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15637ed4 RG |
1 | /* Analyze RTL for C-Compiler |
2 | Copyright (C) 1987, 1988 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 1, 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 | #include "config.h" | |
22 | #include "rtl.h" | |
23 | ||
24 | extern void note_stores (); | |
25 | static int reg_set_p (); | |
26 | \f | |
27 | /* Return 1 if the value of X is unstable | |
28 | (would be different at a different point in the program). | |
29 | The frame pointer, arg pointer, etc. are considered stable | |
30 | (within one function) and so is anything marked `unchanging'. */ | |
31 | ||
32 | int | |
33 | rtx_unstable_p (x) | |
34 | rtx x; | |
35 | { | |
36 | register RTX_CODE code = GET_CODE (x); | |
37 | register int i; | |
38 | register char *fmt; | |
39 | ||
40 | if (code == MEM) | |
41 | return ! RTX_UNCHANGING_P (x); | |
42 | ||
43 | if (code == QUEUED) | |
44 | return 1; | |
45 | ||
46 | if (code == CONST || code == CONST_INT) | |
47 | return 0; | |
48 | ||
49 | if (code == REG) | |
50 | return ! (REGNO (x) == FRAME_POINTER_REGNUM | |
51 | || REGNO (x) == ARG_POINTER_REGNUM | |
52 | || RTX_UNCHANGING_P (x)); | |
53 | ||
54 | fmt = GET_RTX_FORMAT (code); | |
55 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
56 | if (fmt[i] == 'e') | |
57 | if (rtx_unstable_p (XEXP (x, i))) | |
58 | return 1; | |
59 | return 0; | |
60 | } | |
61 | ||
62 | /* Return 1 if X has a value that can vary even between two | |
63 | executions of the program. 0 means X can be compared reliably | |
64 | against certain constants or near-constants. | |
65 | The frame pointer and the arg pointer are considered constant. */ | |
66 | ||
67 | int | |
68 | rtx_varies_p (x) | |
69 | rtx x; | |
70 | { | |
71 | register RTX_CODE code = GET_CODE (x); | |
72 | register int i; | |
73 | register char *fmt; | |
74 | ||
75 | if (code == MEM) | |
76 | return 1; | |
77 | ||
78 | if (code == QUEUED) | |
79 | return 1; | |
80 | ||
81 | if (code == CONST || code == CONST_INT) | |
82 | return 0; | |
83 | ||
84 | if (code == REG) | |
85 | return ! (REGNO (x) == FRAME_POINTER_REGNUM | |
86 | || REGNO (x) == ARG_POINTER_REGNUM); | |
87 | ||
88 | fmt = GET_RTX_FORMAT (code); | |
89 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
90 | if (fmt[i] == 'e') | |
91 | if (rtx_varies_p (XEXP (x, i))) | |
92 | return 1; | |
93 | return 0; | |
94 | } | |
95 | ||
96 | /* Return 1 if X refers to a memory location whose address | |
97 | cannot be compared reliably with constant addresses, | |
98 | or if X refers to a BLKmode memory object. */ | |
99 | ||
100 | int | |
101 | rtx_addr_varies_p (x) | |
102 | rtx x; | |
103 | { | |
104 | register enum rtx_code code; | |
105 | register int i; | |
106 | register char *fmt; | |
107 | ||
108 | if (x == 0) | |
109 | return 0; | |
110 | ||
111 | code = GET_CODE (x); | |
112 | if (code == MEM) | |
113 | return GET_MODE (x) == BLKmode || rtx_varies_p (XEXP (x, 0)); | |
114 | ||
115 | fmt = GET_RTX_FORMAT (code); | |
116 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
117 | if (fmt[i] == 'e') | |
118 | if (rtx_addr_varies_p (XEXP (x, i))) | |
119 | return 1; | |
120 | return 0; | |
121 | } | |
122 | \f | |
123 | /* Nonzero if register REG appears somewhere within IN. | |
124 | Also works if REG is not a register; in this case it checks | |
