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;
188 default_cls_req = req;
190 return default_cls_req;
194 * Link the allocation info of a node to a copy.
195 * Afterwards, both nodes uses the same allocation info.
196 * Copy must not have an allocation info assigned yet.
198 * @param copy the node that gets the allocation info assigned
199 * @param value the original node
201 static void mark_as_copy_of(ir_node *copy, ir_node *value)
204 allocation_info_t *info = get_allocation_info(value);
205 allocation_info_t *copy_info = get_allocation_info(copy);
207 /* find original value */
208 original = info->original_value;
209 if (original != value) {
210 info = get_allocation_info(original);
213 assert(info->original_value == original);
214 info->current_value = copy;
216 /* the copy should not be linked to something else yet */
217 assert(copy_info->original_value == copy);
218 copy_info->original_value = original;
220 /* copy over allocation preferences */
221 memcpy(copy_info->prefs, info->prefs, n_regs * sizeof(copy_info->prefs[0]));
225 * Calculate the penalties for every register on a node and its live neighbors.
227 * @param live_nodes the set of live nodes at the current position, may be NULL
228 * @param penalty the penalty to subtract from
229 * @param limited a raw bitset containing the limited set for the node
230 * @param node the node
232 static void give_penalties_for_limits(const ir_nodeset_t *live_nodes,
233 float penalty, const unsigned* limited,
236 ir_nodeset_iterator_t iter;
239 allocation_info_t *info = get_allocation_info(node);
242 /* give penalty for all forbidden regs */
243 for (r = 0; r < n_regs; ++r) {
244 if (rbitset_is_set(limited, r))
247 info->prefs[r] -= penalty;
250 /* all other live values should get a penalty for allowed regs */
251 if (live_nodes == NULL)
254 penalty *= NEIGHBOR_FACTOR;
255 n_allowed = rbitset_popcount(limited, n_regs);
257 /* only create a very weak penalty if multiple regs are allowed */
258 penalty = (penalty * 0.8f) / n_allowed;
260 foreach_ir_nodeset(live_nodes, neighbor, iter) {
261 allocation_info_t *neighbor_info;
263 /* TODO: if op is used on multiple inputs we might not do a
265 if (neighbor == node)
268 neighbor_info = get_allocation_info(neighbor);
269 for (r = 0; r < n_regs; ++r) {
270 if (!rbitset_is_set(limited, r))
273 neighbor_info->prefs[r] -= penalty;
279 * Calculate the preferences of a definition for the current register class.
280 * If the definition uses a limited set of registers, reduce the preferences
281 * for the limited register on the node and its neighbors.
283 * @param live_nodes the set of live nodes at the current node
284 * @param weight the weight
285 * @param node the current node
287 static void check_defs(const ir_nodeset_t *live_nodes, float weight,
290 const arch_register_req_t *req = arch_get_register_req_out(node);
291 if (req->type & arch_register_req_type_limited) {
292 const unsigned *limited = req->limited;
293 float penalty = weight * DEF_FACTOR;
294 give_penalties_for_limits(live_nodes, penalty, limited, node);
297 if (req->type & arch_register_req_type_should_be_same) {
298 ir_node *insn = skip_Proj(node);
299 allocation_info_t *info = get_allocation_info(node);
300 int arity = get_irn_arity(insn);
303 float factor = 1.0f / rbitset_popcount(&req->other_same, arity);
304 for (i = 0; i < arity; ++i) {
307 allocation_info_t *op_info;
309 if (!rbitset_is_set(&req->other_same, i))
312 op = get_irn_n(insn, i);
314 /* if we the value at the should_be_same input doesn't die at the
315 * node, then it is no use to propagate the constraints (since a
316 * copy will emerge anyway) */
317 if (ir_nodeset_contains(live_nodes, op))
320 op_info = get_allocation_info(op);
321 for (r = 0; r < n_regs; ++r) {
322 op_info->prefs[r] += info->prefs[r] * factor;
329 * Walker: Runs an a block calculates the preferences for any
330 * node and every register from the considered register class.
332 static void analyze_block(ir_node *block, void *data)
334 float weight = (float)get_block_execfreq(execfreqs, block);
335 ir_nodeset_t live_nodes;
339 ir_nodeset_init(&live_nodes);
340 be_liveness_end_of_block(lv, cls, block, &live_nodes);
342 sched_foreach_reverse(block, node) {
343 allocation_info_t *info;
350 if (create_preferences) {
352 be_foreach_definition(node, cls, value,
353 check_defs(&live_nodes, weight, value);
358 arity = get_irn_arity(node);
360 /* the allocation info node currently only uses 1 unsigned value
361 to mark last used inputs. So we will fail for a node with more than
363 if (arity >= (int) sizeof(info->last_uses) * 8) {
364 panic("Node with more than %d inputs not supported yet",
365 (int) sizeof(info->last_uses) * 8);
368 info = get_allocation_info(node);
369 for (i = 0; i < arity; ++i) {
370 ir_node *op = get_irn_n(node, i);
371 if (!arch_irn_consider_in_reg_alloc(cls, op))
374 /* last usage of a value? */
375 if (!ir_nodeset_contains(&live_nodes, op)) {
376 rbitset_set(info->last_uses, i);
380 be_liveness_transfer(cls, node, &live_nodes);
382 if (create_preferences) {
383 /* update weights based on usage constraints */
384 for (i = 0; i < arity; ++i) {
385 const arch_register_req_t *req;
386 const unsigned *limited;
387 ir_node *op = get_irn_n(node, i);
389 if (!arch_irn_consider_in_reg_alloc(cls, op))
392 req = arch_get_register_req(node, i);
393 if (!(req->type & arch_register_req_type_limited))
396 limited = req->limited;
397 give_penalties_for_limits(&live_nodes, weight * USE_FACTOR,
403 ir_nodeset_destroy(&live_nodes);
406 static void congruence_def(ir_nodeset_t *live_nodes, const ir_node *node)
408 const arch_register_req_t *req = arch_get_register_req_out(node);
