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 Preference Guided Register Assignment
23 * @author Matthias Braun
27 * The idea is to allocate registers in 2 passes:
28 * 1. A first pass to determine "preferred" registers for live-ranges. This
29 * calculates for each register and each live-range a value indicating
30 * the usefulness. (You can roughly think of the value as the negative
31 * costs needed for copies when the value is in the specific registers...)
33 * 2. Walk blocks and assigns registers in a greedy fashion. Preferring
34 * registers with high preferences. When register constraints are not met,
35 * add copies and split live-ranges.
38 * - make use of free registers in the permute_values code
50 #include "iredges_t.h"
51 #include "irgraph_t.h"
57 #include "raw_bitset.h"
58 #include "unionfind.h"
60 #include "hungarian.h"
63 #include "bechordal_t.h"
72 #include "bespillutil.h"
76 #define USE_FACTOR 1.0f
77 #define DEF_FACTOR 1.0f
78 #define NEIGHBOR_FACTOR 0.2f
79 #define AFF_SHOULD_BE_SAME 0.5f
81 #define SPLIT_DELTA 1.0f
82 #define MAX_OPTIMISTIC_SPLIT_RECURSION 0
84 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
86 static struct obstack obst;
88 static const arch_register_class_t *cls;
89 static const arch_register_req_t *default_cls_req;
91 static const ir_exec_freq *execfreqs;
92 static unsigned n_regs;
93 static unsigned *normal_regs;
94 static int *congruence_classes;
95 static ir_node **block_order;
96 static int n_block_order;
97 static int create_preferences = true;
98 static int create_congruence_classes = true;
99 static int propagate_phi_registers = true;
101 static const lc_opt_table_entry_t options[] = {
102 LC_OPT_ENT_BOOL("prefs", "use preference based coloring", &create_preferences),
103 LC_OPT_ENT_BOOL("congruences", "create congruence classes", &create_congruence_classes),
104 LC_OPT_ENT_BOOL("prop_phi", "propagate phi registers", &propagate_phi_registers),
108 /** currently active assignments (while processing a basic block)
109 * maps registers to values(their current copies) */
110 static ir_node **assignments;
113 * allocation information: last_uses, register preferences
114 * the information is per firm-node.
116 struct allocation_info_t {
117 unsigned last_uses[2]; /**< bitset indicating last uses (input pos) */
118 ir_node *current_value; /**< copy of the value that should be used */
119 ir_node *original_value; /**< for copies point to original value */
120 float prefs[0]; /**< register preferences */
122 typedef struct allocation_info_t allocation_info_t;
124 /** helper datastructure used when sorting register preferences */
129 typedef struct reg_pref_t reg_pref_t;
131 /** per basic-block information */
132 struct block_info_t {
133 bool processed; /**< indicate whether block is processed */
134 ir_node *assignments[0]; /**< register assignments at end of block */
136 typedef struct block_info_t block_info_t;
139 * Get the allocation info for a node.
140 * The info is allocated on the first visit of a node.
142 static allocation_info_t *get_allocation_info(ir_node *node)
144 allocation_info_t *info = get_irn_link(node);
146 info = OALLOCFZ(&obst, allocation_info_t, prefs, n_regs);
147 info->current_value = node;
148 info->original_value = node;
149 set_irn_link(node, info);
155 static allocation_info_t *try_get_allocation_info(const ir_node *node)
157 return (allocation_info_t*) get_irn_link(node);
161 * Get allocation information for a basic block
163 static block_info_t *get_block_info(ir_node *block)
165 block_info_t *info = get_irn_link(block);
167 assert(is_Block(block));
169 info = OALLOCFZ(&obst, block_info_t, assignments, n_regs);
170 set_irn_link(block, info);
177 * Get default register requirement for the current register class
179 static const arch_register_req_t *get_default_req_current_cls(void)
181 if (default_cls_req == NULL) {
182 struct obstack *obst = get_irg_obstack(irg);
183 arch_register_req_t *req = OALLOCZ(obst, arch_register_req_t);
185 req->type = arch_register_req_type_normal;
189 default_cls_req = req;
191 return default_cls_req;
195 * Link the allocation info of a node to a copy.
196 * Afterwards, both nodes uses the same allocation info.
197 * Copy must not have an allocation info assigned yet.
199 * @param copy the node that gets the allocation info assigned
200 * @param value the original node
202 static void mark_as_copy_of(ir_node *copy, ir_node *value)
205 allocation_info_t *info = get_allocation_info(value);
206 allocation_info_t *copy_info = get_allocation_info(copy);
208 /* find original value */
209 original = info->original_value;
210 if (original != value) {
211 info = get_allocation_info(original);
214 assert(info->original_value == original);
215 info->current_value = copy;
217 /* the copy should not be linked to something else yet */
218 assert(copy_info->original_value == copy);
219 copy_info->original_value = original;
221 /* copy over allocation preferences */
222 memcpy(copy_info->prefs, info->prefs, n_regs * sizeof(copy_info->prefs[0]));
226 * Calculate the penalties for every register on a node and its live neighbors.
228 * @param live_nodes the set of live nodes at the current position, may be NULL
229 * @param penalty the penalty to subtract from
230 * @param limited a raw bitset containing the limited set for the node
231 * @param node the node
233 static void give_penalties_for_limits(const ir_nodeset_t *live_nodes,
234 float penalty, const unsigned* limited,
237 ir_nodeset_iterator_t iter;
240 allocation_info_t *info = get_allocation_info(node);
243 /* give penalty for all forbidden regs */
244 for (r = 0; r < n_regs; ++r) {
245 if (rbitset_is_set(limited, r))
248 info->prefs[r] -= penalty;
251 /* all other live values should get a penalty for allowed regs */
252 if (live_nodes == NULL)
255 penalty *= NEIGHBOR_FACTOR;
256 n_allowed = rbitset_popcount(limited, n_regs);
258 /* only create a very weak penalty if multiple regs are allowed */
259 penalty = (penalty * 0.8f) / n_allowed;
261 foreach_ir_nodeset(live_nodes, neighbor, iter) {
262 allocation_info_t *neighbor_info;
264 /* TODO: if op is used on multiple inputs we might not do a
266 if (neighbor == node)
269 neighbor_info = get_allocation_info(neighbor);
270 for (r = 0; r < n_regs; ++r) {
271 if (!rbitset_is_set(limited, r))
274 neighbor_info->prefs[r] -= penalty;
280 * Calculate the preferences of a definition for the current register class.
281 * If the definition uses a limited set of registers, reduce the preferences
282 * for the limited register on the node and its neighbors.
