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"
136 #include "insn-flags.h"
141 #include "splay-tree.h"
143 #define obstack_chunk_alloc xmalloc
144 #define obstack_chunk_free free
146 /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
147 the stack pointer does not matter. The value is tested only in
148 functions that have frame pointers.
149 No definition is equivalent to always zero. */
150 #ifndef EXIT_IGNORE_STACK
151 #define EXIT_IGNORE_STACK 0
154 #ifndef HAVE_epilogue
155 #define HAVE_epilogue 0
157 #ifndef HAVE_prologue
158 #define HAVE_prologue 0
160 #ifndef HAVE_sibcall_epilogue
161 #define HAVE_sibcall_epilogue 0
165 #define LOCAL_REGNO(REGNO) 0
167 #ifndef EPILOGUE_USES
168 #define EPILOGUE_USES(REGNO) 0
171 #ifdef HAVE_conditional_execution
172 #ifndef REVERSE_CONDEXEC_PREDICATES_P
173 #define REVERSE_CONDEXEC_PREDICATES_P(x, y) ((x) == reverse_condition (y))
177 /* The obstack on which the flow graph components are allocated. */
179 struct obstack flow_obstack;
180 static char *flow_firstobj;
182 /* Number of basic blocks in the current function. */
186 /* Number of edges in the current function. */
190 /* The basic block array. */
192 varray_type basic_block_info;
194 /* The special entry and exit blocks. */
196 struct basic_block_def entry_exit_blocks[2]
201 NULL, /* local_set */
202 NULL, /* cond_local_set */
203 NULL, /* global_live_at_start */
204 NULL, /* global_live_at_end */
206 ENTRY_BLOCK, /* index */
208 -1, -1, /* eh_beg, eh_end */
216 NULL, /* local_set */
217 NULL, /* cond_local_set */
218 NULL, /* global_live_at_start */
219 NULL, /* global_live_at_end */
221 EXIT_BLOCK, /* index */
223 -1, -1, /* eh_beg, eh_end */
228 /* Nonzero if the second flow pass has completed. */
231 /* Maximum register number used in this function, plus one. */
235 /* Indexed by n, giving various register information */
237 varray_type reg_n_info;
239 /* Size of a regset for the current function,
240 in (1) bytes and (2) elements. */
245 /* Regset of regs live when calls to `setjmp'-like functions happen. */
246 /* ??? Does this exist only for the setjmp-clobbered warning message? */
248 regset regs_live_at_setjmp;
250 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
251 that have to go in the same hard reg.
252 The first two regs in the list are a pair, and the next two
253 are another pair, etc. */
256 /* Callback that determines if it's ok for a function to have no
257 noreturn attribute. */
258 int (*lang_missing_noreturn_ok_p) PARAMS ((tree));
260 /* Set of registers that may be eliminable. These are handled specially
261 in updating regs_ever_live. */
263 static HARD_REG_SET elim_reg_set;
265 /* The basic block structure for every insn, indexed by uid. */
267 varray_type basic_block_for_insn;
269 /* The labels mentioned in non-jump rtl. Valid during find_basic_blocks. */
270 /* ??? Should probably be using LABEL_NUSES instead. It would take a
271 bit of surgery to be able to use or co-opt the routines in jump. */
273 static rtx label_value_list;
274 static rtx tail_recursion_label_list;
276 /* Holds information for tracking conditional register life information. */
277 struct reg_cond_life_info
279 /* An EXPR_LIST of conditions under which a register is dead. */
282 /* ??? Could store mask of bytes that are dead, so that we could finally
283 track lifetimes of multi-word registers accessed via subregs. */
286 /* For use in communicating between propagate_block and its subroutines.
287 Holds all information needed to compute life and def-use information. */
289 struct propagate_block_info
291 /* The basic block we're considering. */
294 /* Bit N is set if register N is conditionally or unconditionally live. */
297 /* Bit N is set if register N is set this insn. */
300 /* Element N is the next insn that uses (hard or pseudo) register N
301 within the current basic block; or zero, if there is no such insn. */
304 /* Contains a list of all the MEMs we are tracking for dead store
308 /* If non-null, record the set of registers set unconditionally in the
312 /* If non-null, record the set of registers set conditionally in the
314 regset cond_local_set;
316 #ifdef HAVE_conditional_execution
317 /* Indexed by register number, holds a reg_cond_life_info for each
318 register that is not unconditionally live or dead. */
319 splay_tree reg_cond_dead;
321 /* Bit N is set if register N is in an expression in reg_cond_dead. */
325 /* The length of mem_set_list. */
326 int mem_set_list_len;
328 /* Non-zero if the value of CC0 is live. */
331 /* Flags controling the set of information propagate_block collects. */
335 /* Maximum length of pbi->mem_set_list before we start dropping
336 new elements on the floor. */
337 #define MAX_MEM_SET_LIST_LEN 100
339 /* Store the data structures necessary for depth-first search. */
340 struct depth_first_search_dsS {
341 /* stack for backtracking during the algorithm */
344 /* number of edges in the stack. That is, positions 0, ..., sp-1
348 /* record of basic blocks already seen by depth-first search */
349 sbitmap visited_blocks;
351 typedef struct depth_first_search_dsS *depth_first_search_ds;
353 /* Have print_rtl_and_abort give the same information that fancy_abort
355 #define print_rtl_and_abort() \
356 print_rtl_and_abort_fcn (__FILE__, __LINE__, __FUNCTION__)
358 /* Forward declarations */
359 static int count_basic_blocks PARAMS ((rtx));
360 static void find_basic_blocks_1 PARAMS ((rtx));
361 static rtx find_label_refs PARAMS ((rtx, rtx));
362 static void clear_edges PARAMS ((void));
363 static void make_edges PARAMS ((rtx));
364 static void make_label_edge PARAMS ((sbitmap *, basic_block,
366 static void make_eh_edge PARAMS ((sbitmap *, eh_nesting_info *,
367 basic_block, rtx, int));
368 static void mark_critical_edges PARAMS ((void));
369 static void move_stray_eh_region_notes PARAMS ((void));
370 static void record_active_eh_regions PARAMS ((rtx));
372 static void commit_one_edge_insertion PARAMS ((edge));
374 static void delete_unreachable_blocks PARAMS ((void));
375 static void delete_eh_regions PARAMS ((void));
376 static int can_delete_note_p PARAMS ((rtx));
377 static void expunge_block PARAMS ((basic_block));
378 static int can_delete_label_p PARAMS ((rtx));
379 static int tail_recursion_label_p PARAMS ((rtx));
380 static int merge_blocks_move_predecessor_nojumps PARAMS ((basic_block,
382 static int merge_blocks_move_successor_nojumps PARAMS ((basic_block,
384 static int merge_blocks PARAMS ((edge,basic_block,basic_block));
385 static void try_merge_blocks PARAMS ((void));
386 static void tidy_fallthru_edges PARAMS ((void));
387 static int verify_wide_reg_1 PARAMS ((rtx *, void *));
388 static void verify_wide_reg PARAMS ((int, rtx, rtx));
389 static void verify_local_live_at_start PARAMS ((regset, basic_block));
390 static int set_noop_p PARAMS ((rtx));
391 static int noop_move_p PARAMS ((rtx));
392 static void delete_noop_moves PARAMS ((rtx));
393 static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
394 static void notice_stack_pointer_modification PARAMS ((rtx));
395 static void mark_reg PARAMS ((rtx, void *));
396 static void mark_regs_live_at_end PARAMS ((regset));
397 static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
398 static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
399 static void propagate_block_delete_insn PARAMS ((basic_block, rtx));
400 static rtx propagate_block_delete_libcall PARAMS ((basic_block, rtx, rtx));
401 static int insn_dead_p PARAMS ((struct propagate_block_info *,
403 static int libcall_dead_p PARAMS ((struct propagate_block_info *,
405 static void mark_set_regs PARAMS ((struct propagate_block_info *,
407 static void mark_set_1 PARAMS ((struct propagate_block_info *,
408 enum rtx_code, rtx, rtx,
410 #ifdef HAVE_conditional_execution
411 static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
413 static void free_reg_cond_life_info PARAMS ((splay_tree_value));
414 static int flush_reg_cond_reg_1 PARAMS ((splay_tree_node, void *));
415 static void flush_reg_cond_reg PARAMS ((struct propagate_block_info *,
417 static rtx elim_reg_cond PARAMS ((rtx, unsigned int));
418 static rtx ior_reg_cond PARAMS ((rtx, rtx, int));
419 static rtx not_reg_cond PARAMS ((rtx));
420 static rtx and_reg_cond PARAMS ((rtx, rtx, int));
423 static void attempt_auto_inc PARAMS ((struct propagate_block_info *,
424 rtx, rtx, rtx, rtx, rtx));
425 static void find_auto_inc PARAMS ((struct propagate_block_info *,
427 static int try_pre_increment_1 PARAMS ((struct propagate_block_info *,
429 static int try_pre_increment PARAMS ((rtx, rtx, HOST_WIDE_INT));
431 static void mark_used_reg PARAMS ((struct propagate_block_info *,
433 static void mark_used_regs PARAMS ((struct propagate_block_info *,
435 void dump_flow_info PARAMS ((FILE *));
436 void debug_flow_info PARAMS ((void));
437 static void dump_edge_info PARAMS ((FILE *, edge, int));
438 static void print_rtl_and_abort_fcn PARAMS ((const char *, int,
442 static void invalidate_mems_from_autoinc PARAMS ((struct propagate_block_info *,
444 static void invalidate_mems_from_set PARAMS ((struct propagate_block_info *,
446 static void remove_fake_successors PARAMS ((basic_block));
447 static void flow_nodes_print PARAMS ((const char *, const sbitmap,
449 static void flow_edge_list_print PARAMS ((const char *, const edge *,
451 static void flow_loops_cfg_dump PARAMS ((const struct loops *,
453 static int flow_loop_nested_p PARAMS ((struct loop *,
455 static int flow_loop_entry_edges_find PARAMS ((basic_block, const sbitmap,
457 static int flow_loop_exit_edges_find PARAMS ((const sbitmap, edge **));
458 static int flow_loop_nodes_find PARAMS ((basic_block, basic_block, sbitmap));
459 static int flow_depth_first_order_compute PARAMS ((int *, int *));
460 static void flow_dfs_compute_reverse_init
461 PARAMS ((depth_first_search_ds));
462 static void flow_dfs_compute_reverse_add_bb
463 PARAMS ((depth_first_search_ds, basic_block));
464 static basic_block flow_dfs_compute_reverse_execute
465 PARAMS ((depth_first_search_ds));
466 static void flow_dfs_compute_reverse_finish
467 PARAMS ((depth_first_search_ds));
468 static void flow_loop_pre_header_scan PARAMS ((struct loop *));
469 static basic_block flow_loop_pre_header_find PARAMS ((basic_block,
471 static void flow_loop_tree_node_add PARAMS ((struct loop *, struct loop *));
472 static void flow_loops_tree_build PARAMS ((struct loops *));
473 static int flow_loop_level_compute PARAMS ((struct loop *, int));
474 static int flow_loops_level_compute PARAMS ((struct loops *));
475 static void allocate_bb_life_data PARAMS ((void));
476 static void find_sub_basic_blocks PARAMS ((basic_block));
478 /* Find basic blocks of the current function.
479 F is the first insn of the function and NREGS the number of register
483 find_basic_blocks (f, nregs, file)
485 int nregs ATTRIBUTE_UNUSED;
486 FILE *file ATTRIBUTE_UNUSED;
490 /* Flush out existing data. */
491 if (basic_block_info != NULL)
497 /* Clear bb->aux on all extant basic blocks. We'll use this as a
498 tag for reuse during create_basic_block, just in case some pass
499 copies around basic block notes improperly. */
500 for (i = 0; i < n_basic_blocks; ++i)
501 BASIC_BLOCK (i)->aux = NULL;
503 VARRAY_FREE (basic_block_info);
506 n_basic_blocks = count_basic_blocks (f);
508 /* Size the basic block table. The actual structures will be allocated
509 by find_basic_blocks_1, since we want to keep the structure pointers
510 stable across calls to find_basic_blocks. */
511 /* ??? This whole issue would be much simpler if we called find_basic_blocks
512 exactly once, and thereafter we don't have a single long chain of
513 instructions at all until close to the end of compilation when we
514 actually lay them out. */
516 VARRAY_BB_INIT (basic_block_info, n_basic_blocks, "basic_block_info");
518 find_basic_blocks_1 (f);
520 /* Record the block to which an insn belongs. */
521 /* ??? This should be done another way, by which (perhaps) a label is
522 tagged directly with the basic block that it starts. It is used for
523 more than that currently, but IMO that is the only valid use. */
525 max_uid = get_max_uid ();
527 /* Leave space for insns life_analysis makes in some cases for auto-inc.
528 These cases are rare, so we don't need too much space. */
529 max_uid += max_uid / 10;
532 compute_bb_for_insn (max_uid);
534 /* Discover the edges of our cfg. */
535 record_active_eh_regions (f);
536 make_edges (label_value_list);
538 /* Do very simple cleanup now, for the benefit of code that runs between
539 here and cleanup_cfg, e.g. thread_prologue_and_epilogue_insns. */
540 tidy_fallthru_edges ();
542 mark_critical_edges ();
544 #ifdef ENABLE_CHECKING
550 check_function_return_warnings ()
552 if (warn_missing_noreturn
553 && !TREE_THIS_VOLATILE (cfun->decl)
554 && EXIT_BLOCK_PTR->pred == NULL
555 && (lang_missing_noreturn_ok_p
556 && !lang_missing_noreturn_ok_p (cfun->decl)))
557 warning ("function might be possible candidate for attribute `noreturn'");
559 /* If we have a path to EXIT, then we do return. */
560 if (TREE_THIS_VOLATILE (cfun->decl)
561 && EXIT_BLOCK_PTR->pred != NULL)
562 warning ("`noreturn' function does return");
564 /* If the clobber_return_insn appears in some basic block, then we
565 do reach the end without returning a value. */
566 else if (warn_return_type
567 && cfun->x_clobber_return_insn != NULL
568 && EXIT_BLOCK_PTR->pred != NULL)
570 int max_uid = get_max_uid ();
572 /* If clobber_return_insn was excised by jump1, then renumber_insns
573 can make max_uid smaller than the number still recorded in our rtx.
574 That's fine, since this is a quick way of verifying that the insn
575 is no longer in the chain. */
576 if (INSN_UID (cfun->x_clobber_return_insn) < max_uid)
578 /* Recompute insn->block mapping, since the initial mapping is
579 set before we delete unreachable blocks. */
580 compute_bb_for_insn (max_uid);
582 if (BLOCK_FOR_INSN (cfun->x_clobber_return_insn) != NULL)
583 warning ("control reaches end of non-void function");
588 /* Count the basic blocks of the function. */
591 count_basic_blocks (f)
595 register RTX_CODE prev_code;
596 register int count = 0;
598 int call_had_abnormal_edge = 0;
600 prev_code = JUMP_INSN;
601 for (insn = f; insn; insn = NEXT_INSN (insn))
603 register RTX_CODE code = GET_CODE (insn);
605 if (code == CODE_LABEL
606 || (GET_RTX_CLASS (code) == 'i'
607 && (prev_code == JUMP_INSN
608 || prev_code == BARRIER
609 || (prev_code == CALL_INSN && call_had_abnormal_edge))))
612 /* Record whether this call created an edge. */
613 if (code == CALL_INSN)
615 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
616 int region = (note ? INTVAL (XEXP (note, 0)) : 1);
618 call_had_abnormal_edge = 0;
620 /* If there is an EH region or rethrow, we have an edge. */
621 if ((eh_region && region > 0)
622 || find_reg_note (insn, REG_EH_RETHROW, NULL_RTX))
623 call_had_abnormal_edge = 1;
624 else if (nonlocal_goto_handler_labels && region >= 0)
625 /* If there is a nonlocal goto label and the specified
626 region number isn't -1, we have an edge. (0 means
627 no throw, but might have a nonlocal goto). */
628 call_had_abnormal_edge = 1;
633 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
635 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
639 /* The rest of the compiler works a bit smoother when we don't have to
640 check for the edge case of do-nothing functions with no basic blocks. */
643 emit_insn (gen_rtx_USE (VOIDmode, const0_rtx));
650 /* Scan a list of insns for labels referred to other than by jumps.
651 This is used to scan the alternatives of a call placeholder. */
653 find_label_refs (f, lvl)
659 for (insn = f; insn; insn = NEXT_INSN (insn))
660 if (INSN_P (insn) && GET_CODE (insn) != JUMP_INSN)
664 /* Make a list of all labels referred to other than by jumps
665 (which just don't have the REG_LABEL notes).
667 Make a special exception for labels followed by an ADDR*VEC,
668 as this would be a part of the tablejump setup code.
670 Make a special exception for the eh_return_stub_label, which
671 we know isn't part of any otherwise visible control flow.
673 Make a special exception to registers loaded with label
674 values just before jump insns that use them. */
676 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
677 if (REG_NOTE_KIND (note) == REG_LABEL)
679 rtx lab = XEXP (note, 0), next;
681 if (lab == eh_return_stub_label)
683 else if ((next = next_nonnote_insn (lab)) != NULL
684 && GET_CODE (next) == JUMP_INSN
685 && (GET_CODE (PATTERN (next)) == ADDR_VEC
686 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
688 else if (GET_CODE (lab) == NOTE)
690 else if (GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
691 && find_reg_note (NEXT_INSN (insn), REG_LABEL, lab))
694 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
701 /* Assume that someone emitted code with control flow instructions to the
702 basic block. Update the data structure. */
704 find_sub_basic_blocks (bb)
707 rtx first_insn = bb->head, insn;
709 edge succ_list = bb->succ;
710 rtx jump_insn = NULL_RTX;
714 basic_block first_bb = bb, last_bb;
717 if (GET_CODE (first_insn) == LABEL_REF)
718 first_insn = NEXT_INSN (first_insn);
719 first_insn = NEXT_INSN (first_insn);
723 /* Scan insn chain and try to find new basic block boundaries. */
726 enum rtx_code code = GET_CODE (insn);
730 /* We need some special care for those expressions. */
731 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
732 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
741 /* On code label, split current basic block. */
743 falltru = split_block (bb, PREV_INSN (insn));
748 remove_edge (falltru);
752 if (LABEL_ALTERNATE_NAME (insn))
753 make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0);
756 /* In case we've previously split insn on the JUMP_INSN, move the
757 block header to proper place. */
760 falltru = split_block (bb, PREV_INSN (insn));
770 insn = NEXT_INSN (insn);
772 /* Last basic block must end in the original BB end. */
776 /* Wire in the original edges for last basic block. */
779 bb->succ = succ_list;
781 succ_list->src = bb, succ_list = succ_list->succ_next;
784 bb->succ = succ_list;
786 /* Now re-scan and wire in all edges. This expect simple (conditional)
787 jumps at the end of each new basic blocks. */
789 for (i = first_bb->index; i < last_bb->index; i++)
791 bb = BASIC_BLOCK (i);
792 if (GET_CODE (bb->end) == JUMP_INSN)
794 mark_jump_label (PATTERN (bb->end), bb->end, 0, 0);
795 make_label_edge (NULL, bb, JUMP_LABEL (bb->end), 0);
797 insn = NEXT_INSN (insn);
801 /* Find all basic blocks of the function whose first insn is F.
803 Collect and return a list of labels whose addresses are taken. This
804 will be used in make_edges for use with computed gotos. */
807 find_basic_blocks_1 (f)
810 register rtx insn, next;
812 rtx bb_note = NULL_RTX;
813 rtx eh_list = NULL_RTX;
819 /* We process the instructions in a slightly different way than we did
820 previously. This is so that we see a NOTE_BASIC_BLOCK after we have
821 closed out the previous block, so that it gets attached at the proper
822 place. Since this form should be equivalent to the previous,
823 count_basic_blocks continues to use the old form as a check. */
825 for (insn = f; insn; insn = next)
827 enum rtx_code code = GET_CODE (insn);
829 next = NEXT_INSN (insn);
835 int kind = NOTE_LINE_NUMBER (insn);
837 /* Keep a LIFO list of the currently active exception notes. */
838 if (kind == NOTE_INSN_EH_REGION_BEG)
839 eh_list = alloc_INSN_LIST (insn, eh_list);
840 else if (kind == NOTE_INSN_EH_REGION_END)
844 eh_list = XEXP (eh_list, 1);
845 free_INSN_LIST_node (t);
848 /* Look for basic block notes with which to keep the
849 basic_block_info pointers stable. Unthread the note now;
850 we'll put it back at the right place in create_basic_block.
851 Or not at all if we've already found a note in this block. */
852 else if (kind == NOTE_INSN_BASIC_BLOCK)
854 if (bb_note == NULL_RTX)
857 next = flow_delete_insn (insn);
863 /* A basic block starts at a label. If we've closed one off due
864 to a barrier or some such, no need to do it again. */
865 if (head != NULL_RTX)
867 /* While we now have edge lists with which other portions of
868 the compiler might determine a call ending a basic block
869 does not imply an abnormal edge, it will be a bit before
870 everything can be updated. So continue to emit a noop at
871 the end of such a block. */
872 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
874 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
875 end = emit_insn_after (nop, end);
878 create_basic_block (i++, head, end, bb_note);
886 /* A basic block ends at a jump. */
887 if (head == NULL_RTX)
891 /* ??? Make a special check for table jumps. The way this
892 happens is truly and amazingly gross. We are about to
893 create a basic block that contains just a code label and
894 an addr*vec jump insn. Worse, an addr_diff_vec creates
895 its own natural loop.
897 Prevent this bit of brain damage, pasting things together
898 correctly in make_edges.
900 The correct solution involves emitting the table directly
901 on the tablejump instruction as a note, or JUMP_LABEL. */
903 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
904 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
912 goto new_bb_inclusive;
915 /* A basic block ends at a barrier. It may be that an unconditional
916 jump already closed the basic block -- no need to do it again. */
917 if (head == NULL_RTX)
920 /* While we now have edge lists with which other portions of the
921 compiler might determine a call ending a basic block does not
922 imply an abnormal edge, it will be a bit before everything can
923 be updated. So continue to emit a noop at the end of such a
925 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
927 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
928 end = emit_insn_after (nop, end);
930 goto new_bb_exclusive;
934 /* Record whether this call created an edge. */
935 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
936 int region = (note ? INTVAL (XEXP (note, 0)) : 1);
937 int call_has_abnormal_edge = 0;
939 if (GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
941 /* Scan each of the alternatives for label refs. */
942 lvl = find_label_refs (XEXP (PATTERN (insn), 0), lvl);
943 lvl = find_label_refs (XEXP (PATTERN (insn), 1), lvl);
944 lvl = find_label_refs (XEXP (PATTERN (insn), 2), lvl);
945 /* Record its tail recursion label, if any. */
946 if (XEXP (PATTERN (insn), 3) != NULL_RTX)
947 trll = alloc_EXPR_LIST (0, XEXP (PATTERN (insn), 3), trll);
950 /* If there is an EH region or rethrow, we have an edge. */
951 if ((eh_list && region > 0)
952 || find_reg_note (insn, REG_EH_RETHROW, NULL_RTX))
953 call_has_abnormal_edge = 1;
954 else if (nonlocal_goto_handler_labels && region >= 0)
955 /* If there is a nonlocal goto label and the specified
956 region number isn't -1, we have an edge. (0 means
957 no throw, but might have a nonlocal goto). */
958 call_has_abnormal_edge = 1;
960 /* A basic block ends at a call that can either throw or
961 do a non-local goto. */
962 if (call_has_abnormal_edge)
965 if (head == NULL_RTX)
970 create_basic_block (i++, head, end, bb_note);
971 head = end = NULL_RTX;
979 if (GET_RTX_CLASS (code) == 'i')
981 if (head == NULL_RTX)
988 if (GET_RTX_CLASS (code) == 'i'
989 && GET_CODE (insn) != JUMP_INSN)
993 /* Make a list of all labels referred to other than by jumps.
995 Make a special exception for labels followed by an ADDR*VEC,
996 as this would be a part of the tablejump setup code.
998 Make a special exception for the eh_return_stub_label, which
999 we know isn't part of any otherwise visible control flow.
1001 Make a special exception to registers loaded with label
1002 values just before jump insns that use them. */
1004 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1005 if (REG_NOTE_KIND (note) == REG_LABEL)
1007 rtx lab = XEXP (note, 0), next;
1009 if (lab == eh_return_stub_label)
1011 else if ((next = next_nonnote_insn (lab)) != NULL
1012 && GET_CODE (next) == JUMP_INSN
1013 && (GET_CODE (PATTERN (next)) == ADDR_VEC
1014 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
1016 else if (GET_CODE (lab) == NOTE)
1018 else if (GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
1019 && find_reg_note (NEXT_INSN (insn), REG_LABEL, lab))
1022 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
1027 if (head != NULL_RTX)
1028 create_basic_block (i++, head, end, bb_note);
1030 flow_delete_insn (bb_note);
1032 if (i != n_basic_blocks)
1035 label_value_list = lvl;
1036 tail_recursion_label_list = trll;
1039 /* Tidy the CFG by deleting unreachable code and whatnot. */
1045 delete_unreachable_blocks ();
1046 move_stray_eh_region_notes ();
1047 record_active_eh_regions (f);
1048 try_merge_blocks ();
1049 mark_critical_edges ();
1051 /* Kill the data we won't maintain. */
1052 free_EXPR_LIST_list (&label_value_list);
1053 free_EXPR_LIST_list (&tail_recursion_label_list);
1056 /* Create a new basic block consisting of the instructions between
1057 HEAD and END inclusive. Reuses the note and basic block struct
1058 in BB_NOTE, if any. */
1061 create_basic_block (index, head, end, bb_note)
1063 rtx head, end, bb_note;
1068 && ! RTX_INTEGRATED_P (bb_note)
1069 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
1072 /* If we found an existing note, thread it back onto the chain. */
1076 if (GET_CODE (head) == CODE_LABEL)
1080 after = PREV_INSN (head);
1084 if (after != bb_note && NEXT_INSN (after) != bb_note)
1085 reorder_insns (bb_note, bb_note, after);
1089 /* Otherwise we must create a note and a basic block structure.
