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. */
22 /* This file contains the data flow analysis pass of the compiler. It
23 computes data flow information which tells combine_instructions
24 which insns to consider combining and controls register allocation.
26 Additional data flow information that is too bulky to record is
27 generated during the analysis, and is used at that time to create
28 autoincrement and autodecrement addressing.
30 The first step is dividing the function into basic blocks.
31 find_basic_blocks does this. Then life_analysis determines
32 where each register is live and where it is dead.
34 ** find_basic_blocks **
36 find_basic_blocks divides the current function's rtl into basic
37 blocks and constructs the CFG. The blocks are recorded in the
38 basic_block_info array; the CFG exists in the edge structures
39 referenced by the blocks.
41 find_basic_blocks also finds any unreachable loops and deletes them.
45 life_analysis is called immediately after find_basic_blocks.
46 It uses the basic block information to determine where each
47 hard or pseudo register is live.
49 ** live-register info **
51 The information about where each register is live is in two parts:
52 the REG_NOTES of insns, and the vector basic_block->global_live_at_start.
54 basic_block->global_live_at_start has an element for each basic
55 block, and the element is a bit-vector with a bit for each hard or
56 pseudo register. The bit is 1 if the register is live at the
57 beginning of the basic block.
59 Two types of elements can be added to an insn's REG_NOTES.
60 A REG_DEAD note is added to an insn's REG_NOTES for any register
61 that meets both of two conditions: The value in the register is not
62 needed in subsequent insns and the insn does not replace the value in
63 the register (in the case of multi-word hard registers, the value in
64 each register must be replaced by the insn to avoid a REG_DEAD note).
66 In the vast majority of cases, an object in a REG_DEAD note will be
67 used somewhere in the insn. The (rare) exception to this is if an
68 insn uses a multi-word hard register and only some of the registers are
69 needed in subsequent insns. In that case, REG_DEAD notes will be
70 provided for those hard registers that are not subsequently needed.
71 Partial REG_DEAD notes of this type do not occur when an insn sets
72 only some of the hard registers used in such a multi-word operand;
73 omitting REG_DEAD notes for objects stored in an insn is optional and
74 the desire to do so does not justify the complexity of the partial
77 REG_UNUSED notes are added for each register that is set by the insn
78 but is unused subsequently (if every register set by the insn is unused
79 and the insn does not reference memory or have some other side-effect,
80 the insn is deleted instead). If only part of a multi-word hard
81 register is used in a subsequent insn, REG_UNUSED notes are made for
82 the parts that will not be used.
84 To determine which registers are live after any insn, one can
85 start from the beginning of the basic block and scan insns, noting
86 which registers are set by each insn and which die there.
88 ** Other actions of life_analysis **
90 life_analysis sets up the LOG_LINKS fields of insns because the
91 information needed to do so is readily available.
93 life_analysis deletes insns whose only effect is to store a value
96 life_analysis notices cases where a reference to a register as
97 a memory address can be combined with a preceding or following
98 incrementation or decrementation of the register. The separate
99 instruction to increment or decrement is deleted and the address
100 is changed to a POST_INC or similar rtx.
102 Each time an incrementing or decrementing address is created,
103 a REG_INC element is added to the insn's REG_NOTES list.
105 life_analysis fills in certain vectors containing information about
106 register usage: REG_N_REFS, REG_N_DEATHS, REG_N_SETS, REG_LIVE_LENGTH,
107 REG_N_CALLS_CROSSED and REG_BASIC_BLOCK.
109 life_analysis sets current_function_sp_is_unchanging if the function
110 doesn't modify the stack pointer. */
114 Split out from life_analysis:
115 - local property discovery (bb->local_live, bb->local_set)
116 - global property computation
118 - pre/post modify transformation
126 #include "hard-reg-set.h"
127 #include "basic-block.h"
128 #include "insn-config.h"
132 #include "function.h"
136 #include "insn-flags.h"
141 #include "splay-tree.h"
143 #define obstack_chunk_alloc xmalloc
144 #define obstack_chunk_free free
146 /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
147 the stack pointer does not matter. The value is tested only in
148 functions that have frame pointers.
149 No definition is equivalent to always zero. */
150 #ifndef EXIT_IGNORE_STACK
151 #define EXIT_IGNORE_STACK 0
154 #ifndef HAVE_epilogue
155 #define HAVE_epilogue 0
157 #ifndef HAVE_prologue
158 #define HAVE_prologue 0
160 #ifndef HAVE_sibcall_epilogue
161 #define HAVE_sibcall_epilogue 0
165 #define LOCAL_REGNO(REGNO) 0
167 #ifndef EPILOGUE_USES
168 #define EPILOGUE_USES(REGNO) 0
171 /* The obstack on which the flow graph components are allocated. */
173 struct obstack flow_obstack;
174 static char *flow_firstobj;
176 /* Number of basic blocks in the current function. */
180 /* Number of edges in the current function. */
184 /* The basic block array. */
186 varray_type basic_block_info;
188 /* The special entry and exit blocks. */
190 struct basic_block_def entry_exit_blocks[2]
195 NULL, /* local_set */
196 NULL, /* cond_local_set */
197 NULL, /* global_live_at_start */
198 NULL, /* global_live_at_end */
200 ENTRY_BLOCK, /* index */
202 -1, -1, /* eh_beg, eh_end */
210 NULL, /* local_set */
211 NULL, /* cond_local_set */
212 NULL, /* global_live_at_start */
213 NULL, /* global_live_at_end */
215 EXIT_BLOCK, /* index */
217 -1, -1, /* eh_beg, eh_end */
222 /* Nonzero if the second flow pass has completed. */
225 /* Maximum register number used in this function, plus one. */
229 /* Indexed by n, giving various register information */
231 varray_type reg_n_info;
233 /* Size of a regset for the current function,
234 in (1) bytes and (2) elements. */
239 /* Regset of regs live when calls to `setjmp'-like functions happen. */
240 /* ??? Does this exist only for the setjmp-clobbered warning message? */
242 regset regs_live_at_setjmp;
244 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
245 that have to go in the same hard reg.
246 The first two regs in the list are a pair, and the next two
247 are another pair, etc. */
250 /* Set of registers that may be eliminable. These are handled specially
251 in updating regs_ever_live. */
253 static HARD_REG_SET elim_reg_set;
255 /* The basic block structure for every insn, indexed by uid. */
257 varray_type basic_block_for_insn;
259 /* The labels mentioned in non-jump rtl. Valid during find_basic_blocks. */
260 /* ??? Should probably be using LABEL_NUSES instead. It would take a
261 bit of surgery to be able to use or co-opt the routines in jump. */
263 static rtx label_value_list;
264 static rtx tail_recursion_label_list;
266 /* Holds information for tracking conditional register life information. */
267 struct reg_cond_life_info
269 /* An EXPR_LIST of conditions under which a register is dead. */
272 /* ??? Could store mask of bytes that are dead, so that we could finally
273 track lifetimes of multi-word registers accessed via subregs. */
276 /* For use in communicating between propagate_block and its subroutines.
277 Holds all information needed to compute life and def-use information. */
279 struct propagate_block_info
281 /* The basic block we're considering. */
284 /* Bit N is set if register N is conditionally or unconditionally live. */
287 /* Bit N is set if register N is set this insn. */
290 /* Element N is the next insn that uses (hard or pseudo) register N
291 within the current basic block; or zero, if there is no such insn. */
294 /* Contains a list of all the MEMs we are tracking for dead store
298 /* If non-null, record the set of registers set unconditionally in the
302 /* If non-null, record the set of registers set conditionally in the
304 regset cond_local_set;
306 #ifdef HAVE_conditional_execution
307 /* Indexed by register number, holds a reg_cond_life_info for each
308 register that is not unconditionally live or dead. */
309 splay_tree reg_cond_dead;
311 /* Bit N is set if register N is in an expression in reg_cond_dead. */
315 /* Non-zero if the value of CC0 is live. */
318 /* Flags controling the set of information propagate_block collects. */
322 /* Store the data structures necessary for depth-first search. */
323 struct depth_first_search_dsS {
324 /* stack for backtracking during the algorithm */
327 /* number of edges in the stack. That is, positions 0, ..., sp-1
331 /* record of basic blocks already seen by depth-first search */
332 sbitmap visited_blocks;
334 typedef struct depth_first_search_dsS *depth_first_search_ds;
336 /* Forward declarations */
337 static int count_basic_blocks PARAMS ((rtx));
338 static void find_basic_blocks_1 PARAMS ((rtx));
339 static rtx find_label_refs PARAMS ((rtx, rtx));
340 static void clear_edges PARAMS ((void));
341 static void make_edges PARAMS ((rtx));
342 static void make_label_edge PARAMS ((sbitmap *, basic_block,
344 static void make_eh_edge PARAMS ((sbitmap *, eh_nesting_info *,
345 basic_block, rtx, int));
346 static void mark_critical_edges PARAMS ((void));
347 static void move_stray_eh_region_notes PARAMS ((void));
348 static void record_active_eh_regions PARAMS ((rtx));
350 static void commit_one_edge_insertion PARAMS ((edge));
352 static void delete_unreachable_blocks PARAMS ((void));
353 static void delete_eh_regions PARAMS ((void));
354 static int can_delete_note_p PARAMS ((rtx));
355 static void expunge_block PARAMS ((basic_block));
356 static int can_delete_label_p PARAMS ((rtx));
357 static int tail_recursion_label_p PARAMS ((rtx));
358 static int merge_blocks_move_predecessor_nojumps PARAMS ((basic_block,
360 static int merge_blocks_move_successor_nojumps PARAMS ((basic_block,
362 static int merge_blocks PARAMS ((edge,basic_block,basic_block));
363 static void try_merge_blocks PARAMS ((void));
364 static void tidy_fallthru_edges PARAMS ((void));
365 static int verify_wide_reg_1 PARAMS ((rtx *, void *));
366 static void verify_wide_reg PARAMS ((int, rtx, rtx));
367 static void verify_local_live_at_start PARAMS ((regset, basic_block));
368 static int set_noop_p PARAMS ((rtx));
369 static int noop_move_p PARAMS ((rtx));
370 static void delete_noop_moves PARAMS ((rtx));
371 static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
372 static void notice_stack_pointer_modification PARAMS ((rtx));
373 static void mark_reg PARAMS ((rtx, void *));
374 static void mark_regs_live_at_end PARAMS ((regset));
375 static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
376 static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
377 static void propagate_block_delete_insn PARAMS ((basic_block, rtx));
378 static rtx propagate_block_delete_libcall PARAMS ((basic_block, rtx, rtx));
379 static int insn_dead_p PARAMS ((struct propagate_block_info *,
381 static int libcall_dead_p PARAMS ((struct propagate_block_info *,
383 static void mark_set_regs PARAMS ((struct propagate_block_info *,
385 static void mark_set_1 PARAMS ((struct propagate_block_info *,
386 enum rtx_code, rtx, rtx,
388 #ifdef HAVE_conditional_execution
389 static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
391 static void free_reg_cond_life_info PARAMS ((splay_tree_value));
392 static int flush_reg_cond_reg_1 PARAMS ((splay_tree_node, void *));
393 static void flush_reg_cond_reg PARAMS ((struct propagate_block_info *,
395 static rtx elim_reg_cond PARAMS ((rtx, unsigned int));
396 static rtx ior_reg_cond PARAMS ((rtx, rtx, int));
397 static rtx not_reg_cond PARAMS ((rtx));
398 static rtx and_reg_cond PARAMS ((rtx, rtx, int));
401 static void attempt_auto_inc PARAMS ((struct propagate_block_info *,
402 rtx, rtx, rtx, rtx, rtx));
403 static void find_auto_inc PARAMS ((struct propagate_block_info *,
405 static int try_pre_increment_1 PARAMS ((struct propagate_block_info *,
407 static int try_pre_increment PARAMS ((rtx, rtx, HOST_WIDE_INT));
409 static void mark_used_reg PARAMS ((struct propagate_block_info *,
411 static void mark_used_regs PARAMS ((struct propagate_block_info *,
413 void dump_flow_info PARAMS ((FILE *));
414 void debug_flow_info PARAMS ((void));
415 static void dump_edge_info PARAMS ((FILE *, edge, int));
416 static void print_rtl_and_abort PARAMS ((void));
418 static void invalidate_mems_from_autoinc PARAMS ((struct propagate_block_info *,
420 static void invalidate_mems_from_set PARAMS ((struct propagate_block_info *,
422 static void remove_fake_successors PARAMS ((basic_block));
423 static void flow_nodes_print PARAMS ((const char *, const sbitmap,
425 static void flow_edge_list_print PARAMS ((const char *, const edge *,
427 static void flow_loops_cfg_dump PARAMS ((const struct loops *,
429 static int flow_loop_nested_p PARAMS ((struct loop *,
431 static int flow_loop_entry_edges_find PARAMS ((basic_block, const sbitmap,
433 static int flow_loop_exit_edges_find PARAMS ((const sbitmap, edge **));
434 static int flow_loop_nodes_find PARAMS ((basic_block, basic_block, sbitmap));
435 static int flow_depth_first_order_compute PARAMS ((int *, int *));
436 static void flow_dfs_compute_reverse_init
437 PARAMS ((depth_first_search_ds));
438 static void flow_dfs_compute_reverse_add_bb
439 PARAMS ((depth_first_search_ds, basic_block));
440 static basic_block flow_dfs_compute_reverse_execute
441 PARAMS ((depth_first_search_ds));
442 static void flow_dfs_compute_reverse_finish
443 PARAMS ((depth_first_search_ds));
444 static void flow_loop_pre_header_scan PARAMS ((struct loop *));
445 static basic_block flow_loop_pre_header_find PARAMS ((basic_block,
447 static void flow_loop_tree_node_add PARAMS ((struct loop *, struct loop *));
448 static void flow_loops_tree_build PARAMS ((struct loops *));
449 static int flow_loop_level_compute PARAMS ((struct loop *, int));
450 static int flow_loops_level_compute PARAMS ((struct loops *));
451 static void allocate_bb_life_data PARAMS ((void));
453 /* Find basic blocks of the current function.
454 F is the first insn of the function and NREGS the number of register
458 find_basic_blocks (f, nregs, file)
460 int nregs ATTRIBUTE_UNUSED;
461 FILE *file ATTRIBUTE_UNUSED;
465 /* Flush out existing data. */
466 if (basic_block_info != NULL)
472 /* Clear bb->aux on all extant basic blocks. We'll use this as a
473 tag for reuse during create_basic_block, just in case some pass
474 copies around basic block notes improperly. */
475 for (i = 0; i < n_basic_blocks; ++i)
476 BASIC_BLOCK (i)->aux = NULL;
478 VARRAY_FREE (basic_block_info);
481 n_basic_blocks = count_basic_blocks (f);
483 /* Size the basic block table. The actual structures will be allocated
484 by find_basic_blocks_1, since we want to keep the structure pointers
485 stable across calls to find_basic_blocks. */
486 /* ??? This whole issue would be much simpler if we called find_basic_blocks
487 exactly once, and thereafter we don't have a single long chain of
488 instructions at all until close to the end of compilation when we
489 actually lay them out. */
491 VARRAY_BB_INIT (basic_block_info, n_basic_blocks, "basic_block_info");
493 find_basic_blocks_1 (f);
495 /* Record the block to which an insn belongs. */
496 /* ??? This should be done another way, by which (perhaps) a label is
497 tagged directly with the basic block that it starts. It is used for
498 more than that currently, but IMO that is the only valid use. */
500 max_uid = get_max_uid ();
502 /* Leave space for insns life_analysis makes in some cases for auto-inc.
503 These cases are rare, so we don't need too much space. */
504 max_uid += max_uid / 10;
507 compute_bb_for_insn (max_uid);
509 /* Discover the edges of our cfg. */
510 record_active_eh_regions (f);
511 make_edges (label_value_list);
513 /* Do very simple cleanup now, for the benefit of code that runs between
514 here and cleanup_cfg, e.g. thread_prologue_and_epilogue_insns. */
515 tidy_fallthru_edges ();
517 mark_critical_edges ();
519 #ifdef ENABLE_CHECKING
525 check_function_return_warnings ()
527 if (warn_missing_noreturn
528 && !TREE_THIS_VOLATILE (cfun->decl)
529 && EXIT_BLOCK_PTR->pred == NULL)
530 warning ("function might be possible candidate for attribute `noreturn'");
532 /* If we have a path to EXIT, then we do return. */
533 if (TREE_THIS_VOLATILE (cfun->decl)
534 && EXIT_BLOCK_PTR->pred != NULL)
535 warning ("`noreturn' function does return");
537 /* If the clobber_return_insn appears in some basic block, then we
538 do reach the end without returning a value. */
539 else if (warn_return_type
540 && cfun->x_clobber_return_insn != NULL
541 && EXIT_BLOCK_PTR->pred != NULL)
543 int max_uid = get_max_uid ();
545 /* If clobber_return_insn was excised by jump1, then renumber_insns
546 can make max_uid smaller than the number still recorded in our rtx.
547 That's fine, since this is a quick way of verifying that the insn
548 is no longer in the chain. */
549 if (INSN_UID (cfun->x_clobber_return_insn) < max_uid)
551 /* Recompute insn->block mapping, since the initial mapping is
552 set before we delete unreachable blocks. */
553 compute_bb_for_insn (max_uid);
555 if (BLOCK_FOR_INSN (cfun->x_clobber_return_insn) != NULL)
556 warning ("control reaches end of non-void function");
561 /* Count the basic blocks of the function. */
564 count_basic_blocks (f)
568 register RTX_CODE prev_code;
569 register int count = 0;
571 int call_had_abnormal_edge = 0;
573 prev_code = JUMP_INSN;
574 for (insn = f; insn; insn = NEXT_INSN (insn))
576 register RTX_CODE code = GET_CODE (insn);
578 if (code == CODE_LABEL
579 || (GET_RTX_CLASS (code) == 'i'
580 && (prev_code == JUMP_INSN
581 || prev_code == BARRIER
582 || (prev_code == CALL_INSN && call_had_abnormal_edge))))
585 /* Record whether this call created an edge. */
586 if (code == CALL_INSN)
588 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
589 int region = (note ? INTVAL (XEXP (note, 0)) : 1);
591 call_had_abnormal_edge = 0;
593 /* If there is an EH region or rethrow, we have an edge. */
594 if ((eh_region && region > 0)
595 || find_reg_note (insn, REG_EH_RETHROW, NULL_RTX))
596 call_had_abnormal_edge = 1;
597 else if (nonlocal_goto_handler_labels && region >= 0)
598 /* If there is a nonlocal goto label and the specified
599 region number isn't -1, we have an edge. (0 means
600 no throw, but might have a nonlocal goto). */
601 call_had_abnormal_edge = 1;
606 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
608 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
612 /* The rest of the compiler works a bit smoother when we don't have to
613 check for the edge case of do-nothing functions with no basic blocks. */
616 emit_insn (gen_rtx_USE (VOIDmode, const0_rtx));
623 /* Scan a list of insns for labels referred to other than by jumps.
624 This is used to scan the alternatives of a call placeholder. */
626 find_label_refs (f, lvl)
632 for (insn = f; insn; insn = NEXT_INSN (insn))
637 /* Make a list of all labels referred to other than by jumps
638 (which just don't have the REG_LABEL notes).
640 Make a special exception for labels followed by an ADDR*VEC,
641 as this would be a part of the tablejump setup code.
643 Make a special exception for the eh_return_stub_label, which
644 we know isn't part of any otherwise visible control flow. */
646 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
647 if (REG_NOTE_KIND (note) == REG_LABEL)
649 rtx lab = XEXP (note, 0), next;
651 if (lab == eh_return_stub_label)
653 else if ((next = next_nonnote_insn (lab)) != NULL
654 && GET_CODE (next) == JUMP_INSN
655 && (GET_CODE (PATTERN (next)) == ADDR_VEC
656 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
658 else if (GET_CODE (lab) == NOTE)
661 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
668 /* Find all basic blocks of the function whose first insn is F.
670 Collect and return a list of labels whose addresses are taken. This
671 will be used in make_edges for use with computed gotos. */
674 find_basic_blocks_1 (f)
677 register rtx insn, next;
679 rtx bb_note = NULL_RTX;
680 rtx eh_list = NULL_RTX;
686 /* We process the instructions in a slightly different way than we did
687 previously. This is so that we see a NOTE_BASIC_BLOCK after we have
688 closed out the previous block, so that it gets attached at the proper
689 place. Since this form should be equivalent to the previous,
690 count_basic_blocks continues to use the old form as a check. */
692 for (insn = f; insn; insn = next)
694 enum rtx_code code = GET_CODE (insn);
696 next = NEXT_INSN (insn);
702 int kind = NOTE_LINE_NUMBER (insn);
704 /* Keep a LIFO list of the currently active exception notes. */
705 if (kind == NOTE_INSN_EH_REGION_BEG)
706 eh_list = alloc_INSN_LIST (insn, eh_list);
707 else if (kind == NOTE_INSN_EH_REGION_END)
711 eh_list = XEXP (eh_list, 1);
712 free_INSN_LIST_node (t);
715 /* Look for basic block notes with which to keep the
716 basic_block_info pointers stable. Unthread the note now;
717 we'll put it back at the right place in create_basic_block.
718 Or not at all if we've already found a note in this block. */
719 else if (kind == NOTE_INSN_BASIC_BLOCK)
721 if (bb_note == NULL_RTX)
724 next = flow_delete_insn (insn);
730 /* A basic block starts at a label. If we've closed one off due
731 to a barrier or some such, no need to do it again. */
732 if (head != NULL_RTX)
734 /* While we now have edge lists with which other portions of
735 the compiler might determine a call ending a basic block
736 does not imply an abnormal edge, it will be a bit before
737 everything can be updated. So continue to emit a noop at
738 the end of such a block. */
739 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
741 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
742 end = emit_insn_after (nop, end);
745 create_basic_block (i++, head, end, bb_note);
753 /* A basic block ends at a jump. */
754 if (head == NULL_RTX)
758 /* ??? Make a special check for table jumps. The way this
759 happens is truly and amazingly gross. We are about to
760 create a basic block that contains just a code label and
761 an addr*vec jump insn. Worse, an addr_diff_vec creates
762 its own natural loop.
764 Prevent this bit of brain damage, pasting things together
765 correctly in make_edges.
767 The correct solution involves emitting the table directly
768 on the tablejump instruction as a note, or JUMP_LABEL. */
770 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
771 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
779 goto new_bb_inclusive;
782 /* A basic block ends at a barrier. It may be that an unconditional
783 jump already closed the basic block -- no need to do it again. */
784 if (head == NULL_RTX)
787 /* While we now have edge lists with which other portions of the
788 compiler might determine a call ending a basic block does not
789 imply an abnormal edge, it will be a bit before everything can
790 be updated. So continue to emit a noop at the end of such a
792 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
794 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
795 end = emit_insn_after (nop, end);
797 goto new_bb_exclusive;
801 /* Record whether this call created an edge. */
802 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
803 int region = (note ? INTVAL (XEXP (note, 0)) : 1);
804 int call_has_abnormal_edge = 0;
806 if (GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
808 /* Scan each of the alternatives for label refs. */
809 lvl = find_label_refs (XEXP (PATTERN (insn), 0), lvl);
810 lvl = find_label_refs (XEXP (PATTERN (insn), 1), lvl);
811 lvl = find_label_refs (XEXP (PATTERN (insn), 2), lvl);
812 /* Record its tail recursion label, if any. */
813 if (XEXP (PATTERN (insn), 3) != NULL_RTX)
814 trll = alloc_EXPR_LIST (0, XEXP (PATTERN (insn), 3), trll);
817 /* If there is an EH region or rethrow, we have an edge. */
818 if ((eh_list && region > 0)
819 || find_reg_note (insn, REG_EH_RETHROW, NULL_RTX))
820 call_has_abnormal_edge = 1;
821 else if (nonlocal_goto_handler_labels && region >= 0)
822 /* If there is a nonlocal goto label and the specified
823 region number isn't -1, we have an edge. (0 means
824 no throw, but might have a nonlocal goto). */
825 call_has_abnormal_edge = 1;
827 /* A basic block ends at a call that can either throw or
828 do a non-local goto. */
829 if (call_has_abnormal_edge)
832 if (head == NULL_RTX)
837 create_basic_block (i++, head, end, bb_note);
838 head = end = NULL_RTX;
846 if (GET_RTX_CLASS (code) == 'i')
848 if (head == NULL_RTX)
855 if (GET_RTX_CLASS (code) == 'i')
859 /* Make a list of all labels referred to other than by jumps
860 (which just don't have the REG_LABEL notes).
862 Make a special exception for labels followed by an ADDR*VEC,
863 as this would be a part of the tablejump setup code.
865 Make a special exception for the eh_return_stub_label, which
866 we know isn't part of any otherwise visible control flow. */
868 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
869 if (REG_NOTE_KIND (note) == REG_LABEL)
871 rtx lab = XEXP (note, 0), next;
873 if (lab == eh_return_stub_label)
875 else if ((next = next_nonnote_insn (lab)) != NULL
876 && GET_CODE (next) == JUMP_INSN
877 && (GET_CODE (PATTERN (next)) == ADDR_VEC
878 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
880 else if (GET_CODE (lab) == NOTE)
883 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
888 if (head != NULL_RTX)
889 create_basic_block (i++, head, end, bb_note);
891 flow_delete_insn (bb_note);
893 if (i != n_basic_blocks)
896 label_value_list = lvl;
897 tail_recursion_label_list = trll;
900 /* Tidy the CFG by deleting unreachable code and whatnot. */
906 delete_unreachable_blocks ();
907 move_stray_eh_region_notes ();
908 record_active_eh_regions (f);
910 mark_critical_edges ();
912 /* Kill the data we won't maintain. */
913 free_EXPR_LIST_list (&label_value_list);
914 free_EXPR_LIST_list (&tail_recursion_label_list);
917 /* Create a new basic block consisting of the instructions between
918 HEAD and END inclusive. Reuses the note and basic block struct
919 in BB_NOTE, if any. */
922 create_basic_block (index, head, end, bb_note)
924 rtx head, end, bb_note;
929 && ! RTX_INTEGRATED_P (bb_note)
930 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
933 /* If we found an existing note, thread it back onto the chain. */
937 if (GET_CODE (head) == CODE_LABEL)
941 after = PREV_INSN (head);
945 if (after != bb_note && NEXT_INSN (after) != bb_note)
946 reorder_insns (bb_note, bb_note, after);
950 /* Otherwise we must create a note and a basic block structure.
