C++ SSA_NAME_DEF_STMT函数代码示例

static tree
get_name_for_bit_test (tree candidate)
{
  /* Skip single-use names in favor of using the name from a
     non-widening conversion definition.  */
  if (TREE_CODE (candidate) == SSA_NAME
      && has_single_use (candidate))
    {
      gimple def_stmt = SSA_NAME_DEF_STMT (candidate);
      if (is_gimple_assign (def_stmt)
	  && CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
	{
	  if (TYPE_PRECISION (TREE_TYPE (candidate))
	      <= TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
	    return gimple_assign_rhs1 (def_stmt);
	}
    }

  return candidate;
}

static bool
recognize_bits_test (gimple cond, tree *name, tree *bits, bool inv)
{
  gimple stmt;

  /* Get at the definition of the result of the bit test.  */
  if (gimple_cond_code (cond) != (inv ? EQ_EXPR : NE_EXPR)
      || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME
      || !integer_zerop (gimple_cond_rhs (cond)))
    return false;
  stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond));
  if (!is_gimple_assign (stmt)
      || gimple_assign_rhs_code (stmt) != BIT_AND_EXPR)
    return false;

  *name = get_name_for_bit_test (gimple_assign_rhs1 (stmt));
  *bits = gimple_assign_rhs2 (stmt);

  return true;
}

static void
sese_build_liveouts_use (sese region, bitmap liveouts, basic_block bb,
			 tree use)
{
  unsigned ver;
  basic_block def_bb;

  if (TREE_CODE (use) != SSA_NAME)
    return;

  ver = SSA_NAME_VERSION (use);
  def_bb = gimple_bb (SSA_NAME_DEF_STMT (use));

  if (!def_bb
      || !bb_in_sese_p (def_bb, region)
      || bb_in_sese_p (bb, region))
    return;

  bitmap_set_bit (liveouts, ver);
}

static void
build_one_array (gimple swtch, int num, tree arr_index_type, gimple phi,
		 tree tidx)
{
  tree array_type, ctor, decl, value_type, name, fetch;
  gimple load;
  gimple_stmt_iterator gsi;

  gcc_assert (info.default_values[num]);
  value_type = TREE_TYPE (info.default_values[num]);
  array_type = build_array_type (value_type, arr_index_type);

  ctor = build_constructor (array_type, info.constructors[num]);
  TREE_CONSTANT (ctor) = true;

  decl = build_decl (VAR_DECL, NULL_TREE, array_type);
  TREE_STATIC (decl) = 1;
  DECL_INITIAL (decl) = ctor;

  DECL_NAME (decl) = create_tmp_var_name ("CSWTCH");
  DECL_ARTIFICIAL (decl) = 1;
  TREE_CONSTANT (decl) = 1;
  add_referenced_var (decl);
  varpool_mark_needed_node (varpool_node (decl));
  varpool_finalize_decl (decl);
  mark_sym_for_renaming (decl);

  name = make_ssa_name (SSA_NAME_VAR (PHI_RESULT (phi)), NULL);
  info.target_inbound_names[num] = name;

  fetch = build4 (ARRAY_REF, value_type, decl, tidx, NULL_TREE,
		  NULL_TREE);
  load = gimple_build_assign (name, fetch);
  SSA_NAME_DEF_STMT (name) = load;

  gsi = gsi_for_stmt (swtch);
  gsi_insert_before (&gsi, load, GSI_SAME_STMT);
  mark_symbols_for_renaming (load);

  info.arr_ref_last = load;
}

static tree
tree_may_unswitch_on (basic_block bb, struct loop *loop)
{
  tree stmt, def, cond, use;
  basic_block def_bb;
  ssa_op_iter iter;

  /* BB must end in a simple conditional jump.  */
  stmt = last_stmt (bb);
  if (!stmt || TREE_CODE (stmt) != COND_EXPR)
    return NULL_TREE;

