The wide gap between those two options is kind of dissatisfying, it would be cool if LTO could disassemble existing object files and do the unused code removal on the assembly language layer. I guess that Facebook BOLT and Google Propeller are working on an approach like that.

https://github.com/facebookincubator/BOLT https://www.phoronix.com/scan.php?page=news_item&px=Google-P...