ldstopt.c 19.4 KB
Newer Older
Michael Beck's avatar
Michael Beck committed
1
2
3
4
5
6
7
/*
 * Project:     libFIRM
 * File name:   ir/opt/ldstopt.c
 * Purpose:     load store optimizations
 * Author:
 * Created:
 * CVS-ID:      $Id$
Götz Lindenmaier's avatar
Götz Lindenmaier committed
8
 * Copyright:   (c) 1998-2004 Universitt Karlsruhe
Michael Beck's avatar
Michael Beck committed
9
10
11
12
13
14
15
16
17
18
19
20
21
22
 * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
 */
# include "irnode_t.h"
# include "irgraph_t.h"
# include "irmode_t.h"
# include "iropt_t.h"
# include "ircons_t.h"
# include "irgmod.h"
# include "irgwalk.h"
# include "irvrfy.h"
# include "tv_t.h"
# include "dbginfo_t.h"
# include "iropt_dbg.h"
# include "irflag_t.h"
Michael Beck's avatar
Michael Beck committed
23
# include "array.h"
Michael Beck's avatar
Michael Beck committed
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
# include "firmstat.h"

#undef IMAX
#define IMAX(a,b)	((a) > (b) ? (a) : (b))

#define MAX_PROJ	IMAX(pn_Load_max, pn_Store_max)

/**
 * walker environment
 */
typedef struct _walk_env_t {
  struct obstack obst;		/**< list of all stores */
  int changes;
} walk_env_t;

39
40
41
42
43
44
45
/**
 * flags for Load/Store
 */
enum ldst_flags_t {
  LDST_VISITED = 1              /**< if set, this Load/Store is already visited */
};

Michael Beck's avatar
Michael Beck committed
46
47
48
49
/**
 * a Load/Store info
 */
typedef struct _ldst_info_t {
50
51
52
53
  ir_node  *projs[MAX_PROJ];    /**< list of Proj's of this node */
  ir_node  *exc_block;          /**< the exception block if available */
  int      exc_idx;             /**< predecessor index in the exception block */
  unsigned flags;               /**< flags */
Michael Beck's avatar
Michael Beck committed
54
55
} ldst_info_t;

56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
/**
 * flags for control flow
 */
enum block_flags_t {
  BLOCK_HAS_COND = 1,      /**< Block has conditional control flow */
  BLOCK_HAS_EXC  = 2       /**< Block has exceptionl control flow */
};

/**
 * a Block info
 */
typedef struct _block_info_t {
  unsigned flags;               /**< flags for the block */
} block_info_t;

Michael Beck's avatar
Michael Beck committed
71
72
73
74
75
76
77
78
79
80
81
/**
 * walker, clears all links first
 */
static void init_links(ir_node *n, void *env)
{
  set_irn_link(n, NULL);
}

/**
 * get the Load/Store info of a node
 */
82
static ldst_info_t *get_ldst_info(ir_node *node, walk_env_t *env)
Michael Beck's avatar
Michael Beck committed
83
84
85
86
87
88
89
90
91
92
93
94
95
{
  ldst_info_t *info = get_irn_link(node);

  if (! info) {
    info = obstack_alloc(&env->obst, sizeof(*info));

    memset(info, 0, sizeof(*info));

    set_irn_link(node, info);
  }
  return info;
}

96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
/**
 * get the Block info of a node
 */
static block_info_t *get_block_info(ir_node *node, walk_env_t *env)
{
  block_info_t *info = get_irn_link(node);

  if (! info) {
    info = obstack_alloc(&env->obst, sizeof(*info));

    memset(info, 0, sizeof(*info));

    set_irn_link(node, info);
  }
  return info;
}

Michael Beck's avatar
Michael Beck committed
113
/**
Michael Beck's avatar
Michael Beck committed
114
 * update the projection info for a Load/Store
Michael Beck's avatar
Michael Beck committed
115
 */
Michael Beck's avatar
Michael Beck committed
116
static int update_projs(ldst_info_t *info, ir_node *proj)
Michael Beck's avatar
Michael Beck committed
117
118
119
120
121
122
123
124
{
  long nr = get_Proj_proj(proj);

