My experience is actually that C is extremely difficult to optimize It s only been optimized as much as it has due to a great deal of focused research on procedural programs in particular which is largely because of C s predominance Early compilers certainly struggled to optimize even simple C programs due to complex issues of potential aliasing due to pointers variables with long live ranges and so on I think if we re going to construct a discussion of why C programs are often more efficient than similar programs written in other languages it should focus primarily on the level of detailed control given to the programmer the efficiency of its primitive operations the lack of overhead from a runtime infrastructure and so on