125 | for a subexpression of IN that is Lisp "equal" to REG. */ | |
126 | ||
127 | int | |
128 | reg_mentioned_p (reg, in) | |
129 | register rtx reg, in; | |
130 | { | |
131 | register char *fmt; | |
132 | register int i; | |
133 | register enum rtx_code code; | |
134 | ||
135 | if (in == 0) | |
136 | return 0; | |
137 | ||
138 | if (reg == in) | |
139 | return 1; | |
140 | ||
141 | code = GET_CODE (in); | |
142 | ||
143 | switch (code) | |
144 | { | |
145 | /* Compare registers by number. */ | |
146 | case REG: | |
147 | return GET_CODE (reg) == REG && REGNO (in) == REGNO (reg); | |
148 | ||
149 | /* These codes have no constituent expressions | |
150 | and are unique. */ | |
151 | case CC0: | |
152 | case PC: | |
153 | return 0; | |
154 | ||
155 | case CONST_INT: | |
156 | return GET_CODE (reg) == CONST_INT && INTVAL (in) == INTVAL (reg); | |
157 | } | |
158 | ||
159 | if (GET_CODE (reg) == code && rtx_equal_p (reg, in)) | |
160 | return 1; | |
161 | ||
162 | fmt = GET_RTX_FORMAT (code); | |
163 | ||
164 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
165 | { | |
166 | if (fmt[i] == 'E') | |
167 | { | |
168 | register int j; | |
169 | for (j = XVECLEN (in, i) - 1; j >= 0; j--) | |
170 | if (reg_mentioned_p (reg, XVECEXP (in, i, j))) | |
171 | return 1; | |
172 | } | |
173 | else if (fmt[i] == 'e' | |
174 | && reg_mentioned_p (reg, XEXP (in, i))) | |
175 | return 1; | |
176 | } | |
177 | return 0; | |
178 | } | |
179 | ||
180 | /* Nonzero if register REG is used in an insn between | |
181 | FROM_INSN and TO_INSN (exclusive of those two). */ | |
182 | ||
183 | int | |
184 | reg_used_between_p (reg, from_insn, to_insn) | |
185 | rtx reg, from_insn, to_insn; | |
186 | { | |
187 | register rtx insn; | |
188 | register RTX_CODE code; | |
189 | for (insn = NEXT_INSN (from_insn); insn != to_insn; insn = NEXT_INSN (insn)) | |
190 | if (((code = GET_CODE (insn)) == INSN | |
191 | || code == JUMP_INSN || code == CALL_INSN) | |
192 | && reg_mentioned_p (reg, PATTERN (insn))) | |
193 | return 1; | |
194 | return 0; | |
195 | } | |
196 | ||
197 | /* Nonzero if register REG is set or clobbered in an insn between | |
198 | FROM_INSN and TO_INSN (exclusive of those two). | |
199 | Does not notice increments, only SET and CLOBBER. */ | |
200 | ||
201 | int | |
202 | reg_set_between_p (reg, from_insn, to_insn) | |
203 | rtx reg, from_insn, to_insn; | |
204 | { | |
205 | register rtx insn; | |
206 | register RTX_CODE code; | |
207 | for (insn = NEXT_INSN (from_insn); insn != to_insn; insn = NEXT_INSN (insn)) | |
208 | if (((code = GET_CODE (insn)) == INSN | |
209 | || code == JUMP_INSN || code == CALL_INSN) | |
210 | && reg_set_p (reg, PATTERN (insn))) | |
211 | return 1; | |
212 | return 0; | |
213 | } | |
214 | ||
215 | /* Internals of reg_set_between_p. */ | |
216 | ||
217 | static rtx reg_set_reg; | |
218 | static int reg_set_flag; | |
219 | ||
220 | static void | |
221 | reg_set_p_1 (x) | |
222 | rtx x; | |
223 | { | |
224 | if (reg_overlap_mentioned_p (reg_set_reg, x)) | |
225 | reg_set_flag = 1; | |
226 | } | |
227 | ||
228 | static int | |
229 | reg_set_p (reg, insn) | |
230 | rtx reg, insn; | |
231 | { | |
232 | reg_set_reg = reg; | |
233 | reg_set_flag = 0; | |
234 | note_stores (insn, reg_set_p_1); | |
235 | return reg_set_flag; | |
236 | } | |
237 | \f | |
238 | /* Return nonzero if hard register in range [REGNO, ENDREGNO) | |
