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[/] [openrisc/] [trunk/] [gnu-stable/] [gcc-4.5.1/] [gcc/] [testsuite/] [gcc.target/] [spu/] [dfcgt-nan.c] - Rev 859

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/* { dg-do compile } */
/* { dg-options "-march=celledp -O1" } */
/* { dg-final { scan-assembler "dfceq" } } */
 
/* GCC previously transformed an "a <= b" test into "! (a > b)" when
   compiling with -march=celledp, so that the dfcgt instruction can be
   used to implement the comparison.
 
   However, this transformation violates the IEEE-754 standard in the
   presence of NaN values.  If either a or b is a NaN, a <= b should
   evaluate to false according to IEEE rules.  However, after the
   transformation, a > b as implemented by dfcgt itself returns false,
   so the transformed test returns true.
 
   Note that the equivalent transformation is valid for single-
   precision floating-point values on the Cell SPU, because the format
   does not have NaNs.  It is invalid for double-precision, even on
   Cell, however.  */
 
int test (double a, double b) __attribute__ ((noinline));
int test (double a, double b)
{
  return a <= b;
}
 
int main (void)
{
  double x = 0.0;
  double y = 0.0/0.0;
  return test (x, y);
}
 

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