  assert(0 <= nr && nr <= MAX_PROJ && "Wrong proj from LoadStore");

  if (info->projs[nr]) {
    /* there is already one, do CSE */
    exchange(proj, info->projs[nr]);
Michael Beck's avatar
Michael Beck committed
125
    return 1;
Michael Beck's avatar
Michael Beck committed
126
  }
Michael Beck's avatar
Michael Beck committed
127
  else {
Michael Beck's avatar
Michael Beck committed
128
    info->projs[nr] = proj;
Michael Beck's avatar
Michael Beck committed
129
130
131
132
133
134
135
136
137
138
139
140
141
142
    return 0;
  }
}

/**
 * update the exception block info for a Load/Store
 */
static int update_exc(ldst_info_t *info, ir_node *block, int pos)
{
  assert(info->exc_block == NULL && "more than one exception block found");

  info->exc_block = block;
  info->exc_idx   = pos;
  return 0;
Michael Beck's avatar
Michael Beck committed
143
144
}

145
146
147
#define get_irn_out_n(node)     (unsigned)get_irn_link(node)
#define set_irn_out_n(node, n)  set_irn_link(adr, (void *)(n))

Michael Beck's avatar
Michael Beck committed
148
149
/**
 * walker, collects all Load/Store/Proj nodes
150
151
 *
 * walks form Start -> End
Michael Beck's avatar
Michael Beck committed
152
 */
Michael Beck's avatar
Michael Beck committed
153
static void collect_nodes(ir_node *node, void *env)
Michael Beck's avatar
Michael Beck committed
154
{
155
  ir_op       *op = get_irn_op(node);
Michael Beck's avatar
Michael Beck committed
156
  ir_node     *pred;
157
  ldst_info_t *ldst_info;
Michael Beck's avatar
Michael Beck committed
158
159
  walk_env_t  *wenv = env;

160
  if (op == op_Proj) {
161
162
163
    ir_node *adr;
    ir_op *op;

Michael Beck's avatar
Michael Beck committed
164
    pred = get_Proj_pred(node);
165
    op   = get_irn_op(pred);
Michael Beck's avatar
Michael Beck committed
166

167
    if (op == op_Load) {
168
      ldst_info = get_ldst_info(pred, wenv);
Michael Beck's avatar
Michael Beck committed
169

170
      wenv->changes |= update_projs(ldst_info, node);
171

172
173
174
175
176
177
      if ((ldst_info->flags & LDST_VISITED) == 0) {
        adr = get_Load_ptr(pred);
        set_irn_out_n(adr, get_irn_out_n(adr) + 1);

        ldst_info->flags |= LDST_VISITED;
      }
178
179
180
181
182
183
    }
    else if (op == op_Store) {
      ldst_info = get_ldst_info(pred, wenv);

      wenv->changes |= update_projs(ldst_info, node);

184
185
186
187
188
189
      if ((ldst_info->flags & LDST_VISITED) == 0) {
        adr = get_Store_ptr(pred);
        set_irn_out_n(adr, get_irn_out_n(adr) + 1);

        ldst_info->flags |= LDST_VISITED;
      }
Michael Beck's avatar
Michael Beck committed
190
191
    }
  }
192
  else if (op == op_Block) { /* check, if it's an exception block */
Michael Beck's avatar
Michael Beck committed
193
194
195
    int i, n;

    for (i = 0, n = get_Block_n_cfgpreds(node); i < n; ++i) {
196
197
198
      ir_node      *pred_block;
      block_info_t *bl_info;

Michael Beck's avatar
Michael Beck committed
199
200
      pred = skip_Proj(get_Block_cfgpred(node, i));

