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

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1 280 jeremybenn
/* Copy propagation on hard registers 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
/* The following code does forward propagation of hard register copies.
44
   The object is to eliminate as many dependencies as possible, so that
45
   we have the most scheduling freedom.  As a side effect, we also clean
46
   up some silly register allocation decisions made by reload.  This
47
   code may be obsoleted by a new register allocator.  */
48
 
49
/* DEBUG_INSNs aren't changed right away, as doing so might extend the
50
   lifetime of a register and get the DEBUG_INSN subsequently reset.
51
   So they are queued instead, and updated only when the register is
52
   used in some subsequent real insn before it is set.  */
53
struct queued_debug_insn_change
54
{
55
  struct queued_debug_insn_change *next;
56
  rtx insn;
57
  rtx *loc;
58
  rtx new_rtx;
59
};
60
 
61
/* For each register, we have a list of registers that contain the same
62
   value.  The OLDEST_REGNO field points to the head of the list, and
63
   the NEXT_REGNO field runs through the list.  The MODE field indicates
64
   what mode the data is known to be in; this field is VOIDmode when the
65
   register is not known to contain valid data.  */
66
 
67
struct value_data_entry
68
{
69
  enum machine_mode mode;
70
  unsigned int oldest_regno;
71
  unsigned int next_regno;
72
  struct queued_debug_insn_change *debug_insn_changes;
73
};
74
 
75
struct value_data
76
{
77
  struct value_data_entry e[FIRST_PSEUDO_REGISTER];
78
  unsigned int max_value_regs;
79
  unsigned int n_debug_insn_changes;
80
};
81
 
82
static alloc_pool debug_insn_changes_pool;
83
 
84
static void kill_value_one_regno (unsigned, struct value_data *);
85
static void kill_value_regno (unsigned, unsigned, struct value_data *);
86
static void kill_value (rtx, struct value_data *);
87
static void set_value_regno (unsigned, enum machine_mode, struct value_data *);
88
static void init_value_data (struct value_data *);
89
static void kill_clobbered_value (rtx, const_rtx, void *);
90
static void kill_set_value (rtx, const_rtx, void *);
91
static int kill_autoinc_value (rtx *, void *);
92
static void copy_value (rtx, rtx, struct value_data *);
93
static bool mode_change_ok (enum machine_mode, enum machine_mode,
94
                            unsigned int);
95
static rtx maybe_mode_change (enum machine_mode, enum machine_mode,
96
                              enum machine_mode, unsigned int, unsigned int);
97
static rtx find_oldest_value_reg (enum reg_class, rtx, struct value_data *);
98
static bool replace_oldest_value_reg (rtx *, enum reg_class, rtx,
99
                                      struct value_data *);
100
static bool replace_oldest_value_addr (rtx *, enum reg_class,
101
                                       enum machine_mode, rtx,
102
                                       struct value_data *);
103
static bool replace_oldest_value_mem (rtx, rtx, struct value_data *);
104
static bool copyprop_hardreg_forward_1 (basic_block, struct value_data *);
105
extern void debug_value_data (struct value_data *);
106
#ifdef ENABLE_CHECKING
107
static void validate_value_data (struct value_data *);
108
#endif
109
 
110
/* Free all queued updates for DEBUG_INSNs that change some reg to
111
   register REGNO.  */
112
 
113
static void
114
free_debug_insn_changes (struct value_data *vd, unsigned int regno)
115
{
116
  struct queued_debug_insn_change *cur, *next;
117
  for (cur = vd->e[regno].debug_insn_changes; cur; cur = next)
118
    {
119
      next = cur->next;
120
      --vd->n_debug_insn_changes;
121
      pool_free (debug_insn_changes_pool, cur);
122
    }
123
  vd->e[regno].debug_insn_changes = NULL;
124
}
125
 
126
/* Kill register REGNO.  This involves removing it from any value
127
   lists, and resetting the value mode to VOIDmode.  This is only a
128
   helper function; it does not handle any hard registers overlapping
129
   with REGNO.  */
130
 
131
static void
132
kill_value_one_regno (unsigned int regno, struct value_data *vd)
133
{
134
  unsigned int i, next;
135
 
136
  if (vd->e[regno].oldest_regno != regno)
137
    {
138
      for (i = vd->e[regno].oldest_regno;
139
           vd->e[i].next_regno != regno;
140
           i = vd->e[i].next_regno)
141
        continue;
142
      vd->e[i].next_regno = vd->e[regno].next_regno;
143
    }
144
  else if ((next = vd->e[regno].next_regno) != INVALID_REGNUM)
145
    {
146
      for (i = next; i != INVALID_REGNUM; i = vd->e[i].next_regno)
147
        vd->e[i].oldest_regno = next;
148
    }
149
 
150
  vd->e[regno].mode = VOIDmode;
151
  vd->e[regno].oldest_regno = regno;
152
  vd->e[regno].next_regno = INVALID_REGNUM;
153
  if (vd->e[regno].debug_insn_changes)
154
    free_debug_insn_changes (vd, regno);
155
 
156
#ifdef ENABLE_CHECKING
157
  validate_value_data (vd);
158
#endif
159
}
160
 
161
/* Kill the value in register REGNO for NREGS, and any other registers
162
   whose values overlap.  */
163
 
164
static void
165
kill_value_regno (unsigned int regno, unsigned int nregs,
166
                  struct value_data *vd)
167
{
168
  unsigned int j;
169
 
170
  /* Kill the value we're told to kill.  */
171
  for (j = 0; j < nregs; ++j)
172
    kill_value_one_regno (regno + j, vd);
173
 
