summaryrefslogtreecommitdiff
path: root/gcc/tree-ssa-math-opts.c
blob: 49fd1707d1e6a4355b2ebc2d7cad9a12d5bbd334 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
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
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
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
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
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
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
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
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
699
700
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
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
/* Global, SSA-based optimizations using mathematical identities.
   Copyright (C) 2005, 2006, 2007 Free Software Foundation, Inc.
   
This file is part of GCC.
   
GCC is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3, or (at your option) any
later version.
   
GCC is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.
   
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

/* Currently, the only mini-pass in this file tries to CSE reciprocal
   operations.  These are common in sequences such as this one:

	modulus = sqrt(x*x + y*y + z*z);
	x = x / modulus;
	y = y / modulus;
	z = z / modulus;

   that can be optimized to

	modulus = sqrt(x*x + y*y + z*z);
        rmodulus = 1.0 / modulus;
	x = x * rmodulus;
	y = y * rmodulus;
	z = z * rmodulus;

   We do this for loop invariant divisors, and with this pass whenever
   we notice that a division has the same divisor multiple times.

   Of course, like in PRE, we don't insert a division if a dominator
   already has one.  However, this cannot be done as an extension of
   PRE for several reasons.

   First of all, with some experiments it was found out that the
   transformation is not always useful if there are only two divisions
   hy the same divisor.  This is probably because modern processors
   can pipeline the divisions; on older, in-order processors it should
   still be effective to optimize two divisions by the same number.
   We make this a param, and it shall be called N in the remainder of
   this comment.

   Second, if trapping math is active, we have less freedom on where
   to insert divisions: we can only do so in basic blocks that already
   contain one.  (If divisions don't trap, instead, we can insert
   divisions elsewhere, which will be in blocks that are common dominators
   of those that have the division).

   We really don't want to compute the reciprocal unless a division will
   be found.  To do this, we won't insert the division in a basic block
   that has less than N divisions *post-dominating* it.

   The algorithm constructs a subset of the dominator tree, holding the
   blocks containing the divisions and the common dominators to them,
   and walk it twice.  The first walk is in post-order, and it annotates
   each block with the number of divisions that post-dominate it: this
   gives information on where divisions can be inserted profitably.
   The second walk is in pre-order, and it inserts divisions as explained
   above, and replaces divisions by multiplications.

   In the best case, the cost of the pass is O(n_statements).  In the
   worst-case, the cost is due to creating the dominator tree subset,
   with a cost of O(n_basic_blocks ^ 2); however this can only happen
   for n_statements / n_basic_blocks statements.  So, the amortized cost
   of creating the dominator tree subset is O(n_basic_blocks) and the
   worst-case cost of the pass is O(n_statements * n_basic_blocks).

   More practically, the cost will be small because there are few
   divisions, and they tend to be in the same basic block, so insert_bb
   is called very few times.

   If we did this using domwalk.c, an efficient implementation would have
   to work on all the variables in a single pass, because we could not
   work on just a subset of the dominator tree, as we do now, and the
   cost would also be something like O(n_statements * n_basic_blocks).
   The data structures would be more complex in order to work on all the
   variables in a single pass.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "flags.h"
#include "tree.h"
#include "tree-flow.h"
#include "real.h"
#include "timevar.h"
#include "tree-pass.h"
#include "alloc-pool.h"
#include "basic-block.h"
#include "target.h"


/* This structure represents one basic block that either computes a
   division, or is a common dominator for basic block that compute a
   division.  */
struct occurrence {
  /* The basic block represented by this structure.  */
  basic_block bb;

  /* If non-NULL, the SSA_NAME holding the definition for a reciprocal
     inserted in BB.  */
  tree recip_def;

  /* If non-NULL, the GIMPLE_MODIFY_STMT for a reciprocal computation that
     was inserted in BB.  */
  tree recip_def_stmt;

  /* Pointer to a list of "struct occurrence"s for blocks dominated
     by BB.  */
  struct occurrence *children;

  /* Pointer to the next "struct occurrence"s in the list of blocks
     sharing a common dominator.  */
  struct occurrence *next;