239 | appears either explicitly or implicitly in X | |
240 | other than being stored into. | |
241 | ||
242 | References contained within the substructure at LOC do not count. | |
243 | LOC may be zero, meaning don't ignore anything. */ | |
244 | ||
245 | int | |
246 | refers_to_regno_p (regno, endregno, x, loc) | |
247 | int regno, endregno; | |
248 | rtx x; | |
249 | rtx *loc; | |
250 | { | |
251 | register int i; | |
252 | register RTX_CODE code; | |
253 | register char *fmt; | |
254 | ||
255 | repeat: | |
256 | code = GET_CODE (x); | |
257 | if (code == REG) | |
258 | { | |
259 | i = REGNO (x); | |
260 | return (endregno > i && regno < i + HARD_REGNO_NREGS (i, GET_MODE (x))); | |
261 | } | |
262 | ||
263 | if (code == SET) | |
264 | { | |
265 | /* Note setting a SUBREG counts as referring to the REG it is in! */ | |
266 | if (GET_CODE (SET_DEST (x)) != REG | |
267 | && refers_to_regno_p (regno, endregno, SET_DEST (x), loc)) | |
268 | return 1; | |
269 | if (loc == &SET_SRC (x)) | |
270 | return 0; | |
271 | x = SET_SRC (x); | |
272 | goto repeat; | |
273 | } | |
274 | ||
275 | if (code == CLOBBER) | |
276 | { | |
277 | if (GET_CODE (SET_DEST (x)) != REG | |
278 | && refers_to_regno_p (regno, endregno, SET_DEST (x), loc)) | |
279 | return 1; | |
280 | return 0; | |
281 | } | |
282 | ||
283 | /* X does not match, so try its subexpressions. */ | |
284 | ||
285 | fmt = GET_RTX_FORMAT (code); | |
286 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
287 | { | |
288 | if (fmt[i] == 'e' && loc != &XEXP (x, i)) | |
289 | { | |
290 | if (i == 0) | |
291 | { | |
292 | x = XEXP (x, 0); | |
293 | goto repeat; | |
294 | } | |
295 | else | |
296 | if (refers_to_regno_p (regno, endregno, XEXP (x, i), loc)) | |
297 | return 1; | |
298 | } | |
299 | else if (fmt[i] == 'E') | |
300 | { | |
301 | register int j; | |
302 | for (j = XVECLEN (x, i) - 1; j >=0; j--) | |
303 | if (loc != &XVECEXP (x, i, j) | |
304 | && refers_to_regno_p (regno, endregno, XVECEXP (x, i, j), loc)) | |
305 | return 1; | |
306 | } | |
307 | } | |
308 | return 0; | |
309 | } | |
310 | ||
311 | /* Nonzero if X contains any reg that overlaps hard register REG. */ | |
312 | ||
313 | int | |
314 | reg_overlap_mentioned_p (reg, x) | |
315 | rtx reg, x; | |
316 | { | |
317 | int regno = REGNO (reg); | |
318 | int endregno = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); | |
319 | return refers_to_regno_p (regno, endregno, x, 0); | |
320 | } | |
321 | \f | |
322 | /* This is 1 until after reload pass. */ | |
323 | int rtx_equal_function_value_matters; | |
324 | ||
325 | /* Return 1 if X and Y are identical-looking rtx's. | |
326 | This is the Lisp function EQUAL for rtx arguments. */ | |
327 | ||
328 | int | |
329 | rtx_equal_p (x, y) | |
330 | rtx x, y; | |
331 | { | |
332 | register int i; | |
333 | register int j; | |
334 | register enum rtx_code code; | |
335 | register char *fmt; | |
336 | ||
337 | if (x == y) | |
338 | return 1; | |
339 | if (x == 0 || y == 0) | |
340 | return 0; | |
341 | ||
342 | code = GET_CODE (x); | |
343 | /* Rtx's of different codes cannot be equal. */ | |
344 | if (code != GET_CODE (y)) | |
345 | return 0; | |
346 | ||
347 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
348 | (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
349 | ||
350 | if (GET_MODE (x) != GET_MODE (y)) | |
