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 const arch_register_req_t *req = arch_get_register_req_out(op);
376 /* last usage of a value? */
377 if (!ir_nodeset_contains(&live_nodes, op)) {
378 rbitset_set(info->last_uses, i);
382 be_liveness_transfer(cls, node, &live_nodes);
384 if (create_preferences) {
385 /* update weights based on usage constraints */
386 for (i = 0; i < arity; ++i) {
387 const arch_register_req_t *req;
388 const unsigned *limited;
389 ir_node *op = get_irn_n(node, i);
391 if (!arch_irn_consider_in_reg_alloc(cls, op))
394 req = arch_get_register_req(node, i);
395 if (!(req->type & arch_register_req_type_limited))
398 limited = req->limited;
399 give_penalties_for_limits(&live_nodes, weight * USE_FACTOR,
405 ir_nodeset_destroy(&live_nodes);
408 static void congruence_def(ir_nodeset_t *live_nodes, const ir_node *node)
410 const arch_register_req_t *req = arch_get_register_req_out(node);
412 /* should be same constraint? */
413 if (req->type & arch_register_req_type_should_be_same) {
414 const ir_node *insn = skip_Proj_const(node);
415 int arity = get_irn_arity(insn);
417 unsigned node_idx = get_irn_idx(node);
418 node_idx = uf_find(congruence_classes, node_idx);
420 for (i = 0; i < arity; ++i) {
424 ir_nodeset_iterator_t iter;
425 bool interferes = false;
427 if (!rbitset_is_set(&req->other_same, i))
430 op = get_irn_n(insn, i);
431 op_idx = get_irn_idx(op);
432 op_idx = uf_find(congruence_classes, op_idx);
434 /* do we interfere with the value */
435 foreach_ir_nodeset(live_nodes, live, iter) {
436 int lv_idx = get_irn_idx(live);
437 lv_idx = uf_find(congruence_classes, lv_idx);
438 if (lv_idx == op_idx) {
443 /* don't put in same affinity class if we interfere */
447 node_idx = uf_union(congruence_classes, node_idx, op_idx);
448 DB((dbg, LEVEL_3, "Merge %+F and %+F congruence classes\n",
450 /* one should_be_same is enough... */
456 static void create_congruence_class(ir_node *block, void *data)
458 ir_nodeset_t live_nodes;
462 ir_nodeset_init(&live_nodes);
463 be_liveness_end_of_block(lv, cls, block, &live_nodes);
465 /* check should be same constraints */
466 sched_foreach_reverse(block, node) {
471 be_foreach_definition(node, cls, value,
472 congruence_def(&live_nodes, value);
474 be_liveness_transfer(cls, node, &live_nodes);
477 /* check phi congruence classes */
478 sched_foreach_reverse_from(node, node) {
482 assert(is_Phi(node));
484 if (!arch_irn_consider_in_reg_alloc(cls, node))
487 node_idx = get_irn_idx(node);
488 node_idx = uf_find(congruence_classes, node_idx);
490 arity = get_irn_arity(node);
491 for (i = 0; i < arity; ++i) {
492 bool interferes = false;
493 ir_nodeset_iterator_t iter;
498 allocation_info_t *head_info;
499 allocation_info_t *other_info;
500 ir_node *op = get_Phi_pred(node, i);
501 int op_idx = get_irn_idx(op);
502 op_idx = uf_find(congruence_classes, op_idx);
504 /* do we interfere with the value */
505 foreach_ir_nodeset(&live_nodes, live, iter) {
506 int lv_idx = get_irn_idx(live);
507 lv_idx = uf_find(congruence_classes, lv_idx);
508 if (lv_idx == op_idx) {
513 /* don't put in same affinity class if we interfere */
516 /* any other phi has the same input? */
517 sched_foreach(block, phi) {
522 if (!arch_irn_consider_in_reg_alloc(cls, phi))
524 oop = get_Phi_pred(phi, i);
527 oop_idx = get_irn_idx(oop);
528 oop_idx = uf_find(congruence_classes, oop_idx);
529 if (oop_idx == op_idx) {
537 /* merge the 2 congruence classes and sum up their preferences */
538 old_node_idx = node_idx;
539 node_idx = uf_union(congruence_classes, node_idx, op_idx);
540 DB((dbg, LEVEL_3, "Merge %+F and %+F congruence classes\n",
543 old_node_idx = node_idx == old_node_idx ? op_idx : old_node_idx;
544 head_info = get_allocation_info(get_idx_irn(irg, node_idx));
545 other_info = get_allocation_info(get_idx_irn(irg, old_node_idx));
546 for (r = 0; r < n_regs; ++r) {
547 head_info->prefs[r] += other_info->prefs[r];
553 static void set_congruence_prefs(ir_node *node, void *data)
555 allocation_info_t *info;
556 allocation_info_t *head_info;
557 unsigned node_idx = get_irn_idx(node);
558 unsigned node_set = uf_find(congruence_classes, node_idx);
562 /* head of congruence class or not in any class */
563 if (node_set == node_idx)
566 if (!arch_irn_consider_in_reg_alloc(cls, node))
569 head_info = get_allocation_info(get_idx_irn(irg, node_set));
570 info = get_allocation_info(node);
572 memcpy(info->prefs, head_info->prefs, n_regs * sizeof(info->prefs[0]));
575 static void combine_congruence_classes(void)
577 size_t n = get_irg_last_idx(irg);
578 congruence_classes = XMALLOCN(int, n);
579 uf_init(congruence_classes, n);
581 /* create congruence classes */
582 irg_block_walk_graph(irg, create_congruence_class, NULL, NULL);
583 /* merge preferences */
584 irg_walk_graph(irg, set_congruence_prefs, NULL, NULL);
585 free(congruence_classes);
591 * Assign register reg to the given node.
