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1.1 root 1: /* Data flow analysis for GNU compiler.
2: Copyright (C) 1987, 1988, 1992 Free Software Foundation, Inc.
3:
4: This file is part of GNU CC.
5:
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)
9: any later version.
10:
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.
15:
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. */
19:
20:
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.
25:
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.
29:
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.
33:
34: ** find_basic_blocks **
35:
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.
40:
41: find_basic_blocks also finds any unreachable loops
42: and deletes them.
43:
44: ** life_analysis **
45:
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.
49:
50: ** live-register info **
51:
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.
54:
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
58: of the basic block.
59:
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).
66:
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
76: REG_DEAD notes.
77:
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.
84:
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.
88:
89: ** Other actions of life_analysis **
90:
91: life_analysis sets up the LOG_LINKS fields of insns because the
92: information needed to do so is readily available.
93:
94: life_analysis deletes insns whose only effect is to store a value
95: that is never used.
96:
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.
102:
103: Each time an incrementing or decrementing address is created,
104: a REG_INC element is added to the insn's REG_NOTES list.
105:
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. */
109:
110: #include <stdio.h>
111: #include "config.h"
112: #include "rtl.h"
113: #include "basic-block.h"
114: #include "insn-config.h"
115: #include "regs.h"
116: #include "hard-reg-set.h"
117: #include "flags.h"
118: #include "output.h"
119:
120: #include "obstack.h"
121: #define obstack_chunk_alloc xmalloc
122: #define obstack_chunk_free free
123:
124: extern int xmalloc ();
125: extern void free ();
126:
127: /* List of labels that must never be deleted. */
128: extern rtx forced_labels;
129:
130: /* Get the basic block number of an insn.
131: This info should not be expected to remain available
132: after the end of life_analysis. */
133:
134: /* This is the limit of the allocated space in the following two arrays. */
135:
136: static int max_uid_for_flow;
137:
138: #define BLOCK_NUM(INSN) uid_block_number[INSN_UID (INSN)]
139:
140: /* This is where the BLOCK_NUM values are really stored.
141: This is set up by find_basic_blocks and used there and in life_analysis,
142: and then freed. */
143:
144: static short *uid_block_number;
145:
146: /* INSN_VOLATILE (insn) is 1 if the insn refers to anything volatile. */
147:
148: #define INSN_VOLATILE(INSN) uid_volatile[INSN_UID (INSN)]
149: static char *uid_volatile;
150:
151: /* Number of basic blocks in the current function. */
152:
153: int n_basic_blocks;
154:
155: /* Maximum register number used in this function, plus one. */
156:
157: int max_regno;
158:
159: /* Maximum number of SCRATCH rtx's used in any basic block of this function. */
160:
161: int max_scratch;
162:
163: /* Number of SCRATCH rtx's in the current block. */
164:
165: static int num_scratch;
166:
167: /* Indexed by n, gives number of basic block that (REG n) is used in.
168: If the value is REG_BLOCK_GLOBAL (-2),
169: it means (REG n) is used in more than one basic block.
170: REG_BLOCK_UNKNOWN (-1) means it hasn't been seen yet so we don't know.
171: This information remains valid for the rest of the compilation
172: of the current function; it is used to control register allocation. */
173:
174: short *reg_basic_block;
175:
176: /* Indexed by n, gives number of times (REG n) is used or set, each
177: weighted by its loop-depth.
178: This information remains valid for the rest of the compilation
179: of the current function; it is used to control register allocation. */
180:
181: int *reg_n_refs;
182:
183: /* Indexed by N, gives number of places register N dies.
184: This information remains valid for the rest of the compilation
185: of the current function; it is used to control register allocation. */
186:
187: short *reg_n_deaths;
188:
189: /* Indexed by N, gives 1 if that reg is live across any CALL_INSNs.
190: This information remains valid for the rest of the compilation
191: of the current function; it is used to control register allocation. */
192:
193: int *reg_n_calls_crossed;
194:
195: /* Total number of instructions at which (REG n) is live.
196: The larger this is, the less priority (REG n) gets for
197: allocation in a real register.
198: This information remains valid for the rest of the compilation
199: of the current function; it is used to control register allocation.
200:
201: local-alloc.c may alter this number to change the priority.
202:
203: Negative values are special.
204: -1 is used to mark a pseudo reg which has a constant or memory equivalent
205: and is used infrequently enough that it should not get a hard register.
206: -2 is used to mark a pseudo reg for a parameter, when a frame pointer
207: is not required. global-alloc.c makes an allocno for this but does
208: not try to assign a hard register to it. */
209:
210: int *reg_live_length;
211:
212: /* Element N is the next insn that uses (hard or pseudo) register number N
213: within the current basic block; or zero, if there is no such insn.
214: This is valid only during the final backward scan in propagate_block. */
215:
216: static rtx *reg_next_use;
217:
218: /* Size of a regset for the current function,
219: in (1) bytes and (2) elements. */
220:
221: int regset_bytes;
222: int regset_size;
223:
224: /* Element N is first insn in basic block N.
225: This info lasts until we finish compiling the function. */
226:
227: rtx *basic_block_head;
228:
229: /* Element N is last insn in basic block N.
230: This info lasts until we finish compiling the function. */
231:
232: rtx *basic_block_end;
233:
234: /* Element N is a regset describing the registers live
235: at the start of basic block N.
236: This info lasts until we finish compiling the function. */
237:
238: regset *basic_block_live_at_start;
239:
240: /* Regset of regs live when calls to `setjmp'-like functions happen. */
241:
242: regset regs_live_at_setjmp;
243:
244: /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
245: that have to go in the same hard reg.
246: The first two regs in the list are a pair, and the next two
247: are another pair, etc. */
248: rtx regs_may_share;
249:
250: /* Element N is nonzero if control can drop into basic block N
251: from the preceding basic block. Freed after life_analysis. */
252:
253: static char *basic_block_drops_in;
254:
255: /* Element N is depth within loops of the last insn in basic block number N.
256: Freed after life_analysis. */
257:
258: static short *basic_block_loop_depth;
259:
260: /* Element N nonzero if basic block N can actually be reached.
261: Vector exists only during find_basic_blocks. */
262:
263: static char *block_live_static;
264:
265: /* Depth within loops of basic block being scanned for lifetime analysis,
266: plus one. This is the weight attached to references to registers. */
267:
268: static int loop_depth;
269:
270: /* During propagate_block, this is non-zero if the value of CC0 is live. */
271:
272: static int cc0_live;
273:
274: /* During propagate_block, this contains the last MEM stored into. It
275: is used to eliminate consecutive stores to the same location. */
276:
277: static rtx last_mem_set;
278:
279: /* Set of registers that may be eliminable. These are handled specially
280: in updating regs_ever_live. */
281:
282: static HARD_REG_SET elim_reg_set;
283:
284: /* Forward declarations */
285: static void find_basic_blocks ();
286: static void life_analysis ();
287: static void mark_label_ref ();
288: void allocate_for_life_analysis (); /* Used also in stupid_life_analysis */
289: static void init_regset_vector ();
290: static void propagate_block ();
291: static void mark_set_regs ();
292: static void mark_used_regs ();
293: static int insn_dead_p ();
294: static int libcall_dead_p ();
295: static int try_pre_increment ();
296: static int try_pre_increment_1 ();
297: static rtx find_use_as_address ();
298: void dump_flow_info ();
299:
300: /* Find basic blocks of the current function and perform data flow analysis.
301: F is the first insn of the function and NREGS the number of register numbers
302: in use. */
303:
304: void
305: flow_analysis (f, nregs, file)
306: rtx f;
307: int nregs;
308: FILE *file;
309: {
310: register rtx insn;
311: register int i;
312: rtx nonlocal_label_list = nonlocal_label_rtx_list ();
313:
314: #ifdef ELIMINABLE_REGS
315: static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
316: #endif
317:
318: /* Record which registers will be eliminated. We use this in
319: mark_used_regs. */
320:
321: CLEAR_HARD_REG_SET (elim_reg_set);
322:
323: #ifdef ELIMINABLE_REGS
324: for (i = 0; i < sizeof eliminables / sizeof eliminables[0]; i++)
325: SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
326: #else
327: SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
328: #endif
329:
330: /* Count the basic blocks. Also find maximum insn uid value used. */
331:
332: {
333: register RTX_CODE prev_code = JUMP_INSN;
334: register RTX_CODE code;
335:
336: max_uid_for_flow = 0;
337:
338: for (insn = f, i = 0; insn; insn = NEXT_INSN (insn))
339: {
340: code = GET_CODE (insn);
341: if (INSN_UID (insn) > max_uid_for_flow)
342: max_uid_for_flow = INSN_UID (insn);
343: if (code == CODE_LABEL
344: || (GET_RTX_CLASS (code) == 'i'
345: && (prev_code == JUMP_INSN
346: || (prev_code == CALL_INSN
347: && nonlocal_label_list != 0)
348: || prev_code == BARRIER)))
349: i++;
350: if (code != NOTE)
351: prev_code = code;
352: }
353: }
354:
355: #ifdef AUTO_INC_DEC
356: /* Leave space for insns we make in some cases for auto-inc. These cases
357: are rare, so we don't need too much space. */
358: max_uid_for_flow += max_uid_for_flow / 10;
359: #endif
360:
361: /* Allocate some tables that last till end of compiling this function
362: and some needed only in find_basic_blocks and life_analysis. */
363:
364: n_basic_blocks = i;
365: basic_block_head = (rtx *) oballoc (n_basic_blocks * sizeof (rtx));
366: basic_block_end = (rtx *) oballoc (n_basic_blocks * sizeof (rtx));
367: basic_block_drops_in = (char *) alloca (n_basic_blocks);
368: basic_block_loop_depth = (short *) alloca (n_basic_blocks * sizeof (short));
369: uid_block_number
370: = (short *) alloca ((max_uid_for_flow + 1) * sizeof (short));
371: uid_volatile = (char *) alloca (max_uid_for_flow + 1);
372: bzero (uid_volatile, max_uid_for_flow + 1);
373:
374: find_basic_blocks (f, nonlocal_label_list);
375: life_analysis (f, nregs);
376: if (file)
377: dump_flow_info (file);
378:
379: basic_block_drops_in = 0;
380: uid_block_number = 0;
381: basic_block_loop_depth = 0;
382: }
383:
384: /* Find all basic blocks of the function whose first insn is F.
385: Store the correct data in the tables that describe the basic blocks,
386: set up the chains of references for each CODE_LABEL, and
387: delete any entire basic blocks that cannot be reached.
