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 /* ??? Set bb->frequency. */
1633 edge_in->flags &= ~EDGE_CRITICAL;
1635 edge_out->pred_next = old_succ->pred;
1636 edge_out->succ_next = NULL;
1638 edge_out->dest = old_succ;
1639 edge_out->flags = EDGE_FALLTHRU;
1640 edge_out->probability = REG_BR_PROB_BASE;
1641 edge_out->count = edge_in->count;
1643 old_succ->pred = edge_out;
1645 /* Tricky case -- if there existed a fallthru into the successor
1646 (and we're not it) we must add a new unconditional jump around
1647 the new block we're actually interested in.
1649 Further, if that edge is critical, this means a second new basic
1650 block must be created to hold it. In order to simplify correct
1651 insn placement, do this before we touch the existing basic block
1652 ordering for the block we were really wanting. */
1653 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1656 for (e = edge_out->pred_next; e; e = e->pred_next)
1657 if (e->flags & EDGE_FALLTHRU)
1662 basic_block jump_block;
1665 if ((e->flags & EDGE_CRITICAL) == 0
1666 && e->src != ENTRY_BLOCK_PTR)
1668 /* Non critical -- we can simply add a jump to the end
1669 of the existing predecessor. */
1670 jump_block = e->src;
1674 /* We need a new block to hold the jump. The simplest
1675 way to do the bulk of the work here is to recursively
1677 jump_block = split_edge (e);
1678 e = jump_block->succ;
1681 /* Now add the jump insn ... */
1682 pos = emit_jump_insn_after (gen_jump (old_succ->head),
1684 jump_block->end = pos;
1685 if (basic_block_for_insn)
1686 set_block_for_insn (pos, jump_block);
1687 emit_barrier_after (pos);
1689 /* ... let jump know that label is in use, ... */
1690 JUMP_LABEL (pos) = old_succ->head;
1691 ++LABEL_NUSES (old_succ->head);
1693 /* ... and clear fallthru on the outgoing edge. */
1694 e->flags &= ~EDGE_FALLTHRU;
1696 /* Continue splitting the interesting edge. */
1700 /* Place the new block just in front of the successor. */
1701 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
1702 if (old_succ == EXIT_BLOCK_PTR)
1703 j = n_basic_blocks - 1;
1705 j = old_succ->index;
1706 for (i = n_basic_blocks - 1; i > j; --i)
1708 basic_block tmp = BASIC_BLOCK (i - 1);
1709 BASIC_BLOCK (i) = tmp;
1712 BASIC_BLOCK (i) = bb;
1715 /* Create the basic block note.
1717 Where we place the note can have a noticable impact on the generated
1718 code. Consider this cfg:
1728 If we need to insert an insn on the edge from block 0 to block 1,
1729 we want to ensure the instructions we insert are outside of any
1730 loop notes that physically sit between block 0 and block 1. Otherwise
1731 we confuse the loop optimizer into thinking the loop is a phony. */
1732 if (old_succ != EXIT_BLOCK_PTR
1733 && PREV_INSN (old_succ->head)
1734 && GET_CODE (PREV_INSN (old_succ->head)) == NOTE
1735 && NOTE_LINE_NUMBER (PREV_INSN (old_succ->head)) == NOTE_INSN_LOOP_BEG)
1736 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
1737 PREV_INSN (old_succ->head));
1738 else if (old_succ != EXIT_BLOCK_PTR)
1739 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, old_succ->head);
1741 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
1742 NOTE_BASIC_BLOCK (bb_note) = bb;
1743 bb->head = bb->end = bb_note;
1745 /* Not quite simple -- for non-fallthru edges, we must adjust the
1746 predecessor's jump instruction to target our new block. */
1747 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1749 rtx tmp, insn = old_pred->end;
1750 rtx old_label = old_succ->head;
1751 rtx new_label = gen_label_rtx ();
1753 if (GET_CODE (insn) != JUMP_INSN)
1756 /* ??? Recognize a tablejump and adjust all matching cases. */
1757 if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1758 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1759 && GET_CODE (tmp) == JUMP_INSN
1760 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1761 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1766 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1767 vec = XVEC (PATTERN (tmp), 0);
1769 vec = XVEC (PATTERN (tmp), 1);
1771 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1772 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
1774 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (VOIDmode, new_label);
1775 --LABEL_NUSES (old_label);
1776 ++LABEL_NUSES (new_label);
1779 /* Handle casesi dispatch insns */
1780 if ((tmp = single_set (insn)) != NULL
1781 && SET_DEST (tmp) == pc_rtx
1782 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1783 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
1784 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
1786 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (VOIDmode,
1788 --LABEL_NUSES (old_label);
1789 ++LABEL_NUSES (new_label);
1794 /* This would have indicated an abnormal edge. */
1795 if (computed_jump_p (insn))
1798 /* A return instruction can't be redirected. */
1799 if (returnjump_p (insn))
1802 /* If the insn doesn't go where we think, we're confused. */
1803 if (JUMP_LABEL (insn) != old_label)
1806 redirect_jump (insn, new_label, 0);
1809 emit_label_before (new_label, bb_note);
1810 bb->head = new_label;
1816 /* Queue instructions for insertion on an edge between two basic blocks.
1817 The new instructions and basic blocks (if any) will not appear in the
1818 CFG until commit_edge_insertions is called. */
1821 insert_insn_on_edge (pattern, e)
1825 /* We cannot insert instructions on an abnormal critical edge.
1826 It will be easier to find the culprit if we die now. */
1827 if ((e->flags & (EDGE_ABNORMAL|EDGE_CRITICAL))
1828 == (EDGE_ABNORMAL|EDGE_CRITICAL))
1831 if (e->insns == NULL_RTX)
1834 push_to_sequence (e->insns);
1836 emit_insn (pattern);
1838 e->insns = get_insns ();
1842 /* Update the CFG for the instructions queued on edge E. */
1845 commit_one_edge_insertion (e)
1848 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
1851 /* Pull the insns off the edge now since the edge might go away. */
1853 e->insns = NULL_RTX;
1855 /* Figure out where to put these things. If the destination has
1856 one predecessor, insert there. Except for the exit block. */
1857 if (e->dest->pred->pred_next == NULL
1858 && e->dest != EXIT_BLOCK_PTR)
1862 /* Get the location correct wrt a code label, and "nice" wrt
1863 a basic block note, and before everything else. */
1865 if (GET_CODE (tmp) == CODE_LABEL)
1866 tmp = NEXT_INSN (tmp);
1867 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
1868 tmp = NEXT_INSN (tmp);
1869 if (tmp == bb->head)
1872 after = PREV_INSN (tmp);
1875 /* If the source has one successor and the edge is not abnormal,
1876 insert there. Except for the entry block. */
1877 else if ((e->flags & EDGE_ABNORMAL) == 0
1878 && e->src->succ->succ_next == NULL
1879 && e->src != ENTRY_BLOCK_PTR)
1882 /* It is possible to have a non-simple jump here. Consider a target
1883 where some forms of unconditional jumps clobber a register. This
1884 happens on the fr30 for example.
1886 We know this block has a single successor, so we can just emit
1887 the queued insns before the jump. */
1888 if (GET_CODE (bb->end) == JUMP_INSN)
1894 /* We'd better be fallthru, or we've lost track of what's what. */
1895 if ((e->flags & EDGE_FALLTHRU) == 0)
1902 /* Otherwise we must split the edge. */
1905 bb = split_edge (e);
1909 /* Now that we've found the spot, do the insertion. */
1911 /* Set the new block number for these insns, if structure is allocated. */
1912 if (basic_block_for_insn)
1915 for (i = insns; i != NULL_RTX; i = NEXT_INSN (i))
1916 set_block_for_insn (i, bb);
1921 emit_insns_before (insns, before);
1922 if (before == bb->head)
1925 last = prev_nonnote_insn (before);
1929 last = emit_insns_after (insns, after);
1930 if (after == bb->end)
1934 if (returnjump_p (last))
1936 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1937 This is not currently a problem because this only happens
1938 for the (single) epilogue, which already has a fallthru edge
1942 if (e->dest != EXIT_BLOCK_PTR
1943 || e->succ_next != NULL
1944 || (e->flags & EDGE_FALLTHRU) == 0)
1946 e->flags &= ~EDGE_FALLTHRU;
1948 emit_barrier_after (last);
1952 flow_delete_insn (before);
1954 else if (GET_CODE (last) == JUMP_INSN)
1956 find_sub_basic_blocks (bb);
1959 /* Update the CFG for all queued instructions. */
1962 commit_edge_insertions ()
1967 #ifdef ENABLE_CHECKING
1968 verify_flow_info ();
1972 bb = ENTRY_BLOCK_PTR;
1977 for (e = bb->succ; e; e = next)
1979 next = e->succ_next;
1981 commit_one_edge_insertion (e);
1984 if (++i >= n_basic_blocks)
1986 bb = BASIC_BLOCK (i);
1990 /* Add fake edges to the function exit for any non constant calls in
1991 the bitmap of blocks specified by BLOCKS or to the whole CFG if
1992 BLOCKS is zero. Return the nuber of blocks that were split. */
1995 flow_call_edges_add (blocks)
1999 int blocks_split = 0;
2003 /* Map bb indicies into basic block pointers since split_block
2004 will renumber the basic blocks. */
2006 bbs = xmalloc (n_basic_blocks * sizeof (*bbs));
2010 for (i = 0; i < n_basic_blocks; i++)
2011 bbs[bb_num++] = BASIC_BLOCK (i);
2015 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
2017 bbs[bb_num++] = BASIC_BLOCK (i);
2022 /* Now add fake edges to the function exit for any non constant
2023 calls since there is no way that we can determine if they will
2026 for (i = 0; i < bb_num; i++)
2028 basic_block bb = bbs[i];
2032 for (insn = bb->end; ; insn = prev_insn)
2034 prev_insn = PREV_INSN (insn);
2035 if (GET_CODE (insn) == CALL_INSN && ! CONST_CALL_P (insn))
2039 /* Note that the following may create a new basic block
2040 and renumber the existing basic blocks. */
2041 e = split_block (bb, insn);
2045 make_edge (NULL, bb, EXIT_BLOCK_PTR, EDGE_FAKE);
2047 if (insn == bb->head)
2053 verify_flow_info ();
2056 return blocks_split;
2059 /* Find unreachable blocks. An unreachable block will have NULL in
2060 block->aux, a non-NULL value indicates the block is reachable. */
2063 find_unreachable_blocks ()
2067 basic_block *tos, *worklist;
2070 tos = worklist = (basic_block *) xmalloc (sizeof (basic_block) * n);
2072 /* Use basic_block->aux as a marker. Clear them all. */
2074 for (i = 0; i < n; ++i)
2075 BASIC_BLOCK (i)->aux = NULL;
2077 /* Add our starting points to the worklist. Almost always there will
2078 be only one. It isn't inconcievable that we might one day directly
2079 support Fortran alternate entry points. */
2081 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
2085 /* Mark the block with a handy non-null value. */
2089 /* Iterate: find everything reachable from what we've already seen. */
2091 while (tos != worklist)
2093 basic_block b = *--tos;
2095 for (e = b->succ; e; e = e->succ_next)
2106 /* Delete all unreachable basic blocks. */
2108 delete_unreachable_blocks ()
2112 find_unreachable_blocks ();
2114 /* Delete all unreachable basic blocks. Count down so that we
2115 don't interfere with the block renumbering that happens in
2116 flow_delete_block. */
2118 for (i = n_basic_blocks - 1; i >= 0; --i)
2120 basic_block b = BASIC_BLOCK (i);
2123 /* This block was found. Tidy up the mark. */
2126 flow_delete_block (b);
2129 tidy_fallthru_edges ();
2132 /* Return true if NOTE is not one of the ones that must be kept paired,
2133 so that we may simply delete them. */
2136 can_delete_note_p (note)
2139 return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED
2140 || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK);
2143 /* Unlink a chain of insns between START and FINISH, leaving notes
2144 that must be paired. */
2147 flow_delete_insn_chain (start, finish)
2150 /* Unchain the insns one by one. It would be quicker to delete all
2151 of these with a single unchaining, rather than one at a time, but
2152 we need to keep the NOTE's. */
2158 next = NEXT_INSN (start);
2159 if (GET_CODE (start) == NOTE && !can_delete_note_p (start))
2161 else if (GET_CODE (start) == CODE_LABEL
2162 && ! can_delete_label_p (start))
2164 const char *name = LABEL_NAME (start);
2165 PUT_CODE (start, NOTE);
2166 NOTE_LINE_NUMBER (start) = NOTE_INSN_DELETED_LABEL;
2167 NOTE_SOURCE_FILE (start) = name;
2170 next = flow_delete_insn (start);
2172 if (start == finish)
2178 /* Delete the insns in a (non-live) block. We physically delete every
2179 non-deleted-note insn, and update the flow graph appropriately.
2181 Return nonzero if we deleted an exception handler. */
2183 /* ??? Preserving all such notes strikes me as wrong. It would be nice
2184 to post-process the stream to remove empty blocks, loops, ranges, etc. */
2187 flow_delete_block (b)
2190 int deleted_handler = 0;
2193 /* If the head of this block is a CODE_LABEL, then it might be the
2194 label for an exception handler which can't be reached.
2196 We need to remove the label from the exception_handler_label list
2197 and remove the associated NOTE_INSN_EH_REGION_BEG and
2198 NOTE_INSN_EH_REGION_END notes. */
2202 never_reached_warning (insn);
2204 if (GET_CODE (insn) == CODE_LABEL)
2205 maybe_remove_eh_handler (insn);
2207 /* Include any jump table following the basic block. */
2209 if (GET_CODE (end) == JUMP_INSN
2210 && (tmp = JUMP_LABEL (end)) != NULL_RTX
2211 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
2212 && GET_CODE (tmp) == JUMP_INSN
2213 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
2214 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
2217 /* Include any barrier that may follow the basic block. */
2218 tmp = next_nonnote_insn (end);
2219 if (tmp && GET_CODE (tmp) == BARRIER)
2222 /* Selectively delete the entire chain. */
2223 flow_delete_insn_chain (insn, end);
2225 /* Remove the edges into and out of this block. Note that there may
2226 indeed be edges in, if we are removing an unreachable loop. */
2230 for (e = b->pred; e; e = next)
2232 for (q = &e->src->succ; *q != e; q = &(*q)->succ_next)
2235 next = e->pred_next;
2239 for (e = b->succ; e; e = next)
2241 for (q = &e->dest->pred; *q != e; q = &(*q)->pred_next)
2244 next = e->succ_next;
2253 /* Remove the basic block from the array, and compact behind it. */
2256 return deleted_handler;
2259 /* Remove block B from the basic block array and compact behind it. */
2265 int i, n = n_basic_blocks;
2267 for (i = b->index; i + 1 < n; ++i)
2269 basic_block x = BASIC_BLOCK (i + 1);
2270 BASIC_BLOCK (i) = x;
2274 basic_block_info->num_elements--;
2278 /* Delete INSN by patching it out. Return the next insn. */
2281 flow_delete_insn (insn)
2284 rtx prev = PREV_INSN (insn);
2285 rtx next = NEXT_INSN (insn);
2288 PREV_INSN (insn) = NULL_RTX;
2289 NEXT_INSN (insn) = NULL_RTX;
2290 INSN_DELETED_P (insn) = 1;
2293 NEXT_INSN (prev) = next;
2295 PREV_INSN (next) = prev;
2297 set_last_insn (prev);
2299 if (GET_CODE (insn) == CODE_LABEL)
2300 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2302 /* If deleting a jump, decrement the use count of the label. Deleting
2303 the label itself should happen in the normal course of block merging. */
2304 if (GET_CODE (insn) == JUMP_INSN
2305 && JUMP_LABEL (insn)
2306 && GET_CODE (JUMP_LABEL (insn)) == CODE_LABEL)
2307 LABEL_NUSES (JUMP_LABEL (insn))--;
2309 /* Also if deleting an insn that references a label. */
2310 else if ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX
2311 && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
2312 LABEL_NUSES (XEXP (note, 0))--;
2317 /* True if a given label can be deleted. */
2320 can_delete_label_p (label)
2325 if (LABEL_PRESERVE_P (label))
2328 for (x = forced_labels; x; x = XEXP (x, 1))
2329 if (label == XEXP (x, 0))
2331 for (x = label_value_list; x; x = XEXP (x, 1))
2332 if (label == XEXP (x, 0))
2334 for (x = exception_handler_labels; x; x = XEXP (x, 1))
2335 if (label == XEXP (x, 0))
2338 /* User declared labels must be preserved. */
2339 if (LABEL_NAME (label) != 0)
2346 tail_recursion_label_p (label)
2351 for (x = tail_recursion_label_list; x; x = XEXP (x, 1))
2352 if (label == XEXP (x, 0))
2358 /* Blocks A and B are to be merged into a single block A. The insns
2359 are already contiguous, hence `nomove'. */
2362 merge_blocks_nomove (a, b)
2366 rtx b_head, b_end, a_end;
2367 rtx del_first = NULL_RTX, del_last = NULL_RTX;
2370 /* If there was a CODE_LABEL beginning B, delete it. */
2373 if (GET_CODE (b_head) == CODE_LABEL)
2375 /* Detect basic blocks with nothing but a label. This can happen
2376 in particular at the end of a function. */
2377 if (b_head == b_end)
2379 del_first = del_last = b_head;
2380 b_head = NEXT_INSN (b_head);
2383 /* Delete the basic block note. */
2384 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
2386 if (b_head == b_end)
2391 b_head = NEXT_INSN (b_head);
2394 /* If there was a jump out of A, delete it. */
2396 if (GET_CODE (a_end) == JUMP_INSN)
2400 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
2401 if (GET_CODE (prev) != NOTE
2402 || NOTE_LINE_NUMBER (prev) == NOTE_INSN_BASIC_BLOCK
2409 /* If this was a conditional jump, we need to also delete
2410 the insn that set cc0. */
2411 if (prev && sets_cc0_p (prev))
2414 prev = prev_nonnote_insn (prev);
2423 else if (GET_CODE (NEXT_INSN (a_end)) == BARRIER)
2424 del_first = NEXT_INSN (a_end);
2426 /* Delete everything marked above as well as crap that might be
2427 hanging out between the two blocks. */
2428 flow_delete_insn_chain (del_first, del_last);
2430 /* Normally there should only be one successor of A and that is B, but
2431 partway though the merge of blocks for conditional_execution we'll
2432 be merging a TEST block with THEN and ELSE successors. Free the
2433 whole lot of them and hope the caller knows what they're doing. */
2435 remove_edge (a->succ);
2437 /* Adjust the edges out of B for the new owner. */
2438 for (e = b->succ; e; e = e->succ_next)
2442 /* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */
2443 b->pred = b->succ = NULL;
2445 /* Reassociate the insns of B with A. */
2448 if (basic_block_for_insn)
2450 BLOCK_FOR_INSN (b_head) = a;
2451 while (b_head != b_end)
2453 b_head = NEXT_INSN (b_head);
2454 BLOCK_FOR_INSN (b_head) = a;
2464 /* Blocks A and B are to be merged into a single block. A has no incoming
2465 fallthru edge, so it can be moved before B without adding or modifying
2466 any jumps (aside from the jump from A to B). */
2469 merge_blocks_move_predecessor_nojumps (a, b)
2472 rtx start, end, barrier;
2478 barrier = next_nonnote_insn (end);
2479 if (GET_CODE (barrier) != BARRIER)
2481 flow_delete_insn (barrier);
2483 /* Move block and loop notes out of the chain so that we do not
2484 disturb their order.
2486 ??? A better solution would be to squeeze out all the non-nested notes
2487 and adjust the block trees appropriately. Even better would be to have
2488 a tighter connection between block trees and rtl so that this is not
2490 start = squeeze_notes (start, end);
2492 /* Scramble the insn chain. */
2493 if (end != PREV_INSN (b->head))
2494 reorder_insns (start, end, PREV_INSN (b->head));
2498 fprintf (rtl_dump_file, "Moved block %d before %d and merged.\n",
2499 a->index, b->index);
2502 /* Swap the records for the two blocks around. Although we are deleting B,
2503 A is now where B was and we want to compact the BB array from where
2505 BASIC_BLOCK (a->index) = b;
2506 BASIC_BLOCK (b->index) = a;
2508 a->index = b->index;
2511 /* Now blocks A and B are contiguous. Merge them. */
2512 merge_blocks_nomove (a, b);
2517 /* Blocks A and B are to be merged into a single block. B has no outgoing
2518 fallthru edge, so it can be moved after A without adding or modifying
2519 any jumps (aside from the jump from A to B). */
2522 merge_blocks_move_successor_nojumps (a, b)
2525 rtx start, end, barrier;
2529 barrier = NEXT_INSN (end);
2531 /* Recognize a jump table following block B. */
2532 if (GET_CODE (barrier) == CODE_LABEL
2533 && NEXT_INSN (barrier)
2534 && GET_CODE (NEXT_INSN (barrier)) == JUMP_INSN
2535 && (GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_VEC
2536 || GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_DIFF_VEC))
2538 end = NEXT_INSN (barrier);
2539 barrier = NEXT_INSN (end);
2542 /* There had better have been a barrier there. Delete it. */
2543 if (GET_CODE (barrier) != BARRIER)
2545 flow_delete_insn (barrier);
2547 /* Move block and loop notes out of the chain so that we do not
2548 disturb their order.
