1/* Define control and data flow tables, and regsets.
2   Copyright (C) 1987, 1997, 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#ifndef GCC_BASIC_BLOCK_H
23#define GCC_BASIC_BLOCK_H
24
25#include "bitmap.h"
26#include "sbitmap.h"
27#include "varray.h"
28#include "partition.h"
29#include "hard-reg-set.h"
30#include "predict.h"
31#include "vec.h"
32#include "function.h"
33
34/* Head of register set linked list.  */
35typedef bitmap_head regset_head;
36
37/* A pointer to a regset_head.  */
38typedef bitmap regset;
39
40/* Allocate a register set with oballoc.  */
41#define ALLOC_REG_SET(OBSTACK) BITMAP_ALLOC (OBSTACK)
42
43/* Do any cleanup needed on a regset when it is no longer used.  */
44#define FREE_REG_SET(REGSET) BITMAP_FREE (REGSET)
45
46/* Initialize a new regset.  */
47#define INIT_REG_SET(HEAD) bitmap_initialize (HEAD, &reg_obstack)
48
49/* Clear a register set by freeing up the linked list.  */
50#define CLEAR_REG_SET(HEAD) bitmap_clear (HEAD)
51
52/* Copy a register set to another register set.  */
53#define COPY_REG_SET(TO, FROM) bitmap_copy (TO, FROM)
54
55/* Compare two register sets.  */
56#define REG_SET_EQUAL_P(A, B) bitmap_equal_p (A, B)
57
58/* `and' a register set with a second register set.  */
59#define AND_REG_SET(TO, FROM) bitmap_and_into (TO, FROM)
60
61/* `and' the complement of a register set with a register set.  */
62#define AND_COMPL_REG_SET(TO, FROM) bitmap_and_compl_into (TO, FROM)
63
64/* Inclusive or a register set with a second register set.  */
65#define IOR_REG_SET(TO, FROM) bitmap_ior_into (TO, FROM)
66
67/* Exclusive or a register set with a second register set.  */
68#define XOR_REG_SET(TO, FROM) bitmap_xor_into (TO, FROM)
69
70/* Or into TO the register set FROM1 `and'ed with the complement of FROM2.  */
71#define IOR_AND_COMPL_REG_SET(TO, FROM1, FROM2) \
72  bitmap_ior_and_compl_into (TO, FROM1, FROM2)
73
74/* Clear a single register in a register set.  */
75#define CLEAR_REGNO_REG_SET(HEAD, REG) bitmap_clear_bit (HEAD, REG)
76
77/* Set a single register in a register set.  */
78#define SET_REGNO_REG_SET(HEAD, REG) bitmap_set_bit (HEAD, REG)
79
80/* Return true if a register is set in a register set.  */
81#define REGNO_REG_SET_P(TO, REG) bitmap_bit_p (TO, REG)
82
83/* Copy the hard registers in a register set to the hard register set.  */
84extern void reg_set_to_hard_reg_set (HARD_REG_SET *, bitmap);
85#define REG_SET_TO_HARD_REG_SET(TO, FROM)				\
86do {									\
87  CLEAR_HARD_REG_SET (TO);						\
88  reg_set_to_hard_reg_set (&TO, FROM);					\
89} while (0)
90
91typedef bitmap_iterator reg_set_iterator;
92
93/* Loop over all registers in REGSET, starting with MIN, setting REGNUM to the
94   register number and executing CODE for all registers that are set.  */
95#define EXECUTE_IF_SET_IN_REG_SET(REGSET, MIN, REGNUM, RSI)	\
96  EXECUTE_IF_SET_IN_BITMAP (REGSET, MIN, REGNUM, RSI)
97
98/* Loop over all registers in REGSET1 and REGSET2, starting with MIN, setting
99   REGNUM to the register number and executing CODE for all registers that are
100   set in the first regset and not set in the second.  */
101#define EXECUTE_IF_AND_COMPL_IN_REG_SET(REGSET1, REGSET2, MIN, REGNUM, RSI) \
102  EXECUTE_IF_AND_COMPL_IN_BITMAP (REGSET1, REGSET2, MIN, REGNUM, RSI)
103
104/* Loop over all registers in REGSET1 and REGSET2, starting with MIN, setting
105   REGNUM to the register number and executing CODE for all registers that are
106   set in both regsets.  */
107#define EXECUTE_IF_AND_IN_REG_SET(REGSET1, REGSET2, MIN, REGNUM, RSI) \
108  EXECUTE_IF_AND_IN_BITMAP (REGSET1, REGSET2, MIN, REGNUM, RSI)	\
109
110/* Type we use to hold basic block counters.  Should be at least
111   64bit.  Although a counter cannot be negative, we use a signed
112   type, because erroneous negative counts can be generated when the
113   flow graph is manipulated by various optimizations.  A signed type
114   makes those easy to detect.  */
115typedef HOST_WIDEST_INT gcov_type;
116
117/* Control flow edge information.  */
118struct edge_def GTY(())
119{
120  /* The two blocks at the ends of the edge.  */
121  struct basic_block_def *src;
122  struct basic_block_def *dest;
123
124  /* Instructions queued on the edge.  */
125  union edge_def_insns {
126    rtx GTY ((tag ("0"))) r;
127    tree GTY ((tag ("1"))) t;
128  } GTY ((desc ("ir_type ()"))) insns;
129
130  /* Auxiliary info specific to a pass.  */
131  PTR GTY ((skip (""))) aux;
132
133  /* Location of any goto implicit in the edge, during tree-ssa.  */
134  source_locus goto_locus;
135
136  int flags;			/* see EDGE_* below  */
137  int probability;		/* biased by REG_BR_PROB_BASE */
138  gcov_type count;		/* Expected number of executions calculated
139				   in profile.c  */
140
141  /* The index number corresponding to this edge in the edge vector
142     dest->preds.  */
143  unsigned int dest_idx;
144};
145
146typedef struct edge_def *edge;
147DEF_VEC_P(edge);
148DEF_VEC_ALLOC_P(edge,gc);
149
150#define EDGE_FALLTHRU		1	/* 'Straight line' flow */
151#define EDGE_ABNORMAL		2	/* Strange flow, like computed
152					   label, or eh */
153#define EDGE_ABNORMAL_CALL	4	/* Call with abnormal exit
154					   like an exception, or sibcall */
155#define EDGE_EH			8	/* Exception throw */
156#define EDGE_FAKE		16	/* Not a real edge (profile.c) */
157#define EDGE_DFS_BACK		32	/* A backwards edge */
158#define EDGE_CAN_FALLTHRU	64	/* Candidate for straight line
159					   flow.  */
160#define EDGE_IRREDUCIBLE_LOOP	128	/* Part of irreducible loop.  */
161#define EDGE_SIBCALL		256	/* Edge from sibcall to exit.  */
162#define EDGE_LOOP_EXIT		512	/* Exit of a loop.  */
163#define EDGE_TRUE_VALUE		1024	/* Edge taken when controlling
164					   predicate is nonzero.  */
165#define EDGE_FALSE_VALUE	2048	/* Edge taken when controlling
166					   predicate is zero.  */
167#define EDGE_EXECUTABLE		4096	/* Edge is executable.  Only
168					   valid during SSA-CCP.  */
169#define EDGE_CROSSING		8192    /* Edge crosses between hot
170					   and cold sections, when we
171					   do partitioning.  */
172#define EDGE_ALL_FLAGS	       16383
173
174#define EDGE_COMPLEX	(EDGE_ABNORMAL | EDGE_ABNORMAL_CALL | EDGE_EH)
175
176/* Counter summary from the last set of coverage counts read by
177   profile.c.  */
178extern const struct gcov_ctr_summary *profile_info;
179
180/* Declared in cfgloop.h.  */
181struct loop;
182struct loops;
183
184/* Declared in tree-flow.h.  */
185struct edge_prediction;
186struct rtl_bb_info;
187
188/* A basic block is a sequence of instructions with only entry and
189   only one exit.  If any one of the instructions are executed, they
190   will all be executed, and in sequence from first to last.
