To be more specific, the linker plugin only performs half of the compilation in a single thread. This is because configure.ac overrides the user-specified flags: -flto=12 -flto-compression-level=0 with these flags: LTOFLAGS="-flto ... -flto-partition=none" I understand that single-threaded lto may produce better optimization, but I don't think it's worth the trade-off. Reproducible: Always
This is more nuanced than it appears, in that the reason we do USE=lto for the configure argument is because for years, the configure test was broken. This has finally been fixed in autoconf-archive via https://github.com/autoconf-archive/autoconf-archive/pull/279, but it's not yet in a release.