1090 Since we allow basic block structs in rtl, give the struct
1091 the same lifetime by allocating it off the function obstack
1092 rather than using malloc. */
1094 bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*bb));
1095 memset (bb, 0, sizeof (*bb));
1097 if (GET_CODE (head) == CODE_LABEL)
1098 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
1101 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
1104 NOTE_BASIC_BLOCK (bb_note) = bb;
1107 /* Always include the bb note in the block. */
1108 if (NEXT_INSN (end) == bb_note)
1114 BASIC_BLOCK (index) = bb;
1116 /* Tag the block so that we know it has been used when considering
1117 other basic block notes. */
1121 /* Records the basic block struct in BB_FOR_INSN, for every instruction
1122 indexed by INSN_UID. MAX is the size of the array. */
1125 compute_bb_for_insn (max)
1130 if (basic_block_for_insn)
1131 VARRAY_FREE (basic_block_for_insn);
1132 VARRAY_BB_INIT (basic_block_for_insn, max, "basic_block_for_insn");
1134 for (i = 0; i < n_basic_blocks; ++i)
1136 basic_block bb = BASIC_BLOCK (i);
1143 int uid = INSN_UID (insn);
1145 VARRAY_BB (basic_block_for_insn, uid) = bb;
1148 insn = NEXT_INSN (insn);
1153 /* Free the memory associated with the edge structures. */
1161 for (i = 0; i < n_basic_blocks; ++i)
1163 basic_block bb = BASIC_BLOCK (i);
1165 for (e = bb->succ; e; e = n)
1175 for (e = ENTRY_BLOCK_PTR->succ; e; e = n)
1181 ENTRY_BLOCK_PTR->succ = 0;
1182 EXIT_BLOCK_PTR->pred = 0;
1187 /* Identify the edges between basic blocks.
1189 NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks
1190 that are otherwise unreachable may be reachable with a non-local goto.
1192 BB_EH_END is an array indexed by basic block number in which we record
1193 the list of exception regions active at the end of the basic block. */
1196 make_edges (label_value_list)
1197 rtx label_value_list;
1200 eh_nesting_info *eh_nest_info = init_eh_nesting_info ();
1201 sbitmap *edge_cache = NULL;
1203 /* Assume no computed jump; revise as we create edges. */
1204 current_function_has_computed_jump = 0;
1206 /* Heavy use of computed goto in machine-generated code can lead to
1207 nearly fully-connected CFGs. In that case we spend a significant
1208 amount of time searching the edge lists for duplicates. */
1209 if (forced_labels || label_value_list)
1211 edge_cache = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
1212 sbitmap_vector_zero (edge_cache, n_basic_blocks);
1215 /* By nature of the way these get numbered, block 0 is always the entry. */
1216 make_edge (edge_cache, ENTRY_BLOCK_PTR, BASIC_BLOCK (0), EDGE_FALLTHRU);
1218 for (i = 0; i < n_basic_blocks; ++i)
1220 basic_block bb = BASIC_BLOCK (i);
1223 int force_fallthru = 0;
1225 if (GET_CODE (bb->head) == CODE_LABEL
1226 && LABEL_ALTERNATE_NAME (bb->head))
1227 make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0);
1229 /* Examine the last instruction of the block, and discover the
1230 ways we can leave the block. */
1233 code = GET_CODE (insn);
1236 if (code == JUMP_INSN)
1240 /* Recognize a non-local goto as a branch outside the
1241 current function. */
1242 if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX))
1245 /* ??? Recognize a tablejump and do the right thing. */
1246 else if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1247 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1248 && GET_CODE (tmp) == JUMP_INSN
1249 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1250 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1255 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1256 vec = XVEC (PATTERN (tmp), 0);
1258 vec = XVEC (PATTERN (tmp), 1);
1260 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1261 make_label_edge (edge_cache, bb,
1262 XEXP (RTVEC_ELT (vec, j), 0), 0);
1264 /* Some targets (eg, ARM) emit a conditional jump that also
1265 contains the out-of-range target. Scan for these and
1266 add an edge if necessary. */
1267 if ((tmp = single_set (insn)) != NULL
1268 && SET_DEST (tmp) == pc_rtx
1269 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1270 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF)
1271 make_label_edge (edge_cache, bb,
1272 XEXP (XEXP (SET_SRC (tmp), 2), 0), 0);
1274 #ifdef CASE_DROPS_THROUGH
1275 /* Silly VAXen. The ADDR_VEC is going to be in the way of
1276 us naturally detecting fallthru into the next block. */
1281 /* If this is a computed jump, then mark it as reaching
1282 everything on the label_value_list and forced_labels list. */
1283 else if (computed_jump_p (insn))
1285 current_function_has_computed_jump = 1;
1287 for (x = label_value_list; x; x = XEXP (x, 1))
1288 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1290 for (x = forced_labels; x; x = XEXP (x, 1))
1291 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1294 /* Returns create an exit out. */
1295 else if (returnjump_p (insn))
1296 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, 0);
1298 /* Otherwise, we have a plain conditional or unconditional jump. */
1301 if (! JUMP_LABEL (insn))
1303 make_label_edge (edge_cache, bb, JUMP_LABEL (insn), 0);
1307 /* If this is a sibling call insn, then this is in effect a
1308 combined call and return, and so we need an edge to the
1309 exit block. No need to worry about EH edges, since we
1310 wouldn't have created the sibling call in the first place. */
1312 if (code == CALL_INSN && SIBLING_CALL_P (insn))
1313 make_edge (edge_cache, bb, EXIT_BLOCK_PTR,
1314 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1316 /* If this is a CALL_INSN, then mark it as reaching the active EH
1317 handler for this CALL_INSN. If we're handling asynchronous
1318 exceptions then any insn can reach any of the active handlers.
1320 Also mark the CALL_INSN as reaching any nonlocal goto handler. */
1322 else if (code == CALL_INSN || asynchronous_exceptions)
1324 /* Add any appropriate EH edges. We do this unconditionally
1325 since there may be a REG_EH_REGION or REG_EH_RETHROW note
1326 on the call, and this needn't be within an EH region. */
1327 make_eh_edge (edge_cache, eh_nest_info, bb, insn, bb->eh_end);
1329 /* If we have asynchronous exceptions, do the same for *all*
1330 exception regions active in the block. */
1331 if (asynchronous_exceptions
1332 && bb->eh_beg != bb->eh_end)
1334 if (bb->eh_beg >= 0)
1335 make_eh_edge (edge_cache, eh_nest_info, bb,
1336 NULL_RTX, bb->eh_beg);
1338 for (x = bb->head; x != bb->end; x = NEXT_INSN (x))
1339 if (GET_CODE (x) == NOTE
1340 && (NOTE_LINE_NUMBER (x) == NOTE_INSN_EH_REGION_BEG
1341 || NOTE_LINE_NUMBER (x) == NOTE_INSN_EH_REGION_END))
1343 int region = NOTE_EH_HANDLER (x);
1344 make_eh_edge (edge_cache, eh_nest_info, bb,
1349 if (code == CALL_INSN && nonlocal_goto_handler_labels)
1351 /* ??? This could be made smarter: in some cases it's possible
1352 to tell that certain calls will not do a nonlocal goto.
1354 For example, if the nested functions that do the nonlocal
1355 gotos do not have their addresses taken, then only calls to
1356 those functions or to other nested functions that use them
1357 could possibly do nonlocal gotos. */
1358 /* We do know that a REG_EH_REGION note with a value less
1359 than 0 is guaranteed not to perform a non-local goto. */
1360 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
1361 if (!note || INTVAL (XEXP (note, 0)) >= 0)
1362 for (x = nonlocal_goto_handler_labels; x; x = XEXP (x, 1))
1363 make_label_edge (edge_cache, bb, XEXP (x, 0),
1364 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1368 /* We know something about the structure of the function __throw in
1369 libgcc2.c. It is the only function that ever contains eh_stub
1370 labels. It modifies its return address so that the last block
1371 returns to one of the eh_stub labels within it. So we have to
1372 make additional edges in the flow graph. */
1373 if (i + 1 == n_basic_blocks && eh_return_stub_label != 0)
1374 make_label_edge (edge_cache, bb, eh_return_stub_label, EDGE_EH);
1376 /* Find out if we can drop through to the next block. */
1377 insn = next_nonnote_insn (insn);
1378 if (!insn || (i + 1 == n_basic_blocks && force_fallthru))
1379 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU);
1380 else if (i + 1 < n_basic_blocks)
1382 rtx tmp = BLOCK_HEAD (i + 1);
1383 if (GET_CODE (tmp) == NOTE)
1384 tmp = next_nonnote_insn (tmp);
1385 if (force_fallthru || insn == tmp)
1386 make_edge (edge_cache, bb, BASIC_BLOCK (i + 1), EDGE_FALLTHRU);
1390 free_eh_nesting_info (eh_nest_info);
1392 sbitmap_vector_free (edge_cache);
1395 /* Create an edge between two basic blocks. FLAGS are auxiliary information
1396 about the edge that is accumulated between calls. */
1399 make_edge (edge_cache, src, dst, flags)
1400 sbitmap *edge_cache;
1401 basic_block src, dst;
1407 /* Don't bother with edge cache for ENTRY or EXIT; there aren't that
1408 many edges to them, and we didn't allocate memory for it. */
1409 use_edge_cache = (edge_cache
1410 && src != ENTRY_BLOCK_PTR
1411 && dst != EXIT_BLOCK_PTR);
1413 /* Make sure we don't add duplicate edges. */
1414 switch (use_edge_cache)
1417 /* Quick test for non-existance of the edge. */
1418 if (! TEST_BIT (edge_cache[src->index], dst->index))
1421 /* The edge exists; early exit if no work to do. */
1427 for (e = src->succ; e; e = e->succ_next)
1436 e = (edge) xcalloc (1, sizeof (*e));
1439 e->succ_next = src->succ;
1440 e->pred_next = dst->pred;
1449 SET_BIT (edge_cache[src->index], dst->index);
1452 /* Create an edge from a basic block to a label. */
1455 make_label_edge (edge_cache, src, label, flags)
1456 sbitmap *edge_cache;
1461 if (GET_CODE (label) != CODE_LABEL)
1464 /* If the label was never emitted, this insn is junk, but avoid a
1465 crash trying to refer to BLOCK_FOR_INSN (label). This can happen
1466 as a result of a syntax error and a diagnostic has already been
1469 if (INSN_UID (label) == 0)
1472 make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags);
1475 /* Create the edges generated by INSN in REGION. */
1478 make_eh_edge (edge_cache, eh_nest_info, src, insn, region)
1479 sbitmap *edge_cache;
1480 eh_nesting_info *eh_nest_info;
1485 handler_info **handler_list;
1488 is_call = (insn && GET_CODE (insn) == CALL_INSN ? EDGE_ABNORMAL_CALL : 0);
1489 num = reachable_handlers (region, eh_nest_info, insn, &handler_list);
1492 make_label_edge (edge_cache, src, handler_list[num]->handler_label,
1493 EDGE_ABNORMAL | EDGE_EH | is_call);
1497 /* EH_REGION notes appearing between basic blocks is ambiguous, and even
1498 dangerous if we intend to move basic blocks around. Move such notes
1499 into the following block. */
1502 move_stray_eh_region_notes ()
1507 if (n_basic_blocks < 2)
1510 b2 = BASIC_BLOCK (n_basic_blocks - 1);
1511 for (i = n_basic_blocks - 2; i >= 0; --i, b2 = b1)
1513 rtx insn, next, list = NULL_RTX;
1515 b1 = BASIC_BLOCK (i);
1516 for (insn = NEXT_INSN (b1->end); insn != b2->head; insn = next)
1518 next = NEXT_INSN (insn);
1519 if (GET_CODE (insn) == NOTE
1520 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG
1521 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
1523 /* Unlink from the insn chain. */
1524 NEXT_INSN (PREV_INSN (insn)) = next;
1525 PREV_INSN (next) = PREV_INSN (insn);
1528 NEXT_INSN (insn) = list;
1533 if (list == NULL_RTX)
1536 /* Find where to insert these things. */
1538 if (GET_CODE (insn) == CODE_LABEL)
1539 insn = NEXT_INSN (insn);
1543 next = NEXT_INSN (list);
1544 add_insn_after (list, insn);
1550 /* Recompute eh_beg/eh_end for each basic block. */
1553 record_active_eh_regions (f)
1556 rtx insn, eh_list = NULL_RTX;
1558 basic_block bb = BASIC_BLOCK (0);
1560 for (insn = f; insn; insn = NEXT_INSN (insn))
1562 if (bb->head == insn)
1563 bb->eh_beg = (eh_list ? NOTE_EH_HANDLER (XEXP (eh_list, 0)) : -1);
1565 if (GET_CODE (insn) == NOTE)
1567 int kind = NOTE_LINE_NUMBER (insn);
1568 if (kind == NOTE_INSN_EH_REGION_BEG)
1569 eh_list = alloc_INSN_LIST (insn, eh_list);
1570 else if (kind == NOTE_INSN_EH_REGION_END)
1572 rtx t = XEXP (eh_list, 1);
1573 free_INSN_LIST_node (eh_list);
1578 if (bb->end == insn)
1580 bb->eh_end = (eh_list ? NOTE_EH_HANDLER (XEXP (eh_list, 0)) : -1);
1582 if (i == n_basic_blocks)
1584 bb = BASIC_BLOCK (i);
1589 /* Identify critical edges and set the bits appropriately. */
1592 mark_critical_edges ()
1594 int i, n = n_basic_blocks;
1597 /* We begin with the entry block. This is not terribly important now,
1598 but could be if a front end (Fortran) implemented alternate entry
1600 bb = ENTRY_BLOCK_PTR;
1607 /* (1) Critical edges must have a source with multiple successors. */
1608 if (bb->succ && bb->succ->succ_next)
1610 for (e = bb->succ; e; e = e->succ_next)
1612 /* (2) Critical edges must have a destination with multiple
1613 predecessors. Note that we know there is at least one
1614 predecessor -- the edge we followed to get here. */
1615 if (e->dest->pred->pred_next)
1616 e->flags |= EDGE_CRITICAL;
1618 e->flags &= ~EDGE_CRITICAL;
1623 for (e = bb->succ; e; e = e->succ_next)
1624 e->flags &= ~EDGE_CRITICAL;
1629 bb = BASIC_BLOCK (i);
1633 /* Split a block BB after insn INSN creating a new fallthru edge.
1634 Return the new edge. Note that to keep other parts of the compiler happy,
1635 this function renumbers all the basic blocks so that the new
1636 one has a number one greater than the block split. */
1639 split_block (bb, insn)
1649 /* There is no point splitting the block after its end. */
1650 if (bb->end == insn)
1653 /* Create the new structures. */
1654 new_bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*new_bb));
1655 new_edge = (edge) xcalloc (1, sizeof (*new_edge));
1658 memset (new_bb, 0, sizeof (*new_bb));
1660 new_bb->head = NEXT_INSN (insn);
1661 new_bb->end = bb->end;
1664 new_bb->succ = bb->succ;
1665 bb->succ = new_edge;
1666 new_bb->pred = new_edge;
1667 new_bb->count = bb->count;
1668 new_bb->loop_depth = bb->loop_depth;
1671 new_edge->dest = new_bb;
1672 new_edge->flags = EDGE_FALLTHRU;
1673 new_edge->probability = REG_BR_PROB_BASE;
1674 new_edge->count = bb->count;
1676 /* Redirect the src of the successor edges of bb to point to new_bb. */
1677 for (e = new_bb->succ; e; e = e->succ_next)
1680 /* Place the new block just after the block being split. */
1681 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
1683 /* Some parts of the compiler expect blocks to be number in
1684 sequential order so insert the new block immediately after the
1685 block being split.. */
1687 for (i = n_basic_blocks - 1; i > j + 1; --i)
1689 basic_block tmp = BASIC_BLOCK (i - 1);
1690 BASIC_BLOCK (i) = tmp;
1694 BASIC_BLOCK (i) = new_bb;
1697 if (GET_CODE (new_bb->head) == CODE_LABEL)
1699 /* Create the basic block note. */
1700 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK,
1702 NOTE_BASIC_BLOCK (bb_note) = new_bb;
1706 /* Create the basic block note. */
1707 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
1709 NOTE_BASIC_BLOCK (bb_note) = new_bb;
1710 new_bb->head = bb_note;
1713 update_bb_for_insn (new_bb);
1715 if (bb->global_live_at_start)
1717 new_bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1718 new_bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1719 COPY_REG_SET (new_bb->global_live_at_end, bb->global_live_at_end);
1721 /* We now have to calculate which registers are live at the end
1722 of the split basic block and at the start of the new basic
1723 block. Start with those registers that are known to be live
1724 at the end of the original basic block and get
1725 propagate_block to determine which registers are live. */
1726 COPY_REG_SET (new_bb->global_live_at_start, bb->global_live_at_end);
1727 propagate_block (new_bb, new_bb->global_live_at_start, NULL, NULL, 0);
1728 COPY_REG_SET (bb->global_live_at_end,
1729 new_bb->global_live_at_start);
1736 /* Split a (typically critical) edge. Return the new block.
1737 Abort on abnormal edges.
1739 ??? The code generally expects to be called on critical edges.
1740 The case of a block ending in an unconditional jump to a
1741 block with multiple predecessors is not handled optimally. */
1744 split_edge (edge_in)
1747 basic_block old_pred, bb, old_succ;
1752 /* Abnormal edges cannot be split. */
1753 if ((edge_in->flags & EDGE_ABNORMAL) != 0)
1756 old_pred = edge_in->src;
1757 old_succ = edge_in->dest;
1759 /* Remove the existing edge from the destination's pred list. */
1762 for (pp = &old_succ->pred; *pp != edge_in; pp = &(*pp)->pred_next)
1764 *pp = edge_in->pred_next;
1765 edge_in->pred_next = NULL;
1768 /* Create the new structures. */
1769 bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*bb));
1770 edge_out = (edge) xcalloc (1, sizeof (*edge_out));
1773 memset (bb, 0, sizeof (*bb));
1775 /* ??? This info is likely going to be out of date very soon. */
1776 if (old_succ->global_live_at_start)
1778 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1779 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1780 COPY_REG_SET (bb->global_live_at_start, old_succ->global_live_at_start);
1781 COPY_REG_SET (bb->global_live_at_end, old_succ->global_live_at_start);
1786 bb->succ = edge_out;
1787 bb->count = edge_in->count;
1790 edge_in->flags &= ~EDGE_CRITICAL;
1792 edge_out->pred_next = old_succ->pred;
1793 edge_out->succ_next = NULL;
1795 edge_out->dest = old_succ;
1796 edge_out->flags = EDGE_FALLTHRU;
1797 edge_out->probability = REG_BR_PROB_BASE;
1798 edge_out->count = edge_in->count;
1800 old_succ->pred = edge_out;
1802 /* Tricky case -- if there existed a fallthru into the successor
1803 (and we're not it) we must add a new unconditional jump around
1804 the new block we're actually interested in.
1806 Further, if that edge is critical, this means a second new basic
1807 block must be created to hold it. In order to simplify correct
1808 insn placement, do this before we touch the existing basic block
1809 ordering for the block we were really wanting. */
1810 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1813 for (e = edge_out->pred_next; e; e = e->pred_next)
1814 if (e->flags & EDGE_FALLTHRU)
1819 basic_block jump_block;
1822 if ((e->flags & EDGE_CRITICAL) == 0
1823 && e->src != ENTRY_BLOCK_PTR)
1825 /* Non critical -- we can simply add a jump to the end
1826 of the existing predecessor. */
1827 jump_block = e->src;
1831 /* We need a new block to hold the jump. The simplest
1832 way to do the bulk of the work here is to recursively
1834 jump_block = split_edge (e);
1835 e = jump_block->succ;
1838 /* Now add the jump insn ... */
1839 pos = emit_jump_insn_after (gen_jump (old_succ->head),
1841 jump_block->end = pos;
1842 if (basic_block_for_insn)
1843 set_block_for_insn (pos, jump_block);
1844 emit_barrier_after (pos);
1846 /* ... let jump know that label is in use, ... */
1847 JUMP_LABEL (pos) = old_succ->head;
1848 ++LABEL_NUSES (old_succ->head);
1850 /* ... and clear fallthru on the outgoing edge. */
1851 e->flags &= ~EDGE_FALLTHRU;
1853 /* Continue splitting the interesting edge. */
1857 /* Place the new block just in front of the successor. */
1858 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
1859 if (old_succ == EXIT_BLOCK_PTR)
1860 j = n_basic_blocks - 1;
1862 j = old_succ->index;
1863 for (i = n_basic_blocks - 1; i > j; --i)
1865 basic_block tmp = BASIC_BLOCK (i - 1);
1866 BASIC_BLOCK (i) = tmp;
1869 BASIC_BLOCK (i) = bb;
1872 /* Create the basic block note.
1874 Where we place the note can have a noticable impact on the generated
1875 code. Consider this cfg:
1885 If we need to insert an insn on the edge from block 0 to block 1,
1886 we want to ensure the instructions we insert are outside of any
1887 loop notes that physically sit between block 0 and block 1. Otherwise
1888 we confuse the loop optimizer into thinking the loop is a phony. */
1889 if (old_succ != EXIT_BLOCK_PTR
1890 && PREV_INSN (old_succ->head)
1891 && GET_CODE (PREV_INSN (old_succ->head)) == NOTE
1892 && NOTE_LINE_NUMBER (PREV_INSN (old_succ->head)) == NOTE_INSN_LOOP_BEG)
1893 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
1894 PREV_INSN (old_succ->head));
1895 else if (old_succ != EXIT_BLOCK_PTR)
1896 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, old_succ->head);
1898 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
1899 NOTE_BASIC_BLOCK (bb_note) = bb;
1900 bb->head = bb->end = bb_note;
1902 /* Not quite simple -- for non-fallthru edges, we must adjust the
1903 predecessor's jump instruction to target our new block. */
1904 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1906 rtx tmp, insn = old_pred->end;
1907 rtx old_label = old_succ->head;
1908 rtx new_label = gen_label_rtx ();
1910 if (GET_CODE (insn) != JUMP_INSN)
1913 /* ??? Recognize a tablejump and adjust all matching cases. */
1914 if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1915 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1916 && GET_CODE (tmp) == JUMP_INSN
1917 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1918 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1923 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1924 vec = XVEC (PATTERN (tmp), 0);
1926 vec = XVEC (PATTERN (tmp), 1);
1928 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1929 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
1931 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (VOIDmode, new_label);
1932 --LABEL_NUSES (old_label);
1933 ++LABEL_NUSES (new_label);
1936 /* Handle casesi dispatch insns */
1937 if ((tmp = single_set (insn)) != NULL
1938 && SET_DEST (tmp) == pc_rtx
1939 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1940 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
1941 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
1943 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (VOIDmode,
1945 --LABEL_NUSES (old_label);
1946 ++LABEL_NUSES (new_label);
1951 /* This would have indicated an abnormal edge. */
1952 if (computed_jump_p (insn))
1955 /* A return instruction can't be redirected. */
1956 if (returnjump_p (insn))
1959 /* If the insn doesn't go where we think, we're confused. */
1960 if (JUMP_LABEL (insn) != old_label)
1963 redirect_jump (insn, new_label, 0);
1966 emit_label_before (new_label, bb_note);
1967 bb->head = new_label;
1973 /* Queue instructions for insertion on an edge between two basic blocks.
1974 The new instructions and basic blocks (if any) will not appear in the
1975 CFG until commit_edge_insertions is called. */
1978 insert_insn_on_edge (pattern, e)
1982 /* We cannot insert instructions on an abnormal critical edge.
1983 It will be easier to find the culprit if we die now. */
1984 if ((e->flags & (EDGE_ABNORMAL|EDGE_CRITICAL))
1985 == (EDGE_ABNORMAL|EDGE_CRITICAL))
1988 if (e->insns == NULL_RTX)
1991 push_to_sequence (e->insns);
1993 emit_insn (pattern);
1995 e->insns = get_insns ();
1999 /* Update the CFG for the instructions queued on edge E. */
2002 commit_one_edge_insertion (e)
2005 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
2008 /* Pull the insns off the edge now since the edge might go away. */
2010 e->insns = NULL_RTX;
2012 /* Figure out where to put these things. If the destination has
2013 one predecessor, insert there. Except for the exit block. */
2014 if (e->dest->pred->pred_next == NULL
2015 && e->dest != EXIT_BLOCK_PTR)
2019 /* Get the location correct wrt a code label, and "nice" wrt
2020 a basic block note, and before everything else. */
2022 if (GET_CODE (tmp) == CODE_LABEL)
2023 tmp = NEXT_INSN (tmp);
2024 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
2025 tmp = NEXT_INSN (tmp);
2026 if (tmp == bb->head)
2029 after = PREV_INSN (tmp);
2032 /* If the source has one successor and the edge is not abnormal,
2033 insert there. Except for the entry block. */
2034 else if ((e->flags & EDGE_ABNORMAL) == 0
2035 && e->src->succ->succ_next == NULL
2036 && e->src != ENTRY_BLOCK_PTR)
2039 /* It is possible to have a non-simple jump here. Consider a target
2040 where some forms of unconditional jumps clobber a register. This
2041 happens on the fr30 for example.
2043 We know this block has a single successor, so we can just emit
2044 the queued insns before the jump. */
2045 if (GET_CODE (bb->end) == JUMP_INSN)
2051 /* We'd better be fallthru, or we've lost track of what's what. */
2052 if ((e->flags & EDGE_FALLTHRU) == 0)
2059 /* Otherwise we must split the edge. */
2062 bb = split_edge (e);
2066 /* Now that we've found the spot, do the insertion. */
2068 /* Set the new block number for these insns, if structure is allocated. */
2069 if (basic_block_for_insn)
2072 for (i = insns; i != NULL_RTX; i = NEXT_INSN (i))
2073 set_block_for_insn (i, bb);
2078 emit_insns_before (insns, before);
2079 if (before == bb->head)
2082 last = prev_nonnote_insn (before);
2086 last = emit_insns_after (insns, after);
2087 if (after == bb->end)
2091 if (returnjump_p (last))
2093 /* ??? Remove all outgoing edges from BB and add one for EXIT.
