1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
22 /* This file contains the data flow analysis pass of the compiler. It
23 computes data flow information which tells combine_instructions
24 which insns to consider combining and controls register allocation.
26 Additional data flow information that is too bulky to record is
27 generated during the analysis, and is used at that time to create
28 autoincrement and autodecrement addressing.
30 The first step is dividing the function into basic blocks.
31 find_basic_blocks does this. Then life_analysis determines
32 where each register is live and where it is dead.
34 ** find_basic_blocks **
36 find_basic_blocks divides the current function's rtl into basic
37 blocks and constructs the CFG. The blocks are recorded in the
38 basic_block_info array; the CFG exists in the edge structures
39 referenced by the blocks.
41 find_basic_blocks also finds any unreachable loops and deletes them.
45 life_analysis is called immediately after find_basic_blocks.
46 It uses the basic block information to determine where each
47 hard or pseudo register is live.
49 ** live-register info **
51 The information about where each register is live is in two parts:
52 the REG_NOTES of insns, and the vector basic_block->global_live_at_start.
54 basic_block->global_live_at_start has an element for each basic
55 block, and the element is a bit-vector with a bit for each hard or
56 pseudo register. The bit is 1 if the register is live at the
57 beginning of the basic block.
59 Two types of elements can be added to an insn's REG_NOTES.
60 A REG_DEAD note is added to an insn's REG_NOTES for any register
61 that meets both of two conditions: The value in the register is not
62 needed in subsequent insns and the insn does not replace the value in
63 the register (in the case of multi-word hard registers, the value in
64 each register must be replaced by the insn to avoid a REG_DEAD note).
66 In the vast majority of cases, an object in a REG_DEAD note will be
67 used somewhere in the insn. The (rare) exception to this is if an
68 insn uses a multi-word hard register and only some of the registers are
69 needed in subsequent insns. In that case, REG_DEAD notes will be
70 provided for those hard registers that are not subsequently needed.
71 Partial REG_DEAD notes of this type do not occur when an insn sets
72 only some of the hard registers used in such a multi-word operand;
73 omitting REG_DEAD notes for objects stored in an insn is optional and
74 the desire to do so does not justify the complexity of the partial
77 REG_UNUSED notes are added for each register that is set by the insn
78 but is unused subsequently (if every register set by the insn is unused
79 and the insn does not reference memory or have some other side-effect,
80 the insn is deleted instead). If only part of a multi-word hard
81 register is used in a subsequent insn, REG_UNUSED notes are made for
82 the parts that will not be used.
84 To determine which registers are live after any insn, one can
85 start from the beginning of the basic block and scan insns, noting
86 which registers are set by each insn and which die there.
88 ** Other actions of life_analysis **
90 life_analysis sets up the LOG_LINKS fields of insns because the
91 information needed to do so is readily available.
93 life_analysis deletes insns whose only effect is to store a value
96 life_analysis notices cases where a reference to a register as
97 a memory address can be combined with a preceding or following
98 incrementation or decrementation of the register. The separate
99 instruction to increment or decrement is deleted and the address
100 is changed to a POST_INC or similar rtx.
102 Each time an incrementing or decrementing address is created,
103 a REG_INC element is added to the insn's REG_NOTES list.
105 life_analysis fills in certain vectors containing information about
106 register usage: REG_N_REFS, REG_N_DEATHS, REG_N_SETS, REG_LIVE_LENGTH,
107 REG_N_CALLS_CROSSED and REG_BASIC_BLOCK.
109 life_analysis sets current_function_sp_is_unchanging if the function
110 doesn't modify the stack pointer. */
114 Split out from life_analysis:
115 - local property discovery (bb->local_live, bb->local_set)
116 - global property computation
118 - pre/post modify transformation
126 #include "hard-reg-set.h"
127 #include "basic-block.h"
128 #include "insn-config.h"
132 #include "function.h"
140 #include "splay-tree.h"
142 #define obstack_chunk_alloc xmalloc
143 #define obstack_chunk_free free
145 /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
146 the stack pointer does not matter. The value is tested only in
147 functions that have frame pointers.
148 No definition is equivalent to always zero. */
149 #ifndef EXIT_IGNORE_STACK
150 #define EXIT_IGNORE_STACK 0
153 #ifndef HAVE_epilogue
154 #define HAVE_epilogue 0
156 #ifndef HAVE_prologue
157 #define HAVE_prologue 0
159 #ifndef HAVE_sibcall_epilogue
160 #define HAVE_sibcall_epilogue 0
164 #define LOCAL_REGNO(REGNO) 0
166 #ifndef EPILOGUE_USES
167 #define EPILOGUE_USES(REGNO) 0
170 #ifdef HAVE_conditional_execution
171 #ifndef REVERSE_CONDEXEC_PREDICATES_P
172 #define REVERSE_CONDEXEC_PREDICATES_P(x, y) ((x) == reverse_condition (y))
176 /* The obstack on which the flow graph components are allocated. */
178 struct obstack flow_obstack;
179 static char *flow_firstobj;
181 /* Number of basic blocks in the current function. */
185 /* Number of edges in the current function. */
189 /* The basic block array. */
191 varray_type basic_block_info;
193 /* The special entry and exit blocks. */
195 struct basic_block_def entry_exit_blocks[2]
198 NULL, /* head_tree */
202 NULL, /* local_set */
203 NULL, /* cond_local_set */
204 NULL, /* global_live_at_start */
205 NULL, /* global_live_at_end */
207 ENTRY_BLOCK, /* index */
215 NULL, /* head_tree */
219 NULL, /* local_set */
220 NULL, /* cond_local_set */
221 NULL, /* global_live_at_start */
222 NULL, /* global_live_at_end */
224 EXIT_BLOCK, /* index */
231 /* Nonzero if the second flow pass has completed. */
234 /* Maximum register number used in this function, plus one. */
238 /* Indexed by n, giving various register information */
240 varray_type reg_n_info;
242 /* Size of a regset for the current function,
243 in (1) bytes and (2) elements. */
248 /* Regset of regs live when calls to `setjmp'-like functions happen. */
249 /* ??? Does this exist only for the setjmp-clobbered warning message? */
251 regset regs_live_at_setjmp;
253 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
254 that have to go in the same hard reg.
255 The first two regs in the list are a pair, and the next two
256 are another pair, etc. */
259 /* Callback that determines if it's ok for a function to have no
260 noreturn attribute. */
261 int (*lang_missing_noreturn_ok_p) PARAMS ((tree));
263 /* Set of registers that may be eliminable. These are handled specially
264 in updating regs_ever_live. */
266 static HARD_REG_SET elim_reg_set;
268 /* The basic block structure for every insn, indexed by uid. */
270 varray_type basic_block_for_insn;
272 /* The labels mentioned in non-jump rtl. Valid during find_basic_blocks. */
273 /* ??? Should probably be using LABEL_NUSES instead. It would take a
274 bit of surgery to be able to use or co-opt the routines in jump. */
276 static rtx label_value_list;
277 static rtx tail_recursion_label_list;
279 /* Holds information for tracking conditional register life information. */
280 struct reg_cond_life_info
282 /* A boolean expression of conditions under which a register is dead. */
284 /* Conditions under which a register is dead at the basic block end. */
287 /* A boolean expression of conditions under which a register has been
291 /* ??? Could store mask of bytes that are dead, so that we could finally
292 track lifetimes of multi-word registers accessed via subregs. */
295 /* For use in communicating between propagate_block and its subroutines.
296 Holds all information needed to compute life and def-use information. */
298 struct propagate_block_info
300 /* The basic block we're considering. */
303 /* Bit N is set if register N is conditionally or unconditionally live. */
306 /* Bit N is set if register N is set this insn. */
309 /* Element N is the next insn that uses (hard or pseudo) register N
310 within the current basic block; or zero, if there is no such insn. */
313 /* Contains a list of all the MEMs we are tracking for dead store
317 /* If non-null, record the set of registers set unconditionally in the
321 /* If non-null, record the set of registers set conditionally in the
323 regset cond_local_set;
325 #ifdef HAVE_conditional_execution
326 /* Indexed by register number, holds a reg_cond_life_info for each
327 register that is not unconditionally live or dead. */
328 splay_tree reg_cond_dead;
330 /* Bit N is set if register N is in an expression in reg_cond_dead. */
334 /* The length of mem_set_list. */
335 int mem_set_list_len;
337 /* Non-zero if the value of CC0 is live. */
340 /* Flags controling the set of information propagate_block collects. */
344 /* Maximum length of pbi->mem_set_list before we start dropping
345 new elements on the floor. */
346 #define MAX_MEM_SET_LIST_LEN 100
348 /* Store the data structures necessary for depth-first search. */
349 struct depth_first_search_dsS {
350 /* stack for backtracking during the algorithm */
353 /* number of edges in the stack. That is, positions 0, ..., sp-1
357 /* record of basic blocks already seen by depth-first search */
358 sbitmap visited_blocks;
360 typedef struct depth_first_search_dsS *depth_first_search_ds;
362 /* Have print_rtl_and_abort give the same information that fancy_abort
364 #define print_rtl_and_abort() \
365 print_rtl_and_abort_fcn (__FILE__, __LINE__, __FUNCTION__)
367 /* Forward declarations */
368 static bool try_crossjump_to_edge PARAMS ((int, edge, edge));
369 static bool try_crossjump_bb PARAMS ((int, basic_block));
370 static bool outgoing_edges_match PARAMS ((basic_block, basic_block));
371 static int flow_find_cross_jump PARAMS ((int, basic_block, basic_block,
373 static int count_basic_blocks PARAMS ((rtx));
374 static void find_basic_blocks_1 PARAMS ((rtx));
375 static rtx find_label_refs PARAMS ((rtx, rtx));
376 static void make_edges PARAMS ((rtx));
377 static void make_label_edge PARAMS ((sbitmap *, basic_block,
379 static void make_eh_edge PARAMS ((sbitmap *, basic_block, rtx));
381 static void commit_one_edge_insertion PARAMS ((edge));
383 static void delete_unreachable_blocks PARAMS ((void));
384 static int can_delete_note_p PARAMS ((rtx));
385 static void expunge_block PARAMS ((basic_block));
386 static int can_delete_label_p PARAMS ((rtx));
387 static int tail_recursion_label_p PARAMS ((rtx));
388 static int merge_blocks_move_predecessor_nojumps PARAMS ((basic_block,
390 static int merge_blocks_move_successor_nojumps PARAMS ((basic_block,
392 static int merge_blocks PARAMS ((edge,basic_block,basic_block,
394 static bool try_optimize_cfg PARAMS ((int));
395 static bool forwarder_block_p PARAMS ((basic_block));
396 static bool can_fallthru PARAMS ((basic_block, basic_block));
397 static bool try_redirect_by_replacing_jump PARAMS ((edge, basic_block));
398 static bool try_simplify_condjump PARAMS ((basic_block));
399 static bool try_forward_edges PARAMS ((basic_block));
400 static void tidy_fallthru_edges PARAMS ((void));
401 static int verify_wide_reg_1 PARAMS ((rtx *, void *));
402 static void verify_wide_reg PARAMS ((int, rtx, rtx));
403 static void verify_local_live_at_start PARAMS ((regset, basic_block));
404 static int noop_move_p PARAMS ((rtx));
405 static void delete_noop_moves PARAMS ((rtx));
406 static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
407 static void notice_stack_pointer_modification PARAMS ((rtx));
408 static void mark_reg PARAMS ((rtx, void *));
409 static void mark_regs_live_at_end PARAMS ((regset));
410 static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
411 static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
412 static void propagate_block_delete_insn PARAMS ((basic_block, rtx));
413 static rtx propagate_block_delete_libcall PARAMS ((basic_block, rtx, rtx));
414 static int insn_dead_p PARAMS ((struct propagate_block_info *,
416 static int libcall_dead_p PARAMS ((struct propagate_block_info *,
418 static void mark_set_regs PARAMS ((struct propagate_block_info *,
420 static void mark_set_1 PARAMS ((struct propagate_block_info *,
421 enum rtx_code, rtx, rtx,
423 #ifdef HAVE_conditional_execution
424 static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
426 static void free_reg_cond_life_info PARAMS ((splay_tree_value));
427 static int flush_reg_cond_reg_1 PARAMS ((splay_tree_node, void *));
428 static void flush_reg_cond_reg PARAMS ((struct propagate_block_info *,
430 static rtx elim_reg_cond PARAMS ((rtx, unsigned int));
431 static rtx ior_reg_cond PARAMS ((rtx, rtx, int));
432 static rtx not_reg_cond PARAMS ((rtx));
433 static rtx and_reg_cond PARAMS ((rtx, rtx, int));
436 static void attempt_auto_inc PARAMS ((struct propagate_block_info *,
437 rtx, rtx, rtx, rtx, rtx));
438 static void find_auto_inc PARAMS ((struct propagate_block_info *,
440 static int try_pre_increment_1 PARAMS ((struct propagate_block_info *,
442 static int try_pre_increment PARAMS ((rtx, rtx, HOST_WIDE_INT));
444 static void mark_used_reg PARAMS ((struct propagate_block_info *,
446 static void mark_used_regs PARAMS ((struct propagate_block_info *,
448 void dump_flow_info PARAMS ((FILE *));
449 void debug_flow_info PARAMS ((void));
450 static void print_rtl_and_abort_fcn PARAMS ((const char *, int,
454 static void invalidate_mems_from_autoinc PARAMS ((struct propagate_block_info *,
456 static void invalidate_mems_from_set PARAMS ((struct propagate_block_info *,
458 static void remove_fake_successors PARAMS ((basic_block));
459 static void flow_nodes_print PARAMS ((const char *, const sbitmap,
461 static void flow_edge_list_print PARAMS ((const char *, const edge *,
463 static void flow_loops_cfg_dump PARAMS ((const struct loops *,
465 static int flow_loop_nested_p PARAMS ((struct loop *,
467 static int flow_loop_entry_edges_find PARAMS ((basic_block, const sbitmap,
469 static int flow_loop_exit_edges_find PARAMS ((const sbitmap, edge **));
470 static int flow_loop_nodes_find PARAMS ((basic_block, basic_block, sbitmap));
471 static void flow_dfs_compute_reverse_init
472 PARAMS ((depth_first_search_ds));
473 static void flow_dfs_compute_reverse_add_bb
474 PARAMS ((depth_first_search_ds, basic_block));
475 static basic_block flow_dfs_compute_reverse_execute
476 PARAMS ((depth_first_search_ds));
477 static void flow_dfs_compute_reverse_finish
478 PARAMS ((depth_first_search_ds));
479 static void flow_loop_pre_header_scan PARAMS ((struct loop *));
480 static basic_block flow_loop_pre_header_find PARAMS ((basic_block,
482 static void flow_loop_tree_node_add PARAMS ((struct loop *, struct loop *));
483 static void flow_loops_tree_build PARAMS ((struct loops *));
484 static int flow_loop_level_compute PARAMS ((struct loop *, int));
485 static int flow_loops_level_compute PARAMS ((struct loops *));
486 static void allocate_bb_life_data PARAMS ((void));
487 static void find_sub_basic_blocks PARAMS ((basic_block));
488 static bool redirect_edge_and_branch PARAMS ((edge, basic_block));
489 static basic_block redirect_edge_and_branch_force PARAMS ((edge, basic_block));
490 static rtx block_label PARAMS ((basic_block));
492 /* Find basic blocks of the current function.
493 F is the first insn of the function and NREGS the number of register
497 find_basic_blocks (f, nregs, file)
499 int nregs ATTRIBUTE_UNUSED;
500 FILE *file ATTRIBUTE_UNUSED;
504 /* Flush out existing data. */
505 if (basic_block_info != NULL)
511 /* Clear bb->aux on all extant basic blocks. We'll use this as a
512 tag for reuse during create_basic_block, just in case some pass
513 copies around basic block notes improperly. */
514 for (i = 0; i < n_basic_blocks; ++i)
515 BASIC_BLOCK (i)->aux = NULL;
517 VARRAY_FREE (basic_block_info);
520 n_basic_blocks = count_basic_blocks (f);
522 /* Size the basic block table. The actual structures will be allocated
523 by find_basic_blocks_1, since we want to keep the structure pointers
524 stable across calls to find_basic_blocks. */
525 /* ??? This whole issue would be much simpler if we called find_basic_blocks
526 exactly once, and thereafter we don't have a single long chain of
527 instructions at all until close to the end of compilation when we
528 actually lay them out. */
530 VARRAY_BB_INIT (basic_block_info, n_basic_blocks, "basic_block_info");
532 find_basic_blocks_1 (f);
534 /* Record the block to which an insn belongs. */
535 /* ??? This should be done another way, by which (perhaps) a label is
536 tagged directly with the basic block that it starts. It is used for
537 more than that currently, but IMO that is the only valid use. */
539 max_uid = get_max_uid ();
541 /* Leave space for insns life_analysis makes in some cases for auto-inc.
542 These cases are rare, so we don't need too much space. */
543 max_uid += max_uid / 10;
546 compute_bb_for_insn (max_uid);
548 /* Discover the edges of our cfg. */
549 make_edges (label_value_list);
551 /* Do very simple cleanup now, for the benefit of code that runs between
552 here and cleanup_cfg, e.g. thread_prologue_and_epilogue_insns. */
553 tidy_fallthru_edges ();
555 mark_critical_edges ();
557 #ifdef ENABLE_CHECKING
563 check_function_return_warnings ()
565 if (warn_missing_noreturn
566 && !TREE_THIS_VOLATILE (cfun->decl)
567 && EXIT_BLOCK_PTR->pred == NULL
568 && (lang_missing_noreturn_ok_p
569 && !lang_missing_noreturn_ok_p (cfun->decl)))
570 warning ("function might be possible candidate for attribute `noreturn'");
572 /* If we have a path to EXIT, then we do return. */
573 if (TREE_THIS_VOLATILE (cfun->decl)
574 && EXIT_BLOCK_PTR->pred != NULL)
575 warning ("`noreturn' function does return");
577 /* If the clobber_return_insn appears in some basic block, then we
578 do reach the end without returning a value. */
579 else if (warn_return_type
580 && cfun->x_clobber_return_insn != NULL
581 && EXIT_BLOCK_PTR->pred != NULL)
583 int max_uid = get_max_uid ();
585 /* If clobber_return_insn was excised by jump1, then renumber_insns
586 can make max_uid smaller than the number still recorded in our rtx.
587 That's fine, since this is a quick way of verifying that the insn
588 is no longer in the chain. */
589 if (INSN_UID (cfun->x_clobber_return_insn) < max_uid)
591 /* Recompute insn->block mapping, since the initial mapping is
592 set before we delete unreachable blocks. */
593 compute_bb_for_insn (max_uid);
595 if (BLOCK_FOR_INSN (cfun->x_clobber_return_insn) != NULL)
596 warning ("control reaches end of non-void function");
601 /* Count the basic blocks of the function. */
604 count_basic_blocks (f)
608 register RTX_CODE prev_code;
609 register int count = 0;
610 int saw_abnormal_edge = 0;
612 prev_code = JUMP_INSN;
613 for (insn = f; insn; insn = NEXT_INSN (insn))
615 enum rtx_code code = GET_CODE (insn);
617 if (code == CODE_LABEL
618 || (GET_RTX_CLASS (code) == 'i'
619 && (prev_code == JUMP_INSN
620 || prev_code == BARRIER
621 || saw_abnormal_edge)))
623 saw_abnormal_edge = 0;
627 /* Record whether this insn created an edge. */
628 if (code == CALL_INSN)
632 /* If there is a nonlocal goto label and the specified
633 region number isn't -1, we have an edge. */
634 if (nonlocal_goto_handler_labels
635 && ((note = find_reg_note (insn, REG_EH_REGION, NULL_RTX)) == 0
636 || INTVAL (XEXP (note, 0)) >= 0))
637 saw_abnormal_edge = 1;
639 else if (can_throw_internal (insn))
640 saw_abnormal_edge = 1;
642 else if (flag_non_call_exceptions
644 && can_throw_internal (insn))
645 saw_abnormal_edge = 1;
651 /* The rest of the compiler works a bit smoother when we don't have to
652 check for the edge case of do-nothing functions with no basic blocks. */
655 emit_insn (gen_rtx_USE (VOIDmode, const0_rtx));
662 /* Scan a list of insns for labels referred to other than by jumps.
663 This is used to scan the alternatives of a call placeholder. */
665 find_label_refs (f, lvl)
671 for (insn = f; insn; insn = NEXT_INSN (insn))
672 if (INSN_P (insn) && GET_CODE (insn) != JUMP_INSN)
676 /* Make a list of all labels referred to other than by jumps
677 (which just don't have the REG_LABEL notes).
679 Make a special exception for labels followed by an ADDR*VEC,
680 as this would be a part of the tablejump setup code.
682 Make a special exception to registers loaded with label
683 values just before jump insns that use them. */
685 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
686 if (REG_NOTE_KIND (note) == REG_LABEL)
688 rtx lab = XEXP (note, 0), next;
690 if ((next = next_nonnote_insn (lab)) != NULL
691 && GET_CODE (next) == JUMP_INSN
692 && (GET_CODE (PATTERN (next)) == ADDR_VEC
693 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
695 else if (GET_CODE (lab) == NOTE)
697 else if (GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
698 && find_reg_note (NEXT_INSN (insn), REG_LABEL, lab))
701 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
708 /* Assume that someone emitted code with control flow instructions to the
709 basic block. Update the data structure. */
711 find_sub_basic_blocks (bb)
714 rtx first_insn = bb->head, insn;
716 edge succ_list = bb->succ;
717 rtx jump_insn = NULL_RTX;
721 basic_block first_bb = bb, last_bb;
724 if (GET_CODE (first_insn) == LABEL_REF)
725 first_insn = NEXT_INSN (first_insn);
726 first_insn = NEXT_INSN (first_insn);
730 /* Scan insn chain and try to find new basic block boundaries. */
733 enum rtx_code code = GET_CODE (insn);
737 /* We need some special care for those expressions. */
738 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
739 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
748 /* On code label, split current basic block. */
750 falltru = split_block (bb, PREV_INSN (insn));
755 remove_edge (falltru);
759 if (LABEL_ALTERNATE_NAME (insn))
760 make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0);
763 /* In case we've previously split insn on the JUMP_INSN, move the
764 block header to proper place. */
767 falltru = split_block (bb, PREV_INSN (insn));
777 insn = NEXT_INSN (insn);
779 /* Last basic block must end in the original BB end. */
783 /* Wire in the original edges for last basic block. */
786 bb->succ = succ_list;
788 succ_list->src = bb, succ_list = succ_list->succ_next;
791 bb->succ = succ_list;
793 /* Now re-scan and wire in all edges. This expect simple (conditional)
794 jumps at the end of each new basic blocks. */
796 for (i = first_bb->index; i < last_bb->index; i++)
798 bb = BASIC_BLOCK (i);
799 if (GET_CODE (bb->end) == JUMP_INSN)
801 mark_jump_label (PATTERN (bb->end), bb->end, 0, 0);
802 make_label_edge (NULL, bb, JUMP_LABEL (bb->end), 0);
804 insn = NEXT_INSN (insn);
808 /* Find all basic blocks of the function whose first insn is F.
810 Collect and return a list of labels whose addresses are taken. This
811 will be used in make_edges for use with computed gotos. */
814 find_basic_blocks_1 (f)
817 register rtx insn, next;
819 rtx bb_note = NULL_RTX;
825 /* We process the instructions in a slightly different way than we did
826 previously. This is so that we see a NOTE_BASIC_BLOCK after we have
827 closed out the previous block, so that it gets attached at the proper
828 place. Since this form should be equivalent to the previous,
829 count_basic_blocks continues to use the old form as a check. */
831 for (insn = f; insn; insn = next)
833 enum rtx_code code = GET_CODE (insn);
835 next = NEXT_INSN (insn);
841 int kind = NOTE_LINE_NUMBER (insn);
843 /* Look for basic block notes with which to keep the
844 basic_block_info pointers stable. Unthread the note now;
845 we'll put it back at the right place in create_basic_block.
846 Or not at all if we've already found a note in this block. */
847 if (kind == NOTE_INSN_BASIC_BLOCK)
849 if (bb_note == NULL_RTX)
852 next = flow_delete_insn (insn);
858 /* A basic block starts at a label. If we've closed one off due
859 to a barrier or some such, no need to do it again. */
860 if (head != NULL_RTX)
862 /* While we now have edge lists with which other portions of
863 the compiler might determine a call ending a basic block
864 does not imply an abnormal edge, it will be a bit before
865 everything can be updated. So continue to emit a noop at
866 the end of such a block. */
867 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
869 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
870 end = emit_insn_after (nop, end);
873 create_basic_block (i++, head, end, bb_note);
881 /* A basic block ends at a jump. */
882 if (head == NULL_RTX)
886 /* ??? Make a special check for table jumps. The way this
887 happens is truly and amazingly gross. We are about to
888 create a basic block that contains just a code label and
889 an addr*vec jump insn. Worse, an addr_diff_vec creates
890 its own natural loop.
892 Prevent this bit of brain damage, pasting things together
893 correctly in make_edges.
895 The correct solution involves emitting the table directly
896 on the tablejump instruction as a note, or JUMP_LABEL. */
898 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
899 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
907 goto new_bb_inclusive;
910 /* A basic block ends at a barrier. It may be that an unconditional
911 jump already closed the basic block -- no need to do it again. */
912 if (head == NULL_RTX)
915 /* While we now have edge lists with which other portions of the
916 compiler might determine a call ending a basic block does not
917 imply an abnormal edge, it will be a bit before everything can
918 be updated. So continue to emit a noop at the end of such a
920 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
922 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
923 end = emit_insn_after (nop, end);
925 goto new_bb_exclusive;
929 /* Record whether this call created an edge. */
930 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
931 int region = (note ? INTVAL (XEXP (note, 0)) : 0);
933 if (GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
935 /* Scan each of the alternatives for label refs. */
936 lvl = find_label_refs (XEXP (PATTERN (insn), 0), lvl);
937 lvl = find_label_refs (XEXP (PATTERN (insn), 1), lvl);
938 lvl = find_label_refs (XEXP (PATTERN (insn), 2), lvl);
939 /* Record its tail recursion label, if any. */
940 if (XEXP (PATTERN (insn), 3) != NULL_RTX)
941 trll = alloc_EXPR_LIST (0, XEXP (PATTERN (insn), 3), trll);
944 /* A basic block ends at a call that can either throw or
945 do a non-local goto. */
946 if ((nonlocal_goto_handler_labels && region >= 0)
947 || can_throw_internal (insn))
950 if (head == NULL_RTX)
955 create_basic_block (i++, head, end, bb_note);
956 head = end = NULL_RTX;
964 /* Non-call exceptions generate new blocks just like calls. */
965 if (flag_non_call_exceptions && can_throw_internal (insn))
966 goto new_bb_inclusive;
968 if (head == NULL_RTX)
977 if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
981 /* Make a list of all labels referred to other than by jumps.
983 Make a special exception for labels followed by an ADDR*VEC,
984 as this would be a part of the tablejump setup code.
986 Make a special exception to registers loaded with label
987 values just before jump insns that use them. */
989 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
990 if (REG_NOTE_KIND (note) == REG_LABEL)
992 rtx lab = XEXP (note, 0), next;
994 if ((next = next_nonnote_insn (lab)) != NULL
995 && GET_CODE (next) == JUMP_INSN
996 && (GET_CODE (PATTERN (next)) == ADDR_VEC
997 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
999 else if (GET_CODE (lab) == NOTE)
1001 else if (GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
1002 && find_reg_note (NEXT_INSN (insn), REG_LABEL, lab))
1005 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
1010 if (head != NULL_RTX)
1011 create_basic_block (i++, head, end, bb_note);
1013 flow_delete_insn (bb_note);
1015 if (i != n_basic_blocks)
1018 label_value_list = lvl;
1019 tail_recursion_label_list = trll;
1022 /* Tidy the CFG by deleting unreachable code and whatnot. */
1028 delete_unreachable_blocks ();
1029 if (try_optimize_cfg (mode))
1030 delete_unreachable_blocks ();
1031 mark_critical_edges ();
1033 /* Kill the data we won't maintain. */
1034 free_EXPR_LIST_list (&label_value_list);
1035 free_EXPR_LIST_list (&tail_recursion_label_list);
1038 /* Create a new basic block consisting of the instructions between
1039 HEAD and END inclusive. Reuses the note and basic block struct
1040 in BB_NOTE, if any. */
1043 create_basic_block (index, head, end, bb_note)
1045 rtx head, end, bb_note;
1050 && ! RTX_INTEGRATED_P (bb_note)
1051 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
1054 /* If we found an existing note, thread it back onto the chain. */
1058 if (GET_CODE (head) == CODE_LABEL)
1062 after = PREV_INSN (head);
1066 if (after != bb_note && NEXT_INSN (after) != bb_note)
1067 reorder_insns (bb_note, bb_note, after);
1071 /* Otherwise we must create a note and a basic block structure.
1072 Since we allow basic block structs in rtl, give the struct
1073 the same lifetime by allocating it off the function obstack
1074 rather than using malloc. */
1076 bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*bb));
1077 memset (bb, 0, sizeof (*bb));
1079 if (GET_CODE (head) == CODE_LABEL)
1080 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
1083 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
1086 NOTE_BASIC_BLOCK (bb_note) = bb;
1089 /* Always include the bb note in the block. */
1090 if (NEXT_INSN (end) == bb_note)
1096 BASIC_BLOCK (index) = bb;
1098 /* Tag the block so that we know it has been used when considering
1099 other basic block notes. */
1103 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
1104 note associated with the BLOCK. */
1107 first_insn_after_basic_block_note (block)
1112 /* Get the first instruction in the block. */
1115 if (insn == NULL_RTX)
1117 if (GET_CODE (insn) == CODE_LABEL)
1118 insn = NEXT_INSN (insn);
1119 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
1122 return NEXT_INSN (insn);
1125 /* Records the basic block struct in BB_FOR_INSN, for every instruction
1126 indexed by INSN_UID. MAX is the size of the array. */
1129 compute_bb_for_insn (max)
1134 if (basic_block_for_insn)
1135 VARRAY_FREE (basic_block_for_insn);
1136 VARRAY_BB_INIT (basic_block_for_insn, max, "basic_block_for_insn");
1138 for (i = 0; i < n_basic_blocks; ++i)
1140 basic_block bb = BASIC_BLOCK (i);
1147 int uid = INSN_UID (insn);
1149 VARRAY_BB (basic_block_for_insn, uid) = bb;
1152 insn = NEXT_INSN (insn);
1157 /* Free the memory associated with the edge structures. */
1165 for (i = 0; i < n_basic_blocks; ++i)
1167 basic_block bb = BASIC_BLOCK (i);
1169 for (e = bb->succ; e; e = n)
1179 for (e = ENTRY_BLOCK_PTR->succ; e; e = n)
1185 ENTRY_BLOCK_PTR->succ = 0;
1186 EXIT_BLOCK_PTR->pred = 0;
1191 /* Identify the edges between basic blocks.
