1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
21 /* This file contains the data flow analysis pass of the compiler.
22 It computes data flow information
23 which tells combine_instructions which insns to consider combining
24 and controls register allocation.
26 Additional data flow information that is too bulky to record
27 is generated during the analysis, and is used at that time to
28 create autoincrement and autodecrement addressing.
30 The first step is dividing the function into basic blocks.
31 find_basic_blocks does this. Then life_analysis determines
32 where each register is live and where it is dead.
34 ** find_basic_blocks **
36 find_basic_blocks divides the current function's rtl
37 into basic blocks. It records the beginnings and ends of the
38 basic blocks in the vectors basic_block_head and basic_block_end,
39 and the number of blocks in n_basic_blocks.
41 find_basic_blocks also finds any unreachable loops
46 life_analysis is called immediately after find_basic_blocks.
47 It uses the basic block information to determine where each
48 hard or pseudo register is live.
50 ** live-register info **
52 The information about where each register is live is in two parts:
53 the REG_NOTES of insns, and the vector basic_block_live_at_start.
55 basic_block_live_at_start has an element for each basic block,
56 and the element is a bit-vector with a bit for each hard or pseudo
57 register. The bit is 1 if the register is live at the beginning
60 Two types of elements can be added to an insn's REG_NOTES.
61 A REG_DEAD note is added to an insn's REG_NOTES for any register
62 that meets both of two conditions: The value in the register is not
63 needed in subsequent insns and the insn does not replace the value in
64 the register (in the case of multi-word hard registers, the value in
65 each register must be replaced by the insn to avoid a REG_DEAD note).
67 In the vast majority of cases, an object in a REG_DEAD note will be
68 used somewhere in the insn. The (rare) exception to this is if an
69 insn uses a multi-word hard register and only some of the registers are
70 needed in subsequent insns. In that case, REG_DEAD notes will be
71 provided for those hard registers that are not subsequently needed.
72 Partial REG_DEAD notes of this type do not occur when an insn sets
73 only some of the hard registers used in such a multi-word operand;
74 omitting REG_DEAD notes for objects stored in an insn is optional and
75 the desire to do so does not justify the complexity of the partial
78 REG_UNUSED notes are added for each register that is set by the insn
79 but is unused subsequently (if every register set by the insn is unused
80 and the insn does not reference memory or have some other side-effect,
81 the insn is deleted instead). If only part of a multi-word hard
82 register is used in a subsequent insn, REG_UNUSED notes are made for
83 the parts that will not be used.
85 To determine which registers are live after any insn, one can
86 start from the beginning of the basic block and scan insns, noting
87 which registers are set by each insn and which die there.
89 ** Other actions of life_analysis **
91 life_analysis sets up the LOG_LINKS fields of insns because the
92 information needed to do so is readily available.
94 life_analysis deletes insns whose only effect is to store a value
97 life_analysis notices cases where a reference to a register as
98 a memory address can be combined with a preceding or following
99 incrementation or decrementation of the register. The separate
100 instruction to increment or decrement is deleted and the address
101 is changed to a POST_INC or similar rtx.
103 Each time an incrementing or decrementing address is created,
104 a REG_INC element is added to the insn's REG_NOTES list.
106 life_analysis fills in certain vectors containing information about
107 register usage: reg_n_refs, reg_n_deaths, reg_n_sets, reg_live_length,
108 reg_n_calls_crosses and reg_basic_block. */
113 #include "basic-block.h"
114 #include "insn-config.h"
116 #include "hard-reg-set.h"
121 #define obstack_chunk_alloc xmalloc
122 #define obstack_chunk_free free
124 /* List of labels that must never be deleted. */
125 extern rtx forced_labels
;
127 /* Get the basic block number of an insn.
128 This info should not be expected to remain available
129 after the end of life_analysis. */
131 /* This is the limit of the allocated space in the following two arrays. */
133 static int max_uid_for_flow
;
135 #define BLOCK_NUM(INSN) uid_block_number[INSN_UID (INSN)]
137 /* This is where the BLOCK_NUM values are really stored.
138 This is set up by find_basic_blocks and used there and in life_analysis,
141 static int *uid_block_number
;
143 /* INSN_VOLATILE (insn) is 1 if the insn refers to anything volatile. */
145 #define INSN_VOLATILE(INSN) uid_volatile[INSN_UID (INSN)]
146 static char *uid_volatile
;
148 /* Number of basic blocks in the current function. */
152 /* Maximum register number used in this function, plus one. */
156 /* Maximum number of SCRATCH rtx's used in any basic block of this function. */
160 /* Number of SCRATCH rtx's in the current block. */
162 static int num_scratch
;
164 /* Indexed by n, gives number of basic block that (REG n) is used in.
165 If the value is REG_BLOCK_GLOBAL (-2),
166 it means (REG n) is used in more than one basic block.
167 REG_BLOCK_UNKNOWN (-1) means it hasn't been seen yet so we don't know.
168 This information remains valid for the rest of the compilation
169 of the current function; it is used to control register allocation. */
171 int *reg_basic_block
;
173 /* Indexed by n, gives number of times (REG n) is used or set, each
174 weighted by its loop-depth.
175 This information remains valid for the rest of the compilation
176 of the current function; it is used to control register allocation. */
180 /* Indexed by N; says whether a psuedo register N was ever used
181 within a SUBREG that changes the size of the reg. Some machines prohibit
182 such objects to be in certain (usually floating-point) registers. */
184 char *reg_changes_size
;
186 /* Indexed by N, gives number of places register N dies.
187 This information remains valid for the rest of the compilation
188 of the current function; it is used to control register allocation. */
192 /* Indexed by N, gives 1 if that reg is live across any CALL_INSNs.
193 This information remains valid for the rest of the compilation
194 of the current function; it is used to control register allocation. */
196 int *reg_n_calls_crossed
;
198 /* Total number of instructions at which (REG n) is live.
199 The larger this is, the less priority (REG n) gets for
200 allocation in a real register.
201 This information remains valid for the rest of the compilation
202 of the current function; it is used to control register allocation.
204 local-alloc.c may alter this number to change the priority.
206 Negative values are special.
207 -1 is used to mark a pseudo reg which has a constant or memory equivalent
208 and is used infrequently enough that it should not get a hard register.
209 -2 is used to mark a pseudo reg for a parameter, when a frame pointer
210 is not required. global.c makes an allocno for this but does
211 not try to assign a hard register to it. */
213 int *reg_live_length
;
215 /* Element N is the next insn that uses (hard or pseudo) register number N
216 within the current basic block; or zero, if there is no such insn.
217 This is valid only during the final backward scan in propagate_block. */
219 static rtx
*reg_next_use
;
221 /* Size of a regset for the current function,
222 in (1) bytes and (2) elements. */
227 /* Element N is first insn in basic block N.
228 This info lasts until we finish compiling the function. */
230 rtx
*basic_block_head
;
232 /* Element N is last insn in basic block N.
233 This info lasts until we finish compiling the function. */
235 rtx
*basic_block_end
;
237 /* Element N is a regset describing the registers live
238 at the start of basic block N.
239 This info lasts until we finish compiling the function. */
241 regset
*basic_block_live_at_start
;
243 /* Regset of regs live when calls to `setjmp'-like functions happen. */
245 regset regs_live_at_setjmp
;
247 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
248 that have to go in the same hard reg.
249 The first two regs in the list are a pair, and the next two
250 are another pair, etc. */
253 /* Element N is nonzero if control can drop into basic block N
254 from the preceding basic block. Freed after life_analysis. */
256 static char *basic_block_drops_in
;
258 /* Element N is depth within loops of the last insn in basic block number N.
259 Freed after life_analysis. */
261 static short *basic_block_loop_depth
;
263 /* Element N nonzero if basic block N can actually be reached.
264 Vector exists only during find_basic_blocks. */
266 static char *block_live_static
;
268 /* Depth within loops of basic block being scanned for lifetime analysis,
269 plus one. This is the weight attached to references to registers. */
271 static int loop_depth
;
273 /* During propagate_block, this is non-zero if the value of CC0 is live. */
277 /* During propagate_block, this contains the last MEM stored into. It
278 is used to eliminate consecutive stores to the same location. */
280 static rtx last_mem_set
;
282 /* Set of registers that may be eliminable. These are handled specially
283 in updating regs_ever_live. */
285 static HARD_REG_SET elim_reg_set
;
287 /* Forward declarations */
288 static void find_basic_blocks
PROTO((rtx
, rtx
));
289 static int uses_reg_or_mem
PROTO((rtx
));
290 static void mark_label_ref
PROTO((rtx
, rtx
, int));
291 static void life_analysis
PROTO((rtx
, int));
292 void allocate_for_life_analysis
PROTO((void));
293 static void init_regset_vector
PROTO((regset
*, regset
, int, int));
294 static void propagate_block
PROTO((regset
, rtx
, rtx
, int,
296 static rtx flow_delete_insn
PROTO((rtx
));
297 static int insn_dead_p
PROTO((rtx
, regset
, int));
298 static int libcall_dead_p
PROTO((rtx
, regset
, rtx
, rtx
));
299 static void mark_set_regs
PROTO((regset
, regset
, rtx
,
301 static void mark_set_1
PROTO((regset
, regset
, rtx
,
303 static void find_auto_inc
PROTO((regset
, rtx
, rtx
));
304 static void mark_used_regs
PROTO((regset
, regset
, rtx
, int, rtx
));
305 static int try_pre_increment_1
PROTO((rtx
));
306 static int try_pre_increment
PROTO((rtx
, rtx
, HOST_WIDE_INT
));
307 static rtx find_use_as_address
PROTO((rtx
, rtx
, HOST_WIDE_INT
));
308 void dump_flow_info
PROTO((FILE *));
310 /* Find basic blocks of the current function and perform data flow analysis.
311 F is the first insn of the function and NREGS the number of register numbers
315 flow_analysis (f
, nregs
, file
)
322 rtx nonlocal_label_list
= nonlocal_label_rtx_list ();
324 #ifdef ELIMINABLE_REGS
325 static struct {int from
, to
; } eliminables
[] = ELIMINABLE_REGS
;
328 /* Record which registers will be eliminated. We use this in
331 CLEAR_HARD_REG_SET (elim_reg_set
);
333 #ifdef ELIMINABLE_REGS
334 for (i
= 0; i
< sizeof eliminables
/ sizeof eliminables
[0]; i
++)
335 SET_HARD_REG_BIT (elim_reg_set
, eliminables
[i
].from
);
337 SET_HARD_REG_BIT (elim_reg_set
, FRAME_POINTER_REGNUM
);
340 /* Count the basic blocks. Also find maximum insn uid value used. */
343 register RTX_CODE prev_code
= JUMP_INSN
;
344 register RTX_CODE code
;
346 max_uid_for_flow
= 0;
348 for (insn
= f
, i
= 0; insn
; insn
= NEXT_INSN (insn
))
350 code
= GET_CODE (insn
);
351 if (INSN_UID (insn
) > max_uid_for_flow
)
352 max_uid_for_flow
= INSN_UID (insn
);
353 if (code
== CODE_LABEL
354 || (GET_RTX_CLASS (code
) == 'i'
355 && (prev_code
== JUMP_INSN
356 || (prev_code
== CALL_INSN
357 && nonlocal_label_list
!= 0)
358 || prev_code
== BARRIER
)))
366 /* Leave space for insns we make in some cases for auto-inc. These cases
367 are rare, so we don't need too much space. */
368 max_uid_for_flow
+= max_uid_for_flow
/ 10;
371 /* Allocate some tables that last till end of compiling this function
372 and some needed only in find_basic_blocks and life_analysis. */
375 basic_block_head
= (rtx
*) oballoc (n_basic_blocks
* sizeof (rtx
));
376 basic_block_end
= (rtx
*) oballoc (n_basic_blocks
* sizeof (rtx
));
377 basic_block_drops_in
= (char *) alloca (n_basic_blocks
);
378 basic_block_loop_depth
= (short *) alloca (n_basic_blocks
* sizeof (short));
380 = (int *) alloca ((max_uid_for_flow
+ 1) * sizeof (int));
381 uid_volatile
= (char *) alloca (max_uid_for_flow
+ 1);
382 bzero (uid_volatile
, max_uid_for_flow
+ 1);
384 find_basic_blocks (f
, nonlocal_label_list
);
385 life_analysis (f
, nregs
);
387 dump_flow_info (file
);
389 basic_block_drops_in
= 0;
390 uid_block_number
= 0;
391 basic_block_loop_depth
= 0;
394 /* Find all basic blocks of the function whose first insn is F.
