1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001 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"
140 #include "splay-tree.h"
142 #define obstack_chunk_alloc xmalloc
143 #define obstack_chunk_free free
145 /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
146 the stack pointer does not matter. The value is tested only in
147 functions that have frame pointers.
148 No definition is equivalent to always zero. */
149 #ifndef EXIT_IGNORE_STACK
150 #define EXIT_IGNORE_STACK 0
153 #ifndef HAVE_epilogue
154 #define HAVE_epilogue 0
156 #ifndef HAVE_prologue
157 #define HAVE_prologue 0
159 #ifndef HAVE_sibcall_epilogue
160 #define HAVE_sibcall_epilogue 0
164 #define LOCAL_REGNO(REGNO) 0
166 #ifndef EPILOGUE_USES
167 #define EPILOGUE_USES(REGNO) 0
170 #ifdef HAVE_conditional_execution
171 #ifndef REVERSE_CONDEXEC_PREDICATES_P
172 #define REVERSE_CONDEXEC_PREDICATES_P(x, y) ((x) == reverse_condition (y))
176 /* The obstack on which the flow graph components are allocated. */
178 struct obstack flow_obstack;
179 static char *flow_firstobj;
181 /* Number of basic blocks in the current function. */
185 /* Number of edges in the current function. */
189 /* The basic block array. */
191 varray_type basic_block_info;
193 /* The special entry and exit blocks. */
195 struct basic_block_def entry_exit_blocks[2]
200 NULL, /* local_set */
201 NULL, /* cond_local_set */
202 NULL, /* global_live_at_start */
203 NULL, /* global_live_at_end */
205 ENTRY_BLOCK, /* index */
207 -1, -1, /* eh_beg, eh_end */
215 NULL, /* local_set */
216 NULL, /* cond_local_set */
217 NULL, /* global_live_at_start */
218 NULL, /* global_live_at_end */
220 EXIT_BLOCK, /* index */
222 -1, -1, /* eh_beg, eh_end */
227 /* Nonzero if the second flow pass has completed. */
230 /* Maximum register number used in this function, plus one. */
234 /* Indexed by n, giving various register information */
236 varray_type reg_n_info;
238 /* Size of a regset for the current function,
239 in (1) bytes and (2) elements. */
244 /* Regset of regs live when calls to `setjmp'-like functions happen. */
245 /* ??? Does this exist only for the setjmp-clobbered warning message? */
247 regset regs_live_at_setjmp;
249 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
250 that have to go in the same hard reg.
251 The first two regs in the list are a pair, and the next two
252 are another pair, etc. */
255 /* Callback that determines if it's ok for a function to have no
256 noreturn attribute. */
257 int (*lang_missing_noreturn_ok_p) PARAMS ((tree));
259 /* Set of registers that may be eliminable. These are handled specially
260 in updating regs_ever_live. */
262 static HARD_REG_SET elim_reg_set;
264 /* The basic block structure for every insn, indexed by uid. */
266 varray_type basic_block_for_insn;
268 /* The labels mentioned in non-jump rtl. Valid during find_basic_blocks. */
269 /* ??? Should probably be using LABEL_NUSES instead. It would take a
270 bit of surgery to be able to use or co-opt the routines in jump. */
272 static rtx label_value_list;
273 static rtx tail_recursion_label_list;
275 /* Holds information for tracking conditional register life information. */
276 struct reg_cond_life_info
278 /* A boolean expression of conditions under which a register is dead. */
280 /* Conditions under which a register is dead at the basic block end. */
283 /* A boolean expression of conditions under which a register has been
287 /* ??? Could store mask of bytes that are dead, so that we could finally
288 track lifetimes of multi-word registers accessed via subregs. */
291 /* For use in communicating between propagate_block and its subroutines.
292 Holds all information needed to compute life and def-use information. */
294 struct propagate_block_info
296 /* The basic block we're considering. */
299 /* Bit N is set if register N is conditionally or unconditionally live. */
302 /* Bit N is set if register N is set this insn. */
305 /* Element N is the next insn that uses (hard or pseudo) register N
306 within the current basic block; or zero, if there is no such insn. */
309 /* Contains a list of all the MEMs we are tracking for dead store
313 /* If non-null, record the set of registers set unconditionally in the
317 /* If non-null, record the set of registers set conditionally in the
319 regset cond_local_set;
321 #ifdef HAVE_conditional_execution
322 /* Indexed by register number, holds a reg_cond_life_info for each
323 register that is not unconditionally live or dead. */
324 splay_tree reg_cond_dead;
326 /* Bit N is set if register N is in an expression in reg_cond_dead. */
330 /* The length of mem_set_list. */
331 int mem_set_list_len;
333 /* Non-zero if the value of CC0 is live. */
336 /* Flags controling the set of information propagate_block collects. */
340 /* Maximum length of pbi->mem_set_list before we start dropping
341 new elements on the floor. */
342 #define MAX_MEM_SET_LIST_LEN 100
344 /* Store the data structures necessary for depth-first search. */
345 struct depth_first_search_dsS {
346 /* stack for backtracking during the algorithm */
349 /* number of edges in the stack. That is, positions 0, ..., sp-1
353 /* record of basic blocks already seen by depth-first search */
354 sbitmap visited_blocks;
356 typedef struct depth_first_search_dsS *depth_first_search_ds;
358 /* Have print_rtl_and_abort give the same information that fancy_abort
360 #define print_rtl_and_abort() \
361 print_rtl_and_abort_fcn (__FILE__, __LINE__, __FUNCTION__)
363 /* Forward declarations */
364 static int count_basic_blocks PARAMS ((rtx));
365 static void find_basic_blocks_1 PARAMS ((rtx));
366 static rtx find_label_refs PARAMS ((rtx, rtx));
367 static void clear_edges PARAMS ((void));
368 static void make_edges PARAMS ((rtx));
369 static void make_label_edge PARAMS ((sbitmap *, basic_block,
371 static void make_eh_edge PARAMS ((sbitmap *, eh_nesting_info *,
372 basic_block, rtx, int));
373 static void mark_critical_edges PARAMS ((void));
374 static void move_stray_eh_region_notes PARAMS ((void));
375 static void record_active_eh_regions PARAMS ((rtx));
377 static void commit_one_edge_insertion PARAMS ((edge));
379 static void delete_unreachable_blocks PARAMS ((void));
380 static void delete_eh_regions PARAMS ((void));
381 static int can_delete_note_p PARAMS ((rtx));
382 static void expunge_block PARAMS ((basic_block));
383 static int can_delete_label_p PARAMS ((rtx));
384 static int tail_recursion_label_p PARAMS ((rtx));
385 static int merge_blocks_move_predecessor_nojumps PARAMS ((basic_block,
387 static int merge_blocks_move_successor_nojumps PARAMS ((basic_block,
389 static int merge_blocks PARAMS ((edge,basic_block,basic_block));
390 static void try_merge_blocks PARAMS ((void));
391 static void tidy_fallthru_edges PARAMS ((void));
392 static int verify_wide_reg_1 PARAMS ((rtx *, void *));
393 static void verify_wide_reg PARAMS ((int, rtx, rtx));
394 static void verify_local_live_at_start PARAMS ((regset, basic_block));
395 static int set_noop_p PARAMS ((rtx));
396 static int noop_move_p PARAMS ((rtx));
397 static void delete_noop_moves PARAMS ((rtx));
398 static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
399 static void notice_stack_pointer_modification PARAMS ((rtx));
400 static void mark_reg PARAMS ((rtx, void *));
401 static void mark_regs_live_at_end PARAMS ((regset));
402 static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
403 static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
404 static void propagate_block_delete_insn PARAMS ((basic_block, rtx));
405 static rtx propagate_block_delete_libcall PARAMS ((basic_block, rtx, rtx));
406 static int insn_dead_p PARAMS ((struct propagate_block_info *,
408 static int libcall_dead_p PARAMS ((struct propagate_block_info *,
410 static void mark_set_regs PARAMS ((struct propagate_block_info *,
412 static void mark_set_1 PARAMS ((struct propagate_block_info *,
413 enum rtx_code, rtx, rtx,
415 #ifdef HAVE_conditional_execution
416 static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
418 static void free_reg_cond_life_info PARAMS ((splay_tree_value));
419 static int flush_reg_cond_reg_1 PARAMS ((splay_tree_node, void *));
420 static void flush_reg_cond_reg PARAMS ((struct propagate_block_info *,
422 static rtx elim_reg_cond PARAMS ((rtx, unsigned int));
423 static rtx ior_reg_cond PARAMS ((rtx, rtx, int));
424 static rtx not_reg_cond PARAMS ((rtx));
425 static rtx and_reg_cond PARAMS ((rtx, rtx, int));
428 static void attempt_auto_inc PARAMS ((struct propagate_block_info *,
429 rtx, rtx, rtx, rtx, rtx));
430 static void find_auto_inc PARAMS ((struct propagate_block_info *,
432 static int try_pre_increment_1 PARAMS ((struct propagate_block_info *,
434 static int try_pre_increment PARAMS ((rtx, rtx, HOST_WIDE_INT));
436 static void mark_used_reg PARAMS ((struct propagate_block_info *,
438 static void mark_used_regs PARAMS ((struct propagate_block_info *,
440 void dump_flow_info PARAMS ((FILE *));
441 void debug_flow_info PARAMS ((void));
442 static void dump_edge_info PARAMS ((FILE *, edge, int));
443 static void print_rtl_and_abort_fcn PARAMS ((const char *, int,
447 static void invalidate_mems_from_autoinc PARAMS ((struct propagate_block_info *,
449 static void invalidate_mems_from_set PARAMS ((struct propagate_block_info *,
451 static void remove_fake_successors PARAMS ((basic_block));
452 static void flow_nodes_print PARAMS ((const char *, const sbitmap,
454 static void flow_edge_list_print PARAMS ((const char *, const edge *,
456 static void flow_loops_cfg_dump PARAMS ((const struct loops *,
458 static int flow_loop_nested_p PARAMS ((struct loop *,
460 static int flow_loop_entry_edges_find PARAMS ((basic_block, const sbitmap,
462 static int flow_loop_exit_edges_find PARAMS ((const sbitmap, edge **));
463 static int flow_loop_nodes_find PARAMS ((basic_block, basic_block, sbitmap));
464 static int flow_depth_first_order_compute PARAMS ((int *, int *));
465 static void flow_dfs_compute_reverse_init
466 PARAMS ((depth_first_search_ds));
467 static void flow_dfs_compute_reverse_add_bb
468 PARAMS ((depth_first_search_ds, basic_block));
469 static basic_block flow_dfs_compute_reverse_execute
470 PARAMS ((depth_first_search_ds));
471 static void flow_dfs_compute_reverse_finish
472 PARAMS ((depth_first_search_ds));
473 static void flow_loop_pre_header_scan PARAMS ((struct loop *));
474 static basic_block flow_loop_pre_header_find PARAMS ((basic_block,
476 static void flow_loop_tree_node_add PARAMS ((struct loop *, struct loop *));
477 static void flow_loops_tree_build PARAMS ((struct loops *));
478 static int flow_loop_level_compute PARAMS ((struct loop *, int));
479 static int flow_loops_level_compute PARAMS ((struct loops *));
480 static void allocate_bb_life_data PARAMS ((void));
481 static void find_sub_basic_blocks PARAMS ((basic_block));
483 /* Find basic blocks of the current function.
484 F is the first insn of the function and NREGS the number of register
488 find_basic_blocks (f, nregs, file)
490 int nregs ATTRIBUTE_UNUSED;
491 FILE *file ATTRIBUTE_UNUSED;
495 /* Flush out existing data. */
496 if (basic_block_info != NULL)
502 /* Clear bb->aux on all extant basic blocks. We'll use this as a
503 tag for reuse during create_basic_block, just in case some pass
504 copies around basic block notes improperly. */
505 for (i = 0; i < n_basic_blocks; ++i)
506 BASIC_BLOCK (i)->aux = NULL;
508 VARRAY_FREE (basic_block_info);
511 n_basic_blocks = count_basic_blocks (f);
513 /* Size the basic block table. The actual structures will be allocated
514 by find_basic_blocks_1, since we want to keep the structure pointers
515 stable across calls to find_basic_blocks. */
516 /* ??? This whole issue would be much simpler if we called find_basic_blocks
517 exactly once, and thereafter we don't have a single long chain of
518 instructions at all until close to the end of compilation when we
519 actually lay them out. */
521 VARRAY_BB_INIT (basic_block_info, n_basic_blocks, "basic_block_info");
523 find_basic_blocks_1 (f);
525 /* Record the block to which an insn belongs. */
526 /* ??? This should be done another way, by which (perhaps) a label is
527 tagged directly with the basic block that it starts. It is used for
528 more than that currently, but IMO that is the only valid use. */
530 max_uid = get_max_uid ();
532 /* Leave space for insns life_analysis makes in some cases for auto-inc.
533 These cases are rare, so we don't need too much space. */
534 max_uid += max_uid / 10;
537 compute_bb_for_insn (max_uid);
539 /* Discover the edges of our cfg. */
540 record_active_eh_regions (f);
541 make_edges (label_value_list);
543 /* Do very simple cleanup now, for the benefit of code that runs between
544 here and cleanup_cfg, e.g. thread_prologue_and_epilogue_insns. */
545 tidy_fallthru_edges ();
547 mark_critical_edges ();
549 #ifdef ENABLE_CHECKING
555 check_function_return_warnings ()
557 if (warn_missing_noreturn
558 && !TREE_THIS_VOLATILE (cfun->decl)
559 && EXIT_BLOCK_PTR->pred == NULL
560 && (lang_missing_noreturn_ok_p
561 && !lang_missing_noreturn_ok_p (cfun->decl)))
562 warning ("function might be possible candidate for attribute `noreturn'");
564 /* If we have a path to EXIT, then we do return. */
565 if (TREE_THIS_VOLATILE (cfun->decl)
566 && EXIT_BLOCK_PTR->pred != NULL)
567 warning ("`noreturn' function does return");
569 /* If the clobber_return_insn appears in some basic block, then we
570 do reach the end without returning a value. */
571 else if (warn_return_type
572 && cfun->x_clobber_return_insn != NULL
573 && EXIT_BLOCK_PTR->pred != NULL)
575 int max_uid = get_max_uid ();
577 /* If clobber_return_insn was excised by jump1, then renumber_insns
578 can make max_uid smaller than the number still recorded in our rtx.
579 That's fine, since this is a quick way of verifying that the insn
580 is no longer in the chain. */
581 if (INSN_UID (cfun->x_clobber_return_insn) < max_uid)
583 /* Recompute insn->block mapping, since the initial mapping is
584 set before we delete unreachable blocks. */
585 compute_bb_for_insn (max_uid);
587 if (BLOCK_FOR_INSN (cfun->x_clobber_return_insn) != NULL)
588 warning ("control reaches end of non-void function");
593 /* Count the basic blocks of the function. */
596 count_basic_blocks (f)
600 register RTX_CODE prev_code;
601 register int count = 0;
603 int call_had_abnormal_edge = 0;
605 prev_code = JUMP_INSN;
606 for (insn = f; insn; insn = NEXT_INSN (insn))
608 register RTX_CODE code = GET_CODE (insn);
610 if (code == CODE_LABEL
611 || (GET_RTX_CLASS (code) == 'i'
612 && (prev_code == JUMP_INSN
613 || prev_code == BARRIER
614 || (prev_code == CALL_INSN && call_had_abnormal_edge))))
617 /* Record whether this call created an edge. */
618 if (code == CALL_INSN)
620 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
621 int region = (note ? INTVAL (XEXP (note, 0)) : 1);
623 call_had_abnormal_edge = 0;
625 /* If there is an EH region or rethrow, we have an edge. */
626 if ((eh_region && region > 0)
627 || find_reg_note (insn, REG_EH_RETHROW, NULL_RTX))
628 call_had_abnormal_edge = 1;
629 else if (nonlocal_goto_handler_labels && region >= 0)
630 /* If there is a nonlocal goto label and the specified
631 region number isn't -1, we have an edge. (0 means
632 no throw, but might have a nonlocal goto). */
633 call_had_abnormal_edge = 1;
638 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
640 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
644 /* The rest of the compiler works a bit smoother when we don't have to
645 check for the edge case of do-nothing functions with no basic blocks. */
648 emit_insn (gen_rtx_USE (VOIDmode, const0_rtx));
655 /* Scan a list of insns for labels referred to other than by jumps.
656 This is used to scan the alternatives of a call placeholder. */
658 find_label_refs (f, lvl)
664 for (insn = f; insn; insn = NEXT_INSN (insn))
665 if (INSN_P (insn) && GET_CODE (insn) != JUMP_INSN)
669 /* Make a list of all labels referred to other than by jumps
670 (which just don't have the REG_LABEL notes).
672 Make a special exception for labels followed by an ADDR*VEC,
673 as this would be a part of the tablejump setup code.
675 Make a special exception for the eh_return_stub_label, which
676 we know isn't part of any otherwise visible control flow.
678 Make a special exception to registers loaded with label
679 values just before jump insns that use them. */
681 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
682 if (REG_NOTE_KIND (note) == REG_LABEL)
684 rtx lab = XEXP (note, 0), next;
686 if (lab == eh_return_stub_label)
688 else if ((next = next_nonnote_insn (lab)) != NULL
689 && GET_CODE (next) == JUMP_INSN
690 && (GET_CODE (PATTERN (next)) == ADDR_VEC
691 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
693 else if (GET_CODE (lab) == NOTE)
695 else if (GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
696 && find_reg_note (NEXT_INSN (insn), REG_LABEL, lab))
699 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
706 /* Assume that someone emitted code with control flow instructions to the
707 basic block. Update the data structure. */
709 find_sub_basic_blocks (bb)
712 rtx first_insn = bb->head, insn;
714 edge succ_list = bb->succ;
715 rtx jump_insn = NULL_RTX;
719 basic_block first_bb = bb, last_bb;
722 if (GET_CODE (first_insn) == LABEL_REF)
723 first_insn = NEXT_INSN (first_insn);
724 first_insn = NEXT_INSN (first_insn);
728 /* Scan insn chain and try to find new basic block boundaries. */
731 enum rtx_code code = GET_CODE (insn);
735 /* We need some special care for those expressions. */
736 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
737 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
746 /* On code label, split current basic block. */
748 falltru = split_block (bb, PREV_INSN (insn));
753 remove_edge (falltru);
757 if (LABEL_ALTERNATE_NAME (insn))
758 make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0);
761 /* In case we've previously split insn on the JUMP_INSN, move the
762 block header to proper place. */
765 falltru = split_block (bb, PREV_INSN (insn));
775 insn = NEXT_INSN (insn);
777 /* Last basic block must end in the original BB end. */
781 /* Wire in the original edges for last basic block. */
784 bb->succ = succ_list;
786 succ_list->src = bb, succ_list = succ_list->succ_next;
789 bb->succ = succ_list;
791 /* Now re-scan and wire in all edges. This expect simple (conditional)
792 jumps at the end of each new basic blocks. */
794 for (i = first_bb->index; i < last_bb->index; i++)
796 bb = BASIC_BLOCK (i);
797 if (GET_CODE (bb->end) == JUMP_INSN)
799 mark_jump_label (PATTERN (bb->end), bb->end, 0, 0);
800 make_label_edge (NULL, bb, JUMP_LABEL (bb->end), 0);
802 insn = NEXT_INSN (insn);
806 /* Find all basic blocks of the function whose first insn is F.
808 Collect and return a list of labels whose addresses are taken. This
809 will be used in make_edges for use with computed gotos. */
812 find_basic_blocks_1 (f)
815 register rtx insn, next;
817 rtx bb_note = NULL_RTX;
818 rtx eh_list = NULL_RTX;
824 /* We process the instructions in a slightly different way than we did
825 previously. This is so that we see a NOTE_BASIC_BLOCK after we have
826 closed out the previous block, so that it gets attached at the proper
827 place. Since this form should be equivalent to the previous,
828 count_basic_blocks continues to use the old form as a check. */
830 for (insn = f; insn; insn = next)
832 enum rtx_code code = GET_CODE (insn);
834 next = NEXT_INSN (insn);
840 int kind = NOTE_LINE_NUMBER (insn);
842 /* Keep a LIFO list of the currently active exception notes. */
843 if (kind == NOTE_INSN_EH_REGION_BEG)
844 eh_list = alloc_INSN_LIST (insn, eh_list);
845 else if (kind == NOTE_INSN_EH_REGION_END)
849 eh_list = XEXP (eh_list, 1);
850 free_INSN_LIST_node (t);
853 /* Look for basic block notes with which to keep the
854 basic_block_info pointers stable. Unthread the note now;
855 we'll put it back at the right place in create_basic_block.
856 Or not at all if we've already found a note in this block. */
857 else if (kind == NOTE_INSN_BASIC_BLOCK)
859 if (bb_note == NULL_RTX)
862 next = flow_delete_insn (insn);
868 /* A basic block starts at a label. If we've closed one off due
869 to a barrier or some such, no need to do it again. */
870 if (head != NULL_RTX)
872 /* While we now have edge lists with which other portions of
873 the compiler might determine a call ending a basic block
874 does not imply an abnormal edge, it will be a bit before
875 everything can be updated. So continue to emit a noop at
876 the end of such a block. */
877 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
879 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
880 end = emit_insn_after (nop, end);
883 create_basic_block (i++, head, end, bb_note);
891 /* A basic block ends at a jump. */
892 if (head == NULL_RTX)
896 /* ??? Make a special check for table jumps. The way this
897 happens is truly and amazingly gross. We are about to
898 create a basic block that contains just a code label and
899 an addr*vec jump insn. Worse, an addr_diff_vec creates
900 its own natural loop.
902 Prevent this bit of brain damage, pasting things together
903 correctly in make_edges.
905 The correct solution involves emitting the table directly
906 on the tablejump instruction as a note, or JUMP_LABEL. */
908 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
909 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
917 goto new_bb_inclusive;
920 /* A basic block ends at a barrier. It may be that an unconditional
921 jump already closed the basic block -- no need to do it again. */
922 if (head == NULL_RTX)
925 /* While we now have edge lists with which other portions of the
926 compiler might determine a call ending a basic block does not
927 imply an abnormal edge, it will be a bit before everything can
928 be updated. So continue to emit a noop at the end of such a
930 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
932 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
933 end = emit_insn_after (nop, end);
935 goto new_bb_exclusive;
939 /* Record whether this call created an edge. */
940 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
941 int region = (note ? INTVAL (XEXP (note, 0)) : 1);
942 int call_has_abnormal_edge = 0;
944 if (GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
946 /* Scan each of the alternatives for label refs. */
947 lvl = find_label_refs (XEXP (PATTERN (insn), 0), lvl);
948 lvl = find_label_refs (XEXP (PATTERN (insn), 1), lvl);
949 lvl = find_label_refs (XEXP (PATTERN (insn), 2), lvl);
950 /* Record its tail recursion label, if any. */
951 if (XEXP (PATTERN (insn), 3) != NULL_RTX)
952 trll = alloc_EXPR_LIST (0, XEXP (PATTERN (insn), 3), trll);
955 /* If there is an EH region or rethrow, we have an edge. */
956 if ((eh_list && region > 0)
957 || find_reg_note (insn, REG_EH_RETHROW, NULL_RTX))
958 call_has_abnormal_edge = 1;
959 else if (nonlocal_goto_handler_labels && region >= 0)
960 /* If there is a nonlocal goto label and the specified
961 region number isn't -1, we have an edge. (0 means
962 no throw, but might have a nonlocal goto). */
963 call_has_abnormal_edge = 1;
965 /* A basic block ends at a call that can either throw or
966 do a non-local goto. */
967 if (call_has_abnormal_edge)
970 if (head == NULL_RTX)
975 create_basic_block (i++, head, end, bb_note);
976 head = end = NULL_RTX;
984 if (GET_RTX_CLASS (code) == 'i')
986 if (head == NULL_RTX)
993 if (GET_RTX_CLASS (code) == 'i'
994 && GET_CODE (insn) != JUMP_INSN)
998 /* Make a list of all labels referred to other than by jumps.
1000 Make a special exception for labels followed by an ADDR*VEC,
1001 as this would be a part of the tablejump setup code.
1003 Make a special exception for the eh_return_stub_label, which
1004 we know isn't part of any otherwise visible control flow.
1006 Make a special exception to registers loaded with label
1007 values just before jump insns that use them. */
1009 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1010 if (REG_NOTE_KIND (note) == REG_LABEL)
1012 rtx lab = XEXP (note, 0), next;
1014 if (lab == eh_return_stub_label)
1016 else if ((next = next_nonnote_insn (lab)) != NULL
1017 && GET_CODE (next) == JUMP_INSN
1018 && (GET_CODE (PATTERN (next)) == ADDR_VEC
1019 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
1021 else if (GET_CODE (lab) == NOTE)
1023 else if (GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
1024 && find_reg_note (NEXT_INSN (insn), REG_LABEL, lab))
1027 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
1032 if (head != NULL_RTX)
1033 create_basic_block (i++, head, end, bb_note);
1035 flow_delete_insn (bb_note);
1037 if (i != n_basic_blocks)
1040 label_value_list = lvl;
1041 tail_recursion_label_list = trll;
1044 /* Tidy the CFG by deleting unreachable code and whatnot. */
1050 delete_unreachable_blocks ();
1051 move_stray_eh_region_notes ();
1052 record_active_eh_regions (f);
1053 try_merge_blocks ();
1054 mark_critical_edges ();
1056 /* Kill the data we won't maintain. */
1057 free_EXPR_LIST_list (&label_value_list);
1058 free_EXPR_LIST_list (&tail_recursion_label_list);
1061 /* Create a new basic block consisting of the instructions between
1062 HEAD and END inclusive. Reuses the note and basic block struct
1063 in BB_NOTE, if any. */
1066 create_basic_block (index, head, end, bb_note)
1068 rtx head, end, bb_note;
1073 && ! RTX_INTEGRATED_P (bb_note)
1074 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
1077 /* If we found an existing note, thread it back onto the chain. */
1081 if (GET_CODE (head) == CODE_LABEL)
1085 after = PREV_INSN (head);
1089 if (after != bb_note && NEXT_INSN (after) != bb_note)
1090 reorder_insns (bb_note, bb_note, after);
1094 /* Otherwise we must create a note and a basic block structure.