593 * @param node the node
594 * @param reg the register
596 static void use_reg(ir_node *node, const arch_register_t *reg)
598 unsigned r = arch_register_get_index(reg);
599 assignments[r] = node;
600 arch_set_irn_register(node, reg);
603 static void free_reg_of_value(ir_node *node)
605 const arch_register_t *reg;
608 if (!arch_irn_consider_in_reg_alloc(cls, node))
611 reg = arch_get_irn_register(node);
612 r = arch_register_get_index(reg);
613 /* assignment->value may be NULL if a value is used at 2 inputs
614 so it gets freed twice. */
615 assert(assignments[r] == node || assignments[r] == NULL);
616 assignments[r] = NULL;
620 * Compare two register preferences in decreasing order.
622 static int compare_reg_pref(const void *e1, const void *e2)
624 const reg_pref_t *rp1 = (const reg_pref_t*) e1;
625 const reg_pref_t *rp2 = (const reg_pref_t*) e2;
626 if (rp1->pref < rp2->pref)
628 if (rp1->pref > rp2->pref)
633 static void fill_sort_candidates(reg_pref_t *regprefs,
634 const allocation_info_t *info)
638 for (r = 0; r < n_regs; ++r) {
639 float pref = info->prefs[r];
641 regprefs[r].pref = pref;
643 /* TODO: use a stable sort here to avoid unnecessary register jumping */
644 qsort(regprefs, n_regs, sizeof(regprefs[0]), compare_reg_pref);
647 static bool try_optimistic_split(ir_node *to_split, ir_node *before,
648 float pref, float pref_delta,
649 unsigned *forbidden_regs, int recursion)
651 const arch_register_t *from_reg;
652 const arch_register_t *reg;
653 ir_node *original_insn;
659 allocation_info_t *info = get_allocation_info(to_split);
662 float split_threshold;
666 /* stupid hack: don't optimisticallt split don't spill nodes...
667 * (so we don't split away the values produced because of
668 * must_be_different constraints) */
669 original_insn = skip_Proj(info->original_value);
670 if (arch_irn_get_flags(original_insn) & arch_irn_flags_dont_spill)
673 from_reg = arch_get_irn_register(to_split);
674 from_r = arch_register_get_index(from_reg);
675 block = get_nodes_block(before);
676 split_threshold = (float)get_block_execfreq(execfreqs, block) * SPLIT_DELTA;
678 if (pref_delta < split_threshold*0.5)
681 /* find the best free position where we could move to */
682 prefs = ALLOCAN(reg_pref_t, n_regs);
683 fill_sort_candidates(prefs, info);
684 for (i = 0; i < n_regs; ++i) {
688 bool old_source_state;
690 /* we need a normal register which is not an output register
691 an different from the current register of to_split */
693 if (!rbitset_is_set(normal_regs, r))
695 if (rbitset_is_set(forbidden_regs, r))
700 /* is the split worth it? */
701 delta = pref_delta + prefs[i].pref;
702 if (delta < split_threshold) {
703 DB((dbg, LEVEL_3, "Not doing optimistical split of %+F (depth %d), win %f too low\n",
704 to_split, recursion, delta));
708 /* if the register is free then we can do the split */
709 if (assignments[r] == NULL)
712 /* otherwise we might try recursively calling optimistic_split */
713 if (recursion+1 > MAX_OPTIMISTIC_SPLIT_RECURSION)
716 apref = prefs[i].pref;
717 apref_delta = i+1 < n_regs ? apref - prefs[i+1].pref : 0;
718 apref_delta += pref_delta - split_threshold;
720 /* our source register isn't a useful destination for recursive
722 old_source_state = rbitset_is_set(forbidden_regs, from_r);
723 rbitset_set(forbidden_regs, from_r);
724 /* try recursive split */
725 res = try_optimistic_split(assignments[r], before, apref,
726 apref_delta, forbidden_regs, recursion+1);
727 /* restore our destination */
728 if (old_source_state) {
729 rbitset_set(forbidden_regs, from_r);
731 rbitset_clear(forbidden_regs, from_r);
740 reg = arch_register_for_index(cls, r);
741 copy = be_new_Copy(cls, block, to_split);
742 mark_as_copy_of(copy, to_split);
743 /* hacky, but correct here */
744 if (assignments[arch_register_get_index(from_reg)] == to_split)
745 free_reg_of_value(to_split);
747 sched_add_before(before, copy);
750 "Optimistic live-range split %+F move %+F(%s) -> %s before %+F (win %f, depth %d)\n",
751 copy, to_split, from_reg->name, reg->name, before, delta, recursion));
756 * Determine and assign a register for node @p node
758 static void assign_reg(const ir_node *block, ir_node *node,
759 unsigned *forbidden_regs)
761 const arch_register_t *reg;
762 allocation_info_t *info;
763 const arch_register_req_t *req;
764 reg_pref_t *reg_prefs;
767 const unsigned *allowed_regs;
770 assert(!is_Phi(node));
771 /* preassigned register? */
772 reg = arch_get_irn_register(node);
774 DB((dbg, LEVEL_2, "Preassignment %+F -> %s\n", node, reg->name));
779 req = arch_get_register_req_out(node);
780 /* ignore reqs must be preassigned */
781 assert (! (req->type & arch_register_req_type_ignore));
783 /* give should_be_same boni */
784 info = get_allocation_info(node);
785 in_node = skip_Proj(node);
786 if (req->type & arch_register_req_type_should_be_same) {
