1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
23 /* This file contains the data flow analysis pass of the compiler. It
24 computes data flow information which tells combine_instructions
25 which insns to consider combining and controls register allocation.
27 Additional data flow information that is too bulky to record is
28 generated during the analysis, and is used at that time to create
29 autoincrement and autodecrement addressing.
31 The first step is dividing the function into basic blocks.
32 find_basic_blocks does this. Then life_analysis determines
33 where each register is live and where it is dead.
35 ** find_basic_blocks **
37 find_basic_blocks divides the current function's rtl into basic
38 blocks and constructs the CFG. The blocks are recorded in the
39 basic_block_info array; the CFG exists in the edge structures
40 referenced by the blocks.
42 find_basic_blocks also finds any unreachable loops and deletes them.
46 life_analysis is called immediately after find_basic_blocks.
47 It uses the basic block information to determine where each
48 hard or pseudo register is live.
50 ** live-register info **
52 The information about where each register is live is in two parts:
53 the REG_NOTES of insns, and the vector basic_block->global_live_at_start.
55 basic_block->global_live_at_start has an element for each basic
56 block, and the element is a bit-vector with a bit for each hard or
57 pseudo register. The bit is 1 if the register is live at the
58 beginning of the basic block.
60 Two types of elements can be added to an insn's REG_NOTES.
61 A REG_DEAD note is added to an insn's REG_NOTES for any register
62 that meets both of two conditions: The value in the register is not
63 needed in subsequent insns and the insn does not replace the value in
64 the register (in the case of multi-word hard registers, the value in
65 each register must be replaced by the insn to avoid a REG_DEAD note).
67 In the vast majority of cases, an object in a REG_DEAD note will be
68 used somewhere in the insn. The (rare) exception to this is if an
69 insn uses a multi-word hard register and only some of the registers are
70 needed in subsequent insns. In that case, REG_DEAD notes will be
71 provided for those hard registers that are not subsequently needed.
72 Partial REG_DEAD notes of this type do not occur when an insn sets
73 only some of the hard registers used in such a multi-word operand;
74 omitting REG_DEAD notes for objects stored in an insn is optional and
75 the desire to do so does not justify the complexity of the partial
78 REG_UNUSED notes are added for each register that is set by the insn
79 but is unused subsequently (if every register set by the insn is unused
80 and the insn does not reference memory or have some other side-effect,
81 the insn is deleted instead). If only part of a multi-word hard
82 register is used in a subsequent insn, REG_UNUSED notes are made for
83 the parts that will not be used.
85 To determine which registers are live after any insn, one can
86 start from the beginning of the basic block and scan insns, noting
87 which registers are set by each insn and which die there.
89 ** Other actions of life_analysis **
91 life_analysis sets up the LOG_LINKS fields of insns because the
92 information needed to do so is readily available.
94 life_analysis deletes insns whose only effect is to store a value
97 life_analysis notices cases where a reference to a register as
98 a memory address can be combined with a preceding or following
99 incrementation or decrementation of the register. The separate
100 instruction to increment or decrement is deleted and the address
101 is changed to a POST_INC or similar rtx.
103 Each time an incrementing or decrementing address is created,
104 a REG_INC element is added to the insn's REG_NOTES list.
106 life_analysis fills in certain vectors containing information about
107 register usage: REG_N_REFS, REG_N_DEATHS, REG_N_SETS, REG_LIVE_LENGTH,
108 REG_N_CALLS_CROSSED and REG_BASIC_BLOCK.
110 life_analysis sets current_function_sp_is_unchanging if the function
111 doesn't modify the stack pointer. */
115 Split out from life_analysis:
116 - local property discovery (bb->local_live, bb->local_set)
117 - global property computation
119 - pre/post modify transformation
127 #include "hard-reg-set.h"
128 #include "basic-block.h"
129 #include "insn-config.h"
133 #include "function.h"
137 #include "insn-flags.h"
141 #include "splay-tree.h"
143 #define obstack_chunk_alloc xmalloc
144 #define obstack_chunk_free free
147 /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
148 the stack pointer does not matter. The value is tested only in
149 functions that have frame pointers.
150 No definition is equivalent to always zero. */
151 #ifndef EXIT_IGNORE_STACK
152 #define EXIT_IGNORE_STACK 0
155 #ifndef HAVE_epilogue
156 #define HAVE_epilogue 0
158 #ifndef HAVE_prologue
159 #define HAVE_prologue 0
161 #ifndef HAVE_sibcall_epilogue
162 #define HAVE_sibcall_epilogue 0
165 /* The contents of the current function definition are allocated
166 in this obstack, and all are freed at the end of the function.
167 For top-level functions, this is temporary_obstack.
168 Separate obstacks are made for nested functions. */
170 extern struct obstack *function_obstack;
172 /* Number of basic blocks in the current function. */
176 /* Number of edges in the current function. */
180 /* The basic block array. */
182 varray_type basic_block_info;
184 /* The special entry and exit blocks. */
186 struct basic_block_def entry_exit_blocks[2]
191 NULL, /* local_set */
192 NULL, /* global_live_at_start */
193 NULL, /* global_live_at_end */
195 ENTRY_BLOCK, /* index */
197 -1, -1, /* eh_beg, eh_end */
205 NULL, /* local_set */
206 NULL, /* global_live_at_start */
207 NULL, /* global_live_at_end */
209 EXIT_BLOCK, /* index */
211 -1, -1, /* eh_beg, eh_end */
216 /* Nonzero if the second flow pass has completed. */
219 /* Maximum register number used in this function, plus one. */
223 /* Indexed by n, giving various register information */
225 varray_type reg_n_info;
227 /* Size of a regset for the current function,
228 in (1) bytes and (2) elements. */
233 /* Regset of regs live when calls to `setjmp'-like functions happen. */
234 /* ??? Does this exist only for the setjmp-clobbered warning message? */
236 regset regs_live_at_setjmp;
238 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
239 that have to go in the same hard reg.
240 The first two regs in the list are a pair, and the next two
241 are another pair, etc. */
244 /* Set of registers that may be eliminable. These are handled specially
245 in updating regs_ever_live. */
247 static HARD_REG_SET elim_reg_set;
249 /* The basic block structure for every insn, indexed by uid. */
251 varray_type basic_block_for_insn;
253 /* The labels mentioned in non-jump rtl. Valid during find_basic_blocks. */
254 /* ??? Should probably be using LABEL_NUSES instead. It would take a
255 bit of surgery to be able to use or co-opt the routines in jump. */
257 static rtx label_value_list;
258 static rtx tail_recursion_label_list;
260 /* Holds information for tracking conditional register life information. */
261 struct reg_cond_life_info
263 /* An EXPR_LIST of conditions under which a register is dead. */
266 /* ??? Could store mask of bytes that are dead, so that we could finally
267 track lifetimes of multi-word registers accessed via subregs. */
270 /* For use in communicating between propagate_block and its subroutines.
271 Holds all information needed to compute life and def-use information. */
273 struct propagate_block_info
275 /* The basic block we're considering. */
278 /* Bit N is set if register N is conditionally or unconditionally live. */
281 /* Bit N is set if register N is set this insn. */
284 /* Element N is the next insn that uses (hard or pseudo) register N
285 within the current basic block; or zero, if there is no such insn. */
288 /* Contains a list of all the MEMs we are tracking for dead store
292 /* If non-null, record the set of registers set in the basic block. */
295 #ifdef HAVE_conditional_execution
296 /* Indexed by register number, holds a reg_cond_life_info for each
297 register that is not unconditionally live or dead. */
298 splay_tree reg_cond_dead;
300 /* Bit N is set if register N is in an expression in reg_cond_dead. */
304 /* Non-zero if the value of CC0 is live. */
307 /* Flags controling the set of information propagate_block collects. */
311 /* Forward declarations */
312 static int count_basic_blocks PARAMS ((rtx));
313 static void find_basic_blocks_1 PARAMS ((rtx));
314 static rtx find_label_refs PARAMS ((rtx, rtx));
315 static void clear_edges PARAMS ((void));
316 static void make_edges PARAMS ((rtx));
317 static void make_label_edge PARAMS ((sbitmap *, basic_block,
319 static void make_eh_edge PARAMS ((sbitmap *, eh_nesting_info *,
320 basic_block, rtx, int));
321 static void mark_critical_edges PARAMS ((void));
322 static void move_stray_eh_region_notes PARAMS ((void));
323 static void record_active_eh_regions PARAMS ((rtx));
325 static void commit_one_edge_insertion PARAMS ((edge));
327 static void delete_unreachable_blocks PARAMS ((void));
328 static void delete_eh_regions PARAMS ((void));
329 static int can_delete_note_p PARAMS ((rtx));
330 static void expunge_block PARAMS ((basic_block));
331 static int can_delete_label_p PARAMS ((rtx));
332 static int tail_recursion_label_p PARAMS ((rtx));
333 static int merge_blocks_move_predecessor_nojumps PARAMS ((basic_block,
335 static int merge_blocks_move_successor_nojumps PARAMS ((basic_block,
337 static int merge_blocks PARAMS ((edge,basic_block,basic_block));
338 static void try_merge_blocks PARAMS ((void));
339 static void tidy_fallthru_edges PARAMS ((void));
340 static int verify_wide_reg_1 PARAMS ((rtx *, void *));
341 static void verify_wide_reg PARAMS ((int, rtx, rtx));
342 static void verify_local_live_at_start PARAMS ((regset, basic_block));
343 static int set_noop_p PARAMS ((rtx));
344 static int noop_move_p PARAMS ((rtx));
345 static void delete_noop_moves PARAMS ((rtx));
346 static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
347 static void notice_stack_pointer_modification PARAMS ((rtx));
348 static void mark_reg PARAMS ((rtx, void *));
349 static void mark_regs_live_at_end PARAMS ((regset));
350 static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
351 static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
352 static void propagate_block_delete_insn PARAMS ((basic_block, rtx));
353 static rtx propagate_block_delete_libcall PARAMS ((basic_block, rtx, rtx));
354 static int insn_dead_p PARAMS ((struct propagate_block_info *,
356 static int libcall_dead_p PARAMS ((struct propagate_block_info *,
358 static void mark_set_regs PARAMS ((struct propagate_block_info *,
360 static void mark_set_1 PARAMS ((struct propagate_block_info *,
361 enum rtx_code, rtx, rtx,
363 #ifdef HAVE_conditional_execution
364 static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
366 static void free_reg_cond_life_info PARAMS ((splay_tree_value));
367 static int flush_reg_cond_reg_1 PARAMS ((splay_tree_node, void *));
368 static void flush_reg_cond_reg PARAMS ((struct propagate_block_info *,
370 static rtx ior_reg_cond PARAMS ((rtx, rtx));
371 static rtx not_reg_cond PARAMS ((rtx));
372 static rtx nand_reg_cond PARAMS ((rtx, rtx));
375 static void attempt_auto_inc PARAMS ((struct propagate_block_info *,
376 rtx, rtx, rtx, rtx, rtx));
377 static void find_auto_inc PARAMS ((struct propagate_block_info *,
379 static int try_pre_increment_1 PARAMS ((struct propagate_block_info *,
381 static int try_pre_increment PARAMS ((rtx, rtx, HOST_WIDE_INT));
383 static void mark_used_reg PARAMS ((struct propagate_block_info *,
385 static void mark_used_regs PARAMS ((struct propagate_block_info *,
387 void dump_flow_info PARAMS ((FILE *));
388 void debug_flow_info PARAMS ((void));
389 static void dump_edge_info PARAMS ((FILE *, edge, int));
391 static void invalidate_mems_from_autoinc PARAMS ((struct propagate_block_info *,
393 static void remove_fake_successors PARAMS ((basic_block));
394 static void flow_nodes_print PARAMS ((const char *, const sbitmap, FILE *));
395 static void flow_exits_print PARAMS ((const char *, const edge *, int, FILE *));
396 static void flow_loops_cfg_dump PARAMS ((const struct loops *, FILE *));
397 static int flow_loop_nested_p PARAMS ((struct loop *, struct loop *));
398 static int flow_loop_exits_find PARAMS ((const sbitmap, edge **));
399 static int flow_loop_nodes_find PARAMS ((basic_block, basic_block, sbitmap));
400 static int flow_depth_first_order_compute PARAMS ((int *, int *));
401 static basic_block flow_loop_pre_header_find PARAMS ((basic_block, const sbitmap *));
402 static void flow_loop_tree_node_add PARAMS ((struct loop *, struct loop *));
403 static void flow_loops_tree_build PARAMS ((struct loops *));
404 static int flow_loop_level_compute PARAMS ((struct loop *, int));
405 static int flow_loops_level_compute PARAMS ((struct loops *));
407 /* Find basic blocks of the current function.
408 F is the first insn of the function and NREGS the number of register
412 find_basic_blocks (f, nregs, file)
414 int nregs ATTRIBUTE_UNUSED;
415 FILE *file ATTRIBUTE_UNUSED;
419 /* Flush out existing data. */
420 if (basic_block_info != NULL)
426 /* Clear bb->aux on all extant basic blocks. We'll use this as a
427 tag for reuse during create_basic_block, just in case some pass
428 copies around basic block notes improperly. */
429 for (i = 0; i < n_basic_blocks; ++i)
430 BASIC_BLOCK (i)->aux = NULL;
432 VARRAY_FREE (basic_block_info);
435 n_basic_blocks = count_basic_blocks (f);
437 /* Size the basic block table. The actual structures will be allocated
438 by find_basic_blocks_1, since we want to keep the structure pointers
439 stable across calls to find_basic_blocks. */
440 /* ??? This whole issue would be much simpler if we called find_basic_blocks
441 exactly once, and thereafter we don't have a single long chain of
442 instructions at all until close to the end of compilation when we
443 actually lay them out. */
445 VARRAY_BB_INIT (basic_block_info, n_basic_blocks, "basic_block_info");
447 find_basic_blocks_1 (f);
449 /* Record the block to which an insn belongs. */
450 /* ??? This should be done another way, by which (perhaps) a label is
451 tagged directly with the basic block that it starts. It is used for
452 more than that currently, but IMO that is the only valid use. */
454 max_uid = get_max_uid ();
456 /* Leave space for insns life_analysis makes in some cases for auto-inc.
457 These cases are rare, so we don't need too much space. */
458 max_uid += max_uid / 10;
461 compute_bb_for_insn (max_uid);
463 /* Discover the edges of our cfg. */
464 record_active_eh_regions (f);
465 make_edges (label_value_list);
467 /* Do very simple cleanup now, for the benefit of code that runs between
468 here and cleanup_cfg, e.g. thread_prologue_and_epilogue_insns. */
469 tidy_fallthru_edges ();
471 mark_critical_edges ();
473 #ifdef ENABLE_CHECKING
478 /* Count the basic blocks of the function. */
481 count_basic_blocks (f)
485 register RTX_CODE prev_code;
486 register int count = 0;
488 int call_had_abnormal_edge = 0;
490 prev_code = JUMP_INSN;
491 for (insn = f; insn; insn = NEXT_INSN (insn))
493 register RTX_CODE code = GET_CODE (insn);
495 if (code == CODE_LABEL
496 || (GET_RTX_CLASS (code) == 'i'
497 && (prev_code == JUMP_INSN
498 || prev_code == BARRIER
499 || (prev_code == CALL_INSN && call_had_abnormal_edge))))
502 /* Record whether this call created an edge. */
503 if (code == CALL_INSN)
505 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
506 int region = (note ? INTVAL (XEXP (note, 0)) : 1);
508 call_had_abnormal_edge = 0;
510 /* If there is an EH region or rethrow, we have an edge. */
511 if ((eh_region && region > 0)
512 || find_reg_note (insn, REG_EH_RETHROW, NULL_RTX))
513 call_had_abnormal_edge = 1;
514 else if (nonlocal_goto_handler_labels && region >= 0)
515 /* If there is a nonlocal goto label and the specified
516 region number isn't -1, we have an edge. (0 means
517 no throw, but might have a nonlocal goto). */
518 call_had_abnormal_edge = 1;
523 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
525 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
529 /* The rest of the compiler works a bit smoother when we don't have to
530 check for the edge case of do-nothing functions with no basic blocks. */
533 emit_insn (gen_rtx_USE (VOIDmode, const0_rtx));
540 /* Scan a list of insns for labels referred to other than by jumps.
541 This is used to scan the alternatives of a call placeholder. */
543 find_label_refs (f, lvl)
549 for (insn = f; insn; insn = NEXT_INSN (insn))
550 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
554 /* Make a list of all labels referred to other than by jumps
555 (which just don't have the REG_LABEL notes).
557 Make a special exception for labels followed by an ADDR*VEC,
558 as this would be a part of the tablejump setup code.
560 Make a special exception for the eh_return_stub_label, which
561 we know isn't part of any otherwise visible control flow. */
563 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
564 if (REG_NOTE_KIND (note) == REG_LABEL)
566 rtx lab = XEXP (note, 0), next;
568 if (lab == eh_return_stub_label)
570 else if ((next = next_nonnote_insn (lab)) != NULL
571 && GET_CODE (next) == JUMP_INSN
572 && (GET_CODE (PATTERN (next)) == ADDR_VEC
573 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
575 else if (GET_CODE (lab) == NOTE)
578 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
585 /* Find all basic blocks of the function whose first insn is F.
587 Collect and return a list of labels whose addresses are taken. This
588 will be used in make_edges for use with computed gotos. */
591 find_basic_blocks_1 (f)
594 register rtx insn, next;
596 rtx bb_note = NULL_RTX;
597 rtx eh_list = NULL_RTX;
603 /* We process the instructions in a slightly different way than we did
604 previously. This is so that we see a NOTE_BASIC_BLOCK after we have
605 closed out the previous block, so that it gets attached at the proper
606 place. Since this form should be equivalent to the previous,
607 count_basic_blocks continues to use the old form as a check. */
609 for (insn = f; insn; insn = next)
611 enum rtx_code code = GET_CODE (insn);
613 next = NEXT_INSN (insn);
619 int kind = NOTE_LINE_NUMBER (insn);
621 /* Keep a LIFO list of the currently active exception notes. */
622 if (kind == NOTE_INSN_EH_REGION_BEG)
623 eh_list = alloc_INSN_LIST (insn, eh_list);
624 else if (kind == NOTE_INSN_EH_REGION_END)
628 eh_list = XEXP (eh_list, 1);
629 free_INSN_LIST_node (t);
632 /* Look for basic block notes with which to keep the
633 basic_block_info pointers stable. Unthread the note now;
634 we'll put it back at the right place in create_basic_block.
635 Or not at all if we've already found a note in this block. */
636 else if (kind == NOTE_INSN_BASIC_BLOCK)
638 if (bb_note == NULL_RTX)
641 next = flow_delete_insn (insn);
647 /* A basic block starts at a label. If we've closed one off due
648 to a barrier or some such, no need to do it again. */
649 if (head != NULL_RTX)
651 /* While we now have edge lists with which other portions of
652 the compiler might determine a call ending a basic block
653 does not imply an abnormal edge, it will be a bit before
654 everything can be updated. So continue to emit a noop at
655 the end of such a block. */
656 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
658 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
659 end = emit_insn_after (nop, end);
662 create_basic_block (i++, head, end, bb_note);
670 /* A basic block ends at a jump. */
671 if (head == NULL_RTX)
675 /* ??? Make a special check for table jumps. The way this
676 happens is truly and amazingly gross. We are about to
677 create a basic block that contains just a code label and
678 an addr*vec jump insn. Worse, an addr_diff_vec creates
679 its own natural loop.
681 Prevent this bit of brain damage, pasting things together
682 correctly in make_edges.
684 The correct solution involves emitting the table directly
685 on the tablejump instruction as a note, or JUMP_LABEL. */
687 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
688 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
696 goto new_bb_inclusive;
699 /* A basic block ends at a barrier. It may be that an unconditional
700 jump already closed the basic block -- no need to do it again. */
701 if (head == NULL_RTX)
704 /* While we now have edge lists with which other portions of the
705 compiler might determine a call ending a basic block does not
706 imply an abnormal edge, it will be a bit before everything can
707 be updated. So continue to emit a noop at the end of such a
709 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
711 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
712 end = emit_insn_after (nop, end);
714 goto new_bb_exclusive;
718 /* Record whether this call created an edge. */
719 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
720 int region = (note ? INTVAL (XEXP (note, 0)) : 1);
721 int call_has_abnormal_edge = 0;
723 if (GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
725 /* Scan each of the alternatives for label refs. */
726 lvl = find_label_refs (XEXP (PATTERN (insn), 0), lvl);
727 lvl = find_label_refs (XEXP (PATTERN (insn), 1), lvl);
728 lvl = find_label_refs (XEXP (PATTERN (insn), 2), lvl);
729 /* Record its tail recursion label, if any. */
730 if (XEXP (PATTERN (insn), 3) != NULL_RTX)
731 trll = alloc_EXPR_LIST (0, XEXP (PATTERN (insn), 3), trll);
734 /* If there is an EH region or rethrow, we have an edge. */
735 if ((eh_list && region > 0)
736 || find_reg_note (insn, REG_EH_RETHROW, NULL_RTX))
737 call_has_abnormal_edge = 1;
738 else if (nonlocal_goto_handler_labels && region >= 0)
739 /* If there is a nonlocal goto label and the specified
740 region number isn't -1, we have an edge. (0 means
741 no throw, but might have a nonlocal goto). */
742 call_has_abnormal_edge = 1;
744 /* A basic block ends at a call that can either throw or
745 do a non-local goto. */
746 if (call_has_abnormal_edge)
749 if (head == NULL_RTX)
754 create_basic_block (i++, head, end, bb_note);
755 head = end = NULL_RTX;
763 if (GET_RTX_CLASS (code) == 'i')
765 if (head == NULL_RTX)
772 if (GET_RTX_CLASS (code) == 'i')
776 /* Make a list of all labels referred to other than by jumps
777 (which just don't have the REG_LABEL notes).
779 Make a special exception for labels followed by an ADDR*VEC,
780 as this would be a part of the tablejump setup code.
782 Make a special exception for the eh_return_stub_label, which
783 we know isn't part of any otherwise visible control flow. */
785 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
786 if (REG_NOTE_KIND (note) == REG_LABEL)
788 rtx lab = XEXP (note, 0), next;
790 if (lab == eh_return_stub_label)
792 else if ((next = next_nonnote_insn (lab)) != NULL
793 && GET_CODE (next) == JUMP_INSN
794 && (GET_CODE (PATTERN (next)) == ADDR_VEC
795 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
797 else if (GET_CODE (lab) == NOTE)
800 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
805 if (head != NULL_RTX)
806 create_basic_block (i++, head, end, bb_note);
808 flow_delete_insn (bb_note);
810 if (i != n_basic_blocks)
813 label_value_list = lvl;
814 tail_recursion_label_list = trll;
817 /* Tidy the CFG by deleting unreachable code and whatnot. */
823 delete_unreachable_blocks ();
824 move_stray_eh_region_notes ();
825 record_active_eh_regions (f);
827 mark_critical_edges ();
829 /* Kill the data we won't maintain. */
830 free_EXPR_LIST_list (&label_value_list);
831 free_EXPR_LIST_list (&tail_recursion_label_list);
834 /* Create a new basic block consisting of the instructions between
835 HEAD and END inclusive. Reuses the note and basic block struct
836 in BB_NOTE, if any. */
839 create_basic_block (index, head, end, bb_note)
841 rtx head, end, bb_note;
846 && ! RTX_INTEGRATED_P (bb_note)
847 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
850 /* If we found an existing note, thread it back onto the chain. */
854 if (GET_CODE (head) == CODE_LABEL)
858 after = PREV_INSN (head);
862 if (after != bb_note && NEXT_INSN (after) != bb_note)
863 reorder_insns (bb_note, bb_note, after);
867 /* Otherwise we must create a note and a basic block structure.
