If you take version 4, stop the first while loop once the size is at most 32, and then do linear search from there, it's faster (on my machine). For example, ve

If you take version 4, stop the first while loop once the size is at most 32, and then do linear search from there, it's faster (on my machine). For example, version 4 is 102ms and this tweak puts it at 83ms. (On clang x64.)