1 /* Basic block reordering routines for the GNU compiler.
2 Copyright (C) 2000, 2001, 2003, 2004, 2005 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 2, or (at your option) any later
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to the Free
18 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
23 #include "coretypes.h"
27 #include "hard-reg-set.h"
29 #include "basic-block.h"
30 #include "insn-config.h"
33 #include "cfglayout.h"
37 #include "alloc-pool.h"
40 /* Holds the interesting trailing notes for the function. */
41 rtx cfg_layout_function_footer, cfg_layout_function_header;
43 static rtx skip_insns_after_block (basic_block);
44 static void record_effective_endpoints (void);
45 static rtx label_for_bb (basic_block);
46 static void fixup_reorder_chain (void);
48 static void set_block_levels (tree, int);
49 static void change_scope (rtx, tree, tree);
51 void verify_insn_chain (void);
52 static void fixup_fallthru_exit_predecessor (void);
53 static tree insn_scope (rtx);
56 unlink_insn_chain (rtx first, rtx last)
58 rtx prevfirst = PREV_INSN (first);
59 rtx nextlast = NEXT_INSN (last);
61 PREV_INSN (first) = NULL;
62 NEXT_INSN (last) = NULL;
64 NEXT_INSN (prevfirst) = nextlast;
66 PREV_INSN (nextlast) = prevfirst;
68 set_last_insn (prevfirst);
70 set_first_insn (nextlast);
74 /* Skip over inter-block insns occurring after BB which are typically
75 associated with BB (e.g., barriers). If there are any such insns,
76 we return the last one. Otherwise, we return the end of BB. */
79 skip_insns_after_block (basic_block bb)
81 rtx insn, last_insn, next_head, prev;
84 if (bb->next_bb != EXIT_BLOCK_PTR)
85 next_head = BB_HEAD (bb->next_bb);
87 for (last_insn = insn = BB_END (bb); (insn = NEXT_INSN (insn)) != 0; )
89 if (insn == next_head)
92 switch (GET_CODE (insn))
99 switch (NOTE_LINE_NUMBER (insn))
101 case NOTE_INSN_LOOP_END:
102 case NOTE_INSN_BLOCK_END:
105 case NOTE_INSN_DELETED:
106 case NOTE_INSN_DELETED_LABEL:
117 && JUMP_P (NEXT_INSN (insn))
118 && (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
119 || GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
121 insn = NEXT_INSN (insn);
134 /* It is possible to hit contradictory sequence. For instance:
140 Where barrier belongs to jump_insn, but the note does not. This can be
141 created by removing the basic block originally following
142 NOTE_INSN_LOOP_BEG. In such case reorder the notes. */
144 for (insn = last_insn; insn != BB_END (bb); insn = prev)
146 prev = PREV_INSN (insn);
148 switch (NOTE_LINE_NUMBER (insn))
150 case NOTE_INSN_LOOP_END:
151 case NOTE_INSN_BLOCK_END:
152 case NOTE_INSN_DELETED:
153 case NOTE_INSN_DELETED_LABEL:
156 reorder_insns (insn, insn, last_insn);
163 /* Locate or create a label for a given basic block. */
166 label_for_bb (basic_block bb)
168 rtx label = BB_HEAD (bb);
170 if (!LABEL_P (label))
173 fprintf (dump_file, "Emitting label for block %d\n", bb->index);
175 label = block_label (bb);
181 /* Locate the effective beginning and end of the insn chain for each
182 block, as defined by skip_insns_after_block above. */
185 record_effective_endpoints (void)
191 for (insn = get_insns ();
194 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_BASIC_BLOCK;
195 insn = NEXT_INSN (insn))
197 /* No basic blocks at all? */
200 if (PREV_INSN (insn))
201 cfg_layout_function_header =
202 unlink_insn_chain (get_insns (), PREV_INSN (insn));
204 cfg_layout_function_header = NULL_RTX;
206 next_insn = get_insns ();
211 if (PREV_INSN (BB_HEAD (bb)) && next_insn != BB_HEAD (bb))
212 bb->il.rtl->header = unlink_insn_chain (next_insn,
213 PREV_INSN (BB_HEAD (bb)));
214 end = skip_insns_after_block (bb);
215 if (NEXT_INSN (BB_END (bb)) && BB_END (bb) != end)
216 bb->il.rtl->footer = unlink_insn_chain (NEXT_INSN (BB_END (bb)), end);
217 next_insn = NEXT_INSN (BB_END (bb));
220 cfg_layout_function_footer = next_insn;
221 if (cfg_layout_function_footer)
222 cfg_layout_function_footer = unlink_insn_chain (cfg_layout_function_footer, get_last_insn ());
226 DEF_VEC_ALLOC_I(int,heap);
228 /* Data structures representing mapping of INSN_LOCATOR into scope blocks, line
229 numbers and files. In order to be GGC friendly we need to use separate
230 varrays. This also slightly improve the memory locality in binary search.