868 Since we allow basic block structs in rtl, give the struct
869 the same lifetime by allocating it off the function obstack
870 rather than using malloc. */
872 bb = (basic_block) obstack_alloc (function_obstack, sizeof (*bb));
873 memset (bb, 0, sizeof (*bb));
875 if (GET_CODE (head) == CODE_LABEL)
876 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
879 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
882 NOTE_BASIC_BLOCK (bb_note) = bb;
885 /* Always include the bb note in the block. */
886 if (NEXT_INSN (end) == bb_note)
892 BASIC_BLOCK (index) = bb;
894 /* Tag the block so that we know it has been used when considering
895 other basic block notes. */
899 /* Records the basic block struct in BB_FOR_INSN, for every instruction
900 indexed by INSN_UID. MAX is the size of the array. */
903 compute_bb_for_insn (max)
908 if (basic_block_for_insn)
909 VARRAY_FREE (basic_block_for_insn);
910 VARRAY_BB_INIT (basic_block_for_insn, max, "basic_block_for_insn");
912 for (i = 0; i < n_basic_blocks; ++i)
914 basic_block bb = BASIC_BLOCK (i);
921 int uid = INSN_UID (insn);
923 VARRAY_BB (basic_block_for_insn, uid) = bb;
926 insn = NEXT_INSN (insn);
931 /* Free the memory associated with the edge structures. */
939 for (i = 0; i < n_basic_blocks; ++i)
941 basic_block bb = BASIC_BLOCK (i);
943 for (e = bb->succ; e ; e = n)
953 for (e = ENTRY_BLOCK_PTR->succ; e ; e = n)
959 ENTRY_BLOCK_PTR->succ = 0;
960 EXIT_BLOCK_PTR->pred = 0;
965 /* Identify the edges between basic blocks.
967 NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks
968 that are otherwise unreachable may be reachable with a non-local goto.
970 BB_EH_END is an array indexed by basic block number in which we record
971 the list of exception regions active at the end of the basic block. */
974 make_edges (label_value_list)
975 rtx label_value_list;
978 eh_nesting_info *eh_nest_info = init_eh_nesting_info ();
979 sbitmap *edge_cache = NULL;
981 /* Assume no computed jump; revise as we create edges. */
982 current_function_has_computed_jump = 0;
984 /* Heavy use of computed goto in machine-generated code can lead to
985 nearly fully-connected CFGs. In that case we spend a significant
986 amount of time searching the edge lists for duplicates. */
987 if (forced_labels || label_value_list)
989 edge_cache = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
990 sbitmap_vector_zero (edge_cache, n_basic_blocks);
993 /* By nature of the way these get numbered, block 0 is always the entry. */
994 make_edge (edge_cache, ENTRY_BLOCK_PTR, BASIC_BLOCK (0), EDGE_FALLTHRU);
996 for (i = 0; i < n_basic_blocks; ++i)
998 basic_block bb = BASIC_BLOCK (i);
1001 int force_fallthru = 0;
1003 /* Examine the last instruction of the block, and discover the
1004 ways we can leave the block. */
1007 code = GET_CODE (insn);
1010 if (code == JUMP_INSN)
1014 /* ??? Recognize a tablejump and do the right thing. */
1015 if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1016 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1017 && GET_CODE (tmp) == JUMP_INSN
1018 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1019 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1024 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1025 vec = XVEC (PATTERN (tmp), 0);
1027 vec = XVEC (PATTERN (tmp), 1);
1029 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1030 make_label_edge (edge_cache, bb,
1031 XEXP (RTVEC_ELT (vec, j), 0), 0);
1033 /* Some targets (eg, ARM) emit a conditional jump that also
1034 contains the out-of-range target. Scan for these and
1035 add an edge if necessary. */
1036 if ((tmp = single_set (insn)) != NULL
1037 && SET_DEST (tmp) == pc_rtx
1038 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1039 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF)
1040 make_label_edge (edge_cache, bb,
1041 XEXP (XEXP (SET_SRC (tmp), 2), 0), 0);
1043 #ifdef CASE_DROPS_THROUGH
1044 /* Silly VAXen. The ADDR_VEC is going to be in the way of
1045 us naturally detecting fallthru into the next block. */
1050 /* If this is a computed jump, then mark it as reaching
1051 everything on the label_value_list and forced_labels list. */
1052 else if (computed_jump_p (insn))
1054 current_function_has_computed_jump = 1;
1056 for (x = label_value_list; x; x = XEXP (x, 1))
1057 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1059 for (x = forced_labels; x; x = XEXP (x, 1))
1060 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1063 /* Returns create an exit out. */
1064 else if (returnjump_p (insn))
1065 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, 0);
1067 /* Otherwise, we have a plain conditional or unconditional jump. */
1070 if (! JUMP_LABEL (insn))
1072 make_label_edge (edge_cache, bb, JUMP_LABEL (insn), 0);
1076 /* If this is a sibling call insn, then this is in effect a
1077 combined call and return, and so we need an edge to the
1078 exit block. No need to worry about EH edges, since we
1079 wouldn't have created the sibling call in the first place. */
1081 if (code == CALL_INSN && SIBLING_CALL_P (insn))
1082 make_edge (edge_cache, bb, EXIT_BLOCK_PTR,
1083 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1086 /* If this is a CALL_INSN, then mark it as reaching the active EH
1087 handler for this CALL_INSN. If we're handling asynchronous
1088 exceptions then any insn can reach any of the active handlers.
1090 Also mark the CALL_INSN as reaching any nonlocal goto handler. */
1092 if (code == CALL_INSN || asynchronous_exceptions)
1094 /* Add any appropriate EH edges. We do this unconditionally
1095 since there may be a REG_EH_REGION or REG_EH_RETHROW note
1096 on the call, and this needn't be within an EH region. */
1097 make_eh_edge (edge_cache, eh_nest_info, bb, insn, bb->eh_end);
1099 /* If we have asynchronous exceptions, do the same for *all*
1100 exception regions active in the block. */
1101 if (asynchronous_exceptions
1102 && bb->eh_beg != bb->eh_end)
1104 if (bb->eh_beg >= 0)
1105 make_eh_edge (edge_cache, eh_nest_info, bb,
1106 NULL_RTX, bb->eh_beg);
1108 for (x = bb->head; x != bb->end; x = NEXT_INSN (x))
1109 if (GET_CODE (x) == NOTE
1110 && (NOTE_LINE_NUMBER (x) == NOTE_INSN_EH_REGION_BEG
1111 || NOTE_LINE_NUMBER (x) == NOTE_INSN_EH_REGION_END))
1113 int region = NOTE_EH_HANDLER (x);
1114 make_eh_edge (edge_cache, eh_nest_info, bb,
1119 if (code == CALL_INSN && nonlocal_goto_handler_labels)
1121 /* ??? This could be made smarter: in some cases it's possible
1122 to tell that certain calls will not do a nonlocal goto.
1124 For example, if the nested functions that do the nonlocal
1125 gotos do not have their addresses taken, then only calls to
1126 those functions or to other nested functions that use them
1127 could possibly do nonlocal gotos. */
1128 /* We do know that a REG_EH_REGION note with a value less
1129 than 0 is guaranteed not to perform a non-local goto. */
1130 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
1131 if (!note || INTVAL (XEXP (note, 0)) >= 0)
1132 for (x = nonlocal_goto_handler_labels; x ; x = XEXP (x, 1))
1133 make_label_edge (edge_cache, bb, XEXP (x, 0),
1134 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1138 /* We know something about the structure of the function __throw in
1139 libgcc2.c. It is the only function that ever contains eh_stub
1140 labels. It modifies its return address so that the last block
1141 returns to one of the eh_stub labels within it. So we have to
1142 make additional edges in the flow graph. */
1143 if (i + 1 == n_basic_blocks && eh_return_stub_label != 0)
1144 make_label_edge (edge_cache, bb, eh_return_stub_label, EDGE_EH);
1146 /* Find out if we can drop through to the next block. */
1147 insn = next_nonnote_insn (insn);
1148 if (!insn || (i + 1 == n_basic_blocks && force_fallthru))
1149 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU);
1150 else if (i + 1 < n_basic_blocks)
1152 rtx tmp = BLOCK_HEAD (i + 1);
1153 if (GET_CODE (tmp) == NOTE)
1154 tmp = next_nonnote_insn (tmp);
1155 if (force_fallthru || insn == tmp)
1156 make_edge (edge_cache, bb, BASIC_BLOCK (i + 1), EDGE_FALLTHRU);
1160 free_eh_nesting_info (eh_nest_info);
1162 sbitmap_vector_free (edge_cache);
1165 /* Create an edge between two basic blocks. FLAGS are auxiliary information
1166 about the edge that is accumulated between calls. */
1169 make_edge (edge_cache, src, dst, flags)
1170 sbitmap *edge_cache;
1171 basic_block src, dst;
1177 /* Don't bother with edge cache for ENTRY or EXIT; there aren't that
1178 many edges to them, and we didn't allocate memory for it. */
1179 use_edge_cache = (edge_cache
1180 && src != ENTRY_BLOCK_PTR
1181 && dst != EXIT_BLOCK_PTR);
1183 /* Make sure we don't add duplicate edges. */
1184 if (! use_edge_cache || TEST_BIT (edge_cache[src->index], dst->index))
1185 for (e = src->succ; e ; e = e->succ_next)
1192 e = (edge) xcalloc (1, sizeof (*e));
1195 e->succ_next = src->succ;
1196 e->pred_next = dst->pred;
1205 SET_BIT (edge_cache[src->index], dst->index);
1208 /* Create an edge from a basic block to a label. */
1211 make_label_edge (edge_cache, src, label, flags)
1212 sbitmap *edge_cache;
1217 if (GET_CODE (label) != CODE_LABEL)
1220 /* If the label was never emitted, this insn is junk, but avoid a
1221 crash trying to refer to BLOCK_FOR_INSN (label). This can happen
1222 as a result of a syntax error and a diagnostic has already been
1225 if (INSN_UID (label) == 0)
1228 make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags);
1231 /* Create the edges generated by INSN in REGION. */
1234 make_eh_edge (edge_cache, eh_nest_info, src, insn, region)
1235 sbitmap *edge_cache;
1236 eh_nesting_info *eh_nest_info;
1241 handler_info **handler_list;
1244 is_call = (insn && GET_CODE (insn) == CALL_INSN ? EDGE_ABNORMAL_CALL : 0);
1245 num = reachable_handlers (region, eh_nest_info, insn, &handler_list);
1248 make_label_edge (edge_cache, src, handler_list[num]->handler_label,
1249 EDGE_ABNORMAL | EDGE_EH | is_call);
1253 /* EH_REGION notes appearing between basic blocks is ambiguous, and even
1254 dangerous if we intend to move basic blocks around. Move such notes
1255 into the following block. */
1258 move_stray_eh_region_notes ()
1263 if (n_basic_blocks < 2)
1266 b2 = BASIC_BLOCK (n_basic_blocks - 1);
1267 for (i = n_basic_blocks - 2; i >= 0; --i, b2 = b1)
1269 rtx insn, next, list = NULL_RTX;
1271 b1 = BASIC_BLOCK (i);
1272 for (insn = NEXT_INSN (b1->end); insn != b2->head; insn = next)
1274 next = NEXT_INSN (insn);
1275 if (GET_CODE (insn) == NOTE
1276 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG
1277 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
1279 /* Unlink from the insn chain. */
1280 NEXT_INSN (PREV_INSN (insn)) = next;
1281 PREV_INSN (next) = PREV_INSN (insn);
1284 NEXT_INSN (insn) = list;
1289 if (list == NULL_RTX)
1292 /* Find where to insert these things. */
1294 if (GET_CODE (insn) == CODE_LABEL)
1295 insn = NEXT_INSN (insn);
1299 next = NEXT_INSN (list);
1300 add_insn_after (list, insn);
1306 /* Recompute eh_beg/eh_end for each basic block. */
1309 record_active_eh_regions (f)
1312 rtx insn, eh_list = NULL_RTX;
1314 basic_block bb = BASIC_BLOCK (0);
1316 for (insn = f; insn ; insn = NEXT_INSN (insn))
1318 if (bb->head == insn)
1319 bb->eh_beg = (eh_list ? NOTE_EH_HANDLER (XEXP (eh_list, 0)) : -1);
1321 if (GET_CODE (insn) == NOTE)
1323 int kind = NOTE_LINE_NUMBER (insn);
1324 if (kind == NOTE_INSN_EH_REGION_BEG)
1325 eh_list = alloc_INSN_LIST (insn, eh_list);
1326 else if (kind == NOTE_INSN_EH_REGION_END)
1328 rtx t = XEXP (eh_list, 1);
1329 free_INSN_LIST_node (eh_list);
1334 if (bb->end == insn)
1336 bb->eh_end = (eh_list ? NOTE_EH_HANDLER (XEXP (eh_list, 0)) : -1);
1338 if (i == n_basic_blocks)
1340 bb = BASIC_BLOCK (i);
1345 /* Identify critical edges and set the bits appropriately. */
1348 mark_critical_edges ()
1350 int i, n = n_basic_blocks;
1353 /* We begin with the entry block. This is not terribly important now,
1354 but could be if a front end (Fortran) implemented alternate entry
1356 bb = ENTRY_BLOCK_PTR;
1363 /* (1) Critical edges must have a source with multiple successors. */
1364 if (bb->succ && bb->succ->succ_next)
1366 for (e = bb->succ; e ; e = e->succ_next)
1368 /* (2) Critical edges must have a destination with multiple
1369 predecessors. Note that we know there is at least one
1370 predecessor -- the edge we followed to get here. */
1371 if (e->dest->pred->pred_next)
1372 e->flags |= EDGE_CRITICAL;
1374 e->flags &= ~EDGE_CRITICAL;
1379 for (e = bb->succ; e ; e = e->succ_next)
1380 e->flags &= ~EDGE_CRITICAL;
1385 bb = BASIC_BLOCK (i);
1389 /* Split a (typically critical) edge. Return the new block.
1390 Abort on abnormal edges.
1392 ??? The code generally expects to be called on critical edges.
1393 The case of a block ending in an unconditional jump to a
1394 block with multiple predecessors is not handled optimally. */
1397 split_edge (edge_in)
1400 basic_block old_pred, bb, old_succ;
1405 /* Abnormal edges cannot be split. */
1406 if ((edge_in->flags & EDGE_ABNORMAL) != 0)
1409 old_pred = edge_in->src;
1410 old_succ = edge_in->dest;
1412 /* Remove the existing edge from the destination's pred list. */
1415 for (pp = &old_succ->pred; *pp != edge_in; pp = &(*pp)->pred_next)
1417 *pp = edge_in->pred_next;
1418 edge_in->pred_next = NULL;
1421 /* Create the new structures. */
1422 bb = (basic_block) obstack_alloc (function_obstack, sizeof (*bb));
1423 edge_out = (edge) xcalloc (1, sizeof (*edge_out));
1426 memset (bb, 0, sizeof (*bb));
1428 /* ??? This info is likely going to be out of date very soon. */
1429 if (old_succ->global_live_at_start)
1431 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (function_obstack);
1432 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (function_obstack);
1433 COPY_REG_SET (bb->global_live_at_start, old_succ->global_live_at_start);
1434 COPY_REG_SET (bb->global_live_at_end, old_succ->global_live_at_start);
1439 bb->succ = edge_out;
1440 bb->count = edge_in->count;
1443 edge_in->flags &= ~EDGE_CRITICAL;
1445 edge_out->pred_next = old_succ->pred;
1446 edge_out->succ_next = NULL;
1448 edge_out->dest = old_succ;
1449 edge_out->flags = EDGE_FALLTHRU;
1450 edge_out->probability = REG_BR_PROB_BASE;
1451 edge_out->count = edge_in->count;
1453 old_succ->pred = edge_out;
1455 /* Tricky case -- if there existed a fallthru into the successor
1456 (and we're not it) we must add a new unconditional jump around
1457 the new block we're actually interested in.
1459 Further, if that edge is critical, this means a second new basic
1460 block must be created to hold it. In order to simplify correct
1461 insn placement, do this before we touch the existing basic block
1462 ordering for the block we were really wanting. */
1463 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1466 for (e = edge_out->pred_next; e ; e = e->pred_next)
1467 if (e->flags & EDGE_FALLTHRU)
1472 basic_block jump_block;
1475 if ((e->flags & EDGE_CRITICAL) == 0
1476 && e->src != ENTRY_BLOCK_PTR)
1478 /* Non critical -- we can simply add a jump to the end
1479 of the existing predecessor. */
1480 jump_block = e->src;
1484 /* We need a new block to hold the jump. The simplest
1485 way to do the bulk of the work here is to recursively
1487 jump_block = split_edge (e);
1488 e = jump_block->succ;
1491 /* Now add the jump insn ... */
1492 pos = emit_jump_insn_after (gen_jump (old_succ->head),
1494 jump_block->end = pos;
1495 if (basic_block_for_insn)
1496 set_block_for_insn (pos, jump_block);
1497 emit_barrier_after (pos);
1499 /* ... let jump know that label is in use, ... */
1500 JUMP_LABEL (pos) = old_succ->head;
1501 ++LABEL_NUSES (old_succ->head);
1503 /* ... and clear fallthru on the outgoing edge. */
1504 e->flags &= ~EDGE_FALLTHRU;
1506 /* Continue splitting the interesting edge. */
1510 /* Place the new block just in front of the successor. */
1511 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
1512 if (old_succ == EXIT_BLOCK_PTR)
1513 j = n_basic_blocks - 1;
1515 j = old_succ->index;
1516 for (i = n_basic_blocks - 1; i > j; --i)
1518 basic_block tmp = BASIC_BLOCK (i - 1);
1519 BASIC_BLOCK (i) = tmp;
1522 BASIC_BLOCK (i) = bb;
1525 /* Create the basic block note.
1527 Where we place the note can have a noticable impact on the generated
1528 code. Consider this cfg:
1539 If we need to insert an insn on the edge from block 0 to block 1,
1540 we want to ensure the instructions we insert are outside of any
1541 loop notes that physically sit between block 0 and block 1. Otherwise
1542 we confuse the loop optimizer into thinking the loop is a phony. */
1543 if (old_succ != EXIT_BLOCK_PTR
1544 && PREV_INSN (old_succ->head)
1545 && GET_CODE (PREV_INSN (old_succ->head)) == NOTE
1546 && NOTE_LINE_NUMBER (PREV_INSN (old_succ->head)) == NOTE_INSN_LOOP_BEG)
1547 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
1548 PREV_INSN (old_succ->head));
1549 else if (old_succ != EXIT_BLOCK_PTR)
1550 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, old_succ->head);
1552 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
1553 NOTE_BASIC_BLOCK (bb_note) = bb;
1554 bb->head = bb->end = bb_note;
1556 /* Not quite simple -- for non-fallthru edges, we must adjust the
1557 predecessor's jump instruction to target our new block. */
1558 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1560 rtx tmp, insn = old_pred->end;
1561 rtx old_label = old_succ->head;
1562 rtx new_label = gen_label_rtx ();
1564 if (GET_CODE (insn) != JUMP_INSN)
1567 /* ??? Recognize a tablejump and adjust all matching cases. */
1568 if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1569 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1570 && GET_CODE (tmp) == JUMP_INSN
1571 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1572 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1577 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1578 vec = XVEC (PATTERN (tmp), 0);
1580 vec = XVEC (PATTERN (tmp), 1);
1582 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1583 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
1585 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (VOIDmode, new_label);
1586 --LABEL_NUSES (old_label);
1587 ++LABEL_NUSES (new_label);
1590 /* Handle casesi dispatch insns */
1591 if ((tmp = single_set (insn)) != NULL
1592 && SET_DEST (tmp) == pc_rtx
1593 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1594 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
1595 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
1597 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (VOIDmode,
1599 --LABEL_NUSES (old_label);
1600 ++LABEL_NUSES (new_label);
1605 /* This would have indicated an abnormal edge. */
1606 if (computed_jump_p (insn))
1609 /* A return instruction can't be redirected. */
1610 if (returnjump_p (insn))
1613 /* If the insn doesn't go where we think, we're confused. */
1614 if (JUMP_LABEL (insn) != old_label)
1617 redirect_jump (insn, new_label, 0);
1620 emit_label_before (new_label, bb_note);
1621 bb->head = new_label;
1627 /* Queue instructions for insertion on an edge between two basic blocks.
1628 The new instructions and basic blocks (if any) will not appear in the
1629 CFG until commit_edge_insertions is called. */
1632 insert_insn_on_edge (pattern, e)
1636 /* We cannot insert instructions on an abnormal critical edge.
1637 It will be easier to find the culprit if we die now. */
1638 if ((e->flags & (EDGE_ABNORMAL|EDGE_CRITICAL))
1639 == (EDGE_ABNORMAL|EDGE_CRITICAL))
1642 if (e->insns == NULL_RTX)
1645 push_to_sequence (e->insns);
1647 emit_insn (pattern);
1649 e->insns = get_insns ();
1653 /* Update the CFG for the instructions queued on edge E. */
1656 commit_one_edge_insertion (e)
1659 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
1662 /* Pull the insns off the edge now since the edge might go away. */
1664 e->insns = NULL_RTX;
1666 /* Figure out where to put these things. If the destination has
1667 one predecessor, insert there. Except for the exit block. */
1668 if (e->dest->pred->pred_next == NULL
1669 && e->dest != EXIT_BLOCK_PTR)
1673 /* Get the location correct wrt a code label, and "nice" wrt
1674 a basic block note, and before everything else. */
1676 if (GET_CODE (tmp) == CODE_LABEL)
1677 tmp = NEXT_INSN (tmp);
1678 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
1679 tmp = NEXT_INSN (tmp);
1680 if (tmp == bb->head)
1683 after = PREV_INSN (tmp);
1686 /* If the source has one successor and the edge is not abnormal,
1687 insert there. Except for the entry block. */
1688 else if ((e->flags & EDGE_ABNORMAL) == 0
1689 && e->src->succ->succ_next == NULL
1690 && e->src != ENTRY_BLOCK_PTR)
1693 /* It is possible to have a non-simple jump here. Consider a target
1694 where some forms of unconditional jumps clobber a register. This
1695 happens on the fr30 for example.
1697 We know this block has a single successor, so we can just emit
1698 the queued insns before the jump. */
1699 if (GET_CODE (bb->end) == JUMP_INSN)
1705 /* We'd better be fallthru, or we've lost track of what's what. */
1706 if ((e->flags & EDGE_FALLTHRU) == 0)
1713 /* Otherwise we must split the edge. */
1716 bb = split_edge (e);
1720 /* Now that we've found the spot, do the insertion. */
1722 /* Set the new block number for these insns, if structure is allocated. */
1723 if (basic_block_for_insn)
1726 for (i = insns; i != NULL_RTX; i = NEXT_INSN (i))
1727 set_block_for_insn (i, bb);
1732 emit_insns_before (insns, before);
1733 if (before == bb->head)
1736 last = prev_nonnote_insn (before);
1740 last = emit_insns_after (insns, after);
1741 if (after == bb->end)
1745 if (returnjump_p (last))
1747 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1748 This is not currently a problem because this only happens
1749 for the (single) epilogue, which already has a fallthru edge
1753 if (e->dest != EXIT_BLOCK_PTR
1754 || e->succ_next != NULL
1755 || (e->flags & EDGE_FALLTHRU) == 0)
1757 e->flags &= ~EDGE_FALLTHRU;
1759 emit_barrier_after (last);
1763 flow_delete_insn (before);
1765 else if (GET_CODE (last) == JUMP_INSN)
1769 /* Update the CFG for all queued instructions. */
1772 commit_edge_insertions ()
1777 #ifdef ENABLE_CHECKING
1778 verify_flow_info ();
1782 bb = ENTRY_BLOCK_PTR;
1787 for (e = bb->succ; e ; e = next)
1789 next = e->succ_next;
1791 commit_one_edge_insertion (e);
1794 if (++i >= n_basic_blocks)
1796 bb = BASIC_BLOCK (i);
1800 /* Delete all unreachable basic blocks. */
1803 delete_unreachable_blocks ()
1805 basic_block *worklist, *tos;
1806 int deleted_handler;
1811 tos = worklist = (basic_block *) xmalloc (sizeof (basic_block) * n);
1813 /* Use basic_block->aux as a marker. Clear them all. */
1815 for (i = 0; i < n; ++i)
1816 BASIC_BLOCK (i)->aux = NULL;
1818 /* Add our starting points to the worklist. Almost always there will
1819 be only one. It isn't inconcievable that we might one day directly
1820 support Fortran alternate entry points. */
1822 for (e = ENTRY_BLOCK_PTR->succ; e ; e = e->succ_next)
1826 /* Mark the block with a handy non-null value. */
1830 /* Iterate: find everything reachable from what we've already seen. */
1832 while (tos != worklist)
1834 basic_block b = *--tos;
1836 for (e = b->succ; e ; e = e->succ_next)
1844 /* Delete all unreachable basic blocks. Count down so that we don't
1845 interfere with the block renumbering that happens in flow_delete_block. */
1847 deleted_handler = 0;
1849 for (i = n - 1; i >= 0; --i)
1851 basic_block b = BASIC_BLOCK (i);
1854 /* This block was found. Tidy up the mark. */
1857 deleted_handler |= flow_delete_block (b);
1860 tidy_fallthru_edges ();
1862 /* If we deleted an exception handler, we may have EH region begin/end
1863 blocks to remove as well. */
1864 if (deleted_handler)
1865 delete_eh_regions ();
1870 /* Find EH regions for which there is no longer a handler, and delete them. */
1873 delete_eh_regions ()
1877 update_rethrow_references ();
1879 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
1880 if (GET_CODE (insn) == NOTE)
1882 if ((NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG) ||
1883 (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
1885 int num = NOTE_EH_HANDLER (insn);
1886 /* A NULL handler indicates a region is no longer needed,
1887 as long as its rethrow label isn't used. */
1888 if (get_first_handler (num) == NULL && ! rethrow_used (num))
1890 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
1891 NOTE_SOURCE_FILE (insn) = 0;
1897 /* Return true if NOTE is not one of the ones that must be kept paired,
1898 so that we may simply delete them. */
1901 can_delete_note_p (note)
1904 return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED
1905 || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK);
1908 /* Unlink a chain of insns between START and FINISH, leaving notes
1909 that must be paired. */
1912 flow_delete_insn_chain (start, finish)
1915 /* Unchain the insns one by one. It would be quicker to delete all
1916 of these with a single unchaining, rather than one at a time, but
1917 we need to keep the NOTE's. */
1923 next = NEXT_INSN (start);
1924 if (GET_CODE (start) == NOTE && !can_delete_note_p (start))
1926 else if (GET_CODE (start) == CODE_LABEL
1927 && ! can_delete_label_p (start))
1929 const char *name = LABEL_NAME (start);
1930 PUT_CODE (start, NOTE);
1931 NOTE_LINE_NUMBER (start) = NOTE_INSN_DELETED_LABEL;
1932 NOTE_SOURCE_FILE (start) = name;
1935 next = flow_delete_insn (start);
1937 if (start == finish)
1943 /* Delete the insns in a (non-live) block. We physically delete every
1944 non-deleted-note insn, and update the flow graph appropriately.
