[Bug middle-end/92308] Gimple passes could do a better job of forming address CSEs

[rearnsha at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92308

--- Comment #7 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
Reload also had a hook TARGET_LEGITIMIZE_RELOAD_ADDRESS as well.  But it had
the same problems - lack of context leading to guesswork and therefore too
local or too general fix-ups.