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 Methods to compute when a value will be used again.
23 * @author Sebastian Hack, Matthias Braun
42 #include "irgraph_t.h"
43 #include "iredges_t.h"
50 #include "besched_t.h"
54 #include "benodesets.h"
56 #define SCAN_INTERBLOCK_USES
58 typedef struct _be_use_t {
70 unsigned visited_counter;
71 DEBUG_ONLY(firm_dbg_module_t *dbg;)
74 static int cmp_use(const void *a, const void *b, size_t n)
76 const be_use_t *p = a;
77 const be_use_t *q = b;
78 return !(p->block == q->block && p->node == q->node);
81 static be_next_use_t get_next_use(be_uses_t *env, ir_node *from,
82 unsigned from_step, const ir_node *def,
85 static const be_use_t *get_or_set_use_block(be_uses_t *env,
89 unsigned hash = HASH_COMBINE(nodeset_hash(block), nodeset_hash(def));
95 result = set_find(env->uses, &temp, sizeof(temp), hash);
98 // insert templ first as we might end in a loop in the get_next_use
100 temp.next_use = USES_INFINITY;
101 temp.outermost_loop = -1;
103 result = set_insert(env->uses, &temp, sizeof(temp), hash);
106 if(result->outermost_loop < 0 && result->visited < env->visited_counter) {
107 be_next_use_t next_use;
109 result->visited = env->visited_counter;
110 next_use = get_next_use(env, sched_first(block), 0, def, 0);
111 if(next_use.outermost_loop >= 0) {
112 result->next_use = next_use.time;
113 result->outermost_loop = next_use.outermost_loop;
114 DBG((env->dbg, LEVEL_5, "Setting nextuse of %+F in block %+F to %u (outermostloop %d)\n", def, block, result->next_use, result->outermost_loop));
121 static int be_is_phi_argument(const be_lv_t *lv, const ir_node *block, const ir_node *def)
124 ir_node *succ_block = NULL;
125 const ir_edge_t *edge;
129 if(get_irn_n_edges_kind(block, EDGE_KIND_BLOCK) > 1)
133 foreach_block_succ(block, edge) {
134 succ_block = get_edge_src_irn(edge);
138 arity = get_Block_n_cfgpreds(succ_block);
142 for(i = 0; i < arity; ++i) {
143 if(get_Block_cfgpred_block(succ_block, i) == block)
148 sched_foreach(succ_block, node) {
154 arg = get_irn_n(node, i);
162 static be_next_use_t get_next_use(be_uses_t *env, ir_node *from,
163 unsigned from_step, const ir_node *def,
166 unsigned step = from_step;
167 ir_node *block = get_nodes_block(from);
169 const ir_edge_t *edge;
173 from = sched_next(from);
176 sched_foreach_from(from, node) {
184 arity = get_irn_arity(node);
185 for (i = 0; i < arity; ++i) {
186 const ir_node *operand = get_irn_n(node, i);
188 if (operand == def) {
189 be_next_use_t result;
191 DBG((env->dbg, LEVEL_3, "found use of %+F at %+F\n", operand, node));
194 * Spills/Reloads are a special case, they're not really a
195 * usage of a value, continue searching
197 if (be_is_Spill(node) || be_is_Reload(node)) {
198 return be_get_next_use(env, node, step, node, 1);
202 result.outermost_loop = get_loop_depth(get_irn_loop(block));
210 if(be_is_phi_argument(env->lv, block, def)) {
211 // TODO we really should continue searching the uses of the phi,
212 // as a phi isn't a real use that implies a reload (because we could
213 // easily spill the whole phi)
215 be_next_use_t result;
217 result.outermost_loop = get_loop_depth(get_irn_loop(block));
221 #ifdef SCAN_INTERBLOCK_USES
223 unsigned next_use = USES_INFINITY;
225 be_next_use_t result;
226 ir_loop *loop = get_irn_loop(block);
227 int loopdepth = get_loop_depth(loop);
228 int found_visited = 0;
230 ir_graph *irg = get_irn_irg(block);
231 ir_node *startblock = get_irg_start_block(irg);
233 outermost_loop = loopdepth;
234 foreach_block_succ(block, edge) {
236 const ir_node *succ_block = get_edge_src_irn(edge);
240 if(succ_block == startblock)
243 DBG((env->dbg, LEVEL_5, "Checking succ of block %+F: %+F (for use of %+F)\n", block, succ_block, def));
244 if(!be_is_live_in(env->lv, succ_block, def)) {
245 //next_use = USES_INFINITY;
246 DBG((env->dbg, LEVEL_5, " not live in\n"));
250 use = get_or_set_use_block(env, succ_block, def);
251 DBG((env->dbg, LEVEL_5, "Found %u (loopdepth %d) (we're in block %+F)\n", use->next_use,
252 use->outermost_loop, block));
253 if(USES_IS_INFINITE(use->next_use)) {
254 if(use->outermost_loop < 0) {
261 use_dist = use->next_use;
263 succ_loop = get_irn_loop(succ_block);
264 if(get_loop_depth(succ_loop) < loopdepth) {
265 unsigned factor = (loopdepth - get_loop_depth(succ_loop)) * 5000;
266 DBG((env->dbg, LEVEL_5, "Increase usestep because of loop out edge %d -> %d (%u)\n", factor));
267 // TODO we should use the number of nodes in the loop or so...
271 if(use_dist < next_use) {
273 outermost_loop = use->outermost_loop;
277 if(loopdepth < outermost_loop)
278 outermost_loop = loopdepth;
280 result.time = next_use + step;
281 result.outermost_loop = outermost_loop;
283 if(!found_use && found_visited) {
284 // the current result is correct for the current search, but isn't
285 // generally correct, so mark it
286 result.outermost_loop = -1;
288 DBG((env->dbg, LEVEL_5, "Result: %d (outerloop: %d)\n", result.time, result.outermost_loop));
292 return USES_INFINITY;
296 be_next_use_t be_get_next_use(be_uses_t *env, ir_node *from,
297 unsigned from_step, const ir_node *def,
300 env->visited_counter++;
301 return get_next_use(env, from, from_step, def, skip_from_uses);
304 be_uses_t *be_begin_uses(ir_graph *irg, const be_lv_t *lv)
306 be_uses_t *env = xmalloc(sizeof(env[0]));
310 env->uses = new_set(cmp_use, 512);
313 env->visited_counter = 0;
314 FIRM_DBG_REGISTER(env->dbg, "firm.be.uses");
319 void be_end_uses(be_uses_t *env)