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"
25 typedef struct _be_loop_info_t {
27 const arch_register_class_t *cls;
28 unsigned max_pressure;
31 struct _be_loopana_t {
34 DEBUG_ONLY(firm_dbg_module_t *dbg);
37 static int cmp_loop_info(const void *a, const void *b, size_t sz) {
38 const be_loop_info_t *i1 = a;
39 const be_loop_info_t *i2 = b;
41 return ! (i1->loop == i2->loop && i1->cls == i2->cls);
45 * Compute the highest register pressure in a block.
46 * @param loop_ana The loop ana object.
47 * @param block The block to compute pressure for.
48 * @param cls The register class to compute pressure for.
49 * @return The highest register pressure in the given block.
51 static unsigned be_compute_block_pressure(be_loopana_t *loop_ana, ir_node *block, const arch_register_class_t *cls) {
52 const arch_env_t *aenv = loop_ana->birg->main_env->arch_env;
53 pset *live_nodes = pset_new_ptr_default();
57 /* determine largest pressure with this block */
58 live_nodes = be_liveness_end_of_block(loop_ana->birg->lv, aenv, cls, block, live_nodes);
59 max_live = pset_count(live_nodes);
61 sched_foreach_reverse(block, irn) {
67 live_nodes = be_liveness_transfer(aenv, cls, irn, live_nodes);
68 cnt = pset_count(live_nodes);
69 max_live = MAX(cnt, max_live);
77 * Compute the highest register pressure in a loop and it's sub-loops.
78 * @param loop_ana The loop ana object.
79 * @param loop The loop to compute pressure for.
80 * @param cls The register class to compute pressure for.
81 * @return The highest register pressure in the given loop.
83 static unsigned be_compute_loop_pressure(be_loopana_t *loop_ana, ir_loop *loop, const arch_register_class_t *cls) {
85 be_loop_info_t *entry, key;
87 DBG((loop_ana->dbg, LEVEL_1, "Processing Loop %d\n", loop->loop_nr));
88 assert(get_loop_n_elements(loop) > 0);
91 /* determine maximal pressure in all loop elements */
92 for (i = 0, max = get_loop_n_elements(loop); i < max; ++i) {
93 loop_element elem = get_loop_element(loop, i);
96 pressure = be_compute_block_pressure(loop_ana, elem.node, cls);
99 unsigned son_pressure = be_compute_loop_pressure(loop_ana, elem.son, cls);
100 pressure = MAX(pressure, son_pressure);
108 DBG((loop_ana->dbg, LEVEL_1, "Done with loop %d, pressure %u for class %s\n", loop->loop_nr, pressure, cls->name));
110 /* update info in set */
114 entry = set_insert(loop_ana->data, &key, sizeof(key), HASH_PTR(loop));
115 entry->max_pressure = MAX(entry->max_pressure, pressure);
121 * Compute the register pressure for a class of all loops in the birg.
122 * @param birg The backend irg object
123 * @param cls The register class to compute the pressure for
124 * @return The loop analysation object.
126 be_loopana_t *be_new_loop_pressure_cls(be_irg_t *birg, const arch_register_class_t *cls) {
127 be_loopana_t *loop_ana = xmalloc(sizeof(loop_ana));
129 loop_ana->data = new_set(cmp_loop_info, 16);
130 loop_ana->birg = birg;
131 FIRM_DBG_REGISTER(loop_ana->dbg, "firm.be.loopana");
133 be_compute_loop_pressure(loop_ana, get_irg_loop(birg->irg), cls);
139 * Compute the register pressure for all classes of all loops in the birg.
140 * @param birg The backend irg object
141 * @return The loop analysation object.
143 be_loopana_t *be_new_loop_pressure(be_irg_t *birg) {
144 be_loopana_t *loop_ana = xmalloc(sizeof(loop_ana));
145 ir_loop *irg_loop = get_irg_loop(birg->irg);
148 loop_ana->data = new_set(cmp_loop_info, 16);
149 loop_ana->birg = birg;
150 FIRM_DBG_REGISTER(loop_ana->dbg, "firm.be.loopana");
152 for (i = arch_isa_get_n_reg_class(birg->main_env->arch_env->isa) - 1; i >= 0; --i) {
153 const arch_register_class_t *cls = arch_isa_get_reg_class(birg->main_env->arch_env->isa, i);
154 be_compute_loop_pressure(loop_ana, irg_loop, cls);
161 * Returns the computed register pressure for the given class and loop.
162 * @return The pressure or INT_MAX if not found
164 unsigned be_get_loop_pressure(be_loopana_t *loop_ana, const arch_register_class_t *cls, ir_loop *loop) {
165 unsigned pressure = INT_MAX;
166 be_loop_info_t *entry, key;
172 entry = set_find(loop_ana->data, &key, sizeof(key), HASH_PTR(&key));
175 pressure = entry->max_pressure;
177 assert(0 && "Pressure not computed for given class and loop object.");
183 * Frees loop analysation object.
185 void be_free_loop_pressure(be_loopana_t *loop_ana) {
186 del_set(loop_ana->data);