2 * Author: Christian Wuerdig
4 * Copyright: (c) Universitaet Karlsruhe
5 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
8 * Performs lowering of perm nodes and spill/reload optimization.
23 #include "bechordal_t.h"
24 #include "besched_t.h"
26 #include "benodesets.h"
29 #include "iredges_t.h"
39 #undef KEEP_ALIVE_COPYKEEP_HACK
42 #define is_Perm(arch_env, irn) (arch_irn_class_is(arch_env, irn, perm))
44 /* associates op with it's copy and CopyKeep */
46 ir_node *op; /* an irn which must be different */
47 pset *copies; /* all non-spillable copies of this irn */
48 const arch_register_class_t *cls;
51 /* environment for constraints */
56 DEBUG_ONLY(firm_dbg_module_t *dbg;)
59 /* lowering walker environment */
60 typedef struct _lower_env_t {
61 be_chordal_env_t *chord_env;
63 DEBUG_ONLY(firm_dbg_module_t *dbg_module;)
66 /* holds a perm register pair */
67 typedef struct _reg_pair_t {
68 const arch_register_t *in_reg; /**< a perm IN register */
69 ir_node *in_node; /**< the in node to which the register belongs */
71 const arch_register_t *out_reg; /**< a perm OUT register */
72 ir_node *out_node; /**< the out node to which the register belongs */
74 int checked; /**< indicates whether the pair was check for cycle or not */
77 typedef enum _perm_type_t {
84 /* structure to represent cycles or chains in a perm */
85 typedef struct _perm_cycle_t {
86 const arch_register_t **elems; /**< the registers in the cycle */
87 int n_elems; /**< number of elements in the cycle */
88 perm_type_t type; /**< type (CHAIN or CYCLE) */
91 static void kill_node(ir_node *irn, int kill_block) {
92 int i, arity = get_irn_arity(irn);
93 ir_graph *irg = get_irn_irg(irn);
95 for (i = -1; i < arity; ++i) {
96 set_irn_n(irn, i, new_r_Bad(irg));
100 /* Compare the two operands */
101 static int cmp_op_copy_assoc(const void *a, const void *b) {
102 const op_copy_assoc_t *op1 = a;
103 const op_copy_assoc_t *op2 = b;
105 return op1->op != op2->op;
108 /* Compare the in registers of two register pairs */
109 static int compare_reg_pair(const void *a, const void *b) {
110 const reg_pair_t *pair_a = a;
111 const reg_pair_t *pair_b = b;
113 if (pair_a->in_reg->index > pair_b->in_reg->index)
119 /* returns the number register pairs marked as checked */
120 static int get_n_checked_pairs(reg_pair_t *pairs, int n) {
121 int i, n_checked = 0;
123 for (i = 0; i < n; i++) {
124 if (pairs[i].checked)
132 * Gets the node corresponding to a register from an array of register pairs.
133 * NOTE: The given registers pairs and the register to look for must belong
134 * to the same register class.
136 * @param pairs The array of register pairs
137 * @param n The number of pairs
138 * @param reg The register to look for
139 * @param in_out 0 == look for IN register, 1 == look for OUT register
140 * @return The corresponding node or NULL if not found
142 static ir_node *get_node_for_register(reg_pair_t *pairs, int n, const arch_register_t *reg, int in_out) {
146 for (i = 0; i < n; i++) {
147 /* out register matches */
148 if (pairs[i].out_reg->index == reg->index)
149 return pairs[i].out_node;
153 for (i = 0; i < n; i++) {
154 /* in register matches */
155 if (pairs[i].in_reg->index == reg->index)
156 return pairs[i].in_node;
164 * Gets the index in the register pair array where the in/out register
165 * corresponds to reg_idx.
