1 /* Optimize jump instructions, for GNU compiler. 2 Copyright (C) 1987, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997 3 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009 4 Free Software Foundation, Inc. 5 6 This file is part of GCC. 7 8 GCC is free software; you can redistribute it and/or modify it under 9 the terms of the GNU General Public License as published by the Free 10 Software Foundation; either version 3, or (at your option) any later 11 version. 12 13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 14 WARRANTY; without even the implied warranty of MERCHANTABILITY or 15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 16 for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with GCC; see the file COPYING3. If not see 20 <http://www.gnu.org/licenses/>. */ 21 22 /* This is the pathetic reminder of old fame of the jump-optimization pass 23 of the compiler. Now it contains basically a set of utility functions to 24 operate with jumps. 25 26 Each CODE_LABEL has a count of the times it is used 27 stored in the LABEL_NUSES internal field, and each JUMP_INSN 28 has one label that it refers to stored in the 29 JUMP_LABEL internal field. With this we can detect labels that 30 become unused because of the deletion of all the jumps that 31 formerly used them. The JUMP_LABEL info is sometimes looked 32 at by later passes. 33 34 The subroutines redirect_jump and invert_jump are used 35 from other passes as well. */ 36 37 #include "config.h" 38 #include "system.h" 39 #include "coretypes.h" 40 #include "tm.h" 41 #include "rtl.h" 42 #include "tm_p.h" 43 #include "flags.h" 44 #include "hard-reg-set.h" 45 #include "regs.h" 46 #include "insn-config.h" 47 #include "insn-attr.h" 48 #include "recog.h" 49 #include "function.h" 50 #include "expr.h" 51 #include "real.h" 52 #include "except.h" 53 #include "diagnostic.h" 54 #include "toplev.h" 55 #include "reload.h" 56 #include "predict.h" 57 #include "timevar.h" 58 #include "tree-pass.h" 59 #include "target.h" 60 61 /* Optimize jump y; x: ... y: jumpif... x? 62 Don't know if it is worth bothering with. */ 63 /* Optimize two cases of conditional jump to conditional jump? 64 This can never delete any instruction or make anything dead, 65 or even change what is live at any point. 66 So perhaps let combiner do it. */ 67 68 static void init_label_info (rtx); 69 static void mark_all_labels (rtx); 70 static void mark_jump_label_1 (rtx, rtx, bool, bool); 71 static void mark_jump_label_asm (rtx, rtx); 72 static void redirect_exp_1 (rtx *, rtx, rtx, rtx); 73 static int invert_exp_1 (rtx, rtx); 74 static int returnjump_p_1 (rtx *, void *); 75 76 /* This function rebuilds the JUMP_LABEL field and REG_LABEL_TARGET 77 notes in jumping insns and REG_LABEL_OPERAND notes in non-jumping 78 instructions and jumping insns that have labels as operands 79 (e.g. cbranchsi4). */ 80 void 81 rebuild_jump_labels (rtx f) 82 { 83 rtx insn; 84 85 timevar_push (TV_REBUILD_JUMP); 86 init_label_info (f); 87 mark_all_labels (f); 88 89 /* Keep track of labels used from static data; we don't track them 90 closely enough to delete them here, so make sure their reference 91 count doesn't drop to zero. */ 92 93 for (insn = forced_labels; insn; insn = XEXP (insn, 1)) 94 if (LABEL_P (XEXP (insn, 0))) 95 LABEL_NUSES (XEXP (insn, 0))++; 96 timevar_pop (TV_REBUILD_JUMP); 97 } 98 99 /* Some old code expects exactly one BARRIER as the NEXT_INSN of a 100 non-fallthru insn. This is not generally true, as multiple barriers 101 may have crept in, or the BARRIER may be separated from the last 102 real insn by one or more NOTEs. 103 104 This simple pass moves barriers and removes duplicates so that the 105 old code is happy. 106 */ 107 unsigned int 108 cleanup_barriers (void) 109 { 110 rtx insn, next, prev; 111 for (insn = get_insns (); insn; insn = next) 112 { 113 next = NEXT_INSN (insn); 114 if (BARRIER_P (insn)) 115 { 116 prev = prev_nonnote_insn (insn); 117 if (!prev) 118 continue; 119 if (BARRIER_P (prev)) 120 delete_insn (insn); 121 else if (prev != PREV_INSN (insn)) 122 reorder_insns (insn, insn, prev); 123 } 124 } 125 return 0; 126 } 127 128 struct rtl_opt_pass pass_cleanup_barriers = 129 { 130 { 131 RTL_PASS, 132 "barriers", /* name */ 133 NULL, /* gate */ 134 cleanup_barriers, /* execute */ 135 NULL, /* sub */ 136 NULL, /* next */ 137 0, /* static_pass_number */ 138 TV_NONE, /* tv_id */ 139 0, /* properties_required */ 140 0, /* properties_provided */ 141 0, /* properties_destroyed */ 142 0, /* todo_flags_start */ 143 TODO_dump_func /* todo_flags_finish */ 144 } 145 }; 146 147 148 /* Initialize LABEL_NUSES and JUMP_LABEL fields, add REG_LABEL_TARGET 149 for remaining targets for JUMP_P. Delete any REG_LABEL_OPERAND 150 notes whose labels don't occur in the insn any more. */ 151 152 static void 153 init_label_info (rtx f) 154 { 155 rtx insn; 156 157 for (insn = f; insn; insn = NEXT_INSN (insn)) 158 { 159 if (LABEL_P (insn)) 160 LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0); 161 162 /* REG_LABEL_TARGET notes (including the JUMP_LABEL field) are 163 sticky and not reset here; that way we won't lose association 164 with a label when e.g. the source for a target register 165 disappears out of reach for targets that may use jump-target 166 registers. Jump transformations are supposed to transform 167 any REG_LABEL_TARGET notes. The target label reference in a 168 branch may disappear from the branch (and from the 169 instruction before it) for other reasons, like register 170 allocation. */ 171 172 if (INSN_P (insn)) 173 { 174 rtx note, next; 175 176 for (note = REG_NOTES (insn); note; note = next) 177 { 178 next = XEXP (note, 1); 179 if (REG_NOTE_KIND (note) == REG_LABEL_OPERAND 180 && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn))) 181 remove_note (insn, note); 182 } 183 } 184 } 185 } 186 187 /* Mark the label each jump jumps to. 188 Combine consecutive labels, and count uses of labels. */ 189 190 static void 191 mark_all_labels (rtx f) 192 { 193 rtx insn; 194 rtx prev_nonjump_insn = NULL; 195 196 for (insn = f; insn; insn = NEXT_INSN (insn)) 197 if (NONDEBUG_INSN_P (insn)) 198 { 199 mark_jump_label (PATTERN (insn), insn, 0); 200 201 /* If the previous non-jump insn sets something to a label, 202 something that this jump insn uses, make that label the primary 203 target of this insn if we don't yet have any. That previous 204 insn must be a single_set and not refer to more than one label. 