2 * Copyright (C) 1995-2008 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
35 #include "irnodeset.h"
36 #include "irnodemap.h"
38 #include "iredges_t.h"
45 #include "besched_t.h"
47 #include "bessaconstr.h"
48 #include "beintlive_t.h"
50 #undef KEEP_ALIVE_COPYKEEP_HACK
52 /** Associates an ir_node with it's copy and CopyKeep. */
54 ir_nodeset_t copies; /**< all non-spillable copies of this irn */
55 const arch_register_class_t *cls;
58 /** Environment for constraints. */
63 DEBUG_ONLY(firm_dbg_module_t *dbg;)
66 /** Lowering walker environment. */
67 typedef struct _lower_env_t {
70 DEBUG_ONLY(firm_dbg_module_t *dbg_module;)
73 /** Holds a Perm register pair. */
74 typedef struct _reg_pair_t {
75 const arch_register_t *in_reg; /**< a perm IN register */
76 ir_node *in_node; /**< the in node to which the register belongs */
78 const arch_register_t *out_reg; /**< a perm OUT register */
79 ir_node *out_node; /**< the out node to which the register belongs */
81 int checked; /**< indicates whether the pair was check for cycle or not */
84 typedef enum _perm_type_t {
91 /** Structure to represent cycles or chains in a Perm. */
92 typedef struct _perm_cycle_t {
93 const arch_register_t **elems; /**< the registers in the cycle */
94 int n_elems; /**< number of elements in the cycle */
95 perm_type_t type; /**< type (CHAIN or CYCLE) */
98 /** Compare the in registers of two register pairs. */
99 static int compare_reg_pair(const void *a, const void *b) {
100 const reg_pair_t *pair_a = a;
101 const reg_pair_t *pair_b = b;
103 if (pair_a->in_reg->index > pair_b->in_reg->index)
109 /** returns the number register pairs marked as checked. */
110 static int get_n_checked_pairs(reg_pair_t *pairs, int n) {
111 int i, n_checked = 0;
113 for (i = 0; i < n; i++) {
114 if (pairs[i].checked)
122 * Gets the node corresponding to an IN register from an array of register pairs.
123 * NOTE: The given registers pairs and the register to look for must belong
124 * to the same register class.
126 * @param pairs The array of register pairs
127 * @param n The number of pairs
128 * @param reg The register to look for
129 * @return The corresponding node or NULL if not found
131 static ir_node *get_node_for_in_register(reg_pair_t *pairs, int n, const arch_register_t *reg) {
134 for (i = 0; i < n; i++) {
135 /* in register matches */
136 if (pairs[i].in_reg->index == reg->index)
137 return pairs[i].in_node;
144 * Gets the node corresponding to an OUT register from an array of register pairs.
145 * NOTE: The given registers pairs and the register to look for must belong
146 * to the same register class.
148 * @param pairs The array of register pairs
149 * @param n The number of pairs
150 * @param reg The register to look for
151 * @return The corresponding node or NULL if not found
153 static ir_node *get_node_for_out_register(reg_pair_t *pairs, int n, const arch_register_t *reg) {
156 for (i = 0; i < n; i++) {
157 /* out register matches */
158 if (pairs[i].out_reg->index == reg->index)
159 return pairs[i].out_node;
166 * Gets the index in the register pair array where the in/out register
167 * corresponds to reg_idx.