1193 NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks
1194 that are otherwise unreachable may be reachable with a non-local goto.
1196 BB_EH_END is an array indexed by basic block number in which we record
1197 the list of exception regions active at the end of the basic block. */
1200 make_edges (label_value_list)
1201 rtx label_value_list;
1204 sbitmap *edge_cache = NULL;
1206 /* Assume no computed jump; revise as we create edges. */
1207 current_function_has_computed_jump = 0;
1209 /* Heavy use of computed goto in machine-generated code can lead to
1210 nearly fully-connected CFGs. In that case we spend a significant
1211 amount of time searching the edge lists for duplicates. */
1212 if (forced_labels || label_value_list)
1214 edge_cache = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
1215 sbitmap_vector_zero (edge_cache, n_basic_blocks);
1218 /* By nature of the way these get numbered, block 0 is always the entry. */
1219 make_edge (edge_cache, ENTRY_BLOCK_PTR, BASIC_BLOCK (0), EDGE_FALLTHRU);
1221 for (i = 0; i < n_basic_blocks; ++i)
1223 basic_block bb = BASIC_BLOCK (i);
1226 int force_fallthru = 0;
1228 if (GET_CODE (bb->head) == CODE_LABEL
1229 && LABEL_ALTERNATE_NAME (bb->head))
1230 make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0);
1232 /* Examine the last instruction of the block, and discover the
1233 ways we can leave the block. */
1236 code = GET_CODE (insn);
1239 if (code == JUMP_INSN)
1243 /* Recognize exception handling placeholders. */
1244 if (GET_CODE (PATTERN (insn)) == RESX)
1245 make_eh_edge (edge_cache, bb, insn);
1247 /* Recognize a non-local goto as a branch outside the
1248 current function. */
1249 else if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX))
1252 /* ??? Recognize a tablejump and do the right thing. */
1253 else if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1254 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1255 && GET_CODE (tmp) == JUMP_INSN
1256 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1257 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1262 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1263 vec = XVEC (PATTERN (tmp), 0);
1265 vec = XVEC (PATTERN (tmp), 1);
1267 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1268 make_label_edge (edge_cache, bb,
1269 XEXP (RTVEC_ELT (vec, j), 0), 0);
1271 /* Some targets (eg, ARM) emit a conditional jump that also
1272 contains the out-of-range target. Scan for these and
1273 add an edge if necessary. */
1274 if ((tmp = single_set (insn)) != NULL
1275 && SET_DEST (tmp) == pc_rtx
1276 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1277 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF)
1278 make_label_edge (edge_cache, bb,
1279 XEXP (XEXP (SET_SRC (tmp), 2), 0), 0);
1281 #ifdef CASE_DROPS_THROUGH
1282 /* Silly VAXen. The ADDR_VEC is going to be in the way of
1283 us naturally detecting fallthru into the next block. */
1288 /* If this is a computed jump, then mark it as reaching
1289 everything on the label_value_list and forced_labels list. */
1290 else if (computed_jump_p (insn))
1292 current_function_has_computed_jump = 1;
1294 for (x = label_value_list; x; x = XEXP (x, 1))
1295 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1297 for (x = forced_labels; x; x = XEXP (x, 1))
1298 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1301 /* Returns create an exit out. */
1302 else if (returnjump_p (insn))
1303 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, 0);
1305 /* Otherwise, we have a plain conditional or unconditional jump. */
1308 if (! JUMP_LABEL (insn))
1310 make_label_edge (edge_cache, bb, JUMP_LABEL (insn), 0);
1314 /* If this is a sibling call insn, then this is in effect a
1315 combined call and return, and so we need an edge to the
1316 exit block. No need to worry about EH edges, since we
1317 wouldn't have created the sibling call in the first place. */
1319 if (code == CALL_INSN && SIBLING_CALL_P (insn))
1320 make_edge (edge_cache, bb, EXIT_BLOCK_PTR,
1321 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1323 /* If this is a CALL_INSN, then mark it as reaching the active EH
1324 handler for this CALL_INSN. If we're handling non-call
1325 exceptions then any insn can reach any of the active handlers.
1327 Also mark the CALL_INSN as reaching any nonlocal goto handler. */
1329 else if (code == CALL_INSN || flag_non_call_exceptions)
1331 /* Add any appropriate EH edges. */
1332 make_eh_edge (edge_cache, bb, insn);
1334 if (code == CALL_INSN && nonlocal_goto_handler_labels)
1336 /* ??? This could be made smarter: in some cases it's possible
1337 to tell that certain calls will not do a nonlocal goto.
1339 For example, if the nested functions that do the nonlocal
1340 gotos do not have their addresses taken, then only calls to
1341 those functions or to other nested functions that use them
1342 could possibly do nonlocal gotos. */
1343 /* We do know that a REG_EH_REGION note with a value less
1344 than 0 is guaranteed not to perform a non-local goto. */
1345 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
1346 if (!note || INTVAL (XEXP (note, 0)) >= 0)
1347 for (x = nonlocal_goto_handler_labels; x; x = XEXP (x, 1))
1348 make_label_edge (edge_cache, bb, XEXP (x, 0),
1349 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1353 /* Find out if we can drop through to the next block. */
1354 insn = next_nonnote_insn (insn);
1355 if (!insn || (i + 1 == n_basic_blocks && force_fallthru))
1356 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU);
1357 else if (i + 1 < n_basic_blocks)
1359 rtx tmp = BLOCK_HEAD (i + 1);
1360 if (GET_CODE (tmp) == NOTE)
1361 tmp = next_nonnote_insn (tmp);
1362 if (force_fallthru || insn == tmp)
1363 make_edge (edge_cache, bb, BASIC_BLOCK (i + 1), EDGE_FALLTHRU);
1368 sbitmap_vector_free (edge_cache);
1371 /* Create an edge between two basic blocks. FLAGS are auxiliary information
1372 about the edge that is accumulated between calls. */
1375 make_edge (edge_cache, src, dst, flags)
1376 sbitmap *edge_cache;
1377 basic_block src, dst;
1383 /* Don't bother with edge cache for ENTRY or EXIT; there aren't that
1384 many edges to them, and we didn't allocate memory for it. */
1385 use_edge_cache = (edge_cache
1386 && src != ENTRY_BLOCK_PTR
1387 && dst != EXIT_BLOCK_PTR);
1389 /* Make sure we don't add duplicate edges. */
1390 switch (use_edge_cache)
1393 /* Quick test for non-existance of the edge. */
1394 if (! TEST_BIT (edge_cache[src->index], dst->index))
1397 /* The edge exists; early exit if no work to do. */
1403 for (e = src->succ; e; e = e->succ_next)
1412 e = (edge) xcalloc (1, sizeof (*e));
1415 e->succ_next = src->succ;
1416 e->pred_next = dst->pred;
1425 SET_BIT (edge_cache[src->index], dst->index);
1428 /* Create an edge from a basic block to a label. */
1431 make_label_edge (edge_cache, src, label, flags)
1432 sbitmap *edge_cache;
1437 if (GET_CODE (label) != CODE_LABEL)
1440 /* If the label was never emitted, this insn is junk, but avoid a
1441 crash trying to refer to BLOCK_FOR_INSN (label). This can happen
1442 as a result of a syntax error and a diagnostic has already been
1445 if (INSN_UID (label) == 0)
1448 make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags);
1451 /* Create the edges generated by INSN in REGION. */
1454 make_eh_edge (edge_cache, src, insn)
1455 sbitmap *edge_cache;
1459 int is_call = (GET_CODE (insn) == CALL_INSN ? EDGE_ABNORMAL_CALL : 0);
1462 handlers = reachable_handlers (insn);
1464 for (i = handlers; i; i = XEXP (i, 1))
1465 make_label_edge (edge_cache, src, XEXP (i, 0),
1466 EDGE_ABNORMAL | EDGE_EH | is_call);
1468 free_INSN_LIST_list (&handlers);
1471 /* Identify critical edges and set the bits appropriately. */
1474 mark_critical_edges ()
1476 int i, n = n_basic_blocks;
1479 /* We begin with the entry block. This is not terribly important now,
1480 but could be if a front end (Fortran) implemented alternate entry
1482 bb = ENTRY_BLOCK_PTR;
1489 /* (1) Critical edges must have a source with multiple successors. */
1490 if (bb->succ && bb->succ->succ_next)
1492 for (e = bb->succ; e; e = e->succ_next)
1494 /* (2) Critical edges must have a destination with multiple
1495 predecessors. Note that we know there is at least one
1496 predecessor -- the edge we followed to get here. */
1497 if (e->dest->pred->pred_next)
1498 e->flags |= EDGE_CRITICAL;
1500 e->flags &= ~EDGE_CRITICAL;
1505 for (e = bb->succ; e; e = e->succ_next)
1506 e->flags &= ~EDGE_CRITICAL;
1511 bb = BASIC_BLOCK (i);
1515 /* Split a block BB after insn INSN creating a new fallthru edge.
1516 Return the new edge. Note that to keep other parts of the compiler happy,
1517 this function renumbers all the basic blocks so that the new
1518 one has a number one greater than the block split. */
1521 split_block (bb, insn)
1531 /* There is no point splitting the block after its end. */
1532 if (bb->end == insn)
1535 /* Create the new structures. */
1536 new_bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*new_bb));
1537 new_edge = (edge) xcalloc (1, sizeof (*new_edge));
1540 memset (new_bb, 0, sizeof (*new_bb));
1542 new_bb->head = NEXT_INSN (insn);
1543 new_bb->end = bb->end;
1546 new_bb->succ = bb->succ;
1547 bb->succ = new_edge;
1548 new_bb->pred = new_edge;
1549 new_bb->count = bb->count;
1550 new_bb->frequency = bb->frequency;
1551 new_bb->loop_depth = bb->loop_depth;
1554 new_edge->dest = new_bb;
1555 new_edge->flags = EDGE_FALLTHRU;
1556 new_edge->probability = REG_BR_PROB_BASE;
1557 new_edge->count = bb->count;
1559 /* Redirect the src of the successor edges of bb to point to new_bb. */
1560 for (e = new_bb->succ; e; e = e->succ_next)
1563 /* Place the new block just after the block being split. */
1564 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
1566 /* Some parts of the compiler expect blocks to be number in
1567 sequential order so insert the new block immediately after the
1568 block being split.. */
1570 for (i = n_basic_blocks - 1; i > j + 1; --i)
1572 basic_block tmp = BASIC_BLOCK (i - 1);
1573 BASIC_BLOCK (i) = tmp;
1577 BASIC_BLOCK (i) = new_bb;
1580 if (GET_CODE (new_bb->head) == CODE_LABEL)
1582 /* Create the basic block note. */
1583 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK,
1585 NOTE_BASIC_BLOCK (bb_note) = new_bb;
1589 /* Create the basic block note. */
1590 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
1592 NOTE_BASIC_BLOCK (bb_note) = new_bb;
1593 new_bb->head = bb_note;
1596 update_bb_for_insn (new_bb);
1598 if (bb->global_live_at_start)
1600 new_bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1601 new_bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1602 COPY_REG_SET (new_bb->global_live_at_end, bb->global_live_at_end);
1604 /* We now have to calculate which registers are live at the end
1605 of the split basic block and at the start of the new basic
1606 block. Start with those registers that are known to be live
1607 at the end of the original basic block and get
1608 propagate_block to determine which registers are live. */
1609 COPY_REG_SET (new_bb->global_live_at_start, bb->global_live_at_end);
1610 propagate_block (new_bb, new_bb->global_live_at_start, NULL, NULL, 0);
1611 COPY_REG_SET (bb->global_live_at_end,
1612 new_bb->global_live_at_start);
1618 /* Return label in the head of basic block. Create one if it doesn't exist. */
1623 if (GET_CODE (block->head) != CODE_LABEL)
1624 block->head = emit_label_before (gen_label_rtx (), block->head);
1628 /* Return true if the block has no effect and only forwards control flow to
1629 its single destination. */
1631 forwarder_block_p (bb)
1634 rtx insn = bb->head;
1635 if (bb == EXIT_BLOCK_PTR || bb == ENTRY_BLOCK_PTR
1636 || !bb->succ || bb->succ->succ_next)
1639 while (insn != bb->end)
1641 if (active_insn_p (insn))
1643 insn = NEXT_INSN (insn);
1645 return (!active_insn_p (insn)
1646 || (GET_CODE (insn) == JUMP_INSN && onlyjump_p (insn)));
1649 /* Return nonzero if we can reach target from src by falling trought. */
1651 can_fallthru (src, target)
1652 basic_block src, target;
1654 rtx insn = src->end;
1655 rtx insn2 = target->head;
1657 if (src->index + 1 == target->index && !active_insn_p (insn2))
1658 insn2 = next_active_insn (insn2);
1659 /* ??? Later we may add code to move jump tables offline. */
1660 return next_active_insn (insn) == insn2;
1663 /* Attempt to perform edge redirection by replacing possibly complex jump
1664 instruction by unconditional jump or removing jump completely.
1665 This can apply only if all edges now point to the same block.
1667 The parameters and return values are equivalent to redirect_edge_and_branch.
1670 try_redirect_by_replacing_jump (e, target)
1674 basic_block src = e->src;
1675 rtx insn = src->end;
1680 /* Verify that all targets will be TARGET. */
1681 for (tmp = src->succ; tmp; tmp = tmp->succ_next)
1682 if (tmp->dest != target && tmp != e)
1684 if (tmp || !onlyjump_p (insn))
1687 /* Avoid removing branch with side effects. */
1688 set = single_set (insn);
1689 if (!set || side_effects_p (set))
1692 /* See if we can create the fallthru edge. */
1693 if (can_fallthru (src, target))
1695 src->end = PREV_INSN (insn);
1697 fprintf (rtl_dump_file, "Removing jump %i.\n", INSN_UID (insn));
1698 flow_delete_insn (insn);
1701 /* Selectivly unlink whole insn chain. */
1702 if (src->end != PREV_INSN (target->head))
1703 flow_delete_insn_chain (NEXT_INSN (src->end),
1704 PREV_INSN (target->head));
1706 /* If this already is simplejump, redirect it. */
1707 else if (simplejump_p (insn))
1709 if (e->dest == target)
1712 fprintf (rtl_dump_file, "Redirecting jump %i from %i to %i.\n",
1713 INSN_UID (insn), e->dest->index, target->index);
1714 redirect_jump (insn, block_label (target), 0);
1716 /* Or replace possibly complicated jump insn by simple jump insn. */
1719 rtx target_label = block_label (target);
1722 src->end = PREV_INSN (insn);
1723 src->end = emit_jump_insn_after (gen_jump (target_label), src->end);
1724 JUMP_LABEL (src->end) = target_label;
1725 LABEL_NUSES (target_label)++;
1726 if (basic_block_for_insn)
1727 set_block_for_new_insns (src->end, src);
1729 fprintf (rtl_dump_file, "Replacing insn %i by jump %i\n",
1730 INSN_UID (insn), INSN_UID (src->end));
1731 flow_delete_insn (insn);
1732 barrier = next_nonnote_insn (src->end);
1733 if (!barrier || GET_CODE (barrier) != BARRIER)
1734 emit_barrier_after (src->end);
1737 /* Keep only one edge out and set proper flags. */
1738 while (src->succ->succ_next)
1739 remove_edge (src->succ);
1742 e->flags = EDGE_FALLTHRU;
1745 e->probability = REG_BR_PROB_BASE;
1746 e->count = src->count;
1748 /* In case we've zapped an conditional jump, we need to kill the cc0
1749 setter too if available. */
1752 if (GET_CODE (insn) == JUMP_INSN)
1753 insn = prev_nonnote_insn (insn);
1754 if (sets_cc0_p (insn))
1756 if (insn == src->end)
1757 src->end = PREV_INSN (insn);
1758 flow_delete_insn (insn);
1762 /* We don't want a block to end on a line-number note since that has
1763 the potential of changing the code between -g and not -g. */
1764 while (GET_CODE (e->src->end) == NOTE
1765 && NOTE_LINE_NUMBER (e->src->end) >= 0)
1767 rtx prev = PREV_INSN (e->src->end);
1768 flow_delete_insn (e->src->end);
1772 if (e->dest != target)
1773 redirect_edge_succ (e, target);
1777 /* Attempt to change code to redirect edge E to TARGET.
1778 Don't do that on expense of adding new instructions or reordering
1781 Function can be also called with edge destionation equivalent to the
1782 TARGET. Then it should try the simplifications and do nothing if
1785 Return true if transformation suceeded. We still return flase in case
1786 E already destinated TARGET and we didn't managed to simplify instruction
1789 redirect_edge_and_branch (e, target)
1794 rtx old_label = e->dest->head;
1795 basic_block src = e->src;
1796 rtx insn = src->end;
1798 if (try_redirect_by_replacing_jump (e, target))
1800 /* Do this fast path late, as we want above code to simplify for cases
1801 where called on single edge leaving basic block containing nontrivial
1803 else if (e->dest == target)
1806 /* We can only redirect non-fallthru edges of jump insn. */
1807 if (e->flags & EDGE_FALLTHRU)
1809 if (GET_CODE (insn) != JUMP_INSN)
1812 /* Recognize a tablejump and adjust all matching cases. */
1813 if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1814 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1815 && GET_CODE (tmp) == JUMP_INSN
1816 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1817 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1821 rtx new_label = block_label (target);
1823 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1824 vec = XVEC (PATTERN (tmp), 0);
1826 vec = XVEC (PATTERN (tmp), 1);
1828 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1829 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
1831 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (Pmode, new_label);
1832 --LABEL_NUSES (old_label);
1833 ++LABEL_NUSES (new_label);
1836 /* Handle casesi dispatch insns */
1837 if ((tmp = single_set (insn)) != NULL
1838 && SET_DEST (tmp) == pc_rtx
1839 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1840 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
1841 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
1843 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (VOIDmode,
1845 --LABEL_NUSES (old_label);
1846 ++LABEL_NUSES (new_label);
1851 /* ?? We may play the games with moving the named labels from
1852 one basic block to the other in case only one computed_jump is
1854 if (computed_jump_p (insn))
1857 /* A return instruction can't be redirected. */
1858 if (returnjump_p (insn))
1861 /* If the insn doesn't go where we think, we're confused. */
1862 if (JUMP_LABEL (insn) != old_label)
1864 redirect_jump (insn, block_label (target), 0);
1868 fprintf (rtl_dump_file, "Edge %i->%i redirected to %i\n",
1869 e->src->index, e->dest->index, target->index);
1870 if (e->dest != target)
1873 /* Check whether the edge is already present. */
1874 for (s = src->succ; s; s=s->succ_next)
1875 if (s->dest == target)
1879 s->flags |= e->flags;
1880 s->probability += e->probability;
1881 s->count += e->count;
1885 redirect_edge_succ (e, target);
1890 /* Redirect edge even at the expense of creating new jump insn or
1891 basic block. Return new basic block if created, NULL otherwise.
1892 Abort if converison is impossible. */
1894 redirect_edge_and_branch_force (e, target)
1904 if (redirect_edge_and_branch (e, target))
1906 if (e->dest == target)
1908 if (e->flags & EDGE_ABNORMAL)
1910 if (!(e->flags & EDGE_FALLTHRU))
1913 e->flags &= ~EDGE_FALLTHRU;
1914 label = block_label (target);
1915 /* Case of the fallthru block. */
1916 if (!e->src->succ->succ_next)
1918 e->src->end = emit_jump_insn_after (gen_jump (label), e->src->end);
1919 JUMP_LABEL (e->src->end) = label;
1920 LABEL_NUSES (label)++;
1921 if (basic_block_for_insn)
1922 set_block_for_insn (e->src->end, e->src);
1923 emit_barrier_after (e->src->end);
1925 fprintf (rtl_dump_file,
1926 "Emitting jump insn %i to redirect edge %i->%i to %i\n",
1927 INSN_UID (e->src->end), e->src->index, e->dest->index,
1929 redirect_edge_succ (e, target);
1932 /* Redirecting fallthru edge of the conditional needs extra work. */
1935 fprintf (rtl_dump_file,
1936 "Emitting jump insn %i in new BB to redirect edge %i->%i to %i\n",
1937 INSN_UID (e->src->end), e->src->index, e->dest->index,
1940 /* Create the new structures. */
1941 new_bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*new_bb));
1942 new_edge = (edge) xcalloc (1, sizeof (*new_edge));
1945 memset (new_bb, 0, sizeof (*new_bb));
1947 new_bb->end = new_bb->head = e->src->end;
1948 new_bb->succ = NULL;
1949 new_bb->pred = new_edge;
1950 new_bb->count = e->count;
1951 new_bb->frequency = e->probability * e->src->frequency / REG_BR_PROB_BASE;
1952 new_bb->loop_depth = e->dest->loop_depth;
1954 new_edge->flags = EDGE_FALLTHRU;
1955 new_edge->probability = e->probability;
1956 new_edge->count = e->count;
1959 new_edge->src = e->src;
1960 new_edge->dest = new_bb;
1961 new_edge->succ_next = e->src->succ;
1962 e->src->succ = new_edge;
1963 new_edge->pred_next = NULL;
1965 /* Redirect old edge. */
1966 redirect_edge_succ (e, target);
1967 redirect_edge_pred (e, new_bb);
1968 e->probability = REG_BR_PROB_BASE;
1970 /* Place the new block just after the block being split. */
1971 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
1973 /* Some parts of the compiler expect blocks to be number in
1974 sequential order so insert the new block immediately after the
1975 block being split.. */
1976 j = new_edge->src->index;
1977 for (i = n_basic_blocks - 1; i > j + 1; --i)
1979 basic_block tmp = BASIC_BLOCK (i - 1);
1980 BASIC_BLOCK (i) = tmp;
1984 BASIC_BLOCK (i) = new_bb;
1987 /* Create the basic block note. */
1988 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, new_bb->head);
1989 NOTE_BASIC_BLOCK (bb_note) = new_bb;
1990 new_bb->head = bb_note;
1992 new_bb->end = emit_jump_insn_after (gen_jump (label), new_bb->head);
1993 JUMP_LABEL (new_bb->end) = label;
1994 LABEL_NUSES (label)++;
1995 if (basic_block_for_insn)
1996 set_block_for_insn (new_bb->end, new_bb);
1997 emit_barrier_after (new_bb->end);
2001 /* Split a (typically critical) edge. Return the new block.
2002 Abort on abnormal edges.
2004 ??? The code generally expects to be called on critical edges.
2005 The case of a block ending in an unconditional jump to a
2006 block with multiple predecessors is not handled optimally. */
2009 split_edge (edge_in)
2012 basic_block old_pred, bb, old_succ;
2017 /* Abnormal edges cannot be split. */
2018 if ((edge_in->flags & EDGE_ABNORMAL) != 0)
2021 old_pred = edge_in->src;
2022 old_succ = edge_in->dest;
2024 /* Create the new structures. */
2025 bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*bb));
2026 edge_out = (edge) xcalloc (1, sizeof (*edge_out));
2029 memset (bb, 0, sizeof (*bb));
2031 /* ??? This info is likely going to be out of date very soon. */
2032 if (old_succ->global_live_at_start)
2034 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
2035 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
2036 COPY_REG_SET (bb->global_live_at_start, old_succ->global_live_at_start);
2037 COPY_REG_SET (bb->global_live_at_end, old_succ->global_live_at_start);
2041 bb->succ = edge_out;
2042 bb->count = edge_in->count;
2043 bb->frequency = (edge_in->probability * edge_in->src->frequency
2044 / REG_BR_PROB_BASE);
2046 edge_in->flags &= ~EDGE_CRITICAL;
2048 edge_out->pred_next = old_succ->pred;
2049 edge_out->succ_next = NULL;
2051 edge_out->dest = old_succ;
2052 edge_out->flags = EDGE_FALLTHRU;
2053 edge_out->probability = REG_BR_PROB_BASE;
2054 edge_out->count = edge_in->count;
2056 old_succ->pred = edge_out;
2058 /* Tricky case -- if there existed a fallthru into the successor
2059 (and we're not it) we must add a new unconditional jump around
2060 the new block we're actually interested in.
2062 Further, if that edge is critical, this means a second new basic
2063 block must be created to hold it. In order to simplify correct
2064 insn placement, do this before we touch the existing basic block
2065 ordering for the block we were really wanting. */
2066 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
2069 for (e = edge_out->pred_next; e; e = e->pred_next)
2070 if (e->flags & EDGE_FALLTHRU)
2075 basic_block jump_block;
2078 if ((e->flags & EDGE_CRITICAL) == 0
2079 && e->src != ENTRY_BLOCK_PTR)
2081 /* Non critical -- we can simply add a jump to the end
2082 of the existing predecessor. */
2083 jump_block = e->src;
2087 /* We need a new block to hold the jump. The simplest
2088 way to do the bulk of the work here is to recursively
2090 jump_block = split_edge (e);
2091 e = jump_block->succ;
2094 /* Now add the jump insn ... */
2095 pos = emit_jump_insn_after (gen_jump (old_succ->head),
2097 jump_block->end = pos;
2098 if (basic_block_for_insn)
2099 set_block_for_insn (pos, jump_block);
2100 emit_barrier_after (pos);
2102 /* ... let jump know that label is in use, ... */
2103 JUMP_LABEL (pos) = old_succ->head;
2104 ++LABEL_NUSES (old_succ->head);
2106 /* ... and clear fallthru on the outgoing edge. */
2107 e->flags &= ~EDGE_FALLTHRU;
2109 /* Continue splitting the interesting edge. */
2113 /* Place the new block just in front of the successor. */
2114 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
2115 if (old_succ == EXIT_BLOCK_PTR)
2116 j = n_basic_blocks - 1;
2118 j = old_succ->index;
2119 for (i = n_basic_blocks - 1; i > j; --i)
2121 basic_block tmp = BASIC_BLOCK (i - 1);
2122 BASIC_BLOCK (i) = tmp;
2125 BASIC_BLOCK (i) = bb;
2128 /* Create the basic block note.
2130 Where we place the note can have a noticable impact on the generated
2131 code. Consider this cfg:
2141 If we need to insert an insn on the edge from block 0 to block 1,
2142 we want to ensure the instructions we insert are outside of any
2143 loop notes that physically sit between block 0 and block 1. Otherwise
2144 we confuse the loop optimizer into thinking the loop is a phony. */
2145 if (old_succ != EXIT_BLOCK_PTR
2146 && PREV_INSN (old_succ->head)
2147 && GET_CODE (PREV_INSN (old_succ->head)) == NOTE
2148 && NOTE_LINE_NUMBER (PREV_INSN (old_succ->head)) == NOTE_INSN_LOOP_BEG)
2149 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
2150 PREV_INSN (old_succ->head));
2151 else if (old_succ != EXIT_BLOCK_PTR)
2152 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, old_succ->head);
2154 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
2155 NOTE_BASIC_BLOCK (bb_note) = bb;
2156 bb->head = bb->end = bb_note;
2158 /* For non-fallthry edges, we must adjust the predecessor's
2159 jump instruction to target our new block. */
2160 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
2162 if (!redirect_edge_and_branch (edge_in, bb))
2166 redirect_edge_succ (edge_in, bb);
2171 /* Queue instructions for insertion on an edge between two basic blocks.
2172 The new instructions and basic blocks (if any) will not appear in the
2173 CFG until commit_edge_insertions is called. */
2176 insert_insn_on_edge (pattern, e)
2180 /* We cannot insert instructions on an abnormal critical edge.
2181 It will be easier to find the culprit if we die now. */
2182 if ((e->flags & (EDGE_ABNORMAL|EDGE_CRITICAL))
2183 == (EDGE_ABNORMAL|EDGE_CRITICAL))
2186 if (e->insns == NULL_RTX)
2189 push_to_sequence (e->insns);
2191 emit_insn (pattern);
2193 e->insns = get_insns ();
2197 /* Update the CFG for the instructions queued on edge E. */
2200 commit_one_edge_insertion (e)
2203 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
2206 /* Pull the insns off the edge now since the edge might go away. */
2208 e->insns = NULL_RTX;
2210 /* Figure out where to put these things. If the destination has
2211 one predecessor, insert there. Except for the exit block. */
2212 if (e->dest->pred->pred_next == NULL
2213 && e->dest != EXIT_BLOCK_PTR)
2217 /* Get the location correct wrt a code label, and "nice" wrt
2218 a basic block note, and before everything else. */
2220 if (GET_CODE (tmp) == CODE_LABEL)
2221 tmp = NEXT_INSN (tmp);
2222 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
2223 tmp = NEXT_INSN (tmp);
2224 if (tmp == bb->head)
2227 after = PREV_INSN (tmp);
2230 /* If the source has one successor and the edge is not abnormal,
2231 insert there. Except for the entry block. */
2232 else if ((e->flags & EDGE_ABNORMAL) == 0
2233 && e->src->succ->succ_next == NULL
2234 && e->src != ENTRY_BLOCK_PTR)
2237 /* It is possible to have a non-simple jump here. Consider a target
2238 where some forms of unconditional jumps clobber a register. This
2239 happens on the fr30 for example.
2241 We know this block has a single successor, so we can just emit
2242 the queued insns before the jump. */
2243 if (GET_CODE (bb->end) == JUMP_INSN)
2249 /* We'd better be fallthru, or we've lost track of what's what. */
2250 if ((e->flags & EDGE_FALLTHRU) == 0)
2257 /* Otherwise we must split the edge. */
2260 bb = split_edge (e);
2264 /* Now that we've found the spot, do the insertion. */
2266 /* Set the new block number for these insns, if structure is allocated. */
2267 if (basic_block_for_insn)
2270 for (i = insns; i != NULL_RTX; i = NEXT_INSN (i))
2271 set_block_for_insn (i, bb);
2276 emit_insns_before (insns, before);
2277 if (before == bb->head)
2280 last = prev_nonnote_insn (before);
2284 last = emit_insns_after (insns, after);
2285 if (after == bb->end)
2289 if (returnjump_p (last))
2291 /* ??? Remove all outgoing edges from BB and add one for EXIT.
