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[/] [openrisc/] [trunk/] [gnu-src/] [gcc-4.5.1/] [gcc/] [regrename.c] - Blame information for rev 280

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1 280 jeremybenn
/* Register renaming for the GNU compiler.
2
   Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
3
   2010 Free Software Foundation, Inc.
4
 
5
   This file is part of GCC.
6
 
7
   GCC is free software; you can redistribute it and/or modify it
8
   under the terms of the GNU General Public License as published by
9
   the Free Software Foundation; either version 3, or (at your option)
10
   any later version.
11
 
12
   GCC is distributed in the hope that it will be useful, but WITHOUT
13
   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14
   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
15
   License for more details.
16
 
17
   You should have received a copy of the GNU General Public License
18
   along with GCC; see the file COPYING3.  If not see
19
   <http://www.gnu.org/licenses/>.  */
20
 
21
#include "config.h"
22
#include "system.h"
23
#include "coretypes.h"
24
#include "tm.h"
25
#include "rtl.h"
26
#include "tm_p.h"
27
#include "insn-config.h"
28
#include "regs.h"
29
#include "addresses.h"
30
#include "hard-reg-set.h"
31
#include "basic-block.h"
32
#include "reload.h"
33
#include "output.h"
34
#include "function.h"
35
#include "recog.h"
36
#include "flags.h"
37
#include "toplev.h"
38
#include "obstack.h"
39
#include "timevar.h"
40
#include "tree-pass.h"
41
#include "df.h"
42
 
43
#if HOST_BITS_PER_WIDE_INT <= MAX_RECOG_OPERANDS
44
#error "Use a different bitmap implementation for untracked_operands."
45
#endif
46
 
47
/* We keep linked lists of DU_HEAD structures, each of which describes
48
   a chain of occurrences of a reg.  */
49
struct du_head
50
{
51
  /* The next chain.  */
52
  struct du_head *next_chain;
53
  /* The first and last elements of this chain.  */
54
  struct du_chain *first, *last;
55
  /* Describes the register being tracked.  */
56
  unsigned regno, nregs;
57
 
58
  /* A unique id to be used as an index into the conflicts bitmaps.  */
59
  unsigned id;
60
  /* A bitmap to record conflicts with other chains.  */
61
  bitmap_head conflicts;
62
  /* Conflicts with untracked hard registers.  */
63
  HARD_REG_SET hard_conflicts;
64
 
65
  /* Nonzero if the chain is finished; zero if it is still open.  */
66
  unsigned int terminated:1;
67
  /* Nonzero if the chain crosses a call.  */
68
  unsigned int need_caller_save_reg:1;
69
  /* Nonzero if the register is used in a way that prevents renaming,
70
     such as the SET_DEST of a CALL_INSN or an asm operand that used
71
     to be a hard register.  */
72
  unsigned int cannot_rename:1;
73
};
74
 
75
/* This struct describes a single occurrence of a register.  */
76
struct du_chain
77
{
78
  /* Links to the next occurrence of the register.  */
79
  struct du_chain *next_use;
80
 
81
  /* The insn where the register appears.  */
82
  rtx insn;
83
  /* The location inside the insn.  */
84
  rtx *loc;
85
  /* The register class required by the insn at this location.  */
86
  ENUM_BITFIELD(reg_class) cl : 16;
87
};
88
 
89
enum scan_actions
90
{
91
  terminate_write,
92
  terminate_dead,
93
  mark_all_read,
94
  mark_read,
95
  mark_write,
96
  /* mark_access is for marking the destination regs in
97
     REG_FRAME_RELATED_EXPR notes (as if they were read) so that the
98
     note is updated properly.  */
99
  mark_access
100
};
101
 
102
static const char * const scan_actions_name[] =
103
{
104
  "terminate_write",
105
  "terminate_dead",
106
  "mark_all_read",
107
  "mark_read",
108
  "mark_write",
109
  "mark_access"
110
};
111
 
112
static struct obstack rename_obstack;
113
 
114
static void do_replace (struct du_head *, int);
115
static void scan_rtx_reg (rtx, rtx *, enum reg_class,
116
                          enum scan_actions, enum op_type);
117
static void scan_rtx_address (rtx, rtx *, enum reg_class,
118
                              enum scan_actions, enum machine_mode);
119
static void scan_rtx (rtx, rtx *, enum reg_class, enum scan_actions,
120
                      enum op_type);
121
static struct du_head *build_def_use (basic_block);
122
static void dump_def_use_chain (struct du_head *);
123
 
124
typedef struct du_head *du_head_p;
125
DEF_VEC_P (du_head_p);
126
DEF_VEC_ALLOC_P (du_head_p, heap);
127
static VEC(du_head_p, heap) *id_to_chain;
128
 
129
static void
130
free_chain_data (void)
131
{
132
  int i;
133
  du_head_p ptr;
134
  for (i = 0; VEC_iterate(du_head_p, id_to_chain, i, ptr); i++)
135
    bitmap_clear (&ptr->conflicts);
136
 
137
  VEC_free (du_head_p, heap, id_to_chain);
138
}
139
 
140
/* For a def-use chain HEAD, find which registers overlap its lifetime and
141
   set the corresponding bits in *PSET.  */
142
 
143
static void
144
merge_overlapping_regs (HARD_REG_SET *pset, struct du_head *head)
145
{
146
  bitmap_iterator bi;
147
  unsigned i;
148
  IOR_HARD_REG_SET (*pset, head->hard_conflicts);
149
  EXECUTE_IF_SET_IN_BITMAP (&head->conflicts, 0, i, bi)
150
    {
151
      du_head_p other = VEC_index (du_head_p, id_to_chain, i);
152
      unsigned j = other->nregs;
153
      while (j-- > 0)
154
        SET_HARD_REG_BIT (*pset, other->regno + j);
155
    }
156
}
157
 
158
/* Perform register renaming on the current function.  */
159
 
160
static unsigned int
161
regrename_optimize (void)
162
{
163
  int tick[FIRST_PSEUDO_REGISTER];
164
  int this_tick = 0;
165
  basic_block bb;
166
  char *first_obj;
167
 
168
  df_set_flags (DF_LR_RUN_DCE);
169
  df_note_add_problem ();
170
  df_analyze ();
171
  df_set_flags (DF_DEFER_INSN_RESCAN);
172
 
173
  memset (tick, 0, sizeof tick);
174
 
175
  gcc_obstack_init (&rename_obstack);
176
  first_obj = XOBNEWVAR (&rename_obstack, char, 0);
177
 
178
  FOR_EACH_BB (bb)
179
    {
180
      struct du_head *all_chains = 0;
181
      HARD_REG_SET unavailable;
182
#if 0
183
      HARD_REG_SET regs_seen;
184
      CLEAR_HARD_REG_SET (regs_seen);
185
#endif
186
 
