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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:
1.1.1.3 ! root 469: /* Don't separate a CALL_INSN from following CLOBBER insns. This is
1.1 root 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
1.1.1.3 ! root 522: && (GET_CODE (SET_SRC (PATTERN (insn))) == REG
! 523: || GET_CODE (SET_SRC (PATTERN (insn))) == MEM))
1.1 root 524: {
525: rtx x;
526: for (x = label_value_list; x; x = XEXP (x, 1))
527: mark_label_ref (gen_rtx (LABEL_REF, VOIDmode, XEXP (x, 0)),
528: insn, 0);
529: for (x = forced_labels; x; x = XEXP (x, 1))
530: mark_label_ref (gen_rtx (LABEL_REF, VOIDmode, XEXP (x, 0)),
531: insn, 0);
532: }
533:
534: /* Find all call insns and mark them as possibly jumping
535: to all the nonlocal goto handler labels. */
536:
537: for (insn = f; insn; insn = NEXT_INSN (insn))
538: if (GET_CODE (insn) == CALL_INSN)
539: {
540: rtx x;
541: for (x = nonlocal_label_list; x; x = XEXP (x, 1))
542: mark_label_ref (gen_rtx (LABEL_REF, VOIDmode, XEXP (x, 0)),
543: insn, 0);
544: /* ??? This could be made smarter:
545: in some cases it's possible to tell that certain
546: calls will not do a nonlocal goto.
547:
548: For example, if the nested functions that do the
549: nonlocal gotos do not have their addresses taken, then
550: only calls to those functions or to other nested
551: functions that use them could possibly do nonlocal
552: gotos. */
553: }
554:
555: /* Pass over all blocks, marking each block that is reachable
556: and has not yet been marked.
557: Keep doing this until, in one pass, no blocks have been marked.
558: Then blocks_live and blocks_marked are identical and correct.
559: In addition, all jumps actually reachable have been marked. */
560:
561: while (something_marked)
562: {
563: something_marked = 0;
564: for (i = 0; i < n_basic_blocks; i++)
565: if (block_live[i] && !block_marked[i])
566: {
567: block_marked[i] = 1;
568: something_marked = 1;
569: if (i + 1 < n_basic_blocks && basic_block_drops_in[i + 1])
570: block_live[i + 1] = 1;
571: insn = basic_block_end[i];
572: if (GET_CODE (insn) == JUMP_INSN)
573: mark_label_ref (PATTERN (insn), insn, 0);
574: }
575: }
576:
577: /* Now delete the code for any basic blocks that can't be reached.
578: They can occur because jump_optimize does not recognize
579: unreachable loops as unreachable. */
580:
581: for (i = 0; i < n_basic_blocks; i++)
582: if (!block_live[i])
583: {
584: insn = basic_block_head[i];
585: while (1)
586: {
587: if (GET_CODE (insn) == BARRIER)
588: abort ();
589: if (GET_CODE (insn) != NOTE)
590: {
591: PUT_CODE (insn, NOTE);
592: NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
593: NOTE_SOURCE_FILE (insn) = 0;
594: }
595: if (insn == basic_block_end[i])
596: {
597: /* BARRIERs are between basic blocks, not part of one.
598: Delete a BARRIER if the preceding jump is deleted.
599: We cannot alter a BARRIER into a NOTE
600: because it is too short; but we can really delete
601: it because it is not part of a basic block. */
602: if (NEXT_INSN (insn) != 0
603: && GET_CODE (NEXT_INSN (insn)) == BARRIER)
604: delete_insn (NEXT_INSN (insn));
605: break;
606: }
607: insn = NEXT_INSN (insn);
608: }
609: /* Each time we delete some basic blocks,
610: see if there is a jump around them that is
611: being turned into a no-op. If so, delete it. */
612:
613: if (block_live[i - 1])
614: {
615: register int j;
616: for (j = i; j < n_basic_blocks; j++)
617: if (block_live[j])
618: {
619: rtx label;
620: insn = basic_block_end[i - 1];
621: if (GET_CODE (insn) == JUMP_INSN
622: /* An unconditional jump is the only possibility
623: we must check for, since a conditional one
624: would make these blocks live. */
625: && simplejump_p (insn)
626: && (label = XEXP (SET_SRC (PATTERN (insn)), 0), 1)
627: && INSN_UID (label) != 0
628: && BLOCK_NUM (label) == j)
629: {
630: PUT_CODE (insn, NOTE);
631: NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
632: NOTE_SOURCE_FILE (insn) = 0;
633: if (GET_CODE (NEXT_INSN (insn)) != BARRIER)
634: abort ();
635: delete_insn (NEXT_INSN (insn));
636: }
637: break;
638: }
639: }
640: }
641: }
642: }
643:
644: /* Check expression X for label references;
645: if one is found, add INSN to the label's chain of references.
646:
647: CHECKDUP means check for and avoid creating duplicate references
648: from the same insn. Such duplicates do no serious harm but
649: can slow life analysis. CHECKDUP is set only when duplicates
650: are likely. */
651:
652: static void
653: mark_label_ref (x, insn, checkdup)
654: rtx x, insn;
655: int checkdup;
656: {
657: register RTX_CODE code;
658: register int i;
659: register char *fmt;
660:
661: /* We can be called with NULL when scanning label_value_list. */
662: if (x == 0)
663: return;
664:
665: code = GET_CODE (x);
666: if (code == LABEL_REF)
667: {
668: register rtx label = XEXP (x, 0);
669: register rtx y;
670: if (GET_CODE (label) != CODE_LABEL)
671: abort ();
672: /* If the label was never emitted, this insn is junk,
673: but avoid a crash trying to refer to BLOCK_NUM (label).
674: This can happen as a result of a syntax error
675: and a diagnostic has already been printed. */
676: if (INSN_UID (label) == 0)
677: return;
678: CONTAINING_INSN (x) = insn;
679: /* if CHECKDUP is set, check for duplicate ref from same insn
680: and don't insert. */
681: if (checkdup)
682: for (y = LABEL_REFS (label); y != label; y = LABEL_NEXTREF (y))
683: if (CONTAINING_INSN (y) == insn)
684: return;
685: LABEL_NEXTREF (x) = LABEL_REFS (label);
686: LABEL_REFS (label) = x;
687: block_live_static[BLOCK_NUM (label)] = 1;
688: return;
689: }
690:
691: fmt = GET_RTX_FORMAT (code);
692: for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
693: {
694: if (fmt[i] == 'e')
695: mark_label_ref (XEXP (x, i), insn, 0);
696: if (fmt[i] == 'E')
697: {
698: register int j;
699: for (j = 0; j < XVECLEN (x, i); j++)
700: mark_label_ref (XVECEXP (x, i, j), insn, 1);
701: }
702: }
703: }
704:
705: /* Determine which registers are live at the start of each
706: basic block of the function whose first insn is F.
707: NREGS is the number of registers used in F.
708: We allocate the vector basic_block_live_at_start
709: and the regsets that it points to, and fill them with the data.
710: regset_size and regset_bytes are also set here. */
711:
712: static void
713: life_analysis (f, nregs)
714: rtx f;
715: int nregs;
716: {
717: register regset tem;
718: int first_pass;
719: int changed;
720: /* For each basic block, a bitmask of regs
721: live on exit from the block. */
722: regset *basic_block_live_at_end;
723: /* For each basic block, a bitmask of regs
724: live on entry to a successor-block of this block.
725: If this does not match basic_block_live_at_end,
726: that must be updated, and the block must be rescanned. */
727: regset *basic_block_new_live_at_end;
728: /* For each basic block, a bitmask of regs
729: whose liveness at the end of the basic block
730: can make a difference in which regs are live on entry to the block.
731: These are the regs that are set within the basic block,
732: possibly excluding those that are used after they are set. */
733: regset *basic_block_significant;
734: register int i;
735: rtx insn;
736:
737: struct obstack flow_obstack;
738:
739: gcc_obstack_init (&flow_obstack);
740:
741: max_regno = nregs;
742:
743: bzero (regs_ever_live, sizeof regs_ever_live);
744:
745: /* Allocate and zero out many data structures
746: that will record the data from lifetime analysis. */
747:
748: allocate_for_life_analysis ();
749:
750: reg_next_use = (rtx *) alloca (nregs * sizeof (rtx));
751: bzero (reg_next_use, nregs * sizeof (rtx));
752:
753: /* Set up several regset-vectors used internally within this function.
754: Their meanings are documented above, with their declarations. */
755:
756: basic_block_live_at_end = (regset *) alloca (n_basic_blocks * sizeof (regset));
757: /* Don't use alloca since that leads to a crash rather than an error message
758: if there isn't enough space.
759: Don't use oballoc since we may need to allocate other things during
760: this function on the temporary obstack. */
761: tem = (regset) obstack_alloc (&flow_obstack, n_basic_blocks * regset_bytes);
762: bzero (tem, n_basic_blocks * regset_bytes);
763: init_regset_vector (basic_block_live_at_end, tem, n_basic_blocks, regset_bytes);
764:
765: basic_block_new_live_at_end = (regset *) alloca (n_basic_blocks * sizeof (regset));
766: tem = (regset) obstack_alloc (&flow_obstack, n_basic_blocks * regset_bytes);
767: bzero (tem, n_basic_blocks * regset_bytes);
768: init_regset_vector (basic_block_new_live_at_end, tem, n_basic_blocks, regset_bytes);
769:
770: basic_block_significant = (regset *) alloca (n_basic_blocks * sizeof (regset));
771: tem = (regset) obstack_alloc (&flow_obstack, n_basic_blocks * regset_bytes);
772: bzero (tem, n_basic_blocks * regset_bytes);
773: init_regset_vector (basic_block_significant, tem, n_basic_blocks, regset_bytes);
774:
775: /* Record which insns refer to any volatile memory
776: or for any reason can't be deleted just because they are dead stores.