284 * @param live_nodes the set of live nodes at the current node
285 * @param weight the weight
286 * @param node the current node
288 static void check_defs(const ir_nodeset_t *live_nodes, float weight,
291 const arch_register_req_t *req = arch_get_register_req_out(node);
292 if (req->type & arch_register_req_type_limited) {
293 const unsigned *limited = req->limited;
294 float penalty = weight * DEF_FACTOR;
295 give_penalties_for_limits(live_nodes, penalty, limited, node);
298 if (req->type & arch_register_req_type_should_be_same) {
299 ir_node *insn = skip_Proj(node);
300 allocation_info_t *info = get_allocation_info(node);
301 int arity = get_irn_arity(insn);
304 float factor = 1.0f / rbitset_popcount(&req->other_same, arity);
305 for (i = 0; i < arity; ++i) {
308 allocation_info_t *op_info;
310 if (!rbitset_is_set(&req->other_same, i))
313 op = get_irn_n(insn, i);
315 /* if we the value at the should_be_same input doesn't die at the
316 * node, then it is no use to propagate the constraints (since a
317 * copy will emerge anyway) */
318 if (ir_nodeset_contains(live_nodes, op))
321 op_info = get_allocation_info(op);
322 for (r = 0; r < n_regs; ++r) {
323 op_info->prefs[r] += info->prefs[r] * factor;
330 * Walker: Runs an a block calculates the preferences for any
331 * node and every register from the considered register class.
333 static void analyze_block(ir_node *block, void *data)
335 float weight = (float)get_block_execfreq(execfreqs, block);
336 ir_nodeset_t live_nodes;
340 ir_nodeset_init(&live_nodes);
341 be_liveness_end_of_block(lv, cls, block, &live_nodes);
343 sched_foreach_reverse(block, node) {
344 allocation_info_t *info;
351 if (create_preferences) {
353 be_foreach_definition(node, cls, value,
354 check_defs(&live_nodes, weight, value);
359 arity = get_irn_arity(node);
361 /* the allocation info node currently only uses 1 unsigned value
362 to mark last used inputs. So we will fail for a node with more than
364 if (arity >= (int) sizeof(info->last_uses) * 8) {
365 panic("Node with more than %d inputs not supported yet",
366 (int) sizeof(info->last_uses) * 8);
369 info = get_allocation_info(node);
370 for (i = 0; i < arity; ++i) {
371 ir_node *op = get_irn_n(node, i);
372 if (!arch_irn_consider_in_reg_alloc(cls, op))
375 /* last usage of a value? */
376 if (!ir_nodeset_contains(&live_nodes, op)) {
377 rbitset_set(info->last_uses, i);
381 be_liveness_transfer(cls, node, &live_nodes);
383 if (create_preferences) {
384 /* update weights based on usage constraints */
385 for (i = 0; i < arity; ++i) {
386 const arch_register_req_t *req;
387 const unsigned *limited;
388 ir_node *op = get_irn_n(node, i);
390 if (!arch_irn_consider_in_reg_alloc(cls, op))
393 req = arch_get_register_req(node, i);
394 if (!(req->type & arch_register_req_type_limited))
397 limited = req->limited;
398 give_penalties_for_limits(&live_nodes, weight * USE_FACTOR,
404 ir_nodeset_destroy(&live_nodes);
407 static void congruence_def(ir_nodeset_t *live_nodes, const ir_node *node)
409 const arch_register_req_t *req = arch_get_register_req_out(node);
411 /* should be same constraint? */
412 if (req->type & arch_register_req_type_should_be_same) {
413 const ir_node *insn = skip_Proj_const(node);
414 int arity = get_irn_arity(insn);
416 unsigned node_idx = get_irn_idx(node);
417 node_idx = uf_find(congruence_classes, node_idx);
419 for (i = 0; i < arity; ++i) {
423 ir_nodeset_iterator_t iter;
424 bool interferes = false;
426 if (!rbitset_is_set(&req->other_same, i))
429 op = get_irn_n(insn, i);
430 op_idx = get_irn_idx(op);
431 op_idx = uf_find(congruence_classes, op_idx);
433 /* do we interfere with the value */
434 foreach_ir_nodeset(live_nodes, live, iter) {
435 int lv_idx = get_irn_idx(live);
436 lv_idx = uf_find(congruence_classes, lv_idx);
437 if (lv_idx == op_idx) {
442 /* don't put in same affinity class if we interfere */
446 node_idx = uf_union(congruence_classes, node_idx, op_idx);
447 DB((dbg, LEVEL_3, "Merge %+F and %+F congruence classes\n",
449 /* one should_be_same is enough... */
455 static void create_congruence_class(ir_node *block, void *data)
457 ir_nodeset_t live_nodes;
461 ir_nodeset_init(&live_nodes);
462 be_liveness_end_of_block(lv, cls, block, &live_nodes);
464 /* check should be same constraints */
465 sched_foreach_reverse(block, node) {
470 be_foreach_definition(node, cls, value,
471 congruence_def(&live_nodes, value);
473 be_liveness_transfer(cls, node, &live_nodes);
476 /* check phi congruence classes */
477 sched_foreach_reverse_from(node, node) {
481 assert(is_Phi(node));
483 if (!arch_irn_consider_in_reg_alloc(cls, node))
486 node_idx = get_irn_idx(node);
487 node_idx = uf_find(congruence_classes, node_idx);
489 arity = get_irn_arity(node);
490 for (i = 0; i < arity; ++i) {
491 bool interferes = false;
492 ir_nodeset_iterator_t iter;
497 allocation_info_t *head_info;
498 allocation_info_t *other_info;
499 ir_node *op = get_Phi_pred(node, i);
500 int op_idx = get_irn_idx(op);
501 op_idx = uf_find(congruence_classes, op_idx);
503 /* do we interfere with the value */
504 foreach_ir_nodeset(&live_nodes, live, iter) {
505 int lv_idx = get_irn_idx(live);
506 lv_idx = uf_find(congruence_classes, lv_idx);
507 if (lv_idx == op_idx) {
512 /* don't put in same affinity class if we interfere */
515 /* any other phi has the same input? */
516 sched_foreach(block, phi) {
521 if (!arch_irn_consider_in_reg_alloc(cls, phi))
523 oop = get_Phi_pred(phi, i);
526 oop_idx = get_irn_idx(oop);
527 oop_idx = uf_find(congruence_classes, oop_idx);
528 if (oop_idx == op_idx) {
536 /* merge the 2 congruence classes and sum up their preferences */
537 old_node_idx = node_idx;
538 node_idx = uf_union(congruence_classes, node_idx, op_idx);
539 DB((dbg, LEVEL_3, "Merge %+F and %+F congruence classes\n",
542 old_node_idx = node_idx == old_node_idx ? op_idx : old_node_idx;
543 head_info = get_allocation_info(get_idx_irn(irg, node_idx));
544 other_info = get_allocation_info(get_idx_irn(irg, old_node_idx));
545 for (r = 0; r < n_regs; ++r) {
546 head_info->prefs[r] += other_info->prefs[r];
552 static void set_congruence_prefs(ir_node *node, void *data)
554 allocation_info_t *info;
555 allocation_info_t *head_info;
556 unsigned node_idx = get_irn_idx(node);
557 unsigned node_set = uf_find(congruence_classes, node_idx);
561 /* head of congruence class or not in any class */
562 if (node_set == node_idx)
565 if (!arch_irn_consider_in_reg_alloc(cls, node))
568 head_info = get_allocation_info(get_idx_irn(irg, node_set));
569 info = get_allocation_info(node);
571 memcpy(info->prefs, head_info->prefs, n_regs * sizeof(info->prefs[0]));
574 static void combine_congruence_classes(void)
576 size_t n = get_irg_last_idx(irg);
577 congruence_classes = XMALLOCN(int, n);
578 uf_init(congruence_classes, n);
580 /* create congruence classes */
581 irg_block_walk_graph(irg, create_congruence_class, NULL, NULL);
582 /* merge preferences */
583 irg_walk_graph(irg, set_congruence_prefs, NULL, NULL);
584 free(congruence_classes);
590 * Assign register reg to the given node.
