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 */
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 */
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 make_edges PARAMS ((rtx));
368 static void make_label_edge PARAMS ((sbitmap *, basic_block,
370 static void make_eh_edge PARAMS ((sbitmap *, basic_block, rtx));
372 static void commit_one_edge_insertion PARAMS ((edge));
374 static void delete_unreachable_blocks PARAMS ((void));
375 static int can_delete_note_p PARAMS ((rtx));
376 static void expunge_block PARAMS ((basic_block));
377 static int can_delete_label_p PARAMS ((rtx));
378 static int tail_recursion_label_p PARAMS ((rtx));
379 static int merge_blocks_move_predecessor_nojumps PARAMS ((basic_block,
381 static int merge_blocks_move_successor_nojumps PARAMS ((basic_block,
383 static int merge_blocks PARAMS ((edge,basic_block,basic_block));
384 static void try_merge_blocks PARAMS ((void));
385 static void tidy_fallthru_edges PARAMS ((void));
386 static int verify_wide_reg_1 PARAMS ((rtx *, void *));
387 static void verify_wide_reg PARAMS ((int, rtx, rtx));
388 static void verify_local_live_at_start PARAMS ((regset, basic_block));
389 static int noop_move_p PARAMS ((rtx));
390 static void delete_noop_moves PARAMS ((rtx));
391 static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
392 static void notice_stack_pointer_modification PARAMS ((rtx));
393 static void mark_reg PARAMS ((rtx, void *));
394 static void mark_regs_live_at_end PARAMS ((regset));
395 static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
396 static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
397 static void propagate_block_delete_insn PARAMS ((basic_block, rtx));
398 static rtx propagate_block_delete_libcall PARAMS ((basic_block, rtx, rtx));
399 static int insn_dead_p PARAMS ((struct propagate_block_info *,
401 static int libcall_dead_p PARAMS ((struct propagate_block_info *,
403 static void mark_set_regs PARAMS ((struct propagate_block_info *,
405 static void mark_set_1 PARAMS ((struct propagate_block_info *,
406 enum rtx_code, rtx, rtx,
408 #ifdef HAVE_conditional_execution
409 static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
411 static void free_reg_cond_life_info PARAMS ((splay_tree_value));
412 static int flush_reg_cond_reg_1 PARAMS ((splay_tree_node, void *));
413 static void flush_reg_cond_reg PARAMS ((struct propagate_block_info *,
415 static rtx elim_reg_cond PARAMS ((rtx, unsigned int));
416 static rtx ior_reg_cond PARAMS ((rtx, rtx, int));
417 static rtx not_reg_cond PARAMS ((rtx));
418 static rtx and_reg_cond PARAMS ((rtx, rtx, int));
421 static void attempt_auto_inc PARAMS ((struct propagate_block_info *,
422 rtx, rtx, rtx, rtx, rtx));
423 static void find_auto_inc PARAMS ((struct propagate_block_info *,
425 static int try_pre_increment_1 PARAMS ((struct propagate_block_info *,
427 static int try_pre_increment PARAMS ((rtx, rtx, HOST_WIDE_INT));
429 static void mark_used_reg PARAMS ((struct propagate_block_info *,
431 static void mark_used_regs PARAMS ((struct propagate_block_info *,
433 void dump_flow_info PARAMS ((FILE *));
434 void debug_flow_info PARAMS ((void));
435 static void print_rtl_and_abort_fcn PARAMS ((const char *, int,
439 static void invalidate_mems_from_autoinc PARAMS ((struct propagate_block_info *,
441 static void invalidate_mems_from_set PARAMS ((struct propagate_block_info *,
443 static void remove_fake_successors PARAMS ((basic_block));
444 static void flow_nodes_print PARAMS ((const char *, const sbitmap,
446 static void flow_edge_list_print PARAMS ((const char *, const edge *,
448 static void flow_loops_cfg_dump PARAMS ((const struct loops *,
450 static int flow_loop_nested_p PARAMS ((struct loop *,
452 static int flow_loop_entry_edges_find PARAMS ((basic_block, const sbitmap,
454 static int flow_loop_exit_edges_find PARAMS ((const sbitmap, edge **));
455 static int flow_loop_nodes_find PARAMS ((basic_block, basic_block, sbitmap));
456 static int flow_depth_first_order_compute PARAMS ((int *, int *));
457 static void flow_dfs_compute_reverse_init
458 PARAMS ((depth_first_search_ds));
459 static void flow_dfs_compute_reverse_add_bb
460 PARAMS ((depth_first_search_ds, basic_block));
461 static basic_block flow_dfs_compute_reverse_execute
462 PARAMS ((depth_first_search_ds));
463 static void flow_dfs_compute_reverse_finish
464 PARAMS ((depth_first_search_ds));
465 static void flow_loop_pre_header_scan PARAMS ((struct loop *));
466 static basic_block flow_loop_pre_header_find PARAMS ((basic_block,
468 static void flow_loop_tree_node_add PARAMS ((struct loop *, struct loop *));
469 static void flow_loops_tree_build PARAMS ((struct loops *));
470 static int flow_loop_level_compute PARAMS ((struct loop *, int));
471 static int flow_loops_level_compute PARAMS ((struct loops *));
472 static void allocate_bb_life_data PARAMS ((void));
473 static void find_sub_basic_blocks PARAMS ((basic_block));
475 /* Find basic blocks of the current function.
476 F is the first insn of the function and NREGS the number of register
480 find_basic_blocks (f, nregs, file)
482 int nregs ATTRIBUTE_UNUSED;
483 FILE *file ATTRIBUTE_UNUSED;
487 /* Flush out existing data. */
488 if (basic_block_info != NULL)
494 /* Clear bb->aux on all extant basic blocks. We'll use this as a
495 tag for reuse during create_basic_block, just in case some pass
496 copies around basic block notes improperly. */
497 for (i = 0; i < n_basic_blocks; ++i)
498 BASIC_BLOCK (i)->aux = NULL;
500 VARRAY_FREE (basic_block_info);
503 n_basic_blocks = count_basic_blocks (f);
505 /* Size the basic block table. The actual structures will be allocated
506 by find_basic_blocks_1, since we want to keep the structure pointers
507 stable across calls to find_basic_blocks. */
508 /* ??? This whole issue would be much simpler if we called find_basic_blocks
509 exactly once, and thereafter we don't have a single long chain of
510 instructions at all until close to the end of compilation when we
511 actually lay them out. */
513 VARRAY_BB_INIT (basic_block_info, n_basic_blocks, "basic_block_info");
515 find_basic_blocks_1 (f);
517 /* Record the block to which an insn belongs. */
518 /* ??? This should be done another way, by which (perhaps) a label is
519 tagged directly with the basic block that it starts. It is used for
520 more than that currently, but IMO that is the only valid use. */
522 max_uid = get_max_uid ();
524 /* Leave space for insns life_analysis makes in some cases for auto-inc.
525 These cases are rare, so we don't need too much space. */
526 max_uid += max_uid / 10;
529 compute_bb_for_insn (max_uid);
531 /* Discover the edges of our cfg. */
532 make_edges (label_value_list);
534 /* Do very simple cleanup now, for the benefit of code that runs between
535 here and cleanup_cfg, e.g. thread_prologue_and_epilogue_insns. */
536 tidy_fallthru_edges ();
538 mark_critical_edges ();
540 #ifdef ENABLE_CHECKING
546 check_function_return_warnings ()
548 if (warn_missing_noreturn
549 && !TREE_THIS_VOLATILE (cfun->decl)
550 && EXIT_BLOCK_PTR->pred == NULL
551 && (lang_missing_noreturn_ok_p
552 && !lang_missing_noreturn_ok_p (cfun->decl)))
553 warning ("function might be possible candidate for attribute `noreturn'");
555 /* If we have a path to EXIT, then we do return. */
556 if (TREE_THIS_VOLATILE (cfun->decl)
557 && EXIT_BLOCK_PTR->pred != NULL)
558 warning ("`noreturn' function does return");
560 /* If the clobber_return_insn appears in some basic block, then we
561 do reach the end without returning a value. */
562 else if (warn_return_type
563 && cfun->x_clobber_return_insn != NULL
564 && EXIT_BLOCK_PTR->pred != NULL)
566 int max_uid = get_max_uid ();
568 /* If clobber_return_insn was excised by jump1, then renumber_insns
569 can make max_uid smaller than the number still recorded in our rtx.
570 That's fine, since this is a quick way of verifying that the insn
571 is no longer in the chain. */
572 if (INSN_UID (cfun->x_clobber_return_insn) < max_uid)
574 /* Recompute insn->block mapping, since the initial mapping is
575 set before we delete unreachable blocks. */
576 compute_bb_for_insn (max_uid);
578 if (BLOCK_FOR_INSN (cfun->x_clobber_return_insn) != NULL)
579 warning ("control reaches end of non-void function");
584 /* Count the basic blocks of the function. */
587 count_basic_blocks (f)
591 register RTX_CODE prev_code;
592 register int count = 0;
593 int saw_abnormal_edge = 0;
595 prev_code = JUMP_INSN;
596 for (insn = f; insn; insn = NEXT_INSN (insn))
598 enum rtx_code code = GET_CODE (insn);
600 if (code == CODE_LABEL
601 || (GET_RTX_CLASS (code) == 'i'
602 && (prev_code == JUMP_INSN
603 || prev_code == BARRIER
604 || saw_abnormal_edge)))
606 saw_abnormal_edge = 0;
610 /* Record whether this insn created an edge. */
611 if (code == CALL_INSN)
615 /* If there is a nonlocal goto label and the specified
616 region number isn't -1, we have an edge. */
617 if (nonlocal_goto_handler_labels
618 && ((note = find_reg_note (insn, REG_EH_REGION, NULL_RTX)) == 0
619 || INTVAL (XEXP (note, 0)) >= 0))
620 saw_abnormal_edge = 1;
622 else if (can_throw_internal (insn))
623 saw_abnormal_edge = 1;
625 else if (flag_non_call_exceptions
627 && can_throw_internal (insn))
628 saw_abnormal_edge = 1;
634 /* The rest of the compiler works a bit smoother when we don't have to
635 check for the edge case of do-nothing functions with no basic blocks. */
638 emit_insn (gen_rtx_USE (VOIDmode, const0_rtx));
645 /* Scan a list of insns for labels referred to other than by jumps.
646 This is used to scan the alternatives of a call placeholder. */
648 find_label_refs (f, lvl)
654 for (insn = f; insn; insn = NEXT_INSN (insn))
655 if (INSN_P (insn) && GET_CODE (insn) != JUMP_INSN)
659 /* Make a list of all labels referred to other than by jumps
660 (which just don't have the REG_LABEL notes).
662 Make a special exception for labels followed by an ADDR*VEC,
663 as this would be a part of the tablejump setup code.
665 Make a special exception to registers loaded with label
666 values just before jump insns that use them. */
668 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
669 if (REG_NOTE_KIND (note) == REG_LABEL)
671 rtx lab = XEXP (note, 0), next;
673 if ((next = next_nonnote_insn (lab)) != NULL
674 && GET_CODE (next) == JUMP_INSN
675 && (GET_CODE (PATTERN (next)) == ADDR_VEC
676 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
678 else if (GET_CODE (lab) == NOTE)
680 else if (GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
681 && find_reg_note (NEXT_INSN (insn), REG_LABEL, lab))
684 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
691 /* Assume that someone emitted code with control flow instructions to the
692 basic block. Update the data structure. */
694 find_sub_basic_blocks (bb)
697 rtx first_insn = bb->head, insn;
699 edge succ_list = bb->succ;
700 rtx jump_insn = NULL_RTX;
704 basic_block first_bb = bb, last_bb;
707 if (GET_CODE (first_insn) == LABEL_REF)
708 first_insn = NEXT_INSN (first_insn);
709 first_insn = NEXT_INSN (first_insn);
713 /* Scan insn chain and try to find new basic block boundaries. */
716 enum rtx_code code = GET_CODE (insn);
720 /* We need some special care for those expressions. */
721 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
722 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
731 /* On code label, split current basic block. */
733 falltru = split_block (bb, PREV_INSN (insn));
738 remove_edge (falltru);
742 if (LABEL_ALTERNATE_NAME (insn))
743 make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0);
746 /* In case we've previously split insn on the JUMP_INSN, move the
747 block header to proper place. */
750 falltru = split_block (bb, PREV_INSN (insn));
760 insn = NEXT_INSN (insn);
762 /* Last basic block must end in the original BB end. */
766 /* Wire in the original edges for last basic block. */
769 bb->succ = succ_list;
771 succ_list->src = bb, succ_list = succ_list->succ_next;
774 bb->succ = succ_list;
776 /* Now re-scan and wire in all edges. This expect simple (conditional)
777 jumps at the end of each new basic blocks. */
779 for (i = first_bb->index; i < last_bb->index; i++)
781 bb = BASIC_BLOCK (i);
782 if (GET_CODE (bb->end) == JUMP_INSN)
784 mark_jump_label (PATTERN (bb->end), bb->end, 0, 0);
785 make_label_edge (NULL, bb, JUMP_LABEL (bb->end), 0);
787 insn = NEXT_INSN (insn);
791 /* Find all basic blocks of the function whose first insn is F.
793 Collect and return a list of labels whose addresses are taken. This
794 will be used in make_edges for use with computed gotos. */
797 find_basic_blocks_1 (f)
800 register rtx insn, next;
802 rtx bb_note = NULL_RTX;
808 /* We process the instructions in a slightly different way than we did
809 previously. This is so that we see a NOTE_BASIC_BLOCK after we have
810 closed out the previous block, so that it gets attached at the proper
811 place. Since this form should be equivalent to the previous,
812 count_basic_blocks continues to use the old form as a check. */
814 for (insn = f; insn; insn = next)
816 enum rtx_code code = GET_CODE (insn);
818 next = NEXT_INSN (insn);
824 int kind = NOTE_LINE_NUMBER (insn);
826 /* Look for basic block notes with which to keep the
827 basic_block_info pointers stable. Unthread the note now;
828 we'll put it back at the right place in create_basic_block.
829 Or not at all if we've already found a note in this block. */
830 if (kind == NOTE_INSN_BASIC_BLOCK)
832 if (bb_note == NULL_RTX)
835 next = flow_delete_insn (insn);
841 /* A basic block starts at a label. If we've closed one off due
842 to a barrier or some such, no need to do it again. */
843 if (head != NULL_RTX)
845 /* While we now have edge lists with which other portions of
846 the compiler might determine a call ending a basic block
847 does not imply an abnormal edge, it will be a bit before
848 everything can be updated. So continue to emit a noop at
849 the end of such a block. */
850 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
852 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
853 end = emit_insn_after (nop, end);
856 create_basic_block (i++, head, end, bb_note);
864 /* A basic block ends at a jump. */
865 if (head == NULL_RTX)
869 /* ??? Make a special check for table jumps. The way this
870 happens is truly and amazingly gross. We are about to
871 create a basic block that contains just a code label and
872 an addr*vec jump insn. Worse, an addr_diff_vec creates
873 its own natural loop.
875 Prevent this bit of brain damage, pasting things together
876 correctly in make_edges.
878 The correct solution involves emitting the table directly
879 on the tablejump instruction as a note, or JUMP_LABEL. */
881 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
882 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
890 goto new_bb_inclusive;
893 /* A basic block ends at a barrier. It may be that an unconditional
894 jump already closed the basic block -- no need to do it again. */
895 if (head == NULL_RTX)
898 /* While we now have edge lists with which other portions of the
899 compiler might determine a call ending a basic block does not
900 imply an abnormal edge, it will be a bit before everything can
901 be updated. So continue to emit a noop at the end of such a
903 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
905 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
906 end = emit_insn_after (nop, end);
908 goto new_bb_exclusive;
912 /* Record whether this call created an edge. */
913 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
914 int region = (note ? INTVAL (XEXP (note, 0)) : 0);
916 if (GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
918 /* Scan each of the alternatives for label refs. */
919 lvl = find_label_refs (XEXP (PATTERN (insn), 0), lvl);
920 lvl = find_label_refs (XEXP (PATTERN (insn), 1), lvl);
921 lvl = find_label_refs (XEXP (PATTERN (insn), 2), lvl);
922 /* Record its tail recursion label, if any. */
923 if (XEXP (PATTERN (insn), 3) != NULL_RTX)
924 trll = alloc_EXPR_LIST (0, XEXP (PATTERN (insn), 3), trll);
927 /* A basic block ends at a call that can either throw or
928 do a non-local goto. */
929 if ((nonlocal_goto_handler_labels && region >= 0)
930 || can_throw_internal (insn))
933 if (head == NULL_RTX)
938 create_basic_block (i++, head, end, bb_note);
939 head = end = NULL_RTX;
947 /* Non-call exceptions generate new blocks just like calls. */
948 if (flag_non_call_exceptions && can_throw_internal (insn))
949 goto new_bb_inclusive;
951 if (head == NULL_RTX)
960 if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
964 /* Make a list of all labels referred to other than by jumps.
966 Make a special exception for labels followed by an ADDR*VEC,
967 as this would be a part of the tablejump setup code.
969 Make a special exception to registers loaded with label
970 values just before jump insns that use them. */
972 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
973 if (REG_NOTE_KIND (note) == REG_LABEL)
975 rtx lab = XEXP (note, 0), next;
977 if ((next = next_nonnote_insn (lab)) != NULL
978 && GET_CODE (next) == JUMP_INSN
979 && (GET_CODE (PATTERN (next)) == ADDR_VEC
980 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
982 else if (GET_CODE (lab) == NOTE)
984 else if (GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
985 && find_reg_note (NEXT_INSN (insn), REG_LABEL, lab))
988 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
993 if (head != NULL_RTX)
994 create_basic_block (i++, head, end, bb_note);
996 flow_delete_insn (bb_note);
998 if (i != n_basic_blocks)
1001 label_value_list = lvl;
1002 tail_recursion_label_list = trll;
1005 /* Tidy the CFG by deleting unreachable code and whatnot. */
1010 delete_unreachable_blocks ();
1011 try_merge_blocks ();
1012 mark_critical_edges ();
1014 /* Kill the data we won't maintain. */
1015 free_EXPR_LIST_list (&label_value_list);
1016 free_EXPR_LIST_list (&tail_recursion_label_list);
1019 /* Create a new basic block consisting of the instructions between
1020 HEAD and END inclusive. Reuses the note and basic block struct
1021 in BB_NOTE, if any. */
1024 create_basic_block (index, head, end, bb_note)
1026 rtx head, end, bb_note;
1031 && ! RTX_INTEGRATED_P (bb_note)
1032 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
1035 /* If we found an existing note, thread it back onto the chain. */
1039 if (GET_CODE (head) == CODE_LABEL)
1043 after = PREV_INSN (head);
1047 if (after != bb_note && NEXT_INSN (after) != bb_note)
1048 reorder_insns (bb_note, bb_note, after);
1052 /* Otherwise we must create a note and a basic block structure.
1053 Since we allow basic block structs in rtl, give the struct
1054 the same lifetime by allocating it off the function obstack
1055 rather than using malloc. */
1057 bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*bb));
1058 memset (bb, 0, sizeof (*bb));
1060 if (GET_CODE (head) == CODE_LABEL)
1061 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
1064 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
1067 NOTE_BASIC_BLOCK (bb_note) = bb;
1070 /* Always include the bb note in the block. */
1071 if (NEXT_INSN (end) == bb_note)
1077 BASIC_BLOCK (index) = bb;
1079 /* Tag the block so that we know it has been used when considering
1080 other basic block notes. */
1084 /* Records the basic block struct in BB_FOR_INSN, for every instruction
1085 indexed by INSN_UID. MAX is the size of the array. */
1088 compute_bb_for_insn (max)
1093 if (basic_block_for_insn)
1094 VARRAY_FREE (basic_block_for_insn);
1095 VARRAY_BB_INIT (basic_block_for_insn, max, "basic_block_for_insn");
1097 for (i = 0; i < n_basic_blocks; ++i)
1099 basic_block bb = BASIC_BLOCK (i);
1106 int uid = INSN_UID (insn);
1108 VARRAY_BB (basic_block_for_insn, uid) = bb;
1111 insn = NEXT_INSN (insn);
1116 /* Free the memory associated with the edge structures. */
1124 for (i = 0; i < n_basic_blocks; ++i)
1126 basic_block bb = BASIC_BLOCK (i);
1128 for (e = bb->succ; e; e = n)
1138 for (e = ENTRY_BLOCK_PTR->succ; e; e = n)
1144 ENTRY_BLOCK_PTR->succ = 0;
1145 EXIT_BLOCK_PTR->pred = 0;
1150 /* Identify the edges between basic blocks.
1152 NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks
1153 that are otherwise unreachable may be reachable with a non-local goto.
1155 BB_EH_END is an array indexed by basic block number in which we record
1156 the list of exception regions active at the end of the basic block. */
1159 make_edges (label_value_list)
1160 rtx label_value_list;
1163 sbitmap *edge_cache = NULL;
1165 /* Assume no computed jump; revise as we create edges. */
1166 current_function_has_computed_jump = 0;
1168 /* Heavy use of computed goto in machine-generated code can lead to
1169 nearly fully-connected CFGs. In that case we spend a significant
1170 amount of time searching the edge lists for duplicates. */
1171 if (forced_labels || label_value_list)
1173 edge_cache = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
1174 sbitmap_vector_zero (edge_cache, n_basic_blocks);
1177 /* By nature of the way these get numbered, block 0 is always the entry. */
1178 make_edge (edge_cache, ENTRY_BLOCK_PTR, BASIC_BLOCK (0), EDGE_FALLTHRU);
1180 for (i = 0; i < n_basic_blocks; ++i)
1182 basic_block bb = BASIC_BLOCK (i);
1185 int force_fallthru = 0;
1187 if (GET_CODE (bb->head) == CODE_LABEL
1188 && LABEL_ALTERNATE_NAME (bb->head))
1189 make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0);
1191 /* Examine the last instruction of the block, and discover the
1192 ways we can leave the block. */
1195 code = GET_CODE (insn);
1198 if (code == JUMP_INSN)
1202 /* Recognize exception handling placeholders. */
1203 if (GET_CODE (PATTERN (insn)) == RESX)
1204 make_eh_edge (edge_cache, bb, insn);
1206 /* Recognize a non-local goto as a branch outside the
1207 current function. */
1208 else if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX))
1211 /* ??? Recognize a tablejump and do the right thing. */
1212 else if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1213 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1214 && GET_CODE (tmp) == JUMP_INSN
1215 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1216 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1221 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1222 vec = XVEC (PATTERN (tmp), 0);
1224 vec = XVEC (PATTERN (tmp), 1);
1226 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1227 make_label_edge (edge_cache, bb,
1228 XEXP (RTVEC_ELT (vec, j), 0), 0);
1230 /* Some targets (eg, ARM) emit a conditional jump that also
1231 contains the out-of-range target. Scan for these and
1232 add an edge if necessary. */
1233 if ((tmp = single_set (insn)) != NULL
1234 && SET_DEST (tmp) == pc_rtx
1235 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1236 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF)
1237 make_label_edge (edge_cache, bb,
1238 XEXP (XEXP (SET_SRC (tmp), 2), 0), 0);
1240 #ifdef CASE_DROPS_THROUGH
1241 /* Silly VAXen. The ADDR_VEC is going to be in the way of
1242 us naturally detecting fallthru into the next block. */
1247 /* If this is a computed jump, then mark it as reaching
1248 everything on the label_value_list and forced_labels list. */
1249 else if (computed_jump_p (insn))
1251 current_function_has_computed_jump = 1;
1253 for (x = label_value_list; x; x = XEXP (x, 1))
1254 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1256 for (x = forced_labels; x; x = XEXP (x, 1))
1257 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1260 /* Returns create an exit out. */
1261 else if (returnjump_p (insn))
1262 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, 0);
1264 /* Otherwise, we have a plain conditional or unconditional jump. */
1267 if (! JUMP_LABEL (insn))
1269 make_label_edge (edge_cache, bb, JUMP_LABEL (insn), 0);
1273 /* If this is a sibling call insn, then this is in effect a
1274 combined call and return, and so we need an edge to the
1275 exit block. No need to worry about EH edges, since we
1276 wouldn't have created the sibling call in the first place. */
1278 if (code == CALL_INSN && SIBLING_CALL_P (insn))
1279 make_edge (edge_cache, bb, EXIT_BLOCK_PTR,
1280 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1282 /* If this is a CALL_INSN, then mark it as reaching the active EH
1283 handler for this CALL_INSN. If we're handling non-call
1284 exceptions then any insn can reach any of the active handlers.
1286 Also mark the CALL_INSN as reaching any nonlocal goto handler. */
1288 else if (code == CALL_INSN || flag_non_call_exceptions)
1290 /* Add any appropriate EH edges. */
1291 make_eh_edge (edge_cache, bb, insn);
1293 if (code == CALL_INSN && nonlocal_goto_handler_labels)
1295 /* ??? This could be made smarter: in some cases it's possible
1296 to tell that certain calls will not do a nonlocal goto.