787 float weight = (float)get_block_execfreq(execfreqs, block);
788 int arity = get_irn_arity(in_node);
791 assert(arity <= (int) sizeof(req->other_same) * 8);
792 for (i = 0; i < arity; ++i) {
794 const arch_register_t *reg;
796 if (!rbitset_is_set(&req->other_same, i))
799 in = get_irn_n(in_node, i);
800 reg = arch_get_irn_register(in);
802 r = arch_register_get_index(reg);
804 /* if the value didn't die here then we should not propagate the
805 * should_be_same info */
806 if (assignments[r] == in)
809 info->prefs[r] += weight * AFF_SHOULD_BE_SAME;
813 /* create list of register candidates and sort by their preference */
814 DB((dbg, LEVEL_2, "Candidates for %+F:", node));
815 reg_prefs = alloca(n_regs * sizeof(reg_prefs[0]));
816 fill_sort_candidates(reg_prefs, info);
817 for (i = 0; i < n_regs; ++i) {
818 unsigned num = reg_prefs[i].num;
819 const arch_register_t *reg;
821 if (!rbitset_is_set(normal_regs, num))
824 reg = arch_register_for_index(cls, num);
825 DB((dbg, LEVEL_2, " %s(%f)", reg->name, reg_prefs[i].pref));
827 DB((dbg, LEVEL_2, "\n"));
829 allowed_regs = normal_regs;
830 if (req->type & arch_register_req_type_limited) {
831 allowed_regs = req->limited;
834 for (i = 0; i < n_regs; ++i) {
839 r = reg_prefs[i].num;
840 if (!rbitset_is_set(allowed_regs, r))
842 if (assignments[r] == NULL)
844 pref = reg_prefs[i].pref;
845 delta = i+1 < n_regs ? pref - reg_prefs[i+1].pref : 0;
846 before = skip_Proj(node);
847 res = try_optimistic_split(assignments[r], before,
848 pref, delta, forbidden_regs, 0);
853 /* the common reason to hit this panic is when 1 of your nodes is not
854 * register pressure faithful */
855 panic("No register left for %+F\n", node);
858 reg = arch_register_for_index(cls, r);
859 DB((dbg, LEVEL_2, "Assign %+F -> %s\n", node, reg->name));
864 * Add an permutation in front of a node and change the assignments
865 * due to this permutation.
867 * To understand this imagine a permutation like this:
877 * First we count how many destinations a single value has. At the same time
878 * we can be sure that each destination register has at most 1 source register
879 * (it can have 0 which means we don't care what value is in it).
880 * We ignore all fullfilled permuations (like 7->7)
881 * In a first pass we create as much copy instructions as possible as they
882 * are generally cheaper than exchanges. We do this by counting into how many
883 * destinations a register has to be copied (in the example it's 2 for register
884 * 3, or 1 for the registers 1,2,4 and 7).
885 * We can then create a copy into every destination register when the usecount
886 * of that register is 0 (= noone else needs the value in the register).
888 * After this step we should have cycles left. We implement a cyclic permutation
889 * of n registers with n-1 transpositions.
891 * @param live_nodes the set of live nodes, updated due to live range split
892 * @param before the node before we add the permutation
893 * @param permutation the permutation array indices are the destination
894 * registers, the values in the array are the source
897 static void permute_values(ir_nodeset_t *live_nodes, ir_node *before,
898 unsigned *permutation)
900 unsigned *n_used = ALLOCANZ(unsigned, n_regs);
904 /* determine how often each source register needs to be read */
905 for (r = 0; r < n_regs; ++r) {
906 unsigned old_reg = permutation[r];
909 value = assignments[old_reg];
911 /* nothing to do here, reg is not live. Mark it as fixpoint
912 * so we ignore it in the next steps */
920 block = get_nodes_block(before);
922 /* step1: create copies where immediately possible */
923 for (r = 0; r < n_regs; /* empty */) {
926 const arch_register_t *reg;
927 unsigned old_r = permutation[r];
929 /* - no need to do anything for fixed points.
930 - we can't copy if the value in the dest reg is still needed */
931 if (old_r == r || n_used[r] > 0) {
937 src = assignments[old_r];
938 copy = be_new_Copy(cls, block, src);
939 sched_add_before(before, copy);
940 reg = arch_register_for_index(cls, r);
941 DB((dbg, LEVEL_2, "Copy %+F (from %+F, before %+F) -> %s\n",
942 copy, src, before, reg->name));
943 mark_as_copy_of(copy, src);
946 if (live_nodes != NULL) {
947 ir_nodeset_insert(live_nodes, copy);
950 /* old register has 1 user less, permutation is resolved */
951 assert(arch_register_get_index(arch_get_irn_register(src)) == old_r);
954 assert(n_used[old_r] > 0);
956 if (n_used[old_r] == 0) {
957 if (live_nodes != NULL) {
958 ir_nodeset_remove(live_nodes, src);
960 free_reg_of_value(src);
963 /* advance or jump back (if this copy enabled another copy) */
964 if (old_r < r && n_used[old_r] == 0) {
971 /* at this point we only have "cycles" left which we have to resolve with
973 * TODO: if we have free registers left, then we should really use copy
974 * instructions for any cycle longer than 2 registers...