395 Store the correct data in the tables that describe the basic blocks,
396 set up the chains of references for each CODE_LABEL, and
397 delete any entire basic blocks that cannot be reached.
399 NONLOCAL_LABEL_LIST is the same local variable from flow_analysis. */
402 find_basic_blocks (f
, nonlocal_label_list
)
403 rtx f
, nonlocal_label_list
;
407 register char *block_live
= (char *) alloca (n_basic_blocks
);
408 register char *block_marked
= (char *) alloca (n_basic_blocks
);
409 /* List of label_refs to all labels whose addresses are taken
411 rtx label_value_list
;
413 enum rtx_code prev_code
, code
;
419 label_value_list
= 0;
420 block_live_static
= block_live
;
421 bzero (block_live
, n_basic_blocks
);
422 bzero (block_marked
, n_basic_blocks
);
424 /* Initialize with just block 0 reachable and no blocks marked. */
425 if (n_basic_blocks
> 0)
428 /* Initialize the ref chain of each label to 0. Record where all the
429 blocks start and end and their depth in loops. For each insn, record
430 the block it is in. Also mark as reachable any blocks headed by labels
431 that must not be deleted. */
433 for (insn
= f
, i
= -1, prev_code
= JUMP_INSN
, depth
= 1;
434 insn
; insn
= NEXT_INSN (insn
))
436 code
= GET_CODE (insn
);
439 if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
)
441 else if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_END
)
445 /* A basic block starts at label, or after something that can jump. */
446 else if (code
== CODE_LABEL
447 || (GET_RTX_CLASS (code
) == 'i'
448 && (prev_code
== JUMP_INSN
449 || (prev_code
== CALL_INSN
450 && nonlocal_label_list
!= 0)
451 || prev_code
== BARRIER
)))
453 basic_block_head
[++i
] = insn
;
454 basic_block_end
[i
] = insn
;
455 basic_block_loop_depth
[i
] = depth
;
457 if (code
== CODE_LABEL
)
459 LABEL_REFS (insn
) = insn
;
460 /* Any label that cannot be deleted
461 is considered to start a reachable block. */
462 if (LABEL_PRESERVE_P (insn
))
467 else if (GET_RTX_CLASS (code
) == 'i')
469 basic_block_end
[i
] = insn
;
470 basic_block_loop_depth
[i
] = depth
;
473 if (GET_RTX_CLASS (code
) == 'i')
475 /* Make a list of all labels referred to other than by jumps. */
476 for (note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
477 if (REG_NOTE_KIND (note
) == REG_LABEL
)
478 label_value_list
= gen_rtx (EXPR_LIST
, VOIDmode
, XEXP (note
, 0),
482 BLOCK_NUM (insn
) = i
;
488 if (i
+ 1 != n_basic_blocks
)
491 /* Don't delete the labels (in this function)
492 that are referenced by non-jump instructions. */
494 for (x
= label_value_list
; x
; x
= XEXP (x
, 1))
495 if (! LABEL_REF_NONLOCAL_P (x
))
496 block_live
[BLOCK_NUM (XEXP (x
, 0))] = 1;
498 for (x
= forced_labels
; x
; x
= XEXP (x
, 1))
499 if (! LABEL_REF_NONLOCAL_P (x
))
500 block_live
[BLOCK_NUM (XEXP (x
, 0))] = 1;
502 /* Record which basic blocks control can drop in to. */
504 for (i
= 0; i
< n_basic_blocks
; i
++)
506 for (insn
= PREV_INSN (basic_block_head
[i
]);
507 insn
&& GET_CODE (insn
) == NOTE
; insn
= PREV_INSN (insn
))
510 basic_block_drops_in
[i
] = insn
&& GET_CODE (insn
) != BARRIER
;
513 /* Now find which basic blocks can actually be reached
514 and put all jump insns' LABEL_REFS onto the ref-chains
515 of their target labels. */
517 if (n_basic_blocks
> 0)
519 int something_marked
= 1;
522 /* Find all indirect jump insns and mark them as possibly jumping to all
523 the labels whose addresses are explicitly used. This is because,
524 when there are computed gotos, we can't tell which labels they jump
525 to, of all the possibilities.
527 Tablejumps and casesi insns are OK and we can recognize them by
528 a (use (label_ref)). */
530 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
531 if (GET_CODE (insn
) == JUMP_INSN
)
533 rtx pat
= PATTERN (insn
);
534 int computed_jump
= 0;
536 if (GET_CODE (pat
) == PARALLEL
)
538 int len
= XVECLEN (pat
, 0);
539 int has_use_labelref
= 0;
541 for (i
= len
- 1; i
>= 0; i
--)
542 if (GET_CODE (XVECEXP (pat
, 0, i
)) == USE
543 && (GET_CODE (XEXP (XVECEXP (pat
, 0, i
), 0))
545 has_use_labelref
= 1;
547 if (! has_use_labelref
)
548 for (i
= len
- 1; i
>= 0; i
--)
549 if (GET_CODE (XVECEXP (pat
, 0, i
)) == SET
550 && SET_DEST (XVECEXP (pat
, 0, i
)) == pc_rtx
551 && uses_reg_or_mem (SET_SRC (XVECEXP (pat
, 0, i
))))
554 else if (GET_CODE (pat
) == SET
555 && SET_DEST (pat
) == pc_rtx
556 && uses_reg_or_mem (SET_SRC (pat
)))
561 for (x
= label_value_list
; x
; x
= XEXP (x
, 1))
562 mark_label_ref (gen_rtx (LABEL_REF
, VOIDmode
, XEXP (x
, 0)),
565 for (x
= forced_labels
; x
; x
= XEXP (x
, 1))
566 mark_label_ref (gen_rtx (LABEL_REF
, VOIDmode
, XEXP (x
, 0)),
571 /* Find all call insns and mark them as possibly jumping
572 to all the nonlocal goto handler labels. */
574 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
575 if (GET_CODE (insn
) == CALL_INSN
)
577 for (x
= nonlocal_label_list
; x
; x
= XEXP (x
, 1))
578 mark_label_ref (gen_rtx (LABEL_REF
, VOIDmode
, XEXP (x
, 0)),
581 /* ??? This could be made smarter:
582 in some cases it's possible to tell that certain
583 calls will not do a nonlocal goto.
585 For example, if the nested functions that do the
586 nonlocal gotos do not have their addresses taken, then
587 only calls to those functions or to other nested
588 functions that use them could possibly do nonlocal
592 /* Pass over all blocks, marking each block that is reachable
593 and has not yet been marked.
594 Keep doing this until, in one pass, no blocks have been marked.
595 Then blocks_live and blocks_marked are identical and correct.
596 In addition, all jumps actually reachable have been marked. */
598 while (something_marked
)
600 something_marked
= 0;
601 for (i
= 0; i
< n_basic_blocks
; i
++)
602 if (block_live
[i
] && !block_marked
[i
])
605 something_marked
= 1;
606 if (i
+ 1 < n_basic_blocks
&& basic_block_drops_in
[i
+ 1])
607 block_live
[i
+ 1] = 1;
608 insn
= basic_block_end
[i
];
609 if (GET_CODE (insn
) == JUMP_INSN
)
610 mark_label_ref (PATTERN (insn
), insn
, 0);
614 /* ??? See if we have a "live" basic block that is not reachable.
615 This can happen if it is headed by a label that is preserved or
616 in one of the label lists, but no call or computed jump is in
617 the loop. It's not clear if we can delete the block or not,
618 but don't for now. However, we will mess up register status if
619 it remains unreachable, so add a fake reachability from the
622 for (i
= 1; i
< n_basic_blocks
; i
++)
623 if (block_live
[i
] && ! basic_block_drops_in
[i
]
624 && GET_CODE (basic_block_head
[i
]) == CODE_LABEL
625 && LABEL_REFS (basic_block_head
[i
]) == basic_block_head
[i
])
626 basic_block_drops_in
[i
] = 1;
628 /* Now delete the code for any basic blocks that can't be reached.
629 They can occur because jump_optimize does not recognize
630 unreachable loops as unreachable. */
633 for (i
= 0; i
< n_basic_blocks
; i
++)
638 /* Delete the insns in a (non-live) block. We physically delete
639 every non-note insn except the start and end (so
640 basic_block_head/end needn't be updated), we turn the latter
641 into NOTE_INSN_DELETED notes.
642 We use to "delete" the insns by turning them into notes, but
643 we may be deleting lots of insns that subsequent passes would
644 otherwise have to process. Secondly, lots of deleted blocks in
645 a row can really slow down propagate_block since it will
646 otherwise process insn-turned-notes multiple times when it
647 looks for loop begin/end notes. */
648 if (basic_block_head
[i
] != basic_block_end
[i
])
650 insn
= NEXT_INSN (basic_block_head
[i
]);
651 while (insn
!= basic_block_end
[i
])
653 if (GET_CODE (insn
) == BARRIER
)
655 else if (GET_CODE (insn
) != NOTE
)
656 insn
= flow_delete_insn (insn
);
658 insn
= NEXT_INSN (insn
);
661 insn
= basic_block_head
[i
];
662 if (GET_CODE (insn
) != NOTE
)
664 /* Turn the head into a deleted insn note. */
665 if (GET_CODE (insn
) == BARRIER
)
667 PUT_CODE (insn
, NOTE
);
668 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
669 NOTE_SOURCE_FILE (insn
) = 0;
671 insn
= basic_block_end
[i
];
672 if (GET_CODE (insn
) != NOTE
)
674 /* Turn the tail into a deleted insn note. */
675 if (GET_CODE (insn
) == BARRIER
)
677 PUT_CODE (insn
, NOTE
);
678 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
679 NOTE_SOURCE_FILE (insn
) = 0;
681 /* BARRIERs are between basic blocks, not part of one.
682 Delete a BARRIER if the preceding jump is deleted.
683 We cannot alter a BARRIER into a NOTE
684 because it is too short; but we can really delete
685 it because it is not part of a basic block. */
686 if (NEXT_INSN (insn
) != 0
687 && GET_CODE (NEXT_INSN (insn
)) == BARRIER
)
688 delete_insn (NEXT_INSN (insn
));
690 /* Each time we delete some basic blocks,
691 see if there is a jump around them that is
692 being turned into a no-op. If so, delete it. */
694 if (block_live
[i
- 1])
697 for (j
= i
+ 1; j
< n_basic_blocks
; j
++)
701 insn
= basic_block_end
[i
- 1];
702 if (GET_CODE (insn
) == JUMP_INSN
703 /* An unconditional jump is the only possibility
704 we must check for, since a conditional one
705 would make these blocks live. */
706 && simplejump_p (insn
)
707 && (label
= XEXP (SET_SRC (PATTERN (insn
)), 0), 1)
708 && INSN_UID (label
) != 0
709 && BLOCK_NUM (label
) == j
)
711 PUT_CODE (insn
, NOTE
);
712 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
713 NOTE_SOURCE_FILE (insn
) = 0;
714 if (GET_CODE (NEXT_INSN (insn
)) != BARRIER
)
716 delete_insn (NEXT_INSN (insn
));
723 /* There are pathalogical cases where one function calling hundreds of
724 nested inline functions can generate lots and lots of unreachable
725 blocks that jump can't delete. Since we don't use sparse matrices
726 a lot of memory will be needed to compile such functions.
727 Implementing sparse matrices is a fair bit of work and it is not
728 clear that they win more than they lose (we don't want to
729 unnecessarily slow down compilation of normal code). By making
730 another pass for the pathalogical case, we can greatly speed up
731 their compilation without hurting normal code. This works because
732 all the insns in the unreachable blocks have either been deleted or
733 turned into notes. */
734 /* ??? The choice of when to make another pass is a bit arbitrary,
735 and was derived from empirical data. */
737 && (deleted
> n_basic_blocks
/ 2 || deleted
> 1000))
740 n_basic_blocks
-= deleted
;
746 /* Subroutines of find_basic_blocks. */
748 /* Return 1 if X contain a REG or MEM that is not in the constant pool. */
754 enum rtx_code code
= GET_CODE (x
);
760 && ! (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
761 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))))
764 fmt
= GET_RTX_FORMAT (code
);
765 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
768 && uses_reg_or_mem (XEXP (x
, i
)))
772 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
773 if (uses_reg_or_mem (XVECEXP (x
, i
, j
)))
780 /* Check expression X for label references;
781 if one is found, add INSN to the label's chain of references.