191
192   There may be COND_EXEC instructions in the basic block.  The
193   COND_EXEC *instructions* will be executed -- but if the condition
194   is false the conditionally executed *expressions* will of course
195   not be executed.  We don't consider the conditionally executed
196   expression (which might have side-effects) to be in a separate
197   basic block because the program counter will always be at the same
198   location after the COND_EXEC instruction, regardless of whether the
199   condition is true or not.
200
201   Basic blocks need not start with a label nor end with a jump insn.
202   For example, a previous basic block may just "conditionally fall"
203   into the succeeding basic block, and the last basic block need not
204   end with a jump insn.  Block 0 is a descendant of the entry block.
205
206   A basic block beginning with two labels cannot have notes between
207   the labels.
208
209   Data for jump tables are stored in jump_insns that occur in no
210   basic block even though these insns can follow or precede insns in
211   basic blocks.  */
212
213/* Basic block information indexed by block number.  */
214struct basic_block_def GTY((chain_next ("%h.next_bb"), chain_prev ("%h.prev_bb")))
215{
216  /* Pointers to the first and last trees of the block.  */
217  tree stmt_list;
218
219  /* The edges into and out of the block.  */
220  VEC(edge,gc) *preds;
221  VEC(edge,gc) *succs;
222
223  /* Auxiliary info specific to a pass.  */
224  PTR GTY ((skip (""))) aux;
225
226  /* Innermost loop containing the block.  */
227  struct loop * GTY ((skip (""))) loop_father;
228
229  /* The dominance and postdominance information node.  */
230  struct et_node * GTY ((skip (""))) dom[2];
231
232  /* Previous and next blocks in the chain.  */
233  struct basic_block_def *prev_bb;
234  struct basic_block_def *next_bb;
235
236  union basic_block_il_dependent {
237      struct rtl_bb_info * GTY ((tag ("1"))) rtl;
238    } GTY ((desc ("((%1.flags & BB_RTL) != 0)"))) il;
239
240  /* Chain of PHI nodes for this block.  */
241  tree phi_nodes;
242
243  /* A list of predictions.  */
244  struct edge_prediction *predictions;
245
246  /* Expected number of executions: calculated in profile.c.  */
247  gcov_type count;
248
249  /* The index of this block.  */
250  int index;
251
252  /* The loop depth of this block.  */
253  int loop_depth;
254
255  /* Expected frequency.  Normalized to be in range 0 to BB_FREQ_MAX.  */
256  int frequency;
257
258  /* Various flags.  See BB_* below.  */
259  int flags;
260};
261
262struct rtl_bb_info GTY(())
263{
264  /* The first and last insns of the block.  */
265  rtx head_;
266  rtx end_;
267
268  /* The registers that are live on entry to this block.  */
269  bitmap GTY ((skip (""))) global_live_at_start;
270
271  /* The registers that are live on exit from this block.  */
272  bitmap GTY ((skip (""))) global_live_at_end;
273
274  /* In CFGlayout mode points to insn notes/jumptables to be placed just before
275     and after the block.   */
276  rtx header;
277  rtx footer;
278
279  /* This field is used by the bb-reorder and tracer passes.  */
280  int visited;
281};
282
283typedef struct basic_block_def *basic_block;
284
285DEF_VEC_P(basic_block);
286DEF_VEC_ALLOC_P(basic_block,gc);
287DEF_VEC_ALLOC_P(basic_block,heap);
288
289#define BB_FREQ_MAX 10000
290
291/* Masks for basic_block.flags.
292
293   BB_HOT_PARTITION and BB_COLD_PARTITION should be preserved throughout
294   the compilation, so they are never cleared.
295
296   All other flags may be cleared by clear_bb_flags().  It is generally
297   a bad idea to rely on any flags being up-to-date.  */
298
299enum bb_flags
300{
301
302  /* Set if insns in BB have are modified.  Used for updating liveness info.  */
303  BB_DIRTY = 1,
304
305  /* Only set on blocks that have just been created by create_bb.  */
306  BB_NEW = 2,
307
308  /* Set by find_unreachable_blocks.  Do not rely on this being set in any
309     pass.  */
310  BB_REACHABLE = 4,
311
312  /* Set for blocks in an irreducible loop by loop analysis.  */
313  BB_IRREDUCIBLE_LOOP = 8,
314
315  /* Set on blocks that may actually not be single-entry single-exit block.  */
316  BB_SUPERBLOCK = 16,
317
318  /* Set on basic blocks that the scheduler should not touch.  This is used
319     by SMS to prevent other schedulers from messing with the loop schedule.  */
320  BB_DISABLE_SCHEDULE = 32,
321
322  /* Set on blocks that should be put in a hot section.  */
323  BB_HOT_PARTITION = 64,
324
325  /* Set on blocks that should be put in a cold section.  */
326  BB_COLD_PARTITION = 128,
327
328  /* Set on block that was duplicated.  */
329  BB_DUPLICATED = 256,
330
331  /* Set on blocks that are in RTL format.  */
332  BB_RTL = 1024,
333
334  /* Set on blocks that are forwarder blocks.
