1 /* Instruction scheduling pass.
2 Copyright (C) 1992, 93-97, 1998 Free Software Foundation, Inc.
3 Contributed by Michael Tiemann (tiemann@cygnus.com)
4 Enhanced by, and currently maintained by, Jim Wilson (wilson@cygnus.com)
6 This file is part of GNU CC.
8 GNU CC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2, or (at your option)
13 GNU CC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GNU CC; see the file COPYING. If not, write to
20 the Free Software Foundation, 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA. */
23 /* Instruction scheduling pass.
25 This pass implements list scheduling within basic blocks. It is
26 run after flow analysis, but before register allocation. The
27 scheduler works as follows:
29 We compute insn priorities based on data dependencies. Flow
30 analysis only creates a fraction of the data-dependencies we must
31 observe: namely, only those dependencies which the combiner can be
32 expected to use. For this pass, we must therefore create the
33 remaining dependencies we need to observe: register dependencies,
34 memory dependencies, dependencies to keep function calls in order,
35 and the dependence between a conditional branch and the setting of
36 condition codes are all dealt with here.
38 The scheduler first traverses the data flow graph, starting with
39 the last instruction, and proceeding to the first, assigning
40 values to insn_priority as it goes. This sorts the instructions
41 topologically by data dependence.
43 Once priorities have been established, we order the insns using
44 list scheduling. This works as follows: starting with a list of
45 all the ready insns, and sorted according to priority number, we
46 schedule the insn from the end of the list by placing its
47 predecessors in the list according to their priority order. We
48 consider this insn scheduled by setting the pointer to the "end" of
49 the list to point to the previous insn. When an insn has no
50 predecessors, we either queue it until sufficient time has elapsed
51 or add it to the ready list. As the instructions are scheduled or
52 when stalls are introduced, the queue advances and dumps insns into
53 the ready list. When all insns down to the lowest priority have
54 been scheduled, the critical path of the basic block has been made
55 as short as possible. The remaining insns are then scheduled in
58 Function unit conflicts are resolved during reverse list scheduling
59 by tracking the time when each insn is committed to the schedule
60 and from that, the time the function units it uses must be free.
61 As insns on the ready list are considered for scheduling, those
62 that would result in a blockage of the already committed insns are
63 queued until no blockage will result. Among the remaining insns on
64 the ready list to be considered, the first one with the largest
65 potential for causing a subsequent blockage is chosen.
67 The following list shows the order in which we want to break ties
68 among insns in the ready list:
70 1. choose insn with lowest conflict cost, ties broken by
71 2. choose insn with the longest path to end of bb, ties broken by
72 3. choose insn that kills the most registers, ties broken by
73 4. choose insn that conflicts with the most ready insns, or finally
74 5. choose insn with lowest UID.
76 Memory references complicate matters. Only if we can be certain
77 that memory references are not part of the data dependency graph
78 (via true, anti, or output dependence), can we move operations past
79 memory references. To first approximation, reads can be done
80 independently, while writes introduce dependencies. Better
81 approximations will yield fewer dependencies.
83 Dependencies set up by memory references are treated in exactly the
84 same way as other dependencies, by using LOG_LINKS.
86 Having optimized the critical path, we may have also unduly
87 extended the lifetimes of some registers. If an operation requires
88 that constants be loaded into registers, it is certainly desirable
89 to load those constants as early as necessary, but no earlier.
90 I.e., it will not do to load up a bunch of registers at the
91 beginning of a basic block only to use them at the end, if they
92 could be loaded later, since this may result in excessive register
95 Note that since branches are never in basic blocks, but only end
96 basic blocks, this pass will not do any branch scheduling. But
97 that is ok, since we can use GNU's delayed branch scheduling
98 pass to take care of this case.
100 Also note that no further optimizations based on algebraic identities
101 are performed, so this pass would be a good one to perform instruction
102 splitting, such as breaking up a multiply instruction into shifts
103 and adds where that is profitable.
105 Given the memory aliasing analysis that this pass should perform,
106 it should be possible to remove redundant stores to memory, and to
107 load values from registers instead of hitting memory.
109 This pass must update information that subsequent passes expect to be
110 correct. Namely: reg_n_refs, reg_n_sets, reg_n_deaths,
111 reg_n_calls_crossed, and reg_live_length. Also, basic_block_head,
114 The information in the line number notes is carefully retained by
115 this pass. Notes that refer to the starting and ending of
116 exception regions are also carefully retained by this pass. All
117 other NOTE insns are grouped in their same relative order at the
118 beginning of basic blocks that have been scheduled. */
123 #include "basic-block.h"
125 #include "hard-reg-set.h"
127 #include "insn-config.h"
128 #include "insn-attr.h"
130 extern char *reg_known_equiv_p
;
131 extern rtx
*reg_known_value
;
133 #ifdef INSN_SCHEDULING
134 /* Arrays set up by scheduling for the same respective purposes as
135 similar-named arrays set up by flow analysis. We work with these
136 arrays during the scheduling pass so we can compare values against
139 Values of these arrays are copied at the end of this pass into the
140 arrays set up by flow analysis. */
141 static int *sched_reg_n_calls_crossed
;
142 static int *sched_reg_live_length
;
144 /* Element N is the next insn that sets (hard or pseudo) register
145 N within the current basic block; or zero, if there is no
146 such insn. Needed for new registers which may be introduced
147 by splitting insns. */
148 static rtx
*reg_last_uses
;
149 static rtx
*reg_last_sets
;
150 static regset reg_pending_sets
;
151 static int reg_pending_sets_all
;
153 /* Vector indexed by INSN_UID giving the original ordering of the insns. */
154 static int *insn_luid
;
155 #define INSN_LUID(INSN) (insn_luid[INSN_UID (INSN)])
157 /* Vector indexed by INSN_UID giving each instruction a priority. */
158 static int *insn_priority
;
159 #define INSN_PRIORITY(INSN) (insn_priority[INSN_UID (INSN)])
161 static short *insn_costs
;
162 #define INSN_COST(INSN) insn_costs[INSN_UID (INSN)]
164 /* Vector indexed by INSN_UID giving an encoding of the function units
166 static short *insn_units
;
167 #define INSN_UNIT(INSN) insn_units[INSN_UID (INSN)]
169 /* Vector indexed by INSN_UID giving an encoding of the blockage range
170 function. The unit and the range are encoded. */
171 static unsigned int *insn_blockage
;
172 #define INSN_BLOCKAGE(INSN) insn_blockage[INSN_UID (INSN)]
174 #define BLOCKAGE_MASK ((1 << BLOCKAGE_BITS) - 1)
175 #define ENCODE_BLOCKAGE(U,R) \
176 ((((U) << UNIT_BITS) << BLOCKAGE_BITS \
177 | MIN_BLOCKAGE_COST (R)) << BLOCKAGE_BITS \
178 | MAX_BLOCKAGE_COST (R))
179 #define UNIT_BLOCKED(B) ((B) >> (2 * BLOCKAGE_BITS))
180 #define BLOCKAGE_RANGE(B) \
181 (((((B) >> BLOCKAGE_BITS) & BLOCKAGE_MASK) << (HOST_BITS_PER_INT / 2)) \
182 | ((B) & BLOCKAGE_MASK))
184 /* Encodings of the `<name>_unit_blockage_range' function. */
185 #define MIN_BLOCKAGE_COST(R) ((R) >> (HOST_BITS_PER_INT / 2))
186 #define MAX_BLOCKAGE_COST(R) ((R) & ((1 << (HOST_BITS_PER_INT / 2)) - 1))
188 #define DONE_PRIORITY -1
189 #define MAX_PRIORITY 0x7fffffff
190 #define TAIL_PRIORITY 0x7ffffffe
191 #define LAUNCH_PRIORITY 0x7f000001
192 #define DONE_PRIORITY_P(INSN) (INSN_PRIORITY (INSN) < 0)
193 #define LOW_PRIORITY_P(INSN) ((INSN_PRIORITY (INSN) & 0x7f000000) == 0)
195 /* Vector indexed by INSN_UID giving number of insns referring to this insn. */
196 static int *insn_ref_count
;
197 #define INSN_REF_COUNT(INSN) (insn_ref_count[INSN_UID (INSN)])
199 /* Vector indexed by INSN_UID giving line-number note in effect for each
200 insn. For line-number notes, this indicates whether the note may be
202 static rtx
*line_note
;
203 #define LINE_NOTE(INSN) (line_note[INSN_UID (INSN)])
205 /* Vector indexed by basic block number giving the starting line-number
206 for each basic block. */
207 static rtx
*line_note_head
;
209 /* List of important notes we must keep around. This is a pointer to the
210 last element in the list. */
211 static rtx note_list
;
213 /* Regsets telling whether a given register is live or dead before the last
214 scheduled insn. Must scan the instructions once before scheduling to
215 determine what registers are live or dead at the end of the block. */
216 static regset bb_dead_regs
;
217 static regset bb_live_regs
;
219 /* Regset telling whether a given register is live after the insn currently
220 being scheduled. Before processing an insn, this is equal to bb_live_regs
221 above. This is used so that we can find registers that are newly born/dead
222 after processing an insn. */
223 static regset old_live_regs
;
225 /* The chain of REG_DEAD notes. REG_DEAD notes are removed from all insns
226 during the initial scan and reused later. If there are not exactly as
227 many REG_DEAD notes in the post scheduled code as there were in the
228 prescheduled code then we trigger an abort because this indicates a bug. */
229 static rtx dead_notes
;
233 /* An instruction is ready to be scheduled when all insns following it
234 have already been scheduled. It is important to ensure that all
235 insns which use its result will not be executed until its result
236 has been computed. An insn is maintained in one of four structures:
238 (P) the "Pending" set of insns which cannot be scheduled until
239 their dependencies have been satisfied.
240 (Q) the "Queued" set of insns that can be scheduled when sufficient
242 (R) the "Ready" list of unscheduled, uncommitted insns.
243 (S) the "Scheduled" list of insns.
245 Initially, all insns are either "Pending" or "Ready" depending on
246 whether their dependencies are satisfied.
248 Insns move from the "Ready" list to the "Scheduled" list as they
249 are committed to the schedule. As this occurs, the insns in the
250 "Pending" list have their dependencies satisfied and move to either
251 the "Ready" list or the "Queued" set depending on whether
252 sufficient time has passed to make them ready. As time passes,
253 insns move from the "Queued" set to the "Ready" list. Insns may
254 move from the "Ready" list to the "Queued" set if they are blocked
255 due to a function unit conflict.
257 The "Pending" list (P) are the insns in the LOG_LINKS of the unscheduled
258 insns, i.e., those that are ready, queued, and pending.
259 The "Queued" set (Q) is implemented by the variable `insn_queue'.
260 The "Ready" list (R) is implemented by the variables `ready' and
262 The "Scheduled" list (S) is the new insn chain built by this pass.
264 The transition (R->S) is implemented in the scheduling loop in
265 `schedule_block' when the best insn to schedule is chosen.
266 The transition (R->Q) is implemented in `schedule_select' when an
267 insn is found to to have a function unit conflict with the already
269 The transitions (P->R and P->Q) are implemented in `schedule_insn' as
270 insns move from the ready list to the scheduled list.
271 The transition (Q->R) is implemented at the top of the scheduling
272 loop in `schedule_block' as time passes or stalls are introduced. */
274 /* Implement a circular buffer to delay instructions until sufficient
275 time has passed. INSN_QUEUE_SIZE is a power of two larger than
276 MAX_BLOCKAGE and MAX_READY_COST computed by genattr.c. This is the
277 longest time an isnsn may be queued. */
278 static rtx insn_queue
[INSN_QUEUE_SIZE
];
279 static int q_ptr
= 0;
280 static int q_size
= 0;
281 #define NEXT_Q(X) (((X)+1) & (INSN_QUEUE_SIZE-1))
282 #define NEXT_Q_AFTER(X,C) (((X)+C) & (INSN_QUEUE_SIZE-1))
284 /* Vector indexed by INSN_UID giving the minimum clock tick at which
285 the insn becomes ready. This is used to note timing constraints for
286 insns in the pending list. */
287 static int *insn_tick
;
288 #define INSN_TICK(INSN) (insn_tick[INSN_UID (INSN)])
290 /* Data structure for keeping track of register information
291 during that register's life. */
300 /* Forward declarations. */
301 static void add_dependence
PROTO((rtx
, rtx
, enum reg_note
));
302 static void remove_dependence
PROTO((rtx
, rtx
));
303 static rtx find_insn_list
PROTO((rtx
, rtx
));
304 static int insn_unit
PROTO((rtx
));
305 static unsigned int blockage_range
PROTO((int, rtx
));
306 static void clear_units
PROTO((void));
307 static void prepare_unit
PROTO((int));
308 static int actual_hazard_this_instance
PROTO((int, int, rtx
, int, int));
309 static void schedule_unit
PROTO((int, rtx
, int));
310 static int actual_hazard
PROTO((int, rtx
, int, int));
311 static int potential_hazard
PROTO((int, rtx
, int));
312 static int insn_cost
PROTO((rtx
, rtx
, rtx
));
313 static int priority
PROTO((rtx
));
314 static void free_pending_lists
PROTO((void));
315 static void add_insn_mem_dependence
PROTO((rtx
*, rtx
*, rtx
, rtx
));
316 static void flush_pending_lists
PROTO((rtx
, int));
317 static void sched_analyze_1
PROTO((rtx
, rtx
));
318 static void sched_analyze_2
PROTO((rtx
, rtx
));
319 static void sched_analyze_insn
PROTO((rtx
, rtx
, rtx
));
320 static int sched_analyze
PROTO((rtx
, rtx
));
321 static void sched_note_set
PROTO((int, rtx
, int));
322 static int rank_for_schedule
PROTO((const GENERIC_PTR
, const GENERIC_PTR
));
323 static void swap_sort
PROTO((rtx
*, int));
324 static void queue_insn
PROTO((rtx
, int));
325 static int birthing_insn_p
PROTO((rtx
));
326 static void adjust_priority
PROTO((rtx
));
327 static int schedule_insn
PROTO((rtx
, rtx
*, int, int));
328 static int schedule_select
PROTO((rtx
*, int, int, FILE *));
329 static void create_reg_dead_note
PROTO((rtx
, rtx
));
330 static void attach_deaths
PROTO((rtx
, rtx
, int));
331 static void attach_deaths_insn
PROTO((rtx
));
332 static rtx unlink_notes
PROTO((rtx
, rtx
));
333 static int new_sometimes_live
PROTO((struct sometimes
*, int, int));
334 static void finish_sometimes_live
PROTO((struct sometimes
*, int));
335 static rtx reemit_notes
PROTO((rtx
, rtx
));
336 static void schedule_block
PROTO((int, FILE *));
337 static rtx regno_use_in
PROTO((int, rtx
));
338 static void split_hard_reg_notes
PROTO((rtx
, rtx
, rtx
, rtx
));
339 static void new_insn_dead_notes
PROTO((rtx
, rtx
, rtx
, rtx
));
340 static void update_n_sets
PROTO((rtx
, int));
341 static void update_flow_info
PROTO((rtx
, rtx
, rtx
, rtx
));
343 /* Main entry point of this file. */
344 void schedule_insns
PROTO((FILE *));
346 #endif /* INSN_SCHEDULING */
348 #define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X)))
350 /* Helper functions for instruction scheduling. */
352 /* Add ELEM wrapped in an INSN_LIST with reg note kind DEP_TYPE to the
353 LOG_LINKS of INSN, if not already there. DEP_TYPE indicates the type
354 of dependence that this link represents. */
357 add_dependence (insn
, elem
, dep_type
)
360 enum reg_note dep_type
;
364 /* Don't depend an insn on itself. */
368 /* If elem is part of a sequence that must be scheduled together, then
369 make the dependence point to the last insn of the sequence.
370 When HAVE_cc0, it is possible for NOTEs to exist between users and
371 setters of the condition codes, so we must skip past notes here.
372 Otherwise, NOTEs are impossible here. */
374 next
= NEXT_INSN (elem
);
377 while (next
&& GET_CODE (next
) == NOTE
)
378 next
= NEXT_INSN (next
);
381 if (next
&& SCHED_GROUP_P (next
)
382 && GET_CODE (next
) != CODE_LABEL
)
384 /* Notes will never intervene here though, so don't bother checking
386 /* We must reject CODE_LABELs, so that we don't get confused by one
387 that has LABEL_PRESERVE_P set, which is represented by the same
388 bit in the rtl as SCHED_GROUP_P. A CODE_LABEL can never be
390 while (NEXT_INSN (next
) && SCHED_GROUP_P (NEXT_INSN (next
))
391 && GET_CODE (NEXT_INSN (next
)) != CODE_LABEL
)
392 next
= NEXT_INSN (next
);
394 /* Again, don't depend an insn on itself. */
398 /* Make the dependence to NEXT, the last insn of the group, instead
399 of the original ELEM. */
403 /* Check that we don't already have this dependence. */
404 for (link
= LOG_LINKS (insn
); link
; link
= XEXP (link
, 1))
405 if (XEXP (link
, 0) == elem
)
407 /* If this is a more restrictive type of dependence than the existing
408 one, then change the existing dependence to this type. */
409 if ((int) dep_type
< (int) REG_NOTE_KIND (link
))
410 PUT_REG_NOTE_KIND (link
, dep_type
);
413 /* Might want to check one level of transitivity to save conses. */
415 link
= rtx_alloc (INSN_LIST
);
416 /* Insn dependency, not data dependency. */
417 PUT_REG_NOTE_KIND (link
, dep_type
);
418 XEXP (link
, 0) = elem
;
419 XEXP (link
, 1) = LOG_LINKS (insn
);
420 LOG_LINKS (insn
) = link
;
423 /* Remove ELEM wrapped in an INSN_LIST from the LOG_LINKS
424 of INSN. Abort if not found. */
427 remove_dependence (insn
, elem
)
434 for (prev
= 0, link
= LOG_LINKS (insn
); link
; link
= XEXP (link
, 1))
436 if (XEXP (link
, 0) == elem
)
438 RTX_INTEGRATED_P (link
) = 1;
440 XEXP (prev
, 1) = XEXP (link
, 1);
442 LOG_LINKS (insn
) = XEXP (link
, 1);
454 #ifndef INSN_SCHEDULING
456 schedule_insns (dump_file
)
465 /* Computation of memory dependencies. */
467 /* The *_insns and *_mems are paired lists. Each pending memory operation
468 will have a pointer to the MEM rtx on one list and a pointer to the
469 containing insn on the other list in the same place in the list. */
471 /* We can't use add_dependence like the old code did, because a single insn
472 may have multiple memory accesses, and hence needs to be on the list
473 once for each memory access. Add_dependence won't let you add an insn
474 to a list more than once. */
476 /* An INSN_LIST containing all insns with pending read operations. */
477 static rtx pending_read_insns
;
479 /* An EXPR_LIST containing all MEM rtx's which are pending reads. */
480 static rtx pending_read_mems
;
482 /* An INSN_LIST containing all insns with pending write operations. */
483 static rtx pending_write_insns
;
485 /* An EXPR_LIST containing all MEM rtx's which are pending writes. */
486 static rtx pending_write_mems
;
488 /* Indicates the combined length of the two pending lists. We must prevent
489 these lists from ever growing too large since the number of dependencies
490 produced is at least O(N*N), and execution time is at least O(4*N*N), as
491 a function of the length of these pending lists. */
493 static int pending_lists_length
;
495 /* An INSN_LIST containing all INSN_LISTs allocated but currently unused. */
497 static rtx unused_insn_list
;
499 /* An EXPR_LIST containing all EXPR_LISTs allocated but currently unused. */
501 static rtx unused_expr_list
;
503 /* The last insn upon which all memory references must depend.