1946 Return nonzero if we deleted an exception handler. */
1948 /* ??? Preserving all such notes strikes me as wrong. It would be nice
1949 to post-process the stream to remove empty blocks, loops, ranges, etc. */
1952 flow_delete_block (b)
1955 int deleted_handler = 0;
1958 /* If the head of this block is a CODE_LABEL, then it might be the
1959 label for an exception handler which can't be reached.
1961 We need to remove the label from the exception_handler_label list
1962 and remove the associated NOTE_INSN_EH_REGION_BEG and
1963 NOTE_INSN_EH_REGION_END notes. */
1967 never_reached_warning (insn);
1969 if (GET_CODE (insn) == CODE_LABEL)
1971 rtx x, *prev = &exception_handler_labels;
1973 for (x = exception_handler_labels; x; x = XEXP (x, 1))
1975 if (XEXP (x, 0) == insn)
1977 /* Found a match, splice this label out of the EH label list. */
1978 *prev = XEXP (x, 1);
1979 XEXP (x, 1) = NULL_RTX;
1980 XEXP (x, 0) = NULL_RTX;
1982 /* Remove the handler from all regions */
1983 remove_handler (insn);
1984 deleted_handler = 1;
1987 prev = &XEXP (x, 1);
1991 /* Include any jump table following the basic block. */
1993 if (GET_CODE (end) == JUMP_INSN
1994 && (tmp = JUMP_LABEL (end)) != NULL_RTX
1995 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1996 && GET_CODE (tmp) == JUMP_INSN
1997 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1998 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
2001 /* Include any barrier that may follow the basic block. */
2002 tmp = next_nonnote_insn (end);
2003 if (tmp && GET_CODE (tmp) == BARRIER)
2006 /* Selectively delete the entire chain. */
2007 flow_delete_insn_chain (insn, end);
2009 /* Remove the edges into and out of this block. Note that there may
2010 indeed be edges in, if we are removing an unreachable loop. */
2014 for (e = b->pred; e ; e = next)
2016 for (q = &e->src->succ; *q != e; q = &(*q)->succ_next)
2019 next = e->pred_next;
2023 for (e = b->succ; e ; e = next)
2025 for (q = &e->dest->pred; *q != e; q = &(*q)->pred_next)
2028 next = e->succ_next;
2037 /* Remove the basic block from the array, and compact behind it. */
2040 return deleted_handler;
2043 /* Remove block B from the basic block array and compact behind it. */
2049 int i, n = n_basic_blocks;
2051 for (i = b->index; i + 1 < n; ++i)
2053 basic_block x = BASIC_BLOCK (i + 1);
2054 BASIC_BLOCK (i) = x;
2058 basic_block_info->num_elements--;
2062 /* Delete INSN by patching it out. Return the next insn. */
2065 flow_delete_insn (insn)
2068 rtx prev = PREV_INSN (insn);
2069 rtx next = NEXT_INSN (insn);
2072 PREV_INSN (insn) = NULL_RTX;
2073 NEXT_INSN (insn) = NULL_RTX;
2074 INSN_DELETED_P (insn) = 1;
2077 NEXT_INSN (prev) = next;
2079 PREV_INSN (next) = prev;
2081 set_last_insn (prev);
2083 if (GET_CODE (insn) == CODE_LABEL)
2084 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2086 /* If deleting a jump, decrement the use count of the label. Deleting
2087 the label itself should happen in the normal course of block merging. */
2088 if (GET_CODE (insn) == JUMP_INSN
2089 && JUMP_LABEL (insn)
2090 && GET_CODE (JUMP_LABEL (insn)) == CODE_LABEL)
2091 LABEL_NUSES (JUMP_LABEL (insn))--;
2093 /* Also if deleting an insn that references a label. */
2094 else if ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX
2095 && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
2096 LABEL_NUSES (XEXP (note, 0))--;
2101 /* True if a given label can be deleted. */
2104 can_delete_label_p (label)
2109 if (LABEL_PRESERVE_P (label))
2112 for (x = forced_labels; x ; x = XEXP (x, 1))
2113 if (label == XEXP (x, 0))
2115 for (x = label_value_list; x ; x = XEXP (x, 1))
2116 if (label == XEXP (x, 0))
2118 for (x = exception_handler_labels; x ; x = XEXP (x, 1))
2119 if (label == XEXP (x, 0))
2122 /* User declared labels must be preserved. */
2123 if (LABEL_NAME (label) != 0)
2130 tail_recursion_label_p (label)
2135 for (x = tail_recursion_label_list; x ; x = XEXP (x, 1))
2136 if (label == XEXP (x, 0))
2142 /* Blocks A and B are to be merged into a single block A. The insns
2143 are already contiguous, hence `nomove'. */
2146 merge_blocks_nomove (a, b)
2150 rtx b_head, b_end, a_end;
2151 rtx del_first = NULL_RTX, del_last = NULL_RTX;
2154 /* If there was a CODE_LABEL beginning B, delete it. */
2157 if (GET_CODE (b_head) == CODE_LABEL)
2159 /* Detect basic blocks with nothing but a label. This can happen
2160 in particular at the end of a function. */
2161 if (b_head == b_end)
2163 del_first = del_last = b_head;
2164 b_head = NEXT_INSN (b_head);
2167 /* Delete the basic block note. */
2168 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
2170 if (b_head == b_end)
2175 b_head = NEXT_INSN (b_head);
2178 /* If there was a jump out of A, delete it. */
2180 if (GET_CODE (a_end) == JUMP_INSN)
2184 prev = prev_nonnote_insn (a_end);
2191 /* If this was a conditional jump, we need to also delete
2192 the insn that set cc0. */
2193 if (prev && sets_cc0_p (prev))
2196 prev = prev_nonnote_insn (prev);
2205 else if (GET_CODE (NEXT_INSN (a_end)) == BARRIER)
2206 del_first = NEXT_INSN (a_end);
2208 /* Delete everything marked above as well as crap that might be
2209 hanging out between the two blocks. */
2210 flow_delete_insn_chain (del_first, del_last);
2212 /* Normally there should only be one successor of A and that is B, but
2213 partway though the merge of blocks for conditional_execution we'll
2214 be merging a TEST block with THEN and ELSE successors. Free the
2215 whole lot of them and hope the caller knows what they're doing. */
2217 remove_edge (a->succ);
2219 /* Adjust the edges out of B for the new owner. */
2220 for (e = b->succ; e ; e = e->succ_next)
2224 /* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */
2225 b->pred = b->succ = NULL;
2227 /* Reassociate the insns of B with A. */
2230 if (basic_block_for_insn)
2232 BLOCK_FOR_INSN (b_head) = a;
2233 while (b_head != b_end)
2235 b_head = NEXT_INSN (b_head);
2236 BLOCK_FOR_INSN (b_head) = a;
2246 /* Blocks A and B are to be merged into a single block. A has no incoming
2247 fallthru edge, so it can be moved before B without adding or modifying
2248 any jumps (aside from the jump from A to B). */
2251 merge_blocks_move_predecessor_nojumps (a, b)
2254 rtx start, end, barrier;
2260 barrier = next_nonnote_insn (end);
2261 if (GET_CODE (barrier) != BARRIER)
2263 flow_delete_insn (barrier);
2265 /* Move block and loop notes out of the chain so that we do not
2266 disturb their order.
2268 ??? A better solution would be to squeeze out all the non-nested notes
2269 and adjust the block trees appropriately. Even better would be to have
2270 a tighter connection between block trees and rtl so that this is not
2272 start = squeeze_notes (start, end);
2274 /* Scramble the insn chain. */
2275 if (end != PREV_INSN (b->head))
2276 reorder_insns (start, end, PREV_INSN (b->head));
2280 fprintf (rtl_dump_file, "Moved block %d before %d and merged.\n",
2281 a->index, b->index);
2284 /* Swap the records for the two blocks around. Although we are deleting B,
2285 A is now where B was and we want to compact the BB array from where
2287 BASIC_BLOCK(a->index) = b;
2288 BASIC_BLOCK(b->index) = a;
2290 a->index = b->index;
2293 /* Now blocks A and B are contiguous. Merge them. */
2294 merge_blocks_nomove (a, b);
2299 /* Blocks A and B are to be merged into a single block. B has no outgoing
2300 fallthru edge, so it can be moved after A without adding or modifying
2301 any jumps (aside from the jump from A to B). */
2304 merge_blocks_move_successor_nojumps (a, b)
2307 rtx start, end, barrier;
2311 barrier = NEXT_INSN (end);
2313 /* Recognize a jump table following block B. */
2314 if (GET_CODE (barrier) == CODE_LABEL
2315 && NEXT_INSN (barrier)
2316 && GET_CODE (NEXT_INSN (barrier)) == JUMP_INSN
2317 && (GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_VEC
2318 || GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_DIFF_VEC))
2320 end = NEXT_INSN (barrier);
2321 barrier = NEXT_INSN (end);
2324 /* There had better have been a barrier there. Delete it. */
2325 if (GET_CODE (barrier) != BARRIER)
2327 flow_delete_insn (barrier);
2329 /* Move block and loop notes out of the chain so that we do not
2330 disturb their order.
2332 ??? A better solution would be to squeeze out all the non-nested notes
2333 and adjust the block trees appropriately. Even better would be to have
2334 a tighter connection between block trees and rtl so that this is not
2336 start = squeeze_notes (start, end);
2338 /* Scramble the insn chain. */
2339 reorder_insns (start, end, a->end);
2341 /* Now blocks A and B are contiguous. Merge them. */
2342 merge_blocks_nomove (a, b);
2346 fprintf (rtl_dump_file, "Moved block %d after %d and merged.\n",
2347 b->index, a->index);
2353 /* Attempt to merge basic blocks that are potentially non-adjacent.
2354 Return true iff the attempt succeeded. */
2357 merge_blocks (e, b, c)
2361 /* If C has a tail recursion label, do not merge. There is no
2362 edge recorded from the call_placeholder back to this label, as
2363 that would make optimize_sibling_and_tail_recursive_calls more
2364 complex for no gain. */
2365 if (GET_CODE (c->head) == CODE_LABEL
2366 && tail_recursion_label_p (c->head))
2369 /* If B has a fallthru edge to C, no need to move anything. */
2370 if (e->flags & EDGE_FALLTHRU)
2372 merge_blocks_nomove (b, c);
2376 fprintf (rtl_dump_file, "Merged %d and %d without moving.\n",
2377 b->index, c->index);
2386 int c_has_outgoing_fallthru;
2387 int b_has_incoming_fallthru;
2389 /* We must make sure to not munge nesting of exception regions,
2390 lexical blocks, and loop notes.
2392 The first is taken care of by requiring that the active eh
2393 region at the end of one block always matches the active eh
2394 region at the beginning of the next block.
2396 The later two are taken care of by squeezing out all the notes. */
2398 /* ??? A throw/catch edge (or any abnormal edge) should be rarely
2399 executed and we may want to treat blocks which have two out
2400 edges, one normal, one abnormal as only having one edge for
2401 block merging purposes. */
2403 for (tmp_edge = c->succ; tmp_edge ; tmp_edge = tmp_edge->succ_next)
2404 if (tmp_edge->flags & EDGE_FALLTHRU)
2406 c_has_outgoing_fallthru = (tmp_edge != NULL);
2408 for (tmp_edge = b->pred; tmp_edge ; tmp_edge = tmp_edge->pred_next)
2409 if (tmp_edge->flags & EDGE_FALLTHRU)
2411 b_has_incoming_fallthru = (tmp_edge != NULL);
2413 /* If B does not have an incoming fallthru, and the exception regions
2414 match, then it can be moved immediately before C without introducing
2417 C can not be the first block, so we do not have to worry about
2418 accessing a non-existent block. */
2419 d = BASIC_BLOCK (c->index - 1);
2420 if (! b_has_incoming_fallthru
2421 && d->eh_end == b->eh_beg
2422 && b->eh_end == c->eh_beg)
2423 return merge_blocks_move_predecessor_nojumps (b, c);
2425 /* Otherwise, we're going to try to move C after B. Make sure the
2426 exception regions match.
2428 If B is the last basic block, then we must not try to access the
2429 block structure for block B + 1. Luckily in that case we do not
2430 need to worry about matching exception regions. */
2431 d = (b->index + 1 < n_basic_blocks ? BASIC_BLOCK (b->index + 1) : NULL);
2432 if (b->eh_end == c->eh_beg
2433 && (d == NULL || c->eh_end == d->eh_beg))
2435 /* If C does not have an outgoing fallthru, then it can be moved
2436 immediately after B without introducing or modifying jumps. */
2437 if (! c_has_outgoing_fallthru)
2438 return merge_blocks_move_successor_nojumps (b, c);
2440 /* Otherwise, we'll need to insert an extra jump, and possibly
2441 a new block to contain it. */
2442 /* ??? Not implemented yet. */
2449 /* Top level driver for merge_blocks. */
2456 /* Attempt to merge blocks as made possible by edge removal. If a block
2457 has only one successor, and the successor has only one predecessor,
2458 they may be combined. */
2460 for (i = 0; i < n_basic_blocks; )
2462 basic_block c, b = BASIC_BLOCK (i);
2465 /* A loop because chains of blocks might be combineable. */
2466 while ((s = b->succ) != NULL
2467 && s->succ_next == NULL
2468 && (s->flags & EDGE_EH) == 0
2469 && (c = s->dest) != EXIT_BLOCK_PTR
2470 && c->pred->pred_next == NULL
2471 /* If the jump insn has side effects, we can't kill the edge. */
2472 && (GET_CODE (b->end) != JUMP_INSN
2473 || onlyjump_p (b->end))
2474 && merge_blocks (s, b, c))
2477 /* Don't get confused by the index shift caused by deleting blocks. */
2482 /* The given edge should potentially be a fallthru edge. If that is in
2483 fact true, delete the jump and barriers that are in the way. */
2486 tidy_fallthru_edge (e, b, c)
2492 /* ??? In a late-running flow pass, other folks may have deleted basic
2493 blocks by nopping out blocks, leaving multiple BARRIERs between here
2494 and the target label. They ought to be chastized and fixed.
2496 We can also wind up with a sequence of undeletable labels between
2497 one block and the next.
2499 So search through a sequence of barriers, labels, and notes for
2500 the head of block C and assert that we really do fall through. */
2502 if (next_real_insn (b->end) != next_real_insn (PREV_INSN (c->head)))
2505 /* Remove what will soon cease being the jump insn from the source block.
2506 If block B consisted only of this single jump, turn it into a deleted
2509 if (GET_CODE (q) == JUMP_INSN
2511 && (any_uncondjump_p (q)
2512 || (b->succ == e && e->succ_next == NULL)))
2515 /* If this was a conditional jump, we need to also delete
2516 the insn that set cc0. */
2517 if (any_condjump_p (q) && sets_cc0_p (PREV_INSN (q)))
2524 NOTE_LINE_NUMBER (q) = NOTE_INSN_DELETED;
2525 NOTE_SOURCE_FILE (q) = 0;
2528 b->end = q = PREV_INSN (q);
2531 /* Selectively unlink the sequence. */
2532 if (q != PREV_INSN (c->head))
2533 flow_delete_insn_chain (NEXT_INSN (q), PREV_INSN (c->head));
2535 e->flags |= EDGE_FALLTHRU;
2538 /* Fix up edges that now fall through, or rather should now fall through
2539 but previously required a jump around now deleted blocks. Simplify
2540 the search by only examining blocks numerically adjacent, since this
2541 is how find_basic_blocks created them. */
2544 tidy_fallthru_edges ()
2548 for (i = 1; i < n_basic_blocks; ++i)
2550 basic_block b = BASIC_BLOCK (i - 1);
2551 basic_block c = BASIC_BLOCK (i);
2554 /* We care about simple conditional or unconditional jumps with
2557 If we had a conditional branch to the next instruction when
2558 find_basic_blocks was called, then there will only be one
2559 out edge for the block which ended with the conditional
2560 branch (since we do not create duplicate edges).
2562 Furthermore, the edge will be marked as a fallthru because we
2563 merge the flags for the duplicate edges. So we do not want to
2564 check that the edge is not a FALLTHRU edge. */
2565 if ((s = b->succ) != NULL
2566 && s->succ_next == NULL
2568 /* If the jump insn has side effects, we can't tidy the edge. */
2569 && (GET_CODE (b->end) != JUMP_INSN
2570 || onlyjump_p (b->end)))
2571 tidy_fallthru_edge (s, b, c);
2575 /* Perform data flow analysis.
2576 F is the first insn of the function; FLAGS is a set of PROP_* flags
2577 to be used in accumulating flow info. */
2580 life_analysis (f, file, flags)
2585 #ifdef ELIMINABLE_REGS
2587 static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
2590 /* Record which registers will be eliminated. We use this in
2593 CLEAR_HARD_REG_SET (elim_reg_set);
2595 #ifdef ELIMINABLE_REGS
2596 for (i = 0; i < (int) (sizeof eliminables / sizeof eliminables[0]); i++)
2597 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
2599 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
2603 flags &= PROP_DEATH_NOTES | PROP_REG_INFO;
2605 /* The post-reload life analysis have (on a global basis) the same
2606 registers live as was computed by reload itself. elimination
2607 Otherwise offsets and such may be incorrect.
2609 Reload will make some registers as live even though they do not
2612 We don't want to create new auto-incs after reload, since they
2613 are unlikely to be useful and can cause problems with shared
2615 if (reload_completed)
2616 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
2618 /* We want alias analysis information for local dead store elimination. */
2619 if (flags & PROP_SCAN_DEAD_CODE)
2620 init_alias_analysis ();
2622 /* Always remove no-op moves. Do this before other processing so
2623 that we don't have to keep re-scanning them. */
2624 delete_noop_moves (f);
2626 /* Some targets can emit simpler epilogues if they know that sp was
2627 not ever modified during the function. After reload, of course,
2628 we've already emitted the epilogue so there's no sense searching. */
2629 if (! reload_completed)
2630 notice_stack_pointer_modification (f);
2632 /* Allocate and zero out data structures that will record the
2633 data from lifetime analysis. */
2634 allocate_reg_life_data ();
2635 allocate_bb_life_data ();
2637 /* Find the set of registers live on function exit. */
2638 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
2640 /* "Update" life info from zero. It'd be nice to begin the
2641 relaxation with just the exit and noreturn blocks, but that set
2642 is not immediately handy. */
2644 if (flags & PROP_REG_INFO)
2645 memset (regs_ever_live, 0, sizeof(regs_ever_live));
2646 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
2649 if (flags & PROP_SCAN_DEAD_CODE)
2650 end_alias_analysis ();
2653 dump_flow_info (file);
2655 free_basic_block_vars (1);
2658 /* A subroutine of verify_wide_reg, called through for_each_rtx.
2659 Search for REGNO. If found, abort if it is not wider than word_mode. */
2662 verify_wide_reg_1 (px, pregno)
2667 unsigned int regno = *(int *) pregno;
2669 if (GET_CODE (x) == REG && REGNO (x) == regno)
2671 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
2678 /* A subroutine of verify_local_live_at_start. Search through insns
2679 between HEAD and END looking for register REGNO. */
2682 verify_wide_reg (regno, head, end)
2688 if (GET_RTX_CLASS (GET_CODE (head)) == 'i'
2689 && for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no))
2693 head = NEXT_INSN (head);
2696 /* We didn't find the register at all. Something's way screwy. */
2700 /* A subroutine of update_life_info. Verify that there are no untoward
2701 changes in live_at_start during a local update. */
2704 verify_local_live_at_start (new_live_at_start, bb)
2705 regset new_live_at_start;
2708 if (reload_completed)
2710 /* After reload, there are no pseudos, nor subregs of multi-word
2711 registers. The regsets should exactly match. */
2712 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
2719 /* Find the set of changed registers. */
2720 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
2722 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
2724 /* No registers should die. */
2725 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
2727 /* Verify that the now-live register is wider than word_mode. */
2728 verify_wide_reg (i, bb->head, bb->end);
2733 /* Updates life information starting with the basic blocks set in BLOCKS.
2734 If BLOCKS is null, consider it to be the universal set.
2736 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
2737 we are only expecting local modifications to basic blocks. If we find
2738 extra registers live at the beginning of a block, then we either killed
2739 useful data, or we have a broken split that wants data not provided.
2740 If we find registers removed from live_at_start, that means we have
2741 a broken peephole that is killing a register it shouldn't.
2743 ??? This is not true in one situation -- when a pre-reload splitter
2744 generates subregs of a multi-word pseudo, current life analysis will
2745 lose the kill. So we _can_ have a pseudo go live. How irritating.
2747 Including PROP_REG_INFO does not properly refresh regs_ever_live
2748 unless the caller resets it to zero. */
2751 update_life_info (blocks, extent, prop_flags)
2753 enum update_life_extent extent;
2757 regset_head tmp_head;
2760 tmp = INITIALIZE_REG_SET (tmp_head);
2762 /* For a global update, we go through the relaxation process again. */
2763 if (extent != UPDATE_LIFE_LOCAL)
2765 calculate_global_regs_live (blocks, blocks,
2766 prop_flags & PROP_SCAN_DEAD_CODE);
2768 /* If asked, remove notes from the blocks we'll update. */
2769 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
2770 count_or_remove_death_notes (blocks, 1);
2775 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
2777 basic_block bb = BASIC_BLOCK (i);
2779 COPY_REG_SET (tmp, bb->global_live_at_end);
2780 propagate_block (bb, tmp, (regset) NULL, prop_flags);
2782 if (extent == UPDATE_LIFE_LOCAL)
2783 verify_local_live_at_start (tmp, bb);
2788 for (i = n_basic_blocks - 1; i >= 0; --i)
2790 basic_block bb = BASIC_BLOCK (i);
2792 COPY_REG_SET (tmp, bb->global_live_at_end);
2793 propagate_block (bb, tmp, (regset) NULL, prop_flags);
2795 if (extent == UPDATE_LIFE_LOCAL)
2796 verify_local_live_at_start (tmp, bb);
2802 if (prop_flags & PROP_REG_INFO)
2804 /* The only pseudos that are live at the beginning of the function
2805 are those that were not set anywhere in the function. local-alloc
2806 doesn't know how to handle these correctly, so mark them as not
2807 local to any one basic block. */
2808 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
2809 FIRST_PSEUDO_REGISTER, i,
2810 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
2812 /* We have a problem with any pseudoreg that lives across the setjmp.