231 The _locs array contains locators where the given property change. The
232 block_locators_blocks contains the scope block that is used for all insn
233 locator greater than corresponding block_locators_locs value and smaller
234 than the following one. Similarly for the other properties. */
235 static VEC(int,heap) *block_locators_locs;
236 static GTY(()) VEC(tree,gc) *block_locators_blocks;
237 static VEC(int,heap) *line_locators_locs;
238 static VEC(int,heap) *line_locators_lines;
239 static VEC(int,heap) *file_locators_locs;
240 static GTY(()) varray_type file_locators_files;
241 int prologue_locator;
242 int epilogue_locator;
244 /* During the RTL expansion the lexical blocks and line numbers are
245 represented via INSN_NOTEs. Replace them by representation using
249 insn_locators_initialize (void)
252 tree last_block = NULL;
255 int line_number = 0, last_line_number = 0;
256 const char *file_name = NULL, *last_file_name = NULL;
258 prologue_locator = epilogue_locator = 0;
260 block_locators_locs = VEC_alloc (int, heap, 32);
261 block_locators_blocks = VEC_alloc (tree, gc, 32);
262 line_locators_locs = VEC_alloc (int, heap, 32);
263 line_locators_lines = VEC_alloc (int, heap, 32);
264 file_locators_locs = VEC_alloc (int, heap, 32);
265 VARRAY_CHAR_PTR_INIT (file_locators_files, 32, "file_locators_files");
267 for (insn = get_insns (); insn; insn = next)
271 next = NEXT_INSN (insn);
275 gcc_assert (NOTE_LINE_NUMBER (insn) != NOTE_INSN_BLOCK_BEG
276 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_BLOCK_END);
277 if (NOTE_LINE_NUMBER (insn) > 0)
279 expanded_location xloc;
280 NOTE_EXPANDED_LOCATION (xloc, insn);
281 line_number = xloc.line;
282 file_name = xloc.file;
286 active = (active_insn_p (insn)
287 && GET_CODE (PATTERN (insn)) != ADDR_VEC
288 && GET_CODE (PATTERN (insn)) != ADDR_DIFF_VEC);
290 check_block_change (insn, &block);
294 || (!prologue_locator && file_name))
296 if (last_block != block)
299 VEC_safe_push (int, heap, block_locators_locs, loc);
300 VEC_safe_push (tree, gc, block_locators_blocks, block);
303 if (last_line_number != line_number)
306 VEC_safe_push (int, heap, line_locators_locs, loc);
307 VEC_safe_push (int, heap, line_locators_lines, line_number);
308 last_line_number = line_number;
310 if (last_file_name != file_name)
313 VEC_safe_push (int, heap, file_locators_locs, loc);
314 VARRAY_PUSH_CHAR_PTR (file_locators_files, (char *) file_name);
315 last_file_name = file_name;
317 if (!prologue_locator && file_name)
318 prologue_locator = loc;
320 epilogue_locator = loc;
322 INSN_LOCATOR (insn) = loc;
326 /* Tag the blocks with a depth number so that change_scope can find
327 the common parent easily. */
328 set_block_levels (DECL_INITIAL (cfun->decl), 0);
330 free_block_changes ();
333 /* For each lexical block, set BLOCK_NUMBER to the depth at which it is
334 found in the block tree. */
337 set_block_levels (tree block, int level)
341 BLOCK_NUMBER (block) = level;
342 set_block_levels (BLOCK_SUBBLOCKS (block), level + 1);