187
      id_to_chain = VEC_alloc (du_head_p, heap, 0);
188
 
189
      CLEAR_HARD_REG_SET (unavailable);
190
 
191
      if (dump_file)
192
        fprintf (dump_file, "\nBasic block %d:\n", bb->index);
193
 
194
      all_chains = build_def_use (bb);
195
 
196
      if (dump_file)
197
        dump_def_use_chain (all_chains);
198
 
199
      CLEAR_HARD_REG_SET (unavailable);
200
      /* Don't clobber traceback for noreturn functions.  */
201
      if (frame_pointer_needed)
202
        {
203
          add_to_hard_reg_set (&unavailable, Pmode, FRAME_POINTER_REGNUM);
204
#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
205
          add_to_hard_reg_set (&unavailable, Pmode, HARD_FRAME_POINTER_REGNUM);
206
#endif
207
        }
208
 
209
      while (all_chains)
210
        {
211
          int new_reg, best_new_reg, best_nregs;
212
          int n_uses;
213
          struct du_head *this_head = all_chains;
214
          struct du_chain *tmp;
215
          HARD_REG_SET this_unavailable;
216
          int reg = this_head->regno;
217
          int i;
218
 
219
          all_chains = this_head->next_chain;
220
 
221
          if (this_head->cannot_rename)
222
            continue;
223
 
224
          best_new_reg = reg;
225
          best_nregs = this_head->nregs;
226
 
227
#if 0 /* This just disables optimization opportunities.  */
228
          /* Only rename once we've seen the reg more than once.  */
229
          if (! TEST_HARD_REG_BIT (regs_seen, reg))
230
            {
231
              SET_HARD_REG_BIT (regs_seen, reg);
232
              continue;
233
            }
234
#endif
235
 
236
          if (fixed_regs[reg] || global_regs[reg]
237
#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
238
              || (frame_pointer_needed && reg == HARD_FRAME_POINTER_REGNUM)
239
#else
240
              || (frame_pointer_needed && reg == FRAME_POINTER_REGNUM)
241
#endif
242
              )
243
            continue;
244
 
245
          COPY_HARD_REG_SET (this_unavailable, unavailable);
246
 
247
          /* Count number of uses, and narrow the set of registers we can
248
             use for renaming.  */
249
          n_uses = 0;
250
          for (tmp = this_head->first; tmp; tmp = tmp->next_use)
251
            {
252
              if (DEBUG_INSN_P (tmp->insn))
253
                continue;
254
              n_uses++;
255
              IOR_COMPL_HARD_REG_SET (this_unavailable,
256
                                      reg_class_contents[tmp->cl]);
257
            }
258
 
259
          if (n_uses < 2)
260
            continue;
261
 
262
          if (this_head->need_caller_save_reg)
263
            IOR_HARD_REG_SET (this_unavailable, call_used_reg_set);
264
 
265
          merge_overlapping_regs (&this_unavailable, this_head);
266
 
267
          /* Now potential_regs is a reasonable approximation, let's
268
             have a closer look at each register still in there.  */
269
          for (new_reg = 0; new_reg < FIRST_PSEUDO_REGISTER; new_reg++)
270
            {
271
              enum machine_mode mode = GET_MODE (*this_head->first->loc);
272
              int nregs = hard_regno_nregs[new_reg][mode];
273
 
274
              for (i = nregs - 1; i >= 0; --i)
275
                if (TEST_HARD_REG_BIT (this_unavailable, new_reg + i)
276
                    || fixed_regs[new_reg + i]
277
                    || global_regs[new_reg + i]
278
                    /* Can't use regs which aren't saved by the prologue.  */
279
                    || (! df_regs_ever_live_p (new_reg + i)
280
                        && ! call_used_regs[new_reg + i])
281
#ifdef LEAF_REGISTERS
282
                    /* We can't use a non-leaf register if we're in a
283
                       leaf function.  */
284
                    || (current_function_is_leaf
285
                        && !LEAF_REGISTERS[new_reg + i])
286
#endif
287
#ifdef HARD_REGNO_RENAME_OK
288
                    || ! HARD_REGNO_RENAME_OK (reg + i, new_reg + i)
289
#endif
290
                    )
291
                  break;
292
              if (i >= 0)
293
                continue;
294
 
295
              /* See whether it accepts all modes that occur in
296
                 definition and uses.  */
297
              for (tmp = this_head->first; tmp; tmp = tmp->next_use)
298
                if ((! HARD_REGNO_MODE_OK (new_reg, GET_MODE (*tmp->loc))
299
                     && ! DEBUG_INSN_P (tmp->insn))
300
                    || (this_head->need_caller_save_reg
301
                        && ! (HARD_REGNO_CALL_PART_CLOBBERED
302
                              (reg, GET_MODE (*tmp->loc)))
303
                        && (HARD_REGNO_CALL_PART_CLOBBERED
304
                            (new_reg, GET_MODE (*tmp->loc)))))
305
                  break;
306
              if (! tmp)
307
                {
308
                  if (tick[best_new_reg] > tick[new_reg])
309
                    {
310
                      best_new_reg = new_reg;
311
                      best_nregs = nregs;
312
                    }
313
                }
314
            }
315
 
316
          if (dump_file)
317
            {
318
              fprintf (dump_file, "Register %s in insn %d",
319
                       reg_names[reg], INSN_UID (this_head->first->insn));
320
              if (this_head->need_caller_save_reg)
321
                fprintf (dump_file, " crosses a call");
322
            }
323
 
324
          if (best_new_reg == reg)
325
            {
326
              tick[reg] = ++this_tick;
327
              if (dump_file)
328
                fprintf (dump_file, "; no available better choice\n");
329
              continue;
330
            }
331
 
332
          if (dump_file)
333
            fprintf (dump_file, ", renamed as %s\n", reg_names[best_new_reg]);
334
 
335
          do_replace (this_head, best_new_reg);
336
          this_head->regno = best_new_reg;
337
          this_head->nregs = best_nregs;
338
          tick[best_new_reg] = ++this_tick;
339
          df_set_regs_ever_live (best_new_reg, true);
340
        }
341
 
342
      free_chain_data ();
343
      obstack_free (&rename_obstack, first_obj);
344
    }
345
 
346
  obstack_free (&rename_obstack, NULL);
347
 
348
  if (dump_file)
349
    fputc ('\n', dump_file);
350
 
351
  return 0;
352
}
353
 
354
static void
355
do_replace (struct du_head *head, int reg)
356
{
357
  struct du_chain *chain;
358
  unsigned int base_regno = head->regno;
359
  bool found_note = false;
360
 
361
  gcc_assert (! DEBUG_INSN_P (head->first->insn));
362
 
363
  for (chain = head->first; chain; chain = chain->next_use)
364
    {
365
      unsigned int regno = ORIGINAL_REGNO (*chain->loc);
366
      struct reg_attrs *attr = REG_ATTRS (*chain->loc);
367
      int reg_ptr = REG_POINTER (*chain->loc);
368
 
