[Bug libquadmath/63488] large errors in y0q

[fxcoudert at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63488

--- Comment #2 from Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> ---
The code in question is at libquadmath/math/j0q.c, function y0q, in the branch
annotated  /* 0 <= x <= 2 */

It has to do with the rational function:

/* Y0(x) = 2/pi * log(x) * J0(x) + R(x^2)
   Peak absolute error 1.7e-36 (relative where Y0 > 1)
   0 <= x <= 2   */

Coefficients are in Y0_2N and Y0_2D.

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It would be useful to confirm this bug in the upstream glibc's j0l(), as it
probably manifests on 128-bit long double
(glibc/sysdeps/ieee754/ldbl-128/e_j0l.c).