1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
22 /* This file contains the data flow analysis pass of the compiler. It
23 computes data flow information which tells combine_instructions
24 which insns to consider combining and controls register allocation.
26 Additional data flow information that is too bulky to record is
27 generated during the analysis, and is used at that time to create
28 autoincrement and autodecrement addressing.
30 The first step is dividing the function into basic blocks.
31 find_basic_blocks does this. Then life_analysis determines
32 where each register is live and where it is dead.
34 ** find_basic_blocks **
36 find_basic_blocks divides the current function's rtl into basic
37 blocks and constructs the CFG. The blocks are recorded in the
38 basic_block_info array; the CFG exists in the edge structures
39 referenced by the blocks.
41 find_basic_blocks also finds any unreachable loops and deletes them.
45 life_analysis is called immediately after find_basic_blocks.
46 It uses the basic block information to determine where each
47 hard or pseudo register is live.
49 ** live-register info **
51 The information about where each register is live is in two parts:
52 the REG_NOTES of insns, and the vector basic_block->global_live_at_start.
54 basic_block->global_live_at_start has an element for each basic
55 block, and the element is a bit-vector with a bit for each hard or
56 pseudo register. The bit is 1 if the register is live at the
57 beginning of the basic block.
59 Two types of elements can be added to an insn's REG_NOTES.
60 A REG_DEAD note is added to an insn's REG_NOTES for any register
61 that meets both of two conditions: The value in the register is not
62 needed in subsequent insns and the insn does not replace the value in
63 the register (in the case of multi-word hard registers, the value in
64 each register must be replaced by the insn to avoid a REG_DEAD note).
66 In the vast majority of cases, an object in a REG_DEAD note will be
67 used somewhere in the insn. The (rare) exception to this is if an
68 insn uses a multi-word hard register and only some of the registers are
69 needed in subsequent insns. In that case, REG_DEAD notes will be
70 provided for those hard registers that are not subsequently needed.
71 Partial REG_DEAD notes of this type do not occur when an insn sets
72 only some of the hard registers used in such a multi-word operand;
73 omitting REG_DEAD notes for objects stored in an insn is optional and
74 the desire to do so does not justify the complexity of the partial
77 REG_UNUSED notes are added for each register that is set by the insn
78 but is unused subsequently (if every register set by the insn is unused
79 and the insn does not reference memory or have some other side-effect,
80 the insn is deleted instead). If only part of a multi-word hard
81 register is used in a subsequent insn, REG_UNUSED notes are made for
82 the parts that will not be used.
84 To determine which registers are live after any insn, one can
85 start from the beginning of the basic block and scan insns, noting
86 which registers are set by each insn and which die there.
88 ** Other actions of life_analysis **
90 life_analysis sets up the LOG_LINKS fields of insns because the
91 information needed to do so is readily available.
93 life_analysis deletes insns whose only effect is to store a value
96 life_analysis notices cases where a reference to a register as
97 a memory address can be combined with a preceding or following
98 incrementation or decrementation of the register. The separate
99 instruction to increment or decrement is deleted and the address
100 is changed to a POST_INC or similar rtx.
102 Each time an incrementing or decrementing address is created,
103 a REG_INC element is added to the insn's REG_NOTES list.
105 life_analysis fills in certain vectors containing information about
106 register usage: REG_N_REFS, REG_N_DEATHS, REG_N_SETS, REG_LIVE_LENGTH,
107 REG_N_CALLS_CROSSED and REG_BASIC_BLOCK.
109 life_analysis sets current_function_sp_is_unchanging if the function
110 doesn't modify the stack pointer. */
114 Split out from life_analysis:
115 - local property discovery (bb->local_live, bb->local_set)
116 - global property computation
118 - pre/post modify transformation
126 #include "hard-reg-set.h"
127 #include "basic-block.h"
128 #include "insn-config.h"
132 #include "function.h"
136 #include "insn-flags.h"
141 #include "splay-tree.h"
143 #define obstack_chunk_alloc xmalloc
144 #define obstack_chunk_free free
146 /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
147 the stack pointer does not matter. The value is tested only in
148 functions that have frame pointers.
149 No definition is equivalent to always zero. */
150 #ifndef EXIT_IGNORE_STACK
151 #define EXIT_IGNORE_STACK 0
154 #ifndef HAVE_epilogue
155 #define HAVE_epilogue 0
157 #ifndef HAVE_prologue
158 #define HAVE_prologue 0
160 #ifndef HAVE_sibcall_epilogue
161 #define HAVE_sibcall_epilogue 0
165 #define LOCAL_REGNO(REGNO) 0
167 #ifndef EPILOGUE_USES
168 #define EPILOGUE_USES(REGNO) 0
171 /* The contents of the current function definition are allocated
172 in this obstack, and all are freed at the end of the function.
173 For top-level functions, this is temporary_obstack.
174 Separate obstacks are made for nested functions. */
176 extern struct obstack *function_obstack;
178 /* Number of basic blocks in the current function. */
182 /* Number of edges in the current function. */
186 /* The basic block array. */
188 varray_type basic_block_info;
190 /* The special entry and exit blocks. */
192 struct basic_block_def entry_exit_blocks[2]
197 NULL, /* local_set */
198 NULL, /* global_live_at_start */
199 NULL, /* global_live_at_end */
201 ENTRY_BLOCK, /* index */
203 -1, -1, /* eh_beg, eh_end */
211 NULL, /* local_set */
212 NULL, /* global_live_at_start */
213 NULL, /* global_live_at_end */
215 EXIT_BLOCK, /* index */
217 -1, -1, /* eh_beg, eh_end */
222 /* Nonzero if the second flow pass has completed. */
225 /* Maximum register number used in this function, plus one. */
229 /* Indexed by n, giving various register information */
231 varray_type reg_n_info;
233 /* Size of a regset for the current function,
234 in (1) bytes and (2) elements. */
239 /* Regset of regs live when calls to `setjmp'-like functions happen. */
240 /* ??? Does this exist only for the setjmp-clobbered warning message? */
242 regset regs_live_at_setjmp;
244 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
245 that have to go in the same hard reg.
246 The first two regs in the list are a pair, and the next two
247 are another pair, etc. */
250 /* Set of registers that may be eliminable. These are handled specially
251 in updating regs_ever_live. */
253 static HARD_REG_SET elim_reg_set;
255 /* The basic block structure for every insn, indexed by uid. */
257 varray_type basic_block_for_insn;
259 /* The labels mentioned in non-jump rtl. Valid during find_basic_blocks. */
260 /* ??? Should probably be using LABEL_NUSES instead. It would take a
261 bit of surgery to be able to use or co-opt the routines in jump. */
263 static rtx label_value_list;
264 static rtx tail_recursion_label_list;
266 /* Holds information for tracking conditional register life information. */
267 struct reg_cond_life_info
269 /* An EXPR_LIST of conditions under which a register is dead. */
272 /* ??? Could store mask of bytes that are dead, so that we could finally
273 track lifetimes of multi-word registers accessed via subregs. */
276 /* For use in communicating between propagate_block and its subroutines.
277 Holds all information needed to compute life and def-use information. */
279 struct propagate_block_info
281 /* The basic block we're considering. */
284 /* Bit N is set if register N is conditionally or unconditionally live. */
287 /* Bit N is set if register N is set this insn. */
290 /* Element N is the next insn that uses (hard or pseudo) register N
291 within the current basic block; or zero, if there is no such insn. */
294 /* Contains a list of all the MEMs we are tracking for dead store
298 /* If non-null, record the set of registers set in the basic block. */
301 #ifdef HAVE_conditional_execution
302 /* Indexed by register number, holds a reg_cond_life_info for each
303 register that is not unconditionally live or dead. */
304 splay_tree reg_cond_dead;
306 /* Bit N is set if register N is in an expression in reg_cond_dead. */
310 /* Non-zero if the value of CC0 is live. */
313 /* Flags controling the set of information propagate_block collects. */
317 /* Store the data structures necessary for depth-first search. */
318 struct depth_first_search_dsS {
319 /* stack for backtracking during the algorithm */
322 /* number of edges in the stack. That is, positions 0, ..., sp-1
326 /* record of basic blocks already seen by depth-first search */
327 sbitmap visited_blocks;
329 typedef struct depth_first_search_dsS *depth_first_search_ds;
331 /* Forward declarations */
332 static int count_basic_blocks PARAMS ((rtx));
333 static void find_basic_blocks_1 PARAMS ((rtx));
334 static rtx find_label_refs PARAMS ((rtx, rtx));
335 static void clear_edges PARAMS ((void));
336 static void make_edges PARAMS ((rtx));
337 static void make_label_edge PARAMS ((sbitmap *, basic_block,
339 static void make_eh_edge PARAMS ((sbitmap *, eh_nesting_info *,
340 basic_block, rtx, int));
341 static void mark_critical_edges PARAMS ((void));
342 static void move_stray_eh_region_notes PARAMS ((void));
343 static void record_active_eh_regions PARAMS ((rtx));
345 static void commit_one_edge_insertion PARAMS ((edge));
347 static void delete_unreachable_blocks PARAMS ((void));
348 static void delete_eh_regions PARAMS ((void));
349 static int can_delete_note_p PARAMS ((rtx));
350 static void expunge_block PARAMS ((basic_block));
351 static int can_delete_label_p PARAMS ((rtx));
352 static int tail_recursion_label_p PARAMS ((rtx));
353 static int merge_blocks_move_predecessor_nojumps PARAMS ((basic_block,
355 static int merge_blocks_move_successor_nojumps PARAMS ((basic_block,
357 static int merge_blocks PARAMS ((edge,basic_block,basic_block));
358 static void try_merge_blocks PARAMS ((void));
359 static void tidy_fallthru_edges PARAMS ((void));
360 static int verify_wide_reg_1 PARAMS ((rtx *, void *));
361 static void verify_wide_reg PARAMS ((int, rtx, rtx));
362 static void verify_local_live_at_start PARAMS ((regset, basic_block));
363 static int set_noop_p PARAMS ((rtx));
364 static int noop_move_p PARAMS ((rtx));
365 static void delete_noop_moves PARAMS ((rtx));
366 static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
367 static void notice_stack_pointer_modification PARAMS ((rtx));
368 static void mark_reg PARAMS ((rtx, void *));
369 static void mark_regs_live_at_end PARAMS ((regset));
370 static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
371 static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
372 static void propagate_block_delete_insn PARAMS ((basic_block, rtx));
373 static rtx propagate_block_delete_libcall PARAMS ((basic_block, rtx, rtx));
374 static int insn_dead_p PARAMS ((struct propagate_block_info *,
376 static int libcall_dead_p PARAMS ((struct propagate_block_info *,
378 static void mark_set_regs PARAMS ((struct propagate_block_info *,
380 static void mark_set_1 PARAMS ((struct propagate_block_info *,
381 enum rtx_code, rtx, rtx,
383 #ifdef HAVE_conditional_execution
384 static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
386 static void free_reg_cond_life_info PARAMS ((splay_tree_value));
387 static int flush_reg_cond_reg_1 PARAMS ((splay_tree_node, void *));
388 static void flush_reg_cond_reg PARAMS ((struct propagate_block_info *,
390 static rtx ior_reg_cond PARAMS ((rtx, rtx));
391 static rtx not_reg_cond PARAMS ((rtx));
392 static rtx nand_reg_cond PARAMS ((rtx, rtx));
395 static void attempt_auto_inc PARAMS ((struct propagate_block_info *,
396 rtx, rtx, rtx, rtx, rtx));
397 static void find_auto_inc PARAMS ((struct propagate_block_info *,
399 static int try_pre_increment_1 PARAMS ((struct propagate_block_info *,
401 static int try_pre_increment PARAMS ((rtx, rtx, HOST_WIDE_INT));
403 static void mark_used_reg PARAMS ((struct propagate_block_info *,
405 static void mark_used_regs PARAMS ((struct propagate_block_info *,
407 void dump_flow_info PARAMS ((FILE *));
408 void debug_flow_info PARAMS ((void));
409 static void dump_edge_info PARAMS ((FILE *, edge, int));
411 static void invalidate_mems_from_autoinc PARAMS ((struct propagate_block_info *,
413 static void remove_fake_successors PARAMS ((basic_block));
414 static void flow_nodes_print PARAMS ((const char *, const sbitmap, FILE *));
415 static void flow_exits_print PARAMS ((const char *, const edge *, int, FILE *));
416 static void flow_loops_cfg_dump PARAMS ((const struct loops *, FILE *));
417 static int flow_loop_nested_p PARAMS ((struct loop *, struct loop *));
418 static int flow_loop_exits_find PARAMS ((const sbitmap, edge **));
419 static int flow_loop_nodes_find PARAMS ((basic_block, basic_block, sbitmap));
420 static int flow_depth_first_order_compute PARAMS ((int *, int *));
421 static void flow_dfs_compute_reverse_init
422 PARAMS ((depth_first_search_ds));
423 static void flow_dfs_compute_reverse_add_bb
424 PARAMS ((depth_first_search_ds, basic_block));
425 static basic_block flow_dfs_compute_reverse_execute
426 PARAMS ((depth_first_search_ds));
427 static void flow_dfs_compute_reverse_finish
428 PARAMS ((depth_first_search_ds));
429 static basic_block flow_loop_pre_header_find PARAMS ((basic_block, const sbitmap *));
430 static void flow_loop_tree_node_add PARAMS ((struct loop *, struct loop *));
431 static void flow_loops_tree_build PARAMS ((struct loops *));
432 static int flow_loop_level_compute PARAMS ((struct loop *, int));
433 static int flow_loops_level_compute PARAMS ((struct loops *));
435 /* Find basic blocks of the current function.
436 F is the first insn of the function and NREGS the number of register
440 find_basic_blocks (f, nregs, file)
442 int nregs ATTRIBUTE_UNUSED;
443 FILE *file ATTRIBUTE_UNUSED;
447 /* Flush out existing data. */
448 if (basic_block_info != NULL)
454 /* Clear bb->aux on all extant basic blocks. We'll use this as a
455 tag for reuse during create_basic_block, just in case some pass
456 copies around basic block notes improperly. */
457 for (i = 0; i < n_basic_blocks; ++i)
458 BASIC_BLOCK (i)->aux = NULL;
460 VARRAY_FREE (basic_block_info);
463 n_basic_blocks = count_basic_blocks (f);
465 /* Size the basic block table. The actual structures will be allocated
466 by find_basic_blocks_1, since we want to keep the structure pointers
467 stable across calls to find_basic_blocks. */
468 /* ??? This whole issue would be much simpler if we called find_basic_blocks
469 exactly once, and thereafter we don't have a single long chain of
470 instructions at all until close to the end of compilation when we
471 actually lay them out. */
473 VARRAY_BB_INIT (basic_block_info, n_basic_blocks, "basic_block_info");
475 find_basic_blocks_1 (f);
477 /* Record the block to which an insn belongs. */
478 /* ??? This should be done another way, by which (perhaps) a label is
479 tagged directly with the basic block that it starts. It is used for
480 more than that currently, but IMO that is the only valid use. */
482 max_uid = get_max_uid ();
484 /* Leave space for insns life_analysis makes in some cases for auto-inc.
485 These cases are rare, so we don't need too much space. */
486 max_uid += max_uid / 10;
489 compute_bb_for_insn (max_uid);
491 /* Discover the edges of our cfg. */
492 record_active_eh_regions (f);
493 make_edges (label_value_list);
495 /* Do very simple cleanup now, for the benefit of code that runs between
496 here and cleanup_cfg, e.g. thread_prologue_and_epilogue_insns. */
497 tidy_fallthru_edges ();
499 mark_critical_edges ();
501 #ifdef ENABLE_CHECKING
506 /* Count the basic blocks of the function. */
509 count_basic_blocks (f)
513 register RTX_CODE prev_code;
514 register int count = 0;
516 int call_had_abnormal_edge = 0;
518 prev_code = JUMP_INSN;
519 for (insn = f; insn; insn = NEXT_INSN (insn))
521 register RTX_CODE code = GET_CODE (insn);
523 if (code == CODE_LABEL
524 || (GET_RTX_CLASS (code) == 'i'
525 && (prev_code == JUMP_INSN
526 || prev_code == BARRIER
527 || (prev_code == CALL_INSN && call_had_abnormal_edge))))
530 /* Record whether this call created an edge. */
531 if (code == CALL_INSN)
533 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
534 int region = (note ? INTVAL (XEXP (note, 0)) : 1);
536 call_had_abnormal_edge = 0;
538 /* If there is an EH region or rethrow, we have an edge. */
539 if ((eh_region && region > 0)
540 || find_reg_note (insn, REG_EH_RETHROW, NULL_RTX))
541 call_had_abnormal_edge = 1;
542 else if (nonlocal_goto_handler_labels && region >= 0)
543 /* If there is a nonlocal goto label and the specified
544 region number isn't -1, we have an edge. (0 means
545 no throw, but might have a nonlocal goto). */
546 call_had_abnormal_edge = 1;
551 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
553 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
557 /* The rest of the compiler works a bit smoother when we don't have to
558 check for the edge case of do-nothing functions with no basic blocks. */
561 emit_insn (gen_rtx_USE (VOIDmode, const0_rtx));
568 /* Scan a list of insns for labels referred to other than by jumps.
569 This is used to scan the alternatives of a call placeholder. */
571 find_label_refs (f, lvl)
577 for (insn = f; insn; insn = NEXT_INSN (insn))
582 /* Make a list of all labels referred to other than by jumps
583 (which just don't have the REG_LABEL notes).
585 Make a special exception for labels followed by an ADDR*VEC,
586 as this would be a part of the tablejump setup code.
588 Make a special exception for the eh_return_stub_label, which
589 we know isn't part of any otherwise visible control flow. */
591 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
592 if (REG_NOTE_KIND (note) == REG_LABEL)
594 rtx lab = XEXP (note, 0), next;
596 if (lab == eh_return_stub_label)
598 else if ((next = next_nonnote_insn (lab)) != NULL
599 && GET_CODE (next) == JUMP_INSN
600 && (GET_CODE (PATTERN (next)) == ADDR_VEC
601 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
603 else if (GET_CODE (lab) == NOTE)
606 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
613 /* Find all basic blocks of the function whose first insn is F.
615 Collect and return a list of labels whose addresses are taken. This
616 will be used in make_edges for use with computed gotos. */
619 find_basic_blocks_1 (f)
622 register rtx insn, next;
624 rtx bb_note = NULL_RTX;
625 rtx eh_list = NULL_RTX;
631 /* We process the instructions in a slightly different way than we did
632 previously. This is so that we see a NOTE_BASIC_BLOCK after we have
633 closed out the previous block, so that it gets attached at the proper
634 place. Since this form should be equivalent to the previous,
635 count_basic_blocks continues to use the old form as a check. */
637 for (insn = f; insn; insn = next)
639 enum rtx_code code = GET_CODE (insn);
641 next = NEXT_INSN (insn);
647 int kind = NOTE_LINE_NUMBER (insn);
649 /* Keep a LIFO list of the currently active exception notes. */
650 if (kind == NOTE_INSN_EH_REGION_BEG)
651 eh_list = alloc_INSN_LIST (insn, eh_list);
652 else if (kind == NOTE_INSN_EH_REGION_END)
656 eh_list = XEXP (eh_list, 1);
657 free_INSN_LIST_node (t);
660 /* Look for basic block notes with which to keep the
661 basic_block_info pointers stable. Unthread the note now;
662 we'll put it back at the right place in create_basic_block.
663 Or not at all if we've already found a note in this block. */
664 else if (kind == NOTE_INSN_BASIC_BLOCK)
666 if (bb_note == NULL_RTX)
669 next = flow_delete_insn (insn);
675 /* A basic block starts at a label. If we've closed one off due
676 to a barrier or some such, no need to do it again. */
677 if (head != NULL_RTX)
679 /* While we now have edge lists with which other portions of
680 the compiler might determine a call ending a basic block
681 does not imply an abnormal edge, it will be a bit before
682 everything can be updated. So continue to emit a noop at
683 the end of such a block. */
684 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
686 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
687 end = emit_insn_after (nop, end);
690 create_basic_block (i++, head, end, bb_note);
698 /* A basic block ends at a jump. */
699 if (head == NULL_RTX)
703 /* ??? Make a special check for table jumps. The way this
704 happens is truly and amazingly gross. We are about to
705 create a basic block that contains just a code label and
706 an addr*vec jump insn. Worse, an addr_diff_vec creates
707 its own natural loop.
709 Prevent this bit of brain damage, pasting things together
710 correctly in make_edges.
712 The correct solution involves emitting the table directly
713 on the tablejump instruction as a note, or JUMP_LABEL. */
715 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
716 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
724 goto new_bb_inclusive;
727 /* A basic block ends at a barrier. It may be that an unconditional
728 jump already closed the basic block -- no need to do it again. */
729 if (head == NULL_RTX)
732 /* While we now have edge lists with which other portions of the
733 compiler might determine a call ending a basic block does not
734 imply an abnormal edge, it will be a bit before everything can
735 be updated. So continue to emit a noop at the end of such a
737 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
739 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
740 end = emit_insn_after (nop, end);
742 goto new_bb_exclusive;
746 /* Record whether this call created an edge. */
747 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
748 int region = (note ? INTVAL (XEXP (note, 0)) : 1);
749 int call_has_abnormal_edge = 0;
751 if (GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
753 /* Scan each of the alternatives for label refs. */
754 lvl = find_label_refs (XEXP (PATTERN (insn), 0), lvl);
755 lvl = find_label_refs (XEXP (PATTERN (insn), 1), lvl);
756 lvl = find_label_refs (XEXP (PATTERN (insn), 2), lvl);
757 /* Record its tail recursion label, if any. */
758 if (XEXP (PATTERN (insn), 3) != NULL_RTX)
759 trll = alloc_EXPR_LIST (0, XEXP (PATTERN (insn), 3), trll);
762 /* If there is an EH region or rethrow, we have an edge. */
763 if ((eh_list && region > 0)
764 || find_reg_note (insn, REG_EH_RETHROW, NULL_RTX))
765 call_has_abnormal_edge = 1;
766 else if (nonlocal_goto_handler_labels && region >= 0)
767 /* If there is a nonlocal goto label and the specified
768 region number isn't -1, we have an edge. (0 means
769 no throw, but might have a nonlocal goto). */
770 call_has_abnormal_edge = 1;
772 /* A basic block ends at a call that can either throw or
773 do a non-local goto. */
774 if (call_has_abnormal_edge)
777 if (head == NULL_RTX)
782 create_basic_block (i++, head, end, bb_note);
783 head = end = NULL_RTX;
791 if (GET_RTX_CLASS (code) == 'i')
793 if (head == NULL_RTX)
800 if (GET_RTX_CLASS (code) == 'i')
804 /* Make a list of all labels referred to other than by jumps
805 (which just don't have the REG_LABEL notes).
807 Make a special exception for labels followed by an ADDR*VEC,
808 as this would be a part of the tablejump setup code.
810 Make a special exception for the eh_return_stub_label, which
811 we know isn't part of any otherwise visible control flow. */
813 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
814 if (REG_NOTE_KIND (note) == REG_LABEL)
816 rtx lab = XEXP (note, 0), next;
818 if (lab == eh_return_stub_label)
820 else if ((next = next_nonnote_insn (lab)) != NULL
821 && GET_CODE (next) == JUMP_INSN
822 && (GET_CODE (PATTERN (next)) == ADDR_VEC
823 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
825 else if (GET_CODE (lab) == NOTE)
828 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
833 if (head != NULL_RTX)
834 create_basic_block (i++, head, end, bb_note);
836 flow_delete_insn (bb_note);
838 if (i != n_basic_blocks)
841 label_value_list = lvl;
842 tail_recursion_label_list = trll;
845 /* Tidy the CFG by deleting unreachable code and whatnot. */
851 delete_unreachable_blocks ();
852 move_stray_eh_region_notes ();
853 record_active_eh_regions (f);
855 mark_critical_edges ();
857 /* Kill the data we won't maintain. */
858 free_EXPR_LIST_list (&label_value_list);
859 free_EXPR_LIST_list (&tail_recursion_label_list);
862 /* Create a new basic block consisting of the instructions between
863 HEAD and END inclusive. Reuses the note and basic block struct
864 in BB_NOTE, if any. */
867 create_basic_block (index, head, end, bb_note)
869 rtx head, end, bb_note;
874 && ! RTX_INTEGRATED_P (bb_note)
875 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
878 /* If we found an existing note, thread it back onto the chain. */
882 if (GET_CODE (head) == CODE_LABEL)
886 after = PREV_INSN (head);
890 if (after != bb_note && NEXT_INSN (after) != bb_note)
891 reorder_insns (bb_note, bb_note, after);
895 /* Otherwise we must create a note and a basic block structure.