2813 ANSI says that if a user variable does not change in value between
2814 the setjmp and the longjmp, then the longjmp preserves it. This
2815 includes longjmp from a place where the pseudo appears dead.
2816 (In principle, the value still exists if it is in scope.)
2817 If the pseudo goes in a hard reg, some other value may occupy
2818 that hard reg where this pseudo is dead, thus clobbering the pseudo.
2819 Conclusion: such a pseudo must not go in a hard reg. */
2820 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
2821 FIRST_PSEUDO_REGISTER, i,
2823 if (regno_reg_rtx[i] != 0)
2825 REG_LIVE_LENGTH (i) = -1;
2826 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
2832 /* Free the variables allocated by find_basic_blocks.
2834 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
2837 free_basic_block_vars (keep_head_end_p)
2838 int keep_head_end_p;
2840 if (basic_block_for_insn)
2842 VARRAY_FREE (basic_block_for_insn);
2843 basic_block_for_insn = NULL;
2846 if (! keep_head_end_p)
2849 VARRAY_FREE (basic_block_info);
2852 ENTRY_BLOCK_PTR->aux = NULL;
2853 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
2854 EXIT_BLOCK_PTR->aux = NULL;
2855 EXIT_BLOCK_PTR->global_live_at_start = NULL;
2859 /* Return nonzero if the destination of SET equals the source. */
2864 rtx src = SET_SRC (set);
2865 rtx dst = SET_DEST (set);
2867 if (GET_CODE (src) == SUBREG && GET_CODE (dst) == SUBREG)
2869 if (SUBREG_WORD (src) != SUBREG_WORD (dst))
2871 src = SUBREG_REG (src);
2872 dst = SUBREG_REG (dst);
2875 return (GET_CODE (src) == REG && GET_CODE (dst) == REG
2876 && REGNO (src) == REGNO (dst));
2879 /* Return nonzero if an insn consists only of SETs, each of which only sets a
2885 rtx pat = PATTERN (insn);
2887 /* Insns carrying these notes are useful later on. */
2888 if (find_reg_note (insn, REG_EQUAL, NULL_RTX))
2891 if (GET_CODE (pat) == SET && set_noop_p (pat))
2894 if (GET_CODE (pat) == PARALLEL)
2897 /* If nothing but SETs of registers to themselves,
2898 this insn can also be deleted. */
2899 for (i = 0; i < XVECLEN (pat, 0); i++)
2901 rtx tem = XVECEXP (pat, 0, i);
2903 if (GET_CODE (tem) == USE
2904 || GET_CODE (tem) == CLOBBER)
2907 if (GET_CODE (tem) != SET || ! set_noop_p (tem))
2916 /* Delete any insns that copy a register to itself. */
2919 delete_noop_moves (f)
2923 for (insn = f; insn; insn = NEXT_INSN (insn))
2925 if (GET_CODE (insn) == INSN && noop_move_p (insn))
2927 PUT_CODE (insn, NOTE);
2928 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
2929 NOTE_SOURCE_FILE (insn) = 0;
2934 /* Determine if the stack pointer is constant over the life of the function.
2935 Only useful before prologues have been emitted. */
2938 notice_stack_pointer_modification_1 (x, pat, data)
2940 rtx pat ATTRIBUTE_UNUSED;
2941 void *data ATTRIBUTE_UNUSED;
2943 if (x == stack_pointer_rtx
2944 /* The stack pointer is only modified indirectly as the result
2945 of a push until later in flow. See the comments in rtl.texi
2946 regarding Embedded Side-Effects on Addresses. */
2947 || (GET_CODE (x) == MEM
2948 && (GET_CODE (XEXP (x, 0)) == PRE_DEC
2949 || GET_CODE (XEXP (x, 0)) == PRE_INC
2950 || GET_CODE (XEXP (x, 0)) == POST_DEC
2951 || GET_CODE (XEXP (x, 0)) == POST_INC)
2952 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
2953 current_function_sp_is_unchanging = 0;
2957 notice_stack_pointer_modification (f)
2962 /* Assume that the stack pointer is unchanging if alloca hasn't
2964 current_function_sp_is_unchanging = !current_function_calls_alloca;
2965 if (! current_function_sp_is_unchanging)
2968 for (insn = f; insn; insn = NEXT_INSN (insn))
2970 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
2972 /* Check if insn modifies the stack pointer. */
2973 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
2975 if (! current_function_sp_is_unchanging)
2981 /* Mark a register in SET. Hard registers in large modes get all
2982 of their component registers set as well. */
2984 mark_reg (reg, xset)
2988 regset set = (regset) xset;
2989 int regno = REGNO (reg);
2991 if (GET_MODE (reg) == BLKmode)
2994 SET_REGNO_REG_SET (set, regno);
2995 if (regno < FIRST_PSEUDO_REGISTER)
2997 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
2999 SET_REGNO_REG_SET (set, regno + n);
3003 /* Mark those regs which are needed at the end of the function as live
3004 at the end of the last basic block. */
3006 mark_regs_live_at_end (set)
3011 /* If exiting needs the right stack value, consider the stack pointer
3012 live at the end of the function. */
3013 if ((HAVE_epilogue && reload_completed)
3014 || ! EXIT_IGNORE_STACK
3015 || (! FRAME_POINTER_REQUIRED
3016 && ! current_function_calls_alloca
3017 && flag_omit_frame_pointer)
3018 || current_function_sp_is_unchanging)
3020 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
3023 /* Mark the frame pointer if needed at the end of the function. If
3024 we end up eliminating it, it will be removed from the live list
3025 of each basic block by reload. */
3027 if (! reload_completed || frame_pointer_needed)
3029 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
3030 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3031 /* If they are different, also mark the hard frame pointer as live */
3032 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
3036 #ifdef PIC_OFFSET_TABLE_REGNUM
3037 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
3038 /* Many architectures have a GP register even without flag_pic.
3039 Assume the pic register is not in use, or will be handled by
3040 other means, if it is not fixed. */
3041 if (fixed_regs[PIC_OFFSET_TABLE_REGNUM])
3042 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
3046 /* Mark all global registers, and all registers used by the epilogue
3047 as being live at the end of the function since they may be
3048 referenced by our caller. */
3049 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3051 #ifdef EPILOGUE_USES
3052 || EPILOGUE_USES (i)
3055 SET_REGNO_REG_SET (set, i);
3057 /* Mark all call-saved registers that we actaully used. */
3058 if (HAVE_epilogue && reload_completed)
3060 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3061 if (! call_used_regs[i] && regs_ever_live[i])
3062 SET_REGNO_REG_SET (set, i);
3065 /* Mark function return value. */
3066 diddle_return_value (mark_reg, set);
3069 /* Callback function for for_each_successor_phi. DATA is a regset.
3070 Sets the SRC_REGNO, the regno of the phi alternative for phi node
3071 INSN, in the regset. */
3074 set_phi_alternative_reg (insn, dest_regno, src_regno, data)
3075 rtx insn ATTRIBUTE_UNUSED;
3076 int dest_regno ATTRIBUTE_UNUSED;
3080 regset live = (regset) data;
3081 SET_REGNO_REG_SET (live, src_regno);
3085 /* Propagate global life info around the graph of basic blocks. Begin
3086 considering blocks with their corresponding bit set in BLOCKS_IN.
3087 If BLOCKS_IN is null, consider it the universal set.
3089 BLOCKS_OUT is set for every block that was changed. */
3092 calculate_global_regs_live (blocks_in, blocks_out, flags)
3093 sbitmap blocks_in, blocks_out;
3096 basic_block *queue, *qhead, *qtail, *qend;
3097 regset tmp, new_live_at_end;
3098 regset_head tmp_head;
3099 regset_head new_live_at_end_head;
3102 tmp = INITIALIZE_REG_SET (tmp_head);
3103 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
3105 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
3106 because the `head == tail' style test for an empty queue doesn't
3107 work with a full queue. */
3108 queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
3110 qhead = qend = queue + n_basic_blocks + 2;
3112 /* Clear out the garbage that might be hanging out in bb->aux. */
3113 for (i = n_basic_blocks - 1; i >= 0; --i)
3114 BASIC_BLOCK (i)->aux = NULL;
3116 /* Queue the blocks set in the initial mask. Do this in reverse block
3117 number order so that we are more likely for the first round to do
3118 useful work. We use AUX non-null to flag that the block is queued. */
3121 EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
3123 basic_block bb = BASIC_BLOCK (i);
3130 for (i = 0; i < n_basic_blocks; ++i)
3132 basic_block bb = BASIC_BLOCK (i);
3139 sbitmap_zero (blocks_out);
3141 while (qhead != qtail)
3143 int rescan, changed;
3152 /* Begin by propogating live_at_start from the successor blocks. */
3153 CLEAR_REG_SET (new_live_at_end);
3154 for (e = bb->succ; e ; e = e->succ_next)
3156 basic_block sb = e->dest;
3157 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
3160 /* Force the stack pointer to be live -- which might not already be
3161 the case for blocks within infinite loops. */
3162 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
3164 /* Regs used in phi nodes are not included in
3165 global_live_at_start, since they are live only along a
3166 particular edge. Set those regs that are live because of a
3167 phi node alternative corresponding to this particular block. */
3169 for_each_successor_phi (bb, &set_phi_alternative_reg,
3172 if (bb == ENTRY_BLOCK_PTR)
3174 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3178 /* On our first pass through this block, we'll go ahead and continue.
3179 Recognize first pass by local_set NULL. On subsequent passes, we
3180 get to skip out early if live_at_end wouldn't have changed. */
3182 if (bb->local_set == NULL)
3184 bb->local_set = OBSTACK_ALLOC_REG_SET (function_obstack);
3189 /* If any bits were removed from live_at_end, we'll have to
3190 rescan the block. This wouldn't be necessary if we had
3191 precalculated local_live, however with PROP_SCAN_DEAD_CODE
3192 local_live is really dependent on live_at_end. */
3193 CLEAR_REG_SET (tmp);
3194 rescan = bitmap_operation (tmp, bb->global_live_at_end,
3195 new_live_at_end, BITMAP_AND_COMPL);
3199 /* Find the set of changed bits. Take this opportunity
3200 to notice that this set is empty and early out. */
3201 CLEAR_REG_SET (tmp);
3202 changed = bitmap_operation (tmp, bb->global_live_at_end,
3203 new_live_at_end, BITMAP_XOR);
3207 /* If any of the changed bits overlap with local_set,
3208 we'll have to rescan the block. Detect overlap by
3209 the AND with ~local_set turning off bits. */
3210 rescan = bitmap_operation (tmp, tmp, bb->local_set,
3215 /* Let our caller know that BB changed enough to require its
3216 death notes updated. */
3218 SET_BIT (blocks_out, bb->index);
3222 /* Add to live_at_start the set of all registers in
3223 new_live_at_end that aren't in the old live_at_end. */
3225 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
3227 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3229 changed = bitmap_operation (bb->global_live_at_start,
3230 bb->global_live_at_start,
3237 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3239 /* Rescan the block insn by insn to turn (a copy of) live_at_end
3240 into live_at_start. */
3241 propagate_block (bb, new_live_at_end, bb->local_set, flags);
3243 /* If live_at start didn't change, no need to go farther. */
3244 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
3247 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
3250 /* Queue all predecessors of BB so that we may re-examine
3251 their live_at_end. */
3252 for (e = bb->pred; e ; e = e->pred_next)
3254 basic_block pb = e->src;
3255 if (pb->aux == NULL)
3266 FREE_REG_SET (new_live_at_end);
3270 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
3272 basic_block bb = BASIC_BLOCK (i);
3273 FREE_REG_SET (bb->local_set);
3278 for (i = n_basic_blocks - 1; i >= 0; --i)
3280 basic_block bb = BASIC_BLOCK (i);
3281 FREE_REG_SET (bb->local_set);
3288 /* Subroutines of life analysis. */
3290 /* Allocate the permanent data structures that represent the results
3291 of life analysis. Not static since used also for stupid life analysis. */
3294 allocate_bb_life_data ()
3298 for (i = 0; i < n_basic_blocks; i++)
3300 basic_block bb = BASIC_BLOCK (i);
3302 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (function_obstack);
3303 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (function_obstack);
3306 ENTRY_BLOCK_PTR->global_live_at_end
3307 = OBSTACK_ALLOC_REG_SET (function_obstack);
3308 EXIT_BLOCK_PTR->global_live_at_start
3309 = OBSTACK_ALLOC_REG_SET (function_obstack);
3311 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (function_obstack);
3315 allocate_reg_life_data ()
3319 max_regno = max_reg_num ();
3321 /* Recalculate the register space, in case it has grown. Old style
3322 vector oriented regsets would set regset_{size,bytes} here also. */
3323 allocate_reg_info (max_regno, FALSE, FALSE);
3325 /* Reset all the data we'll collect in propagate_block and its
3327 for (i = 0; i < max_regno; i++)
3331 REG_N_DEATHS (i) = 0;
3332 REG_N_CALLS_CROSSED (i) = 0;
3333 REG_LIVE_LENGTH (i) = 0;
3334 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
3338 /* Delete dead instructions for propagate_block. */
3341 propagate_block_delete_insn (bb, insn)
3345 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
3347 /* If the insn referred to a label, and that label was attached to
3348 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
3349 pretty much mandatory to delete it, because the ADDR_VEC may be
3350 referencing labels that no longer exist. */
3354 rtx label = XEXP (inote, 0);
3357 if (LABEL_NUSES (label) == 1
3358 && (next = next_nonnote_insn (label)) != NULL
3359 && GET_CODE (next) == JUMP_INSN
3360 && (GET_CODE (PATTERN (next)) == ADDR_VEC
3361 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
3363 rtx pat = PATTERN (next);
3364 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
3365 int len = XVECLEN (pat, diff_vec_p);
3368 for (i = 0; i < len; i++)
3369 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
3371 flow_delete_insn (next);
3375 if (bb->end == insn)
3376 bb->end = PREV_INSN (insn);
3377 flow_delete_insn (insn);
3380 /* Delete dead libcalls for propagate_block. Return the insn
3381 before the libcall. */
3384 propagate_block_delete_libcall (bb, insn, note)
3388 rtx first = XEXP (note, 0);
3389 rtx before = PREV_INSN (first);
3391 if (insn == bb->end)
3394 flow_delete_insn_chain (first, insn);
3398 /* Update the life-status of regs for one insn. Return the previous insn. */
3401 propagate_one_insn (pbi, insn)
3402 struct propagate_block_info *pbi;
3405 rtx prev = PREV_INSN (insn);
3406 int flags = pbi->flags;
3407 int insn_is_dead = 0;
3408 int libcall_is_dead = 0;
3412 if (! INSN_P (insn))
3415 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
3416 if (flags & PROP_SCAN_DEAD_CODE)
3418 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0,
3420 libcall_is_dead = (insn_is_dead && note != 0
3421 && libcall_dead_p (pbi, note, insn));
3424 /* We almost certainly don't want to delete prologue or epilogue
3425 instructions. Warn about probable compiler losage. */
3428 && (((HAVE_epilogue || HAVE_prologue)
3429 && prologue_epilogue_contains (insn))
3430 || (HAVE_sibcall_epilogue
3431 && sibcall_epilogue_contains (insn))))
3433 if (flags & PROP_KILL_DEAD_CODE)
3435 warning ("ICE: would have deleted prologue/epilogue insn");
3436 if (!inhibit_warnings)
3439 libcall_is_dead = insn_is_dead = 0;
3442 /* If an instruction consists of just dead store(s) on final pass,
3444 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
3446 /* Record sets. Do this even for dead instructions, since they
3447 would have killed the values if they hadn't been deleted. */
3448 mark_set_regs (pbi, PATTERN (insn), insn);
3450 /* CC0 is now known to be dead. Either this insn used it,
3451 in which case it doesn't anymore, or clobbered it,
3452 so the next insn can't use it. */
3455 if (libcall_is_dead)
3457 prev = propagate_block_delete_libcall (pbi->bb, insn, note);
3458 insn = NEXT_INSN (prev);
3461 propagate_block_delete_insn (pbi->bb, insn);
3466 /* See if this is an increment or decrement that can be merged into
3467 a following memory address. */
3470 register rtx x = single_set (insn);
3472 /* Does this instruction increment or decrement a register? */
3473 if ((flags & PROP_AUTOINC)
3475 && GET_CODE (SET_DEST (x)) == REG
3476 && (GET_CODE (SET_SRC (x)) == PLUS
3477 || GET_CODE (SET_SRC (x)) == MINUS)
3478 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
3479 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
3480 /* Ok, look for a following memory ref we can combine with.
3481 If one is found, change the memory ref to a PRE_INC
3482 or PRE_DEC, cancel this insn, and return 1.
3483 Return 0 if nothing has been done. */
3484 && try_pre_increment_1 (pbi, insn))
3487 #endif /* AUTO_INC_DEC */
3489 CLEAR_REG_SET (pbi->new_set);
3491 /* If this is not the final pass, and this insn is copying the value of
3492 a library call and it's dead, don't scan the insns that perform the
3493 library call, so that the call's arguments are not marked live. */
3494 if (libcall_is_dead)
3496 /* Record the death of the dest reg. */
3497 mark_set_regs (pbi, PATTERN (insn), insn);
3499 insn = XEXP (note, 0);
3500 return PREV_INSN (insn);
3502 else if (GET_CODE (PATTERN (insn)) == SET
3503 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
3504 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
3505 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
3506 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
3507 /* We have an insn to pop a constant amount off the stack.
3508 (Such insns use PLUS regardless of the direction of the stack,
3509 and any insn to adjust the stack by a constant is always a pop.)
3510 These insns, if not dead stores, have no effect on life. */
3514 /* Any regs live at the time of a call instruction must not go
3515 in a register clobbered by calls. Find all regs now live and
3516 record this for them. */
3518 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
3519 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
3520 { REG_N_CALLS_CROSSED (i)++; });
3522 /* Record sets. Do this even for dead instructions, since they
3523 would have killed the values if they hadn't been deleted. */
3524 mark_set_regs (pbi, PATTERN (insn), insn);
3526 if (GET_CODE (insn) == CALL_INSN)
3532 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
3533 cond = COND_EXEC_TEST (PATTERN (insn));
3535 /* Non-constant calls clobber memory. */
3536 if (! CONST_CALL_P (insn))
3537 free_EXPR_LIST_list (&pbi->mem_set_list);
3539 /* There may be extra registers to be clobbered. */
3540 for (note = CALL_INSN_FUNCTION_USAGE (insn);
3542 note = XEXP (note, 1))
3543 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
3544 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
3545 cond, insn, pbi->flags);
3547 /* Calls change all call-used and global registers. */
3548 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3549 if (call_used_regs[i] && ! global_regs[i]
3552 /* We do not want REG_UNUSED notes for these registers. */
3553 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
3555 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
3559 /* If an insn doesn't use CC0, it becomes dead since we assume
3560 that every insn clobbers it. So show it dead here;
3561 mark_used_regs will set it live if it is referenced. */
3566 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
3568 /* Sometimes we may have inserted something before INSN (such as a move)
3569 when we make an auto-inc. So ensure we will scan those insns. */
3571 prev = PREV_INSN (insn);
3574 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
3580 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
3581 cond = COND_EXEC_TEST (PATTERN (insn));
3583 /* Calls use their arguments. */
3584 for (note = CALL_INSN_FUNCTION_USAGE (insn);
3586 note = XEXP (note, 1))
3587 if (GET_CODE (XEXP (note, 0)) == USE)
3588 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
3591 /* The stack ptr is used (honorarily) by a CALL insn. */
3592 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
3594 /* Calls may also reference any of the global registers,
3595 so they are made live. */
3596 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3598 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
3603 /* On final pass, update counts of how many insns in which each reg
3605 if (flags & PROP_REG_INFO)
3606 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
3607 { REG_LIVE_LENGTH (i)++; });
3612 /* Initialize a propagate_block_info struct for public consumption.
3613 Note that the structure itself is opaque to this file, but that
3614 the user can use the regsets provided here. */
3616 struct propagate_block_info *
3617 init_propagate_block_info (bb, live, local_set, flags)
3623 struct propagate_block_info *pbi = xmalloc (sizeof(*pbi));
3626 pbi->reg_live = live;
3627 pbi->mem_set_list = NULL_RTX;
3628 pbi->local_set = local_set;
3632 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
3633 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
3635 pbi->reg_next_use = NULL;
3637 pbi->new_set = BITMAP_XMALLOC ();
3639 #ifdef HAVE_conditional_execution
3640 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
3641 free_reg_cond_life_info);
3642 pbi->reg_cond_reg = BITMAP_XMALLOC ();
3644 /* If this block ends in a conditional branch, for each register live
3645 from one side of the branch and not the other, record the register
3646 as conditionally dead. */
3647 if ((flags & (PROP_DEATH_NOTES | PROP_SCAN_DEAD_CODE))
3648 && GET_CODE (bb->end) == JUMP_INSN
3649 && any_condjump_p (bb->end))
3651 regset_head diff_head;
3652 regset diff = INITIALIZE_REG_SET (diff_head);
3653 basic_block bb_true, bb_false;
3654 rtx cond_true, cond_false, set_src;
3657 /* Identify the successor blocks. */
3658 bb_true = bb->succ->dest;
3659 if (bb->succ->succ_next != NULL)
3661 bb_false = bb->succ->succ_next->dest;
3663 if (bb->succ->flags & EDGE_FALLTHRU)
3665 basic_block t = bb_false;
3669 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
3674 /* This can happen with a conditional jump to the next insn. */
3675 if (JUMP_LABEL (bb->end) != bb_true->head)
3678 /* Simplest way to do nothing. */
3682 /* Extract the condition from the branch. */
3683 set_src = SET_SRC (pc_set (bb->end));
3684 cond_true = XEXP (set_src, 0);
3685 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
3686 GET_MODE (cond_true), XEXP (cond_true, 0),
3687 XEXP (cond_true, 1));
3688 if (GET_CODE (XEXP (set_src, 1)) == PC)
3691 cond_false = cond_true;
3695 /* Compute which register lead different lives in the successors. */
3696 if (bitmap_operation (diff, bb_true->global_live_at_start,
3697 bb_false->global_live_at_start, BITMAP_XOR))
3699 if (GET_CODE (XEXP (cond_true, 0)) != REG)
3701 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond_true, 0)));
3703 /* For each such register, mark it conditionally dead. */
3704 EXECUTE_IF_SET_IN_REG_SET
3707 struct reg_cond_life_info *rcli;
3710 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
3712 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
3716 rcli->condition = alloc_EXPR_LIST (0, cond, NULL_RTX);
3718 splay_tree_insert (pbi->reg_cond_dead, i,
3719 (splay_tree_value) rcli);
3723 FREE_REG_SET (diff);
3727 /* If this block has no successors, any stores to the frame that aren't
3728 used later in the block are dead. So make a pass over the block
3729 recording any such that are made and show them dead at the end. We do
3730 a very conservative and simple job here. */
3731 if ((flags & PROP_SCAN_DEAD_CODE)
3732 && (bb->succ == NULL
3733 || (bb->succ->succ_next == NULL
3734 && bb->succ->dest == EXIT_BLOCK_PTR)))
3737 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
3738 if (GET_CODE (insn) == INSN
3739 && GET_CODE (PATTERN (insn)) == SET
3740 && GET_CODE (SET_DEST (PATTERN (insn))) == MEM)
3742 rtx mem = SET_DEST (PATTERN (insn));
3744 if (XEXP (mem, 0) == frame_pointer_rtx
3745 || (GET_CODE (XEXP (mem, 0)) == PLUS
3746 && XEXP (XEXP (mem, 0), 0) == frame_pointer_rtx
3747 && GET_CODE (XEXP (XEXP (mem, 0), 1)) == CONST_INT))
3748 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
3755 /* Release a propagate_block_info struct. */
3758 free_propagate_block_info (pbi)
3759 struct propagate_block_info *pbi;
3761 free_EXPR_LIST_list (&pbi->mem_set_list);
3763 BITMAP_XFREE (pbi->new_set);
3765 #ifdef HAVE_conditional_execution
3766 splay_tree_delete (pbi->reg_cond_dead);
3767 BITMAP_XFREE (pbi->reg_cond_reg);
3770 if (pbi->reg_next_use)
3771 free (pbi->reg_next_use);
3776 /* Compute the registers live at the beginning of a basic block BB from
3777 those live at the end.
