1/* CPU mode switching
2   Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
3   Free Software Foundation, Inc.
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free
9Software Foundation; either version 2, or (at your option) any later
10version.
11
12GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or
14FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15for more details.
16
17You should have received a copy of the GNU General Public License
18along with GCC; see the file COPYING.  If not, write to the Free
19Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
2002110-1301, USA.  */
21
22#include "config.h"
23#include "system.h"
24#include "coretypes.h"
25#include "tm.h"
26#include "rtl.h"
27#include "regs.h"
28#include "hard-reg-set.h"
29#include "flags.h"
30#include "real.h"
31#include "insn-config.h"
32#include "recog.h"
33#include "basic-block.h"
34#include "output.h"
35#include "tm_p.h"
36#include "function.h"
37#include "tree-pass.h"
38#include "timevar.h"
39
40/* We want target macros for the mode switching code to be able to refer
41   to instruction attribute values.  */
42#include "insn-attr.h"
43
44#ifdef OPTIMIZE_MODE_SWITCHING
45
46/* The algorithm for setting the modes consists of scanning the insn list
47   and finding all the insns which require a specific mode.  Each insn gets
48   a unique struct seginfo element.  These structures are inserted into a list
49   for each basic block.  For each entity, there is an array of bb_info over
50   the flow graph basic blocks (local var 'bb_info'), and contains a list
51   of all insns within that basic block, in the order they are encountered.
52
53   For each entity, any basic block WITHOUT any insns requiring a specific
54   mode are given a single entry, without a mode.  (Each basic block
55   in the flow graph must have at least one entry in the segment table.)
56
57   The LCM algorithm is then run over the flow graph to determine where to
58   place the sets to the highest-priority value in respect of first the first
59   insn in any one block.  Any adjustments required to the transparency
60   vectors are made, then the next iteration starts for the next-lower
61   priority mode, till for each entity all modes are exhausted.
62
63   More details are located in the code for optimize_mode_switching().  */
64
65/* This structure contains the information for each insn which requires
66   either single or double mode to be set.
67   MODE is the mode this insn must be executed in.
68   INSN_PTR is the insn to be executed (may be the note that marks the
69   beginning of a basic block).
70   BBNUM is the flow graph basic block this insn occurs in.
71   NEXT is the next insn in the same basic block.  */
72struct seginfo
73{
74  int mode;
75  rtx insn_ptr;
76  int bbnum;
77  struct seginfo *next;
78  HARD_REG_SET regs_live;
79};
80
81struct bb_info
82{
83  struct seginfo *seginfo;
84  int computing;
85};
86
87/* These bitmaps are used for the LCM algorithm.  */
88
89static sbitmap *antic;
90static sbitmap *transp;
91static sbitmap *comp;
92
93static struct seginfo * new_seginfo (int, rtx, int, HARD_REG_SET);
94static void add_seginfo (struct bb_info *, struct seginfo *);
95static void reg_dies (rtx, HARD_REG_SET);
96static void reg_becomes_live (rtx, rtx, void *);
97static void make_preds_opaque (basic_block, int);
98
99
100/* This function will allocate a new BBINFO structure, initialized
101   with the MODE, INSN, and basic block BB parameters.  */
102
103static struct seginfo *
104new_seginfo (int mode, rtx insn, int bb, HARD_REG_SET regs_live)
105{
106  struct seginfo *ptr;
107  ptr = xmalloc (sizeof (struct seginfo));
108  ptr->mode = mode;
109  ptr->insn_ptr = insn;
110  ptr->bbnum = bb;
111  ptr->next = NULL;
112  COPY_HARD_REG_SET (ptr->regs_live, regs_live);
113  return ptr;
114}
115
116/* Add a seginfo element to the end of a list.