1095 Since we allow basic block structs in rtl, give the struct
1096 the same lifetime by allocating it off the function obstack
1097 rather than using malloc. */
1099 bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*bb));
1100 memset (bb, 0, sizeof (*bb));
1102 if (GET_CODE (head) == CODE_LABEL)
1103 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
1106 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
1109 NOTE_BASIC_BLOCK (bb_note) = bb;
1112 /* Always include the bb note in the block. */
1113 if (NEXT_INSN (end) == bb_note)
1119 BASIC_BLOCK (index) = bb;
1121 /* Tag the block so that we know it has been used when considering
1122 other basic block notes. */
1126 /* Records the basic block struct in BB_FOR_INSN, for every instruction
1127 indexed by INSN_UID. MAX is the size of the array. */
1130 compute_bb_for_insn (max)
1135 if (basic_block_for_insn)
1136 VARRAY_FREE (basic_block_for_insn);
1137 VARRAY_BB_INIT (basic_block_for_insn, max, "basic_block_for_insn");
1139 for (i = 0; i < n_basic_blocks; ++i)
1141 basic_block bb = BASIC_BLOCK (i);
1148 int uid = INSN_UID (insn);
1150 VARRAY_BB (basic_block_for_insn, uid) = bb;
1153 insn = NEXT_INSN (insn);
1158 /* Free the memory associated with the edge structures. */
1166 for (i = 0; i < n_basic_blocks; ++i)
1168 basic_block bb = BASIC_BLOCK (i);
1170 for (e = bb->succ; e; e = n)
1180 for (e = ENTRY_BLOCK_PTR->succ; e; e = n)
1186 ENTRY_BLOCK_PTR->succ = 0;
1187 EXIT_BLOCK_PTR->pred = 0;
1192 /* Identify the edges between basic blocks.
1194 NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks
1195 that are otherwise unreachable may be reachable with a non-local goto.
1197 BB_EH_END is an array indexed by basic block number in which we record
1198 the list of exception regions active at the end of the basic block. */
1201 make_edges (label_value_list)
1202 rtx label_value_list;
1205 eh_nesting_info *eh_nest_info = init_eh_nesting_info ();
1206 sbitmap *edge_cache = NULL;
1208 /* Assume no computed jump; revise as we create edges. */
1209 current_function_has_computed_jump = 0;
1211 /* Heavy use of computed goto in machine-generated code can lead to
1212 nearly fully-connected CFGs. In that case we spend a significant
1213 amount of time searching the edge lists for duplicates. */
1214 if (forced_labels || label_value_list)
1216 edge_cache = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
1217 sbitmap_vector_zero (edge_cache, n_basic_blocks);
1220 /* By nature of the way these get numbered, block 0 is always the entry. */
1221 make_edge (edge_cache, ENTRY_BLOCK_PTR, BASIC_BLOCK (0), EDGE_FALLTHRU);
1223 for (i = 0; i < n_basic_blocks; ++i)
1225 basic_block bb = BASIC_BLOCK (i);
1228 int force_fallthru = 0;
1230 if (GET_CODE (bb->head) == CODE_LABEL
1231 && LABEL_ALTERNATE_NAME (bb->head))
1232 make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0);
1234 /* Examine the last instruction of the block, and discover the
1235 ways we can leave the block. */
1238 code = GET_CODE (insn);
1241 if (code == JUMP_INSN)
1245 /* Recognize a non-local goto as a branch outside the
1246 current function. */
1247 if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX))
1250 /* ??? Recognize a tablejump and do the right thing. */
1251 else if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1252 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1253 && GET_CODE (tmp) == JUMP_INSN
1254 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1255 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1260 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1261 vec = XVEC (PATTERN (tmp), 0);
1263 vec = XVEC (PATTERN (tmp), 1);
1265 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1266 make_label_edge (edge_cache, bb,
1267 XEXP (RTVEC_ELT (vec, j), 0), 0);
1269 /* Some targets (eg, ARM) emit a conditional jump that also
1270 contains the out-of-range target. Scan for these and
1271 add an edge if necessary. */
1272 if ((tmp = single_set (insn)) != NULL
1273 && SET_DEST (tmp) == pc_rtx
1274 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1275 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF)
1276 make_label_edge (edge_cache, bb,
1277 XEXP (XEXP (SET_SRC (tmp), 2), 0), 0);
1279 #ifdef CASE_DROPS_THROUGH
1280 /* Silly VAXen. The ADDR_VEC is going to be in the way of
1281 us naturally detecting fallthru into the next block. */
1286 /* If this is a computed jump, then mark it as reaching
1287 everything on the label_value_list and forced_labels list. */
1288 else if (computed_jump_p (insn))
1290 current_function_has_computed_jump = 1;
1292 for (x = label_value_list; x; x = XEXP (x, 1))
1293 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1295 for (x = forced_labels; x; x = XEXP (x, 1))
1296 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1299 /* Returns create an exit out. */
1300 else if (returnjump_p (insn))
1301 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, 0);
1303 /* Otherwise, we have a plain conditional or unconditional jump. */
1306 if (! JUMP_LABEL (insn))
1308 make_label_edge (edge_cache, bb, JUMP_LABEL (insn), 0);
1312 /* If this is a sibling call insn, then this is in effect a
1313 combined call and return, and so we need an edge to the
1314 exit block. No need to worry about EH edges, since we
1315 wouldn't have created the sibling call in the first place. */
1317 if (code == CALL_INSN && SIBLING_CALL_P (insn))
1318 make_edge (edge_cache, bb, EXIT_BLOCK_PTR,
1319 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1321 /* If this is a CALL_INSN, then mark it as reaching the active EH
1322 handler for this CALL_INSN. If we're handling asynchronous
1323 exceptions then any insn can reach any of the active handlers.
1325 Also mark the CALL_INSN as reaching any nonlocal goto handler. */
1327 else if (code == CALL_INSN || flag_non_call_exceptions)
1329 /* Add any appropriate EH edges. We do this unconditionally
1330 since there may be a REG_EH_REGION or REG_EH_RETHROW note
1331 on the call, and this needn't be within an EH region. */
1332 make_eh_edge (edge_cache, eh_nest_info, bb, insn, bb->eh_end);
1334 /* If we have asynchronous exceptions, do the same for *all*
1335 exception regions active in the block. */
1336 if (flag_non_call_exceptions
1337 && bb->eh_beg != bb->eh_end)
1339 if (bb->eh_beg >= 0)
1340 make_eh_edge (edge_cache, eh_nest_info, bb,
1341 NULL_RTX, bb->eh_beg);
1343 for (x = bb->head; x != bb->end; x = NEXT_INSN (x))
1344 if (GET_CODE (x) == NOTE
1345 && (NOTE_LINE_NUMBER (x) == NOTE_INSN_EH_REGION_BEG
1346 || NOTE_LINE_NUMBER (x) == NOTE_INSN_EH_REGION_END))
1348 int region = NOTE_EH_HANDLER (x);
1349 make_eh_edge (edge_cache, eh_nest_info, bb,
1354 if (code == CALL_INSN && nonlocal_goto_handler_labels)
1356 /* ??? This could be made smarter: in some cases it's possible
1357 to tell that certain calls will not do a nonlocal goto.
1359 For example, if the nested functions that do the nonlocal
1360 gotos do not have their addresses taken, then only calls to
1361 those functions or to other nested functions that use them
1362 could possibly do nonlocal gotos. */
1363 /* We do know that a REG_EH_REGION note with a value less
1364 than 0 is guaranteed not to perform a non-local goto. */
1365 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
1366 if (!note || INTVAL (XEXP (note, 0)) >= 0)
1367 for (x = nonlocal_goto_handler_labels; x; x = XEXP (x, 1))
1368 make_label_edge (edge_cache, bb, XEXP (x, 0),
1369 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1373 /* We know something about the structure of the function __throw in
1374 libgcc2.c. It is the only function that ever contains eh_stub
1375 labels. It modifies its return address so that the last block
1376 returns to one of the eh_stub labels within it. So we have to
1377 make additional edges in the flow graph. */
1378 if (i + 1 == n_basic_blocks && eh_return_stub_label != 0)
1379 make_label_edge (edge_cache, bb, eh_return_stub_label, EDGE_EH);
1381 /* Find out if we can drop through to the next block. */
1382 insn = next_nonnote_insn (insn);
1383 if (!insn || (i + 1 == n_basic_blocks && force_fallthru))
1384 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU);
1385 else if (i + 1 < n_basic_blocks)
1387 rtx tmp = BLOCK_HEAD (i + 1);
1388 if (GET_CODE (tmp) == NOTE)
1389 tmp = next_nonnote_insn (tmp);
1390 if (force_fallthru || insn == tmp)
1391 make_edge (edge_cache, bb, BASIC_BLOCK (i + 1), EDGE_FALLTHRU);
1395 free_eh_nesting_info (eh_nest_info);
1397 sbitmap_vector_free (edge_cache);
1400 /* Create an edge between two basic blocks. FLAGS are auxiliary information
1401 about the edge that is accumulated between calls. */
1404 make_edge (edge_cache, src, dst, flags)
1405 sbitmap *edge_cache;
1406 basic_block src, dst;
1412 /* Don't bother with edge cache for ENTRY or EXIT; there aren't that
1413 many edges to them, and we didn't allocate memory for it. */
1414 use_edge_cache = (edge_cache
1415 && src != ENTRY_BLOCK_PTR
1416 && dst != EXIT_BLOCK_PTR);
1418 /* Make sure we don't add duplicate edges. */
1419 switch (use_edge_cache)
1422 /* Quick test for non-existance of the edge. */
1423 if (! TEST_BIT (edge_cache[src->index], dst->index))
1426 /* The edge exists; early exit if no work to do. */
1432 for (e = src->succ; e; e = e->succ_next)
1441 e = (edge) xcalloc (1, sizeof (*e));
1444 e->succ_next = src->succ;
1445 e->pred_next = dst->pred;
1454 SET_BIT (edge_cache[src->index], dst->index);
1457 /* Create an edge from a basic block to a label. */
1460 make_label_edge (edge_cache, src, label, flags)
1461 sbitmap *edge_cache;
1466 if (GET_CODE (label) != CODE_LABEL)
1469 /* If the label was never emitted, this insn is junk, but avoid a
1470 crash trying to refer to BLOCK_FOR_INSN (label). This can happen
1471 as a result of a syntax error and a diagnostic has already been
1474 if (INSN_UID (label) == 0)
1477 make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags);
1480 /* Create the edges generated by INSN in REGION. */
1483 make_eh_edge (edge_cache, eh_nest_info, src, insn, region)
1484 sbitmap *edge_cache;
1485 eh_nesting_info *eh_nest_info;
1490 handler_info **handler_list;
1493 is_call = (insn && GET_CODE (insn) == CALL_INSN ? EDGE_ABNORMAL_CALL : 0);
1494 num = reachable_handlers (region, eh_nest_info, insn, &handler_list);
1497 make_label_edge (edge_cache, src, handler_list[num]->handler_label,
1498 EDGE_ABNORMAL | EDGE_EH | is_call);
1502 /* EH_REGION notes appearing between basic blocks is ambiguous, and even
1503 dangerous if we intend to move basic blocks around. Move such notes
1504 into the following block. */
1507 move_stray_eh_region_notes ()
1512 if (n_basic_blocks < 2)
1515 b2 = BASIC_BLOCK (n_basic_blocks - 1);
1516 for (i = n_basic_blocks - 2; i >= 0; --i, b2 = b1)
1518 rtx insn, next, list = NULL_RTX;
1520 b1 = BASIC_BLOCK (i);
1521 for (insn = NEXT_INSN (b1->end); insn != b2->head; insn = next)
1523 next = NEXT_INSN (insn);
1524 if (GET_CODE (insn) == NOTE
1525 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG
1526 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
1528 /* Unlink from the insn chain. */
1529 NEXT_INSN (PREV_INSN (insn)) = next;
1530 PREV_INSN (next) = PREV_INSN (insn);
1533 NEXT_INSN (insn) = list;
1538 if (list == NULL_RTX)
1541 /* Find where to insert these things. */
1543 if (GET_CODE (insn) == CODE_LABEL)
1544 insn = NEXT_INSN (insn);
1548 next = NEXT_INSN (list);
1549 add_insn_after (list, insn);
1555 /* Recompute eh_beg/eh_end for each basic block. */
1558 record_active_eh_regions (f)
1561 rtx insn, eh_list = NULL_RTX;
1563 basic_block bb = BASIC_BLOCK (0);
1565 for (insn = f; insn; insn = NEXT_INSN (insn))
1567 if (bb->head == insn)
1568 bb->eh_beg = (eh_list ? NOTE_EH_HANDLER (XEXP (eh_list, 0)) : -1);
1570 if (GET_CODE (insn) == NOTE)
1572 int kind = NOTE_LINE_NUMBER (insn);
1573 if (kind == NOTE_INSN_EH_REGION_BEG)
1574 eh_list = alloc_INSN_LIST (insn, eh_list);
1575 else if (kind == NOTE_INSN_EH_REGION_END)
1577 rtx t = XEXP (eh_list, 1);
1578 free_INSN_LIST_node (eh_list);
1583 if (bb->end == insn)
1585 bb->eh_end = (eh_list ? NOTE_EH_HANDLER (XEXP (eh_list, 0)) : -1);
1587 if (i == n_basic_blocks)
1589 bb = BASIC_BLOCK (i);
1594 /* Identify critical edges and set the bits appropriately. */
1597 mark_critical_edges ()
1599 int i, n = n_basic_blocks;
1602 /* We begin with the entry block. This is not terribly important now,
1603 but could be if a front end (Fortran) implemented alternate entry
1605 bb = ENTRY_BLOCK_PTR;
1612 /* (1) Critical edges must have a source with multiple successors. */
1613 if (bb->succ && bb->succ->succ_next)
1615 for (e = bb->succ; e; e = e->succ_next)
1617 /* (2) Critical edges must have a destination with multiple
1618 predecessors. Note that we know there is at least one
1619 predecessor -- the edge we followed to get here. */
1620 if (e->dest->pred->pred_next)
1621 e->flags |= EDGE_CRITICAL;
1623 e->flags &= ~EDGE_CRITICAL;
1628 for (e = bb->succ; e; e = e->succ_next)
1629 e->flags &= ~EDGE_CRITICAL;
1634 bb = BASIC_BLOCK (i);
1638 /* Split a block BB after insn INSN creating a new fallthru edge.
1639 Return the new edge. Note that to keep other parts of the compiler happy,
1640 this function renumbers all the basic blocks so that the new
1641 one has a number one greater than the block split. */
1644 split_block (bb, insn)
1654 /* There is no point splitting the block after its end. */
1655 if (bb->end == insn)
1658 /* Create the new structures. */
1659 new_bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*new_bb));
1660 new_edge = (edge) xcalloc (1, sizeof (*new_edge));
1663 memset (new_bb, 0, sizeof (*new_bb));
1665 new_bb->head = NEXT_INSN (insn);
1666 new_bb->end = bb->end;
1669 new_bb->succ = bb->succ;
1670 bb->succ = new_edge;
1671 new_bb->pred = new_edge;
1672 new_bb->count = bb->count;
1673 new_bb->loop_depth = bb->loop_depth;
1676 new_edge->dest = new_bb;
1677 new_edge->flags = EDGE_FALLTHRU;
1678 new_edge->probability = REG_BR_PROB_BASE;
1679 new_edge->count = bb->count;
1681 /* Redirect the src of the successor edges of bb to point to new_bb. */
1682 for (e = new_bb->succ; e; e = e->succ_next)
1685 /* Place the new block just after the block being split. */
1686 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
1688 /* Some parts of the compiler expect blocks to be number in
1689 sequential order so insert the new block immediately after the
1690 block being split.. */
1692 for (i = n_basic_blocks - 1; i > j + 1; --i)
1694 basic_block tmp = BASIC_BLOCK (i - 1);
1695 BASIC_BLOCK (i) = tmp;
1699 BASIC_BLOCK (i) = new_bb;
1702 if (GET_CODE (new_bb->head) == CODE_LABEL)
1704 /* Create the basic block note. */
1705 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK,
1707 NOTE_BASIC_BLOCK (bb_note) = new_bb;
1711 /* Create the basic block note. */
1712 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
1714 NOTE_BASIC_BLOCK (bb_note) = new_bb;
1715 new_bb->head = bb_note;
1718 update_bb_for_insn (new_bb);
1720 if (bb->global_live_at_start)
1722 new_bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1723 new_bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1724 COPY_REG_SET (new_bb->global_live_at_end, bb->global_live_at_end);
1726 /* We now have to calculate which registers are live at the end
1727 of the split basic block and at the start of the new basic
1728 block. Start with those registers that are known to be live
1729 at the end of the original basic block and get
1730 propagate_block to determine which registers are live. */
1731 COPY_REG_SET (new_bb->global_live_at_start, bb->global_live_at_end);
1732 propagate_block (new_bb, new_bb->global_live_at_start, NULL, NULL, 0);
1733 COPY_REG_SET (bb->global_live_at_end,
1734 new_bb->global_live_at_start);
1741 /* Split a (typically critical) edge. Return the new block.
1742 Abort on abnormal edges.
1744 ??? The code generally expects to be called on critical edges.
1745 The case of a block ending in an unconditional jump to a
1746 block with multiple predecessors is not handled optimally. */
1749 split_edge (edge_in)
1752 basic_block old_pred, bb, old_succ;
1757 /* Abnormal edges cannot be split. */
1758 if ((edge_in->flags & EDGE_ABNORMAL) != 0)
1761 old_pred = edge_in->src;
1762 old_succ = edge_in->dest;
1764 /* Remove the existing edge from the destination's pred list. */
1767 for (pp = &old_succ->pred; *pp != edge_in; pp = &(*pp)->pred_next)
1769 *pp = edge_in->pred_next;
1770 edge_in->pred_next = NULL;
1773 /* Create the new structures. */
1774 bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*bb));
1775 edge_out = (edge) xcalloc (1, sizeof (*edge_out));
1778 memset (bb, 0, sizeof (*bb));
1780 /* ??? This info is likely going to be out of date very soon. */
1781 if (old_succ->global_live_at_start)
1783 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1784 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1785 COPY_REG_SET (bb->global_live_at_start, old_succ->global_live_at_start);
1786 COPY_REG_SET (bb->global_live_at_end, old_succ->global_live_at_start);
1791 bb->succ = edge_out;
1792 bb->count = edge_in->count;
1795 edge_in->flags &= ~EDGE_CRITICAL;
1797 edge_out->pred_next = old_succ->pred;
1798 edge_out->succ_next = NULL;
1800 edge_out->dest = old_succ;
1801 edge_out->flags = EDGE_FALLTHRU;
1802 edge_out->probability = REG_BR_PROB_BASE;
1803 edge_out->count = edge_in->count;
1805 old_succ->pred = edge_out;
1807 /* Tricky case -- if there existed a fallthru into the successor
1808 (and we're not it) we must add a new unconditional jump around
1809 the new block we're actually interested in.
1811 Further, if that edge is critical, this means a second new basic
1812 block must be created to hold it. In order to simplify correct
1813 insn placement, do this before we touch the existing basic block
1814 ordering for the block we were really wanting. */
1815 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1818 for (e = edge_out->pred_next; e; e = e->pred_next)
1819 if (e->flags & EDGE_FALLTHRU)
1824 basic_block jump_block;
1827 if ((e->flags & EDGE_CRITICAL) == 0
1828 && e->src != ENTRY_BLOCK_PTR)
1830 /* Non critical -- we can simply add a jump to the end
1831 of the existing predecessor. */
1832 jump_block = e->src;
1836 /* We need a new block to hold the jump. The simplest
1837 way to do the bulk of the work here is to recursively
1839 jump_block = split_edge (e);
1840 e = jump_block->succ;
1843 /* Now add the jump insn ... */
1844 pos = emit_jump_insn_after (gen_jump (old_succ->head),
1846 jump_block->end = pos;
1847 if (basic_block_for_insn)
1848 set_block_for_insn (pos, jump_block);
1849 emit_barrier_after (pos);
1851 /* ... let jump know that label is in use, ... */
1852 JUMP_LABEL (pos) = old_succ->head;
1853 ++LABEL_NUSES (old_succ->head);
1855 /* ... and clear fallthru on the outgoing edge. */
1856 e->flags &= ~EDGE_FALLTHRU;
1858 /* Continue splitting the interesting edge. */
1862 /* Place the new block just in front of the successor. */
1863 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
1864 if (old_succ == EXIT_BLOCK_PTR)
1865 j = n_basic_blocks - 1;
1867 j = old_succ->index;
1868 for (i = n_basic_blocks - 1; i > j; --i)
1870 basic_block tmp = BASIC_BLOCK (i - 1);
1871 BASIC_BLOCK (i) = tmp;
1874 BASIC_BLOCK (i) = bb;
1877 /* Create the basic block note.
1879 Where we place the note can have a noticable impact on the generated
1880 code. Consider this cfg:
1890 If we need to insert an insn on the edge from block 0 to block 1,
1891 we want to ensure the instructions we insert are outside of any
1892 loop notes that physically sit between block 0 and block 1. Otherwise
1893 we confuse the loop optimizer into thinking the loop is a phony. */
1894 if (old_succ != EXIT_BLOCK_PTR
1895 && PREV_INSN (old_succ->head)
1896 && GET_CODE (PREV_INSN (old_succ->head)) == NOTE
1897 && NOTE_LINE_NUMBER (PREV_INSN (old_succ->head)) == NOTE_INSN_LOOP_BEG)
1898 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
1899 PREV_INSN (old_succ->head));
1900 else if (old_succ != EXIT_BLOCK_PTR)
1901 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, old_succ->head);
1903 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
1904 NOTE_BASIC_BLOCK (bb_note) = bb;
1905 bb->head = bb->end = bb_note;
1907 /* Not quite simple -- for non-fallthru edges, we must adjust the
1908 predecessor's jump instruction to target our new block. */
1909 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1911 rtx tmp, insn = old_pred->end;
1912 rtx old_label = old_succ->head;
1913 rtx new_label = gen_label_rtx ();
1915 if (GET_CODE (insn) != JUMP_INSN)
1918 /* ??? Recognize a tablejump and adjust all matching cases. */
1919 if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1920 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1921 && GET_CODE (tmp) == JUMP_INSN
1922 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1923 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1928 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1929 vec = XVEC (PATTERN (tmp), 0);
1931 vec = XVEC (PATTERN (tmp), 1);
1933 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1934 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
1936 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (VOIDmode, new_label);
1937 --LABEL_NUSES (old_label);
1938 ++LABEL_NUSES (new_label);
1941 /* Handle casesi dispatch insns */
1942 if ((tmp = single_set (insn)) != NULL
1943 && SET_DEST (tmp) == pc_rtx
1944 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1945 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
1946 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
1948 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (VOIDmode,
1950 --LABEL_NUSES (old_label);
1951 ++LABEL_NUSES (new_label);
1956 /* This would have indicated an abnormal edge. */
1957 if (computed_jump_p (insn))
1960 /* A return instruction can't be redirected. */
1961 if (returnjump_p (insn))
1964 /* If the insn doesn't go where we think, we're confused. */
1965 if (JUMP_LABEL (insn) != old_label)
1968 redirect_jump (insn, new_label, 0);
1971 emit_label_before (new_label, bb_note);
1972 bb->head = new_label;
1978 /* Queue instructions for insertion on an edge between two basic blocks.
1979 The new instructions and basic blocks (if any) will not appear in the
1980 CFG until commit_edge_insertions is called. */
1983 insert_insn_on_edge (pattern, e)
1987 /* We cannot insert instructions on an abnormal critical edge.
1988 It will be easier to find the culprit if we die now. */
1989 if ((e->flags & (EDGE_ABNORMAL|EDGE_CRITICAL))
1990 == (EDGE_ABNORMAL|EDGE_CRITICAL))
1993 if (e->insns == NULL_RTX)
1996 push_to_sequence (e->insns);
1998 emit_insn (pattern);
2000 e->insns = get_insns ();
2004 /* Update the CFG for the instructions queued on edge E. */
2007 commit_one_edge_insertion (e)
2010 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
2013 /* Pull the insns off the edge now since the edge might go away. */
2015 e->insns = NULL_RTX;
2017 /* Figure out where to put these things. If the destination has
2018 one predecessor, insert there. Except for the exit block. */
2019 if (e->dest->pred->pred_next == NULL
2020 && e->dest != EXIT_BLOCK_PTR)
2024 /* Get the location correct wrt a code label, and "nice" wrt
2025 a basic block note, and before everything else. */
2027 if (GET_CODE (tmp) == CODE_LABEL)
2028 tmp = NEXT_INSN (tmp);
2029 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
2030 tmp = NEXT_INSN (tmp);
2031 if (tmp == bb->head)
2034 after = PREV_INSN (tmp);
2037 /* If the source has one successor and the edge is not abnormal,
2038 insert there. Except for the entry block. */
2039 else if ((e->flags & EDGE_ABNORMAL) == 0
2040 && e->src->succ->succ_next == NULL
2041 && e->src != ENTRY_BLOCK_PTR)
2044 /* It is possible to have a non-simple jump here. Consider a target
2045 where some forms of unconditional jumps clobber a register. This
2046 happens on the fr30 for example.
2048 We know this block has a single successor, so we can just emit
2049 the queued insns before the jump. */
2050 if (GET_CODE (bb->end) == JUMP_INSN)
2056 /* We'd better be fallthru, or we've lost track of what's what. */
2057 if ((e->flags & EDGE_FALLTHRU) == 0)
2064 /* Otherwise we must split the edge. */
2067 bb = split_edge (e);
2071 /* Now that we've found the spot, do the insertion. */
2073 /* Set the new block number for these insns, if structure is allocated. */
2074 if (basic_block_for_insn)
2077 for (i = insns; i != NULL_RTX; i = NEXT_INSN (i))
2078 set_block_for_insn (i, bb);
2083 emit_insns_before (insns, before);
2084 if (before == bb->head)
2087 last = prev_nonnote_insn (before);
2091 last = emit_insns_after (insns, after);
2092 if (after == bb->end)
2096 if (returnjump_p (last))
2098 /* ??? Remove all outgoing edges from BB and add one for EXIT.
