https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113646
--- Comment #4 from Jan Hubicka <hubicka at ucw dot cz> --- > > With -fprofile-partial-training the znver4 LTO vs LTOPGO regression (on a > newer > master) goes down from 66% to 54%. > > So far I did not find a way to easily train with the reference run (when I add > "train_with = refrate" to the config, I always get "ERROR: The workload > specified by train_with MUST be a training workload!") I do that with a crude hack of simply rewriting training data files with reference versions in SPEC directly. I believe that here problem must be that with PGO we confuse vectorizer somehow. I did not know there is train_with option. Perhaps hacking the spec driver to not output error is easy enough