951 Since we allow basic block structs in rtl, give the struct
952 the same lifetime by allocating it off the function obstack
953 rather than using malloc. */
955 bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*bb));
956 memset (bb, 0, sizeof (*bb));
958 if (GET_CODE (head) == CODE_LABEL)
959 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
962 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
965 NOTE_BASIC_BLOCK (bb_note) = bb;
968 /* Always include the bb note in the block. */
969 if (NEXT_INSN (end) == bb_note)
975 BASIC_BLOCK (index) = bb;
977 /* Tag the block so that we know it has been used when considering
978 other basic block notes. */
982 /* Records the basic block struct in BB_FOR_INSN, for every instruction
983 indexed by INSN_UID. MAX is the size of the array. */
986 compute_bb_for_insn (max)
991 if (basic_block_for_insn)
992 VARRAY_FREE (basic_block_for_insn);
993 VARRAY_BB_INIT (basic_block_for_insn, max, "basic_block_for_insn");
995 for (i = 0; i < n_basic_blocks; ++i)
997 basic_block bb = BASIC_BLOCK (i);
1004 int uid = INSN_UID (insn);
1006 VARRAY_BB (basic_block_for_insn, uid) = bb;
1009 insn = NEXT_INSN (insn);
1014 /* Free the memory associated with the edge structures. */
1022 for (i = 0; i < n_basic_blocks; ++i)
1024 basic_block bb = BASIC_BLOCK (i);
1026 for (e = bb->succ; e; e = n)
1036 for (e = ENTRY_BLOCK_PTR->succ; e; e = n)
1042 ENTRY_BLOCK_PTR->succ = 0;
1043 EXIT_BLOCK_PTR->pred = 0;
1048 /* Identify the edges between basic blocks.
1050 NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks
1051 that are otherwise unreachable may be reachable with a non-local goto.
1053 BB_EH_END is an array indexed by basic block number in which we record
1054 the list of exception regions active at the end of the basic block. */
1057 make_edges (label_value_list)
1058 rtx label_value_list;
1061 eh_nesting_info *eh_nest_info = init_eh_nesting_info ();
1062 sbitmap *edge_cache = NULL;
1064 /* Assume no computed jump; revise as we create edges. */
1065 current_function_has_computed_jump = 0;
1067 /* Heavy use of computed goto in machine-generated code can lead to
1068 nearly fully-connected CFGs. In that case we spend a significant
1069 amount of time searching the edge lists for duplicates. */
1070 if (forced_labels || label_value_list)
1072 edge_cache = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
1073 sbitmap_vector_zero (edge_cache, n_basic_blocks);
1076 /* By nature of the way these get numbered, block 0 is always the entry. */
1077 make_edge (edge_cache, ENTRY_BLOCK_PTR, BASIC_BLOCK (0), EDGE_FALLTHRU);
1079 for (i = 0; i < n_basic_blocks; ++i)
1081 basic_block bb = BASIC_BLOCK (i);
1084 int force_fallthru = 0;
1086 /* Examine the last instruction of the block, and discover the
1087 ways we can leave the block. */
1090 code = GET_CODE (insn);
1093 if (code == JUMP_INSN)
1097 /* Recognize a non-local goto as a branch outside the
1098 current function. */
1099 if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX))
1102 /* ??? Recognize a tablejump and do the right thing. */
1103 else if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1104 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1105 && GET_CODE (tmp) == JUMP_INSN
1106 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1107 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1112 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1113 vec = XVEC (PATTERN (tmp), 0);
1115 vec = XVEC (PATTERN (tmp), 1);
1117 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1118 make_label_edge (edge_cache, bb,
1119 XEXP (RTVEC_ELT (vec, j), 0), 0);
1121 /* Some targets (eg, ARM) emit a conditional jump that also
1122 contains the out-of-range target. Scan for these and
1123 add an edge if necessary. */
1124 if ((tmp = single_set (insn)) != NULL
1125 && SET_DEST (tmp) == pc_rtx
1126 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1127 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF)
1128 make_label_edge (edge_cache, bb,
1129 XEXP (XEXP (SET_SRC (tmp), 2), 0), 0);
1131 #ifdef CASE_DROPS_THROUGH
1132 /* Silly VAXen. The ADDR_VEC is going to be in the way of
1133 us naturally detecting fallthru into the next block. */
1138 /* If this is a computed jump, then mark it as reaching
1139 everything on the label_value_list and forced_labels list. */
1140 else if (computed_jump_p (insn))
1142 current_function_has_computed_jump = 1;
1144 for (x = label_value_list; x; x = XEXP (x, 1))
1145 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1147 for (x = forced_labels; x; x = XEXP (x, 1))
1148 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1151 /* Returns create an exit out. */
1152 else if (returnjump_p (insn))
1153 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, 0);
1155 /* Otherwise, we have a plain conditional or unconditional jump. */
1158 if (! JUMP_LABEL (insn))
1160 make_label_edge (edge_cache, bb, JUMP_LABEL (insn), 0);
1164 /* If this is a sibling call insn, then this is in effect a
1165 combined call and return, and so we need an edge to the
1166 exit block. No need to worry about EH edges, since we
1167 wouldn't have created the sibling call in the first place. */
1169 if (code == CALL_INSN && SIBLING_CALL_P (insn))
1170 make_edge (edge_cache, bb, EXIT_BLOCK_PTR,
1171 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1173 /* If this is a CALL_INSN, then mark it as reaching the active EH
1174 handler for this CALL_INSN. If we're handling asynchronous
1175 exceptions then any insn can reach any of the active handlers.
1177 Also mark the CALL_INSN as reaching any nonlocal goto handler. */
1179 else if (code == CALL_INSN || asynchronous_exceptions)
1181 /* Add any appropriate EH edges. We do this unconditionally
1182 since there may be a REG_EH_REGION or REG_EH_RETHROW note
1183 on the call, and this needn't be within an EH region. */
1184 make_eh_edge (edge_cache, eh_nest_info, bb, insn, bb->eh_end);
1186 /* If we have asynchronous exceptions, do the same for *all*
1187 exception regions active in the block. */
1188 if (asynchronous_exceptions
1189 && bb->eh_beg != bb->eh_end)
1191 if (bb->eh_beg >= 0)
1192 make_eh_edge (edge_cache, eh_nest_info, bb,
1193 NULL_RTX, bb->eh_beg);
1195 for (x = bb->head; x != bb->end; x = NEXT_INSN (x))
1196 if (GET_CODE (x) == NOTE
1197 && (NOTE_LINE_NUMBER (x) == NOTE_INSN_EH_REGION_BEG
1198 || NOTE_LINE_NUMBER (x) == NOTE_INSN_EH_REGION_END))
1200 int region = NOTE_EH_HANDLER (x);
1201 make_eh_edge (edge_cache, eh_nest_info, bb,
1206 if (code == CALL_INSN && nonlocal_goto_handler_labels)
1208 /* ??? This could be made smarter: in some cases it's possible
1209 to tell that certain calls will not do a nonlocal goto.
1211 For example, if the nested functions that do the nonlocal
1212 gotos do not have their addresses taken, then only calls to
1213 those functions or to other nested functions that use them
1214 could possibly do nonlocal gotos. */
1215 /* We do know that a REG_EH_REGION note with a value less
1216 than 0 is guaranteed not to perform a non-local goto. */
1217 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
1218 if (!note || INTVAL (XEXP (note, 0)) >= 0)
1219 for (x = nonlocal_goto_handler_labels; x; x = XEXP (x, 1))
1220 make_label_edge (edge_cache, bb, XEXP (x, 0),
1221 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1225 /* We know something about the structure of the function __throw in
1226 libgcc2.c. It is the only function that ever contains eh_stub
1227 labels. It modifies its return address so that the last block
1228 returns to one of the eh_stub labels within it. So we have to
1229 make additional edges in the flow graph. */
1230 if (i + 1 == n_basic_blocks && eh_return_stub_label != 0)
1231 make_label_edge (edge_cache, bb, eh_return_stub_label, EDGE_EH);
1233 /* Find out if we can drop through to the next block. */
1234 insn = next_nonnote_insn (insn);
1235 if (!insn || (i + 1 == n_basic_blocks && force_fallthru))
1236 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU);
1237 else if (i + 1 < n_basic_blocks)
1239 rtx tmp = BLOCK_HEAD (i + 1);
1240 if (GET_CODE (tmp) == NOTE)
1241 tmp = next_nonnote_insn (tmp);
1242 if (force_fallthru || insn == tmp)
1243 make_edge (edge_cache, bb, BASIC_BLOCK (i + 1), EDGE_FALLTHRU);
1247 free_eh_nesting_info (eh_nest_info);
1249 sbitmap_vector_free (edge_cache);
1252 /* Create an edge between two basic blocks. FLAGS are auxiliary information
1253 about the edge that is accumulated between calls. */
1256 make_edge (edge_cache, src, dst, flags)
1257 sbitmap *edge_cache;
1258 basic_block src, dst;
1264 /* Don't bother with edge cache for ENTRY or EXIT; there aren't that
1265 many edges to them, and we didn't allocate memory for it. */
1266 use_edge_cache = (edge_cache
1267 && src != ENTRY_BLOCK_PTR
1268 && dst != EXIT_BLOCK_PTR);
1270 /* Make sure we don't add duplicate edges. */
1271 switch (use_edge_cache)
1274 /* Quick test for non-existance of the edge. */
1275 if (! TEST_BIT (edge_cache[src->index], dst->index))
1278 /* The edge exists; early exit if no work to do. */
1284 for (e = src->succ; e; e = e->succ_next)
1293 e = (edge) xcalloc (1, sizeof (*e));
1296 e->succ_next = src->succ;
1297 e->pred_next = dst->pred;
1306 SET_BIT (edge_cache[src->index], dst->index);
1309 /* Create an edge from a basic block to a label. */
1312 make_label_edge (edge_cache, src, label, flags)
1313 sbitmap *edge_cache;
1318 if (GET_CODE (label) != CODE_LABEL)
1321 /* If the label was never emitted, this insn is junk, but avoid a
1322 crash trying to refer to BLOCK_FOR_INSN (label). This can happen
1323 as a result of a syntax error and a diagnostic has already been
1326 if (INSN_UID (label) == 0)
1329 make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags);
1332 /* Create the edges generated by INSN in REGION. */
1335 make_eh_edge (edge_cache, eh_nest_info, src, insn, region)
1336 sbitmap *edge_cache;
1337 eh_nesting_info *eh_nest_info;
1342 handler_info **handler_list;
1345 is_call = (insn && GET_CODE (insn) == CALL_INSN ? EDGE_ABNORMAL_CALL : 0);
1346 num = reachable_handlers (region, eh_nest_info, insn, &handler_list);
1349 make_label_edge (edge_cache, src, handler_list[num]->handler_label,
1350 EDGE_ABNORMAL | EDGE_EH | is_call);
1354 /* EH_REGION notes appearing between basic blocks is ambiguous, and even
1355 dangerous if we intend to move basic blocks around. Move such notes
1356 into the following block. */
1359 move_stray_eh_region_notes ()
1364 if (n_basic_blocks < 2)
1367 b2 = BASIC_BLOCK (n_basic_blocks - 1);
1368 for (i = n_basic_blocks - 2; i >= 0; --i, b2 = b1)
1370 rtx insn, next, list = NULL_RTX;
1372 b1 = BASIC_BLOCK (i);
1373 for (insn = NEXT_INSN (b1->end); insn != b2->head; insn = next)
1375 next = NEXT_INSN (insn);
1376 if (GET_CODE (insn) == NOTE
1377 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG
1378 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
1380 /* Unlink from the insn chain. */
1381 NEXT_INSN (PREV_INSN (insn)) = next;
1382 PREV_INSN (next) = PREV_INSN (insn);
1385 NEXT_INSN (insn) = list;
1390 if (list == NULL_RTX)
1393 /* Find where to insert these things. */
1395 if (GET_CODE (insn) == CODE_LABEL)
1396 insn = NEXT_INSN (insn);
1400 next = NEXT_INSN (list);
1401 add_insn_after (list, insn);
1407 /* Recompute eh_beg/eh_end for each basic block. */
1410 record_active_eh_regions (f)
1413 rtx insn, eh_list = NULL_RTX;
1415 basic_block bb = BASIC_BLOCK (0);
1417 for (insn = f; insn; insn = NEXT_INSN (insn))
1419 if (bb->head == insn)
1420 bb->eh_beg = (eh_list ? NOTE_EH_HANDLER (XEXP (eh_list, 0)) : -1);
1422 if (GET_CODE (insn) == NOTE)
1424 int kind = NOTE_LINE_NUMBER (insn);
1425 if (kind == NOTE_INSN_EH_REGION_BEG)
1426 eh_list = alloc_INSN_LIST (insn, eh_list);
1427 else if (kind == NOTE_INSN_EH_REGION_END)
1429 rtx t = XEXP (eh_list, 1);
1430 free_INSN_LIST_node (eh_list);
1435 if (bb->end == insn)
1437 bb->eh_end = (eh_list ? NOTE_EH_HANDLER (XEXP (eh_list, 0)) : -1);
1439 if (i == n_basic_blocks)
1441 bb = BASIC_BLOCK (i);
1446 /* Identify critical edges and set the bits appropriately. */
1449 mark_critical_edges ()
1451 int i, n = n_basic_blocks;
1454 /* We begin with the entry block. This is not terribly important now,
1455 but could be if a front end (Fortran) implemented alternate entry
1457 bb = ENTRY_BLOCK_PTR;
1464 /* (1) Critical edges must have a source with multiple successors. */
1465 if (bb->succ && bb->succ->succ_next)
1467 for (e = bb->succ; e; e = e->succ_next)
1469 /* (2) Critical edges must have a destination with multiple
1470 predecessors. Note that we know there is at least one
1471 predecessor -- the edge we followed to get here. */
1472 if (e->dest->pred->pred_next)
1473 e->flags |= EDGE_CRITICAL;
1475 e->flags &= ~EDGE_CRITICAL;
1480 for (e = bb->succ; e; e = e->succ_next)
1481 e->flags &= ~EDGE_CRITICAL;
1486 bb = BASIC_BLOCK (i);
1490 /* Split a block BB after insn INSN creating a new fallthru edge.
1491 Return the new edge. Note that to keep other parts of the compiler happy,
1492 this function renumbers all the basic blocks so that the new
1493 one has a number one greater than the block split. */
1496 split_block (bb, insn)
1506 /* There is no point splitting the block after its end. */
1507 if (bb->end == insn)
1510 /* Create the new structures. */
1511 new_bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*new_bb));
1512 new_edge = (edge) xcalloc (1, sizeof (*new_edge));
1515 memset (new_bb, 0, sizeof (*new_bb));
1517 new_bb->head = NEXT_INSN (insn);
1518 new_bb->end = bb->end;
1521 new_bb->succ = bb->succ;
1522 bb->succ = new_edge;
1523 new_bb->pred = new_edge;
1524 new_bb->count = bb->count;
1525 new_bb->loop_depth = bb->loop_depth;
1528 new_edge->dest = new_bb;
1529 new_edge->flags = EDGE_FALLTHRU;
1530 new_edge->probability = REG_BR_PROB_BASE;
1531 new_edge->count = bb->count;
1533 /* Redirect the src of the successor edges of bb to point to new_bb. */
1534 for (e = new_bb->succ; e; e = e->succ_next)
1537 /* Place the new block just after the block being split. */
1538 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
1540 /* Some parts of the compiler expect blocks to be number in
1541 sequential order so insert the new block immediately after the
1542 block being split.. */
1544 for (i = n_basic_blocks - 1; i > j + 1; --i)
1546 basic_block tmp = BASIC_BLOCK (i - 1);
1547 BASIC_BLOCK (i) = tmp;
1551 BASIC_BLOCK (i) = new_bb;
1554 /* Create the basic block note. */
1555 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
1557 NOTE_BASIC_BLOCK (bb_note) = new_bb;
1558 new_bb->head = bb_note;
1560 update_bb_for_insn (new_bb);
1562 if (bb->global_live_at_start)
1564 new_bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1565 new_bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1566 COPY_REG_SET (new_bb->global_live_at_end, bb->global_live_at_end);
1568 /* We now have to calculate which registers are live at the end
1569 of the split basic block and at the start of the new basic
1570 block. Start with those registers that are known to be live
1571 at the end of the original basic block and get
1572 propagate_block to determine which registers are live. */
1573 COPY_REG_SET (new_bb->global_live_at_start, bb->global_live_at_end);
1574 propagate_block (new_bb, new_bb->global_live_at_start, NULL, NULL, 0);
1575 COPY_REG_SET (bb->global_live_at_end,
1576 new_bb->global_live_at_start);
1583 /* Split a (typically critical) edge. Return the new block.
1584 Abort on abnormal edges.
1586 ??? The code generally expects to be called on critical edges.
1587 The case of a block ending in an unconditional jump to a
1588 block with multiple predecessors is not handled optimally. */
1591 split_edge (edge_in)
1594 basic_block old_pred, bb, old_succ;
1599 /* Abnormal edges cannot be split. */
1600 if ((edge_in->flags & EDGE_ABNORMAL) != 0)
1603 old_pred = edge_in->src;
1604 old_succ = edge_in->dest;
1606 /* Remove the existing edge from the destination's pred list. */
1609 for (pp = &old_succ->pred; *pp != edge_in; pp = &(*pp)->pred_next)
1611 *pp = edge_in->pred_next;
1612 edge_in->pred_next = NULL;
1615 /* Create the new structures. */
1616 bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*bb));
1617 edge_out = (edge) xcalloc (1, sizeof (*edge_out));
1620 memset (bb, 0, sizeof (*bb));
1622 /* ??? This info is likely going to be out of date very soon. */
1623 if (old_succ->global_live_at_start)
1625 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1626 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1627 COPY_REG_SET (bb->global_live_at_start, old_succ->global_live_at_start);
1628 COPY_REG_SET (bb->global_live_at_end, old_succ->global_live_at_start);
1633 bb->succ = edge_out;
1634 bb->count = edge_in->count;
1637 edge_in->flags &= ~EDGE_CRITICAL;
1639 edge_out->pred_next = old_succ->pred;
1640 edge_out->succ_next = NULL;
1642 edge_out->dest = old_succ;
1643 edge_out->flags = EDGE_FALLTHRU;
1644 edge_out->probability = REG_BR_PROB_BASE;
1645 edge_out->count = edge_in->count;
1647 old_succ->pred = edge_out;
1649 /* Tricky case -- if there existed a fallthru into the successor
1650 (and we're not it) we must add a new unconditional jump around
1651 the new block we're actually interested in.
1653 Further, if that edge is critical, this means a second new basic
1654 block must be created to hold it. In order to simplify correct
1655 insn placement, do this before we touch the existing basic block
1656 ordering for the block we were really wanting. */
1657 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1660 for (e = edge_out->pred_next; e; e = e->pred_next)
1661 if (e->flags & EDGE_FALLTHRU)
1666 basic_block jump_block;
1669 if ((e->flags & EDGE_CRITICAL) == 0
1670 && e->src != ENTRY_BLOCK_PTR)
1672 /* Non critical -- we can simply add a jump to the end
1673 of the existing predecessor. */
1674 jump_block = e->src;
1678 /* We need a new block to hold the jump. The simplest
1679 way to do the bulk of the work here is to recursively
1681 jump_block = split_edge (e);
1682 e = jump_block->succ;
1685 /* Now add the jump insn ... */
1686 pos = emit_jump_insn_after (gen_jump (old_succ->head),
1688 jump_block->end = pos;
1689 if (basic_block_for_insn)
1690 set_block_for_insn (pos, jump_block);
1691 emit_barrier_after (pos);
1693 /* ... let jump know that label is in use, ... */
1694 JUMP_LABEL (pos) = old_succ->head;
1695 ++LABEL_NUSES (old_succ->head);
1697 /* ... and clear fallthru on the outgoing edge. */
1698 e->flags &= ~EDGE_FALLTHRU;
1700 /* Continue splitting the interesting edge. */
1704 /* Place the new block just in front of the successor. */
1705 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
1706 if (old_succ == EXIT_BLOCK_PTR)
1707 j = n_basic_blocks - 1;
1709 j = old_succ->index;
1710 for (i = n_basic_blocks - 1; i > j; --i)
1712 basic_block tmp = BASIC_BLOCK (i - 1);
1713 BASIC_BLOCK (i) = tmp;
1716 BASIC_BLOCK (i) = bb;
1719 /* Create the basic block note.
1721 Where we place the note can have a noticable impact on the generated
1722 code. Consider this cfg:
1732 If we need to insert an insn on the edge from block 0 to block 1,
1733 we want to ensure the instructions we insert are outside of any
1734 loop notes that physically sit between block 0 and block 1. Otherwise
1735 we confuse the loop optimizer into thinking the loop is a phony. */
1736 if (old_succ != EXIT_BLOCK_PTR
1737 && PREV_INSN (old_succ->head)
1738 && GET_CODE (PREV_INSN (old_succ->head)) == NOTE
1739 && NOTE_LINE_NUMBER (PREV_INSN (old_succ->head)) == NOTE_INSN_LOOP_BEG)
1740 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
1741 PREV_INSN (old_succ->head));
1742 else if (old_succ != EXIT_BLOCK_PTR)
1743 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, old_succ->head);
1745 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
1746 NOTE_BASIC_BLOCK (bb_note) = bb;
1747 bb->head = bb->end = bb_note;
1749 /* Not quite simple -- for non-fallthru edges, we must adjust the
1750 predecessor's jump instruction to target our new block. */
1751 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1753 rtx tmp, insn = old_pred->end;
1754 rtx old_label = old_succ->head;
1755 rtx new_label = gen_label_rtx ();
1757 if (GET_CODE (insn) != JUMP_INSN)
1760 /* ??? Recognize a tablejump and adjust all matching cases. */
1761 if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1762 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1763 && GET_CODE (tmp) == JUMP_INSN
1764 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1765 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1770 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1771 vec = XVEC (PATTERN (tmp), 0);
1773 vec = XVEC (PATTERN (tmp), 1);
1775 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1776 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
1778 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (VOIDmode, new_label);
1779 --LABEL_NUSES (old_label);
1780 ++LABEL_NUSES (new_label);
1783 /* Handle casesi dispatch insns */
1784 if ((tmp = single_set (insn)) != NULL
1785 && SET_DEST (tmp) == pc_rtx
1786 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1787 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
1788 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
1790 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (VOIDmode,
1792 --LABEL_NUSES (old_label);
1793 ++LABEL_NUSES (new_label);
1798 /* This would have indicated an abnormal edge. */
1799 if (computed_jump_p (insn))
1802 /* A return instruction can't be redirected. */
1803 if (returnjump_p (insn))
1806 /* If the insn doesn't go where we think, we're confused. */
1807 if (JUMP_LABEL (insn) != old_label)
1810 redirect_jump (insn, new_label, 0);
1813 emit_label_before (new_label, bb_note);
1814 bb->head = new_label;
1820 /* Queue instructions for insertion on an edge between two basic blocks.
1821 The new instructions and basic blocks (if any) will not appear in the
1822 CFG until commit_edge_insertions is called. */
1825 insert_insn_on_edge (pattern, e)
1829 /* We cannot insert instructions on an abnormal critical edge.
1830 It will be easier to find the culprit if we die now. */
1831 if ((e->flags & (EDGE_ABNORMAL|EDGE_CRITICAL))
1832 == (EDGE_ABNORMAL|EDGE_CRITICAL))
1835 if (e->insns == NULL_RTX)
1838 push_to_sequence (e->insns);
1840 emit_insn (pattern);
1842 e->insns = get_insns ();
1846 /* Update the CFG for the instructions queued on edge E. */
1849 commit_one_edge_insertion (e)
1852 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
1855 /* Pull the insns off the edge now since the edge might go away. */
1857 e->insns = NULL_RTX;
1859 /* Figure out where to put these things. If the destination has
1860 one predecessor, insert there. Except for the exit block. */
1861 if (e->dest->pred->pred_next == NULL
1862 && e->dest != EXIT_BLOCK_PTR)
1866 /* Get the location correct wrt a code label, and "nice" wrt
1867 a basic block note, and before everything else. */
1869 if (GET_CODE (tmp) == CODE_LABEL)
1870 tmp = NEXT_INSN (tmp);
1871 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
1872 tmp = NEXT_INSN (tmp);
1873 if (tmp == bb->head)
1876 after = PREV_INSN (tmp);
1879 /* If the source has one successor and the edge is not abnormal,
1880 insert there. Except for the entry block. */
1881 else if ((e->flags & EDGE_ABNORMAL) == 0
1882 && e->src->succ->succ_next == NULL
1883 && e->src != ENTRY_BLOCK_PTR)
1886 /* It is possible to have a non-simple jump here. Consider a target
1887 where some forms of unconditional jumps clobber a register. This
1888 happens on the fr30 for example.
