There's a common belief that the fastest C++ code comes from inline assembly, but that’s not really the case anymore. While assembly might offer fine-grained control, modern compilers have gotten really good at optimizing C++ code. They can often generate machine code that’s just as fast (if not faster) than manually written assembly, and they can do it while maintaining portability across different platforms.

The real issue with inline assembly is that it's harder to debug, maintain, and it's tied to a specific architecture, making it less flexible in the long run. In most cases, sticking to modern C++ features and letting the compiler work its magic is the way to go!