169 * @param pairs The array of register pairs
170 * @param n The number of pairs
171 * @param reg The register index to look for
172 * @param in_out 0 == look for IN register, 1 == look for OUT register
173 * @return The corresponding index in pairs or -1 if not found
175 static int get_pairidx_for_regidx(reg_pair_t *pairs, int n, int reg_idx, int in_out) {
179 for (i = 0; i < n; i++) {
180 /* out register matches */
181 if ((int) pairs[i].out_reg->index == reg_idx)
186 for (i = 0; i < n; i++) {
187 /* in register matches */
188 if ((int) pairs[i].in_reg->index == reg_idx)
197 * Gets an array of register pairs and tries to identify a cycle or chain starting
200 * @param cycle Variable to hold the cycle
201 * @param pairs Array of register pairs
202 * @param start Index to start
203 * @return The cycle or chain
205 static perm_cycle_t *get_perm_cycle(perm_cycle_t *cycle, reg_pair_t *pairs, int n, int start) {
206 int head = pairs[start].in_reg->index;
207 int cur_idx = pairs[start].out_reg->index;
208 int cur_pair_idx = start;
209 int n_pairs_done = get_n_checked_pairs(pairs, n);
211 perm_type_t cycle_tp = PERM_CYCLE;
213 /* We could be right in the middle of a chain, so we need to find the start */
214 while (head != cur_idx) {
215 /* goto previous register in cycle or chain */
216 cur_pair_idx = get_pairidx_for_regidx(pairs, n, head, 1);
218 if (cur_pair_idx < 0) {
219 cycle_tp = PERM_CHAIN;
223 head = pairs[cur_pair_idx].in_reg->index;
224 start = cur_pair_idx;
228 /* assume worst case: all remaining pairs build a cycle or chain */
229 cycle->elems = XMALLOCNZ(const arch_register_t*, (n - n_pairs_done) * 2);
230 cycle->n_elems = 2; /* initial number of elements is 2 */
231 cycle->elems[0] = pairs[start].in_reg;
232 cycle->elems[1] = pairs[start].out_reg;
233 cycle->type = cycle_tp;
234 cur_idx = pairs[start].out_reg->index;
237 /* check for cycle or end of a chain */
238 while (cur_idx != head) {
239 /* goto next register in cycle or chain */
240 cur_pair_idx = get_pairidx_for_regidx(pairs, n, cur_idx, 0);
242 if (cur_pair_idx < 0)
245 cur_idx = pairs[cur_pair_idx].out_reg->index;
247 /* it's not the first element: insert it */
248 if (cur_idx != head) {
249 cycle->elems[idx++] = pairs[cur_pair_idx].out_reg;
253 /* we are there where we started -> CYCLE */
254 cycle->type = PERM_CYCLE;
258 /* mark all pairs having one in/out register with cycle in common as checked */
259 for (idx = 0; idx < cycle->n_elems; idx++) {
260 cur_pair_idx = get_pairidx_for_regidx(pairs, n, cycle->elems[idx]->index, 0);
262 if (cur_pair_idx >= 0)
263 pairs[cur_pair_idx].checked = 1;
265 cur_pair_idx = get_pairidx_for_regidx(pairs, n, cycle->elems[idx]->index, 1);
267 if (cur_pair_idx >= 0)
268 pairs[cur_pair_idx].checked = 1;
275 * Lowers a perm node. Resolves cycles and creates a bunch of
276 * copy and swap operations to permute registers.
277 * Note: The caller of this function has to make sure, that irn
280 * @param irn The perm node
281 * @param block The block the perm node belongs to
282 * @param walk_env The environment
284 static void lower_perm_node(ir_node *irn, void *walk_env) {
285 ir_graph *irg = get_irn_irg(irn);
286 const arch_register_class_t *reg_class;
287 lower_env_t *env = walk_env;
289 int n, i, pn, do_copy, j, n_ops;
291 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 do_copy = env->do_copy;
298 DEBUG_ONLY(mod = env->dbg_module;)
299 block = get_nodes_block(irn);
302 Get the schedule predecessor node to the perm
303 NOTE: This works with auto-magic. If we insert the
304 new copy/exchange nodes after this node, everything
307 sched_point = sched_prev(irn);
308 DBG((mod, LEVEL_1, "perm: %+F\n", 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(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(pairs[i].in_node);
326 pairs[i].out_reg = arch_get_irn_register(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 /* reroute the edges from the proj to the argument */
343 exchange(pairs[i].out_node, pairs[i].in_node);
345 pairs[i].checked = 1;
349 /* Set do_copy to 0 if it's on but we have no free register */
354 /* check for cycles and chains */
355 while (get_n_checked_pairs(pairs, n) < n) {