2550 ??? A better solution would be to squeeze out all the non-nested notes
2551 and adjust the block trees appropriately. Even better would be to have
2552 a tighter connection between block trees and rtl so that this is not
2554 start = squeeze_notes (start, end);
2556 /* Scramble the insn chain. */
2557 reorder_insns (start, end, a->end);
2559 /* Now blocks A and B are contiguous. Merge them. */
2560 merge_blocks_nomove (a, b);
2564 fprintf (rtl_dump_file, "Moved block %d after %d and merged.\n",
2565 b->index, a->index);
2571 /* Attempt to merge basic blocks that are potentially non-adjacent.
2572 Return true iff the attempt succeeded. */
2575 merge_blocks (e, b, c)
2579 /* If C has a tail recursion label, do not merge. There is no
2580 edge recorded from the call_placeholder back to this label, as
2581 that would make optimize_sibling_and_tail_recursive_calls more
2582 complex for no gain. */
2583 if (GET_CODE (c->head) == CODE_LABEL
2584 && tail_recursion_label_p (c->head))
2587 /* If B has a fallthru edge to C, no need to move anything. */
2588 if (e->flags & EDGE_FALLTHRU)
2590 merge_blocks_nomove (b, c);
2594 fprintf (rtl_dump_file, "Merged %d and %d without moving.\n",
2595 b->index, c->index);
2603 int c_has_outgoing_fallthru;
2604 int b_has_incoming_fallthru;
2606 /* We must make sure to not munge nesting of exception regions,
2607 lexical blocks, and loop notes.
2609 The first is taken care of by requiring that the active eh
2610 region at the end of one block always matches the active eh
2611 region at the beginning of the next block.
2613 The later two are taken care of by squeezing out all the notes. */
2615 /* ??? A throw/catch edge (or any abnormal edge) should be rarely
2616 executed and we may want to treat blocks which have two out
2617 edges, one normal, one abnormal as only having one edge for
2618 block merging purposes. */
2620 for (tmp_edge = c->succ; tmp_edge; tmp_edge = tmp_edge->succ_next)
2621 if (tmp_edge->flags & EDGE_FALLTHRU)
2623 c_has_outgoing_fallthru = (tmp_edge != NULL);
2625 for (tmp_edge = b->pred; tmp_edge; tmp_edge = tmp_edge->pred_next)
2626 if (tmp_edge->flags & EDGE_FALLTHRU)
2628 b_has_incoming_fallthru = (tmp_edge != NULL);
2630 /* If B does not have an incoming fallthru, then it can be moved
2631 immediately before C without introducing or modifying jumps.
2632 C cannot be the first block, so we do not have to worry about
2633 accessing a non-existent block. */
2634 if (! b_has_incoming_fallthru)
2635 return merge_blocks_move_predecessor_nojumps (b, c);
2637 /* Otherwise, we're going to try to move C after B. If C does
2638 not have an outgoing fallthru, then it can be moved
2639 immediately after B without introducing or modifying jumps. */
2640 if (! c_has_outgoing_fallthru)
2641 return merge_blocks_move_successor_nojumps (b, c);
2643 /* Otherwise, we'll need to insert an extra jump, and possibly
2644 a new block to contain it. */
2645 /* ??? Not implemented yet. */
2651 /* Top level driver for merge_blocks. */
2658 /* Attempt to merge blocks as made possible by edge removal. If a block
2659 has only one successor, and the successor has only one predecessor,
2660 they may be combined. */
2662 for (i = 0; i < n_basic_blocks;)
2664 basic_block c, b = BASIC_BLOCK (i);
2667 /* A loop because chains of blocks might be combineable. */
2668 while ((s = b->succ) != NULL
2669 && s->succ_next == NULL
2670 && (s->flags & EDGE_EH) == 0
2671 && (c = s->dest) != EXIT_BLOCK_PTR
2672 && c->pred->pred_next == NULL
2673 /* If the jump insn has side effects, we can't kill the edge. */
2674 && (GET_CODE (b->end) != JUMP_INSN
2675 || onlyjump_p (b->end))
2676 && merge_blocks (s, b, c))
2679 /* Don't get confused by the index shift caused by deleting blocks. */
2684 /* The given edge should potentially be a fallthru edge. If that is in
2685 fact true, delete the jump and barriers that are in the way. */
2688 tidy_fallthru_edge (e, b, c)
2694 /* ??? In a late-running flow pass, other folks may have deleted basic
2695 blocks by nopping out blocks, leaving multiple BARRIERs between here
2696 and the target label. They ought to be chastized and fixed.
2698 We can also wind up with a sequence of undeletable labels between
2699 one block and the next.
2701 So search through a sequence of barriers, labels, and notes for
2702 the head of block C and assert that we really do fall through. */
2704 if (next_real_insn (b->end) != next_real_insn (PREV_INSN (c->head)))
2707 /* Remove what will soon cease being the jump insn from the source block.
2708 If block B consisted only of this single jump, turn it into a deleted
2711 if (GET_CODE (q) == JUMP_INSN
2713 && (any_uncondjump_p (q)
2714 || (b->succ == e && e->succ_next == NULL)))
2717 /* If this was a conditional jump, we need to also delete
2718 the insn that set cc0. */
2719 if (any_condjump_p (q) && sets_cc0_p (PREV_INSN (q)))
2726 NOTE_LINE_NUMBER (q) = NOTE_INSN_DELETED;
2727 NOTE_SOURCE_FILE (q) = 0;
2733 /* We don't want a block to end on a line-number note since that has
2734 the potential of changing the code between -g and not -g. */
2735 while (GET_CODE (q) == NOTE && NOTE_LINE_NUMBER (q) >= 0)
2742 /* Selectively unlink the sequence. */
2743 if (q != PREV_INSN (c->head))
2744 flow_delete_insn_chain (NEXT_INSN (q), PREV_INSN (c->head));
2746 e->flags |= EDGE_FALLTHRU;
2749 /* Fix up edges that now fall through, or rather should now fall through
2750 but previously required a jump around now deleted blocks. Simplify
2751 the search by only examining blocks numerically adjacent, since this
2752 is how find_basic_blocks created them. */
2755 tidy_fallthru_edges ()
2759 for (i = 1; i < n_basic_blocks; ++i)
2761 basic_block b = BASIC_BLOCK (i - 1);
2762 basic_block c = BASIC_BLOCK (i);
2765 /* We care about simple conditional or unconditional jumps with
2768 If we had a conditional branch to the next instruction when
2769 find_basic_blocks was called, then there will only be one
2770 out edge for the block which ended with the conditional
2771 branch (since we do not create duplicate edges).
2773 Furthermore, the edge will be marked as a fallthru because we
2774 merge the flags for the duplicate edges. So we do not want to
2775 check that the edge is not a FALLTHRU edge. */
2776 if ((s = b->succ) != NULL
2777 && ! (s->flags & EDGE_COMPLEX)
2778 && s->succ_next == NULL
2780 /* If the jump insn has side effects, we can't tidy the edge. */
2781 && (GET_CODE (b->end) != JUMP_INSN
2782 || onlyjump_p (b->end)))
2783 tidy_fallthru_edge (s, b, c);
2787 /* Perform data flow analysis.
2788 F is the first insn of the function; FLAGS is a set of PROP_* flags
2789 to be used in accumulating flow info. */
2792 life_analysis (f, file, flags)
2797 #ifdef ELIMINABLE_REGS
2799 static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
2802 /* Record which registers will be eliminated. We use this in
2805 CLEAR_HARD_REG_SET (elim_reg_set);
2807 #ifdef ELIMINABLE_REGS
2808 for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
2809 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
2811 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
2815 flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC);
2817 /* The post-reload life analysis have (on a global basis) the same
2818 registers live as was computed by reload itself. elimination
2819 Otherwise offsets and such may be incorrect.
2821 Reload will make some registers as live even though they do not
2824 We don't want to create new auto-incs after reload, since they
2825 are unlikely to be useful and can cause problems with shared
2827 if (reload_completed)
2828 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
2830 /* We want alias analysis information for local dead store elimination. */
2831 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
2832 init_alias_analysis ();
2834 /* Always remove no-op moves. Do this before other processing so
2835 that we don't have to keep re-scanning them. */
2836 delete_noop_moves (f);
2838 /* Some targets can emit simpler epilogues if they know that sp was
2839 not ever modified during the function. After reload, of course,
2840 we've already emitted the epilogue so there's no sense searching. */
2841 if (! reload_completed)
2842 notice_stack_pointer_modification (f);
2844 /* Allocate and zero out data structures that will record the
2845 data from lifetime analysis. */
2846 allocate_reg_life_data ();
2847 allocate_bb_life_data ();
2849 /* Find the set of registers live on function exit. */
2850 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
2852 /* "Update" life info from zero. It'd be nice to begin the
2853 relaxation with just the exit and noreturn blocks, but that set
2854 is not immediately handy. */
2856 if (flags & PROP_REG_INFO)
2857 memset (regs_ever_live, 0, sizeof (regs_ever_live));
2858 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
2861 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
2862 end_alias_analysis ();
2865 dump_flow_info (file);
2867 free_basic_block_vars (1);
2869 #ifdef ENABLE_CHECKING
2873 /* Search for any REG_LABEL notes which reference deleted labels. */
2874 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
2876 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
2878 if (inote && GET_CODE (inote) == NOTE_INSN_DELETED_LABEL)
2885 /* A subroutine of verify_wide_reg, called through for_each_rtx.
2886 Search for REGNO. If found, abort if it is not wider than word_mode. */
2889 verify_wide_reg_1 (px, pregno)
2894 unsigned int regno = *(int *) pregno;
2896 if (GET_CODE (x) == REG && REGNO (x) == regno)
2898 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
2905 /* A subroutine of verify_local_live_at_start. Search through insns
2906 between HEAD and END looking for register REGNO. */
2909 verify_wide_reg (regno, head, end)
2916 && for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no))
2920 head = NEXT_INSN (head);
2923 /* We didn't find the register at all. Something's way screwy. */
2925 fprintf (rtl_dump_file, "Aborting in verify_wide_reg; reg %d\n", regno);
2926 print_rtl_and_abort ();
2929 /* A subroutine of update_life_info. Verify that there are no untoward
2930 changes in live_at_start during a local update. */
2933 verify_local_live_at_start (new_live_at_start, bb)
2934 regset new_live_at_start;
2937 if (reload_completed)
2939 /* After reload, there are no pseudos, nor subregs of multi-word
2940 registers. The regsets should exactly match. */
2941 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
2945 fprintf (rtl_dump_file,
2946 "live_at_start mismatch in bb %d, aborting\n",
2948 debug_bitmap_file (rtl_dump_file, bb->global_live_at_start);
2949 debug_bitmap_file (rtl_dump_file, new_live_at_start);
2951 print_rtl_and_abort ();
2958 /* Find the set of changed registers. */
2959 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
2961 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
2963 /* No registers should die. */
2964 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
2967 fprintf (rtl_dump_file,
2968 "Register %d died unexpectedly in block %d\n", i,
2970 print_rtl_and_abort ();
2973 /* Verify that the now-live register is wider than word_mode. */
2974 verify_wide_reg (i, bb->head, bb->end);
2979 /* Updates life information starting with the basic blocks set in BLOCKS.
2980 If BLOCKS is null, consider it to be the universal set.
2982 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
2983 we are only expecting local modifications to basic blocks. If we find
2984 extra registers live at the beginning of a block, then we either killed
2985 useful data, or we have a broken split that wants data not provided.
2986 If we find registers removed from live_at_start, that means we have
2987 a broken peephole that is killing a register it shouldn't.
2989 ??? This is not true in one situation -- when a pre-reload splitter
2990 generates subregs of a multi-word pseudo, current life analysis will
2991 lose the kill. So we _can_ have a pseudo go live. How irritating.
2993 Including PROP_REG_INFO does not properly refresh regs_ever_live
2994 unless the caller resets it to zero. */
2997 update_life_info (blocks, extent, prop_flags)
2999 enum update_life_extent extent;
3003 regset_head tmp_head;
3006 tmp = INITIALIZE_REG_SET (tmp_head);
3008 /* For a global update, we go through the relaxation process again. */
3009 if (extent != UPDATE_LIFE_LOCAL)
3011 calculate_global_regs_live (blocks, blocks,
3012 prop_flags & PROP_SCAN_DEAD_CODE);
3014 /* If asked, remove notes from the blocks we'll update. */
3015 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
3016 count_or_remove_death_notes (blocks, 1);
3021 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
3023 basic_block bb = BASIC_BLOCK (i);
3025 COPY_REG_SET (tmp, bb->global_live_at_end);
3026 propagate_block (bb, tmp, NULL, NULL, prop_flags);
3028 if (extent == UPDATE_LIFE_LOCAL)
3029 verify_local_live_at_start (tmp, bb);
3034 for (i = n_basic_blocks - 1; i >= 0; --i)
3036 basic_block bb = BASIC_BLOCK (i);
3038 COPY_REG_SET (tmp, bb->global_live_at_end);
3039 propagate_block (bb, tmp, NULL, NULL, prop_flags);
3041 if (extent == UPDATE_LIFE_LOCAL)
3042 verify_local_live_at_start (tmp, bb);
3048 if (prop_flags & PROP_REG_INFO)
3050 /* The only pseudos that are live at the beginning of the function
3051 are those that were not set anywhere in the function. local-alloc
3052 doesn't know how to handle these correctly, so mark them as not
3053 local to any one basic block. */
3054 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
3055 FIRST_PSEUDO_REGISTER, i,
3056 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
3058 /* We have a problem with any pseudoreg that lives across the setjmp.
3059 ANSI says that if a user variable does not change in value between
3060 the setjmp and the longjmp, then the longjmp preserves it. This
3061 includes longjmp from a place where the pseudo appears dead.
3062 (In principle, the value still exists if it is in scope.)
3063 If the pseudo goes in a hard reg, some other value may occupy
3064 that hard reg where this pseudo is dead, thus clobbering the pseudo.
3065 Conclusion: such a pseudo must not go in a hard reg. */
3066 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
3067 FIRST_PSEUDO_REGISTER, i,
3069 if (regno_reg_rtx[i] != 0)
3071 REG_LIVE_LENGTH (i) = -1;
3072 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
3078 /* Free the variables allocated by find_basic_blocks.
3080 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
3083 free_basic_block_vars (keep_head_end_p)
3084 int keep_head_end_p;
3086 if (basic_block_for_insn)
3088 VARRAY_FREE (basic_block_for_insn);
3089 basic_block_for_insn = NULL;
3092 if (! keep_head_end_p)
3094 if (basic_block_info)
3097 VARRAY_FREE (basic_block_info);
3101 ENTRY_BLOCK_PTR->aux = NULL;
3102 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
3103 EXIT_BLOCK_PTR->aux = NULL;
3104 EXIT_BLOCK_PTR->global_live_at_start = NULL;
3108 /* Return nonzero if an insn consists only of SETs, each of which only sets a
3115 rtx pat = PATTERN (insn);
3117 /* Insns carrying these notes are useful later on. */
3118 if (find_reg_note (insn, REG_EQUAL, NULL_RTX))
3121 if (GET_CODE (pat) == SET && set_noop_p (pat))
3124 if (GET_CODE (pat) == PARALLEL)
3127 /* If nothing but SETs of registers to themselves,
3128 this insn can also be deleted. */
3129 for (i = 0; i < XVECLEN (pat, 0); i++)
3131 rtx tem = XVECEXP (pat, 0, i);
3133 if (GET_CODE (tem) == USE
3134 || GET_CODE (tem) == CLOBBER)
3137 if (GET_CODE (tem) != SET || ! set_noop_p (tem))
3146 /* Delete any insns that copy a register to itself. */
3149 delete_noop_moves (f)
3153 for (insn = f; insn; insn = NEXT_INSN (insn))
3155 if (GET_CODE (insn) == INSN && noop_move_p (insn))
3157 PUT_CODE (insn, NOTE);
3158 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
3159 NOTE_SOURCE_FILE (insn) = 0;
3164 /* Determine if the stack pointer is constant over the life of the function.
3165 Only useful before prologues have been emitted. */
3168 notice_stack_pointer_modification_1 (x, pat, data)
3170 rtx pat ATTRIBUTE_UNUSED;
3171 void *data ATTRIBUTE_UNUSED;
3173 if (x == stack_pointer_rtx
3174 /* The stack pointer is only modified indirectly as the result
3175 of a push until later in flow. See the comments in rtl.texi
3176 regarding Embedded Side-Effects on Addresses. */
3177 || (GET_CODE (x) == MEM
3178 && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
3179 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
3180 current_function_sp_is_unchanging = 0;
3184 notice_stack_pointer_modification (f)
3189 /* Assume that the stack pointer is unchanging if alloca hasn't
3191 current_function_sp_is_unchanging = !current_function_calls_alloca;
3192 if (! current_function_sp_is_unchanging)
3195 for (insn = f; insn; insn = NEXT_INSN (insn))
3199 /* Check if insn modifies the stack pointer. */
3200 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
3202 if (! current_function_sp_is_unchanging)
3208 /* Mark a register in SET. Hard registers in large modes get all
3209 of their component registers set as well. */
3212 mark_reg (reg, xset)
3216 regset set = (regset) xset;
3217 int regno = REGNO (reg);
3219 if (GET_MODE (reg) == BLKmode)
3222 SET_REGNO_REG_SET (set, regno);
3223 if (regno < FIRST_PSEUDO_REGISTER)
3225 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
3227 SET_REGNO_REG_SET (set, regno + n);
3231 /* Mark those regs which are needed at the end of the function as live
3232 at the end of the last basic block. */
3235 mark_regs_live_at_end (set)
3240 /* If exiting needs the right stack value, consider the stack pointer
3241 live at the end of the function. */
3242 if ((HAVE_epilogue && reload_completed)
3243 || ! EXIT_IGNORE_STACK
3244 || (! FRAME_POINTER_REQUIRED
3245 && ! current_function_calls_alloca
3246 && flag_omit_frame_pointer)
3247 || current_function_sp_is_unchanging)
3249 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
3252 /* Mark the frame pointer if needed at the end of the function. If
3253 we end up eliminating it, it will be removed from the live list
3254 of each basic block by reload. */
3256 if (! reload_completed || frame_pointer_needed)
3258 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
3259 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3260 /* If they are different, also mark the hard frame pointer as live. */
3261 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
3262 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
3266 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
3267 /* Many architectures have a GP register even without flag_pic.
3268 Assume the pic register is not in use, or will be handled by
3269 other means, if it is not fixed. */
3270 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
3271 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
3272 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
3275 /* Mark all global registers, and all registers used by the epilogue
3276 as being live at the end of the function since they may be
3277 referenced by our caller. */
3278 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3279 if (global_regs[i] || EPILOGUE_USES (i))
3280 SET_REGNO_REG_SET (set, i);
3282 if (HAVE_epilogue && reload_completed)
3284 /* Mark all call-saved registers that we actually used. */
3285 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3286 if (regs_ever_live[i] && ! call_used_regs[i] && ! LOCAL_REGNO (i))
3287 SET_REGNO_REG_SET (set, i);
3290 #ifdef EH_RETURN_DATA_REGNO
3291 /* Mark the registers that will contain data for the handler. */
3292 if (reload_completed && current_function_calls_eh_return)
3295 unsigned regno = EH_RETURN_DATA_REGNO(i);
3296 if (regno == INVALID_REGNUM)
3298 SET_REGNO_REG_SET (set, regno);
3301 #ifdef EH_RETURN_STACKADJ_RTX
3302 if ((! HAVE_epilogue || ! reload_completed)
3303 && current_function_calls_eh_return)
3305 rtx tmp = EH_RETURN_STACKADJ_RTX;
3306 if (tmp && REG_P (tmp))
3307 mark_reg (tmp, set);
3310 #ifdef EH_RETURN_HANDLER_RTX
3311 if ((! HAVE_epilogue || ! reload_completed)
3312 && current_function_calls_eh_return)
3314 rtx tmp = EH_RETURN_HANDLER_RTX;
3315 if (tmp && REG_P (tmp))
3316 mark_reg (tmp, set);
3320 /* Mark function return value. */
3321 diddle_return_value (mark_reg, set);
3324 /* Callback function for for_each_successor_phi. DATA is a regset.
3325 Sets the SRC_REGNO, the regno of the phi alternative for phi node
3326 INSN, in the regset. */
3329 set_phi_alternative_reg (insn, dest_regno, src_regno, data)
3330 rtx insn ATTRIBUTE_UNUSED;
3331 int dest_regno ATTRIBUTE_UNUSED;
3335 regset live = (regset) data;
3336 SET_REGNO_REG_SET (live, src_regno);
3340 /* Propagate global life info around the graph of basic blocks. Begin
3341 considering blocks with their corresponding bit set in BLOCKS_IN.
