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/* Instruction scheduling pass.  This file contains definitions used
2
   internally in the scheduler.
3
   Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998,
4
   1999, 2000, 2001, 2003, 2004, 2005, 2006, 2007
5
   Free Software Foundation, Inc.
6
 
7
This file is part of GCC.
8
 
9
GCC is free software; you can redistribute it and/or modify it under
10
the terms of the GNU General Public License as published by the Free
11
Software Foundation; either version 3, or (at your option) any later
12
version.
13
 
14
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
15
WARRANTY; without even the implied warranty of MERCHANTABILITY or
16
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
17
for more details.
18
 
19
You should have received a copy of the GNU General Public License
20
along with GCC; see the file COPYING3.  If not see
21
<http://www.gnu.org/licenses/>.  */
22
 
23
#ifndef GCC_SCHED_INT_H
24
#define GCC_SCHED_INT_H
25
 
26
/* For state_t.  */
27
#include "insn-attr.h"
28
/* For regset_head.  */
29
#include "basic-block.h"
30
/* For reg_note.  */
31
#include "rtl.h"
32
 
33
/* Pointer to data describing the current DFA state.  */
34
extern state_t curr_state;
35
 
36
/* Forward declaration.  */
37
struct ready_list;
38
 
39
/* Type to represent status of a dependence.  */
40
typedef int ds_t;
41
 
42
/* Type to represent weakness of speculative dependence.  */
43
typedef int dw_t;
44
 
45
/* Describe state of dependencies used during sched_analyze phase.  */
46
struct deps
47
{
48
  /* The *_insns and *_mems are paired lists.  Each pending memory operation
49
     will have a pointer to the MEM rtx on one list and a pointer to the
50
     containing insn on the other list in the same place in the list.  */
51
 
52
  /* We can't use add_dependence like the old code did, because a single insn
53
     may have multiple memory accesses, and hence needs to be on the list
54
     once for each memory access.  Add_dependence won't let you add an insn
55
     to a list more than once.  */
56
 
57
  /* An INSN_LIST containing all insns with pending read operations.  */
58
  rtx pending_read_insns;
59
 
60
  /* An EXPR_LIST containing all MEM rtx's which are pending reads.  */
61
  rtx pending_read_mems;
62
 
63
  /* An INSN_LIST containing all insns with pending write operations.  */
64
  rtx pending_write_insns;
65
 
66
  /* An EXPR_LIST containing all MEM rtx's which are pending writes.  */
67
  rtx pending_write_mems;
68
 
69
  /* Indicates the combined length of the two pending lists.  We must prevent
70
     these lists from ever growing too large since the number of dependencies
71
     produced is at least O(N*N), and execution time is at least O(4*N*N), as
72
     a function of the length of these pending lists.  */
73
  int pending_lists_length;
74
 
75
  /* Length of the pending memory flush list. Large functions with no
76
     calls may build up extremely large lists.  */
77
  int pending_flush_length;
78
 
79
  /* The last insn upon which all memory references must depend.
80
     This is an insn which flushed the pending lists, creating a dependency
81
     between it and all previously pending memory references.  This creates
82
     a barrier (or a checkpoint) which no memory reference is allowed to cross.
83
 
84
     This includes all non constant CALL_INSNs.  When we do interprocedural
85
     alias analysis, this restriction can be relaxed.
86
     This may also be an INSN that writes memory if the pending lists grow
87
     too large.  */
88
  rtx last_pending_memory_flush;
89
 
90
  /* A list of the last function calls we have seen.  We use a list to
91
     represent last function calls from multiple predecessor blocks.
92
     Used to prevent register lifetimes from expanding unnecessarily.  */
93
  rtx last_function_call;
94
 
95
  /* A list of insns which use a pseudo register that does not already
96
     cross a call.  We create dependencies between each of those insn
97
     and the next call insn, to ensure that they won't cross a call after
98
     scheduling is done.  */
99
  rtx sched_before_next_call;
100
 
101
  /* Used to keep post-call pseudo/hard reg movements together with
102
     the call.  */
103
  enum { not_post_call, post_call, post_call_initial } in_post_call_group_p;
104
 
