2 * Copyright (C) 1995-2007 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * @brief Performs lowering of perm nodes. Inserts copies to assure register constraints.
23 * @author Christian Wuerdig
37 #include "irnodeset.h"
39 #include "iredges_t.h"
45 #include "besched_t.h"
47 #include "bessaconstr.h"
48 #include "benodesets.h"
50 #undef KEEP_ALIVE_COPYKEEP_HACK
52 /* associates op with it's copy and CopyKeep */
54 ir_node *op; /* an irn which must be different */
55 ir_nodeset_t copies; /* all non-spillable copies of this irn */
56 const arch_register_class_t *cls;
59 /* environment for constraints */
64 DEBUG_ONLY(firm_dbg_module_t *dbg;)
67 /* lowering walker environment */
68 typedef struct _lower_env_t {
70 const arch_env_t *arch_env;
72 DEBUG_ONLY(firm_dbg_module_t *dbg_module;)
75 /* holds a perm register pair */
76 typedef struct _reg_pair_t {
77 const arch_register_t *in_reg; /**< a perm IN register */
78 ir_node *in_node; /**< the in node to which the register belongs */
80 const arch_register_t *out_reg; /**< a perm OUT register */
81 ir_node *out_node; /**< the out node to which the register belongs */
83 int checked; /**< indicates whether the pair was check for cycle or not */
86 typedef enum _perm_type_t {
93 /* structure to represent cycles or chains in a perm */
94 typedef struct _perm_cycle_t {
95 const arch_register_t **elems; /**< the registers in the cycle */
96 int n_elems; /**< number of elements in the cycle */
97 perm_type_t type; /**< type (CHAIN or CYCLE) */
101 /* Compare the two operands */
102 static int cmp_op_copy_assoc(const void *a, const void *b) {
103 const op_copy_assoc_t *op1 = a;
104 const op_copy_assoc_t *op2 = b;
106 return op1->op != op2->op;
109 /* Compare the in registers of two register pairs */
110 static int compare_reg_pair(const void *a, const void *b) {
111 const reg_pair_t *pair_a = a;
112 const reg_pair_t *pair_b = b;
114 if (pair_a->in_reg->index > pair_b->in_reg->index)
120 /* returns the number register pairs marked as checked */
121 static int get_n_checked_pairs(reg_pair_t *pairs, int n) {
122 int i, n_checked = 0;
124 for (i = 0; i < n; i++) {
125 if (pairs[i].checked)
133 * Gets the node corresponding to a register from an array of register pairs.
134 * NOTE: The given registers pairs and the register to look for must belong
135 * to the same register class.
137 * @param pairs The array of register pairs
138 * @param n The number of pairs
139 * @param reg The register to look for
140 * @param in_out 0 == look for IN register, 1 == look for OUT register
141 * @return The corresponding node or NULL if not found
143 static ir_node *get_node_for_register(reg_pair_t *pairs, int n, const arch_register_t *reg, int in_out) {
147 for (i = 0; i < n; i++) {
148 /* out register matches */
149 if (pairs[i].out_reg->index == reg->index)
150 return pairs[i].out_node;
154 for (i = 0; i < n; i++) {
155 /* in register matches */
156 if (pairs[i].in_reg->index == reg->index)
157 return pairs[i].in_node;
165 * Gets the index in the register pair array where the in/out register
166 * corresponds to reg_idx.