410 /* should be same constraint? */
411 if (req->type & arch_register_req_type_should_be_same) {
412 const ir_node *insn = skip_Proj_const(node);
413 int arity = get_irn_arity(insn);
415 unsigned node_idx = get_irn_idx(node);
416 node_idx = uf_find(congruence_classes, node_idx);
418 for (i = 0; i < arity; ++i) {
422 ir_nodeset_iterator_t iter;
423 bool interferes = false;
425 if (!rbitset_is_set(&req->other_same, i))
428 op = get_irn_n(insn, i);
429 op_idx = get_irn_idx(op);
430 op_idx = uf_find(congruence_classes, op_idx);
432 /* do we interfere with the value */
433 foreach_ir_nodeset(live_nodes, live, iter) {
434 int lv_idx = get_irn_idx(live);
435 lv_idx = uf_find(congruence_classes, lv_idx);
436 if (lv_idx == op_idx) {
441 /* don't put in same affinity class if we interfere */
445 node_idx = uf_union(congruence_classes, node_idx, op_idx);
446 DB((dbg, LEVEL_3, "Merge %+F and %+F congruence classes\n",
448 /* one should_be_same is enough... */
454 static void create_congruence_class(ir_node *block, void *data)
456 ir_nodeset_t live_nodes;
460 ir_nodeset_init(&live_nodes);
461 be_liveness_end_of_block(lv, cls, block, &live_nodes);
463 /* check should be same constraints */
464 sched_foreach_reverse(block, node) {
469 be_foreach_definition(node, cls, value,
470 congruence_def(&live_nodes, value);
472 be_liveness_transfer(cls, node, &live_nodes);
475 /* check phi congruence classes */
476 sched_foreach_reverse_from(node, node) {
480 assert(is_Phi(node));
482 if (!arch_irn_consider_in_reg_alloc(cls, node))
485 node_idx = get_irn_idx(node);
486 node_idx = uf_find(congruence_classes, node_idx);
488 arity = get_irn_arity(node);
489 for (i = 0; i < arity; ++i) {
490 bool interferes = false;
491 ir_nodeset_iterator_t iter;
496 allocation_info_t *head_info;
497 allocation_info_t *other_info;
498 ir_node *op = get_Phi_pred(node, i);
499 int op_idx = get_irn_idx(op);
500 op_idx = uf_find(congruence_classes, op_idx);
502 /* do we interfere with the value */
503 foreach_ir_nodeset(&live_nodes, live, iter) {
504 int lv_idx = get_irn_idx(live);
505 lv_idx = uf_find(congruence_classes, lv_idx);
506 if (lv_idx == op_idx) {
511 /* don't put in same affinity class if we interfere */
514 /* any other phi has the same input? */
515 sched_foreach(block, phi) {
520 if (!arch_irn_consider_in_reg_alloc(cls, phi))
522 oop = get_Phi_pred(phi, i);
525 oop_idx = get_irn_idx(oop);
526 oop_idx = uf_find(congruence_classes, oop_idx);
527 if (oop_idx == op_idx) {
535 /* merge the 2 congruence classes and sum up their preferences */
536 old_node_idx = node_idx;
537 node_idx = uf_union(congruence_classes, node_idx, op_idx);
538 DB((dbg, LEVEL_3, "Merge %+F and %+F congruence classes\n",
541 old_node_idx = node_idx == old_node_idx ? op_idx : old_node_idx;
542 head_info = get_allocation_info(get_idx_irn(irg, node_idx));
543 other_info = get_allocation_info(get_idx_irn(irg, old_node_idx));
544 for (r = 0; r < n_regs; ++r) {
545 head_info->prefs[r] += other_info->prefs[r];
551 static void set_congruence_prefs(ir_node *node, void *data)
553 allocation_info_t *info;
554 allocation_info_t *head_info;
555 unsigned node_idx = get_irn_idx(node);
556 unsigned node_set = uf_find(congruence_classes, node_idx);
560 /* head of congruence class or not in any class */
561 if (node_set == node_idx)
564 if (!arch_irn_consider_in_reg_alloc(cls, node))
567 head_info = get_allocation_info(get_idx_irn(irg, node_set));
568 info = get_allocation_info(node);
570 memcpy(info->prefs, head_info->prefs, n_regs * sizeof(info->prefs[0]));
573 static void combine_congruence_classes(void)
575 size_t n = get_irg_last_idx(irg);
576 congruence_classes = XMALLOCN(int, n);
577 uf_init(congruence_classes, n);
579 /* create congruence classes */
580 irg_block_walk_graph(irg, create_congruence_class, NULL, NULL);
581 /* merge preferences */
582 irg_walk_graph(irg, set_congruence_prefs, NULL, NULL);
583 free(congruence_classes);
589 * Assign register reg to the given node.
591 * @param node the node
592 * @param reg the register
594 static void use_reg(ir_node *node, const arch_register_t *reg)
596 unsigned r = arch_register_get_index(reg);
597 assignments[r] = node;
598 arch_set_irn_register(node, reg);
601 static void free_reg_of_value(ir_node *node)
603 const arch_register_t *reg;
606 if (!arch_irn_consider_in_reg_alloc(cls, node))
609 reg = arch_get_irn_register(node);
610 r = arch_register_get_index(reg);
611 /* assignment->value may be NULL if a value is used at 2 inputs
612 so it gets freed twice. */
613 assert(assignments[r] == node || assignments[r] == NULL);
614 assignments[r] = NULL;
618 * Compare two register preferences in decreasing order.
620 static int compare_reg_pref(const void *e1, const void *e2)
622 const reg_pref_t *rp1 = (const reg_pref_t*) e1;
623 const reg_pref_t *rp2 = (const reg_pref_t*) e2;
624 if (rp1->pref < rp2->pref)
626 if (rp1->pref > rp2->pref)
631 static void fill_sort_candidates(reg_pref_t *regprefs,
632 const allocation_info_t *info)
636 for (r = 0; r < n_regs; ++r) {
637 float pref = info->prefs[r];
639 regprefs[r].pref = pref;
641 /* TODO: use a stable sort here to avoid unnecessary register jumping */
642 qsort(regprefs, n_regs, sizeof(regprefs[0]), compare_reg_pref);
645 static bool try_optimistic_split(ir_node *to_split, ir_node *before,
646 float pref, float pref_delta,
647 unsigned *forbidden_regs, int recursion)
649 const arch_register_t *from_reg;
650 const arch_register_t *reg;
651 ir_node *original_insn;
657 allocation_info_t *info = get_allocation_info(to_split);
660 float split_threshold;
664 /* stupid hack: don't optimisticallt split don't spill nodes...