105
  /* Set to the tail insn of the outermost libcall block.
106
 
107
     When nonzero, we will mark each insn processed by sched_analyze_insn
108
     with SCHED_GROUP_P to ensure libcalls are scheduled as a unit.  */
109
  rtx libcall_block_tail_insn;
110
 
111
  /* The maximum register number for the following arrays.  Before reload
112
     this is max_reg_num; after reload it is FIRST_PSEUDO_REGISTER.  */
113
  int max_reg;
114
 
115
  /* Element N is the next insn that sets (hard or pseudo) register
116
     N within the current basic block; or zero, if there is no
117
     such insn.  Needed for new registers which may be introduced
118
     by splitting insns.  */
119
  struct deps_reg
120
    {
121
      rtx uses;
122
      rtx sets;
123
      rtx clobbers;
124
      int uses_length;
125
      int clobbers_length;
126
    } *reg_last;
127
 
128
  /* Element N is set for each register that has any nonzero element
129
     in reg_last[N].{uses,sets,clobbers}.  */
130
  regset_head reg_last_in_use;
131
 
132
  /* Element N is set for each register that is conditionally set.  */
133
  regset_head reg_conditional_sets;
134
};
135
 
136
/* This structure holds some state of the current scheduling pass, and
137
   contains some function pointers that abstract out some of the non-generic
138
   functionality from functions such as schedule_block or schedule_insn.
139
   There is one global variable, current_sched_info, which points to the
140
   sched_info structure currently in use.  */
141
struct sched_info
142
{
143
  /* Add all insns that are initially ready to the ready list.  Called once
144
     before scheduling a set of insns.  */
145
  void (*init_ready_list) (void);
146
  /* Called after taking an insn from the ready list.  Returns nonzero if
147
     this insn can be scheduled, nonzero if we should silently discard it.  */
148
  int (*can_schedule_ready_p) (rtx);
149
  /* Return nonzero if there are more insns that should be scheduled.  */
150
  int (*schedule_more_p) (void);
151
  /* Called after an insn has all its hard dependencies resolved.
152
     Adjusts status of instruction (which is passed through second parameter)
153
     to indicate if instruction should be moved to the ready list or the
154
     queue, or if it should silently discard it (until next resolved
155
     dependence).  */
156
  ds_t (*new_ready) (rtx, ds_t);
157
  /* Compare priority of two insns.  Return a positive number if the second
158
     insn is to be preferred for scheduling, and a negative one if the first
159
     is to be preferred.  Zero if they are equally good.  */
160
  int (*rank) (rtx, rtx);
161
  /* Return a string that contains the insn uid and optionally anything else
162
     necessary to identify this insn in an output.  It's valid to use a
163
     static buffer for this.  The ALIGNED parameter should cause the string
164
     to be formatted so that multiple output lines will line up nicely.  */
165
  const char *(*print_insn) (rtx, int);
166
  /* Return nonzero if an insn should be included in priority
167
     calculations.  */
168
  int (*contributes_to_priority) (rtx, rtx);
169
  /* Called when computing dependencies for a JUMP_INSN.  This function
170
     should store the set of registers that must be considered as set by
171
     the jump in the regset.  */
172
  void (*compute_jump_reg_dependencies) (rtx, regset, regset, regset);
173
 
174
  /* The boundaries of the set of insns to be scheduled.  */
175
  rtx prev_head, next_tail;
176
 
177
  /* Filled in after the schedule is finished; the first and last scheduled
178
     insns.  */
179
  rtx head, tail;
180
 
181
  /* If nonzero, enables an additional sanity check in schedule_block.  */
182
  unsigned int queue_must_finish_empty:1;
183
  /* Nonzero if we should use cselib for better alias analysis.  This
184
     must be 0 if the dependency information is used after sched_analyze
185
     has completed, e.g. if we're using it to initialize state for successor
186
     blocks in region scheduling.  */
187
  unsigned int use_cselib:1;
188
 