504 This is an insn which flushed the pending lists, creating a dependency
505 between it and all previously pending memory references. This creates
506 a barrier (or a checkpoint) which no memory reference is allowed to cross.
508 This includes all non constant CALL_INSNs. When we do interprocedural
509 alias analysis, this restriction can be relaxed.
510 This may also be an INSN that writes memory if the pending lists grow
513 static rtx last_pending_memory_flush
;
515 /* The last function call we have seen. All hard regs, and, of course,
516 the last function call, must depend on this. */
518 static rtx last_function_call
;
520 /* The LOG_LINKS field of this is a list of insns which use a pseudo register
521 that does not already cross a call. We create dependencies between each
522 of those insn and the next call insn, to ensure that they won't cross a call
523 after scheduling is done. */
525 static rtx sched_before_next_call
;
527 /* Pointer to the last instruction scheduled. Used by rank_for_schedule,
528 so that insns independent of the last scheduled insn will be preferred
529 over dependent instructions. */
531 static rtx last_scheduled_insn
;
533 /* Process an insn's memory dependencies. There are four kinds of
536 (0) read dependence: read follows read
537 (1) true dependence: read follows write
538 (2) anti dependence: write follows read
539 (3) output dependence: write follows write
541 We are careful to build only dependencies which actually exist, and
542 use transitivity to avoid building too many links. */
544 /* Return the INSN_LIST containing INSN in LIST, or NULL
545 if LIST does not contain INSN. */
548 find_insn_list (insn
, list
)
554 if (XEXP (list
, 0) == insn
)
556 list
= XEXP (list
, 1);
561 /* Compute the function units used by INSN. This caches the value
562 returned by function_units_used. A function unit is encoded as the
563 unit number if the value is non-negative and the compliment of a
564 mask if the value is negative. A function unit index is the
565 non-negative encoding. */
571 register int unit
= INSN_UNIT (insn
);
575 recog_memoized (insn
);
577 /* A USE insn, or something else we don't need to understand.
578 We can't pass these directly to function_units_used because it will
579 trigger a fatal error for unrecognizable insns. */
580 if (INSN_CODE (insn
) < 0)
584 unit
= function_units_used (insn
);
585 /* Increment non-negative values so we can cache zero. */
586 if (unit
>= 0) unit
++;
588 /* We only cache 16 bits of the result, so if the value is out of
589 range, don't cache it. */
590 if (FUNCTION_UNITS_SIZE
< HOST_BITS_PER_SHORT
592 || (~unit
& ((1 << (HOST_BITS_PER_SHORT
- 1)) - 1)) == 0)
593 INSN_UNIT (insn
) = unit
;
595 return (unit
> 0 ? unit
- 1 : unit
);
598 /* Compute the blockage range for executing INSN on UNIT. This caches
599 the value returned by the blockage_range_function for the unit.
600 These values are encoded in an int where the upper half gives the
601 minimum value and the lower half gives the maximum value. */
603 __inline
static unsigned int
604 blockage_range (unit
, insn
)
608 unsigned int blockage
= INSN_BLOCKAGE (insn
);
611 if (UNIT_BLOCKED (blockage
) != unit
+ 1)
613 range
= function_units
[unit
].blockage_range_function (insn
);
614 /* We only cache the blockage range for one unit and then only if
616 if (HOST_BITS_PER_INT
>= UNIT_BITS
+ 2 * BLOCKAGE_BITS
)
617 INSN_BLOCKAGE (insn
) = ENCODE_BLOCKAGE (unit
+ 1, range
);
620 range
= BLOCKAGE_RANGE (blockage
);
625 /* A vector indexed by function unit instance giving the last insn to use
626 the unit. The value of the function unit instance index for unit U
627 instance I is (U + I * FUNCTION_UNITS_SIZE). */
628 static rtx unit_last_insn
[FUNCTION_UNITS_SIZE
* MAX_MULTIPLICITY
];
630 /* A vector indexed by function unit instance giving the minimum time when
631 the unit will unblock based on the maximum blockage cost. */
632 static int unit_tick
[FUNCTION_UNITS_SIZE
* MAX_MULTIPLICITY
];
634 /* A vector indexed by function unit number giving the number of insns
635 that remain to use the unit. */
636 static int unit_n_insns
[FUNCTION_UNITS_SIZE
];
638 /* Reset the function unit state to the null state. */
643 bzero ((char *) unit_last_insn
, sizeof (unit_last_insn
));
644 bzero ((char *) unit_tick
, sizeof (unit_tick
));
645 bzero ((char *) unit_n_insns
, sizeof (unit_n_insns
));
648 /* Record an insn as one that will use the units encoded by UNIT. */
657 unit_n_insns
[unit
]++;
659 for (i
= 0, unit
= ~unit
; unit
; i
++, unit
>>= 1)
664 /* Return the actual hazard cost of executing INSN on the unit UNIT,
665 instance INSTANCE at time CLOCK if the previous actual hazard cost
669 actual_hazard_this_instance (unit
, instance
, insn
, clock
, cost
)
670 int unit
, instance
, clock
, cost
;
673 int tick
= unit_tick
[instance
];
675 if (tick
- clock
> cost
)
677 /* The scheduler is operating in reverse, so INSN is the executing
678 insn and the unit's last insn is the candidate insn. We want a
679 more exact measure of the blockage if we execute INSN at CLOCK
680 given when we committed the execution of the unit's last insn.
682 The blockage value is given by either the unit's max blockage
683 constant, blockage range function, or blockage function. Use
684 the most exact form for the given unit. */
686 if (function_units
[unit
].blockage_range_function
)
688 if (function_units
[unit
].blockage_function
)
689 tick
+= (function_units
[unit
].blockage_function
690 (insn
, unit_last_insn
[instance
])
691 - function_units
[unit
].max_blockage
);
693 tick
+= ((int) MAX_BLOCKAGE_COST (blockage_range (unit
, insn
))
694 - function_units
[unit
].max_blockage
);
696 if (tick
- clock
> cost
)
702 /* Record INSN as having begun execution on the units encoded by UNIT at
706 schedule_unit (unit
, insn
, clock
)
715 #if MAX_MULTIPLICITY > 1
716 /* Find the first free instance of the function unit and use that
717 one. We assume that one is free. */
718 for (i
= function_units
[unit
].multiplicity
- 1; i
> 0; i
--)
720 if (! actual_hazard_this_instance (unit
, instance
, insn
, clock
, 0))
722 instance
+= FUNCTION_UNITS_SIZE
;
725 unit_last_insn
[instance
] = insn
;
726 unit_tick
[instance
] = (clock
+ function_units
[unit
].max_blockage
);
729 for (i
= 0, unit
= ~unit
; unit
; i
++, unit
>>= 1)
731 schedule_unit (i
, insn
, clock
);
734 /* Return the actual hazard cost of executing INSN on the units encoded by
735 UNIT at time CLOCK if the previous actual hazard cost was COST. */
738 actual_hazard (unit
, insn
, clock
, cost
)
739 int unit
, clock
, cost
;
746 /* Find the instance of the function unit with the minimum hazard. */
748 int best_cost
= actual_hazard_this_instance (unit
, instance
, insn
,
750 #if MAX_MULTIPLICITY > 1
753 if (best_cost
> cost
)
755 for (i
= function_units
[unit
].multiplicity
- 1; i
> 0; i
--)
757 instance
+= FUNCTION_UNITS_SIZE
;
758 this_cost
= actual_hazard_this_instance (unit
, instance
, insn
,
760 if (this_cost
< best_cost
)
762 best_cost
= this_cost
;
763 if (this_cost
<= cost
)
769 cost
= MAX (cost
, best_cost
);
772 for (i
= 0, unit
= ~unit
; unit
; i
++, unit
>>= 1)
774 cost
= actual_hazard (i
, insn
, clock
, cost
);
779 /* Return the potential hazard cost of executing an instruction on the
780 units encoded by UNIT if the previous potential hazard cost was COST.
781 An insn with a large blockage time is chosen in preference to one
782 with a smaller time; an insn that uses a unit that is more likely
783 to be used is chosen in preference to one with a unit that is less
784 used. We are trying to minimize a subsequent actual hazard. */
787 potential_hazard (unit
, insn
, cost
)
792 unsigned int minb
, maxb
;
796 minb
= maxb
= function_units
[unit
].max_blockage
;
799 if (function_units
[unit
].blockage_range_function
)
801 maxb
= minb
= blockage_range (unit
, insn
);
802 maxb
= MAX_BLOCKAGE_COST (maxb
);
803 minb
= MIN_BLOCKAGE_COST (minb
);
808 /* Make the number of instructions left dominate. Make the
809 minimum delay dominate the maximum delay. If all these
810 are the same, use the unit number to add an arbitrary
811 ordering. Other terms can be added. */
812 ncost
= minb
* 0x40 + maxb
;
813 ncost
*= (unit_n_insns
[unit
] - 1) * 0x1000 + unit
;
820 for (i
= 0, unit
= ~unit
; unit
; i
++, unit
>>= 1)
822 cost
= potential_hazard (i
, insn
, cost
);
827 /* Compute cost of executing INSN given the dependence LINK on the insn USED.
828 This is the number of virtual cycles taken between instruction issue and
829 instruction results. */
832 insn_cost (insn
, link
, used
)
833 rtx insn
, link
, used
;
835 register int cost
= INSN_COST (insn
);
839 recog_memoized (insn
);
841 /* A USE insn, or something else we don't need to understand.
842 We can't pass these directly to result_ready_cost because it will
843 trigger a fatal error for unrecognizable insns. */
844 if (INSN_CODE (insn
) < 0)
846 INSN_COST (insn
) = 1;
851 cost
= result_ready_cost (insn
);
856 INSN_COST (insn
) = cost
;
860 /* A USE insn should never require the value used to be computed. This
861 allows the computation of a function's result and parameter values to
862 overlap the return and call. */
863 recog_memoized (used
);
864 if (INSN_CODE (used
) < 0)
865 LINK_COST_FREE (link
) = 1;
867 /* If some dependencies vary the cost, compute the adjustment. Most
868 commonly, the adjustment is complete: either the cost is ignored
869 (in the case of an output- or anti-dependence), or the cost is
870 unchanged. These values are cached in the link as LINK_COST_FREE
871 and LINK_COST_ZERO. */
873 if (LINK_COST_FREE (link
))
876 else if (! LINK_COST_ZERO (link
))
880 ADJUST_COST (used
, link
, insn
, ncost
);
882 LINK_COST_FREE (link
) = ncost
= 1;
884 LINK_COST_ZERO (link
) = 1;
891 /* Compute the priority number for INSN. */
897 if (insn
&& GET_RTX_CLASS (GET_CODE (insn
)) == 'i')
901 int this_priority
= INSN_PRIORITY (insn
);
904 if (this_priority
> 0)
905 return this_priority
;
909 /* Nonzero if these insns must be scheduled together. */
910 if (SCHED_GROUP_P (insn
))
913 while (SCHED_GROUP_P (prev
))
915 prev
= PREV_INSN (prev
);
916 INSN_REF_COUNT (prev
) += 1;
920 for (prev
= LOG_LINKS (insn
); prev
; prev
= XEXP (prev
, 1))
922 rtx x
= XEXP (prev
, 0);
924 /* If this was a duplicate of a dependence we already deleted,
926 if (RTX_INTEGRATED_P (prev
))
929 /* A dependence pointing to a note or deleted insn is always
930 obsolete, because sched_analyze_insn will have created any
931 necessary new dependences which replace it. Notes and deleted
932 insns can be created when instructions are deleted by insn
933 splitting, or by register allocation. */
934 if (GET_CODE (x
) == NOTE
|| INSN_DELETED_P (x
))
936 remove_dependence (insn
, x
);
940 /* Clear the link cost adjustment bits. */
941 LINK_COST_FREE (prev
) = 0;
943 LINK_COST_ZERO (prev
) = 0;
946 /* This priority calculation was chosen because it results in the
947 least instruction movement, and does not hurt the performance
948 of the resulting code compared to the old algorithm.
949 This makes the sched algorithm more stable, which results
950 in better code, because there is less register pressure,
951 cross jumping is more likely to work, and debugging is easier.
953 When all instructions have a latency of 1, there is no need to
954 move any instructions. Subtracting one here ensures that in such
955 cases all instructions will end up with a priority of one, and
956 hence no scheduling will be done.
958 The original code did not subtract the one, and added the
959 insn_cost of the current instruction to its priority (e.g.
960 move the insn_cost call down to the end). */
962 prev_priority
= priority (x
) + insn_cost (x
, prev
, insn
) - 1;
964 if (prev_priority
> max_priority
)
965 max_priority
= prev_priority
;
966 INSN_REF_COUNT (x
) += 1;
969 prepare_unit (insn_unit (insn
));
970 INSN_PRIORITY (insn
) = max_priority
;
971 return INSN_PRIORITY (insn
);
976 /* Remove all INSN_LISTs and EXPR_LISTs from the pending lists and add
977 them to the unused_*_list variables, so that they can be reused. */
980 free_pending_lists ()
982 register rtx link
, prev_link
;
984 if (pending_read_insns
)
986 prev_link
= pending_read_insns
;
987 link
= XEXP (prev_link
, 1);
992 link
= XEXP (link
, 1);
995 XEXP (prev_link
, 1) = unused_insn_list
;
996 unused_insn_list
= pending_read_insns
;
997 pending_read_insns
= 0;
1000 if (pending_write_insns
)
1002 prev_link
= pending_write_insns
;
1003 link
= XEXP (prev_link
, 1);
1008 link
= XEXP (link
, 1);
1011 XEXP (prev_link
, 1) = unused_insn_list
;
1012 unused_insn_list
= pending_write_insns
;
1013 pending_write_insns
= 0;
1016 if (pending_read_mems
)
1018 prev_link
= pending_read_mems
;
1019 link
= XEXP (prev_link
, 1);
1024 link
= XEXP (link
, 1);
1027 XEXP (prev_link
, 1) = unused_expr_list
;
1028 unused_expr_list
= pending_read_mems
;
1029 pending_read_mems
= 0;
1032 if (pending_write_mems
)
1034 prev_link
= pending_write_mems
;
1035 link
= XEXP (prev_link
, 1);
1040 link
= XEXP (link
, 1);
1043 XEXP (prev_link
, 1) = unused_expr_list
;
1044 unused_expr_list
= pending_write_mems
;
1045 pending_write_mems
= 0;
1049 /* Add an INSN and MEM reference pair to a pending INSN_LIST and MEM_LIST.
1050 The MEM is a memory reference contained within INSN, which we are saving
1051 so that we can do memory aliasing on it. */
1054 add_insn_mem_dependence (insn_list
, mem_list
, insn
, mem
)
1055 rtx
*insn_list
, *mem_list
, insn
, mem
;
1059 if (unused_insn_list
)
1061 link
= unused_insn_list
;
1062 unused_insn_list
= XEXP (link
, 1);
1065 link
= rtx_alloc (INSN_LIST
);
1066 XEXP (link
, 0) = insn
;
1067 XEXP (link
, 1) = *insn_list
;
1070 if (unused_expr_list
)
1072 link
= unused_expr_list
;
1073 unused_expr_list
= XEXP (link
, 1);
1076 link
= rtx_alloc (EXPR_LIST
);
1077 XEXP (link
, 0) = mem
;
1078 XEXP (link
, 1) = *mem_list
;
1081 pending_lists_length
++;
1084 /* Make a dependency between every memory reference on the pending lists
1085 and INSN, thus flushing the pending lists. If ONLY_WRITE, don't flush
1089 flush_pending_lists (insn
, only_write
)
1095 while (pending_read_insns
&& ! only_write
)
1097 add_dependence (insn
, XEXP (pending_read_insns
, 0), REG_DEP_ANTI
);
1099 link
= pending_read_insns
;
1100 pending_read_insns
= XEXP (pending_read_insns
, 1);
1101 XEXP (link
, 1) = unused_insn_list
;
1102 unused_insn_list
= link
;
1104 link
= pending_read_mems
;
1105 pending_read_mems
= XEXP (pending_read_mems
, 1);
1106 XEXP (link
, 1) = unused_expr_list
;
1107 unused_expr_list
= link
;
1109 while (pending_write_insns
)
1111 add_dependence (insn
, XEXP (pending_write_insns
, 0), REG_DEP_ANTI
);
1113 link
= pending_write_insns
;
1114 pending_write_insns
= XEXP (pending_write_insns
, 1);
1115 XEXP (link
, 1) = unused_insn_list
;
1116 unused_insn_list
= link
;
1118 link
= pending_write_mems
;
1119 pending_write_mems
= XEXP (pending_write_mems
, 1);
1120 XEXP (link
, 1) = unused_expr_list
;
1121 unused_expr_list
= link
;
1123 pending_lists_length
= 0;
1125 if (last_pending_memory_flush
)
1126 add_dependence (insn
, last_pending_memory_flush
, REG_DEP_ANTI
);
1128 last_pending_memory_flush
= insn
;
1131 /* Analyze a single SET or CLOBBER rtx, X, creating all dependencies generated
1132 by the write to the destination of X, and reads of everything mentioned. */
1135 sched_analyze_1 (x
, insn
)
1140 register rtx dest
= SET_DEST (x
);
1145 while (GET_CODE (dest
) == STRICT_LOW_PART
|| GET_CODE (dest
) == SUBREG
1146 || GET_CODE (dest
) == ZERO_EXTRACT
|| GET_CODE (dest
) == SIGN_EXTRACT
)
1148 if (GET_CODE (dest
) == ZERO_EXTRACT
|| GET_CODE (dest
) == SIGN_EXTRACT
)
1150 /* The second and third arguments are values read by this insn. */
1151 sched_analyze_2 (XEXP (dest
, 1), insn
);
1152 sched_analyze_2 (XEXP (dest
, 2), insn
);
1154 dest
= SUBREG_REG (dest
);
1157 if (GET_CODE (dest
) == REG
)
1161 regno
= REGNO (dest
);
1163 /* A hard reg in a wide mode may really be multiple registers.
