"Frank W. Miller" <fwmiller@xxxxxxxxxxx> writes: > Another question, if I want to optimize for core 2 duo, what -mtune should I > use? -mtune=core2. But it's not supported in gcc 4.2.x. It will be supported in gcc 4.3.0 when it comes out. In 4.2 it's probably best to use -mtune=generic, which is the default anyhow. Ian