117   HEAD is a pointer to the list beginning.
118   INFO is the structure to be linked in.  */
119
120static void
121add_seginfo (struct bb_info *head, struct seginfo *info)
122{
123  struct seginfo *ptr;
124
125  if (head->seginfo == NULL)
126    head->seginfo = info;
127  else
128    {
129      ptr = head->seginfo;
130      while (ptr->next != NULL)
131	ptr = ptr->next;
132      ptr->next = info;
133    }
134}
135
136/* Make all predecessors of basic block B opaque, recursively, till we hit
137   some that are already non-transparent, or an edge where aux is set; that
138   denotes that a mode set is to be done on that edge.
139   J is the bit number in the bitmaps that corresponds to the entity that
140   we are currently handling mode-switching for.  */
141
142static void
143make_preds_opaque (basic_block b, int j)
144{
145  edge e;
146  edge_iterator ei;
147
148  FOR_EACH_EDGE (e, ei, b->preds)
149    {
150      basic_block pb = e->src;
151
152      if (e->aux || ! TEST_BIT (transp[pb->index], j))
153	continue;
154
155      RESET_BIT (transp[pb->index], j);
156      make_preds_opaque (pb, j);
157    }
158}
159
160/* Record in LIVE that register REG died.  */
161
162static void
163reg_dies (rtx reg, HARD_REG_SET live)
164{
165  int regno, nregs;
166
167  if (!REG_P (reg))
168    return;
169
170  regno = REGNO (reg);
171  if (regno < FIRST_PSEUDO_REGISTER)
172    for (nregs = hard_regno_nregs[regno][GET_MODE (reg)] - 1; nregs >= 0;
173	 nregs--)
174      CLEAR_HARD_REG_BIT (live, regno + nregs);
175}
176
177/* Record in LIVE that register REG became live.
178   This is called via note_stores.  */
179
180static void
181reg_becomes_live (rtx reg, rtx setter ATTRIBUTE_UNUSED, void *live)
182{
183  int regno, nregs;
184
185  if (GET_CODE (reg) == SUBREG)
186    reg = SUBREG_REG (reg);
187
188  if (!REG_P (reg))
189    return;
190
191  regno = REGNO (reg);
192  if (regno < FIRST_PSEUDO_REGISTER)
193    for (nregs = hard_regno_nregs[regno][GET_MODE (reg)] - 1; nregs >= 0;
194	 nregs--)
195      SET_HARD_REG_BIT (* (HARD_REG_SET *) live, regno + nregs);
196}
197
198/* Make sure if MODE_ENTRY is defined the MODE_EXIT is defined
199   and vice versa.  */
200#if defined (MODE_ENTRY) != defined (MODE_EXIT)
201 #error "Both MODE_ENTRY and MODE_EXIT must be defined"
202#endif
203
204#if defined (MODE_ENTRY) && defined (MODE_EXIT)
205/* Split the fallthrough edge to the exit block, so that we can note
206   that there NORMAL_MODE is required.  Return the new block if it's
207   inserted before the exit block.  Otherwise return null.  */
208
209static basic_block
210create_pre_exit (int n_entities, int *entity_map, const int *num_modes)
211{
212  edge eg;
213  edge_iterator ei;
214  basic_block pre_exit;
215
216  /* The only non-call predecessor at this stage is a block with a
217     fallthrough edge; there can be at most one, but there could be
218     none at all, e.g. when exit is called.  */
219  pre_exit = 0;
220  FOR_EACH_EDGE (eg, ei, EXIT_BLOCK_PTR->preds)
221    if (eg->flags & EDGE_FALLTHRU)
222      {
223	basic_block src_bb = eg->src;
224	regset live_at_end = src_bb->il.rtl->global_live_at_end;
225	rtx last_insn, ret_reg;
226
227	gcc_assert (!pre_exit);
228	/* If this function returns a value at the end, we have to
229	   insert the final mode switch before the return value copy
230	   to its hard register.  */
231	if (EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 1
232	    && NONJUMP_INSN_P ((last_insn = BB_END (src_bb)))
233	    && GET_CODE (PATTERN (last_insn)) == USE
234	    && GET_CODE ((ret_reg = XEXP (PATTERN (last_insn), 0))) == REG)
235	  {
236	    int ret_start = REGNO (ret_reg);
237	    int nregs = hard_regno_nregs[ret_start][GET_MODE (ret_reg)];
238	    int ret_end = ret_start + nregs;
239	    int short_block = 0;
240	    int maybe_builtin_apply = 0;
