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. */
23 /* This file contains the data flow analysis pass of the compiler. It
24 computes data flow information which tells combine_instructions
25 which insns to consider combining and controls register allocation.
27 Additional data flow information that is too bulky to record is
28 generated during the analysis, and is used at that time to create
29 autoincrement and autodecrement addressing.
31 The first step is dividing the function into basic blocks.
32 find_basic_blocks does this. Then life_analysis determines
33 where each register is live and where it is dead.
35 ** find_basic_blocks **
37 find_basic_blocks divides the current function's rtl into basic
38 blocks and constructs the CFG. The blocks are recorded in the
39 basic_block_info array; the CFG exists in the edge structures
40 referenced by the blocks.
42 find_basic_blocks also finds any unreachable loops and deletes them.
46 life_analysis is called immediately after find_basic_blocks.
47 It uses the basic block information to determine where each
48 hard or pseudo register is live.
50 ** live-register info **
52 The information about where each register is live is in two parts:
53 the REG_NOTES of insns, and the vector basic_block->global_live_at_start.
55 basic_block->global_live_at_start has an element for each basic
56 block, and the element is a bit-vector with a bit for each hard or
57 pseudo register. The bit is 1 if the register is live at the
58 beginning of the basic block.
60 Two types of elements can be added to an insn's REG_NOTES.
61 A REG_DEAD note is added to an insn's REG_NOTES for any register
62 that meets both of two conditions: The value in the register is not
63 needed in subsequent insns and the insn does not replace the value in
64 the register (in the case of multi-word hard registers, the value in
65 each register must be replaced by the insn to avoid a REG_DEAD note).
67 In the vast majority of cases, an object in a REG_DEAD note will be
68 used somewhere in the insn. The (rare) exception to this is if an
69 insn uses a multi-word hard register and only some of the registers are
70 needed in subsequent insns. In that case, REG_DEAD notes will be
71 provided for those hard registers that are not subsequently needed.
72 Partial REG_DEAD notes of this type do not occur when an insn sets
73 only some of the hard registers used in such a multi-word operand;
74 omitting REG_DEAD notes for objects stored in an insn is optional and
75 the desire to do so does not justify the complexity of the partial
78 REG_UNUSED notes are added for each register that is set by the insn
79 but is unused subsequently (if every register set by the insn is unused
80 and the insn does not reference memory or have some other side-effect,
81 the insn is deleted instead). If only part of a multi-word hard
82 register is used in a subsequent insn, REG_UNUSED notes are made for
83 the parts that will not be used.
85 To determine which registers are live after any insn, one can
86 start from the beginning of the basic block and scan insns, noting
87 which registers are set by each insn and which die there.
89 ** Other actions of life_analysis **
91 life_analysis sets up the LOG_LINKS fields of insns because the
92 information needed to do so is readily available.
94 life_analysis deletes insns whose only effect is to store a value
97 life_analysis notices cases where a reference to a register as
98 a memory address can be combined with a preceding or following
99 incrementation or decrementation of the register. The separate
100 instruction to increment or decrement is deleted and the address
101 is changed to a POST_INC or similar rtx.
103 Each time an incrementing or decrementing address is created,
104 a REG_INC element is added to the insn's REG_NOTES list.
106 life_analysis fills in certain vectors containing information about
107 register usage: REG_N_REFS, REG_N_DEATHS, REG_N_SETS, REG_LIVE_LENGTH,
108 REG_N_CALLS_CROSSED and REG_BASIC_BLOCK.
110 life_analysis sets current_function_sp_is_unchanging if the function
111 doesn't modify the stack pointer. */
115 Split out from life_analysis:
116 - local property discovery (bb->local_live, bb->local_set)
117 - global property computation
119 - pre/post modify transformation
127 #include "basic-block.h"
128 #include "insn-config.h"
130 #include "hard-reg-set.h"
133 #include "function.h"
137 #include "insn-flags.h"
141 #include "splay-tree.h"
143 #define obstack_chunk_alloc xmalloc
144 #define obstack_chunk_free free
147 /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
148 the stack pointer does not matter. The value is tested only in
149 functions that have frame pointers.
150 No definition is equivalent to always zero. */
151 #ifndef EXIT_IGNORE_STACK
152 #define EXIT_IGNORE_STACK 0
155 #ifndef HAVE_epilogue
156 #define HAVE_epilogue 0
158 #ifndef HAVE_prologue
159 #define HAVE_prologue 0
161 #ifndef HAVE_sibcall_epilogue
162 #define HAVE_sibcall_epilogue 0
165 /* The contents of the current function definition are allocated
166 in this obstack, and all are freed at the end of the function.
167 For top-level functions, this is temporary_obstack.
168 Separate obstacks are made for nested functions. */
170 extern struct obstack *function_obstack;
172 /* Number of basic blocks in the current function. */
176 /* Number of edges in the current function. */
180 /* The basic block array. */
182 varray_type basic_block_info;
184 /* The special entry and exit blocks. */
186 struct basic_block_def entry_exit_blocks[2]
191 NULL, /* local_set */
192 NULL, /* global_live_at_start */
193 NULL, /* global_live_at_end */
195 ENTRY_BLOCK, /* index */
197 -1, -1 /* eh_beg, eh_end */
204 NULL, /* local_set */
205 NULL, /* global_live_at_start */
206 NULL, /* global_live_at_end */
208 EXIT_BLOCK, /* index */
210 -1, -1 /* eh_beg, eh_end */
214 /* Nonzero if the second flow pass has completed. */
217 /* Maximum register number used in this function, plus one. */
221 /* Indexed by n, giving various register information */
223 varray_type reg_n_info;
225 /* Size of a regset for the current function,
226 in (1) bytes and (2) elements. */
231 /* Regset of regs live when calls to `setjmp'-like functions happen. */
232 /* ??? Does this exist only for the setjmp-clobbered warning message? */
234 regset regs_live_at_setjmp;
236 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
237 that have to go in the same hard reg.
238 The first two regs in the list are a pair, and the next two
239 are another pair, etc. */
242 /* Set of registers that may be eliminable. These are handled specially
243 in updating regs_ever_live. */
245 static HARD_REG_SET elim_reg_set;
247 /* The basic block structure for every insn, indexed by uid. */
249 varray_type basic_block_for_insn;
251 /* The labels mentioned in non-jump rtl. Valid during find_basic_blocks. */
252 /* ??? Should probably be using LABEL_NUSES instead. It would take a
253 bit of surgery to be able to use or co-opt the routines in jump. */
255 static rtx label_value_list;
257 /* Holds information for tracking conditional register life information. */
258 struct reg_cond_life_info
260 /* An EXPR_LIST of conditions under which a register is dead. */
263 /* ??? Could store mask of bytes that are dead, so that we could finally
264 track lifetimes of multi-word registers accessed via subregs. */
267 /* For use in communicating between propagate_block and its subroutines.