777: Also, delete any insns that copy a register to itself. */
778:
779: for (insn = f; insn; insn = NEXT_INSN (insn))
780: {
781: enum rtx_code code1 = GET_CODE (insn);
782: if (code1 == CALL_INSN)
783: INSN_VOLATILE (insn) = 1;
784: else if (code1 == INSN || code1 == JUMP_INSN)
785: {
786: /* Delete (in effect) any obvious no-op moves. */
787: if (GET_CODE (PATTERN (insn)) == SET
788: && GET_CODE (SET_DEST (PATTERN (insn))) == REG
789: && GET_CODE (SET_SRC (PATTERN (insn))) == REG
790: && REGNO (SET_DEST (PATTERN (insn))) ==
791: REGNO (SET_SRC (PATTERN (insn)))
792: /* Insns carrying these notes are useful later on. */
793: && ! find_reg_note (insn, REG_EQUAL, 0))
794: {
795: PUT_CODE (insn, NOTE);
796: NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
797: NOTE_SOURCE_FILE (insn) = 0;
798: }
799: else if (GET_CODE (PATTERN (insn)) == PARALLEL)
800: {
801: /* If nothing but SETs of registers to themselves,
802: this insn can also be deleted. */
803: for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++)
804: {
805: rtx tem = XVECEXP (PATTERN (insn), 0, i);
806:
807: if (GET_CODE (tem) == USE
808: || GET_CODE (tem) == CLOBBER)
809: continue;
810:
811: if (GET_CODE (tem) != SET
812: || GET_CODE (SET_DEST (tem)) != REG
813: || GET_CODE (SET_SRC (tem)) != REG
814: || REGNO (SET_DEST (tem)) != REGNO (SET_SRC (tem)))
815: break;
816: }
817:
818: if (i == XVECLEN (PATTERN (insn), 0)
819: /* Insns carrying these notes are useful later on. */
820: && ! find_reg_note (insn, REG_EQUAL, 0))
821: {
822: PUT_CODE (insn, NOTE);
823: NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
824: NOTE_SOURCE_FILE (insn) = 0;
825: }
826: else
827: INSN_VOLATILE (insn) = volatile_refs_p (PATTERN (insn));
828: }
829: else if (GET_CODE (PATTERN (insn)) != USE)
830: INSN_VOLATILE (insn) = volatile_refs_p (PATTERN (insn));
831: /* A SET that makes space on the stack cannot be dead.
832: (Such SETs occur only for allocating variable-size data,
833: so they will always have a PLUS or MINUS according to the
834: direction of stack growth.)
835: Even if this function never uses this stack pointer value,
836: signal handlers do! */
837: else if (code1 == INSN && GET_CODE (PATTERN (insn)) == SET
838: && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
839: #ifdef STACK_GROWS_DOWNWARD
840: && GET_CODE (SET_SRC (PATTERN (insn))) == MINUS
841: #else
842: && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
843: #endif
844: && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx)
845: INSN_VOLATILE (insn) = 1;
846: }
847: }
848:
849: if (n_basic_blocks > 0)
850: #ifdef EXIT_IGNORE_STACK
851: if (! EXIT_IGNORE_STACK
852: || (! FRAME_POINTER_REQUIRED && flag_omit_frame_pointer))
853: #endif
854: {
855: /* If exiting needs the right stack value,
856: consider the stack pointer live at the end of the function. */
857: basic_block_live_at_end[n_basic_blocks - 1]
858: [STACK_POINTER_REGNUM / REGSET_ELT_BITS]
859: |= 1 << (STACK_POINTER_REGNUM % REGSET_ELT_BITS);
860: basic_block_new_live_at_end[n_basic_blocks - 1]
861: [STACK_POINTER_REGNUM / REGSET_ELT_BITS]
862: |= 1 << (STACK_POINTER_REGNUM % REGSET_ELT_BITS);
863: }
864:
865: /* Mark all global registers as being live at the end of the function
866: since they may be referenced by our caller. */
867:
868: if (n_basic_blocks > 0)
869: for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
870: if (global_regs[i])
871: {
872: basic_block_live_at_end[n_basic_blocks - 1]
873: [i / REGSET_ELT_BITS] |= 1 << (i % REGSET_ELT_BITS);
874: basic_block_new_live_at_end[n_basic_blocks - 1]
875: [i / REGSET_ELT_BITS] |= 1 << (i % REGSET_ELT_BITS);
876: }
877:
878: /* Propagate life info through the basic blocks
879: around the graph of basic blocks.
880:
881: This is a relaxation process: each time a new register
882: is live at the end of the basic block, we must scan the block
883: to determine which registers are, as a consequence, live at the beginning
884: of that block. These registers must then be marked live at the ends
885: of all the blocks that can transfer control to that block.
886: The process continues until it reaches a fixed point. */
887:
888: first_pass = 1;
889: changed = 1;
890: while (changed)
891: {
892: changed = 0;
893: for (i = n_basic_blocks - 1; i >= 0; i--)
894: {
895: int consider = first_pass;
896: int must_rescan = first_pass;
897: register int j;
898:
899: if (!first_pass)
900: {
901: /* Set CONSIDER if this block needs thinking about at all
902: (that is, if the regs live now at the end of it
903: are not the same as were live at the end of it when
904: we last thought about it).
905: Set must_rescan if it needs to be thought about
906: instruction by instruction (that is, if any additional
907: reg that is live at the end now but was not live there before
908: is one of the significant regs of this basic block). */
909:
910: for (j = 0; j < regset_size; j++)
911: {
912: register int x = (basic_block_new_live_at_end[i][j]
913: & ~basic_block_live_at_end[i][j]);
914: if (x)
915: consider = 1;
916: if (x & basic_block_significant[i][j])
917: {
918: must_rescan = 1;
919: consider = 1;
920: break;
921: }
922: }
923:
924: if (! consider)
925: continue;
926: }
927:
928: /* The live_at_start of this block may be changing,
929: so another pass will be required after this one. */
930: changed = 1;
931:
932: if (! must_rescan)
933: {
934: /* No complete rescan needed;
935: just record those variables newly known live at end
936: as live at start as well. */
937: for (j = 0; j < regset_size; j++)
938: {
939: register int x = basic_block_new_live_at_end[i][j]
940: & ~basic_block_live_at_end[i][j];
941: basic_block_live_at_start[i][j] |= x;
942: basic_block_live_at_end[i][j] |= x;
943: }
944: }
945: else
946: {
947: /* Update the basic_block_live_at_start
948: by propagation backwards through the block. */
949: bcopy (basic_block_new_live_at_end[i],
950: basic_block_live_at_end[i], regset_bytes);
951: bcopy (basic_block_live_at_end[i],
952: basic_block_live_at_start[i], regset_bytes);
953: propagate_block (basic_block_live_at_start[i],
954: basic_block_head[i], basic_block_end[i], 0,
955: first_pass ? basic_block_significant[i] : 0,
956: i);
957: }
958:
959: {
960: register rtx jump, head;
961: /* Update the basic_block_new_live_at_end's of the block
962: that falls through into this one (if any). */
963: head = basic_block_head[i];
964: jump = PREV_INSN (head);
965: if (basic_block_drops_in[i])
966: {
967: register int from_block = BLOCK_NUM (jump);
968: register int j;
969: for (j = 0; j < regset_size; j++)
970: basic_block_new_live_at_end[from_block][j]
971: |= basic_block_live_at_start[i][j];
972: }
973: /* Update the basic_block_new_live_at_end's of
974: all the blocks that jump to this one. */
975: if (GET_CODE (head) == CODE_LABEL)
976: for (jump = LABEL_REFS (head);
977: jump != head;
978: jump = LABEL_NEXTREF (jump))
979: {
980: register int from_block = BLOCK_NUM (CONTAINING_INSN (jump));
981: register int j;
982: for (j = 0; j < regset_size; j++)
983: basic_block_new_live_at_end[from_block][j]
984: |= basic_block_live_at_start[i][j];
985: }
986: }
987: #ifdef USE_C_ALLOCA
988: alloca (0);
989: #endif
990: }
991: first_pass = 0;
992: }
993:
994: /* The only pseudos that are live at the beginning of the function are
995: those that were not set anywhere in the function. local-alloc doesn't
996: know how to handle these correctly, so mark them as not local to any
997: one basic block. */
998:
999: if (n_basic_blocks > 0)
1000: for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
1001: if (basic_block_live_at_start[0][i / REGSET_ELT_BITS]
1002: & (1 << (i % REGSET_ELT_BITS)))
1003: reg_basic_block[i] = REG_BLOCK_GLOBAL;
1004:
1005: /* Now the life information is accurate.
1006: Make one more pass over each basic block
1007: to delete dead stores, create autoincrement addressing
1008: and record how many times each register is used, is set, or dies.
1009:
1010: To save time, we operate directly in basic_block_live_at_end[i],
1011: thus destroying it (in fact, converting it into a copy of
1012: basic_block_live_at_start[i]). This is ok now because
1013: basic_block_live_at_end[i] is no longer used past this point. */
1014:
1015: max_scratch = 0;
1016:
1017: for (i = 0; i < n_basic_blocks; i++)
1018: {
1019: propagate_block (basic_block_live_at_end[i],
1020: basic_block_head[i], basic_block_end[i], 1, 0, i);
1021: #ifdef USE_C_ALLOCA
1022: alloca (0);
1023: #endif
1024: }
1025:
1026: #if 0
1027: /* Something live during a setjmp should not be put in a register
1028: on certain machines which restore regs from stack frames
1029: rather than from the jmpbuf.
1030: But we don't need to do this for the user's variables, since
1031: ANSI says only volatile variables need this. */
1032: #ifdef LONGJMP_RESTORE_FROM_STACK
1033: for (i = FIRST_PSEUDO_REGISTER; i < nregs; i++)
1034: if (regs_live_at_setjmp[i / REGSET_ELT_BITS] & (1 << (i % REGSET_ELT_BITS))
1035: && regno_reg_rtx[i] != 0 && ! REG_USERVAR_P (regno_reg_rtx[i]))
1036: {
1037: reg_live_length[i] = -1;
1038: reg_basic_block[i] = -1;
1039: }
1040: #endif
1041: #endif
1042:
1043: /* We have a problem with any pseudoreg that
1044: lives across the setjmp. ANSI says that if a
1045: user variable does not change in value
1046: between the setjmp and the longjmp, then the longjmp preserves it.
