1 /* CPU mode switching
2 Copyright (C) 1998-2018 Free Software Foundation, Inc.
3
4 This file is part of GCC.
5
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
10
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
19
20 #include "config.h"
21 #include "system.h"
22 #include "coretypes.h"
23 #include "backend.h"
24 #include "target.h"
25 #include "rtl.h"
26 #include "cfghooks.h"
27 #include "df.h"
28 #include "memmodel.h"
29 #include "tm_p.h"
30 #include "regs.h"
31 #include "emit-rtl.h"
32 #include "cfgrtl.h"
33 #include "cfganal.h"
34 #include "lcm.h"
35 #include "cfgcleanup.h"
36 #include "tree-pass.h"
37
38 /* We want target macros for the mode switching code to be able to refer
39 to instruction attribute values. */
40 #include "insn-attr.h"
41
42 #ifdef OPTIMIZE_MODE_SWITCHING
43
44 /* The algorithm for setting the modes consists of scanning the insn list
45 and finding all the insns which require a specific mode. Each insn gets
46 a unique struct seginfo element. These structures are inserted into a list
47 for each basic block. For each entity, there is an array of bb_info over
48 the flow graph basic blocks (local var 'bb_info'), which contains a list
49 of all insns within that basic block, in the order they are encountered.
50
51 For each entity, any basic block WITHOUT any insns requiring a specific
52 mode are given a single entry without a mode (each basic block in the
53 flow graph must have at least one entry in the segment table).
54
55 The LCM algorithm is then run over the flow graph to determine where to
56 place the sets to the highest-priority mode with respect to the first
57 insn in any one block. Any adjustments required to the transparency
58 vectors are made, then the next iteration starts for the next-lower
59 priority mode, till for each entity all modes are exhausted.
60
61 More details can be found in the code of optimize_mode_switching. */
62
63 /* This structure contains the information for each insn which requires
64 either single or double mode to be set.
65 MODE is the mode this insn must be executed in.
66 INSN_PTR is the insn to be executed (may be the note that marks the
67 beginning of a basic block).
68 BBNUM is the flow graph basic block this insn occurs in.
69 NEXT is the next insn in the same basic block. */
70 struct seginfo
71 {
72 int mode;
73 rtx_insn *insn_ptr;
74 int bbnum;
75 struct seginfo *next;
76 HARD_REG_SET regs_live;
77 };
78
79 struct bb_info
80 {
81 struct seginfo *seginfo;
82 int computing;
83 int mode_out;
84 int mode_in;
85 };
86
87 static struct seginfo * new_seginfo (int, rtx_insn *, int, HARD_REG_SET);
88 static void add_seginfo (struct bb_info *, struct seginfo *);
89 static void reg_dies (rtx, HARD_REG_SET *);
90 static void reg_becomes_live (rtx, const_rtx, void *);
91
92 /* Clear ode I from entity J in bitmap B. */
93 #define clear_mode_bit(b, j, i) \
94 bitmap_clear_bit (b, (j * max_num_modes) + i)
95
96 /* Test mode I from entity J in bitmap B. */
97 #define mode_bit_p(b, j, i) \
98 bitmap_bit_p (b, (j * max_num_modes) + i)
99
100 /* Set mode I from entity J in bitmal B. */
101 #define set_mode_bit(b, j, i) \
102 bitmap_set_bit (b, (j * max_num_modes) + i)
103
104 /* Emit modes segments from EDGE_LIST associated with entity E.