388:
389: NONLOCAL_LABEL_LIST is the same local variable from flow_analysis. */
390:
391: static void
392: find_basic_blocks (f, nonlocal_label_list)
393: rtx f, nonlocal_label_list;
394: {
395: register rtx insn;
396: register int i;
397: register char *block_live = (char *) alloca (n_basic_blocks);
398: register char *block_marked = (char *) alloca (n_basic_blocks);
399: /* List of label_refs to all labels whose addresses are taken
400: and used as data. */
401: rtx label_value_list = 0;
402:
403: block_live_static = block_live;
404: bzero (block_live, n_basic_blocks);
405: bzero (block_marked, n_basic_blocks);
406:
407: /* Initialize with just block 0 reachable and no blocks marked. */
408: if (n_basic_blocks > 0)
409: block_live[0] = 1;
410:
411: /* Initialize the ref chain of each label to 0. */
412: /* Record where all the blocks start and end and their depth in loops. */
413: /* For each insn, record the block it is in. */
414: /* Also mark as reachable any blocks headed by labels that
415: must not be deleted. */
416:
417: {
418: register RTX_CODE prev_code = JUMP_INSN;
419: register RTX_CODE code;
420: int depth = 1;
421:
422: for (insn = f, i = -1; insn; insn = NEXT_INSN (insn))
423: {
424: code = GET_CODE (insn);
425: if (code == NOTE)
426: {
427: if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
428: depth++;
429: else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
430: depth--;
431: }
432: /* A basic block starts at label, or after something that can jump. */
433: else if (code == CODE_LABEL
434: || (GET_RTX_CLASS (code) == 'i'
435: && (prev_code == JUMP_INSN
436: || (prev_code == CALL_INSN
437: && nonlocal_label_list != 0)
438: || prev_code == BARRIER)))
439: {
440: basic_block_head[++i] = insn;
441: basic_block_end[i] = insn;
442: basic_block_loop_depth[i] = depth;
443: if (code == CODE_LABEL)
444: {
445: LABEL_REFS (insn) = insn;
446: /* Any label that cannot be deleted
447: is considered to start a reachable block. */
448: if (LABEL_PRESERVE_P (insn))
449: block_live[i] = 1;
450: }
451: }
452: else if (GET_RTX_CLASS (code) == 'i')
453: {
454: basic_block_end[i] = insn;
455: basic_block_loop_depth[i] = depth;
456: }
457:
458: /* Make a list of all labels referred to other than by jumps. */
459: if (code == INSN || code == CALL_INSN)
460: {
461: rtx note = find_reg_note (insn, REG_LABEL, 0);
462: if (note != 0)
463: label_value_list = gen_rtx (EXPR_LIST, VOIDmode, XEXP (note, 0),
464: label_value_list);
465: }
466:
467: BLOCK_NUM (insn) = i;
468:
469: /* Don't separare a CALL_INSN from following CLOBBER insns. This is
470: a kludge that will go away when each CALL_INSN records its
471: USE and CLOBBERs. */
472:
473: if (code != NOTE
474: && ! (prev_code == CALL_INSN && code == INSN
475: && GET_CODE (PATTERN (insn)) == CLOBBER))
476: prev_code = code;
477: }
478: if (i + 1 != n_basic_blocks)
479: abort ();
480: }
481:
482: /* Don't delete the labels that are referenced by non-jump instructions. */
483: {
484: register rtx x;
485: for (x = label_value_list; x; x = XEXP (x, 1))
486: block_live[BLOCK_NUM (XEXP (x, 0))] = 1;
487: }
488:
489: /* Record which basic blocks control can drop in to. */
490:
491: {
492: register int i;
493: for (i = 0; i < n_basic_blocks; i++)
494: {
495: register rtx insn = PREV_INSN (basic_block_head[i]);
496: /* TEMP1 is used to avoid a bug in Sequent's compiler. */
497: register int temp1;
498: while (insn && GET_CODE (insn) == NOTE)
499: insn = PREV_INSN (insn);
500: temp1 = insn && GET_CODE (insn) != BARRIER;
501: basic_block_drops_in[i] = temp1;
502: }
503: }
504:
505: /* Now find which basic blocks can actually be reached
506: and put all jump insns' LABEL_REFS onto the ref-chains
507: of their target labels. */
508:
509: if (n_basic_blocks > 0)
510: {
511: int something_marked = 1;
512:
513: /* Find all indirect jump insns and mark them as possibly jumping
514: to all the labels whose addresses are explicitly used.
515: This is because, when there are computed gotos,
516: we can't tell which labels they jump to, of all the possibilities. */
517:
518: for (insn = f; insn; insn = NEXT_INSN (insn))
519: if (GET_CODE (insn) == JUMP_INSN
520: && GET_CODE (PATTERN (insn)) == SET
521: && SET_DEST (PATTERN (insn)) == pc_rtx
522: && GET_CODE (SET_SRC (PATTERN (insn))) == REG)
523: {
524: rtx x;
525: for (x = label_value_list; x; x = XEXP (x, 1))
526: mark_label_ref (gen_rtx (LABEL_REF, VOIDmode, XEXP (x, 0)),
527: insn, 0);
528: for (x = forced_labels; x; x = XEXP (x, 1))
529: mark_label_ref (gen_rtx (LABEL_REF, VOIDmode, XEXP (x, 0)),
530: insn, 0);
531: }
532:
533: /* Find all call insns and mark them as possibly jumping
534: to all the nonlocal goto handler labels. */
535:
536: for (insn = f; insn; insn = NEXT_INSN (insn))
537: if (GET_CODE (insn) == CALL_INSN)
538: {
539: rtx x;
540: for (x = nonlocal_label_list; x; x = XEXP (x, 1))
541: mark_label_ref (gen_rtx (LABEL_REF, VOIDmode, XEXP (x, 0)),
542: insn, 0);
543: /* ??? This could be made smarter:
544: in some cases it's possible to tell that certain
545: calls will not do a nonlocal goto.
546:
547: For example, if the nested functions that do the
548: nonlocal gotos do not have their addresses taken, then
549: only calls to those functions or to other nested
550: functions that use them could possibly do nonlocal
551: gotos. */
552: }
553:
554: /* Pass over all blocks, marking each block that is reachable
555: and has not yet been marked.
556: Keep doing this until, in one pass, no blocks have been marked.
557: Then blocks_live and blocks_marked are identical and correct.
558: In addition, all jumps actually reachable have been marked. */
559:
560: while (something_marked)
561: {
562: something_marked = 0;
563: for (i = 0; i < n_basic_blocks; i++)
564: if (block_live[i] && !block_marked[i])
565: {
566: block_marked[i] = 1;
567: something_marked = 1;
568: if (i + 1 < n_basic_blocks && basic_block_drops_in[i + 1])
569: block_live[i + 1] = 1;
570: insn = basic_block_end[i];
571: if (GET_CODE (insn) == JUMP_INSN)
572: mark_label_ref (PATTERN (insn), insn, 0);
573: }
574: }
575:
576: /* Now delete the code for any basic blocks that can't be reached.
577: They can occur because jump_optimize does not recognize
578: unreachable loops as unreachable. */
579:
580: for (i = 0; i < n_basic_blocks; i++)
581: if (!block_live[i])
582: {
583: insn = basic_block_head[i];
584: while (1)
585: {
586: if (GET_CODE (insn) == BARRIER)
587: abort ();
588: if (GET_CODE (insn) != NOTE)
589: {
590: PUT_CODE (insn, NOTE);
591: NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
592: NOTE_SOURCE_FILE (insn) = 0;
593: }
594: if (insn == basic_block_end[i])
595: {
596: /* BARRIERs are between basic blocks, not part of one.
597: Delete a BARRIER if the preceding jump is deleted.
598: We cannot alter a BARRIER into a NOTE
599: because it is too short; but we can really delete
600: it because it is not part of a basic block. */
601: if (NEXT_INSN (insn) != 0
602: && GET_CODE (NEXT_INSN (insn)) == BARRIER)
603: delete_insn (NEXT_INSN (insn));
604: break;
605: }
606: insn = NEXT_INSN (insn);
607: }
608: /* Each time we delete some basic blocks,
609: see if there is a jump around them that is
610: being turned into a no-op. If so, delete it. */
611:
612: if (block_live[i - 1])
613: {
614: register int j;
615: for (j = i; j < n_basic_blocks; j++)
616: if (block_live[j])
617: {
618: rtx label;
619: insn = basic_block_end[i - 1];
620: if (GET_CODE (insn) == JUMP_INSN
621: /* An unconditional jump is the only possibility
622: we must check for, since a conditional one
623: would make these blocks live. */
624: && simplejump_p (insn)
625: && (label = XEXP (SET_SRC (PATTERN (insn)), 0), 1)
626: && INSN_UID (label) != 0
627: && BLOCK_NUM (label) == j)
628: {
629: PUT_CODE (insn, NOTE);
630: NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
631: NOTE_SOURCE_FILE (insn) = 0;
632: if (GET_CODE (NEXT_INSN (insn)) != BARRIER)
633: abort ();
634: delete_insn (NEXT_INSN (insn));
635: }
636: break;
637: }
638: }
639: }
640: }
641: }
642:
643: /* Check expression X for label references;
644: if one is found, add INSN to the label's chain of references.
645:
646: CHECKDUP means check for and avoid creating duplicate references
647: from the same insn. Such duplicates do no serious harm but
648: can slow life analysis. CHECKDUP is set only when duplicates
649: are likely. */
650:
651: static void
652: mark_label_ref (x, insn, checkdup)
653: rtx x, insn;
654: int checkdup;
655: {
656: register RTX_CODE code;
657: register int i;
658: register char *fmt;
659:
660: /* We can be called with NULL when scanning label_value_list. */
661: if (x == 0)
662: return;
663:
664: code = GET_CODE (x);
665: if (code == LABEL_REF)
666: {
667: register rtx label = XEXP (x, 0);
668: register rtx y;
669: if (GET_CODE (label) != CODE_LABEL)
670: abort ();
671: /* If the label was never emitted, this insn is junk,
672: but avoid a crash trying to refer to BLOCK_NUM (label).
673: This can happen as a result of a syntax error
674: and a diagnostic has already been printed. */
675: if (INSN_UID (label) == 0)
676: return;
677: CONTAINING_INSN (x) = insn;
678: /* if CHECKDUP is set, check for duplicate ref from same insn
679: and don't insert. */
680: if (checkdup)
681: for (y = LABEL_REFS (label); y != label; y = LABEL_NEXTREF (y))
682: if (CONTAINING_INSN (y) == insn)
683: return;
684: LABEL_NEXTREF (x) = LABEL_REFS (label);
685: LABEL_REFS (label) = x;
686: block_live_static[BLOCK_NUM (label)] = 1;
687: return;
688: }
689:
690: fmt = GET_RTX_FORMAT (code);
691: for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
692: {
693: if (fmt[i] == 'e')
694: mark_label_ref (XEXP (x, i), insn, 0);
695: if (fmt[i] == 'E')
696: {
697: register int j;
698: for (j = 0; j < XVECLEN (x, i); j++)
699: mark_label_ref (XVECEXP (x, i, j), insn, 1);
700: }
701: }
702: }
703:
704: /* Determine which registers are live at the start of each
705: basic block of the function whose first insn is F.
706: NREGS is the number of registers used in F.
707: We allocate the vector basic_block_live_at_start
708: and the regsets that it points to, and fill them with the data.
709: regset_size and regset_bytes are also set here. */
710:
711: static void
712: life_analysis (f, nregs)
713: rtx f;
714: int nregs;
715: {
716: register regset tem;
717: int first_pass;
718: int changed;
719: /* For each basic block, a bitmask of regs
720: live on exit from the block. */
721: regset *basic_block_live_at_end;
722: /* For each basic block, a bitmask of regs
723: live on entry to a successor-block of this block.
724: If this does not match basic_block_live_at_end,
725: that must be updated, and the block must be rescanned. */
726: regset *basic_block_new_live_at_end;
727: /* For each basic block, a bitmask of regs
728: whose liveness at the end of the basic block
729: can make a difference in which regs are live on entry to the block.
730: These are the regs that are set within the basic block,
731: possibly excluding those that are used after they are set. */
732: regset *basic_block_significant;
733: register int i;
734: rtx insn;
735:
736: struct obstack flow_obstack;
737:
738: gcc_obstack_init (&flow_obstack);
739:
740: max_regno = nregs;
741:
742: bzero (regs_ever_live, sizeof regs_ever_live);
743:
744: /* Allocate and zero out many data structures
745: that will record the data from lifetime analysis. */
746:
747: allocate_for_life_analysis ();
748:
749: reg_next_use = (rtx *) alloca (nregs * sizeof (rtx));
750: bzero (reg_next_use, nregs * sizeof (rtx));
751:
752: /* Set up several regset-vectors used internally within this function.
753: Their meanings are documented above, with their declarations. */
754:
755: basic_block_live_at_end = (regset *) alloca (n_basic_blocks * sizeof (regset));
756: /* Don't use alloca since that leads to a crash rather than an error message
757: if there isn't enough space.