168 * @param pairs The array of register pairs
169 * @param n The number of pairs
170 * @param reg The register index to look for
171 * @param in_out 0 == look for IN register, 1 == look for OUT register
172 * @return The corresponding index in pairs or -1 if not found
174 static int get_pairidx_for_regidx(reg_pair_t *pairs, int n, int reg_idx, int in_out) {
178 for (i = 0; i < n; i++) {
179 /* out register matches */
180 if (pairs[i].out_reg->index == reg_idx)
185 for (i = 0; i < n; i++) {
186 /* in register matches */
187 if (pairs[i].in_reg->index == reg_idx)
196 * Gets an array of register pairs and tries to identify a cycle or chain starting
199 * @param cycle Variable to hold the cycle
200 * @param pairs Array of register pairs
201 * @param start Index to start
202 * @return The cycle or chain
204 static perm_cycle_t *get_perm_cycle(perm_cycle_t *cycle, reg_pair_t *pairs, int n, int start) {
205 int head = pairs[start].in_reg->index;
206 int cur_idx = pairs[start].out_reg->index;
207 int cur_pair_idx = start;
208 int n_pairs_done = get_n_checked_pairs(pairs, n);
210 perm_type_t cycle_tp = PERM_CYCLE;
212 /* We could be right in the middle of a chain, so we need to find the start */
213 while (head != cur_idx) {
214 /* goto previous register in cycle or chain */
215 cur_pair_idx = get_pairidx_for_regidx(pairs, n, head, 1);
217 if (cur_pair_idx < 0) {
218 cycle_tp = PERM_CHAIN;
222 head = pairs[cur_pair_idx].in_reg->index;
223 start = cur_pair_idx;
227 /* assume worst case: all remaining pairs build a cycle or chain */
228 cycle->elems = xcalloc((n - n_pairs_done) * 2, sizeof(cycle->elems[0]));
229 cycle->n_elems = 2; /* initial number of elements is 2 */
230 cycle->elems[0] = pairs[start].in_reg;
231 cycle->elems[1] = pairs[start].out_reg;
232 cycle->type = cycle_tp;
233 cur_idx = pairs[start].out_reg->index;
236 /* check for cycle or end of a chain */
237 while (cur_idx != head) {
238 /* goto next register in cycle or chain */
239 cur_pair_idx = get_pairidx_for_regidx(pairs, n, cur_idx, 0);
241 if (cur_pair_idx < 0)
244 cur_idx = pairs[cur_pair_idx].out_reg->index;
246 /* it's not the first element: insert it */
247 if (cur_idx != head) {
248 cycle->elems[idx++] = pairs[cur_pair_idx].out_reg;
252 /* we are there where we started -> CYCLE */
253 cycle->type = PERM_CYCLE;
257 /* mark all pairs having one in/out register with cycle in common as checked */
258 for (idx = 0; idx < cycle->n_elems; idx++) {
259 cur_pair_idx = get_pairidx_for_regidx(pairs, n, cycle->elems[idx]->index, 0);
261 if (cur_pair_idx >= 0)
262 pairs[cur_pair_idx].checked = 1;
264 cur_pair_idx = get_pairidx_for_regidx(pairs, n, cycle->elems[idx]->index, 1);
266 if (cur_pair_idx >= 0)
267 pairs[cur_pair_idx].checked = 1;
274 * Lowers a perm node. Resolves cycles and creates a bunch of
275 * copy and swap operations to permute registers.
276 * Note: The caller of this function has to make sure, that irn
279 * @param irn The perm node
280 * @param block The block the perm node belongs to
281 * @param walk_env The environment
283 static void lower_perm_node(ir_node *irn, void *walk_env) {
284 ir_graph *irg = get_irn_irg(irn);
285 const arch_register_class_t *reg_class;
286 const arch_env_t *arch_env;
287 lower_env_t *env = walk_env;
290 int n, i, pn, do_copy, j, n_ops;
292 const ir_edge_t *edge;
294 ir_node *sched_point, *block, *in[2];
295 ir_node *arg1, *arg2, *res1, *res2;
296 ir_node *cpyxchg = NULL;
297 DEBUG_ONLY(firm_dbg_module_t *mod;)
299 arch_env = env->arch_env;
300 do_copy = env->do_copy;
301 DEBUG_ONLY(mod = env->dbg_module;)
