PGO can also record loop sizes, which helps with decisions about vectorization, prefetching, non-temporal stores, etc etc. Call counts are useful for inlining a

PGO can also record loop sizes, which helps with decisions about vectorization, prefetching, non-temporal stores, etc etc. Call counts are useful for inlining and function specialization decisions. I don't know what gcc does, but Open64 does all of the above.