3779 When called, REG_LIVE contains those live at the end. On return, it
3780 contains those live at the beginning.
3782 LOCAL_SET, if non-null, will be set with all registers killed by
3783 this basic block. */
3786 propagate_block (bb, live, local_set, flags)
3792 struct propagate_block_info *pbi;
3795 pbi = init_propagate_block_info (bb, live, local_set, flags);
3797 if (flags & PROP_REG_INFO)
3801 /* Process the regs live at the end of the block.
3802 Mark them as not local to any one basic block. */
3803 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
3804 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
3807 /* Scan the block an insn at a time from end to beginning. */
3809 for (insn = bb->end; ; insn = prev)
3811 /* If this is a call to `setjmp' et al, warn if any
3812 non-volatile datum is live. */
3813 if ((flags & PROP_REG_INFO)
3814 && GET_CODE (insn) == NOTE
3815 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
3816 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
3818 prev = propagate_one_insn (pbi, insn);
3820 if (insn == bb->head)
3824 free_propagate_block_info (pbi);
3827 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
3828 (SET expressions whose destinations are registers dead after the insn).
3829 NEEDED is the regset that says which regs are alive after the insn.
3831 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
3833 If X is the entire body of an insn, NOTES contains the reg notes
3834 pertaining to the insn. */
3837 insn_dead_p (pbi, x, call_ok, notes)
3838 struct propagate_block_info *pbi;
3841 rtx notes ATTRIBUTE_UNUSED;
3843 enum rtx_code code = GET_CODE (x);
3846 /* If flow is invoked after reload, we must take existing AUTO_INC
3847 expresions into account. */
3848 if (reload_completed)
3850 for ( ; notes; notes = XEXP (notes, 1))
3852 if (REG_NOTE_KIND (notes) == REG_INC)
3854 int regno = REGNO (XEXP (notes, 0));
3856 /* Don't delete insns to set global regs. */
3857 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
3858 || REGNO_REG_SET_P (pbi->reg_live, regno))
3865 /* If setting something that's a reg or part of one,
3866 see if that register's altered value will be live. */
3870 rtx r = SET_DEST (x);
3873 if (GET_CODE (r) == CC0)
3874 return ! pbi->cc0_live;
3877 /* A SET that is a subroutine call cannot be dead. */
3878 if (GET_CODE (SET_SRC (x)) == CALL)
3884 /* Don't eliminate loads from volatile memory or volatile asms. */
3885 else if (volatile_refs_p (SET_SRC (x)))
3888 if (GET_CODE (r) == MEM)
3892 if (MEM_VOLATILE_P (r))
3895 /* Walk the set of memory locations we are currently tracking
3896 and see if one is an identical match to this memory location.
3897 If so, this memory write is dead (remember, we're walking
3898 backwards from the end of the block to the start). */
3899 temp = pbi->mem_set_list;
3902 if (rtx_equal_p (XEXP (temp, 0), r))
3904 temp = XEXP (temp, 1);
3909 while (GET_CODE (r) == SUBREG
3910 || GET_CODE (r) == STRICT_LOW_PART
3911 || GET_CODE (r) == ZERO_EXTRACT)
3914 if (GET_CODE (r) == REG)
3916 int regno = REGNO (r);
3919 if (REGNO_REG_SET_P (pbi->reg_live, regno))
3922 /* If this is a hard register, verify that subsequent
3923 words are not needed. */
3924 if (regno < FIRST_PSEUDO_REGISTER)
3926 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
3929 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
3933 /* Don't delete insns to set global regs. */
3934 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
3937 /* Make sure insns to set the stack pointer aren't deleted. */
3938 if (regno == STACK_POINTER_REGNUM)
3941 /* Make sure insns to set the frame pointer aren't deleted. */
3942 if (regno == FRAME_POINTER_REGNUM
3943 && (! reload_completed || frame_pointer_needed))
3945 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3946 if (regno == HARD_FRAME_POINTER_REGNUM
3947 && (! reload_completed || frame_pointer_needed))
3951 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3952 /* Make sure insns to set arg pointer are never deleted
3953 (if the arg pointer isn't fixed, there will be a USE
3954 for it, so we can treat it normally). */
3955 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
3959 #ifdef PIC_OFFSET_TABLE_REGNUM
3960 /* Before reload, do not allow sets of the pic register
3961 to be deleted. Reload can insert references to
3962 constant pool memory anywhere in the function, making
3963 the PIC register live where it wasn't before. */
3964 if (regno == PIC_OFFSET_TABLE_REGNUM && fixed_regs[regno]
3965 && ! reload_completed)
3969 /* Otherwise, the set is dead. */
3975 /* If performing several activities, insn is dead if each activity
3976 is individually dead. Also, CLOBBERs and USEs can be ignored; a
3977 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
3979 else if (code == PARALLEL)
3981 int i = XVECLEN (x, 0);
3983 for (i--; i >= 0; i--)
3984 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
3985 && GET_CODE (XVECEXP (x, 0, i)) != USE
3986 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
3992 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
3993 is not necessarily true for hard registers. */
3994 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
3995 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
3996 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
3999 /* We do not check other CLOBBER or USE here. An insn consisting of just
4000 a CLOBBER or just a USE should not be deleted. */
4004 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
4005 return 1 if the entire library call is dead.
4006 This is true if INSN copies a register (hard or pseudo)
4007 and if the hard return reg of the call insn is dead.
4008 (The caller should have tested the destination of the SET inside
4009 INSN already for death.)
4011 If this insn doesn't just copy a register, then we don't
4012 have an ordinary libcall. In that case, cse could not have
4013 managed to substitute the source for the dest later on,
4014 so we can assume the libcall is dead.
4016 PBI is the block info giving pseudoregs live before this insn.
4017 NOTE is the REG_RETVAL note of the insn. */
4020 libcall_dead_p (pbi, note, insn)
4021 struct propagate_block_info *pbi;
4025 rtx x = single_set (insn);
4029 register rtx r = SET_SRC (x);
4030 if (GET_CODE (r) == REG)
4032 rtx call = XEXP (note, 0);
4036 /* Find the call insn. */
4037 while (call != insn && GET_CODE (call) != CALL_INSN)
4038 call = NEXT_INSN (call);
4040 /* If there is none, do nothing special,
4041 since ordinary death handling can understand these insns. */
4045 /* See if the hard reg holding the value is dead.
4046 If this is a PARALLEL, find the call within it. */
4047 call_pat = PATTERN (call);
4048 if (GET_CODE (call_pat) == PARALLEL)
4050 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
4051 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
4052 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
4055 /* This may be a library call that is returning a value
4056 via invisible pointer. Do nothing special, since
4057 ordinary death handling can understand these insns. */
4061 call_pat = XVECEXP (call_pat, 0, i);
4064 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
4070 /* Return 1 if register REGNO was used before it was set, i.e. if it is
4071 live at function entry. Don't count global register variables, variables
4072 in registers that can be used for function arg passing, or variables in
4073 fixed hard registers. */
4076 regno_uninitialized (regno)
4079 if (n_basic_blocks == 0
4080 || (regno < FIRST_PSEUDO_REGISTER
4081 && (global_regs[regno]
4082 || fixed_regs[regno]
4083 || FUNCTION_ARG_REGNO_P (regno))))
4086 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
4089 /* 1 if register REGNO was alive at a place where `setjmp' was called
4090 and was set more than once or is an argument.
4091 Such regs may be clobbered by `longjmp'. */
4094 regno_clobbered_at_setjmp (regno)
4097 if (n_basic_blocks == 0)
4100 return ((REG_N_SETS (regno) > 1
4101 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
4102 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
4105 /* INSN references memory, possibly using autoincrement addressing modes.
4106 Find any entries on the mem_set_list that need to be invalidated due
4107 to an address change. */
4110 invalidate_mems_from_autoinc (pbi, insn)
4111 struct propagate_block_info *pbi;
4114 rtx note = REG_NOTES (insn);
4115 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
4117 if (REG_NOTE_KIND (note) == REG_INC)
4119 rtx temp = pbi->mem_set_list;
4120 rtx prev = NULL_RTX;
4125 next = XEXP (temp, 1);
4126 if (reg_overlap_mentioned_p (XEXP (note, 0), XEXP (temp, 0)))
4128 /* Splice temp out of list. */
4130 XEXP (prev, 1) = next;
4132 pbi->mem_set_list = next;
4133 free_EXPR_LIST_node (temp);
4143 /* Process the registers that are set within X. Their bits are set to
4144 1 in the regset DEAD, because they are dead prior to this insn.
4146 If INSN is nonzero, it is the insn being processed.
4148 FLAGS is the set of operations to perform. */
4151 mark_set_regs (pbi, x, insn)
4152 struct propagate_block_info *pbi;
4155 rtx cond = NULL_RTX;
4160 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
4162 if (REG_NOTE_KIND (link) == REG_INC)
4163 mark_set_1 (pbi, SET, XEXP (link, 0),
4164 (GET_CODE (x) == COND_EXEC
4165 ? COND_EXEC_TEST (x) : NULL_RTX),
4169 switch (code = GET_CODE (x))
4173 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
4177 cond = COND_EXEC_TEST (x);
4178 x = COND_EXEC_CODE (x);
4184 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
4186 rtx sub = XVECEXP (x, 0, i);
4187 switch (code = GET_CODE (sub))
4190 if (cond != NULL_RTX)
4193 cond = COND_EXEC_TEST (sub);
4194 sub = COND_EXEC_CODE (sub);
4195 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
4201 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
4216 /* Process a single SET rtx, X. */
4219 mark_set_1 (pbi, code, reg, cond, insn, flags)
4220 struct propagate_block_info *pbi;
4222 rtx reg, cond, insn;
4225 int regno_first = -1, regno_last = -1;
4229 /* Some targets place small structures in registers for
4230 return values of functions. We have to detect this
4231 case specially here to get correct flow information. */
4232 if (GET_CODE (reg) == PARALLEL
4233 && GET_MODE (reg) == BLKmode)
4235 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
4236 mark_set_1 (pbi, code, XVECEXP (reg, 0, i), cond, insn, flags);
4240 /* Modifying just one hardware register of a multi-reg value or just a
4241 byte field of a register does not mean the value from before this insn
4242 is now dead. Of course, if it was dead after it's unused now. */
4244 switch (GET_CODE (reg))
4248 case STRICT_LOW_PART:
4249 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
4251 reg = XEXP (reg, 0);
4252 while (GET_CODE (reg) == SUBREG
4253 || GET_CODE (reg) == ZERO_EXTRACT
4254 || GET_CODE (reg) == SIGN_EXTRACT
4255 || GET_CODE (reg) == STRICT_LOW_PART);
4256 if (GET_CODE (reg) == MEM)
4258 not_dead = REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
4262 regno_last = regno_first = REGNO (reg);
4263 if (regno_first < FIRST_PSEUDO_REGISTER)
4264 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
4268 if (GET_CODE (SUBREG_REG (reg)) == REG)
4270 enum machine_mode outer_mode = GET_MODE (reg);
4271 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
4273 /* Identify the range of registers affected. This is moderately
4274 tricky for hard registers. See alter_subreg. */
4276 regno_last = regno_first = REGNO (SUBREG_REG (reg));
4277 if (regno_first < FIRST_PSEUDO_REGISTER)
4279 #ifdef ALTER_HARD_SUBREG
4280 regno_first = ALTER_HARD_SUBREG (outer_mode, SUBREG_WORD (reg),
4281 inner_mode, regno_first);
4283 regno_first += SUBREG_WORD (reg);
4285 regno_last = (regno_first
4286 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
4288 /* Since we've just adjusted the register number ranges, make
4289 sure REG matches. Otherwise some_was_live will be clear
4290 when it shouldn't have been, and we'll create incorrect
4291 REG_UNUSED notes. */
4292 reg = gen_rtx_REG (outer_mode, regno_first);
4296 /* If the number of words in the subreg is less than the number
4297 of words in the full register, we have a well-defined partial
4298 set. Otherwise the high bits are undefined.
4300 This is only really applicable to pseudos, since we just took
4301 care of multi-word hard registers. */
4302 if (((GET_MODE_SIZE (outer_mode)
4303 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
4304 < ((GET_MODE_SIZE (inner_mode)
4305 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
4306 not_dead = REGNO_REG_SET_P (pbi->reg_live, regno_first);
4308 reg = SUBREG_REG (reg);
4312 reg = SUBREG_REG (reg);
4319 /* If this set is a MEM, then it kills any aliased writes.
4320 If this set is a REG, then it kills any MEMs which use the reg. */
4321 if (flags & PROP_SCAN_DEAD_CODE)
4323 if (GET_CODE (reg) == MEM || GET_CODE (reg) == REG)
4325 rtx temp = pbi->mem_set_list;
4326 rtx prev = NULL_RTX;
4331 next = XEXP (temp, 1);
4332 if ((GET_CODE (reg) == MEM
4333 && output_dependence (XEXP (temp, 0), reg))
4334 || (GET_CODE (reg) == REG
4335 && reg_overlap_mentioned_p (reg, XEXP (temp, 0))))
4337 /* Splice this entry out of the list. */
4339 XEXP (prev, 1) = next;
4341 pbi->mem_set_list = next;
4342 free_EXPR_LIST_node (temp);
4350 /* If the memory reference had embedded side effects (autoincrement
4351 address modes. Then we may need to kill some entries on the
4353 if (insn && GET_CODE (reg) == MEM)
4354 invalidate_mems_from_autoinc (pbi, insn);
4356 if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
4357 /* ??? With more effort we could track conditional memory life. */
4359 /* We do not know the size of a BLKmode store, so we do not track
4360 them for redundant store elimination. */
4361 && GET_MODE (reg) != BLKmode
4362 /* There are no REG_INC notes for SP, so we can't assume we'll see
4363 everything that invalidates it. To be safe, don't eliminate any
4364 stores though SP; none of them should be redundant anyway. */
4365 && ! reg_mentioned_p (stack_pointer_rtx, reg))
4366 pbi->mem_set_list = alloc_EXPR_LIST (0, reg, pbi->mem_set_list);
4369 if (GET_CODE (reg) == REG
4370 && ! (regno_first == FRAME_POINTER_REGNUM
4371 && (! reload_completed || frame_pointer_needed))
4372 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4373 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
4374 && (! reload_completed || frame_pointer_needed))
4376 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4377 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
4381 int some_was_live = 0, some_was_dead = 0;
4383 for (i = regno_first; i <= regno_last; ++i)
4385 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
4387 SET_REGNO_REG_SET (pbi->local_set, i);
4388 if (code != CLOBBER)
4389 SET_REGNO_REG_SET (pbi->new_set, i);
4391 some_was_live |= needed_regno;
4392 some_was_dead |= ! needed_regno;
4395 #ifdef HAVE_conditional_execution
4396 /* Consider conditional death in deciding that the register needs
4398 if (some_was_live && ! not_dead
4399 /* The stack pointer is never dead. Well, not strictly true,
4400 but it's very difficult to tell from here. Hopefully
4401 combine_stack_adjustments will fix up the most egregious
4403 && regno_first != STACK_POINTER_REGNUM)
4405 for (i = regno_first; i <= regno_last; ++i)
4406 if (! mark_regno_cond_dead (pbi, i, cond))
4411 /* Additional data to record if this is the final pass. */
4412 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
4413 | PROP_DEATH_NOTES | PROP_AUTOINC))
4416 register int blocknum = pbi->bb->index;
4419 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4421 y = pbi->reg_next_use[regno_first];
4423 /* The next use is no longer next, since a store intervenes. */
4424 for (i = regno_first; i <= regno_last; ++i)
4425 pbi->reg_next_use[i] = 0;
4428 if (flags & PROP_REG_INFO)
4430 for (i = regno_first; i <= regno_last; ++i)
4432 /* Count (weighted) references, stores, etc. This counts a
4433 register twice if it is modified, but that is correct. */
4434 REG_N_SETS (i) += 1;
4435 REG_N_REFS (i) += (optimize_size ? 1
4436 : pbi->bb->loop_depth + 1);
4438 /* The insns where a reg is live are normally counted
4439 elsewhere, but we want the count to include the insn
4440 where the reg is set, and the normal counting mechanism
4441 would not count it. */
4442 REG_LIVE_LENGTH (i) += 1;
4445 /* If this is a hard reg, record this function uses the reg. */
4446 if (regno_first < FIRST_PSEUDO_REGISTER)
4448 for (i = regno_first; i <= regno_last; i++)
4449 regs_ever_live[i] = 1;
4453 /* Keep track of which basic blocks each reg appears in. */
4454 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
4455 REG_BASIC_BLOCK (regno_first) = blocknum;
4456 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
4457 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
4461 if (! some_was_dead)
4463 if (flags & PROP_LOG_LINKS)
4465 /* Make a logical link from the next following insn
4466 that uses this register, back to this insn.
4467 The following insns have already been processed.
4469 We don't build a LOG_LINK for hard registers containing
4470 in ASM_OPERANDs. If these registers get replaced,
4471 we might wind up changing the semantics of the insn,
4472 even if reload can make what appear to be valid
4473 assignments later. */
4474 if (y && (BLOCK_NUM (y) == blocknum)
4475 && (regno_first >= FIRST_PSEUDO_REGISTER
4476 || asm_noperands (PATTERN (y)) < 0))
4477 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
4482 else if (! some_was_live)
4484 if (flags & PROP_REG_INFO)
4485 REG_N_DEATHS (regno_first) += 1;
4487 if (flags & PROP_DEATH_NOTES)
4489 /* Note that dead stores have already been deleted
4490 when possible. If we get here, we have found a
4491 dead store that cannot be eliminated (because the
4492 same insn does something useful). Indicate this
4493 by marking the reg being set as dying here. */
4495 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
4500 if (flags & PROP_DEATH_NOTES)
4502 /* This is a case where we have a multi-word hard register
4503 and some, but not all, of the words of the register are
4504 needed in subsequent insns. Write REG_UNUSED notes
4505 for those parts that were not needed. This case should
4508 for (i = regno_first; i <= regno_last; ++i)
4509 if (! REGNO_REG_SET_P (pbi->reg_live, i))
4511 = alloc_EXPR_LIST (REG_UNUSED,
4512 gen_rtx_REG (reg_raw_mode[i], i),
4518 /* Mark the register as being dead. */
4521 /* The stack pointer is never dead. Well, not strictly true,
4522 but it's very difficult to tell from here. Hopefully
4523 combine_stack_adjustments will fix up the most egregious
4525 && regno_first != STACK_POINTER_REGNUM)
4527 for (i = regno_first; i <= regno_last; ++i)
4528 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
4531 else if (GET_CODE (reg) == REG)
4533 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4534 pbi->reg_next_use[regno_first] = 0;
4537 /* If this is the last pass and this is a SCRATCH, show it will be dying
4538 here and count it. */
4539 else if (GET_CODE (reg) == SCRATCH)
4541 if (flags & PROP_DEATH_NOTES)
4543 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
4547 #ifdef HAVE_conditional_execution
4548 /* Mark REGNO conditionally dead. Return true if the register is
4549 now unconditionally dead. */
4552 mark_regno_cond_dead (pbi, regno, cond)
4553 struct propagate_block_info *pbi;
4557 /* If this is a store to a predicate register, the value of the
4558 predicate is changing, we don't know that the predicate as seen
4559 before is the same as that seen after. Flush all dependent
4560 conditions from reg_cond_dead. This will make all such
4561 conditionally live registers unconditionally live. */
4562 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
4563 flush_reg_cond_reg (pbi, regno);
4565 /* If this is an unconditional store, remove any conditional
4566 life that may have existed. */
4567 if (cond == NULL_RTX)
4568 splay_tree_remove (pbi->reg_cond_dead, regno);
4571 splay_tree_node node;
4572 struct reg_cond_life_info *rcli;
4575 /* Otherwise this is a conditional set. Record that fact.
4576 It may have been conditionally used, or there may be a
4577 subsequent set with a complimentary condition. */
4579 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
4582 /* The register was unconditionally live previously.
4583 Record the current condition as the condition under
4584 which it is dead. */
4585 rcli = (struct reg_cond_life_info *)
4586 xmalloc (sizeof (*rcli));
4587 rcli->condition = alloc_EXPR_LIST (0, cond, NULL_RTX);
4588 splay_tree_insert (pbi->reg_cond_dead, regno,
4589 (splay_tree_value) rcli);
4591 SET_REGNO_REG_SET (pbi->reg_cond_reg,
4592 REGNO (XEXP (cond, 0)));
4594 /* Not unconditionaly dead. */
4599 /* The register was conditionally live previously.
4600 Add the new condition to the old. */
4601 rcli = (struct reg_cond_life_info *) node->value;
4602 ncond = rcli->condition;
4603 ncond = ior_reg_cond (ncond, cond);
4605 /* If the register is now unconditionally dead,
4606 remove the entry in the splay_tree. */
4607 if (ncond == const1_rtx)
4608 splay_tree_remove (pbi->reg_cond_dead, regno);
4611 rcli->condition = ncond;
4613 SET_REGNO_REG_SET (pbi->reg_cond_reg,
4614 REGNO (XEXP (cond, 0)));
4616 /* Not unconditionaly dead. */
4625 /* Called from splay_tree_delete for pbi->reg_cond_life. */
4628 free_reg_cond_life_info (value)
4629 splay_tree_value value;
4631 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
4632 free_EXPR_LIST_list (&rcli->condition);
4636 /* Helper function for flush_reg_cond_reg. */
4639 flush_reg_cond_reg_1 (node, data)
4640 splay_tree_node node;
4643 struct reg_cond_life_info *rcli;
4644 int *xdata = (int *) data;
4645 unsigned int regno = xdata[0];
4648 /* Don't need to search if last flushed value was farther on in
4649 the in-order traversal. */
4650 if (xdata[1] >= (int) node->key)
4653 /* Splice out portions of the expression that refer to regno. */
4654 rcli = (struct reg_cond_life_info *) node->value;
4655 c = *(prev = &rcli->condition);
4658 if (regno == REGNO (XEXP (XEXP (c, 0), 0)))
4660 rtx next = XEXP (c, 1);
4661 free_EXPR_LIST_node (c);
4665 c = *(prev = &XEXP (c, 1));
4668 /* If the entire condition is now NULL, signal the node to be removed. */
4669 if (! rcli->condition)
4671 xdata[1] = node->key;
4678 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
4681 flush_reg_cond_reg (pbi, regno)
4682 struct propagate_block_info *pbi;
4689 while (splay_tree_foreach (pbi->reg_cond_dead,
4690 flush_reg_cond_reg_1, pair) == -1)
4691 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
4693 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
4696 /* Logical arithmetic on predicate conditions. IOR, NOT and NAND.
4697 We actually use EXPR_LIST to chain the sub-expressions together
4698 instead of IOR because it's easier to manipulate and we have
4699 the lists.c functions to reuse nodes.