896 Since we allow basic block structs in rtl, give the struct
897 the same lifetime by allocating it off the function obstack
898 rather than using malloc. */
900 bb = (basic_block) obstack_alloc (function_obstack, sizeof (*bb));
901 memset (bb, 0, sizeof (*bb));
903 if (GET_CODE (head) == CODE_LABEL)
904 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
907 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
910 NOTE_BASIC_BLOCK (bb_note) = bb;
913 /* Always include the bb note in the block. */
914 if (NEXT_INSN (end) == bb_note)
920 BASIC_BLOCK (index) = bb;
922 /* Tag the block so that we know it has been used when considering
923 other basic block notes. */
927 /* Records the basic block struct in BB_FOR_INSN, for every instruction
928 indexed by INSN_UID. MAX is the size of the array. */
931 compute_bb_for_insn (max)
936 if (basic_block_for_insn)
937 VARRAY_FREE (basic_block_for_insn);
938 VARRAY_BB_INIT (basic_block_for_insn, max, "basic_block_for_insn");
940 for (i = 0; i < n_basic_blocks; ++i)
942 basic_block bb = BASIC_BLOCK (i);
949 int uid = INSN_UID (insn);
951 VARRAY_BB (basic_block_for_insn, uid) = bb;
954 insn = NEXT_INSN (insn);
959 /* Free the memory associated with the edge structures. */
967 for (i = 0; i < n_basic_blocks; ++i)
969 basic_block bb = BASIC_BLOCK (i);
971 for (e = bb->succ; e; e = n)
981 for (e = ENTRY_BLOCK_PTR->succ; e; e = n)
987 ENTRY_BLOCK_PTR->succ = 0;
988 EXIT_BLOCK_PTR->pred = 0;
993 /* Identify the edges between basic blocks.
995 NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks
996 that are otherwise unreachable may be reachable with a non-local goto.
998 BB_EH_END is an array indexed by basic block number in which we record
999 the list of exception regions active at the end of the basic block. */
1002 make_edges (label_value_list)
1003 rtx label_value_list;
1006 eh_nesting_info *eh_nest_info = init_eh_nesting_info ();
1007 sbitmap *edge_cache = NULL;
1009 /* Assume no computed jump; revise as we create edges. */
1010 current_function_has_computed_jump = 0;
1012 /* Heavy use of computed goto in machine-generated code can lead to
1013 nearly fully-connected CFGs. In that case we spend a significant
1014 amount of time searching the edge lists for duplicates. */
1015 if (forced_labels || label_value_list)
1017 edge_cache = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
1018 sbitmap_vector_zero (edge_cache, n_basic_blocks);
1021 /* By nature of the way these get numbered, block 0 is always the entry. */
1022 make_edge (edge_cache, ENTRY_BLOCK_PTR, BASIC_BLOCK (0), EDGE_FALLTHRU);
1024 for (i = 0; i < n_basic_blocks; ++i)
1026 basic_block bb = BASIC_BLOCK (i);
1029 int force_fallthru = 0;
1031 /* Examine the last instruction of the block, and discover the
1032 ways we can leave the block. */
1035 code = GET_CODE (insn);
1038 if (code == JUMP_INSN)
1042 /* ??? Recognize a tablejump and do the right thing. */
1043 if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1044 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1045 && GET_CODE (tmp) == JUMP_INSN
1046 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1047 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1052 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1053 vec = XVEC (PATTERN (tmp), 0);
1055 vec = XVEC (PATTERN (tmp), 1);
1057 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1058 make_label_edge (edge_cache, bb,
1059 XEXP (RTVEC_ELT (vec, j), 0), 0);
1061 /* Some targets (eg, ARM) emit a conditional jump that also
1062 contains the out-of-range target. Scan for these and
1063 add an edge if necessary. */
1064 if ((tmp = single_set (insn)) != NULL
1065 && SET_DEST (tmp) == pc_rtx
1066 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1067 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF)
1068 make_label_edge (edge_cache, bb,
1069 XEXP (XEXP (SET_SRC (tmp), 2), 0), 0);
1071 #ifdef CASE_DROPS_THROUGH
1072 /* Silly VAXen. The ADDR_VEC is going to be in the way of
1073 us naturally detecting fallthru into the next block. */
1078 /* If this is a computed jump, then mark it as reaching
1079 everything on the label_value_list and forced_labels list. */
1080 else if (computed_jump_p (insn))
1082 current_function_has_computed_jump = 1;
1084 for (x = label_value_list; x; x = XEXP (x, 1))
1085 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1087 for (x = forced_labels; x; x = XEXP (x, 1))
1088 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1091 /* Returns create an exit out. */
1092 else if (returnjump_p (insn))
1093 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, 0);
1095 /* Otherwise, we have a plain conditional or unconditional jump. */
1098 if (! JUMP_LABEL (insn))
1100 make_label_edge (edge_cache, bb, JUMP_LABEL (insn), 0);
1104 /* If this is a sibling call insn, then this is in effect a
1105 combined call and return, and so we need an edge to the
1106 exit block. No need to worry about EH edges, since we
1107 wouldn't have created the sibling call in the first place. */
1109 if (code == CALL_INSN && SIBLING_CALL_P (insn))
1110 make_edge (edge_cache, bb, EXIT_BLOCK_PTR,
1111 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1114 /* If this is a CALL_INSN, then mark it as reaching the active EH
1115 handler for this CALL_INSN. If we're handling asynchronous
1116 exceptions then any insn can reach any of the active handlers.
1118 Also mark the CALL_INSN as reaching any nonlocal goto handler. */
1120 if (code == CALL_INSN || asynchronous_exceptions)
1122 /* Add any appropriate EH edges. We do this unconditionally
1123 since there may be a REG_EH_REGION or REG_EH_RETHROW note
1124 on the call, and this needn't be within an EH region. */
1125 make_eh_edge (edge_cache, eh_nest_info, bb, insn, bb->eh_end);
1127 /* If we have asynchronous exceptions, do the same for *all*
1128 exception regions active in the block. */
1129 if (asynchronous_exceptions
1130 && bb->eh_beg != bb->eh_end)
1132 if (bb->eh_beg >= 0)
1133 make_eh_edge (edge_cache, eh_nest_info, bb,
1134 NULL_RTX, bb->eh_beg);
1136 for (x = bb->head; x != bb->end; x = NEXT_INSN (x))
1137 if (GET_CODE (x) == NOTE
1138 && (NOTE_LINE_NUMBER (x) == NOTE_INSN_EH_REGION_BEG
1139 || NOTE_LINE_NUMBER (x) == NOTE_INSN_EH_REGION_END))
1141 int region = NOTE_EH_HANDLER (x);
1142 make_eh_edge (edge_cache, eh_nest_info, bb,
1147 if (code == CALL_INSN && nonlocal_goto_handler_labels)
1149 /* ??? This could be made smarter: in some cases it's possible
1150 to tell that certain calls will not do a nonlocal goto.
1152 For example, if the nested functions that do the nonlocal
1153 gotos do not have their addresses taken, then only calls to
1154 those functions or to other nested functions that use them
1155 could possibly do nonlocal gotos. */
1156 /* We do know that a REG_EH_REGION note with a value less
1157 than 0 is guaranteed not to perform a non-local goto. */
1158 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
1159 if (!note || INTVAL (XEXP (note, 0)) >= 0)
1160 for (x = nonlocal_goto_handler_labels; x; x = XEXP (x, 1))
1161 make_label_edge (edge_cache, bb, XEXP (x, 0),
1162 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1166 /* We know something about the structure of the function __throw in
1167 libgcc2.c. It is the only function that ever contains eh_stub
1168 labels. It modifies its return address so that the last block
1169 returns to one of the eh_stub labels within it. So we have to
1170 make additional edges in the flow graph. */
1171 if (i + 1 == n_basic_blocks && eh_return_stub_label != 0)
1172 make_label_edge (edge_cache, bb, eh_return_stub_label, EDGE_EH);
1174 /* Find out if we can drop through to the next block. */
1175 insn = next_nonnote_insn (insn);
1176 if (!insn || (i + 1 == n_basic_blocks && force_fallthru))
1177 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU);
1178 else if (i + 1 < n_basic_blocks)
1180 rtx tmp = BLOCK_HEAD (i + 1);
1181 if (GET_CODE (tmp) == NOTE)
1182 tmp = next_nonnote_insn (tmp);
1183 if (force_fallthru || insn == tmp)
1184 make_edge (edge_cache, bb, BASIC_BLOCK (i + 1), EDGE_FALLTHRU);
1188 free_eh_nesting_info (eh_nest_info);
1190 sbitmap_vector_free (edge_cache);
1193 /* Create an edge between two basic blocks. FLAGS are auxiliary information
1194 about the edge that is accumulated between calls. */
1197 make_edge (edge_cache, src, dst, flags)
1198 sbitmap *edge_cache;
1199 basic_block src, dst;
1205 /* Don't bother with edge cache for ENTRY or EXIT; there aren't that
1206 many edges to them, and we didn't allocate memory for it. */
1207 use_edge_cache = (edge_cache
1208 && src != ENTRY_BLOCK_PTR
1209 && dst != EXIT_BLOCK_PTR);
1211 /* Make sure we don't add duplicate edges. */
1212 if (! use_edge_cache || TEST_BIT (edge_cache[src->index], dst->index))
1213 for (e = src->succ; e; e = e->succ_next)
1220 e = (edge) xcalloc (1, sizeof (*e));
1223 e->succ_next = src->succ;
1224 e->pred_next = dst->pred;
1233 SET_BIT (edge_cache[src->index], dst->index);
1236 /* Create an edge from a basic block to a label. */
1239 make_label_edge (edge_cache, src, label, flags)
1240 sbitmap *edge_cache;
1245 if (GET_CODE (label) != CODE_LABEL)
1248 /* If the label was never emitted, this insn is junk, but avoid a
1249 crash trying to refer to BLOCK_FOR_INSN (label). This can happen
1250 as a result of a syntax error and a diagnostic has already been
1253 if (INSN_UID (label) == 0)
1256 make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags);
1259 /* Create the edges generated by INSN in REGION. */
1262 make_eh_edge (edge_cache, eh_nest_info, src, insn, region)
1263 sbitmap *edge_cache;
1264 eh_nesting_info *eh_nest_info;
1269 handler_info **handler_list;
1272 is_call = (insn && GET_CODE (insn) == CALL_INSN ? EDGE_ABNORMAL_CALL : 0);
1273 num = reachable_handlers (region, eh_nest_info, insn, &handler_list);
1276 make_label_edge (edge_cache, src, handler_list[num]->handler_label,
1277 EDGE_ABNORMAL | EDGE_EH | is_call);
1281 /* EH_REGION notes appearing between basic blocks is ambiguous, and even
1282 dangerous if we intend to move basic blocks around. Move such notes
1283 into the following block. */
1286 move_stray_eh_region_notes ()
1291 if (n_basic_blocks < 2)
1294 b2 = BASIC_BLOCK (n_basic_blocks - 1);
1295 for (i = n_basic_blocks - 2; i >= 0; --i, b2 = b1)
1297 rtx insn, next, list = NULL_RTX;
1299 b1 = BASIC_BLOCK (i);
1300 for (insn = NEXT_INSN (b1->end); insn != b2->head; insn = next)
1302 next = NEXT_INSN (insn);
1303 if (GET_CODE (insn) == NOTE
1304 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG
1305 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
1307 /* Unlink from the insn chain. */
1308 NEXT_INSN (PREV_INSN (insn)) = next;
1309 PREV_INSN (next) = PREV_INSN (insn);
1312 NEXT_INSN (insn) = list;
1317 if (list == NULL_RTX)
1320 /* Find where to insert these things. */
1322 if (GET_CODE (insn) == CODE_LABEL)
1323 insn = NEXT_INSN (insn);
1327 next = NEXT_INSN (list);
1328 add_insn_after (list, insn);
1334 /* Recompute eh_beg/eh_end for each basic block. */
1337 record_active_eh_regions (f)
1340 rtx insn, eh_list = NULL_RTX;
1342 basic_block bb = BASIC_BLOCK (0);
1344 for (insn = f; insn; insn = NEXT_INSN (insn))
1346 if (bb->head == insn)
1347 bb->eh_beg = (eh_list ? NOTE_EH_HANDLER (XEXP (eh_list, 0)) : -1);
1349 if (GET_CODE (insn) == NOTE)
1351 int kind = NOTE_LINE_NUMBER (insn);
1352 if (kind == NOTE_INSN_EH_REGION_BEG)
1353 eh_list = alloc_INSN_LIST (insn, eh_list);
1354 else if (kind == NOTE_INSN_EH_REGION_END)
1356 rtx t = XEXP (eh_list, 1);
1357 free_INSN_LIST_node (eh_list);
1362 if (bb->end == insn)
1364 bb->eh_end = (eh_list ? NOTE_EH_HANDLER (XEXP (eh_list, 0)) : -1);
1366 if (i == n_basic_blocks)
1368 bb = BASIC_BLOCK (i);
1373 /* Identify critical edges and set the bits appropriately. */
1376 mark_critical_edges ()
1378 int i, n = n_basic_blocks;
1381 /* We begin with the entry block. This is not terribly important now,
1382 but could be if a front end (Fortran) implemented alternate entry
1384 bb = ENTRY_BLOCK_PTR;
1391 /* (1) Critical edges must have a source with multiple successors. */
1392 if (bb->succ && bb->succ->succ_next)
1394 for (e = bb->succ; e; e = e->succ_next)
1396 /* (2) Critical edges must have a destination with multiple
1397 predecessors. Note that we know there is at least one
1398 predecessor -- the edge we followed to get here. */
1399 if (e->dest->pred->pred_next)
1400 e->flags |= EDGE_CRITICAL;
1402 e->flags &= ~EDGE_CRITICAL;
1407 for (e = bb->succ; e; e = e->succ_next)
1408 e->flags &= ~EDGE_CRITICAL;
1413 bb = BASIC_BLOCK (i);
1417 /* Split a (typically critical) edge. Return the new block.
1418 Abort on abnormal edges.
1420 ??? The code generally expects to be called on critical edges.
1421 The case of a block ending in an unconditional jump to a
1422 block with multiple predecessors is not handled optimally. */
1425 split_edge (edge_in)
1428 basic_block old_pred, bb, old_succ;
1433 /* Abnormal edges cannot be split. */
1434 if ((edge_in->flags & EDGE_ABNORMAL) != 0)
1437 old_pred = edge_in->src;
1438 old_succ = edge_in->dest;
1440 /* Remove the existing edge from the destination's pred list. */
1443 for (pp = &old_succ->pred; *pp != edge_in; pp = &(*pp)->pred_next)
1445 *pp = edge_in->pred_next;
1446 edge_in->pred_next = NULL;
1449 /* Create the new structures. */
1450 bb = (basic_block) obstack_alloc (function_obstack, sizeof (*bb));
1451 edge_out = (edge) xcalloc (1, sizeof (*edge_out));
1454 memset (bb, 0, sizeof (*bb));
1456 /* ??? This info is likely going to be out of date very soon. */
1457 if (old_succ->global_live_at_start)
1459 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (function_obstack);
1460 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (function_obstack);
1461 COPY_REG_SET (bb->global_live_at_start, old_succ->global_live_at_start);
1462 COPY_REG_SET (bb->global_live_at_end, old_succ->global_live_at_start);
1467 bb->succ = edge_out;
1468 bb->count = edge_in->count;
1471 edge_in->flags &= ~EDGE_CRITICAL;
1473 edge_out->pred_next = old_succ->pred;
1474 edge_out->succ_next = NULL;
1476 edge_out->dest = old_succ;
1477 edge_out->flags = EDGE_FALLTHRU;
1478 edge_out->probability = REG_BR_PROB_BASE;
1479 edge_out->count = edge_in->count;
1481 old_succ->pred = edge_out;
1483 /* Tricky case -- if there existed a fallthru into the successor
1484 (and we're not it) we must add a new unconditional jump around
1485 the new block we're actually interested in.
1487 Further, if that edge is critical, this means a second new basic
1488 block must be created to hold it. In order to simplify correct
1489 insn placement, do this before we touch the existing basic block
1490 ordering for the block we were really wanting. */
1491 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1494 for (e = edge_out->pred_next; e; e = e->pred_next)
1495 if (e->flags & EDGE_FALLTHRU)
1500 basic_block jump_block;
1503 if ((e->flags & EDGE_CRITICAL) == 0
1504 && e->src != ENTRY_BLOCK_PTR)
1506 /* Non critical -- we can simply add a jump to the end
1507 of the existing predecessor. */
1508 jump_block = e->src;
1512 /* We need a new block to hold the jump. The simplest
1513 way to do the bulk of the work here is to recursively
1515 jump_block = split_edge (e);
1516 e = jump_block->succ;
1519 /* Now add the jump insn ... */
1520 pos = emit_jump_insn_after (gen_jump (old_succ->head),
1522 jump_block->end = pos;
1523 if (basic_block_for_insn)
1524 set_block_for_insn (pos, jump_block);
1525 emit_barrier_after (pos);
1527 /* ... let jump know that label is in use, ... */
1528 JUMP_LABEL (pos) = old_succ->head;
1529 ++LABEL_NUSES (old_succ->head);
1531 /* ... and clear fallthru on the outgoing edge. */
1532 e->flags &= ~EDGE_FALLTHRU;
1534 /* Continue splitting the interesting edge. */
1538 /* Place the new block just in front of the successor. */
1539 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
1540 if (old_succ == EXIT_BLOCK_PTR)
1541 j = n_basic_blocks - 1;
1543 j = old_succ->index;
1544 for (i = n_basic_blocks - 1; i > j; --i)
1546 basic_block tmp = BASIC_BLOCK (i - 1);
1547 BASIC_BLOCK (i) = tmp;
1550 BASIC_BLOCK (i) = bb;
1553 /* Create the basic block note.
1555 Where we place the note can have a noticable impact on the generated
1556 code. Consider this cfg:
1566 If we need to insert an insn on the edge from block 0 to block 1,
1567 we want to ensure the instructions we insert are outside of any
1568 loop notes that physically sit between block 0 and block 1. Otherwise
1569 we confuse the loop optimizer into thinking the loop is a phony. */
1570 if (old_succ != EXIT_BLOCK_PTR
1571 && PREV_INSN (old_succ->head)
1572 && GET_CODE (PREV_INSN (old_succ->head)) == NOTE
1573 && NOTE_LINE_NUMBER (PREV_INSN (old_succ->head)) == NOTE_INSN_LOOP_BEG)
1574 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
1575 PREV_INSN (old_succ->head));
1576 else if (old_succ != EXIT_BLOCK_PTR)
1577 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, old_succ->head);
1579 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
1580 NOTE_BASIC_BLOCK (bb_note) = bb;
1581 bb->head = bb->end = bb_note;
1583 /* Not quite simple -- for non-fallthru edges, we must adjust the
1584 predecessor's jump instruction to target our new block. */
1585 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1587 rtx tmp, insn = old_pred->end;
1588 rtx old_label = old_succ->head;
1589 rtx new_label = gen_label_rtx ();
1591 if (GET_CODE (insn) != JUMP_INSN)
1594 /* ??? Recognize a tablejump and adjust all matching cases. */
1595 if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1596 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1597 && GET_CODE (tmp) == JUMP_INSN
1598 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1599 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1604 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1605 vec = XVEC (PATTERN (tmp), 0);
1607 vec = XVEC (PATTERN (tmp), 1);
1609 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1610 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
1612 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (VOIDmode, new_label);
1613 --LABEL_NUSES (old_label);
1614 ++LABEL_NUSES (new_label);
1617 /* Handle casesi dispatch insns */
1618 if ((tmp = single_set (insn)) != NULL
1619 && SET_DEST (tmp) == pc_rtx
1620 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1621 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
1622 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
1624 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (VOIDmode,
1626 --LABEL_NUSES (old_label);
1627 ++LABEL_NUSES (new_label);
1632 /* This would have indicated an abnormal edge. */
1633 if (computed_jump_p (insn))
1636 /* A return instruction can't be redirected. */
1637 if (returnjump_p (insn))
1640 /* If the insn doesn't go where we think, we're confused. */
1641 if (JUMP_LABEL (insn) != old_label)
1644 redirect_jump (insn, new_label, 0);
1647 emit_label_before (new_label, bb_note);
1648 bb->head = new_label;
1654 /* Queue instructions for insertion on an edge between two basic blocks.
1655 The new instructions and basic blocks (if any) will not appear in the
1656 CFG until commit_edge_insertions is called. */
1659 insert_insn_on_edge (pattern, e)
1663 /* We cannot insert instructions on an abnormal critical edge.
1664 It will be easier to find the culprit if we die now. */
1665 if ((e->flags & (EDGE_ABNORMAL|EDGE_CRITICAL))
1666 == (EDGE_ABNORMAL|EDGE_CRITICAL))
1669 if (e->insns == NULL_RTX)
1672 push_to_sequence (e->insns);
1674 emit_insn (pattern);
1676 e->insns = get_insns ();
1680 /* Update the CFG for the instructions queued on edge E. */
1683 commit_one_edge_insertion (e)
1686 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
1689 /* Pull the insns off the edge now since the edge might go away. */
1691 e->insns = NULL_RTX;
1693 /* Figure out where to put these things. If the destination has
1694 one predecessor, insert there. Except for the exit block. */
1695 if (e->dest->pred->pred_next == NULL
1696 && e->dest != EXIT_BLOCK_PTR)
1700 /* Get the location correct wrt a code label, and "nice" wrt
1701 a basic block note, and before everything else. */
1703 if (GET_CODE (tmp) == CODE_LABEL)
1704 tmp = NEXT_INSN (tmp);
1705 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
1706 tmp = NEXT_INSN (tmp);
1707 if (tmp == bb->head)
1710 after = PREV_INSN (tmp);
1713 /* If the source has one successor and the edge is not abnormal,
1714 insert there. Except for the entry block. */
1715 else if ((e->flags & EDGE_ABNORMAL) == 0
1716 && e->src->succ->succ_next == NULL
1717 && e->src != ENTRY_BLOCK_PTR)
1720 /* It is possible to have a non-simple jump here. Consider a target
1721 where some forms of unconditional jumps clobber a register. This
1722 happens on the fr30 for example.
1724 We know this block has a single successor, so we can just emit
1725 the queued insns before the jump. */
1726 if (GET_CODE (bb->end) == JUMP_INSN)
1732 /* We'd better be fallthru, or we've lost track of what's what. */
1733 if ((e->flags & EDGE_FALLTHRU) == 0)
1740 /* Otherwise we must split the edge. */
1743 bb = split_edge (e);
1747 /* Now that we've found the spot, do the insertion. */
1749 /* Set the new block number for these insns, if structure is allocated. */
1750 if (basic_block_for_insn)
1753 for (i = insns; i != NULL_RTX; i = NEXT_INSN (i))
1754 set_block_for_insn (i, bb);
1759 emit_insns_before (insns, before);
1760 if (before == bb->head)
1763 last = prev_nonnote_insn (before);
1767 last = emit_insns_after (insns, after);
1768 if (after == bb->end)
1772 if (returnjump_p (last))
1774 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1775 This is not currently a problem because this only happens
1776 for the (single) epilogue, which already has a fallthru edge
1780 if (e->dest != EXIT_BLOCK_PTR
1781 || e->succ_next != NULL
1782 || (e->flags & EDGE_FALLTHRU) == 0)
1784 e->flags &= ~EDGE_FALLTHRU;
1786 emit_barrier_after (last);
1790 flow_delete_insn (before);
1792 else if (GET_CODE (last) == JUMP_INSN)
1796 /* Update the CFG for all queued instructions. */
1799 commit_edge_insertions ()
1804 #ifdef ENABLE_CHECKING
1805 verify_flow_info ();
1809 bb = ENTRY_BLOCK_PTR;
1814 for (e = bb->succ; e; e = next)
1816 next = e->succ_next;
1818 commit_one_edge_insertion (e);
1821 if (++i >= n_basic_blocks)
1823 bb = BASIC_BLOCK (i);
1827 /* Delete all unreachable basic blocks. */
1830 delete_unreachable_blocks ()
1832 basic_block *worklist, *tos;
1833 int deleted_handler;
1838 tos = worklist = (basic_block *) xmalloc (sizeof (basic_block) * n);
1840 /* Use basic_block->aux as a marker. Clear them all. */
1842 for (i = 0; i < n; ++i)
1843 BASIC_BLOCK (i)->aux = NULL;
1845 /* Add our starting points to the worklist. Almost always there will
1846 be only one. It isn't inconcievable that we might one day directly
1847 support Fortran alternate entry points. */
1849 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
1853 /* Mark the block with a handy non-null value. */
1857 /* Iterate: find everything reachable from what we've already seen. */
1859 while (tos != worklist)
1861 basic_block b = *--tos;
1863 for (e = b->succ; e; e = e->succ_next)
1871 /* Delete all unreachable basic blocks. Count down so that we don't
1872 interfere with the block renumbering that happens in flow_delete_block. */
1874 deleted_handler = 0;
1876 for (i = n - 1; i >= 0; --i)
1878 basic_block b = BASIC_BLOCK (i);
1881 /* This block was found. Tidy up the mark. */
1884 deleted_handler |= flow_delete_block (b);
1887 tidy_fallthru_edges ();
1889 /* If we deleted an exception handler, we may have EH region begin/end
1890 blocks to remove as well. */
1891 if (deleted_handler)
1892 delete_eh_regions ();
1897 /* Find EH regions for which there is no longer a handler, and delete them. */
1900 delete_eh_regions ()
1904 update_rethrow_references ();
1906 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
1907 if (GET_CODE (insn) == NOTE)
1909 if ((NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
1910 || (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
1912 int num = NOTE_EH_HANDLER (insn);
1913 /* A NULL handler indicates a region is no longer needed,
1914 as long as its rethrow label isn't used. */
1915 if (get_first_handler (num) == NULL && ! rethrow_used (num))
1917 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
1918 NOTE_SOURCE_FILE (insn) = 0;
1924 /* Return true if NOTE is not one of the ones that must be kept paired,
1925 so that we may simply delete them. */
1928 can_delete_note_p (note)
1931 return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED
1932 || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK);
1935 /* Unlink a chain of insns between START and FINISH, leaving notes
1936 that must be paired. */
1939 flow_delete_insn_chain (start, finish)
1942 /* Unchain the insns one by one. It would be quicker to delete all
1943 of these with a single unchaining, rather than one at a time, but
1944 we need to keep the NOTE's. */
1950 next = NEXT_INSN (start);
1951 if (GET_CODE (start) == NOTE && !can_delete_note_p (start))
1953 else if (GET_CODE (start) == CODE_LABEL
1954 && ! can_delete_label_p (start))
1956 const char *name = LABEL_NAME (start);
1957 PUT_CODE (start, NOTE);
1958 NOTE_LINE_NUMBER (start) = NOTE_INSN_DELETED_LABEL;
1959 NOTE_SOURCE_FILE (start) = name;
1962 next = flow_delete_insn (start);
1964 if (start == finish)
1970 /* Delete the insns in a (non-live) block. We physically delete every
1971 non-deleted-note insn, and update the flow graph appropriately.