241	    int forced_late_switch = 0;
242	    rtx before_return_copy;
243
244	    do
245	      {
246		rtx return_copy = PREV_INSN (last_insn);
247		rtx return_copy_pat, copy_reg;
248		int copy_start, copy_num;
249		int j;
250
251		if (INSN_P (return_copy))
252		  {
253		    if (GET_CODE (PATTERN (return_copy)) == USE
254			&& GET_CODE (XEXP (PATTERN (return_copy), 0)) == REG
255			&& (FUNCTION_VALUE_REGNO_P
256			    (REGNO (XEXP (PATTERN (return_copy), 0)))))
257		      {
258			maybe_builtin_apply = 1;
259			last_insn = return_copy;
260			continue;
261		      }
262		    /* If the return register is not (in its entirety)
263		       likely spilled, the return copy might be
264		       partially or completely optimized away.  */
265		    return_copy_pat = single_set (return_copy);
266		    if (!return_copy_pat)
267		      {
268			return_copy_pat = PATTERN (return_copy);
269			if (GET_CODE (return_copy_pat) != CLOBBER)
270			  break;
271		      }
272		    copy_reg = SET_DEST (return_copy_pat);
273		    if (GET_CODE (copy_reg) == REG)
274		      copy_start = REGNO (copy_reg);
275		    else if (GET_CODE (copy_reg) == SUBREG
276			     && GET_CODE (SUBREG_REG (copy_reg)) == REG)
277		      copy_start = REGNO (SUBREG_REG (copy_reg));
278		    else
279		      break;
280		    if (copy_start >= FIRST_PSEUDO_REGISTER)
281		      break;
282		    copy_num
283		      = hard_regno_nregs[copy_start][GET_MODE (copy_reg)];
284
285		    /* If the return register is not likely spilled, - as is
286		       the case for floating point on SH4 - then it might
287		       be set by an arithmetic operation that needs a
288		       different mode than the exit block.  */
289		    for (j = n_entities - 1; j >= 0; j--)
290		      {
291			int e = entity_map[j];
292			int mode = MODE_NEEDED (e, return_copy);
293
294			if (mode != num_modes[e] && mode != MODE_EXIT (e))
295			  break;
296		      }
297		    if (j >= 0)
298		      {
299			/* For the SH4, floating point loads depend on fpscr,
300			   thus we might need to put the final mode switch
301			   after the return value copy.  That is still OK,
302			   because a floating point return value does not
303			   conflict with address reloads.  */
304			if (copy_start >= ret_start
305			    && copy_start + copy_num <= ret_end
306			    && OBJECT_P (SET_SRC (return_copy_pat)))
307			  forced_late_switch = 1;
308			break;
309		      }
310
311		    if (copy_start >= ret_start
312			&& copy_start + copy_num <= ret_end)
313		      nregs -= copy_num;
314		    else if (!maybe_builtin_apply
315			     || !FUNCTION_VALUE_REGNO_P (copy_start))
316		      break;
317		    last_insn = return_copy;
318		  }
319		/* ??? Exception handling can lead to the return value
320		   copy being already separated from the return value use,
321		   as in  unwind-dw2.c .
322		   Similarly, conditionally returning without a value,
323		   and conditionally using builtin_return can lead to an
324		   isolated use.  */
325		if (return_copy == BB_HEAD (src_bb))
326		  {
327		    short_block = 1;
328		    break;
329		  }
330		last_insn = return_copy;
331	      }
332	    while (nregs);
333
334	    /* If we didn't see a full return value copy, verify that there
335	       is a plausible reason for this.  If some, but not all of the
336	       return register is likely spilled, we can expect that there
337	       is a copy for the likely spilled part.  */
338	    gcc_assert (!nregs
339			|| forced_late_switch
340			|| short_block
341			|| !(CLASS_LIKELY_SPILLED_P
342			     (REGNO_REG_CLASS (ret_start)))
343			|| (nregs
344			    != hard_regno_nregs[ret_start][GET_MODE (ret_reg)])
345			/* For multi-hard-register floating point
346		   	   values, sometimes the likely-spilled part
347		   	   is ordinarily copied first, then the other
348		   	   part is set with an arithmetic operation.