189
  /* Maximum priority that has been assigned to an insn.  */
190
  int sched_max_insns_priority;
191
 
192
  /* Hooks to support speculative scheduling.  */
193
 
194
  /* Called to notify frontend that instruction is being added (second
195
     parameter == 0) or removed (second parameter == 1).  */
196
  void (*add_remove_insn) (rtx, int);
197
 
198
  /* Called to notify frontend that instruction is being scheduled.
199
     The first parameter - instruction to scheduled, the second parameter -
200
     last scheduled instruction.  */
201
  void (*begin_schedule_ready) (rtx, rtx);
202
 
203
  /* Called to notify frontend, that new basic block is being added.
204
     The first parameter - new basic block.
205
     The second parameter - block, after which new basic block is being added,
206
     or EXIT_BLOCK_PTR, if recovery block is being added,
207
     or NULL, if standalone block is being added.  */
208
  void (*add_block) (basic_block, basic_block);
209
 
210
  /* If the second parameter is not NULL, return nonnull value, if the
211
     basic block should be advanced.
212
     If the second parameter is NULL, return the next basic block in EBB.
213
     The first parameter is the current basic block in EBB.  */
214
  basic_block (*advance_target_bb) (basic_block, rtx);
215
 
216
  /* Called after blocks were rearranged due to movement of jump instruction.
217
     The first parameter - index of basic block, in which jump currently is.
218
     The second parameter - index of basic block, in which jump used
219
     to be.
220
     The third parameter - index of basic block, that follows the second
221
     parameter.  */
222
  void (*fix_recovery_cfg) (int, int, int);
223
 
224
#ifdef ENABLE_CHECKING
225
  /* If the second parameter is zero, return nonzero, if block is head of the
226
     region.
227
     If the second parameter is nonzero, return nonzero, if block is leaf of
228
     the region.
229
     global_live_at_start should not change in region heads and
230
     global_live_at_end should not change in region leafs due to scheduling.  */
231
  int (*region_head_or_leaf_p) (basic_block, int);
232
#endif
233
 
234
  /* ??? FIXME: should use straight bitfields inside sched_info instead of
235
     this flag field.  */
236
  unsigned int flags;
237
};
238
 
239
/* This structure holds description of the properties for speculative
240
   scheduling.  */
241
struct spec_info_def
242
{
243
  /* Holds types of allowed speculations: BEGIN_{DATA|CONTROL},
244
     BE_IN_{DATA_CONTROL}.  */
245
  int mask;
246
 
247
  /* A dump file for additional information on speculative scheduling.  */
248
  FILE *dump;
249
 
250
  /* Minimal cumulative weakness of speculative instruction's
251
     dependencies, so that insn will be scheduled.  */
252
  dw_t weakness_cutoff;
253
 
254
  /* Flags from the enum SPEC_SCHED_FLAGS.  */
255
  int flags;
256
};
257
typedef struct spec_info_def *spec_info_t;
258
 
259
extern struct sched_info *current_sched_info;
260
 
261
/* Indexed by INSN_UID, the collection of all data associated with
262
   a single instruction.  */
263
 
264
struct haifa_insn_data
265
{
266
  /* A list of insns which depend on the instruction.  Unlike LOG_LINKS,
267
     it represents forward dependencies.  */
268
  rtx depend;
269
 
270
  /* A list of scheduled producers of the instruction.  Links are being moved
271
     from LOG_LINKS to RESOLVED_DEPS during scheduling.  */
272
  rtx resolved_deps;
273
 
274
  /* The line number note in effect for each insn.  For line number
275
     notes, this indicates whether the note may be reused.  */
276
  rtx line_note;
277
 
278
  /* Logical uid gives the original ordering of the insns.  */
279
  int luid;
280
 
281
  /* A priority for each insn.  */
282
  int priority;
283
 
284
  /* The number of incoming edges in the forward dependency graph.
285
     As scheduling proceeds, counts are decreased.  An insn moves to
286
     the ready queue when its counter reaches zero.  */
287
  int dep_count;
288
 