1047: This includes longjmp from a place where the pseudo appears dead.
1048: (In principle, the value still exists if it is in scope.)
1049: If the pseudo goes in a hard reg, some other value may occupy
1050: that hard reg where this pseudo is dead, thus clobbering the pseudo.
1051: Conclusion: such a pseudo must not go in a hard reg. */
1052: for (i = FIRST_PSEUDO_REGISTER; i < nregs; i++)
1053: if (regs_live_at_setjmp[i / REGSET_ELT_BITS] & (1 << (i % REGSET_ELT_BITS))
1054: && regno_reg_rtx[i] != 0)
1055: {
1056: reg_live_length[i] = -1;
1057: reg_basic_block[i] = -1;
1058: }
1059:
1060: obstack_free (&flow_obstack, 0);
1061: }
1062:
1063: /* Subroutines of life analysis. */
1064:
1065: /* Allocate the permanent data structures that represent the results
1066: of life analysis. Not static since used also for stupid life analysis. */
1067:
1068: void
1069: allocate_for_life_analysis ()
1070: {
1071: register int i;
1072: register regset tem;
1073:
1074: regset_size = ((max_regno + REGSET_ELT_BITS - 1) / REGSET_ELT_BITS);
1075: regset_bytes = regset_size * sizeof (*(regset)0);
1076:
1077: reg_n_refs = (int *) oballoc (max_regno * sizeof (int));
1078: bzero (reg_n_refs, max_regno * sizeof (int));
1079:
1080: reg_n_sets = (short *) oballoc (max_regno * sizeof (short));
1081: bzero (reg_n_sets, max_regno * sizeof (short));
1082:
1083: reg_n_deaths = (short *) oballoc (max_regno * sizeof (short));
1084: bzero (reg_n_deaths, max_regno * sizeof (short));
1085:
1086: reg_live_length = (int *) oballoc (max_regno * sizeof (int));
1087: bzero (reg_live_length, max_regno * sizeof (int));
1088:
1089: reg_n_calls_crossed = (int *) oballoc (max_regno * sizeof (int));
1090: bzero (reg_n_calls_crossed, max_regno * sizeof (int));
1091:
1092: reg_basic_block = (short *) oballoc (max_regno * sizeof (short));
1093: for (i = 0; i < max_regno; i++)
1094: reg_basic_block[i] = REG_BLOCK_UNKNOWN;
1095:
1096: basic_block_live_at_start = (regset *) oballoc (n_basic_blocks * sizeof (regset));
1097: tem = (regset) oballoc (n_basic_blocks * regset_bytes);
1098: bzero (tem, n_basic_blocks * regset_bytes);
1099: init_regset_vector (basic_block_live_at_start, tem, n_basic_blocks, regset_bytes);
1100:
1101: regs_live_at_setjmp = (regset) oballoc (regset_bytes);
1102: bzero (regs_live_at_setjmp, regset_bytes);
1103: }
1104:
1105: /* Make each element of VECTOR point at a regset,
1106: taking the space for all those regsets from SPACE.
1107: SPACE is of type regset, but it is really as long as NELTS regsets.
1108: BYTES_PER_ELT is the number of bytes in one regset. */
1109:
1110: static void
1111: init_regset_vector (vector, space, nelts, bytes_per_elt)
1112: regset *vector;
1113: regset space;
1114: int nelts;
1115: int bytes_per_elt;
1116: {
1117: register int i;
1118: register regset p = space;
1119:
1120: for (i = 0; i < nelts; i++)
1121: {
1122: vector[i] = p;
1123: p += bytes_per_elt / sizeof (*p);
1124: }
1125: }
1126:
1127: /* Compute the registers live at the beginning of a basic block
1128: from those live at the end.
1129:
1130: When called, OLD contains those live at the end.
1131: On return, it contains those live at the beginning.
1132: FIRST and LAST are the first and last insns of the basic block.
1133:
1134: FINAL is nonzero if we are doing the final pass which is not
1135: for computing the life info (since that has already been done)
1136: but for acting on it. On this pass, we delete dead stores,
1137: set up the logical links and dead-variables lists of instructions,
1138: and merge instructions for autoincrement and autodecrement addresses.
1139:
1140: SIGNIFICANT is nonzero only the first time for each basic block.
1141: If it is nonzero, it points to a regset in which we store
1142: a 1 for each register that is set within the block.
1143:
1144: BNUM is the number of the basic block. */
1145:
1146: static void
1147: propagate_block (old, first, last, final, significant, bnum)
1148: register regset old;
1149: rtx first;
1150: rtx last;
1151: int final;
1152: regset significant;
1153: int bnum;
1154: {
1155: register rtx insn;
1156: rtx prev;
1157: regset live;
1158: regset dead;
1159:
1160: /* The following variables are used only if FINAL is nonzero. */
1161: /* This vector gets one element for each reg that has been live
1162: at any point in the basic block that has been scanned so far.
1163: SOMETIMES_MAX says how many elements are in use so far.
1164: In each element, OFFSET is the byte-number within a regset
1165: for the register described by the element, and BIT is a mask
1166: for that register's bit within the byte. */
1167: register struct foo { short offset; short bit; } *regs_sometimes_live;
1168: int sometimes_max = 0;
1169: /* This regset has 1 for each reg that we have seen live so far.
1170: It and REGS_SOMETIMES_LIVE are updated together. */
1171: regset maxlive;
1172:
1173: /* The loop depth may change in the middle of a basic block. Since we
1174: scan from end to beginning, we start with the depth at the end of the
1175: current basic block, and adjust as we pass ends and starts of loops. */
1176: loop_depth = basic_block_loop_depth[bnum];
1177:
1178: dead = (regset) alloca (regset_bytes);
1179: live = (regset) alloca (regset_bytes);
1180:
1181: cc0_live = 0;
1182: last_mem_set = 0;
1183:
1184: /* Include any notes at the end of the block in the scan.
1185: This is in case the block ends with a call to setjmp. */
1186:
1187: while (NEXT_INSN (last) != 0 && GET_CODE (NEXT_INSN (last)) == NOTE)
1188: {
1189: /* Look for loop boundaries, we are going forward here. */
1190: last = NEXT_INSN (last);
1191: if (NOTE_LINE_NUMBER (last) == NOTE_INSN_LOOP_BEG)
1192: loop_depth++;
1193: else if (NOTE_LINE_NUMBER (last) == NOTE_INSN_LOOP_END)
1194: loop_depth--;
1195: }
1196:
1197: if (final)
1198: {
1199: register int i, offset, bit;
1200:
1201: num_scratch = 0;
1202: maxlive = (regset) alloca (regset_bytes);
1203: bcopy (old, maxlive, regset_bytes);
1204: regs_sometimes_live
1205: = (struct foo *) alloca (max_regno * sizeof (struct foo));
1206:
1207: /* Process the regs live at the end of the block.
1208: Enter them in MAXLIVE and REGS_SOMETIMES_LIVE.
1209: Also mark them as not local to any one basic block. */
1210:
1211: for (offset = 0, i = 0; offset < regset_size; offset++)
1212: for (bit = 1; bit; bit <<= 1, i++)
1213: {
1214: if (i == max_regno)
1215: break;
1216: if (old[offset] & bit)
1217: {
1218: reg_basic_block[i] = REG_BLOCK_GLOBAL;
1219: regs_sometimes_live[sometimes_max].offset = offset;
1220: regs_sometimes_live[sometimes_max].bit = i % REGSET_ELT_BITS;
1221: sometimes_max++;
1222: }
1223: }
1224: }
1225:
1226: /* Scan the block an insn at a time from end to beginning. */
1227:
1228: for (insn = last; ; insn = prev)
1229: {
1230: prev = PREV_INSN (insn);
1231:
1232: /* Look for loop boundaries, remembering that we are going backwards. */
1233: if (GET_CODE (insn) == NOTE
1234: && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
1235: loop_depth++;
1236: else if (GET_CODE (insn) == NOTE
1237: && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
1238: loop_depth--;
1239:
1240: /* If we have LOOP_DEPTH == 0, there has been a bookkeeping error.
1241: Abort now rather than setting register status incorrectly. */
1242: if (loop_depth == 0)
1243: abort ();
1244:
1245: /* If this is a call to `setjmp' et al,
1246: warn if any non-volatile datum is live. */
1247:
1248: if (final && GET_CODE (insn) == NOTE
1249: && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
1250: {
1251: int i;
1252: for (i = 0; i < regset_size; i++)
1253: regs_live_at_setjmp[i] |= old[i];
1254: }
1255:
1256: /* Update the life-status of regs for this insn.
1257: First DEAD gets which regs are set in this insn
1258: then LIVE gets which regs are used in this insn.
1259: Then the regs live before the insn
1260: are those live after, with DEAD regs turned off,
1261: and then LIVE regs turned on. */
1262:
1263: if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
1264: {
1265: register int i;
1266: rtx note = find_reg_note (insn, REG_RETVAL, 0);
1267: int insn_is_dead
1268: = (insn_dead_p (PATTERN (insn), old, 0)
1269: /* Don't delete something that refers to volatile storage! */
1270: && ! INSN_VOLATILE (insn));
1271: int libcall_is_dead
1272: = (insn_is_dead && note != 0
1273: && libcall_dead_p (PATTERN (insn), old, note, insn));
1274:
1275: /* If an instruction consists of just dead store(s) on final pass,
1276: "delete" it by turning it into a NOTE of type NOTE_INSN_DELETED.