105 INFO gives mode availability for each mode. */
106
107 static bool
commit_mode_sets(struct edge_list * edge_list,int e,struct bb_info * info)108 commit_mode_sets (struct edge_list *edge_list, int e, struct bb_info *info)
109 {
110 bool need_commit = false;
111
112 for (int ed = NUM_EDGES (edge_list) - 1; ed >= 0; ed--)
113 {
114 edge eg = INDEX_EDGE (edge_list, ed);
115 int mode;
116
117 if ((mode = (int)(intptr_t)(eg->aux)) != -1)
118 {
119 HARD_REG_SET live_at_edge;
120 basic_block src_bb = eg->src;
121 int cur_mode = info[src_bb->index].mode_out;
122 rtx_insn *mode_set;
123
124 REG_SET_TO_HARD_REG_SET (live_at_edge, df_get_live_out (src_bb));
125
126 rtl_profile_for_edge (eg);
127 start_sequence ();
128
129 targetm.mode_switching.emit (e, mode, cur_mode, live_at_edge);
130
131 mode_set = get_insns ();
132 end_sequence ();
133 default_rtl_profile ();
134
135 /* Do not bother to insert empty sequence. */
136 if (mode_set == NULL)
137 continue;
138
139 /* We should not get an abnormal edge here. */
140 gcc_assert (! (eg->flags & EDGE_ABNORMAL));
141
142 need_commit = true;
143 insert_insn_on_edge (mode_set, eg);
144 }
145 }
146
147 return need_commit;
148 }
149
150 /* Allocate a new BBINFO structure, initialized with the MODE, INSN,
151 and basic block BB parameters.
152 INSN may not be a NOTE_INSN_BASIC_BLOCK, unless it is an empty
153 basic block; that allows us later to insert instructions in a FIFO-like
154 manner. */
155
156 static struct seginfo *
new_seginfo(int mode,rtx_insn * insn,int bb,HARD_REG_SET regs_live)157 new_seginfo (int mode, rtx_insn *insn, int bb, HARD_REG_SET regs_live)
158 {
159 struct seginfo *ptr;
160
161 gcc_assert (!NOTE_INSN_BASIC_BLOCK_P (insn)
162 || insn == BB_END (NOTE_BASIC_BLOCK (insn)));
163 ptr = XNEW (struct seginfo);
164 ptr->mode = mode;
165 ptr->insn_ptr = insn;
166 ptr->bbnum = bb;
167 ptr->next = NULL;
168 COPY_HARD_REG_SET (ptr->regs_live, regs_live);
169 return ptr;
170 }
171
172 /* Add a seginfo element to the end of a list.
173 HEAD is a pointer to the list beginning.
174 INFO is the structure to be linked in. */
175
176 static void
add_seginfo(struct bb_info * head,struct seginfo * info)177 add_seginfo (struct bb_info *head, struct seginfo *info)
178 {
179 struct seginfo *ptr;
180
181 if (head->seginfo == NULL)
182 head->seginfo = info;
183 else
184 {
185 ptr = head->seginfo;
186 while (ptr->next != NULL)
187 ptr = ptr->next;
188 ptr->next = info;
189 }
190 }
191
192 /* Record in LIVE that register REG died. */
193
194 static void
reg_dies(rtx reg,HARD_REG_SET * live)195 reg_dies (rtx reg, HARD_REG_SET *live)
196 {
197 int regno;
198
199 if (!REG_P (reg))
200 return;
201
202 regno = REGNO (reg);
203 if (regno < FIRST_PSEUDO_REGISTER)
204 remove_from_hard_reg_set (live, GET_MODE (reg), regno);
205 }
206
207 /* Record in LIVE that register REG became live.
