modernc.org/ccgo/v3@v3.16.14/lib/testdata/gcc-9.1.0/gcc/testsuite/gcc.c-torture/execute/pr35456.c (about)

     1  /* { dg-skip-if "signed zero not supported" { "vax-*-*" } } */
     2  extern void abort (void);
     3  
     4  double
     5  __attribute__ ((noinline))
     6  not_fabs (double x)
     7  {
     8    return x >= 0.0 ? x : -x;
     9  }
    10  
    11  int main()
    12  {
    13    double x = -0.0;
    14    double y;
    15  
    16    y = not_fabs (x);
    17  
    18    if (!__builtin_signbit (y))
    19      abort();
    20  
    21    return 0;
    22  }