https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91156
--- Comment #1 from emsr at gcc dot gnu.org --- The standard shows the definitions based on the Rodrigues formulae for x >= 0. So maybe this is an extension in the strictest sense. Are the Rodrigues formulae only valid for x >= 0. I don't think so. no. Not for the Laguerre polynomials and the associated Laguerre polynomials. So the x >= 0 should be stricken from the wording on these two functions. (Now for the *Legendre* polynomials and functions, these involve sqrt(1-x^2) so |x| <= 1 is required unless we go off the deep end with complex and watnot. Which we don't really. At least not yet.) Implementors would not have to add new code to support this. Upward recursion works just fine. Summation of a hypergeomeric series would work just fine. in fact, the terms don't alternate so you wouldn't get cancellation errors.