208 This is called via note_stores. */
209
210 static void
reg_becomes_live(rtx reg,const_rtx setter ATTRIBUTE_UNUSED,void * live)211 reg_becomes_live (rtx reg, const_rtx setter ATTRIBUTE_UNUSED, void *live)
212 {
213 int regno;
214
215 if (GET_CODE (reg) == SUBREG)
216 reg = SUBREG_REG (reg);
217
218 if (!REG_P (reg))
219 return;
220
221 regno = REGNO (reg);
222 if (regno < FIRST_PSEUDO_REGISTER)
223 add_to_hard_reg_set ((HARD_REG_SET *) live, GET_MODE (reg), regno);
224 }
225
226 /* Split the fallthrough edge to the exit block, so that we can note
227 that there NORMAL_MODE is required. Return the new block if it's
228 inserted before the exit block. Otherwise return null. */
229
230 static basic_block
create_pre_exit(int n_entities,int * entity_map,const int * num_modes)231 create_pre_exit (int n_entities, int *entity_map, const int *num_modes)
232 {
233 edge eg;
234 edge_iterator ei;
235 basic_block pre_exit;
236
237 /* The only non-call predecessor at this stage is a block with a
238 fallthrough edge; there can be at most one, but there could be
239 none at all, e.g. when exit is called. */
240 pre_exit = 0;
241 FOR_EACH_EDGE (eg, ei, EXIT_BLOCK_PTR_FOR_FN (cfun)->preds)
242 if (eg->flags & EDGE_FALLTHRU)
243 {
244 basic_block src_bb = eg->src;
245 rtx_insn *last_insn;
246 rtx ret_reg;
247
248 gcc_assert (!pre_exit);
249 /* If this function returns a value at the end, we have to
250 insert the final mode switch before the return value copy
251 to its hard register. */
252 if (EDGE_COUNT (EXIT_BLOCK_PTR_FOR_FN (cfun)->preds) == 1
253 && NONJUMP_INSN_P ((last_insn = BB_END (src_bb)))
254 && GET_CODE (PATTERN (last_insn)) == USE
255 && GET_CODE ((ret_reg = XEXP (PATTERN (last_insn), 0))) == REG)
256 {
257 int ret_start = REGNO (ret_reg);
258 int nregs = REG_NREGS (ret_reg);
259 int ret_end = ret_start + nregs;
260 bool short_block = false;
261 bool multi_reg_return = false;
262 bool forced_late_switch = false;
263 rtx_insn *before_return_copy;
264
265 do
266 {
267 rtx_insn *return_copy = PREV_INSN (last_insn);
268 rtx return_copy_pat, copy_reg;
269 int copy_start, copy_num;
270 int j;
271
272 if (NONDEBUG_INSN_P (return_copy))
273 {
274 /* When using SJLJ exceptions, the call to the
275 unregister function is inserted between the
276 clobber of the return value and the copy.
277 We do not want to split the block before this
278 or any other call; if we have not found the
279 copy yet, the copy must have been deleted. */
280 if (CALL_P (return_copy))
281 {
282 short_block = true;
283 break;
284 }
285 return_copy_pat = PATTERN (return_copy);
286 switch (GET_CODE (return_copy_pat))
287 {
288 case USE:
289 /* Skip USEs of multiple return registers.
290 __builtin_apply pattern is also handled here. */
291 if (GET_CODE (XEXP (return_copy_pat, 0)) == REG
292 && (targetm.calls.function_value_regno_p
293 (REGNO (XEXP (return_copy_pat, 0)))))
294 {
295 multi_reg_return = true;
296 last_insn = return_copy;
297 continue;
298 }
299 break;
300
301 case ASM_OPERANDS:
302 /* Skip barrier insns. */
303 if (!MEM_VOLATILE_P (return_copy_pat))
304 break;
305
306 /* Fall through. */
307
308 case ASM_INPUT:
309 case UNSPEC_VOLATILE:
310 last_insn = return_copy;
311 continue;
312
313 default:
314 break;
315 }
316
317 /* If the return register is not (in its entirety)
318 likely spilled, the return copy might be
319 partially or completely optimized away. */
320 return_copy_pat = single_set (return_copy);
321 if (!return_copy_pat)
322 {
323 return_copy_pat = PATTERN (return_copy);
324 if (GET_CODE (return_copy_pat) != CLOBBER)
325 break;
326 else if (!optimize)
327 {
328 /* This might be (clobber (reg [<result>]))
329 when not optimizing. Then check if
