Is there an equivalent to "rehash" for autoloaded functions?

It's fine if they revert to being not-autoloaded-yet, just looking for a
simple solution other than "exec zsh -il" to get this effect.

I expect I can write something to this effect with "$functions_source[pip]"
and compare the ${filename:t} to the function name, but I expect there's
something for this already.

If not, where can I find instructions on how to contribute something like
this upstream, e.g. rehash_functions?

*Zach Riggle*