1 /* Graph coloring register allocator
2 Copyright (C) 2001, 2002 Free Software Foundation, Inc.
3 Contributed by Michael Matz <matz@suse.de>
4 and Daniel Berlin <dan@cgsoftware.com>.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under the
9 terms of the GNU General Public License as published by the Free Software
10 Foundation; either version 2, or (at your option) any later version.
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
14 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
17 You should have received a copy of the GNU General Public License along
18 with GCC; see the file COPYING. If not, write to the Free Software
19 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
27 #include "hard-reg-set.h"
28 #include "basic-block.h"
33 /* This file is part of the graph coloring register allocator.
34 It contains the graph colorizer. Given an interference graph
35 as set up in ra-build.c the toplevel function in this file
36 (ra_colorize_graph) colorizes the graph, leaving a list
37 of colored, coalesced and spilled nodes.
39 The algorithm used is a merge of George & Appels iterative coalescing
40 and optimistic coalescing, switchable at runtime. The current default
41 is "optimistic coalescing +", which is based on the normal Briggs/Cooper
42 framework. We can also use biased coloring. Most of the structure
43 here follows the different papers.
45 Additionally there is a custom step to locally improve the overall
46 spill cost of the colored graph (recolor_spills). */
48 static void push_list PARAMS ((struct dlist *, struct dlist **));
49 static void push_list_end PARAMS ((struct dlist *, struct dlist **));
50 static void free_dlist PARAMS ((struct dlist **));
51 static void put_web_at_end PARAMS ((struct web *, enum node_type));
52 static void put_move PARAMS ((struct move *, enum move_type));
53 static void build_worklists PARAMS ((struct df *));
54 static void enable_move PARAMS ((struct web *));
55 static void decrement_degree PARAMS ((struct web *, int));
56 static void simplify PARAMS ((void));
57 static void remove_move_1 PARAMS ((struct web *, struct move *));
58 static void remove_move PARAMS ((struct web *, struct move *));
59 static void add_worklist PARAMS ((struct web *));
60 static int ok PARAMS ((struct web *, struct web *));
61 static int conservative PARAMS ((struct web *, struct web *));
62 static inline unsigned int simplify_p PARAMS ((enum node_type));
63 static void combine PARAMS ((struct web *, struct web *));
64 static void coalesce PARAMS ((void));
65 static void freeze_moves PARAMS ((struct web *));
66 static void freeze PARAMS ((void));
67 static void select_spill PARAMS ((void));
68 static int color_usable_p PARAMS ((int, HARD_REG_SET, HARD_REG_SET,
70 int get_free_reg PARAMS ((HARD_REG_SET, HARD_REG_SET, enum machine_mode));
71 static int get_biased_reg PARAMS ((HARD_REG_SET, HARD_REG_SET, HARD_REG_SET,
72 HARD_REG_SET, enum machine_mode));
73 static int count_long_blocks PARAMS ((HARD_REG_SET, int));
74 static char * hardregset_to_string PARAMS ((HARD_REG_SET));
75 static void calculate_dont_begin PARAMS ((struct web *, HARD_REG_SET *));
76 static void colorize_one_web PARAMS ((struct web *, int));
77 static void assign_colors PARAMS ((void));
78 static void try_recolor_web PARAMS ((struct web *));
79 static void insert_coalesced_conflicts PARAMS ((void));
80 static int comp_webs_maxcost PARAMS ((const void *, const void *));
81 static void recolor_spills PARAMS ((void));
82 static void check_colors PARAMS ((void));
83 static void restore_conflicts_from_coalesce PARAMS ((struct web *));
84 static void break_coalesced_spills PARAMS ((void));
85 static void unalias_web PARAMS ((struct web *));
86 static void break_aliases_to_web PARAMS ((struct web *));
87 static void break_precolored_alias PARAMS ((struct web *));
88 static void init_web_pairs PARAMS ((void));
89 static void add_web_pair_cost PARAMS ((struct web *, struct web *,
90 unsigned HOST_WIDE_INT, unsigned int));
91 static int comp_web_pairs PARAMS ((const void *, const void *));
92 static void sort_and_combine_web_pairs PARAMS ((int));
93 static void aggressive_coalesce PARAMS ((void));
94 static void extended_coalesce_2 PARAMS ((void));
95 static void check_uncoalesced_moves PARAMS ((void));
97 static struct dlist *mv_worklist, *mv_coalesced, *mv_constrained;
98 static struct dlist *mv_frozen, *mv_active;
100 /* Push a node onto the front of the list. */
107 if (x->next || x->prev)
116 push_list_end (x, list)
120 if (x->prev || x->next)
127 while ((*list)->next)
128 list = &((*list)->next);
133 /* Remove a node from the list. */
136 remove_list (x, list)
140 struct dlist *y = x->prev;
148 x->next = x->prev = NULL;
151 /* Pop the front of the list. */
157 struct dlist *r = *list;
159 remove_list (r, list);
163 /* Free the given double linked list. */
172 /* The web WEB should get the given new TYPE. Put it onto the
174 Inline, because it's called with constant TYPE every time. */
191 push_list (web->dlink, &WEBS(type));
194 push_list (web->dlink, &WEBS(INITIAL));
198 push_list (web->dlink, &WEBS(type = SIMPLIFY_SPILL));
199 else if (web->add_hardregs)
200 push_list (web->dlink, &WEBS(type = SIMPLIFY_FAT));
202 push_list (web->dlink, &WEBS(SIMPLIFY));
210 /* After we are done with the whole pass of coloring/spilling,
211 we reset the lists of webs, in preparation of the next pass.
212 The spilled webs become free, colored webs go to the initial list,
213 coalesced webs become free or initial, according to what type of web
214 they are coalesced to. */
221 if (WEBS(SIMPLIFY) || WEBS(SIMPLIFY_SPILL) || WEBS(SIMPLIFY_FAT)
222 || WEBS(FREEZE) || WEBS(SPILL) || WEBS(SELECT))
225 while ((d = pop_list (&WEBS(COALESCED))) != NULL)
227 struct web *web = DLIST_WEB (d);
228 struct web *aweb = alias (web);
229 /* Note, how alias() becomes invalid through the two put_web()'s
230 below. It might set the type of a web to FREE (from COALESCED),
231 which itself is a target of aliasing (i.e. in the middle of
232 an alias chain). We can handle this by checking also for
233 type == FREE. Note nevertheless, that alias() is invalid
235 if (aweb->type == SPILLED || aweb->type == FREE)
238 put_web (web, INITIAL);
240 while ((d = pop_list (&WEBS(SPILLED))) != NULL)
241 put_web (DLIST_WEB (d), FREE);
242 while ((d = pop_list (&WEBS(COLORED))) != NULL)
243 put_web (DLIST_WEB (d), INITIAL);
245 /* All free webs have no conflicts anymore. */
246 for (d = WEBS(FREE); d; d = d->next)
248 struct web *web = DLIST_WEB (d);
249 BITMAP_XFREE (web->useless_conflicts);
250 web->useless_conflicts = NULL;
253 /* Sanity check, that we only have free, initial or precolored webs. */
254 for (i = 0; i < num_webs; i++)
256 struct web *web = ID2WEB (i);
257 if (web->type != INITIAL && web->type != FREE && web->type != PRECOLORED)
260 free_dlist (&mv_worklist);
261 free_dlist (&mv_coalesced);
262 free_dlist (&mv_constrained);
263 free_dlist (&mv_frozen);
264 free_dlist (&mv_active);
267 /* Similar to put_web(), but add the web to the end of the appropriate
268 list. Additionally TYPE may not be SIMPLIFY. */
271 put_web_at_end (web, type)
275 if (type == PRECOLORED)
277 else if (type == SIMPLIFY)
279 push_list_end (web->dlink, &WEBS(type));
283 /* Unlink WEB from the list it's currently on (which corresponds to
284 its current type). */
287 remove_web_from_list (web)
290 if (web->type == PRECOLORED)
291 remove_list (web->dlink, &WEBS(INITIAL));
293 remove_list (web->dlink, &WEBS(web->type));
296 /* Give MOVE the TYPE, and link it into the correct list. */
299 put_move (move, type)
306 push_list (move->dlink, &mv_worklist);
309 push_list (move->dlink, &mv_coalesced);
312 push_list (move->dlink, &mv_constrained);
315 push_list (move->dlink, &mv_frozen);
318 push_list (move->dlink, &mv_active);
326 /* Build the worklists we are going to process. */
330 struct df *df ATTRIBUTE_UNUSED;
332 struct dlist *d, *d_next;
333 struct move_list *ml;
335 /* If we are not the first pass, put all stackwebs (which are still
336 backed by a new pseudo, but conceptually can stand for a stackslot,
337 i.e. it doesn't really matter if they get a color or not), on
338 the SELECT stack first, those with lowest cost first. This way
339 they will be colored last, so do not contrain the coloring of the
340 normal webs. But still those with the highest count are colored
341 before, i.e. get a color more probable. The use of stackregs is
342 a pure optimization, and all would work, if we used real stackslots
346 unsigned int i, num, max_num;
347 struct web **order2web;
348 max_num = num_webs - num_subwebs;
349 order2web = (struct web **) xmalloc (max_num * sizeof (order2web[0]));
350 for (i = 0, num = 0; i < max_num; i++)
351 if (id2web[i]->regno >= max_normal_pseudo)
352 order2web[num++] = id2web[i];
355 qsort (order2web, num, sizeof (order2web[0]), comp_webs_maxcost);
356 for (i = num - 1;; i--)
358 struct web *web = order2web[i];
359 struct conflict_link *wl;
360 remove_list (web->dlink, &WEBS(INITIAL));
361 put_web (web, SELECT);
362 for (wl = web->conflict_list; wl; wl = wl->next)
364 struct web *pweb = wl->t;
365 pweb->num_conflicts -= 1 + web->add_hardregs;
374 /* For all remaining initial webs, classify them. */
375 for (d = WEBS(INITIAL); d; d = d_next)
377 struct web *web = DLIST_WEB (d);
379 if (web->type == PRECOLORED)
382 remove_list (d, &WEBS(INITIAL));
383 if (web->num_conflicts >= NUM_REGS (web))
384 put_web (web, SPILL);
386 put_web (web, FREEZE);
388 put_web (web, SIMPLIFY);
391 /* And put all moves on the worklist for iterated coalescing.
392 Note, that if iterated coalescing is off, then wl_moves doesn't
393 contain any moves. */
394 for (ml = wl_moves; ml; ml = ml->next)
397 struct move *m = ml->move;
398 d = (struct dlist *) ra_calloc (sizeof (struct dlist));
401 put_move (m, WORKLIST);
405 /* Enable the active moves, in which WEB takes part, to be processed. */
411 struct move_list *ml;
412 for (ml = web->moves; ml; ml = ml->next)
413 if (ml->move->type == ACTIVE)
415 remove_list (ml->move->dlink, &mv_active);
416 put_move (ml->move, WORKLIST);
420 /* Decrement the degree of node WEB by the amount DEC.