268 Holds all information needed to compute life and def-use information. */
270 struct propagate_block_info
272 /* The basic block we're considering. */
275 /* Bit N is set if register N is conditionally or unconditionally live. */
278 /* Bit N is set if register N is set this insn. */
281 /* Element N is the next insn that uses (hard or pseudo) register N
282 within the current basic block; or zero, if there is no such insn. */
285 /* Contains a list of all the MEMs we are tracking for dead store
289 /* If non-null, record the set of registers set in the basic block. */
292 #ifdef HAVE_conditional_execution
293 /* Indexed by register number, holds a reg_cond_life_info for each
294 register that is not unconditionally live or dead. */
295 splay_tree reg_cond_dead;
297 /* Bit N is set if register N is in an expression in reg_cond_dead. */
301 /* Non-zero if the value of CC0 is live. */
304 /* Flags controling the set of information propagate_block collects. */
308 /* Forward declarations */
309 static int count_basic_blocks PARAMS ((rtx));
310 static rtx find_basic_blocks_1 PARAMS ((rtx));
311 static void clear_edges PARAMS ((void));
312 static void make_edges PARAMS ((rtx));
313 static void make_label_edge PARAMS ((sbitmap *, basic_block,
315 static void make_eh_edge PARAMS ((sbitmap *, eh_nesting_info *,
316 basic_block, rtx, int));
317 static void mark_critical_edges PARAMS ((void));
318 static void move_stray_eh_region_notes PARAMS ((void));
319 static void record_active_eh_regions PARAMS ((rtx));
321 static void commit_one_edge_insertion PARAMS ((edge));
323 static void delete_unreachable_blocks PARAMS ((void));
324 static void delete_eh_regions PARAMS ((void));
325 static int can_delete_note_p PARAMS ((rtx));
326 static void expunge_block PARAMS ((basic_block));
327 static int can_delete_label_p PARAMS ((rtx));
328 static int merge_blocks_move_predecessor_nojumps PARAMS ((basic_block,
330 static int merge_blocks_move_successor_nojumps PARAMS ((basic_block,
332 static int merge_blocks PARAMS ((edge,basic_block,basic_block));
333 static void try_merge_blocks PARAMS ((void));
334 static void tidy_fallthru_edges PARAMS ((void));
335 static int verify_wide_reg_1 PARAMS ((rtx *, void *));
336 static void verify_wide_reg PARAMS ((int, rtx, rtx));
337 static void verify_local_live_at_start PARAMS ((regset, basic_block));
338 static int set_noop_p PARAMS ((rtx));
339 static int noop_move_p PARAMS ((rtx));
340 static void delete_noop_moves PARAMS ((rtx));
341 static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
342 static void notice_stack_pointer_modification PARAMS ((rtx));
343 static void mark_reg PARAMS ((rtx, void *));
344 static void mark_regs_live_at_end PARAMS ((regset));
345 static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
346 static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
347 static void propagate_block_delete_insn PARAMS ((basic_block, rtx));
348 static rtx propagate_block_delete_libcall PARAMS ((basic_block, rtx, rtx));
349 static int insn_dead_p PARAMS ((struct propagate_block_info *,
351 static int libcall_dead_p PARAMS ((struct propagate_block_info *,
353 static void mark_set_regs PARAMS ((struct propagate_block_info *,
355 static void mark_set_1 PARAMS ((struct propagate_block_info *,
356 enum rtx_code, rtx, rtx,
358 #ifdef HAVE_conditional_execution
359 static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
361 static void free_reg_cond_life_info PARAMS ((splay_tree_value));
362 static int flush_reg_cond_reg_1 PARAMS ((splay_tree_node, void *));
363 static void flush_reg_cond_reg PARAMS ((struct propagate_block_info *,
365 static rtx ior_reg_cond PARAMS ((rtx, rtx));
366 static rtx not_reg_cond PARAMS ((rtx));
367 static rtx nand_reg_cond PARAMS ((rtx, rtx));
370 static void find_auto_inc PARAMS ((struct propagate_block_info *,
372 static int try_pre_increment_1 PARAMS ((struct propagate_block_info *,
374 static int try_pre_increment PARAMS ((rtx, rtx, HOST_WIDE_INT));
376 static void mark_used_reg PARAMS ((struct propagate_block_info *,
378 static void mark_used_regs PARAMS ((struct propagate_block_info *,
380 void dump_flow_info PARAMS ((FILE *));
381 void debug_flow_info PARAMS ((void));
382 static void dump_edge_info PARAMS ((FILE *, edge, int));
384 static void invalidate_mems_from_autoinc PARAMS ((struct propagate_block_info *,
386 static void remove_fake_successors PARAMS ((basic_block));
387 static void flow_nodes_print PARAMS ((const char *, const sbitmap, FILE *));
388 static void flow_exits_print PARAMS ((const char *, const edge *, int, FILE *));
389 static void flow_loops_cfg_dump PARAMS ((const struct loops *, FILE *));
390 static int flow_loop_nested_p PARAMS ((struct loop *, struct loop *));
391 static int flow_loop_exits_find PARAMS ((const sbitmap, edge **));
392 static int flow_loop_nodes_find PARAMS ((basic_block, basic_block, sbitmap));
393 static int flow_depth_first_order_compute PARAMS ((int *));
394 static basic_block flow_loop_pre_header_find PARAMS ((basic_block, const sbitmap *));
395 static void flow_loop_tree_node_add PARAMS ((struct loop *, struct loop *));
396 static void flow_loops_tree_build PARAMS ((struct loops *));
397 static int flow_loop_level_compute PARAMS ((struct loop *, int));
398 static int flow_loops_level_compute PARAMS ((struct loops *));
400 /* Find basic blocks of the current function.
401 F is the first insn of the function and NREGS the number of register
405 find_basic_blocks (f, nregs, file)
407 int nregs ATTRIBUTE_UNUSED;
408 FILE *file ATTRIBUTE_UNUSED;
412 /* Flush out existing data. */
413 if (basic_block_info != NULL)
419 /* Clear bb->aux on all extant basic blocks. We'll use this as a
420 tag for reuse during create_basic_block, just in case some pass
421 copies around basic block notes improperly. */
422 for (i = 0; i < n_basic_blocks; ++i)
423 BASIC_BLOCK (i)->aux = NULL;
425 VARRAY_FREE (basic_block_info);
428 n_basic_blocks = count_basic_blocks (f);
430 /* Size the basic block table. The actual structures will be allocated
431 by find_basic_blocks_1, since we want to keep the structure pointers
432 stable across calls to find_basic_blocks. */
433 /* ??? This whole issue would be much simpler if we called find_basic_blocks
434 exactly once, and thereafter we don't have a single long chain of
435 instructions at all until close to the end of compilation when we
436 actually lay them out. */
438 VARRAY_BB_INIT (basic_block_info, n_basic_blocks, "basic_block_info");
440 label_value_list = find_basic_blocks_1 (f);
442 /* Record the block to which an insn belongs. */
443 /* ??? This should be done another way, by which (perhaps) a label is
444 tagged directly with the basic block that it starts. It is used for
445 more than that currently, but IMO that is the only valid use. */
447 max_uid = get_max_uid ();
449 /* Leave space for insns life_analysis makes in some cases for auto-inc.
450 These cases are rare, so we don't need too much space. */
451 max_uid += max_uid / 10;
454 compute_bb_for_insn (max_uid);
456 /* Discover the edges of our cfg. */
457 record_active_eh_regions (f);
458 make_edges (label_value_list);
460 /* Do very simple cleanup now, for the benefit of code that runs between
461 here and cleanup_cfg, e.g. thread_prologue_and_epilogue_insns. */
462 tidy_fallthru_edges ();
464 mark_critical_edges ();
466 #ifdef ENABLE_CHECKING
471 /* Count the basic blocks of the function. */
474 count_basic_blocks (f)
478 register RTX_CODE prev_code;
479 register int count = 0;
481 int call_had_abnormal_edge = 0;
483 prev_code = JUMP_INSN;
484 for (insn = f; insn; insn = NEXT_INSN (insn))
486 register RTX_CODE code = GET_CODE (insn);
488 if (code == CODE_LABEL
489 || (GET_RTX_CLASS (code) == 'i'
490 && (prev_code == JUMP_INSN
491 || prev_code == BARRIER
492 || (prev_code == CALL_INSN && call_had_abnormal_edge))))
495 /* Record whether this call created an edge. */
496 if (code == CALL_INSN)
498 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
499 int region = (note ? INTVAL (XEXP (note, 0)) : 1);
501 call_had_abnormal_edge = 0;
503 /* If there is an EH region or rethrow, we have an edge. */
504 if ((eh_region && region > 0)
505 || find_reg_note (insn, REG_EH_RETHROW, NULL_RTX))
506 call_had_abnormal_edge = 1;
507 else if (nonlocal_goto_handler_labels && region >= 0)
508 /* If there is a nonlocal goto label and the specified
509 region number isn't -1, we have an edge. (0 means
510 no throw, but might have a nonlocal goto). */
511 call_had_abnormal_edge = 1;
516 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
518 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
522 /* The rest of the compiler works a bit smoother when we don't have to
523 check for the edge case of do-nothing functions with no basic blocks. */
526 emit_insn (gen_rtx_USE (VOIDmode, const0_rtx));
533 /* Find all basic blocks of the function whose first insn is F.
535 Collect and return a list of labels whose addresses are taken. This
536 will be used in make_edges for use with computed gotos. */
539 find_basic_blocks_1 (f)
542 register rtx insn, next;
544 rtx bb_note = NULL_RTX;
545 rtx eh_list = NULL_RTX;
546 rtx label_value_list = NULL_RTX;
550 /* We process the instructions in a slightly different way than we did
551 previously. This is so that we see a NOTE_BASIC_BLOCK after we have
552 closed out the previous block, so that it gets attached at the proper
553 place. Since this form should be equivalent to the previous,
554 count_basic_blocks continues to use the old form as a check. */
556 for (insn = f; insn; insn = next)
558 enum rtx_code code = GET_CODE (insn);
560 next = NEXT_INSN (insn);
566 int kind = NOTE_LINE_NUMBER (insn);
568 /* Keep a LIFO list of the currently active exception notes. */
569 if (kind == NOTE_INSN_EH_REGION_BEG)
570 eh_list = alloc_INSN_LIST (insn, eh_list);
571 else if (kind == NOTE_INSN_EH_REGION_END)
575 eh_list = XEXP (eh_list, 1);
576 free_INSN_LIST_node (t);
579 /* Look for basic block notes with which to keep the
580 basic_block_info pointers stable. Unthread the note now;
581 we'll put it back at the right place in create_basic_block.
582 Or not at all if we've already found a note in this block. */
583 else if (kind == NOTE_INSN_BASIC_BLOCK)
585 if (bb_note == NULL_RTX)
588 next = flow_delete_insn (insn);
594 /* A basic block starts at a label. If we've closed one off due
595 to a barrier or some such, no need to do it again. */
596 if (head != NULL_RTX)
598 /* While we now have edge lists with which other portions of
599 the compiler might determine a call ending a basic block
600 does not imply an abnormal edge, it will be a bit before
601 everything can be updated. So continue to emit a noop at
602 the end of such a block. */
603 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
605 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
606 end = emit_insn_after (nop, end);
609 create_basic_block (i++, head, end, bb_note);
617 /* A basic block ends at a jump. */
618 if (head == NULL_RTX)
622 /* ??? Make a special check for table jumps. The way this
623 happens is truly and amazingly gross. We are about to
624 create a basic block that contains just a code label and
625 an addr*vec jump insn. Worse, an addr_diff_vec creates
626 its own natural loop.