1298 For example, if the nested functions that do the nonlocal
1299 gotos do not have their addresses taken, then only calls to
1300 those functions or to other nested functions that use them
1301 could possibly do nonlocal gotos. */
1302 /* We do know that a REG_EH_REGION note with a value less
1303 than 0 is guaranteed not to perform a non-local goto. */
1304 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
1305 if (!note || INTVAL (XEXP (note, 0)) >= 0)
1306 for (x = nonlocal_goto_handler_labels; x; x = XEXP (x, 1))
1307 make_label_edge (edge_cache, bb, XEXP (x, 0),
1308 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1312 /* Find out if we can drop through to the next block. */
1313 insn = next_nonnote_insn (insn);
1314 if (!insn || (i + 1 == n_basic_blocks && force_fallthru))
1315 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU);
1316 else if (i + 1 < n_basic_blocks)
1318 rtx tmp = BLOCK_HEAD (i + 1);
1319 if (GET_CODE (tmp) == NOTE)
1320 tmp = next_nonnote_insn (tmp);
1321 if (force_fallthru || insn == tmp)
1322 make_edge (edge_cache, bb, BASIC_BLOCK (i + 1), EDGE_FALLTHRU);
1327 sbitmap_vector_free (edge_cache);
1330 /* Create an edge between two basic blocks. FLAGS are auxiliary information
1331 about the edge that is accumulated between calls. */
1334 make_edge (edge_cache, src, dst, flags)
1335 sbitmap *edge_cache;
1336 basic_block src, dst;
1342 /* Don't bother with edge cache for ENTRY or EXIT; there aren't that
1343 many edges to them, and we didn't allocate memory for it. */
1344 use_edge_cache = (edge_cache
1345 && src != ENTRY_BLOCK_PTR
1346 && dst != EXIT_BLOCK_PTR);
1348 /* Make sure we don't add duplicate edges. */
1349 switch (use_edge_cache)
1352 /* Quick test for non-existance of the edge. */
1353 if (! TEST_BIT (edge_cache[src->index], dst->index))
1356 /* The edge exists; early exit if no work to do. */
1362 for (e = src->succ; e; e = e->succ_next)
1371 e = (edge) xcalloc (1, sizeof (*e));
1374 e->succ_next = src->succ;
1375 e->pred_next = dst->pred;
1384 SET_BIT (edge_cache[src->index], dst->index);
1387 /* Create an edge from a basic block to a label. */
1390 make_label_edge (edge_cache, src, label, flags)
1391 sbitmap *edge_cache;
1396 if (GET_CODE (label) != CODE_LABEL)
1399 /* If the label was never emitted, this insn is junk, but avoid a
1400 crash trying to refer to BLOCK_FOR_INSN (label). This can happen
1401 as a result of a syntax error and a diagnostic has already been
1404 if (INSN_UID (label) == 0)
1407 make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags);
1410 /* Create the edges generated by INSN in REGION. */
1413 make_eh_edge (edge_cache, src, insn)
1414 sbitmap *edge_cache;
1418 int is_call = (GET_CODE (insn) == CALL_INSN ? EDGE_ABNORMAL_CALL : 0);
1421 handlers = reachable_handlers (insn);
1423 for (i = handlers; i; i = XEXP (i, 1))
1424 make_label_edge (edge_cache, src, XEXP (i, 0),
1425 EDGE_ABNORMAL | EDGE_EH | is_call);
1427 free_INSN_LIST_list (&handlers);
1430 /* Identify critical edges and set the bits appropriately. */
1433 mark_critical_edges ()
1435 int i, n = n_basic_blocks;
1438 /* We begin with the entry block. This is not terribly important now,
1439 but could be if a front end (Fortran) implemented alternate entry
1441 bb = ENTRY_BLOCK_PTR;
1448 /* (1) Critical edges must have a source with multiple successors. */
1449 if (bb->succ && bb->succ->succ_next)
1451 for (e = bb->succ; e; e = e->succ_next)
1453 /* (2) Critical edges must have a destination with multiple
1454 predecessors. Note that we know there is at least one
1455 predecessor -- the edge we followed to get here. */
1456 if (e->dest->pred->pred_next)
1457 e->flags |= EDGE_CRITICAL;
1459 e->flags &= ~EDGE_CRITICAL;
1464 for (e = bb->succ; e; e = e->succ_next)
1465 e->flags &= ~EDGE_CRITICAL;
1470 bb = BASIC_BLOCK (i);
1474 /* Split a block BB after insn INSN creating a new fallthru edge.
1475 Return the new edge. Note that to keep other parts of the compiler happy,
1476 this function renumbers all the basic blocks so that the new
1477 one has a number one greater than the block split. */
1480 split_block (bb, insn)
1490 /* There is no point splitting the block after its end. */
1491 if (bb->end == insn)
1494 /* Create the new structures. */
1495 new_bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*new_bb));
1496 new_edge = (edge) xcalloc (1, sizeof (*new_edge));
1499 memset (new_bb, 0, sizeof (*new_bb));
1501 new_bb->head = NEXT_INSN (insn);
1502 new_bb->end = bb->end;
1505 new_bb->succ = bb->succ;
1506 bb->succ = new_edge;
1507 new_bb->pred = new_edge;
1508 new_bb->count = bb->count;
1509 new_bb->frequency = bb->frequency;
1510 new_bb->loop_depth = bb->loop_depth;
1513 new_edge->dest = new_bb;
1514 new_edge->flags = EDGE_FALLTHRU;
1515 new_edge->probability = REG_BR_PROB_BASE;
1516 new_edge->count = bb->count;
1518 /* Redirect the src of the successor edges of bb to point to new_bb. */
1519 for (e = new_bb->succ; e; e = e->succ_next)
1522 /* Place the new block just after the block being split. */
1523 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
1525 /* Some parts of the compiler expect blocks to be number in
1526 sequential order so insert the new block immediately after the
1527 block being split.. */
1529 for (i = n_basic_blocks - 1; i > j + 1; --i)
1531 basic_block tmp = BASIC_BLOCK (i - 1);
1532 BASIC_BLOCK (i) = tmp;
1536 BASIC_BLOCK (i) = new_bb;
1539 if (GET_CODE (new_bb->head) == CODE_LABEL)
1541 /* Create the basic block note. */
1542 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK,
1544 NOTE_BASIC_BLOCK (bb_note) = new_bb;
1548 /* Create the basic block note. */
1549 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
1551 NOTE_BASIC_BLOCK (bb_note) = new_bb;
1552 new_bb->head = bb_note;
1555 update_bb_for_insn (new_bb);
1557 if (bb->global_live_at_start)
1559 new_bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1560 new_bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1561 COPY_REG_SET (new_bb->global_live_at_end, bb->global_live_at_end);
1563 /* We now have to calculate which registers are live at the end
1564 of the split basic block and at the start of the new basic
1565 block. Start with those registers that are known to be live
1566 at the end of the original basic block and get
1567 propagate_block to determine which registers are live. */
1568 COPY_REG_SET (new_bb->global_live_at_start, bb->global_live_at_end);
1569 propagate_block (new_bb, new_bb->global_live_at_start, NULL, NULL, 0);
1570 COPY_REG_SET (bb->global_live_at_end,
1571 new_bb->global_live_at_start);
1578 /* Split a (typically critical) edge. Return the new block.
1579 Abort on abnormal edges.
1581 ??? The code generally expects to be called on critical edges.
1582 The case of a block ending in an unconditional jump to a
1583 block with multiple predecessors is not handled optimally. */
1586 split_edge (edge_in)
1589 basic_block old_pred, bb, old_succ;
1594 /* Abnormal edges cannot be split. */
1595 if ((edge_in->flags & EDGE_ABNORMAL) != 0)
1598 old_pred = edge_in->src;
1599 old_succ = edge_in->dest;
1601 /* Remove the existing edge from the destination's pred list. */
1604 for (pp = &old_succ->pred; *pp != edge_in; pp = &(*pp)->pred_next)
1606 *pp = edge_in->pred_next;
1607 edge_in->pred_next = NULL;
1610 /* Create the new structures. */
1611 bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*bb));
1612 edge_out = (edge) xcalloc (1, sizeof (*edge_out));
1615 memset (bb, 0, sizeof (*bb));
1617 /* ??? This info is likely going to be out of date very soon. */
1618 if (old_succ->global_live_at_start)
1620 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1621 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1622 COPY_REG_SET (bb->global_live_at_start, old_succ->global_live_at_start);
1623 COPY_REG_SET (bb->global_live_at_end, old_succ->global_live_at_start);
1628 bb->succ = edge_out;
1629 bb->count = edge_in->count;
1630 bb->frequency = (edge_in->probability * edge_in->src->frequency
1631 / REG_BR_PROB_BASE);
1634 edge_in->flags &= ~EDGE_CRITICAL;
1636 edge_out->pred_next = old_succ->pred;
1637 edge_out->succ_next = NULL;
1639 edge_out->dest = old_succ;
1640 edge_out->flags = EDGE_FALLTHRU;
1641 edge_out->probability = REG_BR_PROB_BASE;
1642 edge_out->count = edge_in->count;
1644 old_succ->pred = edge_out;
1646 /* Tricky case -- if there existed a fallthru into the successor
1647 (and we're not it) we must add a new unconditional jump around
1648 the new block we're actually interested in.
1650 Further, if that edge is critical, this means a second new basic
1651 block must be created to hold it. In order to simplify correct
1652 insn placement, do this before we touch the existing basic block
1653 ordering for the block we were really wanting. */
1654 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1657 for (e = edge_out->pred_next; e; e = e->pred_next)
1658 if (e->flags & EDGE_FALLTHRU)
1663 basic_block jump_block;
1666 if ((e->flags & EDGE_CRITICAL) == 0
1667 && e->src != ENTRY_BLOCK_PTR)
1669 /* Non critical -- we can simply add a jump to the end
1670 of the existing predecessor. */
1671 jump_block = e->src;
1675 /* We need a new block to hold the jump. The simplest
1676 way to do the bulk of the work here is to recursively
1678 jump_block = split_edge (e);
1679 e = jump_block->succ;
1682 /* Now add the jump insn ... */
1683 pos = emit_jump_insn_after (gen_jump (old_succ->head),
1685 jump_block->end = pos;
1686 if (basic_block_for_insn)
1687 set_block_for_insn (pos, jump_block);
1688 emit_barrier_after (pos);
1690 /* ... let jump know that label is in use, ... */
1691 JUMP_LABEL (pos) = old_succ->head;
1692 ++LABEL_NUSES (old_succ->head);
1694 /* ... and clear fallthru on the outgoing edge. */
1695 e->flags &= ~EDGE_FALLTHRU;
1697 /* Continue splitting the interesting edge. */
1701 /* Place the new block just in front of the successor. */
1702 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
1703 if (old_succ == EXIT_BLOCK_PTR)
1704 j = n_basic_blocks - 1;
1706 j = old_succ->index;
1707 for (i = n_basic_blocks - 1; i > j; --i)
1709 basic_block tmp = BASIC_BLOCK (i - 1);
1710 BASIC_BLOCK (i) = tmp;
1713 BASIC_BLOCK (i) = bb;
1716 /* Create the basic block note.
1718 Where we place the note can have a noticable impact on the generated
1719 code. Consider this cfg:
1729 If we need to insert an insn on the edge from block 0 to block 1,
1730 we want to ensure the instructions we insert are outside of any
1731 loop notes that physically sit between block 0 and block 1. Otherwise
1732 we confuse the loop optimizer into thinking the loop is a phony. */
1733 if (old_succ != EXIT_BLOCK_PTR
1734 && PREV_INSN (old_succ->head)
1735 && GET_CODE (PREV_INSN (old_succ->head)) == NOTE
1736 && NOTE_LINE_NUMBER (PREV_INSN (old_succ->head)) == NOTE_INSN_LOOP_BEG)
1737 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
1738 PREV_INSN (old_succ->head));
1739 else if (old_succ != EXIT_BLOCK_PTR)
1740 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, old_succ->head);
1742 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
1743 NOTE_BASIC_BLOCK (bb_note) = bb;
1744 bb->head = bb->end = bb_note;
1746 /* Not quite simple -- for non-fallthru edges, we must adjust the
1747 predecessor's jump instruction to target our new block. */
1748 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1750 rtx tmp, insn = old_pred->end;
1751 rtx old_label = old_succ->head;
1752 rtx new_label = gen_label_rtx ();
1754 if (GET_CODE (insn) != JUMP_INSN)
1757 /* ??? Recognize a tablejump and adjust all matching cases. */
1758 if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1759 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1760 && GET_CODE (tmp) == JUMP_INSN
1761 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1762 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1767 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1768 vec = XVEC (PATTERN (tmp), 0);
1770 vec = XVEC (PATTERN (tmp), 1);
1772 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1773 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
1775 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (VOIDmode, new_label);
1776 --LABEL_NUSES (old_label);
1777 ++LABEL_NUSES (new_label);
1780 /* Handle casesi dispatch insns */
1781 if ((tmp = single_set (insn)) != NULL
1782 && SET_DEST (tmp) == pc_rtx
1783 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1784 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
1785 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
1787 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (VOIDmode,
1789 --LABEL_NUSES (old_label);
1790 ++LABEL_NUSES (new_label);
1795 /* This would have indicated an abnormal edge. */
1796 if (computed_jump_p (insn))
1799 /* A return instruction can't be redirected. */
1800 if (returnjump_p (insn))
1803 /* If the insn doesn't go where we think, we're confused. */
1804 if (JUMP_LABEL (insn) != old_label)
1807 redirect_jump (insn, new_label, 0);
1810 emit_label_before (new_label, bb_note);
1811 bb->head = new_label;
1817 /* Queue instructions for insertion on an edge between two basic blocks.
1818 The new instructions and basic blocks (if any) will not appear in the
1819 CFG until commit_edge_insertions is called. */
1822 insert_insn_on_edge (pattern, e)
1826 /* We cannot insert instructions on an abnormal critical edge.
1827 It will be easier to find the culprit if we die now. */
1828 if ((e->flags & (EDGE_ABNORMAL|EDGE_CRITICAL))
1829 == (EDGE_ABNORMAL|EDGE_CRITICAL))
1832 if (e->insns == NULL_RTX)
1835 push_to_sequence (e->insns);
1837 emit_insn (pattern);
1839 e->insns = get_insns ();
1843 /* Update the CFG for the instructions queued on edge E. */
1846 commit_one_edge_insertion (e)
1849 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
1852 /* Pull the insns off the edge now since the edge might go away. */
1854 e->insns = NULL_RTX;
1856 /* Figure out where to put these things. If the destination has
1857 one predecessor, insert there. Except for the exit block. */
1858 if (e->dest->pred->pred_next == NULL
1859 && e->dest != EXIT_BLOCK_PTR)
1863 /* Get the location correct wrt a code label, and "nice" wrt
1864 a basic block note, and before everything else. */
1866 if (GET_CODE (tmp) == CODE_LABEL)
1867 tmp = NEXT_INSN (tmp);
1868 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
1869 tmp = NEXT_INSN (tmp);
1870 if (tmp == bb->head)
1873 after = PREV_INSN (tmp);
1876 /* If the source has one successor and the edge is not abnormal,
1877 insert there. Except for the entry block. */
1878 else if ((e->flags & EDGE_ABNORMAL) == 0
1879 && e->src->succ->succ_next == NULL
1880 && e->src != ENTRY_BLOCK_PTR)
1883 /* It is possible to have a non-simple jump here. Consider a target
1884 where some forms of unconditional jumps clobber a register. This
1885 happens on the fr30 for example.
1887 We know this block has a single successor, so we can just emit
1888 the queued insns before the jump. */
1889 if (GET_CODE (bb->end) == JUMP_INSN)
1895 /* We'd better be fallthru, or we've lost track of what's what. */
1896 if ((e->flags & EDGE_FALLTHRU) == 0)
1903 /* Otherwise we must split the edge. */
1906 bb = split_edge (e);
1910 /* Now that we've found the spot, do the insertion. */
1912 /* Set the new block number for these insns, if structure is allocated. */
1913 if (basic_block_for_insn)
1916 for (i = insns; i != NULL_RTX; i = NEXT_INSN (i))
1917 set_block_for_insn (i, bb);
1922 emit_insns_before (insns, before);
1923 if (before == bb->head)
1926 last = prev_nonnote_insn (before);
1930 last = emit_insns_after (insns, after);
1931 if (after == bb->end)
1935 if (returnjump_p (last))
1937 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1938 This is not currently a problem because this only happens
1939 for the (single) epilogue, which already has a fallthru edge
1943 if (e->dest != EXIT_BLOCK_PTR
1944 || e->succ_next != NULL
1945 || (e->flags & EDGE_FALLTHRU) == 0)
1947 e->flags &= ~EDGE_FALLTHRU;
1949 emit_barrier_after (last);
1953 flow_delete_insn (before);
1955 else if (GET_CODE (last) == JUMP_INSN)
1957 find_sub_basic_blocks (bb);
1960 /* Update the CFG for all queued instructions. */
1963 commit_edge_insertions ()
1968 #ifdef ENABLE_CHECKING
1969 verify_flow_info ();
1973 bb = ENTRY_BLOCK_PTR;
1978 for (e = bb->succ; e; e = next)
1980 next = e->succ_next;
1982 commit_one_edge_insertion (e);
1985 if (++i >= n_basic_blocks)
1987 bb = BASIC_BLOCK (i);
1991 /* Add fake edges to the function exit for any non constant calls in
1992 the bitmap of blocks specified by BLOCKS or to the whole CFG if
1993 BLOCKS is zero. Return the nuber of blocks that were split. */
1996 flow_call_edges_add (blocks)
2000 int blocks_split = 0;
2004 /* Map bb indicies into basic block pointers since split_block
2005 will renumber the basic blocks. */
2007 bbs = xmalloc (n_basic_blocks * sizeof (*bbs));
2011 for (i = 0; i < n_basic_blocks; i++)
2012 bbs[bb_num++] = BASIC_BLOCK (i);
2016 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
2018 bbs[bb_num++] = BASIC_BLOCK (i);
2023 /* Now add fake edges to the function exit for any non constant
2024 calls since there is no way that we can determine if they will
2027 for (i = 0; i < bb_num; i++)
2029 basic_block bb = bbs[i];
2033 for (insn = bb->end; ; insn = prev_insn)
2035 prev_insn = PREV_INSN (insn);
2036 if (GET_CODE (insn) == CALL_INSN && ! CONST_CALL_P (insn))
2040 /* Note that the following may create a new basic block
2041 and renumber the existing basic blocks. */
2042 e = split_block (bb, insn);
2046 make_edge (NULL, bb, EXIT_BLOCK_PTR, EDGE_FAKE);
2048 if (insn == bb->head)
2054 verify_flow_info ();
2057 return blocks_split;
2060 /* Find unreachable blocks. An unreachable block will have NULL in
2061 block->aux, a non-NULL value indicates the block is reachable. */
2064 find_unreachable_blocks ()
2068 basic_block *tos, *worklist;
2071 tos = worklist = (basic_block *) xmalloc (sizeof (basic_block) * n);
2073 /* Use basic_block->aux as a marker. Clear them all. */
2075 for (i = 0; i < n; ++i)
2076 BASIC_BLOCK (i)->aux = NULL;
2078 /* Add our starting points to the worklist. Almost always there will
2079 be only one. It isn't inconcievable that we might one day directly
2080 support Fortran alternate entry points. */
2082 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
2086 /* Mark the block with a handy non-null value. */
2090 /* Iterate: find everything reachable from what we've already seen. */
2092 while (tos != worklist)
2094 basic_block b = *--tos;
2096 for (e = b->succ; e; e = e->succ_next)
2107 /* Delete all unreachable basic blocks. */
2109 delete_unreachable_blocks ()
2113 find_unreachable_blocks ();
2115 /* Delete all unreachable basic blocks. Count down so that we
2116 don't interfere with the block renumbering that happens in
2117 flow_delete_block. */
2119 for (i = n_basic_blocks - 1; i >= 0; --i)
2121 basic_block b = BASIC_BLOCK (i);
2124 /* This block was found. Tidy up the mark. */
2127 flow_delete_block (b);
2130 tidy_fallthru_edges ();
2133 /* Return true if NOTE is not one of the ones that must be kept paired,
2134 so that we may simply delete them. */
2137 can_delete_note_p (note)
2140 return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED
2141 || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK);
2144 /* Unlink a chain of insns between START and FINISH, leaving notes
2145 that must be paired. */
2148 flow_delete_insn_chain (start, finish)
2151 /* Unchain the insns one by one. It would be quicker to delete all
2152 of these with a single unchaining, rather than one at a time, but
2153 we need to keep the NOTE's. */
2159 next = NEXT_INSN (start);
2160 if (GET_CODE (start) == NOTE && !can_delete_note_p (start))
2162 else if (GET_CODE (start) == CODE_LABEL
2163 && ! can_delete_label_p (start))
2165 const char *name = LABEL_NAME (start);
2166 PUT_CODE (start, NOTE);
2167 NOTE_LINE_NUMBER (start) = NOTE_INSN_DELETED_LABEL;
2168 NOTE_SOURCE_FILE (start) = name;
2171 next = flow_delete_insn (start);
2173 if (start == finish)
2179 /* Delete the insns in a (non-live) block. We physically delete every
2180 non-deleted-note insn, and update the flow graph appropriately.
2182 Return nonzero if we deleted an exception handler. */
2184 /* ??? Preserving all such notes strikes me as wrong. It would be nice
2185 to post-process the stream to remove empty blocks, loops, ranges, etc. */
2188 flow_delete_block (b)
2191 int deleted_handler = 0;
2194 /* If the head of this block is a CODE_LABEL, then it might be the
2195 label for an exception handler which can't be reached.
2197 We need to remove the label from the exception_handler_label list
2198 and remove the associated NOTE_INSN_EH_REGION_BEG and
2199 NOTE_INSN_EH_REGION_END notes. */
2203 never_reached_warning (insn);
2205 if (GET_CODE (insn) == CODE_LABEL)
2206 maybe_remove_eh_handler (insn);
2208 /* Include any jump table following the basic block. */
2210 if (GET_CODE (end) == JUMP_INSN
2211 && (tmp = JUMP_LABEL (end)) != NULL_RTX
2212 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
2213 && GET_CODE (tmp) == JUMP_INSN
2214 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
2215 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
2218 /* Include any barrier that may follow the basic block. */
2219 tmp = next_nonnote_insn (end);
2220 if (tmp && GET_CODE (tmp) == BARRIER)
2223 /* Selectively delete the entire chain. */
2224 flow_delete_insn_chain (insn, end);
2226 /* Remove the edges into and out of this block. Note that there may
2227 indeed be edges in, if we are removing an unreachable loop. */
2231 for (e = b->pred; e; e = next)
2233 for (q = &e->src->succ; *q != e; q = &(*q)->succ_next)
2236 next = e->pred_next;
2240 for (e = b->succ; e; e = next)
2242 for (q = &e->dest->pred; *q != e; q = &(*q)->pred_next)
2245 next = e->succ_next;
2254 /* Remove the basic block from the array, and compact behind it. */
2257 return deleted_handler;
2260 /* Remove block B from the basic block array and compact behind it. */
2266 int i, n = n_basic_blocks;
2268 for (i = b->index; i + 1 < n; ++i)
2270 basic_block x = BASIC_BLOCK (i + 1);
2271 BASIC_BLOCK (i) = x;
2275 basic_block_info->num_elements--;
2279 /* Delete INSN by patching it out. Return the next insn. */
2282 flow_delete_insn (insn)
2285 rtx prev = PREV_INSN (insn);
2286 rtx next = NEXT_INSN (insn);
2289 PREV_INSN (insn) = NULL_RTX;
2290 NEXT_INSN (insn) = NULL_RTX;
2291 INSN_DELETED_P (insn) = 1;
2294 NEXT_INSN (prev) = next;
2296 PREV_INSN (next) = prev;
2298 set_last_insn (prev);
2300 if (GET_CODE (insn) == CODE_LABEL)
2301 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2303 /* If deleting a jump, decrement the use count of the label. Deleting
2304 the label itself should happen in the normal course of block merging. */
2305 if (GET_CODE (insn) == JUMP_INSN
2306 && JUMP_LABEL (insn)
2307 && GET_CODE (JUMP_LABEL (insn)) == CODE_LABEL)
2308 LABEL_NUSES (JUMP_LABEL (insn))--;
2310 /* Also if deleting an insn that references a label. */
2311 else if ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX
2312 && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
2313 LABEL_NUSES (XEXP (note, 0))--;
2318 /* True if a given label can be deleted. */
2321 can_delete_label_p (label)
2326 if (LABEL_PRESERVE_P (label))
2329 for (x = forced_labels; x; x = XEXP (x, 1))
2330 if (label == XEXP (x, 0))
2332 for (x = label_value_list; x; x = XEXP (x, 1))
2333 if (label == XEXP (x, 0))
2335 for (x = exception_handler_labels; x; x = XEXP (x, 1))
2336 if (label == XEXP (x, 0))
2339 /* User declared labels must be preserved. */
2340 if (LABEL_NAME (label) != 0)
2347 tail_recursion_label_p (label)
2352 for (x = tail_recursion_label_list; x; x = XEXP (x, 1))
2353 if (label == XEXP (x, 0))
2359 /* Blocks A and B are to be merged into a single block A. The insns
2360 are already contiguous, hence `nomove'. */
2363 merge_blocks_nomove (a, b)
2367 rtx b_head, b_end, a_end;
2368 rtx del_first = NULL_RTX, del_last = NULL_RTX;
2371 /* If there was a CODE_LABEL beginning B, delete it. */
2374 if (GET_CODE (b_head) == CODE_LABEL)
2376 /* Detect basic blocks with nothing but a label. This can happen
2377 in particular at the end of a function. */
2378 if (b_head == b_end)
2380 del_first = del_last = b_head;
2381 b_head = NEXT_INSN (b_head);
2384 /* Delete the basic block note. */
2385 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
2387 if (b_head == b_end)
2392 b_head = NEXT_INSN (b_head);
2395 /* If there was a jump out of A, delete it. */
2397 if (GET_CODE (a_end) == JUMP_INSN)
2401 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
2402 if (GET_CODE (prev) != NOTE
2403 || NOTE_LINE_NUMBER (prev) == NOTE_INSN_BASIC_BLOCK
2410 /* If this was a conditional jump, we need to also delete
2411 the insn that set cc0. */
2412 if (prev && sets_cc0_p (prev))
2415 prev = prev_nonnote_insn (prev);
2424 else if (GET_CODE (NEXT_INSN (a_end)) == BARRIER)
2425 del_first = NEXT_INSN (a_end);
2427 /* Delete everything marked above as well as crap that might be
2428 hanging out between the two blocks. */
2429 flow_delete_insn_chain (del_first, del_last);
2431 /* Normally there should only be one successor of A and that is B, but
2432 partway though the merge of blocks for conditional_execution we'll
2433 be merging a TEST block with THEN and ELSE successors. Free the
2434 whole lot of them and hope the caller knows what they're doing. */
2436 remove_edge (a->succ);
2438 /* Adjust the edges out of B for the new owner. */
2439 for (e = b->succ; e; e = e->succ_next)
2443 /* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */
2444 b->pred = b->succ = NULL;
2446 /* Reassociate the insns of B with A. */
2449 if (basic_block_for_insn)
2451 BLOCK_FOR_INSN (b_head) = a;
2452 while (b_head != b_end)
2454 b_head = NEXT_INSN (b_head);
2455 BLOCK_FOR_INSN (b_head) = a;
2465 /* Blocks A and B are to be merged into a single block. A has no incoming
2466 fallthru edge, so it can be moved before B without adding or modifying
2467 any jumps (aside from the jump from A to B). */
2470 merge_blocks_move_predecessor_nojumps (a, b)
2473 rtx start, end, barrier;
2479 barrier = next_nonnote_insn (end);
2480 if (GET_CODE (barrier) != BARRIER)
2482 flow_delete_insn (barrier);
2484 /* Move block and loop notes out of the chain so that we do not
2485 disturb their order.