421 Possibly change the type of WEB, if the number of conflicts is
422 now smaller than its freedom. */
425 decrement_degree (web, dec)
429 int before = web->num_conflicts;
430 web->num_conflicts -= dec;
431 if (web->num_conflicts < NUM_REGS (web) && before >= NUM_REGS (web))
433 struct conflict_link *a;
435 for (a = web->conflict_list; a; a = a->next)
437 struct web *aweb = a->t;
438 if (aweb->type != SELECT && aweb->type != COALESCED)
441 if (web->type != FREEZE)
443 remove_web_from_list (web);
445 put_web (web, FREEZE);
447 put_web (web, SIMPLIFY);
452 /* Repeatedly simplify the nodes on the simplify worklists. */
459 struct conflict_link *wl;
462 /* We try hard to color all the webs resulting from spills first.
463 Without that on register starved machines (x86 e.g) with some live
464 DImode pseudos, -fPIC, and an asm requiring %edx, it might be, that
465 we do rounds over rounds, because the conflict graph says, we can
466 simplify those short webs, but later due to irregularities we can't
467 color those pseudos. So we have to spill them, which in later rounds
468 leads to other spills. */
469 d = pop_list (&WEBS(SIMPLIFY));
471 d = pop_list (&WEBS(SIMPLIFY_FAT));
473 d = pop_list (&WEBS(SIMPLIFY_SPILL));
477 ra_debug_msg (DUMP_PROCESS, " simplifying web %3d, conflicts = %d\n",
478 web->id, web->num_conflicts);
479 put_web (web, SELECT);
480 for (wl = web->conflict_list; wl; wl = wl->next)
482 struct web *pweb = wl->t;
483 if (pweb->type != SELECT && pweb->type != COALESCED)
485 decrement_degree (pweb, 1 + web->add_hardregs);
491 /* Helper function to remove a move from the movelist of the web. */
494 remove_move_1 (web, move)
498 struct move_list *ml = web->moves;
501 if (ml->move == move)
503 web->moves = ml->next;
506 for (; ml->next && ml->next->move != move; ml = ml->next) ;
509 ml->next = ml->next->next;
512 /* Remove a move from the movelist of the web. Actually this is just a
513 wrapper around remove_move_1(), making sure, the removed move really is
514 not in the list anymore. */
517 remove_move (web, move)
521 struct move_list *ml;
522 remove_move_1 (web, move);
523 for (ml = web->moves; ml; ml = ml->next)
524 if (ml->move == move)
528 /* Merge the moves for the two webs into the first web's movelist. */
535 struct move_list *ml, *ml_next;
537 seen = BITMAP_XMALLOC ();
538 for (ml = u->moves; ml; ml = ml->next)
539 bitmap_set_bit (seen, INSN_UID (ml->move->insn));
540 for (ml = v->moves; ml; ml = ml_next)
543 if (! bitmap_bit_p (seen, INSN_UID (ml->move->insn)))
553 /* Add a web to the simplify worklist, from the freeze worklist. */
559 if (web->type != PRECOLORED && !web->moves
560 && web->num_conflicts < NUM_REGS (web))
562 remove_list (web->dlink, &WEBS(FREEZE));
563 put_web (web, SIMPLIFY);
567 /* Precolored node coalescing heuristic. */
571 struct web *target, *source;
573 struct conflict_link *wl;
575 int color = source->color;
578 /* Normally one would think, the next test wouldn't be needed.
579 We try to coalesce S and T, and S has already a color, and we checked
580 when processing the insns, that both have the same mode. So naively
581 we could conclude, that of course that mode was valid for this color.
582 Hah. But there is sparc. Before reload there are copy insns
583 (e.g. the ones copying arguments to locals) which happily refer to
584 colors in invalid modes. We can't coalesce those things. */
585 if (! HARD_REGNO_MODE_OK (source->color, GET_MODE (target->orig_x)))
588 /* Sanity for funny modes. */
589 size = HARD_REGNO_NREGS (color, GET_MODE (target->orig_x));
593 /* We can't coalesce target with a precolored register which isn't in
596 if (TEST_HARD_REG_BIT (never_use_colors, color + i)
597 || !TEST_HARD_REG_BIT (target->usable_regs, color + i)
598 /* Before usually calling ok() at all, we already test, if the
599 candidates conflict in sup_igraph. But when wide webs are
600 coalesced to hardregs, we only test the hardweb coalesced into.
601 This is only the begin color. When actually coalescing both,
602 it will also take the following size colors, i.e. their webs.
603 We nowhere checked if the candidate possibly conflicts with
604 one of _those_, which is possible with partial conflicts,
605 so we simply do it here (this does one bit-test more than
606 necessary, the first color). Note, that if X is precolored
607 bit [X*num_webs + Y] can't be set (see add_conflict_edge()). */
608 || TEST_BIT (sup_igraph,
609 target->id * num_webs + hardreg2web[color + i]->id))
612 for (wl = target->conflict_list; wl; wl = wl->next)
614 struct web *pweb = wl->t;
615 if (pweb->type == SELECT || pweb->type == COALESCED)
618 /* Coalescing target (T) and source (S) is o.k, if for
619 all conflicts C of T it is true, that:
620 1) C will be colored, or
621 2) C is a hardreg (precolored), or
622 3) C already conflicts with S too, or
623 4) a web which contains C conflicts already with S.
624 XXX: we handle here only the special case of 4), that C is
625 a subreg, and the containing thing is the reg itself, i.e.
626 we dont handle the situation, were T conflicts with
627 (subreg:SI x 1), and S conflicts with (subreg:DI x 0), which
628 would be allowed also, as the S-conflict overlaps
630 So, we first test the whole web for any of these conditions, and
631 continue with the next C, if 1, 2 or 3 is true. */
632 if (pweb->num_conflicts < NUM_REGS (pweb)
633 || pweb->type == PRECOLORED
634 || TEST_BIT (igraph, igraph_index (source->id, pweb->id)) )
637 /* This is reached, if not one of 1, 2 or 3 was true. In the case C has
638 no subwebs, 4 can't be true either, so we can't coalesce S and T. */
643 /* The main webs do _not_ conflict, only some parts of both. This
644 means, that 4 is possibly true, so we need to check this too.
645 For this we go thru all sub conflicts between T and C, and see if
646 the target part of C already conflicts with S. When this is not
647 the case we disallow coalescing. */
648 struct sub_conflict *sl;
649 for (sl = wl->sub; sl; sl = sl->next)
651 if (!TEST_BIT (igraph, igraph_index (source->id, sl->t->id)))
659 /* Non-precolored node coalescing heuristic. */
662 conservative (target, source)
663 struct web *target, *source;
668 struct conflict_link *wl;
669 unsigned int num_regs = NUM_REGS (target); /* XXX */
671 /* k counts the resulting conflict weight, if target and source
672 would be merged, and all low-degree neighbors would be
674 k = 0 * MAX (target->add_hardregs, source->add_hardregs);
675 seen = BITMAP_XMALLOC ();
676 for (loop = 0; loop < 2; loop++)
677 for (wl = ((loop == 0) ? target : source)->conflict_list;
680 struct web *pweb = wl->t;
681 if (pweb->type != SELECT && pweb->type != COALESCED
682 && pweb->num_conflicts >= NUM_REGS (pweb)
683 && ! REGNO_REG_SET_P (seen, pweb->id))
685 SET_REGNO_REG_SET (seen, pweb->id);
686 k += 1 + pweb->add_hardregs;
696 /* If the web is coalesced, return it's alias. Otherwise, return what
703 while (web->type == COALESCED)
708 /* Returns nonzero, if the TYPE belongs to one of those representing
711 static inline unsigned int
715 return type == SIMPLIFY || type == SIMPLIFY_SPILL || type == SIMPLIFY_FAT;
718 /* Actually combine two webs, that can be coalesced. */
725 struct conflict_link *wl;
726 if (u == v || v->type == COALESCED)
728 if ((u->regno >= max_normal_pseudo) != (v->regno >= max_normal_pseudo))
730 remove_web_from_list (v);
731 put_web (v, COALESCED);
735 u->num_aliased += 1 + v->num_aliased;
736 if (flag_ra_merge_spill_costs && u->type != PRECOLORED)
737 u->spill_cost += v->spill_cost;
738 /*u->spill_cost = MAX (u->spill_cost, v->spill_cost);*/
740 /* combine add_hardregs's of U and V. */
742 for (wl = v->conflict_list; wl; wl = wl->next)
744 struct web *pweb = wl->t;
745 /* We don't strictly need to move conflicts between webs which are
746 already coalesced or selected, if we do iterated coalescing, or
747 better if we need not to be able to break aliases again.
748 I.e. normally we would use the condition
749 (pweb->type != SELECT && pweb->type != COALESCED).
750 But for now we simply merge all conflicts. It doesn't take that
755 int nregs = 1 + v->add_hardregs;
756 if (u->type == PRECOLORED)
757 nregs = HARD_REGNO_NREGS (u->color, GET_MODE (v->orig_x));
759 /* For precolored U's we need to make conflicts between V's
760 neighbors and as many hardregs from U as V needed if it gets
761 color U. For now we approximate this by V->add_hardregs, which
762 could be too much in multi-length classes. We should really
763 count how many hardregs are needed for V with color U. When U
764 isn't precolored this loop breaks out after one iteration. */
765 for (i = 0; i < nregs; i++)
767 if (u->type == PRECOLORED)
768 web = hardreg2web[i + u->color];
770 record_conflict (web, pweb);
773 struct sub_conflict *sl;
774 /* So, between V and PWEB there are sub_conflicts. We
775 need to relocate those conflicts to be between WEB (==
776 U when it wasn't precolored) and PWEB. In the case
777 only a part of V conflicted with (part of) PWEB we
778 nevertheless make the new conflict between the whole U
779 and the (part of) PWEB. Later we might try to find in
780 U the correct subpart corresponding (by size and
781 offset) to the part of V (sl->s) which was the source
783 for (sl = wl->sub; sl; sl = sl->next)
785 /* Beware: sl->s is no subweb of web (== U) but of V.