1164 If so, mark all of them just like the first. */
1165 if (regno
< FIRST_PSEUDO_REGISTER
)
1167 i
= HARD_REGNO_NREGS (regno
, GET_MODE (dest
));
1172 for (u
= reg_last_uses
[regno
+i
]; u
; u
= XEXP (u
, 1))
1173 add_dependence (insn
, XEXP (u
, 0), REG_DEP_ANTI
);
1174 reg_last_uses
[regno
+ i
] = 0;
1175 if (reg_last_sets
[regno
+ i
])
1176 add_dependence (insn
, reg_last_sets
[regno
+ i
],
1178 SET_REGNO_REG_SET (reg_pending_sets
, regno
+ i
);
1179 if ((call_used_regs
[i
] || global_regs
[i
])
1180 && last_function_call
)
1181 /* Function calls clobber all call_used regs. */
1182 add_dependence (insn
, last_function_call
, REG_DEP_ANTI
);
1189 for (u
= reg_last_uses
[regno
]; u
; u
= XEXP (u
, 1))
1190 add_dependence (insn
, XEXP (u
, 0), REG_DEP_ANTI
);
1191 reg_last_uses
[regno
] = 0;
1192 if (reg_last_sets
[regno
])
1193 add_dependence (insn
, reg_last_sets
[regno
], REG_DEP_OUTPUT
);
1194 SET_REGNO_REG_SET (reg_pending_sets
, regno
);
1196 /* Pseudos that are REG_EQUIV to something may be replaced
1197 by that during reloading. We need only add dependencies for
1198 the address in the REG_EQUIV note. */
1199 if (! reload_completed
1200 && reg_known_equiv_p
[regno
]
1201 && GET_CODE (reg_known_value
[regno
]) == MEM
)
1202 sched_analyze_2 (XEXP (reg_known_value
[regno
], 0), insn
);
1204 /* Don't let it cross a call after scheduling if it doesn't
1205 already cross one. */
1206 if (REG_N_CALLS_CROSSED (regno
) == 0 && last_function_call
)
1207 add_dependence (insn
, last_function_call
, REG_DEP_ANTI
);
1210 else if (GET_CODE (dest
) == MEM
)
1212 /* Writing memory. */
1214 if (pending_lists_length
> 32)
1216 /* Flush all pending reads and writes to prevent the pending lists
1217 from getting any larger. Insn scheduling runs too slowly when
1218 these lists get long. The number 32 was chosen because it
1219 seems like a reasonable number. When compiling GCC with itself,
1220 this flush occurs 8 times for sparc, and 10 times for m88k using
1222 flush_pending_lists (insn
, 0);
1226 rtx pending
, pending_mem
;
1228 pending
= pending_read_insns
;
1229 pending_mem
= pending_read_mems
;
1232 /* If a dependency already exists, don't create a new one. */
1233 if (! find_insn_list (XEXP (pending
, 0), LOG_LINKS (insn
)))
1234 if (anti_dependence (XEXP (pending_mem
, 0), dest
))
1235 add_dependence (insn
, XEXP (pending
, 0), REG_DEP_ANTI
);
1237 pending
= XEXP (pending
, 1);
1238 pending_mem
= XEXP (pending_mem
, 1);
1241 pending
= pending_write_insns
;
1242 pending_mem
= pending_write_mems
;
1245 /* If a dependency already exists, don't create a new one. */
1246 if (! find_insn_list (XEXP (pending
, 0), LOG_LINKS (insn
)))
1247 if (output_dependence (XEXP (pending_mem
, 0), dest
))
1248 add_dependence (insn
, XEXP (pending
, 0), REG_DEP_OUTPUT
);
1250 pending
= XEXP (pending
, 1);
1251 pending_mem
= XEXP (pending_mem
, 1);
1254 if (last_pending_memory_flush
)
1255 add_dependence (insn
, last_pending_memory_flush
, REG_DEP_ANTI
);
1257 add_insn_mem_dependence (&pending_write_insns
, &pending_write_mems
,
1260 sched_analyze_2 (XEXP (dest
, 0), insn
);
1263 /* Analyze reads. */
1264 if (GET_CODE (x
) == SET
)
1265 sched_analyze_2 (SET_SRC (x
), insn
);
1268 /* Analyze the uses of memory and registers in rtx X in INSN. */
1271 sched_analyze_2 (x
, insn
)
1277 register enum rtx_code code
;
1283 code
= GET_CODE (x
);
1292 /* Ignore constants. Note that we must handle CONST_DOUBLE here
1293 because it may have a cc0_rtx in its CONST_DOUBLE_CHAIN field, but
1294 this does not mean that this insn is using cc0. */
1302 /* User of CC0 depends on immediately preceding insn. */
1303 SCHED_GROUP_P (insn
) = 1;
1305 /* There may be a note before this insn now, but all notes will
1306 be removed before we actually try to schedule the insns, so
1307 it won't cause a problem later. We must avoid it here though. */
1308 prev
= prev_nonnote_insn (insn
);
1310 /* Make a copy of all dependencies on the immediately previous insn,
1311 and add to this insn. This is so that all the dependencies will
1312 apply to the group. Remove an explicit dependence on this insn
1313 as SCHED_GROUP_P now represents it. */
1315 if (find_insn_list (prev
, LOG_LINKS (insn
)))
1316 remove_dependence (insn
, prev
);
1318 for (link
= LOG_LINKS (prev
); link
; link
= XEXP (link
, 1))
1319 add_dependence (insn
, XEXP (link
, 0), REG_NOTE_KIND (link
));
1327 int regno
= REGNO (x
);
1328 if (regno
< FIRST_PSEUDO_REGISTER
)
1332 i
= HARD_REGNO_NREGS (regno
, GET_MODE (x
));
1335 reg_last_uses
[regno
+ i
]
1336 = gen_rtx_INSN_LIST (VOIDmode
,
1337 insn
, reg_last_uses
[regno
+ i
]);
1338 if (reg_last_sets
[regno
+ i
])
1339 add_dependence (insn
, reg_last_sets
[regno
+ i
], 0);
1340 if ((call_used_regs
[regno
+ i
] || global_regs
[regno
+ i
])
1341 && last_function_call
)
1342 /* Function calls clobber all call_used regs. */
1343 add_dependence (insn
, last_function_call
, REG_DEP_ANTI
);
1348 reg_last_uses
[regno
]
1349 = gen_rtx_INSN_LIST (VOIDmode
, insn
, reg_last_uses
[regno
]);
1350 if (reg_last_sets
[regno
])
1351 add_dependence (insn
, reg_last_sets
[regno
], 0);
1353 /* Pseudos that are REG_EQUIV to something may be replaced
1354 by that during reloading. We need only add dependencies for
1355 the address in the REG_EQUIV note. */
1356 if (! reload_completed
1357 && reg_known_equiv_p
[regno
]
1358 && GET_CODE (reg_known_value
[regno
]) == MEM
)
1359 sched_analyze_2 (XEXP (reg_known_value
[regno
], 0), insn
);
1361 /* If the register does not already cross any calls, then add this
1362 insn to the sched_before_next_call list so that it will still
1363 not cross calls after scheduling. */
1364 if (REG_N_CALLS_CROSSED (regno
) == 0)
1365 add_dependence (sched_before_next_call
, insn
, REG_DEP_ANTI
);
1372 /* Reading memory. */
1374 rtx pending
, pending_mem
;
1376 pending
= pending_read_insns
;
1377 pending_mem
= pending_read_mems
;
1380 /* If a dependency already exists, don't create a new one. */
1381 if (! find_insn_list (XEXP (pending
, 0), LOG_LINKS (insn
)))
1382 if (read_dependence (XEXP (pending_mem
, 0), x
))
1383 add_dependence (insn
, XEXP (pending
, 0), REG_DEP_ANTI
);
1385 pending
= XEXP (pending
, 1);
1386 pending_mem
= XEXP (pending_mem
, 1);
1389 pending
= pending_write_insns
;
1390 pending_mem
= pending_write_mems
;
1393 /* If a dependency already exists, don't create a new one. */
1394 if (! find_insn_list (XEXP (pending
, 0), LOG_LINKS (insn
)))
1395 if (true_dependence (XEXP (pending_mem
, 0), VOIDmode
,
1397 add_dependence (insn
, XEXP (pending
, 0), 0);
1399 pending
= XEXP (pending
, 1);
1400 pending_mem
= XEXP (pending_mem
, 1);
1402 if (last_pending_memory_flush
)
1403 add_dependence (insn
, last_pending_memory_flush
, REG_DEP_ANTI
);
1405 /* Always add these dependencies to pending_reads, since
1406 this insn may be followed by a write. */
1407 add_insn_mem_dependence (&pending_read_insns
, &pending_read_mems
,
1410 /* Take advantage of tail recursion here. */
1411 sched_analyze_2 (XEXP (x
, 0), insn
);
1417 case UNSPEC_VOLATILE
:
1422 /* Traditional and volatile asm instructions must be considered to use
1423 and clobber all hard registers, all pseudo-registers and all of
1424 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
1426 Consider for instance a volatile asm that changes the fpu rounding
1427 mode. An insn should not be moved across this even if it only uses
1428 pseudo-regs because it might give an incorrectly rounded result. */
1429 if (code
!= ASM_OPERANDS
|| MEM_VOLATILE_P (x
))
1431 int max_reg
= max_reg_num ();
1432 for (i
= 0; i
< max_reg
; i
++)
1434 for (u
= reg_last_uses
[i
]; u
; u
= XEXP (u
, 1))
1435 add_dependence (insn
, XEXP (u
, 0), REG_DEP_ANTI
);
1436 reg_last_uses
[i
] = 0;
1437 if (reg_last_sets
[i
])
1438 add_dependence (insn
, reg_last_sets
[i
], 0);
1440 reg_pending_sets_all
= 1;
1442 flush_pending_lists (insn
, 0);
1445 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
1446 We can not just fall through here since then we would be confused
1447 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
1448 traditional asms unlike their normal usage. */
1450 if (code
== ASM_OPERANDS
)
1452 for (j
= 0; j
< ASM_OPERANDS_INPUT_LENGTH (x
); j
++)
1453 sched_analyze_2 (ASM_OPERANDS_INPUT (x
, j
), insn
);
1463 /* These both read and modify the result. We must handle them as writes
1464 to get proper dependencies for following instructions. We must handle
1465 them as reads to get proper dependencies from this to previous
1466 instructions. Thus we need to pass them to both sched_analyze_1
1467 and sched_analyze_2. We must call sched_analyze_2 first in order
1468 to get the proper antecedent for the read. */
1469 sched_analyze_2 (XEXP (x
, 0), insn
);
1470 sched_analyze_1 (x
, insn
);
1477 /* Other cases: walk the insn. */
1478 fmt
= GET_RTX_FORMAT (code
);
1479 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
1482 sched_analyze_2 (XEXP (x
, i
), insn
);
1483 else if (fmt
[i
] == 'E')
1484 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
1485 sched_analyze_2 (XVECEXP (x
, i
, j
), insn
);
1489 /* Analyze an INSN with pattern X to find all dependencies. */
1492 sched_analyze_insn (x
, insn
, loop_notes
)
1496 register RTX_CODE code
= GET_CODE (x
);
1498 int maxreg
= max_reg_num ();
1501 if (code
== SET
|| code
== CLOBBER
)
1502 sched_analyze_1 (x
, insn
);
1503 else if (code
== PARALLEL
)
1506 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
1508 code
= GET_CODE (XVECEXP (x
, 0, i
));
1509 if (code
== SET
|| code
== CLOBBER
)
1510 sched_analyze_1 (XVECEXP (x
, 0, i
), insn
);
1512 sched_analyze_2 (XVECEXP (x
, 0, i
), insn
);
1516 sched_analyze_2 (x
, insn
);
1518 /* Mark registers CLOBBERED or used by called function. */
1519 if (GET_CODE (insn
) == CALL_INSN
)
1520 for (link
= CALL_INSN_FUNCTION_USAGE (insn
); link
; link
= XEXP (link
, 1))
1522 if (GET_CODE (XEXP (link
, 0)) == CLOBBER
)
1523 sched_analyze_1 (XEXP (link
, 0), insn
);
1525 sched_analyze_2 (XEXP (link
, 0), insn
);
1528 /* If there is a {LOOP,EHREGION}_{BEG,END} note in the middle of a basic block, then
1529 we must be sure that no instructions are scheduled across it.
1530 Otherwise, the reg_n_refs info (which depends on loop_depth) would
1531 become incorrect. */
1535 int max_reg
= max_reg_num ();
1538 for (i
= 0; i
< max_reg
; i
++)
1541 for (u
= reg_last_uses
[i
]; u
; u
= XEXP (u
, 1))
1542 add_dependence (insn
, XEXP (u
, 0), REG_DEP_ANTI
);
1543 reg_last_uses
[i
] = 0;
1544 if (reg_last_sets
[i
])
1545 add_dependence (insn
, reg_last_sets
[i
], 0);
1547 reg_pending_sets_all
= 1;
1549 flush_pending_lists (insn
, 0);
1552 while (XEXP (link
, 1))
1553 link
= XEXP (link
, 1);
1554 XEXP (link
, 1) = REG_NOTES (insn
);
1555 REG_NOTES (insn
) = loop_notes
;
1558 /* After reload, it is possible for an instruction to have a REG_DEAD note
1559 for a register that actually dies a few instructions earlier. For
1560 example, this can happen with SECONDARY_MEMORY_NEEDED reloads.
1561 In this case, we must consider the insn to use the register mentioned
1562 in the REG_DEAD note. Otherwise, we may accidentally move this insn
1563 after another insn that sets the register, thus getting obviously invalid
1564 rtl. This confuses reorg which believes that REG_DEAD notes are still
1567 ??? We would get better code if we fixed reload to put the REG_DEAD
1568 notes in the right places, but that may not be worth the effort. */
1570 if (reload_completed
)
1574 for (note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
1575 if (REG_NOTE_KIND (note
) == REG_DEAD
)
1576 sched_analyze_2 (XEXP (note
, 0), insn
);
1579 EXECUTE_IF_SET_IN_REG_SET (reg_pending_sets
, 0, i
,
1581 reg_last_sets
[i
] = insn
;
1583 CLEAR_REG_SET (reg_pending_sets
);
1585 if (reg_pending_sets_all
)
1587 for (i
= 0; i
< maxreg
; i
++)
1588 reg_last_sets
[i
] = insn
;
1589 reg_pending_sets_all
= 0;
1592 /* Handle function calls and function returns created by the epilogue
1594 if (GET_CODE (insn
) == CALL_INSN
|| GET_CODE (insn
) == JUMP_INSN
)
1599 /* When scheduling instructions, we make sure calls don't lose their
1600 accompanying USE insns by depending them one on another in order.
1602 Also, we must do the same thing for returns created by the epilogue
1603 threading code. Note this code works only in this special case,
1604 because other passes make no guarantee that they will never emit
1605 an instruction between a USE and a RETURN. There is such a guarantee
1606 for USE instructions immediately before a call. */
1608 prev_dep_insn
= insn
;
1609 dep_insn
= PREV_INSN (insn
);
1610 while (GET_CODE (dep_insn
) == INSN
1611 && GET_CODE (PATTERN (dep_insn
)) == USE
1612 && GET_CODE (XEXP (PATTERN (dep_insn
), 0)) == REG
)
1614 SCHED_GROUP_P (prev_dep_insn
) = 1;
1616 /* Make a copy of all dependencies on dep_insn, and add to insn.
1617 This is so that all of the dependencies will apply to the
1620 for (link
= LOG_LINKS (dep_insn
); link
; link
= XEXP (link
, 1))
1621 add_dependence (insn
, XEXP (link
, 0), REG_NOTE_KIND (link
));
1623 prev_dep_insn
= dep_insn
;
1624 dep_insn
= PREV_INSN (dep_insn
);
1629 /* Analyze every insn between HEAD and TAIL inclusive, creating LOG_LINKS
1630 for every dependency. */
1633 sched_analyze (head
, tail
)
1637 register int n_insns
= 0;
1639 register int luid
= 0;
1642 for (insn
= head
; ; insn
= NEXT_INSN (insn
))
1644 INSN_LUID (insn
) = luid
++;
1646 if (GET_CODE (insn
) == INSN
|| GET_CODE (insn
) == JUMP_INSN
)
1648 sched_analyze_insn (PATTERN (insn
), insn
, loop_notes
);
1652 else if (GET_CODE (insn
) == CALL_INSN
)
1657 /* Any instruction using a hard register which may get clobbered
1658 by a call needs to be marked as dependent on this call.
