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
33 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
35 typedef struct morgan_env {
36 const be_chordal_env_t *cenv;
37 const arch_env_t *arch;
38 const arch_register_class_t *cls;
41 /** maximum safe register pressure */
42 int registers_available;
50 typedef struct loop_edge {
55 typedef struct loop_attr {
59 /** The set of all values that are live in the loop but not used in the loop */
60 bitset_t *livethrough_unused;
63 typedef struct block_attr {
65 /** set of all values that are live in the block but not used in the block */
66 bitset_t *livethrough_unused;
69 //---------------------------------------------------------------------------
71 static int loop_edge_cmp(const void* p1, const void* p2, size_t s) {
72 loop_edge_t *e1 = (loop_edge_t*) p1;
73 loop_edge_t *e2 = (loop_edge_t*) p2;
75 return e1->block != e2->block || e1->pos != e2->pos;
78 static int loop_attr_cmp(const void *e1, const void *e2, size_t s) {
79 loop_attr_t *la1 = (loop_attr_t*) e1;
80 loop_attr_t *la2 = (loop_attr_t*) e2;
82 return la1->loop != la2->loop;
85 static int block_attr_cmp(const void *e1, const void *e2, size_t s) {
86 block_attr_t *b1 = (block_attr_t*) e1;
87 block_attr_t *b2 = (block_attr_t*) e2;
89 return b1->block != b2->block;
92 static INLINE int loop_attr_hash(const loop_attr_t *a) {
94 return a->loop->loop_nr;
96 return HASH_PTR(a->loop);
100 static INLINE int block_attr_hash(const block_attr_t *b) {
101 return nodeset_hash(b->block);
104 static INLINE int loop_edge_hash(const loop_edge_t *e) {
105 return nodeset_hash(e->block) ^ (e->pos * 31);
108 static INLINE loop_attr_t *get_loop_attr(morgan_env_t *env, const ir_loop *loop) {
109 loop_attr_t l_attr, *res;
113 hash = loop_attr_hash(&l_attr);
114 res = set_find(env->loop_attr_set, &l_attr, sizeof(l_attr), hash);
116 // create new loop_attr if none exists yet
118 l_attr.out_edges = new_set(loop_edge_cmp, 1);
119 l_attr.in_edges = new_set(loop_edge_cmp, 1);
120 l_attr.livethrough_unused = bitset_obstack_alloc(&env->obst, get_irg_last_idx(env->irg));
121 res = set_insert(env->loop_attr_set, &l_attr, sizeof(l_attr), hash);
127 static INLINE block_attr_t *get_block_attr(morgan_env_t *env, const ir_node *block) {
128 block_attr_t b_attr, *res;
130 b_attr.block = block;
132 hash = block_attr_hash(&b_attr);
133 res = set_find(env->block_attr_set, &b_attr, sizeof(b_attr), hash);
136 b_attr.livethrough_unused = bitset_obstack_alloc(&env->obst, get_irg_last_idx(env->irg));
137 res = set_insert(env->block_attr_set, &b_attr, sizeof(b_attr), hash);
143 //---------------------------------------------------------------------------
145 static INLINE int consider_for_spilling(const arch_env_t *env, const arch_register_class_t *cls, const ir_node *node) {
146 if(!arch_irn_has_reg_class(env, node, -1, cls))
149 return !(arch_irn_get_flags(env, node) & (arch_irn_flags_ignore | arch_irn_flags_dont_spill));
153 * Determine edges going out of a loop (= edges that go to a block that is not inside
154 * the loop or one of its subloops)
156 static INLINE void construct_loop_edges(ir_node* block, void* e) {
157 morgan_env_t *env = (morgan_env_t*) e;
158 int n_cfgpreds = get_Block_n_cfgpreds(block);
160 ir_loop* loop = get_irn_loop(block);
161 loop_attr_t *loop_attr = get_loop_attr(env, loop);
162 DBG((dbg, DBG_LOOPANA, "Loop for %+F: %d (depth %d)\n", block, loop->loop_nr, loop->depth));
164 for(i = 0; i < n_cfgpreds; ++i) {
165 ir_node* cfgpred = get_Block_cfgpred(block, i);
166 ir_node* cfgpred_block = get_nodes_block(cfgpred);
167 ir_loop* cfgpred_loop = get_irn_loop(cfgpred_block);
168 loop_attr_t *outedges = get_loop_attr(env, cfgpred_loop);
170 if(cfgpred_loop == loop)
173 // is it an edge into the loop?