2099 This is not currently a problem because this only happens
2100 for the (single) epilogue, which already has a fallthru edge
2104 if (e->dest != EXIT_BLOCK_PTR
2105 || e->succ_next != NULL
2106 || (e->flags & EDGE_FALLTHRU) == 0)
2108 e->flags &= ~EDGE_FALLTHRU;
2110 emit_barrier_after (last);
2114 flow_delete_insn (before);
2116 else if (GET_CODE (last) == JUMP_INSN)
2118 find_sub_basic_blocks (bb);
2121 /* Update the CFG for all queued instructions. */
2124 commit_edge_insertions ()
2129 #ifdef ENABLE_CHECKING
2130 verify_flow_info ();
2134 bb = ENTRY_BLOCK_PTR;
2139 for (e = bb->succ; e; e = next)
2141 next = e->succ_next;
2143 commit_one_edge_insertion (e);
2146 if (++i >= n_basic_blocks)
2148 bb = BASIC_BLOCK (i);
2152 /* Add fake edges to the function exit for any non constant calls in
2153 the bitmap of blocks specified by BLOCKS or to the whole CFG if
2154 BLOCKS is zero. Return the nuber of blocks that were split. */
2157 flow_call_edges_add (blocks)
2161 int blocks_split = 0;
2165 /* Map bb indicies into basic block pointers since split_block
2166 will renumber the basic blocks. */
2168 bbs = xmalloc (n_basic_blocks * sizeof (*bbs));
2172 for (i = 0; i < n_basic_blocks; i++)
2173 bbs[bb_num++] = BASIC_BLOCK (i);
2177 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
2179 bbs[bb_num++] = BASIC_BLOCK (i);
2184 /* Now add fake edges to the function exit for any non constant
2185 calls since there is no way that we can determine if they will
2188 for (i = 0; i < bb_num; i++)
2190 basic_block bb = bbs[i];
2194 for (insn = bb->end; ; insn = prev_insn)
2196 prev_insn = PREV_INSN (insn);
2197 if (GET_CODE (insn) == CALL_INSN && ! CONST_CALL_P (insn))
2201 /* Note that the following may create a new basic block
2202 and renumber the existing basic blocks. */
2203 e = split_block (bb, insn);
2207 make_edge (NULL, bb, EXIT_BLOCK_PTR, EDGE_FAKE);
2209 if (insn == bb->head)
2215 verify_flow_info ();
2218 return blocks_split;
2221 /* Delete all unreachable basic blocks. */
2224 delete_unreachable_blocks ()
2226 basic_block *worklist, *tos;
2227 int deleted_handler;
2232 tos = worklist = (basic_block *) xmalloc (sizeof (basic_block) * n);
2234 /* Use basic_block->aux as a marker. Clear them all. */
2236 for (i = 0; i < n; ++i)
2237 BASIC_BLOCK (i)->aux = NULL;
2239 /* Add our starting points to the worklist. Almost always there will
2240 be only one. It isn't inconcievable that we might one day directly
2241 support Fortran alternate entry points. */
2243 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
2247 /* Mark the block with a handy non-null value. */
2251 /* Iterate: find everything reachable from what we've already seen. */
2253 while (tos != worklist)
2255 basic_block b = *--tos;
2257 for (e = b->succ; e; e = e->succ_next)
2265 /* Delete all unreachable basic blocks. Count down so that we don't
2266 interfere with the block renumbering that happens in flow_delete_block. */
2268 deleted_handler = 0;
2270 for (i = n - 1; i >= 0; --i)
2272 basic_block b = BASIC_BLOCK (i);
2275 /* This block was found. Tidy up the mark. */
2278 deleted_handler |= flow_delete_block (b);
2281 tidy_fallthru_edges ();
2283 /* If we deleted an exception handler, we may have EH region begin/end
2284 blocks to remove as well. */
2285 if (deleted_handler)
2286 delete_eh_regions ();
2291 /* Find EH regions for which there is no longer a handler, and delete them. */
2294 delete_eh_regions ()
2298 update_rethrow_references ();
2300 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
2301 if (GET_CODE (insn) == NOTE)
2303 if ((NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
2304 || (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
2306 int num = NOTE_EH_HANDLER (insn);
2307 /* A NULL handler indicates a region is no longer needed,
2308 as long as its rethrow label isn't used. */
2309 if (get_first_handler (num) == NULL && ! rethrow_used (num))
2311 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
2312 NOTE_SOURCE_FILE (insn) = 0;
2318 /* Return true if NOTE is not one of the ones that must be kept paired,
2319 so that we may simply delete them. */
2322 can_delete_note_p (note)
2325 return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED
2326 || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK);
2329 /* Unlink a chain of insns between START and FINISH, leaving notes
2330 that must be paired. */
2333 flow_delete_insn_chain (start, finish)
2336 /* Unchain the insns one by one. It would be quicker to delete all
2337 of these with a single unchaining, rather than one at a time, but
2338 we need to keep the NOTE's. */
2344 next = NEXT_INSN (start);
2345 if (GET_CODE (start) == NOTE && !can_delete_note_p (start))
2347 else if (GET_CODE (start) == CODE_LABEL
2348 && ! can_delete_label_p (start))
2350 const char *name = LABEL_NAME (start);
2351 PUT_CODE (start, NOTE);
2352 NOTE_LINE_NUMBER (start) = NOTE_INSN_DELETED_LABEL;
2353 NOTE_SOURCE_FILE (start) = name;
2356 next = flow_delete_insn (start);
2358 if (start == finish)
2364 /* Delete the insns in a (non-live) block. We physically delete every
2365 non-deleted-note insn, and update the flow graph appropriately.
2367 Return nonzero if we deleted an exception handler. */
2369 /* ??? Preserving all such notes strikes me as wrong. It would be nice
2370 to post-process the stream to remove empty blocks, loops, ranges, etc. */
2373 flow_delete_block (b)
2376 int deleted_handler = 0;
2379 /* If the head of this block is a CODE_LABEL, then it might be the
2380 label for an exception handler which can't be reached.
2382 We need to remove the label from the exception_handler_label list
2383 and remove the associated NOTE_INSN_EH_REGION_BEG and
2384 NOTE_INSN_EH_REGION_END notes. */
2388 never_reached_warning (insn);
2390 if (GET_CODE (insn) == CODE_LABEL)
2392 rtx x, *prev = &exception_handler_labels;
2394 for (x = exception_handler_labels; x; x = XEXP (x, 1))
2396 if (XEXP (x, 0) == insn)
2398 /* Found a match, splice this label out of the EH label list. */
2399 *prev = XEXP (x, 1);
2400 XEXP (x, 1) = NULL_RTX;
2401 XEXP (x, 0) = NULL_RTX;
2403 /* Remove the handler from all regions */
2404 remove_handler (insn);
2405 deleted_handler = 1;
2408 prev = &XEXP (x, 1);
2412 /* Include any jump table following the basic block. */
2414 if (GET_CODE (end) == JUMP_INSN
2415 && (tmp = JUMP_LABEL (end)) != NULL_RTX
2416 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
2417 && GET_CODE (tmp) == JUMP_INSN
2418 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
2419 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
2422 /* Include any barrier that may follow the basic block. */
2423 tmp = next_nonnote_insn (end);
2424 if (tmp && GET_CODE (tmp) == BARRIER)
2427 /* Selectively delete the entire chain. */
2428 flow_delete_insn_chain (insn, end);
2430 /* Remove the edges into and out of this block. Note that there may
2431 indeed be edges in, if we are removing an unreachable loop. */
2435 for (e = b->pred; e; e = next)
2437 for (q = &e->src->succ; *q != e; q = &(*q)->succ_next)
2440 next = e->pred_next;
2444 for (e = b->succ; e; e = next)
2446 for (q = &e->dest->pred; *q != e; q = &(*q)->pred_next)
2449 next = e->succ_next;
2458 /* Remove the basic block from the array, and compact behind it. */
2461 return deleted_handler;
2464 /* Remove block B from the basic block array and compact behind it. */
2470 int i, n = n_basic_blocks;
2472 for (i = b->index; i + 1 < n; ++i)
2474 basic_block x = BASIC_BLOCK (i + 1);
2475 BASIC_BLOCK (i) = x;
2479 basic_block_info->num_elements--;
2483 /* Delete INSN by patching it out. Return the next insn. */
2486 flow_delete_insn (insn)
2489 rtx prev = PREV_INSN (insn);
2490 rtx next = NEXT_INSN (insn);
2493 PREV_INSN (insn) = NULL_RTX;
2494 NEXT_INSN (insn) = NULL_RTX;
2495 INSN_DELETED_P (insn) = 1;
2498 NEXT_INSN (prev) = next;
2500 PREV_INSN (next) = prev;
2502 set_last_insn (prev);
2504 if (GET_CODE (insn) == CODE_LABEL)
2505 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2507 /* If deleting a jump, decrement the use count of the label. Deleting
2508 the label itself should happen in the normal course of block merging. */
2509 if (GET_CODE (insn) == JUMP_INSN
2510 && JUMP_LABEL (insn)
2511 && GET_CODE (JUMP_LABEL (insn)) == CODE_LABEL)
2512 LABEL_NUSES (JUMP_LABEL (insn))--;
2514 /* Also if deleting an insn that references a label. */
2515 else if ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX
2516 && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
2517 LABEL_NUSES (XEXP (note, 0))--;
2522 /* True if a given label can be deleted. */
2525 can_delete_label_p (label)
2530 if (LABEL_PRESERVE_P (label))
2533 for (x = forced_labels; x; x = XEXP (x, 1))
2534 if (label == XEXP (x, 0))
2536 for (x = label_value_list; x; x = XEXP (x, 1))
2537 if (label == XEXP (x, 0))
2539 for (x = exception_handler_labels; x; x = XEXP (x, 1))
2540 if (label == XEXP (x, 0))
2543 /* User declared labels must be preserved. */
2544 if (LABEL_NAME (label) != 0)
2551 tail_recursion_label_p (label)
2556 for (x = tail_recursion_label_list; x; x = XEXP (x, 1))
2557 if (label == XEXP (x, 0))
2563 /* Blocks A and B are to be merged into a single block A. The insns
2564 are already contiguous, hence `nomove'. */
2567 merge_blocks_nomove (a, b)
2571 rtx b_head, b_end, a_end;
2572 rtx del_first = NULL_RTX, del_last = NULL_RTX;
2575 /* If there was a CODE_LABEL beginning B, delete it. */
2578 if (GET_CODE (b_head) == CODE_LABEL)
2580 /* Detect basic blocks with nothing but a label. This can happen
2581 in particular at the end of a function. */
2582 if (b_head == b_end)
2584 del_first = del_last = b_head;
2585 b_head = NEXT_INSN (b_head);
2588 /* Delete the basic block note. */
2589 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
2591 if (b_head == b_end)
2596 b_head = NEXT_INSN (b_head);
2599 /* If there was a jump out of A, delete it. */
2601 if (GET_CODE (a_end) == JUMP_INSN)
2605 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
2606 if (GET_CODE (prev) != NOTE
2607 || NOTE_LINE_NUMBER (prev) == NOTE_INSN_BASIC_BLOCK
2614 /* If this was a conditional jump, we need to also delete
2615 the insn that set cc0. */
2616 if (prev && sets_cc0_p (prev))
2619 prev = prev_nonnote_insn (prev);
2628 else if (GET_CODE (NEXT_INSN (a_end)) == BARRIER)
2629 del_first = NEXT_INSN (a_end);
2631 /* Delete everything marked above as well as crap that might be
2632 hanging out between the two blocks. */
2633 flow_delete_insn_chain (del_first, del_last);
2635 /* Normally there should only be one successor of A and that is B, but
2636 partway though the merge of blocks for conditional_execution we'll
2637 be merging a TEST block with THEN and ELSE successors. Free the
2638 whole lot of them and hope the caller knows what they're doing. */
2640 remove_edge (a->succ);
2642 /* Adjust the edges out of B for the new owner. */
2643 for (e = b->succ; e; e = e->succ_next)
2647 /* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */
2648 b->pred = b->succ = NULL;
2650 /* Reassociate the insns of B with A. */
2653 if (basic_block_for_insn)
2655 BLOCK_FOR_INSN (b_head) = a;
2656 while (b_head != b_end)
2658 b_head = NEXT_INSN (b_head);
2659 BLOCK_FOR_INSN (b_head) = a;
2669 /* Blocks A and B are to be merged into a single block. A has no incoming
2670 fallthru edge, so it can be moved before B without adding or modifying
2671 any jumps (aside from the jump from A to B). */
2674 merge_blocks_move_predecessor_nojumps (a, b)
2677 rtx start, end, barrier;
2683 barrier = next_nonnote_insn (end);
2684 if (GET_CODE (barrier) != BARRIER)
2686 flow_delete_insn (barrier);
2688 /* Move block and loop notes out of the chain so that we do not
2689 disturb their order.
2691 ??? A better solution would be to squeeze out all the non-nested notes
2692 and adjust the block trees appropriately. Even better would be to have
2693 a tighter connection between block trees and rtl so that this is not
2695 start = squeeze_notes (start, end);
2697 /* Scramble the insn chain. */
2698 if (end != PREV_INSN (b->head))
2699 reorder_insns (start, end, PREV_INSN (b->head));
2703 fprintf (rtl_dump_file, "Moved block %d before %d and merged.\n",
2704 a->index, b->index);
2707 /* Swap the records for the two blocks around. Although we are deleting B,
2708 A is now where B was and we want to compact the BB array from where
2710 BASIC_BLOCK (a->index) = b;
2711 BASIC_BLOCK (b->index) = a;
2713 a->index = b->index;
2716 /* Now blocks A and B are contiguous. Merge them. */
2717 merge_blocks_nomove (a, b);
2722 /* Blocks A and B are to be merged into a single block. B has no outgoing
2723 fallthru edge, so it can be moved after A without adding or modifying
2724 any jumps (aside from the jump from A to B). */
2727 merge_blocks_move_successor_nojumps (a, b)
2730 rtx start, end, barrier;
2734 barrier = NEXT_INSN (end);
2736 /* Recognize a jump table following block B. */
2737 if (GET_CODE (barrier) == CODE_LABEL
2738 && NEXT_INSN (barrier)
2739 && GET_CODE (NEXT_INSN (barrier)) == JUMP_INSN
2740 && (GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_VEC
2741 || GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_DIFF_VEC))
2743 end = NEXT_INSN (barrier);
2744 barrier = NEXT_INSN (end);
2747 /* There had better have been a barrier there. Delete it. */
2748 if (GET_CODE (barrier) != BARRIER)
2750 flow_delete_insn (barrier);
2752 /* Move block and loop notes out of the chain so that we do not
2753 disturb their order.
2755 ??? A better solution would be to squeeze out all the non-nested notes
2756 and adjust the block trees appropriately. Even better would be to have
2757 a tighter connection between block trees and rtl so that this is not
2759 start = squeeze_notes (start, end);
2761 /* Scramble the insn chain. */
2762 reorder_insns (start, end, a->end);
2764 /* Now blocks A and B are contiguous. Merge them. */
2765 merge_blocks_nomove (a, b);
2769 fprintf (rtl_dump_file, "Moved block %d after %d and merged.\n",
2770 b->index, a->index);
2776 /* Attempt to merge basic blocks that are potentially non-adjacent.
2777 Return true iff the attempt succeeded. */
2780 merge_blocks (e, b, c)
2784 /* If C has a tail recursion label, do not merge. There is no
2785 edge recorded from the call_placeholder back to this label, as
2786 that would make optimize_sibling_and_tail_recursive_calls more
2787 complex for no gain. */
2788 if (GET_CODE (c->head) == CODE_LABEL
2789 && tail_recursion_label_p (c->head))
2792 /* If B has a fallthru edge to C, no need to move anything. */
2793 if (e->flags & EDGE_FALLTHRU)
2795 merge_blocks_nomove (b, c);
2799 fprintf (rtl_dump_file, "Merged %d and %d without moving.\n",
2800 b->index, c->index);
2809 int c_has_outgoing_fallthru;
2810 int b_has_incoming_fallthru;
2812 /* We must make sure to not munge nesting of exception regions,
2813 lexical blocks, and loop notes.
2815 The first is taken care of by requiring that the active eh
2816 region at the end of one block always matches the active eh
2817 region at the beginning of the next block.
2819 The later two are taken care of by squeezing out all the notes. */
2821 /* ??? A throw/catch edge (or any abnormal edge) should be rarely
2822 executed and we may want to treat blocks which have two out
2823 edges, one normal, one abnormal as only having one edge for
2824 block merging purposes. */
2826 for (tmp_edge = c->succ; tmp_edge; tmp_edge = tmp_edge->succ_next)
2827 if (tmp_edge->flags & EDGE_FALLTHRU)
2829 c_has_outgoing_fallthru = (tmp_edge != NULL);
2831 for (tmp_edge = b->pred; tmp_edge; tmp_edge = tmp_edge->pred_next)
2832 if (tmp_edge->flags & EDGE_FALLTHRU)
2834 b_has_incoming_fallthru = (tmp_edge != NULL);
2836 /* If B does not have an incoming fallthru, and the exception regions
2837 match, then it can be moved immediately before C without introducing
2840 C can not be the first block, so we do not have to worry about
2841 accessing a non-existent block. */
2842 d = BASIC_BLOCK (c->index - 1);
2843 if (! b_has_incoming_fallthru
2844 && d->eh_end == b->eh_beg
2845 && b->eh_end == c->eh_beg)
2846 return merge_blocks_move_predecessor_nojumps (b, c);
2848 /* Otherwise, we're going to try to move C after B. Make sure the
2849 exception regions match.
2851 If B is the last basic block, then we must not try to access the
2852 block structure for block B + 1. Luckily in that case we do not
2853 need to worry about matching exception regions. */
2854 d = (b->index + 1 < n_basic_blocks ? BASIC_BLOCK (b->index + 1) : NULL);
2855 if (b->eh_end == c->eh_beg
2856 && (d == NULL || c->eh_end == d->eh_beg))
2858 /* If C does not have an outgoing fallthru, then it can be moved
2859 immediately after B without introducing or modifying jumps. */
2860 if (! c_has_outgoing_fallthru)
2861 return merge_blocks_move_successor_nojumps (b, c);
2863 /* Otherwise, we'll need to insert an extra jump, and possibly
2864 a new block to contain it. */
2865 /* ??? Not implemented yet. */
2872 /* Top level driver for merge_blocks. */
2879 /* Attempt to merge blocks as made possible by edge removal. If a block
2880 has only one successor, and the successor has only one predecessor,
2881 they may be combined. */
2883 for (i = 0; i < n_basic_blocks;)
2885 basic_block c, b = BASIC_BLOCK (i);
2888 /* A loop because chains of blocks might be combineable. */
2889 while ((s = b->succ) != NULL
2890 && s->succ_next == NULL
2891 && (s->flags & EDGE_EH) == 0
2892 && (c = s->dest) != EXIT_BLOCK_PTR
2893 && c->pred->pred_next == NULL
2894 /* If the jump insn has side effects, we can't kill the edge. */
2895 && (GET_CODE (b->end) != JUMP_INSN
2896 || onlyjump_p (b->end))
2897 && merge_blocks (s, b, c))
2900 /* Don't get confused by the index shift caused by deleting blocks. */
2905 /* The given edge should potentially be a fallthru edge. If that is in
2906 fact true, delete the jump and barriers that are in the way. */
2909 tidy_fallthru_edge (e, b, c)
2915 /* ??? In a late-running flow pass, other folks may have deleted basic
2916 blocks by nopping out blocks, leaving multiple BARRIERs between here
2917 and the target label. They ought to be chastized and fixed.
2919 We can also wind up with a sequence of undeletable labels between
2920 one block and the next.
2922 So search through a sequence of barriers, labels, and notes for
2923 the head of block C and assert that we really do fall through. */
2925 if (next_real_insn (b->end) != next_real_insn (PREV_INSN (c->head)))
2928 /* Remove what will soon cease being the jump insn from the source block.
2929 If block B consisted only of this single jump, turn it into a deleted
2932 if (GET_CODE (q) == JUMP_INSN
2934 && (any_uncondjump_p (q)
2935 || (b->succ == e && e->succ_next == NULL)))
2938 /* If this was a conditional jump, we need to also delete
2939 the insn that set cc0. */
2940 if (any_condjump_p (q) && sets_cc0_p (PREV_INSN (q)))
2947 NOTE_LINE_NUMBER (q) = NOTE_INSN_DELETED;
2948 NOTE_SOURCE_FILE (q) = 0;
2954 /* We don't want a block to end on a line-number note since that has
2955 the potential of changing the code between -g and not -g. */
2956 while (GET_CODE (q) == NOTE && NOTE_LINE_NUMBER (q) >= 0)
2963 /* Selectively unlink the sequence. */
2964 if (q != PREV_INSN (c->head))
2965 flow_delete_insn_chain (NEXT_INSN (q), PREV_INSN (c->head));
2967 e->flags |= EDGE_FALLTHRU;
2970 /* Fix up edges that now fall through, or rather should now fall through
2971 but previously required a jump around now deleted blocks. Simplify
2972 the search by only examining blocks numerically adjacent, since this
2973 is how find_basic_blocks created them. */
2976 tidy_fallthru_edges ()
2980 for (i = 1; i < n_basic_blocks; ++i)
2982 basic_block b = BASIC_BLOCK (i - 1);
2983 basic_block c = BASIC_BLOCK (i);
2986 /* We care about simple conditional or unconditional jumps with
2989 If we had a conditional branch to the next instruction when
2990 find_basic_blocks was called, then there will only be one
2991 out edge for the block which ended with the conditional
2992 branch (since we do not create duplicate edges).
2994 Furthermore, the edge will be marked as a fallthru because we
2995 merge the flags for the duplicate edges. So we do not want to
2996 check that the edge is not a FALLTHRU edge. */
2997 if ((s = b->succ) != NULL
2998 && ! (s->flags & EDGE_COMPLEX)
2999 && s->succ_next == NULL
3001 /* If the jump insn has side effects, we can't tidy the edge. */
3002 && (GET_CODE (b->end) != JUMP_INSN
3003 || onlyjump_p (b->end)))
3004 tidy_fallthru_edge (s, b, c);
3008 /* Perform data flow analysis.
3009 F is the first insn of the function; FLAGS is a set of PROP_* flags
3010 to be used in accumulating flow info. */
3013 life_analysis (f, file, flags)
3018 #ifdef ELIMINABLE_REGS
3020 static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
3023 /* Record which registers will be eliminated. We use this in
3026 CLEAR_HARD_REG_SET (elim_reg_set);
3028 #ifdef ELIMINABLE_REGS
3029 for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
3030 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
3032 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
3036 flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC);
3038 /* The post-reload life analysis have (on a global basis) the same
3039 registers live as was computed by reload itself. elimination
3040 Otherwise offsets and such may be incorrect.
3042 Reload will make some registers as live even though they do not
3045 We don't want to create new auto-incs after reload, since they
3046 are unlikely to be useful and can cause problems with shared
3048 if (reload_completed)
3049 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
3051 /* We want alias analysis information for local dead store elimination. */
3052 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
3053 init_alias_analysis ();
3055 /* Always remove no-op moves. Do this before other processing so
3056 that we don't have to keep re-scanning them. */
3057 delete_noop_moves (f);
3059 /* Some targets can emit simpler epilogues if they know that sp was
3060 not ever modified during the function. After reload, of course,
3061 we've already emitted the epilogue so there's no sense searching. */
3062 if (! reload_completed)
3063 notice_stack_pointer_modification (f);
3065 /* Allocate and zero out data structures that will record the
3066 data from lifetime analysis. */
3067 allocate_reg_life_data ();
3068 allocate_bb_life_data ();
3070 /* Find the set of registers live on function exit. */
3071 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
3073 /* "Update" life info from zero. It'd be nice to begin the
3074 relaxation with just the exit and noreturn blocks, but that set
3075 is not immediately handy. */
3077 if (flags & PROP_REG_INFO)
3078 memset (regs_ever_live, 0, sizeof (regs_ever_live));
3079 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
3082 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
3083 end_alias_analysis ();
3086 dump_flow_info (file);
3088 free_basic_block_vars (1);
3091 /* A subroutine of verify_wide_reg, called through for_each_rtx.
3092 Search for REGNO. If found, abort if it is not wider than word_mode. */
3095 verify_wide_reg_1 (px, pregno)
3100 unsigned int regno = *(int *) pregno;
3102 if (GET_CODE (x) == REG && REGNO (x) == regno)
3104 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
3111 /* A subroutine of verify_local_live_at_start. Search through insns
3112 between HEAD and END looking for register REGNO. */
3115 verify_wide_reg (regno, head, end)
3122 && for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no))
3126 head = NEXT_INSN (head);
3129 /* We didn't find the register at all. Something's way screwy. */
3131 fprintf (rtl_dump_file, "Aborting in verify_wide_reg; reg %d\n", regno);
3132 print_rtl_and_abort ();
3135 /* A subroutine of update_life_info. Verify that there are no untoward
3136 changes in live_at_start during a local update. */
3139 verify_local_live_at_start (new_live_at_start, bb)
3140 regset new_live_at_start;
3143 if (reload_completed)
3145 /* After reload, there are no pseudos, nor subregs of multi-word
3146 registers. The regsets should exactly match. */
3147 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
3151 fprintf (rtl_dump_file,
3152 "live_at_start mismatch in bb %d, aborting\n",
3154 debug_bitmap_file (rtl_dump_file, bb->global_live_at_start);
3155 debug_bitmap_file (rtl_dump_file, new_live_at_start);
3157 print_rtl_and_abort ();
3164 /* Find the set of changed registers. */
3165 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
3167 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
3169 /* No registers should die. */
3170 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
3173 fprintf (rtl_dump_file,
3174 "Register %d died unexpectedly in block %d\n", i,
3176 print_rtl_and_abort ();
3179 /* Verify that the now-live register is wider than word_mode. */
3180 verify_wide_reg (i, bb->head, bb->end);
3185 /* Updates life information starting with the basic blocks set in BLOCKS.
3186 If BLOCKS is null, consider it to be the universal set.
3188 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
3189 we are only expecting local modifications to basic blocks. If we find
3190 extra registers live at the beginning of a block, then we either killed
3191 useful data, or we have a broken split that wants data not provided.
3192 If we find registers removed from live_at_start, that means we have
3193 a broken peephole that is killing a register it shouldn't.
3195 ??? This is not true in one situation -- when a pre-reload splitter
3196 generates subregs of a multi-word pseudo, current life analysis will
3197 lose the kill. So we _can_ have a pseudo go live. How irritating.