1659 This prevents a use of a hard return reg from being moved
1660 past a void call (i.e. it does not explicitly set the hard
1663 /* If this call is followed by a NOTE_INSN_SETJMP, then assume that
1664 all registers, not just hard registers, may be clobbered by this
1667 /* Insn, being a CALL_INSN, magically depends on
1668 `last_function_call' already. */
1670 if (NEXT_INSN (insn
) && GET_CODE (NEXT_INSN (insn
)) == NOTE
1671 && NOTE_LINE_NUMBER (NEXT_INSN (insn
)) == NOTE_INSN_SETJMP
)
1673 int max_reg
= max_reg_num ();
1674 for (i
= 0; i
< max_reg
; i
++)
1676 for (u
= reg_last_uses
[i
]; u
; u
= XEXP (u
, 1))
1677 add_dependence (insn
, XEXP (u
, 0), REG_DEP_ANTI
);
1678 reg_last_uses
[i
] = 0;
1679 if (reg_last_sets
[i
])
1680 add_dependence (insn
, reg_last_sets
[i
], 0);
1682 reg_pending_sets_all
= 1;
1684 /* Add a pair of fake REG_NOTEs which we will later
1685 convert back into a NOTE_INSN_SETJMP note. See
1686 reemit_notes for why we use a pair of of NOTEs. */
1688 REG_NOTES (insn
) = gen_rtx_EXPR_LIST (REG_DEAD
,
1691 REG_NOTES (insn
) = gen_rtx_EXPR_LIST (REG_DEAD
,
1692 GEN_INT (NOTE_INSN_SETJMP
),
1697 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1698 if (call_used_regs
[i
] || global_regs
[i
])
1700 for (u
= reg_last_uses
[i
]; u
; u
= XEXP (u
, 1))
1701 add_dependence (insn
, XEXP (u
, 0), REG_DEP_ANTI
);
1702 reg_last_uses
[i
] = 0;
1703 if (reg_last_sets
[i
])
1704 add_dependence (insn
, reg_last_sets
[i
], REG_DEP_ANTI
);
1705 SET_REGNO_REG_SET (reg_pending_sets
, i
);
1709 /* For each insn which shouldn't cross a call, add a dependence
1710 between that insn and this call insn. */
1711 x
= LOG_LINKS (sched_before_next_call
);
1714 add_dependence (insn
, XEXP (x
, 0), REG_DEP_ANTI
);
1717 LOG_LINKS (sched_before_next_call
) = 0;
1719 sched_analyze_insn (PATTERN (insn
), insn
, loop_notes
);
1722 /* In the absence of interprocedural alias analysis, we must flush
1723 all pending reads and writes, and start new dependencies starting
1724 from here. But only flush writes for constant calls (which may
1725 be passed a pointer to something we haven't written yet). */
1726 flush_pending_lists (insn
, CONST_CALL_P (insn
));
1728 /* Depend this function call (actually, the user of this
1729 function call) on all hard register clobberage. */
1730 last_function_call
= insn
;
1734 /* See comments on reemit_notes as to why we do this. */
1735 else if (GET_CODE (insn
) == NOTE
1736 && (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
1737 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_END
1738 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_EH_REGION_BEG
1739 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_EH_REGION_END
1740 || (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_SETJMP
1741 && GET_CODE (PREV_INSN (insn
)) != CALL_INSN
)))
1743 loop_notes
= gen_rtx_EXPR_LIST (REG_DEAD
,
1744 GEN_INT (NOTE_BLOCK_NUMBER (insn
)),
1746 loop_notes
= gen_rtx_EXPR_LIST (REG_DEAD
,
1747 GEN_INT (NOTE_LINE_NUMBER (insn
)),
1749 CONST_CALL_P (loop_notes
) = CONST_CALL_P (insn
);
1759 /* Called when we see a set of a register. If death is true, then we are
1760 scanning backwards. Mark that register as unborn. If nobody says
1761 otherwise, that is how things will remain. If death is false, then we
1762 are scanning forwards. Mark that register as being born. */
1765 sched_note_set (b
, x
, death
)
1771 register rtx reg
= SET_DEST (x
);
1777 while (GET_CODE (reg
) == SUBREG
|| GET_CODE (reg
) == STRICT_LOW_PART
1778 || GET_CODE (reg
) == SIGN_EXTRACT
|| GET_CODE (reg
) == ZERO_EXTRACT
)
1780 /* Must treat modification of just one hardware register of a multi-reg
1781 value or just a byte field of a register exactly the same way that
1782 mark_set_1 in flow.c does, i.e. anything except a paradoxical subreg
1783 does not kill the entire register. */
1784 if (GET_CODE (reg
) != SUBREG
1785 || REG_SIZE (SUBREG_REG (reg
)) > REG_SIZE (reg
))
1788 reg
= SUBREG_REG (reg
);
1791 if (GET_CODE (reg
) != REG
)
1794 /* Global registers are always live, so the code below does not apply
1797 regno
= REGNO (reg
);
1798 if (regno
>= FIRST_PSEUDO_REGISTER
|| ! global_regs
[regno
])
1802 /* If we only set part of the register, then this set does not
1807 /* Try killing this register. */
1808 if (regno
< FIRST_PSEUDO_REGISTER
)
1810 int j
= HARD_REGNO_NREGS (regno
, GET_MODE (reg
));
1813 CLEAR_REGNO_REG_SET (bb_live_regs
, regno
+ j
);
1814 SET_REGNO_REG_SET (bb_dead_regs
, regno
+ j
);
1819 CLEAR_REGNO_REG_SET (bb_live_regs
, regno
);
1820 SET_REGNO_REG_SET (bb_dead_regs
, regno
);
1825 /* Make the register live again. */
1826 if (regno
< FIRST_PSEUDO_REGISTER
)
1828 int j
= HARD_REGNO_NREGS (regno
, GET_MODE (reg
));
1831 SET_REGNO_REG_SET (bb_live_regs
, regno
+ j
);
1832 CLEAR_REGNO_REG_SET (bb_dead_regs
, regno
+ j
);
1837 SET_REGNO_REG_SET (bb_live_regs
, regno
);
1838 CLEAR_REGNO_REG_SET (bb_dead_regs
, regno
);
1844 /* Macros and functions for keeping the priority queue sorted, and
1845 dealing with queueing and dequeueing of instructions. */
1847 #define SCHED_SORT(READY, NEW_READY, OLD_READY) \
1848 do { if ((NEW_READY) - (OLD_READY) == 1) \
1849 swap_sort (READY, NEW_READY); \
1850 else if ((NEW_READY) - (OLD_READY) > 1) \
1851 qsort (READY, NEW_READY, sizeof (rtx), rank_for_schedule); } \
1854 /* Returns a positive value if y is preferred; returns a negative value if
1855 x is preferred. Should never return 0, since that will make the sort
1859 rank_for_schedule (x
, y
)
1860 const GENERIC_PTR x
;
1861 const GENERIC_PTR y
;
1863 rtx tmp
= *(rtx
*)y
;
1864 rtx tmp2
= *(rtx
*)x
;
1866 int tmp_class
, tmp2_class
;
1869 /* Choose the instruction with the highest priority, if different. */
1870 if ((value
= INSN_PRIORITY (tmp
) - INSN_PRIORITY (tmp2
)))
1873 if (last_scheduled_insn
)
1875 /* Classify the instructions into three classes:
1876 1) Data dependent on last schedule insn.
1877 2) Anti/Output dependent on last scheduled insn.
1878 3) Independent of last scheduled insn, or has latency of one.
1879 Choose the insn from the highest numbered class if different. */
1880 link
= find_insn_list (tmp
, LOG_LINKS (last_scheduled_insn
));
1881 if (link
== 0 || insn_cost (tmp
, link
, last_scheduled_insn
) == 1)
1883 else if (REG_NOTE_KIND (link
) == 0) /* Data dependence. */
1888 link
= find_insn_list (tmp2
, LOG_LINKS (last_scheduled_insn
));
1889 if (link
== 0 || insn_cost (tmp2
, link
, last_scheduled_insn
) == 1)
1891 else if (REG_NOTE_KIND (link
) == 0) /* Data dependence. */
1896 if ((value
= tmp_class
- tmp2_class
))
1900 /* If insns are equally good, sort by INSN_LUID (original insn order),
1901 so that we make the sort stable. This minimizes instruction movement,
1902 thus minimizing sched's effect on debugging and cross-jumping. */
1903 return INSN_LUID (tmp
) - INSN_LUID (tmp2
);
1906 /* Resort the array A in which only element at index N may be out of order. */
1908 __inline
static void
1916 while (i
>= 0 && rank_for_schedule (a
+i
, &insn
) >= 0)
1924 static int max_priority
;
1926 /* Add INSN to the insn queue so that it fires at least N_CYCLES
1927 before the currently executing insn. */
1929 __inline
static void
1930 queue_insn (insn
, n_cycles
)
1934 int next_q
= NEXT_Q_AFTER (q_ptr
, n_cycles
);
1935 NEXT_INSN (insn
) = insn_queue
[next_q
];
1936 insn_queue
[next_q
] = insn
;
1940 /* Return nonzero if PAT is the pattern of an insn which makes a
1944 birthing_insn_p (pat
)
1949 if (reload_completed
== 1)
1952 if (GET_CODE (pat
) == SET
1953 && GET_CODE (SET_DEST (pat
)) == REG
)
1955 rtx dest
= SET_DEST (pat
);
1956 int i
= REGNO (dest
);
1958 /* It would be more accurate to use refers_to_regno_p or
1959 reg_mentioned_p to determine when the dest is not live before this
1962 if (REGNO_REG_SET_P (bb_live_regs
, i
))
1963 return (REG_N_SETS (i
) == 1);
1967 if (GET_CODE (pat
) == PARALLEL
)
1969 for (j
= 0; j
< XVECLEN (pat
, 0); j
++)
1970 if (birthing_insn_p (XVECEXP (pat
, 0, j
)))
1976 /* PREV is an insn that is ready to execute. Adjust its priority if that
1977 will help shorten register lifetimes. */
1979 __inline
static void
1980 adjust_priority (prev
)
1983 /* Trying to shorten register lives after reload has completed
1984 is useless and wrong. It gives inaccurate schedules. */
1985 if (reload_completed
== 0)
1990 /* ??? This code has no effect, because REG_DEAD notes are removed
1991 before we ever get here. */
1992 for (note
= REG_NOTES (prev
); note
; note
= XEXP (note
, 1))
1993 if (REG_NOTE_KIND (note
) == REG_DEAD
)
1996 /* Defer scheduling insns which kill registers, since that
1997 shortens register lives. Prefer scheduling insns which
1998 make registers live for the same reason. */
2002 INSN_PRIORITY (prev
) >>= 3;
2005 INSN_PRIORITY (prev
) >>= 2;
2009 INSN_PRIORITY (prev
) >>= 1;
2012 if (birthing_insn_p (PATTERN (prev
)))
2014 int max
= max_priority
;
2016 if (max
> INSN_PRIORITY (prev
))
2017 INSN_PRIORITY (prev
) = max
;
2021 #ifdef ADJUST_PRIORITY
2022 ADJUST_PRIORITY (prev
);
2027 /* INSN is the "currently executing insn". Launch each insn which was
2028 waiting on INSN (in the backwards dataflow sense). READY is a
2029 vector of insns which are ready to fire. N_READY is the number of
2030 elements in READY. CLOCK is the current virtual cycle. */
2033 schedule_insn (insn
, ready
, n_ready
, clock
)
2040 int new_ready
= n_ready
;
2042 if (MAX_BLOCKAGE
> 1)
2043 schedule_unit (insn_unit (insn
), insn
, clock
);
2045 if (LOG_LINKS (insn
) == 0)
2048 /* This is used by the function adjust_priority above. */
2050 max_priority
= MAX (INSN_PRIORITY (ready
[0]), INSN_PRIORITY (insn
));
2052 max_priority
= INSN_PRIORITY (insn
);
2054 for (link
= LOG_LINKS (insn
); link
!= 0; link
= XEXP (link
, 1))
2056 rtx prev
= XEXP (link
, 0);
2057 int cost
= insn_cost (prev
, link
, insn
);
2059 if ((INSN_REF_COUNT (prev
) -= 1) != 0)
2061 /* We satisfied one requirement to fire PREV. Record the earliest
2062 time when PREV can fire. No need to do this if the cost is 1,
2063 because PREV can fire no sooner than the next cycle. */
2065 INSN_TICK (prev
) = MAX (INSN_TICK (prev
), clock
+ cost
);
2069 /* We satisfied the last requirement to fire PREV. Ensure that all
2070 timing requirements are satisfied. */
2071 if (INSN_TICK (prev
) - clock
> cost
)
2072 cost
= INSN_TICK (prev
) - clock
;
2074 /* Adjust the priority of PREV and either put it on the ready
2075 list or queue it. */
2076 adjust_priority (prev
);
2078 ready
[new_ready
++] = prev
;
2080 queue_insn (prev
, cost
);
2087 /* Given N_READY insns in the ready list READY at time CLOCK, queue
2088 those that are blocked due to function unit hazards and rearrange
2089 the remaining ones to minimize subsequent function unit hazards. */
2092 schedule_select (ready
, n_ready
, clock
, file
)
2097 int pri
= INSN_PRIORITY (ready
[0]);
2098 int i
, j
, k
, q
, cost
, best_cost
, best_insn
= 0, new_ready
= n_ready
;
2101 /* Work down the ready list in groups of instructions with the same
2102 priority value. Queue insns in the group that are blocked and
2103 select among those that remain for the one with the largest
2104 potential hazard. */
2105 for (i
= 0; i
< n_ready
; i
= j
)
2108 for (j
= i
+ 1; j
< n_ready
; j
++)
2109 if ((pri
= INSN_PRIORITY (ready
[j
])) != opri
)
2112 /* Queue insns in the group that are blocked. */
2113 for (k
= i
, q
= 0; k
< j
; k
++)
2116 if ((cost
= actual_hazard (insn_unit (insn
), insn
, clock
, 0)) != 0)
2120 queue_insn (insn
, cost
);
2122 fprintf (file
, "\n;; blocking insn %d for %d cycles",
2123 INSN_UID (insn
), cost
);
2128 /* Check the next group if all insns were queued. */
2132 /* If more than one remains, select the first one with the largest
2133 potential hazard. */
2134 else if (j
- i
- q
> 1)
2137 for (k
= i
; k
< j
; k
++)
2139 if ((insn
= ready
[k
]) == 0)
2141 if ((cost
= potential_hazard (insn_unit (insn
), insn
, 0))
2149 /* We have found a suitable insn to schedule. */
2153 /* Move the best insn to be front of the ready list. */
2158 fprintf (file
, ", now");
2159 for (i
= 0; i
< n_ready
; i
++)
2161 fprintf (file
, " %d", INSN_UID (ready
[i
]));
2162 fprintf (file
, "\n;; insn %d has a greater potential hazard",
2163 INSN_UID (ready
[best_insn
]));
2165 for (i
= best_insn
; i
> 0; i
--)
2168 ready
[i
-1] = ready
[i
];
2173 /* Compact the ready list. */
2174 if (new_ready
< n_ready
)
2175 for (i
= j
= 0; i
< n_ready
; i
++)
2177 ready
[j
++] = ready
[i
];
2182 /* Add a REG_DEAD note for REG to INSN, reusing a REG_DEAD note from the
2186 create_reg_dead_note (reg
, insn
)
2191 /* The number of registers killed after scheduling must be the same as the
2192 number of registers killed before scheduling. The number of REG_DEAD
2193 notes may not be conserved, i.e. two SImode hard register REG_DEAD notes
2194 might become one DImode hard register REG_DEAD note, but the number of
2195 registers killed will be conserved.
2197 We carefully remove REG_DEAD notes from the dead_notes list, so that
2198 there will be none left at the end. If we run out early, then there
2199 is a bug somewhere in flow, combine and/or sched. */
2201 if (dead_notes
== 0)
2206 link
= rtx_alloc (EXPR_LIST
);
2207 PUT_REG_NOTE_KIND (link
, REG_DEAD
);
2212 /* Number of regs killed by REG. */
2213 int regs_killed
= (REGNO (reg
) >= FIRST_PSEUDO_REGISTER
? 1
2214 : HARD_REGNO_NREGS (REGNO (reg
), GET_MODE (reg
)));
2215 /* Number of regs killed by REG_DEAD notes taken off the list. */
2219 reg_note_regs
= (REGNO (XEXP (link
, 0)) >= FIRST_PSEUDO_REGISTER
? 1
2220 : HARD_REGNO_NREGS (REGNO (XEXP (link
, 0)),
2221 GET_MODE (XEXP (link
, 0))));
2222 while (reg_note_regs
< regs_killed
)
2224 /* LINK might be zero if we killed more registers after scheduling
2225 than before, and the last hard register we kill is actually
2226 multiple hard regs. */
2227 if (link
== NULL_RTX
)
2230 link
= XEXP (link
, 1);
2231 reg_note_regs
+= (REGNO (XEXP (link
, 0)) >= FIRST_PSEUDO_REGISTER
? 1
2232 : HARD_REGNO_NREGS (REGNO (XEXP (link
, 0)),
2233 GET_MODE (XEXP (link
, 0))));
2235 dead_notes
= XEXP (link
, 1);
2237 /* If we took too many regs kills off, put the extra ones back. */
2238 while (reg_note_regs
> regs_killed
)
2240 rtx temp_reg
, temp_link
;
2242 temp_reg
= gen_rtx_REG (word_mode
, 0);
2243 temp_link
= rtx_alloc (EXPR_LIST
);
2244 PUT_REG_NOTE_KIND (temp_link
, REG_DEAD
);
2245 XEXP (temp_link
, 0) = temp_reg
;
2246 XEXP (temp_link
, 1) = dead_notes
;
2247 dead_notes
= temp_link
;
2252 XEXP (link
, 0) = reg
;
2253 XEXP (link
, 1) = REG_NOTES (insn
);
2254 REG_NOTES (insn
) = link
;
2257 /* Subroutine on attach_deaths_insn--handles the recursive search
2258 through INSN. If SET_P is true, then x is being modified by the insn. */
2261 attach_deaths (x
, insn
, set_p
)
2268 register enum rtx_code code
;
2274 code
= GET_CODE (x
);
2286 /* Get rid of the easy cases first. */
2291 /* If the register dies in this insn, queue that note, and mark
2292 this register as needing to die. */
2293 /* This code is very similar to mark_used_1 (if set_p is false)
2294 and mark_set_1 (if set_p is true) in flow.c. */
2304 all_needed
= some_needed
= REGNO_REG_SET_P (old_live_regs
, regno
);
2305 if (regno
< FIRST_PSEUDO_REGISTER
)
2309 n
= HARD_REGNO_NREGS (regno
, GET_MODE (x
));
2312 int needed
= (REGNO_REG_SET_P (old_live_regs
, regno
+ n
));
2313 some_needed
|= needed
;
2314 all_needed
&= needed
;
2318 /* If it wasn't live before we started, then add a REG_DEAD note.
2319 We must check the previous lifetime info not the current info,
2320 because we may have to execute this code several times, e.g.
2321 once for a clobber (which doesn't add a note) and later
2322 for a use (which does add a note).
2324 Always make the register live. We must do this even if it was
2325 live before, because this may be an insn which sets and uses
2326 the same register, in which case the register has already been
2327 killed, so we must make it live again.