758: Don't use oballoc since we may need to allocate other things during
759: this function on the temporary obstack. */
760: tem = (regset) obstack_alloc (&flow_obstack, n_basic_blocks * regset_bytes);
761: bzero (tem, n_basic_blocks * regset_bytes);
762: init_regset_vector (basic_block_live_at_end, tem, n_basic_blocks, regset_bytes);
763:
764: basic_block_new_live_at_end = (regset *) alloca (n_basic_blocks * sizeof (regset));
765: tem = (regset) obstack_alloc (&flow_obstack, n_basic_blocks * regset_bytes);
766: bzero (tem, n_basic_blocks * regset_bytes);
767: init_regset_vector (basic_block_new_live_at_end, tem, n_basic_blocks, regset_bytes);
768:
769: basic_block_significant = (regset *) alloca (n_basic_blocks * sizeof (regset));
770: tem = (regset) obstack_alloc (&flow_obstack, n_basic_blocks * regset_bytes);
771: bzero (tem, n_basic_blocks * regset_bytes);
772: init_regset_vector (basic_block_significant, tem, n_basic_blocks, regset_bytes);
773:
774: /* Record which insns refer to any volatile memory
775: or for any reason can't be deleted just because they are dead stores.
776: Also, delete any insns that copy a register to itself. */
777:
778: for (insn = f; insn; insn = NEXT_INSN (insn))
779: {
780: enum rtx_code code1 = GET_CODE (insn);
781: if (code1 == CALL_INSN)
782: INSN_VOLATILE (insn) = 1;
783: else if (code1 == INSN || code1 == JUMP_INSN)
784: {
785: /* Delete (in effect) any obvious no-op moves. */
786: if (GET_CODE (PATTERN (insn)) == SET
787: && GET_CODE (SET_DEST (PATTERN (insn))) == REG
788: && GET_CODE (SET_SRC (PATTERN (insn))) == REG
789: && REGNO (SET_DEST (PATTERN (insn))) ==
790: REGNO (SET_SRC (PATTERN (insn)))
791: /* Insns carrying these notes are useful later on. */
792: && ! find_reg_note (insn, REG_EQUAL, 0))
793: {
794: PUT_CODE (insn, NOTE);
795: NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
796: NOTE_SOURCE_FILE (insn) = 0;
797: }
798: else if (GET_CODE (PATTERN (insn)) == PARALLEL)
799: {
800: /* If nothing but SETs of registers to themselves,
801: this insn can also be deleted. */
802: for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++)
803: {
804: rtx tem = XVECEXP (PATTERN (insn), 0, i);
805:
806: if (GET_CODE (tem) == USE
807: || GET_CODE (tem) == CLOBBER)
808: continue;
809:
810: if (GET_CODE (tem) != SET
811: || GET_CODE (SET_DEST (tem)) != REG
812: || GET_CODE (SET_SRC (tem)) != REG
813: || REGNO (SET_DEST (tem)) != REGNO (SET_SRC (tem)))
814: break;
815: }
816:
817: if (i == XVECLEN (PATTERN (insn), 0)
818: /* Insns carrying these notes are useful later on. */
819: && ! find_reg_note (insn, REG_EQUAL, 0))
820: {
821: PUT_CODE (insn, NOTE);
822: NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
823: NOTE_SOURCE_FILE (insn) = 0;
824: }
825: else
826: INSN_VOLATILE (insn) = volatile_refs_p (PATTERN (insn));
827: }
828: else if (GET_CODE (PATTERN (insn)) != USE)
829: INSN_VOLATILE (insn) = volatile_refs_p (PATTERN (insn));
830: /* A SET that makes space on the stack cannot be dead.
831: (Such SETs occur only for allocating variable-size data,
832: so they will always have a PLUS or MINUS according to the
833: direction of stack growth.)
834: Even if this function never uses this stack pointer value,
835: signal handlers do! */
836: else if (code1 == INSN && GET_CODE (PATTERN (insn)) == SET
837: && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
838: #ifdef STACK_GROWS_DOWNWARD
839: && GET_CODE (SET_SRC (PATTERN (insn))) == MINUS
840: #else
841: && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
842: #endif
843: && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx)
844: INSN_VOLATILE (insn) = 1;
845: }
846: }
847:
848: if (n_basic_blocks > 0)
849: #ifdef EXIT_IGNORE_STACK
850: if (! EXIT_IGNORE_STACK
851: || (! FRAME_POINTER_REQUIRED && flag_omit_frame_pointer))
852: #endif
853: {
854: /* If exiting needs the right stack value,
855: consider the stack pointer live at the end of the function. */
856: basic_block_live_at_end[n_basic_blocks - 1]
857: [STACK_POINTER_REGNUM / REGSET_ELT_BITS]
858: |= 1 << (STACK_POINTER_REGNUM % REGSET_ELT_BITS);
859: basic_block_new_live_at_end[n_basic_blocks - 1]
860: [STACK_POINTER_REGNUM / REGSET_ELT_BITS]
861: |= 1 << (STACK_POINTER_REGNUM % REGSET_ELT_BITS);
862: }
863:
864: /* Mark all global registers as being live at the end of the function
865: since they may be referenced by our caller. */
866:
867: if (n_basic_blocks > 0)
868: for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
869: if (global_regs[i])
870: {
871: basic_block_live_at_end[n_basic_blocks - 1]
872: [i / REGSET_ELT_BITS] |= 1 << (i % REGSET_ELT_BITS);
873: basic_block_new_live_at_end[n_basic_blocks - 1]
874: [i / REGSET_ELT_BITS] |= 1 << (i % REGSET_ELT_BITS);
875: }
876:
877: /* Propagate life info through the basic blocks
878: around the graph of basic blocks.
879:
880: This is a relaxation process: each time a new register
881: is live at the end of the basic block, we must scan the block
882: to determine which registers are, as a consequence, live at the beginning
883: of that block. These registers must then be marked live at the ends
884: of all the blocks that can transfer control to that block.
885: The process continues until it reaches a fixed point. */
886:
887: first_pass = 1;
888: changed = 1;
889: while (changed)
890: {
891: changed = 0;
892: for (i = n_basic_blocks - 1; i >= 0; i--)
893: {
894: int consider = first_pass;
895: int must_rescan = first_pass;
896: register int j;
897:
898: if (!first_pass)
899: {
900: /* Set CONSIDER if this block needs thinking about at all
901: (that is, if the regs live now at the end of it
902: are not the same as were live at the end of it when
903: we last thought about it).
904: Set must_rescan if it needs to be thought about
905: instruction by instruction (that is, if any additional
906: reg that is live at the end now but was not live there before
907: is one of the significant regs of this basic block). */
908:
909: for (j = 0; j < regset_size; j++)
910: {
911: register int x = (basic_block_new_live_at_end[i][j]
912: & ~basic_block_live_at_end[i][j]);
913: if (x)
914: consider = 1;
915: if (x & basic_block_significant[i][j])
916: {
917: must_rescan = 1;
918: consider = 1;
919: break;
920: }
921: }
922:
923: if (! consider)
924: continue;
925: }
926:
927: /* The live_at_start of this block may be changing,
928: so another pass will be required after this one. */
929: changed = 1;
930:
931: if (! must_rescan)
932: {
933: /* No complete rescan needed;
934: just record those variables newly known live at end
935: as live at start as well. */
936: for (j = 0; j < regset_size; j++)
937: {
938: register int x = basic_block_new_live_at_end[i][j]
939: & ~basic_block_live_at_end[i][j];
940: basic_block_live_at_start[i][j] |= x;
941: basic_block_live_at_end[i][j] |= x;
942: }
943: }
944: else
945: {
946: /* Update the basic_block_live_at_start
947: by propagation backwards through the block. */
948: bcopy (basic_block_new_live_at_end[i],
949: basic_block_live_at_end[i], regset_bytes);
950: bcopy (basic_block_live_at_end[i],
951: basic_block_live_at_start[i], regset_bytes);
952: propagate_block (basic_block_live_at_start[i],
953: basic_block_head[i], basic_block_end[i], 0,
954: first_pass ? basic_block_significant[i] : 0,
955: i);
956: }
957:
958: {
959: register rtx jump, head;
960: /* Update the basic_block_new_live_at_end's of the block
961: that falls through into this one (if any). */
962: head = basic_block_head[i];
963: jump = PREV_INSN (head);
964: if (basic_block_drops_in[i])
965: {
966: register int from_block = BLOCK_NUM (jump);
967: register int j;
968: for (j = 0; j < regset_size; j++)
969: basic_block_new_live_at_end[from_block][j]
970: |= basic_block_live_at_start[i][j];
971: }
972: /* Update the basic_block_new_live_at_end's of
973: all the blocks that jump to this one. */
974: if (GET_CODE (head) == CODE_LABEL)
975: for (jump = LABEL_REFS (head);
976: jump != head;
977: jump = LABEL_NEXTREF (jump))
978: {
979: register int from_block = BLOCK_NUM (CONTAINING_INSN (jump));
980: register int j;
981: for (j = 0; j < regset_size; j++)
982: basic_block_new_live_at_end[from_block][j]
983: |= basic_block_live_at_start[i][j];
984: }
985: }
986: #ifdef USE_C_ALLOCA
987: alloca (0);
988: #endif
989: }
990: first_pass = 0;
991: }
992:
993: /* The only pseudos that are live at the beginning of the function are
994: those that were not set anywhere in the function. local-alloc doesn't
995: know how to handle these correctly, so mark them as not local to any
996: one basic block. */
997:
998: if (n_basic_blocks > 0)
999: for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
1000: if (basic_block_live_at_start[0][i / REGSET_ELT_BITS]
1001: & (1 << (i % REGSET_ELT_BITS)))
1002: reg_basic_block[i] = REG_BLOCK_GLOBAL;
1003:
1004: /* Now the life information is accurate.
1005: Make one more pass over each basic block
1006: to delete dead stores, create autoincrement addressing
1007: and record how many times each register is used, is set, or dies.
1008:
1009: To save time, we operate directly in basic_block_live_at_end[i],
1010: thus destroying it (in fact, converting it into a copy of
1011: basic_block_live_at_start[i]). This is ok now because
1012: basic_block_live_at_end[i] is no longer used past this point. */
1013:
1014: max_scratch = 0;
1015:
1016: for (i = 0; i < n_basic_blocks; i++)
1017: {
1018: propagate_block (basic_block_live_at_end[i],
1019: basic_block_head[i], basic_block_end[i], 1, 0, i);
1020: #ifdef USE_C_ALLOCA
1021: alloca (0);
1022: #endif
1023: }
1024:
1025: #if 0
1026: /* Something live during a setjmp should not be put in a register
1027: on certain machines which restore regs from stack frames
1028: rather than from the jmpbuf.
1029: But we don't need to do this for the user's variables, since
1030: ANSI says only volatile variables need this. */
1031: #ifdef LONGJMP_RESTORE_FROM_STACK
1032: for (i = FIRST_PSEUDO_REGISTER; i < nregs; i++)
1033: if (regs_live_at_setjmp[i / REGSET_ELT_BITS] & (1 << (i % REGSET_ELT_BITS))
1034: && regno_reg_rtx[i] != 0 && ! REG_USERVAR_P (regno_reg_rtx[i]))
1035: {
1036: reg_live_length[i] = -1;
1037: reg_basic_block[i] = -1;
1038: }
1039: #endif
1040: #endif
1041:
1042: /* We have a problem with any pseudoreg that
1043: lives across the setjmp. ANSI says that if a
1044: user variable does not change in value
1045: between the setjmp and the longjmp, then the longjmp preserves it.
1046: This includes longjmp from a place where the pseudo appears dead.