349		   	   This doesn't actually cause reload
350		   	   failures, so let it pass.  */
351			|| (GET_MODE_CLASS (GET_MODE (ret_reg)) != MODE_INT
352			    && nregs != 1));
353
354	    if (INSN_P (last_insn))
355	      {
356		before_return_copy
357		  = emit_note_before (NOTE_INSN_DELETED, last_insn);
358		/* Instructions preceding LAST_INSN in the same block might
359		   require a different mode than MODE_EXIT, so if we might
360		   have such instructions, keep them in a separate block
361		   from pre_exit.  */
362		if (last_insn != BB_HEAD (src_bb))
363		  src_bb = split_block (src_bb,
364					PREV_INSN (before_return_copy))->dest;
365	      }
366	    else
367	      before_return_copy = last_insn;
368	    pre_exit = split_block (src_bb, before_return_copy)->src;
369	  }
370	else
371	  {
372	    pre_exit = split_edge (eg);
373	    COPY_REG_SET (pre_exit->il.rtl->global_live_at_start, live_at_end);
374	    COPY_REG_SET (pre_exit->il.rtl->global_live_at_end, live_at_end);
375	  }
376      }
377
378  return pre_exit;
379}
380#endif
381
382/* Find all insns that need a particular mode setting, and insert the
383   necessary mode switches.  Return true if we did work.  */
384
385int
386optimize_mode_switching (FILE *file)
387{
388  rtx insn;
389  int e;
390  basic_block bb;
391  int need_commit = 0;
392  sbitmap *kill;
393  struct edge_list *edge_list;
394  static const int num_modes[] = NUM_MODES_FOR_MODE_SWITCHING;
395#define N_ENTITIES ARRAY_SIZE (num_modes)
396  int entity_map[N_ENTITIES];
397  struct bb_info *bb_info[N_ENTITIES];
398  int i, j;
399  int n_entities;
400  int max_num_modes = 0;
401  bool emited = false;
402  basic_block post_entry ATTRIBUTE_UNUSED, pre_exit ATTRIBUTE_UNUSED;
403
404  clear_bb_flags ();
405
406  for (e = N_ENTITIES - 1, n_entities = 0; e >= 0; e--)
407    if (OPTIMIZE_MODE_SWITCHING (e))
408      {
409	int entry_exit_extra = 0;
410
411	/* Create the list of segments within each basic block.
412	   If NORMAL_MODE is defined, allow for two extra
413	   blocks split from the entry and exit block.  */
414#if defined (MODE_ENTRY) && defined (MODE_EXIT)
415	entry_exit_extra = 3;
416#endif
417	bb_info[n_entities]
418	  = xcalloc (last_basic_block + entry_exit_extra, sizeof **bb_info);
419	entity_map[n_entities++] = e;
420	if (num_modes[e] > max_num_modes)
421	  max_num_modes = num_modes[e];
422      }
423
424  if (! n_entities)
425    return 0;
426
427#if defined (MODE_ENTRY) && defined (MODE_EXIT)
428  /* Split the edge from the entry block, so that we can note that
429     there NORMAL_MODE is supplied.  */
430  post_entry = split_edge (single_succ_edge (ENTRY_BLOCK_PTR));
431  pre_exit = create_pre_exit (n_entities, entity_map, num_modes);
432#endif
433
434  /* Create the bitmap vectors.  */
435
436  antic = sbitmap_vector_alloc (last_basic_block, n_entities);
437  transp = sbitmap_vector_alloc (last_basic_block, n_entities);
438  comp = sbitmap_vector_alloc (last_basic_block, n_entities);
439
440  sbitmap_vector_ones (transp, last_basic_block);
441
442  for (j = n_entities - 1; j >= 0; j--)
443    {
444      int e = entity_map[j];
445      int no_mode = num_modes[e];
446      struct bb_info *info = bb_info[j];
447
448      /* Determine what the first use (if any) need for a mode of entity E is.