335     Only used in cfgcleanup.c.  */
336  BB_FORWARDER_BLOCK = 2048,
337
338  /* Set on blocks that cannot be threaded through.
339     Only used in cfgcleanup.c.  */
340  BB_NONTHREADABLE_BLOCK = 4096
341};
342
343/* Dummy flag for convenience in the hot/cold partitioning code.  */
344#define BB_UNPARTITIONED	0
345
346/* Partitions, to be used when partitioning hot and cold basic blocks into
347   separate sections.  */
348#define BB_PARTITION(bb) ((bb)->flags & (BB_HOT_PARTITION|BB_COLD_PARTITION))
349#define BB_SET_PARTITION(bb, part) do {					\
350  basic_block bb_ = (bb);						\
351  bb_->flags = ((bb_->flags & ~(BB_HOT_PARTITION|BB_COLD_PARTITION))	\
352		| (part));						\
353} while (0)
354
355#define BB_COPY_PARTITION(dstbb, srcbb) \
356  BB_SET_PARTITION (dstbb, BB_PARTITION (srcbb))
357
358/* A structure to group all the per-function control flow graph data.
359   The x_* prefixing is necessary because otherwise references to the
360   fields of this struct are interpreted as the defines for backward
361   source compatibility following the definition of this struct.  */
362struct control_flow_graph GTY(())
363{
364  /* Block pointers for the exit and entry of a function.
365     These are always the head and tail of the basic block list.  */
366  basic_block x_entry_block_ptr;
367  basic_block x_exit_block_ptr;
368
369  /* Index by basic block number, get basic block struct info.  */
370  VEC(basic_block,gc) *x_basic_block_info;
371
372  /* Number of basic blocks in this flow graph.  */
373  int x_n_basic_blocks;
374
375  /* Number of edges in this flow graph.  */
376  int x_n_edges;
377
378  /* The first free basic block number.  */
379  int x_last_basic_block;
380
381  /* Mapping of labels to their associated blocks.  At present
382     only used for the tree CFG.  */
383  VEC(basic_block,gc) *x_label_to_block_map;
384
385  enum profile_status {
386    PROFILE_ABSENT,
387    PROFILE_GUESSED,
388    PROFILE_READ
389  } x_profile_status;
390};
391
392/* Defines for accessing the fields of the CFG structure for function FN.  */
393#define ENTRY_BLOCK_PTR_FOR_FUNCTION(FN)     ((FN)->cfg->x_entry_block_ptr)
394#define EXIT_BLOCK_PTR_FOR_FUNCTION(FN)	     ((FN)->cfg->x_exit_block_ptr)
395#define basic_block_info_for_function(FN)    ((FN)->cfg->x_basic_block_info)
396#define n_basic_blocks_for_function(FN)	     ((FN)->cfg->x_n_basic_blocks)
397#define n_edges_for_function(FN)	     ((FN)->cfg->x_n_edges)
398#define last_basic_block_for_function(FN)    ((FN)->cfg->x_last_basic_block)
399#define label_to_block_map_for_function(FN)  ((FN)->cfg->x_label_to_block_map)
400
401#define BASIC_BLOCK_FOR_FUNCTION(FN,N) \
402  (VEC_index (basic_block, basic_block_info_for_function(FN), (N)))
403
404/* Defines for textual backward source compatibility.  */
405#define ENTRY_BLOCK_PTR		(cfun->cfg->x_entry_block_ptr)
406#define EXIT_BLOCK_PTR		(cfun->cfg->x_exit_block_ptr)
407#define basic_block_info	(cfun->cfg->x_basic_block_info)
408#define n_basic_blocks		(cfun->cfg->x_n_basic_blocks)
409#define n_edges			(cfun->cfg->x_n_edges)
410#define last_basic_block	(cfun->cfg->x_last_basic_block)
411#define label_to_block_map	(cfun->cfg->x_label_to_block_map)
412#define profile_status		(cfun->cfg->x_profile_status)
413
414#define BASIC_BLOCK(N)		(VEC_index (basic_block, basic_block_info, (N)))
415#define SET_BASIC_BLOCK(N,BB)	(VEC_replace (basic_block, basic_block_info, (N), (BB)))
416
417/* For iterating over basic blocks.  */
418#define FOR_BB_BETWEEN(BB, FROM, TO, DIR) \
419  for (BB = FROM; BB != TO; BB = BB->DIR)
420
421#define FOR_EACH_BB_FN(BB, FN) \
422  FOR_BB_BETWEEN (BB, (FN)->cfg->x_entry_block_ptr->next_bb, (FN)->cfg->x_exit_block_ptr, next_bb)
423
424#define FOR_EACH_BB(BB) FOR_EACH_BB_FN (BB, cfun)
425
426#define FOR_EACH_BB_REVERSE_FN(BB, FN) \
427  FOR_BB_BETWEEN (BB, (FN)->cfg->x_exit_block_ptr->prev_bb, (FN)->cfg->x_entry_block_ptr, prev_bb)
428
429#define FOR_EACH_BB_REVERSE(BB) FOR_EACH_BB_REVERSE_FN(BB, cfun)
430
431/* For iterating over insns in basic block.  */
432#define FOR_BB_INSNS(BB, INSN)			\
433  for ((INSN) = BB_HEAD (BB);			\
434       (INSN) && (INSN) != NEXT_INSN (BB_END (BB));	\
435       (INSN) = NEXT_INSN (INSN))
436
437#define FOR_BB_INSNS_REVERSE(BB, INSN)		\
438  for ((INSN) = BB_END (BB);			\
439       (INSN) && (INSN) != PREV_INSN (BB_HEAD (BB));	\
440       (INSN) = PREV_INSN (INSN))
441
442/* Cycles through _all_ basic blocks, even the fake ones (entry and
443   exit block).  */
444
445#define FOR_ALL_BB(BB) \
446  for (BB = ENTRY_BLOCK_PTR; BB; BB = BB->next_bb)
447
448#define FOR_ALL_BB_FN(BB, FN) \
449  for (BB = ENTRY_BLOCK_PTR_FOR_FUNCTION (FN); BB; BB = BB->next_bb)
450
451extern bitmap_obstack reg_obstack;
452
453/* Indexed by n, gives number of basic block that  (REG n) is used in.
454   If the value is REG_BLOCK_GLOBAL (-2),
455   it means (REG n) is used in more than one basic block.
