So far my benchmark scripts are Windows-only so no LTO is available AFAIK. I can work on providing such measures (or any flags you want) on OSX in the future.
I performed an extremely rudimentary -flto=full test on Win64 for a hello-world program yesterday, linking manually via LLD 5.0 (lld-link.exe), which worked (and saved 1 KB for the executable ;)).