343 block = BLOCK_CHAIN (block);
347 /* Return sope resulting from combination of S1 and S2. */
349 choose_inner_scope (tree s1, tree s2)
355 if (BLOCK_NUMBER (s1) > BLOCK_NUMBER (s2))
360 /* Emit lexical block notes needed to change scope from S1 to S2. */
363 change_scope (rtx orig_insn, tree s1, tree s2)
365 rtx insn = orig_insn;
366 tree com = NULL_TREE;
367 tree ts1 = s1, ts2 = s2;
372 gcc_assert (ts1 && ts2);
373 if (BLOCK_NUMBER (ts1) > BLOCK_NUMBER (ts2))
374 ts1 = BLOCK_SUPERCONTEXT (ts1);
375 else if (BLOCK_NUMBER (ts1) < BLOCK_NUMBER (ts2))
376 ts2 = BLOCK_SUPERCONTEXT (ts2);
379 ts1 = BLOCK_SUPERCONTEXT (ts1);
380 ts2 = BLOCK_SUPERCONTEXT (ts2);
389 rtx note = emit_note_before (NOTE_INSN_BLOCK_END, insn);
390 NOTE_BLOCK (note) = s;
391 s = BLOCK_SUPERCONTEXT (s);
398 insn = emit_note_before (NOTE_INSN_BLOCK_BEG, insn);
399 NOTE_BLOCK (insn) = s;
400 s = BLOCK_SUPERCONTEXT (s);
404 /* Return lexical scope block insn belong to. */
406 insn_scope (rtx insn)
408 int max = VEC_length (int, block_locators_locs);
410 int loc = INSN_LOCATOR (insn);
412 /* When block_locators_locs was initialized, the pro- and epilogue
413 insns didn't exist yet and can therefore not be found this way.
414 But we know that they belong to the outer most block of the
416 Without this test, the prologue would be put inside the block of
417 the first valid instruction in the function and when that first
418 insn is part of an inlined function then the low_pc of that
419 inlined function is messed up. Likewise for the epilogue and
420 the last valid instruction. */
421 if (loc == prologue_locator || loc == epilogue_locator)
422 return DECL_INITIAL (cfun->decl);
428 int pos = (min + max) / 2;
429 int tmp = VEC_index (int, block_locators_locs, pos);
431 if (tmp <= loc && min != pos)
433 else if (tmp > loc && max != pos)
441 return VEC_index (tree, block_locators_blocks, min);
444 /* Return line number of the statement specified by the locator. */
446 locator_line (int loc)
448 int max = VEC_length (int, line_locators_locs);
455 int pos = (min + max) / 2;
456 int tmp = VEC_index (int, line_locators_locs, pos);
458 if (tmp <= loc && min != pos)
460 else if (tmp > loc && max != pos)
468 return VEC_index (int, line_locators_lines, min);
471 /* Return line number of the statement that produced this insn. */
475 return locator_line (INSN_LOCATOR (insn));
478 /* Return source file of the statement specified by LOC. */
480 locator_file (int loc)
482 int max = VEC_length (int, file_locators_locs);
489 int pos = (min + max) / 2;
490 int tmp = VEC_index (int, file_locators_locs, pos);
492 if (tmp <= loc && min != pos)
494 else if (tmp > loc && max != pos)
502 return VARRAY_CHAR_PTR (file_locators_files, min);
505 /* Return source file of the statement that produced this insn. */
509 return locator_file (INSN_LOCATOR (insn));
512 /* Rebuild all the NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes based
513 on the scope tree and the newly reordered instructions. */
