2 * Author: Christian Wuerdig
4 * Copyright: (c) Universitaet Karlsruhe
5 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
8 * Compute register pressure in loops
24 #include "beloopana.h"
27 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL);
29 #define HASH_LOOP_INFO(info) (HASH_PTR((info)->loop) ^ HASH_PTR((info)->cls))
31 typedef struct _be_loop_info_t {
33 const arch_register_class_t *cls;
34 unsigned max_pressure;
37 struct _be_loopana_t {
42 static int cmp_loop_info(const void *a, const void *b, size_t sz) {
43 const be_loop_info_t *i1 = a;
44 const be_loop_info_t *i2 = b;
46 return ! (i1->loop == i2->loop && i1->cls == i2->cls);
50 * Compute the highest register pressure in a block.
51 * @param loop_ana The loop ana object.
52 * @param block The block to compute pressure for.
53 * @param cls The register class to compute pressure for.
54 * @return The highest register pressure in the given block.
56 static unsigned be_compute_block_pressure(be_loopana_t *loop_ana, ir_node *block, const arch_register_class_t *cls) {
57 const arch_env_t *aenv = loop_ana->birg->main_env->arch_env;
58 pset *live_nodes = pset_new_ptr_default();
62 DBG((dbg, LEVEL_1, "Processing Block %+F\n", block));
64 /* determine largest pressure with this block */
65 live_nodes = be_liveness_end_of_block(loop_ana->birg->lv, aenv, cls, block, live_nodes);
66 max_live = pset_count(live_nodes);
68 sched_foreach_reverse(block, irn) {
74 live_nodes = be_liveness_transfer(aenv, cls, irn, live_nodes);
75 cnt = pset_count(live_nodes);
76 max_live = MAX(cnt, max_live);
79 DBG((dbg, LEVEL_1, "Finished with Block %+F (%s %u)\n", block, cls->name, max_live));
86 * Compute the highest register pressure in a loop and it's sub-loops.
87 * @param loop_ana The loop ana object.
88 * @param loop The loop to compute pressure for.
89 * @param cls The register class to compute pressure for.
90 * @return The highest register pressure in the given loop.
92 static unsigned be_compute_loop_pressure(be_loopana_t *loop_ana, ir_loop *loop, const arch_register_class_t *cls) {
95 be_loop_info_t *entry, key;
97 DBG((dbg, LEVEL_1, "\nProcessing Loop %d\n", loop->loop_nr));
98 assert(get_loop_n_elements(loop) > 0);
101 /* determine maximal pressure in all loop elements */
102 for (i = 0, max = get_loop_n_elements(loop); i < max; ++i) {
103 unsigned son_pressure;
104 loop_element elem = get_loop_element(loop, i);
106 switch (*elem.kind) {
108 son_pressure = be_compute_block_pressure(loop_ana, elem.node, cls);
111 son_pressure = be_compute_loop_pressure(loop_ana, elem.son, cls);
114 panic("Unknown element found in loop");
118 pressure = MAX(pressure, son_pressure);
120 DBG((dbg, LEVEL_1, "Done with loop %d, pressure %u for class %s\n", loop->loop_nr, pressure, cls->name));
122 /* update info in set */
125 key.max_pressure = 0;
126 entry = set_insert(loop_ana->data, &key, sizeof(key), HASH_LOOP_INFO(&key));
127 entry->max_pressure = MAX(entry->max_pressure, pressure);
133 * Compute the register pressure for a class of all loops in the birg.
134 * @param birg The backend irg object
135 * @param cls The register class to compute the pressure for
136 * @return The loop analysis object.
138 be_loopana_t *be_new_loop_pressure_cls(be_irg_t *birg, const arch_register_class_t *cls) {
139 be_loopana_t *loop_ana = xmalloc(sizeof(*loop_ana));
141 loop_ana->data = new_set(cmp_loop_info, 16);
142 loop_ana->birg = birg;
144 DBG((dbg, LEVEL_1, "\n=====================================================\n", cls->name));
145 DBG((dbg, LEVEL_1, " Computing register pressure for class %s:\n", cls->name));
146 DBG((dbg, LEVEL_1, "=====================================================\n", cls->name));
148 be_compute_loop_pressure(loop_ana, get_irg_loop(birg->irg), cls);
154 * Compute the register pressure for all classes of all loops in the birg.
155 * @param birg The backend irg object
156 * @return The loop analysis object.
158 be_loopana_t *be_new_loop_pressure(be_irg_t *birg) {
159 be_loopana_t *loop_ana = xmalloc(sizeof(*loop_ana));
160 ir_loop *irg_loop = get_irg_loop(birg->irg);
163 loop_ana->data = new_set(cmp_loop_info, 16);
164 loop_ana->birg = birg;
166 for (i = arch_isa_get_n_reg_class(birg->main_env->arch_env->isa) - 1; i >= 0; --i) {
167 const arch_register_class_t *cls = arch_isa_get_reg_class(birg->main_env->arch_env->isa, i);
168 DBG((dbg, LEVEL_1, "\n=====================================================\n", cls->name));
169 DBG((dbg, LEVEL_1, " Computing register pressure for class %s:\n", cls->name));
170 DBG((dbg, LEVEL_1, "=====================================================\n", cls->name));
171 be_compute_loop_pressure(loop_ana, irg_loop, cls);
178 * Returns the computed register pressure for the given class and loop.
179 * @return The pressure or INT_MAX if not found
181 unsigned be_get_loop_pressure(be_loopana_t *loop_ana, const arch_register_class_t *cls, ir_loop *loop) {
182 unsigned pressure = INT_MAX;
183 be_loop_info_t *entry, key;
189 entry = set_find(loop_ana->data, &key, sizeof(key), HASH_LOOP_INFO(&key));
192 pressure = entry->max_pressure;
194 assert(0 && "Pressure not computed for given class and loop object.");
200 * Frees the loop analysis object.
202 void be_free_loop_pressure(be_loopana_t *loop_ana) {
203 del_set(loop_ana->data);
207 void be_init_loopana(void)
209 FIRM_DBG_REGISTER(dbg, "firm.be.loopana");
212 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_loopana);