369
      if (DEBUG_INSN_P (chain->insn) && REGNO (*chain->loc) != base_regno)
370
        INSN_VAR_LOCATION_LOC (chain->insn) = gen_rtx_UNKNOWN_VAR_LOC ();
371
      else
372
        {
373
          rtx note;
374
 
375
          *chain->loc = gen_raw_REG (GET_MODE (*chain->loc), reg);
376
          if (regno >= FIRST_PSEUDO_REGISTER)
377
            ORIGINAL_REGNO (*chain->loc) = regno;
378
          REG_ATTRS (*chain->loc) = attr;
379
          REG_POINTER (*chain->loc) = reg_ptr;
380
 
381
          for (note = REG_NOTES (chain->insn); note; note = XEXP (note, 1))
382
            {
383
              enum reg_note kind = REG_NOTE_KIND (note);
384
              if (kind == REG_DEAD || kind == REG_UNUSED)
385
                {
386
                  rtx reg = XEXP (note, 0);
387
                  gcc_assert (HARD_REGISTER_P (reg));
388
 
389
                  if (REGNO (reg) == base_regno)
390
                    {
391
                      found_note = true;
392
                      if (kind == REG_DEAD
393
                          && reg_set_p (*chain->loc, chain->insn))
394
                        remove_note (chain->insn, note);
395
                      else
396
                        XEXP (note, 0) = *chain->loc;
397
                      break;
398
                    }
399
                }
400
            }
401
        }
402
 
403
      df_insn_rescan (chain->insn);
404
    }
405
  if (!found_note)
406
    {
407
      /* If the chain's first insn is the same as the last, we should have
408
         found a REG_UNUSED note.  */
409
      gcc_assert (head->first->insn != head->last->insn);
410
      if (!reg_set_p (*head->last->loc, head->last->insn))
411
        add_reg_note (head->last->insn, REG_DEAD, *head->last->loc);
412
    }
413
}
414
 
415
 
416
/* Walk all chains starting with CHAINS and record that they conflict with
417
   another chain whose id is ID.  */
418
 
419
static void
420
mark_conflict (struct du_head *chains, unsigned id)
421
{
422
  while (chains)
423
    {
424
      bitmap_set_bit (&chains->conflicts, id);
425
      chains = chains->next_chain;
426
    }
427
}
428
 
429
/* True if we found a register with a size mismatch, which means that we
430
   can't track its lifetime accurately.  If so, we abort the current block
431
   without renaming.  */
432
static bool fail_current_block;
433
 
434
/* The id to be given to the next opened chain.  */
435
static unsigned current_id;
436
 
437
/* List of currently open chains, and closed chains that can be renamed.  */
438
static struct du_head *open_chains;
439
static struct du_head *closed_chains;
440
 
441
/* Bitmap of open chains.  The bits set always match the list found in
442
   open_chains.  */
443
static bitmap_head open_chains_set;
444
 
445
/* Record the registers being tracked in open_chains.  */
446
static HARD_REG_SET live_in_chains;
447
 
448
/* Record the registers that are live but not tracked.  The intersection
449
   between this and live_in_chains is empty.  */
450
static HARD_REG_SET live_hard_regs;
451
 
452
/* Return true if OP is a reg for which all bits are set in PSET, false
453
   if all bits are clear.
454
   In other cases, set fail_current_block and return false.  */
455
 
456
static bool
457
verify_reg_in_set (rtx op, HARD_REG_SET *pset)
458
{
459
  unsigned regno, nregs;
460
  bool all_live, all_dead;
461
  if (!REG_P (op))
462
    return false;
463
 
464
  regno = REGNO (op);
465
  nregs = hard_regno_nregs[regno][GET_MODE (op)];
466
  all_live = all_dead = true;
467
  while (nregs-- > 0)
468
    if (TEST_HARD_REG_BIT (*pset, regno + nregs))
469
      all_dead = false;
470
    else
471
      all_live = false;
472
  if (!all_dead && !all_live)
473
    {
474
      fail_current_block = true;
475
      return false;
476
    }
477
  return all_live;
478
}
479
 
480
/* Return true if OP is a reg that is being tracked already in some form.
481
   May set fail_current_block if it sees an unhandled case of overlap.  */
482
 
483
static bool
484
verify_reg_tracked (rtx op)
485
{
486
  return (verify_reg_in_set (op, &live_hard_regs)
487
          || verify_reg_in_set (op, &live_in_chains));
488
}
489
 
490
/* Called through note_stores.  DATA points to a rtx_code, either SET or
491
   CLOBBER, which tells us which kind of rtx to look at.  If we have a
492
   match, record the set register in live_hard_regs and in the hard_conflicts
493
   bitmap of open chains.  */
494
 
495
static void
496
note_sets_clobbers (rtx x, const_rtx set, void *data)
497
{
498
  enum rtx_code code = *(enum rtx_code *)data;
499
  struct du_head *chain;
500
 
501
  if (GET_CODE (x) == SUBREG)
502
    x = SUBREG_REG (x);
503
  if (!REG_P (x) || GET_CODE (set) != code)
504
    return;
505
  /* There must not be pseudos at this point.  */
506
  gcc_assert (HARD_REGISTER_P (x));
507
  add_to_hard_reg_set (&live_hard_regs, GET_MODE (x), REGNO (x));
508
  for (chain = open_chains; chain; chain = chain->next_chain)
509
    add_to_hard_reg_set (&chain->hard_conflicts, GET_MODE (x), REGNO (x));
510
}
511
 
512
/* Create a new chain for THIS_NREGS registers starting at THIS_REGNO,
513
   and record its occurrence in *LOC, which is being written to in INSN.
514
   This access requires a register of class CL.  */
515
 
516
static void
517
create_new_chain (unsigned this_regno, unsigned this_nregs, rtx *loc,
518
                  rtx insn, enum reg_class cl)
519
{
520
  struct du_head *head = XOBNEW (&rename_obstack, struct du_head);
521
  struct du_chain *this_du;
522
  int nregs;
523
 
524
  head->next_chain = open_chains;
525
  open_chains = head;
526
  head->regno = this_regno;
527
  head->nregs = this_nregs;
528
  head->need_caller_save_reg = 0;
529
  head->cannot_rename = 0;
530
  head->terminated = 0;
531
 
532
  VEC_safe_push (du_head_p, heap, id_to_chain, head);
533
  head->id = current_id++;
534
 
535
  bitmap_initialize (&head->conflicts, &bitmap_default_obstack);
536
  bitmap_copy (&head->conflicts, &open_chains_set);
537
  mark_conflict (open_chains, head->id);
538
 
539
  /* Since we're tracking this as a chain now, remove it from the
540
     list of conflicting live hard registers and track it in
541
     live_in_chains instead.  */
542
  nregs = head->nregs;
543
  while (nregs-- > 0)
544
    {
545
      SET_HARD_REG_BIT (live_in_chains, head->regno + nregs);
546
      CLEAR_HARD_REG_BIT (live_hard_regs, head->regno + nregs);
547
    }
548
 