  /* The number of divisions that are in BB before compute_merit.  The
     number of divisions that are in BB or post-dominate it after
     compute_merit.  */
  int num_divisions;

  /* True if the basic block has a division, false if it is a common
     dominator for basic blocks that do.  If it is false and trapping
     math is active, BB is not a candidate for inserting a reciprocal.  */
  bool bb_has_division;
};


/* The instance of "struct occurrence" representing the highest
   interesting block in the dominator tree.  */
static struct occurrence *occ_head;

/* Allocation pool for getting instances of "struct occurrence".  */
static alloc_pool occ_pool;



/* Allocate and return a new struct occurrence for basic block BB, and
   whose children list is headed by CHILDREN.  */
static struct occurrence *
occ_new (basic_block bb, struct occurrence *children)
{
  struct occurrence *occ;

  bb->aux = occ = (struct occurrence *) pool_alloc (occ_pool);
  memset (occ, 0, sizeof (struct occurrence));

  occ->bb = bb;
  occ->children = children;
  return occ;
}


/* Insert NEW_OCC into our subset of the dominator tree.  P_HEAD points to a
   list of "struct occurrence"s, one per basic block, having IDOM as
   their common dominator.

   We try to insert NEW_OCC as deep as possible in the tree, and we also
   insert any other block that is a common dominator for BB and one
   block already in the tree.  */

static void
insert_bb (struct occurrence *new_occ, basic_block idom,
	   struct occurrence **p_head)
{
  struct occurrence *occ, **p_occ;

  for (p_occ = p_head; (occ = *p_occ) != NULL; )
    {
      basic_block bb = new_occ->bb, occ_bb = occ->bb;
      basic_block dom = nearest_common_dominator (CDI_DOMINATORS, occ_bb, bb);
      if (dom == bb)
	{
	  /* BB dominates OCC_BB.  OCC becomes NEW_OCC's child: remove OCC
	     from its list.  */
	  *p_occ = occ->next;
	  occ->next = new_occ->children;
	  new_occ->children = occ;

	  /* Try the next block (it may as well be dominated by BB).  */
	}

      else if (dom == occ_bb)
	{
	  /* OCC_BB dominates BB.  Tail recurse to look deeper.  */
	  insert_bb (new_occ, dom, &occ->children);
	  return;
	}

      else if (dom != idom)
	{
	  gcc_assert (!dom->aux);

	  /* There is a dominator between IDOM and BB, add it and make
	     two children out of NEW_OCC and OCC.  First, remove OCC from
	     its list.	*/
	  *p_occ = occ->next;
	  new_occ->next = occ;
	  occ->next = NULL;

	  /* None of the previous blocks has DOM as a dominator: if we tail
	     recursed, we would reexamine them uselessly. Just switch BB with
	     DOM, and go on looking for blocks dominated by DOM.  */
          new_occ = occ_new (dom, new_occ);
	}

      else
	{
	  /* Nothing special, go on with the next element.  */
	  p_occ = &occ->next;
	}
    }

  /* No place was found as a child of IDOM.  Make BB a sibling of IDOM.  */
  new_occ->next = *p_head;
  *p_head = new_occ;
}

/* Register that we found a division in BB.  */

static inline void
register_division_in (basic_block bb)
{
  struct occurrence *occ;

  occ = (struct occurrence *) bb->aux;
  if (!occ)
    {
      occ = occ_new (bb, NULL);
      insert_bb (occ, ENTRY_BLOCK_PTR, &occ_head);
    }

  occ->bb_has_division = true;
  occ->num_divisions++;
}


/* Compute the number of divisions that postdominate each block in OCC and
   its children.  */

static void
compute_merit (struct occurrence *occ)
{
  struct occurrence *occ_child;
  basic_block dom = occ->bb;

  for (occ_child = occ->children; occ_child; occ_child = occ_child->next)
    {
      basic_block bb;
      if (occ_child->children)
        compute_merit (occ_child);

      if (flag_exceptions)
	bb = single_noncomplex_succ (dom);
      else
	bb = dom;

      if (dominated_by_p (CDI_POST_DOMINATORS, bb, occ_child->bb))
        occ->num_divisions += occ_child->num_divisions;
    }
}


