Grab a look at the FDO and AutoFDO sections from GCC's wiki: https://gcc.gnu.org/wiki/AutoFDO/Tutorial https://gcc.gnu.org/wiki/AutoFDO/Tutorial You'll also f

Grab a look at the FDO and AutoFDO sections from GCC's wiki: https://gcc.gnu.org/wiki/AutoFDO/Tutorial https://gcc.gnu.org/wiki/AutoFDO/Tutorial You'll also find it's referred to as Profile Guided Optimization, there's docs here for clang: https://clang.llvm.org/docs/UsersManual.html#profile-guided-optimization https://clang.llvm.org/docs/UsersManual.html#profile-guided-...