516 reemit_insn_block_notes (void)
518 tree cur_block = DECL_INITIAL (cfun->decl);
522 if (!active_insn_p (insn))
523 insn = next_active_insn (insn);
524 for (; insn; insn = next_active_insn (insn))
528 /* Avoid putting scope notes between jump table and its label. */
530 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
531 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
534 this_block = insn_scope (insn);
535 /* For sequences compute scope resulting from merging all scopes
536 of instructions nested inside. */
537 if (GET_CODE (PATTERN (insn)) == SEQUENCE)
540 rtx body = PATTERN (insn);
543 for (i = 0; i < XVECLEN (body, 0); i++)
544 this_block = choose_inner_scope (this_block,
545 insn_scope (XVECEXP (body, 0, i)));
550 if (this_block != cur_block)
552 change_scope (insn, cur_block, this_block);
553 cur_block = this_block;
557 /* change_scope emits before the insn, not after. */
558 note = emit_note (NOTE_INSN_DELETED);
559 change_scope (note, cur_block, DECL_INITIAL (cfun->decl));
565 /* Given a reorder chain, rearrange the code to match. */
568 fixup_reorder_chain (void)
570 basic_block bb, prev_bb;
574 if (cfg_layout_function_header)
576 set_first_insn (cfg_layout_function_header);
577 insn = cfg_layout_function_header;
578 while (NEXT_INSN (insn))
579 insn = NEXT_INSN (insn);
582 /* First do the bulk reordering -- rechain the blocks without regard to
583 the needed changes to jumps and labels. */
585 for (bb = ENTRY_BLOCK_PTR->next_bb, index = 0;
587 bb = bb->aux, index++)
589 if (bb->il.rtl->header)
592 NEXT_INSN (insn) = bb->il.rtl->header;
594 set_first_insn (bb->il.rtl->header);
595 PREV_INSN (bb->il.rtl->header) = insn;
596 insn = bb->il.rtl->header;
597 while (NEXT_INSN (insn))
598 insn = NEXT_INSN (insn);
601 NEXT_INSN (insn) = BB_HEAD (bb);
603 set_first_insn (BB_HEAD (bb));
604 PREV_INSN (BB_HEAD (bb)) = insn;
606 if (bb->il.rtl->footer)
608 NEXT_INSN (insn) = bb->il.rtl->footer;
609 PREV_INSN (bb->il.rtl->footer) = insn;
610 while (NEXT_INSN (insn))
611 insn = NEXT_INSN (insn);
615 gcc_assert (index == n_basic_blocks);
617 NEXT_INSN (insn) = cfg_layout_function_footer;
618 if (cfg_layout_function_footer)
619 PREV_INSN (cfg_layout_function_footer) = insn;
621 while (NEXT_INSN (insn))
622 insn = NEXT_INSN (insn);
624 set_last_insn (insn);
625 #ifdef ENABLE_CHECKING
626 verify_insn_chain ();
628 delete_dead_jumptables ();
630 /* Now add jumps and labels as needed to match the blocks new
633 for (bb = ENTRY_BLOCK_PTR->next_bb; bb ; bb = bb->aux)
635 edge e_fall, e_taken, e;
640 if (EDGE_COUNT (bb->succs) == 0)
643 /* Find the old fallthru edge, and another non-EH edge for
645 e_taken = e_fall = NULL;
647 FOR_EACH_EDGE (e, ei, bb->succs)
648 if (e->flags & EDGE_FALLTHRU)
650 else if (! (e->flags & EDGE_EH))
653 bb_end_insn = BB_END (bb);
654 if (JUMP_P (bb_end_insn))
656 if (any_condjump_p (bb_end_insn))
658 /* If the old fallthru is still next, nothing to do. */
659 if (bb->aux == e_fall->dest
660 || e_fall->dest == EXIT_BLOCK_PTR)
