Exemplo n.º 1
0
static bool
generate_builtin (struct loop *loop, bitmap partition, bool copy_p)
{
  bool res = false;
  unsigned i, x = 0;
  basic_block *bbs;
  gimple write = NULL;
  tree op0, op1;
  gimple_stmt_iterator bsi;
  tree nb_iter = number_of_exit_cond_executions (loop);

  if (!nb_iter || nb_iter == chrec_dont_know)
    return false;

  bbs = get_loop_body_in_dom_order (loop);

  for (i = 0; i < loop->num_nodes; i++)
    {
      basic_block bb = bbs[i];

      for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi))
	x++;

      for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
	{
	  gimple stmt = gsi_stmt (bsi);

	  if (bitmap_bit_p (partition, x++)
	      && is_gimple_assign (stmt)
	      && !is_gimple_reg (gimple_assign_lhs (stmt)))
	    {
	      /* Don't generate the builtins when there are more than
		 one memory write.  */
	      if (write != NULL)
		goto end;

	      write = stmt;
	    }
	}
    }

  if (!write)
    goto end;

  op0 = gimple_assign_lhs (write);
  op1 = gimple_assign_rhs1 (write);

  if (!(TREE_CODE (op0) == ARRAY_REF
	|| TREE_CODE (op0) == INDIRECT_REF))
    goto end;

  /* The new statements will be placed before LOOP.  */
  bsi = gsi_last_bb (loop_preheader_edge (loop)->src);

  if (gimple_assign_rhs_code (write) == INTEGER_CST
      && (integer_zerop (op1) || real_zerop (op1)))
    res = generate_memset_zero (write, op0, nb_iter, bsi);

  /* If this is the last partition for which we generate code, we have
     to destroy the loop.  */
  if (res && !copy_p)
    {
      unsigned nbbs = loop->num_nodes;
      basic_block src = loop_preheader_edge (loop)->src;
      basic_block dest = single_exit (loop)->dest;
      prop_phis (dest);
      make_edge (src, dest, EDGE_FALLTHRU);
      cancel_loop_tree (loop);

      for (i = 0; i < nbbs; i++)
	delete_basic_block (bbs[i]);

      set_immediate_dominator (CDI_DOMINATORS, dest,
			       recompute_dominator (CDI_DOMINATORS, dest));
    }

 end:
  free (bbs);
  return res;
}
static bool
abs_replacement (basic_block cond_bb, basic_block middle_bb,
                 edge e0 ATTRIBUTE_UNUSED, edge e1,
                 gimple phi, tree arg0, tree arg1)
{
    tree result;
    gimple new_stmt, cond;
    gimple_stmt_iterator gsi;
    edge true_edge, false_edge;
    gimple assign;
    edge e;
    tree rhs, lhs;
    bool negate;
    enum tree_code cond_code;

    /* If the type says honor signed zeros we cannot do this
       optimization.  */
    if (HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg1))))
        return false;

    /* OTHER_BLOCK must have only one executable statement which must have the
       form arg0 = -arg1 or arg1 = -arg0.  */

    assign = last_and_only_stmt (middle_bb);
    /* If we did not find the proper negation assignment, then we can not
       optimize.  */
    if (assign == NULL)
        return false;

    /* If we got here, then we have found the only executable statement
       in OTHER_BLOCK.  If it is anything other than arg = -arg1 or
       arg1 = -arg0, then we can not optimize.  */
    if (gimple_code (assign) != GIMPLE_ASSIGN)
        return false;

    lhs = gimple_assign_lhs (assign);

    if (gimple_assign_rhs_code (assign) != NEGATE_EXPR)
        return false;

    rhs = gimple_assign_rhs1 (assign);

    /* The assignment has to be arg0 = -arg1 or arg1 = -arg0.  */
    if (!(lhs == arg0 && rhs == arg1)
            && !(lhs == arg1 && rhs == arg0))
        return false;

    cond = last_stmt (cond_bb);
    result = PHI_RESULT (phi);

    /* Only relationals comparing arg[01] against zero are interesting.  */
    cond_code = gimple_cond_code (cond);
    if (cond_code != GT_EXPR && cond_code != GE_EXPR
            && cond_code != LT_EXPR && cond_code != LE_EXPR)
        return false;

    /* Make sure the conditional is arg[01] OP y.  */
    if (gimple_cond_lhs (cond) != rhs)
        return false;

    if (FLOAT_TYPE_P (TREE_TYPE (gimple_cond_rhs (cond)))
            ? real_zerop (gimple_cond_rhs (cond))
            : integer_zerop (gimple_cond_rhs (cond)))
        ;
    else
        return false;

    /* We need to know which is the true edge and which is the false
       edge so that we know if have abs or negative abs.  */
    extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge);

    /* For GT_EXPR/GE_EXPR, if the true edge goes to OTHER_BLOCK, then we
       will need to negate the result.  Similarly for LT_EXPR/LE_EXPR if
       the false edge goes to OTHER_BLOCK.  */
    if (cond_code == GT_EXPR || cond_code == GE_EXPR)
        e = true_edge;
    else
        e = false_edge;

    if (e->dest == middle_bb)
        negate = true;
    else
        negate = false;

    result = duplicate_ssa_name (result, NULL);

    if (negate)
    {
        tree tmp = create_tmp_var (TREE_TYPE (result), NULL);
        add_referenced_var (tmp);
        lhs = make_ssa_name (tmp, NULL);
    }
    else
        lhs = result;

    /* Build the modify expression with abs expression.  */
    new_stmt = gimple_build_assign_with_ops (ABS_EXPR, lhs, rhs, NULL);

    gsi = gsi_last_bb (cond_bb);
    gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT);

    if (negate)
    {
        /* Get the right GSI.  We want to insert after the recently
        added ABS_EXPR statement (which we know is the first statement
         in the block.  */
        new_stmt = gimple_build_assign_with_ops (NEGATE_EXPR, result, lhs, NULL);

        gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT);
    }

    replace_phi_edge_with_variable (cond_bb, e1, phi, result);

    /* Note that we optimized this PHI.  */
    return true;
}