2094 This is not currently a problem because this only happens
2095 for the (single) epilogue, which already has a fallthru edge
2099 if (e->dest != EXIT_BLOCK_PTR
2100 || e->succ_next != NULL
2101 || (e->flags & EDGE_FALLTHRU) == 0)
2103 e->flags &= ~EDGE_FALLTHRU;
2105 emit_barrier_after (last);
2109 flow_delete_insn (before);
2111 else if (GET_CODE (last) == JUMP_INSN)
2113 find_sub_basic_blocks (bb);
2116 /* Update the CFG for all queued instructions. */
2119 commit_edge_insertions ()
2124 #ifdef ENABLE_CHECKING
2125 verify_flow_info ();
2129 bb = ENTRY_BLOCK_PTR;
2134 for (e = bb->succ; e; e = next)
2136 next = e->succ_next;
2138 commit_one_edge_insertion (e);
2141 if (++i >= n_basic_blocks)
2143 bb = BASIC_BLOCK (i);
2147 /* Add fake edges to the function exit for any non constant calls in
2148 the bitmap of blocks specified by BLOCKS or to the whole CFG if
2149 BLOCKS is zero. Return the nuber of blocks that were split. */
2152 flow_call_edges_add (blocks)
2156 int blocks_split = 0;
2160 /* Map bb indicies into basic block pointers since split_block
2161 will renumber the basic blocks. */
2163 bbs = xmalloc (n_basic_blocks * sizeof (*bbs));
2167 for (i = 0; i < n_basic_blocks; i++)
2168 bbs[bb_num++] = BASIC_BLOCK (i);
2172 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
2174 bbs[bb_num++] = BASIC_BLOCK (i);
2179 /* Now add fake edges to the function exit for any non constant
2180 calls since there is no way that we can determine if they will
2183 for (i = 0; i < bb_num; i++)
2185 basic_block bb = bbs[i];
2189 for (insn = bb->end; ; insn = prev_insn)
2191 prev_insn = PREV_INSN (insn);
2192 if (GET_CODE (insn) == CALL_INSN && ! CONST_CALL_P (insn))
2196 /* Note that the following may create a new basic block
2197 and renumber the existing basic blocks. */
2198 e = split_block (bb, insn);
2202 make_edge (NULL, bb, EXIT_BLOCK_PTR, EDGE_FAKE);
2204 if (insn == bb->head)
2210 verify_flow_info ();
2213 return blocks_split;
2216 /* Delete all unreachable basic blocks. */
2219 delete_unreachable_blocks ()
2221 basic_block *worklist, *tos;
2222 int deleted_handler;
2227 tos = worklist = (basic_block *) xmalloc (sizeof (basic_block) * n);
2229 /* Use basic_block->aux as a marker. Clear them all. */
2231 for (i = 0; i < n; ++i)
2232 BASIC_BLOCK (i)->aux = NULL;
2234 /* Add our starting points to the worklist. Almost always there will
2235 be only one. It isn't inconcievable that we might one day directly
2236 support Fortran alternate entry points. */
2238 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
2242 /* Mark the block with a handy non-null value. */
2246 /* Iterate: find everything reachable from what we've already seen. */
2248 while (tos != worklist)
2250 basic_block b = *--tos;
2252 for (e = b->succ; e; e = e->succ_next)
2260 /* Delete all unreachable basic blocks. Count down so that we don't
2261 interfere with the block renumbering that happens in flow_delete_block. */
2263 deleted_handler = 0;
2265 for (i = n - 1; i >= 0; --i)
2267 basic_block b = BASIC_BLOCK (i);
2270 /* This block was found. Tidy up the mark. */
2273 deleted_handler |= flow_delete_block (b);
2276 tidy_fallthru_edges ();
2278 /* If we deleted an exception handler, we may have EH region begin/end
2279 blocks to remove as well. */
2280 if (deleted_handler)
2281 delete_eh_regions ();
2286 /* Find EH regions for which there is no longer a handler, and delete them. */
2289 delete_eh_regions ()
2293 update_rethrow_references ();
2295 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
2296 if (GET_CODE (insn) == NOTE)
2298 if ((NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
2299 || (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
2301 int num = NOTE_EH_HANDLER (insn);
2302 /* A NULL handler indicates a region is no longer needed,
2303 as long as its rethrow label isn't used. */
2304 if (get_first_handler (num) == NULL && ! rethrow_used (num))
2306 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
2307 NOTE_SOURCE_FILE (insn) = 0;
2313 /* Return true if NOTE is not one of the ones that must be kept paired,
2314 so that we may simply delete them. */
2317 can_delete_note_p (note)
2320 return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED
2321 || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK);
2324 /* Unlink a chain of insns between START and FINISH, leaving notes
2325 that must be paired. */
2328 flow_delete_insn_chain (start, finish)
2331 /* Unchain the insns one by one. It would be quicker to delete all
2332 of these with a single unchaining, rather than one at a time, but
2333 we need to keep the NOTE's. */
2339 next = NEXT_INSN (start);
2340 if (GET_CODE (start) == NOTE && !can_delete_note_p (start))
2342 else if (GET_CODE (start) == CODE_LABEL
2343 && ! can_delete_label_p (start))
2345 const char *name = LABEL_NAME (start);
2346 PUT_CODE (start, NOTE);
2347 NOTE_LINE_NUMBER (start) = NOTE_INSN_DELETED_LABEL;
2348 NOTE_SOURCE_FILE (start) = name;
2351 next = flow_delete_insn (start);
2353 if (start == finish)
2359 /* Delete the insns in a (non-live) block. We physically delete every
2360 non-deleted-note insn, and update the flow graph appropriately.
2362 Return nonzero if we deleted an exception handler. */
2364 /* ??? Preserving all such notes strikes me as wrong. It would be nice
2365 to post-process the stream to remove empty blocks, loops, ranges, etc. */
2368 flow_delete_block (b)
2371 int deleted_handler = 0;
2374 /* If the head of this block is a CODE_LABEL, then it might be the
2375 label for an exception handler which can't be reached.
2377 We need to remove the label from the exception_handler_label list
2378 and remove the associated NOTE_INSN_EH_REGION_BEG and
2379 NOTE_INSN_EH_REGION_END notes. */
2383 never_reached_warning (insn);
2385 if (GET_CODE (insn) == CODE_LABEL)
2387 rtx x, *prev = &exception_handler_labels;
2389 for (x = exception_handler_labels; x; x = XEXP (x, 1))
2391 if (XEXP (x, 0) == insn)
2393 /* Found a match, splice this label out of the EH label list. */
2394 *prev = XEXP (x, 1);
2395 XEXP (x, 1) = NULL_RTX;
2396 XEXP (x, 0) = NULL_RTX;
2398 /* Remove the handler from all regions */
2399 remove_handler (insn);
2400 deleted_handler = 1;
2403 prev = &XEXP (x, 1);
2407 /* Include any jump table following the basic block. */
2409 if (GET_CODE (end) == JUMP_INSN
2410 && (tmp = JUMP_LABEL (end)) != NULL_RTX
2411 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
2412 && GET_CODE (tmp) == JUMP_INSN
2413 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
2414 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
2417 /* Include any barrier that may follow the basic block. */
2418 tmp = next_nonnote_insn (end);
2419 if (tmp && GET_CODE (tmp) == BARRIER)
2422 /* Selectively delete the entire chain. */
2423 flow_delete_insn_chain (insn, end);
2425 /* Remove the edges into and out of this block. Note that there may
2426 indeed be edges in, if we are removing an unreachable loop. */
2430 for (e = b->pred; e; e = next)
2432 for (q = &e->src->succ; *q != e; q = &(*q)->succ_next)
2435 next = e->pred_next;
2439 for (e = b->succ; e; e = next)
2441 for (q = &e->dest->pred; *q != e; q = &(*q)->pred_next)
2444 next = e->succ_next;
2453 /* Remove the basic block from the array, and compact behind it. */
2456 return deleted_handler;
2459 /* Remove block B from the basic block array and compact behind it. */
2465 int i, n = n_basic_blocks;
2467 for (i = b->index; i + 1 < n; ++i)
2469 basic_block x = BASIC_BLOCK (i + 1);
2470 BASIC_BLOCK (i) = x;
2474 basic_block_info->num_elements--;
2478 /* Delete INSN by patching it out. Return the next insn. */
2481 flow_delete_insn (insn)
2484 rtx prev = PREV_INSN (insn);
2485 rtx next = NEXT_INSN (insn);
2488 PREV_INSN (insn) = NULL_RTX;
2489 NEXT_INSN (insn) = NULL_RTX;
2490 INSN_DELETED_P (insn) = 1;
2493 NEXT_INSN (prev) = next;
2495 PREV_INSN (next) = prev;
2497 set_last_insn (prev);
2499 if (GET_CODE (insn) == CODE_LABEL)
2500 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2502 /* If deleting a jump, decrement the use count of the label. Deleting
2503 the label itself should happen in the normal course of block merging. */
2504 if (GET_CODE (insn) == JUMP_INSN
2505 && JUMP_LABEL (insn)
2506 && GET_CODE (JUMP_LABEL (insn)) == CODE_LABEL)
2507 LABEL_NUSES (JUMP_LABEL (insn))--;
2509 /* Also if deleting an insn that references a label. */
2510 else if ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX
2511 && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
2512 LABEL_NUSES (XEXP (note, 0))--;
2517 /* True if a given label can be deleted. */
2520 can_delete_label_p (label)
2525 if (LABEL_PRESERVE_P (label))
2528 for (x = forced_labels; x; x = XEXP (x, 1))
2529 if (label == XEXP (x, 0))
2531 for (x = label_value_list; x; x = XEXP (x, 1))
2532 if (label == XEXP (x, 0))
2534 for (x = exception_handler_labels; x; x = XEXP (x, 1))
2535 if (label == XEXP (x, 0))
2538 /* User declared labels must be preserved. */
2539 if (LABEL_NAME (label) != 0)
2546 tail_recursion_label_p (label)
2551 for (x = tail_recursion_label_list; x; x = XEXP (x, 1))
2552 if (label == XEXP (x, 0))
2558 /* Blocks A and B are to be merged into a single block A. The insns
2559 are already contiguous, hence `nomove'. */
2562 merge_blocks_nomove (a, b)
2566 rtx b_head, b_end, a_end;
2567 rtx del_first = NULL_RTX, del_last = NULL_RTX;
2570 /* If there was a CODE_LABEL beginning B, delete it. */
2573 if (GET_CODE (b_head) == CODE_LABEL)
2575 /* Detect basic blocks with nothing but a label. This can happen
2576 in particular at the end of a function. */
2577 if (b_head == b_end)
2579 del_first = del_last = b_head;
2580 b_head = NEXT_INSN (b_head);
2583 /* Delete the basic block note. */
2584 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
2586 if (b_head == b_end)
2591 b_head = NEXT_INSN (b_head);
2594 /* If there was a jump out of A, delete it. */
2596 if (GET_CODE (a_end) == JUMP_INSN)
2600 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
2601 if (GET_CODE (prev) != NOTE
2602 || NOTE_LINE_NUMBER (prev) == NOTE_INSN_BASIC_BLOCK
2609 /* If this was a conditional jump, we need to also delete
2610 the insn that set cc0. */
2611 if (prev && sets_cc0_p (prev))
2614 prev = prev_nonnote_insn (prev);
2623 else if (GET_CODE (NEXT_INSN (a_end)) == BARRIER)
2624 del_first = NEXT_INSN (a_end);
2626 /* Delete everything marked above as well as crap that might be
2627 hanging out between the two blocks. */
2628 flow_delete_insn_chain (del_first, del_last);
2630 /* Normally there should only be one successor of A and that is B, but
2631 partway though the merge of blocks for conditional_execution we'll
2632 be merging a TEST block with THEN and ELSE successors. Free the
2633 whole lot of them and hope the caller knows what they're doing. */
2635 remove_edge (a->succ);
2637 /* Adjust the edges out of B for the new owner. */
2638 for (e = b->succ; e; e = e->succ_next)
2642 /* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */
2643 b->pred = b->succ = NULL;
2645 /* Reassociate the insns of B with A. */
2648 if (basic_block_for_insn)
2650 BLOCK_FOR_INSN (b_head) = a;
2651 while (b_head != b_end)
2653 b_head = NEXT_INSN (b_head);
2654 BLOCK_FOR_INSN (b_head) = a;
2664 /* Blocks A and B are to be merged into a single block. A has no incoming
2665 fallthru edge, so it can be moved before B without adding or modifying
2666 any jumps (aside from the jump from A to B). */
2669 merge_blocks_move_predecessor_nojumps (a, b)
2672 rtx start, end, barrier;
2678 barrier = next_nonnote_insn (end);
2679 if (GET_CODE (barrier) != BARRIER)
2681 flow_delete_insn (barrier);
2683 /* Move block and loop notes out of the chain so that we do not
2684 disturb their order.
2686 ??? A better solution would be to squeeze out all the non-nested notes
2687 and adjust the block trees appropriately. Even better would be to have
2688 a tighter connection between block trees and rtl so that this is not
2690 start = squeeze_notes (start, end);
2692 /* Scramble the insn chain. */
2693 if (end != PREV_INSN (b->head))
2694 reorder_insns (start, end, PREV_INSN (b->head));
2698 fprintf (rtl_dump_file, "Moved block %d before %d and merged.\n",
2699 a->index, b->index);
2702 /* Swap the records for the two blocks around. Although we are deleting B,
2703 A is now where B was and we want to compact the BB array from where
2705 BASIC_BLOCK (a->index) = b;
2706 BASIC_BLOCK (b->index) = a;
2708 a->index = b->index;
2711 /* Now blocks A and B are contiguous. Merge them. */
2712 merge_blocks_nomove (a, b);
2717 /* Blocks A and B are to be merged into a single block. B has no outgoing
2718 fallthru edge, so it can be moved after A without adding or modifying
2719 any jumps (aside from the jump from A to B). */
2722 merge_blocks_move_successor_nojumps (a, b)
2725 rtx start, end, barrier;
2729 barrier = NEXT_INSN (end);
2731 /* Recognize a jump table following block B. */
2732 if (GET_CODE (barrier) == CODE_LABEL
2733 && NEXT_INSN (barrier)
2734 && GET_CODE (NEXT_INSN (barrier)) == JUMP_INSN
2735 && (GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_VEC
2736 || GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_DIFF_VEC))
2738 end = NEXT_INSN (barrier);
2739 barrier = NEXT_INSN (end);
2742 /* There had better have been a barrier there. Delete it. */
2743 if (GET_CODE (barrier) != BARRIER)
2745 flow_delete_insn (barrier);
2747 /* Move block and loop notes out of the chain so that we do not
2748 disturb their order.
2750 ??? A better solution would be to squeeze out all the non-nested notes
2751 and adjust the block trees appropriately. Even better would be to have
2752 a tighter connection between block trees and rtl so that this is not
2754 start = squeeze_notes (start, end);
2756 /* Scramble the insn chain. */
2757 reorder_insns (start, end, a->end);
2759 /* Now blocks A and B are contiguous. Merge them. */
2760 merge_blocks_nomove (a, b);
2764 fprintf (rtl_dump_file, "Moved block %d after %d and merged.\n",
2765 b->index, a->index);
2771 /* Attempt to merge basic blocks that are potentially non-adjacent.
2772 Return true iff the attempt succeeded. */
2775 merge_blocks (e, b, c)
2779 /* If C has a tail recursion label, do not merge. There is no
2780 edge recorded from the call_placeholder back to this label, as
2781 that would make optimize_sibling_and_tail_recursive_calls more
2782 complex for no gain. */
2783 if (GET_CODE (c->head) == CODE_LABEL
2784 && tail_recursion_label_p (c->head))
2787 /* If B has a fallthru edge to C, no need to move anything. */
2788 if (e->flags & EDGE_FALLTHRU)
2790 merge_blocks_nomove (b, c);
2794 fprintf (rtl_dump_file, "Merged %d and %d without moving.\n",
2795 b->index, c->index);
2804 int c_has_outgoing_fallthru;
2805 int b_has_incoming_fallthru;
2807 /* We must make sure to not munge nesting of exception regions,
2808 lexical blocks, and loop notes.
2810 The first is taken care of by requiring that the active eh
2811 region at the end of one block always matches the active eh
2812 region at the beginning of the next block.
2814 The later two are taken care of by squeezing out all the notes. */
2816 /* ??? A throw/catch edge (or any abnormal edge) should be rarely
2817 executed and we may want to treat blocks which have two out
2818 edges, one normal, one abnormal as only having one edge for
2819 block merging purposes. */
2821 for (tmp_edge = c->succ; tmp_edge; tmp_edge = tmp_edge->succ_next)
2822 if (tmp_edge->flags & EDGE_FALLTHRU)
2824 c_has_outgoing_fallthru = (tmp_edge != NULL);
2826 for (tmp_edge = b->pred; tmp_edge; tmp_edge = tmp_edge->pred_next)
2827 if (tmp_edge->flags & EDGE_FALLTHRU)
2829 b_has_incoming_fallthru = (tmp_edge != NULL);
2831 /* If B does not have an incoming fallthru, and the exception regions
2832 match, then it can be moved immediately before C without introducing
2835 C can not be the first block, so we do not have to worry about
2836 accessing a non-existent block. */
2837 d = BASIC_BLOCK (c->index - 1);
2838 if (! b_has_incoming_fallthru
2839 && d->eh_end == b->eh_beg
2840 && b->eh_end == c->eh_beg)
2841 return merge_blocks_move_predecessor_nojumps (b, c);
2843 /* Otherwise, we're going to try to move C after B. Make sure the
2844 exception regions match.
2846 If B is the last basic block, then we must not try to access the
2847 block structure for block B + 1. Luckily in that case we do not
2848 need to worry about matching exception regions. */
2849 d = (b->index + 1 < n_basic_blocks ? BASIC_BLOCK (b->index + 1) : NULL);
2850 if (b->eh_end == c->eh_beg
2851 && (d == NULL || c->eh_end == d->eh_beg))
2853 /* If C does not have an outgoing fallthru, then it can be moved
2854 immediately after B without introducing or modifying jumps. */
2855 if (! c_has_outgoing_fallthru)
2856 return merge_blocks_move_successor_nojumps (b, c);
2858 /* Otherwise, we'll need to insert an extra jump, and possibly
2859 a new block to contain it. */
2860 /* ??? Not implemented yet. */
2867 /* Top level driver for merge_blocks. */
2874 /* Attempt to merge blocks as made possible by edge removal. If a block
2875 has only one successor, and the successor has only one predecessor,
2876 they may be combined. */
2878 for (i = 0; i < n_basic_blocks;)
2880 basic_block c, b = BASIC_BLOCK (i);
2883 /* A loop because chains of blocks might be combineable. */
2884 while ((s = b->succ) != NULL
2885 && s->succ_next == NULL
2886 && (s->flags & EDGE_EH) == 0
2887 && (c = s->dest) != EXIT_BLOCK_PTR
2888 && c->pred->pred_next == NULL
2889 /* If the jump insn has side effects, we can't kill the edge. */
2890 && (GET_CODE (b->end) != JUMP_INSN
2891 || onlyjump_p (b->end))
2892 && merge_blocks (s, b, c))
2895 /* Don't get confused by the index shift caused by deleting blocks. */
2900 /* The given edge should potentially be a fallthru edge. If that is in
2901 fact true, delete the jump and barriers that are in the way. */
2904 tidy_fallthru_edge (e, b, c)
2910 /* ??? In a late-running flow pass, other folks may have deleted basic
2911 blocks by nopping out blocks, leaving multiple BARRIERs between here
2912 and the target label. They ought to be chastized and fixed.
2914 We can also wind up with a sequence of undeletable labels between
2915 one block and the next.
2917 So search through a sequence of barriers, labels, and notes for
2918 the head of block C and assert that we really do fall through. */
2920 if (next_real_insn (b->end) != next_real_insn (PREV_INSN (c->head)))
2923 /* Remove what will soon cease being the jump insn from the source block.
2924 If block B consisted only of this single jump, turn it into a deleted
2927 if (GET_CODE (q) == JUMP_INSN
2929 && (any_uncondjump_p (q)
2930 || (b->succ == e && e->succ_next == NULL)))
2933 /* If this was a conditional jump, we need to also delete
2934 the insn that set cc0. */
2935 if (any_condjump_p (q) && sets_cc0_p (PREV_INSN (q)))
2942 NOTE_LINE_NUMBER (q) = NOTE_INSN_DELETED;
2943 NOTE_SOURCE_FILE (q) = 0;
2949 /* We don't want a block to end on a line-number note since that has
2950 the potential of changing the code between -g and not -g. */
2951 while (GET_CODE (q) == NOTE && NOTE_LINE_NUMBER (q) >= 0)
2958 /* Selectively unlink the sequence. */
2959 if (q != PREV_INSN (c->head))
2960 flow_delete_insn_chain (NEXT_INSN (q), PREV_INSN (c->head));
2962 e->flags |= EDGE_FALLTHRU;
2965 /* Fix up edges that now fall through, or rather should now fall through
2966 but previously required a jump around now deleted blocks. Simplify
2967 the search by only examining blocks numerically adjacent, since this
2968 is how find_basic_blocks created them. */
2971 tidy_fallthru_edges ()
2975 for (i = 1; i < n_basic_blocks; ++i)
2977 basic_block b = BASIC_BLOCK (i - 1);
2978 basic_block c = BASIC_BLOCK (i);
2981 /* We care about simple conditional or unconditional jumps with
2984 If we had a conditional branch to the next instruction when
2985 find_basic_blocks was called, then there will only be one
2986 out edge for the block which ended with the conditional
2987 branch (since we do not create duplicate edges).
2989 Furthermore, the edge will be marked as a fallthru because we
2990 merge the flags for the duplicate edges. So we do not want to
2991 check that the edge is not a FALLTHRU edge. */
2992 if ((s = b->succ) != NULL
2993 && s->succ_next == NULL
2995 /* If the jump insn has side effects, we can't tidy the edge. */
2996 && (GET_CODE (b->end) != JUMP_INSN
2997 || onlyjump_p (b->end)))
2998 tidy_fallthru_edge (s, b, c);
3002 /* Perform data flow analysis.
3003 F is the first insn of the function; FLAGS is a set of PROP_* flags
3004 to be used in accumulating flow info. */
3007 life_analysis (f, file, flags)
3012 #ifdef ELIMINABLE_REGS
3014 static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
3017 /* Record which registers will be eliminated. We use this in
3020 CLEAR_HARD_REG_SET (elim_reg_set);
3022 #ifdef ELIMINABLE_REGS
3023 for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
3024 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
3026 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
3030 flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC);
3032 /* The post-reload life analysis have (on a global basis) the same
3033 registers live as was computed by reload itself. elimination
3034 Otherwise offsets and such may be incorrect.
3036 Reload will make some registers as live even though they do not
3039 We don't want to create new auto-incs after reload, since they
3040 are unlikely to be useful and can cause problems with shared
3042 if (reload_completed)
3043 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
3045 /* We want alias analysis information for local dead store elimination. */
3046 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
3047 init_alias_analysis ();
3049 /* Always remove no-op moves. Do this before other processing so
3050 that we don't have to keep re-scanning them. */
3051 delete_noop_moves (f);
3053 /* Some targets can emit simpler epilogues if they know that sp was
3054 not ever modified during the function. After reload, of course,
3055 we've already emitted the epilogue so there's no sense searching. */
3056 if (! reload_completed)
3057 notice_stack_pointer_modification (f);
3059 /* Allocate and zero out data structures that will record the
3060 data from lifetime analysis. */
3061 allocate_reg_life_data ();
3062 allocate_bb_life_data ();
3064 /* Find the set of registers live on function exit. */
3065 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
3067 /* "Update" life info from zero. It'd be nice to begin the
3068 relaxation with just the exit and noreturn blocks, but that set
3069 is not immediately handy. */
3071 if (flags & PROP_REG_INFO)
3072 memset (regs_ever_live, 0, sizeof (regs_ever_live));
3073 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
3076 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
3077 end_alias_analysis ();
3080 dump_flow_info (file);
3082 free_basic_block_vars (1);
3085 /* A subroutine of verify_wide_reg, called through for_each_rtx.
3086 Search for REGNO. If found, abort if it is not wider than word_mode. */
3089 verify_wide_reg_1 (px, pregno)
3094 unsigned int regno = *(int *) pregno;
3096 if (GET_CODE (x) == REG && REGNO (x) == regno)
3098 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
3105 /* A subroutine of verify_local_live_at_start. Search through insns
3106 between HEAD and END looking for register REGNO. */
3109 verify_wide_reg (regno, head, end)
3116 && for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no))
3120 head = NEXT_INSN (head);
3123 /* We didn't find the register at all. Something's way screwy. */
3125 fprintf (rtl_dump_file, "Aborting in verify_wide_reg; reg %d\n", regno);
3126 print_rtl_and_abort ();
3129 /* A subroutine of update_life_info. Verify that there are no untoward
3130 changes in live_at_start during a local update. */
3133 verify_local_live_at_start (new_live_at_start, bb)
3134 regset new_live_at_start;
3137 if (reload_completed)
3139 /* After reload, there are no pseudos, nor subregs of multi-word
3140 registers. The regsets should exactly match. */
3141 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
3145 fprintf (rtl_dump_file,
3146 "live_at_start mismatch in bb %d, aborting\n",
3148 debug_bitmap_file (rtl_dump_file, bb->global_live_at_start);
3149 debug_bitmap_file (rtl_dump_file, new_live_at_start);
3151 print_rtl_and_abort ();
3158 /* Find the set of changed registers. */
3159 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
3161 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
3163 /* No registers should die. */
3164 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
3167 fprintf (rtl_dump_file,
3168 "Register %d died unexpectedly in block %d\n", i,
3170 print_rtl_and_abort ();
3173 /* Verify that the now-live register is wider than word_mode. */
3174 verify_wide_reg (i, bb->head, bb->end);
3179 /* Updates life information starting with the basic blocks set in BLOCKS.
3180 If BLOCKS is null, consider it to be the universal set.
3182 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
3183 we are only expecting local modifications to basic blocks. If we find
3184 extra registers live at the beginning of a block, then we either killed
3185 useful data, or we have a broken split that wants data not provided.