449	 This will be the mode that is anticipatable for this block.
450	 Also compute the initial transparency settings.  */
451      FOR_EACH_BB (bb)
452	{
453	  struct seginfo *ptr;
454	  int last_mode = no_mode;
455	  HARD_REG_SET live_now;
456
457	  REG_SET_TO_HARD_REG_SET (live_now,
458				   bb->il.rtl->global_live_at_start);
459
460	  /* Pretend the mode is clobbered across abnormal edges.  */
461	  {
462	    edge_iterator ei;
463	    edge e;
464	    FOR_EACH_EDGE (e, ei, bb->preds)
465	      if (e->flags & EDGE_COMPLEX)
466		break;
467	    if (e)
468	      RESET_BIT (transp[bb->index], j);
469	  }
470
471	  for (insn = BB_HEAD (bb);
472	       insn != NULL && insn != NEXT_INSN (BB_END (bb));
473	       insn = NEXT_INSN (insn))
474	    {
475	      if (INSN_P (insn))
476		{
477		  int mode = MODE_NEEDED (e, insn);
478		  rtx link;
479
480		  if (mode != no_mode && mode != last_mode)
481		    {
482		      last_mode = mode;
483		      ptr = new_seginfo (mode, insn, bb->index, live_now);
484		      add_seginfo (info + bb->index, ptr);
485		      RESET_BIT (transp[bb->index], j);
486		    }
487#ifdef MODE_AFTER
488		  last_mode = MODE_AFTER (last_mode, insn);
489#endif
490		  /* Update LIVE_NOW.  */
491		  for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
492		    if (REG_NOTE_KIND (link) == REG_DEAD)
493		      reg_dies (XEXP (link, 0), live_now);
494
495		  note_stores (PATTERN (insn), reg_becomes_live, &live_now);
496		  for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
497		    if (REG_NOTE_KIND (link) == REG_UNUSED)
498		      reg_dies (XEXP (link, 0), live_now);
499		}
500	    }
501
502	  info[bb->index].computing = last_mode;
503	  /* Check for blocks without ANY mode requirements.  */
504	  if (last_mode == no_mode)
505	    {
506	      ptr = new_seginfo (no_mode, BB_END (bb), bb->index, live_now);
507	      add_seginfo (info + bb->index, ptr);
508	    }
509	}
510#if defined (MODE_ENTRY) && defined (MODE_EXIT)
511      {
512	int mode = MODE_ENTRY (e);
513
514	if (mode != no_mode)
515	  {
516	    bb = post_entry;
517
518	    /* By always making this nontransparent, we save
519	       an extra check in make_preds_opaque.  We also
520	       need this to avoid confusing pre_edge_lcm when
521	       antic is cleared but transp and comp are set.  */
522	    RESET_BIT (transp[bb->index], j);
523
524	    /* Insert a fake computing definition of MODE into entry
525	       blocks which compute no mode. This represents the mode on
526	       entry.  */
527	    info[bb->index].computing = mode;
528
529	    if (pre_exit)
530	      info[pre_exit->index].seginfo->mode = MODE_EXIT (e);
531	  }
532      }
533#endif /* NORMAL_MODE */
534    }
535
536  kill = sbitmap_vector_alloc (last_basic_block, n_entities);
537  for (i = 0; i < max_num_modes; i++)
538    {
539      int current_mode[N_ENTITIES];
540      sbitmap *delete;
541      sbitmap *insert;
542
543      /* Set the anticipatable and computing arrays.  */
544      sbitmap_vector_zero (antic, last_basic_block);
545      sbitmap_vector_zero (comp, last_basic_block);
546      for (j = n_entities - 1; j >= 0; j--)
547	{
548	  int m = current_mode[j] = MODE_PRIORITY_TO_MODE (entity_map[j], i);
549	  struct bb_info *info = bb_info[j];
550
551	  FOR_EACH_BB (bb)
552	    {
