ldstopt.c 49.8 KB
Newer Older
Christian Würdig's avatar
Christian Würdig committed
1
/*
Michael Beck's avatar
Michael Beck committed
2
 * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
Christian Würdig's avatar
Christian Würdig committed
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
 *
 * This file is part of libFirm.
 *
 * This file may be distributed and/or modified under the terms of the
 * GNU General Public License version 2 as published by the Free Software
 * Foundation and appearing in the file LICENSE.GPL included in the
 * packaging of this file.
 *
 * Licensees holding valid libFirm Professional Edition licenses may use
 * this file in accordance with the libFirm Commercial License.
 * Agreement provided with the Software.
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE.
 */

Michael Beck's avatar
Michael Beck committed
20
21
22
23
24
/**
 * @file
 * @brief   Load/Store optimizations.
 * @author  Michael Beck
 * @version $Id$
Michael Beck's avatar
Michael Beck committed
25
 */
Michael Beck's avatar
Michael Beck committed
26
27
28
29
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

30
#include <string.h>
Michael Beck's avatar
Michael Beck committed
31

32
#include "iroptimize.h"
33
34
35
36
37
38
39
40
41
42
43
44
45
46
#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"
#include "array.h"
#include "irhooks.h"
Michael Beck's avatar
BugFix:    
Michael Beck committed
47
#include "iredges.h"
48
49
#include "irtools.h"
#include "opt_polymorphy.h"
50
#include "irmemory.h"
51
#include "xmalloc.h"
52
53
54
55
56
57
#include "irphase_t.h"
#include "irgopt.h"
#include "debug.h"

/** The debug handle. */
DEBUG_ONLY(static firm_dbg_module_t *dbg;)
58
59
60
61

#ifdef DO_CACHEOPT
#include "cacheopt/cachesim.h"
#endif
Michael Beck's avatar
Michael Beck committed
62
63
64
65

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

66
#define MAX_PROJ	IMAX(IMAX(pn_Load_max, pn_Store_max), pn_Call_max)
Michael Beck's avatar
Michael Beck committed
67

68
enum changes_t {
69
70
	DF_CHANGED = 1,       /**< data flow changed */
	CF_CHANGED = 2,       /**< control flow changed */
71
72
};

Michael Beck's avatar
Michael Beck committed
73
74
75
76
/**
 * walker environment
 */
typedef struct _walk_env_t {
77
78
	struct obstack obst;          /**< list of all stores */
	unsigned changes;             /**< a bitmask of graph changes */
Michael Beck's avatar
Michael Beck committed
79
80
} walk_env_t;

81
/** A Load/Store info. */
Michael Beck's avatar
Michael Beck committed
82
typedef struct _ldst_info_t {
83
84
85
86
	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 visited;             /**< visited counter for breaking loops */
Michael Beck's avatar
Michael Beck committed
87
88
} ldst_info_t;

89
/**
90
 * flags for control flow.
91
92
 */
enum block_flags_t {
93
94
	BLOCK_HAS_COND = 1,      /**< Block has conditional control flow */
	BLOCK_HAS_EXC  = 2       /**< Block has exceptional control flow */
95
96
97
};

/**
98
 * a Block info.
99
100
 */
typedef struct _block_info_t {
101
	unsigned flags;               /**< flags for the block */
102
103
} block_info_t;

104
105
106
107
108
109
110
/** the master visited flag for loop detection. */
static unsigned master_visited = 0;

#define INC_MASTER()       ++master_visited
#define MARK_NODE(info)    (info)->visited = master_visited
#define NODE_VISITED(info) (info)->visited >= master_visited

Michael Beck's avatar
Michael Beck committed
111
112
113
/**
 * get the Load/Store info of a node
 */
114
static ldst_info_t *get_ldst_info(ir_node *node, struct obstack *obst) {
115
	ldst_info_t *info = get_irn_link(node);
Michael Beck's avatar
Michael Beck committed
116

117
	if (! info) {
118
		info = obstack_alloc(obst, sizeof(*info));
119
120
121
122
123
		memset(info, 0, sizeof(*info));
		set_irn_link(node, info);
	}
	return info;
}  /* get_ldst_info */
Michael Beck's avatar
Michael Beck committed
124

125
126
127
/**
 * get the Block info of a node
 */
128
static block_info_t *get_block_info(ir_node *node, struct obstack *obst) {
129
	block_info_t *info = get_irn_link(node);
130

131
	if (! info) {
132
		info = obstack_alloc(obst, sizeof(*info));
133
134
135
136
137
		memset(info, 0, sizeof(*info));
		set_irn_link(node, info);
	}
	return info;
}  /* get_block_info */
138

Michael Beck's avatar
Michael Beck committed
139
/**
Michael Beck's avatar
Michael Beck committed
140
 * update the projection info for a Load/Store
Michael Beck's avatar
Michael Beck committed
141
 */
142
static unsigned update_projs(ldst_info_t *info, ir_node *proj)
Michael Beck's avatar
Michael Beck committed
143
{
144
	long nr = get_Proj_proj(proj);
Michael Beck's avatar
Michael Beck committed
145

146
	assert(0 <= nr && nr <= MAX_PROJ && "Wrong proj from LoadStore");
Michael Beck's avatar
Michael Beck committed
147

148
149
150
151
152
153
154
155
156
157
	if (info->projs[nr]) {
		/* there is already one, do CSE */
		exchange(proj, info->projs[nr]);
		return DF_CHANGED;
	}
	else {
		info->projs[nr] = proj;
		return 0;
	}
}  /* update_projs */
Michael Beck's avatar
Michael Beck committed
158
159

