https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81616
--- Comment #27 from Jan Hubicka <hubicka at ucw dot cz> --- Hi, one of problem here is use of vgather instruction. It is hardly a win on Zen architecture. It is also on my TODO to adjust the code model to disable it for most loops. I only want to benchmark if it is a win at all in some cases or not at all to set proper weights. You can disable it with -mno-avx2 Still the code is bit worse than for -march=amdfam10 -mtune=k8 which is bit funny. I will take a look at that. Honza