And the downvote brigade arrives, consisting entirely of programmers who don't read the assembly outputted by their compiler. Part of the problem is simply tha

And the downvote brigade arrives, consisting entirely of programmers who don't read the assembly outputted by their compiler. Part of the problem is simply that compilers typically cannot know the same information the programmer knows: assumptions about alignment and aliasing, for example, that the programmer knows, but the compiler doesn't. But even if they did, there are plenty of cases where "producing good assembly code for a given algorithm" is infeasible with a brute-force approach, requiring the imprecise-but-effective pattern-matching of a human brain -- or something similarly powerful.