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[/] [openrisc/] [trunk/] [gnu-stable/] [gcc-4.5.1/] [gcc/] [loop-init.c] - Blame information for rev 833

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1 280 jeremybenn
/* Loop optimizer initialization routines and RTL loop optimization passes.
2
   Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008
3
   Free Software Foundation, Inc.
4
 
5
This file is part of GCC.
6
 
7
GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
9
Software Foundation; either version 3, or (at your option) any later
10
version.
11
 
12
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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for more details.
16
 
17
You should have received a copy of the GNU General Public License
18
along with GCC; see the file COPYING3.  If not see
19
<http://www.gnu.org/licenses/>.  */
20
 
21
#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tm.h"
25
#include "rtl.h"
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#include "hard-reg-set.h"
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#include "obstack.h"
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#include "basic-block.h"
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#include "cfgloop.h"
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#include "cfglayout.h"
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#include "tree-pass.h"
32
#include "timevar.h"
33
#include "flags.h"
34
#include "df.h"
35
#include "ggc.h"
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37
 
38
/* Initialize loop structures.  This is used by the tree and RTL loop
39
   optimizers.  FLAGS specify what properties to compute and/or ensure for
40
   loops.  */
41
 
42
void
43
loop_optimizer_init (unsigned flags)
44
{
45
  struct loops *loops;
46
 
47
  gcc_assert (!current_loops);
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  loops = GGC_CNEW (struct loops);
49
 
50
  /* Find the loops.  */
51
 
52
  flow_loops_find (loops);
53
  current_loops = loops;
54
 
55
  if (flags & LOOPS_MAY_HAVE_MULTIPLE_LATCHES)
56
    {
57
      /* If the loops may have multiple latches, we cannot canonicalize
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         them further (and most of the loop manipulation functions will
59
         not work).  However, we avoid modifying cfg, which some
60
         passes may want.  */
61
      gcc_assert ((flags & ~(LOOPS_MAY_HAVE_MULTIPLE_LATCHES
62
                             | LOOPS_HAVE_RECORDED_EXITS)) == 0);
63
      loops_state_set (LOOPS_MAY_HAVE_MULTIPLE_LATCHES);
64
    }
65
  else
66
    disambiguate_loops_with_multiple_latches ();
67
 
68
  /* Create pre-headers.  */
69
  if (flags & LOOPS_HAVE_PREHEADERS)
70
    {
71
      int cp_flags = CP_SIMPLE_PREHEADERS;
72
 
73
      if (flags & LOOPS_HAVE_FALLTHRU_PREHEADERS)
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        cp_flags |= CP_FALLTHRU_PREHEADERS;
75
 
76
      create_preheaders (cp_flags);
77
    }
78
 
79
  /* Force all latches to have only single successor.  */
80
  if (flags & LOOPS_HAVE_SIMPLE_LATCHES)
81
    force_single_succ_latches ();
82
 
83
  /* Mark irreducible loops.  */
84
  if (flags & LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)
85
    mark_irreducible_loops ();
86
 
87
  if (flags & LOOPS_HAVE_RECORDED_EXITS)
88
    record_loop_exits ();
89
 
90
  /* Dump loops.  */
91
  flow_loops_dump (dump_file, NULL, 1);
92
 
93
#ifdef ENABLE_CHECKING
94
  verify_dominators (CDI_DOMINATORS);
95
  verify_loop_structure ();
96
#endif
97
}
98
 
99
/* Finalize loop structures.  */
100
 
101
void
102
loop_optimizer_finalize (void)
103
{
104
  loop_iterator li;
105
  struct loop *loop;
106
  basic_block bb;
107
 
108
  gcc_assert (current_loops != NULL);
109
 
110
  FOR_EACH_LOOP (li, loop, 0)
111
    {
112
      free_simple_loop_desc (loop);
113
    }
114
 
115
  /* Clean up.  */
116
  if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
117
    release_recorded_exits ();
118
  flow_loops_free (current_loops);
119
  ggc_free (current_loops);
120
  current_loops = NULL;
121
 
122
  FOR_ALL_BB (bb)
123
    {
124
      bb->loop_father = NULL;
125
    }
126
 
127
  /* Checking.  */
128
#ifdef ENABLE_CHECKING
129
  /* FIXME: no point to verify flow info after bundling on ia64.  Use this
130
     hack for achieving this.  */
131
  if (!reload_completed)
132
    verify_flow_info ();
133
#endif
134
}
135
 