  /* Condition must be invariant.  */
  FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE)
    {
      def = SSA_NAME_DEF_STMT (use);
      def_bb = bb_for_stmt (def);
      if (def_bb
	  && flow_bb_inside_loop_p (loop, def_bb))
	return NULL_TREE;
    }

static gimple
input_phi (struct lto_input_block *ib, basic_block bb, struct data_in *data_in,
	   struct function *fn)
{
  unsigned HOST_WIDE_INT ix;
  tree phi_result;
  int i, len;
  gimple result;

  ix = streamer_read_uhwi (ib);
  phi_result = VEC_index (tree, SSANAMES (fn), ix);
  len = EDGE_COUNT (bb->preds);
  result = create_phi_node (phi_result, bb);
  SSA_NAME_DEF_STMT (phi_result) = result;

  /* We have to go through a lookup process here because the preds in the
     reconstructed graph are generally in a different order than they
     were in the original program.  */
  for (i = 0; i < len; i++)
    {
      tree def = stream_read_tree (ib, data_in);
      int src_index = streamer_read_uhwi (ib);
      location_t arg_loc = lto_input_location (ib, data_in);
      basic_block sbb = BASIC_BLOCK_FOR_FUNCTION (fn, src_index);

      edge e = NULL;
      int j;

      for (j = 0; j < len; j++)
	if (EDGE_PRED (bb, j)->src == sbb)
	  {
	    e = EDGE_PRED (bb, j);
	    break;
	  }

      add_phi_arg (result, def, e, arg_loc);
    }

  return result;
}

void
reserve_phi_args_for_new_edge (basic_block bb)
{
  size_t len = EDGE_COUNT (bb->preds);
  size_t cap = ideal_phi_node_len (len + 4);
  gimple_stmt_iterator gsi;

  for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
    {
      gimple_statement_phi *stmt =
	as_a <gimple_statement_phi> (gsi_stmt (gsi));

      if (len > gimple_phi_capacity (stmt))
	{
	  gimple_statement_phi *new_phi = resize_phi_node (stmt, cap);

	  /* The result of the PHI is defined by this PHI node.  */
	  SSA_NAME_DEF_STMT (gimple_phi_result (new_phi)) = new_phi;
	  gsi_set_stmt (&gsi, new_phi);

	  release_phi_node (stmt);
	  stmt = new_phi;
	}

      /* We represent a "missing PHI argument" by placing NULL_TREE in
	 the corresponding slot.  If PHI arguments were added
	 immediately after an edge is created, this zeroing would not
	 be necessary, but unfortunately this is not the case.  For
	 example, the loop optimizer duplicates several basic blocks,
	 redirects edges, and then fixes up PHI arguments later in
	 batch.  */
      SET_PHI_ARG_DEF (stmt, len - 1, NULL_TREE);
      gimple_phi_arg_set_location (stmt, len - 1, UNKNOWN_LOCATION);

      stmt->nargs++;
    }
}

static bool
add_dependency (tree def, struct lim_aux_data *data, struct loop *loop,
		bool add_cost)
{
  tree def_stmt = SSA_NAME_DEF_STMT (def);
  basic_block def_bb = bb_for_stmt (def_stmt);
  struct loop *max_loop;
  struct depend *dep;

  if (!def_bb)
    return true;

  max_loop = outermost_invariant_loop (def, loop);
  if (!max_loop)
    return false;

  if (flow_loop_nested_p (data->max_loop, max_loop))
    data->max_loop = max_loop;

  if (!LIM_DATA (def_stmt))
    return true;

  if (add_cost
      /* Only add the cost if the statement defining DEF is inside LOOP,
	 i.e. if it is likely that by moving the invariants dependent
	 on it, we will be able to avoid creating a new register for
	 it (since it will be only used in these dependent invariants).  */
      && def_bb->loop_father == loop)
    data->cost += LIM_DATA (def_stmt)->cost;

  dep = XNEW (struct depend);
  dep->stmt = def_stmt;
  dep->next = data->depends;
  data->depends = dep;

  return true;
}

static void
forward_propagate_into_cond (tree cond_expr)
{
  gcc_assert (TREE_CODE (cond_expr) == COND_EXPR);

  while (1)
    {
      tree test_var = NULL_TREE;
      tree cond = COND_EXPR_COND (cond_expr);
      tree new_cond = forward_propagate_into_cond_1 (cond, &test_var);

      /* Return if unsuccessful.  */
      if (new_cond == NULL_TREE)
	break;

