C++ CHREC_LEFT函数代码示例

bool
evolution_function_is_affine_multivariate_p (const_tree chrec, int loopnum)
{
  if (chrec == NULL_TREE)
    return false;

  switch (TREE_CODE (chrec))
    {
    case POLYNOMIAL_CHREC:
      if (evolution_function_is_invariant_rec_p (CHREC_LEFT (chrec), loopnum))
	{
	  if (evolution_function_is_invariant_rec_p (CHREC_RIGHT (chrec), loopnum))
	    return true;
	  else
	    {
	      if (TREE_CODE (CHREC_RIGHT (chrec)) == POLYNOMIAL_CHREC
		  && CHREC_VARIABLE (CHREC_RIGHT (chrec))
		     != CHREC_VARIABLE (chrec)
		  && evolution_function_is_affine_multivariate_p
		  (CHREC_RIGHT (chrec), loopnum))
		return true;
	      else
		return false;
	    }
	}
      else
	{
	  if (evolution_function_is_invariant_rec_p (CHREC_RIGHT (chrec), loopnum)
	      && TREE_CODE (CHREC_LEFT (chrec)) == POLYNOMIAL_CHREC
	      && CHREC_VARIABLE (CHREC_LEFT (chrec)) != CHREC_VARIABLE (chrec)
	      && evolution_function_is_affine_multivariate_p
	      (CHREC_LEFT (chrec), loopnum))
	    return true;
	  else
	    return false;
	}

    default:
      return false;
    }
}

static inline tree
chrec_fold_multiply_poly_poly (tree type,
			       tree poly0,
			       tree poly1)
{
  tree t0, t1, t2;
  int var;
  struct loop *loop0 = get_chrec_loop (poly0);
  struct loop *loop1 = get_chrec_loop (poly1);

  gcc_assert (poly0);
  gcc_assert (poly1);
  gcc_assert (TREE_CODE (poly0) == POLYNOMIAL_CHREC);
  gcc_assert (TREE_CODE (poly1) == POLYNOMIAL_CHREC);
  gcc_checking_assert (useless_type_conversion_p (type, chrec_type (poly0))
		       && useless_type_conversion_p (type, chrec_type (poly1)));

  /* {a, +, b}_1 * {c, +, d}_2  ->  {c*{a, +, b}_1, +, d}_2,
     {a, +, b}_2 * {c, +, d}_1  ->  {a*{c, +, d}_1, +, b}_2,
     {a, +, b}_x * {c, +, d}_x  ->  {a*c, +, a*d + b*c + b*d, +, 2*b*d}_x.  */
  if (flow_loop_nested_p (loop0, loop1))
    /* poly0 is a constant wrt. poly1.  */
    return build_polynomial_chrec
      (CHREC_VARIABLE (poly1),
       chrec_fold_multiply (type, CHREC_LEFT (poly1), poly0),
       CHREC_RIGHT (poly1));

  if (flow_loop_nested_p (loop1, loop0))
    /* poly1 is a constant wrt. poly0.  */
    return build_polynomial_chrec
      (CHREC_VARIABLE (poly0),
       chrec_fold_multiply (type, CHREC_LEFT (poly0), poly1),
       CHREC_RIGHT (poly0));

  gcc_assert (loop0 == loop1);

  /* poly0 and poly1 are two polynomials in the same variable,
     {a, +, b}_x * {c, +, d}_x  ->  {a*c, +, a*d + b*c + b*d, +, 2*b*d}_x.  */

  /* "a*c".  */
  t0 = chrec_fold_multiply (type, CHREC_LEFT (poly0), CHREC_LEFT (poly1));