167 * @param pairs The array of register pairs
168 * @param n The number of pairs
169 * @param reg The register index to look for
170 * @param in_out 0 == look for IN register, 1 == look for OUT register
171 * @return The corresponding index in pairs or -1 if not found
173 static int get_pairidx_for_regidx(reg_pair_t *pairs, int n, int reg_idx, int in_out) {
177 for (i = 0; i < n; i++) {
178 /* out register matches */
179 if (pairs[i].out_reg->index == reg_idx)
184 for (i = 0; i < n; i++) {
185 /* in register matches */
186 if (pairs[i].in_reg->index == reg_idx)
195 * Gets an array of register pairs and tries to identify a cycle or chain starting
198 * @param cycle Variable to hold the cycle
199 * @param pairs Array of register pairs
200 * @param start Index to start
201 * @return The cycle or chain
203 static perm_cycle_t *get_perm_cycle(perm_cycle_t *cycle, reg_pair_t *pairs, int n, int start) {
204 int head = pairs[start].in_reg->index;
205 int cur_idx = pairs[start].out_reg->index;
206 int cur_pair_idx = start;
207 int n_pairs_done = get_n_checked_pairs(pairs, n);
209 perm_type_t cycle_tp = PERM_CYCLE;
211 /* We could be right in the middle of a chain, so we need to find the start */
212 while (head != cur_idx) {
213 /* goto previous register in cycle or chain */
214 cur_pair_idx = get_pairidx_for_regidx(pairs, n, head, 1);
216 if (cur_pair_idx < 0) {
217 cycle_tp = PERM_CHAIN;
221 head = pairs[cur_pair_idx].in_reg->index;
222 start = cur_pair_idx;
226 /* assume worst case: all remaining pairs build a cycle or chain */
227 cycle->elems = xcalloc((n - n_pairs_done) * 2, sizeof(cycle->elems[0]));
228 cycle->n_elems = 2; /* initial number of elements is 2 */
229 cycle->elems[0] = pairs[start].in_reg;
230 cycle->elems[1] = pairs[start].out_reg;
231 cycle->type = cycle_tp;
232 cur_idx = pairs[start].out_reg->index;
235 /* check for cycle or end of a chain */
236 while (cur_idx != head) {
237 /* goto next register in cycle or chain */
238 cur_pair_idx = get_pairidx_for_regidx(pairs, n, cur_idx, 0);
240 if (cur_pair_idx < 0)
243 cur_idx = pairs[cur_pair_idx].out_reg->index;
245 /* it's not the first element: insert it */
246 if (cur_idx != head) {
247 cycle->elems[idx++] = pairs[cur_pair_idx].out_reg;
251 /* we are there where we started -> CYCLE */
252 cycle->type = PERM_CYCLE;
256 /* mark all pairs having one in/out register with cycle in common as checked */
257 for (idx = 0; idx < cycle->n_elems; idx++) {
258 cur_pair_idx = get_pairidx_for_regidx(pairs, n, cycle->elems[idx]->index, 0);
260 if (cur_pair_idx >= 0)
261 pairs[cur_pair_idx].checked = 1;
263 cur_pair_idx = get_pairidx_for_regidx(pairs, n, cycle->elems[idx]->index, 1);
265 if (cur_pair_idx >= 0)
266 pairs[cur_pair_idx].checked = 1;
273 * Lowers a perm node. Resolves cycles and creates a bunch of
274 * copy and swap operations to permute registers.
