2 * This file is part of libFirm.
3 * Copyright (C) 2012 University of Karlsruhe.
8 * @brief Compute register pressure in loops.
9 * @author Christian Wuerdig
26 #include "beloopana.h"
29 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
31 #define HASH_LOOP_INFO(info) (hash_ptr((info)->loop) ^ hash_ptr((info)->cls))
33 typedef struct be_loop_info_t {
35 const arch_register_class_t *cls;
36 unsigned max_pressure;
43 static int cmp_loop_info(const void *a, const void *b, size_t size)
45 const be_loop_info_t *i1 = (const be_loop_info_t*)a;
46 const be_loop_info_t *i2 = (const be_loop_info_t*)b;
49 return ! (i1->loop == i2->loop && i1->cls == i2->cls);
53 * Compute the highest register pressure in a block.
54 * @param block The block to compute pressure for.
55 * @param cls The register class to compute pressure for.
56 * @return The highest register pressure in the given block.
58 static unsigned be_compute_block_pressure(ir_node *const block, arch_register_class_t const *const cls)
60 ir_nodeset_t live_nodes;
63 DBG((dbg, LEVEL_1, "Processing Block %+F\n", block));
65 /* determine largest pressure with this block */
66 ir_nodeset_init(&live_nodes);
67 be_lv_t *const lv = be_get_irg_liveness(get_Block_irg(block));
68 be_liveness_end_of_block(lv, cls, block, &live_nodes);
69 max_live = ir_nodeset_size(&live_nodes);
71 sched_foreach_reverse(block, irn) {
77 be_liveness_transfer(cls, irn, &live_nodes);
78 cnt = ir_nodeset_size(&live_nodes);
79 max_live = MAX(cnt, max_live);
82 DBG((dbg, LEVEL_1, "Finished with Block %+F (%s %zu)\n", block, cls->name, max_live));
84 ir_nodeset_destroy(&live_nodes);
89 * Compute the highest register pressure in a loop and its 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,
96 const arch_register_class_t *cls)
100 be_loop_info_t *entry, key;
102 DBG((dbg, LEVEL_1, "\nProcessing Loop %ld\n", loop->loop_nr));
103 assert(get_loop_n_elements(loop) > 0);
106 /* determine maximal pressure in all loop elements */
107 for (i = 0, max = get_loop_n_elements(loop); i < max; ++i) {
108 unsigned son_pressure;
109 loop_element elem = get_loop_element(loop, i);
111 if (*elem.kind == k_ir_node)
112 son_pressure = be_compute_block_pressure(elem.node, cls);
114 assert(*elem.kind == k_ir_loop);
115 son_pressure = be_compute_loop_pressure(loop_ana, elem.son, cls);
118 pressure = MAX(pressure, son_pressure);
120 DBG((dbg, LEVEL_1, "Done with loop %ld, 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(be_loop_info_t, loop_ana->data, &key, sizeof(key), HASH_LOOP_INFO(&key));
127 entry->max_pressure = MAX(entry->max_pressure, pressure);
132 be_loopana_t *be_new_loop_pressure(ir_graph *const irg, arch_register_class_t const *const cls)
134 be_loopana_t *loop_ana = XMALLOC(be_loopana_t);
136 loop_ana->data = new_set(cmp_loop_info, 16);
138 DBG((dbg, LEVEL_1, "\n=====================================================\n", cls->name));
139 DBG((dbg, LEVEL_1, " Computing register pressure for class %s:\n", cls->name));
140 DBG((dbg, LEVEL_1, "=====================================================\n", cls->name));
142 assure_loopinfo(irg);
144 be_compute_loop_pressure(loop_ana, get_irg_loop(irg), cls);
149 unsigned be_get_loop_pressure(be_loopana_t *loop_ana, const arch_register_class_t *cls, ir_loop *loop)
151 unsigned pressure = INT_MAX;
152 be_loop_info_t *entry, key;
158 entry = set_find(be_loop_info_t, loop_ana->data, &key, sizeof(key), HASH_LOOP_INFO(&key));
161 pressure = entry->max_pressure;
163 panic("Pressure not computed for given class and loop object.");
168 void be_free_loop_pressure(be_loopana_t *loop_ana)
170 del_set(loop_ana->data);
174 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_loopana)
175 void be_init_loopana(void)
177 FIRM_DBG_REGISTER(dbg, "firm.be.loopana");