628 Prevent this bit of brain damage, pasting things together
629 correctly in make_edges.
631 The correct solution involves emitting the table directly
632 on the tablejump instruction as a note, or JUMP_LABEL. */
634 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
635 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
643 goto new_bb_inclusive;
646 /* A basic block ends at a barrier. It may be that an unconditional
647 jump already closed the basic block -- no need to do it again. */
648 if (head == NULL_RTX)
651 /* While we now have edge lists with which other portions of the
652 compiler might determine a call ending a basic block does not
653 imply an abnormal edge, it will be a bit before everything can
654 be updated. So continue to emit a noop at the end of such a
656 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
658 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
659 end = emit_insn_after (nop, end);
661 goto new_bb_exclusive;
665 /* Record whether this call created an edge. */
666 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
667 int region = (note ? INTVAL (XEXP (note, 0)) : 1);
668 int call_has_abnormal_edge = 0;
670 /* If there is an EH region or rethrow, we have an edge. */
671 if ((eh_list && region > 0)
672 || find_reg_note (insn, REG_EH_RETHROW, NULL_RTX))
673 call_has_abnormal_edge = 1;
674 else if (nonlocal_goto_handler_labels && region >= 0)
675 /* If there is a nonlocal goto label and the specified
676 region number isn't -1, we have an edge. (0 means
677 no throw, but might have a nonlocal goto). */
678 call_has_abnormal_edge = 1;
680 /* A basic block ends at a call that can either throw or
681 do a non-local goto. */
682 if (call_has_abnormal_edge)
685 if (head == NULL_RTX)
690 create_basic_block (i++, head, end, bb_note);
691 head = end = NULL_RTX;
699 if (GET_RTX_CLASS (code) == 'i')
701 if (head == NULL_RTX)
708 if (GET_RTX_CLASS (code) == 'i')
712 /* Make a list of all labels referred to other than by jumps
713 (which just don't have the REG_LABEL notes).
715 Make a special exception for labels followed by an ADDR*VEC,
716 as this would be a part of the tablejump setup code.
718 Make a special exception for the eh_return_stub_label, which
719 we know isn't part of any otherwise visible control flow. */
721 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
722 if (REG_NOTE_KIND (note) == REG_LABEL)
724 rtx lab = XEXP (note, 0), next;
726 if (lab == eh_return_stub_label)
728 else if ((next = next_nonnote_insn (lab)) != NULL
729 && GET_CODE (next) == JUMP_INSN
730 && (GET_CODE (PATTERN (next)) == ADDR_VEC
731 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
735 = alloc_EXPR_LIST (0, XEXP (note, 0), label_value_list);
740 if (head != NULL_RTX)
741 create_basic_block (i++, head, end, bb_note);
743 if (i != n_basic_blocks)
746 return label_value_list;
749 /* Tidy the CFG by deleting unreachable code and whatnot. */
755 delete_unreachable_blocks ();
756 move_stray_eh_region_notes ();
757 record_active_eh_regions (f);
759 mark_critical_edges ();
761 /* Kill the data we won't maintain. */
762 label_value_list = NULL_RTX;
765 /* Create a new basic block consisting of the instructions between
766 HEAD and END inclusive. Reuses the note and basic block struct
767 in BB_NOTE, if any. */
770 create_basic_block (index, head, end, bb_note)
772 rtx head, end, bb_note;
777 && ! RTX_INTEGRATED_P (bb_note)
778 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
781 /* If we found an existing note, thread it back onto the chain. */
783 if (GET_CODE (head) == CODE_LABEL)
784 add_insn_after (bb_note, head);
787 add_insn_before (bb_note, head);
793 /* Otherwise we must create a note and a basic block structure.
794 Since we allow basic block structs in rtl, give the struct
795 the same lifetime by allocating it off the function obstack
796 rather than using malloc. */
798 bb = (basic_block) obstack_alloc (function_obstack, sizeof (*bb));
799 memset (bb, 0, sizeof (*bb));
801 if (GET_CODE (head) == CODE_LABEL)
802 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
805 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
808 NOTE_BASIC_BLOCK (bb_note) = bb;
811 /* Always include the bb note in the block. */
812 if (NEXT_INSN (end) == bb_note)
818 BASIC_BLOCK (index) = bb;
820 /* Tag the block so that we know it has been used when considering
821 other basic block notes. */
825 /* Records the basic block struct in BB_FOR_INSN, for every instruction
826 indexed by INSN_UID. MAX is the size of the array. */
829 compute_bb_for_insn (max)
834 if (basic_block_for_insn)
835 VARRAY_FREE (basic_block_for_insn);
836 VARRAY_BB_INIT (basic_block_for_insn, max, "basic_block_for_insn");
838 for (i = 0; i < n_basic_blocks; ++i)
840 basic_block bb = BASIC_BLOCK (i);
847 int uid = INSN_UID (insn);
849 VARRAY_BB (basic_block_for_insn, uid) = bb;
852 insn = NEXT_INSN (insn);
857 /* Free the memory associated with the edge structures. */
865 for (i = 0; i < n_basic_blocks; ++i)
867 basic_block bb = BASIC_BLOCK (i);
869 for (e = bb->succ; e ; e = n)
879 for (e = ENTRY_BLOCK_PTR->succ; e ; e = n)
885 ENTRY_BLOCK_PTR->succ = 0;
886 EXIT_BLOCK_PTR->pred = 0;
891 /* Identify the edges between basic blocks.
893 NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks
894 that are otherwise unreachable may be reachable with a non-local goto.
896 BB_EH_END is an array indexed by basic block number in which we record
897 the list of exception regions active at the end of the basic block. */
900 make_edges (label_value_list)
901 rtx label_value_list;
904 eh_nesting_info *eh_nest_info = init_eh_nesting_info ();
905 sbitmap *edge_cache = NULL;
907 /* Assume no computed jump; revise as we create edges. */
908 current_function_has_computed_jump = 0;
910 /* Heavy use of computed goto in machine-generated code can lead to
911 nearly fully-connected CFGs. In that case we spend a significant
912 amount of time searching the edge lists for duplicates. */
913 if (forced_labels || label_value_list)
915 edge_cache = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
916 sbitmap_vector_zero (edge_cache, n_basic_blocks);
919 /* By nature of the way these get numbered, block 0 is always the entry. */
920 make_edge (edge_cache, ENTRY_BLOCK_PTR, BASIC_BLOCK (0), EDGE_FALLTHRU);
922 for (i = 0; i < n_basic_blocks; ++i)
924 basic_block bb = BASIC_BLOCK (i);
927 int force_fallthru = 0;
929 /* Examine the last instruction of the block, and discover the
930 ways we can leave the block. */
933 code = GET_CODE (insn);
936 if (code == JUMP_INSN)
940 /* ??? Recognize a tablejump and do the right thing. */
941 if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
942 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
943 && GET_CODE (tmp) == JUMP_INSN
944 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
945 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
950 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
951 vec = XVEC (PATTERN (tmp), 0);
953 vec = XVEC (PATTERN (tmp), 1);
955 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
956 make_label_edge (edge_cache, bb,
957 XEXP (RTVEC_ELT (vec, j), 0), 0);
959 /* Some targets (eg, ARM) emit a conditional jump that also
960 contains the out-of-range target. Scan for these and
961 add an edge if necessary. */
962 if ((tmp = single_set (insn)) != NULL
963 && SET_DEST (tmp) == pc_rtx
964 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
965 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF)
966 make_label_edge (edge_cache, bb,
967 XEXP (XEXP (SET_SRC (tmp), 2), 0), 0);
969 #ifdef CASE_DROPS_THROUGH
970 /* Silly VAXen. The ADDR_VEC is going to be in the way of
971 us naturally detecting fallthru into the next block. */
976 /* If this is a computed jump, then mark it as reaching
977 everything on the label_value_list and forced_labels list. */
978 else if (computed_jump_p (insn))
980 current_function_has_computed_jump = 1;
982 for (x = label_value_list; x; x = XEXP (x, 1))
983 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
985 for (x = forced_labels; x; x = XEXP (x, 1))
986 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
989 /* Returns create an exit out. */
990 else if (returnjump_p (insn))
991 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, 0);
993 /* Otherwise, we have a plain conditional or unconditional jump. */
996 if (! JUMP_LABEL (insn))
998 make_label_edge (edge_cache, bb, JUMP_LABEL (insn), 0);
1002 /* If this is a sibling call insn, then this is in effect a
1003 combined call and return, and so we need an edge to the
1004 exit block. No need to worry about EH edges, since we
1005 wouldn't have created the sibling call in the first place. */
1007 if (code == CALL_INSN && SIBLING_CALL_P (insn))
1008 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, 0);
1011 /* If this is a CALL_INSN, then mark it as reaching the active EH
1012 handler for this CALL_INSN. If we're handling asynchronous
1013 exceptions then any insn can reach any of the active handlers.