592 * @param node the node
593 * @param reg the register
595 static void use_reg(ir_node *node, const arch_register_t *reg)
597 unsigned r = arch_register_get_index(reg);
598 assignments[r] = node;
599 arch_set_irn_register(node, reg);
602 static void free_reg_of_value(ir_node *node)
604 const arch_register_t *reg;
607 if (!arch_irn_consider_in_reg_alloc(cls, node))
610 reg = arch_get_irn_register(node);
611 r = arch_register_get_index(reg);
612 /* assignment->value may be NULL if a value is used at 2 inputs
613 so it gets freed twice. */
614 assert(assignments[r] == node || assignments[r] == NULL);
615 assignments[r] = NULL;
619 * Compare two register preferences in decreasing order.
621 static int compare_reg_pref(const void *e1, const void *e2)
623 const reg_pref_t *rp1 = (const reg_pref_t*) e1;
624 const reg_pref_t *rp2 = (const reg_pref_t*) e2;
625 if (rp1->pref < rp2->pref)
627 if (rp1->pref > rp2->pref)
632 static void fill_sort_candidates(reg_pref_t *regprefs,
633 const allocation_info_t *info)
637 for (r = 0; r < n_regs; ++r) {
638 float pref = info->prefs[r];
640 regprefs[r].pref = pref;
642 /* TODO: use a stable sort here to avoid unnecessary register jumping */
643 qsort(regprefs, n_regs, sizeof(regprefs[0]), compare_reg_pref);
646 static bool try_optimistic_split(ir_node *to_split, ir_node *before,
647 float pref, float pref_delta,
648 unsigned *forbidden_regs, int recursion)
650 const arch_register_t *from_reg;
651 const arch_register_t *reg;
652 ir_node *original_insn;
658 allocation_info_t *info = get_allocation_info(to_split);
661 float split_threshold;
665 /* stupid hack: don't optimisticallt split don't spill nodes...
666 * (so we don't split away the values produced because of
667 * must_be_different constraints) */
668 original_insn = skip_Proj(info->original_value);
669 if (arch_irn_get_flags(original_insn) & arch_irn_flags_dont_spill)
672 from_reg = arch_get_irn_register(to_split);
673 from_r = arch_register_get_index(from_reg);
674 block = get_nodes_block(before);
675 split_threshold = (float)get_block_execfreq(execfreqs, block) * SPLIT_DELTA;
677 if (pref_delta < split_threshold*0.5)
680 /* find the best free position where we could move to */
681 prefs = ALLOCAN(reg_pref_t, n_regs);
682 fill_sort_candidates(prefs, info);
683 for (i = 0; i < n_regs; ++i) {
687 bool old_source_state;
689 /* we need a normal register which is not an output register
690 an different from the current register of to_split */
692 if (!rbitset_is_set(normal_regs, r))
694 if (rbitset_is_set(forbidden_regs, r))
699 /* is the split worth it? */
700 delta = pref_delta + prefs[i].pref;
701 if (delta < split_threshold) {
702 DB((dbg, LEVEL_3, "Not doing optimistical split of %+F (depth %d), win %f too low\n",
703 to_split, recursion, delta));
707 /* if the register is free then we can do the split */
708 if (assignments[r] == NULL)
711 /* otherwise we might try recursively calling optimistic_split */
712 if (recursion+1 > MAX_OPTIMISTIC_SPLIT_RECURSION)
715 apref = prefs[i].pref;
716 apref_delta = i+1 < n_regs ? apref - prefs[i+1].pref : 0;
717 apref_delta += pref_delta - split_threshold;
719 /* our source register isn't a useful destination for recursive
721 old_source_state = rbitset_is_set(forbidden_regs, from_r);
722 rbitset_set(forbidden_regs, from_r);
723 /* try recursive split */
724 res = try_optimistic_split(assignments[r], before, apref,
725 apref_delta, forbidden_regs, recursion+1);
726 /* restore our destination */
727 if (old_source_state) {
728 rbitset_set(forbidden_regs, from_r);
730 rbitset_clear(forbidden_regs, from_r);
739 reg = arch_register_for_index(cls, r);
740 copy = be_new_Copy(cls, block, to_split);
741 mark_as_copy_of(copy, to_split);
742 /* hacky, but correct here */
743 if (assignments[arch_register_get_index(from_reg)] == to_split)
744 free_reg_of_value(to_split);
746 sched_add_before(before, copy);
749 "Optimistic live-range split %+F move %+F(%s) -> %s before %+F (win %f, depth %d)\n",
750 copy, to_split, from_reg->name, reg->name, before, delta, recursion));
755 * Determine and assign a register for node @p node
757 static void assign_reg(const ir_node *block, ir_node *node,
758 unsigned *forbidden_regs)
760 const arch_register_t *reg;
761 allocation_info_t *info;
762 const arch_register_req_t *req;
763 reg_pref_t *reg_prefs;
766 const unsigned *allowed_regs;
769 assert(!is_Phi(node));
770 assert(arch_irn_consider_in_reg_alloc(cls, node));
772 /* preassigned register? */
773 reg = arch_get_irn_register(node);
775 DB((dbg, LEVEL_2, "Preassignment %+F -> %s\n", node, reg->name));
780 /* give should_be_same boni */
781 info = get_allocation_info(node);
782 req = arch_get_register_req_out(node);
784 in_node = skip_Proj(node);
785 if (req->type & arch_register_req_type_should_be_same) {
786 float weight = (float)get_block_execfreq(execfreqs, block);
787 int arity = get_irn_arity(in_node);
790 assert(arity <= (int) sizeof(req->other_same) * 8);
791 for (i = 0; i < arity; ++i) {
793 const arch_register_t *reg;
795 if (!rbitset_is_set(&req->other_same, i))
798 in = get_irn_n(in_node, i);
799 reg = arch_get_irn_register(in);
801 r = arch_register_get_index(reg);
803 /* if the value didn't die here then we should not propagate the
804 * should_be_same info */
805 if (assignments[r] == in)
808 info->prefs[r] += weight * AFF_SHOULD_BE_SAME;
812 /* create list of register candidates and sort by their preference */
813 DB((dbg, LEVEL_2, "Candidates for %+F:", node));
814 reg_prefs = alloca(n_regs * sizeof(reg_prefs[0]));
815 fill_sort_candidates(reg_prefs, info);
816 for (i = 0; i < n_regs; ++i) {
817 unsigned num = reg_prefs[i].num;
818 const arch_register_t *reg;
820 if (!rbitset_is_set(normal_regs, num))
823 reg = arch_register_for_index(cls, num);
824 DB((dbg, LEVEL_2, " %s(%f)", reg->name, reg_prefs[i].pref));
826 DB((dbg, LEVEL_2, "\n"));
828 allowed_regs = normal_regs;
829 if (req->type & arch_register_req_type_limited) {
830 allowed_regs = req->limited;
833 for (i = 0; i < n_regs; ++i) {
838 r = reg_prefs[i].num;
839 if (!rbitset_is_set(allowed_regs, r))
841 if (assignments[r] == NULL)
843 pref = reg_prefs[i].pref;
844 delta = i+1 < n_regs ? pref - reg_prefs[i+1].pref : 0;
845 before = skip_Proj(node);
846 res = try_optimistic_split(assignments[r], before,
847 pref, delta, forbidden_regs, 0);
852 /* the common reason to hit this panic is when 1 of your nodes is not
853 * register pressure faithful */
854 panic("No register left for %+F\n", node);
857 reg = arch_register_for_index(cls, r);
858 DB((dbg, LEVEL_2, "Assign %+F -> %s\n", node, reg->name));
863 * Add an permutation in front of a node and change the assignments
864 * due to this permutation.