2329 Global registers are always live, and should never have a REG_DEAD
2330 note added for them, so none of the code below applies to them. */
2332 if (regno
>= FIRST_PSEUDO_REGISTER
|| ! global_regs
[regno
])
2334 /* Never add REG_DEAD notes for the FRAME_POINTER_REGNUM or the
2335 STACK_POINTER_REGNUM, since these are always considered to be
2336 live. Similarly for ARG_POINTER_REGNUM if it is fixed. */
2337 if (regno
!= FRAME_POINTER_REGNUM
2338 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
2339 && ! (regno
== HARD_FRAME_POINTER_REGNUM
)
2341 #if ARG_POINTER_REGNUM != FRAME_POINTER_REGNUM
2342 && ! (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
2344 && regno
!= STACK_POINTER_REGNUM
)
2346 /* ??? It is perhaps a dead_or_set_p bug that it does
2347 not check for REG_UNUSED notes itself. This is necessary
2348 for the case where the SET_DEST is a subreg of regno, as
2349 dead_or_set_p handles subregs specially. */
2350 if (! all_needed
&& ! dead_or_set_p (insn
, x
)
2351 && ! find_reg_note (insn
, REG_UNUSED
, x
))
2353 /* Check for the case where the register dying partially
2354 overlaps the register set by this insn. */
2355 if (regno
< FIRST_PSEUDO_REGISTER
2356 && HARD_REGNO_NREGS (regno
, GET_MODE (x
)) > 1)
2358 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (x
));
2360 some_needed
|= dead_or_set_regno_p (insn
, regno
+ n
);
2363 /* If none of the words in X is needed, make a REG_DEAD
2364 note. Otherwise, we must make partial REG_DEAD
2367 create_reg_dead_note (x
, insn
);
2372 /* Don't make a REG_DEAD note for a part of a
2373 register that is set in the insn. */
2374 for (i
= HARD_REGNO_NREGS (regno
, GET_MODE (x
)) - 1;
2376 if (! REGNO_REG_SET_P (old_live_regs
, regno
+ i
)
2377 && ! dead_or_set_regno_p (insn
, regno
+ i
))
2378 create_reg_dead_note (gen_rtx_REG (reg_raw_mode
[regno
+ i
],
2385 if (regno
< FIRST_PSEUDO_REGISTER
)
2387 int j
= HARD_REGNO_NREGS (regno
, GET_MODE (x
));
2390 CLEAR_REGNO_REG_SET (bb_dead_regs
, regno
+ j
);
2391 SET_REGNO_REG_SET (bb_live_regs
, regno
+ j
);
2396 CLEAR_REGNO_REG_SET (bb_dead_regs
, regno
);
2397 SET_REGNO_REG_SET (bb_live_regs
, regno
);
2404 /* Handle tail-recursive case. */
2405 attach_deaths (XEXP (x
, 0), insn
, 0);
2409 case STRICT_LOW_PART
:
2410 /* These two cases preserve the value of SET_P, so handle them
2412 attach_deaths (XEXP (x
, 0), insn
, set_p
);
2417 /* This case preserves the value of SET_P for the first operand, but
2418 clears it for the other two. */
2419 attach_deaths (XEXP (x
, 0), insn
, set_p
);
2420 attach_deaths (XEXP (x
, 1), insn
, 0);
2421 attach_deaths (XEXP (x
, 2), insn
, 0);
2425 /* Other cases: walk the insn. */
2426 fmt
= GET_RTX_FORMAT (code
);
2427 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
2430 attach_deaths (XEXP (x
, i
), insn
, 0);
2431 else if (fmt
[i
] == 'E')
2432 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
2433 attach_deaths (XVECEXP (x
, i
, j
), insn
, 0);
2438 /* After INSN has executed, add register death notes for each register
2439 that is dead after INSN. */
2442 attach_deaths_insn (insn
)
2445 rtx x
= PATTERN (insn
);
2446 register RTX_CODE code
= GET_CODE (x
);
2451 attach_deaths (SET_SRC (x
), insn
, 0);
2453 /* A register might die here even if it is the destination, e.g.
2454 it is the target of a volatile read and is otherwise unused.
2455 Hence we must always call attach_deaths for the SET_DEST. */
2456 attach_deaths (SET_DEST (x
), insn
, 1);
2458 else if (code
== PARALLEL
)
2461 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
2463 code
= GET_CODE (XVECEXP (x
, 0, i
));
2466 attach_deaths (SET_SRC (XVECEXP (x
, 0, i
)), insn
, 0);
2468 attach_deaths (SET_DEST (XVECEXP (x
, 0, i
)), insn
, 1);
2470 /* Flow does not add REG_DEAD notes to registers that die in
2471 clobbers, so we can't either. */
2472 else if (code
!= CLOBBER
)
2473 attach_deaths (XVECEXP (x
, 0, i
), insn
, 0);
2476 /* If this is a CLOBBER, only add REG_DEAD notes to registers inside a
2477 MEM being clobbered, just like flow. */
2478 else if (code
== CLOBBER
&& GET_CODE (XEXP (x
, 0)) == MEM
)
2479 attach_deaths (XEXP (XEXP (x
, 0), 0), insn
, 0);
2480 /* Otherwise don't add a death note to things being clobbered. */
2481 else if (code
!= CLOBBER
)
2482 attach_deaths (x
, insn
, 0);
2484 /* Make death notes for things used in the called function. */
2485 if (GET_CODE (insn
) == CALL_INSN
)
2486 for (link
= CALL_INSN_FUNCTION_USAGE (insn
); link
; link
= XEXP (link
, 1))
2487 attach_deaths (XEXP (XEXP (link
, 0), 0), insn
,
2488 GET_CODE (XEXP (link
, 0)) == CLOBBER
);
2491 /* Delete notes beginning with INSN and maybe put them in the chain
2492 of notes ended by NOTE_LIST.
2493 Returns the insn following the notes. */
2496 unlink_notes (insn
, tail
)
2499 rtx prev
= PREV_INSN (insn
);
2501 while (insn
!= tail
&& GET_CODE (insn
) == NOTE
)
2503 rtx next
= NEXT_INSN (insn
);
2504 /* Delete the note from its current position. */
2506 NEXT_INSN (prev
) = next
;
2508 PREV_INSN (next
) = prev
;
2510 if (write_symbols
!= NO_DEBUG
&& NOTE_LINE_NUMBER (insn
) > 0)
2511 /* Record line-number notes so they can be reused. */
2512 LINE_NOTE (insn
) = insn
;
2514 /* Don't save away NOTE_INSN_SETJMPs, because they must remain
2515 immediately after the call they follow. We use a fake
2516 (REG_DEAD (const_int -1)) note to remember them.
2517 Likewise with NOTE_INSN_{LOOP,EHREGION}_{BEG, END}. */
2518 else if (NOTE_LINE_NUMBER (insn
) != NOTE_INSN_SETJMP
2519 && NOTE_LINE_NUMBER (insn
) != NOTE_INSN_LOOP_BEG
2520 && NOTE_LINE_NUMBER (insn
) != NOTE_INSN_LOOP_END
2521 && NOTE_LINE_NUMBER (insn
) != NOTE_INSN_EH_REGION_BEG
2522 && NOTE_LINE_NUMBER (insn
) != NOTE_INSN_EH_REGION_END
)
2524 /* Insert the note at the end of the notes list. */
2525 PREV_INSN (insn
) = note_list
;
2527 NEXT_INSN (note_list
) = insn
;
2536 /* Constructor for `sometimes' data structure. */
2539 new_sometimes_live (regs_sometimes_live
, regno
, sometimes_max
)
2540 struct sometimes
*regs_sometimes_live
;
2544 register struct sometimes
*p
;
2546 /* There should never be a register greater than max_regno here. If there
2547 is, it means that a define_split has created a new pseudo reg. This
2548 is not allowed, since there will not be flow info available for any
2549 new register, so catch the error here. */
2550 if (regno
>= max_regno
)
2553 p
= ®s_sometimes_live
[sometimes_max
];
2556 p
->calls_crossed
= 0;
2558 return sometimes_max
;
2561 /* Count lengths of all regs we are currently tracking,
2562 and find new registers no longer live. */
2565 finish_sometimes_live (regs_sometimes_live
, sometimes_max
)
2566 struct sometimes
*regs_sometimes_live
;
2571 for (i
= 0; i
< sometimes_max
; i
++)
2573 register struct sometimes
*p
= ®s_sometimes_live
[i
];
2574 int regno
= p
->regno
;
2576 sched_reg_live_length
[regno
] += p
->live_length
;
2577 sched_reg_n_calls_crossed
[regno
] += p
->calls_crossed
;
2581 /* Search INSN for fake REG_DEAD note pairs for NOTE_INSN_SETJMP,
2582 NOTE_INSN_{LOOP,EHREGION}_{BEG,END}; and convert them back into
2583 NOTEs. The REG_DEAD note following first one is contains the saved
2584 value for NOTE_BLOCK_NUMBER which is useful for
2585 NOTE_INSN_EH_REGION_{BEG,END} NOTEs. LAST is the last instruction
2586 output by the instruction scheduler. Return the new value of LAST. */
2589 reemit_notes (insn
, last
)
2595 for (note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
2597 if (REG_NOTE_KIND (note
) == REG_DEAD
2598 && GET_CODE (XEXP (note
, 0)) == CONST_INT
)
2600 if (INTVAL (XEXP (note
, 0)) == NOTE_INSN_SETJMP
)
2602 CONST_CALL_P (emit_note_after (INTVAL (XEXP (note
, 0)), insn
))
2603 = CONST_CALL_P (note
);
2604 remove_note (insn
, note
);
2605 note
= XEXP (note
, 1);
2609 last
= emit_note_before (INTVAL (XEXP (note
, 0)), last
);
2610 remove_note (insn
, note
);
2611 note
= XEXP (note
, 1);
2612 NOTE_BLOCK_NUMBER (last
) = INTVAL (XEXP (note
, 0));
2614 remove_note (insn
, note
);
2620 /* Use modified list scheduling to rearrange insns in basic block
2621 B. FILE, if nonzero, is where we dump interesting output about
2625 schedule_block (b
, file
)
2631 int i
, j
, n_ready
= 0, new_ready
, n_insns
;
2632 int sched_n_insns
= 0;
2634 #define NEED_NOTHING 0
2639 /* HEAD and TAIL delimit the region being scheduled. */
2640 rtx head
= basic_block_head
[b
];
2641 rtx tail
= basic_block_end
[b
];
2642 /* PREV_HEAD and NEXT_TAIL are the boundaries of the insns
2643 being scheduled. When the insns have been ordered,
2644 these insns delimit where the new insns are to be
2645 spliced back into the insn chain. */
2649 /* Keep life information accurate. */
2650 register struct sometimes
*regs_sometimes_live
;
2654 fprintf (file
, ";;\t -- basic block number %d from %d to %d --\n",
2655 b
, INSN_UID (basic_block_head
[b
]), INSN_UID (basic_block_end
[b
]));
2658 reg_last_uses
= (rtx
*) alloca (i
* sizeof (rtx
));
2659 bzero ((char *) reg_last_uses
, i
* sizeof (rtx
));
2660 reg_last_sets
= (rtx
*) alloca (i
* sizeof (rtx
));
2661 bzero ((char *) reg_last_sets
, i
* sizeof (rtx
));
2662 reg_pending_sets
= ALLOCA_REG_SET ();
2663 CLEAR_REG_SET (reg_pending_sets
);
2664 reg_pending_sets_all
= 0;
2668 /* We used to have code to avoid getting parameters moved from hard
2669 argument registers into pseudos.
2671 However, it was removed when it proved to be of marginal benefit and
2672 caused problems because of different notions of what the "head" insn
2675 /* Remove certain insns at the beginning from scheduling,
2676 by advancing HEAD. */
2678 /* At the start of a function, before reload has run, don't delay getting
2679 parameters from hard registers into pseudo registers. */
2680 if (reload_completed
== 0 && b
== 0)
2683 && GET_CODE (head
) == NOTE
2684 && NOTE_LINE_NUMBER (head
) != NOTE_INSN_FUNCTION_BEG
)
2685 head
= NEXT_INSN (head
);
2687 && GET_CODE (head
) == INSN
2688 && GET_CODE (PATTERN (head
)) == SET
)
2690 rtx src
= SET_SRC (PATTERN (head
));
2691 while (GET_CODE (src
) == SUBREG
2692 || GET_CODE (src
) == SIGN_EXTEND
2693 || GET_CODE (src
) == ZERO_EXTEND
2694 || GET_CODE (src
) == SIGN_EXTRACT
2695 || GET_CODE (src
) == ZERO_EXTRACT
)
2696 src
= XEXP (src
, 0);
2697 if (GET_CODE (src
) != REG
2698 || REGNO (src
) >= FIRST_PSEUDO_REGISTER
)
2700 /* Keep this insn from ever being scheduled. */
2701 INSN_REF_COUNT (head
) = 1;
2702 head
= NEXT_INSN (head
);
2707 /* Don't include any notes or labels at the beginning of the
2708 basic block, or notes at the ends of basic blocks. */
2709 while (head
!= tail
)
2711 if (GET_CODE (head
) == NOTE
)
2712 head
= NEXT_INSN (head
);
2713 else if (GET_CODE (tail
) == NOTE
)
2714 tail
= PREV_INSN (tail
);
2715 else if (GET_CODE (head
) == CODE_LABEL
)
2716 head
= NEXT_INSN (head
);
2719 /* If the only insn left is a NOTE or a CODE_LABEL, then there is no need
2720 to schedule this block. */
2722 && (GET_CODE (head
) == NOTE
|| GET_CODE (head
) == CODE_LABEL
))
2726 /* This short-cut doesn't work. It does not count call insns crossed by
2727 registers in reg_sometimes_live. It does not mark these registers as
2728 dead if they die in this block. It does not mark these registers live
2729 (or create new reg_sometimes_live entries if necessary) if they are born
2732 The easy solution is to just always schedule a block. This block only
2733 has one insn, so this won't slow down this pass by much. */
2739 /* Now HEAD through TAIL are the insns actually to be rearranged;
2740 Let PREV_HEAD and NEXT_TAIL enclose them. */
2741 prev_head
= PREV_INSN (head
);
2742 next_tail
= NEXT_INSN (tail
);
2744 /* Initialize basic block data structures. */
2746 pending_read_insns
= 0;
2747 pending_read_mems
= 0;
2748 pending_write_insns
= 0;
2749 pending_write_mems
= 0;
2750 pending_lists_length
= 0;
2751 last_pending_memory_flush
= 0;
2752 last_function_call
= 0;
2753 last_scheduled_insn
= 0;
2755 LOG_LINKS (sched_before_next_call
) = 0;
2757 n_insns
= sched_analyze (head
, tail
);
2760 free_pending_lists ();
2764 /* Allocate vector to hold insns to be rearranged (except those
2765 insns which are controlled by an insn with SCHED_GROUP_P set).
2766 All these insns are included between ORIG_HEAD and ORIG_TAIL,
2767 as those variables ultimately are set up. */
2768 ready
= (rtx
*) alloca ((n_insns
+1) * sizeof (rtx
));
2770 /* TAIL is now the last of the insns to be rearranged.
2771 Put those insns into the READY vector. */
2774 /* For all branches, calls, uses, and cc0 setters, force them to remain
2775 in order at the end of the block by adding dependencies and giving
2776 the last a high priority. There may be notes present, and prev_head
2779 Branches must obviously remain at the end. Calls should remain at the
2780 end since moving them results in worse register allocation. Uses remain
2781 at the end to ensure proper register allocation. cc0 setters remaim
2782 at the end because they can't be moved away from their cc0 user. */
2784 while (GET_CODE (insn
) == CALL_INSN
|| GET_CODE (insn
) == JUMP_INSN
2785 || (GET_CODE (insn
) == INSN
2786 && (GET_CODE (PATTERN (insn
)) == USE
2788 || sets_cc0_p (PATTERN (insn
))
2791 || GET_CODE (insn
) == NOTE
)
2793 if (GET_CODE (insn
) != NOTE
)
2798 ready
[n_ready
++] = insn
;
2799 INSN_PRIORITY (insn
) = TAIL_PRIORITY
- i
;
2800 INSN_REF_COUNT (insn
) = 0;
2802 else if (! find_insn_list (insn
, LOG_LINKS (last
)))
2804 add_dependence (last
, insn
, REG_DEP_ANTI
);
2805 INSN_REF_COUNT (insn
)++;
2809 /* Skip over insns that are part of a group. */
2810 while (SCHED_GROUP_P (insn
))
2812 insn
= prev_nonnote_insn (insn
);
2817 insn
= PREV_INSN (insn
);
2818 /* Don't overrun the bounds of the basic block. */
2819 if (insn
== prev_head
)
2823 /* Assign priorities to instructions. Also check whether they
2824 are in priority order already. If so then I will be nonnegative.
2825 We use this shortcut only before reloading. */
2827 i
= reload_completed
? DONE_PRIORITY
: MAX_PRIORITY
;
2830 for (; insn
!= prev_head
; insn
= PREV_INSN (insn
))
2832 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i')
2835 if (INSN_REF_COUNT (insn
) == 0)
2838 ready
[n_ready
++] = insn
;
2841 /* Make this dependent on the last of the instructions
2842 that must remain in order at the end of the block. */
2843 add_dependence (last
, insn
, REG_DEP_ANTI
);
2844 INSN_REF_COUNT (insn
) = 1;
2847 if (SCHED_GROUP_P (insn
))
2849 while (SCHED_GROUP_P (insn
))
2851 insn
= prev_nonnote_insn (insn
);
2859 if (INSN_PRIORITY (insn
) < i
)
2860 i
= INSN_PRIORITY (insn
);
2861 else if (INSN_PRIORITY (insn
) > i
)
2868 /* This short-cut doesn't work. It does not count call insns crossed by
2869 registers in reg_sometimes_live. It does not mark these registers as
2870 dead if they die in this block. It does not mark these registers live
2871 (or create new reg_sometimes_live entries if necessary) if they are born
2874 The easy solution is to just always schedule a block. These blocks tend
2875 to be very short, so this doesn't slow down this pass by much. */
2877 /* If existing order is good, don't bother to reorder. */
2878 if (i
!= DONE_PRIORITY
)
2881 fprintf (file
, ";; already scheduled\n");
2883 if (reload_completed
== 0)
2885 for (i
= 0; i
< sometimes_max
; i
++)
2886 regs_sometimes_live
[i
].live_length
+= n_insns
;
2888 finish_sometimes_live (regs_sometimes_live
, sometimes_max
);
2890 free_pending_lists ();
2895 /* Scan all the insns to be scheduled, removing NOTE insns
2896 and register death notes.