549
  COPY_HARD_REG_SET (head->hard_conflicts, live_hard_regs);
550
  bitmap_set_bit (&open_chains_set, head->id);
551
 
552
  open_chains = head;
553
 
554
  if (dump_file)
555
    {
556
      fprintf (dump_file, "Creating chain %s (%d)",
557
               reg_names[head->regno], head->id);
558
      if (insn != NULL_RTX)
559
        fprintf (dump_file, " at insn %d", INSN_UID (insn));
560
      fprintf (dump_file, "\n");
561
    }
562
 
563
  if (insn == NULL_RTX)
564
    {
565
      head->first = head->last = NULL;
566
      return;
567
    }
568
 
569
  this_du = XOBNEW (&rename_obstack, struct du_chain);
570
  head->first = head->last = this_du;
571
 
572
  this_du->next_use = 0;
573
  this_du->loc = loc;
574
  this_du->insn = insn;
575
  this_du->cl = cl;
576
}
577
 
578
static void
579
scan_rtx_reg (rtx insn, rtx *loc, enum reg_class cl, enum scan_actions action,
580
              enum op_type type)
581
{
582
  struct du_head **p;
583
  rtx x = *loc;
584
  enum machine_mode mode = GET_MODE (x);
585
  unsigned this_regno = REGNO (x);
586
  unsigned this_nregs = hard_regno_nregs[this_regno][mode];
587
 
588
  if (action == mark_write)
589
    {
590
      if (type == OP_OUT)
591
        create_new_chain (this_regno, this_nregs, loc, insn, cl);
592
      return;
593
    }
594
 
595
  if ((type == OP_OUT) != (action == terminate_write || action == mark_access))
596
    return;
597
 
598
  for (p = &open_chains; *p;)
599
    {
600
      struct du_head *head = *p;
601
      struct du_head *next = head->next_chain;
602
      int exact_match = (head->regno == this_regno
603
                         && head->nregs == this_nregs);
604
      int superset = (this_regno <= head->regno
605
                      && this_regno + this_nregs >= head->regno + head->nregs);
606
      int subset = (this_regno >= head->regno
607
                      && this_regno + this_nregs <= head->regno + head->nregs);
608
 
609
      if (head->terminated
610
          || head->regno + head->nregs <= this_regno
611
          || this_regno + this_nregs <= head->regno)
612
        {
613
          p = &head->next_chain;
614
          continue;
615
        }
616
 
617
      if (action == mark_read || action == mark_access)
618
        {
619
          /* ??? Class NO_REGS can happen if the md file makes use of
620
             EXTRA_CONSTRAINTS to match registers.  Which is arguably
621
             wrong, but there we are.  */
622
 
623
          if (cl == NO_REGS || (!exact_match && !DEBUG_INSN_P (insn)))
624
            {
625
              if (dump_file)
626
                fprintf (dump_file,
627
                         "Cannot rename chain %s (%d) at insn %d (%s)\n",
628
                         reg_names[head->regno], head->id, INSN_UID (insn),
629
                         scan_actions_name[(int) action]);
630
              head->cannot_rename = 1;
631
              if (superset)
632
                {
633
                  unsigned nregs = this_nregs;
634
                  head->regno = this_regno;
635
                  head->nregs = this_nregs;
636
                  while (nregs-- > 0)
637
                    SET_HARD_REG_BIT (live_in_chains, head->regno + nregs);
638
                  if (dump_file)
639
                    fprintf (dump_file,
640
                             "Widening register in chain %s (%d) at insn %d\n",
641
                             reg_names[head->regno], head->id, INSN_UID (insn));
642
                }
643
              else if (!subset)
644
                {
645
                  fail_current_block = true;
646
                  if (dump_file)
647
                    fprintf (dump_file,
648
                             "Failing basic block due to unhandled overlap\n");
649
                }
650
            }
651
          else
652
            {
653
              struct du_chain *this_du;
654
              this_du = XOBNEW (&rename_obstack, struct du_chain);
655
              this_du->next_use = 0;
656
              this_du->loc = loc;
657
              this_du->insn = insn;
658
              this_du->cl = cl;
659
              if (head->first == NULL)
660
                head->first = this_du;
661
              else
662
                head->last->next_use = this_du;
663
              head->last = this_du;
664
 
665
            }
666
          /* Avoid adding the same location in a DEBUG_INSN multiple times,
667
             which could happen with non-exact overlap.  */
668
          if (DEBUG_INSN_P (insn))
669
            return;
670
          /* Otherwise, find any other chains that do not match exactly;
671
             ensure they all get marked unrenamable.  */
672
          p = &head->next_chain;
673
          continue;
674
        }
675
 
676
      /* Whether the terminated chain can be used for renaming
677
         depends on the action and this being an exact match.
678
         In either case, we remove this element from open_chains.  */
679
 
680
      if ((action == terminate_dead || action == terminate_write)
681
          && superset)
682
        {
683
          unsigned nregs;
684
 
685
          head->terminated = 1;
686
          head->next_chain = closed_chains;
687
          closed_chains = head;
688
          bitmap_clear_bit (&open_chains_set, head->id);
689
 
690
          nregs = head->nregs;
691
          while (nregs-- > 0)
692
            CLEAR_HARD_REG_BIT (live_in_chains, head->regno + nregs);
693
 
694
          *p = next;
695
          if (dump_file)
696
            fprintf (dump_file,
697
                     "Closing chain %s (%d) at insn %d (%s)\n",
698
                     reg_names[head->regno], head->id, INSN_UID (insn),
699
                     scan_actions_name[(int) action]);
700
        }
701
      else if (action == terminate_dead || action == terminate_write)
702
        {
703
          /* In this case, tracking liveness gets too hard.  Fail the
704
             entire basic block.  */
705
          if (dump_file)
706
            fprintf (dump_file,
707
                     "Failing basic block due to unhandled overlap\n");
708
          fail_current_block = true;
709
          return;
710
        }
711
      else
712
        {
713
          head->cannot_rename = 1;
714
          if (dump_file)
715
            fprintf (dump_file,
716
                     "Cannot rename chain %s (%d) at insn %d (%s)\n",
717
                     reg_names[head->regno], head->id, INSN_UID (insn),
718
                     scan_actions_name[(int) action]);
719
          p = &head->next_chain;
720
        }
721
    }
722
}
723
 
724
/* Adapted from find_reloads_address_1.  CL is INDEX_REG_CLASS or
725
   BASE_REG_CLASS depending on how the register is being considered.  */
726
 
727
static void
728
scan_rtx_address (rtx insn, rtx *loc, enum reg_class cl,
729
                  enum scan_actions action, enum machine_mode mode)
730
{
731
  rtx x = *loc;
732
  RTX_CODE code = GET_CODE (x);
733
  const char *fmt;
734
  int i, j;
735
 