289
  /* Number of instructions referring to this insn.  */
290
  int ref_count;
291
 
292
  /* The minimum clock tick at which the insn becomes ready.  This is
293
     used to note timing constraints for the insns in the pending list.  */
294
  int tick;
295
 
296
  /* INTER_TICK is used to adjust INSN_TICKs of instructions from the
297
     subsequent blocks in a region.  */
298
  int inter_tick;
299
 
300
  /* See comment on QUEUE_INDEX macro in haifa-sched.c.  */
301
  int queue_index;
302
 
303
  short cost;
304
 
305
  /* This weight is an estimation of the insn's contribution to
306
     register pressure.  */
307
  short reg_weight;
308
 
309
  /* Some insns (e.g. call) are not allowed to move across blocks.  */
310
  unsigned int cant_move : 1;
311
 
312
  /* Set if there's DEF-USE dependence between some speculatively
313
     moved load insn and this one.  */
314
  unsigned int fed_by_spec_load : 1;
315
  unsigned int is_load_insn : 1;
316
 
317
  /* Nonzero if priority has been computed already.  */
318
  unsigned int priority_known : 1;
319
 
320
  /* Nonzero if instruction has internal dependence
321
     (e.g. add_dependence was invoked with (insn == elem)).  */
322
  unsigned int has_internal_dep : 1;
323
 
324
  /* What speculations are necessary to apply to schedule the instruction.  */
325
  ds_t todo_spec;
326
  /* What speculations were already applied.  */
327
  ds_t done_spec;
328
  /* What speculations are checked by this instruction.  */
329
  ds_t check_spec;
330
 
331
  /* Recovery block for speculation checks.  */
332
  basic_block recovery_block;
333
 
334
  /* Original pattern of the instruction.  */
335
  rtx orig_pat;
336
};
337
 
338
extern struct haifa_insn_data *h_i_d;
339
/* Used only if (current_sched_info->flags & USE_GLAT) != 0.
340
   These regsets store global_live_at_{start, end} information
341
   for each basic block.  */
342
extern regset *glat_start, *glat_end;
343
 
344
/* Accessor macros for h_i_d.  There are more in haifa-sched.c and
345
   sched-rgn.c.  */
346
#define INSN_DEPEND(INSN)       (h_i_d[INSN_UID (INSN)].depend)
347
#define RESOLVED_DEPS(INSN)     (h_i_d[INSN_UID (INSN)].resolved_deps)
348
#define INSN_LUID(INSN)         (h_i_d[INSN_UID (INSN)].luid)
349
#define CANT_MOVE(insn)         (h_i_d[INSN_UID (insn)].cant_move)
350
#define INSN_DEP_COUNT(INSN)    (h_i_d[INSN_UID (INSN)].dep_count)
351
#define INSN_PRIORITY(INSN)     (h_i_d[INSN_UID (INSN)].priority)
352
#define INSN_PRIORITY_KNOWN(INSN) (h_i_d[INSN_UID (INSN)].priority_known)
353
#define INSN_COST(INSN)         (h_i_d[INSN_UID (INSN)].cost)
354
#define INSN_REG_WEIGHT(INSN)   (h_i_d[INSN_UID (INSN)].reg_weight)
355
#define HAS_INTERNAL_DEP(INSN)  (h_i_d[INSN_UID (INSN)].has_internal_dep)
356
#define TODO_SPEC(INSN)         (h_i_d[INSN_UID (INSN)].todo_spec)
357
#define DONE_SPEC(INSN)         (h_i_d[INSN_UID (INSN)].done_spec)
358
#define CHECK_SPEC(INSN)        (h_i_d[INSN_UID (INSN)].check_spec)
359
#define RECOVERY_BLOCK(INSN)    (h_i_d[INSN_UID (INSN)].recovery_block)
360
#define ORIG_PAT(INSN)          (h_i_d[INSN_UID (INSN)].orig_pat)
361
 
362
/* INSN is either a simple or a branchy speculation check.  */
363
#define IS_SPECULATION_CHECK_P(INSN) (RECOVERY_BLOCK (INSN) != NULL)
364
 
