https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110832
Bug ID: 110832 Summary: 14% capacita -O2 regression between g:9fdbd7d6fa5e0a76 (2023-07-26 01:45) and g:ca912a39cccdd990 (2023-07-27 03:44) on zen3 and core Product: gcc Version: 13.1.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: middle-end Assignee: unassigned at gcc dot gnu.org Reporter: hubicka at gcc dot gnu.org Target Milestone: --- Biggest regression is seen here https://lnt.opensuse.org/db_default/v4/CPP/graph?plot.0=466.758.0 zen3 https://lnt.opensuse.org/db_default/v4/CPP/graph?plot.0=466.758.0 Curiously zen2 improves: https://lnt.opensuse.org/db_default/v4/CPP/graph?plot.0=171.758.0 I can see instruction count differnece in perfs: Performance counter stats for './a.out': 10923.70 msec task-clock:u # 1.000 CPUs utilized 0 context-switches:u # 0.000 /sec 0 cpu-migrations:u # 0.000 /sec 15510 page-faults:u # 1.420 K/sec 59062937176 cycles:u # 5.407 GHz (83.33%) 12607081 stalled-cycles-frontend:u # 0.02% frontend cycles idle (83.34%) 122404896 stalled-cycles-backend:u # 0.21% backend cycles idle (83.34%) 112648123380 instructions:u # 1.91 insn per cycle # 0.00 stalled cycles per insn (83.34%) 9666338531 branches:u # 884.896 M/sec (83.34%) 2937216 branch-misses:u # 0.03% of all branches (83.31%) 10.924108973 seconds time elapsed 10.912056000 seconds user 0.012000000 seconds sys Performance counter stats for './b.out': 11025.38 msec task-clock:u # 1.000 CPUs utilized 0 context-switches:u # 0.000 /sec 0 cpu-migrations:u # 0.000 /sec 14998 page-faults:u # 1.360 K/sec 59436352848 cycles:u # 5.391 GHz (83.31%) 9217660 stalled-cycles-frontend:u # 0.02% frontend cycles idle (83.32%) 210162784 stalled-cycles-backend:u # 0.35% backend cycles idle (83.35%) 131604240004 instructions:u # 2.21 insn per cycle # 0.00 stalled cycles per insn (83.35%) 9657712171 branches:u # 875.953 M/sec (83.35%) 3146487 branch-misses:u # 0.03% of all branches (83.33%) 11.025701172 seconds time elapsed 11.005646000 seconds user 0.020002000 seconds sys however perf report does not show clear differences in times of functions. I