1890 We know this block has a single successor, so we can just emit
1891 the queued insns before the jump. */
1892 if (GET_CODE (bb->end) == JUMP_INSN)
1898 /* We'd better be fallthru, or we've lost track of what's what. */
1899 if ((e->flags & EDGE_FALLTHRU) == 0)
1906 /* Otherwise we must split the edge. */
1909 bb = split_edge (e);
1913 /* Now that we've found the spot, do the insertion. */
1915 /* Set the new block number for these insns, if structure is allocated. */
1916 if (basic_block_for_insn)
1919 for (i = insns; i != NULL_RTX; i = NEXT_INSN (i))
1920 set_block_for_insn (i, bb);
1925 emit_insns_before (insns, before);
1926 if (before == bb->head)
1929 last = prev_nonnote_insn (before);
1933 last = emit_insns_after (insns, after);
1934 if (after == bb->end)
1938 if (returnjump_p (last))
1940 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1941 This is not currently a problem because this only happens
1942 for the (single) epilogue, which already has a fallthru edge
1946 if (e->dest != EXIT_BLOCK_PTR
1947 || e->succ_next != NULL
1948 || (e->flags & EDGE_FALLTHRU) == 0)
1950 e->flags &= ~EDGE_FALLTHRU;
1952 emit_barrier_after (last);
1956 flow_delete_insn (before);
1958 else if (GET_CODE (last) == JUMP_INSN)
1962 /* Update the CFG for all queued instructions. */
1965 commit_edge_insertions ()
1970 #ifdef ENABLE_CHECKING
1971 verify_flow_info ();
1975 bb = ENTRY_BLOCK_PTR;
1980 for (e = bb->succ; e; e = next)
1982 next = e->succ_next;
1984 commit_one_edge_insertion (e);
1987 if (++i >= n_basic_blocks)
1989 bb = BASIC_BLOCK (i);
1993 /* Delete all unreachable basic blocks. */
1996 delete_unreachable_blocks ()
1998 basic_block *worklist, *tos;
1999 int deleted_handler;
2004 tos = worklist = (basic_block *) xmalloc (sizeof (basic_block) * n);
2006 /* Use basic_block->aux as a marker. Clear them all. */
2008 for (i = 0; i < n; ++i)
2009 BASIC_BLOCK (i)->aux = NULL;
2011 /* Add our starting points to the worklist. Almost always there will
2012 be only one. It isn't inconcievable that we might one day directly
2013 support Fortran alternate entry points. */
2015 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
2019 /* Mark the block with a handy non-null value. */
2023 /* Iterate: find everything reachable from what we've already seen. */
2025 while (tos != worklist)
2027 basic_block b = *--tos;
2029 for (e = b->succ; e; e = e->succ_next)
2037 /* Delete all unreachable basic blocks. Count down so that we don't
2038 interfere with the block renumbering that happens in flow_delete_block. */
2040 deleted_handler = 0;
2042 for (i = n - 1; i >= 0; --i)
2044 basic_block b = BASIC_BLOCK (i);
2047 /* This block was found. Tidy up the mark. */
2050 deleted_handler |= flow_delete_block (b);
2053 tidy_fallthru_edges ();
2055 /* If we deleted an exception handler, we may have EH region begin/end
2056 blocks to remove as well. */
2057 if (deleted_handler)
2058 delete_eh_regions ();
2063 /* Find EH regions for which there is no longer a handler, and delete them. */
2066 delete_eh_regions ()
2070 update_rethrow_references ();
2072 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
2073 if (GET_CODE (insn) == NOTE)
2075 if ((NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
2076 || (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
2078 int num = NOTE_EH_HANDLER (insn);
2079 /* A NULL handler indicates a region is no longer needed,
2080 as long as its rethrow label isn't used. */
2081 if (get_first_handler (num) == NULL && ! rethrow_used (num))
2083 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
2084 NOTE_SOURCE_FILE (insn) = 0;
2090 /* Return true if NOTE is not one of the ones that must be kept paired,
2091 so that we may simply delete them. */
2094 can_delete_note_p (note)
2097 return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED
2098 || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK);
2101 /* Unlink a chain of insns between START and FINISH, leaving notes
2102 that must be paired. */
2105 flow_delete_insn_chain (start, finish)
2108 /* Unchain the insns one by one. It would be quicker to delete all
2109 of these with a single unchaining, rather than one at a time, but
2110 we need to keep the NOTE's. */
2116 next = NEXT_INSN (start);
2117 if (GET_CODE (start) == NOTE && !can_delete_note_p (start))
2119 else if (GET_CODE (start) == CODE_LABEL
2120 && ! can_delete_label_p (start))
2122 const char *name = LABEL_NAME (start);
2123 PUT_CODE (start, NOTE);
2124 NOTE_LINE_NUMBER (start) = NOTE_INSN_DELETED_LABEL;
2125 NOTE_SOURCE_FILE (start) = name;
2128 next = flow_delete_insn (start);
2130 if (start == finish)
2136 /* Delete the insns in a (non-live) block. We physically delete every
2137 non-deleted-note insn, and update the flow graph appropriately.
2139 Return nonzero if we deleted an exception handler. */
2141 /* ??? Preserving all such notes strikes me as wrong. It would be nice
2142 to post-process the stream to remove empty blocks, loops, ranges, etc. */
2145 flow_delete_block (b)
2148 int deleted_handler = 0;
2151 /* If the head of this block is a CODE_LABEL, then it might be the
2152 label for an exception handler which can't be reached.
2154 We need to remove the label from the exception_handler_label list
2155 and remove the associated NOTE_INSN_EH_REGION_BEG and
2156 NOTE_INSN_EH_REGION_END notes. */
2160 never_reached_warning (insn);
2162 if (GET_CODE (insn) == CODE_LABEL)
2164 rtx x, *prev = &exception_handler_labels;
2166 for (x = exception_handler_labels; x; x = XEXP (x, 1))
2168 if (XEXP (x, 0) == insn)
2170 /* Found a match, splice this label out of the EH label list. */
2171 *prev = XEXP (x, 1);
2172 XEXP (x, 1) = NULL_RTX;
2173 XEXP (x, 0) = NULL_RTX;
2175 /* Remove the handler from all regions */
2176 remove_handler (insn);
2177 deleted_handler = 1;
2180 prev = &XEXP (x, 1);
2184 /* Include any jump table following the basic block. */
2186 if (GET_CODE (end) == JUMP_INSN
2187 && (tmp = JUMP_LABEL (end)) != NULL_RTX
2188 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
2189 && GET_CODE (tmp) == JUMP_INSN
2190 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
2191 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
2194 /* Include any barrier that may follow the basic block. */
2195 tmp = next_nonnote_insn (end);
2196 if (tmp && GET_CODE (tmp) == BARRIER)
2199 /* Selectively delete the entire chain. */
2200 flow_delete_insn_chain (insn, end);
2202 /* Remove the edges into and out of this block. Note that there may
2203 indeed be edges in, if we are removing an unreachable loop. */
2207 for (e = b->pred; e; e = next)
2209 for (q = &e->src->succ; *q != e; q = &(*q)->succ_next)
2212 next = e->pred_next;
2216 for (e = b->succ; e; e = next)
2218 for (q = &e->dest->pred; *q != e; q = &(*q)->pred_next)
2221 next = e->succ_next;
2230 /* Remove the basic block from the array, and compact behind it. */
2233 return deleted_handler;
2236 /* Remove block B from the basic block array and compact behind it. */
2242 int i, n = n_basic_blocks;
2244 for (i = b->index; i + 1 < n; ++i)
2246 basic_block x = BASIC_BLOCK (i + 1);
2247 BASIC_BLOCK (i) = x;
2251 basic_block_info->num_elements--;
2255 /* Delete INSN by patching it out. Return the next insn. */
2258 flow_delete_insn (insn)
2261 rtx prev = PREV_INSN (insn);
2262 rtx next = NEXT_INSN (insn);
2265 PREV_INSN (insn) = NULL_RTX;
2266 NEXT_INSN (insn) = NULL_RTX;
2267 INSN_DELETED_P (insn) = 1;
2270 NEXT_INSN (prev) = next;
2272 PREV_INSN (next) = prev;
2274 set_last_insn (prev);
2276 if (GET_CODE (insn) == CODE_LABEL)
2277 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2279 /* If deleting a jump, decrement the use count of the label. Deleting
2280 the label itself should happen in the normal course of block merging. */
2281 if (GET_CODE (insn) == JUMP_INSN
2282 && JUMP_LABEL (insn)
2283 && GET_CODE (JUMP_LABEL (insn)) == CODE_LABEL)
2284 LABEL_NUSES (JUMP_LABEL (insn))--;
2286 /* Also if deleting an insn that references a label. */
2287 else if ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX
2288 && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
2289 LABEL_NUSES (XEXP (note, 0))--;
2294 /* True if a given label can be deleted. */
2297 can_delete_label_p (label)
2302 if (LABEL_PRESERVE_P (label))
2305 for (x = forced_labels; x; x = XEXP (x, 1))
2306 if (label == XEXP (x, 0))
2308 for (x = label_value_list; x; x = XEXP (x, 1))
2309 if (label == XEXP (x, 0))
2311 for (x = exception_handler_labels; x; x = XEXP (x, 1))
2312 if (label == XEXP (x, 0))
2315 /* User declared labels must be preserved. */
2316 if (LABEL_NAME (label) != 0)
2323 tail_recursion_label_p (label)
2328 for (x = tail_recursion_label_list; x; x = XEXP (x, 1))
2329 if (label == XEXP (x, 0))
2335 /* Blocks A and B are to be merged into a single block A. The insns
2336 are already contiguous, hence `nomove'. */
2339 merge_blocks_nomove (a, b)
2343 rtx b_head, b_end, a_end;
2344 rtx del_first = NULL_RTX, del_last = NULL_RTX;
2347 /* If there was a CODE_LABEL beginning B, delete it. */
2350 if (GET_CODE (b_head) == CODE_LABEL)
2352 /* Detect basic blocks with nothing but a label. This can happen
2353 in particular at the end of a function. */
2354 if (b_head == b_end)
2356 del_first = del_last = b_head;
2357 b_head = NEXT_INSN (b_head);
2360 /* Delete the basic block note. */
2361 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
2363 if (b_head == b_end)
2368 b_head = NEXT_INSN (b_head);
2371 /* If there was a jump out of A, delete it. */
2373 if (GET_CODE (a_end) == JUMP_INSN)
2377 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
2378 if (GET_CODE (prev) != NOTE
2379 || NOTE_LINE_NUMBER (prev) == NOTE_INSN_BASIC_BLOCK
2386 /* If this was a conditional jump, we need to also delete
2387 the insn that set cc0. */
2388 if (prev && sets_cc0_p (prev))
2391 prev = prev_nonnote_insn (prev);
2400 else if (GET_CODE (NEXT_INSN (a_end)) == BARRIER)
2401 del_first = NEXT_INSN (a_end);
2403 /* Delete everything marked above as well as crap that might be
2404 hanging out between the two blocks. */
2405 flow_delete_insn_chain (del_first, del_last);
2407 /* Normally there should only be one successor of A and that is B, but
2408 partway though the merge of blocks for conditional_execution we'll
2409 be merging a TEST block with THEN and ELSE successors. Free the
2410 whole lot of them and hope the caller knows what they're doing. */
2412 remove_edge (a->succ);
2414 /* Adjust the edges out of B for the new owner. */
2415 for (e = b->succ; e; e = e->succ_next)
2419 /* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */
2420 b->pred = b->succ = NULL;
2422 /* Reassociate the insns of B with A. */
2425 if (basic_block_for_insn)
2427 BLOCK_FOR_INSN (b_head) = a;
2428 while (b_head != b_end)
2430 b_head = NEXT_INSN (b_head);
2431 BLOCK_FOR_INSN (b_head) = a;
2441 /* Blocks A and B are to be merged into a single block. A has no incoming
2442 fallthru edge, so it can be moved before B without adding or modifying
2443 any jumps (aside from the jump from A to B). */
2446 merge_blocks_move_predecessor_nojumps (a, b)
2449 rtx start, end, barrier;
2455 barrier = next_nonnote_insn (end);
2456 if (GET_CODE (barrier) != BARRIER)
2458 flow_delete_insn (barrier);
2460 /* Move block and loop notes out of the chain so that we do not
2461 disturb their order.
2463 ??? A better solution would be to squeeze out all the non-nested notes
2464 and adjust the block trees appropriately. Even better would be to have
2465 a tighter connection between block trees and rtl so that this is not
2467 start = squeeze_notes (start, end);
2469 /* Scramble the insn chain. */
2470 if (end != PREV_INSN (b->head))
2471 reorder_insns (start, end, PREV_INSN (b->head));
2475 fprintf (rtl_dump_file, "Moved block %d before %d and merged.\n",
2476 a->index, b->index);
2479 /* Swap the records for the two blocks around. Although we are deleting B,
2480 A is now where B was and we want to compact the BB array from where
2482 BASIC_BLOCK (a->index) = b;
2483 BASIC_BLOCK (b->index) = a;
2485 a->index = b->index;
2488 /* Now blocks A and B are contiguous. Merge them. */
2489 merge_blocks_nomove (a, b);
2494 /* Blocks A and B are to be merged into a single block. B has no outgoing
2495 fallthru edge, so it can be moved after A without adding or modifying
2496 any jumps (aside from the jump from A to B). */
2499 merge_blocks_move_successor_nojumps (a, b)
2502 rtx start, end, barrier;
2506 barrier = NEXT_INSN (end);
2508 /* Recognize a jump table following block B. */
2509 if (GET_CODE (barrier) == CODE_LABEL
2510 && NEXT_INSN (barrier)
2511 && GET_CODE (NEXT_INSN (barrier)) == JUMP_INSN
2512 && (GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_VEC
2513 || GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_DIFF_VEC))
2515 end = NEXT_INSN (barrier);
2516 barrier = NEXT_INSN (end);
2519 /* There had better have been a barrier there. Delete it. */
2520 if (GET_CODE (barrier) != BARRIER)
2522 flow_delete_insn (barrier);
2524 /* Move block and loop notes out of the chain so that we do not
2525 disturb their order.
2527 ??? A better solution would be to squeeze out all the non-nested notes
2528 and adjust the block trees appropriately. Even better would be to have
2529 a tighter connection between block trees and rtl so that this is not
2531 start = squeeze_notes (start, end);
2533 /* Scramble the insn chain. */
2534 reorder_insns (start, end, a->end);
2536 /* Now blocks A and B are contiguous. Merge them. */
2537 merge_blocks_nomove (a, b);
2541 fprintf (rtl_dump_file, "Moved block %d after %d and merged.\n",
2542 b->index, a->index);
2548 /* Attempt to merge basic blocks that are potentially non-adjacent.
2549 Return true iff the attempt succeeded. */
2552 merge_blocks (e, b, c)
2556 /* If C has a tail recursion label, do not merge. There is no
2557 edge recorded from the call_placeholder back to this label, as
2558 that would make optimize_sibling_and_tail_recursive_calls more
2559 complex for no gain. */
2560 if (GET_CODE (c->head) == CODE_LABEL
2561 && tail_recursion_label_p (c->head))
2564 /* If B has a fallthru edge to C, no need to move anything. */
2565 if (e->flags & EDGE_FALLTHRU)
2567 merge_blocks_nomove (b, c);
2571 fprintf (rtl_dump_file, "Merged %d and %d without moving.\n",
2572 b->index, c->index);
2581 int c_has_outgoing_fallthru;
2582 int b_has_incoming_fallthru;
2584 /* We must make sure to not munge nesting of exception regions,
2585 lexical blocks, and loop notes.
2587 The first is taken care of by requiring that the active eh
2588 region at the end of one block always matches the active eh
2589 region at the beginning of the next block.
2591 The later two are taken care of by squeezing out all the notes. */
2593 /* ??? A throw/catch edge (or any abnormal edge) should be rarely
2594 executed and we may want to treat blocks which have two out
2595 edges, one normal, one abnormal as only having one edge for
2596 block merging purposes. */
2598 for (tmp_edge = c->succ; tmp_edge; tmp_edge = tmp_edge->succ_next)
2599 if (tmp_edge->flags & EDGE_FALLTHRU)
2601 c_has_outgoing_fallthru = (tmp_edge != NULL);
2603 for (tmp_edge = b->pred; tmp_edge; tmp_edge = tmp_edge->pred_next)
2604 if (tmp_edge->flags & EDGE_FALLTHRU)
2606 b_has_incoming_fallthru = (tmp_edge != NULL);
2608 /* If B does not have an incoming fallthru, and the exception regions
2609 match, then it can be moved immediately before C without introducing
2612 C can not be the first block, so we do not have to worry about
2613 accessing a non-existent block. */
2614 d = BASIC_BLOCK (c->index - 1);
2615 if (! b_has_incoming_fallthru
2616 && d->eh_end == b->eh_beg
2617 && b->eh_end == c->eh_beg)
2618 return merge_blocks_move_predecessor_nojumps (b, c);
2620 /* Otherwise, we're going to try to move C after B. Make sure the
2621 exception regions match.
2623 If B is the last basic block, then we must not try to access the
2624 block structure for block B + 1. Luckily in that case we do not
2625 need to worry about matching exception regions. */
2626 d = (b->index + 1 < n_basic_blocks ? BASIC_BLOCK (b->index + 1) : NULL);
2627 if (b->eh_end == c->eh_beg
2628 && (d == NULL || c->eh_end == d->eh_beg))
2630 /* If C does not have an outgoing fallthru, then it can be moved
2631 immediately after B without introducing or modifying jumps. */
2632 if (! c_has_outgoing_fallthru)
2633 return merge_blocks_move_successor_nojumps (b, c);
2635 /* Otherwise, we'll need to insert an extra jump, and possibly
2636 a new block to contain it. */
2637 /* ??? Not implemented yet. */
2644 /* Top level driver for merge_blocks. */
2651 /* Attempt to merge blocks as made possible by edge removal. If a block
2652 has only one successor, and the successor has only one predecessor,
2653 they may be combined. */
2655 for (i = 0; i < n_basic_blocks;)
2657 basic_block c, b = BASIC_BLOCK (i);
2660 /* A loop because chains of blocks might be combineable. */
2661 while ((s = b->succ) != NULL
2662 && s->succ_next == NULL
2663 && (s->flags & EDGE_EH) == 0
2664 && (c = s->dest) != EXIT_BLOCK_PTR
2665 && c->pred->pred_next == NULL
2666 /* If the jump insn has side effects, we can't kill the edge. */
2667 && (GET_CODE (b->end) != JUMP_INSN
2668 || onlyjump_p (b->end))
2669 && merge_blocks (s, b, c))
2672 /* Don't get confused by the index shift caused by deleting blocks. */
2677 /* The given edge should potentially be a fallthru edge. If that is in
2678 fact true, delete the jump and barriers that are in the way. */
2681 tidy_fallthru_edge (e, b, c)
2687 /* ??? In a late-running flow pass, other folks may have deleted basic
2688 blocks by nopping out blocks, leaving multiple BARRIERs between here
2689 and the target label. They ought to be chastized and fixed.
2691 We can also wind up with a sequence of undeletable labels between
2692 one block and the next.
2694 So search through a sequence of barriers, labels, and notes for
2695 the head of block C and assert that we really do fall through. */
2697 if (next_real_insn (b->end) != next_real_insn (PREV_INSN (c->head)))
2700 /* Remove what will soon cease being the jump insn from the source block.
2701 If block B consisted only of this single jump, turn it into a deleted
2704 if (GET_CODE (q) == JUMP_INSN
2706 && (any_uncondjump_p (q)
2707 || (b->succ == e && e->succ_next == NULL)))
2710 /* If this was a conditional jump, we need to also delete
2711 the insn that set cc0. */
2712 if (any_condjump_p (q) && sets_cc0_p (PREV_INSN (q)))
2719 NOTE_LINE_NUMBER (q) = NOTE_INSN_DELETED;
2720 NOTE_SOURCE_FILE (q) = 0;
2728 /* Selectively unlink the sequence. */
2729 if (q != PREV_INSN (c->head))
2730 flow_delete_insn_chain (NEXT_INSN (q), PREV_INSN (c->head));
2732 e->flags |= EDGE_FALLTHRU;
2735 /* Fix up edges that now fall through, or rather should now fall through
2736 but previously required a jump around now deleted blocks. Simplify
2737 the search by only examining blocks numerically adjacent, since this
2738 is how find_basic_blocks created them. */
2741 tidy_fallthru_edges ()
2745 for (i = 1; i < n_basic_blocks; ++i)
2747 basic_block b = BASIC_BLOCK (i - 1);
2748 basic_block c = BASIC_BLOCK (i);
2751 /* We care about simple conditional or unconditional jumps with
2754 If we had a conditional branch to the next instruction when
2755 find_basic_blocks was called, then there will only be one
2756 out edge for the block which ended with the conditional
2757 branch (since we do not create duplicate edges).
2759 Furthermore, the edge will be marked as a fallthru because we
2760 merge the flags for the duplicate edges. So we do not want to
2761 check that the edge is not a FALLTHRU edge. */
2762 if ((s = b->succ) != NULL
2763 && s->succ_next == NULL
2765 /* If the jump insn has side effects, we can't tidy the edge. */
2766 && (GET_CODE (b->end) != JUMP_INSN
2767 || onlyjump_p (b->end)))
2768 tidy_fallthru_edge (s, b, c);
2772 /* Perform data flow analysis.
2773 F is the first insn of the function; FLAGS is a set of PROP_* flags
2774 to be used in accumulating flow info. */
2777 life_analysis (f, file, flags)
2782 #ifdef ELIMINABLE_REGS
2784 static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
2787 /* Record which registers will be eliminated. We use this in
2790 CLEAR_HARD_REG_SET (elim_reg_set);
2792 #ifdef ELIMINABLE_REGS
2793 for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
2794 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
2796 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
2800 flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC);
2802 /* The post-reload life analysis have (on a global basis) the same
2803 registers live as was computed by reload itself. elimination
2804 Otherwise offsets and such may be incorrect.
2806 Reload will make some registers as live even though they do not
2809 We don't want to create new auto-incs after reload, since they
2810 are unlikely to be useful and can cause problems with shared
2812 if (reload_completed)
2813 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
2815 /* We want alias analysis information for local dead store elimination. */
2816 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
2817 init_alias_analysis ();
2819 /* Always remove no-op moves. Do this before other processing so
2820 that we don't have to keep re-scanning them. */
2821 delete_noop_moves (f);
2823 /* Some targets can emit simpler epilogues if they know that sp was
2824 not ever modified during the function. After reload, of course,
2825 we've already emitted the epilogue so there's no sense searching. */
2826 if (! reload_completed)
2827 notice_stack_pointer_modification (f);
2829 /* Allocate and zero out data structures that will record the
2830 data from lifetime analysis. */
2831 allocate_reg_life_data ();
2832 allocate_bb_life_data ();
2834 /* Find the set of registers live on function exit. */
2835 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
2837 /* "Update" life info from zero. It'd be nice to begin the
2838 relaxation with just the exit and noreturn blocks, but that set
2839 is not immediately handy. */
2841 if (flags & PROP_REG_INFO)
2842 memset (regs_ever_live, 0, sizeof (regs_ever_live));
2843 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
2846 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
2847 end_alias_analysis ();
2850 dump_flow_info (file);
2852 free_basic_block_vars (1);
2855 /* A subroutine of verify_wide_reg, called through for_each_rtx.
2856 Search for REGNO. If found, abort if it is not wider than word_mode. */
2859 verify_wide_reg_1 (px, pregno)
2864 unsigned int regno = *(int *) pregno;
2866 if (GET_CODE (x) == REG && REGNO (x) == regno)
2868 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
2875 /* A subroutine of verify_local_live_at_start. Search through insns
2876 between HEAD and END looking for register REGNO. */
2879 verify_wide_reg (regno, head, end)
2886 && for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no))
2890 head = NEXT_INSN (head);
2893 /* We didn't find the register at all. Something's way screwy. */
2895 fprintf (rtl_dump_file, "Aborting in verify_wide_reg; reg %d\n", regno);
2896 print_rtl_and_abort ();
2899 /* A subroutine of update_life_info. Verify that there are no untoward
2900 changes in live_at_start during a local update. */
2903 verify_local_live_at_start (new_live_at_start, bb)
2904 regset new_live_at_start;
2907 if (reload_completed)
2909 /* After reload, there are no pseudos, nor subregs of multi-word
2910 registers. The regsets should exactly match. */
2911 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
2915 fprintf (rtl_dump_file,
2916 "live_at_start mismatch in bb %d, aborting\n",
2918 debug_bitmap_file (rtl_dump_file, bb->global_live_at_start);
2919 debug_bitmap_file (rtl_dump_file, new_live_at_start);
2921 print_rtl_and_abort ();
2928 /* Find the set of changed registers. */
2929 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
2931 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
2933 /* No registers should die. */
2934 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
2937 fprintf (rtl_dump_file,
2938 "Register %d died unexpectedly in block %d\n", i,
2940 print_rtl_and_abort ();
2943 /* Verify that the now-live register is wider than word_mode. */
2944 verify_wide_reg (i, bb->head, bb->end);
2949 /* Updates life information starting with the basic blocks set in BLOCKS.
2950 If BLOCKS is null, consider it to be the universal set.
2952 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
2953 we are only expecting local modifications to basic blocks. If we find
2954 extra registers live at the beginning of a block, then we either killed
2955 useful data, or we have a broken split that wants data not provided.
2956 If we find registers removed from live_at_start, that means we have
2957 a broken peephole that is killing a register it shouldn't.
2959 ??? This is not true in one situation -- when a pre-reload splitter
2960 generates subregs of a multi-word pseudo, current life analysis will
2961 lose the kill. So we _can_ have a pseudo go live. How irritating.