456   REG_BLOCK_UNKNOWN (-1) means it hasn't been seen yet so we don't know.
457   This information remains valid for the rest of the compilation
458   of the current function; it is used to control register allocation.  */
459
460#define REG_BLOCK_UNKNOWN -1
461#define REG_BLOCK_GLOBAL -2
462
463#define REG_BASIC_BLOCK(N)				\
464  (VEC_index (reg_info_p, reg_n_info, N)->basic_block)
465
466/* Stuff for recording basic block info.  */
467
468#define BB_HEAD(B)      (B)->il.rtl->head_
469#define BB_END(B)       (B)->il.rtl->end_
470
471/* Special block numbers [markers] for entry and exit.  */
472#define ENTRY_BLOCK (0)
473#define EXIT_BLOCK (1)
474
475/* The two blocks that are always in the cfg.  */
476#define NUM_FIXED_BLOCKS (2)
477
478
479#define BLOCK_NUM(INSN)	      (BLOCK_FOR_INSN (INSN)->index + 0)
480#define set_block_for_insn(INSN, BB)  (BLOCK_FOR_INSN (INSN) = BB)
481
482extern void compute_bb_for_insn (void);
483extern unsigned int free_bb_for_insn (void);
484extern void update_bb_for_insn (basic_block);
485
486extern void free_basic_block_vars (void);
487
488extern void insert_insn_on_edge (rtx, edge);
489
490extern void commit_edge_insertions (void);
491extern void commit_edge_insertions_watch_calls (void);
492
493extern void remove_fake_edges (void);
494extern void remove_fake_exit_edges (void);
495extern void add_noreturn_fake_exit_edges (void);
496extern void connect_infinite_loops_to_exit (void);
497extern edge unchecked_make_edge (basic_block, basic_block, int);
498extern edge cached_make_edge (sbitmap, basic_block, basic_block, int);
499extern edge make_edge (basic_block, basic_block, int);
500extern edge make_single_succ_edge (basic_block, basic_block, int);
501extern void remove_edge (edge);
502extern void redirect_edge_succ (edge, basic_block);
503extern edge redirect_edge_succ_nodup (edge, basic_block);
504extern void redirect_edge_pred (edge, basic_block);
505extern basic_block create_basic_block_structure (rtx, rtx, rtx, basic_block);
506extern void clear_bb_flags (void);
507extern int post_order_compute (int *, bool);
508extern int pre_and_rev_post_order_compute (int *, int *, bool);
509extern int dfs_enumerate_from (basic_block, int,
510			       bool (*)(basic_block, void *),
511			       basic_block *, int, void *);
512extern void compute_dominance_frontiers (bitmap *);
513extern void dump_bb_info (basic_block, bool, bool, int, const char *, FILE *);
514extern void dump_edge_info (FILE *, edge, int);
515extern void brief_dump_cfg (FILE *);
516extern void clear_edges (void);
517extern rtx first_insn_after_basic_block_note (basic_block);
518extern void scale_bbs_frequencies_int (basic_block *, int, int, int);
519extern void scale_bbs_frequencies_gcov_type (basic_block *, int, gcov_type,
520					     gcov_type);
521
522/* Structure to group all of the information to process IF-THEN and
523   IF-THEN-ELSE blocks for the conditional execution support.  This
524   needs to be in a public file in case the IFCVT macros call
525   functions passing the ce_if_block data structure.  */
526
527typedef struct ce_if_block
528{
529  basic_block test_bb;			/* First test block.  */
530  basic_block then_bb;			/* THEN block.  */
531  basic_block else_bb;			/* ELSE block or NULL.  */
532  basic_block join_bb;			/* Join THEN/ELSE blocks.  */
533  basic_block last_test_bb;		/* Last bb to hold && or || tests.  */
534  int num_multiple_test_blocks;		/* # of && and || basic blocks.  */
535  int num_and_and_blocks;		/* # of && blocks.  */
536  int num_or_or_blocks;			/* # of || blocks.  */
537  int num_multiple_test_insns;		/* # of insns in && and || blocks.  */
538  int and_and_p;			/* Complex test is &&.  */
539  int num_then_insns;			/* # of insns in THEN block.  */
540  int num_else_insns;			/* # of insns in ELSE block.  */
541  int pass;				/* Pass number.  */
542
543#ifdef IFCVT_EXTRA_FIELDS
544  IFCVT_EXTRA_FIELDS			/* Any machine dependent fields.  */
545#endif
546
547} ce_if_block_t;
548
549/* This structure maintains an edge list vector.  */
550struct edge_list
551{
552  int num_blocks;
553  int num_edges;
554  edge *index_to_edge;
555};
556
557/* The base value for branch probability notes and edge probabilities.  */
558#define REG_BR_PROB_BASE  10000
559
560/* This is the value which indicates no edge is present.  */
561#define EDGE_INDEX_NO_EDGE	-1
562
563/* EDGE_INDEX returns an integer index for an edge, or EDGE_INDEX_NO_EDGE
564   if there is no edge between the 2 basic blocks.  */
565#define EDGE_INDEX(el, pred, succ) (find_edge_index ((el), (pred), (succ)))
566
567/* INDEX_EDGE_PRED_BB and INDEX_EDGE_SUCC_BB return a pointer to the basic
568   block which is either the pred or succ end of the indexed edge.  */
569#define INDEX_EDGE_PRED_BB(el, index)	((el)->index_to_edge[(index)]->src)
570#define INDEX_EDGE_SUCC_BB(el, index)	((el)->index_to_edge[(index)]->dest)
571
572/* INDEX_EDGE returns a pointer to the edge.  */
573#define INDEX_EDGE(el, index)           ((el)->index_to_edge[(index)])
574
575/* Number of edges in the compressed edge list.  */
576#define NUM_EDGES(el)			((el)->num_edges)
577
578/* BB is assumed to contain conditional jump.  Return the fallthru edge.  */
579#define FALLTHRU_EDGE(bb)		(EDGE_SUCC ((bb), 0)->flags & EDGE_FALLTHRU \
580					 ? EDGE_SUCC ((bb), 0) : EDGE_SUCC ((bb), 1))
581
582/* BB is assumed to contain conditional jump.  Return the branch edge.  */
583#define BRANCH_EDGE(bb)			(EDGE_SUCC ((bb), 0)->flags & EDGE_FALLTHRU \
584					 ? EDGE_SUCC ((bb), 1) : EDGE_SUCC ((bb), 0))
585
586/* Return expected execution frequency of the edge E.  */
587#define EDGE_FREQUENCY(e)		(((e)->src->frequency \