302 block = get_nodes_block(irn);
305 Get the schedule predecessor node to the perm
306 NOTE: This works with auto-magic. If we insert the
307 new copy/exchange nodes after this node, everything
310 sched_point = sched_prev(irn);
311 DBG((mod, LEVEL_1, "sched point is %+F\n", sched_point));
312 assert(sched_point && "Perm is not scheduled or has no predecessor");
314 n = get_irn_arity(irn);
315 assert(n == get_irn_n_edges(irn) && "perm's in and out numbers different");
317 reg_class = arch_get_irn_register(arch_env, get_irn_n(irn, 0))->reg_class;
318 pairs = alloca(n * sizeof(pairs[0]));
320 /* build the list of register pairs (in, out) */
322 foreach_out_edge(irn, edge) {
323 pairs[i].out_node = get_edge_src_irn(edge);
324 pn = get_Proj_proj(pairs[i].out_node);
325 pairs[i].in_node = get_irn_n(irn, pn);
327 pairs[i].in_reg = arch_get_irn_register(arch_env, pairs[i].in_node);
328 pairs[i].out_reg = arch_get_irn_register(arch_env, pairs[i].out_node);
330 pairs[i].checked = 0;
334 /* sort the register pairs by the indices of the in registers */
335 qsort(pairs, n, sizeof(pairs[0]), compare_reg_pair);
337 /* Mark all equal pairs as checked, and exchange the OUT proj with
339 for (i = 0; i < n; i++) {
340 if (pairs[i].in_reg->index == pairs[i].out_reg->index) {
341 DBG((mod, LEVEL_1, "%+F removing equal perm register pair (%+F, %+F, %s)\n",
342 irn, pairs[i].in_node, pairs[i].out_node, pairs[i].out_reg->name));
344 /* We have to check for a special case:
345 The in-node could be a Proj from a Perm. In this case,
346 we need to correct the projnum */
347 if (be_is_Perm(pairs[i].in_node) && is_Proj(pairs[i].in_node)) {
348 set_Proj_proj(pairs[i].out_node, get_Proj_proj(pairs[i].in_node));
351 /* remove the proj from the schedule */
352 sched_remove(pairs[i].out_node);
354 /* reroute the edges from the proj to the argument */
355 exchange(pairs[i].out_node, pairs[i].in_node);
356 //edges_reroute(pairs[i].out_node, pairs[i].in_node, env->birg->irg);
357 //set_irn_n(pairs[i].out_node, 0, new_Bad());
359 pairs[i].checked = 1;
363 /* Set do_copy to 0 if it's on but we have no free register */
368 real_size = n - get_n_checked_pairs(pairs, n);
370 be_do_stat_perm(reg_class->name, reg_class->n_regs, irn, block, n, real_size);
372 /* check for cycles and chains */
373 while (get_n_checked_pairs(pairs, n) < n) {
376 /* go to the first not-checked pair */
377 while (pairs[i].checked) i++;
378 cycle = xcalloc(1, sizeof(*cycle));
379 cycle = get_perm_cycle(cycle, pairs, n, i);
381 DB((mod, LEVEL_1, "%+F: following %s created:\n ", irn, cycle->type == PERM_CHAIN ? "chain" : "cycle"));
382 for (j = 0; j < cycle->n_elems; j++) {
383 DB((mod, LEVEL_1, " %s", cycle->elems[j]->name));
385 DB((mod, LEVEL_1, "\n"));
388 We don't need to do anything if we have a Perm with two
389 elements which represents a cycle, because those nodes
390 already represent exchange nodes
392 if (n == 2 && cycle->type == PERM_CYCLE) {
398 //TODO: - iff PERM_CYCLE && do_copy -> determine free temp reg and insert copy to/from it before/after
399 // the copy cascade (this reduces the cycle into a chain)
401 /* build copy/swap nodes from back to front */
402 for (i = cycle->n_elems - 2; i >= 0; i--) {
403 arg1 = get_node_for_register(pairs, n, cycle->elems[i], 0);
404 arg2 = get_node_for_register(pairs, n, cycle->elems[i + 1], 0);
406 res1 = get_node_for_register(pairs, n, cycle->elems[i], 1);
407 res2 = get_node_for_register(pairs, n, cycle->elems[i + 1], 1);
409 If we have a cycle and don't copy: we need to create exchange nodes