2963 Including PROP_REG_INFO does not properly refresh regs_ever_live
2964 unless the caller resets it to zero. */
2967 update_life_info (blocks, extent, prop_flags)
2969 enum update_life_extent extent;
2973 regset_head tmp_head;
2976 tmp = INITIALIZE_REG_SET (tmp_head);
2978 /* For a global update, we go through the relaxation process again. */
2979 if (extent != UPDATE_LIFE_LOCAL)
2981 calculate_global_regs_live (blocks, blocks,
2982 prop_flags & PROP_SCAN_DEAD_CODE);
2984 /* If asked, remove notes from the blocks we'll update. */
2985 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
2986 count_or_remove_death_notes (blocks, 1);
2991 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
2993 basic_block bb = BASIC_BLOCK (i);
2995 COPY_REG_SET (tmp, bb->global_live_at_end);
2996 propagate_block (bb, tmp, NULL, NULL, prop_flags);
2998 if (extent == UPDATE_LIFE_LOCAL)
2999 verify_local_live_at_start (tmp, bb);
3004 for (i = n_basic_blocks - 1; i >= 0; --i)
3006 basic_block bb = BASIC_BLOCK (i);
3008 COPY_REG_SET (tmp, bb->global_live_at_end);
3009 propagate_block (bb, tmp, NULL, NULL, prop_flags);
3011 if (extent == UPDATE_LIFE_LOCAL)
3012 verify_local_live_at_start (tmp, bb);
3018 if (prop_flags & PROP_REG_INFO)
3020 /* The only pseudos that are live at the beginning of the function
3021 are those that were not set anywhere in the function. local-alloc
3022 doesn't know how to handle these correctly, so mark them as not
3023 local to any one basic block. */
3024 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
3025 FIRST_PSEUDO_REGISTER, i,
3026 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
3028 /* We have a problem with any pseudoreg that lives across the setjmp.
3029 ANSI says that if a user variable does not change in value between
3030 the setjmp and the longjmp, then the longjmp preserves it. This
3031 includes longjmp from a place where the pseudo appears dead.
3032 (In principle, the value still exists if it is in scope.)
3033 If the pseudo goes in a hard reg, some other value may occupy
3034 that hard reg where this pseudo is dead, thus clobbering the pseudo.
3035 Conclusion: such a pseudo must not go in a hard reg. */
3036 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
3037 FIRST_PSEUDO_REGISTER, i,
3039 if (regno_reg_rtx[i] != 0)
3041 REG_LIVE_LENGTH (i) = -1;
3042 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
3048 /* Free the variables allocated by find_basic_blocks.
3050 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
3053 free_basic_block_vars (keep_head_end_p)
3054 int keep_head_end_p;
3056 if (basic_block_for_insn)
3058 VARRAY_FREE (basic_block_for_insn);
3059 basic_block_for_insn = NULL;
3062 if (! keep_head_end_p)
3065 VARRAY_FREE (basic_block_info);
3068 ENTRY_BLOCK_PTR->aux = NULL;
3069 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
3070 EXIT_BLOCK_PTR->aux = NULL;
3071 EXIT_BLOCK_PTR->global_live_at_start = NULL;
3075 /* Return nonzero if the destination of SET equals the source. */
3081 rtx src = SET_SRC (set);
3082 rtx dst = SET_DEST (set);
3084 if (GET_CODE (src) == SUBREG && GET_CODE (dst) == SUBREG)
3086 if (SUBREG_WORD (src) != SUBREG_WORD (dst))
3088 src = SUBREG_REG (src);
3089 dst = SUBREG_REG (dst);
3092 return (GET_CODE (src) == REG && GET_CODE (dst) == REG
3093 && REGNO (src) == REGNO (dst));
3096 /* Return nonzero if an insn consists only of SETs, each of which only sets a
3103 rtx pat = PATTERN (insn);
3105 /* Insns carrying these notes are useful later on. */
3106 if (find_reg_note (insn, REG_EQUAL, NULL_RTX))
3109 if (GET_CODE (pat) == SET && set_noop_p (pat))
3112 if (GET_CODE (pat) == PARALLEL)
3115 /* If nothing but SETs of registers to themselves,
3116 this insn can also be deleted. */
3117 for (i = 0; i < XVECLEN (pat, 0); i++)
3119 rtx tem = XVECEXP (pat, 0, i);
3121 if (GET_CODE (tem) == USE
3122 || GET_CODE (tem) == CLOBBER)
3125 if (GET_CODE (tem) != SET || ! set_noop_p (tem))
3134 /* Delete any insns that copy a register to itself. */
3137 delete_noop_moves (f)
3141 for (insn = f; insn; insn = NEXT_INSN (insn))
3143 if (GET_CODE (insn) == INSN && noop_move_p (insn))
3145 PUT_CODE (insn, NOTE);
3146 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
3147 NOTE_SOURCE_FILE (insn) = 0;
3152 /* Determine if the stack pointer is constant over the life of the function.
3153 Only useful before prologues have been emitted. */
3156 notice_stack_pointer_modification_1 (x, pat, data)
3158 rtx pat ATTRIBUTE_UNUSED;
3159 void *data ATTRIBUTE_UNUSED;
3161 if (x == stack_pointer_rtx
3162 /* The stack pointer is only modified indirectly as the result
3163 of a push until later in flow. See the comments in rtl.texi
3164 regarding Embedded Side-Effects on Addresses. */
3165 || (GET_CODE (x) == MEM
3166 && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
3167 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
3168 current_function_sp_is_unchanging = 0;
3172 notice_stack_pointer_modification (f)
3177 /* Assume that the stack pointer is unchanging if alloca hasn't
3179 current_function_sp_is_unchanging = !current_function_calls_alloca;
3180 if (! current_function_sp_is_unchanging)
3183 for (insn = f; insn; insn = NEXT_INSN (insn))
3187 /* Check if insn modifies the stack pointer. */
3188 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
3190 if (! current_function_sp_is_unchanging)
3196 /* Mark a register in SET. Hard registers in large modes get all
3197 of their component registers set as well. */
3200 mark_reg (reg, xset)
3204 regset set = (regset) xset;
3205 int regno = REGNO (reg);
3207 if (GET_MODE (reg) == BLKmode)
3210 SET_REGNO_REG_SET (set, regno);
3211 if (regno < FIRST_PSEUDO_REGISTER)
3213 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
3215 SET_REGNO_REG_SET (set, regno + n);
3219 /* Mark those regs which are needed at the end of the function as live
3220 at the end of the last basic block. */
3223 mark_regs_live_at_end (set)
3228 /* If exiting needs the right stack value, consider the stack pointer
3229 live at the end of the function. */
3230 if ((HAVE_epilogue && reload_completed)
3231 || ! EXIT_IGNORE_STACK
3232 || (! FRAME_POINTER_REQUIRED
3233 && ! current_function_calls_alloca
3234 && flag_omit_frame_pointer)
3235 || current_function_sp_is_unchanging)
3237 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
3240 /* Mark the frame pointer if needed at the end of the function. If
3241 we end up eliminating it, it will be removed from the live list
3242 of each basic block by reload. */
3244 if (! reload_completed || frame_pointer_needed)
3246 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
3247 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3248 /* If they are different, also mark the hard frame pointer as live. */
3249 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
3250 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
3254 #ifdef PIC_OFFSET_TABLE_REGNUM
3255 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
3256 /* Many architectures have a GP register even without flag_pic.
3257 Assume the pic register is not in use, or will be handled by
3258 other means, if it is not fixed. */
3259 if (fixed_regs[PIC_OFFSET_TABLE_REGNUM])
3260 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
3264 /* Mark all global registers, and all registers used by the epilogue
3265 as being live at the end of the function since they may be
3266 referenced by our caller. */
3267 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3268 if (global_regs[i] || EPILOGUE_USES (i))
3269 SET_REGNO_REG_SET (set, i);
3271 /* Mark all call-saved registers that we actaully used. */
3272 if (HAVE_epilogue && reload_completed)
3274 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3275 if (regs_ever_live[i] && ! call_used_regs[i] && ! LOCAL_REGNO (i))
3276 SET_REGNO_REG_SET (set, i);
3279 /* Mark function return value. */
3280 diddle_return_value (mark_reg, set);
3283 /* Callback function for for_each_successor_phi. DATA is a regset.
3284 Sets the SRC_REGNO, the regno of the phi alternative for phi node
3285 INSN, in the regset. */
3288 set_phi_alternative_reg (insn, dest_regno, src_regno, data)
3289 rtx insn ATTRIBUTE_UNUSED;
3290 int dest_regno ATTRIBUTE_UNUSED;
3294 regset live = (regset) data;
3295 SET_REGNO_REG_SET (live, src_regno);
3299 /* Propagate global life info around the graph of basic blocks. Begin
3300 considering blocks with their corresponding bit set in BLOCKS_IN.
3301 If BLOCKS_IN is null, consider it the universal set.
3303 BLOCKS_OUT is set for every block that was changed. */
3306 calculate_global_regs_live (blocks_in, blocks_out, flags)
3307 sbitmap blocks_in, blocks_out;
3310 basic_block *queue, *qhead, *qtail, *qend;
3311 regset tmp, new_live_at_end;
3312 regset_head tmp_head;
3313 regset_head new_live_at_end_head;
3316 tmp = INITIALIZE_REG_SET (tmp_head);
3317 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
3319 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
3320 because the `head == tail' style test for an empty queue doesn't
3321 work with a full queue. */
3322 queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
3324 qhead = qend = queue + n_basic_blocks + 2;
3326 /* Queue the blocks set in the initial mask. Do this in reverse block
3327 number order so that we are more likely for the first round to do
3328 useful work. We use AUX non-null to flag that the block is queued. */
3331 /* Clear out the garbage that might be hanging out in bb->aux. */
3332 for (i = n_basic_blocks - 1; i >= 0; --i)
3333 BASIC_BLOCK (i)->aux = NULL;
3335 EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
3337 basic_block bb = BASIC_BLOCK (i);
3344 for (i = 0; i < n_basic_blocks; ++i)
3346 basic_block bb = BASIC_BLOCK (i);
3353 sbitmap_zero (blocks_out);
3355 while (qhead != qtail)
3357 int rescan, changed;
3366 /* Begin by propogating live_at_start from the successor blocks. */
3367 CLEAR_REG_SET (new_live_at_end);
3368 for (e = bb->succ; e; e = e->succ_next)
3370 basic_block sb = e->dest;
3371 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
3374 /* The all-important stack pointer must always be live. */
3375 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
3377 /* Before reload, there are a few registers that must be forced
3378 live everywhere -- which might not already be the case for
3379 blocks within infinite loops. */
3380 if (! reload_completed)
3382 /* Any reference to any pseudo before reload is a potential
3383 reference of the frame pointer. */
3384 SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
3386 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3387 /* Pseudos with argument area equivalences may require
3388 reloading via the argument pointer. */
3389 if (fixed_regs[ARG_POINTER_REGNUM])
3390 SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
3393 #ifdef PIC_OFFSET_TABLE_REGNUM
3394 /* Any constant, or pseudo with constant equivalences, may
3395 require reloading from memory using the pic register. */
3396 if (fixed_regs[PIC_OFFSET_TABLE_REGNUM])
3397 SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
3401 /* Regs used in phi nodes are not included in
3402 global_live_at_start, since they are live only along a
3403 particular edge. Set those regs that are live because of a
3404 phi node alternative corresponding to this particular block. */
3406 for_each_successor_phi (bb, &set_phi_alternative_reg,
3409 if (bb == ENTRY_BLOCK_PTR)
3411 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3415 /* On our first pass through this block, we'll go ahead and continue.
3416 Recognize first pass by local_set NULL. On subsequent passes, we
3417 get to skip out early if live_at_end wouldn't have changed. */
3419 if (bb->local_set == NULL)
3421 bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3422 bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3427 /* If any bits were removed from live_at_end, we'll have to
3428 rescan the block. This wouldn't be necessary if we had
3429 precalculated local_live, however with PROP_SCAN_DEAD_CODE
3430 local_live is really dependent on live_at_end. */
3431 CLEAR_REG_SET (tmp);
3432 rescan = bitmap_operation (tmp, bb->global_live_at_end,
3433 new_live_at_end, BITMAP_AND_COMPL);
3437 /* If any of the registers in the new live_at_end set are
3438 conditionally set in this basic block, we must rescan.
3439 This is because conditional lifetimes at the end of the
3440 block do not just take the live_at_end set into account,
3441 but also the liveness at the start of each successor
3442 block. We can miss changes in those sets if we only
3443 compare the new live_at_end against the previous one. */
3444 CLEAR_REG_SET (tmp);
3445 rescan = bitmap_operation (tmp, new_live_at_end,
3446 bb->cond_local_set, BITMAP_AND);
3451 /* Find the set of changed bits. Take this opportunity
3452 to notice that this set is empty and early out. */
3453 CLEAR_REG_SET (tmp);
3454 changed = bitmap_operation (tmp, bb->global_live_at_end,
3455 new_live_at_end, BITMAP_XOR);
3459 /* If any of the changed bits overlap with local_set,
3460 we'll have to rescan the block. Detect overlap by
3461 the AND with ~local_set turning off bits. */
3462 rescan = bitmap_operation (tmp, tmp, bb->local_set,
3467 /* Let our caller know that BB changed enough to require its
3468 death notes updated. */
3470 SET_BIT (blocks_out, bb->index);
3474 /* Add to live_at_start the set of all registers in
3475 new_live_at_end that aren't in the old live_at_end. */
3477 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
3479 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3481 changed = bitmap_operation (bb->global_live_at_start,
3482 bb->global_live_at_start,
3489 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3491 /* Rescan the block insn by insn to turn (a copy of) live_at_end
3492 into live_at_start. */
3493 propagate_block (bb, new_live_at_end, bb->local_set,
3494 bb->cond_local_set, flags);
3496 /* If live_at start didn't change, no need to go farther. */
3497 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
3500 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
3503 /* Queue all predecessors of BB so that we may re-examine
3504 their live_at_end. */
3505 for (e = bb->pred; e; e = e->pred_next)
3507 basic_block pb = e->src;
3508 if (pb->aux == NULL)
3519 FREE_REG_SET (new_live_at_end);
3523 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
3525 basic_block bb = BASIC_BLOCK (i);
3526 FREE_REG_SET (bb->local_set);
3527 FREE_REG_SET (bb->cond_local_set);
3532 for (i = n_basic_blocks - 1; i >= 0; --i)
3534 basic_block bb = BASIC_BLOCK (i);
3535 FREE_REG_SET (bb->local_set);
3536 FREE_REG_SET (bb->cond_local_set);
3543 /* Subroutines of life analysis. */
3545 /* Allocate the permanent data structures that represent the results
3546 of life analysis. Not static since used also for stupid life analysis. */
3549 allocate_bb_life_data ()
3553 for (i = 0; i < n_basic_blocks; i++)
3555 basic_block bb = BASIC_BLOCK (i);
3557 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3558 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3561 ENTRY_BLOCK_PTR->global_live_at_end
3562 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3563 EXIT_BLOCK_PTR->global_live_at_start
3564 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3566 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3570 allocate_reg_life_data ()
3574 max_regno = max_reg_num ();
3576 /* Recalculate the register space, in case it has grown. Old style
3577 vector oriented regsets would set regset_{size,bytes} here also. */
3578 allocate_reg_info (max_regno, FALSE, FALSE);
3580 /* Reset all the data we'll collect in propagate_block and its
3582 for (i = 0; i < max_regno; i++)
3586 REG_N_DEATHS (i) = 0;
3587 REG_N_CALLS_CROSSED (i) = 0;
3588 REG_LIVE_LENGTH (i) = 0;
3589 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
3593 /* Delete dead instructions for propagate_block. */
3596 propagate_block_delete_insn (bb, insn)
3600 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
3602 /* If the insn referred to a label, and that label was attached to
3603 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
3604 pretty much mandatory to delete it, because the ADDR_VEC may be
3605 referencing labels that no longer exist. */
3609 rtx label = XEXP (inote, 0);
3612 if (LABEL_NUSES (label) == 1
3613 && (next = next_nonnote_insn (label)) != NULL
3614 && GET_CODE (next) == JUMP_INSN
3615 && (GET_CODE (PATTERN (next)) == ADDR_VEC
3616 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
3618 rtx pat = PATTERN (next);
3619 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
3620 int len = XVECLEN (pat, diff_vec_p);
3623 for (i = 0; i < len; i++)
3624 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
3626 flow_delete_insn (next);
3630 if (bb->end == insn)
3631 bb->end = PREV_INSN (insn);
3632 flow_delete_insn (insn);
3635 /* Delete dead libcalls for propagate_block. Return the insn
3636 before the libcall. */
3639 propagate_block_delete_libcall (bb, insn, note)
3643 rtx first = XEXP (note, 0);
3644 rtx before = PREV_INSN (first);
3646 if (insn == bb->end)
3649 flow_delete_insn_chain (first, insn);
3653 /* Update the life-status of regs for one insn. Return the previous insn. */
3656 propagate_one_insn (pbi, insn)
3657 struct propagate_block_info *pbi;
3660 rtx prev = PREV_INSN (insn);
3661 int flags = pbi->flags;
3662 int insn_is_dead = 0;
3663 int libcall_is_dead = 0;
3667 if (! INSN_P (insn))
3670 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
3671 if (flags & PROP_SCAN_DEAD_CODE)
3673 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0,
3675 libcall_is_dead = (insn_is_dead && note != 0
3676 && libcall_dead_p (pbi, note, insn));
3679 /* We almost certainly don't want to delete prologue or epilogue
3680 instructions. Warn about probable compiler losage. */
3683 && (((HAVE_epilogue || HAVE_prologue)
3684 && prologue_epilogue_contains (insn))
3685 || (HAVE_sibcall_epilogue
3686 && sibcall_epilogue_contains (insn)))
3687 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
3689 if (flags & PROP_KILL_DEAD_CODE)
3691 warning ("ICE: would have deleted prologue/epilogue insn");
3692 if (!inhibit_warnings)
3695 libcall_is_dead = insn_is_dead = 0;
3698 /* If an instruction consists of just dead store(s) on final pass,
3700 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
3702 /* Record sets. Do this even for dead instructions, since they
3703 would have killed the values if they hadn't been deleted. */
3704 mark_set_regs (pbi, PATTERN (insn), insn);
3706 /* CC0 is now known to be dead. Either this insn used it,
3707 in which case it doesn't anymore, or clobbered it,
3708 so the next insn can't use it. */
3711 if (libcall_is_dead)
3713 prev = propagate_block_delete_libcall (pbi->bb, insn, note);
3714 insn = NEXT_INSN (prev);
3717 propagate_block_delete_insn (pbi->bb, insn);
3722 /* See if this is an increment or decrement that can be merged into
3723 a following memory address. */
3726 register rtx x = single_set (insn);
3728 /* Does this instruction increment or decrement a register? */
3729 if ((flags & PROP_AUTOINC)
3731 && GET_CODE (SET_DEST (x)) == REG
3732 && (GET_CODE (SET_SRC (x)) == PLUS
3733 || GET_CODE (SET_SRC (x)) == MINUS)
3734 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
3735 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
3736 /* Ok, look for a following memory ref we can combine with.
3737 If one is found, change the memory ref to a PRE_INC
3738 or PRE_DEC, cancel this insn, and return 1.
3739 Return 0 if nothing has been done. */
3740 && try_pre_increment_1 (pbi, insn))
3743 #endif /* AUTO_INC_DEC */
3745 CLEAR_REG_SET (pbi->new_set);
3747 /* If this is not the final pass, and this insn is copying the value of
3748 a library call and it's dead, don't scan the insns that perform the
3749 library call, so that the call's arguments are not marked live. */
3750 if (libcall_is_dead)
3752 /* Record the death of the dest reg. */
3753 mark_set_regs (pbi, PATTERN (insn), insn);
3755 insn = XEXP (note, 0);
3756 return PREV_INSN (insn);
3758 else if (GET_CODE (PATTERN (insn)) == SET
3759 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
3760 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
3761 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
3762 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
3763 /* We have an insn to pop a constant amount off the stack.
3764 (Such insns use PLUS regardless of the direction of the stack,
3765 and any insn to adjust the stack by a constant is always a pop.)
3766 These insns, if not dead stores, have no effect on life. */
3770 /* Any regs live at the time of a call instruction must not go
3771 in a register clobbered by calls. Find all regs now live and
3772 record this for them. */
3774 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
3775 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
3776 { REG_N_CALLS_CROSSED (i)++; });
3778 /* Record sets. Do this even for dead instructions, since they
3779 would have killed the values if they hadn't been deleted. */
3780 mark_set_regs (pbi, PATTERN (insn), insn);
3782 if (GET_CODE (insn) == CALL_INSN)
3788 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
3789 cond = COND_EXEC_TEST (PATTERN (insn));
3791 /* Non-constant calls clobber memory. */
3792 if (! CONST_CALL_P (insn))
3793 free_EXPR_LIST_list (&pbi->mem_set_list);
3795 /* There may be extra registers to be clobbered. */
3796 for (note = CALL_INSN_FUNCTION_USAGE (insn);
3798 note = XEXP (note, 1))
3799 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
3800 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
3801 cond, insn, pbi->flags);
3803 /* Calls change all call-used and global registers. */
3804 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3805 if (call_used_regs[i] && ! global_regs[i]
3808 /* We do not want REG_UNUSED notes for these registers. */
3809 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
3811 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
3815 /* If an insn doesn't use CC0, it becomes dead since we assume
3816 that every insn clobbers it. So show it dead here;
3817 mark_used_regs will set it live if it is referenced. */
3822 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
3824 /* Sometimes we may have inserted something before INSN (such as a move)
3825 when we make an auto-inc. So ensure we will scan those insns. */
3827 prev = PREV_INSN (insn);
3830 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
3836 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
3837 cond = COND_EXEC_TEST (PATTERN (insn));
3839 /* Calls use their arguments. */
3840 for (note = CALL_INSN_FUNCTION_USAGE (insn);
3842 note = XEXP (note, 1))
3843 if (GET_CODE (XEXP (note, 0)) == USE)
3844 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
3847 /* The stack ptr is used (honorarily) by a CALL insn. */
3848 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
3850 /* Calls may also reference any of the global registers,
3851 so they are made live. */
3852 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3854 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
3859 /* On final pass, update counts of how many insns in which each reg
3861 if (flags & PROP_REG_INFO)
3862 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
3863 { REG_LIVE_LENGTH (i)++; });
3868 /* Initialize a propagate_block_info struct for public consumption.
3869 Note that the structure itself is opaque to this file, but that
3870 the user can use the regsets provided here. */
3872 struct propagate_block_info *
3873 init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
3875 regset live, local_set, cond_local_set;
3878 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
3881 pbi->reg_live = live;
3882 pbi->mem_set_list = NULL_RTX;
3883 pbi->local_set = local_set;
3884 pbi->cond_local_set = cond_local_set;
3888 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
3889 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
3891 pbi->reg_next_use = NULL;
3893 pbi->new_set = BITMAP_XMALLOC ();
3895 #ifdef HAVE_conditional_execution
3896 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
3897 free_reg_cond_life_info);
3898 pbi->reg_cond_reg = BITMAP_XMALLOC ();
3900 /* If this block ends in a conditional branch, for each register live
3901 from one side of the branch and not the other, record the register
3902 as conditionally dead. */
3903 if (GET_CODE (bb->end) == JUMP_INSN
3904 && any_condjump_p (bb->end))
3906 regset_head diff_head;
3907 regset diff = INITIALIZE_REG_SET (diff_head);
3908 basic_block bb_true, bb_false;
3909 rtx cond_true, cond_false, set_src;
3912 /* Identify the successor blocks. */
3913 bb_true = bb->succ->dest;
3914 if (bb->succ->succ_next != NULL)
3916 bb_false = bb->succ->succ_next->dest;
3918 if (bb->succ->flags & EDGE_FALLTHRU)
3920 basic_block t = bb_false;
3924 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
3929 /* This can happen with a conditional jump to the next insn. */
3930 if (JUMP_LABEL (bb->end) != bb_true->head)
3933 /* Simplest way to do nothing. */
3937 /* Extract the condition from the branch. */
3938 set_src = SET_SRC (pc_set (bb->end));
3939 cond_true = XEXP (set_src, 0);
3940 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
3941 GET_MODE (cond_true), XEXP (cond_true, 0),
3942 XEXP (cond_true, 1));
3943 if (GET_CODE (XEXP (set_src, 1)) == PC)
3946 cond_false = cond_true;
3950 /* Compute which register lead different lives in the successors. */
3951 if (bitmap_operation (diff, bb_true->global_live_at_start,
3952 bb_false->global_live_at_start, BITMAP_XOR))
3954 rtx reg = XEXP (cond_true, 0);
3956 if (GET_CODE (reg) == SUBREG)
3957 reg = SUBREG_REG (reg);
3959 if (GET_CODE (reg) != REG)
3962 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
3964 /* For each such register, mark it conditionally dead. */
3965 EXECUTE_IF_SET_IN_REG_SET
3968 struct reg_cond_life_info *rcli;
3971 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
3973 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
3977 rcli->condition = cond;
3979 splay_tree_insert (pbi->reg_cond_dead, i,
3980 (splay_tree_value) rcli);
3984 FREE_REG_SET (diff);
3988 /* If this block has no successors, any stores to the frame that aren't
3989 used later in the block are dead. So make a pass over the block
3990 recording any such that are made and show them dead at the end. We do
3991 a very conservative and simple job here. */
3993 && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
3994 && (TYPE_RETURNS_STACK_DEPRESSED
3995 (TREE_TYPE (current_function_decl))))
3996 && (flags & PROP_SCAN_DEAD_CODE)
3997 && (bb->succ == NULL
3998 || (bb->succ->succ_next == NULL
3999 && bb->succ->dest == EXIT_BLOCK_PTR)))
4002 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
4003 if (GET_CODE (insn) == INSN
4004 && GET_CODE (PATTERN (insn)) == SET
4005 && GET_CODE (SET_DEST (PATTERN (insn))) == MEM)
4007 rtx mem = SET_DEST (PATTERN (insn));
4009 if (XEXP (mem, 0) == frame_pointer_rtx
4010 || (GET_CODE (XEXP (mem, 0)) == PLUS
4011 && XEXP (XEXP (mem, 0), 0) == frame_pointer_rtx
4012 && GET_CODE (XEXP (XEXP (mem, 0), 1)) == CONST_INT))
4015 /* Store a copy of mem, otherwise the address may be scrogged
4016 by find_auto_inc. This matters because insn_dead_p uses
4017 an rtx_equal_p check to determine if two addresses are
4018 the same. This works before find_auto_inc, but fails
4019 after find_auto_inc, causing discrepencies between the
4020 set of live registers calculated during the
4021 calculate_global_regs_live phase and what actually exists
4022 after flow completes, leading to aborts. */
4023 if (flags & PROP_AUTOINC)
4024 mem = shallow_copy_rtx (mem);
4026 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
4034 /* Release a propagate_block_info struct. */
4037 free_propagate_block_info (pbi)
4038 struct propagate_block_info *pbi;
4040 free_EXPR_LIST_list (&pbi->mem_set_list);
4042 BITMAP_XFREE (pbi->new_set);
4044 #ifdef HAVE_conditional_execution
4045 splay_tree_delete (pbi->reg_cond_dead);
4046 BITMAP_XFREE (pbi->reg_cond_reg);
4049 if (pbi->reg_next_use)
4050 free (pbi->reg_next_use);
4055 /* Compute the registers live at the beginning of a basic block BB from
4056 those live at the end.