665 * (so we don't split away the values produced because of
666 * must_be_different constraints) */
667 original_insn = skip_Proj(info->original_value);
668 if (arch_irn_get_flags(original_insn) & arch_irn_flags_dont_spill)
671 from_reg = arch_get_irn_register(to_split);
672 from_r = arch_register_get_index(from_reg);
673 block = get_nodes_block(before);
674 split_threshold = (float)get_block_execfreq(execfreqs, block) * SPLIT_DELTA;
676 if (pref_delta < split_threshold*0.5)
679 /* find the best free position where we could move to */
680 prefs = ALLOCAN(reg_pref_t, n_regs);
681 fill_sort_candidates(prefs, info);
682 for (i = 0; i < n_regs; ++i) {
686 bool old_source_state;
688 /* we need a normal register which is not an output register
689 an different from the current register of to_split */
691 if (!rbitset_is_set(normal_regs, r))
693 if (rbitset_is_set(forbidden_regs, r))
698 /* is the split worth it? */
699 delta = pref_delta + prefs[i].pref;
700 if (delta < split_threshold) {
701 DB((dbg, LEVEL_3, "Not doing optimistical split of %+F (depth %d), win %f too low\n",
702 to_split, recursion, delta));
706 /* if the register is free then we can do the split */
707 if (assignments[r] == NULL)
710 /* otherwise we might try recursively calling optimistic_split */
711 if (recursion+1 > MAX_OPTIMISTIC_SPLIT_RECURSION)
714 apref = prefs[i].pref;
715 apref_delta = i+1 < n_regs ? apref - prefs[i+1].pref : 0;
716 apref_delta += pref_delta - split_threshold;
718 /* our source register isn't a useful destination for recursive
720 old_source_state = rbitset_is_set(forbidden_regs, from_r);
721 rbitset_set(forbidden_regs, from_r);
722 /* try recursive split */
723 res = try_optimistic_split(assignments[r], before, apref,
724 apref_delta, forbidden_regs, recursion+1);
725 /* restore our destination */
726 if (old_source_state) {
727 rbitset_set(forbidden_regs, from_r);
729 rbitset_clear(forbidden_regs, from_r);
738 reg = arch_register_for_index(cls, r);
739 copy = be_new_Copy(cls, block, to_split);
740 mark_as_copy_of(copy, to_split);
741 /* hacky, but correct here */
742 if (assignments[arch_register_get_index(from_reg)] == to_split)
743 free_reg_of_value(to_split);
745 sched_add_before(before, copy);
748 "Optimistic live-range split %+F move %+F(%s) -> %s before %+F (win %f, depth %d)\n",
749 copy, to_split, from_reg->name, reg->name, before, delta, recursion));
754 * Determine and assign a register for node @p node
756 static void assign_reg(const ir_node *block, ir_node *node,
757 unsigned *forbidden_regs)
759 const arch_register_t *reg;
760 allocation_info_t *info;
761 const arch_register_req_t *req;
762 reg_pref_t *reg_prefs;
765 const unsigned *allowed_regs;
768 assert(!is_Phi(node));
769 assert(arch_irn_consider_in_reg_alloc(cls, node));
771 /* preassigned register? */
772 reg = arch_get_irn_register(node);
774 DB((dbg, LEVEL_2, "Preassignment %+F -> %s\n", node, reg->name));
779 /* give should_be_same boni */
780 info = get_allocation_info(node);
781 req = arch_get_register_req_out(node);
783 in_node = skip_Proj(node);
784 if (req->type & arch_register_req_type_should_be_same) {
785 float weight = (float)get_block_execfreq(execfreqs, block);
786 int arity = get_irn_arity(in_node);
789 assert(arity <= (int) sizeof(req->other_same) * 8);
790 for (i = 0; i < arity; ++i) {
792 const arch_register_t *reg;
794 if (!rbitset_is_set(&req->other_same, i))
797 in = get_irn_n(in_node, i);
798 reg = arch_get_irn_register(in);
800 r = arch_register_get_index(reg);
802 /* if the value didn't die here then we should not propagate the
803 * should_be_same info */
804 if (assignments[r] == in)
807 info->prefs[r] += weight * AFF_SHOULD_BE_SAME;
811 /* create list of register candidates and sort by their preference */
812 DB((dbg, LEVEL_2, "Candidates for %+F:", node));
813 reg_prefs = alloca(n_regs * sizeof(reg_prefs[0]));
814 fill_sort_candidates(reg_prefs, info);
815 for (i = 0; i < n_regs; ++i) {
816 unsigned num = reg_prefs[i].num;
817 const arch_register_t *reg;
819 if (!rbitset_is_set(normal_regs, num))
822 reg = arch_register_for_index(cls, num);
823 DB((dbg, LEVEL_2, " %s(%f)", reg->name, reg_prefs[i].pref));
825 DB((dbg, LEVEL_2, "\n"));
827 allowed_regs = normal_regs;
828 if (req->type & arch_register_req_type_limited) {
829 allowed_regs = req->limited;
832 for (i = 0; i < n_regs; ++i) {
837 r = reg_prefs[i].num;
838 if (!rbitset_is_set(allowed_regs, r))
840 if (assignments[r] == NULL)
842 pref = reg_prefs[i].pref;
843 delta = i+1 < n_regs ? pref - reg_prefs[i+1].pref : 0;
844 before = skip_Proj(node);
845 res = try_optimistic_split(assignments[r], before,
846 pref, delta, forbidden_regs, 0);
851 /* the common reason to hit this panic is when 1 of your nodes is not
852 * register pressure faithful */
853 panic("No register left for %+F\n", node);
856 reg = arch_register_for_index(cls, r);
857 DB((dbg, LEVEL_2, "Assign %+F -> %s\n", node, reg->name));
862 * Add an permutation in front of a node and change the assignments
863 * due to this permutation.
865 * To understand this imagine a permutation like this:
875 * First we count how many destinations a single value has. At the same time
876 * we can be sure that each destination register has at most 1 source register
877 * (it can have 0 which means we don't care what value is in it).
878 * We ignore all fullfilled permuations (like 7->7)
879 * In a first pass we create as much copy instructions as possible as they
880 * are generally cheaper than exchanges. We do this by counting into how many
881 * destinations a register has to be copied (in the example it's 2 for register
882 * 3, or 1 for the registers 1,2,4 and 7).
883 * We can then create a copy into every destination register when the usecount
884 * of that register is 0 (= noone else needs the value in the register).
