In University computer architecture courses, we were challenged to write a quicksort routine in assembly. We were also asked to compare the assembly that we authored with assembly that was compiled from C++ (after we authored our own solutions, of course).
It was an amazing crash-course on just how good compilers have become at optimizing. Not a single student could hand craft assembly that was faster than the compiler output. The teacher of the course was able to generate assembly that was slightly faster, and he stated that in order to do so, he had to greatly exploit his in-depth knowledge of the processor's pipeline system. That was roughly year 2000, and I'm sure compilers have only become better at their job since then.
All in all, excellent learning experience. I've since encountered several instances where developers assert superior assembly skills, and by default I'm silently skeptical of their claims.
Gathering and exploiting in-depth knowledge of a CPU's internals has become more difficult over time, too, I think.
At least for x86/amd64 - with out-of-order-exection, branch prediction and whatnot one not only has to know the architecture, but one has to know the specific implementation the code will run on. And knowledge on the deep internals of CPUs made by Intel or AMD (or Via? are they still around?) is not easy to come by.
It was an amazing crash-course on just how good compilers have become at optimizing. Not a single student could hand craft assembly that was faster than the compiler output. The teacher of the course was able to generate assembly that was slightly faster, and he stated that in order to do so, he had to greatly exploit his in-depth knowledge of the processor's pipeline system. That was roughly year 2000, and I'm sure compilers have only become better at their job since then.
All in all, excellent learning experience. I've since encountered several instances where developers assert superior assembly skills, and by default I'm silently skeptical of their claims.