2292 This is not currently a problem because this only happens
2293 for the (single) epilogue, which already has a fallthru edge
2297 if (e->dest != EXIT_BLOCK_PTR
2298 || e->succ_next != NULL
2299 || (e->flags & EDGE_FALLTHRU) == 0)
2301 e->flags &= ~EDGE_FALLTHRU;
2303 emit_barrier_after (last);
2307 flow_delete_insn (before);
2309 else if (GET_CODE (last) == JUMP_INSN)
2311 find_sub_basic_blocks (bb);
2314 /* Update the CFG for all queued instructions. */
2317 commit_edge_insertions ()
2322 #ifdef ENABLE_CHECKING
2323 verify_flow_info ();
2327 bb = ENTRY_BLOCK_PTR;
2332 for (e = bb->succ; e; e = next)
2334 next = e->succ_next;
2336 commit_one_edge_insertion (e);
2339 if (++i >= n_basic_blocks)
2341 bb = BASIC_BLOCK (i);
2345 /* Add fake edges to the function exit for any non constant calls in
2346 the bitmap of blocks specified by BLOCKS or to the whole CFG if
2347 BLOCKS is zero. Return the nuber of blocks that were split. */
2350 flow_call_edges_add (blocks)
2354 int blocks_split = 0;
2358 /* Map bb indicies into basic block pointers since split_block
2359 will renumber the basic blocks. */
2361 bbs = xmalloc (n_basic_blocks * sizeof (*bbs));
2365 for (i = 0; i < n_basic_blocks; i++)
2366 bbs[bb_num++] = BASIC_BLOCK (i);
2370 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
2372 bbs[bb_num++] = BASIC_BLOCK (i);
2377 /* Now add fake edges to the function exit for any non constant
2378 calls since there is no way that we can determine if they will
2381 for (i = 0; i < bb_num; i++)
2383 basic_block bb = bbs[i];
2387 for (insn = bb->end; ; insn = prev_insn)
2389 prev_insn = PREV_INSN (insn);
2390 if (GET_CODE (insn) == CALL_INSN && ! CONST_CALL_P (insn))
2394 /* Note that the following may create a new basic block
2395 and renumber the existing basic blocks. */
2396 e = split_block (bb, insn);
2400 make_edge (NULL, bb, EXIT_BLOCK_PTR, EDGE_FAKE);
2402 if (insn == bb->head)
2408 verify_flow_info ();
2411 return blocks_split;
2414 /* Find unreachable blocks. An unreachable block will have NULL in
2415 block->aux, a non-NULL value indicates the block is reachable. */
2418 find_unreachable_blocks ()
2422 basic_block *tos, *worklist;
2425 tos = worklist = (basic_block *) xmalloc (sizeof (basic_block) * n);
2427 /* Use basic_block->aux as a marker. Clear them all. */
2429 for (i = 0; i < n; ++i)
2430 BASIC_BLOCK (i)->aux = NULL;
2432 /* Add our starting points to the worklist. Almost always there will
2433 be only one. It isn't inconcievable that we might one day directly
2434 support Fortran alternate entry points. */
2436 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
2440 /* Mark the block with a handy non-null value. */
2444 /* Iterate: find everything reachable from what we've already seen. */
2446 while (tos != worklist)
2448 basic_block b = *--tos;
2450 for (e = b->succ; e; e = e->succ_next)
2461 /* Delete all unreachable basic blocks. */
2463 delete_unreachable_blocks ()
2467 find_unreachable_blocks ();
2469 /* Delete all unreachable basic blocks. Count down so that we
2470 don't interfere with the block renumbering that happens in
2471 flow_delete_block. */
2473 for (i = n_basic_blocks - 1; i >= 0; --i)
2475 basic_block b = BASIC_BLOCK (i);
2478 /* This block was found. Tidy up the mark. */
2481 flow_delete_block (b);
2484 tidy_fallthru_edges ();
2487 /* Return true if NOTE is not one of the ones that must be kept paired,
2488 so that we may simply delete them. */
2491 can_delete_note_p (note)
2494 return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED
2495 || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK);
2498 /* Unlink a chain of insns between START and FINISH, leaving notes
2499 that must be paired. */
2502 flow_delete_insn_chain (start, finish)
2505 /* Unchain the insns one by one. It would be quicker to delete all
2506 of these with a single unchaining, rather than one at a time, but
2507 we need to keep the NOTE's. */
2513 next = NEXT_INSN (start);
2514 if (GET_CODE (start) == NOTE && !can_delete_note_p (start))
2516 else if (GET_CODE (start) == CODE_LABEL
2517 && ! can_delete_label_p (start))
2519 const char *name = LABEL_NAME (start);
2520 PUT_CODE (start, NOTE);
2521 NOTE_LINE_NUMBER (start) = NOTE_INSN_DELETED_LABEL;
2522 NOTE_SOURCE_FILE (start) = name;
2525 next = flow_delete_insn (start);
2527 if (start == finish)
2533 /* Delete the insns in a (non-live) block. We physically delete every
2534 non-deleted-note insn, and update the flow graph appropriately.
2536 Return nonzero if we deleted an exception handler. */
2538 /* ??? Preserving all such notes strikes me as wrong. It would be nice
2539 to post-process the stream to remove empty blocks, loops, ranges, etc. */
2542 flow_delete_block (b)
2545 int deleted_handler = 0;
2548 /* If the head of this block is a CODE_LABEL, then it might be the
2549 label for an exception handler which can't be reached.
2551 We need to remove the label from the exception_handler_label list
2552 and remove the associated NOTE_INSN_EH_REGION_BEG and
2553 NOTE_INSN_EH_REGION_END notes. */
2557 never_reached_warning (insn);
2559 if (GET_CODE (insn) == CODE_LABEL)
2560 maybe_remove_eh_handler (insn);
2562 /* Include any jump table following the basic block. */
2564 if (GET_CODE (end) == JUMP_INSN
2565 && (tmp = JUMP_LABEL (end)) != NULL_RTX
2566 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
2567 && GET_CODE (tmp) == JUMP_INSN
2568 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
2569 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
2572 /* Include any barrier that may follow the basic block. */
2573 tmp = next_nonnote_insn (end);
2574 if (tmp && GET_CODE (tmp) == BARRIER)
2577 /* Selectively delete the entire chain. */
2578 flow_delete_insn_chain (insn, end);
2580 /* Remove the edges into and out of this block. Note that there may
2581 indeed be edges in, if we are removing an unreachable loop. */
2585 for (e = b->pred; e; e = next)
2587 for (q = &e->src->succ; *q != e; q = &(*q)->succ_next)
2590 next = e->pred_next;
2594 for (e = b->succ; e; e = next)
2596 for (q = &e->dest->pred; *q != e; q = &(*q)->pred_next)
2599 next = e->succ_next;
2608 /* Remove the basic block from the array, and compact behind it. */
2611 return deleted_handler;
2614 /* Remove block B from the basic block array and compact behind it. */
2620 int i, n = n_basic_blocks;
2622 for (i = b->index; i + 1 < n; ++i)
2624 basic_block x = BASIC_BLOCK (i + 1);
2625 BASIC_BLOCK (i) = x;
2629 basic_block_info->num_elements--;
2633 /* Delete INSN by patching it out. Return the next insn. */
2636 flow_delete_insn (insn)
2639 rtx prev = PREV_INSN (insn);
2640 rtx next = NEXT_INSN (insn);
2643 PREV_INSN (insn) = NULL_RTX;
2644 NEXT_INSN (insn) = NULL_RTX;
2645 INSN_DELETED_P (insn) = 1;
2648 NEXT_INSN (prev) = next;
2650 PREV_INSN (next) = prev;
2652 set_last_insn (prev);
2654 if (GET_CODE (insn) == CODE_LABEL)
2655 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2657 /* If deleting a jump, decrement the use count of the label. Deleting
2658 the label itself should happen in the normal course of block merging. */
2659 if (GET_CODE (insn) == JUMP_INSN
2660 && JUMP_LABEL (insn)
2661 && GET_CODE (JUMP_LABEL (insn)) == CODE_LABEL)
2662 LABEL_NUSES (JUMP_LABEL (insn))--;
2664 /* Also if deleting an insn that references a label. */
2665 else if ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX
2666 && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
2667 LABEL_NUSES (XEXP (note, 0))--;
2669 if (GET_CODE (insn) == JUMP_INSN
2670 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
2671 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
2673 rtx pat = PATTERN (insn);
2674 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
2675 int len = XVECLEN (pat, diff_vec_p);
2678 for (i = 0; i < len; i++)
2679 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
2685 /* True if a given label can be deleted. */
2688 can_delete_label_p (label)
2693 if (LABEL_PRESERVE_P (label))
2696 for (x = forced_labels; x; x = XEXP (x, 1))
2697 if (label == XEXP (x, 0))
2699 for (x = label_value_list; x; x = XEXP (x, 1))
2700 if (label == XEXP (x, 0))
2702 for (x = exception_handler_labels; x; x = XEXP (x, 1))
2703 if (label == XEXP (x, 0))
2706 /* User declared labels must be preserved. */
2707 if (LABEL_NAME (label) != 0)
2714 tail_recursion_label_p (label)
2719 for (x = tail_recursion_label_list; x; x = XEXP (x, 1))
2720 if (label == XEXP (x, 0))
2726 /* Blocks A and B are to be merged into a single block A. The insns
2727 are already contiguous, hence `nomove'. */
2730 merge_blocks_nomove (a, b)
2734 rtx b_head, b_end, a_end;
2735 rtx del_first = NULL_RTX, del_last = NULL_RTX;
2738 /* If there was a CODE_LABEL beginning B, delete it. */
2741 if (GET_CODE (b_head) == CODE_LABEL)
2743 /* Detect basic blocks with nothing but a label. This can happen
2744 in particular at the end of a function. */
2745 if (b_head == b_end)
2747 del_first = del_last = b_head;
2748 b_head = NEXT_INSN (b_head);
2751 /* Delete the basic block note. */
2752 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
2754 if (b_head == b_end)
2759 b_head = NEXT_INSN (b_head);
2762 /* If there was a jump out of A, delete it. */
2764 if (GET_CODE (a_end) == JUMP_INSN)
2768 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
2769 if (GET_CODE (prev) != NOTE
2770 || NOTE_LINE_NUMBER (prev) == NOTE_INSN_BASIC_BLOCK
2777 /* If this was a conditional jump, we need to also delete
2778 the insn that set cc0. */
2779 if (prev && sets_cc0_p (prev))
2782 prev = prev_nonnote_insn (prev);
2791 else if (GET_CODE (NEXT_INSN (a_end)) == BARRIER)
2792 del_first = NEXT_INSN (a_end);
2794 /* Delete everything marked above as well as crap that might be
2795 hanging out between the two blocks. */
2796 flow_delete_insn_chain (del_first, del_last);
2798 /* Normally there should only be one successor of A and that is B, but
2799 partway though the merge of blocks for conditional_execution we'll
2800 be merging a TEST block with THEN and ELSE successors. Free the
2801 whole lot of them and hope the caller knows what they're doing. */
2803 remove_edge (a->succ);
2805 /* Adjust the edges out of B for the new owner. */
2806 for (e = b->succ; e; e = e->succ_next)
2810 /* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */
2811 b->pred = b->succ = NULL;
2813 /* Reassociate the insns of B with A. */
2816 if (basic_block_for_insn)
2818 BLOCK_FOR_INSN (b_head) = a;
2819 while (b_head != b_end)
2821 b_head = NEXT_INSN (b_head);
2822 BLOCK_FOR_INSN (b_head) = a;
2832 /* Blocks A and B are to be merged into a single block. A has no incoming
2833 fallthru edge, so it can be moved before B without adding or modifying
2834 any jumps (aside from the jump from A to B). */
2837 merge_blocks_move_predecessor_nojumps (a, b)
2840 rtx start, end, barrier;
2846 barrier = next_nonnote_insn (end);
2847 if (GET_CODE (barrier) != BARRIER)
2849 flow_delete_insn (barrier);
2851 /* Move block and loop notes out of the chain so that we do not
2852 disturb their order.
2854 ??? A better solution would be to squeeze out all the non-nested notes
2855 and adjust the block trees appropriately. Even better would be to have
2856 a tighter connection between block trees and rtl so that this is not
2858 start = squeeze_notes (start, end);
2860 /* Scramble the insn chain. */
2861 if (end != PREV_INSN (b->head))
2862 reorder_insns (start, end, PREV_INSN (b->head));
2866 fprintf (rtl_dump_file, "Moved block %d before %d and merged.\n",
2867 a->index, b->index);
2870 /* Swap the records for the two blocks around. Although we are deleting B,
2871 A is now where B was and we want to compact the BB array from where
2873 BASIC_BLOCK (a->index) = b;
2874 BASIC_BLOCK (b->index) = a;
2876 a->index = b->index;
2879 /* Now blocks A and B are contiguous. Merge them. */
2880 merge_blocks_nomove (a, b);
2885 /* Blocks A and B are to be merged into a single block. B has no outgoing
2886 fallthru edge, so it can be moved after A without adding or modifying
2887 any jumps (aside from the jump from A to B). */
2890 merge_blocks_move_successor_nojumps (a, b)
2893 rtx start, end, barrier;
2897 barrier = NEXT_INSN (end);
2899 /* Recognize a jump table following block B. */
2901 && GET_CODE (barrier) == CODE_LABEL
2902 && NEXT_INSN (barrier)
2903 && GET_CODE (NEXT_INSN (barrier)) == JUMP_INSN
2904 && (GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_VEC
2905 || GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_DIFF_VEC))
2907 end = NEXT_INSN (barrier);
2908 barrier = NEXT_INSN (end);
2911 /* There had better have been a barrier there. Delete it. */
2912 if (barrier && GET_CODE (barrier) == BARRIER)
2913 flow_delete_insn (barrier);
2915 /* Move block and loop notes out of the chain so that we do not
2916 disturb their order.
2918 ??? A better solution would be to squeeze out all the non-nested notes
2919 and adjust the block trees appropriately. Even better would be to have
2920 a tighter connection between block trees and rtl so that this is not
2922 start = squeeze_notes (start, end);
2924 /* Scramble the insn chain. */
2925 reorder_insns (start, end, a->end);
2927 /* Now blocks A and B are contiguous. Merge them. */
2928 merge_blocks_nomove (a, b);
2932 fprintf (rtl_dump_file, "Moved block %d after %d and merged.\n",
2933 b->index, a->index);
2939 /* Attempt to merge basic blocks that are potentially non-adjacent.
2940 Return true iff the attempt succeeded. */
2943 merge_blocks (e, b, c, mode)
2948 /* If C has a tail recursion label, do not merge. There is no
2949 edge recorded from the call_placeholder back to this label, as
2950 that would make optimize_sibling_and_tail_recursive_calls more
2951 complex for no gain. */
2952 if (GET_CODE (c->head) == CODE_LABEL
2953 && tail_recursion_label_p (c->head))
2956 /* If B has a fallthru edge to C, no need to move anything. */
2957 if (e->flags & EDGE_FALLTHRU)
2959 merge_blocks_nomove (b, c);
2963 fprintf (rtl_dump_file, "Merged %d and %d without moving.\n",
2964 b->index, c->index);
2969 /* Otherwise we will need to move code around. Do that only if expensive
2970 transformations are allowed. */
2971 else if (mode & CLEANUP_EXPENSIVE)
2973 edge tmp_edge, c_fallthru_edge;
2974 int c_has_outgoing_fallthru;
2975 int b_has_incoming_fallthru;
2977 /* We must make sure to not munge nesting of exception regions,
2978 lexical blocks, and loop notes.
2980 The first is taken care of by requiring that the active eh
2981 region at the end of one block always matches the active eh
2982 region at the beginning of the next block.
2984 The later two are taken care of by squeezing out all the notes. */
2986 /* ??? A throw/catch edge (or any abnormal edge) should be rarely
2987 executed and we may want to treat blocks which have two out
2988 edges, one normal, one abnormal as only having one edge for
2989 block merging purposes. */
2991 for (tmp_edge = c->succ; tmp_edge; tmp_edge = tmp_edge->succ_next)
2992 if (tmp_edge->flags & EDGE_FALLTHRU)
2994 c_has_outgoing_fallthru = (tmp_edge != NULL);
2995 c_fallthru_edge = tmp_edge;
2997 for (tmp_edge = b->pred; tmp_edge; tmp_edge = tmp_edge->pred_next)
2998 if (tmp_edge->flags & EDGE_FALLTHRU)
3000 b_has_incoming_fallthru = (tmp_edge != NULL);
3002 /* If B does not have an incoming fallthru, then it can be moved
3003 immediately before C without introducing or modifying jumps.
3004 C cannot be the first block, so we do not have to worry about
3005 accessing a non-existent block. */
3006 if (! b_has_incoming_fallthru)
3007 return merge_blocks_move_predecessor_nojumps (b, c);
3009 /* Otherwise, we're going to try to move C after B. If C does
3010 not have an outgoing fallthru, then it can be moved
3011 immediately after B without introducing or modifying jumps. */
3012 if (! c_has_outgoing_fallthru)
3013 return merge_blocks_move_successor_nojumps (b, c);
3015 /* Otherwise, we'll need to insert an extra jump, and possibly
3016 a new block to contain it. We can't redirect to EXIT_BLOCK_PTR,
3017 as we don't have explicit return instructions before epilogues
3018 are generated, so give up on that case. */
3020 if (c_fallthru_edge->dest != EXIT_BLOCK_PTR
3021 && merge_blocks_move_successor_nojumps (b, c))
3023 basic_block target = c_fallthru_edge->dest;
3027 /* This is a dirty hack to avoid code duplication.
3029 Set edge to point to wrong basic block, so
3030 redirect_edge_and_branch_force will do the trick
3031 and rewire edge back to the original location. */
3032 redirect_edge_succ (c_fallthru_edge, ENTRY_BLOCK_PTR);
3033 new = redirect_edge_and_branch_force (c_fallthru_edge, target);
3035 /* We've just created barrier, but other barrier is already present
3036 in the stream. Avoid duplicate. */
3037 barrier = next_nonnote_insn (new ? new->end : b->end);
3038 if (GET_CODE (barrier) != BARRIER)
3040 flow_delete_insn (barrier);
3048 /* Simplify conditional jump around an jump.
3049 Return nonzero in case optimization matched. */
3052 try_simplify_condjump (src)
3055 basic_block final_block, next_block;
3056 rtx insn = src->end;
3057 edge branch, fallthru;
3059 /* Verify that there are exactly two successors. */
3060 if (!src->succ || !src->succ->succ_next || src->succ->succ_next->succ_next
3061 || !any_condjump_p (insn))
3064 fallthru = FALLTHRU_EDGE (src);
3066 /* Following block must be simple forwarder block with single
3067 entry and must not be last in the stream. */
3068 next_block = fallthru->dest;
3069 if (!forwarder_block_p (next_block)
3070 || next_block->pred->pred_next
3071 || next_block->index == n_basic_blocks - 1)
3074 /* The branch must target to block afterwards. */
3075 final_block = BASIC_BLOCK (next_block->index + 1);
3077 branch = BRANCH_EDGE (src);
3079 if (branch->dest != final_block)
3082 /* Avoid jump.c from being overactive on removin ureachable insns. */
3083 LABEL_NUSES (JUMP_LABEL (insn))++;
3084 if (!invert_jump (insn, block_label (next_block->succ->dest), 1))
3086 LABEL_NUSES (JUMP_LABEL (insn))--;
3090 fprintf (rtl_dump_file, "Simplifying condjump %i around jump %i\n",
3091 INSN_UID (insn), INSN_UID (next_block->end));
3093 redirect_edge_succ (branch, final_block);
3094 redirect_edge_succ (fallthru, next_block->succ->dest);
3096 branch->flags |= EDGE_FALLTHRU;
3097 fallthru->flags &= ~EDGE_FALLTHRU;
3099 flow_delete_block (next_block);
3103 /* Attempt to forward edges leaving basic block B.
3104 Return nonzero if sucessfull. */
3107 try_forward_edges (b)
3112 for (e = b->succ; e; e = e->succ_next)
3114 basic_block target = e->dest, first = e->dest;
3117 /* Look for the real destination of jump.
3118 Avoid inifinite loop in the infinite empty loop by counting
3119 up to n_basic_blocks. */
3120 while (forwarder_block_p (target)
3121 && target->succ->dest != EXIT_BLOCK_PTR
3122 && counter < n_basic_blocks)
3124 /* Bypass trivial infinite loops. */
3125 if (target == target->succ->dest)
3126 counter = n_basic_blocks;
3127 target = target->succ->dest, counter++;
3130 if (target != first && counter < n_basic_blocks
3131 && redirect_edge_and_branch (e, target))
3133 while (first != target)
3135 first->count -= e->count;
3136 first->succ->count -= e->count;
3137 first->frequency -= ((e->probability * b->frequency
3138 + REG_BR_PROB_BASE / 2)
3139 / REG_BR_PROB_BASE);
3140 first = first->succ->dest;
3142 /* We've possibly removed the edge. */
3146 else if (rtl_dump_file && counter == n_basic_blocks)
3147 fprintf (rtl_dump_file, "Infinite loop in BB %i.\n", target->index);
3148 else if (rtl_dump_file && first != target)
3149 fprintf (rtl_dump_file,
3150 "Forwarding edge %i->%i to %i failed.\n", b->index,
3151 e->dest->index, target->index);
3156 /* Compare the instructions before end of B1 and B2
3157 to find an opportunity for cross jumping.
3158 (This means detecting identical sequences of insns)
3159 Find the longest possible equivalent sequences
3160 and store the first insns of those sequences into *F1 and *F2
3161 and return length of that sequence.
3163 To simplify callers of this function, in the
3164 all instructions were matched, allways store bb->head. */
3167 flow_find_cross_jump (mode, bb1, bb2, f1, f2)
3169 basic_block bb1, bb2;
3172 rtx i1 = onlyjump_p (bb1->end) ? PREV_INSN (bb1->end): bb1->end;
3173 rtx i2 = onlyjump_p (bb2->end) ? PREV_INSN (bb2->end): bb2->end;
3177 rtx last1 = bb1->end, last2 = bb2->end;
3178 rtx afterlast1 = bb1->end, afterlast2 = bb2->end;
3180 /* In case basic block ends by nontrivial jump instruction, count it as
3181 an instruction. Do not count an unconditional jump, as it will be
3182 removed by basic_block reordering pass in case it is on the common
3184 if (bb1->succ->succ_next && bb1->end != i1)
3187 for (;i1 != bb1->head; i1 = PREV_INSN (i1))
3190 if (GET_CODE (i1) == NOTE)
3192 while ((GET_CODE (i2) == NOTE && i2 != bb2->head))
3193 i2 = PREV_INSN (i2);
3195 if (GET_CODE (i1) != GET_CODE (i2))
3201 /* If this is a CALL_INSN, compare register usage information.
3202 If we don't check this on stack register machines, the two
3203 CALL_INSNs might be merged leaving reg-stack.c with mismatching
3204 numbers of stack registers in the same basic block.
3205 If we don't check this on machines with delay slots, a delay slot may
3206 be filled that clobbers a parameter expected by the subroutine.
3208 ??? We take the simple route for now and assume that if they're
3209 equal, they were constructed identically. */
3211 if (GET_CODE (i1) == CALL_INSN
3212 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
3213 CALL_INSN_FUNCTION_USAGE (i2)))
3217 /* If cross_jump_death_matters is not 0, the insn's mode
3218 indicates whether or not the insn contains any stack-like
3221 if (!lose && (mode & CLEANUP_POST_REGSTACK ) && stack_regs_mentioned (i1))
3223 /* If register stack conversion has already been done, then
3224 death notes must also be compared before it is certain that
3225 the two instruction streams match. */
3228 HARD_REG_SET i1_regset, i2_regset;
3230 CLEAR_HARD_REG_SET (i1_regset);
3231 CLEAR_HARD_REG_SET (i2_regset);
3233 for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
3234 if (REG_NOTE_KIND (note) == REG_DEAD
3235 && STACK_REG_P (XEXP (note, 0)))
3236 SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
3238 for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
3239 if (REG_NOTE_KIND (note) == REG_DEAD
3240 && STACK_REG_P (XEXP (note, 0)))
3241 SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
3243 GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
3252 if (lose || GET_CODE (p1) != GET_CODE (p2)
3253 || ! rtx_renumbered_equal_p (p1, p2))
3255 /* The following code helps take care of G++ cleanups. */
3259 if (!lose && GET_CODE (p1) == GET_CODE (p2)
3260 && ((equiv1 = find_reg_note (i1, REG_EQUAL, NULL_RTX)) != 0
3261 || (equiv1 = find_reg_note (i1, REG_EQUIV, NULL_RTX)) != 0)
3262 && ((equiv2 = find_reg_note (i2, REG_EQUAL, NULL_RTX)) != 0
3263 || (equiv2 = find_reg_note (i2, REG_EQUIV, NULL_RTX)) != 0)
3264 /* If the equivalences are not to a constant, they may
3265 reference pseudos that no longer exist, so we can't
3267 && CONSTANT_P (XEXP (equiv1, 0))
3268 && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
3270 rtx s1 = single_set (i1);
3271 rtx s2 = single_set (i2);
3272 if (s1 != 0 && s2 != 0
3273 && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
3275 validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
3276 validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
3277 if (! rtx_renumbered_equal_p (p1, p2))
3279 else if (apply_change_group ())
3284 /* Insns fail to match; cross jumping is limited to the following
3288 /* Don't allow the insn after a compare to be shared by
3289 cross-jumping unless the compare is also shared.
3290 Here, if either of these non-matching insns is a compare,
3291 exclude the following insn from possible cross-jumping. */
3292 if (sets_cc0_p (p1) || sets_cc0_p (p2))
3293 last1 = afterlast1, last2 = afterlast2, ninsns--;
3299 if (GET_CODE (p1) != USE && GET_CODE (p1) != CLOBBER)
3301 /* Ok, this insn is potentially includable in a cross-jump here. */
3302 afterlast1 = last1, afterlast2 = last2;
3303 last1 = i1, last2 = i2;
3309 i2 = PREV_INSN (i2);
3312 /* Skip the notes to reach potential head of basic block. */
3313 while (last1 != bb1->head && GET_CODE (PREV_INSN (last1)) == NOTE)
3314 last1 = PREV_INSN (last1);
3315 if (last1 != bb1->head && GET_CODE (PREV_INSN (last1)) == CODE_LABEL)
3316 last1 = PREV_INSN (last1);
3317 while (last2 != bb2->head && GET_CODE (PREV_INSN (last2)) == NOTE)
3318 last2 = PREV_INSN (last2);
3319 if (last2 != bb2->head && GET_CODE (PREV_INSN (last2)) == CODE_LABEL)
3320 last2 = PREV_INSN (last2);
3327 /* Return true iff outgoing edges of BB1 and BB2 match, together with
3328 the branch instruction. This means that if we commonize the control
3329 flow before end of the basic block, the semantic remains unchanged.
3331 Assume that at least one outgoing edge is forwarded to the same
3334 outgoing_edges_match (bb1, bb2)
3338 /* bb1 has one succesor, so we are seeing unconditional jump. */
3339 if (bb1->succ && !bb1->succ->succ_next)
3340 return (bb2->succ && !bb2->succ->succ_next);
3342 /* Match conditional jumps - this may get tricky when fallthru and branch
3343 edges are crossed. */
3344 if (bb1->succ && bb1->succ->succ_next && !bb1->succ->succ_next->succ_next
3345 && any_condjump_p (bb1->end))
3347 edge b1, f1, b2, f2;
3348 bool reverse, match;
3349 rtx set1, set2, cond1, cond2;
3350 enum rtx_code code1, code2;
3352 if (!bb2->succ || !bb2->succ->succ_next
3353 || bb1->succ->succ_next->succ_next || !any_condjump_p (bb2->end))
3355 b1 = BRANCH_EDGE (bb1);
3356 b2 = BRANCH_EDGE (bb2);
3357 f1 = FALLTHRU_EDGE (bb1);
3358 f2 = FALLTHRU_EDGE (bb2);
3360 /* Get around possible forwarders on fallthru edges. Other cases
3361 should be optimized out already. */
3362 if (forwarder_block_p (f1->dest))
3363 f1 = f1->dest->succ;
3364 if (forwarder_block_p (f2->dest))
3365 f2 = f2->dest->succ;
3367 /* To simplify use of this function, return false if there are
3368 unneeded forwarder blocks. These will get eliminated later
3369 during cleanup_cfg. */
3370 if (forwarder_block_p (f1->dest)
3371 || forwarder_block_p (f2->dest)
3372 || forwarder_block_p (b1->dest)
3373 || forwarder_block_p (b2->dest))
3376 if (f1->dest == f2->dest && b1->dest == b2->dest)
3378 else if (f1->dest == b2->dest && b1->dest == f2->dest)
3383 set1 = pc_set (bb1->end);
3384 set2 = pc_set (bb2->end);
3385 if ((XEXP (SET_SRC (set1), 1) == pc_rtx)
3386 != (XEXP (SET_SRC (set2), 1) == pc_rtx))
3389 cond1 = XEXP (SET_SRC (set1), 0);
3390 cond2 = XEXP (SET_SRC (set2), 0);
3391 code1 = GET_CODE (cond1);
3393 code2 = reversed_comparison_code (cond2, bb2->end);
3395 code2 = GET_CODE (cond2);
3397 /* See if we don have (cross) match in the codes and operands. */
3398 match = ((code1 == code2
3399 && rtx_renumbered_equal_p (XEXP (cond1, 0), XEXP (cond2, 0))
3400 && rtx_renumbered_equal_p (XEXP (cond1, 1), XEXP (cond2, 1)))
3401 || (code1 == swap_condition (code2)
3402 && rtx_renumbered_equal_p (XEXP (cond1, 1),
3404 && rtx_renumbered_equal_p (XEXP (cond1, 0),
3406 /* In case of returning true, we will commonize the flow.
3407 This also means, that both branches will contain only single
3408 branch prediction algorithm. To match require resulting branch
3409 to be still well predictable. */
3410 if (match && !optimize_size)
3414 note1 = find_reg_note (bb1->end, REG_BR_PROB, 0);
3415 note2 = find_reg_note (bb2->end, REG_BR_PROB, 0);
3416 if (!note1 || !note2)
3418 prob1 = INTVAL (XEXP (note1, 0));
3419 prob2 = INTVAL (XEXP (note2, 0));
3421 prob2 = REG_BR_PROB_BASE - prob2;
3423 /* ??? Later we should use basic block frequency to allow merging
3424 in the infrequent blocks, but at the moment it is not
3425 available when cleanup_cfg is run. */
3426 if (abs (prob1 - prob2) > REG_BR_PROB_BASE / 90)
3429 if (rtl_dump_file && match)
3430 fprintf (rtl_dump_file, "Conditionals in bb %i and %i match.\n",
3431 bb1->index, bb2->index);
3434 /* ??? We can handle computed jumps too. This may be important for
3435 inlined functions containing switch statements. Also jumps w/o
3436 fallthru edges can be handled by simply matching whole insn. */
3440 /* Assume that e1 and e2 are the edges from the same basic block.