410 NOTE: An exchange node is a perm node with 2 INs and 2 OUTs
411 IN_1 = in node with register i
412 IN_2 = in node with register i + 1
413 OUT_1 = out node with register i + 1
414 OUT_2 = out node with register i
416 if (cycle->type == PERM_CYCLE && !do_copy) {
420 /* At this point we have to handle the following problem: */
422 /* If we have a cycle with more than two elements, then */
423 /* this could correspond to the following Perm node: */
425 /* +----+ +----+ +----+ */
426 /* | r1 | | r2 | | r3 | */
427 /* +-+--+ +-+--+ +--+-+ */
430 /* +-+--------+---------+-+ */
432 /* +-+--------+---------+-+ */
435 /* +-+--+ +-+--+ +--+-+ */
436 /* |Proj| |Proj| |Proj| */
437 /* | r2 | | r3 | | r1 | */
438 /* +----+ +----+ +----+ */
440 /* This node is about to be split up into two 2x Perm's */
441 /* for which we need 4 Proj's and the one additional Proj */
442 /* of the first Perm has to be one IN of the second. So in */
443 /* general we need to create one additional Proj for each */
444 /* "middle" Perm and set this to one in node of the successor */
447 DBG((mod, LEVEL_1, "%+F creating exchange node (%+F, %s) and (%+F, %s) with\n",
448 irn, arg1, cycle->elems[i]->name, arg2, cycle->elems[i + 1]->name));
449 DBG((mod, LEVEL_1, "%+F (%+F, %s) and (%+F, %s)\n",
450 irn, res1, cycle->elems[i]->name, res2, cycle->elems[i + 1]->name));
452 cpyxchg = be_new_Perm(reg_class, irg, block, 2, in);
456 /* cycle is not done yet */
457 int pidx = get_pairidx_for_regidx(pairs, n, cycle->elems[i]->index, 0);
459 /* create intermediate proj */
460 res1 = new_r_Proj(irg, block, cpyxchg, get_irn_mode(res1), 0);
462 /* set as in for next Perm */
463 pairs[pidx].in_node = res1;
471 set_Proj_pred(res2, cpyxchg);
472 set_Proj_proj(res2, 0);
473 set_Proj_pred(res1, cpyxchg);
474 set_Proj_proj(res1, 1);
476 sched_add_after(sched_point, res1);
477 sched_add_after(sched_point, res2);
479 arch_set_irn_register(arch_env, res2, cycle->elems[i + 1]);
480 arch_set_irn_register(arch_env, res1, cycle->elems[i]);
482 /* insert the copy/exchange node in schedule after the magic schedule node (see above) */
483 sched_add_after(sched_point, cpyxchg);
485 DBG((mod, LEVEL_1, "replacing %+F with %+F, placed new node after %+F\n", irn, cpyxchg, sched_point));
487 /* set the new scheduling point */
491 DBG((mod, LEVEL_1, "%+F creating copy node (%+F, %s) -> (%+F, %s)\n",
492 irn, arg1, cycle->elems[i]->name, res2, cycle->elems[i + 1]->name));
494 cpyxchg = be_new_Copy(reg_class, irg, block, arg1);
495 arch_set_irn_register(arch_env, cpyxchg, cycle->elems[i + 1]);
498 /* remove the proj from the schedule */
501 /* exchange copy node and proj */
502 exchange(res2, cpyxchg);
504 /* insert the copy/exchange node in schedule after the magic schedule node (see above) */
505 sched_add_after(sched_point, cpyxchg);
507 /* set the new scheduling point */
508 sched_point = cpyxchg;
512 be_do_stat_permcycle(reg_class->name, irn, block, cycle->type == PERM_CHAIN, cycle->n_elems, n_ops);
514 free((void *) cycle->elems);
518 /* remove the perm from schedule */
527 static int get_n_out_edges(const ir_node *irn) {
528 const ir_edge_t *edge;
531 foreach_out_edge(irn, edge) {
538 static INLINE ir_node *belower_skip_proj(ir_node *irn) {
540 irn = get_Proj_pred(irn);
544 static ir_node *find_copy(constraint_env_t *env, ir_node *irn, ir_node *op) {
545 const arch_env_t *arch_env = be_get_birg_arch_env(env->birg);
546 ir_node *block = get_nodes_block(irn);
549 for (cur_node = sched_prev(irn);
550 ! is_Block(cur_node) && be_is_Copy(cur_node) && get_nodes_block(cur_node) == block;
