gcc/testsuite/gcc.c-torture/execute/ieee/unsafe-fp-assoc-1.c

   1 extern void abort();
   2
   3 typedef union {
   4        struct {
   5   unsigned int hi;
   6   unsigned int lo;
   7  } i;
   8        double d;
   9 } hexdouble;
  10
  11 static const double twoTo52 = 0x1.0p+52;
  12
  13 void func ( double x )
  14 {
  15       hexdouble argument;
  16       register double y, z;
  17       unsigned int xHead;
  18       argument.d = x;
  19       xHead = argument.i.hi & 0x7fffffff;
  20       if (__builtin_expect(!!(xHead < 0x43300000u), 1))
  21        {
  22                   y = ( x - twoTo52 ) + twoTo52;
  23                   if ( y != x )
  24                     abort();
  25                   z = x - 0.5;
  26                   y = ( z - twoTo52 ) + twoTo52;
  27                   if ( y == (( x - twoTo52 ) + twoTo52) )
  28                     abort();
  29        }
  30      return;
  31 }
  32
  33 int main()
  34 {
  35         if (sizeof (double) == 4)
  36                 return 0;
  37         func((double)1.00);
  38         return 0;
  39 }