1973 Return nonzero if we deleted an exception handler. */
1975 /* ??? Preserving all such notes strikes me as wrong. It would be nice
1976 to post-process the stream to remove empty blocks, loops, ranges, etc. */
1979 flow_delete_block (b)
1982 int deleted_handler = 0;
1985 /* If the head of this block is a CODE_LABEL, then it might be the
1986 label for an exception handler which can't be reached.
1988 We need to remove the label from the exception_handler_label list
1989 and remove the associated NOTE_INSN_EH_REGION_BEG and
1990 NOTE_INSN_EH_REGION_END notes. */
1994 never_reached_warning (insn);
1996 if (GET_CODE (insn) == CODE_LABEL)
1998 rtx x, *prev = &exception_handler_labels;
2000 for (x = exception_handler_labels; x; x = XEXP (x, 1))
2002 if (XEXP (x, 0) == insn)
2004 /* Found a match, splice this label out of the EH label list. */
2005 *prev = XEXP (x, 1);
2006 XEXP (x, 1) = NULL_RTX;
2007 XEXP (x, 0) = NULL_RTX;
2009 /* Remove the handler from all regions */
2010 remove_handler (insn);
2011 deleted_handler = 1;
2014 prev = &XEXP (x, 1);
2018 /* Include any jump table following the basic block. */
2020 if (GET_CODE (end) == JUMP_INSN
2021 && (tmp = JUMP_LABEL (end)) != NULL_RTX
2022 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
2023 && GET_CODE (tmp) == JUMP_INSN
2024 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
2025 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
2028 /* Include any barrier that may follow the basic block. */
2029 tmp = next_nonnote_insn (end);
2030 if (tmp && GET_CODE (tmp) == BARRIER)
2033 /* Selectively delete the entire chain. */
2034 flow_delete_insn_chain (insn, end);
2036 /* Remove the edges into and out of this block. Note that there may
2037 indeed be edges in, if we are removing an unreachable loop. */
2041 for (e = b->pred; e; e = next)
2043 for (q = &e->src->succ; *q != e; q = &(*q)->succ_next)
2046 next = e->pred_next;
2050 for (e = b->succ; e; e = next)
2052 for (q = &e->dest->pred; *q != e; q = &(*q)->pred_next)
2055 next = e->succ_next;
2064 /* Remove the basic block from the array, and compact behind it. */
2067 return deleted_handler;
2070 /* Remove block B from the basic block array and compact behind it. */
2076 int i, n = n_basic_blocks;
2078 for (i = b->index; i + 1 < n; ++i)
2080 basic_block x = BASIC_BLOCK (i + 1);
2081 BASIC_BLOCK (i) = x;
2085 basic_block_info->num_elements--;
2089 /* Delete INSN by patching it out. Return the next insn. */
2092 flow_delete_insn (insn)
2095 rtx prev = PREV_INSN (insn);
2096 rtx next = NEXT_INSN (insn);
2099 PREV_INSN (insn) = NULL_RTX;
2100 NEXT_INSN (insn) = NULL_RTX;
2101 INSN_DELETED_P (insn) = 1;
2104 NEXT_INSN (prev) = next;
2106 PREV_INSN (next) = prev;
2108 set_last_insn (prev);
2110 if (GET_CODE (insn) == CODE_LABEL)
2111 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2113 /* If deleting a jump, decrement the use count of the label. Deleting
2114 the label itself should happen in the normal course of block merging. */
2115 if (GET_CODE (insn) == JUMP_INSN
2116 && JUMP_LABEL (insn)
2117 && GET_CODE (JUMP_LABEL (insn)) == CODE_LABEL)
2118 LABEL_NUSES (JUMP_LABEL (insn))--;
2120 /* Also if deleting an insn that references a label. */
2121 else if ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX
2122 && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
2123 LABEL_NUSES (XEXP (note, 0))--;
2128 /* True if a given label can be deleted. */
2131 can_delete_label_p (label)
2136 if (LABEL_PRESERVE_P (label))
2139 for (x = forced_labels; x; x = XEXP (x, 1))
2140 if (label == XEXP (x, 0))
2142 for (x = label_value_list; x; x = XEXP (x, 1))
2143 if (label == XEXP (x, 0))
2145 for (x = exception_handler_labels; x; x = XEXP (x, 1))
2146 if (label == XEXP (x, 0))
2149 /* User declared labels must be preserved. */
2150 if (LABEL_NAME (label) != 0)
2157 tail_recursion_label_p (label)
2162 for (x = tail_recursion_label_list; x; x = XEXP (x, 1))
2163 if (label == XEXP (x, 0))
2169 /* Blocks A and B are to be merged into a single block A. The insns
2170 are already contiguous, hence `nomove'. */
2173 merge_blocks_nomove (a, b)
2177 rtx b_head, b_end, a_end;
2178 rtx del_first = NULL_RTX, del_last = NULL_RTX;
2181 /* If there was a CODE_LABEL beginning B, delete it. */
2184 if (GET_CODE (b_head) == CODE_LABEL)
2186 /* Detect basic blocks with nothing but a label. This can happen
2187 in particular at the end of a function. */
2188 if (b_head == b_end)
2190 del_first = del_last = b_head;
2191 b_head = NEXT_INSN (b_head);
2194 /* Delete the basic block note. */
2195 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
2197 if (b_head == b_end)
2202 b_head = NEXT_INSN (b_head);
2205 /* If there was a jump out of A, delete it. */
2207 if (GET_CODE (a_end) == JUMP_INSN)
2211 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
2212 if (GET_CODE (prev) != NOTE
2213 || NOTE_LINE_NUMBER (prev) == NOTE_INSN_BASIC_BLOCK
2220 /* If this was a conditional jump, we need to also delete
2221 the insn that set cc0. */
2222 if (prev && sets_cc0_p (prev))
2225 prev = prev_nonnote_insn (prev);
2234 else if (GET_CODE (NEXT_INSN (a_end)) == BARRIER)
2235 del_first = NEXT_INSN (a_end);
2237 /* Delete everything marked above as well as crap that might be
2238 hanging out between the two blocks. */
2239 flow_delete_insn_chain (del_first, del_last);
2241 /* Normally there should only be one successor of A and that is B, but
2242 partway though the merge of blocks for conditional_execution we'll
2243 be merging a TEST block with THEN and ELSE successors. Free the
2244 whole lot of them and hope the caller knows what they're doing. */
2246 remove_edge (a->succ);
2248 /* Adjust the edges out of B for the new owner. */
2249 for (e = b->succ; e; e = e->succ_next)
2253 /* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */
2254 b->pred = b->succ = NULL;
2256 /* Reassociate the insns of B with A. */
2259 if (basic_block_for_insn)
2261 BLOCK_FOR_INSN (b_head) = a;
2262 while (b_head != b_end)
2264 b_head = NEXT_INSN (b_head);
2265 BLOCK_FOR_INSN (b_head) = a;
2275 /* Blocks A and B are to be merged into a single block. A has no incoming
2276 fallthru edge, so it can be moved before B without adding or modifying
2277 any jumps (aside from the jump from A to B). */
2280 merge_blocks_move_predecessor_nojumps (a, b)
2283 rtx start, end, barrier;
2289 barrier = next_nonnote_insn (end);
2290 if (GET_CODE (barrier) != BARRIER)
2292 flow_delete_insn (barrier);
2294 /* Move block and loop notes out of the chain so that we do not
2295 disturb their order.
2297 ??? A better solution would be to squeeze out all the non-nested notes
2298 and adjust the block trees appropriately. Even better would be to have
2299 a tighter connection between block trees and rtl so that this is not
2301 start = squeeze_notes (start, end);
2303 /* Scramble the insn chain. */
2304 if (end != PREV_INSN (b->head))
2305 reorder_insns (start, end, PREV_INSN (b->head));
2309 fprintf (rtl_dump_file, "Moved block %d before %d and merged.\n",
2310 a->index, b->index);
2313 /* Swap the records for the two blocks around. Although we are deleting B,
2314 A is now where B was and we want to compact the BB array from where
2316 BASIC_BLOCK (a->index) = b;
2317 BASIC_BLOCK (b->index) = a;
2319 a->index = b->index;
2322 /* Now blocks A and B are contiguous. Merge them. */
2323 merge_blocks_nomove (a, b);
2328 /* Blocks A and B are to be merged into a single block. B has no outgoing
2329 fallthru edge, so it can be moved after A without adding or modifying
2330 any jumps (aside from the jump from A to B). */
2333 merge_blocks_move_successor_nojumps (a, b)
2336 rtx start, end, barrier;
2340 barrier = NEXT_INSN (end);
2342 /* Recognize a jump table following block B. */
2343 if (GET_CODE (barrier) == CODE_LABEL
2344 && NEXT_INSN (barrier)
2345 && GET_CODE (NEXT_INSN (barrier)) == JUMP_INSN
2346 && (GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_VEC
2347 || GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_DIFF_VEC))
2349 end = NEXT_INSN (barrier);
2350 barrier = NEXT_INSN (end);
2353 /* There had better have been a barrier there. Delete it. */
2354 if (GET_CODE (barrier) != BARRIER)
2356 flow_delete_insn (barrier);
2358 /* Move block and loop notes out of the chain so that we do not
2359 disturb their order.
2361 ??? A better solution would be to squeeze out all the non-nested notes
2362 and adjust the block trees appropriately. Even better would be to have
2363 a tighter connection between block trees and rtl so that this is not
2365 start = squeeze_notes (start, end);
2367 /* Scramble the insn chain. */
2368 reorder_insns (start, end, a->end);
2370 /* Now blocks A and B are contiguous. Merge them. */
2371 merge_blocks_nomove (a, b);
2375 fprintf (rtl_dump_file, "Moved block %d after %d and merged.\n",
2376 b->index, a->index);
2382 /* Attempt to merge basic blocks that are potentially non-adjacent.
2383 Return true iff the attempt succeeded. */
2386 merge_blocks (e, b, c)
2390 /* If C has a tail recursion label, do not merge. There is no
2391 edge recorded from the call_placeholder back to this label, as
2392 that would make optimize_sibling_and_tail_recursive_calls more
2393 complex for no gain. */
2394 if (GET_CODE (c->head) == CODE_LABEL
2395 && tail_recursion_label_p (c->head))
2398 /* If B has a fallthru edge to C, no need to move anything. */
2399 if (e->flags & EDGE_FALLTHRU)
2401 merge_blocks_nomove (b, c);
2405 fprintf (rtl_dump_file, "Merged %d and %d without moving.\n",
2406 b->index, c->index);
2415 int c_has_outgoing_fallthru;
2416 int b_has_incoming_fallthru;
2418 /* We must make sure to not munge nesting of exception regions,
2419 lexical blocks, and loop notes.
2421 The first is taken care of by requiring that the active eh
2422 region at the end of one block always matches the active eh
2423 region at the beginning of the next block.
2425 The later two are taken care of by squeezing out all the notes. */
2427 /* ??? A throw/catch edge (or any abnormal edge) should be rarely
2428 executed and we may want to treat blocks which have two out
2429 edges, one normal, one abnormal as only having one edge for
2430 block merging purposes. */
2432 for (tmp_edge = c->succ; tmp_edge; tmp_edge = tmp_edge->succ_next)
2433 if (tmp_edge->flags & EDGE_FALLTHRU)
2435 c_has_outgoing_fallthru = (tmp_edge != NULL);
2437 for (tmp_edge = b->pred; tmp_edge; tmp_edge = tmp_edge->pred_next)
2438 if (tmp_edge->flags & EDGE_FALLTHRU)
2440 b_has_incoming_fallthru = (tmp_edge != NULL);
2442 /* If B does not have an incoming fallthru, and the exception regions
2443 match, then it can be moved immediately before C without introducing
2446 C can not be the first block, so we do not have to worry about
2447 accessing a non-existent block. */
2448 d = BASIC_BLOCK (c->index - 1);
2449 if (! b_has_incoming_fallthru
2450 && d->eh_end == b->eh_beg
2451 && b->eh_end == c->eh_beg)
2452 return merge_blocks_move_predecessor_nojumps (b, c);
2454 /* Otherwise, we're going to try to move C after B. Make sure the
2455 exception regions match.
2457 If B is the last basic block, then we must not try to access the
2458 block structure for block B + 1. Luckily in that case we do not
2459 need to worry about matching exception regions. */
2460 d = (b->index + 1 < n_basic_blocks ? BASIC_BLOCK (b->index + 1) : NULL);
2461 if (b->eh_end == c->eh_beg
2462 && (d == NULL || c->eh_end == d->eh_beg))
2464 /* If C does not have an outgoing fallthru, then it can be moved
2465 immediately after B without introducing or modifying jumps. */
2466 if (! c_has_outgoing_fallthru)
2467 return merge_blocks_move_successor_nojumps (b, c);
2469 /* Otherwise, we'll need to insert an extra jump, and possibly
2470 a new block to contain it. */
2471 /* ??? Not implemented yet. */
2478 /* Top level driver for merge_blocks. */
2485 /* Attempt to merge blocks as made possible by edge removal. If a block
2486 has only one successor, and the successor has only one predecessor,
2487 they may be combined. */
2489 for (i = 0; i < n_basic_blocks;)
2491 basic_block c, b = BASIC_BLOCK (i);
2494 /* A loop because chains of blocks might be combineable. */
2495 while ((s = b->succ) != NULL
2496 && s->succ_next == NULL
2497 && (s->flags & EDGE_EH) == 0
2498 && (c = s->dest) != EXIT_BLOCK_PTR
2499 && c->pred->pred_next == NULL
2500 /* If the jump insn has side effects, we can't kill the edge. */
2501 && (GET_CODE (b->end) != JUMP_INSN
2502 || onlyjump_p (b->end))
2503 && merge_blocks (s, b, c))
2506 /* Don't get confused by the index shift caused by deleting blocks. */
2511 /* The given edge should potentially be a fallthru edge. If that is in
2512 fact true, delete the jump and barriers that are in the way. */
2515 tidy_fallthru_edge (e, b, c)
2521 /* ??? In a late-running flow pass, other folks may have deleted basic
2522 blocks by nopping out blocks, leaving multiple BARRIERs between here
2523 and the target label. They ought to be chastized and fixed.
2525 We can also wind up with a sequence of undeletable labels between
2526 one block and the next.
2528 So search through a sequence of barriers, labels, and notes for
2529 the head of block C and assert that we really do fall through. */
2531 if (next_real_insn (b->end) != next_real_insn (PREV_INSN (c->head)))
2534 /* Remove what will soon cease being the jump insn from the source block.
2535 If block B consisted only of this single jump, turn it into a deleted
2538 if (GET_CODE (q) == JUMP_INSN
2540 && (any_uncondjump_p (q)
2541 || (b->succ == e && e->succ_next == NULL)))
2544 /* If this was a conditional jump, we need to also delete
2545 the insn that set cc0. */
2546 if (any_condjump_p (q) && sets_cc0_p (PREV_INSN (q)))
2553 NOTE_LINE_NUMBER (q) = NOTE_INSN_DELETED;
2554 NOTE_SOURCE_FILE (q) = 0;
2557 b->end = q = PREV_INSN (q);
2560 /* Selectively unlink the sequence. */
2561 if (q != PREV_INSN (c->head))
2562 flow_delete_insn_chain (NEXT_INSN (q), PREV_INSN (c->head));
2564 e->flags |= EDGE_FALLTHRU;
2567 /* Fix up edges that now fall through, or rather should now fall through
2568 but previously required a jump around now deleted blocks. Simplify
2569 the search by only examining blocks numerically adjacent, since this
2570 is how find_basic_blocks created them. */
2573 tidy_fallthru_edges ()
2577 for (i = 1; i < n_basic_blocks; ++i)
2579 basic_block b = BASIC_BLOCK (i - 1);
2580 basic_block c = BASIC_BLOCK (i);
2583 /* We care about simple conditional or unconditional jumps with
2586 If we had a conditional branch to the next instruction when
2587 find_basic_blocks was called, then there will only be one
2588 out edge for the block which ended with the conditional
2589 branch (since we do not create duplicate edges).
2591 Furthermore, the edge will be marked as a fallthru because we
2592 merge the flags for the duplicate edges. So we do not want to
2593 check that the edge is not a FALLTHRU edge. */
2594 if ((s = b->succ) != NULL
2595 && s->succ_next == NULL
2597 /* If the jump insn has side effects, we can't tidy the edge. */
2598 && (GET_CODE (b->end) != JUMP_INSN
2599 || onlyjump_p (b->end)))
2600 tidy_fallthru_edge (s, b, c);
2604 /* Perform data flow analysis.
2605 F is the first insn of the function; FLAGS is a set of PROP_* flags
2606 to be used in accumulating flow info. */
2609 life_analysis (f, file, flags)
2614 #ifdef ELIMINABLE_REGS
2616 static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
2619 /* Record which registers will be eliminated. We use this in
2622 CLEAR_HARD_REG_SET (elim_reg_set);
2624 #ifdef ELIMINABLE_REGS
2625 for (i = 0; i < (int) (sizeof eliminables / sizeof eliminables[0]); i++)
2626 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
2628 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
2632 flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC);
2634 /* The post-reload life analysis have (on a global basis) the same
2635 registers live as was computed by reload itself. elimination
2636 Otherwise offsets and such may be incorrect.
2638 Reload will make some registers as live even though they do not
2641 We don't want to create new auto-incs after reload, since they
2642 are unlikely to be useful and can cause problems with shared
2644 if (reload_completed)
2645 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
2647 /* We want alias analysis information for local dead store elimination. */
2648 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
2649 init_alias_analysis ();
2651 /* Always remove no-op moves. Do this before other processing so
2652 that we don't have to keep re-scanning them. */
2653 delete_noop_moves (f);
2655 /* Some targets can emit simpler epilogues if they know that sp was
2656 not ever modified during the function. After reload, of course,
2657 we've already emitted the epilogue so there's no sense searching. */
2658 if (! reload_completed)
2659 notice_stack_pointer_modification (f);
2661 /* Allocate and zero out data structures that will record the
2662 data from lifetime analysis. */
2663 allocate_reg_life_data ();
2664 allocate_bb_life_data ();
2666 /* Find the set of registers live on function exit. */
2667 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
2669 /* "Update" life info from zero. It'd be nice to begin the
2670 relaxation with just the exit and noreturn blocks, but that set
2671 is not immediately handy. */
2673 if (flags & PROP_REG_INFO)
2674 memset (regs_ever_live, 0, sizeof (regs_ever_live));
2675 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
2678 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
2679 end_alias_analysis ();
2682 dump_flow_info (file);
2684 free_basic_block_vars (1);
2687 /* A subroutine of verify_wide_reg, called through for_each_rtx.
2688 Search for REGNO. If found, abort if it is not wider than word_mode. */
2691 verify_wide_reg_1 (px, pregno)
2696 unsigned int regno = *(int *) pregno;
2698 if (GET_CODE (x) == REG && REGNO (x) == regno)
2700 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
2707 /* A subroutine of verify_local_live_at_start. Search through insns
2708 between HEAD and END looking for register REGNO. */
2711 verify_wide_reg (regno, head, end)
2718 && for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no))
2722 head = NEXT_INSN (head);
2725 /* We didn't find the register at all. Something's way screwy. */
2729 /* A subroutine of update_life_info. Verify that there are no untoward
2730 changes in live_at_start during a local update. */
2733 verify_local_live_at_start (new_live_at_start, bb)
2734 regset new_live_at_start;
2737 if (reload_completed)
2739 /* After reload, there are no pseudos, nor subregs of multi-word
2740 registers. The regsets should exactly match. */
2741 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
2748 /* Find the set of changed registers. */
2749 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
2751 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
2753 /* No registers should die. */
2754 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
2756 /* Verify that the now-live register is wider than word_mode. */
2757 verify_wide_reg (i, bb->head, bb->end);
2762 /* Updates life information starting with the basic blocks set in BLOCKS.
2763 If BLOCKS is null, consider it to be the universal set.
2765 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
2766 we are only expecting local modifications to basic blocks. If we find
2767 extra registers live at the beginning of a block, then we either killed
2768 useful data, or we have a broken split that wants data not provided.
2769 If we find registers removed from live_at_start, that means we have
2770 a broken peephole that is killing a register it shouldn't.
2772 ??? This is not true in one situation -- when a pre-reload splitter
2773 generates subregs of a multi-word pseudo, current life analysis will
2774 lose the kill. So we _can_ have a pseudo go live. How irritating.
2776 Including PROP_REG_INFO does not properly refresh regs_ever_live
2777 unless the caller resets it to zero. */
2780 update_life_info (blocks, extent, prop_flags)
2782 enum update_life_extent extent;
2786 regset_head tmp_head;
2789 tmp = INITIALIZE_REG_SET (tmp_head);
2791 /* For a global update, we go through the relaxation process again. */
2792 if (extent != UPDATE_LIFE_LOCAL)
2794 calculate_global_regs_live (blocks, blocks,
2795 prop_flags & PROP_SCAN_DEAD_CODE);
2797 /* If asked, remove notes from the blocks we'll update. */
2798 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
2799 count_or_remove_death_notes (blocks, 1);
2804 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
2806 basic_block bb = BASIC_BLOCK (i);
2808 COPY_REG_SET (tmp, bb->global_live_at_end);
2809 propagate_block (bb, tmp, (regset) NULL, prop_flags);
2811 if (extent == UPDATE_LIFE_LOCAL)
2812 verify_local_live_at_start (tmp, bb);
2817 for (i = n_basic_blocks - 1; i >= 0; --i)
2819 basic_block bb = BASIC_BLOCK (i);
2821 COPY_REG_SET (tmp, bb->global_live_at_end);
2822 propagate_block (bb, tmp, (regset) NULL, prop_flags);
2824 if (extent == UPDATE_LIFE_LOCAL)
2825 verify_local_live_at_start (tmp, bb);
2831 if (prop_flags & PROP_REG_INFO)
2833 /* The only pseudos that are live at the beginning of the function
2834 are those that were not set anywhere in the function. local-alloc
2835 doesn't know how to handle these correctly, so mark them as not
2836 local to any one basic block. */
2837 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
2838 FIRST_PSEUDO_REGISTER, i,
2839 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
2841 /* We have a problem with any pseudoreg that lives across the setjmp.
2842 ANSI says that if a user variable does not change in value between
2843 the setjmp and the longjmp, then the longjmp preserves it. This
2844 includes longjmp from a place where the pseudo appears dead.
2845 (In principle, the value still exists if it is in scope.)
2846 If the pseudo goes in a hard reg, some other value may occupy
2847 that hard reg where this pseudo is dead, thus clobbering the pseudo.
2848 Conclusion: such a pseudo must not go in a hard reg. */
2849 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
2850 FIRST_PSEUDO_REGISTER, i,
2852 if (regno_reg_rtx[i] != 0)
2854 REG_LIVE_LENGTH (i) = -1;
2855 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
2861 /* Free the variables allocated by find_basic_blocks.