975 * (this is probably architecture dependent, there might be archs where
976 * copies are preferable even for 2-cycles) */
978 /* create perms with the rest */
979 for (r = 0; r < n_regs; /* empty */) {
980 const arch_register_t *reg;
981 unsigned old_r = permutation[r];
993 /* we shouldn't have copies from 1 value to multiple destinations left*/
994 assert(n_used[old_r] == 1);
996 /* exchange old_r and r2; after that old_r is a fixed point */
997 r2 = permutation[old_r];
999 in[0] = assignments[r2];
1000 in[1] = assignments[old_r];
1001 perm = be_new_Perm(cls, block, 2, in);
1002 sched_add_before(before, perm);
1003 DB((dbg, LEVEL_2, "Perm %+F (perm %+F,%+F, before %+F)\n",
1004 perm, in[0], in[1], before));
1006 proj0 = new_r_Proj(perm, get_irn_mode(in[0]), 0);
1007 mark_as_copy_of(proj0, in[0]);
1008 reg = arch_register_for_index(cls, old_r);
1009 use_reg(proj0, reg);
1011 proj1 = new_r_Proj(perm, get_irn_mode(in[1]), 1);
1012 mark_as_copy_of(proj1, in[1]);
1013 reg = arch_register_for_index(cls, r2);
1014 use_reg(proj1, reg);
1016 /* 1 value is now in the correct register */
1017 permutation[old_r] = old_r;
1018 /* the source of r changed to r2 */
1019 permutation[r] = r2;
1021 /* if we have reached a fixpoint update data structures */
1022 if (live_nodes != NULL) {
1023 ir_nodeset_remove(live_nodes, in[0]);
1024 ir_nodeset_remove(live_nodes, in[1]);
1025 ir_nodeset_remove(live_nodes, proj0);
1026 ir_nodeset_insert(live_nodes, proj1);
1030 #ifdef DEBUG_libfirm
1031 /* now we should only have fixpoints left */
1032 for (r = 0; r < n_regs; ++r) {
1033 assert(permutation[r] == r);
1039 * Free regs for values last used.
1041 * @param live_nodes set of live nodes, will be updated
1042 * @param node the node to consider
1044 static void free_last_uses(ir_nodeset_t *live_nodes, ir_node *node)
1046 allocation_info_t *info = get_allocation_info(node);
1047 const unsigned *last_uses = info->last_uses;
1048 int arity = get_irn_arity(node);
1051 for (i = 0; i < arity; ++i) {
1054 /* check if one operand is the last use */
1055 if (!rbitset_is_set(last_uses, i))
1058 op = get_irn_n(node, i);
1059 free_reg_of_value(op);
1060 ir_nodeset_remove(live_nodes, op);
1065 * change inputs of a node to the current value (copies/perms)
1067 static void rewire_inputs(ir_node *node)
1070 int arity = get_irn_arity(node);
1072 for (i = 0; i < arity; ++i) {
1073 ir_node *op = get_irn_n(node, i);
1074 allocation_info_t *info = try_get_allocation_info(op);
1079 info = get_allocation_info(info->original_value);
1080 if (info->current_value != op) {
1081 set_irn_n(node, i, info->current_value);
1087 * Create a bitset of registers occupied with value living through an
1090 static void determine_live_through_regs(unsigned *bitset, ir_node *node)
1092 const allocation_info_t *info = get_allocation_info(node);
1097 /* mark all used registers as potentially live-through */
1098 for (r = 0; r < n_regs; ++r) {
1099 if (assignments[r] == NULL)
1101 if (!rbitset_is_set(normal_regs, r))
1104 rbitset_set(bitset, r);
1107 /* remove registers of value dying at the instruction */
1108 arity = get_irn_arity(node);
1109 for (i = 0; i < arity; ++i) {
1111 const arch_register_t *reg;
1113 if (!rbitset_is_set(info->last_uses, i))
1116 op = get_irn_n(node, i);
1117 reg = arch_get_irn_register(op);
1118 rbitset_clear(bitset, arch_register_get_index(reg));
1123 * Enforce constraints at a node by live range splits.
1125 * @param live_nodes the set of live nodes, might be changed
1126 * @param node the current node
1128 static void enforce_constraints(ir_nodeset_t *live_nodes, ir_node *node,
1129 unsigned *forbidden_regs)
1131 int arity = get_irn_arity(node);
1133 hungarian_problem_t *bp;
1135 unsigned *assignment;
1138 /* construct a list of register occupied by live-through values */
1139 unsigned *live_through_regs = NULL;
1141 /* see if any use constraints are not met */
1143 for (i = 0; i < arity; ++i) {
1144 ir_node *op = get_irn_n(node, i);
1145 const arch_register_t *reg;
1146 const arch_register_req_t *req;
1147 const unsigned *limited;
1150 if (!arch_irn_consider_in_reg_alloc(cls, op))
1153 /* are there any limitations for the i'th operand? */
1154 req = arch_get_register_req(node, i);
1155 if (!(req->type & arch_register_req_type_limited))
1158 limited = req->limited;
1159 reg = arch_get_irn_register(op);
1160 r = arch_register_get_index(reg);
1161 if (!rbitset_is_set(limited, r)) {
1162 /* found an assignment outside the limited set */
1168 /* is any of the live-throughs using a constrained output register? */
1169 be_foreach_definition(node, cls, value,
1170 if (! (req_->type & arch_register_req_type_limited))
1172 if (live_through_regs == NULL) {
1173 rbitset_alloca(live_through_regs, n_regs);
1174 determine_live_through_regs(live_through_regs, node);
1176 rbitset_or(forbidden_regs, req_->limited, n_regs);
1177 if (rbitsets_have_common(req_->limited, live_through_regs, n_regs))
1184 /* create these arrays if we haven't yet */
1185 if (live_through_regs == NULL) {
1186 rbitset_alloca(live_through_regs, n_regs);
1189 /* at this point we have to construct a bipartite matching problem to see
1190 * which values should go to which registers
1191 * Note: We're building the matrix in "reverse" - source registers are
1192 * right, destinations left because this will produce the solution
1193 * in the format required for permute_values.