      /* Dump details.  */
      if (dump_file && (dump_flags & TDF_DETAILS))
	{
	  fprintf (dump_file, "  Replaced '");
	  print_generic_expr (dump_file, cond, dump_flags);
	  fprintf (dump_file, "' with '");
	  print_generic_expr (dump_file, new_cond, dump_flags);
	  fprintf (dump_file, "'\n");
	}

      COND_EXPR_COND (cond_expr) = new_cond;
      update_stmt (cond_expr);

      if (has_zero_uses (test_var))
	{
	  tree def = SSA_NAME_DEF_STMT (test_var);
	  block_stmt_iterator bsi = bsi_for_stmt (def);
	  bsi_remove (&bsi);
	}
    }
}

/* Return 1 if check CI against BOUNDS always pass,
   -1 if check CI against BOUNDS always fails and
   0 if we cannot compute check result.  */
static int
chkp_get_check_result (struct check_info *ci, tree bounds)
{
    gimple *bnd_def;
    address_t bound_val;
    int sign, res = 0;

    if (dump_file && (dump_flags & TDF_DETAILS))
    {
        fprintf (dump_file, "Trying to compute result of the check\n");
        fprintf (dump_file, "  check: ");
        print_gimple_stmt (dump_file, ci->stmt, 0, 0);
        fprintf (dump_file, "  address: ");
        chkp_print_addr (ci->addr);
        fprintf (dump_file, "\n  bounds: ");
        print_generic_expr (dump_file, bounds, 0);
        fprintf (dump_file, "\n");
    }

    if (TREE_CODE (bounds) != SSA_NAME)
    {
        if (dump_file && (dump_flags & TDF_DETAILS))
            fprintf (dump_file, "  result: bounds tree code is not ssa_name\n");
        return 0;
    }

    bnd_def = SSA_NAME_DEF_STMT (bounds);
    /* Currently we handle cases when bounds are result of bndmk
       or loaded static bounds var.  */
    if (gimple_code (bnd_def) == GIMPLE_CALL
            && gimple_call_fndecl (bnd_def) == chkp_bndmk_fndecl)
    {
        bound_val.pol.create (0);
        chkp_collect_value (gimple_call_arg (bnd_def, 0), bound_val);
        if (ci->type == CHECK_UPPER_BOUND)
        {
            address_t size_val;
            size_val.pol.create (0);
            chkp_collect_value (gimple_call_arg (bnd_def, 1), size_val);
            chkp_add_addr_addr (bound_val, size_val);
            size_val.pol.release ();
            chkp_add_addr_item (bound_val, integer_minus_one_node, NULL);
        }
    }
    else if (gimple_code (bnd_def) == GIMPLE_ASSIGN
             && gimple_assign_rhs1 (bnd_def) == chkp_get_zero_bounds_var ())
    {
        if (dump_file && (dump_flags & TDF_DETAILS))
            fprintf (dump_file, "  result: always pass with zero bounds\n");
        return 1;
    }
    else if (gimple_code (bnd_def) == GIMPLE_ASSIGN
             && gimple_assign_rhs1 (bnd_def) == chkp_get_none_bounds_var ())
    {
        if (dump_file && (dump_flags & TDF_DETAILS))
            fprintf (dump_file, "  result: always fails with none bounds\n");
        return -1;
    }
    else if (gimple_code (bnd_def) == GIMPLE_ASSIGN
             && TREE_CODE (gimple_assign_rhs1 (bnd_def)) == VAR_DECL)
    {
        tree bnd_var = gimple_assign_rhs1 (bnd_def);
        tree var;
        tree size;

        if (!DECL_INITIAL (bnd_var)
                || DECL_INITIAL (bnd_var) == error_mark_node)
        {
            if (dump_file && (dump_flags & TDF_DETAILS))
                fprintf (dump_file, "  result: cannot compute bounds\n");
            return 0;
        }

        gcc_assert (TREE_CODE (DECL_INITIAL (bnd_var)) == ADDR_EXPR);
        var = TREE_OPERAND (DECL_INITIAL (bnd_var), 0);

        bound_val.pol.create (0);
        chkp_collect_value (DECL_INITIAL (bnd_var), bound_val);
        if (ci->type == CHECK_UPPER_BOUND)
        {
            if (TREE_CODE (var) == VAR_DECL)
            {
                if (DECL_SIZE (var)
                        && !chkp_variable_size_type (TREE_TYPE (var)))
                    size = DECL_SIZE_UNIT (var);
                else
                {
                    if (dump_file && (dump_flags & TDF_DETAILS))
                        fprintf (dump_file, "  result: cannot compute bounds\n");
                    return 0;
                }
            }
            else
            {
                gcc_assert (TREE_CODE (var) == STRING_CST);
                size = build_int_cst (size_type_node,
                                      TREE_STRING_LENGTH (var));
//.........这里部分代码省略.........