1277: We could really delete it with delete_insn, but that
1278: can cause trouble for first or last insn in a basic block. */
1279: if (final && insn_is_dead)
1280: {
1281: PUT_CODE (insn, NOTE);
1282: NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
1283: NOTE_SOURCE_FILE (insn) = 0;
1284:
1.1.1.2 root 1285: /* CC0 is now known to be dead. Either this insn used it,
1286: in which case it doesn't anymore, or clobbered it,
1287: so the next insn can't use it. */
1288: cc0_live = 0;
1289:
1.1 root 1290: /* If this insn is copying the return value from a library call,
1291: delete the entire library call. */
1292: if (libcall_is_dead)
1293: {
1294: rtx first = XEXP (note, 0);
1295: rtx p = insn;
1296: while (INSN_DELETED_P (first))
1297: first = NEXT_INSN (first);
1298: while (p != first)
1299: {
1300: p = PREV_INSN (p);
1301: PUT_CODE (p, NOTE);
1302: NOTE_LINE_NUMBER (p) = NOTE_INSN_DELETED;
1303: NOTE_SOURCE_FILE (p) = 0;
1304: }
1305: }
1306: goto flushed;
1307: }
1308:
1309: for (i = 0; i < regset_size; i++)
1310: {
1311: dead[i] = 0; /* Faster than bzero here */
1312: live[i] = 0; /* since regset_size is usually small */
1313: }
1314:
1315: /* See if this is an increment or decrement that can be
1316: merged into a following memory address. */
1317: #ifdef AUTO_INC_DEC
1318: {
1319: register rtx x = PATTERN (insn);
1320: /* Does this instruction increment or decrement a register? */
1321: if (final && GET_CODE (x) == SET
1322: && GET_CODE (SET_DEST (x)) == REG
1323: && (GET_CODE (SET_SRC (x)) == PLUS
1324: || GET_CODE (SET_SRC (x)) == MINUS)
1325: && XEXP (SET_SRC (x), 0) == SET_DEST (x)
1326: && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
1327: /* Ok, look for a following memory ref we can combine with.
1328: If one is found, change the memory ref to a PRE_INC
1329: or PRE_DEC, cancel this insn, and return 1.
1330: Return 0 if nothing has been done. */
1331: && try_pre_increment_1 (insn))
1332: goto flushed;
1333: }
1334: #endif /* AUTO_INC_DEC */
1335:
1336: /* If this is not the final pass, and this insn is copying the
1337: value of a library call and it's dead, don't scan the
1338: insns that perform the library call, so that the call's
1339: arguments are not marked live. */
1340: if (libcall_is_dead)
1341: {
1342: /* Mark the dest reg as `significant'. */
1343: mark_set_regs (old, dead, PATTERN (insn), 0, significant);
1344:
1345: insn = XEXP (note, 0);
1346: prev = PREV_INSN (insn);
1347: }
1348: else if (GET_CODE (PATTERN (insn)) == SET
1349: && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
1350: && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
1351: && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
1352: && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
1353: /* We have an insn to pop a constant amount off the stack.
1354: (Such insns use PLUS regardless of the direction of the stack,
1355: and any insn to adjust the stack by a constant is always a pop.)
1356: These insns, if not dead stores, have no effect on life. */
1357: ;
1358: else
1359: {
1360: /* LIVE gets the regs used in INSN;
1361: DEAD gets those set by it. Dead insns don't make anything
1362: live. */
1363:
1364: mark_set_regs (old, dead, PATTERN (insn), final ? insn : 0,
1365: significant);
1366:
1367: /* If an insn doesn't use CC0, it becomes dead since we
1368: assume that every insn clobbers it. So show it dead here;
1369: mark_used_regs will set it live if it is referenced. */
1370: cc0_live = 0;
1371:
1372: if (! insn_is_dead)
1373: mark_used_regs (old, live, PATTERN (insn), final, insn);
1374:
1375: /* Sometimes we may have inserted something before INSN (such as
1376: a move) when we make an auto-inc. So ensure we will scan
1377: those insns. */
1378: #ifdef AUTO_INC_DEC
1379: prev = PREV_INSN (insn);
1380: #endif
1381:
1382: if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
1383: {
1384: register int i;
1385:
1386: /* Each call clobbers all call-clobbered regs that are not
1387: global. Note that the function-value reg is a
1388: call-clobbered reg, and mark_set_regs has already had
1389: a chance to handle it. */
1390:
1391: for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1392: if (call_used_regs[i] && ! global_regs[i])
1393: dead[i / REGSET_ELT_BITS]
1394: |= (1 << (i % REGSET_ELT_BITS));
1395:
1396: /* The stack ptr is used (honorarily) by a CALL insn. */
1397: live[STACK_POINTER_REGNUM / REGSET_ELT_BITS]
1398: |= (1 << (STACK_POINTER_REGNUM % REGSET_ELT_BITS));
1399:
1400: /* Calls may also reference any of the global registers,
1401: so they are made live. */
1402:
1403: for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1404: if (global_regs[i])
1405: live[i / REGSET_ELT_BITS]
1406: |= (1 << (i % REGSET_ELT_BITS));
1407:
1408: /* Calls also clobber memory. */
1409: last_mem_set = 0;
1410: }
1411:
1412: /* Update OLD for the registers used or set. */
1413: for (i = 0; i < regset_size; i++)
1414: {
1415: old[i] &= ~dead[i];
1416: old[i] |= live[i];
1417: }
1418:
1419: if (GET_CODE (insn) == CALL_INSN && final)
1420: {
1421: /* Any regs live at the time of a call instruction
1422: must not go in a register clobbered by calls.
1423: Find all regs now live and record this for them. */
1424:
1425: register struct foo *p = regs_sometimes_live;
1426:
1427: for (i = 0; i < sometimes_max; i++, p++)
1428: if (old[p->offset] & (1 << p->bit))
1429: reg_n_calls_crossed[p->offset * REGSET_ELT_BITS + p->bit]+= 1;
1430: }
1431: }
1432:
1433: /* On final pass, add any additional sometimes-live regs
1434: into MAXLIVE and REGS_SOMETIMES_LIVE.
1435: Also update counts of how many insns each reg is live at. */
1436:
1437: if (final)
1438: {
1439: for (i = 0; i < regset_size; i++)
1440: {
1441: register int diff = live[i] & ~maxlive[i];
1442:
1443: if (diff)
1444: {
1445: register int regno;
1446: maxlive[i] |= diff;
1447: for (regno = 0; diff && regno < REGSET_ELT_BITS; regno++)
1448: if (diff & (1 << regno))
1449: {
1450: regs_sometimes_live[sometimes_max].offset = i;
1451: regs_sometimes_live[sometimes_max].bit = regno;
1452: diff &= ~ (1 << regno);
1453: sometimes_max++;
1454: }
1455: }
1456: }
1457:
1458: {
1459: register struct foo *p = regs_sometimes_live;
1460: for (i = 0; i < sometimes_max; i++, p++)
1461: {
1462: if (old[p->offset] & (1 << p->bit))
1463: reg_live_length[p->offset * REGSET_ELT_BITS + p->bit]++;
1464: }
1465: }
1466: }
1467: }
1468: flushed: ;
1469: if (insn == first)
1470: break;
1471: }
1472:
1473: if (num_scratch > max_scratch)
1474: max_scratch = num_scratch;
1475: }
1476:
1477: /* Return 1 if X (the body of an insn, or part of it) is just dead stores
1478: (SET expressions whose destinations are registers dead after the insn).
1479: NEEDED is the regset that says which regs are alive after the insn.
1480:
1481: Unless CALL_OK is non-zero, an insn is needed if it contains a CALL. */
1482:
1483: static int
1484: insn_dead_p (x, needed, call_ok)
1485: rtx x;
1486: regset needed;
1487: int call_ok;
1488: {
1489: register RTX_CODE code = GET_CODE (x);
1490: /* If setting something that's a reg or part of one,
1491: see if that register's altered value will be live. */
1492:
1493: if (code == SET)
1494: {
1495: register rtx r = SET_DEST (x);
1496: /* A SET that is a subroutine call cannot be dead. */
1497: if (! call_ok && GET_CODE (SET_SRC (x)) == CALL)
1498: return 0;
1499:
1500: #ifdef HAVE_cc0
1501: if (GET_CODE (r) == CC0)
1502: return ! cc0_live;
1503: #endif
1504:
1505: if (GET_CODE (r) == MEM && last_mem_set && ! MEM_VOLATILE_P (r)
1506: && rtx_equal_p (r, last_mem_set))
1507: return 1;
1508:
1509: while (GET_CODE (r) == SUBREG
1510: || GET_CODE (r) == STRICT_LOW_PART
1511: || GET_CODE (r) == ZERO_EXTRACT
1512: || GET_CODE (r) == SIGN_EXTRACT)
1513: r = SUBREG_REG (r);
1514:
1515: if (GET_CODE (r) == REG)
1516: {
1517: register int regno = REGNO (r);
1518: register int offset = regno / REGSET_ELT_BITS;
1519: register int bit = 1 << (regno % REGSET_ELT_BITS);
1520:
1521: if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
1522: /* Make sure insns to set frame pointer aren't deleted. */
1523: || regno == FRAME_POINTER_REGNUM
1524: #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1525: /* Make sure insns to set arg pointer are never deleted
1526: (if the arg pointer isn't fixed, there will be a USE for
1527: it, so we can treat it normally). */
1528: || (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
1529: #endif
1530: || (needed[offset] & bit) != 0)
1531: return 0;
1532:
1533: /* If this is a hard register, verify that subsequent words are
1534: not needed. */
1535: if (regno < FIRST_PSEUDO_REGISTER)
1536: {
1537: int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
1538:
1539: while (--n > 0)
1540: if ((needed[(regno + n) / REGSET_ELT_BITS]
1541: & 1 << ((regno + n) % REGSET_ELT_BITS)) != 0)
1542: return 0;
1543: }
1544:
1545: return 1;
1546: }
1547: }
1548: /* If performing several activities,
1549: insn is dead if each activity is individually dead.
