2 * Author: Matthias Braun
4 * Copyright: (c) Universitaet Karlsruhe
5 * License: This file is protected by GPL - GNU GENERAL PUBLIC LICENSE.
12 #include "bespillmorgan.h"
14 #include "bechordal_t.h"
22 #include "irgraph_t.h"
26 #include "bespillbelady.h"
28 #include "benodesets.h"
32 #define DBG_PRESSURE 4
35 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
37 typedef struct morgan_env {
38 const be_chordal_env_t *cenv;
39 const arch_env_t *arch;
40 const arch_register_class_t *cls;
43 /** maximum safe register pressure */
44 int registers_available;
52 typedef struct loop_edge {
57 typedef struct loop_attr {
61 /** The set of all values that are live in the loop but not used in the loop */
62 bitset_t *livethrough_unused;
65 typedef struct block_attr {
67 /** set of all values that are live in the block but not used in the block */
68 bitset_t *livethrough_unused;
71 //---------------------------------------------------------------------------
73 static int loop_edge_cmp(const void* p1, const void* p2, size_t s) {
74 loop_edge_t *e1 = (loop_edge_t*) p1;
75 loop_edge_t *e2 = (loop_edge_t*) p2;
77 return e1->block != e2->block || e1->pos != e2->pos;
80 static int loop_attr_cmp(const void *e1, const void *e2, size_t s) {
81 loop_attr_t *la1 = (loop_attr_t*) e1;
82 loop_attr_t *la2 = (loop_attr_t*) e2;
84 return la1->loop != la2->loop;
87 static int block_attr_cmp(const void *e1, const void *e2, size_t s) {
88 block_attr_t *b1 = (block_attr_t*) e1;
89 block_attr_t *b2 = (block_attr_t*) e2;
91 return b1->block != b2->block;
94 static INLINE int loop_attr_hash(const loop_attr_t *a) {
96 return a->loop->loop_nr;
98 return HASH_PTR(a->loop);
102 static INLINE int block_attr_hash(const block_attr_t *b) {
103 return nodeset_hash(b->block);
106 static INLINE int loop_edge_hash(const loop_edge_t *e) {
107 return nodeset_hash(e->block) ^ (e->pos * 31);
110 static INLINE loop_attr_t *get_loop_attr(morgan_env_t *env, const ir_loop *loop) {
111 loop_attr_t l_attr, *res;
115 hash = loop_attr_hash(&l_attr);
116 res = set_find(env->loop_attr_set, &l_attr, sizeof(l_attr), hash);
118 // create new loop_attr if none exists yet
120 l_attr.out_edges = new_set(loop_edge_cmp, 1);
121 l_attr.in_edges = new_set(loop_edge_cmp, 1);
122 l_attr.livethrough_unused = bitset_obstack_alloc(&env->obst, get_irg_last_idx(env->irg));
123 res = set_insert(env->loop_attr_set, &l_attr, sizeof(l_attr), hash);
129 static INLINE block_attr_t *get_block_attr(morgan_env_t *env, const ir_node *block) {
130 block_attr_t b_attr, *res;
132 b_attr.block = block;
134 hash = block_attr_hash(&b_attr);
135 res = set_find(env->block_attr_set, &b_attr, sizeof(b_attr), hash);
138 b_attr.livethrough_unused = NULL;
139 res = set_insert(env->block_attr_set, &b_attr, sizeof(b_attr), hash);
145 //---------------------------------------------------------------------------
147 static INLINE int consider_for_spilling(const arch_env_t *env, const arch_register_class_t *cls, const ir_node *node) {
148 if(!arch_irn_has_reg_class(env, node, -1, cls))
151 return !(arch_irn_get_flags(env, node) & (arch_irn_flags_ignore | arch_irn_flags_dont_spill));
155 * Determine edges going out of a loop (= edges that go to a block that is not
156 * inside the loop or one of its subloops)
158 static INLINE void construct_loop_edges(ir_node *block, void *data) {
159 morgan_env_t *env = data;
160 int n_cfgpreds = get_Block_n_cfgpreds(block);
162 ir_loop* loop = get_irn_loop(block);
163 DBG((dbg, DBG_LOOPANA, "Loop for %+F: %d (depth %d)\n", block, loop->loop_nr, loop->depth));
165 for(i = 0; i < n_cfgpreds; ++i) {
168 ir_node* cfgpred = get_Block_cfgpred(block, i);
169 ir_node* cfgpred_block = get_nodes_block(cfgpred);
170 ir_loop* cfgpred_loop = get_irn_loop(cfgpred_block);
172 if(cfgpred_loop == loop)
175 assert(get_loop_depth(cfgpred_loop) != get_loop_depth(loop));
179 hash = loop_edge_hash(&edge);
181 // edge out of a loop?