2863 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
2866 free_basic_block_vars (keep_head_end_p)
2867 int keep_head_end_p;
2869 if (basic_block_for_insn)
2871 VARRAY_FREE (basic_block_for_insn);
2872 basic_block_for_insn = NULL;
2875 if (! keep_head_end_p)
2878 VARRAY_FREE (basic_block_info);
2881 ENTRY_BLOCK_PTR->aux = NULL;
2882 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
2883 EXIT_BLOCK_PTR->aux = NULL;
2884 EXIT_BLOCK_PTR->global_live_at_start = NULL;
2888 /* Return nonzero if the destination of SET equals the source. */
2894 rtx src = SET_SRC (set);
2895 rtx dst = SET_DEST (set);
2897 if (GET_CODE (src) == SUBREG && GET_CODE (dst) == SUBREG)
2899 if (SUBREG_WORD (src) != SUBREG_WORD (dst))
2901 src = SUBREG_REG (src);
2902 dst = SUBREG_REG (dst);
2905 return (GET_CODE (src) == REG && GET_CODE (dst) == REG
2906 && REGNO (src) == REGNO (dst));
2909 /* Return nonzero if an insn consists only of SETs, each of which only sets a
2916 rtx pat = PATTERN (insn);
2918 /* Insns carrying these notes are useful later on. */
2919 if (find_reg_note (insn, REG_EQUAL, NULL_RTX))
2922 if (GET_CODE (pat) == SET && set_noop_p (pat))
2925 if (GET_CODE (pat) == PARALLEL)
2928 /* If nothing but SETs of registers to themselves,
2929 this insn can also be deleted. */
2930 for (i = 0; i < XVECLEN (pat, 0); i++)
2932 rtx tem = XVECEXP (pat, 0, i);
2934 if (GET_CODE (tem) == USE
2935 || GET_CODE (tem) == CLOBBER)
2938 if (GET_CODE (tem) != SET || ! set_noop_p (tem))
2947 /* Delete any insns that copy a register to itself. */
2950 delete_noop_moves (f)
2954 for (insn = f; insn; insn = NEXT_INSN (insn))
2956 if (GET_CODE (insn) == INSN && noop_move_p (insn))
2958 PUT_CODE (insn, NOTE);
2959 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
2960 NOTE_SOURCE_FILE (insn) = 0;
2965 /* Determine if the stack pointer is constant over the life of the function.
2966 Only useful before prologues have been emitted. */
2969 notice_stack_pointer_modification_1 (x, pat, data)
2971 rtx pat ATTRIBUTE_UNUSED;
2972 void *data ATTRIBUTE_UNUSED;
2974 if (x == stack_pointer_rtx
2975 /* The stack pointer is only modified indirectly as the result
2976 of a push until later in flow. See the comments in rtl.texi
2977 regarding Embedded Side-Effects on Addresses. */
2978 || (GET_CODE (x) == MEM
2979 && (GET_CODE (XEXP (x, 0)) == PRE_DEC
2980 || GET_CODE (XEXP (x, 0)) == PRE_INC
2981 || GET_CODE (XEXP (x, 0)) == POST_DEC
2982 || GET_CODE (XEXP (x, 0)) == POST_INC)
2983 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
2984 current_function_sp_is_unchanging = 0;
2988 notice_stack_pointer_modification (f)
2993 /* Assume that the stack pointer is unchanging if alloca hasn't
2995 current_function_sp_is_unchanging = !current_function_calls_alloca;
2996 if (! current_function_sp_is_unchanging)
2999 for (insn = f; insn; insn = NEXT_INSN (insn))
3003 /* Check if insn modifies the stack pointer. */
3004 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
3006 if (! current_function_sp_is_unchanging)
3012 /* Mark a register in SET. Hard registers in large modes get all
3013 of their component registers set as well. */
3016 mark_reg (reg, xset)
3020 regset set = (regset) xset;
3021 int regno = REGNO (reg);
3023 if (GET_MODE (reg) == BLKmode)
3026 SET_REGNO_REG_SET (set, regno);
3027 if (regno < FIRST_PSEUDO_REGISTER)
3029 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
3031 SET_REGNO_REG_SET (set, regno + n);
3035 /* Mark those regs which are needed at the end of the function as live
3036 at the end of the last basic block. */
3039 mark_regs_live_at_end (set)
3044 /* If exiting needs the right stack value, consider the stack pointer
3045 live at the end of the function. */
3046 if ((HAVE_epilogue && reload_completed)
3047 || ! EXIT_IGNORE_STACK
3048 || (! FRAME_POINTER_REQUIRED
3049 && ! current_function_calls_alloca
3050 && flag_omit_frame_pointer)
3051 || current_function_sp_is_unchanging)
3053 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
3056 /* Mark the frame pointer if needed at the end of the function. If
3057 we end up eliminating it, it will be removed from the live list
3058 of each basic block by reload. */
3060 if (! reload_completed || frame_pointer_needed)
3062 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
3063 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3064 /* If they are different, also mark the hard frame pointer as live. */
3065 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
3066 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
3070 #ifdef PIC_OFFSET_TABLE_REGNUM
3071 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
3072 /* Many architectures have a GP register even without flag_pic.
3073 Assume the pic register is not in use, or will be handled by
3074 other means, if it is not fixed. */
3075 if (fixed_regs[PIC_OFFSET_TABLE_REGNUM])
3076 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
3080 /* Mark all global registers, and all registers used by the epilogue
3081 as being live at the end of the function since they may be
3082 referenced by our caller. */
3083 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3084 if (global_regs[i] || EPILOGUE_USES (i))
3085 SET_REGNO_REG_SET (set, i);
3087 /* Mark all call-saved registers that we actaully used. */
3088 if (HAVE_epilogue && reload_completed)
3090 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3091 if (regs_ever_live[i] && ! call_used_regs[i] && ! LOCAL_REGNO (i))
3092 SET_REGNO_REG_SET (set, i);
3095 /* Mark function return value. */
3096 diddle_return_value (mark_reg, set);
3099 /* Callback function for for_each_successor_phi. DATA is a regset.
3100 Sets the SRC_REGNO, the regno of the phi alternative for phi node
3101 INSN, in the regset. */
3104 set_phi_alternative_reg (insn, dest_regno, src_regno, data)
3105 rtx insn ATTRIBUTE_UNUSED;
3106 int dest_regno ATTRIBUTE_UNUSED;
3110 regset live = (regset) data;
3111 SET_REGNO_REG_SET (live, src_regno);
3115 /* Propagate global life info around the graph of basic blocks. Begin
3116 considering blocks with their corresponding bit set in BLOCKS_IN.
3117 If BLOCKS_IN is null, consider it the universal set.
3119 BLOCKS_OUT is set for every block that was changed. */
3122 calculate_global_regs_live (blocks_in, blocks_out, flags)
3123 sbitmap blocks_in, blocks_out;
3126 basic_block *queue, *qhead, *qtail, *qend;
3127 regset tmp, new_live_at_end;
3128 regset_head tmp_head;
3129 regset_head new_live_at_end_head;
3132 tmp = INITIALIZE_REG_SET (tmp_head);
3133 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
3135 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
3136 because the `head == tail' style test for an empty queue doesn't
3137 work with a full queue. */
3138 queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
3140 qhead = qend = queue + n_basic_blocks + 2;
3142 /* Clear out the garbage that might be hanging out in bb->aux. */
3143 for (i = n_basic_blocks - 1; i >= 0; --i)
3144 BASIC_BLOCK (i)->aux = NULL;
3146 /* Queue the blocks set in the initial mask. Do this in reverse block
3147 number order so that we are more likely for the first round to do
3148 useful work. We use AUX non-null to flag that the block is queued. */
3151 EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
3153 basic_block bb = BASIC_BLOCK (i);
3160 for (i = 0; i < n_basic_blocks; ++i)
3162 basic_block bb = BASIC_BLOCK (i);
3169 sbitmap_zero (blocks_out);
3171 while (qhead != qtail)
3173 int rescan, changed;
3182 /* Begin by propogating live_at_start from the successor blocks. */
3183 CLEAR_REG_SET (new_live_at_end);
3184 for (e = bb->succ; e; e = e->succ_next)
3186 basic_block sb = e->dest;
3187 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
3190 /* Force the stack pointer to be live -- which might not already be
3191 the case for blocks within infinite loops. */
3192 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
3194 /* Regs used in phi nodes are not included in
3195 global_live_at_start, since they are live only along a
3196 particular edge. Set those regs that are live because of a
3197 phi node alternative corresponding to this particular block. */
3199 for_each_successor_phi (bb, &set_phi_alternative_reg,
3202 if (bb == ENTRY_BLOCK_PTR)
3204 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3208 /* On our first pass through this block, we'll go ahead and continue.
3209 Recognize first pass by local_set NULL. On subsequent passes, we
3210 get to skip out early if live_at_end wouldn't have changed. */
3212 if (bb->local_set == NULL)
3214 bb->local_set = OBSTACK_ALLOC_REG_SET (function_obstack);
3219 /* If any bits were removed from live_at_end, we'll have to
3220 rescan the block. This wouldn't be necessary if we had
3221 precalculated local_live, however with PROP_SCAN_DEAD_CODE
3222 local_live is really dependent on live_at_end. */
3223 CLEAR_REG_SET (tmp);
3224 rescan = bitmap_operation (tmp, bb->global_live_at_end,
3225 new_live_at_end, BITMAP_AND_COMPL);
3229 /* Find the set of changed bits. Take this opportunity
3230 to notice that this set is empty and early out. */
3231 CLEAR_REG_SET (tmp);
3232 changed = bitmap_operation (tmp, bb->global_live_at_end,
3233 new_live_at_end, BITMAP_XOR);
3237 /* If any of the changed bits overlap with local_set,
3238 we'll have to rescan the block. Detect overlap by
3239 the AND with ~local_set turning off bits. */
3240 rescan = bitmap_operation (tmp, tmp, bb->local_set,
3245 /* Let our caller know that BB changed enough to require its
3246 death notes updated. */
3248 SET_BIT (blocks_out, bb->index);
3252 /* Add to live_at_start the set of all registers in
3253 new_live_at_end that aren't in the old live_at_end. */
3255 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
3257 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3259 changed = bitmap_operation (bb->global_live_at_start,
3260 bb->global_live_at_start,
3267 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3269 /* Rescan the block insn by insn to turn (a copy of) live_at_end
3270 into live_at_start. */
3271 propagate_block (bb, new_live_at_end, bb->local_set, flags);
3273 /* If live_at start didn't change, no need to go farther. */
3274 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
3277 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
3280 /* Queue all predecessors of BB so that we may re-examine
3281 their live_at_end. */
3282 for (e = bb->pred; e; e = e->pred_next)
3284 basic_block pb = e->src;
3285 if (pb->aux == NULL)
3296 FREE_REG_SET (new_live_at_end);
3300 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
3302 basic_block bb = BASIC_BLOCK (i);
3303 FREE_REG_SET (bb->local_set);
3308 for (i = n_basic_blocks - 1; i >= 0; --i)
3310 basic_block bb = BASIC_BLOCK (i);
3311 FREE_REG_SET (bb->local_set);
3318 /* Subroutines of life analysis. */
3320 /* Allocate the permanent data structures that represent the results
3321 of life analysis. Not static since used also for stupid life analysis. */
3324 allocate_bb_life_data ()
3328 for (i = 0; i < n_basic_blocks; i++)
3330 basic_block bb = BASIC_BLOCK (i);
3332 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (function_obstack);
3333 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (function_obstack);
3336 ENTRY_BLOCK_PTR->global_live_at_end
3337 = OBSTACK_ALLOC_REG_SET (function_obstack);
3338 EXIT_BLOCK_PTR->global_live_at_start
3339 = OBSTACK_ALLOC_REG_SET (function_obstack);
3341 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (function_obstack);
3345 allocate_reg_life_data ()
3349 max_regno = max_reg_num ();
3351 /* Recalculate the register space, in case it has grown. Old style
3352 vector oriented regsets would set regset_{size,bytes} here also. */
3353 allocate_reg_info (max_regno, FALSE, FALSE);
3355 /* Reset all the data we'll collect in propagate_block and its
3357 for (i = 0; i < max_regno; i++)
3361 REG_N_DEATHS (i) = 0;
3362 REG_N_CALLS_CROSSED (i) = 0;
3363 REG_LIVE_LENGTH (i) = 0;
3364 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
3368 /* Delete dead instructions for propagate_block. */
3371 propagate_block_delete_insn (bb, insn)
3375 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
3377 /* If the insn referred to a label, and that label was attached to
3378 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
3379 pretty much mandatory to delete it, because the ADDR_VEC may be
3380 referencing labels that no longer exist. */
3384 rtx label = XEXP (inote, 0);
3387 if (LABEL_NUSES (label) == 1
3388 && (next = next_nonnote_insn (label)) != NULL
3389 && GET_CODE (next) == JUMP_INSN
3390 && (GET_CODE (PATTERN (next)) == ADDR_VEC
3391 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
3393 rtx pat = PATTERN (next);
3394 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
3395 int len = XVECLEN (pat, diff_vec_p);
3398 for (i = 0; i < len; i++)
3399 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
3401 flow_delete_insn (next);
3405 if (bb->end == insn)
3406 bb->end = PREV_INSN (insn);
3407 flow_delete_insn (insn);
3410 /* Delete dead libcalls for propagate_block. Return the insn
3411 before the libcall. */
3414 propagate_block_delete_libcall (bb, insn, note)
3418 rtx first = XEXP (note, 0);
3419 rtx before = PREV_INSN (first);
3421 if (insn == bb->end)
3424 flow_delete_insn_chain (first, insn);
3428 /* Update the life-status of regs for one insn. Return the previous insn. */
3431 propagate_one_insn (pbi, insn)
3432 struct propagate_block_info *pbi;
3435 rtx prev = PREV_INSN (insn);
3436 int flags = pbi->flags;
3437 int insn_is_dead = 0;
3438 int libcall_is_dead = 0;
3442 if (! INSN_P (insn))
3445 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
3446 if (flags & PROP_SCAN_DEAD_CODE)
3448 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0,
3450 libcall_is_dead = (insn_is_dead && note != 0
3451 && libcall_dead_p (pbi, note, insn));
3454 /* We almost certainly don't want to delete prologue or epilogue
3455 instructions. Warn about probable compiler losage. */
3458 && (((HAVE_epilogue || HAVE_prologue)
3459 && prologue_epilogue_contains (insn))
3460 || (HAVE_sibcall_epilogue
3461 && sibcall_epilogue_contains (insn)))
3462 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
3464 if (flags & PROP_KILL_DEAD_CODE)
3466 warning ("ICE: would have deleted prologue/epilogue insn");
3467 if (!inhibit_warnings)
3470 libcall_is_dead = insn_is_dead = 0;
3473 /* If an instruction consists of just dead store(s) on final pass,
3475 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
3477 /* Record sets. Do this even for dead instructions, since they
3478 would have killed the values if they hadn't been deleted. */
3479 mark_set_regs (pbi, PATTERN (insn), insn);
3481 /* CC0 is now known to be dead. Either this insn used it,
3482 in which case it doesn't anymore, or clobbered it,
3483 so the next insn can't use it. */
3486 if (libcall_is_dead)
3488 prev = propagate_block_delete_libcall (pbi->bb, insn, note);
3489 insn = NEXT_INSN (prev);
3492 propagate_block_delete_insn (pbi->bb, insn);
3497 /* See if this is an increment or decrement that can be merged into
3498 a following memory address. */
3501 register rtx x = single_set (insn);
3503 /* Does this instruction increment or decrement a register? */
3504 if ((flags & PROP_AUTOINC)
3506 && GET_CODE (SET_DEST (x)) == REG
3507 && (GET_CODE (SET_SRC (x)) == PLUS
3508 || GET_CODE (SET_SRC (x)) == MINUS)
3509 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
3510 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
3511 /* Ok, look for a following memory ref we can combine with.
3512 If one is found, change the memory ref to a PRE_INC
3513 or PRE_DEC, cancel this insn, and return 1.
3514 Return 0 if nothing has been done. */
3515 && try_pre_increment_1 (pbi, insn))
3518 #endif /* AUTO_INC_DEC */
3520 CLEAR_REG_SET (pbi->new_set);
3522 /* If this is not the final pass, and this insn is copying the value of
3523 a library call and it's dead, don't scan the insns that perform the
3524 library call, so that the call's arguments are not marked live. */
3525 if (libcall_is_dead)
3527 /* Record the death of the dest reg. */
3528 mark_set_regs (pbi, PATTERN (insn), insn);
3530 insn = XEXP (note, 0);
3531 return PREV_INSN (insn);
3533 else if (GET_CODE (PATTERN (insn)) == SET
3534 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
3535 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
3536 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
3537 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
3538 /* We have an insn to pop a constant amount off the stack.
3539 (Such insns use PLUS regardless of the direction of the stack,
3540 and any insn to adjust the stack by a constant is always a pop.)
3541 These insns, if not dead stores, have no effect on life. */
3545 /* Any regs live at the time of a call instruction must not go
3546 in a register clobbered by calls. Find all regs now live and
3547 record this for them. */
3549 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
3550 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
3551 { REG_N_CALLS_CROSSED (i)++; });
3553 /* Record sets. Do this even for dead instructions, since they
3554 would have killed the values if they hadn't been deleted. */
3555 mark_set_regs (pbi, PATTERN (insn), insn);
3557 if (GET_CODE (insn) == CALL_INSN)
3563 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
3564 cond = COND_EXEC_TEST (PATTERN (insn));
3566 /* Non-constant calls clobber memory. */
3567 if (! CONST_CALL_P (insn))
3568 free_EXPR_LIST_list (&pbi->mem_set_list);
3570 /* There may be extra registers to be clobbered. */
3571 for (note = CALL_INSN_FUNCTION_USAGE (insn);
3573 note = XEXP (note, 1))
3574 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
3575 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
3576 cond, insn, pbi->flags);
3578 /* Calls change all call-used and global registers. */
3579 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3580 if (call_used_regs[i] && ! global_regs[i]
3583 /* We do not want REG_UNUSED notes for these registers. */
3584 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
3586 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
3590 /* If an insn doesn't use CC0, it becomes dead since we assume
3591 that every insn clobbers it. So show it dead here;
3592 mark_used_regs will set it live if it is referenced. */
3597 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
3599 /* Sometimes we may have inserted something before INSN (such as a move)
3600 when we make an auto-inc. So ensure we will scan those insns. */
3602 prev = PREV_INSN (insn);
3605 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
3611 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
3612 cond = COND_EXEC_TEST (PATTERN (insn));
3614 /* Calls use their arguments. */
3615 for (note = CALL_INSN_FUNCTION_USAGE (insn);
3617 note = XEXP (note, 1))
3618 if (GET_CODE (XEXP (note, 0)) == USE)
3619 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
3622 /* The stack ptr is used (honorarily) by a CALL insn. */
3623 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
3625 /* Calls may also reference any of the global registers,
3626 so they are made live. */
3627 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3629 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
3634 /* On final pass, update counts of how many insns in which each reg
3636 if (flags & PROP_REG_INFO)
3637 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
3638 { REG_LIVE_LENGTH (i)++; });
3643 /* Initialize a propagate_block_info struct for public consumption.
3644 Note that the structure itself is opaque to this file, but that
3645 the user can use the regsets provided here. */
3647 struct propagate_block_info *
3648 init_propagate_block_info (bb, live, local_set, flags)
3654 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
3657 pbi->reg_live = live;
3658 pbi->mem_set_list = NULL_RTX;
3659 pbi->local_set = local_set;
3663 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
3664 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
3666 pbi->reg_next_use = NULL;
3668 pbi->new_set = BITMAP_XMALLOC ();
3670 #ifdef HAVE_conditional_execution
3671 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
3672 free_reg_cond_life_info);
3673 pbi->reg_cond_reg = BITMAP_XMALLOC ();
3675 /* If this block ends in a conditional branch, for each register live
3676 from one side of the branch and not the other, record the register
3677 as conditionally dead. */
3678 if ((flags & (PROP_DEATH_NOTES | PROP_SCAN_DEAD_CODE))
3679 && GET_CODE (bb->end) == JUMP_INSN
3680 && any_condjump_p (bb->end))
3682 regset_head diff_head;
3683 regset diff = INITIALIZE_REG_SET (diff_head);
3684 basic_block bb_true, bb_false;
3685 rtx cond_true, cond_false, set_src;
3688 /* Identify the successor blocks. */
3689 bb_true = bb->succ->dest;
3690 if (bb->succ->succ_next != NULL)
3692 bb_false = bb->succ->succ_next->dest;
3694 if (bb->succ->flags & EDGE_FALLTHRU)
3696 basic_block t = bb_false;
3700 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
3705 /* This can happen with a conditional jump to the next insn. */
3706 if (JUMP_LABEL (bb->end) != bb_true->head)
3709 /* Simplest way to do nothing. */
3713 /* Extract the condition from the branch. */
3714 set_src = SET_SRC (pc_set (bb->end));
3715 cond_true = XEXP (set_src, 0);
3716 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
3717 GET_MODE (cond_true), XEXP (cond_true, 0),
3718 XEXP (cond_true, 1));
3719 if (GET_CODE (XEXP (set_src, 1)) == PC)
3722 cond_false = cond_true;
3726 /* Compute which register lead different lives in the successors. */
3727 if (bitmap_operation (diff, bb_true->global_live_at_start,
3728 bb_false->global_live_at_start, BITMAP_XOR))
3730 rtx reg = XEXP (cond_true, 0);
3732 if (GET_CODE (reg) == SUBREG)
3733 reg = SUBREG_REG (reg);
3735 if (GET_CODE (reg) != REG)
3738 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
3740 /* For each such register, mark it conditionally dead. */
3741 EXECUTE_IF_SET_IN_REG_SET
3744 struct reg_cond_life_info *rcli;
3747 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
3749 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
3753 rcli->condition = alloc_EXPR_LIST (0, cond, NULL_RTX);
3755 splay_tree_insert (pbi->reg_cond_dead, i,
3756 (splay_tree_value) rcli);
3760 FREE_REG_SET (diff);
3764 /* If this block has no successors, any stores to the frame that aren't
3765 used later in the block are dead. So make a pass over the block
3766 recording any such that are made and show them dead at the end. We do
3767 a very conservative and simple job here. */
3769 && (flags & PROP_SCAN_DEAD_CODE)
3770 && (bb->succ == NULL
3771 || (bb->succ->succ_next == NULL
3772 && bb->succ->dest == EXIT_BLOCK_PTR)))
3775 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
3776 if (GET_CODE (insn) == INSN
3777 && GET_CODE (PATTERN (insn)) == SET
3778 && GET_CODE (SET_DEST (PATTERN (insn))) == MEM)
3780 rtx mem = SET_DEST (PATTERN (insn));
3782 if (XEXP (mem, 0) == frame_pointer_rtx
3783 || (GET_CODE (XEXP (mem, 0)) == PLUS
3784 && XEXP (XEXP (mem, 0), 0) == frame_pointer_rtx
3785 && GET_CODE (XEXP (XEXP (mem, 0), 1)) == CONST_INT))
3786 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
3793 /* Release a propagate_block_info struct. */
3796 free_propagate_block_info (pbi)
3797 struct propagate_block_info *pbi;
3799 free_EXPR_LIST_list (&pbi->mem_set_list);
3801 BITMAP_XFREE (pbi->new_set);
3803 #ifdef HAVE_conditional_execution
3804 splay_tree_delete (pbi->reg_cond_dead);
3805 BITMAP_XFREE (pbi->reg_cond_reg);
3808 if (pbi->reg_next_use)
3809 free (pbi->reg_next_use);
3814 /* Compute the registers live at the beginning of a basic block BB from
3815 those live at the end.
3817 When called, REG_LIVE contains those live at the end. On return, it
3818 contains those live at the beginning.
3820 LOCAL_SET, if non-null, will be set with all registers killed by
3821 this basic block. */
3824 propagate_block (bb, live, local_set, flags)
3830 struct propagate_block_info *pbi;
3833 pbi = init_propagate_block_info (bb, live, local_set, flags);
3835 if (flags & PROP_REG_INFO)
3839 /* Process the regs live at the end of the block.
3840 Mark them as not local to any one basic block. */
3841 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
3842 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
3845 /* Scan the block an insn at a time from end to beginning. */
3847 for (insn = bb->end;; insn = prev)
3849 /* If this is a call to `setjmp' et al, warn if any
3850 non-volatile datum is live. */
3851 if ((flags & PROP_REG_INFO)
3852 && GET_CODE (insn) == NOTE
3853 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
3854 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
3856 prev = propagate_one_insn (pbi, insn);
3858 if (insn == bb->head)
3862 free_propagate_block_info (pbi);
3865 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
3866 (SET expressions whose destinations are registers dead after the insn).