205 The jump insn must not refer to other labels as jump targets 206 and must be a plain (set (pc) ...), maybe in a parallel, and 207 may refer to the item being set only directly or as one of the 208 arms in an IF_THEN_ELSE. */ 209 if (! INSN_DELETED_P (insn) 210 && JUMP_P (insn) 211 && JUMP_LABEL (insn) == NULL) 212 { 213 rtx label_note = NULL; 214 rtx pc = pc_set (insn); 215 rtx pc_src = pc != NULL ? SET_SRC (pc) : NULL; 216 217 if (prev_nonjump_insn != NULL) 218 label_note 219 = find_reg_note (prev_nonjump_insn, REG_LABEL_OPERAND, NULL); 220 221 if (label_note != NULL && pc_src != NULL) 222 { 223 rtx label_set = single_set (prev_nonjump_insn); 224 rtx label_dest 225 = label_set != NULL ? SET_DEST (label_set) : NULL; 226 227 if (label_set != NULL 228 /* The source must be the direct LABEL_REF, not a 229 PLUS, UNSPEC, IF_THEN_ELSE etc. */ 230 && GET_CODE (SET_SRC (label_set)) == LABEL_REF 231 && (rtx_equal_p (label_dest, pc_src) 232 || (GET_CODE (pc_src) == IF_THEN_ELSE 233 && (rtx_equal_p (label_dest, XEXP (pc_src, 1)) 234 || rtx_equal_p (label_dest, 235 XEXP (pc_src, 2)))))) 236 237 { 238 /* The CODE_LABEL referred to in the note must be the 239 CODE_LABEL in the LABEL_REF of the "set". We can 240 conveniently use it for the marker function, which 241 requires a LABEL_REF wrapping. */ 242 gcc_assert (XEXP (label_note, 0) 243 == XEXP (SET_SRC (label_set), 0)); 244 245 mark_jump_label_1 (label_set, insn, false, true); 246 gcc_assert (JUMP_LABEL (insn) 247 == XEXP (SET_SRC (label_set), 0)); 248 } 249 } 250 } 251 else if (! INSN_DELETED_P (insn)) 252 prev_nonjump_insn = insn; 253 } 254 else if (LABEL_P (insn)) 255 prev_nonjump_insn = NULL; 256 257 /* If we are in cfglayout mode, there may be non-insns between the 258 basic blocks. If those non-insns represent tablejump data, they 259 contain label references that we must record. */ 260 if (current_ir_type () == IR_RTL_CFGLAYOUT) 261 { 262 basic_block bb; 263 rtx insn; 264 FOR_EACH_BB (bb) 265 { 266 for (insn = bb->il.rtl->header; insn; insn = NEXT_INSN (insn)) 267 if (INSN_P (insn)) 268 { 269 gcc_assert (JUMP_TABLE_DATA_P (insn)); 270 mark_jump_label (PATTERN (insn), insn, 0); 271 } 272 273 for (insn = bb->il.rtl->footer; insn; insn = NEXT_INSN (insn)) 274 if (INSN_P (insn)) 275 { 276 gcc_assert (JUMP_TABLE_DATA_P (insn)); 277 mark_jump_label (PATTERN (insn), insn, 0); 278 } 279 } 280 } 281 } 282 283 /* Given a comparison (CODE ARG0 ARG1), inside an insn, INSN, return a code 284 of reversed comparison if it is possible to do so. Otherwise return UNKNOWN. 285 UNKNOWN may be returned in case we are having CC_MODE compare and we don't 286 know whether it's source is floating point or integer comparison. Machine 287 description should define REVERSIBLE_CC_MODE and REVERSE_CONDITION macros 288 to help this function avoid overhead in these cases. */ 289 enum rtx_code 290 reversed_comparison_code_parts (enum rtx_code code, const_rtx arg0, 291 const_rtx arg1, const_rtx insn) 292 { 293 enum machine_mode mode; 294 295 /* If this is not actually a comparison, we can't reverse it. */ 296 if (GET_RTX_CLASS (code) != RTX_COMPARE 297 && GET_RTX_CLASS (code) != RTX_COMM_COMPARE) 298 return UNKNOWN; 299 300 mode = GET_MODE (arg0); 301 if (mode == VOIDmode) 302 mode = GET_MODE (arg1); 303 304 /* First see if machine description supplies us way to reverse the 305 comparison. Give it priority over everything else to allow 306 machine description to do tricks. */ 307 if (GET_MODE_CLASS (mode) == MODE_CC 308 && REVERSIBLE_CC_MODE (mode)) 309 { 310 #ifdef REVERSE_CONDITION 311 return REVERSE_CONDITION (code, mode); 312 #endif 313 return reverse_condition (code); 314 } 315 316 /* Try a few special cases based on the comparison code. */ 317 switch (code) 318 { 319 case GEU: 320 case GTU: 321 case LEU: 322 case LTU: 323 case NE: 324 case EQ: 325 /* It is always safe to reverse EQ and NE, even for the floating 326 point. Similarly the unsigned comparisons are never used for 327 floating point so we can reverse them in the default way. */ 328 return reverse_condition (code); 329 case ORDERED: 330 case UNORDERED: 331 case LTGT: 332 case UNEQ: 333 /* In case we already see unordered comparison, we can be sure to 334 be dealing with floating point so we don't need any more tests. */ 335 return reverse_condition_maybe_unordered (code); 336 case UNLT: 337 case UNLE: 338 case UNGT: 339 case UNGE: 340 /* We don't have safe way to reverse these yet. */ 341 return UNKNOWN; 342 default: 343 break; 344 } 345 346 if (GET_MODE_CLASS (mode) == MODE_CC || CC0_P (arg0)) 347 { 348 const_rtx prev; 349 /* Try to search for the comparison to determine the real mode. 350 This code is expensive, but with sane machine description it 351 will be never used, since REVERSIBLE_CC_MODE will return true 352 in all cases. */ 353 if (! insn) 354 return UNKNOWN; 355 356 /* These CONST_CAST's are okay because prev_nonnote_insn just 357 returns its argument and we assign it to a const_rtx 358 variable. */ 359 for (prev = prev_nonnote_insn (CONST_CAST_RTX(insn)); 360 prev != 0 && !LABEL_P (prev); 361 prev = prev_nonnote_insn (CONST_CAST_RTX(prev))) 362 { 363 const_rtx set = set_of (arg0, prev); 364 if (set && GET_CODE (set) == SET 365 && rtx_equal_p (SET_DEST (set), arg0)) 366 { 367 rtx src = SET_SRC (set); 368 369 if (GET_CODE (src) == COMPARE) 370 { 371 rtx comparison = src; 372 arg0 = XEXP (src, 0); 373 mode = GET_MODE (arg0); 374 if (mode == VOIDmode) 375 mode = GET_MODE (XEXP (comparison, 1)); 376 break; 377 } 378 /* We can get past reg-reg moves. This may be useful for model 379 of i387 comparisons that first move flag registers around. */ 380 if (REG_P (src)) 381 { 382 arg0 = src; 383 continue; 384 } 385 } 386 /* If register is clobbered in some ununderstandable way, 387 give up. */ 388 if (set) 389 return UNKNOWN; 390 } 391 } 392 393 /* Test for an integer condition, or a floating-point comparison 394 in which NaNs can be ignored. */ 395 if (CONST_INT_P (arg0) 396 || (GET_MODE (arg0) != VOIDmode 397 && GET_MODE_CLASS (mode) != MODE_CC 398 && !HONOR_NANS (mode))) 399 return reverse_condition (code); 400 401 return UNKNOWN; 402 } 403 404 /* A wrapper around the previous function to take COMPARISON as rtx 405 expression. This simplifies many callers. */ 406 enum rtx_code 407 reversed_comparison_code (const_rtx comparison, const_rtx insn) 408 { 409 if (!COMPARISON_P (comparison)) 410 return UNKNOWN; 411 return reversed_comparison_code_parts (GET_CODE (comparison), 412 XEXP (comparison, 0), 413 XEXP (comparison, 1), insn); 414 } 415 416 /* Return comparison with reversed code of EXP. 417 Return NULL_RTX in case we fail to do the reversal. */ 418 rtx 419 reversed_comparison (const_rtx exp, enum machine_mode mode) 420 { 421 enum rtx_code reversed_code = reversed_comparison_code (exp, NULL_RTX); 422 if (reversed_code == UNKNOWN) 423 return NULL_RTX; 424 else 425 return simplify_gen_relational (reversed_code, mode, VOIDmode, 426 XEXP (exp, 0), XEXP (exp, 1)); 427 } 428 429 430 /* Given an rtx-code for a comparison, return the code for the negated 431 comparison. If no such code exists, return UNKNOWN. 432 433 WATCH OUT! reverse_condition is not safe to use on a jump that might 434 be acting on the results of an IEEE floating point comparison, because 435 of the special treatment of non-signaling nans in comparisons. 436 Use reversed_comparison_code instead. */ 437 438 enum rtx_code 439 reverse_condition (enum rtx_code code) 440 { 441 switch (code) 442 { 443 case EQ: 444 return NE; 445 case NE: 446 return EQ; 447 case GT: 448 return LE; 449 case GE: 450 return LT; 451 case LT: 452 return GE; 453 case LE: 454 return GT; 455 case GTU: 456 return LEU; 457 case GEU: 458 return LTU; 459 case LTU: 460 return GEU; 461 case LEU: 462 return GTU; 463 case UNORDERED: 464 return ORDERED; 465 case ORDERED: 466 return UNORDERED; 467 468 case UNLT: 469 case UNLE: 470 case UNGT: 471 case UNGE: 472 case UNEQ: 473 case LTGT: 474 return UNKNOWN; 475 476 default: 477 gcc_unreachable (); 478 } 479 } 480 481 /* Similar, but we're allowed to generate unordered comparisons, which 482 makes it safe for IEEE floating-point. Of course, we have to recognize 483 that the target will support them too... */ 484 485 enum rtx_code 486 reverse_condition_maybe_unordered (enum rtx_code code) 487 { 488 switch (code) 489 { 490 case EQ: 491 return NE; 492 case NE: 493 return EQ; 494 case GT: 495 return UNLE; 496 case GE: 497 return UNLT; 498 case LT: 499 return UNGE; 500 case LE: 501 return UNGT; 502 case LTGT: 503 return UNEQ; 504 case UNORDERED: 505 return ORDERED; 506 case ORDERED: 507 return UNORDERED; 508 case UNLT: 509 return GE; 510 case UNLE: 511 return GT; 512 case UNGT: 513 return LE; 514 case UNGE: 515 return LT; 516 case UNEQ: 517 return LTGT; 518 519 default: 520 gcc_unreachable (); 521 } 522 } 523 524 /* Similar, but return the code when two operands of a comparison are swapped. 525 This IS safe for IEEE floating-point. */ 526 527 enum rtx_code 528 swap_condition (enum rtx_code code) 529 { 530 switch (code) 531 { 532 case EQ: 533 case NE: 534 case UNORDERED: 535 case ORDERED: 536 case UNEQ: 537 case LTGT: 538 return code; 539 540 case GT: 541 return LT; 542 case GE: 543 return LE; 544 case LT: 545 return GT; 546 case LE: 547 return GE; 548 case GTU: 549 return LTU; 550 case GEU: 551 return LEU; 552 case LTU: 553 return GTU; 554 case LEU: 555 return GEU; 556 case UNLT: 557 return UNGT; 558 case UNLE: 559 return UNGE; 560 case UNGT: 561 return UNLT; 562 case UNGE: 563 return UNLE; 564 565 default: 566 gcc_unreachable (); 567 } 568 } 569 570 /* Given a comparison CODE, return the corresponding unsigned comparison. 571 If CODE is an equality comparison or already an unsigned comparison, 572 CODE is returned. */ 573 574 enum rtx_code 575 unsigned_condition (enum rtx_code code) 576 { 577 switch (code) 578 { 579 case EQ: 580 case NE: 581 case GTU: 582 case GEU: 583 case LTU: 584 case LEU: 585 return code; 586 587 case GT: 588 return GTU; 589 case GE: 590 return GEU; 591 case LT: 592 return LTU; 593 case LE: 594 return LEU; 595 596 default: 597 gcc_unreachable (); 598 } 599 } 600 601 /* Similarly, return the signed version of a comparison. */ 602 603 enum rtx_code 604 signed_condition (enum rtx_code code) 605 { 606 switch (code) 607 { 608 case EQ: 609 case NE: 610 case GT: 611 case GE: 612 case LT: 613 case LE: 614 return code; 615 616 case GTU: 617 return GT; 618 case GEU: 619 return GE; 620 case LTU: 621 return LT; 622 case LEU: 623 return LE; 624 625 default: 626 gcc_unreachable (); 627 } 628 } 629 630 /* Return nonzero if CODE1 is more strict than CODE2, i.e., if the 631 truth of CODE1 implies the truth of CODE2. */ 632 633 int 634 comparison_dominates_p (enum rtx_code code1, enum rtx_code code2) 635 { 636 /* UNKNOWN comparison codes can happen as a result of trying to revert 637 comparison codes. 638 They can't match anything, so we have to reject them here. */ 639 if (code1 == UNKNOWN || code2 == UNKNOWN) 640 return 0; 641 642 if (code1 == code2) 643 return 1; 644 645 switch (code1) 646 { 647 case UNEQ: 648 if (code2 == UNLE || code2 == UNGE) 649 return 1; 650 break; 651 652 case EQ: 653 if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU 654 || code2 == ORDERED) 655 return 1; 656 break; 657 658 case UNLT: 659 if (code2 == UNLE || code2 == NE) 660 return 1; 661 break; 662 663 case LT: 664 if (code2 == LE || code2 == NE || code2 == ORDERED || code2 == LTGT) 665 return 1; 666 break; 667 668 case UNGT: 669 if (code2 == UNGE || code2 == NE) 670 return 1; 671 break; 672 673 case GT: 674 if (code2 == GE || code2 == NE || code2 == ORDERED || code2 == LTGT) 675 return 1; 676 break; 677 678 case GE: 679 case LE: 680 if (code2 == ORDERED) 681 return 1; 682 break; 683 684 case LTGT: 685 if (code2 == NE || code2 == ORDERED) 686 return 1; 687 break; 688 689 case LTU: 690 if (code2 == LEU || code2 == NE) 691 return 1; 692 break; 693 694 case GTU: 695 if (code2 == GEU || code2 == NE) 696 return 1; 697 break; 698 699 case UNORDERED: 700 if (code2 == NE || code2 == UNEQ || code2 == UNLE || code2 == UNLT 701 || code2 == UNGE || code2 == UNGT) 702 return 1; 703 break; 704 705 default: 706 