1047: (In principle, the value still exists if it is in scope.)
1048: If the pseudo goes in a hard reg, some other value may occupy
1049: that hard reg where this pseudo is dead, thus clobbering the pseudo.
1050: Conclusion: such a pseudo must not go in a hard reg. */
1051: for (i = FIRST_PSEUDO_REGISTER; i < nregs; i++)
1052: if (regs_live_at_setjmp[i / REGSET_ELT_BITS] & (1 << (i % REGSET_ELT_BITS))
1053: && regno_reg_rtx[i] != 0)
1054: {
1055: reg_live_length[i] = -1;
1056: reg_basic_block[i] = -1;
1057: }
1058:
1059: obstack_free (&flow_obstack, 0);
1060: }
1061:
1062: /* Subroutines of life analysis. */
1063:
1064: /* Allocate the permanent data structures that represent the results
1065: of life analysis. Not static since used also for stupid life analysis. */
1066:
1067: void
1068: allocate_for_life_analysis ()
1069: {
1070: register int i;
1071: register regset tem;
1072:
1073: regset_size = ((max_regno + REGSET_ELT_BITS - 1) / REGSET_ELT_BITS);
1074: regset_bytes = regset_size * sizeof (*(regset)0);
1075:
1076: reg_n_refs = (int *) oballoc (max_regno * sizeof (int));
1077: bzero (reg_n_refs, max_regno * sizeof (int));
1078:
1079: reg_n_sets = (short *) oballoc (max_regno * sizeof (short));
1080: bzero (reg_n_sets, max_regno * sizeof (short));
1081:
1082: reg_n_deaths = (short *) oballoc (max_regno * sizeof (short));
1083: bzero (reg_n_deaths, max_regno * sizeof (short));
1084:
1085: reg_live_length = (int *) oballoc (max_regno * sizeof (int));
1086: bzero (reg_live_length, max_regno * sizeof (int));
1087:
1088: reg_n_calls_crossed = (int *) oballoc (max_regno * sizeof (int));
1089: bzero (reg_n_calls_crossed, max_regno * sizeof (int));
1090:
1091: reg_basic_block = (short *) oballoc (max_regno * sizeof (short));
1092: for (i = 0; i < max_regno; i++)
1093: reg_basic_block[i] = REG_BLOCK_UNKNOWN;
1094:
1095: basic_block_live_at_start = (regset *) oballoc (n_basic_blocks * sizeof (regset));
1096: tem = (regset) oballoc (n_basic_blocks * regset_bytes);
1097: bzero (tem, n_basic_blocks * regset_bytes);
1098: init_regset_vector (basic_block_live_at_start, tem, n_basic_blocks, regset_bytes);
1099:
1100: regs_live_at_setjmp = (regset) oballoc (regset_bytes);
1101: bzero (regs_live_at_setjmp, regset_bytes);
1102: }
1103:
1104: /* Make each element of VECTOR point at a regset,
1105: taking the space for all those regsets from SPACE.
1106: SPACE is of type regset, but it is really as long as NELTS regsets.
1107: BYTES_PER_ELT is the number of bytes in one regset. */
1108:
1109: static void
1110: init_regset_vector (vector, space, nelts, bytes_per_elt)
1111: regset *vector;
1112: regset space;
1113: int nelts;
1114: int bytes_per_elt;
1115: {
1116: register int i;
1117: register regset p = space;
1118:
1119: for (i = 0; i < nelts; i++)
1120: {
1121: vector[i] = p;
1122: p += bytes_per_elt / sizeof (*p);
1123: }
1124: }
1125:
1126: /* Compute the registers live at the beginning of a basic block
1127: from those live at the end.
1128:
1129: When called, OLD contains those live at the end.
1130: On return, it contains those live at the beginning.
1131: FIRST and LAST are the first and last insns of the basic block.
1132:
1133: FINAL is nonzero if we are doing the final pass which is not
1134: for computing the life info (since that has already been done)
1135: but for acting on it. On this pass, we delete dead stores,
1136: set up the logical links and dead-variables lists of instructions,
1137: and merge instructions for autoincrement and autodecrement addresses.
1138:
1139: SIGNIFICANT is nonzero only the first time for each basic block.
1140: If it is nonzero, it points to a regset in which we store
1141: a 1 for each register that is set within the block.
1142:
1143: BNUM is the number of the basic block. */
1144:
1145: static void
1146: propagate_block (old, first, last, final, significant, bnum)
1147: register regset old;
1148: rtx first;
1149: rtx last;
1150: int final;
1151: regset significant;
1152: int bnum;
1153: {
1154: register rtx insn;
1155: rtx prev;
1156: regset live;
1157: regset dead;
1158:
1159: /* The following variables are used only if FINAL is nonzero. */
1160: /* This vector gets one element for each reg that has been live
1161: at any point in the basic block that has been scanned so far.
1162: SOMETIMES_MAX says how many elements are in use so far.
1163: In each element, OFFSET is the byte-number within a regset
1164: for the register described by the element, and BIT is a mask
1165: for that register's bit within the byte. */
1166: register struct foo { short offset; short bit; } *regs_sometimes_live;
1167: int sometimes_max = 0;
1168: /* This regset has 1 for each reg that we have seen live so far.
1169: It and REGS_SOMETIMES_LIVE are updated together. */
1170: regset maxlive;
1171:
1172: /* The loop depth may change in the middle of a basic block. Since we
1173: scan from end to beginning, we start with the depth at the end of the
1174: current basic block, and adjust as we pass ends and starts of loops. */
1175: loop_depth = basic_block_loop_depth[bnum];
1176:
1177: dead = (regset) alloca (regset_bytes);
1178: live = (regset) alloca (regset_bytes);
1179:
1180: cc0_live = 0;
1181: last_mem_set = 0;
1182:
1183: /* Include any notes at the end of the block in the scan.
1184: This is in case the block ends with a call to setjmp. */
1185:
1186: while (NEXT_INSN (last) != 0 && GET_CODE (NEXT_INSN (last)) == NOTE)
1187: {
1188: /* Look for loop boundaries, we are going forward here. */
1189: last = NEXT_INSN (last);
1190: if (NOTE_LINE_NUMBER (last) == NOTE_INSN_LOOP_BEG)
1191: loop_depth++;
1192: else if (NOTE_LINE_NUMBER (last) == NOTE_INSN_LOOP_END)
1193: loop_depth--;
1194: }
1195:
1196: if (final)
1197: {
1198: register int i, offset, bit;
1199:
1200: num_scratch = 0;
1201: maxlive = (regset) alloca (regset_bytes);
1202: bcopy (old, maxlive, regset_bytes);
1203: regs_sometimes_live
1204: = (struct foo *) alloca (max_regno * sizeof (struct foo));
1205:
1206: /* Process the regs live at the end of the block.
1207: Enter them in MAXLIVE and REGS_SOMETIMES_LIVE.
1208: Also mark them as not local to any one basic block. */
1209:
1210: for (offset = 0, i = 0; offset < regset_size; offset++)
1211: for (bit = 1; bit; bit <<= 1, i++)
1212: {
1213: if (i == max_regno)
1214: break;
1215: if (old[offset] & bit)
1216: {
1217: reg_basic_block[i] = REG_BLOCK_GLOBAL;
1218: regs_sometimes_live[sometimes_max].offset = offset;
1219: regs_sometimes_live[sometimes_max].bit = i % REGSET_ELT_BITS;
1220: sometimes_max++;
1221: }
1222: }
1223: }
1224:
1225: /* Scan the block an insn at a time from end to beginning. */
1226:
1227: for (insn = last; ; insn = prev)
1228: {
1229: prev = PREV_INSN (insn);
1230:
1231: /* Look for loop boundaries, remembering that we are going backwards. */
1232: if (GET_CODE (insn) == NOTE
1233: && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
1234: loop_depth++;
1235: else if (GET_CODE (insn) == NOTE
1236: && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
1237: loop_depth--;
1238:
1239: /* If we have LOOP_DEPTH == 0, there has been a bookkeeping error.
1240: Abort now rather than setting register status incorrectly. */
1241: if (loop_depth == 0)
1242: abort ();
1243:
1244: /* If this is a call to `setjmp' et al,
1245: warn if any non-volatile datum is live. */
1246:
1247: if (final && GET_CODE (insn) == NOTE
1248: && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
1249: {
1250: int i;
1251: for (i = 0; i < regset_size; i++)
1252: regs_live_at_setjmp[i] |= old[i];
1253: }
1254:
1255: /* Update the life-status of regs for this insn.
1256: First DEAD gets which regs are set in this insn
1257: then LIVE gets which regs are used in this insn.
1258: Then the regs live before the insn
1259: are those live after, with DEAD regs turned off,
1260: and then LIVE regs turned on. */
1261:
1262: if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
1263: {
1264: register int i;
1265: rtx note = find_reg_note (insn, REG_RETVAL, 0);
1266: int insn_is_dead
1267: = (insn_dead_p (PATTERN (insn), old, 0)
1268: /* Don't delete something that refers to volatile storage! */
1269: && ! INSN_VOLATILE (insn));
1270: int libcall_is_dead
1271: = (insn_is_dead && note != 0
1272: && libcall_dead_p (PATTERN (insn), old, note, insn));
1273:
1274: /* If an instruction consists of just dead store(s) on final pass,
1275: "delete" it by turning it into a NOTE of type NOTE_INSN_DELETED.
1276: We could really delete it with delete_insn, but that
1277: can cause trouble for first or last insn in a basic block. */
1278: if (final && insn_is_dead)
1279: {
1280: PUT_CODE (insn, NOTE);
1281: NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
1282: NOTE_SOURCE_FILE (insn) = 0;
1283:
1284: /* If this insn is copying the return value from a library call,
1285: delete the entire library call. */
1286: if (libcall_is_dead)
1287: {
1288: rtx first = XEXP (note, 0);
1289: rtx p = insn;
1290: while (INSN_DELETED_P (first))
1291: first = NEXT_INSN (first);
1292: while (p != first)
1293: {
1294: p = PREV_INSN (p);
1295: PUT_CODE (p, NOTE);
1296: NOTE_LINE_NUMBER (p) = NOTE_INSN_DELETED;
1297: NOTE_SOURCE_FILE (p) = 0;
1298: }
1299: }
1300: goto flushed;
1301: }
1302:
1303: for (i = 0; i < regset_size; i++)
1304: {
1305: dead[i] = 0; /* Faster than bzero here */
1306: live[i] = 0; /* since regset_size is usually small */
1307: }
1308:
1309: /* See if this is an increment or decrement that can be
1310: merged into a following memory address. */
1311: #ifdef AUTO_INC_DEC
1312: {
1313: register rtx x = PATTERN (insn);
1314: /* Does this instruction increment or decrement a register? */
1315: if (final && GET_CODE (x) == SET
1316: && GET_CODE (SET_DEST (x)) == REG
1317: && (GET_CODE (SET_SRC (x)) == PLUS
1318: || GET_CODE (SET_SRC (x)) == MINUS)
1319: && XEXP (SET_SRC (x), 0) == SET_DEST (x)
1320: && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
1321: /* Ok, look for a following memory ref we can combine with.
1322: If one is found, change the memory ref to a PRE_INC
1323: or PRE_DEC, cancel this insn, and return 1.
1324: Return 0 if nothing has been done. */
1325: && try_pre_increment_1 (insn))
1326: goto flushed;
1327: }
1328: #endif /* AUTO_INC_DEC */
1329:
1330: /* If this is not the final pass, and this insn is copying the
1331: value of a library call and it's dead, don't scan the
1332: insns that perform the library call, so that the call's
1333: arguments are not marked live. */
1334: if (libcall_is_dead)
1335: {
1336: /* Mark the dest reg as `significant'. */
1337: mark_set_regs (old, dead, PATTERN (insn), 0, significant);
1338:
1339: insn = XEXP (note, 0);
1340: prev = PREV_INSN (insn);
1341: }
1342: else if (GET_CODE (PATTERN (insn)) == SET
1343: && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
1344: && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
1345: && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
1346: && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
1347: /* We have an insn to pop a constant amount off the stack.
