The recent gcc-8 and gcc-9 uploads to unstable are now built using pgo and lto optimization. Not on all architectures, see debian/rules.defs. On the plus side the compilers are 7-10% faster, however the build time of the compiler is much longer, adding 10-20 hours. If people feel that this isn't worth the extra build time, please file an issue for the package to disable those optimizations. Matthias