I am not sure I can buy such a comparison.
Someone smarter than me already argued about test implementations.
Someone else also put compilers and interpreters into prospective.
Of course language expressiveness can gauge in but, IMHO, comparing the same sort algorithm or the same hash table implementation (or n-queens algo) could make much more sense especially with comparable compilers.
If Rust implementation is father than C's, kudos goes to the compiler, not to the language
The Rust language specifically gives more information and thus more optimization opportunities to the compiler. Plus, when comparing Rust code compiled with rustc and C code compiled with Clang, both are using LLVM as the compiler backend, so what primarily comes into play is how expressive each language is, and how idiomatic it is to write code that will be optimized by the compiler.
Both C and Rust are capable of just inlining optimal assembly, so comparing "pure speed potential" is pointless.
OK. So you say that implementations are the same within the respective language capabilities and that the Rust compiler frontend is inherently better than C's thanks to the language expressiveness?
Still sounds weird to me, unless the test programs use very different approaches, like parallel programming...
If Rust implementation is father than C's, kudos goes to the compiler, not to the language