side-effect-free-fns

[Eli Zaretskii]

The ELisp manual says in the node "Writing Emacs Primitives":

       If you define a function which is side-effect free, update the code
    in `byte-opt.el' which binds `side-effect-free-fns' and
    `side-effect-and-error-free-fns' so that the compiler optimizer knows
    about it.

I notice that none of the w32-* primitives are on that list, although
quite a few of them are side-effect free and error free.  Is there any
reason not to add those functions to byte-opt.el now?  Are there any
known dangers?

Is there anything else to determining whether a function can be added
to that list besides examining the code for absence of calls to
Fsignal and making sure it doesn't produce any effects except the
values it returns?