df(String)

This will dump a BEAM machine instruction stream to a file named Elixir.String.dis in your current working directory. You'll see things like:

    000000001B81AFB0: i_func_info_IaaI 0 `'Elixir.String'` `at` 2 
    000000001B81AFD8: is_integer_fx f(000000001B81AFB0) x(1) 
    000000001B81AFE8: is_ge_literal_fxc f(000000001B81B008) x(1) `0` 
    000000001B81B000: i_call_only_f loc(`'Elixir.String'`:`do_at`/2) 
    000000001B81B008: allocate_tt 2 2 
    000000001B81B010: move_window2_xxy x(1) x(0) y(0) 
    000000001B81B018: i_call_f loc(`'Elixir.String'`:`length`/1) 
    000000001B81B020: i_plus_xyjd x(0) y(0) j(0) x(0) 
    000000001B81B030: is_ge_literal_fxc f(000000001B81B060) x(0) `0` 
    000000001B81B048: move_shift_yxx y(1) x(0) x(1) 
    000000001B81B050: i_call_last_fQ loc(`'Elixir.String'`:`do_at`/2) 2 
    000000001B81B060: move_deallocate_return_cQ `nil` 2

Each of those instructions are what the .beam file loader currently generates. With the JIT, these will be replaced by machine code.