330 the previous insn is the clobber for
331 the return register. */
332 copy_reg = SET_DEST (return_copy_pat);
333 if (GET_CODE (copy_reg) == REG
334 && !HARD_REGISTER_NUM_P (REGNO (copy_reg)))
335 {
336 if (INSN_P (PREV_INSN (return_copy)))
337 {
338 return_copy = PREV_INSN (return_copy);
339 return_copy_pat = PATTERN (return_copy);
340 if (GET_CODE (return_copy_pat) != CLOBBER)
341 break;
342 }
343 }
344 }
345 }
346 copy_reg = SET_DEST (return_copy_pat);
347 if (GET_CODE (copy_reg) == REG)
348 copy_start = REGNO (copy_reg);
349 else if (GET_CODE (copy_reg) == SUBREG
350 && GET_CODE (SUBREG_REG (copy_reg)) == REG)
351 copy_start = REGNO (SUBREG_REG (copy_reg));
352 else
353 {
354 /* When control reaches end of non-void function,
355 there are no return copy insns at all. This
356 avoids an ice on that invalid function. */
357 if (ret_start + nregs == ret_end)
358 short_block = true;
359 break;
360 }
361 if (!targetm.calls.function_value_regno_p (copy_start))
362 copy_num = 0;
363 else
364 copy_num = hard_regno_nregs (copy_start,
365 GET_MODE (copy_reg));
366
367 /* If the return register is not likely spilled, - as is
368 the case for floating point on SH4 - then it might
369 be set by an arithmetic operation that needs a
370 different mode than the exit block. */
371 for (j = n_entities - 1; j >= 0; j--)
372 {
373 int e = entity_map[j];
374 int mode =
375 targetm.mode_switching.needed (e, return_copy);
376
377 if (mode != num_modes[e]
378 && mode != targetm.mode_switching.exit (e))
379 break;
380 }
381 if (j >= 0)
382 {
383 /* __builtin_return emits a sequence of loads to all
384 return registers. One of them might require
385 another mode than MODE_EXIT, even if it is
386 unrelated to the return value, so we want to put
387 the final mode switch after it. */
388 if (multi_reg_return
389 && targetm.calls.function_value_regno_p
390 (copy_start))
391 forced_late_switch = true;
392
393 /* For the SH4, floating point loads depend on fpscr,
394 thus we might need to put the final mode switch
395 after the return value copy. That is still OK,
396 because a floating point return value does not
397 conflict with address reloads. */
398 if (copy_start >= ret_start
399 && copy_start + copy_num <= ret_end
400 && OBJECT_P (SET_SRC (return_copy_pat)))
401 forced_late_switch = true;
402 break;
403 }
404 if (copy_num == 0)
405 {
406 last_insn = return_copy;
407 continue;
408 }
409
410 if (copy_start >= ret_start
411 && copy_start + copy_num <= ret_end)
412 nregs -= copy_num;
413 else if (!multi_reg_return
414 || !targetm.calls.function_value_regno_p
415 (copy_start))
416 break;
417 last_insn = return_copy;
418 }
419 /* ??? Exception handling can lead to the return value
420 copy being already separated from the return value use,
421 as in unwind-dw2.c .
422 Similarly, conditionally returning without a value,
423 and conditionally using builtin_return can lead to an
424 isolated use. */
425 if (return_copy == BB_HEAD (src_bb))
426 {
427 short_block = true;
428 break;
429 }
430 last_insn = return_copy;
431 }
432 while (nregs);
433
434 /* If we didn't see a full return value copy, verify that there
435 is a plausible reason for this. If some, but not all of the
436 return register is likely spilled, we can expect that there
437 is a copy for the likely spilled part. */
438 gcc_assert (!nregs
439 || forced_late_switch
440 || short_block
441 || !(targetm.class_likely_spilled_p
442 (REGNO_REG_CLASS (ret_start)))
443 || nregs != REG_NREGS (ret_reg)
444 /* For multi-hard-register floating point
445 values, sometimes the likely-spilled part
446 is ordinarily copied first, then the other
447 part is set with an arithmetic operation.
