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
25 #include "beloopana.h"
28 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL);
30 #define HASH_LOOP_INFO(info) (HASH_PTR((info)->loop) ^ HASH_PTR((info)->cls))
32 typedef struct _be_loop_info_t {
34 const arch_register_class_t *cls;
35 unsigned max_pressure;
38 struct _be_loopana_t {
43 static int cmp_loop_info(const void *a, const void *b, size_t sz) {
44 const be_loop_info_t *i1 = a;
45 const be_loop_info_t *i2 = b;
47 return ! (i1->loop == i2->loop && i1->cls == i2->cls);
51 * Compute the highest register pressure in a block.
52 * @param loop_ana The loop ana object.
53 * @param block The block to compute pressure for.
54 * @param cls The register class to compute pressure for.
55 * @return The highest register pressure in the given block.
57 static unsigned be_compute_block_pressure(be_loopana_t *loop_ana, ir_node *block, const arch_register_class_t *cls) {
58 const be_irg_t *birg = loop_ana->birg;
59 const arch_env_t *aenv = be_get_birg_arch_env(birg);
60 be_lv_t *lv = be_get_birg_liveness(birg);
61 pset *live_nodes = pset_new_ptr_default();
65 DBG((dbg, LEVEL_1, "Processing Block %+F\n", block));
67 /* determine largest pressure with this block */
68 live_nodes = be_liveness_end_of_block(lv, aenv, cls, block, live_nodes);
69 max_live = pset_count(live_nodes);
71 sched_foreach_reverse(block, irn) {
77 live_nodes = be_liveness_transfer(aenv, cls, irn, live_nodes);
78 cnt = pset_count(live_nodes);
79 max_live = MAX(cnt, max_live);
82 DBG((dbg, LEVEL_1, "Finished with Block %+F (%s %u)\n", block, cls->name, max_live));
89 * Compute the highest register pressure in a loop and it's sub-loops.
90 * @param loop_ana The loop ana object.
91 * @param loop The loop to compute pressure for.
92 * @param cls The register class to compute pressure for.
93 * @return The highest register pressure in the given loop.
95 static unsigned be_compute_loop_pressure(be_loopana_t *loop_ana, ir_loop *loop, const arch_register_class_t *cls) {
98 be_loop_info_t *entry, key;
100 DBG((dbg, LEVEL_1, "\nProcessing Loop %d\n", loop->loop_nr));
101 assert(get_loop_n_elements(loop) > 0);
104 /* determine maximal pressure in all loop elements */
105 for (i = 0, max = get_loop_n_elements(loop); i < max; ++i) {
106 unsigned son_pressure;
107 loop_element elem = get_loop_element(loop, i);
109 switch (*elem.kind) {
111 son_pressure = be_compute_block_pressure(loop_ana, elem.node, cls);
114 son_pressure = be_compute_loop_pressure(loop_ana, elem.son, cls);
117 panic("Unknown element found in loop");
121 pressure = MAX(pressure, son_pressure);
123 DBG((dbg, LEVEL_1, "Done with loop %d, pressure %u for class %s\n", loop->loop_nr, pressure, cls->name));
125 /* update info in set */
128 key.max_pressure = 0;
129 entry = set_insert(loop_ana->data, &key, sizeof(key), HASH_LOOP_INFO(&key));
130 entry->max_pressure = MAX(entry->max_pressure, pressure);
136 * Compute the register pressure for a class of all loops in the birg.
137 * @param birg The backend irg object
138 * @param cls The register class to compute the pressure for
139 * @return The loop analysis object.
141 be_loopana_t *be_new_loop_pressure_cls(be_irg_t *birg,
142 const arch_register_class_t *cls) {
143 ir_graph *irg = be_get_birg_irg(birg);
144 be_loopana_t *loop_ana = xmalloc(sizeof(*loop_ana));
146 loop_ana->data = new_set(cmp_loop_info, 16);
147 loop_ana->birg = birg;
149 DBG((dbg, LEVEL_1, "\n=====================================================\n", cls->name));
150 DBG((dbg, LEVEL_1, " Computing register pressure for class %s:\n", cls->name));
151 DBG((dbg, LEVEL_1, "=====================================================\n", cls->name));
153 be_compute_loop_pressure(loop_ana, get_irg_loop(irg), cls);
159 * Compute the register pressure for all classes of all loops in the birg.
160 * @param birg The backend irg object
161 * @return The loop analysis object.
163 be_loopana_t *be_new_loop_pressure(be_irg_t *birg) {
164 ir_graph *irg = be_get_birg_irg(birg);
165 be_loopana_t *loop_ana = xmalloc(sizeof(*loop_ana));
166 ir_loop *irg_loop = get_irg_loop(irg);
167 const arch_env_t *arch_env = be_get_birg_arch_env(birg);
168 const arch_isa_t *isa = arch_env->isa;
171 loop_ana->data = new_set(cmp_loop_info, 16);
172 loop_ana->birg = birg;
174 for (i = arch_isa_get_n_reg_class(isa) - 1; i >= 0; --i) {
175 const arch_register_class_t *cls = arch_isa_get_reg_class(isa, i);
176 DBG((dbg, LEVEL_1, "\n=====================================================\n", cls->name));
177 DBG((dbg, LEVEL_1, " Computing register pressure for class %s:\n", cls->name));
178 DBG((dbg, LEVEL_1, "=====================================================\n", cls->name));
179 be_compute_loop_pressure(loop_ana, irg_loop, cls);
186 * Returns the computed register pressure for the given class and loop.
187 * @return The pressure or INT_MAX if not found
189 unsigned be_get_loop_pressure(be_loopana_t *loop_ana, const arch_register_class_t *cls, ir_loop *loop) {
190 unsigned pressure = INT_MAX;
191 be_loop_info_t *entry, key;
197 entry = set_find(loop_ana->data, &key, sizeof(key), HASH_LOOP_INFO(&key));
200 pressure = entry->max_pressure;
202 assert(0 && "Pressure not computed for given class and loop object.");
208 * Frees the loop analysis object.
210 void be_free_loop_pressure(be_loopana_t *loop_ana) {
211 del_set(loop_ana->data);
215 void be_init_loopana(void)
217 FIRM_DBG_REGISTER(dbg, "firm.be.loopana");
220 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_loopana);