783 CHECKDUP means check for and avoid creating duplicate references
784 from the same insn. Such duplicates do no serious harm but
785 can slow life analysis. CHECKDUP is set only when duplicates
789 mark_label_ref (x
, insn
, checkdup
)
793 register RTX_CODE code
;
797 /* We can be called with NULL when scanning label_value_list. */
802 if (code
== LABEL_REF
)
804 register rtx label
= XEXP (x
, 0);
806 if (GET_CODE (label
) != CODE_LABEL
)
808 /* If the label was never emitted, this insn is junk,
809 but avoid a crash trying to refer to BLOCK_NUM (label).
810 This can happen as a result of a syntax error
811 and a diagnostic has already been printed. */
812 if (INSN_UID (label
) == 0)
814 CONTAINING_INSN (x
) = insn
;
815 /* if CHECKDUP is set, check for duplicate ref from same insn
818 for (y
= LABEL_REFS (label
); y
!= label
; y
= LABEL_NEXTREF (y
))
819 if (CONTAINING_INSN (y
) == insn
)
821 LABEL_NEXTREF (x
) = LABEL_REFS (label
);
822 LABEL_REFS (label
) = x
;
823 block_live_static
[BLOCK_NUM (label
)] = 1;
827 fmt
= GET_RTX_FORMAT (code
);
828 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
831 mark_label_ref (XEXP (x
, i
), insn
, 0);
835 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
836 mark_label_ref (XVECEXP (x
, i
, j
), insn
, 1);
841 /* Delete INSN by patching it out.
842 Return the next insn. */
845 flow_delete_insn (insn
)
848 /* ??? For the moment we assume we don't have to watch for NULLs here
849 since the start/end of basic blocks aren't deleted like this. */
850 NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
851 PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
852 return NEXT_INSN (insn
);
855 /* Determine which registers are live at the start of each
856 basic block of the function whose first insn is F.
857 NREGS is the number of registers used in F.
858 We allocate the vector basic_block_live_at_start
859 and the regsets that it points to, and fill them with the data.
860 regset_size and regset_bytes are also set here. */
863 life_analysis (f
, nregs
)
870 /* For each basic block, a bitmask of regs
871 live on exit from the block. */
872 regset
*basic_block_live_at_end
;
873 /* For each basic block, a bitmask of regs
874 live on entry to a successor-block of this block.
875 If this does not match basic_block_live_at_end,
876 that must be updated, and the block must be rescanned. */
877 regset
*basic_block_new_live_at_end
;
878 /* For each basic block, a bitmask of regs
879 whose liveness at the end of the basic block
880 can make a difference in which regs are live on entry to the block.
881 These are the regs that are set within the basic block,
882 possibly excluding those that are used after they are set. */
883 regset
*basic_block_significant
;
887 struct obstack flow_obstack
;
889 gcc_obstack_init (&flow_obstack
);
893 bzero (regs_ever_live
, sizeof regs_ever_live
);
895 /* Allocate and zero out many data structures
896 that will record the data from lifetime analysis. */
898 allocate_for_life_analysis ();
900 reg_next_use
= (rtx
*) alloca (nregs
* sizeof (rtx
));
901 bzero ((char *) reg_next_use
, nregs
* sizeof (rtx
));
903 /* Set up several regset-vectors used internally within this function.
904 Their meanings are documented above, with their declarations. */
906 basic_block_live_at_end
907 = (regset
*) alloca (n_basic_blocks
* sizeof (regset
));
909 /* Don't use alloca since that leads to a crash rather than an error message
910 if there isn't enough space.
911 Don't use oballoc since we may need to allocate other things during
912 this function on the temporary obstack. */
913 tem
= (regset
) obstack_alloc (&flow_obstack
, n_basic_blocks
* regset_bytes
);
914 bzero ((char *) tem
, n_basic_blocks
* regset_bytes
);
915 init_regset_vector (basic_block_live_at_end
, tem
,
916 n_basic_blocks
, regset_bytes
);
918 basic_block_new_live_at_end
919 = (regset
*) alloca (n_basic_blocks
* sizeof (regset
));
920 tem
= (regset
) obstack_alloc (&flow_obstack
, n_basic_blocks
* regset_bytes
);
921 bzero ((char *) tem
, n_basic_blocks
* regset_bytes
);
922 init_regset_vector (basic_block_new_live_at_end
, tem
,
923 n_basic_blocks
, regset_bytes
);
925 basic_block_significant
926 = (regset
*) alloca (n_basic_blocks
* sizeof (regset
));
927 tem
= (regset
) obstack_alloc (&flow_obstack
, n_basic_blocks
* regset_bytes
);
928 bzero ((char *) tem
, n_basic_blocks
* regset_bytes
);
929 init_regset_vector (basic_block_significant
, tem
,
930 n_basic_blocks
, regset_bytes
);
932 /* Record which insns refer to any volatile memory
933 or for any reason can't be deleted just because they are dead stores.
934 Also, delete any insns that copy a register to itself. */
936 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
938 enum rtx_code code1
= GET_CODE (insn
);
939 if (code1
== CALL_INSN
)
940 INSN_VOLATILE (insn
) = 1;
941 else if (code1
== INSN
|| code1
== JUMP_INSN
)
943 /* Delete (in effect) any obvious no-op moves. */
944 if (GET_CODE (PATTERN (insn
)) == SET
945 && GET_CODE (SET_DEST (PATTERN (insn
))) == REG
946 && GET_CODE (SET_SRC (PATTERN (insn
))) == REG
947 && REGNO (SET_DEST (PATTERN (insn
))) ==
948 REGNO (SET_SRC (PATTERN (insn
)))
949 /* Insns carrying these notes are useful later on. */
950 && ! find_reg_note (insn
, REG_EQUAL
, NULL_RTX
))
952 PUT_CODE (insn
, NOTE
);
953 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
954 NOTE_SOURCE_FILE (insn
) = 0;
956 else if (GET_CODE (PATTERN (insn
)) == PARALLEL
)
958 /* If nothing but SETs of registers to themselves,
959 this insn can also be deleted. */
960 for (i
= 0; i
< XVECLEN (PATTERN (insn
), 0); i
++)
962 rtx tem
= XVECEXP (PATTERN (insn
), 0, i
);
964 if (GET_CODE (tem
) == USE
965 || GET_CODE (tem
) == CLOBBER
)
968 if (GET_CODE (tem
) != SET
969 || GET_CODE (SET_DEST (tem
)) != REG
970 || GET_CODE (SET_SRC (tem
)) != REG
971 || REGNO (SET_DEST (tem
)) != REGNO (SET_SRC (tem
)))
975 if (i
== XVECLEN (PATTERN (insn
), 0)
976 /* Insns carrying these notes are useful later on. */
977 && ! find_reg_note (insn
, REG_EQUAL
, NULL_RTX
))
979 PUT_CODE (insn
, NOTE
);
980 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
981 NOTE_SOURCE_FILE (insn
) = 0;
984 INSN_VOLATILE (insn
) = volatile_refs_p (PATTERN (insn
));
986 else if (GET_CODE (PATTERN (insn
)) != USE
)
987 INSN_VOLATILE (insn
) = volatile_refs_p (PATTERN (insn
));
988 /* A SET that makes space on the stack cannot be dead.
989 (Such SETs occur only for allocating variable-size data,
990 so they will always have a PLUS or MINUS according to the
991 direction of stack growth.)
992 Even if this function never uses this stack pointer value,
993 signal handlers do! */
994 else if (code1
== INSN
&& GET_CODE (PATTERN (insn
)) == SET
995 && SET_DEST (PATTERN (insn
)) == stack_pointer_rtx
996 #ifdef STACK_GROWS_DOWNWARD
997 && GET_CODE (SET_SRC (PATTERN (insn
))) == MINUS
999 && GET_CODE (SET_SRC (PATTERN (insn
))) == PLUS
1001 && XEXP (SET_SRC (PATTERN (insn
)), 0) == stack_pointer_rtx
)
1002 INSN_VOLATILE (insn
) = 1;
1006 if (n_basic_blocks
> 0)
1007 #ifdef EXIT_IGNORE_STACK
1008 if (! EXIT_IGNORE_STACK
1009 || (! FRAME_POINTER_REQUIRED
&& flag_omit_frame_pointer
))
1012 /* If exiting needs the right stack value,
1013 consider the stack pointer live at the end of the function. */
1014 basic_block_live_at_end
[n_basic_blocks
- 1]
1015 [STACK_POINTER_REGNUM
/ REGSET_ELT_BITS
]
1016 |= (REGSET_ELT_TYPE
) 1 << (STACK_POINTER_REGNUM
% REGSET_ELT_BITS
);
1017 basic_block_new_live_at_end
[n_basic_blocks
- 1]
1018 [STACK_POINTER_REGNUM
/ REGSET_ELT_BITS
]
1019 |= (REGSET_ELT_TYPE
) 1 << (STACK_POINTER_REGNUM
% REGSET_ELT_BITS
);
1022 /* Mark the frame pointer is needed at the end of the function. If
1023 we end up eliminating it, it will be removed from the live list
1024 of each basic block by reload. */
1026 if (n_basic_blocks
> 0)
1028 basic_block_live_at_end
[n_basic_blocks
- 1]
1029 [FRAME_POINTER_REGNUM
/ REGSET_ELT_BITS
]
1030 |= (REGSET_ELT_TYPE
) 1 << (FRAME_POINTER_REGNUM
% REGSET_ELT_BITS
);
1031 basic_block_new_live_at_end
[n_basic_blocks
- 1]
1032 [FRAME_POINTER_REGNUM
/ REGSET_ELT_BITS
]
1033 |= (REGSET_ELT_TYPE
) 1 << (FRAME_POINTER_REGNUM
% REGSET_ELT_BITS
);
1034 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
1035 /* If they are different, also mark the hard frame pointer as live */
1036 basic_block_live_at_end
[n_basic_blocks
- 1]
1037 [HARD_FRAME_POINTER_REGNUM
/ REGSET_ELT_BITS
]
1038 |= (REGSET_ELT_TYPE
) 1 << (HARD_FRAME_POINTER_REGNUM
1040 basic_block_new_live_at_end
[n_basic_blocks
- 1]
1041 [HARD_FRAME_POINTER_REGNUM
/ REGSET_ELT_BITS
]
1042 |= (REGSET_ELT_TYPE
) 1 << (HARD_FRAME_POINTER_REGNUM
1047 /* Mark all global registers as being live at the end of the function
1048 since they may be referenced by our caller. */
1050 if (n_basic_blocks
> 0)
1051 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1054 basic_block_live_at_end
[n_basic_blocks
- 1]
1055 [i
/ REGSET_ELT_BITS
]
1056 |= (REGSET_ELT_TYPE
) 1 << (i
% REGSET_ELT_BITS
);
1057 basic_block_new_live_at_end
[n_basic_blocks
- 1]
1058 [i
/ REGSET_ELT_BITS
]
1059 |= (REGSET_ELT_TYPE
) 1 << (i
% REGSET_ELT_BITS
);
1062 /* Propagate life info through the basic blocks
1063 around the graph of basic blocks.
1065 This is a relaxation process: each time a new register
1066 is live at the end of the basic block, we must scan the block
1067 to determine which registers are, as a consequence, live at the beginning
1068 of that block. These registers must then be marked live at the ends
1069 of all the blocks that can transfer control to that block.
1070 The process continues until it reaches a fixed point. */
1077 for (i
= n_basic_blocks
- 1; i
>= 0; i
--)
1079 int consider
= first_pass
;
1080 int must_rescan
= first_pass
;
1085 /* Set CONSIDER if this block needs thinking about at all
1086 (that is, if the regs live now at the end of it
1087 are not the same as were live at the end of it when
1088 we last thought about it).
