| 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 | } |