174 if(get_loop_depth(loop) > get_loop_depth(cfgpred_loop)) {
178 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)));
179 set_insert(loop_attr->in_edges, &edge, sizeof(edge), loop_edge_hash(&edge));
181 ir_loop *p_loop = cfgpred_loop;
182 while(get_loop_depth(p_loop) > get_loop_depth(loop)) {
183 p_loop = get_loop_outer_loop(p_loop);
189 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)));
190 set_insert(loop_attr->in_edges, &edge, sizeof(edge), loop_edge_hash(&edge));
194 // an edge out of the loop?
195 if(get_loop_depth(cfgpred_loop) >= get_loop_depth(loop)) {
199 DBG((dbg, DBG_LOOPANA, "Loop out edge from %+F (loop %d) to %+F\n", cfgpred_block, cfgpred_loop->loop_nr, block));
200 set_insert(outedges->out_edges, &edge, sizeof(edge), loop_edge_hash(&edge));
202 ir_loop *o_loop = loop;
204 // we might jump in the middle of another inner loop which is not inside
205 // our loop (happens for irreducible graphs). This would be a
206 // real out edge then.
207 while(get_loop_depth(o_loop) > get_loop_depth(cfgpred_loop)) {
208 o_loop = get_loop_outer_loop(o_loop);
211 if(cfgpred_loop != o_loop) {
215 DBG((dbg, DBG_LOOPANA, "Loop out edge from %+F (loop %d) to %+F (into jump)\n", cfgpred_block, cfgpred_loop->loop_nr, block));
216 set_insert(outedges->out_edges, &edge, sizeof(edge), loop_edge_hash(&edge));
222 static void free_loop_edges(morgan_env_t *env) {
225 for(l_attr = set_first(env->loop_attr_set); l_attr != NULL; l_attr = set_next(env->loop_attr_set)) {
226 del_set(l_attr->out_edges);
227 del_set(l_attr->in_edges);
232 * Debugging help, shows all nodes in a (node-)bitset
234 static void show_nodebitset(ir_graph* irg, const bitset_t* bitset) {
237 bitset_foreach(bitset, i) {
238 ir_node* node = get_idx_irn(irg, i);
239 DBG((dbg, DBG_LIVE, "\t%+F\n", node));
244 * Construct the livethrough unused set for a block
246 static bitset_t *construct_block_livethrough_unused(morgan_env_t* env, const ir_node* block) {
247 block_attr_t *block_attr = get_block_attr(env, block);
251 DBG((dbg, DBG_LIVE, "Processing block %d\n", get_irn_node_nr(block)));
252 // copy all live-outs into the livethrough_unused set
253 be_lv_foreach(env->cenv->lv, block, be_lv_state_in | be_lv_state_out, i) {
254 ir_node *irn = be_lv_get_irn(env->cenv->lv, block, i);
257 if(!consider_for_spilling(env->arch, env->cls, irn))
260 node_idx = get_irn_idx(irn);
261 bitset_set(block_attr->livethrough_unused, node_idx);
265 * All values that are used within the block are not unused (and therefore not
266 * livethrough_unused)
268 sched_foreach(block, node) {
271 for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
272 int idx = get_irn_idx(get_irn_n(node, i));
273 bitset_clear(block_attr->livethrough_unused, idx);
277 show_nodebitset(env->irg, block_attr->livethrough_unused);
278 return block_attr->livethrough_unused;
282 * Construct the livethrough unused set for a loop (and all its subloops+blocks)
284 static bitset_t *construct_loop_livethrough_unused(morgan_env_t *env, const ir_loop *loop) {
286 loop_attr_t* loop_attr = get_loop_attr(env, loop);
288 DBG((dbg, DBG_LIVE, "Processing Loop %d\n", loop->loop_nr));
289 assert(get_loop_n_elements(loop) > 0);
290 for(i = 0; i < get_loop_n_elements(loop); ++i) {
291 loop_element elem = get_loop_element(loop, i);
292 switch (*elem.kind) {
294 bitset_t *livethrough_block_unused;
