On Thu, 26 May 2011, William J. Schmidt wrote: > + /* Optimize pow(x,1./3.) = cbrt(x). This is always safe. */
No, it's not always safe. 1./3. isn't exactly representable; if x is negative (and finite), the correct value of the LHS is a NaN (with the "invalid" exception raised) because the value of 1./3. actually has an even denominator, whereas the correct value of the RHS is a negative real value. -- Joseph S. Myers jos...@codesourcery.com