3199 Including PROP_REG_INFO does not properly refresh regs_ever_live
3200 unless the caller resets it to zero. */
3203 update_life_info (blocks, extent, prop_flags)
3205 enum update_life_extent extent;
3209 regset_head tmp_head;
3212 tmp = INITIALIZE_REG_SET (tmp_head);
3214 /* For a global update, we go through the relaxation process again. */
3215 if (extent != UPDATE_LIFE_LOCAL)
3217 calculate_global_regs_live (blocks, blocks,
3218 prop_flags & PROP_SCAN_DEAD_CODE);
3220 /* If asked, remove notes from the blocks we'll update. */
3221 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
3222 count_or_remove_death_notes (blocks, 1);
3227 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
3229 basic_block bb = BASIC_BLOCK (i);
3231 COPY_REG_SET (tmp, bb->global_live_at_end);
3232 propagate_block (bb, tmp, NULL, NULL, prop_flags);
3234 if (extent == UPDATE_LIFE_LOCAL)
3235 verify_local_live_at_start (tmp, bb);
3240 for (i = n_basic_blocks - 1; i >= 0; --i)
3242 basic_block bb = BASIC_BLOCK (i);
3244 COPY_REG_SET (tmp, bb->global_live_at_end);
3245 propagate_block (bb, tmp, NULL, NULL, prop_flags);
3247 if (extent == UPDATE_LIFE_LOCAL)
3248 verify_local_live_at_start (tmp, bb);
3254 if (prop_flags & PROP_REG_INFO)
3256 /* The only pseudos that are live at the beginning of the function
3257 are those that were not set anywhere in the function. local-alloc
3258 doesn't know how to handle these correctly, so mark them as not
3259 local to any one basic block. */
3260 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
3261 FIRST_PSEUDO_REGISTER, i,
3262 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
3264 /* We have a problem with any pseudoreg that lives across the setjmp.
3265 ANSI says that if a user variable does not change in value between
3266 the setjmp and the longjmp, then the longjmp preserves it. This
3267 includes longjmp from a place where the pseudo appears dead.
3268 (In principle, the value still exists if it is in scope.)
3269 If the pseudo goes in a hard reg, some other value may occupy
3270 that hard reg where this pseudo is dead, thus clobbering the pseudo.
3271 Conclusion: such a pseudo must not go in a hard reg. */
3272 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
3273 FIRST_PSEUDO_REGISTER, i,
3275 if (regno_reg_rtx[i] != 0)
3277 REG_LIVE_LENGTH (i) = -1;
3278 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
3284 /* Free the variables allocated by find_basic_blocks.
3286 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
3289 free_basic_block_vars (keep_head_end_p)
3290 int keep_head_end_p;
3292 if (basic_block_for_insn)
3294 VARRAY_FREE (basic_block_for_insn);
3295 basic_block_for_insn = NULL;
3298 if (! keep_head_end_p)
3301 VARRAY_FREE (basic_block_info);
3304 ENTRY_BLOCK_PTR->aux = NULL;
3305 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
3306 EXIT_BLOCK_PTR->aux = NULL;
3307 EXIT_BLOCK_PTR->global_live_at_start = NULL;
3311 /* Return nonzero if the destination of SET equals the source. */
3317 rtx src = SET_SRC (set);
3318 rtx dst = SET_DEST (set);
3320 if (GET_CODE (src) == SUBREG && GET_CODE (dst) == SUBREG)
3322 if (SUBREG_WORD (src) != SUBREG_WORD (dst))
3324 src = SUBREG_REG (src);
3325 dst = SUBREG_REG (dst);
3328 return (GET_CODE (src) == REG && GET_CODE (dst) == REG
3329 && REGNO (src) == REGNO (dst));
3332 /* Return nonzero if an insn consists only of SETs, each of which only sets a
3339 rtx pat = PATTERN (insn);
3341 /* Insns carrying these notes are useful later on. */
3342 if (find_reg_note (insn, REG_EQUAL, NULL_RTX))
3345 if (GET_CODE (pat) == SET && set_noop_p (pat))
3348 if (GET_CODE (pat) == PARALLEL)
3351 /* If nothing but SETs of registers to themselves,
3352 this insn can also be deleted. */
3353 for (i = 0; i < XVECLEN (pat, 0); i++)
3355 rtx tem = XVECEXP (pat, 0, i);
3357 if (GET_CODE (tem) == USE
3358 || GET_CODE (tem) == CLOBBER)
3361 if (GET_CODE (tem) != SET || ! set_noop_p (tem))
3370 /* Delete any insns that copy a register to itself. */
3373 delete_noop_moves (f)
3377 for (insn = f; insn; insn = NEXT_INSN (insn))
3379 if (GET_CODE (insn) == INSN && noop_move_p (insn))
3381 PUT_CODE (insn, NOTE);
3382 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
3383 NOTE_SOURCE_FILE (insn) = 0;
3388 /* Determine if the stack pointer is constant over the life of the function.
3389 Only useful before prologues have been emitted. */
3392 notice_stack_pointer_modification_1 (x, pat, data)
3394 rtx pat ATTRIBUTE_UNUSED;
3395 void *data ATTRIBUTE_UNUSED;
3397 if (x == stack_pointer_rtx
3398 /* The stack pointer is only modified indirectly as the result
3399 of a push until later in flow. See the comments in rtl.texi
3400 regarding Embedded Side-Effects on Addresses. */
3401 || (GET_CODE (x) == MEM
3402 && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
3403 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
3404 current_function_sp_is_unchanging = 0;
3408 notice_stack_pointer_modification (f)
3413 /* Assume that the stack pointer is unchanging if alloca hasn't
3415 current_function_sp_is_unchanging = !current_function_calls_alloca;
3416 if (! current_function_sp_is_unchanging)
3419 for (insn = f; insn; insn = NEXT_INSN (insn))
3423 /* Check if insn modifies the stack pointer. */
3424 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
3426 if (! current_function_sp_is_unchanging)
3432 /* Mark a register in SET. Hard registers in large modes get all
3433 of their component registers set as well. */
3436 mark_reg (reg, xset)
3440 regset set = (regset) xset;
3441 int regno = REGNO (reg);
3443 if (GET_MODE (reg) == BLKmode)
3446 SET_REGNO_REG_SET (set, regno);
3447 if (regno < FIRST_PSEUDO_REGISTER)
3449 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
3451 SET_REGNO_REG_SET (set, regno + n);
3455 /* Mark those regs which are needed at the end of the function as live
3456 at the end of the last basic block. */
3459 mark_regs_live_at_end (set)
3464 /* If exiting needs the right stack value, consider the stack pointer
3465 live at the end of the function. */
3466 if ((HAVE_epilogue && reload_completed)
3467 || ! EXIT_IGNORE_STACK
3468 || (! FRAME_POINTER_REQUIRED
3469 && ! current_function_calls_alloca
3470 && flag_omit_frame_pointer)
3471 || current_function_sp_is_unchanging)
3473 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
3476 /* Mark the frame pointer if needed at the end of the function. If
3477 we end up eliminating it, it will be removed from the live list
3478 of each basic block by reload. */
3480 if (! reload_completed || frame_pointer_needed)
3482 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
3483 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3484 /* If they are different, also mark the hard frame pointer as live. */
3485 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
3486 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
3490 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
3491 /* Many architectures have a GP register even without flag_pic.
3492 Assume the pic register is not in use, or will be handled by
3493 other means, if it is not fixed. */
3494 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
3495 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
3496 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
3499 /* Mark all global registers, and all registers used by the epilogue
3500 as being live at the end of the function since they may be
3501 referenced by our caller. */
3502 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3503 if (global_regs[i] || EPILOGUE_USES (i))
3504 SET_REGNO_REG_SET (set, i);
3506 /* Mark all call-saved registers that we actaully used. */
3507 if (HAVE_epilogue && reload_completed)
3509 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3510 if (regs_ever_live[i] && ! call_used_regs[i] && ! LOCAL_REGNO (i))
3511 SET_REGNO_REG_SET (set, i);
3514 /* Mark function return value. */
3515 diddle_return_value (mark_reg, set);
3518 /* Callback function for for_each_successor_phi. DATA is a regset.
3519 Sets the SRC_REGNO, the regno of the phi alternative for phi node
3520 INSN, in the regset. */
3523 set_phi_alternative_reg (insn, dest_regno, src_regno, data)
3524 rtx insn ATTRIBUTE_UNUSED;
3525 int dest_regno ATTRIBUTE_UNUSED;
3529 regset live = (regset) data;
3530 SET_REGNO_REG_SET (live, src_regno);
3534 /* Propagate global life info around the graph of basic blocks. Begin
3535 considering blocks with their corresponding bit set in BLOCKS_IN.
3536 If BLOCKS_IN is null, consider it the universal set.
3538 BLOCKS_OUT is set for every block that was changed. */
3541 calculate_global_regs_live (blocks_in, blocks_out, flags)
3542 sbitmap blocks_in, blocks_out;
3545 basic_block *queue, *qhead, *qtail, *qend;
3546 regset tmp, new_live_at_end, call_used;
3547 regset_head tmp_head, call_used_head;
3548 regset_head new_live_at_end_head;
3551 tmp = INITIALIZE_REG_SET (tmp_head);
3552 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
3553 call_used = INITIALIZE_REG_SET (call_used_head);
3555 /* Inconveniently, this is only redily available in hard reg set form. */
3556 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
3557 if (call_used_regs[i])
3558 SET_REGNO_REG_SET (call_used, i);
3560 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
3561 because the `head == tail' style test for an empty queue doesn't
3562 work with a full queue. */
3563 queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
3565 qhead = qend = queue + n_basic_blocks + 2;
3567 /* Queue the blocks set in the initial mask. Do this in reverse block
3568 number order so that we are more likely for the first round to do
3569 useful work. We use AUX non-null to flag that the block is queued. */
3572 /* Clear out the garbage that might be hanging out in bb->aux. */
3573 for (i = n_basic_blocks - 1; i >= 0; --i)
3574 BASIC_BLOCK (i)->aux = NULL;
3576 EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
3578 basic_block bb = BASIC_BLOCK (i);
3585 for (i = 0; i < n_basic_blocks; ++i)
3587 basic_block bb = BASIC_BLOCK (i);
3594 sbitmap_zero (blocks_out);
3596 while (qhead != qtail)
3598 int rescan, changed;
3607 /* Begin by propogating live_at_start from the successor blocks. */
3608 CLEAR_REG_SET (new_live_at_end);
3609 for (e = bb->succ; e; e = e->succ_next)
3611 basic_block sb = e->dest;
3613 /* Call-clobbered registers die across exception and call edges. */
3614 /* ??? Abnormal call edges ignored for the moment, as this gets
3615 confused by sibling call edges, which crashes reg-stack. */
3616 if (e->flags & EDGE_EH)
3618 bitmap_operation (tmp, sb->global_live_at_start,
3619 call_used, BITMAP_AND_COMPL);
3620 IOR_REG_SET (new_live_at_end, tmp);
3623 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
3626 /* The all-important stack pointer must always be live. */
3627 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
3629 /* Before reload, there are a few registers that must be forced
3630 live everywhere -- which might not already be the case for
3631 blocks within infinite loops. */
3632 if (! reload_completed)
3634 /* Any reference to any pseudo before reload is a potential
3635 reference of the frame pointer. */
3636 SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
3638 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3639 /* Pseudos with argument area equivalences may require
3640 reloading via the argument pointer. */
3641 if (fixed_regs[ARG_POINTER_REGNUM])
3642 SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
3645 /* Any constant, or pseudo with constant equivalences, may
3646 require reloading from memory using the pic register. */
3647 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
3648 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
3649 SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
3652 /* Regs used in phi nodes are not included in
3653 global_live_at_start, since they are live only along a
3654 particular edge. Set those regs that are live because of a
3655 phi node alternative corresponding to this particular block. */
3657 for_each_successor_phi (bb, &set_phi_alternative_reg,
3660 if (bb == ENTRY_BLOCK_PTR)
3662 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3666 /* On our first pass through this block, we'll go ahead and continue.
3667 Recognize first pass by local_set NULL. On subsequent passes, we
3668 get to skip out early if live_at_end wouldn't have changed. */
3670 if (bb->local_set == NULL)
3672 bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3673 bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3678 /* If any bits were removed from live_at_end, we'll have to
3679 rescan the block. This wouldn't be necessary if we had
3680 precalculated local_live, however with PROP_SCAN_DEAD_CODE
3681 local_live is really dependent on live_at_end. */
3682 CLEAR_REG_SET (tmp);
3683 rescan = bitmap_operation (tmp, bb->global_live_at_end,
3684 new_live_at_end, BITMAP_AND_COMPL);
3688 /* If any of the registers in the new live_at_end set are
3689 conditionally set in this basic block, we must rescan.
3690 This is because conditional lifetimes at the end of the
3691 block do not just take the live_at_end set into account,
3692 but also the liveness at the start of each successor
3693 block. We can miss changes in those sets if we only
3694 compare the new live_at_end against the previous one. */
3695 CLEAR_REG_SET (tmp);
3696 rescan = bitmap_operation (tmp, new_live_at_end,
3697 bb->cond_local_set, BITMAP_AND);
3702 /* Find the set of changed bits. Take this opportunity
3703 to notice that this set is empty and early out. */
3704 CLEAR_REG_SET (tmp);
3705 changed = bitmap_operation (tmp, bb->global_live_at_end,
3706 new_live_at_end, BITMAP_XOR);
3710 /* If any of the changed bits overlap with local_set,
3711 we'll have to rescan the block. Detect overlap by
3712 the AND with ~local_set turning off bits. */
3713 rescan = bitmap_operation (tmp, tmp, bb->local_set,
3718 /* Let our caller know that BB changed enough to require its
3719 death notes updated. */
3721 SET_BIT (blocks_out, bb->index);
3725 /* Add to live_at_start the set of all registers in
3726 new_live_at_end that aren't in the old live_at_end. */
3728 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
3730 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3732 changed = bitmap_operation (bb->global_live_at_start,
3733 bb->global_live_at_start,
3740 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3742 /* Rescan the block insn by insn to turn (a copy of) live_at_end
3743 into live_at_start. */
3744 propagate_block (bb, new_live_at_end, bb->local_set,
3745 bb->cond_local_set, flags);
3747 /* If live_at start didn't change, no need to go farther. */
3748 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
3751 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
3754 /* Queue all predecessors of BB so that we may re-examine
3755 their live_at_end. */
3756 for (e = bb->pred; e; e = e->pred_next)
3758 basic_block pb = e->src;
3759 if (pb->aux == NULL)
3770 FREE_REG_SET (new_live_at_end);
3771 FREE_REG_SET (call_used);
3775 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
3777 basic_block bb = BASIC_BLOCK (i);
3778 FREE_REG_SET (bb->local_set);
3779 FREE_REG_SET (bb->cond_local_set);
3784 for (i = n_basic_blocks - 1; i >= 0; --i)
3786 basic_block bb = BASIC_BLOCK (i);
3787 FREE_REG_SET (bb->local_set);
3788 FREE_REG_SET (bb->cond_local_set);
3795 /* Subroutines of life analysis. */
3797 /* Allocate the permanent data structures that represent the results
3798 of life analysis. Not static since used also for stupid life analysis. */
3801 allocate_bb_life_data ()
3805 for (i = 0; i < n_basic_blocks; i++)
3807 basic_block bb = BASIC_BLOCK (i);
3809 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3810 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3813 ENTRY_BLOCK_PTR->global_live_at_end
3814 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3815 EXIT_BLOCK_PTR->global_live_at_start
3816 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3818 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3822 allocate_reg_life_data ()
3826 max_regno = max_reg_num ();
3828 /* Recalculate the register space, in case it has grown. Old style
3829 vector oriented regsets would set regset_{size,bytes} here also. */
3830 allocate_reg_info (max_regno, FALSE, FALSE);
3832 /* Reset all the data we'll collect in propagate_block and its
3834 for (i = 0; i < max_regno; i++)
3838 REG_N_DEATHS (i) = 0;
3839 REG_N_CALLS_CROSSED (i) = 0;
3840 REG_LIVE_LENGTH (i) = 0;
3841 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
3845 /* Delete dead instructions for propagate_block. */
3848 propagate_block_delete_insn (bb, insn)
3852 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
3854 /* If the insn referred to a label, and that label was attached to
3855 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
3856 pretty much mandatory to delete it, because the ADDR_VEC may be
3857 referencing labels that no longer exist. */
3861 rtx label = XEXP (inote, 0);
3864 if (LABEL_NUSES (label) == 1
3865 && (next = next_nonnote_insn (label)) != NULL
3866 && GET_CODE (next) == JUMP_INSN
3867 && (GET_CODE (PATTERN (next)) == ADDR_VEC
3868 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
3870 rtx pat = PATTERN (next);
3871 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
3872 int len = XVECLEN (pat, diff_vec_p);
3875 for (i = 0; i < len; i++)
3876 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
3878 flow_delete_insn (next);
3882 if (bb->end == insn)
3883 bb->end = PREV_INSN (insn);
3884 flow_delete_insn (insn);
3887 /* Delete dead libcalls for propagate_block. Return the insn
3888 before the libcall. */
3891 propagate_block_delete_libcall (bb, insn, note)
3895 rtx first = XEXP (note, 0);
3896 rtx before = PREV_INSN (first);
3898 if (insn == bb->end)
3901 flow_delete_insn_chain (first, insn);
3905 /* Update the life-status of regs for one insn. Return the previous insn. */
3908 propagate_one_insn (pbi, insn)
3909 struct propagate_block_info *pbi;
3912 rtx prev = PREV_INSN (insn);
3913 int flags = pbi->flags;
3914 int insn_is_dead = 0;
3915 int libcall_is_dead = 0;
3919 if (! INSN_P (insn))
3922 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
3923 if (flags & PROP_SCAN_DEAD_CODE)
3925 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
3926 libcall_is_dead = (insn_is_dead && note != 0
3927 && libcall_dead_p (pbi, note, insn));
3930 /* If an instruction consists of just dead store(s) on final pass,
3932 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
3934 /* If we're trying to delete a prologue or epilogue instruction
3935 that isn't flagged as possibly being dead, something is wrong.
3936 But if we are keeping the stack pointer depressed, we might well
3937 be deleting insns that are used to compute the amount to update
3938 it by, so they are fine. */
3939 if (reload_completed
3940 && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
3941 && (TYPE_RETURNS_STACK_DEPRESSED
3942 (TREE_TYPE (current_function_decl))))
3943 && (((HAVE_epilogue || HAVE_prologue)
3944 && prologue_epilogue_contains (insn))
3945 || (HAVE_sibcall_epilogue
3946 && sibcall_epilogue_contains (insn)))
3947 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
3950 /* Record sets. Do this even for dead instructions, since they
3951 would have killed the values if they hadn't been deleted. */
3952 mark_set_regs (pbi, PATTERN (insn), insn);
3954 /* CC0 is now known to be dead. Either this insn used it,
3955 in which case it doesn't anymore, or clobbered it,
3956 so the next insn can't use it. */
3959 if (libcall_is_dead)
3961 prev = propagate_block_delete_libcall (pbi->bb, insn, note);
3962 insn = NEXT_INSN (prev);
3965 propagate_block_delete_insn (pbi->bb, insn);
3970 /* See if this is an increment or decrement that can be merged into
3971 a following memory address. */
3974 register rtx x = single_set (insn);
3976 /* Does this instruction increment or decrement a register? */
3977 if ((flags & PROP_AUTOINC)
3979 && GET_CODE (SET_DEST (x)) == REG
3980 && (GET_CODE (SET_SRC (x)) == PLUS
3981 || GET_CODE (SET_SRC (x)) == MINUS)
3982 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
3983 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
3984 /* Ok, look for a following memory ref we can combine with.
3985 If one is found, change the memory ref to a PRE_INC
3986 or PRE_DEC, cancel this insn, and return 1.
3987 Return 0 if nothing has been done. */
3988 && try_pre_increment_1 (pbi, insn))
3991 #endif /* AUTO_INC_DEC */
3993 CLEAR_REG_SET (pbi->new_set);
3995 /* If this is not the final pass, and this insn is copying the value of
3996 a library call and it's dead, don't scan the insns that perform the
3997 library call, so that the call's arguments are not marked live. */
3998 if (libcall_is_dead)
4000 /* Record the death of the dest reg. */
4001 mark_set_regs (pbi, PATTERN (insn), insn);
4003 insn = XEXP (note, 0);
4004 return PREV_INSN (insn);
4006 else if (GET_CODE (PATTERN (insn)) == SET
4007 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
4008 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
4009 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
4010 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
4011 /* We have an insn to pop a constant amount off the stack.
4012 (Such insns use PLUS regardless of the direction of the stack,
4013 and any insn to adjust the stack by a constant is always a pop.)
4014 These insns, if not dead stores, have no effect on life. */
4018 /* Any regs live at the time of a call instruction must not go
4019 in a register clobbered by calls. Find all regs now live and
4020 record this for them. */
4022 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
4023 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
4024 { REG_N_CALLS_CROSSED (i)++; });
4026 /* Record sets. Do this even for dead instructions, since they
4027 would have killed the values if they hadn't been deleted. */
4028 mark_set_regs (pbi, PATTERN (insn), insn);
4030 if (GET_CODE (insn) == CALL_INSN)
4036 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
4037 cond = COND_EXEC_TEST (PATTERN (insn));
4039 /* Non-constant calls clobber memory. */
4040 if (! CONST_CALL_P (insn))
4042 free_EXPR_LIST_list (&pbi->mem_set_list);
4043 pbi->mem_set_list_len = 0;
4046 /* There may be extra registers to be clobbered. */
4047 for (note = CALL_INSN_FUNCTION_USAGE (insn);
4049 note = XEXP (note, 1))
4050 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
4051 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
4052 cond, insn, pbi->flags);
4054 /* Calls change all call-used and global registers. */
4055 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
4056 if (call_used_regs[i] && ! global_regs[i]
4059 /* We do not want REG_UNUSED notes for these registers. */
4060 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
4062 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
4066 /* If an insn doesn't use CC0, it becomes dead since we assume
4067 that every insn clobbers it. So show it dead here;
4068 mark_used_regs will set it live if it is referenced. */
4073 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
4075 /* Sometimes we may have inserted something before INSN (such as a move)
4076 when we make an auto-inc. So ensure we will scan those insns. */
4078 prev = PREV_INSN (insn);
4081 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
4087 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
4088 cond = COND_EXEC_TEST (PATTERN (insn));
4090 /* Calls use their arguments. */
4091 for (note = CALL_INSN_FUNCTION_USAGE (insn);
4093 note = XEXP (note, 1))
4094 if (GET_CODE (XEXP (note, 0)) == USE)
4095 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
4098 /* The stack ptr is used (honorarily) by a CALL insn. */
4099 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
4101 /* Calls may also reference any of the global registers,
4102 so they are made live. */
4103 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
4105 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
4110 /* On final pass, update counts of how many insns in which each reg
4112 if (flags & PROP_REG_INFO)
4113 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
4114 { REG_LIVE_LENGTH (i)++; });
4119 /* Initialize a propagate_block_info struct for public consumption.
4120 Note that the structure itself is opaque to this file, but that
4121 the user can use the regsets provided here. */
4123 struct propagate_block_info *
4124 init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
4126 regset live, local_set, cond_local_set;
4129 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
4132 pbi->reg_live = live;
4133 pbi->mem_set_list = NULL_RTX;
4134 pbi->mem_set_list_len = 0;
4135 pbi->local_set = local_set;
4136 pbi->cond_local_set = cond_local_set;
4140 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4141 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
4143 pbi->reg_next_use = NULL;
4145 pbi->new_set = BITMAP_XMALLOC ();
4147 #ifdef HAVE_conditional_execution
4148 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
4149 free_reg_cond_life_info);
4150 pbi->reg_cond_reg = BITMAP_XMALLOC ();
4152 /* If this block ends in a conditional branch, for each register live
4153 from one side of the branch and not the other, record the register
4154 as conditionally dead. */
4155 if (GET_CODE (bb->end) == JUMP_INSN
4156 && any_condjump_p (bb->end))
4158 regset_head diff_head;
4159 regset diff = INITIALIZE_REG_SET (diff_head);
4160 basic_block bb_true, bb_false;
4161 rtx cond_true, cond_false, set_src;
4164 /* Identify the successor blocks. */
4165 bb_true = bb->succ->dest;
4166 if (bb->succ->succ_next != NULL)
4168 bb_false = bb->succ->succ_next->dest;
4170 if (bb->succ->flags & EDGE_FALLTHRU)
4172 basic_block t = bb_false;
4176 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
4181 /* This can happen with a conditional jump to the next insn. */
4182 if (JUMP_LABEL (bb->end) != bb_true->head)
4185 /* Simplest way to do nothing. */
4189 /* Extract the condition from the branch. */
4190 set_src = SET_SRC (pc_set (bb->end));
4191 cond_true = XEXP (set_src, 0);
4192 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
4193 GET_MODE (cond_true), XEXP (cond_true, 0),
4194 XEXP (cond_true, 1));
4195 if (GET_CODE (XEXP (set_src, 1)) == PC)
4198 cond_false = cond_true;
4202 /* Compute which register lead different lives in the successors. */
4203 if (bitmap_operation (diff, bb_true->global_live_at_start,
4204 bb_false->global_live_at_start, BITMAP_XOR))
4206 rtx reg = XEXP (cond_true, 0);
4208 if (GET_CODE (reg) == SUBREG)
4209 reg = SUBREG_REG (reg);
4211 if (GET_CODE (reg) != REG)
4214 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
4216 /* For each such register, mark it conditionally dead. */
4217 EXECUTE_IF_SET_IN_REG_SET
4220 struct reg_cond_life_info *rcli;
4223 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
4225 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
4229 rcli->condition = cond;
4230 rcli->stores = const0_rtx;
4231 rcli->orig_condition = cond;
4233 splay_tree_insert (pbi->reg_cond_dead, i,
4234 (splay_tree_value) rcli);
4238 FREE_REG_SET (diff);
4242 /* If this block has no successors, any stores to the frame that aren't
4243 used later in the block are dead. So make a pass over the block
4244 recording any such that are made and show them dead at the end. We do
4245 a very conservative and simple job here. */
4247 && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
4248 && (TYPE_RETURNS_STACK_DEPRESSED
4249 (TREE_TYPE (current_function_decl))))
4250 && (flags & PROP_SCAN_DEAD_CODE)
4251 && (bb->succ == NULL
4252 || (bb->succ->succ_next == NULL
4253 && bb->succ->dest == EXIT_BLOCK_PTR)))
4256 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
4257 if (GET_CODE (insn) == INSN
4258 && (set = single_set (insn))
4259 && GET_CODE (SET_DEST (set)) == MEM)
4261 rtx mem = SET_DEST (set);
4262 rtx canon_mem = canon_rtx (mem);
4264 /* This optimization is performed by faking a store to the
4265 memory at the end of the block. This doesn't work for
4266 unchanging memories because multiple stores to unchanging
4267 memory is illegal and alias analysis doesn't consider it. */
4268 if (RTX_UNCHANGING_P (canon_mem))
4271 if (XEXP (canon_mem, 0) == frame_pointer_rtx
4272 || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
4273 && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
4274 && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
4277 /* Store a copy of mem, otherwise the address may be scrogged
4278 by find_auto_inc. This matters because insn_dead_p uses
4279 an rtx_equal_p check to determine if two addresses are
4280 the same. This works before find_auto_inc, but fails
4281 after find_auto_inc, causing discrepencies between the
4282 set of live registers calculated during the
4283 calculate_global_regs_live phase and what actually exists
4284 after flow completes, leading to aborts. */
4285 if (flags & PROP_AUTOINC)
4286 mem = shallow_copy_rtx (mem);
4288 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
4289 if (++pbi->mem_set_list_len >= MAX_MEM_SET_LIST_LEN)
4298 /* Release a propagate_block_info struct. */
4301 free_propagate_block_info (pbi)
4302 struct propagate_block_info *pbi;
4304 free_EXPR_LIST_list (&pbi->mem_set_list);
4306 BITMAP_XFREE (pbi->new_set);
4308 #ifdef HAVE_conditional_execution
4309 splay_tree_delete (pbi->reg_cond_dead);
4310 BITMAP_XFREE (pbi->reg_cond_reg);
4313 if (pbi->reg_next_use)
4314 free (pbi->reg_next_use);
4319 /* Compute the registers live at the beginning of a basic block BB from
4320 those live at the end.
