It’s not compiling C code, so that’s not really possible to answer. C is uniquely fast to compile, especially compared with more featureful languages like C++ and Rust.

In practice, C++ and Rust feel pretty similar, mostly due to the kind of code people tend to write in both languages (favoring static dispatch, generics/templates, etc.).

Rephrased question: How does the Rust compiler's speed compare to the C compiler GCC's speed with respect the language each is compiling, i.e., rust and C, respectively