  /* "a*d + b*c".  */
  t1 = chrec_fold_multiply (type, CHREC_LEFT (poly0), CHREC_RIGHT (poly1));
  t1 = chrec_fold_plus (type, t1, chrec_fold_multiply (type,
						       CHREC_RIGHT (poly0),
						       CHREC_LEFT (poly1)));
  /* "b*d".  */
  t2 = chrec_fold_multiply (type, CHREC_RIGHT (poly0), CHREC_RIGHT (poly1));
  /* "a*d + b*c + b*d".  */
  t1 = chrec_fold_plus (type, t1, t2);
  /* "2*b*d".  */
  t2 = chrec_fold_multiply (type, SCALAR_FLOAT_TYPE_P (type)
			    ? build_real (type, dconst2)
			    : build_int_cst (type, 2), t2);

  var = CHREC_VARIABLE (poly0);
  return build_polynomial_chrec (var, t0,
				 build_polynomial_chrec (var, t1, t2));
}

bool
evolution_function_is_univariate_p (const_tree chrec)
{
  if (chrec == NULL_TREE)
    return true;
  
  switch (TREE_CODE (chrec))
    {
    case POLYNOMIAL_CHREC:
      switch (TREE_CODE (CHREC_LEFT (chrec)))
	{
	case POLYNOMIAL_CHREC:
	  if (CHREC_VARIABLE (chrec) != CHREC_VARIABLE (CHREC_LEFT (chrec)))
	    return false;
	  if (!evolution_function_is_univariate_p (CHREC_LEFT (chrec)))
	    return false;
	  break;
	  
	default:
	  break;
	}
      
      switch (TREE_CODE (CHREC_RIGHT (chrec)))
	{
	case POLYNOMIAL_CHREC:
	  if (CHREC_VARIABLE (chrec) != CHREC_VARIABLE (CHREC_RIGHT (chrec)))
	    return false;
	  if (!evolution_function_is_univariate_p (CHREC_RIGHT (chrec)))
	    return false;
	  break;
	  
	default:
	  break;	  
	}
      
    default:
      return true;
    }
}

bool
eq_evolutions_p (const_tree chrec0, const_tree chrec1)
{
  if (chrec0 == NULL_TREE
      || chrec1 == NULL_TREE
      || TREE_CODE (chrec0) != TREE_CODE (chrec1))
    return false;

  if (chrec0 == chrec1)
    return true;

  if (! types_compatible_p (TREE_TYPE (chrec0), TREE_TYPE (chrec1)))
    return false;

  switch (TREE_CODE (chrec0))
    {
    case POLYNOMIAL_CHREC:
      return (CHREC_VARIABLE (chrec0) == CHREC_VARIABLE (chrec1)
	      && eq_evolutions_p (CHREC_LEFT (chrec0), CHREC_LEFT (chrec1))
	      && eq_evolutions_p (CHREC_RIGHT (chrec0), CHREC_RIGHT (chrec1)));

    case PLUS_EXPR:
    case MULT_EXPR:
    case MINUS_EXPR:
    case POINTER_PLUS_EXPR:
      return eq_evolutions_p (TREE_OPERAND (chrec0, 0),
			      TREE_OPERAND (chrec1, 0))
	  && eq_evolutions_p (TREE_OPERAND (chrec0, 1),
			      TREE_OPERAND (chrec1, 1));

    CASE_CONVERT:
      return eq_evolutions_p (TREE_OPERAND (chrec0, 0),
			      TREE_OPERAND (chrec1, 0));

    default:
      return operand_equal_p (chrec0, chrec1, 0);
    }
}

tree 
reset_evolution_in_loop (unsigned loop_num,
			 tree chrec, 
			 tree new_evol)
{
  if (TREE_CODE (chrec) == POLYNOMIAL_CHREC
      && CHREC_VARIABLE (chrec) > loop_num)
    {
      tree left = reset_evolution_in_loop (loop_num, CHREC_LEFT (chrec),
					   new_evol);
      tree right = reset_evolution_in_loop (loop_num, CHREC_RIGHT (chrec),
					    new_evol);
      return build3 (POLYNOMIAL_CHREC, TREE_TYPE (left),
		     build_int_cst (NULL_TREE, CHREC_VARIABLE (chrec)),
		     left, right);
    }

  while (TREE_CODE (chrec) == POLYNOMIAL_CHREC
	 && CHREC_VARIABLE (chrec) == loop_num)
    chrec = CHREC_LEFT (chrec);
  
  return build_polynomial_chrec (loop_num, chrec, new_evol);
}

static bool
graphite_can_represent_scev (tree scev)
{
  if (chrec_contains_undetermined (scev))
    return false;