136
 
137
/* Gate for the RTL loop superpass.  The actual passes are subpasses.
138
   See passes.c for more on that.  */
139
 
140
static bool
141
gate_handle_loop2 (void)
142
{
143
  return (optimize > 0
144
          && (flag_move_loop_invariants
145
              || flag_unswitch_loops
146
              || flag_peel_loops
147
              || flag_unroll_loops
148
#ifdef HAVE_doloop_end
149
              || (flag_branch_on_count_reg && HAVE_doloop_end)
150
#endif
151
              ));
152
}
153
 
154
struct rtl_opt_pass pass_loop2 =
155
{
156
 {
157
  RTL_PASS,
158
  "loop2",                              /* name */
159
  gate_handle_loop2,                    /* gate */
160
  NULL,                                 /* execute */
161
  NULL,                                 /* sub */
162
  NULL,                                 /* next */
163
  0,                                    /* static_pass_number */
164
  TV_LOOP,                              /* tv_id */
165
  0,                                    /* properties_required */
166
  0,                                    /* properties_provided */
167
  0,                                    /* properties_destroyed */
168
  0,                                    /* todo_flags_start */
169
  TODO_dump_func |
170
  TODO_ggc_collect                      /* todo_flags_finish */
171
 }
172
};
173
 
174
 
175
/* Initialization of the RTL loop passes.  */
176
static unsigned int
177
rtl_loop_init (void)
178
{
179
  gcc_assert (current_ir_type () == IR_RTL_CFGLAYOUT);
180
 
181
  if (dump_file)
182
    dump_flow_info (dump_file, dump_flags);
183
 
184
  loop_optimizer_init (LOOPS_NORMAL);
185
  return 0;
186
}
187
 
188
struct rtl_opt_pass pass_rtl_loop_init =
189
{
190
 {
191
  RTL_PASS,
192
  "loop2_init",                           /* name */
193
  NULL,                                 /* gate */
194
  rtl_loop_init,                        /* execute */
195
  NULL,                                 /* sub */
196
  NULL,                                 /* next */
197
  0,                                    /* static_pass_number */
198
  TV_LOOP,                              /* tv_id */
199
  0,                                    /* properties_required */
200
  0,                                    /* properties_provided */
201
  0,                                    /* properties_destroyed */
202
  0,                                    /* todo_flags_start */
203
  TODO_dump_func | TODO_verify_rtl_sharing /* todo_flags_finish */
204
 }
205
};
206
 
207
 
208
/* Finalization of the RTL loop passes.  */
209
 
210
static unsigned int
211
rtl_loop_done (void)
212
{
213
  loop_optimizer_finalize ();
214
  free_dominance_info (CDI_DOMINATORS);
215
 
216
  cleanup_cfg (0);
217
  if (dump_file)
218
    dump_flow_info (dump_file, dump_flags);
219
 
220
  return 0;
221
}
222
 
223
struct rtl_opt_pass pass_rtl_loop_done =
224
{
225
 {
226
  RTL_PASS,
227
  "loop2_done",                          /* name */
228
  NULL,                                 /* gate */
229
  rtl_loop_done,                        /* execute */
230
  NULL,                                 /* sub */
231
  NULL,                                 /* next */
232
  0,                                    /* static_pass_number */
233
  TV_LOOP,                              /* tv_id */
234
  0,                                    /* properties_required */
235
  0,                                    /* properties_provided */
236
  0,                                    /* properties_destroyed */
237
  0,                                    /* todo_flags_start */
238
  TODO_dump_func | TODO_verify_rtl_sharing /* todo_flags_finish */
239
 }
240
};
241
 
242
 
243
/* Loop invariant code motion.  */
244
static bool
245
gate_rtl_move_loop_invariants (void)
246
{
247
  return flag_move_loop_invariants;
248
}
249
 
250
static unsigned int
251
rtl_move_loop_invariants (void)
252
{
253
  if (number_of_loops () > 1)
254
    move_loop_invariants ();
255
  return 0;
256
}
257
 
258
struct rtl_opt_pass pass_rtl_move_loop_invariants =
259
{
260
 {
261
  RTL_PASS,
262
  "loop2_invariant",                    /* name */
263
  gate_rtl_move_loop_invariants,        /* gate */
264
  rtl_move_loop_invariants,             /* execute */
265
  NULL,                                 /* sub */
266
  NULL,                                 /* next */
267
  0,                                    /* static_pass_number */
268
  TV_LOOP_MOVE_INVARIANTS,              /* tv_id */
269
  0,                                    /* properties_required */
270
  0,                                    /* properties_provided */
271
  0,                                    /* properties_destroyed */
272
  0,                                    /* todo_flags_start */
273
  TODO_df_verify |
274
  TODO_df_finish | TODO_verify_rtl_sharing |
275
  TODO_dump_func                        /* todo_flags_finish */
276
 }
277
};
278
 