1089 Set must_rescan if it needs to be thought about
1090 instruction by instruction (that is, if any additional
1091 reg that is live at the end now but was not live there before
1092 is one of the significant regs of this basic block). */
1094 for (j
= 0; j
< regset_size
; j
++)
1096 register REGSET_ELT_TYPE x
1097 = (basic_block_new_live_at_end
[i
][j
]
1098 & ~basic_block_live_at_end
[i
][j
]);
1101 if (x
& basic_block_significant
[i
][j
])
1113 /* The live_at_start of this block may be changing,
1114 so another pass will be required after this one. */
1119 /* No complete rescan needed;
1120 just record those variables newly known live at end
1121 as live at start as well. */
1122 for (j
= 0; j
< regset_size
; j
++)
1124 register REGSET_ELT_TYPE x
1125 = (basic_block_new_live_at_end
[i
][j
]
1126 & ~basic_block_live_at_end
[i
][j
]);
1127 basic_block_live_at_start
[i
][j
] |= x
;
1128 basic_block_live_at_end
[i
][j
] |= x
;
1133 /* Update the basic_block_live_at_start
1134 by propagation backwards through the block. */
1135 bcopy ((char *) basic_block_new_live_at_end
[i
],
1136 (char *) basic_block_live_at_end
[i
], regset_bytes
);
1137 bcopy ((char *) basic_block_live_at_end
[i
],
1138 (char *) basic_block_live_at_start
[i
], regset_bytes
);
1139 propagate_block (basic_block_live_at_start
[i
],
1140 basic_block_head
[i
], basic_block_end
[i
], 0,
1141 first_pass
? basic_block_significant
[i
]
1147 register rtx jump
, head
;
1149 /* Update the basic_block_new_live_at_end's of the block
1150 that falls through into this one (if any). */
1151 head
= basic_block_head
[i
];
1152 if (basic_block_drops_in
[i
])
1155 for (j
= 0; j
< regset_size
; j
++)
1156 basic_block_new_live_at_end
[i
-1][j
]
1157 |= basic_block_live_at_start
[i
][j
];
1160 /* Update the basic_block_new_live_at_end's of
1161 all the blocks that jump to this one. */
1162 if (GET_CODE (head
) == CODE_LABEL
)
1163 for (jump
= LABEL_REFS (head
);
1165 jump
= LABEL_NEXTREF (jump
))
1167 register int from_block
= BLOCK_NUM (CONTAINING_INSN (jump
));
1169 for (j
= 0; j
< regset_size
; j
++)
1170 basic_block_new_live_at_end
[from_block
][j
]
1171 |= basic_block_live_at_start
[i
][j
];
1181 /* The only pseudos that are live at the beginning of the function are
1182 those that were not set anywhere in the function. local-alloc doesn't
1183 know how to handle these correctly, so mark them as not local to any
1186 if (n_basic_blocks
> 0)
1187 for (i
= FIRST_PSEUDO_REGISTER
; i
< max_regno
; i
++)
1188 if (basic_block_live_at_start
[0][i
/ REGSET_ELT_BITS
]
1189 & ((REGSET_ELT_TYPE
) 1 << (i
% REGSET_ELT_BITS
)))
1190 reg_basic_block
[i
] = REG_BLOCK_GLOBAL
;
1192 /* Now the life information is accurate.
1193 Make one more pass over each basic block
1194 to delete dead stores, create autoincrement addressing
1195 and record how many times each register is used, is set, or dies.
1197 To save time, we operate directly in basic_block_live_at_end[i],
1198 thus destroying it (in fact, converting it into a copy of
1199 basic_block_live_at_start[i]). This is ok now because
1200 basic_block_live_at_end[i] is no longer used past this point. */
1204 for (i
= 0; i
< n_basic_blocks
; i
++)
1206 propagate_block (basic_block_live_at_end
[i
],
1207 basic_block_head
[i
], basic_block_end
[i
], 1,
1215 /* Something live during a setjmp should not be put in a register
1216 on certain machines which restore regs from stack frames
1217 rather than from the jmpbuf.
1218 But we don't need to do this for the user's variables, since
1219 ANSI says only volatile variables need this. */
1220 #ifdef LONGJMP_RESTORE_FROM_STACK
1221 for (i
= FIRST_PSEUDO_REGISTER
; i
< nregs
; i
++)
1222 if (regs_live_at_setjmp
[i
/ REGSET_ELT_BITS
]
1223 & ((REGSET_ELT_TYPE
) 1 << (i
% REGSET_ELT_BITS
))
1224 && regno_reg_rtx
[i
] != 0 && ! REG_USERVAR_P (regno_reg_rtx
[i
]))
1226 reg_live_length
[i
] = -1;
1227 reg_basic_block
[i
] = -1;
1232 /* We have a problem with any pseudoreg that
1233 lives across the setjmp. ANSI says that if a
1234 user variable does not change in value
1235 between the setjmp and the longjmp, then the longjmp preserves it.
1236 This includes longjmp from a place where the pseudo appears dead.
1237 (In principle, the value still exists if it is in scope.)
1238 If the pseudo goes in a hard reg, some other value may occupy
1239 that hard reg where this pseudo is dead, thus clobbering the pseudo.
1240 Conclusion: such a pseudo must not go in a hard reg. */
1241 for (i
= FIRST_PSEUDO_REGISTER
; i
< nregs
; i
++)
1242 if ((regs_live_at_setjmp
[i
/ REGSET_ELT_BITS
]
1243 & ((REGSET_ELT_TYPE
) 1 << (i
% REGSET_ELT_BITS
)))
1244 && regno_reg_rtx
[i
] != 0)
1246 reg_live_length
[i
] = -1;
1247 reg_basic_block
[i
] = -1;
1250 obstack_free (&flow_obstack
, NULL_PTR
);
1253 /* Subroutines of life analysis. */
1255 /* Allocate the permanent data structures that represent the results
1256 of life analysis. Not static since used also for stupid life analysis. */
1259 allocate_for_life_analysis ()
1262 register regset tem
;
1264 regset_size
= ((max_regno
+ REGSET_ELT_BITS
- 1) / REGSET_ELT_BITS
);
1265 regset_bytes
= regset_size
* sizeof (*(regset
)0);
1267 reg_n_refs
= (int *) oballoc (max_regno
* sizeof (int));
1268 bzero ((char *) reg_n_refs
, max_regno
* sizeof (int));
1270 reg_n_sets
= (short *) oballoc (max_regno
* sizeof (short));
1271 bzero ((char *) reg_n_sets
, max_regno
* sizeof (short));
1273 reg_n_deaths
= (short *) oballoc (max_regno
* sizeof (short));
1274 bzero ((char *) reg_n_deaths
, max_regno
* sizeof (short));
1276 reg_changes_size
= (char *) oballoc (max_regno
* sizeof (char));
1277 bzero (reg_changes_size
, max_regno
* sizeof (char));;
1279 reg_live_length
= (int *) oballoc (max_regno
* sizeof (int));
1280 bzero ((char *) reg_live_length
, max_regno
* sizeof (int));
1282 reg_n_calls_crossed
= (int *) oballoc (max_regno
* sizeof (int));
1283 bzero ((char *) reg_n_calls_crossed
, max_regno
* sizeof (int));
1285 reg_basic_block
= (int *) oballoc (max_regno
* sizeof (int));
1286 for (i
= 0; i
< max_regno
; i
++)
1287 reg_basic_block
[i
] = REG_BLOCK_UNKNOWN
;
1289 basic_block_live_at_start
1290 = (regset
*) oballoc (n_basic_blocks
* sizeof (regset
));
1291 tem
= (regset
) oballoc (n_basic_blocks
* regset_bytes
);
1292 bzero ((char *) tem
, n_basic_blocks
* regset_bytes
);
1293 init_regset_vector (basic_block_live_at_start
, tem
,
1294 n_basic_blocks
, regset_bytes
);
1296 regs_live_at_setjmp
= (regset
) oballoc (regset_bytes
);
1297 bzero ((char *) regs_live_at_setjmp
, regset_bytes
);
1300 /* Make each element of VECTOR point at a regset,
1301 taking the space for all those regsets from SPACE.
1302 SPACE is of type regset, but it is really as long as NELTS regsets.
1303 BYTES_PER_ELT is the number of bytes in one regset. */
1306 init_regset_vector (vector
, space
, nelts
, bytes_per_elt
)
1313 register regset p
= space
;
1315 for (i
= 0; i
< nelts
; i
++)
1318 p
+= bytes_per_elt
/ sizeof (*p
);
1322 /* Compute the registers live at the beginning of a basic block
1323 from those live at the end.
1325 When called, OLD contains those live at the end.
1326 On return, it contains those live at the beginning.
1327 FIRST and LAST are the first and last insns of the basic block.
1329 FINAL is nonzero if we are doing the final pass which is not
1330 for computing the life info (since that has already been done)
1331 but for acting on it. On this pass, we delete dead stores,
1332 set up the logical links and dead-variables lists of instructions,
1333 and merge instructions for autoincrement and autodecrement addresses.
1335 SIGNIFICANT is nonzero only the first time for each basic block.
1336 If it is nonzero, it points to a regset in which we store
1337 a 1 for each register that is set within the block.
1339 BNUM is the number of the basic block. */
1342 propagate_block (old
, first
, last
, final
, significant
, bnum
)
1343 register regset old
;
1355 /* The following variables are used only if FINAL is nonzero. */
1356 /* This vector gets one element for each reg that has been live
1357 at any point in the basic block that has been scanned so far.
1358 SOMETIMES_MAX says how many elements are in use so far.
1359 In each element, OFFSET is the byte-number within a regset
1360 for the register described by the element, and BIT is a mask
1361 for that register's bit within the byte. */
1362 register struct sometimes
{ short offset
; short bit
; } *regs_sometimes_live
;
1363 int sometimes_max
= 0;
1364 /* This regset has 1 for each reg that we have seen live so far.
1365 It and REGS_SOMETIMES_LIVE are updated together. */
1368 /* The loop depth may change in the middle of a basic block. Since we
1369 scan from end to beginning, we start with the depth at the end of the
1370 current basic block, and adjust as we pass ends and starts of loops. */
1371 loop_depth
= basic_block_loop_depth
[bnum
];
1373 dead
= (regset
) alloca (regset_bytes
);
1374 live
= (regset
) alloca (regset_bytes
);
1379 /* Include any notes at the end of the block in the scan.
1380 This is in case the block ends with a call to setjmp. */
1382 while (NEXT_INSN (last
) != 0 && GET_CODE (NEXT_INSN (last
)) == NOTE
)
1384 /* Look for loop boundaries, we are going forward here. */
1385 last
= NEXT_INSN (last
);
1386 if (NOTE_LINE_NUMBER (last
) == NOTE_INSN_LOOP_BEG
)
1388 else if (NOTE_LINE_NUMBER (last
) == NOTE_INSN_LOOP_END
)
1394 register int i
, offset
;
1395 REGSET_ELT_TYPE bit
;
1398 maxlive
= (regset
) alloca (regset_bytes
);
1399 bcopy ((char *) old
, (char *) maxlive
, regset_bytes
);
1401 = (struct sometimes
*) alloca (max_regno
* sizeof (struct sometimes
));
1403 /* Process the regs live at the end of the block.
1404 Enter them in MAXLIVE and REGS_SOMETIMES_LIVE.
1405 Also mark them as not local to any one basic block. */
1407 for (offset
= 0, i
= 0; offset
< regset_size
; offset
++)
1408 for (bit
= 1; bit
; bit
<<= 1, i
++)
1412 if (old
[offset
] & bit
)
1414 reg_basic_block
[i
] = REG_BLOCK_GLOBAL
;
1415 regs_sometimes_live
[sometimes_max
].offset
= offset
;
1416 regs_sometimes_live
[sometimes_max
].bit
= i
% REGSET_ELT_BITS
;
1422 /* Scan the block an insn at a time from end to beginning. */
1424 for (insn
= last
; ; insn
= prev
)
1426 prev
= PREV_INSN (insn
);
1428 if (GET_CODE (insn
) == NOTE
)
1430 /* Look for loop boundaries, remembering that we are going
1432 if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_END
)
1434 else if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
)
1437 /* If we have LOOP_DEPTH == 0, there has been a bookkeeping error.
