https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119694
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
getenv is also not the cheapest thing to do, so I'd at least put it behind a
debug option (or param?).
So for now, amend the existing -f{flex,trace,yacc}-debug flags with
a -fextra-debug flag and replace the getenv("") calls with
flag_extra_debug && getenv("")?