174
  /* Kill everything that overlapped what we're told to kill.  */
175
  if (regno < vd->max_value_regs)
176
    j = 0;
177
  else
178
    j = regno - vd->max_value_regs;
179
  for (; j < regno; ++j)
180
    {
181
      unsigned int i, n;
182
      if (vd->e[j].mode == VOIDmode)
183
        continue;
184
      n = hard_regno_nregs[j][vd->e[j].mode];
185
      if (j + n > regno)
186
        for (i = 0; i < n; ++i)
187
          kill_value_one_regno (j + i, vd);
188
    }
189
}
190
 
191
/* Kill X.  This is a convenience function wrapping kill_value_regno
192
   so that we mind the mode the register is in.  */
193
 
194
static void
195
kill_value (rtx x, struct value_data *vd)
196
{
197
  rtx orig_rtx = x;
198
 
199
  if (GET_CODE (x) == SUBREG)
200
    {
201
      x = simplify_subreg (GET_MODE (x), SUBREG_REG (x),
202
                           GET_MODE (SUBREG_REG (x)), SUBREG_BYTE (x));
203
      if (x == NULL_RTX)
204
        x = SUBREG_REG (orig_rtx);
205
    }
206
  if (REG_P (x))
207
    {
208
      unsigned int regno = REGNO (x);
209
      unsigned int n = hard_regno_nregs[regno][GET_MODE (x)];
210
 
211
      kill_value_regno (regno, n, vd);
212
    }
213
}
214
 
215
/* Remember that REGNO is valid in MODE.  */
216
 
217
static void
218
set_value_regno (unsigned int regno, enum machine_mode mode,
219
                 struct value_data *vd)
220
{
221
  unsigned int nregs;
222
 
223
  vd->e[regno].mode = mode;
224
 
225
  nregs = hard_regno_nregs[regno][mode];
226
  if (nregs > vd->max_value_regs)
227
    vd->max_value_regs = nregs;
228
}
229
 
230
/* Initialize VD such that there are no known relationships between regs.  */
231
 
232
static void
233
init_value_data (struct value_data *vd)
234
{
235
  int i;
236
  for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
237
    {
238
      vd->e[i].mode = VOIDmode;
239
      vd->e[i].oldest_regno = i;
240
      vd->e[i].next_regno = INVALID_REGNUM;
241
      vd->e[i].debug_insn_changes = NULL;
242
    }
243
  vd->max_value_regs = 0;
244
  vd->n_debug_insn_changes = 0;
245
}
246
 
247
/* Called through note_stores.  If X is clobbered, kill its value.  */
248
 
249
static void
250
kill_clobbered_value (rtx x, const_rtx set, void *data)
251
{
252
  struct value_data *const vd = (struct value_data *) data;
253
  if (GET_CODE (set) == CLOBBER)
254
    kill_value (x, vd);
255
}
256
 
257
/* Called through note_stores.  If X is set, not clobbered, kill its
258
   current value and install it as the root of its own value list.  */
259
 
260
static void
261
kill_set_value (rtx x, const_rtx set, void *data)
262
{
263
  struct value_data *const vd = (struct value_data *) data;
264
  if (GET_CODE (set) != CLOBBER)
265
    {
266
      kill_value (x, vd);
267
      if (REG_P (x))
268
        set_value_regno (REGNO (x), GET_MODE (x), vd);
269
    }
270
}
271
 
272
/* Called through for_each_rtx.  Kill any register used as the base of an
273
   auto-increment expression, and install that register as the root of its
274
   own value list.  */
275
 
276
static int
277
kill_autoinc_value (rtx *px, void *data)
278
{
279
  rtx x = *px;
280
  struct value_data *const vd = (struct value_data *) data;
281
 
282
  if (GET_RTX_CLASS (GET_CODE (x)) == RTX_AUTOINC)
283
    {
284
      x = XEXP (x, 0);
285
      kill_value (x, vd);
286
      set_value_regno (REGNO (x), GET_MODE (x), vd);
287
      return -1;
288
    }
289
 
290
  return 0;
291
}
292
 
293
/* Assert that SRC has been copied to DEST.  Adjust the data structures
294
   to reflect that SRC contains an older copy of the shared value.  */
295
 
296
static void
297
copy_value (rtx dest, rtx src, struct value_data *vd)
298
{
299
  unsigned int dr = REGNO (dest);
300
  unsigned int sr = REGNO (src);
301
  unsigned int dn, sn;
302
  unsigned int i;
303
 
304
  /* ??? At present, it's possible to see noop sets.  It'd be nice if
305
     this were cleaned up beforehand...  */
306
  if (sr == dr)
307
    return;
308
 
309
  /* Do not propagate copies to the stack pointer, as that can leave
310
     memory accesses with no scheduling dependency on the stack update.  */
311
  if (dr == STACK_POINTER_REGNUM)
312
    return;
313
 
314
  /* Likewise with the frame pointer, if we're using one.  */
315
  if (frame_pointer_needed && dr == HARD_FRAME_POINTER_REGNUM)
316
    return;
317
 
318
  /* Do not propagate copies to fixed or global registers, patterns
319
     can be relying to see particular fixed register or users can
320
     expect the chosen global register in asm.  */
321
  if (fixed_regs[dr] || global_regs[dr])
322
    return;
323
 
324
  /* If SRC and DEST overlap, don't record anything.  */
325
  dn = hard_regno_nregs[dr][GET_MODE (dest)];
326
  sn = hard_regno_nregs[sr][GET_MODE (dest)];
327
  if ((dr > sr && dr < sr + sn)
328
      || (sr > dr && sr < dr + dn))
329
    return;
330
 
331
  /* If SRC had no assigned mode (i.e. we didn't know it was live)
332
     assign it now and assume the value came from an input argument
333
     or somesuch.  */
334
  if (vd->e[sr].mode == VOIDmode)
335
    set_value_regno (sr, vd->e[dr].mode, vd);
336
 
