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"
31 #define DBG_PRESSURE 4
32 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
34 typedef struct morgan_env {
35 const be_chordal_env_t *cenv;
36 const arch_env_t *arch;
37 const arch_register_class_t *cls;
40 /** maximum safe register pressure */
41 int registers_available;
49 typedef struct loop_edge {
54 typedef struct loop_attr {
58 /** The set of all values that are live in the loop but not used in the loop */
59 bitset_t *livethrough_unused;
62 typedef struct block_attr {
64 /** set of all values that are live in the block but not used in the block */
65 bitset_t *livethrough_unused;
68 //---------------------------------------------------------------------------
70 static int loop_edge_cmp(const void* p1, const void* p2, size_t s) {
71 loop_edge_t *e1 = (loop_edge_t*) p1;
72 loop_edge_t *e2 = (loop_edge_t*) p2;
74 return e1->block != e2->block || e1->pos != e2->pos;
77 static int loop_attr_cmp(const void *e1, const void *e2, size_t s) {
78 loop_attr_t *la1 = (loop_attr_t*) e1;
79 loop_attr_t *la2 = (loop_attr_t*) e2;
81 return la1->loop != la2->loop;
84 static int block_attr_cmp(const void *e1, const void *e2, size_t s) {
85 block_attr_t *b1 = (block_attr_t*) e1;
86 block_attr_t *b2 = (block_attr_t*) e2;
88 return b1->block != b2->block;
91 static INLINE int loop_attr_hash(const loop_attr_t *a) {
92 return HASH_PTR(a->loop);
95 static INLINE int block_attr_hash(const block_attr_t *b) {
96 return HASH_PTR(b->block);
99 static INLINE int loop_edge_hash(const loop_edge_t *e) {
100 return HASH_PTR(e->block) ^ (e->pos * 31);
103 static INLINE loop_attr_t *get_loop_attr(morgan_env_t *env, const ir_loop *loop) {
104 loop_attr_t l_attr, *res;
108 hash = loop_attr_hash(&l_attr);
109 res = set_find(env->loop_attr_set, &l_attr, sizeof(l_attr), hash);
111 // create new loop_attr if none exists yet
113 l_attr.out_edges = new_set(loop_edge_cmp, 1);
114 l_attr.in_edges = new_set(loop_edge_cmp, 1);
115 l_attr.livethrough_unused = bitset_obstack_alloc(&env->obst, get_irg_last_idx(env->irg));
116 res = set_insert(env->loop_attr_set, &l_attr, sizeof(l_attr), hash);
122 static INLINE block_attr_t *get_block_attr(morgan_env_t *env, const ir_node *block) {
123 block_attr_t b_attr, *res;
125 b_attr.block = block;
127 hash = block_attr_hash(&b_attr);
128 res = set_find(env->block_attr_set, &b_attr, sizeof(b_attr), hash);
131 b_attr.livethrough_unused = bitset_obstack_alloc(&env->obst, get_irg_last_idx(env->irg));
132 res = set_insert(env->block_attr_set, &b_attr, sizeof(b_attr), hash);
138 //---------------------------------------------------------------------------
140 static INLINE int consider_for_spilling(const arch_env_t *env, const arch_register_class_t *cls, const ir_node *node) {
141 if(!arch_irn_has_reg_class(env, node, -1, cls))
144 return !(arch_irn_get_flags(env, node) & (arch_irn_flags_ignore | arch_irn_flags_dont_spill));
148 * Determine edges going out of a loop (= edges that go to a block that is not inside
149 * the loop or one of its subloops)
151 static INLINE void construct_loop_edges(ir_node* block, void* e) {
152 morgan_env_t *env = (morgan_env_t*) e;
153 int n_cfgpreds = get_Block_n_cfgpreds(block);
155 ir_loop* loop = get_irn_loop(block);
156 loop_attr_t *loop_attr = get_loop_attr(env, loop);
157 DBG((dbg, DBG_LOOPANA, "Loop for %+F: %d (depth %d)\n", block, loop->loop_nr, loop->depth));
159 for(i = 0; i < n_cfgpreds; ++i) {
160 ir_node* cfgpred = get_Block_cfgpred(block, i);
161 ir_node* cfgpred_block = get_nodes_block(cfgpred);
162 ir_loop* cfgpred_loop = get_irn_loop(cfgpred_block);
163 loop_attr_t *outedges = get_loop_attr(env, cfgpred_loop);
165 if(cfgpred_loop == loop)
168 // is it an edge into the loop?