351 | return 0; | |
352 | ||
353 | /* These three types of rtx's can be compared nonrecursively. */ | |
354 | /* Until the end of reload, | |
355 | don't consider the a reference to the return register of the current | |
356 | function the same as the return from a called function. This eases | |
357 | the job of function integration. Once the distinction no longer | |
358 | matters, the insn will be deleted. */ | |
359 | if (code == REG) | |
360 | return (REGNO (x) == REGNO (y) | |
361 | && (! rtx_equal_function_value_matters | |
362 | || REG_FUNCTION_VALUE_P (x) == REG_FUNCTION_VALUE_P (y))); | |
363 | if (code == LABEL_REF) | |
364 | return XEXP (x, 0) == XEXP (y, 0); | |
365 | if (code == SYMBOL_REF) | |
366 | return XSTR (x, 0) == XSTR (y, 0); | |
367 | ||
368 | /* Compare the elements. If any pair of corresponding elements | |
369 | fail to match, return 0 for the whole things. */ | |
370 | ||
371 | fmt = GET_RTX_FORMAT (code); | |
372 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
373 | { | |
374 | switch (fmt[i]) | |
375 | { | |
376 | case 'i': | |
377 | if (XINT (x, i) != XINT (y, i)) | |
378 | return 0; | |
379 | break; | |
380 | ||
381 | case 'E': | |
382 | /* Two vectors must have the same length. */ | |
383 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
384 | return 0; | |
385 | ||
386 | /* And the corresponding elements must match. */ | |
387 | for (j = 0; j < XVECLEN (x, i); j++) | |
388 | if (rtx_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)) == 0) | |
389 | return 0; | |
390 | break; | |
391 | ||
392 | case 'e': | |
393 | if (rtx_equal_p (XEXP (x, i), XEXP (y, i)) == 0) | |
394 | return 0; | |
395 | break; | |
396 | ||
397 | case 's': | |
398 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
399 | return 0; | |
400 | break; | |
401 | ||
402 | case 'u': | |
403 | /* These are just backpointers, so they don't matter. */ | |
404 | break; | |
405 | ||
406 | case '0': | |
407 | break; | |
408 | ||
409 | /* It is believed that rtx's at this level will never | |
410 | contain anything but integers and other rtx's, | |
411 | except for within LABEL_REFs and SYMBOL_REFs. */ | |
412 | default: | |
413 | abort (); | |
414 | } | |
415 | } | |
416 | return 1; | |
417 | } | |
418 | \f | |
419 | /* Call FUN on each register or MEM that is stored into or clobbered by X. | |
420 | (X would be the pattern of an insn). | |
421 | FUN receives two arguments: | |
422 | the REG, MEM, CC0 or PC being stored in or clobbered, | |
423 | the SET or CLOBBER rtx that does the store. */ | |
424 | ||
425 | void | |
426 | note_stores (x, fun) | |
427 | register rtx x; | |
428 | void (*fun) (); | |
429 | { | |
430 | if ((GET_CODE (x) == SET || GET_CODE (x) == CLOBBER)) | |
431 | { | |
432 | register rtx dest = SET_DEST (x); | |
433 | while (GET_CODE (dest) == SUBREG | |
434 | || GET_CODE (dest) == ZERO_EXTRACT | |
435 | || GET_CODE (dest) == SIGN_EXTRACT | |
436 | || GET_CODE (dest) == STRICT_LOW_PART) | |
437 | dest = XEXP (dest, 0); | |
438 | (*fun) (dest, x); | |
439 | } | |
440 | else if (GET_CODE (x) == PARALLEL) | |
441 | { | |
442 | register int i; | |
443 | for (i = XVECLEN (x, 0) - 1; i >= 0; i--) | |
444 | { | |
445 | register rtx y = XVECEXP (x, 0, i); | |
446 | if (GET_CODE (y) == SET || GET_CODE (y) == CLOBBER) | |
447 | { | |
448 | register rtx dest = SET_DEST (y); | |