2897 Line number NOTE insns end up in NOTE_LIST.
2898 Register death notes end up in DEAD_NOTES.
2900 Recreate the register life information for the end of this basic
2903 if (reload_completed
== 0)
2905 COPY_REG_SET (bb_live_regs
, basic_block_live_at_start
[b
]);
2906 CLEAR_REG_SET (bb_dead_regs
);
2910 /* This is the first block in the function. There may be insns
2911 before head that we can't schedule. We still need to examine
2912 them though for accurate register lifetime analysis. */
2914 /* We don't want to remove any REG_DEAD notes as the code below
2917 for (insn
= basic_block_head
[b
]; insn
!= head
;
2918 insn
= NEXT_INSN (insn
))
2919 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i')
2921 /* See if the register gets born here. */
2922 /* We must check for registers being born before we check for
2923 registers dying. It is possible for a register to be born
2924 and die in the same insn, e.g. reading from a volatile
2925 memory location into an otherwise unused register. Such
2926 a register must be marked as dead after this insn. */
2927 if (GET_CODE (PATTERN (insn
)) == SET
2928 || GET_CODE (PATTERN (insn
)) == CLOBBER
)
2929 sched_note_set (b
, PATTERN (insn
), 0);
2930 else if (GET_CODE (PATTERN (insn
)) == PARALLEL
)
2933 for (j
= XVECLEN (PATTERN (insn
), 0) - 1; j
>= 0; j
--)
2934 if (GET_CODE (XVECEXP (PATTERN (insn
), 0, j
)) == SET
2935 || GET_CODE (XVECEXP (PATTERN (insn
), 0, j
)) == CLOBBER
)
2936 sched_note_set (b
, XVECEXP (PATTERN (insn
), 0, j
), 0);
2938 /* ??? This code is obsolete and should be deleted. It
2939 is harmless though, so we will leave it in for now. */
2940 for (j
= XVECLEN (PATTERN (insn
), 0) - 1; j
>= 0; j
--)
2941 if (GET_CODE (XVECEXP (PATTERN (insn
), 0, j
)) == USE
)
2942 sched_note_set (b
, XVECEXP (PATTERN (insn
), 0, j
), 0);
2945 /* Each call clobbers (makes live) all call-clobbered regs
2946 that are not global or fixed. Note that the function-value
2947 reg is a call_clobbered reg. */
2949 if (GET_CODE (insn
) == CALL_INSN
)
2952 for (j
= 0; j
< FIRST_PSEUDO_REGISTER
; j
++)
2953 if (call_used_regs
[j
] && ! global_regs
[j
]
2956 SET_REGNO_REG_SET (bb_live_regs
, j
);
2957 CLEAR_REGNO_REG_SET (bb_dead_regs
, j
);
2961 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2963 if ((REG_NOTE_KIND (link
) == REG_DEAD
2964 || REG_NOTE_KIND (link
) == REG_UNUSED
)
2965 /* Verify that the REG_NOTE has a valid value. */
2966 && GET_CODE (XEXP (link
, 0)) == REG
)
2968 register int regno
= REGNO (XEXP (link
, 0));
2970 if (regno
< FIRST_PSEUDO_REGISTER
)
2972 int j
= HARD_REGNO_NREGS (regno
,
2973 GET_MODE (XEXP (link
, 0)));
2976 CLEAR_REGNO_REG_SET (bb_live_regs
, regno
+ j
);
2977 SET_REGNO_REG_SET (bb_dead_regs
, regno
+ j
);
2982 CLEAR_REGNO_REG_SET (bb_live_regs
, regno
);
2983 SET_REGNO_REG_SET (bb_dead_regs
, regno
);
2991 /* If debugging information is being produced, keep track of the line
2992 number notes for each insn. */
2993 if (write_symbols
!= NO_DEBUG
)
2995 /* We must use the true line number for the first insn in the block
2996 that was computed and saved at the start of this pass. We can't
2997 use the current line number, because scheduling of the previous
2998 block may have changed the current line number. */
2999 rtx line
= line_note_head
[b
];
3001 for (insn
= basic_block_head
[b
];
3003 insn
= NEXT_INSN (insn
))
3004 if (GET_CODE (insn
) == NOTE
&& NOTE_LINE_NUMBER (insn
) > 0)
3007 LINE_NOTE (insn
) = line
;
3010 for (insn
= head
; insn
!= next_tail
; insn
= NEXT_INSN (insn
))
3012 rtx prev
, next
, link
;
3014 /* Farm out notes. This is needed to keep the debugger from
3015 getting completely deranged. */
3016 if (GET_CODE (insn
) == NOTE
)
3019 insn
= unlink_notes (insn
, next_tail
);
3024 if (insn
== next_tail
)
3028 if (reload_completed
== 0
3029 && GET_RTX_CLASS (GET_CODE (insn
)) == 'i')
3031 /* See if the register gets born here. */
3032 /* We must check for registers being born before we check for
3033 registers dying. It is possible for a register to be born and
3034 die in the same insn, e.g. reading from a volatile memory
3035 location into an otherwise unused register. Such a register
3036 must be marked as dead after this insn. */
3037 if (GET_CODE (PATTERN (insn
)) == SET
3038 || GET_CODE (PATTERN (insn
)) == CLOBBER
)
3039 sched_note_set (b
, PATTERN (insn
), 0);
3040 else if (GET_CODE (PATTERN (insn
)) == PARALLEL
)
3043 for (j
= XVECLEN (PATTERN (insn
), 0) - 1; j
>= 0; j
--)
3044 if (GET_CODE (XVECEXP (PATTERN (insn
), 0, j
)) == SET
3045 || GET_CODE (XVECEXP (PATTERN (insn
), 0, j
)) == CLOBBER
)
3046 sched_note_set (b
, XVECEXP (PATTERN (insn
), 0, j
), 0);
3048 /* ??? This code is obsolete and should be deleted. It
3049 is harmless though, so we will leave it in for now. */
3050 for (j
= XVECLEN (PATTERN (insn
), 0) - 1; j
>= 0; j
--)
3051 if (GET_CODE (XVECEXP (PATTERN (insn
), 0, j
)) == USE
)
3052 sched_note_set (b
, XVECEXP (PATTERN (insn
), 0, j
), 0);
3055 /* Each call clobbers (makes live) all call-clobbered regs that are
3056 not global or fixed. Note that the function-value reg is a
3057 call_clobbered reg. */
3059 if (GET_CODE (insn
) == CALL_INSN
)
3062 for (j
= 0; j
< FIRST_PSEUDO_REGISTER
; j
++)
3063 if (call_used_regs
[j
] && ! global_regs
[j
]
3066 SET_REGNO_REG_SET (bb_live_regs
, j
);
3067 CLEAR_REGNO_REG_SET (bb_dead_regs
, j
);
3071 /* Need to know what registers this insn kills. */
3072 for (prev
= 0, link
= REG_NOTES (insn
); link
; link
= next
)
3074 next
= XEXP (link
, 1);
3075 if ((REG_NOTE_KIND (link
) == REG_DEAD
3076 || REG_NOTE_KIND (link
) == REG_UNUSED
)
3077 /* Verify that the REG_NOTE has a valid value. */
3078 && GET_CODE (XEXP (link
, 0)) == REG
)
3080 register int regno
= REGNO (XEXP (link
, 0));
3082 /* Only unlink REG_DEAD notes; leave REG_UNUSED notes
3084 if (REG_NOTE_KIND (link
) == REG_DEAD
)
3087 XEXP (prev
, 1) = next
;
3089 REG_NOTES (insn
) = next
;
3090 XEXP (link
, 1) = dead_notes
;
3096 if (regno
< FIRST_PSEUDO_REGISTER
)
3098 int j
= HARD_REGNO_NREGS (regno
,
3099 GET_MODE (XEXP (link
, 0)));
3102 CLEAR_REGNO_REG_SET (bb_live_regs
, regno
+ j
);
3103 SET_REGNO_REG_SET (bb_dead_regs
, regno
+ j
);
3108 CLEAR_REGNO_REG_SET (bb_live_regs
, regno
);
3109 SET_REGNO_REG_SET (bb_dead_regs
, regno
);
3118 if (reload_completed
== 0)
3120 /* Keep track of register lives. */
3121 old_live_regs
= ALLOCA_REG_SET ();
3123 = (struct sometimes
*) alloca (max_regno
* sizeof (struct sometimes
));
3126 /* Start with registers live at end. */
3127 COPY_REG_SET (old_live_regs
, bb_live_regs
);
3128 EXECUTE_IF_SET_IN_REG_SET (bb_live_regs
, 0, j
,
3131 = new_sometimes_live (regs_sometimes_live
,
3136 SCHED_SORT (ready
, n_ready
, 1);
3140 fprintf (file
, ";; ready list initially:\n;; ");
3141 for (i
= 0; i
< n_ready
; i
++)
3142 fprintf (file
, "%d ", INSN_UID (ready
[i
]));
3143 fprintf (file
, "\n\n");
3145 for (insn
= head
; insn
!= next_tail
; insn
= NEXT_INSN (insn
))
3146 if (INSN_PRIORITY (insn
) > 0)
3147 fprintf (file
, ";; insn[%4d]: priority = %4d, ref_count = %4d\n",
3148 INSN_UID (insn
), INSN_PRIORITY (insn
),
3149 INSN_REF_COUNT (insn
));
3152 /* Now HEAD and TAIL are going to become disconnected
3153 entirely from the insn chain. */
3156 /* Q_SIZE will always be zero here. */
3157 q_ptr
= 0; clock
= 0;
3158 bzero ((char *) insn_queue
, sizeof (insn_queue
));
3160 /* Now, perform list scheduling. */
3162 /* Where we start inserting insns is after TAIL. */
3165 new_needs
= (NEXT_INSN (prev_head
) == basic_block_head
[b
]
3166 ? NEED_HEAD
: NEED_NOTHING
);
3167 if (PREV_INSN (next_tail
) == basic_block_end
[b
])
3168 new_needs
|= NEED_TAIL
;
3170 new_ready
= n_ready
;
3171 while (sched_n_insns
< n_insns
)
3173 q_ptr
= NEXT_Q (q_ptr
); clock
++;
3175 /* Add all pending insns that can be scheduled without stalls to the
3177 for (insn
= insn_queue
[q_ptr
]; insn
; insn
= NEXT_INSN (insn
))
3180 fprintf (file
, ";; launching %d before %d with no stalls at T-%d\n",
3181 INSN_UID (insn
), INSN_UID (last
), clock
);
3182 ready
[new_ready
++] = insn
;
3185 insn_queue
[q_ptr
] = 0;
3187 /* If there are no ready insns, stall until one is ready and add all
3188 of the pending insns at that point to the ready list. */
3191 register int stalls
;
3193 for (stalls
= 1; stalls
< INSN_QUEUE_SIZE
; stalls
++)
3194 if ((insn
= insn_queue
[NEXT_Q_AFTER (q_ptr
, stalls
)]))
3196 for (; insn
; insn
= NEXT_INSN (insn
))
3199 fprintf (file
, ";; launching %d before %d with %d stalls at T-%d\n",
3200 INSN_UID (insn
), INSN_UID (last
), stalls
, clock
);
3201 ready
[new_ready
++] = insn
;
3204 insn_queue
[NEXT_Q_AFTER (q_ptr
, stalls
)] = 0;
3208 q_ptr
= NEXT_Q_AFTER (q_ptr
, stalls
); clock
+= stalls
;
3211 /* There should be some instructions waiting to fire. */
3217 fprintf (file
, ";; ready list at T-%d:", clock
);
3218 for (i
= 0; i
< new_ready
; i
++)
3219 fprintf (file
, " %d (%x)",
3220 INSN_UID (ready
[i
]), INSN_PRIORITY (ready
[i
]));
3223 /* Sort the ready list and choose the best insn to schedule. Select
3224 which insn should issue in this cycle and queue those that are
3225 blocked by function unit hazards.
3227 N_READY holds the number of items that were scheduled the last time,
3228 minus the one instruction scheduled on the last loop iteration; it
3229 is not modified for any other reason in this loop. */
3231 SCHED_SORT (ready
, new_ready
, n_ready
);
3232 if (MAX_BLOCKAGE
> 1)
3234 new_ready
= schedule_select (ready
, new_ready
, clock
, file
);
3238 fprintf (file
, "\n");
3239 /* We must set n_ready here, to ensure that sorting always
3240 occurs when we come back to the SCHED_SORT line above. */
3245 n_ready
= new_ready
;
3246 last_scheduled_insn
= insn
= ready
[0];
3248 /* The first insn scheduled becomes the new tail. */
3254 fprintf (file
, ", now");
3255 for (i
= 0; i
< n_ready
; i
++)
3256 fprintf (file
, " %d", INSN_UID (ready
[i
]));
3257 fprintf (file
, "\n");
3260 if (DONE_PRIORITY_P (insn
))
3263 if (reload_completed
== 0)
3265 /* Process this insn, and each insn linked to this one which must
3266 be immediately output after this insn. */
3269 /* First we kill registers set by this insn, and then we
3270 make registers used by this insn live. This is the opposite
3271 order used above because we are traversing the instructions
3274 /* Strictly speaking, we should scan REG_UNUSED notes and make
3275 every register mentioned there live, however, we will just
3276 kill them again immediately below, so there doesn't seem to
3277 be any reason why we bother to do this. */
3279 /* See if this is the last notice we must take of a register. */
3280 if (GET_CODE (PATTERN (insn
)) == SET
3281 || GET_CODE (PATTERN (insn
)) == CLOBBER
)
3282 sched_note_set (b
, PATTERN (insn
), 1);
3283 else if (GET_CODE (PATTERN (insn
)) == PARALLEL
)
3286 for (j
= XVECLEN (PATTERN (insn
), 0) - 1; j
>= 0; j
--)
3287 if (GET_CODE (XVECEXP (PATTERN (insn
), 0, j
)) == SET
3288 || GET_CODE (XVECEXP (PATTERN (insn
), 0, j
)) == CLOBBER
)
3289 sched_note_set (b
, XVECEXP (PATTERN (insn
), 0, j
), 1);
3292 /* This code keeps life analysis information up to date. */
3293 if (GET_CODE (insn
) == CALL_INSN
)
3295 register struct sometimes
*p
;
3297 /* A call kills all call used registers that are not
3298 global or fixed, except for those mentioned in the call
3299 pattern which will be made live again later. */
3300 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
3301 if (call_used_regs
[i
] && ! global_regs
[i
]
3304 CLEAR_REGNO_REG_SET (bb_live_regs
, i
);
3305 SET_REGNO_REG_SET (bb_dead_regs
, i
);
3308 /* Regs live at the time of a call instruction must not
3309 go in a register clobbered by calls. Record this for
3310 all regs now live. Note that insns which are born or
3311 die in a call do not cross a call, so this must be done
3312 after the killings (above) and before the births
3314 p
= regs_sometimes_live
;
3315 for (i
= 0; i
< sometimes_max
; i
++, p
++)
3316 if (REGNO_REG_SET_P (bb_live_regs
, p
->regno
))
3317 p
->calls_crossed
+= 1;
3320 /* Make every register used live, and add REG_DEAD notes for
3321 registers which were not live before we started. */
3322 attach_deaths_insn (insn
);
3324 /* Find registers now made live by that instruction. */
3325 EXECUTE_IF_AND_COMPL_IN_REG_SET (bb_live_regs
, old_live_regs
, 0, i
,
3328 = new_sometimes_live (regs_sometimes_live
,
3331 IOR_REG_SET (old_live_regs
, bb_live_regs
);
3333 /* Count lengths of all regs we are worrying about now,
3334 and handle registers no longer live. */
3336 for (i
= 0; i
< sometimes_max
; i
++)
3338 register struct sometimes
*p
= ®s_sometimes_live
[i
];
3339 int regno
= p
->regno
;
3341 p
->live_length
+= 1;
3343 if (!REGNO_REG_SET_P (bb_live_regs
, p
->regno
))
3345 /* This is the end of one of this register's lifetime
3346 segments. Save the lifetime info collected so far,
3347 and clear its bit in the old_live_regs entry. */
3348 sched_reg_live_length
[regno
] += p
->live_length
;
3349 sched_reg_n_calls_crossed
[regno
] += p
->calls_crossed
;
3350 CLEAR_REGNO_REG_SET (old_live_regs
, p
->regno
);
3352 /* Delete the reg_sometimes_live entry for this reg by
3353 copying the last entry over top of it. */
3354 *p
= regs_sometimes_live
[--sometimes_max
];
3355 /* ...and decrement i so that this newly copied entry
3356 will be processed. */
3362 insn
= PREV_INSN (insn
);
3364 while (SCHED_GROUP_P (link
));
3366 /* Set INSN back to the insn we are scheduling now. */
3370 /* Schedule INSN. Remove it from the ready list. */
3375 NEXT_INSN (insn
) = last
;
3376 PREV_INSN (last
) = insn
;
3378 /* Everything that precedes INSN now either becomes "ready", if
3379 it can execute immediately before INSN, or "pending", if
3380 there must be a delay. Give INSN high enough priority that
3381 at least one (maybe more) reg-killing insns can be launched
3382 ahead of all others. Mark INSN as scheduled by changing its
3384 INSN_PRIORITY (insn
) = LAUNCH_PRIORITY
;
3385 new_ready
= schedule_insn (insn
, ready
, n_ready
, clock
);
3386 INSN_PRIORITY (insn
) = DONE_PRIORITY
;
3388 /* Schedule all prior insns that must not be moved. */
3389 if (SCHED_GROUP_P (insn
))
3391 /* Disable these insns from being launched, in case one of the
3392 insns in the group has a dependency on an earlier one. */
3394 while (SCHED_GROUP_P (link
))
3396 /* Disable these insns from being launched by anybody. */
3397 link
= PREV_INSN (link
);
3398 INSN_REF_COUNT (link
) = 0;
3401 /* Now handle each group insn like the main insn was handled
3404 while (SCHED_GROUP_P (link
))
3406 link
= PREV_INSN (link
);
3410 /* ??? Why don't we set LAUNCH_PRIORITY here? */
3411 new_ready
= schedule_insn (link
, ready
, new_ready
, clock
);
3412 INSN_PRIORITY (link
) = DONE_PRIORITY
;
3416 /* Put back NOTE_INSN_SETJMP,
3417 NOTE_INSN_{LOOP,EHREGION}_{BEGIN,END} notes. */
3419 /* To prime the loop. We need to handle INSN and all the insns in the
3421 last
= NEXT_INSN (insn
);
3424 insn
= PREV_INSN (last
);
3426 /* Maintain a valid chain so emit_note_before works.
3427 This is necessary because PREV_INSN (insn) isn't valid
3428 (if ! SCHED_GROUP_P) and if it points to an insn already
3429 scheduled, a circularity will result. */
3430 if (! SCHED_GROUP_P (insn
))
3432 NEXT_INSN (prev_head
) = insn
;
3433 PREV_INSN (insn
) = prev_head
;
3436 last
= reemit_notes (insn
, insn
);
3438 while (SCHED_GROUP_P (insn
));
3443 if (reload_completed
== 0)
3444 finish_sometimes_live (regs_sometimes_live
, sometimes_max
);
3446 /* HEAD is now the first insn in the chain of insns that
3447 been scheduled by the loop above.
3448 TAIL is the last of those insns. */
3451 /* NOTE_LIST is the end of a chain of notes previously found
3452 among the insns. Insert them at the beginning of the insns. */
3455 rtx note_head
= note_list
;
3456 while (PREV_INSN (note_head
))
3457 note_head
= PREV_INSN (note_head
);
3459 PREV_INSN (head
) = note_list
;
3460 NEXT_INSN (note_list
) = head
;
3464 /* There should be no REG_DEAD notes leftover at the end.