275 * Note: The caller of this function has to make sure, that irn
278 * @param irn The perm node
279 * @param block The block the perm node belongs to
280 * @param walk_env The environment
282 static void lower_perm_node(ir_node *irn, void *walk_env) {
283 const arch_register_class_t *reg_class;
284 const arch_env_t *arch_env;
285 lower_env_t *env = walk_env;
288 int n, i, pn, do_copy, j, n_ops;
290 const ir_edge_t *edge;
292 ir_node *sched_point, *block, *in[2];
293 ir_node *arg1, *arg2, *res1, *res2;
294 ir_node *cpyxchg = NULL;
295 DEBUG_ONLY(firm_dbg_module_t *mod;)
297 arch_env = env->chord_env->birg->main_env->arch_env;
298 do_copy = env->do_copy;
299 DEBUG_ONLY(mod = env->dbg_module;)
300 block = get_nodes_block(irn);
303 Get the schedule predecessor node to the perm
304 NOTE: This works with auto-magic. If we insert the
305 new copy/exchange nodes after this node, everything
308 sched_point = sched_prev(irn);
309 DBG((mod, LEVEL_1, "sched point is %+F\n", sched_point));
310 assert(sched_point && "Perm is not scheduled or has no predecessor");
312 n = get_irn_arity(irn);
313 assert(n == get_irn_n_edges(irn) && "perm's in and out numbers different");
315 reg_class = arch_get_irn_register(arch_env, get_irn_n(irn, 0))->reg_class;
316 pairs = alloca(n * sizeof(pairs[0]));
318 /* build the list of register pairs (in, out) */
320 foreach_out_edge(irn, edge) {
321 pairs[i].out_node = get_edge_src_irn(edge);
322 pn = get_Proj_proj(pairs[i].out_node);
323 pairs[i].in_node = get_irn_n(irn, pn);
325 pairs[i].in_reg = arch_get_irn_register(arch_env, pairs[i].in_node);
326 pairs[i].out_reg = arch_get_irn_register(arch_env, pairs[i].out_node);
328 pairs[i].checked = 0;
332 /* sort the register pairs by the indices of the in registers */
333 qsort(pairs, n, sizeof(pairs[0]), compare_reg_pair);
335 /* Mark all equal pairs as checked, and exchange the OUT proj with
337 for (i = 0; i < n; i++) {
338 if (pairs[i].in_reg->index == pairs[i].out_reg->index) {
339 DBG((mod, LEVEL_1, "%+F removing equal perm register pair (%+F, %+F, %s)\n",
340 irn, pairs[i].in_node, pairs[i].out_node, pairs[i].out_reg->name));
342 /* We have to check for a special case:
343 The in-node could be a Proj from a Perm. In this case,
344 we need to correct the projnum */
345 if (is_Perm(arch_env, pairs[i].in_node) && is_Proj(pairs[i].in_node)) {
346 set_Proj_proj(pairs[i].out_node, get_Proj_proj(pairs[i].in_node));
349 /* remove the proj from the schedule */
350 sched_remove(pairs[i].out_node);
352 /* reroute the edges from the proj to the argument */
353 edges_reroute(pairs[i].out_node, pairs[i].in_node, env->chord_env->irg);
354 set_irn_n(pairs[i].out_node, 0, new_Bad());
356 pairs[i].checked = 1;
360 /* Set do_copy to 0 if it's on but we have no free register */
365 real_size = n - get_n_checked_pairs(pairs, n);
367 be_do_stat_perm(reg_class->name, reg_class->n_regs, irn, block, n, real_size);
369 /* check for cycles and chains */
370 while (get_n_checked_pairs(pairs, n) < n) {
373 /* go to the first not-checked pair */
374 while (pairs[i].checked) i++;
375 cycle = xcalloc(1, sizeof(*cycle));
376 cycle = get_perm_cycle(cycle, pairs, n, i);
378 DB((mod, LEVEL_1, "%+F: following %s created:\n ", irn, cycle->type == PERM_CHAIN ? "chain" : "cycle"));
379 for (j = 0; j < cycle->n_elems; j++) {
380 DB((mod, LEVEL_1, " %s", cycle->elems[j]->name));
382 DB((mod, LEVEL_1, "\n"));
385 We don't need to do anything if we have a Perm with two
386 elements which represents a cycle, because those nodes
387 already represent exchange nodes
389 if (n == 2 && cycle->type == PERM_CYCLE) {
395 //TODO: - iff PERM_CYCLE && do_copy -> determine free temp reg and insert copy to/from it before/after
396 // the copy cascade (this reduces the cycle into a chain)