337
  /* If we are narrowing the input to a smaller number of hard regs,
338
     and it is in big endian, we are really extracting a high part.
339
     Since we generally associate a low part of a value with the value itself,
340
     we must not do the same for the high part.
341
     Note we can still get low parts for the same mode combination through
342
     a two-step copy involving differently sized hard regs.
343
     Assume hard regs fr* are 32 bits bits each, while r* are 64 bits each:
344
     (set (reg:DI r0) (reg:DI fr0))
345
     (set (reg:SI fr2) (reg:SI r0))
346
     loads the low part of (reg:DI fr0) - i.e. fr1 - into fr2, while:
347
     (set (reg:SI fr2) (reg:SI fr0))
348
     loads the high part of (reg:DI fr0) into fr2.
349
 
350
     We can't properly represent the latter case in our tables, so don't
351
     record anything then.  */
352
  else if (sn < (unsigned int) hard_regno_nregs[sr][vd->e[sr].mode]
353
           && (GET_MODE_SIZE (vd->e[sr].mode) > UNITS_PER_WORD
354
               ? WORDS_BIG_ENDIAN : BYTES_BIG_ENDIAN))
355
    return;
356
 
357
  /* If SRC had been assigned a mode narrower than the copy, we can't
358
     link DEST into the chain, because not all of the pieces of the
359
     copy came from oldest_regno.  */
360
  else if (sn > (unsigned int) hard_regno_nregs[sr][vd->e[sr].mode])
361
    return;
362
 
363
  /* Link DR at the end of the value chain used by SR.  */
364
 
365
  vd->e[dr].oldest_regno = vd->e[sr].oldest_regno;
366
 
367
  for (i = sr; vd->e[i].next_regno != INVALID_REGNUM; i = vd->e[i].next_regno)
368
    continue;
369
  vd->e[i].next_regno = dr;
370
 
371
#ifdef ENABLE_CHECKING
372
  validate_value_data (vd);
373
#endif
374
}
375
 
376
/* Return true if a mode change from ORIG to NEW is allowed for REGNO.  */
377
 
378
static bool
379
mode_change_ok (enum machine_mode orig_mode, enum machine_mode new_mode,
380
                unsigned int regno ATTRIBUTE_UNUSED)
381
{
382
  if (GET_MODE_SIZE (orig_mode) < GET_MODE_SIZE (new_mode))
383
    return false;
384
 
385
#ifdef CANNOT_CHANGE_MODE_CLASS
386
  return !REG_CANNOT_CHANGE_MODE_P (regno, orig_mode, new_mode);
387
#endif
388
 
389
  return true;
390
}
391
 
392
/* Register REGNO was originally set in ORIG_MODE.  It - or a copy of it -
393
   was copied in COPY_MODE to COPY_REGNO, and then COPY_REGNO was accessed
394
   in NEW_MODE.
395
   Return a NEW_MODE rtx for REGNO if that's OK, otherwise return NULL_RTX.  */
396
 
397
static rtx
398
maybe_mode_change (enum machine_mode orig_mode, enum machine_mode copy_mode,
399
                   enum machine_mode new_mode, unsigned int regno,
400
                   unsigned int copy_regno ATTRIBUTE_UNUSED)
401
{
402
  if (GET_MODE_SIZE (copy_mode) < GET_MODE_SIZE (orig_mode)
403
      && GET_MODE_SIZE (copy_mode) < GET_MODE_SIZE (new_mode))
404
    return NULL_RTX;
405
 
406
  if (orig_mode == new_mode)
407
    return gen_rtx_raw_REG (new_mode, regno);
408
  else if (mode_change_ok (orig_mode, new_mode, regno))
409
    {
410
      int copy_nregs = hard_regno_nregs[copy_regno][copy_mode];
411
      int use_nregs = hard_regno_nregs[copy_regno][new_mode];
412
      int copy_offset
413
        = GET_MODE_SIZE (copy_mode) / copy_nregs * (copy_nregs - use_nregs);
414
      int offset
415
        = GET_MODE_SIZE (orig_mode) - GET_MODE_SIZE (new_mode) - copy_offset;
416
      int byteoffset = offset % UNITS_PER_WORD;
417
      int wordoffset = offset - byteoffset;
418
 
419
      offset = ((WORDS_BIG_ENDIAN ? wordoffset : 0)
420
                + (BYTES_BIG_ENDIAN ? byteoffset : 0));
421
      return gen_rtx_raw_REG (new_mode,
422
                              regno + subreg_regno_offset (regno, orig_mode,
423
                                                           offset,
424
                                                           new_mode));
425
    }
426
  return NULL_RTX;
427
}
428
 
429
/* Find the oldest copy of the value contained in REGNO that is in
430
   register class CL and has mode MODE.  If found, return an rtx
431
   of that oldest register, otherwise return NULL.  */
432
 
433
static rtx
434
find_oldest_value_reg (enum reg_class cl, rtx reg, struct value_data *vd)
435
{
436
  unsigned int regno = REGNO (reg);
437
  enum machine_mode mode = GET_MODE (reg);
438
  unsigned int i;
439
 
440
  /* If we are accessing REG in some mode other that what we set it in,
441
     make sure that the replacement is valid.  In particular, consider
442
        (set (reg:DI r11) (...))
443
        (set (reg:SI r9) (reg:SI r11))
444
        (set (reg:SI r10) (...))
445
        (set (...) (reg:DI r9))
446
     Replacing r9 with r11 is invalid.  */
447
  if (mode != vd->e[regno].mode)
448
    {
449
      if (hard_regno_nregs[regno][mode]
450
          > hard_regno_nregs[regno][vd->e[regno].mode])
451
        return NULL_RTX;
452
    }
453
 