3465 In practice, this can occur as the result of bugs in flow, combine.c,
3466 and/or sched.c. The values of the REG_DEAD notes remaining are
3467 meaningless, because dead_notes is just used as a free list. */
3469 if (dead_notes
!= 0)
3473 if (new_needs
& NEED_HEAD
)
3474 basic_block_head
[b
] = head
;
3475 PREV_INSN (head
) = prev_head
;
3476 NEXT_INSN (prev_head
) = head
;
3478 if (new_needs
& NEED_TAIL
)
3479 basic_block_end
[b
] = tail
;
3480 NEXT_INSN (tail
) = next_tail
;
3481 PREV_INSN (next_tail
) = tail
;
3483 /* Restore the line-number notes of each insn. */
3484 if (write_symbols
!= NO_DEBUG
)
3486 rtx line
, note
, prev
, new;
3489 head
= basic_block_head
[b
];
3490 next_tail
= NEXT_INSN (basic_block_end
[b
]);
3492 /* Determine the current line-number. We want to know the current
3493 line number of the first insn of the block here, in case it is
3494 different from the true line number that was saved earlier. If
3495 different, then we need a line number note before the first insn
3496 of this block. If it happens to be the same, then we don't want to
3497 emit another line number note here. */
3498 for (line
= head
; line
; line
= PREV_INSN (line
))
3499 if (GET_CODE (line
) == NOTE
&& NOTE_LINE_NUMBER (line
) > 0)
3502 /* Walk the insns keeping track of the current line-number and inserting
3503 the line-number notes as needed. */
3504 for (insn
= head
; insn
!= next_tail
; insn
= NEXT_INSN (insn
))
3505 if (GET_CODE (insn
) == NOTE
&& NOTE_LINE_NUMBER (insn
) > 0)
3507 /* This used to emit line number notes before every non-deleted note.
3508 However, this confuses a debugger, because line notes not separated
3509 by real instructions all end up at the same address. I can find no
3510 use for line number notes before other notes, so none are emitted. */
3511 else if (GET_CODE (insn
) != NOTE
3512 && (note
= LINE_NOTE (insn
)) != 0
3515 || NOTE_LINE_NUMBER (note
) != NOTE_LINE_NUMBER (line
)
3516 || NOTE_SOURCE_FILE (note
) != NOTE_SOURCE_FILE (line
)))
3519 prev
= PREV_INSN (insn
);
3520 if (LINE_NOTE (note
))
3522 /* Re-use the original line-number note. */
3523 LINE_NOTE (note
) = 0;
3524 PREV_INSN (note
) = prev
;
3525 NEXT_INSN (prev
) = note
;
3526 PREV_INSN (insn
) = note
;
3527 NEXT_INSN (note
) = insn
;
3532 new = emit_note_after (NOTE_LINE_NUMBER (note
), prev
);
3533 NOTE_SOURCE_FILE (new) = NOTE_SOURCE_FILE (note
);
3534 RTX_INTEGRATED_P (new) = RTX_INTEGRATED_P (note
);
3538 fprintf (file
, ";; added %d line-number notes\n", notes
);
3543 fprintf (file
, ";; total time = %d\n;; new basic block head = %d\n;; new basic block end = %d\n\n",
3544 clock
, INSN_UID (basic_block_head
[b
]), INSN_UID (basic_block_end
[b
]));
3547 /* Yow! We're done! */
3548 free_pending_lists ();
3551 FREE_REG_SET (reg_pending_sets
);
3552 FREE_REG_SET (old_live_regs
);
3557 /* Subroutine of split_hard_reg_notes. Searches X for any reference to
3558 REGNO, returning the rtx of the reference found if any. Otherwise,
3562 regno_use_in (regno
, x
)
3570 if (GET_CODE (x
) == REG
&& REGNO (x
) == regno
)
3573 fmt
= GET_RTX_FORMAT (GET_CODE (x
));
3574 for (i
= GET_RTX_LENGTH (GET_CODE (x
)) - 1; i
>= 0; i
--)
3578 if ((tem
= regno_use_in (regno
, XEXP (x
, i
))))
3581 else if (fmt
[i
] == 'E')
3582 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
3583 if ((tem
= regno_use_in (regno
, XVECEXP (x
, i
, j
))))
3590 /* Subroutine of update_flow_info. Determines whether any new REG_NOTEs are
3591 needed for the hard register mentioned in the note. This can happen
3592 if the reference to the hard register in the original insn was split into
3593 several smaller hard register references in the split insns. */
3596 split_hard_reg_notes (note
, first
, last
, orig_insn
)
3597 rtx note
, first
, last
, orig_insn
;
3599 rtx reg
, temp
, link
;
3600 int n_regs
, i
, new_reg
;
3603 /* Assume that this is a REG_DEAD note. */
3604 if (REG_NOTE_KIND (note
) != REG_DEAD
)
3607 reg
= XEXP (note
, 0);
3609 n_regs
= HARD_REGNO_NREGS (REGNO (reg
), GET_MODE (reg
));
3611 for (i
= 0; i
< n_regs
; i
++)
3613 new_reg
= REGNO (reg
) + i
;
3615 /* Check for references to new_reg in the split insns. */
3616 for (insn
= last
; ; insn
= PREV_INSN (insn
))
3618 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i'
3619 && (temp
= regno_use_in (new_reg
, PATTERN (insn
))))
3621 /* Create a new reg dead note here. */
3622 link
= rtx_alloc (EXPR_LIST
);
3623 PUT_REG_NOTE_KIND (link
, REG_DEAD
);
3624 XEXP (link
, 0) = temp
;
3625 XEXP (link
, 1) = REG_NOTES (insn
);
3626 REG_NOTES (insn
) = link
;
3628 /* If killed multiple registers here, then add in the excess. */
3629 i
+= HARD_REGNO_NREGS (REGNO (temp
), GET_MODE (temp
)) - 1;
3633 /* It isn't mentioned anywhere, so no new reg note is needed for
3641 /* Subroutine of update_flow_info. Determines whether a SET or CLOBBER in an
3642 insn created by splitting needs a REG_DEAD or REG_UNUSED note added. */
3645 new_insn_dead_notes (pat
, insn
, last
, orig_insn
)
3646 rtx pat
, insn
, last
, orig_insn
;
3650 /* PAT is either a CLOBBER or a SET here. */
3651 dest
= XEXP (pat
, 0);
3653 while (GET_CODE (dest
) == ZERO_EXTRACT
|| GET_CODE (dest
) == SUBREG
3654 || GET_CODE (dest
) == STRICT_LOW_PART
3655 || GET_CODE (dest
) == SIGN_EXTRACT
)
3656 dest
= XEXP (dest
, 0);
3658 if (GET_CODE (dest
) == REG
)
3660 for (tem
= last
; tem
!= insn
; tem
= PREV_INSN (tem
))
3662 if (GET_RTX_CLASS (GET_CODE (tem
)) == 'i'
3663 && reg_overlap_mentioned_p (dest
, PATTERN (tem
))
3664 && (set
= single_set (tem
)))
3666 rtx tem_dest
= SET_DEST (set
);
3668 while (GET_CODE (tem_dest
) == ZERO_EXTRACT
3669 || GET_CODE (tem_dest
) == SUBREG
3670 || GET_CODE (tem_dest
) == STRICT_LOW_PART
3671 || GET_CODE (tem_dest
) == SIGN_EXTRACT
)
3672 tem_dest
= XEXP (tem_dest
, 0);
3674 if (! rtx_equal_p (tem_dest
, dest
))
3676 /* Use the same scheme as combine.c, don't put both REG_DEAD
3677 and REG_UNUSED notes on the same insn. */
3678 if (! find_regno_note (tem
, REG_UNUSED
, REGNO (dest
))
3679 && ! find_regno_note (tem
, REG_DEAD
, REGNO (dest
)))
3681 rtx note
= rtx_alloc (EXPR_LIST
);
3682 PUT_REG_NOTE_KIND (note
, REG_DEAD
);
3683 XEXP (note
, 0) = dest
;
3684 XEXP (note
, 1) = REG_NOTES (tem
);
3685 REG_NOTES (tem
) = note
;
3687 /* The reg only dies in one insn, the last one that uses
3691 else if (reg_overlap_mentioned_p (dest
, SET_SRC (set
)))
3692 /* We found an instruction that both uses the register,
3693 and sets it, so no new REG_NOTE is needed for this set. */
3697 /* If this is a set, it must die somewhere, unless it is the dest of
3698 the original insn, and hence is live after the original insn. Abort
3699 if it isn't supposed to be live after the original insn.
3701 If this is a clobber, then just add a REG_UNUSED note. */
3704 int live_after_orig_insn
= 0;
3705 rtx pattern
= PATTERN (orig_insn
);
3708 if (GET_CODE (pat
) == CLOBBER
)
3710 rtx note
= rtx_alloc (EXPR_LIST
);
3711 PUT_REG_NOTE_KIND (note
, REG_UNUSED
);
3712 XEXP (note
, 0) = dest
;
3713 XEXP (note
, 1) = REG_NOTES (insn
);
3714 REG_NOTES (insn
) = note
;
3718 /* The original insn could have multiple sets, so search the
3719 insn for all sets. */
3720 if (GET_CODE (pattern
) == SET
)
3722 if (reg_overlap_mentioned_p (dest
, SET_DEST (pattern
)))
3723 live_after_orig_insn
= 1;
3725 else if (GET_CODE (pattern
) == PARALLEL
)
3727 for (i
= 0; i
< XVECLEN (pattern
, 0); i
++)
3728 if (GET_CODE (XVECEXP (pattern
, 0, i
)) == SET
3729 && reg_overlap_mentioned_p (dest
,
3730 SET_DEST (XVECEXP (pattern
,
3732 live_after_orig_insn
= 1;
3735 if (! live_after_orig_insn
)
3741 /* Subroutine of update_flow_info. Update the value of reg_n_sets for all
3742 registers modified by X. INC is -1 if the containing insn is being deleted,
3743 and is 1 if the containing insn is a newly generated insn. */
3746 update_n_sets (x
, inc
)
3750 rtx dest
= SET_DEST (x
);
3752 while (GET_CODE (dest
) == STRICT_LOW_PART
|| GET_CODE (dest
) == SUBREG
3753 || GET_CODE (dest
) == ZERO_EXTRACT
|| GET_CODE (dest
) == SIGN_EXTRACT
)
3754 dest
= SUBREG_REG (dest
);
3756 if (GET_CODE (dest
) == REG
)
3758 int regno
= REGNO (dest
);
3760 if (regno
< FIRST_PSEUDO_REGISTER
)
3763 int endregno
= regno
+ HARD_REGNO_NREGS (regno
, GET_MODE (dest
));
3765 for (i
= regno
; i
< endregno
; i
++)
3766 REG_N_SETS (i
) += inc
;
3769 REG_N_SETS (regno
) += inc
;
3773 /* Updates all flow-analysis related quantities (including REG_NOTES) for
3774 the insns from FIRST to LAST inclusive that were created by splitting
3775 ORIG_INSN. NOTES are the original REG_NOTES. */
3778 update_flow_info (notes
, first
, last
, orig_insn
)
3785 rtx orig_dest
, temp
;
3788 /* Get and save the destination set by the original insn. */
3790 orig_dest
= single_set (orig_insn
);
3792 orig_dest
= SET_DEST (orig_dest
);
3794 /* Move REG_NOTES from the original insn to where they now belong. */
3796 for (note
= notes
; note
; note
= next
)
3798 next
= XEXP (note
, 1);
3799 switch (REG_NOTE_KIND (note
))
3803 /* Move these notes from the original insn to the last new insn where
3804 the register is now set. */
3806 for (insn
= last
; ; insn
= PREV_INSN (insn
))
3808 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i'
3809 && reg_mentioned_p (XEXP (note
, 0), PATTERN (insn
)))
3811 /* If this note refers to a multiple word hard register, it
3812 may have been split into several smaller hard register
3813 references, so handle it specially. */
3814 temp
= XEXP (note
, 0);
3815 if (REG_NOTE_KIND (note
) == REG_DEAD
3816 && GET_CODE (temp
) == REG
3817 && REGNO (temp
) < FIRST_PSEUDO_REGISTER
3818 && HARD_REGNO_NREGS (REGNO (temp
), GET_MODE (temp
)) > 1)
3819 split_hard_reg_notes (note
, first
, last
, orig_insn
);
3822 XEXP (note
, 1) = REG_NOTES (insn
);
3823 REG_NOTES (insn
) = note
;
3826 /* Sometimes need to convert REG_UNUSED notes to REG_DEAD
3828 /* ??? This won't handle multiple word registers correctly,
3829 but should be good enough for now. */
3830 if (REG_NOTE_KIND (note
) == REG_UNUSED
3831 && GET_CODE (XEXP (note
, 0)) != SCRATCH
3832 && ! dead_or_set_p (insn
, XEXP (note
, 0)))
3833 PUT_REG_NOTE_KIND (note
, REG_DEAD
);
3835 /* The reg only dies in one insn, the last one that uses
3839 /* It must die somewhere, fail it we couldn't find where it died.
3841 If this is a REG_UNUSED note, then it must be a temporary
3842 register that was not needed by this instantiation of the
3843 pattern, so we can safely ignore it. */
3846 /* After reload, REG_DEAD notes come sometimes an
3847 instruction after the register actually dies. */
3848 if (reload_completed
&& REG_NOTE_KIND (note
) == REG_DEAD
)
3850 XEXP (note
, 1) = REG_NOTES (insn
);
3851 REG_NOTES (insn
) = note
;
3855 if (REG_NOTE_KIND (note
) != REG_UNUSED
)
3864 /* If the insn that set the register to 0 was deleted, this
3865 note cannot be relied on any longer. The destination might
3866 even have been moved to memory.
3867 This was observed for SH4 with execute/920501-6.c compilation,
3868 -O2 -fomit-frame-pointer -finline-functions . */
3869 if (GET_CODE (XEXP (note
, 0)) == NOTE
3870 || INSN_DELETED_P (XEXP (note
, 0)))
3872 /* This note applies to the dest of the original insn. Find the
3873 first new insn that now has the same dest, and move the note
3879 for (insn
= first
; ; insn
= NEXT_INSN (insn
))
3881 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i'
3882 && (temp
= single_set (insn
))
3883 && rtx_equal_p (SET_DEST (temp
), orig_dest
))
3885 XEXP (note
, 1) = REG_NOTES (insn
);
3886 REG_NOTES (insn
) = note
;
3887 /* The reg is only zero before one insn, the first that
3891 /* If this note refers to a multiple word hard
3892 register, it may have been split into several smaller
3893 hard register references. We could split the notes,
3894 but simply dropping them is good enough. */
3895 if (GET_CODE (orig_dest
) == REG
3896 && REGNO (orig_dest
) < FIRST_PSEUDO_REGISTER
3897 && HARD_REGNO_NREGS (REGNO (orig_dest
),
3898 GET_MODE (orig_dest
)) > 1)
3900 /* It must be set somewhere, fail if we couldn't find where it
3909 /* A REG_EQUIV or REG_EQUAL note on an insn with more than one
3910 set is meaningless. Just drop the note. */
3914 case REG_NO_CONFLICT
:
3915 /* These notes apply to the dest of the original insn. Find the last
3916 new insn that now has the same dest, and move the note there. */
3921 for (insn
= last
; ; insn
= PREV_INSN (insn
))
3923 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i'
3924 && (temp
= single_set (insn
))
3925 && rtx_equal_p (SET_DEST (temp
), orig_dest
))
3927 XEXP (note
, 1) = REG_NOTES (insn
);
3928 REG_NOTES (insn
) = note
;
3929 /* Only put this note on one of the new insns. */
3933 /* The original dest must still be set someplace. Abort if we
3934 couldn't find it. */
3937 /* However, if this note refers to a multiple word hard
3938 register, it may have been split into several smaller
3939 hard register references. We could split the notes,
3940 but simply dropping them is good enough. */
3941 if (GET_CODE (orig_dest
) == REG
3942 && REGNO (orig_dest
) < FIRST_PSEUDO_REGISTER
3943 && HARD_REGNO_NREGS (REGNO (orig_dest
),
3944 GET_MODE (orig_dest
)) > 1)
3946 /* Likewise for multi-word memory references. */
3947 if (GET_CODE (orig_dest
) == MEM
3948 && SIZE_FOR_MODE (orig_dest
) > MOVE_MAX
)
3956 /* Move a REG_LIBCALL note to the first insn created, and update
3957 the corresponding REG_RETVAL note. */
3958 XEXP (note
, 1) = REG_NOTES (first
);
3959 REG_NOTES (first
) = note
;
3961 insn
= XEXP (note
, 0);
3962 note
= find_reg_note (insn
, REG_RETVAL
, NULL_RTX
);
3964 XEXP (note
, 0) = first
;
3967 case REG_EXEC_COUNT
:
3968 /* Move a REG_EXEC_COUNT note to the first insn created. */
3969 XEXP (note
, 1) = REG_NOTES (first
);
3970 REG_NOTES (first
) = note
;
3974 /* Move a REG_RETVAL note to the last insn created, and update
3975 the corresponding REG_LIBCALL note. */
3976 XEXP (note
, 1) = REG_NOTES (last
);
3977 REG_NOTES (last
) = note
;
3979 insn
= XEXP (note
, 0);
3980 note
= find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
);
3982 XEXP (note
, 0) = last
;
3987 /* This should be moved to whichever instruction is a JUMP_INSN. */
3989 for (insn
= last
; ; insn
= PREV_INSN (insn
))
3991 if (GET_CODE (insn
) == JUMP_INSN
)
3993 XEXP (note
, 1) = REG_NOTES (insn
);
3994 REG_NOTES (insn
) = note
;
3995 /* Only put this note on one of the new insns. */
3998 /* Fail if we couldn't find a JUMP_INSN. */
4005 /* reload sometimes leaves obsolete REG_INC notes around. */
4006 if (reload_completed
)
4008 /* This should be moved to whichever instruction now has the
4009 increment operation. */
4013 /* Should be moved to the new insn(s) which use the label. */
4014 for (insn
= first
; insn
!= NEXT_INSN (last
); insn
= NEXT_INSN (insn
))
4015 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i'
4016 && reg_mentioned_p (XEXP (note
, 0), PATTERN (insn
)))
4017 REG_NOTES (insn
) = gen_rtx_EXPR_LIST (REG_LABEL
,
4024 /* These two notes will never appear until after reorg, so we don't
4025 have to handle them here. */
4031 /* Each new insn created, except the last, has a new set. If the destination
4032 is a register, then this reg is now live across several insns, whereas
4033 previously the dest reg was born and died within the same insn. To
4034 reflect this, we now need a REG_DEAD note on the insn where this
4037 Similarly, the new insns may have clobbers that need REG_UNUSED notes. */
4039 for (insn
= first
; insn
!= last
; insn
= NEXT_INSN (insn
))
4044 pat
= PATTERN (insn
);
4045 if (GET_CODE (pat
) == SET
|| GET_CODE (pat
) == CLOBBER
)
4046 new_insn_dead_notes (pat
, insn
, last
, orig_insn
);
4047 else if (GET_CODE (pat
) == PARALLEL
)
4049 for (i
= 0; i
< XVECLEN (pat
, 0); i
++)
4050 if (GET_CODE (XVECEXP (pat
, 0, i
)) == SET
4051 || GET_CODE (XVECEXP (pat
, 0, i
)) == CLOBBER
)
4052 new_insn_dead_notes (XVECEXP (pat
, 0, i
), insn
, last
, orig_insn
);
4056 /* If any insn, except the last, uses the register set by the last insn,
4057 then we need a new REG_DEAD note on that insn. In this case, there
4058 would not have been a REG_DEAD note for this register in the original
4059 insn because it was used and set within one insn. */
4061 set
= single_set (last
);
4064 rtx dest
= SET_DEST (set
);
4066 while (GET_CODE (dest
) == ZERO_EXTRACT
|| GET_CODE (dest
) == SUBREG
4067 || GET_CODE (dest
) == STRICT_LOW_PART
4068 || GET_CODE (dest
) == SIGN_EXTRACT
)
4069 dest
= XEXP (dest
, 0);
4071 if (GET_CODE (dest
) == REG
4072 /* Global registers are always live, so the code below does not
4074 && (REGNO (dest
) >= FIRST_PSEUDO_REGISTER
4075 || ! global_regs
[REGNO (dest
)]))
4077 rtx stop_insn
= PREV_INSN (first
);
4079 /* If the last insn uses the register that it is setting, then
4080 we don't want to put a REG_DEAD note there. Search backwards
4081 to find the first insn that sets but does not use DEST. */
4084 if (reg_overlap_mentioned_p (dest
, SET_SRC (set
)))
4086 for (insn
= PREV_INSN (insn
); insn
!= first
;
4087 insn
= PREV_INSN (insn
))
4089 if ((set
= single_set (insn
))
4090 && reg_mentioned_p (dest
, SET_DEST (set
))
4091 && ! reg_overlap_mentioned_p (dest
, SET_SRC (set
)))
4096 /* Now find the first insn that uses but does not set DEST. */
4098 for (insn
= PREV_INSN (insn
); insn
!= stop_insn
;
4099 insn
= PREV_INSN (insn
))
4101 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i'
4102 && reg_mentioned_p (dest
, PATTERN (insn
))
4103 && (set
= single_set (insn
)))
4105 rtx insn_dest
= SET_DEST (set
);
4107 while (GET_CODE (insn_dest
) == ZERO_EXTRACT
4108 || GET_CODE (insn_dest
) == SUBREG
4109 || GET_CODE (insn_dest
) == STRICT_LOW_PART
4110 || GET_CODE (insn_dest
) == SIGN_EXTRACT
)
4111 insn_dest
= XEXP (insn_dest
, 0);
4113 if (insn_dest
!= dest
)
4115 note
= rtx_alloc (EXPR_LIST
);
4116 PUT_REG_NOTE_KIND (note
, REG_DEAD
);
4117 XEXP (note
, 0) = dest
;
4118 XEXP (note
, 1) = REG_NOTES (insn
);
4119 REG_NOTES (insn
) = note
;
4120 /* The reg only dies in one insn, the last one
4129 /* If the original dest is modifying a multiple register target, and the
4130 original instruction was split such that the original dest is now set
4131 by two or more SUBREG sets, then the split insns no longer kill the
4132 destination of the original insn.