365
/* INSN is a speculation check that will simply reexecute the speculatively
366
   scheduled instruction if the speculation fails.  */
367
#define IS_SPECULATION_SIMPLE_CHECK_P(INSN) \
368
  (RECOVERY_BLOCK (INSN) == EXIT_BLOCK_PTR)
369
 
370
/* INSN is a speculation check that will branch to RECOVERY_BLOCK if the
371
   speculation fails.  Insns in that block will reexecute the speculatively
372
   scheduled code and then will return immediately after INSN thus preserving
373
   semantics of the program.  */
374
#define IS_SPECULATION_BRANCHY_CHECK_P(INSN) \
375
  (RECOVERY_BLOCK (INSN) != NULL && RECOVERY_BLOCK (INSN) != EXIT_BLOCK_PTR)
376
 
377
/* DEP_STATUS of the link encapsulates information, that is needed for
378
   speculative scheduling.  Namely, it is 4 integers in the range
379
   [0, MAX_DEP_WEAK] and 3 bits.
380
   The integers correspond to the probability of the dependence to *not*
381
   exist, it is the probability, that overcoming of this dependence will
382
   not be followed by execution of the recovery code.  Nevertheless,
383
   whatever high the probability of success is, recovery code should still
384
   be generated to preserve semantics of the program.  To find a way to
385
   get/set these integers, please refer to the {get, set}_dep_weak ()
386
   functions in sched-deps.c .
387
   The 3 bits in the DEP_STATUS correspond to 3 dependence types: true-,
388
   output- and anti- dependence.  It is not enough for speculative scheduling
389
   to know just the major type of all the dependence between two instructions,
390
   as only true dependence can be overcome.
391
   There also is the 4-th bit in the DEP_STATUS (HARD_DEP), that is reserved
392
   for using to describe instruction's status.  It is set whenever instruction
393
   has at least one dependence, that cannot be overcome.
394
   See also: check_dep_status () in sched-deps.c .  */
395
#define DEP_STATUS(LINK) XINT (LINK, 2)
396
 
397
/* We exclude sign bit.  */
398
#define BITS_PER_DEP_STATUS (HOST_BITS_PER_INT - 1)
399
 
400
/* First '4' stands for 3 dep type bits and HARD_DEP bit.
401
   Second '4' stands for BEGIN_{DATA, CONTROL}, BE_IN_{DATA, CONTROL}
402
   dep weakness.  */
403
#define BITS_PER_DEP_WEAK ((BITS_PER_DEP_STATUS - 4) / 4)
404
 
405
/* Mask of speculative weakness in dep_status.  */
406
#define DEP_WEAK_MASK ((1 << BITS_PER_DEP_WEAK) - 1)
407
 
408
/* This constant means that dependence is fake with 99.999...% probability.
409
   This is the maximum value, that can appear in dep_status.
410
   Note, that we don't want MAX_DEP_WEAK to be the same as DEP_WEAK_MASK for
411
   debugging reasons.  Though, it can be set to DEP_WEAK_MASK, and, when
412
   done so, we'll get fast (mul for)/(div by) NO_DEP_WEAK.  */
413
#define MAX_DEP_WEAK (DEP_WEAK_MASK - 1)
414
 
415
/* This constant means that dependence is 99.999...% real and it is a really
416
   bad idea to overcome it (though this can be done, preserving program
417
   semantics).  */
418
#define MIN_DEP_WEAK 1
419
 
420
/* This constant represents 100% probability.
421
   E.g. it is used to represent weakness of dependence, that doesn't exist.  */
422
#define NO_DEP_WEAK (MAX_DEP_WEAK + MIN_DEP_WEAK)
423
 
424
/* Default weakness of speculative dependence.  Used when we can't say
425
   neither bad nor good about the dependence.  */
426
#define UNCERTAIN_DEP_WEAK (MAX_DEP_WEAK - MAX_DEP_WEAK / 4)
427
 