454
  for (i = vd->e[regno].oldest_regno; i != regno; i = vd->e[i].next_regno)
455
    {
456
      enum machine_mode oldmode = vd->e[i].mode;
457
      rtx new_rtx;
458
 
459
      if (!in_hard_reg_set_p (reg_class_contents[cl], mode, i))
460
        return NULL_RTX;
461
 
462
      new_rtx = maybe_mode_change (oldmode, vd->e[regno].mode, mode, i, regno);
463
      if (new_rtx)
464
        {
465
          ORIGINAL_REGNO (new_rtx) = ORIGINAL_REGNO (reg);
466
          REG_ATTRS (new_rtx) = REG_ATTRS (reg);
467
          REG_POINTER (new_rtx) = REG_POINTER (reg);
468
          return new_rtx;
469
        }
470
    }
471
 
472
  return NULL_RTX;
473
}
474
 
475
/* If possible, replace the register at *LOC with the oldest register
476
   in register class CL.  Return true if successfully replaced.  */
477
 
478
static bool
479
replace_oldest_value_reg (rtx *loc, enum reg_class cl, rtx insn,
480
                          struct value_data *vd)
481
{
482
  rtx new_rtx = find_oldest_value_reg (cl, *loc, vd);
483
  if (new_rtx)
484
    {
485
      if (DEBUG_INSN_P (insn))
486
        {
487
          struct queued_debug_insn_change *change;
488
 
489
          if (dump_file)
490
            fprintf (dump_file, "debug_insn %u: queued replacing reg %u with %u\n",
491
                     INSN_UID (insn), REGNO (*loc), REGNO (new_rtx));
492
 
493
          change = (struct queued_debug_insn_change *)
494
                   pool_alloc (debug_insn_changes_pool);
495
          change->next = vd->e[REGNO (new_rtx)].debug_insn_changes;
496
          change->insn = insn;
497
          change->loc = loc;
498
          change->new_rtx = new_rtx;
499
          vd->e[REGNO (new_rtx)].debug_insn_changes = change;
500
          ++vd->n_debug_insn_changes;
501
          return true;
502
        }
503
      if (dump_file)
504
        fprintf (dump_file, "insn %u: replaced reg %u with %u\n",
505
                 INSN_UID (insn), REGNO (*loc), REGNO (new_rtx));
506
 
507
      validate_change (insn, loc, new_rtx, 1);
508
      return true;
509
    }
510
  return false;
511
}
512
 
513
/* Similar to replace_oldest_value_reg, but *LOC contains an address.
514
   Adapted from find_reloads_address_1.  CL is INDEX_REG_CLASS or
515
   BASE_REG_CLASS depending on how the register is being considered.  */
516
 
517
static bool
518
replace_oldest_value_addr (rtx *loc, enum reg_class cl,
519
                           enum machine_mode mode, rtx insn,
520
                           struct value_data *vd)
521
{
522
  rtx x = *loc;
523
  RTX_CODE code = GET_CODE (x);
524
  const char *fmt;
525
  int i, j;
526
  bool changed = false;
527
 
528
  switch (code)
529
    {
530
    case PLUS:
531
      if (DEBUG_INSN_P (insn))
532
        break;
533
 
534
      {
535
        rtx orig_op0 = XEXP (x, 0);
536
        rtx orig_op1 = XEXP (x, 1);
537
        RTX_CODE code0 = GET_CODE (orig_op0);
538
        RTX_CODE code1 = GET_CODE (orig_op1);
539
        rtx op0 = orig_op0;
540
        rtx op1 = orig_op1;
541
        rtx *locI = NULL;
542
        rtx *locB = NULL;
543
        enum rtx_code index_code = SCRATCH;
544
 
545
        if (GET_CODE (op0) == SUBREG)
546
          {
547
            op0 = SUBREG_REG (op0);
548
            code0 = GET_CODE (op0);
549
          }
550
 
551
        if (GET_CODE (op1) == SUBREG)
552
          {
553
            op1 = SUBREG_REG (op1);
554
            code1 = GET_CODE (op1);
555
          }
556
 
557
        if (code0 == MULT || code0 == SIGN_EXTEND || code0 == TRUNCATE
558
            || code0 == ZERO_EXTEND || code1 == MEM)
559
          {
560
            locI = &XEXP (x, 0);
561
            locB = &XEXP (x, 1);
562
            index_code = GET_CODE (*locI);
563
          }
564
        else if (code1 == MULT || code1 == SIGN_EXTEND || code1 == TRUNCATE
565
                 || code1 == ZERO_EXTEND || code0 == MEM)
566
          {
567
            locI = &XEXP (x, 1);
568
            locB = &XEXP (x, 0);
569
            index_code = GET_CODE (*locI);
570
          }
571
        else if (code0 == CONST_INT || code0 == CONST
572
                 || code0 == SYMBOL_REF || code0 == LABEL_REF)
573
          {
574
            locB = &XEXP (x, 1);
575
            index_code = GET_CODE (XEXP (x, 0));
576
          }
577
        else if (code1 == CONST_INT || code1 == CONST
578
                 || code1 == SYMBOL_REF || code1 == LABEL_REF)
579
          {
580
            locB = &XEXP (x, 0);
581
            index_code = GET_CODE (XEXP (x, 1));
582
          }
583
        else if (code0 == REG && code1 == REG)
584
          {
585
            int index_op;
586
            unsigned regno0 = REGNO (op0), regno1 = REGNO (op1);
587
 