  switch (TREE_CODE (scev))
    {
    case NEGATE_EXPR:
    case BIT_NOT_EXPR:
    CASE_CONVERT:
    case NON_LVALUE_EXPR:
      return graphite_can_represent_scev (TREE_OPERAND (scev, 0));

    case PLUS_EXPR:
    case POINTER_PLUS_EXPR:
    case MINUS_EXPR:
      return graphite_can_represent_scev (TREE_OPERAND (scev, 0))
	&& graphite_can_represent_scev (TREE_OPERAND (scev, 1));

    case MULT_EXPR:
      return !CONVERT_EXPR_CODE_P (TREE_CODE (TREE_OPERAND (scev, 0)))
	&& !CONVERT_EXPR_CODE_P (TREE_CODE (TREE_OPERAND (scev, 1)))
	&& !(chrec_contains_symbols (TREE_OPERAND (scev, 0))
	     && chrec_contains_symbols (TREE_OPERAND (scev, 1)))
	&& graphite_can_represent_init (scev)
	&& graphite_can_represent_scev (TREE_OPERAND (scev, 0))
	&& graphite_can_represent_scev (TREE_OPERAND (scev, 1));

    case POLYNOMIAL_CHREC:
      /* Check for constant strides.  With a non constant stride of
	 'n' we would have a value of 'iv * n'.  Also check that the
	 initial value can represented: for example 'n * m' cannot be
	 represented.  */
      if (!evolution_function_right_is_integer_cst (scev)
	  || !graphite_can_represent_init (scev))
	return false;
      return graphite_can_represent_scev (CHREC_LEFT (scev));

    default:
      break;
    }

  /* Only affine functions can be represented.  */
  if (tree_contains_chrecs (scev, NULL)
      || !scev_is_linear_expression (scev))
    return false;

  return true;
}

bool
is_multivariate_chrec (const_tree chrec)
{
  if (chrec == NULL_TREE)
    return false;

  if (TREE_CODE (chrec) == POLYNOMIAL_CHREC)
    return (is_multivariate_chrec_rec (CHREC_LEFT (chrec),
				       CHREC_VARIABLE (chrec))
	    || is_multivariate_chrec_rec (CHREC_RIGHT (chrec),
					  CHREC_VARIABLE (chrec)));
  else
    return false;
}

bool
evolution_function_right_is_integer_cst (const_tree chrec)
{
  if (chrec == NULL_TREE)
    return false;

  switch (TREE_CODE (chrec))
    {
    case INTEGER_CST:
      return true;

    case POLYNOMIAL_CHREC:
      return TREE_CODE (CHREC_RIGHT (chrec)) == INTEGER_CST
	&& (TREE_CODE (CHREC_LEFT (chrec)) != POLYNOMIAL_CHREC
	    || evolution_function_right_is_integer_cst (CHREC_LEFT (chrec)));

    CASE_CONVERT:
      return evolution_function_right_is_integer_cst (TREE_OPERAND (chrec, 0));

    default:
      return false;
    }
}

tree 
chrec_convert (tree type, 
	       tree chrec)
{
  tree ct;
  
  if (automatically_generated_chrec_p (chrec))
    return chrec;
  
  ct = chrec_type (chrec);
  if (ct == type)
    return chrec;

  if (TYPE_PRECISION (ct) < TYPE_PRECISION (type))
    return count_ev_in_wider_type (type, chrec);

  switch (TREE_CODE (chrec))
    {
    case POLYNOMIAL_CHREC:
      return build_polynomial_chrec (CHREC_VARIABLE (chrec),
				     chrec_convert (type,
						    CHREC_LEFT (chrec)),
				     chrec_convert (type,
						    CHREC_RIGHT (chrec)));

    default:
      {
	tree res = fold_convert (type, chrec);

	/* Don't propagate overflows.  */
	TREE_OVERFLOW (res) = 0;
	if (CONSTANT_CLASS_P (res))
	  TREE_CONSTANT_OVERFLOW (res) = 0;