428
/* Offset for speculative weaknesses in dep_status.  */
429
enum SPEC_TYPES_OFFSETS {
430
  BEGIN_DATA_BITS_OFFSET = 0,
431
  BE_IN_DATA_BITS_OFFSET = BEGIN_DATA_BITS_OFFSET + BITS_PER_DEP_WEAK,
432
  BEGIN_CONTROL_BITS_OFFSET = BE_IN_DATA_BITS_OFFSET + BITS_PER_DEP_WEAK,
433
  BE_IN_CONTROL_BITS_OFFSET = BEGIN_CONTROL_BITS_OFFSET + BITS_PER_DEP_WEAK
434
};
435
 
436
/* The following defines provide numerous constants used to distinguish between
437
   different types of speculative dependencies.  */
438
 
439
/* Dependence can be overcome with generation of new data speculative
440
   instruction.  */
441
#define BEGIN_DATA (((ds_t) DEP_WEAK_MASK) << BEGIN_DATA_BITS_OFFSET)
442
 
443
/* This dependence is to the instruction in the recovery block, that was
444
   formed to recover after data-speculation failure.
445
   Thus, this dependence can overcome with generating of the copy of
446
   this instruction in the recovery block.  */
447
#define BE_IN_DATA (((ds_t) DEP_WEAK_MASK) << BE_IN_DATA_BITS_OFFSET)
448
 
449
/* Dependence can be overcome with generation of new control speculative
450
   instruction.  */
451
#define BEGIN_CONTROL (((ds_t) DEP_WEAK_MASK) << BEGIN_CONTROL_BITS_OFFSET)
452
 
453
/* This dependence is to the instruction in the recovery block, that was
454
   formed to recover after control-speculation failure.
455
   Thus, this dependence can be overcome with generating of the copy of
456
   this instruction in the recovery block.  */
457
#define BE_IN_CONTROL (((ds_t) DEP_WEAK_MASK) << BE_IN_CONTROL_BITS_OFFSET)
458
 
459
/* A few convenient combinations.  */
460
#define BEGIN_SPEC (BEGIN_DATA | BEGIN_CONTROL)
461
#define DATA_SPEC (BEGIN_DATA | BE_IN_DATA)
462
#define CONTROL_SPEC (BEGIN_CONTROL | BE_IN_CONTROL)
463
#define SPECULATIVE (DATA_SPEC | CONTROL_SPEC)
464
#define BE_IN_SPEC (BE_IN_DATA | BE_IN_CONTROL)
465
 
466
/* Constants, that are helpful in iterating through dep_status.  */
467
#define FIRST_SPEC_TYPE BEGIN_DATA
468
#define LAST_SPEC_TYPE BE_IN_CONTROL
469
#define SPEC_TYPE_SHIFT BITS_PER_DEP_WEAK
470
 
471
/* Dependence on instruction can be of multiple types
472
   (e.g. true and output). This fields enhance REG_NOTE_KIND information
473
   of the dependence.  */
474
#define DEP_TRUE (((ds_t) 1) << (BE_IN_CONTROL_BITS_OFFSET + BITS_PER_DEP_WEAK))
475
#define DEP_OUTPUT (DEP_TRUE << 1)
476
#define DEP_ANTI (DEP_OUTPUT << 1)
477
 
478
#define DEP_TYPES (DEP_TRUE | DEP_OUTPUT | DEP_ANTI)
479
 
480
/* Instruction has non-speculative dependence.  This bit represents the
481
   property of an instruction - not the one of a dependence.
482
   Therefore, it can appear only in TODO_SPEC field of an instruction.  */
483
#define HARD_DEP (DEP_ANTI << 1)
484
 
485
/* This represents the results of calling sched-deps.c functions,
486
   which modify dependencies.  Possible choices are: a dependence
487
   is already present and nothing has been changed; a dependence type
488
   has been changed; brand new dependence has been created.  */
489
enum DEPS_ADJUST_RESULT {
490
  DEP_PRESENT = 1,
491
  DEP_CHANGED = 2,
492
  DEP_CREATED = 3
493
};
494
 