295 assert(is_Block(elem.node));
296 livethrough_block_unused = construct_block_livethrough_unused(env, elem.node);
298 bitset_copy(loop_attr->livethrough_unused, livethrough_block_unused);
300 bitset_and(loop_attr->livethrough_unused, livethrough_block_unused);
305 bitset_t *livethrough_son_unused;
307 livethrough_son_unused = construct_loop_livethrough_unused(env, elem.son);
309 bitset_copy(loop_attr->livethrough_unused, livethrough_son_unused);
311 bitset_and(loop_attr->livethrough_unused, livethrough_son_unused);
320 DBG((dbg, DBG_LIVE, "Done with loop %d\n", loop->loop_nr));
322 // remove all unused livethroughs that are remembered for this loop from child loops and blocks
323 for(i = 0; i < get_loop_n_elements(loop); ++i) {
324 const loop_element elem = get_loop_element(loop, i);
326 if(*elem.kind == k_ir_loop) {
327 loop_attr_t *son_attr = get_loop_attr(env, elem.son);
328 bitset_andnot(son_attr->livethrough_unused, loop_attr->livethrough_unused);
330 DBG((dbg, DBG_LIVE, "Livethroughs for loop %d:\n", loop->loop_nr));
331 show_nodebitset(env->irg, son_attr->livethrough_unused);
332 } else if(*elem.kind == k_ir_node) {
333 block_attr_t *block_attr = get_block_attr(env, elem.node);
334 bitset_andnot(block_attr->livethrough_unused, loop_attr->livethrough_unused);
336 DBG((dbg, DBG_LIVE, "Livethroughs for block %+F\n", elem.node));
337 show_nodebitset(env->irg, block_attr->livethrough_unused);
343 return loop_attr->livethrough_unused;
346 /*---------------------------------------------------------------------------*/
348 static int reduce_register_pressure_in_block(morgan_env_t *env, const ir_node* block, int loop_unused_spills_possible) {
351 int loop_unused_spills_needed;
352 pset *live_nodes = pset_new_ptr_default();
354 be_liveness_end_of_block(env->cenv->lv, env->arch, env->cls, block, live_nodes);
355 max_pressure = pset_count(live_nodes);
357 DBG((dbg, DBG_LIVE, "Reduce pressure to %d In Block %+F:\n", env->registers_available, block));
360 * Determine register pressure in block
362 sched_foreach_reverse(block, node) {
368 be_liveness_transfer(env->arch, env->cls, node, live_nodes);
369 pressure = pset_count(live_nodes);
370 if(pressure > max_pressure)
371 max_pressure = pressure;
373 del_pset(live_nodes);
375 DBG((dbg, DBG_PRESSURE, "\tMax Pressure in %+F: %d\n", block, max_pressure));
377 loop_unused_spills_needed = max_pressure - env->registers_available;
379 if(loop_unused_spills_needed < 0) {
380 loop_unused_spills_needed = 0;
381 } else if(loop_unused_spills_needed > loop_unused_spills_possible) {
382 loop_unused_spills_needed = loop_unused_spills_possible;
385 DBG((dbg, DBG_PRESSURE, "Unused spills for Block %+F needed: %d\n", block, loop_unused_spills_needed));
386 return loop_unused_spills_needed;
390 * Reduce register pressure in a loop
392 * @param unused_spills_possible Number of spills from livethrough_unused variables possible in outer loops
393 * @return Number of spills of livethrough_unused variables needed in outer loops
395 static int reduce_register_pressure_in_loop(morgan_env_t *env, const ir_loop *loop, int outer_spills_possible) {
397 loop_attr_t* loop_attr = get_loop_attr(env, loop);
398 int spills_needed = 0;
399 int spills_possible = outer_spills_possible + bitset_popcnt(loop_attr->livethrough_unused);
400 int outer_spills_needed;