1348: (Such insns use PLUS regardless of the direction of the stack,
1349: and any insn to adjust the stack by a constant is always a pop.)
1350: These insns, if not dead stores, have no effect on life. */
1351: ;
1352: else
1353: {
1354: /* LIVE gets the regs used in INSN;
1355: DEAD gets those set by it. Dead insns don't make anything
1356: live. */
1357:
1358: mark_set_regs (old, dead, PATTERN (insn), final ? insn : 0,
1359: significant);
1360:
1361: /* If an insn doesn't use CC0, it becomes dead since we
1362: assume that every insn clobbers it. So show it dead here;
1363: mark_used_regs will set it live if it is referenced. */
1364: cc0_live = 0;
1365:
1366: if (! insn_is_dead)
1367: mark_used_regs (old, live, PATTERN (insn), final, insn);
1368:
1369: /* Sometimes we may have inserted something before INSN (such as
1370: a move) when we make an auto-inc. So ensure we will scan
1371: those insns. */
1372: #ifdef AUTO_INC_DEC
1373: prev = PREV_INSN (insn);
1374: #endif
1375:
1376: if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
1377: {
1378: register int i;
1379:
1380: /* Each call clobbers all call-clobbered regs that are not
1381: global. Note that the function-value reg is a
1382: call-clobbered reg, and mark_set_regs has already had
1383: a chance to handle it. */
1384:
1385: for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1386: if (call_used_regs[i] && ! global_regs[i])
1387: dead[i / REGSET_ELT_BITS]
1388: |= (1 << (i % REGSET_ELT_BITS));
1389:
1390: /* The stack ptr is used (honorarily) by a CALL insn. */
1391: live[STACK_POINTER_REGNUM / REGSET_ELT_BITS]
1392: |= (1 << (STACK_POINTER_REGNUM % REGSET_ELT_BITS));
1393:
1394: /* Calls may also reference any of the global registers,
1395: so they are made live. */
1396:
1397: for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1398: if (global_regs[i])
1399: live[i / REGSET_ELT_BITS]
1400: |= (1 << (i % REGSET_ELT_BITS));
1401:
1402: /* Calls also clobber memory. */
1403: last_mem_set = 0;
1404: }
1405:
1406: /* Update OLD for the registers used or set. */
1407: for (i = 0; i < regset_size; i++)
1408: {
1409: old[i] &= ~dead[i];
1410: old[i] |= live[i];
1411: }
1412:
1413: if (GET_CODE (insn) == CALL_INSN && final)
1414: {
1415: /* Any regs live at the time of a call instruction
1416: must not go in a register clobbered by calls.
1417: Find all regs now live and record this for them. */
1418:
1419: register struct foo *p = regs_sometimes_live;
1420:
1421: for (i = 0; i < sometimes_max; i++, p++)
1422: if (old[p->offset] & (1 << p->bit))
1423: reg_n_calls_crossed[p->offset * REGSET_ELT_BITS + p->bit]+= 1;
1424: }
1425: }
1426:
1427: /* On final pass, add any additional sometimes-live regs
1428: into MAXLIVE and REGS_SOMETIMES_LIVE.
1429: Also update counts of how many insns each reg is live at. */
1430:
1431: if (final)
1432: {
1433: for (i = 0; i < regset_size; i++)
1434: {
1435: register int diff = live[i] & ~maxlive[i];
1436:
1437: if (diff)
1438: {
1439: register int regno;
1440: maxlive[i] |= diff;
1441: for (regno = 0; diff && regno < REGSET_ELT_BITS; regno++)
1442: if (diff & (1 << regno))
1443: {
1444: regs_sometimes_live[sometimes_max].offset = i;
1445: regs_sometimes_live[sometimes_max].bit = regno;
1446: diff &= ~ (1 << regno);
1447: sometimes_max++;
1448: }
1449: }
1450: }
1451:
1452: {
1453: register struct foo *p = regs_sometimes_live;
1454: for (i = 0; i < sometimes_max; i++, p++)
1455: {
1456: if (old[p->offset] & (1 << p->bit))
1457: reg_live_length[p->offset * REGSET_ELT_BITS + p->bit]++;
1458: }
1459: }
1460: }
1461: }
1462: flushed: ;
1463: if (insn == first)
1464: break;
1465: }
1466:
1467: if (num_scratch > max_scratch)
1468: max_scratch = num_scratch;
1469: }
1470:
1471: /* Return 1 if X (the body of an insn, or part of it) is just dead stores
1472: (SET expressions whose destinations are registers dead after the insn).
1473: NEEDED is the regset that says which regs are alive after the insn.
1474:
1475: Unless CALL_OK is non-zero, an insn is needed if it contains a CALL. */
1476:
1477: static int
1478: insn_dead_p (x, needed, call_ok)
1479: rtx x;
1480: regset needed;
1481: int call_ok;
1482: {
1483: register RTX_CODE code = GET_CODE (x);
1484: /* If setting something that's a reg or part of one,
1485: see if that register's altered value will be live. */
1486:
1487: if (code == SET)
1488: {
1489: register rtx r = SET_DEST (x);
1490: /* A SET that is a subroutine call cannot be dead. */
1491: if (! call_ok && GET_CODE (SET_SRC (x)) == CALL)
1492: return 0;
1493:
1494: #ifdef HAVE_cc0
1495: if (GET_CODE (r) == CC0)
1496: return ! cc0_live;
1497: #endif
1498:
1499: if (GET_CODE (r) == MEM && last_mem_set && ! MEM_VOLATILE_P (r)
1500: && rtx_equal_p (r, last_mem_set))
1501: return 1;
1502:
1503: while (GET_CODE (r) == SUBREG
1504: || GET_CODE (r) == STRICT_LOW_PART
1505: || GET_CODE (r) == ZERO_EXTRACT
1506: || GET_CODE (r) == SIGN_EXTRACT)
1507: r = SUBREG_REG (r);
1508:
1509: if (GET_CODE (r) == REG)
1510: {
1511: register int regno = REGNO (r);
1512: register int offset = regno / REGSET_ELT_BITS;
1513: register int bit = 1 << (regno % REGSET_ELT_BITS);
1514:
1515: if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
1516: /* Make sure insns to set frame pointer aren't deleted. */
1517: || regno == FRAME_POINTER_REGNUM
1518: #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1519: /* Make sure insns to set arg pointer are never deleted
1520: (if the arg pointer isn't fixed, there will be a USE for
1521: it, so we can treat it normally). */
1522: || (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
1523: #endif
1524: || (needed[offset] & bit) != 0)
1525: return 0;
1526:
1527: /* If this is a hard register, verify that subsequent words are
1528: not needed. */
1529: if (regno < FIRST_PSEUDO_REGISTER)
1530: {
1531: int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
1532:
1533: while (--n > 0)
1534: if ((needed[(regno + n) / REGSET_ELT_BITS]
1535: & 1 << ((regno + n) % REGSET_ELT_BITS)) != 0)
1536: return 0;
1537: }
1538:
1539: return 1;
1540: }
1541: }
1542: /* If performing several activities,
1543: insn is dead if each activity is individually dead.
1544: Also, CLOBBERs and USEs can be ignored; a CLOBBER or USE
1545: that's inside a PARALLEL doesn't make the insn worth keeping. */
1546: else if (code == PARALLEL)
1547: {
1548: register int i = XVECLEN (x, 0);
1549: for (i--; i >= 0; i--)
1550: {
1551: rtx elt = XVECEXP (x, 0, i);
1552: if (!insn_dead_p (elt, needed, call_ok)
1553: && GET_CODE (elt) != CLOBBER
1554: && GET_CODE (elt) != USE)
1555: return 0;
1556: }
1557: return 1;
1558: }
1559: /* We do not check CLOBBER or USE here.
1560: An insn consisting of just a CLOBBER or just a USE
1561: should not be deleted. */
1562: return 0;
1563: }
1564:
1565: /* If X is the pattern of the last insn in a libcall, and assuming X is dead,
1566: return 1 if the entire library call is dead.
1567: This is true if X copies a register (hard or pseudo)
1568: and if the hard return reg of the call insn is dead.
1569: (The caller should have tested the destination of X already for death.)
1570:
1571: If this insn doesn't just copy a register, then we don't
1572: have an ordinary libcall. In that case, cse could not have
1573: managed to substitute the source for the dest later on,
1574: so we can assume the libcall is dead.
1575:
1576: NEEDED is the bit vector of pseudoregs live before this insn.
1577: NOTE is the REG_RETVAL note of the insn. INSN is the insn itself. */
1578:
1579: static int
1580: libcall_dead_p (x, needed, note, insn)
1581: rtx x;
1582: regset needed;
1583: rtx note;
1584: rtx insn;
1585: {
1586: register RTX_CODE code = GET_CODE (x);
1587:
1588: if (code == SET)
1589: {
1590: register rtx r = SET_SRC (x);
1591: if (GET_CODE (r) == REG)
1592: {
1593: rtx call = XEXP (note, 0);
1594: register int i;
1595:
1596: /* Find the call insn. */
1597: while (call != insn && GET_CODE (call) != CALL_INSN)
1598: call = NEXT_INSN (call);
1599:
1600: /* If there is none, do nothing special,
1601: since ordinary death handling can understand these insns. */
1602: if (call == insn)
1603: return 0;
1604:
1605: /* See if the hard reg holding the value is dead.
1606: If this is a PARALLEL, find the call within it. */
1607: call = PATTERN (call);
1608: if (GET_CODE (call) == PARALLEL)
1609: {
1610: for (i = XVECLEN (call, 0) - 1; i >= 0; i--)
1611: if (GET_CODE (XVECEXP (call, 0, i)) == SET
1612: && GET_CODE (SET_SRC (XVECEXP (call, 0, i))) == CALL)
1613: break;
1614:
1615: if (i < 0)
1616: abort ();
1617:
1618: call = XVECEXP (call, 0, i);
1619: }
1620:
1621: return insn_dead_p (call, needed, 1);
1622: }
1623: }
1624: return 1;
1625: }
1626:
1627: /* Return 1 if register REGNO was used before it was set.
1628: In other words, if it is live at function entry. */
1629:
1630: int
1631: regno_uninitialized (regno)
1632: int regno;
1633: {
1634: if (n_basic_blocks == 0)
1635: return 0;
1636:
1637: return (basic_block_live_at_start[0][regno / REGSET_ELT_BITS]
1638: & (1 << (regno % REGSET_ELT_BITS)));
1639: }
1640:
1641: /* 1 if register REGNO was alive at a place where `setjmp' was called
1642: and was set more than once or is an argument.
1643: Such regs may be clobbered by `longjmp'. */
1644:
1645: int
1646: regno_clobbered_at_setjmp (regno)
1647: int regno;
1648: {
1649: if (n_basic_blocks == 0)
1650: return 0;
1651:
1652: return ((reg_n_sets[regno] > 1
1653: || (basic_block_live_at_start[0][regno / REGSET_ELT_BITS]
1654: & (1 << (regno % REGSET_ELT_BITS))))
1655: && (regs_live_at_setjmp[regno / REGSET_ELT_BITS]
1656: & (1 << (regno % REGSET_ELT_BITS))));
1657: }
1658:
1659: /* Process the registers that are set within X.
1660: Their bits are set to 1 in the regset DEAD,
1661: because they are dead prior to this insn.