/* Compute value of PTR and put it into address RES.  */
static void
chkp_collect_value (tree ptr, address_t &res)
{
    gimple *def_stmt;
    enum gimple_code code;
    enum tree_code rhs_code;
    address_t addr;
    tree rhs1;

    if (TREE_CODE (ptr) == INTEGER_CST)
    {
        chkp_add_addr_item (res, ptr, NULL);
        return;
    }
    else if (TREE_CODE (ptr) == ADDR_EXPR)
    {
        chkp_collect_addr_value (ptr, res);
        return;
    }
    else if (TREE_CODE (ptr) != SSA_NAME)
    {
        chkp_add_addr_item (res, integer_one_node, ptr);
        return;
    }

    /* Now we handle the case when polynomial is computed
       for SSA NAME.  */
    def_stmt = SSA_NAME_DEF_STMT (ptr);
    code = gimple_code (def_stmt);

    /* Currently we do not walk through statements other
       than assignment.  */
    if (code != GIMPLE_ASSIGN)
    {
        chkp_add_addr_item (res, integer_one_node, ptr);
        return;
    }

    rhs_code = gimple_assign_rhs_code (def_stmt);
    rhs1 = gimple_assign_rhs1 (def_stmt);

    switch (rhs_code)
    {
    case SSA_NAME:
    case INTEGER_CST:
    case ADDR_EXPR:
        chkp_collect_value (rhs1, res);
        break;

    case PLUS_EXPR:
    case POINTER_PLUS_EXPR:
        chkp_collect_value (rhs1, res);
        addr.pol.create (0);
        chkp_collect_value (gimple_assign_rhs2 (def_stmt), addr);
        chkp_add_addr_addr (res, addr);
        addr.pol.release ();
        break;

    case MINUS_EXPR:
        chkp_collect_value (rhs1, res);
        addr.pol.create (0);
        chkp_collect_value (gimple_assign_rhs2 (def_stmt), addr);
        chkp_sub_addr_addr (res, addr);
        addr.pol.release ();
        break;

    case MULT_EXPR:
        if (TREE_CODE (rhs1) == SSA_NAME
                && TREE_CODE (gimple_assign_rhs2 (def_stmt)) == INTEGER_CST)
        {
            chkp_collect_value (rhs1, res);
            chkp_mult_addr (res, gimple_assign_rhs2 (def_stmt));
        }
        else if (TREE_CODE (gimple_assign_rhs2 (def_stmt)) == SSA_NAME
                 && TREE_CODE (rhs1) == INTEGER_CST)
        {
            chkp_collect_value (gimple_assign_rhs2 (def_stmt), res);
            chkp_mult_addr (res, rhs1);
        }
        else
            chkp_add_addr_item (res, integer_one_node, ptr);
        break;

    default:
        chkp_add_addr_item (res, integer_one_node, ptr);
        break;
    }
}

static tree
rewrite_bittest (block_stmt_iterator *bsi)
{
  tree stmt, lhs, rhs, var, name, use_stmt, stmt1, stmt2, t;
  use_operand_p use;

  stmt = bsi_stmt (*bsi);
  lhs = GENERIC_TREE_OPERAND (stmt, 0);
  rhs = GENERIC_TREE_OPERAND (stmt, 1);

  /* Verify that the single use of lhs is a comparison against zero.  */
  if (TREE_CODE (lhs) != SSA_NAME
      || !single_imm_use (lhs, &use, &use_stmt)
      || TREE_CODE (use_stmt) != COND_EXPR)
    return stmt;
  t = COND_EXPR_COND (use_stmt);
  if (TREE_OPERAND (t, 0) != lhs
      || (TREE_CODE (t) != NE_EXPR
	  && TREE_CODE (t) != EQ_EXPR)
      || !integer_zerop (TREE_OPERAND (t, 1)))
    return stmt;