1015 Also mark the CALL_INSN as reaching any nonlocal goto handler. */
1017 if (code == CALL_INSN || asynchronous_exceptions)
1019 /* Add any appropriate EH edges. We do this unconditionally
1020 since there may be a REG_EH_REGION or REG_EH_RETHROW note
1021 on the call, and this needn't be within an EH region. */
1022 make_eh_edge (edge_cache, eh_nest_info, bb, insn, bb->eh_end);
1024 /* If we have asynchronous exceptions, do the same for *all*
1025 exception regions active in the block. */
1026 if (asynchronous_exceptions
1027 && bb->eh_beg != bb->eh_end)
1029 if (bb->eh_beg >= 0)
1030 make_eh_edge (edge_cache, eh_nest_info, bb,
1031 NULL_RTX, bb->eh_beg);
1033 for (x = bb->head; x != bb->end; x = NEXT_INSN (x))
1034 if (GET_CODE (x) == NOTE
1035 && (NOTE_LINE_NUMBER (x) == NOTE_INSN_EH_REGION_BEG
1036 || NOTE_LINE_NUMBER (x) == NOTE_INSN_EH_REGION_END))
1038 int region = NOTE_EH_HANDLER (x);
1039 make_eh_edge (edge_cache, eh_nest_info, bb,
1044 if (code == CALL_INSN && nonlocal_goto_handler_labels)
1046 /* ??? This could be made smarter: in some cases it's possible
1047 to tell that certain calls will not do a nonlocal goto.
1049 For example, if the nested functions that do the nonlocal
1050 gotos do not have their addresses taken, then only calls to
1051 those functions or to other nested functions that use them
1052 could possibly do nonlocal gotos. */
1053 /* We do know that a REG_EH_REGION note with a value less
1054 than 0 is guaranteed not to perform a non-local goto. */
1055 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
1056 if (!note || INTVAL (XEXP (note, 0)) >= 0)
1057 for (x = nonlocal_goto_handler_labels; x ; x = XEXP (x, 1))
1058 make_label_edge (edge_cache, bb, XEXP (x, 0),
1059 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1063 /* We know something about the structure of the function __throw in
1064 libgcc2.c. It is the only function that ever contains eh_stub
1065 labels. It modifies its return address so that the last block
1066 returns to one of the eh_stub labels within it. So we have to
1067 make additional edges in the flow graph. */
1068 if (i + 1 == n_basic_blocks && eh_return_stub_label != 0)
1069 make_label_edge (edge_cache, bb, eh_return_stub_label, EDGE_EH);
1071 /* Find out if we can drop through to the next block. */
1072 insn = next_nonnote_insn (insn);
1073 if (!insn || (i + 1 == n_basic_blocks && force_fallthru))
1074 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU);
1075 else if (i + 1 < n_basic_blocks)
1077 rtx tmp = BLOCK_HEAD (i + 1);
1078 if (GET_CODE (tmp) == NOTE)
1079 tmp = next_nonnote_insn (tmp);
1080 if (force_fallthru || insn == tmp)
1081 make_edge (edge_cache, bb, BASIC_BLOCK (i + 1), EDGE_FALLTHRU);
1085 free_eh_nesting_info (eh_nest_info);
1087 sbitmap_vector_free (edge_cache);
1090 /* Create an edge between two basic blocks. FLAGS are auxiliary information
1091 about the edge that is accumulated between calls. */
1094 make_edge (edge_cache, src, dst, flags)
1095 sbitmap *edge_cache;
1096 basic_block src, dst;
1102 /* Don't bother with edge cache for ENTRY or EXIT; there aren't that
1103 many edges to them, and we didn't allocate memory for it. */
1104 use_edge_cache = (edge_cache
1105 && src != ENTRY_BLOCK_PTR
1106 && dst != EXIT_BLOCK_PTR);
1108 /* Make sure we don't add duplicate edges. */
1109 if (! use_edge_cache || TEST_BIT (edge_cache[src->index], dst->index))
1110 for (e = src->succ; e ; e = e->succ_next)
1117 e = (edge) xcalloc (1, sizeof (*e));
1120 e->succ_next = src->succ;
1121 e->pred_next = dst->pred;
1130 SET_BIT (edge_cache[src->index], dst->index);
1133 /* Create an edge from a basic block to a label. */
1136 make_label_edge (edge_cache, src, label, flags)
1137 sbitmap *edge_cache;
1142 if (GET_CODE (label) != CODE_LABEL)
1145 /* If the label was never emitted, this insn is junk, but avoid a
1146 crash trying to refer to BLOCK_FOR_INSN (label). This can happen
1147 as a result of a syntax error and a diagnostic has already been
1150 if (INSN_UID (label) == 0)
1153 make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags);
1156 /* Create the edges generated by INSN in REGION. */
1159 make_eh_edge (edge_cache, eh_nest_info, src, insn, region)
1160 sbitmap *edge_cache;
1161 eh_nesting_info *eh_nest_info;
1166 handler_info **handler_list;
1169 is_call = (insn && GET_CODE (insn) == CALL_INSN ? EDGE_ABNORMAL_CALL : 0);
1170 num = reachable_handlers (region, eh_nest_info, insn, &handler_list);
1173 make_label_edge (edge_cache, src, handler_list[num]->handler_label,
1174 EDGE_ABNORMAL | EDGE_EH | is_call);
1178 /* EH_REGION notes appearing between basic blocks is ambiguous, and even
1179 dangerous if we intend to move basic blocks around. Move such notes
1180 into the following block. */
1183 move_stray_eh_region_notes ()
1188 if (n_basic_blocks < 2)
1191 b2 = BASIC_BLOCK (n_basic_blocks - 1);
1192 for (i = n_basic_blocks - 2; i >= 0; --i, b2 = b1)
1194 rtx insn, next, list = NULL_RTX;
1196 b1 = BASIC_BLOCK (i);
1197 for (insn = NEXT_INSN (b1->end); insn != b2->head; insn = next)
1199 next = NEXT_INSN (insn);
1200 if (GET_CODE (insn) == NOTE
1201 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG
1202 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
1204 /* Unlink from the insn chain. */
1205 NEXT_INSN (PREV_INSN (insn)) = next;
1206 PREV_INSN (next) = PREV_INSN (insn);
1209 NEXT_INSN (insn) = list;
1214 if (list == NULL_RTX)
1217 /* Find where to insert these things. */
1219 if (GET_CODE (insn) == CODE_LABEL)
1220 insn = NEXT_INSN (insn);
1224 next = NEXT_INSN (list);
1225 add_insn_after (list, insn);
1231 /* Recompute eh_beg/eh_end for each basic block. */
1234 record_active_eh_regions (f)
1237 rtx insn, eh_list = NULL_RTX;
1239 basic_block bb = BASIC_BLOCK (0);
1241 for (insn = f; insn ; insn = NEXT_INSN (insn))
1243 if (bb->head == insn)
1244 bb->eh_beg = (eh_list ? NOTE_EH_HANDLER (XEXP (eh_list, 0)) : -1);
1246 if (GET_CODE (insn) == NOTE)
1248 int kind = NOTE_LINE_NUMBER (insn);
1249 if (kind == NOTE_INSN_EH_REGION_BEG)
1250 eh_list = alloc_INSN_LIST (insn, eh_list);
1251 else if (kind == NOTE_INSN_EH_REGION_END)
1253 rtx t = XEXP (eh_list, 1);
1254 free_INSN_LIST_node (eh_list);
1259 if (bb->end == insn)
1261 bb->eh_end = (eh_list ? NOTE_EH_HANDLER (XEXP (eh_list, 0)) : -1);
1263 if (i == n_basic_blocks)
1265 bb = BASIC_BLOCK (i);
1270 /* Identify critical edges and set the bits appropriately. */
1273 mark_critical_edges ()
1275 int i, n = n_basic_blocks;
1278 /* We begin with the entry block. This is not terribly important now,
1279 but could be if a front end (Fortran) implemented alternate entry
1281 bb = ENTRY_BLOCK_PTR;
1288 /* (1) Critical edges must have a source with multiple successors. */
1289 if (bb->succ && bb->succ->succ_next)
1291 for (e = bb->succ; e ; e = e->succ_next)
1293 /* (2) Critical edges must have a destination with multiple
1294 predecessors. Note that we know there is at least one
1295 predecessor -- the edge we followed to get here. */
1296 if (e->dest->pred->pred_next)
1297 e->flags |= EDGE_CRITICAL;
1299 e->flags &= ~EDGE_CRITICAL;
1304 for (e = bb->succ; e ; e = e->succ_next)
1305 e->flags &= ~EDGE_CRITICAL;
1310 bb = BASIC_BLOCK (i);
1314 /* Split a (typically critical) edge. Return the new block.
1315 Abort on abnormal edges.
1317 ??? The code generally expects to be called on critical edges.
