GCC doesn't implement the "dumb approach" that existed before it, and that Amiga and Atari originally had. The GCC approach provides enough information to the

GCC doesn't implement the "dumb approach" that existed before it, and that Amiga and Atari originally had. The GCC approach provides enough information to the compiler that code can be optimized in the presence of inline assembly; the compiler is informed of what the assembler code reads and writes, and can allocate registers for it. It was much more flexible than the implementation in the original Unix compiler.