886 * After this step we should have cycles left. We implement a cyclic permutation
887 * of n registers with n-1 transpositions.
889 * @param live_nodes the set of live nodes, updated due to live range split
890 * @param before the node before we add the permutation
891 * @param permutation the permutation array indices are the destination
892 * registers, the values in the array are the source
895 static void permute_values(ir_nodeset_t *live_nodes, ir_node *before,
896 unsigned *permutation)
898 unsigned *n_used = ALLOCANZ(unsigned, n_regs);
902 /* determine how often each source register needs to be read */
903 for (r = 0; r < n_regs; ++r) {
904 unsigned old_reg = permutation[r];
907 value = assignments[old_reg];
909 /* nothing to do here, reg is not live. Mark it as fixpoint
910 * so we ignore it in the next steps */
918 block = get_nodes_block(before);
920 /* step1: create copies where immediately possible */
921 for (r = 0; r < n_regs; /* empty */) {
924 const arch_register_t *reg;
925 unsigned old_r = permutation[r];
927 /* - no need to do anything for fixed points.
928 - we can't copy if the value in the dest reg is still needed */
929 if (old_r == r || n_used[r] > 0) {
935 src = assignments[old_r];
936 copy = be_new_Copy(cls, block, src);
937 sched_add_before(before, copy);
938 reg = arch_register_for_index(cls, r);
939 DB((dbg, LEVEL_2, "Copy %+F (from %+F, before %+F) -> %s\n",
940 copy, src, before, reg->name));
941 mark_as_copy_of(copy, src);
944 if (live_nodes != NULL) {
945 ir_nodeset_insert(live_nodes, copy);
948 /* old register has 1 user less, permutation is resolved */
949 assert(arch_register_get_index(arch_get_irn_register(src)) == old_r);
952 assert(n_used[old_r] > 0);
954 if (n_used[old_r] == 0) {
955 if (live_nodes != NULL) {
956 ir_nodeset_remove(live_nodes, src);
958 free_reg_of_value(src);
961 /* advance or jump back (if this copy enabled another copy) */
962 if (old_r < r && n_used[old_r] == 0) {
969 /* at this point we only have "cycles" left which we have to resolve with
971 * TODO: if we have free registers left, then we should really use copy
972 * instructions for any cycle longer than 2 registers...
973 * (this is probably architecture dependent, there might be archs where
974 * copies are preferable even for 2-cycles) */
976 /* create perms with the rest */
977 for (r = 0; r < n_regs; /* empty */) {
978 const arch_register_t *reg;
979 unsigned old_r = permutation[r];
991 /* we shouldn't have copies from 1 value to multiple destinations left*/
992 assert(n_used[old_r] == 1);
994 /* exchange old_r and r2; after that old_r is a fixed point */
995 r2 = permutation[old_r];
997 in[0] = assignments[r2];
998 in[1] = assignments[old_r];
999 perm = be_new_Perm(cls, block, 2, in);
1000 sched_add_before(before, perm);
1001 DB((dbg, LEVEL_2, "Perm %+F (perm %+F,%+F, before %+F)\n",
1002 perm, in[0], in[1], before));
1004 proj0 = new_r_Proj(perm, get_irn_mode(in[0]), 0);
1005 mark_as_copy_of(proj0, in[0]);
1006 reg = arch_register_for_index(cls, old_r);
1007 use_reg(proj0, reg);
1009 proj1 = new_r_Proj(perm, get_irn_mode(in[1]), 1);
1010 mark_as_copy_of(proj1, in[1]);
1011 reg = arch_register_for_index(cls, r2);
1012 use_reg(proj1, reg);
1014 /* 1 value is now in the correct register */
1015 permutation[old_r] = old_r;
1016 /* the source of r changed to r2 */
1017 permutation[r] = r2;
1019 /* if we have reached a fixpoint update data structures */
1020 if (live_nodes != NULL) {
1021 ir_nodeset_remove(live_nodes, in[0]);
1022 ir_nodeset_remove(live_nodes, in[1]);
1023 ir_nodeset_remove(live_nodes, proj0);
1024 ir_nodeset_insert(live_nodes, proj1);
1028 #ifdef DEBUG_libfirm
1029 /* now we should only have fixpoints left */
1030 for (r = 0; r < n_regs; ++r) {
1031 assert(permutation[r] == r);
1037 * Free regs for values last used.
1039 * @param live_nodes set of live nodes, will be updated
1040 * @param node the node to consider
1042 static void free_last_uses(ir_nodeset_t *live_nodes, ir_node *node)
1044 allocation_info_t *info = get_allocation_info(node);
1045 const unsigned *last_uses = info->last_uses;
1046 int arity = get_irn_arity(node);
1049 for (i = 0; i < arity; ++i) {
1052 /* check if one operand is the last use */
1053 if (!rbitset_is_set(last_uses, i))
1056 op = get_irn_n(node, i);
1057 free_reg_of_value(op);
1058 ir_nodeset_remove(live_nodes, op);
1063 * change inputs of a node to the current value (copies/perms)
1065 static void rewire_inputs(ir_node *node)
1068 int arity = get_irn_arity(node);
1070 for (i = 0; i < arity; ++i) {
1071 ir_node *op = get_irn_n(node, i);
1072 allocation_info_t *info = try_get_allocation_info(op);
1077 info = get_allocation_info(info->original_value);
1078 if (info->current_value != op) {
1079 set_irn_n(node, i, info->current_value);
1085 * Create a bitset of registers occupied with value living through an
1088 static void determine_live_through_regs(unsigned *bitset, ir_node *node)
1090 const allocation_info_t *info = get_allocation_info(node);
1095 /* mark all used registers as potentially live-through */
1096 for (r = 0; r < n_regs; ++r) {
1097 if (assignments[r] == NULL)
1099 if (!rbitset_is_set(normal_regs, r))
1102 rbitset_set(bitset, r);
1105 /* remove registers of value dying at the instruction */
1106 arity = get_irn_arity(node);
1107 for (i = 0; i < arity; ++i) {
1109 const arch_register_t *reg;
1111 if (!rbitset_is_set(info->last_uses, i))
1114 op = get_irn_n(node, i);
1115 reg = arch_get_irn_register(op);
1116 rbitset_clear(bitset, arch_register_get_index(reg));
1121 * Enforce constraints at a node by live range splits.