448 This doesn't actually cause reload
449 failures, so let it pass. */
450 || (GET_MODE_CLASS (GET_MODE (ret_reg)) != MODE_INT
451 && nregs != 1));
452
453 if (!NOTE_INSN_BASIC_BLOCK_P (last_insn))
454 {
455 before_return_copy
456 = emit_note_before (NOTE_INSN_DELETED, last_insn);
457 /* Instructions preceding LAST_INSN in the same block might
458 require a different mode than MODE_EXIT, so if we might
459 have such instructions, keep them in a separate block
460 from pre_exit. */
461 src_bb = split_block (src_bb,
462 PREV_INSN (before_return_copy))->dest;
463 }
464 else
465 before_return_copy = last_insn;
466 pre_exit = split_block (src_bb, before_return_copy)->src;
467 }
468 else
469 {
470 pre_exit = split_edge (eg);
471 }
472 }
473
474 return pre_exit;
475 }
476
477 /* Find all insns that need a particular mode setting, and insert the
478 necessary mode switches. Return true if we did work. */
479
480 static int
optimize_mode_switching(void)481 optimize_mode_switching (void)
482 {
483 int e;
484 basic_block bb;
485 bool need_commit = false;
486 static const int num_modes[] = NUM_MODES_FOR_MODE_SWITCHING;
487 #define N_ENTITIES ARRAY_SIZE (num_modes)
488 int entity_map[N_ENTITIES];
489 struct bb_info *bb_info[N_ENTITIES];
490 int i, j;
491 int n_entities = 0;
492 int max_num_modes = 0;
493 bool emitted ATTRIBUTE_UNUSED = false;
494 basic_block post_entry = 0;
495 basic_block pre_exit = 0;
496 struct edge_list *edge_list = 0;
497
498 /* These bitmaps are used for the LCM algorithm. */
499 sbitmap *kill, *del, *insert, *antic, *transp, *comp;
500 sbitmap *avin, *avout;
501
502 for (e = N_ENTITIES - 1; e >= 0; e--)
503 if (OPTIMIZE_MODE_SWITCHING (e))
504 {
505 int entry_exit_extra = 0;
506
507 /* Create the list of segments within each basic block.
508 If NORMAL_MODE is defined, allow for two extra
509 blocks split from the entry and exit block. */
510 if (targetm.mode_switching.entry && targetm.mode_switching.exit)
511 entry_exit_extra = 3;
512
513 bb_info[n_entities]
514 = XCNEWVEC (struct bb_info,
515 last_basic_block_for_fn (cfun) + entry_exit_extra);
516 entity_map[n_entities++] = e;
517 if (num_modes[e] > max_num_modes)
518 max_num_modes = num_modes[e];
519 }
520
521 if (! n_entities)
522 return 0;
523
524 /* Make sure if MODE_ENTRY is defined MODE_EXIT is defined. */
525 gcc_assert ((targetm.mode_switching.entry && targetm.mode_switching.exit)
526 || (!targetm.mode_switching.entry
527 && !targetm.mode_switching.exit));
528
529 if (targetm.mode_switching.entry && targetm.mode_switching.exit)
530 {
531 /* Split the edge from the entry block, so that we can note that
532 there NORMAL_MODE is supplied. */
533 post_entry = split_edge (single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun)));
534 pre_exit = create_pre_exit (n_entities, entity_map, num_modes);
535 }
536
537 df_analyze ();
538
539 /* Create the bitmap vectors. */
540 antic = sbitmap_vector_alloc (last_basic_block_for_fn (cfun),
541 n_entities * max_num_modes);
542 transp = sbitmap_vector_alloc (last_basic_block_for_fn (cfun),
543 n_entities * max_num_modes);
544 comp = sbitmap_vector_alloc (last_basic_block_for_fn (cfun),
545 n_entities * max_num_modes);
546 avin = sbitmap_vector_alloc (last_basic_block_for_fn (cfun),
547 n_entities * max_num_modes);
548 avout = sbitmap_vector_alloc (last_basic_block_for_fn (cfun),
549 n_entities * max_num_modes);
550 kill = sbitmap_vector_alloc (last_basic_block_for_fn (cfun),
551 n_entities * max_num_modes);
552
553 bitmap_vector_ones (transp, last_basic_block_for_fn (cfun));
554 bitmap_vector_clear (antic, last_basic_block_for_fn (cfun));
555 bitmap_vector_clear (comp, last_basic_block_for_fn (cfun));
556
557 for (j = n_entities - 1; j >= 0; j--)
558 {
559 int e = entity_map[j];
560 int no_mode = num_modes[e];
561 struct bb_info *info = bb_info[j];
562 rtx_insn *insn;
563
564 /* Determine what the first use (if any) need for a mode of entity E is.
