https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105246
--- Comment #3 from Tobias Burnus <burnus at gcc dot gnu.org> --- (In reply to Andrew Stubbs from comment #2) > Square root. Precision is (2**29) ULP, and supports denormals. > > The compiler already emits Newton Raphson iterations for division with > -ffast-math, so I'm sure it can be done, but I'm not too clear on the > mathematics myself. See for instance https://math.mit.edu/~stevenj/18.335/newton-sqrt.pdf Namely for x = sqrt(a) x_(n+1) = ½ (x_n + a / x_n) This has quadratic convergence.