break; 707 } 708 709 return 0; 710 } 711 712 /* Return 1 if INSN is an unconditional jump and nothing else. */ 713 714 int 715 simplejump_p (const_rtx insn) 716 { 717 return (JUMP_P (insn) 718 && GET_CODE (PATTERN (insn)) == SET 719 && GET_CODE (SET_DEST (PATTERN (insn))) == PC 720 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF); 721 } 722 723 /* Return nonzero if INSN is a (possibly) conditional jump 724 and nothing more. 725 726 Use of this function is deprecated, since we need to support combined 727 branch and compare insns. Use any_condjump_p instead whenever possible. */ 728 729 int 730 condjump_p (const_rtx insn) 731 { 732 const_rtx x = PATTERN (insn); 733 734 if (GET_CODE (x) != SET 735 || GET_CODE (SET_DEST (x)) != PC) 736 return 0; 737 738 x = SET_SRC (x); 739 if (GET_CODE (x) == LABEL_REF) 740 return 1; 741 else 742 return (GET_CODE (x) == IF_THEN_ELSE 743 && ((GET_CODE (XEXP (x, 2)) == PC 744 && (GET_CODE (XEXP (x, 1)) == LABEL_REF 745 || GET_CODE (XEXP (x, 1)) == RETURN)) 746 || (GET_CODE (XEXP (x, 1)) == PC 747 && (GET_CODE (XEXP (x, 2)) == LABEL_REF 748 || GET_CODE (XEXP (x, 2)) == RETURN)))); 749 } 750 751 /* Return nonzero if INSN is a (possibly) conditional jump inside a 752 PARALLEL. 753 754 Use this function is deprecated, since we need to support combined 755 branch and compare insns. Use any_condjump_p instead whenever possible. */ 756 757 int 758 condjump_in_parallel_p (const_rtx insn) 759 { 760 const_rtx x = PATTERN (insn); 761 762 if (GET_CODE (x) != PARALLEL) 763 return 0; 764 else 765 x = XVECEXP (x, 0, 0); 766 767 if (GET_CODE (x) != SET) 768 return 0; 769 if (GET_CODE (SET_DEST (x)) != PC) 770 return 0; 771 if (GET_CODE (SET_SRC (x)) == LABEL_REF) 772 return 1; 773 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE) 774 return 0; 775 if (XEXP (SET_SRC (x), 2) == pc_rtx 776 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF 777 || GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN)) 778 return 1; 779 if (XEXP (SET_SRC (x), 1) == pc_rtx 780 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF 781 || GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN)) 782 return 1; 783 return 0; 784 } 785 786 /* Return set of PC, otherwise NULL. */ 787 788 rtx 789 pc_set (const_rtx insn) 790 { 791 rtx pat; 792 if (!JUMP_P (insn)) 793 return NULL_RTX; 794 pat = PATTERN (insn); 795 796 /* The set is allowed to appear either as the insn pattern or 797 the first set in a PARALLEL. */ 798 if (GET_CODE (pat) == PARALLEL) 799 pat = XVECEXP (pat, 0, 0); 800 if (GET_CODE (pat) == SET && GET_CODE (SET_DEST (pat)) == PC) 801 return pat; 802 803 return NULL_RTX; 804 } 805 806 /* Return true when insn is an unconditional direct jump, 807 possibly bundled inside a PARALLEL. */ 808 809 int 810 any_uncondjump_p (const_rtx insn) 811 { 812 const_rtx x = pc_set (insn); 813 if (!x) 814 return 0; 815 if (GET_CODE (SET_SRC (x)) != LABEL_REF) 816 return 0; 817 if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX)) 818 return 0; 819 return 1; 820 } 821 822 /* Return true when insn is a conditional jump. This function works for 823 instructions containing PC sets in PARALLELs. The instruction may have 824 various other effects so before removing the jump you must verify 825 onlyjump_p. 826 827 Note that unlike condjump_p it returns false for unconditional jumps. */ 828 829 int 830 any_condjump_p (const_rtx insn) 831 { 832 const_rtx x = pc_set (insn); 833 enum rtx_code a, b; 834 835 if (!x) 836 return 0; 837 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE) 838 return 0; 839 840 a = GET_CODE (XEXP (SET_SRC (x), 1)); 841 b = GET_CODE (XEXP (SET_SRC (x), 2)); 842 843 return ((b == PC && (a == LABEL_REF || a == RETURN)) 844 || (a == PC && (b == LABEL_REF || b == RETURN))); 845 } 846 847 /* Return the label of a conditional jump. */ 848 849 rtx 850 condjump_label (const_rtx insn) 851 { 852 rtx x = pc_set (insn); 853 854 if (!x) 855 return NULL_RTX; 856 x = SET_SRC (x); 857 if (GET_CODE (x) == LABEL_REF) 858 return x; 859 if (GET_CODE (x) != IF_THEN_ELSE) 860 return NULL_RTX; 861 if (XEXP (x, 2) == pc_rtx && GET_CODE (XEXP (x, 1)) == LABEL_REF) 862 return XEXP (x, 1); 863 if (XEXP (x, 1) == pc_rtx && GET_CODE (XEXP (x, 2)) == LABEL_REF) 864 return XEXP (x, 2); 865 return NULL_RTX; 866 } 867 868 /* Return true if INSN is a (possibly conditional) return insn. */ 869 870 static int 871 returnjump_p_1 (rtx *loc, void *data ATTRIBUTE_UNUSED) 872 { 873 rtx x = *loc; 874 875 if (x == NULL) 876 return false; 877 878 switch (GET_CODE (x)) 879 { 880 case RETURN: 881 case EH_RETURN: 882 return true; 883 884 case SET: 885 return SET_IS_RETURN_P (x); 886 887 default: 888 return false; 889 } 890 } 891 892 /* Return TRUE if INSN is a return jump. */ 893 894 int 895 returnjump_p (rtx insn) 896 { 897 if (!JUMP_P (insn)) 898 return 0; 899 return for_each_rtx (&PATTERN (insn), returnjump_p_1, NULL); 900 } 901 902 /* Return true if INSN is a (possibly conditional) return insn. */ 903 904 static int 905 eh_returnjump_p_1 (rtx *loc, void *data ATTRIBUTE_UNUSED) 906 { 907 return *loc && GET_CODE (*loc) == EH_RETURN; 908 } 909 910 int 911 eh_returnjump_p (rtx insn) 912 { 913 if (!JUMP_P (insn)) 914 return 0; 915 return for_each_rtx (&PATTERN (insn), eh_returnjump_p_1, NULL); 916 } 917 918 /* Return true if INSN is a jump that only transfers control and 919 nothing more. */ 920 921 int 922 onlyjump_p (const_rtx insn) 923 { 924 rtx set; 925 926 if (!JUMP_P (insn)) 927 return 0; 928 929 set = single_set (insn); 930 if (set == NULL) 931 return 0; 932 if (GET_CODE (SET_DEST (set)) != PC) 933 return 0; 934 if (side_effects_p (SET_SRC (set))) 935 return 0; 936 937 return 1; 938 } 939 940 #ifdef HAVE_cc0 941 942 /* Return nonzero if X is an RTX that only sets the condition codes 943 and has no side effects. */ 944 945 int 946 only_sets_cc0_p (const_rtx x) 947 { 948 if (! x) 949 return 0; 950 951 if (INSN_P (x)) 952 x = PATTERN (x); 953 954 return sets_cc0_p (x) == 1 && ! side_effects_p (x); 955 } 956 957 /* Return 1 if X is an RTX that does nothing but set the condition codes 958 and CLOBBER or USE registers. 