169 if(get_loop_depth(loop) > get_loop_depth(cfgpred_loop)) {
173 DBG((dbg, DBG_LOOPANA, "Loop in edge from %+F (loop %d) to %+F (loop %d)\n", cfgpred_block, get_loop_loop_nr(cfgpred_loop), block, get_loop_loop_nr(loop)));
174 set_insert(loop_attr->in_edges, &edge, sizeof(edge), loop_edge_hash(&edge));
176 ir_loop *p_loop = cfgpred_loop;
177 while(get_loop_depth(p_loop) > get_loop_depth(loop)) {
178 p_loop = get_loop_outer_loop(p_loop);
184 DBG((dbg, DBG_LOOPANA, "Loop in edge from %+F (loop %d) to %+F (loop %d)\n", cfgpred_block, get_loop_loop_nr(cfgpred_loop), block, get_loop_loop_nr(loop)));
185 set_insert(loop_attr->in_edges, &edge, sizeof(edge), loop_edge_hash(&edge));
189 // an edge out of the loop?
190 if(get_loop_depth(cfgpred_loop) >= get_loop_depth(loop)) {
194 DBG((dbg, DBG_LOOPANA, "Loop out edge from %+F (loop %d) to %+F\n", cfgpred_block, cfgpred_loop->loop_nr, block));
195 set_insert(outedges->out_edges, &edge, sizeof(edge), loop_edge_hash(&edge));
197 ir_loop *o_loop = loop;
199 // we might jump in the middle of another inner loop which is not inside
200 // our loop (happens for irreducible graphs). This would be a
201 // real out edge then.
202 while(get_loop_depth(o_loop) > get_loop_depth(cfgpred_loop)) {
203 o_loop = get_loop_outer_loop(o_loop);
206 if(cfgpred_loop != o_loop) {
210 DBG((dbg, DBG_LOOPANA, "Loop out edge from %+F (loop %d) to %+F (into jump)\n", cfgpred_block, cfgpred_loop->loop_nr, block));
211 set_insert(outedges->out_edges, &edge, sizeof(edge), loop_edge_hash(&edge));
217 static void free_loop_edges(morgan_env_t *env) {
220 for(l_attr = set_first(env->loop_attr_set); l_attr != NULL; l_attr = set_next(env->loop_attr_set)) {
221 del_set(l_attr->out_edges);
222 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 DBG((dbg, DBG_LIVE, "\t%+F\n", node));
239 * Construct the livethrough unused set for a block
241 static bitset_t *construct_block_livethrough_unused(morgan_env_t* env, const ir_node* block) {
242 block_attr_t *block_attr = get_block_attr(env, block);
246 DBG((dbg, DBG_LIVE, "Processing block %d\n", get_irn_node_nr(block)));
247 // copy all live-outs into the livethrough_unused set
248 be_lv_foreach(env->cenv->lv, block, be_lv_state_in | be_lv_state_out, i) {
249 ir_node *irn = be_lv_get_irn(env->cenv->lv, block, i);
252 if(!consider_for_spilling(env->arch, env->cls, irn))
255 node_idx = get_irn_idx(irn);
256 bitset_set(block_attr->livethrough_unused, node_idx);
260 * All values that are used within the block are not unused (and therefore not
261 * livethrough_unused)
263 sched_foreach(block, node) {
266 for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
267 int idx = get_irn_idx(get_irn_n(node, i));
268 bitset_clear(block_attr->livethrough_unused, idx);
272 show_nodebitset(env->irg, block_attr->livethrough_unused);
273 return block_attr->livethrough_unused;
277 * Construct the livethrough unused set for a loop (and all its subloops+blocks)
279 static bitset_t *construct_loop_livethrough_unused(morgan_env_t *env, const ir_loop *loop) {
281 loop_attr_t* loop_attr = get_loop_attr(env, loop);
283 DBG((dbg, DBG_LIVE, "Processing Loop %d\n", loop->loop_nr));
284 assert(get_loop_n_elements(loop) > 0);
285 for(i = 0; i < get_loop_n_elements(loop); ++i) {
286 loop_element elem = get_loop_element(loop, i);
287 switch (*elem.kind) {
289 bitset_t *livethrough_block_unused;