398 /* build copy/swap nodes from back to front */
399 for (i = cycle->n_elems - 2; i >= 0; i--) {
400 arg1 = get_node_for_register(pairs, n, cycle->elems[i], 0);
401 arg2 = get_node_for_register(pairs, n, cycle->elems[i + 1], 0);
403 res1 = get_node_for_register(pairs, n, cycle->elems[i], 1);
404 res2 = get_node_for_register(pairs, n, cycle->elems[i + 1], 1);
406 If we have a cycle and don't copy: we need to create exchange nodes
407 NOTE: An exchange node is a perm node with 2 INs and 2 OUTs
408 IN_1 = in node with register i
409 IN_2 = in node with register i + 1
410 OUT_1 = out node with register i + 1
411 OUT_2 = out node with register i
413 if (cycle->type == PERM_CYCLE && !do_copy) {
417 /* At this point we have to handle the following problem: */
419 /* If we have a cycle with more than two elements, then */
420 /* this could correspond to the following Perm node: */
422 /* +----+ +----+ +----+ */
423 /* | r1 | | r2 | | r3 | */
424 /* +-+--+ +-+--+ +--+-+ */
427 /* +-+--------+---------+-+ */
429 /* +-+--------+---------+-+ */
432 /* +-+--+ +-+--+ +--+-+ */
433 /* |Proj| |Proj| |Proj| */
434 /* | r2 | | r3 | | r1 | */
435 /* +----+ +----+ +----+ */
437 /* This node is about to be split up into two 2x Perm's */
438 /* for which we need 4 Proj's and the one additional Proj */
439 /* of the first Perm has to be one IN of the second. So in */
440 /* general we need to create one additional Proj for each */
441 /* "middle" Perm and set this to one in node of the successor */
444 DBG((mod, LEVEL_1, "%+F creating exchange node (%+F, %s) and (%+F, %s) with\n",
445 irn, arg1, cycle->elems[i]->name, arg2, cycle->elems[i + 1]->name));
446 DBG((mod, LEVEL_1, "%+F (%+F, %s) and (%+F, %s)\n",
447 irn, res1, cycle->elems[i]->name, res2, cycle->elems[i + 1]->name));
449 cpyxchg = be_new_Perm(reg_class, env->chord_env->irg, block, 2, in);
453 /* cycle is not done yet */
454 int pidx = get_pairidx_for_regidx(pairs, n, cycle->elems[i]->index, 0);
456 /* create intermediate proj */
457 res1 = new_r_Proj(get_irn_irg(irn), block, cpyxchg, get_irn_mode(res1), 0);
459 /* set as in for next Perm */
460 pairs[pidx].in_node = res1;
468 set_Proj_pred(res2, cpyxchg);
469 set_Proj_proj(res2, 0);
470 set_Proj_pred(res1, cpyxchg);
471 set_Proj_proj(res1, 1);
473 sched_add_after(sched_point, res1);
474 sched_add_after(sched_point, res2);
476 arch_set_irn_register(arch_env, res2, cycle->elems[i + 1]);
477 arch_set_irn_register(arch_env, res1, cycle->elems[i]);
479 /* insert the copy/exchange node in schedule after the magic schedule node (see above) */
480 sched_add_after(sched_point, cpyxchg);
482 DBG((mod, LEVEL_1, "replacing %+F with %+F, placed new node after %+F\n", irn, cpyxchg, sched_point));
484 /* set the new scheduling point */
488 DBG((mod, LEVEL_1, "%+F creating copy node (%+F, %s) -> (%+F, %s)\n",
489 irn, arg1, cycle->elems[i]->name, res2, cycle->elems[i + 1]->name));
491 cpyxchg = be_new_Copy(reg_class, env->chord_env->irg, block, arg1);
492 arch_set_irn_register(arch_env, cpyxchg, cycle->elems[i + 1]);
495 /* remove the proj from the schedule */
498 /* exchange copy node and proj */
499 exchange(res2, cpyxchg);
501 /* insert the copy/exchange node in schedule after the magic schedule node (see above) */
502 sched_add_after(sched_point, cpyxchg);
504 /* set the new scheduling point */
505 sched_point = cpyxchg;
509 be_do_stat_permcycle(reg_class->name, irn, block, cycle->type == PERM_CHAIN, cycle->n_elems, n_ops);
511 free((void *) cycle->elems);
515 /* remove the perm from schedule */
524 static int get_n_out_edges(const ir_node *irn) {
525 const ir_edge_t *edge;
528 foreach_out_edge(irn, edge) {
535 static ir_node *belower_skip_proj(ir_node *irn) {
537 irn = get_Proj_pred(irn);