1318 The case of a block ending in an unconditional jump to a
1319 block with multiple predecessors is not handled optimally. */
1322 split_edge (edge_in)
1325 basic_block old_pred, bb, old_succ;
1330 /* Abnormal edges cannot be split. */
1331 if ((edge_in->flags & EDGE_ABNORMAL) != 0)
1334 old_pred = edge_in->src;
1335 old_succ = edge_in->dest;
1337 /* Remove the existing edge from the destination's pred list. */
1340 for (pp = &old_succ->pred; *pp != edge_in; pp = &(*pp)->pred_next)
1342 *pp = edge_in->pred_next;
1343 edge_in->pred_next = NULL;
1346 /* Create the new structures. */
1347 bb = (basic_block) obstack_alloc (function_obstack, sizeof (*bb));
1348 edge_out = (edge) xcalloc (1, sizeof (*edge_out));
1351 memset (bb, 0, sizeof (*bb));
1353 /* ??? This info is likely going to be out of date very soon. */
1354 if (old_succ->global_live_at_start)
1356 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (function_obstack);
1357 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (function_obstack);
1358 COPY_REG_SET (bb->global_live_at_start, old_succ->global_live_at_start);
1359 COPY_REG_SET (bb->global_live_at_end, old_succ->global_live_at_start);
1364 bb->succ = edge_out;
1367 edge_in->flags &= ~EDGE_CRITICAL;
1369 edge_out->pred_next = old_succ->pred;
1370 edge_out->succ_next = NULL;
1372 edge_out->dest = old_succ;
1373 edge_out->flags = EDGE_FALLTHRU;
1374 edge_out->probability = REG_BR_PROB_BASE;
1376 old_succ->pred = edge_out;
1378 /* Tricky case -- if there existed a fallthru into the successor
1379 (and we're not it) we must add a new unconditional jump around
1380 the new block we're actually interested in.
1382 Further, if that edge is critical, this means a second new basic
1383 block must be created to hold it. In order to simplify correct
1384 insn placement, do this before we touch the existing basic block
1385 ordering for the block we were really wanting. */
1386 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1389 for (e = edge_out->pred_next; e ; e = e->pred_next)
1390 if (e->flags & EDGE_FALLTHRU)
1395 basic_block jump_block;
1398 if ((e->flags & EDGE_CRITICAL) == 0
1399 && e->src != ENTRY_BLOCK_PTR)
1401 /* Non critical -- we can simply add a jump to the end
1402 of the existing predecessor. */
1403 jump_block = e->src;
1407 /* We need a new block to hold the jump. The simplest
1408 way to do the bulk of the work here is to recursively
1410 jump_block = split_edge (e);
1411 e = jump_block->succ;
1414 /* Now add the jump insn ... */
1415 pos = emit_jump_insn_after (gen_jump (old_succ->head),
1417 jump_block->end = pos;
1418 if (basic_block_for_insn)
1419 set_block_for_insn (pos, jump_block);
1420 emit_barrier_after (pos);
1422 /* ... let jump know that label is in use, ... */
1423 JUMP_LABEL (pos) = old_succ->head;
1424 ++LABEL_NUSES (old_succ->head);
1426 /* ... and clear fallthru on the outgoing edge. */
1427 e->flags &= ~EDGE_FALLTHRU;
1429 /* Continue splitting the interesting edge. */
1433 /* Place the new block just in front of the successor. */
1434 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
1435 if (old_succ == EXIT_BLOCK_PTR)
1436 j = n_basic_blocks - 1;
1438 j = old_succ->index;
1439 for (i = n_basic_blocks - 1; i > j; --i)
1441 basic_block tmp = BASIC_BLOCK (i - 1);
1442 BASIC_BLOCK (i) = tmp;
1445 BASIC_BLOCK (i) = bb;
1448 /* Create the basic block note.
1450 Where we place the note can have a noticable impact on the generated
1451 code. Consider this cfg:
1462 If we need to insert an insn on the edge from block 0 to block 1,
1463 we want to ensure the instructions we insert are outside of any
1464 loop notes that physically sit between block 0 and block 1. Otherwise
1465 we confuse the loop optimizer into thinking the loop is a phony. */
1466 if (old_succ != EXIT_BLOCK_PTR
1467 && PREV_INSN (old_succ->head)
1468 && GET_CODE (PREV_INSN (old_succ->head)) == NOTE
1469 && NOTE_LINE_NUMBER (PREV_INSN (old_succ->head)) == NOTE_INSN_LOOP_BEG)
1470 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
1471 PREV_INSN (old_succ->head));
1472 else if (old_succ != EXIT_BLOCK_PTR)
1473 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, old_succ->head);
1475 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
1476 NOTE_BASIC_BLOCK (bb_note) = bb;
1477 bb->head = bb->end = bb_note;
1479 /* Not quite simple -- for non-fallthru edges, we must adjust the
1480 predecessor's jump instruction to target our new block. */
1481 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1483 rtx tmp, insn = old_pred->end;
1484 rtx old_label = old_succ->head;
1485 rtx new_label = gen_label_rtx ();
1487 if (GET_CODE (insn) != JUMP_INSN)
1490 /* ??? Recognize a tablejump and adjust all matching cases. */
1491 if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1492 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1493 && GET_CODE (tmp) == JUMP_INSN
1494 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1495 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1500 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1501 vec = XVEC (PATTERN (tmp), 0);
1503 vec = XVEC (PATTERN (tmp), 1);
1505 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1506 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
1508 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (VOIDmode, new_label);
1509 --LABEL_NUSES (old_label);
1510 ++LABEL_NUSES (new_label);
1513 /* Handle casesi dispatch insns */
1514 if ((tmp = single_set (insn)) != NULL
1515 && SET_DEST (tmp) == pc_rtx
1516 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1517 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
1518 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
1520 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (VOIDmode,
1522 --LABEL_NUSES (old_label);
1523 ++LABEL_NUSES (new_label);
1528 /* This would have indicated an abnormal edge. */
1529 if (computed_jump_p (insn))
1532 /* A return instruction can't be redirected. */
1533 if (returnjump_p (insn))
1536 /* If the insn doesn't go where we think, we're confused. */
1537 if (JUMP_LABEL (insn) != old_label)
1540 redirect_jump (insn, new_label);
1543 emit_label_before (new_label, bb_note);
1544 bb->head = new_label;
1550 /* Queue instructions for insertion on an edge between two basic blocks.
1551 The new instructions and basic blocks (if any) will not appear in the
1552 CFG until commit_edge_insertions is called. */
1555 insert_insn_on_edge (pattern, e)
1559 /* We cannot insert instructions on an abnormal critical edge.
1560 It will be easier to find the culprit if we die now. */
1561 if ((e->flags & (EDGE_ABNORMAL|EDGE_CRITICAL))
1562 == (EDGE_ABNORMAL|EDGE_CRITICAL))
1565 if (e->insns == NULL_RTX)
1568 push_to_sequence (e->insns);
1570 emit_insn (pattern);
1572 e->insns = get_insns ();
1576 /* Update the CFG for the instructions queued on edge E. */
1579 commit_one_edge_insertion (e)
1582 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp;
1585 /* Pull the insns off the edge now since the edge might go away. */
1587 e->insns = NULL_RTX;
1589 /* Figure out where to put these things. If the destination has
1590 one predecessor, insert there. Except for the exit block. */
1591 if (e->dest->pred->pred_next == NULL
1592 && e->dest != EXIT_BLOCK_PTR)
1596 /* Get the location correct wrt a code label, and "nice" wrt
1597 a basic block note, and before everything else. */
1599 if (GET_CODE (tmp) == CODE_LABEL)
1600 tmp = NEXT_INSN (tmp);
1601 if (GET_CODE (tmp) == NOTE
1602 && NOTE_LINE_NUMBER (tmp) == NOTE_INSN_BASIC_BLOCK)
1603 tmp = NEXT_INSN (tmp);
1604 if (tmp == bb->head)
1607 after = PREV_INSN (tmp);
1610 /* If the source has one successor and the edge is not abnormal,
1611 insert there. Except for the entry block. */
1612 else if ((e->flags & EDGE_ABNORMAL) == 0
1613 && e->src->succ->succ_next == NULL
1614 && e->src != ENTRY_BLOCK_PTR)
1617 /* It is possible to have a non-simple jump here. Consider a target
1618 where some forms of unconditional jumps clobber a register. This
1619 happens on the fr30 for example.