786 We try to search a corresponding subpart of U.
787 If we found none we let it conflict with the whole U.
788 Note that find_subweb() only looks for mode and
789 subreg_byte of the REG rtx but not for the pseudo
790 reg number (otherwise it would be guaranteed to
791 _not_ find any subpart). */
792 struct web *sweb = NULL;
793 if (SUBWEB_P (sl->s))
794 sweb = find_subweb (web, sl->s->orig_x);
797 record_conflict (sweb, sl->t);
800 if (u->type != PRECOLORED)
803 if (pweb->type != SELECT && pweb->type != COALESCED)
804 decrement_degree (pweb, 1 + v->add_hardregs);
808 /* Now merge the usable_regs together. */
809 /* XXX That merging might normally make it necessary to
810 adjust add_hardregs, which also means to adjust neighbors. This can
811 result in making some more webs trivially colorable, (or the opposite,
812 if this increases our add_hardregs). Because we intersect the
813 usable_regs it should only be possible to decrease add_hardregs. So a
814 conservative solution for now is to simply don't change it. */
816 AND_HARD_REG_SET (u->usable_regs, v->usable_regs);
817 u->regclass = reg_class_subunion[u->regclass][v->regclass];
818 /* Count number of possible hardregs. This might make U a spillweb,
819 but that could also happen, if U and V together had too many
821 u->num_freedom = hard_regs_count (u->usable_regs);
822 u->num_freedom -= u->add_hardregs;
823 /* The next would mean an invalid coalesced move (both webs have no
824 possible hardreg in common), so abort. */
828 if (u->num_conflicts >= NUM_REGS (u)
829 && (u->type == FREEZE || simplify_p (u->type)))
831 remove_web_from_list (u);
835 /* We want the most relaxed combination of spill_temp state.
836 I.e. if any was no spilltemp or a spilltemp2, the result is so too,
837 otherwise if any is short, the result is too. It remains, when both
838 are normal spilltemps. */
839 if (v->spill_temp == 0)
841 else if (v->spill_temp == 2 && u->spill_temp != 0)
843 else if (v->spill_temp == 3 && u->spill_temp == 1)
847 /* Attempt to coalesce the first thing on the move worklist.
848 This is used only for iterated coalescing. */
853 struct dlist *d = pop_list (&mv_worklist);
854 struct move *m = DLIST_MOVE (d);
855 struct web *source = alias (m->source_web);
856 struct web *target = alias (m->target_web);
858 if (target->type == PRECOLORED)
860 struct web *h = source;
864 if (source == target)
866 remove_move (source, m);
867 put_move (m, MV_COALESCED);
868 add_worklist (source);
870 else if (target->type == PRECOLORED
871 || TEST_BIT (sup_igraph, source->id * num_webs + target->id)
872 || TEST_BIT (sup_igraph, target->id * num_webs + source->id))
874 remove_move (source, m);
875 remove_move (target, m);
876 put_move (m, CONSTRAINED);
877 add_worklist (source);
878 add_worklist (target);
880 else if ((source->type == PRECOLORED && ok (target, source))
881 || (source->type != PRECOLORED
882 && conservative (target, source)))
884 remove_move (source, m);
885 remove_move (target, m);
886 put_move (m, MV_COALESCED);
887 combine (source, target);
888 add_worklist (source);
891 put_move (m, ACTIVE);
894 /* Freeze the moves associated with the web. Used for iterated coalescing. */
900 struct move_list *ml, *ml_next;
901 for (ml = web->moves; ml; ml = ml_next)
903 struct move *m = ml->move;
904 struct web *src, *dest;
906 if (m->type == ACTIVE)
907 remove_list (m->dlink, &mv_active);
909 remove_list (m->dlink, &mv_worklist);
910 put_move (m, FROZEN);
911 remove_move (web, m);
912 src = alias (m->source_web);
913 dest = alias (m->target_web);
914 src = (src == web) ? dest : src;
915 remove_move (src, m);
916 /* XXX GA use the original v, instead of alias(v) */
917 if (!src->moves && src->num_conflicts < NUM_REGS (src))
919 remove_list (src->dlink, &WEBS(FREEZE));
920 put_web (src, SIMPLIFY);
925 /* Freeze the first thing on the freeze worklist (only for iterated
931 struct dlist *d = pop_list (&WEBS(FREEZE));
932 put_web (DLIST_WEB (d), SIMPLIFY);
933 freeze_moves (DLIST_WEB (d));
936 /* The current spill heuristic. Returns a number for a WEB.
937 Webs with higher numbers are selected later. */
939 static unsigned HOST_WIDE_INT (*spill_heuristic) PARAMS ((struct web *));
941 static unsigned HOST_WIDE_INT default_spill_heuristic PARAMS ((struct web *));
943 /* Our default heuristic is similar to spill_cost / num_conflicts.
944 Just scaled for integer arithmetic, and it favors coalesced webs,
945 and webs which span more insns with deaths. */
947 static unsigned HOST_WIDE_INT
948 default_spill_heuristic (web)
951 unsigned HOST_WIDE_INT ret;
952 unsigned int divisor = 1;
953 /* Make coalesce targets cheaper to spill, because they will be broken
954 up again into smaller parts. */
955 if (flag_ra_break_aliases)
956 divisor += web->num_aliased;
957 divisor += web->num_conflicts;
958 ret = ((web->spill_cost << 8) + divisor - 1) / divisor;
959 /* It is better to spill webs that span more insns (deaths in our
960 case) than other webs with the otherwise same spill_cost. So make
961 them a little bit cheaper. Remember that spill_cost is unsigned. */
962 if (web->span_deaths < ret)
963 ret -= web->span_deaths;
967 /* Select the cheapest spill to be potentially spilled (we don't
968 *actually* spill until we need to). */
973 unsigned HOST_WIDE_INT best = (unsigned HOST_WIDE_INT) -1;
974 struct dlist *bestd = NULL;
975 unsigned HOST_WIDE_INT best2 = (unsigned HOST_WIDE_INT) -1;
976 struct dlist *bestd2 = NULL;
978 for (d = WEBS(SPILL); d; d = d->next)
980 struct web *w = DLIST_WEB (d);
981 unsigned HOST_WIDE_INT cost = spill_heuristic (w);
982 if ((!w->spill_temp) && cost < best)
987 /* Specially marked spill temps can be spilled. Also coalesce
988 targets can. Eventually they will be broken up later in the
989 colorizing process, so if we have nothing better take that. */
990 else if ((w->spill_temp == 2 || w->is_coalesced) && cost < best2)
1004 /* Note the potential spill. */
1005 DLIST_WEB (bestd)->was_spilled = 1;
1006 remove_list (bestd, &WEBS(SPILL));
1007 put_web (DLIST_WEB (bestd), SIMPLIFY);
1008 freeze_moves (DLIST_WEB (bestd));
1009 ra_debug_msg (DUMP_PROCESS, " potential spill web %3d, conflicts = %d\n",
1010 DLIST_WEB (bestd)->id, DLIST_WEB (bestd)->num_conflicts);
1013 /* Given a set of forbidden colors to begin at, and a set of still
1014 free colors, and MODE, returns nonzero of color C is still usable. */
1017 color_usable_p (c, dont_begin_colors, free_colors, mode)
1019 HARD_REG_SET dont_begin_colors, free_colors;
1020 enum machine_mode mode;
1022 if (!TEST_HARD_REG_BIT (dont_begin_colors, c)
1023 && TEST_HARD_REG_BIT (free_colors, c)
1024 && HARD_REGNO_MODE_OK (c, mode))
1027 size = HARD_REGNO_NREGS (c, mode);
1028 for (i = 1; i < size && TEST_HARD_REG_BIT (free_colors, c + i); i++);
1035 /* I don't want to clutter up the actual code with ifdef's. */
1036 #ifdef REG_ALLOC_ORDER
1037 #define INV_REG_ALLOC_ORDER(c) inv_reg_alloc_order[c]
1039 #define INV_REG_ALLOC_ORDER(c) c
1042 /* Searches in FREE_COLORS for a block of hardregs of the right length
1043 for MODE, which doesn't begin at a hardreg mentioned in DONT_BEGIN_COLORS.
1044 If it needs more than one hardreg it prefers blocks beginning
1045 at an even hardreg, and only gives an odd begin reg if no other
1046 block could be found. */
1049 get_free_reg (dont_begin_colors, free_colors, mode)
1050 HARD_REG_SET dont_begin_colors, free_colors;
1051 enum machine_mode mode;
1054 int last_resort_reg = -1;
1056 int pref_reg_order = INT_MAX;
1057 int last_resort_reg_order = INT_MAX;
1059 for (c = 0; c < FIRST_PSEUDO_REGISTER; c++)
1060 if (!TEST_HARD_REG_BIT (dont_begin_colors, c)
1061 && TEST_HARD_REG_BIT (free_colors, c)
1062 && HARD_REGNO_MODE_OK (c, mode))
1065 size = HARD_REGNO_NREGS (c, mode);
1066 for (i = 1; i < size && TEST_HARD_REG_BIT (free_colors, c + i); i++);
1074 if (size < 2 || (c & 1) == 0)
1076 if (INV_REG_ALLOC_ORDER (c) < pref_reg_order)
1079 pref_reg_order = INV_REG_ALLOC_ORDER (c);
1082 else if (INV_REG_ALLOC_ORDER (c) < last_resort_reg_order)
1084 last_resort_reg = c;
1085 last_resort_reg_order = INV_REG_ALLOC_ORDER (c);
1091 return pref_reg >= 0 ? pref_reg : last_resort_reg;
1094 /* Similar to get_free_reg(), but first search in colors provided
1095 by BIAS _and_ PREFER_COLORS, then in BIAS alone, then in PREFER_COLORS
1096 alone, and only then for any free color. If flag_ra_biased is zero
1097 only do the last two steps. */
1100 get_biased_reg (dont_begin_colors, bias, prefer_colors, free_colors, mode)
1101 HARD_REG_SET dont_begin_colors, bias, prefer_colors, free_colors;
1102 enum machine_mode mode;
1108 COPY_HARD_REG_SET (s, dont_begin_colors);
1109 IOR_COMPL_HARD_REG_SET (s, bias);
1110 IOR_COMPL_HARD_REG_SET (s, prefer_colors);
1111 c = get_free_reg (s, free_colors, mode);
1114 COPY_HARD_REG_SET (s, dont_begin_colors);
1115 IOR_COMPL_HARD_REG_SET (s, bias);
1116 c = get_free_reg (s, free_colors, mode);
1120 COPY_HARD_REG_SET (s, dont_begin_colors);
1121 IOR_COMPL_HARD_REG_SET (s, prefer_colors);
1122 c = get_free_reg (s, free_colors, mode);
1125 c = get_free_reg (dont_begin_colors, free_colors, mode);
1129 /* Counts the number of non-overlapping bitblocks of length LEN
1133 count_long_blocks (free_colors, len)
1134 HARD_REG_SET free_colors;
1139 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1141 if (!TEST_HARD_REG_BIT (free_colors, i))
1143 for (j = 1; j < len; j++)
1144 if (!TEST_HARD_REG_BIT (free_colors, i + j))
1146 /* Bits [i .. i+j-1] are free. */
1154 /* Given a hardreg set S, return a string representing it.