541 static ir_node *find_copy(constraint_env_t *env, ir_node *irn, ir_node *op) {
542 const arch_env_t *arch_env = env->birg->main_env->arch_env;
543 ir_node *block = get_nodes_block(irn);
546 for (cur_node = sched_prev(irn);
547 ! is_Block(cur_node) && be_is_Copy(cur_node) && get_nodes_block(cur_node) == block;
548 cur_node = sched_prev(cur_node))
550 if (be_get_Copy_op(cur_node) == op && arch_irn_is(arch_env, cur_node, dont_spill))
557 static void gen_assure_different_pattern(ir_node *irn, ir_node *other_different, constraint_env_t *env) {
558 be_irg_t *birg = env->birg;
559 pset *op_set = env->op_set;
560 const arch_env_t *arch_env = birg->main_env->arch_env;
561 ir_node *block = get_nodes_block(irn);
562 const arch_register_class_t *cls = arch_get_irn_reg_class(arch_env, other_different, -1);
563 ir_node *in[2], *keep, *cpy;
564 op_copy_assoc_t key, *entry;
565 DEBUG_ONLY(firm_dbg_module_t *mod = env->dbg;)
567 if (arch_irn_is(arch_env, other_different, ignore) || ! mode_is_datab(get_irn_mode(other_different))) {
568 DBG((mod, LEVEL_1, "ignore constraint for %+F because other_irn is ignore or not a datab node\n", irn));
572 /* Make a not spillable copy of the different node */
573 /* this is needed because the different irn could be */
574 /* in block far far away */
575 /* The copy is optimized later if not needed */
577 /* check if already exists such a copy in the schedule immediatly before */
578 cpy = find_copy(env, belower_skip_proj(irn), other_different);
580 cpy = be_new_Copy(cls, birg->irg, block, other_different);
581 be_node_set_flags(cpy, BE_OUT_POS(0), arch_irn_flags_dont_spill);
582 DBG((mod, LEVEL_1, "created non-spillable %+F for value %+F\n", cpy, other_different));
585 DBG((mod, LEVEL_1, "using already existing %+F for value %+F\n", cpy, other_different));
591 /* Add the Keep resp. CopyKeep and reroute the users */
592 /* of the other_different irn in case of CopyKeep. */
593 if (get_n_out_edges(other_different) == 0) {
594 keep = be_new_Keep(cls, birg->irg, block, 2, in);
597 keep = be_new_CopyKeep_single(cls, birg->irg, block, cpy, irn, get_irn_mode(other_different));
598 be_node_set_reg_class(keep, 1, cls);
601 DBG((mod, LEVEL_1, "created %+F(%+F, %+F)\n\n", keep, irn, cpy));
603 /* insert copy and keep into schedule */
604 assert(sched_is_scheduled(irn) && "need schedule to assure constraints");
605 if (! sched_is_scheduled(cpy))
606 sched_add_before(belower_skip_proj(irn), cpy);
607 sched_add_after(irn, keep);
609 /* insert the other different and it's copies into the set */
610 key.op = other_different;
612 entry = pset_find(op_set, &key, nodeset_hash(other_different));
615 entry = obstack_alloc(&env->obst, sizeof(*entry));
616 entry->copies = pset_new_ptr_default();
617 entry->op = other_different;
622 pset_insert_ptr(entry->copies, cpy);
624 /* insert keep in case of CopyKeep */
625 if (be_is_CopyKeep(keep))
626 pset_insert_ptr(entry->copies, keep);
628 pset_insert(op_set, entry, nodeset_hash(other_different));
632 * Checks if node has a should_be_different constraint in output
633 * and adds a Keep then to assure the constraint.
635 static void assure_different_constraints(ir_node *irn, constraint_env_t *env) {
636 const arch_register_req_t *req;
637 arch_register_req_t req_temp;
639 req = arch_get_register_req(env->birg->main_env->arch_env, &req_temp, irn, -1);
642 if (arch_register_req_is(req, should_be_different)) {
643 gen_assure_different_pattern(irn, req->other_different, env);
645 else if (arch_register_req_is(req, should_be_different_from_all)) {
646 int i, n = get_irn_arity(belower_skip_proj(irn));
647 for (i = 0; i < n; i++) {
648 gen_assure_different_pattern(irn, get_irn_n(belower_skip_proj(irn), i), env);
657 * Calls the functions to assure register constraints.