201
202
203
204
205
206
207
208
209
210
211
212
      /* ignore Bad predecessors, they will be removed later */
      if (is_Bad(pred))
	continue;

      pred_block = get_nodes_block(pred);
      bl_info    = get_block_info(pred_block, wenv);

      if (is_fragile_op(pred))
	bl_info->flags |= BLOCK_HAS_EXC;
      else if (is_forking_op(pred))
	bl_info->flags |= BLOCK_HAS_COND;

Michael Beck's avatar
Michael Beck committed
213
      if (get_irn_op(pred) == op_Load || get_irn_op(pred) == op_Store) {
214
        ldst_info = get_ldst_info(pred, wenv);
Michael Beck's avatar
Michael Beck committed
215

216
        wenv->changes |= update_exc(ldst_info, node, i);
Michael Beck's avatar
Michael Beck committed
217
      }
Michael Beck's avatar
Michael Beck committed
218
219
220
221
222
223
224
225
226
227
228
229
    }
  }
}

/**
 * optimize a Load
 */
static int optimize_load(ir_node *load)
{
  ldst_info_t *info = get_irn_link(load);
  ir_mode *load_mode = get_Load_mode(load);
  ir_node *pred, *mem, *ptr;
230
  int res = 0;
Michael Beck's avatar
Michael Beck committed
231

232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
  /* the address of the load to be optimized */
  ptr = get_Load_ptr(load);

  /*
   * Check if we can remove the exception form a Load:
   * this can be done, if the address is from an Sel(Alloc) and
   * the Sel type is a subtype of the alloc type.
   *
   * This optimizes some often used OO constructs,
   * like x = new O; x->t;
   */
  if (info->projs[pn_Load_X_except]) {
    if (get_irn_op(ptr) == op_Sel) {
      ir_node *mem = get_Sel_mem(ptr);

      if (get_irn_op(mem) == op_Alloc) {
        /* ok, check the types */
        entity *ent  = get_Sel_entity(ptr);
        type *s_type = get_entity_type(ent);
        type *a_type = get_Alloc_type(mem);

        if (is_subclass_of(s_type, a_type)) {
          /* ok, condition met: there can't be an exception because
           * alloc guarantees that enough memory was allocated */

          exchange(info->projs[pn_Load_X_except], new_Bad());
          info->projs[pn_Load_X_except] = NULL;
        }
      }
    }
    else if (get_irn_op(ptr) == op_Alloc) {
      /* simple case: a direct load after an Alloc. Firm Alloc throw
       * an exception in case of out-of-memory. So, there is no way for an
       * exception in this load.
       * This code is constructed by the "exception lowering" in the Jack compiler.
       */
       exchange(info->projs[pn_Load_X_except], new_Bad());
       info->projs[pn_Load_X_except] = NULL;
    }
  }

273
  /* do NOT touch volatile loads for now */
Michael Beck's avatar
Michael Beck committed
274
275
276
277
278
  if (get_Load_volatility(load) == volatility_is_volatile)
    return 0;

  if (! info->projs[pn_Load_res] && ! info->projs[pn_Load_X_except]) {
    /* a Load which value is neither used nor exception checked, remove it */
279
    mem  = get_Load_mem(load);
Michael Beck's avatar
Michael Beck committed
280
    exchange(info->projs[pn_Load_M], mem);
281
282

    return 1;
Michael Beck's avatar
Michael Beck committed
283
  }
Michael Beck's avatar
Michael Beck committed
284

285
  /* the mem of the Load. Must still be returned after optimization */
286
287
  mem  = get_Load_mem(load);

288
289
  if ((get_irn_opcode(ptr) == iro_SymConst) && (get_SymConst_kind(ptr) == symconst_addr_ent)) {
    entity *ent = get_SymConst_entity(ptr);
290

291
292
293
294
295
296
297
298
299
300
301
302
303
    assert(mode_is_reference(get_irn_mode(ptr)));

    if ((allocation_static == get_entity_allocation(ent)) &&
        (visibility_external_allocated != get_entity_visibility(ent))) {
      /* a static allocation that is not external: there should be NO exception
       * when loading. */