182 if(get_loop_depth(cfgpred_loop) > get_loop_depth(loop)) {
185 DBG((dbg, DBG_LOOPANA, "Loop out edge from %+F (loop %d) to %+F (loop %d)\n", block, get_loop_loop_nr(loop),
186 cfgpred_block, get_loop_loop_nr(cfgpred_loop)));
188 /* this might be a jump out of multiple loops, so add this to all
189 * needed outedge sets */
192 loop_attr_t *l_attr = get_loop_attr(env, l);
193 set_insert(l_attr->out_edges, &edge, sizeof(edge), hash);
195 l = get_loop_outer_loop(l);
202 DBG((dbg, DBG_LOOPANA, "Loop in edge from %+F (loop %d) to %+F (loop %d)\n", block, get_loop_loop_nr(loop),
203 cfgpred_block, get_loop_loop_nr(cfgpred_loop)));
207 loop_attr_t *l_attr = get_loop_attr(env, l);
208 set_insert(l_attr->in_edges, &edge, sizeof(edge), hash);
210 l = get_loop_outer_loop(l);
211 } while(l != cfgpred_loop);
216 static void free_loop_edges(morgan_env_t *env) {
219 for(l_attr = set_first(env->loop_attr_set); l_attr != NULL; l_attr = set_next(env->loop_attr_set)) {
220 del_set(l_attr->out_edges);
221 del_set(l_attr->in_edges);
227 * Debugging help, shows all nodes in a (node-)bitset
229 static void show_nodebitset(ir_graph* irg, const bitset_t* bitset) {
232 bitset_foreach(bitset, i) {
233 ir_node* node = get_idx_irn(irg, i);
234 ir_fprintf(stderr, " %+F", node);
236 fprintf(stderr, "\n");
240 static INLINE void init_livethrough_unuseds(block_attr_t *attr, morgan_env_t *env) {
241 const ir_node *block;
243 be_lv_t *lv = env->cenv->birg->lv;
245 if(attr->livethrough_unused != NULL)
250 attr->livethrough_unused = bitset_obstack_alloc(&env->obst, get_irg_last_idx(env->irg));
252 // copy all live-outs into the livethrough_unused set
253 be_lv_foreach(lv, block, be_lv_state_in | be_lv_state_out, i) {
254 ir_node *irn = be_lv_get_irn(lv, block, i);
257 if(!consider_for_spilling(env->arch, env->cls, irn))
260 node_idx = get_irn_idx(irn);
261 bitset_set(attr->livethrough_unused, node_idx);
266 * Construct the livethrough unused set for a block
268 static void construct_block_livethrough_unused(ir_node *block, void *data) {
269 morgan_env_t* env = data;
270 block_attr_t *block_attr = get_block_attr(env, block);
273 block_attr_t **pred_attrs = NULL;
276 init_livethrough_unuseds(block_attr, env);
278 DBG((dbg, DBG_LIVE, "Processing block %d\n", get_irn_node_nr(block)));
280 n_cfgpreds = get_Block_n_cfgpreds(block);
282 pred_attrs = alloca(sizeof(pred_attrs[0]) * n_cfgpreds);
283 for(i = 0; i < n_cfgpreds; ++i) {
284 ir_node *pred_block = get_Block_cfgpred_block(block, i);
285 pred_attrs[i] = get_block_attr(env, pred_block);
286 init_livethrough_unuseds(pred_attrs[i], env);
291 * All values that are used within the block are not unused (and therefore not
292 * livethrough_unused)
294 sched_foreach(block, node) {
297 // phis are really uses in the pred block
300 for(j = 0; j < n_cfgpreds; ++j) {
301 ir_node *used_value = get_Phi_pred(node, j);
302 int idx = get_irn_idx(used_value);
303 block_attr_t *pred_attr = pred_attrs[j];
305 bitset_clear(pred_attr->livethrough_unused, idx);
308 // mark all used values as used
309 for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
310 int idx = get_irn_idx(get_irn_n(node, i));
311 bitset_clear(block_attr->livethrough_unused, idx);
318 * Construct the livethrough unused set for a loop (and all its subloops+blocks)
320 static bitset_t *construct_loop_livethrough_unused(morgan_env_t *env, const ir_loop *loop) {
322 loop_attr_t* loop_attr = get_loop_attr(env, loop);
324 DBG((dbg, DBG_LIVE, "Processing Loop %d\n", loop->loop_nr));
325 assert(get_loop_n_elements(loop) > 0);
326 for(i = 0; i < get_loop_n_elements(loop); ++i) {
327 loop_element elem = get_loop_element(loop, i);
328 switch (*elem.kind) {
330 ir_node *block = elem.node;
331 block_attr_t *block_attr = get_block_attr(env, block);
332 bitset_t *livethrough_block_unused = block_attr->livethrough_unused;
334 assert(is_Block(elem.node));
335 assert(livethrough_block_unused != NULL);
338 bitset_copy(loop_attr->livethrough_unused, livethrough_block_unused);