  /* Get at the operands of the shift.  The rhs is TMP1 & 1.  */
  stmt1 = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0));
  if (TREE_CODE (stmt1) != GIMPLE_MODIFY_STMT)
    return stmt;

  /* There is a conversion in between possibly inserted by fold.  */
  t = GIMPLE_STMT_OPERAND (stmt1, 1);
  if (TREE_CODE (t) == NOP_EXPR
      || TREE_CODE (t) == CONVERT_EXPR)
    {
      t = TREE_OPERAND (t, 0);
      if (TREE_CODE (t) != SSA_NAME
	  || !has_single_use (t))
	return stmt;
      stmt1 = SSA_NAME_DEF_STMT (t);
      if (TREE_CODE (stmt1) != GIMPLE_MODIFY_STMT)
	return stmt;
      t = GIMPLE_STMT_OPERAND (stmt1, 1);
    }

  /* Verify that B is loop invariant but A is not.  Verify that with
     all the stmt walking we are still in the same loop.  */
  if (TREE_CODE (t) == RSHIFT_EXPR
      && loop_containing_stmt (stmt1) == loop_containing_stmt (stmt)
      && outermost_invariant_loop_expr (TREE_OPERAND (t, 1),
                                        loop_containing_stmt (stmt1)) != NULL
      && outermost_invariant_loop_expr (TREE_OPERAND (t, 0),
                                        loop_containing_stmt (stmt1)) == NULL)
    {
      tree a = TREE_OPERAND (t, 0);
      tree b = TREE_OPERAND (t, 1);

      /* 1 << B */
      var = create_tmp_var (TREE_TYPE (a), "shifttmp");
      add_referenced_var (var);
      t = fold_build2 (LSHIFT_EXPR, TREE_TYPE (a),
		       build_int_cst (TREE_TYPE (a), 1), b);
      stmt1 = build_gimple_modify_stmt (var, t);
      name = make_ssa_name (var, stmt1);
      GIMPLE_STMT_OPERAND (stmt1, 0) = name;

      /* A & (1 << B) */
      t = fold_build2 (BIT_AND_EXPR, TREE_TYPE (a), a, name);
      stmt2 = build_gimple_modify_stmt (var, t);
      name = make_ssa_name (var, stmt2);
      GIMPLE_STMT_OPERAND (stmt2, 0) = name;

      /* Replace the SSA_NAME we compare against zero.  Adjust
	 the type of zero accordingly.  */
      SET_USE (use, name);
      TREE_OPERAND (COND_EXPR_COND (use_stmt), 1)
	= build_int_cst_type (TREE_TYPE (name), 0);

      bsi_insert_before (bsi, stmt1, BSI_SAME_STMT);
      bsi_replace (bsi, stmt2, true);

      return stmt1;
    }

  return stmt;
}

static bool
recognize_single_bit_test (gimple cond, tree *name, tree *bit)
{
  gimple stmt;

  /* Get at the definition of the result of the bit test.  */
  if (gimple_cond_code (cond) != NE_EXPR
      || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME
      || !integer_zerop (gimple_cond_rhs (cond)))
    return false;
  stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond));
  if (!is_gimple_assign (stmt))
    return false;

  /* Look at which bit is tested.  One form to recognize is
     D.1985_5 = state_3(D) >> control1_4(D);
     D.1986_6 = (int) D.1985_5;
     D.1987_7 = op0 & 1;
     if (D.1987_7 != 0)  */
  if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR
      && integer_onep (gimple_assign_rhs2 (stmt))
      && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME)
    {
      tree orig_name = gimple_assign_rhs1 (stmt);

      /* Look through copies and conversions to eventually
	 find the stmt that computes the shift.  */
      stmt = SSA_NAME_DEF_STMT (orig_name);

      while (is_gimple_assign (stmt)
	     && ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt))
		  && (TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (stmt)))
		      <= TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (stmt)))))
		 || gimple_assign_ssa_name_copy_p (stmt)))
	stmt = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt));