360 /* go to the first not-checked pair */
361 while (pairs[i].checked) i++;
362 cycle = XMALLOCZ(perm_cycle_t);
363 cycle = get_perm_cycle(cycle, pairs, n, i);
365 DB((mod, LEVEL_1, "%+F: following %s created:\n ", irn, cycle->type == PERM_CHAIN ? "chain" : "cycle"));
366 for (j = 0; j < cycle->n_elems; j++) {
367 DB((mod, LEVEL_1, " %s", cycle->elems[j]->name));
369 DB((mod, LEVEL_1, "\n"));
372 We don't need to do anything if we have a Perm with two
373 elements which represents a cycle, because those nodes
374 already represent exchange nodes
376 if (n == 2 && cycle->type == PERM_CYCLE) {
382 //TODO: - iff PERM_CYCLE && do_copy -> determine free temp reg and insert copy to/from it before/after
383 // the copy cascade (this reduces the cycle into a chain)
385 /* build copy/swap nodes from back to front */
386 for (i = cycle->n_elems - 2; i >= 0; i--) {
387 arg1 = get_node_for_in_register(pairs, n, cycle->elems[i]);
388 arg2 = get_node_for_in_register(pairs, n, cycle->elems[i + 1]);
390 res1 = get_node_for_out_register(pairs, n, cycle->elems[i]);
391 res2 = get_node_for_out_register(pairs, n, cycle->elems[i + 1]);
393 If we have a cycle and don't copy: we need to create exchange nodes
394 NOTE: An exchange node is a perm node with 2 INs and 2 OUTs
395 IN_1 = in node with register i
396 IN_2 = in node with register i + 1
397 OUT_1 = out node with register i + 1
398 OUT_2 = out node with register i
400 if (cycle->type == PERM_CYCLE && !do_copy) {
404 /* At this point we have to handle the following problem: */
406 /* If we have a cycle with more than two elements, then */
407 /* this could correspond to the following Perm node: */
409 /* +----+ +----+ +----+ */
410 /* | r1 | | r2 | | r3 | */
411 /* +-+--+ +-+--+ +--+-+ */
414 /* +-+--------+---------+-+ */
416 /* +-+--------+---------+-+ */
419 /* +-+--+ +-+--+ +--+-+ */
420 /* |Proj| |Proj| |Proj| */
421 /* | r2 | | r3 | | r1 | */
422 /* +----+ +----+ +----+ */
424 /* This node is about to be split up into two 2x Perm's */
425 /* for which we need 4 Proj's and the one additional Proj */
426 /* of the first Perm has to be one IN of the second. So in */
427 /* general we need to create one additional Proj for each */
428 /* "middle" Perm and set this to one in node of the successor */
431 DBG((mod, LEVEL_1, "%+F creating exchange node (%+F, %s) and (%+F, %s) with\n",
432 irn, arg1, cycle->elems[i]->name, arg2, cycle->elems[i + 1]->name));
433 DBG((mod, LEVEL_1, "%+F (%+F, %s) and (%+F, %s)\n",
434 irn, res1, cycle->elems[i]->name, res2, cycle->elems[i + 1]->name));
436 cpyxchg = be_new_Perm(reg_class, irg, block, 2, in);
440 /* cycle is not done yet */
441 int pidx = get_pairidx_for_regidx(pairs, n, cycle->elems[i]->index, 0);
443 /* create intermediate proj */
444 res1 = new_r_Proj(irg, block, cpyxchg, get_irn_mode(res1), 0);
446 /* set as in for next Perm */
447 pairs[pidx].in_node = res1;
450 set_Proj_pred(res2, cpyxchg);
451 set_Proj_proj(res2, 0);
452 set_Proj_pred(res1, cpyxchg);
453 set_Proj_proj(res1, 1);
455 arch_set_irn_register(res2, cycle->elems[i + 1]);
456 arch_set_irn_register(res1, cycle->elems[i]);
458 /* insert the copy/exchange node in schedule after the magic schedule node (see above) */
459 sched_add_after(sched_point, cpyxchg);
461 DBG((mod, LEVEL_1, "replacing %+F with %+F, placed new node after %+F\n", irn, cpyxchg, sched_point));
463 /* set the new scheduling point */
467 DBG((mod, LEVEL_1, "%+F creating copy node (%+F, %s) -> (%+F, %s)\n",
468 irn, arg1, cycle->elems[i]->name, res2, cycle->elems[i + 1]->name));
470 cpyxchg = be_new_Copy(reg_class, irg, block, arg1);
471 arch_set_irn_register(cpyxchg, cycle->elems[i + 1]);
474 /* exchange copy node and proj */
475 exchange(res2, cpyxchg);
477 /* insert the copy/exchange node in schedule after the magic schedule node (see above) */
478 sched_add_after(sched_point, cpyxchg);
480 /* set the new scheduling point */
481 sched_point = cpyxchg;
485 free((void *) cycle->elems);
489 /* remove the perm from schedule */
498 static int has_irn_users(const ir_node *irn) {
499 return get_irn_out_edge_first_kind(irn, EDGE_KIND_NORMAL) != 0;
503 * Skip all Proj nodes.