959 Return -1 if X does explicitly set the condition codes, 960 but also does other things. */ 961 962 int 963 sets_cc0_p (const_rtx x) 964 { 965 if (! x) 966 return 0; 967 968 if (INSN_P (x)) 969 x = PATTERN (x); 970 971 if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx) 972 return 1; 973 if (GET_CODE (x) == PARALLEL) 974 { 975 int i; 976 int sets_cc0 = 0; 977 int other_things = 0; 978 for (i = XVECLEN (x, 0) - 1; i >= 0; i--) 979 { 980 if (GET_CODE (XVECEXP (x, 0, i)) == SET 981 && SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx) 982 sets_cc0 = 1; 983 else if (GET_CODE (XVECEXP (x, 0, i)) == SET) 984 other_things = 1; 985 } 986 return ! sets_cc0 ? 0 : other_things ? -1 : 1; 987 } 988 return 0; 989 } 990 #endif 991 992 /* Find all CODE_LABELs referred to in X, and increment their use 993 counts. If INSN is a JUMP_INSN and there is at least one 994 CODE_LABEL referenced in INSN as a jump target, then store the last 995 one in JUMP_LABEL (INSN). For a tablejump, this must be the label 996 for the ADDR_VEC. Store any other jump targets as REG_LABEL_TARGET 997 notes. If INSN is an INSN or a CALL_INSN or non-target operands of 998 a JUMP_INSN, and there is at least one CODE_LABEL referenced in 999 INSN, add a REG_LABEL_OPERAND note containing that label to INSN. 1000 1001 Note that two labels separated by a loop-beginning note 1002 must be kept distinct if we have not yet done loop-optimization, 1003 because the gap between them is where loop-optimize 1004 will want to move invariant code to. CROSS_JUMP tells us 1005 that loop-optimization is done with. */ 1006 1007 void 1008 mark_jump_label (rtx x, rtx insn, int in_mem) 1009 { 1010 rtx asmop = extract_asm_operands (x); 1011 if (asmop) 1012 mark_jump_label_asm (asmop, insn); 1013 else 1014 mark_jump_label_1 (x, insn, in_mem != 0, 1015 (insn != NULL && x == PATTERN (insn) && JUMP_P (insn))); 1016 } 1017 1018 /* Worker function for mark_jump_label. IN_MEM is TRUE when X occurs 1019 within a (MEM ...). IS_TARGET is TRUE when X is to be treated as a 1020 jump-target; when the JUMP_LABEL field of INSN should be set or a 1021 REG_LABEL_TARGET note should be added, not a REG_LABEL_OPERAND 1022 note. */ 1023 1024 static void 1025 mark_jump_label_1 (rtx x, rtx insn, bool in_mem, bool is_target) 1026 { 1027 RTX_CODE code = GET_CODE (x); 1028 int i; 1029 const char *fmt; 1030 1031 switch (code) 1032 { 1033 case PC: 1034 case CC0: 1035 case REG: 1036 case CONST_INT: 1037 case CONST_DOUBLE: 1038 case CLOBBER: 1039 case CALL: 1040 return; 1041 1042 case MEM: 1043 in_mem = true; 1044 break; 1045 1046 case SEQUENCE: 1047 for (i = 0; i < XVECLEN (x, 0); i++) 1048 mark_jump_label (PATTERN (XVECEXP (x, 0, i)), 1049 XVECEXP (x, 0, i), 0); 1050 return; 1051 1052 case SYMBOL_REF: 1053 if (!in_mem) 1054 return; 1055 1056 /* If this is a constant-pool reference, see if it is a label. */ 1057 if (CONSTANT_POOL_ADDRESS_P (x)) 1058 mark_jump_label_1 (get_pool_constant (x), insn, in_mem, is_target); 1059 break; 1060 1061 /* Handle operands in the condition of an if-then-else as for a 1062 non-jump insn. */ 1063 case IF_THEN_ELSE: 1064 if (!is_target) 1065 break; 1066 mark_jump_label_1 (XEXP (x, 0), insn, in_mem, false); 1067 mark_jump_label_1 (XEXP (x, 1), insn, in_mem, true); 1068 mark_jump_label_1 (XEXP (x, 2), insn, in_mem, true); 1069 return; 1070 1071 case LABEL_REF: 1072 { 1073 rtx label = XEXP (x, 0); 1074 1075 /* Ignore remaining references to unreachable labels that 1076 have been deleted. */ 1077 if (NOTE_P (label) 1078 && NOTE_KIND (label) == NOTE_INSN_DELETED_LABEL) 1079 break; 1080 1081 gcc_assert (LABEL_P (label)); 1082 1083 /* Ignore references to labels of containing functions. */ 1084 if (LABEL_REF_NONLOCAL_P (x)) 1085 break; 1086 1087 XEXP (x, 0) = label; 1088 if (! insn || ! INSN_DELETED_P (insn)) 1089 ++LABEL_NUSES (label); 1090 1091 if (insn) 1092 { 1093 if (is_target 1094 /* Do not change a previous setting of JUMP_LABEL. If the 1095 JUMP_LABEL slot is occupied by a different label, 1096 create a note for this label. */ 1097 && (JUMP_LABEL (insn) == NULL || JUMP_LABEL (insn) == label)) 1098 JUMP_LABEL (insn) = label; 1099 else 1100 { 1101 enum reg_note kind 1102 = is_target ? REG_LABEL_TARGET : REG_LABEL_OPERAND; 1103 1104 /* Add a REG_LABEL_OPERAND or REG_LABEL_TARGET note 1105 for LABEL unless there already is one. All uses of 1106 a label, except for the primary target of a jump, 1107 must have such a note. */ 1108 if (! find_reg_note (insn, kind, label)) 1109 add_reg_note (insn, kind, label); 1110 } 1111 } 1112 return; 1113 } 1114 1115 /* Do walk the labels in a vector, but not the first operand of an 1116 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */ 1117 case ADDR_VEC: 1118 case ADDR_DIFF_VEC: 1119 if (! INSN_DELETED_P (insn)) 1120 { 1121 int eltnum = code == ADDR_DIFF_VEC ? 1 : 0; 1122 1123 for (i = 0; i < XVECLEN (x, eltnum); i++) 1124 mark_jump_label_1 (XVECEXP (x, eltnum, i), NULL_RTX, in_mem, 1125 is_target); 1126 } 1127 return; 1128 1129 default: 1130 break; 1131 } 1132 1133 fmt = GET_RTX_FORMAT (code); 1134 1135 /* The primary target of a tablejump is the label of the ADDR_VEC, 1136 which is canonically mentioned *last* in the insn. To get it 1137 marked as JUMP_LABEL, we iterate over items in reverse order. */ 1138 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) 1139 { 1140 if (fmt[i] == 'e') 1141 mark_jump_label_1 (XEXP (x, i), insn, in_mem, is_target); 1142 else if (fmt[i] == 'E') 1143 { 1144 int j; 1145 1146 for (j = XVECLEN (x, i) - 1; j >= 0; j--) 1147 mark_jump_label_1 (XVECEXP (x, i, j), insn, in_mem, 1148 is_target); 1149 } 1150 } 1151 } 1152 1153 /* Worker function for mark_jump_label. Handle asm insns specially. 1154 In particular, output operands need not be considered so we can 1155 avoid re-scanning the replicated asm_operand. Also, the asm_labels 1156 need to be considered targets. */ 1157 1158 static void 1159 mark_jump_label_asm (rtx asmop, rtx insn) 1160 { 1161 int i; 1162 1163 for (i = ASM_OPERANDS_INPUT_LENGTH (asmop) - 1; i >= 0; --i) 1164 mark_jump_label_1 (ASM_OPERANDS_INPUT (asmop, i), insn, false, false); 1165 1166 for (i = ASM_OPERANDS_LABEL_LENGTH (asmop) - 1; i >= 0; --i) 1167 mark_jump_label_1 (ASM_OPERANDS_LABEL (asmop, i), insn, false, true); 1168 } 1169 1170 /* Delete insn INSN from the chain of insns and update label ref counts 1171 and delete insns now unreachable. 