https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82748
--- Comment #1 from Gabriel F. T. Gomes <gabriel at inconstante dot eti.br> --- Some additional information: Replacing __builtin_fabsq (x) with __builtin_copysignq (x, x), in the test program, causes a similar error. Replacing the 'q'-suffixed builtin with its 'f128'-suffixed counterpart makes the error go away.