gas vs. nasm: which assembler produces the best code?

Question

Both tools translate assembly instructions directly into machine code, but is it possible to determine which one produces the fastest and cleanest code?

Answer 1

As a sidenote on the syntax-matter. You can have GAS work perfectly fine with Intel syntax by putting the following line at the top of your source file:

.intel_syntax noprefix

I am using Intel syntax too for all my assmebly needs. It seems far more natural than the AT&T syntax. And it saves some keystrokes :-).