4322 When called, REG_LIVE contains those live at the end. On return, it
4323 contains those live at the beginning.
4325 LOCAL_SET, if non-null, will be set with all registers killed
4326 unconditionally by this basic block.
4327 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
4328 killed conditionally by this basic block. If there is any unconditional
4329 set of a register, then the corresponding bit will be set in LOCAL_SET
4330 and cleared in COND_LOCAL_SET.
4331 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
4332 case, the resulting set will be equal to the union of the two sets that
4333 would otherwise be computed. */
4336 propagate_block (bb, live, local_set, cond_local_set, flags)
4340 regset cond_local_set;
4343 struct propagate_block_info *pbi;
4346 pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
4348 if (flags & PROP_REG_INFO)
4352 /* Process the regs live at the end of the block.
4353 Mark them as not local to any one basic block. */
4354 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
4355 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
4358 /* Scan the block an insn at a time from end to beginning. */
4360 for (insn = bb->end;; insn = prev)
4362 /* If this is a call to `setjmp' et al, warn if any
4363 non-volatile datum is live. */
4364 if ((flags & PROP_REG_INFO)
4365 && GET_CODE (insn) == NOTE
4366 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
4367 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
4369 prev = propagate_one_insn (pbi, insn);
4371 if (insn == bb->head)
4375 free_propagate_block_info (pbi);
4378 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
4379 (SET expressions whose destinations are registers dead after the insn).
4380 NEEDED is the regset that says which regs are alive after the insn.
4382 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
4384 If X is the entire body of an insn, NOTES contains the reg notes
4385 pertaining to the insn. */
4388 insn_dead_p (pbi, x, call_ok, notes)
4389 struct propagate_block_info *pbi;
4392 rtx notes ATTRIBUTE_UNUSED;
4394 enum rtx_code code = GET_CODE (x);
4397 /* If flow is invoked after reload, we must take existing AUTO_INC
4398 expresions into account. */
4399 if (reload_completed)
4401 for (; notes; notes = XEXP (notes, 1))
4403 if (REG_NOTE_KIND (notes) == REG_INC)
4405 int regno = REGNO (XEXP (notes, 0));
4407 /* Don't delete insns to set global regs. */
4408 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
4409 || REGNO_REG_SET_P (pbi->reg_live, regno))
4416 /* If setting something that's a reg or part of one,
4417 see if that register's altered value will be live. */
4421 rtx r = SET_DEST (x);
4424 if (GET_CODE (r) == CC0)
4425 return ! pbi->cc0_live;
4428 /* A SET that is a subroutine call cannot be dead. */
4429 if (GET_CODE (SET_SRC (x)) == CALL)
4435 /* Don't eliminate loads from volatile memory or volatile asms. */
4436 else if (volatile_refs_p (SET_SRC (x)))
4439 if (GET_CODE (r) == MEM)
4443 if (MEM_VOLATILE_P (r))
4446 /* Walk the set of memory locations we are currently tracking
4447 and see if one is an identical match to this memory location.
4448 If so, this memory write is dead (remember, we're walking
4449 backwards from the end of the block to the start). Since
4450 rtx_equal_p does not check the alias set or flags, we also
4451 must have the potential for them to conflict (anti_dependence). */
4452 for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
4453 if (anti_dependence (r, XEXP (temp, 0)))
4455 rtx mem = XEXP (temp, 0);
4457 if (rtx_equal_p (mem, r))
4460 /* Check if memory reference matches an auto increment. Only
4461 post increment/decrement or modify are valid. */
4462 if (GET_MODE (mem) == GET_MODE (r)
4463 && (GET_CODE (XEXP (mem, 0)) == POST_DEC
4464 || GET_CODE (XEXP (mem, 0)) == POST_INC
4465 || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
4466 && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
4467 && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
4474 while (GET_CODE (r) == SUBREG
4475 || GET_CODE (r) == STRICT_LOW_PART
4476 || GET_CODE (r) == ZERO_EXTRACT)
4479 if (GET_CODE (r) == REG)
4481 int regno = REGNO (r);
4484 if (REGNO_REG_SET_P (pbi->reg_live, regno))
4487 /* If this is a hard register, verify that subsequent
4488 words are not needed. */
4489 if (regno < FIRST_PSEUDO_REGISTER)
4491 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
4494 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
4498 /* Don't delete insns to set global regs. */
4499 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
4502 /* Make sure insns to set the stack pointer aren't deleted. */
4503 if (regno == STACK_POINTER_REGNUM)
4506 /* ??? These bits might be redundant with the force live bits
4507 in calculate_global_regs_live. We would delete from
4508 sequential sets; whether this actually affects real code
4509 for anything but the stack pointer I don't know. */
4510 /* Make sure insns to set the frame pointer aren't deleted. */
4511 if (regno == FRAME_POINTER_REGNUM
4512 && (! reload_completed || frame_pointer_needed))
4514 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4515 if (regno == HARD_FRAME_POINTER_REGNUM
4516 && (! reload_completed || frame_pointer_needed))
4520 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4521 /* Make sure insns to set arg pointer are never deleted
4522 (if the arg pointer isn't fixed, there will be a USE
4523 for it, so we can treat it normally). */
4524 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
4528 /* Otherwise, the set is dead. */
4534 /* If performing several activities, insn is dead if each activity
4535 is individually dead. Also, CLOBBERs and USEs can be ignored; a
4536 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
4538 else if (code == PARALLEL)
4540 int i = XVECLEN (x, 0);
4542 for (i--; i >= 0; i--)
4543 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
4544 && GET_CODE (XVECEXP (x, 0, i)) != USE
4545 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
4551 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
4552 is not necessarily true for hard registers. */
4553 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
4554 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
4555 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
4558 /* We do not check other CLOBBER or USE here. An insn consisting of just
4559 a CLOBBER or just a USE should not be deleted. */
4563 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
4564 return 1 if the entire library call is dead.
4565 This is true if INSN copies a register (hard or pseudo)
4566 and if the hard return reg of the call insn is dead.
4567 (The caller should have tested the destination of the SET inside
4568 INSN already for death.)
4570 If this insn doesn't just copy a register, then we don't
4571 have an ordinary libcall. In that case, cse could not have
4572 managed to substitute the source for the dest later on,
4573 so we can assume the libcall is dead.
4575 PBI is the block info giving pseudoregs live before this insn.
4576 NOTE is the REG_RETVAL note of the insn. */
4579 libcall_dead_p (pbi, note, insn)
4580 struct propagate_block_info *pbi;
4584 rtx x = single_set (insn);
4588 register rtx r = SET_SRC (x);
4589 if (GET_CODE (r) == REG)
4591 rtx call = XEXP (note, 0);
4595 /* Find the call insn. */
4596 while (call != insn && GET_CODE (call) != CALL_INSN)
4597 call = NEXT_INSN (call);
4599 /* If there is none, do nothing special,
4600 since ordinary death handling can understand these insns. */
4604 /* See if the hard reg holding the value is dead.
4605 If this is a PARALLEL, find the call within it. */
4606 call_pat = PATTERN (call);
4607 if (GET_CODE (call_pat) == PARALLEL)
4609 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
4610 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
4611 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
4614 /* This may be a library call that is returning a value
4615 via invisible pointer. Do nothing special, since
4616 ordinary death handling can understand these insns. */
4620 call_pat = XVECEXP (call_pat, 0, i);
4623 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
4629 /* Return 1 if register REGNO was used before it was set, i.e. if it is
4630 live at function entry. Don't count global register variables, variables
4631 in registers that can be used for function arg passing, or variables in
4632 fixed hard registers. */
4635 regno_uninitialized (regno)
4638 if (n_basic_blocks == 0
4639 || (regno < FIRST_PSEUDO_REGISTER
4640 && (global_regs[regno]
4641 || fixed_regs[regno]
4642 || FUNCTION_ARG_REGNO_P (regno))))
4645 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
4648 /* 1 if register REGNO was alive at a place where `setjmp' was called
4649 and was set more than once or is an argument.
4650 Such regs may be clobbered by `longjmp'. */
4653 regno_clobbered_at_setjmp (regno)
4656 if (n_basic_blocks == 0)
4659 return ((REG_N_SETS (regno) > 1
4660 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
4661 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
4664 /* INSN references memory, possibly using autoincrement addressing modes.
4665 Find any entries on the mem_set_list that need to be invalidated due
4666 to an address change. */
4669 invalidate_mems_from_autoinc (pbi, insn)
4670 struct propagate_block_info *pbi;
4673 rtx note = REG_NOTES (insn);
4674 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
4676 if (REG_NOTE_KIND (note) == REG_INC)
4678 rtx temp = pbi->mem_set_list;
4679 rtx prev = NULL_RTX;
4684 next = XEXP (temp, 1);
4685 if (reg_overlap_mentioned_p (XEXP (note, 0), XEXP (temp, 0)))
4687 /* Splice temp out of list. */
4689 XEXP (prev, 1) = next;
4691 pbi->mem_set_list = next;
4692 free_EXPR_LIST_node (temp);
4693 pbi->mem_set_list_len--;
4703 /* EXP is either a MEM or a REG. Remove any dependant entries
4704 from pbi->mem_set_list. */
4707 invalidate_mems_from_set (pbi, exp)
4708 struct propagate_block_info *pbi;
4711 rtx temp = pbi->mem_set_list;
4712 rtx prev = NULL_RTX;
4717 next = XEXP (temp, 1);
4718 if ((GET_CODE (exp) == MEM
4719 && output_dependence (XEXP (temp, 0), exp))
4720 || (GET_CODE (exp) == REG
4721 && reg_overlap_mentioned_p (exp, XEXP (temp, 0))))
4723 /* Splice this entry out of the list. */
4725 XEXP (prev, 1) = next;
4727 pbi->mem_set_list = next;
4728 free_EXPR_LIST_node (temp);
4729 pbi->mem_set_list_len--;
4737 /* Process the registers that are set within X. Their bits are set to
4738 1 in the regset DEAD, because they are dead prior to this insn.
4740 If INSN is nonzero, it is the insn being processed.
4742 FLAGS is the set of operations to perform. */
4745 mark_set_regs (pbi, x, insn)
4746 struct propagate_block_info *pbi;
4749 rtx cond = NULL_RTX;
4754 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
4756 if (REG_NOTE_KIND (link) == REG_INC)
4757 mark_set_1 (pbi, SET, XEXP (link, 0),
4758 (GET_CODE (x) == COND_EXEC
4759 ? COND_EXEC_TEST (x) : NULL_RTX),
4763 switch (code = GET_CODE (x))
4767 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
4771 cond = COND_EXEC_TEST (x);
4772 x = COND_EXEC_CODE (x);
4778 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
4780 rtx sub = XVECEXP (x, 0, i);
4781 switch (code = GET_CODE (sub))
4784 if (cond != NULL_RTX)
4787 cond = COND_EXEC_TEST (sub);
4788 sub = COND_EXEC_CODE (sub);
4789 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
4795 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
4810 /* Process a single SET rtx, X. */
4813 mark_set_1 (pbi, code, reg, cond, insn, flags)
4814 struct propagate_block_info *pbi;
4816 rtx reg, cond, insn;
4819 int regno_first = -1, regno_last = -1;
4820 unsigned long not_dead = 0;
4823 /* Modifying just one hardware register of a multi-reg value or just a
4824 byte field of a register does not mean the value from before this insn
4825 is now dead. Of course, if it was dead after it's unused now. */
4827 switch (GET_CODE (reg))
4830 /* Some targets place small structures in registers for return values of
4831 functions. We have to detect this case specially here to get correct
4832 flow information. */
4833 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
4834 if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
4835 mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
4841 case STRICT_LOW_PART:
4842 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
4844 reg = XEXP (reg, 0);
4845 while (GET_CODE (reg) == SUBREG
4846 || GET_CODE (reg) == ZERO_EXTRACT
4847 || GET_CODE (reg) == SIGN_EXTRACT
4848 || GET_CODE (reg) == STRICT_LOW_PART);
4849 if (GET_CODE (reg) == MEM)
4851 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
4855 regno_last = regno_first = REGNO (reg);
4856 if (regno_first < FIRST_PSEUDO_REGISTER)
4857 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
4861 if (GET_CODE (SUBREG_REG (reg)) == REG)
4863 enum machine_mode outer_mode = GET_MODE (reg);
4864 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
4866 /* Identify the range of registers affected. This is moderately
4867 tricky for hard registers. See alter_subreg. */
4869 regno_last = regno_first = REGNO (SUBREG_REG (reg));
4870 if (regno_first < FIRST_PSEUDO_REGISTER)
4872 #ifdef ALTER_HARD_SUBREG
4873 regno_first = ALTER_HARD_SUBREG (outer_mode, SUBREG_WORD (reg),
4874 inner_mode, regno_first);
4876 regno_first += SUBREG_WORD (reg);
4878 regno_last = (regno_first
4879 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
4881 /* Since we've just adjusted the register number ranges, make
4882 sure REG matches. Otherwise some_was_live will be clear
4883 when it shouldn't have been, and we'll create incorrect
4884 REG_UNUSED notes. */
4885 reg = gen_rtx_REG (outer_mode, regno_first);
4889 /* If the number of words in the subreg is less than the number
4890 of words in the full register, we have a well-defined partial
4891 set. Otherwise the high bits are undefined.
4893 This is only really applicable to pseudos, since we just took
4894 care of multi-word hard registers. */
4895 if (((GET_MODE_SIZE (outer_mode)
4896 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
4897 < ((GET_MODE_SIZE (inner_mode)
4898 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
4899 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
4902 reg = SUBREG_REG (reg);
4906 reg = SUBREG_REG (reg);
4913 /* If this set is a MEM, then it kills any aliased writes.
4914 If this set is a REG, then it kills any MEMs which use the reg. */
4915 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
4917 if (GET_CODE (reg) == MEM || GET_CODE (reg) == REG)
4918 invalidate_mems_from_set (pbi, reg);
4920 /* If the memory reference had embedded side effects (autoincrement
4921 address modes. Then we may need to kill some entries on the
4923 if (insn && GET_CODE (reg) == MEM)
4924 invalidate_mems_from_autoinc (pbi, insn);
4926 if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN
4927 && GET_CODE (reg) == MEM && ! side_effects_p (reg)
4928 /* ??? With more effort we could track conditional memory life. */
4930 /* We do not know the size of a BLKmode store, so we do not track
4931 them for redundant store elimination. */
4932 && GET_MODE (reg) != BLKmode
4933 /* There are no REG_INC notes for SP, so we can't assume we'll see
4934 everything that invalidates it. To be safe, don't eliminate any
4935 stores though SP; none of them should be redundant anyway. */
4936 && ! reg_mentioned_p (stack_pointer_rtx, reg))
4939 /* Store a copy of mem, otherwise the address may be
4940 scrogged by find_auto_inc. */
4941 if (flags & PROP_AUTOINC)
4942 reg = shallow_copy_rtx (reg);
4944 pbi->mem_set_list = alloc_EXPR_LIST (0, reg, pbi->mem_set_list);
4945 pbi->mem_set_list_len++;
4949 if (GET_CODE (reg) == REG
4950 && ! (regno_first == FRAME_POINTER_REGNUM
4951 && (! reload_completed || frame_pointer_needed))
4952 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4953 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
4954 && (! reload_completed || frame_pointer_needed))
4956 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4957 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
4961 int some_was_live = 0, some_was_dead = 0;
4963 for (i = regno_first; i <= regno_last; ++i)
4965 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
4968 /* Order of the set operation matters here since both
4969 sets may be the same. */
4970 CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
4971 if (cond != NULL_RTX
4972 && ! REGNO_REG_SET_P (pbi->local_set, i))
4973 SET_REGNO_REG_SET (pbi->cond_local_set, i);
4975 SET_REGNO_REG_SET (pbi->local_set, i);
4977 if (code != CLOBBER)
4978 SET_REGNO_REG_SET (pbi->new_set, i);
4980 some_was_live |= needed_regno;
4981 some_was_dead |= ! needed_regno;
4984 #ifdef HAVE_conditional_execution
4985 /* Consider conditional death in deciding that the register needs
4987 if (some_was_live && ! not_dead
4988 /* The stack pointer is never dead. Well, not strictly true,
4989 but it's very difficult to tell from here. Hopefully
4990 combine_stack_adjustments will fix up the most egregious
4992 && regno_first != STACK_POINTER_REGNUM)
4994 for (i = regno_first; i <= regno_last; ++i)
4995 if (! mark_regno_cond_dead (pbi, i, cond))
4996 not_dead |= ((unsigned long) 1) << (i - regno_first);
5000 /* Additional data to record if this is the final pass. */
5001 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
5002 | PROP_DEATH_NOTES | PROP_AUTOINC))
5005 register int blocknum = pbi->bb->index;
5008 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
5010 y = pbi->reg_next_use[regno_first];
5012 /* The next use is no longer next, since a store intervenes. */
5013 for (i = regno_first; i <= regno_last; ++i)
5014 pbi->reg_next_use[i] = 0;
5017 if (flags & PROP_REG_INFO)
5019 for (i = regno_first; i <= regno_last; ++i)
5021 /* Count (weighted) references, stores, etc. This counts a
5022 register twice if it is modified, but that is correct. */
5023 REG_N_SETS (i) += 1;
5024 REG_N_REFS (i) += (optimize_size ? 1
5025 : pbi->bb->loop_depth + 1);
5027 /* The insns where a reg is live are normally counted
5028 elsewhere, but we want the count to include the insn
5029 where the reg is set, and the normal counting mechanism
5030 would not count it. */
5031 REG_LIVE_LENGTH (i) += 1;
5034 /* If this is a hard reg, record this function uses the reg. */
5035 if (regno_first < FIRST_PSEUDO_REGISTER)
5037 for (i = regno_first; i <= regno_last; i++)
5038 regs_ever_live[i] = 1;
5042 /* Keep track of which basic blocks each reg appears in. */
5043 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
5044 REG_BASIC_BLOCK (regno_first) = blocknum;
5045 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
5046 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
5050 if (! some_was_dead)
5052 if (flags & PROP_LOG_LINKS)
5054 /* Make a logical link from the next following insn
5055 that uses this register, back to this insn.
5056 The following insns have already been processed.
5058 We don't build a LOG_LINK for hard registers containing
5059 in ASM_OPERANDs. If these registers get replaced,
5060 we might wind up changing the semantics of the insn,
5061 even if reload can make what appear to be valid
5062 assignments later. */
5063 if (y && (BLOCK_NUM (y) == blocknum)
5064 && (regno_first >= FIRST_PSEUDO_REGISTER
5065 || asm_noperands (PATTERN (y)) < 0))
5066 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
5071 else if (! some_was_live)
5073 if (flags & PROP_REG_INFO)
5074 REG_N_DEATHS (regno_first) += 1;
5076 if (flags & PROP_DEATH_NOTES)
5078 /* Note that dead stores have already been deleted
5079 when possible. If we get here, we have found a
5080 dead store that cannot be eliminated (because the
5081 same insn does something useful). Indicate this
5082 by marking the reg being set as dying here. */
5084 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
5089 if (flags & PROP_DEATH_NOTES)
5091 /* This is a case where we have a multi-word hard register
5092 and some, but not all, of the words of the register are
5093 needed in subsequent insns. Write REG_UNUSED notes
5094 for those parts that were not needed. This case should
5097 for (i = regno_first; i <= regno_last; ++i)
5098 if (! REGNO_REG_SET_P (pbi->reg_live, i))
5100 = alloc_EXPR_LIST (REG_UNUSED,
5101 gen_rtx_REG (reg_raw_mode[i], i),
5107 /* Mark the register as being dead. */
5109 /* The stack pointer is never dead. Well, not strictly true,
5110 but it's very difficult to tell from here. Hopefully
5111 combine_stack_adjustments will fix up the most egregious
5113 && regno_first != STACK_POINTER_REGNUM)
5115 for (i = regno_first; i <= regno_last; ++i)
5116 if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
5117 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
5120 else if (GET_CODE (reg) == REG)
5122 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
5123 pbi->reg_next_use[regno_first] = 0;
5126 /* If this is the last pass and this is a SCRATCH, show it will be dying
5127 here and count it. */
5128 else if (GET_CODE (reg) == SCRATCH)
5130 if (flags & PROP_DEATH_NOTES)
5132 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
5136 #ifdef HAVE_conditional_execution
5137 /* Mark REGNO conditionally dead.
5138 Return true if the register is now unconditionally dead. */
5141 mark_regno_cond_dead (pbi, regno, cond)
5142 struct propagate_block_info *pbi;
5146 /* If this is a store to a predicate register, the value of the
5147 predicate is changing, we don't know that the predicate as seen
5148 before is the same as that seen after. Flush all dependent
5149 conditions from reg_cond_dead. This will make all such
5150 conditionally live registers unconditionally live. */
5151 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
5152 flush_reg_cond_reg (pbi, regno);
5154 /* If this is an unconditional store, remove any conditional
5155 life that may have existed. */
5156 if (cond == NULL_RTX)
5157 splay_tree_remove (pbi->reg_cond_dead, regno);
5160 splay_tree_node node;
5161 struct reg_cond_life_info *rcli;
5164 /* Otherwise this is a conditional set. Record that fact.
5165 It may have been conditionally used, or there may be a
5166 subsequent set with a complimentary condition. */
5168 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
5171 /* The register was unconditionally live previously.
5172 Record the current condition as the condition under
5173 which it is dead. */
5174 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
5175 rcli->condition = cond;
5176 rcli->stores = cond;
5177 rcli->orig_condition = const0_rtx;
5178 splay_tree_insert (pbi->reg_cond_dead, regno,
5179 (splay_tree_value) rcli);
5181 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5183 /* Not unconditionaly dead. */
5188 /* The register was conditionally live previously.
