2 * Copyright (C) 1995-2007 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
22 * @brief Construction of Confirm nodes
23 * @author Michael Beck
31 #include "irgraph_t.h"
35 #include "iropt_dbg.h"
36 #include "iredges_t.h"
43 typedef struct _env_t {
44 unsigned num_confirms; /**< number of inserted Confirm nodes */
45 unsigned num_consts; /**< number of constants placed */
46 unsigned num_eq; /**< number of equalities placed */
50 * Return the effective use block of a node and it's predecessor on
53 * @param node the node
54 * @param pos the position of the used input
56 * This handles correctly Phi nodes.
58 static ir_node *get_effective_use_block(ir_node *node, int pos)
60 /* the effective use of a Phi is in its predecessor block */
62 return get_nodes_block(get_irn_n(node, pos));
64 return get_nodes_block(node);
68 * Handle a CASE-branch.
70 * @param block the block which is entered by the branch
71 * @param irn the node expressing the switch value
72 * @param nr the branch label
73 * @param env statistical environment
75 * Branch labels are a simple case. We can replace the value
76 * by a Const with the branch label.
78 static void handle_case(ir_node *block, ir_node *irn, long nr, env_t *env)
80 const ir_edge_t *edge, *next;
86 for (edge = get_irn_out_edge_first(irn); edge; edge = next) {
87 ir_node *succ = get_edge_src_irn(edge);
88 int pos = get_edge_src_pos(edge);
89 ir_node *blk = get_effective_use_block(succ, pos);
91 next = get_irn_out_edge_next(irn, edge);
93 if (block_dominates(block, blk)) {
95 * Ok, we found a user of irn that is placed
96 * in a block dominated by the branch block.
97 * We can replace the input with the Constant
102 ir_mode *mode = get_irn_mode(irn);
103 ir_type *tp = get_irn_type(irn);
104 tarval *tv = new_tarval_from_long(nr, mode);
105 c = new_r_Const_type(current_ir_graph, block, mode, tv, tp);
108 set_irn_n(succ, pos, c);
109 DBG_OPT_CONFIRM_C(irn, c);
110 // ir_printf("1 Replacing input %d of node %n with %n\n", pos, succ, c);
112 env->num_consts += 1;
118 * Handle an IF-branch.
120 * @param block the block which is entered by the branch
121 * @param cmp the Cmp node expressing the branch condition
122 * @param pnc the Compare relation for taking this branch
123 * @param env statistical environment
125 static void handle_if(ir_node *block, ir_node *cmp, pn_Cmp pnc, env_t *env)
127 ir_node *left = get_Cmp_left(cmp);
128 ir_node *right = get_Cmp_right(cmp);
130 const ir_edge_t *edge, *next;
133 if (is_Bad(left) ||is_Bad(right))
136 op = get_irn_op(left);
138 /* Do not create Confirm nodes for Cmp(Const, Const) constructs.
139 These are removed anyway */
140 if (op == op_Const && is_Const(right))
143 /* try to place the constant on the right side for a Confirm */
144 if (op == op_Const || op == op_SymConst) {
150 pnc = get_inversed_pnc(pnc);
154 * First case: both values are identical.
155 * replace the left one by the right (potentially const) one.
157 if (pnc == pn_Cmp_Eq) {
158 for (edge = get_irn_out_edge_first(left); edge; edge = next) {
159 ir_node *succ = get_edge_src_irn(edge);
160 int pos = get_edge_src_pos(edge);
161 ir_node *blk = get_effective_use_block(succ, pos);
163 next = get_irn_out_edge_next(left, edge);
164 if (block_dominates(block, blk)) {
166 * Ok, we found a usage of left in a block
167 * dominated by the branch block.
168 * We can replace the input with right.