3441 Attempt to find common code on both paths and forward control flow
3442 from the first path to second if such exist. */
3444 try_crossjump_to_edge (mode, e1, e2)
3449 basic_block redirect_to;
3450 rtx newpos1, newpos2;
3457 /* Skip forwarder blocks. This is needed to avoid forced forwarders
3458 after conditional jumps from making us to miss optimization.
3460 We don't need to worry about multiple entry or chained forwarders, as they
3461 will be optimized out. */
3462 if (e1->src->pred && !e1->src->pred->pred_next
3463 && forwarder_block_p (e1->src))
3465 if (e2->src->pred && !e2->src->pred->pred_next
3466 && forwarder_block_p (e2->src))
3469 if (e1->src == ENTRY_BLOCK_PTR || e2->src == ENTRY_BLOCK_PTR)
3471 if (e1->src == e2->src)
3474 /* Seeing more than 1 forwarder blocks would confuse us later... */
3475 if (forwarder_block_p (e1->dest)
3476 && forwarder_block_p (e1->dest->succ->dest))
3478 if (forwarder_block_p (e2->dest)
3479 && forwarder_block_p (e2->dest->succ->dest))
3481 /* ... similary as seeing dead code... */
3482 if (!e1->src->pred || !e2->src->pred)
3484 /* ...similary non-jump edges. */
3485 if (e1->flags & EDGE_COMPLEX)
3488 if (!outgoing_edges_match (e1->src, e2->src))
3490 nmatch = flow_find_cross_jump (mode, e1->src, e2->src, &newpos1, &newpos2);
3494 /* Avoid splitting if possible. */
3495 if (newpos2 == e2->src->head)
3496 redirect_to = e2->src;
3500 fprintf (rtl_dump_file, "Splitting bb %i before %i insns\n",
3501 e2->src->index, nmatch);
3502 redirect_to = split_block (e2->src, PREV_INSN (newpos2))->dest;
3506 fprintf (rtl_dump_file,
3507 "Cross jumping from bb %i to bb %i. %i insn commoized\n",
3508 e1->src->index, e2->src->index, nmatch);
3510 redirect_to->count += e1->src->count;
3511 redirect_to->frequency += e1->src->frequency;
3513 /* Recompute the frequencies and counts of outgoing edges. */
3514 for (s = redirect_to->succ; s; s = s->succ_next)
3517 basic_block d = (forwarder_block_p (s->dest) ? s->dest->succ->dest
3519 for (s2 = e1->src->succ;; s2 = s2->succ_next)
3522 (forwarder_block_p (s2->dest) ? s2->dest->succ->dest : s2->dest);
3526 s->count += s2->count;
3528 /* Take care to update possible forwarder blocks. We took care
3529 that there is no more than one in chain, so we can't run
3530 into infinite loop. */
3531 if (forwarder_block_p (s->dest))
3533 s->dest->succ->count += s2->count;
3534 s->dest->count += s2->count;
3535 s->dest->frequency += ((s->probability * s->src->frequency)
3536 / REG_BR_PROB_BASE);
3538 if (forwarder_block_p (s2->dest))
3540 s2->dest->succ->count -= s2->count;
3541 s2->dest->count -= s2->count;
3542 s2->dest->frequency -= ((s->probability * s->src->frequency)
3543 / REG_BR_PROB_BASE);
3545 if (!redirect_to->frequency && !e1->src->frequency)
3546 s->probability = (s->probability + s2->probability) / 2;
3549 ((s->probability * redirect_to->frequency +
3550 s2->probability * e1->src->frequency)
3551 / (redirect_to->frequency + e1->src->frequency));
3554 /* FIXME: enable once probabilities are fetched properly at
3557 note = find_reg_note (redirect_to->end, REG_BR_PROB, 0);
3559 XEXP (note, 0) = GEN_INT (BRANCH_EDGE (redirect_to)->probability);
3562 /* Skip possible basic block header. */
3564 if (GET_CODE (first) == CODE_LABEL)
3565 first = NEXT_INSN (first);
3566 if (GET_CODE (first) == NOTE)
3567 first = NEXT_INSN (first);
3569 last = e1->src->end;
3571 /* Now emit the jump insn. */
3572 label = block_label (redirect_to);
3573 e1->src->end = emit_jump_insn_after (gen_jump (label), e1->src->end);
3574 JUMP_LABEL (e1->src->end) = label;
3575 LABEL_NUSES (label)++;
3576 if (basic_block_for_insn)
3577 set_block_for_insn (e1->src->end, e1->src);
3579 flow_delete_insn_chain (first, last);
3581 barrier = next_nonnote_insn (e1->src->end);
3582 if (!barrier || GET_CODE (barrier) != BARRIER)
3583 emit_barrier_after (e1->src->end);
3586 while (e1->src->succ->succ_next)
3587 remove_edge (e1->src->succ);
3588 e1->src->succ->flags = 0;
3589 redirect_edge_succ (e1->src->succ, redirect_to);
3593 /* Attempt to implement cross jumping. This means moving one or more branches
3594 to BB earlier to BB predecesors commonizing some code. */
3596 try_crossjump_bb (mode, bb)
3600 edge e, e2, nexte2, nexte, fallthru;
3601 bool changed = false;
3603 /* In case basic block has single predecesor, do nothing. */
3604 if (!bb->pred || !bb->pred->pred_next)
3607 /* It is always cheapest to jump into fallthru edge. */
3608 for (fallthru = bb->pred; fallthru; fallthru = fallthru->pred_next)
3609 if (fallthru->flags & EDGE_FALLTHRU)
3612 for (e = bb->pred; e; e = nexte)
3614 nexte = e->pred_next;
3615 /* First of all prioritize the fallthru edge, as the cheapest. */
3616 if (e != fallthru && fallthru
3617 && try_crossjump_to_edge (mode, e, fallthru))
3618 changed = true, nexte = bb->pred;
3620 /* Try match in other incomming edges.
3622 Loop only over the earlier edges to avoid,as the later
3623 will be examined in the oposite direction. */
3624 for (e2 = bb->pred; e2 != e; e2 = nexte2)
3626 nexte2 = e2->pred_next;
3627 if (e2 != fallthru && try_crossjump_to_edge (mode, e, e2))
3632 /* We may've removed the fallthru edge. */
3633 for (fallthru = bb->pred; fallthru;
3634 fallthru = fallthru->pred_next)
3635 if (fallthru->flags & EDGE_FALLTHRU)
3644 /* Do simple CFG optimizations - basic block merging, simplifying of jump
3647 Return nonzero in case some optimizations matched. */
3650 try_optimize_cfg (mode)
3654 bool changed_overall = 0;
3658 /* Attempt to merge blocks as made possible by edge removal. If a block
3659 has only one successor, and the successor has only one predecessor,
3660 they may be combined. */
3667 fprintf (rtl_dump_file, "\n\ntry_optimize_cfg iteration %i\n\n",
3669 for (i = 0; i < n_basic_blocks;)
3671 basic_block c, b = BASIC_BLOCK (i);
3673 int changed_here = 0;
3675 /* Delete trivially dead basic block. */
3676 if (b->pred == NULL)
3678 c = BASIC_BLOCK (i - 1);
3680 fprintf (rtl_dump_file, "Deleting block %i.\n", b->index);
3681 flow_delete_block (b);
3685 /* The fallthru forwarder block can be deleted. */
3686 if (b->pred->pred_next == NULL
3687 && forwarder_block_p (b)
3688 && n_basic_blocks > 1
3689 && (b->pred->flags & EDGE_FALLTHRU)
3690 && (b->succ->flags & EDGE_FALLTHRU))
3693 fprintf (rtl_dump_file, "Deleting fallthru block %i.\n",
3695 c = BASIC_BLOCK (i ? i - 1 : i + 1);
3696 redirect_edge_succ (b->pred, b->succ->dest);
3697 flow_delete_block (b);
3702 /* A loop because chains of blocks might be combineable. */
3703 while ((s = b->succ) != NULL
3704 && s->succ_next == NULL
3705 && (s->flags & EDGE_EH) == 0
3706 && (c = s->dest) != EXIT_BLOCK_PTR
3707 && c->pred->pred_next == NULL
3708 /* If the jump insn has side effects,
3709 we can't kill the edge. */
3710 && (GET_CODE (b->end) != JUMP_INSN
3711 || onlyjump_p (b->end)) && merge_blocks (s, b, c, mode))
3714 if ((mode & CLEANUP_EXPENSIVE) && try_simplify_condjump (b))
3717 /* In the case basic blocks has single outgoing edge, but over by the
3718 non-trivial jump instruction, we can replace it by unconditional
3719 jump, or delete the jump completely. Use logic of
3720 redirect_edge_and_branch to do the dirty job for us.
3722 We match cases as conditional jumps jumping to the next block or
3726 && b->succ->succ_next == NULL
3727 && GET_CODE (b->end) == JUMP_INSN
3728 && b->succ->dest != EXIT_BLOCK_PTR
3729 && redirect_edge_and_branch (b->succ, b->succ->dest))
3732 if (try_forward_edges (b))
3735 if ((mode & CLEANUP_CROSSJUMP) && try_crossjump_bb (mode, b))
3738 /* Don't get confused by the index shift caused by deleting
3745 if ((mode & CLEANUP_CROSSJUMP) && try_crossjump_bb (mode, EXIT_BLOCK_PTR))
3747 #ifdef ENABLE_CHECKING
3749 verify_flow_info ();
3751 changed_overall |= changed;
3754 return changed_overall;
3757 /* The given edge should potentially be a fallthru edge. If that is in
3758 fact true, delete the jump and barriers that are in the way. */
3761 tidy_fallthru_edge (e, b, c)
3767 /* ??? In a late-running flow pass, other folks may have deleted basic
3768 blocks by nopping out blocks, leaving multiple BARRIERs between here
3769 and the target label. They ought to be chastized and fixed.
3771 We can also wind up with a sequence of undeletable labels between
3772 one block and the next.
3774 So search through a sequence of barriers, labels, and notes for
3775 the head of block C and assert that we really do fall through. */
3777 if (next_real_insn (b->end) != next_real_insn (PREV_INSN (c->head)))
3780 /* Remove what will soon cease being the jump insn from the source block.
3781 If block B consisted only of this single jump, turn it into a deleted
3784 if (GET_CODE (q) == JUMP_INSN
3786 && (any_uncondjump_p (q)
3787 || (b->succ == e && e->succ_next == NULL)))
3790 /* If this was a conditional jump, we need to also delete
3791 the insn that set cc0. */
3792 if (any_condjump_p (q) && sets_cc0_p (PREV_INSN (q)))
3799 NOTE_LINE_NUMBER (q) = NOTE_INSN_DELETED;
3800 NOTE_SOURCE_FILE (q) = 0;
3806 /* We don't want a block to end on a line-number note since that has
3807 the potential of changing the code between -g and not -g. */
3808 while (GET_CODE (q) == NOTE && NOTE_LINE_NUMBER (q) >= 0)
3815 /* Selectively unlink the sequence. */
3816 if (q != PREV_INSN (c->head))
3817 flow_delete_insn_chain (NEXT_INSN (q), PREV_INSN (c->head));
3819 e->flags |= EDGE_FALLTHRU;
3822 /* Fix up edges that now fall through, or rather should now fall through
3823 but previously required a jump around now deleted blocks. Simplify
3824 the search by only examining blocks numerically adjacent, since this
3825 is how find_basic_blocks created them. */
3828 tidy_fallthru_edges ()
3832 for (i = 1; i < n_basic_blocks; ++i)
3834 basic_block b = BASIC_BLOCK (i - 1);
3835 basic_block c = BASIC_BLOCK (i);
3838 /* We care about simple conditional or unconditional jumps with
3841 If we had a conditional branch to the next instruction when
3842 find_basic_blocks was called, then there will only be one
3843 out edge for the block which ended with the conditional
3844 branch (since we do not create duplicate edges).
3846 Furthermore, the edge will be marked as a fallthru because we
3847 merge the flags for the duplicate edges. So we do not want to
3848 check that the edge is not a FALLTHRU edge. */
3849 if ((s = b->succ) != NULL
3850 && ! (s->flags & EDGE_COMPLEX)
3851 && s->succ_next == NULL
3853 /* If the jump insn has side effects, we can't tidy the edge. */
3854 && (GET_CODE (b->end) != JUMP_INSN
3855 || onlyjump_p (b->end)))
3856 tidy_fallthru_edge (s, b, c);
3860 /* Perform data flow analysis.
3861 F is the first insn of the function; FLAGS is a set of PROP_* flags
3862 to be used in accumulating flow info. */
3865 life_analysis (f, file, flags)
3870 #ifdef ELIMINABLE_REGS
3872 static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
3875 /* Record which registers will be eliminated. We use this in
3878 CLEAR_HARD_REG_SET (elim_reg_set);
3880 #ifdef ELIMINABLE_REGS
3881 for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
3882 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
3884 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
3888 flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC);
3890 /* The post-reload life analysis have (on a global basis) the same
3891 registers live as was computed by reload itself. elimination
3892 Otherwise offsets and such may be incorrect.
3894 Reload will make some registers as live even though they do not
3897 We don't want to create new auto-incs after reload, since they
3898 are unlikely to be useful and can cause problems with shared
3900 if (reload_completed)
3901 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
3903 /* We want alias analysis information for local dead store elimination. */
3904 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
3905 init_alias_analysis ();
3907 /* Always remove no-op moves. Do this before other processing so
3908 that we don't have to keep re-scanning them. */
3909 delete_noop_moves (f);
3911 /* Some targets can emit simpler epilogues if they know that sp was
3912 not ever modified during the function. After reload, of course,
3913 we've already emitted the epilogue so there's no sense searching. */
3914 if (! reload_completed)
3915 notice_stack_pointer_modification (f);
3917 /* Allocate and zero out data structures that will record the
3918 data from lifetime analysis. */
3919 allocate_reg_life_data ();
3920 allocate_bb_life_data ();
3922 /* Find the set of registers live on function exit. */
3923 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
3925 /* "Update" life info from zero. It'd be nice to begin the
3926 relaxation with just the exit and noreturn blocks, but that set
3927 is not immediately handy. */
3929 if (flags & PROP_REG_INFO)
3930 memset (regs_ever_live, 0, sizeof (regs_ever_live));
3931 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
3934 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
3935 end_alias_analysis ();
3938 dump_flow_info (file);
3940 free_basic_block_vars (1);
3942 #ifdef ENABLE_CHECKING
3946 /* Search for any REG_LABEL notes which reference deleted labels. */
3947 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
3949 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
3951 if (inote && GET_CODE (inote) == NOTE_INSN_DELETED_LABEL)
3958 /* A subroutine of verify_wide_reg, called through for_each_rtx.
3959 Search for REGNO. If found, abort if it is not wider than word_mode. */
3962 verify_wide_reg_1 (px, pregno)
3967 unsigned int regno = *(int *) pregno;
3969 if (GET_CODE (x) == REG && REGNO (x) == regno)
3971 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
3978 /* A subroutine of verify_local_live_at_start. Search through insns
3979 between HEAD and END looking for register REGNO. */
3982 verify_wide_reg (regno, head, end)
3989 && for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no))
3993 head = NEXT_INSN (head);
3996 /* We didn't find the register at all. Something's way screwy. */
3998 fprintf (rtl_dump_file, "Aborting in verify_wide_reg; reg %d\n", regno);
3999 print_rtl_and_abort ();
4002 /* A subroutine of update_life_info. Verify that there are no untoward
4003 changes in live_at_start during a local update. */
4006 verify_local_live_at_start (new_live_at_start, bb)
4007 regset new_live_at_start;
4010 if (reload_completed)
4012 /* After reload, there are no pseudos, nor subregs of multi-word
4013 registers. The regsets should exactly match. */
4014 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
4018 fprintf (rtl_dump_file,
4019 "live_at_start mismatch in bb %d, aborting\n",
4021 debug_bitmap_file (rtl_dump_file, bb->global_live_at_start);
4022 debug_bitmap_file (rtl_dump_file, new_live_at_start);
4024 print_rtl_and_abort ();
4031 /* Find the set of changed registers. */
4032 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
4034 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
4036 /* No registers should die. */
4037 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
4040 fprintf (rtl_dump_file,
4041 "Register %d died unexpectedly in block %d\n", i,
4043 print_rtl_and_abort ();
4046 /* Verify that the now-live register is wider than word_mode. */
4047 verify_wide_reg (i, bb->head, bb->end);
4052 /* Updates life information starting with the basic blocks set in BLOCKS.
4053 If BLOCKS is null, consider it to be the universal set.
4055 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
4056 we are only expecting local modifications to basic blocks. If we find
4057 extra registers live at the beginning of a block, then we either killed
4058 useful data, or we have a broken split that wants data not provided.
4059 If we find registers removed from live_at_start, that means we have
4060 a broken peephole that is killing a register it shouldn't.
4062 ??? This is not true in one situation -- when a pre-reload splitter
4063 generates subregs of a multi-word pseudo, current life analysis will
4064 lose the kill. So we _can_ have a pseudo go live. How irritating.
4066 Including PROP_REG_INFO does not properly refresh regs_ever_live
4067 unless the caller resets it to zero. */
4070 update_life_info (blocks, extent, prop_flags)
4072 enum update_life_extent extent;
4076 regset_head tmp_head;
4079 tmp = INITIALIZE_REG_SET (tmp_head);
4081 /* For a global update, we go through the relaxation process again. */
4082 if (extent != UPDATE_LIFE_LOCAL)
4084 calculate_global_regs_live (blocks, blocks,
4085 prop_flags & PROP_SCAN_DEAD_CODE);
4087 /* If asked, remove notes from the blocks we'll update. */
4088 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
4089 count_or_remove_death_notes (blocks, 1);
4094 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
4096 basic_block bb = BASIC_BLOCK (i);
4098 COPY_REG_SET (tmp, bb->global_live_at_end);
4099 propagate_block (bb, tmp, NULL, NULL, prop_flags);
4101 if (extent == UPDATE_LIFE_LOCAL)
4102 verify_local_live_at_start (tmp, bb);
4107 for (i = n_basic_blocks - 1; i >= 0; --i)
4109 basic_block bb = BASIC_BLOCK (i);
4111 COPY_REG_SET (tmp, bb->global_live_at_end);
4112 propagate_block (bb, tmp, NULL, NULL, prop_flags);
4114 if (extent == UPDATE_LIFE_LOCAL)
4115 verify_local_live_at_start (tmp, bb);
4121 if (prop_flags & PROP_REG_INFO)
4123 /* The only pseudos that are live at the beginning of the function
4124 are those that were not set anywhere in the function. local-alloc
4125 doesn't know how to handle these correctly, so mark them as not
4126 local to any one basic block. */
4127 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
4128 FIRST_PSEUDO_REGISTER, i,
4129 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
4131 /* We have a problem with any pseudoreg that lives across the setjmp.
4132 ANSI says that if a user variable does not change in value between
4133 the setjmp and the longjmp, then the longjmp preserves it. This
4134 includes longjmp from a place where the pseudo appears dead.
4135 (In principle, the value still exists if it is in scope.)
4136 If the pseudo goes in a hard reg, some other value may occupy
4137 that hard reg where this pseudo is dead, thus clobbering the pseudo.
4138 Conclusion: such a pseudo must not go in a hard reg. */
4139 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
4140 FIRST_PSEUDO_REGISTER, i,
4142 if (regno_reg_rtx[i] != 0)
4144 REG_LIVE_LENGTH (i) = -1;
4145 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
4151 /* Free the variables allocated by find_basic_blocks.
4153 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
4156 free_basic_block_vars (keep_head_end_p)
4157 int keep_head_end_p;
4159 if (basic_block_for_insn)
4161 VARRAY_FREE (basic_block_for_insn);
4162 basic_block_for_insn = NULL;
4165 if (! keep_head_end_p)
4167 if (basic_block_info)
4170 VARRAY_FREE (basic_block_info);
4174 ENTRY_BLOCK_PTR->aux = NULL;
4175 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
4176 EXIT_BLOCK_PTR->aux = NULL;
4177 EXIT_BLOCK_PTR->global_live_at_start = NULL;
4181 /* Return nonzero if an insn consists only of SETs, each of which only sets a
4188 rtx pat = PATTERN (insn);
4190 /* Insns carrying these notes are useful later on. */
4191 if (find_reg_note (insn, REG_EQUAL, NULL_RTX))
4194 if (GET_CODE (pat) == SET && set_noop_p (pat))
4197 if (GET_CODE (pat) == PARALLEL)
4200 /* If nothing but SETs of registers to themselves,
4201 this insn can also be deleted. */
4202 for (i = 0; i < XVECLEN (pat, 0); i++)
4204 rtx tem = XVECEXP (pat, 0, i);
4206 if (GET_CODE (tem) == USE
4207 || GET_CODE (tem) == CLOBBER)
4210 if (GET_CODE (tem) != SET || ! set_noop_p (tem))
4219 /* Delete any insns that copy a register to itself. */
4222 delete_noop_moves (f)
4226 for (insn = f; insn; insn = NEXT_INSN (insn))
4228 if (GET_CODE (insn) == INSN && noop_move_p (insn))
4230 PUT_CODE (insn, NOTE);
4231 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
4232 NOTE_SOURCE_FILE (insn) = 0;
4237 /* Determine if the stack pointer is constant over the life of the function.
4238 Only useful before prologues have been emitted. */
4241 notice_stack_pointer_modification_1 (x, pat, data)
4243 rtx pat ATTRIBUTE_UNUSED;
4244 void *data ATTRIBUTE_UNUSED;
4246 if (x == stack_pointer_rtx
4247 /* The stack pointer is only modified indirectly as the result
4248 of a push until later in flow. See the comments in rtl.texi
4249 regarding Embedded Side-Effects on Addresses. */
4250 || (GET_CODE (x) == MEM
4251 && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
4252 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
4253 current_function_sp_is_unchanging = 0;
4257 notice_stack_pointer_modification (f)
4262 /* Assume that the stack pointer is unchanging if alloca hasn't
4264 current_function_sp_is_unchanging = !current_function_calls_alloca;
4265 if (! current_function_sp_is_unchanging)
4268 for (insn = f; insn; insn = NEXT_INSN (insn))
4272 /* Check if insn modifies the stack pointer. */
4273 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
4275 if (! current_function_sp_is_unchanging)
4281 /* Mark a register in SET. Hard registers in large modes get all
4282 of their component registers set as well. */
4285 mark_reg (reg, xset)
4289 regset set = (regset) xset;
4290 int regno = REGNO (reg);
4292 if (GET_MODE (reg) == BLKmode)
4295 SET_REGNO_REG_SET (set, regno);
4296 if (regno < FIRST_PSEUDO_REGISTER)
4298 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
4300 SET_REGNO_REG_SET (set, regno + n);
4304 /* Mark those regs which are needed at the end of the function as live
4305 at the end of the last basic block. */
4308 mark_regs_live_at_end (set)
4313 /* If exiting needs the right stack value, consider the stack pointer
4314 live at the end of the function. */
4315 if ((HAVE_epilogue && reload_completed)
4316 || ! EXIT_IGNORE_STACK
4317 || (! FRAME_POINTER_REQUIRED
4318 && ! current_function_calls_alloca
4319 && flag_omit_frame_pointer)
4320 || current_function_sp_is_unchanging)
4322 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
4325 /* Mark the frame pointer if needed at the end of the function. If
4326 we end up eliminating it, it will be removed from the live list
4327 of each basic block by reload. */
4329 if (! reload_completed || frame_pointer_needed)
4331 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
4332 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4333 /* If they are different, also mark the hard frame pointer as live. */
4334 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
4335 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
4339 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
4340 /* Many architectures have a GP register even without flag_pic.
4341 Assume the pic register is not in use, or will be handled by
4342 other means, if it is not fixed. */
4343 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
4344 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
4345 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
4348 /* Mark all global registers, and all registers used by the epilogue
4349 as being live at the end of the function since they may be
4350 referenced by our caller. */
4351 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
4352 if (global_regs[i] || EPILOGUE_USES (i))
4353 SET_REGNO_REG_SET (set, i);
4355 if (HAVE_epilogue && reload_completed)
4357 /* Mark all call-saved registers that we actually used. */
4358 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
4359 if (regs_ever_live[i] && ! call_used_regs[i] && ! LOCAL_REGNO (i))
4360 SET_REGNO_REG_SET (set, i);
4363 #ifdef EH_RETURN_DATA_REGNO
4364 /* Mark the registers that will contain data for the handler. */
4365 if (reload_completed && current_function_calls_eh_return)
4368 unsigned regno = EH_RETURN_DATA_REGNO(i);
4369 if (regno == INVALID_REGNUM)
4371 SET_REGNO_REG_SET (set, regno);
4374 #ifdef EH_RETURN_STACKADJ_RTX
4375 if ((! HAVE_epilogue || ! reload_completed)
4376 && current_function_calls_eh_return)
4378 rtx tmp = EH_RETURN_STACKADJ_RTX;
4379 if (tmp && REG_P (tmp))
4380 mark_reg (tmp, set);
4383 #ifdef EH_RETURN_HANDLER_RTX
4384 if ((! HAVE_epilogue || ! reload_completed)
4385 && current_function_calls_eh_return)
4387 rtx tmp = EH_RETURN_HANDLER_RTX;
4388 if (tmp && REG_P (tmp))
4389 mark_reg (tmp, set);
4393 /* Mark function return value. */
4394 diddle_return_value (mark_reg, set);
4397 /* Callback function for for_each_successor_phi. DATA is a regset.
4398 Sets the SRC_REGNO, the regno of the phi alternative for phi node
4399 INSN, in the regset. */
4402 set_phi_alternative_reg (insn, dest_regno, src_regno, data)
4403 rtx insn ATTRIBUTE_UNUSED;
4404 int dest_regno ATTRIBUTE_UNUSED;
4408 regset live = (regset) data;
4409 SET_REGNO_REG_SET (live, src_regno);
4413 /* Propagate global life info around the graph of basic blocks. Begin
4414 considering blocks with their corresponding bit set in BLOCKS_IN.
4415 If BLOCKS_IN is null, consider it the universal set.
4417 BLOCKS_OUT is set for every block that was changed. */
4420 calculate_global_regs_live (blocks_in, blocks_out, flags)
4421 sbitmap blocks_in, blocks_out;
4424 basic_block *queue, *qhead, *qtail, *qend;
4425 regset tmp, new_live_at_end, call_used;
4426 regset_head tmp_head, call_used_head;
4427 regset_head new_live_at_end_head;
4430 tmp = INITIALIZE_REG_SET (tmp_head);
4431 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
4432 call_used = INITIALIZE_REG_SET (call_used_head);
4434 /* Inconveniently, this is only redily available in hard reg set form. */
4435 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
4436 if (call_used_regs[i])
4437 SET_REGNO_REG_SET (call_used, i);
4439 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
4440 because the `head == tail' style test for an empty queue doesn't
4441 work with a full queue. */
4442 queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
4444 qhead = qend = queue + n_basic_blocks + 2;
4446 /* Queue the blocks set in the initial mask. Do this in reverse block
4447 number order so that we are more likely for the first round to do
4448 useful work. We use AUX non-null to flag that the block is queued. */
4451 /* Clear out the garbage that might be hanging out in bb->aux. */
4452 for (i = n_basic_blocks - 1; i >= 0; --i)
4453 BASIC_BLOCK (i)->aux = NULL;
4455 EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
4457 basic_block bb = BASIC_BLOCK (i);
4464 for (i = 0; i < n_basic_blocks; ++i)
4466 basic_block bb = BASIC_BLOCK (i);
4473 sbitmap_zero (blocks_out);
4475 /* We work through the queue until there are no more blocks. What
4476 is live at the end of this block is precisely the union of what
4477 is live at the beginning of all its successors. So, we set its
4478 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
4479 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
4480 this block by walking through the instructions in this block in
4481 reverse order and updating as we go. If that changed
4482 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
4483 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
4485 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
4486 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
4487 must either be live at the end of the block, or used within the
4488 block. In the latter case, it will certainly never disappear
4489 from GLOBAL_LIVE_AT_START. In the former case, the register
4490 could go away only if it disappeared from GLOBAL_LIVE_AT_START
4491 for one of the successor blocks. By induction, that cannot
4493 while (qhead != qtail)
4495 int rescan, changed;
4504 /* Begin by propagating live_at_start from the successor blocks. */
4505 CLEAR_REG_SET (new_live_at_end);
4506 for (e = bb->succ; e; e = e->succ_next)
4508 basic_block sb = e->dest;
4510 /* Call-clobbered registers die across exception and call edges. */
4511 /* ??? Abnormal call edges ignored for the moment, as this gets
4512 confused by sibling call edges, which crashes reg-stack. */
4513 if (e->flags & EDGE_EH)
4515 bitmap_operation (tmp, sb->global_live_at_start,
4516 call_used, BITMAP_AND_COMPL);
4517 IOR_REG_SET (new_live_at_end, tmp);
4520 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
4523 /* The all-important stack pointer must always be live. */
4524 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
4526 /* Before reload, there are a few registers that must be forced
4527 live everywhere -- which might not already be the case for
4528 blocks within infinite loops. */
4529 if (! reload_completed)
4531 /* Any reference to any pseudo before reload is a potential
4532 reference of the frame pointer. */
4533 SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
4535 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4536 /* Pseudos with argument area equivalences may require
4537 reloading via the argument pointer. */
4538 if (fixed_regs[ARG_POINTER_REGNUM])
4539 SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
4542 /* Any constant, or pseudo with constant equivalences, may
4543 require reloading from memory using the pic register. */
4544 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
4545 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
4546 SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
4549 /* Regs used in phi nodes are not included in
4550 global_live_at_start, since they are live only along a
4551 particular edge. Set those regs that are live because of a
4552 phi node alternative corresponding to this particular block. */
4554 for_each_successor_phi (bb, &set_phi_alternative_reg,
4557 if (bb == ENTRY_BLOCK_PTR)
4559 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
4563 /* On our first pass through this block, we'll go ahead and continue.