/* Return whether USE_STMT is a floating-point division by DEF.  */
static inline bool
is_division_by (tree use_stmt, tree def)
{
  return TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
	 && TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == RDIV_EXPR
	 && TREE_OPERAND (GIMPLE_STMT_OPERAND (use_stmt, 1), 1) == def
	 /* Do not recognize x / x as valid division, as we are getting
	    confused later by replacing all immediate uses x in such
	    a stmt.  */
	 && TREE_OPERAND (GIMPLE_STMT_OPERAND (use_stmt, 1), 0) != def;
}

/* Walk the subset of the dominator tree rooted at OCC, setting the
   RECIP_DEF field to a definition of 1.0 / DEF that can be used in
   the given basic block.  The field may be left NULL, of course,
   if it is not possible or profitable to do the optimization.

   DEF_BSI is an iterator pointing at the statement defining DEF.
   If RECIP_DEF is set, a dominator already has a computation that can
   be used.  */

static void
insert_reciprocals (block_stmt_iterator *def_bsi, struct occurrence *occ,
		    tree def, tree recip_def, int threshold)
{
  tree type, new_stmt;
  block_stmt_iterator bsi;
  struct occurrence *occ_child;

  if (!recip_def
      && (occ->bb_has_division || !flag_trapping_math)
      && occ->num_divisions >= threshold)
    {
      /* Make a variable with the replacement and substitute it.  */
      type = TREE_TYPE (def);
      recip_def = make_rename_temp (type, "reciptmp");
      new_stmt = build_gimple_modify_stmt (recip_def,
					   fold_build2 (RDIV_EXPR, type,
							build_one_cst (type),
							def));
  
  
      if (occ->bb_has_division)
        {
          /* Case 1: insert before an existing division.  */
          bsi = bsi_after_labels (occ->bb);
          while (!bsi_end_p (bsi) && !is_division_by (bsi_stmt (bsi), def))
	    bsi_next (&bsi);

          bsi_insert_before (&bsi, new_stmt, BSI_SAME_STMT);
        }
      else if (def_bsi && occ->bb == def_bsi->bb)
        {
          /* Case 2: insert right after the definition.  Note that this will
	     never happen if the definition statement can throw, because in
	     that case the sole successor of the statement's basic block will
	     dominate all the uses as well.  */
          bsi_insert_after (def_bsi, new_stmt, BSI_NEW_STMT);
        }
      else
        {
          /* Case 3: insert in a basic block not containing defs/uses.  */
          bsi = bsi_after_labels (occ->bb);
          bsi_insert_before (&bsi, new_stmt, BSI_SAME_STMT);
        }

      occ->recip_def_stmt = new_stmt;
    }

  occ->recip_def = recip_def;
  for (occ_child = occ->children; occ_child; occ_child = occ_child->next)
    insert_reciprocals (def_bsi, occ_child, def, recip_def, threshold);
}


/* Replace the division at USE_P with a multiplication by the reciprocal, if
   possible.  */

static inline void
replace_reciprocal (use_operand_p use_p)
{
  tree use_stmt = USE_STMT (use_p);
  basic_block bb = bb_for_stmt (use_stmt);
  struct occurrence *occ = (struct occurrence *) bb->aux;

  if (occ->recip_def && use_stmt != occ->recip_def_stmt)
    {
      TREE_SET_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1), MULT_EXPR);
      SET_USE (use_p, occ->recip_def);
      fold_stmt_inplace (use_stmt);
      update_stmt (use_stmt);
    }
}


/* Free OCC and return one more "struct occurrence" to be freed.  */

static struct occurrence *
free_bb (struct occurrence *occ)
{
  struct occurrence *child, *next;

  /* First get the two pointers hanging off OCC.  */
  next = occ->next;
  child = occ->children;
  occ->bb->aux = NULL;
  pool_free (occ_pool, occ);

  /* Now ensure that we don't recurse unless it is necessary.  */
  if (!child)
    return next;
  else
    {
      while (next)
	next = free_bb (next);

      return child;
    }
}


/* Look for floating-point divisions among DEF's uses, and try to
   replace them by multiplications with the reciprocal.  Add
   as many statements computing the reciprocal as needed.

