num))
    return false;

  STRIP_NOPS (chrec);
  scev = hide_evolution_in_other_loops_than_loop (chrec, loop_num);
  *res = !tree_contains_chrecs (scev, NULL);
  return true;
}

/* Build a polynomial chain of recurrence.  */

static inline tree
build_polynomial_chrec (unsigned loop_num,
			tree left,
			tree right)
{
  bool val;

  if (left == chrec_dont_know
      || right == chrec_dont_know)
    return chrec_dont_know;

  if (!no_evolution_in_loop_p (left, loop_num, &val)
      || !val)
    return chrec_dont_know;

  /* Types of left and right sides of a chrec should be compatible, but
     pointer CHRECs are special in that the evolution is of ptroff type.  */
  if (POINTER_TYPE_P (TREE_TYPE (left)))
    gcc_checking_assert (ptrofftype_p (TREE_TYPE (right)));
  else
    {
      /* Pointer types should occur only on the left hand side, i.e. in
	 the base of the chrec, and not in the step.  */
      gcc_checking_assert (!POINTER_TYPE_P (TREE_TYPE (right))
			   && types_compatible_p (TREE_TYPE (left),
						  TREE_TYPE (right)));
    }

  if (chrec_zerop (right))
    return left;

  tree chrec = build2 (POLYNOMIAL_CHREC, TREE_TYPE (left), left, right);
  CHREC_VARIABLE (chrec) = loop_num;
  return chrec;
}

/* Determines whether the expression CHREC is a constant.  */

static inline bool
evolution_function_is_constant_p (const_tree chrec)
{
  if (chrec == NULL_TREE)
    return false;

  if (CONSTANT_CLASS_P (chrec))
    return true;
  return is_gimple_min_invariant (chrec);
}

/* Determine whether CHREC is an affine evolution function in LOOPNUM.  */

static inline bool
evolution_function_is_affine_in_loop (const_tree chrec, int loopnum)
{
  if (chrec == NULL_TREE)
    return false;

  switch (TREE_CODE (chrec))
    {
    case POLYNOMIAL_CHREC:
      if (evolution_function_is_invariant_p (CHREC_LEFT (chrec), loopnum)
	  && evolution_function_is_invariant_p (CHREC_RIGHT (chrec), loopnum))
	return true;
      else
	return false;

    default:
      return false;
    }
}

/* Determine whether CHREC is an affine evolution function or not.  */

static inline bool
evolution_function_is_affine_p (const_tree chrec)
{
  return chrec
    && TREE_CODE (chrec) == POLYNOMIAL_CHREC
    && evolution_function_is_invariant_p (CHREC_RIGHT (chrec),
					  CHREC_VARIABLE (chrec))
    && (TREE_CODE (CHREC_RIGHT (chrec)) != POLYNOMIAL_CHREC
	|| evolution_function_is_affine_p (CHREC_RIGHT (chrec)));
}

/* Determines whether EXPR does not contains chrec expressions.  */

static inline bool
tree_does_not_contain_chrecs (const_tree expr)
{
  return !tree_contains_chrecs (expr, NULL);
}

/* Returns the type of the chrec.  */

static inline tree
chrec_type (const_tree chrec)
{
  if (automatically_generated_chrec_p (chrec))
    return NULL_TREE;

  return TREE_TYPE (chrec);
}

static inline tree
chrec_fold_op (enum tree_code code, tree type, tree op0, tree op1)
{
  switch (code)
    {
    case PLUS_EXPR:
      return chrec_fold_plus (type, op0, op1);

    case MINUS_EXPR:
      return chrec_fold_minus (type, op0, op1);

    case MULT_EXPR:
      return chrec_fold_multiply (type, op0, op1);

    default:
      gcc_unreachable ();
    }

}

#endif  /* GCC_TREE_CHREC_H  */