588
            if (REGNO_OK_FOR_INDEX_P (regno1)
589
                && regno_ok_for_base_p (regno0, mode, PLUS, REG))
590
              index_op = 1;
591
            else if (REGNO_OK_FOR_INDEX_P (regno0)
592
                     && regno_ok_for_base_p (regno1, mode, PLUS, REG))
593
              index_op = 0;
594
            else if (regno_ok_for_base_p (regno0, mode, PLUS, REG)
595
                     || REGNO_OK_FOR_INDEX_P (regno1))
596
              index_op = 1;
597
            else if (regno_ok_for_base_p (regno1, mode, PLUS, REG))
598
              index_op = 0;
599
            else
600
              index_op = 1;
601
 
602
            locI = &XEXP (x, index_op);
603
            locB = &XEXP (x, !index_op);
604
            index_code = GET_CODE (*locI);
605
          }
606
        else if (code0 == REG)
607
          {
608
            locI = &XEXP (x, 0);
609
            locB = &XEXP (x, 1);
610
            index_code = GET_CODE (*locI);
611
          }
612
        else if (code1 == REG)
613
          {
614
            locI = &XEXP (x, 1);
615
            locB = &XEXP (x, 0);
616
            index_code = GET_CODE (*locI);
617
          }
618
 
619
        if (locI)
620
          changed |= replace_oldest_value_addr (locI, INDEX_REG_CLASS, mode,
621
                                                insn, vd);
622
        if (locB)
623
          changed |= replace_oldest_value_addr (locB,
624
                                                base_reg_class (mode, PLUS,
625
                                                                index_code),
626
                                                mode, insn, vd);
627
        return changed;
628
      }
629
 
630
    case POST_INC:
631
    case POST_DEC:
632
    case POST_MODIFY:
633
    case PRE_INC:
634
    case PRE_DEC:
635
    case PRE_MODIFY:
636
      return false;
637
 
638
    case MEM:
639
      return replace_oldest_value_mem (x, insn, vd);
640
 
641
    case REG:
642
      return replace_oldest_value_reg (loc, cl, insn, vd);
643
 
644
    default:
645
      break;
646
    }
647
 
648
  fmt = GET_RTX_FORMAT (code);
649
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
650
    {
651
      if (fmt[i] == 'e')
652
        changed |= replace_oldest_value_addr (&XEXP (x, i), cl, mode,
653
                                              insn, vd);
654
      else if (fmt[i] == 'E')
655
        for (j = XVECLEN (x, i) - 1; j >= 0; j--)
656
          changed |= replace_oldest_value_addr (&XVECEXP (x, i, j), cl,
657
                                                mode, insn, vd);
658
    }
659
 
660
  return changed;
661
}
662
 
663
/* Similar to replace_oldest_value_reg, but X contains a memory.  */
664
 
665
static bool
666
replace_oldest_value_mem (rtx x, rtx insn, struct value_data *vd)
667
{
668
  enum reg_class cl;
669
 
670
  if (DEBUG_INSN_P (insn))
671
    cl = ALL_REGS;
672
  else
673
    cl = base_reg_class (GET_MODE (x), MEM, SCRATCH);
674
 
675
  return replace_oldest_value_addr (&XEXP (x, 0), cl,
676
                                    GET_MODE (x), insn, vd);
677
}
678
 
679
/* Apply all queued updates for DEBUG_INSNs that change some reg to
680
   register REGNO.  */
681
 
682
static void
683
apply_debug_insn_changes (struct value_data *vd, unsigned int regno)
684
{
685
  struct queued_debug_insn_change *change;
686
  rtx last_insn = vd->e[regno].debug_insn_changes->insn;
687
 
688
  for (change = vd->e[regno].debug_insn_changes;
689
       change;
690
       change = change->next)
691
    {
692
      if (last_insn != change->insn)
693
        {
694
          apply_change_group ();
695
          last_insn = change->insn;
696
        }
697
      validate_change (change->insn, change->loc, change->new_rtx, 1);
698
    }
699
  apply_change_group ();
700
}
701
 
702
/* Called via for_each_rtx, for all used registers in a real
703
   insn apply DEBUG_INSN changes that change registers to the
704
   used register.  */
705
 
706
static int
707
cprop_find_used_regs_1 (rtx *loc, void *data)
708
{
709
  if (REG_P (*loc))
710
    {
711
      struct value_data *vd = (struct value_data *) data;
712
      if (vd->e[REGNO (*loc)].debug_insn_changes)
713
        {
714
          apply_debug_insn_changes (vd, REGNO (*loc));
715
          free_debug_insn_changes (vd, REGNO (*loc));
716
        }
717
    }
718
  return 0;
719
}
720
 
721
/* Called via note_uses, for all used registers in a real insn
722
   apply DEBUG_INSN changes that change registers to the used
723
   registers.  */
724
 
725
static void
726
cprop_find_used_regs (rtx *loc, void *vd)
727
{
728
  for_each_rtx (loc, cprop_find_used_regs_1, vd);
729
}
730
 
731
/* Perform the forward copy propagation on basic block BB.  */
732
 
733
static bool
734
copyprop_hardreg_forward_1 (basic_block bb, struct value_data *vd)
735
{
736
  bool anything_changed = false;
737
  rtx insn;
738
 
739
  for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
740
    {
741
      int n_ops, i, alt, predicated;
742
      bool is_asm, any_replacements;
743
      rtx set;
744
      bool replaced[MAX_RECOG_OPERANDS];
745
      bool changed = false;
746
 
747
      if (!NONDEBUG_INSN_P (insn))
748
        {
749
          if (DEBUG_INSN_P (insn))
750
            {
751
              rtx loc = INSN_VAR_LOCATION_LOC (insn);
752
              if (!VAR_LOC_UNKNOWN_P (loc))
753
                replace_oldest_value_addr (&INSN_VAR_LOCATION_LOC (insn),
754
                                           ALL_REGS, GET_MODE (loc),
755
                                           insn, vd);
756
            }
757
 