   DEF must be a GIMPLE register of a floating-point type.  */

static void
execute_cse_reciprocals_1 (block_stmt_iterator *def_bsi, tree def)
{
  use_operand_p use_p;
  imm_use_iterator use_iter;
  struct occurrence *occ;
  int count = 0, threshold;

  gcc_assert (FLOAT_TYPE_P (TREE_TYPE (def)) && is_gimple_reg (def));

  FOR_EACH_IMM_USE_FAST (use_p, use_iter, def)
    {
      tree use_stmt = USE_STMT (use_p);
      if (is_division_by (use_stmt, def))
	{
	  register_division_in (bb_for_stmt (use_stmt));
	  count++;
	}
    }
  
  /* Do the expensive part only if we can hope to optimize something.  */
  threshold = targetm.min_divisions_for_recip_mul (TYPE_MODE (TREE_TYPE (def)));
  if (count >= threshold)
    {
      tree use_stmt;
      for (occ = occ_head; occ; occ = occ->next)
	{
	  compute_merit (occ);
	  insert_reciprocals (def_bsi, occ, def, NULL, threshold);
	}

      FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, def)
	{
	  if (is_division_by (use_stmt, def))
	    {
	      FOR_EACH_IMM_USE_ON_STMT (use_p, use_iter)
		replace_reciprocal (use_p);
	    }
	}
    }

  for (occ = occ_head; occ; )
    occ = free_bb (occ);

  occ_head = NULL;
}

static bool
gate_cse_reciprocals (void)
{
  return optimize && !optimize_size && flag_reciprocal_math;
}

/* Go through all the floating-point SSA_NAMEs, and call
   execute_cse_reciprocals_1 on each of them.  */
static unsigned int
execute_cse_reciprocals (void)
{
  basic_block bb;
  tree arg;

  occ_pool = create_alloc_pool ("dominators for recip",
				sizeof (struct occurrence),
				n_basic_blocks / 3 + 1);

  calculate_dominance_info (CDI_DOMINATORS);
  calculate_dominance_info (CDI_POST_DOMINATORS);

#ifdef ENABLE_CHECKING
  FOR_EACH_BB (bb)
    gcc_assert (!bb->aux);
#endif

  for (arg = DECL_ARGUMENTS (cfun->decl); arg; arg = TREE_CHAIN (arg))
    if (gimple_default_def (cfun, arg)
	&& FLOAT_TYPE_P (TREE_TYPE (arg))
	&& is_gimple_reg (arg))
      execute_cse_reciprocals_1 (NULL, gimple_default_def (cfun, arg));

  FOR_EACH_BB (bb)
    {
      block_stmt_iterator bsi;
      tree phi, def;

      for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
	{
	  def = PHI_RESULT (phi);
	  if (FLOAT_TYPE_P (TREE_TYPE (def))
	      && is_gimple_reg (def))
	    execute_cse_reciprocals_1 (NULL, def);
	}

      for (bsi = bsi_after_labels (bb); !bsi_end_p (bsi); bsi_next (&bsi))
        {
	  tree stmt = bsi_stmt (bsi);

	  if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
	      && (def = SINGLE_SSA_TREE_OPERAND (stmt, SSA_OP_DEF)) != NULL
	      && FLOAT_TYPE_P (TREE_TYPE (def))
	      && TREE_CODE (def) == SSA_NAME)
	    execute_cse_reciprocals_1 (&bsi, def);
	}

      /* Scan for a/func(b) and convert it to reciprocal a*rfunc(b).  */
      for (bsi = bsi_after_labels (bb); !bsi_end_p (bsi); bsi_next (&bsi))
        {
	  tree stmt = bsi_stmt (bsi);
	  tree fndecl;

	  if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
	      && TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == RDIV_EXPR)
	    {
	      tree arg1 = TREE_OPERAND (GIMPLE_STMT_OPERAND (stmt, 1), 1);
	      tree stmt1;

	      if (TREE_CODE (arg1) != SSA_NAME)
		continue;

	      stmt1 = SSA_NAME_DEF_STMT (arg1);