2487 ??? A better solution would be to squeeze out all the non-nested notes
2488 and adjust the block trees appropriately. Even better would be to have
2489 a tighter connection between block trees and rtl so that this is not
2491 start = squeeze_notes (start, end);
2493 /* Scramble the insn chain. */
2494 if (end != PREV_INSN (b->head))
2495 reorder_insns (start, end, PREV_INSN (b->head));
2499 fprintf (rtl_dump_file, "Moved block %d before %d and merged.\n",
2500 a->index, b->index);
2503 /* Swap the records for the two blocks around. Although we are deleting B,
2504 A is now where B was and we want to compact the BB array from where
2506 BASIC_BLOCK (a->index) = b;
2507 BASIC_BLOCK (b->index) = a;
2509 a->index = b->index;
2512 /* Now blocks A and B are contiguous. Merge them. */
2513 merge_blocks_nomove (a, b);
2518 /* Blocks A and B are to be merged into a single block. B has no outgoing
2519 fallthru edge, so it can be moved after A without adding or modifying
2520 any jumps (aside from the jump from A to B). */
2523 merge_blocks_move_successor_nojumps (a, b)
2526 rtx start, end, barrier;
2530 barrier = NEXT_INSN (end);
2532 /* Recognize a jump table following block B. */
2533 if (GET_CODE (barrier) == CODE_LABEL
2534 && NEXT_INSN (barrier)
2535 && GET_CODE (NEXT_INSN (barrier)) == JUMP_INSN
2536 && (GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_VEC
2537 || GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_DIFF_VEC))
2539 end = NEXT_INSN (barrier);
2540 barrier = NEXT_INSN (end);
2543 /* There had better have been a barrier there. Delete it. */
2544 if (GET_CODE (barrier) != BARRIER)
2546 flow_delete_insn (barrier);
2548 /* Move block and loop notes out of the chain so that we do not
2549 disturb their order.
2551 ??? A better solution would be to squeeze out all the non-nested notes
2552 and adjust the block trees appropriately. Even better would be to have
2553 a tighter connection between block trees and rtl so that this is not
2555 start = squeeze_notes (start, end);
2557 /* Scramble the insn chain. */
2558 reorder_insns (start, end, a->end);
2560 /* Now blocks A and B are contiguous. Merge them. */
2561 merge_blocks_nomove (a, b);
2565 fprintf (rtl_dump_file, "Moved block %d after %d and merged.\n",
2566 b->index, a->index);
2572 /* Attempt to merge basic blocks that are potentially non-adjacent.
2573 Return true iff the attempt succeeded. */
2576 merge_blocks (e, b, c)
2580 /* If C has a tail recursion label, do not merge. There is no
2581 edge recorded from the call_placeholder back to this label, as
2582 that would make optimize_sibling_and_tail_recursive_calls more
2583 complex for no gain. */
2584 if (GET_CODE (c->head) == CODE_LABEL
2585 && tail_recursion_label_p (c->head))
2588 /* If B has a fallthru edge to C, no need to move anything. */
2589 if (e->flags & EDGE_FALLTHRU)
2591 merge_blocks_nomove (b, c);
2595 fprintf (rtl_dump_file, "Merged %d and %d without moving.\n",
2596 b->index, c->index);
2604 int c_has_outgoing_fallthru;
2605 int b_has_incoming_fallthru;
2607 /* We must make sure to not munge nesting of exception regions,
2608 lexical blocks, and loop notes.
2610 The first is taken care of by requiring that the active eh
2611 region at the end of one block always matches the active eh
2612 region at the beginning of the next block.
2614 The later two are taken care of by squeezing out all the notes. */
2616 /* ??? A throw/catch edge (or any abnormal edge) should be rarely
2617 executed and we may want to treat blocks which have two out
2618 edges, one normal, one abnormal as only having one edge for
2619 block merging purposes. */
2621 for (tmp_edge = c->succ; tmp_edge; tmp_edge = tmp_edge->succ_next)
2622 if (tmp_edge->flags & EDGE_FALLTHRU)
2624 c_has_outgoing_fallthru = (tmp_edge != NULL);
2626 for (tmp_edge = b->pred; tmp_edge; tmp_edge = tmp_edge->pred_next)
2627 if (tmp_edge->flags & EDGE_FALLTHRU)
2629 b_has_incoming_fallthru = (tmp_edge != NULL);
2631 /* If B does not have an incoming fallthru, then it can be moved
2632 immediately before C without introducing or modifying jumps.
2633 C cannot be the first block, so we do not have to worry about
2634 accessing a non-existent block. */
2635 if (! b_has_incoming_fallthru)
2636 return merge_blocks_move_predecessor_nojumps (b, c);
2638 /* Otherwise, we're going to try to move C after B. If C does
2639 not have an outgoing fallthru, then it can be moved
2640 immediately after B without introducing or modifying jumps. */
2641 if (! c_has_outgoing_fallthru)
2642 return merge_blocks_move_successor_nojumps (b, c);
2644 /* Otherwise, we'll need to insert an extra jump, and possibly
2645 a new block to contain it. */
2646 /* ??? Not implemented yet. */
2652 /* Top level driver for merge_blocks. */
2659 /* Attempt to merge blocks as made possible by edge removal. If a block
2660 has only one successor, and the successor has only one predecessor,
2661 they may be combined. */
2663 for (i = 0; i < n_basic_blocks;)
2665 basic_block c, b = BASIC_BLOCK (i);
2668 /* A loop because chains of blocks might be combineable. */
2669 while ((s = b->succ) != NULL
2670 && s->succ_next == NULL
2671 && (s->flags & EDGE_EH) == 0
2672 && (c = s->dest) != EXIT_BLOCK_PTR
2673 && c->pred->pred_next == NULL
2674 /* If the jump insn has side effects, we can't kill the edge. */
2675 && (GET_CODE (b->end) != JUMP_INSN
2676 || onlyjump_p (b->end))
2677 && merge_blocks (s, b, c))
2680 /* Don't get confused by the index shift caused by deleting blocks. */
2685 /* The given edge should potentially be a fallthru edge. If that is in
2686 fact true, delete the jump and barriers that are in the way. */
2689 tidy_fallthru_edge (e, b, c)
2695 /* ??? In a late-running flow pass, other folks may have deleted basic
2696 blocks by nopping out blocks, leaving multiple BARRIERs between here
2697 and the target label. They ought to be chastized and fixed.
2699 We can also wind up with a sequence of undeletable labels between
2700 one block and the next.
2702 So search through a sequence of barriers, labels, and notes for
2703 the head of block C and assert that we really do fall through. */
2705 if (next_real_insn (b->end) != next_real_insn (PREV_INSN (c->head)))
2708 /* Remove what will soon cease being the jump insn from the source block.
2709 If block B consisted only of this single jump, turn it into a deleted
2712 if (GET_CODE (q) == JUMP_INSN
2714 && (any_uncondjump_p (q)
2715 || (b->succ == e && e->succ_next == NULL)))
2718 /* If this was a conditional jump, we need to also delete
2719 the insn that set cc0. */
2720 if (any_condjump_p (q) && sets_cc0_p (PREV_INSN (q)))
2727 NOTE_LINE_NUMBER (q) = NOTE_INSN_DELETED;
2728 NOTE_SOURCE_FILE (q) = 0;
2734 /* We don't want a block to end on a line-number note since that has
2735 the potential of changing the code between -g and not -g. */
2736 while (GET_CODE (q) == NOTE && NOTE_LINE_NUMBER (q) >= 0)
2743 /* Selectively unlink the sequence. */
2744 if (q != PREV_INSN (c->head))
2745 flow_delete_insn_chain (NEXT_INSN (q), PREV_INSN (c->head));
2747 e->flags |= EDGE_FALLTHRU;
2750 /* Fix up edges that now fall through, or rather should now fall through
2751 but previously required a jump around now deleted blocks. Simplify
2752 the search by only examining blocks numerically adjacent, since this
2753 is how find_basic_blocks created them. */
2756 tidy_fallthru_edges ()
2760 for (i = 1; i < n_basic_blocks; ++i)
2762 basic_block b = BASIC_BLOCK (i - 1);
2763 basic_block c = BASIC_BLOCK (i);
2766 /* We care about simple conditional or unconditional jumps with
2769 If we had a conditional branch to the next instruction when
2770 find_basic_blocks was called, then there will only be one
2771 out edge for the block which ended with the conditional
2772 branch (since we do not create duplicate edges).
2774 Furthermore, the edge will be marked as a fallthru because we
2775 merge the flags for the duplicate edges. So we do not want to
2776 check that the edge is not a FALLTHRU edge. */
2777 if ((s = b->succ) != NULL
2778 && ! (s->flags & EDGE_COMPLEX)
2779 && s->succ_next == NULL
2781 /* If the jump insn has side effects, we can't tidy the edge. */
2782 && (GET_CODE (b->end) != JUMP_INSN
2783 || onlyjump_p (b->end)))
2784 tidy_fallthru_edge (s, b, c);
2788 /* Perform data flow analysis.
2789 F is the first insn of the function; FLAGS is a set of PROP_* flags
2790 to be used in accumulating flow info. */
2793 life_analysis (f, file, flags)
2798 #ifdef ELIMINABLE_REGS
2800 static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
2803 /* Record which registers will be eliminated. We use this in
2806 CLEAR_HARD_REG_SET (elim_reg_set);
2808 #ifdef ELIMINABLE_REGS
2809 for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
2810 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
2812 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
2816 flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC);
2818 /* The post-reload life analysis have (on a global basis) the same
2819 registers live as was computed by reload itself. elimination
2820 Otherwise offsets and such may be incorrect.
2822 Reload will make some registers as live even though they do not
2825 We don't want to create new auto-incs after reload, since they
2826 are unlikely to be useful and can cause problems with shared
2828 if (reload_completed)
2829 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
2831 /* We want alias analysis information for local dead store elimination. */
2832 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
2833 init_alias_analysis ();
2835 /* Always remove no-op moves. Do this before other processing so
2836 that we don't have to keep re-scanning them. */
2837 delete_noop_moves (f);
2839 /* Some targets can emit simpler epilogues if they know that sp was
2840 not ever modified during the function. After reload, of course,
2841 we've already emitted the epilogue so there's no sense searching. */
2842 if (! reload_completed)
2843 notice_stack_pointer_modification (f);
2845 /* Allocate and zero out data structures that will record the
2846 data from lifetime analysis. */
2847 allocate_reg_life_data ();
2848 allocate_bb_life_data ();
2850 /* Find the set of registers live on function exit. */
2851 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
2853 /* "Update" life info from zero. It'd be nice to begin the
2854 relaxation with just the exit and noreturn blocks, but that set
2855 is not immediately handy. */
2857 if (flags & PROP_REG_INFO)
2858 memset (regs_ever_live, 0, sizeof (regs_ever_live));
2859 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
2862 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
2863 end_alias_analysis ();
2866 dump_flow_info (file);
2868 free_basic_block_vars (1);
2870 #ifdef ENABLE_CHECKING
2874 /* Search for any REG_LABEL notes which reference deleted labels. */
2875 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
2877 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
2879 if (inote && GET_CODE (inote) == NOTE_INSN_DELETED_LABEL)
2886 /* A subroutine of verify_wide_reg, called through for_each_rtx.
2887 Search for REGNO. If found, abort if it is not wider than word_mode. */
2890 verify_wide_reg_1 (px, pregno)
2895 unsigned int regno = *(int *) pregno;
2897 if (GET_CODE (x) == REG && REGNO (x) == regno)
2899 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
2906 /* A subroutine of verify_local_live_at_start. Search through insns
2907 between HEAD and END looking for register REGNO. */
2910 verify_wide_reg (regno, head, end)
2917 && for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no))
2921 head = NEXT_INSN (head);
2924 /* We didn't find the register at all. Something's way screwy. */
2926 fprintf (rtl_dump_file, "Aborting in verify_wide_reg; reg %d\n", regno);
2927 print_rtl_and_abort ();
2930 /* A subroutine of update_life_info. Verify that there are no untoward
2931 changes in live_at_start during a local update. */
2934 verify_local_live_at_start (new_live_at_start, bb)
2935 regset new_live_at_start;
2938 if (reload_completed)
2940 /* After reload, there are no pseudos, nor subregs of multi-word
2941 registers. The regsets should exactly match. */
2942 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
2946 fprintf (rtl_dump_file,
2947 "live_at_start mismatch in bb %d, aborting\n",
2949 debug_bitmap_file (rtl_dump_file, bb->global_live_at_start);
2950 debug_bitmap_file (rtl_dump_file, new_live_at_start);
2952 print_rtl_and_abort ();
2959 /* Find the set of changed registers. */
2960 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
2962 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
2964 /* No registers should die. */
2965 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
2968 fprintf (rtl_dump_file,
2969 "Register %d died unexpectedly in block %d\n", i,
2971 print_rtl_and_abort ();
2974 /* Verify that the now-live register is wider than word_mode. */
2975 verify_wide_reg (i, bb->head, bb->end);
2980 /* Updates life information starting with the basic blocks set in BLOCKS.
2981 If BLOCKS is null, consider it to be the universal set.
2983 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
2984 we are only expecting local modifications to basic blocks. If we find
2985 extra registers live at the beginning of a block, then we either killed
2986 useful data, or we have a broken split that wants data not provided.
2987 If we find registers removed from live_at_start, that means we have
2988 a broken peephole that is killing a register it shouldn't.
2990 ??? This is not true in one situation -- when a pre-reload splitter
2991 generates subregs of a multi-word pseudo, current life analysis will
2992 lose the kill. So we _can_ have a pseudo go live. How irritating.
2994 Including PROP_REG_INFO does not properly refresh regs_ever_live
2995 unless the caller resets it to zero. */
2998 update_life_info (blocks, extent, prop_flags)
3000 enum update_life_extent extent;
3004 regset_head tmp_head;
3007 tmp = INITIALIZE_REG_SET (tmp_head);
3009 /* For a global update, we go through the relaxation process again. */
3010 if (extent != UPDATE_LIFE_LOCAL)
3012 calculate_global_regs_live (blocks, blocks,
3013 prop_flags & PROP_SCAN_DEAD_CODE);
3015 /* If asked, remove notes from the blocks we'll update. */
3016 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
3017 count_or_remove_death_notes (blocks, 1);
3022 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
3024 basic_block bb = BASIC_BLOCK (i);
3026 COPY_REG_SET (tmp, bb->global_live_at_end);
3027 propagate_block (bb, tmp, NULL, NULL, prop_flags);
3029 if (extent == UPDATE_LIFE_LOCAL)
3030 verify_local_live_at_start (tmp, bb);
3035 for (i = n_basic_blocks - 1; i >= 0; --i)
3037 basic_block bb = BASIC_BLOCK (i);
3039 COPY_REG_SET (tmp, bb->global_live_at_end);
3040 propagate_block (bb, tmp, NULL, NULL, prop_flags);
3042 if (extent == UPDATE_LIFE_LOCAL)
3043 verify_local_live_at_start (tmp, bb);
3049 if (prop_flags & PROP_REG_INFO)
3051 /* The only pseudos that are live at the beginning of the function
3052 are those that were not set anywhere in the function. local-alloc
3053 doesn't know how to handle these correctly, so mark them as not
3054 local to any one basic block. */
3055 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
3056 FIRST_PSEUDO_REGISTER, i,
3057 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
3059 /* We have a problem with any pseudoreg that lives across the setjmp.
3060 ANSI says that if a user variable does not change in value between
3061 the setjmp and the longjmp, then the longjmp preserves it. This
3062 includes longjmp from a place where the pseudo appears dead.
3063 (In principle, the value still exists if it is in scope.)
3064 If the pseudo goes in a hard reg, some other value may occupy
3065 that hard reg where this pseudo is dead, thus clobbering the pseudo.
3066 Conclusion: such a pseudo must not go in a hard reg. */
3067 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
3068 FIRST_PSEUDO_REGISTER, i,
3070 if (regno_reg_rtx[i] != 0)
3072 REG_LIVE_LENGTH (i) = -1;
3073 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
3079 /* Free the variables allocated by find_basic_blocks.
3081 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
3084 free_basic_block_vars (keep_head_end_p)
3085 int keep_head_end_p;
3087 if (basic_block_for_insn)
3089 VARRAY_FREE (basic_block_for_insn);
3090 basic_block_for_insn = NULL;
3093 if (! keep_head_end_p)
3095 if (basic_block_info)
3098 VARRAY_FREE (basic_block_info);
3102 ENTRY_BLOCK_PTR->aux = NULL;
3103 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
3104 EXIT_BLOCK_PTR->aux = NULL;
3105 EXIT_BLOCK_PTR->global_live_at_start = NULL;
3109 /* Return nonzero if an insn consists only of SETs, each of which only sets a
3116 rtx pat = PATTERN (insn);
3118 /* Insns carrying these notes are useful later on. */
3119 if (find_reg_note (insn, REG_EQUAL, NULL_RTX))
3122 if (GET_CODE (pat) == SET && set_noop_p (pat))
3125 if (GET_CODE (pat) == PARALLEL)
3128 /* If nothing but SETs of registers to themselves,
3129 this insn can also be deleted. */
3130 for (i = 0; i < XVECLEN (pat, 0); i++)
3132 rtx tem = XVECEXP (pat, 0, i);
3134 if (GET_CODE (tem) == USE
3135 || GET_CODE (tem) == CLOBBER)
3138 if (GET_CODE (tem) != SET || ! set_noop_p (tem))
3147 /* Delete any insns that copy a register to itself. */
3150 delete_noop_moves (f)
3154 for (insn = f; insn; insn = NEXT_INSN (insn))
3156 if (GET_CODE (insn) == INSN && noop_move_p (insn))
3158 PUT_CODE (insn, NOTE);
3159 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
3160 NOTE_SOURCE_FILE (insn) = 0;
3165 /* Determine if the stack pointer is constant over the life of the function.
3166 Only useful before prologues have been emitted. */
3169 notice_stack_pointer_modification_1 (x, pat, data)
3171 rtx pat ATTRIBUTE_UNUSED;
3172 void *data ATTRIBUTE_UNUSED;
3174 if (x == stack_pointer_rtx
3175 /* The stack pointer is only modified indirectly as the result
3176 of a push until later in flow. See the comments in rtl.texi
3177 regarding Embedded Side-Effects on Addresses. */
3178 || (GET_CODE (x) == MEM
3179 && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
3180 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
3181 current_function_sp_is_unchanging = 0;
3185 notice_stack_pointer_modification (f)
3190 /* Assume that the stack pointer is unchanging if alloca hasn't
3192 current_function_sp_is_unchanging = !current_function_calls_alloca;
3193 if (! current_function_sp_is_unchanging)
3196 for (insn = f; insn; insn = NEXT_INSN (insn))
3200 /* Check if insn modifies the stack pointer. */
3201 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
3203 if (! current_function_sp_is_unchanging)
3209 /* Mark a register in SET. Hard registers in large modes get all
3210 of their component registers set as well. */
3213 mark_reg (reg, xset)
3217 regset set = (regset) xset;
3218 int regno = REGNO (reg);
3220 if (GET_MODE (reg) == BLKmode)
3223 SET_REGNO_REG_SET (set, regno);
3224 if (regno < FIRST_PSEUDO_REGISTER)
3226 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
3228 SET_REGNO_REG_SET (set, regno + n);
3232 /* Mark those regs which are needed at the end of the function as live
3233 at the end of the last basic block. */
3236 mark_regs_live_at_end (set)
3241 /* If exiting needs the right stack value, consider the stack pointer
3242 live at the end of the function. */
3243 if ((HAVE_epilogue && reload_completed)
3244 || ! EXIT_IGNORE_STACK
3245 || (! FRAME_POINTER_REQUIRED
3246 && ! current_function_calls_alloca
3247 && flag_omit_frame_pointer)
3248 || current_function_sp_is_unchanging)
3250 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
3253 /* Mark the frame pointer if needed at the end of the function. If
3254 we end up eliminating it, it will be removed from the live list
3255 of each basic block by reload. */
3257 if (! reload_completed || frame_pointer_needed)
3259 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
3260 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3261 /* If they are different, also mark the hard frame pointer as live. */
3262 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
3263 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
3267 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
3268 /* Many architectures have a GP register even without flag_pic.
3269 Assume the pic register is not in use, or will be handled by
3270 other means, if it is not fixed. */
3271 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
3272 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
3273 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
3276 /* Mark all global registers, and all registers used by the epilogue
3277 as being live at the end of the function since they may be
3278 referenced by our caller. */
3279 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3280 if (global_regs[i] || EPILOGUE_USES (i))
3281 SET_REGNO_REG_SET (set, i);
3283 if (HAVE_epilogue && reload_completed)
3285 /* Mark all call-saved registers that we actually used. */
3286 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3287 if (regs_ever_live[i] && ! call_used_regs[i] && ! LOCAL_REGNO (i))
3288 SET_REGNO_REG_SET (set, i);
3291 #ifdef EH_RETURN_DATA_REGNO
3292 /* Mark the registers that will contain data for the handler. */
3293 if (reload_completed && current_function_calls_eh_return)
3296 unsigned regno = EH_RETURN_DATA_REGNO(i);
3297 if (regno == INVALID_REGNUM)
3299 SET_REGNO_REG_SET (set, regno);
3302 #ifdef EH_RETURN_STACKADJ_RTX
3303 if ((! HAVE_epilogue || ! reload_completed)
3304 && current_function_calls_eh_return)
3306 rtx tmp = EH_RETURN_STACKADJ_RTX;
3307 if (tmp && REG_P (tmp))
3308 mark_reg (tmp, set);
3311 #ifdef EH_RETURN_HANDLER_RTX
3312 if ((! HAVE_epilogue || ! reload_completed)
3313 && current_function_calls_eh_return)
3315 rtx tmp = EH_RETURN_HANDLER_RTX;
3316 if (tmp && REG_P (tmp))
3317 mark_reg (tmp, set);
3321 /* Mark function return value. */
3322 diddle_return_value (mark_reg, set);
3325 /* Callback function for for_each_successor_phi. DATA is a regset.
3326 Sets the SRC_REGNO, the regno of the phi alternative for phi node
3327 INSN, in the regset. */
3330 set_phi_alternative_reg (insn, dest_regno, src_regno, data)
3331 rtx insn ATTRIBUTE_UNUSED;
3332 int dest_regno ATTRIBUTE_UNUSED;
3336 regset live = (regset) data;
3337 SET_REGNO_REG_SET (live, src_regno);
3341 /* Propagate global life info around the graph of basic blocks. Begin
3342 considering blocks with their corresponding bit set in BLOCKS_IN.