1662:
1663: If INSN is nonzero, it is the insn being processed
1664: and the fact that it is nonzero implies this is the FINAL pass
1665: in propagate_block. In this case, various info about register
1666: usage is stored, LOG_LINKS fields of insns are set up. */
1667:
1668: static void mark_set_1 ();
1669:
1670: static void
1671: mark_set_regs (needed, dead, x, insn, significant)
1672: regset needed;
1673: regset dead;
1674: rtx x;
1675: rtx insn;
1676: regset significant;
1677: {
1678: register RTX_CODE code = GET_CODE (x);
1679:
1680: if (code == SET || code == CLOBBER)
1681: mark_set_1 (needed, dead, x, insn, significant);
1682: else if (code == PARALLEL)
1683: {
1684: register int i;
1685: for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
1686: {
1687: code = GET_CODE (XVECEXP (x, 0, i));
1688: if (code == SET || code == CLOBBER)
1689: mark_set_1 (needed, dead, XVECEXP (x, 0, i), insn, significant);
1690: }
1691: }
1692: }
1693:
1694: /* Process a single SET rtx, X. */
1695:
1696: static void
1697: mark_set_1 (needed, dead, x, insn, significant)
1698: regset needed;
1699: regset dead;
1700: rtx x;
1701: rtx insn;
1702: regset significant;
1703: {
1704: register int regno;
1705: register rtx reg = SET_DEST (x);
1706:
1707: /* Modifying just one hardware register of a multi-reg value
1708: or just a byte field of a register
1709: does not mean the value from before this insn is now dead.
1710: But it does mean liveness of that register at the end of the block
1711: is significant.
1712:
1713: Within mark_set_1, however, we treat it as if the register is
1714: indeed modified. mark_used_regs will, however, also treat this
1715: register as being used. Thus, we treat these insns as setting a
1716: new value for the register as a function of its old value. This
1717: cases LOG_LINKS to be made appropriately and this will help combine. */
1718:
1719: while (GET_CODE (reg) == SUBREG || GET_CODE (reg) == ZERO_EXTRACT
1720: || GET_CODE (reg) == SIGN_EXTRACT
1721: || GET_CODE (reg) == STRICT_LOW_PART)
1722: reg = XEXP (reg, 0);
1723:
1724: /* If we are writing into memory or into a register mentioned in the
1725: address of the last thing stored into memory, show we don't know
1726: what the last store was. If we are writing memory, save the address
1727: unless it is volatile. */
1728: if (GET_CODE (reg) == MEM
1729: || (GET_CODE (reg) == REG
1730: && last_mem_set != 0 && reg_overlap_mentioned_p (reg, last_mem_set)))
1731: last_mem_set = 0;
1732:
1733: if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
1734: /* There are no REG_INC notes for SP, so we can't assume we'll see
1735: everything that invalidates it. To be safe, don't eliminate any
1736: stores though SP; none of them should be redundant anyway. */
1737: && ! reg_mentioned_p (stack_pointer_rtx, reg))
1738: last_mem_set = reg;
1739:
1740: if (GET_CODE (reg) == REG
1741: && (regno = REGNO (reg), regno != FRAME_POINTER_REGNUM)
1742: #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1743: && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
1744: #endif
1745: && ! (regno < FIRST_PSEUDO_REGISTER && global_regs[regno]))
1746: /* && regno != STACK_POINTER_REGNUM) -- let's try without this. */
1747: {
1748: register int offset = regno / REGSET_ELT_BITS;
1749: register int bit = 1 << (regno % REGSET_ELT_BITS);
1750: int all_needed = (needed[offset] & bit) != 0;
1751: int some_needed = (needed[offset] & bit) != 0;
1752:
1753: /* Mark it as a significant register for this basic block. */
1754: if (significant)
1755: significant[offset] |= bit;
1756:
1757: /* Mark it as as dead before this insn. */
1758: dead[offset] |= bit;
1759:
1760: /* A hard reg in a wide mode may really be multiple registers.
1761: If so, mark all of them just like the first. */
1762: if (regno < FIRST_PSEUDO_REGISTER)
1763: {
1764: int n;
1765:
1766: /* Nothing below is needed for the stack pointer; get out asap.
1767: Eg, log links aren't needed, since combine won't use them. */
1768: if (regno == STACK_POINTER_REGNUM)
1769: return;
1770:
1771: n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
1772: while (--n > 0)
1773: {
1774: if (significant)
1775: significant[(regno + n) / REGSET_ELT_BITS]
1776: |= 1 << ((regno + n) % REGSET_ELT_BITS);
1777: dead[(regno + n) / REGSET_ELT_BITS]
1778: |= 1 << ((regno + n) % REGSET_ELT_BITS);
1779: some_needed |= (needed[(regno + n) / REGSET_ELT_BITS]
1780: & 1 << ((regno + n) % REGSET_ELT_BITS));
1781: all_needed &= (needed[(regno + n) / REGSET_ELT_BITS]
1782: & 1 << ((regno + n) % REGSET_ELT_BITS));
1783: }
1784: }
1785: /* Additional data to record if this is the final pass. */
1786: if (insn)
1787: {
1788: register rtx y = reg_next_use[regno];
1789: register int blocknum = BLOCK_NUM (insn);
1790:
1791: /* If this is a hard reg, record this function uses the reg. */
1792:
1793: if (regno < FIRST_PSEUDO_REGISTER)
1794: {
1795: register int i;
1796: int endregno = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg));
1797:
1798: for (i = regno; i < endregno; i++)
1799: {
1800: regs_ever_live[i] = 1;
1801: reg_n_sets[i]++;
1802: }
1803: }
1804: else
1805: {
1806: /* Keep track of which basic blocks each reg appears in. */
1807:
1808: if (reg_basic_block[regno] == REG_BLOCK_UNKNOWN)
1809: reg_basic_block[regno] = blocknum;
1810: else if (reg_basic_block[regno] != blocknum)
1811: reg_basic_block[regno] = REG_BLOCK_GLOBAL;
1812:
1813: /* Count (weighted) references, stores, etc. This counts a
1814: register twice if it is modified, but that is correct. */
1815: reg_n_sets[regno]++;
1816:
1817: reg_n_refs[regno] += loop_depth;
1818:
1819: /* The insns where a reg is live are normally counted
1820: elsewhere, but we want the count to include the insn
1821: where the reg is set, and the normal counting mechanism
1822: would not count it. */
1823: reg_live_length[regno]++;
1824: }
1825:
1826: /* The next use is no longer "next", since a store intervenes. */
1827: reg_next_use[regno] = 0;
1828:
1829: if (all_needed)
1830: {
1831: /* Make a logical link from the next following insn
1832: that uses this register, back to this insn.
1833: The following insns have already been processed.
1834:
1835: We don't build a LOG_LINK for hard registers containing
1836: in ASM_OPERANDs. If these registers get replaced,
1837: we might wind up changing the semantics of the insn,
1838: even if reload can make what appear to be valid assignments
1839: later. */
1840: if (y && (BLOCK_NUM (y) == blocknum)
1841: && (regno >= FIRST_PSEUDO_REGISTER
1842: || asm_noperands (PATTERN (y)) < 0))
1843: LOG_LINKS (y)
1844: = gen_rtx (INSN_LIST, VOIDmode, insn, LOG_LINKS (y));
1845: }
1846: else if (! some_needed)
1847: {
1848: /* Note that dead stores have already been deleted when possible
1849: If we get here, we have found a dead store that cannot
1850: be eliminated (because the same insn does something useful).
1851: Indicate this by marking the reg being set as dying here. */
1852: REG_NOTES (insn)
1853: = gen_rtx (EXPR_LIST, REG_UNUSED, reg, REG_NOTES (insn));
1854: reg_n_deaths[REGNO (reg)]++;
1855: }
1856: else
1857: {
1858: /* This is a case where we have a multi-word hard register
1859: and some, but not all, of the words of the register are
1860: needed in subsequent insns. Write REG_UNUSED notes
1861: for those parts that were not needed. This case should
1862: be rare. */
1863:
1864: int i;
1865:
1866: for (i = HARD_REGNO_NREGS (regno, GET_MODE (reg)) - 1;
1867: i >= 0; i--)
1868: if ((needed[(regno + i) / REGSET_ELT_BITS]
1869: & 1 << ((regno + i) % REGSET_ELT_BITS)) == 0)
1870: REG_NOTES (insn)
1871: = gen_rtx (EXPR_LIST, REG_UNUSED,
1872: gen_rtx (REG, word_mode, regno + i),
1873: REG_NOTES (insn));
1874: }
1875: }
1876: }
1877:
1878: /* If this is the last pass and this is a SCRATCH, show it will be dying
1879: here and count it. */
1880: else if (GET_CODE (reg) == SCRATCH && insn != 0)
1881: {
1882: REG_NOTES (insn)
1883: = gen_rtx (EXPR_LIST, REG_UNUSED, reg, REG_NOTES (insn));
1884: num_scratch++;
1885: }
1886: }
1887:
1888: #ifdef AUTO_INC_DEC
1889:
1890: /* X is a MEM found in INSN. See if we can convert it into an auto-increment
1891: reference. */
1892:
1893: static void
1894: find_auto_inc (needed, x, insn)
1895: regset needed;
1896: rtx x;
1897: rtx insn;
1898: {
1899: rtx addr = XEXP (x, 0);
1900: int offset = 0;
1901:
1902: /* Here we detect use of an index register which might be good for
1903: postincrement, postdecrement, preincrement, or predecrement. */
1904:
1905: if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
1906: offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
1907:
1908: if (GET_CODE (addr) == REG)
1909: {
1910: register rtx y;
1911: register int size = GET_MODE_SIZE (GET_MODE (x));
1912: rtx use;
1913: rtx incr;
1914: int regno = REGNO (addr);
1915:
1916: /* Is the next use an increment that might make auto-increment? */
1917: incr = reg_next_use[regno];
1918: if (incr && GET_CODE (PATTERN (incr)) == SET
1919: && BLOCK_NUM (incr) == BLOCK_NUM (insn)
1920: /* Can't add side effects to jumps; if reg is spilled and
1921: reloaded, there's no way to store back the altered value. */
1922: && GET_CODE (insn) != JUMP_INSN
1923: && (y = SET_SRC (PATTERN (incr)), GET_CODE (y) == PLUS)
1924: && XEXP (y, 0) == addr
1925: && GET_CODE (XEXP (y, 1)) == CONST_INT
1926: && (0
1927: #ifdef HAVE_POST_INCREMENT
1928: || (INTVAL (XEXP (y, 1)) == size && offset == 0)
1929: #endif
1930: #ifdef HAVE_POST_DECREMENT
1931: || (INTVAL (XEXP (y, 1)) == - size && offset == 0)
1932: #endif
1933: #ifdef HAVE_PRE_INCREMENT
1934: || (INTVAL (XEXP (y, 1)) == size && offset == size)
1935: #endif
1936: #ifdef HAVE_PRE_DECREMENT
1937: || (INTVAL (XEXP (y, 1)) == - size && offset == - size)
1938: #endif
1939: )
1940: /* Make sure this reg appears only once in this insn. */
1941: && (use = find_use_as_address (PATTERN (insn), addr, offset),
1942: use != 0 && use != (rtx) 1))
1943: {
1944: int win = 0;
1945: rtx q = SET_DEST (PATTERN (incr));
1946:
1947: if (dead_or_set_p (incr, addr))
1948: win = 1;
1949: else if (GET_CODE (q) == REG && ! reg_used_between_p (q, insn, incr))
1950: {
1951: /* We have *p followed by q = p+size.
1952: Both p and q must be live afterward,
1953: and q must be dead before.
1954: Change it to q = p, ...*q..., q = q+size.