866 * To understand this imagine a permutation like this:
876 * First we count how many destinations a single value has. At the same time
877 * we can be sure that each destination register has at most 1 source register
878 * (it can have 0 which means we don't care what value is in it).
879 * We ignore all fullfilled permuations (like 7->7)
880 * In a first pass we create as much copy instructions as possible as they
881 * are generally cheaper than exchanges. We do this by counting into how many
882 * destinations a register has to be copied (in the example it's 2 for register
883 * 3, or 1 for the registers 1,2,4 and 7).
884 * We can then create a copy into every destination register when the usecount
885 * of that register is 0 (= noone else needs the value in the register).
887 * After this step we should have cycles left. We implement a cyclic permutation
888 * of n registers with n-1 transpositions.
890 * @param live_nodes the set of live nodes, updated due to live range split
891 * @param before the node before we add the permutation
892 * @param permutation the permutation array indices are the destination
893 * registers, the values in the array are the source
896 static void permute_values(ir_nodeset_t *live_nodes, ir_node *before,
897 unsigned *permutation)
899 unsigned *n_used = ALLOCANZ(unsigned, n_regs);
903 /* determine how often each source register needs to be read */
904 for (r = 0; r < n_regs; ++r) {
905 unsigned old_reg = permutation[r];
908 value = assignments[old_reg];
910 /* nothing to do here, reg is not live. Mark it as fixpoint
911 * so we ignore it in the next steps */
919 block = get_nodes_block(before);
921 /* step1: create copies where immediately possible */
922 for (r = 0; r < n_regs; /* empty */) {
925 const arch_register_t *reg;
926 unsigned old_r = permutation[r];
928 /* - no need to do anything for fixed points.
929 - we can't copy if the value in the dest reg is still needed */
930 if (old_r == r || n_used[r] > 0) {
936 src = assignments[old_r];
937 copy = be_new_Copy(cls, block, src);
938 sched_add_before(before, copy);
939 reg = arch_register_for_index(cls, r);
940 DB((dbg, LEVEL_2, "Copy %+F (from %+F, before %+F) -> %s\n",
941 copy, src, before, reg->name));
942 mark_as_copy_of(copy, src);
945 if (live_nodes != NULL) {
946 ir_nodeset_insert(live_nodes, copy);
949 /* old register has 1 user less, permutation is resolved */
950 assert(arch_register_get_index(arch_get_irn_register(src)) == old_r);
953 assert(n_used[old_r] > 0);
955 if (n_used[old_r] == 0) {
956 if (live_nodes != NULL) {
957 ir_nodeset_remove(live_nodes, src);
959 free_reg_of_value(src);
962 /* advance or jump back (if this copy enabled another copy) */
963 if (old_r < r && n_used[old_r] == 0) {
970 /* at this point we only have "cycles" left which we have to resolve with
972 * TODO: if we have free registers left, then we should really use copy
973 * instructions for any cycle longer than 2 registers...
974 * (this is probably architecture dependent, there might be archs where
975 * copies are preferable even for 2-cycles) */
977 /* create perms with the rest */
978 for (r = 0; r < n_regs; /* empty */) {
979 const arch_register_t *reg;
980 unsigned old_r = permutation[r];
992 /* we shouldn't have copies from 1 value to multiple destinations left*/
993 assert(n_used[old_r] == 1);
995 /* exchange old_r and r2; after that old_r is a fixed point */
996 r2 = permutation[old_r];
998 in[0] = assignments[r2];
999 in[1] = assignments[old_r];
1000 perm = be_new_Perm(cls, block, 2, in);
1001 sched_add_before(before, perm);
1002 DB((dbg, LEVEL_2, "Perm %+F (perm %+F,%+F, before %+F)\n",
1003 perm, in[0], in[1], before));
1005 proj0 = new_r_Proj(perm, get_irn_mode(in[0]), 0);
1006 mark_as_copy_of(proj0, in[0]);
1007 reg = arch_register_for_index(cls, old_r);
1008 use_reg(proj0, reg);
1010 proj1 = new_r_Proj(perm, get_irn_mode(in[1]), 1);
1011 mark_as_copy_of(proj1, in[1]);
1012 reg = arch_register_for_index(cls, r2);
1013 use_reg(proj1, reg);
1015 /* 1 value is now in the correct register */
1016 permutation[old_r] = old_r;
1017 /* the source of r changed to r2 */
1018 permutation[r] = r2;
1020 /* if we have reached a fixpoint update data structures */
1021 if (live_nodes != NULL) {
1022 ir_nodeset_remove(live_nodes, in[0]);
1023 ir_nodeset_remove(live_nodes, in[1]);
1024 ir_nodeset_remove(live_nodes, proj0);
1025 ir_nodeset_insert(live_nodes, proj1);
1029 #ifdef DEBUG_libfirm
1030 /* now we should only have fixpoints left */
1031 for (r = 0; r < n_regs; ++r) {
1032 assert(permutation[r] == r);
1038 * Free regs for values last used.