340 bitset_and(loop_attr->livethrough_unused, livethrough_block_unused);
345 bitset_t *livethrough_son_unused;
347 livethrough_son_unused = construct_loop_livethrough_unused(env, elem.son);
349 bitset_copy(loop_attr->livethrough_unused, livethrough_son_unused);
351 bitset_and(loop_attr->livethrough_unused, livethrough_son_unused);
360 DBG((dbg, DBG_LIVE, "Done with loop %d\n", loop->loop_nr));
362 // remove all unused livethroughs that are remembered for this loop from child loops and blocks
363 for(i = 0; i < get_loop_n_elements(loop); ++i) {
364 const loop_element elem = get_loop_element(loop, i);
366 if(*elem.kind == k_ir_loop) {
367 loop_attr_t *son_attr = get_loop_attr(env, elem.son);
368 bitset_andnot(son_attr->livethrough_unused, loop_attr->livethrough_unused);
370 DBG((dbg, DBG_LIVE, "Livethroughs for loop %d:\n", loop->loop_nr));
371 } else if(*elem.kind == k_ir_node) {
372 block_attr_t *block_attr = get_block_attr(env, elem.node);
373 bitset_andnot(block_attr->livethrough_unused, loop_attr->livethrough_unused);
375 DBG((dbg, DBG_LIVE, "Livethroughs for block %+F\n", elem.node));
381 return loop_attr->livethrough_unused;
384 /*---------------------------------------------------------------------------*/
386 typedef struct _spillcandidate_t {
391 static int compare_spillcandidates(const void *d1, const void *d2) {
392 const spillcandidate_t *cand1 = d1;
393 const spillcandidate_t *cand2 = d2;
395 return cand1->cost - cand2->cost;
398 static void spill_values(morgan_env_t *env, const loop_attr_t *loop_attr, int spills) {
399 const bitset_t *cand_bitset = loop_attr->livethrough_unused;
400 int candidatecount = bitset_popcnt(cand_bitset);
401 spillcandidate_t *candidates;
405 assert(spills <= candidatecount);
407 candidates = alloca(sizeof(candidates[0]) * candidatecount);
409 DBG((dbg, DBG_CHOOSE, "Candidates for loop %d\n", get_loop_loop_nr(loop_attr->loop)));
410 // build candidiatelist
412 bitset_foreach(cand_bitset, i) {
413 ir_node *node = get_idx_irn(env->irg, i);
414 candidates[c].node = node;
415 candidates[c].cost = 0;
417 for(edge = set_first(loop_attr->out_edges); edge != NULL; edge = set_next(loop_attr->out_edges)) {
418 candidates[c].cost += be_get_reload_costs_on_edge(env->senv, node, edge->block, edge->pos);
420 DBG((dbg, DBG_CHOOSE, "%+F has costs %d\n", node, candidates[c].cost));
424 assert(c == candidatecount);
427 qsort(candidates, candidatecount, sizeof(candidates[0]), compare_spillcandidates);
430 for(i = 0; i < spills; ++i) {
431 ir_node *to_spill = candidates[i].node;
432 DBG((dbg, DBG_CHOOSE, "Spilling %+F ", to_spill));
434 for(edge = set_first(loop_attr->out_edges); edge != NULL; edge = set_next(loop_attr->out_edges)) {
435 be_add_reload_on_edge(env->senv, to_spill, edge->block, edge->pos);
440 static int reduce_register_pressure_in_block(morgan_env_t *env, const ir_node* block, int loop_unused_spills_possible) {
443 int loop_unused_spills_needed;
444 pset *live_nodes = pset_new_ptr_default();
445 be_lv_t *lv = env->cenv->birg->lv;
447 be_liveness_end_of_block(lv, env->arch, env->cls, block, live_nodes);
448 max_pressure = pset_count(live_nodes);
450 DBG((dbg, DBG_LIVE, "Reduce pressure to %d In Block %+F:\n", env->registers_available, block));
453 * Determine register pressure in block
455 sched_foreach_reverse(block, node) {
461 be_liveness_transfer(env->arch, env->cls, node, live_nodes);
462 pressure = pset_count(live_nodes);
463 if(pressure > max_pressure)
464 max_pressure = pressure;
466 del_pset(live_nodes);
468 loop_unused_spills_needed = max_pressure - env->registers_available;
470 if(loop_unused_spills_needed < 0) {
471 loop_unused_spills_needed = 0;
472 } else if(loop_unused_spills_needed > loop_unused_spills_possible) {
473 loop_unused_spills_needed = loop_unused_spills_possible;
476 DBG((dbg, DBG_PRESSURE, "Block %+F: max-pressure %d spills possible: %d spills used: %d\n",
477 block, max_pressure, loop_unused_spills_possible, loop_unused_spills_needed));