279
 
280
/* Loop unswitching for RTL.  */
281
static bool
282
gate_rtl_unswitch (void)
283
{
284
  return flag_unswitch_loops;
285
}
286
 
287
static unsigned int
288
rtl_unswitch (void)
289
{
290
  if (number_of_loops () > 1)
291
    unswitch_loops ();
292
  return 0;
293
}
294
 
295
struct rtl_opt_pass pass_rtl_unswitch =
296
{
297
 {
298
  RTL_PASS,
299
  "loop2_unswitch",                      /* name */
300
  gate_rtl_unswitch,                    /* gate */
301
  rtl_unswitch,                         /* execute */
302
  NULL,                                 /* sub */
303
  NULL,                                 /* next */
304
  0,                                    /* static_pass_number */
305
  TV_LOOP_UNSWITCH,                     /* tv_id */
306
  0,                                    /* properties_required */
307
  0,                                    /* properties_provided */
308
  0,                                    /* properties_destroyed */
309
  0,                                    /* todo_flags_start */
310
  TODO_dump_func | TODO_verify_rtl_sharing, /* todo_flags_finish */
311
 }
312
};
313
 
314
 
315
/* Loop unswitching for RTL.  */
316
static bool
317
gate_rtl_unroll_and_peel_loops (void)
318
{
319
  return (flag_peel_loops || flag_unroll_loops || flag_unroll_all_loops);
320
}
321
 
322
static unsigned int
323
rtl_unroll_and_peel_loops (void)
324
{
325
  if (number_of_loops () > 1)
326
    {
327
      int flags = 0;
328
      if (dump_file)
329
        df_dump (dump_file);
330
 
331
      if (flag_peel_loops)
332
        flags |= UAP_PEEL;
333
      if (flag_unroll_loops)
334
        flags |= UAP_UNROLL;
335
      if (flag_unroll_all_loops)
336
        flags |= UAP_UNROLL_ALL;
337
 
338
      unroll_and_peel_loops (flags);
339
    }
340
  return 0;
341
}
342
 
343
struct rtl_opt_pass pass_rtl_unroll_and_peel_loops =
344
{
345
 {
346
  RTL_PASS,
347
  "loop2_unroll",                        /* name */
348
  gate_rtl_unroll_and_peel_loops,       /* gate */
349
  rtl_unroll_and_peel_loops,            /* execute */
350
  NULL,                                 /* sub */
351
  NULL,                                 /* next */
352
  0,                                    /* static_pass_number */
353
  TV_LOOP_UNROLL,                       /* tv_id */
354
  0,                                    /* properties_required */
355
  0,                                    /* properties_provided */
356
  0,                                    /* properties_destroyed */
357
  0,                                    /* todo_flags_start */
358
  TODO_dump_func | TODO_verify_rtl_sharing, /* todo_flags_finish */
359
 }
360
};
361
 
362
 
363
/* The doloop optimization.  */
364
static bool
365
gate_rtl_doloop (void)
366
{
367
#ifdef HAVE_doloop_end
368
  return (flag_branch_on_count_reg && HAVE_doloop_end);
369
#else
370
  return 0;
371
#endif
372
}
373
 
374
static unsigned int
375
rtl_doloop (void)
376
{
377
#ifdef HAVE_doloop_end
378
  if (number_of_loops () > 1)
379
    doloop_optimize_loops ();
380
#endif
381
  return 0;
382
}
383
 
384
struct rtl_opt_pass pass_rtl_doloop =
385
{
386
 {
387
  RTL_PASS,
388
  "loop2_doloop",                        /* name */
389
  gate_rtl_doloop,                      /* gate */
390
  rtl_doloop,                           /* execute */
391
  NULL,                                 /* sub */
392
  NULL,                                 /* next */
393
  0,                                    /* static_pass_number */
394
  TV_LOOP_DOLOOP,                       /* tv_id */
395
  0,                                    /* properties_required */
396
  0,                                    /* properties_provided */
397
  0,                                    /* properties_destroyed */
398
  0,                                    /* todo_flags_start */
399
  TODO_dump_func | TODO_verify_rtl_sharing /* todo_flags_finish */
400
 }
401
};
402
 

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