4058 When called, REG_LIVE contains those live at the end. On return, it
4059 contains those live at the beginning.
4061 LOCAL_SET, if non-null, will be set with all registers killed
4062 unconditionally by this basic block.
4063 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
4064 killed conditionally by this basic block. If there is any unconditional
4065 set of a register, then the corresponding bit will be set in LOCAL_SET
4066 and cleared in COND_LOCAL_SET.
4067 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
4068 case, the resulting set will be equal to the union of the two sets that
4069 would otherwise be computed. */
4072 propagate_block (bb, live, local_set, cond_local_set, flags)
4076 regset cond_local_set;
4079 struct propagate_block_info *pbi;
4082 pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
4084 if (flags & PROP_REG_INFO)
4088 /* Process the regs live at the end of the block.
4089 Mark them as not local to any one basic block. */
4090 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
4091 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
4094 /* Scan the block an insn at a time from end to beginning. */
4096 for (insn = bb->end;; insn = prev)
4098 /* If this is a call to `setjmp' et al, warn if any
4099 non-volatile datum is live. */
4100 if ((flags & PROP_REG_INFO)
4101 && GET_CODE (insn) == NOTE
4102 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
4103 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
4105 prev = propagate_one_insn (pbi, insn);
4107 if (insn == bb->head)
4111 free_propagate_block_info (pbi);
4114 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
4115 (SET expressions whose destinations are registers dead after the insn).
4116 NEEDED is the regset that says which regs are alive after the insn.
4118 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
4120 If X is the entire body of an insn, NOTES contains the reg notes
4121 pertaining to the insn. */
4124 insn_dead_p (pbi, x, call_ok, notes)
4125 struct propagate_block_info *pbi;
4128 rtx notes ATTRIBUTE_UNUSED;
4130 enum rtx_code code = GET_CODE (x);
4133 /* If flow is invoked after reload, we must take existing AUTO_INC
4134 expresions into account. */
4135 if (reload_completed)
4137 for (; notes; notes = XEXP (notes, 1))
4139 if (REG_NOTE_KIND (notes) == REG_INC)
4141 int regno = REGNO (XEXP (notes, 0));
4143 /* Don't delete insns to set global regs. */
4144 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
4145 || REGNO_REG_SET_P (pbi->reg_live, regno))
4152 /* If setting something that's a reg or part of one,
4153 see if that register's altered value will be live. */
4157 rtx r = SET_DEST (x);
4160 if (GET_CODE (r) == CC0)
4161 return ! pbi->cc0_live;
4164 /* A SET that is a subroutine call cannot be dead. */
4165 if (GET_CODE (SET_SRC (x)) == CALL)
4171 /* Don't eliminate loads from volatile memory or volatile asms. */
4172 else if (volatile_refs_p (SET_SRC (x)))
4175 if (GET_CODE (r) == MEM)
4179 if (MEM_VOLATILE_P (r))
4182 /* Walk the set of memory locations we are currently tracking
4183 and see if one is an identical match to this memory location.
4184 If so, this memory write is dead (remember, we're walking
4185 backwards from the end of the block to the start). */
4186 temp = pbi->mem_set_list;
4189 rtx mem = XEXP (temp, 0);
4191 if (rtx_equal_p (mem, r))
4194 /* Check if memory reference matches an auto increment. Only
4195 post increment/decrement or modify are valid. */
4196 if (GET_MODE (mem) == GET_MODE (r)
4197 && (GET_CODE (XEXP (mem, 0)) == POST_DEC
4198 || GET_CODE (XEXP (mem, 0)) == POST_INC
4199 || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
4200 && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
4201 && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
4204 temp = XEXP (temp, 1);
4209 while (GET_CODE (r) == SUBREG
4210 || GET_CODE (r) == STRICT_LOW_PART
4211 || GET_CODE (r) == ZERO_EXTRACT)
4214 if (GET_CODE (r) == REG)
4216 int regno = REGNO (r);
4219 if (REGNO_REG_SET_P (pbi->reg_live, regno))
4222 /* If this is a hard register, verify that subsequent
4223 words are not needed. */
4224 if (regno < FIRST_PSEUDO_REGISTER)
4226 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
4229 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
4233 /* Don't delete insns to set global regs. */
4234 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
4237 /* Make sure insns to set the stack pointer aren't deleted. */
4238 if (regno == STACK_POINTER_REGNUM)
4241 /* ??? These bits might be redundant with the force live bits
4242 in calculate_global_regs_live. We would delete from
4243 sequential sets; whether this actually affects real code
4244 for anything but the stack pointer I don't know. */
4245 /* Make sure insns to set the frame pointer aren't deleted. */
4246 if (regno == FRAME_POINTER_REGNUM
4247 && (! reload_completed || frame_pointer_needed))
4249 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4250 if (regno == HARD_FRAME_POINTER_REGNUM
4251 && (! reload_completed || frame_pointer_needed))
4255 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4256 /* Make sure insns to set arg pointer are never deleted
4257 (if the arg pointer isn't fixed, there will be a USE
4258 for it, so we can treat it normally). */
4259 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
4263 /* Otherwise, the set is dead. */
4269 /* If performing several activities, insn is dead if each activity
4270 is individually dead. Also, CLOBBERs and USEs can be ignored; a
4271 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
4273 else if (code == PARALLEL)
4275 int i = XVECLEN (x, 0);
4277 for (i--; i >= 0; i--)
4278 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
4279 && GET_CODE (XVECEXP (x, 0, i)) != USE
4280 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
4286 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
4287 is not necessarily true for hard registers. */
4288 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
4289 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
4290 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
4293 /* We do not check other CLOBBER or USE here. An insn consisting of just
4294 a CLOBBER or just a USE should not be deleted. */
4298 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
4299 return 1 if the entire library call is dead.
4300 This is true if INSN copies a register (hard or pseudo)
4301 and if the hard return reg of the call insn is dead.
4302 (The caller should have tested the destination of the SET inside
4303 INSN already for death.)
4305 If this insn doesn't just copy a register, then we don't
4306 have an ordinary libcall. In that case, cse could not have
4307 managed to substitute the source for the dest later on,
4308 so we can assume the libcall is dead.
4310 PBI is the block info giving pseudoregs live before this insn.
4311 NOTE is the REG_RETVAL note of the insn. */
4314 libcall_dead_p (pbi, note, insn)
4315 struct propagate_block_info *pbi;
4319 rtx x = single_set (insn);
4323 register rtx r = SET_SRC (x);
4324 if (GET_CODE (r) == REG)
4326 rtx call = XEXP (note, 0);
4330 /* Find the call insn. */
4331 while (call != insn && GET_CODE (call) != CALL_INSN)
4332 call = NEXT_INSN (call);
4334 /* If there is none, do nothing special,
4335 since ordinary death handling can understand these insns. */
4339 /* See if the hard reg holding the value is dead.
4340 If this is a PARALLEL, find the call within it. */
4341 call_pat = PATTERN (call);
4342 if (GET_CODE (call_pat) == PARALLEL)
4344 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
4345 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
4346 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
4349 /* This may be a library call that is returning a value
4350 via invisible pointer. Do nothing special, since
4351 ordinary death handling can understand these insns. */
4355 call_pat = XVECEXP (call_pat, 0, i);
4358 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
4364 /* Return 1 if register REGNO was used before it was set, i.e. if it is
4365 live at function entry. Don't count global register variables, variables
4366 in registers that can be used for function arg passing, or variables in
4367 fixed hard registers. */
4370 regno_uninitialized (regno)
4373 if (n_basic_blocks == 0
4374 || (regno < FIRST_PSEUDO_REGISTER
4375 && (global_regs[regno]
4376 || fixed_regs[regno]
4377 || FUNCTION_ARG_REGNO_P (regno))))
4380 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
4383 /* 1 if register REGNO was alive at a place where `setjmp' was called
4384 and was set more than once or is an argument.
4385 Such regs may be clobbered by `longjmp'. */
4388 regno_clobbered_at_setjmp (regno)
4391 if (n_basic_blocks == 0)
4394 return ((REG_N_SETS (regno) > 1
4395 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
4396 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
4399 /* INSN references memory, possibly using autoincrement addressing modes.
4400 Find any entries on the mem_set_list that need to be invalidated due
4401 to an address change. */
4404 invalidate_mems_from_autoinc (pbi, insn)
4405 struct propagate_block_info *pbi;
4408 rtx note = REG_NOTES (insn);
4409 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
4411 if (REG_NOTE_KIND (note) == REG_INC)
4413 rtx temp = pbi->mem_set_list;
4414 rtx prev = NULL_RTX;
4419 next = XEXP (temp, 1);
4420 if (reg_overlap_mentioned_p (XEXP (note, 0), XEXP (temp, 0)))
4422 /* Splice temp out of list. */
4424 XEXP (prev, 1) = next;
4426 pbi->mem_set_list = next;
4427 free_EXPR_LIST_node (temp);
4437 /* EXP is either a MEM or a REG. Remove any dependant entries
4438 from pbi->mem_set_list. */
4441 invalidate_mems_from_set (pbi, exp)
4442 struct propagate_block_info *pbi;
4445 rtx temp = pbi->mem_set_list;
4446 rtx prev = NULL_RTX;
4451 next = XEXP (temp, 1);
4452 if ((GET_CODE (exp) == MEM
4453 && output_dependence (XEXP (temp, 0), exp))
4454 || (GET_CODE (exp) == REG
4455 && reg_overlap_mentioned_p (exp, XEXP (temp, 0))))
4457 /* Splice this entry out of the list. */
4459 XEXP (prev, 1) = next;
4461 pbi->mem_set_list = next;
4462 free_EXPR_LIST_node (temp);
4470 /* Process the registers that are set within X. Their bits are set to
4471 1 in the regset DEAD, because they are dead prior to this insn.
4473 If INSN is nonzero, it is the insn being processed.
4475 FLAGS is the set of operations to perform. */
4478 mark_set_regs (pbi, x, insn)
4479 struct propagate_block_info *pbi;
4482 rtx cond = NULL_RTX;
4487 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
4489 if (REG_NOTE_KIND (link) == REG_INC)
4490 mark_set_1 (pbi, SET, XEXP (link, 0),
4491 (GET_CODE (x) == COND_EXEC
4492 ? COND_EXEC_TEST (x) : NULL_RTX),
4496 switch (code = GET_CODE (x))
4500 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
4504 cond = COND_EXEC_TEST (x);
4505 x = COND_EXEC_CODE (x);
4511 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
4513 rtx sub = XVECEXP (x, 0, i);
4514 switch (code = GET_CODE (sub))
4517 if (cond != NULL_RTX)
4520 cond = COND_EXEC_TEST (sub);
4521 sub = COND_EXEC_CODE (sub);
4522 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
4528 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
4543 /* Process a single SET rtx, X. */
4546 mark_set_1 (pbi, code, reg, cond, insn, flags)
4547 struct propagate_block_info *pbi;
4549 rtx reg, cond, insn;
4552 int regno_first = -1, regno_last = -1;
4556 /* Some targets place small structures in registers for
4557 return values of functions. We have to detect this
4558 case specially here to get correct flow information. */
4559 if (GET_CODE (reg) == PARALLEL
4560 && GET_MODE (reg) == BLKmode)
4562 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
4563 mark_set_1 (pbi, code, XVECEXP (reg, 0, i), cond, insn, flags);
4567 /* Modifying just one hardware register of a multi-reg value or just a
4568 byte field of a register does not mean the value from before this insn
4569 is now dead. Of course, if it was dead after it's unused now. */
4571 switch (GET_CODE (reg))
4575 case STRICT_LOW_PART:
4576 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
4578 reg = XEXP (reg, 0);
4579 while (GET_CODE (reg) == SUBREG
4580 || GET_CODE (reg) == ZERO_EXTRACT
4581 || GET_CODE (reg) == SIGN_EXTRACT
4582 || GET_CODE (reg) == STRICT_LOW_PART);
4583 if (GET_CODE (reg) == MEM)
4585 not_dead = REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
4589 regno_last = regno_first = REGNO (reg);
4590 if (regno_first < FIRST_PSEUDO_REGISTER)
4591 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
4595 if (GET_CODE (SUBREG_REG (reg)) == REG)
4597 enum machine_mode outer_mode = GET_MODE (reg);
4598 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
4600 /* Identify the range of registers affected. This is moderately
4601 tricky for hard registers. See alter_subreg. */
4603 regno_last = regno_first = REGNO (SUBREG_REG (reg));
4604 if (regno_first < FIRST_PSEUDO_REGISTER)
4606 #ifdef ALTER_HARD_SUBREG
4607 regno_first = ALTER_HARD_SUBREG (outer_mode, SUBREG_WORD (reg),
4608 inner_mode, regno_first);
4610 regno_first += SUBREG_WORD (reg);
4612 regno_last = (regno_first
4613 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
4615 /* Since we've just adjusted the register number ranges, make
4616 sure REG matches. Otherwise some_was_live will be clear
4617 when it shouldn't have been, and we'll create incorrect
4618 REG_UNUSED notes. */
4619 reg = gen_rtx_REG (outer_mode, regno_first);
4623 /* If the number of words in the subreg is less than the number
4624 of words in the full register, we have a well-defined partial
4625 set. Otherwise the high bits are undefined.
4627 This is only really applicable to pseudos, since we just took
4628 care of multi-word hard registers. */
4629 if (((GET_MODE_SIZE (outer_mode)
4630 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
4631 < ((GET_MODE_SIZE (inner_mode)
4632 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
4633 not_dead = REGNO_REG_SET_P (pbi->reg_live, regno_first);
4635 reg = SUBREG_REG (reg);
4639 reg = SUBREG_REG (reg);
4646 /* If this set is a MEM, then it kills any aliased writes.
4647 If this set is a REG, then it kills any MEMs which use the reg. */
4648 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
4650 if (GET_CODE (reg) == MEM || GET_CODE (reg) == REG)
4651 invalidate_mems_from_set (pbi, reg);
4653 /* If the memory reference had embedded side effects (autoincrement
4654 address modes. Then we may need to kill some entries on the
4656 if (insn && GET_CODE (reg) == MEM)
4657 invalidate_mems_from_autoinc (pbi, insn);
4659 if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
4660 /* ??? With more effort we could track conditional memory life. */
4662 /* We do not know the size of a BLKmode store, so we do not track
4663 them for redundant store elimination. */
4664 && GET_MODE (reg) != BLKmode
4665 /* There are no REG_INC notes for SP, so we can't assume we'll see
4666 everything that invalidates it. To be safe, don't eliminate any
4667 stores though SP; none of them should be redundant anyway. */
4668 && ! reg_mentioned_p (stack_pointer_rtx, reg))
4671 /* Store a copy of mem, otherwise the address may be
4672 scrogged by find_auto_inc. */
4673 if (flags & PROP_AUTOINC)
4674 reg = shallow_copy_rtx (reg);
4676 pbi->mem_set_list = alloc_EXPR_LIST (0, reg, pbi->mem_set_list);
4680 if (GET_CODE (reg) == REG
4681 && ! (regno_first == FRAME_POINTER_REGNUM
4682 && (! reload_completed || frame_pointer_needed))
4683 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4684 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
4685 && (! reload_completed || frame_pointer_needed))
4687 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4688 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
4692 int some_was_live = 0, some_was_dead = 0;
4694 for (i = regno_first; i <= regno_last; ++i)
4696 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
4699 /* Order of the set operation matters here since both
4700 sets may be the same. */
4701 CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
4702 if (cond != NULL_RTX
4703 && ! REGNO_REG_SET_P (pbi->local_set, i))
4704 SET_REGNO_REG_SET (pbi->cond_local_set, i);
4706 SET_REGNO_REG_SET (pbi->local_set, i);
4708 if (code != CLOBBER)
4709 SET_REGNO_REG_SET (pbi->new_set, i);
4711 some_was_live |= needed_regno;
4712 some_was_dead |= ! needed_regno;
4715 #ifdef HAVE_conditional_execution
4716 /* Consider conditional death in deciding that the register needs
4718 if (some_was_live && ! not_dead
4719 /* The stack pointer is never dead. Well, not strictly true,
4720 but it's very difficult to tell from here. Hopefully
4721 combine_stack_adjustments will fix up the most egregious
4723 && regno_first != STACK_POINTER_REGNUM)
4725 for (i = regno_first; i <= regno_last; ++i)
4726 if (! mark_regno_cond_dead (pbi, i, cond))
4731 /* Additional data to record if this is the final pass. */
4732 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
4733 | PROP_DEATH_NOTES | PROP_AUTOINC))
4736 register int blocknum = pbi->bb->index;
4739 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4741 y = pbi->reg_next_use[regno_first];
4743 /* The next use is no longer next, since a store intervenes. */
4744 for (i = regno_first; i <= regno_last; ++i)
4745 pbi->reg_next_use[i] = 0;
4748 if (flags & PROP_REG_INFO)
4750 for (i = regno_first; i <= regno_last; ++i)
4752 /* Count (weighted) references, stores, etc. This counts a
4753 register twice if it is modified, but that is correct. */
4754 REG_N_SETS (i) += 1;
4755 REG_N_REFS (i) += (optimize_size ? 1
4756 : pbi->bb->loop_depth + 1);
4758 /* The insns where a reg is live are normally counted
4759 elsewhere, but we want the count to include the insn
4760 where the reg is set, and the normal counting mechanism
4761 would not count it. */
4762 REG_LIVE_LENGTH (i) += 1;
4765 /* If this is a hard reg, record this function uses the reg. */
4766 if (regno_first < FIRST_PSEUDO_REGISTER)
4768 for (i = regno_first; i <= regno_last; i++)
4769 regs_ever_live[i] = 1;
4773 /* Keep track of which basic blocks each reg appears in. */
4774 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
4775 REG_BASIC_BLOCK (regno_first) = blocknum;
4776 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
4777 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
4781 if (! some_was_dead)
4783 if (flags & PROP_LOG_LINKS)
4785 /* Make a logical link from the next following insn
4786 that uses this register, back to this insn.
4787 The following insns have already been processed.
4789 We don't build a LOG_LINK for hard registers containing
4790 in ASM_OPERANDs. If these registers get replaced,
4791 we might wind up changing the semantics of the insn,
4792 even if reload can make what appear to be valid
4793 assignments later. */
4794 if (y && (BLOCK_NUM (y) == blocknum)
4795 && (regno_first >= FIRST_PSEUDO_REGISTER
4796 || asm_noperands (PATTERN (y)) < 0))
4797 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
4802 else if (! some_was_live)
4804 if (flags & PROP_REG_INFO)
4805 REG_N_DEATHS (regno_first) += 1;
4807 if (flags & PROP_DEATH_NOTES)
4809 /* Note that dead stores have already been deleted
4810 when possible. If we get here, we have found a
4811 dead store that cannot be eliminated (because the
4812 same insn does something useful). Indicate this
4813 by marking the reg being set as dying here. */
4815 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
4820 if (flags & PROP_DEATH_NOTES)
4822 /* This is a case where we have a multi-word hard register
4823 and some, but not all, of the words of the register are
4824 needed in subsequent insns. Write REG_UNUSED notes
4825 for those parts that were not needed. This case should
4828 for (i = regno_first; i <= regno_last; ++i)
4829 if (! REGNO_REG_SET_P (pbi->reg_live, i))
4831 = alloc_EXPR_LIST (REG_UNUSED,
4832 gen_rtx_REG (reg_raw_mode[i], i),
4838 /* Mark the register as being dead. */
4841 /* The stack pointer is never dead. Well, not strictly true,
4842 but it's very difficult to tell from here. Hopefully
4843 combine_stack_adjustments will fix up the most egregious
4845 && regno_first != STACK_POINTER_REGNUM)
4847 for (i = regno_first; i <= regno_last; ++i)
4848 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
4851 else if (GET_CODE (reg) == REG)
4853 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4854 pbi->reg_next_use[regno_first] = 0;
4857 /* If this is the last pass and this is a SCRATCH, show it will be dying
4858 here and count it. */
4859 else if (GET_CODE (reg) == SCRATCH)
4861 if (flags & PROP_DEATH_NOTES)
4863 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
4867 #ifdef HAVE_conditional_execution
4868 /* Mark REGNO conditionally dead.
4869 Return true if the register is now unconditionally dead. */
4872 mark_regno_cond_dead (pbi, regno, cond)
4873 struct propagate_block_info *pbi;
4877 /* If this is a store to a predicate register, the value of the
4878 predicate is changing, we don't know that the predicate as seen
4879 before is the same as that seen after. Flush all dependent
4880 conditions from reg_cond_dead. This will make all such
4881 conditionally live registers unconditionally live. */
4882 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
4883 flush_reg_cond_reg (pbi, regno);
4885 /* If this is an unconditional store, remove any conditional
4886 life that may have existed. */
4887 if (cond == NULL_RTX)
4888 splay_tree_remove (pbi->reg_cond_dead, regno);
4891 splay_tree_node node;
4892 struct reg_cond_life_info *rcli;
4895 /* Otherwise this is a conditional set. Record that fact.
4896 It may have been conditionally used, or there may be a
4897 subsequent set with a complimentary condition. */
4899 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
4902 /* The register was unconditionally live previously.
4903 Record the current condition as the condition under
4904 which it is dead. */
4905 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
4906 rcli->condition = cond;
4907 splay_tree_insert (pbi->reg_cond_dead, regno,
4908 (splay_tree_value) rcli);
4910 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
4912 /* Not unconditionaly dead. */
4917 /* The register was conditionally live previously.