478 return loop_unused_spills_needed;
482 * Reduce register pressure in a loop
484 * @param unused_spills_possible Number of spills from livethrough_unused variables possible in outer loops
485 * @return Number of spills of livethrough_unused variables needed in outer loops
487 static int reduce_register_pressure_in_loop(morgan_env_t *env, const ir_loop *loop, int outer_spills_possible) {
489 loop_attr_t* loop_attr = get_loop_attr(env, loop);
490 int spills_needed = 0;
491 int spills_possible = outer_spills_possible + bitset_popcnt(loop_attr->livethrough_unused);
492 int outer_spills_needed;
494 DBG((dbg, DBG_PRESSURE, "Reducing Pressure in loop %d\n", loop->loop_nr));
495 for(i = 0; i < get_loop_n_elements(loop); ++i) {
496 loop_element elem = get_loop_element(loop, i);
497 switch (*elem.kind) {
500 assert(is_Block(elem.node));
501 needed = reduce_register_pressure_in_block(env, elem.node, spills_possible);
503 assert(needed <= spills_possible);
504 if(needed > spills_needed)
505 spills_needed = needed;
509 int needed = reduce_register_pressure_in_loop(env, elem.son, spills_possible);
511 assert(needed <= spills_possible);
512 if(needed > spills_needed)
513 spills_needed = needed;
522 /* calculate number of spills needed in outer loop and spill
523 * unused livethrough nodes around this loop */
524 if(spills_needed > outer_spills_possible) {
526 outer_spills_needed = outer_spills_possible;
527 spills_needed -= outer_spills_possible;
529 spills_to_place = spills_needed;
531 DBG((dbg, DBG_SPILLS, "%d values unused in loop %d, spilling %d\n",
532 spills_possible - outer_spills_possible, loop->loop_nr, spills_to_place));
534 spill_values(env, loop_attr, spills_to_place);
536 outer_spills_needed = spills_needed;
539 return outer_spills_needed;
542 void be_spill_morgan(be_chordal_env_t *chordal_env) {
543 ir_graph *irg = chordal_env->irg;
546 FIRM_DBG_REGISTER(dbg, "ir.be.spillmorgan");
547 //firm_dbg_set_mask(dbg, DBG_SPILLS | DBG_LOOPANA);
549 env.cenv = chordal_env;
550 env.arch = chordal_env->birg->main_env->arch_env;
551 env.irg = chordal_env->irg;
552 env.cls = chordal_env->cls;
553 env.senv = be_new_spill_env(chordal_env);
554 DEBUG_ONLY(be_set_spill_env_dbg_module(env.senv, dbg);)
556 obstack_init(&env.obst);
558 env.registers_available = env.cls->n_regs - be_put_ignore_regs(chordal_env->birg, env.cls, NULL);
560 env.loop_attr_set = new_set(loop_attr_cmp, 5);
561 env.block_attr_set = new_set(block_attr_cmp, 20);
563 /*-- Part1: Analysis --*/
564 //Matze: I hope liveness information is up to date at this point...
565 //be_liveness_recompute(chordal_env->lv);
567 /* construct control flow loop tree */
568 if(! (get_irg_loopinfo_state(irg) & loopinfo_cf_consistent)) {
569 construct_cf_backedges(irg);
572 /* construct loop out edges and livethrough_unused sets for loops and blocks */
573 irg_block_walk_graph(irg, construct_block_livethrough_unused, construct_loop_edges, &env);
574 construct_loop_livethrough_unused(&env, get_irg_loop(irg));
576 /*-- Part2: Transformation --*/
578 /* spill unused livethrough values around loops and blocks where
579 * the pressure is too high
581 reduce_register_pressure_in_loop(&env, get_irg_loop(irg), 0);
583 /* Insert real spill/reload nodes and fix usages */
584 be_insert_spills_reloads(env.senv);
586 /* Verify the result */
587 if (chordal_env->opts->vrfy_option == BE_CH_VRFY_WARN) {
588 be_verify_schedule(irg);
589 } else if (chordal_env->opts->vrfy_option == BE_CH_VRFY_ASSERT) {
590 assert(be_verify_schedule(irg));
593 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SPILL)
594 be_dump(irg, "-spillmorgan", dump_ir_block_graph_sched);
597 free_loop_edges(&env);
598 del_set(env.loop_attr_set);
599 del_set(env.block_attr_set);
601 /* fix the remaining places with too high register pressure with beladies algorithm */
602 be_spill_belady_spill_env(chordal_env, env.senv);
604 be_delete_spill_env(env.senv);
605 obstack_free(&env.obst, NULL);