4564 Recognize first pass by local_set NULL. On subsequent passes, we
4565 get to skip out early if live_at_end wouldn't have changed. */
4567 if (bb->local_set == NULL)
4569 bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
4570 bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
4575 /* If any bits were removed from live_at_end, we'll have to
4576 rescan the block. This wouldn't be necessary if we had
4577 precalculated local_live, however with PROP_SCAN_DEAD_CODE
4578 local_live is really dependent on live_at_end. */
4579 CLEAR_REG_SET (tmp);
4580 rescan = bitmap_operation (tmp, bb->global_live_at_end,
4581 new_live_at_end, BITMAP_AND_COMPL);
4585 /* If any of the registers in the new live_at_end set are
4586 conditionally set in this basic block, we must rescan.
4587 This is because conditional lifetimes at the end of the
4588 block do not just take the live_at_end set into account,
4589 but also the liveness at the start of each successor
4590 block. We can miss changes in those sets if we only
4591 compare the new live_at_end against the previous one. */
4592 CLEAR_REG_SET (tmp);
4593 rescan = bitmap_operation (tmp, new_live_at_end,
4594 bb->cond_local_set, BITMAP_AND);
4599 /* Find the set of changed bits. Take this opportunity
4600 to notice that this set is empty and early out. */
4601 CLEAR_REG_SET (tmp);
4602 changed = bitmap_operation (tmp, bb->global_live_at_end,
4603 new_live_at_end, BITMAP_XOR);
4607 /* If any of the changed bits overlap with local_set,
4608 we'll have to rescan the block. Detect overlap by
4609 the AND with ~local_set turning off bits. */
4610 rescan = bitmap_operation (tmp, tmp, bb->local_set,
4615 /* Let our caller know that BB changed enough to require its
4616 death notes updated. */
4618 SET_BIT (blocks_out, bb->index);
4622 /* Add to live_at_start the set of all registers in
4623 new_live_at_end that aren't in the old live_at_end. */
4625 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
4627 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
4629 changed = bitmap_operation (bb->global_live_at_start,
4630 bb->global_live_at_start,
4637 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
4639 /* Rescan the block insn by insn to turn (a copy of) live_at_end
4640 into live_at_start. */
4641 propagate_block (bb, new_live_at_end, bb->local_set,
4642 bb->cond_local_set, flags);
4644 /* If live_at start didn't change, no need to go farther. */
4645 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
4648 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
4651 /* Queue all predecessors of BB so that we may re-examine
4652 their live_at_end. */
4653 for (e = bb->pred; e; e = e->pred_next)
4655 basic_block pb = e->src;
4656 if (pb->aux == NULL)
4667 FREE_REG_SET (new_live_at_end);
4668 FREE_REG_SET (call_used);
4672 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
4674 basic_block bb = BASIC_BLOCK (i);
4675 FREE_REG_SET (bb->local_set);
4676 FREE_REG_SET (bb->cond_local_set);
4681 for (i = n_basic_blocks - 1; i >= 0; --i)
4683 basic_block bb = BASIC_BLOCK (i);
4684 FREE_REG_SET (bb->local_set);
4685 FREE_REG_SET (bb->cond_local_set);
4692 /* Subroutines of life analysis. */
4694 /* Allocate the permanent data structures that represent the results
4695 of life analysis. Not static since used also for stupid life analysis. */
4698 allocate_bb_life_data ()
4702 for (i = 0; i < n_basic_blocks; i++)
4704 basic_block bb = BASIC_BLOCK (i);
4706 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
4707 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
4710 ENTRY_BLOCK_PTR->global_live_at_end
4711 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
4712 EXIT_BLOCK_PTR->global_live_at_start
4713 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
4715 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
4719 allocate_reg_life_data ()
4723 max_regno = max_reg_num ();
4725 /* Recalculate the register space, in case it has grown. Old style
4726 vector oriented regsets would set regset_{size,bytes} here also. */
4727 allocate_reg_info (max_regno, FALSE, FALSE);
4729 /* Reset all the data we'll collect in propagate_block and its
4731 for (i = 0; i < max_regno; i++)
4735 REG_N_DEATHS (i) = 0;
4736 REG_N_CALLS_CROSSED (i) = 0;
4737 REG_LIVE_LENGTH (i) = 0;
4738 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
4742 /* Delete dead instructions for propagate_block. */
4745 propagate_block_delete_insn (bb, insn)
4749 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
4751 /* If the insn referred to a label, and that label was attached to
4752 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
4753 pretty much mandatory to delete it, because the ADDR_VEC may be
4754 referencing labels that no longer exist.
4756 INSN may reference a deleted label, particularly when a jump
4757 table has been optimized into a direct jump. There's no
4758 real good way to fix up the reference to the deleted label
4759 when the label is deleted, so we just allow it here.
4761 After dead code elimination is complete, we do search for
4762 any REG_LABEL notes which reference deleted labels as a
4765 if (inote && GET_CODE (inote) == CODE_LABEL)
4767 rtx label = XEXP (inote, 0);
4770 /* The label may be forced if it has been put in the constant
4771 pool. If that is the only use we must discard the table
4772 jump following it, but not the label itself. */
4773 if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
4774 && (next = next_nonnote_insn (label)) != NULL
4775 && GET_CODE (next) == JUMP_INSN
4776 && (GET_CODE (PATTERN (next)) == ADDR_VEC
4777 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
4779 rtx pat = PATTERN (next);
4780 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
4781 int len = XVECLEN (pat, diff_vec_p);
4784 for (i = 0; i < len; i++)
4785 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
4787 flow_delete_insn (next);
4791 if (bb->end == insn)
4792 bb->end = PREV_INSN (insn);
4793 flow_delete_insn (insn);
4796 /* Delete dead libcalls for propagate_block. Return the insn
4797 before the libcall. */
4800 propagate_block_delete_libcall (bb, insn, note)
4804 rtx first = XEXP (note, 0);
4805 rtx before = PREV_INSN (first);
4807 if (insn == bb->end)
4810 flow_delete_insn_chain (first, insn);
4814 /* Update the life-status of regs for one insn. Return the previous insn. */
4817 propagate_one_insn (pbi, insn)
4818 struct propagate_block_info *pbi;
4821 rtx prev = PREV_INSN (insn);
4822 int flags = pbi->flags;
4823 int insn_is_dead = 0;
4824 int libcall_is_dead = 0;
4828 if (! INSN_P (insn))
4831 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
4832 if (flags & PROP_SCAN_DEAD_CODE)
4834 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
4835 libcall_is_dead = (insn_is_dead && note != 0
4836 && libcall_dead_p (pbi, note, insn));
4839 /* If an instruction consists of just dead store(s) on final pass,
4841 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
4843 /* If we're trying to delete a prologue or epilogue instruction
4844 that isn't flagged as possibly being dead, something is wrong.
4845 But if we are keeping the stack pointer depressed, we might well
4846 be deleting insns that are used to compute the amount to update
4847 it by, so they are fine. */
4848 if (reload_completed
4849 && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
4850 && (TYPE_RETURNS_STACK_DEPRESSED
4851 (TREE_TYPE (current_function_decl))))
4852 && (((HAVE_epilogue || HAVE_prologue)
4853 && prologue_epilogue_contains (insn))
4854 || (HAVE_sibcall_epilogue
4855 && sibcall_epilogue_contains (insn)))
4856 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
4859 /* Record sets. Do this even for dead instructions, since they
4860 would have killed the values if they hadn't been deleted. */
4861 mark_set_regs (pbi, PATTERN (insn), insn);
4863 /* CC0 is now known to be dead. Either this insn used it,
4864 in which case it doesn't anymore, or clobbered it,
4865 so the next insn can't use it. */
4868 if (libcall_is_dead)
4869 prev = propagate_block_delete_libcall (pbi->bb, insn, note);
4871 propagate_block_delete_insn (pbi->bb, insn);
4876 /* See if this is an increment or decrement that can be merged into
4877 a following memory address. */
4880 register rtx x = single_set (insn);
4882 /* Does this instruction increment or decrement a register? */
4883 if ((flags & PROP_AUTOINC)
4885 && GET_CODE (SET_DEST (x)) == REG
4886 && (GET_CODE (SET_SRC (x)) == PLUS
4887 || GET_CODE (SET_SRC (x)) == MINUS)
4888 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
4889 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
4890 /* Ok, look for a following memory ref we can combine with.
4891 If one is found, change the memory ref to a PRE_INC
4892 or PRE_DEC, cancel this insn, and return 1.
4893 Return 0 if nothing has been done. */
4894 && try_pre_increment_1 (pbi, insn))
4897 #endif /* AUTO_INC_DEC */
4899 CLEAR_REG_SET (pbi->new_set);
4901 /* If this is not the final pass, and this insn is copying the value of
4902 a library call and it's dead, don't scan the insns that perform the
4903 library call, so that the call's arguments are not marked live. */
4904 if (libcall_is_dead)
4906 /* Record the death of the dest reg. */
4907 mark_set_regs (pbi, PATTERN (insn), insn);
4909 insn = XEXP (note, 0);
4910 return PREV_INSN (insn);
4912 else if (GET_CODE (PATTERN (insn)) == SET
4913 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
4914 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
4915 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
4916 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
4917 /* We have an insn to pop a constant amount off the stack.
4918 (Such insns use PLUS regardless of the direction of the stack,
4919 and any insn to adjust the stack by a constant is always a pop.)
4920 These insns, if not dead stores, have no effect on life. */
4924 /* Any regs live at the time of a call instruction must not go
4925 in a register clobbered by calls. Find all regs now live and
4926 record this for them. */
4928 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
4929 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
4930 { REG_N_CALLS_CROSSED (i)++; });
4932 /* Record sets. Do this even for dead instructions, since they
4933 would have killed the values if they hadn't been deleted. */
4934 mark_set_regs (pbi, PATTERN (insn), insn);
4936 if (GET_CODE (insn) == CALL_INSN)
4942 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
4943 cond = COND_EXEC_TEST (PATTERN (insn));
4945 /* Non-constant calls clobber memory. */
4946 if (! CONST_CALL_P (insn))
4948 free_EXPR_LIST_list (&pbi->mem_set_list);
4949 pbi->mem_set_list_len = 0;
4952 /* There may be extra registers to be clobbered. */
4953 for (note = CALL_INSN_FUNCTION_USAGE (insn);
4955 note = XEXP (note, 1))
4956 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
4957 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
4958 cond, insn, pbi->flags);
4960 /* Calls change all call-used and global registers. */
4961 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
4962 if (call_used_regs[i] && ! global_regs[i]
4965 /* We do not want REG_UNUSED notes for these registers. */
4966 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
4968 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
4972 /* If an insn doesn't use CC0, it becomes dead since we assume
4973 that every insn clobbers it. So show it dead here;
4974 mark_used_regs will set it live if it is referenced. */
4979 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
4981 /* Sometimes we may have inserted something before INSN (such as a move)
4982 when we make an auto-inc. So ensure we will scan those insns. */
4984 prev = PREV_INSN (insn);
4987 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
4993 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
4994 cond = COND_EXEC_TEST (PATTERN (insn));
4996 /* Calls use their arguments. */
4997 for (note = CALL_INSN_FUNCTION_USAGE (insn);
4999 note = XEXP (note, 1))
5000 if (GET_CODE (XEXP (note, 0)) == USE)
5001 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
5004 /* The stack ptr is used (honorarily) by a CALL insn. */
5005 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
5007 /* Calls may also reference any of the global registers,
5008 so they are made live. */
5009 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
5011 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
5016 /* On final pass, update counts of how many insns in which each reg
5018 if (flags & PROP_REG_INFO)
5019 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
5020 { REG_LIVE_LENGTH (i)++; });
5025 /* Initialize a propagate_block_info struct for public consumption.
5026 Note that the structure itself is opaque to this file, but that
5027 the user can use the regsets provided here. */
5029 struct propagate_block_info *
5030 init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
5032 regset live, local_set, cond_local_set;
5035 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
5038 pbi->reg_live = live;
5039 pbi->mem_set_list = NULL_RTX;
5040 pbi->mem_set_list_len = 0;
5041 pbi->local_set = local_set;
5042 pbi->cond_local_set = cond_local_set;
5046 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
5047 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
5049 pbi->reg_next_use = NULL;
5051 pbi->new_set = BITMAP_XMALLOC ();
5053 #ifdef HAVE_conditional_execution
5054 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
5055 free_reg_cond_life_info);
5056 pbi->reg_cond_reg = BITMAP_XMALLOC ();
5058 /* If this block ends in a conditional branch, for each register live
5059 from one side of the branch and not the other, record the register
5060 as conditionally dead. */
5061 if (GET_CODE (bb->end) == JUMP_INSN
5062 && any_condjump_p (bb->end))
5064 regset_head diff_head;
5065 regset diff = INITIALIZE_REG_SET (diff_head);
5066 basic_block bb_true, bb_false;
5067 rtx cond_true, cond_false, set_src;
5070 /* Identify the successor blocks. */
5071 bb_true = bb->succ->dest;
5072 if (bb->succ->succ_next != NULL)
5074 bb_false = bb->succ->succ_next->dest;
5076 if (bb->succ->flags & EDGE_FALLTHRU)
5078 basic_block t = bb_false;
5082 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
5087 /* This can happen with a conditional jump to the next insn. */
5088 if (JUMP_LABEL (bb->end) != bb_true->head)
5091 /* Simplest way to do nothing. */
5095 /* Extract the condition from the branch. */
5096 set_src = SET_SRC (pc_set (bb->end));
5097 cond_true = XEXP (set_src, 0);
5098 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
5099 GET_MODE (cond_true), XEXP (cond_true, 0),
5100 XEXP (cond_true, 1));
5101 if (GET_CODE (XEXP (set_src, 1)) == PC)
5104 cond_false = cond_true;
5108 /* Compute which register lead different lives in the successors. */
5109 if (bitmap_operation (diff, bb_true->global_live_at_start,
5110 bb_false->global_live_at_start, BITMAP_XOR))
5112 rtx reg = XEXP (cond_true, 0);
5114 if (GET_CODE (reg) == SUBREG)
5115 reg = SUBREG_REG (reg);
5117 if (GET_CODE (reg) != REG)
5120 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
5122 /* For each such register, mark it conditionally dead. */
5123 EXECUTE_IF_SET_IN_REG_SET
5126 struct reg_cond_life_info *rcli;
5129 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
5131 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
5135 rcli->condition = cond;
5136 rcli->stores = const0_rtx;
5137 rcli->orig_condition = cond;
5139 splay_tree_insert (pbi->reg_cond_dead, i,
5140 (splay_tree_value) rcli);
5144 FREE_REG_SET (diff);
5148 /* If this block has no successors, any stores to the frame that aren't
5149 used later in the block are dead. So make a pass over the block
5150 recording any such that are made and show them dead at the end. We do
5151 a very conservative and simple job here. */
5153 && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
5154 && (TYPE_RETURNS_STACK_DEPRESSED
5155 (TREE_TYPE (current_function_decl))))
5156 && (flags & PROP_SCAN_DEAD_CODE)
5157 && (bb->succ == NULL
5158 || (bb->succ->succ_next == NULL
5159 && bb->succ->dest == EXIT_BLOCK_PTR
5160 && ! current_function_calls_eh_return)))
5163 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
5164 if (GET_CODE (insn) == INSN
5165 && (set = single_set (insn))
5166 && GET_CODE (SET_DEST (set)) == MEM)
5168 rtx mem = SET_DEST (set);
5169 rtx canon_mem = canon_rtx (mem);
5171 /* This optimization is performed by faking a store to the
5172 memory at the end of the block. This doesn't work for
5173 unchanging memories because multiple stores to unchanging
5174 memory is illegal and alias analysis doesn't consider it. */
5175 if (RTX_UNCHANGING_P (canon_mem))
5178 if (XEXP (canon_mem, 0) == frame_pointer_rtx
5179 || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
5180 && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
5181 && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
5184 /* Store a copy of mem, otherwise the address may be scrogged
5185 by find_auto_inc. This matters because insn_dead_p uses
5186 an rtx_equal_p check to determine if two addresses are
5187 the same. This works before find_auto_inc, but fails
5188 after find_auto_inc, causing discrepencies between the
5189 set of live registers calculated during the
5190 calculate_global_regs_live phase and what actually exists
5191 after flow completes, leading to aborts. */
5192 if (flags & PROP_AUTOINC)
5193 mem = shallow_copy_rtx (mem);
5195 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
5196 if (++pbi->mem_set_list_len >= MAX_MEM_SET_LIST_LEN)
5205 /* Release a propagate_block_info struct. */
5208 free_propagate_block_info (pbi)
5209 struct propagate_block_info *pbi;
5211 free_EXPR_LIST_list (&pbi->mem_set_list);
5213 BITMAP_XFREE (pbi->new_set);
5215 #ifdef HAVE_conditional_execution
5216 splay_tree_delete (pbi->reg_cond_dead);
5217 BITMAP_XFREE (pbi->reg_cond_reg);
5220 if (pbi->reg_next_use)
5221 free (pbi->reg_next_use);
5226 /* Compute the registers live at the beginning of a basic block BB from
5227 those live at the end.
5229 When called, REG_LIVE contains those live at the end. On return, it
5230 contains those live at the beginning.
5232 LOCAL_SET, if non-null, will be set with all registers killed
5233 unconditionally by this basic block.
5234 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
5235 killed conditionally by this basic block. If there is any unconditional
5236 set of a register, then the corresponding bit will be set in LOCAL_SET
5237 and cleared in COND_LOCAL_SET.
5238 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
5239 case, the resulting set will be equal to the union of the two sets that
5240 would otherwise be computed. */
5243 propagate_block (bb, live, local_set, cond_local_set, flags)
5247 regset cond_local_set;
5250 struct propagate_block_info *pbi;
5253 pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
5255 if (flags & PROP_REG_INFO)
5259 /* Process the regs live at the end of the block.
5260 Mark them as not local to any one basic block. */
5261 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
5262 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
5265 /* Scan the block an insn at a time from end to beginning. */
5267 for (insn = bb->end;; insn = prev)
5269 /* If this is a call to `setjmp' et al, warn if any
5270 non-volatile datum is live. */
5271 if ((flags & PROP_REG_INFO)
5272 && GET_CODE (insn) == NOTE
5273 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
5274 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
5276 prev = propagate_one_insn (pbi, insn);
5278 if (insn == bb->head)
5282 free_propagate_block_info (pbi);
5285 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
5286 (SET expressions whose destinations are registers dead after the insn).
5287 NEEDED is the regset that says which regs are alive after the insn.
5289 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
5291 If X is the entire body of an insn, NOTES contains the reg notes
5292 pertaining to the insn. */
5295 insn_dead_p (pbi, x, call_ok, notes)
5296 struct propagate_block_info *pbi;
5299 rtx notes ATTRIBUTE_UNUSED;
5301 enum rtx_code code = GET_CODE (x);
5304 /* If flow is invoked after reload, we must take existing AUTO_INC
5305 expresions into account. */
5306 if (reload_completed)
5308 for (; notes; notes = XEXP (notes, 1))
5310 if (REG_NOTE_KIND (notes) == REG_INC)
5312 int regno = REGNO (XEXP (notes, 0));
5314 /* Don't delete insns to set global regs. */
5315 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
5316 || REGNO_REG_SET_P (pbi->reg_live, regno))
5323 /* If setting something that's a reg or part of one,
5324 see if that register's altered value will be live. */
5328 rtx r = SET_DEST (x);
5331 if (GET_CODE (r) == CC0)
5332 return ! pbi->cc0_live;
5335 /* A SET that is a subroutine call cannot be dead. */
5336 if (GET_CODE (SET_SRC (x)) == CALL)
5342 /* Don't eliminate loads from volatile memory or volatile asms. */
5343 else if (volatile_refs_p (SET_SRC (x)))
5346 if (GET_CODE (r) == MEM)
5350 if (MEM_VOLATILE_P (r))
5353 /* Walk the set of memory locations we are currently tracking
5354 and see if one is an identical match to this memory location.
5355 If so, this memory write is dead (remember, we're walking
5356 backwards from the end of the block to the start). Since
5357 rtx_equal_p does not check the alias set or flags, we also
5358 must have the potential for them to conflict (anti_dependence). */
5359 for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
5360 if (anti_dependence (r, XEXP (temp, 0)))
5362 rtx mem = XEXP (temp, 0);
5364 if (rtx_equal_p (mem, r))
5367 /* Check if memory reference matches an auto increment. Only
5368 post increment/decrement or modify are valid. */
5369 if (GET_MODE (mem) == GET_MODE (r)
5370 && (GET_CODE (XEXP (mem, 0)) == POST_DEC
5371 || GET_CODE (XEXP (mem, 0)) == POST_INC
5372 || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
5373 && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
5374 && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
5381 while (GET_CODE (r) == SUBREG
5382 || GET_CODE (r) == STRICT_LOW_PART
5383 || GET_CODE (r) == ZERO_EXTRACT)
5386 if (GET_CODE (r) == REG)
5388 int regno = REGNO (r);
5391 if (REGNO_REG_SET_P (pbi->reg_live, regno))
5394 /* If this is a hard register, verify that subsequent
5395 words are not needed. */
5396 if (regno < FIRST_PSEUDO_REGISTER)
5398 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
5401 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
5405 /* Don't delete insns to set global regs. */
5406 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
5409 /* Make sure insns to set the stack pointer aren't deleted. */
5410 if (regno == STACK_POINTER_REGNUM)
5413 /* ??? These bits might be redundant with the force live bits
5414 in calculate_global_regs_live. We would delete from
5415 sequential sets; whether this actually affects real code
5416 for anything but the stack pointer I don't know. */
5417 /* Make sure insns to set the frame pointer aren't deleted. */
5418 if (regno == FRAME_POINTER_REGNUM
5419 && (! reload_completed || frame_pointer_needed))
5421 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
5422 if (regno == HARD_FRAME_POINTER_REGNUM
5423 && (! reload_completed || frame_pointer_needed))
5427 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
5428 /* Make sure insns to set arg pointer are never deleted
5429 (if the arg pointer isn't fixed, there will be a USE
5430 for it, so we can treat it normally). */
5431 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
5435 /* Otherwise, the set is dead. */
5441 /* If performing several activities, insn is dead if each activity
5442 is individually dead. Also, CLOBBERs and USEs can be ignored; a
5443 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
5445 else if (code == PARALLEL)
5447 int i = XVECLEN (x, 0);
5449 for (i--; i >= 0; i--)
5450 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
5451 && GET_CODE (XVECEXP (x, 0, i)) != USE
5452 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
5458 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
5459 is not necessarily true for hard registers. */
5460 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
5461 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
5462 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
5465 /* We do not check other CLOBBER or USE here. An insn consisting of just
5466 a CLOBBER or just a USE should not be deleted. */
5470 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
5471 return 1 if the entire library call is dead.
5472 This is true if INSN copies a register (hard or pseudo)
5473 and if the hard return reg of the call insn is dead.
5474 (The caller should have tested the destination of the SET inside
5475 INSN already for death.)
5477 If this insn doesn't just copy a register, then we don't
5478 have an ordinary libcall. In that case, cse could not have
5479 managed to substitute the source for the dest later on,
5480 so we can assume the libcall is dead.
5482 PBI is the block info giving pseudoregs live before this insn.
5483 NOTE is the REG_RETVAL note of the insn. */
5486 libcall_dead_p (pbi, note, insn)
5487 struct propagate_block_info *pbi;
5491 rtx x = single_set (insn);
5495 register rtx r = SET_SRC (x);
5496 if (GET_CODE (r) == REG)
5498 rtx call = XEXP (note, 0);
5502 /* Find the call insn. */
5503 while (call != insn && GET_CODE (call) != CALL_INSN)
5504 call = NEXT_INSN (call);
5506 /* If there is none, do nothing special,
5507 since ordinary death handling can understand these insns. */
5511 /* See if the hard reg holding the value is dead.
5512 If this is a PARALLEL, find the call within it. */
5513 call_pat = PATTERN (call);
5514 if (GET_CODE (call_pat) == PARALLEL)
5516 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
5517 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
5518 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
5521 /* This may be a library call that is returning a value
5522 via invisible pointer. Do nothing special, since
5523 ordinary death handling can understand these insns. */
5527 call_pat = XVECEXP (call_pat, 0, i);
5530 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
5536 /* Return 1 if register REGNO was used before it was set, i.e. if it is
5537 live at function entry. Don't count global register variables, variables
5538 in registers that can be used for function arg passing, or variables in
5539 fixed hard registers. */
5542 regno_uninitialized (regno)
5545 if (n_basic_blocks == 0
5546 || (regno < FIRST_PSEUDO_REGISTER
5547 && (global_regs[regno]
5548 || fixed_regs[regno]
5549 || FUNCTION_ARG_REGNO_P (regno))))
5552 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
5555 /* 1 if register REGNO was alive at a place where `setjmp' was called
5556 and was set more than once or is an argument.
5557 Such regs may be clobbered by `longjmp'. */
5560 regno_clobbered_at_setjmp (regno)
5563 if (n_basic_blocks == 0)
5566 return ((REG_N_SETS (regno) > 1
5567 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
5568 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
5571 /* INSN references memory, possibly using autoincrement addressing modes.
5572 Find any entries on the mem_set_list that need to be invalidated due
5573 to an address change. */
5576 invalidate_mems_from_autoinc (pbi, insn)
5577 struct propagate_block_info *pbi;
5580 rtx note = REG_NOTES (insn);
5581 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
5583 if (REG_NOTE_KIND (note) == REG_INC)
5585 rtx temp = pbi->mem_set_list;
5586 rtx prev = NULL_RTX;
5591 next = XEXP (temp, 1);
5592 if (reg_overlap_mentioned_p (XEXP (note, 0), XEXP (temp, 0)))
5594 /* Splice temp out of list. */
5596 XEXP (prev, 1) = next;
5598 pbi->mem_set_list = next;
5599 free_EXPR_LIST_node (temp);
5600 pbi->mem_set_list_len--;
5610 /* EXP is either a MEM or a REG. Remove any dependant entries
5611 from pbi->mem_set_list. */
5614 invalidate_mems_from_set (pbi, exp)
5615 struct propagate_block_info *pbi;
5618 rtx temp = pbi->mem_set_list;
5619 rtx prev = NULL_RTX;
5624 next = XEXP (temp, 1);
5625 if ((GET_CODE (exp) == MEM
5626 && output_dependence (XEXP (temp, 0), exp))
5627 || (GET_CODE (exp) == REG
5628 && reg_overlap_mentioned_p (exp, XEXP (temp, 0))))
5630 /* Splice this entry out of the list. */
5632 XEXP (prev, 1) = next;
5634 pbi->mem_set_list = next;
5635 free_EXPR_LIST_node (temp);
5636 pbi->mem_set_list_len--;
5644 /* Process the registers that are set within X. Their bits are set to
5645 1 in the regset DEAD, because they are dead prior to this insn.
5647 If INSN is nonzero, it is the insn being processed.
5649 FLAGS is the set of operations to perform. */
5652 mark_set_regs (pbi, x, insn)
5653 struct propagate_block_info *pbi;
5656 rtx cond = NULL_RTX;
5661 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
5663 if (REG_NOTE_KIND (link) == REG_INC)
5664 mark_set_1 (pbi, SET, XEXP (link, 0),
5665 (GET_CODE (x) == COND_EXEC
5666 ? COND_EXEC_TEST (x) : NULL_RTX),
5670 switch (code = GET_CODE (x))
5674 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
5678 cond = COND_EXEC_TEST (x);
5679 x = COND_EXEC_CODE (x);
5685 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
5687 rtx sub = XVECEXP (x, 0, i);
5688 switch (code = GET_CODE (sub))
5691 if (cond != NULL_RTX)
5694 cond = COND_EXEC_TEST (sub);
5695 sub = COND_EXEC_CODE (sub);
5696 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
5702 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
5717 /* Process a single set, which appears in INSN. REG (which may not
5718 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
5719 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
5720 If the set is conditional (because it appear in a COND_EXEC), COND
5721 will be the condition. */
5724 mark_set_1 (pbi, code, reg, cond, insn, flags)
5725 struct propagate_block_info *pbi;
5727 rtx reg, cond, insn;
5730 int regno_first = -1, regno_last = -1;
5731 unsigned long not_dead = 0;
5734 /* Modifying just one hardware register of a multi-reg value or just a
5735 byte field of a register does not mean the value from before this insn
5736 is now dead. Of course, if it was dead after it's unused now. */
5738 switch (GET_CODE (reg))
5741 /* Some targets place small structures in registers for return values of
5742 functions. We have to detect this case specially here to get correct
5743 flow information. */
5744 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
5745 if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
5746 mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
5752 case STRICT_LOW_PART:
5753 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
5755 reg = XEXP (reg, 0);
5756 while (GET_CODE (reg) == SUBREG
5757 || GET_CODE (reg) == ZERO_EXTRACT
5758 || GET_CODE (reg) == SIGN_EXTRACT
5759 || GET_CODE (reg) == STRICT_LOW_PART);
5760 if (GET_CODE (reg) == MEM)
5762 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
5766 regno_last = regno_first = REGNO (reg);
5767 if (regno_first < FIRST_PSEUDO_REGISTER)
5768 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
5772 if (GET_CODE (SUBREG_REG (reg)) == REG)
5774 enum machine_mode outer_mode = GET_MODE (reg);
5775 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
5777 /* Identify the range of registers affected. This is moderately
5778 tricky for hard registers. See alter_subreg. */
5780 regno_last = regno_first = REGNO (SUBREG_REG (reg));
5781 if (regno_first < FIRST_PSEUDO_REGISTER)
5783 regno_first += subreg_regno_offset (regno_first, inner_mode,
5786 regno_last = (regno_first
5787 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
5789 /* Since we've just adjusted the register number ranges, make
5790 sure REG matches. Otherwise some_was_live will be clear
5791 when it shouldn't have been, and we'll create incorrect
5792 REG_UNUSED notes. */
5793 reg = gen_rtx_REG (outer_mode, regno_first);
5797 /* If the number of words in the subreg is less than the number
5798 of words in the full register, we have a well-defined partial
5799 set. Otherwise the high bits are undefined.
5801 This is only really applicable to pseudos, since we just took
5802 care of multi-word hard registers. */
5803 if (((GET_MODE_SIZE (outer_mode)
5804 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
5805 < ((GET_MODE_SIZE (inner_mode)
5806 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
5807 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
5810 reg = SUBREG_REG (reg);
5814 reg = SUBREG_REG (reg);
5821 /* If this set is a MEM, then it kills any aliased writes.