3342 If BLOCKS_IN is null, consider it the universal set.
3344 BLOCKS_OUT is set for every block that was changed. */
3347 calculate_global_regs_live (blocks_in, blocks_out, flags)
3348 sbitmap blocks_in, blocks_out;
3351 basic_block *queue, *qhead, *qtail, *qend;
3352 regset tmp, new_live_at_end, call_used;
3353 regset_head tmp_head, call_used_head;
3354 regset_head new_live_at_end_head;
3357 tmp = INITIALIZE_REG_SET (tmp_head);
3358 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
3359 call_used = INITIALIZE_REG_SET (call_used_head);
3361 /* Inconveniently, this is only redily available in hard reg set form. */
3362 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
3363 if (call_used_regs[i])
3364 SET_REGNO_REG_SET (call_used, i);
3366 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
3367 because the `head == tail' style test for an empty queue doesn't
3368 work with a full queue. */
3369 queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
3371 qhead = qend = queue + n_basic_blocks + 2;
3373 /* Queue the blocks set in the initial mask. Do this in reverse block
3374 number order so that we are more likely for the first round to do
3375 useful work. We use AUX non-null to flag that the block is queued. */
3378 /* Clear out the garbage that might be hanging out in bb->aux. */
3379 for (i = n_basic_blocks - 1; i >= 0; --i)
3380 BASIC_BLOCK (i)->aux = NULL;
3382 EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
3384 basic_block bb = BASIC_BLOCK (i);
3391 for (i = 0; i < n_basic_blocks; ++i)
3393 basic_block bb = BASIC_BLOCK (i);
3400 sbitmap_zero (blocks_out);
3402 /* We work through the queue until there are no more blocks. What
3403 is live at the end of this block is precisely the union of what
3404 is live at the beginning of all its successors. So, we set its
3405 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
3406 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
3407 this block by walking through the instructions in this block in
3408 reverse order and updating as we go. If that changed
3409 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
3410 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
3412 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
3413 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
3414 must either be live at the end of the block, or used within the
3415 block. In the latter case, it will certainly never disappear
3416 from GLOBAL_LIVE_AT_START. In the former case, the register
3417 could go away only if it disappeared from GLOBAL_LIVE_AT_START
3418 for one of the successor blocks. By induction, that cannot
3420 while (qhead != qtail)
3422 int rescan, changed;
3431 /* Begin by propagating live_at_start from the successor blocks. */
3432 CLEAR_REG_SET (new_live_at_end);
3433 for (e = bb->succ; e; e = e->succ_next)
3435 basic_block sb = e->dest;
3437 /* Call-clobbered registers die across exception and call edges. */
3438 /* ??? Abnormal call edges ignored for the moment, as this gets
3439 confused by sibling call edges, which crashes reg-stack. */
3440 if (e->flags & EDGE_EH)
3442 bitmap_operation (tmp, sb->global_live_at_start,
3443 call_used, BITMAP_AND_COMPL);
3444 IOR_REG_SET (new_live_at_end, tmp);
3447 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
3450 /* The all-important stack pointer must always be live. */
3451 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
3453 /* Before reload, there are a few registers that must be forced
3454 live everywhere -- which might not already be the case for
3455 blocks within infinite loops. */
3456 if (! reload_completed)
3458 /* Any reference to any pseudo before reload is a potential
3459 reference of the frame pointer. */
3460 SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
3462 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3463 /* Pseudos with argument area equivalences may require
3464 reloading via the argument pointer. */
3465 if (fixed_regs[ARG_POINTER_REGNUM])
3466 SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
3469 /* Any constant, or pseudo with constant equivalences, may
3470 require reloading from memory using the pic register. */
3471 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
3472 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
3473 SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
3476 /* Regs used in phi nodes are not included in
3477 global_live_at_start, since they are live only along a
3478 particular edge. Set those regs that are live because of a
3479 phi node alternative corresponding to this particular block. */
3481 for_each_successor_phi (bb, &set_phi_alternative_reg,
3484 if (bb == ENTRY_BLOCK_PTR)
3486 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3490 /* On our first pass through this block, we'll go ahead and continue.
3491 Recognize first pass by local_set NULL. On subsequent passes, we
3492 get to skip out early if live_at_end wouldn't have changed. */
3494 if (bb->local_set == NULL)
3496 bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3497 bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3502 /* If any bits were removed from live_at_end, we'll have to
3503 rescan the block. This wouldn't be necessary if we had
3504 precalculated local_live, however with PROP_SCAN_DEAD_CODE
3505 local_live is really dependent on live_at_end. */
3506 CLEAR_REG_SET (tmp);
3507 rescan = bitmap_operation (tmp, bb->global_live_at_end,
3508 new_live_at_end, BITMAP_AND_COMPL);
3512 /* If any of the registers in the new live_at_end set are
3513 conditionally set in this basic block, we must rescan.
3514 This is because conditional lifetimes at the end of the
3515 block do not just take the live_at_end set into account,
3516 but also the liveness at the start of each successor
3517 block. We can miss changes in those sets if we only
3518 compare the new live_at_end against the previous one. */
3519 CLEAR_REG_SET (tmp);
3520 rescan = bitmap_operation (tmp, new_live_at_end,
3521 bb->cond_local_set, BITMAP_AND);
3526 /* Find the set of changed bits. Take this opportunity
3527 to notice that this set is empty and early out. */
3528 CLEAR_REG_SET (tmp);
3529 changed = bitmap_operation (tmp, bb->global_live_at_end,
3530 new_live_at_end, BITMAP_XOR);
3534 /* If any of the changed bits overlap with local_set,
3535 we'll have to rescan the block. Detect overlap by
3536 the AND with ~local_set turning off bits. */
3537 rescan = bitmap_operation (tmp, tmp, bb->local_set,
3542 /* Let our caller know that BB changed enough to require its
3543 death notes updated. */
3545 SET_BIT (blocks_out, bb->index);
3549 /* Add to live_at_start the set of all registers in
3550 new_live_at_end that aren't in the old live_at_end. */
3552 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
3554 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3556 changed = bitmap_operation (bb->global_live_at_start,
3557 bb->global_live_at_start,
3564 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3566 /* Rescan the block insn by insn to turn (a copy of) live_at_end
3567 into live_at_start. */
3568 propagate_block (bb, new_live_at_end, bb->local_set,
3569 bb->cond_local_set, flags);
3571 /* If live_at start didn't change, no need to go farther. */
3572 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
3575 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
3578 /* Queue all predecessors of BB so that we may re-examine
3579 their live_at_end. */
3580 for (e = bb->pred; e; e = e->pred_next)
3582 basic_block pb = e->src;
3583 if (pb->aux == NULL)
3594 FREE_REG_SET (new_live_at_end);
3595 FREE_REG_SET (call_used);
3599 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
3601 basic_block bb = BASIC_BLOCK (i);
3602 FREE_REG_SET (bb->local_set);
3603 FREE_REG_SET (bb->cond_local_set);
3608 for (i = n_basic_blocks - 1; i >= 0; --i)
3610 basic_block bb = BASIC_BLOCK (i);
3611 FREE_REG_SET (bb->local_set);
3612 FREE_REG_SET (bb->cond_local_set);
3619 /* Subroutines of life analysis. */
3621 /* Allocate the permanent data structures that represent the results
3622 of life analysis. Not static since used also for stupid life analysis. */
3625 allocate_bb_life_data ()
3629 for (i = 0; i < n_basic_blocks; i++)
3631 basic_block bb = BASIC_BLOCK (i);
3633 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3634 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3637 ENTRY_BLOCK_PTR->global_live_at_end
3638 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3639 EXIT_BLOCK_PTR->global_live_at_start
3640 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3642 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3646 allocate_reg_life_data ()
3650 max_regno = max_reg_num ();
3652 /* Recalculate the register space, in case it has grown. Old style
3653 vector oriented regsets would set regset_{size,bytes} here also. */
3654 allocate_reg_info (max_regno, FALSE, FALSE);
3656 /* Reset all the data we'll collect in propagate_block and its
3658 for (i = 0; i < max_regno; i++)
3662 REG_N_DEATHS (i) = 0;
3663 REG_N_CALLS_CROSSED (i) = 0;
3664 REG_LIVE_LENGTH (i) = 0;
3665 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
3669 /* Delete dead instructions for propagate_block. */
3672 propagate_block_delete_insn (bb, insn)
3676 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
3678 /* If the insn referred to a label, and that label was attached to
3679 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
3680 pretty much mandatory to delete it, because the ADDR_VEC may be
3681 referencing labels that no longer exist.
3683 INSN may reference a deleted label, particularly when a jump
3684 table has been optimized into a direct jump. There's no
3685 real good way to fix up the reference to the deleted label
3686 when the label is deleted, so we just allow it here.
3688 After dead code elimination is complete, we do search for
3689 any REG_LABEL notes which reference deleted labels as a
3692 if (inote && GET_CODE (inote) == CODE_LABEL)
3694 rtx label = XEXP (inote, 0);
3697 /* The label may be forced if it has been put in the constant
3698 pool. If that is the only use we must discard the table
3699 jump following it, but not the label itself. */
3700 if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
3701 && (next = next_nonnote_insn (label)) != NULL
3702 && GET_CODE (next) == JUMP_INSN
3703 && (GET_CODE (PATTERN (next)) == ADDR_VEC
3704 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
3706 rtx pat = PATTERN (next);
3707 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
3708 int len = XVECLEN (pat, diff_vec_p);
3711 for (i = 0; i < len; i++)
3712 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
3714 flow_delete_insn (next);
3718 if (bb->end == insn)
3719 bb->end = PREV_INSN (insn);
3720 flow_delete_insn (insn);
3723 /* Delete dead libcalls for propagate_block. Return the insn
3724 before the libcall. */
3727 propagate_block_delete_libcall (bb, insn, note)
3731 rtx first = XEXP (note, 0);
3732 rtx before = PREV_INSN (first);
3734 if (insn == bb->end)
3737 flow_delete_insn_chain (first, insn);
3741 /* Update the life-status of regs for one insn. Return the previous insn. */
3744 propagate_one_insn (pbi, insn)
3745 struct propagate_block_info *pbi;
3748 rtx prev = PREV_INSN (insn);
3749 int flags = pbi->flags;
3750 int insn_is_dead = 0;
3751 int libcall_is_dead = 0;
3755 if (! INSN_P (insn))
3758 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
3759 if (flags & PROP_SCAN_DEAD_CODE)
3761 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
3762 libcall_is_dead = (insn_is_dead && note != 0
3763 && libcall_dead_p (pbi, note, insn));
3766 /* If an instruction consists of just dead store(s) on final pass,
3768 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
3770 /* If we're trying to delete a prologue or epilogue instruction
3771 that isn't flagged as possibly being dead, something is wrong.
3772 But if we are keeping the stack pointer depressed, we might well
3773 be deleting insns that are used to compute the amount to update
3774 it by, so they are fine. */
3775 if (reload_completed
3776 && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
3777 && (TYPE_RETURNS_STACK_DEPRESSED
3778 (TREE_TYPE (current_function_decl))))
3779 && (((HAVE_epilogue || HAVE_prologue)
3780 && prologue_epilogue_contains (insn))
3781 || (HAVE_sibcall_epilogue
3782 && sibcall_epilogue_contains (insn)))
3783 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
3786 /* Record sets. Do this even for dead instructions, since they
3787 would have killed the values if they hadn't been deleted. */
3788 mark_set_regs (pbi, PATTERN (insn), insn);
3790 /* CC0 is now known to be dead. Either this insn used it,
3791 in which case it doesn't anymore, or clobbered it,
3792 so the next insn can't use it. */
3795 if (libcall_is_dead)
3796 prev = propagate_block_delete_libcall (pbi->bb, insn, note);
3798 propagate_block_delete_insn (pbi->bb, insn);
3803 /* See if this is an increment or decrement that can be merged into
3804 a following memory address. */
3807 register rtx x = single_set (insn);
3809 /* Does this instruction increment or decrement a register? */
3810 if ((flags & PROP_AUTOINC)
3812 && GET_CODE (SET_DEST (x)) == REG
3813 && (GET_CODE (SET_SRC (x)) == PLUS
3814 || GET_CODE (SET_SRC (x)) == MINUS)
3815 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
3816 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
3817 /* Ok, look for a following memory ref we can combine with.
3818 If one is found, change the memory ref to a PRE_INC
3819 or PRE_DEC, cancel this insn, and return 1.
3820 Return 0 if nothing has been done. */
3821 && try_pre_increment_1 (pbi, insn))
3824 #endif /* AUTO_INC_DEC */
3826 CLEAR_REG_SET (pbi->new_set);
3828 /* If this is not the final pass, and this insn is copying the value of
3829 a library call and it's dead, don't scan the insns that perform the
3830 library call, so that the call's arguments are not marked live. */
3831 if (libcall_is_dead)
3833 /* Record the death of the dest reg. */
3834 mark_set_regs (pbi, PATTERN (insn), insn);
3836 insn = XEXP (note, 0);
3837 return PREV_INSN (insn);
3839 else if (GET_CODE (PATTERN (insn)) == SET
3840 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
3841 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
3842 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
3843 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
3844 /* We have an insn to pop a constant amount off the stack.
3845 (Such insns use PLUS regardless of the direction of the stack,
3846 and any insn to adjust the stack by a constant is always a pop.)
3847 These insns, if not dead stores, have no effect on life. */
3851 /* Any regs live at the time of a call instruction must not go
3852 in a register clobbered by calls. Find all regs now live and
3853 record this for them. */
3855 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
3856 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
3857 { REG_N_CALLS_CROSSED (i)++; });
3859 /* Record sets. Do this even for dead instructions, since they
3860 would have killed the values if they hadn't been deleted. */
3861 mark_set_regs (pbi, PATTERN (insn), insn);
3863 if (GET_CODE (insn) == CALL_INSN)
3869 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
3870 cond = COND_EXEC_TEST (PATTERN (insn));
3872 /* Non-constant calls clobber memory. */
3873 if (! CONST_CALL_P (insn))
3875 free_EXPR_LIST_list (&pbi->mem_set_list);
3876 pbi->mem_set_list_len = 0;
3879 /* There may be extra registers to be clobbered. */
3880 for (note = CALL_INSN_FUNCTION_USAGE (insn);
3882 note = XEXP (note, 1))
3883 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
3884 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
3885 cond, insn, pbi->flags);
3887 /* Calls change all call-used and global registers. */
3888 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3889 if (call_used_regs[i] && ! global_regs[i]
3892 /* We do not want REG_UNUSED notes for these registers. */
3893 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
3895 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
3899 /* If an insn doesn't use CC0, it becomes dead since we assume
3900 that every insn clobbers it. So show it dead here;
3901 mark_used_regs will set it live if it is referenced. */
3906 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
3908 /* Sometimes we may have inserted something before INSN (such as a move)
3909 when we make an auto-inc. So ensure we will scan those insns. */
3911 prev = PREV_INSN (insn);
3914 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
3920 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
3921 cond = COND_EXEC_TEST (PATTERN (insn));
3923 /* Calls use their arguments. */
3924 for (note = CALL_INSN_FUNCTION_USAGE (insn);
3926 note = XEXP (note, 1))
3927 if (GET_CODE (XEXP (note, 0)) == USE)
3928 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
3931 /* The stack ptr is used (honorarily) by a CALL insn. */
3932 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
3934 /* Calls may also reference any of the global registers,
3935 so they are made live. */
3936 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3938 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
3943 /* On final pass, update counts of how many insns in which each reg
3945 if (flags & PROP_REG_INFO)
3946 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
3947 { REG_LIVE_LENGTH (i)++; });
3952 /* Initialize a propagate_block_info struct for public consumption.
3953 Note that the structure itself is opaque to this file, but that
3954 the user can use the regsets provided here. */
3956 struct propagate_block_info *
3957 init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
3959 regset live, local_set, cond_local_set;
3962 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
3965 pbi->reg_live = live;
3966 pbi->mem_set_list = NULL_RTX;
3967 pbi->mem_set_list_len = 0;
3968 pbi->local_set = local_set;
3969 pbi->cond_local_set = cond_local_set;
3973 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
3974 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
3976 pbi->reg_next_use = NULL;
3978 pbi->new_set = BITMAP_XMALLOC ();
3980 #ifdef HAVE_conditional_execution
3981 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
3982 free_reg_cond_life_info);
3983 pbi->reg_cond_reg = BITMAP_XMALLOC ();
3985 /* If this block ends in a conditional branch, for each register live
3986 from one side of the branch and not the other, record the register
3987 as conditionally dead. */
3988 if (GET_CODE (bb->end) == JUMP_INSN
3989 && any_condjump_p (bb->end))
3991 regset_head diff_head;
3992 regset diff = INITIALIZE_REG_SET (diff_head);
3993 basic_block bb_true, bb_false;
3994 rtx cond_true, cond_false, set_src;
3997 /* Identify the successor blocks. */
3998 bb_true = bb->succ->dest;
3999 if (bb->succ->succ_next != NULL)
4001 bb_false = bb->succ->succ_next->dest;
4003 if (bb->succ->flags & EDGE_FALLTHRU)
4005 basic_block t = bb_false;
4009 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
4014 /* This can happen with a conditional jump to the next insn. */
4015 if (JUMP_LABEL (bb->end) != bb_true->head)
4018 /* Simplest way to do nothing. */
4022 /* Extract the condition from the branch. */
4023 set_src = SET_SRC (pc_set (bb->end));
4024 cond_true = XEXP (set_src, 0);
4025 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
4026 GET_MODE (cond_true), XEXP (cond_true, 0),
4027 XEXP (cond_true, 1));
4028 if (GET_CODE (XEXP (set_src, 1)) == PC)
4031 cond_false = cond_true;
4035 /* Compute which register lead different lives in the successors. */
4036 if (bitmap_operation (diff, bb_true->global_live_at_start,
4037 bb_false->global_live_at_start, BITMAP_XOR))
4039 rtx reg = XEXP (cond_true, 0);
4041 if (GET_CODE (reg) == SUBREG)
4042 reg = SUBREG_REG (reg);
4044 if (GET_CODE (reg) != REG)
4047 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
4049 /* For each such register, mark it conditionally dead. */
4050 EXECUTE_IF_SET_IN_REG_SET
4053 struct reg_cond_life_info *rcli;
4056 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
4058 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
4062 rcli->condition = cond;
4063 rcli->stores = const0_rtx;
4064 rcli->orig_condition = cond;
4066 splay_tree_insert (pbi->reg_cond_dead, i,
4067 (splay_tree_value) rcli);
4071 FREE_REG_SET (diff);
4075 /* If this block has no successors, any stores to the frame that aren't
4076 used later in the block are dead. So make a pass over the block
4077 recording any such that are made and show them dead at the end. We do
4078 a very conservative and simple job here. */
4080 && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
4081 && (TYPE_RETURNS_STACK_DEPRESSED
4082 (TREE_TYPE (current_function_decl))))
4083 && (flags & PROP_SCAN_DEAD_CODE)
4084 && (bb->succ == NULL
4085 || (bb->succ->succ_next == NULL
4086 && bb->succ->dest == EXIT_BLOCK_PTR
4087 && ! current_function_calls_eh_return)))
4090 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
4091 if (GET_CODE (insn) == INSN
4092 && (set = single_set (insn))
4093 && GET_CODE (SET_DEST (set)) == MEM)
4095 rtx mem = SET_DEST (set);
4096 rtx canon_mem = canon_rtx (mem);
4098 /* This optimization is performed by faking a store to the
4099 memory at the end of the block. This doesn't work for
4100 unchanging memories because multiple stores to unchanging
4101 memory is illegal and alias analysis doesn't consider it. */
4102 if (RTX_UNCHANGING_P (canon_mem))
4105 if (XEXP (canon_mem, 0) == frame_pointer_rtx
4106 || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
4107 && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
4108 && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
4111 /* Store a copy of mem, otherwise the address may be scrogged
4112 by find_auto_inc. This matters because insn_dead_p uses
4113 an rtx_equal_p check to determine if two addresses are
4114 the same. This works before find_auto_inc, but fails
4115 after find_auto_inc, causing discrepencies between the
4116 set of live registers calculated during the
4117 calculate_global_regs_live phase and what actually exists
4118 after flow completes, leading to aborts. */
4119 if (flags & PROP_AUTOINC)
4120 mem = shallow_copy_rtx (mem);
4122 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
4123 if (++pbi->mem_set_list_len >= MAX_MEM_SET_LIST_LEN)
4132 /* Release a propagate_block_info struct. */
4135 free_propagate_block_info (pbi)
4136 struct propagate_block_info *pbi;
4138 free_EXPR_LIST_list (&pbi->mem_set_list);
4140 BITMAP_XFREE (pbi->new_set);
4142 #ifdef HAVE_conditional_execution
4143 splay_tree_delete (pbi->reg_cond_dead);
4144 BITMAP_XFREE (pbi->reg_cond_reg);
4147 if (pbi->reg_next_use)
4148 free (pbi->reg_next_use);
4153 /* Compute the registers live at the beginning of a basic block BB from
4154 those live at the end.