1155 Either as 0/1 string, or as hex value depending on the implementation
1156 of hardreg sets. Note that this string is statically allocated. */
1159 hardregset_to_string (s)
1162 static char string[/*FIRST_PSEUDO_REGISTER + 30*/1024];
1163 #if FIRST_PSEUDO_REGISTER <= HOST_BITS_PER_WIDE_INT
1164 sprintf (string, HOST_WIDE_INT_PRINT_HEX, s);
1168 c += sprintf (c, "{ ");
1169 for (i = 0;i < HARD_REG_SET_LONGS; i++)
1171 for (j = 0; j < HOST_BITS_PER_WIDE_INT; j++)
1172 c += sprintf (c, "%s", ( 1 << j) & s[i] ? "1" : "0");
1173 c += sprintf (c, "%s", i ? ", " : "");
1175 c += sprintf (c, " }");
1180 /* For WEB, look at its already colored neighbors, and calculate
1181 the set of hardregs which is not allowed as color for WEB. Place
1182 that set int *RESULT. Note that the set of forbidden begin colors
1183 is not the same as all colors taken up by neighbors. E.g. suppose
1184 two DImode webs, but only the lo-part from one conflicts with the
1185 hipart from the other, and suppose the other gets colors 2 and 3
1186 (it needs two SImode hardregs). Now the first can take also color
1187 1 or 2, although in those cases there's a partial overlap. Only
1188 3 can't be used as begin color. */
1191 calculate_dont_begin (web, result)
1193 HARD_REG_SET *result;
1195 struct conflict_link *wl;
1196 HARD_REG_SET dont_begin;
1197 /* The bits set in dont_begin correspond to the hardregs, at which
1198 WEB may not begin. This differs from the set of _all_ hardregs which
1199 are taken by WEB's conflicts in the presence of wide webs, where only
1200 some parts conflict with others. */
1201 CLEAR_HARD_REG_SET (dont_begin);
1202 for (wl = web->conflict_list; wl; wl = wl->next)
1205 struct web *ptarget = alias (wl->t);
1206 struct sub_conflict *sl = wl->sub;
1207 w = sl ? sl->t : wl->t;
1210 if (ptarget->type == COLORED || ptarget->type == PRECOLORED)
1212 struct web *source = (sl) ? sl->s : web;
1213 unsigned int tsize = HARD_REGNO_NREGS (ptarget->color,
1214 GET_MODE (w->orig_x));
1215 /* ssize is only a first guess for the size. */
1216 unsigned int ssize = HARD_REGNO_NREGS (ptarget->color, GET_MODE
1218 unsigned int tofs = 0;
1219 unsigned int sofs = 0;
1220 /* C1 and C2 can become negative, so unsigned
1225 && GET_MODE_SIZE (GET_MODE (w->orig_x)) >= UNITS_PER_WORD)
1226 tofs = (SUBREG_BYTE (w->orig_x) / UNITS_PER_WORD);
1227 if (SUBWEB_P (source)
1228 && GET_MODE_SIZE (GET_MODE (source->orig_x))
1230 sofs = (SUBREG_BYTE (source->orig_x) / UNITS_PER_WORD);
1231 c1 = ptarget->color + tofs - sofs - ssize + 1;
1232 c2 = ptarget->color + tofs + tsize - 1 - sofs;
1237 /* Because ssize was only guessed above, which influenced our
1238 begin color (c1), we need adjustment, if for that color
1239 another size would be needed. This is done by moving
1240 c1 to a place, where the last of sources hardregs does not
1241 overlap the first of targets colors. */
1243 + HARD_REGNO_NREGS (c1, GET_MODE (source->orig_x)) - 1
1244 < ptarget->color + tofs)
1246 while (c1 > 0 && c1 + sofs
1247 + HARD_REGNO_NREGS (c1, GET_MODE (source->orig_x)) - 1
1248 > ptarget->color + tofs)
1250 for (; c1 <= c2; c1++)
1251 SET_HARD_REG_BIT (dont_begin, c1);
1254 /* The next if() only gets true, if there was no wl->sub at all, in
1255 which case we are only making one go thru this loop with W being
1260 w = sl ? sl->t : NULL;
1263 COPY_HARD_REG_SET (*result, dont_begin);
1266 /* Try to assign a color to WEB. If HARD if nonzero, we try many
1267 tricks to get it one color, including respilling already colored
1270 We also trie very hard, to not constrain the uncolored non-spill
1271 neighbors, which need more hardregs than we. Consider a situation, 2
1272 hardregs free for us (0 and 1), and one of our neighbors needs 2
1273 hardregs, and only conflicts with us. There are 3 hardregs at all. Now
1274 a simple minded method might choose 1 as color for us. Then our neighbor
1275 has two free colors (0 and 2) as it should, but they are not consecutive,
1276 so coloring it later would fail. This leads to nasty problems on
1277 register starved machines, so we try to avoid this. */
1280 colorize_one_web (web, hard)
1284 struct conflict_link *wl;
1285 HARD_REG_SET colors, dont_begin;
1288 int neighbor_needs= 0;
1289 struct web *fat_neighbor = NULL;
1290 struct web *fats_parent = NULL;
1292 int long_blocks = 0;
1293 int best_long_blocks = -1;
1294 HARD_REG_SET fat_colors;
1297 if (web->regno >= max_normal_pseudo)
1300 /* First we want to know the colors at which we can't begin. */
1301 calculate_dont_begin (web, &dont_begin);
1302 CLEAR_HARD_REG_SET (bias);
1304 /* Now setup the set of colors used by our neighbors neighbors,
1305 and search the biggest noncolored neighbor. */
1306 neighbor_needs = web->add_hardregs + 1;
1307 for (wl = web->conflict_list; wl; wl = wl->next)
1310 struct web *ptarget = alias (wl->t);
1311 struct sub_conflict *sl = wl->sub;
1312 IOR_HARD_REG_SET (bias, ptarget->bias_colors);
1313 w = sl ? sl->t : wl->t;
1314 if (ptarget->type != COLORED && ptarget->type != PRECOLORED
1315 && !ptarget->was_spilled)
1318 if (find_web_for_subweb (w)->type != COALESCED
1319 && w->add_hardregs >= neighbor_needs)
1321 neighbor_needs = w->add_hardregs;
1323 fats_parent = ptarget;
1329 w = sl ? sl->t : NULL;
1333 ra_debug_msg (DUMP_COLORIZE, "colorize web %d [don't begin at %s]", web->id,
1334 hardregset_to_string (dont_begin));
1336 /* If there are some fat neighbors, remember their usable regs,
1337 and how many blocks are free in it for that neighbor. */
1340 COPY_HARD_REG_SET (fat_colors, fats_parent->usable_regs);
1341 long_blocks = count_long_blocks (fat_colors, neighbor_needs + 1);
1344 /* We break out, if we found a color which doesn't constrain
1345 neighbors, or if we can't find any colors. */
1348 HARD_REG_SET call_clobbered;
1350 /* Here we choose a hard-reg for the current web. For non spill
1351 temporaries we first search in the hardregs for it's prefered
1352 class, then, if we found nothing appropriate, in those of the
1353 alternate class. For spill temporaries we only search in
1354 usable_regs of this web (which is probably larger than that of
1355 the preferred or alternate class). All searches first try to
1356 find a non-call-clobbered hard-reg.
1357 XXX this should be more finegraned... First look into preferred
1358 non-callclobbered hardregs, then _if_ the web crosses calls, in
1359 alternate non-cc hardregs, and only _then_ also in preferred cc
1360 hardregs (and alternate ones). Currently we don't track the number
1361 of calls crossed for webs. We should. */
1362 if (web->use_my_regs)
1364 COPY_HARD_REG_SET (colors, web->usable_regs);
1365 AND_HARD_REG_SET (colors,
1366 usable_regs[reg_preferred_class (web->regno)]);
1369 COPY_HARD_REG_SET (colors,
1370 usable_regs[reg_preferred_class (web->regno)]);
1371 #ifdef CLASS_CANNOT_CHANGE_MODE
1372 if (web->mode_changed)
1373 AND_COMPL_HARD_REG_SET (colors, reg_class_contents[
1374 (int) CLASS_CANNOT_CHANGE_MODE]);
1376 COPY_HARD_REG_SET (call_clobbered, colors);
1377 AND_HARD_REG_SET (call_clobbered, call_used_reg_set);
1379 /* If this web got a color in the last pass, try to give it the
1380 same color again. This will to much better colorization
1381 down the line, as we spilled for a certain coloring last time. */
1384 c = web->old_color - 1;
1385 if (!color_usable_p (c, dont_begin, colors,
1386 PSEUDO_REGNO_MODE (web->regno)))
1392 c = get_biased_reg (dont_begin, bias, web->prefer_colors,
1393 call_clobbered, PSEUDO_REGNO_MODE (web->regno));
1395 c = get_biased_reg (dont_begin, bias, web->prefer_colors,
1396 colors, PSEUDO_REGNO_MODE (web->regno));
1400 if (web->use_my_regs)
1401 IOR_HARD_REG_SET (colors, web->usable_regs);
1403 IOR_HARD_REG_SET (colors, usable_regs
1404 [reg_alternate_class (web->regno)]);
1405 #ifdef CLASS_CANNOT_CHANGE_MODE
1406 if (web->mode_changed)
1407 AND_COMPL_HARD_REG_SET (colors, reg_class_contents[
1408 (int) CLASS_CANNOT_CHANGE_MODE]);
1410 COPY_HARD_REG_SET (call_clobbered, colors);
1411 AND_HARD_REG_SET (call_clobbered, call_used_reg_set);
1413 c = get_biased_reg (dont_begin, bias, web->prefer_colors,
1414 call_clobbered, PSEUDO_REGNO_MODE (web->regno));
1416 c = get_biased_reg (dont_begin, bias, web->prefer_colors,
1417 colors, PSEUDO_REGNO_MODE (web->regno));
1423 /* If one of the yet uncolored neighbors, which is not a potential
1424 spill needs a block of hardregs be sure, not to destroy such a block
1425 by coloring one reg in the middle. */
1430 HARD_REG_SET colors1;
1431 COPY_HARD_REG_SET (colors1, fat_colors);
1432 for (i = 0; i < 1 + web->add_hardregs; i++)
1433 CLEAR_HARD_REG_BIT (colors1, c + i);
1434 new_long = count_long_blocks (colors1, neighbor_needs + 1);
1435 /* If we changed the number of long blocks, and it's now smaller
1436 than needed, we try to avoid this color. */
1437 if (long_blocks != new_long && new_long < num_fat)
1439 if (new_long > best_long_blocks)
1441 best_long_blocks = new_long;
1444 SET_HARD_REG_BIT (dont_begin, c);
1445 ra_debug_msg (DUMP_COLORIZE, " avoid %d", c);
1448 /* We found a color which doesn't destroy a block. */
1451 /* If we havee no fat neighbors, the current color won't become
1452 "better", so we've found it. */
1456 ra_debug_msg (DUMP_COLORIZE, " --> got %d", c < 0 ? bestc : c);
1457 if (bestc >= 0 && c < 0 && !web->was_spilled)
1459 /* This is a non-potential-spill web, which got a color, which did
1460 destroy a hardreg block for one of it's neighbors. We color
1461 this web anyway and hope for the best for the neighbor, if we are
1463 if (1 || web->spill_temp)
1465 ra_debug_msg (DUMP_COLORIZE, " [constrains neighbors]");
1467 ra_debug_msg (DUMP_COLORIZE, "\n");
1471 /* Guard against a simplified node being spilled. */
1472 /* Don't abort. This can happen, when e.g. enough registers
1473 are available in colors, but they are not consecutive. This is a
1474 very serious issue if this web is a short live one, because
1475 even if we spill this one here, the situation won't become better
1476 in the next iteration. It probably will have the same conflicts,
1477 those will have the same colors, and we would come here again, for
1478 all parts, in which this one gets splitted by the spill. This
1479 can result in endless iteration spilling the same register again and
1480 again. That's why we try to find a neighbor, which spans more
1481 instructions that ourself, and got a color, and try to spill _that_.