      /* no exception, clear the info field as it might be checked later again */
      if (info->projs[pn_Load_X_except]) {
        exchange(info->projs[pn_Load_X_except], new_Bad());
        info->projs[pn_Load_X_except] = NULL;
      }

Götz Lindenmaier's avatar
bugfix    
Götz Lindenmaier committed
304
305
306
307
308
      if (variability_constant == get_entity_variability(ent)
	  && is_atomic_entity(ent)) {   /* Might not be atomic after
					 lowering of Sels.  In this
					 case we could also load, but
					 it's more complicated. */
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
        /* more simpler case: we load the content of a constant value:
         * replace it by the constant itself
         */

        /* no memory */
        if (info->projs[pn_Load_M])
          exchange(info->projs[pn_Load_M], mem);

        /* no result :-) */
        if (info->projs[pn_Load_res])
          exchange(info->projs[pn_Load_res], copy_const_value(get_atomic_ent_value(ent)));

        return 1;
      }

      /* we changed the irg, but try further */
      res = 1;
    }
  }

329
330
331
332
333
  /* Check, if the address of this load is used more than once.
   * If not, this load cannot be removed in any case. */
  if (get_irn_out_n(ptr) <= 1)
    return 0;

334
335
  /* follow the memory chain as long as there are only Loads */
  for (pred = skip_Proj(mem); ; pred = skip_Proj(get_Load_mem(pred))) {
Michael Beck's avatar
Michael Beck committed
336
337

    /*
338
339
340
341
     * BEWARE: one might think that checking the modes is useless, because
     * if the pointers are identical, they refer to the same object.
     * This is only true in strong typed languages, not is C were the following
     * is possible a = *(type1 *)p; b = *(type2 *)p ...
Michael Beck's avatar
Michael Beck committed
342
343
     */

344
    if (get_irn_op(pred) == op_Store && get_Store_ptr(pred) == ptr &&
345
346
347
        get_irn_mode(get_Store_value(pred)) == load_mode) {
      ldst_info_t *pred_info = get_irn_link(pred);

348
      /*
349
350
       * a Load immediately after a Store -- a read after write.
       * We may remove the Load, if both Load & Store does not have an exception handler
351
352
       * OR they are in the same block. In the latter case the Load cannot
       * throw an exception when the previous Store was quiet.
353
354
355
356
       *
       * Why we need to check for Store Exc? If the Store cannot be executed (ROM)
       * the exception handler might simply jump into the load block :-(
       * We could make it a little bit better if we would know that the exception
357
       * handler of the Store jumps directly to the end...
358
       */
359
360
      if ((!pred_info->projs[pn_Store_X_except] && !info->projs[pn_Load_X_except]) ||
          get_nodes_block(load) == get_nodes_block(pred)) {
361
362
363
364
365
366
367
368
369
        DBG_OPT_RAW(pred, load);
        exchange( info->projs[pn_Load_res], get_Store_value(pred) );

        if (info->projs[pn_Load_M])
          exchange(info->projs[pn_Load_M], mem);

        /* no exception */
        if (info->projs[pn_Load_X_except])
          exchange( info->projs[pn_Load_X_except], new_Bad());
370
        return 1;
Michael Beck's avatar
Michael Beck committed
371
      }
372
373
374
375
    }
    else if (get_irn_op(pred) == op_Load && get_Load_ptr(pred) == ptr &&
             get_Load_mode(pred) == load_mode) {
      /*
376
       * a Load after a Load -- a read after read.
377
378
379
       * We may remove the second Load, if it does not have an exception handler
       * OR they are in the same block. In the later case the Load cannot
       * throw an exception when the previous Load was quiet.
380
       *
381
       * Here, there is no need to check if the previos Load has an exception hander because
382
       * they would have exact the same exception...
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
       */
      if (! info->projs[pn_Load_X_except] || get_nodes_block(load) == get_nodes_block(pred)) {
        ldst_info_t *pred_info = get_irn_link(pred);