3186 If we find registers removed from live_at_start, that means we have
3187 a broken peephole that is killing a register it shouldn't.
3189 ??? This is not true in one situation -- when a pre-reload splitter
3190 generates subregs of a multi-word pseudo, current life analysis will
3191 lose the kill. So we _can_ have a pseudo go live. How irritating.
3193 Including PROP_REG_INFO does not properly refresh regs_ever_live
3194 unless the caller resets it to zero. */
3197 update_life_info (blocks, extent, prop_flags)
3199 enum update_life_extent extent;
3203 regset_head tmp_head;
3206 tmp = INITIALIZE_REG_SET (tmp_head);
3208 /* For a global update, we go through the relaxation process again. */
3209 if (extent != UPDATE_LIFE_LOCAL)
3211 calculate_global_regs_live (blocks, blocks,
3212 prop_flags & PROP_SCAN_DEAD_CODE);
3214 /* If asked, remove notes from the blocks we'll update. */
3215 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
3216 count_or_remove_death_notes (blocks, 1);
3221 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
3223 basic_block bb = BASIC_BLOCK (i);
3225 COPY_REG_SET (tmp, bb->global_live_at_end);
3226 propagate_block (bb, tmp, NULL, NULL, prop_flags);
3228 if (extent == UPDATE_LIFE_LOCAL)
3229 verify_local_live_at_start (tmp, bb);
3234 for (i = n_basic_blocks - 1; i >= 0; --i)
3236 basic_block bb = BASIC_BLOCK (i);
3238 COPY_REG_SET (tmp, bb->global_live_at_end);
3239 propagate_block (bb, tmp, NULL, NULL, prop_flags);
3241 if (extent == UPDATE_LIFE_LOCAL)
3242 verify_local_live_at_start (tmp, bb);
3248 if (prop_flags & PROP_REG_INFO)
3250 /* The only pseudos that are live at the beginning of the function
3251 are those that were not set anywhere in the function. local-alloc
3252 doesn't know how to handle these correctly, so mark them as not
3253 local to any one basic block. */
3254 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
3255 FIRST_PSEUDO_REGISTER, i,
3256 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
3258 /* We have a problem with any pseudoreg that lives across the setjmp.
3259 ANSI says that if a user variable does not change in value between
3260 the setjmp and the longjmp, then the longjmp preserves it. This
3261 includes longjmp from a place where the pseudo appears dead.
3262 (In principle, the value still exists if it is in scope.)
3263 If the pseudo goes in a hard reg, some other value may occupy
3264 that hard reg where this pseudo is dead, thus clobbering the pseudo.
3265 Conclusion: such a pseudo must not go in a hard reg. */
3266 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
3267 FIRST_PSEUDO_REGISTER, i,
3269 if (regno_reg_rtx[i] != 0)
3271 REG_LIVE_LENGTH (i) = -1;
3272 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
3278 /* Free the variables allocated by find_basic_blocks.
3280 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
3283 free_basic_block_vars (keep_head_end_p)
3284 int keep_head_end_p;
3286 if (basic_block_for_insn)
3288 VARRAY_FREE (basic_block_for_insn);
3289 basic_block_for_insn = NULL;
3292 if (! keep_head_end_p)
3295 VARRAY_FREE (basic_block_info);
3298 ENTRY_BLOCK_PTR->aux = NULL;
3299 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
3300 EXIT_BLOCK_PTR->aux = NULL;
3301 EXIT_BLOCK_PTR->global_live_at_start = NULL;
3305 /* Return nonzero if the destination of SET equals the source. */
3311 rtx src = SET_SRC (set);
3312 rtx dst = SET_DEST (set);
3314 if (GET_CODE (src) == SUBREG && GET_CODE (dst) == SUBREG)
3316 if (SUBREG_WORD (src) != SUBREG_WORD (dst))
3318 src = SUBREG_REG (src);
3319 dst = SUBREG_REG (dst);
3322 return (GET_CODE (src) == REG && GET_CODE (dst) == REG
3323 && REGNO (src) == REGNO (dst));
3326 /* Return nonzero if an insn consists only of SETs, each of which only sets a
3333 rtx pat = PATTERN (insn);
3335 /* Insns carrying these notes are useful later on. */
3336 if (find_reg_note (insn, REG_EQUAL, NULL_RTX))
3339 if (GET_CODE (pat) == SET && set_noop_p (pat))
3342 if (GET_CODE (pat) == PARALLEL)
3345 /* If nothing but SETs of registers to themselves,
3346 this insn can also be deleted. */
3347 for (i = 0; i < XVECLEN (pat, 0); i++)
3349 rtx tem = XVECEXP (pat, 0, i);
3351 if (GET_CODE (tem) == USE
3352 || GET_CODE (tem) == CLOBBER)
3355 if (GET_CODE (tem) != SET || ! set_noop_p (tem))
3364 /* Delete any insns that copy a register to itself. */
3367 delete_noop_moves (f)
3371 for (insn = f; insn; insn = NEXT_INSN (insn))
3373 if (GET_CODE (insn) == INSN && noop_move_p (insn))
3375 PUT_CODE (insn, NOTE);
3376 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
3377 NOTE_SOURCE_FILE (insn) = 0;
3382 /* Determine if the stack pointer is constant over the life of the function.
3383 Only useful before prologues have been emitted. */
3386 notice_stack_pointer_modification_1 (x, pat, data)
3388 rtx pat ATTRIBUTE_UNUSED;
3389 void *data ATTRIBUTE_UNUSED;
3391 if (x == stack_pointer_rtx
3392 /* The stack pointer is only modified indirectly as the result
3393 of a push until later in flow. See the comments in rtl.texi
3394 regarding Embedded Side-Effects on Addresses. */
3395 || (GET_CODE (x) == MEM
3396 && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
3397 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
3398 current_function_sp_is_unchanging = 0;
3402 notice_stack_pointer_modification (f)
3407 /* Assume that the stack pointer is unchanging if alloca hasn't
3409 current_function_sp_is_unchanging = !current_function_calls_alloca;
3410 if (! current_function_sp_is_unchanging)
3413 for (insn = f; insn; insn = NEXT_INSN (insn))
3417 /* Check if insn modifies the stack pointer. */
3418 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
3420 if (! current_function_sp_is_unchanging)
3426 /* Mark a register in SET. Hard registers in large modes get all
3427 of their component registers set as well. */
3430 mark_reg (reg, xset)
3434 regset set = (regset) xset;
3435 int regno = REGNO (reg);
3437 if (GET_MODE (reg) == BLKmode)
3440 SET_REGNO_REG_SET (set, regno);
3441 if (regno < FIRST_PSEUDO_REGISTER)
3443 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
3445 SET_REGNO_REG_SET (set, regno + n);
3449 /* Mark those regs which are needed at the end of the function as live
3450 at the end of the last basic block. */
3453 mark_regs_live_at_end (set)
3458 /* If exiting needs the right stack value, consider the stack pointer
3459 live at the end of the function. */
3460 if ((HAVE_epilogue && reload_completed)
3461 || ! EXIT_IGNORE_STACK
3462 || (! FRAME_POINTER_REQUIRED
3463 && ! current_function_calls_alloca
3464 && flag_omit_frame_pointer)
3465 || current_function_sp_is_unchanging)
3467 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
3470 /* Mark the frame pointer if needed at the end of the function. If
3471 we end up eliminating it, it will be removed from the live list
3472 of each basic block by reload. */
3474 if (! reload_completed || frame_pointer_needed)
3476 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
3477 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3478 /* If they are different, also mark the hard frame pointer as live. */
3479 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
3480 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
3484 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
3485 /* Many architectures have a GP register even without flag_pic.
3486 Assume the pic register is not in use, or will be handled by
3487 other means, if it is not fixed. */
3488 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
3489 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
3490 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
3493 /* Mark all global registers, and all registers used by the epilogue
3494 as being live at the end of the function since they may be
3495 referenced by our caller. */
3496 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3497 if (global_regs[i] || EPILOGUE_USES (i))
3498 SET_REGNO_REG_SET (set, i);
3500 /* Mark all call-saved registers that we actaully used. */
3501 if (HAVE_epilogue && reload_completed)
3503 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3504 if (regs_ever_live[i] && ! call_used_regs[i] && ! LOCAL_REGNO (i))
3505 SET_REGNO_REG_SET (set, i);
3508 /* Mark function return value. */
3509 diddle_return_value (mark_reg, set);
3512 /* Callback function for for_each_successor_phi. DATA is a regset.
3513 Sets the SRC_REGNO, the regno of the phi alternative for phi node
3514 INSN, in the regset. */
3517 set_phi_alternative_reg (insn, dest_regno, src_regno, data)
3518 rtx insn ATTRIBUTE_UNUSED;
3519 int dest_regno ATTRIBUTE_UNUSED;
3523 regset live = (regset) data;
3524 SET_REGNO_REG_SET (live, src_regno);
3528 /* Propagate global life info around the graph of basic blocks. Begin
3529 considering blocks with their corresponding bit set in BLOCKS_IN.
3530 If BLOCKS_IN is null, consider it the universal set.
3532 BLOCKS_OUT is set for every block that was changed. */
3535 calculate_global_regs_live (blocks_in, blocks_out, flags)
3536 sbitmap blocks_in, blocks_out;
3539 basic_block *queue, *qhead, *qtail, *qend;
3540 regset tmp, new_live_at_end;
3541 regset_head tmp_head;
3542 regset_head new_live_at_end_head;
3545 tmp = INITIALIZE_REG_SET (tmp_head);
3546 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
3548 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
3549 because the `head == tail' style test for an empty queue doesn't
3550 work with a full queue. */
3551 queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
3553 qhead = qend = queue + n_basic_blocks + 2;
3555 /* Queue the blocks set in the initial mask. Do this in reverse block
3556 number order so that we are more likely for the first round to do
3557 useful work. We use AUX non-null to flag that the block is queued. */
3560 /* Clear out the garbage that might be hanging out in bb->aux. */
3561 for (i = n_basic_blocks - 1; i >= 0; --i)
3562 BASIC_BLOCK (i)->aux = NULL;
3564 EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
3566 basic_block bb = BASIC_BLOCK (i);
3573 for (i = 0; i < n_basic_blocks; ++i)
3575 basic_block bb = BASIC_BLOCK (i);
3582 sbitmap_zero (blocks_out);
3584 while (qhead != qtail)
3586 int rescan, changed;
3595 /* Begin by propogating live_at_start from the successor blocks. */
3596 CLEAR_REG_SET (new_live_at_end);
3597 for (e = bb->succ; e; e = e->succ_next)
3599 basic_block sb = e->dest;
3600 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
3603 /* The all-important stack pointer must always be live. */
3604 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
3606 /* Before reload, there are a few registers that must be forced
3607 live everywhere -- which might not already be the case for
3608 blocks within infinite loops. */
3609 if (! reload_completed)
3611 /* Any reference to any pseudo before reload is a potential
3612 reference of the frame pointer. */
3613 SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
3615 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3616 /* Pseudos with argument area equivalences may require
3617 reloading via the argument pointer. */
3618 if (fixed_regs[ARG_POINTER_REGNUM])
3619 SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
3622 /* Any constant, or pseudo with constant equivalences, may
3623 require reloading from memory using the pic register. */
3624 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
3625 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
3626 SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
3629 /* Regs used in phi nodes are not included in
3630 global_live_at_start, since they are live only along a
3631 particular edge. Set those regs that are live because of a
3632 phi node alternative corresponding to this particular block. */
3634 for_each_successor_phi (bb, &set_phi_alternative_reg,
3637 if (bb == ENTRY_BLOCK_PTR)
3639 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3643 /* On our first pass through this block, we'll go ahead and continue.
3644 Recognize first pass by local_set NULL. On subsequent passes, we
3645 get to skip out early if live_at_end wouldn't have changed. */
3647 if (bb->local_set == NULL)
3649 bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3650 bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3655 /* If any bits were removed from live_at_end, we'll have to
3656 rescan the block. This wouldn't be necessary if we had
3657 precalculated local_live, however with PROP_SCAN_DEAD_CODE
3658 local_live is really dependent on live_at_end. */
3659 CLEAR_REG_SET (tmp);
3660 rescan = bitmap_operation (tmp, bb->global_live_at_end,
3661 new_live_at_end, BITMAP_AND_COMPL);
3665 /* If any of the registers in the new live_at_end set are
3666 conditionally set in this basic block, we must rescan.
3667 This is because conditional lifetimes at the end of the
3668 block do not just take the live_at_end set into account,
3669 but also the liveness at the start of each successor
3670 block. We can miss changes in those sets if we only
3671 compare the new live_at_end against the previous one. */
3672 CLEAR_REG_SET (tmp);
3673 rescan = bitmap_operation (tmp, new_live_at_end,
3674 bb->cond_local_set, BITMAP_AND);
3679 /* Find the set of changed bits. Take this opportunity
3680 to notice that this set is empty and early out. */
3681 CLEAR_REG_SET (tmp);
3682 changed = bitmap_operation (tmp, bb->global_live_at_end,
3683 new_live_at_end, BITMAP_XOR);
3687 /* If any of the changed bits overlap with local_set,
3688 we'll have to rescan the block. Detect overlap by
3689 the AND with ~local_set turning off bits. */
3690 rescan = bitmap_operation (tmp, tmp, bb->local_set,
3695 /* Let our caller know that BB changed enough to require its
3696 death notes updated. */
3698 SET_BIT (blocks_out, bb->index);
3702 /* Add to live_at_start the set of all registers in
3703 new_live_at_end that aren't in the old live_at_end. */
3705 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
3707 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3709 changed = bitmap_operation (bb->global_live_at_start,
3710 bb->global_live_at_start,
3717 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3719 /* Rescan the block insn by insn to turn (a copy of) live_at_end
3720 into live_at_start. */
3721 propagate_block (bb, new_live_at_end, bb->local_set,
3722 bb->cond_local_set, flags);
3724 /* If live_at start didn't change, no need to go farther. */
3725 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
3728 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
3731 /* Queue all predecessors of BB so that we may re-examine
3732 their live_at_end. */
3733 for (e = bb->pred; e; e = e->pred_next)
3735 basic_block pb = e->src;
3736 if (pb->aux == NULL)
3747 FREE_REG_SET (new_live_at_end);
3751 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
3753 basic_block bb = BASIC_BLOCK (i);
3754 FREE_REG_SET (bb->local_set);
3755 FREE_REG_SET (bb->cond_local_set);
3760 for (i = n_basic_blocks - 1; i >= 0; --i)
3762 basic_block bb = BASIC_BLOCK (i);
3763 FREE_REG_SET (bb->local_set);
3764 FREE_REG_SET (bb->cond_local_set);
3771 /* Subroutines of life analysis. */
3773 /* Allocate the permanent data structures that represent the results
3774 of life analysis. Not static since used also for stupid life analysis. */
3777 allocate_bb_life_data ()
3781 for (i = 0; i < n_basic_blocks; i++)
3783 basic_block bb = BASIC_BLOCK (i);
3785 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3786 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3789 ENTRY_BLOCK_PTR->global_live_at_end
3790 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3791 EXIT_BLOCK_PTR->global_live_at_start
3792 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3794 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
3798 allocate_reg_life_data ()
3802 max_regno = max_reg_num ();
3804 /* Recalculate the register space, in case it has grown. Old style
3805 vector oriented regsets would set regset_{size,bytes} here also. */
3806 allocate_reg_info (max_regno, FALSE, FALSE);
3808 /* Reset all the data we'll collect in propagate_block and its
3810 for (i = 0; i < max_regno; i++)
3814 REG_N_DEATHS (i) = 0;
3815 REG_N_CALLS_CROSSED (i) = 0;
3816 REG_LIVE_LENGTH (i) = 0;
3817 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
3821 /* Delete dead instructions for propagate_block. */
3824 propagate_block_delete_insn (bb, insn)
3828 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
3830 /* If the insn referred to a label, and that label was attached to
3831 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
3832 pretty much mandatory to delete it, because the ADDR_VEC may be
3833 referencing labels that no longer exist. */
3837 rtx label = XEXP (inote, 0);
3840 if (LABEL_NUSES (label) == 1
3841 && (next = next_nonnote_insn (label)) != NULL
3842 && GET_CODE (next) == JUMP_INSN
3843 && (GET_CODE (PATTERN (next)) == ADDR_VEC
3844 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
3846 rtx pat = PATTERN (next);
3847 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
3848 int len = XVECLEN (pat, diff_vec_p);
3851 for (i = 0; i < len; i++)
3852 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
3854 flow_delete_insn (next);
3858 if (bb->end == insn)
3859 bb->end = PREV_INSN (insn);
3860 flow_delete_insn (insn);
3863 /* Delete dead libcalls for propagate_block. Return the insn
3864 before the libcall. */
3867 propagate_block_delete_libcall (bb, insn, note)
3871 rtx first = XEXP (note, 0);
3872 rtx before = PREV_INSN (first);
3874 if (insn == bb->end)
3877 flow_delete_insn_chain (first, insn);
3881 /* Update the life-status of regs for one insn. Return the previous insn. */
3884 propagate_one_insn (pbi, insn)
3885 struct propagate_block_info *pbi;
3888 rtx prev = PREV_INSN (insn);
3889 int flags = pbi->flags;
3890 int insn_is_dead = 0;
3891 int libcall_is_dead = 0;
3895 if (! INSN_P (insn))
3898 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
3899 if (flags & PROP_SCAN_DEAD_CODE)
3901 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
3902 libcall_is_dead = (insn_is_dead && note != 0
3903 && libcall_dead_p (pbi, note, insn));
3906 /* If an instruction consists of just dead store(s) on final pass,
3908 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
3910 /* If we're trying to delete a prologue or epilogue instruction
3911 that isn't flagged as possibly being dead, something is wrong.
3912 But if we are keeping the stack pointer depressed, we might well
3913 be deleting insns that are used to compute the amount to update
3914 it by, so they are fine. */
3915 if (reload_completed
3916 && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
3917 && (TYPE_RETURNS_STACK_DEPRESSED
3918 (TREE_TYPE (current_function_decl))))
3919 && (((HAVE_epilogue || HAVE_prologue)
3920 && prologue_epilogue_contains (insn))
3921 || (HAVE_sibcall_epilogue
3922 && sibcall_epilogue_contains (insn)))
3923 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
3926 /* Record sets. Do this even for dead instructions, since they
3927 would have killed the values if they hadn't been deleted. */
3928 mark_set_regs (pbi, PATTERN (insn), insn);
3930 /* CC0 is now known to be dead. Either this insn used it,
3931 in which case it doesn't anymore, or clobbered it,
3932 so the next insn can't use it. */
3935 if (libcall_is_dead)
3937 prev = propagate_block_delete_libcall (pbi->bb, insn, note);
3938 insn = NEXT_INSN (prev);
3941 propagate_block_delete_insn (pbi->bb, insn);
3946 /* See if this is an increment or decrement that can be merged into
3947 a following memory address. */
3950 register rtx x = single_set (insn);
3952 /* Does this instruction increment or decrement a register? */
3953 if ((flags & PROP_AUTOINC)
3955 && GET_CODE (SET_DEST (x)) == REG
3956 && (GET_CODE (SET_SRC (x)) == PLUS
3957 || GET_CODE (SET_SRC (x)) == MINUS)
3958 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
3959 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
3960 /* Ok, look for a following memory ref we can combine with.
3961 If one is found, change the memory ref to a PRE_INC
3962 or PRE_DEC, cancel this insn, and return 1.
3963 Return 0 if nothing has been done. */
3964 && try_pre_increment_1 (pbi, insn))
3967 #endif /* AUTO_INC_DEC */
3969 CLEAR_REG_SET (pbi->new_set);
3971 /* If this is not the final pass, and this insn is copying the value of
3972 a library call and it's dead, don't scan the insns that perform the
3973 library call, so that the call's arguments are not marked live. */
3974 if (libcall_is_dead)
3976 /* Record the death of the dest reg. */
3977 mark_set_regs (pbi, PATTERN (insn), insn);
3979 insn = XEXP (note, 0);
3980 return PREV_INSN (insn);
3982 else if (GET_CODE (PATTERN (insn)) == SET
3983 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
3984 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
3985 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
3986 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
3987 /* We have an insn to pop a constant amount off the stack.
3988 (Such insns use PLUS regardless of the direction of the stack,
3989 and any insn to adjust the stack by a constant is always a pop.)
3990 These insns, if not dead stores, have no effect on life. */
3994 /* Any regs live at the time of a call instruction must not go
3995 in a register clobbered by calls. Find all regs now live and
3996 record this for them. */
3998 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
3999 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
4000 { REG_N_CALLS_CROSSED (i)++; });
4002 /* Record sets. Do this even for dead instructions, since they
4003 would have killed the values if they hadn't been deleted. */
4004 mark_set_regs (pbi, PATTERN (insn), insn);
4006 if (GET_CODE (insn) == CALL_INSN)
4012 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
4013 cond = COND_EXEC_TEST (PATTERN (insn));
4015 /* Non-constant calls clobber memory. */
4016 if (! CONST_CALL_P (insn))
4018 free_EXPR_LIST_list (&pbi->mem_set_list);
4019 pbi->mem_set_list_len = 0;
4022 /* There may be extra registers to be clobbered. */
4023 for (note = CALL_INSN_FUNCTION_USAGE (insn);
4025 note = XEXP (note, 1))
4026 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
4027 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
4028 cond, insn, pbi->flags);
4030 /* Calls change all call-used and global registers. */
4031 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
4032 if (call_used_regs[i] && ! global_regs[i]
4035 /* We do not want REG_UNUSED notes for these registers. */
4036 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
4038 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
4042 /* If an insn doesn't use CC0, it becomes dead since we assume
4043 that every insn clobbers it. So show it dead here;
4044 mark_used_regs will set it live if it is referenced. */
4049 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
4051 /* Sometimes we may have inserted something before INSN (such as a move)
4052 when we make an auto-inc. So ensure we will scan those insns. */
4054 prev = PREV_INSN (insn);
4057 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
4063 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
4064 cond = COND_EXEC_TEST (PATTERN (insn));
4066 /* Calls use their arguments. */
4067 for (note = CALL_INSN_FUNCTION_USAGE (insn);
4069 note = XEXP (note, 1))
4070 if (GET_CODE (XEXP (note, 0)) == USE)
4071 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
4074 /* The stack ptr is used (honorarily) by a CALL insn. */
4075 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
4077 /* Calls may also reference any of the global registers,
4078 so they are made live. */
4079 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
4081 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
4086 /* On final pass, update counts of how many insns in which each reg
4088 if (flags & PROP_REG_INFO)
4089 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
4090 { REG_LIVE_LENGTH (i)++; });
4095 /* Initialize a propagate_block_info struct for public consumption.
4096 Note that the structure itself is opaque to this file, but that
4097 the user can use the regsets provided here. */
4099 struct propagate_block_info *
4100 init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
4102 regset live, local_set, cond_local_set;
4105 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
4108 pbi->reg_live = live;
4109 pbi->mem_set_list = NULL_RTX;
4110 pbi->mem_set_list_len = 0;
4111 pbi->local_set = local_set;
4112 pbi->cond_local_set = cond_local_set;
4116 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4117 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
4119 pbi->reg_next_use = NULL;
4121 pbi->new_set = BITMAP_XMALLOC ();
4123 #ifdef HAVE_conditional_execution
4124 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
4125 free_reg_cond_life_info);
4126 pbi->reg_cond_reg = BITMAP_XMALLOC ();
4128 /* If this block ends in a conditional branch, for each register live
4129 from one side of the branch and not the other, record the register
4130 as conditionally dead. */
4131 if (GET_CODE (bb->end) == JUMP_INSN
4132 && any_condjump_p (bb->end))
4134 regset_head diff_head;
4135 regset diff = INITIALIZE_REG_SET (diff_head);
4136 basic_block bb_true, bb_false;
4137 rtx cond_true, cond_false, set_src;
4140 /* Identify the successor blocks. */
4141 bb_true = bb->succ->dest;
4142 if (bb->succ->succ_next != NULL)
4144 bb_false = bb->succ->succ_next->dest;
4146 if (bb->succ->flags & EDGE_FALLTHRU)
4148 basic_block t = bb_false;
4152 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
4157 /* This can happen with a conditional jump to the next insn. */
4158 if (JUMP_LABEL (bb->end) != bb_true->head)
4161 /* Simplest way to do nothing. */
4165 /* Extract the condition from the branch. */
4166 set_src = SET_SRC (pc_set (bb->end));
4167 cond_true = XEXP (set_src, 0);
4168 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
4169 GET_MODE (cond_true), XEXP (cond_true, 0),
4170 XEXP (cond_true, 1));
4171 if (GET_CODE (XEXP (set_src, 1)) == PC)
4174 cond_false = cond_true;
4178 /* Compute which register lead different lives in the successors. */
4179 if (bitmap_operation (diff, bb_true->global_live_at_start,
4180 bb_false->global_live_at_start, BITMAP_XOR))
4182 rtx reg = XEXP (cond_true, 0);
4184 if (GET_CODE (reg) == SUBREG)
4185 reg = SUBREG_REG (reg);
4187 if (GET_CODE (reg) != REG)
4190 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
4192 /* For each such register, mark it conditionally dead. */
4193 EXECUTE_IF_SET_IN_REG_SET
4196 struct reg_cond_life_info *rcli;
4199 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
4201 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
4205 rcli->condition = cond;
4207 splay_tree_insert (pbi->reg_cond_dead, i,
4208 (splay_tree_value) rcli);
4212 FREE_REG_SET (diff);
4216 /* If this block has no successors, any stores to the frame that aren't
4217 used later in the block are dead. So make a pass over the block
4218 recording any such that are made and show them dead at the end. We do
4219 a very conservative and simple job here. */
4221 && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
4222 && (TYPE_RETURNS_STACK_DEPRESSED
4223 (TREE_TYPE (current_function_decl))))
4224 && (flags & PROP_SCAN_DEAD_CODE)
4225 && (bb->succ == NULL
4226 || (bb->succ->succ_next == NULL
4227 && bb->succ->dest == EXIT_BLOCK_PTR)))
4230 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
4231 if (GET_CODE (insn) == INSN
4232 && (set = single_set (insn))
4233 && GET_CODE (SET_DEST (set)) == MEM)
4235 rtx mem = SET_DEST (set);
4236 rtx canon_mem = canon_rtx (mem);
4238 /* This optimization is performed by faking a store to the
4239 memory at the end of the block. This doesn't work for
4240 unchanging memories because multiple stores to unchanging
4241 memory is illegal and alias analysis doesn't consider it. */
4242 if (RTX_UNCHANGING_P (canon_mem))
4245 if (XEXP (canon_mem, 0) == frame_pointer_rtx
4246 || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
4247 && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
4248 && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
4251 /* Store a copy of mem, otherwise the address may be scrogged
4252 by find_auto_inc. This matters because insn_dead_p uses
4253 an rtx_equal_p check to determine if two addresses are
4254 the same. This works before find_auto_inc, but fails
4255 after find_auto_inc, causing discrepencies between the
4256 set of live registers calculated during the
4257 calculate_global_regs_live phase and what actually exists
4258 after flow completes, leading to aborts. */
4259 if (flags & PROP_AUTOINC)
4260 mem = shallow_copy_rtx (mem);
4262 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
4263 if (++pbi->mem_set_list_len >= MAX_MEM_SET_LIST_LEN)
4272 /* Release a propagate_block_info struct. */
4275 free_propagate_block_info (pbi)
4276 struct propagate_block_info *pbi;
4278 free_EXPR_LIST_list (&pbi->mem_set_list);
4280 BITMAP_XFREE (pbi->new_set);
4282 #ifdef HAVE_conditional_execution
4283 splay_tree_delete (pbi->reg_cond_dead);
4284 BITMAP_XFREE (pbi->reg_cond_reg);
4287 if (pbi->reg_next_use)
4288 free (pbi->reg_next_use);
4293 /* Compute the registers live at the beginning of a basic block BB from
4294 those live at the end.