588					  * (e)->probability \
589					  + REG_BR_PROB_BASE / 2) \
590					 / REG_BR_PROB_BASE)
591
592/* Return nonzero if edge is critical.  */
593#define EDGE_CRITICAL_P(e)		(EDGE_COUNT ((e)->src->succs) >= 2 \
594					 && EDGE_COUNT ((e)->dest->preds) >= 2)
595
596#define EDGE_COUNT(ev)			VEC_length (edge, (ev))
597#define EDGE_I(ev,i)			VEC_index  (edge, (ev), (i))
598#define EDGE_PRED(bb,i)			VEC_index  (edge, (bb)->preds, (i))
599#define EDGE_SUCC(bb,i)			VEC_index  (edge, (bb)->succs, (i))
600
601/* Returns true if BB has precisely one successor.  */
602
603static inline bool
604single_succ_p (basic_block bb)
605{
606  return EDGE_COUNT (bb->succs) == 1;
607}
608
609/* Returns true if BB has precisely one predecessor.  */
610
611static inline bool
612single_pred_p (basic_block bb)
613{
614  return EDGE_COUNT (bb->preds) == 1;
615}
616
617/* Returns the single successor edge of basic block BB.  Aborts if
618   BB does not have exactly one successor.  */
619
620static inline edge
621single_succ_edge (basic_block bb)
622{
623  gcc_assert (single_succ_p (bb));
624  return EDGE_SUCC (bb, 0);
625}
626
627/* Returns the single predecessor edge of basic block BB.  Aborts
628   if BB does not have exactly one predecessor.  */
629
630static inline edge
631single_pred_edge (basic_block bb)
632{
633  gcc_assert (single_pred_p (bb));
634  return EDGE_PRED (bb, 0);
635}
636
637/* Returns the single successor block of basic block BB.  Aborts
638   if BB does not have exactly one successor.  */
639
640static inline basic_block
641single_succ (basic_block bb)
642{
643  return single_succ_edge (bb)->dest;
644}
645
646/* Returns the single predecessor block of basic block BB.  Aborts
647   if BB does not have exactly one predecessor.*/
648
649static inline basic_block
650single_pred (basic_block bb)
651{
652  return single_pred_edge (bb)->src;
653}
654
655/* Iterator object for edges.  */
656
657typedef struct {
658  unsigned index;
659  VEC(edge,gc) **container;
660} edge_iterator;
661
662static inline VEC(edge,gc) *
663ei_container (edge_iterator i)
664{
665  gcc_assert (i.container);
666  return *i.container;
667}
668
669#define ei_start(iter) ei_start_1 (&(iter))
670#define ei_last(iter) ei_last_1 (&(iter))
671
672/* Return an iterator pointing to the start of an edge vector.  */
673static inline edge_iterator
674ei_start_1 (VEC(edge,gc) **ev)
675{
676  edge_iterator i;
677
678  i.index = 0;
679  i.container = ev;
680
681  return i;
682}
683
684/* Return an iterator pointing to the last element of an edge
685   vector.  */
686static inline edge_iterator
687ei_last_1 (VEC(edge,gc) **ev)
688{
689  edge_iterator i;
690
691  i.index = EDGE_COUNT (*ev) - 1;
692  i.container = ev;
693
694  return i;
695}
696
697/* Is the iterator `i' at the end of the sequence?  */
698static inline bool
699ei_end_p (edge_iterator i)
700{
701  return (i.index == EDGE_COUNT (ei_container (i)));
702}
703
704/* Is the iterator `i' at one position before the end of the
705   sequence?  */
706static inline bool
707ei_one_before_end_p (edge_iterator i)
708{
709  return (i.index + 1 == EDGE_COUNT (ei_container (i)));
710}
711
712/* Advance the iterator to the next element.  */
713static inline void
714ei_next (edge_iterator *i)
715{
716  gcc_assert (i->index < EDGE_COUNT (ei_container (*i)));
717  i->index++;
718}
719
720/* Move the iterator to the previous element.  */
721static inline void
722ei_prev (edge_iterator *i)
723{
724  gcc_assert (i->index > 0);
725  i->index--;
726}
727
728/* Return the edge pointed to by the iterator `i'.  */
729static inline edge
730ei_edge (edge_iterator i)
731{
732  return EDGE_I (ei_container (i), i.index);
733}
734
735/* Return an edge pointed to by the iterator.  Do it safely so that
736   NULL is returned when the iterator is pointing at the end of the
737   sequence.  */
738static inline edge
739ei_safe_edge (edge_iterator i)
740{
741  return !ei_end_p (i) ? ei_edge (i) : NULL;
742}
743
744/* Return 1 if we should continue to iterate.  Return 0 otherwise.
745   *Edge P is set to the next edge if we are to continue to iterate
746   and NULL otherwise.  */
747
748static inline bool
749ei_cond (edge_iterator ei, edge *p)
750{
751  if (!ei_end_p (ei))
752    {
753      *p = ei_edge (ei);
754      return 1;
755    }
756  else
757    {
758      *p = NULL;
759      return 0;
760    }
761}
762
763/* This macro serves as a convenient way to iterate each edge in a
764   vector of predecessor or successor edges.  It must not be used when
765   an element might be removed during the traversal, otherwise
766   elements will be missed.  Instead, use a for-loop like that shown
767   in the following pseudo-code:
768
769   FOR (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
770     {
771	IF (e != taken_edge)
772	  remove_edge (e);
773	ELSE
774	  ei_next (&ei);
775     }
776*/
777
778#define FOR_EACH_EDGE(EDGE,ITER,EDGE_VEC)	\
779  for ((ITER) = ei_start ((EDGE_VEC));		\
780       ei_cond ((ITER), &(EDGE));		\
781       ei_next (&(ITER)))
782
783struct edge_list * create_edge_list (void);
784void free_edge_list (struct edge_list *);
785void print_edge_list (FILE *, struct edge_list *);
786void verify_edge_list (FILE *, struct edge_list *);
787int find_edge_index (struct edge_list *, basic_block, basic_block);
788edge find_edge (basic_block, basic_block);
789
790
791enum update_life_extent
792{
793  UPDATE_LIFE_LOCAL = 0,
794  UPDATE_LIFE_GLOBAL = 1,
795  UPDATE_LIFE_GLOBAL_RM_NOTES = 2
796};
797
798/* Flags for life_analysis and update_life_info.  */
799
800#define PROP_DEATH_NOTES	1	/* Create DEAD and UNUSED notes.  */