663 /* The degenerated case of conditional jump jumping to the next
664 instruction can happen on target having jumps with side
667 Create temporarily the duplicated edge representing branch.
668 It will get unidentified by force_nonfallthru_and_redirect
669 that would otherwise get confused by fallthru edge not pointing
670 to the next basic block. */
677 e_fake = unchecked_make_edge (bb, e_fall->dest, 0);
679 redirected = redirect_jump (BB_END (bb),
680 block_label (bb), 0);
681 gcc_assert (redirected);
683 note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX);
686 int prob = INTVAL (XEXP (note, 0));
688 e_fake->probability = prob;
689 e_fake->count = e_fall->count * prob / REG_BR_PROB_BASE;
690 e_fall->probability -= e_fall->probability;
691 e_fall->count -= e_fake->count;
692 if (e_fall->probability < 0)
693 e_fall->probability = 0;
694 if (e_fall->count < 0)
698 /* There is one special case: if *neither* block is next,
699 such as happens at the very end of a function, then we'll
700 need to add a new unconditional jump. Choose the taken
701 edge based on known or assumed probability. */
702 else if (bb->aux != e_taken->dest)
704 rtx note = find_reg_note (bb_end_insn, REG_BR_PROB, 0);
707 && INTVAL (XEXP (note, 0)) < REG_BR_PROB_BASE / 2
708 && invert_jump (bb_end_insn,
709 (e_fall->dest == EXIT_BLOCK_PTR
711 : label_for_bb (e_fall->dest)), 0))
713 e_fall->flags &= ~EDGE_FALLTHRU;
714 #ifdef ENABLE_CHECKING
715 gcc_assert (could_fall_through
716 (e_taken->src, e_taken->dest));
718 e_taken->flags |= EDGE_FALLTHRU;
719 update_br_prob_note (bb);
720 e = e_fall, e_fall = e_taken, e_taken = e;
724 /* If the "jumping" edge is a crossing edge, and the fall
725 through edge is non-crossing, leave things as they are. */
726 else if ((e_taken->flags & EDGE_CROSSING)
727 && !(e_fall->flags & EDGE_CROSSING))
730 /* Otherwise we can try to invert the jump. This will
731 basically never fail, however, keep up the pretense. */
732 else if (invert_jump (bb_end_insn,
733 (e_fall->dest == EXIT_BLOCK_PTR
735 : label_for_bb (e_fall->dest)), 0))
737 e_fall->flags &= ~EDGE_FALLTHRU;
738 #ifdef ENABLE_CHECKING
739 gcc_assert (could_fall_through
740 (e_taken->src, e_taken->dest));
742 e_taken->flags |= EDGE_FALLTHRU;
743 update_br_prob_note (bb);
749 /* Otherwise we have some return, switch or computed
750 jump. In the 99% case, there should not have been a
752 gcc_assert (returnjump_p (bb_end_insn) || !e_fall);
758 /* No fallthru implies a noreturn function with EH edges, or
759 something similarly bizarre. In any case, we don't need to
764 /* If the fallthru block is still next, nothing to do. */
765 if (bb->aux == e_fall->dest)
768 /* A fallthru to exit block. */
769 if (e_fall->dest == EXIT_BLOCK_PTR)
773 /* We got here if we need to add a new jump insn. */
774 nb = force_nonfallthru (e_fall);
777 nb->il.rtl->visited = 1;
780 /* Don't process this new block. */
783 /* Make sure new bb is tagged for correct section (same as
784 fall-thru source, since you cannot fall-throu across
785 section boundaries). */
786 BB_COPY_PARTITION (e_fall->src, single_pred (bb));
787 if (flag_reorder_blocks_and_partition
788 && targetm.have_named_sections
789 && JUMP_P (BB_END (bb))
790 && !any_condjump_p (BB_END (bb))
791 && (EDGE_SUCC (bb, 0)->flags & EDGE_CROSSING))
792 REG_NOTES (BB_END (bb)) = gen_rtx_EXPR_LIST
793 (REG_CROSSING_JUMP, NULL_RTX, REG_NOTES (BB_END (bb)));
797 /* Put basic_block_info in the new order. */
801 fprintf (dump_file, "Reordered sequence:\n");
802 for (bb = ENTRY_BLOCK_PTR->next_bb, index = 0;
804 bb = bb->aux, index++)
806 fprintf (dump_file, " %i ", index);
807 if (get_bb_original (bb))
808 fprintf (dump_file, "duplicate of %i ",
809 get_bb_original (bb)->index);
810 else if (forwarder_block_p (bb)
811 && !LABEL_P (BB_HEAD (bb)))
812 fprintf (dump_file, "compensation ");
814 fprintf (dump_file, "bb %i ", bb->index);
815 fprintf (dump_file, " [%i]\n", bb->frequency);
819 prev_bb = ENTRY_BLOCK_PTR;
820 bb = ENTRY_BLOCK_PTR->next_bb;
823 for (; bb; prev_bb = bb, bb = bb->aux, index ++)
826 BASIC_BLOCK (index) = bb;
828 bb->prev_bb = prev_bb;
829 prev_bb->next_bb = bb;
831 prev_bb->next_bb = EXIT_BLOCK_PTR;
832 EXIT_BLOCK_PTR->prev_bb = prev_bb;
834 /* Annoying special case - jump around dead jumptables left in the code. */
840 FOR_EACH_EDGE (e, ei, bb->succs)
841 if (e->flags & EDGE_FALLTHRU)
844 if (e && !can_fallthru (e->src, e->dest))
845 force_nonfallthru (e);
849 /* Perform sanity checks on the insn chain.
