Downstream, we had a separate set of builds flags for certain packages
and used -O3 there, targeted at POWER (both ppc64 and ppc64le), for
increased use of vectorization presumably.
I don't think this was ever upstreamed to Fedora (the downstream changes
were in the redhat-rpm-config package). I don't recall seeing a
corresponding Fedora change. As a result, the recent downstream rebase
lost support for this.
Should Fedora package maintainers remove _performance_build support or
custom flag overrides for -O3 from their packages?
My understanding is that Fedora build flag policy is set by the
redhat-rpm-config package, which currently specifies -O2 for all
architectures.
Thanks,
Florian