3867 NEEDED is the regset that says which regs are alive after the insn.
3869 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
3871 If X is the entire body of an insn, NOTES contains the reg notes
3872 pertaining to the insn. */
3875 insn_dead_p (pbi, x, call_ok, notes)
3876 struct propagate_block_info *pbi;
3879 rtx notes ATTRIBUTE_UNUSED;
3881 enum rtx_code code = GET_CODE (x);
3884 /* If flow is invoked after reload, we must take existing AUTO_INC
3885 expresions into account. */
3886 if (reload_completed)
3888 for (; notes; notes = XEXP (notes, 1))
3890 if (REG_NOTE_KIND (notes) == REG_INC)
3892 int regno = REGNO (XEXP (notes, 0));
3894 /* Don't delete insns to set global regs. */
3895 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
3896 || REGNO_REG_SET_P (pbi->reg_live, regno))
3903 /* If setting something that's a reg or part of one,
3904 see if that register's altered value will be live. */
3908 rtx r = SET_DEST (x);
3911 if (GET_CODE (r) == CC0)
3912 return ! pbi->cc0_live;
3915 /* A SET that is a subroutine call cannot be dead. */
3916 if (GET_CODE (SET_SRC (x)) == CALL)
3922 /* Don't eliminate loads from volatile memory or volatile asms. */
3923 else if (volatile_refs_p (SET_SRC (x)))
3926 if (GET_CODE (r) == MEM)
3930 if (MEM_VOLATILE_P (r))
3933 /* Walk the set of memory locations we are currently tracking
3934 and see if one is an identical match to this memory location.
3935 If so, this memory write is dead (remember, we're walking
3936 backwards from the end of the block to the start). */
3937 temp = pbi->mem_set_list;
3940 if (rtx_equal_p (XEXP (temp, 0), r))
3942 temp = XEXP (temp, 1);
3947 while (GET_CODE (r) == SUBREG
3948 || GET_CODE (r) == STRICT_LOW_PART
3949 || GET_CODE (r) == ZERO_EXTRACT)
3952 if (GET_CODE (r) == REG)
3954 int regno = REGNO (r);
3957 if (REGNO_REG_SET_P (pbi->reg_live, regno))
3960 /* If this is a hard register, verify that subsequent
3961 words are not needed. */
3962 if (regno < FIRST_PSEUDO_REGISTER)
3964 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
3967 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
3971 /* Don't delete insns to set global regs. */
3972 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
3975 /* Make sure insns to set the stack pointer aren't deleted. */
3976 if (regno == STACK_POINTER_REGNUM)
3979 /* Make sure insns to set the frame pointer aren't deleted. */
3980 if (regno == FRAME_POINTER_REGNUM
3981 && (! reload_completed || frame_pointer_needed))
3983 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3984 if (regno == HARD_FRAME_POINTER_REGNUM
3985 && (! reload_completed || frame_pointer_needed))
3989 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3990 /* Make sure insns to set arg pointer are never deleted
3991 (if the arg pointer isn't fixed, there will be a USE
3992 for it, so we can treat it normally). */
3993 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
3997 #ifdef PIC_OFFSET_TABLE_REGNUM
3998 /* Before reload, do not allow sets of the pic register
3999 to be deleted. Reload can insert references to
4000 constant pool memory anywhere in the function, making
4001 the PIC register live where it wasn't before. */
4002 if (regno == PIC_OFFSET_TABLE_REGNUM && fixed_regs[regno]
4003 && ! reload_completed)
4007 /* Otherwise, the set is dead. */
4013 /* If performing several activities, insn is dead if each activity
4014 is individually dead. Also, CLOBBERs and USEs can be ignored; a
4015 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
4017 else if (code == PARALLEL)
4019 int i = XVECLEN (x, 0);
4021 for (i--; i >= 0; i--)
4022 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
4023 && GET_CODE (XVECEXP (x, 0, i)) != USE
4024 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
4030 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
4031 is not necessarily true for hard registers. */
4032 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
4033 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
4034 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
4037 /* We do not check other CLOBBER or USE here. An insn consisting of just
4038 a CLOBBER or just a USE should not be deleted. */
4042 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
4043 return 1 if the entire library call is dead.
4044 This is true if INSN copies a register (hard or pseudo)
4045 and if the hard return reg of the call insn is dead.
4046 (The caller should have tested the destination of the SET inside
4047 INSN already for death.)
4049 If this insn doesn't just copy a register, then we don't
4050 have an ordinary libcall. In that case, cse could not have
4051 managed to substitute the source for the dest later on,
4052 so we can assume the libcall is dead.
4054 PBI is the block info giving pseudoregs live before this insn.
4055 NOTE is the REG_RETVAL note of the insn. */
4058 libcall_dead_p (pbi, note, insn)
4059 struct propagate_block_info *pbi;
4063 rtx x = single_set (insn);
4067 register rtx r = SET_SRC (x);
4068 if (GET_CODE (r) == REG)
4070 rtx call = XEXP (note, 0);
4074 /* Find the call insn. */
4075 while (call != insn && GET_CODE (call) != CALL_INSN)
4076 call = NEXT_INSN (call);
4078 /* If there is none, do nothing special,
4079 since ordinary death handling can understand these insns. */
4083 /* See if the hard reg holding the value is dead.
4084 If this is a PARALLEL, find the call within it. */
4085 call_pat = PATTERN (call);
4086 if (GET_CODE (call_pat) == PARALLEL)
4088 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
4089 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
4090 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
4093 /* This may be a library call that is returning a value
4094 via invisible pointer. Do nothing special, since
4095 ordinary death handling can understand these insns. */
4099 call_pat = XVECEXP (call_pat, 0, i);
4102 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
4108 /* Return 1 if register REGNO was used before it was set, i.e. if it is
4109 live at function entry. Don't count global register variables, variables
4110 in registers that can be used for function arg passing, or variables in
4111 fixed hard registers. */
4114 regno_uninitialized (regno)
4117 if (n_basic_blocks == 0
4118 || (regno < FIRST_PSEUDO_REGISTER
4119 && (global_regs[regno]
4120 || fixed_regs[regno]
4121 || FUNCTION_ARG_REGNO_P (regno))))
4124 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
4127 /* 1 if register REGNO was alive at a place where `setjmp' was called
4128 and was set more than once or is an argument.
4129 Such regs may be clobbered by `longjmp'. */
4132 regno_clobbered_at_setjmp (regno)
4135 if (n_basic_blocks == 0)
4138 return ((REG_N_SETS (regno) > 1
4139 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
4140 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
4143 /* INSN references memory, possibly using autoincrement addressing modes.
4144 Find any entries on the mem_set_list that need to be invalidated due
4145 to an address change. */
4148 invalidate_mems_from_autoinc (pbi, insn)
4149 struct propagate_block_info *pbi;
4152 rtx note = REG_NOTES (insn);
4153 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
4155 if (REG_NOTE_KIND (note) == REG_INC)
4157 rtx temp = pbi->mem_set_list;
4158 rtx prev = NULL_RTX;
4163 next = XEXP (temp, 1);
4164 if (reg_overlap_mentioned_p (XEXP (note, 0), XEXP (temp, 0)))
4166 /* Splice temp out of list. */
4168 XEXP (prev, 1) = next;
4170 pbi->mem_set_list = next;
4171 free_EXPR_LIST_node (temp);
4181 /* Process the registers that are set within X. Their bits are set to
4182 1 in the regset DEAD, because they are dead prior to this insn.
4184 If INSN is nonzero, it is the insn being processed.
4186 FLAGS is the set of operations to perform. */
4189 mark_set_regs (pbi, x, insn)
4190 struct propagate_block_info *pbi;
4193 rtx cond = NULL_RTX;
4198 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
4200 if (REG_NOTE_KIND (link) == REG_INC)
4201 mark_set_1 (pbi, SET, XEXP (link, 0),
4202 (GET_CODE (x) == COND_EXEC
4203 ? COND_EXEC_TEST (x) : NULL_RTX),
4207 switch (code = GET_CODE (x))
4211 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
4215 cond = COND_EXEC_TEST (x);
4216 x = COND_EXEC_CODE (x);
4222 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
4224 rtx sub = XVECEXP (x, 0, i);
4225 switch (code = GET_CODE (sub))
4228 if (cond != NULL_RTX)
4231 cond = COND_EXEC_TEST (sub);
4232 sub = COND_EXEC_CODE (sub);
4233 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
4239 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
4254 /* Process a single SET rtx, X. */
4257 mark_set_1 (pbi, code, reg, cond, insn, flags)
4258 struct propagate_block_info *pbi;
4260 rtx reg, cond, insn;
4263 int regno_first = -1, regno_last = -1;
4267 /* Some targets place small structures in registers for
4268 return values of functions. We have to detect this
4269 case specially here to get correct flow information. */
4270 if (GET_CODE (reg) == PARALLEL
4271 && GET_MODE (reg) == BLKmode)
4273 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
4274 mark_set_1 (pbi, code, XVECEXP (reg, 0, i), cond, insn, flags);
4278 /* Modifying just one hardware register of a multi-reg value or just a
4279 byte field of a register does not mean the value from before this insn
4280 is now dead. Of course, if it was dead after it's unused now. */
4282 switch (GET_CODE (reg))
4286 case STRICT_LOW_PART:
4287 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
4289 reg = XEXP (reg, 0);
4290 while (GET_CODE (reg) == SUBREG
4291 || GET_CODE (reg) == ZERO_EXTRACT
4292 || GET_CODE (reg) == SIGN_EXTRACT
4293 || GET_CODE (reg) == STRICT_LOW_PART);
4294 if (GET_CODE (reg) == MEM)
4296 not_dead = REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
4300 regno_last = regno_first = REGNO (reg);
4301 if (regno_first < FIRST_PSEUDO_REGISTER)
4302 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
4306 if (GET_CODE (SUBREG_REG (reg)) == REG)
4308 enum machine_mode outer_mode = GET_MODE (reg);
4309 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
4311 /* Identify the range of registers affected. This is moderately
4312 tricky for hard registers. See alter_subreg. */
4314 regno_last = regno_first = REGNO (SUBREG_REG (reg));
4315 if (regno_first < FIRST_PSEUDO_REGISTER)
4317 #ifdef ALTER_HARD_SUBREG
4318 regno_first = ALTER_HARD_SUBREG (outer_mode, SUBREG_WORD (reg),
4319 inner_mode, regno_first);
4321 regno_first += SUBREG_WORD (reg);
4323 regno_last = (regno_first
4324 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
4326 /* Since we've just adjusted the register number ranges, make
4327 sure REG matches. Otherwise some_was_live will be clear
4328 when it shouldn't have been, and we'll create incorrect
4329 REG_UNUSED notes. */
4330 reg = gen_rtx_REG (outer_mode, regno_first);
4334 /* If the number of words in the subreg is less than the number
4335 of words in the full register, we have a well-defined partial
4336 set. Otherwise the high bits are undefined.
4338 This is only really applicable to pseudos, since we just took
4339 care of multi-word hard registers. */
4340 if (((GET_MODE_SIZE (outer_mode)
4341 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
4342 < ((GET_MODE_SIZE (inner_mode)
4343 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
4344 not_dead = REGNO_REG_SET_P (pbi->reg_live, regno_first);
4346 reg = SUBREG_REG (reg);
4350 reg = SUBREG_REG (reg);
4357 /* If this set is a MEM, then it kills any aliased writes.
4358 If this set is a REG, then it kills any MEMs which use the reg. */
4359 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
4361 if (GET_CODE (reg) == MEM || GET_CODE (reg) == REG)
4363 rtx temp = pbi->mem_set_list;
4364 rtx prev = NULL_RTX;
4369 next = XEXP (temp, 1);
4370 if ((GET_CODE (reg) == MEM
4371 && output_dependence (XEXP (temp, 0), reg))
4372 || (GET_CODE (reg) == REG
4373 && reg_overlap_mentioned_p (reg, XEXP (temp, 0))))
4375 /* Splice this entry out of the list. */
4377 XEXP (prev, 1) = next;
4379 pbi->mem_set_list = next;
4380 free_EXPR_LIST_node (temp);
4388 /* If the memory reference had embedded side effects (autoincrement
4389 address modes. Then we may need to kill some entries on the
4391 if (insn && GET_CODE (reg) == MEM)
4392 invalidate_mems_from_autoinc (pbi, insn);
4394 if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
4395 /* ??? With more effort we could track conditional memory life. */
4397 /* We do not know the size of a BLKmode store, so we do not track
4398 them for redundant store elimination. */
4399 && GET_MODE (reg) != BLKmode
4400 /* There are no REG_INC notes for SP, so we can't assume we'll see
4401 everything that invalidates it. To be safe, don't eliminate any
4402 stores though SP; none of them should be redundant anyway. */
4403 && ! reg_mentioned_p (stack_pointer_rtx, reg))
4404 pbi->mem_set_list = alloc_EXPR_LIST (0, reg, pbi->mem_set_list);
4407 if (GET_CODE (reg) == REG
4408 && ! (regno_first == FRAME_POINTER_REGNUM
4409 && (! reload_completed || frame_pointer_needed))
4410 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4411 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
4412 && (! reload_completed || frame_pointer_needed))
4414 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4415 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
4419 int some_was_live = 0, some_was_dead = 0;
4421 for (i = regno_first; i <= regno_last; ++i)
4423 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
4425 SET_REGNO_REG_SET (pbi->local_set, i);
4426 if (code != CLOBBER)
4427 SET_REGNO_REG_SET (pbi->new_set, i);
4429 some_was_live |= needed_regno;
4430 some_was_dead |= ! needed_regno;
4433 #ifdef HAVE_conditional_execution
4434 /* Consider conditional death in deciding that the register needs
4436 if (some_was_live && ! not_dead
4437 /* The stack pointer is never dead. Well, not strictly true,
4438 but it's very difficult to tell from here. Hopefully
4439 combine_stack_adjustments will fix up the most egregious
4441 && regno_first != STACK_POINTER_REGNUM)
4443 for (i = regno_first; i <= regno_last; ++i)
4444 if (! mark_regno_cond_dead (pbi, i, cond))
4449 /* Additional data to record if this is the final pass. */
4450 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
4451 | PROP_DEATH_NOTES | PROP_AUTOINC))
4454 register int blocknum = pbi->bb->index;
4457 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4459 y = pbi->reg_next_use[regno_first];
4461 /* The next use is no longer next, since a store intervenes. */
4462 for (i = regno_first; i <= regno_last; ++i)
4463 pbi->reg_next_use[i] = 0;
4466 if (flags & PROP_REG_INFO)
4468 for (i = regno_first; i <= regno_last; ++i)
4470 /* Count (weighted) references, stores, etc. This counts a
4471 register twice if it is modified, but that is correct. */
4472 REG_N_SETS (i) += 1;
4473 REG_N_REFS (i) += (optimize_size ? 1
4474 : pbi->bb->loop_depth + 1);
4476 /* The insns where a reg is live are normally counted
4477 elsewhere, but we want the count to include the insn
4478 where the reg is set, and the normal counting mechanism
4479 would not count it. */
4480 REG_LIVE_LENGTH (i) += 1;
4483 /* If this is a hard reg, record this function uses the reg. */
4484 if (regno_first < FIRST_PSEUDO_REGISTER)
4486 for (i = regno_first; i <= regno_last; i++)
4487 regs_ever_live[i] = 1;
4491 /* Keep track of which basic blocks each reg appears in. */
4492 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
4493 REG_BASIC_BLOCK (regno_first) = blocknum;
4494 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
4495 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
4499 if (! some_was_dead)
4501 if (flags & PROP_LOG_LINKS)
4503 /* Make a logical link from the next following insn
4504 that uses this register, back to this insn.
4505 The following insns have already been processed.
4507 We don't build a LOG_LINK for hard registers containing
4508 in ASM_OPERANDs. If these registers get replaced,
4509 we might wind up changing the semantics of the insn,
4510 even if reload can make what appear to be valid
4511 assignments later. */
4512 if (y && (BLOCK_NUM (y) == blocknum)
4513 && (regno_first >= FIRST_PSEUDO_REGISTER
4514 || asm_noperands (PATTERN (y)) < 0))
4515 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
4520 else if (! some_was_live)
4522 if (flags & PROP_REG_INFO)
4523 REG_N_DEATHS (regno_first) += 1;
4525 if (flags & PROP_DEATH_NOTES)
4527 /* Note that dead stores have already been deleted
4528 when possible. If we get here, we have found a
4529 dead store that cannot be eliminated (because the
4530 same insn does something useful). Indicate this
4531 by marking the reg being set as dying here. */
4533 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
4538 if (flags & PROP_DEATH_NOTES)
4540 /* This is a case where we have a multi-word hard register
4541 and some, but not all, of the words of the register are
4542 needed in subsequent insns. Write REG_UNUSED notes
4543 for those parts that were not needed. This case should
4546 for (i = regno_first; i <= regno_last; ++i)
4547 if (! REGNO_REG_SET_P (pbi->reg_live, i))
4549 = alloc_EXPR_LIST (REG_UNUSED,
4550 gen_rtx_REG (reg_raw_mode[i], i),
4556 /* Mark the register as being dead. */
4559 /* The stack pointer is never dead. Well, not strictly true,
4560 but it's very difficult to tell from here. Hopefully
4561 combine_stack_adjustments will fix up the most egregious
4563 && regno_first != STACK_POINTER_REGNUM)
4565 for (i = regno_first; i <= regno_last; ++i)
4566 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
4569 else if (GET_CODE (reg) == REG)
4571 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4572 pbi->reg_next_use[regno_first] = 0;
4575 /* If this is the last pass and this is a SCRATCH, show it will be dying
4576 here and count it. */
4577 else if (GET_CODE (reg) == SCRATCH)
4579 if (flags & PROP_DEATH_NOTES)
4581 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
4585 #ifdef HAVE_conditional_execution
4586 /* Mark REGNO conditionally dead.
4587 Return true if the register is now unconditionally dead. */
4590 mark_regno_cond_dead (pbi, regno, cond)
4591 struct propagate_block_info *pbi;
4595 /* If this is a store to a predicate register, the value of the
4596 predicate is changing, we don't know that the predicate as seen
4597 before is the same as that seen after. Flush all dependent
4598 conditions from reg_cond_dead. This will make all such
4599 conditionally live registers unconditionally live. */
4600 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
4601 flush_reg_cond_reg (pbi, regno);
4603 /* If this is an unconditional store, remove any conditional
4604 life that may have existed. */
4605 if (cond == NULL_RTX)
4606 splay_tree_remove (pbi->reg_cond_dead, regno);
4609 splay_tree_node node;
4610 struct reg_cond_life_info *rcli;
4613 /* Otherwise this is a conditional set. Record that fact.
4614 It may have been conditionally used, or there may be a
4615 subsequent set with a complimentary condition. */
4617 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
4620 /* The register was unconditionally live previously.
4621 Record the current condition as the condition under
4622 which it is dead. */
4623 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
4624 rcli->condition = alloc_EXPR_LIST (0, cond, NULL_RTX);
4625 splay_tree_insert (pbi->reg_cond_dead, regno,
4626 (splay_tree_value) rcli);
4628 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
4630 /* Not unconditionaly dead. */
4635 /* The register was conditionally live previously.
4636 Add the new condition to the old. */
4637 rcli = (struct reg_cond_life_info *) node->value;
4638 ncond = rcli->condition;
4639 ncond = ior_reg_cond (ncond, cond);
4641 /* If the register is now unconditionally dead,
4642 remove the entry in the splay_tree. */
4643 if (ncond == const1_rtx)
4644 splay_tree_remove (pbi->reg_cond_dead, regno);
4647 rcli->condition = ncond;
4649 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
4651 /* Not unconditionaly dead. */
4660 /* Called from splay_tree_delete for pbi->reg_cond_life. */
4663 free_reg_cond_life_info (value)
4664 splay_tree_value value;
4666 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
4667 free_EXPR_LIST_list (&rcli->condition);
4671 /* Helper function for flush_reg_cond_reg. */
4674 flush_reg_cond_reg_1 (node, data)
4675 splay_tree_node node;
4678 struct reg_cond_life_info *rcli;
4679 int *xdata = (int *) data;
4680 unsigned int regno = xdata[0];
4683 /* Don't need to search if last flushed value was farther on in
4684 the in-order traversal. */
4685 if (xdata[1] >= (int) node->key)
4688 /* Splice out portions of the expression that refer to regno. */
4689 rcli = (struct reg_cond_life_info *) node->value;
4690 c = *(prev = &rcli->condition);
4693 if (regno == REGNO (XEXP (XEXP (c, 0), 0)))
4695 rtx next = XEXP (c, 1);
4696 free_EXPR_LIST_node (c);
4700 c = *(prev = &XEXP (c, 1));
4703 /* If the entire condition is now NULL, signal the node to be removed. */
4704 if (! rcli->condition)
4706 xdata[1] = node->key;
4713 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
4716 flush_reg_cond_reg (pbi, regno)
4717 struct propagate_block_info *pbi;
4724 while (splay_tree_foreach (pbi->reg_cond_dead,
4725 flush_reg_cond_reg_1, pair) == -1)
4726 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
4728 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
4731 /* Logical arithmetic on predicate conditions. IOR, NOT and NAND.
4732 We actually use EXPR_LIST to chain the sub-expressions together
4733 instead of IOR because it's easier to manipulate and we have
4734 the lists.c functions to reuse nodes.
4736 Return a new rtl expression as appropriate. */
4739 ior_reg_cond (old, x)
4742 enum rtx_code x_code;
4746 /* We expect these conditions to be of the form (eq reg 0). */
4747 x_code = GET_CODE (x);
4748 if (GET_RTX_CLASS (x_code) != '<'
4749 || GET_CODE (x_reg = XEXP (x, 0)) != REG
4750 || XEXP (x, 1) != const0_rtx)
4753 /* Search the expression for an existing sub-expression of X_REG. */
4754 for (c = old; c; c = XEXP (c, 1))
4756 rtx y = XEXP (c, 0);
4757 if (REGNO (XEXP (y, 0)) == REGNO (x_reg))
4759 /* If we find X already present in OLD, we need do nothing. */
4760 if (GET_CODE (y) == x_code)
4763 /* If we find X being a compliment of a condition in OLD,
4764 then the entire condition is true. */
4765 if (GET_CODE (y) == reverse_condition (x_code))
4770 /* Otherwise just add to the chain. */
4771 return alloc_EXPR_LIST (0, x, old);
4778 enum rtx_code x_code;
4781 /* We expect these conditions to be of the form (eq reg 0). */
4782 x_code = GET_CODE (x);
4783 if (GET_RTX_CLASS (x_code) != '<'
4784 || GET_CODE (x_reg = XEXP (x, 0)) != REG
4785 || XEXP (x, 1) != const0_rtx)
4788 return alloc_EXPR_LIST (0, gen_rtx_fmt_ee (reverse_condition (x_code),
4789 VOIDmode, x_reg, const0_rtx),
4794 nand_reg_cond (old, x)
4797 enum rtx_code x_code;
4801 /* We expect these conditions to be of the form (eq reg 0). */
4802 x_code = GET_CODE (x);
4803 if (GET_RTX_CLASS (x_code) != '<'
4804 || GET_CODE (x_reg = XEXP (x, 0)) != REG
4805 || XEXP (x, 1) != const0_rtx)
4808 /* Search the expression for an existing sub-expression of X_REG. */
4810 for (c = *(prev = &old); c; c = *(prev = &XEXP (c, 1)))
4812 rtx y = XEXP (c, 0);
4813 if (REGNO (XEXP (y, 0)) == REGNO (x_reg))
4815 /* If we find X already present in OLD, then we need to
4817 if (GET_CODE (y) == x_code)
4819 *prev = XEXP (c, 1);
4820 free_EXPR_LIST_node (c);
4821 return old ? old : const0_rtx;
4824 /* If we find X being a compliment of a condition in OLD,
4825 then we need do nothing. */
4826 if (GET_CODE (y) == reverse_condition (x_code))
4831 /* Otherwise, by implication, the register in question is now live for
4832 the inverse of the condition X. */
4833 return alloc_EXPR_LIST (0, gen_rtx_fmt_ee (reverse_condition (x_code),
4834 VOIDmode, x_reg, const0_rtx),
4837 #endif /* HAVE_conditional_execution */
4841 /* Try to substitute the auto-inc expression INC as the address inside
4842 MEM which occurs in INSN. Currently, the address of MEM is an expression
4843 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
4844 that has a single set whose source is a PLUS of INCR_REG and something
4848 attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
4849 struct propagate_block_info *pbi;
4850 rtx inc, insn, mem, incr, incr_reg;
4852 int regno = REGNO (incr_reg);
4853 rtx set = single_set (incr);
4854 rtx q = SET_DEST (set);
4855 rtx y = SET_SRC (set);
4856 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
4858 /* Make sure this reg appears only once in this insn. */
4859 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
4862 if (dead_or_set_p (incr, incr_reg)
4863 /* Mustn't autoinc an eliminable register. */
4864 && (regno >= FIRST_PSEUDO_REGISTER
4865 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
4867 /* This is the simple case. Try to make the auto-inc. If
4868 we can't, we are done. Otherwise, we will do any
4869 needed updates below. */
4870 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
4873 else if (GET_CODE (q) == REG
4874 /* PREV_INSN used here to check the semi-open interval
4876 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
4877 /* We must also check for sets of q as q may be
4878 a call clobbered hard register and there may
4879 be a call between PREV_INSN (insn) and incr. */
4880 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
4882 /* We have *p followed sometime later by q = p+size.