/**
160
161
162
163
164
 * update the exception block info for a Load/Store node.
 *
 * @param info   the load/store info struct
 * @param block  the exception handler block for this load/store
 * @param pos    the control flow input of the block
Michael Beck's avatar
Michael Beck committed
165
 */
166
static unsigned update_exc(ldst_info_t *info, ir_node *block, int pos)
Michael Beck's avatar
Michael Beck committed
167
{
168
	assert(info->exc_block == NULL && "more than one exception block found");
Michael Beck's avatar
Michael Beck committed
169

170
171
172
173
	info->exc_block = block;
	info->exc_idx   = pos;
	return 0;
}  /* update_exc */
Michael Beck's avatar
Michael Beck committed
174

175
/** Return the number of uses of an address node */
Michael Beck's avatar
BugFix:    
Michael Beck committed
176
#define get_irn_n_uses(adr)     get_irn_n_edges(adr)
177

Michael Beck's avatar
Michael Beck committed
178
179
/**
 * walker, collects all Load/Store/Proj nodes
180
 *
181
 * walks from Start -> End
Michael Beck's avatar
Michael Beck committed
182
 */
Michael Beck's avatar
Michael Beck committed
183
static void collect_nodes(ir_node *node, void *env)
Michael Beck's avatar
Michael Beck committed
184
{
185
	ir_opcode   opcode = get_irn_opcode(node);
186
187
188
189
	ir_node     *pred, *blk, *pred_blk;
	ldst_info_t *ldst_info;
	walk_env_t  *wenv = env;

190
191
192
	if (opcode == iro_Proj) {
		pred   = get_Proj_pred(node);
		opcode = get_irn_opcode(pred);
193

194
		if (opcode == iro_Load || opcode == iro_Store || opcode == iro_Call) {
195
			ldst_info = get_ldst_info(pred, &wenv->obst);
196
197
198
199

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

			/*
200
201
202
203
204
			 * Place the Proj's to the same block as the
			 * predecessor Load. This is always ok and prevents
			 * "non-SSA" form after optimizations if the Proj
			 * is in a wrong block.
			 */
205
206
207
208
209
210
211
			blk      = get_nodes_block(node);
			pred_blk = get_nodes_block(pred);
			if (blk != pred_blk) {
				wenv->changes |= DF_CHANGED;
				set_nodes_block(node, pred_blk);
			}
		}
212
	} else if (opcode == iro_Block) {
213
214
215
		int i;

		for (i = get_Block_n_cfgpreds(node) - 1; i >= 0; --i) {
216
			ir_node      *pred_block, *proj;
217
			block_info_t *bl_info;
218
219
220
			int          is_exc = 0;

			pred = proj = get_Block_cfgpred(node, i);
221

222
223
224
225
			if (is_Proj(proj)) {
				pred   = get_Proj_pred(proj);
				is_exc = get_Proj_proj(proj) == pn_Generic_X_except;
			}
226
227
228
229
230
231

			/* ignore Bad predecessors, they will be removed later */
			if (is_Bad(pred))
				continue;

			pred_block = get_nodes_block(pred);
232
			bl_info    = get_block_info(pred_block, &wenv->obst);
233

234
			if (is_fragile_op(pred) && is_exc)
235
236
237
238
				bl_info->flags |= BLOCK_HAS_EXC;
			else if (is_irn_forking(pred))
				bl_info->flags |= BLOCK_HAS_COND;

239
240
			opcode = get_irn_opcode(pred);
			if (is_exc && (opcode == iro_Load || opcode == iro_Store || opcode == iro_Call)) {
241
				ldst_info = get_ldst_info(pred, &wenv->obst);
242
243
244
245
246
247

				wenv->changes |= update_exc(ldst_info, node, i);
			}
		}
	}
}  /* collect_nodes */
Michael Beck's avatar
Michael Beck committed
248

Michael Beck's avatar
Michael Beck committed
249
/**
250
 * Returns an entity if the address ptr points to a constant one.
251
252
253
254
 *
 * @param ptr  the address
 *
 * @return an entity or NULL
Michael Beck's avatar
Michael Beck committed
255
 */
256
static ir_entity *find_constant_entity(ir_node *ptr)
Michael Beck's avatar
Michael Beck committed
257
{
258
	for (;;) {
259
		if (is_SymConst(ptr) && get_SymConst_kind(ptr) == symconst_addr_ent) {
260
261
262
263
			ir_entity *ent = get_SymConst_entity(ptr);
			if (variability_constant == get_entity_variability(ent))
				return ent;
			return NULL;
264
		} else if (is_Sel(ptr)) {
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
			ir_entity *ent = get_Sel_entity(ptr);
			ir_type   *tp  = get_entity_owner(ent);

			/* Do not fiddle with polymorphism. */
			if (is_Class_type(get_entity_owner(ent)) &&
				((get_entity_n_overwrites(ent)    != 0) ||
				(get_entity_n_overwrittenby(ent) != 0)   ) )
				return NULL;

			if (is_Array_type(tp)) {
				/* check bounds */
				int i, n;

				for (i = 0, n = get_Sel_n_indexs(ptr); i < n; ++i) {
					ir_node *bound;
					tarval *tlower, *tupper;
					ir_node *index = get_Sel_index(ptr, i);
					tarval *tv     = computed_value(index);

					/* check if the index is constant */
					if (tv == tarval_bad)
						return NULL;

					bound  = get_array_lower_bound(tp, i);
					tlower = computed_value(bound);
					bound  = get_array_upper_bound(tp, i);
					tupper = computed_value(bound);

					if (tlower == tarval_bad || tupper == tarval_bad)
						return NULL;

					if (tarval_cmp(tv, tlower) & pn_Cmp_Lt)
						return NULL;
					if (tarval_cmp(tupper, tv) & pn_Cmp_Lt)
						return NULL;

					/* ok, bounds check finished */
				}
			}

			if (variability_constant == get_entity_variability(ent))
				return ent;