736
  if (action == mark_write || action == mark_access)
737
    return;
738
 
739
  switch (code)
740
    {
741
    case PLUS:
742
      {
743
        rtx orig_op0 = XEXP (x, 0);
744
        rtx orig_op1 = XEXP (x, 1);
745
        RTX_CODE code0 = GET_CODE (orig_op0);
746
        RTX_CODE code1 = GET_CODE (orig_op1);
747
        rtx op0 = orig_op0;
748
        rtx op1 = orig_op1;
749
        rtx *locI = NULL;
750
        rtx *locB = NULL;
751
        enum rtx_code index_code = SCRATCH;
752
 
753
        if (GET_CODE (op0) == SUBREG)
754
          {
755
            op0 = SUBREG_REG (op0);
756
            code0 = GET_CODE (op0);
757
          }
758
 
759
        if (GET_CODE (op1) == SUBREG)
760
          {
761
            op1 = SUBREG_REG (op1);
762
            code1 = GET_CODE (op1);
763
          }
764
 
765
        if (code0 == MULT || code0 == SIGN_EXTEND || code0 == TRUNCATE
766
            || code0 == ZERO_EXTEND || code1 == MEM)
767
          {
768
            locI = &XEXP (x, 0);
769
            locB = &XEXP (x, 1);
770
            index_code = GET_CODE (*locI);
771
          }
772
        else if (code1 == MULT || code1 == SIGN_EXTEND || code1 == TRUNCATE
773
                 || code1 == ZERO_EXTEND || code0 == MEM)
774
          {
775
            locI = &XEXP (x, 1);
776
            locB = &XEXP (x, 0);
777
            index_code = GET_CODE (*locI);
778
          }
779
        else if (code0 == CONST_INT || code0 == CONST
780
                 || code0 == SYMBOL_REF || code0 == LABEL_REF)
781
          {
782
            locB = &XEXP (x, 1);
783
            index_code = GET_CODE (XEXP (x, 0));
784
          }
785
        else if (code1 == CONST_INT || code1 == CONST
786
                 || code1 == SYMBOL_REF || code1 == LABEL_REF)
787
          {
788
            locB = &XEXP (x, 0);
789
            index_code = GET_CODE (XEXP (x, 1));
790
          }
791
        else if (code0 == REG && code1 == REG)
792
          {
793
            int index_op;
794
            unsigned regno0 = REGNO (op0), regno1 = REGNO (op1);
795
 
796
            if (REGNO_OK_FOR_INDEX_P (regno1)
797
                && regno_ok_for_base_p (regno0, mode, PLUS, REG))
798
              index_op = 1;
799
            else if (REGNO_OK_FOR_INDEX_P (regno0)
800
                     && regno_ok_for_base_p (regno1, mode, PLUS, REG))
801
              index_op = 0;
802
            else if (regno_ok_for_base_p (regno0, mode, PLUS, REG)
803
                     || REGNO_OK_FOR_INDEX_P (regno1))
804
              index_op = 1;
805
            else if (regno_ok_for_base_p (regno1, mode, PLUS, REG))
806
              index_op = 0;
807
            else
808
              index_op = 1;
809
 
810
            locI = &XEXP (x, index_op);
811
            locB = &XEXP (x, !index_op);
812
            index_code = GET_CODE (*locI);
813
          }
814
        else if (code0 == REG)
815
          {
816
            locI = &XEXP (x, 0);
817
            locB = &XEXP (x, 1);
818
            index_code = GET_CODE (*locI);
819
          }
820
        else if (code1 == REG)
821
          {
822
            locI = &XEXP (x, 1);
823
            locB = &XEXP (x, 0);
824
            index_code = GET_CODE (*locI);
825
          }
826
 
827
        if (locI)
828
          scan_rtx_address (insn, locI, INDEX_REG_CLASS, action, mode);
829
        if (locB)
830
          scan_rtx_address (insn, locB, base_reg_class (mode, PLUS, index_code),
831
                            action, mode);
832
 
833
        return;
834
      }
835
 
836
    case POST_INC:
837
    case POST_DEC:
838
    case POST_MODIFY:
839
    case PRE_INC:
840
    case PRE_DEC:
841
    case PRE_MODIFY:
842
#ifndef AUTO_INC_DEC
843
      /* If the target doesn't claim to handle autoinc, this must be
844
         something special, like a stack push.  Kill this chain.  */
845
      action = mark_all_read;
846
#endif
847
      break;
848
 
849
    case MEM:
850
      scan_rtx_address (insn, &XEXP (x, 0),
851
                        base_reg_class (GET_MODE (x), MEM, SCRATCH), action,
852
                        GET_MODE (x));
853
      return;
854
 
855
    case REG:
856
      scan_rtx_reg (insn, loc, cl, action, OP_IN);
857
      return;
858
 
859
    default:
860
      break;
861
    }
862
 
863
  fmt = GET_RTX_FORMAT (code);
864
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
865
    {
866
      if (fmt[i] == 'e')
867
        scan_rtx_address (insn, &XEXP (x, i), cl, action, mode);
868
      else if (fmt[i] == 'E')
869
        for (j = XVECLEN (x, i) - 1; j >= 0; j--)
870
          scan_rtx_address (insn, &XVECEXP (x, i, j), cl, action, mode);
871
    }
872
}
873
 
874
static void
875
scan_rtx (rtx insn, rtx *loc, enum reg_class cl, enum scan_actions action,
876
          enum op_type type)
877
{
878
  const char *fmt;
879
  rtx x = *loc;
880
  enum rtx_code code = GET_CODE (x);
881
  int i, j;
882
 
883
  code = GET_CODE (x);
884
  switch (code)
885
    {
886
    case CONST:
887
    case CONST_INT:
888
    case CONST_DOUBLE:
889
    case CONST_FIXED:
890
    case CONST_VECTOR:
891
    case SYMBOL_REF:
892
    case LABEL_REF:
893
    case CC0:
894
    case PC:
895
      return;
896
 
897
    case REG:
898
      scan_rtx_reg (insn, loc, cl, action, type);
899
      return;
900
 
901
    case MEM:
902
      scan_rtx_address (insn, &XEXP (x, 0),
903
                        base_reg_class (GET_MODE (x), MEM, SCRATCH), action,
904
                        GET_MODE (x));
905
      return;
906
 
907
    case SET:
908
      scan_rtx (insn, &SET_SRC (x), cl, action, OP_IN);
909
      scan_rtx (insn, &SET_DEST (x), cl, action,
910
                (GET_CODE (PATTERN (insn)) == COND_EXEC
911
                 && verify_reg_tracked (SET_DEST (x))) ? OP_INOUT : OP_OUT);
912
      return;
913
 
914
    case STRICT_LOW_PART:
915
      scan_rtx (insn, &XEXP (x, 0), cl, action,
916
                verify_reg_tracked (XEXP (x, 0)) ? OP_INOUT : OP_OUT);
917
      return;
918
 