4134 In this case, if there exists an instruction in the same basic block,
4135 before the split insn, which uses the original dest, and this use is
4136 killed by the original insn, then we must remove the REG_DEAD note on
4137 this insn, because it is now superfluous.
4139 This does not apply when a hard register gets split, because the code
4140 knows how to handle overlapping hard registers properly. */
4141 if (orig_dest
&& GET_CODE (orig_dest
) == REG
)
4143 int found_orig_dest
= 0;
4144 int found_split_dest
= 0;
4146 for (insn
= first
; ; insn
= NEXT_INSN (insn
))
4148 rtx pat
= PATTERN (insn
);
4149 int i
= GET_CODE (pat
) == PARALLEL
? XVECLEN (pat
, 0) : 0;
4153 if (GET_CODE (set
) == SET
)
4155 if (GET_CODE (SET_DEST (set
)) == REG
4156 && REGNO (SET_DEST (set
)) == REGNO (orig_dest
))
4158 found_orig_dest
= 1;
4161 else if (GET_CODE (SET_DEST (set
)) == SUBREG
4162 && SUBREG_REG (SET_DEST (set
)) == orig_dest
)
4164 found_split_dest
= 1;
4170 set
= XVECEXP (pat
, 0, i
);
4177 if (found_split_dest
)
4179 /* Search backwards from FIRST, looking for the first insn that uses
4180 the original dest. Stop if we pass a CODE_LABEL or a JUMP_INSN.
4181 If we find an insn, and it has a REG_DEAD note, then delete the
4184 for (insn
= first
; insn
; insn
= PREV_INSN (insn
))
4186 if (GET_CODE (insn
) == CODE_LABEL
4187 || GET_CODE (insn
) == JUMP_INSN
)
4189 else if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i'
4190 && reg_mentioned_p (orig_dest
, insn
))
4192 note
= find_regno_note (insn
, REG_DEAD
, REGNO (orig_dest
));
4194 remove_note (insn
, note
);
4198 else if (! found_orig_dest
)
4200 /* This should never happen. */
4205 /* Update reg_n_sets. This is necessary to prevent local alloc from
4206 converting REG_EQUAL notes to REG_EQUIV when splitting has modified
4207 a reg from set once to set multiple times. */
4210 rtx x
= PATTERN (orig_insn
);
4211 RTX_CODE code
= GET_CODE (x
);
4213 if (code
== SET
|| code
== CLOBBER
)
4214 update_n_sets (x
, -1);
4215 else if (code
== PARALLEL
)
4218 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
4220 code
= GET_CODE (XVECEXP (x
, 0, i
));
4221 if (code
== SET
|| code
== CLOBBER
)
4222 update_n_sets (XVECEXP (x
, 0, i
), -1);
4226 for (insn
= first
; ; insn
= NEXT_INSN (insn
))
4229 code
= GET_CODE (x
);
4231 if (code
== SET
|| code
== CLOBBER
)
4232 update_n_sets (x
, 1);
4233 else if (code
== PARALLEL
)
4236 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
4238 code
= GET_CODE (XVECEXP (x
, 0, i
));
4239 if (code
== SET
|| code
== CLOBBER
)
4240 update_n_sets (XVECEXP (x
, 0, i
), 1);
4250 /* The one entry point in this file. DUMP_FILE is the dump file for
4254 schedule_insns (dump_file
)
4257 int max_uid
= MAX_INSNS_PER_SPLIT
* (get_max_uid () + 1);
4261 /* Taking care of this degenerate case makes the rest of
4262 this code simpler. */
4263 if (n_basic_blocks
== 0)
4266 /* Create an insn here so that we can hang dependencies off of it later. */
4267 sched_before_next_call
4268 = gen_rtx_INSN (VOIDmode
, 0, NULL_RTX
, NULL_RTX
,
4269 NULL_RTX
, 0, NULL_RTX
, NULL_RTX
);
4271 /* Initialize the unused_*_lists. We can't use the ones left over from
4272 the previous function, because gcc has freed that memory. We can use
4273 the ones left over from the first sched pass in the second pass however,
4274 so only clear them on the first sched pass. The first pass is before
4275 reload if flag_schedule_insns is set, otherwise it is afterwards. */
4277 if (reload_completed
== 0 || ! flag_schedule_insns
)
4279 unused_insn_list
= 0;
4280 unused_expr_list
= 0;
4283 /* We create no insns here, only reorder them, so we
4284 remember how far we can cut back the stack on exit. */
4286 /* Allocate data for this pass. See comments, above,
4287 for what these vectors do. */
4288 insn_luid
= (int *) alloca (max_uid
* sizeof (int));
4289 insn_priority
= (int *) alloca (max_uid
* sizeof (int));
4290 insn_tick
= (int *) alloca (max_uid
* sizeof (int));
4291 insn_costs
= (short *) alloca (max_uid
* sizeof (short));
4292 insn_units
= (short *) alloca (max_uid
* sizeof (short));
4293 insn_blockage
= (unsigned int *) alloca (max_uid
* sizeof (unsigned int));
4294 insn_ref_count
= (int *) alloca (max_uid
* sizeof (int));
4296 if (reload_completed
== 0)
4298 sched_reg_n_calls_crossed
= (int *) alloca (max_regno
* sizeof (int));
4299 sched_reg_live_length
= (int *) alloca (max_regno
* sizeof (int));
4300 bb_dead_regs
= ALLOCA_REG_SET ();
4301 bb_live_regs
= ALLOCA_REG_SET ();
4302 bzero ((char *) sched_reg_n_calls_crossed
, max_regno
* sizeof (int));
4303 bzero ((char *) sched_reg_live_length
, max_regno
* sizeof (int));
4307 sched_reg_n_calls_crossed
= 0;
4308 sched_reg_live_length
= 0;
4312 init_alias_analysis ();
4314 if (write_symbols
!= NO_DEBUG
)
4318 line_note
= (rtx
*) alloca (max_uid
* sizeof (rtx
));
4319 bzero ((char *) line_note
, max_uid
* sizeof (rtx
));
4320 line_note_head
= (rtx
*) alloca (n_basic_blocks
* sizeof (rtx
));
4321 bzero ((char *) line_note_head
, n_basic_blocks
* sizeof (rtx
));
4323 /* Determine the line-number at the start of each basic block.
4324 This must be computed and saved now, because after a basic block's
4325 predecessor has been scheduled, it is impossible to accurately
4326 determine the correct line number for the first insn of the block. */
4328 for (b
= 0; b
< n_basic_blocks
; b
++)
4329 for (line
= basic_block_head
[b
]; line
; line
= PREV_INSN (line
))
4330 if (GET_CODE (line
) == NOTE
&& NOTE_LINE_NUMBER (line
) > 0)
4332 line_note_head
[b
] = line
;
4337 bzero ((char *) insn_luid
, max_uid
* sizeof (int));
4338 bzero ((char *) insn_priority
, max_uid
* sizeof (int));
4339 bzero ((char *) insn_tick
, max_uid
* sizeof (int));
4340 bzero ((char *) insn_costs
, max_uid
* sizeof (short));
4341 bzero ((char *) insn_units
, max_uid
* sizeof (short));
4342 bzero ((char *) insn_blockage
, max_uid
* sizeof (unsigned int));
4343 bzero ((char *) insn_ref_count
, max_uid
* sizeof (int));
4345 /* Schedule each basic block, block by block. */
4347 /* ??? Add a NOTE after the last insn of the last basic block. It is not
4348 known why this is done. */
4349 /* ??? Perhaps it's done to ensure NEXT_TAIL in schedule_block is a
4352 insn
= basic_block_end
[n_basic_blocks
-1];
4353 if (NEXT_INSN (insn
) == 0
4354 || (GET_CODE (insn
) != NOTE
4355 && GET_CODE (insn
) != CODE_LABEL
4356 /* Don't emit a NOTE if it would end up between an unconditional
4357 jump and a BARRIER. */
4358 && ! (GET_CODE (insn
) == JUMP_INSN
4359 && GET_CODE (NEXT_INSN (insn
)) == BARRIER
)))
4360 emit_note_after (NOTE_INSN_DELETED
, basic_block_end
[n_basic_blocks
-1]);
4362 for (b
= 0; b
< n_basic_blocks
; b
++)
4368 for (insn
= basic_block_head
[b
]; ; insn
= next
)
4373 /* Can't use `next_real_insn' because that
4374 might go across CODE_LABELS and short-out basic blocks. */
4375 next
= NEXT_INSN (insn
);
4376 if (GET_CODE (insn
) != INSN
)
4378 if (insn
== basic_block_end
[b
])
4384 /* Don't split no-op move insns. These should silently disappear
4385 later in final. Splitting such insns would break the code
4386 that handles REG_NO_CONFLICT blocks. */
4387 set
= single_set (insn
);
4388 if (set
&& rtx_equal_p (SET_SRC (set
), SET_DEST (set
)))
4390 if (insn
== basic_block_end
[b
])
4393 /* Nops get in the way while scheduling, so delete them now if
4394 register allocation has already been done. It is too risky
4395 to try to do this before register allocation, and there are
4396 unlikely to be very many nops then anyways. */
4397 if (reload_completed
)
4399 PUT_CODE (insn
, NOTE
);
4400 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
4401 NOTE_SOURCE_FILE (insn
) = 0;
4407 /* Split insns here to get max fine-grain parallelism. */
4408 prev
= PREV_INSN (insn
);
4409 /* It is probably not worthwhile to try to split again in the
4410 second pass. However, if flag_schedule_insns is not set,
4411 the first and only (if any) scheduling pass is after reload. */
4412 if (reload_completed
== 0 || ! flag_schedule_insns
)
4414 rtx last
, first
= PREV_INSN (insn
);
4415 rtx notes
= REG_NOTES (insn
);
4417 last
= try_split (PATTERN (insn
), insn
, 1);
4420 /* try_split returns the NOTE that INSN became. */
4421 first
= NEXT_INSN (first
);
4422 update_flow_info (notes
, first
, last
, insn
);
4424 PUT_CODE (insn
, NOTE
);
4425 NOTE_SOURCE_FILE (insn
) = 0;
4426 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
4427 if (insn
== basic_block_head
[b
])
4428 basic_block_head
[b
] = first
;
4429 if (insn
== basic_block_end
[b
])
4431 basic_block_end
[b
] = last
;
4437 if (insn
== basic_block_end
[b
])
4441 schedule_block (b
, dump_file
);
4448 /* Reposition the prologue and epilogue notes in case we moved the
4449 prologue/epilogue insns. */
4450 if (reload_completed
)
4451 reposition_prologue_and_epilogue_notes (get_insns ());
4453 if (write_symbols
!= NO_DEBUG
)
4456 rtx insn
= get_insns ();
4457 int active_insn
= 0;
4460 /* Walk the insns deleting redundant line-number notes. Many of these
4461 are already present. The remainder tend to occur at basic
4462 block boundaries. */
4463 for (insn
= get_last_insn (); insn
; insn
= PREV_INSN (insn
))
4464 if (GET_CODE (insn
) == NOTE
&& NOTE_LINE_NUMBER (insn
) > 0)
4466 /* If there are no active insns following, INSN is redundant. */
4467 if (active_insn
== 0)
4470 NOTE_SOURCE_FILE (insn
) = 0;
4471 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
4473 /* If the line number is unchanged, LINE is redundant. */
4475 && NOTE_LINE_NUMBER (line
) == NOTE_LINE_NUMBER (insn
)
4476 && NOTE_SOURCE_FILE (line
) == NOTE_SOURCE_FILE (insn
))
4479 NOTE_SOURCE_FILE (line
) = 0;
4480 NOTE_LINE_NUMBER (line
) = NOTE_INSN_DELETED
;
4487 else if (! ((GET_CODE (insn
) == NOTE
4488 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_DELETED
)
4489 || (GET_CODE (insn
) == INSN
4490 && (GET_CODE (PATTERN (insn
)) == USE
4491 || GET_CODE (PATTERN (insn
)) == CLOBBER
))))
4494 if (dump_file
&& notes
)
4495 fprintf (dump_file
, ";; deleted %d line-number notes\n", notes
);
4498 if (reload_completed
== 0)
4501 for (regno
= 0; regno
< max_regno
; regno
++)
4502 if (sched_reg_live_length
[regno
])
4506 if (REG_LIVE_LENGTH (regno
) > sched_reg_live_length
[regno
])
4508 ";; register %d life shortened from %d to %d\n",
4509 regno
, REG_LIVE_LENGTH (regno
),
4510 sched_reg_live_length
[regno
]);
4511 /* Negative values are special; don't overwrite the current
4512 reg_live_length value if it is negative. */
4513 else if (REG_LIVE_LENGTH (regno
) < sched_reg_live_length
[regno
]
4514 && REG_LIVE_LENGTH (regno
) >= 0)
4516 ";; register %d life extended from %d to %d\n",
4517 regno
, REG_LIVE_LENGTH (regno
),
4518 sched_reg_live_length
[regno
]);
4520 if (! REG_N_CALLS_CROSSED (regno
)
4521 && sched_reg_n_calls_crossed
[regno
])
4523 ";; register %d now crosses calls\n", regno
);
4524 else if (REG_N_CALLS_CROSSED (regno
)
4525 && ! sched_reg_n_calls_crossed
[regno
]
4526 && REG_BASIC_BLOCK (regno
) != REG_BLOCK_GLOBAL
)
4528 ";; register %d no longer crosses calls\n", regno
);
4531 /* Negative values are special; don't overwrite the current
4532 reg_live_length value if it is negative. */
4533 if (REG_LIVE_LENGTH (regno
) >= 0)
4534 REG_LIVE_LENGTH (regno
) = sched_reg_live_length
[regno
];
4536 /* We can't change the value of reg_n_calls_crossed to zero for
4537 pseudos which are live in more than one block.
4539 This is because combine might have made an optimization which
4540 invalidated basic_block_live_at_start and reg_n_calls_crossed,
4541 but it does not update them. If we update reg_n_calls_crossed
4542 here, the two variables are now inconsistent, and this might
4543 confuse the caller-save code into saving a register that doesn't
4544 need to be saved. This is only a problem when we zero calls
4545 crossed for a pseudo live in multiple basic blocks.
4547 Alternatively, we could try to correctly update basic block live
4548 at start here in sched, but that seems complicated. */
4549 if (sched_reg_n_calls_crossed
[regno
]
4550 || REG_BASIC_BLOCK (regno
) != REG_BLOCK_GLOBAL
)
4551 REG_N_CALLS_CROSSED (regno
) = sched_reg_n_calls_crossed
[regno
];
4555 if (reload_completed
== 0)
4557 FREE_REG_SET (bb_dead_regs
);
4558 FREE_REG_SET (bb_live_regs
);
4562 #endif /* INSN_SCHEDULING */