https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89540
--- Comment #1 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- Are you sure you're using (at runtime) the libquadmath from the GCC version you're using (via -rpath / LD_LIBRARY_PATH, or linking with static rather than shared libquadmath), rather than an older shared library from your distribution? This looks very much like bug 65757, which was fixed some time ago (for GCC 8 and backported to older release branches).