553	      if (info[bb->index].seginfo->mode == m)
554		SET_BIT (antic[bb->index], j);
555
556	      if (info[bb->index].computing == m)
557		SET_BIT (comp[bb->index], j);
558	    }
559	}
560
561      /* Calculate the optimal locations for the
562	 placement mode switches to modes with priority I.  */
563
564      FOR_EACH_BB (bb)
565	sbitmap_not (kill[bb->index], transp[bb->index]);
566      edge_list = pre_edge_lcm (file, n_entities, transp, comp, antic,
567				kill, &insert, &delete);
568
569      for (j = n_entities - 1; j >= 0; j--)
570	{
571	  /* Insert all mode sets that have been inserted by lcm.  */
572	  int no_mode = num_modes[entity_map[j]];
573
574	  /* Wherever we have moved a mode setting upwards in the flow graph,
575	     the blocks between the new setting site and the now redundant
576	     computation ceases to be transparent for any lower-priority
577	     mode of the same entity.  First set the aux field of each
578	     insertion site edge non-transparent, then propagate the new
579	     non-transparency from the redundant computation upwards till
580	     we hit an insertion site or an already non-transparent block.  */
581	  for (e = NUM_EDGES (edge_list) - 1; e >= 0; e--)
582	    {
583	      edge eg = INDEX_EDGE (edge_list, e);
584	      int mode;
585	      basic_block src_bb;
586	      HARD_REG_SET live_at_edge;
587	      rtx mode_set;
588
589	      eg->aux = 0;
590
591	      if (! TEST_BIT (insert[e], j))
592		continue;
593
594	      eg->aux = (void *)1;
595
596	      mode = current_mode[j];
597	      src_bb = eg->src;
598
599	      REG_SET_TO_HARD_REG_SET (live_at_edge,
600				       src_bb->il.rtl->global_live_at_end);
601
602	      start_sequence ();
603	      EMIT_MODE_SET (entity_map[j], mode, live_at_edge);
604	      mode_set = get_insns ();
605	      end_sequence ();
606
607	      /* Do not bother to insert empty sequence.  */
608	      if (mode_set == NULL_RTX)
609		continue;
610
611	      /* If this is an abnormal edge, we'll insert at the end
612		 of the previous block.  */
613	      if (eg->flags & EDGE_ABNORMAL)
614		{
615		  emited = true;
616		  if (JUMP_P (BB_END (src_bb)))
617		    emit_insn_before (mode_set, BB_END (src_bb));
618		  else
619		    {
620		      /* It doesn't make sense to switch to normal
621		         mode after a CALL_INSN.  The cases in which a
622		         CALL_INSN may have an abnormal edge are
623		         sibcalls and EH edges.  In the case of
624		         sibcalls, the dest basic-block is the
625		         EXIT_BLOCK, that runs in normal mode; it is
626		         assumed that a sibcall insn requires normal
627		         mode itself, so no mode switch would be
628		         required after the call (it wouldn't make
629		         sense, anyway).  In the case of EH edges, EH
630		         entry points also start in normal mode, so a
631		         similar reasoning applies.  */
632		      gcc_assert (NONJUMP_INSN_P (BB_END (src_bb)));
633		      emit_insn_after (mode_set, BB_END (src_bb));
634		    }
635		  bb_info[j][src_bb->index].computing = mode;
636		  RESET_BIT (transp[src_bb->index], j);
637		}
638	      else
639		{
640		  need_commit = 1;
641		  insert_insn_on_edge (mode_set, eg);
642		}
643	    }
644
645	  FOR_EACH_BB_REVERSE (bb)
646	    if (TEST_BIT (delete[bb->index], j))
647	      {