1195 bp = hungarian_new(n_regs, n_regs, HUNGARIAN_MATCH_PERFECT);
1197 /* add all combinations, then remove not allowed ones */
1198 for (l = 0; l < n_regs; ++l) {
1199 if (!rbitset_is_set(normal_regs, l)) {
1200 hungarian_add(bp, l, l, 1);
1204 for (r = 0; r < n_regs; ++r) {
1205 if (!rbitset_is_set(normal_regs, r))
1207 /* livethrough values may not use constrainted output registers */
1208 if (rbitset_is_set(live_through_regs, l)
1209 && rbitset_is_set(forbidden_regs, r))
1212 hungarian_add(bp, r, l, l == r ? 9 : 8);
1216 for (i = 0; i < arity; ++i) {
1217 ir_node *op = get_irn_n(node, i);
1218 const arch_register_t *reg;
1219 const arch_register_req_t *req;
1220 const unsigned *limited;
1221 unsigned current_reg;
1223 if (!arch_irn_consider_in_reg_alloc(cls, op))
1226 req = arch_get_register_req(node, i);
1227 if (!(req->type & arch_register_req_type_limited))
1230 limited = req->limited;
1231 reg = arch_get_irn_register(op);
1232 current_reg = arch_register_get_index(reg);
1233 for (r = 0; r < n_regs; ++r) {
1234 if (rbitset_is_set(limited, r))
1236 hungarian_remove(bp, r, current_reg);
1240 //hungarian_print_cost_matrix(bp, 1);
1241 hungarian_prepare_cost_matrix(bp, HUNGARIAN_MODE_MAXIMIZE_UTIL);
1243 assignment = ALLOCAN(unsigned, n_regs);
1244 res = hungarian_solve(bp, assignment, NULL, 0);
1248 fprintf(stderr, "Swap result:");
1249 for (i = 0; i < (int) n_regs; ++i) {
1250 fprintf(stderr, " %d", assignment[i]);
1252 fprintf(stderr, "\n");
1257 permute_values(live_nodes, node, assignment);
1260 /** test wether a node @p n is a copy of the value of node @p of */
1261 static bool is_copy_of(ir_node *value, ir_node *test_value)
1263 allocation_info_t *test_info;
1264 allocation_info_t *info;
1266 if (value == test_value)
1269 info = get_allocation_info(value);
1270 test_info = get_allocation_info(test_value);
1271 return test_info->original_value == info->original_value;
1275 * find a value in the end-assignment of a basic block
1276 * @returns the index into the assignment array if found
1279 static int find_value_in_block_info(block_info_t *info, ir_node *value)
1282 ir_node **assignments = info->assignments;
1283 for (r = 0; r < n_regs; ++r) {
1284 ir_node *a_value = assignments[r];
1286 if (a_value == NULL)
1288 if (is_copy_of(a_value, value))
1296 * Create the necessary permutations at the end of a basic block to fullfill
1297 * the register assignment for phi-nodes in the next block
1299 static void add_phi_permutations(ir_node *block, int p)
1302 unsigned *permutation;
1303 ir_node **old_assignments;
1304 bool need_permutation;
1306 ir_node *pred = get_Block_cfgpred_block(block, p);
1308 block_info_t *pred_info = get_block_info(pred);
1310 /* predecessor not processed yet? nothing to do */
1311 if (!pred_info->processed)
1314 permutation = ALLOCAN(unsigned, n_regs);
1315 for (r = 0; r < n_regs; ++r) {
1319 /* check phi nodes */
1320 need_permutation = false;
1321 phi = sched_first(block);
1322 for ( ; is_Phi(phi); phi = sched_next(phi)) {
1323 const arch_register_t *reg;
1324 const arch_register_t *op_reg;
1329 if (!arch_irn_consider_in_reg_alloc(cls, phi))
1332 op = get_Phi_pred(phi, p);
1333 a = find_value_in_block_info(pred_info, op);
1336 reg = arch_get_irn_register(phi);
1337 regn = arch_register_get_index(reg);
1338 /* same register? nothing to do */
1342 op = pred_info->assignments[a];
1343 op_reg = arch_get_irn_register(op);
1344 /* virtual or joker registers are ok too */
1345 if ((op_reg->type & arch_register_type_joker)
1346 || (op_reg->type & arch_register_type_virtual))
1349 permutation[regn] = a;
1350 need_permutation = true;
1353 if (need_permutation) {
1354 /* permute values at end of predecessor */
1355 old_assignments = assignments;
1356 assignments = pred_info->assignments;
1357 permute_values(NULL, be_get_end_of_block_insertion_point(pred),
1359 assignments = old_assignments;
1362 /* change phi nodes to use the copied values */
1363 phi = sched_first(block);
1364 for ( ; is_Phi(phi); phi = sched_next(phi)) {
1368 if (!arch_irn_consider_in_reg_alloc(cls, phi))
1371 op = get_Phi_pred(phi, p);
1373 /* we have permuted all values into the correct registers so we can
1374 simply query which value occupies the phis register in the
1376 a = arch_register_get_index(arch_get_irn_register(phi));
1377 op = pred_info->assignments[a];
1378 set_Phi_pred(phi, p, op);
1383 * Set preferences for a phis register based on the registers used on the
1386 static void adapt_phi_prefs(ir_node *phi)
1389 int arity = get_irn_arity(phi);
1390 ir_node *block = get_nodes_block(phi);
1391 allocation_info_t *info = get_allocation_info(phi);
1393 for (i = 0; i < arity; ++i) {
1394 ir_node *op = get_irn_n(phi, i);
1395 const arch_register_t *reg = arch_get_irn_register(op);
1396 ir_node *pred_block;
1397 block_info_t *pred_block_info;
1403 /* we only give the bonus if the predecessor already has registers
1404 * assigned, otherwise we only see a dummy value
1405 * and any conclusions about its register are useless */
1406 pred_block = get_Block_cfgpred_block(block, i);
1407 pred_block_info = get_block_info(pred_block);
1408 if (!pred_block_info->processed)
1411 /* give bonus for already assigned register */
1412 weight = (float)get_block_execfreq(execfreqs, pred_block);
1413 r = arch_register_get_index(reg);
1414 info->prefs[r] += weight * AFF_PHI;
1419 * After a phi has been assigned a register propagate preference inputs
1420 * to the phi inputs.