	      if (TREE_CODE (stmt1) == GIMPLE_MODIFY_STMT
		  && TREE_CODE (GIMPLE_STMT_OPERAND (stmt1, 1)) == CALL_EXPR
		  && (fndecl
		      = get_callee_fndecl (GIMPLE_STMT_OPERAND (stmt1, 1)))
		  && (DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL
		      || DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_MD))
		{
		  enum built_in_function code;
		  bool md_code;
		  tree arg10;
		  tree tmp;

		  code = DECL_FUNCTION_CODE (fndecl);
		  md_code = DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_MD;

		  fndecl = targetm.builtin_reciprocal (code, md_code, false);
		  if (!fndecl)
		    continue;

		  arg10 = CALL_EXPR_ARG (GIMPLE_STMT_OPERAND (stmt1, 1), 0);
		  tmp = build_call_expr (fndecl, 1, arg10);
		  GIMPLE_STMT_OPERAND (stmt1, 1) = tmp;
		  update_stmt (stmt1);

		  TREE_SET_CODE (GIMPLE_STMT_OPERAND (stmt, 1), MULT_EXPR);
		  fold_stmt_inplace (stmt);
		  update_stmt (stmt);
		}
	    }
	}
    }

  free_dominance_info (CDI_DOMINATORS);
  free_dominance_info (CDI_POST_DOMINATORS);
  free_alloc_pool (occ_pool);
  return 0;
}

struct gimple_opt_pass pass_cse_reciprocals =
{
 {
  GIMPLE_PASS,
  "recip",				/* name */
  gate_cse_reciprocals,			/* gate */
  execute_cse_reciprocals,		/* execute */
  NULL,					/* sub */
  NULL,					/* next */
  0,					/* static_pass_number */
  0,					/* tv_id */
  PROP_ssa,				/* properties_required */
  0,					/* properties_provided */
  0,					/* properties_destroyed */
  0,					/* todo_flags_start */
  TODO_dump_func | TODO_update_ssa | TODO_verify_ssa
    | TODO_verify_stmts                /* todo_flags_finish */
 }
};

/* Records an occurrence at statement USE_STMT in the vector of trees
   STMTS if it is dominated by *TOP_BB or dominates it or this basic block
   is not yet initialized.  Returns true if the occurrence was pushed on
   the vector.  Adjusts *TOP_BB to be the basic block dominating all
   statements in the vector.  */

static bool
maybe_record_sincos (VEC(tree, heap) **stmts,
		     basic_block *top_bb, tree use_stmt)
{
  basic_block use_bb = bb_for_stmt (use_stmt);
  if (*top_bb
      && (*top_bb == use_bb
	  || dominated_by_p (CDI_DOMINATORS, use_bb, *top_bb)))
    VEC_safe_push (tree, heap, *stmts, use_stmt);
  else if (!*top_bb
	   || dominated_by_p (CDI_DOMINATORS, *top_bb, use_bb))
    {
      VEC_safe_push (tree, heap, *stmts, use_stmt);
      *top_bb = use_bb;
    }
  else
    return false;

  return true;
}

/* Look for sin, cos and cexpi calls with the same argument NAME and
   create a single call to cexpi CSEing the result in this case.
   We first walk over all immediate uses of the argument collecting
   statements that we can CSE in a vector and in a second pass replace
   the statement rhs with a REALPART or IMAGPART expression on the
   result of the cexpi call we insert before the use statement that
   dominates all other candidates.  */

static void
execute_cse_sincos_1 (tree name)
{
  block_stmt_iterator bsi;
  imm_use_iterator use_iter;
  tree def_stmt, use_stmt, fndecl, res, call, stmt, type;
  int seen_cos = 0, seen_sin = 0, seen_cexpi = 0;
  VEC(tree, heap) *stmts = NULL;
  basic_block top_bb = NULL;
  int i;

  type = TREE_TYPE (name);
  FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, name)
    {
      if (TREE_CODE (use_stmt) != GIMPLE_MODIFY_STMT
	  || TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) != CALL_EXPR
	  || !(fndecl = get_callee_fndecl (GIMPLE_STMT_OPERAND (use_stmt, 1)))
	  || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL)
	continue;

      switch (DECL_FUNCTION_CODE (fndecl))
	{
	CASE_FLT_FN (BUILT_IN_COS):
	  seen_cos |= maybe_record_sincos (&stmts, &top_bb, use_stmt) ? 1 : 0;
	  break;