3343 If BLOCKS_IN is null, consider it the universal set.
3345 BLOCKS_OUT is set for every block that was changed. */
3348 calculate_global_regs_live (blocks_in, blocks_out, flags)
3349 sbitmap blocks_in, blocks_out;
3352 basic_block *queue, *qhead, *qtail, *qend;
3353 regset tmp, new_live_at_end, call_used;
3354 regset_head tmp_head, call_used_head;
3355 regset_head new_live_at_end_head;
3358 tmp = INITIALIZE_REG_SET (tmp_head);
3359 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
3360 call_used = INITIALIZE_REG_SET (call_used_head);
3362 /* Inconveniently, this is only redily available in hard reg set form. */
3363 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
3364 if (call_used_regs[i])
3365 SET_REGNO_REG_SET (call_used, i);
3367 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
3368 because the `head == tail' style test for an empty queue doesn't
3369 work with a full queue. */
3370 queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
3372 qhead = qend = queue + n_basic_blocks + 2;
3374 /* Queue the blocks set in the initial mask. Do this in reverse block
3375 number order so that we are more likely for the first round to do
3376 useful work. We use AUX non-null to flag that the block is queued. */
3379 /* Clear out the garbage that might be hanging out in bb->aux. */
3380 for (i = n_basic_blocks - 1; i >= 0; --i)
3381 BASIC_BLOCK (i)->aux = NULL;
3383 EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
3385 basic_block bb = BASIC_BLOCK (i);
3392 for (i = 0; i < n_basic_blocks; ++i)
3394 basic_block bb = BASIC_BLOCK (i);
3401 sbitmap_zero (blocks_out);
3403 /* We work through the queue until there are no more blocks. What
3404 is live at the end of this block is precisely the union of what
3405 is live at the beginning of all its successors. So, we set its
3406 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
3407 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
3408 this block by walking through the instructions in this block in
3409 reverse order and updating as we go. If that changed
3410 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
3411 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
3413 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
3414 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
3415 must either be live at the end of the block, or used within the
3416 block. In the latter case, it will certainly never disappear
3417 from GLOBAL_LIVE_AT_START. In the former case, the register
3418 could go away only if it disappeared from GLOBAL_LIVE_AT_START
3419 for one of the successor blocks. By induction, that cannot
3421 while (qhead != qtail)
3423 int rescan, changed;
3432 /* Begin by propagating live_at_start from the successor blocks. */
3433 CLEAR_REG_SET (new_live_at_end);
3434 for (e = bb->succ; e; e = e->succ_next)
3436 basic_block sb = e->dest;
3438 /* Call-clobbered registers die across exception and call edges. */
3439 /* ??? Abnormal call edges ignored for the moment, as this gets
3440 confused by sibling call edges, which crashes reg-stack. */
3441 if (e->flags & EDGE_EH)
3443 bitmap_operation (tmp, sb->global_live_at_start,
3444 call_used, BITMAP_AND_COMPL);
3445 IOR_REG_SET (new_live_at_end, tmp);
3448 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
3451 /* The all-important stack pointer must always be live. */
3452 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
3454 /* Before reload, there are a few registers that must be forced
3455 live everywhere -- which might not already be the case for
3456 blocks within infinite loops. */
3457 if (! reload_completed)
3459 /* Any reference to any pseudo before reload is a potential
3460 reference of the frame pointer. */
3461 SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
3463 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3464 /* Pseudos with argument area equivalences may require
3465 reloading via the argument pointer. */
3466 if (fixed_regs[ARG_POINTER_REGNUM])
3467 SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
3470 /* Any constant, or pseudo with constant equivalences, may
3471 require reloading from memory using the pic register. */
3472 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
3473 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
3474 SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
3477 /* Regs used in phi nodes are not included in
3478 global_live_at_start, since they are live only along a
3479 particular edge. Set those regs that are live because of a
3480 phi node alternative corresponding to this particular block. */
3482 for_each_successor_phi (bb, &set_phi_alternative_reg,
3485 if (bb == ENTRY_BLOCK_PTR)
3487 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3491 /* On our first pass through this block, we'll go ahead and continue.
3492 Recognize first pass by local_set NULL. On subsequent passes, we
3493 get to skip out early if live_at_end wouldn't have changed. */
3495 if (bb->local_set == NULL)
3497 bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3498 bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3503 /* If any bits were removed from live_at_end, we'll have to
3504 rescan the block. This wouldn't be necessary if we had
3505 precalculated local_live, however with PROP_SCAN_DEAD_CODE
3506 local_live is really dependent on live_at_end. */
3507 CLEAR_REG_SET (tmp);
3508 rescan = bitmap_operation (tmp, bb->global_live_at_end,
3509 new_live_at_end, BITMAP_AND_COMPL);
3513 /* If any of the registers in the new live_at_end set are
3514 conditionally set in this basic block, we must rescan.
3515 This is because conditional lifetimes at the end of the
3516 block do not just take the live_at_end set into account,
3517 but also the liveness at the start of each successor
3518 block. We can miss changes in those sets if we only
3519 compare the new live_at_end against the previous one. */
3520 CLEAR_REG_SET (tmp);
3521 rescan = bitmap_operation (tmp, new_live_at_end,
3522 bb->cond_local_set, BITMAP_AND);
3527 /* Find the set of changed bits. Take this opportunity
3528 to notice that this set is empty and early out. */
3529 CLEAR_REG_SET (tmp);
3530 changed = bitmap_operation (tmp, bb->global_live_at_end,
3531 new_live_at_end, BITMAP_XOR);
3535 /* If any of the changed bits overlap with local_set,
3536 we'll have to rescan the block. Detect overlap by
3537 the AND with ~local_set turning off bits. */
3538 rescan = bitmap_operation (tmp, tmp, bb->local_set,
3543 /* Let our caller know that BB changed enough to require its
3544 death notes updated. */
3546 SET_BIT (blocks_out, bb->index);
3550 /* Add to live_at_start the set of all registers in
3551 new_live_at_end that aren't in the old live_at_end. */
3553 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
3555 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3557 changed = bitmap_operation (bb->global_live_at_start,
3558 bb->global_live_at_start,
3565 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3567 /* Rescan the block insn by insn to turn (a copy of) live_at_end
3568 into live_at_start. */
3569 propagate_block (bb, new_live_at_end, bb->local_set,
3570 bb->cond_local_set, flags);
3572 /* If live_at start didn't change, no need to go farther. */
3573 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
3576 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
3579 /* Queue all predecessors of BB so that we may re-examine
3580 their live_at_end. */
3581 for (e = bb->pred; e; e = e->pred_next)
3583 basic_block pb = e->src;
3584 if (pb->aux == NULL)
3595 FREE_REG_SET (new_live_at_end);
3596 FREE_REG_SET (call_used);
3600 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
3602 basic_block bb = BASIC_BLOCK (i);
3603 FREE_REG_SET (bb->local_set);
3604 FREE_REG_SET (bb->cond_local_set);
3609 for (i = n_basic_blocks - 1; i >= 0; --i)
3611 basic_block bb = BASIC_BLOCK (i);
3612 FREE_REG_SET (bb->local_set);
3613 FREE_REG_SET (bb->cond_local_set);
3620 /* Subroutines of life analysis. */
3622 /* Allocate the permanent data structures that represent the results
3623 of life analysis. Not static since used also for stupid life analysis. */
3626 allocate_bb_life_data ()
3630 for (i = 0; i < n_basic_blocks; i++)
3632 basic_block bb = BASIC_BLOCK (i);
3634 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3635 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3638 ENTRY_BLOCK_PTR->global_live_at_end
3639 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3640 EXIT_BLOCK_PTR->global_live_at_start
3641 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3643 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3647 allocate_reg_life_data ()
3651 max_regno = max_reg_num ();
3653 /* Recalculate the register space, in case it has grown. Old style
3654 vector oriented regsets would set regset_{size,bytes} here also. */
3655 allocate_reg_info (max_regno, FALSE, FALSE);
3657 /* Reset all the data we'll collect in propagate_block and its
3659 for (i = 0; i < max_regno; i++)
3663 REG_N_DEATHS (i) = 0;
3664 REG_N_CALLS_CROSSED (i) = 0;
3665 REG_LIVE_LENGTH (i) = 0;
3666 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
3670 /* Delete dead instructions for propagate_block. */
3673 propagate_block_delete_insn (bb, insn)
3677 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
3679 /* If the insn referred to a label, and that label was attached to
3680 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
3681 pretty much mandatory to delete it, because the ADDR_VEC may be
3682 referencing labels that no longer exist.
3684 INSN may reference a deleted label, particularly when a jump
3685 table has been optimized into a direct jump. There's no
3686 real good way to fix up the reference to the deleted label
3687 when the label is deleted, so we just allow it here.
3689 After dead code elimination is complete, we do search for
3690 any REG_LABEL notes which reference deleted labels as a
3693 if (inote && GET_CODE (inote) == CODE_LABEL)
3695 rtx label = XEXP (inote, 0);
3698 /* The label may be forced if it has been put in the constant
3699 pool. If that is the only use we must discard the table
3700 jump following it, but not the label itself. */
3701 if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
3702 && (next = next_nonnote_insn (label)) != NULL
3703 && GET_CODE (next) == JUMP_INSN
3704 && (GET_CODE (PATTERN (next)) == ADDR_VEC
3705 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
3707 rtx pat = PATTERN (next);
3708 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
3709 int len = XVECLEN (pat, diff_vec_p);
3712 for (i = 0; i < len; i++)
3713 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
3715 flow_delete_insn (next);
3719 if (bb->end == insn)
3720 bb->end = PREV_INSN (insn);
3721 flow_delete_insn (insn);
3724 /* Delete dead libcalls for propagate_block. Return the insn
3725 before the libcall. */
3728 propagate_block_delete_libcall (bb, insn, note)
3732 rtx first = XEXP (note, 0);
3733 rtx before = PREV_INSN (first);
3735 if (insn == bb->end)
3738 flow_delete_insn_chain (first, insn);
3742 /* Update the life-status of regs for one insn. Return the previous insn. */
3745 propagate_one_insn (pbi, insn)
3746 struct propagate_block_info *pbi;
3749 rtx prev = PREV_INSN (insn);
3750 int flags = pbi->flags;
3751 int insn_is_dead = 0;
3752 int libcall_is_dead = 0;
3756 if (! INSN_P (insn))
3759 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
3760 if (flags & PROP_SCAN_DEAD_CODE)
3762 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
3763 libcall_is_dead = (insn_is_dead && note != 0
3764 && libcall_dead_p (pbi, note, insn));
3767 /* If an instruction consists of just dead store(s) on final pass,
3769 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
3771 /* If we're trying to delete a prologue or epilogue instruction
3772 that isn't flagged as possibly being dead, something is wrong.
3773 But if we are keeping the stack pointer depressed, we might well
3774 be deleting insns that are used to compute the amount to update
3775 it by, so they are fine. */
3776 if (reload_completed
3777 && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
3778 && (TYPE_RETURNS_STACK_DEPRESSED
3779 (TREE_TYPE (current_function_decl))))
3780 && (((HAVE_epilogue || HAVE_prologue)
3781 && prologue_epilogue_contains (insn))
3782 || (HAVE_sibcall_epilogue
3783 && sibcall_epilogue_contains (insn)))
3784 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
3787 /* Record sets. Do this even for dead instructions, since they
3788 would have killed the values if they hadn't been deleted. */
3789 mark_set_regs (pbi, PATTERN (insn), insn);
3791 /* CC0 is now known to be dead. Either this insn used it,
3792 in which case it doesn't anymore, or clobbered it,
3793 so the next insn can't use it. */
3796 if (libcall_is_dead)
3797 prev = propagate_block_delete_libcall (pbi->bb, insn, note);
3799 propagate_block_delete_insn (pbi->bb, insn);
3804 /* See if this is an increment or decrement that can be merged into
3805 a following memory address. */
3808 register rtx x = single_set (insn);
3810 /* Does this instruction increment or decrement a register? */
3811 if ((flags & PROP_AUTOINC)
3813 && GET_CODE (SET_DEST (x)) == REG
3814 && (GET_CODE (SET_SRC (x)) == PLUS
3815 || GET_CODE (SET_SRC (x)) == MINUS)
3816 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
3817 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
3818 /* Ok, look for a following memory ref we can combine with.
3819 If one is found, change the memory ref to a PRE_INC
3820 or PRE_DEC, cancel this insn, and return 1.
3821 Return 0 if nothing has been done. */
3822 && try_pre_increment_1 (pbi, insn))
3825 #endif /* AUTO_INC_DEC */
3827 CLEAR_REG_SET (pbi->new_set);
3829 /* If this is not the final pass, and this insn is copying the value of
3830 a library call and it's dead, don't scan the insns that perform the
3831 library call, so that the call's arguments are not marked live. */
3832 if (libcall_is_dead)
3834 /* Record the death of the dest reg. */
3835 mark_set_regs (pbi, PATTERN (insn), insn);
3837 insn = XEXP (note, 0);
3838 return PREV_INSN (insn);
3840 else if (GET_CODE (PATTERN (insn)) == SET
3841 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
3842 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
3843 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
3844 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
3845 /* We have an insn to pop a constant amount off the stack.
3846 (Such insns use PLUS regardless of the direction of the stack,
3847 and any insn to adjust the stack by a constant is always a pop.)
3848 These insns, if not dead stores, have no effect on life. */
3852 /* Any regs live at the time of a call instruction must not go
3853 in a register clobbered by calls. Find all regs now live and
3854 record this for them. */
3856 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
3857 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
3858 { REG_N_CALLS_CROSSED (i)++; });
3860 /* Record sets. Do this even for dead instructions, since they
3861 would have killed the values if they hadn't been deleted. */
3862 mark_set_regs (pbi, PATTERN (insn), insn);
3864 if (GET_CODE (insn) == CALL_INSN)
3870 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
3871 cond = COND_EXEC_TEST (PATTERN (insn));
3873 /* Non-constant calls clobber memory. */
3874 if (! CONST_CALL_P (insn))
3876 free_EXPR_LIST_list (&pbi->mem_set_list);
3877 pbi->mem_set_list_len = 0;
3880 /* There may be extra registers to be clobbered. */
3881 for (note = CALL_INSN_FUNCTION_USAGE (insn);
3883 note = XEXP (note, 1))
3884 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
3885 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
3886 cond, insn, pbi->flags);
3888 /* Calls change all call-used and global registers. */
3889 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3890 if (call_used_regs[i] && ! global_regs[i]
3893 /* We do not want REG_UNUSED notes for these registers. */
3894 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
3896 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
3900 /* If an insn doesn't use CC0, it becomes dead since we assume
3901 that every insn clobbers it. So show it dead here;
3902 mark_used_regs will set it live if it is referenced. */
3907 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
3909 /* Sometimes we may have inserted something before INSN (such as a move)
3910 when we make an auto-inc. So ensure we will scan those insns. */
3912 prev = PREV_INSN (insn);
3915 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
3921 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
3922 cond = COND_EXEC_TEST (PATTERN (insn));
3924 /* Calls use their arguments. */
3925 for (note = CALL_INSN_FUNCTION_USAGE (insn);
3927 note = XEXP (note, 1))
3928 if (GET_CODE (XEXP (note, 0)) == USE)
3929 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
3932 /* The stack ptr is used (honorarily) by a CALL insn. */
3933 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
3935 /* Calls may also reference any of the global registers,
3936 so they are made live. */
3937 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3939 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
3944 /* On final pass, update counts of how many insns in which each reg
3946 if (flags & PROP_REG_INFO)
3947 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
3948 { REG_LIVE_LENGTH (i)++; });
3953 /* Initialize a propagate_block_info struct for public consumption.
3954 Note that the structure itself is opaque to this file, but that
3955 the user can use the regsets provided here. */
3957 struct propagate_block_info *
3958 init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
3960 regset live, local_set, cond_local_set;
3963 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
3966 pbi->reg_live = live;
3967 pbi->mem_set_list = NULL_RTX;
3968 pbi->mem_set_list_len = 0;
3969 pbi->local_set = local_set;
3970 pbi->cond_local_set = cond_local_set;
3974 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
3975 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
3977 pbi->reg_next_use = NULL;
3979 pbi->new_set = BITMAP_XMALLOC ();
3981 #ifdef HAVE_conditional_execution
3982 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
3983 free_reg_cond_life_info);
3984 pbi->reg_cond_reg = BITMAP_XMALLOC ();
3986 /* If this block ends in a conditional branch, for each register live
3987 from one side of the branch and not the other, record the register
3988 as conditionally dead. */
3989 if (GET_CODE (bb->end) == JUMP_INSN
3990 && any_condjump_p (bb->end))
3992 regset_head diff_head;
3993 regset diff = INITIALIZE_REG_SET (diff_head);
3994 basic_block bb_true, bb_false;
3995 rtx cond_true, cond_false, set_src;
3998 /* Identify the successor blocks. */
3999 bb_true = bb->succ->dest;
4000 if (bb->succ->succ_next != NULL)
4002 bb_false = bb->succ->succ_next->dest;
4004 if (bb->succ->flags & EDGE_FALLTHRU)
4006 basic_block t = bb_false;
4010 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
4015 /* This can happen with a conditional jump to the next insn. */
4016 if (JUMP_LABEL (bb->end) != bb_true->head)
4019 /* Simplest way to do nothing. */
4023 /* Extract the condition from the branch. */
4024 set_src = SET_SRC (pc_set (bb->end));
4025 cond_true = XEXP (set_src, 0);
4026 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
4027 GET_MODE (cond_true), XEXP (cond_true, 0),
4028 XEXP (cond_true, 1));
4029 if (GET_CODE (XEXP (set_src, 1)) == PC)
4032 cond_false = cond_true;
4036 /* Compute which register lead different lives in the successors. */
4037 if (bitmap_operation (diff, bb_true->global_live_at_start,
4038 bb_false->global_live_at_start, BITMAP_XOR))
4040 rtx reg = XEXP (cond_true, 0);
4042 if (GET_CODE (reg) == SUBREG)
4043 reg = SUBREG_REG (reg);
4045 if (GET_CODE (reg) != REG)
4048 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
4050 /* For each such register, mark it conditionally dead. */
4051 EXECUTE_IF_SET_IN_REG_SET
4054 struct reg_cond_life_info *rcli;
4057 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
4059 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
4063 rcli->condition = cond;
4064 rcli->stores = const0_rtx;
4065 rcli->orig_condition = cond;
4067 splay_tree_insert (pbi->reg_cond_dead, i,
4068 (splay_tree_value) rcli);
4072 FREE_REG_SET (diff);
4076 /* If this block has no successors, any stores to the frame that aren't
4077 used later in the block are dead. So make a pass over the block
4078 recording any such that are made and show them dead at the end. We do
4079 a very conservative and simple job here. */
4081 && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
4082 && (TYPE_RETURNS_STACK_DEPRESSED
4083 (TREE_TYPE (current_function_decl))))
4084 && (flags & PROP_SCAN_DEAD_CODE)
4085 && (bb->succ == NULL
4086 || (bb->succ->succ_next == NULL
4087 && bb->succ->dest == EXIT_BLOCK_PTR
4088 && ! current_function_calls_eh_return)))
4091 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
4092 if (GET_CODE (insn) == INSN
4093 && (set = single_set (insn))
4094 && GET_CODE (SET_DEST (set)) == MEM)
4096 rtx mem = SET_DEST (set);
4097 rtx canon_mem = canon_rtx (mem);
4099 /* This optimization is performed by faking a store to the
4100 memory at the end of the block. This doesn't work for
4101 unchanging memories because multiple stores to unchanging
4102 memory is illegal and alias analysis doesn't consider it. */
4103 if (RTX_UNCHANGING_P (canon_mem))
4106 if (XEXP (canon_mem, 0) == frame_pointer_rtx
4107 || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
4108 && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
4109 && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
4112 /* Store a copy of mem, otherwise the address may be scrogged
4113 by find_auto_inc. This matters because insn_dead_p uses
4114 an rtx_equal_p check to determine if two addresses are
4115 the same. This works before find_auto_inc, but fails
4116 after find_auto_inc, causing discrepencies between the
4117 set of live registers calculated during the
4118 calculate_global_regs_live phase and what actually exists
4119 after flow completes, leading to aborts. */
4120 if (flags & PROP_AUTOINC)
4121 mem = shallow_copy_rtx (mem);
4123 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
4124 if (++pbi->mem_set_list_len >= MAX_MEM_SET_LIST_LEN)
4133 /* Release a propagate_block_info struct. */
4136 free_propagate_block_info (pbi)
4137 struct propagate_block_info *pbi;
4139 free_EXPR_LIST_list (&pbi->mem_set_list);
4141 BITMAP_XFREE (pbi->new_set);
4143 #ifdef HAVE_conditional_execution
4144 splay_tree_delete (pbi->reg_cond_dead);
4145 BITMAP_XFREE (pbi->reg_cond_reg);
4148 if (pbi->reg_next_use)
4149 free (pbi->reg_next_use);
4154 /* Compute the registers live at the beginning of a basic block BB from
4155 those live at the end.
4157 When called, REG_LIVE contains those live at the end. On return, it
4158 contains those live at the beginning.
4160 LOCAL_SET, if non-null, will be set with all registers killed
4161 unconditionally by this basic block.
4162 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
4163 killed conditionally by this basic block. If there is any unconditional
4164 set of a register, then the corresponding bit will be set in LOCAL_SET
4165 and cleared in COND_LOCAL_SET.
4166 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
4167 case, the resulting set will be equal to the union of the two sets that
4168 would otherwise be computed. */
4171 propagate_block (bb, live, local_set, cond_local_set, flags)
4175 regset cond_local_set;
4178 struct propagate_block_info *pbi;
4181 pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
4183 if (flags & PROP_REG_INFO)
4187 /* Process the regs live at the end of the block.
4188 Mark them as not local to any one basic block. */
4189 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
4190 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
4193 /* Scan the block an insn at a time from end to beginning. */
4195 for (insn = bb->end;; insn = prev)
4197 /* If this is a call to `setjmp' et al, warn if any
4198 non-volatile datum is live. */
4199 if ((flags & PROP_REG_INFO)
4200 && GET_CODE (insn) == NOTE
4201 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
4202 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
4204 prev = propagate_one_insn (pbi, insn);
4206 if (insn == bb->head)
4210 free_propagate_block_info (pbi);
4213 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
4214 (SET expressions whose destinations are registers dead after the insn).
4215 NEEDED is the regset that says which regs are alive after the insn.
4217 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
4219 If X is the entire body of an insn, NOTES contains the reg notes
4220 pertaining to the insn. */
4223 insn_dead_p (pbi, x, call_ok, notes)
4224 struct propagate_block_info *pbi;
4227 rtx notes ATTRIBUTE_UNUSED;
4229 enum rtx_code code = GET_CODE (x);
4232 /* If flow is invoked after reload, we must take existing AUTO_INC
4233 expresions into account. */
4234 if (reload_completed)
4236 for (; notes; notes = XEXP (notes, 1))
4238 if (REG_NOTE_KIND (notes) == REG_INC)
4240 int regno = REGNO (XEXP (notes, 0));
4242 /* Don't delete insns to set global regs. */
4243 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
4244 || REGNO_REG_SET_P (pbi->reg_live, regno))
4251 /* If setting something that's a reg or part of one,
4252 see if that register's altered value will be live. */
4256 rtx r = SET_DEST (x);
4259 if (GET_CODE (r) == CC0)
4260 return ! pbi->cc0_live;
4263 /* A SET that is a subroutine call cannot be dead. */
4264 if (GET_CODE (SET_SRC (x)) == CALL)
4270 /* Don't eliminate loads from volatile memory or volatile asms. */
4271 else if (volatile_refs_p (SET_SRC (x)))
4274 if (GET_CODE (r) == MEM)
4278 if (MEM_VOLATILE_P (r))
4281 /* Walk the set of memory locations we are currently tracking
4282 and see if one is an identical match to this memory location.