5189 Add the new condition to the old. */
5190 rcli = (struct reg_cond_life_info *) node->value;
5191 ncond = rcli->condition;
5192 ncond = ior_reg_cond (ncond, cond, 1);
5193 if (rcli->stores == const0_rtx)
5194 rcli->stores = cond;
5195 else if (rcli->stores != const1_rtx)
5196 rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
5198 /* If the register is now unconditionally dead, remove the entry
5199 in the splay_tree. A register is unconditionally dead if the
5200 dead condition ncond is true. A register is also unconditionally
5201 dead if the sum of all conditional stores is an unconditional
5202 store (stores is true), and the dead condition is identically the
5203 same as the original dead condition initialized at the end of
5204 the block. This is a pointer compare, not an rtx_equal_p
5206 if (ncond == const1_rtx
5207 || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
5208 splay_tree_remove (pbi->reg_cond_dead, regno);
5211 rcli->condition = ncond;
5213 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5215 /* Not unconditionaly dead. */
5224 /* Called from splay_tree_delete for pbi->reg_cond_life. */
5227 free_reg_cond_life_info (value)
5228 splay_tree_value value;
5230 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
5234 /* Helper function for flush_reg_cond_reg. */
5237 flush_reg_cond_reg_1 (node, data)
5238 splay_tree_node node;
5241 struct reg_cond_life_info *rcli;
5242 int *xdata = (int *) data;
5243 unsigned int regno = xdata[0];
5245 /* Don't need to search if last flushed value was farther on in
5246 the in-order traversal. */
5247 if (xdata[1] >= (int) node->key)
5250 /* Splice out portions of the expression that refer to regno. */
5251 rcli = (struct reg_cond_life_info *) node->value;
5252 rcli->condition = elim_reg_cond (rcli->condition, regno);
5253 if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
5254 rcli->stores = elim_reg_cond (rcli->stores, regno);
5256 /* If the entire condition is now false, signal the node to be removed. */
5257 if (rcli->condition == const0_rtx)
5259 xdata[1] = node->key;
5262 else if (rcli->condition == const1_rtx)
5268 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
5271 flush_reg_cond_reg (pbi, regno)
5272 struct propagate_block_info *pbi;
5279 while (splay_tree_foreach (pbi->reg_cond_dead,
5280 flush_reg_cond_reg_1, pair) == -1)
5281 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
5283 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
5286 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
5287 For ior/and, the ADD flag determines whether we want to add the new
5288 condition X to the old one unconditionally. If it is zero, we will
5289 only return a new expression if X allows us to simplify part of
5290 OLD, otherwise we return OLD unchanged to the caller.
5291 If ADD is nonzero, we will return a new condition in all cases. The
5292 toplevel caller of one of these functions should always pass 1 for
5296 ior_reg_cond (old, x, add)
5302 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
5304 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
5305 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
5306 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5308 if (GET_CODE (x) == GET_CODE (old)
5309 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5313 return gen_rtx_IOR (0, old, x);
5316 switch (GET_CODE (old))
5319 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
5320 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
5321 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5323 if (op0 == const0_rtx)
5325 if (op1 == const0_rtx)
5327 if (op0 == const1_rtx || op1 == const1_rtx)
5329 if (op0 == XEXP (old, 0))
5330 op0 = gen_rtx_IOR (0, op0, x);
5332 op1 = gen_rtx_IOR (0, op1, x);
5333 return gen_rtx_IOR (0, op0, op1);
5337 return gen_rtx_IOR (0, old, x);
5340 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
5341 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
5342 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5344 if (op0 == const1_rtx)
5346 if (op1 == const1_rtx)
5348 if (op0 == const0_rtx || op1 == const0_rtx)
5350 if (op0 == XEXP (old, 0))
5351 op0 = gen_rtx_IOR (0, op0, x);
5353 op1 = gen_rtx_IOR (0, op1, x);
5354 return gen_rtx_AND (0, op0, op1);
5358 return gen_rtx_IOR (0, old, x);
5361 op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
5362 if (op0 != XEXP (old, 0))
5363 return not_reg_cond (op0);
5366 return gen_rtx_IOR (0, old, x);
5377 enum rtx_code x_code;
5379 if (x == const0_rtx)
5381 else if (x == const1_rtx)
5383 x_code = GET_CODE (x);
5386 if (GET_RTX_CLASS (x_code) == '<'
5387 && GET_CODE (XEXP (x, 0)) == REG)
5389 if (XEXP (x, 1) != const0_rtx)
5392 return gen_rtx_fmt_ee (reverse_condition (x_code),
5393 VOIDmode, XEXP (x, 0), const0_rtx);
5395 return gen_rtx_NOT (0, x);
5399 and_reg_cond (old, x, add)
5405 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
5407 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
5408 && GET_CODE (x) == reverse_condition (GET_CODE (old))
5409 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5411 if (GET_CODE (x) == GET_CODE (old)
5412 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5416 return gen_rtx_AND (0, old, x);
5419 switch (GET_CODE (old))
5422 op0 = and_reg_cond (XEXP (old, 0), x, 0);
5423 op1 = and_reg_cond (XEXP (old, 1), x, 0);
5424 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5426 if (op0 == const0_rtx)
5428 if (op1 == const0_rtx)
5430 if (op0 == const1_rtx || op1 == const1_rtx)
5432 if (op0 == XEXP (old, 0))
5433 op0 = gen_rtx_AND (0, op0, x);
5435 op1 = gen_rtx_AND (0, op1, x);
5436 return gen_rtx_IOR (0, op0, op1);
5440 return gen_rtx_AND (0, old, x);
5443 op0 = and_reg_cond (XEXP (old, 0), x, 0);
5444 op1 = and_reg_cond (XEXP (old, 1), x, 0);
5445 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5447 if (op0 == const1_rtx)
5449 if (op1 == const1_rtx)
5451 if (op0 == const0_rtx || op1 == const0_rtx)
5453 if (op0 == XEXP (old, 0))
5454 op0 = gen_rtx_AND (0, op0, x);
5456 op1 = gen_rtx_AND (0, op1, x);
5457 return gen_rtx_AND (0, op0, op1);
5462 /* If X is identical to one of the existing terms of the AND,
5463 then just return what we already have. */
5464 /* ??? There really should be some sort of recursive check here in
5465 case there are nested ANDs. */
5466 if ((GET_CODE (XEXP (old, 0)) == GET_CODE (x)
5467 && REGNO (XEXP (XEXP (old, 0), 0)) == REGNO (XEXP (x, 0)))
5468 || (GET_CODE (XEXP (old, 1)) == GET_CODE (x)
5469 && REGNO (XEXP (XEXP (old, 1), 0)) == REGNO (XEXP (x, 0))))
5472 return gen_rtx_AND (0, old, x);
5475 op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
5476 if (op0 != XEXP (old, 0))
5477 return not_reg_cond (op0);
5480 return gen_rtx_AND (0, old, x);
5487 /* Given a condition X, remove references to reg REGNO and return the
5488 new condition. The removal will be done so that all conditions
5489 involving REGNO are considered to evaluate to false. This function
5490 is used when the value of REGNO changes. */
5493 elim_reg_cond (x, regno)
5499 if (GET_RTX_CLASS (GET_CODE (x)) == '<')
5501 if (REGNO (XEXP (x, 0)) == regno)
5506 switch (GET_CODE (x))
5509 op0 = elim_reg_cond (XEXP (x, 0), regno);
5510 op1 = elim_reg_cond (XEXP (x, 1), regno);
5511 if (op0 == const0_rtx || op1 == const0_rtx)
5513 if (op0 == const1_rtx)
5515 if (op1 == const1_rtx)
5517 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
5519 return gen_rtx_AND (0, op0, op1);
5522 op0 = elim_reg_cond (XEXP (x, 0), regno);
5523 op1 = elim_reg_cond (XEXP (x, 1), regno);
5524 if (op0 == const1_rtx || op1 == const1_rtx)
5526 if (op0 == const0_rtx)
5528 if (op1 == const0_rtx)
5530 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
5532 return gen_rtx_IOR (0, op0, op1);
5535 op0 = elim_reg_cond (XEXP (x, 0), regno);
5536 if (op0 == const0_rtx)
5538 if (op0 == const1_rtx)
5540 if (op0 != XEXP (x, 0))
5541 return not_reg_cond (op0);
5548 #endif /* HAVE_conditional_execution */
5552 /* Try to substitute the auto-inc expression INC as the address inside
5553 MEM which occurs in INSN. Currently, the address of MEM is an expression
5554 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
5555 that has a single set whose source is a PLUS of INCR_REG and something
5559 attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
5560 struct propagate_block_info *pbi;
5561 rtx inc, insn, mem, incr, incr_reg;
5563 int regno = REGNO (incr_reg);
5564 rtx set = single_set (incr);
5565 rtx q = SET_DEST (set);
5566 rtx y = SET_SRC (set);
5567 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
5569 /* Make sure this reg appears only once in this insn. */
5570 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
5573 if (dead_or_set_p (incr, incr_reg)
5574 /* Mustn't autoinc an eliminable register. */
5575 && (regno >= FIRST_PSEUDO_REGISTER
5576 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
5578 /* This is the simple case. Try to make the auto-inc. If
5579 we can't, we are done. Otherwise, we will do any
5580 needed updates below. */
5581 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
5584 else if (GET_CODE (q) == REG
5585 /* PREV_INSN used here to check the semi-open interval
5587 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
5588 /* We must also check for sets of q as q may be
5589 a call clobbered hard register and there may
5590 be a call between PREV_INSN (insn) and incr. */
5591 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
5593 /* We have *p followed sometime later by q = p+size.
5594 Both p and q must be live afterward,
5595 and q is not used between INSN and its assignment.
5596 Change it to q = p, ...*q..., q = q+size.
5597 Then fall into the usual case. */
5601 emit_move_insn (q, incr_reg);
5602 insns = get_insns ();
5605 if (basic_block_for_insn)
5606 for (temp = insns; temp; temp = NEXT_INSN (temp))
5607 set_block_for_insn (temp, pbi->bb);
5609 /* If we can't make the auto-inc, or can't make the
5610 replacement into Y, exit. There's no point in making
5611 the change below if we can't do the auto-inc and doing
5612 so is not correct in the pre-inc case. */
5615 validate_change (insn, &XEXP (mem, 0), inc, 1);
5616 validate_change (incr, &XEXP (y, opnum), q, 1);
5617 if (! apply_change_group ())
5620 /* We now know we'll be doing this change, so emit the
5621 new insn(s) and do the updates. */
5622 emit_insns_before (insns, insn);
5624 if (pbi->bb->head == insn)
5625 pbi->bb->head = insns;
5627 /* INCR will become a NOTE and INSN won't contain a
5628 use of INCR_REG. If a use of INCR_REG was just placed in
5629 the insn before INSN, make that the next use.
5630 Otherwise, invalidate it. */
5631 if (GET_CODE (PREV_INSN (insn)) == INSN
5632 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
5633 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
5634 pbi->reg_next_use[regno] = PREV_INSN (insn);
5636 pbi->reg_next_use[regno] = 0;
5641 /* REGNO is now used in INCR which is below INSN, but
5642 it previously wasn't live here. If we don't mark
5643 it as live, we'll put a REG_DEAD note for it
5644 on this insn, which is incorrect. */
5645 SET_REGNO_REG_SET (pbi->reg_live, regno);
5647 /* If there are any calls between INSN and INCR, show
5648 that REGNO now crosses them. */
5649 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
5650 if (GET_CODE (temp) == CALL_INSN)
5651 REG_N_CALLS_CROSSED (regno)++;
5656 /* If we haven't returned, it means we were able to make the
5657 auto-inc, so update the status. First, record that this insn
5658 has an implicit side effect. */
5660 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
5662 /* Modify the old increment-insn to simply copy
5663 the already-incremented value of our register. */
5664 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
5667 /* If that makes it a no-op (copying the register into itself) delete
5668 it so it won't appear to be a "use" and a "set" of this
5670 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
5672 /* If the original source was dead, it's dead now. */
5675 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
5677 remove_note (incr, note);
5678 if (XEXP (note, 0) != incr_reg)
5679 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
5682 PUT_CODE (incr, NOTE);
5683 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
5684 NOTE_SOURCE_FILE (incr) = 0;
5687 if (regno >= FIRST_PSEUDO_REGISTER)
5689 /* Count an extra reference to the reg. When a reg is
5690 incremented, spilling it is worse, so we want to make
5691 that less likely. */
5692 REG_N_REFS (regno) += (optimize_size ? 1 : pbi->bb->loop_depth + 1);
5694 /* Count the increment as a setting of the register,
5695 even though it isn't a SET in rtl. */
5696 REG_N_SETS (regno)++;
5700 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
5704 find_auto_inc (pbi, x, insn)
5705 struct propagate_block_info *pbi;
5709 rtx addr = XEXP (x, 0);
5710 HOST_WIDE_INT offset = 0;
5711 rtx set, y, incr, inc_val;
5713 int size = GET_MODE_SIZE (GET_MODE (x));
5715 if (GET_CODE (insn) == JUMP_INSN)
5718 /* Here we detect use of an index register which might be good for
5719 postincrement, postdecrement, preincrement, or predecrement. */
5721 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
5722 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
5724 if (GET_CODE (addr) != REG)
5727 regno = REGNO (addr);
5729 /* Is the next use an increment that might make auto-increment? */
5730 incr = pbi->reg_next_use[regno];
5731 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
5733 set = single_set (incr);
5734 if (set == 0 || GET_CODE (set) != SET)
5738 if (GET_CODE (y) != PLUS)
5741 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
5742 inc_val = XEXP (y, 1);
5743 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
5744 inc_val = XEXP (y, 0);
5748 if (GET_CODE (inc_val) == CONST_INT)
5750 if (HAVE_POST_INCREMENT
5751 && (INTVAL (inc_val) == size && offset == 0))
5752 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
5754 else if (HAVE_POST_DECREMENT
5755 && (INTVAL (inc_val) == -size && offset == 0))
5756 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
5758 else if (HAVE_PRE_INCREMENT
5759 && (INTVAL (inc_val) == size && offset == size))
5760 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
5762 else if (HAVE_PRE_DECREMENT
5763 && (INTVAL (inc_val) == -size && offset == -size))
5764 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
5766 else if (HAVE_POST_MODIFY_DISP && offset == 0)
5767 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
5768 gen_rtx_PLUS (Pmode,
5771 insn, x, incr, addr);
5773 else if (GET_CODE (inc_val) == REG
5774 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
5778 if (HAVE_POST_MODIFY_REG && offset == 0)
5779 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
5780 gen_rtx_PLUS (Pmode,
5783 insn, x, incr, addr);
5787 #endif /* AUTO_INC_DEC */
5790 mark_used_reg (pbi, reg, cond, insn)
5791 struct propagate_block_info *pbi;
5793 rtx cond ATTRIBUTE_UNUSED;
5796 int regno = REGNO (reg);
5797 int some_was_live = REGNO_REG_SET_P (pbi->reg_live, regno);
5798 int some_was_dead = ! some_was_live;
5802 /* A hard reg in a wide mode may really be multiple registers.
5803 If so, mark all of them just like the first. */
5804 if (regno < FIRST_PSEUDO_REGISTER)
5806 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5809 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, regno + n);
5810 some_was_live |= needed_regno;
5811 some_was_dead |= ! needed_regno;
5815 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
5817 /* Record where each reg is used, so when the reg is set we know
5818 the next insn that uses it. */
5819 pbi->reg_next_use[regno] = insn;
5822 if (pbi->flags & PROP_REG_INFO)
5824 if (regno < FIRST_PSEUDO_REGISTER)
5826 /* If this is a register we are going to try to eliminate,
5827 don't mark it live here. If we are successful in
5828 eliminating it, it need not be live unless it is used for
5829 pseudos, in which case it will have been set live when it
5830 was allocated to the pseudos. If the register will not
5831 be eliminated, reload will set it live at that point.
5833 Otherwise, record that this function uses this register. */
5834 /* ??? The PPC backend tries to "eliminate" on the pic
5835 register to itself. This should be fixed. In the mean
5836 time, hack around it. */
5838 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno)
5839 && (regno == FRAME_POINTER_REGNUM
5840 || regno == ARG_POINTER_REGNUM)))
5842 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5844 regs_ever_live[regno + --n] = 1;
5850 /* Keep track of which basic block each reg appears in. */
5852 register int blocknum = pbi->bb->index;
5853 if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN)
5854 REG_BASIC_BLOCK (regno) = blocknum;
5855 else if (REG_BASIC_BLOCK (regno) != blocknum)
5856 REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL;
5858 /* Count (weighted) number of uses of each reg. */
5859 REG_N_REFS (regno) += (optimize_size ? 1
5860 : pbi->bb->loop_depth + 1);
5864 /* Find out if any of the register was set this insn. */
5865 some_not_set = ! REGNO_REG_SET_P (pbi->new_set, regno);
5866 if (regno < FIRST_PSEUDO_REGISTER)
5868 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5870 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, regno + n);
5873 /* Record and count the insns in which a reg dies. If it is used in
5874 this insn and was dead below the insn then it dies in this insn.
5875 If it was set in this insn, we do not make a REG_DEAD note;
5876 likewise if we already made such a note. */
5877 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
5881 /* Check for the case where the register dying partially
5882 overlaps the register set by this insn. */
5883 if (regno < FIRST_PSEUDO_REGISTER
5884 && HARD_REGNO_NREGS (regno, GET_MODE (reg)) > 1)
5886 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5888 some_was_live |= REGNO_REG_SET_P (pbi->new_set, regno + n);
5891 /* If none of the words in X is needed, make a REG_DEAD note.
5892 Otherwise, we must make partial REG_DEAD notes. */
5893 if (! some_was_live)
5895 if ((pbi->flags & PROP_DEATH_NOTES)
5896 && ! find_regno_note (insn, REG_DEAD, regno))
5898 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
5900 if (pbi->flags & PROP_REG_INFO)
5901 REG_N_DEATHS (regno)++;
5905 /* Don't make a REG_DEAD note for a part of a register
5906 that is set in the insn. */
5908 n = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)) - 1;
5909 for (; n >= regno; n--)
5910 if (! REGNO_REG_SET_P (pbi->reg_live, n)
5911 && ! dead_or_set_regno_p (insn, n))
5913 = alloc_EXPR_LIST (REG_DEAD,
5914 gen_rtx_REG (reg_raw_mode[n], n),
5919 SET_REGNO_REG_SET (pbi->reg_live, regno);
5920 if (regno < FIRST_PSEUDO_REGISTER)
5922 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5924 SET_REGNO_REG_SET (pbi->reg_live, regno + n);
5927 #ifdef HAVE_conditional_execution
5928 /* If this is a conditional use, record that fact. If it is later
5929 conditionally set, we'll know to kill the register. */
5930 if (cond != NULL_RTX)
5932 splay_tree_node node;
5933 struct reg_cond_life_info *rcli;
5938 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
5941 /* The register was unconditionally live previously.
5942 No need to do anything. */
5946 /* The register was conditionally live previously.
5947 Subtract the new life cond from the old death cond. */
5948 rcli = (struct reg_cond_life_info *) node->value;
5949 ncond = rcli->condition;
5950 ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
5952 /* If the register is now unconditionally live, remove the
5953 entry in the splay_tree. */
5954 if (ncond == const0_rtx)
5955 splay_tree_remove (pbi->reg_cond_dead, regno);
5958 rcli->condition = ncond;
5959 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5965 /* The register was not previously live at all. Record
5966 the condition under which it is still dead. */
5967 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
5968 rcli->condition = not_reg_cond (cond);
5969 rcli->stores = const0_rtx;
5970 rcli->orig_condition = const0_rtx;
5971 splay_tree_insert (pbi->reg_cond_dead, regno,
5972 (splay_tree_value) rcli);
5974 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5977 else if (some_was_live)
5979 splay_tree_node node;
5981 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
5984 /* The register was conditionally live previously, but is now
5985 unconditionally so. Remove it from the conditionally dead
5986 list, so that a conditional set won't cause us to think
5988 splay_tree_remove (pbi->reg_cond_dead, regno);
5995 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
5996 This is done assuming the registers needed from X are those that
5997 have 1-bits in PBI->REG_LIVE.
5999 INSN is the containing instruction. If INSN is dead, this function
6003 mark_used_regs (pbi, x, cond, insn)
6004 struct propagate_block_info *pbi;
6007 register RTX_CODE code;
6009 int flags = pbi->flags;
6012 code = GET_CODE (x);
6032 /* If we are clobbering a MEM, mark any registers inside the address
6034 if (GET_CODE (XEXP (x, 0)) == MEM)
6035 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
6039 /* Don't bother watching stores to mems if this is not the
6040 final pass. We'll not be deleting dead stores this round. */
6041 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
6043 /* Invalidate the data for the last MEM stored, but only if MEM is
6044 something that can be stored into. */
6045 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
6046 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
6047 /* Needn't clear the memory set list. */
6051 rtx temp = pbi->mem_set_list;
6052 rtx prev = NULL_RTX;
6057 next = XEXP (temp, 1);
6058 if (anti_dependence (XEXP (temp, 0), x))
6060 /* Splice temp out of the list. */
6062 XEXP (prev, 1) = next;
6064 pbi->mem_set_list = next;
6065 free_EXPR_LIST_node (temp);
6066 pbi->mem_set_list_len--;
6074 /* If the memory reference had embedded side effects (autoincrement
6075 address modes. Then we may need to kill some entries on the
6078 invalidate_mems_from_autoinc (pbi, insn);
6082 if (flags & PROP_AUTOINC)
6083 find_auto_inc (pbi, x, insn);
6088 #ifdef CLASS_CANNOT_CHANGE_MODE
6089 if (GET_CODE (SUBREG_REG (x)) == REG
6090 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
6091 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
6092 GET_MODE (SUBREG_REG (x))))
6093 REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
6096 /* While we're here, optimize this case. */
6098 if (GET_CODE (x) != REG)
6103 /* See a register other than being set => mark it as needed. */
6104 mark_used_reg (pbi, x, cond, insn);
6109 register rtx testreg = SET_DEST (x);
6112 /* If storing into MEM, don't show it as being used. But do
6113 show the address as being used. */
6114 if (GET_CODE (testreg) == MEM)
6117 if (flags & PROP_AUTOINC)
6118 find_auto_inc (pbi, testreg, insn);
6120 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
6121 mark_used_regs (pbi, SET_SRC (x), cond, insn);
6125 /* Storing in STRICT_LOW_PART is like storing in a reg
6126 in that this SET might be dead, so ignore it in TESTREG.
6127 but in some other ways it is like using the reg.
6129 Storing in a SUBREG or a bit field is like storing the entire
6130 register in that if the register's value is not used
6131 then this SET is not needed. */
6132 while (GET_CODE (testreg) == STRICT_LOW_PART
6133 || GET_CODE (testreg) == ZERO_EXTRACT
6134 || GET_CODE (testreg) == SIGN_EXTRACT
6135 || GET_CODE (testreg) == SUBREG)
6137 #ifdef CLASS_CANNOT_CHANGE_MODE
6138 if (GET_CODE (testreg) == SUBREG
6139 && GET_CODE (SUBREG_REG (testreg)) == REG
6140 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
6141 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
6142 GET_MODE (testreg)))
6143 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
6146 /* Modifying a single register in an alternate mode
6147 does not use any of the old value. But these other
6148 ways of storing in a register do use the old value. */
6149 if (GET_CODE (testreg) == SUBREG
6150 && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
6155 testreg = XEXP (testreg, 0);
6158 /* If this is a store into a register or group of registers,
6159 recursively scan the value being stored. */
6161 if ((GET_CODE (testreg) == PARALLEL
6162 && GET_MODE (testreg) == BLKmode)
6163 || (GET_CODE (testreg) == REG
6164 && (regno = REGNO (testreg),
6165 ! (regno == FRAME_POINTER_REGNUM
6166 && (! reload_completed || frame_pointer_needed)))
6167 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
6168 && ! (regno == HARD_FRAME_POINTER_REGNUM
6169 && (! reload_completed || frame_pointer_needed))
6171 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
6172 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
6177 mark_used_regs (pbi, SET_DEST (x), cond, insn);
6178 mark_used_regs (pbi, SET_SRC (x), cond, insn);
6185 case UNSPEC_VOLATILE:
6189 /* Traditional and volatile asm instructions must be considered to use
6190 and clobber all hard registers, all pseudo-registers and all of
6191 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
6193 Consider for instance a volatile asm that changes the fpu rounding
6194 mode. An insn should not be moved across this even if it only uses
6195 pseudo-regs because it might give an incorrectly rounded result.
6197 ?!? Unfortunately, marking all hard registers as live causes massive
6198 problems for the register allocator and marking all pseudos as live
6199 creates mountains of uninitialized variable warnings.
6201 So for now, just clear the memory set list and mark any regs
6202 we can find in ASM_OPERANDS as used. */
6203 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
6205 free_EXPR_LIST_list (&pbi->mem_set_list);
6206 pbi->mem_set_list_len = 0;
6209 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
6210 We can not just fall through here since then we would be confused
6211 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
6212 traditional asms unlike their normal usage. */
6213 if (code == ASM_OPERANDS)
6217 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
6218 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
6224 if (cond != NULL_RTX)
6227 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
6229 cond = COND_EXEC_TEST (x);
6230 x = COND_EXEC_CODE (x);
6234 /* We _do_not_ want to scan operands of phi nodes. Operands of
6235 a phi function are evaluated only when control reaches this
6236 block along a particular edge. Therefore, regs that appear
6237 as arguments to phi should not be added to the global live at
6245 /* Recursively scan the operands of this expression. */
6248 register const char *fmt = GET_RTX_FORMAT (code);
6251 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
6255 /* Tail recursive case: save a function call level. */
6261 mark_used_regs (pbi, XEXP (x, i), cond, insn);
6263 else if (fmt[i] == 'E')
6266 for (j = 0; j < XVECLEN (x, i); j++)
6267 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
6276 try_pre_increment_1 (pbi, insn)
6277 struct propagate_block_info *pbi;
6280 /* Find the next use of this reg. If in same basic block,
6281 make it do pre-increment or pre-decrement if appropriate. */
6282 rtx x = single_set (insn);
6283 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
6284 * INTVAL (XEXP (SET_SRC (x), 1)));
6285 int regno = REGNO (SET_DEST (x));
6286 rtx y = pbi->reg_next_use[regno];
6288 && SET_DEST (x) != stack_pointer_rtx
6289 && BLOCK_NUM (y) == BLOCK_NUM (insn)
6290 /* Don't do this if the reg dies, or gets set in y; a standard addressing
6291 mode would be better. */
6292 && ! dead_or_set_p (y, SET_DEST (x))
6293 && try_pre_increment (y, SET_DEST (x), amount))
6295 /* We have found a suitable auto-increment and already changed
6296 insn Y to do it. So flush this increment instruction. */
6297 propagate_block_delete_insn (pbi->bb, insn);
6299 /* Count a reference to this reg for the increment insn we are
6300 deleting. When a reg is incremented, spilling it is worse,
6301 so we want to make that less likely. */
6302 if (regno >= FIRST_PSEUDO_REGISTER)
6304 REG_N_REFS (regno) += (optimize_size ? 1
6305 : pbi->bb->loop_depth + 1);
6306 REG_N_SETS (regno)++;
6309 /* Flush any remembered memories depending on the value of
6310 the incremented register. */
6311 invalidate_mems_from_set (pbi, SET_DEST (x));
6318 /* Try to change INSN so that it does pre-increment or pre-decrement
6319 addressing on register REG in order to add AMOUNT to REG.
6320 AMOUNT is negative for pre-decrement.
6321 Returns 1 if the change could be made.
6322 This checks all about the validity of the result of modifying INSN. */
6325 try_pre_increment (insn, reg, amount)
6327 HOST_WIDE_INT amount;
6331 /* Nonzero if we can try to make a pre-increment or pre-decrement.
6332 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
6334 /* Nonzero if we can try to make a post-increment or post-decrement.
6335 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
6336 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
6337 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
6340 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
6343 /* From the sign of increment, see which possibilities are conceivable
6344 on this target machine. */
6345 if (HAVE_PRE_INCREMENT && amount > 0)
6347 if (HAVE_POST_INCREMENT && amount > 0)
6350 if (HAVE_PRE_DECREMENT && amount < 0)
6352 if (HAVE_POST_DECREMENT && amount < 0)
6355 if (! (pre_ok || post_ok))
6358 /* It is not safe to add a side effect to a jump insn
6359 because if the incremented register is spilled and must be reloaded
6360 there would be no way to store the incremented value back in memory. */
6362 if (GET_CODE (insn) == JUMP_INSN)
6367 use = find_use_as_address (PATTERN (insn), reg, 0);
6368 if (post_ok && (use == 0 || use == (rtx) 1))
6370 use = find_use_as_address (PATTERN (insn), reg, -amount);
6374 if (use == 0 || use == (rtx) 1)
6377 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
6380 /* See if this combination of instruction and addressing mode exists. */
6381 if (! validate_change (insn, &XEXP (use, 0),
6382 gen_rtx_fmt_e (amount > 0
6383 ? (do_post ? POST_INC : PRE_INC)
6384 : (do_post ? POST_DEC : PRE_DEC),
6388 /* Record that this insn now has an implicit side effect on X. */
6389 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
6393 #endif /* AUTO_INC_DEC */
6395 /* Find the place in the rtx X where REG is used as a memory address.