			/* try next */
			ptr = get_Sel_ptr(ptr);
		} else
			return NULL;
	}
}  /* find_constant_entity */
Michael Beck's avatar
Michael Beck committed
314

Michael Beck's avatar
Michael Beck committed
315
316
317
/**
 * Return the Selection index of a Sel node from dimension n
 */
318
static long get_Sel_array_index_long(ir_node *n, int dim) {
319
	ir_node *index = get_Sel_index(n, dim);
Michael Beck's avatar
Michael Beck committed
320
	assert(is_Const(index));
321
322
	return get_tarval_long(get_Const_tarval(index));
}  /* get_Sel_array_index_long */
323

Michael Beck's avatar
Michael Beck committed
324
325
326
327
328
329
330
331
/**
 * Returns the accessed component graph path for an
 * node computing an address.
 *
 * @param ptr    the node computing the address
 * @param depth  current depth in steps upward from the root
 *               of the address
 */
Götz Lindenmaier's avatar
bugfix    
Götz Lindenmaier committed
332
static compound_graph_path *rec_get_accessed_path(ir_node *ptr, int depth) {
333
334
335
336
	compound_graph_path *res = NULL;
	ir_entity           *root, *field;
	int                 path_len, pos;

337
	if (is_SymConst(ptr)) {
338
339
340
341
342
343
344
345
		/* a SymConst. If the depth is 0, this is an access to a global
		 * entity and we don't need a component path, else we know
		 * at least it's length.
		 */
		assert(get_SymConst_kind(ptr) == symconst_addr_ent);
		root = get_SymConst_entity(ptr);
		res = (depth == 0) ? NULL : new_compound_graph_path(get_entity_type(root), depth);
	} else {
346
		assert(is_Sel(ptr));
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
		/* it's a Sel, go up until we find the root */
		res = rec_get_accessed_path(get_Sel_ptr(ptr), depth+1);

		/* fill up the step in the path at the current position */
		field    = get_Sel_entity(ptr);
		path_len = get_compound_graph_path_length(res);
		pos      = path_len - depth - 1;
		set_compound_graph_path_node(res, pos, field);

		if (is_Array_type(get_entity_owner(field))) {
			assert(get_Sel_n_indexs(ptr) == 1 && "multi dim arrays not implemented");
			set_compound_graph_path_array_index(res, pos, get_Sel_array_index_long(ptr, 0));
		}
	}
	return res;
}  /* rec_get_accessed_path */
363

364
365
366
/**
 * Returns an access path or NULL.  The access path is only
 * valid, if the graph is in phase_high and _no_ address computation is used.
Michael Beck's avatar
Michael Beck committed
367
 */
Götz Lindenmaier's avatar
bugfix    
Götz Lindenmaier committed
368
static compound_graph_path *get_accessed_path(ir_node *ptr) {
369
370
	return rec_get_accessed_path(ptr, 0);
}  /* get_accessed_path */
371

372
373
374
375
376
377
378
379
380
381
382
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
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
typedef struct path_entry {
	ir_entity         *ent;
	struct path_entry *next;
	long              index;
} path_entry;

static ir_node *rec_find_compound_ent_value(ir_node *ptr, path_entry *next) {
	path_entry       entry, *p;
	ir_entity        *ent;
	ir_initializer_t *initializer;

	entry.next      = next;

	if (is_Sel(ptr)) {
		ir_entity *field;
		ir_type   *tp;

		entry.ent = field = get_Sel_entity(ptr);
		tp = get_entity_owner(field);
		if (is_Array_type(tp)) {
			assert(get_Sel_n_indexs(ptr) == 1 && "multi dim arrays not implemented");
			entry.index     = get_Sel_array_index_long(ptr, 0) - get_array_lower_bound_int(tp, 0);
		} else {
			int i, n_members = get_compound_n_members(tp);
			for (i = 0; i < n_members; ++i) {
				if (get_compound_member(tp, i) == field)
					break;
			}
			if (i >= n_members) {
				/* not found: should NOT happen */
				return NULL;
			}
			entry.index = i;
		}
		return rec_find_compound_ent_value(get_Sel_ptr(ptr), &entry);
	}

	/* found the end */
	assert(is_SymConst(ptr));

	ent = get_SymConst_entity(ptr);
	initializer = get_entity_initializer(ent);
	for (p = next; p != NULL; p = p->next) {
		unsigned n;

		if (initializer->kind != IR_INITIALIZER_COMPOUND)
			return NULL;

		n = get_initializer_compound_n_entries(initializer);
		if (p->index >= n)
			return NULL;
		initializer = get_initializer_compound_value(initializer, p->index);
	}

	switch (initializer->kind) {
	case IR_INITIALIZER_CONST:
		return get_initializer_const_value(initializer);
	case IR_INITIALIZER_TARVAL:
	case IR_INITIALIZER_NULL:
	default:
		return NULL;
	}
}

static ir_node *find_compound_ent_value(ir_node *ptr) {
	return rec_find_compound_ent_value(ptr, NULL);
}

440
441
442
443
444
445
446
/* forward */
static void reduce_adr_usage(ir_node *ptr);

/**
 * Update a Load that may lost it's usage.
 */
static void handle_load_update(ir_node *load) {
447
	ldst_info_t *info = get_irn_link(load);
448

449
450
451
	/* do NOT touch volatile loads for now */
	if (get_Load_volatility(load) == volatility_is_volatile)
		return;
452

453
454
455
	if (! info->projs[pn_Load_res] && ! info->projs[pn_Load_X_except]) {
		ir_node *ptr = get_Load_ptr(load);
		ir_node *mem = get_Load_mem(load);
456

457
458
		/* a Load which value is neither used nor exception checked, remove it */
		exchange(info->projs[pn_Load_M], mem);
459
460
		if (info->projs[pn_Load_X_regular])
			exchange(info->projs[pn_Load_X_regular], new_r_Jmp(current_ir_graph, get_nodes_block(load)));
461
		kill_node(load);
462
463
464
		reduce_adr_usage(ptr);
	}
}  /* handle_load_update */
465
466
467
468
469
470

