If -ffast-math won't work, a few more to consider: -fassociative-math (generally safe unless you're dealing with math written specifically to take advantage of

If -ffast-math won't work, a few more to consider: -fassociative-math (generally safe unless you're dealing with math written specifically to take advantage of the details of floating point arithmetic) -fno-signed-zeros - again, though it's possible some code depends on this, it's rather unlikely. -fno-trapping-math - do you actually use traps?