5822 If this set is a REG, then it kills any MEMs which use the reg. */
5823 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
5825 if (GET_CODE (reg) == MEM || GET_CODE (reg) == REG)
5826 invalidate_mems_from_set (pbi, reg);
5828 /* If the memory reference had embedded side effects (autoincrement
5829 address modes. Then we may need to kill some entries on the
5831 if (insn && GET_CODE (reg) == MEM)
5832 invalidate_mems_from_autoinc (pbi, insn);
5834 if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN
5835 && GET_CODE (reg) == MEM && ! side_effects_p (reg)
5836 /* ??? With more effort we could track conditional memory life. */
5838 /* We do not know the size of a BLKmode store, so we do not track
5839 them for redundant store elimination. */
5840 && GET_MODE (reg) != BLKmode
5841 /* There are no REG_INC notes for SP, so we can't assume we'll see
5842 everything that invalidates it. To be safe, don't eliminate any
5843 stores though SP; none of them should be redundant anyway. */
5844 && ! reg_mentioned_p (stack_pointer_rtx, reg))
5847 /* Store a copy of mem, otherwise the address may be
5848 scrogged by find_auto_inc. */
5849 if (flags & PROP_AUTOINC)
5850 reg = shallow_copy_rtx (reg);
5852 pbi->mem_set_list = alloc_EXPR_LIST (0, reg, pbi->mem_set_list);
5853 pbi->mem_set_list_len++;
5857 if (GET_CODE (reg) == REG
5858 && ! (regno_first == FRAME_POINTER_REGNUM
5859 && (! reload_completed || frame_pointer_needed))
5860 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
5861 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
5862 && (! reload_completed || frame_pointer_needed))
5864 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
5865 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
5869 int some_was_live = 0, some_was_dead = 0;
5871 for (i = regno_first; i <= regno_last; ++i)
5873 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
5876 /* Order of the set operation matters here since both
5877 sets may be the same. */
5878 CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
5879 if (cond != NULL_RTX
5880 && ! REGNO_REG_SET_P (pbi->local_set, i))
5881 SET_REGNO_REG_SET (pbi->cond_local_set, i);
5883 SET_REGNO_REG_SET (pbi->local_set, i);
5885 if (code != CLOBBER)
5886 SET_REGNO_REG_SET (pbi->new_set, i);
5888 some_was_live |= needed_regno;
5889 some_was_dead |= ! needed_regno;
5892 #ifdef HAVE_conditional_execution
5893 /* Consider conditional death in deciding that the register needs
5895 if (some_was_live && ! not_dead
5896 /* The stack pointer is never dead. Well, not strictly true,
5897 but it's very difficult to tell from here. Hopefully
5898 combine_stack_adjustments will fix up the most egregious
5900 && regno_first != STACK_POINTER_REGNUM)
5902 for (i = regno_first; i <= regno_last; ++i)
5903 if (! mark_regno_cond_dead (pbi, i, cond))
5904 not_dead |= ((unsigned long) 1) << (i - regno_first);
5908 /* Additional data to record if this is the final pass. */
5909 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
5910 | PROP_DEATH_NOTES | PROP_AUTOINC))
5913 register int blocknum = pbi->bb->index;
5916 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
5918 y = pbi->reg_next_use[regno_first];
5920 /* The next use is no longer next, since a store intervenes. */
5921 for (i = regno_first; i <= regno_last; ++i)
5922 pbi->reg_next_use[i] = 0;
5925 if (flags & PROP_REG_INFO)
5927 for (i = regno_first; i <= regno_last; ++i)
5929 /* Count (weighted) references, stores, etc. This counts a
5930 register twice if it is modified, but that is correct. */
5931 REG_N_SETS (i) += 1;
5932 REG_N_REFS (i) += 1;
5933 REG_FREQ (i) += (optimize_size || !pbi->bb->frequency
5934 ? 1 : pbi->bb->frequency);
5936 /* The insns where a reg is live are normally counted
5937 elsewhere, but we want the count to include the insn
5938 where the reg is set, and the normal counting mechanism
5939 would not count it. */
5940 REG_LIVE_LENGTH (i) += 1;
5943 /* If this is a hard reg, record this function uses the reg. */
5944 if (regno_first < FIRST_PSEUDO_REGISTER)
5946 for (i = regno_first; i <= regno_last; i++)
5947 regs_ever_live[i] = 1;
5951 /* Keep track of which basic blocks each reg appears in. */
5952 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
5953 REG_BASIC_BLOCK (regno_first) = blocknum;
5954 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
5955 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
5959 if (! some_was_dead)
5961 if (flags & PROP_LOG_LINKS)
5963 /* Make a logical link from the next following insn
5964 that uses this register, back to this insn.
5965 The following insns have already been processed.
5967 We don't build a LOG_LINK for hard registers containing
5968 in ASM_OPERANDs. If these registers get replaced,
5969 we might wind up changing the semantics of the insn,
5970 even if reload can make what appear to be valid
5971 assignments later. */
5972 if (y && (BLOCK_NUM (y) == blocknum)
5973 && (regno_first >= FIRST_PSEUDO_REGISTER
5974 || asm_noperands (PATTERN (y)) < 0))
5975 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
5980 else if (! some_was_live)
5982 if (flags & PROP_REG_INFO)
5983 REG_N_DEATHS (regno_first) += 1;
5985 if (flags & PROP_DEATH_NOTES)
5987 /* Note that dead stores have already been deleted
5988 when possible. If we get here, we have found a
5989 dead store that cannot be eliminated (because the
5990 same insn does something useful). Indicate this
5991 by marking the reg being set as dying here. */
5993 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
5998 if (flags & PROP_DEATH_NOTES)
6000 /* This is a case where we have a multi-word hard register
6001 and some, but not all, of the words of the register are
6002 needed in subsequent insns. Write REG_UNUSED notes
6003 for those parts that were not needed. This case should
6006 for (i = regno_first; i <= regno_last; ++i)
6007 if (! REGNO_REG_SET_P (pbi->reg_live, i))
6009 = alloc_EXPR_LIST (REG_UNUSED,
6010 gen_rtx_REG (reg_raw_mode[i], i),
6016 /* Mark the register as being dead. */
6018 /* The stack pointer is never dead. Well, not strictly true,
6019 but it's very difficult to tell from here. Hopefully
6020 combine_stack_adjustments will fix up the most egregious
6022 && regno_first != STACK_POINTER_REGNUM)
6024 for (i = regno_first; i <= regno_last; ++i)
6025 if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
6026 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
6029 else if (GET_CODE (reg) == REG)
6031 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
6032 pbi->reg_next_use[regno_first] = 0;
6035 /* If this is the last pass and this is a SCRATCH, show it will be dying
6036 here and count it. */
6037 else if (GET_CODE (reg) == SCRATCH)
6039 if (flags & PROP_DEATH_NOTES)
6041 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
6045 #ifdef HAVE_conditional_execution
6046 /* Mark REGNO conditionally dead.
6047 Return true if the register is now unconditionally dead. */
6050 mark_regno_cond_dead (pbi, regno, cond)
6051 struct propagate_block_info *pbi;
6055 /* If this is a store to a predicate register, the value of the
6056 predicate is changing, we don't know that the predicate as seen
6057 before is the same as that seen after. Flush all dependent
6058 conditions from reg_cond_dead. This will make all such
6059 conditionally live registers unconditionally live. */
6060 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
6061 flush_reg_cond_reg (pbi, regno);
6063 /* If this is an unconditional store, remove any conditional
6064 life that may have existed. */
6065 if (cond == NULL_RTX)
6066 splay_tree_remove (pbi->reg_cond_dead, regno);
6069 splay_tree_node node;
6070 struct reg_cond_life_info *rcli;
6073 /* Otherwise this is a conditional set. Record that fact.
6074 It may have been conditionally used, or there may be a
6075 subsequent set with a complimentary condition. */
6077 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
6080 /* The register was unconditionally live previously.
6081 Record the current condition as the condition under
6082 which it is dead. */
6083 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
6084 rcli->condition = cond;
6085 rcli->stores = cond;
6086 rcli->orig_condition = const0_rtx;
6087 splay_tree_insert (pbi->reg_cond_dead, regno,
6088 (splay_tree_value) rcli);
6090 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
6092 /* Not unconditionaly dead. */
6097 /* The register was conditionally live previously.
6098 Add the new condition to the old. */
6099 rcli = (struct reg_cond_life_info *) node->value;
6100 ncond = rcli->condition;
6101 ncond = ior_reg_cond (ncond, cond, 1);
6102 if (rcli->stores == const0_rtx)
6103 rcli->stores = cond;
6104 else if (rcli->stores != const1_rtx)
6105 rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
6107 /* If the register is now unconditionally dead, remove the entry
6108 in the splay_tree. A register is unconditionally dead if the
6109 dead condition ncond is true. A register is also unconditionally
6110 dead if the sum of all conditional stores is an unconditional
6111 store (stores is true), and the dead condition is identically the
6112 same as the original dead condition initialized at the end of
6113 the block. This is a pointer compare, not an rtx_equal_p
6115 if (ncond == const1_rtx
6116 || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
6117 splay_tree_remove (pbi->reg_cond_dead, regno);
6120 rcli->condition = ncond;
6122 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
6124 /* Not unconditionaly dead. */
6133 /* Called from splay_tree_delete for pbi->reg_cond_life. */
6136 free_reg_cond_life_info (value)
6137 splay_tree_value value;
6139 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
6143 /* Helper function for flush_reg_cond_reg. */
6146 flush_reg_cond_reg_1 (node, data)
6147 splay_tree_node node;
6150 struct reg_cond_life_info *rcli;
6151 int *xdata = (int *) data;
6152 unsigned int regno = xdata[0];
6154 /* Don't need to search if last flushed value was farther on in
6155 the in-order traversal. */
6156 if (xdata[1] >= (int) node->key)
6159 /* Splice out portions of the expression that refer to regno. */
6160 rcli = (struct reg_cond_life_info *) node->value;
6161 rcli->condition = elim_reg_cond (rcli->condition, regno);
6162 if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
6163 rcli->stores = elim_reg_cond (rcli->stores, regno);
6165 /* If the entire condition is now false, signal the node to be removed. */
6166 if (rcli->condition == const0_rtx)
6168 xdata[1] = node->key;
6171 else if (rcli->condition == const1_rtx)
6177 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
6180 flush_reg_cond_reg (pbi, regno)
6181 struct propagate_block_info *pbi;
6188 while (splay_tree_foreach (pbi->reg_cond_dead,
6189 flush_reg_cond_reg_1, pair) == -1)
6190 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
6192 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
6195 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
6196 For ior/and, the ADD flag determines whether we want to add the new
6197 condition X to the old one unconditionally. If it is zero, we will
6198 only return a new expression if X allows us to simplify part of
6199 OLD, otherwise we return OLD unchanged to the caller.
6200 If ADD is nonzero, we will return a new condition in all cases. The
6201 toplevel caller of one of these functions should always pass 1 for
6205 ior_reg_cond (old, x, add)
6211 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
6213 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
6214 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
6215 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
6217 if (GET_CODE (x) == GET_CODE (old)
6218 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
6222 return gen_rtx_IOR (0, old, x);
6225 switch (GET_CODE (old))
6228 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
6229 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
6230 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
6232 if (op0 == const0_rtx)
6234 if (op1 == const0_rtx)
6236 if (op0 == const1_rtx || op1 == const1_rtx)
6238 if (op0 == XEXP (old, 0))
6239 op0 = gen_rtx_IOR (0, op0, x);
6241 op1 = gen_rtx_IOR (0, op1, x);
6242 return gen_rtx_IOR (0, op0, op1);
6246 return gen_rtx_IOR (0, old, x);
6249 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
6250 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
6251 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
6253 if (op0 == const1_rtx)
6255 if (op1 == const1_rtx)
6257 if (op0 == const0_rtx || op1 == const0_rtx)
6259 if (op0 == XEXP (old, 0))
6260 op0 = gen_rtx_IOR (0, op0, x);
6262 op1 = gen_rtx_IOR (0, op1, x);
6263 return gen_rtx_AND (0, op0, op1);
6267 return gen_rtx_IOR (0, old, x);
6270 op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
6271 if (op0 != XEXP (old, 0))
6272 return not_reg_cond (op0);
6275 return gen_rtx_IOR (0, old, x);
6286 enum rtx_code x_code;
6288 if (x == const0_rtx)
6290 else if (x == const1_rtx)
6292 x_code = GET_CODE (x);
6295 if (GET_RTX_CLASS (x_code) == '<'
6296 && GET_CODE (XEXP (x, 0)) == REG)
6298 if (XEXP (x, 1) != const0_rtx)
6301 return gen_rtx_fmt_ee (reverse_condition (x_code),
6302 VOIDmode, XEXP (x, 0), const0_rtx);
6304 return gen_rtx_NOT (0, x);
6308 and_reg_cond (old, x, add)
6314 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
6316 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
6317 && GET_CODE (x) == reverse_condition (GET_CODE (old))
6318 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
6320 if (GET_CODE (x) == GET_CODE (old)
6321 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
6325 return gen_rtx_AND (0, old, x);
6328 switch (GET_CODE (old))
6331 op0 = and_reg_cond (XEXP (old, 0), x, 0);
6332 op1 = and_reg_cond (XEXP (old, 1), x, 0);
6333 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
6335 if (op0 == const0_rtx)
6337 if (op1 == const0_rtx)
6339 if (op0 == const1_rtx || op1 == const1_rtx)
6341 if (op0 == XEXP (old, 0))
6342 op0 = gen_rtx_AND (0, op0, x);
6344 op1 = gen_rtx_AND (0, op1, x);
6345 return gen_rtx_IOR (0, op0, op1);
6349 return gen_rtx_AND (0, old, x);
6352 op0 = and_reg_cond (XEXP (old, 0), x, 0);
6353 op1 = and_reg_cond (XEXP (old, 1), x, 0);
6354 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
6356 if (op0 == const1_rtx)
6358 if (op1 == const1_rtx)
6360 if (op0 == const0_rtx || op1 == const0_rtx)
6362 if (op0 == XEXP (old, 0))
6363 op0 = gen_rtx_AND (0, op0, x);
6365 op1 = gen_rtx_AND (0, op1, x);
6366 return gen_rtx_AND (0, op0, op1);
6371 /* If X is identical to one of the existing terms of the AND,
6372 then just return what we already have. */
6373 /* ??? There really should be some sort of recursive check here in
6374 case there are nested ANDs. */
6375 if ((GET_CODE (XEXP (old, 0)) == GET_CODE (x)
6376 && REGNO (XEXP (XEXP (old, 0), 0)) == REGNO (XEXP (x, 0)))
6377 || (GET_CODE (XEXP (old, 1)) == GET_CODE (x)
6378 && REGNO (XEXP (XEXP (old, 1), 0)) == REGNO (XEXP (x, 0))))
6381 return gen_rtx_AND (0, old, x);
6384 op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
6385 if (op0 != XEXP (old, 0))
6386 return not_reg_cond (op0);
6389 return gen_rtx_AND (0, old, x);
6396 /* Given a condition X, remove references to reg REGNO and return the
6397 new condition. The removal will be done so that all conditions
6398 involving REGNO are considered to evaluate to false. This function
6399 is used when the value of REGNO changes. */
6402 elim_reg_cond (x, regno)
6408 if (GET_RTX_CLASS (GET_CODE (x)) == '<')
6410 if (REGNO (XEXP (x, 0)) == regno)
6415 switch (GET_CODE (x))
6418 op0 = elim_reg_cond (XEXP (x, 0), regno);
6419 op1 = elim_reg_cond (XEXP (x, 1), regno);
6420 if (op0 == const0_rtx || op1 == const0_rtx)
6422 if (op0 == const1_rtx)
6424 if (op1 == const1_rtx)
6426 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
6428 return gen_rtx_AND (0, op0, op1);
6431 op0 = elim_reg_cond (XEXP (x, 0), regno);
6432 op1 = elim_reg_cond (XEXP (x, 1), regno);
6433 if (op0 == const1_rtx || op1 == const1_rtx)
6435 if (op0 == const0_rtx)
6437 if (op1 == const0_rtx)
6439 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
6441 return gen_rtx_IOR (0, op0, op1);
6444 op0 = elim_reg_cond (XEXP (x, 0), regno);
6445 if (op0 == const0_rtx)
6447 if (op0 == const1_rtx)
6449 if (op0 != XEXP (x, 0))
6450 return not_reg_cond (op0);
6457 #endif /* HAVE_conditional_execution */
6461 /* Try to substitute the auto-inc expression INC as the address inside
6462 MEM which occurs in INSN. Currently, the address of MEM is an expression
6463 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
6464 that has a single set whose source is a PLUS of INCR_REG and something
6468 attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
6469 struct propagate_block_info *pbi;
6470 rtx inc, insn, mem, incr, incr_reg;
6472 int regno = REGNO (incr_reg);
6473 rtx set = single_set (incr);
6474 rtx q = SET_DEST (set);
6475 rtx y = SET_SRC (set);
6476 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
6478 /* Make sure this reg appears only once in this insn. */
6479 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
6482 if (dead_or_set_p (incr, incr_reg)
6483 /* Mustn't autoinc an eliminable register. */
6484 && (regno >= FIRST_PSEUDO_REGISTER
6485 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
6487 /* This is the simple case. Try to make the auto-inc. If
6488 we can't, we are done. Otherwise, we will do any
6489 needed updates below. */
6490 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
6493 else if (GET_CODE (q) == REG
6494 /* PREV_INSN used here to check the semi-open interval
6496 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
6497 /* We must also check for sets of q as q may be
6498 a call clobbered hard register and there may
6499 be a call between PREV_INSN (insn) and incr. */
6500 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
6502 /* We have *p followed sometime later by q = p+size.
6503 Both p and q must be live afterward,
6504 and q is not used between INSN and its assignment.
6505 Change it to q = p, ...*q..., q = q+size.
6506 Then fall into the usual case. */
6510 emit_move_insn (q, incr_reg);
6511 insns = get_insns ();
6514 if (basic_block_for_insn)
6515 for (temp = insns; temp; temp = NEXT_INSN (temp))
6516 set_block_for_insn (temp, pbi->bb);
6518 /* If we can't make the auto-inc, or can't make the
6519 replacement into Y, exit. There's no point in making
6520 the change below if we can't do the auto-inc and doing
6521 so is not correct in the pre-inc case. */
6524 validate_change (insn, &XEXP (mem, 0), inc, 1);
6525 validate_change (incr, &XEXP (y, opnum), q, 1);
6526 if (! apply_change_group ())
6529 /* We now know we'll be doing this change, so emit the
6530 new insn(s) and do the updates. */
6531 emit_insns_before (insns, insn);
6533 if (pbi->bb->head == insn)
6534 pbi->bb->head = insns;
6536 /* INCR will become a NOTE and INSN won't contain a
6537 use of INCR_REG. If a use of INCR_REG was just placed in
6538 the insn before INSN, make that the next use.
6539 Otherwise, invalidate it. */
6540 if (GET_CODE (PREV_INSN (insn)) == INSN
6541 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
6542 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
6543 pbi->reg_next_use[regno] = PREV_INSN (insn);
6545 pbi->reg_next_use[regno] = 0;
6550 /* REGNO is now used in INCR which is below INSN, but
6551 it previously wasn't live here. If we don't mark
6552 it as live, we'll put a REG_DEAD note for it
6553 on this insn, which is incorrect. */
6554 SET_REGNO_REG_SET (pbi->reg_live, regno);
6556 /* If there are any calls between INSN and INCR, show
6557 that REGNO now crosses them. */
6558 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
6559 if (GET_CODE (temp) == CALL_INSN)
6560 REG_N_CALLS_CROSSED (regno)++;
6565 /* If we haven't returned, it means we were able to make the
6566 auto-inc, so update the status. First, record that this insn
6567 has an implicit side effect. */
6569 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
6571 /* Modify the old increment-insn to simply copy
6572 the already-incremented value of our register. */
6573 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
6576 /* If that makes it a no-op (copying the register into itself) delete
6577 it so it won't appear to be a "use" and a "set" of this
6579 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
6581 /* If the original source was dead, it's dead now. */
6584 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
6586 remove_note (incr, note);
6587 if (XEXP (note, 0) != incr_reg)
6588 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
6591 PUT_CODE (incr, NOTE);
6592 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
6593 NOTE_SOURCE_FILE (incr) = 0;
6596 if (regno >= FIRST_PSEUDO_REGISTER)
6598 /* Count an extra reference to the reg. When a reg is
6599 incremented, spilling it is worse, so we want to make
6600 that less likely. */
6601 REG_FREQ (regno) += (optimize_size || !pbi->bb->frequency
6602 ? 1 : pbi->bb->frequency);
6604 /* Count the increment as a setting of the register,
6605 even though it isn't a SET in rtl. */
6606 REG_N_SETS (regno)++;
6610 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
6614 find_auto_inc (pbi, x, insn)
6615 struct propagate_block_info *pbi;
6619 rtx addr = XEXP (x, 0);
6620 HOST_WIDE_INT offset = 0;
6621 rtx set, y, incr, inc_val;
6623 int size = GET_MODE_SIZE (GET_MODE (x));
6625 if (GET_CODE (insn) == JUMP_INSN)
6628 /* Here we detect use of an index register which might be good for
6629 postincrement, postdecrement, preincrement, or predecrement. */
6631 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
6632 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
6634 if (GET_CODE (addr) != REG)
6637 regno = REGNO (addr);
6639 /* Is the next use an increment that might make auto-increment? */
6640 incr = pbi->reg_next_use[regno];
6641 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
6643 set = single_set (incr);
6644 if (set == 0 || GET_CODE (set) != SET)
6648 if (GET_CODE (y) != PLUS)
6651 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
6652 inc_val = XEXP (y, 1);
6653 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
6654 inc_val = XEXP (y, 0);
6658 if (GET_CODE (inc_val) == CONST_INT)
6660 if (HAVE_POST_INCREMENT
6661 && (INTVAL (inc_val) == size && offset == 0))
6662 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
6664 else if (HAVE_POST_DECREMENT
6665 && (INTVAL (inc_val) == -size && offset == 0))
6666 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
6668 else if (HAVE_PRE_INCREMENT
6669 && (INTVAL (inc_val) == size && offset == size))
6670 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
6672 else if (HAVE_PRE_DECREMENT
6673 && (INTVAL (inc_val) == -size && offset == -size))
6674 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
6676 else if (HAVE_POST_MODIFY_DISP && offset == 0)
6677 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
6678 gen_rtx_PLUS (Pmode,
6681 insn, x, incr, addr);
6683 else if (GET_CODE (inc_val) == REG
6684 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
6688 if (HAVE_POST_MODIFY_REG && offset == 0)
6689 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
6690 gen_rtx_PLUS (Pmode,
6693 insn, x, incr, addr);
6697 #endif /* AUTO_INC_DEC */
6700 mark_used_reg (pbi, reg, cond, insn)
6701 struct propagate_block_info *pbi;
6703 rtx cond ATTRIBUTE_UNUSED;
6706 unsigned int regno_first, regno_last, i;
6707 int some_was_live, some_was_dead, some_not_set;
6709 regno_last = regno_first = REGNO (reg);
6710 if (regno_first < FIRST_PSEUDO_REGISTER)
6711 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
6713 /* Find out if any of this register is live after this instruction. */
6714 some_was_live = some_was_dead = 0;
6715 for (i = regno_first; i <= regno_last; ++i)
6717 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
6718 some_was_live |= needed_regno;
6719 some_was_dead |= ! needed_regno;
6722 /* Find out if any of the register was set this insn. */
6724 for (i = regno_first; i <= regno_last; ++i)
6725 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
6727 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
6729 /* Record where each reg is used, so when the reg is set we know
6730 the next insn that uses it. */
6731 pbi->reg_next_use[regno_first] = insn;
6734 if (pbi->flags & PROP_REG_INFO)
6736 if (regno_first < FIRST_PSEUDO_REGISTER)
6738 /* If this is a register we are going to try to eliminate,
6739 don't mark it live here. If we are successful in
6740 eliminating it, it need not be live unless it is used for
6741 pseudos, in which case it will have been set live when it
6742 was allocated to the pseudos. If the register will not
6743 be eliminated, reload will set it live at that point.
6745 Otherwise, record that this function uses this register. */
6746 /* ??? The PPC backend tries to "eliminate" on the pic
6747 register to itself. This should be fixed. In the mean
6748 time, hack around it. */
6750 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
6751 && (regno_first == FRAME_POINTER_REGNUM
6752 || regno_first == ARG_POINTER_REGNUM)))
6753 for (i = regno_first; i <= regno_last; ++i)
6754 regs_ever_live[i] = 1;
6758 /* Keep track of which basic block each reg appears in. */
6760 register int blocknum = pbi->bb->index;
6761 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
6762 REG_BASIC_BLOCK (regno_first) = blocknum;
6763 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
6764 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
6766 /* Count (weighted) number of uses of each reg. */
6767 REG_FREQ (regno_first)
6768 += (optimize_size || !pbi->bb->frequency ? 1 : pbi->bb->frequency);
6769 REG_N_REFS (regno_first)++;
6773 /* Record and count the insns in which a reg dies. If it is used in
6774 this insn and was dead below the insn then it dies in this insn.
6775 If it was set in this insn, we do not make a REG_DEAD note;
6776 likewise if we already made such a note. */
6777 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
6781 /* Check for the case where the register dying partially
6782 overlaps the register set by this insn. */
6783 if (regno_first != regno_last)
6784 for (i = regno_first; i <= regno_last; ++i)
6785 some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
6787 /* If none of the words in X is needed, make a REG_DEAD note.
6788 Otherwise, we must make partial REG_DEAD notes. */
6789 if (! some_was_live)
6791 if ((pbi->flags & PROP_DEATH_NOTES)
6792 && ! find_regno_note (insn, REG_DEAD, regno_first))
6794 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
6796 if (pbi->flags & PROP_REG_INFO)
6797 REG_N_DEATHS (regno_first)++;
6801 /* Don't make a REG_DEAD note for a part of a register
6802 that is set in the insn. */
6803 for (i = regno_first; i <= regno_last; ++i)
6804 if (! REGNO_REG_SET_P (pbi->reg_live, i)
6805 && ! dead_or_set_regno_p (insn, i))
6807 = alloc_EXPR_LIST (REG_DEAD,
6808 gen_rtx_REG (reg_raw_mode[i], i),
6813 /* Mark the register as being live. */
6814 for (i = regno_first; i <= regno_last; ++i)
6816 SET_REGNO_REG_SET (pbi->reg_live, i);
6818 #ifdef HAVE_conditional_execution
6819 /* If this is a conditional use, record that fact. If it is later
6820 conditionally set, we'll know to kill the register. */
6821 if (cond != NULL_RTX)
6823 splay_tree_node node;
6824 struct reg_cond_life_info *rcli;
6829 node = splay_tree_lookup (pbi->reg_cond_dead, i);
6832 /* The register was unconditionally live previously.
6833 No need to do anything. */
6837 /* The register was conditionally live previously.
6838 Subtract the new life cond from the old death cond. */
6839 rcli = (struct reg_cond_life_info *) node->value;
6840 ncond = rcli->condition;
6841 ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
6843 /* If the register is now unconditionally live,
6844 remove the entry in the splay_tree. */
6845 if (ncond == const0_rtx)
6846 splay_tree_remove (pbi->reg_cond_dead, i);
6849 rcli->condition = ncond;
6850 SET_REGNO_REG_SET (pbi->reg_cond_reg,
6851 REGNO (XEXP (cond, 0)));
6857 /* The register was not previously live at all. Record
6858 the condition under which it is still dead. */
6859 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
6860 rcli->condition = not_reg_cond (cond);
6861 rcli->stores = const0_rtx;
6862 rcli->orig_condition = const0_rtx;
6863 splay_tree_insert (pbi->reg_cond_dead, i,
6864 (splay_tree_value) rcli);
6866 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
6869 else if (some_was_live)
6871 /* The register may have been conditionally live previously, but
6872 is now unconditionally live. Remove it from the conditionally
6873 dead list, so that a conditional set won't cause us to think
6875 splay_tree_remove (pbi->reg_cond_dead, i);
6881 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
6882 This is done assuming the registers needed from X are those that
6883 have 1-bits in PBI->REG_LIVE.
6885 INSN is the containing instruction. If INSN is dead, this function
6889 mark_used_regs (pbi, x, cond, insn)
6890 struct propagate_block_info *pbi;
6893 register RTX_CODE code;
6895 int flags = pbi->flags;
6898 code = GET_CODE (x);
6918 /* If we are clobbering a MEM, mark any registers inside the address
6920 if (GET_CODE (XEXP (x, 0)) == MEM)
6921 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
6925 /* Don't bother watching stores to mems if this is not the
6926 final pass. We'll not be deleting dead stores this round. */
6927 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
6929 /* Invalidate the data for the last MEM stored, but only if MEM is
6930 something that can be stored into. */
6931 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
6932 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
6933 /* Needn't clear the memory set list. */
6937 rtx temp = pbi->mem_set_list;
6938 rtx prev = NULL_RTX;
6943 next = XEXP (temp, 1);
6944 if (anti_dependence (XEXP (temp, 0), x))
6946 /* Splice temp out of the list. */
6948 XEXP (prev, 1) = next;
6950 pbi->mem_set_list = next;
6951 free_EXPR_LIST_node (temp);
6952 pbi->mem_set_list_len--;
6960 /* If the memory reference had embedded side effects (autoincrement
6961 address modes. Then we may need to kill some entries on the
6964 invalidate_mems_from_autoinc (pbi, insn);
6968 if (flags & PROP_AUTOINC)
6969 find_auto_inc (pbi, x, insn);
6974 #ifdef CLASS_CANNOT_CHANGE_MODE
6975 if (GET_CODE (SUBREG_REG (x)) == REG
6976 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
6977 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
6978 GET_MODE (SUBREG_REG (x))))
6979 REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
6982 /* While we're here, optimize this case. */
6984 if (GET_CODE (x) != REG)
6989 /* See a register other than being set => mark it as needed. */
6990 mark_used_reg (pbi, x, cond, insn);
6995 register rtx testreg = SET_DEST (x);
6998 /* If storing into MEM, don't show it as being used. But do
6999 show the address as being used. */
7000 if (GET_CODE (testreg) == MEM)
7003 if (flags & PROP_AUTOINC)
7004 find_auto_inc (pbi, testreg, insn);
7006 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
7007 mark_used_regs (pbi, SET_SRC (x), cond, insn);
7011 /* Storing in STRICT_LOW_PART is like storing in a reg
7012 in that this SET might be dead, so ignore it in TESTREG.