758
          if (insn == BB_END (bb))
759
            break;
760
          else
761
            continue;
762
        }
763
 
764
      set = single_set (insn);
765
      extract_insn (insn);
766
      if (! constrain_operands (1))
767
        fatal_insn_not_found (insn);
768
      preprocess_constraints ();
769
      alt = which_alternative;
770
      n_ops = recog_data.n_operands;
771
      is_asm = asm_noperands (PATTERN (insn)) >= 0;
772
 
773
      /* Simplify the code below by rewriting things to reflect
774
         matching constraints.  Also promote OP_OUT to OP_INOUT
775
         in predicated instructions.  */
776
 
777
      predicated = GET_CODE (PATTERN (insn)) == COND_EXEC;
778
      for (i = 0; i < n_ops; ++i)
779
        {
780
          int matches = recog_op_alt[i][alt].matches;
781
          if (matches >= 0)
782
            recog_op_alt[i][alt].cl = recog_op_alt[matches][alt].cl;
783
          if (matches >= 0 || recog_op_alt[i][alt].matched >= 0
784
              || (predicated && recog_data.operand_type[i] == OP_OUT))
785
            recog_data.operand_type[i] = OP_INOUT;
786
        }
787
 
788
      /* Apply changes to earlier DEBUG_INSNs if possible.  */
789
      if (vd->n_debug_insn_changes)
790
        note_uses (&PATTERN (insn), cprop_find_used_regs, vd);
791
 
792
      /* For each earlyclobber operand, zap the value data.  */
793
      for (i = 0; i < n_ops; i++)
794
        if (recog_op_alt[i][alt].earlyclobber)
795
          kill_value (recog_data.operand[i], vd);
796
 
797
      /* Within asms, a clobber cannot overlap inputs or outputs.
798
         I wouldn't think this were true for regular insns, but
799
         scan_rtx treats them like that...  */
800
      note_stores (PATTERN (insn), kill_clobbered_value, vd);
801
 
802
      /* Kill all auto-incremented values.  */
803
      /* ??? REG_INC is useless, since stack pushes aren't done that way.  */
804
      for_each_rtx (&PATTERN (insn), kill_autoinc_value, vd);
805
 
806
      /* Kill all early-clobbered operands.  */
807
      for (i = 0; i < n_ops; i++)
808
        if (recog_op_alt[i][alt].earlyclobber)
809
          kill_value (recog_data.operand[i], vd);
810
 
811
      /* Special-case plain move instructions, since we may well
812
         be able to do the move from a different register class.  */
813
      if (set && REG_P (SET_SRC (set)))
814
        {
815
          rtx src = SET_SRC (set);
816
          unsigned int regno = REGNO (src);
817
          enum machine_mode mode = GET_MODE (src);
818
          unsigned int i;
819
          rtx new_rtx;
820
 
821
          /* If we are accessing SRC in some mode other that what we
822
             set it in, make sure that the replacement is valid.  */
823
          if (mode != vd->e[regno].mode)
824
            {
825
              if (hard_regno_nregs[regno][mode]
826
                  > hard_regno_nregs[regno][vd->e[regno].mode])
827
                goto no_move_special_case;
828
            }
829
 
830
          /* If the destination is also a register, try to find a source
831
             register in the same class.  */
832
          if (REG_P (SET_DEST (set)))
833
            {
834
              new_rtx = find_oldest_value_reg (REGNO_REG_CLASS (regno), src, vd);
835
              if (new_rtx && validate_change (insn, &SET_SRC (set), new_rtx, 0))
836
                {
837
                  if (dump_file)
838
                    fprintf (dump_file,
839
                             "insn %u: replaced reg %u with %u\n",
840
                             INSN_UID (insn), regno, REGNO (new_rtx));
841
                  changed = true;
842
                  goto did_replacement;
843
                }
844
            }
845
 
846
          /* Otherwise, try all valid registers and see if its valid.  */
847
          for (i = vd->e[regno].oldest_regno; i != regno;
848
               i = vd->e[i].next_regno)
849
            {
850
              new_rtx = maybe_mode_change (vd->e[i].mode, vd->e[regno].mode,
851
                                       mode, i, regno);
852
              if (new_rtx != NULL_RTX)
853
                {
854
                  if (validate_change (insn, &SET_SRC (set), new_rtx, 0))
855
                    {
856
                      ORIGINAL_REGNO (new_rtx) = ORIGINAL_REGNO (src);
857
                      REG_ATTRS (new_rtx) = REG_ATTRS (src);
858
                      REG_POINTER (new_rtx) = REG_POINTER (src);
859
                      if (dump_file)
860
                        fprintf (dump_file,
861
                                 "insn %u: replaced reg %u with %u\n",
862
                                 INSN_UID (insn), regno, REGNO (new_rtx));
863
                      changed = true;
864
                      goto did_replacement;
865
                    }
866
                }
867
            }
868
        }
869
      no_move_special_case:
870
 
871
      any_replacements = false;
872
 
873
      /* For each input operand, replace a hard register with the
874
         eldest live copy that's in an appropriate register class.  */
875
      for (i = 0; i < n_ops; i++)
876
        {
877
          replaced[i] = false;
878
 
879
          /* Don't scan match_operand here, since we've no reg class
880
             information to pass down.  Any operands that we could
881
             substitute in will be represented elsewhere.  */
882
          if (recog_data.constraints[i][0] == '\0')
883
            continue;
884
 
885
          /* Don't replace in asms intentionally referencing hard regs.  */
886
          if (is_asm && REG_P (recog_data.operand[i])
887
              && (REGNO (recog_data.operand[i])
888
                  == ORIGINAL_REGNO (recog_data.operand[i])))
889
            continue;
890
 