919
    case ZERO_EXTRACT:
920
    case SIGN_EXTRACT:
921
      scan_rtx (insn, &XEXP (x, 0), cl, action,
922
                (type == OP_IN ? OP_IN :
923
                 verify_reg_tracked (XEXP (x, 0)) ? OP_INOUT : OP_OUT));
924
      scan_rtx (insn, &XEXP (x, 1), cl, action, OP_IN);
925
      scan_rtx (insn, &XEXP (x, 2), cl, action, OP_IN);
926
      return;
927
 
928
    case POST_INC:
929
    case PRE_INC:
930
    case POST_DEC:
931
    case PRE_DEC:
932
    case POST_MODIFY:
933
    case PRE_MODIFY:
934
      /* Should only happen inside MEM.  */
935
      gcc_unreachable ();
936
 
937
    case CLOBBER:
938
      scan_rtx (insn, &SET_DEST (x), cl, action,
939
                (GET_CODE (PATTERN (insn)) == COND_EXEC
940
                 && verify_reg_tracked (SET_DEST (x))) ? OP_INOUT : OP_OUT);
941
      return;
942
 
943
    case EXPR_LIST:
944
      scan_rtx (insn, &XEXP (x, 0), cl, action, type);
945
      if (XEXP (x, 1))
946
        scan_rtx (insn, &XEXP (x, 1), cl, action, type);
947
      return;
948
 
949
    default:
950
      break;
951
    }
952
 
953
  fmt = GET_RTX_FORMAT (code);
954
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
955
    {
956
      if (fmt[i] == 'e')
957
        scan_rtx (insn, &XEXP (x, i), cl, action, type);
958
      else if (fmt[i] == 'E')
959
        for (j = XVECLEN (x, i) - 1; j >= 0; j--)
960
          scan_rtx (insn, &XVECEXP (x, i, j), cl, action, type);
961
    }
962
}
963
 
964
/* Hide operands of the current insn (of which there are N_OPS) by
965
   substituting cc0 for them.
966
   Previous values are stored in the OLD_OPERANDS and OLD_DUPS.
967
   For every bit set in DO_NOT_HIDE, we leave the operand alone.
968
   If INOUT_AND_EC_ONLY is set, we only do this for OP_INOUT type operands
969
   and earlyclobbers.  */
970
 
971
static void
972
hide_operands (int n_ops, rtx *old_operands, rtx *old_dups,
973
               unsigned HOST_WIDE_INT do_not_hide, bool inout_and_ec_only)
974
{
975
  int i;
976
  int alt = which_alternative;
977
  for (i = 0; i < n_ops; i++)
978
    {
979
      old_operands[i] = recog_data.operand[i];
980
      /* Don't squash match_operator or match_parallel here, since
981
         we don't know that all of the contained registers are
982
         reachable by proper operands.  */
983
      if (recog_data.constraints[i][0] == '\0')
984
        continue;
985
      if (do_not_hide & (1 << i))
986
        continue;
987
      if (!inout_and_ec_only || recog_data.operand_type[i] == OP_INOUT
988
          || recog_op_alt[i][alt].earlyclobber)
989
        *recog_data.operand_loc[i] = cc0_rtx;
990
    }
991
  for (i = 0; i < recog_data.n_dups; i++)
992
    {
993
      int opn = recog_data.dup_num[i];
994
      old_dups[i] = *recog_data.dup_loc[i];
995
      if (do_not_hide & (1 << opn))
996
        continue;
997
      if (!inout_and_ec_only || recog_data.operand_type[opn] == OP_INOUT
998
          || recog_op_alt[opn][alt].earlyclobber)
999
        *recog_data.dup_loc[i] = cc0_rtx;
1000
    }
1001
}
1002
 
1003
/* Undo the substitution performed by hide_operands.  INSN is the insn we
1004
   are processing; the arguments are the same as in hide_operands.  */
1005
 
1006
static void
1007
restore_operands (rtx insn, int n_ops, rtx *old_operands, rtx *old_dups)
1008
{
1009
  int i;
1010
  for (i = 0; i < recog_data.n_dups; i++)
1011
    *recog_data.dup_loc[i] = old_dups[i];
1012
  for (i = 0; i < n_ops; i++)
1013
    *recog_data.operand_loc[i] = old_operands[i];
1014
  if (recog_data.n_dups)
1015
    df_insn_rescan (insn);
1016
}
1017
 
1018
/* For each output operand of INSN, call scan_rtx to create a new
1019
   open chain.  Do this only for normal or earlyclobber outputs,
1020
   depending on EARLYCLOBBER.  */
1021
 
1022
static void
1023
record_out_operands (rtx insn, bool earlyclobber)
1024
{
1025
  int n_ops = recog_data.n_operands;
1026
  int alt = which_alternative;
1027
 
1028
  int i;
1029
 
1030
  for (i = 0; i < n_ops + recog_data.n_dups; i++)
1031
    {
1032
      int opn = i < n_ops ? i : recog_data.dup_num[i - n_ops];
1033
      rtx *loc = (i < n_ops
1034
                  ? recog_data.operand_loc[opn]
1035
                  : recog_data.dup_loc[i - n_ops]);
1036
      rtx op = *loc;
1037
      enum reg_class cl = recog_op_alt[opn][alt].cl;
1038
 
1039
      struct du_head *prev_open;
1040
 
1041
      if (recog_data.operand_type[opn] != OP_OUT
1042
          || recog_op_alt[opn][alt].earlyclobber != earlyclobber)
1043
        continue;
1044
 
1045
      prev_open = open_chains;
1046
      scan_rtx (insn, loc, cl, mark_write, OP_OUT);
1047
 
1048
      /* ??? Many targets have output constraints on the SET_DEST
1049
         of a call insn, which is stupid, since these are certainly
1050
         ABI defined hard registers.  For these, and for asm operands
1051
         that originally referenced hard registers, we must record that
1052
         the chain cannot be renamed.  */
1053
      if (CALL_P (insn)
1054
          || (asm_noperands (PATTERN (insn)) > 0
1055
              && REG_P (op)
1056
              && REGNO (op) == ORIGINAL_REGNO (op)))
1057
        {
1058
          if (prev_open != open_chains)
1059
            open_chains->cannot_rename = 1;
1060
        }
1061
    }
1062
}
1063
 
1064
/* Build def/use chain.  */
1065
 
1066
static struct du_head *
1067
build_def_use (basic_block bb)
1068
{
1069
  rtx insn;
1070
  df_ref *def_rec;
1071
  unsigned HOST_WIDE_INT untracked_operands;
1072
 
1073
  open_chains = closed_chains = NULL;
1074
 
1075
  fail_current_block = false;
1076
 
1077
  current_id = 0;
1078
  bitmap_initialize (&open_chains_set, &bitmap_default_obstack);
1079
  CLEAR_HARD_REG_SET (live_in_chains);
1080
  REG_SET_TO_HARD_REG_SET (live_hard_regs, df_get_live_in (bb));
1081
  for (def_rec = df_get_artificial_defs (bb->index); *def_rec; def_rec++)
1082
    {
1083
      df_ref def = *def_rec;
1084
      if (DF_REF_FLAGS (def) & DF_REF_AT_TOP)
1085
        SET_HARD_REG_BIT (live_hard_regs, DF_REF_REGNO (def));
1086
    }
1087
 