648		make_preds_opaque (bb, j);
649		/* Cancel the 'deleted' mode set.  */
650		bb_info[j][bb->index].seginfo->mode = no_mode;
651	      }
652	}
653
654      sbitmap_vector_free (delete);
655      sbitmap_vector_free (insert);
656      clear_aux_for_edges ();
657      free_edge_list (edge_list);
658    }
659
660  /* Now output the remaining mode sets in all the segments.  */
661  for (j = n_entities - 1; j >= 0; j--)
662    {
663      int no_mode = num_modes[entity_map[j]];
664
665      FOR_EACH_BB_REVERSE (bb)
666	{
667	  struct seginfo *ptr, *next;
668	  for (ptr = bb_info[j][bb->index].seginfo; ptr; ptr = next)
669	    {
670	      next = ptr->next;
671	      if (ptr->mode != no_mode)
672		{
673		  rtx mode_set;
674
675		  start_sequence ();
676		  EMIT_MODE_SET (entity_map[j], ptr->mode, ptr->regs_live);
677		  mode_set = get_insns ();
678		  end_sequence ();
679
680		  /* Insert MODE_SET only if it is nonempty.  */
681		  if (mode_set != NULL_RTX)
682		    {
683		      emited = true;
684		      if (NOTE_P (ptr->insn_ptr)
685			  && (NOTE_LINE_NUMBER (ptr->insn_ptr)
686			      == NOTE_INSN_BASIC_BLOCK))
687			emit_insn_after (mode_set, ptr->insn_ptr);
688		      else
689			emit_insn_before (mode_set, ptr->insn_ptr);
690		    }
691		}
692
693	      free (ptr);
694	    }
695	}
696
697      free (bb_info[j]);
698    }
699
700  /* Finished. Free up all the things we've allocated.  */
701
702  sbitmap_vector_free (kill);
703  sbitmap_vector_free (antic);
704  sbitmap_vector_free (transp);
705  sbitmap_vector_free (comp);
706
707  if (need_commit)
708    commit_edge_insertions ();
709
710#if defined (MODE_ENTRY) && defined (MODE_EXIT)
711  cleanup_cfg (CLEANUP_NO_INSN_DEL);
712#else
713  if (!need_commit && !emited)
714    return 0;
715#endif
716
717  max_regno = max_reg_num ();
718  allocate_reg_info (max_regno, FALSE, FALSE);
719  update_life_info_in_dirty_blocks (UPDATE_LIFE_GLOBAL_RM_NOTES,
720				    (PROP_DEATH_NOTES | PROP_KILL_DEAD_CODE
721				     | PROP_SCAN_DEAD_CODE));
722
723  return 1;
724}
725
726#endif /* OPTIMIZE_MODE_SWITCHING */
727
728static bool
729gate_mode_switching (void)
730{
731#ifdef OPTIMIZE_MODE_SWITCHING
732  return true;
733#else
734  return false;
735#endif
736}
737
738static void
739rest_of_handle_mode_switching (void)
740{
741#ifdef OPTIMIZE_MODE_SWITCHING
742  no_new_pseudos = 0;
743  optimize_mode_switching (NULL);
744  no_new_pseudos = 1;
745#endif /* OPTIMIZE_MODE_SWITCHING */
746}
747
748
749struct tree_opt_pass pass_mode_switching =
750{
751  "mode-sw",                            /* name */
752  gate_mode_switching,                  /* gate */
753  rest_of_handle_mode_switching,        /* execute */
754  NULL,                                 /* sub */
755  NULL,                                 /* next */
756  0,                                    /* static_pass_number */
757  TV_MODE_SWITCH,                       /* tv_id */
758  0,                                    /* properties_required */
759  0,                                    /* properties_provided */
760  0,                                    /* properties_destroyed */
761  0,                                    /* todo_flags_start */
762  TODO_dump_func,                       /* todo_flags_finish */
763  0                                     /* letter */
764};
765