891
          if (recog_data.operand_type[i] == OP_IN)
892
            {
893
              if (recog_op_alt[i][alt].is_address)
894
                replaced[i]
895
                  = replace_oldest_value_addr (recog_data.operand_loc[i],
896
                                               recog_op_alt[i][alt].cl,
897
                                               VOIDmode, insn, vd);
898
              else if (REG_P (recog_data.operand[i]))
899
                replaced[i]
900
                  = replace_oldest_value_reg (recog_data.operand_loc[i],
901
                                              recog_op_alt[i][alt].cl,
902
                                              insn, vd);
903
              else if (MEM_P (recog_data.operand[i]))
904
                replaced[i] = replace_oldest_value_mem (recog_data.operand[i],
905
                                                        insn, vd);
906
            }
907
          else if (MEM_P (recog_data.operand[i]))
908
            replaced[i] = replace_oldest_value_mem (recog_data.operand[i],
909
                                                    insn, vd);
910
 
911
          /* If we performed any replacement, update match_dups.  */
912
          if (replaced[i])
913
            {
914
              int j;
915
              rtx new_rtx;
916
 
917
              new_rtx = *recog_data.operand_loc[i];
918
              recog_data.operand[i] = new_rtx;
919
              for (j = 0; j < recog_data.n_dups; j++)
920
                if (recog_data.dup_num[j] == i)
921
                  validate_unshare_change (insn, recog_data.dup_loc[j], new_rtx, 1);
922
 
923
              any_replacements = true;
924
            }
925
        }
926
 
927
      if (any_replacements)
928
        {
929
          if (! apply_change_group ())
930
            {
931
              for (i = 0; i < n_ops; i++)
932
                if (replaced[i])
933
                  {
934
                    rtx old = *recog_data.operand_loc[i];
935
                    recog_data.operand[i] = old;
936
                  }
937
 
938
              if (dump_file)
939
                fprintf (dump_file,
940
                         "insn %u: reg replacements not verified\n",
941
                         INSN_UID (insn));
942
            }
943
          else
944
            changed = true;
945
        }
946
 
947
    did_replacement:
948
      if (changed)
949
        anything_changed = true;
950
 
951
      /* Clobber call-clobbered registers.  */
952
      if (CALL_P (insn))
953
        for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
954
          if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
955
            kill_value_regno (i, 1, vd);
956
 
957
      /* Notice stores.  */
958
      note_stores (PATTERN (insn), kill_set_value, vd);
959
 
960
      /* Notice copies.  */
961
      if (set && REG_P (SET_DEST (set)) && REG_P (SET_SRC (set)))
962
        copy_value (SET_DEST (set), SET_SRC (set), vd);
963
 
964
      if (insn == BB_END (bb))
965
        break;
966
    }
967
 
968
  return anything_changed;
969
}
970
 
971
/* Main entry point for the forward copy propagation optimization.  */
972
 
973
static unsigned int
974
copyprop_hardreg_forward (void)
975
{
976
  struct value_data *all_vd;
977
  basic_block bb;
978
  sbitmap visited;
979
  bool analyze_called = false;
980
 
981
  all_vd = XNEWVEC (struct value_data, last_basic_block);
982
 
983
  visited = sbitmap_alloc (last_basic_block);
984
  sbitmap_zero (visited);
985
 
986
  if (MAY_HAVE_DEBUG_STMTS)
987
    debug_insn_changes_pool
988
      = create_alloc_pool ("debug insn changes pool",
989
                           sizeof (struct queued_debug_insn_change), 256);
990
 
991
  FOR_EACH_BB (bb)
992
    {
993
      SET_BIT (visited, bb->index);
994
 
995
      /* If a block has a single predecessor, that we've already
996
         processed, begin with the value data that was live at
997
         the end of the predecessor block.  */
998
      /* ??? Ought to use more intelligent queuing of blocks.  */
999
      if (single_pred_p (bb)
1000
          && TEST_BIT (visited, single_pred (bb)->index)
1001
          && ! (single_pred_edge (bb)->flags & (EDGE_ABNORMAL_CALL | EDGE_EH)))
1002
        {
1003
          all_vd[bb->index] = all_vd[single_pred (bb)->index];
1004
          if (all_vd[bb->index].n_debug_insn_changes)
1005
            {
1006
              unsigned int regno;
1007
 
1008
              for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
1009
                {
1010
                  if (all_vd[bb->index].e[regno].debug_insn_changes)
1011
                    {
1012
                      all_vd[bb->index].e[regno].debug_insn_changes = NULL;
1013
                      if (--all_vd[bb->index].n_debug_insn_changes == 0)
1014
                        break;
1015
                    }
1016
                }
1017
            }
1018
        }
1019
      else
1020
        init_value_data (all_vd + bb->index);
1021
 
1022
      copyprop_hardreg_forward_1 (bb, all_vd + bb->index);
1023
    }
1024
 
1025
  if (MAY_HAVE_DEBUG_STMTS)
1026
    {
1027
      FOR_EACH_BB (bb)
1028
        if (TEST_BIT (visited, bb->index)
1029
            && all_vd[bb->index].n_debug_insn_changes)
1030
          {
1031
            unsigned int regno;
1032
            bitmap live;
1033
 
1034
            if (!analyze_called)
1035
              {
1036
                df_analyze ();
1037
                analyze_called = true;
1038
              }
1039
            live = df_get_live_out (bb);
1040
            for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
1041
              if (all_vd[bb->index].e[regno].debug_insn_changes)
1042
                {
1043
                  if (REGNO_REG_SET_P (live, regno))
1044
                    apply_debug_insn_changes (all_vd + bb->index, regno);
1045
                  if (all_vd[bb->index].n_debug_insn_changes == 0)
1046
                    break;
1047
                }
1048
          }
1049
 