402 DBG((dbg, DBG_PRESSURE, "Reducing Pressure in loop %d\n", loop->loop_nr));
403 for(i = 0; i < get_loop_n_elements(loop); ++i) {
404 loop_element elem = get_loop_element(loop, i);
405 switch (*elem.kind) {
408 assert(is_Block(elem.node));
409 needed = reduce_register_pressure_in_block(env, elem.node, spills_possible);
411 assert(needed <= spills_possible);
412 if(needed > spills_needed)
413 spills_needed = needed;
417 int needed = reduce_register_pressure_in_loop(env, elem.son, spills_possible);
419 assert(needed <= spills_possible);
420 if(needed > spills_needed)
421 spills_needed = needed;
430 /* calculate number of spills needed in outer loop and spill
431 * unused livethrough nodes around this loop
433 if(spills_needed > outer_spills_possible) {
435 outer_spills_needed = outer_spills_possible;
436 spills_needed -= outer_spills_possible;
438 spills_to_place = spills_needed;
440 bitset_foreach(loop_attr->livethrough_unused, i) {
442 ir_node *to_spill = get_idx_irn(env->irg, i);
444 for(edge = set_first(loop_attr->out_edges); edge != NULL; edge = set_next(loop_attr->out_edges)) {
445 DBG((dbg, DBG_PRESSURE, "Spilling node %+F around loop %d\n", to_spill, loop->loop_nr));
446 be_add_reload_on_edge(env->senv, to_spill, edge->block, edge->pos);
450 if(spills_to_place <= 0) {
455 outer_spills_needed = spills_needed;
458 return outer_spills_needed;
461 void be_spill_morgan(be_chordal_env_t *chordal_env) {
464 FIRM_DBG_REGISTER(dbg, "ir.be.spillmorgan");
465 //firm_dbg_set_mask(dbg, DBG_LOOPANA | DBG_PRESSURE);
467 env.cenv = chordal_env;
468 env.arch = chordal_env->birg->main_env->arch_env;
469 env.irg = chordal_env->irg;
470 env.cls = chordal_env->cls;
471 env.senv = be_new_spill_env(chordal_env);
472 DEBUG_ONLY(be_set_spill_env_dbg_module(env.senv, dbg);)
474 obstack_init(&env.obst);
476 env.registers_available = env.cls->n_regs - be_put_ignore_regs(chordal_env->birg, env.cls, NULL);
478 env.loop_attr_set = new_set(loop_attr_cmp, 5);
479 env.block_attr_set = new_set(block_attr_cmp, 20);
481 /*-- Part1: Analysis --*/
482 be_liveness_recompute(chordal_env->lv);
484 /* construct control flow loop tree */
485 construct_cf_backedges(chordal_env->irg);
487 /* construct loop out edges and livethrough_unused sets for loops and blocks */
488 irg_block_walk_graph(chordal_env->irg, NULL, construct_loop_edges, &env);
489 construct_loop_livethrough_unused(&env, get_irg_loop(env.irg));
491 /*-- Part2: Transformation --*/
493 /* spill unused livethrough values around loops and blocks where
494 * the pressure is too high
496 reduce_register_pressure_in_loop(&env, get_irg_loop(env.irg), 0);
498 /* Insert real spill/reload nodes and fix usages */
499 be_insert_spills_reloads(env.senv);
501 /* Verify the result */
502 if (chordal_env->opts->vrfy_option == BE_CH_VRFY_WARN) {
503 be_verify_schedule(env.irg);
504 } else if (chordal_env->opts->vrfy_option == BE_CH_VRFY_ASSERT) {
505 assert(be_verify_schedule(env.irg));
508 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SPILL)
509 be_dump(env.irg, "-spillmorgan", dump_ir_block_graph_sched);
512 free_loop_edges(&env);
513 del_set(env.loop_attr_set);
514 del_set(env.block_attr_set);
516 /* fix the remaining places with too high register pressure with beladies algorithm */
517 be_spill_belady_spill_env(chordal_env, env.senv);
519 be_delete_spill_env(env.senv);
520 obstack_free(&env.obst, NULL);