290 assert(is_Block(elem.node));
291 livethrough_block_unused = construct_block_livethrough_unused(env, elem.node);
293 bitset_copy(loop_attr->livethrough_unused, livethrough_block_unused);
295 bitset_and(loop_attr->livethrough_unused, livethrough_block_unused);
300 bitset_t *livethrough_son_unused;
302 livethrough_son_unused = construct_loop_livethrough_unused(env, elem.son);
304 bitset_copy(loop_attr->livethrough_unused, livethrough_son_unused);
306 bitset_and(loop_attr->livethrough_unused, livethrough_son_unused);
315 DBG((dbg, DBG_LIVE, "Done with loop %d\n", loop->loop_nr));
317 // remove all unused livethroughs that are remembered for this loop from child loops and blocks
318 for(i = 0; i < get_loop_n_elements(loop); ++i) {
319 const loop_element elem = get_loop_element(loop, i);
321 if(*elem.kind == k_ir_loop) {
322 loop_attr_t *son_attr = get_loop_attr(env, elem.son);
323 bitset_andnot(son_attr->livethrough_unused, loop_attr->livethrough_unused);
325 DBG((dbg, DBG_LIVE, "Livethroughs for loop %d:\n", loop->loop_nr));
326 show_nodebitset(env->irg, son_attr->livethrough_unused);
327 } else if(*elem.kind == k_ir_node) {
328 block_attr_t *block_attr = get_block_attr(env, elem.node);
329 bitset_andnot(block_attr->livethrough_unused, loop_attr->livethrough_unused);
331 DBG((dbg, DBG_LIVE, "Livethroughs for block %+F\n", elem.node));
332 show_nodebitset(env->irg, block_attr->livethrough_unused);
338 return loop_attr->livethrough_unused;
341 /*---------------------------------------------------------------------------*/
343 static int reduce_register_pressure_in_block(morgan_env_t *env, const ir_node* block, int loop_unused_spills_possible) {
346 int loop_unused_spills_needed;
347 pset *live_nodes = pset_new_ptr_default();
349 be_liveness_end_of_block(env->cenv->lv, env->arch, env->cls, block, live_nodes);
350 max_pressure = pset_count(live_nodes);
352 DBG((dbg, DBG_LIVE, "Reduce pressure to %d In Block %+F:\n", env->registers_available, block));
355 * Determine register pressure in block
357 sched_foreach_reverse(block, node) {
363 be_liveness_transfer(env->arch, env->cls, node, live_nodes);
364 pressure = pset_count(live_nodes);
365 if(pressure > max_pressure)
366 max_pressure = pressure;
368 del_pset(live_nodes);
370 DBG((dbg, DBG_PRESSURE, "\tMax Pressure in %+F: %d\n", block, max_pressure));
372 loop_unused_spills_needed = max_pressure - env->registers_available;
374 if(loop_unused_spills_needed < 0) {
375 loop_unused_spills_needed = 0;
376 } else if(loop_unused_spills_needed > loop_unused_spills_possible) {
377 loop_unused_spills_needed = loop_unused_spills_possible;
380 DBG((dbg, DBG_PRESSURE, "Unused spills for Block %+F needed: %d\n", block, loop_unused_spills_needed));
381 return loop_unused_spills_needed;
385 * Reduce register pressure in a loop
387 * @param unused_spills_possible Number of spills from livethrough_unused variables possible in outer loops
388 * @return Number of spills of livethrough_unused variables needed in outer loops
390 static int reduce_register_pressure_in_loop(morgan_env_t *env, const ir_loop *loop, int outer_spills_possible) {
392 loop_attr_t* loop_attr = get_loop_attr(env, loop);
393 int spills_needed = 0;
394 int spills_possible = outer_spills_possible + bitset_popcnt(loop_attr->livethrough_unused);
395 int outer_spills_needed;