        DBG_OPT_RAR(pred, load);

        if (pred_info->projs[pn_Load_res]) {
          /* we need a data proj from the previous load for this optimization */
          exchange( info->projs[pn_Load_res], pred_info->projs[pn_Load_res] );
          if (info->projs[pn_Load_M])
            exchange(info->projs[pn_Load_M], mem);
        }
        else {
          if (info->projs[pn_Load_res]) {
            set_Proj_pred(info->projs[pn_Load_res], pred);
            set_nodes_block(info->projs[pn_Load_res], get_nodes_block(pred));
          }
          if (info->projs[pn_Load_M]) {
            /* Actually, this if should not be necessary.  Construct the Loads
               properly!!! */
            exchange(info->projs[pn_Load_M], mem);
          }
        }

        /* no exception */
        if (info->projs[pn_Load_X_except])
          exchange(info->projs[pn_Load_X_except], new_Bad());

411
        return 1;
Michael Beck's avatar
Michael Beck committed
412
413
      }
    }
414

415
    /* follow only Load chains */
416
417
418
    if (get_irn_op(pred) != op_Load)
      break;
   }
Michael Beck's avatar
Michael Beck committed
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
  return res;
}

/**
 * optimize a Store
 */
static int optimize_store(ir_node *store)
{
  ldst_info_t *info = get_irn_link(store);
  ir_node *pred, *mem, *ptr, *value, *block;
  ir_mode *mode;
  int res = 0;

  if (get_Store_volatility(store) == volatility_is_volatile)
    return 0;

  /*
   * BEWARE: one might think that checking the modes is useless, because
   * if the pointers are identical, they refer to the same object.
   * This is only true in strong typed languages, not is C were the following
   * is possible *(type1 *)p = a; *(type2 *)p = b ...
   */

  ptr   = get_Store_ptr(store);
443
444
445
446
447
448
449

  /* Check, if the address of this load is used more than once.
   * If not, this load cannot be removed in any case. */
  if (get_irn_out_n(ptr) <= 1)
    return 0;

  block = get_nodes_block(store);
Michael Beck's avatar
Michael Beck committed
450
451
452
453
  mem   = get_Store_mem(store);
  value = get_Store_value(store);
  mode  = get_irn_mode(value);

454
455
456
  /* follow the memory chain as long as there are only Loads */
  for (pred = skip_Proj(mem); ; pred = skip_Proj(get_Load_mem(pred))) {
    ldst_info_t *pred_info = get_irn_link(pred);
Michael Beck's avatar
Michael Beck committed
457

458
459
460
    if (get_irn_op(pred) == op_Store && get_Store_ptr(pred) == ptr &&
        get_nodes_block(pred) == block && get_irn_mode(get_Store_value(pred)) == mode) {
      /*
461
       * a Store after a Store in the same block -- a write after write.
462
463
464
465
466
467
468
469
470
       * We may remove the first Store, if it does not have an exception handler.
       *
       * TODO: What, if both have the same exception handler ???
       */
      if (get_Store_volatility(pred) != volatility_is_volatile && !pred_info->projs[pn_Store_X_except]) {
        DBG_OPT_WAW(pred, store);
        exchange( pred_info->projs[pn_Store_M], get_Store_mem(pred) );
        return 1;
      }
Michael Beck's avatar
Michael Beck committed
471
    }
472
473
474
    else if (get_irn_op(pred) == op_Load && get_Load_ptr(pred) == ptr &&
             value == pred_info->projs[pn_Load_res]) {
      /*
475
       * a Store of a value after a Load -- a write after read.
476
477
478
479
480
481
482
       * We may remove the second Store, if it does not have an exception handler.
       */
      if (! info->projs[pn_Store_X_except]) {
        DBG_OPT_WAR(pred, store);
        exchange( info->projs[pn_Store_M], mem );
        return 1;
      }
Michael Beck's avatar
Michael Beck committed
483
    }
484