/**
 * A Use of an address node is vanished. Check if this was a Proj
 * node and update the counters.
 */
static void reduce_adr_usage(ir_node *ptr) {
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
	if (is_Proj(ptr)) {
		if (get_irn_n_edges(ptr) <= 0) {
			/* this Proj is dead now */
			ir_node *pred = get_Proj_pred(ptr);

			if (is_Load(pred)) {
				ldst_info_t *info = get_irn_link(pred);
				info->projs[get_Proj_proj(ptr)] = NULL;

				/* this node lost it's result proj, handle that */
				handle_load_update(pred);
			}
		}
	}
}  /* reduce_adr_usage */
486

487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
/**
 * Check, if an already existing value of mode old_mode can be converted
 * into the needed one new_mode without loss.
 */
static int can_use_stored_value(ir_mode *old_mode, ir_mode *new_mode) {
	if (old_mode == new_mode)
		return 1;

	/* if both modes are two-complement ones, we can always convert the
	   Stored value into the needed one. */
	if (get_mode_size_bits(old_mode) >= get_mode_size_bits(new_mode) &&
		  get_mode_arithmetic(old_mode) == irma_twos_complement &&
		  get_mode_arithmetic(new_mode) == irma_twos_complement)
		return 1;
	return 0;
}  /* can_use_stored_value */

Michael Beck's avatar
Michael Beck committed
504
/**
505
506
507
508
509
510
511
512
513
514
515
 * Check whether a Call is at least pure, ie. does only read memory.
 */
static unsigned is_Call_pure(ir_node *call) {
	ir_type *call_tp = get_Call_type(call);
	unsigned prop = get_method_additional_properties(call_tp);

	/* check first the call type */
	if ((prop & (mtp_property_const|mtp_property_pure)) == 0) {
		/* try the called entity */
		ir_node *ptr = get_Call_ptr(call);

516
517
		if (is_Global(ptr)) {
			ir_entity *ent = get_Global_entity(ptr);
518
519
520
521
522
523
524
525
526
527
528

			prop = get_entity_additional_properties(ent);
		}
	}
	return (prop & (mtp_property_const|mtp_property_pure)) != 0;
}  /* is_Call_pure */

/**
 * Follow the memory chain as long as there are only Loads,
 * alias free Stores, and constant Calls and try to replace the
 * current Load by a previous ones.
Michael Beck's avatar
Michael Beck committed
529
530
531
532
533
534
 * Note that in unreachable loops it might happen that we reach
 * load again, as well as we can fall into a cycle.
 * We break such cycles using a special visited flag.
 *
 * INC_MASTER() must be called before dive into
 */
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
static unsigned follow_Mem_chain(ir_node *load, ir_node *curr) {
	unsigned res = 0;
	ldst_info_t *info = get_irn_link(load);
	ir_node *pred;
	ir_node *ptr       = get_Load_ptr(load);
	ir_node *mem       = get_Load_mem(load);
	ir_mode *load_mode = get_Load_mode(load);

	for (pred = curr; load != pred; ) {
		ldst_info_t *pred_info = get_irn_link(pred);

		/*
		 * 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 in C were the following
		 * is possible a = *(ir_type1 *)p; b = *(ir_type2 *)p ...
		 */
552
		if (is_Store(pred) && get_Store_ptr(pred) == ptr &&
553
		    can_use_stored_value(get_irn_mode(get_Store_value(pred)), load_mode)) {
554
555
556
			/*
			 * 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
557
			 * OR they are in the same MacroBlock. In the latter case the Load cannot
558
559
560
561
			 * throw an exception when the previous Store was quiet.
			 *
			 * Why we need to check for Store Exception? If the Store cannot
			 * be executed (ROM) the exception handler might simply jump into
562
			 * the load MacroBlock :-(
563
564
565
			 * We could make it a little bit better if we would know that the exception
			 * handler of the Store jumps directly to the end...
			 */
566
			if ((pred_info->projs[pn_Store_X_except] == NULL && info->projs[pn_Load_X_except] == NULL) ||
567
			    get_nodes_MacroBlock(load) == get_nodes_MacroBlock(pred)) {
568
569
570
				ir_node *value = get_Store_value(pred);

				DBG_OPT_RAW(load, value);
571
572
573
574
575
576

				/* add an convert if needed */
				if (get_irn_mode(get_Store_value(pred)) != load_mode) {
					value = new_r_Conv(current_ir_graph, get_nodes_block(load), value, load_mode);
				}

577
578
579
580
581
582
583
584
				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());
					res |= CF_CHANGED;
				}
585
586
587
588
				if (info->projs[pn_Load_X_regular]) {
					exchange( info->projs[pn_Load_X_regular], new_r_Jmp(current_ir_graph, get_nodes_block(load)));
					res |= CF_CHANGED;
				}
589
590
591
592

				if (info->projs[pn_Load_res])
					exchange(info->projs[pn_Load_res], value);

593
				kill_node(load);
594
595
596
				reduce_adr_usage(ptr);
				return res | DF_CHANGED;
			}
597
		} else if (is_Load(pred) && get_Load_ptr(pred) == ptr &&
598
		           can_use_stored_value(get_Load_mode(pred), load_mode)) {
599
600
601
			/*
			 * a Load after a Load -- a read after read.
			 * We may remove the second Load, if it does not have an exception handler
602
			 * OR they are in the same MacroBlock. In the later case the Load cannot
603
604
605
606
607
			 * throw an exception when the previous Load was quiet.
			 *
			 * Here, there is no need to check if the previous Load has an exception
			 * hander because they would have exact the same exception...
			 */
608
			if (info->projs[pn_Load_X_except] == NULL || get_nodes_MacroBlock(load) == get_nodes_MacroBlock(pred)) {
609
610
				ir_node *value;