1088
  for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
1089
    {
1090
      if (NONDEBUG_INSN_P (insn))
1091
        {
1092
          int n_ops;
1093
          rtx note;
1094
          rtx old_operands[MAX_RECOG_OPERANDS];
1095
          rtx old_dups[MAX_DUP_OPERANDS];
1096
          int i;
1097
          int alt;
1098
          int predicated;
1099
          enum rtx_code set_code = SET;
1100
          enum rtx_code clobber_code = CLOBBER;
1101
 
1102
          /* Process the insn, determining its effect on the def-use
1103
             chains and live hard registers.  We perform the following
1104
             steps with the register references in the insn, simulating
1105
             its effect:
1106
             (1) Deal with earlyclobber operands and CLOBBERs of non-operands
1107
                 by creating chains and marking hard regs live.
1108
             (2) Any read outside an operand causes any chain it overlaps
1109
                 with to be marked unrenamable.
1110
             (3) Any read inside an operand is added if there's already
1111
                 an open chain for it.
1112
             (4) For any REG_DEAD note we find, close open chains that
1113
                 overlap it.
1114
             (5) For any non-earlyclobber write we find, close open chains
1115
                 that overlap it.
1116
             (6) For any non-earlyclobber write we find in an operand, make
1117
                 a new chain or mark the hard register as live.
1118
             (7) For any REG_UNUSED, close any chains we just opened.
1119
 
1120
             We cannot deal with situations where we track a reg in one mode
1121
             and see a reference in another mode; these will cause the chain
1122
             to be marked unrenamable or even cause us to abort the entire
1123
             basic block.  */
1124
 
1125
          extract_insn (insn);
1126
          if (! constrain_operands (1))
1127
            fatal_insn_not_found (insn);
1128
          preprocess_constraints ();
1129
          alt = which_alternative;
1130
          n_ops = recog_data.n_operands;
1131
          untracked_operands = 0;
1132
 
1133
          /* Simplify the code below by rewriting things to reflect
1134
             matching constraints.  Also promote OP_OUT to OP_INOUT in
1135
             predicated instructions, but only for register operands
1136
             that are already tracked, so that we can create a chain
1137
             when the first SET makes a register live.  */
1138
 
1139
          predicated = GET_CODE (PATTERN (insn)) == COND_EXEC;
1140
          for (i = 0; i < n_ops; ++i)
1141
            {
1142
              rtx op = recog_data.operand[i];
1143
              int matches = recog_op_alt[i][alt].matches;
1144
              if (matches >= 0)
1145
                recog_op_alt[i][alt].cl = recog_op_alt[matches][alt].cl;
1146
              if (matches >= 0 || recog_op_alt[i][alt].matched >= 0
1147
                  || (predicated && recog_data.operand_type[i] == OP_OUT))
1148
                {
1149
                  recog_data.operand_type[i] = OP_INOUT;
1150
                  /* A special case to deal with instruction patterns that
1151
                     have matching operands with different modes.  If we're
1152
                     not already tracking such a reg, we won't start here,
1153
                     and we must instead make sure to make the operand visible
1154
                     to the machinery that tracks hard registers.  */
1155
                  if (matches >= 0
1156
                      && (GET_MODE_SIZE (recog_data.operand_mode[i])
1157
                          != GET_MODE_SIZE (recog_data.operand_mode[matches]))
1158
                      && !verify_reg_in_set (op, &live_in_chains))
1159
                    {
1160
                      untracked_operands |= 1 << i;
1161
                      untracked_operands |= 1 << matches;
1162
                    }
1163
                }
1164
              /* If there's an in-out operand with a register that is not
1165
                 being tracked at all yet, open a chain.  */
1166
              if (recog_data.operand_type[i] == OP_INOUT
1167
                  && !(untracked_operands & (1 << i))
1168
                  && REG_P (op)
1169
                  && !verify_reg_tracked (op))
1170
                {
1171
                  enum machine_mode mode = GET_MODE (op);
1172
                  unsigned this_regno = REGNO (op);
1173
                  unsigned this_nregs = hard_regno_nregs[this_regno][mode];
1174
                  create_new_chain (this_regno, this_nregs, NULL, NULL_RTX,
1175
                                    NO_REGS);
1176
                }
1177
            }
1178
 
1179
          if (fail_current_block)
1180
            break;
1181
 
1182
          /* Step 1a: Mark hard registers that are clobbered in this insn,
1183
             outside an operand, as live.  */
1184
          hide_operands (n_ops, old_operands, old_dups, untracked_operands,
1185
                         false);
1186
          note_stores (PATTERN (insn), note_sets_clobbers, &clobber_code);
1187
          restore_operands (insn, n_ops, old_operands, old_dups);
1188
 
1189
          /* Step 1b: Begin new chains for earlyclobbered writes inside
1190
             operands.  */
1191
          record_out_operands (insn, true);
1192
 
1193
          /* Step 2: Mark chains for which we have reads outside operands
1194
             as unrenamable.
1195
             We do this by munging all operands into CC0, and closing
1196
             everything remaining.  */
1197
 
1198
          hide_operands (n_ops, old_operands, old_dups, untracked_operands,
1199
                         false);
1200
          scan_rtx (insn, &PATTERN (insn), NO_REGS, mark_all_read, OP_IN);
1201
          restore_operands (insn, n_ops, old_operands, old_dups);
1202
 
1203
          /* Step 2B: Can't rename function call argument registers.  */
1204
          if (CALL_P (insn) && CALL_INSN_FUNCTION_USAGE (insn))
1205
            scan_rtx (insn, &CALL_INSN_FUNCTION_USAGE (insn),
1206
                      NO_REGS, mark_all_read, OP_IN);
1207
 
1208
          /* Step 2C: Can't rename asm operands that were originally
1209
             hard registers.  */
1210
          if (asm_noperands (PATTERN (insn)) > 0)
1211
            for (i = 0; i < n_ops; i++)
1212
              {
1213
                rtx *loc = recog_data.operand_loc[i];
1214
                rtx op = *loc;
1215
 
1216
                if (REG_P (op)
1217
                    && REGNO (op) == ORIGINAL_REGNO (op)
1218
                    && (recog_data.operand_type[i] == OP_IN
1219
                        || recog_data.operand_type[i] == OP_INOUT))
1220
                  scan_rtx (insn, loc, NO_REGS, mark_all_read, OP_IN);
1221
              }
1222
 