850 1. Check that next/prev pointers are consistent in both the forward and
852 2. Count insns in chain, going both directions, and check if equal.
853 3. Check that get_last_insn () returns the actual end of chain. */
856 verify_insn_chain (void)
859 int insn_cnt1, insn_cnt2;
861 for (prevx = NULL, insn_cnt1 = 1, x = get_insns ();
863 prevx = x, insn_cnt1++, x = NEXT_INSN (x))
864 gcc_assert (PREV_INSN (x) == prevx);
866 gcc_assert (prevx == get_last_insn ());
868 for (nextx = NULL, insn_cnt2 = 1, x = get_last_insn ();
870 nextx = x, insn_cnt2++, x = PREV_INSN (x))
871 gcc_assert (NEXT_INSN (x) == nextx);
873 gcc_assert (insn_cnt1 == insn_cnt2);
876 /* If we have assembler epilogues, the block falling through to exit must
877 be the last one in the reordered chain when we reach final. Ensure
878 that this condition is met. */
880 fixup_fallthru_exit_predecessor (void)
884 basic_block bb = NULL;
886 /* This transformation is not valid before reload, because we might
887 separate a call from the instruction that copies the return
889 gcc_assert (reload_completed);
891 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
892 if (e->flags & EDGE_FALLTHRU)
897 basic_block c = ENTRY_BLOCK_PTR->next_bb;
899 /* If the very first block is the one with the fall-through exit
900 edge, we have to split that block. */
903 bb = split_block (bb, NULL)->dest;
906 bb->il.rtl->footer = c->il.rtl->footer;
907 c->il.rtl->footer = NULL;
922 /* Return true in case it is possible to duplicate the basic block BB. */
924 /* We do not want to declare the function in a header file, since it should
925 only be used through the cfghooks interface, and we do not want to move
926 it to cfgrtl.c since it would require also moving quite a lot of related
928 extern bool cfg_layout_can_duplicate_bb_p (basic_block);
931 cfg_layout_can_duplicate_bb_p (basic_block bb)
933 /* Do not attempt to duplicate tablejumps, as we need to unshare
934 the dispatch table. This is difficult to do, as the instructions
935 computing jump destination may be hoisted outside the basic block. */
936 if (tablejump_p (BB_END (bb), NULL, NULL))
939 /* Do not duplicate blocks containing insns that can't be copied. */
940 if (targetm.cannot_copy_insn_p)
942 rtx insn = BB_HEAD (bb);
945 if (INSN_P (insn) && targetm.cannot_copy_insn_p (insn))
947 if (insn == BB_END (bb))
949 insn = NEXT_INSN (insn);
957 duplicate_insn_chain (rtx from, rtx to)
961 /* Avoid updating of boundaries of previous basic block. The
962 note will get removed from insn stream in fixup. */
963 last = emit_note (NOTE_INSN_DELETED);
965 /* Create copy at the end of INSN chain. The chain will
966 be reordered later. */
967 for (insn = from; insn != NEXT_INSN (to); insn = NEXT_INSN (insn))
969 switch (GET_CODE (insn))
974 /* Avoid copying of dispatch tables. We never duplicate
975 tablejumps, so this can hit only in case the table got
976 moved far from original jump. */
977 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
978 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
980 emit_copy_of_insn_after (insn, get_last_insn ());
991 switch (NOTE_LINE_NUMBER (insn))
993 /* In case prologue is empty and function contain label
994 in first BB, we may want to copy the block. */
995 case NOTE_INSN_PROLOGUE_END:
997 case NOTE_INSN_LOOP_BEG:
998 case NOTE_INSN_LOOP_END:
999 /* Strip down the loop notes - we don't really want to keep
1000 them consistent in loop copies. */
1001 case NOTE_INSN_DELETED:
1002 case NOTE_INSN_DELETED_LABEL:
1003 /* No problem to strip these. */
1004 case NOTE_INSN_EPILOGUE_BEG:
1005 case NOTE_INSN_FUNCTION_END:
1006 /* Debug code expect these notes to exist just once.
