BTW if you are interested in the final result you do need to initialize your uuids with some random values. VC initializes all bytes with zeros and is smart enough to remember that id1 does not change: Ok. I just cannot help it. I have corrected the ids declarations myself the following way int main() { boost::uuids::uuid id1((boost::uuids::random_generator()())), id2((boost::uuids::random_generator()())); ...
and my results are as following: Eq16 -- 100% my_memcmp -- 138.89 % memcmp -- 169.17 % operator == -- 199.72 % Eq16 became even faster. This is most likely due to the fact the first comparison became to fire much more often. Anyway with proper alignment (and I am dead sure every compiler that is sensitive to the alignment has a proper tweakster for it) Eq16 (it shall read Eq32 indeed) shall be the fastest way to compare uint8_t[16] array. Unless you are going to implement Eq64 for x64 platforms... BTW, for unoptimized (Debug) mode: Eq16 (optimized) -- 100 % operator == (optimized) -- 199.72 % Eq16 (unoptimized) -- 247.5 % operator == (unoptimized) -- 1419.16 % No comments. -- Michael Kochetkov