4296 When called, REG_LIVE contains those live at the end. On return, it
4297 contains those live at the beginning.
4299 LOCAL_SET, if non-null, will be set with all registers killed
4300 unconditionally by this basic block.
4301 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
4302 killed conditionally by this basic block. If there is any unconditional
4303 set of a register, then the corresponding bit will be set in LOCAL_SET
4304 and cleared in COND_LOCAL_SET.
4305 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
4306 case, the resulting set will be equal to the union of the two sets that
4307 would otherwise be computed. */
4310 propagate_block (bb, live, local_set, cond_local_set, flags)
4314 regset cond_local_set;
4317 struct propagate_block_info *pbi;
4320 pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
4322 if (flags & PROP_REG_INFO)
4326 /* Process the regs live at the end of the block.
4327 Mark them as not local to any one basic block. */
4328 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
4329 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
4332 /* Scan the block an insn at a time from end to beginning. */
4334 for (insn = bb->end;; insn = prev)
4336 /* If this is a call to `setjmp' et al, warn if any
4337 non-volatile datum is live. */
4338 if ((flags & PROP_REG_INFO)
4339 && GET_CODE (insn) == NOTE
4340 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
4341 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
4343 prev = propagate_one_insn (pbi, insn);
4345 if (insn == bb->head)
4349 free_propagate_block_info (pbi);
4352 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
4353 (SET expressions whose destinations are registers dead after the insn).
4354 NEEDED is the regset that says which regs are alive after the insn.
4356 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
4358 If X is the entire body of an insn, NOTES contains the reg notes
4359 pertaining to the insn. */
4362 insn_dead_p (pbi, x, call_ok, notes)
4363 struct propagate_block_info *pbi;
4366 rtx notes ATTRIBUTE_UNUSED;
4368 enum rtx_code code = GET_CODE (x);
4371 /* If flow is invoked after reload, we must take existing AUTO_INC
4372 expresions into account. */
4373 if (reload_completed)
4375 for (; notes; notes = XEXP (notes, 1))
4377 if (REG_NOTE_KIND (notes) == REG_INC)
4379 int regno = REGNO (XEXP (notes, 0));
4381 /* Don't delete insns to set global regs. */
4382 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
4383 || REGNO_REG_SET_P (pbi->reg_live, regno))
4390 /* If setting something that's a reg or part of one,
4391 see if that register's altered value will be live. */
4395 rtx r = SET_DEST (x);
4398 if (GET_CODE (r) == CC0)
4399 return ! pbi->cc0_live;
4402 /* A SET that is a subroutine call cannot be dead. */
4403 if (GET_CODE (SET_SRC (x)) == CALL)
4409 /* Don't eliminate loads from volatile memory or volatile asms. */
4410 else if (volatile_refs_p (SET_SRC (x)))
4413 if (GET_CODE (r) == MEM)
4417 if (MEM_VOLATILE_P (r))
4420 /* Walk the set of memory locations we are currently tracking
4421 and see if one is an identical match to this memory location.
4422 If so, this memory write is dead (remember, we're walking
4423 backwards from the end of the block to the start). */
4424 temp = pbi->mem_set_list;
4427 rtx mem = XEXP (temp, 0);
4429 if (rtx_equal_p (mem, r))
4432 /* Check if memory reference matches an auto increment. Only
4433 post increment/decrement or modify are valid. */
4434 if (GET_MODE (mem) == GET_MODE (r)
4435 && (GET_CODE (XEXP (mem, 0)) == POST_DEC
4436 || GET_CODE (XEXP (mem, 0)) == POST_INC
4437 || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
4438 && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
4439 && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
4442 temp = XEXP (temp, 1);
4447 while (GET_CODE (r) == SUBREG
4448 || GET_CODE (r) == STRICT_LOW_PART
4449 || GET_CODE (r) == ZERO_EXTRACT)
4452 if (GET_CODE (r) == REG)
4454 int regno = REGNO (r);
4457 if (REGNO_REG_SET_P (pbi->reg_live, regno))
4460 /* If this is a hard register, verify that subsequent
4461 words are not needed. */
4462 if (regno < FIRST_PSEUDO_REGISTER)
4464 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
4467 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
4471 /* Don't delete insns to set global regs. */
4472 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
4475 /* Make sure insns to set the stack pointer aren't deleted. */
4476 if (regno == STACK_POINTER_REGNUM)
4479 /* ??? These bits might be redundant with the force live bits
4480 in calculate_global_regs_live. We would delete from
4481 sequential sets; whether this actually affects real code
4482 for anything but the stack pointer I don't know. */
4483 /* Make sure insns to set the frame pointer aren't deleted. */
4484 if (regno == FRAME_POINTER_REGNUM
4485 && (! reload_completed || frame_pointer_needed))
4487 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4488 if (regno == HARD_FRAME_POINTER_REGNUM
4489 && (! reload_completed || frame_pointer_needed))
4493 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4494 /* Make sure insns to set arg pointer are never deleted
4495 (if the arg pointer isn't fixed, there will be a USE
4496 for it, so we can treat it normally). */
4497 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
4501 /* Otherwise, the set is dead. */
4507 /* If performing several activities, insn is dead if each activity
4508 is individually dead. Also, CLOBBERs and USEs can be ignored; a
4509 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
4511 else if (code == PARALLEL)
4513 int i = XVECLEN (x, 0);
4515 for (i--; i >= 0; i--)
4516 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
4517 && GET_CODE (XVECEXP (x, 0, i)) != USE
4518 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
4524 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
4525 is not necessarily true for hard registers. */
4526 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
4527 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
4528 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
4531 /* We do not check other CLOBBER or USE here. An insn consisting of just
4532 a CLOBBER or just a USE should not be deleted. */
4536 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
4537 return 1 if the entire library call is dead.
4538 This is true if INSN copies a register (hard or pseudo)
4539 and if the hard return reg of the call insn is dead.
4540 (The caller should have tested the destination of the SET inside
4541 INSN already for death.)
4543 If this insn doesn't just copy a register, then we don't
4544 have an ordinary libcall. In that case, cse could not have
4545 managed to substitute the source for the dest later on,
4546 so we can assume the libcall is dead.
4548 PBI is the block info giving pseudoregs live before this insn.
4549 NOTE is the REG_RETVAL note of the insn. */
4552 libcall_dead_p (pbi, note, insn)
4553 struct propagate_block_info *pbi;
4557 rtx x = single_set (insn);
4561 register rtx r = SET_SRC (x);
4562 if (GET_CODE (r) == REG)
4564 rtx call = XEXP (note, 0);
4568 /* Find the call insn. */
4569 while (call != insn && GET_CODE (call) != CALL_INSN)
4570 call = NEXT_INSN (call);
4572 /* If there is none, do nothing special,
4573 since ordinary death handling can understand these insns. */
4577 /* See if the hard reg holding the value is dead.
4578 If this is a PARALLEL, find the call within it. */
4579 call_pat = PATTERN (call);
4580 if (GET_CODE (call_pat) == PARALLEL)
4582 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
4583 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
4584 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
4587 /* This may be a library call that is returning a value
4588 via invisible pointer. Do nothing special, since
4589 ordinary death handling can understand these insns. */
4593 call_pat = XVECEXP (call_pat, 0, i);
4596 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
4602 /* Return 1 if register REGNO was used before it was set, i.e. if it is
4603 live at function entry. Don't count global register variables, variables
4604 in registers that can be used for function arg passing, or variables in
4605 fixed hard registers. */
4608 regno_uninitialized (regno)
4611 if (n_basic_blocks == 0
4612 || (regno < FIRST_PSEUDO_REGISTER
4613 && (global_regs[regno]
4614 || fixed_regs[regno]
4615 || FUNCTION_ARG_REGNO_P (regno))))
4618 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
4621 /* 1 if register REGNO was alive at a place where `setjmp' was called
4622 and was set more than once or is an argument.
4623 Such regs may be clobbered by `longjmp'. */
4626 regno_clobbered_at_setjmp (regno)
4629 if (n_basic_blocks == 0)
4632 return ((REG_N_SETS (regno) > 1
4633 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
4634 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
4637 /* INSN references memory, possibly using autoincrement addressing modes.
4638 Find any entries on the mem_set_list that need to be invalidated due
4639 to an address change. */
4642 invalidate_mems_from_autoinc (pbi, insn)
4643 struct propagate_block_info *pbi;
4646 rtx note = REG_NOTES (insn);
4647 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
4649 if (REG_NOTE_KIND (note) == REG_INC)
4651 rtx temp = pbi->mem_set_list;
4652 rtx prev = NULL_RTX;
4657 next = XEXP (temp, 1);
4658 if (reg_overlap_mentioned_p (XEXP (note, 0), XEXP (temp, 0)))
4660 /* Splice temp out of list. */
4662 XEXP (prev, 1) = next;
4664 pbi->mem_set_list = next;
4665 free_EXPR_LIST_node (temp);
4666 pbi->mem_set_list_len--;
4676 /* EXP is either a MEM or a REG. Remove any dependant entries
4677 from pbi->mem_set_list. */
4680 invalidate_mems_from_set (pbi, exp)
4681 struct propagate_block_info *pbi;
4684 rtx temp = pbi->mem_set_list;
4685 rtx prev = NULL_RTX;
4690 next = XEXP (temp, 1);
4691 if ((GET_CODE (exp) == MEM
4692 && output_dependence (XEXP (temp, 0), exp))
4693 || (GET_CODE (exp) == REG
4694 && reg_overlap_mentioned_p (exp, XEXP (temp, 0))))
4696 /* Splice this entry out of the list. */
4698 XEXP (prev, 1) = next;
4700 pbi->mem_set_list = next;
4701 free_EXPR_LIST_node (temp);
4702 pbi->mem_set_list_len--;
4710 /* Process the registers that are set within X. Their bits are set to
4711 1 in the regset DEAD, because they are dead prior to this insn.
4713 If INSN is nonzero, it is the insn being processed.
4715 FLAGS is the set of operations to perform. */
4718 mark_set_regs (pbi, x, insn)
4719 struct propagate_block_info *pbi;
4722 rtx cond = NULL_RTX;
4727 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
4729 if (REG_NOTE_KIND (link) == REG_INC)
4730 mark_set_1 (pbi, SET, XEXP (link, 0),
4731 (GET_CODE (x) == COND_EXEC
4732 ? COND_EXEC_TEST (x) : NULL_RTX),
4736 switch (code = GET_CODE (x))
4740 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
4744 cond = COND_EXEC_TEST (x);
4745 x = COND_EXEC_CODE (x);
4751 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
4753 rtx sub = XVECEXP (x, 0, i);
4754 switch (code = GET_CODE (sub))
4757 if (cond != NULL_RTX)
4760 cond = COND_EXEC_TEST (sub);
4761 sub = COND_EXEC_CODE (sub);
4762 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
4768 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
4783 /* Process a single SET rtx, X. */
4786 mark_set_1 (pbi, code, reg, cond, insn, flags)
4787 struct propagate_block_info *pbi;
4789 rtx reg, cond, insn;
4792 int regno_first = -1, regno_last = -1;
4793 unsigned long not_dead = 0;
4796 /* Modifying just one hardware register of a multi-reg value or just a
4797 byte field of a register does not mean the value from before this insn
4798 is now dead. Of course, if it was dead after it's unused now. */
4800 switch (GET_CODE (reg))
4803 /* Some targets place small structures in registers for return values of
4804 functions. We have to detect this case specially here to get correct
4805 flow information. */
4806 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
4807 if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
4808 mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
4814 case STRICT_LOW_PART:
4815 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
4817 reg = XEXP (reg, 0);
4818 while (GET_CODE (reg) == SUBREG
4819 || GET_CODE (reg) == ZERO_EXTRACT
4820 || GET_CODE (reg) == SIGN_EXTRACT
4821 || GET_CODE (reg) == STRICT_LOW_PART);
4822 if (GET_CODE (reg) == MEM)
4824 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
4828 regno_last = regno_first = REGNO (reg);
4829 if (regno_first < FIRST_PSEUDO_REGISTER)
4830 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
4834 if (GET_CODE (SUBREG_REG (reg)) == REG)
4836 enum machine_mode outer_mode = GET_MODE (reg);
4837 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
4839 /* Identify the range of registers affected. This is moderately
4840 tricky for hard registers. See alter_subreg. */
4842 regno_last = regno_first = REGNO (SUBREG_REG (reg));
4843 if (regno_first < FIRST_PSEUDO_REGISTER)
4845 #ifdef ALTER_HARD_SUBREG
4846 regno_first = ALTER_HARD_SUBREG (outer_mode, SUBREG_WORD (reg),
4847 inner_mode, regno_first);
4849 regno_first += SUBREG_WORD (reg);
4851 regno_last = (regno_first
4852 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
4854 /* Since we've just adjusted the register number ranges, make
4855 sure REG matches. Otherwise some_was_live will be clear
4856 when it shouldn't have been, and we'll create incorrect
4857 REG_UNUSED notes. */
4858 reg = gen_rtx_REG (outer_mode, regno_first);
4862 /* If the number of words in the subreg is less than the number
4863 of words in the full register, we have a well-defined partial
4864 set. Otherwise the high bits are undefined.
4866 This is only really applicable to pseudos, since we just took
4867 care of multi-word hard registers. */
4868 if (((GET_MODE_SIZE (outer_mode)
4869 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
4870 < ((GET_MODE_SIZE (inner_mode)
4871 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
4872 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
4875 reg = SUBREG_REG (reg);
4879 reg = SUBREG_REG (reg);
4886 /* If this set is a MEM, then it kills any aliased writes.
4887 If this set is a REG, then it kills any MEMs which use the reg. */
4888 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
4890 if (GET_CODE (reg) == MEM || GET_CODE (reg) == REG)
4891 invalidate_mems_from_set (pbi, reg);
4893 /* If the memory reference had embedded side effects (autoincrement
4894 address modes. Then we may need to kill some entries on the
4896 if (insn && GET_CODE (reg) == MEM)
4897 invalidate_mems_from_autoinc (pbi, insn);
4899 if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN
4900 && GET_CODE (reg) == MEM && ! side_effects_p (reg)
4901 /* ??? With more effort we could track conditional memory life. */
4903 /* We do not know the size of a BLKmode store, so we do not track
4904 them for redundant store elimination. */
4905 && GET_MODE (reg) != BLKmode
4906 /* There are no REG_INC notes for SP, so we can't assume we'll see
4907 everything that invalidates it. To be safe, don't eliminate any
4908 stores though SP; none of them should be redundant anyway. */
4909 && ! reg_mentioned_p (stack_pointer_rtx, reg))
4912 /* Store a copy of mem, otherwise the address may be
4913 scrogged by find_auto_inc. */
4914 if (flags & PROP_AUTOINC)
4915 reg = shallow_copy_rtx (reg);
4917 pbi->mem_set_list = alloc_EXPR_LIST (0, reg, pbi->mem_set_list);
4918 pbi->mem_set_list_len++;
4922 if (GET_CODE (reg) == REG
4923 && ! (regno_first == FRAME_POINTER_REGNUM
4924 && (! reload_completed || frame_pointer_needed))
4925 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4926 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
4927 && (! reload_completed || frame_pointer_needed))
4929 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4930 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
4934 int some_was_live = 0, some_was_dead = 0;
4936 for (i = regno_first; i <= regno_last; ++i)
4938 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
4941 /* Order of the set operation matters here since both
4942 sets may be the same. */
4943 CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
4944 if (cond != NULL_RTX
4945 && ! REGNO_REG_SET_P (pbi->local_set, i))
4946 SET_REGNO_REG_SET (pbi->cond_local_set, i);
4948 SET_REGNO_REG_SET (pbi->local_set, i);
4950 if (code != CLOBBER)
4951 SET_REGNO_REG_SET (pbi->new_set, i);
4953 some_was_live |= needed_regno;
4954 some_was_dead |= ! needed_regno;
4957 #ifdef HAVE_conditional_execution
4958 /* Consider conditional death in deciding that the register needs
4960 if (some_was_live && ! not_dead
4961 /* The stack pointer is never dead. Well, not strictly true,
4962 but it's very difficult to tell from here. Hopefully
4963 combine_stack_adjustments will fix up the most egregious
4965 && regno_first != STACK_POINTER_REGNUM)
4967 for (i = regno_first; i <= regno_last; ++i)
4968 if (! mark_regno_cond_dead (pbi, i, cond))
4969 not_dead |= ((unsigned long) 1) << (i - regno_first);
4973 /* Additional data to record if this is the final pass. */
4974 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
4975 | PROP_DEATH_NOTES | PROP_AUTOINC))
4978 register int blocknum = pbi->bb->index;
4981 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4983 y = pbi->reg_next_use[regno_first];
4985 /* The next use is no longer next, since a store intervenes. */
4986 for (i = regno_first; i <= regno_last; ++i)
4987 pbi->reg_next_use[i] = 0;
4990 if (flags & PROP_REG_INFO)
4992 for (i = regno_first; i <= regno_last; ++i)
4994 /* Count (weighted) references, stores, etc. This counts a
4995 register twice if it is modified, but that is correct. */
4996 REG_N_SETS (i) += 1;
4997 REG_N_REFS (i) += (optimize_size ? 1
4998 : pbi->bb->loop_depth + 1);
5000 /* The insns where a reg is live are normally counted
5001 elsewhere, but we want the count to include the insn
5002 where the reg is set, and the normal counting mechanism
5003 would not count it. */
5004 REG_LIVE_LENGTH (i) += 1;
5007 /* If this is a hard reg, record this function uses the reg. */
5008 if (regno_first < FIRST_PSEUDO_REGISTER)
5010 for (i = regno_first; i <= regno_last; i++)
5011 regs_ever_live[i] = 1;
5015 /* Keep track of which basic blocks each reg appears in. */
5016 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
5017 REG_BASIC_BLOCK (regno_first) = blocknum;
5018 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
5019 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
5023 if (! some_was_dead)
5025 if (flags & PROP_LOG_LINKS)
5027 /* Make a logical link from the next following insn
5028 that uses this register, back to this insn.
5029 The following insns have already been processed.
5031 We don't build a LOG_LINK for hard registers containing
5032 in ASM_OPERANDs. If these registers get replaced,
5033 we might wind up changing the semantics of the insn,
5034 even if reload can make what appear to be valid
5035 assignments later. */
5036 if (y && (BLOCK_NUM (y) == blocknum)
5037 && (regno_first >= FIRST_PSEUDO_REGISTER
5038 || asm_noperands (PATTERN (y)) < 0))
5039 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
5044 else if (! some_was_live)
5046 if (flags & PROP_REG_INFO)
5047 REG_N_DEATHS (regno_first) += 1;
5049 if (flags & PROP_DEATH_NOTES)
5051 /* Note that dead stores have already been deleted
5052 when possible. If we get here, we have found a
5053 dead store that cannot be eliminated (because the
5054 same insn does something useful). Indicate this
5055 by marking the reg being set as dying here. */
5057 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
5062 if (flags & PROP_DEATH_NOTES)
5064 /* This is a case where we have a multi-word hard register
5065 and some, but not all, of the words of the register are
5066 needed in subsequent insns. Write REG_UNUSED notes
5067 for those parts that were not needed. This case should
5070 for (i = regno_first; i <= regno_last; ++i)
5071 if (! REGNO_REG_SET_P (pbi->reg_live, i))
5073 = alloc_EXPR_LIST (REG_UNUSED,
5074 gen_rtx_REG (reg_raw_mode[i], i),
5080 /* Mark the register as being dead. */
5082 /* The stack pointer is never dead. Well, not strictly true,
5083 but it's very difficult to tell from here. Hopefully
5084 combine_stack_adjustments will fix up the most egregious
5086 && regno_first != STACK_POINTER_REGNUM)
5088 for (i = regno_first; i <= regno_last; ++i)
5089 if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
5090 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
5093 else if (GET_CODE (reg) == REG)
5095 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
5096 pbi->reg_next_use[regno_first] = 0;
5099 /* If this is the last pass and this is a SCRATCH, show it will be dying
5100 here and count it. */
5101 else if (GET_CODE (reg) == SCRATCH)
5103 if (flags & PROP_DEATH_NOTES)
5105 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
5109 #ifdef HAVE_conditional_execution
5110 /* Mark REGNO conditionally dead.
5111 Return true if the register is now unconditionally dead. */
5114 mark_regno_cond_dead (pbi, regno, cond)
5115 struct propagate_block_info *pbi;
5119 /* If this is a store to a predicate register, the value of the
5120 predicate is changing, we don't know that the predicate as seen
5121 before is the same as that seen after. Flush all dependent
5122 conditions from reg_cond_dead. This will make all such
5123 conditionally live registers unconditionally live. */
5124 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
5125 flush_reg_cond_reg (pbi, regno);
5127 /* If this is an unconditional store, remove any conditional
5128 life that may have existed. */
5129 if (cond == NULL_RTX)
5130 splay_tree_remove (pbi->reg_cond_dead, regno);
5133 splay_tree_node node;
5134 struct reg_cond_life_info *rcli;
5137 /* Otherwise this is a conditional set. Record that fact.
5138 It may have been conditionally used, or there may be a
5139 subsequent set with a complimentary condition. */
5141 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
5144 /* The register was unconditionally live previously.
5145 Record the current condition as the condition under
5146 which it is dead. */
5147 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
5148 rcli->condition = cond;
5149 splay_tree_insert (pbi->reg_cond_dead, regno,
5150 (splay_tree_value) rcli);
5152 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5154 /* Not unconditionaly dead. */
5159 /* The register was conditionally live previously.
