2 * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
21 * @brief Remove all Bad nodes from ir graph
22 * @author Andreas Zwinkau
37 * Return the number of non-Bad predecessors of the given node.
39 static int count_non_bads(ir_node *node)
41 int arity = get_Block_n_cfgpreds(node);
44 for (i = 0; i < arity; ++i) {
45 if (!is_Bad(get_irn_n(node, i)))
52 * Block-walker, remove Bad block predecessors and shorten Phis.
53 * Phi links must be uptodate.
55 static void block_remove_bads(ir_node *block)
57 ir_graph *irg = get_irn_irg(block);
58 const int max = get_Block_n_cfgpreds(block);
59 const int new_max = count_non_bads(block);
60 ir_node **new_in = ALLOCAN(ir_node*, new_max);
66 ir_entity *block_entity;
67 assert(max >= new_max);
69 /* 1. Create a new block without Bad inputs */
70 for (i = j = 0; i < max; ++i) {
71 ir_node *const block_pred = get_Block_cfgpred(block, i);
72 if (!is_Bad(block_pred)) {
73 new_in[j++] = block_pred;
78 /* If the end block is unreachable, it might have zero predecessors. */
80 ir_node *end_block = get_irg_end_block(irg);
81 if (block == end_block) {
82 set_irn_in(block, new_max, new_in);
87 new_block = new_r_Block(irg, new_max, new_in);
88 block_entity = get_Block_entity(block);
90 set_Block_entity(new_block, block_entity);
92 /* 2. Remove inputs on Phis, where the block input is Bad. */
93 for (phi = get_Block_phis(block); phi != NULL; phi = next) {
96 next = get_Phi_next(phi);
97 assert(get_irn_arity(phi) == max);
99 for (i = j = 0; i < max; ++i) {
100 ir_node *const block_pred = get_Block_cfgpred(block, i);
101 if (!is_Bad(block_pred)) {
102 ir_node *pred = get_irn_n(phi, i);
106 assert(j == new_max);
108 new_phi = new_r_Phi(new_block, new_max, new_in, get_irn_mode(phi));
109 exchange(phi, new_phi);
112 exchange(block, new_block);
115 static void collect(ir_node *node, void *env)
117 firm_collect_block_phis(node, NULL);
118 if (is_Block(node)) {
119 ir_node ***blocks_to_process = (ir_node***)env;
120 int arity = get_Block_n_cfgpreds(node);
121 int non_bads = count_non_bads(node);
122 if (arity != non_bads)
123 ARR_APP1(ir_node*, *blocks_to_process, node);
127 void remove_bads(ir_graph *irg)
131 ir_node **blocks_to_process = NEW_ARR_F(ir_node*, 0);
133 /* build phi list per block */
134 irg_walk_graph(irg, firm_clear_block_phis, collect, &blocks_to_process);
136 n_to_process = ARR_LEN(blocks_to_process);
137 for (i = 0; i < n_to_process; ++i) {
138 ir_node *block = blocks_to_process[i];
139 block_remove_bads(block);
141 DEL_ARR_F(blocks_to_process);
143 if (n_to_process > 0) {
144 edges_deactivate(irg);
145 clear_irg_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_OUTS);
146 clear_irg_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_DOMINANCE);
148 add_irg_properties(irg, IR_GRAPH_PROPERTY_NO_BADS);