1550: Also, CLOBBERs and USEs can be ignored; a CLOBBER or USE
1551: that's inside a PARALLEL doesn't make the insn worth keeping. */
1552: else if (code == PARALLEL)
1553: {
1554: register int i = XVECLEN (x, 0);
1555: for (i--; i >= 0; i--)
1556: {
1557: rtx elt = XVECEXP (x, 0, i);
1558: if (!insn_dead_p (elt, needed, call_ok)
1559: && GET_CODE (elt) != CLOBBER
1560: && GET_CODE (elt) != USE)
1561: return 0;
1562: }
1563: return 1;
1564: }
1565: /* We do not check CLOBBER or USE here.
1566: An insn consisting of just a CLOBBER or just a USE
1567: should not be deleted. */
1568: return 0;
1569: }
1570:
1571: /* If X is the pattern of the last insn in a libcall, and assuming X is dead,
1572: return 1 if the entire library call is dead.
1573: This is true if X copies a register (hard or pseudo)
1574: and if the hard return reg of the call insn is dead.
1575: (The caller should have tested the destination of X already for death.)
1576:
1577: If this insn doesn't just copy a register, then we don't
1578: have an ordinary libcall. In that case, cse could not have
1579: managed to substitute the source for the dest later on,
1580: so we can assume the libcall is dead.
1581:
1582: NEEDED is the bit vector of pseudoregs live before this insn.
1583: NOTE is the REG_RETVAL note of the insn. INSN is the insn itself. */
1584:
1585: static int
1586: libcall_dead_p (x, needed, note, insn)
1587: rtx x;
1588: regset needed;
1589: rtx note;
1590: rtx insn;
1591: {
1592: register RTX_CODE code = GET_CODE (x);
1593:
1594: if (code == SET)
1595: {
1596: register rtx r = SET_SRC (x);
1597: if (GET_CODE (r) == REG)
1598: {
1599: rtx call = XEXP (note, 0);
1600: register int i;
1601:
1602: /* Find the call insn. */
1603: while (call != insn && GET_CODE (call) != CALL_INSN)
1604: call = NEXT_INSN (call);
1605:
1606: /* If there is none, do nothing special,
1607: since ordinary death handling can understand these insns. */
1608: if (call == insn)
1609: return 0;
1610:
1611: /* See if the hard reg holding the value is dead.
1612: If this is a PARALLEL, find the call within it. */
1613: call = PATTERN (call);
1614: if (GET_CODE (call) == PARALLEL)
1615: {
1616: for (i = XVECLEN (call, 0) - 1; i >= 0; i--)
1617: if (GET_CODE (XVECEXP (call, 0, i)) == SET
1618: && GET_CODE (SET_SRC (XVECEXP (call, 0, i))) == CALL)
1619: break;
1620:
1621: if (i < 0)
1622: abort ();
1623:
1624: call = XVECEXP (call, 0, i);
1625: }
1626:
1627: return insn_dead_p (call, needed, 1);
1628: }
1629: }
1630: return 1;
1631: }
1632:
1633: /* Return 1 if register REGNO was used before it was set.
1634: In other words, if it is live at function entry. */
1635:
1636: int
1637: regno_uninitialized (regno)
1638: int regno;
1639: {
1640: if (n_basic_blocks == 0)
1641: return 0;
1642:
1643: return (basic_block_live_at_start[0][regno / REGSET_ELT_BITS]
1644: & (1 << (regno % REGSET_ELT_BITS)));
1645: }
1646:
1647: /* 1 if register REGNO was alive at a place where `setjmp' was called
1648: and was set more than once or is an argument.
1649: Such regs may be clobbered by `longjmp'. */
1650:
1651: int
1652: regno_clobbered_at_setjmp (regno)
1653: int regno;
1654: {
1655: if (n_basic_blocks == 0)
1656: return 0;
1657:
1658: return ((reg_n_sets[regno] > 1
1659: || (basic_block_live_at_start[0][regno / REGSET_ELT_BITS]
1660: & (1 << (regno % REGSET_ELT_BITS))))
1661: && (regs_live_at_setjmp[regno / REGSET_ELT_BITS]
1662: & (1 << (regno % REGSET_ELT_BITS))));
1663: }
1664:
1665: /* Process the registers that are set within X.
1666: Their bits are set to 1 in the regset DEAD,
1667: because they are dead prior to this insn.
1668:
1669: If INSN is nonzero, it is the insn being processed
1670: and the fact that it is nonzero implies this is the FINAL pass
1671: in propagate_block. In this case, various info about register
1672: usage is stored, LOG_LINKS fields of insns are set up. */
1673:
1674: static void mark_set_1 ();
1675:
1676: static void
1677: mark_set_regs (needed, dead, x, insn, significant)
1678: regset needed;
1679: regset dead;
1680: rtx x;
1681: rtx insn;
1682: regset significant;
1683: {
1684: register RTX_CODE code = GET_CODE (x);
1685:
1686: if (code == SET || code == CLOBBER)
1687: mark_set_1 (needed, dead, x, insn, significant);
1688: else if (code == PARALLEL)
1689: {
1690: register int i;
1691: for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
1692: {
1693: code = GET_CODE (XVECEXP (x, 0, i));
1694: if (code == SET || code == CLOBBER)
1695: mark_set_1 (needed, dead, XVECEXP (x, 0, i), insn, significant);
1696: }
1697: }
1698: }
1699:
1700: /* Process a single SET rtx, X. */
1701:
1702: static void
1703: mark_set_1 (needed, dead, x, insn, significant)
1704: regset needed;
1705: regset dead;
1706: rtx x;
1707: rtx insn;
1708: regset significant;
1709: {
1710: register int regno;
1711: register rtx reg = SET_DEST (x);
1712:
1713: /* Modifying just one hardware register of a multi-reg value
1714: or just a byte field of a register
1715: does not mean the value from before this insn is now dead.
1716: But it does mean liveness of that register at the end of the block
1717: is significant.
1718:
1719: Within mark_set_1, however, we treat it as if the register is
1720: indeed modified. mark_used_regs will, however, also treat this
1721: register as being used. Thus, we treat these insns as setting a
1722: new value for the register as a function of its old value. This
1723: cases LOG_LINKS to be made appropriately and this will help combine. */
1724:
1725: while (GET_CODE (reg) == SUBREG || GET_CODE (reg) == ZERO_EXTRACT
1726: || GET_CODE (reg) == SIGN_EXTRACT
1727: || GET_CODE (reg) == STRICT_LOW_PART)
1728: reg = XEXP (reg, 0);
1729:
1730: /* If we are writing into memory or into a register mentioned in the
1731: address of the last thing stored into memory, show we don't know
1732: what the last store was. If we are writing memory, save the address
1733: unless it is volatile. */
1734: if (GET_CODE (reg) == MEM
1735: || (GET_CODE (reg) == REG
1736: && last_mem_set != 0 && reg_overlap_mentioned_p (reg, last_mem_set)))
1737: last_mem_set = 0;
1738:
1739: if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
1740: /* There are no REG_INC notes for SP, so we can't assume we'll see
1741: everything that invalidates it. To be safe, don't eliminate any
1742: stores though SP; none of them should be redundant anyway. */
1743: && ! reg_mentioned_p (stack_pointer_rtx, reg))
1744: last_mem_set = reg;
1745:
1746: if (GET_CODE (reg) == REG
1747: && (regno = REGNO (reg), regno != FRAME_POINTER_REGNUM)
1748: #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1749: && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
1750: #endif
1751: && ! (regno < FIRST_PSEUDO_REGISTER && global_regs[regno]))
1752: /* && regno != STACK_POINTER_REGNUM) -- let's try without this. */
1753: {
1754: register int offset = regno / REGSET_ELT_BITS;
1755: register int bit = 1 << (regno % REGSET_ELT_BITS);
1756: int all_needed = (needed[offset] & bit) != 0;
1757: int some_needed = (needed[offset] & bit) != 0;
1758:
1759: /* Mark it as a significant register for this basic block. */
1760: if (significant)
1761: significant[offset] |= bit;
1762:
1763: /* Mark it as as dead before this insn. */
1764: dead[offset] |= bit;
1765:
1766: /* A hard reg in a wide mode may really be multiple registers.
1767: If so, mark all of them just like the first. */
1768: if (regno < FIRST_PSEUDO_REGISTER)
1769: {
1770: int n;
1771:
1772: /* Nothing below is needed for the stack pointer; get out asap.
1773: Eg, log links aren't needed, since combine won't use them. */
1774: if (regno == STACK_POINTER_REGNUM)
1775: return;
1776:
1777: n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
1778: while (--n > 0)
1779: {
1780: if (significant)
1781: significant[(regno + n) / REGSET_ELT_BITS]
1782: |= 1 << ((regno + n) % REGSET_ELT_BITS);
1783: dead[(regno + n) / REGSET_ELT_BITS]
1784: |= 1 << ((regno + n) % REGSET_ELT_BITS);
1785: some_needed |= (needed[(regno + n) / REGSET_ELT_BITS]
1786: & 1 << ((regno + n) % REGSET_ELT_BITS));
1787: all_needed &= (needed[(regno + n) / REGSET_ELT_BITS]
1788: & 1 << ((regno + n) % REGSET_ELT_BITS));
1789: }
1790: }
1791: /* Additional data to record if this is the final pass. */
1792: if (insn)
1793: {
1794: register rtx y = reg_next_use[regno];
1795: register int blocknum = BLOCK_NUM (insn);
1796:
1797: /* If this is a hard reg, record this function uses the reg. */
1798:
1799: if (regno < FIRST_PSEUDO_REGISTER)
1800: {
1801: register int i;
1802: int endregno = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg));
1803:
1804: for (i = regno; i < endregno; i++)
1805: {
1806: regs_ever_live[i] = 1;
1807: reg_n_sets[i]++;
1808: }
1809: }
1810: else
1811: {
1812: /* Keep track of which basic blocks each reg appears in. */
1813:
1814: if (reg_basic_block[regno] == REG_BLOCK_UNKNOWN)
1815: reg_basic_block[regno] = blocknum;
1816: else if (reg_basic_block[regno] != blocknum)
1817: reg_basic_block[regno] = REG_BLOCK_GLOBAL;
1818:
1819: /* Count (weighted) references, stores, etc. This counts a
1820: register twice if it is modified, but that is correct. */
1821: reg_n_sets[regno]++;
1822:
1823: reg_n_refs[regno] += loop_depth;
1824:
1825: /* The insns where a reg is live are normally counted
1826: elsewhere, but we want the count to include the insn
1827: where the reg is set, and the normal counting mechanism
1828: would not count it. */
1829: reg_live_length[regno]++;
1830: }
1831:
1832: /* The next use is no longer "next", since a store intervenes. */
1833: reg_next_use[regno] = 0;
1834:
1835: if (all_needed)
1836: {
1837: /* Make a logical link from the next following insn
1838: that uses this register, back to this insn.