1123 * @param live_nodes the set of live nodes, might be changed
1124 * @param node the current node
1126 static void enforce_constraints(ir_nodeset_t *live_nodes, ir_node *node,
1127 unsigned *forbidden_regs)
1129 int arity = get_irn_arity(node);
1131 hungarian_problem_t *bp;
1133 unsigned *assignment;
1136 /* construct a list of register occupied by live-through values */
1137 unsigned *live_through_regs = NULL;
1139 /* see if any use constraints are not met */
1141 for (i = 0; i < arity; ++i) {
1142 ir_node *op = get_irn_n(node, i);
1143 const arch_register_t *reg;
1144 const arch_register_req_t *req;
1145 const unsigned *limited;
1148 if (!arch_irn_consider_in_reg_alloc(cls, op))
1151 /* are there any limitations for the i'th operand? */
1152 req = arch_get_register_req(node, i);
1153 if (!(req->type & arch_register_req_type_limited))
1156 limited = req->limited;
1157 reg = arch_get_irn_register(op);
1158 r = arch_register_get_index(reg);
1159 if (!rbitset_is_set(limited, r)) {
1160 /* found an assignment outside the limited set */
1166 /* is any of the live-throughs using a constrained output register? */
1167 be_foreach_definition(node, cls, value,
1168 if (! (req_->type & arch_register_req_type_limited))
1170 if (live_through_regs == NULL) {
1171 rbitset_alloca(live_through_regs, n_regs);
1172 determine_live_through_regs(live_through_regs, node);
1174 rbitset_or(forbidden_regs, req_->limited, n_regs);
1175 if (rbitsets_have_common(req_->limited, live_through_regs, n_regs))
1182 /* create these arrays if we haven't yet */
1183 if (live_through_regs == NULL) {
1184 rbitset_alloca(live_through_regs, n_regs);
1187 /* at this point we have to construct a bipartite matching problem to see
1188 * which values should go to which registers
1189 * Note: We're building the matrix in "reverse" - source registers are
1190 * right, destinations left because this will produce the solution
1191 * in the format required for permute_values.
1193 bp = hungarian_new(n_regs, n_regs, HUNGARIAN_MATCH_PERFECT);
1195 /* add all combinations, then remove not allowed ones */
1196 for (l = 0; l < n_regs; ++l) {
1197 if (!rbitset_is_set(normal_regs, l)) {
1198 hungarian_add(bp, l, l, 1);
1202 for (r = 0; r < n_regs; ++r) {
1203 if (!rbitset_is_set(normal_regs, r))
1205 /* livethrough values may not use constrainted output registers */
1206 if (rbitset_is_set(live_through_regs, l)
1207 && rbitset_is_set(forbidden_regs, r))
1210 hungarian_add(bp, r, l, l == r ? 9 : 8);
1214 for (i = 0; i < arity; ++i) {
1215 ir_node *op = get_irn_n(node, i);
1216 const arch_register_t *reg;
1217 const arch_register_req_t *req;
1218 const unsigned *limited;
1219 unsigned current_reg;
1221 if (!arch_irn_consider_in_reg_alloc(cls, op))
1224 req = arch_get_register_req(node, i);
1225 if (!(req->type & arch_register_req_type_limited))
1228 limited = req->limited;
1229 reg = arch_get_irn_register(op);
1230 current_reg = arch_register_get_index(reg);
1231 for (r = 0; r < n_regs; ++r) {
1232 if (rbitset_is_set(limited, r))
1234 hungarian_remove(bp, r, current_reg);
1238 //hungarian_print_cost_matrix(bp, 1);
1239 hungarian_prepare_cost_matrix(bp, HUNGARIAN_MODE_MAXIMIZE_UTIL);
1241 assignment = ALLOCAN(unsigned, n_regs);
1242 res = hungarian_solve(bp, assignment, NULL, 0);
1246 fprintf(stderr, "Swap result:");
1247 for (i = 0; i < (int) n_regs; ++i) {
1248 fprintf(stderr, " %d", assignment[i]);
1250 fprintf(stderr, "\n");
1255 permute_values(live_nodes, node, assignment);
1258 /** test wether a node @p n is a copy of the value of node @p of */
1259 static bool is_copy_of(ir_node *value, ir_node *test_value)
1261 allocation_info_t *test_info;
1262 allocation_info_t *info;
1264 if (value == test_value)
1267 info = get_allocation_info(value);
1268 test_info = get_allocation_info(test_value);
1269 return test_info->original_value == info->original_value;
1273 * find a value in the end-assignment of a basic block
1274 * @returns the index into the assignment array if found
1277 static int find_value_in_block_info(block_info_t *info, ir_node *value)
1280 ir_node **assignments = info->assignments;
1281 for (r = 0; r < n_regs; ++r) {
1282 ir_node *a_value = assignments[r];
1284 if (a_value == NULL)
1286 if (is_copy_of(a_value, value))
1294 * Create the necessary permutations at the end of a basic block to fullfill
1295 * the register assignment for phi-nodes in the next block
1297 static void add_phi_permutations(ir_node *block, int p)
1300 unsigned *permutation;
1301 ir_node **old_assignments;
1302 bool need_permutation;
1304 ir_node *pred = get_Block_cfgpred_block(block, p);
1306 block_info_t *pred_info = get_block_info(pred);
1308 /* predecessor not processed yet? nothing to do */
1309 if (!pred_info->processed)
1312 permutation = ALLOCAN(unsigned, n_regs);
1313 for (r = 0; r < n_regs; ++r) {
1317 /* check phi nodes */
1318 need_permutation = false;
1319 node = sched_first(block);
1320 for ( ; is_Phi(node); node = sched_next(node)) {
1321 const arch_register_t *reg;
1326 if (!arch_irn_consider_in_reg_alloc(cls, node))
1329 op = get_Phi_pred(node, p);
1330 if (!arch_irn_consider_in_reg_alloc(cls, op))
1333 a = find_value_in_block_info(pred_info, op);
1336 reg = arch_get_irn_register(node);
1337 regn = arch_register_get_index(reg);
1339 permutation[regn] = a;
1340 need_permutation = true;
1344 if (need_permutation) {
1345 /* permute values at end of predecessor */
1346 old_assignments = assignments;
1347 assignments = pred_info->assignments;
1348 permute_values(NULL, be_get_end_of_block_insertion_point(pred),
1350 assignments = old_assignments;
1353 /* change phi nodes to use the copied values */
1354 node = sched_first(block);
1355 for ( ; is_Phi(node); node = sched_next(node)) {
1359 if (!arch_irn_consider_in_reg_alloc(cls, node))
1362 op = get_Phi_pred(node, p);
1363 /* no need to do anything for Unknown inputs */
1364 if (!arch_irn_consider_in_reg_alloc(cls, op))
1367 /* we have permuted all values into the correct registers so we can
1368 simply query which value occupies the phis register in the
1370 a = arch_register_get_index(arch_get_irn_register(node));
1371 op = pred_info->assignments[a];
1372 set_Phi_pred(node, p, op);
1377 * Set preferences for a phis register based on the registers used on the
1380 static void adapt_phi_prefs(ir_node *phi)
1383 int arity = get_irn_arity(phi);
1384 ir_node *block = get_nodes_block(phi);
1385 allocation_info_t *info = get_allocation_info(phi);
1387 for (i = 0; i < arity; ++i) {
1388 ir_node *op = get_irn_n(phi, i);
1389 const arch_register_t *reg = arch_get_irn_register(op);
1390 ir_node *pred_block;
1391 block_info_t *pred_block_info;
1397 /* we only give the bonus if the predecessor already has registers
1398 * assigned, otherwise we only see a dummy value
1399 * and any conclusions about its register are useless */
1400 pred_block = get_Block_cfgpred_block(block, i);
1401 pred_block_info = get_block_info(pred_block);
1402 if (!pred_block_info->processed)
1405 /* give bonus for already assigned register */
1406 weight = (float)get_block_execfreq(execfreqs, pred_block);
1407 r = arch_register_get_index(reg);
1408 info->prefs[r] += weight * AFF_PHI;
1413 * After a phi has been assigned a register propagate preference inputs
1414 * to the phi inputs.