1955: Then fall into the usual case. */
1956: rtx insns, temp;
1957:
1958: start_sequence ();
1959: emit_move_insn (q, addr);
1960: insns = get_insns ();
1961: end_sequence ();
1962:
1963: /* If anything in INSNS have UID's that don't fit within the
1964: extra space we allocate earlier, we can't make this auto-inc.
1965: This should never happen. */
1966: for (temp = insns; temp; temp = NEXT_INSN (temp))
1967: {
1968: if (INSN_UID (temp) > max_uid_for_flow)
1969: return;
1970: BLOCK_NUM (temp) = BLOCK_NUM (insn);
1971: }
1972:
1973: emit_insns_before (insns, insn);
1974:
1975: if (basic_block_head[BLOCK_NUM (insn)] == insn)
1976: basic_block_head[BLOCK_NUM (insn)] = insns;
1977:
1978: XEXP (x, 0) = q;
1979: XEXP (y, 0) = q;
1980:
1981: /* INCR will become a NOTE and INSN won't contain a
1982: use of ADDR. If a use of ADDR was just placed in
1983: the insn before INSN, make that the next use.
1984: Otherwise, invalidate it. */
1985: if (GET_CODE (PREV_INSN (insn)) == INSN
1986: && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
1987: && SET_SRC (PATTERN (PREV_INSN (insn))) == addr)
1988: reg_next_use[regno] = PREV_INSN (insn);
1989: else
1990: reg_next_use[regno] = 0;
1991:
1992: addr = q;
1993: regno = REGNO (q);
1994: win = 1;
1995:
1996: /* REGNO is now used in INCR which is below INSN, but
1997: it previously wasn't live here. If we don't mark
1998: it as needed, we'll put a REG_DEAD note for it
1999: on this insn, which is incorrect. */
2000: needed[regno / REGSET_ELT_BITS]
2001: |= 1 << (regno % REGSET_ELT_BITS);
2002:
2003: /* If there are any calls between INSN and INCR, show
2004: that REGNO now crosses them. */
2005: for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
2006: if (GET_CODE (temp) == CALL_INSN)
2007: reg_n_calls_crossed[regno]++;
2008: }
2009:
2010: if (win)
2011: {
2012: /* We have found a suitable auto-increment: do POST_INC around
2013: the register here, and patch out the increment instruction
2014: that follows. */
2015: XEXP (x, 0) = gen_rtx ((INTVAL (XEXP (y, 1)) == size
2016: ? (offset ? PRE_INC : POST_INC)
2017: : (offset ? PRE_DEC : POST_DEC)),
2018: Pmode, addr);
2019:
2020: /* Record that this insn has an implicit side effect. */
2021: REG_NOTES (insn)
2022: = gen_rtx (EXPR_LIST, REG_INC, addr, REG_NOTES (insn));
2023:
2024: /* Modify the old increment-insn to simply copy
2025: the already-incremented value of our register. */
2026: SET_SRC (PATTERN (incr)) = addr;
2027: /* Indicate insn must be re-recognized. */
2028: INSN_CODE (incr) = -1;
2029:
2030: /* If that makes it a no-op (copying the register into itself)
2031: then delete it so it won't appear to be a "use" and a "set"
2032: of this register. */
2033: if (SET_DEST (PATTERN (incr)) == addr)
2034: {
2035: PUT_CODE (incr, NOTE);
2036: NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
2037: NOTE_SOURCE_FILE (incr) = 0;
2038: }
2039:
2040: if (regno >= FIRST_PSEUDO_REGISTER)
2041: {
2042: /* Count an extra reference to the reg. When a reg is
2043: incremented, spilling it is worse, so we want to make
2044: that less likely. */
2045: reg_n_refs[regno] += loop_depth;
2046: /* Count the increment as a setting of the register,
2047: even though it isn't a SET in rtl. */
2048: reg_n_sets[regno]++;
2049: }
2050: }
2051: }
2052: }
2053: }
2054: #endif /* AUTO_INC_DEC */
2055:
2056: /* Scan expression X and store a 1-bit in LIVE for each reg it uses.
2057: This is done assuming the registers needed from X
2058: are those that have 1-bits in NEEDED.
2059:
2060: On the final pass, FINAL is 1. This means try for autoincrement
2061: and count the uses and deaths of each pseudo-reg.
2062:
2063: INSN is the containing instruction. If INSN is dead, this function is not
2064: called. */
2065:
2066: static void
2067: mark_used_regs (needed, live, x, final, insn)
2068: regset needed;
2069: regset live;
2070: rtx x;
2071: rtx insn;
2072: int final;
2073: {
2074: register RTX_CODE code;
2075: register int regno;
2076: int i;
2077:
2078: retry:
2079: code = GET_CODE (x);
2080: switch (code)
2081: {
2082: case LABEL_REF:
2083: case SYMBOL_REF:
2084: case CONST_INT:
2085: case CONST:
2086: case CONST_DOUBLE:
2087: case PC:
2088: case CLOBBER:
2089: case ADDR_VEC:
2090: case ADDR_DIFF_VEC:
2091: case ASM_INPUT:
2092: return;
2093:
2094: #ifdef HAVE_cc0
2095: case CC0:
2096: cc0_live = 1;
2097: return;
2098: #endif
2099:
2100: case MEM:
2101: /* Invalidate the data for the last MEM stored. We could do this only
2102: if the addresses conflict, but this doesn't seem worthwhile. */
2103: last_mem_set = 0;
2104:
2105: #ifdef AUTO_INC_DEC
2106: if (final)
2107: find_auto_inc (needed, x, insn);
2108: #endif
2109: break;
2110:
2111: case REG:
2112: /* See a register other than being set
2113: => mark it as needed. */
2114:
2115: regno = REGNO (x);
2116: {
2117: register int offset = regno / REGSET_ELT_BITS;
2118: register int bit = 1 << (regno % REGSET_ELT_BITS);
2119: int all_needed = (needed[offset] & bit) != 0;
2120: int some_needed = (needed[offset] & bit) != 0;
2121:
2122: live[offset] |= bit;
2123: /* A hard reg in a wide mode may really be multiple registers.
2124: If so, mark all of them just like the first. */
2125: if (regno < FIRST_PSEUDO_REGISTER)
2126: {
2127: int n;
2128:
2129: /* For stack ptr or fixed arg pointer,
2130: nothing below can be necessary, so waste no more time. */
2131: if (regno == STACK_POINTER_REGNUM
2132: #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2133: || (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
2134: #endif
2135: || regno == FRAME_POINTER_REGNUM)
2136: {
2137: /* If this is a register we are going to try to eliminate,
2138: don't mark it live here. If we are successful in
2139: eliminating it, it need not be live unless it is used for
2140: pseudos, in which case it will have been set live when
2141: it was allocated to the pseudos. If the register will not
2142: be eliminated, reload will set it live at that point. */
2143:
2144: if (! TEST_HARD_REG_BIT (elim_reg_set, regno))
2145: regs_ever_live[regno] = 1;
2146: return;
2147: }
2148: /* No death notes for global register variables;
2149: their values are live after this function exits. */
2150: if (global_regs[regno])
2151: return;
2152:
2153: n = HARD_REGNO_NREGS (regno, GET_MODE (x));
2154: while (--n > 0)
2155: {
2156: live[(regno + n) / REGSET_ELT_BITS]
2157: |= 1 << ((regno + n) % REGSET_ELT_BITS);
2158: some_needed |= (needed[(regno + n) / REGSET_ELT_BITS]
2159: & 1 << ((regno + n) % REGSET_ELT_BITS));
2160: all_needed &= (needed[(regno + n) / REGSET_ELT_BITS]
2161: & 1 << ((regno + n) % REGSET_ELT_BITS));
2162: }
2163: }
2164: if (final)
2165: {
2166: /* Record where each reg is used, so when the reg
2167: is set we know the next insn that uses it. */
2168:
2169: reg_next_use[regno] = insn;
2170:
2171: if (regno < FIRST_PSEUDO_REGISTER)
2172: {
2173: /* If a hard reg is being used,
2174: record that this function does use it. */
2175:
2176: i = HARD_REGNO_NREGS (regno, GET_MODE (x));
2177: if (i == 0)
2178: i = 1;
2179: do
2180: regs_ever_live[regno + --i] = 1;
2181: while (i > 0);
2182: }
2183: else
2184: {
2185: /* Keep track of which basic block each reg appears in. */
2186:
2187: register int blocknum = BLOCK_NUM (insn);
2188:
2189: if (reg_basic_block[regno] == REG_BLOCK_UNKNOWN)
2190: reg_basic_block[regno] = blocknum;
2191: else if (reg_basic_block[regno] != blocknum)
2192: reg_basic_block[regno] = REG_BLOCK_GLOBAL;
2193:
2194: /* Count (weighted) number of uses of each reg. */
2195:
2196: reg_n_refs[regno] += loop_depth;
2197: }
2198:
2199: /* Record and count the insns in which a reg dies.
2200: If it is used in this insn and was dead below the insn
2201: then it dies in this insn. If it was set in this insn,
2202: we do not make a REG_DEAD note; likewise if we already
2203: made such a note. */
2204:
2205: if (! all_needed
2206: && ! dead_or_set_p (insn, x)
2207: #if 0
2208: && (regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno])
2209: #endif
2210: )
2211: {
2212: /* If none of the words in X is needed, make a REG_DEAD
2213: note. Otherwise, we must make partial REG_DEAD notes. */
2214: if (! some_needed)
2215: {
2216: REG_NOTES (insn)
2217: = gen_rtx (EXPR_LIST, REG_DEAD, x, REG_NOTES (insn));
2218: reg_n_deaths[regno]++;
2219: }
2220: else
2221: {
2222: int i;
2223:
2224: /* Don't make a REG_DEAD note for a part of a register
2225: that is set in the insn. */
2226:
2227: for (i = HARD_REGNO_NREGS (regno, GET_MODE (x)) - 1;
2228: i >= 0; i--)
2229: if ((needed[(regno + i) / REGSET_ELT_BITS]
2230: & 1 << ((regno + i) % REGSET_ELT_BITS)) == 0
2231: && ! dead_or_set_regno_p (insn, regno + i))
2232: REG_NOTES (insn)
2233: = gen_rtx (EXPR_LIST, REG_DEAD,
2234: gen_rtx (REG, word_mode, regno + i),
2235: REG_NOTES (insn));
2236: }
2237: }
2238: }
2239: }
2240: return;
2241:
2242: case SET:
2243: {
2244: register rtx testreg = SET_DEST (x);
2245: int mark_dest = 0;
2246:
2247: /* If storing into MEM, don't show it as being used. But do
2248: show the address as being used. */
2249: if (GET_CODE (testreg) == MEM)
2250: {
2251: #ifdef AUTO_INC_DEC
2252: if (final)
2253: find_auto_inc (needed, testreg, insn);
2254: #endif
2255: mark_used_regs (needed, live, XEXP (testreg, 0), final, insn);
2256: mark_used_regs (needed, live, SET_SRC (x), final, insn);
2257: return;
2258: }
2259:
2260: /* Storing in STRICT_LOW_PART is like storing in a reg
2261: in that this SET might be dead, so ignore it in TESTREG.
2262: but in some other ways it is like using the reg.
