That C allows developers to play fast and loose is actually one of the reasons why C is slower than Fortran in many cases. Aliasing does not exist in Fortran, and array dimensions are well-defined, and this alone allows for much more aggressive optimizations, impossible to do safely in C.

(Is Fortran still relevant? Try compiling Tensorflow, to say nothing of serious numerical modeling stuff. And yes, I know about __restrict; it's more of a band-aid.)