4701 Return a new rtl expression as appropriate. */
4704 ior_reg_cond (old, x)
4707 enum rtx_code x_code;
4711 /* We expect these conditions to be of the form (eq reg 0). */
4712 x_code = GET_CODE (x);
4713 if (GET_RTX_CLASS (x_code) != '<'
4714 || GET_CODE (x_reg = XEXP (x, 0)) != REG
4715 || XEXP (x, 1) != const0_rtx)
4718 /* Search the expression for an existing sub-expression of X_REG. */
4719 for (c = old; c ; c = XEXP (c, 1))
4721 rtx y = XEXP (c, 0);
4722 if (REGNO (XEXP (y, 0)) == REGNO (x_reg))
4724 /* If we find X already present in OLD, we need do nothing. */
4725 if (GET_CODE (y) == x_code)
4728 /* If we find X being a compliment of a condition in OLD,
4729 then the entire condition is true. */
4730 if (GET_CODE (y) == reverse_condition (x_code))
4735 /* Otherwise just add to the chain. */
4736 return alloc_EXPR_LIST (0, x, old);
4743 enum rtx_code x_code;
4746 /* We expect these conditions to be of the form (eq reg 0). */
4747 x_code = GET_CODE (x);
4748 if (GET_RTX_CLASS (x_code) != '<'
4749 || GET_CODE (x_reg = XEXP (x, 0)) != REG
4750 || XEXP (x, 1) != const0_rtx)
4753 return alloc_EXPR_LIST (0, gen_rtx_fmt_ee (reverse_condition (x_code),
4754 VOIDmode, x_reg, const0_rtx),
4759 nand_reg_cond (old, x)
4762 enum rtx_code x_code;
4766 /* We expect these conditions to be of the form (eq reg 0). */
4767 x_code = GET_CODE (x);
4768 if (GET_RTX_CLASS (x_code) != '<'
4769 || GET_CODE (x_reg = XEXP (x, 0)) != REG
4770 || XEXP (x, 1) != const0_rtx)
4773 /* Search the expression for an existing sub-expression of X_REG. */
4775 for (c = *(prev = &old); c ; c = *(prev = &XEXP (c, 1)))
4777 rtx y = XEXP (c, 0);
4778 if (REGNO (XEXP (y, 0)) == REGNO (x_reg))
4780 /* If we find X already present in OLD, then we need to
4782 if (GET_CODE (y) == x_code)
4784 *prev = XEXP (c, 1);
4785 free_EXPR_LIST_node (c);
4786 return old ? old : const0_rtx;
4789 /* If we find X being a compliment of a condition in OLD,
4790 then we need do nothing. */
4791 if (GET_CODE (y) == reverse_condition (x_code))
4796 /* Otherwise, by implication, the register in question is now live for
4797 the inverse of the condition X. */
4798 return alloc_EXPR_LIST (0, gen_rtx_fmt_ee (reverse_condition (x_code),
4799 VOIDmode, x_reg, const0_rtx),
4802 #endif /* HAVE_conditional_execution */
4806 /* Try to substitute the auto-inc expression INC as the address inside
4807 MEM which occurs in INSN. Currently, the address of MEM is an expression
4808 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
4809 that has a single set whose source is a PLUS of INCR_REG and something
4813 attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
4814 struct propagate_block_info *pbi;
4815 rtx inc, insn, mem, incr, incr_reg;
4817 int regno = REGNO (incr_reg);
4818 rtx set = single_set (incr);
4819 rtx q = SET_DEST (set);
4820 rtx y = SET_SRC (set);
4821 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
4823 /* Make sure this reg appears only once in this insn. */
4824 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
4827 if (dead_or_set_p (incr, incr_reg)
4828 /* Mustn't autoinc an eliminable register. */
4829 && (regno >= FIRST_PSEUDO_REGISTER
4830 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
4832 /* This is the simple case. Try to make the auto-inc. If
4833 we can't, we are done. Otherwise, we will do any
4834 needed updates below. */
4835 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
4838 else if (GET_CODE (q) == REG
4839 /* PREV_INSN used here to check the semi-open interval
4841 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
4842 /* We must also check for sets of q as q may be
4843 a call clobbered hard register and there may
4844 be a call between PREV_INSN (insn) and incr. */
4845 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
4847 /* We have *p followed sometime later by q = p+size.
4848 Both p and q must be live afterward,
4849 and q is not used between INSN and its assignment.
4850 Change it to q = p, ...*q..., q = q+size.
4851 Then fall into the usual case. */
4856 emit_move_insn (q, incr_reg);
4857 insns = get_insns ();
4860 if (basic_block_for_insn)
4861 for (temp = insns; temp; temp = NEXT_INSN (temp))
4862 set_block_for_insn (temp, pbi->bb);
4864 /* If we can't make the auto-inc, or can't make the
4865 replacement into Y, exit. There's no point in making
4866 the change below if we can't do the auto-inc and doing
4867 so is not correct in the pre-inc case. */
4870 validate_change (insn, &XEXP (mem, 0), inc, 1);
4871 validate_change (incr, &XEXP (y, opnum), q, 1);
4872 if (! apply_change_group ())
4875 /* We now know we'll be doing this change, so emit the
4876 new insn(s) and do the updates. */
4877 emit_insns_before (insns, insn);
4879 if (pbi->bb->head == insn)
4880 pbi->bb->head = insns;
4882 /* INCR will become a NOTE and INSN won't contain a
4883 use of INCR_REG. If a use of INCR_REG was just placed in
4884 the insn before INSN, make that the next use.
4885 Otherwise, invalidate it. */
4886 if (GET_CODE (PREV_INSN (insn)) == INSN
4887 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
4888 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
4889 pbi->reg_next_use[regno] = PREV_INSN (insn);
4891 pbi->reg_next_use[regno] = 0;
4896 /* REGNO is now used in INCR which is below INSN, but
4897 it previously wasn't live here. If we don't mark
4898 it as live, we'll put a REG_DEAD note for it
4899 on this insn, which is incorrect. */
4900 SET_REGNO_REG_SET (pbi->reg_live, regno);
4902 /* If there are any calls between INSN and INCR, show
4903 that REGNO now crosses them. */
4904 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
4905 if (GET_CODE (temp) == CALL_INSN)
4906 REG_N_CALLS_CROSSED (regno)++;
4911 /* If we haven't returned, it means we were able to make the
4912 auto-inc, so update the status. First, record that this insn
4913 has an implicit side effect. */
4916 = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
4918 /* Modify the old increment-insn to simply copy
4919 the already-incremented value of our register. */
4920 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
4923 /* If that makes it a no-op (copying the register into itself) delete
4924 it so it won't appear to be a "use" and a "set" of this
4926 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
4928 /* If the original source was dead, it's dead now. */
4931 while (note = find_reg_note (incr, REG_DEAD, NULL_RTX))
4933 remove_note (incr, note);
4934 if (XEXP (note, 0) != incr_reg)
4935 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
4938 PUT_CODE (incr, NOTE);
4939 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
4940 NOTE_SOURCE_FILE (incr) = 0;
4943 if (regno >= FIRST_PSEUDO_REGISTER)
4945 /* Count an extra reference to the reg. When a reg is
4946 incremented, spilling it is worse, so we want to make
4947 that less likely. */
4948 REG_N_REFS (regno) += (optimize_size ? 1 : pbi->bb->loop_depth + 1);
4950 /* Count the increment as a setting of the register,
4951 even though it isn't a SET in rtl. */
4952 REG_N_SETS (regno)++;
4956 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
4960 find_auto_inc (pbi, x, insn)
4961 struct propagate_block_info *pbi;
4965 rtx addr = XEXP (x, 0);
4966 HOST_WIDE_INT offset = 0;
4967 rtx set, y, incr, inc_val;
4969 int size = GET_MODE_SIZE (GET_MODE (x));
4971 if (GET_CODE (insn) == JUMP_INSN)
4974 /* Here we detect use of an index register which might be good for
4975 postincrement, postdecrement, preincrement, or predecrement. */
4977 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
4978 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
4980 if (GET_CODE (addr) != REG)
4983 regno = REGNO (addr);
4985 /* Is the next use an increment that might make auto-increment? */
4986 incr = pbi->reg_next_use[regno];
4987 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
4989 set = single_set (incr);
4990 if (set == 0 || GET_CODE (set) != SET)
4994 if (GET_CODE (y) != PLUS)
4997 if (REGNO (XEXP (y, 0)) == REGNO (addr))
4998 inc_val = XEXP (y, 1);
4999 else if (REGNO (XEXP (y, 1)) == REGNO (addr))
5000 inc_val = XEXP (y, 0);
5004 if (GET_CODE (inc_val) == CONST_INT)
5006 if (HAVE_POST_INCREMENT
5007 && (INTVAL (inc_val) == size && offset == 0))
5008 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
5010 else if (HAVE_POST_DECREMENT
5011 && (INTVAL (inc_val) == - size && offset == 0))
5012 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
5014 else if (HAVE_PRE_INCREMENT
5015 && (INTVAL (inc_val) == size && offset == size))
5016 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
5018 else if (HAVE_PRE_DECREMENT
5019 && (INTVAL (inc_val) == - size && offset == - size))
5020 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
5022 else if (HAVE_POST_MODIFY_DISP && offset == 0)
5023 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
5024 gen_rtx_PLUS (Pmode,
5027 insn, x, incr, addr);
5029 else if (GET_CODE (inc_val) == REG
5030 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
5034 if (HAVE_POST_MODIFY_REG && offset == 0)
5035 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
5036 gen_rtx_PLUS (Pmode,
5039 insn, x, incr, addr);
5043 #endif /* AUTO_INC_DEC */
5046 mark_used_reg (pbi, reg, cond, insn)
5047 struct propagate_block_info *pbi;
5049 rtx cond ATTRIBUTE_UNUSED;
5052 int regno = REGNO (reg);
5053 int some_was_live = REGNO_REG_SET_P (pbi->reg_live, regno);
5054 int some_was_dead = ! some_was_live;
5058 /* A hard reg in a wide mode may really be multiple registers.
5059 If so, mark all of them just like the first. */
5060 if (regno < FIRST_PSEUDO_REGISTER)
5062 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5065 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, regno + n);
5066 some_was_live |= needed_regno;
5067 some_was_dead |= ! needed_regno;
5071 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
5073 /* Record where each reg is used, so when the reg is set we know
5074 the next insn that uses it. */
5075 pbi->reg_next_use[regno] = insn;
5078 if (pbi->flags & PROP_REG_INFO)
5080 if (regno < FIRST_PSEUDO_REGISTER)
5082 /* If this is a register we are going to try to eliminate,
5083 don't mark it live here. If we are successful in
5084 eliminating it, it need not be live unless it is used for
5085 pseudos, in which case it will have been set live when it
5086 was allocated to the pseudos. If the register will not
5087 be eliminated, reload will set it live at that point.
5089 Otherwise, record that this function uses this register. */
5090 /* ??? The PPC backend tries to "eliminate" on the pic
5091 register to itself. This should be fixed. In the mean
5092 time, hack around it. */
5094 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno)
5095 && (regno == FRAME_POINTER_REGNUM
5096 || regno == ARG_POINTER_REGNUM)))
5098 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5100 regs_ever_live[regno + --n] = 1;
5106 /* Keep track of which basic block each reg appears in. */
5108 register int blocknum = pbi->bb->index;
5109 if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN)
5110 REG_BASIC_BLOCK (regno) = blocknum;
5111 else if (REG_BASIC_BLOCK (regno) != blocknum)
5112 REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL;
5114 /* Count (weighted) number of uses of each reg. */
5115 REG_N_REFS (regno) += (optimize_size ? 1
5116 : pbi->bb->loop_depth + 1);
5120 /* Find out if any of the register was set this insn. */
5121 some_not_set = ! REGNO_REG_SET_P (pbi->new_set, regno);
5122 if (regno < FIRST_PSEUDO_REGISTER)
5124 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5126 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, regno + n);
5129 /* Record and count the insns in which a reg dies. If it is used in
5130 this insn and was dead below the insn then it dies in this insn.
5131 If it was set in this insn, we do not make a REG_DEAD note;
5132 likewise if we already made such a note. */
5133 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
5137 /* Check for the case where the register dying partially
5138 overlaps the register set by this insn. */
5139 if (regno < FIRST_PSEUDO_REGISTER
5140 && HARD_REGNO_NREGS (regno, GET_MODE (reg)) > 1)
5142 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5144 some_was_live |= REGNO_REG_SET_P (pbi->new_set, regno + n);
5147 /* If none of the words in X is needed, make a REG_DEAD note.
5148 Otherwise, we must make partial REG_DEAD notes. */
5149 if (! some_was_live)
5151 if ((pbi->flags & PROP_DEATH_NOTES)
5152 && ! find_regno_note (insn, REG_DEAD, regno))
5154 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
5156 if (pbi->flags & PROP_REG_INFO)
5157 REG_N_DEATHS (regno)++;
5161 /* Don't make a REG_DEAD note for a part of a register
5162 that is set in the insn. */
5164 n = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)) - 1;
5165 for (; n >= regno; n--)
5166 if (! REGNO_REG_SET_P (pbi->reg_live, n)
5167 && ! dead_or_set_regno_p (insn, n))
5169 = alloc_EXPR_LIST (REG_DEAD,
5170 gen_rtx_REG (reg_raw_mode[n], n),
5175 SET_REGNO_REG_SET (pbi->reg_live, regno);
5176 if (regno < FIRST_PSEUDO_REGISTER)
5178 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5180 SET_REGNO_REG_SET (pbi->reg_live, regno + n);
5183 #ifdef HAVE_conditional_execution
5184 /* If this is a conditional use, record that fact. If it is later
5185 conditionally set, we'll know to kill the register. */
5186 if (cond != NULL_RTX)
5188 splay_tree_node node;
5189 struct reg_cond_life_info *rcli;
5194 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
5197 /* The register was unconditionally live previously.
5198 No need to do anything. */
5202 /* The register was conditionally live previously.
5203 Subtract the new life cond from the old death cond. */
5204 rcli = (struct reg_cond_life_info *) node->value;
5205 ncond = rcli->condition;
5206 ncond = nand_reg_cond (ncond, cond);
5208 /* If the register is now unconditionally live, remove the
5209 entry in the splay_tree. */
5210 if (ncond == const0_rtx)
5212 rcli->condition = NULL_RTX;
5213 splay_tree_remove (pbi->reg_cond_dead, regno);
5216 rcli->condition = ncond;
5221 /* The register was not previously live at all. Record
5222 the condition under which it is still dead. */
5223 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
5224 rcli->condition = not_reg_cond (cond);
5225 splay_tree_insert (pbi->reg_cond_dead, regno,
5226 (splay_tree_value) rcli);
5229 else if (some_was_live)
5231 splay_tree_node node;
5232 struct reg_cond_life_info *rcli;
5234 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
5237 /* The register was conditionally live previously, but is now
5238 unconditionally so. Remove it from the conditionally dead
5239 list, so that a conditional set won't cause us to think
5241 rcli = (struct reg_cond_life_info *) node->value;
5242 rcli->condition = NULL_RTX;
5243 splay_tree_remove (pbi->reg_cond_dead, regno);
5250 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
5251 This is done assuming the registers needed from X are those that
5252 have 1-bits in PBI->REG_LIVE.
5254 INSN is the containing instruction. If INSN is dead, this function
5258 mark_used_regs (pbi, x, cond, insn)
5259 struct propagate_block_info *pbi;
5262 register RTX_CODE code;
5264 int flags = pbi->flags;
5267 code = GET_CODE (x);
5287 /* If we are clobbering a MEM, mark any registers inside the address
5289 if (GET_CODE (XEXP (x, 0)) == MEM)
5290 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
5294 /* Don't bother watching stores to mems if this is not the
5295 final pass. We'll not be deleting dead stores this round. */
5296 if (flags & PROP_SCAN_DEAD_CODE)
5298 /* Invalidate the data for the last MEM stored, but only if MEM is
5299 something that can be stored into. */
5300 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
5301 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
5302 ; /* needn't clear the memory set list */
5305 rtx temp = pbi->mem_set_list;
5306 rtx prev = NULL_RTX;
5311 next = XEXP (temp, 1);
5312 if (anti_dependence (XEXP (temp, 0), x))
5314 /* Splice temp out of the list. */
5316 XEXP (prev, 1) = next;
5318 pbi->mem_set_list = next;
5319 free_EXPR_LIST_node (temp);
5327 /* If the memory reference had embedded side effects (autoincrement
5328 address modes. Then we may need to kill some entries on the
5331 invalidate_mems_from_autoinc (pbi, insn);
5335 if (flags & PROP_AUTOINC)
5336 find_auto_inc (pbi, x, insn);
5341 #ifdef CLASS_CANNOT_CHANGE_MODE
5342 if (GET_CODE (SUBREG_REG (x)) == REG
5343 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
5344 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
5345 GET_MODE (SUBREG_REG (x))))
5346 REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
5349 /* While we're here, optimize this case. */
5351 if (GET_CODE (x) != REG)
5356 /* See a register other than being set => mark it as needed. */
5357 mark_used_reg (pbi, x, cond, insn);
5362 register rtx testreg = SET_DEST (x);
5365 /* If storing into MEM, don't show it as being used. But do
5366 show the address as being used. */
5367 if (GET_CODE (testreg) == MEM)
5370 if (flags & PROP_AUTOINC)
5371 find_auto_inc (pbi, testreg, insn);
5373 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
5374 mark_used_regs (pbi, SET_SRC (x), cond, insn);
5378 /* Storing in STRICT_LOW_PART is like storing in a reg
5379 in that this SET might be dead, so ignore it in TESTREG.
5380 but in some other ways it is like using the reg.
5382 Storing in a SUBREG or a bit field is like storing the entire
5383 register in that if the register's value is not used
5384 then this SET is not needed. */
5385 while (GET_CODE (testreg) == STRICT_LOW_PART
5386 || GET_CODE (testreg) == ZERO_EXTRACT
5387 || GET_CODE (testreg) == SIGN_EXTRACT
5388 || GET_CODE (testreg) == SUBREG)
5390 #ifdef CLASS_CANNOT_CHANGE_MODE
5391 if (GET_CODE (testreg) == SUBREG
5392 && GET_CODE (SUBREG_REG (testreg)) == REG
5393 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
5394 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
5395 GET_MODE (testreg)))
5396 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
5399 /* Modifying a single register in an alternate mode
5400 does not use any of the old value. But these other
5401 ways of storing in a register do use the old value. */
5402 if (GET_CODE (testreg) == SUBREG
5403 && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
5408 testreg = XEXP (testreg, 0);
5411 /* If this is a store into a register, recursively scan the
5412 value being stored. */
5414 if ((GET_CODE (testreg) == PARALLEL
5415 && GET_MODE (testreg) == BLKmode)
5416 || (GET_CODE (testreg) == REG
5417 && (regno = REGNO (testreg),
5418 ! (regno == FRAME_POINTER_REGNUM
5419 && (! reload_completed || frame_pointer_needed)))
5420 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
5421 && ! (regno == HARD_FRAME_POINTER_REGNUM
5422 && (! reload_completed || frame_pointer_needed))
5424 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
5425 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
5430 mark_used_regs (pbi, SET_DEST (x), cond, insn);
5431 mark_used_regs (pbi, SET_SRC (x), cond, insn);
5438 case UNSPEC_VOLATILE:
5442 /* Traditional and volatile asm instructions must be considered to use
5443 and clobber all hard registers, all pseudo-registers and all of
5444 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
5446 Consider for instance a volatile asm that changes the fpu rounding
5447 mode. An insn should not be moved across this even if it only uses
5448 pseudo-regs because it might give an incorrectly rounded result.
5450 ?!? Unfortunately, marking all hard registers as live causes massive
5451 problems for the register allocator and marking all pseudos as live
5452 creates mountains of uninitialized variable warnings.
5454 So for now, just clear the memory set list and mark any regs
5455 we can find in ASM_OPERANDS as used. */
5456 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
5457 free_EXPR_LIST_list (&pbi->mem_set_list);
5459 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
5460 We can not just fall through here since then we would be confused
5461 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
5462 traditional asms unlike their normal usage. */
5463 if (code == ASM_OPERANDS)
5467 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
5468 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
5474 if (cond != NULL_RTX)
5477 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
5479 cond = COND_EXEC_TEST (x);
5480 x = COND_EXEC_CODE (x);
5484 /* We _do_not_ want to scan operands of phi nodes. Operands of
5485 a phi function are evaluated only when control reaches this
5486 block along a particular edge. Therefore, regs that appear
5487 as arguments to phi should not be added to the global live at
5495 /* Recursively scan the operands of this expression. */
5498 register const char *fmt = GET_RTX_FORMAT (code);
5501 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5505 /* Tail recursive case: save a function call level. */
5511 mark_used_regs (pbi, XEXP (x, i), cond, insn);
5513 else if (fmt[i] == 'E')
5516 for (j = 0; j < XVECLEN (x, i); j++)
5517 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
5526 try_pre_increment_1 (pbi, insn)
5527 struct propagate_block_info *pbi;
5530 /* Find the next use of this reg. If in same basic block,
5531 make it do pre-increment or pre-decrement if appropriate. */
5532 rtx x = single_set (insn);
5533 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
5534 * INTVAL (XEXP (SET_SRC (x), 1)));
5535 int regno = REGNO (SET_DEST (x));
5536 rtx y = pbi->reg_next_use[regno];
5538 && BLOCK_NUM (y) == BLOCK_NUM (insn)
5539 /* Don't do this if the reg dies, or gets set in y; a standard addressing
5540 mode would be better. */
5541 && ! dead_or_set_p (y, SET_DEST (x))
5542 && try_pre_increment (y, SET_DEST (x), amount))
5544 /* We have found a suitable auto-increment
5545 and already changed insn Y to do it.
5546 So flush this increment-instruction. */
5547 PUT_CODE (insn, NOTE);
5548 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
5549 NOTE_SOURCE_FILE (insn) = 0;
5550 /* Count a reference to this reg for the increment
5551 insn we are deleting. When a reg is incremented.
5552 spilling it is worse, so we want to make that
5554 if (regno >= FIRST_PSEUDO_REGISTER)
5556 REG_N_REFS (regno) += (optimize_size ? 1
5557 : pbi->bb->loop_depth + 1);
5558 REG_N_SETS (regno)++;
5565 /* Try to change INSN so that it does pre-increment or pre-decrement
5566 addressing on register REG in order to add AMOUNT to REG.
5567 AMOUNT is negative for pre-decrement.
5568 Returns 1 if the change could be made.
5569 This checks all about the validity of the result of modifying INSN. */
5572 try_pre_increment (insn, reg, amount)
5574 HOST_WIDE_INT amount;
5578 /* Nonzero if we can try to make a pre-increment or pre-decrement.
5579 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
5581 /* Nonzero if we can try to make a post-increment or post-decrement.
5582 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
5583 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
5584 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
5587 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
5590 /* From the sign of increment, see which possibilities are conceivable
5591 on this target machine. */
5592 if (HAVE_PRE_INCREMENT && amount > 0)
5594 if (HAVE_POST_INCREMENT && amount > 0)
5597 if (HAVE_PRE_DECREMENT && amount < 0)
5599 if (HAVE_POST_DECREMENT && amount < 0)
5602 if (! (pre_ok || post_ok))
5605 /* It is not safe to add a side effect to a jump insn
5606 because if the incremented register is spilled and must be reloaded
5607 there would be no way to store the incremented value back in memory. */
5609 if (GET_CODE (insn) == JUMP_INSN)
5614 use = find_use_as_address (PATTERN (insn), reg, 0);
5615 if (post_ok && (use == 0 || use == (rtx) 1))
5617 use = find_use_as_address (PATTERN (insn), reg, -amount);
5621 if (use == 0 || use == (rtx) 1)
5624 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
5627 /* See if this combination of instruction and addressing mode exists. */
5628 if (! validate_change (insn, &XEXP (use, 0),
5629 gen_rtx_fmt_e (amount > 0
5630 ? (do_post ? POST_INC : PRE_INC)
5631 : (do_post ? POST_DEC : PRE_DEC),
5635 /* Record that this insn now has an implicit side effect on X. */
5636 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
5640 #endif /* AUTO_INC_DEC */
5642 /* Find the place in the rtx X where REG is used as a memory address.
5643 Return the MEM rtx that so uses it.
5644 If PLUSCONST is nonzero, search instead for a memory address equivalent to
5645 (plus REG (const_int PLUSCONST)).
5647 If such an address does not appear, return 0.
5648 If REG appears more than once, or is used other than in such an address,
5652 find_use_as_address (x, reg, plusconst)
5655 HOST_WIDE_INT plusconst;
5657 enum rtx_code code = GET_CODE (x);
5658 const char *fmt = GET_RTX_FORMAT (code);
5660 register rtx value = 0;
5663 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
5666 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
5667 && XEXP (XEXP (x, 0), 0) == reg
5668 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
5669 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
5672 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
5674 /* If REG occurs inside a MEM used in a bit-field reference,
5675 that is unacceptable. */
5676 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
5677 return (rtx) (HOST_WIDE_INT) 1;
5681 return (rtx) (HOST_WIDE_INT) 1;
5683 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5687 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
5691 return (rtx) (HOST_WIDE_INT) 1;
5693 else if (fmt[i] == 'E')
5696 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
5698 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
5702 return (rtx) (HOST_WIDE_INT) 1;
5710 /* Write information about registers and basic blocks into FILE.