801#define PROP_LOG_LINKS		2	/* Create LOG_LINKS.  */
802#define PROP_REG_INFO		4	/* Update regs_ever_live et al.  */
803#define PROP_KILL_DEAD_CODE	8	/* Remove dead code.  */
804#define PROP_SCAN_DEAD_CODE	16	/* Scan for dead code.  */
805#define PROP_ALLOW_CFG_CHANGES	32	/* Allow the CFG to be changed
806					   by dead code removal.  */
807#define PROP_AUTOINC		64	/* Create autoinc mem references.  */
808#define PROP_SCAN_DEAD_STORES	128	/* Scan for dead code.  */
809#define PROP_ASM_SCAN		256	/* Internal flag used within flow.c
810					   to flag analysis of asms.  */
811#define PROP_DEAD_INSN		1024	/* Internal flag used within flow.c
812					   to flag analysis of dead insn.  */
813#define PROP_POST_REGSTACK	2048	/* We run after reg-stack and need
814					   to preserve REG_DEAD notes for
815					   stack regs.  */
816#define PROP_FINAL		(PROP_DEATH_NOTES | PROP_LOG_LINKS  \
817				 | PROP_REG_INFO | PROP_KILL_DEAD_CODE  \
818				 | PROP_SCAN_DEAD_CODE | PROP_AUTOINC \
819				 | PROP_ALLOW_CFG_CHANGES \
820				 | PROP_SCAN_DEAD_STORES)
821#define PROP_POSTRELOAD		(PROP_DEATH_NOTES  \
822				 | PROP_KILL_DEAD_CODE  \
823				 | PROP_SCAN_DEAD_CODE \
824				 | PROP_SCAN_DEAD_STORES)
825
826#define CLEANUP_EXPENSIVE	1	/* Do relatively expensive optimizations
827					   except for edge forwarding */
828#define CLEANUP_CROSSJUMP	2	/* Do crossjumping.  */
829#define CLEANUP_POST_REGSTACK	4	/* We run after reg-stack and need
830					   to care REG_DEAD notes.  */
831#define CLEANUP_UPDATE_LIFE	8	/* Keep life information up to date.  */
832#define CLEANUP_THREADING	16	/* Do jump threading.  */
833#define CLEANUP_NO_INSN_DEL	32	/* Do not try to delete trivially dead
834					   insns.  */
835#define CLEANUP_CFGLAYOUT	64	/* Do cleanup in cfglayout mode.  */
836#define CLEANUP_LOG_LINKS	128	/* Update log links.  */
837
838/* The following are ORed in on top of the CLEANUP* flags in calls to
839   struct_equiv_block_eq.  */
840#define STRUCT_EQUIV_START	256	 /* Initializes the search range.  */
841#define STRUCT_EQUIV_RERUN	512	/* Rerun to find register use in
842					   found equivalence.  */
843#define STRUCT_EQUIV_FINAL	1024	/* Make any changes necessary to get
844					   actual equivalence.  */
845#define STRUCT_EQUIV_NEED_FULL_BLOCK 2048 /* struct_equiv_block_eq is required
846					     to match only full blocks  */
847#define STRUCT_EQUIV_MATCH_JUMPS 4096	/* Also include the jumps at the end of the block in the comparison.  */
848
849extern void life_analysis (int);
850extern int update_life_info (sbitmap, enum update_life_extent, int);
851extern int update_life_info_in_dirty_blocks (enum update_life_extent, int);
852extern int count_or_remove_death_notes (sbitmap, int);
853extern int propagate_block (basic_block, regset, regset, regset, int);
854
855struct propagate_block_info;
856extern rtx propagate_one_insn (struct propagate_block_info *, rtx);
857extern struct propagate_block_info *init_propagate_block_info
858 (basic_block, regset, regset, regset, int);
859extern void free_propagate_block_info (struct propagate_block_info *);
860
861/* In lcm.c */
862extern struct edge_list *pre_edge_lcm (int, sbitmap *, sbitmap *,
863				       sbitmap *, sbitmap *, sbitmap **,
864				       sbitmap **);
865extern struct edge_list *pre_edge_rev_lcm (int, sbitmap *,
866					   sbitmap *, sbitmap *,
867					   sbitmap *, sbitmap **,
868					   sbitmap **);
869extern void compute_available (sbitmap *, sbitmap *, sbitmap *, sbitmap *);
870
871/* In predict.c */
872extern void expected_value_to_br_prob (void);
873extern bool maybe_hot_bb_p (basic_block);
874extern bool probably_cold_bb_p (basic_block);
875extern bool probably_never_executed_bb_p (basic_block);
876extern bool tree_predicted_by_p (basic_block, enum br_predictor);
877extern bool rtl_predicted_by_p (basic_block, enum br_predictor);
878extern void tree_predict_edge (edge, enum br_predictor, int);
879extern void rtl_predict_edge (edge, enum br_predictor, int);
880extern void predict_edge_def (edge, enum br_predictor, enum prediction);
881extern void guess_outgoing_edge_probabilities (basic_block);
882extern void remove_predictions_associated_with_edge (edge);
883extern bool edge_probability_reliable_p (edge);
884extern bool br_prob_note_reliable_p (rtx);
885
886/* In flow.c */
887extern void init_flow (void);
888extern void debug_bb (basic_block);
889extern basic_block debug_bb_n (int);
890extern void dump_regset (regset, FILE *);
891extern void debug_regset (regset);
892extern void allocate_reg_life_data (void);
893extern void expunge_block (basic_block);
894extern void link_block (basic_block, basic_block);
895extern void unlink_block (basic_block);
896extern void compact_blocks (void);
897extern basic_block alloc_block (void);
898extern void find_unreachable_blocks (void);
899extern int delete_noop_moves (void);
900extern basic_block force_nonfallthru (edge);
901extern rtx block_label (basic_block);
902extern bool forwarder_block_p (basic_block);
903extern bool purge_all_dead_edges (void);
904extern bool purge_dead_edges (basic_block);
905extern void find_many_sub_basic_blocks (sbitmap);
906extern void rtl_make_eh_edge (sbitmap, basic_block, rtx);
907extern bool can_fallthru (basic_block, basic_block);
908extern bool could_fall_through (basic_block, basic_block);
909extern void flow_nodes_print (const char *, const sbitmap, FILE *);
910extern void flow_edge_list_print (const char *, const edge *, int, FILE *);
911extern void alloc_aux_for_block (basic_block, int);
912extern void alloc_aux_for_blocks (int);
913extern void clear_aux_for_blocks (void);