1422 static void propagate_phi_register(ir_node *phi, unsigned assigned_r)
1425 ir_node *block = get_nodes_block(phi);
1426 int arity = get_irn_arity(phi);
1428 for (i = 0; i < arity; ++i) {
1429 ir_node *op = get_Phi_pred(phi, i);
1430 allocation_info_t *info = get_allocation_info(op);
1431 ir_node *pred_block = get_Block_cfgpred_block(block, i);
1434 = (float)get_block_execfreq(execfreqs, pred_block) * AFF_PHI;
1436 if (info->prefs[assigned_r] >= weight)
1439 /* promote the prefered register */
1440 for (r = 0; r < n_regs; ++r) {
1441 if (info->prefs[r] > -weight) {
1442 info->prefs[r] = -weight;
1445 info->prefs[assigned_r] = weight;
1448 propagate_phi_register(op, assigned_r);
1452 static void assign_phi_registers(ir_node *block)
1457 unsigned *assignment;
1459 hungarian_problem_t *bp;
1461 /* count phi nodes */
1462 sched_foreach(block, node) {
1465 if (!arch_irn_consider_in_reg_alloc(cls, node))
1473 /* build a bipartite matching problem for all phi nodes */
1474 bp = hungarian_new(n_phis, n_regs, HUNGARIAN_MATCH_PERFECT);
1476 sched_foreach(block, node) {
1479 allocation_info_t *info;
1482 if (!arch_irn_consider_in_reg_alloc(cls, node))
1485 /* give boni for predecessor colorings */
1486 adapt_phi_prefs(node);
1487 /* add stuff to bipartite problem */
1488 info = get_allocation_info(node);
1489 DB((dbg, LEVEL_3, "Prefs for %+F: ", node));
1490 for (r = 0; r < n_regs; ++r) {
1493 if (!rbitset_is_set(normal_regs, r))
1496 costs = info->prefs[r];
1497 costs = costs < 0 ? -logf(-costs+1) : logf(costs+1);
1500 hungarian_add(bp, n, r, (int)costs);
1501 DB((dbg, LEVEL_3, " %s(%f)", arch_register_for_index(cls, r)->name,
1504 DB((dbg, LEVEL_3, "\n"));
1508 //hungarian_print_cost_matrix(bp, 7);
1509 hungarian_prepare_cost_matrix(bp, HUNGARIAN_MODE_MAXIMIZE_UTIL);
1511 assignment = ALLOCAN(unsigned, n_regs);
1512 res = hungarian_solve(bp, assignment, NULL, 0);
1517 sched_foreach(block, node) {
1519 const arch_register_t *reg;
1523 if (!arch_irn_consider_in_reg_alloc(cls, node))
1526 r = assignment[n++];
1527 assert(rbitset_is_set(normal_regs, r));
1528 reg = arch_register_for_index(cls, r);
1529 DB((dbg, LEVEL_2, "Assign %+F -> %s\n", node, reg->name));
1532 /* adapt preferences for phi inputs */
1533 if (propagate_phi_registers)
1534 propagate_phi_register(node, r);
1539 * Walker: assign registers to all nodes of a block that
1540 * need registers from the currently considered register class.
1542 static void allocate_coalesce_block(ir_node *block, void *data)
1545 ir_nodeset_t live_nodes;
1548 block_info_t *block_info;
1549 block_info_t **pred_block_infos;
1551 unsigned *forbidden_regs; /**< collects registers which must
1552 not be used for optimistic splits */
1555 DB((dbg, LEVEL_2, "* Block %+F\n", block));
1557 /* clear assignments */
1558 block_info = get_block_info(block);
1559 assignments = block_info->assignments;
1561 ir_nodeset_init(&live_nodes);
1563 /* gather regalloc infos of predecessor blocks */
1564 n_preds = get_Block_n_cfgpreds(block);
1565 pred_block_infos = ALLOCAN(block_info_t*, n_preds);
1566 for (i = 0; i < n_preds; ++i) {
1567 ir_node *pred = get_Block_cfgpred_block(block, i);
1568 block_info_t *pred_info = get_block_info(pred);
1569 pred_block_infos[i] = pred_info;
1572 phi_ins = ALLOCAN(ir_node*, n_preds);
1574 /* collect live-in nodes and preassigned values */
1575 be_lv_foreach(lv, block, be_lv_state_in, i) {
1576 bool need_phi = false;
1577 const arch_register_req_t *req;
1578 const arch_register_t *reg;
1581 node = be_lv_get_irn(lv, block, i);
1582 req = arch_get_register_req_out(node);
1583 if (req->cls != cls)
1586 if (req->type & arch_register_req_type_ignore) {
1587 allocation_info_t *info = get_allocation_info(node);
1588 info->current_value = node;
1590 reg = arch_get_irn_register(node);
1591 assert(reg != NULL); /* ignore values must be preassigned */
1596 /* check all predecessors for this value, if it is not everywhere the
1597 same or unknown then we have to construct a phi
1598 (we collect the potential phi inputs here) */
1599 for (p = 0; p < n_preds; ++p) {
1600 block_info_t *pred_info = pred_block_infos[p];
1602 if (!pred_info->processed) {
1603 /* use node for now, it will get fixed later */
1607 int a = find_value_in_block_info(pred_info, node);
1609 /* must live out of predecessor */
1611 phi_ins[p] = pred_info->assignments[a];
1612 /* different value from last time? then we need a phi */
1613 if (p > 0 && phi_ins[p-1] != phi_ins[p]) {
1620 ir_mode *mode = get_irn_mode(node);
1621 const arch_register_req_t *req = get_default_req_current_cls();
1624 phi = new_r_Phi(block, n_preds, phi_ins, mode);
1625 be_set_phi_reg_req(phi, req);
1627 DB((dbg, LEVEL_3, "Create Phi %+F (for %+F) -", phi, node));
1628 #ifdef DEBUG_libfirm
1631 for (i = 0; i < n_preds; ++i) {
1632 DB((dbg, LEVEL_3, " %+F", phi_ins[i]));
1634 DB((dbg, LEVEL_3, "\n"));
1637 mark_as_copy_of(phi, node);
1638 sched_add_after(block, phi);
1642 allocation_info_t *info = get_allocation_info(node);
1643 info->current_value = phi_ins[0];
1645 /* Grab 1 of the inputs we constructed (might not be the same as
1646 * "node" as we could see the same copy of the value in all
1651 /* if the node already has a register assigned use it */
1652 reg = arch_get_irn_register(node);
