https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90056
Martin Jambor <jamborm at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |MOVED --- Comment #2 from Martin Jambor <jamborm at gcc dot gnu.org> --- (In reply to Martin Jambor from comment #0) > As of revision 270053, the 548.exchange2_r benchmark from SPEC 2017 > INTrate suite suffered a number of smaller regressions on AMD Zen > CPUs: > > - At -O2, it is 4.5% slower than when compiled with GCC 7 I am about to file a specific bug about exchange at -O2. > - At -Ofast, it is 4.7% slower than when compiled with GCC 8 This is no longer true. > - At -Ofast -march=native -mutine=native, this difference is 6.9% Again, I will file a more specific bug about -Ofast -march=native in a little while. > - At -Ofast and native tuning, it is 6% slower with PGO than > without it. I can still see this in my measurements on Zen1-based CPU but not in those done on AMD Zen2 or Intel Cascade Lake. So I am not sure if we care. I'll e happy to file a specific bug if we do.