------- Comment #1 from burnus at gcc dot gnu dot org 2007-12-04 10:26 ------- http://www.mpfr.org/mpfr-2.3.0/mpfr.html#Comparison-Functions
Function: int mpfr_cmp (mpfr_t op1, mpfr_t op2) "If one of the operands is NaN, set the erange flag and return zero. Note: These functions may be useful to distinguish the three possible cases. If you need to distinguish two cases only, it is recommended to use the predicate functions (e.g., mpfr_equal_p for the equality) described below; they behave like the IEEE-754 comparisons, in particular when one or both arguments are NaN. But only floating-point numbers can be compared (you may need to do a conversion first)." -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34333