7013 but in some other ways it is like using the reg.
7015 Storing in a SUBREG or a bit field is like storing the entire
7016 register in that if the register's value is not used
7017 then this SET is not needed. */
7018 while (GET_CODE (testreg) == STRICT_LOW_PART
7019 || GET_CODE (testreg) == ZERO_EXTRACT
7020 || GET_CODE (testreg) == SIGN_EXTRACT
7021 || GET_CODE (testreg) == SUBREG)
7023 #ifdef CLASS_CANNOT_CHANGE_MODE
7024 if (GET_CODE (testreg) == SUBREG
7025 && GET_CODE (SUBREG_REG (testreg)) == REG
7026 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
7027 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
7028 GET_MODE (testreg)))
7029 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
7032 /* Modifying a single register in an alternate mode
7033 does not use any of the old value. But these other
7034 ways of storing in a register do use the old value. */
7035 if (GET_CODE (testreg) == SUBREG
7036 && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
7041 testreg = XEXP (testreg, 0);
7044 /* If this is a store into a register or group of registers,
7045 recursively scan the value being stored. */
7047 if ((GET_CODE (testreg) == PARALLEL
7048 && GET_MODE (testreg) == BLKmode)
7049 || (GET_CODE (testreg) == REG
7050 && (regno = REGNO (testreg),
7051 ! (regno == FRAME_POINTER_REGNUM
7052 && (! reload_completed || frame_pointer_needed)))
7053 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
7054 && ! (regno == HARD_FRAME_POINTER_REGNUM
7055 && (! reload_completed || frame_pointer_needed))
7057 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
7058 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
7063 mark_used_regs (pbi, SET_DEST (x), cond, insn);
7064 mark_used_regs (pbi, SET_SRC (x), cond, insn);
7071 case UNSPEC_VOLATILE:
7075 /* Traditional and volatile asm instructions must be considered to use
7076 and clobber all hard registers, all pseudo-registers and all of
7077 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
7079 Consider for instance a volatile asm that changes the fpu rounding
7080 mode. An insn should not be moved across this even if it only uses
7081 pseudo-regs because it might give an incorrectly rounded result.
7083 ?!? Unfortunately, marking all hard registers as live causes massive
7084 problems for the register allocator and marking all pseudos as live
7085 creates mountains of uninitialized variable warnings.
7087 So for now, just clear the memory set list and mark any regs
7088 we can find in ASM_OPERANDS as used. */
7089 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
7091 free_EXPR_LIST_list (&pbi->mem_set_list);
7092 pbi->mem_set_list_len = 0;
7095 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
7096 We can not just fall through here since then we would be confused
7097 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
7098 traditional asms unlike their normal usage. */
7099 if (code == ASM_OPERANDS)
7103 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
7104 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
7110 if (cond != NULL_RTX)
7113 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
7115 cond = COND_EXEC_TEST (x);
7116 x = COND_EXEC_CODE (x);
7120 /* We _do_not_ want to scan operands of phi nodes. Operands of
7121 a phi function are evaluated only when control reaches this
7122 block along a particular edge. Therefore, regs that appear
7123 as arguments to phi should not be added to the global live at
7131 /* Recursively scan the operands of this expression. */
7134 register const char *fmt = GET_RTX_FORMAT (code);
7137 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
7141 /* Tail recursive case: save a function call level. */
7147 mark_used_regs (pbi, XEXP (x, i), cond, insn);
7149 else if (fmt[i] == 'E')
7152 for (j = 0; j < XVECLEN (x, i); j++)
7153 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
7162 try_pre_increment_1 (pbi, insn)
7163 struct propagate_block_info *pbi;
7166 /* Find the next use of this reg. If in same basic block,
7167 make it do pre-increment or pre-decrement if appropriate. */
7168 rtx x = single_set (insn);
7169 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
7170 * INTVAL (XEXP (SET_SRC (x), 1)));
7171 int regno = REGNO (SET_DEST (x));
7172 rtx y = pbi->reg_next_use[regno];
7174 && SET_DEST (x) != stack_pointer_rtx
7175 && BLOCK_NUM (y) == BLOCK_NUM (insn)
7176 /* Don't do this if the reg dies, or gets set in y; a standard addressing
7177 mode would be better. */
7178 && ! dead_or_set_p (y, SET_DEST (x))
7179 && try_pre_increment (y, SET_DEST (x), amount))
7181 /* We have found a suitable auto-increment and already changed
7182 insn Y to do it. So flush this increment instruction. */
7183 propagate_block_delete_insn (pbi->bb, insn);
7185 /* Count a reference to this reg for the increment insn we are
7186 deleting. When a reg is incremented, spilling it is worse,
7187 so we want to make that less likely. */
7188 if (regno >= FIRST_PSEUDO_REGISTER)
7190 REG_FREQ (regno) += (optimize_size || !pbi->bb->frequency
7191 ? 1 : pbi->bb->frequency);
7192 REG_N_SETS (regno)++;
7195 /* Flush any remembered memories depending on the value of
7196 the incremented register. */
7197 invalidate_mems_from_set (pbi, SET_DEST (x));
7204 /* Try to change INSN so that it does pre-increment or pre-decrement
7205 addressing on register REG in order to add AMOUNT to REG.
7206 AMOUNT is negative for pre-decrement.
7207 Returns 1 if the change could be made.
7208 This checks all about the validity of the result of modifying INSN. */
7211 try_pre_increment (insn, reg, amount)
7213 HOST_WIDE_INT amount;
7217 /* Nonzero if we can try to make a pre-increment or pre-decrement.
7218 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
7220 /* Nonzero if we can try to make a post-increment or post-decrement.
7221 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
7222 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
7223 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
7226 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
7229 /* From the sign of increment, see which possibilities are conceivable
7230 on this target machine. */
7231 if (HAVE_PRE_INCREMENT && amount > 0)
7233 if (HAVE_POST_INCREMENT && amount > 0)
7236 if (HAVE_PRE_DECREMENT && amount < 0)
7238 if (HAVE_POST_DECREMENT && amount < 0)
7241 if (! (pre_ok || post_ok))
7244 /* It is not safe to add a side effect to a jump insn
7245 because if the incremented register is spilled and must be reloaded
7246 there would be no way to store the incremented value back in memory. */
7248 if (GET_CODE (insn) == JUMP_INSN)
7253 use = find_use_as_address (PATTERN (insn), reg, 0);
7254 if (post_ok && (use == 0 || use == (rtx) 1))
7256 use = find_use_as_address (PATTERN (insn), reg, -amount);
7260 if (use == 0 || use == (rtx) 1)
7263 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
7266 /* See if this combination of instruction and addressing mode exists. */
7267 if (! validate_change (insn, &XEXP (use, 0),
7268 gen_rtx_fmt_e (amount > 0
7269 ? (do_post ? POST_INC : PRE_INC)
7270 : (do_post ? POST_DEC : PRE_DEC),
7274 /* Record that this insn now has an implicit side effect on X. */
7275 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
7279 #endif /* AUTO_INC_DEC */
7281 /* Find the place in the rtx X where REG is used as a memory address.
7282 Return the MEM rtx that so uses it.
7283 If PLUSCONST is nonzero, search instead for a memory address equivalent to
7284 (plus REG (const_int PLUSCONST)).
7286 If such an address does not appear, return 0.
7287 If REG appears more than once, or is used other than in such an address,
7291 find_use_as_address (x, reg, plusconst)
7294 HOST_WIDE_INT plusconst;
7296 enum rtx_code code = GET_CODE (x);
7297 const char *fmt = GET_RTX_FORMAT (code);
7299 register rtx value = 0;
7302 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
7305 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
7306 && XEXP (XEXP (x, 0), 0) == reg
7307 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
7308 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
7311 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
7313 /* If REG occurs inside a MEM used in a bit-field reference,
7314 that is unacceptable. */
7315 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
7316 return (rtx) (HOST_WIDE_INT) 1;
7320 return (rtx) (HOST_WIDE_INT) 1;
7322 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
7326 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
7330 return (rtx) (HOST_WIDE_INT) 1;
7332 else if (fmt[i] == 'E')
7335 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
7337 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
7341 return (rtx) (HOST_WIDE_INT) 1;
7349 /* Write information about registers and basic blocks into FILE.
7350 This is part of making a debugging dump. */
7353 dump_regset (r, outf)
7360 fputs (" (nil)", outf);
7364 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
7366 fprintf (outf, " %d", i);
7367 if (i < FIRST_PSEUDO_REGISTER)
7368 fprintf (outf, " [%s]",
7373 /* Print a human-reaable representation of R on the standard error
7374 stream. This function is designed to be used from within the
7381 dump_regset (r, stderr);
7382 putc ('\n', stderr);
7386 dump_flow_info (file)
7390 static const char * const reg_class_names[] = REG_CLASS_NAMES;
7392 fprintf (file, "%d registers.\n", max_regno);
7393 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
7396 enum reg_class class, altclass;
7397 fprintf (file, "\nRegister %d used %d times across %d insns",
7398 i, REG_N_REFS (i), REG_LIVE_LENGTH (i));
7399 if (REG_BASIC_BLOCK (i) >= 0)
7400 fprintf (file, " in block %d", REG_BASIC_BLOCK (i));
7402 fprintf (file, "; set %d time%s", REG_N_SETS (i),
7403 (REG_N_SETS (i) == 1) ? "" : "s");
7404 if (REG_USERVAR_P (regno_reg_rtx[i]))
7405 fprintf (file, "; user var");
7406 if (REG_N_DEATHS (i) != 1)
7407 fprintf (file, "; dies in %d places", REG_N_DEATHS (i));
7408 if (REG_N_CALLS_CROSSED (i) == 1)
7409 fprintf (file, "; crosses 1 call");
7410 else if (REG_N_CALLS_CROSSED (i))
7411 fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i));
7412 if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
7413 fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
7414 class = reg_preferred_class (i);
7415 altclass = reg_alternate_class (i);
7416 if (class != GENERAL_REGS || altclass != ALL_REGS)
7418 if (altclass == ALL_REGS || class == ALL_REGS)
7419 fprintf (file, "; pref %s", reg_class_names[(int) class]);
7420 else if (altclass == NO_REGS)
7421 fprintf (file, "; %s or none", reg_class_names[(int) class]);
7423 fprintf (file, "; pref %s, else %s",
7424 reg_class_names[(int) class],
7425 reg_class_names[(int) altclass]);
7427 if (REG_POINTER (regno_reg_rtx[i]))
7428 fprintf (file, "; pointer");
7429 fprintf (file, ".\n");
7432 fprintf (file, "\n%d basic blocks, %d edges.\n", n_basic_blocks, n_edges);
7433 for (i = 0; i < n_basic_blocks; i++)
7435 register basic_block bb = BASIC_BLOCK (i);
7438 fprintf (file, "\nBasic block %d: first insn %d, last %d, loop_depth %d, count ",
7439 i, INSN_UID (bb->head), INSN_UID (bb->end), bb->loop_depth);
7440 fprintf (file, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT) bb->count);
7441 fprintf (file, ", freq %i.\n", bb->frequency);
7443 fprintf (file, "Predecessors: ");
7444 for (e = bb->pred; e; e = e->pred_next)
7445 dump_edge_info (file, e, 0);
7447 fprintf (file, "\nSuccessors: ");
7448 for (e = bb->succ; e; e = e->succ_next)
7449 dump_edge_info (file, e, 1);
7451 fprintf (file, "\nRegisters live at start:");
7452 dump_regset (bb->global_live_at_start, file);
7454 fprintf (file, "\nRegisters live at end:");
7455 dump_regset (bb->global_live_at_end, file);
7466 dump_flow_info (stderr);
7470 dump_edge_info (file, e, do_succ)
7475 basic_block side = (do_succ ? e->dest : e->src);
7477 if (side == ENTRY_BLOCK_PTR)
7478 fputs (" ENTRY", file);
7479 else if (side == EXIT_BLOCK_PTR)
7480 fputs (" EXIT", file);
7482 fprintf (file, " %d", side->index);
7485 fprintf (file, " [%.1f%%] ", e->probability * 100.0 / REG_BR_PROB_BASE);
7489 fprintf (file, " count:");
7490 fprintf (file, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT) e->count);
7495 static const char * const bitnames[] = {
7496 "fallthru", "crit", "ab", "abcall", "eh", "fake"
7499 int i, flags = e->flags;
7503 for (i = 0; flags; i++)
7504 if (flags & (1 << i))
7510 if (i < (int) ARRAY_SIZE (bitnames))
7511 fputs (bitnames[i], file);
7513 fprintf (file, "%d", i);
7520 /* Print out one basic block with live information at start and end. */
7531 fprintf (outf, ";; Basic block %d, loop depth %d, count ",
7532 bb->index, bb->loop_depth);
7533 fprintf (outf, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT) bb->count);
7536 fputs (";; Predecessors: ", outf);
7537 for (e = bb->pred; e; e = e->pred_next)
7538 dump_edge_info (outf, e, 0);
7541 fputs (";; Registers live at start:", outf);
7542 dump_regset (bb->global_live_at_start, outf);
7545 for (insn = bb->head, last = NEXT_INSN (bb->end);
7547 insn = NEXT_INSN (insn))
7548 print_rtl_single (outf, insn);
7550 fputs (";; Registers live at end:", outf);
7551 dump_regset (bb->global_live_at_end, outf);
7554 fputs (";; Successors: ", outf);
7555 for (e = bb->succ; e; e = e->succ_next)
7556 dump_edge_info (outf, e, 1);
7564 dump_bb (bb, stderr);
7571 dump_bb (BASIC_BLOCK (n), stderr);
7574 /* Like print_rtl, but also print out live information for the start of each
7578 print_rtl_with_bb (outf, rtx_first)
7582 register rtx tmp_rtx;
7585 fprintf (outf, "(nil)\n");
7589 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
7590 int max_uid = get_max_uid ();
7591 basic_block *start = (basic_block *)
7592 xcalloc (max_uid, sizeof (basic_block));
7593 basic_block *end = (basic_block *)
7594 xcalloc (max_uid, sizeof (basic_block));
7595 enum bb_state *in_bb_p = (enum bb_state *)
7596 xcalloc (max_uid, sizeof (enum bb_state));
7598 for (i = n_basic_blocks - 1; i >= 0; i--)
7600 basic_block bb = BASIC_BLOCK (i);
7603 start[INSN_UID (bb->head)] = bb;
7604 end[INSN_UID (bb->end)] = bb;
7605 for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x))
7607 enum bb_state state = IN_MULTIPLE_BB;
7608 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
7610 in_bb_p[INSN_UID (x)] = state;
7617 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
7622 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
7624 fprintf (outf, ";; Start of basic block %d, registers live:",
7626 dump_regset (bb->global_live_at_start, outf);
7630 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
7631 && GET_CODE (tmp_rtx) != NOTE
7632 && GET_CODE (tmp_rtx) != BARRIER)
7633 fprintf (outf, ";; Insn is not within a basic block\n");
7634 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
7635 fprintf (outf, ";; Insn is in multiple basic blocks\n");
7637 did_output = print_rtl_single (outf, tmp_rtx);
7639 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
7641 fprintf (outf, ";; End of basic block %d, registers live:\n",
7643 dump_regset (bb->global_live_at_end, outf);
7656 if (current_function_epilogue_delay_list != 0)
7658 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
7659 for (tmp_rtx = current_function_epilogue_delay_list; tmp_rtx != 0;
7660 tmp_rtx = XEXP (tmp_rtx, 1))
7661 print_rtl_single (outf, XEXP (tmp_rtx, 0));
7665 /* Dump the rtl into the current debugging dump file, then abort. */
7668 print_rtl_and_abort_fcn (file, line, function)
7671 const char *function;
7675 print_rtl_with_bb (rtl_dump_file, get_insns ());
7676 fclose (rtl_dump_file);
7679 fancy_abort (file, line, function);
7682 /* Recompute register set/reference counts immediately prior to register
7685 This avoids problems with set/reference counts changing to/from values
7686 which have special meanings to the register allocators.
7688 Additionally, the reference counts are the primary component used by the
7689 register allocators to prioritize pseudos for allocation to hard regs.
7690 More accurate reference counts generally lead to better register allocation.
7692 F is the first insn to be scanned.
7694 LOOP_STEP denotes how much loop_depth should be incremented per
7695 loop nesting level in order to increase the ref count more for
7696 references in a loop.
7698 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
7699 possibly other information which is used by the register allocators. */
7702 recompute_reg_usage (f, loop_step)
7703 rtx f ATTRIBUTE_UNUSED;
7704 int loop_step ATTRIBUTE_UNUSED;
7706 allocate_reg_life_data ();
7707 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
7710 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
7711 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
7712 of the number of registers that died. */
7715 count_or_remove_death_notes (blocks, kill)
7721 for (i = n_basic_blocks - 1; i >= 0; --i)
7726 if (blocks && ! TEST_BIT (blocks, i))
7729 bb = BASIC_BLOCK (i);
7731 for (insn = bb->head;; insn = NEXT_INSN (insn))
7735 rtx *pprev = ®_NOTES (insn);
7740 switch (REG_NOTE_KIND (link))
7743 if (GET_CODE (XEXP (link, 0)) == REG)
7745 rtx reg = XEXP (link, 0);
7748 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
7751 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
7759 rtx next = XEXP (link, 1);
7760 free_EXPR_LIST_node (link);
7761 *pprev = link = next;
7767 pprev = &XEXP (link, 1);
7774 if (insn == bb->end)
7783 /* Update insns block within BB. */
7786 update_bb_for_insn (bb)
7791 if (! basic_block_for_insn)
7794 for (insn = bb->head; ; insn = NEXT_INSN (insn))
7796 set_block_for_insn (insn, bb);
7798 if (insn == bb->end)
7804 /* Record INSN's block as BB. */
7807 set_block_for_insn (insn, bb)
7811 size_t uid = INSN_UID (insn);
7812 if (uid >= basic_block_for_insn->num_elements)
7816 /* Add one-eighth the size so we don't keep calling xrealloc. */
7817 new_size = uid + (uid + 7) / 8;
7819 VARRAY_GROW (basic_block_for_insn, new_size);
7821 VARRAY_BB (basic_block_for_insn, uid) = bb;
7824 /* When a new insn has been inserted into an existing block, it will
7825 sometimes emit more than a single insn. This routine will set the
7826 block number for the specified insn, and look backwards in the insn
7827 chain to see if there are any other uninitialized insns immediately
7828 previous to this one, and set the block number for them too. */
7831 set_block_for_new_insns (insn, bb)
7835 set_block_for_insn (insn, bb);
7837 /* Scan the previous instructions setting the block number until we find
7838 an instruction that has the block number set, or we find a note
7840 for (insn = PREV_INSN (insn); insn != NULL_RTX; insn = PREV_INSN (insn))
7842 if (GET_CODE (insn) == NOTE)
7844 if (INSN_UID (insn) >= basic_block_for_insn->num_elements
7845 || BLOCK_FOR_INSN (insn) == 0)
7846 set_block_for_insn (insn, bb);
7852 /* Verify the CFG consistency. This function check some CFG invariants and
7853 aborts when something is wrong. Hope that this function will help to
7854 convert many optimization passes to preserve CFG consistent.
7856 Currently it does following checks:
7858 - test head/end pointers
7859 - overlapping of basic blocks
7860 - edge list corectness
7861 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
7862 - tails of basic blocks (ensure that boundary is necesary)
7863 - scans body of the basic block for JUMP_INSN, CODE_LABEL
7864 and NOTE_INSN_BASIC_BLOCK
7865 - check that all insns are in the basic blocks
7866 (except the switch handling code, barriers and notes)
7867 - check that all returns are followed by barriers
7869 In future it can be extended check a lot of other stuff as well
7870 (reachability of basic blocks, life information, etc. etc.). */
7875 const int max_uid = get_max_uid ();
7876 const rtx rtx_first = get_insns ();
7877 rtx last_head = get_last_insn ();
7878 basic_block *bb_info;
7880 int i, last_bb_num_seen, num_bb_notes, err = 0;
7882 bb_info = (basic_block *) xcalloc (max_uid, sizeof (basic_block));
7884 for (i = n_basic_blocks - 1; i >= 0; i--)
7886 basic_block bb = BASIC_BLOCK (i);
7887 rtx head = bb->head;
7890 /* Verify the end of the basic block is in the INSN chain. */
7891 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
7896 error ("End insn %d for block %d not found in the insn stream.",
7897 INSN_UID (end), bb->index);
7901 /* Work backwards from the end to the head of the basic block
7902 to verify the head is in the RTL chain. */
7903 for (; x != NULL_RTX; x = PREV_INSN (x))
7905 /* While walking over the insn chain, verify insns appear
7906 in only one basic block and initialize the BB_INFO array
7907 used by other passes. */
7908 if (bb_info[INSN_UID (x)] != NULL)
7910 error ("Insn %d is in multiple basic blocks (%d and %d)",
7911 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
7914 bb_info[INSN_UID (x)] = bb;
7921 error ("Head insn %d for block %d not found in the insn stream.",
7922 INSN_UID (head), bb->index);
7929 /* Now check the basic blocks (boundaries etc.) */
7930 for (i = n_basic_blocks - 1; i >= 0; i--)
7932 basic_block bb = BASIC_BLOCK (i);
7933 /* Check corectness of edge lists */
7939 if ((e->flags & EDGE_FALLTHRU)
7940 && e->src != ENTRY_BLOCK_PTR
7941 && e->dest != EXIT_BLOCK_PTR
7942 && (e->src->index + 1 != e->dest->index
7943 || !can_fallthru (e->src, e->dest)))
7946 "verify_flow_info: Incorrect fallthru edge %i->%i\n",
7947 e->src->index, e->dest->index);
7955 "verify_flow_info: Basic block %d succ edge is corrupted\n",
7957 fprintf (stderr, "Predecessor: ");
7958 dump_edge_info (stderr, e, 0);
7959 fprintf (stderr, "\nSuccessor: ");
7960 dump_edge_info (stderr, e, 1);
7964 if (e->dest != EXIT_BLOCK_PTR)
7966 edge e2 = e->dest->pred;
7967 while (e2 && e2 != e)
7971 error ("Basic block %i edge lists are corrupted", bb->index);
7983 error ("Basic block %d pred edge is corrupted", bb->index);
7984 fputs ("Predecessor: ", stderr);
7985 dump_edge_info (stderr, e, 0);
7986 fputs ("\nSuccessor: ", stderr);
7987 dump_edge_info (stderr, e, 1);
7988 fputc ('\n', stderr);
7991 if (e->src != ENTRY_BLOCK_PTR)
7993 edge e2 = e->src->succ;
7994 while (e2 && e2 != e)
7998 error ("Basic block %i edge lists are corrupted", bb->index);
8005 /* OK pointers are correct. Now check the header of basic
8006 block. It ought to contain optional CODE_LABEL followed
8007 by NOTE_BASIC_BLOCK. */
8009 if (GET_CODE (x) == CODE_LABEL)
8013 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
8019 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
8021 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d\n",
8028 /* Do checks for empty blocks here */
8035 if (NOTE_INSN_BASIC_BLOCK_P (x))
8037 error ("NOTE_INSN_BASIC_BLOCK %d in the middle of basic block %d",
8038 INSN_UID (x), bb->index);
8045 if (GET_CODE (x) == JUMP_INSN
8046 || GET_CODE (x) == CODE_LABEL
8047 || GET_CODE (x) == BARRIER)
8049 error ("In basic block %d:", bb->index);
8050 fatal_insn ("Flow control insn inside a basic block", x);
8058 last_bb_num_seen = -1;
8063 if (NOTE_INSN_BASIC_BLOCK_P (x))
8065 basic_block bb = NOTE_BASIC_BLOCK (x);
8067 if (bb->index != last_bb_num_seen + 1)
8068 /* Basic blocks not numbered consecutively. */
8071 last_bb_num_seen = bb->index;
8074 if (!bb_info[INSN_UID (x)])
8076 switch (GET_CODE (x))
8083 /* An addr_vec is placed outside any block block. */
8085 && GET_CODE (NEXT_INSN (x)) == JUMP_INSN
8086 && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
8087 || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
8092 /* But in any case, non-deletable labels can appear anywhere. */
8096 fatal_insn ("Insn outside basic block", x);
8101 && GET_CODE (x) == JUMP_INSN
8102 && returnjump_p (x) && ! condjump_p (x)
8103 && ! (NEXT_INSN (x) && GET_CODE (NEXT_INSN (x)) == BARRIER))
8104 fatal_insn ("Return not followed by barrier", x);
8109 if (num_bb_notes != n_basic_blocks)
8111 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
8112 num_bb_notes, n_basic_blocks);
8121 /* Functions to access an edge list with a vector representation.
8122 Enough data is kept such that given an index number, the
8123 pred and succ that edge represents can be determined, or
8124 given a pred and a succ, its index number can be returned.
8125 This allows algorithms which consume a lot of memory to
8126 represent the normally full matrix of edge (pred,succ) with a
8127 single indexed vector, edge (EDGE_INDEX (pred, succ)), with no
8128 wasted space in the client code due to sparse flow graphs. */
8130 /* This functions initializes the edge list. Basically the entire
8131 flowgraph is processed, and all edges are assigned a number,
8132 and the data structure is filled in. */
8137 struct edge_list *elist;
8143 block_count = n_basic_blocks + 2; /* Include the entry and exit blocks. */
8147 /* Determine the number of edges in the flow graph by counting successor
8148 edges on each basic block. */
8149 for (x = 0; x < n_basic_blocks; x++)
8151 basic_block bb = BASIC_BLOCK (x);
8153 for (e = bb->succ; e; e = e->succ_next)
8156 /* Don't forget successors of the entry block. */
8157 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
8160 elist = (struct edge_list *) xmalloc (sizeof (struct edge_list));
8161 elist->num_blocks = block_count;
8162 elist->num_edges = num_edges;
8163 elist->index_to_edge = (edge *) xmalloc (sizeof (edge) * num_edges);
8167 /* Follow successors of the entry block, and register these edges. */
8168 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
8170 elist->index_to_edge[num_edges] = e;
8174 for (x = 0; x < n_basic_blocks; x++)
8176 basic_block bb = BASIC_BLOCK (x);
8178 /* Follow all successors of blocks, and register these edges. */
8179 for (e = bb->succ; e; e = e->succ_next)
8181 elist->index_to_edge[num_edges] = e;
8188 /* This function free's memory associated with an edge list. */
8191 free_edge_list (elist)
8192 struct edge_list *elist;
8196 free (elist->index_to_edge);
8201 /* This function provides debug output showing an edge list. */
8204 print_edge_list (f, elist)
8206 struct edge_list *elist;
8209 fprintf (f, "Compressed edge list, %d BBs + entry & exit, and %d edges\n",
8210 elist->num_blocks - 2, elist->num_edges);
8212 for (x = 0; x < elist->num_edges; x++)
8214 fprintf (f, " %-4d - edge(", x);
8215 if (INDEX_EDGE_PRED_BB (elist, x) == ENTRY_BLOCK_PTR)
8216 fprintf (f, "entry,");
8218 fprintf (f, "%d,", INDEX_EDGE_PRED_BB (elist, x)->index);
8220 if (INDEX_EDGE_SUCC_BB (elist, x) == EXIT_BLOCK_PTR)
8221 fprintf (f, "exit)\n");
8223 fprintf (f, "%d)\n", INDEX_EDGE_SUCC_BB (elist, x)->index);
8227 /* This function provides an internal consistency check of an edge list,
8228 verifying that all edges are present, and that there are no
8232 verify_edge_list (f, elist)
8234 struct edge_list *elist;
8236 int x, pred, succ, index;
8239 for (x = 0; x < n_basic_blocks; x++)
8241 basic_block bb = BASIC_BLOCK (x);
8243 for (e = bb->succ; e; e = e->succ_next)
8245 pred = e->src->index;
8246 succ = e->dest->index;
8247 index = EDGE_INDEX (elist, e->src, e->dest);
8248 if (index == EDGE_INDEX_NO_EDGE)
8250 fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
8253 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
8254 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
8255 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
8256 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
8257 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
8258 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
8261 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
8263 pred = e->src->index;
8264 succ = e->dest->index;
8265 index = EDGE_INDEX (elist, e->src, e->dest);
8266 if (index == EDGE_INDEX_NO_EDGE)
8268 fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
8271 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
8272 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
8273 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
8274 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
8275 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
8276 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
8278 /* We've verified that all the edges are in the list, no lets make sure
8279 there are no spurious edges in the list. */
8281 for (pred = 0; pred < n_basic_blocks; pred++)
8282 for (succ = 0; succ < n_basic_blocks; succ++)
8284 basic_block p = BASIC_BLOCK (pred);
8285 basic_block s = BASIC_BLOCK (succ);
8289 for (e = p->succ; e; e = e->succ_next)
8295 for (e = s->pred; e; e = e->pred_next)
8301 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
8302 == EDGE_INDEX_NO_EDGE && found_edge != 0)
8303 fprintf (f, "*** Edge (%d, %d) appears to not have an index\n",
8305 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
8306 != EDGE_INDEX_NO_EDGE && found_edge == 0)
8307 fprintf (f, "*** Edge (%d, %d) has index %d, but there is no edge\n",
8308 pred, succ, EDGE_INDEX (elist, BASIC_BLOCK (pred),
8309 BASIC_BLOCK (succ)));
8311 for (succ = 0; succ < n_basic_blocks; succ++)
8313 basic_block p = ENTRY_BLOCK_PTR;
8314 basic_block s = BASIC_BLOCK (succ);
8318 for (e = p->succ; e; e = e->succ_next)
8324 for (e = s->pred; e; e = e->pred_next)
8330 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
8331 == EDGE_INDEX_NO_EDGE && found_edge != 0)
8332 fprintf (f, "*** Edge (entry, %d) appears to not have an index\n",
8334 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
8335 != EDGE_INDEX_NO_EDGE && found_edge == 0)
8336 fprintf (f, "*** Edge (entry, %d) has index %d, but no edge exists\n",
8337 succ, EDGE_INDEX (elist, ENTRY_BLOCK_PTR,
8338 BASIC_BLOCK (succ)));
8340 for (pred = 0; pred < n_basic_blocks; pred++)
8342 basic_block p = BASIC_BLOCK (pred);
8343 basic_block s = EXIT_BLOCK_PTR;
8347 for (e = p->succ; e; e = e->succ_next)
8353 for (e = s->pred; e; e = e->pred_next)
8359 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
8360 == EDGE_INDEX_NO_EDGE && found_edge != 0)
8361 fprintf (f, "*** Edge (%d, exit) appears to not have an index\n",
8363 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
8364 != EDGE_INDEX_NO_EDGE && found_edge == 0)
8365 fprintf (f, "*** Edge (%d, exit) has index %d, but no edge exists\n",
8366 pred, EDGE_INDEX (elist, BASIC_BLOCK (pred),
8371 /* This routine will determine what, if any, edge there is between
8372 a specified predecessor and successor. */
8375 find_edge_index (edge_list, pred, succ)
8376 struct edge_list *edge_list;
8377 basic_block pred, succ;
8380 for (x = 0; x < NUM_EDGES (edge_list); x++)
8382 if (INDEX_EDGE_PRED_BB (edge_list, x) == pred
8383 && INDEX_EDGE_SUCC_BB (edge_list, x) == succ)
8386 return (EDGE_INDEX_NO_EDGE);
8389 /* This function will remove an edge from the flow graph. */
8395 edge last_pred = NULL;
8396 edge last_succ = NULL;
8398 basic_block src, dest;
8401 for (tmp = src->succ; tmp && tmp != e; tmp = tmp->succ_next)
8407 last_succ->succ_next = e->succ_next;
8409 src->succ = e->succ_next;
8411 for (tmp = dest->pred; tmp && tmp != e; tmp = tmp->pred_next)
8417 last_pred->pred_next = e->pred_next;
8419 dest->pred = e->pred_next;
8425 /* This routine will remove any fake successor edges for a basic block.
