[Bug ipa/96337] [10/11 Regression] GCC 10.2: twice as slow for -O2 -march=x86-64 vs. GCC 9.3/8.4

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96337

--- Comment #6 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
Coremark.

GCC 9 run1:
CoreMark Size    : 666
Total ticks      : 12310
Total time (secs): 12.310000
Iterations/Sec   : 24370.430544
Iterations       : 300000
Compiler version : GCC9.3.1 20200406 [revision
6db837a5288ee3ca5ec504fbd5a765817e556ac2]
Compiler flags   : -O2 -DPERFORMANCE_RUN=1  -lrt

GCC 9 run2:
CoreMark Size    : 666
Total ticks      : 12471
Total time (secs): 12.471000
Iterations/Sec   : 24055.809478
Iterations       : 300000
Compiler version : GCC9.3.1 20200406 [revision
6db837a5288ee3ca5ec504fbd5a765817e556ac2]
Compiler flags   : -O2 -DPERFORMANCE_RUN=1  -lrt


GCC 10 run1:
CoreMark Size    : 666
Total ticks      : 15269
Total time (secs): 15.269000
Iterations/Sec   : 26196.869474
Iterations       : 400000
Compiler version : GCC10.1.1 20200507 [revision
dd38686d9c810cecbaa80bb82ed91caaa58ad635]
Compiler flags   : -O2 -DPERFORMANCE_RUN=1  -lrt

GCC 10 run2:
CoreMark Size    : 666
Total ticks      : 11770
Total time (secs): 11.770000
Iterations/Sec   : 25488.530161
Iterations       : 300000
Compiler version : GCC10.1.1 20200507 [revision
dd38686d9c810cecbaa80bb82ed91caaa58ad635]
Compiler flags   : -O2 -DPERFORMANCE_RUN=1  -lrt