611
612
				DBG_OPT_RAR(load, pred);

613
614
615
616
617
618
619
				/* the result is used */
				if (info->projs[pn_Load_res]) {
					if (pred_info->projs[pn_Load_res] == NULL) {
						/* create a new Proj again */
						pred_info->projs[pn_Load_res] = new_r_Proj(current_ir_graph, get_nodes_block(pred), pred, get_Load_mode(pred), pn_Load_res);
					}
					value = pred_info->projs[pn_Load_res];
620
621
622
623
624
625

					/* add an convert if needed */
					if (get_Load_mode(pred) != load_mode) {
						value = new_r_Conv(current_ir_graph, get_nodes_block(load), value, load_mode);
					}

626
					exchange(info->projs[pn_Load_res], value);
627
628
				}

629
630
631
				if (info->projs[pn_Load_M])
					exchange(info->projs[pn_Load_M], mem);

632
633
634
635
636
				/* no exception */
				if (info->projs[pn_Load_X_except]) {
					exchange(info->projs[pn_Load_X_except], new_Bad());
					res |= CF_CHANGED;
				}
637
638
639
640
				if (info->projs[pn_Load_X_regular]) {
					exchange( info->projs[pn_Load_X_regular], new_r_Jmp(current_ir_graph, get_nodes_block(load)));
					res |= CF_CHANGED;
				}
641

642
				kill_node(load);
643
644
645
646
647
				reduce_adr_usage(ptr);
				return res |= DF_CHANGED;
			}
		}

648
		if (is_Store(pred)) {
649
			/* check if we can pass through this store */
650
651
652
653
			ir_alias_relation rel = get_alias_relation(
				current_ir_graph,
				get_Store_ptr(pred),
				get_irn_mode(get_Store_value(pred)),
654
				ptr, load_mode);
655
			/* if the might be an alias, we cannot pass this Store */
Michael Beck's avatar
Michael Beck committed
656
			if (rel != ir_no_alias)
657
658
				break;
			pred = skip_Proj(get_Store_mem(pred));
659
		} else if (is_Load(pred)) {
660
			pred = skip_Proj(get_Load_mem(pred));
661
662
663
664
665
666
667
668
669
		} else if (is_Call(pred)) {
			if (is_Call_pure(pred)) {
				/* The called graph is at least pure, so there are no Store's
				   in it. We can handle it like a Load and skip it. */
				pred = skip_Proj(get_Call_mem(pred));
			} else {
				/* there might be Store's in the graph, stop here */
				break;
			}
670
671
672
673
674
675
676
677
678
679
680
		} else {
			/* follow only Load chains */
			break;
		}

		/* check for cycles */
		if (NODE_VISITED(pred_info))
			break;
		MARK_NODE(pred_info);
	}

681
	if (is_Sync(pred)) {
682
683
684
685
686
687
		int i;

		/* handle all Sync predecessors */
		for (i = get_Sync_n_preds(pred) - 1; i >= 0; --i) {
			res |= follow_Mem_chain(load, skip_Proj(get_Sync_pred(pred, i)));
			if (res)
688
				return res;
689
690
691
692
693
		}
	}

	return res;
}  /* follow_Mem_chain */
Michael Beck's avatar
Michael Beck committed
694

Michael Beck's avatar
Michael Beck committed
695
696
/**
 * optimize a Load
697
698
 *
 * @param load  the Load node
Michael Beck's avatar
Michael Beck committed
699
 */
700
static unsigned optimize_load(ir_node *load)
Michael Beck's avatar
Michael Beck committed
701
{
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
	ldst_info_t *info = get_irn_link(load);
	ir_node *mem, *ptr, *new_node;
	ir_entity *ent;
	unsigned res = 0;

	/* do NOT touch volatile loads for now */
	if (get_Load_volatility(load) == volatility_is_volatile)
		return 0;

	/* the address of the load to be optimized */
	ptr = get_Load_ptr(load);

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

			/* FIXME: works with the current FE, but better use the base */
727
			if (is_Alloc(skip_Proj(mem))) {
728
729
730
731
732
733
734
735
736
737
738
				/* ok, check the types */
				ir_entity *ent    = get_Sel_entity(ptr);
				ir_type   *s_type = get_entity_type(ent);
				ir_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;
739
740
					exchange(info->projs[pn_Load_X_regular], new_r_Jmp(current_ir_graph, get_nodes_block(load)));
					info->projs[pn_Load_X_regular] = NULL;
741
742
743
					res |= CF_CHANGED;
				}
			}
744
		} else if (is_Alloc(skip_Proj(skip_Cast(ptr)))) {
745
746
747
748
749
750
751
				/* 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;
752
753
				exchange(info->projs[pn_Load_X_regular], new_r_Jmp(current_ir_graph, get_nodes_block(load)));
				info->projs[pn_Load_X_regular] = NULL;
754
755
756
757
758
759
760
761
762
763
764
				res |= CF_CHANGED;
		}
	}

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

	if (! info->projs[pn_Load_res] && ! info->projs[pn_Load_X_except]) {
		/* a Load which value is neither used nor exception checked, remove it */
		exchange(info->projs[pn_Load_M], mem);

765
766
767
768
769
		if (info->projs[pn_Load_X_regular]) {
			/* should not happen, but if it does, remove it */
			exchange(info->projs[pn_Load_X_regular], new_r_Jmp(current_ir_graph, get_nodes_block(load)));
			res |= CF_CHANGED;
		}
770
		kill_node(load);
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
		reduce_adr_usage(ptr);
		return res | DF_CHANGED;
	}