170 set_irn_n(succ, pos, right);
171 DBG_OPT_CONFIRM(left, right);
173 // ir_printf("2 Replacing input %d of node %n with %n\n", pos, succ, right);
179 else { /* not pn_Cmp_Eq cases */
182 for (edge = get_irn_out_edge_first(left); edge; edge = next) {
183 ir_node *succ = get_edge_src_irn(edge);
184 int pos = get_edge_src_pos(edge);
185 ir_node *blk = get_effective_use_block(succ, pos);
187 next = get_irn_out_edge_next(left, edge);
188 if (block_dominates(block, blk)) {
190 * Ok, we found a usage of left in a block
191 * dominated by the branch block.
192 * We can replace the input with a Confirm(left, pnc, right).
195 c = new_r_Confirm(current_ir_graph, block, left, right, pnc);
197 pos = get_edge_src_pos(edge);
198 set_irn_n(succ, pos, c);
199 // ir_printf("3 Replacing input %d of node %n with %n\n", pos, succ, c);
201 env->num_confirms += 1;
208 * Pre-walker: Called for every block to insert Confirm nodes
210 static void insert_Confirm(ir_node *block, void *env)
212 ir_node *cond, *proj, *selector;
216 * we can only handle blocks with only ONE control flow
219 if (get_Block_n_cfgpreds(block) != 1)
222 proj = get_Block_cfgpred(block, 0);
223 if (get_irn_op(proj) != op_Proj)
226 cond = get_Proj_pred(proj);
227 if (get_irn_op(cond) != op_Cond)
230 selector = get_Cond_selector(cond);
231 mode = get_irn_mode(selector);
233 if (mode == mode_b) {
237 /* this should be an IF, check this */
238 if (get_irn_op(selector) != op_Proj)
241 cmp = get_Proj_pred(selector);
242 if (get_irn_op(cmp) != op_Cmp)
245 pnc = get_Proj_proj(selector);
247 if (get_Proj_proj(proj) != pn_Cond_true) {
248 /* it's the false branch */
249 pnc = get_negated_pnc(pnc, mode);
251 // ir_printf("At %n using %n Confirm %=\n", block, cmp, pnc);
253 handle_if(block, cmp, pnc, env);
255 else if (mode_is_int(mode)) {
256 long proj_nr = get_Proj_proj(proj);
258 /* this is a CASE, but we cannot handle the default case */
259 if (proj_nr == get_Cond_defaultProj(cond))
262 handle_case(block, get_Cond_selector(cond), proj_nr, env);
264 } /* insert_Confirm */
267 * Construct Confirm nodes
269 void construct_confirms(ir_graph *irg)
272 int edges_active = edges_activated(irg);
274 /* we need dominance info */
277 assert(get_irg_pinned(irg) == op_pin_state_pinned &&
278 "Nodes must be placed to insert Confirms");
280 if (! edges_active) {
285 env.num_confirms = 0;
289 /* now, visit all blocks and add Confirms where possible */
290 irg_block_walk_graph(irg, insert_Confirm, NULL, &env);
292 if (env.num_confirms | env.num_consts | env.num_eq) {
293 /* we have add nodes or changed DF edges */
294 set_irg_outs_inconsistent(irg);
296 /* the new nodes are not in the loop info */
297 set_irg_loopinfo_inconsistent(irg);
301 printf("# Confirms inserted : %u\n", env.num_confirms);
302 printf("# Const replacements: %u\n", env.num_consts);
303 printf("# node equalities : %u\n", env.num_eq);
306 /* deactivate edges if they where off */
308 edges_deactivate(irg);
309 } /* construct_confirms */
312 * Post-walker: Remove Confirm nodes
314 static void rem_Confirm(ir_node *n, void *env) {
316 if (get_irn_op(n) == op_Confirm) {
317 ir_node *value = get_Confirm_value(n);
322 * Strange: a Confirm is it's own bound. This can happen
323 * in dead blocks when Phi nodes are already removed.
325 exchange(n, new_Bad());
331 * Remove all Confirm nodes from a graph.
333 void remove_confirms(ir_graph *irg) {
334 irg_walk_graph(irg, NULL, rem_Confirm, NULL);
335 } /* remove_confirms */