4156 When called, REG_LIVE contains those live at the end. On return, it
4157 contains those live at the beginning.
4159 LOCAL_SET, if non-null, will be set with all registers killed
4160 unconditionally by this basic block.
4161 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
4162 killed conditionally by this basic block. If there is any unconditional
4163 set of a register, then the corresponding bit will be set in LOCAL_SET
4164 and cleared in COND_LOCAL_SET.
4165 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
4166 case, the resulting set will be equal to the union of the two sets that
4167 would otherwise be computed. */
4170 propagate_block (bb, live, local_set, cond_local_set, flags)
4174 regset cond_local_set;
4177 struct propagate_block_info *pbi;
4180 pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
4182 if (flags & PROP_REG_INFO)
4186 /* Process the regs live at the end of the block.
4187 Mark them as not local to any one basic block. */
4188 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
4189 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
4192 /* Scan the block an insn at a time from end to beginning. */
4194 for (insn = bb->end;; insn = prev)
4196 /* If this is a call to `setjmp' et al, warn if any
4197 non-volatile datum is live. */
4198 if ((flags & PROP_REG_INFO)
4199 && GET_CODE (insn) == NOTE
4200 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
4201 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
4203 prev = propagate_one_insn (pbi, insn);
4205 if (insn == bb->head)
4209 free_propagate_block_info (pbi);
4212 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
4213 (SET expressions whose destinations are registers dead after the insn).
4214 NEEDED is the regset that says which regs are alive after the insn.
4216 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
4218 If X is the entire body of an insn, NOTES contains the reg notes
4219 pertaining to the insn. */
4222 insn_dead_p (pbi, x, call_ok, notes)
4223 struct propagate_block_info *pbi;
4226 rtx notes ATTRIBUTE_UNUSED;
4228 enum rtx_code code = GET_CODE (x);
4231 /* If flow is invoked after reload, we must take existing AUTO_INC
4232 expresions into account. */
4233 if (reload_completed)
4235 for (; notes; notes = XEXP (notes, 1))
4237 if (REG_NOTE_KIND (notes) == REG_INC)
4239 int regno = REGNO (XEXP (notes, 0));
4241 /* Don't delete insns to set global regs. */
4242 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
4243 || REGNO_REG_SET_P (pbi->reg_live, regno))
4250 /* If setting something that's a reg or part of one,
4251 see if that register's altered value will be live. */
4255 rtx r = SET_DEST (x);
4258 if (GET_CODE (r) == CC0)
4259 return ! pbi->cc0_live;
4262 /* A SET that is a subroutine call cannot be dead. */
4263 if (GET_CODE (SET_SRC (x)) == CALL)
4269 /* Don't eliminate loads from volatile memory or volatile asms. */
4270 else if (volatile_refs_p (SET_SRC (x)))
4273 if (GET_CODE (r) == MEM)
4277 if (MEM_VOLATILE_P (r))
4280 /* Walk the set of memory locations we are currently tracking
4281 and see if one is an identical match to this memory location.
4282 If so, this memory write is dead (remember, we're walking
4283 backwards from the end of the block to the start). Since
4284 rtx_equal_p does not check the alias set or flags, we also
4285 must have the potential for them to conflict (anti_dependence). */
4286 for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
4287 if (anti_dependence (r, XEXP (temp, 0)))
4289 rtx mem = XEXP (temp, 0);
4291 if (rtx_equal_p (mem, r))
4294 /* Check if memory reference matches an auto increment. Only
4295 post increment/decrement or modify are valid. */
4296 if (GET_MODE (mem) == GET_MODE (r)
4297 && (GET_CODE (XEXP (mem, 0)) == POST_DEC
4298 || GET_CODE (XEXP (mem, 0)) == POST_INC
4299 || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
4300 && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
4301 && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
4308 while (GET_CODE (r) == SUBREG
4309 || GET_CODE (r) == STRICT_LOW_PART
4310 || GET_CODE (r) == ZERO_EXTRACT)
4313 if (GET_CODE (r) == REG)
4315 int regno = REGNO (r);
4318 if (REGNO_REG_SET_P (pbi->reg_live, regno))
4321 /* If this is a hard register, verify that subsequent
4322 words are not needed. */
4323 if (regno < FIRST_PSEUDO_REGISTER)
4325 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
4328 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
4332 /* Don't delete insns to set global regs. */
4333 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
4336 /* Make sure insns to set the stack pointer aren't deleted. */
4337 if (regno == STACK_POINTER_REGNUM)
4340 /* ??? These bits might be redundant with the force live bits
4341 in calculate_global_regs_live. We would delete from
4342 sequential sets; whether this actually affects real code
4343 for anything but the stack pointer I don't know. */
4344 /* Make sure insns to set the frame pointer aren't deleted. */
4345 if (regno == FRAME_POINTER_REGNUM
4346 && (! reload_completed || frame_pointer_needed))
4348 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4349 if (regno == HARD_FRAME_POINTER_REGNUM
4350 && (! reload_completed || frame_pointer_needed))
4354 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4355 /* Make sure insns to set arg pointer are never deleted
4356 (if the arg pointer isn't fixed, there will be a USE
4357 for it, so we can treat it normally). */
4358 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
4362 /* Otherwise, the set is dead. */
4368 /* If performing several activities, insn is dead if each activity
4369 is individually dead. Also, CLOBBERs and USEs can be ignored; a
4370 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
4372 else if (code == PARALLEL)
4374 int i = XVECLEN (x, 0);
4376 for (i--; i >= 0; i--)
4377 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
4378 && GET_CODE (XVECEXP (x, 0, i)) != USE
4379 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
4385 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
4386 is not necessarily true for hard registers. */
4387 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
4388 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
4389 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
4392 /* We do not check other CLOBBER or USE here. An insn consisting of just
4393 a CLOBBER or just a USE should not be deleted. */
4397 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
4398 return 1 if the entire library call is dead.
4399 This is true if INSN copies a register (hard or pseudo)
4400 and if the hard return reg of the call insn is dead.
4401 (The caller should have tested the destination of the SET inside
4402 INSN already for death.)
4404 If this insn doesn't just copy a register, then we don't
4405 have an ordinary libcall. In that case, cse could not have
4406 managed to substitute the source for the dest later on,
4407 so we can assume the libcall is dead.
4409 PBI is the block info giving pseudoregs live before this insn.
4410 NOTE is the REG_RETVAL note of the insn. */
4413 libcall_dead_p (pbi, note, insn)
4414 struct propagate_block_info *pbi;
4418 rtx x = single_set (insn);
4422 register rtx r = SET_SRC (x);
4423 if (GET_CODE (r) == REG)
4425 rtx call = XEXP (note, 0);
4429 /* Find the call insn. */
4430 while (call != insn && GET_CODE (call) != CALL_INSN)
4431 call = NEXT_INSN (call);
4433 /* If there is none, do nothing special,
4434 since ordinary death handling can understand these insns. */
4438 /* See if the hard reg holding the value is dead.
4439 If this is a PARALLEL, find the call within it. */
4440 call_pat = PATTERN (call);
4441 if (GET_CODE (call_pat) == PARALLEL)
4443 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
4444 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
4445 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
4448 /* This may be a library call that is returning a value
4449 via invisible pointer. Do nothing special, since
4450 ordinary death handling can understand these insns. */
4454 call_pat = XVECEXP (call_pat, 0, i);
4457 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
4463 /* Return 1 if register REGNO was used before it was set, i.e. if it is
4464 live at function entry. Don't count global register variables, variables
4465 in registers that can be used for function arg passing, or variables in
4466 fixed hard registers. */
4469 regno_uninitialized (regno)
4472 if (n_basic_blocks == 0
4473 || (regno < FIRST_PSEUDO_REGISTER
4474 && (global_regs[regno]
4475 || fixed_regs[regno]
4476 || FUNCTION_ARG_REGNO_P (regno))))
4479 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
4482 /* 1 if register REGNO was alive at a place where `setjmp' was called
4483 and was set more than once or is an argument.
4484 Such regs may be clobbered by `longjmp'. */
4487 regno_clobbered_at_setjmp (regno)
4490 if (n_basic_blocks == 0)
4493 return ((REG_N_SETS (regno) > 1
4494 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
4495 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
4498 /* INSN references memory, possibly using autoincrement addressing modes.
4499 Find any entries on the mem_set_list that need to be invalidated due
4500 to an address change. */
4503 invalidate_mems_from_autoinc (pbi, insn)
4504 struct propagate_block_info *pbi;
4507 rtx note = REG_NOTES (insn);
4508 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
4510 if (REG_NOTE_KIND (note) == REG_INC)
4512 rtx temp = pbi->mem_set_list;
4513 rtx prev = NULL_RTX;
4518 next = XEXP (temp, 1);
4519 if (reg_overlap_mentioned_p (XEXP (note, 0), XEXP (temp, 0)))
4521 /* Splice temp out of list. */
4523 XEXP (prev, 1) = next;
4525 pbi->mem_set_list = next;
4526 free_EXPR_LIST_node (temp);
4527 pbi->mem_set_list_len--;
4537 /* EXP is either a MEM or a REG. Remove any dependant entries
4538 from pbi->mem_set_list. */
4541 invalidate_mems_from_set (pbi, exp)
4542 struct propagate_block_info *pbi;
4545 rtx temp = pbi->mem_set_list;
4546 rtx prev = NULL_RTX;
4551 next = XEXP (temp, 1);
4552 if ((GET_CODE (exp) == MEM
4553 && output_dependence (XEXP (temp, 0), exp))
4554 || (GET_CODE (exp) == REG
4555 && reg_overlap_mentioned_p (exp, XEXP (temp, 0))))
4557 /* Splice this entry out of the list. */
4559 XEXP (prev, 1) = next;
4561 pbi->mem_set_list = next;
4562 free_EXPR_LIST_node (temp);
4563 pbi->mem_set_list_len--;
4571 /* Process the registers that are set within X. Their bits are set to
4572 1 in the regset DEAD, because they are dead prior to this insn.
4574 If INSN is nonzero, it is the insn being processed.
4576 FLAGS is the set of operations to perform. */
4579 mark_set_regs (pbi, x, insn)
4580 struct propagate_block_info *pbi;
4583 rtx cond = NULL_RTX;
4588 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
4590 if (REG_NOTE_KIND (link) == REG_INC)
4591 mark_set_1 (pbi, SET, XEXP (link, 0),
4592 (GET_CODE (x) == COND_EXEC
4593 ? COND_EXEC_TEST (x) : NULL_RTX),
4597 switch (code = GET_CODE (x))
4601 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
4605 cond = COND_EXEC_TEST (x);
4606 x = COND_EXEC_CODE (x);
4612 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
4614 rtx sub = XVECEXP (x, 0, i);
4615 switch (code = GET_CODE (sub))
4618 if (cond != NULL_RTX)
4621 cond = COND_EXEC_TEST (sub);
4622 sub = COND_EXEC_CODE (sub);
4623 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
4629 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
4644 /* Process a single set, which appears in INSN. REG (which may not
4645 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
4646 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
4647 If the set is conditional (because it appear in a COND_EXEC), COND
4648 will be the condition. */
4651 mark_set_1 (pbi, code, reg, cond, insn, flags)
4652 struct propagate_block_info *pbi;
4654 rtx reg, cond, insn;
4657 int regno_first = -1, regno_last = -1;
4658 unsigned long not_dead = 0;
4661 /* Modifying just one hardware register of a multi-reg value or just a
4662 byte field of a register does not mean the value from before this insn
4663 is now dead. Of course, if it was dead after it's unused now. */
4665 switch (GET_CODE (reg))
4668 /* Some targets place small structures in registers for return values of
4669 functions. We have to detect this case specially here to get correct
4670 flow information. */
4671 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
4672 if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
4673 mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
4679 case STRICT_LOW_PART:
4680 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
4682 reg = XEXP (reg, 0);
4683 while (GET_CODE (reg) == SUBREG
4684 || GET_CODE (reg) == ZERO_EXTRACT
4685 || GET_CODE (reg) == SIGN_EXTRACT
4686 || GET_CODE (reg) == STRICT_LOW_PART);
4687 if (GET_CODE (reg) == MEM)
4689 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
4693 regno_last = regno_first = REGNO (reg);
4694 if (regno_first < FIRST_PSEUDO_REGISTER)
4695 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
4699 if (GET_CODE (SUBREG_REG (reg)) == REG)
4701 enum machine_mode outer_mode = GET_MODE (reg);
4702 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
4704 /* Identify the range of registers affected. This is moderately
4705 tricky for hard registers. See alter_subreg. */
4707 regno_last = regno_first = REGNO (SUBREG_REG (reg));
4708 if (regno_first < FIRST_PSEUDO_REGISTER)
4710 regno_first += subreg_regno_offset (regno_first, inner_mode,
4713 regno_last = (regno_first
4714 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
4716 /* Since we've just adjusted the register number ranges, make
4717 sure REG matches. Otherwise some_was_live will be clear
4718 when it shouldn't have been, and we'll create incorrect
4719 REG_UNUSED notes. */
4720 reg = gen_rtx_REG (outer_mode, regno_first);
4724 /* If the number of words in the subreg is less than the number
4725 of words in the full register, we have a well-defined partial
4726 set. Otherwise the high bits are undefined.
4728 This is only really applicable to pseudos, since we just took
4729 care of multi-word hard registers. */
4730 if (((GET_MODE_SIZE (outer_mode)
4731 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
4732 < ((GET_MODE_SIZE (inner_mode)
4733 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
4734 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
4737 reg = SUBREG_REG (reg);
4741 reg = SUBREG_REG (reg);
4748 /* If this set is a MEM, then it kills any aliased writes.
4749 If this set is a REG, then it kills any MEMs which use the reg. */
4750 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
4752 if (GET_CODE (reg) == MEM || GET_CODE (reg) == REG)
4753 invalidate_mems_from_set (pbi, reg);
4755 /* If the memory reference had embedded side effects (autoincrement
4756 address modes. Then we may need to kill some entries on the
4758 if (insn && GET_CODE (reg) == MEM)
4759 invalidate_mems_from_autoinc (pbi, insn);
4761 if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN
4762 && GET_CODE (reg) == MEM && ! side_effects_p (reg)
4763 /* ??? With more effort we could track conditional memory life. */
4765 /* We do not know the size of a BLKmode store, so we do not track
4766 them for redundant store elimination. */
4767 && GET_MODE (reg) != BLKmode
4768 /* There are no REG_INC notes for SP, so we can't assume we'll see
4769 everything that invalidates it. To be safe, don't eliminate any
4770 stores though SP; none of them should be redundant anyway. */
4771 && ! reg_mentioned_p (stack_pointer_rtx, reg))
4774 /* Store a copy of mem, otherwise the address may be
4775 scrogged by find_auto_inc. */
4776 if (flags & PROP_AUTOINC)
4777 reg = shallow_copy_rtx (reg);
4779 pbi->mem_set_list = alloc_EXPR_LIST (0, reg, pbi->mem_set_list);
4780 pbi->mem_set_list_len++;
4784 if (GET_CODE (reg) == REG
4785 && ! (regno_first == FRAME_POINTER_REGNUM
4786 && (! reload_completed || frame_pointer_needed))
4787 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4788 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
4789 && (! reload_completed || frame_pointer_needed))
4791 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4792 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
4796 int some_was_live = 0, some_was_dead = 0;
4798 for (i = regno_first; i <= regno_last; ++i)
4800 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
4803 /* Order of the set operation matters here since both
4804 sets may be the same. */
4805 CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
4806 if (cond != NULL_RTX
4807 && ! REGNO_REG_SET_P (pbi->local_set, i))
4808 SET_REGNO_REG_SET (pbi->cond_local_set, i);
4810 SET_REGNO_REG_SET (pbi->local_set, i);
4812 if (code != CLOBBER)
4813 SET_REGNO_REG_SET (pbi->new_set, i);
4815 some_was_live |= needed_regno;
4816 some_was_dead |= ! needed_regno;
4819 #ifdef HAVE_conditional_execution
4820 /* Consider conditional death in deciding that the register needs
4822 if (some_was_live && ! not_dead
4823 /* The stack pointer is never dead. Well, not strictly true,
4824 but it's very difficult to tell from here. Hopefully
4825 combine_stack_adjustments will fix up the most egregious
4827 && regno_first != STACK_POINTER_REGNUM)
4829 for (i = regno_first; i <= regno_last; ++i)
4830 if (! mark_regno_cond_dead (pbi, i, cond))
4831 not_dead |= ((unsigned long) 1) << (i - regno_first);
4835 /* Additional data to record if this is the final pass. */
4836 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
4837 | PROP_DEATH_NOTES | PROP_AUTOINC))
4840 register int blocknum = pbi->bb->index;
4843 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4845 y = pbi->reg_next_use[regno_first];
4847 /* The next use is no longer next, since a store intervenes. */
4848 for (i = regno_first; i <= regno_last; ++i)
4849 pbi->reg_next_use[i] = 0;
4852 if (flags & PROP_REG_INFO)
4854 for (i = regno_first; i <= regno_last; ++i)
4856 /* Count (weighted) references, stores, etc. This counts a
4857 register twice if it is modified, but that is correct. */
4858 REG_N_SETS (i) += 1;
4859 REG_N_REFS (i) += 1;
4860 REG_FREQ (i) += (optimize_size ? 1 : pbi->bb->loop_depth + 1);
4862 /* The insns where a reg is live are normally counted
4863 elsewhere, but we want the count to include the insn
4864 where the reg is set, and the normal counting mechanism
4865 would not count it. */
4866 REG_LIVE_LENGTH (i) += 1;
4869 /* If this is a hard reg, record this function uses the reg. */
4870 if (regno_first < FIRST_PSEUDO_REGISTER)
4872 for (i = regno_first; i <= regno_last; i++)
4873 regs_ever_live[i] = 1;
4877 /* Keep track of which basic blocks each reg appears in. */
4878 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
4879 REG_BASIC_BLOCK (regno_first) = blocknum;
4880 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
4881 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
4885 if (! some_was_dead)
4887 if (flags & PROP_LOG_LINKS)
4889 /* Make a logical link from the next following insn
4890 that uses this register, back to this insn.
4891 The following insns have already been processed.
4893 We don't build a LOG_LINK for hard registers containing
4894 in ASM_OPERANDs. If these registers get replaced,
4895 we might wind up changing the semantics of the insn,
4896 even if reload can make what appear to be valid
4897 assignments later. */
4898 if (y && (BLOCK_NUM (y) == blocknum)
4899 && (regno_first >= FIRST_PSEUDO_REGISTER
4900 || asm_noperands (PATTERN (y)) < 0))
4901 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
4906 else if (! some_was_live)
4908 if (flags & PROP_REG_INFO)
4909 REG_N_DEATHS (regno_first) += 1;
4911 if (flags & PROP_DEATH_NOTES)
4913 /* Note that dead stores have already been deleted
4914 when possible. If we get here, we have found a
4915 dead store that cannot be eliminated (because the
4916 same insn does something useful). Indicate this
4917 by marking the reg being set as dying here. */
4919 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
4924 if (flags & PROP_DEATH_NOTES)
4926 /* This is a case where we have a multi-word hard register
4927 and some, but not all, of the words of the register are
4928 needed in subsequent insns. Write REG_UNUSED notes
4929 for those parts that were not needed. This case should
4932 for (i = regno_first; i <= regno_last; ++i)
4933 if (! REGNO_REG_SET_P (pbi->reg_live, i))
4935 = alloc_EXPR_LIST (REG_UNUSED,
4936 gen_rtx_REG (reg_raw_mode[i], i),
4942 /* Mark the register as being dead. */
4944 /* The stack pointer is never dead. Well, not strictly true,
4945 but it's very difficult to tell from here. Hopefully
4946 combine_stack_adjustments will fix up the most egregious
4948 && regno_first != STACK_POINTER_REGNUM)
4950 for (i = regno_first; i <= regno_last; ++i)
4951 if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
4952 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
4955 else if (GET_CODE (reg) == REG)
4957 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4958 pbi->reg_next_use[regno_first] = 0;
4961 /* If this is the last pass and this is a SCRATCH, show it will be dying
4962 here and count it. */
4963 else if (GET_CODE (reg) == SCRATCH)
4965 if (flags & PROP_DEATH_NOTES)
4967 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
4971 #ifdef HAVE_conditional_execution
4972 /* Mark REGNO conditionally dead.