1416 static void propagate_phi_register(ir_node *phi, unsigned assigned_r)
1419 ir_node *block = get_nodes_block(phi);
1420 int arity = get_irn_arity(phi);
1422 for (i = 0; i < arity; ++i) {
1423 ir_node *op = get_Phi_pred(phi, i);
1424 allocation_info_t *info = get_allocation_info(op);
1425 ir_node *pred_block = get_Block_cfgpred_block(block, i);
1428 = (float)get_block_execfreq(execfreqs, pred_block) * AFF_PHI;
1430 if (info->prefs[assigned_r] >= weight)
1433 /* promote the prefered register */
1434 for (r = 0; r < n_regs; ++r) {
1435 if (info->prefs[r] > -weight) {
1436 info->prefs[r] = -weight;
1439 info->prefs[assigned_r] = weight;
1442 propagate_phi_register(op, assigned_r);
1446 static void assign_phi_registers(ir_node *block)
1451 unsigned *assignment;
1453 hungarian_problem_t *bp;
1455 /* count phi nodes */
1456 sched_foreach(block, node) {
1459 if (!arch_irn_consider_in_reg_alloc(cls, node))
1467 /* build a bipartite matching problem for all phi nodes */
1468 bp = hungarian_new(n_phis, n_regs, HUNGARIAN_MATCH_PERFECT);
1470 sched_foreach(block, node) {
1473 allocation_info_t *info;
1476 if (!arch_irn_consider_in_reg_alloc(cls, node))
1479 /* give boni for predecessor colorings */
1480 adapt_phi_prefs(node);
1481 /* add stuff to bipartite problem */
1482 info = get_allocation_info(node);
1483 DB((dbg, LEVEL_3, "Prefs for %+F: ", node));
1484 for (r = 0; r < n_regs; ++r) {
1487 if (!rbitset_is_set(normal_regs, r))
1490 costs = info->prefs[r];
1491 costs = costs < 0 ? -logf(-costs+1) : logf(costs+1);
1494 hungarian_add(bp, n, r, (int)costs);
1495 DB((dbg, LEVEL_3, " %s(%f)", arch_register_for_index(cls, r)->name,
1498 DB((dbg, LEVEL_3, "\n"));
1502 //hungarian_print_cost_matrix(bp, 7);
1503 hungarian_prepare_cost_matrix(bp, HUNGARIAN_MODE_MAXIMIZE_UTIL);
1505 assignment = ALLOCAN(unsigned, n_regs);
1506 res = hungarian_solve(bp, assignment, NULL, 0);
1511 sched_foreach(block, node) {
1513 const arch_register_t *reg;
1517 if (!arch_irn_consider_in_reg_alloc(cls, node))
1520 r = assignment[n++];
1521 assert(rbitset_is_set(normal_regs, r));
1522 reg = arch_register_for_index(cls, r);
1523 DB((dbg, LEVEL_2, "Assign %+F -> %s\n", node, reg->name));
1526 /* adapt preferences for phi inputs */
1527 if (propagate_phi_registers)
1528 propagate_phi_register(node, r);
1533 * Walker: assign registers to all nodes of a block that
1534 * need registers from the currently considered register class.