2263:
2264: Storing in a SUBREG or a bit field is like storing the entire
2265: register in that if the register's value is not used
2266: then this SET is not needed. */
2267: while (GET_CODE (testreg) == STRICT_LOW_PART
2268: || GET_CODE (testreg) == ZERO_EXTRACT
2269: || GET_CODE (testreg) == SIGN_EXTRACT
2270: || GET_CODE (testreg) == SUBREG)
2271: {
2272: /* Modifying a single register in an alternate mode
2273: does not use any of the old value. But these other
2274: ways of storing in a register do use the old value. */
2275: if (GET_CODE (testreg) == SUBREG
2276: && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
2277: ;
2278: else
2279: mark_dest = 1;
2280:
2281: testreg = XEXP (testreg, 0);
2282: }
2283:
2284: /* If this is a store into a register,
2285: recursively scan the value being stored. */
2286:
2287: if (GET_CODE (testreg) == REG
2288: && (regno = REGNO (testreg), regno != FRAME_POINTER_REGNUM)
2289: #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2290: && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
2291: #endif
2292: && ! (regno < FIRST_PSEUDO_REGISTER && global_regs[regno]))
2293: {
2294: mark_used_regs (needed, live, SET_SRC (x), final, insn);
2295: if (mark_dest)
2296: mark_used_regs (needed, live, SET_DEST (x), final, insn);
2297: return;
2298: }
2299: }
2300: break;
2301:
2302: case RETURN:
2303: /* If exiting needs the right stack value, consider this insn as
2304: using the stack pointer. In any event, consider it as using
2305: all global registers. */
2306:
2307: #ifdef EXIT_IGNORE_STACK
2308: if (! EXIT_IGNORE_STACK
2309: || (! FRAME_POINTER_REQUIRED && flag_omit_frame_pointer))
2310: #endif
2311: live[STACK_POINTER_REGNUM / REGSET_ELT_BITS]
2312: |= 1 << (STACK_POINTER_REGNUM % REGSET_ELT_BITS);
2313:
2314: for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
2315: if (global_regs[i])
2316: live[i / REGSET_ELT_BITS] |= 1 << (i % REGSET_ELT_BITS);
2317: break;
2318: }
2319:
2320: /* Recursively scan the operands of this expression. */
2321:
2322: {
2323: register char *fmt = GET_RTX_FORMAT (code);
2324: register int i;
2325:
2326: for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2327: {
2328: if (fmt[i] == 'e')
2329: {
2330: /* Tail recursive case: save a function call level. */
2331: if (i == 0)
2332: {
2333: x = XEXP (x, 0);
2334: goto retry;
2335: }
2336: mark_used_regs (needed, live, XEXP (x, i), final, insn);
2337: }
2338: else if (fmt[i] == 'E')
2339: {
2340: register int j;
2341: for (j = 0; j < XVECLEN (x, i); j++)
2342: mark_used_regs (needed, live, XVECEXP (x, i, j), final, insn);
2343: }
2344: }
2345: }
2346: }
2347:
2348: #ifdef AUTO_INC_DEC
2349:
2350: static int
2351: try_pre_increment_1 (insn)
2352: rtx insn;
2353: {
2354: /* Find the next use of this reg. If in same basic block,
2355: make it do pre-increment or pre-decrement if appropriate. */
2356: rtx x = PATTERN (insn);
2357: int amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
2358: * INTVAL (XEXP (SET_SRC (x), 1)));
2359: int regno = REGNO (SET_DEST (x));
2360: rtx y = reg_next_use[regno];
2361: if (y != 0
2362: && BLOCK_NUM (y) == BLOCK_NUM (insn)
2363: && try_pre_increment (y, SET_DEST (PATTERN (insn)),
2364: amount))
2365: {
2366: /* We have found a suitable auto-increment
2367: and already changed insn Y to do it.
2368: So flush this increment-instruction. */
2369: PUT_CODE (insn, NOTE);
2370: NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
2371: NOTE_SOURCE_FILE (insn) = 0;
2372: /* Count a reference to this reg for the increment
2373: insn we are deleting. When a reg is incremented.
2374: spilling it is worse, so we want to make that
2375: less likely. */
2376: if (regno >= FIRST_PSEUDO_REGISTER)
2377: {
2378: reg_n_refs[regno] += loop_depth;
2379: reg_n_sets[regno]++;
2380: }
2381: return 1;
2382: }
2383: return 0;
2384: }
2385:
2386: /* Try to change INSN so that it does pre-increment or pre-decrement
2387: addressing on register REG in order to add AMOUNT to REG.
2388: AMOUNT is negative for pre-decrement.
2389: Returns 1 if the change could be made.
2390: This checks all about the validity of the result of modifying INSN. */
2391:
2392: static int
2393: try_pre_increment (insn, reg, amount)
2394: rtx insn, reg;
2395: int amount;
2396: {
2397: register rtx use;
2398:
2399: /* Nonzero if we can try to make a pre-increment or pre-decrement.
2400: For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
2401: int pre_ok = 0;
2402: /* Nonzero if we can try to make a post-increment or post-decrement.
2403: For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
2404: It is possible for both PRE_OK and POST_OK to be nonzero if the machine
2405: supports both pre-inc and post-inc, or both pre-dec and post-dec. */
2406: int post_ok = 0;
2407:
2408: /* Nonzero if the opportunity actually requires post-inc or post-dec. */
2409: int do_post = 0;
2410:
2411: /* From the sign of increment, see which possibilities are conceivable
2412: on this target machine. */
2413: #ifdef HAVE_PRE_INCREMENT
2414: if (amount > 0)
2415: pre_ok = 1;
2416: #endif
2417: #ifdef HAVE_POST_INCREMENT
2418: if (amount > 0)
2419: post_ok = 1;
2420: #endif
2421:
2422: #ifdef HAVE_PRE_DECREMENT
2423: if (amount < 0)
2424: pre_ok = 1;
2425: #endif
2426: #ifdef HAVE_POST_DECREMENT
2427: if (amount < 0)
2428: post_ok = 1;
2429: #endif
2430:
2431: if (! (pre_ok || post_ok))
2432: return 0;
2433:
2434: /* It is not safe to add a side effect to a jump insn
2435: because if the incremented register is spilled and must be reloaded
2436: there would be no way to store the incremented value back in memory. */
2437:
2438: if (GET_CODE (insn) == JUMP_INSN)
2439: return 0;
2440:
2441: use = 0;
2442: if (pre_ok)
2443: use = find_use_as_address (PATTERN (insn), reg, 0);
2444: if (post_ok && (use == 0 || use == (rtx) 1))
2445: {
2446: use = find_use_as_address (PATTERN (insn), reg, -amount);
2447: do_post = 1;
2448: }
2449:
2450: if (use == 0 || use == (rtx) 1)
2451: return 0;
2452:
2453: if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
2454: return 0;
2455:
2456: XEXP (use, 0) = gen_rtx (amount > 0
2457: ? (do_post ? POST_INC : PRE_INC)
2458: : (do_post ? POST_DEC : PRE_DEC),
2459: Pmode, reg);
2460:
2461: /* Record that this insn now has an implicit side effect on X. */
2462: REG_NOTES (insn) = gen_rtx (EXPR_LIST, REG_INC, reg, REG_NOTES (insn));
2463: return 1;
2464: }
2465:
2466: #endif /* AUTO_INC_DEC */
2467:
2468: /* Find the place in the rtx X where REG is used as a memory address.
2469: Return the MEM rtx that so uses it.
2470: If PLUSCONST is nonzero, search instead for a memory address equivalent to
2471: (plus REG (const_int PLUSCONST)).
2472:
2473: If such an address does not appear, return 0.
2474: If REG appears more than once, or is used other than in such an address,
2475: return (rtx)1. */
2476:
2477: static rtx
2478: find_use_as_address (x, reg, plusconst)
2479: register rtx x;
2480: rtx reg;
2481: int plusconst;
2482: {
2483: enum rtx_code code = GET_CODE (x);
2484: char *fmt = GET_RTX_FORMAT (code);
2485: register int i;
2486: register rtx value = 0;
2487: register rtx tem;
2488:
2489: if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
2490: return x;
2491:
2492: if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
2493: && XEXP (XEXP (x, 0), 0) == reg
2494: && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
2495: && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
2496: return x;
2497:
2498: if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
2499: {
2500: /* If REG occurs inside a MEM used in a bit-field reference,
2501: that is unacceptable. */
2502: if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
2503: return (rtx) 1;
2504: }
2505:
2506: if (x == reg)
2507: return (rtx) 1;
2508:
2509: for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2510: {
2511: if (fmt[i] == 'e')
2512: {
2513: tem = find_use_as_address (XEXP (x, i), reg, plusconst);
2514: if (value == 0)
2515: value = tem;
2516: else if (tem != 0)
2517: return (rtx) 1;
2518: }
2519: if (fmt[i] == 'E')
2520: {
2521: register int j;
2522: for (j = XVECLEN (x, i) - 1; j >= 0; j--)
2523: {
2524: tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
2525: if (value == 0)
2526: value = tem;
2527: else if (tem != 0)
2528: return (rtx) 1;
2529: }
2530: }
2531: }
2532:
2533: return value;
2534: }
2535:
2536: /* Write information about registers and basic blocks into FILE.
2537: This is part of making a debugging dump. */
2538:
2539: void
2540: dump_flow_info (file)
2541: FILE *file;
2542: {
2543: register int i;
2544: static char *reg_class_names[] = REG_CLASS_NAMES;
2545:
2546: fprintf (file, "%d registers.\n", max_regno);
2547:
2548: for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
2549: if (reg_n_refs[i])
2550: {
2551: enum reg_class class;
2552: fprintf (file, "\nRegister %d used %d times across %d insns",
2553: i, reg_n_refs[i], reg_live_length[i]);
2554: if (reg_basic_block[i] >= 0)
2555: fprintf (file, " in block %d", reg_basic_block[i]);
2556: if (reg_n_deaths[i] != 1)
2557: fprintf (file, "; dies in %d places", reg_n_deaths[i]);
2558: if (reg_n_calls_crossed[i] == 1)
2559: fprintf (file, "; crosses 1 call");
2560: else if (reg_n_calls_crossed[i])
2561: fprintf (file, "; crosses %d calls", reg_n_calls_crossed[i]);
2562: if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
2563: fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
2564: class = reg_preferred_class (i);
2565: if (class != GENERAL_REGS)
2566: {
2567: if (reg_preferred_or_nothing (i))
2568: fprintf (file, "; %s or none", reg_class_names[(int) class]);
2569: else
2570: fprintf (file, "; pref %s", reg_class_names[(int) class]);
2571: }
2572: if (REGNO_POINTER_FLAG (i))
2573: fprintf (file, "; pointer");
2574: fprintf (file, ".\n");
2575: }
2576: fprintf (file, "\n%d basic blocks.\n", n_basic_blocks);
2577: for (i = 0; i < n_basic_blocks; i++)
2578: {
2579: register rtx head, jump;
2580: register int regno;
2581: fprintf (file, "\nBasic block %d: first insn %d, last %d.\n",
2582: i,
2583: INSN_UID (basic_block_head[i]),
2584: INSN_UID (basic_block_end[i]));
2585: /* The control flow graph's storage is freed
2586: now when flow_analysis returns.
2587: Don't try to print it if it is gone. */
2588: if (basic_block_drops_in)
2589: {
2590: fprintf (file, "Reached from blocks: ");
2591: head = basic_block_head[i];
2592: if (GET_CODE (head) == CODE_LABEL)
2593: for (jump = LABEL_REFS (head);
2594: jump != head;
2595: jump = LABEL_NEXTREF (jump))
2596: {
2597: register int from_block = BLOCK_NUM (CONTAINING_INSN (jump));
2598: fprintf (file, " %d", from_block);
2599: }
2600: if (basic_block_drops_in[i])
2601: fprintf (file, " previous");
2602: }
2603: fprintf (file, "\nRegisters live at start:");
2604: for (regno = 0; regno < max_regno; regno++)
2605: {
2606: register int offset = regno / REGSET_ELT_BITS;
2607: register int bit = 1 << (regno % REGSET_ELT_BITS);
2608: if (basic_block_live_at_start[i][offset] & bit)
2609: fprintf (file, " %d", regno);
2610: }
2611: fprintf (file, "\n");
2612: }
2613: fprintf (file, "\n");
2614: }
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