      /* If we found such, decompose it.  */
      if (is_gimple_assign (stmt)
	  && gimple_assign_rhs_code (stmt) == RSHIFT_EXPR)
	{
	  /* op0 & (1 << op1) */
	  *bit = gimple_assign_rhs2 (stmt);
	  *name = gimple_assign_rhs1 (stmt);
	}
      else
	{
	  /* t & 1 */
	  *bit = integer_zero_node;
	  *name = get_name_for_bit_test (orig_name);
	}

      return true;
    }

  /* Another form is
     D.1987_7 = op0 & (1 << CST)
     if (D.1987_7 != 0)  */
  if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR
      && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
      && integer_pow2p (gimple_assign_rhs2 (stmt)))
    {
      *name = gimple_assign_rhs1 (stmt);
      *bit = build_int_cst (integer_type_node,
			    tree_log2 (gimple_assign_rhs2 (stmt)));
      return true;
    }

  /* Another form is
     D.1986_6 = 1 << control1_4(D)
     D.1987_7 = op0 & D.1986_6
     if (D.1987_7 != 0)  */
  if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR
      && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
      && TREE_CODE (gimple_assign_rhs2 (stmt)) == SSA_NAME)
    {
      gimple tmp;

      /* Both arguments of the BIT_AND_EXPR can be the single-bit
	 specifying expression.  */
      tmp = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt));
      if (is_gimple_assign (tmp)
	  && gimple_assign_rhs_code (tmp) == LSHIFT_EXPR
	  && integer_onep (gimple_assign_rhs1 (tmp)))
	{
	  *name = gimple_assign_rhs2 (stmt);
	  *bit = gimple_assign_rhs2 (tmp);
	  return true;
	}

      tmp = SSA_NAME_DEF_STMT (gimple_assign_rhs2 (stmt));
      if (is_gimple_assign (tmp)
	  && gimple_assign_rhs_code (tmp) == LSHIFT_EXPR
	  && integer_onep (gimple_assign_rhs1 (tmp)))
	{
	  *name = gimple_assign_rhs1 (stmt);
	  *bit = gimple_assign_rhs2 (tmp);
	  return true;
	}
    }

//.........这里部分代码省略.........

static bool
forward_propagate_addr_into_variable_array_index (tree offset,
						  tree def_rhs,
						  gimple_stmt_iterator *use_stmt_gsi)
{
  tree index, tunit;
  gimple offset_def, use_stmt = gsi_stmt (*use_stmt_gsi);
  tree tmp;

  tunit = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (def_rhs)));
  if (!host_integerp (tunit, 1))
    return false;

  /* Get the offset's defining statement.  */
  offset_def = SSA_NAME_DEF_STMT (offset);

  /* Try to find an expression for a proper index.  This is either a
     multiplication expression by the element size or just the ssa name we came
     along in case the element size is one. In that case, however, we do not
     allow multiplications because they can be computing index to a higher
     level dimension (PR 37861). */
  if (integer_onep (tunit))
    {
      if (is_gimple_assign (offset_def)
	  && gimple_assign_rhs_code (offset_def) == MULT_EXPR)
	return false;

      index = offset;
    }
  else
    {
      /* The statement which defines OFFSET before type conversion
         must be a simple GIMPLE_ASSIGN.  */
      if (!is_gimple_assign (offset_def))
	return false;

      /* The RHS of the statement which defines OFFSET must be a
	 multiplication of an object by the size of the array elements.
	 This implicitly verifies that the size of the array elements
	 is constant.  */
     if (gimple_assign_rhs_code (offset_def) == MULT_EXPR
	 && TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST
	 && tree_int_cst_equal (gimple_assign_rhs2 (offset_def), tunit))
       {
	 /* The first operand to the MULT_EXPR is the desired index.  */
	 index = gimple_assign_rhs1 (offset_def);
       }
     /* If we have idx * tunit + CST * tunit re-associate that.  */
     else if ((gimple_assign_rhs_code (offset_def) == PLUS_EXPR
	       || gimple_assign_rhs_code (offset_def) == MINUS_EXPR)
	      && TREE_CODE (gimple_assign_rhs1 (offset_def)) == SSA_NAME
	      && TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST
	      && (tmp = div_if_zero_remainder (EXACT_DIV_EXPR,
					       gimple_assign_rhs2 (offset_def),
					       tunit)) != NULL_TREE)
       {
	 gimple offset_def2 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (offset_def));
	 if (is_gimple_assign (offset_def2)
	     && gimple_assign_rhs_code (offset_def2) == MULT_EXPR
	     && TREE_CODE (gimple_assign_rhs2 (offset_def2)) == INTEGER_CST
	     && tree_int_cst_equal (gimple_assign_rhs2 (offset_def2), tunit))
	   {
	     index = fold_build2 (gimple_assign_rhs_code (offset_def),
				  TREE_TYPE (offset),
				  gimple_assign_rhs1 (offset_def2), tmp);
	   }
	 else
	   return false;
       }
     else
	return false;
    }

