If you compile any C program with a C++ compiler (possibly making trivial changes to account for gratuitous language divergence) you will find, for reasons you note yourself, that it runs at exactly the same speed. NOT, let me emphasize here because this seems to be difficult to process, ever slower than C. Therefore, (try to follow this) C is never faster than C++.
So, it is at best foolish to insist that C can ever be faster than C. The falsehood is trivially exposed.
If you think that C++ is about OO gook and virtual functions, an education awaits. But not here.
You don't need a benchmark. Given any C code, you can make a C++ code that runs as fast (just use the same code). This proves that C++ is at least as fast as C.
From there, maybe you could use C++ features to improve the speed (and then C++ is faster) or you could not (and then they have the same speed).
If you compile any C program with a C++ compiler (possibly making trivial changes to account for gratuitous language divergence) you will find, for reasons you note yourself, that it runs at exactly the same speed. NOT, let me emphasize here because this seems to be difficult to process, ever slower than C. Therefore, (try to follow this) C is never faster than C++.
So, it is at best foolish to insist that C can ever be faster than C. The falsehood is trivially exposed.
If you think that C++ is about OO gook and virtual functions, an education awaits. But not here.