5160 Add the new condition to the old. */
5161 rcli = (struct reg_cond_life_info *) node->value;
5162 ncond = rcli->condition;
5163 ncond = ior_reg_cond (ncond, cond, 1);
5165 /* If the register is now unconditionally dead,
5166 remove the entry in the splay_tree. */
5167 if (ncond == const1_rtx)
5168 splay_tree_remove (pbi->reg_cond_dead, regno);
5171 rcli->condition = ncond;
5173 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5175 /* Not unconditionaly dead. */
5184 /* Called from splay_tree_delete for pbi->reg_cond_life. */
5187 free_reg_cond_life_info (value)
5188 splay_tree_value value;
5190 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
5194 /* Helper function for flush_reg_cond_reg. */
5197 flush_reg_cond_reg_1 (node, data)
5198 splay_tree_node node;
5201 struct reg_cond_life_info *rcli;
5202 int *xdata = (int *) data;
5203 unsigned int regno = xdata[0];
5205 /* Don't need to search if last flushed value was farther on in
5206 the in-order traversal. */
5207 if (xdata[1] >= (int) node->key)
5210 /* Splice out portions of the expression that refer to regno. */
5211 rcli = (struct reg_cond_life_info *) node->value;
5212 rcli->condition = elim_reg_cond (rcli->condition, regno);
5214 /* If the entire condition is now false, signal the node to be removed. */
5215 if (rcli->condition == const0_rtx)
5217 xdata[1] = node->key;
5220 else if (rcli->condition == const1_rtx)
5226 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
5229 flush_reg_cond_reg (pbi, regno)
5230 struct propagate_block_info *pbi;
5237 while (splay_tree_foreach (pbi->reg_cond_dead,
5238 flush_reg_cond_reg_1, pair) == -1)
5239 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
5241 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
5244 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
5245 For ior/and, the ADD flag determines whether we want to add the new
5246 condition X to the old one unconditionally. If it is zero, we will
5247 only return a new expression if X allows us to simplify part of
5248 OLD, otherwise we return OLD unchanged to the caller.
5249 If ADD is nonzero, we will return a new condition in all cases. The
5250 toplevel caller of one of these functions should always pass 1 for
5254 ior_reg_cond (old, x, add)
5260 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
5262 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
5263 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
5264 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5266 if (GET_CODE (x) == GET_CODE (old)
5267 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5271 return gen_rtx_IOR (0, old, x);
5274 switch (GET_CODE (old))
5277 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
5278 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
5279 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5281 if (op0 == const0_rtx)
5283 if (op1 == const0_rtx)
5285 if (op0 == const1_rtx || op1 == const1_rtx)
5287 if (op0 == XEXP (old, 0))
5288 op0 = gen_rtx_IOR (0, op0, x);
5290 op1 = gen_rtx_IOR (0, op1, x);
5291 return gen_rtx_IOR (0, op0, op1);
5295 return gen_rtx_IOR (0, old, x);
5298 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
5299 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
5300 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5302 if (op0 == const1_rtx)
5304 if (op1 == const1_rtx)
5306 if (op0 == const0_rtx || op1 == const0_rtx)
5308 if (op0 == XEXP (old, 0))
5309 op0 = gen_rtx_IOR (0, op0, x);
5311 op1 = gen_rtx_IOR (0, op1, x);
5312 return gen_rtx_AND (0, op0, op1);
5316 return gen_rtx_IOR (0, old, x);
5319 op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
5320 if (op0 != XEXP (old, 0))
5321 return not_reg_cond (op0);
5324 return gen_rtx_IOR (0, old, x);
5335 enum rtx_code x_code;
5337 if (x == const0_rtx)
5339 else if (x == const1_rtx)
5341 x_code = GET_CODE (x);
5344 if (GET_RTX_CLASS (x_code) == '<'
5345 && GET_CODE (XEXP (x, 0)) == REG)
5347 if (XEXP (x, 1) != const0_rtx)
5350 return gen_rtx_fmt_ee (reverse_condition (x_code),
5351 VOIDmode, XEXP (x, 0), const0_rtx);
5353 return gen_rtx_NOT (0, x);
5357 and_reg_cond (old, x, add)
5363 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
5365 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
5366 && GET_CODE (x) == reverse_condition (GET_CODE (old))
5367 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5369 if (GET_CODE (x) == GET_CODE (old)
5370 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
5374 return gen_rtx_AND (0, old, x);
5377 switch (GET_CODE (old))
5380 op0 = and_reg_cond (XEXP (old, 0), x, 0);
5381 op1 = and_reg_cond (XEXP (old, 1), x, 0);
5382 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5384 if (op0 == const0_rtx)
5386 if (op1 == const0_rtx)
5388 if (op0 == const1_rtx || op1 == const1_rtx)
5390 if (op0 == XEXP (old, 0))
5391 op0 = gen_rtx_AND (0, op0, x);
5393 op1 = gen_rtx_AND (0, op1, x);
5394 return gen_rtx_IOR (0, op0, op1);
5398 return gen_rtx_AND (0, old, x);
5401 op0 = and_reg_cond (XEXP (old, 0), x, 0);
5402 op1 = and_reg_cond (XEXP (old, 1), x, 0);
5403 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
5405 if (op0 == const1_rtx)
5407 if (op1 == const1_rtx)
5409 if (op0 == const0_rtx || op1 == const0_rtx)
5411 if (op0 == XEXP (old, 0))
5412 op0 = gen_rtx_AND (0, op0, x);
5414 op1 = gen_rtx_AND (0, op1, x);
5415 return gen_rtx_AND (0, op0, op1);
5419 return gen_rtx_AND (0, old, x);
5422 op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
5423 if (op0 != XEXP (old, 0))
5424 return not_reg_cond (op0);
5427 return gen_rtx_AND (0, old, x);
5434 /* Given a condition X, remove references to reg REGNO and return the
5435 new condition. The removal will be done so that all conditions
5436 involving REGNO are considered to evaluate to false. This function
5437 is used when the value of REGNO changes. */
5440 elim_reg_cond (x, regno)
5446 if (GET_RTX_CLASS (GET_CODE (x)) == '<')
5448 if (REGNO (XEXP (x, 0)) == regno)
5453 switch (GET_CODE (x))
5456 op0 = elim_reg_cond (XEXP (x, 0), regno);
5457 op1 = elim_reg_cond (XEXP (x, 1), regno);
5458 if (op0 == const0_rtx || op1 == const0_rtx)
5460 if (op0 == const1_rtx)
5462 if (op1 == const1_rtx)
5464 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
5466 return gen_rtx_AND (0, op0, op1);
5469 op0 = elim_reg_cond (XEXP (x, 0), regno);
5470 op1 = elim_reg_cond (XEXP (x, 1), regno);
5471 if (op0 == const1_rtx || op1 == const1_rtx)
5473 if (op0 == const0_rtx)
5475 if (op1 == const0_rtx)
5477 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
5479 return gen_rtx_IOR (0, op0, op1);
5482 op0 = elim_reg_cond (XEXP (x, 0), regno);
5483 if (op0 == const0_rtx)
5485 if (op0 == const1_rtx)
5487 if (op0 != XEXP (x, 0))
5488 return not_reg_cond (op0);
5495 #endif /* HAVE_conditional_execution */
5499 /* Try to substitute the auto-inc expression INC as the address inside
5500 MEM which occurs in INSN. Currently, the address of MEM is an expression
5501 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
5502 that has a single set whose source is a PLUS of INCR_REG and something
5506 attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
5507 struct propagate_block_info *pbi;
5508 rtx inc, insn, mem, incr, incr_reg;
5510 int regno = REGNO (incr_reg);
5511 rtx set = single_set (incr);
5512 rtx q = SET_DEST (set);
5513 rtx y = SET_SRC (set);
5514 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
5516 /* Make sure this reg appears only once in this insn. */
5517 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
5520 if (dead_or_set_p (incr, incr_reg)
5521 /* Mustn't autoinc an eliminable register. */
5522 && (regno >= FIRST_PSEUDO_REGISTER
5523 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
5525 /* This is the simple case. Try to make the auto-inc. If
5526 we can't, we are done. Otherwise, we will do any
5527 needed updates below. */
5528 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
5531 else if (GET_CODE (q) == REG
5532 /* PREV_INSN used here to check the semi-open interval
5534 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
5535 /* We must also check for sets of q as q may be
5536 a call clobbered hard register and there may
5537 be a call between PREV_INSN (insn) and incr. */
5538 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
5540 /* We have *p followed sometime later by q = p+size.
5541 Both p and q must be live afterward,
5542 and q is not used between INSN and its assignment.
5543 Change it to q = p, ...*q..., q = q+size.
5544 Then fall into the usual case. */
5548 emit_move_insn (q, incr_reg);
5549 insns = get_insns ();
5552 if (basic_block_for_insn)
5553 for (temp = insns; temp; temp = NEXT_INSN (temp))
5554 set_block_for_insn (temp, pbi->bb);
5556 /* If we can't make the auto-inc, or can't make the
5557 replacement into Y, exit. There's no point in making
5558 the change below if we can't do the auto-inc and doing
5559 so is not correct in the pre-inc case. */
5562 validate_change (insn, &XEXP (mem, 0), inc, 1);
5563 validate_change (incr, &XEXP (y, opnum), q, 1);
5564 if (! apply_change_group ())
5567 /* We now know we'll be doing this change, so emit the
5568 new insn(s) and do the updates. */
5569 emit_insns_before (insns, insn);
5571 if (pbi->bb->head == insn)
5572 pbi->bb->head = insns;
5574 /* INCR will become a NOTE and INSN won't contain a
5575 use of INCR_REG. If a use of INCR_REG was just placed in
5576 the insn before INSN, make that the next use.
5577 Otherwise, invalidate it. */
5578 if (GET_CODE (PREV_INSN (insn)) == INSN
5579 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
5580 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
5581 pbi->reg_next_use[regno] = PREV_INSN (insn);
5583 pbi->reg_next_use[regno] = 0;
5588 /* REGNO is now used in INCR which is below INSN, but
5589 it previously wasn't live here. If we don't mark
5590 it as live, we'll put a REG_DEAD note for it
5591 on this insn, which is incorrect. */
5592 SET_REGNO_REG_SET (pbi->reg_live, regno);
5594 /* If there are any calls between INSN and INCR, show
5595 that REGNO now crosses them. */
5596 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
5597 if (GET_CODE (temp) == CALL_INSN)
5598 REG_N_CALLS_CROSSED (regno)++;
5603 /* If we haven't returned, it means we were able to make the
5604 auto-inc, so update the status. First, record that this insn
5605 has an implicit side effect. */
5607 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
5609 /* Modify the old increment-insn to simply copy
5610 the already-incremented value of our register. */
5611 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
5614 /* If that makes it a no-op (copying the register into itself) delete
5615 it so it won't appear to be a "use" and a "set" of this
5617 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
5619 /* If the original source was dead, it's dead now. */
5622 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
5624 remove_note (incr, note);
5625 if (XEXP (note, 0) != incr_reg)
5626 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
5629 PUT_CODE (incr, NOTE);
5630 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
5631 NOTE_SOURCE_FILE (incr) = 0;
5634 if (regno >= FIRST_PSEUDO_REGISTER)
5636 /* Count an extra reference to the reg. When a reg is
5637 incremented, spilling it is worse, so we want to make
5638 that less likely. */
5639 REG_N_REFS (regno) += (optimize_size ? 1 : pbi->bb->loop_depth + 1);
5641 /* Count the increment as a setting of the register,
5642 even though it isn't a SET in rtl. */
5643 REG_N_SETS (regno)++;
5647 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
5651 find_auto_inc (pbi, x, insn)
5652 struct propagate_block_info *pbi;
5656 rtx addr = XEXP (x, 0);
5657 HOST_WIDE_INT offset = 0;
5658 rtx set, y, incr, inc_val;
5660 int size = GET_MODE_SIZE (GET_MODE (x));
5662 if (GET_CODE (insn) == JUMP_INSN)
5665 /* Here we detect use of an index register which might be good for
5666 postincrement, postdecrement, preincrement, or predecrement. */
5668 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
5669 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
5671 if (GET_CODE (addr) != REG)
5674 regno = REGNO (addr);
5676 /* Is the next use an increment that might make auto-increment? */
5677 incr = pbi->reg_next_use[regno];
5678 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
5680 set = single_set (incr);
5681 if (set == 0 || GET_CODE (set) != SET)
5685 if (GET_CODE (y) != PLUS)
5688 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
5689 inc_val = XEXP (y, 1);
5690 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
5691 inc_val = XEXP (y, 0);
5695 if (GET_CODE (inc_val) == CONST_INT)
5697 if (HAVE_POST_INCREMENT
5698 && (INTVAL (inc_val) == size && offset == 0))
5699 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
5701 else if (HAVE_POST_DECREMENT
5702 && (INTVAL (inc_val) == -size && offset == 0))
5703 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
5705 else if (HAVE_PRE_INCREMENT
5706 && (INTVAL (inc_val) == size && offset == size))
5707 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
5709 else if (HAVE_PRE_DECREMENT
5710 && (INTVAL (inc_val) == -size && offset == -size))
5711 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
5713 else if (HAVE_POST_MODIFY_DISP && offset == 0)
5714 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
5715 gen_rtx_PLUS (Pmode,
5718 insn, x, incr, addr);
5720 else if (GET_CODE (inc_val) == REG
5721 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
5725 if (HAVE_POST_MODIFY_REG && offset == 0)
5726 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
5727 gen_rtx_PLUS (Pmode,
5730 insn, x, incr, addr);
5734 #endif /* AUTO_INC_DEC */
5737 mark_used_reg (pbi, reg, cond, insn)
5738 struct propagate_block_info *pbi;
5740 rtx cond ATTRIBUTE_UNUSED;
5743 int regno = REGNO (reg);
5744 int some_was_live = REGNO_REG_SET_P (pbi->reg_live, regno);
5745 int some_was_dead = ! some_was_live;
5749 /* A hard reg in a wide mode may really be multiple registers.
5750 If so, mark all of them just like the first. */
5751 if (regno < FIRST_PSEUDO_REGISTER)
5753 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5756 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, regno + n);
5757 some_was_live |= needed_regno;
5758 some_was_dead |= ! needed_regno;
5762 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
5764 /* Record where each reg is used, so when the reg is set we know
5765 the next insn that uses it. */
5766 pbi->reg_next_use[regno] = insn;
5769 if (pbi->flags & PROP_REG_INFO)
5771 if (regno < FIRST_PSEUDO_REGISTER)
5773 /* If this is a register we are going to try to eliminate,
5774 don't mark it live here. If we are successful in
5775 eliminating it, it need not be live unless it is used for
5776 pseudos, in which case it will have been set live when it
5777 was allocated to the pseudos. If the register will not
5778 be eliminated, reload will set it live at that point.
5780 Otherwise, record that this function uses this register. */
5781 /* ??? The PPC backend tries to "eliminate" on the pic
5782 register to itself. This should be fixed. In the mean
5783 time, hack around it. */
5785 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno)
5786 && (regno == FRAME_POINTER_REGNUM
5787 || regno == ARG_POINTER_REGNUM)))
5789 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5791 regs_ever_live[regno + --n] = 1;
5797 /* Keep track of which basic block each reg appears in. */
5799 register int blocknum = pbi->bb->index;
5800 if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN)
5801 REG_BASIC_BLOCK (regno) = blocknum;
5802 else if (REG_BASIC_BLOCK (regno) != blocknum)
5803 REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL;
5805 /* Count (weighted) number of uses of each reg. */
5806 REG_N_REFS (regno) += (optimize_size ? 1
5807 : pbi->bb->loop_depth + 1);
5811 /* Find out if any of the register was set this insn. */
5812 some_not_set = ! REGNO_REG_SET_P (pbi->new_set, regno);
5813 if (regno < FIRST_PSEUDO_REGISTER)
5815 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5817 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, regno + n);
5820 /* Record and count the insns in which a reg dies. If it is used in
5821 this insn and was dead below the insn then it dies in this insn.
5822 If it was set in this insn, we do not make a REG_DEAD note;
5823 likewise if we already made such a note. */
5824 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
5828 /* Check for the case where the register dying partially
5829 overlaps the register set by this insn. */
5830 if (regno < FIRST_PSEUDO_REGISTER
5831 && HARD_REGNO_NREGS (regno, GET_MODE (reg)) > 1)
5833 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5835 some_was_live |= REGNO_REG_SET_P (pbi->new_set, regno + n);
5838 /* If none of the words in X is needed, make a REG_DEAD note.
5839 Otherwise, we must make partial REG_DEAD notes. */
5840 if (! some_was_live)
5842 if ((pbi->flags & PROP_DEATH_NOTES)
5843 && ! find_regno_note (insn, REG_DEAD, regno))
5845 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
5847 if (pbi->flags & PROP_REG_INFO)
5848 REG_N_DEATHS (regno)++;
5852 /* Don't make a REG_DEAD note for a part of a register
5853 that is set in the insn. */
5855 n = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)) - 1;
5856 for (; n >= regno; n--)
5857 if (! REGNO_REG_SET_P (pbi->reg_live, n)
5858 && ! dead_or_set_regno_p (insn, n))
5860 = alloc_EXPR_LIST (REG_DEAD,
5861 gen_rtx_REG (reg_raw_mode[n], n),
5866 SET_REGNO_REG_SET (pbi->reg_live, regno);
5867 if (regno < FIRST_PSEUDO_REGISTER)
5869 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5871 SET_REGNO_REG_SET (pbi->reg_live, regno + n);
5874 #ifdef HAVE_conditional_execution
5875 /* If this is a conditional use, record that fact. If it is later
5876 conditionally set, we'll know to kill the register. */
5877 if (cond != NULL_RTX)
5879 splay_tree_node node;
5880 struct reg_cond_life_info *rcli;
5885 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
5888 /* The register was unconditionally live previously.
5889 No need to do anything. */
5893 /* The register was conditionally live previously.
5894 Subtract the new life cond from the old death cond. */
5895 rcli = (struct reg_cond_life_info *) node->value;
5896 ncond = rcli->condition;
5897 ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
5899 /* If the register is now unconditionally live, remove the
5900 entry in the splay_tree. */
5901 if (ncond == const0_rtx)
5903 rcli->condition = NULL_RTX;
5904 splay_tree_remove (pbi->reg_cond_dead, regno);
5908 rcli->condition = ncond;
5909 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5915 /* The register was not previously live at all. Record
5916 the condition under which it is still dead. */
5917 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
5918 rcli->condition = not_reg_cond (cond);
5919 splay_tree_insert (pbi->reg_cond_dead, regno,
5920 (splay_tree_value) rcli);
5922 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5925 else if (some_was_live)
5927 splay_tree_node node;
5928 struct reg_cond_life_info *rcli;
5930 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
5933 /* The register was conditionally live previously, but is now
5934 unconditionally so. Remove it from the conditionally dead
5935 list, so that a conditional set won't cause us to think
5937 rcli = (struct reg_cond_life_info *) node->value;
5938 rcli->condition = NULL_RTX;
5939 splay_tree_remove (pbi->reg_cond_dead, regno);
5946 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
5947 This is done assuming the registers needed from X are those that
5948 have 1-bits in PBI->REG_LIVE.
5950 INSN is the containing instruction. If INSN is dead, this function
5954 mark_used_regs (pbi, x, cond, insn)
5955 struct propagate_block_info *pbi;
5958 register RTX_CODE code;
5960 int flags = pbi->flags;
5963 code = GET_CODE (x);
5983 /* If we are clobbering a MEM, mark any registers inside the address
5985 if (GET_CODE (XEXP (x, 0)) == MEM)
5986 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
5990 /* Don't bother watching stores to mems if this is not the
5991 final pass. We'll not be deleting dead stores this round. */
5992 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
5994 /* Invalidate the data for the last MEM stored, but only if MEM is
5995 something that can be stored into. */
5996 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
5997 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
5998 /* Needn't clear the memory set list. */
6002 rtx temp = pbi->mem_set_list;
6003 rtx prev = NULL_RTX;
6008 next = XEXP (temp, 1);
6009 if (anti_dependence (XEXP (temp, 0), x))
6011 /* Splice temp out of the list. */
6013 XEXP (prev, 1) = next;
6015 pbi->mem_set_list = next;
6016 free_EXPR_LIST_node (temp);
6017 pbi->mem_set_list_len--;
6025 /* If the memory reference had embedded side effects (autoincrement
6026 address modes. Then we may need to kill some entries on the
6029 invalidate_mems_from_autoinc (pbi, insn);
6033 if (flags & PROP_AUTOINC)
6034 find_auto_inc (pbi, x, insn);
6039 #ifdef CLASS_CANNOT_CHANGE_MODE
6040 if (GET_CODE (SUBREG_REG (x)) == REG
6041 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
6042 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
6043 GET_MODE (SUBREG_REG (x))))
6044 REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
6047 /* While we're here, optimize this case. */
6049 if (GET_CODE (x) != REG)
6054 /* See a register other than being set => mark it as needed. */
6055 mark_used_reg (pbi, x, cond, insn);
6060 register rtx testreg = SET_DEST (x);
6063 /* If storing into MEM, don't show it as being used. But do
6064 show the address as being used. */
6065 if (GET_CODE (testreg) == MEM)
6068 if (flags & PROP_AUTOINC)
6069 find_auto_inc (pbi, testreg, insn);
6071 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
6072 mark_used_regs (pbi, SET_SRC (x), cond, insn);
6076 /* Storing in STRICT_LOW_PART is like storing in a reg
6077 in that this SET might be dead, so ignore it in TESTREG.
6078 but in some other ways it is like using the reg.
6080 Storing in a SUBREG or a bit field is like storing the entire
6081 register in that if the register's value is not used
6082 then this SET is not needed. */
6083 while (GET_CODE (testreg) == STRICT_LOW_PART
6084 || GET_CODE (testreg) == ZERO_EXTRACT
6085 || GET_CODE (testreg) == SIGN_EXTRACT
6086 || GET_CODE (testreg) == SUBREG)
6088 #ifdef CLASS_CANNOT_CHANGE_MODE
6089 if (GET_CODE (testreg) == SUBREG
6090 && GET_CODE (SUBREG_REG (testreg)) == REG
6091 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
6092 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
6093 GET_MODE (testreg)))
6094 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
6097 /* Modifying a single register in an alternate mode
6098 does not use any of the old value. But these other
6099 ways of storing in a register do use the old value. */
6100 if (GET_CODE (testreg) == SUBREG
6101 && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
6106 testreg = XEXP (testreg, 0);
6109 /* If this is a store into a register or group of registers,
6110 recursively scan the value being stored. */
6112 if ((GET_CODE (testreg) == PARALLEL
6113 && GET_MODE (testreg) == BLKmode)
6114 || (GET_CODE (testreg) == REG
6115 && (regno = REGNO (testreg),
6116 ! (regno == FRAME_POINTER_REGNUM
6117 && (! reload_completed || frame_pointer_needed)))
6118 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
6119 && ! (regno == HARD_FRAME_POINTER_REGNUM
6120 && (! reload_completed || frame_pointer_needed))
6122 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
6123 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
6128 mark_used_regs (pbi, SET_DEST (x), cond, insn);
6129 mark_used_regs (pbi, SET_SRC (x), cond, insn);
6136 case UNSPEC_VOLATILE:
6140 /* Traditional and volatile asm instructions must be considered to use
6141 and clobber all hard registers, all pseudo-registers and all of
6142 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
6144 Consider for instance a volatile asm that changes the fpu rounding
6145 mode. An insn should not be moved across this even if it only uses
6146 pseudo-regs because it might give an incorrectly rounded result.
6148 ?!? Unfortunately, marking all hard registers as live causes massive
6149 problems for the register allocator and marking all pseudos as live
6150 creates mountains of uninitialized variable warnings.
6152 So for now, just clear the memory set list and mark any regs
6153 we can find in ASM_OPERANDS as used. */
6154 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
6156 free_EXPR_LIST_list (&pbi->mem_set_list);
6157 pbi->mem_set_list_len = 0;
6160 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
6161 We can not just fall through here since then we would be confused
6162 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
6163 traditional asms unlike their normal usage. */
6164 if (code == ASM_OPERANDS)
6168 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
6169 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
6175 if (cond != NULL_RTX)
6178 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
6180 cond = COND_EXEC_TEST (x);
6181 x = COND_EXEC_CODE (x);
6185 /* We _do_not_ want to scan operands of phi nodes. Operands of
6186 a phi function are evaluated only when control reaches this
6187 block along a particular edge. Therefore, regs that appear
6188 as arguments to phi should not be added to the global live at
6196 /* Recursively scan the operands of this expression. */
6199 register const char *fmt = GET_RTX_FORMAT (code);
6202 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
6206 /* Tail recursive case: save a function call level. */
6212 mark_used_regs (pbi, XEXP (x, i), cond, insn);
6214 else if (fmt[i] == 'E')
6217 for (j = 0; j < XVECLEN (x, i); j++)
6218 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
6227 try_pre_increment_1 (pbi, insn)
6228 struct propagate_block_info *pbi;
6231 /* Find the next use of this reg. If in same basic block,
6232 make it do pre-increment or pre-decrement if appropriate. */
6233 rtx x = single_set (insn);
6234 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
6235 * INTVAL (XEXP (SET_SRC (x), 1)));
6236 int regno = REGNO (SET_DEST (x));
6237 rtx y = pbi->reg_next_use[regno];
6239 && SET_DEST (x) != stack_pointer_rtx
6240 && BLOCK_NUM (y) == BLOCK_NUM (insn)
6241 /* Don't do this if the reg dies, or gets set in y; a standard addressing
6242 mode would be better. */
6243 && ! dead_or_set_p (y, SET_DEST (x))
6244 && try_pre_increment (y, SET_DEST (x), amount))
6246 /* We have found a suitable auto-increment and already changed
6247 insn Y to do it. So flush this increment instruction. */
6248 propagate_block_delete_insn (pbi->bb, insn);
6250 /* Count a reference to this reg for the increment insn we are
6251 deleting. When a reg is incremented, spilling it is worse,
6252 so we want to make that less likely. */
6253 if (regno >= FIRST_PSEUDO_REGISTER)
6255 REG_N_REFS (regno) += (optimize_size ? 1
6256 : pbi->bb->loop_depth + 1);
6257 REG_N_SETS (regno)++;
6260 /* Flush any remembered memories depending on the value of
6261 the incremented register. */
6262 invalidate_mems_from_set (pbi, SET_DEST (x));
6269 /* Try to change INSN so that it does pre-increment or pre-decrement
6270 addressing on register REG in order to add AMOUNT to REG.
6271 AMOUNT is negative for pre-decrement.
6272 Returns 1 if the change could be made.
6273 This checks all about the validity of the result of modifying INSN. */
6276 try_pre_increment (insn, reg, amount)
6278 HOST_WIDE_INT amount;
6282 /* Nonzero if we can try to make a pre-increment or pre-decrement.
6283 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
6285 /* Nonzero if we can try to make a post-increment or post-decrement.
6286 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
6287 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
6288 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
6291 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
6294 /* From the sign of increment, see which possibilities are conceivable
6295 on this target machine. */
6296 if (HAVE_PRE_INCREMENT && amount > 0)
6298 if (HAVE_POST_INCREMENT && amount > 0)
6301 if (HAVE_PRE_DECREMENT && amount < 0)
6303 if (HAVE_POST_DECREMENT && amount < 0)
6306 if (! (pre_ok || post_ok))
6309 /* It is not safe to add a side effect to a jump insn
6310 because if the incremented register is spilled and must be reloaded
6311 there would be no way to store the incremented value back in memory. */
6313 if (GET_CODE (insn) == JUMP_INSN)
6318 use = find_use_as_address (PATTERN (insn), reg, 0);
6319 if (post_ok && (use == 0 || use == (rtx) 1))
6321 use = find_use_as_address (PATTERN (insn), reg, -amount);
6325 if (use == 0 || use == (rtx) 1)
6328 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
6331 /* See if this combination of instruction and addressing mode exists. */
6332 if (! validate_change (insn, &XEXP (use, 0),
6333 gen_rtx_fmt_e (amount > 0
6334 ? (do_post ? POST_INC : PRE_INC)
6335 : (do_post ? POST_DEC : PRE_DEC),
6339 /* Record that this insn now has an implicit side effect on X. */
6340 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
6344 #endif /* AUTO_INC_DEC */
6346 /* Find the place in the rtx X where REG is used as a memory address.
6347 Return the MEM rtx that so uses it.
6348 If PLUSCONST is nonzero, search instead for a memory address equivalent to
6349 (plus REG (const_int PLUSCONST)).