	/* But reject constants that don't fit in their type after conversion.
	   This can happen if TYPE_MIN_VALUE or TYPE_MAX_VALUE are not the
	   natural values associated with TYPE_PRECISION and TYPE_UNSIGNED,
	   and can cause problems later when computing niters of loops.  Note
	   that we don't do the check before converting because we don't want
	   to reject conversions of negative chrecs to unsigned types.  */
	if (TREE_CODE (res) == INTEGER_CST
	    && TREE_CODE (type) == INTEGER_TYPE
	    && !int_fits_type_p (res, type))
	  res = chrec_dont_know;

	return res;
      }
    }
}

bool 
eq_evolutions_p (const_tree chrec0, const_tree chrec1)
{
  if (chrec0 == NULL_TREE
      || chrec1 == NULL_TREE
      || TREE_CODE (chrec0) != TREE_CODE (chrec1))
    return false;

  if (chrec0 == chrec1)
    return true;

  switch (TREE_CODE (chrec0))
    {
    case INTEGER_CST:
      return operand_equal_p (chrec0, chrec1, 0);

    case POLYNOMIAL_CHREC:
      return (CHREC_VARIABLE (chrec0) == CHREC_VARIABLE (chrec1)
	      && eq_evolutions_p (CHREC_LEFT (chrec0), CHREC_LEFT (chrec1))
	      && eq_evolutions_p (CHREC_RIGHT (chrec0), CHREC_RIGHT (chrec1)));
    default:
      return false;
    }  
}

static inline tree
chrec_fold_poly_cst (enum tree_code code,
		     tree type,
		     tree poly,
		     tree cst)
{
  gcc_assert (poly);
  gcc_assert (cst);
  gcc_assert (TREE_CODE (poly) == POLYNOMIAL_CHREC);
  gcc_checking_assert (!is_not_constant_evolution (cst));
  gcc_checking_assert (useless_type_conversion_p (type, chrec_type (poly)));

  switch (code)
    {
    case PLUS_EXPR:
      return build_polynomial_chrec
	(CHREC_VARIABLE (poly),
	 chrec_fold_plus (type, CHREC_LEFT (poly), cst),
	 CHREC_RIGHT (poly));

    case MINUS_EXPR:
      return build_polynomial_chrec
	(CHREC_VARIABLE (poly),
	 chrec_fold_minus (type, CHREC_LEFT (poly), cst),
	 CHREC_RIGHT (poly));

    case MULT_EXPR:
      return build_polynomial_chrec
	(CHREC_VARIABLE (poly),
	 chrec_fold_multiply (type, CHREC_LEFT (poly), cst),
	 chrec_fold_multiply (type, CHREC_RIGHT (poly), cst));

    default:
      return chrec_dont_know;
    }
}

static bool
is_multivariate_chrec_rec (const_tree chrec, unsigned int rec_var)
{
  if (chrec == NULL_TREE)
    return false;

  if (TREE_CODE (chrec) == POLYNOMIAL_CHREC)
    {
      if (CHREC_VARIABLE (chrec) != rec_var)
	return true;
      else
	return (is_multivariate_chrec_rec (CHREC_LEFT (chrec), rec_var)
		|| is_multivariate_chrec_rec (CHREC_RIGHT (chrec), rec_var));
    }
  else
    return false;
}

tree 
chrec_replace_initial_condition (tree chrec, 
				 tree init_cond)
{
  if (automatically_generated_chrec_p (chrec))
    return chrec;
  
  switch (TREE_CODE (chrec))
    {
    case POLYNOMIAL_CHREC:
      return build_polynomial_chrec 
	(CHREC_VARIABLE (chrec),
	 chrec_replace_initial_condition (CHREC_LEFT (chrec), init_cond),
	 CHREC_RIGHT (chrec));
      
    default:
      return init_cond;
    }
}

static bool
evolution_function_is_invariant_rec_p (tree chrec, int loopnum)
{
  if (evolution_function_is_constant_p (chrec))
    return true;

  if (TREE_CODE (chrec) == SSA_NAME
      && (loopnum == 0
	  || expr_invariant_in_loop_p (get_loop (cfun, loopnum), chrec)))
    return true;