1621 We know this block has a single successor, so we can just emit
1622 the queued insns before the jump. */
1623 if (GET_CODE (bb->end) == JUMP_INSN)
1629 /* We'd better be fallthru, or we've lost track of what's what. */
1630 if ((e->flags & EDGE_FALLTHRU) == 0)
1637 /* Otherwise we must split the edge. */
1640 bb = split_edge (e);
1644 /* Now that we've found the spot, do the insertion. */
1646 /* Set the new block number for these insns, if structure is allocated. */
1647 if (basic_block_for_insn)
1650 for (i = insns; i != NULL_RTX; i = NEXT_INSN (i))
1651 set_block_for_insn (i, bb);
1656 emit_insns_before (insns, before);
1657 if (before == bb->head)
1662 rtx last = emit_insns_after (insns, after);
1663 if (after == bb->end)
1667 if (GET_CODE (last) == JUMP_INSN)
1669 if (returnjump_p (last))
1671 /* ??? Remove all outgoing edges from BB and add one
1672 for EXIT. This is not currently a problem because
1673 this only happens for the (single) epilogue, which
1674 already has a fallthru edge to EXIT. */
1677 if (e->dest != EXIT_BLOCK_PTR
1678 || e->succ_next != NULL
1679 || (e->flags & EDGE_FALLTHRU) == 0)
1681 e->flags &= ~EDGE_FALLTHRU;
1683 emit_barrier_after (last);
1692 /* Update the CFG for all queued instructions. */
1695 commit_edge_insertions ()
1700 #ifdef ENABLE_CHECKING
1701 verify_flow_info ();
1705 bb = ENTRY_BLOCK_PTR;
1710 for (e = bb->succ; e ; e = next)
1712 next = e->succ_next;
1714 commit_one_edge_insertion (e);
1717 if (++i >= n_basic_blocks)
1719 bb = BASIC_BLOCK (i);
1723 /* Delete all unreachable basic blocks. */
1726 delete_unreachable_blocks ()
1728 basic_block *worklist, *tos;
1729 int deleted_handler;
1734 tos = worklist = (basic_block *) xmalloc (sizeof (basic_block) * n);
1736 /* Use basic_block->aux as a marker. Clear them all. */
1738 for (i = 0; i < n; ++i)
1739 BASIC_BLOCK (i)->aux = NULL;
1741 /* Add our starting points to the worklist. Almost always there will
1742 be only one. It isn't inconcievable that we might one day directly
1743 support Fortran alternate entry points. */
1745 for (e = ENTRY_BLOCK_PTR->succ; e ; e = e->succ_next)
1749 /* Mark the block with a handy non-null value. */
1753 /* Iterate: find everything reachable from what we've already seen. */
1755 while (tos != worklist)
1757 basic_block b = *--tos;
1759 for (e = b->succ; e ; e = e->succ_next)
1767 /* Delete all unreachable basic blocks. Count down so that we don't
1768 interfere with the block renumbering that happens in flow_delete_block. */
1770 deleted_handler = 0;
1772 for (i = n - 1; i >= 0; --i)
1774 basic_block b = BASIC_BLOCK (i);
1777 /* This block was found. Tidy up the mark. */
1780 deleted_handler |= flow_delete_block (b);
1783 tidy_fallthru_edges ();
1785 /* If we deleted an exception handler, we may have EH region begin/end
1786 blocks to remove as well. */
1787 if (deleted_handler)
1788 delete_eh_regions ();
1793 /* Find EH regions for which there is no longer a handler, and delete them. */
1796 delete_eh_regions ()
1800 update_rethrow_references ();
1802 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
1803 if (GET_CODE (insn) == NOTE)
1805 if ((NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG) ||
1806 (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
1808 int num = NOTE_EH_HANDLER (insn);
1809 /* A NULL handler indicates a region is no longer needed,
1810 as long as its rethrow label isn't used. */
1811 if (get_first_handler (num) == NULL && ! rethrow_used (num))
1813 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
1814 NOTE_SOURCE_FILE (insn) = 0;
1820 /* Return true if NOTE is not one of the ones that must be kept paired,
1821 so that we may simply delete them. */
1824 can_delete_note_p (note)
1827 return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED
1828 || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK);
1831 /* Unlink a chain of insns between START and FINISH, leaving notes
1832 that must be paired. */
1835 flow_delete_insn_chain (start, finish)
1838 /* Unchain the insns one by one. It would be quicker to delete all
1839 of these with a single unchaining, rather than one at a time, but
1840 we need to keep the NOTE's. */
1846 next = NEXT_INSN (start);
1847 if (GET_CODE (start) == NOTE && !can_delete_note_p (start))
1849 else if (GET_CODE (start) == CODE_LABEL && !can_delete_label_p (start))
1852 next = flow_delete_insn (start);
1854 if (start == finish)
1860 /* Delete the insns in a (non-live) block. We physically delete every
1861 non-deleted-note insn, and update the flow graph appropriately.
1863 Return nonzero if we deleted an exception handler. */
1865 /* ??? Preserving all such notes strikes me as wrong. It would be nice
1866 to post-process the stream to remove empty blocks, loops, ranges, etc. */
1869 flow_delete_block (b)
1872 int deleted_handler = 0;
1875 /* If the head of this block is a CODE_LABEL, then it might be the
1876 label for an exception handler which can't be reached.
1878 We need to remove the label from the exception_handler_label list
1879 and remove the associated NOTE_INSN_EH_REGION_BEG and
1880 NOTE_INSN_EH_REGION_END notes. */
1884 never_reached_warning (insn);
1886 if (GET_CODE (insn) == CODE_LABEL)
1888 rtx x, *prev = &exception_handler_labels;
1890 for (x = exception_handler_labels; x; x = XEXP (x, 1))
1892 if (XEXP (x, 0) == insn)
1894 /* Found a match, splice this label out of the EH label list. */
1895 *prev = XEXP (x, 1);
1896 XEXP (x, 1) = NULL_RTX;
1897 XEXP (x, 0) = NULL_RTX;
1899 /* Remove the handler from all regions */
1900 remove_handler (insn);
1901 deleted_handler = 1;
1904 prev = &XEXP (x, 1);
1907 /* This label may be referenced by code solely for its value, or
1908 referenced by static data, or something. We have determined
1909 that it is not reachable, but cannot delete the label itself.
1910 Save code space and continue to delete the balance of the block,
1911 along with properly updating the cfg. */
1912 if (!can_delete_label_p (insn))
1914 /* If we've only got one of these, skip the whole deleting
1917 goto no_delete_insns;
1918 insn = NEXT_INSN (insn);
1922 /* Include any jump table following the basic block. */
1924 if (GET_CODE (end) == JUMP_INSN
1925 && (tmp = JUMP_LABEL (end)) != NULL_RTX
1926 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1927 && GET_CODE (tmp) == JUMP_INSN
1928 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1929 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1932 /* Include any barrier that may follow the basic block. */
1933 tmp = next_nonnote_insn (end);
1934 if (tmp && GET_CODE (tmp) == BARRIER)
1937 /* Selectively delete the entire chain. */
1938 flow_delete_insn_chain (insn, end);
1942 /* Remove the edges into and out of this block. Note that there may
1943 indeed be edges in, if we are removing an unreachable loop. */
1947 for (e = b->pred; e ; e = next)
1949 for (q = &e->src->succ; *q != e; q = &(*q)->succ_next)
1952 next = e->pred_next;
1956 for (e = b->succ; e ; e = next)
1958 for (q = &e->dest->pred; *q != e; q = &(*q)->pred_next)
1961 next = e->succ_next;
1970 /* Remove the basic block from the array, and compact behind it. */
1973 return deleted_handler;
1976 /* Remove block B from the basic block array and compact behind it. */
1982 int i, n = n_basic_blocks;
1984 for (i = b->index; i + 1 < n; ++i)
1986 basic_block x = BASIC_BLOCK (i + 1);
1987 BASIC_BLOCK (i) = x;
1991 basic_block_info->num_elements--;
1995 /* Delete INSN by patching it out. Return the next insn. */
1998 flow_delete_insn (insn)
2001 rtx prev = PREV_INSN (insn);
2002 rtx next = NEXT_INSN (insn);
2005 PREV_INSN (insn) = NULL_RTX;
2006 NEXT_INSN (insn) = NULL_RTX;
2009 NEXT_INSN (prev) = next;
2011 PREV_INSN (next) = prev;
2013 set_last_insn (prev);
2015 if (GET_CODE (insn) == CODE_LABEL)
2016 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2018 /* If deleting a jump, decrement the use count of the label. Deleting
2019 the label itself should happen in the normal course of block merging. */
2020 if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn))
2021 LABEL_NUSES (JUMP_LABEL (insn))--;
2023 /* Also if deleting an insn that references a label. */
2024 else if ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX)
2025 LABEL_NUSES (XEXP (note, 0))--;
2030 /* True if a given label can be deleted. */
2033 can_delete_label_p (label)
2038 if (LABEL_PRESERVE_P (label))
2041 for (x = forced_labels; x ; x = XEXP (x, 1))
2042 if (label == XEXP (x, 0))
2044 for (x = label_value_list; x ; x = XEXP (x, 1))
2045 if (label == XEXP (x, 0))
2047 for (x = exception_handler_labels; x ; x = XEXP (x, 1))
2048 if (label == XEXP (x, 0))
2051 /* User declared labels must be preserved. */
2052 if (LABEL_NAME (label) != 0)
2058 /* Blocks A and B are to be merged into a single block A. The insns
2059 are already contiguous, hence `nomove'. */
2062 merge_blocks_nomove (a, b)
2066 rtx b_head, b_end, a_end;
2067 rtx del_first = NULL_RTX, del_last = NULL_RTX;
2070 /* If there was a CODE_LABEL beginning B, delete it. */
2073 if (GET_CODE (b_head) == CODE_LABEL)
2075 /* Detect basic blocks with nothing but a label. This can happen
2076 in particular at the end of a function. */
2077 if (b_head == b_end)
2079 del_first = del_last = b_head;
2080 b_head = NEXT_INSN (b_head);
2083 /* Delete the basic block note. */
2084 if (GET_CODE (b_head) == NOTE
2085 && NOTE_LINE_NUMBER (b_head) == NOTE_INSN_BASIC_BLOCK)
2087 if (b_head == b_end)
2092 b_head = NEXT_INSN (b_head);
2095 /* If there was a jump out of A, delete it. */
2097 if (GET_CODE (a_end) == JUMP_INSN)
2101 prev = prev_nonnote_insn (a_end);
2108 /* If this was a conditional jump, we need to also delete
2109 the insn that set cc0. */
2110 if (prev && sets_cc0_p (prev))
2113 prev = prev_nonnote_insn (prev);
2123 /* Delete everything marked above as well as crap that might be
2124 hanging out between the two blocks. */
2125 flow_delete_insn_chain (del_first, del_last);
2127 /* Normally there should only be one successor of A and that is B, but
2128 partway though the merge of blocks for conditional_execution we'll
2129 be merging a TEST block with THEN and ELSE successors. Free the
2130 whole lot of them and hope the caller knows what they're doing. */
2132 remove_edge (a->succ);
2134 /* Adjust the edges out of B for the new owner. */
2135 for (e = b->succ; e ; e = e->succ_next)
2139 /* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */
2140 b->pred = b->succ = NULL;
2142 /* Reassociate the insns of B with A. */
2145 if (basic_block_for_insn)
2147 BLOCK_FOR_INSN (b_head) = a;
2148 while (b_head != b_end)
2150 b_head = NEXT_INSN (b_head);
2151 BLOCK_FOR_INSN (b_head) = a;
2161 /* Blocks A and B are to be merged into a single block. A has no incoming
2162 fallthru edge, so it can be moved before B without adding or modifying
2163 any jumps (aside from the jump from A to B). */
2166 merge_blocks_move_predecessor_nojumps (a, b)
2169 rtx start, end, barrier;
2175 /* We want to delete the BARRIER after the end of the insns we are
2176 going to move. If we don't find a BARRIER, then do nothing. This
2177 can happen in some cases if we have labels we can not delete.