1040 * @param live_nodes set of live nodes, will be updated
1041 * @param node the node to consider
1043 static void free_last_uses(ir_nodeset_t *live_nodes, ir_node *node)
1045 allocation_info_t *info = get_allocation_info(node);
1046 const unsigned *last_uses = info->last_uses;
1047 int arity = get_irn_arity(node);
1050 for (i = 0; i < arity; ++i) {
1053 /* check if one operand is the last use */
1054 if (!rbitset_is_set(last_uses, i))
1057 op = get_irn_n(node, i);
1058 free_reg_of_value(op);
1059 ir_nodeset_remove(live_nodes, op);
1064 * change inputs of a node to the current value (copies/perms)
1066 static void rewire_inputs(ir_node *node)
1069 int arity = get_irn_arity(node);
1071 for (i = 0; i < arity; ++i) {
1072 ir_node *op = get_irn_n(node, i);
1073 allocation_info_t *info = try_get_allocation_info(op);
1078 info = get_allocation_info(info->original_value);
1079 if (info->current_value != op) {
1080 set_irn_n(node, i, info->current_value);
1086 * Create a bitset of registers occupied with value living through an
1089 static void determine_live_through_regs(unsigned *bitset, ir_node *node)
1091 const allocation_info_t *info = get_allocation_info(node);
1096 /* mark all used registers as potentially live-through */
1097 for (r = 0; r < n_regs; ++r) {
1098 if (assignments[r] == NULL)
1100 if (!rbitset_is_set(normal_regs, r))
1103 rbitset_set(bitset, r);
1106 /* remove registers of value dying at the instruction */
1107 arity = get_irn_arity(node);
1108 for (i = 0; i < arity; ++i) {
1110 const arch_register_t *reg;
1112 if (!rbitset_is_set(info->last_uses, i))
1115 op = get_irn_n(node, i);
1116 reg = arch_get_irn_register(op);
1117 rbitset_clear(bitset, arch_register_get_index(reg));
1122 * Enforce constraints at a node by live range splits.
1124 * @param live_nodes the set of live nodes, might be changed
1125 * @param node the current node
1127 static void enforce_constraints(ir_nodeset_t *live_nodes, ir_node *node,
1128 unsigned *forbidden_regs)
1130 int arity = get_irn_arity(node);
1132 hungarian_problem_t *bp;
1134 unsigned *assignment;
1137 /* construct a list of register occupied by live-through values */
1138 unsigned *live_through_regs = NULL;
1140 /* see if any use constraints are not met */
1142 for (i = 0; i < arity; ++i) {
1143 ir_node *op = get_irn_n(node, i);
1144 const arch_register_t *reg;
1145 const arch_register_req_t *req;
1146 const unsigned *limited;
1149 if (!arch_irn_consider_in_reg_alloc(cls, op))
1152 /* are there any limitations for the i'th operand? */
1153 req = arch_get_register_req(node, i);
1154 if (!(req->type & arch_register_req_type_limited))
1157 limited = req->limited;
1158 reg = arch_get_irn_register(op);
1159 r = arch_register_get_index(reg);
1160 if (!rbitset_is_set(limited, r)) {
1161 /* found an assignment outside the limited set */
1167 /* is any of the live-throughs using a constrained output register? */
1168 be_foreach_definition(node, cls, value,
1169 if (! (req_->type & arch_register_req_type_limited))
1171 if (live_through_regs == NULL) {
1172 rbitset_alloca(live_through_regs, n_regs);
1173 determine_live_through_regs(live_through_regs, node);
1175 rbitset_or(forbidden_regs, req_->limited, n_regs);
1176 if (rbitsets_have_common(req_->limited, live_through_regs, n_regs))
1183 /* create these arrays if we haven't yet */
1184 if (live_through_regs == NULL) {
1185 rbitset_alloca(live_through_regs, n_regs);
1188 /* at this point we have to construct a bipartite matching problem to see
1189 * which values should go to which registers
1190 * Note: We're building the matrix in "reverse" - source registers are
1191 * right, destinations left because this will produce the solution
1192 * in the format required for permute_values.
1194 bp = hungarian_new(n_regs, n_regs, HUNGARIAN_MATCH_PERFECT);
1196 /* add all combinations, then remove not allowed ones */
1197 for (l = 0; l < n_regs; ++l) {
1198 if (!rbitset_is_set(normal_regs, l)) {
1199 hungarian_add(bp, l, l, 1);
1203 for (r = 0; r < n_regs; ++r) {
1204 if (!rbitset_is_set(normal_regs, r))
1206 /* livethrough values may not use constrainted output registers */
1207 if (rbitset_is_set(live_through_regs, l)
1208 && rbitset_is_set(forbidden_regs, r))
1211 hungarian_add(bp, r, l, l == r ? 9 : 8);
1215 for (i = 0; i < arity; ++i) {
1216 ir_node *op = get_irn_n(node, i);
1217 const arch_register_t *reg;
1218 const arch_register_req_t *req;
1219 const unsigned *limited;
1220 unsigned current_reg;
1222 if (!arch_irn_consider_in_reg_alloc(cls, op))
1225 req = arch_get_register_req(node, i);
1226 if (!(req->type & arch_register_req_type_limited))
1229 limited = req->limited;
1230 reg = arch_get_irn_register(op);
1231 current_reg = arch_register_get_index(reg);
1232 for (r = 0; r < n_regs; ++r) {
1233 if (rbitset_is_set(limited, r))
1235 hungarian_remove(bp, r, current_reg);
1239 //hungarian_print_cost_matrix(bp, 1);
1240 hungarian_prepare_cost_matrix(bp, HUNGARIAN_MODE_MAXIMIZE_UTIL);
1242 assignment = ALLOCAN(unsigned, n_regs);
1243 res = hungarian_solve(bp, assignment, NULL, 0);
1247 fprintf(stderr, "Swap result:");
1248 for (i = 0; i < (int) n_regs; ++i) {
1249 fprintf(stderr, " %d", assignment[i]);
1251 fprintf(stderr, "\n");
1256 permute_values(live_nodes, node, assignment);
1259 /** test wether a node @p n is a copy of the value of node @p of */
1260 static bool is_copy_of(ir_node *value, ir_node *test_value)
1262 allocation_info_t *test_info;
1263 allocation_info_t *info;
1265 if (value == test_value)
1268 info = get_allocation_info(value);
1269 test_info = get_allocation_info(test_value);
1270 return test_info->original_value == info->original_value;
1274 * find a value in the end-assignment of a basic block
1275 * @returns the index into the assignment array if found
