http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21718
--- Comment #19 from Rick Regan <exploringbinary at gmail dot com> --- I've looked into this and found that real.c/real.h use a precision of SIGNIFICAND_BITS, which is dependent on an architecture-dependent value called HOST_BITS_PER_LONG. In addition, SIGNIFICAND_BITS limits the precision to 192 bits on a 64-bit system, and I was able to find an example of an incorrect conversion there: 5.0216813883093451685872615018317116712748411717802652598273e58. (Please see my article http://www.exploringbinary.com/gcc-conversions-are-incorrect-architecture-or-otherwise/ for details.)