505 static INLINE ir_node *belower_skip_proj(ir_node *irn) {
507 irn = get_Proj_pred(irn);
511 static ir_node *find_copy(ir_node *irn, ir_node *op)
515 for (cur_node = irn;;) {
516 cur_node = sched_prev(cur_node);
517 if (! be_is_Copy(cur_node))
519 if (be_get_Copy_op(cur_node) == op && arch_irn_is(cur_node, dont_spill))
524 static void gen_assure_different_pattern(ir_node *irn, ir_node *other_different, constraint_env_t *env) {
525 be_irg_t *birg = env->birg;
526 ir_graph *irg = be_get_birg_irg(birg);
527 ir_nodemap_t *op_set = &env->op_set;
528 ir_node *block = get_nodes_block(irn);
529 const arch_register_class_t *cls = arch_get_irn_reg_class(other_different, -1);
530 ir_node *in[2], *keep, *cpy;
531 op_copy_assoc_t *entry;
532 DEBUG_ONLY(firm_dbg_module_t *mod = env->dbg;)
534 if (arch_irn_is(other_different, ignore) ||
535 !mode_is_datab(get_irn_mode(other_different))) {
536 DBG((mod, LEVEL_1, "ignore constraint for %+F because other_irn is ignore or not a datab node\n", irn));
540 /* Make a not spillable copy of the different node */
541 /* this is needed because the different irn could be */
542 /* in block far far away */
543 /* The copy is optimized later if not needed */
545 /* check if already exists such a copy in the schedule immediately before */
546 cpy = find_copy(belower_skip_proj(irn), other_different);
548 cpy = be_new_Copy(cls, irg, block, other_different);
549 be_node_set_flags(cpy, BE_OUT_POS(0), arch_irn_flags_dont_spill);
550 DBG((mod, LEVEL_1, "created non-spillable %+F for value %+F\n", cpy, other_different));
553 DBG((mod, LEVEL_1, "using already existing %+F for value %+F\n", cpy, other_different));
559 /* Add the Keep resp. CopyKeep and reroute the users */
560 /* of the other_different irn in case of CopyKeep. */
561 if (has_irn_users(other_different)) {
562 keep = be_new_CopyKeep_single(cls, irg, block, cpy, irn, get_irn_mode(other_different));
563 be_node_set_reg_class(keep, 1, cls);
566 keep = be_new_Keep(cls, irg, block, 2, in);
569 DBG((mod, LEVEL_1, "created %+F(%+F, %+F)\n\n", keep, irn, cpy));
571 /* insert copy and keep into schedule */
572 assert(sched_is_scheduled(irn) && "need schedule to assure constraints");
573 if (! sched_is_scheduled(cpy))
574 sched_add_before(belower_skip_proj(irn), cpy);
575 sched_add_after(irn, keep);
577 /* insert the other different and it's copies into the map */
578 entry = ir_nodemap_get(op_set, other_different);
580 entry = obstack_alloc(&env->obst, sizeof(*entry));
582 ir_nodeset_init(&entry->copies);
584 ir_nodemap_insert(op_set, other_different, entry);
588 ir_nodeset_insert(&entry->copies, cpy);
590 /* insert keep in case of CopyKeep */
591 if (be_is_CopyKeep(keep)) {
592 ir_nodeset_insert(&entry->copies, keep);
597 * Checks if node has a must_be_different constraint in output and adds a Keep
598 * then to assure the constraint.
600 * @param irn the node to check
601 * @param skipped_irn if irn is a Proj node, its predecessor, else irn
602 * @param env the constraint environment
604 static void assure_different_constraints(ir_node *irn, ir_node *skipped_irn, constraint_env_t *env) {
605 const arch_register_req_t *req = arch_get_register_req(irn, -1);
607 if (arch_register_req_is(req, must_be_different)) {
608 const unsigned other = req->other_different;
611 if (arch_register_req_is(req, should_be_same)) {
612 const unsigned same = req->other_same;
614 if (is_po2(other) && is_po2(same)) {
615 int idx_other = ntz(other);
616 int idx_same = ntz(same);
619 * We can safely ignore a should_be_same x must_be_different y
620 * IFF both inputs are equal!