  /* Replace the pointer addition with array indexing.  */
  index = force_gimple_operand_gsi (use_stmt_gsi, index, true, NULL_TREE,
				    true, GSI_SAME_STMT);
  gimple_assign_set_rhs_from_tree (use_stmt_gsi, unshare_expr (def_rhs));
  use_stmt = gsi_stmt (*use_stmt_gsi);
  TREE_OPERAND (TREE_OPERAND (gimple_assign_rhs1 (use_stmt), 0), 1)
    = index;

  /* That should have created gimple, so there is no need to
     record information to undo the propagation.  */
  fold_stmt_inplace (use_stmt);
  tidy_after_forward_propagate_addr (use_stmt);
  return true;
}

static gimple
vect_recog_widen_sum_pattern (gimple last_stmt, tree *type_in, tree *type_out)
{
  gimple stmt;
  tree oprnd0, oprnd1;
  stmt_vec_info stmt_vinfo = vinfo_for_stmt (last_stmt);
  tree type, half_type;
  gimple pattern_stmt;
  loop_vec_info loop_info = STMT_VINFO_LOOP_VINFO (stmt_vinfo);
  struct loop *loop = LOOP_VINFO_LOOP (loop_info);
  tree var;

  if (!is_gimple_assign (last_stmt))
    return NULL;

  type = gimple_expr_type (last_stmt);

  /* Look for the following pattern
          DX = (TYPE) X;
          sum_1 = DX + sum_0;
     In which DX is at least double the size of X, and sum_1 has been
     recognized as a reduction variable.
   */

  /* Starting from LAST_STMT, follow the defs of its uses in search
     of the above pattern.  */

  if (gimple_assign_rhs_code (last_stmt) != PLUS_EXPR)
    return NULL;

  if (STMT_VINFO_DEF_TYPE (stmt_vinfo) != vect_reduction_def)
    return NULL;

  oprnd0 = gimple_assign_rhs1 (last_stmt);
  oprnd1 = gimple_assign_rhs2 (last_stmt);
  if (!types_compatible_p (TREE_TYPE (oprnd0), type)
      || !types_compatible_p (TREE_TYPE (oprnd1), type))
    return NULL;

  /* So far so good. Since last_stmt was detected as a (summation) reduction,
     we know that oprnd1 is the reduction variable (defined by a loop-header
     phi), and oprnd0 is an ssa-name defined by a stmt in the loop body.
     Left to check that oprnd0 is defined by a cast from type 'type' to type
     'TYPE'.  */

  if (!widened_name_p (oprnd0, last_stmt, &half_type, &stmt))
    return NULL;

  oprnd0 = gimple_assign_rhs1 (stmt);
  *type_in = half_type;
  *type_out = type;

  /* Pattern detected. Create a stmt to be used to replace the pattern: */
  var = vect_recog_temp_ssa_var (type, NULL);
  pattern_stmt = gimple_build_assign_with_ops (WIDEN_SUM_EXPR, var,
					       oprnd0, oprnd1);
  SSA_NAME_DEF_STMT (var) = pattern_stmt;

  if (vect_print_dump_info (REPORT_DETAILS))
    {
      fprintf (vect_dump, "vect_recog_widen_sum_pattern: detected: ");
      print_gimple_stmt (vect_dump, pattern_stmt, 0, TDF_SLIM);
    }

  /* We don't allow changing the order of the computation in the inner-loop
     when doing outer-loop vectorization.  */
  gcc_assert (!nested_in_vect_loop_p (loop, last_stmt));

  return pattern_stmt;
}