8426 When the edge is removed, it is also removed from whatever predecessor
8430 remove_fake_successors (bb)
8434 for (e = bb->succ; e;)
8438 if ((tmp->flags & EDGE_FAKE) == EDGE_FAKE)
8443 /* This routine will remove all fake edges from the flow graph. If
8444 we remove all fake successors, it will automatically remove all
8445 fake predecessors. */
8448 remove_fake_edges ()
8452 for (x = 0; x < n_basic_blocks; x++)
8453 remove_fake_successors (BASIC_BLOCK (x));
8455 /* We've handled all successors except the entry block's. */
8456 remove_fake_successors (ENTRY_BLOCK_PTR);
8459 /* This function will add a fake edge between any block which has no
8460 successors, and the exit block. Some data flow equations require these
8464 add_noreturn_fake_exit_edges ()
8468 for (x = 0; x < n_basic_blocks; x++)
8469 if (BASIC_BLOCK (x)->succ == NULL)
8470 make_edge (NULL, BASIC_BLOCK (x), EXIT_BLOCK_PTR, EDGE_FAKE);
8473 /* This function adds a fake edge between any infinite loops to the
8474 exit block. Some optimizations require a path from each node to
8477 See also Morgan, Figure 3.10, pp. 82-83.
8479 The current implementation is ugly, not attempting to minimize the
8480 number of inserted fake edges. To reduce the number of fake edges
8481 to insert, add fake edges from _innermost_ loops containing only
8482 nodes not reachable from the exit block. */
8485 connect_infinite_loops_to_exit ()
8487 basic_block unvisited_block;
8489 /* Perform depth-first search in the reverse graph to find nodes
8490 reachable from the exit block. */
8491 struct depth_first_search_dsS dfs_ds;
8493 flow_dfs_compute_reverse_init (&dfs_ds);
8494 flow_dfs_compute_reverse_add_bb (&dfs_ds, EXIT_BLOCK_PTR);
8496 /* Repeatedly add fake edges, updating the unreachable nodes. */
8499 unvisited_block = flow_dfs_compute_reverse_execute (&dfs_ds);
8500 if (!unvisited_block)
8502 make_edge (NULL, unvisited_block, EXIT_BLOCK_PTR, EDGE_FAKE);
8503 flow_dfs_compute_reverse_add_bb (&dfs_ds, unvisited_block);
8506 flow_dfs_compute_reverse_finish (&dfs_ds);
8511 /* Redirect an edge's successor from one block to another. */
8514 redirect_edge_succ (e, new_succ)
8516 basic_block new_succ;
8520 /* Disconnect the edge from the old successor block. */
8521 for (pe = &e->dest->pred; *pe != e; pe = &(*pe)->pred_next)
8523 *pe = (*pe)->pred_next;
8525 /* Reconnect the edge to the new successor block. */
8526 e->pred_next = new_succ->pred;
8531 /* Redirect an edge's predecessor from one block to another. */
8534 redirect_edge_pred (e, new_pred)
8536 basic_block new_pred;
8540 /* Disconnect the edge from the old predecessor block. */
8541 for (pe = &e->src->succ; *pe != e; pe = &(*pe)->succ_next)
8543 *pe = (*pe)->succ_next;
8545 /* Reconnect the edge to the new predecessor block. */
8546 e->succ_next = new_pred->succ;
8551 /* Dump the list of basic blocks in the bitmap NODES. */
8554 flow_nodes_print (str, nodes, file)
8556 const sbitmap nodes;
8564 fprintf (file, "%s { ", str);
8565 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {fprintf (file, "%d ", node);});
8566 fputs ("}\n", file);
8570 /* Dump the list of edges in the array EDGE_LIST. */
8573 flow_edge_list_print (str, edge_list, num_edges, file)
8575 const edge *edge_list;
8584 fprintf (file, "%s { ", str);
8585 for (i = 0; i < num_edges; i++)
8586 fprintf (file, "%d->%d ", edge_list[i]->src->index,
8587 edge_list[i]->dest->index);
8588 fputs ("}\n", file);
8592 /* Dump loop related CFG information. */
8595 flow_loops_cfg_dump (loops, file)
8596 const struct loops *loops;
8601 if (! loops->num || ! file || ! loops->cfg.dom)
8604 for (i = 0; i < n_basic_blocks; i++)
8608 fprintf (file, ";; %d succs { ", i);
8609 for (succ = BASIC_BLOCK (i)->succ; succ; succ = succ->succ_next)
8610 fprintf (file, "%d ", succ->dest->index);
8611 flow_nodes_print ("} dom", loops->cfg.dom[i], file);
8614 /* Dump the DFS node order. */
8615 if (loops->cfg.dfs_order)
8617 fputs (";; DFS order: ", file);
8618 for (i = 0; i < n_basic_blocks; i++)
8619 fprintf (file, "%d ", loops->cfg.dfs_order[i]);
8622 /* Dump the reverse completion node order. */
8623 if (loops->cfg.rc_order)
8625 fputs (";; RC order: ", file);
8626 for (i = 0; i < n_basic_blocks; i++)
8627 fprintf (file, "%d ", loops->cfg.rc_order[i]);
8632 /* Return non-zero if the nodes of LOOP are a subset of OUTER. */
8635 flow_loop_nested_p (outer, loop)
8639 return sbitmap_a_subset_b_p (loop->nodes, outer->nodes);
8643 /* Dump the loop information specified by LOOP to the stream FILE
8644 using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
8646 flow_loop_dump (loop, file, loop_dump_aux, verbose)
8647 const struct loop *loop;
8649 void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
8652 if (! loop || ! loop->header)
8655 fprintf (file, ";;\n;; Loop %d (%d to %d):%s%s\n",
8656 loop->num, INSN_UID (loop->first->head),
8657 INSN_UID (loop->last->end),
8658 loop->shared ? " shared" : "",
8659 loop->invalid ? " invalid" : "");
8660 fprintf (file, ";; header %d, latch %d, pre-header %d, first %d, last %d\n",
8661 loop->header->index, loop->latch->index,
8662 loop->pre_header ? loop->pre_header->index : -1,
8663 loop->first->index, loop->last->index);
8664 fprintf (file, ";; depth %d, level %d, outer %ld\n",
8665 loop->depth, loop->level,
8666 (long) (loop->outer ? loop->outer->num : -1));
8668 if (loop->pre_header_edges)
8669 flow_edge_list_print (";; pre-header edges", loop->pre_header_edges,
8670 loop->num_pre_header_edges, file);
8671 flow_edge_list_print (";; entry edges", loop->entry_edges,
8672 loop->num_entries, file);
8673 fprintf (file, ";; %d", loop->num_nodes);
8674 flow_nodes_print (" nodes", loop->nodes, file);
8675 flow_edge_list_print (";; exit edges", loop->exit_edges,
8676 loop->num_exits, file);
8677 if (loop->exits_doms)
8678 flow_nodes_print (";; exit doms", loop->exits_doms, file);
8680 loop_dump_aux (loop, file, verbose);
8684 /* Dump the loop information specified by LOOPS to the stream FILE,
8685 using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
8687 flow_loops_dump (loops, file, loop_dump_aux, verbose)
8688 const struct loops *loops;
8690 void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
8696 num_loops = loops->num;
8697 if (! num_loops || ! file)
8700 fprintf (file, ";; %d loops found, %d levels\n",
8701 num_loops, loops->levels);
8703 for (i = 0; i < num_loops; i++)
8705 struct loop *loop = &loops->array[i];
8707 flow_loop_dump (loop, file, loop_dump_aux, verbose);
8713 for (j = 0; j < i; j++)
8715 struct loop *oloop = &loops->array[j];
8717 if (loop->header == oloop->header)
8722 smaller = loop->num_nodes < oloop->num_nodes;
8724 /* If the union of LOOP and OLOOP is different than
8725 the larger of LOOP and OLOOP then LOOP and OLOOP
8726 must be disjoint. */
8727 disjoint = ! flow_loop_nested_p (smaller ? loop : oloop,
8728 smaller ? oloop : loop);
8730 ";; loop header %d shared by loops %d, %d %s\n",
8731 loop->header->index, i, j,
8732 disjoint ? "disjoint" : "nested");
8739 flow_loops_cfg_dump (loops, file);
8743 /* Free all the memory allocated for LOOPS. */
8746 flow_loops_free (loops)
8747 struct loops *loops;
8756 /* Free the loop descriptors. */
8757 for (i = 0; i < loops->num; i++)
8759 struct loop *loop = &loops->array[i];
8761 if (loop->pre_header_edges)
8762 free (loop->pre_header_edges);
8764 sbitmap_free (loop->nodes);
8765 if (loop->entry_edges)
8766 free (loop->entry_edges);
8767 if (loop->exit_edges)
8768 free (loop->exit_edges);
8769 if (loop->exits_doms)
8770 sbitmap_free (loop->exits_doms);
8772 free (loops->array);
8773 loops->array = NULL;
8776 sbitmap_vector_free (loops->cfg.dom);
8777 if (loops->cfg.dfs_order)
8778 free (loops->cfg.dfs_order);
8780 if (loops->shared_headers)
8781 sbitmap_free (loops->shared_headers);
8786 /* Find the entry edges into the loop with header HEADER and nodes
8787 NODES and store in ENTRY_EDGES array. Return the number of entry
8788 edges from the loop. */
8791 flow_loop_entry_edges_find (header, nodes, entry_edges)
8793 const sbitmap nodes;
8799 *entry_edges = NULL;
8802 for (e = header->pred; e; e = e->pred_next)
8804 basic_block src = e->src;
8806 if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
8813 *entry_edges = (edge *) xmalloc (num_entries * sizeof (edge *));
8816 for (e = header->pred; e; e = e->pred_next)
8818 basic_block src = e->src;
8820 if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
8821 (*entry_edges)[num_entries++] = e;
8828 /* Find the exit edges from the loop using the bitmap of loop nodes
8829 NODES and store in EXIT_EDGES array. Return the number of
8830 exit edges from the loop. */
8833 flow_loop_exit_edges_find (nodes, exit_edges)
8834 const sbitmap nodes;
8843 /* Check all nodes within the loop to see if there are any
8844 successors not in the loop. Note that a node may have multiple
8845 exiting edges ????? A node can have one jumping edge and one fallthru
8846 edge so only one of these can exit the loop. */
8848 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
8849 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
8851 basic_block dest = e->dest;
8853 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
8861 *exit_edges = (edge *) xmalloc (num_exits * sizeof (edge *));
8863 /* Store all exiting edges into an array. */
8865 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
8866 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
8868 basic_block dest = e->dest;
8870 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
8871 (*exit_edges)[num_exits++] = e;
8879 /* Find the nodes contained within the loop with header HEADER and
8880 latch LATCH and store in NODES. Return the number of nodes within
8884 flow_loop_nodes_find (header, latch, nodes)
8893 stack = (basic_block *) xmalloc (n_basic_blocks * sizeof (basic_block));
8896 /* Start with only the loop header in the set of loop nodes. */
8897 sbitmap_zero (nodes);
8898 SET_BIT (nodes, header->index);
8900 header->loop_depth++;
8902 /* Push the loop latch on to the stack. */
8903 if (! TEST_BIT (nodes, latch->index))
8905 SET_BIT (nodes, latch->index);
8906 latch->loop_depth++;
8908 stack[sp++] = latch;
8917 for (e = node->pred; e; e = e->pred_next)
8919 basic_block ancestor = e->src;
8921 /* If each ancestor not marked as part of loop, add to set of
8922 loop nodes and push on to stack. */
8923 if (ancestor != ENTRY_BLOCK_PTR
8924 && ! TEST_BIT (nodes, ancestor->index))
8926 SET_BIT (nodes, ancestor->index);
8927 ancestor->loop_depth++;
8929 stack[sp++] = ancestor;
8937 /* Compute the depth first search order and store in the array
8938 DFS_ORDER if non-zero, marking the nodes visited in VISITED. If
8939 RC_ORDER is non-zero, return the reverse completion number for each
8940 node. Returns the number of nodes visited. A depth first search
8941 tries to get as far away from the starting point as quickly as
8945 flow_depth_first_order_compute (dfs_order, rc_order)
8952 int rcnum = n_basic_blocks - 1;
8955 /* Allocate stack for back-tracking up CFG. */
8956 stack = (edge *) xmalloc ((n_basic_blocks + 1) * sizeof (edge));
8959 /* Allocate bitmap to track nodes that have been visited. */
8960 visited = sbitmap_alloc (n_basic_blocks);
8962 /* None of the nodes in the CFG have been visited yet. */
8963 sbitmap_zero (visited);
8965 /* Push the first edge on to the stack. */
8966 stack[sp++] = ENTRY_BLOCK_PTR->succ;
8974 /* Look at the edge on the top of the stack. */
8979 /* Check if the edge destination has been visited yet. */
8980 if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index))
8982 /* Mark that we have visited the destination. */
8983 SET_BIT (visited, dest->index);
8986 dfs_order[dfsnum++] = dest->index;
8990 /* Since the DEST node has been visited for the first
8991 time, check its successors. */
8992 stack[sp++] = dest->succ;
8996 /* There are no successors for the DEST node so assign
8997 its reverse completion number. */
8999 rc_order[rcnum--] = dest->index;
9004 if (! e->succ_next && src != ENTRY_BLOCK_PTR)
9006 /* There are no more successors for the SRC node
9007 so assign its reverse completion number. */
9009 rc_order[rcnum--] = src->index;
9013 stack[sp - 1] = e->succ_next;
9020 sbitmap_free (visited);
9022 /* The number of nodes visited should not be greater than
9024 if (dfsnum > n_basic_blocks)
9027 /* There are some nodes left in the CFG that are unreachable. */
9028 if (dfsnum < n_basic_blocks)
9033 /* Compute the depth first search order on the _reverse_ graph and
9034 store in the array DFS_ORDER, marking the nodes visited in VISITED.
9035 Returns the number of nodes visited.
9037 The computation is split into three pieces:
9039 flow_dfs_compute_reverse_init () creates the necessary data
9042 flow_dfs_compute_reverse_add_bb () adds a basic block to the data
9043 structures. The block will start the search.
9045 flow_dfs_compute_reverse_execute () continues (or starts) the
9046 search using the block on the top of the stack, stopping when the
9049 flow_dfs_compute_reverse_finish () destroys the necessary data
9052 Thus, the user will probably call ..._init(), call ..._add_bb() to
9053 add a beginning basic block to the stack, call ..._execute(),
9054 possibly add another bb to the stack and again call ..._execute(),
9055 ..., and finally call _finish(). */
9057 /* Initialize the data structures used for depth-first search on the
9058 reverse graph. If INITIALIZE_STACK is nonzero, the exit block is
9059 added to the basic block stack. DATA is the current depth-first
9060 search context. If INITIALIZE_STACK is non-zero, there is an
9061 element on the stack. */
9064 flow_dfs_compute_reverse_init (data)
9065 depth_first_search_ds data;
9067 /* Allocate stack for back-tracking up CFG. */
9069 (basic_block *) xmalloc ((n_basic_blocks - (INVALID_BLOCK + 1))
9070 * sizeof (basic_block));
9073 /* Allocate bitmap to track nodes that have been visited. */
9074 data->visited_blocks = sbitmap_alloc (n_basic_blocks - (INVALID_BLOCK + 1));
9076 /* None of the nodes in the CFG have been visited yet. */
9077 sbitmap_zero (data->visited_blocks);
9082 /* Add the specified basic block to the top of the dfs data
9083 structures. When the search continues, it will start at the
9087 flow_dfs_compute_reverse_add_bb (data, bb)
9088 depth_first_search_ds data;
9091 data->stack[data->sp++] = bb;
9095 /* Continue the depth-first search through the reverse graph starting
9096 with the block at the stack's top and ending when the stack is
9097 empty. Visited nodes are marked. Returns an unvisited basic
9098 block, or NULL if there is none available. */
9101 flow_dfs_compute_reverse_execute (data)
9102 depth_first_search_ds data;
9108 while (data->sp > 0)
9110 bb = data->stack[--data->sp];
9112 /* Mark that we have visited this node. */
9113 if (!TEST_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1)))
9115 SET_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1));
9117 /* Perform depth-first search on adjacent vertices. */
9118 for (e = bb->pred; e; e = e->pred_next)
9119 flow_dfs_compute_reverse_add_bb (data, e->src);
9123 /* Determine if there are unvisited basic blocks. */
9124 for (i = n_basic_blocks - (INVALID_BLOCK + 1); --i >= 0;)
9125 if (!TEST_BIT (data->visited_blocks, i))
9126 return BASIC_BLOCK (i + (INVALID_BLOCK + 1));
9130 /* Destroy the data structures needed for depth-first search on the
9134 flow_dfs_compute_reverse_finish (data)
9135 depth_first_search_ds data;
9138 sbitmap_free (data->visited_blocks);
9143 /* Find the root node of the loop pre-header extended basic block and
9144 the edges along the trace from the root node to the loop header. */
9147 flow_loop_pre_header_scan (loop)
9153 loop->num_pre_header_edges = 0;
9155 if (loop->num_entries != 1)
9158 ebb = loop->entry_edges[0]->src;
9160 if (ebb != ENTRY_BLOCK_PTR)
9164 /* Count number of edges along trace from loop header to
9165 root of pre-header extended basic block. Usually this is
9166 only one or two edges. */
9168 while (ebb->pred->src != ENTRY_BLOCK_PTR && ! ebb->pred->pred_next)
9170 ebb = ebb->pred->src;
9174 loop->pre_header_edges = (edge *) xmalloc (num * sizeof (edge *));
9175 loop->num_pre_header_edges = num;
9177 /* Store edges in order that they are followed. The source
9178 of the first edge is the root node of the pre-header extended
9179 basic block and the destination of the last last edge is
9181 for (e = loop->entry_edges[0]; num; e = e->src->pred)
9183 loop->pre_header_edges[--num] = e;
9189 /* Return the block for the pre-header of the loop with header
9190 HEADER where DOM specifies the dominator information. Return NULL if
9191 there is no pre-header. */
9194 flow_loop_pre_header_find (header, dom)
9198 basic_block pre_header;
9201 /* If block p is a predecessor of the header and is the only block
9202 that the header does not dominate, then it is the pre-header. */
9204 for (e = header->pred; e; e = e->pred_next)
9206 basic_block node = e->src;
9208 if (node != ENTRY_BLOCK_PTR
9209 && ! TEST_BIT (dom[node->index], header->index))
9211 if (pre_header == NULL)
9215 /* There are multiple edges into the header from outside
9216 the loop so there is no pre-header block. */
9225 /* Add LOOP to the loop hierarchy tree where PREVLOOP was the loop
9226 previously added. The insertion algorithm assumes that the loops
9227 are added in the order found by a depth first search of the CFG. */
9230 flow_loop_tree_node_add (prevloop, loop)
9231 struct loop *prevloop;
9235 if (flow_loop_nested_p (prevloop, loop))
9237 prevloop->inner = loop;
9238 loop->outer = prevloop;
9242 while (prevloop->outer)
9244 if (flow_loop_nested_p (prevloop->outer, loop))
9246 prevloop->next = loop;
9247 loop->outer = prevloop->outer;
9250 prevloop = prevloop->outer;
9253 prevloop->next = loop;
9257 /* Build the loop hierarchy tree for LOOPS. */
9260 flow_loops_tree_build (loops)
9261 struct loops *loops;
9266 num_loops = loops->num;
9270 /* Root the loop hierarchy tree with the first loop found.
9271 Since we used a depth first search this should be the
9273 loops->tree_root = &loops->array[0];
9274 loops->tree_root->outer = loops->tree_root->inner = loops->tree_root->next = NULL;
9276 /* Add the remaining loops to the tree. */
9277 for (i = 1; i < num_loops; i++)
9278 flow_loop_tree_node_add (&loops->array[i - 1], &loops->array[i]);
9281 /* Helper function to compute loop nesting depth and enclosed loop level
9282 for the natural loop specified by LOOP at the loop depth DEPTH.
9283 Returns the loop level. */
9286 flow_loop_level_compute (loop, depth)
9296 /* Traverse loop tree assigning depth and computing level as the
9297 maximum level of all the inner loops of this loop. The loop
9298 level is equivalent to the height of the loop in the loop tree
9299 and corresponds to the number of enclosed loop levels (including
9301 for (inner = loop->inner; inner; inner = inner->next)
9305 ilevel = flow_loop_level_compute (inner, depth + 1) + 1;
9310 loop->level = level;
9311 loop->depth = depth;
9315 /* Compute the loop nesting depth and enclosed loop level for the loop
9316 hierarchy tree specfied by LOOPS. Return the maximum enclosed loop
9320 flow_loops_level_compute (loops)
9321 struct loops *loops;
9327 /* Traverse all the outer level loops. */
9328 for (loop = loops->tree_root; loop; loop = loop->next)
9330 level = flow_loop_level_compute (loop, 1);
9338 /* Scan a single natural loop specified by LOOP collecting information
9339 about it specified by FLAGS. */
9342 flow_loop_scan (loops, loop, flags)
9343 struct loops *loops;
9347 /* Determine prerequisites. */
9348 if ((flags & LOOP_EXITS_DOMS) && ! loop->exit_edges)
9349 flags |= LOOP_EXIT_EDGES;
9351 if (flags & LOOP_ENTRY_EDGES)
9353 /* Find edges which enter the loop header.
9354 Note that the entry edges should only
9355 enter the header of a natural loop. */
9357 = flow_loop_entry_edges_find (loop->header,
9359 &loop->entry_edges);
9362 if (flags & LOOP_EXIT_EDGES)
9364 /* Find edges which exit the loop. */
9366 = flow_loop_exit_edges_find (loop->nodes,
9370 if (flags & LOOP_EXITS_DOMS)
9374 /* Determine which loop nodes dominate all the exits
9376 loop->exits_doms = sbitmap_alloc (n_basic_blocks);
9377 sbitmap_copy (loop->exits_doms, loop->nodes);
9378 for (j = 0; j < loop->num_exits; j++)
9379 sbitmap_a_and_b (loop->exits_doms, loop->exits_doms,
9380 loops->cfg.dom[loop->exit_edges[j]->src->index]);
9382 /* The header of a natural loop must dominate
9384 if (! TEST_BIT (loop->exits_doms, loop->header->index))
9388 if (flags & LOOP_PRE_HEADER)
9390 /* Look to see if the loop has a pre-header node. */
9392 = flow_loop_pre_header_find (loop->header, loops->cfg.dom);
9394 /* Find the blocks within the extended basic block of
9395 the loop pre-header. */
9396 flow_loop_pre_header_scan (loop);
9402 /* Find all the natural loops in the function and save in LOOPS structure
9403 and recalculate loop_depth information in basic block structures.
9404 FLAGS controls which loop information is collected.
9405 Return the number of natural loops found. */
9408 flow_loops_find (loops, flags)
9409 struct loops *loops;
9421 /* This function cannot be repeatedly called with different
9422 flags to build up the loop information. The loop tree
9423 must always be built if this function is called. */
9424 if (! (flags & LOOP_TREE))
9427 memset (loops, 0, sizeof (*loops));
9429 /* Taking care of this degenerate case makes the rest of
9430 this code simpler. */
9431 if (n_basic_blocks == 0)
9437 /* Compute the dominators. */
9438 dom = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
9439 calculate_dominance_info (NULL, dom, CDI_DOMINATORS);
9441 /* Count the number of loop edges (back edges). This should be the
9442 same as the number of natural loops. */
9445 for (b = 0; b < n_basic_blocks; b++)
9449 header = BASIC_BLOCK (b);
9450 header->loop_depth = 0;
9452 for (e = header->pred; e; e = e->pred_next)
9454 basic_block latch = e->src;
9456 /* Look for back edges where a predecessor is dominated
9457 by this block. A natural loop has a single entry
9458 node (header) that dominates all the nodes in the
9459 loop. It also has single back edge to the header
9460 from a latch node. Note that multiple natural loops
9461 may share the same header. */
9462 if (b != header->index)
9465 if (latch != ENTRY_BLOCK_PTR && TEST_BIT (dom[latch->index], b))
9472 /* Compute depth first search order of the CFG so that outer
9473 natural loops will be found before inner natural loops. */
9474 dfs_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
9475 rc_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
9476 flow_depth_first_order_compute (dfs_order, rc_order);
9478 /* Save CFG derived information to avoid recomputing it. */
9479 loops->cfg.dom = dom;
9480 loops->cfg.dfs_order = dfs_order;
9481 loops->cfg.rc_order = rc_order;
9483 /* Allocate loop structures. */
9485 = (struct loop *) xcalloc (num_loops, sizeof (struct loop));
9487 headers = sbitmap_alloc (n_basic_blocks);
9488 sbitmap_zero (headers);
9490 loops->shared_headers = sbitmap_alloc (n_basic_blocks);
9491 sbitmap_zero (loops->shared_headers);
9493 /* Find and record information about all the natural loops
9496 for (b = 0; b < n_basic_blocks; b++)
9500 /* Search the nodes of the CFG in reverse completion order
9501 so that we can find outer loops first. */
9502 header = BASIC_BLOCK (rc_order[b]);
9504 /* Look for all the possible latch blocks for this header. */
9505 for (e = header->pred; e; e = e->pred_next)
9507 basic_block latch = e->src;
9509 /* Look for back edges where a predecessor is dominated
9510 by this block. A natural loop has a single entry
9511 node (header) that dominates all the nodes in the
9512 loop. It also has single back edge to the header
9513 from a latch node. Note that multiple natural loops
9514 may share the same header. */
9515 if (latch != ENTRY_BLOCK_PTR
9516 && TEST_BIT (dom[latch->index], header->index))
9520 loop = loops->array + num_loops;
9522 loop->header = header;
9523 loop->latch = latch;
9524 loop->num = num_loops;
9531 for (i = 0; i < num_loops; i++)
9533 struct loop *loop = &loops->array[i];
9535 /* Keep track of blocks that are loop headers so
9536 that we can tell which loops should be merged. */
9537 if (TEST_BIT (headers, loop->header->index))
9538 SET_BIT (loops->shared_headers, loop->header->index);
9539 SET_BIT (headers, loop->header->index);
9541 /* Find nodes contained within the loop. */
9542 loop->nodes = sbitmap_alloc (n_basic_blocks);
9544 = flow_loop_nodes_find (loop->header, loop->latch, loop->nodes);
9546 /* Compute first and last blocks within the loop.
9547 These are often the same as the loop header and
9548 loop latch respectively, but this is not always
9551 = BASIC_BLOCK (sbitmap_first_set_bit (loop->nodes));
9553 = BASIC_BLOCK (sbitmap_last_set_bit (loop->nodes));
9555 flow_loop_scan (loops, loop, flags);
9558 /* Natural loops with shared headers may either be disjoint or
9559 nested. Disjoint loops with shared headers cannot be inner
9560 loops and should be merged. For now just mark loops that share
9562 for (i = 0; i < num_loops; i++)
9563 if (TEST_BIT (loops->shared_headers, loops->array[i].header->index))
9564 loops->array[i].shared = 1;
9566 sbitmap_free (headers);
9570 sbitmap_vector_free (dom);
9573 loops->num = num_loops;
9575 /* Build the loop hierarchy tree. */
9576 flow_loops_tree_build (loops);
9578 /* Assign the loop nesting depth and enclosed loop level for each
9580 loops->levels = flow_loops_level_compute (loops);
9586 /* Update the information regarding the loops in the CFG
9587 specified by LOOPS. */
9589 flow_loops_update (loops, flags)
9590 struct loops *loops;
9593 /* One day we may want to update the current loop data. For now
9594 throw away the old stuff and rebuild what we need. */
9596 flow_loops_free (loops);
9598 return flow_loops_find (loops, flags);
9602 /* Return non-zero if edge E enters header of LOOP from outside of LOOP. */
9605 flow_loop_outside_edge_p (loop, e)
9606 const struct loop *loop;
9609 if (e->dest != loop->header)
9611 return (e->src == ENTRY_BLOCK_PTR)
9612 || ! TEST_BIT (loop->nodes, e->src->index);
9615 /* Clear LOG_LINKS fields of insns in a chain.
9616 Also clear the global_live_at_{start,end} fields of the basic block
9620 clear_log_links (insns)
9626 for (i = insns; i; i = NEXT_INSN (i))
9630 for (b = 0; b < n_basic_blocks; b++)
9632 basic_block bb = BASIC_BLOCK (b);
9634 bb->global_live_at_start = NULL;
9635 bb->global_live_at_end = NULL;
9638 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
9639 EXIT_BLOCK_PTR->global_live_at_start = NULL;
9642 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
9643 correspond to the hard registers, if any, set in that map. This
9644 could be done far more efficiently by having all sorts of special-cases
9645 with moving single words, but probably isn't worth the trouble. */
9648 reg_set_to_hard_reg_set (to, from)
9654 EXECUTE_IF_SET_IN_BITMAP
9657 if (i >= FIRST_PSEUDO_REGISTER)
9659 SET_HARD_REG_BIT (*to, i);
9663 /* Called once at intialization time. */
9668 static int initialized;
9672 gcc_obstack_init (&flow_obstack);
9673 flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);
9678 obstack_free (&flow_obstack, flow_firstobj);
9679 flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);