622 if (get_irn_n(skipped_irn, idx_other) == get_irn_n(skipped_irn, idx_same)) {
627 for (i = 0; 1U << i <= other; ++i) {
628 if (other & (1U << i)) {
629 ir_node *different_from = get_irn_n(skipped_irn, i);
630 gen_assure_different_pattern(irn, different_from, env);
637 * Calls the functions to assure register constraints.
639 * @param block The block to be checked
640 * @param walk_env The walker environment
642 static void assure_constraints_walker(ir_node *block, void *walk_env) {
645 sched_foreach_reverse(block, irn) {
646 ir_mode *mode = get_irn_mode(irn);
648 if (mode == mode_T) {
649 const ir_edge_t *edge;
651 foreach_out_edge(irn, edge) {
652 ir_node *proj = get_edge_src_irn(edge);
654 mode = get_irn_mode(proj);
655 if (mode_is_datab(mode))
656 assure_different_constraints(proj, irn, walk_env);
658 } else if (mode_is_datab(mode)) {
659 assure_different_constraints(irn, irn, walk_env);
665 * Melt all copykeeps pointing to the same node
666 * (or Projs of the same node), copying the same operand.
668 static void melt_copykeeps(constraint_env_t *cenv) {
669 be_irg_t *birg = cenv->birg;
670 ir_graph *irg = be_get_birg_irg(birg);
671 ir_nodemap_iterator_t map_iter;
672 ir_nodemap_entry_t map_entry;
675 foreach_ir_nodemap(&cenv->op_set, map_entry, map_iter) {
676 op_copy_assoc_t *entry = map_entry.data;
680 ir_nodeset_iterator_t iter;
681 ir_node **ck_arr, **melt_arr;
685 /* collect all copykeeps */
687 foreach_ir_nodeset(&entry->copies, cp, iter) {
688 if (be_is_CopyKeep(cp)) {
689 obstack_grow(&obst, &cp, sizeof(cp));
692 #ifdef KEEP_ALIVE_COPYKEEP_HACK
694 set_irn_mode(cp, mode_ANY);
697 #endif /* KEEP_ALIVE_COPYKEEP_HACK */
700 /* compare each copykeep with all other copykeeps */
701 ck_arr = (ir_node **)obstack_finish(&obst);
702 for (idx = 0; idx < num_ck; ++idx) {
703 ir_node *ref, *ref_mode_T;
709 ir_node *sched_pt = NULL;
713 ref_mode_T = skip_Proj(get_irn_n(ref, 1));
714 obstack_grow(&obst, &ref, sizeof(ref));
716 DBG((cenv->dbg, LEVEL_1, "Trying to melt %+F:\n", ref));
718 /* check for copykeeps pointing to the same mode_T node as the reference copykeep */
719 for (j = 0; j < num_ck; ++j) {
720 ir_node *cur_ck = ck_arr[j];
722 if (j != idx && cur_ck && skip_Proj(get_irn_n(cur_ck, 1)) == ref_mode_T) {
723 obstack_grow(&obst, &cur_ck, sizeof(cur_ck));
724 ir_nodeset_remove(&entry->copies, cur_ck);
725 DBG((cenv->dbg, LEVEL_1, "\t%+F\n", cur_ck));
728 sched_remove(cur_ck);
733 /* check, if we found some candidates for melting */
735 DBG((cenv->dbg, LEVEL_1, "\tno candidate found\n"));
739 ir_nodeset_remove(&entry->copies, ref);
742 melt_arr = (ir_node **)obstack_finish(&obst);
743 /* melt all found copykeeps */
744 NEW_ARR_A(ir_node *, new_ck_in, n_melt);
745 for (j = 0; j < n_melt; ++j) {
746 new_ck_in[j] = get_irn_n(melt_arr[j], 1);
748 /* now, we can kill the melted keep, except the */
749 /* ref one, we still need some information */
750 if (melt_arr[j] != ref)
751 kill_node(melt_arr[j]);
754 #ifdef KEEP_ALIVE_COPYKEEP_HACK
755 new_ck = be_new_CopyKeep(entry->cls, irg, get_nodes_block(ref), be_get_CopyKeep_op(ref), n_melt, new_ck_in, mode_ANY);
758 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));
759 #endif /* KEEP_ALIVE_COPYKEEP_HACK */
761 /* set register class for all kept inputs */
762 for (j = 1; j <= n_melt; ++j)
763 be_node_set_reg_class(new_ck, j, entry->cls);
765 ir_nodeset_insert(&entry->copies, new_ck);
767 /* find scheduling point */
768 sched_pt = ref_mode_T;
770 /* just walk along the schedule until a non-Keep/CopyKeep node is found */
771 sched_pt = sched_next(sched_pt);
772 } while (be_is_Keep(sched_pt) || be_is_CopyKeep(sched_pt));
774 sched_add_before(sched_pt, new_ck);
775 DBG((cenv->dbg, LEVEL_1, "created %+F, scheduled before %+F\n", new_ck, sched_pt));
777 /* finally: kill the reference copykeep */
782 obstack_free(&obst, NULL);
787 * Walks over all nodes to assure register constraints.