4918 Add the new condition to the old. */
4919 rcli = (struct reg_cond_life_info *) node->value;
4920 ncond = rcli->condition;
4921 ncond = ior_reg_cond (ncond, cond, 1);
4923 /* If the register is now unconditionally dead,
4924 remove the entry in the splay_tree. */
4925 if (ncond == const1_rtx)
4926 splay_tree_remove (pbi->reg_cond_dead, regno);
4929 rcli->condition = ncond;
4931 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
4933 /* Not unconditionaly dead. */
4942 /* Called from splay_tree_delete for pbi->reg_cond_life. */
4945 free_reg_cond_life_info (value)
4946 splay_tree_value value;
4948 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
4952 /* Helper function for flush_reg_cond_reg. */
4955 flush_reg_cond_reg_1 (node, data)
4956 splay_tree_node node;
4959 struct reg_cond_life_info *rcli;
4960 int *xdata = (int *) data;
4961 unsigned int regno = xdata[0];
4963 /* Don't need to search if last flushed value was farther on in
4964 the in-order traversal. */
4965 if (xdata[1] >= (int) node->key)
4968 /* Splice out portions of the expression that refer to regno. */
4969 rcli = (struct reg_cond_life_info *) node->value;
4970 rcli->condition = elim_reg_cond (rcli->condition, regno);
4972 /* If the entire condition is now false, signal the node to be removed. */
4973 if (rcli->condition == const0_rtx)
4975 xdata[1] = node->key;
4978 else if (rcli->condition == const1_rtx)
4984 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
4987 flush_reg_cond_reg (pbi, regno)
4988 struct propagate_block_info *pbi;
4995 while (splay_tree_foreach (pbi->reg_cond_dead,
4996 flush_reg_cond_reg_1, pair) == -1)
4997 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
4999 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
5002 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
5003 For ior/and, the ADD flag determines whether we want to add the new
5004 condition X to the old one unconditionally. If it is zero, we will
5005 only return a new expression if X allows us to simplify part of
5006 OLD, otherwise we return OLD unchanged to the caller.
5007 If ADD is nonzero, we will return a new condition in all cases. The
5008 toplevel caller of one of these functions should always pass 1 for
5012 ior_reg_cond (old, x, add)
5018 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
5020 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
5021 && GET_CODE (x) == reverse_condition (GET_CODE (old))
5022 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5024 if (GET_CODE (x) == GET_CODE (old)
5025 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5029 return gen_rtx_IOR (0, old, x);
5032 switch (GET_CODE (old))
5035 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
5036 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
5037 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5039 if (op0 == const0_rtx)
5041 if (op1 == const0_rtx)
5043 if (op0 == const1_rtx || op1 == const1_rtx)
5045 if (op0 == XEXP (old, 0))
5046 op0 = gen_rtx_IOR (0, op0, x);
5048 op1 = gen_rtx_IOR (0, op1, x);
5049 return gen_rtx_IOR (0, op0, op1);
5053 return gen_rtx_IOR (0, old, x);
5056 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
5057 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
5058 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5060 if (op0 == const1_rtx)
5062 if (op1 == const1_rtx)
5064 if (op0 == const0_rtx || op1 == const0_rtx)
5066 if (op0 == XEXP (old, 0))
5067 op0 = gen_rtx_IOR (0, op0, x);
5069 op1 = gen_rtx_IOR (0, op1, x);
5070 return gen_rtx_AND (0, op0, op1);
5074 return gen_rtx_IOR (0, old, x);
5077 op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
5078 if (op0 != XEXP (old, 0))
5079 return not_reg_cond (op0);
5082 return gen_rtx_IOR (0, old, x);
5093 enum rtx_code x_code;
5095 if (x == const0_rtx)
5097 else if (x == const1_rtx)
5099 x_code = GET_CODE (x);
5102 if (GET_RTX_CLASS (x_code) == '<'
5103 && GET_CODE (XEXP (x, 0)) == REG)
5105 if (XEXP (x, 1) != const0_rtx)
5108 return gen_rtx_fmt_ee (reverse_condition (x_code),
5109 VOIDmode, XEXP (x, 0), const0_rtx);
5111 return gen_rtx_NOT (0, x);
5115 and_reg_cond (old, x, add)
5121 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
5123 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
5124 && GET_CODE (x) == reverse_condition (GET_CODE (old))
5125 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5127 if (GET_CODE (x) == GET_CODE (old)
5128 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5132 return gen_rtx_AND (0, old, x);
5135 switch (GET_CODE (old))
5138 op0 = and_reg_cond (XEXP (old, 0), x, 0);
5139 op1 = and_reg_cond (XEXP (old, 1), x, 0);
5140 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5142 if (op0 == const0_rtx)
5144 if (op1 == const0_rtx)
5146 if (op0 == const1_rtx || op1 == const1_rtx)
5148 if (op0 == XEXP (old, 0))
5149 op0 = gen_rtx_AND (0, op0, x);
5151 op1 = gen_rtx_AND (0, op1, x);
5152 return gen_rtx_IOR (0, op0, op1);
5156 return gen_rtx_AND (0, old, x);
5159 op0 = and_reg_cond (XEXP (old, 0), x, 0);
5160 op1 = and_reg_cond (XEXP (old, 1), x, 0);
5161 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5163 if (op0 == const1_rtx)
5165 if (op1 == const1_rtx)
5167 if (op0 == const0_rtx || op1 == const0_rtx)
5169 if (op0 == XEXP (old, 0))
5170 op0 = gen_rtx_AND (0, op0, x);
5172 op1 = gen_rtx_AND (0, op1, x);
5173 return gen_rtx_AND (0, op0, op1);
5177 return gen_rtx_AND (0, old, x);
5180 op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
5181 if (op0 != XEXP (old, 0))
5182 return not_reg_cond (op0);
5185 return gen_rtx_AND (0, old, x);
5192 /* Given a condition X, remove references to reg REGNO and return the
5193 new condition. The removal will be done so that all conditions
5194 involving REGNO are considered to evaluate to false. This function
5195 is used when the value of REGNO changes. */
5198 elim_reg_cond (x, regno)
5204 if (GET_RTX_CLASS (GET_CODE (x)) == '<')
5206 if (REGNO (XEXP (x, 0)) == regno)
5211 switch (GET_CODE (x))
5214 op0 = elim_reg_cond (XEXP (x, 0), regno);
5215 op1 = elim_reg_cond (XEXP (x, 1), regno);
5216 if (op0 == const0_rtx || op1 == const0_rtx)
5218 if (op0 == const1_rtx)
5220 if (op1 == const1_rtx)
5222 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
5224 return gen_rtx_AND (0, op0, op1);
5227 op0 = elim_reg_cond (XEXP (x, 0), regno);
5228 op1 = elim_reg_cond (XEXP (x, 1), regno);
5229 if (op0 == const1_rtx || op1 == const1_rtx)
5231 if (op0 == const0_rtx)
5233 if (op1 == const0_rtx)
5235 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
5237 return gen_rtx_IOR (0, op0, op1);
5240 op0 = elim_reg_cond (XEXP (x, 0), regno);
5241 if (op0 == const0_rtx)
5243 if (op0 == const1_rtx)
5245 if (op0 != XEXP (x, 0))
5246 return not_reg_cond (op0);
5253 #endif /* HAVE_conditional_execution */
5257 /* Try to substitute the auto-inc expression INC as the address inside
5258 MEM which occurs in INSN. Currently, the address of MEM is an expression
5259 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
5260 that has a single set whose source is a PLUS of INCR_REG and something
5264 attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
5265 struct propagate_block_info *pbi;
5266 rtx inc, insn, mem, incr, incr_reg;
5268 int regno = REGNO (incr_reg);
5269 rtx set = single_set (incr);
5270 rtx q = SET_DEST (set);
5271 rtx y = SET_SRC (set);
5272 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
5274 /* Make sure this reg appears only once in this insn. */
5275 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
5278 if (dead_or_set_p (incr, incr_reg)
5279 /* Mustn't autoinc an eliminable register. */
5280 && (regno >= FIRST_PSEUDO_REGISTER
5281 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
5283 /* This is the simple case. Try to make the auto-inc. If
5284 we can't, we are done. Otherwise, we will do any
5285 needed updates below. */
5286 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
5289 else if (GET_CODE (q) == REG
5290 /* PREV_INSN used here to check the semi-open interval
5292 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
5293 /* We must also check for sets of q as q may be
5294 a call clobbered hard register and there may
5295 be a call between PREV_INSN (insn) and incr. */
5296 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
5298 /* We have *p followed sometime later by q = p+size.
5299 Both p and q must be live afterward,
5300 and q is not used between INSN and its assignment.
5301 Change it to q = p, ...*q..., q = q+size.
5302 Then fall into the usual case. */
5306 emit_move_insn (q, incr_reg);
5307 insns = get_insns ();
5310 if (basic_block_for_insn)
5311 for (temp = insns; temp; temp = NEXT_INSN (temp))
5312 set_block_for_insn (temp, pbi->bb);
5314 /* If we can't make the auto-inc, or can't make the
5315 replacement into Y, exit. There's no point in making
5316 the change below if we can't do the auto-inc and doing
5317 so is not correct in the pre-inc case. */
5320 validate_change (insn, &XEXP (mem, 0), inc, 1);
5321 validate_change (incr, &XEXP (y, opnum), q, 1);
5322 if (! apply_change_group ())
5325 /* We now know we'll be doing this change, so emit the
5326 new insn(s) and do the updates. */
5327 emit_insns_before (insns, insn);
5329 if (pbi->bb->head == insn)
5330 pbi->bb->head = insns;
5332 /* INCR will become a NOTE and INSN won't contain a
5333 use of INCR_REG. If a use of INCR_REG was just placed in
5334 the insn before INSN, make that the next use.
5335 Otherwise, invalidate it. */
5336 if (GET_CODE (PREV_INSN (insn)) == INSN
5337 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
5338 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
5339 pbi->reg_next_use[regno] = PREV_INSN (insn);
5341 pbi->reg_next_use[regno] = 0;
5346 /* REGNO is now used in INCR which is below INSN, but
5347 it previously wasn't live here. If we don't mark
5348 it as live, we'll put a REG_DEAD note for it
5349 on this insn, which is incorrect. */
5350 SET_REGNO_REG_SET (pbi->reg_live, regno);
5352 /* If there are any calls between INSN and INCR, show
5353 that REGNO now crosses them. */
5354 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
5355 if (GET_CODE (temp) == CALL_INSN)
5356 REG_N_CALLS_CROSSED (regno)++;
5361 /* If we haven't returned, it means we were able to make the
5362 auto-inc, so update the status. First, record that this insn
5363 has an implicit side effect. */
5365 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
5367 /* Modify the old increment-insn to simply copy
5368 the already-incremented value of our register. */
5369 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
5372 /* If that makes it a no-op (copying the register into itself) delete
5373 it so it won't appear to be a "use" and a "set" of this
5375 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
5377 /* If the original source was dead, it's dead now. */
5380 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
5382 remove_note (incr, note);
5383 if (XEXP (note, 0) != incr_reg)
5384 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
5387 PUT_CODE (incr, NOTE);
5388 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
5389 NOTE_SOURCE_FILE (incr) = 0;
5392 if (regno >= FIRST_PSEUDO_REGISTER)
5394 /* Count an extra reference to the reg. When a reg is
5395 incremented, spilling it is worse, so we want to make
5396 that less likely. */
5397 REG_N_REFS (regno) += (optimize_size ? 1 : pbi->bb->loop_depth + 1);
5399 /* Count the increment as a setting of the register,
5400 even though it isn't a SET in rtl. */
5401 REG_N_SETS (regno)++;
5405 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
5409 find_auto_inc (pbi, x, insn)
5410 struct propagate_block_info *pbi;
5414 rtx addr = XEXP (x, 0);
5415 HOST_WIDE_INT offset = 0;
5416 rtx set, y, incr, inc_val;
5418 int size = GET_MODE_SIZE (GET_MODE (x));
5420 if (GET_CODE (insn) == JUMP_INSN)
5423 /* Here we detect use of an index register which might be good for
5424 postincrement, postdecrement, preincrement, or predecrement. */
5426 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
5427 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
5429 if (GET_CODE (addr) != REG)
5432 regno = REGNO (addr);
5434 /* Is the next use an increment that might make auto-increment? */
5435 incr = pbi->reg_next_use[regno];
5436 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
5438 set = single_set (incr);
5439 if (set == 0 || GET_CODE (set) != SET)
5443 if (GET_CODE (y) != PLUS)
5446 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
5447 inc_val = XEXP (y, 1);
5448 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
5449 inc_val = XEXP (y, 0);
5453 if (GET_CODE (inc_val) == CONST_INT)
5455 if (HAVE_POST_INCREMENT
5456 && (INTVAL (inc_val) == size && offset == 0))
5457 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
5459 else if (HAVE_POST_DECREMENT
5460 && (INTVAL (inc_val) == -size && offset == 0))
5461 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
5463 else if (HAVE_PRE_INCREMENT
5464 && (INTVAL (inc_val) == size && offset == size))
5465 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
5467 else if (HAVE_PRE_DECREMENT
5468 && (INTVAL (inc_val) == -size && offset == -size))
5469 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
5471 else if (HAVE_POST_MODIFY_DISP && offset == 0)
5472 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
5473 gen_rtx_PLUS (Pmode,
5476 insn, x, incr, addr);
5478 else if (GET_CODE (inc_val) == REG
5479 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
5483 if (HAVE_POST_MODIFY_REG && offset == 0)
5484 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
5485 gen_rtx_PLUS (Pmode,
5488 insn, x, incr, addr);
5492 #endif /* AUTO_INC_DEC */
5495 mark_used_reg (pbi, reg, cond, insn)
5496 struct propagate_block_info *pbi;
5498 rtx cond ATTRIBUTE_UNUSED;
5501 int regno = REGNO (reg);
5502 int some_was_live = REGNO_REG_SET_P (pbi->reg_live, regno);
5503 int some_was_dead = ! some_was_live;
5507 /* A hard reg in a wide mode may really be multiple registers.
5508 If so, mark all of them just like the first. */
5509 if (regno < FIRST_PSEUDO_REGISTER)
5511 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5514 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, regno + n);
5515 some_was_live |= needed_regno;
5516 some_was_dead |= ! needed_regno;
5520 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
5522 /* Record where each reg is used, so when the reg is set we know
5523 the next insn that uses it. */
5524 pbi->reg_next_use[regno] = insn;
5527 if (pbi->flags & PROP_REG_INFO)
5529 if (regno < FIRST_PSEUDO_REGISTER)
5531 /* If this is a register we are going to try to eliminate,
5532 don't mark it live here. If we are successful in
5533 eliminating it, it need not be live unless it is used for
5534 pseudos, in which case it will have been set live when it
5535 was allocated to the pseudos. If the register will not
5536 be eliminated, reload will set it live at that point.
5538 Otherwise, record that this function uses this register. */
5539 /* ??? The PPC backend tries to "eliminate" on the pic
5540 register to itself. This should be fixed. In the mean
5541 time, hack around it. */
5543 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno)
5544 && (regno == FRAME_POINTER_REGNUM
5545 || regno == ARG_POINTER_REGNUM)))
5547 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5549 regs_ever_live[regno + --n] = 1;
5555 /* Keep track of which basic block each reg appears in. */
5557 register int blocknum = pbi->bb->index;
5558 if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN)
5559 REG_BASIC_BLOCK (regno) = blocknum;
5560 else if (REG_BASIC_BLOCK (regno) != blocknum)
5561 REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL;
5563 /* Count (weighted) number of uses of each reg. */
5564 REG_N_REFS (regno) += (optimize_size ? 1
5565 : pbi->bb->loop_depth + 1);
5569 /* Find out if any of the register was set this insn. */
5570 some_not_set = ! REGNO_REG_SET_P (pbi->new_set, regno);
5571 if (regno < FIRST_PSEUDO_REGISTER)
5573 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5575 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, regno + n);
5578 /* Record and count the insns in which a reg dies. If it is used in
5579 this insn and was dead below the insn then it dies in this insn.
5580 If it was set in this insn, we do not make a REG_DEAD note;
5581 likewise if we already made such a note. */
5582 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
5586 /* Check for the case where the register dying partially
5587 overlaps the register set by this insn. */
5588 if (regno < FIRST_PSEUDO_REGISTER
5589 && HARD_REGNO_NREGS (regno, GET_MODE (reg)) > 1)
5591 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5593 some_was_live |= REGNO_REG_SET_P (pbi->new_set, regno + n);
5596 /* If none of the words in X is needed, make a REG_DEAD note.
5597 Otherwise, we must make partial REG_DEAD notes. */
5598 if (! some_was_live)
5600 if ((pbi->flags & PROP_DEATH_NOTES)
5601 && ! find_regno_note (insn, REG_DEAD, regno))
5603 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
5605 if (pbi->flags & PROP_REG_INFO)
5606 REG_N_DEATHS (regno)++;
5610 /* Don't make a REG_DEAD note for a part of a register
5611 that is set in the insn. */
5613 n = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)) - 1;
5614 for (; n >= regno; n--)
5615 if (! REGNO_REG_SET_P (pbi->reg_live, n)
5616 && ! dead_or_set_regno_p (insn, n))
5618 = alloc_EXPR_LIST (REG_DEAD,
5619 gen_rtx_REG (reg_raw_mode[n], n),
5624 SET_REGNO_REG_SET (pbi->reg_live, regno);
5625 if (regno < FIRST_PSEUDO_REGISTER)
5627 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5629 SET_REGNO_REG_SET (pbi->reg_live, regno + n);
5632 #ifdef HAVE_conditional_execution
5633 /* If this is a conditional use, record that fact. If it is later
5634 conditionally set, we'll know to kill the register. */
5635 if (cond != NULL_RTX)
5637 splay_tree_node node;
5638 struct reg_cond_life_info *rcli;
5643 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
5646 /* The register was unconditionally live previously.
5647 No need to do anything. */
5651 /* The register was conditionally live previously.
5652 Subtract the new life cond from the old death cond. */
5653 rcli = (struct reg_cond_life_info *) node->value;
5654 ncond = rcli->condition;
5655 ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
5657 /* If the register is now unconditionally live, remove the
5658 entry in the splay_tree. */
5659 if (ncond == const0_rtx)
5661 rcli->condition = NULL_RTX;
5662 splay_tree_remove (pbi->reg_cond_dead, regno);
5666 rcli->condition = ncond;
5667 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5673 /* The register was not previously live at all. Record
5674 the condition under which it is still dead. */
5675 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
5676 rcli->condition = not_reg_cond (cond);
5677 splay_tree_insert (pbi->reg_cond_dead, regno,
5678 (splay_tree_value) rcli);
5680 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5683 else if (some_was_live)
5685 splay_tree_node node;
5686 struct reg_cond_life_info *rcli;
5688 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
5691 /* The register was conditionally live previously, but is now
5692 unconditionally so. Remove it from the conditionally dead
5693 list, so that a conditional set won't cause us to think
5695 rcli = (struct reg_cond_life_info *) node->value;
5696 rcli->condition = NULL_RTX;
5697 splay_tree_remove (pbi->reg_cond_dead, regno);
5704 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
5705 This is done assuming the registers needed from X are those that
5706 have 1-bits in PBI->REG_LIVE.
5708 INSN is the containing instruction. If INSN is dead, this function
5712 mark_used_regs (pbi, x, cond, insn)
5713 struct propagate_block_info *pbi;
5716 register RTX_CODE code;
5718 int flags = pbi->flags;
5721 code = GET_CODE (x);
5741 /* If we are clobbering a MEM, mark any registers inside the address
5743 if (GET_CODE (XEXP (x, 0)) == MEM)
5744 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
5748 /* Don't bother watching stores to mems if this is not the
5749 final pass. We'll not be deleting dead stores this round. */
5750 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
5752 /* Invalidate the data for the last MEM stored, but only if MEM is
5753 something that can be stored into. */
5754 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
5755 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
5756 /* Needn't clear the memory set list. */
5760 rtx temp = pbi->mem_set_list;
5761 rtx prev = NULL_RTX;
5766 next = XEXP (temp, 1);
5767 if (anti_dependence (XEXP (temp, 0), x))
5769 /* Splice temp out of the list. */
5771 XEXP (prev, 1) = next;
5773 pbi->mem_set_list = next;
5774 free_EXPR_LIST_node (temp);
5782 /* If the memory reference had embedded side effects (autoincrement
5783 address modes. Then we may need to kill some entries on the
5786 invalidate_mems_from_autoinc (pbi, insn);
5790 if (flags & PROP_AUTOINC)
5791 find_auto_inc (pbi, x, insn);
5796 #ifdef CLASS_CANNOT_CHANGE_MODE
5797 if (GET_CODE (SUBREG_REG (x)) == REG
5798 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
5799 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
5800 GET_MODE (SUBREG_REG (x))))
5801 REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
5804 /* While we're here, optimize this case. */
5806 if (GET_CODE (x) != REG)
5811 /* See a register other than being set => mark it as needed. */
5812 mark_used_reg (pbi, x, cond, insn);
5817 register rtx testreg = SET_DEST (x);
5820 /* If storing into MEM, don't show it as being used. But do
5821 show the address as being used. */
5822 if (GET_CODE (testreg) == MEM)
5825 if (flags & PROP_AUTOINC)
5826 find_auto_inc (pbi, testreg, insn);
5828 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
5829 mark_used_regs (pbi, SET_SRC (x), cond, insn);
5833 /* Storing in STRICT_LOW_PART is like storing in a reg
5834 in that this SET might be dead, so ignore it in TESTREG.
5835 but in some other ways it is like using the reg.
5837 Storing in a SUBREG or a bit field is like storing the entire
5838 register in that if the register's value is not used
5839 then this SET is not needed. */
5840 while (GET_CODE (testreg) == STRICT_LOW_PART
5841 || GET_CODE (testreg) == ZERO_EXTRACT
5842 || GET_CODE (testreg) == SIGN_EXTRACT
5843 || GET_CODE (testreg) == SUBREG)
5845 #ifdef CLASS_CANNOT_CHANGE_MODE
5846 if (GET_CODE (testreg) == SUBREG
5847 && GET_CODE (SUBREG_REG (testreg)) == REG
5848 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
5849 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
5850 GET_MODE (testreg)))
5851 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
5854 /* Modifying a single register in an alternate mode
5855 does not use any of the old value. But these other
5856 ways of storing in a register do use the old value. */
5857 if (GET_CODE (testreg) == SUBREG
5858 && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
5863 testreg = XEXP (testreg, 0);
5866 /* If this is a store into a register, recursively scan the
5867 value being stored. */
5869 if ((GET_CODE (testreg) == PARALLEL
5870 && GET_MODE (testreg) == BLKmode)
5871 || (GET_CODE (testreg) == REG
5872 && (regno = REGNO (testreg),
5873 ! (regno == FRAME_POINTER_REGNUM
5874 && (! reload_completed || frame_pointer_needed)))
5875 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
5876 && ! (regno == HARD_FRAME_POINTER_REGNUM
5877 && (! reload_completed || frame_pointer_needed))
5879 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
5880 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
5885 mark_used_regs (pbi, SET_DEST (x), cond, insn);
5886 mark_used_regs (pbi, SET_SRC (x), cond, insn);
5893 case UNSPEC_VOLATILE:
5897 /* Traditional and volatile asm instructions must be considered to use
5898 and clobber all hard registers, all pseudo-registers and all of
5899 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
5901 Consider for instance a volatile asm that changes the fpu rounding
5902 mode. An insn should not be moved across this even if it only uses
5903 pseudo-regs because it might give an incorrectly rounded result.
5905 ?!? Unfortunately, marking all hard registers as live causes massive
5906 problems for the register allocator and marking all pseudos as live
5907 creates mountains of uninitialized variable warnings.
5909 So for now, just clear the memory set list and mark any regs
5910 we can find in ASM_OPERANDS as used. */
5911 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
5912 free_EXPR_LIST_list (&pbi->mem_set_list);
5914 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
5915 We can not just fall through here since then we would be confused
5916 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
5917 traditional asms unlike their normal usage. */
5918 if (code == ASM_OPERANDS)
5922 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
5923 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
5929 if (cond != NULL_RTX)
5932 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
5934 cond = COND_EXEC_TEST (x);
5935 x = COND_EXEC_CODE (x);
5939 /* We _do_not_ want to scan operands of phi nodes. Operands of
5940 a phi function are evaluated only when control reaches this
5941 block along a particular edge. Therefore, regs that appear
5942 as arguments to phi should not be added to the global live at
5950 /* Recursively scan the operands of this expression. */
5953 register const char *fmt = GET_RTX_FORMAT (code);
5956 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5960 /* Tail recursive case: save a function call level. */
5966 mark_used_regs (pbi, XEXP (x, i), cond, insn);
5968 else if (fmt[i] == 'E')
5971 for (j = 0; j < XVECLEN (x, i); j++)
5972 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
5981 try_pre_increment_1 (pbi, insn)
5982 struct propagate_block_info *pbi;
5985 /* Find the next use of this reg. If in same basic block,
5986 make it do pre-increment or pre-decrement if appropriate. */
5987 rtx x = single_set (insn);
5988 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
5989 * INTVAL (XEXP (SET_SRC (x), 1)));
5990 int regno = REGNO (SET_DEST (x));
5991 rtx y = pbi->reg_next_use[regno];
5993 && SET_DEST (x) != stack_pointer_rtx
5994 && BLOCK_NUM (y) == BLOCK_NUM (insn)
5995 /* Don't do this if the reg dies, or gets set in y; a standard addressing
5996 mode would be better. */
5997 && ! dead_or_set_p (y, SET_DEST (x))
5998 && try_pre_increment (y, SET_DEST (x), amount))
6000 /* We have found a suitable auto-increment and already changed
6001 insn Y to do it. So flush this increment instruction. */
6002 propagate_block_delete_insn (pbi->bb, insn);
6004 /* Count a reference to this reg for the increment insn we are
6005 deleting. When a reg is incremented, spilling it is worse,
6006 so we want to make that less likely. */
6007 if (regno >= FIRST_PSEUDO_REGISTER)
6009 REG_N_REFS (regno) += (optimize_size ? 1
6010 : pbi->bb->loop_depth + 1);
6011 REG_N_SETS (regno)++;
6014 /* Flush any remembered memories depending on the value of
6015 the incremented register. */
6016 invalidate_mems_from_set (pbi, SET_DEST (x));
6023 /* Try to change INSN so that it does pre-increment or pre-decrement
6024 addressing on register REG in order to add AMOUNT to REG.
6025 AMOUNT is negative for pre-decrement.
6026 Returns 1 if the change could be made.
6027 This checks all about the validity of the result of modifying INSN. */
6030 try_pre_increment (insn, reg, amount)
6032 HOST_WIDE_INT amount;
6036 /* Nonzero if we can try to make a pre-increment or pre-decrement.
6037 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
6039 /* Nonzero if we can try to make a post-increment or post-decrement.
6040 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
6041 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
6042 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
6045 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
6048 /* From the sign of increment, see which possibilities are conceivable
6049 on this target machine. */
6050 if (HAVE_PRE_INCREMENT && amount > 0)
6052 if (HAVE_POST_INCREMENT && amount > 0)
6055 if (HAVE_PRE_DECREMENT && amount < 0)
6057 if (HAVE_POST_DECREMENT && amount < 0)
6060 if (! (pre_ok || post_ok))
6063 /* It is not safe to add a side effect to a jump insn
6064 because if the incremented register is spilled and must be reloaded
6065 there would be no way to store the incremented value back in memory. */
6067 if (GET_CODE (insn) == JUMP_INSN)
6072 use = find_use_as_address (PATTERN (insn), reg, 0);
6073 if (post_ok && (use == 0 || use == (rtx) 1))
6075 use = find_use_as_address (PATTERN (insn), reg, -amount);
6079 if (use == 0 || use == (rtx) 1)
6082 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
6085 /* See if this combination of instruction and addressing mode exists. */
6086 if (! validate_change (insn, &XEXP (use, 0),
6087 gen_rtx_fmt_e (amount > 0
6088 ? (do_post ? POST_INC : PRE_INC)
6089 : (do_post ? POST_DEC : PRE_DEC),
6093 /* Record that this insn now has an implicit side effect on X. */
6094 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
6098 #endif /* AUTO_INC_DEC */
6100 /* Find the place in the rtx X where REG is used as a memory address.
6101 Return the MEM rtx that so uses it.
6102 If PLUSCONST is nonzero, search instead for a memory address equivalent to
6103 (plus REG (const_int PLUSCONST)).
