llvm-gcc-4.2/gcc/testsuite/gcc.c-torture/execute/ieee/fp-cmp-6.c

const double dnan = 1.0/0.0 - 1.0/0.0;
double x = 1.0;

extern void link_error (void);
extern void abort (void);

main ()
{
#if ! defined (__vax__) && ! defined (_CRAY)
  /* NaN is an IEEE unordered operand.  All these test should be false.  */
  if (dnan == dnan)
    link_error ();
  if (dnan != x)
    x = 1.0;
  else
    link_error ();

  if (dnan < x)
    link_error ();
  if (dnan > x)
    link_error ();
  if (dnan <= x)
    link_error ();
  if (dnan >= x)
    link_error ();
  if (dnan == x)
    link_error ();
#endif
  exit (0);
}

#ifndef __OPTIMIZE__
void link_error (void)
{
  abort ();
}
#endif