1172 1173 Returns the first insn after INSN that was not deleted. 1174 1175 Usage of this instruction is deprecated. Use delete_insn instead and 1176 subsequent cfg_cleanup pass to delete unreachable code if needed. */ 1177 1178 rtx 1179 delete_related_insns (rtx insn) 1180 { 1181 int was_code_label = (LABEL_P (insn)); 1182 rtx note; 1183 rtx next = NEXT_INSN (insn), prev = PREV_INSN (insn); 1184 1185 while (next && INSN_DELETED_P (next)) 1186 next = NEXT_INSN (next); 1187 1188 /* This insn is already deleted => return first following nondeleted. */ 1189 if (INSN_DELETED_P (insn)) 1190 return next; 1191 1192 delete_insn (insn); 1193 1194 /* If instruction is followed by a barrier, 1195 delete the barrier too. */ 1196 1197 if (next != 0 && BARRIER_P (next)) 1198 delete_insn (next); 1199 1200 /* If deleting a jump, decrement the count of the label, 1201 and delete the label if it is now unused. */ 1202 1203 if (JUMP_P (insn) && JUMP_LABEL (insn)) 1204 { 1205 rtx lab = JUMP_LABEL (insn), lab_next; 1206 1207 if (LABEL_NUSES (lab) == 0) 1208 /* This can delete NEXT or PREV, 1209 either directly if NEXT is JUMP_LABEL (INSN), 1210 or indirectly through more levels of jumps. */ 1211 delete_related_insns (lab); 1212 else if (tablejump_p (insn, NULL, &lab_next)) 1213 { 1214 /* If we're deleting the tablejump, delete the dispatch table. 1215 We may not be able to kill the label immediately preceding 1216 just yet, as it might be referenced in code leading up to 1217 the tablejump. */ 1218 delete_related_insns (lab_next); 1219 } 1220 } 1221 1222 /* Likewise if we're deleting a dispatch table. */ 1223 1224 if (JUMP_TABLE_DATA_P (insn)) 1225 { 1226 rtx pat = PATTERN (insn); 1227 int i, diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC; 1228 int len = XVECLEN (pat, diff_vec_p); 1229 1230 for (i = 0; i < len; i++) 1231 if (LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0) 1232 delete_related_insns (XEXP (XVECEXP (pat, diff_vec_p, i), 0)); 1233 while (next && INSN_DELETED_P (next)) 1234 next = NEXT_INSN (next); 1235 return next; 1236 } 1237 1238 /* Likewise for any JUMP_P / INSN / CALL_INSN with a 1239 REG_LABEL_OPERAND or REG_LABEL_TARGET note. */ 1240 if (INSN_P (insn)) 1241 for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) 1242 if ((REG_NOTE_KIND (note) == REG_LABEL_OPERAND 1243 || REG_NOTE_KIND (note) == REG_LABEL_TARGET) 1244 /* This could also be a NOTE_INSN_DELETED_LABEL note. */ 1245 && LABEL_P (XEXP (note, 0))) 1246 if (LABEL_NUSES (XEXP (note, 0)) == 0) 1247 delete_related_insns (XEXP (note, 0)); 1248 1249 while (prev && (INSN_DELETED_P (prev) || NOTE_P (prev))) 1250 prev = PREV_INSN (prev); 1251 1252 /* If INSN was a label and a dispatch table follows it, 1253 delete the dispatch table. The tablejump must have gone already. 1254 It isn't useful to fall through into a table. */ 1255 1256 if (was_code_label 1257 && NEXT_INSN (insn) != 0 1258 && JUMP_TABLE_DATA_P (NEXT_INSN (insn))) 1259 next = delete_related_insns (NEXT_INSN (insn)); 1260 1261 /* If INSN was a label, delete insns following it if now unreachable. */ 1262 1263 if (was_code_label && prev && BARRIER_P (prev)) 1264 { 1265 enum rtx_code code; 1266 while (next) 1267 { 1268 code = GET_CODE (next); 1269 if (code == NOTE) 1270 next = NEXT_INSN (next); 1271 /* Keep going past other deleted labels to delete what follows. */ 1272 else if (code == CODE_LABEL && INSN_DELETED_P (next)) 1273 next = NEXT_INSN (next); 1274 else if (code == BARRIER || INSN_P (next)) 1275 /* Note: if this deletes a jump, it can cause more 1276 deletion of unreachable code, after a different label. 1277 As long as the value from this recursive call is correct, 1278 this invocation functions correctly. */ 1279 next = delete_related_insns (next); 1280 else 1281 break; 1282 } 1283 } 1284 1285 /* I feel a little doubtful about this loop, 1286 but I see no clean and sure alternative way 1287 to find the first insn after INSN that is not now deleted. 1288 I hope this works. */ 1289 while (next && INSN_DELETED_P (next)) 1290 next = NEXT_INSN (next); 1291 return next; 1292 } 1293 1294 /* Delete a range of insns from FROM to TO, inclusive. 1295 This is for the sake of peephole optimization, so assume 1296 that whatever these insns do will still be done by a new 1297 peephole insn that will replace them. */ 1298 1299 void 1300 delete_for_peephole (rtx from, rtx to) 1301 { 1302 rtx insn = from; 1303 1304 while (1) 1305 { 1306 rtx next = NEXT_INSN (insn); 1307 rtx prev = PREV_INSN (insn); 1308 1309 if (!NOTE_P (insn)) 1310 { 1311 INSN_DELETED_P (insn) = 1; 1312 1313 /* Patch this insn out of the chain. */ 1314 /* We don't do this all at once, because we 1315 must preserve all NOTEs. */ 1316 if (prev) 1317 NEXT_INSN (prev) = next; 1318 1319 if (next) 1320 PREV_INSN (next) = prev; 1321 } 1322 1323 if (insn == to) 1324 break; 1325 insn = next; 1326 } 1327 1328 /* Note that if TO is an unconditional jump 1329 we *do not* delete the BARRIER that follows, 1330 since the peephole that replaces this sequence 1331 is also an unconditional jump in that case. */ 1332 } 1333 1334 /* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or 1335 NLABEL as a return. Accrue modifications into the change group. */ 1336 1337 static void 1338 redirect_exp_1 (rtx *loc, rtx olabel, rtx nlabel, rtx insn) 1339 { 1340 rtx x = *loc; 1341 RTX_CODE code = GET_CODE (x); 1342 int i; 1343 const char *fmt; 1344 1345 if (code == LABEL_REF) 1346 { 1347 if (XEXP (x, 0) == olabel) 1348 { 1349 rtx n; 1350 if (nlabel) 1351 n = gen_rtx_LABEL_REF (Pmode, nlabel); 1352 else 1353 n = gen_rtx_RETURN (VOIDmode); 1354 1355 validate_change (insn, loc, n, 1); 1356 return; 1357 } 1358 } 1359 else if (code == RETURN && olabel == 0) 1360 { 1361 if (nlabel) 1362 x = gen_rtx_LABEL_REF (Pmode, nlabel); 1363 else 1364 x = gen_rtx_RETURN (VOIDmode); 1365 if (loc == &PATTERN (insn)) 1366 x = gen_rtx_SET (VOIDmode, pc_rtx, x); 1367 validate_change (insn, loc, x, 1); 1368 return; 1369 } 1370 1371 if (code == SET && nlabel == 0 && SET_DEST (x) == pc_rtx 1372 && GET_CODE (SET_SRC (x)) == LABEL_REF 1373 && XEXP (SET_SRC (x), 0) == olabel) 1374 { 1375 validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 1); 1376 return; 1377 } 1378 1379 if (code == IF_THEN_ELSE) 1380 { 1381 /* Skip the condition of an IF_THEN_ELSE. We only want to 1382 change jump destinations, not eventual label comparisons. */ 1383 redirect_exp_1 (&XEXP (x, 1), olabel, nlabel, insn); 1384 redirect_exp_1 (&XEXP (x, 2), olabel, nlabel, insn); 1385 return; 1386 } 1387 1388 fmt = GET_RTX_FORMAT (code); 1389 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) 1390 { 1391 if (fmt[i] == 'e') 1392 redirect_exp_1 (&XEXP (x, i), olabel, nlabel, insn); 1393 else if (fmt[i] == 'E') 1394 { 1395 int j; 1396 for (j = 0; j < XVECLEN (x, i); j++) 1397 redirect_exp_1 (&XVECEXP (x, i, j), olabel, nlabel, insn); 1398 } 1399 } 1400 } 1401 1402 /* Make JUMP go to NLABEL instead of where it jumps now. Accrue 1403 the modifications into the change group. Return false if we did 1404 not see how to do that. */ 1405 1406 int 1407 redirect_jump_1 (rtx jump, rtx nlabel) 1408 { 1409 int ochanges = num_validated_changes (); 1410 rtx *loc, asmop; 1411 1412 asmop = extract_asm_operands (PATTERN (jump)); 1413 if (asmop) 1414 { 1415 if (nlabel == NULL) 1416 return 0; 1417 gcc_assert (ASM_OPERANDS_LABEL_LENGTH (asmop) == 1); 1418 loc = &ASM_OPERANDS_LABEL (asmop, 0); 1419 } 1420 else if (GET_CODE (PATTERN (jump)) == PARALLEL) 1421 loc = &XVECEXP (PATTERN (jump), 0, 0); 1422 else 1423 loc = &PATTERN (jump); 1424 1425 redirect_exp_1 (loc, JUMP_LABEL (jump), nlabel, jump); 1426 return num_validated_changes () > ochanges; 1427 } 1428 1429 /* Make JUMP go to NLABEL instead of where it jumps now. If the old 1430 jump target label is unused as a result, it and the code following 1431 it may be deleted. 1432 1433 If NLABEL is zero, we are to turn the jump into a (possibly conditional) 1434 RETURN insn. 1435 1436 The return value will be 1 if the change was made, 0 if it wasn't 1437 (this can only occur for NLABEL == 0). */ 1438 1439 int 1440 redirect_jump (rtx jump, rtx nlabel, int delete_unused) 1441 { 1442 rtx olabel = JUMP_LABEL (jump); 1443 1444 if (nlabel == olabel) 1445 return 1; 1446 1447 if (! redirect_jump_1 (jump, nlabel) || ! apply_change_group ()) 1448 return 0; 1449 1450 redirect_jump_2 (jump, olabel, nlabel, delete_unused, 0); 1451 return 1; 1452 } 1453 1454 /* Fix up JUMP_LABEL and label ref counts after OLABEL has been replaced with 1455 NLABEL in JUMP. 1456 If DELETE_UNUSED is positive, delete related insn to OLABEL if its ref 1457 count has dropped to zero. */ 1458 void 1459 redirect_jump_2 (rtx jump, rtx olabel, rtx nlabel, int delete_unused, 1460 int invert) 1461 { 1462 rtx note; 1463 1464 gcc_assert (JUMP_LABEL (jump) == olabel); 1465 1466 /* Negative DELETE_UNUSED used to be used to signalize behavior on 1467 moving FUNCTION_END note. Just sanity check that no user still worry 1468 about this. */ 1469 gcc_assert (delete_unused >= 0); 1470 JUMP_LABEL (jump) = nlabel; 1471 if (nlabel) 1472 ++LABEL_NUSES (nlabel); 1473 1474 /* Update labels in any REG_EQUAL note. */ 1475 if ((note = find_reg_note (jump, REG_EQUAL, NULL_RTX)) != NULL_RTX) 1476 { 1477 if (!nlabel || (invert && !invert_exp_1 (XEXP (note, 0), jump))) 1478 remove_note (jump, note); 1479 else 1480 { 1481 redirect_exp_1 (&XEXP (note, 0), olabel, nlabel, jump); 1482 confirm_change_group (); 1483 } 1484 } 1485 1486 if (olabel && --LABEL_NUSES (olabel) == 0 && delete_unused > 0 1487 /* Undefined labels will remain outside the insn stream. */ 1488 && INSN_UID (olabel)) 1489 delete_related_insns (olabel); 1490 if (invert) 1491 invert_br_probabilities (jump); 1492 } 1493 1494 /* Invert the jump condition X contained in jump insn INSN. Accrue the 1495 modifications into the change group. Return nonzero for success. */ 1496 static int 1497 invert_exp_1 (rtx x, rtx insn) 1498 { 1499 RTX_CODE code = GET_CODE (x); 1500 1501 if (code == IF_THEN_ELSE) 1502 { 1503 rtx comp = XEXP (x, 0); 1504 rtx tem; 1505 enum rtx_code reversed_code; 1506 1507 /* We can do this in two ways: The preferable way, which can only 1508 be done if this is not an integer comparison, is to reverse 1509 the comparison code. Otherwise, swap the THEN-part and ELSE-part 1510 of the IF_THEN_ELSE. If we can't do either, fail. */ 1511 1512 reversed_code = reversed_comparison_code (comp, insn); 1513 1514 if (reversed_code != UNKNOWN) 1515 { 1516 validate_change (insn, &XEXP (x, 0), 1517 gen_rtx_fmt_ee (reversed_code, 1518 GET_MODE (comp), XEXP (comp, 0), 1519 XEXP (comp, 1)), 1520 1); 1521 return 1; 1522 } 1523 1524 tem = XEXP (x, 1); 1525 validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1); 1526 validate_change (insn, &XEXP (x, 2), tem, 1); 1527 return 1; 1528 } 1529 else 1530 return 0; 1531 } 1532 1533 /* Invert the condition of the jump JUMP, and make it jump to label 1534 NLABEL instead of where it jumps now. Accrue changes into the 1535 change group. Return false if we didn't see how to perform the 1536 inversion and redirection. */ 1537 1538 int 1539 invert_jump_1 (rtx jump, rtx nlabel) 1540 { 1541 rtx x = pc_set (jump); 1542 int ochanges; 1543 int ok; 1544 1545 ochanges = num_validated_changes (); 1546 if (x == NULL) 1547 return 0; 1548 ok = invert_exp_1 (SET_SRC (x), jump); 1549 gcc_assert (ok); 1550 1551 if (num_validated_changes () == ochanges) 1552 return 0; 1553 1554 /* redirect_jump_1 will fail of nlabel == olabel, and the current use is 1555 in Pmode, so checking this is not merely an optimization. */ 1556 return nlabel == JUMP_LABEL (jump) || redirect_jump_1 (jump, nlabel); 1557 } 1558 1559 /* Invert the condition of the jump JUMP, and make it jump to label 1560 NLABEL instead of where it jumps now. Return true if successful. */ 1561 1562 int 1563 invert_jump (rtx jump, rtx nlabel, int delete_unused) 1564 { 1565 rtx olabel = JUMP_LABEL (jump); 1566 1567 if (invert_jump_1 (jump, nlabel) && apply_change_group ()) 1568 { 1569 redirect_jump_2 (jump, olabel, nlabel, delete_unused, 1); 1570 return 1; 1571 } 1572 cancel_changes (0); 1573 return 0; 1574 } 1575 1576 1577 /* Like rtx_equal_p except that it considers two REGs as equal 1578 if they renumber to the same value and considers two commutative 1579 operations to