1438 Abort now rather than setting register status incorrectly. */
1439 if (loop_depth
== 0)
1442 /* If this is a call to `setjmp' et al,
1443 warn if any non-volatile datum is live. */
1445 if (final
&& NOTE_LINE_NUMBER (insn
) == NOTE_INSN_SETJMP
)
1448 for (i
= 0; i
< regset_size
; i
++)
1449 regs_live_at_setjmp
[i
] |= old
[i
];
1453 /* Update the life-status of regs for this insn.
1454 First DEAD gets which regs are set in this insn
1455 then LIVE gets which regs are used in this insn.
1456 Then the regs live before the insn
1457 are those live after, with DEAD regs turned off,
1458 and then LIVE regs turned on. */
1460 else if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i')
1463 rtx note
= find_reg_note (insn
, REG_RETVAL
, NULL_RTX
);
1465 = (insn_dead_p (PATTERN (insn
), old
, 0)
1466 /* Don't delete something that refers to volatile storage! */
1467 && ! INSN_VOLATILE (insn
));
1469 = (insn_is_dead
&& note
!= 0
1470 && libcall_dead_p (PATTERN (insn
), old
, note
, insn
));
1472 /* If an instruction consists of just dead store(s) on final pass,
1473 "delete" it by turning it into a NOTE of type NOTE_INSN_DELETED.
1474 We could really delete it with delete_insn, but that
1475 can cause trouble for first or last insn in a basic block. */
1476 if (final
&& insn_is_dead
)
1478 PUT_CODE (insn
, NOTE
);
1479 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
1480 NOTE_SOURCE_FILE (insn
) = 0;
1482 /* CC0 is now known to be dead. Either this insn used it,
1483 in which case it doesn't anymore, or clobbered it,
1484 so the next insn can't use it. */
1487 /* If this insn is copying the return value from a library call,
1488 delete the entire library call. */
1489 if (libcall_is_dead
)
1491 rtx first
= XEXP (note
, 0);
1493 while (INSN_DELETED_P (first
))
1494 first
= NEXT_INSN (first
);
1499 NOTE_LINE_NUMBER (p
) = NOTE_INSN_DELETED
;
1500 NOTE_SOURCE_FILE (p
) = 0;
1506 for (i
= 0; i
< regset_size
; i
++)
1508 dead
[i
] = 0; /* Faster than bzero here */
1509 live
[i
] = 0; /* since regset_size is usually small */
1512 /* See if this is an increment or decrement that can be
1513 merged into a following memory address. */
1516 register rtx x
= PATTERN (insn
);
1517 /* Does this instruction increment or decrement a register? */
1518 if (final
&& GET_CODE (x
) == SET
1519 && GET_CODE (SET_DEST (x
)) == REG
1520 && (GET_CODE (SET_SRC (x
)) == PLUS
1521 || GET_CODE (SET_SRC (x
)) == MINUS
)
1522 && XEXP (SET_SRC (x
), 0) == SET_DEST (x
)
1523 && GET_CODE (XEXP (SET_SRC (x
), 1)) == CONST_INT
1524 /* Ok, look for a following memory ref we can combine with.
1525 If one is found, change the memory ref to a PRE_INC
1526 or PRE_DEC, cancel this insn, and return 1.
1527 Return 0 if nothing has been done. */
1528 && try_pre_increment_1 (insn
))
1531 #endif /* AUTO_INC_DEC */
1533 /* If this is not the final pass, and this insn is copying the
1534 value of a library call and it's dead, don't scan the
1535 insns that perform the library call, so that the call's
1536 arguments are not marked live. */
1537 if (libcall_is_dead
)
1539 /* Mark the dest reg as `significant'. */
1540 mark_set_regs (old
, dead
, PATTERN (insn
), NULL_RTX
, significant
);
1542 insn
= XEXP (note
, 0);
1543 prev
= PREV_INSN (insn
);
1545 else if (GET_CODE (PATTERN (insn
)) == SET
1546 && SET_DEST (PATTERN (insn
)) == stack_pointer_rtx
1547 && GET_CODE (SET_SRC (PATTERN (insn
))) == PLUS
1548 && XEXP (SET_SRC (PATTERN (insn
)), 0) == stack_pointer_rtx
1549 && GET_CODE (XEXP (SET_SRC (PATTERN (insn
)), 1)) == CONST_INT
)
1550 /* We have an insn to pop a constant amount off the stack.
1551 (Such insns use PLUS regardless of the direction of the stack,
1552 and any insn to adjust the stack by a constant is always a pop.)
1553 These insns, if not dead stores, have no effect on life. */
1557 /* LIVE gets the regs used in INSN;
1558 DEAD gets those set by it. Dead insns don't make anything
1561 mark_set_regs (old
, dead
, PATTERN (insn
),
1562 final
? insn
: NULL_RTX
, significant
);
1564 /* If an insn doesn't use CC0, it becomes dead since we
1565 assume that every insn clobbers it. So show it dead here;
1566 mark_used_regs will set it live if it is referenced. */
1570 mark_used_regs (old
, live
, PATTERN (insn
), final
, insn
);
1572 /* Sometimes we may have inserted something before INSN (such as
1573 a move) when we make an auto-inc. So ensure we will scan
1576 prev
= PREV_INSN (insn
);
1579 if (! insn_is_dead
&& GET_CODE (insn
) == CALL_INSN
)
1585 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1587 note
= XEXP (note
, 1))
1588 if (GET_CODE (XEXP (note
, 0)) == USE
)
1589 mark_used_regs (old
, live
, SET_DEST (XEXP (note
, 0)),
1592 /* Each call clobbers all call-clobbered regs that are not
1593 global. Note that the function-value reg is a
1594 call-clobbered reg, and mark_set_regs has already had
1595 a chance to handle it. */
1597 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1598 if (call_used_regs
[i
] && ! global_regs
[i
])
1599 dead
[i
/ REGSET_ELT_BITS
]
1600 |= ((REGSET_ELT_TYPE
) 1 << (i
% REGSET_ELT_BITS
));
1602 /* The stack ptr is used (honorarily) by a CALL insn. */
1603 live
[STACK_POINTER_REGNUM
/ REGSET_ELT_BITS
]
1604 |= ((REGSET_ELT_TYPE
) 1
1605 << (STACK_POINTER_REGNUM
% REGSET_ELT_BITS
));
1607 /* Calls may also reference any of the global registers,
1608 so they are made live. */
1609 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1611 mark_used_regs (old
, live
,
1612 gen_rtx (REG
, reg_raw_mode
[i
], i
),
1615 /* Calls also clobber memory. */
1619 /* Update OLD for the registers used or set. */
1620 for (i
= 0; i
< regset_size
; i
++)
1626 if (GET_CODE (insn
) == CALL_INSN
&& final
)
1628 /* Any regs live at the time of a call instruction
1629 must not go in a register clobbered by calls.
1630 Find all regs now live and record this for them. */
1632 register struct sometimes
*p
= regs_sometimes_live
;
1634 for (i
= 0; i
< sometimes_max
; i
++, p
++)
1635 if (old
[p
->offset
] & ((REGSET_ELT_TYPE
) 1 << p
->bit
))
1636 reg_n_calls_crossed
[p
->offset
* REGSET_ELT_BITS
+ p
->bit
]+= 1;
1640 /* On final pass, add any additional sometimes-live regs
1641 into MAXLIVE and REGS_SOMETIMES_LIVE.
1642 Also update counts of how many insns each reg is live at. */
1646 for (i
= 0; i
< regset_size
; i
++)
1648 register REGSET_ELT_TYPE diff
= live
[i
] & ~maxlive
[i
];
1654 for (regno
= 0; diff
&& regno
< REGSET_ELT_BITS
; regno
++)
1655 if (diff
& ((REGSET_ELT_TYPE
) 1 << regno
))
1657 regs_sometimes_live
[sometimes_max
].offset
= i
;
1658 regs_sometimes_live
[sometimes_max
].bit
= regno
;
1659 diff
&= ~ ((REGSET_ELT_TYPE
) 1 << regno
);
1666 register struct sometimes
*p
= regs_sometimes_live
;
1667 for (i
= 0; i
< sometimes_max
; i
++, p
++)
1669 if (old
[p
->offset
] & ((REGSET_ELT_TYPE
) 1 << p
->bit
))
1670 reg_live_length
[p
->offset
* REGSET_ELT_BITS
+ p
->bit
]++;
1680 if (num_scratch
> max_scratch
)
1681 max_scratch
= num_scratch
;
1684 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
1685 (SET expressions whose destinations are registers dead after the insn).
1686 NEEDED is the regset that says which regs are alive after the insn.
1688 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL. */
1691 insn_dead_p (x
, needed
, call_ok
)
1696 register RTX_CODE code
= GET_CODE (x
);
1697 /* If setting something that's a reg or part of one,
1698 see if that register's altered value will be live. */
1702 register rtx r
= SET_DEST (x
);
1703 /* A SET that is a subroutine call cannot be dead. */
1704 if (! call_ok
&& GET_CODE (SET_SRC (x
)) == CALL
)
1708 if (GET_CODE (r
) == CC0
)
1712 if (GET_CODE (r
) == MEM
&& last_mem_set
&& ! MEM_VOLATILE_P (r
)
1713 && rtx_equal_p (r
, last_mem_set
))
1716 while (GET_CODE (r
) == SUBREG
1717 || GET_CODE (r
) == STRICT_LOW_PART
1718 || GET_CODE (r
) == ZERO_EXTRACT
1719 || GET_CODE (r
) == SIGN_EXTRACT
)
1722 if (GET_CODE (r
) == REG
)
1724 register int regno
= REGNO (r
);
1725 register int offset
= regno
/ REGSET_ELT_BITS
;
1726 register REGSET_ELT_TYPE bit
1727 = (REGSET_ELT_TYPE
) 1 << (regno
% REGSET_ELT_BITS
);
1729 /* Don't delete insns to set global regs. */
1730 if ((regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
1731 /* Make sure insns to set frame pointer aren't deleted. */
1732 || regno
== FRAME_POINTER_REGNUM
1733 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
1734 || regno
== HARD_FRAME_POINTER_REGNUM
1736 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1737 /* Make sure insns to set arg pointer are never deleted
1738 (if the arg pointer isn't fixed, there will be a USE for
1739 it, so we can treat it normally). */
1740 || (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
1742 || (needed
[offset
] & bit
) != 0)
1745 /* If this is a hard register, verify that subsequent words are
1747 if (regno
< FIRST_PSEUDO_REGISTER
)
1749 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (r
));
1752 if ((needed
[(regno
+ n
) / REGSET_ELT_BITS
]
1753 & ((REGSET_ELT_TYPE
) 1
1754 << ((regno
+ n
) % REGSET_ELT_BITS
))) != 0)
1761 /* If performing several activities,
1762 insn is dead if each activity is individually dead.
1763 Also, CLOBBERs and USEs can be ignored; a CLOBBER or USE
1764 that's inside a PARALLEL doesn't make the insn worth keeping. */
1765 else if (code
== PARALLEL
)
1767 register int i
= XVECLEN (x
, 0);
1768 for (i
--; i
>= 0; i
--)
1770 rtx elt
= XVECEXP (x
, 0, i
);
1771 if (!insn_dead_p (elt
, needed
, call_ok
)
1772 && GET_CODE (elt
) != CLOBBER
1773 && GET_CODE (elt
) != USE
)
1778 /* We do not check CLOBBER or USE here.
1779 An insn consisting of just a CLOBBER or just a USE
1780 should not be deleted. */
1784 /* If X is the pattern of the last insn in a libcall, and assuming X is dead,
1785 return 1 if the entire library call is dead.
1786 This is true if X copies a register (hard or pseudo)
1787 and if the hard return reg of the call insn is dead.
1788 (The caller should have tested the destination of X already for death.)
1790 If this insn doesn't just copy a register, then we don't
1791 have an ordinary libcall. In that case, cse could not have
1792 managed to substitute the source for the dest later on,
1793 so we can assume the libcall is dead.
1795 NEEDED is the bit vector of pseudoregs live before this insn.
1796 NOTE is the REG_RETVAL note of the insn. INSN is the insn itself. */
1799 libcall_dead_p (x
, needed
, note
, insn
)
1805 register RTX_CODE code
= GET_CODE (x
);
1809 register rtx r
= SET_SRC (x
);
1810 if (GET_CODE (r
) == REG
)
1812 rtx call
= XEXP (note
, 0);
1815 /* Find the call insn. */
1816 while (call
!= insn
&& GET_CODE (call
) != CALL_INSN
)
1817 call
= NEXT_INSN (call
);
1819 /* If there is none, do nothing special,
1820 since ordinary death handling can understand these insns. */
1824 /* See if the hard reg holding the value is dead.