5711 This is part of making a debugging dump. */
5714 dump_regset (r, outf)
5721 fputs (" (nil)", outf);
5725 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
5727 fprintf (outf, " %d", i);
5728 if (i < FIRST_PSEUDO_REGISTER)
5729 fprintf (outf, " [%s]",
5738 dump_regset (r, stderr);
5739 putc ('\n', stderr);
5743 dump_flow_info (file)
5747 static const char * const reg_class_names[] = REG_CLASS_NAMES;
5749 fprintf (file, "%d registers.\n", max_regno);
5750 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
5753 enum reg_class class, altclass;
5754 fprintf (file, "\nRegister %d used %d times across %d insns",
5755 i, REG_N_REFS (i), REG_LIVE_LENGTH (i));
5756 if (REG_BASIC_BLOCK (i) >= 0)
5757 fprintf (file, " in block %d", REG_BASIC_BLOCK (i));
5759 fprintf (file, "; set %d time%s", REG_N_SETS (i),
5760 (REG_N_SETS (i) == 1) ? "" : "s");
5761 if (REG_USERVAR_P (regno_reg_rtx[i]))
5762 fprintf (file, "; user var");
5763 if (REG_N_DEATHS (i) != 1)
5764 fprintf (file, "; dies in %d places", REG_N_DEATHS (i));
5765 if (REG_N_CALLS_CROSSED (i) == 1)
5766 fprintf (file, "; crosses 1 call");
5767 else if (REG_N_CALLS_CROSSED (i))
5768 fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i));
5769 if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
5770 fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
5771 class = reg_preferred_class (i);
5772 altclass = reg_alternate_class (i);
5773 if (class != GENERAL_REGS || altclass != ALL_REGS)
5775 if (altclass == ALL_REGS || class == ALL_REGS)
5776 fprintf (file, "; pref %s", reg_class_names[(int) class]);
5777 else if (altclass == NO_REGS)
5778 fprintf (file, "; %s or none", reg_class_names[(int) class]);
5780 fprintf (file, "; pref %s, else %s",
5781 reg_class_names[(int) class],
5782 reg_class_names[(int) altclass]);
5784 if (REGNO_POINTER_FLAG (i))
5785 fprintf (file, "; pointer");
5786 fprintf (file, ".\n");
5789 fprintf (file, "\n%d basic blocks, %d edges.\n", n_basic_blocks, n_edges);
5790 for (i = 0; i < n_basic_blocks; i++)
5792 register basic_block bb = BASIC_BLOCK (i);
5795 fprintf (file, "\nBasic block %d: first insn %d, last %d, loop_depth %d, count %d.\n",
5796 i, INSN_UID (bb->head), INSN_UID (bb->end), bb->loop_depth, bb->count);
5798 fprintf (file, "Predecessors: ");
5799 for (e = bb->pred; e ; e = e->pred_next)
5800 dump_edge_info (file, e, 0);
5802 fprintf (file, "\nSuccessors: ");
5803 for (e = bb->succ; e ; e = e->succ_next)
5804 dump_edge_info (file, e, 1);
5806 fprintf (file, "\nRegisters live at start:");
5807 dump_regset (bb->global_live_at_start, file);
5809 fprintf (file, "\nRegisters live at end:");
5810 dump_regset (bb->global_live_at_end, file);
5821 dump_flow_info (stderr);
5825 dump_edge_info (file, e, do_succ)
5830 basic_block side = (do_succ ? e->dest : e->src);
5832 if (side == ENTRY_BLOCK_PTR)
5833 fputs (" ENTRY", file);
5834 else if (side == EXIT_BLOCK_PTR)
5835 fputs (" EXIT", file);
5837 fprintf (file, " %d", side->index);
5840 fprintf (file, " count:%d", e->count);
5844 static const char * const bitnames[] = {
5845 "fallthru", "crit", "ab", "abcall", "eh", "fake"
5848 int i, flags = e->flags;
5852 for (i = 0; flags; i++)
5853 if (flags & (1 << i))
5859 if (i < (int)(sizeof (bitnames) / sizeof (*bitnames)))
5860 fputs (bitnames[i], file);
5862 fprintf (file, "%d", i);
5870 /* Print out one basic block with live information at start and end. */
5880 fprintf (outf, ";; Basic block %d, loop depth %d, count %d",
5881 bb->index, bb->loop_depth, bb->count);
5882 if (bb->eh_beg != -1 || bb->eh_end != -1)
5883 fprintf (outf, ", eh regions %d/%d", bb->eh_beg, bb->eh_end);
5886 fputs (";; Predecessors: ", outf);
5887 for (e = bb->pred; e ; e = e->pred_next)
5888 dump_edge_info (outf, e, 0);
5891 fputs (";; Registers live at start:", outf);
5892 dump_regset (bb->global_live_at_start, outf);
5895 for (insn = bb->head, last = NEXT_INSN (bb->end);
5897 insn = NEXT_INSN (insn))
5898 print_rtl_single (outf, insn);
5900 fputs (";; Registers live at end:", outf);
5901 dump_regset (bb->global_live_at_end, outf);
5904 fputs (";; Successors: ", outf);
5905 for (e = bb->succ; e; e = e->succ_next)
5906 dump_edge_info (outf, e, 1);
5914 dump_bb (bb, stderr);
5921 dump_bb (BASIC_BLOCK(n), stderr);
5924 /* Like print_rtl, but also print out live information for the start of each
5928 print_rtl_with_bb (outf, rtx_first)
5932 register rtx tmp_rtx;
5935 fprintf (outf, "(nil)\n");
5939 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
5940 int max_uid = get_max_uid ();
5941 basic_block *start = (basic_block *)
5942 xcalloc (max_uid, sizeof (basic_block));
5943 basic_block *end = (basic_block *)
5944 xcalloc (max_uid, sizeof (basic_block));
5945 enum bb_state *in_bb_p = (enum bb_state *)
5946 xcalloc (max_uid, sizeof (enum bb_state));
5948 for (i = n_basic_blocks - 1; i >= 0; i--)
5950 basic_block bb = BASIC_BLOCK (i);
5953 start[INSN_UID (bb->head)] = bb;
5954 end[INSN_UID (bb->end)] = bb;
5955 for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x))
5957 enum bb_state state = IN_MULTIPLE_BB;
5958 if (in_bb_p[INSN_UID(x)] == NOT_IN_BB)
5960 in_bb_p[INSN_UID(x)] = state;
5967 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
5972 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
5974 fprintf (outf, ";; Start of basic block %d, registers live:",
5976 dump_regset (bb->global_live_at_start, outf);
5980 if (in_bb_p[INSN_UID(tmp_rtx)] == NOT_IN_BB
5981 && GET_CODE (tmp_rtx) != NOTE
5982 && GET_CODE (tmp_rtx) != BARRIER)
5983 fprintf (outf, ";; Insn is not within a basic block\n");
5984 else if (in_bb_p[INSN_UID(tmp_rtx)] == IN_MULTIPLE_BB)
5985 fprintf (outf, ";; Insn is in multiple basic blocks\n");
5987 did_output = print_rtl_single (outf, tmp_rtx);
5989 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
5991 fprintf (outf, ";; End of basic block %d, registers live:\n",
5993 dump_regset (bb->global_live_at_end, outf);
6006 if (current_function_epilogue_delay_list != 0)
6008 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
6009 for (tmp_rtx = current_function_epilogue_delay_list; tmp_rtx != 0;
6010 tmp_rtx = XEXP (tmp_rtx, 1))
6011 print_rtl_single (outf, XEXP (tmp_rtx, 0));
6015 /* Compute dominator relationships using new flow graph structures. */
6017 compute_flow_dominators (dominators, post_dominators)
6018 sbitmap *dominators;
6019 sbitmap *post_dominators;
6022 sbitmap *temp_bitmap;
6024 basic_block *worklist, *workend, *qin, *qout;
6027 /* Allocate a worklist array/queue. Entries are only added to the
6028 list if they were not already on the list. So the size is
6029 bounded by the number of basic blocks. */
6030 worklist = (basic_block *) xmalloc (sizeof (basic_block) * n_basic_blocks);
6031 workend = &worklist[n_basic_blocks];
6033 temp_bitmap = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
6034 sbitmap_vector_zero (temp_bitmap, n_basic_blocks);
6038 /* The optimistic setting of dominators requires us to put every
6039 block on the work list initially. */
6040 qin = qout = worklist;
6041 for (bb = 0; bb < n_basic_blocks; bb++)
6043 *qin++ = BASIC_BLOCK (bb);
6044 BASIC_BLOCK (bb)->aux = BASIC_BLOCK (bb);
6046 qlen = n_basic_blocks;
6049 /* We want a maximal solution, so initially assume everything dominates
6051 sbitmap_vector_ones (dominators, n_basic_blocks);
6053 /* Mark successors of the entry block so we can identify them below. */
6054 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
6055 e->dest->aux = ENTRY_BLOCK_PTR;
6057 /* Iterate until the worklist is empty. */
6060 /* Take the first entry off the worklist. */
6061 basic_block b = *qout++;
6062 if (qout >= workend)
6068 /* Compute the intersection of the dominators of all the
6071 If one of the predecessor blocks is the ENTRY block, then the
6072 intersection of the dominators of the predecessor blocks is
6073 defined as the null set. We can identify such blocks by the
6074 special value in the AUX field in the block structure. */
6075 if (b->aux == ENTRY_BLOCK_PTR)
6077 /* Do not clear the aux field for blocks which are
6078 successors of the ENTRY block. That way we we never
6079 add them to the worklist again.
6081 The intersect of dominators of the preds of this block is
6082 defined as the null set. */
6083 sbitmap_zero (temp_bitmap[bb]);
6087 /* Clear the aux field of this block so it can be added to
6088 the worklist again if necessary. */
6090 sbitmap_intersection_of_preds (temp_bitmap[bb], dominators, bb);
6093 /* Make sure each block always dominates itself. */
6094 SET_BIT (temp_bitmap[bb], bb);
6096 /* If the out state of this block changed, then we need to
6097 add the successors of this block to the worklist if they
6098 are not already on the worklist. */
6099 if (sbitmap_a_and_b (dominators[bb], dominators[bb], temp_bitmap[bb]))
6101 for (e = b->succ; e; e = e->succ_next)
6103 if (!e->dest->aux && e->dest != EXIT_BLOCK_PTR)
6117 if (post_dominators)
6119 /* The optimistic setting of dominators requires us to put every
6120 block on the work list initially. */
6121 qin = qout = worklist;
6122 for (bb = 0; bb < n_basic_blocks; bb++)
6124 *qin++ = BASIC_BLOCK (bb);
6125 BASIC_BLOCK (bb)->aux = BASIC_BLOCK (bb);
6127 qlen = n_basic_blocks;
6130 /* We want a maximal solution, so initially assume everything post
6131 dominates everything else. */
6132 sbitmap_vector_ones (post_dominators, n_basic_blocks);
6134 /* Mark predecessors of the exit block so we can identify them below. */
6135 for (e = EXIT_BLOCK_PTR->pred; e; e = e->pred_next)
6136 e->src->aux = EXIT_BLOCK_PTR;
6138 /* Iterate until the worklist is empty. */
6141 /* Take the first entry off the worklist. */
6142 basic_block b = *qout++;
6143 if (qout >= workend)
6149 /* Compute the intersection of the post dominators of all the
6152 If one of the successor blocks is the EXIT block, then the
6153 intersection of the dominators of the successor blocks is
6154 defined as the null set. We can identify such blocks by the
6155 special value in the AUX field in the block structure. */
6156 if (b->aux == EXIT_BLOCK_PTR)
6158 /* Do not clear the aux field for blocks which are
6159 predecessors of the EXIT block. That way we we never
6160 add them to the worklist again.
6162 The intersect of dominators of the succs of this block is
6163 defined as the null set. */
6164 sbitmap_zero (temp_bitmap[bb]);
6168 /* Clear the aux field of this block so it can be added to
6169 the worklist again if necessary. */
6171 sbitmap_intersection_of_succs (temp_bitmap[bb],
6172 post_dominators, bb);
6175 /* Make sure each block always post dominates itself. */
6176 SET_BIT (temp_bitmap[bb], bb);
6178 /* If the out state of this block changed, then we need to
6179 add the successors of this block to the worklist if they
6180 are not already on the worklist. */
6181 if (sbitmap_a_and_b (post_dominators[bb],
6182 post_dominators[bb],
6185 for (e = b->pred; e; e = e->pred_next)
6187 if (!e->src->aux && e->src != ENTRY_BLOCK_PTR)
6205 /* Given DOMINATORS, compute the immediate dominators into IDOM. If a
6206 block dominates only itself, its entry remains as INVALID_BLOCK. */
6209 compute_immediate_dominators (idom, dominators)
6211 sbitmap *dominators;
6216 tmp = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
6218 /* Begin with tmp(n) = dom(n) - { n }. */
6219 for (b = n_basic_blocks; --b >= 0; )
6221 sbitmap_copy (tmp[b], dominators[b]);
6222 RESET_BIT (tmp[b], b);
6225 /* Subtract out all of our dominator's dominators. */
6226 for (b = n_basic_blocks; --b >= 0; )
6228 sbitmap tmp_b = tmp[b];
6231 for (s = n_basic_blocks; --s >= 0; )
6232 if (TEST_BIT (tmp_b, s))
6233 sbitmap_difference (tmp_b, tmp_b, tmp[s]);
6236 /* Find the one bit set in the bitmap and put it in the output array. */
6237 for (b = n_basic_blocks; --b >= 0; )
6240 EXECUTE_IF_SET_IN_SBITMAP (tmp[b], 0, t, { idom[b] = t; });
6243 sbitmap_vector_free (tmp);
6246 /* Given POSTDOMINATORS, compute the immediate postdominators into
6247 IDOM. If a block is only dominated by itself, its entry remains as
6251 compute_immediate_postdominators (idom, postdominators)
6253 sbitmap *postdominators;
6255 compute_immediate_dominators (idom, postdominators);
6259 /* Recompute register set/reference counts immediately prior to register
6262 This avoids problems with set/reference counts changing to/from values
6263 which have special meanings to the register allocators.
6265 Additionally, the reference counts are the primary component used by the
6266 register allocators to prioritize pseudos for allocation to hard regs.
6267 More accurate reference counts generally lead to better register allocation.
6269 F is the first insn to be scanned.
6271 LOOP_STEP denotes how much loop_depth should be incremented per
6272 loop nesting level in order to increase the ref count more for
6273 references in a loop.
6275 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
6276 possibly other information which is used by the register allocators. */
6279 recompute_reg_usage (f, loop_step)
6280 rtx f ATTRIBUTE_UNUSED;
6281 int loop_step ATTRIBUTE_UNUSED;
6283 allocate_reg_life_data ();
6284 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
6287 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
6288 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
6289 of the number of registers that died. */
6292 count_or_remove_death_notes (blocks, kill)
6298 for (i = n_basic_blocks - 1; i >= 0; --i)
6303 if (blocks && ! TEST_BIT (blocks, i))
6306 bb = BASIC_BLOCK (i);
6308 for (insn = bb->head; ; insn = NEXT_INSN (insn))
6310 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
6312 rtx *pprev = ®_NOTES (insn);
6317 switch (REG_NOTE_KIND (link))
6320 if (GET_CODE (XEXP (link, 0)) == REG)
6322 rtx reg = XEXP (link, 0);
6325 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
6328 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
6336 rtx next = XEXP (link, 1);
6337 free_EXPR_LIST_node (link);
6338 *pprev = link = next;
6344 pprev = &XEXP (link, 1);
6351 if (insn == bb->end)
6359 /* Record INSN's block as BB. */
6362 set_block_for_insn (insn, bb)
6366 size_t uid = INSN_UID (insn);
6367 if (uid >= basic_block_for_insn->num_elements)
6371 /* Add one-eighth the size so we don't keep calling xrealloc. */
6372 new_size = uid + (uid + 7) / 8;
6374 VARRAY_GROW (basic_block_for_insn, new_size);
6376 VARRAY_BB (basic_block_for_insn, uid) = bb;
6379 /* Record INSN's block number as BB. */
6380 /* ??? This has got to go. */
6383 set_block_num (insn, bb)
6387 set_block_for_insn (insn, BASIC_BLOCK (bb));
6390 /* Verify the CFG consistency. This function check some CFG invariants and
6391 aborts when something is wrong. Hope that this function will help to
6392 convert many optimization passes to preserve CFG consistent.
6394 Currently it does following checks:
6396 - test head/end pointers
6397 - overlapping of basic blocks
6398 - edge list corectness
6399 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
6400 - tails of basic blocks (ensure that boundary is necesary)
6401 - scans body of the basic block for JUMP_INSN, CODE_LABEL
6402 and NOTE_INSN_BASIC_BLOCK
6403 - check that all insns are in the basic blocks
6404 (except the switch handling code, barriers and notes)
6405 - check that all returns are followed by barriers
6407 In future it can be extended check a lot of other stuff as well
6408 (reachability of basic blocks, life information, etc. etc.). */
6413 const int max_uid = get_max_uid ();
6414 const rtx rtx_first = get_insns ();
6415 rtx last_head = get_last_insn ();
6416 basic_block *bb_info;
6418 int i, last_bb_num_seen, num_bb_notes, err = 0;
6420 bb_info = (basic_block *) xcalloc (max_uid, sizeof (basic_block));
6422 for (i = n_basic_blocks - 1; i >= 0; i--)
6424 basic_block bb = BASIC_BLOCK (i);
6425 rtx head = bb->head;
6428 /* Verify the end of the basic block is in the INSN chain. */
6429 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
6434 error ("End insn %d for block %d not found in the insn stream.",
6435 INSN_UID (end), bb->index);
6439 /* Work backwards from the end to the head of the basic block
6440 to verify the head is in the RTL chain. */
6441 for ( ; x != NULL_RTX; x = PREV_INSN (x))
6443 /* While walking over the insn chain, verify insns appear
6444 in only one basic block and initialize the BB_INFO array
6445 used by other passes. */
6446 if (bb_info[INSN_UID (x)] != NULL)
6448 error ("Insn %d is in multiple basic blocks (%d and %d)",
6449 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
6452 bb_info[INSN_UID (x)] = bb;
6459 error ("Head insn %d for block %d not found in the insn stream.",
6460 INSN_UID (head), bb->index);
6467 /* Now check the basic blocks (boundaries etc.) */
6468 for (i = n_basic_blocks - 1; i >= 0; i--)
6470 basic_block bb = BASIC_BLOCK (i);
6471 /* Check corectness of edge lists */
6479 fprintf (stderr, "verify_flow_info: Basic block %d succ edge is corrupted\n",
6481 fprintf (stderr, "Predecessor: ");
6482 dump_edge_info (stderr, e, 0);
6483 fprintf (stderr, "\nSuccessor: ");
6484 dump_edge_info (stderr, e, 1);
6488 if (e->dest != EXIT_BLOCK_PTR)
6490 edge e2 = e->dest->pred;
6491 while (e2 && e2 != e)
6495 error ("Basic block %i edge lists are corrupted", bb->index);
6507 error ("Basic block %d pred edge is corrupted", bb->index);
6508 fputs ("Predecessor: ", stderr);
6509 dump_edge_info (stderr, e, 0);
6510 fputs ("\nSuccessor: ", stderr);
6511 dump_edge_info (stderr, e, 1);
6512 fputc ('\n', stderr);
6515 if (e->src != ENTRY_BLOCK_PTR)
6517 edge e2 = e->src->succ;
6518 while (e2 && e2 != e)
6522 error ("Basic block %i edge lists are corrupted", bb->index);
6529 /* OK pointers are correct. Now check the header of basic
6530 block. It ought to contain optional CODE_LABEL followed
6531 by NOTE_BASIC_BLOCK. */
6533 if (GET_CODE (x) == CODE_LABEL)
6537 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
6543 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
6545 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d\n",
6552 /* Do checks for empty blocks here */
6559 if (NOTE_INSN_BASIC_BLOCK_P (x))
6561 error ("NOTE_INSN_BASIC_BLOCK %d in the middle of basic block %d",
6562 INSN_UID (x), bb->index);
6569 if (GET_CODE (x) == JUMP_INSN
6570 || GET_CODE (x) == CODE_LABEL
6571 || GET_CODE (x) == BARRIER)
6573 error ("In basic block %d:", bb->index);
6574 fatal_insn ("Flow control insn inside a basic block", x);
6582 last_bb_num_seen = -1;
6587 if (NOTE_INSN_BASIC_BLOCK_P (x))
6589 basic_block bb = NOTE_BASIC_BLOCK (x);
6591 if (bb->index != last_bb_num_seen + 1)
6592 fatal ("Basic blocks not numbered consecutively");
6593 last_bb_num_seen = bb->index;
6596 if (!bb_info[INSN_UID (x)])
6598 switch (GET_CODE (x))
6605 /* An addr_vec is placed outside any block block. */
6607 && GET_CODE (NEXT_INSN (x)) == JUMP_INSN
6608 && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
6609 || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
6614 /* But in any case, non-deletable labels can appear anywhere. */
6618 fatal_insn ("Insn outside basic block", x);
6622 if (GET_RTX_CLASS (GET_CODE (x)) == 'i'
6623 && GET_CODE (x) == JUMP_INSN
6624 && returnjump_p (x) && ! condjump_p (x)
6625 && ! (NEXT_INSN (x) && GET_CODE (NEXT_INSN (x)) == BARRIER))
6626 fatal_insn ("Return not followed by barrier", x);
6631 if (num_bb_notes != n_basic_blocks)
6632 fatal ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
6633 num_bb_notes, n_basic_blocks);
6642 /* Functions to access an edge list with a vector representation.
6643 Enough data is kept such that given an index number, the
6644 pred and succ that edge represents can be determined, or
6645 given a pred and a succ, its index number can be returned.