495
/* Represents the bits that can be set in the flags field of the
496
   sched_info structure.  */
497
enum SCHED_FLAGS {
498
  /* If set, generate links between instruction as DEPS_LIST.
499
     Otherwise, generate usual INSN_LIST links.  */
500
  USE_DEPS_LIST = 1,
501
  /* Perform data or control (or both) speculation.
502
     Results in generation of data and control speculative dependencies.
503
     Requires USE_DEPS_LIST set.  */
504
  DO_SPECULATION = USE_DEPS_LIST << 1,
505
  SCHED_RGN = DO_SPECULATION << 1,
506
  SCHED_EBB = SCHED_RGN << 1,
507
  /* Detach register live information from basic block headers.
508
     This is necessary to invoke functions, that change CFG (e.g. split_edge).
509
     Requires USE_GLAT.  */
510
  DETACH_LIFE_INFO = SCHED_EBB << 1,
511
  /* Save register live information from basic block headers to
512
     glat_{start, end} arrays.  */
513
  USE_GLAT = DETACH_LIFE_INFO << 1
514
};
515
 
516
enum SPEC_SCHED_FLAGS {
517
  COUNT_SPEC_IN_CRITICAL_PATH = 1,
518
  PREFER_NON_DATA_SPEC = COUNT_SPEC_IN_CRITICAL_PATH << 1,
519
  PREFER_NON_CONTROL_SPEC = PREFER_NON_DATA_SPEC << 1
520
};
521
 
522
#define NOTE_NOT_BB_P(NOTE) (NOTE_P (NOTE) && (NOTE_LINE_NUMBER (NOTE)  \
523
                                               != NOTE_INSN_BASIC_BLOCK))
524
 
525
extern FILE *sched_dump;
526
extern int sched_verbose;
527
 
528
/* Exception Free Loads:
529
 
530
   We define five classes of speculative loads: IFREE, IRISKY,
531
   PFREE, PRISKY, and MFREE.
532
 
533
   IFREE loads are loads that are proved to be exception-free, just
534
   by examining the load insn.  Examples for such loads are loads
535
   from TOC and loads of global data.
536
 
537
   IRISKY loads are loads that are proved to be exception-risky,
538
   just by examining the load insn.  Examples for such loads are
539
   volatile loads and loads from shared memory.
540
 
541
   PFREE loads are loads for which we can prove, by examining other
542
   insns, that they are exception-free.  Currently, this class consists
543
   of loads for which we are able to find a "similar load", either in
544
   the target block, or, if only one split-block exists, in that split
545
   block.  Load2 is similar to load1 if both have same single base
546
   register.  We identify only part of the similar loads, by finding
547
   an insn upon which both load1 and load2 have a DEF-USE dependence.
548
 
549
   PRISKY loads are loads for which we can prove, by examining other
550
   insns, that they are exception-risky.  Currently we have two proofs for
551
   such loads.  The first proof detects loads that are probably guarded by a
552
   test on the memory address.  This proof is based on the
553
   backward and forward data dependence information for the region.
554
   Let load-insn be the examined load.
555
   Load-insn is PRISKY iff ALL the following hold:
556
 
557
   - insn1 is not in the same block as load-insn
558
   - there is a DEF-USE dependence chain (insn1, ..., load-insn)
559
   - test-insn is either a compare or a branch, not in the same block
560
     as load-insn
561
   - load-insn is reachable from test-insn
562
   - there is a DEF-USE dependence chain (insn1, ..., test-insn)
563
 
564
   This proof might fail when the compare and the load are fed
565
   by an insn not in the region.  To solve this, we will add to this
566
   group all loads that have no input DEF-USE dependence.
567
 
568
   The second proof detects loads that are directly or indirectly
569
   fed by a speculative load.  This proof is affected by the
570
   scheduling process.  We will use the flag  fed_by_spec_load.
571
   Initially, all insns have this flag reset.  After a speculative
572
   motion of an insn, if insn is either a load, or marked as
573
   fed_by_spec_load, we will also mark as fed_by_spec_load every
574
   insn1 for which a DEF-USE dependence (insn, insn1) exists.  A
575
   load which is fed_by_spec_load is also PRISKY.
576
 