914extern void free_aux_for_blocks (void);
915extern void alloc_aux_for_edge (edge, int);
916extern void alloc_aux_for_edges (int);
917extern void clear_aux_for_edges (void);
918extern void free_aux_for_edges (void);
919extern void find_basic_blocks (rtx);
920extern bool cleanup_cfg (int);
921extern bool delete_unreachable_blocks (void);
922extern bool merge_seq_blocks (void);
923
924typedef struct conflict_graph_def *conflict_graph;
925
926/* Callback function when enumerating conflicts.  The arguments are
927   the smaller and larger regno in the conflict.  Returns zero if
928   enumeration is to continue, nonzero to halt enumeration.  */
929typedef int (*conflict_graph_enum_fn) (int, int, void *);
930
931
932/* Prototypes of operations on conflict graphs.  */
933
934extern conflict_graph conflict_graph_new
935 (int);
936extern void conflict_graph_delete (conflict_graph);
937extern int conflict_graph_add (conflict_graph, int, int);
938extern int conflict_graph_conflict_p (conflict_graph, int, int);
939extern void conflict_graph_enum (conflict_graph, int, conflict_graph_enum_fn,
940				 void *);
941extern void conflict_graph_merge_regs (conflict_graph, int, int);
942extern void conflict_graph_print (conflict_graph, FILE*);
943extern bool mark_dfs_back_edges (void);
944extern void set_edge_can_fallthru_flag (void);
945extern void update_br_prob_note (basic_block);
946extern void fixup_abnormal_edges (void);
947extern bool inside_basic_block_p (rtx);
948extern bool control_flow_insn_p (rtx);
949extern rtx get_last_bb_insn (basic_block);
950
951/* In bb-reorder.c */
952extern void reorder_basic_blocks (unsigned int);
953
954/* In dominance.c */
955
956enum cdi_direction
957{
958  CDI_DOMINATORS,
959  CDI_POST_DOMINATORS
960};
961
962enum dom_state
963{
964  DOM_NONE,		/* Not computed at all.  */
965  DOM_NO_FAST_QUERY,	/* The data is OK, but the fast query data are not usable.  */
966  DOM_OK		/* Everything is ok.  */
967};
968
969extern enum dom_state dom_computed[2];
970
971extern bool dom_info_available_p (enum cdi_direction);
972extern void calculate_dominance_info (enum cdi_direction);
973extern void free_dominance_info (enum cdi_direction);
974extern basic_block nearest_common_dominator (enum cdi_direction,
975					     basic_block, basic_block);
976extern basic_block nearest_common_dominator_for_set (enum cdi_direction,
977						     bitmap);
978extern void set_immediate_dominator (enum cdi_direction, basic_block,
979				     basic_block);
980extern basic_block get_immediate_dominator (enum cdi_direction, basic_block);
981extern bool dominated_by_p (enum cdi_direction, basic_block, basic_block);
982extern int get_dominated_by (enum cdi_direction, basic_block, basic_block **);
983extern unsigned get_dominated_by_region (enum cdi_direction, basic_block *,
984					 unsigned, basic_block *);
985extern void add_to_dominance_info (enum cdi_direction, basic_block);
986extern void delete_from_dominance_info (enum cdi_direction, basic_block);
987basic_block recount_dominator (enum cdi_direction, basic_block);
988extern void redirect_immediate_dominators (enum cdi_direction, basic_block,
989					   basic_block);
990extern void iterate_fix_dominators (enum cdi_direction, basic_block *, int);
991extern void verify_dominators (enum cdi_direction);
992extern basic_block first_dom_son (enum cdi_direction, basic_block);
993extern basic_block next_dom_son (enum cdi_direction, basic_block);
994unsigned bb_dom_dfs_in (enum cdi_direction, basic_block);
995unsigned bb_dom_dfs_out (enum cdi_direction, basic_block);
996
997extern edge try_redirect_by_replacing_jump (edge, basic_block, bool);
998extern void break_superblocks (void);
999extern void check_bb_profile (basic_block, FILE *);
1000extern void update_bb_profile_for_threading (basic_block, int, gcov_type, edge);
1001extern void init_rtl_bb_info (basic_block);
1002
1003extern void initialize_original_copy_tables (void);
1004extern void free_original_copy_tables (void);
1005extern void set_bb_original (basic_block, basic_block);
1006extern basic_block get_bb_original (basic_block);
1007extern void set_bb_copy (basic_block, basic_block);
1008extern basic_block get_bb_copy (basic_block);
1009
1010extern rtx insert_insn_end_bb_new (rtx, basic_block);
1011
1012#include "cfghooks.h"
1013
1014/* In struct-equiv.c */
1015
1016/* Constants used to size arrays in struct equiv_info (currently only one).
1017   When these limits are exceeded, struct_equiv returns zero.
1018   The maximum number of pseudo registers that are different in the two blocks,
1019   but appear in equivalent places and are dead at the end (or where one of
1020   a pair is dead at the end).  */
1021#define STRUCT_EQUIV_MAX_LOCAL 16
1022/* The maximum number of references to an input register that struct_equiv
1023   can handle.  */
1024
1025/* Structure used to track state during struct_equiv that can be rolled
1026   back when we find we can't match an insn, or if we want to match part
1027   of it in a different way.
1028   This information pertains to the pair of partial blocks that has been
1029   matched so far.  Since this pair is structurally equivalent, this is
1030   conceptually just one partial block expressed in two potentially
1031   different ways.  */
1032struct struct_equiv_checkpoint
1033{
1034  int ninsns;       /* Insns are matched so far.  */
1035  int local_count;  /* Number of block-local registers.  */
1036  int input_count;  /* Number of inputs to the block.  */
1037
1038  /* X_START and Y_START are the first insns (in insn stream order)
1039     of the partial blocks that have been considered for matching so far.