551 cur_node = sched_prev(cur_node))
553 if (be_get_Copy_op(cur_node) == op && arch_irn_is(arch_env, cur_node, dont_spill))
560 static void gen_assure_different_pattern(ir_node *irn, ir_node *other_different, constraint_env_t *env) {
561 be_irg_t *birg = env->birg;
562 ir_graph *irg = be_get_birg_irg(birg);
563 pset *op_set = env->op_set;
564 const arch_env_t *arch_env = be_get_birg_arch_env(birg);
565 ir_node *block = get_nodes_block(irn);
566 const arch_register_class_t *cls = arch_get_irn_reg_class(arch_env, other_different, -1);
567 ir_node *in[2], *keep, *cpy;
568 op_copy_assoc_t key, *entry;
569 DEBUG_ONLY(firm_dbg_module_t *mod = env->dbg;)
571 if (arch_irn_is(arch_env, other_different, ignore) || ! mode_is_datab(get_irn_mode(other_different))) {
572 DBG((mod, LEVEL_1, "ignore constraint for %+F because other_irn is ignore or not a datab node\n", irn));
576 /* Make a not spillable copy of the different node */
577 /* this is needed because the different irn could be */
578 /* in block far far away */
579 /* The copy is optimized later if not needed */
581 /* check if already exists such a copy in the schedule immediatly before */
582 cpy = find_copy(env, belower_skip_proj(irn), other_different);
584 cpy = be_new_Copy(cls, irg, block, other_different);
585 be_node_set_flags(cpy, BE_OUT_POS(0), arch_irn_flags_dont_spill);
586 DBG((mod, LEVEL_1, "created non-spillable %+F for value %+F\n", cpy, other_different));
589 DBG((mod, LEVEL_1, "using already existing %+F for value %+F\n", cpy, other_different));
595 /* Add the Keep resp. CopyKeep and reroute the users */
596 /* of the other_different irn in case of CopyKeep. */
597 if (get_n_out_edges(other_different) == 0) {
598 keep = be_new_Keep(cls, irg, block, 2, in);
601 keep = be_new_CopyKeep_single(cls, irg, block, cpy, irn, get_irn_mode(other_different));
602 be_node_set_reg_class(keep, 1, cls);
605 DBG((mod, LEVEL_1, "created %+F(%+F, %+F)\n\n", keep, irn, cpy));
607 /* insert copy and keep into schedule */
608 assert(sched_is_scheduled(irn) && "need schedule to assure constraints");
609 if (! sched_is_scheduled(cpy))
610 sched_add_before(belower_skip_proj(irn), cpy);
611 sched_add_after(irn, keep);
613 /* insert the other different and it's copies into the set */
614 key.op = other_different;
615 entry = pset_find(op_set, &key, nodeset_hash(other_different));
618 entry = obstack_alloc(&env->obst, sizeof(*entry));
619 ir_nodeset_init(&entry->copies);
620 entry->op = other_different;
625 ir_nodeset_insert(&entry->copies, cpy);
627 /* insert keep in case of CopyKeep */
628 if (be_is_CopyKeep(keep)) {
629 ir_nodeset_insert(&entry->copies, keep);
632 pset_insert(op_set, entry, nodeset_hash(other_different));
636 * Checks if node has a should_be_different constraint in output
637 * and adds a Keep then to assure the constraint.
639 static void assure_different_constraints(ir_node *irn, constraint_env_t *env) {
640 const arch_register_req_t *req;
641 const arch_env_t *arch_env = be_get_birg_arch_env(env->birg);
643 req = arch_get_register_req(arch_env, irn, -1);
645 if (arch_register_req_is(req, should_be_different)) {
646 ir_node *different_from = get_irn_n(belower_skip_proj(irn), req->other_different);
647 gen_assure_different_pattern(irn, different_from, env);
648 } else if (arch_register_req_is(req, should_be_different_from_all)) {
649 int i, n = get_irn_arity(belower_skip_proj(irn));
650 for (i = 0; i < n; i++) {
651 gen_assure_different_pattern(irn, get_irn_n(belower_skip_proj(irn), i), env);
659 * Calls the functions to assure register constraints.