1825 If this is a PARALLEL, find the call within it. */
1826 call
= PATTERN (call
);
1827 if (GET_CODE (call
) == PARALLEL
)
1829 for (i
= XVECLEN (call
, 0) - 1; i
>= 0; i
--)
1830 if (GET_CODE (XVECEXP (call
, 0, i
)) == SET
1831 && GET_CODE (SET_SRC (XVECEXP (call
, 0, i
))) == CALL
)
1834 /* This may be a library call that is returning a value
1835 via invisible pointer. Do nothing special, since
1836 ordinary death handling can understand these insns. */
1840 call
= XVECEXP (call
, 0, i
);
1843 return insn_dead_p (call
, needed
, 1);
1849 /* Return 1 if register REGNO was used before it was set.
1850 In other words, if it is live at function entry.
1851 Don't count global regster variables, though. */
1854 regno_uninitialized (regno
)
1857 if (n_basic_blocks
== 0
1858 || (regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
]))
1861 return (basic_block_live_at_start
[0][regno
/ REGSET_ELT_BITS
]
1862 & ((REGSET_ELT_TYPE
) 1 << (regno
% REGSET_ELT_BITS
)));
1865 /* 1 if register REGNO was alive at a place where `setjmp' was called
1866 and was set more than once or is an argument.
1867 Such regs may be clobbered by `longjmp'. */
1870 regno_clobbered_at_setjmp (regno
)
1873 if (n_basic_blocks
== 0)
1876 return ((reg_n_sets
[regno
] > 1
1877 || (basic_block_live_at_start
[0][regno
/ REGSET_ELT_BITS
]
1878 & ((REGSET_ELT_TYPE
) 1 << (regno
% REGSET_ELT_BITS
))))
1879 && (regs_live_at_setjmp
[regno
/ REGSET_ELT_BITS
]
1880 & ((REGSET_ELT_TYPE
) 1 << (regno
% REGSET_ELT_BITS
))));
1883 /* Process the registers that are set within X.
1884 Their bits are set to 1 in the regset DEAD,
1885 because they are dead prior to this insn.
1887 If INSN is nonzero, it is the insn being processed
1888 and the fact that it is nonzero implies this is the FINAL pass
1889 in propagate_block. In this case, various info about register
1890 usage is stored, LOG_LINKS fields of insns are set up. */
1893 mark_set_regs (needed
, dead
, x
, insn
, significant
)
1900 register RTX_CODE code
= GET_CODE (x
);
1902 if (code
== SET
|| code
== CLOBBER
)
1903 mark_set_1 (needed
, dead
, x
, insn
, significant
);
1904 else if (code
== PARALLEL
)
1907 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
1909 code
= GET_CODE (XVECEXP (x
, 0, i
));
1910 if (code
== SET
|| code
== CLOBBER
)
1911 mark_set_1 (needed
, dead
, XVECEXP (x
, 0, i
), insn
, significant
);
1916 /* Process a single SET rtx, X. */
1919 mark_set_1 (needed
, dead
, x
, insn
, significant
)
1927 register rtx reg
= SET_DEST (x
);
1929 /* Modifying just one hardware register of a multi-reg value
1930 or just a byte field of a register
1931 does not mean the value from before this insn is now dead.
1932 But it does mean liveness of that register at the end of the block
1935 Within mark_set_1, however, we treat it as if the register is
1936 indeed modified. mark_used_regs will, however, also treat this
1937 register as being used. Thus, we treat these insns as setting a
1938 new value for the register as a function of its old value. This
1939 cases LOG_LINKS to be made appropriately and this will help combine. */
1941 while (GET_CODE (reg
) == SUBREG
|| GET_CODE (reg
) == ZERO_EXTRACT
1942 || GET_CODE (reg
) == SIGN_EXTRACT
1943 || GET_CODE (reg
) == STRICT_LOW_PART
)
1944 reg
= XEXP (reg
, 0);
1946 /* If we are writing into memory or into a register mentioned in the
1947 address of the last thing stored into memory, show we don't know
1948 what the last store was. If we are writing memory, save the address
1949 unless it is volatile. */
1950 if (GET_CODE (reg
) == MEM
1951 || (GET_CODE (reg
) == REG
1952 && last_mem_set
!= 0 && reg_overlap_mentioned_p (reg
, last_mem_set
)))
1955 if (GET_CODE (reg
) == MEM
&& ! side_effects_p (reg
)
1956 /* There are no REG_INC notes for SP, so we can't assume we'll see
1957 everything that invalidates it. To be safe, don't eliminate any
1958 stores though SP; none of them should be redundant anyway. */
1959 && ! reg_mentioned_p (stack_pointer_rtx
, reg
))
1962 if (GET_CODE (reg
) == REG
1963 && (regno
= REGNO (reg
), regno
!= FRAME_POINTER_REGNUM
)
1964 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
1965 && regno
!= HARD_FRAME_POINTER_REGNUM
1967 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1968 && ! (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
1970 && ! (regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
]))
1971 /* && regno != STACK_POINTER_REGNUM) -- let's try without this. */
1973 register int offset
= regno
/ REGSET_ELT_BITS
;
1974 register REGSET_ELT_TYPE bit
1975 = (REGSET_ELT_TYPE
) 1 << (regno
% REGSET_ELT_BITS
);
1976 REGSET_ELT_TYPE all_needed
= (needed
[offset
] & bit
);
1977 REGSET_ELT_TYPE some_needed
= (needed
[offset
] & bit
);
1979 /* Mark it as a significant register for this basic block. */
1981 significant
[offset
] |= bit
;
1983 /* Mark it as as dead before this insn. */
1984 dead
[offset
] |= bit
;
1986 /* A hard reg in a wide mode may really be multiple registers.
1987 If so, mark all of them just like the first. */
1988 if (regno
< FIRST_PSEUDO_REGISTER
)
1992 /* Nothing below is needed for the stack pointer; get out asap.
1993 Eg, log links aren't needed, since combine won't use them. */
1994 if (regno
== STACK_POINTER_REGNUM
)
1997 n
= HARD_REGNO_NREGS (regno
, GET_MODE (reg
));
2001 significant
[(regno
+ n
) / REGSET_ELT_BITS
]
2002 |= (REGSET_ELT_TYPE
) 1 << ((regno
+ n
) % REGSET_ELT_BITS
);
2003 dead
[(regno
+ n
) / REGSET_ELT_BITS
]
2004 |= (REGSET_ELT_TYPE
) 1 << ((regno
+ n
) % REGSET_ELT_BITS
);
2006 |= (needed
[(regno
+ n
) / REGSET_ELT_BITS
]
2007 & (REGSET_ELT_TYPE
) 1 << ((regno
+ n
) % REGSET_ELT_BITS
));
2009 &= (needed
[(regno
+ n
) / REGSET_ELT_BITS
]
2010 & (REGSET_ELT_TYPE
) 1 << ((regno
+ n
) % REGSET_ELT_BITS
));
2013 /* Additional data to record if this is the final pass. */
2016 register rtx y
= reg_next_use
[regno
];
2017 register int blocknum
= BLOCK_NUM (insn
);
2019 /* If this is a hard reg, record this function uses the reg. */
2021 if (regno
< FIRST_PSEUDO_REGISTER
)
2024 int endregno
= regno
+ HARD_REGNO_NREGS (regno
, GET_MODE (reg
));
2026 for (i
= regno
; i
< endregno
; i
++)
2028 /* The next use is no longer "next", since a store
2030 reg_next_use
[i
] = 0;
2032 regs_ever_live
[i
] = 1;
2038 /* The next use is no longer "next", since a store
2040 reg_next_use
[regno
] = 0;
2042 /* Keep track of which basic blocks each reg appears in. */
2044 if (reg_basic_block
[regno
] == REG_BLOCK_UNKNOWN
)
2045 reg_basic_block
[regno
] = blocknum
;
2046 else if (reg_basic_block
[regno
] != blocknum
)
2047 reg_basic_block
[regno
] = REG_BLOCK_GLOBAL
;
2049 /* Count (weighted) references, stores, etc. This counts a
2050 register twice if it is modified, but that is correct. */
2051 reg_n_sets
[regno
]++;
2053 reg_n_refs
[regno
] += loop_depth
;
2055 /* The insns where a reg is live are normally counted
2056 elsewhere, but we want the count to include the insn
2057 where the reg is set, and the normal counting mechanism
2058 would not count it. */
2059 reg_live_length
[regno
]++;
2064 /* Make a logical link from the next following insn
2065 that uses this register, back to this insn.
2066 The following insns have already been processed.
2068 We don't build a LOG_LINK for hard registers containing
2069 in ASM_OPERANDs. If these registers get replaced,
2070 we might wind up changing the semantics of the insn,
2071 even if reload can make what appear to be valid assignments
2073 if (y
&& (BLOCK_NUM (y
) == blocknum
)
2074 && (regno
>= FIRST_PSEUDO_REGISTER
2075 || asm_noperands (PATTERN (y
)) < 0))
2077 = gen_rtx (INSN_LIST
, VOIDmode
, insn
, LOG_LINKS (y
));
2079 else if (! some_needed
)
2081 /* Note that dead stores have already been deleted when possible
2082 If we get here, we have found a dead store that cannot
2083 be eliminated (because the same insn does something useful).
2084 Indicate this by marking the reg being set as dying here. */
2086 = gen_rtx (EXPR_LIST
, REG_UNUSED
, reg
, REG_NOTES (insn
));
2087 reg_n_deaths
[REGNO (reg
)]++;
2091 /* This is a case where we have a multi-word hard register
2092 and some, but not all, of the words of the register are
2093 needed in subsequent insns. Write REG_UNUSED notes
2094 for those parts that were not needed. This case should
2099 for (i
= HARD_REGNO_NREGS (regno
, GET_MODE (reg
)) - 1;
2101 if ((needed
[(regno
+ i
) / REGSET_ELT_BITS
]
2102 & ((REGSET_ELT_TYPE
) 1
2103 << ((regno
+ i
) % REGSET_ELT_BITS
))) == 0)
2105 = gen_rtx (EXPR_LIST
, REG_UNUSED
,
2106 gen_rtx (REG
, reg_raw_mode
[regno
+ i
],
2112 else if (GET_CODE (reg
) == REG
)
2113 reg_next_use
[regno
] = 0;
2115 /* If this is the last pass and this is a SCRATCH, show it will be dying
2116 here and count it. */
2117 else if (GET_CODE (reg
) == SCRATCH
&& insn
!= 0)
2120 = gen_rtx (EXPR_LIST
, REG_UNUSED
, reg
, REG_NOTES (insn
));
2127 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
2131 find_auto_inc (needed
, x
, insn
)
2136 rtx addr
= XEXP (x
, 0);
2137 HOST_WIDE_INT offset
= 0;
2140 /* Here we detect use of an index register which might be good for
2141 postincrement, postdecrement, preincrement, or predecrement. */
2143 if (GET_CODE (addr
) == PLUS
&& GET_CODE (XEXP (addr
, 1)) == CONST_INT
)
2144 offset
= INTVAL (XEXP (addr
, 1)), addr
= XEXP (addr
, 0);
2146 if (GET_CODE (addr
) == REG
)
2149 register int size
= GET_MODE_SIZE (GET_MODE (x
));
2152 int regno
= REGNO (addr
);
2154 /* Is the next use an increment that might make auto-increment? */
2155 if ((incr
= reg_next_use
[regno
]) != 0
2156 && (set
= single_set (incr
)) != 0
2157 && GET_CODE (set
) == SET
2158 && BLOCK_NUM (incr
) == BLOCK_NUM (insn
)
2159 /* Can't add side effects to jumps; if reg is spilled and
2160 reloaded, there's no way to store back the altered value. */
2161 && GET_CODE (insn
) != JUMP_INSN
2162 && (y
= SET_SRC (set
), GET_CODE (y
) == PLUS
)
2163 && XEXP (y
, 0) == addr
2164 && GET_CODE (XEXP (y
, 1)) == CONST_INT
2166 #ifdef HAVE_POST_INCREMENT
2167 || (INTVAL (XEXP (y
, 1)) == size
&& offset
== 0)
2169 #ifdef HAVE_POST_DECREMENT
2170 || (INTVAL (XEXP (y
, 1)) == - size
&& offset
== 0)
2172 #ifdef HAVE_PRE_INCREMENT
2173 || (INTVAL (XEXP (y
, 1)) == size
&& offset
== size
)
2175 #ifdef HAVE_PRE_DECREMENT
2176 || (INTVAL (XEXP (y
, 1)) == - size
&& offset
== - size
)
2179 /* Make sure this reg appears only once in this insn. */
2180 && (use
= find_use_as_address (PATTERN (insn
), addr
, offset
),
2181 use
!= 0 && use
!= (rtx
) 1))
2183 rtx q
= SET_DEST (set
);
2184 enum rtx_code inc_code
= (INTVAL (XEXP (y
, 1)) == size
2185 ? (offset
? PRE_INC
: POST_INC
)
2186 : (offset
? PRE_DEC
: POST_DEC
));
2188 if (dead_or_set_p (incr
, addr
))
2190 /* This is the simple case. Try to make the auto-inc. If
2191 we can't, we are done. Otherwise, we will do any
2192 needed updates below. */
2193 if (! validate_change (insn
, &XEXP (x
, 0),
2194 gen_rtx (inc_code
, Pmode
, addr
),
2198 else if (GET_CODE (q
) == REG
2199 /* PREV_INSN used here to check the semi-open interval
2201 && ! reg_used_between_p (q
, PREV_INSN (insn
), incr
))
2203 /* We have *p followed sometime later by q = p+size.