	/* Load from a constant polymorphic field, where we can resolve
	   polymorphism. */
	new_node = transform_node_Load(load);
	if (new_node != load) {
		if (info->projs[pn_Load_M]) {
			exchange(info->projs[pn_Load_M], mem);
			info->projs[pn_Load_M] = NULL;
		}
		if (info->projs[pn_Load_X_except]) {
			exchange(info->projs[pn_Load_X_except], new_Bad());
			info->projs[pn_Load_X_except] = NULL;
786
787
788
789
790
791
			res |= CF_CHANGED;
		}
		if (info->projs[pn_Load_X_regular]) {
			exchange(info->projs[pn_Load_X_regular], new_r_Jmp(current_ir_graph, get_nodes_block(load)));
			info->projs[pn_Load_X_regular] = NULL;
			res |= CF_CHANGED;
792
793
794
795
		}
		if (info->projs[pn_Load_res])
			exchange(info->projs[pn_Load_res], new_node);

796
		kill_node(load);
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
		reduce_adr_usage(ptr);
		return res | DF_CHANGED;
	}

	/* check if we can determine the entity that will be loaded */
	ent = find_constant_entity(ptr);
	if (ent) {
		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;
				res |= CF_CHANGED;
			}
815
816
817
818
819
			if (info->projs[pn_Load_X_regular]) {
				exchange(info->projs[pn_Load_X_regular], new_r_Jmp(current_ir_graph, get_nodes_block(load)));
				info->projs[pn_Load_X_regular] = NULL;
				res |= CF_CHANGED;
			}
820

Michael Beck's avatar
Michael Beck committed
821
822
823
824
825
826
827
828
829
830
831
			if (variability_constant == get_entity_variability(ent)) {
				if (is_atomic_entity(ent)) {
					/* Might not be atomic after
					   lowering of Sels.  In this
					   case we could also load, but
					   it's more complicated. */
					/* more simpler case: we load the content of a constant value:
					 * replace it by the constant itself
					 */

					/* no memory */
832
833
834
835
					if (info->projs[pn_Load_M]) {
						exchange(info->projs[pn_Load_M], mem);
						res |= DF_CHANGED;
					}
Michael Beck's avatar
Michael Beck committed
836
					/* no result :-) */
837
					if (info->projs[pn_Load_res]) {
Michael Beck's avatar
Michael Beck committed
838
839
840
841
842
843
844
						if (is_atomic_entity(ent)) {
							ir_node *c = copy_const_value(get_irn_dbg_info(load), get_atomic_ent_value(ent));

							DBG_OPT_RC(load, c);
							exchange(info->projs[pn_Load_res], c);
							res |= DF_CHANGED;
						}
845
					}
846
					kill_node(load);
847
848
849
					reduce_adr_usage(ptr);
					return res;
				} else {
850
851
852
853
854
855
856
					ir_node *c = NULL;
					if (ent->has_initializer) {
						/* new style initializer */
						c = find_compound_ent_value(ptr);
					} else {
						/* old style initializer */
						compound_graph_path *path = get_accessed_path(ptr);
Michael Beck's avatar
Michael Beck committed
857

858
859
						if (path) {
							assert(is_proper_compound_graph_path(path, get_compound_graph_path_length(path)-1));
Michael Beck's avatar
Michael Beck committed
860

861
862
863
864
865
							c = get_compound_ent_value_by_path(ent, path);
							free_compound_graph_path(path);
						}
					}
					if (c != NULL) {
Michael Beck's avatar
Michael Beck committed
866
867
868
869
870
871
872
873
						if (info->projs[pn_Load_M]) {
							exchange(info->projs[pn_Load_M], mem);
							res |= DF_CHANGED;
						}
						if (info->projs[pn_Load_res]) {
							exchange(info->projs[pn_Load_res], copy_const_value(get_irn_dbg_info(load), c));
							res |= DF_CHANGED;
						}
874
						kill_node(load);
Michael Beck's avatar
Michael Beck committed
875
876
877
878
879
880
881
882
						reduce_adr_usage(ptr);
						return res;
					} else {
						/*  We can not determine a correct access path.  E.g., in jack, we load
						a byte from an object to generate an exception.   Happens in test program
						Reflectiontest.
						printf(">>>>>>>>>>>>> Found access to constant entity %s in function %s\n", get_entity_name(ent),
						get_entity_name(get_irg_entity(current_ir_graph)));
883
884
						ir_printf("  load: %+F\n", load);
						ir_printf("  ptr:  %+F\n", ptr);
Michael Beck's avatar
Michael Beck committed
885
886
						*/
					}
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
				}
			}
		}
	}

	/* 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_n_uses(ptr) <= 1)
		return res;

	/*
	 * follow the memory chain as long as there are only Loads
	 * and try to replace current Load or Store by a previous one.
	 * Note that in unreachable loops it might happen that we reach
	 * load again, as well as we can fall into a cycle.
	 * We break such cycles using a special visited flag.
	 */
	INC_MASTER();
	res = follow_Mem_chain(load, skip_Proj(mem));
	return res;
}  /* optimize_load */
Michael Beck's avatar
Michael Beck committed
908

909
910
911
912
913
914
915
916
917
/**
 * Check whether a value of mode new_mode would completely overwrite a value
 * of mode old_mode in memory.
 */
static int is_completely_overwritten(ir_mode *old_mode, ir_mode *new_mode)
{
	return get_mode_size_bits(new_mode) >= get_mode_size_bits(old_mode);
}  /* is_completely_overwritten */