4283 If so, this memory write is dead (remember, we're walking
4284 backwards from the end of the block to the start). Since
4285 rtx_equal_p does not check the alias set or flags, we also
4286 must have the potential for them to conflict (anti_dependence). */
4287 for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
4288 if (anti_dependence (r, XEXP (temp, 0)))
4290 rtx mem = XEXP (temp, 0);
4292 if (rtx_equal_p (mem, r))
4295 /* Check if memory reference matches an auto increment. Only
4296 post increment/decrement or modify are valid. */
4297 if (GET_MODE (mem) == GET_MODE (r)
4298 && (GET_CODE (XEXP (mem, 0)) == POST_DEC
4299 || GET_CODE (XEXP (mem, 0)) == POST_INC
4300 || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
4301 && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
4302 && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
4309 while (GET_CODE (r) == SUBREG
4310 || GET_CODE (r) == STRICT_LOW_PART
4311 || GET_CODE (r) == ZERO_EXTRACT)
4314 if (GET_CODE (r) == REG)
4316 int regno = REGNO (r);
4319 if (REGNO_REG_SET_P (pbi->reg_live, regno))
4322 /* If this is a hard register, verify that subsequent
4323 words are not needed. */
4324 if (regno < FIRST_PSEUDO_REGISTER)
4326 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
4329 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
4333 /* Don't delete insns to set global regs. */
4334 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
4337 /* Make sure insns to set the stack pointer aren't deleted. */
4338 if (regno == STACK_POINTER_REGNUM)
4341 /* ??? These bits might be redundant with the force live bits
4342 in calculate_global_regs_live. We would delete from
4343 sequential sets; whether this actually affects real code
4344 for anything but the stack pointer I don't know. */
4345 /* Make sure insns to set the frame pointer aren't deleted. */
4346 if (regno == FRAME_POINTER_REGNUM
4347 && (! reload_completed || frame_pointer_needed))
4349 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4350 if (regno == HARD_FRAME_POINTER_REGNUM
4351 && (! reload_completed || frame_pointer_needed))
4355 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4356 /* Make sure insns to set arg pointer are never deleted
4357 (if the arg pointer isn't fixed, there will be a USE
4358 for it, so we can treat it normally). */
4359 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
4363 /* Otherwise, the set is dead. */
4369 /* If performing several activities, insn is dead if each activity
4370 is individually dead. Also, CLOBBERs and USEs can be ignored; a
4371 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
4373 else if (code == PARALLEL)
4375 int i = XVECLEN (x, 0);
4377 for (i--; i >= 0; i--)
4378 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
4379 && GET_CODE (XVECEXP (x, 0, i)) != USE
4380 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
4386 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
4387 is not necessarily true for hard registers. */
4388 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
4389 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
4390 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
4393 /* We do not check other CLOBBER or USE here. An insn consisting of just
4394 a CLOBBER or just a USE should not be deleted. */
4398 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
4399 return 1 if the entire library call is dead.
4400 This is true if INSN copies a register (hard or pseudo)
4401 and if the hard return reg of the call insn is dead.
4402 (The caller should have tested the destination of the SET inside
4403 INSN already for death.)
4405 If this insn doesn't just copy a register, then we don't
4406 have an ordinary libcall. In that case, cse could not have
4407 managed to substitute the source for the dest later on,
4408 so we can assume the libcall is dead.
4410 PBI is the block info giving pseudoregs live before this insn.
4411 NOTE is the REG_RETVAL note of the insn. */
4414 libcall_dead_p (pbi, note, insn)
4415 struct propagate_block_info *pbi;
4419 rtx x = single_set (insn);
4423 register rtx r = SET_SRC (x);
4424 if (GET_CODE (r) == REG)
4426 rtx call = XEXP (note, 0);
4430 /* Find the call insn. */
4431 while (call != insn && GET_CODE (call) != CALL_INSN)
4432 call = NEXT_INSN (call);
4434 /* If there is none, do nothing special,
4435 since ordinary death handling can understand these insns. */
4439 /* See if the hard reg holding the value is dead.
4440 If this is a PARALLEL, find the call within it. */
4441 call_pat = PATTERN (call);
4442 if (GET_CODE (call_pat) == PARALLEL)
4444 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
4445 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
4446 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
4449 /* This may be a library call that is returning a value
4450 via invisible pointer. Do nothing special, since
4451 ordinary death handling can understand these insns. */
4455 call_pat = XVECEXP (call_pat, 0, i);
4458 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
4464 /* Return 1 if register REGNO was used before it was set, i.e. if it is
4465 live at function entry. Don't count global register variables, variables
4466 in registers that can be used for function arg passing, or variables in
4467 fixed hard registers. */
4470 regno_uninitialized (regno)
4473 if (n_basic_blocks == 0
4474 || (regno < FIRST_PSEUDO_REGISTER
4475 && (global_regs[regno]
4476 || fixed_regs[regno]
4477 || FUNCTION_ARG_REGNO_P (regno))))
4480 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
4483 /* 1 if register REGNO was alive at a place where `setjmp' was called
4484 and was set more than once or is an argument.
4485 Such regs may be clobbered by `longjmp'. */
4488 regno_clobbered_at_setjmp (regno)
4491 if (n_basic_blocks == 0)
4494 return ((REG_N_SETS (regno) > 1
4495 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
4496 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
4499 /* INSN references memory, possibly using autoincrement addressing modes.
4500 Find any entries on the mem_set_list that need to be invalidated due
4501 to an address change. */
4504 invalidate_mems_from_autoinc (pbi, insn)
4505 struct propagate_block_info *pbi;
4508 rtx note = REG_NOTES (insn);
4509 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
4511 if (REG_NOTE_KIND (note) == REG_INC)
4513 rtx temp = pbi->mem_set_list;
4514 rtx prev = NULL_RTX;
4519 next = XEXP (temp, 1);
4520 if (reg_overlap_mentioned_p (XEXP (note, 0), XEXP (temp, 0)))
4522 /* Splice temp out of list. */
4524 XEXP (prev, 1) = next;
4526 pbi->mem_set_list = next;
4527 free_EXPR_LIST_node (temp);
4528 pbi->mem_set_list_len--;
4538 /* EXP is either a MEM or a REG. Remove any dependant entries
4539 from pbi->mem_set_list. */
4542 invalidate_mems_from_set (pbi, exp)
4543 struct propagate_block_info *pbi;
4546 rtx temp = pbi->mem_set_list;
4547 rtx prev = NULL_RTX;
4552 next = XEXP (temp, 1);
4553 if ((GET_CODE (exp) == MEM
4554 && output_dependence (XEXP (temp, 0), exp))
4555 || (GET_CODE (exp) == REG
4556 && reg_overlap_mentioned_p (exp, XEXP (temp, 0))))
4558 /* Splice this entry out of the list. */
4560 XEXP (prev, 1) = next;
4562 pbi->mem_set_list = next;
4563 free_EXPR_LIST_node (temp);
4564 pbi->mem_set_list_len--;
4572 /* Process the registers that are set within X. Their bits are set to
4573 1 in the regset DEAD, because they are dead prior to this insn.
4575 If INSN is nonzero, it is the insn being processed.
4577 FLAGS is the set of operations to perform. */
4580 mark_set_regs (pbi, x, insn)
4581 struct propagate_block_info *pbi;
4584 rtx cond = NULL_RTX;
4589 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
4591 if (REG_NOTE_KIND (link) == REG_INC)
4592 mark_set_1 (pbi, SET, XEXP (link, 0),
4593 (GET_CODE (x) == COND_EXEC
4594 ? COND_EXEC_TEST (x) : NULL_RTX),
4598 switch (code = GET_CODE (x))
4602 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
4606 cond = COND_EXEC_TEST (x);
4607 x = COND_EXEC_CODE (x);
4613 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
4615 rtx sub = XVECEXP (x, 0, i);
4616 switch (code = GET_CODE (sub))
4619 if (cond != NULL_RTX)
4622 cond = COND_EXEC_TEST (sub);
4623 sub = COND_EXEC_CODE (sub);
4624 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
4630 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
4645 /* Process a single set, which appears in INSN. REG (which may not
4646 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
4647 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
4648 If the set is conditional (because it appear in a COND_EXEC), COND
4649 will be the condition. */
4652 mark_set_1 (pbi, code, reg, cond, insn, flags)
4653 struct propagate_block_info *pbi;
4655 rtx reg, cond, insn;
4658 int regno_first = -1, regno_last = -1;
4659 unsigned long not_dead = 0;
4662 /* Modifying just one hardware register of a multi-reg value or just a
4663 byte field of a register does not mean the value from before this insn
4664 is now dead. Of course, if it was dead after it's unused now. */
4666 switch (GET_CODE (reg))
4669 /* Some targets place small structures in registers for return values of
4670 functions. We have to detect this case specially here to get correct
4671 flow information. */
4672 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
4673 if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
4674 mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
4680 case STRICT_LOW_PART:
4681 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
4683 reg = XEXP (reg, 0);
4684 while (GET_CODE (reg) == SUBREG
4685 || GET_CODE (reg) == ZERO_EXTRACT
4686 || GET_CODE (reg) == SIGN_EXTRACT
4687 || GET_CODE (reg) == STRICT_LOW_PART);
4688 if (GET_CODE (reg) == MEM)
4690 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
4694 regno_last = regno_first = REGNO (reg);
4695 if (regno_first < FIRST_PSEUDO_REGISTER)
4696 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
4700 if (GET_CODE (SUBREG_REG (reg)) == REG)
4702 enum machine_mode outer_mode = GET_MODE (reg);
4703 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
4705 /* Identify the range of registers affected. This is moderately
4706 tricky for hard registers. See alter_subreg. */
4708 regno_last = regno_first = REGNO (SUBREG_REG (reg));
4709 if (regno_first < FIRST_PSEUDO_REGISTER)
4711 regno_first += subreg_regno_offset (regno_first, inner_mode,
4714 regno_last = (regno_first
4715 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
4717 /* Since we've just adjusted the register number ranges, make
4718 sure REG matches. Otherwise some_was_live will be clear
4719 when it shouldn't have been, and we'll create incorrect
4720 REG_UNUSED notes. */
4721 reg = gen_rtx_REG (outer_mode, regno_first);
4725 /* If the number of words in the subreg is less than the number
4726 of words in the full register, we have a well-defined partial
4727 set. Otherwise the high bits are undefined.
4729 This is only really applicable to pseudos, since we just took
4730 care of multi-word hard registers. */
4731 if (((GET_MODE_SIZE (outer_mode)
4732 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
4733 < ((GET_MODE_SIZE (inner_mode)
4734 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
4735 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
4738 reg = SUBREG_REG (reg);
4742 reg = SUBREG_REG (reg);
4749 /* If this set is a MEM, then it kills any aliased writes.
4750 If this set is a REG, then it kills any MEMs which use the reg. */
4751 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
4753 if (GET_CODE (reg) == MEM || GET_CODE (reg) == REG)
4754 invalidate_mems_from_set (pbi, reg);
4756 /* If the memory reference had embedded side effects (autoincrement
4757 address modes. Then we may need to kill some entries on the
4759 if (insn && GET_CODE (reg) == MEM)
4760 invalidate_mems_from_autoinc (pbi, insn);
4762 if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN
4763 && GET_CODE (reg) == MEM && ! side_effects_p (reg)
4764 /* ??? With more effort we could track conditional memory life. */
4766 /* We do not know the size of a BLKmode store, so we do not track
4767 them for redundant store elimination. */
4768 && GET_MODE (reg) != BLKmode
4769 /* There are no REG_INC notes for SP, so we can't assume we'll see
4770 everything that invalidates it. To be safe, don't eliminate any
4771 stores though SP; none of them should be redundant anyway. */
4772 && ! reg_mentioned_p (stack_pointer_rtx, reg))
4775 /* Store a copy of mem, otherwise the address may be
4776 scrogged by find_auto_inc. */
4777 if (flags & PROP_AUTOINC)
4778 reg = shallow_copy_rtx (reg);
4780 pbi->mem_set_list = alloc_EXPR_LIST (0, reg, pbi->mem_set_list);
4781 pbi->mem_set_list_len++;
4785 if (GET_CODE (reg) == REG
4786 && ! (regno_first == FRAME_POINTER_REGNUM
4787 && (! reload_completed || frame_pointer_needed))
4788 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4789 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
4790 && (! reload_completed || frame_pointer_needed))
4792 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4793 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
4797 int some_was_live = 0, some_was_dead = 0;
4799 for (i = regno_first; i <= regno_last; ++i)
4801 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
4804 /* Order of the set operation matters here since both
4805 sets may be the same. */
4806 CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
4807 if (cond != NULL_RTX
4808 && ! REGNO_REG_SET_P (pbi->local_set, i))
4809 SET_REGNO_REG_SET (pbi->cond_local_set, i);
4811 SET_REGNO_REG_SET (pbi->local_set, i);
4813 if (code != CLOBBER)
4814 SET_REGNO_REG_SET (pbi->new_set, i);
4816 some_was_live |= needed_regno;
4817 some_was_dead |= ! needed_regno;
4820 #ifdef HAVE_conditional_execution
4821 /* Consider conditional death in deciding that the register needs
4823 if (some_was_live && ! not_dead
4824 /* The stack pointer is never dead. Well, not strictly true,
4825 but it's very difficult to tell from here. Hopefully
4826 combine_stack_adjustments will fix up the most egregious
4828 && regno_first != STACK_POINTER_REGNUM)
4830 for (i = regno_first; i <= regno_last; ++i)
4831 if (! mark_regno_cond_dead (pbi, i, cond))
4832 not_dead |= ((unsigned long) 1) << (i - regno_first);
4836 /* Additional data to record if this is the final pass. */
4837 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
4838 | PROP_DEATH_NOTES | PROP_AUTOINC))
4841 register int blocknum = pbi->bb->index;
4844 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4846 y = pbi->reg_next_use[regno_first];
4848 /* The next use is no longer next, since a store intervenes. */
4849 for (i = regno_first; i <= regno_last; ++i)
4850 pbi->reg_next_use[i] = 0;
4853 if (flags & PROP_REG_INFO)
4855 for (i = regno_first; i <= regno_last; ++i)
4857 /* Count (weighted) references, stores, etc. This counts a
4858 register twice if it is modified, but that is correct. */
4859 REG_N_SETS (i) += 1;
4860 REG_N_REFS (i) += 1;
4861 REG_FREQ (i) += (optimize_size || !pbi->bb->frequency
4862 ? 1 : pbi->bb->frequency);
4864 /* The insns where a reg is live are normally counted
4865 elsewhere, but we want the count to include the insn
4866 where the reg is set, and the normal counting mechanism
4867 would not count it. */
4868 REG_LIVE_LENGTH (i) += 1;
4871 /* If this is a hard reg, record this function uses the reg. */
4872 if (regno_first < FIRST_PSEUDO_REGISTER)
4874 for (i = regno_first; i <= regno_last; i++)
4875 regs_ever_live[i] = 1;
4879 /* Keep track of which basic blocks each reg appears in. */
4880 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
4881 REG_BASIC_BLOCK (regno_first) = blocknum;
4882 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
4883 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
4887 if (! some_was_dead)
4889 if (flags & PROP_LOG_LINKS)
4891 /* Make a logical link from the next following insn
4892 that uses this register, back to this insn.
4893 The following insns have already been processed.
4895 We don't build a LOG_LINK for hard registers containing
4896 in ASM_OPERANDs. If these registers get replaced,
4897 we might wind up changing the semantics of the insn,
4898 even if reload can make what appear to be valid
4899 assignments later. */
4900 if (y && (BLOCK_NUM (y) == blocknum)
4901 && (regno_first >= FIRST_PSEUDO_REGISTER
4902 || asm_noperands (PATTERN (y)) < 0))
4903 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
4908 else if (! some_was_live)
4910 if (flags & PROP_REG_INFO)
4911 REG_N_DEATHS (regno_first) += 1;
4913 if (flags & PROP_DEATH_NOTES)
4915 /* Note that dead stores have already been deleted
4916 when possible. If we get here, we have found a
4917 dead store that cannot be eliminated (because the
4918 same insn does something useful). Indicate this
4919 by marking the reg being set as dying here. */
4921 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
4926 if (flags & PROP_DEATH_NOTES)
4928 /* This is a case where we have a multi-word hard register
4929 and some, but not all, of the words of the register are
4930 needed in subsequent insns. Write REG_UNUSED notes
4931 for those parts that were not needed. This case should
4934 for (i = regno_first; i <= regno_last; ++i)
4935 if (! REGNO_REG_SET_P (pbi->reg_live, i))
4937 = alloc_EXPR_LIST (REG_UNUSED,
4938 gen_rtx_REG (reg_raw_mode[i], i),
4944 /* Mark the register as being dead. */
4946 /* The stack pointer is never dead. Well, not strictly true,
4947 but it's very difficult to tell from here. Hopefully
4948 combine_stack_adjustments will fix up the most egregious
4950 && regno_first != STACK_POINTER_REGNUM)
4952 for (i = regno_first; i <= regno_last; ++i)
4953 if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
4954 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
4957 else if (GET_CODE (reg) == REG)
4959 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4960 pbi->reg_next_use[regno_first] = 0;
4963 /* If this is the last pass and this is a SCRATCH, show it will be dying
4964 here and count it. */
4965 else if (GET_CODE (reg) == SCRATCH)
4967 if (flags & PROP_DEATH_NOTES)
4969 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
4973 #ifdef HAVE_conditional_execution
4974 /* Mark REGNO conditionally dead.
4975 Return true if the register is now unconditionally dead. */
4978 mark_regno_cond_dead (pbi, regno, cond)
4979 struct propagate_block_info *pbi;
4983 /* If this is a store to a predicate register, the value of the
4984 predicate is changing, we don't know that the predicate as seen
4985 before is the same as that seen after. Flush all dependent
4986 conditions from reg_cond_dead. This will make all such
4987 conditionally live registers unconditionally live. */
4988 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
4989 flush_reg_cond_reg (pbi, regno);
4991 /* If this is an unconditional store, remove any conditional
4992 life that may have existed. */
4993 if (cond == NULL_RTX)
4994 splay_tree_remove (pbi->reg_cond_dead, regno);
4997 splay_tree_node node;
4998 struct reg_cond_life_info *rcli;
5001 /* Otherwise this is a conditional set. Record that fact.
5002 It may have been conditionally used, or there may be a
5003 subsequent set with a complimentary condition. */
5005 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
5008 /* The register was unconditionally live previously.
5009 Record the current condition as the condition under
5010 which it is dead. */
5011 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
5012 rcli->condition = cond;
5013 rcli->stores = cond;
5014 rcli->orig_condition = const0_rtx;
5015 splay_tree_insert (pbi->reg_cond_dead, regno,
5016 (splay_tree_value) rcli);
5018 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5020 /* Not unconditionaly dead. */
5025 /* The register was conditionally live previously.
5026 Add the new condition to the old. */
5027 rcli = (struct reg_cond_life_info *) node->value;
5028 ncond = rcli->condition;
5029 ncond = ior_reg_cond (ncond, cond, 1);
5030 if (rcli->stores == const0_rtx)
5031 rcli->stores = cond;
5032 else if (rcli->stores != const1_rtx)
5033 rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
5035 /* If the register is now unconditionally dead, remove the entry
5036 in the splay_tree. A register is unconditionally dead if the
5037 dead condition ncond is true. A register is also unconditionally
5038 dead if the sum of all conditional stores is an unconditional
5039 store (stores is true), and the dead condition is identically the
5040 same as the original dead condition initialized at the end of
5041 the block. This is a pointer compare, not an rtx_equal_p
5043 if (ncond == const1_rtx
5044 || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
5045 splay_tree_remove (pbi->reg_cond_dead, regno);
5048 rcli->condition = ncond;
5050 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5052 /* Not unconditionaly dead. */
5061 /* Called from splay_tree_delete for pbi->reg_cond_life. */
5064 free_reg_cond_life_info (value)
5065 splay_tree_value value;
5067 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
5071 /* Helper function for flush_reg_cond_reg. */
5074 flush_reg_cond_reg_1 (node, data)
5075 splay_tree_node node;
5078 struct reg_cond_life_info *rcli;
5079 int *xdata = (int *) data;
5080 unsigned int regno = xdata[0];
5082 /* Don't need to search if last flushed value was farther on in
5083 the in-order traversal. */
5084 if (xdata[1] >= (int) node->key)
5087 /* Splice out portions of the expression that refer to regno. */
5088 rcli = (struct reg_cond_life_info *) node->value;
5089 rcli->condition = elim_reg_cond (rcli->condition, regno);
5090 if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
5091 rcli->stores = elim_reg_cond (rcli->stores, regno);
5093 /* If the entire condition is now false, signal the node to be removed. */
5094 if (rcli->condition == const0_rtx)
5096 xdata[1] = node->key;
5099 else if (rcli->condition == const1_rtx)
5105 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
5108 flush_reg_cond_reg (pbi, regno)
5109 struct propagate_block_info *pbi;
5116 while (splay_tree_foreach (pbi->reg_cond_dead,
5117 flush_reg_cond_reg_1, pair) == -1)
5118 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
5120 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
5123 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
5124 For ior/and, the ADD flag determines whether we want to add the new
5125 condition X to the old one unconditionally. If it is zero, we will
5126 only return a new expression if X allows us to simplify part of
5127 OLD, otherwise we return OLD unchanged to the caller.
5128 If ADD is nonzero, we will return a new condition in all cases. The
5129 toplevel caller of one of these functions should always pass 1 for
5133 ior_reg_cond (old, x, add)
5139 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
5141 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
5142 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
5143 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5145 if (GET_CODE (x) == GET_CODE (old)
5146 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5150 return gen_rtx_IOR (0, old, x);
5153 switch (GET_CODE (old))
5156 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
5157 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
5158 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5160 if (op0 == const0_rtx)
5162 if (op1 == const0_rtx)
5164 if (op0 == const1_rtx || op1 == const1_rtx)
5166 if (op0 == XEXP (old, 0))
5167 op0 = gen_rtx_IOR (0, op0, x);
5169 op1 = gen_rtx_IOR (0, op1, x);
5170 return gen_rtx_IOR (0, op0, op1);
5174 return gen_rtx_IOR (0, old, x);
5177 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
5178 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
5179 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5181 if (op0 == const1_rtx)
5183 if (op1 == const1_rtx)
5185 if (op0 == const0_rtx || op1 == const0_rtx)
5187 if (op0 == XEXP (old, 0))
5188 op0 = gen_rtx_IOR (0, op0, x);
5190 op1 = gen_rtx_IOR (0, op1, x);
5191 return gen_rtx_AND (0, op0, op1);
5195 return gen_rtx_IOR (0, old, x);
5198 op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
5199 if (op0 != XEXP (old, 0))
5200 return not_reg_cond (op0);
5203 return gen_rtx_IOR (0, old, x);
5214 enum rtx_code x_code;
5216 if (x == const0_rtx)
5218 else if (x == const1_rtx)
5220 x_code = GET_CODE (x);
5223 if (GET_RTX_CLASS (x_code) == '<'
5224 && GET_CODE (XEXP (x, 0)) == REG)
5226 if (XEXP (x, 1) != const0_rtx)
5229 return gen_rtx_fmt_ee (reverse_condition (x_code),
5230 VOIDmode, XEXP (x, 0), const0_rtx);
5232 return gen_rtx_NOT (0, x);
5236 and_reg_cond (old, x, add)
5242 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
5244 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
5245 && GET_CODE (x) == reverse_condition (GET_CODE (old))
5246 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5248 if (GET_CODE (x) == GET_CODE (old)
5249 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5253 return gen_rtx_AND (0, old, x);
5256 switch (GET_CODE (old))
5259 op0 = and_reg_cond (XEXP (old, 0), x, 0);
5260 op1 = and_reg_cond (XEXP (old, 1), x, 0);
5261 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5263 if (op0 == const0_rtx)
5265 if (op1 == const0_rtx)
5267 if (op0 == const1_rtx || op1 == const1_rtx)
5269 if (op0 == XEXP (old, 0))
5270 op0 = gen_rtx_AND (0, op0, x);
5272 op1 = gen_rtx_AND (0, op1, x);
5273 return gen_rtx_IOR (0, op0, op1);
5277 return gen_rtx_AND (0, old, x);
5280 op0 = and_reg_cond (XEXP (old, 0), x, 0);
5281 op1 = and_reg_cond (XEXP (old, 1), x, 0);
5282 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5284 if (op0 == const1_rtx)
5286 if (op1 == const1_rtx)
5288 if (op0 == const0_rtx || op1 == const0_rtx)
5290 if (op0 == XEXP (old, 0))
5291 op0 = gen_rtx_AND (0, op0, x);
5293 op1 = gen_rtx_AND (0, op1, x);
5294 return gen_rtx_AND (0, op0, op1);
5299 /* If X is identical to one of the existing terms of the AND,
5300 then just return what we already have. */
5301 /* ??? There really should be some sort of recursive check here in
5302 case there are nested ANDs. */
5303 if ((GET_CODE (XEXP (old, 0)) == GET_CODE (x)
5304 && REGNO (XEXP (XEXP (old, 0), 0)) == REGNO (XEXP (x, 0)))
5305 || (GET_CODE (XEXP (old, 1)) == GET_CODE (x)
5306 && REGNO (XEXP (XEXP (old, 1), 0)) == REGNO (XEXP (x, 0))))
5309 return gen_rtx_AND (0, old, x);
5312 op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
5313 if (op0 != XEXP (old, 0))
5314 return not_reg_cond (op0);
5317 return gen_rtx_AND (0, old, x);
5324 /* Given a condition X, remove references to reg REGNO and return the
5325 new condition. The removal will be done so that all conditions
5326 involving REGNO are considered to evaluate to false. This function
5327 is used when the value of REGNO changes. */
5330 elim_reg_cond (x, regno)
5336 if (GET_RTX_CLASS (GET_CODE (x)) == '<')
5338 if (REGNO (XEXP (x, 0)) == regno)
5343 switch (GET_CODE (x))
5346 op0 = elim_reg_cond (XEXP (x, 0), regno);
5347 op1 = elim_reg_cond (XEXP (x, 1), regno);
5348 if (op0 == const0_rtx || op1 == const0_rtx)
5350 if (op0 == const1_rtx)
5352 if (op1 == const1_rtx)
5354 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
5356 return gen_rtx_AND (0, op0, op1);
5359 op0 = elim_reg_cond (XEXP (x, 0), regno);
5360 op1 = elim_reg_cond (XEXP (x, 1), regno);
5361 if (op0 == const1_rtx || op1 == const1_rtx)
5363 if (op0 == const0_rtx)
5365 if (op1 == const0_rtx)
5367 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
5369 return gen_rtx_IOR (0, op0, op1);
5372 op0 = elim_reg_cond (XEXP (x, 0), regno);
5373 if (op0 == const0_rtx)
5375 if (op0 == const1_rtx)
5377 if (op0 != XEXP (x, 0))
5378 return not_reg_cond (op0);
5385 #endif /* HAVE_conditional_execution */
5389 /* Try to substitute the auto-inc expression INC as the address inside
5390 MEM which occurs in INSN. Currently, the address of MEM is an expression
5391 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
5392 that has a single set whose source is a PLUS of INCR_REG and something
5396 attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
5397 struct propagate_block_info *pbi;
5398 rtx inc, insn, mem, incr, incr_reg;
5400 int regno = REGNO (incr_reg);
5401 rtx set = single_set (incr);
5402 rtx q = SET_DEST (set);
5403 rtx y = SET_SRC (set);
5404 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
5406 /* Make sure this reg appears only once in this insn. */
5407 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
5410 if (dead_or_set_p (incr, incr_reg)
5411 /* Mustn't autoinc an eliminable register. */
5412 && (regno >= FIRST_PSEUDO_REGISTER
5413 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
5415 /* This is the simple case. Try to make the auto-inc. If
5416 we can't, we are done. Otherwise, we will do any
5417 needed updates below. */
5418 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
5421 else if (GET_CODE (q) == REG
5422 /* PREV_INSN used here to check the semi-open interval
5424 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
5425 /* We must also check for sets of q as q may be
5426 a call clobbered hard register and there may
5427 be a call between PREV_INSN (insn) and incr. */
5428 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
5430 /* We have *p followed sometime later by q = p+size.