1278 static int find_value_in_block_info(block_info_t *info, ir_node *value)
1281 ir_node **assignments = info->assignments;
1282 for (r = 0; r < n_regs; ++r) {
1283 ir_node *a_value = assignments[r];
1285 if (a_value == NULL)
1287 if (is_copy_of(a_value, value))
1295 * Create the necessary permutations at the end of a basic block to fullfill
1296 * the register assignment for phi-nodes in the next block
1298 static void add_phi_permutations(ir_node *block, int p)
1301 unsigned *permutation;
1302 ir_node **old_assignments;
1303 bool need_permutation;
1305 ir_node *pred = get_Block_cfgpred_block(block, p);
1307 block_info_t *pred_info = get_block_info(pred);
1309 /* predecessor not processed yet? nothing to do */
1310 if (!pred_info->processed)
1313 permutation = ALLOCAN(unsigned, n_regs);
1314 for (r = 0; r < n_regs; ++r) {
1318 /* check phi nodes */
1319 need_permutation = false;
1320 node = sched_first(block);
1321 for ( ; is_Phi(node); node = sched_next(node)) {
1322 const arch_register_t *reg;
1327 if (!arch_irn_consider_in_reg_alloc(cls, node))
1330 op = get_Phi_pred(node, p);
1331 if (!arch_irn_consider_in_reg_alloc(cls, op))
1334 a = find_value_in_block_info(pred_info, op);
1337 reg = arch_get_irn_register(node);
1338 regn = arch_register_get_index(reg);
1340 permutation[regn] = a;
1341 need_permutation = true;
1345 if (need_permutation) {
1346 /* permute values at end of predecessor */
1347 old_assignments = assignments;
1348 assignments = pred_info->assignments;
1349 permute_values(NULL, be_get_end_of_block_insertion_point(pred),
1351 assignments = old_assignments;
1354 /* change phi nodes to use the copied values */
1355 node = sched_first(block);
1356 for ( ; is_Phi(node); node = sched_next(node)) {
1360 if (!arch_irn_consider_in_reg_alloc(cls, node))
1363 op = get_Phi_pred(node, p);
1364 /* no need to do anything for Unknown inputs */
1365 if (!arch_irn_consider_in_reg_alloc(cls, op))
1368 /* we have permuted all values into the correct registers so we can
1369 simply query which value occupies the phis register in the
1371 a = arch_register_get_index(arch_get_irn_register(node));
1372 op = pred_info->assignments[a];
1373 set_Phi_pred(node, p, op);
1378 * Set preferences for a phis register based on the registers used on the
1381 static void adapt_phi_prefs(ir_node *phi)
1384 int arity = get_irn_arity(phi);
1385 ir_node *block = get_nodes_block(phi);
1386 allocation_info_t *info = get_allocation_info(phi);
1388 for (i = 0; i < arity; ++i) {
1389 ir_node *op = get_irn_n(phi, i);
1390 const arch_register_t *reg = arch_get_irn_register(op);
1391 ir_node *pred_block;
1392 block_info_t *pred_block_info;
1398 /* we only give the bonus if the predecessor already has registers
1399 * assigned, otherwise we only see a dummy value
1400 * and any conclusions about its register are useless */
1401 pred_block = get_Block_cfgpred_block(block, i);
1402 pred_block_info = get_block_info(pred_block);
1403 if (!pred_block_info->processed)
1406 /* give bonus for already assigned register */
1407 weight = (float)get_block_execfreq(execfreqs, pred_block);
1408 r = arch_register_get_index(reg);
1409 info->prefs[r] += weight * AFF_PHI;
1414 * After a phi has been assigned a register propagate preference inputs
1415 * to the phi inputs.
1417 static void propagate_phi_register(ir_node *phi, unsigned assigned_r)
1420 ir_node *block = get_nodes_block(phi);
1421 int arity = get_irn_arity(phi);
1423 for (i = 0; i < arity; ++i) {
1424 ir_node *op = get_Phi_pred(phi, i);
1425 allocation_info_t *info = get_allocation_info(op);
1426 ir_node *pred_block = get_Block_cfgpred_block(block, i);
1429 = (float)get_block_execfreq(execfreqs, pred_block) * AFF_PHI;
1431 if (info->prefs[assigned_r] >= weight)
1434 /* promote the prefered register */
1435 for (r = 0; r < n_regs; ++r) {
1436 if (info->prefs[r] > -weight) {
1437 info->prefs[r] = -weight;
1440 info->prefs[assigned_r] = weight;
1443 propagate_phi_register(op, assigned_r);
1447 static void assign_phi_registers(ir_node *block)
1452 unsigned *assignment;
1454 hungarian_problem_t *bp;
1456 /* count phi nodes */
1457 sched_foreach(block, node) {
1460 if (!arch_irn_consider_in_reg_alloc(cls, node))
1468 /* build a bipartite matching problem for all phi nodes */
1469 bp = hungarian_new(n_phis, n_regs, HUNGARIAN_MATCH_PERFECT);
1471 sched_foreach(block, node) {
1474 allocation_info_t *info;
1477 if (!arch_irn_consider_in_reg_alloc(cls, node))
1480 /* give boni for predecessor colorings */
1481 adapt_phi_prefs(node);
1482 /* add stuff to bipartite problem */
1483 info = get_allocation_info(node);
1484 DB((dbg, LEVEL_3, "Prefs for %+F: ", node));
1485 for (r = 0; r < n_regs; ++r) {
1488 if (!rbitset_is_set(normal_regs, r))
1491 costs = info->prefs[r];
1492 costs = costs < 0 ? -logf(-costs+1) : logf(costs+1);
1495 hungarian_add(bp, n, r, (int)costs);
1496 DB((dbg, LEVEL_3, " %s(%f)", arch_register_for_index(cls, r)->name,
1499 DB((dbg, LEVEL_3, "\n"));
1503 //hungarian_print_cost_matrix(bp, 7);
1504 hungarian_prepare_cost_matrix(bp, HUNGARIAN_MODE_MAXIMIZE_UTIL);
1506 assignment = ALLOCAN(unsigned, n_regs);
1507 res = hungarian_solve(bp, assignment, NULL, 0);
1512 sched_foreach(block, node) {
1514 const arch_register_t *reg;
1518 if (!arch_irn_consider_in_reg_alloc(cls, node))
1521 r = assignment[n++];
1522 assert(rbitset_is_set(normal_regs, r));
1523 reg = arch_register_for_index(cls, r);
1524 DB((dbg, LEVEL_2, "Assign %+F -> %s\n", node, reg->name));
1527 /* adapt preferences for phi inputs */
1528 if (propagate_phi_registers)
1529 propagate_phi_register(node, r);
1534 * Walker: assign registers to all nodes of a block that
1535 * need registers from the currently considered register class.