6351 If such an address does not appear, return 0.
6352 If REG appears more than once, or is used other than in such an address,
6356 find_use_as_address (x, reg, plusconst)
6359 HOST_WIDE_INT plusconst;
6361 enum rtx_code code = GET_CODE (x);
6362 const char *fmt = GET_RTX_FORMAT (code);
6364 register rtx value = 0;
6367 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
6370 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
6371 && XEXP (XEXP (x, 0), 0) == reg
6372 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
6373 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
6376 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
6378 /* If REG occurs inside a MEM used in a bit-field reference,
6379 that is unacceptable. */
6380 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
6381 return (rtx) (HOST_WIDE_INT) 1;
6385 return (rtx) (HOST_WIDE_INT) 1;
6387 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
6391 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
6395 return (rtx) (HOST_WIDE_INT) 1;
6397 else if (fmt[i] == 'E')
6400 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
6402 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
6406 return (rtx) (HOST_WIDE_INT) 1;
6414 /* Write information about registers and basic blocks into FILE.
6415 This is part of making a debugging dump. */
6418 dump_regset (r, outf)
6425 fputs (" (nil)", outf);
6429 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
6431 fprintf (outf, " %d", i);
6432 if (i < FIRST_PSEUDO_REGISTER)
6433 fprintf (outf, " [%s]",
6442 dump_regset (r, stderr);
6443 putc ('\n', stderr);
6447 dump_flow_info (file)
6451 static const char * const reg_class_names[] = REG_CLASS_NAMES;
6453 fprintf (file, "%d registers.\n", max_regno);
6454 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
6457 enum reg_class class, altclass;
6458 fprintf (file, "\nRegister %d used %d times across %d insns",
6459 i, REG_N_REFS (i), REG_LIVE_LENGTH (i));
6460 if (REG_BASIC_BLOCK (i) >= 0)
6461 fprintf (file, " in block %d", REG_BASIC_BLOCK (i));
6463 fprintf (file, "; set %d time%s", REG_N_SETS (i),
6464 (REG_N_SETS (i) == 1) ? "" : "s");
6465 if (REG_USERVAR_P (regno_reg_rtx[i]))
6466 fprintf (file, "; user var");
6467 if (REG_N_DEATHS (i) != 1)
6468 fprintf (file, "; dies in %d places", REG_N_DEATHS (i));
6469 if (REG_N_CALLS_CROSSED (i) == 1)
6470 fprintf (file, "; crosses 1 call");
6471 else if (REG_N_CALLS_CROSSED (i))
6472 fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i));
6473 if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
6474 fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
6475 class = reg_preferred_class (i);
6476 altclass = reg_alternate_class (i);
6477 if (class != GENERAL_REGS || altclass != ALL_REGS)
6479 if (altclass == ALL_REGS || class == ALL_REGS)
6480 fprintf (file, "; pref %s", reg_class_names[(int) class]);
6481 else if (altclass == NO_REGS)
6482 fprintf (file, "; %s or none", reg_class_names[(int) class]);
6484 fprintf (file, "; pref %s, else %s",
6485 reg_class_names[(int) class],
6486 reg_class_names[(int) altclass]);
6488 if (REG_POINTER (regno_reg_rtx[i]))
6489 fprintf (file, "; pointer");
6490 fprintf (file, ".\n");
6493 fprintf (file, "\n%d basic blocks, %d edges.\n", n_basic_blocks, n_edges);
6494 for (i = 0; i < n_basic_blocks; i++)
6496 register basic_block bb = BASIC_BLOCK (i);
6499 fprintf (file, "\nBasic block %d: first insn %d, last %d, loop_depth %d, count %d.\n",
6500 i, INSN_UID (bb->head), INSN_UID (bb->end), bb->loop_depth, bb->count);
6502 fprintf (file, "Predecessors: ");
6503 for (e = bb->pred; e; e = e->pred_next)
6504 dump_edge_info (file, e, 0);
6506 fprintf (file, "\nSuccessors: ");
6507 for (e = bb->succ; e; e = e->succ_next)
6508 dump_edge_info (file, e, 1);
6510 fprintf (file, "\nRegisters live at start:");
6511 dump_regset (bb->global_live_at_start, file);
6513 fprintf (file, "\nRegisters live at end:");
6514 dump_regset (bb->global_live_at_end, file);
6525 dump_flow_info (stderr);
6529 dump_edge_info (file, e, do_succ)
6534 basic_block side = (do_succ ? e->dest : e->src);
6536 if (side == ENTRY_BLOCK_PTR)
6537 fputs (" ENTRY", file);
6538 else if (side == EXIT_BLOCK_PTR)
6539 fputs (" EXIT", file);
6541 fprintf (file, " %d", side->index);
6544 fprintf (file, " count:%d", e->count);
6548 static const char * const bitnames[] = {
6549 "fallthru", "crit", "ab", "abcall", "eh", "fake"
6552 int i, flags = e->flags;
6556 for (i = 0; flags; i++)
6557 if (flags & (1 << i))
6563 if (i < (int) ARRAY_SIZE (bitnames))
6564 fputs (bitnames[i], file);
6566 fprintf (file, "%d", i);
6573 /* Print out one basic block with live information at start and end. */
6584 fprintf (outf, ";; Basic block %d, loop depth %d, count %d",
6585 bb->index, bb->loop_depth, bb->count);
6586 if (bb->eh_beg != -1 || bb->eh_end != -1)
6587 fprintf (outf, ", eh regions %d/%d", bb->eh_beg, bb->eh_end);
6590 fputs (";; Predecessors: ", outf);
6591 for (e = bb->pred; e; e = e->pred_next)
6592 dump_edge_info (outf, e, 0);
6595 fputs (";; Registers live at start:", outf);
6596 dump_regset (bb->global_live_at_start, outf);
6599 for (insn = bb->head, last = NEXT_INSN (bb->end);
6601 insn = NEXT_INSN (insn))
6602 print_rtl_single (outf, insn);
6604 fputs (";; Registers live at end:", outf);
6605 dump_regset (bb->global_live_at_end, outf);
6608 fputs (";; Successors: ", outf);
6609 for (e = bb->succ; e; e = e->succ_next)
6610 dump_edge_info (outf, e, 1);
6618 dump_bb (bb, stderr);
6625 dump_bb (BASIC_BLOCK (n), stderr);
6628 /* Like print_rtl, but also print out live information for the start of each
6632 print_rtl_with_bb (outf, rtx_first)
6636 register rtx tmp_rtx;
6639 fprintf (outf, "(nil)\n");
6643 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
6644 int max_uid = get_max_uid ();
6645 basic_block *start = (basic_block *)
6646 xcalloc (max_uid, sizeof (basic_block));
6647 basic_block *end = (basic_block *)
6648 xcalloc (max_uid, sizeof (basic_block));
6649 enum bb_state *in_bb_p = (enum bb_state *)
6650 xcalloc (max_uid, sizeof (enum bb_state));
6652 for (i = n_basic_blocks - 1; i >= 0; i--)
6654 basic_block bb = BASIC_BLOCK (i);
6657 start[INSN_UID (bb->head)] = bb;
6658 end[INSN_UID (bb->end)] = bb;
6659 for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x))
6661 enum bb_state state = IN_MULTIPLE_BB;
6662 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
6664 in_bb_p[INSN_UID (x)] = state;
6671 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
6676 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
6678 fprintf (outf, ";; Start of basic block %d, registers live:",
6680 dump_regset (bb->global_live_at_start, outf);
6684 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
6685 && GET_CODE (tmp_rtx) != NOTE
6686 && GET_CODE (tmp_rtx) != BARRIER)
6687 fprintf (outf, ";; Insn is not within a basic block\n");
6688 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
6689 fprintf (outf, ";; Insn is in multiple basic blocks\n");
6691 did_output = print_rtl_single (outf, tmp_rtx);
6693 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
6695 fprintf (outf, ";; End of basic block %d, registers live:\n",
6697 dump_regset (bb->global_live_at_end, outf);
6710 if (current_function_epilogue_delay_list != 0)
6712 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
6713 for (tmp_rtx = current_function_epilogue_delay_list; tmp_rtx != 0;
6714 tmp_rtx = XEXP (tmp_rtx, 1))
6715 print_rtl_single (outf, XEXP (tmp_rtx, 0));
6719 /* Dump the rtl into the current debugging dump file, then abort. */
6722 print_rtl_and_abort_fcn (file, line, function)
6725 const char *function;
6729 print_rtl_with_bb (rtl_dump_file, get_insns ());
6730 fclose (rtl_dump_file);
6733 fancy_abort (file, line, function);
6736 /* Recompute register set/reference counts immediately prior to register
6739 This avoids problems with set/reference counts changing to/from values
6740 which have special meanings to the register allocators.
6742 Additionally, the reference counts are the primary component used by the
6743 register allocators to prioritize pseudos for allocation to hard regs.
6744 More accurate reference counts generally lead to better register allocation.
6746 F is the first insn to be scanned.
6748 LOOP_STEP denotes how much loop_depth should be incremented per
6749 loop nesting level in order to increase the ref count more for
6750 references in a loop.
6752 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
6753 possibly other information which is used by the register allocators. */
6756 recompute_reg_usage (f, loop_step)
6757 rtx f ATTRIBUTE_UNUSED;
6758 int loop_step ATTRIBUTE_UNUSED;
6760 allocate_reg_life_data ();
6761 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
6764 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
6765 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
6766 of the number of registers that died. */
6769 count_or_remove_death_notes (blocks, kill)
6775 for (i = n_basic_blocks - 1; i >= 0; --i)
6780 if (blocks && ! TEST_BIT (blocks, i))
6783 bb = BASIC_BLOCK (i);
6785 for (insn = bb->head;; insn = NEXT_INSN (insn))
6789 rtx *pprev = ®_NOTES (insn);
6794 switch (REG_NOTE_KIND (link))
6797 if (GET_CODE (XEXP (link, 0)) == REG)
6799 rtx reg = XEXP (link, 0);
6802 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
6805 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
6813 rtx next = XEXP (link, 1);
6814 free_EXPR_LIST_node (link);
6815 *pprev = link = next;
6821 pprev = &XEXP (link, 1);
6828 if (insn == bb->end)
6837 /* Update insns block within BB. */
6840 update_bb_for_insn (bb)
6845 if (! basic_block_for_insn)
6848 for (insn = bb->head; ; insn = NEXT_INSN (insn))
6850 set_block_for_insn (insn, bb);
6852 if (insn == bb->end)
6858 /* Record INSN's block as BB. */
6861 set_block_for_insn (insn, bb)
6865 size_t uid = INSN_UID (insn);
6866 if (uid >= basic_block_for_insn->num_elements)
6870 /* Add one-eighth the size so we don't keep calling xrealloc. */
6871 new_size = uid + (uid + 7) / 8;
6873 VARRAY_GROW (basic_block_for_insn, new_size);
6875 VARRAY_BB (basic_block_for_insn, uid) = bb;
6878 /* Record INSN's block number as BB. */
6879 /* ??? This has got to go. */
6882 set_block_num (insn, bb)
6886 set_block_for_insn (insn, BASIC_BLOCK (bb));
6889 /* Verify the CFG consistency. This function check some CFG invariants and
6890 aborts when something is wrong. Hope that this function will help to
6891 convert many optimization passes to preserve CFG consistent.
6893 Currently it does following checks:
6895 - test head/end pointers
6896 - overlapping of basic blocks
6897 - edge list corectness
6898 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
6899 - tails of basic blocks (ensure that boundary is necesary)
6900 - scans body of the basic block for JUMP_INSN, CODE_LABEL
6901 and NOTE_INSN_BASIC_BLOCK
6902 - check that all insns are in the basic blocks
6903 (except the switch handling code, barriers and notes)
6904 - check that all returns are followed by barriers
6906 In future it can be extended check a lot of other stuff as well
6907 (reachability of basic blocks, life information, etc. etc.). */
6912 const int max_uid = get_max_uid ();
6913 const rtx rtx_first = get_insns ();
6914 rtx last_head = get_last_insn ();
6915 basic_block *bb_info;
6917 int i, last_bb_num_seen, num_bb_notes, err = 0;
6919 bb_info = (basic_block *) xcalloc (max_uid, sizeof (basic_block));
6921 for (i = n_basic_blocks - 1; i >= 0; i--)
6923 basic_block bb = BASIC_BLOCK (i);
6924 rtx head = bb->head;
6927 /* Verify the end of the basic block is in the INSN chain. */
6928 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
6933 error ("End insn %d for block %d not found in the insn stream.",
6934 INSN_UID (end), bb->index);
6938 /* Work backwards from the end to the head of the basic block
6939 to verify the head is in the RTL chain. */
6940 for (; x != NULL_RTX; x = PREV_INSN (x))
6942 /* While walking over the insn chain, verify insns appear
6943 in only one basic block and initialize the BB_INFO array
6944 used by other passes. */
6945 if (bb_info[INSN_UID (x)] != NULL)
6947 error ("Insn %d is in multiple basic blocks (%d and %d)",
6948 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
6951 bb_info[INSN_UID (x)] = bb;
6958 error ("Head insn %d for block %d not found in the insn stream.",
6959 INSN_UID (head), bb->index);
6966 /* Now check the basic blocks (boundaries etc.) */
6967 for (i = n_basic_blocks - 1; i >= 0; i--)
6969 basic_block bb = BASIC_BLOCK (i);
6970 /* Check corectness of edge lists */
6979 "verify_flow_info: Basic block %d succ edge is corrupted\n",
6981 fprintf (stderr, "Predecessor: ");
6982 dump_edge_info (stderr, e, 0);
6983 fprintf (stderr, "\nSuccessor: ");
6984 dump_edge_info (stderr, e, 1);
6988 if (e->dest != EXIT_BLOCK_PTR)
6990 edge e2 = e->dest->pred;
6991 while (e2 && e2 != e)
6995 error ("Basic block %i edge lists are corrupted", bb->index);
7007 error ("Basic block %d pred edge is corrupted", bb->index);
7008 fputs ("Predecessor: ", stderr);
7009 dump_edge_info (stderr, e, 0);
7010 fputs ("\nSuccessor: ", stderr);
7011 dump_edge_info (stderr, e, 1);
7012 fputc ('\n', stderr);
7015 if (e->src != ENTRY_BLOCK_PTR)
7017 edge e2 = e->src->succ;
7018 while (e2 && e2 != e)
7022 error ("Basic block %i edge lists are corrupted", bb->index);
7029 /* OK pointers are correct. Now check the header of basic
7030 block. It ought to contain optional CODE_LABEL followed
7031 by NOTE_BASIC_BLOCK. */
7033 if (GET_CODE (x) == CODE_LABEL)
7037 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
7043 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
7045 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d\n",
7052 /* Do checks for empty blocks here */
7059 if (NOTE_INSN_BASIC_BLOCK_P (x))
7061 error ("NOTE_INSN_BASIC_BLOCK %d in the middle of basic block %d",
7062 INSN_UID (x), bb->index);
7069 if (GET_CODE (x) == JUMP_INSN
7070 || GET_CODE (x) == CODE_LABEL
7071 || GET_CODE (x) == BARRIER)
7073 error ("In basic block %d:", bb->index);
7074 fatal_insn ("Flow control insn inside a basic block", x);
7082 last_bb_num_seen = -1;
7087 if (NOTE_INSN_BASIC_BLOCK_P (x))
7089 basic_block bb = NOTE_BASIC_BLOCK (x);
7091 if (bb->index != last_bb_num_seen + 1)
7092 /* Basic blocks not numbered consecutively. */
7095 last_bb_num_seen = bb->index;
7098 if (!bb_info[INSN_UID (x)])
7100 switch (GET_CODE (x))
7107 /* An addr_vec is placed outside any block block. */
7109 && GET_CODE (NEXT_INSN (x)) == JUMP_INSN
7110 && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
7111 || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
7116 /* But in any case, non-deletable labels can appear anywhere. */
7120 fatal_insn ("Insn outside basic block", x);
7125 && GET_CODE (x) == JUMP_INSN
7126 && returnjump_p (x) && ! condjump_p (x)
7127 && ! (NEXT_INSN (x) && GET_CODE (NEXT_INSN (x)) == BARRIER))
7128 fatal_insn ("Return not followed by barrier", x);
7133 if (num_bb_notes != n_basic_blocks)
7135 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
7136 num_bb_notes, n_basic_blocks);
7145 /* Functions to access an edge list with a vector representation.
7146 Enough data is kept such that given an index number, the
7147 pred and succ that edge represents can be determined, or
7148 given a pred and a succ, its index number can be returned.
7149 This allows algorithms which consume a lot of memory to
7150 represent the normally full matrix of edge (pred,succ) with a
7151 single indexed vector, edge (EDGE_INDEX (pred, succ)), with no
7152 wasted space in the client code due to sparse flow graphs. */
7154 /* This functions initializes the edge list. Basically the entire
7155 flowgraph is processed, and all edges are assigned a number,
7156 and the data structure is filled in. */
7161 struct edge_list *elist;
7167 block_count = n_basic_blocks + 2; /* Include the entry and exit blocks. */
7171 /* Determine the number of edges in the flow graph by counting successor
7172 edges on each basic block. */
7173 for (x = 0; x < n_basic_blocks; x++)
7175 basic_block bb = BASIC_BLOCK (x);
7177 for (e = bb->succ; e; e = e->succ_next)
7180 /* Don't forget successors of the entry block. */
7181 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
7184 elist = (struct edge_list *) xmalloc (sizeof (struct edge_list));
7185 elist->num_blocks = block_count;
7186 elist->num_edges = num_edges;
7187 elist->index_to_edge = (edge *) xmalloc (sizeof (edge) * num_edges);
7191 /* Follow successors of the entry block, and register these edges. */
7192 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
7194 elist->index_to_edge[num_edges] = e;
7198 for (x = 0; x < n_basic_blocks; x++)
7200 basic_block bb = BASIC_BLOCK (x);
7202 /* Follow all successors of blocks, and register these edges. */
7203 for (e = bb->succ; e; e = e->succ_next)
7205 elist->index_to_edge[num_edges] = e;
7212 /* This function free's memory associated with an edge list. */
7215 free_edge_list (elist)
7216 struct edge_list *elist;
7220 free (elist->index_to_edge);
7225 /* This function provides debug output showing an edge list. */
7228 print_edge_list (f, elist)
7230 struct edge_list *elist;
7233 fprintf (f, "Compressed edge list, %d BBs + entry & exit, and %d edges\n",
7234 elist->num_blocks - 2, elist->num_edges);
7236 for (x = 0; x < elist->num_edges; x++)
7238 fprintf (f, " %-4d - edge(", x);
7239 if (INDEX_EDGE_PRED_BB (elist, x) == ENTRY_BLOCK_PTR)
7240 fprintf (f, "entry,");
7242 fprintf (f, "%d,", INDEX_EDGE_PRED_BB (elist, x)->index);
7244 if (INDEX_EDGE_SUCC_BB (elist, x) == EXIT_BLOCK_PTR)
7245 fprintf (f, "exit)\n");
7247 fprintf (f, "%d)\n", INDEX_EDGE_SUCC_BB (elist, x)->index);
7251 /* This function provides an internal consistency check of an edge list,
7252 verifying that all edges are present, and that there are no
7256 verify_edge_list (f, elist)
7258 struct edge_list *elist;
7260 int x, pred, succ, index;
7263 for (x = 0; x < n_basic_blocks; x++)
7265 basic_block bb = BASIC_BLOCK (x);
7267 for (e = bb->succ; e; e = e->succ_next)
7269 pred = e->src->index;
7270 succ = e->dest->index;
7271 index = EDGE_INDEX (elist, e->src, e->dest);
7272 if (index == EDGE_INDEX_NO_EDGE)
7274 fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
7277 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
7278 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
7279 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
7280 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
7281 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
7282 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
7285 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
7287 pred = e->src->index;
7288 succ = e->dest->index;
7289 index = EDGE_INDEX (elist, e->src, e->dest);
7290 if (index == EDGE_INDEX_NO_EDGE)
7292 fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
7295 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
7296 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
7297 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
7298 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
7299 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
7300 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
7302 /* We've verified that all the edges are in the list, no lets make sure
7303 there are no spurious edges in the list. */
7305 for (pred = 0; pred < n_basic_blocks; pred++)
7306 for (succ = 0; succ < n_basic_blocks; succ++)
7308 basic_block p = BASIC_BLOCK (pred);
7309 basic_block s = BASIC_BLOCK (succ);
7313 for (e = p->succ; e; e = e->succ_next)
7319 for (e = s->pred; e; e = e->pred_next)
7325 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
7326 == EDGE_INDEX_NO_EDGE && found_edge != 0)
7327 fprintf (f, "*** Edge (%d, %d) appears to not have an index\n",
7329 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
7330 != EDGE_INDEX_NO_EDGE && found_edge == 0)
7331 fprintf (f, "*** Edge (%d, %d) has index %d, but there is no edge\n",
7332 pred, succ, EDGE_INDEX (elist, BASIC_BLOCK (pred),
7333 BASIC_BLOCK (succ)));
7335 for (succ = 0; succ < n_basic_blocks; succ++)
7337 basic_block p = ENTRY_BLOCK_PTR;
7338 basic_block s = BASIC_BLOCK (succ);
7342 for (e = p->succ; e; e = e->succ_next)
7348 for (e = s->pred; e; e = e->pred_next)
7354 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
7355 == EDGE_INDEX_NO_EDGE && found_edge != 0)
7356 fprintf (f, "*** Edge (entry, %d) appears to not have an index\n",
7358 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
7359 != EDGE_INDEX_NO_EDGE && found_edge == 0)
7360 fprintf (f, "*** Edge (entry, %d) has index %d, but no edge exists\n",
7361 succ, EDGE_INDEX (elist, ENTRY_BLOCK_PTR,
7362 BASIC_BLOCK (succ)));
7364 for (pred = 0; pred < n_basic_blocks; pred++)
7366 basic_block p = BASIC_BLOCK (pred);
7367 basic_block s = EXIT_BLOCK_PTR;
7371 for (e = p->succ; e; e = e->succ_next)
7377 for (e = s->pred; e; e = e->pred_next)
7383 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
7384 == EDGE_INDEX_NO_EDGE && found_edge != 0)
7385 fprintf (f, "*** Edge (%d, exit) appears to not have an index\n",
7387 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
7388 != EDGE_INDEX_NO_EDGE && found_edge == 0)
7389 fprintf (f, "*** Edge (%d, exit) has index %d, but no edge exists\n",
7390 pred, EDGE_INDEX (elist, BASIC_BLOCK (pred),
7395 /* This routine will determine what, if any, edge there is between
7396 a specified predecessor and successor. */
7399 find_edge_index (edge_list, pred, succ)
7400 struct edge_list *edge_list;
7401 basic_block pred, succ;
7404 for (x = 0; x < NUM_EDGES (edge_list); x++)
7406 if (INDEX_EDGE_PRED_BB (edge_list, x) == pred
7407 && INDEX_EDGE_SUCC_BB (edge_list, x) == succ)
7410 return (EDGE_INDEX_NO_EDGE);
7413 /* This function will remove an edge from the flow graph. */
7419 edge last_pred = NULL;
7420 edge last_succ = NULL;
7422 basic_block src, dest;
7425 for (tmp = src->succ; tmp && tmp != e; tmp = tmp->succ_next)
7431 last_succ->succ_next = e->succ_next;
7433 src->succ = e->succ_next;
7435 for (tmp = dest->pred; tmp && tmp != e; tmp = tmp->pred_next)
7441 last_pred->pred_next = e->pred_next;
7443 dest->pred = e->pred_next;
7449 /* This routine will remove any fake successor edges for a basic block.