1657 /* remember that this node is live at the beginning of the block */
1658 ir_nodeset_insert(&live_nodes, node);
1661 rbitset_alloca(forbidden_regs, n_regs);
1663 /* handle phis... */
1664 assign_phi_registers(block);
1666 /* all live-ins must have a register */
1667 #ifdef DEBUG_libfirm
1669 ir_nodeset_iterator_t iter;
1670 foreach_ir_nodeset(&live_nodes, node, iter) {
1671 const arch_register_t *reg = arch_get_irn_register(node);
1672 assert(reg != NULL);
1677 /* assign instructions in the block */
1678 sched_foreach(block, node) {
1683 /* phis are already assigned */
1687 rewire_inputs(node);
1689 /* enforce use constraints */
1690 rbitset_clear_all(forbidden_regs, n_regs);
1691 enforce_constraints(&live_nodes, node, forbidden_regs);
1693 rewire_inputs(node);
1695 /* we may not use registers used for inputs for optimistic splits */
1696 arity = get_irn_arity(node);
1697 for (i = 0; i < arity; ++i) {
1698 ir_node *op = get_irn_n(node, i);
1699 const arch_register_t *reg;
1700 if (!arch_irn_consider_in_reg_alloc(cls, op))
1703 reg = arch_get_irn_register(op);
1704 rbitset_set(forbidden_regs, arch_register_get_index(reg));
1707 /* free registers of values last used at this instruction */
1708 free_last_uses(&live_nodes, node);
1710 /* assign output registers */
1711 be_foreach_definition_(node, cls, value,
1712 assign_reg(block, value, forbidden_regs);
1716 ir_nodeset_destroy(&live_nodes);
1719 block_info->processed = true;
1721 /* permute values at end of predecessor blocks in case of phi-nodes */
1724 for (p = 0; p < n_preds; ++p) {
1725 add_phi_permutations(block, p);
1729 /* if we have exactly 1 successor then we might be able to produce phi
1731 if (get_irn_n_edges_kind(block, EDGE_KIND_BLOCK) == 1) {
1732 const ir_edge_t *edge
1733 = get_irn_out_edge_first_kind(block, EDGE_KIND_BLOCK);
1734 ir_node *succ = get_edge_src_irn(edge);
1735 int p = get_edge_src_pos(edge);
1736 block_info_t *succ_info = get_block_info(succ);
1738 if (succ_info->processed) {
1739 add_phi_permutations(succ, p);
1744 typedef struct block_costs_t block_costs_t;
1745 struct block_costs_t {
1746 float costs; /**< costs of the block */
1747 int dfs_num; /**< depth first search number (to detect backedges) */
1750 static int cmp_block_costs(const void *d1, const void *d2)
1752 const ir_node * const *block1 = d1;
1753 const ir_node * const *block2 = d2;
1754 const block_costs_t *info1 = get_irn_link(*block1);
1755 const block_costs_t *info2 = get_irn_link(*block2);
1756 return QSORT_CMP(info2->costs, info1->costs);
1759 static void determine_block_order(void)
1762 ir_node **blocklist = be_get_cfgpostorder(irg);
1763 int n_blocks = ARR_LEN(blocklist);
1765 pdeq *worklist = new_pdeq();
1766 ir_node **order = XMALLOCN(ir_node*, n_blocks);
1769 /* clear block links... */
1770 for (i = 0; i < n_blocks; ++i) {
1771 ir_node *block = blocklist[i];
1772 set_irn_link(block, NULL);
1775 /* walk blocks in reverse postorder, the costs for each block are the
1776 * sum of the costs of its predecessors (excluding the costs on backedges
1777 * which we can't determine) */
1778 for (i = n_blocks-1; i >= 0; --i) {
1779 block_costs_t *cost_info;
1780 ir_node *block = blocklist[i];
1782 float execfreq = (float)get_block_execfreq(execfreqs, block);
1783 float costs = execfreq;
1784 int n_cfgpreds = get_Block_n_cfgpreds(block);
1786 for (p = 0; p < n_cfgpreds; ++p) {
1787 ir_node *pred_block = get_Block_cfgpred_block(block, p);
1788 block_costs_t *pred_costs = get_irn_link(pred_block);
1789 /* we don't have any info for backedges */
1790 if (pred_costs == NULL)
1792 costs += pred_costs->costs;
1795 cost_info = OALLOCZ(&obst, block_costs_t);
1796 cost_info->costs = costs;
1797 cost_info->dfs_num = dfs_num++;
1798 set_irn_link(block, cost_info);
1801 /* sort array by block costs */
1802 qsort(blocklist, n_blocks, sizeof(blocklist[0]), cmp_block_costs);
1804 ir_reserve_resources(irg, IR_RESOURCE_BLOCK_VISITED);
1805 inc_irg_block_visited(irg);
1807 for (i = 0; i < n_blocks; ++i) {
1808 ir_node *block = blocklist[i];
1809 if (Block_block_visited(block))
1812 /* continually add predecessors with highest costs to worklist
1813 * (without using backedges) */
1815 block_costs_t *info = get_irn_link(block);
1816 ir_node *best_pred = NULL;
1817 float best_costs = -1;
1818 int n_cfgpred = get_Block_n_cfgpreds(block);
1821 pdeq_putr(worklist, block);
1822 mark_Block_block_visited(block);
1823 for (i = 0; i < n_cfgpred; ++i) {
1824 ir_node *pred_block = get_Block_cfgpred_block(block, i);
1825 block_costs_t *pred_info = get_irn_link(pred_block);
1827 /* ignore backedges */
1828 if (pred_info->dfs_num > info->dfs_num)
1831 if (info->costs > best_costs) {
1832 best_costs = info->costs;
1833 best_pred = pred_block;
1837 } while (block != NULL && !Block_block_visited(block));
1839 /* now put all nodes in the worklist in our final order */
1840 while (!pdeq_empty(worklist)) {
1841 ir_node *pblock = pdeq_getr(worklist);
1842 assert(order_p < n_blocks);
1843 order[order_p++] = pblock;
1846 assert(order_p == n_blocks);
1849 ir_free_resources(irg, IR_RESOURCE_BLOCK_VISITED);
1851 DEL_ARR_F(blocklist);
1853 obstack_free(&obst, NULL);
1854 obstack_init(&obst);
1856 block_order = order;
1857 n_block_order = n_blocks;
1861 * Run the register allocator for the current register class.