Michael Beck's avatar
Michael Beck committed
918
/**
919
 * follow the memory chain as long as there are only Loads and alias free Stores.
Michael Beck's avatar
Michael Beck committed
920
921
922
 *
 * INC_MASTER() must be called before dive into
 */
923
924
925
926
927
928
929
930
931
static unsigned follow_Mem_chain_for_Store(ir_node *store, ir_node *curr) {
	unsigned res = 0;
	ldst_info_t *info = get_irn_link(store);
	ir_node *pred;
	ir_node *ptr = get_Store_ptr(store);
	ir_node *mem = get_Store_mem(store);
	ir_node *value = get_Store_value(store);
	ir_mode *mode  = get_irn_mode(value);
	ir_node *block = get_nodes_block(store);
932
	ir_node *mblk  = get_Block_MacroBlock(block);
933
934
935
936
937
938
939
940
941

	for (pred = curr; pred != store;) {
		ldst_info_t *pred_info = get_irn_link(pred);

		/*
		 * 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 *(ir_type1 *)p = a; *(ir_type2 *)p = b ...
942
943
		 * However, if the mode that is written have a bigger  or equal size the the old
		 * one, the old value is completely overwritten and can be killed ...
944
		 */
945
946
		if (is_Store(pred) && get_Store_ptr(pred) == ptr &&
		    get_nodes_MacroBlock(pred) == mblk &&
947
		    is_completely_overwritten(get_irn_mode(get_Store_value(pred)), mode)) {
948
			/*
Michael Beck's avatar
Michael Beck committed
949
			 * a Store after a Store in the same MacroBlock -- a write after write.
950
951
952
953
954
955
			 * 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);
956
				exchange(pred_info->projs[pn_Store_M], get_Store_mem(pred));
957
				kill_node(pred);
958
959
960
				reduce_adr_usage(ptr);
				return DF_CHANGED;
			}
961
		} else if (is_Load(pred) && get_Load_ptr(pred) == ptr &&
962
963
		           value == pred_info->projs[pn_Load_res]) {
			/*
964
965
966
967
			 * a Store of a value just loaded from the same address
			 * -- a write after read.
			 * We may remove the Store, if it does not have an exception
			 * handler.
968
969
970
			 */
			if (! info->projs[pn_Store_X_except]) {
				DBG_OPT_WAR(store, pred);
971
				exchange(info->projs[pn_Store_M], mem);
972
				kill_node(store);
973
974
975
976
977
				reduce_adr_usage(ptr);
				return DF_CHANGED;
			}
		}

978
		if (is_Store(pred)) {
979
980
981
982
983
			/* check if we can pass thru this store */
			ir_alias_relation rel = get_alias_relation(
				current_ir_graph,
				get_Store_ptr(pred),
				get_irn_mode(get_Store_value(pred)),
984
				ptr, mode);
985
			/* if the might be an alias, we cannot pass this Store */
Michael Beck's avatar
Michael Beck committed
986
			if (rel != ir_no_alias)
987
988
				break;
			pred = skip_Proj(get_Store_mem(pred));
989
		} else if (is_Load(pred)) {
990
991
992
			ir_alias_relation rel = get_alias_relation(
				current_ir_graph, get_Load_ptr(pred), get_Load_mode(pred),
				ptr, mode);
Michael Beck's avatar
Michael Beck committed
993
			if (rel != ir_no_alias)
994
995
				break;

996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
			pred = skip_Proj(get_Load_mem(pred));
		} else {
			/* follow only Load chains */
			break;
		}

		/* check for cycles */
		if (NODE_VISITED(pred_info))
			break;
		MARK_NODE(pred_info);
	}

1008
	if (is_Sync(pred)) {
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
		int i;

		/* handle all Sync predecessors */
		for (i = get_Sync_n_preds(pred) - 1; i >= 0; --i) {
			res |= follow_Mem_chain_for_Store(store, skip_Proj(get_Sync_pred(pred, i)));
			if (res)
				break;
		}
	}
	return res;
}  /* follow_Mem_chain_for_Store */
Michael Beck's avatar
Michael Beck committed
1020
1021
1022

/**
 * optimize a Store
1023
1024
 *
 * @param store  the Store node
Michael Beck's avatar
Michael Beck committed
1025
 */
1026
1027
static unsigned optimize_store(ir_node *store) {
	ir_node *ptr, *mem;
Michael Beck's avatar
Michael Beck committed
1028

1029
1030
	if (get_Store_volatility(store) == volatility_is_volatile)
		return 0;
Michael Beck's avatar
Michael Beck committed
1031

1032
	ptr = get_Store_ptr(store);
1033

1034
1035
1036
1037
	/* Check, if the address of this Store is used more than once.
	 * If not, this Store cannot be removed in any case. */
	if (get_irn_n_uses(ptr) <= 1)
		return 0;
1038

1039
	mem = get_Store_mem(store);
Michael Beck's avatar
Michael Beck committed
1040

1041
1042
	/* follow the memory chain as long as there are only Loads */
	INC_MASTER();
Michael Beck's avatar
Michael Beck committed
1043

1044
1045
	return follow_Mem_chain_for_Store(store, skip_Proj(mem));
}  /* optimize_store */
Michael Beck's avatar
Michael Beck committed
1046

Michael Beck's avatar
Michael Beck committed
1047
/**
1048
 * walker, optimizes Phi after Stores to identical places:
Michael Beck's avatar
Michael Beck committed
1049
 * Does the following optimization:
1050
 * @verbatim
Michael Beck's avatar
Michael Beck committed
1051
1052
1053
 *
 *   val1   val2   val3          val1  val2  val3
 *    |      |      |               \    |    /
1054
 *  Store  Store  Store              \   |   /
1055
 *      \    |    /                   PhiData
Michael Beck's avatar
Michael Beck committed
1056
 *       \   |   /                       |
1057
 *        \  |  /                      Store
1058
 *          PhiM
Michael Beck's avatar
Michael Beck committed
1059
 *
1060
 * @endverbatim
1061
1062
 * This reduces the number of stores and allows for predicated execution.
 * Moves Stores back to the end of a function which may be bad.
Michael Beck's avatar
Michael Beck committed
1063
 *
1064
 * This is only possible if the predecessor blocks have only one successor.
Michael Beck's avatar
Michael Beck committed
1065
 */
1066
static unsigned optimize_phi(ir_node *phi, walk_env_t *wenv)
Michael Beck's avatar
Michael Beck committed
1067
{
1068
1069
1070
	int i, n;
	ir_node *store, *old_store, *ptr, *block, *phi_block, *phiM, *phiD, *exc, *projM;
	ir_mode *mode;
1071
	ir_node **inM, **inD, **projMs;
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
	int *idx;
	dbg_info *db = NULL;
	ldst_info_t *info;
	block_info_t *bl_info;
	unsigned res = 0;