1223
          /* Step 3: Append to chains for reads inside operands.  */
1224
          for (i = 0; i < n_ops + recog_data.n_dups; i++)
1225
            {
1226
              int opn = i < n_ops ? i : recog_data.dup_num[i - n_ops];
1227
              rtx *loc = (i < n_ops
1228
                          ? recog_data.operand_loc[opn]
1229
                          : recog_data.dup_loc[i - n_ops]);
1230
              enum reg_class cl = recog_op_alt[opn][alt].cl;
1231
              enum op_type type = recog_data.operand_type[opn];
1232
 
1233
              /* Don't scan match_operand here, since we've no reg class
1234
                 information to pass down.  Any operands that we could
1235
                 substitute in will be represented elsewhere.  */
1236
              if (recog_data.constraints[opn][0] == '\0'
1237
                  || untracked_operands & (1 << opn))
1238
                continue;
1239
 
1240
              if (recog_op_alt[opn][alt].is_address)
1241
                scan_rtx_address (insn, loc, cl, mark_read, VOIDmode);
1242
              else
1243
                scan_rtx (insn, loc, cl, mark_read, type);
1244
            }
1245
 
1246
          /* Step 3B: Record updates for regs in REG_INC notes, and
1247
             source regs in REG_FRAME_RELATED_EXPR notes.  */
1248
          for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1249
            if (REG_NOTE_KIND (note) == REG_INC
1250
                || REG_NOTE_KIND (note) == REG_FRAME_RELATED_EXPR)
1251
              scan_rtx (insn, &XEXP (note, 0), ALL_REGS, mark_read,
1252
                        OP_INOUT);
1253
 
1254
          /* Step 4: Close chains for registers that die here.  */
1255
          for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1256
            if (REG_NOTE_KIND (note) == REG_DEAD)
1257
              {
1258
                remove_from_hard_reg_set (&live_hard_regs,
1259
                                          GET_MODE (XEXP (note, 0)),
1260
                                          REGNO (XEXP (note, 0)));
1261
                scan_rtx (insn, &XEXP (note, 0), NO_REGS, terminate_dead,
1262
                          OP_IN);
1263
              }
1264
 
1265
          /* Step 4B: If this is a call, any chain live at this point
1266
             requires a caller-saved reg.  */
1267
          if (CALL_P (insn))
1268
            {
1269
              struct du_head *p;
1270
              for (p = open_chains; p; p = p->next_chain)
1271
                p->need_caller_save_reg = 1;
1272
            }
1273
 
1274
          /* Step 5: Close open chains that overlap writes.  Similar to
1275
             step 2, we hide in-out operands, since we do not want to
1276
             close these chains.  We also hide earlyclobber operands,
1277
             since we've opened chains for them in step 1, and earlier
1278
             chains they would overlap with must have been closed at
1279
             the previous insn at the latest, as such operands cannot
1280
             possibly overlap with any input operands.  */
1281
 
1282
          hide_operands (n_ops, old_operands, old_dups, untracked_operands,
1283
                         true);
1284
          scan_rtx (insn, &PATTERN (insn), NO_REGS, terminate_write, OP_IN);
1285
          restore_operands (insn, n_ops, old_operands, old_dups);
1286
 
1287
          /* Step 6a: Mark hard registers that are set in this insn,
1288
             outside an operand, as live.  */
1289
          hide_operands (n_ops, old_operands, old_dups, untracked_operands,
1290
                         false);
1291
          note_stores (PATTERN (insn), note_sets_clobbers, &set_code);
1292
          restore_operands (insn, n_ops, old_operands, old_dups);
1293
 
1294
          /* Step 6b: Begin new chains for writes inside operands.  */
1295
          record_out_operands (insn, false);
1296
 
1297
          /* Step 6c: Record destination regs in REG_FRAME_RELATED_EXPR
1298
             notes for update.  */
1299
          for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1300
            if (REG_NOTE_KIND (note) == REG_FRAME_RELATED_EXPR)
1301
              scan_rtx (insn, &XEXP (note, 0), ALL_REGS, mark_access,
1302
                        OP_INOUT);
1303
 
1304
          /* Step 7: Close chains for registers that were never
1305
             really used here.  */
1306
          for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1307
            if (REG_NOTE_KIND (note) == REG_UNUSED)
1308
              {
1309
                remove_from_hard_reg_set (&live_hard_regs,
1310
                                          GET_MODE (XEXP (note, 0)),
1311
                                          REGNO (XEXP (note, 0)));
1312
                scan_rtx (insn, &XEXP (note, 0), NO_REGS, terminate_dead,
1313
                          OP_IN);
1314
              }
1315
        }
1316
      else if (DEBUG_INSN_P (insn)
1317
               && !VAR_LOC_UNKNOWN_P (INSN_VAR_LOCATION_LOC (insn)))
1318
        {
1319
          scan_rtx (insn, &INSN_VAR_LOCATION_LOC (insn),
1320
                    ALL_REGS, mark_read, OP_IN);
1321
        }
1322
      if (insn == BB_END (bb))
1323
        break;
1324
    }
1325
 
1326
  bitmap_clear (&open_chains_set);
1327
 
1328
  if (fail_current_block)
1329
    return NULL;
1330
 
1331
  /* Since we close every chain when we find a REG_DEAD note, anything that
1332
     is still open lives past the basic block, so it can't be renamed.  */
1333
  return closed_chains;
1334
}
1335
 
1336
/* Dump all def/use chains in CHAINS to DUMP_FILE.  They are
1337
   printed in reverse order as that's how we build them.  */
1338
 
1339
static void
1340
dump_def_use_chain (struct du_head *head)
1341
{
1342
  while (head)
1343
    {
1344
      struct du_chain *this_du = head->first;
1345
      fprintf (dump_file, "Register %s (%d):",
1346
               reg_names[head->regno], head->nregs);
1347
      while (this_du)
1348
        {
1349
          fprintf (dump_file, " %d [%s]", INSN_UID (this_du->insn),
1350
                   reg_class_names[this_du->cl]);
1351
          this_du = this_du->next_use;
1352
        }
1353
      fprintf (dump_file, "\n");
1354
      head = head->next_chain;
1355
    }
1356
}
1357
 
1358
 
1359
static bool
1360
gate_handle_regrename (void)
1361
{
1362
  return (optimize > 0 && (flag_rename_registers));
1363
}
1364
 
1365
struct rtl_opt_pass pass_regrename =
1366
{
1367
 {
1368
  RTL_PASS,
1369
  "rnreg",                              /* name */
1370
  gate_handle_regrename,                /* gate */
1371
  regrename_optimize,                   /* execute */
1372
  NULL,                                 /* sub */
1373
  NULL,                                 /* next */
1374
  0,                                    /* static_pass_number */
1375
  TV_RENAME_REGISTERS,                  /* tv_id */
1376
  0,                                    /* properties_required */
1377
  0,                                    /* properties_provided */
1378
  0,                                    /* properties_destroyed */
1379
  0,                                    /* todo_flags_start */
1380
  TODO_df_finish | TODO_verify_rtl_sharing |
1381
  TODO_dump_func                        /* todo_flags_finish */
1382
 }
1383
};
1384
 

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