What I meant is that the assembly instruction is faster only because it does not provide the same level of accuracy as the generic implementation. Everyone's n

What I meant is that the assembly instruction is faster only because it does not provide the same level of accuracy as the generic implementation. Everyone's needs are different, but it does seem that it is a little bit early, and perhaps that it will always be too early, for a general-purpose libm to aim for correctly rounded transcendental function. Even the best implementations only work in one rounding mode, leading to the pleasantries discussed in a sibling of this comment, and the worst-case execution time can be a problem for some. It is possible to aim for 0.51 ULP with implementations that still work(-ish) if the rounding mode is not round-to-nearest, and perhaps this is the sweet spot that libms that want to be useful should aim for.