449 | while (GET_CODE (dest) == SUBREG | |
450 | || GET_CODE (dest) == ZERO_EXTRACT | |
451 | || GET_CODE (dest) == SIGN_EXTRACT | |
452 | || GET_CODE (dest) == STRICT_LOW_PART) | |
453 | dest = XEXP (dest, 0); | |
454 | (*fun) (dest, XVECEXP (x, 0, i)); | |
455 | } | |
456 | } | |
457 | } | |
458 | } | |
459 | \f | |
460 | /* Return nonzero if register REG's old contents don't survive after INSN. | |
461 | This can be because REG dies in INSN or because INSN entirely sets REG. | |
462 | ||
463 | "Entirely set" means set directly and not through a SUBREG, | |
464 | ZERO_EXTRACT or SIGN_EXTRACT, so no trace of the old contents remains. | |
465 | ||
466 | REG may be a hard or pseudo reg. Renumbering is not taken into account, | |
467 | but for this use that makes no difference, since regs don't overlap | |
468 | during their lifetimes. Therefore, this function may be used | |
469 | at any time after deaths have been computed (in flow.c). */ | |
470 | ||
471 | int | |
472 | dead_or_set_p (insn, reg) | |
473 | rtx insn; | |
474 | rtx reg; | |
475 | { | |
476 | register rtx link; | |
477 | register int regno = REGNO (reg); | |
478 | ||
479 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) | |
480 | if ((REG_NOTE_KIND (link) == REG_DEAD | |
481 | || REG_NOTE_KIND (link) == REG_INC) | |
482 | && REGNO (XEXP (link, 0)) == regno) | |
483 | return 1; | |
484 | ||
485 | if (GET_CODE (PATTERN (insn)) == SET) | |
486 | return (GET_CODE (SET_DEST (PATTERN (insn))) == REG | |
487 | && REGNO (SET_DEST (PATTERN (insn))) == regno); | |
488 | else if (GET_CODE (PATTERN (insn)) == PARALLEL) | |
489 | { | |
490 | register int i; | |
491 | for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--) | |
492 | { | |
493 | if (GET_CODE (XVECEXP (PATTERN (insn), 0, i)) == SET | |
494 | && GET_CODE (SET_DEST (XVECEXP (PATTERN (insn), 0, i))) == REG | |
495 | && REGNO (SET_DEST (XVECEXP (PATTERN (insn), 0, i))) == regno) | |
496 | return 1; | |
497 | } | |
498 | } | |
499 | return 0; | |
500 | } | |
501 | ||
502 | /* Return the reg-note of kind KIND in insn INSN, if there is one. | |
503 | If DATUM is nonzero, look for one whose datum is DATUM. */ | |
504 | ||
505 | rtx | |
506 | find_reg_note (insn, kind, datum) | |
507 | rtx insn; | |
508 | enum reg_note kind; | |
509 | rtx datum; | |
510 | { | |
511 | register rtx link; | |
512 | ||
513 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) | |
514 | if (REG_NOTE_KIND (link) == kind | |
515 | && (datum == 0 || datum == XEXP (link, 0))) | |
516 | return link; | |
517 | return 0; | |
518 | } | |
519 | ||
520 | /* Return the reg-note of kind KIND in insn INSN which applies to register | |
521 | number REGNO, if any. Return 0 if there is no such reg-note. */ | |
522 | ||
523 | rtx | |
524 | find_regno_note (insn, kind, regno) | |
525 | rtx insn; | |
526 | enum reg_note kind; | |
527 | int regno; | |
528 | { | |
529 | register rtx link; | |
530 | ||
531 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) | |
532 | if (REG_NOTE_KIND (link) == kind | |
533 | && REGNO (XEXP (link, 0)) == regno) | |
534 | return link; | |
535 | return 0; | |
536 | } | |
537 | \f | |
538 | /* Nonzero if FROM precedes TO with no intervening labels. */ | |
539 | ||
540 | int | |
541 | no_labels_between (from, to) | |
542 | register rtx from, to; | |
543 | { | |
544 | register rtx p = to; | |
545 | ||