789 * @param birg The birg structure containing the irg
791 void assure_constraints(be_irg_t *birg) {
792 ir_graph *irg = be_get_birg_irg(birg);
793 constraint_env_t cenv;
795 ir_nodemap_iterator_t map_iter;
796 ir_nodemap_entry_t map_entry;
797 FIRM_DBG_REGISTER(firm_dbg_module_t *mod, "firm.be.lower.constr");
799 DEBUG_ONLY(cenv.dbg = mod;)
801 ir_nodemap_init(&cenv.op_set);
802 obstack_init(&cenv.obst);
804 irg_block_walk_graph(irg, NULL, assure_constraints_walker, &cenv);
806 /* melt copykeeps, pointing to projs of */
807 /* the same mode_T node and keeping the */
809 melt_copykeeps(&cenv);
812 foreach_ir_nodemap(&cenv.op_set, map_entry, map_iter) {
813 op_copy_assoc_t *entry = map_entry.data;
816 ir_nodeset_iterator_t iter;
817 be_ssa_construction_env_t senv;
819 n = ir_nodeset_size(&entry->copies);
820 nodes = alloca(n * sizeof(nodes[0]));
822 /* put the node in an array */
823 DBG((mod, LEVEL_1, "introduce copies for %+F ", map_entry.node));
825 /* collect all copies */
827 foreach_ir_nodeset(&entry->copies, cp, iter) {
829 DB((mod, LEVEL_1, ", %+F ", cp));
832 DB((mod, LEVEL_1, "\n"));
834 /* introduce the copies for the operand and it's copies */
835 be_ssa_construction_init(&senv, birg);
836 be_ssa_construction_add_copy(&senv, map_entry.node);
837 be_ssa_construction_add_copies(&senv, nodes, n);
838 be_ssa_construction_fix_users(&senv, map_entry.node);
839 be_ssa_construction_destroy(&senv);
841 /* Could be that not all CopyKeeps are really needed, */
842 /* so we transform unnecessary ones into Keeps. */
843 foreach_ir_nodeset(&entry->copies, cp, iter) {
844 if (be_is_CopyKeep(cp) && get_irn_n_edges(cp) < 1) {
846 int n = get_irn_arity(cp);
848 keep = be_new_Keep(arch_get_irn_reg_class(cp, -1),
849 irg, get_nodes_block(cp), n, get_irn_in(cp) + 1);
850 sched_add_before(cp, keep);
852 /* Set all ins (including the block) of the CopyKeep BAD to keep the verifier happy. */
858 ir_nodeset_destroy(&entry->copies);
861 ir_nodemap_destroy(&cenv.op_set);
862 obstack_free(&cenv.obst, NULL);
863 be_liveness_invalidate(be_get_birg_liveness(birg));
868 * Push nodes that do not need to be permed through the Perm.
869 * This is commonly a reload cascade at block ends.
870 * @note This routine needs interference.
871 * @note Probably, we can implement it a little more efficient.
872 * Especially searching the frontier lazily might be better.
873 * @param perm The perm.
874 * @param data The walker data (lower_env_t).
875 * @return 1, if there is something left to perm over.
876 * 0, if removed the complete perm.
878 static int push_through_perm(ir_node *perm, void *data)
880 lower_env_t *env = data;
882 ir_graph *irg = get_irn_irg(perm);
883 ir_node *bl = get_nodes_block(perm);
885 int arity = get_irn_arity(perm);
888 bitset_t *moved = bitset_alloca(arity);
891 ir_node *frontier = bl;
892 FIRM_DBG_REGISTER(firm_dbg_module_t *mod, "firm.be.lower.permmove");
895 const ir_edge_t *edge;
896 ir_node *one_proj = NULL, *irn;
897 const arch_register_class_t *cls = NULL;
899 DBG((mod, LEVEL_1, "perm move %+F irg %+F\n", perm, irg));
901 /* get some Proj and find out the register class of that Proj. */
902 edge = get_irn_out_edge_first_kind(perm, EDGE_KIND_NORMAL);
903 one_proj = get_edge_src_irn(edge);
904 assert(is_Proj(one_proj));
905 cls = arch_get_irn_reg_class(one_proj, -1);
907 /* Find the point in the schedule after which the
908 * potentially movable nodes must be defined.