  if (TREE_CODE (chrec) == POLYNOMIAL_CHREC)
    {
      if (CHREC_VARIABLE (chrec) == (unsigned) loopnum
	  || flow_loop_nested_p (get_loop (cfun, loopnum),
				 get_chrec_loop (chrec))
	  || !evolution_function_is_invariant_rec_p (CHREC_RIGHT (chrec),
						     loopnum)
	  || !evolution_function_is_invariant_rec_p (CHREC_LEFT (chrec),
						     loopnum))
	return false;
      return true;
    }

  switch (TREE_OPERAND_LENGTH (chrec))
    {
    case 2:
      if (!evolution_function_is_invariant_rec_p (TREE_OPERAND (chrec, 1),
						  loopnum))
	return false;

    case 1:
      if (!evolution_function_is_invariant_rec_p (TREE_OPERAND (chrec, 0),
						  loopnum))
	return false;
      return true;

    default:
      return false;
    }

  return false;
}

static tree
chrec_convert_1 (tree type, tree chrec, gimple *at_stmt,
		 bool use_overflow_semantics)
{
  tree ct, res;
  tree base, step;
  struct loop *loop;

  if (automatically_generated_chrec_p (chrec))
    return chrec;

  ct = chrec_type (chrec);
  if (useless_type_conversion_p (type, ct))
    return chrec;

  if (!evolution_function_is_affine_p (chrec))
    goto keep_cast;

  loop = get_chrec_loop (chrec);
  base = CHREC_LEFT (chrec);
  step = CHREC_RIGHT (chrec);

  if (convert_affine_scev (loop, type, &base, &step, at_stmt,
			   use_overflow_semantics))
    return build_polynomial_chrec (loop->num, base, step);

  /* If we cannot propagate the cast inside the chrec, just keep the cast.  */
keep_cast:
  /* Fold will not canonicalize (long)(i - 1) to (long)i - 1 because that
     may be more expensive.  We do want to perform this optimization here
     though for canonicalization reasons.  */
  if (use_overflow_semantics
      && (TREE_CODE (chrec) == PLUS_EXPR
	  || TREE_CODE (chrec) == MINUS_EXPR)
      && TREE_CODE (type) == INTEGER_TYPE
      && TREE_CODE (ct) == INTEGER_TYPE
      && TYPE_PRECISION (type) > TYPE_PRECISION (ct)
      && TYPE_OVERFLOW_UNDEFINED (ct))
    res = fold_build2 (TREE_CODE (chrec), type,
		       fold_convert (type, TREE_OPERAND (chrec, 0)),
		       fold_convert (type, TREE_OPERAND (chrec, 1)));
  /* Similar perform the trick that (signed char)((int)x + 2) can be
     narrowed to (signed char)((unsigned char)x + 2).  */
  else if (use_overflow_semantics
	   && TREE_CODE (chrec) == POLYNOMIAL_CHREC
	   && TREE_CODE (ct) == INTEGER_TYPE
	   && TREE_CODE (type) == INTEGER_TYPE
	   && TYPE_OVERFLOW_UNDEFINED (type)
	   && TYPE_PRECISION (type) < TYPE_PRECISION (ct))
    {
      tree utype = unsigned_type_for (type);
      res = build_polynomial_chrec (CHREC_VARIABLE (chrec),
				    fold_convert (utype,
						  CHREC_LEFT (chrec)),
				    fold_convert (utype,
						  CHREC_RIGHT (chrec)));
      res = chrec_convert_1 (type, res, at_stmt, use_overflow_semantics);
    }
  else
    res = fold_convert (type, chrec);

  /* Don't propagate overflows.  */
  if (CONSTANT_CLASS_P (res))
    TREE_OVERFLOW (res) = 0;

  /* But reject constants that don't fit in their type after conversion.
     This can happen if TYPE_MIN_VALUE or TYPE_MAX_VALUE are not the
     natural values associated with TYPE_PRECISION and TYPE_UNSIGNED,
     and can cause problems later when computing niters of loops.  Note
     that we don't do the check before converting because we don't want
     to reject conversions of negative chrecs to unsigned types.  */
  if (TREE_CODE (res) == INTEGER_CST
      && TREE_CODE (type) == INTEGER_TYPE
      && !int_fits_type_p (res, type))
    res = chrec_dont_know;

  return res;
}