4883 Both p and q must be live afterward,
4884 and q is not used between INSN and its assignment.
4885 Change it to q = p, ...*q..., q = q+size.
4886 Then fall into the usual case. */
4890 emit_move_insn (q, incr_reg);
4891 insns = get_insns ();
4894 if (basic_block_for_insn)
4895 for (temp = insns; temp; temp = NEXT_INSN (temp))
4896 set_block_for_insn (temp, pbi->bb);
4898 /* If we can't make the auto-inc, or can't make the
4899 replacement into Y, exit. There's no point in making
4900 the change below if we can't do the auto-inc and doing
4901 so is not correct in the pre-inc case. */
4904 validate_change (insn, &XEXP (mem, 0), inc, 1);
4905 validate_change (incr, &XEXP (y, opnum), q, 1);
4906 if (! apply_change_group ())
4909 /* We now know we'll be doing this change, so emit the
4910 new insn(s) and do the updates. */
4911 emit_insns_before (insns, insn);
4913 if (pbi->bb->head == insn)
4914 pbi->bb->head = insns;
4916 /* INCR will become a NOTE and INSN won't contain a
4917 use of INCR_REG. If a use of INCR_REG was just placed in
4918 the insn before INSN, make that the next use.
4919 Otherwise, invalidate it. */
4920 if (GET_CODE (PREV_INSN (insn)) == INSN
4921 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
4922 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
4923 pbi->reg_next_use[regno] = PREV_INSN (insn);
4925 pbi->reg_next_use[regno] = 0;
4930 /* REGNO is now used in INCR which is below INSN, but
4931 it previously wasn't live here. If we don't mark
4932 it as live, we'll put a REG_DEAD note for it
4933 on this insn, which is incorrect. */
4934 SET_REGNO_REG_SET (pbi->reg_live, regno);
4936 /* If there are any calls between INSN and INCR, show
4937 that REGNO now crosses them. */
4938 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
4939 if (GET_CODE (temp) == CALL_INSN)
4940 REG_N_CALLS_CROSSED (regno)++;
4945 /* If we haven't returned, it means we were able to make the
4946 auto-inc, so update the status. First, record that this insn
4947 has an implicit side effect. */
4949 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
4951 /* Modify the old increment-insn to simply copy
4952 the already-incremented value of our register. */
4953 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
4956 /* If that makes it a no-op (copying the register into itself) delete
4957 it so it won't appear to be a "use" and a "set" of this
4959 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
4961 /* If the original source was dead, it's dead now. */
4964 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
4966 remove_note (incr, note);
4967 if (XEXP (note, 0) != incr_reg)
4968 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
4971 PUT_CODE (incr, NOTE);
4972 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
4973 NOTE_SOURCE_FILE (incr) = 0;
4976 if (regno >= FIRST_PSEUDO_REGISTER)
4978 /* Count an extra reference to the reg. When a reg is
4979 incremented, spilling it is worse, so we want to make
4980 that less likely. */
4981 REG_N_REFS (regno) += (optimize_size ? 1 : pbi->bb->loop_depth + 1);
4983 /* Count the increment as a setting of the register,
4984 even though it isn't a SET in rtl. */
4985 REG_N_SETS (regno)++;
4989 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
4993 find_auto_inc (pbi, x, insn)
4994 struct propagate_block_info *pbi;
4998 rtx addr = XEXP (x, 0);
4999 HOST_WIDE_INT offset = 0;
5000 rtx set, y, incr, inc_val;
5002 int size = GET_MODE_SIZE (GET_MODE (x));
5004 if (GET_CODE (insn) == JUMP_INSN)
5007 /* Here we detect use of an index register which might be good for
5008 postincrement, postdecrement, preincrement, or predecrement. */
5010 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
5011 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
5013 if (GET_CODE (addr) != REG)
5016 regno = REGNO (addr);
5018 /* Is the next use an increment that might make auto-increment? */
5019 incr = pbi->reg_next_use[regno];
5020 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
5022 set = single_set (incr);
5023 if (set == 0 || GET_CODE (set) != SET)
5027 if (GET_CODE (y) != PLUS)
5030 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
5031 inc_val = XEXP (y, 1);
5032 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
5033 inc_val = XEXP (y, 0);
5037 if (GET_CODE (inc_val) == CONST_INT)
5039 if (HAVE_POST_INCREMENT
5040 && (INTVAL (inc_val) == size && offset == 0))
5041 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
5043 else if (HAVE_POST_DECREMENT
5044 && (INTVAL (inc_val) == -size && offset == 0))
5045 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
5047 else if (HAVE_PRE_INCREMENT
5048 && (INTVAL (inc_val) == size && offset == size))
5049 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
5051 else if (HAVE_PRE_DECREMENT
5052 && (INTVAL (inc_val) == -size && offset == -size))
5053 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
5055 else if (HAVE_POST_MODIFY_DISP && offset == 0)
5056 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
5057 gen_rtx_PLUS (Pmode,
5060 insn, x, incr, addr);
5062 else if (GET_CODE (inc_val) == REG
5063 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
5067 if (HAVE_POST_MODIFY_REG && offset == 0)
5068 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
5069 gen_rtx_PLUS (Pmode,
5072 insn, x, incr, addr);
5076 #endif /* AUTO_INC_DEC */
5079 mark_used_reg (pbi, reg, cond, insn)
5080 struct propagate_block_info *pbi;
5082 rtx cond ATTRIBUTE_UNUSED;
5085 int regno = REGNO (reg);
5086 int some_was_live = REGNO_REG_SET_P (pbi->reg_live, regno);
5087 int some_was_dead = ! some_was_live;
5091 /* A hard reg in a wide mode may really be multiple registers.
5092 If so, mark all of them just like the first. */
5093 if (regno < FIRST_PSEUDO_REGISTER)
5095 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5098 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, regno + n);
5099 some_was_live |= needed_regno;
5100 some_was_dead |= ! needed_regno;
5104 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
5106 /* Record where each reg is used, so when the reg is set we know
5107 the next insn that uses it. */
5108 pbi->reg_next_use[regno] = insn;
5111 if (pbi->flags & PROP_REG_INFO)
5113 if (regno < FIRST_PSEUDO_REGISTER)
5115 /* If this is a register we are going to try to eliminate,
5116 don't mark it live here. If we are successful in
5117 eliminating it, it need not be live unless it is used for
5118 pseudos, in which case it will have been set live when it
5119 was allocated to the pseudos. If the register will not
5120 be eliminated, reload will set it live at that point.
5122 Otherwise, record that this function uses this register. */
5123 /* ??? The PPC backend tries to "eliminate" on the pic
5124 register to itself. This should be fixed. In the mean
5125 time, hack around it. */
5127 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno)
5128 && (regno == FRAME_POINTER_REGNUM
5129 || regno == ARG_POINTER_REGNUM)))
5131 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5133 regs_ever_live[regno + --n] = 1;
5139 /* Keep track of which basic block each reg appears in. */
5141 register int blocknum = pbi->bb->index;
5142 if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN)
5143 REG_BASIC_BLOCK (regno) = blocknum;
5144 else if (REG_BASIC_BLOCK (regno) != blocknum)
5145 REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL;
5147 /* Count (weighted) number of uses of each reg. */
5148 REG_N_REFS (regno) += (optimize_size ? 1
5149 : pbi->bb->loop_depth + 1);
5153 /* Find out if any of the register was set this insn. */
5154 some_not_set = ! REGNO_REG_SET_P (pbi->new_set, regno);
5155 if (regno < FIRST_PSEUDO_REGISTER)
5157 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5159 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, regno + n);
5162 /* Record and count the insns in which a reg dies. If it is used in
5163 this insn and was dead below the insn then it dies in this insn.
5164 If it was set in this insn, we do not make a REG_DEAD note;
5165 likewise if we already made such a note. */
5166 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
5170 /* Check for the case where the register dying partially
5171 overlaps the register set by this insn. */
5172 if (regno < FIRST_PSEUDO_REGISTER
5173 && HARD_REGNO_NREGS (regno, GET_MODE (reg)) > 1)
5175 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5177 some_was_live |= REGNO_REG_SET_P (pbi->new_set, regno + n);
5180 /* If none of the words in X is needed, make a REG_DEAD note.
5181 Otherwise, we must make partial REG_DEAD notes. */
5182 if (! some_was_live)
5184 if ((pbi->flags & PROP_DEATH_NOTES)
5185 && ! find_regno_note (insn, REG_DEAD, regno))
5187 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
5189 if (pbi->flags & PROP_REG_INFO)
5190 REG_N_DEATHS (regno)++;
5194 /* Don't make a REG_DEAD note for a part of a register
5195 that is set in the insn. */
5197 n = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)) - 1;
5198 for (; n >= regno; n--)
5199 if (! REGNO_REG_SET_P (pbi->reg_live, n)
5200 && ! dead_or_set_regno_p (insn, n))
5202 = alloc_EXPR_LIST (REG_DEAD,
5203 gen_rtx_REG (reg_raw_mode[n], n),
5208 SET_REGNO_REG_SET (pbi->reg_live, regno);
5209 if (regno < FIRST_PSEUDO_REGISTER)
5211 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5213 SET_REGNO_REG_SET (pbi->reg_live, regno + n);
5216 #ifdef HAVE_conditional_execution
5217 /* If this is a conditional use, record that fact. If it is later
5218 conditionally set, we'll know to kill the register. */
5219 if (cond != NULL_RTX)
5221 splay_tree_node node;
5222 struct reg_cond_life_info *rcli;
5227 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
5230 /* The register was unconditionally live previously.
5231 No need to do anything. */
5235 /* The register was conditionally live previously.
5236 Subtract the new life cond from the old death cond. */
5237 rcli = (struct reg_cond_life_info *) node->value;
5238 ncond = rcli->condition;
5239 ncond = nand_reg_cond (ncond, cond);
5241 /* If the register is now unconditionally live, remove the
5242 entry in the splay_tree. */
5243 if (ncond == const0_rtx)
5245 rcli->condition = NULL_RTX;
5246 splay_tree_remove (pbi->reg_cond_dead, regno);
5250 rcli->condition = ncond;
5251 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5257 /* The register was not previously live at all. Record
5258 the condition under which it is still dead. */
5259 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
5260 rcli->condition = not_reg_cond (cond);
5261 splay_tree_insert (pbi->reg_cond_dead, regno,
5262 (splay_tree_value) rcli);
5264 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
5267 else if (some_was_live)
5269 splay_tree_node node;
5270 struct reg_cond_life_info *rcli;
5272 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
5275 /* The register was conditionally live previously, but is now
5276 unconditionally so. Remove it from the conditionally dead
5277 list, so that a conditional set won't cause us to think
5279 rcli = (struct reg_cond_life_info *) node->value;
5280 rcli->condition = NULL_RTX;
5281 splay_tree_remove (pbi->reg_cond_dead, regno);
5288 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
5289 This is done assuming the registers needed from X are those that
5290 have 1-bits in PBI->REG_LIVE.
5292 INSN is the containing instruction. If INSN is dead, this function
5296 mark_used_regs (pbi, x, cond, insn)
5297 struct propagate_block_info *pbi;
5300 register RTX_CODE code;
5302 int flags = pbi->flags;
5305 code = GET_CODE (x);
5325 /* If we are clobbering a MEM, mark any registers inside the address
5327 if (GET_CODE (XEXP (x, 0)) == MEM)
5328 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
5332 /* Don't bother watching stores to mems if this is not the
5333 final pass. We'll not be deleting dead stores this round. */
5334 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
5336 /* Invalidate the data for the last MEM stored, but only if MEM is
5337 something that can be stored into. */
5338 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
5339 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
5340 /* Needn't clear the memory set list. */
5344 rtx temp = pbi->mem_set_list;
5345 rtx prev = NULL_RTX;
5350 next = XEXP (temp, 1);
5351 if (anti_dependence (XEXP (temp, 0), x))
5353 /* Splice temp out of the list. */
5355 XEXP (prev, 1) = next;
5357 pbi->mem_set_list = next;
5358 free_EXPR_LIST_node (temp);
5366 /* If the memory reference had embedded side effects (autoincrement
5367 address modes. Then we may need to kill some entries on the
5370 invalidate_mems_from_autoinc (pbi, insn);
5374 if (flags & PROP_AUTOINC)
5375 find_auto_inc (pbi, x, insn);
5380 #ifdef CLASS_CANNOT_CHANGE_MODE
5381 if (GET_CODE (SUBREG_REG (x)) == REG
5382 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
5383 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
5384 GET_MODE (SUBREG_REG (x))))
5385 REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
5388 /* While we're here, optimize this case. */
5390 if (GET_CODE (x) != REG)
5395 /* See a register other than being set => mark it as needed. */
5396 mark_used_reg (pbi, x, cond, insn);
5401 register rtx testreg = SET_DEST (x);
5404 /* If storing into MEM, don't show it as being used. But do
5405 show the address as being used. */
5406 if (GET_CODE (testreg) == MEM)
5409 if (flags & PROP_AUTOINC)
5410 find_auto_inc (pbi, testreg, insn);
5412 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
5413 mark_used_regs (pbi, SET_SRC (x), cond, insn);
5417 /* Storing in STRICT_LOW_PART is like storing in a reg
5418 in that this SET might be dead, so ignore it in TESTREG.
5419 but in some other ways it is like using the reg.
5421 Storing in a SUBREG or a bit field is like storing the entire
5422 register in that if the register's value is not used
5423 then this SET is not needed. */
5424 while (GET_CODE (testreg) == STRICT_LOW_PART
5425 || GET_CODE (testreg) == ZERO_EXTRACT
5426 || GET_CODE (testreg) == SIGN_EXTRACT
5427 || GET_CODE (testreg) == SUBREG)
5429 #ifdef CLASS_CANNOT_CHANGE_MODE
5430 if (GET_CODE (testreg) == SUBREG
5431 && GET_CODE (SUBREG_REG (testreg)) == REG
5432 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
5433 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
5434 GET_MODE (testreg)))
5435 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
5438 /* Modifying a single register in an alternate mode
5439 does not use any of the old value. But these other
5440 ways of storing in a register do use the old value. */
5441 if (GET_CODE (testreg) == SUBREG
5442 && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
5447 testreg = XEXP (testreg, 0);
5450 /* If this is a store into a register, recursively scan the
5451 value being stored. */
5453 if ((GET_CODE (testreg) == PARALLEL
5454 && GET_MODE (testreg) == BLKmode)
5455 || (GET_CODE (testreg) == REG
5456 && (regno = REGNO (testreg),
5457 ! (regno == FRAME_POINTER_REGNUM
5458 && (! reload_completed || frame_pointer_needed)))
5459 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
5460 && ! (regno == HARD_FRAME_POINTER_REGNUM
5461 && (! reload_completed || frame_pointer_needed))
5463 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
5464 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
5469 mark_used_regs (pbi, SET_DEST (x), cond, insn);
5470 mark_used_regs (pbi, SET_SRC (x), cond, insn);
5477 case UNSPEC_VOLATILE:
5481 /* Traditional and volatile asm instructions must be considered to use
5482 and clobber all hard registers, all pseudo-registers and all of
5483 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
5485 Consider for instance a volatile asm that changes the fpu rounding
5486 mode. An insn should not be moved across this even if it only uses
5487 pseudo-regs because it might give an incorrectly rounded result.
5489 ?!? Unfortunately, marking all hard registers as live causes massive
5490 problems for the register allocator and marking all pseudos as live
5491 creates mountains of uninitialized variable warnings.
5493 So for now, just clear the memory set list and mark any regs
5494 we can find in ASM_OPERANDS as used. */
5495 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
5496 free_EXPR_LIST_list (&pbi->mem_set_list);
5498 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
5499 We can not just fall through here since then we would be confused
5500 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
5501 traditional asms unlike their normal usage. */
5502 if (code == ASM_OPERANDS)
5506 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
5507 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
5513 if (cond != NULL_RTX)
5516 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
5518 cond = COND_EXEC_TEST (x);
5519 x = COND_EXEC_CODE (x);
5523 /* We _do_not_ want to scan operands of phi nodes. Operands of
5524 a phi function are evaluated only when control reaches this
5525 block along a particular edge. Therefore, regs that appear
5526 as arguments to phi should not be added to the global live at
5534 /* Recursively scan the operands of this expression. */
5537 register const char *fmt = GET_RTX_FORMAT (code);
5540 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5544 /* Tail recursive case: save a function call level. */
5550 mark_used_regs (pbi, XEXP (x, i), cond, insn);
5552 else if (fmt[i] == 'E')
5555 for (j = 0; j < XVECLEN (x, i); j++)
5556 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
5565 try_pre_increment_1 (pbi, insn)
5566 struct propagate_block_info *pbi;
5569 /* Find the next use of this reg. If in same basic block,
5570 make it do pre-increment or pre-decrement if appropriate. */
5571 rtx x = single_set (insn);
5572 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
5573 * INTVAL (XEXP (SET_SRC (x), 1)));
5574 int regno = REGNO (SET_DEST (x));
5575 rtx y = pbi->reg_next_use[regno];
5577 && BLOCK_NUM (y) == BLOCK_NUM (insn)
5578 /* Don't do this if the reg dies, or gets set in y; a standard addressing
5579 mode would be better. */
5580 && ! dead_or_set_p (y, SET_DEST (x))
5581 && try_pre_increment (y, SET_DEST (x), amount))
5583 /* We have found a suitable auto-increment
5584 and already changed insn Y to do it.
5585 So flush this increment-instruction. */
5586 PUT_CODE (insn, NOTE);
5587 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
5588 NOTE_SOURCE_FILE (insn) = 0;
5589 /* Count a reference to this reg for the increment
5590 insn we are deleting. When a reg is incremented.
5591 spilling it is worse, so we want to make that
5593 if (regno >= FIRST_PSEUDO_REGISTER)
5595 REG_N_REFS (regno) += (optimize_size ? 1
5596 : pbi->bb->loop_depth + 1);
5597 REG_N_SETS (regno)++;
5604 /* Try to change INSN so that it does pre-increment or pre-decrement
5605 addressing on register REG in order to add AMOUNT to REG.
5606 AMOUNT is negative for pre-decrement.
5607 Returns 1 if the change could be made.
5608 This checks all about the validity of the result of modifying INSN. */
5611 try_pre_increment (insn, reg, amount)
5613 HOST_WIDE_INT amount;
5617 /* Nonzero if we can try to make a pre-increment or pre-decrement.
5618 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
5620 /* Nonzero if we can try to make a post-increment or post-decrement.
5621 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
5622 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
5623 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
5626 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
5629 /* From the sign of increment, see which possibilities are conceivable
5630 on this target machine. */
5631 if (HAVE_PRE_INCREMENT && amount > 0)
5633 if (HAVE_POST_INCREMENT && amount > 0)
5636 if (HAVE_PRE_DECREMENT && amount < 0)
5638 if (HAVE_POST_DECREMENT && amount < 0)
5641 if (! (pre_ok || post_ok))
5644 /* It is not safe to add a side effect to a jump insn
5645 because if the incremented register is spilled and must be reloaded
5646 there would be no way to store the incremented value back in memory. */
5648 if (GET_CODE (insn) == JUMP_INSN)
5653 use = find_use_as_address (PATTERN (insn), reg, 0);
5654 if (post_ok && (use == 0 || use == (rtx) 1))
5656 use = find_use_as_address (PATTERN (insn), reg, -amount);
5660 if (use == 0 || use == (rtx) 1)
5663 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
5666 /* See if this combination of instruction and addressing mode exists. */
5667 if (! validate_change (insn, &XEXP (use, 0),
5668 gen_rtx_fmt_e (amount > 0
5669 ? (do_post ? POST_INC : PRE_INC)
5670 : (do_post ? POST_DEC : PRE_DEC),
5674 /* Record that this insn now has an implicit side effect on X. */
5675 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
5679 #endif /* AUTO_INC_DEC */
5681 /* Find the place in the rtx X where REG is used as a memory address.
5682 Return the MEM rtx that so uses it.
5683 If PLUSCONST is nonzero, search instead for a memory address equivalent to
5684 (plus REG (const_int PLUSCONST)).
5686 If such an address does not appear, return 0.
5687 If REG appears more than once, or is used other than in such an address,
5691 find_use_as_address (x, reg, plusconst)
5694 HOST_WIDE_INT plusconst;
5696 enum rtx_code code = GET_CODE (x);
5697 const char *fmt = GET_RTX_FORMAT (code);
5699 register rtx value = 0;
5702 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
5705 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
5706 && XEXP (XEXP (x, 0), 0) == reg
5707 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
5708 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
5711 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
5713 /* If REG occurs inside a MEM used in a bit-field reference,
5714 that is unacceptable. */
5715 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
5716 return (rtx) (HOST_WIDE_INT) 1;
5720 return (rtx) (HOST_WIDE_INT) 1;
5722 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5726 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
5730 return (rtx) (HOST_WIDE_INT) 1;
5732 else if (fmt[i] == 'E')
5735 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
5737 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
5741 return (rtx) (HOST_WIDE_INT) 1;
5749 /* Write information about registers and basic blocks into FILE.