6396 Return the MEM rtx that so uses it.
6397 If PLUSCONST is nonzero, search instead for a memory address equivalent to
6398 (plus REG (const_int PLUSCONST)).
6400 If such an address does not appear, return 0.
6401 If REG appears more than once, or is used other than in such an address,
6405 find_use_as_address (x, reg, plusconst)
6408 HOST_WIDE_INT plusconst;
6410 enum rtx_code code = GET_CODE (x);
6411 const char *fmt = GET_RTX_FORMAT (code);
6413 register rtx value = 0;
6416 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
6419 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
6420 && XEXP (XEXP (x, 0), 0) == reg
6421 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
6422 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
6425 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
6427 /* If REG occurs inside a MEM used in a bit-field reference,
6428 that is unacceptable. */
6429 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
6430 return (rtx) (HOST_WIDE_INT) 1;
6434 return (rtx) (HOST_WIDE_INT) 1;
6436 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
6440 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
6444 return (rtx) (HOST_WIDE_INT) 1;
6446 else if (fmt[i] == 'E')
6449 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
6451 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
6455 return (rtx) (HOST_WIDE_INT) 1;
6463 /* Write information about registers and basic blocks into FILE.
6464 This is part of making a debugging dump. */
6467 dump_regset (r, outf)
6474 fputs (" (nil)", outf);
6478 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
6480 fprintf (outf, " %d", i);
6481 if (i < FIRST_PSEUDO_REGISTER)
6482 fprintf (outf, " [%s]",
6491 dump_regset (r, stderr);
6492 putc ('\n', stderr);
6496 dump_flow_info (file)
6500 static const char * const reg_class_names[] = REG_CLASS_NAMES;
6502 fprintf (file, "%d registers.\n", max_regno);
6503 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
6506 enum reg_class class, altclass;
6507 fprintf (file, "\nRegister %d used %d times across %d insns",
6508 i, REG_N_REFS (i), REG_LIVE_LENGTH (i));
6509 if (REG_BASIC_BLOCK (i) >= 0)
6510 fprintf (file, " in block %d", REG_BASIC_BLOCK (i));
6512 fprintf (file, "; set %d time%s", REG_N_SETS (i),
6513 (REG_N_SETS (i) == 1) ? "" : "s");
6514 if (REG_USERVAR_P (regno_reg_rtx[i]))
6515 fprintf (file, "; user var");
6516 if (REG_N_DEATHS (i) != 1)
6517 fprintf (file, "; dies in %d places", REG_N_DEATHS (i));
6518 if (REG_N_CALLS_CROSSED (i) == 1)
6519 fprintf (file, "; crosses 1 call");
6520 else if (REG_N_CALLS_CROSSED (i))
6521 fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i));
6522 if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
6523 fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
6524 class = reg_preferred_class (i);
6525 altclass = reg_alternate_class (i);
6526 if (class != GENERAL_REGS || altclass != ALL_REGS)
6528 if (altclass == ALL_REGS || class == ALL_REGS)
6529 fprintf (file, "; pref %s", reg_class_names[(int) class]);
6530 else if (altclass == NO_REGS)
6531 fprintf (file, "; %s or none", reg_class_names[(int) class]);
6533 fprintf (file, "; pref %s, else %s",
6534 reg_class_names[(int) class],
6535 reg_class_names[(int) altclass]);
6537 if (REG_POINTER (regno_reg_rtx[i]))
6538 fprintf (file, "; pointer");
6539 fprintf (file, ".\n");
6542 fprintf (file, "\n%d basic blocks, %d edges.\n", n_basic_blocks, n_edges);
6543 for (i = 0; i < n_basic_blocks; i++)
6545 register basic_block bb = BASIC_BLOCK (i);
6548 fprintf (file, "\nBasic block %d: first insn %d, last %d, loop_depth %d, count %d.\n",
6549 i, INSN_UID (bb->head), INSN_UID (bb->end), bb->loop_depth, bb->count);
6551 fprintf (file, "Predecessors: ");
6552 for (e = bb->pred; e; e = e->pred_next)
6553 dump_edge_info (file, e, 0);
6555 fprintf (file, "\nSuccessors: ");
6556 for (e = bb->succ; e; e = e->succ_next)
6557 dump_edge_info (file, e, 1);
6559 fprintf (file, "\nRegisters live at start:");
6560 dump_regset (bb->global_live_at_start, file);
6562 fprintf (file, "\nRegisters live at end:");
6563 dump_regset (bb->global_live_at_end, file);
6574 dump_flow_info (stderr);
6578 dump_edge_info (file, e, do_succ)
6583 basic_block side = (do_succ ? e->dest : e->src);
6585 if (side == ENTRY_BLOCK_PTR)
6586 fputs (" ENTRY", file);
6587 else if (side == EXIT_BLOCK_PTR)
6588 fputs (" EXIT", file);
6590 fprintf (file, " %d", side->index);
6593 fprintf (file, " count:%d", e->count);
6597 static const char * const bitnames[] = {
6598 "fallthru", "crit", "ab", "abcall", "eh", "fake"
6601 int i, flags = e->flags;
6605 for (i = 0; flags; i++)
6606 if (flags & (1 << i))
6612 if (i < (int) ARRAY_SIZE (bitnames))
6613 fputs (bitnames[i], file);
6615 fprintf (file, "%d", i);
6622 /* Print out one basic block with live information at start and end. */
6633 fprintf (outf, ";; Basic block %d, loop depth %d, count %d",
6634 bb->index, bb->loop_depth, bb->count);
6635 if (bb->eh_beg != -1 || bb->eh_end != -1)
6636 fprintf (outf, ", eh regions %d/%d", bb->eh_beg, bb->eh_end);
6639 fputs (";; Predecessors: ", outf);
6640 for (e = bb->pred; e; e = e->pred_next)
6641 dump_edge_info (outf, e, 0);
6644 fputs (";; Registers live at start:", outf);
6645 dump_regset (bb->global_live_at_start, outf);
6648 for (insn = bb->head, last = NEXT_INSN (bb->end);
6650 insn = NEXT_INSN (insn))
6651 print_rtl_single (outf, insn);
6653 fputs (";; Registers live at end:", outf);
6654 dump_regset (bb->global_live_at_end, outf);
6657 fputs (";; Successors: ", outf);
6658 for (e = bb->succ; e; e = e->succ_next)
6659 dump_edge_info (outf, e, 1);
6667 dump_bb (bb, stderr);
6674 dump_bb (BASIC_BLOCK (n), stderr);
6677 /* Like print_rtl, but also print out live information for the start of each
6681 print_rtl_with_bb (outf, rtx_first)
6685 register rtx tmp_rtx;
6688 fprintf (outf, "(nil)\n");
6692 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
6693 int max_uid = get_max_uid ();
6694 basic_block *start = (basic_block *)
6695 xcalloc (max_uid, sizeof (basic_block));
6696 basic_block *end = (basic_block *)
6697 xcalloc (max_uid, sizeof (basic_block));
6698 enum bb_state *in_bb_p = (enum bb_state *)
6699 xcalloc (max_uid, sizeof (enum bb_state));
6701 for (i = n_basic_blocks - 1; i >= 0; i--)
6703 basic_block bb = BASIC_BLOCK (i);
6706 start[INSN_UID (bb->head)] = bb;
6707 end[INSN_UID (bb->end)] = bb;
6708 for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x))
6710 enum bb_state state = IN_MULTIPLE_BB;
6711 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
6713 in_bb_p[INSN_UID (x)] = state;
6720 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
6725 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
6727 fprintf (outf, ";; Start of basic block %d, registers live:",
6729 dump_regset (bb->global_live_at_start, outf);
6733 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
6734 && GET_CODE (tmp_rtx) != NOTE
6735 && GET_CODE (tmp_rtx) != BARRIER)
6736 fprintf (outf, ";; Insn is not within a basic block\n");
6737 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
6738 fprintf (outf, ";; Insn is in multiple basic blocks\n");
6740 did_output = print_rtl_single (outf, tmp_rtx);
6742 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
6744 fprintf (outf, ";; End of basic block %d, registers live:\n",
6746 dump_regset (bb->global_live_at_end, outf);
6759 if (current_function_epilogue_delay_list != 0)
6761 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
6762 for (tmp_rtx = current_function_epilogue_delay_list; tmp_rtx != 0;
6763 tmp_rtx = XEXP (tmp_rtx, 1))
6764 print_rtl_single (outf, XEXP (tmp_rtx, 0));
6768 /* Dump the rtl into the current debugging dump file, then abort. */
6771 print_rtl_and_abort_fcn (file, line, function)
6774 const char *function;
6778 print_rtl_with_bb (rtl_dump_file, get_insns ());
6779 fclose (rtl_dump_file);
6782 fancy_abort (file, line, function);
6785 /* Recompute register set/reference counts immediately prior to register
6788 This avoids problems with set/reference counts changing to/from values
6789 which have special meanings to the register allocators.
6791 Additionally, the reference counts are the primary component used by the
6792 register allocators to prioritize pseudos for allocation to hard regs.
6793 More accurate reference counts generally lead to better register allocation.
6795 F is the first insn to be scanned.
6797 LOOP_STEP denotes how much loop_depth should be incremented per
6798 loop nesting level in order to increase the ref count more for
6799 references in a loop.
6801 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
6802 possibly other information which is used by the register allocators. */
6805 recompute_reg_usage (f, loop_step)
6806 rtx f ATTRIBUTE_UNUSED;
6807 int loop_step ATTRIBUTE_UNUSED;
6809 allocate_reg_life_data ();
6810 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
6813 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
6814 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
6815 of the number of registers that died. */
6818 count_or_remove_death_notes (blocks, kill)
6824 for (i = n_basic_blocks - 1; i >= 0; --i)
6829 if (blocks && ! TEST_BIT (blocks, i))
6832 bb = BASIC_BLOCK (i);
6834 for (insn = bb->head;; insn = NEXT_INSN (insn))
6838 rtx *pprev = ®_NOTES (insn);
6843 switch (REG_NOTE_KIND (link))
6846 if (GET_CODE (XEXP (link, 0)) == REG)
6848 rtx reg = XEXP (link, 0);
6851 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
6854 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
6862 rtx next = XEXP (link, 1);
6863 free_EXPR_LIST_node (link);
6864 *pprev = link = next;
6870 pprev = &XEXP (link, 1);
6877 if (insn == bb->end)
6886 /* Update insns block within BB. */
6889 update_bb_for_insn (bb)
6894 if (! basic_block_for_insn)
6897 for (insn = bb->head; ; insn = NEXT_INSN (insn))
6899 set_block_for_insn (insn, bb);
6901 if (insn == bb->end)
6907 /* Record INSN's block as BB. */
6910 set_block_for_insn (insn, bb)
6914 size_t uid = INSN_UID (insn);
6915 if (uid >= basic_block_for_insn->num_elements)
6919 /* Add one-eighth the size so we don't keep calling xrealloc. */
6920 new_size = uid + (uid + 7) / 8;
6922 VARRAY_GROW (basic_block_for_insn, new_size);
6924 VARRAY_BB (basic_block_for_insn, uid) = bb;
6927 /* Record INSN's block number as BB. */
6928 /* ??? This has got to go. */
6931 set_block_num (insn, bb)
6935 set_block_for_insn (insn, BASIC_BLOCK (bb));
6938 /* Verify the CFG consistency. This function check some CFG invariants and
6939 aborts when something is wrong. Hope that this function will help to
6940 convert many optimization passes to preserve CFG consistent.
6942 Currently it does following checks:
6944 - test head/end pointers
6945 - overlapping of basic blocks
6946 - edge list corectness
6947 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
6948 - tails of basic blocks (ensure that boundary is necesary)
6949 - scans body of the basic block for JUMP_INSN, CODE_LABEL
6950 and NOTE_INSN_BASIC_BLOCK
6951 - check that all insns are in the basic blocks
6952 (except the switch handling code, barriers and notes)
6953 - check that all returns are followed by barriers
6955 In future it can be extended check a lot of other stuff as well
6956 (reachability of basic blocks, life information, etc. etc.). */
6961 const int max_uid = get_max_uid ();
6962 const rtx rtx_first = get_insns ();
6963 rtx last_head = get_last_insn ();
6964 basic_block *bb_info;
6966 int i, last_bb_num_seen, num_bb_notes, err = 0;
6968 bb_info = (basic_block *) xcalloc (max_uid, sizeof (basic_block));
6970 for (i = n_basic_blocks - 1; i >= 0; i--)
6972 basic_block bb = BASIC_BLOCK (i);
6973 rtx head = bb->head;
6976 /* Verify the end of the basic block is in the INSN chain. */
6977 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
6982 error ("End insn %d for block %d not found in the insn stream.",
6983 INSN_UID (end), bb->index);
6987 /* Work backwards from the end to the head of the basic block
6988 to verify the head is in the RTL chain. */
6989 for (; x != NULL_RTX; x = PREV_INSN (x))
6991 /* While walking over the insn chain, verify insns appear
6992 in only one basic block and initialize the BB_INFO array
6993 used by other passes. */
6994 if (bb_info[INSN_UID (x)] != NULL)
6996 error ("Insn %d is in multiple basic blocks (%d and %d)",
6997 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
7000 bb_info[INSN_UID (x)] = bb;
7007 error ("Head insn %d for block %d not found in the insn stream.",
7008 INSN_UID (head), bb->index);
7015 /* Now check the basic blocks (boundaries etc.) */
7016 for (i = n_basic_blocks - 1; i >= 0; i--)
7018 basic_block bb = BASIC_BLOCK (i);
7019 /* Check corectness of edge lists */
7028 "verify_flow_info: Basic block %d succ edge is corrupted\n",
7030 fprintf (stderr, "Predecessor: ");
7031 dump_edge_info (stderr, e, 0);
7032 fprintf (stderr, "\nSuccessor: ");
7033 dump_edge_info (stderr, e, 1);
7037 if (e->dest != EXIT_BLOCK_PTR)
7039 edge e2 = e->dest->pred;
7040 while (e2 && e2 != e)
7044 error ("Basic block %i edge lists are corrupted", bb->index);
7056 error ("Basic block %d pred edge is corrupted", bb->index);
7057 fputs ("Predecessor: ", stderr);
7058 dump_edge_info (stderr, e, 0);
7059 fputs ("\nSuccessor: ", stderr);
7060 dump_edge_info (stderr, e, 1);
7061 fputc ('\n', stderr);
7064 if (e->src != ENTRY_BLOCK_PTR)
7066 edge e2 = e->src->succ;
7067 while (e2 && e2 != e)
7071 error ("Basic block %i edge lists are corrupted", bb->index);
7078 /* OK pointers are correct. Now check the header of basic
7079 block. It ought to contain optional CODE_LABEL followed
7080 by NOTE_BASIC_BLOCK. */
7082 if (GET_CODE (x) == CODE_LABEL)
7086 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
7092 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
7094 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d\n",
7101 /* Do checks for empty blocks here */
7108 if (NOTE_INSN_BASIC_BLOCK_P (x))
7110 error ("NOTE_INSN_BASIC_BLOCK %d in the middle of basic block %d",
7111 INSN_UID (x), bb->index);
7118 if (GET_CODE (x) == JUMP_INSN
7119 || GET_CODE (x) == CODE_LABEL
7120 || GET_CODE (x) == BARRIER)
7122 error ("In basic block %d:", bb->index);
7123 fatal_insn ("Flow control insn inside a basic block", x);
7131 last_bb_num_seen = -1;
7136 if (NOTE_INSN_BASIC_BLOCK_P (x))
7138 basic_block bb = NOTE_BASIC_BLOCK (x);
7140 if (bb->index != last_bb_num_seen + 1)
7141 /* Basic blocks not numbered consecutively. */
7144 last_bb_num_seen = bb->index;
7147 if (!bb_info[INSN_UID (x)])
7149 switch (GET_CODE (x))
7156 /* An addr_vec is placed outside any block block. */
7158 && GET_CODE (NEXT_INSN (x)) == JUMP_INSN
7159 && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
7160 || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
7165 /* But in any case, non-deletable labels can appear anywhere. */
7169 fatal_insn ("Insn outside basic block", x);
7174 && GET_CODE (x) == JUMP_INSN
7175 && returnjump_p (x) && ! condjump_p (x)
7176 && ! (NEXT_INSN (x) && GET_CODE (NEXT_INSN (x)) == BARRIER))
7177 fatal_insn ("Return not followed by barrier", x);
7182 if (num_bb_notes != n_basic_blocks)
7184 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
7185 num_bb_notes, n_basic_blocks);
7194 /* Functions to access an edge list with a vector representation.
7195 Enough data is kept such that given an index number, the
7196 pred and succ that edge represents can be determined, or
7197 given a pred and a succ, its index number can be returned.
7198 This allows algorithms which consume a lot of memory to
7199 represent the normally full matrix of edge (pred,succ) with a
7200 single indexed vector, edge (EDGE_INDEX (pred, succ)), with no
7201 wasted space in the client code due to sparse flow graphs. */
7203 /* This functions initializes the edge list. Basically the entire
7204 flowgraph is processed, and all edges are assigned a number,
7205 and the data structure is filled in. */
7210 struct edge_list *elist;
7216 block_count = n_basic_blocks + 2; /* Include the entry and exit blocks. */
7220 /* Determine the number of edges in the flow graph by counting successor
7221 edges on each basic block. */
7222 for (x = 0; x < n_basic_blocks; x++)
7224 basic_block bb = BASIC_BLOCK (x);
7226 for (e = bb->succ; e; e = e->succ_next)
7229 /* Don't forget successors of the entry block. */
7230 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
7233 elist = (struct edge_list *) xmalloc (sizeof (struct edge_list));
7234 elist->num_blocks = block_count;
7235 elist->num_edges = num_edges;
7236 elist->index_to_edge = (edge *) xmalloc (sizeof (edge) * num_edges);
7240 /* Follow successors of the entry block, and register these edges. */
7241 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
7243 elist->index_to_edge[num_edges] = e;
7247 for (x = 0; x < n_basic_blocks; x++)
7249 basic_block bb = BASIC_BLOCK (x);
7251 /* Follow all successors of blocks, and register these edges. */
7252 for (e = bb->succ; e; e = e->succ_next)
7254 elist->index_to_edge[num_edges] = e;
7261 /* This function free's memory associated with an edge list. */
7264 free_edge_list (elist)
7265 struct edge_list *elist;
7269 free (elist->index_to_edge);
7274 /* This function provides debug output showing an edge list. */
7277 print_edge_list (f, elist)
7279 struct edge_list *elist;
7282 fprintf (f, "Compressed edge list, %d BBs + entry & exit, and %d edges\n",
7283 elist->num_blocks - 2, elist->num_edges);
7285 for (x = 0; x < elist->num_edges; x++)
7287 fprintf (f, " %-4d - edge(", x);
7288 if (INDEX_EDGE_PRED_BB (elist, x) == ENTRY_BLOCK_PTR)
7289 fprintf (f, "entry,");
7291 fprintf (f, "%d,", INDEX_EDGE_PRED_BB (elist, x)->index);
7293 if (INDEX_EDGE_SUCC_BB (elist, x) == EXIT_BLOCK_PTR)
7294 fprintf (f, "exit)\n");
7296 fprintf (f, "%d)\n", INDEX_EDGE_SUCC_BB (elist, x)->index);
7300 /* This function provides an internal consistency check of an edge list,
7301 verifying that all edges are present, and that there are no
7305 verify_edge_list (f, elist)
7307 struct edge_list *elist;
7309 int x, pred, succ, index;
7312 for (x = 0; x < n_basic_blocks; x++)
7314 basic_block bb = BASIC_BLOCK (x);
7316 for (e = bb->succ; e; e = e->succ_next)
7318 pred = e->src->index;
7319 succ = e->dest->index;
7320 index = EDGE_INDEX (elist, e->src, e->dest);
7321 if (index == EDGE_INDEX_NO_EDGE)
7323 fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
7326 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
7327 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
7328 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
7329 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
7330 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
7331 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
7334 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
7336 pred = e->src->index;
7337 succ = e->dest->index;
7338 index = EDGE_INDEX (elist, e->src, e->dest);
7339 if (index == EDGE_INDEX_NO_EDGE)
7341 fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
7344 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
7345 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
7346 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
7347 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
7348 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
7349 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
7351 /* We've verified that all the edges are in the list, no lets make sure
7352 there are no spurious edges in the list. */
7354 for (pred = 0; pred < n_basic_blocks; pred++)
7355 for (succ = 0; succ < n_basic_blocks; succ++)
7357 basic_block p = BASIC_BLOCK (pred);
7358 basic_block s = BASIC_BLOCK (succ);
7362 for (e = p->succ; e; e = e->succ_next)
7368 for (e = s->pred; e; e = e->pred_next)
7374 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
7375 == EDGE_INDEX_NO_EDGE && found_edge != 0)
7376 fprintf (f, "*** Edge (%d, %d) appears to not have an index\n",
7378 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
7379 != EDGE_INDEX_NO_EDGE && found_edge == 0)
7380 fprintf (f, "*** Edge (%d, %d) has index %d, but there is no edge\n",
7381 pred, succ, EDGE_INDEX (elist, BASIC_BLOCK (pred),
7382 BASIC_BLOCK (succ)));
7384 for (succ = 0; succ < n_basic_blocks; succ++)
7386 basic_block p = ENTRY_BLOCK_PTR;
7387 basic_block s = BASIC_BLOCK (succ);
7391 for (e = p->succ; e; e = e->succ_next)
7397 for (e = s->pred; e; e = e->pred_next)
7403 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
7404 == EDGE_INDEX_NO_EDGE && found_edge != 0)
7405 fprintf (f, "*** Edge (entry, %d) appears to not have an index\n",
7407 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
7408 != EDGE_INDEX_NO_EDGE && found_edge == 0)
7409 fprintf (f, "*** Edge (entry, %d) has index %d, but no edge exists\n",
7410 succ, EDGE_INDEX (elist, ENTRY_BLOCK_PTR,
7411 BASIC_BLOCK (succ)));
7413 for (pred = 0; pred < n_basic_blocks; pred++)
7415 basic_block p = BASIC_BLOCK (pred);
7416 basic_block s = EXIT_BLOCK_PTR;
7420 for (e = p->succ; e; e = e->succ_next)
7426 for (e = s->pred; e; e = e->pred_next)
7432 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
7433 == EDGE_INDEX_NO_EDGE && found_edge != 0)
7434 fprintf (f, "*** Edge (%d, exit) appears to not have an index\n",
7436 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
7437 != EDGE_INDEX_NO_EDGE && found_edge == 0)
7438 fprintf (f, "*** Edge (%d, exit) has index %d, but no edge exists\n",
7439 pred, EDGE_INDEX (elist, BASIC_BLOCK (pred),
7444 /* This routine will determine what, if any, edge there is between
7445 a specified predecessor and successor. */
7448 find_edge_index (edge_list, pred, succ)
7449 struct edge_list *edge_list;
7450 basic_block pred, succ;
7453 for (x = 0; x < NUM_EDGES (edge_list); x++)
7455 if (INDEX_EDGE_PRED_BB (edge_list, x) == pred
7456 && INDEX_EDGE_SUCC_BB (edge_list, x) == succ)
7459 return (EDGE_INDEX_NO_EDGE);
7462 /* This function will remove an edge from the flow graph. */
7468 edge last_pred = NULL;
7469 edge last_succ = NULL;
7471 basic_block src, dest;
7474 for (tmp = src->succ; tmp && tmp != e; tmp = tmp->succ_next)
7480 last_succ->succ_next = e->succ_next;
7482 src->succ = e->succ_next;
7484 for (tmp = dest->pred; tmp && tmp != e; tmp = tmp->pred_next)
7490 last_pred->pred_next = e->pred_next;
7492 dest->pred = e->pred_next;
7498 /* This routine will remove any fake successor edges for a basic block.