485
    /* follow only Load chains */
486
487
    if (get_irn_op(pred) != op_Load)
      break;
Michael Beck's avatar
Michael Beck committed
488
489
490
491
  }
  return res;
}

Michael Beck's avatar
Michael Beck committed
492
493
494
495
496
497
498
499
500
501
502
503
/**
 * walker, optimizes Phi after Stores:
 * Does the following optimization:
 *
 *   val1   val2   val3          val1  val2  val3
 *    |      |      |               \    |    /
 *   Str    Str    Str               \   |   /
 *      \    |    /                     Phi
 *       \   |   /                       |
 *        \  |  /                       Str
 *          Phi
 *
504
 * This removes the number of stores and allows for predicated execution.
Michael Beck's avatar
Michael Beck committed
505
506
 * Moves Stores back to the end of a function which may be bad
 *
507
 * Is only allowed if the predecessor blocks have only one successor.
Michael Beck's avatar
Michael Beck committed
508
 */
509
static int optimize_phi(ir_node *phi, void *env)
Michael Beck's avatar
Michael Beck committed
510
{
511
  walk_env_t *wenv = env;
Michael Beck's avatar
Michael Beck committed
512
  int i, n;
513
  ir_node *store, *ptr, *block, *phiM, *phiD, *exc, *projM;
Michael Beck's avatar
Michael Beck committed
514
515
516
517
518
  ir_mode *mode;
  ir_node **inM, **inD;
  int *idx;
  dbg_info *db = NULL;
  ldst_info_t *info;
519
  block_info_t *bl_info;
Michael Beck's avatar
Michael Beck committed
520
521
522
523
524
525
526
527
528
529
530
531
532

  /* Must be a memory Phi */
  if (get_irn_mode(phi) != mode_M)
    return 0;

  n = get_Phi_n_preds(phi);
  if (n <= 0)
    return 0;

  store = skip_Proj(get_Phi_pred(phi, 0));
  if (get_irn_op(store) != op_Store)
    return 0;

533
534
535
536
537
538
539
540
541
  /* abort on bad blocks */
  if (is_Bad(get_nodes_block(store)))
    return 0;

  /* check if the block has only one output */
  bl_info = get_irn_link(get_nodes_block(store));
  if (bl_info->flags)
    return 0;

Michael Beck's avatar
Michael Beck committed
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
  /* this is the address of the store */
  ptr  = get_Store_ptr(store);
  mode = get_irn_mode(get_Store_value(store));
  info = get_irn_link(store);
  exc  = info->exc_block;

  for (i = 1; i < n; ++i) {
    ir_node *pred = skip_Proj(get_Phi_pred(phi, i));

    if (get_irn_op(pred) != op_Store)
      return 0;

    if (mode != get_irn_mode(get_Store_value(pred)) || ptr != get_Store_ptr(pred))
      return 0;

    info = get_irn_link(pred);

    /* check, if all stores have the same exception flow */
    if (exc != info->exc_block)
      return 0;
562
563
564
565
566
567
568
569
570

    /* abort on bad blocks */
    if (is_Bad(get_nodes_block(store)))
      return 0;

    /* check if the block has only one output */
    bl_info = get_irn_link(get_nodes_block(store));
    if (bl_info->flags)
      return 0;
Michael Beck's avatar
Michael Beck committed
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
  }

  /*
   * ok, when we are here, we found all predecessors of a Phi that
   * are Stores to the same address. That means whatever we do before
   * we enter the block of the Phi, we do a Store.
   * So, we can move the store to the current block:
   *
   *   val1    val2    val3          val1  val2  val3
   *    |       |       |               \    |    /
   * | Str | | Str | | Str |             \   |   /
   *      \     |     /                     Phi
   *       \    |    /                       |
   *        \   |   /                       Str
   *           Phi
   *
587
   * Is only allowed if the predecessor blocks have only one successor.
Michael Beck's avatar
Michael Beck committed
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
   */