	CASE_FLT_FN (BUILT_IN_SIN):
	  seen_sin |= maybe_record_sincos (&stmts, &top_bb, use_stmt) ? 1 : 0;
	  break;

	CASE_FLT_FN (BUILT_IN_CEXPI):
	  seen_cexpi |= maybe_record_sincos (&stmts, &top_bb, use_stmt) ? 1 : 0;
	  break;

	default:;
	}
    }

  if (seen_cos + seen_sin + seen_cexpi <= 1)
    {
      VEC_free(tree, heap, stmts);
      return;
    }

  /* Simply insert cexpi at the beginning of top_bb but not earlier than
     the name def statement.  */
  fndecl = mathfn_built_in (type, BUILT_IN_CEXPI);
  if (!fndecl)
    return;
  res = make_rename_temp (TREE_TYPE (TREE_TYPE (fndecl)), "sincostmp");
  call = build_call_expr (fndecl, 1, name);
  stmt = build_gimple_modify_stmt (res, call);
  def_stmt = SSA_NAME_DEF_STMT (name);
  if (!SSA_NAME_IS_DEFAULT_DEF (name)
      && TREE_CODE (def_stmt) != PHI_NODE
      && bb_for_stmt (def_stmt) == top_bb)
    {
      bsi = bsi_for_stmt (def_stmt);
      bsi_insert_after (&bsi, stmt, BSI_SAME_STMT);
    }
  else
    {
      bsi = bsi_after_labels (top_bb);
      bsi_insert_before (&bsi, stmt, BSI_SAME_STMT);
    }
  update_stmt (stmt);

  /* And adjust the recorded old call sites.  */
  for (i = 0; VEC_iterate(tree, stmts, i, use_stmt); ++i)
    {
      fndecl = get_callee_fndecl (GIMPLE_STMT_OPERAND (use_stmt, 1));
      switch (DECL_FUNCTION_CODE (fndecl))
	{
	CASE_FLT_FN (BUILT_IN_COS):
	  GIMPLE_STMT_OPERAND (use_stmt, 1) = fold_build1 (REALPART_EXPR,
							   type, res);
	  break;

	CASE_FLT_FN (BUILT_IN_SIN):
	  GIMPLE_STMT_OPERAND (use_stmt, 1) = fold_build1 (IMAGPART_EXPR,
							   type, res);
	  break;

	CASE_FLT_FN (BUILT_IN_CEXPI):
	  GIMPLE_STMT_OPERAND (use_stmt, 1) = res;
	  break;

	default:;
	  gcc_unreachable ();
	}

	update_stmt (use_stmt);
    }

  VEC_free(tree, heap, stmts);
}

/* Go through all calls to sin, cos and cexpi and call execute_cse_sincos_1
   on the SSA_NAME argument of each of them.  */

static unsigned int
execute_cse_sincos (void)
{
  basic_block bb;

  calculate_dominance_info (CDI_DOMINATORS);

  FOR_EACH_BB (bb)
    {
      block_stmt_iterator bsi;

      for (bsi = bsi_after_labels (bb); !bsi_end_p (bsi); bsi_next (&bsi))
        {
	  tree stmt = bsi_stmt (bsi);
	  tree fndecl;

	  if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
	      && TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == CALL_EXPR
	      && (fndecl = get_callee_fndecl (GIMPLE_STMT_OPERAND (stmt, 1)))
	      && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
	    {
	      tree arg;

	      switch (DECL_FUNCTION_CODE (fndecl))
		{
		CASE_FLT_FN (BUILT_IN_COS):
		CASE_FLT_FN (BUILT_IN_SIN):
		CASE_FLT_FN (BUILT_IN_CEXPI):
		  arg = GIMPLE_STMT_OPERAND (stmt, 1);
		  arg = CALL_EXPR_ARG (arg, 0);
		  if (TREE_CODE (arg) == SSA_NAME)
		    execute_cse_sincos_1 (arg);
		  break;