1863 static void be_pref_alloc_cls(void)
1867 lv = be_assure_liveness(irg);
1868 be_liveness_assure_sets(lv);
1870 ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
1872 DB((dbg, LEVEL_2, "=== Allocating registers of %s ===\n", cls->name));
1874 be_clear_links(irg);
1876 irg_block_walk_graph(irg, NULL, analyze_block, NULL);
1877 if (create_congruence_classes)
1878 combine_congruence_classes();
1880 for (i = 0; i < n_block_order; ++i) {
1881 ir_node *block = block_order[i];
1882 allocate_coalesce_block(block, NULL);
1885 ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
1888 static void dump(int mask, ir_graph *irg, const char *suffix)
1890 if (be_get_irg_options(irg)->dump_flags & mask)
1891 dump_ir_graph(irg, suffix);
1895 * Run the spiller on the current graph.
1897 static void spill(void)
1899 /* make sure all nodes show their real register pressure */
1900 be_timer_push(T_RA_CONSTR);
1901 be_pre_spill_prepare_constr(irg, cls);
1902 be_timer_pop(T_RA_CONSTR);
1904 dump(DUMP_RA, irg, "-spillprepare");
1907 be_timer_push(T_RA_SPILL);
1908 be_do_spill(irg, cls);
1909 be_timer_pop(T_RA_SPILL);
1911 be_timer_push(T_RA_SPILL_APPLY);
1912 check_for_memory_operands(irg);
1913 be_timer_pop(T_RA_SPILL_APPLY);
1915 dump(DUMP_RA, irg, "-spill");
1919 * The pref register allocator for a whole procedure.
1921 static void be_pref_alloc(ir_graph *new_irg)
1923 const arch_env_t *arch_env = be_get_irg_arch_env(new_irg);
1924 int n_cls = arch_env_get_n_reg_class(arch_env);
1927 obstack_init(&obst);
1930 execfreqs = be_get_irg_exec_freq(irg);
1932 /* determine a good coloring order */
1933 determine_block_order();
1935 for (c = 0; c < n_cls; ++c) {
1936 cls = arch_env_get_reg_class(arch_env, c);
1937 default_cls_req = NULL;
1938 if (arch_register_class_flags(cls) & arch_register_class_flag_manual_ra)
1941 stat_ev_ctx_push_str("regcls", cls->name);
1943 n_regs = arch_register_class_n_regs(cls);
1944 normal_regs = rbitset_malloc(n_regs);
1945 be_abi_set_non_ignore_regs(be_get_irg_abi(irg), cls, normal_regs);
1949 /* verify schedule and register pressure */
1950 be_timer_push(T_VERIFY);
1951 if (be_get_irg_options(irg)->verify_option == BE_VERIFY_WARN) {
1952 be_verify_schedule(irg);
1953 be_verify_register_pressure(irg, cls);
1954 } else if (be_get_irg_options(irg)->verify_option == BE_VERIFY_ASSERT) {
1955 assert(be_verify_schedule(irg) && "Schedule verification failed");
1956 assert(be_verify_register_pressure(irg, cls)
1957 && "Register pressure verification failed");
1959 be_timer_pop(T_VERIFY);
1961 be_timer_push(T_RA_COLOR);
1962 be_pref_alloc_cls();
1963 be_timer_pop(T_RA_COLOR);
1965 /* we most probably constructed new Phis so liveness info is invalid
1967 /* TODO: test liveness_introduce */
1968 be_liveness_invalidate(lv);
1971 stat_ev_ctx_pop("regcls");
1974 be_timer_push(T_RA_SPILL_APPLY);
1975 be_abi_fix_stack_nodes(irg);
1976 be_timer_pop(T_RA_SPILL_APPLY);
1978 be_timer_push(T_VERIFY);
1979 if (be_get_irg_options(irg)->verify_option == BE_VERIFY_WARN) {
1980 be_verify_register_allocation(irg);
1981 } else if (be_get_irg_options(irg)->verify_option == BE_VERIFY_ASSERT) {
1982 assert(be_verify_register_allocation(irg)
1983 && "Register allocation invalid");
1985 be_timer_pop(T_VERIFY);
1987 obstack_free(&obst, NULL);
1990 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_pref_alloc);
1991 void be_init_pref_alloc(void)
1993 static be_ra_t be_ra_pref = {
1996 lc_opt_entry_t *be_grp = lc_opt_get_grp(firm_opt_get_root(), "be");
1997 lc_opt_entry_t *prefalloc_group = lc_opt_get_grp(be_grp, "prefalloc");
1998 lc_opt_add_table(prefalloc_group, options);
2000 be_register_allocator("pref", &be_ra_pref);
2001 FIRM_DBG_REGISTER(dbg, "firm.be.prefalloc");