Why is processing a sorted array faster than an unsorted array?

I've been reading hacker news, daily, for years and this is my first time noticing it. Thanks for posting!

Code in the question is a bad test example. As the answer shows, different compilers can optimize the code in different ways to make the outer loop almost meaningless. A better test would have 100000 different arrays to test.

Did you enable optimizations in C++ and disable adaptive optimization in java?