1536 static void allocate_coalesce_block(ir_node *block, void *data)
1539 ir_nodeset_t live_nodes;
1542 block_info_t *block_info;
1543 block_info_t **pred_block_infos;
1545 unsigned *forbidden_regs; /**< collects registers which must
1546 not be used for optimistic splits */
1549 DB((dbg, LEVEL_2, "* Block %+F\n", block));
1551 /* clear assignments */
1552 block_info = get_block_info(block);
1553 assignments = block_info->assignments;
1555 ir_nodeset_init(&live_nodes);
1557 /* gather regalloc infos of predecessor blocks */
1558 n_preds = get_Block_n_cfgpreds(block);
1559 pred_block_infos = ALLOCAN(block_info_t*, n_preds);
1560 for (i = 0; i < n_preds; ++i) {
1561 ir_node *pred = get_Block_cfgpred_block(block, i);
1562 block_info_t *pred_info = get_block_info(pred);
1563 pred_block_infos[i] = pred_info;
1566 phi_ins = ALLOCAN(ir_node*, n_preds);
1568 /* collect live-in nodes and preassigned values */
1569 be_lv_foreach(lv, block, be_lv_state_in, i) {
1570 const arch_register_t *reg;
1572 bool need_phi = false;
1574 node = be_lv_get_irn(lv, block, i);
1575 if (!arch_irn_consider_in_reg_alloc(cls, node))
1578 /* check all predecessors for this value, if it is not everywhere the
1579 same or unknown then we have to construct a phi
1580 (we collect the potential phi inputs here) */
1581 for (p = 0; p < n_preds; ++p) {
1582 block_info_t *pred_info = pred_block_infos[p];
1584 if (!pred_info->processed) {
1585 /* use node for now, it will get fixed later */
1589 int a = find_value_in_block_info(pred_info, node);
1591 /* must live out of predecessor */
1593 phi_ins[p] = pred_info->assignments[a];
1594 /* different value from last time? then we need a phi */
1595 if (p > 0 && phi_ins[p-1] != phi_ins[p]) {
1602 ir_mode *mode = get_irn_mode(node);
1603 const arch_register_req_t *req = get_default_req_current_cls();
1606 phi = new_r_Phi(block, n_preds, phi_ins, mode);
1607 be_set_phi_reg_req(phi, req);
1609 DB((dbg, LEVEL_3, "Create Phi %+F (for %+F) -", phi, node));
1610 #ifdef DEBUG_libfirm
1613 for (i = 0; i < n_preds; ++i) {
1614 DB((dbg, LEVEL_3, " %+F", phi_ins[i]));
1616 DB((dbg, LEVEL_3, "\n"));
1619 mark_as_copy_of(phi, node);
1620 sched_add_after(block, phi);
1624 allocation_info_t *info = get_allocation_info(node);
1625 info->current_value = phi_ins[0];
1627 /* Grab 1 of the inputs we constructed (might not be the same as
1628 * "node" as we could see the same copy of the value in all
1633 /* if the node already has a register assigned use it */
1634 reg = arch_get_irn_register(node);
1639 /* remember that this node is live at the beginning of the block */
1640 ir_nodeset_insert(&live_nodes, node);
1643 rbitset_alloca(forbidden_regs, n_regs);
1645 /* handle phis... */
1646 assign_phi_registers(block);
1648 /* all live-ins must have a register */
1649 #ifdef DEBUG_libfirm
1651 ir_nodeset_iterator_t iter;
1652 foreach_ir_nodeset(&live_nodes, node, iter) {
1653 const arch_register_t *reg = arch_get_irn_register(node);
1654 assert(reg != NULL);
1659 /* assign instructions in the block */
1660 sched_foreach(block, node) {
1665 /* phis are already assigned */
1669 rewire_inputs(node);
1671 /* enforce use constraints */
1672 rbitset_clear_all(forbidden_regs, n_regs);
1673 enforce_constraints(&live_nodes, node, forbidden_regs);
1675 rewire_inputs(node);
1677 /* we may not use registers used for inputs for optimistic splits */
1678 arity = get_irn_arity(node);
1679 for (i = 0; i < arity; ++i) {
1680 ir_node *op = get_irn_n(node, i);
1681 const arch_register_t *reg;
1682 if (!arch_irn_consider_in_reg_alloc(cls, op))
1685 reg = arch_get_irn_register(op);
1686 rbitset_set(forbidden_regs, arch_register_get_index(reg));
1689 /* free registers of values last used at this instruction */
1690 free_last_uses(&live_nodes, node);
1692 /* assign output registers */
1693 /* TODO: 2 phases: first: pre-assigned ones, 2nd real regs */
1694 be_foreach_definition(node, cls, value,
1695 assign_reg(block, value, forbidden_regs);
1699 ir_nodeset_destroy(&live_nodes);
1702 block_info->processed = true;
1704 /* permute values at end of predecessor blocks in case of phi-nodes */
1707 for (p = 0; p < n_preds; ++p) {
1708 add_phi_permutations(block, p);
1712 /* if we have exactly 1 successor then we might be able to produce phi
1714 if (get_irn_n_edges_kind(block, EDGE_KIND_BLOCK) == 1) {
1715 const ir_edge_t *edge
1716 = get_irn_out_edge_first_kind(block, EDGE_KIND_BLOCK);
1717 ir_node *succ = get_edge_src_irn(edge);
1718 int p = get_edge_src_pos(edge);
1719 block_info_t *succ_info = get_block_info(succ);
1721 if (succ_info->processed) {
1722 add_phi_permutations(succ, p);
1727 typedef struct block_costs_t block_costs_t;
1728 struct block_costs_t {
1729 float costs; /**< costs of the block */
1730 int dfs_num; /**< depth first search number (to detect backedges) */
1733 static int cmp_block_costs(const void *d1, const void *d2)
1735 const ir_node * const *block1 = d1;
1736 const ir_node * const *block2 = d2;
1737 const block_costs_t *info1 = get_irn_link(*block1);
1738 const block_costs_t *info2 = get_irn_link(*block2);
1739 return QSORT_CMP(info2->costs, info1->costs);
1742 static void determine_block_order(void)
1745 ir_node **blocklist = be_get_cfgpostorder(irg);
1746 int n_blocks = ARR_LEN(blocklist);
1748 pdeq *worklist = new_pdeq();
1749 ir_node **order = XMALLOCN(ir_node*, n_blocks);
1752 /* clear block links... */
1753 for (i = 0; i < n_blocks; ++i) {
1754 ir_node *block = blocklist[i];
1755 set_irn_link(block, NULL);
1758 /* walk blocks in reverse postorder, the costs for each block are the
1759 * sum of the costs of its predecessors (excluding the costs on backedges
1760 * which we can't determine) */
1761 for (i = n_blocks-1; i >= 0; --i) {
1762 block_costs_t *cost_info;
1763 ir_node *block = blocklist[i];
1765 float execfreq = (float)get_block_execfreq(execfreqs, block);
1766 float costs = execfreq;
1767 int n_cfgpreds = get_Block_n_cfgpreds(block);
1769 for (p = 0; p < n_cfgpreds; ++p) {
1770 ir_node *pred_block = get_Block_cfgpred_block(block, p);
1771 block_costs_t *pred_costs = get_irn_link(pred_block);
1772 /* we don't have any info for backedges */
1773 if (pred_costs == NULL)
1775 costs += pred_costs->costs;
1778 cost_info = OALLOCZ(&obst, block_costs_t);
1779 cost_info->costs = costs;
1780 cost_info->dfs_num = dfs_num++;
1781 set_irn_link(block, cost_info);
1784 /* sort array by block costs */
1785 qsort(blocklist, n_blocks, sizeof(blocklist[0]), cmp_block_costs);
1787 ir_reserve_resources(irg, IR_RESOURCE_BLOCK_VISITED);
1788 inc_irg_block_visited(irg);
1790 for (i = 0; i < n_blocks; ++i) {
1791 ir_node *block = blocklist[i];
1792 if (Block_block_visited(block))
1795 /* continually add predecessors with highest costs to worklist
1796 * (without using backedges) */
1798 block_costs_t *info = get_irn_link(block);
1799 ir_node *best_pred = NULL;
1800 float best_costs = -1;
1801 int n_cfgpred = get_Block_n_cfgpreds(block);
1804 pdeq_putr(worklist, block);
1805 mark_Block_block_visited(block);
1806 for (i = 0; i < n_cfgpred; ++i) {
1807 ir_node *pred_block = get_Block_cfgpred_block(block, i);
1808 block_costs_t *pred_info = get_irn_link(pred_block);
1810 /* ignore backedges */
1811 if (pred_info->dfs_num > info->dfs_num)
1814 if (info->costs > best_costs) {
1815 best_costs = info->costs;
1816 best_pred = pred_block;
1820 } while (block != NULL && !Block_block_visited(block));
1822 /* now put all nodes in the worklist in our final order */
1823 while (!pdeq_empty(worklist)) {
1824 ir_node *pblock = pdeq_getr(worklist);
1825 assert(order_p < n_blocks);
1826 order[order_p++] = pblock;
1829 assert(order_p == n_blocks);
1832 ir_free_resources(irg, IR_RESOURCE_BLOCK_VISITED);
1834 DEL_ARR_F(blocklist);
1836 obstack_free(&obst, NULL);
1837 obstack_init(&obst);
1839 block_order = order;
1840 n_block_order = n_blocks;
1844 * Run the register allocator for the current register class.