546 | while (1) | |
547 | { | |
548 | p = PREV_INSN (p); | |
549 | if (p == 0) | |
550 | return 0; | |
551 | if (p == from) | |
552 | return 1; | |
553 | if (GET_CODE (p) == CODE_LABEL) | |
554 | return 0; | |
555 | } | |
556 | } | |
557 | \f | |
558 | /* Nonzero if X contains any volatile memory references | |
559 | or volatile ASM_OPERANDS expressions. */ | |
560 | ||
561 | int | |
562 | volatile_refs_p (x) | |
563 | rtx x; | |
564 | { | |
565 | register RTX_CODE code; | |
566 | ||
567 | code = GET_CODE (x); | |
568 | switch (code) | |
569 | { | |
570 | case LABEL_REF: | |
571 | case SYMBOL_REF: | |
572 | case CONST_INT: | |
573 | case CONST: | |
574 | case CONST_DOUBLE: | |
575 | case CC0: | |
576 | case PC: | |
577 | case REG: | |
578 | case CLOBBER: | |
579 | case ASM_INPUT: | |
580 | case ADDR_VEC: | |
581 | case ADDR_DIFF_VEC: | |
582 | return 0; | |
583 | ||
584 | case CALL: | |
585 | return 1; | |
586 | ||
587 | case MEM: | |
588 | case ASM_OPERANDS: | |
589 | if (MEM_VOLATILE_P (x)) | |
590 | return 1; | |
591 | } | |
592 | ||
593 | /* Recursively scan the operands of this expression. */ | |
594 | ||
595 | { | |
596 | register char *fmt = GET_RTX_FORMAT (code); | |
597 | register int i; | |
598 | ||
599 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
600 | { | |
601 | if (fmt[i] == 'e') | |
602 | { | |
603 | if (volatile_refs_p (XEXP (x, i))) | |
604 | return 1; | |
605 | } | |
606 | if (fmt[i] == 'E') | |
607 | { | |
608 | register int j; | |
609 | for (j = 0; j < XVECLEN (x, i); j++) | |
610 | if (volatile_refs_p (XVECEXP (x, i, j))) | |
611 | return 1; | |
612 | } | |
613 | } | |
614 | } | |
615 | return 0; | |
616 | } | |
617 | \f | |
618 | /* Return nonzero if evaluating rtx X might cause a trap. */ | |
619 | ||
620 | int | |
621 | may_trap_p (x) | |
622 | rtx x; | |
623 | { | |
624 | int i; | |
625 | enum rtx_code code; | |
626 | char *fmt; | |
627 | ||
628 | if (x == 0) | |
629 | return 0; | |
630 | code = GET_CODE (x); | |
631 | switch (code) | |
632 | { | |
633 | /* Handle these cases fast. */ | |
634 | case CONST_INT: | |
635 | case CONST_DOUBLE: | |
636 | case SYMBOL_REF: | |
637 | case LABEL_REF: | |
638 | case CONST: | |
639 | case PC: | |
640 | case CC0: | |
641 | case REG: | |
642 | return 0; | |
643 | ||
644 | /* Memory ref can trap unless it's a static var or a stack slot. */ | |
645 | case MEM: | |
646 | return rtx_varies_p (XEXP (x, 0)); | |
647 | ||
648 | /* Division by a non-constant might trap. */ | |
649 | case DIV: | |
650 | case MOD: | |
651 | case UDIV: | |
652 | case UMOD: | |
653 | if (! CONSTANT_P (XEXP (x, 1)) | |
654 | && GET_CODE (XEXP (x, 1)) != CONST_DOUBLE) | |
655 | return 1; | |
656 | if (XEXP (x, 1) == const0_rtx) | |
657 | return 1; | |
658 | default: | |
659 | /* Any floating arithmetic may trap. */ | |
660 | if (GET_MODE_CLASS (GET_MODE (x)) == MODE_FLOAT) | |
661 | return 1; | |
662 | } | |
663 | ||
664 | fmt = GET_RTX_FORMAT (code); | |
665 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
666 | { | |
667 | if (fmt[i] == 'e') | |
668 | { | |
669 | if (may_trap_p (XEXP (x, i))) | |
670 | return 1; | |
671 | } | |
672 | else if (fmt[i] == 'E') | |
673 | { | |
674 | register int j; | |
675 | for (j = 0; j < XVECLEN (x, i); j++) | |
676 | if (may_trap_p (XVECEXP (x, i, j))) | |
677 | return 1; | |
678 | } | |
679 | } | |
680 | return 0; | |
681 | } |