How does C3 compared to C in runtime performance?
I based the LLVM-IR output on what Clang outputs for C. And so they should be identical. C3 has a single module option for maximum interfunctional optimizations, but Clang can give you LTO for the same thing.
So they should be the same, otherwise it's a bug.
C3 is more complex than C (because of a net increase of features), but it's miles from C++ and Rust in complexity and it compiles as fast or faster than C.