7499 When the edge is removed, it is also removed from whatever predecessor
7503 remove_fake_successors (bb)
7507 for (e = bb->succ; e;)
7511 if ((tmp->flags & EDGE_FAKE) == EDGE_FAKE)
7516 /* This routine will remove all fake edges from the flow graph. If
7517 we remove all fake successors, it will automatically remove all
7518 fake predecessors. */
7521 remove_fake_edges ()
7525 for (x = 0; x < n_basic_blocks; x++)
7526 remove_fake_successors (BASIC_BLOCK (x));
7528 /* We've handled all successors except the entry block's. */
7529 remove_fake_successors (ENTRY_BLOCK_PTR);
7532 /* This function will add a fake edge between any block which has no
7533 successors, and the exit block. Some data flow equations require these
7537 add_noreturn_fake_exit_edges ()
7541 for (x = 0; x < n_basic_blocks; x++)
7542 if (BASIC_BLOCK (x)->succ == NULL)
7543 make_edge (NULL, BASIC_BLOCK (x), EXIT_BLOCK_PTR, EDGE_FAKE);
7546 /* This function adds a fake edge between any infinite loops to the
7547 exit block. Some optimizations require a path from each node to
7550 See also Morgan, Figure 3.10, pp. 82-83.
7552 The current implementation is ugly, not attempting to minimize the
7553 number of inserted fake edges. To reduce the number of fake edges
7554 to insert, add fake edges from _innermost_ loops containing only
7555 nodes not reachable from the exit block. */
7558 connect_infinite_loops_to_exit ()
7560 basic_block unvisited_block;
7562 /* Perform depth-first search in the reverse graph to find nodes
7563 reachable from the exit block. */
7564 struct depth_first_search_dsS dfs_ds;
7566 flow_dfs_compute_reverse_init (&dfs_ds);
7567 flow_dfs_compute_reverse_add_bb (&dfs_ds, EXIT_BLOCK_PTR);
7569 /* Repeatedly add fake edges, updating the unreachable nodes. */
7572 unvisited_block = flow_dfs_compute_reverse_execute (&dfs_ds);
7573 if (!unvisited_block)
7575 make_edge (NULL, unvisited_block, EXIT_BLOCK_PTR, EDGE_FAKE);
7576 flow_dfs_compute_reverse_add_bb (&dfs_ds, unvisited_block);
7579 flow_dfs_compute_reverse_finish (&dfs_ds);
7584 /* Redirect an edge's successor from one block to another. */
7587 redirect_edge_succ (e, new_succ)
7589 basic_block new_succ;
7593 /* Disconnect the edge from the old successor block. */
7594 for (pe = &e->dest->pred; *pe != e; pe = &(*pe)->pred_next)
7596 *pe = (*pe)->pred_next;
7598 /* Reconnect the edge to the new successor block. */
7599 e->pred_next = new_succ->pred;
7604 /* Redirect an edge's predecessor from one block to another. */
7607 redirect_edge_pred (e, new_pred)
7609 basic_block new_pred;
7613 /* Disconnect the edge from the old predecessor block. */
7614 for (pe = &e->src->succ; *pe != e; pe = &(*pe)->succ_next)
7616 *pe = (*pe)->succ_next;
7618 /* Reconnect the edge to the new predecessor block. */
7619 e->succ_next = new_pred->succ;
7624 /* Dump the list of basic blocks in the bitmap NODES. */
7627 flow_nodes_print (str, nodes, file)
7629 const sbitmap nodes;
7637 fprintf (file, "%s { ", str);
7638 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {fprintf (file, "%d ", node);});
7639 fputs ("}\n", file);
7643 /* Dump the list of edges in the array EDGE_LIST. */
7646 flow_edge_list_print (str, edge_list, num_edges, file)
7648 const edge *edge_list;
7657 fprintf (file, "%s { ", str);
7658 for (i = 0; i < num_edges; i++)
7659 fprintf (file, "%d->%d ", edge_list[i]->src->index,
7660 edge_list[i]->dest->index);
7661 fputs ("}\n", file);
7665 /* Dump loop related CFG information. */
7668 flow_loops_cfg_dump (loops, file)
7669 const struct loops *loops;
7674 if (! loops->num || ! file || ! loops->cfg.dom)
7677 for (i = 0; i < n_basic_blocks; i++)
7681 fprintf (file, ";; %d succs { ", i);
7682 for (succ = BASIC_BLOCK (i)->succ; succ; succ = succ->succ_next)
7683 fprintf (file, "%d ", succ->dest->index);
7684 flow_nodes_print ("} dom", loops->cfg.dom[i], file);
7687 /* Dump the DFS node order. */
7688 if (loops->cfg.dfs_order)
7690 fputs (";; DFS order: ", file);
7691 for (i = 0; i < n_basic_blocks; i++)
7692 fprintf (file, "%d ", loops->cfg.dfs_order[i]);
7695 /* Dump the reverse completion node order. */
7696 if (loops->cfg.rc_order)
7698 fputs (";; RC order: ", file);
7699 for (i = 0; i < n_basic_blocks; i++)
7700 fprintf (file, "%d ", loops->cfg.rc_order[i]);
7705 /* Return non-zero if the nodes of LOOP are a subset of OUTER. */
7708 flow_loop_nested_p (outer, loop)
7712 return sbitmap_a_subset_b_p (loop->nodes, outer->nodes);
7716 /* Dump the loop information specified by LOOP to the stream FILE
7717 using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
7719 flow_loop_dump (loop, file, loop_dump_aux, verbose)
7720 const struct loop *loop;
7722 void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
7725 if (! loop || ! loop->header)
7728 fprintf (file, ";;\n;; Loop %d (%d to %d):%s%s\n",
7729 loop->num, INSN_UID (loop->first->head),
7730 INSN_UID (loop->last->end),
7731 loop->shared ? " shared" : "",
7732 loop->invalid ? " invalid" : "");
7733 fprintf (file, ";; header %d, latch %d, pre-header %d, first %d, last %d\n",
7734 loop->header->index, loop->latch->index,
7735 loop->pre_header ? loop->pre_header->index : -1,
7736 loop->first->index, loop->last->index);
7737 fprintf (file, ";; depth %d, level %d, outer %ld\n",
7738 loop->depth, loop->level,
7739 (long) (loop->outer ? loop->outer->num : -1));
7741 if (loop->pre_header_edges)
7742 flow_edge_list_print (";; pre-header edges", loop->pre_header_edges,
7743 loop->num_pre_header_edges, file);
7744 flow_edge_list_print (";; entry edges", loop->entry_edges,
7745 loop->num_entries, file);
7746 fprintf (file, ";; %d", loop->num_nodes);
7747 flow_nodes_print (" nodes", loop->nodes, file);
7748 flow_edge_list_print (";; exit edges", loop->exit_edges,
7749 loop->num_exits, file);
7750 if (loop->exits_doms)
7751 flow_nodes_print (";; exit doms", loop->exits_doms, file);
7753 loop_dump_aux (loop, file, verbose);
7757 /* Dump the loop information specified by LOOPS to the stream FILE,
7758 using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
7760 flow_loops_dump (loops, file, loop_dump_aux, verbose)
7761 const struct loops *loops;
7763 void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
7769 num_loops = loops->num;
7770 if (! num_loops || ! file)
7773 fprintf (file, ";; %d loops found, %d levels\n",
7774 num_loops, loops->levels);
7776 for (i = 0; i < num_loops; i++)
7778 struct loop *loop = &loops->array[i];
7780 flow_loop_dump (loop, file, loop_dump_aux, verbose);
7786 for (j = 0; j < i; j++)
7788 struct loop *oloop = &loops->array[j];
7790 if (loop->header == oloop->header)
7795 smaller = loop->num_nodes < oloop->num_nodes;
7797 /* If the union of LOOP and OLOOP is different than
7798 the larger of LOOP and OLOOP then LOOP and OLOOP
7799 must be disjoint. */
7800 disjoint = ! flow_loop_nested_p (smaller ? loop : oloop,
7801 smaller ? oloop : loop);
7803 ";; loop header %d shared by loops %d, %d %s\n",
7804 loop->header->index, i, j,
7805 disjoint ? "disjoint" : "nested");
7812 flow_loops_cfg_dump (loops, file);
7816 /* Free all the memory allocated for LOOPS. */
7819 flow_loops_free (loops)
7820 struct loops *loops;
7829 /* Free the loop descriptors. */
7830 for (i = 0; i < loops->num; i++)
7832 struct loop *loop = &loops->array[i];
7834 if (loop->pre_header_edges)
7835 free (loop->pre_header_edges);
7837 sbitmap_free (loop->nodes);
7838 if (loop->entry_edges)
7839 free (loop->entry_edges);
7840 if (loop->exit_edges)
7841 free (loop->exit_edges);
7842 if (loop->exits_doms)
7843 sbitmap_free (loop->exits_doms);
7845 free (loops->array);
7846 loops->array = NULL;
7849 sbitmap_vector_free (loops->cfg.dom);
7850 if (loops->cfg.dfs_order)
7851 free (loops->cfg.dfs_order);
7853 if (loops->shared_headers)
7854 sbitmap_free (loops->shared_headers);
7859 /* Find the entry edges into the loop with header HEADER and nodes
7860 NODES and store in ENTRY_EDGES array. Return the number of entry
7861 edges from the loop. */
7864 flow_loop_entry_edges_find (header, nodes, entry_edges)
7866 const sbitmap nodes;
7872 *entry_edges = NULL;
7875 for (e = header->pred; e; e = e->pred_next)
7877 basic_block src = e->src;
7879 if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
7886 *entry_edges = (edge *) xmalloc (num_entries * sizeof (edge *));
7889 for (e = header->pred; e; e = e->pred_next)
7891 basic_block src = e->src;
7893 if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
7894 (*entry_edges)[num_entries++] = e;
7901 /* Find the exit edges from the loop using the bitmap of loop nodes
7902 NODES and store in EXIT_EDGES array. Return the number of
7903 exit edges from the loop. */
7906 flow_loop_exit_edges_find (nodes, exit_edges)
7907 const sbitmap nodes;
7916 /* Check all nodes within the loop to see if there are any
7917 successors not in the loop. Note that a node may have multiple
7918 exiting edges ????? A node can have one jumping edge and one fallthru
7919 edge so only one of these can exit the loop. */
7921 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
7922 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
7924 basic_block dest = e->dest;
7926 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
7934 *exit_edges = (edge *) xmalloc (num_exits * sizeof (edge *));
7936 /* Store all exiting edges into an array. */
7938 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
7939 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
7941 basic_block dest = e->dest;
7943 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
7944 (*exit_edges)[num_exits++] = e;
7952 /* Find the nodes contained within the loop with header HEADER and
7953 latch LATCH and store in NODES. Return the number of nodes within
7957 flow_loop_nodes_find (header, latch, nodes)
7966 stack = (basic_block *) xmalloc (n_basic_blocks * sizeof (basic_block));
7969 /* Start with only the loop header in the set of loop nodes. */
7970 sbitmap_zero (nodes);
7971 SET_BIT (nodes, header->index);
7973 header->loop_depth++;
7975 /* Push the loop latch on to the stack. */
7976 if (! TEST_BIT (nodes, latch->index))
7978 SET_BIT (nodes, latch->index);
7979 latch->loop_depth++;
7981 stack[sp++] = latch;
7990 for (e = node->pred; e; e = e->pred_next)
7992 basic_block ancestor = e->src;
7994 /* If each ancestor not marked as part of loop, add to set of
7995 loop nodes and push on to stack. */
7996 if (ancestor != ENTRY_BLOCK_PTR
7997 && ! TEST_BIT (nodes, ancestor->index))
7999 SET_BIT (nodes, ancestor->index);
8000 ancestor->loop_depth++;
8002 stack[sp++] = ancestor;
8010 /* Compute the depth first search order and store in the array
8011 DFS_ORDER if non-zero, marking the nodes visited in VISITED. If
8012 RC_ORDER is non-zero, return the reverse completion number for each
8013 node. Returns the number of nodes visited. A depth first search
8014 tries to get as far away from the starting point as quickly as
8018 flow_depth_first_order_compute (dfs_order, rc_order)
8025 int rcnum = n_basic_blocks - 1;
8028 /* Allocate stack for back-tracking up CFG. */
8029 stack = (edge *) xmalloc ((n_basic_blocks + 1) * sizeof (edge));
8032 /* Allocate bitmap to track nodes that have been visited. */
8033 visited = sbitmap_alloc (n_basic_blocks);
8035 /* None of the nodes in the CFG have been visited yet. */
8036 sbitmap_zero (visited);
8038 /* Push the first edge on to the stack. */
8039 stack[sp++] = ENTRY_BLOCK_PTR->succ;
8047 /* Look at the edge on the top of the stack. */
8052 /* Check if the edge destination has been visited yet. */
8053 if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index))
8055 /* Mark that we have visited the destination. */
8056 SET_BIT (visited, dest->index);
8059 dfs_order[dfsnum++] = dest->index;
8063 /* Since the DEST node has been visited for the first
8064 time, check its successors. */
8065 stack[sp++] = dest->succ;
8069 /* There are no successors for the DEST node so assign
8070 its reverse completion number. */
8072 rc_order[rcnum--] = dest->index;
8077 if (! e->succ_next && src != ENTRY_BLOCK_PTR)
8079 /* There are no more successors for the SRC node
8080 so assign its reverse completion number. */
8082 rc_order[rcnum--] = src->index;
8086 stack[sp - 1] = e->succ_next;
8093 sbitmap_free (visited);
8095 /* The number of nodes visited should not be greater than
8097 if (dfsnum > n_basic_blocks)
8100 /* There are some nodes left in the CFG that are unreachable. */
8101 if (dfsnum < n_basic_blocks)
8106 /* Compute the depth first search order on the _reverse_ graph and
8107 store in the array DFS_ORDER, marking the nodes visited in VISITED.
8108 Returns the number of nodes visited.
8110 The computation is split into three pieces:
8112 flow_dfs_compute_reverse_init () creates the necessary data
8115 flow_dfs_compute_reverse_add_bb () adds a basic block to the data
8116 structures. The block will start the search.
8118 flow_dfs_compute_reverse_execute () continues (or starts) the
8119 search using the block on the top of the stack, stopping when the
8122 flow_dfs_compute_reverse_finish () destroys the necessary data
8125 Thus, the user will probably call ..._init(), call ..._add_bb() to
8126 add a beginning basic block to the stack, call ..._execute(),
8127 possibly add another bb to the stack and again call ..._execute(),
8128 ..., and finally call _finish(). */
8130 /* Initialize the data structures used for depth-first search on the
8131 reverse graph. If INITIALIZE_STACK is nonzero, the exit block is
8132 added to the basic block stack. DATA is the current depth-first
8133 search context. If INITIALIZE_STACK is non-zero, there is an
8134 element on the stack. */
8137 flow_dfs_compute_reverse_init (data)
8138 depth_first_search_ds data;
8140 /* Allocate stack for back-tracking up CFG. */
8142 (basic_block *) xmalloc ((n_basic_blocks - (INVALID_BLOCK + 1))
8143 * sizeof (basic_block));
8146 /* Allocate bitmap to track nodes that have been visited. */
8147 data->visited_blocks = sbitmap_alloc (n_basic_blocks - (INVALID_BLOCK + 1));
8149 /* None of the nodes in the CFG have been visited yet. */
8150 sbitmap_zero (data->visited_blocks);
8155 /* Add the specified basic block to the top of the dfs data
8156 structures. When the search continues, it will start at the
8160 flow_dfs_compute_reverse_add_bb (data, bb)
8161 depth_first_search_ds data;
8164 data->stack[data->sp++] = bb;
8168 /* Continue the depth-first search through the reverse graph starting
8169 with the block at the stack's top and ending when the stack is
8170 empty. Visited nodes are marked. Returns an unvisited basic
8171 block, or NULL if there is none available. */
8174 flow_dfs_compute_reverse_execute (data)
8175 depth_first_search_ds data;
8181 while (data->sp > 0)
8183 bb = data->stack[--data->sp];
8185 /* Mark that we have visited this node. */
8186 if (!TEST_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1)))
8188 SET_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1));
8190 /* Perform depth-first search on adjacent vertices. */
8191 for (e = bb->pred; e; e = e->pred_next)
8192 flow_dfs_compute_reverse_add_bb (data, e->src);
8196 /* Determine if there are unvisited basic blocks. */
8197 for (i = n_basic_blocks - (INVALID_BLOCK + 1); --i >= 0;)
8198 if (!TEST_BIT (data->visited_blocks, i))
8199 return BASIC_BLOCK (i + (INVALID_BLOCK + 1));
8203 /* Destroy the data structures needed for depth-first search on the
8207 flow_dfs_compute_reverse_finish (data)
8208 depth_first_search_ds data;
8211 sbitmap_free (data->visited_blocks);
8216 /* Find the root node of the loop pre-header extended basic block and
8217 the edges along the trace from the root node to the loop header. */
8220 flow_loop_pre_header_scan (loop)
8226 loop->num_pre_header_edges = 0;
8228 if (loop->num_entries != 1)
8231 ebb = loop->entry_edges[0]->src;
8233 if (ebb != ENTRY_BLOCK_PTR)
8237 /* Count number of edges along trace from loop header to
8238 root of pre-header extended basic block. Usually this is
8239 only one or two edges. */
8241 while (ebb->pred->src != ENTRY_BLOCK_PTR && ! ebb->pred->pred_next)
8243 ebb = ebb->pred->src;
8247 loop->pre_header_edges = (edge *) xmalloc (num * sizeof (edge *));
8248 loop->num_pre_header_edges = num;
8250 /* Store edges in order that they are followed. The source
8251 of the first edge is the root node of the pre-header extended
8252 basic block and the destination of the last last edge is
8254 for (e = loop->entry_edges[0]; num; e = e->src->pred)
8256 loop->pre_header_edges[--num] = e;
8262 /* Return the block for the pre-header of the loop with header
8263 HEADER where DOM specifies the dominator information. Return NULL if
8264 there is no pre-header. */
8267 flow_loop_pre_header_find (header, dom)
8271 basic_block pre_header;
8274 /* If block p is a predecessor of the header and is the only block
8275 that the header does not dominate, then it is the pre-header. */
8277 for (e = header->pred; e; e = e->pred_next)
8279 basic_block node = e->src;
8281 if (node != ENTRY_BLOCK_PTR
8282 && ! TEST_BIT (dom[node->index], header->index))
8284 if (pre_header == NULL)
8288 /* There are multiple edges into the header from outside
8289 the loop so there is no pre-header block. */
8298 /* Add LOOP to the loop hierarchy tree where PREVLOOP was the loop
8299 previously added. The insertion algorithm assumes that the loops
8300 are added in the order found by a depth first search of the CFG. */
8303 flow_loop_tree_node_add (prevloop, loop)
8304 struct loop *prevloop;
8308 if (flow_loop_nested_p (prevloop, loop))
8310 prevloop->inner = loop;
8311 loop->outer = prevloop;
8315 while (prevloop->outer)
8317 if (flow_loop_nested_p (prevloop->outer, loop))
8319 prevloop->next = loop;
8320 loop->outer = prevloop->outer;
8323 prevloop = prevloop->outer;
8326 prevloop->next = loop;
8330 /* Build the loop hierarchy tree for LOOPS. */
8333 flow_loops_tree_build (loops)
8334 struct loops *loops;
8339 num_loops = loops->num;
8343 /* Root the loop hierarchy tree with the first loop found.
8344 Since we used a depth first search this should be the
8346 loops->tree = &loops->array[0];
8347 loops->tree->outer = loops->tree->inner = loops->tree->next = NULL;
8349 /* Add the remaining loops to the tree. */
8350 for (i = 1; i < num_loops; i++)
8351 flow_loop_tree_node_add (&loops->array[i - 1], &loops->array[i]);
8354 /* Helper function to compute loop nesting depth and enclosed loop level
8355 for the natural loop specified by LOOP at the loop depth DEPTH.
8356 Returns the loop level. */
8359 flow_loop_level_compute (loop, depth)
8369 /* Traverse loop tree assigning depth and computing level as the
8370 maximum level of all the inner loops of this loop. The loop
8371 level is equivalent to the height of the loop in the loop tree
8372 and corresponds to the number of enclosed loop levels (including
8374 for (inner = loop->inner; inner; inner = inner->next)
8378 ilevel = flow_loop_level_compute (inner, depth + 1) + 1;
8383 loop->level = level;
8384 loop->depth = depth;
8388 /* Compute the loop nesting depth and enclosed loop level for the loop
8389 hierarchy tree specfied by LOOPS. Return the maximum enclosed loop
8393 flow_loops_level_compute (loops)
8394 struct loops *loops;
8400 /* Traverse all the outer level loops. */
8401 for (loop = loops->tree; loop; loop = loop->next)
8403 level = flow_loop_level_compute (loop, 1);
8411 /* Scan a single natural loop specified by LOOP collecting information
8412 about it specified by FLAGS. */
8415 flow_loop_scan (loops, loop, flags)
8416 struct loops *loops;
8420 /* Determine prerequisites. */
8421 if ((flags & LOOP_EXITS_DOMS) && ! loop->exit_edges)
8422 flags |= LOOP_EXIT_EDGES;
8424 if (flags & LOOP_ENTRY_EDGES)
8426 /* Find edges which enter the loop header.
8427 Note that the entry edges should only
8428 enter the header of a natural loop. */
8430 = flow_loop_entry_edges_find (loop->header,
8432 &loop->entry_edges);
8435 if (flags & LOOP_EXIT_EDGES)
8437 /* Find edges which exit the loop. */
8439 = flow_loop_exit_edges_find (loop->nodes,
8443 if (flags & LOOP_EXITS_DOMS)
8447 /* Determine which loop nodes dominate all the exits
8449 loop->exits_doms = sbitmap_alloc (n_basic_blocks);
8450 sbitmap_copy (loop->exits_doms, loop->nodes);
8451 for (j = 0; j < loop->num_exits; j++)
8452 sbitmap_a_and_b (loop->exits_doms, loop->exits_doms,
8453 loops->cfg.dom[loop->exit_edges[j]->src->index]);
8455 /* The header of a natural loop must dominate
8457 if (! TEST_BIT (loop->exits_doms, loop->header->index))
8461 if (flags & LOOP_PRE_HEADER)
8463 /* Look to see if the loop has a pre-header node. */
8465 = flow_loop_pre_header_find (loop->header, loops->cfg.dom);
8467 /* Find the blocks within the extended basic block of
8468 the loop pre-header. */
8469 flow_loop_pre_header_scan (loop);
8475 /* Find all the natural loops in the function and save in LOOPS structure
8476 and recalculate loop_depth information in basic block structures.
8477 FLAGS controls which loop information is collected.
8478 Return the number of natural loops found. */
8481 flow_loops_find (loops, flags)
8482 struct loops *loops;
8494 /* This function cannot be repeatedly called with different
8495 flags to build up the loop information. The loop tree
8496 must always be built if this function is called. */
8497 if (! (flags & LOOP_TREE))
8500 memset (loops, 0, sizeof (*loops));
8502 /* Taking care of this degenerate case makes the rest of
8503 this code simpler. */
8504 if (n_basic_blocks == 0)
8510 /* Compute the dominators. */
8511 dom = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
8512 calculate_dominance_info (NULL, dom, CDI_DOMINATORS);
8514 /* Count the number of loop edges (back edges). This should be the
8515 same as the number of natural loops. */
8518 for (b = 0; b < n_basic_blocks; b++)
8522 header = BASIC_BLOCK (b);
8523 header->loop_depth = 0;
8525 for (e = header->pred; e; e = e->pred_next)
8527 basic_block latch = e->src;
8529 /* Look for back edges where a predecessor is dominated
8530 by this block. A natural loop has a single entry
8531 node (header) that dominates all the nodes in the
8532 loop. It also has single back edge to the header
8533 from a latch node. Note that multiple natural loops
8534 may share the same header. */
8535 if (b != header->index)
8538 if (latch != ENTRY_BLOCK_PTR && TEST_BIT (dom[latch->index], b))
8545 /* Compute depth first search order of the CFG so that outer
8546 natural loops will be found before inner natural loops. */
8547 dfs_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
8548 rc_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
8549 flow_depth_first_order_compute (dfs_order, rc_order);
8551 /* Save CFG derived information to avoid recomputing it. */
8552 loops->cfg.dom = dom;
8553 loops->cfg.dfs_order = dfs_order;
8554 loops->cfg.rc_order = rc_order;
8556 /* Allocate loop structures. */
8558 = (struct loop *) xcalloc (num_loops, sizeof (struct loop));
8560 headers = sbitmap_alloc (n_basic_blocks);
8561 sbitmap_zero (headers);
8563 loops->shared_headers = sbitmap_alloc (n_basic_blocks);
8564 sbitmap_zero (loops->shared_headers);
8566 /* Find and record information about all the natural loops
8569 for (b = 0; b < n_basic_blocks; b++)
8573 /* Search the nodes of the CFG in reverse completion order
8574 so that we can find outer loops first. */
8575 header = BASIC_BLOCK (rc_order[b]);
8577 /* Look for all the possible latch blocks for this header. */
8578 for (e = header->pred; e; e = e->pred_next)
8580 basic_block latch = e->src;
8582 /* Look for back edges where a predecessor is dominated
8583 by this block. A natural loop has a single entry
8584 node (header) that dominates all the nodes in the
8585 loop. It also has single back edge to the header
8586 from a latch node. Note that multiple natural loops
8587 may share the same header. */
8588 if (latch != ENTRY_BLOCK_PTR
8589 && TEST_BIT (dom[latch->index], header->index))
8593 loop = loops->array + num_loops;
8595 loop->header = header;
8596 loop->latch = latch;
8597 loop->num = num_loops;
8604 for (i = 0; i < num_loops; i++)
8606 struct loop *loop = &loops->array[i];
8608 /* Keep track of blocks that are loop headers so
8609 that we can tell which loops should be merged. */
8610 if (TEST_BIT (headers, loop->header->index))
8611 SET_BIT (loops->shared_headers, loop->header->index);
8612 SET_BIT (headers, loop->header->index);
8614 /* Find nodes contained within the loop. */
8615 loop->nodes = sbitmap_alloc (n_basic_blocks);
8617 = flow_loop_nodes_find (loop->header, loop->latch, loop->nodes);
8619 /* Compute first and last blocks within the loop.
8620 These are often the same as the loop header and
8621 loop latch respectively, but this is not always
8624 = BASIC_BLOCK (sbitmap_first_set_bit (loop->nodes));
8626 = BASIC_BLOCK (sbitmap_last_set_bit (loop->nodes));
8628 flow_loop_scan (loops, loop, flags);
8631 /* Natural loops with shared headers may either be disjoint or
8632 nested. Disjoint loops with shared headers cannot be inner
8633 loops and should be merged. For now just mark loops that share
8635 for (i = 0; i < num_loops; i++)
8636 if (TEST_BIT (loops->shared_headers, loops->array[i].header->index))
8637 loops->array[i].shared = 1;
8639 sbitmap_free (headers);
8642 loops->num = num_loops;
8644 /* Build the loop hierarchy tree. */
8645 flow_loops_tree_build (loops);
8647 /* Assign the loop nesting depth and enclosed loop level for each
8649 loops->levels = flow_loops_level_compute (loops);
8655 /* Update the information regarding the loops in the CFG
8656 specified by LOOPS. */
8658 flow_loops_update (loops, flags)
8659 struct loops *loops;
8662 /* One day we may want to update the current loop data. For now
8663 throw away the old stuff and rebuild what we need. */
8665 flow_loops_free (loops);
8667 return flow_loops_find (loops, flags);
8671 /* Return non-zero if edge E enters header of LOOP from outside of LOOP. */
8674 flow_loop_outside_edge_p (loop, e)
8675 const struct loop *loop;
8678 if (e->dest != loop->header)
8680 return (e->src == ENTRY_BLOCK_PTR)
8681 || ! TEST_BIT (loop->nodes, e->src->index);
8684 /* Clear LOG_LINKS fields of insns in a chain.
8685 Also clear the global_live_at_{start,end} fields of the basic block
8689 clear_log_links (insns)
8695 for (i = insns; i; i = NEXT_INSN (i))
8699 for (b = 0; b < n_basic_blocks; b++)
8701 basic_block bb = BASIC_BLOCK (b);
8703 bb->global_live_at_start = NULL;
8704 bb->global_live_at_end = NULL;
8707 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
8708 EXIT_BLOCK_PTR->global_live_at_start = NULL;
8711 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
8712 correspond to the hard registers, if any, set in that map. This
8713 could be done far more efficiently by having all sorts of special-cases
8714 with moving single words, but probably isn't worth the trouble. */
8717 reg_set_to_hard_reg_set (to, from)
8723 EXECUTE_IF_SET_IN_BITMAP
8726 if (i >= FIRST_PSEUDO_REGISTER)
8728 SET_HARD_REG_BIT (*to, i);
8732 /* Called once at intialization time. */
8737 static int initialized;
8741 gcc_obstack_init (&flow_obstack);
8742 flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);
8747 obstack_free (&flow_obstack, flow_firstobj);
8748 flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);