4973 Return true if the register is now unconditionally dead. */
4976 mark_regno_cond_dead (pbi, regno, cond)
4977 struct propagate_block_info *pbi;
4981 /* If this is a store to a predicate register, the value of the
4982 predicate is changing, we don't know that the predicate as seen
4983 before is the same as that seen after. Flush all dependent
4984 conditions from reg_cond_dead. This will make all such
4985 conditionally live registers unconditionally live. */
4986 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
4987 flush_reg_cond_reg (pbi, regno);
4989 /* If this is an unconditional store, remove any conditional
4990 life that may have existed. */
4991 if (cond == NULL_RTX)
4992 splay_tree_remove (pbi->reg_cond_dead, regno);
4995 splay_tree_node node;
4996 struct reg_cond_life_info *rcli;
4999 /* Otherwise this is a conditional set. Record that fact.
5000 It may have been conditionally used, or there may be a
5001 subsequent set with a complimentary condition. */
5003 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
5006 /* The register was unconditionally live previously.
5007 Record the current condition as the condition under
5008 which it is dead. */
5009 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
5010 rcli->condition = cond;
5011 rcli->stores = cond;
5012 rcli->orig_condition = const0_rtx;
5013 splay_tree_insert (pbi->reg_cond_dead, regno,
5014 (splay_tree_value) rcli);
5016 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5018 /* Not unconditionaly dead. */
5023 /* The register was conditionally live previously.
5024 Add the new condition to the old. */
5025 rcli = (struct reg_cond_life_info *) node->value;
5026 ncond = rcli->condition;
5027 ncond = ior_reg_cond (ncond, cond, 1);
5028 if (rcli->stores == const0_rtx)
5029 rcli->stores = cond;
5030 else if (rcli->stores != const1_rtx)
5031 rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
5033 /* If the register is now unconditionally dead, remove the entry
5034 in the splay_tree. A register is unconditionally dead if the
5035 dead condition ncond is true. A register is also unconditionally
5036 dead if the sum of all conditional stores is an unconditional
5037 store (stores is true), and the dead condition is identically the
5038 same as the original dead condition initialized at the end of
5039 the block. This is a pointer compare, not an rtx_equal_p
5041 if (ncond == const1_rtx
5042 || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
5043 splay_tree_remove (pbi->reg_cond_dead, regno);
5046 rcli->condition = ncond;
5048 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5050 /* Not unconditionaly dead. */
5059 /* Called from splay_tree_delete for pbi->reg_cond_life. */
5062 free_reg_cond_life_info (value)
5063 splay_tree_value value;
5065 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
5069 /* Helper function for flush_reg_cond_reg. */
5072 flush_reg_cond_reg_1 (node, data)
5073 splay_tree_node node;
5076 struct reg_cond_life_info *rcli;
5077 int *xdata = (int *) data;
5078 unsigned int regno = xdata[0];
5080 /* Don't need to search if last flushed value was farther on in
5081 the in-order traversal. */
5082 if (xdata[1] >= (int) node->key)
5085 /* Splice out portions of the expression that refer to regno. */
5086 rcli = (struct reg_cond_life_info *) node->value;
5087 rcli->condition = elim_reg_cond (rcli->condition, regno);
5088 if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
5089 rcli->stores = elim_reg_cond (rcli->stores, regno);
5091 /* If the entire condition is now false, signal the node to be removed. */
5092 if (rcli->condition == const0_rtx)
5094 xdata[1] = node->key;
5097 else if (rcli->condition == const1_rtx)
5103 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
5106 flush_reg_cond_reg (pbi, regno)
5107 struct propagate_block_info *pbi;
5114 while (splay_tree_foreach (pbi->reg_cond_dead,
5115 flush_reg_cond_reg_1, pair) == -1)
5116 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
5118 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
5121 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
5122 For ior/and, the ADD flag determines whether we want to add the new
5123 condition X to the old one unconditionally. If it is zero, we will
5124 only return a new expression if X allows us to simplify part of
5125 OLD, otherwise we return OLD unchanged to the caller.
5126 If ADD is nonzero, we will return a new condition in all cases. The
5127 toplevel caller of one of these functions should always pass 1 for
5131 ior_reg_cond (old, x, add)
5137 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
5139 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
5140 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
5141 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5143 if (GET_CODE (x) == GET_CODE (old)
5144 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5148 return gen_rtx_IOR (0, old, x);
5151 switch (GET_CODE (old))
5154 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
5155 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
5156 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5158 if (op0 == const0_rtx)
5160 if (op1 == const0_rtx)
5162 if (op0 == const1_rtx || op1 == const1_rtx)
5164 if (op0 == XEXP (old, 0))
5165 op0 = gen_rtx_IOR (0, op0, x);
5167 op1 = gen_rtx_IOR (0, op1, x);
5168 return gen_rtx_IOR (0, op0, op1);
5172 return gen_rtx_IOR (0, old, x);
5175 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
5176 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
5177 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5179 if (op0 == const1_rtx)
5181 if (op1 == const1_rtx)
5183 if (op0 == const0_rtx || op1 == const0_rtx)
5185 if (op0 == XEXP (old, 0))
5186 op0 = gen_rtx_IOR (0, op0, x);
5188 op1 = gen_rtx_IOR (0, op1, x);
5189 return gen_rtx_AND (0, op0, op1);
5193 return gen_rtx_IOR (0, old, x);
5196 op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
5197 if (op0 != XEXP (old, 0))
5198 return not_reg_cond (op0);
5201 return gen_rtx_IOR (0, old, x);
5212 enum rtx_code x_code;
5214 if (x == const0_rtx)
5216 else if (x == const1_rtx)
5218 x_code = GET_CODE (x);
5221 if (GET_RTX_CLASS (x_code) == '<'
5222 && GET_CODE (XEXP (x, 0)) == REG)
5224 if (XEXP (x, 1) != const0_rtx)
5227 return gen_rtx_fmt_ee (reverse_condition (x_code),
5228 VOIDmode, XEXP (x, 0), const0_rtx);
5230 return gen_rtx_NOT (0, x);
5234 and_reg_cond (old, x, add)
5240 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
5242 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
5243 && GET_CODE (x) == reverse_condition (GET_CODE (old))
5244 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5246 if (GET_CODE (x) == GET_CODE (old)
5247 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5251 return gen_rtx_AND (0, old, x);
5254 switch (GET_CODE (old))
5257 op0 = and_reg_cond (XEXP (old, 0), x, 0);
5258 op1 = and_reg_cond (XEXP (old, 1), x, 0);
5259 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5261 if (op0 == const0_rtx)
5263 if (op1 == const0_rtx)
5265 if (op0 == const1_rtx || op1 == const1_rtx)
5267 if (op0 == XEXP (old, 0))
5268 op0 = gen_rtx_AND (0, op0, x);
5270 op1 = gen_rtx_AND (0, op1, x);
5271 return gen_rtx_IOR (0, op0, op1);
5275 return gen_rtx_AND (0, old, x);
5278 op0 = and_reg_cond (XEXP (old, 0), x, 0);
5279 op1 = and_reg_cond (XEXP (old, 1), x, 0);
5280 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5282 if (op0 == const1_rtx)
5284 if (op1 == const1_rtx)
5286 if (op0 == const0_rtx || op1 == const0_rtx)
5288 if (op0 == XEXP (old, 0))
5289 op0 = gen_rtx_AND (0, op0, x);
5291 op1 = gen_rtx_AND (0, op1, x);
5292 return gen_rtx_AND (0, op0, op1);
5297 /* If X is identical to one of the existing terms of the AND,
5298 then just return what we already have. */
5299 /* ??? There really should be some sort of recursive check here in
5300 case there are nested ANDs. */
5301 if ((GET_CODE (XEXP (old, 0)) == GET_CODE (x)
5302 && REGNO (XEXP (XEXP (old, 0), 0)) == REGNO (XEXP (x, 0)))
5303 || (GET_CODE (XEXP (old, 1)) == GET_CODE (x)
5304 && REGNO (XEXP (XEXP (old, 1), 0)) == REGNO (XEXP (x, 0))))
5307 return gen_rtx_AND (0, old, x);
5310 op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
5311 if (op0 != XEXP (old, 0))
5312 return not_reg_cond (op0);
5315 return gen_rtx_AND (0, old, x);
5322 /* Given a condition X, remove references to reg REGNO and return the
5323 new condition. The removal will be done so that all conditions
5324 involving REGNO are considered to evaluate to false. This function
5325 is used when the value of REGNO changes. */
5328 elim_reg_cond (x, regno)
5334 if (GET_RTX_CLASS (GET_CODE (x)) == '<')
5336 if (REGNO (XEXP (x, 0)) == regno)
5341 switch (GET_CODE (x))
5344 op0 = elim_reg_cond (XEXP (x, 0), regno);
5345 op1 = elim_reg_cond (XEXP (x, 1), regno);
5346 if (op0 == const0_rtx || op1 == const0_rtx)
5348 if (op0 == const1_rtx)
5350 if (op1 == const1_rtx)
5352 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
5354 return gen_rtx_AND (0, op0, op1);
5357 op0 = elim_reg_cond (XEXP (x, 0), regno);
5358 op1 = elim_reg_cond (XEXP (x, 1), regno);
5359 if (op0 == const1_rtx || op1 == const1_rtx)
5361 if (op0 == const0_rtx)
5363 if (op1 == const0_rtx)
5365 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
5367 return gen_rtx_IOR (0, op0, op1);
5370 op0 = elim_reg_cond (XEXP (x, 0), regno);
5371 if (op0 == const0_rtx)
5373 if (op0 == const1_rtx)
5375 if (op0 != XEXP (x, 0))
5376 return not_reg_cond (op0);
5383 #endif /* HAVE_conditional_execution */
5387 /* Try to substitute the auto-inc expression INC as the address inside
5388 MEM which occurs in INSN. Currently, the address of MEM is an expression
5389 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
5390 that has a single set whose source is a PLUS of INCR_REG and something
5394 attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
5395 struct propagate_block_info *pbi;
5396 rtx inc, insn, mem, incr, incr_reg;
5398 int regno = REGNO (incr_reg);
5399 rtx set = single_set (incr);
5400 rtx q = SET_DEST (set);
5401 rtx y = SET_SRC (set);
5402 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
5404 /* Make sure this reg appears only once in this insn. */
5405 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
5408 if (dead_or_set_p (incr, incr_reg)
5409 /* Mustn't autoinc an eliminable register. */
5410 && (regno >= FIRST_PSEUDO_REGISTER
5411 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
5413 /* This is the simple case. Try to make the auto-inc. If
5414 we can't, we are done. Otherwise, we will do any
5415 needed updates below. */
5416 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
5419 else if (GET_CODE (q) == REG
5420 /* PREV_INSN used here to check the semi-open interval
5422 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
5423 /* We must also check for sets of q as q may be
5424 a call clobbered hard register and there may
5425 be a call between PREV_INSN (insn) and incr. */
5426 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
5428 /* We have *p followed sometime later by q = p+size.
5429 Both p and q must be live afterward,
5430 and q is not used between INSN and its assignment.
5431 Change it to q = p, ...*q..., q = q+size.
5432 Then fall into the usual case. */
5436 emit_move_insn (q, incr_reg);
5437 insns = get_insns ();
5440 if (basic_block_for_insn)
5441 for (temp = insns; temp; temp = NEXT_INSN (temp))
5442 set_block_for_insn (temp, pbi->bb);
5444 /* If we can't make the auto-inc, or can't make the
5445 replacement into Y, exit. There's no point in making
5446 the change below if we can't do the auto-inc and doing
5447 so is not correct in the pre-inc case. */
5450 validate_change (insn, &XEXP (mem, 0), inc, 1);
5451 validate_change (incr, &XEXP (y, opnum), q, 1);
5452 if (! apply_change_group ())
5455 /* We now know we'll be doing this change, so emit the
5456 new insn(s) and do the updates. */
5457 emit_insns_before (insns, insn);
5459 if (pbi->bb->head == insn)
5460 pbi->bb->head = insns;
5462 /* INCR will become a NOTE and INSN won't contain a
5463 use of INCR_REG. If a use of INCR_REG was just placed in
5464 the insn before INSN, make that the next use.
5465 Otherwise, invalidate it. */
5466 if (GET_CODE (PREV_INSN (insn)) == INSN
5467 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
5468 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
5469 pbi->reg_next_use[regno] = PREV_INSN (insn);
5471 pbi->reg_next_use[regno] = 0;
5476 /* REGNO is now used in INCR which is below INSN, but
5477 it previously wasn't live here. If we don't mark
5478 it as live, we'll put a REG_DEAD note for it
5479 on this insn, which is incorrect. */
5480 SET_REGNO_REG_SET (pbi->reg_live, regno);
5482 /* If there are any calls between INSN and INCR, show
5483 that REGNO now crosses them. */
5484 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
5485 if (GET_CODE (temp) == CALL_INSN)
5486 REG_N_CALLS_CROSSED (regno)++;
5491 /* If we haven't returned, it means we were able to make the
5492 auto-inc, so update the status. First, record that this insn
5493 has an implicit side effect. */
5495 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
5497 /* Modify the old increment-insn to simply copy
5498 the already-incremented value of our register. */
5499 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
5502 /* If that makes it a no-op (copying the register into itself) delete
5503 it so it won't appear to be a "use" and a "set" of this
5505 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
5507 /* If the original source was dead, it's dead now. */
5510 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
5512 remove_note (incr, note);
5513 if (XEXP (note, 0) != incr_reg)
5514 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
5517 PUT_CODE (incr, NOTE);
5518 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
5519 NOTE_SOURCE_FILE (incr) = 0;
5522 if (regno >= FIRST_PSEUDO_REGISTER)
5524 /* Count an extra reference to the reg. When a reg is
5525 incremented, spilling it is worse, so we want to make
5526 that less likely. */
5527 REG_FREQ (regno) += (optimize_size ? 1 : pbi->bb->loop_depth + 1);
5529 /* Count the increment as a setting of the register,
5530 even though it isn't a SET in rtl. */
5531 REG_N_SETS (regno)++;
5535 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
5539 find_auto_inc (pbi, x, insn)
5540 struct propagate_block_info *pbi;
5544 rtx addr = XEXP (x, 0);
5545 HOST_WIDE_INT offset = 0;
5546 rtx set, y, incr, inc_val;
5548 int size = GET_MODE_SIZE (GET_MODE (x));
5550 if (GET_CODE (insn) == JUMP_INSN)
5553 /* Here we detect use of an index register which might be good for
5554 postincrement, postdecrement, preincrement, or predecrement. */
5556 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
5557 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
5559 if (GET_CODE (addr) != REG)
5562 regno = REGNO (addr);
5564 /* Is the next use an increment that might make auto-increment? */
5565 incr = pbi->reg_next_use[regno];
5566 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
5568 set = single_set (incr);
5569 if (set == 0 || GET_CODE (set) != SET)
5573 if (GET_CODE (y) != PLUS)
5576 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
5577 inc_val = XEXP (y, 1);
5578 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
5579 inc_val = XEXP (y, 0);
5583 if (GET_CODE (inc_val) == CONST_INT)
5585 if (HAVE_POST_INCREMENT
5586 && (INTVAL (inc_val) == size && offset == 0))
5587 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
5589 else if (HAVE_POST_DECREMENT
5590 && (INTVAL (inc_val) == -size && offset == 0))
5591 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
5593 else if (HAVE_PRE_INCREMENT
5594 && (INTVAL (inc_val) == size && offset == size))
5595 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
5597 else if (HAVE_PRE_DECREMENT
5598 && (INTVAL (inc_val) == -size && offset == -size))
5599 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
5601 else if (HAVE_POST_MODIFY_DISP && offset == 0)
5602 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
5603 gen_rtx_PLUS (Pmode,
5606 insn, x, incr, addr);
5608 else if (GET_CODE (inc_val) == REG
5609 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
5613 if (HAVE_POST_MODIFY_REG && offset == 0)
5614 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
5615 gen_rtx_PLUS (Pmode,
5618 insn, x, incr, addr);
5622 #endif /* AUTO_INC_DEC */
5625 mark_used_reg (pbi, reg, cond, insn)
5626 struct propagate_block_info *pbi;
5628 rtx cond ATTRIBUTE_UNUSED;
5631 unsigned int regno_first, regno_last, i;
5632 int some_was_live, some_was_dead, some_not_set;
5634 regno_last = regno_first = REGNO (reg);
5635 if (regno_first < FIRST_PSEUDO_REGISTER)
5636 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
5638 /* Find out if any of this register is live after this instruction. */
5639 some_was_live = some_was_dead = 0;
5640 for (i = regno_first; i <= regno_last; ++i)
5642 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
5643 some_was_live |= needed_regno;
5644 some_was_dead |= ! needed_regno;
5647 /* Find out if any of the register was set this insn. */
5649 for (i = regno_first; i <= regno_last; ++i)
5650 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
5652 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
5654 /* Record where each reg is used, so when the reg is set we know
5655 the next insn that uses it. */
5656 pbi->reg_next_use[regno_first] = insn;
5659 if (pbi->flags & PROP_REG_INFO)
5661 if (regno_first < FIRST_PSEUDO_REGISTER)
5663 /* If this is a register we are going to try to eliminate,
5664 don't mark it live here. If we are successful in
5665 eliminating it, it need not be live unless it is used for
5666 pseudos, in which case it will have been set live when it
5667 was allocated to the pseudos. If the register will not
5668 be eliminated, reload will set it live at that point.
5670 Otherwise, record that this function uses this register. */
5671 /* ??? The PPC backend tries to "eliminate" on the pic
5672 register to itself. This should be fixed. In the mean
5673 time, hack around it. */
5675 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
5676 && (regno_first == FRAME_POINTER_REGNUM
5677 || regno_first == ARG_POINTER_REGNUM)))
5678 for (i = regno_first; i <= regno_last; ++i)
5679 regs_ever_live[i] = 1;
5683 /* Keep track of which basic block each reg appears in. */
5685 register int blocknum = pbi->bb->index;
5686 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
5687 REG_BASIC_BLOCK (regno_first) = blocknum;
5688 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
5689 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
5691 /* Count (weighted) number of uses of each reg. */
5692 REG_FREQ (regno_first)
5693 += (optimize_size ? 1 : pbi->bb->loop_depth + 1);
5694 REG_N_REFS (regno_first)++;
5698 /* Record and count the insns in which a reg dies. If it is used in
5699 this insn and was dead below the insn then it dies in this insn.
5700 If it was set in this insn, we do not make a REG_DEAD note;
5701 likewise if we already made such a note. */
5702 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
5706 /* Check for the case where the register dying partially
5707 overlaps the register set by this insn. */
5708 if (regno_first != regno_last)
5709 for (i = regno_first; i <= regno_last; ++i)
5710 some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
5712 /* If none of the words in X is needed, make a REG_DEAD note.
5713 Otherwise, we must make partial REG_DEAD notes. */
5714 if (! some_was_live)
5716 if ((pbi->flags & PROP_DEATH_NOTES)
5717 && ! find_regno_note (insn, REG_DEAD, regno_first))
5719 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
5721 if (pbi->flags & PROP_REG_INFO)
5722 REG_N_DEATHS (regno_first)++;
5726 /* Don't make a REG_DEAD note for a part of a register
5727 that is set in the insn. */
5728 for (i = regno_first; i <= regno_last; ++i)
5729 if (! REGNO_REG_SET_P (pbi->reg_live, i)
5730 && ! dead_or_set_regno_p (insn, i))
5732 = alloc_EXPR_LIST (REG_DEAD,
5733 gen_rtx_REG (reg_raw_mode[i], i),
5738 /* Mark the register as being live. */
5739 for (i = regno_first; i <= regno_last; ++i)
5741 SET_REGNO_REG_SET (pbi->reg_live, i);
5743 #ifdef HAVE_conditional_execution
5744 /* If this is a conditional use, record that fact. If it is later
5745 conditionally set, we'll know to kill the register. */
5746 if (cond != NULL_RTX)
5748 splay_tree_node node;
5749 struct reg_cond_life_info *rcli;
5754 node = splay_tree_lookup (pbi->reg_cond_dead, i);
5757 /* The register was unconditionally live previously.
5758 No need to do anything. */
5762 /* The register was conditionally live previously.
5763 Subtract the new life cond from the old death cond. */
5764 rcli = (struct reg_cond_life_info *) node->value;
5765 ncond = rcli->condition;
5766 ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
5768 /* If the register is now unconditionally live,
5769 remove the entry in the splay_tree. */
5770 if (ncond == const0_rtx)
5771 splay_tree_remove (pbi->reg_cond_dead, i);
5774 rcli->condition = ncond;
5775 SET_REGNO_REG_SET (pbi->reg_cond_reg,
5776 REGNO (XEXP (cond, 0)));
5782 /* The register was not previously live at all. Record
5783 the condition under which it is still dead. */
5784 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
5785 rcli->condition = not_reg_cond (cond);
5786 rcli->stores = const0_rtx;
5787 rcli->orig_condition = const0_rtx;
5788 splay_tree_insert (pbi->reg_cond_dead, i,
5789 (splay_tree_value) rcli);
5791 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5794 else if (some_was_live)
5796 /* The register may have been conditionally live previously, but
5797 is now unconditionally live. Remove it from the conditionally
5798 dead list, so that a conditional set won't cause us to think
5800 splay_tree_remove (pbi->reg_cond_dead, i);
5806 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
5807 This is done assuming the registers needed from X are those that
5808 have 1-bits in PBI->REG_LIVE.
