modernc.org/ccgo/v3@v3.16.14/lib/testdata/gcc-9.1.0/gcc/testsuite/gcc.c-torture/compile/20170419-1.c (about)

     1  extern int __fpclassifyd (double x);
     2  
     3  double fdim (double x, double y)
     4  {
     5     int c = __fpclassifyd (x);
     6     if (c == 0)
     7       return (x);
     8     if (__fpclassifyd (y) == 0)
     9       return (y);
    10     if (c == 1)
    11       return (__builtin_huge_val ());
    12     return x > y ? x - y : 0.0;
    13  }