5431 Both p and q must be live afterward,
5432 and q is not used between INSN and its assignment.
5433 Change it to q = p, ...*q..., q = q+size.
5434 Then fall into the usual case. */
5438 emit_move_insn (q, incr_reg);
5439 insns = get_insns ();
5442 if (basic_block_for_insn)
5443 for (temp = insns; temp; temp = NEXT_INSN (temp))
5444 set_block_for_insn (temp, pbi->bb);
5446 /* If we can't make the auto-inc, or can't make the
5447 replacement into Y, exit. There's no point in making
5448 the change below if we can't do the auto-inc and doing
5449 so is not correct in the pre-inc case. */
5452 validate_change (insn, &XEXP (mem, 0), inc, 1);
5453 validate_change (incr, &XEXP (y, opnum), q, 1);
5454 if (! apply_change_group ())
5457 /* We now know we'll be doing this change, so emit the
5458 new insn(s) and do the updates. */
5459 emit_insns_before (insns, insn);
5461 if (pbi->bb->head == insn)
5462 pbi->bb->head = insns;
5464 /* INCR will become a NOTE and INSN won't contain a
5465 use of INCR_REG. If a use of INCR_REG was just placed in
5466 the insn before INSN, make that the next use.
5467 Otherwise, invalidate it. */
5468 if (GET_CODE (PREV_INSN (insn)) == INSN
5469 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
5470 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
5471 pbi->reg_next_use[regno] = PREV_INSN (insn);
5473 pbi->reg_next_use[regno] = 0;
5478 /* REGNO is now used in INCR which is below INSN, but
5479 it previously wasn't live here. If we don't mark
5480 it as live, we'll put a REG_DEAD note for it
5481 on this insn, which is incorrect. */
5482 SET_REGNO_REG_SET (pbi->reg_live, regno);
5484 /* If there are any calls between INSN and INCR, show
5485 that REGNO now crosses them. */
5486 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
5487 if (GET_CODE (temp) == CALL_INSN)
5488 REG_N_CALLS_CROSSED (regno)++;
5493 /* If we haven't returned, it means we were able to make the
5494 auto-inc, so update the status. First, record that this insn
5495 has an implicit side effect. */
5497 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
5499 /* Modify the old increment-insn to simply copy
5500 the already-incremented value of our register. */
5501 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
5504 /* If that makes it a no-op (copying the register into itself) delete
5505 it so it won't appear to be a "use" and a "set" of this
5507 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
5509 /* If the original source was dead, it's dead now. */
5512 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
5514 remove_note (incr, note);
5515 if (XEXP (note, 0) != incr_reg)
5516 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
5519 PUT_CODE (incr, NOTE);
5520 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
5521 NOTE_SOURCE_FILE (incr) = 0;
5524 if (regno >= FIRST_PSEUDO_REGISTER)
5526 /* Count an extra reference to the reg. When a reg is
5527 incremented, spilling it is worse, so we want to make
5528 that less likely. */
5529 REG_FREQ (regno) += (optimize_size || !pbi->bb->frequency
5530 ? 1 : pbi->bb->frequency);
5532 /* Count the increment as a setting of the register,
5533 even though it isn't a SET in rtl. */
5534 REG_N_SETS (regno)++;
5538 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
5542 find_auto_inc (pbi, x, insn)
5543 struct propagate_block_info *pbi;
5547 rtx addr = XEXP (x, 0);
5548 HOST_WIDE_INT offset = 0;
5549 rtx set, y, incr, inc_val;
5551 int size = GET_MODE_SIZE (GET_MODE (x));
5553 if (GET_CODE (insn) == JUMP_INSN)
5556 /* Here we detect use of an index register which might be good for
5557 postincrement, postdecrement, preincrement, or predecrement. */
5559 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
5560 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
5562 if (GET_CODE (addr) != REG)
5565 regno = REGNO (addr);
5567 /* Is the next use an increment that might make auto-increment? */
5568 incr = pbi->reg_next_use[regno];
5569 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
5571 set = single_set (incr);
5572 if (set == 0 || GET_CODE (set) != SET)
5576 if (GET_CODE (y) != PLUS)
5579 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
5580 inc_val = XEXP (y, 1);
5581 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
5582 inc_val = XEXP (y, 0);
5586 if (GET_CODE (inc_val) == CONST_INT)
5588 if (HAVE_POST_INCREMENT
5589 && (INTVAL (inc_val) == size && offset == 0))
5590 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
5592 else if (HAVE_POST_DECREMENT
5593 && (INTVAL (inc_val) == -size && offset == 0))
5594 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
5596 else if (HAVE_PRE_INCREMENT
5597 && (INTVAL (inc_val) == size && offset == size))
5598 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
5600 else if (HAVE_PRE_DECREMENT
5601 && (INTVAL (inc_val) == -size && offset == -size))
5602 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
5604 else if (HAVE_POST_MODIFY_DISP && offset == 0)
5605 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
5606 gen_rtx_PLUS (Pmode,
5609 insn, x, incr, addr);
5611 else if (GET_CODE (inc_val) == REG
5612 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
5616 if (HAVE_POST_MODIFY_REG && offset == 0)
5617 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
5618 gen_rtx_PLUS (Pmode,
5621 insn, x, incr, addr);
5625 #endif /* AUTO_INC_DEC */
5628 mark_used_reg (pbi, reg, cond, insn)
5629 struct propagate_block_info *pbi;
5631 rtx cond ATTRIBUTE_UNUSED;
5634 unsigned int regno_first, regno_last, i;
5635 int some_was_live, some_was_dead, some_not_set;
5637 regno_last = regno_first = REGNO (reg);
5638 if (regno_first < FIRST_PSEUDO_REGISTER)
5639 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
5641 /* Find out if any of this register is live after this instruction. */
5642 some_was_live = some_was_dead = 0;
5643 for (i = regno_first; i <= regno_last; ++i)
5645 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
5646 some_was_live |= needed_regno;
5647 some_was_dead |= ! needed_regno;
5650 /* Find out if any of the register was set this insn. */
5652 for (i = regno_first; i <= regno_last; ++i)
5653 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
5655 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
5657 /* Record where each reg is used, so when the reg is set we know
5658 the next insn that uses it. */
5659 pbi->reg_next_use[regno_first] = insn;
5662 if (pbi->flags & PROP_REG_INFO)
5664 if (regno_first < FIRST_PSEUDO_REGISTER)
5666 /* If this is a register we are going to try to eliminate,
5667 don't mark it live here. If we are successful in
5668 eliminating it, it need not be live unless it is used for
5669 pseudos, in which case it will have been set live when it
5670 was allocated to the pseudos. If the register will not
5671 be eliminated, reload will set it live at that point.
5673 Otherwise, record that this function uses this register. */
5674 /* ??? The PPC backend tries to "eliminate" on the pic
5675 register to itself. This should be fixed. In the mean
5676 time, hack around it. */
5678 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
5679 && (regno_first == FRAME_POINTER_REGNUM
5680 || regno_first == ARG_POINTER_REGNUM)))
5681 for (i = regno_first; i <= regno_last; ++i)
5682 regs_ever_live[i] = 1;
5686 /* Keep track of which basic block each reg appears in. */
5688 register int blocknum = pbi->bb->index;
5689 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
5690 REG_BASIC_BLOCK (regno_first) = blocknum;
5691 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
5692 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
5694 /* Count (weighted) number of uses of each reg. */
5695 REG_FREQ (regno_first)
5696 += (optimize_size || !pbi->bb->frequency ? 1 : pbi->bb->frequency);
5697 REG_N_REFS (regno_first)++;
5701 /* Record and count the insns in which a reg dies. If it is used in
5702 this insn and was dead below the insn then it dies in this insn.
5703 If it was set in this insn, we do not make a REG_DEAD note;
5704 likewise if we already made such a note. */
5705 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
5709 /* Check for the case where the register dying partially
5710 overlaps the register set by this insn. */
5711 if (regno_first != regno_last)
5712 for (i = regno_first; i <= regno_last; ++i)
5713 some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
5715 /* If none of the words in X is needed, make a REG_DEAD note.
5716 Otherwise, we must make partial REG_DEAD notes. */
5717 if (! some_was_live)
5719 if ((pbi->flags & PROP_DEATH_NOTES)
5720 && ! find_regno_note (insn, REG_DEAD, regno_first))
5722 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
5724 if (pbi->flags & PROP_REG_INFO)
5725 REG_N_DEATHS (regno_first)++;
5729 /* Don't make a REG_DEAD note for a part of a register
5730 that is set in the insn. */
5731 for (i = regno_first; i <= regno_last; ++i)
5732 if (! REGNO_REG_SET_P (pbi->reg_live, i)
5733 && ! dead_or_set_regno_p (insn, i))
5735 = alloc_EXPR_LIST (REG_DEAD,
5736 gen_rtx_REG (reg_raw_mode[i], i),
5741 /* Mark the register as being live. */
5742 for (i = regno_first; i <= regno_last; ++i)
5744 SET_REGNO_REG_SET (pbi->reg_live, i);
5746 #ifdef HAVE_conditional_execution
5747 /* If this is a conditional use, record that fact. If it is later
5748 conditionally set, we'll know to kill the register. */
5749 if (cond != NULL_RTX)
5751 splay_tree_node node;
5752 struct reg_cond_life_info *rcli;
5757 node = splay_tree_lookup (pbi->reg_cond_dead, i);
5760 /* The register was unconditionally live previously.
5761 No need to do anything. */
5765 /* The register was conditionally live previously.
5766 Subtract the new life cond from the old death cond. */
5767 rcli = (struct reg_cond_life_info *) node->value;
5768 ncond = rcli->condition;
5769 ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
5771 /* If the register is now unconditionally live,
5772 remove the entry in the splay_tree. */
5773 if (ncond == const0_rtx)
5774 splay_tree_remove (pbi->reg_cond_dead, i);
5777 rcli->condition = ncond;
5778 SET_REGNO_REG_SET (pbi->reg_cond_reg,
5779 REGNO (XEXP (cond, 0)));
5785 /* The register was not previously live at all. Record
5786 the condition under which it is still dead. */
5787 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
5788 rcli->condition = not_reg_cond (cond);
5789 rcli->stores = const0_rtx;
5790 rcli->orig_condition = const0_rtx;
5791 splay_tree_insert (pbi->reg_cond_dead, i,
5792 (splay_tree_value) rcli);
5794 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5797 else if (some_was_live)
5799 /* The register may have been conditionally live previously, but
5800 is now unconditionally live. Remove it from the conditionally
5801 dead list, so that a conditional set won't cause us to think
5803 splay_tree_remove (pbi->reg_cond_dead, i);
5809 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
5810 This is done assuming the registers needed from X are those that
5811 have 1-bits in PBI->REG_LIVE.
5813 INSN is the containing instruction. If INSN is dead, this function
5817 mark_used_regs (pbi, x, cond, insn)
5818 struct propagate_block_info *pbi;
5821 register RTX_CODE code;
5823 int flags = pbi->flags;
5826 code = GET_CODE (x);
5846 /* If we are clobbering a MEM, mark any registers inside the address
5848 if (GET_CODE (XEXP (x, 0)) == MEM)
5849 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
5853 /* Don't bother watching stores to mems if this is not the
5854 final pass. We'll not be deleting dead stores this round. */
5855 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
5857 /* Invalidate the data for the last MEM stored, but only if MEM is
5858 something that can be stored into. */
5859 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
5860 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
5861 /* Needn't clear the memory set list. */
5865 rtx temp = pbi->mem_set_list;
5866 rtx prev = NULL_RTX;
5871 next = XEXP (temp, 1);
5872 if (anti_dependence (XEXP (temp, 0), x))
5874 /* Splice temp out of the list. */
5876 XEXP (prev, 1) = next;
5878 pbi->mem_set_list = next;
5879 free_EXPR_LIST_node (temp);
5880 pbi->mem_set_list_len--;
5888 /* If the memory reference had embedded side effects (autoincrement
5889 address modes. Then we may need to kill some entries on the
5892 invalidate_mems_from_autoinc (pbi, insn);
5896 if (flags & PROP_AUTOINC)
5897 find_auto_inc (pbi, x, insn);
5902 #ifdef CLASS_CANNOT_CHANGE_MODE
5903 if (GET_CODE (SUBREG_REG (x)) == REG
5904 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
5905 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
5906 GET_MODE (SUBREG_REG (x))))
5907 REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
5910 /* While we're here, optimize this case. */
5912 if (GET_CODE (x) != REG)
5917 /* See a register other than being set => mark it as needed. */
5918 mark_used_reg (pbi, x, cond, insn);
5923 register rtx testreg = SET_DEST (x);
5926 /* If storing into MEM, don't show it as being used. But do
5927 show the address as being used. */
5928 if (GET_CODE (testreg) == MEM)
5931 if (flags & PROP_AUTOINC)
5932 find_auto_inc (pbi, testreg, insn);
5934 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
5935 mark_used_regs (pbi, SET_SRC (x), cond, insn);
5939 /* Storing in STRICT_LOW_PART is like storing in a reg
5940 in that this SET might be dead, so ignore it in TESTREG.
5941 but in some other ways it is like using the reg.
5943 Storing in a SUBREG or a bit field is like storing the entire
5944 register in that if the register's value is not used
5945 then this SET is not needed. */
5946 while (GET_CODE (testreg) == STRICT_LOW_PART
5947 || GET_CODE (testreg) == ZERO_EXTRACT
5948 || GET_CODE (testreg) == SIGN_EXTRACT
5949 || GET_CODE (testreg) == SUBREG)
5951 #ifdef CLASS_CANNOT_CHANGE_MODE
5952 if (GET_CODE (testreg) == SUBREG
5953 && GET_CODE (SUBREG_REG (testreg)) == REG
5954 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
5955 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
5956 GET_MODE (testreg)))
5957 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
5960 /* Modifying a single register in an alternate mode
5961 does not use any of the old value. But these other
5962 ways of storing in a register do use the old value. */
5963 if (GET_CODE (testreg) == SUBREG
5964 && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
5969 testreg = XEXP (testreg, 0);
5972 /* If this is a store into a register or group of registers,
5973 recursively scan the value being stored. */
5975 if ((GET_CODE (testreg) == PARALLEL
5976 && GET_MODE (testreg) == BLKmode)
5977 || (GET_CODE (testreg) == REG
5978 && (regno = REGNO (testreg),
5979 ! (regno == FRAME_POINTER_REGNUM
5980 && (! reload_completed || frame_pointer_needed)))
5981 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
5982 && ! (regno == HARD_FRAME_POINTER_REGNUM
5983 && (! reload_completed || frame_pointer_needed))
5985 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
5986 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
5991 mark_used_regs (pbi, SET_DEST (x), cond, insn);
5992 mark_used_regs (pbi, SET_SRC (x), cond, insn);
5999 case UNSPEC_VOLATILE:
6003 /* Traditional and volatile asm instructions must be considered to use
6004 and clobber all hard registers, all pseudo-registers and all of
6005 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
6007 Consider for instance a volatile asm that changes the fpu rounding
6008 mode. An insn should not be moved across this even if it only uses
6009 pseudo-regs because it might give an incorrectly rounded result.
6011 ?!? Unfortunately, marking all hard registers as live causes massive
6012 problems for the register allocator and marking all pseudos as live
6013 creates mountains of uninitialized variable warnings.
6015 So for now, just clear the memory set list and mark any regs
6016 we can find in ASM_OPERANDS as used. */
6017 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
6019 free_EXPR_LIST_list (&pbi->mem_set_list);
6020 pbi->mem_set_list_len = 0;
6023 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
6024 We can not just fall through here since then we would be confused
6025 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
6026 traditional asms unlike their normal usage. */
6027 if (code == ASM_OPERANDS)
6031 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
6032 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
6038 if (cond != NULL_RTX)
6041 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
6043 cond = COND_EXEC_TEST (x);
6044 x = COND_EXEC_CODE (x);
6048 /* We _do_not_ want to scan operands of phi nodes. Operands of
6049 a phi function are evaluated only when control reaches this
6050 block along a particular edge. Therefore, regs that appear
6051 as arguments to phi should not be added to the global live at
6059 /* Recursively scan the operands of this expression. */
6062 register const char *fmt = GET_RTX_FORMAT (code);
6065 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
6069 /* Tail recursive case: save a function call level. */
6075 mark_used_regs (pbi, XEXP (x, i), cond, insn);
6077 else if (fmt[i] == 'E')
6080 for (j = 0; j < XVECLEN (x, i); j++)
6081 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
6090 try_pre_increment_1 (pbi, insn)
6091 struct propagate_block_info *pbi;
6094 /* Find the next use of this reg. If in same basic block,
6095 make it do pre-increment or pre-decrement if appropriate. */
6096 rtx x = single_set (insn);
6097 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
6098 * INTVAL (XEXP (SET_SRC (x), 1)));
6099 int regno = REGNO (SET_DEST (x));
6100 rtx y = pbi->reg_next_use[regno];
6102 && SET_DEST (x) != stack_pointer_rtx
6103 && BLOCK_NUM (y) == BLOCK_NUM (insn)
6104 /* Don't do this if the reg dies, or gets set in y; a standard addressing
6105 mode would be better. */
6106 && ! dead_or_set_p (y, SET_DEST (x))
6107 && try_pre_increment (y, SET_DEST (x), amount))
6109 /* We have found a suitable auto-increment and already changed
6110 insn Y to do it. So flush this increment instruction. */
6111 propagate_block_delete_insn (pbi->bb, insn);
6113 /* Count a reference to this reg for the increment insn we are
6114 deleting. When a reg is incremented, spilling it is worse,
6115 so we want to make that less likely. */
6116 if (regno >= FIRST_PSEUDO_REGISTER)
6118 REG_FREQ (regno) += (optimize_size || !pbi->bb->frequency
6119 ? 1 : pbi->bb->frequency);
6120 REG_N_SETS (regno)++;
6123 /* Flush any remembered memories depending on the value of
6124 the incremented register. */
6125 invalidate_mems_from_set (pbi, SET_DEST (x));
6132 /* Try to change INSN so that it does pre-increment or pre-decrement
6133 addressing on register REG in order to add AMOUNT to REG.
6134 AMOUNT is negative for pre-decrement.
6135 Returns 1 if the change could be made.
6136 This checks all about the validity of the result of modifying INSN. */
6139 try_pre_increment (insn, reg, amount)
6141 HOST_WIDE_INT amount;
6145 /* Nonzero if we can try to make a pre-increment or pre-decrement.
6146 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
6148 /* Nonzero if we can try to make a post-increment or post-decrement.
6149 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
6150 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
6151 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
6154 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
6157 /* From the sign of increment, see which possibilities are conceivable
6158 on this target machine. */
6159 if (HAVE_PRE_INCREMENT && amount > 0)
6161 if (HAVE_POST_INCREMENT && amount > 0)
6164 if (HAVE_PRE_DECREMENT && amount < 0)
6166 if (HAVE_POST_DECREMENT && amount < 0)
6169 if (! (pre_ok || post_ok))
6172 /* It is not safe to add a side effect to a jump insn
6173 because if the incremented register is spilled and must be reloaded
6174 there would be no way to store the incremented value back in memory. */
6176 if (GET_CODE (insn) == JUMP_INSN)
6181 use = find_use_as_address (PATTERN (insn), reg, 0);
6182 if (post_ok && (use == 0 || use == (rtx) 1))
6184 use = find_use_as_address (PATTERN (insn), reg, -amount);
6188 if (use == 0 || use == (rtx) 1)
6191 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
6194 /* See if this combination of instruction and addressing mode exists. */
6195 if (! validate_change (insn, &XEXP (use, 0),
6196 gen_rtx_fmt_e (amount > 0
6197 ? (do_post ? POST_INC : PRE_INC)
6198 : (do_post ? POST_DEC : PRE_DEC),
6202 /* Record that this insn now has an implicit side effect on X. */
6203 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
6207 #endif /* AUTO_INC_DEC */
6209 /* Find the place in the rtx X where REG is used as a memory address.
6210 Return the MEM rtx that so uses it.
6211 If PLUSCONST is nonzero, search instead for a memory address equivalent to
6212 (plus REG (const_int PLUSCONST)).
6214 If such an address does not appear, return 0.
6215 If REG appears more than once, or is used other than in such an address,
6219 find_use_as_address (x, reg, plusconst)
6222 HOST_WIDE_INT plusconst;
6224 enum rtx_code code = GET_CODE (x);
6225 const char *fmt = GET_RTX_FORMAT (code);
6227 register rtx value = 0;
6230 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
6233 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
6234 && XEXP (XEXP (x, 0), 0) == reg
6235 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
6236 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
6239 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
6241 /* If REG occurs inside a MEM used in a bit-field reference,
6242 that is unacceptable. */
6243 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
6244 return (rtx) (HOST_WIDE_INT) 1;
6248 return (rtx) (HOST_WIDE_INT) 1;
6250 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
6254 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
6258 return (rtx) (HOST_WIDE_INT) 1;
6260 else if (fmt[i] == 'E')
6263 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
6265 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
6269 return (rtx) (HOST_WIDE_INT) 1;
6277 /* Write information about registers and basic blocks into FILE.
