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
22 * @brief Compute register pressure in loops.
23 * @author Christian Wuerdig
40 #include "beloopana.h"
43 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL);
45 #define HASH_LOOP_INFO(info) (HASH_PTR((info)->loop) ^ HASH_PTR((info)->cls))
47 typedef struct _be_loop_info_t {
49 const arch_register_class_t *cls;
50 unsigned max_pressure;
53 struct _be_loopana_t {
58 static int cmp_loop_info(const void *a, const void *b, size_t size)
60 const be_loop_info_t *i1 = a;
61 const be_loop_info_t *i2 = b;
64 return ! (i1->loop == i2->loop && i1->cls == i2->cls);
68 * Compute the highest register pressure in a block.
69 * @param birg The graph.
70 * @param block The block to compute pressure for.
71 * @param cls The register class to compute pressure for.
72 * @return The highest register pressure in the given block.
74 static unsigned be_compute_block_pressure(const be_irg_t *birg,
75 ir_node *block, const arch_register_class_t *cls)
77 be_lv_t *lv = be_get_birg_liveness(birg);
78 ir_nodeset_t live_nodes;
82 DBG((dbg, LEVEL_1, "Processing Block %+F\n", block));
84 /* determine largest pressure with this block */
85 ir_nodeset_init(&live_nodes);
86 be_liveness_end_of_block(lv, cls, block, &live_nodes);
87 max_live = ir_nodeset_size(&live_nodes);
89 sched_foreach_reverse(block, irn) {
95 be_liveness_transfer(cls, irn, &live_nodes);
96 cnt = ir_nodeset_size(&live_nodes);
97 max_live = MAX(cnt, max_live);
100 DBG((dbg, LEVEL_1, "Finished with Block %+F (%s %u)\n", block, cls->name, max_live));
102 ir_nodeset_destroy(&live_nodes);
107 * Compute the highest register pressure in a loop and it's sub-loops.
108 * @param loop_ana The loop ana object.
109 * @param loop The loop to compute pressure for.
110 * @param cls The register class to compute pressure for.
111 * @return The highest register pressure in the given loop.
113 static unsigned be_compute_loop_pressure(be_loopana_t *loop_ana, ir_loop *loop, const arch_register_class_t *cls)
117 be_loop_info_t *entry, key;
119 DBG((dbg, LEVEL_1, "\nProcessing Loop %d\n", loop->loop_nr));
120 assert(get_loop_n_elements(loop) > 0);
123 /* determine maximal pressure in all loop elements */
124 for (i = 0, max = get_loop_n_elements(loop); i < max; ++i) {
125 unsigned son_pressure;
126 loop_element elem = get_loop_element(loop, i);
128 if (*elem.kind == k_ir_node)
129 son_pressure = be_compute_block_pressure(loop_ana->birg, elem.node, cls);
131 assert(*elem.kind == k_ir_loop);
132 son_pressure = be_compute_loop_pressure(loop_ana, elem.son, cls);
135 pressure = MAX(pressure, son_pressure);
137 DBG((dbg, LEVEL_1, "Done with loop %d, pressure %u for class %s\n", loop->loop_nr, pressure, cls->name));
139 /* update info in set */
142 key.max_pressure = 0;
143 entry = set_insert(loop_ana->data, &key, sizeof(key), HASH_LOOP_INFO(&key));
144 entry->max_pressure = MAX(entry->max_pressure, pressure);
150 * Compute the register pressure for a class of all loops in the birg.
151 * @param birg The backend irg object
152 * @param cls The register class to compute the pressure for
153 * @return The loop analysis object.
155 be_loopana_t *be_new_loop_pressure_cls(be_irg_t *birg,
156 const arch_register_class_t *cls) {
157 ir_graph *irg = be_get_birg_irg(birg);
158 be_loopana_t *loop_ana = XMALLOC(be_loopana_t);
160 loop_ana->data = new_set(cmp_loop_info, 16);
161 loop_ana->birg = birg;
163 DBG((dbg, LEVEL_1, "\n=====================================================\n", cls->name));
164 DBG((dbg, LEVEL_1, " Computing register pressure for class %s:\n", cls->name));
165 DBG((dbg, LEVEL_1, "=====================================================\n", cls->name));
167 /* construct control flow loop tree */
168 if (! (get_irg_loopinfo_state(irg) & loopinfo_cf_consistent)) {
169 construct_cf_backedges(irg);
172 be_compute_loop_pressure(loop_ana, get_irg_loop(irg), cls);
178 * Compute the register pressure for all classes of all loops in the birg.
179 * @param birg The backend irg object
180 * @return The loop analysis object.
182 be_loopana_t *be_new_loop_pressure(be_irg_t *birg,
183 const arch_register_class_t *cls)
185 ir_graph *irg = be_get_birg_irg(birg);
186 be_loopana_t *loop_ana = XMALLOC(be_loopana_t);
187 ir_loop *irg_loop = get_irg_loop(irg);
188 const arch_env_t *arch_env = be_get_birg_arch_env(birg);
191 loop_ana->data = new_set(cmp_loop_info, 16);
192 loop_ana->birg = birg;
194 /* construct control flow loop tree */
195 if (! (get_irg_loopinfo_state(irg) & loopinfo_cf_consistent)) {
196 construct_cf_backedges(irg);
200 be_compute_loop_pressure(loop_ana, irg_loop, cls);
202 for (i = arch_env_get_n_reg_class(arch_env) - 1; i >= 0; --i) {
203 const arch_register_class_t *cls = arch_env_get_reg_class(arch_env, i);
204 DBG((dbg, LEVEL_1, "\n=====================================================\n", cls->name));
205 DBG((dbg, LEVEL_1, " Computing register pressure for class %s:\n", cls->name));
206 DBG((dbg, LEVEL_1, "=====================================================\n", cls->name));
207 be_compute_loop_pressure(loop_ana, irg_loop, cls);
215 * Returns the computed register pressure for the given class and loop.
216 * @return The pressure or INT_MAX if not found
218 unsigned be_get_loop_pressure(be_loopana_t *loop_ana, const arch_register_class_t *cls, ir_loop *loop)
220 unsigned pressure = INT_MAX;
221 be_loop_info_t *entry, key;
227 entry = set_find(loop_ana->data, &key, sizeof(key), HASH_LOOP_INFO(&key));
230 pressure = entry->max_pressure;
232 panic("Pressure not computed for given class and loop object.");
238 * Frees the loop analysis object.
240 void be_free_loop_pressure(be_loopana_t *loop_ana)
242 del_set(loop_ana->data);
246 void be_init_loopana(void)
248 FIRM_DBG_REGISTER(dbg, "firm.be.loopana");
251 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_loopana);