7450 When the edge is removed, it is also removed from whatever predecessor
7454 remove_fake_successors (bb)
7458 for (e = bb->succ; e;)
7462 if ((tmp->flags & EDGE_FAKE) == EDGE_FAKE)
7467 /* This routine will remove all fake edges from the flow graph. If
7468 we remove all fake successors, it will automatically remove all
7469 fake predecessors. */
7472 remove_fake_edges ()
7476 for (x = 0; x < n_basic_blocks; x++)
7477 remove_fake_successors (BASIC_BLOCK (x));
7479 /* We've handled all successors except the entry block's. */
7480 remove_fake_successors (ENTRY_BLOCK_PTR);
7483 /* This function will add a fake edge between any block which has no
7484 successors, and the exit block. Some data flow equations require these
7488 add_noreturn_fake_exit_edges ()
7492 for (x = 0; x < n_basic_blocks; x++)
7493 if (BASIC_BLOCK (x)->succ == NULL)
7494 make_edge (NULL, BASIC_BLOCK (x), EXIT_BLOCK_PTR, EDGE_FAKE);
7497 /* This function adds a fake edge between any infinite loops to the
7498 exit block. Some optimizations require a path from each node to
7501 See also Morgan, Figure 3.10, pp. 82-83.
7503 The current implementation is ugly, not attempting to minimize the
7504 number of inserted fake edges. To reduce the number of fake edges
7505 to insert, add fake edges from _innermost_ loops containing only
7506 nodes not reachable from the exit block. */
7509 connect_infinite_loops_to_exit ()
7511 basic_block unvisited_block;
7513 /* Perform depth-first search in the reverse graph to find nodes
7514 reachable from the exit block. */
7515 struct depth_first_search_dsS dfs_ds;
7517 flow_dfs_compute_reverse_init (&dfs_ds);
7518 flow_dfs_compute_reverse_add_bb (&dfs_ds, EXIT_BLOCK_PTR);
7520 /* Repeatedly add fake edges, updating the unreachable nodes. */
7523 unvisited_block = flow_dfs_compute_reverse_execute (&dfs_ds);
7524 if (!unvisited_block)
7526 make_edge (NULL, unvisited_block, EXIT_BLOCK_PTR, EDGE_FAKE);
7527 flow_dfs_compute_reverse_add_bb (&dfs_ds, unvisited_block);
7530 flow_dfs_compute_reverse_finish (&dfs_ds);
7535 /* Redirect an edge's successor from one block to another. */
7538 redirect_edge_succ (e, new_succ)
7540 basic_block new_succ;
7544 /* Disconnect the edge from the old successor block. */
7545 for (pe = &e->dest->pred; *pe != e; pe = &(*pe)->pred_next)
7547 *pe = (*pe)->pred_next;
7549 /* Reconnect the edge to the new successor block. */
7550 e->pred_next = new_succ->pred;
7555 /* Redirect an edge's predecessor from one block to another. */
7558 redirect_edge_pred (e, new_pred)
7560 basic_block new_pred;
7564 /* Disconnect the edge from the old predecessor block. */
7565 for (pe = &e->src->succ; *pe != e; pe = &(*pe)->succ_next)
7567 *pe = (*pe)->succ_next;
7569 /* Reconnect the edge to the new predecessor block. */
7570 e->succ_next = new_pred->succ;
7575 /* Dump the list of basic blocks in the bitmap NODES. */
7578 flow_nodes_print (str, nodes, file)
7580 const sbitmap nodes;
7588 fprintf (file, "%s { ", str);
7589 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {fprintf (file, "%d ", node);});
7590 fputs ("}\n", file);
7594 /* Dump the list of edges in the array EDGE_LIST. */
7597 flow_edge_list_print (str, edge_list, num_edges, file)
7599 const edge *edge_list;
7608 fprintf (file, "%s { ", str);
7609 for (i = 0; i < num_edges; i++)
7610 fprintf (file, "%d->%d ", edge_list[i]->src->index,
7611 edge_list[i]->dest->index);
7612 fputs ("}\n", file);
7616 /* Dump loop related CFG information. */
7619 flow_loops_cfg_dump (loops, file)
7620 const struct loops *loops;
7625 if (! loops->num || ! file || ! loops->cfg.dom)
7628 for (i = 0; i < n_basic_blocks; i++)
7632 fprintf (file, ";; %d succs { ", i);
7633 for (succ = BASIC_BLOCK (i)->succ; succ; succ = succ->succ_next)
7634 fprintf (file, "%d ", succ->dest->index);
7635 flow_nodes_print ("} dom", loops->cfg.dom[i], file);
7638 /* Dump the DFS node order. */
7639 if (loops->cfg.dfs_order)
7641 fputs (";; DFS order: ", file);
7642 for (i = 0; i < n_basic_blocks; i++)
7643 fprintf (file, "%d ", loops->cfg.dfs_order[i]);
7646 /* Dump the reverse completion node order. */
7647 if (loops->cfg.rc_order)
7649 fputs (";; RC order: ", file);
7650 for (i = 0; i < n_basic_blocks; i++)
7651 fprintf (file, "%d ", loops->cfg.rc_order[i]);
7656 /* Return non-zero if the nodes of LOOP are a subset of OUTER. */
7659 flow_loop_nested_p (outer, loop)
7663 return sbitmap_a_subset_b_p (loop->nodes, outer->nodes);
7667 /* Dump the loop information specified by LOOP to the stream FILE
7668 using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
7670 flow_loop_dump (loop, file, loop_dump_aux, verbose)
7671 const struct loop *loop;
7673 void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
7676 if (! loop || ! loop->header)
7679 fprintf (file, ";;\n;; Loop %d (%d to %d):%s%s\n",
7680 loop->num, INSN_UID (loop->first->head),
7681 INSN_UID (loop->last->end),
7682 loop->shared ? " shared" : "",
7683 loop->invalid ? " invalid" : "");
7684 fprintf (file, ";; header %d, latch %d, pre-header %d, first %d, last %d\n",
7685 loop->header->index, loop->latch->index,
7686 loop->pre_header ? loop->pre_header->index : -1,
7687 loop->first->index, loop->last->index);
7688 fprintf (file, ";; depth %d, level %d, outer %ld\n",
7689 loop->depth, loop->level,
7690 (long) (loop->outer ? loop->outer->num : -1));
7692 if (loop->pre_header_edges)
7693 flow_edge_list_print (";; pre-header edges", loop->pre_header_edges,
7694 loop->num_pre_header_edges, file);
7695 flow_edge_list_print (";; entry edges", loop->entry_edges,
7696 loop->num_entries, file);
7697 fprintf (file, ";; %d", loop->num_nodes);
7698 flow_nodes_print (" nodes", loop->nodes, file);
7699 flow_edge_list_print (";; exit edges", loop->exit_edges,
7700 loop->num_exits, file);
7701 if (loop->exits_doms)
7702 flow_nodes_print (";; exit doms", loop->exits_doms, file);
7704 loop_dump_aux (loop, file, verbose);
7708 /* Dump the loop information specified by LOOPS to the stream FILE,
7709 using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
7711 flow_loops_dump (loops, file, loop_dump_aux, verbose)
7712 const struct loops *loops;
7714 void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
7720 num_loops = loops->num;
7721 if (! num_loops || ! file)
7724 fprintf (file, ";; %d loops found, %d levels\n",
7725 num_loops, loops->levels);
7727 for (i = 0; i < num_loops; i++)
7729 struct loop *loop = &loops->array[i];
7731 flow_loop_dump (loop, file, loop_dump_aux, verbose);
7737 for (j = 0; j < i; j++)
7739 struct loop *oloop = &loops->array[j];
7741 if (loop->header == oloop->header)
7746 smaller = loop->num_nodes < oloop->num_nodes;
7748 /* If the union of LOOP and OLOOP is different than
7749 the larger of LOOP and OLOOP then LOOP and OLOOP
7750 must be disjoint. */
7751 disjoint = ! flow_loop_nested_p (smaller ? loop : oloop,
7752 smaller ? oloop : loop);
7754 ";; loop header %d shared by loops %d, %d %s\n",
7755 loop->header->index, i, j,
7756 disjoint ? "disjoint" : "nested");
7763 flow_loops_cfg_dump (loops, file);
7767 /* Free all the memory allocated for LOOPS. */
7770 flow_loops_free (loops)
7771 struct loops *loops;
7780 /* Free the loop descriptors. */
7781 for (i = 0; i < loops->num; i++)
7783 struct loop *loop = &loops->array[i];
7785 if (loop->pre_header_edges)
7786 free (loop->pre_header_edges);
7788 sbitmap_free (loop->nodes);
7789 if (loop->entry_edges)
7790 free (loop->entry_edges);
7791 if (loop->exit_edges)
7792 free (loop->exit_edges);
7793 if (loop->exits_doms)
7794 sbitmap_free (loop->exits_doms);
7796 free (loops->array);
7797 loops->array = NULL;
7800 sbitmap_vector_free (loops->cfg.dom);
7801 if (loops->cfg.dfs_order)
7802 free (loops->cfg.dfs_order);
7804 if (loops->shared_headers)
7805 sbitmap_free (loops->shared_headers);
7810 /* Find the entry edges into the loop with header HEADER and nodes
7811 NODES and store in ENTRY_EDGES array. Return the number of entry
7812 edges from the loop. */
7815 flow_loop_entry_edges_find (header, nodes, entry_edges)
7817 const sbitmap nodes;
7823 *entry_edges = NULL;
7826 for (e = header->pred; e; e = e->pred_next)
7828 basic_block src = e->src;
7830 if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
7837 *entry_edges = (edge *) xmalloc (num_entries * sizeof (edge *));
7840 for (e = header->pred; e; e = e->pred_next)
7842 basic_block src = e->src;
7844 if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
7845 (*entry_edges)[num_entries++] = e;
7852 /* Find the exit edges from the loop using the bitmap of loop nodes
7853 NODES and store in EXIT_EDGES array. Return the number of
7854 exit edges from the loop. */
7857 flow_loop_exit_edges_find (nodes, exit_edges)
7858 const sbitmap nodes;
7867 /* Check all nodes within the loop to see if there are any
7868 successors not in the loop. Note that a node may have multiple
7869 exiting edges ????? A node can have one jumping edge and one fallthru
7870 edge so only one of these can exit the loop. */
7872 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
7873 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
7875 basic_block dest = e->dest;
7877 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
7885 *exit_edges = (edge *) xmalloc (num_exits * sizeof (edge *));
7887 /* Store all exiting edges into an array. */
7889 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
7890 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
7892 basic_block dest = e->dest;
7894 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
7895 (*exit_edges)[num_exits++] = e;
7903 /* Find the nodes contained within the loop with header HEADER and
7904 latch LATCH and store in NODES. Return the number of nodes within
7908 flow_loop_nodes_find (header, latch, nodes)
7917 stack = (basic_block *) xmalloc (n_basic_blocks * sizeof (basic_block));
7920 /* Start with only the loop header in the set of loop nodes. */
7921 sbitmap_zero (nodes);
7922 SET_BIT (nodes, header->index);
7924 header->loop_depth++;
7926 /* Push the loop latch on to the stack. */
7927 if (! TEST_BIT (nodes, latch->index))
7929 SET_BIT (nodes, latch->index);
7930 latch->loop_depth++;
7932 stack[sp++] = latch;
7941 for (e = node->pred; e; e = e->pred_next)
7943 basic_block ancestor = e->src;
7945 /* If each ancestor not marked as part of loop, add to set of
7946 loop nodes and push on to stack. */
7947 if (ancestor != ENTRY_BLOCK_PTR
7948 && ! TEST_BIT (nodes, ancestor->index))
7950 SET_BIT (nodes, ancestor->index);
7951 ancestor->loop_depth++;
7953 stack[sp++] = ancestor;
7961 /* Compute the depth first search order and store in the array
7962 DFS_ORDER if non-zero, marking the nodes visited in VISITED. If
7963 RC_ORDER is non-zero, return the reverse completion number for each
7964 node. Returns the number of nodes visited. A depth first search
7965 tries to get as far away from the starting point as quickly as
7969 flow_depth_first_order_compute (dfs_order, rc_order)
7976 int rcnum = n_basic_blocks - 1;
7979 /* Allocate stack for back-tracking up CFG. */
7980 stack = (edge *) xmalloc ((n_basic_blocks + 1) * sizeof (edge));
7983 /* Allocate bitmap to track nodes that have been visited. */
7984 visited = sbitmap_alloc (n_basic_blocks);
7986 /* None of the nodes in the CFG have been visited yet. */
7987 sbitmap_zero (visited);
7989 /* Push the first edge on to the stack. */
7990 stack[sp++] = ENTRY_BLOCK_PTR->succ;
7998 /* Look at the edge on the top of the stack. */
8003 /* Check if the edge destination has been visited yet. */
8004 if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index))
8006 /* Mark that we have visited the destination. */
8007 SET_BIT (visited, dest->index);
8010 dfs_order[dfsnum++] = dest->index;
8014 /* Since the DEST node has been visited for the first
8015 time, check its successors. */
8016 stack[sp++] = dest->succ;
8020 /* There are no successors for the DEST node so assign
8021 its reverse completion number. */
8023 rc_order[rcnum--] = dest->index;
8028 if (! e->succ_next && src != ENTRY_BLOCK_PTR)
8030 /* There are no more successors for the SRC node
8031 so assign its reverse completion number. */
8033 rc_order[rcnum--] = src->index;
8037 stack[sp - 1] = e->succ_next;
8044 sbitmap_free (visited);
8046 /* The number of nodes visited should not be greater than
8048 if (dfsnum > n_basic_blocks)
8051 /* There are some nodes left in the CFG that are unreachable. */
8052 if (dfsnum < n_basic_blocks)
8057 /* Compute the depth first search order on the _reverse_ graph and
8058 store in the array DFS_ORDER, marking the nodes visited in VISITED.
8059 Returns the number of nodes visited.
8061 The computation is split into three pieces:
8063 flow_dfs_compute_reverse_init () creates the necessary data
8066 flow_dfs_compute_reverse_add_bb () adds a basic block to the data
8067 structures. The block will start the search.
8069 flow_dfs_compute_reverse_execute () continues (or starts) the
8070 search using the block on the top of the stack, stopping when the
8073 flow_dfs_compute_reverse_finish () destroys the necessary data
8076 Thus, the user will probably call ..._init(), call ..._add_bb() to
8077 add a beginning basic block to the stack, call ..._execute(),
8078 possibly add another bb to the stack and again call ..._execute(),
8079 ..., and finally call _finish(). */
8081 /* Initialize the data structures used for depth-first search on the
8082 reverse graph. If INITIALIZE_STACK is nonzero, the exit block is
8083 added to the basic block stack. DATA is the current depth-first
8084 search context. If INITIALIZE_STACK is non-zero, there is an
8085 element on the stack. */
8088 flow_dfs_compute_reverse_init (data)
8089 depth_first_search_ds data;
8091 /* Allocate stack for back-tracking up CFG. */
8093 (basic_block *) xmalloc ((n_basic_blocks - (INVALID_BLOCK + 1))
8094 * sizeof (basic_block));
8097 /* Allocate bitmap to track nodes that have been visited. */
8098 data->visited_blocks = sbitmap_alloc (n_basic_blocks - (INVALID_BLOCK + 1));
8100 /* None of the nodes in the CFG have been visited yet. */
8101 sbitmap_zero (data->visited_blocks);
8106 /* Add the specified basic block to the top of the dfs data
8107 structures. When the search continues, it will start at the
8111 flow_dfs_compute_reverse_add_bb (data, bb)
8112 depth_first_search_ds data;
8115 data->stack[data->sp++] = bb;
8119 /* Continue the depth-first search through the reverse graph starting
8120 with the block at the stack's top and ending when the stack is
8121 empty. Visited nodes are marked. Returns an unvisited basic
8122 block, or NULL if there is none available. */
8125 flow_dfs_compute_reverse_execute (data)
8126 depth_first_search_ds data;
8132 while (data->sp > 0)
8134 bb = data->stack[--data->sp];
8136 /* Mark that we have visited this node. */
8137 if (!TEST_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1)))
8139 SET_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1));
8141 /* Perform depth-first search on adjacent vertices. */
8142 for (e = bb->pred; e; e = e->pred_next)
8143 flow_dfs_compute_reverse_add_bb (data, e->src);
8147 /* Determine if there are unvisited basic blocks. */
8148 for (i = n_basic_blocks - (INVALID_BLOCK + 1); --i >= 0;)
8149 if (!TEST_BIT (data->visited_blocks, i))
8150 return BASIC_BLOCK (i + (INVALID_BLOCK + 1));
8154 /* Destroy the data structures needed for depth-first search on the
8158 flow_dfs_compute_reverse_finish (data)
8159 depth_first_search_ds data;
8162 sbitmap_free (data->visited_blocks);
8167 /* Find the root node of the loop pre-header extended basic block and
8168 the edges along the trace from the root node to the loop header. */
8171 flow_loop_pre_header_scan (loop)
8177 loop->num_pre_header_edges = 0;
8179 if (loop->num_entries != 1)
8182 ebb = loop->entry_edges[0]->src;
8184 if (ebb != ENTRY_BLOCK_PTR)
8188 /* Count number of edges along trace from loop header to
8189 root of pre-header extended basic block. Usually this is
8190 only one or two edges. */
8192 while (ebb->pred->src != ENTRY_BLOCK_PTR && ! ebb->pred->pred_next)
8194 ebb = ebb->pred->src;
8198 loop->pre_header_edges = (edge *) xmalloc (num * sizeof (edge *));
8199 loop->num_pre_header_edges = num;
8201 /* Store edges in order that they are followed. The source
8202 of the first edge is the root node of the pre-header extended
8203 basic block and the destination of the last last edge is
8205 for (e = loop->entry_edges[0]; num; e = e->src->pred)
8207 loop->pre_header_edges[--num] = e;
8213 /* Return the block for the pre-header of the loop with header
8214 HEADER where DOM specifies the dominator information. Return NULL if
8215 there is no pre-header. */
8218 flow_loop_pre_header_find (header, dom)
8222 basic_block pre_header;
8225 /* If block p is a predecessor of the header and is the only block
8226 that the header does not dominate, then it is the pre-header. */
8228 for (e = header->pred; e; e = e->pred_next)
8230 basic_block node = e->src;
8232 if (node != ENTRY_BLOCK_PTR
8233 && ! TEST_BIT (dom[node->index], header->index))
8235 if (pre_header == NULL)
8239 /* There are multiple edges into the header from outside
8240 the loop so there is no pre-header block. */
8249 /* Add LOOP to the loop hierarchy tree where PREVLOOP was the loop
8250 previously added. The insertion algorithm assumes that the loops
8251 are added in the order found by a depth first search of the CFG. */
8254 flow_loop_tree_node_add (prevloop, loop)
8255 struct loop *prevloop;
8259 if (flow_loop_nested_p (prevloop, loop))
8261 prevloop->inner = loop;
8262 loop->outer = prevloop;
8266 while (prevloop->outer)
8268 if (flow_loop_nested_p (prevloop->outer, loop))
8270 prevloop->next = loop;
8271 loop->outer = prevloop->outer;
8274 prevloop = prevloop->outer;
8277 prevloop->next = loop;
8281 /* Build the loop hierarchy tree for LOOPS. */
8284 flow_loops_tree_build (loops)
8285 struct loops *loops;
8290 num_loops = loops->num;
8294 /* Root the loop hierarchy tree with the first loop found.
8295 Since we used a depth first search this should be the
8297 loops->tree = &loops->array[0];
8298 loops->tree->outer = loops->tree->inner = loops->tree->next = NULL;
8300 /* Add the remaining loops to the tree. */
8301 for (i = 1; i < num_loops; i++)
8302 flow_loop_tree_node_add (&loops->array[i - 1], &loops->array[i]);
8305 /* Helper function to compute loop nesting depth and enclosed loop level
8306 for the natural loop specified by LOOP at the loop depth DEPTH.
8307 Returns the loop level. */
8310 flow_loop_level_compute (loop, depth)
8320 /* Traverse loop tree assigning depth and computing level as the
8321 maximum level of all the inner loops of this loop. The loop
8322 level is equivalent to the height of the loop in the loop tree
8323 and corresponds to the number of enclosed loop levels (including
8325 for (inner = loop->inner; inner; inner = inner->next)
8329 ilevel = flow_loop_level_compute (inner, depth + 1) + 1;
8334 loop->level = level;
8335 loop->depth = depth;
8339 /* Compute the loop nesting depth and enclosed loop level for the loop
8340 hierarchy tree specfied by LOOPS. Return the maximum enclosed loop
8344 flow_loops_level_compute (loops)
8345 struct loops *loops;
8351 /* Traverse all the outer level loops. */
8352 for (loop = loops->tree; loop; loop = loop->next)
8354 level = flow_loop_level_compute (loop, 1);
8362 /* Scan a single natural loop specified by LOOP collecting information
8363 about it specified by FLAGS. */
8366 flow_loop_scan (loops, loop, flags)
8367 struct loops *loops;
8371 /* Determine prerequisites. */
8372 if ((flags & LOOP_EXITS_DOMS) && ! loop->exit_edges)
8373 flags |= LOOP_EXIT_EDGES;
8375 if (flags & LOOP_ENTRY_EDGES)
8377 /* Find edges which enter the loop header.
8378 Note that the entry edges should only
8379 enter the header of a natural loop. */
8381 = flow_loop_entry_edges_find (loop->header,
8383 &loop->entry_edges);
8386 if (flags & LOOP_EXIT_EDGES)
8388 /* Find edges which exit the loop. */
8390 = flow_loop_exit_edges_find (loop->nodes,
8394 if (flags & LOOP_EXITS_DOMS)
8398 /* Determine which loop nodes dominate all the exits
8400 loop->exits_doms = sbitmap_alloc (n_basic_blocks);
8401 sbitmap_copy (loop->exits_doms, loop->nodes);
8402 for (j = 0; j < loop->num_exits; j++)
8403 sbitmap_a_and_b (loop->exits_doms, loop->exits_doms,
8404 loops->cfg.dom[loop->exit_edges[j]->src->index]);
8406 /* The header of a natural loop must dominate
8408 if (! TEST_BIT (loop->exits_doms, loop->header->index))
8412 if (flags & LOOP_PRE_HEADER)
8414 /* Look to see if the loop has a pre-header node. */
8416 = flow_loop_pre_header_find (loop->header, loops->cfg.dom);
8418 /* Find the blocks within the extended basic block of
8419 the loop pre-header. */
8420 flow_loop_pre_header_scan (loop);
8426 /* Find all the natural loops in the function and save in LOOPS structure
8427 and recalculate loop_depth information in basic block structures.
8428 FLAGS controls which loop information is collected.
8429 Return the number of natural loops found. */
8432 flow_loops_find (loops, flags)
8433 struct loops *loops;
8445 /* This function cannot be repeatedly called with different
8446 flags to build up the loop information. The loop tree
8447 must always be built if this function is called. */
8448 if (! (flags & LOOP_TREE))
8451 memset (loops, 0, sizeof (*loops));
8453 /* Taking care of this degenerate case makes the rest of
8454 this code simpler. */
8455 if (n_basic_blocks == 0)
8461 /* Compute the dominators. */
8462 dom = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
8463 calculate_dominance_info (NULL, dom, CDI_DOMINATORS);
8465 /* Count the number of loop edges (back edges). This should be the
8466 same as the number of natural loops. */
8469 for (b = 0; b < n_basic_blocks; b++)
8473 header = BASIC_BLOCK (b);
8474 header->loop_depth = 0;
8476 for (e = header->pred; e; e = e->pred_next)
8478 basic_block latch = e->src;
8480 /* Look for back edges where a predecessor is dominated
8481 by this block. A natural loop has a single entry
8482 node (header) that dominates all the nodes in the
8483 loop. It also has single back edge to the header
8484 from a latch node. Note that multiple natural loops
8485 may share the same header. */
8486 if (b != header->index)
8489 if (latch != ENTRY_BLOCK_PTR && TEST_BIT (dom[latch->index], b))
8496 /* Compute depth first search order of the CFG so that outer
8497 natural loops will be found before inner natural loops. */
8498 dfs_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
8499 rc_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
8500 flow_depth_first_order_compute (dfs_order, rc_order);
8502 /* Save CFG derived information to avoid recomputing it. */
8503 loops->cfg.dom = dom;
8504 loops->cfg.dfs_order = dfs_order;
8505 loops->cfg.rc_order = rc_order;
8507 /* Allocate loop structures. */
8509 = (struct loop *) xcalloc (num_loops, sizeof (struct loop));
8511 headers = sbitmap_alloc (n_basic_blocks);
8512 sbitmap_zero (headers);
8514 loops->shared_headers = sbitmap_alloc (n_basic_blocks);
8515 sbitmap_zero (loops->shared_headers);
8517 /* Find and record information about all the natural loops
8520 for (b = 0; b < n_basic_blocks; b++)
8524 /* Search the nodes of the CFG in reverse completion order
8525 so that we can find outer loops first. */
8526 header = BASIC_BLOCK (rc_order[b]);
8528 /* Look for all the possible latch blocks for this header. */
8529 for (e = header->pred; e; e = e->pred_next)
8531 basic_block latch = e->src;
8533 /* Look for back edges where a predecessor is dominated
8534 by this block. A natural loop has a single entry
8535 node (header) that dominates all the nodes in the
8536 loop. It also has single back edge to the header
8537 from a latch node. Note that multiple natural loops
8538 may share the same header. */
8539 if (latch != ENTRY_BLOCK_PTR
8540 && TEST_BIT (dom[latch->index], header->index))
8544 loop = loops->array + num_loops;
8546 loop->header = header;
8547 loop->latch = latch;
8548 loop->num = num_loops;
8555 for (i = 0; i < num_loops; i++)
8557 struct loop *loop = &loops->array[i];
8559 /* Keep track of blocks that are loop headers so
8560 that we can tell which loops should be merged. */
8561 if (TEST_BIT (headers, loop->header->index))
8562 SET_BIT (loops->shared_headers, loop->header->index);
8563 SET_BIT (headers, loop->header->index);
8565 /* Find nodes contained within the loop. */
8566 loop->nodes = sbitmap_alloc (n_basic_blocks);
8568 = flow_loop_nodes_find (loop->header, loop->latch, loop->nodes);
8570 /* Compute first and last blocks within the loop.
8571 These are often the same as the loop header and
8572 loop latch respectively, but this is not always
8575 = BASIC_BLOCK (sbitmap_first_set_bit (loop->nodes));
8577 = BASIC_BLOCK (sbitmap_last_set_bit (loop->nodes));
8579 flow_loop_scan (loops, loop, flags);
8582 /* Natural loops with shared headers may either be disjoint or
8583 nested. Disjoint loops with shared headers cannot be inner
8584 loops and should be merged. For now just mark loops that share
8586 for (i = 0; i < num_loops; i++)
8587 if (TEST_BIT (loops->shared_headers, loops->array[i].header->index))
8588 loops->array[i].shared = 1;
8590 sbitmap_free (headers);
8593 loops->num = num_loops;
8595 /* Build the loop hierarchy tree. */
8596 flow_loops_tree_build (loops);
8598 /* Assign the loop nesting depth and enclosed loop level for each
8600 loops->levels = flow_loops_level_compute (loops);
8606 /* Update the information regarding the loops in the CFG
8607 specified by LOOPS. */
8609 flow_loops_update (loops, flags)
8610 struct loops *loops;
8613 /* One day we may want to update the current loop data. For now
8614 throw away the old stuff and rebuild what we need. */
8616 flow_loops_free (loops);
8618 return flow_loops_find (loops, flags);
8622 /* Return non-zero if edge E enters header of LOOP from outside of LOOP. */
8625 flow_loop_outside_edge_p (loop, e)
8626 const struct loop *loop;
8629 if (e->dest != loop->header)
8631 return (e->src == ENTRY_BLOCK_PTR)
8632 || ! TEST_BIT (loop->nodes, e->src->index);
8635 /* Clear LOG_LINKS fields of insns in a chain.
8636 Also clear the global_live_at_{start,end} fields of the basic block
8640 clear_log_links (insns)
8646 for (i = insns; i; i = NEXT_INSN (i))
8650 for (b = 0; b < n_basic_blocks; b++)
8652 basic_block bb = BASIC_BLOCK (b);
8654 bb->global_live_at_start = NULL;
8655 bb->global_live_at_end = NULL;
8658 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
8659 EXIT_BLOCK_PTR->global_live_at_start = NULL;
8662 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
8663 correspond to the hard registers, if any, set in that map. This
8664 could be done far more efficiently by having all sorts of special-cases
8665 with moving single words, but probably isn't worth the trouble. */
8668 reg_set_to_hard_reg_set (to, from)
8674 EXECUTE_IF_SET_IN_BITMAP
8677 if (i >= FIRST_PSEUDO_REGISTER)
8679 SET_HARD_REG_BIT (*to, i);
8683 /* Called once at intialization time. */
8688 static int initialized;
8692 gcc_obstack_init (&flow_obstack);
8693 flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);
8698 obstack_free (&flow_obstack, flow_firstobj);
8699 flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);