1483 if (DLIST_WEB (d)->was_spilled < 0)
1485 if (hard && (!web->was_spilled || web->spill_temp))
1488 struct web *try = NULL;
1489 struct web *candidates[8];
1491 ra_debug_msg (DUMP_COLORIZE, " *** %d spilled, although %s ***\n",
1492 web->id, web->spill_temp ? "spilltemp" : "non-spill");
1493 /* We make multiple passes over our conflicts, first trying to
1494 spill those webs, which only got a color by chance, but
1495 were potential spill ones, and if that isn't enough, in a second
1496 pass also to spill normal colored webs. If we still didn't find
1497 a candidate, but we are a spill-temp, we make a third pass
1498 and include also webs, which were targets for coalescing, and
1500 memset (candidates, 0, sizeof candidates);
1501 #define set_cand(i, w) \
1503 if (!candidates[(i)] \
1504 || (candidates[(i)]->spill_cost < (w)->spill_cost)) \
1505 candidates[(i)] = (w); \
1507 for (wl = web->conflict_list; wl; wl = wl->next)
1509 struct web *w = wl->t;
1510 struct web *aw = alias (w);
1511 /* If we are a spill-temp, we also look at webs coalesced
1512 to precolored ones. Otherwise we only look at webs which
1513 themself were colored, or coalesced to one. */
1514 if (aw->type == PRECOLORED && w != aw && web->spill_temp
1515 && flag_ra_optimistic_coalescing)
1519 else if (web->spill_temp == 2
1520 && w->spill_temp == 2
1521 && w->spill_cost < web->spill_cost)
1523 else if (web->spill_temp != 2
1524 && (w->spill_temp == 2
1525 || w->spill_cost < web->spill_cost))
1529 if (aw->type != COLORED)
1531 if (w->type == COLORED && !w->spill_temp && !w->is_coalesced
1534 if (w->spill_cost < web->spill_cost)
1536 else if (web->spill_temp)
1539 if (w->type == COLORED && !w->spill_temp && !w->is_coalesced
1542 if (w->spill_cost < web->spill_cost)
1544 else if (web->spill_temp && web->spill_temp != 2)
1547 if (web->spill_temp)
1549 if (w->type == COLORED && w->spill_temp == 2
1551 && (w->spill_cost < web->spill_cost
1552 || web->spill_temp != 2))
1554 if (!aw->spill_temp)
1556 if (aw->spill_temp == 2
1557 && (aw->spill_cost < web->spill_cost
1558 || web->spill_temp != 2))
1560 /* For boehm-gc/misc.c. If we are a difficult spilltemp,
1561 also coalesced neighbors are a chance, _even_ if they
1562 too are spilltemps. At least their coalscing can be
1563 broken up, which may be reset usable_regs, and makes
1564 it easier colorable. */
1565 if (web->spill_temp != 2 && aw->is_coalesced
1566 && flag_ra_optimistic_coalescing)
1570 for (loop = 0; try == NULL && loop < 8; loop++)
1571 if (candidates[loop])
1572 try = candidates[loop];
1576 int old_c = try->color;
1577 if (try->type == COALESCED)
1579 if (alias (try)->type != PRECOLORED)
1581 ra_debug_msg (DUMP_COLORIZE, " breaking alias %d -> %d\n",
1582 try->id, alias (try)->id);
1583 break_precolored_alias (try);
1584 colorize_one_web (web, hard);
1588 remove_list (try->dlink, &WEBS(COLORED));
1589 put_web (try, SPILLED);
1590 /* Now try to colorize us again. Can recursively make other
1591 webs also spill, until there are no more unspilled
1593 ra_debug_msg (DUMP_COLORIZE, " trying to spill %d\n", try->id);
1594 colorize_one_web (web, hard);
1595 if (web->type != COLORED)
1597 /* We tried recursively to spill all already colored
1598 neighbors, but we are still uncolorable. So it made
1599 no sense to spill those neighbors. Recolor them. */
1600 remove_list (try->dlink, &WEBS(SPILLED));
1601 put_web (try, COLORED);
1603 ra_debug_msg (DUMP_COLORIZE,
1604 " spilling %d was useless\n", try->id);
1608 ra_debug_msg (DUMP_COLORIZE,
1609 " to spill %d was a good idea\n",
1611 remove_list (try->dlink, &WEBS(SPILLED));
1612 if (try->was_spilled)
1613 colorize_one_web (try, 0);
1615 colorize_one_web (try, hard - 1);
1620 /* No more chances to get a color, so give up hope and
1622 put_web (web, SPILLED);
1625 put_web (web, SPILLED);
1629 put_web (web, COLORED);
1633 int nregs = HARD_REGNO_NREGS (c, GET_MODE (web->orig_x));
1634 for (wl = web->conflict_list; wl; wl = wl->next)
1636 struct web *ptarget = alias (wl->t);
1638 for (i = 0; i < nregs; i++)
1639 SET_HARD_REG_BIT (ptarget->bias_colors, c + i);
1643 if (web->regno >= max_normal_pseudo && web->type == SPILLED)
1645 web->color = an_unusable_color;
1646 remove_list (web->dlink, &WEBS(SPILLED));
1647 put_web (web, COLORED);
1649 if (web->type == SPILLED && flag_ra_optimistic_coalescing
1650 && web->is_coalesced)
1652 ra_debug_msg (DUMP_COLORIZE, "breaking aliases to web %d:", web->id);
1653 restore_conflicts_from_coalesce (web);
1654 break_aliases_to_web (web);
1655 insert_coalesced_conflicts ();
1656 ra_debug_msg (DUMP_COLORIZE, "\n");
1657 remove_list (web->dlink, &WEBS(SPILLED));
1658 put_web (web, SELECT);
1663 /* Assign the colors to all nodes on the select stack. And update the
1664 colors of coalesced webs. */
1671 while (WEBS(SELECT))
1674 d = pop_list (&WEBS(SELECT));
1675 web = DLIST_WEB (d);
1676 colorize_one_web (DLIST_WEB (d), 1);
1679 for (d = WEBS(COALESCED); d; d = d->next)
1681 struct web *a = alias (DLIST_WEB (d));
1682 DLIST_WEB (d)->color = a->color;
1686 /* WEB is a spilled web. Look if we can improve the cost of the graph,
1687 by coloring WEB, even if we then need to spill some of it's neighbors.
1688 For this we calculate the cost for each color C, that results when we
1689 _would_ give WEB color C (i.e. the cost of the then spilled neighbors).
1690 If the lowest cost among them is smaller than the spillcost of WEB, we
1691 do that recoloring, and instead spill the neighbors.