2179 Similarly, do nothing if we can not delete the label at the start
2180 of the target block. */
2181 barrier = next_nonnote_insn (end);
2182 if (GET_CODE (barrier) != BARRIER
2183 || (GET_CODE (b->head) == CODE_LABEL
2184 && ! can_delete_label_p (b->head)))
2187 flow_delete_insn (barrier);
2189 /* Move block and loop notes out of the chain so that we do not
2190 disturb their order.
2192 ??? A better solution would be to squeeze out all the non-nested notes
2193 and adjust the block trees appropriately. Even better would be to have
2194 a tighter connection between block trees and rtl so that this is not
2196 start = squeeze_notes (start, end);
2198 /* Scramble the insn chain. */
2199 if (end != PREV_INSN (b->head))
2200 reorder_insns (start, end, PREV_INSN (b->head));
2204 fprintf (rtl_dump_file, "Moved block %d before %d and merged.\n",
2205 a->index, b->index);
2208 /* Swap the records for the two blocks around. Although we are deleting B,
2209 A is now where B was and we want to compact the BB array from where
2211 BASIC_BLOCK(a->index) = b;
2212 BASIC_BLOCK(b->index) = a;
2214 a->index = b->index;
2217 /* Now blocks A and B are contiguous. Merge them. */
2218 merge_blocks_nomove (a, b);
2223 /* Blocks A and B are to be merged into a single block. B has no outgoing
2224 fallthru edge, so it can be moved after A without adding or modifying
2225 any jumps (aside from the jump from A to B). */
2228 merge_blocks_move_successor_nojumps (a, b)
2231 rtx start, end, barrier;
2236 /* We want to delete the BARRIER after the end of the insns we are
2237 going to move. If we don't find a BARRIER, then do nothing. This
2238 can happen in some cases if we have labels we can not delete.
2240 Similarly, do nothing if we can not delete the label at the start
2241 of the target block. */
2242 barrier = next_nonnote_insn (end);
2243 if (GET_CODE (barrier) != BARRIER
2244 || (GET_CODE (b->head) == CODE_LABEL
2245 && ! can_delete_label_p (b->head)))
2248 flow_delete_insn (barrier);
2250 /* Move block and loop notes out of the chain so that we do not
2251 disturb their order.
2253 ??? A better solution would be to squeeze out all the non-nested notes
2254 and adjust the block trees appropriately. Even better would be to have
2255 a tighter connection between block trees and rtl so that this is not
2257 start = squeeze_notes (start, end);
2259 /* Scramble the insn chain. */
2260 reorder_insns (start, end, a->end);
2262 /* Now blocks A and B are contiguous. Merge them. */
2263 merge_blocks_nomove (a, b);
2267 fprintf (rtl_dump_file, "Moved block %d after %d and merged.\n",
2268 b->index, a->index);
2274 /* Attempt to merge basic blocks that are potentially non-adjacent.
2275 Return true iff the attempt succeeded. */
2278 merge_blocks (e, b, c)
2282 /* If B has a fallthru edge to C, no need to move anything. */
2283 if (e->flags & EDGE_FALLTHRU)
2285 /* If a label still appears somewhere and we cannot delete the label,
2286 then we cannot merge the blocks. The edge was tidied already. */
2288 rtx insn, stop = NEXT_INSN (c->head);
2289 for (insn = NEXT_INSN (b->end); insn != stop; insn = NEXT_INSN (insn))
2290 if (GET_CODE (insn) == CODE_LABEL && !can_delete_label_p (insn))
2293 merge_blocks_nomove (b, c);
2297 fprintf (rtl_dump_file, "Merged %d and %d without moving.\n",
2298 b->index, c->index);
2307 int c_has_outgoing_fallthru;
2308 int b_has_incoming_fallthru;
2310 /* We must make sure to not munge nesting of exception regions,
2311 lexical blocks, and loop notes.
2313 The first is taken care of by requiring that the active eh
2314 region at the end of one block always matches the active eh
2315 region at the beginning of the next block.
2317 The later two are taken care of by squeezing out all the notes. */
2319 /* ??? A throw/catch edge (or any abnormal edge) should be rarely
2320 executed and we may want to treat blocks which have two out
2321 edges, one normal, one abnormal as only having one edge for
2322 block merging purposes. */
2324 for (tmp_edge = c->succ; tmp_edge ; tmp_edge = tmp_edge->succ_next)
2325 if (tmp_edge->flags & EDGE_FALLTHRU)
2327 c_has_outgoing_fallthru = (tmp_edge != NULL);
2329 for (tmp_edge = b->pred; tmp_edge ; tmp_edge = tmp_edge->pred_next)
2330 if (tmp_edge->flags & EDGE_FALLTHRU)
2332 b_has_incoming_fallthru = (tmp_edge != NULL);
2334 /* If B does not have an incoming fallthru, and the exception regions
2335 match, then it can be moved immediately before C without introducing
2338 C can not be the first block, so we do not have to worry about
2339 accessing a non-existent block. */
2340 d = BASIC_BLOCK (c->index - 1);
2341 if (! b_has_incoming_fallthru
2342 && d->eh_end == b->eh_beg
2343 && b->eh_end == c->eh_beg)
2344 return merge_blocks_move_predecessor_nojumps (b, c);
2346 /* Otherwise, we're going to try to move C after B. Make sure the
2347 exception regions match.
2349 If B is the last basic block, then we must not try to access the
2350 block structure for block B + 1. Luckily in that case we do not
2351 need to worry about matching exception regions. */
2352 d = (b->index + 1 < n_basic_blocks ? BASIC_BLOCK (b->index + 1) : NULL);
2353 if (b->eh_end == c->eh_beg
2354 && (d == NULL || c->eh_end == d->eh_beg))
2356 /* If C does not have an outgoing fallthru, then it can be moved
2357 immediately after B without introducing or modifying jumps. */
2358 if (! c_has_outgoing_fallthru)
2359 return merge_blocks_move_successor_nojumps (b, c);
2361 /* Otherwise, we'll need to insert an extra jump, and possibly
2362 a new block to contain it. */
2363 /* ??? Not implemented yet. */
2370 /* Top level driver for merge_blocks. */
2377 /* Attempt to merge blocks as made possible by edge removal. If a block
2378 has only one successor, and the successor has only one predecessor,
2379 they may be combined. */
2381 for (i = 0; i < n_basic_blocks; )
2383 basic_block c, b = BASIC_BLOCK (i);
2386 /* A loop because chains of blocks might be combineable. */
2387 while ((s = b->succ) != NULL
2388 && s->succ_next == NULL
2389 && (s->flags & EDGE_EH) == 0
2390 && (c = s->dest) != EXIT_BLOCK_PTR
2391 && c->pred->pred_next == NULL
2392 /* If the jump insn has side effects, we can't kill the edge. */
2393 && (GET_CODE (b->end) != JUMP_INSN
2394 || onlyjump_p (b->end))
2395 && merge_blocks (s, b, c))
2398 /* Don't get confused by the index shift caused by deleting blocks. */
2403 /* The given edge should potentially be a fallthru edge. If that is in
2404 fact true, delete the jump and barriers that are in the way. */
2407 tidy_fallthru_edge (e, b, c)
2413 /* ??? In a late-running flow pass, other folks may have deleted basic
2414 blocks by nopping out blocks, leaving multiple BARRIERs between here
2415 and the target label. They ought to be chastized and fixed.
2417 We can also wind up with a sequence of undeletable labels between
2418 one block and the next.
