Eli Zaretskii <eliz@gnu.org> writes:

> I'm still unconvinced, and I said already what will have a chance of
> convincing me: a specific report about a problem this particular code
> causes on a specific existing platform we support in Emacs 29 and with
> a specific compiler.

Similar (but not exactly the same) loops as this one have been shown to
generate incorrect code in this thread.  It's not a large leap for it to
happen to this one, introducing subtle errors for a bit of code that is
completely unnecessary (as demonstrated by it being optional),
especially at higher optimization levels, where the compiler could
easily produce better code than the assumption of a 'mov' would.

Is the following trivial enough for 29?