1693 This can sometime help, when due to irregularities in register file,
1694 and due to multi word pseudos, the colorization is suboptimal. But
1695 be aware, that currently this pass is quite slow. */
1698 try_recolor_web (web)
1701 struct conflict_link *wl;
1702 unsigned HOST_WIDE_INT *cost_neighbors;
1703 unsigned int *min_color;
1705 HARD_REG_SET precolored_neighbors, spill_temps;
1706 HARD_REG_SET possible_begin, wide_seen;
1707 cost_neighbors = (unsigned HOST_WIDE_INT *)
1708 xcalloc (FIRST_PSEUDO_REGISTER, sizeof (cost_neighbors[0]));
1709 /* For each hard-regs count the number of preceding hardregs, which
1710 would overlap this color, if used in WEB's mode. */
1711 min_color = (unsigned int *) xcalloc (FIRST_PSEUDO_REGISTER, sizeof (int));
1712 CLEAR_HARD_REG_SET (possible_begin);
1713 for (c = 0; c < FIRST_PSEUDO_REGISTER; c++)
1716 if (!HARD_REGNO_MODE_OK (c, GET_MODE (web->orig_x)))
1718 nregs = HARD_REGNO_NREGS (c, GET_MODE (web->orig_x));
1719 for (i = 0; i < nregs; i++)
1720 if (!TEST_HARD_REG_BIT (web->usable_regs, c + i))
1722 if (i < nregs || nregs == 0)
1724 SET_HARD_REG_BIT (possible_begin, c);
1726 if (!min_color[c + nregs])
1727 min_color[c + nregs] = 1 + c;
1729 CLEAR_HARD_REG_SET (precolored_neighbors);
1730 CLEAR_HARD_REG_SET (spill_temps);
1731 CLEAR_HARD_REG_SET (wide_seen);
1732 for (wl = web->conflict_list; wl; wl = wl->next)
1734 HARD_REG_SET dont_begin;
1735 struct web *web2 = alias (wl->t);
1736 struct conflict_link *nn;
1739 if (wl->t->type == COALESCED || web2->type != COLORED)
1741 if (web2->type == PRECOLORED)
1743 c1 = min_color[web2->color];
1744 c1 = (c1 == 0) ? web2->color : (c1 - 1);
1746 for (; c1 <= c2; c1++)
1747 SET_HARD_REG_BIT (precolored_neighbors, c1);
1751 /* Mark colors for which some wide webs are involved. For
1752 those the independent sets are not simply one-node graphs, so
1753 they can't be recolored independ from their neighborhood. This
1754 means, that our cost calculation can be incorrect (assuming it
1755 can avoid spilling a web because it thinks some colors are available,
1756 although it's neighbors which itself need recoloring might take
1757 away exactly those colors). */
1758 if (web2->add_hardregs)
1760 for (nn = web2->conflict_list; nn && !wide_p; nn = nn->next)
1761 if (alias (nn->t)->add_hardregs)
1763 calculate_dont_begin (web2, &dont_begin);
1764 c1 = min_color[web2->color];
1765 /* Note that min_color[] contains 1-based values (zero means
1767 c1 = c1 == 0 ? web2->color : (c1 - 1);
1768 c2 = web2->color + HARD_REGNO_NREGS (web2->color, GET_MODE
1769 (web2->orig_x)) - 1;
1770 for (; c1 <= c2; c1++)
1771 if (TEST_HARD_REG_BIT (possible_begin, c1))
1774 HARD_REG_SET colors;
1775 nregs = HARD_REGNO_NREGS (c1, GET_MODE (web->orig_x));
1776 COPY_HARD_REG_SET (colors, web2->usable_regs);
1778 CLEAR_HARD_REG_BIT (colors, c1 + nregs);
1780 SET_HARD_REG_BIT (wide_seen, c1);
1781 if (get_free_reg (dont_begin, colors,
1782 GET_MODE (web2->orig_x)) < 0)
1784 if (web2->spill_temp)
1785 SET_HARD_REG_BIT (spill_temps, c1);
1787 cost_neighbors[c1] += web2->spill_cost;
1792 for (c = 0; c < FIRST_PSEUDO_REGISTER; c++)
1793 if (TEST_HARD_REG_BIT (possible_begin, c)
1794 && !TEST_HARD_REG_BIT (precolored_neighbors, c)
1795 && !TEST_HARD_REG_BIT (spill_temps, c)
1797 || cost_neighbors[c] < cost_neighbors[newcol]))
1799 if (newcol >= 0 && cost_neighbors[newcol] < web->spill_cost)
1801 int nregs = HARD_REGNO_NREGS (newcol, GET_MODE (web->orig_x));
1802 unsigned HOST_WIDE_INT cost = 0;
1804 struct conflict_link *wl_next;
1805 ra_debug_msg (DUMP_COLORIZE, "try to set web %d to color %d\n", web->id,
1807 remove_list (web->dlink, &WEBS(SPILLED));
1808 put_web (web, COLORED);
1809 web->color = newcol;
1810 old_colors = (int *) xcalloc (num_webs, sizeof (int));
1811 for (wl = web->conflict_list; wl; wl = wl_next)
1813 struct web *web2 = alias (wl->t);
1814 /* If web2 is a coalesce-target, and will become spilled
1815 below in colorize_one_web(), and the current conflict wl
1816 between web and web2 was only the result of that coalescing
1817 this conflict will be deleted, making wl invalid. So save
1818 the next conflict right now. Note that if web2 has indeed
1819 such state, then wl->next can not be deleted in this
1822 if (web2->type == COLORED)
1824 int nregs2 = HARD_REGNO_NREGS (web2->color, GET_MODE
1826 if (web->color >= web2->color + nregs2
1827 || web2->color >= web->color + nregs)
1829 old_colors[web2->id] = web2->color + 1;
1831 remove_list (web2->dlink, &WEBS(COLORED));
1832 web2->type = SELECT;
1833 /* Allow webs to be spilled. */
1834 if (web2->spill_temp == 0 || web2->spill_temp == 2)
1835 web2->was_spilled = 1;
1836 colorize_one_web (web2, 1);
1837 if (web2->type == SPILLED)
1838 cost += web2->spill_cost;
1841 /* The actual cost may be smaller than the guessed one, because
1842 partial conflicts could result in some conflicting webs getting
1843 a color, where we assumed it must be spilled. See the comment
1844 above what happens, when wide webs are involved, and why in that
1845 case there might actually be some webs spilled although thought to
1847 if (cost > cost_neighbors[newcol]
1848 && nregs == 1 && !TEST_HARD_REG_BIT (wide_seen, newcol))
1850 /* But if the new spill-cost is higher than our own, then really loose.
1851 Respill us and recolor neighbors as before. */
1852 if (cost > web->spill_cost)
1854 ra_debug_msg (DUMP_COLORIZE,
1855 "reset coloring of web %d, too expensive\n", web->id);
1856 remove_list (web->dlink, &WEBS(COLORED));
1858 put_web (web, SPILLED);
1859 for (wl = web->conflict_list; wl; wl = wl->next)
1861 struct web *web2 = alias (wl->t);
1862 if (old_colors[web2->id])
1864 if (web2->type == SPILLED)
1866 remove_list (web2->dlink, &WEBS(SPILLED));
1867 web2->color = old_colors[web2->id] - 1;
1868 put_web (web2, COLORED);
1870 else if (web2->type == COLORED)
1871 web2->color = old_colors[web2->id] - 1;
1872 else if (web2->type == SELECT)
1873 /* This means, that WEB2 once was a part of a coalesced
1874 web, which got spilled in the above colorize_one_web()
1875 call, and whose parts then got splitted and put back
1876 onto the SELECT stack. As the cause for that splitting
1877 (the coloring of WEB) was worthless, we should again
1878 coalesce the parts, as they were before. For now we
1879 simply leave them SELECTed, for our caller to take
1890 free (cost_neighbors);
1893 /* This ensures that all conflicts of coalesced webs are seen from
1894 the webs coalesced into. combine() only adds the conflicts which
1895 at the time of combining were not already SELECTed or COALESCED
1896 to not destroy num_conflicts. Here we add all remaining conflicts
1897 and thereby destroy num_conflicts. This should be used when num_conflicts
1898 isn't used anymore, e.g. on a completely colored graph. */
1901 insert_coalesced_conflicts ()
1904 for (d = WEBS(COALESCED); 0 && d; d = d->next)
1906 struct web *web = DLIST_WEB (d);
1907 struct web *aweb = alias (web);
1908 struct conflict_link *wl;
1909 for (wl = web->conflict_list; wl; wl = wl->next)
1911 struct web *tweb = aweb;
1913 int nregs = 1 + web->add_hardregs;
1914 if (aweb->type == PRECOLORED)
1915 nregs = HARD_REGNO_NREGS (aweb->color, GET_MODE (web->orig_x));
1916 for (i = 0; i < nregs; i++)
1918 if (aweb->type == PRECOLORED)
1919 tweb = hardreg2web[i + aweb->color];
1920 /* There might be some conflict edges laying around
1921 where the usable_regs don't intersect. This can happen
1922 when first some webs were coalesced and conflicts
1923 propagated, then some combining narrowed usable_regs and
1924 further coalescing ignored those conflicts. Now there are
1925 some edges to COALESCED webs but not to it's alias.
1926 So abort only when they really should conflict. */
1927 if ((!(tweb->type == PRECOLORED
1928 || TEST_BIT (sup_igraph, tweb->id * num_webs + wl->t->id))
1929 || !(wl->t->type == PRECOLORED
1930 || TEST_BIT (sup_igraph,
1931 wl->t->id * num_webs + tweb->id)))
1932 && hard_regs_intersect_p (&tweb->usable_regs,
1933 &wl->t->usable_regs))
1935 /*if (wl->sub == NULL)
1936 record_conflict (tweb, wl->t);
1939 struct sub_conflict *sl;
1940 for (sl = wl->sub; sl; sl = sl->next)
1941 record_conflict (tweb, sl->t);
1943 if (aweb->type != PRECOLORED)
1950 /* A function suitable to pass to qsort(). Compare the spill costs
1951 of webs W1 and W2. When used by qsort, this would order webs with
1952 largest cost first. */
1955 comp_webs_maxcost (w1, w2)
1956 const void *w1, *w2;
1958 struct web *web1 = *(struct web **)w1;
1959 struct web *web2 = *(struct web **)w2;
1960 if (web1->spill_cost > web2->spill_cost)
1962 else if (web1->spill_cost < web2->spill_cost)
1968 /* This tries to recolor all spilled webs. See try_recolor_web()
1969 how this is done. This just calls it for each spilled web. */
1974 unsigned int i, num;
1975 struct web **order2web;
1976 num = num_webs - num_subwebs;
1977 order2web = (struct web **) xmalloc (num * sizeof (order2web[0]));
1978 for (i = 0; i < num; i++)
1980 order2web[i] = id2web[i];
1981 /* If we aren't breaking aliases, combine() wasn't merging the
1982 spill_costs. So do that here to have sane measures. */
1983 if (!flag_ra_merge_spill_costs && id2web[i]->type == COALESCED)
1984 alias (id2web[i])->spill_cost += id2web[i]->spill_cost;
1986 qsort (order2web, num, sizeof (order2web[0]), comp_webs_maxcost);
1987 insert_coalesced_conflicts ();
1988 dump_graph_cost (DUMP_COSTS, "before spill-recolor");
1989 for (i = 0; i < num; i++)
1991 struct web *web = order2web[i];
1992 if (web->type == SPILLED)
1993 try_recolor_web (web);
1995 /* It might have been decided in try_recolor_web() (in colorize_one_web())
1996 that a coalesced web should be spilled, so it was put on the
1997 select stack. Those webs need recoloring again, and all remaining
1998 coalesced webs might need their color updated, so simply call
1999 assign_colors() again. */
2004 /* This checks the current color assignment for obvious errors,
2005 like two conflicting webs overlapping in colors, or the used colors
2006 not being in usable regs. */
2012 for (i = 0; i < num_webs - num_subwebs; i++)
2014 struct web *web = id2web[i];
2015 struct web *aweb = alias (web);
2016 struct conflict_link *wl;
2018 if (aweb->type == SPILLED || web->regno >= max_normal_pseudo)
2020 else if (aweb->type == COLORED)
2021 nregs = HARD_REGNO_NREGS (aweb->color, GET_MODE (web->orig_x));
2022 else if (aweb->type == PRECOLORED)
2026 /* The color must be valid for the original usable_regs. */
2027 for (c = 0; c < nregs; c++)
2028 if (!TEST_HARD_REG_BIT (web->usable_regs, aweb->color + c))
2030 /* Search the original (pre-coalesce) conflict list. In the current
2031 one some inprecise conflicts may be noted (due to combine() or
2032 insert_coalesced_conflicts() relocating partial conflicts) making
2033 it look like some wide webs are in conflict and having the same
2035 wl = (web->have_orig_conflicts ? web->orig_conflict_list
2036 : web->conflict_list);
2037 for (; wl; wl = wl->next)
2038 if (wl->t->regno >= max_normal_pseudo)
2042 struct web *web2 = alias (wl->t);
2044 if (web2->type == COLORED)
2045 nregs2 = HARD_REGNO_NREGS (web2->color, GET_MODE (web2->orig_x));
2046 else if (web2->type == PRECOLORED)
2050 if (aweb->color >= web2->color + nregs2
2051 || web2->color >= aweb->color + nregs)
2057 struct sub_conflict *sl;
2058 int scol = aweb->color;
2059 int tcol = alias (wl->t)->color;
2060 if (alias (wl->t)->type == SPILLED)
2062 for (sl = wl->sub; sl; sl = sl->next)
2064 int ssize = HARD_REGNO_NREGS (scol, GET_MODE (sl->s->orig_x));
2065 int tsize = HARD_REGNO_NREGS (tcol, GET_MODE (sl->t->orig_x));
2066 int sofs = 0, tofs = 0;
2067 if (SUBWEB_P (sl->t)
2068 && GET_MODE_SIZE (GET_MODE (sl->t->orig_x)) >= UNITS_PER_WORD)
2069 tofs = (SUBREG_BYTE (sl->t->orig_x) / UNITS_PER_WORD);
2070 if (SUBWEB_P (sl->s)
2071 && GET_MODE_SIZE (GET_MODE (sl->s->orig_x))
2073 sofs = (SUBREG_BYTE (sl->s->orig_x) / UNITS_PER_WORD);
2074 if ((tcol + tofs >= scol + sofs + ssize)
2075 || (scol + sofs >= tcol + tofs + tsize))
2083 /* WEB was a coalesced web. Make it unaliased again, and put it
2084 back onto SELECT stack. */
2091 web->is_coalesced = 0;
2093 /* Well, initially everything was spilled, so it isn't incorrect,
2094 that also the individual parts can be spilled.