577
   MFREE (maybe-free) loads are all the remaining loads. They may be
578
   exception-free, but we cannot prove it.
579
 
580
   Now, all loads in IFREE and PFREE classes are considered
581
   exception-free, while all loads in IRISKY and PRISKY classes are
582
   considered exception-risky.  As for loads in the MFREE class,
583
   these are considered either exception-free or exception-risky,
584
   depending on whether we are pessimistic or optimistic.  We have
585
   to take the pessimistic approach to assure the safety of
586
   speculative scheduling, but we can take the optimistic approach
587
   by invoking the -fsched_spec_load_dangerous option.  */
588
 
589
enum INSN_TRAP_CLASS
590
{
591
  TRAP_FREE = 0, IFREE = 1, PFREE_CANDIDATE = 2,
592
  PRISKY_CANDIDATE = 3, IRISKY = 4, TRAP_RISKY = 5
593
};
594
 
595
#define WORST_CLASS(class1, class2) \
596
((class1 > class2) ? class1 : class2)
597
 
598
#ifndef __GNUC__
599
#define __inline
600
#endif
601
 
602
#ifndef HAIFA_INLINE
603
#define HAIFA_INLINE __inline
604
#endif
605
 
606
/* Functions in sched-vis.c.  */
607
extern void print_insn (char *, rtx, int);
608
 
609
/* Functions in sched-deps.c.  */
610
extern bool sched_insns_conditions_mutex_p (rtx, rtx);
611
extern void add_dependence (rtx, rtx, enum reg_note);
612
extern void sched_analyze (struct deps *, rtx, rtx);
613
extern void init_deps (struct deps *);
614
extern void free_deps (struct deps *);
615
extern void init_deps_global (void);
616
extern void finish_deps_global (void);
617
extern void add_forw_dep (rtx, rtx);
618
extern void compute_forward_dependences (rtx, rtx);
619
extern rtx find_insn_list (rtx, rtx);
620
extern void init_dependency_caches (int);
621
extern void free_dependency_caches (void);
622
extern void extend_dependency_caches (int, bool);
623
extern enum DEPS_ADJUST_RESULT add_or_update_back_dep (rtx, rtx,
624
                                                       enum reg_note, ds_t);
625
extern void add_or_update_back_forw_dep (rtx, rtx, enum reg_note, ds_t);
626
extern void add_back_forw_dep (rtx, rtx, enum reg_note, ds_t);
627
extern void delete_back_forw_dep (rtx, rtx);
628
extern dw_t get_dep_weak (ds_t, ds_t);
629
extern ds_t set_dep_weak (ds_t, ds_t, dw_t);
630
extern ds_t ds_merge (ds_t, ds_t);
631
 
632
/* Functions in haifa-sched.c.  */
633
extern int haifa_classify_insn (rtx);
634
extern void get_ebb_head_tail (basic_block, basic_block, rtx *, rtx *);
635
extern int no_real_insns_p (rtx, rtx);
636
 
637
extern void rm_line_notes (rtx, rtx);
638
extern void save_line_notes (int, rtx, rtx);
639
extern void restore_line_notes (rtx, rtx);
640
extern void rm_redundant_line_notes (void);
641
extern void rm_other_notes (rtx, rtx);
642
 
643
extern int insn_cost (rtx, rtx, rtx);
644
extern int set_priorities (rtx, rtx);
645
 
646
extern void schedule_block (basic_block *, int);
647
extern void sched_init (void);
648
extern void sched_finish (void);
649
 
650
extern int try_ready (rtx);
651
extern void * xrecalloc (void *, size_t, size_t, size_t);
652
extern void unlink_bb_notes (basic_block, basic_block);
653
extern void add_block (basic_block, basic_block);
654
extern void attach_life_info (void);
655
extern rtx bb_note (basic_block);
656
 
657
#ifdef ENABLE_CHECKING
658
extern void check_reg_live (bool);
659
#endif
660
 
661
#endif /* GCC_SCHED_INT_H */

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