It depends on the code - while GCC, being more mature, is typically better at most optimisations, there are a few cases where Clang produces code that is a fair

It depends on the code - while GCC, being more mature, is typically better at most optimisations, there are a few cases where Clang produces code that is a fair bit faster. Over time, as Clang gets more mature, it will become more and more on par (or better) than GCC.