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
23 #include "beloopana.h"
26 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL);
28 #define HASH_LOOP_INFO(info) (HASH_PTR((info)->loop) ^ HASH_PTR((info)->cls))
30 typedef struct _be_loop_info_t {
32 const arch_register_class_t *cls;
33 unsigned max_pressure;
36 struct _be_loopana_t {
41 static int cmp_loop_info(const void *a, const void *b, size_t sz) {
42 const be_loop_info_t *i1 = a;
43 const be_loop_info_t *i2 = b;
45 return ! (i1->loop == i2->loop && i1->cls == i2->cls);
49 * Compute the highest register pressure in a block.
50 * @param loop_ana The loop ana object.
51 * @param block The block to compute pressure for.
52 * @param cls The register class to compute pressure for.
53 * @return The highest register pressure in the given block.
55 static unsigned be_compute_block_pressure(be_loopana_t *loop_ana, ir_node *block, const arch_register_class_t *cls) {
56 const arch_env_t *aenv = loop_ana->birg->main_env->arch_env;
57 pset *live_nodes = pset_new_ptr_default();
61 DBG((dbg, LEVEL_1, "Processing Block %+F\n", block));
63 /* determine largest pressure with this block */
64 live_nodes = be_liveness_end_of_block(loop_ana->birg->lv, aenv, cls, block, live_nodes);
65 max_live = pset_count(live_nodes);
67 sched_foreach_reverse(block, irn) {
73 live_nodes = be_liveness_transfer(aenv, cls, irn, live_nodes);
74 cnt = pset_count(live_nodes);
75 max_live = MAX(cnt, max_live);
78 DBG((dbg, LEVEL_1, "Finished with Block %+F (%s %u)\n", block, cls->name, max_live));
85 * Compute the highest register pressure in a loop and it's sub-loops.
86 * @param loop_ana The loop ana object.
87 * @param loop The loop to compute pressure for.
88 * @param cls The register class to compute pressure for.
89 * @return The highest register pressure in the given loop.
91 static unsigned be_compute_loop_pressure(be_loopana_t *loop_ana, ir_loop *loop, const arch_register_class_t *cls) {
94 be_loop_info_t *entry, key;
96 DBG((dbg, LEVEL_1, "\nProcessing Loop %d\n", loop->loop_nr));
97 assert(get_loop_n_elements(loop) > 0);
100 /* determine maximal pressure in all loop elements */
101 for (i = 0, max = get_loop_n_elements(loop); i < max; ++i) {
102 unsigned son_pressure;
103 loop_element elem = get_loop_element(loop, i);
105 switch (*elem.kind) {
107 son_pressure = be_compute_block_pressure(loop_ana, elem.node, cls);
110 son_pressure = be_compute_loop_pressure(loop_ana, elem.son, cls);
117 pressure = MAX(pressure, son_pressure);
119 DBG((dbg, LEVEL_1, "Done with loop %d, pressure %u for class %s\n", loop->loop_nr, pressure, cls->name));
121 /* update info in set */
124 key.max_pressure = 0;
125 entry = set_insert(loop_ana->data, &key, sizeof(key), HASH_LOOP_INFO(&key));
126 entry->max_pressure = MAX(entry->max_pressure, pressure);
132 * Compute the register pressure for a class of all loops in the birg.
133 * @param birg The backend irg object
134 * @param cls The register class to compute the pressure for
135 * @return The loop analysis object.
137 be_loopana_t *be_new_loop_pressure_cls(be_irg_t *birg, const arch_register_class_t *cls) {
138 be_loopana_t *loop_ana = xmalloc(sizeof(*loop_ana));
140 loop_ana->data = new_set(cmp_loop_info, 16);
141 loop_ana->birg = birg;
143 DBG((dbg, LEVEL_1, "\n=====================================================\n", cls->name));
144 DBG((dbg, LEVEL_1, " Computing register pressure for class %s:\n", cls->name));
145 DBG((dbg, LEVEL_1, "=====================================================\n", cls->name));
147 be_compute_loop_pressure(loop_ana, get_irg_loop(birg->irg), cls);
153 * Compute the register pressure for all classes of all loops in the birg.
154 * @param birg The backend irg object
155 * @return The loop analysis object.
157 be_loopana_t *be_new_loop_pressure(be_irg_t *birg) {
158 be_loopana_t *loop_ana = xmalloc(sizeof(*loop_ana));
159 ir_loop *irg_loop = get_irg_loop(birg->irg);
162 loop_ana->data = new_set(cmp_loop_info, 16);
163 loop_ana->birg = birg;
165 for (i = arch_isa_get_n_reg_class(birg->main_env->arch_env->isa) - 1; i >= 0; --i) {
166 const arch_register_class_t *cls = arch_isa_get_reg_class(birg->main_env->arch_env->isa, i);
167 DBG((dbg, LEVEL_1, "\n=====================================================\n", cls->name));
168 DBG((dbg, LEVEL_1, " Computing register pressure for class %s:\n", cls->name));
169 DBG((dbg, LEVEL_1, "=====================================================\n", cls->name));
170 be_compute_loop_pressure(loop_ana, irg_loop, cls);
177 * Returns the computed register pressure for the given class and loop.
178 * @return The pressure or INT_MAX if not found
180 unsigned be_get_loop_pressure(be_loopana_t *loop_ana, const arch_register_class_t *cls, ir_loop *loop) {
181 unsigned pressure = INT_MAX;
182 be_loop_info_t *entry, key;
188 entry = set_find(loop_ana->data, &key, sizeof(key), HASH_LOOP_INFO(&key));
191 pressure = entry->max_pressure;
193 assert(0 && "Pressure not computed for given class and loop object.");
199 * Frees the loop analysis object.
201 void be_free_loop_pressure(be_loopana_t *loop_ana) {
202 del_set(loop_ana->data);
206 void be_init_loopana(void)
208 FIRM_DBG_REGISTER(dbg, "firm.be.loopana");
211 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_loopana);