2095 XXX this isn't entirely correct, as we also relaxed the
2096 spill_temp flag in combine(), which might have made components
2097 spill, although they were a short or spilltemp web. */
2098 web->was_spilled = 1;
2099 remove_list (web->dlink, &WEBS(COALESCED));
2100 /* Spilltemps must be colored right now (i.e. as early as possible),
2101 other webs can be deferred to the end (the code building the
2102 stack assumed that in this stage only one web was colored). */
2103 if (web->spill_temp && web->spill_temp != 2)
2104 put_web (web, SELECT);
2106 put_web_at_end (web, SELECT);
2109 /* WEB is a _target_ for coalescing which got spilled.
2110 Break all aliases to WEB, and restore some of its member to the state
2111 they were before coalescing. Due to the suboptimal structure of
2112 the interference graph we need to go through all coalesced webs.
2113 Somewhen we'll change this to be more sane. */
2116 break_aliases_to_web (web)
2119 struct dlist *d, *d_next;
2120 if (web->type != SPILLED)
2122 for (d = WEBS(COALESCED); d; d = d_next)
2124 struct web *other = DLIST_WEB (d);
2126 /* Beware: Don't use alias() here. We really want to check only
2127 one level of aliasing, i.e. only break up webs directly
2128 aliased to WEB, not also those aliased through other webs. */
2129 if (other->alias == web)
2131 unalias_web (other);
2132 ra_debug_msg (DUMP_COLORIZE, " %d", other->id);
2135 web->spill_temp = web->orig_spill_temp;
2136 web->spill_cost = web->orig_spill_cost;
2137 /* Beware: The following possibly widens usable_regs again. While
2138 it was narrower there might have been some conflicts added which got
2139 ignored because of non-intersecting hardregsets. All those conflicts
2140 would now matter again. Fortunately we only add conflicts when
2141 coalescing, which is also the time of narrowing. And we remove all
2142 those added conflicts again now that we unalias this web.
2143 Therefore this is safe to do. */
2144 COPY_HARD_REG_SET (web->usable_regs, web->orig_usable_regs);
2145 web->is_coalesced = 0;
2146 web->num_aliased = 0;
2147 web->was_spilled = 1;
2148 /* Reset is_coalesced flag for webs which itself are target of coalescing.
2149 It was cleared above if it was coalesced to WEB. */
2150 for (d = WEBS(COALESCED); d; d = d->next)
2151 DLIST_WEB (d)->alias->is_coalesced = 1;
2154 /* WEB is a web coalesced into a precolored one. Break that alias,
2155 making WEB SELECTed again. Also restores the conflicts which resulted
2156 from initially coalescing both. */
2159 break_precolored_alias (web)
2162 struct web *pre = web->alias;
2163 struct conflict_link *wl;
2164 unsigned int c = pre->color;
2165 unsigned int nregs = HARD_REGNO_NREGS (c, GET_MODE (web->orig_x));
2166 if (pre->type != PRECOLORED)
2169 /* Now we need to look at each conflict X of WEB, if it conflicts
2170 with [PRE, PRE+nregs), and remove such conflicts, of X has not other
2171 conflicts, which are coalesced into those precolored webs. */
2172 for (wl = web->conflict_list; wl; wl = wl->next)
2174 struct web *x = wl->t;
2177 struct conflict_link *wl2;
2178 struct conflict_link **pcl;
2180 if (!x->have_orig_conflicts)
2182 /* First look at which colors can not go away, due to other coalesces
2184 CLEAR_HARD_REG_SET (regs);
2185 for (i = 0; i < nregs; i++)
2186 SET_HARD_REG_BIT (regs, c + i);
2187 for (wl2 = x->conflict_list; wl2; wl2 = wl2->next)
2188 if (wl2->t->type == COALESCED && alias (wl2->t)->type == PRECOLORED)
2189 CLEAR_HARD_REG_BIT (regs, alias (wl2->t)->color);
2190 /* Now also remove the colors of those conflicts which already
2191 were there before coalescing at all. */
2192 for (wl2 = x->orig_conflict_list; wl2; wl2 = wl2->next)
2193 if (wl2->t->type == PRECOLORED)
2194 CLEAR_HARD_REG_BIT (regs, wl2->t->color);
2195 /* The colors now still set are those for which WEB was the last
2196 cause, i.e. those which can be removed. */
2198 for (i = 0; i < nregs; i++)
2199 if (TEST_HARD_REG_BIT (regs, c + i))
2202 y = hardreg2web[c + i];
2203 RESET_BIT (sup_igraph, x->id * num_webs + y->id);
2204 RESET_BIT (sup_igraph, y->id * num_webs + x->id);
2205 RESET_BIT (igraph, igraph_index (x->id, y->id));
2206 for (sub = x->subreg_next; sub; sub = sub->subreg_next)
2207 RESET_BIT (igraph, igraph_index (sub->id, y->id));
2211 pcl = &(x->conflict_list);
2214 struct web *y = (*pcl)->t;
2215 if (y->type != PRECOLORED || !TEST_HARD_REG_BIT (regs, y->color))
2216 pcl = &((*pcl)->next);
2218 *pcl = (*pcl)->next;
2223 /* WEB is a spilled web which was target for coalescing.
2224 Delete all interference edges which were added due to that coalescing,
2225 and break up the coalescing. */
2228 restore_conflicts_from_coalesce (web)
2231 struct conflict_link **pcl;
2232 struct conflict_link *wl;
2233 pcl = &(web->conflict_list);
2234 /* No original conflict list means no conflict was added at all
2235 after building the graph. So neither we nor any neighbors have
2236 conflicts due to this coalescing. */
2237 if (!web->have_orig_conflicts)
2241 struct web *other = (*pcl)->t;
2242 for (wl = web->orig_conflict_list; wl; wl = wl->next)
2247 /* We found this conflict also in the original list, so this
2248 was no new conflict. */
2249 pcl = &((*pcl)->next);
2253 /* This is a new conflict, so delete it from us and
2255 struct conflict_link **opcl;
2256 struct conflict_link *owl;
2257 struct sub_conflict *sl;
2260 if (!other->have_orig_conflicts && other->type != PRECOLORED)
2262 for (owl = other->orig_conflict_list; owl; owl = owl->next)
2267 opcl = &(other->conflict_list);
2270 if ((*opcl)->t == web)
2278 opcl = &((*opcl)->next);
2281 if (!owl && other->type != PRECOLORED)
2283 /* wl and owl contain the edge data to be deleted. */
2284 RESET_BIT (sup_igraph, web->id * num_webs + other->id);
2285 RESET_BIT (sup_igraph, other->id * num_webs + web->id);
2286 RESET_BIT (igraph, igraph_index (web->id, other->id));
2287 for (sl = wl->sub; sl; sl = sl->next)
2288 RESET_BIT (igraph, igraph_index (sl->s->id, sl->t->id));
2289 if (other->type != PRECOLORED)
2291 for (sl = owl->sub; sl; sl = sl->next)
2292 RESET_BIT (igraph, igraph_index (sl->s->id, sl->t->id));
2297 /* We must restore usable_regs because record_conflict will use it. */
2298 COPY_HARD_REG_SET (web->usable_regs, web->orig_usable_regs);
2299 /* We might have deleted some conflicts above, which really are still
2300 there (diamond pattern coalescing). This is because we don't reference
2301 count interference edges but some of them were the result of different
2303 for (wl = web->conflict_list; wl; wl = wl->next)
2304 if (wl->t->type == COALESCED)
2307 for (tweb = wl->t->alias; tweb; tweb = tweb->alias)
2309 if (wl->sub == NULL)
2310 record_conflict (web, tweb);
2313 struct sub_conflict *sl;
2314 for (sl = wl->sub; sl; sl = sl->next)
2316 struct web *sweb = NULL;
2317 if (SUBWEB_P (sl->t))
2318 sweb = find_subweb (tweb, sl->t->orig_x);
2321 record_conflict (sl->s, sweb);
2324 if (tweb->type != COALESCED)
2330 /* Repeatedly break aliases for spilled webs, which were target for
2331 coalescing, and recolorize the resulting parts. Do this as long as
2332 there are any spilled coalesce targets. */
2335 break_coalesced_spills ()
2342 for (d = WEBS(SPILLED); d; d = d->next)
2343 if (DLIST_WEB (d)->is_coalesced)
2348 web = DLIST_WEB (d);
2349 ra_debug_msg (DUMP_COLORIZE, "breaking aliases to web %d:", web->id);
2350 restore_conflicts_from_coalesce (web);
2351 break_aliases_to_web (web);
2352 /* WEB was a spilled web and isn't anymore. Everything coalesced
2353 to WEB is now SELECTed and might potentially get a color.