5750 This is part of making a debugging dump. */
5753 dump_regset (r, outf)
5760 fputs (" (nil)", outf);
5764 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
5766 fprintf (outf, " %d", i);
5767 if (i < FIRST_PSEUDO_REGISTER)
5768 fprintf (outf, " [%s]",
5777 dump_regset (r, stderr);
5778 putc ('\n', stderr);
5782 dump_flow_info (file)
5786 static const char * const reg_class_names[] = REG_CLASS_NAMES;
5788 fprintf (file, "%d registers.\n", max_regno);
5789 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
5792 enum reg_class class, altclass;
5793 fprintf (file, "\nRegister %d used %d times across %d insns",
5794 i, REG_N_REFS (i), REG_LIVE_LENGTH (i));
5795 if (REG_BASIC_BLOCK (i) >= 0)
5796 fprintf (file, " in block %d", REG_BASIC_BLOCK (i));
5798 fprintf (file, "; set %d time%s", REG_N_SETS (i),
5799 (REG_N_SETS (i) == 1) ? "" : "s");
5800 if (REG_USERVAR_P (regno_reg_rtx[i]))
5801 fprintf (file, "; user var");
5802 if (REG_N_DEATHS (i) != 1)
5803 fprintf (file, "; dies in %d places", REG_N_DEATHS (i));
5804 if (REG_N_CALLS_CROSSED (i) == 1)
5805 fprintf (file, "; crosses 1 call");
5806 else if (REG_N_CALLS_CROSSED (i))
5807 fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i));
5808 if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
5809 fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
5810 class = reg_preferred_class (i);
5811 altclass = reg_alternate_class (i);
5812 if (class != GENERAL_REGS || altclass != ALL_REGS)
5814 if (altclass == ALL_REGS || class == ALL_REGS)
5815 fprintf (file, "; pref %s", reg_class_names[(int) class]);
5816 else if (altclass == NO_REGS)
5817 fprintf (file, "; %s or none", reg_class_names[(int) class]);
5819 fprintf (file, "; pref %s, else %s",
5820 reg_class_names[(int) class],
5821 reg_class_names[(int) altclass]);
5823 if (REGNO_POINTER_FLAG (i))
5824 fprintf (file, "; pointer");
5825 fprintf (file, ".\n");
5828 fprintf (file, "\n%d basic blocks, %d edges.\n", n_basic_blocks, n_edges);
5829 for (i = 0; i < n_basic_blocks; i++)
5831 register basic_block bb = BASIC_BLOCK (i);
5834 fprintf (file, "\nBasic block %d: first insn %d, last %d, loop_depth %d, count %d.\n",
5835 i, INSN_UID (bb->head), INSN_UID (bb->end), bb->loop_depth, bb->count);
5837 fprintf (file, "Predecessors: ");
5838 for (e = bb->pred; e; e = e->pred_next)
5839 dump_edge_info (file, e, 0);
5841 fprintf (file, "\nSuccessors: ");
5842 for (e = bb->succ; e; e = e->succ_next)
5843 dump_edge_info (file, e, 1);
5845 fprintf (file, "\nRegisters live at start:");
5846 dump_regset (bb->global_live_at_start, file);
5848 fprintf (file, "\nRegisters live at end:");
5849 dump_regset (bb->global_live_at_end, file);
5860 dump_flow_info (stderr);
5864 dump_edge_info (file, e, do_succ)
5869 basic_block side = (do_succ ? e->dest : e->src);
5871 if (side == ENTRY_BLOCK_PTR)
5872 fputs (" ENTRY", file);
5873 else if (side == EXIT_BLOCK_PTR)
5874 fputs (" EXIT", file);
5876 fprintf (file, " %d", side->index);
5879 fprintf (file, " count:%d", e->count);
5883 static const char * const bitnames[] = {
5884 "fallthru", "crit", "ab", "abcall", "eh", "fake"
5887 int i, flags = e->flags;
5891 for (i = 0; flags; i++)
5892 if (flags & (1 << i))
5898 if (i < (int) (sizeof (bitnames) / sizeof (*bitnames)))
5899 fputs (bitnames[i], file);
5901 fprintf (file, "%d", i);
5908 /* Print out one basic block with live information at start and end. */
5919 fprintf (outf, ";; Basic block %d, loop depth %d, count %d",
5920 bb->index, bb->loop_depth, bb->count);
5921 if (bb->eh_beg != -1 || bb->eh_end != -1)
5922 fprintf (outf, ", eh regions %d/%d", bb->eh_beg, bb->eh_end);
5925 fputs (";; Predecessors: ", outf);
5926 for (e = bb->pred; e; e = e->pred_next)
5927 dump_edge_info (outf, e, 0);
5930 fputs (";; Registers live at start:", outf);
5931 dump_regset (bb->global_live_at_start, outf);
5934 for (insn = bb->head, last = NEXT_INSN (bb->end);
5936 insn = NEXT_INSN (insn))
5937 print_rtl_single (outf, insn);
5939 fputs (";; Registers live at end:", outf);
5940 dump_regset (bb->global_live_at_end, outf);
5943 fputs (";; Successors: ", outf);
5944 for (e = bb->succ; e; e = e->succ_next)
5945 dump_edge_info (outf, e, 1);
5953 dump_bb (bb, stderr);
5960 dump_bb (BASIC_BLOCK (n), stderr);
5963 /* Like print_rtl, but also print out live information for the start of each
5967 print_rtl_with_bb (outf, rtx_first)
5971 register rtx tmp_rtx;
5974 fprintf (outf, "(nil)\n");
5978 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
5979 int max_uid = get_max_uid ();
5980 basic_block *start = (basic_block *)
5981 xcalloc (max_uid, sizeof (basic_block));
5982 basic_block *end = (basic_block *)
5983 xcalloc (max_uid, sizeof (basic_block));
5984 enum bb_state *in_bb_p = (enum bb_state *)
5985 xcalloc (max_uid, sizeof (enum bb_state));
5987 for (i = n_basic_blocks - 1; i >= 0; i--)
5989 basic_block bb = BASIC_BLOCK (i);
5992 start[INSN_UID (bb->head)] = bb;
5993 end[INSN_UID (bb->end)] = bb;
5994 for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x))
5996 enum bb_state state = IN_MULTIPLE_BB;
5997 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
5999 in_bb_p[INSN_UID (x)] = state;
6006 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
6011 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
6013 fprintf (outf, ";; Start of basic block %d, registers live:",
6015 dump_regset (bb->global_live_at_start, outf);
6019 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
6020 && GET_CODE (tmp_rtx) != NOTE
6021 && GET_CODE (tmp_rtx) != BARRIER)
6022 fprintf (outf, ";; Insn is not within a basic block\n");
6023 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
6024 fprintf (outf, ";; Insn is in multiple basic blocks\n");
6026 did_output = print_rtl_single (outf, tmp_rtx);
6028 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
6030 fprintf (outf, ";; End of basic block %d, registers live:\n",
6032 dump_regset (bb->global_live_at_end, outf);
6045 if (current_function_epilogue_delay_list != 0)
6047 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
6048 for (tmp_rtx = current_function_epilogue_delay_list; tmp_rtx != 0;
6049 tmp_rtx = XEXP (tmp_rtx, 1))
6050 print_rtl_single (outf, XEXP (tmp_rtx, 0));
6054 /* Compute dominator relationships using new flow graph structures. */
6057 compute_flow_dominators (dominators, post_dominators)
6058 sbitmap *dominators;
6059 sbitmap *post_dominators;
6062 sbitmap *temp_bitmap;
6064 basic_block *worklist, *workend, *qin, *qout;
6067 /* Allocate a worklist array/queue. Entries are only added to the
6068 list if they were not already on the list. So the size is
6069 bounded by the number of basic blocks. */
6070 worklist = (basic_block *) xmalloc (sizeof (basic_block) * n_basic_blocks);
6071 workend = &worklist[n_basic_blocks];
6073 temp_bitmap = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
6074 sbitmap_vector_zero (temp_bitmap, n_basic_blocks);
6078 /* The optimistic setting of dominators requires us to put every
6079 block on the work list initially. */
6080 qin = qout = worklist;
6081 for (bb = 0; bb < n_basic_blocks; bb++)
6083 *qin++ = BASIC_BLOCK (bb);
6084 BASIC_BLOCK (bb)->aux = BASIC_BLOCK (bb);
6086 qlen = n_basic_blocks;
6089 /* We want a maximal solution, so initially assume everything dominates
6091 sbitmap_vector_ones (dominators, n_basic_blocks);
6093 /* Mark successors of the entry block so we can identify them below. */
6094 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
6095 e->dest->aux = ENTRY_BLOCK_PTR;
6097 /* Iterate until the worklist is empty. */
6100 /* Take the first entry off the worklist. */
6101 basic_block b = *qout++;
6102 if (qout >= workend)
6108 /* Compute the intersection of the dominators of all the
6111 If one of the predecessor blocks is the ENTRY block, then the
6112 intersection of the dominators of the predecessor blocks is
6113 defined as the null set. We can identify such blocks by the
6114 special value in the AUX field in the block structure. */
6115 if (b->aux == ENTRY_BLOCK_PTR)
6117 /* Do not clear the aux field for blocks which are
6118 successors of the ENTRY block. That way we never add
6119 them to the worklist again.
6121 The intersect of dominators of the preds of this block is
6122 defined as the null set. */
6123 sbitmap_zero (temp_bitmap[bb]);
6127 /* Clear the aux field of this block so it can be added to
6128 the worklist again if necessary. */
6130 sbitmap_intersection_of_preds (temp_bitmap[bb], dominators, bb);
6133 /* Make sure each block always dominates itself. */
6134 SET_BIT (temp_bitmap[bb], bb);
6136 /* If the out state of this block changed, then we need to
6137 add the successors of this block to the worklist if they
6138 are not already on the worklist. */
6139 if (sbitmap_a_and_b (dominators[bb], dominators[bb], temp_bitmap[bb]))
6141 for (e = b->succ; e; e = e->succ_next)
6143 if (!e->dest->aux && e->dest != EXIT_BLOCK_PTR)
6157 if (post_dominators)
6159 /* The optimistic setting of dominators requires us to put every
6160 block on the work list initially. */
6161 qin = qout = worklist;
6162 for (bb = 0; bb < n_basic_blocks; bb++)
6164 *qin++ = BASIC_BLOCK (bb);
6165 BASIC_BLOCK (bb)->aux = BASIC_BLOCK (bb);
6167 qlen = n_basic_blocks;
6170 /* We want a maximal solution, so initially assume everything post
6171 dominates everything else. */
6172 sbitmap_vector_ones (post_dominators, n_basic_blocks);
6174 /* Mark predecessors of the exit block so we can identify them below. */
6175 for (e = EXIT_BLOCK_PTR->pred; e; e = e->pred_next)
6176 e->src->aux = EXIT_BLOCK_PTR;
6178 /* Iterate until the worklist is empty. */
6181 /* Take the first entry off the worklist. */
6182 basic_block b = *qout++;
6183 if (qout >= workend)
6189 /* Compute the intersection of the post dominators of all the
6192 If one of the successor blocks is the EXIT block, then the
6193 intersection of the dominators of the successor blocks is
6194 defined as the null set. We can identify such blocks by the
6195 special value in the AUX field in the block structure. */
6196 if (b->aux == EXIT_BLOCK_PTR)
6198 /* Do not clear the aux field for blocks which are
6199 predecessors of the EXIT block. That way we we never
6200 add them to the worklist again.
6202 The intersect of dominators of the succs of this block is
6203 defined as the null set. */
6204 sbitmap_zero (temp_bitmap[bb]);
6208 /* Clear the aux field of this block so it can be added to
6209 the worklist again if necessary. */
6211 sbitmap_intersection_of_succs (temp_bitmap[bb],
6212 post_dominators, bb);
6215 /* Make sure each block always post dominates itself. */
6216 SET_BIT (temp_bitmap[bb], bb);
6218 /* If the out state of this block changed, then we need to
6219 add the successors of this block to the worklist if they
6220 are not already on the worklist. */
6221 if (sbitmap_a_and_b (post_dominators[bb],
6222 post_dominators[bb],
6225 for (e = b->pred; e; e = e->pred_next)
6227 if (!e->src->aux && e->src != ENTRY_BLOCK_PTR)
6245 /* Given DOMINATORS, compute the immediate dominators into IDOM. If a
6246 block dominates only itself, its entry remains as INVALID_BLOCK. */
6249 compute_immediate_dominators (idom, dominators)
6251 sbitmap *dominators;
6256 tmp = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
6258 /* Begin with tmp(n) = dom(n) - { n }. */
6259 for (b = n_basic_blocks; --b >= 0;)
6261 sbitmap_copy (tmp[b], dominators[b]);
6262 RESET_BIT (tmp[b], b);
6265 /* Subtract out all of our dominator's dominators. */
6266 for (b = n_basic_blocks; --b >= 0;)
6268 sbitmap tmp_b = tmp[b];
6271 for (s = n_basic_blocks; --s >= 0;)
6272 if (TEST_BIT (tmp_b, s))
6273 sbitmap_difference (tmp_b, tmp_b, tmp[s]);
6276 /* Find the one bit set in the bitmap and put it in the output array. */
6277 for (b = n_basic_blocks; --b >= 0;)
6280 EXECUTE_IF_SET_IN_SBITMAP (tmp[b], 0, t, { idom[b] = t; });
6283 sbitmap_vector_free (tmp);
6286 /* Given POSTDOMINATORS, compute the immediate postdominators into
6287 IDOM. If a block is only dominated by itself, its entry remains as
6291 compute_immediate_postdominators (idom, postdominators)
6293 sbitmap *postdominators;
6295 compute_immediate_dominators (idom, postdominators);
6298 /* Recompute register set/reference counts immediately prior to register
6301 This avoids problems with set/reference counts changing to/from values
6302 which have special meanings to the register allocators.
6304 Additionally, the reference counts are the primary component used by the
6305 register allocators to prioritize pseudos for allocation to hard regs.
6306 More accurate reference counts generally lead to better register allocation.
6308 F is the first insn to be scanned.
6310 LOOP_STEP denotes how much loop_depth should be incremented per
6311 loop nesting level in order to increase the ref count more for
6312 references in a loop.
6314 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
6315 possibly other information which is used by the register allocators. */
6318 recompute_reg_usage (f, loop_step)
6319 rtx f ATTRIBUTE_UNUSED;
6320 int loop_step ATTRIBUTE_UNUSED;
6322 allocate_reg_life_data ();
6323 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
6326 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
6327 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
6328 of the number of registers that died. */
6331 count_or_remove_death_notes (blocks, kill)
6337 for (i = n_basic_blocks - 1; i >= 0; --i)
6342 if (blocks && ! TEST_BIT (blocks, i))
6345 bb = BASIC_BLOCK (i);
6347 for (insn = bb->head;; insn = NEXT_INSN (insn))
6351 rtx *pprev = ®_NOTES (insn);
6356 switch (REG_NOTE_KIND (link))
6359 if (GET_CODE (XEXP (link, 0)) == REG)
6361 rtx reg = XEXP (link, 0);
6364 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
6367 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
6375 rtx next = XEXP (link, 1);
6376 free_EXPR_LIST_node (link);
6377 *pprev = link = next;
6383 pprev = &XEXP (link, 1);
6390 if (insn == bb->end)
6398 /* Record INSN's block as BB. */
6401 set_block_for_insn (insn, bb)
6405 size_t uid = INSN_UID (insn);
6406 if (uid >= basic_block_for_insn->num_elements)
6410 /* Add one-eighth the size so we don't keep calling xrealloc. */
6411 new_size = uid + (uid + 7) / 8;
6413 VARRAY_GROW (basic_block_for_insn, new_size);
6415 VARRAY_BB (basic_block_for_insn, uid) = bb;
6418 /* Record INSN's block number as BB. */
6419 /* ??? This has got to go. */
6422 set_block_num (insn, bb)
6426 set_block_for_insn (insn, BASIC_BLOCK (bb));
6429 /* Verify the CFG consistency. This function check some CFG invariants and
6430 aborts when something is wrong. Hope that this function will help to
6431 convert many optimization passes to preserve CFG consistent.
6433 Currently it does following checks:
6435 - test head/end pointers
6436 - overlapping of basic blocks
6437 - edge list corectness
6438 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
6439 - tails of basic blocks (ensure that boundary is necesary)
6440 - scans body of the basic block for JUMP_INSN, CODE_LABEL
6441 and NOTE_INSN_BASIC_BLOCK
6442 - check that all insns are in the basic blocks
6443 (except the switch handling code, barriers and notes)
6444 - check that all returns are followed by barriers
6446 In future it can be extended check a lot of other stuff as well
6447 (reachability of basic blocks, life information, etc. etc.). */
6452 const int max_uid = get_max_uid ();
6453 const rtx rtx_first = get_insns ();
6454 rtx last_head = get_last_insn ();
6455 basic_block *bb_info;
6457 int i, last_bb_num_seen, num_bb_notes, err = 0;
6459 bb_info = (basic_block *) xcalloc (max_uid, sizeof (basic_block));
6461 for (i = n_basic_blocks - 1; i >= 0; i--)
6463 basic_block bb = BASIC_BLOCK (i);
6464 rtx head = bb->head;
6467 /* Verify the end of the basic block is in the INSN chain. */
6468 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
6473 error ("End insn %d for block %d not found in the insn stream.",
6474 INSN_UID (end), bb->index);
6478 /* Work backwards from the end to the head of the basic block
6479 to verify the head is in the RTL chain. */
6480 for (; x != NULL_RTX; x = PREV_INSN (x))
6482 /* While walking over the insn chain, verify insns appear
6483 in only one basic block and initialize the BB_INFO array
6484 used by other passes. */
6485 if (bb_info[INSN_UID (x)] != NULL)
6487 error ("Insn %d is in multiple basic blocks (%d and %d)",
6488 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
6491 bb_info[INSN_UID (x)] = bb;
6498 error ("Head insn %d for block %d not found in the insn stream.",
6499 INSN_UID (head), bb->index);
6506 /* Now check the basic blocks (boundaries etc.) */
6507 for (i = n_basic_blocks - 1; i >= 0; i--)
6509 basic_block bb = BASIC_BLOCK (i);
6510 /* Check corectness of edge lists */
6519 "verify_flow_info: Basic block %d succ edge is corrupted\n",
6521 fprintf (stderr, "Predecessor: ");
6522 dump_edge_info (stderr, e, 0);
6523 fprintf (stderr, "\nSuccessor: ");
6524 dump_edge_info (stderr, e, 1);
6528 if (e->dest != EXIT_BLOCK_PTR)
6530 edge e2 = e->dest->pred;
6531 while (e2 && e2 != e)
6535 error ("Basic block %i edge lists are corrupted", bb->index);
6547 error ("Basic block %d pred edge is corrupted", bb->index);
6548 fputs ("Predecessor: ", stderr);
6549 dump_edge_info (stderr, e, 0);
6550 fputs ("\nSuccessor: ", stderr);
6551 dump_edge_info (stderr, e, 1);
6552 fputc ('\n', stderr);
6555 if (e->src != ENTRY_BLOCK_PTR)
6557 edge e2 = e->src->succ;
6558 while (e2 && e2 != e)
6562 error ("Basic block %i edge lists are corrupted", bb->index);
6569 /* OK pointers are correct. Now check the header of basic
6570 block. It ought to contain optional CODE_LABEL followed
6571 by NOTE_BASIC_BLOCK. */
6573 if (GET_CODE (x) == CODE_LABEL)
6577 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
6583 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
6585 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d\n",
6592 /* Do checks for empty blocks here */
6599 if (NOTE_INSN_BASIC_BLOCK_P (x))
6601 error ("NOTE_INSN_BASIC_BLOCK %d in the middle of basic block %d",
6602 INSN_UID (x), bb->index);
6609 if (GET_CODE (x) == JUMP_INSN
6610 || GET_CODE (x) == CODE_LABEL
6611 || GET_CODE (x) == BARRIER)
6613 error ("In basic block %d:", bb->index);
6614 fatal_insn ("Flow control insn inside a basic block", x);
6622 last_bb_num_seen = -1;
6627 if (NOTE_INSN_BASIC_BLOCK_P (x))
6629 basic_block bb = NOTE_BASIC_BLOCK (x);
6631 if (bb->index != last_bb_num_seen + 1)
6632 fatal ("Basic blocks not numbered consecutively");
6633 last_bb_num_seen = bb->index;
6636 if (!bb_info[INSN_UID (x)])
6638 switch (GET_CODE (x))
6645 /* An addr_vec is placed outside any block block. */
6647 && GET_CODE (NEXT_INSN (x)) == JUMP_INSN
6648 && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
6649 || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
6654 /* But in any case, non-deletable labels can appear anywhere. */
6658 fatal_insn ("Insn outside basic block", x);
6663 && GET_CODE (x) == JUMP_INSN
6664 && returnjump_p (x) && ! condjump_p (x)
6665 && ! (NEXT_INSN (x) && GET_CODE (NEXT_INSN (x)) == BARRIER))
6666 fatal_insn ("Return not followed by barrier", x);
6671 if (num_bb_notes != n_basic_blocks)
6672 fatal ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
6673 num_bb_notes, n_basic_blocks);
6682 /* Functions to access an edge list with a vector representation.
6683 Enough data is kept such that given an index number, the
6684 pred and succ that edge represents can be determined, or
6685 given a pred and a succ, its index number can be returned.
6686 This allows algorithms which consume a lot of memory to
6687 represent the normally full matrix of edge (pred,succ) with a
6688 single indexed vector, edge (EDGE_INDEX (pred, succ)), with no
6689 wasted space in the client code due to sparse flow graphs. */
6691 /* This functions initializes the edge list. Basically the entire
6692 flowgraph is processed, and all edges are assigned a number,
6693 and the data structure is filled in. */
6698 struct edge_list *elist;
6704 block_count = n_basic_blocks + 2; /* Include the entry and exit blocks. */
6708 /* Determine the number of edges in the flow graph by counting successor
6709 edges on each basic block. */
6710 for (x = 0; x < n_basic_blocks; x++)
6712 basic_block bb = BASIC_BLOCK (x);
6714 for (e = bb->succ; e; e = e->succ_next)
6717 /* Don't forget successors of the entry block. */
6718 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
6721 elist = (struct edge_list *) xmalloc (sizeof (struct edge_list));
6722 elist->num_blocks = block_count;
6723 elist->num_edges = num_edges;
6724 elist->index_to_edge = (edge *) xmalloc (sizeof (edge) * num_edges);
6728 /* Follow successors of the entry block, and register these edges. */
6729 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
6731 elist->index_to_edge[num_edges] = e;
6735 for (x = 0; x < n_basic_blocks; x++)
6737 basic_block bb = BASIC_BLOCK (x);
6739 /* Follow all successors of blocks, and register these edges. */
6740 for (e = bb->succ; e; e = e->succ_next)
6742 elist->index_to_edge[num_edges] = e;
6749 /* This function free's memory associated with an edge list. */
6752 free_edge_list (elist)
6753 struct edge_list *elist;
6757 free (elist->index_to_edge);
6762 /* This function provides debug output showing an edge list. */
6765 print_edge_list (f, elist)
6767 struct edge_list *elist;
6770 fprintf (f, "Compressed edge list, %d BBs + entry & exit, and %d edges\n",
6771 elist->num_blocks - 2, elist->num_edges);
6773 for (x = 0; x < elist->num_edges; x++)
6775 fprintf (f, " %-4d - edge(", x);
6776 if (INDEX_EDGE_PRED_BB (elist, x) == ENTRY_BLOCK_PTR)
6777 fprintf (f, "entry,");
6779 fprintf (f, "%d,", INDEX_EDGE_PRED_BB (elist, x)->index);
6781 if (INDEX_EDGE_SUCC_BB (elist, x) == EXIT_BLOCK_PTR)
6782 fprintf (f, "exit)\n");
6784 fprintf (f, "%d)\n", INDEX_EDGE_SUCC_BB (elist, x)->index);
6788 /* This function provides an internal consistency check of an edge list,
6789 verifying that all edges are present, and that there are no
6793 verify_edge_list (f, elist)
6795 struct edge_list *elist;
6797 int x, pred, succ, index;
6800 for (x = 0; x < n_basic_blocks; x++)
6802 basic_block bb = BASIC_BLOCK (x);
6804 for (e = bb->succ; e; e = e->succ_next)
6806 pred = e->src->index;
6807 succ = e->dest->index;
6808 index = EDGE_INDEX (elist, e->src, e->dest);
6809 if (index == EDGE_INDEX_NO_EDGE)
6811 fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
6814 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
6815 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
6816 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
6817 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
6818 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
6819 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
6822 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
6824 pred = e->src->index;
6825 succ = e->dest->index;
6826 index = EDGE_INDEX (elist, e->src, e->dest);
6827 if (index == EDGE_INDEX_NO_EDGE)
6829 fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
6832 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
6833 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
6834 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
6835 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
6836 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
6837 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
6839 /* We've verified that all the edges are in the list, no lets make sure
6840 there are no spurious edges in the list. */
6842 for (pred = 0; pred < n_basic_blocks; pred++)
6843 for (succ = 0; succ < n_basic_blocks; succ++)
6845 basic_block p = BASIC_BLOCK (pred);
6846 basic_block s = BASIC_BLOCK (succ);
6850 for (e = p->succ; e; e = e->succ_next)
6856 for (e = s->pred; e; e = e->pred_next)
6862 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
6863 == EDGE_INDEX_NO_EDGE && found_edge != 0)
6864 fprintf (f, "*** Edge (%d, %d) appears to not have an index\n",
6866 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
6867 != EDGE_INDEX_NO_EDGE && found_edge == 0)
6868 fprintf (f, "*** Edge (%d, %d) has index %d, but there is no edge\n",
6869 pred, succ, EDGE_INDEX (elist, BASIC_BLOCK (pred),
6870 BASIC_BLOCK (succ)));
6872 for (succ = 0; succ < n_basic_blocks; succ++)
6874 basic_block p = ENTRY_BLOCK_PTR;
6875 basic_block s = BASIC_BLOCK (succ);
6879 for (e = p->succ; e; e = e->succ_next)
6885 for (e = s->pred; e; e = e->pred_next)
6891 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
6892 == EDGE_INDEX_NO_EDGE && found_edge != 0)
6893 fprintf (f, "*** Edge (entry, %d) appears to not have an index\n",
6895 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
6896 != EDGE_INDEX_NO_EDGE && found_edge == 0)
6897 fprintf (f, "*** Edge (entry, %d) has index %d, but no edge exists\n",
6898 succ, EDGE_INDEX (elist, ENTRY_BLOCK_PTR,
6899 BASIC_BLOCK (succ)));
6901 for (pred = 0; pred < n_basic_blocks; pred++)
6903 basic_block p = BASIC_BLOCK (pred);
6904 basic_block s = EXIT_BLOCK_PTR;
6908 for (e = p->succ; e; e = e->succ_next)
6914 for (e = s->pred; e; e = e->pred_next)
6920 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
6921 == EDGE_INDEX_NO_EDGE && found_edge != 0)
6922 fprintf (f, "*** Edge (%d, exit) appears to not have an index\n",
6924 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
6925 != EDGE_INDEX_NO_EDGE && found_edge == 0)
6926 fprintf (f, "*** Edge (%d, exit) has index %d, but no edge exists\n",
6927 pred, EDGE_INDEX (elist, BASIC_BLOCK (pred),
6932 /* This routine will determine what, if any, edge there is between
6933 a specified predecessor and successor. */
6936 find_edge_index (edge_list, pred, succ)
6937 struct edge_list *edge_list;
6938 basic_block pred, succ;
6941 for (x = 0; x < NUM_EDGES (edge_list); x++)
6943 if (INDEX_EDGE_PRED_BB (edge_list, x) == pred
6944 && INDEX_EDGE_SUCC_BB (edge_list, x) == succ)
6947 return (EDGE_INDEX_NO_EDGE);
6950 /* This function will remove an edge from the flow graph. */
6956 edge last_pred = NULL;
6957 edge last_succ = NULL;
6959 basic_block src, dest;
6962 for (tmp = src->succ; tmp && tmp != e; tmp = tmp->succ_next)
6968 last_succ->succ_next = e->succ_next;
6970 src->succ = e->succ_next;
6972 for (tmp = dest->pred; tmp && tmp != e; tmp = tmp->pred_next)
6978 last_pred->pred_next = e->pred_next;
6980 dest->pred = e->pred_next;
6986 /* This routine will remove any fake successor edges for a basic block.
