https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83665
--- Comment #2 from Jan Hubicka <hubicka at gcc dot gnu.org> --- One potential candidate is the ipa-inline big_speedup_p fix by Richard. It does not seem to explain all the difference though. I have quickly checked that it does affect gzip LTO binary, but less than reported - by about 2.5KB.
