https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101891
Arjan van de Ven <arjan at linux dot intel.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |arjan at linux dot intel.com --- Comment #7 from Arjan van de Ven <arjan at linux dot intel.com> --- from a performance angle, the xor-only sequence is not so great at all; modern CPUs are really good at eliminating mov's so that's why the code originally was added to do a combo of xor and mov.. I can understand the security versus performance tradeoff. (the original tuning was done to basically make it entirely free, so that it could just be always enabled)