		default:;
		}
	    }
	}
    }

  free_dominance_info (CDI_DOMINATORS);
  return 0;
}

static bool
gate_cse_sincos (void)
{
  /* Make sure we have either sincos or cexp.  */
  return (TARGET_HAS_SINCOS
	  || TARGET_C99_FUNCTIONS)
	 && optimize;
}

struct gimple_opt_pass pass_cse_sincos =
{
 {
  GIMPLE_PASS,
  "sincos",				/* name */
  gate_cse_sincos,			/* gate */
  execute_cse_sincos,			/* execute */
  NULL,					/* sub */
  NULL,					/* next */
  0,					/* static_pass_number */
  0,					/* tv_id */
  PROP_ssa,				/* properties_required */
  0,					/* properties_provided */
  0,					/* properties_destroyed */
  0,					/* todo_flags_start */
  TODO_dump_func | TODO_update_ssa | TODO_verify_ssa
    | TODO_verify_stmts                 /* todo_flags_finish */
 }
};

/* Find all expressions in the form of sqrt(a/b) and
   convert them to rsqrt(b/a).  */

static unsigned int
execute_convert_to_rsqrt (void)
{
  basic_block bb;

  FOR_EACH_BB (bb)
    {
      block_stmt_iterator bsi;

      for (bsi = bsi_after_labels (bb); !bsi_end_p (bsi); bsi_next (&bsi))
        {
	  tree stmt = bsi_stmt (bsi);
	  tree fndecl;

	  if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
	      && TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == CALL_EXPR
	      && (fndecl = get_callee_fndecl (GIMPLE_STMT_OPERAND (stmt, 1)))
	      && (DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL
		  || DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_MD))
	    {
	      enum built_in_function code;
	      bool md_code;
	      tree arg1;
	      tree stmt1;

	      code = DECL_FUNCTION_CODE (fndecl);
	      md_code = DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_MD;

	      fndecl = targetm.builtin_reciprocal (code, md_code, true);
	      if (!fndecl)
		continue;

	      arg1 = CALL_EXPR_ARG (GIMPLE_STMT_OPERAND (stmt, 1), 0);

	      if (TREE_CODE (arg1) != SSA_NAME)
		continue;

	      stmt1 = SSA_NAME_DEF_STMT (arg1);

	      if (TREE_CODE (stmt1) == GIMPLE_MODIFY_STMT
		  && TREE_CODE (GIMPLE_STMT_OPERAND (stmt1, 1)) == RDIV_EXPR)
		{
		  tree arg10, arg11;
		  tree tmp;

		  arg10 = TREE_OPERAND (GIMPLE_STMT_OPERAND (stmt1, 1), 0);
		  arg11 = TREE_OPERAND (GIMPLE_STMT_OPERAND (stmt1, 1), 1);

		  /* Swap operands of RDIV_EXPR.  */
		  TREE_OPERAND (GIMPLE_STMT_OPERAND (stmt1, 1), 0) = arg11;
		  TREE_OPERAND (GIMPLE_STMT_OPERAND (stmt1, 1), 1) = arg10;
		  fold_stmt_inplace (stmt1);
		  update_stmt (stmt1);

		  tmp = build_call_expr (fndecl, 1, arg1);
		  GIMPLE_STMT_OPERAND (stmt, 1) = tmp;
		  update_stmt (stmt);
		}
	    }
	}
    }

  return 0;
}

static bool
gate_convert_to_rsqrt (void)
{
  return flag_unsafe_math_optimizations && optimize;
}

struct gimple_opt_pass pass_convert_to_rsqrt =
{
 {
  GIMPLE_PASS,
  "rsqrt",				/* name */
  gate_convert_to_rsqrt,		/* gate */
  execute_convert_to_rsqrt,		/* execute */
  NULL,					/* sub */
  NULL,					/* next */
  0,					/* static_pass_number */
  0,					/* tv_id */
  PROP_ssa,				/* properties_required */
  0,					/* properties_provided */
  0,					/* properties_destroyed */
  0,					/* todo_flags_start */
  TODO_dump_func | TODO_update_ssa | TODO_verify_ssa
    | TODO_verify_stmts                 /* todo_flags_finish */
 }
};