1050
      free_alloc_pool (debug_insn_changes_pool);
1051
    }
1052
 
1053
  sbitmap_free (visited);
1054
  free (all_vd);
1055
  return 0;
1056
}
1057
 
1058
/* Dump the value chain data to stderr.  */
1059
 
1060
void
1061
debug_value_data (struct value_data *vd)
1062
{
1063
  HARD_REG_SET set;
1064
  unsigned int i, j;
1065
 
1066
  CLEAR_HARD_REG_SET (set);
1067
 
1068
  for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1069
    if (vd->e[i].oldest_regno == i)
1070
      {
1071
        if (vd->e[i].mode == VOIDmode)
1072
          {
1073
            if (vd->e[i].next_regno != INVALID_REGNUM)
1074
              fprintf (stderr, "[%u] Bad next_regno for empty chain (%u)\n",
1075
                       i, vd->e[i].next_regno);
1076
            continue;
1077
          }
1078
 
1079
        SET_HARD_REG_BIT (set, i);
1080
        fprintf (stderr, "[%u %s] ", i, GET_MODE_NAME (vd->e[i].mode));
1081
 
1082
        for (j = vd->e[i].next_regno;
1083
             j != INVALID_REGNUM;
1084
             j = vd->e[j].next_regno)
1085
          {
1086
            if (TEST_HARD_REG_BIT (set, j))
1087
              {
1088
                fprintf (stderr, "[%u] Loop in regno chain\n", j);
1089
                return;
1090
              }
1091
 
1092
            if (vd->e[j].oldest_regno != i)
1093
              {
1094
                fprintf (stderr, "[%u] Bad oldest_regno (%u)\n",
1095
                         j, vd->e[j].oldest_regno);
1096
                return;
1097
              }
1098
            SET_HARD_REG_BIT (set, j);
1099
            fprintf (stderr, "[%u %s] ", j, GET_MODE_NAME (vd->e[j].mode));
1100
          }
1101
        fputc ('\n', stderr);
1102
      }
1103
 
1104
  for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1105
    if (! TEST_HARD_REG_BIT (set, i)
1106
        && (vd->e[i].mode != VOIDmode
1107
            || vd->e[i].oldest_regno != i
1108
            || vd->e[i].next_regno != INVALID_REGNUM))
1109
      fprintf (stderr, "[%u] Non-empty reg in chain (%s %u %i)\n",
1110
               i, GET_MODE_NAME (vd->e[i].mode), vd->e[i].oldest_regno,
1111
               vd->e[i].next_regno);
1112
}
1113
 
1114
#ifdef ENABLE_CHECKING
1115
static void
1116
validate_value_data (struct value_data *vd)
1117
{
1118
  HARD_REG_SET set;
1119
  unsigned int i, j;
1120
 
1121
  CLEAR_HARD_REG_SET (set);
1122
 
1123
  for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1124
    if (vd->e[i].oldest_regno == i)
1125
      {
1126
        if (vd->e[i].mode == VOIDmode)
1127
          {
1128
            if (vd->e[i].next_regno != INVALID_REGNUM)
1129
              internal_error ("validate_value_data: [%u] Bad next_regno for empty chain (%u)",
1130
                              i, vd->e[i].next_regno);
1131
            continue;
1132
          }
1133
 
1134
        SET_HARD_REG_BIT (set, i);
1135
 
1136
        for (j = vd->e[i].next_regno;
1137
             j != INVALID_REGNUM;
1138
             j = vd->e[j].next_regno)
1139
          {
1140
            if (TEST_HARD_REG_BIT (set, j))
1141
              internal_error ("validate_value_data: Loop in regno chain (%u)",
1142
                              j);
1143
            if (vd->e[j].oldest_regno != i)
1144
              internal_error ("validate_value_data: [%u] Bad oldest_regno (%u)",
1145
                              j, vd->e[j].oldest_regno);
1146
 
1147
            SET_HARD_REG_BIT (set, j);
1148
          }
1149
      }
1150
 
1151
  for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1152
    if (! TEST_HARD_REG_BIT (set, i)
1153
        && (vd->e[i].mode != VOIDmode
1154
            || vd->e[i].oldest_regno != i
1155
            || vd->e[i].next_regno != INVALID_REGNUM))
1156
      internal_error ("validate_value_data: [%u] Non-empty reg in chain (%s %u %i)",
1157
                      i, GET_MODE_NAME (vd->e[i].mode), vd->e[i].oldest_regno,
1158
                      vd->e[i].next_regno);
1159
}
1160
#endif
1161
 
1162
static bool
1163
gate_handle_cprop (void)
1164
{
1165
  return (optimize > 0 && (flag_cprop_registers));
1166
}
1167
 
1168
 
1169
struct rtl_opt_pass pass_cprop_hardreg =
1170
{
1171
 {
1172
  RTL_PASS,
1173
  "cprop_hardreg",                      /* name */
1174
  gate_handle_cprop,                    /* gate */
1175
  copyprop_hardreg_forward,             /* execute */
1176
  NULL,                                 /* sub */
1177
  NULL,                                 /* next */
1178
  0,                                    /* static_pass_number */
1179
  TV_CPROP_REGISTERS,                   /* tv_id */
1180
  0,                                    /* properties_required */
1181
  0,                                    /* properties_provided */
1182
  0,                                    /* properties_destroyed */
1183
  0,                                    /* todo_flags_start */
1184
  TODO_dump_func | TODO_df_finish
1185
  | TODO_verify_rtl_sharing             /* todo_flags_finish */
1186
 }
1187
};

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