2204 Both p and q must be live afterward,
2205 and q is not used between INSN and it's assignment.
2206 Change it to q = p, ...*q..., q = q+size.
2207 Then fall into the usual case. */
2211 emit_move_insn (q
, addr
);
2212 insns
= get_insns ();
2215 /* If anything in INSNS have UID's that don't fit within the
2216 extra space we allocate earlier, we can't make this auto-inc.
2217 This should never happen. */
2218 for (temp
= insns
; temp
; temp
= NEXT_INSN (temp
))
2220 if (INSN_UID (temp
) > max_uid_for_flow
)
2222 BLOCK_NUM (temp
) = BLOCK_NUM (insn
);
2225 /* If we can't make the auto-inc, or can't make the
2226 replacement into Y, exit. There's no point in making
2227 the change below if we can't do the auto-inc and doing
2228 so is not correct in the pre-inc case. */
2230 validate_change (insn
, &XEXP (x
, 0),
2231 gen_rtx (inc_code
, Pmode
, q
),
2233 validate_change (incr
, &XEXP (y
, 0), q
, 1);
2234 if (! apply_change_group ())
2237 /* We now know we'll be doing this change, so emit the
2238 new insn(s) and do the updates. */
2239 emit_insns_before (insns
, insn
);
2241 if (basic_block_head
[BLOCK_NUM (insn
)] == insn
)
2242 basic_block_head
[BLOCK_NUM (insn
)] = insns
;
2244 /* INCR will become a NOTE and INSN won't contain a
2245 use of ADDR. If a use of ADDR was just placed in
2246 the insn before INSN, make that the next use.
2247 Otherwise, invalidate it. */
2248 if (GET_CODE (PREV_INSN (insn
)) == INSN
2249 && GET_CODE (PATTERN (PREV_INSN (insn
))) == SET
2250 && SET_SRC (PATTERN (PREV_INSN (insn
))) == addr
)
2251 reg_next_use
[regno
] = PREV_INSN (insn
);
2253 reg_next_use
[regno
] = 0;
2258 /* REGNO is now used in INCR which is below INSN, but
2259 it previously wasn't live here. If we don't mark
2260 it as needed, we'll put a REG_DEAD note for it
2261 on this insn, which is incorrect. */
2262 needed
[regno
/ REGSET_ELT_BITS
]
2263 |= (REGSET_ELT_TYPE
) 1 << (regno
% REGSET_ELT_BITS
);
2265 /* If there are any calls between INSN and INCR, show
2266 that REGNO now crosses them. */
2267 for (temp
= insn
; temp
!= incr
; temp
= NEXT_INSN (temp
))
2268 if (GET_CODE (temp
) == CALL_INSN
)
2269 reg_n_calls_crossed
[regno
]++;
2274 /* If we haven't returned, it means we were able to make the
2275 auto-inc, so update the status. First, record that this insn
2276 has an implicit side effect. */
2279 = gen_rtx (EXPR_LIST
, REG_INC
, addr
, REG_NOTES (insn
));
2281 /* Modify the old increment-insn to simply copy
2282 the already-incremented value of our register. */
2283 if (! validate_change (incr
, &SET_SRC (set
), addr
, 0))
2286 /* If that makes it a no-op (copying the register into itself) delete
2287 it so it won't appear to be a "use" and a "set" of this
2289 if (SET_DEST (set
) == addr
)
2291 PUT_CODE (incr
, NOTE
);
2292 NOTE_LINE_NUMBER (incr
) = NOTE_INSN_DELETED
;
2293 NOTE_SOURCE_FILE (incr
) = 0;
2296 if (regno
>= FIRST_PSEUDO_REGISTER
)
2298 /* Count an extra reference to the reg. When a reg is
2299 incremented, spilling it is worse, so we want to make
2300 that less likely. */
2301 reg_n_refs
[regno
] += loop_depth
;
2303 /* Count the increment as a setting of the register,
2304 even though it isn't a SET in rtl. */
2305 reg_n_sets
[regno
]++;
2310 #endif /* AUTO_INC_DEC */
2312 /* Scan expression X and store a 1-bit in LIVE for each reg it uses.
2313 This is done assuming the registers needed from X
2314 are those that have 1-bits in NEEDED.
2316 On the final pass, FINAL is 1. This means try for autoincrement
2317 and count the uses and deaths of each pseudo-reg.
2319 INSN is the containing instruction. If INSN is dead, this function is not
2323 mark_used_regs (needed
, live
, x
, final
, insn
)
2330 register RTX_CODE code
;
2335 code
= GET_CODE (x
);
2356 /* If we are clobbering a MEM, mark any registers inside the address
2358 if (GET_CODE (XEXP (x
, 0)) == MEM
)
2359 mark_used_regs (needed
, live
, XEXP (XEXP (x
, 0), 0), final
, insn
);
2363 /* Invalidate the data for the last MEM stored. We could do this only
2364 if the addresses conflict, but this doesn't seem worthwhile. */
2369 find_auto_inc (needed
, x
, insn
);
2374 if (GET_CODE (SUBREG_REG (x
)) == REG
2375 && REGNO (SUBREG_REG (x
)) >= FIRST_PSEUDO_REGISTER
2376 && (GET_MODE_SIZE (GET_MODE (x
))
2377 != GET_MODE_SIZE (GET_MODE (SUBREG_REG (x
))))
2378 && (INTEGRAL_MODE_P (GET_MODE (x
))
2379 || INTEGRAL_MODE_P (GET_MODE (SUBREG_REG (x
)))))
2380 reg_changes_size
[REGNO (SUBREG_REG (x
))] = 1;
2382 /* While we're here, optimize this case. */
2385 /* ... fall through ... */
2388 /* See a register other than being set
2389 => mark it as needed. */
2393 register int offset
= regno
/ REGSET_ELT_BITS
;
2394 register REGSET_ELT_TYPE bit
2395 = (REGSET_ELT_TYPE
) 1 << (regno
% REGSET_ELT_BITS
);
2396 REGSET_ELT_TYPE all_needed
= needed
[offset
] & bit
;
2397 REGSET_ELT_TYPE some_needed
= needed
[offset
] & bit
;
2399 live
[offset
] |= bit
;
2400 /* A hard reg in a wide mode may really be multiple registers.
2401 If so, mark all of them just like the first. */
2402 if (regno
< FIRST_PSEUDO_REGISTER
)
2406 /* For stack ptr or fixed arg pointer,
2407 nothing below can be necessary, so waste no more time. */
2408 if (regno
== STACK_POINTER_REGNUM
2409 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2410 || regno
== HARD_FRAME_POINTER_REGNUM
2412 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2413 || (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
2415 || regno
== FRAME_POINTER_REGNUM
)
2417 /* If this is a register we are going to try to eliminate,
2418 don't mark it live here. If we are successful in
2419 eliminating it, it need not be live unless it is used for
2420 pseudos, in which case it will have been set live when
2421 it was allocated to the pseudos. If the register will not
2422 be eliminated, reload will set it live at that point. */
2424 if (! TEST_HARD_REG_BIT (elim_reg_set
, regno
))
2425 regs_ever_live
[regno
] = 1;
2428 /* No death notes for global register variables;
2429 their values are live after this function exits. */
2430 if (global_regs
[regno
])
2433 reg_next_use
[regno
] = insn
;
2437 n
= HARD_REGNO_NREGS (regno
, GET_MODE (x
));
2440 live
[(regno
+ n
) / REGSET_ELT_BITS
]
2441 |= (REGSET_ELT_TYPE
) 1 << ((regno
+ n
) % REGSET_ELT_BITS
);
2443 |= (needed
[(regno
+ n
) / REGSET_ELT_BITS
]
2444 & (REGSET_ELT_TYPE
) 1 << ((regno
+ n
) % REGSET_ELT_BITS
));
2446 &= (needed
[(regno
+ n
) / REGSET_ELT_BITS
]
2447 & (REGSET_ELT_TYPE
) 1 << ((regno
+ n
) % REGSET_ELT_BITS
));
2452 /* Record where each reg is used, so when the reg
2453 is set we know the next insn that uses it. */
2455 reg_next_use
[regno
] = insn
;
2457 if (regno
< FIRST_PSEUDO_REGISTER
)
2459 /* If a hard reg is being used,
2460 record that this function does use it. */
2462 i
= HARD_REGNO_NREGS (regno
, GET_MODE (x
));
2466 regs_ever_live
[regno
+ --i
] = 1;
2471 /* Keep track of which basic block each reg appears in. */
2473 register int blocknum
= BLOCK_NUM (insn
);
2475 if (reg_basic_block
[regno
] == REG_BLOCK_UNKNOWN
)
2476 reg_basic_block
[regno
] = blocknum
;
2477 else if (reg_basic_block
[regno
] != blocknum
)
2478 reg_basic_block
[regno
] = REG_BLOCK_GLOBAL
;
2480 /* Count (weighted) number of uses of each reg. */
2482 reg_n_refs
[regno
] += loop_depth
;
2485 /* Record and count the insns in which a reg dies.
2486 If it is used in this insn and was dead below the insn
2487 then it dies in this insn. If it was set in this insn,
2488 we do not make a REG_DEAD note; likewise if we already
2489 made such a note. */
2492 && ! dead_or_set_p (insn
, x
)
2494 && (regno
>= FIRST_PSEUDO_REGISTER
|| ! fixed_regs
[regno
])
2498 /* Check for the case where the register dying partially
2499 overlaps the register set by this insn. */
2500 if (regno
< FIRST_PSEUDO_REGISTER
2501 && HARD_REGNO_NREGS (regno
, GET_MODE (x
)) > 1)
2503 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (x
));
2505 some_needed
|= dead_or_set_regno_p (insn
, regno
+ n
);
2508 /* If none of the words in X is needed, make a REG_DEAD
2509 note. Otherwise, we must make partial REG_DEAD notes. */
2513 = gen_rtx (EXPR_LIST
, REG_DEAD
, x
, REG_NOTES (insn
));
2514 reg_n_deaths
[regno
]++;
2520 /* Don't make a REG_DEAD note for a part of a register
2521 that is set in the insn. */
2523 for (i
= HARD_REGNO_NREGS (regno
, GET_MODE (x
)) - 1;
2525 if ((needed
[(regno
+ i
) / REGSET_ELT_BITS
]
2526 & ((REGSET_ELT_TYPE
) 1
2527 << ((regno
+ i
) % REGSET_ELT_BITS
))) == 0
2528 && ! dead_or_set_regno_p (insn
, regno
+ i
))
2530 = gen_rtx (EXPR_LIST
, REG_DEAD
,
2531 gen_rtx (REG
, reg_raw_mode
[regno
+ i
],
2542 register rtx testreg
= SET_DEST (x
);
2545 /* If storing into MEM, don't show it as being used. But do
2546 show the address as being used. */
2547 if (GET_CODE (testreg
) == MEM
)
2551 find_auto_inc (needed
, testreg
, insn
);
2553 mark_used_regs (needed
, live
, XEXP (testreg
, 0), final
, insn
);
2554 mark_used_regs (needed
, live
, SET_SRC (x
), final
, insn
);
2558 /* Storing in STRICT_LOW_PART is like storing in a reg
2559 in that this SET might be dead, so ignore it in TESTREG.