6105 If such an address does not appear, return 0.
6106 If REG appears more than once, or is used other than in such an address,
6110 find_use_as_address (x, reg, plusconst)
6113 HOST_WIDE_INT plusconst;
6115 enum rtx_code code = GET_CODE (x);
6116 const char *fmt = GET_RTX_FORMAT (code);
6118 register rtx value = 0;
6121 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
6124 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
6125 && XEXP (XEXP (x, 0), 0) == reg
6126 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
6127 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
6130 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
6132 /* If REG occurs inside a MEM used in a bit-field reference,
6133 that is unacceptable. */
6134 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
6135 return (rtx) (HOST_WIDE_INT) 1;
6139 return (rtx) (HOST_WIDE_INT) 1;
6141 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
6145 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
6149 return (rtx) (HOST_WIDE_INT) 1;
6151 else if (fmt[i] == 'E')
6154 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
6156 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
6160 return (rtx) (HOST_WIDE_INT) 1;
6168 /* Write information about registers and basic blocks into FILE.
6169 This is part of making a debugging dump. */
6172 dump_regset (r, outf)
6179 fputs (" (nil)", outf);
6183 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
6185 fprintf (outf, " %d", i);
6186 if (i < FIRST_PSEUDO_REGISTER)
6187 fprintf (outf, " [%s]",
6196 dump_regset (r, stderr);
6197 putc ('\n', stderr);
6201 dump_flow_info (file)
6205 static const char * const reg_class_names[] = REG_CLASS_NAMES;
6207 fprintf (file, "%d registers.\n", max_regno);
6208 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
6211 enum reg_class class, altclass;
6212 fprintf (file, "\nRegister %d used %d times across %d insns",
6213 i, REG_N_REFS (i), REG_LIVE_LENGTH (i));
6214 if (REG_BASIC_BLOCK (i) >= 0)
6215 fprintf (file, " in block %d", REG_BASIC_BLOCK (i));
6217 fprintf (file, "; set %d time%s", REG_N_SETS (i),
6218 (REG_N_SETS (i) == 1) ? "" : "s");
6219 if (REG_USERVAR_P (regno_reg_rtx[i]))
6220 fprintf (file, "; user var");
6221 if (REG_N_DEATHS (i) != 1)
6222 fprintf (file, "; dies in %d places", REG_N_DEATHS (i));
6223 if (REG_N_CALLS_CROSSED (i) == 1)
6224 fprintf (file, "; crosses 1 call");
6225 else if (REG_N_CALLS_CROSSED (i))
6226 fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i));
6227 if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
6228 fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
6229 class = reg_preferred_class (i);
6230 altclass = reg_alternate_class (i);
6231 if (class != GENERAL_REGS || altclass != ALL_REGS)
6233 if (altclass == ALL_REGS || class == ALL_REGS)
6234 fprintf (file, "; pref %s", reg_class_names[(int) class]);
6235 else if (altclass == NO_REGS)
6236 fprintf (file, "; %s or none", reg_class_names[(int) class]);
6238 fprintf (file, "; pref %s, else %s",
6239 reg_class_names[(int) class],
6240 reg_class_names[(int) altclass]);
6242 if (REG_POINTER (regno_reg_rtx[i]))
6243 fprintf (file, "; pointer");
6244 fprintf (file, ".\n");
6247 fprintf (file, "\n%d basic blocks, %d edges.\n", n_basic_blocks, n_edges);
6248 for (i = 0; i < n_basic_blocks; i++)
6250 register basic_block bb = BASIC_BLOCK (i);
6253 fprintf (file, "\nBasic block %d: first insn %d, last %d, loop_depth %d, count %d.\n",
6254 i, INSN_UID (bb->head), INSN_UID (bb->end), bb->loop_depth, bb->count);
6256 fprintf (file, "Predecessors: ");
6257 for (e = bb->pred; e; e = e->pred_next)
6258 dump_edge_info (file, e, 0);
6260 fprintf (file, "\nSuccessors: ");
6261 for (e = bb->succ; e; e = e->succ_next)
6262 dump_edge_info (file, e, 1);
6264 fprintf (file, "\nRegisters live at start:");
6265 dump_regset (bb->global_live_at_start, file);
6267 fprintf (file, "\nRegisters live at end:");
6268 dump_regset (bb->global_live_at_end, file);
6279 dump_flow_info (stderr);
6283 dump_edge_info (file, e, do_succ)
6288 basic_block side = (do_succ ? e->dest : e->src);
6290 if (side == ENTRY_BLOCK_PTR)
6291 fputs (" ENTRY", file);
6292 else if (side == EXIT_BLOCK_PTR)
6293 fputs (" EXIT", file);
6295 fprintf (file, " %d", side->index);
6298 fprintf (file, " count:%d", e->count);
6302 static const char * const bitnames[] = {
6303 "fallthru", "crit", "ab", "abcall", "eh", "fake"
6306 int i, flags = e->flags;
6310 for (i = 0; flags; i++)
6311 if (flags & (1 << i))
6317 if (i < (int) ARRAY_SIZE (bitnames))
6318 fputs (bitnames[i], file);
6320 fprintf (file, "%d", i);
6327 /* Print out one basic block with live information at start and end. */
6338 fprintf (outf, ";; Basic block %d, loop depth %d, count %d",
6339 bb->index, bb->loop_depth, bb->count);
6340 if (bb->eh_beg != -1 || bb->eh_end != -1)
6341 fprintf (outf, ", eh regions %d/%d", bb->eh_beg, bb->eh_end);
6344 fputs (";; Predecessors: ", outf);
6345 for (e = bb->pred; e; e = e->pred_next)
6346 dump_edge_info (outf, e, 0);
6349 fputs (";; Registers live at start:", outf);
6350 dump_regset (bb->global_live_at_start, outf);
6353 for (insn = bb->head, last = NEXT_INSN (bb->end);
6355 insn = NEXT_INSN (insn))
6356 print_rtl_single (outf, insn);
6358 fputs (";; Registers live at end:", outf);
6359 dump_regset (bb->global_live_at_end, outf);
6362 fputs (";; Successors: ", outf);
6363 for (e = bb->succ; e; e = e->succ_next)
6364 dump_edge_info (outf, e, 1);
6372 dump_bb (bb, stderr);
6379 dump_bb (BASIC_BLOCK (n), stderr);
6382 /* Like print_rtl, but also print out live information for the start of each
6386 print_rtl_with_bb (outf, rtx_first)
6390 register rtx tmp_rtx;
6393 fprintf (outf, "(nil)\n");
6397 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
6398 int max_uid = get_max_uid ();
6399 basic_block *start = (basic_block *)
6400 xcalloc (max_uid, sizeof (basic_block));
6401 basic_block *end = (basic_block *)
6402 xcalloc (max_uid, sizeof (basic_block));
6403 enum bb_state *in_bb_p = (enum bb_state *)
6404 xcalloc (max_uid, sizeof (enum bb_state));
6406 for (i = n_basic_blocks - 1; i >= 0; i--)
6408 basic_block bb = BASIC_BLOCK (i);
6411 start[INSN_UID (bb->head)] = bb;
6412 end[INSN_UID (bb->end)] = bb;
6413 for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x))
6415 enum bb_state state = IN_MULTIPLE_BB;
6416 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
6418 in_bb_p[INSN_UID (x)] = state;
6425 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
6430 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
6432 fprintf (outf, ";; Start of basic block %d, registers live:",
6434 dump_regset (bb->global_live_at_start, outf);
6438 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
6439 && GET_CODE (tmp_rtx) != NOTE
6440 && GET_CODE (tmp_rtx) != BARRIER)
6441 fprintf (outf, ";; Insn is not within a basic block\n");
6442 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
6443 fprintf (outf, ";; Insn is in multiple basic blocks\n");
6445 did_output = print_rtl_single (outf, tmp_rtx);
6447 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
6449 fprintf (outf, ";; End of basic block %d, registers live:\n",
6451 dump_regset (bb->global_live_at_end, outf);
6464 if (current_function_epilogue_delay_list != 0)
6466 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
6467 for (tmp_rtx = current_function_epilogue_delay_list; tmp_rtx != 0;
6468 tmp_rtx = XEXP (tmp_rtx, 1))
6469 print_rtl_single (outf, XEXP (tmp_rtx, 0));
6473 /* Dump the rtl into the current debugging dump file, then abort. */
6475 print_rtl_and_abort ()
6479 print_rtl_with_bb (rtl_dump_file, get_insns ());
6480 fclose (rtl_dump_file);
6485 /* Recompute register set/reference counts immediately prior to register
6488 This avoids problems with set/reference counts changing to/from values
6489 which have special meanings to the register allocators.
6491 Additionally, the reference counts are the primary component used by the
6492 register allocators to prioritize pseudos for allocation to hard regs.
6493 More accurate reference counts generally lead to better register allocation.
6495 F is the first insn to be scanned.
6497 LOOP_STEP denotes how much loop_depth should be incremented per
6498 loop nesting level in order to increase the ref count more for
6499 references in a loop.
6501 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
6502 possibly other information which is used by the register allocators. */
6505 recompute_reg_usage (f, loop_step)
6506 rtx f ATTRIBUTE_UNUSED;
6507 int loop_step ATTRIBUTE_UNUSED;
6509 allocate_reg_life_data ();
6510 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
6513 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
6514 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
6515 of the number of registers that died. */
6518 count_or_remove_death_notes (blocks, kill)
6524 for (i = n_basic_blocks - 1; i >= 0; --i)
6529 if (blocks && ! TEST_BIT (blocks, i))
6532 bb = BASIC_BLOCK (i);
6534 for (insn = bb->head;; insn = NEXT_INSN (insn))
6538 rtx *pprev = ®_NOTES (insn);
6543 switch (REG_NOTE_KIND (link))
6546 if (GET_CODE (XEXP (link, 0)) == REG)
6548 rtx reg = XEXP (link, 0);
6551 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
6554 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
6562 rtx next = XEXP (link, 1);
6563 free_EXPR_LIST_node (link);
6564 *pprev = link = next;
6570 pprev = &XEXP (link, 1);
6577 if (insn == bb->end)
6586 /* Update insns block within BB. */
6589 update_bb_for_insn (bb)
6594 if (! basic_block_for_insn)
6597 for (insn = bb->head; ; insn = NEXT_INSN (insn))
6599 set_block_for_insn (insn, bb);
6601 if (insn == bb->end)
6607 /* Record INSN's block as BB. */
6610 set_block_for_insn (insn, bb)
6614 size_t uid = INSN_UID (insn);
6615 if (uid >= basic_block_for_insn->num_elements)
6619 /* Add one-eighth the size so we don't keep calling xrealloc. */
6620 new_size = uid + (uid + 7) / 8;
6622 VARRAY_GROW (basic_block_for_insn, new_size);
6624 VARRAY_BB (basic_block_for_insn, uid) = bb;
6627 /* Record INSN's block number as BB. */
6628 /* ??? This has got to go. */
6631 set_block_num (insn, bb)
6635 set_block_for_insn (insn, BASIC_BLOCK (bb));
6638 /* Verify the CFG consistency. This function check some CFG invariants and
6639 aborts when something is wrong. Hope that this function will help to
6640 convert many optimization passes to preserve CFG consistent.
6642 Currently it does following checks:
6644 - test head/end pointers
6645 - overlapping of basic blocks
6646 - edge list corectness
6647 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
6648 - tails of basic blocks (ensure that boundary is necesary)
6649 - scans body of the basic block for JUMP_INSN, CODE_LABEL
6650 and NOTE_INSN_BASIC_BLOCK
6651 - check that all insns are in the basic blocks
6652 (except the switch handling code, barriers and notes)
6653 - check that all returns are followed by barriers
6655 In future it can be extended check a lot of other stuff as well
6656 (reachability of basic blocks, life information, etc. etc.). */
6661 const int max_uid = get_max_uid ();
6662 const rtx rtx_first = get_insns ();
6663 rtx last_head = get_last_insn ();
6664 basic_block *bb_info;
6666 int i, last_bb_num_seen, num_bb_notes, err = 0;
6668 bb_info = (basic_block *) xcalloc (max_uid, sizeof (basic_block));
6670 for (i = n_basic_blocks - 1; i >= 0; i--)
6672 basic_block bb = BASIC_BLOCK (i);
6673 rtx head = bb->head;
6676 /* Verify the end of the basic block is in the INSN chain. */
6677 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
6682 error ("End insn %d for block %d not found in the insn stream.",
6683 INSN_UID (end), bb->index);
6687 /* Work backwards from the end to the head of the basic block
6688 to verify the head is in the RTL chain. */
6689 for (; x != NULL_RTX; x = PREV_INSN (x))
6691 /* While walking over the insn chain, verify insns appear
6692 in only one basic block and initialize the BB_INFO array
6693 used by other passes. */
6694 if (bb_info[INSN_UID (x)] != NULL)
6696 error ("Insn %d is in multiple basic blocks (%d and %d)",
6697 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
6700 bb_info[INSN_UID (x)] = bb;
6707 error ("Head insn %d for block %d not found in the insn stream.",
6708 INSN_UID (head), bb->index);
6715 /* Now check the basic blocks (boundaries etc.) */
6716 for (i = n_basic_blocks - 1; i >= 0; i--)
6718 basic_block bb = BASIC_BLOCK (i);
6719 /* Check corectness of edge lists */
6728 "verify_flow_info: Basic block %d succ edge is corrupted\n",
6730 fprintf (stderr, "Predecessor: ");
6731 dump_edge_info (stderr, e, 0);
6732 fprintf (stderr, "\nSuccessor: ");
6733 dump_edge_info (stderr, e, 1);
6737 if (e->dest != EXIT_BLOCK_PTR)
6739 edge e2 = e->dest->pred;
6740 while (e2 && e2 != e)
6744 error ("Basic block %i edge lists are corrupted", bb->index);
6756 error ("Basic block %d pred edge is corrupted", bb->index);
6757 fputs ("Predecessor: ", stderr);
6758 dump_edge_info (stderr, e, 0);
6759 fputs ("\nSuccessor: ", stderr);
6760 dump_edge_info (stderr, e, 1);
6761 fputc ('\n', stderr);
6764 if (e->src != ENTRY_BLOCK_PTR)
6766 edge e2 = e->src->succ;
6767 while (e2 && e2 != e)
6771 error ("Basic block %i edge lists are corrupted", bb->index);
6778 /* OK pointers are correct. Now check the header of basic
6779 block. It ought to contain optional CODE_LABEL followed
6780 by NOTE_BASIC_BLOCK. */
6782 if (GET_CODE (x) == CODE_LABEL)
6786 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
6792 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
6794 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d\n",
6801 /* Do checks for empty blocks here */
6808 if (NOTE_INSN_BASIC_BLOCK_P (x))
6810 error ("NOTE_INSN_BASIC_BLOCK %d in the middle of basic block %d",
6811 INSN_UID (x), bb->index);
6818 if (GET_CODE (x) == JUMP_INSN
6819 || GET_CODE (x) == CODE_LABEL
6820 || GET_CODE (x) == BARRIER)
6822 error ("In basic block %d:", bb->index);
6823 fatal_insn ("Flow control insn inside a basic block", x);
6831 last_bb_num_seen = -1;
6836 if (NOTE_INSN_BASIC_BLOCK_P (x))
6838 basic_block bb = NOTE_BASIC_BLOCK (x);
6840 if (bb->index != last_bb_num_seen + 1)
6841 fatal ("Basic blocks not numbered consecutively");
6842 last_bb_num_seen = bb->index;
6845 if (!bb_info[INSN_UID (x)])
6847 switch (GET_CODE (x))
6854 /* An addr_vec is placed outside any block block. */
6856 && GET_CODE (NEXT_INSN (x)) == JUMP_INSN
6857 && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
6858 || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
6863 /* But in any case, non-deletable labels can appear anywhere. */
6867 fatal_insn ("Insn outside basic block", x);
6872 && GET_CODE (x) == JUMP_INSN
6873 && returnjump_p (x) && ! condjump_p (x)
6874 && ! (NEXT_INSN (x) && GET_CODE (NEXT_INSN (x)) == BARRIER))
6875 fatal_insn ("Return not followed by barrier", x);
6880 if (num_bb_notes != n_basic_blocks)
6881 fatal ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
6882 num_bb_notes, n_basic_blocks);
6891 /* Functions to access an edge list with a vector representation.
6892 Enough data is kept such that given an index number, the
6893 pred and succ that edge represents can be determined, or
6894 given a pred and a succ, its index number can be returned.
6895 This allows algorithms which consume a lot of memory to
6896 represent the normally full matrix of edge (pred,succ) with a
6897 single indexed vector, edge (EDGE_INDEX (pred, succ)), with no
6898 wasted space in the client code due to sparse flow graphs. */
6900 /* This functions initializes the edge list. Basically the entire
6901 flowgraph is processed, and all edges are assigned a number,
6902 and the data structure is filled in. */
6907 struct edge_list *elist;
6913 block_count = n_basic_blocks + 2; /* Include the entry and exit blocks. */
6917 /* Determine the number of edges in the flow graph by counting successor
6918 edges on each basic block. */
6919 for (x = 0; x < n_basic_blocks; x++)
6921 basic_block bb = BASIC_BLOCK (x);
6923 for (e = bb->succ; e; e = e->succ_next)
6926 /* Don't forget successors of the entry block. */
6927 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
6930 elist = (struct edge_list *) xmalloc (sizeof (struct edge_list));
6931 elist->num_blocks = block_count;
6932 elist->num_edges = num_edges;
6933 elist->index_to_edge = (edge *) xmalloc (sizeof (edge) * num_edges);
6937 /* Follow successors of the entry block, and register these edges. */
6938 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
6940 elist->index_to_edge[num_edges] = e;
6944 for (x = 0; x < n_basic_blocks; x++)
6946 basic_block bb = BASIC_BLOCK (x);
6948 /* Follow all successors of blocks, and register these edges. */
6949 for (e = bb->succ; e; e = e->succ_next)
6951 elist->index_to_edge[num_edges] = e;
6958 /* This function free's memory associated with an edge list. */
6961 free_edge_list (elist)
6962 struct edge_list *elist;
6966 free (elist->index_to_edge);
6971 /* This function provides debug output showing an edge list. */
6974 print_edge_list (f, elist)
6976 struct edge_list *elist;
6979 fprintf (f, "Compressed edge list, %d BBs + entry & exit, and %d edges\n",
6980 elist->num_blocks - 2, elist->num_edges);
6982 for (x = 0; x < elist->num_edges; x++)
6984 fprintf (f, " %-4d - edge(", x);
6985 if (INDEX_EDGE_PRED_BB (elist, x) == ENTRY_BLOCK_PTR)
6986 fprintf (f, "entry,");
6988 fprintf (f, "%d,", INDEX_EDGE_PRED_BB (elist, x)->index);
6990 if (INDEX_EDGE_SUCC_BB (elist, x) == EXIT_BLOCK_PTR)
6991 fprintf (f, "exit)\n");
6993 fprintf (f, "%d)\n", INDEX_EDGE_SUCC_BB (elist, x)->index);
6997 /* This function provides an internal consistency check of an edge list,
6998 verifying that all edges are present, and that there are no
7002 verify_edge_list (f, elist)
7004 struct edge_list *elist;
7006 int x, pred, succ, index;
7009 for (x = 0; x < n_basic_blocks; x++)
7011 basic_block bb = BASIC_BLOCK (x);
7013 for (e = bb->succ; e; e = e->succ_next)
7015 pred = e->src->index;
7016 succ = e->dest->index;
7017 index = EDGE_INDEX (elist, e->src, e->dest);
7018 if (index == EDGE_INDEX_NO_EDGE)
7020 fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
7023 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
7024 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
7025 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
7026 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
7027 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
7028 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
7031 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
7033 pred = e->src->index;
7034 succ = e->dest->index;
7035 index = EDGE_INDEX (elist, e->src, e->dest);
7036 if (index == EDGE_INDEX_NO_EDGE)
7038 fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
7041 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
7042 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
7043 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
7044 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
7045 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
7046 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
7048 /* We've verified that all the edges are in the list, no lets make sure
7049 there are no spurious edges in the list. */
7051 for (pred = 0; pred < n_basic_blocks; pred++)
7052 for (succ = 0; succ < n_basic_blocks; succ++)
7054 basic_block p = BASIC_BLOCK (pred);
7055 basic_block s = BASIC_BLOCK (succ);
7059 for (e = p->succ; e; e = e->succ_next)
7065 for (e = s->pred; e; e = e->pred_next)
7071 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
7072 == EDGE_INDEX_NO_EDGE && found_edge != 0)
7073 fprintf (f, "*** Edge (%d, %d) appears to not have an index\n",
7075 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
7076 != EDGE_INDEX_NO_EDGE && found_edge == 0)
7077 fprintf (f, "*** Edge (%d, %d) has index %d, but there is no edge\n",
7078 pred, succ, EDGE_INDEX (elist, BASIC_BLOCK (pred),
7079 BASIC_BLOCK (succ)));
7081 for (succ = 0; succ < n_basic_blocks; succ++)
7083 basic_block p = ENTRY_BLOCK_PTR;
7084 basic_block s = BASIC_BLOCK (succ);
7088 for (e = p->succ; e; e = e->succ_next)
7094 for (e = s->pred; e; e = e->pred_next)
7100 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
7101 == EDGE_INDEX_NO_EDGE && found_edge != 0)
7102 fprintf (f, "*** Edge (entry, %d) appears to not have an index\n",
7104 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
7105 != EDGE_INDEX_NO_EDGE && found_edge == 0)
7106 fprintf (f, "*** Edge (entry, %d) has index %d, but no edge exists\n",
7107 succ, EDGE_INDEX (elist, ENTRY_BLOCK_PTR,
7108 BASIC_BLOCK (succ)));
7110 for (pred = 0; pred < n_basic_blocks; pred++)
7112 basic_block p = BASIC_BLOCK (pred);
7113 basic_block s = EXIT_BLOCK_PTR;
7117 for (e = p->succ; e; e = e->succ_next)
7123 for (e = s->pred; e; e = e->pred_next)
7129 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
7130 == EDGE_INDEX_NO_EDGE && found_edge != 0)
7131 fprintf (f, "*** Edge (%d, exit) appears to not have an index\n",
7133 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
7134 != EDGE_INDEX_NO_EDGE && found_edge == 0)
7135 fprintf (f, "*** Edge (%d, exit) has index %d, but no edge exists\n",
7136 pred, EDGE_INDEX (elist, BASIC_BLOCK (pred),
7141 /* This routine will determine what, if any, edge there is between
7142 a specified predecessor and successor. */
7145 find_edge_index (edge_list, pred, succ)
7146 struct edge_list *edge_list;
7147 basic_block pred, succ;
7150 for (x = 0; x < NUM_EDGES (edge_list); x++)
7152 if (INDEX_EDGE_PRED_BB (edge_list, x) == pred
7153 && INDEX_EDGE_SUCC_BB (edge_list, x) == succ)
7156 return (EDGE_INDEX_NO_EDGE);
7159 /* This function will remove an edge from the flow graph. */
7165 edge last_pred = NULL;
7166 edge last_succ = NULL;
7168 basic_block src, dest;
7171 for (tmp = src->succ; tmp && tmp != e; tmp = tmp->succ_next)
7177 last_succ->succ_next = e->succ_next;
7179 src->succ = e->succ_next;
7181 for (tmp = dest->pred; tmp && tmp != e; tmp = tmp->pred_next)
7187 last_pred->pred_next = e->pred_next;
7189 dest->pred = e->pred_next;
7195 /* This routine will remove any fake successor edges for a basic block.