1846 static void be_pref_alloc_cls(void)
1850 lv = be_assure_liveness(irg);
1851 be_liveness_assure_sets(lv);
1853 ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
1855 DB((dbg, LEVEL_2, "=== Allocating registers of %s ===\n", cls->name));
1857 be_clear_links(irg);
1859 irg_block_walk_graph(irg, NULL, analyze_block, NULL);
1860 if (create_congruence_classes)
1861 combine_congruence_classes();
1863 for (i = 0; i < n_block_order; ++i) {
1864 ir_node *block = block_order[i];
1865 allocate_coalesce_block(block, NULL);
1868 ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
1871 static void dump(int mask, ir_graph *irg, const char *suffix)
1873 if (be_get_irg_options(irg)->dump_flags & mask)
1874 dump_ir_graph(irg, suffix);
1878 * Run the spiller on the current graph.
1880 static void spill(void)
1882 /* make sure all nodes show their real register pressure */
1883 be_timer_push(T_RA_CONSTR);
1884 be_pre_spill_prepare_constr(irg, cls);
1885 be_timer_pop(T_RA_CONSTR);
1887 dump(DUMP_RA, irg, "-spillprepare");
1890 be_timer_push(T_RA_SPILL);
1891 be_do_spill(irg, cls);
1892 be_timer_pop(T_RA_SPILL);
1894 be_timer_push(T_RA_SPILL_APPLY);
1895 check_for_memory_operands(irg);
1896 be_timer_pop(T_RA_SPILL_APPLY);
1898 dump(DUMP_RA, irg, "-spill");
1902 * The pref register allocator for a whole procedure.
1904 static void be_pref_alloc(ir_graph *new_irg)
1906 const arch_env_t *arch_env = be_get_irg_arch_env(new_irg);
1907 int n_cls = arch_env_get_n_reg_class(arch_env);
1910 obstack_init(&obst);
1913 execfreqs = be_get_irg_exec_freq(irg);
1915 /* determine a good coloring order */
1916 determine_block_order();
1918 for (c = 0; c < n_cls; ++c) {
1919 cls = arch_env_get_reg_class(arch_env, c);
1920 default_cls_req = NULL;
1921 if (arch_register_class_flags(cls) & arch_register_class_flag_manual_ra)
1924 stat_ev_ctx_push_str("regcls", cls->name);
1926 n_regs = arch_register_class_n_regs(cls);
1927 normal_regs = rbitset_malloc(n_regs);
1928 be_abi_set_non_ignore_regs(be_get_irg_abi(irg), cls, normal_regs);
1932 /* verify schedule and register pressure */
1933 be_timer_push(T_VERIFY);
1934 if (be_get_irg_options(irg)->verify_option == BE_VERIFY_WARN) {
1935 be_verify_schedule(irg);
1936 be_verify_register_pressure(irg, cls);
1937 } else if (be_get_irg_options(irg)->verify_option == BE_VERIFY_ASSERT) {
1938 assert(be_verify_schedule(irg) && "Schedule verification failed");
1939 assert(be_verify_register_pressure(irg, cls)
1940 && "Register pressure verification failed");
1942 be_timer_pop(T_VERIFY);
1944 be_timer_push(T_RA_COLOR);
1945 be_pref_alloc_cls();
1946 be_timer_pop(T_RA_COLOR);
1948 /* we most probably constructed new Phis so liveness info is invalid
1950 /* TODO: test liveness_introduce */
1951 be_liveness_invalidate(lv);
1954 stat_ev_ctx_pop("regcls");
1957 be_timer_push(T_RA_SPILL_APPLY);
1958 be_abi_fix_stack_nodes(irg);
1959 be_timer_pop(T_RA_SPILL_APPLY);
1961 be_timer_push(T_VERIFY);
1962 if (be_get_irg_options(irg)->verify_option == BE_VERIFY_WARN) {
1963 be_verify_register_allocation(irg);
1964 } else if (be_get_irg_options(irg)->verify_option == BE_VERIFY_ASSERT) {
1965 assert(be_verify_register_allocation(irg)
1966 && "Register allocation invalid");
1968 be_timer_pop(T_VERIFY);
1970 obstack_free(&obst, NULL);
1973 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_pref_alloc);
1974 void be_init_pref_alloc(void)
1976 static be_ra_t be_ra_pref = {
1979 lc_opt_entry_t *be_grp = lc_opt_get_grp(firm_opt_get_root(), "be");
1980 lc_opt_entry_t *prefalloc_group = lc_opt_get_grp(be_grp, "prefalloc");
1981 lc_opt_add_table(prefalloc_group, options);
1983 be_register_allocator("pref", &be_ra_pref);
1984 FIRM_DBG_REGISTER(dbg, "firm.be.prefalloc");