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;
80 return !(p->block == q->block && p->node == q->node);
83 static be_next_use_t get_next_use(be_uses_t *env, ir_node *from,
84 unsigned from_step, const ir_node *def,
87 static const be_use_t *get_or_set_use_block(be_uses_t *env,
91 unsigned hash = HASH_COMBINE(nodeset_hash(block), nodeset_hash(def));
97 result = set_find(env->uses, &temp, sizeof(temp), hash);
100 // insert templ first as we might end in a loop in the get_next_use
102 temp.next_use = USES_INFINITY;
103 temp.outermost_loop = -1;
105 result = set_insert(env->uses, &temp, sizeof(temp), hash);
108 if(result->outermost_loop < 0 && result->visited < env->visited_counter) {
109 be_next_use_t next_use;
111 result->visited = env->visited_counter;
112 next_use = get_next_use(env, sched_first(block), 0, def, 0);
113 if(next_use.outermost_loop >= 0) {
114 result->next_use = next_use.time;
115 result->outermost_loop = next_use.outermost_loop;
116 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));
123 static int be_is_phi_argument(const ir_node *block, const ir_node *def)
126 ir_node *succ_block = NULL;
127 const ir_edge_t *edge;
131 if(get_irn_n_edges_kind(block, EDGE_KIND_BLOCK) > 1)
135 foreach_block_succ(block, edge) {
136 succ_block = get_edge_src_irn(edge);
140 arity = get_Block_n_cfgpreds(succ_block);
144 for(i = 0; i < arity; ++i) {
145 if(get_Block_cfgpred_block(succ_block, i) == block)
150 sched_foreach(succ_block, node) {
156 arg = get_irn_n(node, i);
165 unsigned get_step(const ir_node *node)
167 return PTR_TO_INT(get_irn_link(node));
170 static be_next_use_t get_next_use(be_uses_t *env, ir_node *from,
171 unsigned from_step, const ir_node *def,
174 unsigned step = from_step;
175 ir_node *block = get_nodes_block(from);
179 unsigned next_use_step;
180 const ir_edge_t *edge;
183 assert(skip_from_uses == 0 || skip_from_uses == 1);
185 from = sched_next(from);
189 next_use_step = INT_MAX;
190 timestep = get_step(from);
191 foreach_out_edge(def, edge) {
192 ir_node *node = get_edge_src_irn(edge);
197 if(get_nodes_block(node) != block)
202 node_step = get_step(node);
203 if(node_step < timestep)
205 if(node_step < next_use_step) {
207 next_use_step = node_step;
211 if(next_use != NULL) {
212 be_next_use_t result;
213 result.time = next_use_step - timestep + skip_from_uses;
214 result.outermost_loop = get_loop_depth(get_irn_loop(block));
218 node = sched_last(block);
219 step = get_step(node) + 1 + timestep + skip_from_uses;
223 from = sched_next(from);
227 sched_foreach_from(from, node) {
235 arity = get_irn_arity(node);
236 for (i = 0; i < arity; ++i) {
237 const ir_node *operand = get_irn_n(node, i);
239 if (operand == def) {
240 be_next_use_t result;
242 DBG((env->dbg, LEVEL_3, "found use of %+F at %+F\n", operand, node));
245 * Spills/Reloads are a special case, they're not really a
246 * usage of a value, continue searching
248 if (be_is_Spill(node) || be_is_Reload(node)) {
249 return be_get_next_use(env, node, step, node, 1);
253 result.outermost_loop = get_loop_depth(get_irn_loop(block));
262 if(be_is_phi_argument(block, def)) {
263 // TODO we really should continue searching the uses of the phi,
264 // as a phi isn't a real use that implies a reload (because we could
265 // easily spill the whole phi)
267 be_next_use_t result;
269 result.outermost_loop = get_loop_depth(get_irn_loop(block));
273 #ifdef SCAN_INTERBLOCK_USES
275 unsigned next_use = USES_INFINITY;
277 be_next_use_t result;
278 ir_loop *loop = get_irn_loop(block);
279 int loopdepth = get_loop_depth(loop);
280 int found_visited = 0;
282 ir_graph *irg = get_irn_irg(block);
283 ir_node *startblock = get_irg_start_block(irg);
285 outermost_loop = loopdepth;
286 foreach_block_succ(block, edge) {
288 const ir_node *succ_block = get_edge_src_irn(edge);
292 if(succ_block == startblock)
295 DBG((env->dbg, LEVEL_5, "Checking succ of block %+F: %+F (for use of %+F)\n", block, succ_block, def));
296 if(!be_is_live_in(env->lv, succ_block, def)) {
297 //next_use = USES_INFINITY;
298 DBG((env->dbg, LEVEL_5, " not live in\n"));
302 use = get_or_set_use_block(env, succ_block, def);
303 DBG((env->dbg, LEVEL_5, "Found %u (loopdepth %d) (we're in block %+F)\n", use->next_use,
304 use->outermost_loop, block));
305 if(USES_IS_INFINITE(use->next_use)) {
306 if(use->outermost_loop < 0) {
313 use_dist = use->next_use;
315 succ_loop = get_irn_loop(succ_block);
316 if(get_loop_depth(succ_loop) < loopdepth) {
317 unsigned factor = (loopdepth - get_loop_depth(succ_loop)) * 5000;
318 DBG((env->dbg, LEVEL_5, "Increase usestep because of loop out edge %d -> %d (%u)\n", factor));
319 // TODO we should use the number of nodes in the loop or so...
323 if(use_dist < next_use) {
325 outermost_loop = use->outermost_loop;
329 if(loopdepth < outermost_loop)
330 outermost_loop = loopdepth;
332 result.time = next_use + step;
333 result.outermost_loop = outermost_loop;
335 if(!found_use && found_visited) {
336 // the current result is correct for the current search, but isn't
337 // generally correct, so mark it
338 result.outermost_loop = -1;
340 DBG((env->dbg, LEVEL_5, "Result: %d (outerloop: %d)\n", result.time, result.outermost_loop));
344 return USES_INFINITY;
348 be_next_use_t be_get_next_use(be_uses_t *env, ir_node *from,
349 unsigned from_step, const ir_node *def,
352 env->visited_counter++;
353 return get_next_use(env, from, from_step, def, skip_from_uses);
357 void set_sched_step_walker(ir_node *block, void *data)
363 sched_foreach(block, node) {
364 set_irn_link(node, INT_TO_PTR(step));
373 be_uses_t *be_begin_uses(ir_graph *irg, const be_lv_t *lv)
375 be_uses_t *env = xmalloc(sizeof(env[0]));
379 //set_using_irn_link(irg);
381 /* precalculate sched steps */
382 irg_block_walk_graph(irg, set_sched_step_walker, NULL, NULL);
384 env->uses = new_set(cmp_use, 512);
387 env->visited_counter = 0;
388 FIRM_DBG_REGISTER(env->dbg, "firm.be.uses");
393 void be_end_uses(be_uses_t *env)
395 //clear_using_irn_link(env->irg);