	/* 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;

Matthias Braun's avatar
Matthias Braun committed
1086
1087
1088
1089
1090
1091
	/* must be only one user */
	projM = get_Phi_pred(phi, 0);
	if (get_irn_n_edges(projM) != 1)
		return 0;

	store = skip_Proj(projM);
1092
	old_store = store;
1093
	if (!is_Store(store))
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
		return 0;

	block = get_nodes_block(store);

	/* abort on dead blocks */
	if (is_Block_dead(block))
		return 0;

	/* check if the block is post dominated by Phi-block
	   and has no exception exit */
	bl_info = get_irn_link(block);
	if (bl_info->flags & BLOCK_HAS_EXC)
		return 0;

	phi_block = get_nodes_block(phi);
1109
	if (! block_strictly_postdominates(phi_block, block))
1110
1111
1112
1113
1114
1115
1116
1117
1118
		return 0;

	/* 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) {
Matthias Braun's avatar
Matthias Braun committed
1119
1120
1121
1122
		ir_node *pred = get_Phi_pred(phi, i);

		if (get_irn_n_edges(pred) != 1)
			return 0;
1123

Matthias Braun's avatar
Matthias Braun committed
1124
		pred = skip_Proj(pred);
1125
		if (!is_Store(pred))
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
			return 0;

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

		info = get_irn_link(pred);

		/* check, if all stores have the same exception flow */
		if (exc != info->exc_block)
			return 0;

		/* abort on dead blocks */
		block = get_nodes_block(pred);
		if (is_Block_dead(block))
			return 0;

		/* check if the block is post dominated by Phi-block
		   and has no exception exit. Note that block must be different from
		   Phi-block, else we would move a Store from end End of a block to its
		   Start... */
		bl_info = get_irn_link(block);
		if (bl_info->flags & BLOCK_HAS_EXC)
			return 0;
		if (block == phi_block || ! block_postdominates(phi_block, block))
			return 0;
	}

	/*
	 * ok, when we are here, we found all predecessors of a Phi that
	 * are Stores to the same address and size. 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 |             \   |   /
	 *      \     |     /                   PhiData
	 *       \    |    /                       |
	 *        \   |   /                       Str
	 *           PhiM
	 *
	 * Is only allowed if the predecessor blocks have only one successor.
	 */

1170
	NEW_ARR_A(ir_node *, projMs, n);
1171
1172
1173
1174
1175
1176
1177
1178
	NEW_ARR_A(ir_node *, inM, n);
	NEW_ARR_A(ir_node *, inD, n);
	NEW_ARR_A(int, idx, n);

	/* Prepare: Collect all Store nodes.  We must do this
	   first because we otherwise may loose a store when exchanging its
	   memory Proj.
	 */
1179
1180
1181
	for (i = n - 1; i >= 0; --i) {
		ir_node *store;

1182
		projMs[i] = get_Phi_pred(phi, i);
1183
		assert(is_Proj(projMs[i]));
1184

1185
1186
		store = get_Proj_pred(projMs[i]);
		info  = get_irn_link(store);
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199

		inM[i] = get_Store_mem(store);
		inD[i] = get_Store_value(store);
		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);

1200
	/* rewire memory and kill the node */
1201
	for (i = n - 1; i >= 0; --i) {
1202
		ir_node *proj  = projMs[i];
1203

1204
1205
1206
1207
1208
		if(is_Proj(proj)) {
			ir_node *store = get_Proj_pred(proj);
			exchange(proj, inM[i]);
			kill_node(store);
		}
1209
1210
	}

1211
1212
	/* fourth step: create the Store */
	store = new_rd_Store(db, current_ir_graph, block, phiM, ptr, phiD);
1213
#ifdef DO_CACHEOPT
1214
	co_set_irn_name(store, co_get_irn_ident(old_store));
1215
1216
#endif

1217
	projM = new_rd_Proj(NULL, current_ir_graph, block, store, mode_M, pn_Store_M);
1218

1219
	info = get_ldst_info(store, &wenv->obst);
1220
	info->projs[pn_Store_M] = projM;
Michael Beck's avatar
Michael Beck committed
1221

1222
1223
1224
	/* 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);
Michael Beck's avatar
Michael Beck committed
1225

1226
1227
1228
		info->projs[pn_Store_X_except] = projX;
		info->exc_block                = exc;
		info->exc_idx                  = idx[0];
1229

1230
1231
1232
		for (i = 0; i < n; ++i) {
			set_Block_cfgpred(exc, idx[i], projX);
		}
Michael Beck's avatar
Michael Beck committed
1233

1234
1235
1236
		if (n > 1) {
			/* the exception block should be optimized as some inputs are identical now */
		}
1237

1238
1239
		res |= CF_CHANGED;
	}
Michael Beck's avatar
Michael Beck committed
1240

1241
1242
	/* sixth step: replace old Phi */
	exchange(phi, projM);
Michael Beck's avatar
Michael Beck committed
1243

1244
1245
	return res | DF_CHANGED;
}  /* optimize_phi */
Michael Beck's avatar
Michael Beck committed
1246

Michael Beck's avatar
Michael Beck committed
1247
/**
Michael Beck's avatar
Michael Beck committed
1248
 * walker, do the optimizations
Michael Beck's avatar