6987 When the edge is removed, it is also removed from whatever predecessor
6991 remove_fake_successors (bb)
6995 for (e = bb->succ; e;)
6999 if ((tmp->flags & EDGE_FAKE) == EDGE_FAKE)
7004 /* This routine will remove all fake edges from the flow graph. If
7005 we remove all fake successors, it will automatically remove all
7006 fake predecessors. */
7009 remove_fake_edges ()
7013 for (x = 0; x < n_basic_blocks; x++)
7014 remove_fake_successors (BASIC_BLOCK (x));
7016 /* We've handled all successors except the entry block's. */
7017 remove_fake_successors (ENTRY_BLOCK_PTR);
7020 /* This function will add a fake edge between any block which has no
7021 successors, and the exit block. Some data flow equations require these
7025 add_noreturn_fake_exit_edges ()
7029 for (x = 0; x < n_basic_blocks; x++)
7030 if (BASIC_BLOCK (x)->succ == NULL)
7031 make_edge (NULL, BASIC_BLOCK (x), EXIT_BLOCK_PTR, EDGE_FAKE);
7034 /* This function adds a fake edge between any infinite loops to the
7035 exit block. Some optimizations require a path from each node to
7038 See also Morgan, Figure 3.10, pp. 82-83.
7040 The current implementation is ugly, not attempting to minimize the
7041 number of inserted fake edges. To reduce the number of fake edges
7042 to insert, add fake edges from _innermost_ loops containing only
7043 nodes not reachable from the exit block. */
7046 connect_infinite_loops_to_exit ()
7048 basic_block unvisited_block;
7050 /* Perform depth-first search in the reverse graph to find nodes
7051 reachable from the exit block. */
7052 struct depth_first_search_dsS dfs_ds;
7054 flow_dfs_compute_reverse_init (&dfs_ds);
7055 flow_dfs_compute_reverse_add_bb (&dfs_ds, EXIT_BLOCK_PTR);
7057 /* Repeatedly add fake edges, updating the unreachable nodes. */
7060 unvisited_block = flow_dfs_compute_reverse_execute (&dfs_ds);
7061 if (!unvisited_block)
7063 make_edge (NULL, unvisited_block, EXIT_BLOCK_PTR, EDGE_FAKE);
7064 flow_dfs_compute_reverse_add_bb (&dfs_ds, unvisited_block);
7067 flow_dfs_compute_reverse_finish (&dfs_ds);
7072 /* Redirect an edge's successor from one block to another. */
7075 redirect_edge_succ (e, new_succ)
7077 basic_block new_succ;
7081 /* Disconnect the edge from the old successor block. */
7082 for (pe = &e->dest->pred; *pe != e; pe = &(*pe)->pred_next)
7084 *pe = (*pe)->pred_next;
7086 /* Reconnect the edge to the new successor block. */
7087 e->pred_next = new_succ->pred;
7092 /* Redirect an edge's predecessor from one block to another. */
7095 redirect_edge_pred (e, new_pred)
7097 basic_block new_pred;
7101 /* Disconnect the edge from the old predecessor block. */
7102 for (pe = &e->src->succ; *pe != e; pe = &(*pe)->succ_next)
7104 *pe = (*pe)->succ_next;
7106 /* Reconnect the edge to the new predecessor block. */
7107 e->succ_next = new_pred->succ;
7112 /* Dump the list of basic blocks in the bitmap NODES. */
7115 flow_nodes_print (str, nodes, file)
7117 const sbitmap nodes;
7122 fprintf (file, "%s { ", str);
7123 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {fprintf (file, "%d ", node);});
7124 fputs ("}\n", file);
7127 /* Dump the list of exiting edges in the array EDGES. */
7130 flow_exits_print (str, edges, num_edges, file)
7138 fprintf (file, "%s { ", str);
7139 for (i = 0; i < num_edges; i++)
7140 fprintf (file, "%d->%d ", edges[i]->src->index, edges[i]->dest->index);
7141 fputs ("}\n", file);
7144 /* Dump loop related CFG information. */
7147 flow_loops_cfg_dump (loops, file)
7148 const struct loops *loops;
7153 if (! loops->num || ! file || ! loops->cfg.dom)
7156 for (i = 0; i < n_basic_blocks; i++)
7160 fprintf (file, ";; %d succs { ", i);
7161 for (succ = BASIC_BLOCK (i)->succ; succ; succ = succ->succ_next)
7162 fprintf (file, "%d ", succ->dest->index);
7163 flow_nodes_print ("} dom", loops->cfg.dom[i], file);
7166 /* Dump the DFS node order. */
7167 if (loops->cfg.dfs_order)
7169 fputs (";; DFS order: ", file);
7170 for (i = 0; i < n_basic_blocks; i++)
7171 fprintf (file, "%d ", loops->cfg.dfs_order[i]);
7174 /* Dump the reverse completion node order. */
7175 if (loops->cfg.rc_order)
7177 fputs (";; RC order: ", file);
7178 for (i = 0; i < n_basic_blocks; i++)
7179 fprintf (file, "%d ", loops->cfg.rc_order[i]);
7184 /* Return non-zero if the nodes of LOOP are a subset of OUTER. */
7187 flow_loop_nested_p (outer, loop)
7191 return sbitmap_a_subset_b_p (loop->nodes, outer->nodes);
7194 /* Dump the loop information specified by LOOPS to the stream FILE. */
7197 flow_loops_dump (loops, file, verbose)
7198 const struct loops *loops;
7205 num_loops = loops->num;
7206 if (! num_loops || ! file)
7209 fprintf (file, ";; %d loops found, %d levels\n",
7210 num_loops, loops->levels);
7212 for (i = 0; i < num_loops; i++)
7214 struct loop *loop = &loops->array[i];
7216 fprintf (file, ";; loop %d (%d to %d):\n;; header %d, latch %d, pre-header %d, depth %d, level %d, outer %ld\n",
7217 i, INSN_UID (loop->header->head), INSN_UID (loop->latch->end),
7218 loop->header->index, loop->latch->index,
7219 loop->pre_header ? loop->pre_header->index : -1,
7220 loop->depth, loop->level,
7221 (long) (loop->outer ? (loop->outer - loops->array) : -1));
7222 fprintf (file, ";; %d", loop->num_nodes);
7223 flow_nodes_print (" nodes", loop->nodes, file);
7224 fprintf (file, ";; %d", loop->num_exits);
7225 flow_exits_print (" exits", loop->exits, loop->num_exits, file);
7231 for (j = 0; j < i; j++)
7233 struct loop *oloop = &loops->array[j];
7235 if (loop->header == oloop->header)
7240 smaller = loop->num_nodes < oloop->num_nodes;
7242 /* If the union of LOOP and OLOOP is different than
7243 the larger of LOOP and OLOOP then LOOP and OLOOP
7244 must be disjoint. */
7245 disjoint = ! flow_loop_nested_p (smaller ? loop : oloop,
7246 smaller ? oloop : loop);
7248 ";; loop header %d shared by loops %d, %d %s\n",
7249 loop->header->index, i, j,
7250 disjoint ? "disjoint" : "nested");
7257 /* Print diagnostics to compare our concept of a loop with
7258 what the loop notes say. */
7259 if (GET_CODE (PREV_INSN (loop->first->head)) != NOTE
7260 || NOTE_LINE_NUMBER (PREV_INSN (loop->first->head))
7261 != NOTE_INSN_LOOP_BEG)
7262 fprintf (file, ";; No NOTE_INSN_LOOP_BEG at %d\n",
7263 INSN_UID (PREV_INSN (loop->first->head)));
7264 if (GET_CODE (NEXT_INSN (loop->last->end)) != NOTE
7265 || NOTE_LINE_NUMBER (NEXT_INSN (loop->last->end))
7266 != NOTE_INSN_LOOP_END)
7267 fprintf (file, ";; No NOTE_INSN_LOOP_END at %d\n",
7268 INSN_UID (NEXT_INSN (loop->last->end)));
7273 flow_loops_cfg_dump (loops, file);
7276 /* Free all the memory allocated for LOOPS. */
7279 flow_loops_free (loops)
7280 struct loops *loops;
7289 /* Free the loop descriptors. */
7290 for (i = 0; i < loops->num; i++)
7292 struct loop *loop = &loops->array[i];
7295 sbitmap_free (loop->nodes);
7299 free (loops->array);
7300 loops->array = NULL;
7303 sbitmap_vector_free (loops->cfg.dom);
7304 if (loops->cfg.dfs_order)
7305 free (loops->cfg.dfs_order);
7307 sbitmap_free (loops->shared_headers);
7311 /* Find the exits from the loop using the bitmap of loop nodes NODES
7312 and store in EXITS array. Return the number of exits from the
7316 flow_loop_exits_find (nodes, exits)
7317 const sbitmap nodes;
7326 /* Check all nodes within the loop to see if there are any
7327 successors not in the loop. Note that a node may have multiple
7330 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
7331 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
7333 basic_block dest = e->dest;
7335 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
7343 *exits = (edge *) xmalloc (num_exits * sizeof (edge *));
7345 /* Store all exiting edges into an array. */
7347 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
7348 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
7350 basic_block dest = e->dest;
7352 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
7353 (*exits)[num_exits++] = e;
7360 /* Find the nodes contained within the loop with header HEADER and
7361 latch LATCH and store in NODES. Return the number of nodes within
7365 flow_loop_nodes_find (header, latch, nodes)
7374 stack = (basic_block *) xmalloc (n_basic_blocks * sizeof (basic_block));
7377 /* Start with only the loop header in the set of loop nodes. */
7378 sbitmap_zero (nodes);
7379 SET_BIT (nodes, header->index);
7381 header->loop_depth++;
7383 /* Push the loop latch on to the stack. */
7384 if (! TEST_BIT (nodes, latch->index))
7386 SET_BIT (nodes, latch->index);
7387 latch->loop_depth++;
7389 stack[sp++] = latch;
7398 for (e = node->pred; e; e = e->pred_next)
7400 basic_block ancestor = e->src;
7402 /* If each ancestor not marked as part of loop, add to set of
7403 loop nodes and push on to stack. */
7404 if (ancestor != ENTRY_BLOCK_PTR
7405 && ! TEST_BIT (nodes, ancestor->index))
7407 SET_BIT (nodes, ancestor->index);
7408 ancestor->loop_depth++;
7410 stack[sp++] = ancestor;
7418 /* Compute the depth first search order and store in the array
7419 DFS_ORDER if non-zero, marking the nodes visited in VISITED. If
7420 RC_ORDER is non-zero, return the reverse completion number for each
7421 node. Returns the number of nodes visited. A depth first search
7422 tries to get as far away from the starting point as quickly as
7426 flow_depth_first_order_compute (dfs_order, rc_order)
7433 int rcnum = n_basic_blocks - 1;
7436 /* Allocate stack for back-tracking up CFG. */
7437 stack = (edge *) xmalloc ((n_basic_blocks + 1) * sizeof (edge));
7440 /* Allocate bitmap to track nodes that have been visited. */
7441 visited = sbitmap_alloc (n_basic_blocks);
7443 /* None of the nodes in the CFG have been visited yet. */
7444 sbitmap_zero (visited);
7446 /* Push the first edge on to the stack. */
7447 stack[sp++] = ENTRY_BLOCK_PTR->succ;
7455 /* Look at the edge on the top of the stack. */
7460 /* Check if the edge destination has been visited yet. */
7461 if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index))
7463 /* Mark that we have visited the destination. */
7464 SET_BIT (visited, dest->index);
7467 dfs_order[dfsnum++] = dest->index;
7471 /* Since the DEST node has been visited for the first
7472 time, check its successors. */
7473 stack[sp++] = dest->succ;
7477 /* There are no successors for the DEST node so assign
7478 its reverse completion number. */
7480 rc_order[rcnum--] = dest->index;
7485 if (! e->succ_next && src != ENTRY_BLOCK_PTR)
7487 /* There are no more successors for the SRC node
7488 so assign its reverse completion number. */
7490 rc_order[rcnum--] = src->index;
7494 stack[sp - 1] = e->succ_next;
7501 sbitmap_free (visited);
7503 /* The number of nodes visited should not be greater than
7505 if (dfsnum > n_basic_blocks)
7508 /* There are some nodes left in the CFG that are unreachable. */
7509 if (dfsnum < n_basic_blocks)
7514 /* Compute the depth first search order on the _reverse_ graph and
7515 store in the array DFS_ORDER, marking the nodes visited in VISITED.
7516 Returns the number of nodes visited.
7518 The computation is split into three pieces:
7520 flow_dfs_compute_reverse_init () creates the necessary data
7523 flow_dfs_compute_reverse_add_bb () adds a basic block to the data
7524 structures. The block will start the search.
7526 flow_dfs_compute_reverse_execute () continues (or starts) the
7527 search using the block on the top of the stack, stopping when the
7530 flow_dfs_compute_reverse_finish () destroys the necessary data
7533 Thus, the user will probably call ..._init(), call ..._add_bb() to
7534 add a beginning basic block to the stack, call ..._execute(),
7535 possibly add another bb to the stack and again call ..._execute(),
7536 ..., and finally call _finish(). */
7538 /* Initialize the data structures used for depth-first search on the
7539 reverse graph. If INITIALIZE_STACK is nonzero, the exit block is
7540 added to the basic block stack. DATA is the current depth-first
7541 search context. If INITIALIZE_STACK is non-zero, there is an
7542 element on the stack. */
7545 flow_dfs_compute_reverse_init (data)
7546 depth_first_search_ds data;
7548 /* Allocate stack for back-tracking up CFG. */
7550 (basic_block *) xmalloc ((n_basic_blocks - (INVALID_BLOCK + 1))
7551 * sizeof (basic_block));
7554 /* Allocate bitmap to track nodes that have been visited. */
7555 data->visited_blocks = sbitmap_alloc (n_basic_blocks - (INVALID_BLOCK + 1));
7557 /* None of the nodes in the CFG have been visited yet. */
7558 sbitmap_zero (data->visited_blocks);
7563 /* Add the specified basic block to the top of the dfs data
7564 structures. When the search continues, it will start at the
7568 flow_dfs_compute_reverse_add_bb (data, bb)
7569 depth_first_search_ds data;
7572 data->stack[data->sp++] = bb;
7576 /* Continue the depth-first search through the reverse graph starting
7577 with the block at the stack's top and ending when the stack is
7578 empty. Visited nodes are marked. Returns an unvisited basic
7579 block, or NULL if there is none available. */
7582 flow_dfs_compute_reverse_execute (data)
7583 depth_first_search_ds data;
7589 while (data->sp > 0)
7591 bb = data->stack[--data->sp];
7593 /* Mark that we have visited this node. */
7594 if (!TEST_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1)))
7596 SET_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1));
7598 /* Perform depth-first search on adjacent vertices. */
7599 for (e = bb->pred; e; e = e->pred_next)
7600 flow_dfs_compute_reverse_add_bb (data, e->src);
7604 /* Determine if there are unvisited basic blocks. */
7605 for (i = n_basic_blocks - (INVALID_BLOCK + 1); --i >= 0;)
7606 if (!TEST_BIT (data->visited_blocks, i))
7607 return BASIC_BLOCK (i + (INVALID_BLOCK + 1));
7611 /* Destroy the data structures needed for depth-first search on the
7615 flow_dfs_compute_reverse_finish (data)
7616 depth_first_search_ds data;
7619 sbitmap_free (data->visited_blocks);
7623 /* Return the block for the pre-header of the loop with header
7624 HEADER where DOM specifies the dominator information. Return NULL if
7625 there is no pre-header. */
7628 flow_loop_pre_header_find (header, dom)
7632 basic_block pre_header;
7635 /* If block p is a predecessor of the header and is the only block
7636 that the header does not dominate, then it is the pre-header. */
7638 for (e = header->pred; e; e = e->pred_next)
7640 basic_block node = e->src;
7642 if (node != ENTRY_BLOCK_PTR
7643 && ! TEST_BIT (dom[node->index], header->index))
7645 if (pre_header == NULL)
7649 /* There are multiple edges into the header from outside
7650 the loop so there is no pre-header block. */
7659 /* Add LOOP to the loop hierarchy tree where PREVLOOP was the loop
7660 previously added. The insertion algorithm assumes that the loops
7661 are added in the order found by a depth first search of the CFG. */
7664 flow_loop_tree_node_add (prevloop, loop)
7665 struct loop *prevloop;
7669 if (flow_loop_nested_p (prevloop, loop))
7671 prevloop->inner = loop;
7672 loop->outer = prevloop;
7676 while (prevloop->outer)
7678 if (flow_loop_nested_p (prevloop->outer, loop))
7680 prevloop->next = loop;
7681 loop->outer = prevloop->outer;
7684 prevloop = prevloop->outer;
7687 prevloop->next = loop;
7691 /* Build the loop hierarchy tree for LOOPS. */
7694 flow_loops_tree_build (loops)
7695 struct loops *loops;
7700 num_loops = loops->num;
7704 /* Root the loop hierarchy tree with the first loop found.
7705 Since we used a depth first search this should be the
7707 loops->tree = &loops->array[0];
7708 loops->tree->outer = loops->tree->inner = loops->tree->next = NULL;
7710 /* Add the remaining loops to the tree. */
7711 for (i = 1; i < num_loops; i++)
7712 flow_loop_tree_node_add (&loops->array[i - 1], &loops->array[i]);
7715 /* Helper function to compute loop nesting depth and enclosed loop level
7716 for the natural loop specified by LOOP at the loop depth DEPTH.
7717 Returns the loop level. */
7720 flow_loop_level_compute (loop, depth)
7730 /* Traverse loop tree assigning depth and computing level as the
7731 maximum level of all the inner loops of this loop. The loop
7732 level is equivalent to the height of the loop in the loop tree
7733 and corresponds to the number of enclosed loop levels (including
7735 for (inner = loop->inner; inner; inner = inner->next)
7739 ilevel = flow_loop_level_compute (inner, depth + 1) + 1;
7744 loop->level = level;
7745 loop->depth = depth;
7749 /* Compute the loop nesting depth and enclosed loop level for the loop
7750 hierarchy tree specfied by LOOPS. Return the maximum enclosed loop
7754 flow_loops_level_compute (loops)
7755 struct loops *loops;
7761 /* Traverse all the outer level loops. */
7762 for (loop = loops->tree; loop; loop = loop->next)
7764 level = flow_loop_level_compute (loop, 1);
7771 /* Find all the natural loops in the function and save in LOOPS structure
7772 and recalculate loop_depth information in basic block structures.
7773 Return the number of natural loops found. */
7776 flow_loops_find (loops)
7777 struct loops *loops;
7789 loops->array = NULL;
7794 /* Taking care of this degenerate case makes the rest of
7795 this code simpler. */
7796 if (n_basic_blocks == 0)
7799 /* Compute the dominators. */
7800 dom = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
7801 compute_flow_dominators (dom, NULL);
7803 /* Count the number of loop edges (back edges). This should be the
7804 same as the number of natural loops. Also clear the loop_depth
7805 and as we work from inner->outer in a loop nest we call
7806 find_loop_nodes_find which will increment loop_depth for nodes
7807 within the current loop, which happens to enclose inner loops. */
7810 for (b = 0; b < n_basic_blocks; b++)
7812 BASIC_BLOCK (b)->loop_depth = 0;
7813 for (e = BASIC_BLOCK (b)->pred; e; e = e->pred_next)
7815 basic_block latch = e->src;
7817 /* Look for back edges where a predecessor is dominated
7818 by this block. A natural loop has a single entry
7819 node (header) that dominates all the nodes in the
7820 loop. It also has single back edge to the header
7821 from a latch node. Note that multiple natural loops
7822 may share the same header. */
7823 if (latch != ENTRY_BLOCK_PTR && TEST_BIT (dom[latch->index], b))
7830 /* Compute depth first search order of the CFG so that outer
7831 natural loops will be found before inner natural loops. */
7832 dfs_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
7833 rc_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
7834 flow_depth_first_order_compute (dfs_order, rc_order);
7836 /* Allocate loop structures. */
7838 = (struct loop *) xcalloc (num_loops, sizeof (struct loop));
7840 headers = sbitmap_alloc (n_basic_blocks);
7841 sbitmap_zero (headers);
7843 loops->shared_headers = sbitmap_alloc (n_basic_blocks);
7844 sbitmap_zero (loops->shared_headers);
7846 /* Find and record information about all the natural loops
7849 for (b = 0; b < n_basic_blocks; b++)
7853 /* Search the nodes of the CFG in DFS order that we can find
7854 outer loops first. */
7855 header = BASIC_BLOCK (rc_order[b]);
7857 /* Look for all the possible latch blocks for this header. */
7858 for (e = header->pred; e; e = e->pred_next)
7860 basic_block latch = e->src;
7862 /* Look for back edges where a predecessor is dominated
7863 by this block. A natural loop has a single entry
7864 node (header) that dominates all the nodes in the
7865 loop. It also has single back edge to the header
7866 from a latch node. Note that multiple natural loops
7867 may share the same header. */
7868 if (latch != ENTRY_BLOCK_PTR
7869 && TEST_BIT (dom[latch->index], header->index))
7873 loop = loops->array + num_loops;
7875 loop->header = header;
7876 loop->latch = latch;
7877 loop->num = num_loops;
7879 /* Keep track of blocks that are loop headers so
7880 that we can tell which loops should be merged. */
7881 if (TEST_BIT (headers, header->index))
7882 SET_BIT (loops->shared_headers, header->index);
7883 SET_BIT (headers, header->index);
7885 /* Find nodes contained within the loop. */
7886 loop->nodes = sbitmap_alloc (n_basic_blocks);
7888 = flow_loop_nodes_find (header, latch, loop->nodes);
7890 /* Compute first and last blocks within the loop.
7891 These are often the same as the loop header and
7892 loop latch respectively, but this is not always
7895 = BASIC_BLOCK (sbitmap_first_set_bit (loop->nodes));
7897 = BASIC_BLOCK (sbitmap_last_set_bit (loop->nodes));
7899 /* Find edges which exit the loop. Note that a node
7900 may have several exit edges. */
7902 = flow_loop_exits_find (loop->nodes, &loop->exits);
7904 /* Look to see if the loop has a pre-header node. */
7905 loop->pre_header = flow_loop_pre_header_find (header, dom);
7912 /* Natural loops with shared headers may either be disjoint or
7913 nested. Disjoint loops with shared headers cannot be inner
7914 loops and should be merged. For now just mark loops that share
7916 for (i = 0; i < num_loops; i++)
7917 if (TEST_BIT (loops->shared_headers, loops->array[i].header->index))
7918 loops->array[i].shared = 1;
7920 sbitmap_free (headers);
7923 loops->num = num_loops;
7925 /* Save CFG derived information to avoid recomputing it. */
7926 loops->cfg.dom = dom;
7927 loops->cfg.dfs_order = dfs_order;
7928 loops->cfg.rc_order = rc_order;
7930 /* Build the loop hierarchy tree. */
7931 flow_loops_tree_build (loops);
7933 /* Assign the loop nesting depth and enclosed loop level for each
7935 loops->levels = flow_loops_level_compute (loops);
7940 /* Return non-zero if edge E enters header of LOOP from outside of LOOP. */
7943 flow_loop_outside_edge_p (loop, e)
7944 const struct loop *loop;
7947 if (e->dest != loop->header)
7949 return (e->src == ENTRY_BLOCK_PTR)
7950 || ! TEST_BIT (loop->nodes, e->src->index);
7953 /* Clear LOG_LINKS fields of insns in a chain.
7954 Also clear the global_live_at_{start,end} fields of the basic block
7958 clear_log_links (insns)
7964 for (i = insns; i; i = NEXT_INSN (i))
7968 for (b = 0; b < n_basic_blocks; b++)
7970 basic_block bb = BASIC_BLOCK (b);
7972 bb->global_live_at_start = NULL;
7973 bb->global_live_at_end = NULL;
7976 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
7977 EXIT_BLOCK_PTR->global_live_at_start = NULL;
7980 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
7981 correspond to the hard registers, if any, set in that map. This
7982 could be done far more efficiently by having all sorts of special-cases
7983 with moving single words, but probably isn't worth the trouble. */
7986 reg_set_to_hard_reg_set (to, from)
7992 EXECUTE_IF_SET_IN_BITMAP
7995 if (i >= FIRST_PSEUDO_REGISTER)
7997 SET_HARD_REG_BIT (*to, i);