1040     Since we are scanning backwards, they are also the instructions that
1041     are currently considered - or the last ones that have been considered -
1042     for matching (Unless we tracked back to these because a preceding
1043     instruction failed to match).  */
1044  rtx x_start, y_start;
1045
1046  /*  INPUT_VALID indicates if we have actually set up X_INPUT / Y_INPUT
1047      during the current pass; we keep X_INPUT / Y_INPUT around between passes
1048      so that we can match REG_EQUAL / REG_EQUIV notes referring to these.  */
1049  bool input_valid;
1050
1051  /* Some information would be expensive to exactly checkpoint, so we
1052     merely increment VERSION any time information about local
1053     registers, inputs and/or register liveness changes.  When backtracking,
1054     it is decremented for changes that can be undone, and if a discrepancy
1055     remains, NEED_RERUN in the relevant struct equiv_info is set to indicate
1056     that a new pass should be made over the entire block match to get
1057     accurate register information.  */
1058  int version;
1059};
1060
1061/* A struct equiv_info is used to pass information to struct_equiv and
1062   to gather state while two basic blocks are checked for structural
1063   equivalence.  */
1064
1065struct equiv_info
1066{
1067  /* Fields set up by the caller to struct_equiv_block_eq */
1068
1069  basic_block x_block, y_block;  /* The two blocks being matched.  */
1070
1071  /* MODE carries the mode bits from cleanup_cfg if we are called from
1072     try_crossjump_to_edge, and additionally it carries the
1073     STRUCT_EQUIV_* bits described above.  */
1074  int mode;
1075
1076  /* INPUT_COST is the cost that adding an extra input to the matched blocks
1077     is supposed to have, and is taken into account when considering if the
1078     matched sequence should be extended backwards.  input_cost < 0 means
1079     don't accept any inputs at all.  */
1080  int input_cost;
1081
1082
1083  /* Fields to track state inside of struct_equiv_block_eq.  Some of these
1084     are also outputs.  */
1085
1086  /* X_INPUT and Y_INPUT are used by struct_equiv to record a register that
1087     is used as an input parameter, i.e. where different registers are used
1088     as sources.  This is only used for a register that is live at the end
1089     of the blocks, or in some identical code at the end of the blocks;
1090     Inputs that are dead at the end go into X_LOCAL / Y_LOCAL.  */
1091  rtx x_input, y_input;
1092  /* When a previous pass has identified a valid input, INPUT_REG is set
1093     by struct_equiv_block_eq, and it is henceforth replaced in X_BLOCK
1094     for the input.  */
1095  rtx input_reg;
1096
1097  /* COMMON_LIVE keeps track of the registers which are currently live
1098     (as we scan backwards from the end) and have the same numbers in both
1099     blocks.  N.B. a register that is in common_live is unsuitable to become
1100     a local reg.  */
1101  regset common_live;
1102  /* Likewise, X_LOCAL_LIVE / Y_LOCAL_LIVE keep track of registers that are
1103     local to one of the blocks; these registers must not be accepted as
1104     identical when encountered in both blocks.  */
1105  regset x_local_live, y_local_live;
1106
1107  /* EQUIV_USED indicates for which insns a REG_EQUAL or REG_EQUIV note is
1108     being used, to avoid having to backtrack in the next pass, so that we
1109     get accurate life info for this insn then.  For each such insn,
1110     the bit with the number corresponding to the CUR.NINSNS value at the
1111     time of scanning is set.  */
1112  bitmap equiv_used;
1113
1114  /* Current state that can be saved & restored easily.  */
1115  struct struct_equiv_checkpoint cur;
1116  /* BEST_MATCH is used to store the best match so far, weighing the
1117     cost of matched insns COSTS_N_INSNS (CUR.NINSNS) against the cost
1118     CUR.INPUT_COUNT * INPUT_COST of setting up the inputs.  */
1119  struct struct_equiv_checkpoint best_match;
1120  /* If a checkpoint restore failed, or an input conflict newly arises,
1121     NEED_RERUN is set.  This has to be tested by the caller to re-run
1122     the comparison if the match appears otherwise sound.  The state kept in
1123     x_start, y_start, equiv_used and check_input_conflict ensures that
1124     we won't loop indefinitely.  */
1125  bool need_rerun;
1126  /* If there is indication of an input conflict at the end,
1127     CHECK_INPUT_CONFLICT is set so that we'll check for input conflicts
1128     for each insn in the next pass.  This is needed so that we won't discard
1129     a partial match if there is a longer match that has to be abandoned due
1130     to an input conflict.  */
1131  bool check_input_conflict;
1132  /* HAD_INPUT_CONFLICT is set if CHECK_INPUT_CONFLICT was already set and we
1133     have passed a point where there were multiple dying inputs.  This helps
1134     us decide if we should set check_input_conflict for the next pass.  */
1135  bool had_input_conflict;
1136
1137  /* LIVE_UPDATE controls if we want to change any life info at all.  We
1138     set it to false during REG_EQUAL / REG_EUQIV note comparison of the final
1139     pass so that we don't introduce new registers just for the note; if we
1140     can't match the notes without the current register information, we drop
1141     them.  */
1142  bool live_update;
1143
1144  /* X_LOCAL and Y_LOCAL are used to gather register numbers of register pairs
1145     that are local to X_BLOCK and Y_BLOCK, with CUR.LOCAL_COUNT being the index
1146     to the next free entry.  */
1147  rtx x_local[STRUCT_EQUIV_MAX_LOCAL], y_local[STRUCT_EQUIV_MAX_LOCAL];
1148  /* LOCAL_RVALUE is nonzero if the corresponding X_LOCAL / Y_LOCAL entry
1149     was a source operand (including STRICT_LOW_PART) for the last invocation
1150     of struct_equiv mentioning it, zero if it was a destination-only operand.
1151     Since we are scanning backwards, this means the register is input/local
1152     for the (partial) block scanned so far.  */
1153  bool local_rvalue[STRUCT_EQUIV_MAX_LOCAL];
1154
1155
1156  /* Additional fields that are computed for the convenience of the caller.  */
1157
1158  /* DYING_INPUTS is set to the number of local registers that turn out
1159     to be inputs to the (possibly partial) block.  */
1160  int dying_inputs;
1161  /* X_END and Y_END are the last insns in X_BLOCK and Y_BLOCK, respectively,
1162     that are being compared.  A final jump insn will not be included.  */
1163  rtx x_end, y_end;
1164
1165  /* If we are matching tablejumps, X_LABEL in X_BLOCK corresponds to
1166     Y_LABEL in Y_BLOCK.  */
1167  rtx x_label, y_label;
1168
1169};
1170
1171extern bool insns_match_p (rtx, rtx, struct equiv_info *);
1172extern int struct_equiv_block_eq (int, struct equiv_info *);
1173extern bool struct_equiv_init (int, struct equiv_info *);
1174extern bool rtx_equiv_p (rtx *, rtx, int, struct equiv_info *);
1175
1176/* In cfgrtl.c */
1177extern bool condjump_equiv_p (struct equiv_info *, bool);
1178
1179/* Return true when one of the predecessor edges of BB is marked with EDGE_EH.  */
1180static inline bool bb_has_eh_pred (basic_block bb)
1181{
1182  edge e;
1183  edge_iterator ei;
1184
1185  FOR_EACH_EDGE (e, ei, bb->preds)
1186    {
1187      if (e->flags & EDGE_EH)
1188	return true;
1189    }
1190  return false;
1191}
1192
1193#endif /* GCC_BASIC_BLOCK_H */
1194