565 This will be the mode that is anticipatable for this block.
566 Also compute the initial transparency settings. */
567 FOR_EACH_BB_FN (bb, cfun)
568 {
569 struct seginfo *ptr;
570 int last_mode = no_mode;
571 bool any_set_required = false;
572 HARD_REG_SET live_now;
573
574 info[bb->index].mode_out = info[bb->index].mode_in = no_mode;
575
576 REG_SET_TO_HARD_REG_SET (live_now, df_get_live_in (bb));
577
578 /* Pretend the mode is clobbered across abnormal edges. */
579 {
580 edge_iterator ei;
581 edge eg;
582 FOR_EACH_EDGE (eg, ei, bb->preds)
583 if (eg->flags & EDGE_COMPLEX)
584 break;
585 if (eg)
586 {
587 rtx_insn *ins_pos = BB_HEAD (bb);
588 if (LABEL_P (ins_pos))
589 ins_pos = NEXT_INSN (ins_pos);
590 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (ins_pos));
591 if (ins_pos != BB_END (bb))
592 ins_pos = NEXT_INSN (ins_pos);
593 ptr = new_seginfo (no_mode, ins_pos, bb->index, live_now);
594 add_seginfo (info + bb->index, ptr);
595 for (i = 0; i < no_mode; i++)
596 clear_mode_bit (transp[bb->index], j, i);
597 }
598 }
599
600 FOR_BB_INSNS (bb, insn)
601 {
602 if (INSN_P (insn))
603 {
604 int mode = targetm.mode_switching.needed (e, insn);
605 rtx link;
606
607 if (mode != no_mode && mode != last_mode)
608 {
609 any_set_required = true;
610 last_mode = mode;
611 ptr = new_seginfo (mode, insn, bb->index, live_now);
612 add_seginfo (info + bb->index, ptr);
613 for (i = 0; i < no_mode; i++)
614 clear_mode_bit (transp[bb->index], j, i);
615 }
616
617 if (targetm.mode_switching.after)
618 last_mode = targetm.mode_switching.after (e, last_mode,
619 insn);
620
621 /* Update LIVE_NOW. */
622 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
623 if (REG_NOTE_KIND (link) == REG_DEAD)
624 reg_dies (XEXP (link, 0), &live_now);
625
626 note_stores (PATTERN (insn), reg_becomes_live, &live_now);
627 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
628 if (REG_NOTE_KIND (link) == REG_UNUSED)
629 reg_dies (XEXP (link, 0), &live_now);
630 }
631 }
632
633 info[bb->index].computing = last_mode;
634 /* Check for blocks without ANY mode requirements.