6278 This is part of making a debugging dump. */
6281 dump_regset (r, outf)
6288 fputs (" (nil)", outf);
6292 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
6294 fprintf (outf, " %d", i);
6295 if (i < FIRST_PSEUDO_REGISTER)
6296 fprintf (outf, " [%s]",
6301 /* Print a human-reaable representation of R on the standard error
6302 stream. This function is designed to be used from within the
6309 dump_regset (r, stderr);
6310 putc ('\n', stderr);
6314 dump_flow_info (file)
6318 static const char * const reg_class_names[] = REG_CLASS_NAMES;
6320 fprintf (file, "%d registers.\n", max_regno);
6321 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
6324 enum reg_class class, altclass;
6325 fprintf (file, "\nRegister %d used %d times across %d insns",
6326 i, REG_N_REFS (i), REG_LIVE_LENGTH (i));
6327 if (REG_BASIC_BLOCK (i) >= 0)
6328 fprintf (file, " in block %d", REG_BASIC_BLOCK (i));
6330 fprintf (file, "; set %d time%s", REG_N_SETS (i),
6331 (REG_N_SETS (i) == 1) ? "" : "s");
6332 if (REG_USERVAR_P (regno_reg_rtx[i]))
6333 fprintf (file, "; user var");
6334 if (REG_N_DEATHS (i) != 1)
6335 fprintf (file, "; dies in %d places", REG_N_DEATHS (i));
6336 if (REG_N_CALLS_CROSSED (i) == 1)
6337 fprintf (file, "; crosses 1 call");
6338 else if (REG_N_CALLS_CROSSED (i))
6339 fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i));
6340 if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
6341 fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
6342 class = reg_preferred_class (i);
6343 altclass = reg_alternate_class (i);
6344 if (class != GENERAL_REGS || altclass != ALL_REGS)
6346 if (altclass == ALL_REGS || class == ALL_REGS)
6347 fprintf (file, "; pref %s", reg_class_names[(int) class]);
6348 else if (altclass == NO_REGS)
6349 fprintf (file, "; %s or none", reg_class_names[(int) class]);
6351 fprintf (file, "; pref %s, else %s",
6352 reg_class_names[(int) class],
6353 reg_class_names[(int) altclass]);
6355 if (REG_POINTER (regno_reg_rtx[i]))
6356 fprintf (file, "; pointer");
6357 fprintf (file, ".\n");
6360 fprintf (file, "\n%d basic blocks, %d edges.\n", n_basic_blocks, n_edges);
6361 for (i = 0; i < n_basic_blocks; i++)
6363 register basic_block bb = BASIC_BLOCK (i);
6366 fprintf (file, "\nBasic block %d: first insn %d, last %d, loop_depth %d, count ",
6367 i, INSN_UID (bb->head), INSN_UID (bb->end), bb->loop_depth);
6368 fprintf (file, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT) bb->count);
6369 fprintf (file, ", freq %i.\n", bb->frequency);
6371 fprintf (file, "Predecessors: ");
6372 for (e = bb->pred; e; e = e->pred_next)
6373 dump_edge_info (file, e, 0);
6375 fprintf (file, "\nSuccessors: ");
6376 for (e = bb->succ; e; e = e->succ_next)
6377 dump_edge_info (file, e, 1);
6379 fprintf (file, "\nRegisters live at start:");
6380 dump_regset (bb->global_live_at_start, file);
6382 fprintf (file, "\nRegisters live at end:");
6383 dump_regset (bb->global_live_at_end, file);
6394 dump_flow_info (stderr);
6398 dump_edge_info (file, e, do_succ)
6403 basic_block side = (do_succ ? e->dest : e->src);
6405 if (side == ENTRY_BLOCK_PTR)
6406 fputs (" ENTRY", file);
6407 else if (side == EXIT_BLOCK_PTR)
6408 fputs (" EXIT", file);
6410 fprintf (file, " %d", side->index);
6413 fprintf (file, " [%.1f%%] ", e->probability * 100.0 / REG_BR_PROB_BASE);
6417 fprintf (file, " count:");
6418 fprintf (file, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT) e->count);
6423 static const char * const bitnames[] = {
6424 "fallthru", "crit", "ab", "abcall", "eh", "fake"
6427 int i, flags = e->flags;
6431 for (i = 0; flags; i++)
6432 if (flags & (1 << i))
6438 if (i < (int) ARRAY_SIZE (bitnames))
6439 fputs (bitnames[i], file);
6441 fprintf (file, "%d", i);
6448 /* Print out one basic block with live information at start and end. */
6459 fprintf (outf, ";; Basic block %d, loop depth %d, count ",
6460 bb->index, bb->loop_depth, bb->count);
6461 fprintf (outf, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT) bb->count);
6464 fputs (";; Predecessors: ", outf);
6465 for (e = bb->pred; e; e = e->pred_next)
6466 dump_edge_info (outf, e, 0);
6469 fputs (";; Registers live at start:", outf);
6470 dump_regset (bb->global_live_at_start, outf);
6473 for (insn = bb->head, last = NEXT_INSN (bb->end);
6475 insn = NEXT_INSN (insn))
6476 print_rtl_single (outf, insn);
6478 fputs (";; Registers live at end:", outf);
6479 dump_regset (bb->global_live_at_end, outf);
6482 fputs (";; Successors: ", outf);
6483 for (e = bb->succ; e; e = e->succ_next)
6484 dump_edge_info (outf, e, 1);
6492 dump_bb (bb, stderr);
6499 dump_bb (BASIC_BLOCK (n), stderr);
6502 /* Like print_rtl, but also print out live information for the start of each
6506 print_rtl_with_bb (outf, rtx_first)
6510 register rtx tmp_rtx;
6513 fprintf (outf, "(nil)\n");
6517 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
6518 int max_uid = get_max_uid ();
6519 basic_block *start = (basic_block *)
6520 xcalloc (max_uid, sizeof (basic_block));
6521 basic_block *end = (basic_block *)
6522 xcalloc (max_uid, sizeof (basic_block));
6523 enum bb_state *in_bb_p = (enum bb_state *)
6524 xcalloc (max_uid, sizeof (enum bb_state));
6526 for (i = n_basic_blocks - 1; i >= 0; i--)
6528 basic_block bb = BASIC_BLOCK (i);
6531 start[INSN_UID (bb->head)] = bb;
6532 end[INSN_UID (bb->end)] = bb;
6533 for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x))
6535 enum bb_state state = IN_MULTIPLE_BB;
6536 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
6538 in_bb_p[INSN_UID (x)] = state;
6545 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
6550 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
6552 fprintf (outf, ";; Start of basic block %d, registers live:",
6554 dump_regset (bb->global_live_at_start, outf);
6558 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
6559 && GET_CODE (tmp_rtx) != NOTE
6560 && GET_CODE (tmp_rtx) != BARRIER)
6561 fprintf (outf, ";; Insn is not within a basic block\n");
6562 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
6563 fprintf (outf, ";; Insn is in multiple basic blocks\n");
6565 did_output = print_rtl_single (outf, tmp_rtx);
6567 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
6569 fprintf (outf, ";; End of basic block %d, registers live:\n",
6571 dump_regset (bb->global_live_at_end, outf);
6584 if (current_function_epilogue_delay_list != 0)
6586 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
6587 for (tmp_rtx = current_function_epilogue_delay_list; tmp_rtx != 0;
6588 tmp_rtx = XEXP (tmp_rtx, 1))
6589 print_rtl_single (outf, XEXP (tmp_rtx, 0));
6593 /* Dump the rtl into the current debugging dump file, then abort. */
6596 print_rtl_and_abort_fcn (file, line, function)
6599 const char *function;
6603 print_rtl_with_bb (rtl_dump_file, get_insns ());
6604 fclose (rtl_dump_file);
6607 fancy_abort (file, line, function);
6610 /* Recompute register set/reference counts immediately prior to register
6613 This avoids problems with set/reference counts changing to/from values
6614 which have special meanings to the register allocators.
6616 Additionally, the reference counts are the primary component used by the
6617 register allocators to prioritize pseudos for allocation to hard regs.
6618 More accurate reference counts generally lead to better register allocation.
6620 F is the first insn to be scanned.
6622 LOOP_STEP denotes how much loop_depth should be incremented per
6623 loop nesting level in order to increase the ref count more for
6624 references in a loop.
6626 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
6627 possibly other information which is used by the register allocators. */
6630 recompute_reg_usage (f, loop_step)
6631 rtx f ATTRIBUTE_UNUSED;
6632 int loop_step ATTRIBUTE_UNUSED;
6634 allocate_reg_life_data ();
6635 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
6638 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
6639 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
6640 of the number of registers that died. */
6643 count_or_remove_death_notes (blocks, kill)
6649 for (i = n_basic_blocks - 1; i >= 0; --i)
6654 if (blocks && ! TEST_BIT (blocks, i))
6657 bb = BASIC_BLOCK (i);
6659 for (insn = bb->head;; insn = NEXT_INSN (insn))
6663 rtx *pprev = ®_NOTES (insn);
6668 switch (REG_NOTE_KIND (link))
6671 if (GET_CODE (XEXP (link, 0)) == REG)
6673 rtx reg = XEXP (link, 0);
6676 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
6679 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
6687 rtx next = XEXP (link, 1);
6688 free_EXPR_LIST_node (link);
6689 *pprev = link = next;
6695 pprev = &XEXP (link, 1);
6702 if (insn == bb->end)
6711 /* Update insns block within BB. */
6714 update_bb_for_insn (bb)
6719 if (! basic_block_for_insn)
6722 for (insn = bb->head; ; insn = NEXT_INSN (insn))
6724 set_block_for_insn (insn, bb);
6726 if (insn == bb->end)
6732 /* Record INSN's block as BB. */
6735 set_block_for_insn (insn, bb)
6739 size_t uid = INSN_UID (insn);
6740 if (uid >= basic_block_for_insn->num_elements)
6744 /* Add one-eighth the size so we don't keep calling xrealloc. */
6745 new_size = uid + (uid + 7) / 8;
6747 VARRAY_GROW (basic_block_for_insn, new_size);
6749 VARRAY_BB (basic_block_for_insn, uid) = bb;
6752 /* When a new insn has been inserted into an existing block, it will
6753 sometimes emit more than a single insn. This routine will set the
6754 block number for the specified insn, and look backwards in the insn
6755 chain to see if there are any other uninitialized insns immediately
6756 previous to this one, and set the block number for them too. */
6759 set_block_for_new_insns (insn, bb)
6763 set_block_for_insn (insn, bb);
6765 /* Scan the previous instructions setting the block number until we find
6766 an instruction that has the block number set, or we find a note
6768 for (insn = PREV_INSN (insn); insn != NULL_RTX; insn = PREV_INSN (insn))
6770 if (GET_CODE (insn) == NOTE)
6772 if (INSN_UID (insn) >= basic_block_for_insn->num_elements
6773 || BLOCK_FOR_INSN (insn) == 0)
6774 set_block_for_insn (insn, bb);
6780 /* Verify the CFG consistency. This function check some CFG invariants and
6781 aborts when something is wrong. Hope that this function will help to
6782 convert many optimization passes to preserve CFG consistent.
6784 Currently it does following checks:
6786 - test head/end pointers
6787 - overlapping of basic blocks
6788 - edge list corectness
6789 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
6790 - tails of basic blocks (ensure that boundary is necesary)
6791 - scans body of the basic block for JUMP_INSN, CODE_LABEL
6792 and NOTE_INSN_BASIC_BLOCK
6793 - check that all insns are in the basic blocks
6794 (except the switch handling code, barriers and notes)
6795 - check that all returns are followed by barriers
6797 In future it can be extended check a lot of other stuff as well
6798 (reachability of basic blocks, life information, etc. etc.). */
6803 const int max_uid = get_max_uid ();
6804 const rtx rtx_first = get_insns ();
6805 rtx last_head = get_last_insn ();
6806 basic_block *bb_info;
6808 int i, last_bb_num_seen, num_bb_notes, err = 0;
6810 bb_info = (basic_block *) xcalloc (max_uid, sizeof (basic_block));
6812 for (i = n_basic_blocks - 1; i >= 0; i--)
6814 basic_block bb = BASIC_BLOCK (i);
6815 rtx head = bb->head;
6818 /* Verify the end of the basic block is in the INSN chain. */
6819 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
6824 error ("End insn %d for block %d not found in the insn stream.",
6825 INSN_UID (end), bb->index);
6829 /* Work backwards from the end to the head of the basic block
6830 to verify the head is in the RTL chain. */
6831 for (; x != NULL_RTX; x = PREV_INSN (x))
6833 /* While walking over the insn chain, verify insns appear
6834 in only one basic block and initialize the BB_INFO array
6835 used by other passes. */
6836 if (bb_info[INSN_UID (x)] != NULL)
6838 error ("Insn %d is in multiple basic blocks (%d and %d)",
6839 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
6842 bb_info[INSN_UID (x)] = bb;
6849 error ("Head insn %d for block %d not found in the insn stream.",
6850 INSN_UID (head), bb->index);
6857 /* Now check the basic blocks (boundaries etc.) */
6858 for (i = n_basic_blocks - 1; i >= 0; i--)
6860 basic_block bb = BASIC_BLOCK (i);
6861 /* Check corectness of edge lists */
6870 "verify_flow_info: Basic block %d succ edge is corrupted\n",
6872 fprintf (stderr, "Predecessor: ");
6873 dump_edge_info (stderr, e, 0);
6874 fprintf (stderr, "\nSuccessor: ");
6875 dump_edge_info (stderr, e, 1);
6879 if (e->dest != EXIT_BLOCK_PTR)
6881 edge e2 = e->dest->pred;
6882 while (e2 && e2 != e)
6886 error ("Basic block %i edge lists are corrupted", bb->index);
6898 error ("Basic block %d pred edge is corrupted", bb->index);
6899 fputs ("Predecessor: ", stderr);
6900 dump_edge_info (stderr, e, 0);
6901 fputs ("\nSuccessor: ", stderr);
6902 dump_edge_info (stderr, e, 1);
6903 fputc ('\n', stderr);
6906 if (e->src != ENTRY_BLOCK_PTR)
6908 edge e2 = e->src->succ;
6909 while (e2 && e2 != e)
6913 error ("Basic block %i edge lists are corrupted", bb->index);
6920 /* OK pointers are correct. Now check the header of basic
6921 block. It ought to contain optional CODE_LABEL followed
6922 by NOTE_BASIC_BLOCK. */
6924 if (GET_CODE (x) == CODE_LABEL)
6928 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
6934 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
6936 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d\n",
6943 /* Do checks for empty blocks here */
6950 if (NOTE_INSN_BASIC_BLOCK_P (x))
6952 error ("NOTE_INSN_BASIC_BLOCK %d in the middle of basic block %d",
6953 INSN_UID (x), bb->index);
6960 if (GET_CODE (x) == JUMP_INSN
6961 || GET_CODE (x) == CODE_LABEL
6962 || GET_CODE (x) == BARRIER)
6964 error ("In basic block %d:", bb->index);
6965 fatal_insn ("Flow control insn inside a basic block", x);
6973 last_bb_num_seen = -1;
6978 if (NOTE_INSN_BASIC_BLOCK_P (x))
6980 basic_block bb = NOTE_BASIC_BLOCK (x);
6982 if (bb->index != last_bb_num_seen + 1)
6983 /* Basic blocks not numbered consecutively. */
6986 last_bb_num_seen = bb->index;
6989 if (!bb_info[INSN_UID (x)])
6991 switch (GET_CODE (x))
6998 /* An addr_vec is placed outside any block block. */
7000 && GET_CODE (NEXT_INSN (x)) == JUMP_INSN
7001 && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
7002 || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
7007 /* But in any case, non-deletable labels can appear anywhere. */
7011 fatal_insn ("Insn outside basic block", x);
7016 && GET_CODE (x) == JUMP_INSN
7017 && returnjump_p (x) && ! condjump_p (x)
7018 && ! (NEXT_INSN (x) && GET_CODE (NEXT_INSN (x)) == BARRIER))
7019 fatal_insn ("Return not followed by barrier", x);
7024 if (num_bb_notes != n_basic_blocks)
7026 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
7027 num_bb_notes, n_basic_blocks);
7036 /* Functions to access an edge list with a vector representation.
7037 Enough data is kept such that given an index number, the
7038 pred and succ that edge represents can be determined, or
7039 given a pred and a succ, its index number can be returned.
7040 This allows algorithms which consume a lot of memory to
7041 represent the normally full matrix of edge (pred,succ) with a
7042 single indexed vector, edge (EDGE_INDEX (pred, succ)), with no
7043 wasted space in the client code due to sparse flow graphs. */
7045 /* This functions initializes the edge list. Basically the entire
7046 flowgraph is processed, and all edges are assigned a number,
7047 and the data structure is filled in. */
7052 struct edge_list *elist;
7058 block_count = n_basic_blocks + 2; /* Include the entry and exit blocks. */
7062 /* Determine the number of edges in the flow graph by counting successor
7063 edges on each basic block. */
7064 for (x = 0; x < n_basic_blocks; x++)
7066 basic_block bb = BASIC_BLOCK (x);
7068 for (e = bb->succ; e; e = e->succ_next)
7071 /* Don't forget successors of the entry block. */
7072 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
7075 elist = (struct edge_list *) xmalloc (sizeof (struct edge_list));
7076 elist->num_blocks = block_count;
7077 elist->num_edges = num_edges;
7078 elist->index_to_edge = (edge *) xmalloc (sizeof (edge) * num_edges);
7082 /* Follow successors of the entry block, and register these edges. */
7083 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
7085 elist->index_to_edge[num_edges] = e;
7089 for (x = 0; x < n_basic_blocks; x++)
7091 basic_block bb = BASIC_BLOCK (x);
7093 /* Follow all successors of blocks, and register these edges. */
7094 for (e = bb->succ; e; e = e->succ_next)
7096 elist->index_to_edge[num_edges] = e;
7103 /* This function free's memory associated with an edge list. */
7106 free_edge_list (elist)
7107 struct edge_list *elist;
7111 free (elist->index_to_edge);
7116 /* This function provides debug output showing an edge list. */
7119 print_edge_list (f, elist)
7121 struct edge_list *elist;
7124 fprintf (f, "Compressed edge list, %d BBs + entry & exit, and %d edges\n",
7125 elist->num_blocks - 2, elist->num_edges);
7127 for (x = 0; x < elist->num_edges; x++)
7129 fprintf (f, " %-4d - edge(", x);
7130 if (INDEX_EDGE_PRED_BB (elist, x) == ENTRY_BLOCK_PTR)
7131 fprintf (f, "entry,");
7133 fprintf (f, "%d,", INDEX_EDGE_PRED_BB (elist, x)->index);
7135 if (INDEX_EDGE_SUCC_BB (elist, x) == EXIT_BLOCK_PTR)
7136 fprintf (f, "exit)\n");
7138 fprintf (f, "%d)\n", INDEX_EDGE_SUCC_BB (elist, x)->index);
7142 /* This function provides an internal consistency check of an edge list,
7143 verifying that all edges are present, and that there are no
7147 verify_edge_list (f, elist)
7149 struct edge_list *elist;
7151 int x, pred, succ, index;
7154 for (x = 0; x < n_basic_blocks; x++)
7156 basic_block bb = BASIC_BLOCK (x);
7158 for (e = bb->succ; e; e = e->succ_next)
7160 pred = e->src->index;
7161 succ = e->dest->index;
7162 index = EDGE_INDEX (elist, e->src, e->dest);
7163 if (index == EDGE_INDEX_NO_EDGE)
7165 fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
7168 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
7169 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
7170 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
7171 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
7172 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
7173 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
7176 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
7178 pred = e->src->index;
7179 succ = e->dest->index;
7180 index = EDGE_INDEX (elist, e->src, e->dest);
7181 if (index == EDGE_INDEX_NO_EDGE)
7183 fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
7186 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
7187 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
7188 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
7189 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
7190 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
7191 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
7193 /* We've verified that all the edges are in the list, no lets make sure
7194 there are no spurious edges in the list. */
7196 for (pred = 0; pred < n_basic_blocks; pred++)
7197 for (succ = 0; succ < n_basic_blocks; succ++)
7199 basic_block p = BASIC_BLOCK (pred);
7200 basic_block s = BASIC_BLOCK (succ);
7204 for (e = p->succ; e; e = e->succ_next)
7210 for (e = s->pred; e; e = e->pred_next)
7216 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
7217 == EDGE_INDEX_NO_EDGE && found_edge != 0)
7218 fprintf (f, "*** Edge (%d, %d) appears to not have an index\n",
7220 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
7221 != EDGE_INDEX_NO_EDGE && found_edge == 0)
7222 fprintf (f, "*** Edge (%d, %d) has index %d, but there is no edge\n",
7223 pred, succ, EDGE_INDEX (elist, BASIC_BLOCK (pred),
7224 BASIC_BLOCK (succ)));
7226 for (succ = 0; succ < n_basic_blocks; succ++)
7228 basic_block p = ENTRY_BLOCK_PTR;
7229 basic_block s = BASIC_BLOCK (succ);
7233 for (e = p->succ; e; e = e->succ_next)
7239 for (e = s->pred; e; e = e->pred_next)
7245 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
7246 == EDGE_INDEX_NO_EDGE && found_edge != 0)
7247 fprintf (f, "*** Edge (entry, %d) appears to not have an index\n",
7249 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
7250 != EDGE_INDEX_NO_EDGE && found_edge == 0)
7251 fprintf (f, "*** Edge (entry, %d) has index %d, but no edge exists\n",
7252 succ, EDGE_INDEX (elist, ENTRY_BLOCK_PTR,
7253 BASIC_BLOCK (succ)));
7255 for (pred = 0; pred < n_basic_blocks; pred++)
7257 basic_block p = BASIC_BLOCK (pred);
7258 basic_block s = EXIT_BLOCK_PTR;
7262 for (e = p->succ; e; e = e->succ_next)
7268 for (e = s->pred; e; e = e->pred_next)
7274 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
7275 == EDGE_INDEX_NO_EDGE && found_edge != 0)
7276 fprintf (f, "*** Edge (%d, exit) appears to not have an index\n",
7278 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
7279 != EDGE_INDEX_NO_EDGE && found_edge == 0)
7280 fprintf (f, "*** Edge (%d, exit) has index %d, but no edge exists\n",
7281 pred, EDGE_INDEX (elist, BASIC_BLOCK (pred),
7286 /* This routine will determine what, if any, edge there is between
7287 a specified predecessor and successor. */
7290 find_edge_index (edge_list, pred, succ)
7291 struct edge_list *edge_list;
7292 basic_block pred, succ;
7295 for (x = 0; x < NUM_EDGES (edge_list); x++)
7297 if (INDEX_EDGE_PRED_BB (edge_list, x) == pred
7298 && INDEX_EDGE_SUCC_BB (edge_list, x) == succ)
7301 return (EDGE_INDEX_NO_EDGE);
7304 /* This function will remove an edge from the flow graph. */
7310 edge last_pred = NULL;
7311 edge last_succ = NULL;
7313 basic_block src, dest;
7316 for (tmp = src->succ; tmp && tmp != e; tmp = tmp->succ_next)
7322 last_succ->succ_next = e->succ_next;
7324 src->succ = e->succ_next;
7326 for (tmp = dest->pred; tmp && tmp != e; tmp = tmp->pred_next)
7332 last_pred->pred_next = e->pred_next;
7334 dest->pred = e->pred_next;
7340 /* This routine will remove any fake successor edges for a basic block.
7341 When the edge is removed, it is also removed from whatever predecessor
7345 remove_fake_successors (bb)
7349 for (e = bb->succ; e;)
7353 if ((tmp->flags & EDGE_FAKE) == EDGE_FAKE)
7358 /* This routine will remove all fake edges from the flow graph. If
7359 we remove all fake successors, it will automatically remove all
7360 fake predecessors. */
7363 remove_fake_edges ()
7367 for (x = 0; x < n_basic_blocks; x++)
7368 remove_fake_successors (BASIC_BLOCK (x));
7370 /* We've handled all successors except the entry block's. */
7371 remove_fake_successors (ENTRY_BLOCK_PTR);
7374 /* This function will add a fake edge between any block which has no
7375 successors, and the exit block. Some data flow equations require these
7379 add_noreturn_fake_exit_edges ()
7383 for (x = 0; x < n_basic_blocks; x++)
7384 if (BASIC_BLOCK (x)->succ == NULL)
7385 make_edge (NULL, BASIC_BLOCK (x), EXIT_BLOCK_PTR, EDGE_FAKE);