1537 static void allocate_coalesce_block(ir_node *block, void *data)
1540 ir_nodeset_t live_nodes;
1543 block_info_t *block_info;
1544 block_info_t **pred_block_infos;
1546 unsigned *forbidden_regs; /**< collects registers which must
1547 not be used for optimistic splits */
1550 DB((dbg, LEVEL_2, "* Block %+F\n", block));
1552 /* clear assignments */
1553 block_info = get_block_info(block);
1554 assignments = block_info->assignments;
1556 ir_nodeset_init(&live_nodes);
1558 /* gather regalloc infos of predecessor blocks */
1559 n_preds = get_Block_n_cfgpreds(block);
1560 pred_block_infos = ALLOCAN(block_info_t*, n_preds);
1561 for (i = 0; i < n_preds; ++i) {
1562 ir_node *pred = get_Block_cfgpred_block(block, i);
1563 block_info_t *pred_info = get_block_info(pred);
1564 pred_block_infos[i] = pred_info;
1567 phi_ins = ALLOCAN(ir_node*, n_preds);
1569 /* collect live-in nodes and preassigned values */
1570 be_lv_foreach(lv, block, be_lv_state_in, i) {
1571 const arch_register_t *reg;
1573 bool need_phi = false;
1575 node = be_lv_get_irn(lv, block, i);
1576 if (!arch_irn_consider_in_reg_alloc(cls, node))
1579 /* check all predecessors for this value, if it is not everywhere the
1580 same or unknown then we have to construct a phi
1581 (we collect the potential phi inputs here) */
1582 for (p = 0; p < n_preds; ++p) {
1583 block_info_t *pred_info = pred_block_infos[p];
1585 if (!pred_info->processed) {
1586 /* use node for now, it will get fixed later */
1590 int a = find_value_in_block_info(pred_info, node);
1592 /* must live out of predecessor */
1594 phi_ins[p] = pred_info->assignments[a];
1595 /* different value from last time? then we need a phi */
1596 if (p > 0 && phi_ins[p-1] != phi_ins[p]) {
1603 ir_mode *mode = get_irn_mode(node);
1604 const arch_register_req_t *req = get_default_req_current_cls();
1607 phi = new_r_Phi(block, n_preds, phi_ins, mode);
1608 be_set_phi_reg_req(phi, req);
1610 DB((dbg, LEVEL_3, "Create Phi %+F (for %+F) -", phi, node));
1611 #ifdef DEBUG_libfirm
1614 for (i = 0; i < n_preds; ++i) {
1615 DB((dbg, LEVEL_3, " %+F", phi_ins[i]));
1617 DB((dbg, LEVEL_3, "\n"));
1620 mark_as_copy_of(phi, node);
1621 sched_add_after(block, phi);
1625 allocation_info_t *info = get_allocation_info(node);
1626 info->current_value = phi_ins[0];
1628 /* Grab 1 of the inputs we constructed (might not be the same as
1629 * "node" as we could see the same copy of the value in all
1634 /* if the node already has a register assigned use it */
1635 reg = arch_get_irn_register(node);
1640 /* remember that this node is live at the beginning of the block */
1641 ir_nodeset_insert(&live_nodes, node);
1644 rbitset_alloca(forbidden_regs, n_regs);
1646 /* handle phis... */
1647 assign_phi_registers(block);
1649 /* all live-ins must have a register */
1650 #ifdef DEBUG_libfirm
1652 ir_nodeset_iterator_t iter;
1653 foreach_ir_nodeset(&live_nodes, node, iter) {
1654 const arch_register_t *reg = arch_get_irn_register(node);
1655 assert(reg != NULL);
1660 /* assign instructions in the block */
1661 sched_foreach(block, node) {
1666 /* phis are already assigned */
1670 rewire_inputs(node);
1672 /* enforce use constraints */
1673 rbitset_clear_all(forbidden_regs, n_regs);
1674 enforce_constraints(&live_nodes, node, forbidden_regs);
1676 rewire_inputs(node);
1678 /* we may not use registers used for inputs for optimistic splits */
1679 arity = get_irn_arity(node);
1680 for (i = 0; i < arity; ++i) {
1681 ir_node *op = get_irn_n(node, i);
1682 const arch_register_t *reg;
1683 if (!arch_irn_consider_in_reg_alloc(cls, op))
1686 reg = arch_get_irn_register(op);
1687 rbitset_set(forbidden_regs, arch_register_get_index(reg));
1690 /* free registers of values last used at this instruction */
1691 free_last_uses(&live_nodes, node);
1693 /* assign output registers */
1694 /* TODO: 2 phases: first: pre-assigned ones, 2nd real regs */
1695 be_foreach_definition(node, cls, value,
1696 assign_reg(block, value, forbidden_regs);
1700 ir_nodeset_destroy(&live_nodes);
1703 block_info->processed = true;
1705 /* permute values at end of predecessor blocks in case of phi-nodes */
1708 for (p = 0; p < n_preds; ++p) {
1709 add_phi_permutations(block, p);
1713 /* if we have exactly 1 successor then we might be able to produce phi
1715 if (get_irn_n_edges_kind(block, EDGE_KIND_BLOCK) == 1) {
1716 const ir_edge_t *edge
1717 = get_irn_out_edge_first_kind(block, EDGE_KIND_BLOCK);
1718 ir_node *succ = get_edge_src_irn(edge);
1719 int p = get_edge_src_pos(edge);
1720 block_info_t *succ_info = get_block_info(succ);
1722 if (succ_info->processed) {
1723 add_phi_permutations(succ, p);
1728 typedef struct block_costs_t block_costs_t;
1729 struct block_costs_t {
1730 float costs; /**< costs of the block */
1731 int dfs_num; /**< depth first search number (to detect backedges) */
1734 static int cmp_block_costs(const void *d1, const void *d2)
1736 const ir_node * const *block1 = d1;
1737 const ir_node * const *block2 = d2;
1738 const block_costs_t *info1 = get_irn_link(*block1);
1739 const block_costs_t *info2 = get_irn_link(*block2);
1740 return QSORT_CMP(info2->costs, info1->costs);
1743 static void determine_block_order(void)
1746 ir_node **blocklist = be_get_cfgpostorder(irg);
1747 int n_blocks = ARR_LEN(blocklist);
1749 pdeq *worklist = new_pdeq();
1750 ir_node **order = XMALLOCN(ir_node*, n_blocks);
1753 /* clear block links... */
1754 for (i = 0; i < n_blocks; ++i) {
1755 ir_node *block = blocklist[i];
1756 set_irn_link(block, NULL);
1759 /* walk blocks in reverse postorder, the costs for each block are the
1760 * sum of the costs of its predecessors (excluding the costs on backedges
1761 * which we can't determine) */
1762 for (i = n_blocks-1; i >= 0; --i) {
1763 block_costs_t *cost_info;
1764 ir_node *block = blocklist[i];