1839: The following insns have already been processed.
1840:
1841: We don't build a LOG_LINK for hard registers containing
1842: in ASM_OPERANDs. If these registers get replaced,
1843: we might wind up changing the semantics of the insn,
1844: even if reload can make what appear to be valid assignments
1845: later. */
1846: if (y && (BLOCK_NUM (y) == blocknum)
1847: && (regno >= FIRST_PSEUDO_REGISTER
1848: || asm_noperands (PATTERN (y)) < 0))
1849: LOG_LINKS (y)
1850: = gen_rtx (INSN_LIST, VOIDmode, insn, LOG_LINKS (y));
1851: }
1852: else if (! some_needed)
1853: {
1854: /* Note that dead stores have already been deleted when possible
1855: If we get here, we have found a dead store that cannot
1856: be eliminated (because the same insn does something useful).
1857: Indicate this by marking the reg being set as dying here. */
1858: REG_NOTES (insn)
1859: = gen_rtx (EXPR_LIST, REG_UNUSED, reg, REG_NOTES (insn));
1860: reg_n_deaths[REGNO (reg)]++;
1861: }
1862: else
1863: {
1864: /* This is a case where we have a multi-word hard register
1865: and some, but not all, of the words of the register are
1866: needed in subsequent insns. Write REG_UNUSED notes
1867: for those parts that were not needed. This case should
1868: be rare. */
1869:
1870: int i;
1871:
1872: for (i = HARD_REGNO_NREGS (regno, GET_MODE (reg)) - 1;
1873: i >= 0; i--)
1874: if ((needed[(regno + i) / REGSET_ELT_BITS]
1875: & 1 << ((regno + i) % REGSET_ELT_BITS)) == 0)
1876: REG_NOTES (insn)
1877: = gen_rtx (EXPR_LIST, REG_UNUSED,
1878: gen_rtx (REG, word_mode, regno + i),
1879: REG_NOTES (insn));
1880: }
1881: }
1882: }
1883:
1884: /* If this is the last pass and this is a SCRATCH, show it will be dying
1885: here and count it. */
1886: else if (GET_CODE (reg) == SCRATCH && insn != 0)
1887: {
1888: REG_NOTES (insn)
1889: = gen_rtx (EXPR_LIST, REG_UNUSED, reg, REG_NOTES (insn));
1890: num_scratch++;
1891: }
1892: }
1893:
1894: #ifdef AUTO_INC_DEC
1895:
1896: /* X is a MEM found in INSN. See if we can convert it into an auto-increment
1897: reference. */
1898:
1899: static void
1900: find_auto_inc (needed, x, insn)
1901: regset needed;
1902: rtx x;
1903: rtx insn;
1904: {
1905: rtx addr = XEXP (x, 0);
1906: int offset = 0;
1907:
1908: /* Here we detect use of an index register which might be good for
1909: postincrement, postdecrement, preincrement, or predecrement. */
1910:
1911: if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
1912: offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
1913:
1914: if (GET_CODE (addr) == REG)
1915: {
1916: register rtx y;
1917: register int size = GET_MODE_SIZE (GET_MODE (x));
1918: rtx use;
1919: rtx incr;
1920: int regno = REGNO (addr);
1921:
1922: /* Is the next use an increment that might make auto-increment? */
1923: incr = reg_next_use[regno];
1924: if (incr && GET_CODE (PATTERN (incr)) == SET
1925: && BLOCK_NUM (incr) == BLOCK_NUM (insn)
1926: /* Can't add side effects to jumps; if reg is spilled and
1927: reloaded, there's no way to store back the altered value. */
1928: && GET_CODE (insn) != JUMP_INSN
1929: && (y = SET_SRC (PATTERN (incr)), GET_CODE (y) == PLUS)
1930: && XEXP (y, 0) == addr
1931: && GET_CODE (XEXP (y, 1)) == CONST_INT
1932: && (0
1933: #ifdef HAVE_POST_INCREMENT
1934: || (INTVAL (XEXP (y, 1)) == size && offset == 0)
1935: #endif
1936: #ifdef HAVE_POST_DECREMENT
1937: || (INTVAL (XEXP (y, 1)) == - size && offset == 0)
1938: #endif
1939: #ifdef HAVE_PRE_INCREMENT
1940: || (INTVAL (XEXP (y, 1)) == size && offset == size)
1941: #endif
1942: #ifdef HAVE_PRE_DECREMENT
1943: || (INTVAL (XEXP (y, 1)) == - size && offset == - size)
1944: #endif
1945: )
1946: /* Make sure this reg appears only once in this insn. */
1947: && (use = find_use_as_address (PATTERN (insn), addr, offset),
1948: use != 0 && use != (rtx) 1))
1949: {
1950: int win = 0;
1951: rtx q = SET_DEST (PATTERN (incr));
1952:
1953: if (dead_or_set_p (incr, addr))
1954: win = 1;
1955: else if (GET_CODE (q) == REG && ! reg_used_between_p (q, insn, incr))
1956: {
1957: /* We have *p followed by q = p+size.
1958: Both p and q must be live afterward,
1959: and q must be dead before.
1960: Change it to q = p, ...*q..., q = q+size.
1961: Then fall into the usual case. */
1962: rtx insns, temp;
1963:
1964: start_sequence ();
1965: emit_move_insn (q, addr);
1966: insns = get_insns ();
1967: end_sequence ();
1968:
1969: /* If anything in INSNS have UID's that don't fit within the
1970: extra space we allocate earlier, we can't make this auto-inc.
1971: This should never happen. */
1972: for (temp = insns; temp; temp = NEXT_INSN (temp))
1973: {
1974: if (INSN_UID (temp) > max_uid_for_flow)
1975: return;
1976: BLOCK_NUM (temp) = BLOCK_NUM (insn);
1977: }
1978:
1979: emit_insns_before (insns, insn);
1980:
1981: if (basic_block_head[BLOCK_NUM (insn)] == insn)
1982: basic_block_head[BLOCK_NUM (insn)] = insns;
1983:
1984: XEXP (x, 0) = q;
1985: XEXP (y, 0) = q;
1986:
1987: /* INCR will become a NOTE and INSN won't contain a
1988: use of ADDR. If a use of ADDR was just placed in
1989: the insn before INSN, make that the next use.
1990: Otherwise, invalidate it. */
1991: if (GET_CODE (PREV_INSN (insn)) == INSN
1992: && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
1993: && SET_SRC (PATTERN (PREV_INSN (insn))) == addr)
1994: reg_next_use[regno] = PREV_INSN (insn);
1995: else
1996: reg_next_use[regno] = 0;
1997:
1998: addr = q;
1999: regno = REGNO (q);
2000: win = 1;
2001:
2002: /* REGNO is now used in INCR which is below INSN, but
2003: it previously wasn't live here. If we don't mark
2004: it as needed, we'll put a REG_DEAD note for it
2005: on this insn, which is incorrect. */
2006: needed[regno / REGSET_ELT_BITS]
2007: |= 1 << (regno % REGSET_ELT_BITS);
2008:
2009: /* If there are any calls between INSN and INCR, show
2010: that REGNO now crosses them. */
2011: for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
2012: if (GET_CODE (temp) == CALL_INSN)
2013: reg_n_calls_crossed[regno]++;
2014: }
2015:
2016: if (win)
2017: {
2018: /* We have found a suitable auto-increment: do POST_INC around
2019: the register here, and patch out the increment instruction
2020: that follows. */
2021: XEXP (x, 0) = gen_rtx ((INTVAL (XEXP (y, 1)) == size
2022: ? (offset ? PRE_INC : POST_INC)
2023: : (offset ? PRE_DEC : POST_DEC)),
2024: Pmode, addr);
2025:
2026: /* Record that this insn has an implicit side effect. */
2027: REG_NOTES (insn)
2028: = gen_rtx (EXPR_LIST, REG_INC, addr, REG_NOTES (insn));
2029:
2030: /* Modify the old increment-insn to simply copy
2031: the already-incremented value of our register. */
2032: SET_SRC (PATTERN (incr)) = addr;
2033: /* Indicate insn must be re-recognized. */
2034: INSN_CODE (incr) = -1;
2035:
2036: /* If that makes it a no-op (copying the register into itself)
2037: then delete it so it won't appear to be a "use" and a "set"
2038: of this register. */
2039: if (SET_DEST (PATTERN (incr)) == addr)
2040: {
2041: PUT_CODE (incr, NOTE);
2042: NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
2043: NOTE_SOURCE_FILE (incr) = 0;
2044: }
2045:
2046: if (regno >= FIRST_PSEUDO_REGISTER)
2047: {
2048: /* Count an extra reference to the reg. When a reg is
2049: incremented, spilling it is worse, so we want to make
2050: that less likely. */
2051: reg_n_refs[regno] += loop_depth;
2052: /* Count the increment as a setting of the register,
2053: even though it isn't a SET in rtl. */
2054: reg_n_sets[regno]++;
2055: }
2056: }
2057: }
2058: }
2059: }
2060: #endif /* AUTO_INC_DEC */
2061:
2062: /* Scan expression X and store a 1-bit in LIVE for each reg it uses.