5810 INSN is the containing instruction. If INSN is dead, this function
5814 mark_used_regs (pbi, x, cond, insn)
5815 struct propagate_block_info *pbi;
5818 register RTX_CODE code;
5820 int flags = pbi->flags;
5823 code = GET_CODE (x);
5843 /* If we are clobbering a MEM, mark any registers inside the address
5845 if (GET_CODE (XEXP (x, 0)) == MEM)
5846 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
5850 /* Don't bother watching stores to mems if this is not the
5851 final pass. We'll not be deleting dead stores this round. */
5852 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
5854 /* Invalidate the data for the last MEM stored, but only if MEM is
5855 something that can be stored into. */
5856 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
5857 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
5858 /* Needn't clear the memory set list. */
5862 rtx temp = pbi->mem_set_list;
5863 rtx prev = NULL_RTX;
5868 next = XEXP (temp, 1);
5869 if (anti_dependence (XEXP (temp, 0), x))
5871 /* Splice temp out of the list. */
5873 XEXP (prev, 1) = next;
5875 pbi->mem_set_list = next;
5876 free_EXPR_LIST_node (temp);
5877 pbi->mem_set_list_len--;
5885 /* If the memory reference had embedded side effects (autoincrement
5886 address modes. Then we may need to kill some entries on the
5889 invalidate_mems_from_autoinc (pbi, insn);
5893 if (flags & PROP_AUTOINC)
5894 find_auto_inc (pbi, x, insn);
5899 #ifdef CLASS_CANNOT_CHANGE_MODE
5900 if (GET_CODE (SUBREG_REG (x)) == REG
5901 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
5902 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
5903 GET_MODE (SUBREG_REG (x))))
5904 REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
5907 /* While we're here, optimize this case. */
5909 if (GET_CODE (x) != REG)
5914 /* See a register other than being set => mark it as needed. */
5915 mark_used_reg (pbi, x, cond, insn);
5920 register rtx testreg = SET_DEST (x);
5923 /* If storing into MEM, don't show it as being used. But do
5924 show the address as being used. */
5925 if (GET_CODE (testreg) == MEM)
5928 if (flags & PROP_AUTOINC)
5929 find_auto_inc (pbi, testreg, insn);
5931 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
5932 mark_used_regs (pbi, SET_SRC (x), cond, insn);
5936 /* Storing in STRICT_LOW_PART is like storing in a reg
5937 in that this SET might be dead, so ignore it in TESTREG.
5938 but in some other ways it is like using the reg.
5940 Storing in a SUBREG or a bit field is like storing the entire
5941 register in that if the register's value is not used
5942 then this SET is not needed. */
5943 while (GET_CODE (testreg) == STRICT_LOW_PART
5944 || GET_CODE (testreg) == ZERO_EXTRACT
5945 || GET_CODE (testreg) == SIGN_EXTRACT
5946 || GET_CODE (testreg) == SUBREG)
5948 #ifdef CLASS_CANNOT_CHANGE_MODE
5949 if (GET_CODE (testreg) == SUBREG
5950 && GET_CODE (SUBREG_REG (testreg)) == REG
5951 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
5952 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
5953 GET_MODE (testreg)))
5954 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
5957 /* Modifying a single register in an alternate mode
5958 does not use any of the old value. But these other
5959 ways of storing in a register do use the old value. */
5960 if (GET_CODE (testreg) == SUBREG
5961 && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
5966 testreg = XEXP (testreg, 0);
5969 /* If this is a store into a register or group of registers,
5970 recursively scan the value being stored. */
5972 if ((GET_CODE (testreg) == PARALLEL
5973 && GET_MODE (testreg) == BLKmode)
5974 || (GET_CODE (testreg) == REG
5975 && (regno = REGNO (testreg),
5976 ! (regno == FRAME_POINTER_REGNUM
5977 && (! reload_completed || frame_pointer_needed)))
5978 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
5979 && ! (regno == HARD_FRAME_POINTER_REGNUM
5980 && (! reload_completed || frame_pointer_needed))
5982 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
5983 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
5988 mark_used_regs (pbi, SET_DEST (x), cond, insn);
5989 mark_used_regs (pbi, SET_SRC (x), cond, insn);
5996 case UNSPEC_VOLATILE:
6000 /* Traditional and volatile asm instructions must be considered to use
6001 and clobber all hard registers, all pseudo-registers and all of
6002 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
6004 Consider for instance a volatile asm that changes the fpu rounding
6005 mode. An insn should not be moved across this even if it only uses
6006 pseudo-regs because it might give an incorrectly rounded result.
6008 ?!? Unfortunately, marking all hard registers as live causes massive
6009 problems for the register allocator and marking all pseudos as live
6010 creates mountains of uninitialized variable warnings.
6012 So for now, just clear the memory set list and mark any regs
6013 we can find in ASM_OPERANDS as used. */
6014 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
6016 free_EXPR_LIST_list (&pbi->mem_set_list);
6017 pbi->mem_set_list_len = 0;
6020 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
6021 We can not just fall through here since then we would be confused
6022 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
6023 traditional asms unlike their normal usage. */
6024 if (code == ASM_OPERANDS)
6028 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
6029 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
6035 if (cond != NULL_RTX)
6038 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
6040 cond = COND_EXEC_TEST (x);
6041 x = COND_EXEC_CODE (x);
6045 /* We _do_not_ want to scan operands of phi nodes. Operands of
6046 a phi function are evaluated only when control reaches this
6047 block along a particular edge. Therefore, regs that appear
6048 as arguments to phi should not be added to the global live at
6056 /* Recursively scan the operands of this expression. */
6059 register const char *fmt = GET_RTX_FORMAT (code);
6062 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
6066 /* Tail recursive case: save a function call level. */
6072 mark_used_regs (pbi, XEXP (x, i), cond, insn);
6074 else if (fmt[i] == 'E')
6077 for (j = 0; j < XVECLEN (x, i); j++)
6078 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
6087 try_pre_increment_1 (pbi, insn)
6088 struct propagate_block_info *pbi;
6091 /* Find the next use of this reg. If in same basic block,
6092 make it do pre-increment or pre-decrement if appropriate. */
6093 rtx x = single_set (insn);
6094 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
6095 * INTVAL (XEXP (SET_SRC (x), 1)));
6096 int regno = REGNO (SET_DEST (x));
6097 rtx y = pbi->reg_next_use[regno];
6099 && SET_DEST (x) != stack_pointer_rtx
6100 && BLOCK_NUM (y) == BLOCK_NUM (insn)
6101 /* Don't do this if the reg dies, or gets set in y; a standard addressing
6102 mode would be better. */
6103 && ! dead_or_set_p (y, SET_DEST (x))
6104 && try_pre_increment (y, SET_DEST (x), amount))
6106 /* We have found a suitable auto-increment and already changed
6107 insn Y to do it. So flush this increment instruction. */
6108 propagate_block_delete_insn (pbi->bb, insn);
6110 /* Count a reference to this reg for the increment insn we are
6111 deleting. When a reg is incremented, spilling it is worse,
6112 so we want to make that less likely. */
6113 if (regno >= FIRST_PSEUDO_REGISTER)
6115 REG_FREQ (regno) += (optimize_size ? 1 : pbi->bb->loop_depth + 1);
6116 REG_N_SETS (regno)++;
6119 /* Flush any remembered memories depending on the value of
6120 the incremented register. */
6121 invalidate_mems_from_set (pbi, SET_DEST (x));
6128 /* Try to change INSN so that it does pre-increment or pre-decrement
6129 addressing on register REG in order to add AMOUNT to REG.
6130 AMOUNT is negative for pre-decrement.
6131 Returns 1 if the change could be made.
6132 This checks all about the validity of the result of modifying INSN. */
6135 try_pre_increment (insn, reg, amount)
6137 HOST_WIDE_INT amount;
6141 /* Nonzero if we can try to make a pre-increment or pre-decrement.
6142 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
6144 /* Nonzero if we can try to make a post-increment or post-decrement.
6145 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
6146 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
6147 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
6150 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
6153 /* From the sign of increment, see which possibilities are conceivable
6154 on this target machine. */
6155 if (HAVE_PRE_INCREMENT && amount > 0)
6157 if (HAVE_POST_INCREMENT && amount > 0)
6160 if (HAVE_PRE_DECREMENT && amount < 0)
6162 if (HAVE_POST_DECREMENT && amount < 0)
6165 if (! (pre_ok || post_ok))
6168 /* It is not safe to add a side effect to a jump insn
6169 because if the incremented register is spilled and must be reloaded
6170 there would be no way to store the incremented value back in memory. */
6172 if (GET_CODE (insn) == JUMP_INSN)
6177 use = find_use_as_address (PATTERN (insn), reg, 0);
6178 if (post_ok && (use == 0 || use == (rtx) 1))
6180 use = find_use_as_address (PATTERN (insn), reg, -amount);
6184 if (use == 0 || use == (rtx) 1)
6187 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
6190 /* See if this combination of instruction and addressing mode exists. */
6191 if (! validate_change (insn, &XEXP (use, 0),
6192 gen_rtx_fmt_e (amount > 0
6193 ? (do_post ? POST_INC : PRE_INC)
6194 : (do_post ? POST_DEC : PRE_DEC),
6198 /* Record that this insn now has an implicit side effect on X. */
6199 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
6203 #endif /* AUTO_INC_DEC */
6205 /* Find the place in the rtx X where REG is used as a memory address.
6206 Return the MEM rtx that so uses it.
6207 If PLUSCONST is nonzero, search instead for a memory address equivalent to
6208 (plus REG (const_int PLUSCONST)).
6210 If such an address does not appear, return 0.
6211 If REG appears more than once, or is used other than in such an address,
6215 find_use_as_address (x, reg, plusconst)
6218 HOST_WIDE_INT plusconst;
6220 enum rtx_code code = GET_CODE (x);
6221 const char *fmt = GET_RTX_FORMAT (code);
6223 register rtx value = 0;
6226 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
6229 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
6230 && XEXP (XEXP (x, 0), 0) == reg
6231 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
6232 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
6235 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
6237 /* If REG occurs inside a MEM used in a bit-field reference,
6238 that is unacceptable. */
6239 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
6240 return (rtx) (HOST_WIDE_INT) 1;
6244 return (rtx) (HOST_WIDE_INT) 1;
6246 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
6250 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
6254 return (rtx) (HOST_WIDE_INT) 1;
6256 else if (fmt[i] == 'E')
6259 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
6261 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
6265 return (rtx) (HOST_WIDE_INT) 1;
6273 /* Write information about registers and basic blocks into FILE.
6274 This is part of making a debugging dump. */
6277 dump_regset (r, outf)
6284 fputs (" (nil)", outf);
6288 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
6290 fprintf (outf, " %d", i);
6291 if (i < FIRST_PSEUDO_REGISTER)
6292 fprintf (outf, " [%s]",
6297 /* Print a human-reaable representation of R on the standard error
6298 stream. This function is designed to be used from within the
6305 dump_regset (r, stderr);
6306 putc ('\n', stderr);
6310 dump_flow_info (file)
6314 static const char * const reg_class_names[] = REG_CLASS_NAMES;
6316 fprintf (file, "%d registers.\n", max_regno);
6317 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
6320 enum reg_class class, altclass;
6321 fprintf (file, "\nRegister %d used %d times across %d insns",
6322 i, REG_N_REFS (i), REG_LIVE_LENGTH (i));
6323 if (REG_BASIC_BLOCK (i) >= 0)
6324 fprintf (file, " in block %d", REG_BASIC_BLOCK (i));
6326 fprintf (file, "; set %d time%s", REG_N_SETS (i),
6327 (REG_N_SETS (i) == 1) ? "" : "s");
6328 if (REG_USERVAR_P (regno_reg_rtx[i]))
6329 fprintf (file, "; user var");
6330 if (REG_N_DEATHS (i) != 1)
6331 fprintf (file, "; dies in %d places", REG_N_DEATHS (i));
6332 if (REG_N_CALLS_CROSSED (i) == 1)
6333 fprintf (file, "; crosses 1 call");
6334 else if (REG_N_CALLS_CROSSED (i))
6335 fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i));
6336 if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
6337 fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
6338 class = reg_preferred_class (i);
6339 altclass = reg_alternate_class (i);
6340 if (class != GENERAL_REGS || altclass != ALL_REGS)
6342 if (altclass == ALL_REGS || class == ALL_REGS)
6343 fprintf (file, "; pref %s", reg_class_names[(int) class]);
6344 else if (altclass == NO_REGS)
6345 fprintf (file, "; %s or none", reg_class_names[(int) class]);
6347 fprintf (file, "; pref %s, else %s",
6348 reg_class_names[(int) class],
6349 reg_class_names[(int) altclass]);
6351 if (REG_POINTER (regno_reg_rtx[i]))
6352 fprintf (file, "; pointer");
6353 fprintf (file, ".\n");
6356 fprintf (file, "\n%d basic blocks, %d edges.\n", n_basic_blocks, n_edges);
6357 for (i = 0; i < n_basic_blocks; i++)
6359 register basic_block bb = BASIC_BLOCK (i);
6362 fprintf (file, "\nBasic block %d: first insn %d, last %d, loop_depth %d, count ",
6363 i, INSN_UID (bb->head), INSN_UID (bb->end), bb->loop_depth);
6364 fprintf (file, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT) bb->count);
6365 fprintf (file, ", freq %i.\n", bb->frequency);
6367 fprintf (file, "Predecessors: ");
6368 for (e = bb->pred; e; e = e->pred_next)
6369 dump_edge_info (file, e, 0);
6371 fprintf (file, "\nSuccessors: ");
6372 for (e = bb->succ; e; e = e->succ_next)
6373 dump_edge_info (file, e, 1);
6375 fprintf (file, "\nRegisters live at start:");
6376 dump_regset (bb->global_live_at_start, file);
6378 fprintf (file, "\nRegisters live at end:");
6379 dump_regset (bb->global_live_at_end, file);
6390 dump_flow_info (stderr);
6394 dump_edge_info (file, e, do_succ)
6399 basic_block side = (do_succ ? e->dest : e->src);
6401 if (side == ENTRY_BLOCK_PTR)
6402 fputs (" ENTRY", file);
6403 else if (side == EXIT_BLOCK_PTR)
6404 fputs (" EXIT", file);
6406 fprintf (file, " %d", side->index);
6409 fprintf (file, " [%.1f%%] ", e->probability * 100.0 / REG_BR_PROB_BASE);
6413 fprintf (file, " count:");
6414 fprintf (file, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT) e->count);
6419 static const char * const bitnames[] = {
6420 "fallthru", "crit", "ab", "abcall", "eh", "fake"
6423 int i, flags = e->flags;
6427 for (i = 0; flags; i++)
6428 if (flags & (1 << i))
6434 if (i < (int) ARRAY_SIZE (bitnames))
6435 fputs (bitnames[i], file);
6437 fprintf (file, "%d", i);
6444 /* Print out one basic block with live information at start and end. */
6455 fprintf (outf, ";; Basic block %d, loop depth %d, count ",
6456 bb->index, bb->loop_depth, bb->count);
6457 fprintf (outf, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT) bb->count);
6460 fputs (";; Predecessors: ", outf);
6461 for (e = bb->pred; e; e = e->pred_next)
6462 dump_edge_info (outf, e, 0);
6465 fputs (";; Registers live at start:", outf);
6466 dump_regset (bb->global_live_at_start, outf);
6469 for (insn = bb->head, last = NEXT_INSN (bb->end);
6471 insn = NEXT_INSN (insn))
6472 print_rtl_single (outf, insn);
6474 fputs (";; Registers live at end:", outf);
6475 dump_regset (bb->global_live_at_end, outf);
6478 fputs (";; Successors: ", outf);
6479 for (e = bb->succ; e; e = e->succ_next)
6480 dump_edge_info (outf, e, 1);
6488 dump_bb (bb, stderr);
6495 dump_bb (BASIC_BLOCK (n), stderr);
6498 /* Like print_rtl, but also print out live information for the start of each
6502 print_rtl_with_bb (outf, rtx_first)
6506 register rtx tmp_rtx;
6509 fprintf (outf, "(nil)\n");
6513 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
6514 int max_uid = get_max_uid ();
6515 basic_block *start = (basic_block *)
6516 xcalloc (max_uid, sizeof (basic_block));
6517 basic_block *end = (basic_block *)
6518 xcalloc (max_uid, sizeof (basic_block));
6519 enum bb_state *in_bb_p = (enum bb_state *)
6520 xcalloc (max_uid, sizeof (enum bb_state));
6522 for (i = n_basic_blocks - 1; i >= 0; i--)
6524 basic_block bb = BASIC_BLOCK (i);
6527 start[INSN_UID (bb->head)] = bb;
6528 end[INSN_UID (bb->end)] = bb;
6529 for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x))
6531 enum bb_state state = IN_MULTIPLE_BB;
6532 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
6534 in_bb_p[INSN_UID (x)] = state;
6541 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
6546 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
6548 fprintf (outf, ";; Start of basic block %d, registers live:",
6550 dump_regset (bb->global_live_at_start, outf);
6554 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
6555 && GET_CODE (tmp_rtx) != NOTE
6556 && GET_CODE (tmp_rtx) != BARRIER)
6557 fprintf (outf, ";; Insn is not within a basic block\n");
6558 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
6559 fprintf (outf, ";; Insn is in multiple basic blocks\n");
6561 did_output = print_rtl_single (outf, tmp_rtx);
6563 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
6565 fprintf (outf, ";; End of basic block %d, registers live:\n",
6567 dump_regset (bb->global_live_at_end, outf);
6580 if (current_function_epilogue_delay_list != 0)
6582 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
6583 for (tmp_rtx = current_function_epilogue_delay_list; tmp_rtx != 0;
6584 tmp_rtx = XEXP (tmp_rtx, 1))
6585 print_rtl_single (outf, XEXP (tmp_rtx, 0));
6589 /* Dump the rtl into the current debugging dump file, then abort. */
6592 print_rtl_and_abort_fcn (file, line, function)
6595 const char *function;
6599 print_rtl_with_bb (rtl_dump_file, get_insns ());
6600 fclose (rtl_dump_file);
6603 fancy_abort (file, line, function);
6606 /* Recompute register set/reference counts immediately prior to register
6609 This avoids problems with set/reference counts changing to/from values
6610 which have special meanings to the register allocators.
6612 Additionally, the reference counts are the primary component used by the
6613 register allocators to prioritize pseudos for allocation to hard regs.
6614 More accurate reference counts generally lead to better register allocation.
6616 F is the first insn to be scanned.
6618 LOOP_STEP denotes how much loop_depth should be incremented per
6619 loop nesting level in order to increase the ref count more for
6620 references in a loop.
6622 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
6623 possibly other information which is used by the register allocators. */
6626 recompute_reg_usage (f, loop_step)
6627 rtx f ATTRIBUTE_UNUSED;
6628 int loop_step ATTRIBUTE_UNUSED;
6630 allocate_reg_life_data ();
6631 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
6634 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
6635 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
6636 of the number of registers that died. */
6639 count_or_remove_death_notes (blocks, kill)
6645 for (i = n_basic_blocks - 1; i >= 0; --i)
6650 if (blocks && ! TEST_BIT (blocks, i))
6653 bb = BASIC_BLOCK (i);
6655 for (insn = bb->head;; insn = NEXT_INSN (insn))
6659 rtx *pprev = ®_NOTES (insn);
6664 switch (REG_NOTE_KIND (link))
6667 if (GET_CODE (XEXP (link, 0)) == REG)
6669 rtx reg = XEXP (link, 0);
6672 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
6675 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
6683 rtx next = XEXP (link, 1);
6684 free_EXPR_LIST_node (link);
6685 *pprev = link = next;
6691 pprev = &XEXP (link, 1);
6698 if (insn == bb->end)
6707 /* Update insns block within BB. */
6710 update_bb_for_insn (bb)
6715 if (! basic_block_for_insn)
6718 for (insn = bb->head; ; insn = NEXT_INSN (insn))
6720 set_block_for_insn (insn, bb);
6722 if (insn == bb->end)
6728 /* Record INSN's block as BB. */
6731 set_block_for_insn (insn, bb)
6735 size_t uid = INSN_UID (insn);
6736 if (uid >= basic_block_for_insn->num_elements)
6740 /* Add one-eighth the size so we don't keep calling xrealloc. */
6741 new_size = uid + (uid + 7) / 8;
6743 VARRAY_GROW (basic_block_for_insn, new_size);
6745 VARRAY_BB (basic_block_for_insn, uid) = bb;
6748 /* When a new insn has been inserted into an existing block, it will
6749 sometimes emit more than a single insn. This routine will set the
6750 block number for the specified insn, and look backwards in the insn
6751 chain to see if there are any other uninitialized insns immediately
6752 previous to this one, and set the block number for them too. */
6755 set_block_for_new_insns (insn, bb)
6759 set_block_for_insn (insn, bb);
6761 /* Scan the previous instructions setting the block number until we find
6762 an instruction that has the block number set, or we find a note
6764 for (insn = PREV_INSN (insn); insn != NULL_RTX; insn = PREV_INSN (insn))
6766 if (GET_CODE (insn) == NOTE)
6768 if (INSN_UID (insn) >= basic_block_for_insn->num_elements
6769 || BLOCK_FOR_INSN (insn) == 0)
6770 set_block_for_insn (insn, bb);
6776 /* Verify the CFG consistency. This function check some CFG invariants and
6777 aborts when something is wrong. Hope that this function will help to
6778 convert many optimization passes to preserve CFG consistent.