1766 float execfreq = (float)get_block_execfreq(execfreqs, block);
1767 float costs = execfreq;
1768 int n_cfgpreds = get_Block_n_cfgpreds(block);
1770 for (p = 0; p < n_cfgpreds; ++p) {
1771 ir_node *pred_block = get_Block_cfgpred_block(block, p);
1772 block_costs_t *pred_costs = get_irn_link(pred_block);
1773 /* we don't have any info for backedges */
1774 if (pred_costs == NULL)
1776 costs += pred_costs->costs;
1779 cost_info = OALLOCZ(&obst, block_costs_t);
1780 cost_info->costs = costs;
1781 cost_info->dfs_num = dfs_num++;
1782 set_irn_link(block, cost_info);
1785 /* sort array by block costs */
1786 qsort(blocklist, n_blocks, sizeof(blocklist[0]), cmp_block_costs);
1788 ir_reserve_resources(irg, IR_RESOURCE_BLOCK_VISITED);
1789 inc_irg_block_visited(irg);
1791 for (i = 0; i < n_blocks; ++i) {
1792 ir_node *block = blocklist[i];
1793 if (Block_block_visited(block))
1796 /* continually add predecessors with highest costs to worklist
1797 * (without using backedges) */
1799 block_costs_t *info = get_irn_link(block);
1800 ir_node *best_pred = NULL;
1801 float best_costs = -1;
1802 int n_cfgpred = get_Block_n_cfgpreds(block);
1805 pdeq_putr(worklist, block);
1806 mark_Block_block_visited(block);
1807 for (i = 0; i < n_cfgpred; ++i) {
1808 ir_node *pred_block = get_Block_cfgpred_block(block, i);
1809 block_costs_t *pred_info = get_irn_link(pred_block);
1811 /* ignore backedges */
1812 if (pred_info->dfs_num > info->dfs_num)
1815 if (info->costs > best_costs) {
1816 best_costs = info->costs;
1817 best_pred = pred_block;
1821 } while (block != NULL && !Block_block_visited(block));
1823 /* now put all nodes in the worklist in our final order */
1824 while (!pdeq_empty(worklist)) {
1825 ir_node *pblock = pdeq_getr(worklist);
1826 assert(order_p < n_blocks);
1827 order[order_p++] = pblock;
1830 assert(order_p == n_blocks);
1833 ir_free_resources(irg, IR_RESOURCE_BLOCK_VISITED);
1835 DEL_ARR_F(blocklist);
1837 obstack_free(&obst, NULL);
1838 obstack_init(&obst);
1840 block_order = order;
1841 n_block_order = n_blocks;
1845 * Run the register allocator for the current register class.
1847 static void be_pref_alloc_cls(void)
1851 lv = be_assure_liveness(irg);
1852 be_liveness_assure_sets(lv);
1854 ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
1856 DB((dbg, LEVEL_2, "=== Allocating registers of %s ===\n", cls->name));
1858 be_clear_links(irg);
1860 irg_block_walk_graph(irg, NULL, analyze_block, NULL);
1861 if (create_congruence_classes)
1862 combine_congruence_classes();
1864 for (i = 0; i < n_block_order; ++i) {
1865 ir_node *block = block_order[i];
1866 allocate_coalesce_block(block, NULL);
1869 ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
1872 static void dump(int mask, ir_graph *irg, const char *suffix)
1874 if (be_get_irg_options(irg)->dump_flags & mask)
1875 dump_ir_graph(irg, suffix);
1879 * Run the spiller on the current graph.
1881 static void spill(void)
1883 /* make sure all nodes show their real register pressure */
1884 be_timer_push(T_RA_CONSTR);
1885 be_pre_spill_prepare_constr(irg, cls);
1886 be_timer_pop(T_RA_CONSTR);
1888 dump(DUMP_RA, irg, "-spillprepare");
1891 be_timer_push(T_RA_SPILL);
1892 be_do_spill(irg, cls);
1893 be_timer_pop(T_RA_SPILL);
1895 be_timer_push(T_RA_SPILL_APPLY);
1896 check_for_memory_operands(irg);
1897 be_timer_pop(T_RA_SPILL_APPLY);
1899 dump(DUMP_RA, irg, "-spill");
1903 * The pref register allocator for a whole procedure.
1905 static void be_pref_alloc(ir_graph *new_irg)
1907 const arch_env_t *arch_env = be_get_irg_arch_env(new_irg);
1908 int n_cls = arch_env_get_n_reg_class(arch_env);
1911 obstack_init(&obst);
1914 execfreqs = be_get_irg_exec_freq(irg);
1916 /* determine a good coloring order */
1917 determine_block_order();
1919 for (c = 0; c < n_cls; ++c) {
1920 cls = arch_env_get_reg_class(arch_env, c);
1921 default_cls_req = NULL;
1922 if (arch_register_class_flags(cls) & arch_register_class_flag_manual_ra)
1925 stat_ev_ctx_push_str("regcls", cls->name);
1927 n_regs = arch_register_class_n_regs(cls);
1928 normal_regs = rbitset_malloc(n_regs);
1929 be_abi_set_non_ignore_regs(be_get_irg_abi(irg), cls, normal_regs);
1933 /* verify schedule and register pressure */
1934 be_timer_push(T_VERIFY);
1935 if (be_get_irg_options(irg)->verify_option == BE_VERIFY_WARN) {
1936 be_verify_schedule(irg);
1937 be_verify_register_pressure(irg, cls);
1938 } else if (be_get_irg_options(irg)->verify_option == BE_VERIFY_ASSERT) {
1939 assert(be_verify_schedule(irg) && "Schedule verification failed");
1940 assert(be_verify_register_pressure(irg, cls)
1941 && "Register pressure verification failed");
1943 be_timer_pop(T_VERIFY);
1945 be_timer_push(T_RA_COLOR);
1946 be_pref_alloc_cls();
1947 be_timer_pop(T_RA_COLOR);
1949 /* we most probably constructed new Phis so liveness info is invalid
1951 /* TODO: test liveness_introduce */
1952 be_liveness_invalidate(lv);
1955 stat_ev_ctx_pop("regcls");
1958 be_timer_push(T_RA_SPILL_APPLY);
1959 be_abi_fix_stack_nodes(irg);
1960 be_timer_pop(T_RA_SPILL_APPLY);
1962 be_timer_push(T_VERIFY);
1963 if (be_get_irg_options(irg)->verify_option == BE_VERIFY_WARN) {
1964 be_verify_register_allocation(irg);
1965 } else if (be_get_irg_options(irg)->verify_option == BE_VERIFY_ASSERT) {
1966 assert(be_verify_register_allocation(irg)
1967 && "Register allocation invalid");
1969 be_timer_pop(T_VERIFY);
1971 obstack_free(&obst, NULL);
1974 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_pref_alloc);
1975 void be_init_pref_alloc(void)
1977 static be_ra_t be_ra_pref = {
1980 lc_opt_entry_t *be_grp = lc_opt_get_grp(firm_opt_get_root(), "be");
1981 lc_opt_entry_t *prefalloc_group = lc_opt_get_grp(be_grp, "prefalloc");
1982 lc_opt_add_table(prefalloc_group, options);
1984 be_register_allocator("pref", &be_ra_pref);
1985 FIRM_DBG_REGISTER(dbg, "firm.be.prefalloc");