2560 but in some other ways it is like using the reg.
2562 Storing in a SUBREG or a bit field is like storing the entire
2563 register in that if the register's value is not used
2564 then this SET is not needed. */
2565 while (GET_CODE (testreg
) == STRICT_LOW_PART
2566 || GET_CODE (testreg
) == ZERO_EXTRACT
2567 || GET_CODE (testreg
) == SIGN_EXTRACT
2568 || GET_CODE (testreg
) == SUBREG
)
2570 /* Modifying a single register in an alternate mode
2571 does not use any of the old value. But these other
2572 ways of storing in a register do use the old value. */
2573 if (GET_CODE (testreg
) == SUBREG
2574 && !(REG_SIZE (SUBREG_REG (testreg
)) > REG_SIZE (testreg
)))
2579 testreg
= XEXP (testreg
, 0);
2582 /* If this is a store into a register,
2583 recursively scan the value being stored. */
2585 if (GET_CODE (testreg
) == REG
2586 && (regno
= REGNO (testreg
), regno
!= FRAME_POINTER_REGNUM
)
2587 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2588 && regno
!= HARD_FRAME_POINTER_REGNUM
2590 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2591 && ! (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
2594 /* We used to exclude global_regs here, but that seems wrong.
2595 Storing in them is like storing in mem. */
2597 mark_used_regs (needed
, live
, SET_SRC (x
), final
, insn
);
2599 mark_used_regs (needed
, live
, SET_DEST (x
), final
, insn
);
2606 /* If exiting needs the right stack value, consider this insn as
2607 using the stack pointer. In any event, consider it as using
2608 all global registers. */
2610 #ifdef EXIT_IGNORE_STACK
2611 if (! EXIT_IGNORE_STACK
2612 || (! FRAME_POINTER_REQUIRED
&& flag_omit_frame_pointer
))
2614 live
[STACK_POINTER_REGNUM
/ REGSET_ELT_BITS
]
2615 |= (REGSET_ELT_TYPE
) 1 << (STACK_POINTER_REGNUM
% REGSET_ELT_BITS
);
2617 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
2619 live
[i
/ REGSET_ELT_BITS
]
2620 |= (REGSET_ELT_TYPE
) 1 << (i
% REGSET_ELT_BITS
);
2624 /* Recursively scan the operands of this expression. */
2627 register char *fmt
= GET_RTX_FORMAT (code
);
2630 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
2634 /* Tail recursive case: save a function call level. */
2640 mark_used_regs (needed
, live
, XEXP (x
, i
), final
, insn
);
2642 else if (fmt
[i
] == 'E')
2645 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
2646 mark_used_regs (needed
, live
, XVECEXP (x
, i
, j
), final
, insn
);
2655 try_pre_increment_1 (insn
)
2658 /* Find the next use of this reg. If in same basic block,
2659 make it do pre-increment or pre-decrement if appropriate. */
2660 rtx x
= PATTERN (insn
);
2661 HOST_WIDE_INT amount
= ((GET_CODE (SET_SRC (x
)) == PLUS
? 1 : -1)
2662 * INTVAL (XEXP (SET_SRC (x
), 1)));
2663 int regno
= REGNO (SET_DEST (x
));
2664 rtx y
= reg_next_use
[regno
];
2666 && BLOCK_NUM (y
) == BLOCK_NUM (insn
)
2667 /* Don't do this if the reg dies, or gets set in y; a standard addressing
2668 mode would be better. */
2669 && ! dead_or_set_p (y
, SET_DEST (x
))
2670 && try_pre_increment (y
, SET_DEST (PATTERN (insn
)),
2673 /* We have found a suitable auto-increment
2674 and already changed insn Y to do it.
2675 So flush this increment-instruction. */
2676 PUT_CODE (insn
, NOTE
);
2677 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
2678 NOTE_SOURCE_FILE (insn
) = 0;
2679 /* Count a reference to this reg for the increment
2680 insn we are deleting. When a reg is incremented.
2681 spilling it is worse, so we want to make that
2683 if (regno
>= FIRST_PSEUDO_REGISTER
)
2685 reg_n_refs
[regno
] += loop_depth
;
2686 reg_n_sets
[regno
]++;
2693 /* Try to change INSN so that it does pre-increment or pre-decrement
2694 addressing on register REG in order to add AMOUNT to REG.
2695 AMOUNT is negative for pre-decrement.
2696 Returns 1 if the change could be made.
2697 This checks all about the validity of the result of modifying INSN. */
2700 try_pre_increment (insn
, reg
, amount
)
2702 HOST_WIDE_INT amount
;
2706 /* Nonzero if we can try to make a pre-increment or pre-decrement.
2707 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
2709 /* Nonzero if we can try to make a post-increment or post-decrement.
2710 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
2711 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
2712 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
2715 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
2718 /* From the sign of increment, see which possibilities are conceivable
2719 on this target machine. */
2720 #ifdef HAVE_PRE_INCREMENT
2724 #ifdef HAVE_POST_INCREMENT
2729 #ifdef HAVE_PRE_DECREMENT
2733 #ifdef HAVE_POST_DECREMENT
2738 if (! (pre_ok
|| post_ok
))
2741 /* It is not safe to add a side effect to a jump insn
2742 because if the incremented register is spilled and must be reloaded
2743 there would be no way to store the incremented value back in memory. */
2745 if (GET_CODE (insn
) == JUMP_INSN
)
2750 use
= find_use_as_address (PATTERN (insn
), reg
, 0);
2751 if (post_ok
&& (use
== 0 || use
== (rtx
) 1))
2753 use
= find_use_as_address (PATTERN (insn
), reg
, -amount
);
2757 if (use
== 0 || use
== (rtx
) 1)
2760 if (GET_MODE_SIZE (GET_MODE (use
)) != (amount
> 0 ? amount
: - amount
))
2763 /* See if this combination of instruction and addressing mode exists. */
2764 if (! validate_change (insn
, &XEXP (use
, 0),
2766 ? (do_post
? POST_INC
: PRE_INC
)
2767 : (do_post
? POST_DEC
: PRE_DEC
),
2771 /* Record that this insn now has an implicit side effect on X. */
2772 REG_NOTES (insn
) = gen_rtx (EXPR_LIST
, REG_INC
, reg
, REG_NOTES (insn
));
2776 #endif /* AUTO_INC_DEC */
2778 /* Find the place in the rtx X where REG is used as a memory address.
2779 Return the MEM rtx that so uses it.
2780 If PLUSCONST is nonzero, search instead for a memory address equivalent to
2781 (plus REG (const_int PLUSCONST)).
2783 If such an address does not appear, return 0.
2784 If REG appears more than once, or is used other than in such an address,
2788 find_use_as_address (x
, reg
, plusconst
)
2791 HOST_WIDE_INT plusconst
;
2793 enum rtx_code code
= GET_CODE (x
);
2794 char *fmt
= GET_RTX_FORMAT (code
);
2796 register rtx value
= 0;
2799 if (code
== MEM
&& XEXP (x
, 0) == reg
&& plusconst
== 0)
2802 if (code
== MEM
&& GET_CODE (XEXP (x
, 0)) == PLUS
2803 && XEXP (XEXP (x
, 0), 0) == reg
2804 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
2805 && INTVAL (XEXP (XEXP (x
, 0), 1)) == plusconst
)
2808 if (code
== SIGN_EXTRACT
|| code
== ZERO_EXTRACT
)
2810 /* If REG occurs inside a MEM used in a bit-field reference,
2811 that is unacceptable. */
2812 if (find_use_as_address (XEXP (x
, 0), reg
, 0) != 0)
2813 return (rtx
) (HOST_WIDE_INT
) 1;
2817 return (rtx
) (HOST_WIDE_INT
) 1;
2819 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
2823 tem
= find_use_as_address (XEXP (x
, i
), reg
, plusconst
);
2827 return (rtx
) (HOST_WIDE_INT
) 1;
2832 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
2834 tem
= find_use_as_address (XVECEXP (x
, i
, j
), reg
, plusconst
);
2838 return (rtx
) (HOST_WIDE_INT
) 1;
2846 /* Write information about registers and basic blocks into FILE.
2847 This is part of making a debugging dump. */
2850 dump_flow_info (file
)
2854 static char *reg_class_names
[] = REG_CLASS_NAMES
;
2856 fprintf (file
, "%d registers.\n", max_regno
);
2858 for (i
= FIRST_PSEUDO_REGISTER
; i
< max_regno
; i
++)
2861 enum reg_class
class, altclass
;
2862 fprintf (file
, "\nRegister %d used %d times across %d insns",
2863 i
, reg_n_refs
[i
], reg_live_length
[i
]);
2864 if (reg_basic_block
[i
] >= 0)
2865 fprintf (file
, " in block %d", reg_basic_block
[i
]);
2866 if (reg_n_deaths
[i
] != 1)
2867 fprintf (file
, "; dies in %d places", reg_n_deaths
[i
]);
2868 if (reg_n_calls_crossed
[i
] == 1)
2869 fprintf (file
, "; crosses 1 call");
2870 else if (reg_n_calls_crossed
[i
])
2871 fprintf (file
, "; crosses %d calls", reg_n_calls_crossed
[i
]);
2872 if (PSEUDO_REGNO_BYTES (i
) != UNITS_PER_WORD
)
2873 fprintf (file
, "; %d bytes", PSEUDO_REGNO_BYTES (i
));
2874 class = reg_preferred_class (i
);
2875 altclass
= reg_alternate_class (i
);
2876 if (class != GENERAL_REGS
|| altclass
!= ALL_REGS
)
2878 if (altclass
== ALL_REGS
|| class == ALL_REGS
)
2879 fprintf (file
, "; pref %s", reg_class_names
[(int) class]);
2880 else if (altclass
== NO_REGS
)
2881 fprintf (file
, "; %s or none", reg_class_names
[(int) class]);
2883 fprintf (file
, "; pref %s, else %s",
2884 reg_class_names
[(int) class],
2885 reg_class_names
[(int) altclass
]);
2887 if (REGNO_POINTER_FLAG (i
))
2888 fprintf (file
, "; pointer");
2889 fprintf (file
, ".\n");
2891 fprintf (file
, "\n%d basic blocks.\n", n_basic_blocks
);
2892 for (i
= 0; i
< n_basic_blocks
; i
++)
2894 register rtx head
, jump
;
2896 fprintf (file
, "\nBasic block %d: first insn %d, last %d.\n",
2898 INSN_UID (basic_block_head
[i
]),
2899 INSN_UID (basic_block_end
[i
]));
2900 /* The control flow graph's storage is freed
2901 now when flow_analysis returns.
2902 Don't try to print it if it is gone. */
2903 if (basic_block_drops_in
)
2905 fprintf (file
, "Reached from blocks: ");
2906 head
= basic_block_head
[i
];
2907 if (GET_CODE (head
) == CODE_LABEL
)
2908 for (jump
= LABEL_REFS (head
);
2910 jump
= LABEL_NEXTREF (jump
))
2912 register int from_block
= BLOCK_NUM (CONTAINING_INSN (jump
));
2913 fprintf (file
, " %d", from_block
);
2915 if (basic_block_drops_in
[i
])
2916 fprintf (file
, " previous");
2918 fprintf (file
, "\nRegisters live at start:");
2919 for (regno
= 0; regno
< max_regno
; regno
++)
2921 register int offset
= regno
/ REGSET_ELT_BITS
;
2922 register REGSET_ELT_TYPE bit
2923 = (REGSET_ELT_TYPE
) 1 << (regno
% REGSET_ELT_BITS
);
2924 if (basic_block_live_at_start
[i
][offset
] & bit
)
2925 fprintf (file
, " %d", regno
);
2927 fprintf (file
, "\n");
2929 fprintf (file
, "\n");