1007 Keep them in the master copy.
1008 ??? It probably makes more sense to duplicate them for each
1010 case NOTE_INSN_FUNCTION_BEG:
1011 /* There is always just single entry to function. */
1012 case NOTE_INSN_BASIC_BLOCK:
1015 case NOTE_INSN_REPEATED_LINE_NUMBER:
1016 case NOTE_INSN_SWITCH_TEXT_SECTIONS:
1017 emit_note_copy (insn);
1021 /* All other notes should have already been eliminated.
1023 gcc_assert (NOTE_LINE_NUMBER (insn) >= 0);
1025 /* It is possible that no_line_number is set and the note
1026 won't be emitted. */
1027 emit_note_copy (insn);
1034 insn = NEXT_INSN (last);
1038 /* Create a duplicate of the basic block BB. */
1040 /* We do not want to declare the function in a header file, since it should
1041 only be used through the cfghooks interface, and we do not want to move
1042 it to cfgrtl.c since it would require also moving quite a lot of related
1044 extern basic_block cfg_layout_duplicate_bb (basic_block);
1047 cfg_layout_duplicate_bb (basic_block bb)
1052 insn = duplicate_insn_chain (BB_HEAD (bb), BB_END (bb));
1053 new_bb = create_basic_block (insn,
1054 insn ? get_last_insn () : NULL,
1055 EXIT_BLOCK_PTR->prev_bb);
1057 BB_COPY_PARTITION (new_bb, bb);
1058 if (bb->il.rtl->header)
1060 insn = bb->il.rtl->header;
1061 while (NEXT_INSN (insn))
1062 insn = NEXT_INSN (insn);
1063 insn = duplicate_insn_chain (bb->il.rtl->header, insn);
1065 new_bb->il.rtl->header = unlink_insn_chain (insn, get_last_insn ());
1068 if (bb->il.rtl->footer)
1070 insn = bb->il.rtl->footer;
1071 while (NEXT_INSN (insn))
1072 insn = NEXT_INSN (insn);
1073 insn = duplicate_insn_chain (bb->il.rtl->footer, insn);
1075 new_bb->il.rtl->footer = unlink_insn_chain (insn, get_last_insn ());
1078 if (bb->il.rtl->global_live_at_start)
1080 new_bb->il.rtl->global_live_at_start = ALLOC_REG_SET (®_obstack);
1081 new_bb->il.rtl->global_live_at_end = ALLOC_REG_SET (®_obstack);
1082 COPY_REG_SET (new_bb->il.rtl->global_live_at_start,
1083 bb->il.rtl->global_live_at_start);
1084 COPY_REG_SET (new_bb->il.rtl->global_live_at_end,
1085 bb->il.rtl->global_live_at_end);
