[eru]

Though the main reason (for a while) that Fortran compilers could produce faster code was that they were allowed to assume that variables (including arguments to your functions) don't alias each other.

See http://beza1e1.tuxen.de/articles/faster_than_C.html

[Ragib_Zaman]

I don't understand the "Though" part of this. The only reason any compiled language may be faster than another is because a compiler knows/assumes more about the code (either through users specification, or restrictions of the language).

[eru]

Yes. That's the remaining reason when compilers for the languages in question have gotten as good as they can get.