6780 Currently it does following checks:
6782 - test head/end pointers
6783 - overlapping of basic blocks
6784 - edge list corectness
6785 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
6786 - tails of basic blocks (ensure that boundary is necesary)
6787 - scans body of the basic block for JUMP_INSN, CODE_LABEL
6788 and NOTE_INSN_BASIC_BLOCK
6789 - check that all insns are in the basic blocks
6790 (except the switch handling code, barriers and notes)
6791 - check that all returns are followed by barriers
6793 In future it can be extended check a lot of other stuff as well
6794 (reachability of basic blocks, life information, etc. etc.). */
6799 const int max_uid = get_max_uid ();
6800 const rtx rtx_first = get_insns ();
6801 rtx last_head = get_last_insn ();
6802 basic_block *bb_info;
6804 int i, last_bb_num_seen, num_bb_notes, err = 0;
6806 bb_info = (basic_block *) xcalloc (max_uid, sizeof (basic_block));
6808 for (i = n_basic_blocks - 1; i >= 0; i--)
6810 basic_block bb = BASIC_BLOCK (i);
6811 rtx head = bb->head;
6814 /* Verify the end of the basic block is in the INSN chain. */
6815 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
6820 error ("End insn %d for block %d not found in the insn stream.",
6821 INSN_UID (end), bb->index);
6825 /* Work backwards from the end to the head of the basic block
6826 to verify the head is in the RTL chain. */
6827 for (; x != NULL_RTX; x = PREV_INSN (x))
6829 /* While walking over the insn chain, verify insns appear
6830 in only one basic block and initialize the BB_INFO array
6831 used by other passes. */
6832 if (bb_info[INSN_UID (x)] != NULL)
6834 error ("Insn %d is in multiple basic blocks (%d and %d)",
6835 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
6838 bb_info[INSN_UID (x)] = bb;
6845 error ("Head insn %d for block %d not found in the insn stream.",
6846 INSN_UID (head), bb->index);
6853 /* Now check the basic blocks (boundaries etc.) */
6854 for (i = n_basic_blocks - 1; i >= 0; i--)
6856 basic_block bb = BASIC_BLOCK (i);
6857 /* Check corectness of edge lists */
6866 "verify_flow_info: Basic block %d succ edge is corrupted\n",
6868 fprintf (stderr, "Predecessor: ");
6869 dump_edge_info (stderr, e, 0);
6870 fprintf (stderr, "\nSuccessor: ");
6871 dump_edge_info (stderr, e, 1);
6875 if (e->dest != EXIT_BLOCK_PTR)
6877 edge e2 = e->dest->pred;
6878 while (e2 && e2 != e)
6882 error ("Basic block %i edge lists are corrupted", bb->index);
6894 error ("Basic block %d pred edge is corrupted", bb->index);
6895 fputs ("Predecessor: ", stderr);
6896 dump_edge_info (stderr, e, 0);
6897 fputs ("\nSuccessor: ", stderr);
6898 dump_edge_info (stderr, e, 1);
6899 fputc ('\n', stderr);
6902 if (e->src != ENTRY_BLOCK_PTR)
6904 edge e2 = e->src->succ;
6905 while (e2 && e2 != e)
6909 error ("Basic block %i edge lists are corrupted", bb->index);
6916 /* OK pointers are correct. Now check the header of basic
6917 block. It ought to contain optional CODE_LABEL followed
6918 by NOTE_BASIC_BLOCK. */
6920 if (GET_CODE (x) == CODE_LABEL)
6924 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
6930 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
6932 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d\n",
6939 /* Do checks for empty blocks here */
6946 if (NOTE_INSN_BASIC_BLOCK_P (x))
6948 error ("NOTE_INSN_BASIC_BLOCK %d in the middle of basic block %d",
6949 INSN_UID (x), bb->index);
6956 if (GET_CODE (x) == JUMP_INSN
6957 || GET_CODE (x) == CODE_LABEL
6958 || GET_CODE (x) == BARRIER)
6960 error ("In basic block %d:", bb->index);
6961 fatal_insn ("Flow control insn inside a basic block", x);
6969 last_bb_num_seen = -1;
6974 if (NOTE_INSN_BASIC_BLOCK_P (x))
6976 basic_block bb = NOTE_BASIC_BLOCK (x);
6978 if (bb->index != last_bb_num_seen + 1)
6979 /* Basic blocks not numbered consecutively. */
6982 last_bb_num_seen = bb->index;
6985 if (!bb_info[INSN_UID (x)])
6987 switch (GET_CODE (x))
6994 /* An addr_vec is placed outside any block block. */
6996 && GET_CODE (NEXT_INSN (x)) == JUMP_INSN
6997 && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
6998 || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
7003 /* But in any case, non-deletable labels can appear anywhere. */
7007 fatal_insn ("Insn outside basic block", x);
7012 && GET_CODE (x) == JUMP_INSN
7013 && returnjump_p (x) && ! condjump_p (x)
7014 && ! (NEXT_INSN (x) && GET_CODE (NEXT_INSN (x)) == BARRIER))
7015 fatal_insn ("Return not followed by barrier", x);
7020 if (num_bb_notes != n_basic_blocks)
7022 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
7023 num_bb_notes, n_basic_blocks);
7032 /* Functions to access an edge list with a vector representation.
7033 Enough data is kept such that given an index number, the
7034 pred and succ that edge represents can be determined, or
7035 given a pred and a succ, its index number can be returned.
7036 This allows algorithms which consume a lot of memory to
7037 represent the normally full matrix of edge (pred,succ) with a
7038 single indexed vector, edge (EDGE_INDEX (pred, succ)), with no
7039 wasted space in the client code due to sparse flow graphs. */
7041 /* This functions initializes the edge list. Basically the entire
7042 flowgraph is processed, and all edges are assigned a number,
7043 and the data structure is filled in. */
7048 struct edge_list *elist;
7054 block_count = n_basic_blocks + 2; /* Include the entry and exit blocks. */
7058 /* Determine the number of edges in the flow graph by counting successor
7059 edges on each basic block. */
7060 for (x = 0; x < n_basic_blocks; x++)
7062 basic_block bb = BASIC_BLOCK (x);
7064 for (e = bb->succ; e; e = e->succ_next)
7067 /* Don't forget successors of the entry block. */
7068 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
7071 elist = (struct edge_list *) xmalloc (sizeof (struct edge_list));
7072 elist->num_blocks = block_count;
7073 elist->num_edges = num_edges;
7074 elist->index_to_edge = (edge *) xmalloc (sizeof (edge) * num_edges);
7078 /* Follow successors of the entry block, and register these edges. */
7079 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
7081 elist->index_to_edge[num_edges] = e;
7085 for (x = 0; x < n_basic_blocks; x++)
7087 basic_block bb = BASIC_BLOCK (x);
7089 /* Follow all successors of blocks, and register these edges. */
7090 for (e = bb->succ; e; e = e->succ_next)
7092 elist->index_to_edge[num_edges] = e;
7099 /* This function free's memory associated with an edge list. */
7102 free_edge_list (elist)
7103 struct edge_list *elist;
7107 free (elist->index_to_edge);
7112 /* This function provides debug output showing an edge list. */
7115 print_edge_list (f, elist)
7117 struct edge_list *elist;
7120 fprintf (f, "Compressed edge list, %d BBs + entry & exit, and %d edges\n",
7121 elist->num_blocks - 2, elist->num_edges);
7123 for (x = 0; x < elist->num_edges; x++)
7125 fprintf (f, " %-4d - edge(", x);
7126 if (INDEX_EDGE_PRED_BB (elist, x) == ENTRY_BLOCK_PTR)
7127 fprintf (f, "entry,");
7129 fprintf (f, "%d,", INDEX_EDGE_PRED_BB (elist, x)->index);
7131 if (INDEX_EDGE_SUCC_BB (elist, x) == EXIT_BLOCK_PTR)
7132 fprintf (f, "exit)\n");
7134 fprintf (f, "%d)\n", INDEX_EDGE_SUCC_BB (elist, x)->index);
7138 /* This function provides an internal consistency check of an edge list,
7139 verifying that all edges are present, and that there are no
7143 verify_edge_list (f, elist)
7145 struct edge_list *elist;
7147 int x, pred, succ, index;
7150 for (x = 0; x < n_basic_blocks; x++)
7152 basic_block bb = BASIC_BLOCK (x);
7154 for (e = bb->succ; e; e = e->succ_next)
7156 pred = e->src->index;
7157 succ = e->dest->index;
7158 index = EDGE_INDEX (elist, e->src, e->dest);
7159 if (index == EDGE_INDEX_NO_EDGE)
7161 fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
7164 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
7165 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
7166 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
7167 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
7168 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
7169 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
7172 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
7174 pred = e->src->index;
7175 succ = e->dest->index;
7176 index = EDGE_INDEX (elist, e->src, e->dest);
7177 if (index == EDGE_INDEX_NO_EDGE)
7179 fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
7182 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
7183 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
7184 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
7185 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
7186 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
7187 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
7189 /* We've verified that all the edges are in the list, no lets make sure
7190 there are no spurious edges in the list. */
7192 for (pred = 0; pred < n_basic_blocks; pred++)
7193 for (succ = 0; succ < n_basic_blocks; succ++)
7195 basic_block p = BASIC_BLOCK (pred);
7196 basic_block s = BASIC_BLOCK (succ);
7200 for (e = p->succ; e; e = e->succ_next)
7206 for (e = s->pred; e; e = e->pred_next)
7212 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
7213 == EDGE_INDEX_NO_EDGE && found_edge != 0)
7214 fprintf (f, "*** Edge (%d, %d) appears to not have an index\n",
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) has index %d, but there is no edge\n",
7219 pred, succ, EDGE_INDEX (elist, BASIC_BLOCK (pred),
7220 BASIC_BLOCK (succ)));
7222 for (succ = 0; succ < n_basic_blocks; succ++)
7224 basic_block p = ENTRY_BLOCK_PTR;
7225 basic_block s = BASIC_BLOCK (succ);
7229 for (e = p->succ; e; e = e->succ_next)
7235 for (e = s->pred; e; e = e->pred_next)
7241 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
7242 == EDGE_INDEX_NO_EDGE && found_edge != 0)
7243 fprintf (f, "*** Edge (entry, %d) appears to not have an index\n",
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) has index %d, but no edge exists\n",
7248 succ, EDGE_INDEX (elist, ENTRY_BLOCK_PTR,
7249 BASIC_BLOCK (succ)));
7251 for (pred = 0; pred < n_basic_blocks; pred++)
7253 basic_block p = BASIC_BLOCK (pred);
7254 basic_block s = EXIT_BLOCK_PTR;
7258 for (e = p->succ; e; e = e->succ_next)
7264 for (e = s->pred; e; e = e->pred_next)
7270 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
7271 == EDGE_INDEX_NO_EDGE && found_edge != 0)
7272 fprintf (f, "*** Edge (%d, exit) appears to not have an index\n",
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) has index %d, but no edge exists\n",
7277 pred, EDGE_INDEX (elist, BASIC_BLOCK (pred),
7282 /* This routine will determine what, if any, edge there is between
7283 a specified predecessor and successor. */
7286 find_edge_index (edge_list, pred, succ)
7287 struct edge_list *edge_list;
7288 basic_block pred, succ;
7291 for (x = 0; x < NUM_EDGES (edge_list); x++)
7293 if (INDEX_EDGE_PRED_BB (edge_list, x) == pred
7294 && INDEX_EDGE_SUCC_BB (edge_list, x) == succ)
7297 return (EDGE_INDEX_NO_EDGE);
7300 /* This function will remove an edge from the flow graph. */
7306 edge last_pred = NULL;
7307 edge last_succ = NULL;
7309 basic_block src, dest;
7312 for (tmp = src->succ; tmp && tmp != e; tmp = tmp->succ_next)
7318 last_succ->succ_next = e->succ_next;
7320 src->succ = e->succ_next;
7322 for (tmp = dest->pred; tmp && tmp != e; tmp = tmp->pred_next)
7328 last_pred->pred_next = e->pred_next;
7330 dest->pred = e->pred_next;
7336 /* This routine will remove any fake successor edges for a basic block.
7337 When the edge is removed, it is also removed from whatever predecessor
7341 remove_fake_successors (bb)
7345 for (e = bb->succ; e;)
7349 if ((tmp->flags & EDGE_FAKE) == EDGE_FAKE)
7354 /* This routine will remove all fake edges from the flow graph. If
7355 we remove all fake successors, it will automatically remove all
7356 fake predecessors. */
7359 remove_fake_edges ()
7363 for (x = 0; x < n_basic_blocks; x++)
7364 remove_fake_successors (BASIC_BLOCK (x));
7366 /* We've handled all successors except the entry block's. */
7367 remove_fake_successors (ENTRY_BLOCK_PTR);
7370 /* This function will add a fake edge between any block which has no
7371 successors, and the exit block. Some data flow equations require these
7375 add_noreturn_fake_exit_edges ()
7379 for (x = 0; x < n_basic_blocks; x++)
7380 if (BASIC_BLOCK (x)->succ == NULL)
7381 make_edge (NULL, BASIC_BLOCK (x), EXIT_BLOCK_PTR, EDGE_FAKE);
7384 /* This function adds a fake edge between any infinite loops to the
7385 exit block. Some optimizations require a path from each node to
7388 See also Morgan, Figure 3.10, pp. 82-83.
7390 The current implementation is ugly, not attempting to minimize the
7391 number of inserted fake edges. To reduce the number of fake edges
7392 to insert, add fake edges from _innermost_ loops containing only
7393 nodes not reachable from the exit block. */
7396 connect_infinite_loops_to_exit ()
7398 basic_block unvisited_block;
7400 /* Perform depth-first search in the reverse graph to find nodes
7401 reachable from the exit block. */
7402 struct depth_first_search_dsS dfs_ds;
7404 flow_dfs_compute_reverse_init (&dfs_ds);
7405 flow_dfs_compute_reverse_add_bb (&dfs_ds, EXIT_BLOCK_PTR);
7407 /* Repeatedly add fake edges, updating the unreachable nodes. */
7410 unvisited_block = flow_dfs_compute_reverse_execute (&dfs_ds);
7411 if (!unvisited_block)
7413 make_edge (NULL, unvisited_block, EXIT_BLOCK_PTR, EDGE_FAKE);
7414 flow_dfs_compute_reverse_add_bb (&dfs_ds, unvisited_block);
7417 flow_dfs_compute_reverse_finish (&dfs_ds);
7422 /* Redirect an edge's successor from one block to another. */
7425 redirect_edge_succ (e, new_succ)
7427 basic_block new_succ;
7431 /* Disconnect the edge from the old successor block. */
7432 for (pe = &e->dest->pred; *pe != e; pe = &(*pe)->pred_next)
7434 *pe = (*pe)->pred_next;
7436 /* Reconnect the edge to the new successor block. */
7437 e->pred_next = new_succ->pred;
7442 /* Redirect an edge's predecessor from one block to another. */
7445 redirect_edge_pred (e, new_pred)
7447 basic_block new_pred;
7451 /* Disconnect the edge from the old predecessor block. */
7452 for (pe = &e->src->succ; *pe != e; pe = &(*pe)->succ_next)
7454 *pe = (*pe)->succ_next;
7456 /* Reconnect the edge to the new predecessor block. */
7457 e->succ_next = new_pred->succ;
7462 /* Dump the list of basic blocks in the bitmap NODES. */
7465 flow_nodes_print (str, nodes, file)
7467 const sbitmap nodes;
7475 fprintf (file, "%s { ", str);
7476 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {fprintf (file, "%d ", node);});
7477 fputs ("}\n", file);
7481 /* Dump the list of edges in the array EDGE_LIST. */
7484 flow_edge_list_print (str, edge_list, num_edges, file)
7486 const edge *edge_list;
7495 fprintf (file, "%s { ", str);
7496 for (i = 0; i < num_edges; i++)
7497 fprintf (file, "%d->%d ", edge_list[i]->src->index,
7498 edge_list[i]->dest->index);
7499 fputs ("}\n", file);
7503 /* Dump loop related CFG information. */
7506 flow_loops_cfg_dump (loops, file)
7507 const struct loops *loops;
7512 if (! loops->num || ! file || ! loops->cfg.dom)
7515 for (i = 0; i < n_basic_blocks; i++)
7519 fprintf (file, ";; %d succs { ", i);
7520 for (succ = BASIC_BLOCK (i)->succ; succ; succ = succ->succ_next)
7521 fprintf (file, "%d ", succ->dest->index);
7522 flow_nodes_print ("} dom", loops->cfg.dom[i], file);
7525 /* Dump the DFS node order. */
7526 if (loops->cfg.dfs_order)
7528 fputs (";; DFS order: ", file);
7529 for (i = 0; i < n_basic_blocks; i++)
7530 fprintf (file, "%d ", loops->cfg.dfs_order[i]);
7533 /* Dump the reverse completion node order. */
7534 if (loops->cfg.rc_order)
7536 fputs (";; RC order: ", file);
7537 for (i = 0; i < n_basic_blocks; i++)
7538 fprintf (file, "%d ", loops->cfg.rc_order[i]);
7543 /* Return non-zero if the nodes of LOOP are a subset of OUTER. */
7546 flow_loop_nested_p (outer, loop)
7550 return sbitmap_a_subset_b_p (loop->nodes, outer->nodes);
7554 /* Dump the loop information specified by LOOP to the stream FILE
7555 using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
7557 flow_loop_dump (loop, file, loop_dump_aux, verbose)
7558 const struct loop *loop;
7560 void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
7563 if (! loop || ! loop->header)
7566 fprintf (file, ";;\n;; Loop %d (%d to %d):%s%s\n",
7567 loop->num, INSN_UID (loop->first->head),
7568 INSN_UID (loop->last->end),
7569 loop->shared ? " shared" : "",
7570 loop->invalid ? " invalid" : "");
7571 fprintf (file, ";; header %d, latch %d, pre-header %d, first %d, last %d\n",
7572 loop->header->index, loop->latch->index,
7573 loop->pre_header ? loop->pre_header->index : -1,
7574 loop->first->index, loop->last->index);
7575 fprintf (file, ";; depth %d, level %d, outer %ld\n",
7576 loop->depth, loop->level,
7577 (long) (loop->outer ? loop->outer->num : -1));
7579 if (loop->pre_header_edges)
7580 flow_edge_list_print (";; pre-header edges", loop->pre_header_edges,
7581 loop->num_pre_header_edges, file);
7582 flow_edge_list_print (";; entry edges", loop->entry_edges,
7583 loop->num_entries, file);
7584 fprintf (file, ";; %d", loop->num_nodes);
7585 flow_nodes_print (" nodes", loop->nodes, file);
7586 flow_edge_list_print (";; exit edges", loop->exit_edges,
7587 loop->num_exits, file);
7588 if (loop->exits_doms)
7589 flow_nodes_print (";; exit doms", loop->exits_doms, file);
7591 loop_dump_aux (loop, file, verbose);
7595 /* Dump the loop information specified by LOOPS to the stream FILE,
7596 using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
7598 flow_loops_dump (loops, file, loop_dump_aux, verbose)
7599 const struct loops *loops;
7601 void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
7607 num_loops = loops->num;
7608 if (! num_loops || ! file)
7611 fprintf (file, ";; %d loops found, %d levels\n",
7612 num_loops, loops->levels);
7614 for (i = 0; i < num_loops; i++)
7616 struct loop *loop = &loops->array[i];
7618 flow_loop_dump (loop, file, loop_dump_aux, verbose);
7624 for (j = 0; j < i; j++)
7626 struct loop *oloop = &loops->array[j];
7628 if (loop->header == oloop->header)
7633 smaller = loop->num_nodes < oloop->num_nodes;
7635 /* If the union of LOOP and OLOOP is different than
7636 the larger of LOOP and OLOOP then LOOP and OLOOP
7637 must be disjoint. */
7638 disjoint = ! flow_loop_nested_p (smaller ? loop : oloop,
7639 smaller ? oloop : loop);
7641 ";; loop header %d shared by loops %d, %d %s\n",
7642 loop->header->index, i, j,
7643 disjoint ? "disjoint" : "nested");
7650 flow_loops_cfg_dump (loops, file);
7654 /* Free all the memory allocated for LOOPS. */
7657 flow_loops_free (loops)
7658 struct loops *loops;
7667 /* Free the loop descriptors. */
7668 for (i = 0; i < loops->num; i++)
7670 struct loop *loop = &loops->array[i];
7672 if (loop->pre_header_edges)
7673 free (loop->pre_header_edges);
7675 sbitmap_free (loop->nodes);
7676 if (loop->entry_edges)
7677 free (loop->entry_edges);
7678 if (loop->exit_edges)
7679 free (loop->exit_edges);
7680 if (loop->exits_doms)
7681 sbitmap_free (loop->exits_doms);
7683 free (loops->array);
7684 loops->array = NULL;
7687 sbitmap_vector_free (loops->cfg.dom);
7688 if (loops->cfg.dfs_order)
7689 free (loops->cfg.dfs_order);
7691 if (loops->shared_headers)
7692 sbitmap_free (loops->shared_headers);
7697 /* Find the entry edges into the loop with header HEADER and nodes
7698 NODES and store in ENTRY_EDGES array. Return the number of entry
7699 edges from the loop. */
7702 flow_loop_entry_edges_find (header, nodes, entry_edges)
7704 const sbitmap nodes;
7710 *entry_edges = NULL;
7713 for (e = header->pred; e; e = e->pred_next)
7715 basic_block src = e->src;
7717 if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
7724 *entry_edges = (edge *) xmalloc (num_entries * sizeof (edge *));
7727 for (e = header->pred; e; e = e->pred_next)
7729 basic_block src = e->src;
7731 if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
7732 (*entry_edges)[num_entries++] = e;
7739 /* Find the exit edges from the loop using the bitmap of loop nodes
7740 NODES and store in EXIT_EDGES array. Return the number of
7741 exit edges from the loop. */
7744 flow_loop_exit_edges_find (nodes, exit_edges)
7745 const sbitmap nodes;
7754 /* Check all nodes within the loop to see if there are any
7755 successors not in the loop. Note that a node may have multiple
7756 exiting edges ????? A node can have one jumping edge and one fallthru
7757 edge so only one of these can exit the loop. */
7759 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
7760 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
7762 basic_block dest = e->dest;
7764 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
7772 *exit_edges = (edge *) xmalloc (num_exits * sizeof (edge *));
7774 /* Store all exiting edges into an array. */
7776 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
7777 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
7779 basic_block dest = e->dest;
7781 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
7782 (*exit_edges)[num_exits++] = e;
7790 /* Find the nodes contained within the loop with header HEADER and
7791 latch LATCH and store in NODES. Return the number of nodes within
7795 flow_loop_nodes_find (header, latch, nodes)
7804 stack = (basic_block *) xmalloc (n_basic_blocks * sizeof (basic_block));
7807 /* Start with only the loop header in the set of loop nodes. */
7808 sbitmap_zero (nodes);
7809 SET_BIT (nodes, header->index);
7811 header->loop_depth++;
7813 /* Push the loop latch on to the stack. */
7814 if (! TEST_BIT (nodes, latch->index))
7816 SET_BIT (nodes, latch->index);
7817 latch->loop_depth++;
7819 stack[sp++] = latch;
7828 for (e = node->pred; e; e = e->pred_next)
7830 basic_block ancestor = e->src;
7832 /* If each ancestor not marked as part of loop, add to set of
7833 loop nodes and push on to stack. */
7834 if (ancestor != ENTRY_BLOCK_PTR
7835 && ! TEST_BIT (nodes, ancestor->index))
7837 SET_BIT (nodes, ancestor->index);
7838 ancestor->loop_depth++;
7840 stack[sp++] = ancestor;
7848 /* Compute the depth first search order and store in the array
7849 DFS_ORDER if non-zero, marking the nodes visited in VISITED. If
7850 RC_ORDER is non-zero, return the reverse completion number for each
7851 node. Returns the number of nodes visited. A depth first search
7852 tries to get as far away from the starting point as quickly as
7856 flow_depth_first_order_compute (dfs_order, rc_order)
7863 int rcnum = n_basic_blocks - 1;
7866 /* Allocate stack for back-tracking up CFG. */
7867 stack = (edge *) xmalloc ((n_basic_blocks + 1) * sizeof (edge));
7870 /* Allocate bitmap to track nodes that have been visited. */
7871 visited = sbitmap_alloc (n_basic_blocks);
7873 /* None of the nodes in the CFG have been visited yet. */
7874 sbitmap_zero (visited);
7876 /* Push the first edge on to the stack. */
7877 stack[sp++] = ENTRY_BLOCK_PTR->succ;
7885 /* Look at the edge on the top of the stack. */
7890 /* Check if the edge destination has been visited yet. */
7891 if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index))
7893 /* Mark that we have visited the destination. */
7894 SET_BIT (visited, dest->index);
7897 dfs_order[dfsnum++] = dest->index;
7901 /* Since the DEST node has been visited for the first
7902 time, check its successors. */
7903 stack[sp++] = dest->succ;
7907 /* There are no successors for the DEST node so assign
7908 its reverse completion number. */
7910 rc_order[rcnum--] = dest->index;
7915 if (! e->succ_next && src != ENTRY_BLOCK_PTR)
7917 /* There are no more successors for the SRC node
7918 so assign its reverse completion number. */
7920 rc_order[rcnum--] = src->index;
7924 stack[sp - 1] = e->succ_next;
7931 sbitmap_free (visited);
7933 /* The number of nodes visited should not be greater than
7935 if (dfsnum > n_basic_blocks)
7938 /* There are some nodes left in the CFG that are unreachable. */
7939 if (dfsnum < n_basic_blocks)
7944 /* Compute the depth first search order on the _reverse_ graph and
7945 store in the array DFS_ORDER, marking the nodes visited in VISITED.