659 * @param irn The node to be checked for lowering
660 * @param walk_env The walker environment
662 static void assure_constraints_walker(ir_node *irn, void *walk_env) {
666 if (mode_is_datab(get_irn_mode(irn)))
667 assure_different_constraints(irn, walk_env);
673 * Melt all copykeeps pointing to the same node
674 * (or Projs of the same node), copying the same operand.
676 static void melt_copykeeps(constraint_env_t *cenv) {
677 op_copy_assoc_t *entry;
680 foreach_pset(cenv->op_set, entry) {
684 ir_node **ck_arr, **melt_arr;
688 /* collect all copykeeps */
690 foreach_pset(entry->copies, cp) {
691 if (be_is_CopyKeep(cp)) {
692 obstack_grow(&obst, &cp, sizeof(cp));
695 #ifdef KEEP_ALIVE_COPYKEEP_HACK
697 set_irn_mode(cp, mode_ANY);
700 #endif /* KEEP_ALIVE_COPYKEEP_HACK */
703 /* compare each copykeep with all other copykeeps */
704 ck_arr = (ir_node **)obstack_finish(&obst);
705 for (idx = 0; idx < num_ck; ++idx) {
706 ir_node *ref, *ref_mode_T;
712 ir_node *sched_pt = NULL;
716 ref_mode_T = skip_Proj(get_irn_n(ref, 1));
717 obstack_grow(&obst, &ref, sizeof(ref));
719 DBG((cenv->dbg, LEVEL_1, "Trying to melt %+F:\n", ref));
721 /* check for copykeeps pointing to the same mode_T node as the reference copykeep */
722 for (j = 0; j < num_ck; ++j) {
723 ir_node *cur_ck = ck_arr[j];
725 if (j != idx && cur_ck && skip_Proj(get_irn_n(cur_ck, 1)) == ref_mode_T) {
726 obstack_grow(&obst, &cur_ck, sizeof(cur_ck));
727 pset_remove_ptr(entry->copies, cur_ck);
728 DBG((cenv->dbg, LEVEL_1, "\t%+F\n", cur_ck));
731 sched_remove(cur_ck);
736 /* check, if we found some candidates for melting */
738 DBG((cenv->dbg, LEVEL_1, "\tno candidate found\n"));
742 pset_remove_ptr(entry->copies, ref);
745 melt_arr = (ir_node **)obstack_finish(&obst);
746 /* melt all found copykeeps */
747 NEW_ARR_A(ir_node *, new_ck_in, n_melt);
748 for (j = 0; j < n_melt; ++j) {
749 new_ck_in[j] = get_irn_n(melt_arr[j], 1);
751 /* now, we can kill the melted keep, except the */
752 /* ref one, we still need some information */
753 if (melt_arr[j] != ref)
754 kill_node(melt_arr[j], 0);
757 #ifdef KEEP_ALIVE_COPYKEEP_HACK
758 new_ck = be_new_CopyKeep(entry->cls, cenv->birg->irg, get_nodes_block(ref), be_get_CopyKeep_op(ref), n_melt, new_ck_in, mode_ANY);
761 new_ck = be_new_CopyKeep(entry->cls, cenv->birg->irg, get_nodes_block(ref), be_get_CopyKeep_op(ref), n_melt, new_ck_in, get_irn_mode(ref));
762 #endif /* KEEP_ALIVE_COPYKEEP_HACK */
764 /* set register class for all keeped inputs */
765 for (j = 1; j <= n_melt; ++j)
766 be_node_set_reg_class(new_ck, j, entry->cls);
768 pset_insert_ptr(entry->copies, new_ck);
770 /* find scheduling point */
771 if (get_irn_mode(ref_mode_T) == mode_T) {
772 /* walk along the Projs */
773 for (sched_pt = sched_next(ref_mode_T); is_Proj(sched_pt) || be_is_Keep(sched_pt) || be_is_CopyKeep(sched_pt); sched_pt = sched_next(sched_pt))
774 /* just walk along the schedule until a non-Proj/Keep/CopyKeep node is found*/ ;
777 sched_pt = ref_mode_T;
780 sched_add_before(sched_pt, new_ck);
781 DBG((cenv->dbg, LEVEL_1, "created %+F, scheduled before %+F\n", new_ck, sched_pt));
783 /* finally: kill the reference copykeep */
788 obstack_free(&obst, NULL);
793 * Walks over all nodes to assure register constraints.