397 DBG((dbg, DBG_PRESSURE, "Reducing Pressure in loop %d\n", loop->loop_nr));
398 for(i = 0; i < get_loop_n_elements(loop); ++i) {
399 loop_element elem = get_loop_element(loop, i);
400 switch (*elem.kind) {
403 assert(is_Block(elem.node));
404 needed = reduce_register_pressure_in_block(env, elem.node, spills_possible);
406 assert(needed <= spills_possible);
407 if(needed > spills_needed)
408 spills_needed = needed;
412 int needed = reduce_register_pressure_in_loop(env, elem.son, spills_possible);
414 assert(needed <= spills_possible);
415 if(needed > spills_needed)
416 spills_needed = needed;
425 /* calculate number of spills needed in outer loop and spill
426 * unused livethrough nodes around this loop
428 if(spills_needed > outer_spills_possible) {
430 outer_spills_needed = outer_spills_possible;
431 spills_needed -= outer_spills_possible;
433 spills_to_place = spills_needed;
435 bitset_foreach(loop_attr->livethrough_unused, i) {
437 ir_node *to_spill = get_idx_irn(env->irg, i);
439 for(edge = set_first(loop_attr->out_edges); edge != NULL; edge = set_next(loop_attr->out_edges)) {
440 DBG((dbg, DBG_PRESSURE, "Spilling node %+F around loop %d\n", to_spill, loop->loop_nr));
441 be_add_reload_on_edge(env->senv, to_spill, edge->block, edge->pos);
445 if(spills_to_place <= 0) {
450 outer_spills_needed = spills_needed;
453 return outer_spills_needed;
456 void be_spill_morgan(be_chordal_env_t *chordal_env) {
459 FIRM_DBG_REGISTER(dbg, "ir.be.spillmorgan");
460 //firm_dbg_set_mask(dbg, DBG_LOOPANA | DBG_PRESSURE);
462 env.cenv = chordal_env;
463 env.arch = chordal_env->birg->main_env->arch_env;
464 env.irg = chordal_env->irg;
465 env.cls = chordal_env->cls;
466 env.senv = be_new_spill_env(chordal_env);
467 DEBUG_ONLY(be_set_spill_env_dbg_module(env.senv, dbg);)
469 obstack_init(&env.obst);
471 env.registers_available = env.cls->n_regs - be_put_ignore_regs(chordal_env->birg, env.cls, NULL);
473 env.loop_attr_set = new_set(loop_attr_cmp, 5);
474 env.block_attr_set = new_set(block_attr_cmp, 20);
476 /*-- Part1: Analysis --*/
477 be_liveness_recompute(chordal_env->lv);
479 /* construct control flow loop tree */
480 construct_cf_backedges(chordal_env->irg);
482 /* construct loop out edges and livethrough_unused sets for loops and blocks */
483 irg_block_walk_graph(chordal_env->irg, NULL, construct_loop_edges, &env);
484 construct_loop_livethrough_unused(&env, get_irg_loop(env.irg));
486 /*-- Part2: Transformation --*/
488 /* spill unused livethrough values around loops and blocks where
489 * the pressure is too high
491 reduce_register_pressure_in_loop(&env, get_irg_loop(env.irg), 0);
493 /* Insert real spill/reload nodes and fix usages */
494 be_insert_spills_reloads(env.senv);
496 /* Verify the result */
497 if (chordal_env->opts->vrfy_option == BE_CH_VRFY_WARN) {
498 be_verify_schedule(env.irg);
499 } else if (chordal_env->opts->vrfy_option == BE_CH_VRFY_ASSERT) {
500 assert(be_verify_schedule(env.irg));
503 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SPILL)
504 be_dump(env.irg, "-spillmorgan", dump_ir_block_graph_sched);
507 free_loop_edges(&env);
508 del_set(env.loop_attr_set);
509 del_set(env.block_attr_set);
511 /* fix the remaining places with too high register pressure with beladies algorithm */
512 be_spill_belady_spill_env(chordal_env, env.senv);
514 be_delete_spill_env(env.senv);
515 obstack_free(&env.obst, NULL);