7196 When the edge is removed, it is also removed from whatever predecessor
7200 remove_fake_successors (bb)
7204 for (e = bb->succ; e;)
7208 if ((tmp->flags & EDGE_FAKE) == EDGE_FAKE)
7213 /* This routine will remove all fake edges from the flow graph. If
7214 we remove all fake successors, it will automatically remove all
7215 fake predecessors. */
7218 remove_fake_edges ()
7222 for (x = 0; x < n_basic_blocks; x++)
7223 remove_fake_successors (BASIC_BLOCK (x));
7225 /* We've handled all successors except the entry block's. */
7226 remove_fake_successors (ENTRY_BLOCK_PTR);
7229 /* This function will add a fake edge between any block which has no
7230 successors, and the exit block. Some data flow equations require these
7234 add_noreturn_fake_exit_edges ()
7238 for (x = 0; x < n_basic_blocks; x++)
7239 if (BASIC_BLOCK (x)->succ == NULL)
7240 make_edge (NULL, BASIC_BLOCK (x), EXIT_BLOCK_PTR, EDGE_FAKE);
7243 /* This function adds a fake edge between any infinite loops to the
7244 exit block. Some optimizations require a path from each node to
7247 See also Morgan, Figure 3.10, pp. 82-83.
7249 The current implementation is ugly, not attempting to minimize the
7250 number of inserted fake edges. To reduce the number of fake edges
7251 to insert, add fake edges from _innermost_ loops containing only
7252 nodes not reachable from the exit block. */
7255 connect_infinite_loops_to_exit ()
7257 basic_block unvisited_block;
7259 /* Perform depth-first search in the reverse graph to find nodes
7260 reachable from the exit block. */
7261 struct depth_first_search_dsS dfs_ds;
7263 flow_dfs_compute_reverse_init (&dfs_ds);
7264 flow_dfs_compute_reverse_add_bb (&dfs_ds, EXIT_BLOCK_PTR);
7266 /* Repeatedly add fake edges, updating the unreachable nodes. */
7269 unvisited_block = flow_dfs_compute_reverse_execute (&dfs_ds);
7270 if (!unvisited_block)
7272 make_edge (NULL, unvisited_block, EXIT_BLOCK_PTR, EDGE_FAKE);
7273 flow_dfs_compute_reverse_add_bb (&dfs_ds, unvisited_block);
7276 flow_dfs_compute_reverse_finish (&dfs_ds);
7281 /* Redirect an edge's successor from one block to another. */
7284 redirect_edge_succ (e, new_succ)
7286 basic_block new_succ;
7290 /* Disconnect the edge from the old successor block. */
7291 for (pe = &e->dest->pred; *pe != e; pe = &(*pe)->pred_next)
7293 *pe = (*pe)->pred_next;
7295 /* Reconnect the edge to the new successor block. */
7296 e->pred_next = new_succ->pred;
7301 /* Redirect an edge's predecessor from one block to another. */
7304 redirect_edge_pred (e, new_pred)
7306 basic_block new_pred;
7310 /* Disconnect the edge from the old predecessor block. */
7311 for (pe = &e->src->succ; *pe != e; pe = &(*pe)->succ_next)
7313 *pe = (*pe)->succ_next;
7315 /* Reconnect the edge to the new predecessor block. */
7316 e->succ_next = new_pred->succ;
7321 /* Dump the list of basic blocks in the bitmap NODES. */
7324 flow_nodes_print (str, nodes, file)
7326 const sbitmap nodes;
7334 fprintf (file, "%s { ", str);
7335 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {fprintf (file, "%d ", node);});
7336 fputs ("}\n", file);
7340 /* Dump the list of edges in the array EDGE_LIST. */
7343 flow_edge_list_print (str, edge_list, num_edges, file)
7345 const edge *edge_list;
7354 fprintf (file, "%s { ", str);
7355 for (i = 0; i < num_edges; i++)
7356 fprintf (file, "%d->%d ", edge_list[i]->src->index,
7357 edge_list[i]->dest->index);
7358 fputs ("}\n", file);
7362 /* Dump loop related CFG information. */
7365 flow_loops_cfg_dump (loops, file)
7366 const struct loops *loops;
7371 if (! loops->num || ! file || ! loops->cfg.dom)
7374 for (i = 0; i < n_basic_blocks; i++)
7378 fprintf (file, ";; %d succs { ", i);
7379 for (succ = BASIC_BLOCK (i)->succ; succ; succ = succ->succ_next)
7380 fprintf (file, "%d ", succ->dest->index);
7381 flow_nodes_print ("} dom", loops->cfg.dom[i], file);
7384 /* Dump the DFS node order. */
7385 if (loops->cfg.dfs_order)
7387 fputs (";; DFS order: ", file);
7388 for (i = 0; i < n_basic_blocks; i++)
7389 fprintf (file, "%d ", loops->cfg.dfs_order[i]);
7392 /* Dump the reverse completion node order. */
7393 if (loops->cfg.rc_order)
7395 fputs (";; RC order: ", file);
7396 for (i = 0; i < n_basic_blocks; i++)
7397 fprintf (file, "%d ", loops->cfg.rc_order[i]);
7402 /* Return non-zero if the nodes of LOOP are a subset of OUTER. */
7405 flow_loop_nested_p (outer, loop)
7409 return sbitmap_a_subset_b_p (loop->nodes, outer->nodes);
7413 /* Dump the loop information specified by LOOP to the stream FILE
7414 using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
7416 flow_loop_dump (loop, file, loop_dump_aux, verbose)
7417 const struct loop *loop;
7419 void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
7422 if (! loop || ! loop->header)
7425 fprintf (file, ";;\n;; Loop %d (%d to %d):%s%s\n",
7426 loop->num, INSN_UID (loop->first->head),
7427 INSN_UID (loop->last->end),
7428 loop->shared ? " shared" : "",
7429 loop->invalid ? " invalid" : "");
7430 fprintf (file, ";; header %d, latch %d, pre-header %d, first %d, last %d\n",
7431 loop->header->index, loop->latch->index,
7432 loop->pre_header ? loop->pre_header->index : -1,
7433 loop->first->index, loop->last->index);
7434 fprintf (file, ";; depth %d, level %d, outer %ld\n",
7435 loop->depth, loop->level,
7436 (long) (loop->outer ? loop->outer->num : -1));
7438 if (loop->pre_header_edges)
7439 flow_edge_list_print (";; pre-header edges", loop->pre_header_edges,
7440 loop->num_pre_header_edges, file);
7441 flow_edge_list_print (";; entry edges", loop->entry_edges,
7442 loop->num_entries, file);
7443 fprintf (file, ";; %d", loop->num_nodes);
7444 flow_nodes_print (" nodes", loop->nodes, file);
7445 flow_edge_list_print (";; exit edges", loop->exit_edges,
7446 loop->num_exits, file);
7447 if (loop->exits_doms)
7448 flow_nodes_print (";; exit doms", loop->exits_doms, file);
7450 loop_dump_aux (loop, file, verbose);
7454 /* Dump the loop information specified by LOOPS to the stream FILE,
7455 using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
7457 flow_loops_dump (loops, file, loop_dump_aux, verbose)
7458 const struct loops *loops;
7460 void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
7466 num_loops = loops->num;
7467 if (! num_loops || ! file)
7470 fprintf (file, ";; %d loops found, %d levels\n",
7471 num_loops, loops->levels);
7473 for (i = 0; i < num_loops; i++)
7475 struct loop *loop = &loops->array[i];
7477 flow_loop_dump (loop, file, loop_dump_aux, verbose);
7483 for (j = 0; j < i; j++)
7485 struct loop *oloop = &loops->array[j];
7487 if (loop->header == oloop->header)
7492 smaller = loop->num_nodes < oloop->num_nodes;
7494 /* If the union of LOOP and OLOOP is different than
7495 the larger of LOOP and OLOOP then LOOP and OLOOP
7496 must be disjoint. */
7497 disjoint = ! flow_loop_nested_p (smaller ? loop : oloop,
7498 smaller ? oloop : loop);
7500 ";; loop header %d shared by loops %d, %d %s\n",
7501 loop->header->index, i, j,
7502 disjoint ? "disjoint" : "nested");
7509 flow_loops_cfg_dump (loops, file);
7513 /* Free all the memory allocated for LOOPS. */
7516 flow_loops_free (loops)
7517 struct loops *loops;
7526 /* Free the loop descriptors. */
7527 for (i = 0; i < loops->num; i++)
7529 struct loop *loop = &loops->array[i];
7531 if (loop->pre_header_edges)
7532 free (loop->pre_header_edges);
7534 sbitmap_free (loop->nodes);
7535 if (loop->entry_edges)
7536 free (loop->entry_edges);
7537 if (loop->exit_edges)
7538 free (loop->exit_edges);
7539 if (loop->exits_doms)
7540 sbitmap_free (loop->exits_doms);
7542 free (loops->array);
7543 loops->array = NULL;
7546 sbitmap_vector_free (loops->cfg.dom);
7547 if (loops->cfg.dfs_order)
7548 free (loops->cfg.dfs_order);
7550 if (loops->shared_headers)
7551 sbitmap_free (loops->shared_headers);
7556 /* Find the entry edges into the loop with header HEADER and nodes
7557 NODES and store in ENTRY_EDGES array. Return the number of entry
7558 edges from the loop. */
7561 flow_loop_entry_edges_find (header, nodes, entry_edges)
7563 const sbitmap nodes;
7569 *entry_edges = NULL;
7572 for (e = header->pred; e; e = e->pred_next)
7574 basic_block src = e->src;
7576 if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
7583 *entry_edges = (edge *) xmalloc (num_entries * sizeof (edge *));
7586 for (e = header->pred; e; e = e->pred_next)
7588 basic_block src = e->src;
7590 if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
7591 (*entry_edges)[num_entries++] = e;
7598 /* Find the exit edges from the loop using the bitmap of loop nodes
7599 NODES and store in EXIT_EDGES array. Return the number of
7600 exit edges from the loop. */
7603 flow_loop_exit_edges_find (nodes, exit_edges)
7604 const sbitmap nodes;
7613 /* Check all nodes within the loop to see if there are any
7614 successors not in the loop. Note that a node may have multiple
7615 exiting edges ????? A node can have one jumping edge and one fallthru
7616 edge so only one of these can exit the loop. */
7618 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
7619 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
7621 basic_block dest = e->dest;
7623 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
7631 *exit_edges = (edge *) xmalloc (num_exits * sizeof (edge *));
7633 /* Store all exiting edges into an array. */
7635 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
7636 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
7638 basic_block dest = e->dest;
7640 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
7641 (*exit_edges)[num_exits++] = e;
7649 /* Find the nodes contained within the loop with header HEADER and
7650 latch LATCH and store in NODES. Return the number of nodes within
7654 flow_loop_nodes_find (header, latch, nodes)
7663 stack = (basic_block *) xmalloc (n_basic_blocks * sizeof (basic_block));
7666 /* Start with only the loop header in the set of loop nodes. */
7667 sbitmap_zero (nodes);
7668 SET_BIT (nodes, header->index);
7670 header->loop_depth++;
7672 /* Push the loop latch on to the stack. */
7673 if (! TEST_BIT (nodes, latch->index))
7675 SET_BIT (nodes, latch->index);
7676 latch->loop_depth++;
7678 stack[sp++] = latch;
7687 for (e = node->pred; e; e = e->pred_next)
7689 basic_block ancestor = e->src;
7691 /* If each ancestor not marked as part of loop, add to set of
7692 loop nodes and push on to stack. */
7693 if (ancestor != ENTRY_BLOCK_PTR
7694 && ! TEST_BIT (nodes, ancestor->index))
7696 SET_BIT (nodes, ancestor->index);
7697 ancestor->loop_depth++;
7699 stack[sp++] = ancestor;
7707 /* Compute the depth first search order and store in the array
7708 DFS_ORDER if non-zero, marking the nodes visited in VISITED. If
7709 RC_ORDER is non-zero, return the reverse completion number for each
7710 node. Returns the number of nodes visited. A depth first search
7711 tries to get as far away from the starting point as quickly as
7715 flow_depth_first_order_compute (dfs_order, rc_order)
7722 int rcnum = n_basic_blocks - 1;
7725 /* Allocate stack for back-tracking up CFG. */
7726 stack = (edge *) xmalloc ((n_basic_blocks + 1) * sizeof (edge));
7729 /* Allocate bitmap to track nodes that have been visited. */
7730 visited = sbitmap_alloc (n_basic_blocks);
7732 /* None of the nodes in the CFG have been visited yet. */
7733 sbitmap_zero (visited);
7735 /* Push the first edge on to the stack. */
7736 stack[sp++] = ENTRY_BLOCK_PTR->succ;
7744 /* Look at the edge on the top of the stack. */
7749 /* Check if the edge destination has been visited yet. */
7750 if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index))
7752 /* Mark that we have visited the destination. */
7753 SET_BIT (visited, dest->index);
7756 dfs_order[dfsnum++] = dest->index;
7760 /* Since the DEST node has been visited for the first
7761 time, check its successors. */
7762 stack[sp++] = dest->succ;
7766 /* There are no successors for the DEST node so assign
7767 its reverse completion number. */
7769 rc_order[rcnum--] = dest->index;
7774 if (! e->succ_next && src != ENTRY_BLOCK_PTR)
7776 /* There are no more successors for the SRC node
7777 so assign its reverse completion number. */
7779 rc_order[rcnum--] = src->index;
7783 stack[sp - 1] = e->succ_next;
7790 sbitmap_free (visited);
7792 /* The number of nodes visited should not be greater than
7794 if (dfsnum > n_basic_blocks)
7797 /* There are some nodes left in the CFG that are unreachable. */
7798 if (dfsnum < n_basic_blocks)
7803 /* Compute the depth first search order on the _reverse_ graph and
7804 store in the array DFS_ORDER, marking the nodes visited in VISITED.
7805 Returns the number of nodes visited.
7807 The computation is split into three pieces:
7809 flow_dfs_compute_reverse_init () creates the necessary data
7812 flow_dfs_compute_reverse_add_bb () adds a basic block to the data
7813 structures. The block will start the search.
7815 flow_dfs_compute_reverse_execute () continues (or starts) the
7816 search using the block on the top of the stack, stopping when the
7819 flow_dfs_compute_reverse_finish () destroys the necessary data
7822 Thus, the user will probably call ..._init(), call ..._add_bb() to
7823 add a beginning basic block to the stack, call ..._execute(),
7824 possibly add another bb to the stack and again call ..._execute(),
7825 ..., and finally call _finish(). */
7827 /* Initialize the data structures used for depth-first search on the
7828 reverse graph. If INITIALIZE_STACK is nonzero, the exit block is
7829 added to the basic block stack. DATA is the current depth-first
7830 search context. If INITIALIZE_STACK is non-zero, there is an
7831 element on the stack. */
7834 flow_dfs_compute_reverse_init (data)
7835 depth_first_search_ds data;
7837 /* Allocate stack for back-tracking up CFG. */
7839 (basic_block *) xmalloc ((n_basic_blocks - (INVALID_BLOCK + 1))
7840 * sizeof (basic_block));
7843 /* Allocate bitmap to track nodes that have been visited. */
7844 data->visited_blocks = sbitmap_alloc (n_basic_blocks - (INVALID_BLOCK + 1));
7846 /* None of the nodes in the CFG have been visited yet. */
7847 sbitmap_zero (data->visited_blocks);
7852 /* Add the specified basic block to the top of the dfs data
7853 structures. When the search continues, it will start at the
7857 flow_dfs_compute_reverse_add_bb (data, bb)
7858 depth_first_search_ds data;
7861 data->stack[data->sp++] = bb;
7865 /* Continue the depth-first search through the reverse graph starting
7866 with the block at the stack's top and ending when the stack is
7867 empty. Visited nodes are marked. Returns an unvisited basic
7868 block, or NULL if there is none available. */
7871 flow_dfs_compute_reverse_execute (data)
7872 depth_first_search_ds data;
7878 while (data->sp > 0)
7880 bb = data->stack[--data->sp];
7882 /* Mark that we have visited this node. */
7883 if (!TEST_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1)))
7885 SET_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1));
7887 /* Perform depth-first search on adjacent vertices. */
7888 for (e = bb->pred; e; e = e->pred_next)
7889 flow_dfs_compute_reverse_add_bb (data, e->src);
7893 /* Determine if there are unvisited basic blocks. */
7894 for (i = n_basic_blocks - (INVALID_BLOCK + 1); --i >= 0;)
7895 if (!TEST_BIT (data->visited_blocks, i))
7896 return BASIC_BLOCK (i + (INVALID_BLOCK + 1));
7900 /* Destroy the data structures needed for depth-first search on the
7904 flow_dfs_compute_reverse_finish (data)
7905 depth_first_search_ds data;
7908 sbitmap_free (data->visited_blocks);
7913 /* Find the root node of the loop pre-header extended basic block and
7914 the edges along the trace from the root node to the loop header. */
7917 flow_loop_pre_header_scan (loop)
7923 loop->num_pre_header_edges = 0;
7925 if (loop->num_entries != 1)
7928 ebb = loop->entry_edges[0]->src;
7930 if (ebb != ENTRY_BLOCK_PTR)
7934 /* Count number of edges along trace from loop header to
7935 root of pre-header extended basic block. Usually this is
7936 only one or two edges. */
7938 while (ebb->pred->src != ENTRY_BLOCK_PTR && ! ebb->pred->pred_next)
7940 ebb = ebb->pred->src;
7944 loop->pre_header_edges = (edge *) xmalloc (num * sizeof (edge *));
7945 loop->num_pre_header_edges = num;
7947 /* Store edges in order that they are followed. The source
7948 of the first edge is the root node of the pre-header extended
7949 basic block and the destination of the last last edge is
7951 for (e = loop->entry_edges[0]; num; e = e->src->pred)
7953 loop->pre_header_edges[--num] = e;
7959 /* Return the block for the pre-header of the loop with header
7960 HEADER where DOM specifies the dominator information. Return NULL if
7961 there is no pre-header. */
7964 flow_loop_pre_header_find (header, dom)
7968 basic_block pre_header;
7971 /* If block p is a predecessor of the header and is the only block
7972 that the header does not dominate, then it is the pre-header. */
7974 for (e = header->pred; e; e = e->pred_next)
7976 basic_block node = e->src;
7978 if (node != ENTRY_BLOCK_PTR
7979 && ! TEST_BIT (dom[node->index], header->index))
7981 if (pre_header == NULL)
7985 /* There are multiple edges into the header from outside
7986 the loop so there is no pre-header block. */
7995 /* Add LOOP to the loop hierarchy tree where PREVLOOP was the loop
7996 previously added. The insertion algorithm assumes that the loops
7997 are added in the order found by a depth first search of the CFG. */
8000 flow_loop_tree_node_add (prevloop, loop)
8001 struct loop *prevloop;
8005 if (flow_loop_nested_p (prevloop, loop))
8007 prevloop->inner = loop;
8008 loop->outer = prevloop;
8012 while (prevloop->outer)
8014 if (flow_loop_nested_p (prevloop->outer, loop))
8016 prevloop->next = loop;
8017 loop->outer = prevloop->outer;
8020 prevloop = prevloop->outer;
8023 prevloop->next = loop;
8027 /* Build the loop hierarchy tree for LOOPS. */
8030 flow_loops_tree_build (loops)
8031 struct loops *loops;
8036 num_loops = loops->num;
8040 /* Root the loop hierarchy tree with the first loop found.
8041 Since we used a depth first search this should be the
8043 loops->tree = &loops->array[0];
8044 loops->tree->outer = loops->tree->inner = loops->tree->next = NULL;
8046 /* Add the remaining loops to the tree. */
8047 for (i = 1; i < num_loops; i++)
8048 flow_loop_tree_node_add (&loops->array[i - 1], &loops->array[i]);
8051 /* Helper function to compute loop nesting depth and enclosed loop level
8052 for the natural loop specified by LOOP at the loop depth DEPTH.
8053 Returns the loop level. */
8056 flow_loop_level_compute (loop, depth)
8066 /* Traverse loop tree assigning depth and computing level as the
8067 maximum level of all the inner loops of this loop. The loop
8068 level is equivalent to the height of the loop in the loop tree
8069 and corresponds to the number of enclosed loop levels (including
8071 for (inner = loop->inner; inner; inner = inner->next)
8075 ilevel = flow_loop_level_compute (inner, depth + 1) + 1;
8080 loop->level = level;
8081 loop->depth = depth;
8085 /* Compute the loop nesting depth and enclosed loop level for the loop
8086 hierarchy tree specfied by LOOPS. Return the maximum enclosed loop
8090 flow_loops_level_compute (loops)
8091 struct loops *loops;
8097 /* Traverse all the outer level loops. */
8098 for (loop = loops->tree; loop; loop = loop->next)
8100 level = flow_loop_level_compute (loop, 1);
8108 /* Find all the natural loops in the function and save in LOOPS structure
8109 and recalculate loop_depth information in basic block structures.
8110 FLAGS controls which loop information is collected.
8111 Return the number of natural loops found. */
8114 flow_loops_find (loops, flags)
8115 struct loops *loops;
8127 /* This function cannot be repeatedly called with different
8128 flags to build up the loop information. The loop tree
8129 must always be built if this function is called. */
8130 if (! (flags & LOOP_TREE))
8133 memset (loops, 0, sizeof (*loops));
8135 /* Taking care of this degenerate case makes the rest of
8136 this code simpler. */
8137 if (n_basic_blocks == 0)
8143 /* Compute the dominators. */
8144 dom = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
8145 calculate_dominance_info (NULL, dom, CDI_DOMINATORS);
8147 /* Count the number of loop edges (back edges). This should be the
8148 same as the number of natural loops. */
8151 for (b = 0; b < n_basic_blocks; b++)
8155 header = BASIC_BLOCK (b);
8156 header->loop_depth = 0;
8158 for (e = header->pred; e; e = e->pred_next)
8160 basic_block latch = e->src;
8162 /* Look for back edges where a predecessor is dominated
8163 by this block. A natural loop has a single entry
8164 node (header) that dominates all the nodes in the
8165 loop. It also has single back edge to the header
8166 from a latch node. Note that multiple natural loops
8167 may share the same header. */
8168 if (b != header->index)
8171 if (latch != ENTRY_BLOCK_PTR && TEST_BIT (dom[latch->index], b))
8178 /* Compute depth first search order of the CFG so that outer
8179 natural loops will be found before inner natural loops. */
8180 dfs_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
8181 rc_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
8182 flow_depth_first_order_compute (dfs_order, rc_order);
8184 /* Allocate loop structures. */
8186 = (struct loop *) xcalloc (num_loops, sizeof (struct loop));
8188 headers = sbitmap_alloc (n_basic_blocks);
8189 sbitmap_zero (headers);
8191 loops->shared_headers = sbitmap_alloc (n_basic_blocks);
8192 sbitmap_zero (loops->shared_headers);
8194 /* Find and record information about all the natural loops
8197 for (b = 0; b < n_basic_blocks; b++)
8201 /* Search the nodes of the CFG in reverse completion order
8202 so that we can find outer loops first. */
8203 header = BASIC_BLOCK (rc_order[b]);
8205 /* Look for all the possible latch blocks for this header. */
8206 for (e = header->pred; e; e = e->pred_next)
8208 basic_block latch = e->src;
8210 /* Look for back edges where a predecessor is dominated
8211 by this block. A natural loop has a single entry
8212 node (header) that dominates all the nodes in the
8213 loop. It also has single back edge to the header
8214 from a latch node. Note that multiple natural loops
8215 may share the same header. */
8216 if (latch != ENTRY_BLOCK_PTR
8217 && TEST_BIT (dom[latch->index], header->index))
8221 loop = loops->array + num_loops;
8223 loop->header = header;
8224 loop->latch = latch;
8225 loop->num = num_loops;
8232 for (i = 0; i < num_loops; i++)
8234 struct loop *loop = &loops->array[i];
8237 /* Keep track of blocks that are loop headers so
8238 that we can tell which loops should be merged. */
8239 if (TEST_BIT (headers, loop->header->index))
8240 SET_BIT (loops->shared_headers, loop->header->index);
8241 SET_BIT (headers, loop->header->index);
8243 /* Find nodes contained within the loop. */
8244 loop->nodes = sbitmap_alloc (n_basic_blocks);
8246 = flow_loop_nodes_find (loop->header, loop->latch, loop->nodes);
8248 /* Compute first and last blocks within the loop.
8249 These are often the same as the loop header and
8250 loop latch respectively, but this is not always
8253 = BASIC_BLOCK (sbitmap_first_set_bit (loop->nodes));
8255 = BASIC_BLOCK (sbitmap_last_set_bit (loop->nodes));
8257 if (flags & LOOP_EDGES)
8259 /* Find edges which enter the loop header.
8260 Note that the entry edges should only
8261 enter the header of a natural loop. */
8263 = flow_loop_entry_edges_find (loop->header,
8265 &loop->entry_edges);
8267 /* Find edges which exit the loop. */
8269 = flow_loop_exit_edges_find (loop->nodes,
8272 /* Determine which loop nodes dominate all the exits
8274 loop->exits_doms = sbitmap_alloc (n_basic_blocks);
8275 sbitmap_copy (loop->exits_doms, loop->nodes);
8276 for (j = 0; j < loop->num_exits; j++)
8277 sbitmap_a_and_b (loop->exits_doms, loop->exits_doms,
8278 dom[loop->exit_edges[j]->src->index]);
8280 /* The header of a natural loop must dominate
8282 if (! TEST_BIT (loop->exits_doms, loop->header->index))
8286 if (flags & LOOP_PRE_HEADER)
8288 /* Look to see if the loop has a pre-header node. */
8290 = flow_loop_pre_header_find (loop->header, dom);
8292 flow_loop_pre_header_scan (loop);
8296 /* Natural loops with shared headers may either be disjoint or
8297 nested. Disjoint loops with shared headers cannot be inner
8298 loops and should be merged. For now just mark loops that share
8300 for (i = 0; i < num_loops; i++)
8301 if (TEST_BIT (loops->shared_headers, loops->array[i].header->index))
8302 loops->array[i].shared = 1;
8304 sbitmap_free (headers);
8307 loops->num = num_loops;
8309 /* Save CFG derived information to avoid recomputing it. */
8310 loops->cfg.dom = dom;
8311 loops->cfg.dfs_order = dfs_order;
8312 loops->cfg.rc_order = rc_order;
8314 /* Build the loop hierarchy tree. */
8315 flow_loops_tree_build (loops);
8317 /* Assign the loop nesting depth and enclosed loop level for each
8319 loops->levels = flow_loops_level_compute (loops);
8325 /* Update the information regarding the loops in the CFG
8326 specified by LOOPS. */
8328 flow_loops_update (loops, flags)
8329 struct loops *loops;
8332 /* One day we may want to update the current loop data. For now
8333 throw away the old stuff and rebuild what we need. */
8335 flow_loops_free (loops);
8337 return flow_loops_find (loops, flags);
8341 /* Return non-zero if edge E enters header of LOOP from outside of LOOP. */
8344 flow_loop_outside_edge_p (loop, e)
8345 const struct loop *loop;
8348 if (e->dest != loop->header)
8350 return (e->src == ENTRY_BLOCK_PTR)
8351 || ! TEST_BIT (loop->nodes, e->src->index);
8354 /* Clear LOG_LINKS fields of insns in a chain.
8355 Also clear the global_live_at_{start,end} fields of the basic block
8359 clear_log_links (insns)
8365 for (i = insns; i; i = NEXT_INSN (i))
8369 for (b = 0; b < n_basic_blocks; b++)
8371 basic_block bb = BASIC_BLOCK (b);
8373 bb->global_live_at_start = NULL;
8374 bb->global_live_at_end = NULL;
8377 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
8378 EXIT_BLOCK_PTR->global_live_at_start = NULL;
8381 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
8382 correspond to the hard registers, if any, set in that map. This
8383 could be done far more efficiently by having all sorts of special-cases
8384 with moving single words, but probably isn't worth the trouble. */
8387 reg_set_to_hard_reg_set (to, from)
8393 EXECUTE_IF_SET_IN_BITMAP
8396 if (i >= FIRST_PSEUDO_REGISTER)
8398 SET_HARD_REG_BIT (*to, i);
8402 /* Called once at intialization time. */
8407 static int initialized;
8411 gcc_obstack_init (&flow_obstack);
8412 flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);
8417 obstack_free (&flow_obstack, flow_firstobj);
8418 flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);