6646 This allows algorithms which consume a lot of memory to
6647 represent the normally full matrix of edge (pred,succ) with a
6648 single indexed vector, edge (EDGE_INDEX (pred, succ)), with no
6649 wasted space in the client code due to sparse flow graphs. */
6651 /* This functions initializes the edge list. Basically the entire
6652 flowgraph is processed, and all edges are assigned a number,
6653 and the data structure is filled in. */
6657 struct edge_list *elist;
6663 block_count = n_basic_blocks + 2; /* Include the entry and exit blocks. */
6667 /* Determine the number of edges in the flow graph by counting successor
6668 edges on each basic block. */
6669 for (x = 0; x < n_basic_blocks; x++)
6671 basic_block bb = BASIC_BLOCK (x);
6673 for (e = bb->succ; e; e = e->succ_next)
6676 /* Don't forget successors of the entry block. */
6677 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
6680 elist = (struct edge_list *) xmalloc (sizeof (struct edge_list));
6681 elist->num_blocks = block_count;
6682 elist->num_edges = num_edges;
6683 elist->index_to_edge = (edge *) xmalloc (sizeof (edge) * num_edges);
6687 /* Follow successors of the entry block, and register these edges. */
6688 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
6690 elist->index_to_edge[num_edges] = e;
6694 for (x = 0; x < n_basic_blocks; x++)
6696 basic_block bb = BASIC_BLOCK (x);
6698 /* Follow all successors of blocks, and register these edges. */
6699 for (e = bb->succ; e; e = e->succ_next)
6701 elist->index_to_edge[num_edges] = e;
6708 /* This function free's memory associated with an edge list. */
6710 free_edge_list (elist)
6711 struct edge_list *elist;
6715 free (elist->index_to_edge);
6720 /* This function provides debug output showing an edge list. */
6722 print_edge_list (f, elist)
6724 struct edge_list *elist;
6727 fprintf(f, "Compressed edge list, %d BBs + entry & exit, and %d edges\n",
6728 elist->num_blocks - 2, elist->num_edges);
6730 for (x = 0; x < elist->num_edges; x++)
6732 fprintf (f, " %-4d - edge(", x);
6733 if (INDEX_EDGE_PRED_BB (elist, x) == ENTRY_BLOCK_PTR)
6734 fprintf (f,"entry,");
6736 fprintf (f,"%d,", INDEX_EDGE_PRED_BB (elist, x)->index);
6738 if (INDEX_EDGE_SUCC_BB (elist, x) == EXIT_BLOCK_PTR)
6739 fprintf (f,"exit)\n");
6741 fprintf (f,"%d)\n", INDEX_EDGE_SUCC_BB (elist, x)->index);
6745 /* This function provides an internal consistency check of an edge list,
6746 verifying that all edges are present, and that there are no
6749 verify_edge_list (f, elist)
6751 struct edge_list *elist;
6753 int x, pred, succ, index;
6756 for (x = 0; x < n_basic_blocks; x++)
6758 basic_block bb = BASIC_BLOCK (x);
6760 for (e = bb->succ; e; e = e->succ_next)
6762 pred = e->src->index;
6763 succ = e->dest->index;
6764 index = EDGE_INDEX (elist, e->src, e->dest);
6765 if (index == EDGE_INDEX_NO_EDGE)
6767 fprintf (f, "*p* No index for edge from %d to %d\n",pred, succ);
6770 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
6771 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
6772 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
6773 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
6774 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
6775 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
6778 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
6780 pred = e->src->index;
6781 succ = e->dest->index;
6782 index = EDGE_INDEX (elist, e->src, e->dest);
6783 if (index == EDGE_INDEX_NO_EDGE)
6785 fprintf (f, "*p* No index for edge from %d to %d\n",pred, succ);
6788 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
6789 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
6790 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
6791 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
6792 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
6793 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
6795 /* We've verified that all the edges are in the list, no lets make sure
6796 there are no spurious edges in the list. */
6798 for (pred = 0 ; pred < n_basic_blocks; pred++)
6799 for (succ = 0 ; succ < n_basic_blocks; succ++)
6801 basic_block p = BASIC_BLOCK (pred);
6802 basic_block s = BASIC_BLOCK (succ);
6806 for (e = p->succ; e; e = e->succ_next)
6812 for (e = s->pred; e; e = e->pred_next)
6818 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
6819 == EDGE_INDEX_NO_EDGE && found_edge != 0)
6820 fprintf (f, "*** Edge (%d, %d) appears to not have an index\n",
6822 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
6823 != EDGE_INDEX_NO_EDGE && found_edge == 0)
6824 fprintf (f, "*** Edge (%d, %d) has index %d, but there is no edge\n",
6825 pred, succ, EDGE_INDEX (elist, BASIC_BLOCK (pred),
6826 BASIC_BLOCK (succ)));
6828 for (succ = 0 ; succ < n_basic_blocks; succ++)
6830 basic_block p = ENTRY_BLOCK_PTR;
6831 basic_block s = BASIC_BLOCK (succ);
6835 for (e = p->succ; e; e = e->succ_next)
6841 for (e = s->pred; e; e = e->pred_next)
6847 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
6848 == EDGE_INDEX_NO_EDGE && found_edge != 0)
6849 fprintf (f, "*** Edge (entry, %d) appears to not have an index\n",
6851 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
6852 != EDGE_INDEX_NO_EDGE && found_edge == 0)
6853 fprintf (f, "*** Edge (entry, %d) has index %d, but no edge exists\n",
6854 succ, EDGE_INDEX (elist, ENTRY_BLOCK_PTR,
6855 BASIC_BLOCK (succ)));
6857 for (pred = 0 ; pred < n_basic_blocks; pred++)
6859 basic_block p = BASIC_BLOCK (pred);
6860 basic_block s = EXIT_BLOCK_PTR;
6864 for (e = p->succ; e; e = e->succ_next)
6870 for (e = s->pred; e; e = e->pred_next)
6876 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
6877 == EDGE_INDEX_NO_EDGE && found_edge != 0)
6878 fprintf (f, "*** Edge (%d, exit) appears to not have an index\n",
6880 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
6881 != EDGE_INDEX_NO_EDGE && found_edge == 0)
6882 fprintf (f, "*** Edge (%d, exit) has index %d, but no edge exists\n",
6883 pred, EDGE_INDEX (elist, BASIC_BLOCK (pred),
6888 /* This routine will determine what, if any, edge there is between
6889 a specified predecessor and successor. */
6892 find_edge_index (edge_list, pred, succ)
6893 struct edge_list *edge_list;
6894 basic_block pred, succ;
6897 for (x = 0; x < NUM_EDGES (edge_list); x++)
6899 if (INDEX_EDGE_PRED_BB (edge_list, x) == pred
6900 && INDEX_EDGE_SUCC_BB (edge_list, x) == succ)
6903 return (EDGE_INDEX_NO_EDGE);
6906 /* This function will remove an edge from the flow graph. */
6911 edge last_pred = NULL;
6912 edge last_succ = NULL;
6914 basic_block src, dest;
6917 for (tmp = src->succ; tmp && tmp != e; tmp = tmp->succ_next)
6923 last_succ->succ_next = e->succ_next;
6925 src->succ = e->succ_next;
6927 for (tmp = dest->pred; tmp && tmp != e; tmp = tmp->pred_next)
6933 last_pred->pred_next = e->pred_next;
6935 dest->pred = e->pred_next;
6941 /* This routine will remove any fake successor edges for a basic block.
6942 When the edge is removed, it is also removed from whatever predecessor
6945 remove_fake_successors (bb)
6949 for (e = bb->succ; e ; )
6953 if ((tmp->flags & EDGE_FAKE) == EDGE_FAKE)
6958 /* This routine will remove all fake edges from the flow graph. If
6959 we remove all fake successors, it will automatically remove all
6960 fake predecessors. */
6962 remove_fake_edges ()
6966 for (x = 0; x < n_basic_blocks; x++)
6967 remove_fake_successors (BASIC_BLOCK (x));
6969 /* We've handled all successors except the entry block's. */
6970 remove_fake_successors (ENTRY_BLOCK_PTR);
6973 /* This function will add a fake edge between any block which has no
6974 successors, and the exit block. Some data flow equations require these
6977 add_noreturn_fake_exit_edges ()
6981 for (x = 0; x < n_basic_blocks; x++)
6982 if (BASIC_BLOCK (x)->succ == NULL)
6983 make_edge (NULL, BASIC_BLOCK (x), EXIT_BLOCK_PTR, EDGE_FAKE);
6986 /* Redirect an edge's successor from one block to another. */
6989 redirect_edge_succ (e, new_succ)
6991 basic_block new_succ;
6995 /* Disconnect the edge from the old successor block. */
6996 for (pe = &e->dest->pred; *pe != e ; pe = &(*pe)->pred_next)
6998 *pe = (*pe)->pred_next;
7000 /* Reconnect the edge to the new successor block. */
7001 e->pred_next = new_succ->pred;
7006 /* Redirect an edge's predecessor from one block to another. */
7009 redirect_edge_pred (e, new_pred)
7011 basic_block new_pred;
7015 /* Disconnect the edge from the old predecessor block. */
7016 for (pe = &e->src->succ; *pe != e ; pe = &(*pe)->succ_next)
7018 *pe = (*pe)->succ_next;
7020 /* Reconnect the edge to the new predecessor block. */
7021 e->succ_next = new_pred->succ;
7026 /* Dump the list of basic blocks in the bitmap NODES. */
7028 flow_nodes_print (str, nodes, file)
7030 const sbitmap nodes;
7035 fprintf (file, "%s { ", str);
7036 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {fprintf (file, "%d ", node);});
7037 fputs ("}\n", file);
7041 /* Dump the list of exiting edges in the array EDGES. */
7043 flow_exits_print (str, edges, num_edges, file)
7051 fprintf (file, "%s { ", str);
7052 for (i = 0; i < num_edges; i++)
7053 fprintf (file, "%d->%d ", edges[i]->src->index, edges[i]->dest->index);
7054 fputs ("}\n", file);
7058 /* Dump loop related CFG information. */
7060 flow_loops_cfg_dump (loops, file)
7061 const struct loops *loops;
7066 if (! loops->num || ! file || ! loops->cfg.dom)
7069 for (i = 0; i < n_basic_blocks; i++)
7073 fprintf (file, ";; %d succs { ", i);
7074 for (succ = BASIC_BLOCK (i)->succ; succ; succ = succ->succ_next)
7075 fprintf (file, "%d ", succ->dest->index);
7076 flow_nodes_print ("} dom", loops->cfg.dom[i], file);
7080 /* Dump the DFS node order. */
7081 if (loops->cfg.dfs_order)
7083 fputs (";; DFS order: ", file);
7084 for (i = 0; i < n_basic_blocks; i++)
7085 fprintf (file, "%d ", loops->cfg.dfs_order[i]);
7088 /* Dump the reverse completion node order. */
7089 if (loops->cfg.rc_order)
7091 fputs (";; RC order: ", file);
7092 for (i = 0; i < n_basic_blocks; i++)
7093 fprintf (file, "%d ", loops->cfg.rc_order[i]);
7099 /* Return non-zero if the nodes of LOOP are a subset of OUTER. */
7101 flow_loop_nested_p (outer, loop)
7105 return sbitmap_a_subset_b_p (loop->nodes, outer->nodes);
7109 /* Dump the loop information specified by LOOPS to the stream FILE. */
7111 flow_loops_dump (loops, file, verbose)
7112 const struct loops *loops;
7119 num_loops = loops->num;
7120 if (! num_loops || ! file)
7123 fprintf (file, ";; %d loops found, %d levels\n",
7124 num_loops, loops->levels);
7126 for (i = 0; i < num_loops; i++)
7128 struct loop *loop = &loops->array[i];
7130 fprintf (file, ";; loop %d (%d to %d):\n;; header %d, latch %d, pre-header %d, depth %d, level %d, outer %ld\n",
7131 i, INSN_UID (loop->header->head), INSN_UID (loop->latch->end),
7132 loop->header->index, loop->latch->index,
7133 loop->pre_header ? loop->pre_header->index : -1,
7134 loop->depth, loop->level,
7135 (long) (loop->outer ? (loop->outer - loops->array) : -1));
7136 fprintf (file, ";; %d", loop->num_nodes);
7137 flow_nodes_print (" nodes", loop->nodes, file);
7138 fprintf (file, ";; %d", loop->num_exits);
7139 flow_exits_print (" exits", loop->exits, loop->num_exits, file);
7145 for (j = 0; j < i; j++)
7147 struct loop *oloop = &loops->array[j];
7149 if (loop->header == oloop->header)
7154 smaller = loop->num_nodes < oloop->num_nodes;
7156 /* If the union of LOOP and OLOOP is different than
7157 the larger of LOOP and OLOOP then LOOP and OLOOP
7158 must be disjoint. */
7159 disjoint = ! flow_loop_nested_p (smaller ? loop : oloop,
7160 smaller ? oloop : loop);
7162 ";; loop header %d shared by loops %d, %d %s\n",
7163 loop->header->index, i, j,
7164 disjoint ? "disjoint" : "nested");
7171 /* Print diagnostics to compare our concept of a loop with
7172 what the loop notes say. */
7173 if (GET_CODE (PREV_INSN (loop->first->head)) != NOTE
7174 || NOTE_LINE_NUMBER (PREV_INSN (loop->first->head))
7175 != NOTE_INSN_LOOP_BEG)
7176 fprintf (file, ";; No NOTE_INSN_LOOP_BEG at %d\n",
7177 INSN_UID (PREV_INSN (loop->first->head)));
7178 if (GET_CODE (NEXT_INSN (loop->last->end)) != NOTE
7179 || NOTE_LINE_NUMBER (NEXT_INSN (loop->last->end))
7180 != NOTE_INSN_LOOP_END)
7181 fprintf (file, ";; No NOTE_INSN_LOOP_END at %d\n",
7182 INSN_UID (NEXT_INSN (loop->last->end)));
7187 flow_loops_cfg_dump (loops, file);
7191 /* Free all the memory allocated for LOOPS. */
7193 flow_loops_free (loops)
7194 struct loops *loops;
7203 /* Free the loop descriptors. */
7204 for (i = 0; i < loops->num; i++)
7206 struct loop *loop = &loops->array[i];
7209 sbitmap_free (loop->nodes);
7213 free (loops->array);
7214 loops->array = NULL;
7217 sbitmap_vector_free (loops->cfg.dom);
7218 if (loops->cfg.dfs_order)
7219 free (loops->cfg.dfs_order);
7221 sbitmap_free (loops->shared_headers);
7226 /* Find the exits from the loop using the bitmap of loop nodes NODES
7227 and store in EXITS array. Return the number of exits from the
7230 flow_loop_exits_find (nodes, exits)
7231 const sbitmap nodes;
7240 /* Check all nodes within the loop to see if there are any
7241 successors not in the loop. Note that a node may have multiple
7244 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
7245 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
7247 basic_block dest = e->dest;
7249 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
7257 *exits = (edge *) xmalloc (num_exits * sizeof (edge *));
7259 /* Store all exiting edges into an array. */
7261 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
7262 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
7264 basic_block dest = e->dest;
7266 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
7267 (*exits)[num_exits++] = e;
7275 /* Find the nodes contained within the loop with header HEADER and
7276 latch LATCH and store in NODES. Return the number of nodes within
7279 flow_loop_nodes_find (header, latch, nodes)
7288 stack = (basic_block *) xmalloc (n_basic_blocks * sizeof (basic_block));
7291 /* Start with only the loop header in the set of loop nodes. */
7292 sbitmap_zero (nodes);
7293 SET_BIT (nodes, header->index);
7295 header->loop_depth++;
7297 /* Push the loop latch on to the stack. */
7298 if (! TEST_BIT (nodes, latch->index))
7300 SET_BIT (nodes, latch->index);
7301 latch->loop_depth++;
7303 stack[sp++] = latch;
7312 for (e = node->pred; e; e = e->pred_next)
7314 basic_block ancestor = e->src;
7316 /* If each ancestor not marked as part of loop, add to set of
7317 loop nodes and push on to stack. */
7318 if (ancestor != ENTRY_BLOCK_PTR
7319 && ! TEST_BIT (nodes, ancestor->index))
7321 SET_BIT (nodes, ancestor->index);
7322 ancestor->loop_depth++;
7324 stack[sp++] = ancestor;
7333 /* Compute the depth first search order and store in the array
7334 DFS_ORDER if non-zero, marking the nodes visited in VISITED. If
7335 RC_ORDER is non-zero, return the reverse completion number for each
7336 node. Returns the number of nodes visited. A depth first search
7337 tries to get as far away from the starting point as quickly as
7340 flow_depth_first_order_compute (dfs_order, rc_order)
7347 int rcnum = n_basic_blocks - 1;
7350 /* Allocate stack for back-tracking up CFG. */
7351 stack = (edge *) xmalloc ((n_basic_blocks + 1) * sizeof (edge));
7354 /* Allocate bitmap to track nodes that have been visited. */
7355 visited = sbitmap_alloc (n_basic_blocks);
7357 /* None of the nodes in the CFG have been visited yet. */
7358 sbitmap_zero (visited);
7360 /* Push the first edge on to the stack. */
7361 stack[sp++] = ENTRY_BLOCK_PTR->succ;
7369 /* Look at the edge on the top of the stack. */
7374 /* Check if the edge destination has been visited yet. */
7375 if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index))
7377 /* Mark that we have visited the destination. */
7378 SET_BIT (visited, dest->index);
7381 dfs_order[dfsnum++] = dest->index;
7385 /* Since the DEST node has been visited for the first
7386 time, check its successors. */
7387 stack[sp++] = dest->succ;
7391 /* There are no successors for the DEST node so assign
7392 its reverse completion number. */
7394 rc_order[rcnum--] = dest->index;
7399 if (! e->succ_next && src != ENTRY_BLOCK_PTR)
7401 /* There are no more successors for the SRC node
7402 so assign its reverse completion number. */
7404 rc_order[rcnum--] = src->index;
7408 stack[sp - 1] = e->succ_next;
7415 sbitmap_free (visited);
7417 /* The number of nodes visited should not be greater than
7419 if (dfsnum > n_basic_blocks)
7422 /* There are some nodes left in the CFG that are unreachable. */
7423 if (dfsnum < n_basic_blocks)
7429 /* Return the block for the pre-header of the loop with header
7430 HEADER where DOM specifies the dominator information. Return NULL if
7431 there is no pre-header. */
7433 flow_loop_pre_header_find (header, dom)
7437 basic_block pre_header;
7440 /* If block p is a predecessor of the header and is the only block
7441 that the header does not dominate, then it is the pre-header. */
7443 for (e = header->pred; e; e = e->pred_next)
7445 basic_block node = e->src;
7447 if (node != ENTRY_BLOCK_PTR
7448 && ! TEST_BIT (dom[node->index], header->index))
7450 if (pre_header == NULL)
7454 /* There are multiple edges into the header from outside
7455 the loop so there is no pre-header block. */
7465 /* Add LOOP to the loop hierarchy tree where PREVLOOP was the loop
7466 previously added. The insertion algorithm assumes that the loops
7467 are added in the order found by a depth first search of the CFG. */
7469 flow_loop_tree_node_add (prevloop, loop)
7470 struct loop *prevloop;
7474 if (flow_loop_nested_p (prevloop, loop))
7476 prevloop->inner = loop;
7477 loop->outer = prevloop;
7481 while (prevloop->outer)
7483 if (flow_loop_nested_p (prevloop->outer, loop))
7485 prevloop->next = loop;
7486 loop->outer = prevloop->outer;
7489 prevloop = prevloop->outer;
7492 prevloop->next = loop;
7497 /* Build the loop hierarchy tree for LOOPS. */
7499 flow_loops_tree_build (loops)
7500 struct loops *loops;
7505 num_loops = loops->num;
7509 /* Root the loop hierarchy tree with the first loop found.
7510 Since we used a depth first search this should be the
7512 loops->tree = &loops->array[0];
7513 loops->tree->outer = loops->tree->inner = loops->tree->next = NULL;
7515 /* Add the remaining loops to the tree. */
7516 for (i = 1; i < num_loops; i++)
7517 flow_loop_tree_node_add (&loops->array[i - 1], &loops->array[i]);
7521 /* Helper function to compute loop nesting depth and enclosed loop level
7522 for the natural loop specified by LOOP at the loop depth DEPTH.
7523 Returns the loop level. */
7525 flow_loop_level_compute (loop, depth)
7535 /* Traverse loop tree assigning depth and computing level as the
7536 maximum level of all the inner loops of this loop. The loop
7537 level is equivalent to the height of the loop in the loop tree
7538 and corresponds to the number of enclosed loop levels (including
7540 for (inner = loop->inner; inner; inner = inner->next)
7544 ilevel = flow_loop_level_compute (inner, depth + 1) + 1;
7549 loop->level = level;
7550 loop->depth = depth;
7555 /* Compute the loop nesting depth and enclosed loop level for the loop
7556 hierarchy tree specfied by LOOPS. Return the maximum enclosed loop
7560 flow_loops_level_compute (loops)
7561 struct loops *loops;
7567 /* Traverse all the outer level loops. */
7568 for (loop = loops->tree; loop; loop = loop->next)
7570 level = flow_loop_level_compute (loop, 1);
7578 /* Find all the natural loops in the function and save in LOOPS structure
7579 and recalculate loop_depth information in basic block structures.
7580 Return the number of natural loops found. */
7583 flow_loops_find (loops)
7584 struct loops *loops;
7596 loops->array = NULL;
7601 /* Taking care of this degenerate case makes the rest of
7602 this code simpler. */
7603 if (n_basic_blocks == 0)
7606 /* Compute the dominators. */
7607 dom = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
7608 compute_flow_dominators (dom, NULL);
7610 /* Count the number of loop edges (back edges). This should be the
7611 same as the number of natural loops. Also clear the loop_depth
7612 and as we work from inner->outer in a loop nest we call
7613 find_loop_nodes_find which will increment loop_depth for nodes
7614 within the current loop, which happens to enclose inner loops. */
7617 for (b = 0; b < n_basic_blocks; b++)
7619 BASIC_BLOCK (b)->loop_depth = 0;
7620 for (e = BASIC_BLOCK (b)->pred; e; e = e->pred_next)
7622 basic_block latch = e->src;
7624 /* Look for back edges where a predecessor is dominated
7625 by this block. A natural loop has a single entry
7626 node (header) that dominates all the nodes in the
7627 loop. It also has single back edge to the header
7628 from a latch node. Note that multiple natural loops
7629 may share the same header. */
7630 if (latch != ENTRY_BLOCK_PTR && TEST_BIT (dom[latch->index], b))
7637 /* Compute depth first search order of the CFG so that outer
7638 natural loops will be found before inner natural loops. */
7639 dfs_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
7640 rc_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
7641 flow_depth_first_order_compute (dfs_order, rc_order);
7643 /* Allocate loop structures. */
7645 = (struct loop *) xcalloc (num_loops, sizeof (struct loop));
7647 headers = sbitmap_alloc (n_basic_blocks);
7648 sbitmap_zero (headers);
7650 loops->shared_headers = sbitmap_alloc (n_basic_blocks);
7651 sbitmap_zero (loops->shared_headers);
7653 /* Find and record information about all the natural loops
7656 for (b = 0; b < n_basic_blocks; b++)
7660 /* Search the nodes of the CFG in DFS order that we can find
7661 outer loops first. */
7662 header = BASIC_BLOCK (rc_order[b]);
7664 /* Look for all the possible latch blocks for this header. */
7665 for (e = header->pred; e; e = e->pred_next)
7667 basic_block latch = e->src;
7669 /* Look for back edges where a predecessor is dominated
7670 by this block. A natural loop has a single entry
7671 node (header) that dominates all the nodes in the
7672 loop. It also has single back edge to the header
7673 from a latch node. Note that multiple natural loops
7674 may share the same header. */
7675 if (latch != ENTRY_BLOCK_PTR
7676 && TEST_BIT (dom[latch->index], header->index))
7680 loop = loops->array + num_loops;
7682 loop->header = header;
7683 loop->latch = latch;
7684 loop->num = num_loops;
7686 /* Keep track of blocks that are loop headers so
7687 that we can tell which loops should be merged. */
7688 if (TEST_BIT (headers, header->index))
7689 SET_BIT (loops->shared_headers, header->index);
7690 SET_BIT (headers, header->index);
7692 /* Find nodes contained within the loop. */
7693 loop->nodes = sbitmap_alloc (n_basic_blocks);
7695 = flow_loop_nodes_find (header, latch, loop->nodes);
7697 /* Compute first and last blocks within the loop.
7698 These are often the same as the loop header and
7699 loop latch respectively, but this is not always
7702 = BASIC_BLOCK (sbitmap_first_set_bit (loop->nodes));
7704 = BASIC_BLOCK (sbitmap_last_set_bit (loop->nodes));
7706 /* Find edges which exit the loop. Note that a node
7707 may have several exit edges. */
7709 = flow_loop_exits_find (loop->nodes, &loop->exits);
7711 /* Look to see if the loop has a pre-header node. */
7713 = flow_loop_pre_header_find (header, dom);
7720 /* Natural loops with shared headers may either be disjoint or
7721 nested. Disjoint loops with shared headers cannot be inner
7722 loops and should be merged. For now just mark loops that share
7724 for (i = 0; i < num_loops; i++)
7725 if (TEST_BIT (loops->shared_headers, loops->array[i].header->index))
7726 loops->array[i].shared = 1;
7728 sbitmap_free (headers);
7731 loops->num = num_loops;
7733 /* Save CFG derived information to avoid recomputing it. */
7734 loops->cfg.dom = dom;
7735 loops->cfg.dfs_order = dfs_order;
7736 loops->cfg.rc_order = rc_order;
7738 /* Build the loop hierarchy tree. */
7739 flow_loops_tree_build (loops);
7741 /* Assign the loop nesting depth and enclosed loop level for each
7743 loops->levels = flow_loops_level_compute (loops);
7749 /* Return non-zero if edge E enters header of LOOP from outside of LOOP. */
7752 flow_loop_outside_edge_p (loop, e)
7753 const struct loop *loop;
7756 if (e->dest != loop->header)
7758 return (e->src == ENTRY_BLOCK_PTR)
7759 || ! TEST_BIT (loop->nodes, e->src->index);
7763 /* Clear LOG_LINKS fields of insns in a chain.
7764 Also clear the global_live_at_{start,end} fields of the basic block
7768 clear_log_links (insns)
7774 for (i = insns; i; i = NEXT_INSN (i))
7775 if (GET_RTX_CLASS (GET_CODE (i)) == 'i')
7778 for (b = 0; b < n_basic_blocks; b++)
7780 basic_block bb = BASIC_BLOCK (i);
7782 bb->global_live_at_start = NULL;
7783 bb->global_live_at_end = NULL;
7786 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
7787 EXIT_BLOCK_PTR->global_live_at_start = NULL;
7790 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
7791 correspond to the hard registers, if any, set in that map. This
7792 could be done far more efficiently by having all sorts of special-cases
7793 with moving single words, but probably isn't worth the trouble. */
7796 reg_set_to_hard_reg_set (to, from)
7802 EXECUTE_IF_SET_IN_BITMAP
7805 if (i >= FIRST_PSEUDO_REGISTER)
7807 SET_HARD_REG_BIT (*to, i);