661 * @param irn The node to be checked for lowering
662 * @param walk_env The walker environment
664 static void assure_constraints_walker(ir_node *irn, void *walk_env) {
668 if (sched_is_scheduled(irn) && mode_is_datab(get_irn_mode(irn)))
669 assure_different_constraints(irn, walk_env);
675 * Melt all copykeeps pointing to the same node
676 * (or Projs of the same node), copying the same operand.
678 static void melt_copykeeps(constraint_env_t *cenv) {
679 be_irg_t *birg = cenv->birg;
680 ir_graph *irg = be_get_birg_irg(birg);
681 op_copy_assoc_t *entry;
684 foreach_pset(cenv->op_set, entry) {
688 ir_nodeset_iterator_t iter;
689 ir_node **ck_arr, **melt_arr;
693 /* collect all copykeeps */
695 foreach_ir_nodeset(&entry->copies, cp, iter) {
696 if (be_is_CopyKeep(cp)) {
697 obstack_grow(&obst, &cp, sizeof(cp));
700 #ifdef KEEP_ALIVE_COPYKEEP_HACK
702 set_irn_mode(cp, mode_ANY);
705 #endif /* KEEP_ALIVE_COPYKEEP_HACK */
708 /* compare each copykeep with all other copykeeps */
709 ck_arr = (ir_node **)obstack_finish(&obst);
710 for (idx = 0; idx < num_ck; ++idx) {
711 ir_node *ref, *ref_mode_T;
717 ir_node *sched_pt = NULL;
721 ref_mode_T = skip_Proj(get_irn_n(ref, 1));
722 obstack_grow(&obst, &ref, sizeof(ref));
724 DBG((cenv->dbg, LEVEL_1, "Trying to melt %+F:\n", ref));
726 /* check for copykeeps pointing to the same mode_T node as the reference copykeep */
727 for (j = 0; j < num_ck; ++j) {
728 ir_node *cur_ck = ck_arr[j];
730 if (j != idx && cur_ck && skip_Proj(get_irn_n(cur_ck, 1)) == ref_mode_T) {
731 obstack_grow(&obst, &cur_ck, sizeof(cur_ck));
732 ir_nodeset_remove(&entry->copies, cur_ck);
733 DBG((cenv->dbg, LEVEL_1, "\t%+F\n", cur_ck));
736 sched_remove(cur_ck);
741 /* check, if we found some candidates for melting */
743 DBG((cenv->dbg, LEVEL_1, "\tno candidate found\n"));
747 ir_nodeset_remove(&entry->copies, ref);
750 melt_arr = (ir_node **)obstack_finish(&obst);
751 /* melt all found copykeeps */
752 NEW_ARR_A(ir_node *, new_ck_in, n_melt);
753 for (j = 0; j < n_melt; ++j) {
754 new_ck_in[j] = get_irn_n(melt_arr[j], 1);
756 /* now, we can kill the melted keep, except the */
757 /* ref one, we still need some information */
758 if (melt_arr[j] != ref)
759 be_kill_node(melt_arr[j]);
762 #ifdef KEEP_ALIVE_COPYKEEP_HACK
763 new_ck = be_new_CopyKeep(entry->cls, irg, get_nodes_block(ref), be_get_CopyKeep_op(ref), n_melt, new_ck_in, mode_ANY);
766 new_ck = be_new_CopyKeep(entry->cls, irg, get_nodes_block(ref), be_get_CopyKeep_op(ref), n_melt, new_ck_in, get_irn_mode(ref));
767 #endif /* KEEP_ALIVE_COPYKEEP_HACK */
769 /* set register class for all keeped inputs */
770 for (j = 1; j <= n_melt; ++j)
771 be_node_set_reg_class(new_ck, j, entry->cls);
773 ir_nodeset_insert(&entry->copies, new_ck);
775 /* find scheduling point */
776 if (get_irn_mode(ref_mode_T) == mode_T) {
777 /* walk along the Projs */
778 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))
779 /* just walk along the schedule until a non-Proj/Keep/CopyKeep node is found*/ ;
782 sched_pt = ref_mode_T;
785 sched_add_before(sched_pt, new_ck);
786 DBG((cenv->dbg, LEVEL_1, "created %+F, scheduled before %+F\n", new_ck, sched_pt));
788 /* finally: kill the reference copykeep */
793 obstack_free(&obst, NULL);
798 * Walks over all nodes to assure register constraints.