2063: This is done assuming the registers needed from X
2064: are those that have 1-bits in NEEDED.
2065:
2066: On the final pass, FINAL is 1. This means try for autoincrement
2067: and count the uses and deaths of each pseudo-reg.
2068:
2069: INSN is the containing instruction. If INSN is dead, this function is not
2070: called. */
2071:
2072: static void
2073: mark_used_regs (needed, live, x, final, insn)
2074: regset needed;
2075: regset live;
2076: rtx x;
2077: rtx insn;
2078: int final;
2079: {
2080: register RTX_CODE code;
2081: register int regno;
2082: int i;
2083:
2084: retry:
2085: code = GET_CODE (x);
2086: switch (code)
2087: {
2088: case LABEL_REF:
2089: case SYMBOL_REF:
2090: case CONST_INT:
2091: case CONST:
2092: case CONST_DOUBLE:
2093: case PC:
2094: case CLOBBER:
2095: case ADDR_VEC:
2096: case ADDR_DIFF_VEC:
2097: case ASM_INPUT:
2098: return;
2099:
2100: #ifdef HAVE_cc0
2101: case CC0:
2102: cc0_live = 1;
2103: return;
2104: #endif
2105:
2106: case MEM:
2107: /* Invalidate the data for the last MEM stored. We could do this only
2108: if the addresses conflict, but this doesn't seem worthwhile. */
2109: last_mem_set = 0;
2110:
2111: #ifdef AUTO_INC_DEC
2112: if (final)
2113: find_auto_inc (needed, x, insn);
2114: #endif
2115: break;
2116:
2117: case REG:
2118: /* See a register other than being set
2119: => mark it as needed. */
2120:
2121: regno = REGNO (x);
2122: {
2123: register int offset = regno / REGSET_ELT_BITS;
2124: register int bit = 1 << (regno % REGSET_ELT_BITS);
2125: int all_needed = (needed[offset] & bit) != 0;
2126: int some_needed = (needed[offset] & bit) != 0;
2127:
2128: live[offset] |= bit;
2129: /* A hard reg in a wide mode may really be multiple registers.
2130: If so, mark all of them just like the first. */
2131: if (regno < FIRST_PSEUDO_REGISTER)
2132: {
2133: int n;
2134:
2135: /* For stack ptr or fixed arg pointer,
2136: nothing below can be necessary, so waste no more time. */
2137: if (regno == STACK_POINTER_REGNUM
2138: #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2139: || (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
2140: #endif
2141: || regno == FRAME_POINTER_REGNUM)
2142: {
2143: /* If this is a register we are going to try to eliminate,
2144: don't mark it live here. If we are successful in
2145: eliminating it, it need not be live unless it is used for
2146: pseudos, in which case it will have been set live when
2147: it was allocated to the pseudos. If the register will not
2148: be eliminated, reload will set it live at that point. */
2149:
2150: if (! TEST_HARD_REG_BIT (elim_reg_set, regno))
2151: regs_ever_live[regno] = 1;
2152: return;
2153: }
2154: /* No death notes for global register variables;
2155: their values are live after this function exits. */
2156: if (global_regs[regno])
2157: return;
2158:
2159: n = HARD_REGNO_NREGS (regno, GET_MODE (x));
2160: while (--n > 0)
2161: {
2162: live[(regno + n) / REGSET_ELT_BITS]
2163: |= 1 << ((regno + n) % REGSET_ELT_BITS);
2164: some_needed |= (needed[(regno + n) / REGSET_ELT_BITS]
2165: & 1 << ((regno + n) % REGSET_ELT_BITS));
2166: all_needed &= (needed[(regno + n) / REGSET_ELT_BITS]
2167: & 1 << ((regno + n) % REGSET_ELT_BITS));
2168: }
2169: }
2170: if (final)
2171: {
2172: /* Record where each reg is used, so when the reg
2173: is set we know the next insn that uses it. */
2174:
2175: reg_next_use[regno] = insn;
2176:
2177: if (regno < FIRST_PSEUDO_REGISTER)
2178: {
2179: /* If a hard reg is being used,
2180: record that this function does use it. */
2181:
2182: i = HARD_REGNO_NREGS (regno, GET_MODE (x));
2183: if (i == 0)
2184: i = 1;
2185: do
2186: regs_ever_live[regno + --i] = 1;
2187: while (i > 0);
2188: }
2189: else
2190: {
2191: /* Keep track of which basic block each reg appears in. */
2192:
2193: register int blocknum = BLOCK_NUM (insn);
2194:
2195: if (reg_basic_block[regno] == REG_BLOCK_UNKNOWN)
2196: reg_basic_block[regno] = blocknum;
2197: else if (reg_basic_block[regno] != blocknum)
2198: reg_basic_block[regno] = REG_BLOCK_GLOBAL;
2199:
2200: /* Count (weighted) number of uses of each reg. */
2201:
2202: reg_n_refs[regno] += loop_depth;
2203: }
2204:
2205: /* Record and count the insns in which a reg dies.
2206: If it is used in this insn and was dead below the insn
2207: then it dies in this insn. If it was set in this insn,
2208: we do not make a REG_DEAD note; likewise if we already
2209: made such a note. */
2210:
2211: if (! all_needed
2212: && ! dead_or_set_p (insn, x)
2213: #if 0
2214: && (regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno])
2215: #endif
2216: )
2217: {
2218: /* If none of the words in X is needed, make a REG_DEAD
2219: note. Otherwise, we must make partial REG_DEAD notes. */
2220: if (! some_needed)
2221: {
2222: REG_NOTES (insn)
2223: = gen_rtx (EXPR_LIST, REG_DEAD, x, REG_NOTES (insn));
2224: reg_n_deaths[regno]++;
2225: }
2226: else
2227: {
2228: int i;
2229:
2230: /* Don't make a REG_DEAD note for a part of a register
2231: that is set in the insn. */
2232:
2233: for (i = HARD_REGNO_NREGS (regno, GET_MODE (x)) - 1;
2234: i >= 0; i--)
2235: if ((needed[(regno + i) / REGSET_ELT_BITS]
2236: & 1 << ((regno + i) % REGSET_ELT_BITS)) == 0
2237: && ! dead_or_set_regno_p (insn, regno + i))
2238: REG_NOTES (insn)
2239: = gen_rtx (EXPR_LIST, REG_DEAD,
2240: gen_rtx (REG, word_mode, regno + i),
2241: REG_NOTES (insn));
2242: }
2243: }
2244: }
2245: }
2246: return;
2247:
2248: case SET:
2249: {
2250: register rtx testreg = SET_DEST (x);
2251: int mark_dest = 0;
2252:
2253: /* If storing into MEM, don't show it as being used. But do
2254: show the address as being used. */
2255: if (GET_CODE (testreg) == MEM)
2256: {
2257: #ifdef AUTO_INC_DEC
2258: if (final)
2259: find_auto_inc (needed, testreg, insn);
2260: #endif
2261: mark_used_regs (needed, live, XEXP (testreg, 0), final, insn);
2262: mark_used_regs (needed, live, SET_SRC (x), final, insn);
2263: return;
2264: }
2265:
2266: /* Storing in STRICT_LOW_PART is like storing in a reg
2267: in that this SET might be dead, so ignore it in TESTREG.
2268: but in some other ways it is like using the reg.
2269:
2270: Storing in a SUBREG or a bit field is like storing the entire
2271: register in that if the register's value is not used
2272: then this SET is not needed. */
2273: while (GET_CODE (testreg) == STRICT_LOW_PART
2274: || GET_CODE (testreg) == ZERO_EXTRACT
2275: || GET_CODE (testreg) == SIGN_EXTRACT
2276: || GET_CODE (testreg) == SUBREG)
2277: {
2278: /* Modifying a single register in an alternate mode
2279: does not use any of the old value. But these other
2280: ways of storing in a register do use the old value. */
2281: if (GET_CODE (testreg) == SUBREG
2282: && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
2283: ;
2284: else
2285: mark_dest = 1;
2286:
2287: testreg = XEXP (testreg, 0);
2288: }
2289:
2290: /* If this is a store into a register,
2291: recursively scan the value being stored. */
2292:
2293: if (GET_CODE (testreg) == REG
2294: && (regno = REGNO (testreg), regno != FRAME_POINTER_REGNUM)
2295: #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2296: && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
2297: #endif
2298: && ! (regno < FIRST_PSEUDO_REGISTER && global_regs[regno]))
2299: {
2300: mark_used_regs (needed, live, SET_SRC (x), final, insn);
2301: if (mark_dest)
2302: mark_used_regs (needed, live, SET_DEST (x), final, insn);
2303: return;
2304: }
2305: }
2306: break;
2307:
2308: case RETURN:
2309: /* If exiting needs the right stack value, consider this insn as
2310: using the stack pointer. In any event, consider it as using
2311: all global registers. */
2312:
2313: #ifdef EXIT_IGNORE_STACK
2314: if (! EXIT_IGNORE_STACK
2315: || (! FRAME_POINTER_REQUIRED && flag_omit_frame_pointer))
2316: #endif
2317: live[STACK_POINTER_REGNUM / REGSET_ELT_BITS]
2318: |= 1 << (STACK_POINTER_REGNUM % REGSET_ELT_BITS);
2319:
2320: for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
2321: if (global_regs[i])
2322: live[i / REGSET_ELT_BITS] |= 1 << (i % REGSET_ELT_BITS);
2323: break;
2324: }
2325:
2326: /* Recursively scan the operands of this expression. */
2327:
2328: {
2329: register char *fmt = GET_RTX_FORMAT (code);
2330: register int i;
2331:
2332: for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2333: {
2334: if (fmt[i] == 'e')
2335: {
2336: /* Tail recursive case: save a function call level. */
2337: if (i == 0)
2338: {
2339: x = XEXP (x, 0);
2340: goto retry;
2341: }
2342: mark_used_regs (needed, live, XEXP (x, i), final, insn);
2343: }
2344: else if (fmt[i] == 'E')
2345: {
2346: register int j;
2347: for (j = 0; j < XVECLEN (x, i); j++)
2348: mark_used_regs (needed, live, XVECEXP (x, i, j), final, insn);
2349: }
2350: }
2351: }
2352: }
2353:
2354: #ifdef AUTO_INC_DEC
2355:
2356: static int
2357: try_pre_increment_1 (insn)
2358: rtx insn;
2359: {
2360: /* Find the next use of this reg. If in same basic block,
2361: make it do pre-increment or pre-decrement if appropriate. */
2362: rtx x = PATTERN (insn);
2363: int amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
2364: * INTVAL (XEXP (SET_SRC (x), 1)));
2365: int regno = REGNO (SET_DEST (x));
2366: rtx y = reg_next_use[regno];
2367: if (y != 0
2368: && BLOCK_NUM (y) == BLOCK_NUM (insn)
2369: && try_pre_increment (y, SET_DEST (PATTERN (insn)),
2370: amount))
2371: {
2372: /* We have found a suitable auto-increment
2373: and already changed insn Y to do it.