be the same if the order of the operands has been 1580 reversed. */ 1581 1582 int 1583 rtx_renumbered_equal_p (const_rtx x, const_rtx y) 1584 { 1585 int i; 1586 const enum rtx_code code = GET_CODE (x); 1587 const char *fmt; 1588 1589 if (x == y) 1590 return 1; 1591 1592 if ((code == REG || (code == SUBREG && REG_P (SUBREG_REG (x)))) 1593 && (REG_P (y) || (GET_CODE (y) == SUBREG 1594 && REG_P (SUBREG_REG (y))))) 1595 { 1596 int reg_x = -1, reg_y = -1; 1597 int byte_x = 0, byte_y = 0; 1598 struct subreg_info info; 1599 1600 if (GET_MODE (x) != GET_MODE (y)) 1601 return 0; 1602 1603 /* If we haven't done any renumbering, don't 1604 make any assumptions. */ 1605 if (reg_renumber == 0) 1606 return rtx_equal_p (x, y); 1607 1608 if (code == SUBREG) 1609 { 1610 reg_x = REGNO (SUBREG_REG (x)); 1611 byte_x = SUBREG_BYTE (x); 1612 1613 if (reg_renumber[reg_x] >= 0) 1614 { 1615 subreg_get_info (reg_renumber[reg_x], 1616 GET_MODE (SUBREG_REG (x)), byte_x, 1617 GET_MODE (x), &info); 1618 if (!info.representable_p) 1619 return 0; 1620 reg_x = info.offset; 1621 byte_x = 0; 1622 } 1623 } 1624 else 1625 { 1626 reg_x = REGNO (x); 1627 if (reg_renumber[reg_x] >= 0) 1628 reg_x = reg_renumber[reg_x]; 1629 } 1630 1631 if (GET_CODE (y) == SUBREG) 1632 { 1633 reg_y = REGNO (SUBREG_REG (y)); 1634 byte_y = SUBREG_BYTE (y); 1635 1636 if (reg_renumber[reg_y] >= 0) 1637 { 1638 subreg_get_info (reg_renumber[reg_y], 1639 GET_MODE (SUBREG_REG (y)), byte_y, 1640 GET_MODE (y), &info); 1641 if (!info.representable_p) 1642 return 0; 1643 reg_y = info.offset; 1644 byte_y = 0; 1645 } 1646 } 1647 else 1648 { 1649 reg_y = REGNO (y); 1650 if (reg_renumber[reg_y] >= 0) 1651 reg_y = reg_renumber[reg_y]; 1652 } 1653 1654 return reg_x >= 0 && reg_x == reg_y && byte_x == byte_y; 1655 } 1656 1657 /* Now we have disposed of all the cases 1658 in which different rtx codes can match. */ 1659 if (code != GET_CODE (y)) 1660 return 0; 1661 1662 switch (code) 1663 { 1664 case PC: 1665 case CC0: 1666 case ADDR_VEC: 1667 case ADDR_DIFF_VEC: 1668 case CONST_INT: 1669 case CONST_DOUBLE: 1670 return 0; 1671 1672 case LABEL_REF: 1673 /* We can't assume nonlocal labels have their following insns yet. */ 1674 if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y)) 1675 return XEXP (x, 0) == XEXP (y, 0); 1676 1677 /* Two label-refs are equivalent if they point at labels 1678 in the same position in the instruction stream. */ 1679 return (next_real_insn (XEXP (x, 0)) 1680 == next_real_insn (XEXP (y, 0))); 1681 1682 case SYMBOL_REF: 1683 return XSTR (x, 0) == XSTR (y, 0); 1684 1685 case CODE_LABEL: 1686 /* If we didn't match EQ equality above, they aren't the same. */ 1687 return 0; 1688 1689 default: 1690 break; 1691 } 1692 1693 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */ 1694 1695 if (GET_MODE (x) != GET_MODE (y)) 1696 return 0; 1697 1698 /* MEMs refering to different address space are not equivalent. */ 1699 if (code == MEM && MEM_ADDR_SPACE (x) != MEM_ADDR_SPACE (y)) 1700 return 0; 1701 1702 /* For commutative operations, the RTX match if the operand match in any 1703 order. Also handle the simple binary and unary cases without a loop. */ 1704 if (targetm.commutative_p (x, UNKNOWN)) 1705 return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0)) 1706 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1))) 1707 || (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1)) 1708 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0)))); 1709 else if (NON_COMMUTATIVE_P (x)) 1710 return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0)) 1711 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1))); 1712 else if (UNARY_P (x)) 1713 return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0)); 1714 1715 /* Compare the elements. If any pair of corresponding elements 1716 fail to match, return 0 for the whole things. */ 1717 1718 fmt = GET_RTX_FORMAT (code); 1719 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) 1720 { 1721 int j; 1722 switch (fmt[i]) 1723 { 1724 case 'w': 1725 if (XWINT (x, i) != XWINT (y, i)) 1726 return 0; 1727 break; 1728 1729 case 'i': 1730 if (XINT (x, i) != XINT (y, i)) 1731 { 1732 if (((code == ASM_OPERANDS && i == 6) 1733 || (code == ASM_INPUT && i == 1)) 1734 && locator_eq (XINT (x, i), XINT (y, i))) 1735 break; 1736 return 0; 1737 } 1738 break; 1739 1740 case 't': 1741 if (XTREE (x, i) != XTREE (y, i)) 1742 return 0; 1743 break; 1744 1745 case 's': 1746 if (strcmp (XSTR (x, i), XSTR (y, i))) 1747 return 0; 1748 break; 1749 1750 case 'e': 1751 if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i))) 1752 return 0; 1753 break; 1754 1755 case 'u': 1756 if (XEXP (x, i) != XEXP (y, i)) 1757 return 0; 1758 /* Fall through. */ 1759 case '0': 1760 break; 1761 1762 case 'E': 1763 if (XVECLEN (x, i) != XVECLEN (y, i)) 1764 return 0; 1765 for (j = XVECLEN (x, i) - 1; j >= 0; j--) 1766 if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j))) 1767 return 0; 1768 break; 1769 1770 default: 1771 gcc_unreachable (); 1772 } 1773 } 1774 return 1; 1775 } 1776 1777 /* If X is a hard register or equivalent to one or a subregister of one, 1778 return the hard register number. If X is a pseudo register that was not 1779 assigned a hard register, return the pseudo register number. Otherwise, 1780 return -1. Any rtx is valid for X. */ 1781 1782 int 1783 true_regnum (const_rtx x) 1784 { 1785 if (REG_P (x)) 1786 { 1787 if (REGNO (x) >= FIRST_PSEUDO_REGISTER && reg_renumber[REGNO (x)] >= 0) 1788 return reg_renumber[REGNO (x)]; 1789 return REGNO (x); 1790 } 1791 if (GET_CODE (x) == SUBREG) 1792 { 1793 int base = true_regnum (SUBREG_REG (x)); 1794 if (base >= 0 1795 && base < FIRST_PSEUDO_REGISTER) 1796 { 1797 struct subreg_info info; 1798 1799 subreg_get_info (REGNO (SUBREG_REG (x)), 1800 GET_MODE (SUBREG_REG (x)), 1801 SUBREG_BYTE (x), GET_MODE (x), &info); 1802 1803 if (info.representable_p) 1804 return base + info.offset; 1805 } 1806 } 1807 return -1; 1808 } 1809 1810 /* Return regno of the register REG and handle subregs too. */ 1811 unsigned int 1812 reg_or_subregno (const_rtx reg) 1813 { 1814 if (GET_CODE (reg) == SUBREG) 1815 reg = SUBREG_REG (reg); 1816 gcc_assert (REG_P (reg)); 1817 return REGNO (reg); 1818 } 1819