635 N.B. because of MODE_AFTER, last_mode might still
636 be different from no_mode, in which case we need to
637 mark the block as nontransparent. */
638 if (!any_set_required)
639 {
640 ptr = new_seginfo (no_mode, BB_END (bb), bb->index, live_now);
641 add_seginfo (info + bb->index, ptr);
642 if (last_mode != no_mode)
643 for (i = 0; i < no_mode; i++)
644 clear_mode_bit (transp[bb->index], j, i);
645 }
646 }
647 if (targetm.mode_switching.entry && targetm.mode_switching.exit)
648 {
649 int mode = targetm.mode_switching.entry (e);
650
651 info[post_entry->index].mode_out =
652 info[post_entry->index].mode_in = no_mode;
653 if (pre_exit)
654 {
655 info[pre_exit->index].mode_out =
656 info[pre_exit->index].mode_in = no_mode;
657 }
658
659 if (mode != no_mode)
660 {
661 bb = post_entry;
662
663 /* By always making this nontransparent, we save
664 an extra check in make_preds_opaque. We also
665 need this to avoid confusing pre_edge_lcm when
666 antic is cleared but transp and comp are set. */
667 for (i = 0; i < no_mode; i++)
668 clear_mode_bit (transp[bb->index], j, i);
669
670 /* Insert a fake computing definition of MODE into entry
671 blocks which compute no mode. This represents the mode on
672 entry. */
673 info[bb->index].computing = mode;
674
675 if (pre_exit)
676 info[pre_exit->index].seginfo->mode =
677 targetm.mode_switching.exit (e);
678 }
679 }
680
681 /* Set the anticipatable and computing arrays. */
682 for (i = 0; i < no_mode; i++)
683 {
684 int m = targetm.mode_switching.priority (entity_map[j], i);
685
686 FOR_EACH_BB_FN (bb, cfun)
687 {
688 if (info[bb->index].seginfo->mode == m)
689 set_mode_bit (antic[bb->index], j, m);
690
691 if (info[bb->index].computing == m)
692 set_mode_bit (comp[bb->index], j, m);
693 }
694 }
695 }
696
697 /* Calculate the optimal locations for the
698 placement mode switches to modes with priority I. */
699
700 FOR_EACH_BB_FN (bb, cfun)
701 bitmap_not (kill[bb->index], transp[bb->index]);
702
703 edge_list = pre_edge_lcm_avs (n_entities * max_num_modes, transp, comp, antic,
704 kill, avin, avout, &insert, &del);
705
706 for (j = n_entities - 1; j >= 0; j--)
707 {
708 int no_mode = num_modes[entity_map[j]];
709
710 /* Insert all mode sets that have been inserted by lcm. */
711
712 for (int ed = NUM_EDGES (edge_list) - 1; ed >= 0; ed--)
713 {
714 edge eg = INDEX_EDGE (edge_list, ed);
715
716 eg->aux = (void *)(intptr_t)-1;
717
718 for (i = 0; i < no_mode; i++)
719 {
720 int m = targetm.mode_switching.priority (entity_map[j], i);
721 if (mode_bit_p (insert[ed], j, m))
722 {
723 eg->aux = (void *)(intptr_t)m;
724 break;
725 }
726 }
727 }
728
729 FOR_EACH_BB_FN (bb, cfun)
730 {
731 struct bb_info *info = bb_info[j];
732 int last_mode = no_mode;
733
734 /* intialize mode in availability for bb. */
735 for (i = 0; i < no_mode; i++)
736 if (mode_bit_p (avout[bb->index], j, i))
737 {
738 if (last_mode == no_mode)
739 last_mode = i;
740 if (last_mode != i)
741 {
742 last_mode = no_mode;
743 break;
744 }
745 }
746 info[bb->index].mode_out = last_mode;
747
748 /* intialize mode out availability for bb. */
749 last_mode = no_mode;
750 for (i = 0; i < no_mode; i++)
751 if (mode_bit_p (avin[bb->index], j, i))
752 {
753 if (last_mode == no_mode)
754 last_mode = i;
755 if (last_mode != i)
756 {
757 last_mode = no_mode;
758 break;
759 }
760 }
761 info[bb->index].mode_in = last_mode;
762
763 for (i = 0; i < no_mode; i++)
764 if (mode_bit_p (del[bb->index], j, i))
765 info[bb->index].seginfo->mode = no_mode;
766 }
767
768 /* Now output the remaining mode sets in all the segments. */
769
770 /* In case there was no mode inserted. the mode information on the edge
771 might not be complete.