795 * @param birg The birg structure containing the irg
797 void assure_constraints(be_irg_t *birg) {
798 constraint_env_t cenv;
799 op_copy_assoc_t *entry;
800 dom_front_info_t *dom;
802 FIRM_DBG_REGISTER(firm_dbg_module_t *mod, "firm.be.lower.constr");
804 DEBUG_ONLY(cenv.dbg = mod;)
806 cenv.op_set = new_pset(cmp_op_copy_assoc, 16);
807 obstack_init(&cenv.obst);
809 irg_walk_blkwise_graph(birg->irg, NULL, assure_constraints_walker, &cenv);
811 /* melt copykeeps, pointing to projs of */
812 /* the same mode_T node and keeping the */
814 melt_copykeeps(&cenv);
816 /* introduce copies needs dominance information */
817 dom = be_compute_dominance_frontiers(birg->irg);
820 foreach_pset(cenv.op_set, entry) {
824 n = pset_count(entry->copies);
825 nodes = alloca((n + 1) * sizeof(nodes[0]));
827 /* put the node in an array */
829 nodes[n++] = entry->op;
830 DBG((mod, LEVEL_1, "introduce copies for %+F ", entry->op));
832 /* collect all copies */
833 foreach_pset(entry->copies, cp) {
835 DB((mod, LEVEL_1, ", %+F ", cp));
838 DB((mod, LEVEL_1, "\n"));
840 /* introduce the copies for the operand and it's copies */
841 be_ssa_constr(dom, NULL, n, nodes);
844 /* Could be that not all CopyKeeps are really needed, */
845 /* so we transform unnecessary ones into Keeps. */
846 foreach_pset(entry->copies, cp) {
847 if (be_is_CopyKeep(cp) && get_irn_n_edges(cp) < 1) {
849 int n = get_irn_arity(cp);
851 keep = be_new_Keep(arch_get_irn_reg_class(birg->main_env->arch_env, cp, -1),
852 birg->irg, get_nodes_block(cp), n, (ir_node **)&get_irn_in(cp)[1]);
853 sched_add_before(cp, keep);
855 /* Set all ins (including the block) of the CopyKeep BAD to keep the verifier happy. */
861 del_pset(entry->copies);
864 be_free_dominance_frontiers(dom);
866 del_pset(cenv.op_set);
867 obstack_free(&cenv.obst, NULL);
873 * Calls the corresponding lowering function for the node.
875 * @param irn The node to be checked for lowering
876 * @param walk_env The walker environment
878 static void lower_nodes_after_ra_walker(ir_node *irn, void *walk_env) {
879 lower_env_t *env = walk_env;
880 const arch_env_t *arch_env = env->chord_env->birg->main_env->arch_env;
882 if (! is_Block(irn) && ! is_Proj(irn)) {
883 if (is_Perm(arch_env, irn)) {
884 lower_perm_node(irn, walk_env);
892 * Walks over all blocks in an irg and performs lowering need to be
893 * done after register allocation (e.g. perm lowering).
895 * @param chord_env The chordal environment containing the irg
896 * @param do_copy 1 == resolve cycles with a free reg if available
898 void lower_nodes_after_ra(be_chordal_env_t *chord_env, int do_copy) {
901 env.chord_env = chord_env;
902 env.do_copy = do_copy;
903 FIRM_DBG_REGISTER(env.dbg_module, "firm.be.lower");
905 irg_walk_blkwise_graph(chord_env->irg, NULL, lower_nodes_after_ra_walker, &env);