7946 Returns the number of nodes visited.
7948 The computation is split into three pieces:
7950 flow_dfs_compute_reverse_init () creates the necessary data
7953 flow_dfs_compute_reverse_add_bb () adds a basic block to the data
7954 structures. The block will start the search.
7956 flow_dfs_compute_reverse_execute () continues (or starts) the
7957 search using the block on the top of the stack, stopping when the
7960 flow_dfs_compute_reverse_finish () destroys the necessary data
7963 Thus, the user will probably call ..._init(), call ..._add_bb() to
7964 add a beginning basic block to the stack, call ..._execute(),
7965 possibly add another bb to the stack and again call ..._execute(),
7966 ..., and finally call _finish(). */
7968 /* Initialize the data structures used for depth-first search on the
7969 reverse graph. If INITIALIZE_STACK is nonzero, the exit block is
7970 added to the basic block stack. DATA is the current depth-first
7971 search context. If INITIALIZE_STACK is non-zero, there is an
7972 element on the stack. */
7975 flow_dfs_compute_reverse_init (data)
7976 depth_first_search_ds data;
7978 /* Allocate stack for back-tracking up CFG. */
7980 (basic_block *) xmalloc ((n_basic_blocks - (INVALID_BLOCK + 1))
7981 * sizeof (basic_block));
7984 /* Allocate bitmap to track nodes that have been visited. */
7985 data->visited_blocks = sbitmap_alloc (n_basic_blocks - (INVALID_BLOCK + 1));
7987 /* None of the nodes in the CFG have been visited yet. */
7988 sbitmap_zero (data->visited_blocks);
7993 /* Add the specified basic block to the top of the dfs data
7994 structures. When the search continues, it will start at the
7998 flow_dfs_compute_reverse_add_bb (data, bb)
7999 depth_first_search_ds data;
8002 data->stack[data->sp++] = bb;
8006 /* Continue the depth-first search through the reverse graph starting
8007 with the block at the stack's top and ending when the stack is
8008 empty. Visited nodes are marked. Returns an unvisited basic
8009 block, or NULL if there is none available. */
8012 flow_dfs_compute_reverse_execute (data)
8013 depth_first_search_ds data;
8019 while (data->sp > 0)
8021 bb = data->stack[--data->sp];
8023 /* Mark that we have visited this node. */
8024 if (!TEST_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1)))
8026 SET_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1));
8028 /* Perform depth-first search on adjacent vertices. */
8029 for (e = bb->pred; e; e = e->pred_next)
8030 flow_dfs_compute_reverse_add_bb (data, e->src);
8034 /* Determine if there are unvisited basic blocks. */
8035 for (i = n_basic_blocks - (INVALID_BLOCK + 1); --i >= 0;)
8036 if (!TEST_BIT (data->visited_blocks, i))
8037 return BASIC_BLOCK (i + (INVALID_BLOCK + 1));
8041 /* Destroy the data structures needed for depth-first search on the
8045 flow_dfs_compute_reverse_finish (data)
8046 depth_first_search_ds data;
8049 sbitmap_free (data->visited_blocks);
8054 /* Find the root node of the loop pre-header extended basic block and
8055 the edges along the trace from the root node to the loop header. */
8058 flow_loop_pre_header_scan (loop)
8064 loop->num_pre_header_edges = 0;
8066 if (loop->num_entries != 1)
8069 ebb = loop->entry_edges[0]->src;
8071 if (ebb != ENTRY_BLOCK_PTR)
8075 /* Count number of edges along trace from loop header to
8076 root of pre-header extended basic block. Usually this is
8077 only one or two edges. */
8079 while (ebb->pred->src != ENTRY_BLOCK_PTR && ! ebb->pred->pred_next)
8081 ebb = ebb->pred->src;
8085 loop->pre_header_edges = (edge *) xmalloc (num * sizeof (edge *));
8086 loop->num_pre_header_edges = num;
8088 /* Store edges in order that they are followed. The source
8089 of the first edge is the root node of the pre-header extended
8090 basic block and the destination of the last last edge is
8092 for (e = loop->entry_edges[0]; num; e = e->src->pred)
8094 loop->pre_header_edges[--num] = e;
8100 /* Return the block for the pre-header of the loop with header
8101 HEADER where DOM specifies the dominator information. Return NULL if
8102 there is no pre-header. */
8105 flow_loop_pre_header_find (header, dom)
8109 basic_block pre_header;
8112 /* If block p is a predecessor of the header and is the only block
8113 that the header does not dominate, then it is the pre-header. */
8115 for (e = header->pred; e; e = e->pred_next)
8117 basic_block node = e->src;
8119 if (node != ENTRY_BLOCK_PTR
8120 && ! TEST_BIT (dom[node->index], header->index))
8122 if (pre_header == NULL)
8126 /* There are multiple edges into the header from outside
8127 the loop so there is no pre-header block. */
8136 /* Add LOOP to the loop hierarchy tree where PREVLOOP was the loop
8137 previously added. The insertion algorithm assumes that the loops
8138 are added in the order found by a depth first search of the CFG. */
8141 flow_loop_tree_node_add (prevloop, loop)
8142 struct loop *prevloop;
8146 if (flow_loop_nested_p (prevloop, loop))
8148 prevloop->inner = loop;
8149 loop->outer = prevloop;
8153 while (prevloop->outer)
8155 if (flow_loop_nested_p (prevloop->outer, loop))
8157 prevloop->next = loop;
8158 loop->outer = prevloop->outer;
8161 prevloop = prevloop->outer;
8164 prevloop->next = loop;
8168 /* Build the loop hierarchy tree for LOOPS. */
8171 flow_loops_tree_build (loops)
8172 struct loops *loops;
8177 num_loops = loops->num;
8181 /* Root the loop hierarchy tree with the first loop found.
8182 Since we used a depth first search this should be the
8184 loops->tree = &loops->array[0];
8185 loops->tree->outer = loops->tree->inner = loops->tree->next = NULL;
8187 /* Add the remaining loops to the tree. */
8188 for (i = 1; i < num_loops; i++)
8189 flow_loop_tree_node_add (&loops->array[i - 1], &loops->array[i]);
8192 /* Helper function to compute loop nesting depth and enclosed loop level
8193 for the natural loop specified by LOOP at the loop depth DEPTH.
8194 Returns the loop level. */
8197 flow_loop_level_compute (loop, depth)
8207 /* Traverse loop tree assigning depth and computing level as the
8208 maximum level of all the inner loops of this loop. The loop
8209 level is equivalent to the height of the loop in the loop tree
8210 and corresponds to the number of enclosed loop levels (including
8212 for (inner = loop->inner; inner; inner = inner->next)
8216 ilevel = flow_loop_level_compute (inner, depth + 1) + 1;
8221 loop->level = level;
8222 loop->depth = depth;
8226 /* Compute the loop nesting depth and enclosed loop level for the loop
8227 hierarchy tree specfied by LOOPS. Return the maximum enclosed loop
8231 flow_loops_level_compute (loops)
8232 struct loops *loops;
8238 /* Traverse all the outer level loops. */
8239 for (loop = loops->tree; loop; loop = loop->next)
8241 level = flow_loop_level_compute (loop, 1);
8249 /* Scan a single natural loop specified by LOOP collecting information
8250 about it specified by FLAGS. */
8253 flow_loop_scan (loops, loop, flags)
8254 struct loops *loops;
8258 /* Determine prerequisites. */
8259 if ((flags & LOOP_EXITS_DOMS) && ! loop->exit_edges)
8260 flags |= LOOP_EXIT_EDGES;
8262 if (flags & LOOP_ENTRY_EDGES)
8264 /* Find edges which enter the loop header.
8265 Note that the entry edges should only
8266 enter the header of a natural loop. */
8268 = flow_loop_entry_edges_find (loop->header,
8270 &loop->entry_edges);
8273 if (flags & LOOP_EXIT_EDGES)
8275 /* Find edges which exit the loop. */
8277 = flow_loop_exit_edges_find (loop->nodes,
8281 if (flags & LOOP_EXITS_DOMS)
8285 /* Determine which loop nodes dominate all the exits
8287 loop->exits_doms = sbitmap_alloc (n_basic_blocks);
8288 sbitmap_copy (loop->exits_doms, loop->nodes);
8289 for (j = 0; j < loop->num_exits; j++)
8290 sbitmap_a_and_b (loop->exits_doms, loop->exits_doms,
8291 loops->cfg.dom[loop->exit_edges[j]->src->index]);
8293 /* The header of a natural loop must dominate
8295 if (! TEST_BIT (loop->exits_doms, loop->header->index))
8299 if (flags & LOOP_PRE_HEADER)
8301 /* Look to see if the loop has a pre-header node. */
8303 = flow_loop_pre_header_find (loop->header, loops->cfg.dom);
8305 /* Find the blocks within the extended basic block of
8306 the loop pre-header. */
8307 flow_loop_pre_header_scan (loop);
8313 /* Find all the natural loops in the function and save in LOOPS structure
8314 and recalculate loop_depth information in basic block structures.
8315 FLAGS controls which loop information is collected.
8316 Return the number of natural loops found. */
8319 flow_loops_find (loops, flags)
8320 struct loops *loops;
8332 /* This function cannot be repeatedly called with different
8333 flags to build up the loop information. The loop tree
8334 must always be built if this function is called. */
8335 if (! (flags & LOOP_TREE))
8338 memset (loops, 0, sizeof (*loops));
8340 /* Taking care of this degenerate case makes the rest of
8341 this code simpler. */
8342 if (n_basic_blocks == 0)
8348 /* Compute the dominators. */
8349 dom = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
8350 calculate_dominance_info (NULL, dom, CDI_DOMINATORS);
8352 /* Count the number of loop edges (back edges). This should be the
8353 same as the number of natural loops. */
8356 for (b = 0; b < n_basic_blocks; b++)
8360 header = BASIC_BLOCK (b);
8361 header->loop_depth = 0;
8363 for (e = header->pred; e; e = e->pred_next)
8365 basic_block latch = e->src;
8367 /* Look for back edges where a predecessor is dominated
8368 by this block. A natural loop has a single entry
8369 node (header) that dominates all the nodes in the
8370 loop. It also has single back edge to the header
8371 from a latch node. Note that multiple natural loops
8372 may share the same header. */
8373 if (b != header->index)
8376 if (latch != ENTRY_BLOCK_PTR && TEST_BIT (dom[latch->index], b))
8383 /* Compute depth first search order of the CFG so that outer
8384 natural loops will be found before inner natural loops. */
8385 dfs_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
8386 rc_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
8387 flow_depth_first_order_compute (dfs_order, rc_order);
8389 /* Save CFG derived information to avoid recomputing it. */
8390 loops->cfg.dom = dom;
8391 loops->cfg.dfs_order = dfs_order;
8392 loops->cfg.rc_order = rc_order;
8394 /* Allocate loop structures. */
8396 = (struct loop *) xcalloc (num_loops, sizeof (struct loop));
8398 headers = sbitmap_alloc (n_basic_blocks);
8399 sbitmap_zero (headers);
8401 loops->shared_headers = sbitmap_alloc (n_basic_blocks);
8402 sbitmap_zero (loops->shared_headers);
8404 /* Find and record information about all the natural loops
8407 for (b = 0; b < n_basic_blocks; b++)
8411 /* Search the nodes of the CFG in reverse completion order
8412 so that we can find outer loops first. */
8413 header = BASIC_BLOCK (rc_order[b]);
8415 /* Look for all the possible latch blocks for this header. */
8416 for (e = header->pred; e; e = e->pred_next)
8418 basic_block latch = e->src;
8420 /* Look for back edges where a predecessor is dominated
8421 by this block. A natural loop has a single entry
8422 node (header) that dominates all the nodes in the
8423 loop. It also has single back edge to the header
8424 from a latch node. Note that multiple natural loops
8425 may share the same header. */
8426 if (latch != ENTRY_BLOCK_PTR
8427 && TEST_BIT (dom[latch->index], header->index))
8431 loop = loops->array + num_loops;
8433 loop->header = header;
8434 loop->latch = latch;
8435 loop->num = num_loops;
8442 for (i = 0; i < num_loops; i++)
8444 struct loop *loop = &loops->array[i];
8446 /* Keep track of blocks that are loop headers so
8447 that we can tell which loops should be merged. */
8448 if (TEST_BIT (headers, loop->header->index))
8449 SET_BIT (loops->shared_headers, loop->header->index);
8450 SET_BIT (headers, loop->header->index);
8452 /* Find nodes contained within the loop. */
8453 loop->nodes = sbitmap_alloc (n_basic_blocks);
8455 = flow_loop_nodes_find (loop->header, loop->latch, loop->nodes);
8457 /* Compute first and last blocks within the loop.
8458 These are often the same as the loop header and
8459 loop latch respectively, but this is not always
8462 = BASIC_BLOCK (sbitmap_first_set_bit (loop->nodes));
8464 = BASIC_BLOCK (sbitmap_last_set_bit (loop->nodes));
8466 flow_loop_scan (loops, loop, flags);
8469 /* Natural loops with shared headers may either be disjoint or
8470 nested. Disjoint loops with shared headers cannot be inner
8471 loops and should be merged. For now just mark loops that share
8473 for (i = 0; i < num_loops; i++)
8474 if (TEST_BIT (loops->shared_headers, loops->array[i].header->index))
8475 loops->array[i].shared = 1;
8477 sbitmap_free (headers);
8480 loops->num = num_loops;
8482 /* Build the loop hierarchy tree. */
8483 flow_loops_tree_build (loops);
8485 /* Assign the loop nesting depth and enclosed loop level for each
8487 loops->levels = flow_loops_level_compute (loops);
8493 /* Update the information regarding the loops in the CFG
8494 specified by LOOPS. */
8496 flow_loops_update (loops, flags)
8497 struct loops *loops;
8500 /* One day we may want to update the current loop data. For now
8501 throw away the old stuff and rebuild what we need. */
8503 flow_loops_free (loops);
8505 return flow_loops_find (loops, flags);
8509 /* Return non-zero if edge E enters header of LOOP from outside of LOOP. */
8512 flow_loop_outside_edge_p (loop, e)
8513 const struct loop *loop;
8516 if (e->dest != loop->header)
8518 return (e->src == ENTRY_BLOCK_PTR)
8519 || ! TEST_BIT (loop->nodes, e->src->index);
8522 /* Clear LOG_LINKS fields of insns in a chain.
8523 Also clear the global_live_at_{start,end} fields of the basic block
8527 clear_log_links (insns)
8533 for (i = insns; i; i = NEXT_INSN (i))
8537 for (b = 0; b < n_basic_blocks; b++)
8539 basic_block bb = BASIC_BLOCK (b);
8541 bb->global_live_at_start = NULL;
8542 bb->global_live_at_end = NULL;
8545 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
8546 EXIT_BLOCK_PTR->global_live_at_start = NULL;
8549 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
8550 correspond to the hard registers, if any, set in that map. This
8551 could be done far more efficiently by having all sorts of special-cases
8552 with moving single words, but probably isn't worth the trouble. */
8555 reg_set_to_hard_reg_set (to, from)
8561 EXECUTE_IF_SET_IN_BITMAP
8564 if (i >= FIRST_PSEUDO_REGISTER)
8566 SET_HARD_REG_BIT (*to, i);
8570 /* Called once at intialization time. */
8575 static int initialized;
8579 gcc_obstack_init (&flow_obstack);
8580 flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);
8585 obstack_free (&flow_obstack, flow_firstobj);
8586 flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);