909 * A Perm will only be pushed up to first instruction
910 * which lets an operand of itself die.
911 * If we would allow to move the Perm above this instruction,
912 * the former dead operand would be live now at the point of
913 * the Perm, increasing the register pressure by one.
915 sched_foreach_reverse_from (sched_prev(perm), irn) {
916 for (i = get_irn_arity(irn) - 1; i >= 0; --i) {
917 ir_node *op = get_irn_n(irn, i);
918 if (arch_irn_consider_in_reg_alloc(cls, op) &&
919 !values_interfere(env->birg, op, one_proj)) {
927 DBG((mod, LEVEL_2, "\tfrontier: %+F\n", frontier));
929 node = sched_prev(perm);
931 while(!sched_is_begin(node)) {
932 const arch_register_req_t *req;
936 /* search if node is a INPUT of Perm */
937 foreach_out_edge(perm, edge) {
938 ir_node *out = get_edge_src_irn(edge);
939 int pn = get_Proj_proj(out);
940 ir_node *in = get_irn_n(perm, pn);
947 /* it wasn't an input to the perm, we can't do anything more */
950 if(!sched_comes_after(frontier, node))
952 if (arch_irn_is(node, modify_flags))
955 req = arch_get_register_req(get_Proj_pred(node),
956 -1 - get_Proj_proj(node));
958 req = arch_get_register_req(node, -1);
960 if(req->type != arch_register_req_type_normal)
962 for(i = get_irn_arity(node) - 1; i >= 0; --i) {
963 ir_node *opop = get_irn_n(node, i);
964 if (arch_irn_consider_in_reg_alloc(cls, opop)) {
971 DBG((mod, LEVEL_2, "\tmoving %+F after %+F, killing %+F\n", node, perm, proj));
973 /* move the movable node in front of the Perm */
975 sched_add_after(perm, node);
977 /* give it the proj's register */
978 arch_set_irn_register(node, arch_get_irn_register(proj));
980 /* reroute all users of the proj to the moved node. */
981 edges_reroute(proj, node, irg);
984 set_Proj_pred(proj, new_Bad());
987 bitset_set(moved, input);
990 node = sched_prev(node);
993 /* well, we could not push anything through the perm */
997 new_size = arity - n_moved;
1002 map = alloca(new_size * sizeof(map[0]));
1003 proj_map = alloca(arity * sizeof(proj_map[0]));
1004 memset(proj_map, -1, sizeof(proj_map[0]));
1006 for(i = 0; i < arity; ++i) {
1007 if(bitset_is_set(moved, i))
1013 assert(n == new_size);
1014 foreach_out_edge(perm, edge) {
1015 ir_node *proj = get_edge_src_irn(edge);
1016 int pn = get_Proj_proj(proj);
1019 set_Proj_proj(proj, pn);
1022 be_Perm_reduce(perm, new_size, map);
1027 * Calls the corresponding lowering function for the node.
1029 * @param irn The node to be checked for lowering
1030 * @param walk_env The walker environment
1032 static void lower_nodes_after_ra_walker(ir_node *irn, void *walk_env)
1036 if (!be_is_Perm(irn))
1039 perm_stayed = push_through_perm(irn, walk_env);
1043 lower_perm_node(irn, walk_env);
1047 * Walks over all blocks in an irg and performs lowering need to be
1048 * done after register allocation (e.g. perm lowering).
1050 * @param birg The birg object
1051 * @param do_copy 1 == resolve cycles with a free reg if available
1053 void lower_nodes_after_ra(be_irg_t *birg, int do_copy) {
1055 ir_graph *irg = be_get_birg_irg(birg);
1058 env.do_copy = do_copy;
1059 FIRM_DBG_REGISTER(env.dbg_module, "firm.be.lower");
1061 /* we will need interference */
1062 be_liveness_assure_chk(be_get_birg_liveness(birg));
1064 irg_walk_blkwise_graph(irg, NULL, lower_nodes_after_ra_walker, &env);