7388 /* This function adds a fake edge between any infinite loops to the
7389 exit block. Some optimizations require a path from each node to
7392 See also Morgan, Figure 3.10, pp. 82-83.
7394 The current implementation is ugly, not attempting to minimize the
7395 number of inserted fake edges. To reduce the number of fake edges
7396 to insert, add fake edges from _innermost_ loops containing only
7397 nodes not reachable from the exit block. */
7400 connect_infinite_loops_to_exit ()
7402 basic_block unvisited_block;
7404 /* Perform depth-first search in the reverse graph to find nodes
7405 reachable from the exit block. */
7406 struct depth_first_search_dsS dfs_ds;
7408 flow_dfs_compute_reverse_init (&dfs_ds);
7409 flow_dfs_compute_reverse_add_bb (&dfs_ds, EXIT_BLOCK_PTR);
7411 /* Repeatedly add fake edges, updating the unreachable nodes. */
7414 unvisited_block = flow_dfs_compute_reverse_execute (&dfs_ds);
7415 if (!unvisited_block)
7417 make_edge (NULL, unvisited_block, EXIT_BLOCK_PTR, EDGE_FAKE);
7418 flow_dfs_compute_reverse_add_bb (&dfs_ds, unvisited_block);
7421 flow_dfs_compute_reverse_finish (&dfs_ds);
7426 /* Redirect an edge's successor from one block to another. */
7429 redirect_edge_succ (e, new_succ)
7431 basic_block new_succ;
7435 /* Disconnect the edge from the old successor block. */
7436 for (pe = &e->dest->pred; *pe != e; pe = &(*pe)->pred_next)
7438 *pe = (*pe)->pred_next;
7440 /* Reconnect the edge to the new successor block. */
7441 e->pred_next = new_succ->pred;
7446 /* Redirect an edge's predecessor from one block to another. */
7449 redirect_edge_pred (e, new_pred)
7451 basic_block new_pred;
7455 /* Disconnect the edge from the old predecessor block. */
7456 for (pe = &e->src->succ; *pe != e; pe = &(*pe)->succ_next)
7458 *pe = (*pe)->succ_next;
7460 /* Reconnect the edge to the new predecessor block. */
7461 e->succ_next = new_pred->succ;
7466 /* Dump the list of basic blocks in the bitmap NODES. */
7469 flow_nodes_print (str, nodes, file)
7471 const sbitmap nodes;
7479 fprintf (file, "%s { ", str);
7480 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {fprintf (file, "%d ", node);});
7481 fputs ("}\n", file);
7485 /* Dump the list of edges in the array EDGE_LIST. */
7488 flow_edge_list_print (str, edge_list, num_edges, file)
7490 const edge *edge_list;
7499 fprintf (file, "%s { ", str);
7500 for (i = 0; i < num_edges; i++)
7501 fprintf (file, "%d->%d ", edge_list[i]->src->index,
7502 edge_list[i]->dest->index);
7503 fputs ("}\n", file);
7507 /* Dump loop related CFG information. */
7510 flow_loops_cfg_dump (loops, file)
7511 const struct loops *loops;
7516 if (! loops->num || ! file || ! loops->cfg.dom)
7519 for (i = 0; i < n_basic_blocks; i++)
7523 fprintf (file, ";; %d succs { ", i);
7524 for (succ = BASIC_BLOCK (i)->succ; succ; succ = succ->succ_next)
7525 fprintf (file, "%d ", succ->dest->index);
7526 flow_nodes_print ("} dom", loops->cfg.dom[i], file);
7529 /* Dump the DFS node order. */
7530 if (loops->cfg.dfs_order)
7532 fputs (";; DFS order: ", file);
7533 for (i = 0; i < n_basic_blocks; i++)
7534 fprintf (file, "%d ", loops->cfg.dfs_order[i]);
7537 /* Dump the reverse completion node order. */
7538 if (loops->cfg.rc_order)
7540 fputs (";; RC order: ", file);
7541 for (i = 0; i < n_basic_blocks; i++)
7542 fprintf (file, "%d ", loops->cfg.rc_order[i]);
7547 /* Return non-zero if the nodes of LOOP are a subset of OUTER. */
7550 flow_loop_nested_p (outer, loop)
7554 return sbitmap_a_subset_b_p (loop->nodes, outer->nodes);
7558 /* Dump the loop information specified by LOOP to the stream FILE
7559 using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
7561 flow_loop_dump (loop, file, loop_dump_aux, verbose)
7562 const struct loop *loop;
7564 void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
7567 if (! loop || ! loop->header)
7570 fprintf (file, ";;\n;; Loop %d (%d to %d):%s%s\n",
7571 loop->num, INSN_UID (loop->first->head),
7572 INSN_UID (loop->last->end),
7573 loop->shared ? " shared" : "",
7574 loop->invalid ? " invalid" : "");
7575 fprintf (file, ";; header %d, latch %d, pre-header %d, first %d, last %d\n",
7576 loop->header->index, loop->latch->index,
7577 loop->pre_header ? loop->pre_header->index : -1,
7578 loop->first->index, loop->last->index);
7579 fprintf (file, ";; depth %d, level %d, outer %ld\n",
7580 loop->depth, loop->level,
7581 (long) (loop->outer ? loop->outer->num : -1));
7583 if (loop->pre_header_edges)
7584 flow_edge_list_print (";; pre-header edges", loop->pre_header_edges,
7585 loop->num_pre_header_edges, file);
7586 flow_edge_list_print (";; entry edges", loop->entry_edges,
7587 loop->num_entries, file);
7588 fprintf (file, ";; %d", loop->num_nodes);
7589 flow_nodes_print (" nodes", loop->nodes, file);
7590 flow_edge_list_print (";; exit edges", loop->exit_edges,
7591 loop->num_exits, file);
7592 if (loop->exits_doms)
7593 flow_nodes_print (";; exit doms", loop->exits_doms, file);
7595 loop_dump_aux (loop, file, verbose);
7599 /* Dump the loop information specified by LOOPS to the stream FILE,
7600 using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
7602 flow_loops_dump (loops, file, loop_dump_aux, verbose)
7603 const struct loops *loops;
7605 void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
7611 num_loops = loops->num;
7612 if (! num_loops || ! file)
7615 fprintf (file, ";; %d loops found, %d levels\n",
7616 num_loops, loops->levels);
7618 for (i = 0; i < num_loops; i++)
7620 struct loop *loop = &loops->array[i];
7622 flow_loop_dump (loop, file, loop_dump_aux, verbose);
7628 for (j = 0; j < i; j++)
7630 struct loop *oloop = &loops->array[j];
7632 if (loop->header == oloop->header)
7637 smaller = loop->num_nodes < oloop->num_nodes;
7639 /* If the union of LOOP and OLOOP is different than
7640 the larger of LOOP and OLOOP then LOOP and OLOOP
7641 must be disjoint. */
7642 disjoint = ! flow_loop_nested_p (smaller ? loop : oloop,
7643 smaller ? oloop : loop);
7645 ";; loop header %d shared by loops %d, %d %s\n",
7646 loop->header->index, i, j,
7647 disjoint ? "disjoint" : "nested");
7654 flow_loops_cfg_dump (loops, file);
7658 /* Free all the memory allocated for LOOPS. */
7661 flow_loops_free (loops)
7662 struct loops *loops;
7671 /* Free the loop descriptors. */
7672 for (i = 0; i < loops->num; i++)
7674 struct loop *loop = &loops->array[i];
7676 if (loop->pre_header_edges)
7677 free (loop->pre_header_edges);
7679 sbitmap_free (loop->nodes);
7680 if (loop->entry_edges)
7681 free (loop->entry_edges);
7682 if (loop->exit_edges)
7683 free (loop->exit_edges);
7684 if (loop->exits_doms)
7685 sbitmap_free (loop->exits_doms);
7687 free (loops->array);
7688 loops->array = NULL;
7691 sbitmap_vector_free (loops->cfg.dom);
7692 if (loops->cfg.dfs_order)
7693 free (loops->cfg.dfs_order);
7695 if (loops->shared_headers)
7696 sbitmap_free (loops->shared_headers);
7701 /* Find the entry edges into the loop with header HEADER and nodes
7702 NODES and store in ENTRY_EDGES array. Return the number of entry
7703 edges from the loop. */
7706 flow_loop_entry_edges_find (header, nodes, entry_edges)
7708 const sbitmap nodes;
7714 *entry_edges = NULL;
7717 for (e = header->pred; e; e = e->pred_next)
7719 basic_block src = e->src;
7721 if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
7728 *entry_edges = (edge *) xmalloc (num_entries * sizeof (edge *));
7731 for (e = header->pred; e; e = e->pred_next)
7733 basic_block src = e->src;
7735 if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
7736 (*entry_edges)[num_entries++] = e;
7743 /* Find the exit edges from the loop using the bitmap of loop nodes
7744 NODES and store in EXIT_EDGES array. Return the number of
7745 exit edges from the loop. */
7748 flow_loop_exit_edges_find (nodes, exit_edges)
7749 const sbitmap nodes;
7758 /* Check all nodes within the loop to see if there are any
7759 successors not in the loop. Note that a node may have multiple
7760 exiting edges ????? A node can have one jumping edge and one fallthru
7761 edge so only one of these can exit the loop. */
7763 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
7764 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
7766 basic_block dest = e->dest;
7768 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
7776 *exit_edges = (edge *) xmalloc (num_exits * sizeof (edge *));
7778 /* Store all exiting edges into an array. */
7780 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
7781 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
7783 basic_block dest = e->dest;
7785 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
7786 (*exit_edges)[num_exits++] = e;
7794 /* Find the nodes contained within the loop with header HEADER and
7795 latch LATCH and store in NODES. Return the number of nodes within
7799 flow_loop_nodes_find (header, latch, nodes)
7808 stack = (basic_block *) xmalloc (n_basic_blocks * sizeof (basic_block));
7811 /* Start with only the loop header in the set of loop nodes. */
7812 sbitmap_zero (nodes);
7813 SET_BIT (nodes, header->index);
7815 header->loop_depth++;
7817 /* Push the loop latch on to the stack. */
7818 if (! TEST_BIT (nodes, latch->index))
7820 SET_BIT (nodes, latch->index);
7821 latch->loop_depth++;
7823 stack[sp++] = latch;
7832 for (e = node->pred; e; e = e->pred_next)
7834 basic_block ancestor = e->src;
7836 /* If each ancestor not marked as part of loop, add to set of
7837 loop nodes and push on to stack. */
7838 if (ancestor != ENTRY_BLOCK_PTR
7839 && ! TEST_BIT (nodes, ancestor->index))
7841 SET_BIT (nodes, ancestor->index);
7842 ancestor->loop_depth++;
7844 stack[sp++] = ancestor;
7852 /* Compute the depth first search order and store in the array
7853 DFS_ORDER if non-zero, marking the nodes visited in VISITED. If
7854 RC_ORDER is non-zero, return the reverse completion number for each
7855 node. Returns the number of nodes visited. A depth first search
7856 tries to get as far away from the starting point as quickly as
7860 flow_depth_first_order_compute (dfs_order, rc_order)
7867 int rcnum = n_basic_blocks - 1;
7870 /* Allocate stack for back-tracking up CFG. */
7871 stack = (edge *) xmalloc ((n_basic_blocks + 1) * sizeof (edge));
7874 /* Allocate bitmap to track nodes that have been visited. */
7875 visited = sbitmap_alloc (n_basic_blocks);
7877 /* None of the nodes in the CFG have been visited yet. */
7878 sbitmap_zero (visited);
7880 /* Push the first edge on to the stack. */
7881 stack[sp++] = ENTRY_BLOCK_PTR->succ;
7889 /* Look at the edge on the top of the stack. */
7894 /* Check if the edge destination has been visited yet. */
7895 if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index))
7897 /* Mark that we have visited the destination. */
7898 SET_BIT (visited, dest->index);
7901 dfs_order[dfsnum++] = dest->index;
7905 /* Since the DEST node has been visited for the first
7906 time, check its successors. */
7907 stack[sp++] = dest->succ;
7911 /* There are no successors for the DEST node so assign
7912 its reverse completion number. */
7914 rc_order[rcnum--] = dest->index;
7919 if (! e->succ_next && src != ENTRY_BLOCK_PTR)
7921 /* There are no more successors for the SRC node
7922 so assign its reverse completion number. */
7924 rc_order[rcnum--] = src->index;
7928 stack[sp - 1] = e->succ_next;
7935 sbitmap_free (visited);
7937 /* The number of nodes visited should not be greater than
7939 if (dfsnum > n_basic_blocks)
7942 /* There are some nodes left in the CFG that are unreachable. */
7943 if (dfsnum < n_basic_blocks)
7948 /* Compute the depth first search order on the _reverse_ graph and
7949 store in the array DFS_ORDER, marking the nodes visited in VISITED.
7950 Returns the number of nodes visited.
7952 The computation is split into three pieces:
7954 flow_dfs_compute_reverse_init () creates the necessary data
7957 flow_dfs_compute_reverse_add_bb () adds a basic block to the data
7958 structures. The block will start the search.
7960 flow_dfs_compute_reverse_execute () continues (or starts) the
7961 search using the block on the top of the stack, stopping when the
7964 flow_dfs_compute_reverse_finish () destroys the necessary data
7967 Thus, the user will probably call ..._init(), call ..._add_bb() to
7968 add a beginning basic block to the stack, call ..._execute(),
7969 possibly add another bb to the stack and again call ..._execute(),
7970 ..., and finally call _finish(). */
7972 /* Initialize the data structures used for depth-first search on the
7973 reverse graph. If INITIALIZE_STACK is nonzero, the exit block is
7974 added to the basic block stack. DATA is the current depth-first
7975 search context. If INITIALIZE_STACK is non-zero, there is an
7976 element on the stack. */
7979 flow_dfs_compute_reverse_init (data)
7980 depth_first_search_ds data;
7982 /* Allocate stack for back-tracking up CFG. */
7984 (basic_block *) xmalloc ((n_basic_blocks - (INVALID_BLOCK + 1))
7985 * sizeof (basic_block));
7988 /* Allocate bitmap to track nodes that have been visited. */
7989 data->visited_blocks = sbitmap_alloc (n_basic_blocks - (INVALID_BLOCK + 1));
7991 /* None of the nodes in the CFG have been visited yet. */
7992 sbitmap_zero (data->visited_blocks);
7997 /* Add the specified basic block to the top of the dfs data
7998 structures. When the search continues, it will start at the
8002 flow_dfs_compute_reverse_add_bb (data, bb)
8003 depth_first_search_ds data;
8006 data->stack[data->sp++] = bb;
8010 /* Continue the depth-first search through the reverse graph starting
8011 with the block at the stack's top and ending when the stack is
8012 empty. Visited nodes are marked. Returns an unvisited basic
8013 block, or NULL if there is none available. */
8016 flow_dfs_compute_reverse_execute (data)
8017 depth_first_search_ds data;
8023 while (data->sp > 0)
8025 bb = data->stack[--data->sp];
8027 /* Mark that we have visited this node. */
8028 if (!TEST_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1)))
8030 SET_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1));
8032 /* Perform depth-first search on adjacent vertices. */
8033 for (e = bb->pred; e; e = e->pred_next)
8034 flow_dfs_compute_reverse_add_bb (data, e->src);
8038 /* Determine if there are unvisited basic blocks. */
8039 for (i = n_basic_blocks - (INVALID_BLOCK + 1); --i >= 0;)
8040 if (!TEST_BIT (data->visited_blocks, i))
8041 return BASIC_BLOCK (i + (INVALID_BLOCK + 1));
8045 /* Destroy the data structures needed for depth-first search on the
8049 flow_dfs_compute_reverse_finish (data)
8050 depth_first_search_ds data;
8053 sbitmap_free (data->visited_blocks);
8058 /* Find the root node of the loop pre-header extended basic block and
8059 the edges along the trace from the root node to the loop header. */
8062 flow_loop_pre_header_scan (loop)
8068 loop->num_pre_header_edges = 0;
8070 if (loop->num_entries != 1)
8073 ebb = loop->entry_edges[0]->src;
8075 if (ebb != ENTRY_BLOCK_PTR)
8079 /* Count number of edges along trace from loop header to
8080 root of pre-header extended basic block. Usually this is
8081 only one or two edges. */
8083 while (ebb->pred->src != ENTRY_BLOCK_PTR && ! ebb->pred->pred_next)
8085 ebb = ebb->pred->src;
8089 loop->pre_header_edges = (edge *) xmalloc (num * sizeof (edge *));
8090 loop->num_pre_header_edges = num;
8092 /* Store edges in order that they are followed. The source
8093 of the first edge is the root node of the pre-header extended
8094 basic block and the destination of the last last edge is
8096 for (e = loop->entry_edges[0]; num; e = e->src->pred)
8098 loop->pre_header_edges[--num] = e;
8104 /* Return the block for the pre-header of the loop with header
8105 HEADER where DOM specifies the dominator information. Return NULL if
8106 there is no pre-header. */
8109 flow_loop_pre_header_find (header, dom)
8113 basic_block pre_header;
8116 /* If block p is a predecessor of the header and is the only block
8117 that the header does not dominate, then it is the pre-header. */
8119 for (e = header->pred; e; e = e->pred_next)
8121 basic_block node = e->src;
8123 if (node != ENTRY_BLOCK_PTR
8124 && ! TEST_BIT (dom[node->index], header->index))
8126 if (pre_header == NULL)
8130 /* There are multiple edges into the header from outside
8131 the loop so there is no pre-header block. */
8140 /* Add LOOP to the loop hierarchy tree where PREVLOOP was the loop
8141 previously added. The insertion algorithm assumes that the loops
8142 are added in the order found by a depth first search of the CFG. */
8145 flow_loop_tree_node_add (prevloop, loop)
8146 struct loop *prevloop;
8150 if (flow_loop_nested_p (prevloop, loop))
8152 prevloop->inner = loop;
8153 loop->outer = prevloop;
8157 while (prevloop->outer)
8159 if (flow_loop_nested_p (prevloop->outer, loop))
8161 prevloop->next = loop;
8162 loop->outer = prevloop->outer;
8165 prevloop = prevloop->outer;
8168 prevloop->next = loop;
8172 /* Build the loop hierarchy tree for LOOPS. */
8175 flow_loops_tree_build (loops)
8176 struct loops *loops;
8181 num_loops = loops->num;
8185 /* Root the loop hierarchy tree with the first loop found.
8186 Since we used a depth first search this should be the
8188 loops->tree = &loops->array[0];
8189 loops->tree->outer = loops->tree->inner = loops->tree->next = NULL;
8191 /* Add the remaining loops to the tree. */
8192 for (i = 1; i < num_loops; i++)
8193 flow_loop_tree_node_add (&loops->array[i - 1], &loops->array[i]);
8196 /* Helper function to compute loop nesting depth and enclosed loop level
8197 for the natural loop specified by LOOP at the loop depth DEPTH.
8198 Returns the loop level. */
8201 flow_loop_level_compute (loop, depth)
8211 /* Traverse loop tree assigning depth and computing level as the
8212 maximum level of all the inner loops of this loop. The loop
8213 level is equivalent to the height of the loop in the loop tree
8214 and corresponds to the number of enclosed loop levels (including
8216 for (inner = loop->inner; inner; inner = inner->next)
8220 ilevel = flow_loop_level_compute (inner, depth + 1) + 1;
8225 loop->level = level;
8226 loop->depth = depth;
8230 /* Compute the loop nesting depth and enclosed loop level for the loop
8231 hierarchy tree specfied by LOOPS. Return the maximum enclosed loop
8235 flow_loops_level_compute (loops)
8236 struct loops *loops;
8242 /* Traverse all the outer level loops. */
8243 for (loop = loops->tree; loop; loop = loop->next)
8245 level = flow_loop_level_compute (loop, 1);
8253 /* Scan a single natural loop specified by LOOP collecting information
8254 about it specified by FLAGS. */
8257 flow_loop_scan (loops, loop, flags)
8258 struct loops *loops;
8262 /* Determine prerequisites. */
8263 if ((flags & LOOP_EXITS_DOMS) && ! loop->exit_edges)
8264 flags |= LOOP_EXIT_EDGES;
8266 if (flags & LOOP_ENTRY_EDGES)
8268 /* Find edges which enter the loop header.
8269 Note that the entry edges should only
8270 enter the header of a natural loop. */
8272 = flow_loop_entry_edges_find (loop->header,
8274 &loop->entry_edges);
8277 if (flags & LOOP_EXIT_EDGES)
8279 /* Find edges which exit the loop. */
8281 = flow_loop_exit_edges_find (loop->nodes,
8285 if (flags & LOOP_EXITS_DOMS)
8289 /* Determine which loop nodes dominate all the exits
8291 loop->exits_doms = sbitmap_alloc (n_basic_blocks);
8292 sbitmap_copy (loop->exits_doms, loop->nodes);
8293 for (j = 0; j < loop->num_exits; j++)
8294 sbitmap_a_and_b (loop->exits_doms, loop->exits_doms,
8295 loops->cfg.dom[loop->exit_edges[j]->src->index]);
8297 /* The header of a natural loop must dominate
8299 if (! TEST_BIT (loop->exits_doms, loop->header->index))
8303 if (flags & LOOP_PRE_HEADER)
8305 /* Look to see if the loop has a pre-header node. */
8307 = flow_loop_pre_header_find (loop->header, loops->cfg.dom);
8309 /* Find the blocks within the extended basic block of
8310 the loop pre-header. */
8311 flow_loop_pre_header_scan (loop);
8317 /* Find all the natural loops in the function and save in LOOPS structure
8318 and recalculate loop_depth information in basic block structures.
8319 FLAGS controls which loop information is collected.
8320 Return the number of natural loops found. */
8323 flow_loops_find (loops, flags)
8324 struct loops *loops;
8336 /* This function cannot be repeatedly called with different
8337 flags to build up the loop information. The loop tree
8338 must always be built if this function is called. */
8339 if (! (flags & LOOP_TREE))
8342 memset (loops, 0, sizeof (*loops));
8344 /* Taking care of this degenerate case makes the rest of
8345 this code simpler. */
8346 if (n_basic_blocks == 0)
8352 /* Compute the dominators. */
8353 dom = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
8354 calculate_dominance_info (NULL, dom, CDI_DOMINATORS);
8356 /* Count the number of loop edges (back edges). This should be the
8357 same as the number of natural loops. */
8360 for (b = 0; b < n_basic_blocks; b++)
8364 header = BASIC_BLOCK (b);
8365 header->loop_depth = 0;
8367 for (e = header->pred; e; e = e->pred_next)
8369 basic_block latch = e->src;
8371 /* Look for back edges where a predecessor is dominated
8372 by this block. A natural loop has a single entry
8373 node (header) that dominates all the nodes in the
8374 loop. It also has single back edge to the header
8375 from a latch node. Note that multiple natural loops
8376 may share the same header. */
8377 if (b != header->index)
8380 if (latch != ENTRY_BLOCK_PTR && TEST_BIT (dom[latch->index], b))
8387 /* Compute depth first search order of the CFG so that outer
8388 natural loops will be found before inner natural loops. */
8389 dfs_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
8390 rc_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
8391 flow_depth_first_order_compute (dfs_order, rc_order);
8393 /* Save CFG derived information to avoid recomputing it. */
8394 loops->cfg.dom = dom;
8395 loops->cfg.dfs_order = dfs_order;
8396 loops->cfg.rc_order = rc_order;
8398 /* Allocate loop structures. */
8400 = (struct loop *) xcalloc (num_loops, sizeof (struct loop));
8402 headers = sbitmap_alloc (n_basic_blocks);
8403 sbitmap_zero (headers);
8405 loops->shared_headers = sbitmap_alloc (n_basic_blocks);
8406 sbitmap_zero (loops->shared_headers);
8408 /* Find and record information about all the natural loops
8411 for (b = 0; b < n_basic_blocks; b++)
8415 /* Search the nodes of the CFG in reverse completion order
8416 so that we can find outer loops first. */
8417 header = BASIC_BLOCK (rc_order[b]);
8419 /* Look for all the possible latch blocks for this header. */
8420 for (e = header->pred; e; e = e->pred_next)
8422 basic_block latch = e->src;
8424 /* Look for back edges where a predecessor is dominated
8425 by this block. A natural loop has a single entry
8426 node (header) that dominates all the nodes in the
8427 loop. It also has single back edge to the header
8428 from a latch node. Note that multiple natural loops
8429 may share the same header. */
8430 if (latch != ENTRY_BLOCK_PTR
8431 && TEST_BIT (dom[latch->index], header->index))
8435 loop = loops->array + num_loops;
8437 loop->header = header;
8438 loop->latch = latch;
8439 loop->num = num_loops;
8446 for (i = 0; i < num_loops; i++)
8448 struct loop *loop = &loops->array[i];
8450 /* Keep track of blocks that are loop headers so
8451 that we can tell which loops should be merged. */
8452 if (TEST_BIT (headers, loop->header->index))
8453 SET_BIT (loops->shared_headers, loop->header->index);
8454 SET_BIT (headers, loop->header->index);
8456 /* Find nodes contained within the loop. */
8457 loop->nodes = sbitmap_alloc (n_basic_blocks);
8459 = flow_loop_nodes_find (loop->header, loop->latch, loop->nodes);
8461 /* Compute first and last blocks within the loop.
8462 These are often the same as the loop header and
8463 loop latch respectively, but this is not always
8466 = BASIC_BLOCK (sbitmap_first_set_bit (loop->nodes));
8468 = BASIC_BLOCK (sbitmap_last_set_bit (loop->nodes));
8470 flow_loop_scan (loops, loop, flags);
8473 /* Natural loops with shared headers may either be disjoint or
8474 nested. Disjoint loops with shared headers cannot be inner
8475 loops and should be merged. For now just mark loops that share
8477 for (i = 0; i < num_loops; i++)
8478 if (TEST_BIT (loops->shared_headers, loops->array[i].header->index))
8479 loops->array[i].shared = 1;
8481 sbitmap_free (headers);
8484 loops->num = num_loops;
8486 /* Build the loop hierarchy tree. */
8487 flow_loops_tree_build (loops);
8489 /* Assign the loop nesting depth and enclosed loop level for each
8491 loops->levels = flow_loops_level_compute (loops);
8497 /* Update the information regarding the loops in the CFG
8498 specified by LOOPS. */
8500 flow_loops_update (loops, flags)
8501 struct loops *loops;
8504 /* One day we may want to update the current loop data. For now
8505 throw away the old stuff and rebuild what we need. */
8507 flow_loops_free (loops);
8509 return flow_loops_find (loops, flags);
8513 /* Return non-zero if edge E enters header of LOOP from outside of LOOP. */
8516 flow_loop_outside_edge_p (loop, e)
8517 const struct loop *loop;
8520 if (e->dest != loop->header)
8522 return (e->src == ENTRY_BLOCK_PTR)
8523 || ! TEST_BIT (loop->nodes, e->src->index);
8526 /* Clear LOG_LINKS fields of insns in a chain.
8527 Also clear the global_live_at_{start,end} fields of the basic block
8531 clear_log_links (insns)
8537 for (i = insns; i; i = NEXT_INSN (i))
8541 for (b = 0; b < n_basic_blocks; b++)
8543 basic_block bb = BASIC_BLOCK (b);
8545 bb->global_live_at_start = NULL;
8546 bb->global_live_at_end = NULL;
8549 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
8550 EXIT_BLOCK_PTR->global_live_at_start = NULL;
8553 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
8554 correspond to the hard registers, if any, set in that map. This
8555 could be done far more efficiently by having all sorts of special-cases
8556 with moving single words, but probably isn't worth the trouble. */
8559 reg_set_to_hard_reg_set (to, from)
8565 EXECUTE_IF_SET_IN_BITMAP
8568 if (i >= FIRST_PSEUDO_REGISTER)
8570 SET_HARD_REG_BIT (*to, i);
8574 /* Called once at intialization time. */
8579 static int initialized;
8583 gcc_obstack_init (&flow_obstack);
8584 flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);
8589 obstack_free (&flow_obstack, flow_firstobj);
8590 flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);