  /* first step: collect all inputs */
  NEW_ARR_A(ir_node *, inM, n);
  NEW_ARR_A(ir_node *, inD, n);
  NEW_ARR_A(int, idx, n);

  for (i = 0; i < n; ++i) {
    ir_node *pred = skip_Proj(get_Phi_pred(phi, i));
    info = get_irn_link(pred);

    inM[i] = get_Store_mem(pred);
    inD[i] = get_Store_value(pred);
    idx[i] = info->exc_idx;
  }
  block = get_nodes_block(phi);

  /* second step: create a new memory Phi */
  phiM = new_rd_Phi(get_irn_dbg_info(phi), current_ir_graph, block, n, inM, mode_M);

  /* third step: create a new data Phi */
  phiD = new_rd_Phi(get_irn_dbg_info(phi), current_ir_graph, block, n, inD, mode);

  /* fourth step: create the Store */
  store = new_rd_Store(db, current_ir_graph, block, phiM, ptr, phiD);
613
614
615
616
  projM = new_rd_Proj(NULL, current_ir_graph, block, store, mode_M, pn_Store_M);

  info = get_ldst_info(store, wenv);
  info->projs[pn_Store_M] = projM;
Michael Beck's avatar
Michael Beck committed
617
618
619
620
621

  /* fifths step: repair exception flow */
  if (exc) {
    ir_node *projX = new_rd_Proj(NULL, current_ir_graph, block, store, mode_X, pn_Store_X_except);

622
623
624
625
    info->projs[pn_Store_X_except] = projX;
    info->exc_block                = exc;
    info->exc_idx                  = idx[0];

Michael Beck's avatar
Michael Beck committed
626
627
628
629
630
631
632
633
634
635
    for (i = 0; i < n; ++i) {
      set_Block_cfgpred(exc, idx[i], projX);
    }

    if (n > 1) {
      /* the exception block should be optimized as some inputs are identical now */
    }
  }

  /* sixt step: replace old Phi */
636
  exchange(phi, projM);
Michael Beck's avatar
Michael Beck committed
637
638
639
640

  return 1;
}

Michael Beck's avatar
Michael Beck committed
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
/**
 * walker, collects all Load/Store/Proj nodes
 */
static void do_load_store_optimize(ir_node *n, void *env)
{
  walk_env_t *wenv = env;

  switch (get_irn_opcode(n)) {

  case iro_Load:
    wenv->changes |= optimize_load(n);
    break;

  case iro_Store:
    wenv->changes |= optimize_store(n);
    break;

658
659
  case iro_Phi:
    wenv->changes |= optimize_phi(n, env);
Michael Beck's avatar
Michael Beck committed
660

Michael Beck's avatar
Michael Beck committed
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
  default:
    ;
  }
}

/*
 * do the load store optimization
 */
void optimize_load_store(ir_graph *irg)
{
  walk_env_t env;

  assert(get_irg_phase_state(irg) != phase_building);

  if (!get_opt_redundant_LoadStore())
    return;

  obstack_init(&env.obst);
  env.changes = 0;

  /* init the links, then collect Loads/Stores/Proj's in lists */
  irg_walk_graph(irg, init_links, collect_nodes, &env);

  /* now we have collected enough information, optimize */
  irg_walk_graph(irg, NULL, do_load_store_optimize, &env);

  obstack_free(&env.obst, NULL);

  /* Handle graph state */
  if (env.changes) {
    if (get_irg_outs_state(current_ir_graph) == outs_consistent)
      set_irg_outs_inconsistent(current_ir_graph);

    /* is this really needed: Yes, as exception block may get bad but this might be tested */
    if (get_irg_dom_state(current_ir_graph) == dom_consistent)
      set_irg_dom_inconsistent(current_ir_graph);
  }
}