I am working on a project with a lot of vector math and I'd like to find a way to speed it up. I've been reading about SSE, but I've found no explanation on how to actually use it in code (was looking for some kind of hello-world example, complete with compilation instructions).

Does the gcc compiler automatically make use of SSE, if you add the -sse(2,3) option on the command line? Or are their specific functions/libraries you need to call?