772 Update mode info on edges and commit pending mode sets. */
773 need_commit |= commit_mode_sets (edge_list, entity_map[j], bb_info[j]);
774
775 /* Reset modes for next entity. */
776 clear_aux_for_edges ();
777
778 FOR_EACH_BB_FN (bb, cfun)
779 {
780 struct seginfo *ptr, *next;
781 int cur_mode = bb_info[j][bb->index].mode_in;
782
783 for (ptr = bb_info[j][bb->index].seginfo; ptr; ptr = next)
784 {
785 next = ptr->next;
786 if (ptr->mode != no_mode)
787 {
788 rtx_insn *mode_set;
789
790 rtl_profile_for_bb (bb);
791 start_sequence ();
792
793 targetm.mode_switching.emit (entity_map[j], ptr->mode,
794 cur_mode, ptr->regs_live);
795 mode_set = get_insns ();
796 end_sequence ();
797
798 /* modes kill each other inside a basic block. */
799 cur_mode = ptr->mode;
800
801 /* Insert MODE_SET only if it is nonempty. */
802 if (mode_set != NULL_RTX)
803 {
804 emitted = true;
805 if (NOTE_INSN_BASIC_BLOCK_P (ptr->insn_ptr))
806 /* We need to emit the insns in a FIFO-like manner,
807 i.e. the first to be emitted at our insertion
808 point ends up first in the instruction steam.
809 Because we made sure that NOTE_INSN_BASIC_BLOCK is
810 only used for initially empty basic blocks, we
811 can achieve this by appending at the end of
812 the block. */
813 emit_insn_after
814 (mode_set, BB_END (NOTE_BASIC_BLOCK (ptr->insn_ptr)));
815 else
816 emit_insn_before (mode_set, ptr->insn_ptr);
817 }
818
819 default_rtl_profile ();
820 }
821
822 free (ptr);
823 }
824 }
825
826 free (bb_info[j]);
827 }
828
829 free_edge_list (edge_list);
830
831 /* Finished. Free up all the things we've allocated. */
832 sbitmap_vector_free (del);
833 sbitmap_vector_free (insert);
834 sbitmap_vector_free (kill);
835 sbitmap_vector_free (antic);
836 sbitmap_vector_free (transp);
837 sbitmap_vector_free (comp);
838 sbitmap_vector_free (avin);
839 sbitmap_vector_free (avout);
840
841 if (need_commit)
842 commit_edge_insertions ();
843
844 if (targetm.mode_switching.entry && targetm.mode_switching.exit)
845 cleanup_cfg (CLEANUP_NO_INSN_DEL);
846 else if (!need_commit && !emitted)
847 return 0;
848
849 return 1;
850 }
851
852 #endif /* OPTIMIZE_MODE_SWITCHING */
853
854 namespace {
855
856 const pass_data pass_data_mode_switching =
857 {
858 RTL_PASS, /* type */
859 "mode_sw", /* name */
860 OPTGROUP_NONE, /* optinfo_flags */
861 TV_MODE_SWITCH, /* tv_id */
862 0, /* properties_required */
863 0, /* properties_provided */
864 0, /* properties_destroyed */
865 0, /* todo_flags_start */
866 TODO_df_finish, /* todo_flags_finish */
867 };
868
869 class pass_mode_switching : public rtl_opt_pass
870 {
871 public:
pass_mode_switching(gcc::context * ctxt)872 pass_mode_switching (gcc::context *ctxt)
873 : rtl_opt_pass (pass_data_mode_switching, ctxt)
874 {}
875
876 /* opt_pass methods: */
877 /* The epiphany backend creates a second instance of this pass, so we need
878 a clone method. */
clone()879 opt_pass * clone () { return new pass_mode_switching (m_ctxt); }
gate(function *)880 virtual bool gate (function *)
881 {
882 #ifdef OPTIMIZE_MODE_SWITCHING
883 return true;
884 #else
885 return false;
886 #endif
887 }
888
execute(function *)889 virtual unsigned int execute (function *)
890 {
891 #ifdef OPTIMIZE_MODE_SWITCHING
892 optimize_mode_switching ();
893 #endif /* OPTIMIZE_MODE_SWITCHING */
894 return 0;
895 }
896
897 }; // class pass_mode_switching
898
899 } // anon namespace
900
901 rtl_opt_pass *
make_pass_mode_switching(gcc::context * ctxt)902 make_pass_mode_switching (gcc::context *ctxt)
903 {
904 return new pass_mode_switching (ctxt);
905 }
906