[Bug target/82267] x32: unnecessary address-size prefixes. Why isn't -maddress-mode=long the default?

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82267

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
> Is it really necessary for an unsigned offset to be wrap at 4G?  Does ISO C or GNU C guarantee that large unsigned values work like negative signed integers when used for pointer arithmetic?

I think it does not guarantee that.  But on RTL we've lost signedness and we
probably cannot distinguish this from the case of a negative value so we have
to sign-extend.