[wolfgke]

> These arguments were constantly going on in the 80s and 90s, where (assembly-enthusiast) people vehemently argued that machines (C compilers) will never optimise things as well as humans.

I still argue this way. But these kinds of optimizations are tedious and time-intensive (thus costly). Also dependent on the architecture, i.e. when some extensions (say new SIMD instructions) are added to the instruction set, the compiler sometimes is able to use them automatically (though typically in a very sub-optimal way), while hand-optimized assembly code has to be rewritten (costly). Also if you port your program to a new CPU architecture (say Intel -> ARM or ARM-A32 -> ARM-A64) hardly anything can be reused. Finally tight hand-optimized code tends to be much harder to add features to than more high-level code (say, C code).

So I believe these vehemently arguing people are right (and have always been). But this does not contradict the fact that in many cases a very suboptimal code generated by the (say C) compiler is often fast enough and C is much more economical to use.