2354 If those other webs were itself targets of coalescing it might be
2355 that there are still some conflicts from aliased webs missing,
2356 because they were added in combine() right into the now
2357 SELECTed web. So we need to add those missing conflicts here. */
2358 insert_coalesced_conflicts ();
2359 ra_debug_msg (DUMP_COLORIZE, "\n");
2360 remove_list (d, &WEBS(SPILLED));
2361 put_web (web, SELECT);
2363 while (WEBS(SELECT))
2365 d = pop_list (&WEBS(SELECT));
2366 colorize_one_web (DLIST_WEB (d), 1);
2372 for (d = WEBS(COALESCED); d; d = d->next)
2374 struct web *a = alias (DLIST_WEB (d));
2375 DLIST_WEB (d)->color = a->color;
2378 dump_graph_cost (DUMP_COSTS, "after alias-breaking");
2381 /* A structure for fast hashing of a pair of webs.
2382 Used to cumulate savings (from removing copy insns) for coalesced webs.
2383 All the pairs are also put into a single linked list. */
2386 struct web_pair *next_hash;
2387 struct web_pair *next_list;
2388 struct web *smaller;
2390 unsigned int conflicts;
2391 unsigned HOST_WIDE_INT cost;
2394 /* The actual hash table. */
2395 #define WEB_PAIR_HASH_SIZE 8192
2396 static struct web_pair *web_pair_hash[WEB_PAIR_HASH_SIZE];
2397 static struct web_pair *web_pair_list;
2398 static unsigned int num_web_pairs;
2400 /* Clear the hash table of web pairs. */
2405 memset (web_pair_hash, 0, sizeof web_pair_hash);
2407 web_pair_list = NULL;
2410 /* Given two webs connected by a move with cost COST which together
2411 have CONFLICTS conflicts, add that pair to the hash table, or if
2412 already in, cumulate the costs and conflict number. */
2415 add_web_pair_cost (web1, web2, cost, conflicts)
2416 struct web *web1, *web2;
2417 unsigned HOST_WIDE_INT cost;
2418 unsigned int conflicts;
2422 if (web1->id > web2->id)
2424 struct web *h = web1;
2428 hash = (web1->id * num_webs + web2->id) % WEB_PAIR_HASH_SIZE;
2429 for (p = web_pair_hash[hash]; p; p = p->next_hash)
2430 if (p->smaller == web1 && p->larger == web2)
2433 p->conflicts += conflicts;
2436 p = (struct web_pair *) ra_alloc (sizeof *p);
2437 p->next_hash = web_pair_hash[hash];
2438 p->next_list = web_pair_list;
2441 p->conflicts = conflicts;
2443 web_pair_hash[hash] = p;
2448 /* Suitable to be passed to qsort(). Sort web pairs so, that those
2449 with more conflicts and higher cost (which actually is a saving
2450 when the moves are removed) come first. */
2453 comp_web_pairs (w1, w2)
2454 const void *w1, *w2;
2456 struct web_pair *p1 = *(struct web_pair **)w1;
2457 struct web_pair *p2 = *(struct web_pair **)w2;
2458 if (p1->conflicts > p2->conflicts)
2460 else if (p1->conflicts < p2->conflicts)
2462 else if (p1->cost > p2->cost)
2464 else if (p1->cost < p2->cost)
2470 /* Given the list of web pairs, begin to combine them from the one
2471 with the most savings. */
2474 sort_and_combine_web_pairs (for_move)
2478 struct web_pair **sorted;
2482 sorted = (struct web_pair **) xmalloc (num_web_pairs * sizeof (sorted[0]));
2483 for (p = web_pair_list, i = 0; p; p = p->next_list)
2485 if (i != num_web_pairs)
2487 qsort (sorted, num_web_pairs, sizeof (sorted[0]), comp_web_pairs);
2489 /* After combining one pair, we actually should adjust the savings
2490 of the other pairs, if they are connected to one of the just coalesced
2492 for (i = 0; i < num_web_pairs; i++)
2494 struct web *w1, *w2;
2496 w1 = alias (p->smaller);
2497 w2 = alias (p->larger);
2498 if (!for_move && (w1->type == PRECOLORED || w2->type == PRECOLORED))
2500 else if (w2->type == PRECOLORED)
2507 && !TEST_BIT (sup_igraph, w1->id * num_webs + w2->id)
2508 && !TEST_BIT (sup_igraph, w2->id * num_webs + w1->id)
2509 && w2->type != PRECOLORED
2510 && hard_regs_intersect_p (&w1->usable_regs, &w2->usable_regs))
2512 if (w1->type != PRECOLORED
2513 || (w1->type == PRECOLORED && ok (w2, w1)))
2515 else if (w1->type == PRECOLORED)
2516 SET_HARD_REG_BIT (w2->prefer_colors, w1->color);
2522 /* Greedily coalesce all moves possible. Begin with the web pair
2523 giving the most saving if coalesced. */
2526 aggressive_coalesce ()
2531 while ((d = pop_list (&mv_worklist)) != NULL)
2532 if ((m = DLIST_MOVE (d)))
2534 struct web *s = alias (m->source_web);
2535 struct web *t = alias (m->target_web);
2536 if (t->type == PRECOLORED)
2543 && t->type != PRECOLORED
2544 && !TEST_BIT (sup_igraph, s->id * num_webs + t->id)
2545 && !TEST_BIT (sup_igraph, t->id * num_webs + s->id))
2547 if ((s->type == PRECOLORED && ok (t, s))
2548 || s->type != PRECOLORED)
2550 put_move (m, MV_COALESCED);
2551 add_web_pair_cost (s, t, BLOCK_FOR_INSN (m->insn)->frequency,
2554 else if (s->type == PRECOLORED)
2555 /* It is !ok(t, s). But later when coloring the graph it might
2556 be possible to take that color. So we remember the preferred
2557 color to try that first. */
2559 put_move (m, CONSTRAINED);
2560 SET_HARD_REG_BIT (t->prefer_colors, s->color);
2565 put_move (m, CONSTRAINED);
2568 sort_and_combine_web_pairs (1);
2571 /* This is the difference between optimistic coalescing and
2572 optimistic coalescing+. Extended coalesce tries to coalesce also
2573 non-conflicting nodes, not related by a move. The criteria here is,
2574 the one web must be a source, the other a destination of the same insn.
2575 This actually makes sense, as (because they are in the same insn) they
2576 share many of their neighbors, and if they are coalesced, reduce the
2577 number of conflicts of those neighbors by one. For this we sort the
2578 candidate pairs again according to savings (and this time also conflict
2581 This is also a comparatively slow operation, as we need to go through
2582 all insns, and for each insn, through all defs and uses. */
2585 extended_coalesce_2 ()
2588 struct ra_insn_info info;
2591 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
2592 if (INSN_P (insn) && (info = insn_df[INSN_UID (insn)]).num_defs)
2593 for (n = 0; n < info.num_defs; n++)
2595 struct web *dest = def2web[DF_REF_ID (info.defs[n])];
2596 dest = alias (find_web_for_subweb (dest));
2597 if (dest->type != PRECOLORED && dest->regno < max_normal_pseudo)
2600 for (n2 = 0; n2 < info.num_uses; n2++)
2602 struct web *source = use2web[DF_REF_ID (info.uses[n2])];
2603 source = alias (find_web_for_subweb (source));
2604 if (source->type != PRECOLORED
2606 && source->regno < max_normal_pseudo
2607 /* Coalesced webs end up using the same REG rtx in
2608 emit_colors(). So we can only coalesce something
2610 && GET_MODE (source->orig_x) == GET_MODE (dest->orig_x)
2611 && !TEST_BIT (sup_igraph,
2612 dest->id * num_webs + source->id)
2613 && !TEST_BIT (sup_igraph,
2614 source->id * num_webs + dest->id)
2615 && hard_regs_intersect_p (&source->usable_regs,
2616 &dest->usable_regs))
2617 add_web_pair_cost (dest, source,
2618 BLOCK_FOR_INSN (insn)->frequency,
2620 + source->num_conflicts);
2624 sort_and_combine_web_pairs (0);
2627 /* Check if we forgot to coalesce some moves. */
2630 check_uncoalesced_moves ()
2632 struct move_list *ml;
2634 for (ml = wl_moves; ml; ml = ml->next)
2637 struct web *s = alias (m->source_web);
2638 struct web *t = alias (m->target_web);
2639 if (t->type == PRECOLORED)
2646 && m->type != CONSTRAINED
2647 /* Following can happen when a move was coalesced, but later
2648 broken up again. Then s!=t, but m is still MV_COALESCED. */
2649 && m->type != MV_COALESCED
2650 && t->type != PRECOLORED
2651 && ((s->type == PRECOLORED && ok (t, s))
2652 || s->type != PRECOLORED)
2653 && !TEST_BIT (sup_igraph, s->id * num_webs + t->id)
2654 && !TEST_BIT (sup_igraph, t->id * num_webs + s->id))
2659 /* The toplevel function in this file. Precondition is, that
2660 the interference graph is built completely by ra-build.c. This
2661 produces a list of spilled, colored and coalesced nodes. */
2664 ra_colorize_graph (df)
2669 build_worklists (df);
2671 /* With optimistic coalescing we coalesce everything we can. */
2672 if (flag_ra_optimistic_coalescing)
2674 aggressive_coalesce ();
2675 extended_coalesce_2 ();
2678 /* Now build the select stack. */
2684 else if (WEBS(FREEZE))
2686 else if (WEBS(SPILL))
2689 while (WEBS(SIMPLIFY) || WEBS(SIMPLIFY_FAT) || WEBS(SIMPLIFY_SPILL)
2690 || mv_worklist || WEBS(FREEZE) || WEBS(SPILL));
2691 if (flag_ra_optimistic_coalescing)
2692 check_uncoalesced_moves ();
2694 /* Actually colorize the webs from the select stack. */
2697 dump_graph_cost (DUMP_COSTS, "initially");
2698 if (flag_ra_break_aliases)
2699 break_coalesced_spills ();
2702 /* And try to improve the cost by recoloring spilled webs. */
2704 dump_graph_cost (DUMP_COSTS, "after spill-recolor");
2708 /* Initialize this module. */
2710 void ra_colorize_init ()
2712 /* FIXME: Choose spill heuristic for platform if we have one */
2713 spill_heuristic = default_spill_heuristic;
2716 /* Free all memory. (Note that we don't need to free any per pass
2720 ra_colorize_free_all ()
2723 while ((d = pop_list (&WEBS(FREE))) != NULL)
2724 put_web (DLIST_WEB (d), INITIAL);
2725 while ((d = pop_list (&WEBS(INITIAL))) != NULL)
2727 struct web *web =DLIST_WEB (d);
2729 web->orig_conflict_list = NULL;
2730 web->conflict_list = NULL;
2731 for (web = web->subreg_next; web; web = wnext)
2733 wnext = web->subreg_next;
2736 free (DLIST_WEB (d));
2741 vim:cinoptions={.5s,g0,p5,t0,(0,^-0.5s,n-0.5s:tw=78:cindent:sw=4: