A while back I decided to try my hand at including " -flto" in my C{XX}FLAGS and do `emerge -e @world`. Needless to say, by the end of it my "/etc/portage/package.env" was filled with a list of packages that had to disable the flag either because it failed to build or broke other builds. I never reported them as bugs because I always assumed the flag was unsafe and unsupported by Gentoo.
Lately, I have been trying to fix some GCC-6 related bugs and have come across some bug reports that seem possibly more "-flto" related than GCC-6 related. Doing a search for "-flto", Gentoo bugtracker, a number of open bugreports clearly show them to be "-flto" bugs in their titles. Does Gentoo support the "-flto" flag and are "-flto" related bugreports valid?