I’m not totally sure but I think fast math usually comes with loss of support for denormals, which is a bit of range reduction. Note that even if they had denormals, the absolute error listed in the chart is much bigger than the biggest denorm. So you don’t lose range out at the large ends, but you might for very small numbers. Shouldn’t be a problem for sin/cos since the result is never large, but maybe it could be an issue for other ops.