1091 /* Main entry point to this module - initialize the datastructures for
1092 CFG layout changes. It keeps LOOPS up-to-date if not null.
1094 FLAGS is a set of additional flags to pass to cleanup_cfg(). It should
1095 include CLEANUP_UPDATE_LIFE if liveness information must be kept up
1099 cfg_layout_initialize (unsigned int flags)
1101 initialize_original_copy_tables ();
1103 cfg_layout_rtl_register_cfg_hooks ();
1105 record_effective_endpoints ();
1107 cleanup_cfg (CLEANUP_CFGLAYOUT | flags);
1110 /* Splits superblocks. */
1112 break_superblocks (void)
1114 sbitmap superblocks;
1118 superblocks = sbitmap_alloc (last_basic_block);
1119 sbitmap_zero (superblocks);
1122 if (bb->flags & BB_SUPERBLOCK)
1124 bb->flags &= ~BB_SUPERBLOCK;
1125 SET_BIT (superblocks, bb->index);
1131 rebuild_jump_labels (get_insns ());
1132 find_many_sub_basic_blocks (superblocks);
1138 /* Finalize the changes: reorder insn list according to the sequence specified
1139 by aux pointers, enter compensation code, rebuild scope forest. */
1142 cfg_layout_finalize (void)
1146 #ifdef ENABLE_CHECKING
1147 verify_flow_info ();
1149 rtl_register_cfg_hooks ();
1150 if (reload_completed
1151 #ifdef HAVE_epilogue
1155 fixup_fallthru_exit_predecessor ();
1156 fixup_reorder_chain ();
1158 #ifdef ENABLE_CHECKING
1159 verify_insn_chain ();
1161 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
1163 bb->il.rtl->header = bb->il.rtl->footer = NULL;
1165 bb->il.rtl->visited = 0;
1168 break_superblocks ();
1170 #ifdef ENABLE_CHECKING
1171 verify_flow_info ();
1174 free_original_copy_tables ();
1177 /* Checks whether all N blocks in BBS array can be copied. */
1179 can_copy_bbs_p (basic_block *bbs, unsigned n)
1185 for (i = 0; i < n; i++)
1186 bbs[i]->flags |= BB_DUPLICATED;
1188 for (i = 0; i < n; i++)
1190 /* In case we should redirect abnormal edge during duplication, fail. */
1192 FOR_EACH_EDGE (e, ei, bbs[i]->succs)
1193 if ((e->flags & EDGE_ABNORMAL)
1194 && (e->dest->flags & BB_DUPLICATED))
1200 if (!can_duplicate_block_p (bbs[i]))
1208 for (i = 0; i < n; i++)
1209 bbs[i]->flags &= ~BB_DUPLICATED;
1214 /* Duplicates N basic blocks stored in array BBS. Newly created basic blocks
1215 are placed into array NEW_BBS in the same order. Edges from basic blocks
1216 in BBS are also duplicated and copies of those of them
1217 that lead into BBS are redirected to appropriate newly created block. The
1218 function assigns bbs into loops (copy of basic block bb is assigned to
1219 bb->loop_father->copy loop, so this must be set up correctly in advance)
1220 and updates dominators locally (LOOPS structure that contains the information
1221 about dominators is passed to enable this).
1223 BASE is the superloop to that basic block belongs; if its header or latch
1224 is copied, we do not set the new blocks as header or latch.
1226 Created copies of N_EDGES edges in array EDGES are stored in array NEW_EDGES,
1227 also in the same order. */
1230 copy_bbs (basic_block *bbs, unsigned n, basic_block *new_bbs,
1231 edge *edges, unsigned num_edges, edge *new_edges,
1235 basic_block bb, new_bb, dom_bb;
1238 /* Duplicate bbs, update dominators, assign bbs to loops. */
1239 for (i = 0; i < n; i++)
1243 new_bb = new_bbs[i] = duplicate_block (bb, NULL);
1244 bb->flags |= BB_DUPLICATED;
1246 add_bb_to_loop (new_bb, bb->loop_father->copy);
1247 /* Possibly set header. */
1248 if (bb->loop_father->header == bb && bb->loop_father != base)
1249 new_bb->loop_father->header = new_bb;
1251 if (bb->loop_father->latch == bb && bb->loop_father != base)
1252 new_bb->loop_father->latch = new_bb;
1255 /* Set dominators. */
1256 for (i = 0; i < n; i++)
1259 new_bb = new_bbs[i];
1261 dom_bb = get_immediate_dominator (CDI_DOMINATORS, bb);
1262 if (dom_bb->flags & BB_DUPLICATED)
1264 dom_bb = get_bb_copy (dom_bb);
1265 set_immediate_dominator (CDI_DOMINATORS, new_bb, dom_bb);
1269 /* Redirect edges. */
1270 for (j = 0; j < num_edges; j++)
1271 new_edges[j] = NULL;
1272 for (i = 0; i < n; i++)
1275 new_bb = new_bbs[i];
1278 FOR_EACH_EDGE (e, ei, new_bb->succs)
1280 for (j = 0; j < num_edges; j++)
1281 if (edges[j] && edges[j]->src == bb && edges[j]->dest == e->dest)
1284 if (!(e->dest->flags & BB_DUPLICATED))
1286 redirect_edge_and_branch_force (e, get_bb_copy (e->dest));
1290 /* Clear information about duplicates. */
1291 for (i = 0; i < n; i++)
1292 bbs[i]->flags &= ~BB_DUPLICATED;
1295 #include "gt-cfglayout.h"