800 * @param birg The birg structure containing the irg
802 void assure_constraints(be_irg_t *birg) {
803 ir_graph *irg = be_get_birg_irg(birg);
804 const arch_env_t *arch_env = be_get_birg_arch_env(birg);
805 constraint_env_t cenv;
806 op_copy_assoc_t *entry;
808 FIRM_DBG_REGISTER(firm_dbg_module_t *mod, "firm.be.lower.constr");
810 be_assure_dom_front(birg);
812 DEBUG_ONLY(cenv.dbg = mod;)
814 cenv.op_set = new_pset(cmp_op_copy_assoc, 16);
815 obstack_init(&cenv.obst);
817 irg_walk_blkwise_graph(irg, NULL, assure_constraints_walker, &cenv);
819 /* melt copykeeps, pointing to projs of */
820 /* the same mode_T node and keeping the */
822 melt_copykeeps(&cenv);
825 foreach_pset(cenv.op_set, entry) {
828 ir_nodeset_iterator_t iter;
829 be_ssa_construction_env_t senv;
831 n = ir_nodeset_size(&entry->copies);
832 nodes = alloca(n * sizeof(nodes[0]));
834 /* put the node in an array */
835 DBG((mod, LEVEL_1, "introduce copies for %+F ", entry->op));
837 /* collect all copies */
839 foreach_ir_nodeset(&entry->copies, cp, iter) {
841 DB((mod, LEVEL_1, ", %+F ", cp));
844 DB((mod, LEVEL_1, "\n"));
846 /* introduce the copies for the operand and it's copies */
847 be_ssa_construction_init(&senv, birg);
848 be_ssa_construction_add_copy(&senv, entry->op);
849 be_ssa_construction_add_copies(&senv, nodes, n);
850 be_ssa_construction_fix_users(&senv, entry->op);
851 be_ssa_construction_destroy(&senv);
853 /* Could be that not all CopyKeeps are really needed, */
854 /* so we transform unnecessary ones into Keeps. */
855 foreach_ir_nodeset(&entry->copies, cp, iter) {
856 if (be_is_CopyKeep(cp) && get_irn_n_edges(cp) < 1) {
858 int n = get_irn_arity(cp);
860 keep = be_new_Keep(arch_get_irn_reg_class(arch_env, cp, -1),
861 irg, get_nodes_block(cp), n, (ir_node **)&get_irn_in(cp)[1]);
862 sched_add_before(cp, keep);
864 /* Set all ins (including the block) of the CopyKeep BAD to keep the verifier happy. */
870 ir_nodeset_destroy(&entry->copies);
873 del_pset(cenv.op_set);
874 obstack_free(&cenv.obst, NULL);
875 be_invalidate_liveness(birg);
881 * Calls the corresponding lowering function for the node.
883 * @param irn The node to be checked for lowering
884 * @param walk_env The walker environment
886 static void lower_nodes_after_ra_walker(ir_node *irn, void *walk_env) {
887 if (! is_Block(irn) && ! is_Proj(irn)) {
888 if (be_is_Perm(irn)) {
889 lower_perm_node(irn, walk_env);
897 * Walks over all blocks in an irg and performs lowering need to be
898 * done after register allocation (e.g. perm lowering).
900 * @param birg The birg object
901 * @param do_copy 1 == resolve cycles with a free reg if available
903 void lower_nodes_after_ra(be_irg_t *birg, int do_copy) {
905 ir_graph *irg = be_get_birg_irg(birg);
908 env.arch_env = be_get_birg_arch_env(birg);
909 env.do_copy = do_copy;
910 FIRM_DBG_REGISTER(env.dbg_module, "firm.be.lower");
912 irg_walk_blkwise_graph(irg, NULL, lower_nodes_after_ra_walker, &env);