2374: So flush this increment-instruction. */
2375: PUT_CODE (insn, NOTE);
2376: NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
2377: NOTE_SOURCE_FILE (insn) = 0;
2378: /* Count a reference to this reg for the increment
2379: insn we are deleting. When a reg is incremented.
2380: spilling it is worse, so we want to make that
2381: less likely. */
2382: if (regno >= FIRST_PSEUDO_REGISTER)
2383: {
2384: reg_n_refs[regno] += loop_depth;
2385: reg_n_sets[regno]++;
2386: }
2387: return 1;
2388: }
2389: return 0;
2390: }
2391:
2392: /* Try to change INSN so that it does pre-increment or pre-decrement
2393: addressing on register REG in order to add AMOUNT to REG.
2394: AMOUNT is negative for pre-decrement.
2395: Returns 1 if the change could be made.
2396: This checks all about the validity of the result of modifying INSN. */
2397:
2398: static int
2399: try_pre_increment (insn, reg, amount)
2400: rtx insn, reg;
2401: int amount;
2402: {
2403: register rtx use;
2404:
2405: /* Nonzero if we can try to make a pre-increment or pre-decrement.
2406: For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
2407: int pre_ok = 0;
2408: /* Nonzero if we can try to make a post-increment or post-decrement.
2409: For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
2410: It is possible for both PRE_OK and POST_OK to be nonzero if the machine
2411: supports both pre-inc and post-inc, or both pre-dec and post-dec. */
2412: int post_ok = 0;
2413:
2414: /* Nonzero if the opportunity actually requires post-inc or post-dec. */
2415: int do_post = 0;
2416:
2417: /* From the sign of increment, see which possibilities are conceivable
2418: on this target machine. */
2419: #ifdef HAVE_PRE_INCREMENT
2420: if (amount > 0)
2421: pre_ok = 1;
2422: #endif
2423: #ifdef HAVE_POST_INCREMENT
2424: if (amount > 0)
2425: post_ok = 1;
2426: #endif
2427:
2428: #ifdef HAVE_PRE_DECREMENT
2429: if (amount < 0)
2430: pre_ok = 1;
2431: #endif
2432: #ifdef HAVE_POST_DECREMENT
2433: if (amount < 0)
2434: post_ok = 1;
2435: #endif
2436:
2437: if (! (pre_ok || post_ok))
2438: return 0;
2439:
2440: /* It is not safe to add a side effect to a jump insn
2441: because if the incremented register is spilled and must be reloaded
2442: there would be no way to store the incremented value back in memory. */
2443:
2444: if (GET_CODE (insn) == JUMP_INSN)
2445: return 0;
2446:
2447: use = 0;
2448: if (pre_ok)
2449: use = find_use_as_address (PATTERN (insn), reg, 0);
2450: if (post_ok && (use == 0 || use == (rtx) 1))
2451: {
2452: use = find_use_as_address (PATTERN (insn), reg, -amount);
2453: do_post = 1;
2454: }
2455:
2456: if (use == 0 || use == (rtx) 1)
2457: return 0;
2458:
2459: if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
2460: return 0;
2461:
2462: XEXP (use, 0) = gen_rtx (amount > 0
2463: ? (do_post ? POST_INC : PRE_INC)
2464: : (do_post ? POST_DEC : PRE_DEC),
2465: Pmode, reg);
2466:
2467: /* Record that this insn now has an implicit side effect on X. */
2468: REG_NOTES (insn) = gen_rtx (EXPR_LIST, REG_INC, reg, REG_NOTES (insn));
2469: return 1;
2470: }
2471:
2472: #endif /* AUTO_INC_DEC */
2473:
2474: /* Find the place in the rtx X where REG is used as a memory address.
2475: Return the MEM rtx that so uses it.
2476: If PLUSCONST is nonzero, search instead for a memory address equivalent to
2477: (plus REG (const_int PLUSCONST)).
2478:
2479: If such an address does not appear, return 0.
2480: If REG appears more than once, or is used other than in such an address,
2481: return (rtx)1. */
2482:
2483: static rtx
2484: find_use_as_address (x, reg, plusconst)
2485: register rtx x;
2486: rtx reg;
2487: int plusconst;
2488: {
2489: enum rtx_code code = GET_CODE (x);
2490: char *fmt = GET_RTX_FORMAT (code);
2491: register int i;
2492: register rtx value = 0;
2493: register rtx tem;
2494:
2495: if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
2496: return x;
2497:
2498: if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
2499: && XEXP (XEXP (x, 0), 0) == reg
2500: && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
2501: && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
2502: return x;
2503:
2504: if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
2505: {
2506: /* If REG occurs inside a MEM used in a bit-field reference,
2507: that is unacceptable. */
2508: if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
2509: return (rtx) 1;
2510: }
2511:
2512: if (x == reg)
2513: return (rtx) 1;
2514:
2515: for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2516: {
2517: if (fmt[i] == 'e')
2518: {
2519: tem = find_use_as_address (XEXP (x, i), reg, plusconst);
2520: if (value == 0)
2521: value = tem;
2522: else if (tem != 0)
2523: return (rtx) 1;
2524: }
2525: if (fmt[i] == 'E')
2526: {
2527: register int j;
2528: for (j = XVECLEN (x, i) - 1; j >= 0; j--)
2529: {
2530: tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
2531: if (value == 0)
2532: value = tem;
2533: else if (tem != 0)
2534: return (rtx) 1;
2535: }
2536: }
2537: }
2538:
2539: return value;
2540: }
2541:
2542: /* Write information about registers and basic blocks into FILE.
2543: This is part of making a debugging dump. */
2544:
2545: void
2546: dump_flow_info (file)
2547: FILE *file;
2548: {
2549: register int i;
2550: static char *reg_class_names[] = REG_CLASS_NAMES;
2551:
2552: fprintf (file, "%d registers.\n", max_regno);
2553:
2554: for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
2555: if (reg_n_refs[i])
2556: {
2557: enum reg_class class;
2558: fprintf (file, "\nRegister %d used %d times across %d insns",
2559: i, reg_n_refs[i], reg_live_length[i]);
2560: if (reg_basic_block[i] >= 0)
2561: fprintf (file, " in block %d", reg_basic_block[i]);
2562: if (reg_n_deaths[i] != 1)
2563: fprintf (file, "; dies in %d places", reg_n_deaths[i]);
2564: if (reg_n_calls_crossed[i] == 1)
2565: fprintf (file, "; crosses 1 call");
2566: else if (reg_n_calls_crossed[i])
2567: fprintf (file, "; crosses %d calls", reg_n_calls_crossed[i]);
2568: if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
2569: fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
2570: class = reg_preferred_class (i);
2571: if (class != GENERAL_REGS)
2572: {
2573: if (reg_preferred_or_nothing (i))
2574: fprintf (file, "; %s or none", reg_class_names[(int) class]);
2575: else
2576: fprintf (file, "; pref %s", reg_class_names[(int) class]);
2577: }
2578: if (REGNO_POINTER_FLAG (i))
2579: fprintf (file, "; pointer");
2580: fprintf (file, ".\n");
2581: }
2582: fprintf (file, "\n%d basic blocks.\n", n_basic_blocks);
2583: for (i = 0; i < n_basic_blocks; i++)
2584: {
2585: register rtx head, jump;
2586: register int regno;
2587: fprintf (file, "\nBasic block %d: first insn %d, last %d.\n",
2588: i,
2589: INSN_UID (basic_block_head[i]),
2590: INSN_UID (basic_block_end[i]));
2591: /* The control flow graph's storage is freed
2592: now when flow_analysis returns.
2593: Don't try to print it if it is gone. */
2594: if (basic_block_drops_in)
2595: {
2596: fprintf (file, "Reached from blocks: ");
2597: head = basic_block_head[i];
2598: if (GET_CODE (head) == CODE_LABEL)
2599: for (jump = LABEL_REFS (head);
2600: jump != head;
2601: jump = LABEL_NEXTREF (jump))
2602: {
2603: register int from_block = BLOCK_NUM (CONTAINING_INSN (jump));
2604: fprintf (file, " %d", from_block);
2605: }
2606: if (basic_block_drops_in[i])
2607: fprintf (file, " previous");
2608: }
2609: fprintf (file, "\nRegisters live at start:");
2610: for (regno = 0; regno < max_regno; regno++)
2611: {
2612: register int offset = regno / REGSET_ELT_BITS;
2613: register int bit = 1 << (regno % REGSET_ELT_BITS);
2614: if (basic_block_live_at_start[i][offset] & bit)
2615: fprintf (file, " %d", regno);
2616: }
2617: fprintf (file, "\n");
2618: }
2619: fprintf (file, "\n");
2620: }
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