2420 So search through a sequence of barriers, labels, and notes for
2421 the head of block C and assert that we really do fall through. */
2423 if (next_real_insn (b->end) != next_real_insn (PREV_INSN (c->head)))
2426 /* Remove what will soon cease being the jump insn from the source block.
2427 If block B consisted only of this single jump, turn it into a deleted
2430 if (GET_CODE (q) == JUMP_INSN
2431 && (simplejump_p (q)
2432 || (b->succ == e && e->succ_next == NULL)))
2435 /* If this was a conditional jump, we need to also delete
2436 the insn that set cc0. */
2437 if (! simplejump_p (q) && condjump_p (q) && sets_cc0_p (PREV_INSN (q)))
2444 NOTE_LINE_NUMBER (q) = NOTE_INSN_DELETED;
2445 NOTE_SOURCE_FILE (q) = 0;
2448 b->end = q = PREV_INSN (q);
2451 /* Selectively unlink the sequence. */
2452 if (q != PREV_INSN (c->head))
2453 flow_delete_insn_chain (NEXT_INSN (q), PREV_INSN (c->head));
2455 e->flags |= EDGE_FALLTHRU;
2458 /* Fix up edges that now fall through, or rather should now fall through
2459 but previously required a jump around now deleted blocks. Simplify
2460 the search by only examining blocks numerically adjacent, since this
2461 is how find_basic_blocks created them. */
2464 tidy_fallthru_edges ()
2468 for (i = 1; i < n_basic_blocks; ++i)
2470 basic_block b = BASIC_BLOCK (i - 1);
2471 basic_block c = BASIC_BLOCK (i);
2474 /* We care about simple conditional or unconditional jumps with
2477 If we had a conditional branch to the next instruction when
2478 find_basic_blocks was called, then there will only be one
2479 out edge for the block which ended with the conditional
2480 branch (since we do not create duplicate edges).
2482 Furthermore, the edge will be marked as a fallthru because we
2483 merge the flags for the duplicate edges. So we do not want to
2484 check that the edge is not a FALLTHRU edge. */
2485 if ((s = b->succ) != NULL
2486 && s->succ_next == NULL
2488 /* If the jump insn has side effects, we can't tidy the edge. */
2489 && (GET_CODE (b->end) != JUMP_INSN
2490 || onlyjump_p (b->end)))
2491 tidy_fallthru_edge (s, b, c);
2495 /* Perform data flow analysis.
2496 F is the first insn of the function; FLAGS is a set of PROP_* flags
2497 to be used in accumulating flow info. */
2500 life_analysis (f, file, flags)
2505 #ifdef ELIMINABLE_REGS
2507 static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
2510 /* Record which registers will be eliminated. We use this in
2513 CLEAR_HARD_REG_SET (elim_reg_set);
2515 #ifdef ELIMINABLE_REGS
2516 for (i = 0; i < (int) (sizeof eliminables / sizeof eliminables[0]); i++)
2517 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
2519 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
2523 flags &= PROP_DEATH_NOTES | PROP_REG_INFO;
2525 /* The post-reload life analysis have (on a global basis) the same
2526 registers live as was computed by reload itself. elimination
2527 Otherwise offsets and such may be incorrect.
2529 Reload will make some registers as live even though they do not
2530 appear in the rtl. */
2531 if (reload_completed)
2532 flags &= ~PROP_REG_INFO;
2534 /* We want alias analysis information for local dead store elimination. */
2535 if (flags & PROP_SCAN_DEAD_CODE)
2536 init_alias_analysis ();
2538 /* Always remove no-op moves. Do this before other processing so
2539 that we don't have to keep re-scanning them. */
2540 delete_noop_moves (f);
2542 /* Some targets can emit simpler epilogues if they know that sp was
2543 not ever modified during the function. After reload, of course,
2544 we've already emitted the epilogue so there's no sense searching. */
2545 if (! reload_completed)
2546 notice_stack_pointer_modification (f);
2548 /* Allocate and zero out data structures that will record the
2549 data from lifetime analysis. */
2550 allocate_reg_life_data ();
2551 allocate_bb_life_data ();
2553 /* Find the set of registers live on function exit. */
2554 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
2556 /* "Update" life info from zero. It'd be nice to begin the
2557 relaxation with just the exit and noreturn blocks, but that set
2558 is not immediately handy. */
2560 if (flags & PROP_REG_INFO)
2561 memset (regs_ever_live, 0, sizeof(regs_ever_live));
2562 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
2565 if (flags & PROP_SCAN_DEAD_CODE)
2566 end_alias_analysis ();
2569 dump_flow_info (file);
2571 free_basic_block_vars (1);
2574 /* A subroutine of verify_wide_reg, called through for_each_rtx.
2575 Search for REGNO. If found, abort if it is not wider than word_mode. */
2578 verify_wide_reg_1 (px, pregno)
2583 unsigned int regno = *(int *) pregno;
2585 if (GET_CODE (x) == REG && REGNO (x) == regno)
2587 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
2594 /* A subroutine of verify_local_live_at_start. Search through insns
2595 between HEAD and END looking for register REGNO. */
2598 verify_wide_reg (regno, head, end)
2604 if (GET_RTX_CLASS (GET_CODE (head)) == 'i'
2605 && for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no))
2609 head = NEXT_INSN (head);
2612 /* We didn't find the register at all. Something's way screwy. */
2616 /* A subroutine of update_life_info. Verify that there are no untoward
2617 changes in live_at_start during a local update. */
2620 verify_local_live_at_start (new_live_at_start, bb)
2621 regset new_live_at_start;
2624 if (reload_completed)
2626 /* After reload, there are no pseudos, nor subregs of multi-word
2627 registers. The regsets should exactly match. */
2628 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
2635 /* Find the set of changed registers. */
2636 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
2638 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
2640 /* No registers should die. */
2641 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
2643 /* Verify that the now-live register is wider than word_mode. */
2644 verify_wide_reg (i, bb->head, bb->end);
2649 /* Updates life information starting with the basic blocks set in BLOCKS.
2650 If BLOCKS is null, consider it to be the universal set.
2652 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
2653 we are only expecting local modifications to basic blocks. If we find
2654 extra registers live at the beginning of a block, then we either killed
2655 useful data, or we have a broken split that wants data not provided.
2656 If we find registers removed from live_at_start, that means we have
2657 a broken peephole that is killing a register it shouldn't.
2659 ??? This is not true in one situation -- when a pre-reload splitter
2660 generates subregs of a multi-word pseudo, current life analysis will
2661 lose the kill. So we _can_ have a pseudo go live. How irritating.
2663 Including PROP_REG_INFO does not properly refresh regs_ever_live
2664 unless the caller resets it to zero. */
2667 update_life_info (blocks, extent, prop_flags)
2669 enum update_life_extent extent;
2673 regset_head tmp_head;
2676 tmp = INITIALIZE_REG_SET (tmp_head);
2678 /* For a global update, we go through the relaxation process again. */
2679 if (extent != UPDATE_LIFE_LOCAL)
2681 calculate_global_regs_live (blocks, blocks,
2682 prop_flags & PROP_SCAN_DEAD_CODE);
2684 /* If asked, remove notes from the blocks we'll update. */
2685 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
2686 count_or_remove_death_notes (blocks, 1);
2691 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
2693 basic_block bb = BASIC_BLOCK (i);
2695 COPY_REG_SET (tmp, bb->global_live_at_end);
2696 propagate_block (bb, tmp, (regset) NULL, prop_flags);
2698 if (extent == UPDATE_LIFE_LOCAL)
2699 verify_local_live_at_start (tmp, bb);
2704 for (i = n_basic_blocks - 1; i >= 0; --i)
2706 basic_block bb = BASIC_BLOCK (i);
2708 COPY_REG_SET (tmp, bb->global_live_at_end);
2709 propagate_block (bb, tmp, (regset) NULL, prop_flags);
2711 if (extent == UPDATE_LIFE_LOCAL)
2712 verify_local_live_at_start (tmp, bb);
2718 if (prop_flags & PROP_REG_INFO)
2720 /* The only pseudos that are live at the beginning of the function
2721 are those that were not set anywhere in the function. local-alloc
2722 doesn't know how to handle these correctly, so mark them as not
2723 local to any one basic block. */
2724 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
2725 FIRST_PSEUDO_REGISTER, i,
2726 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
2728 /* We have a problem with any pseudoreg that lives across the setjmp.
2729 ANSI says that if a user variable does not change in value between
2730 the setjmp and the longjmp, then the longjmp preserves it. This
2731 includes longjmp from a place where the pseudo appears dead.
2732 (In principle, the value still exists if it is in scope.)
2733 If the pseudo goes in a hard reg, some other value may occupy
2734 that hard reg where this pseudo is dead, thus clobbering the pseudo.
2735 Conclusion: such a pseudo must not go in a hard reg. */
2736 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
2737 FIRST_PSEUDO_REGISTER, i,
2739 if (regno_reg_rtx[i] != 0)
2741 REG_LIVE_LENGTH (i) = -1;
2742 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
2748 /* Free the variables allocated by find_basic_blocks.
2750 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
2753 free_basic_block_vars (keep_head_end_p)
2754 int keep_head_end_p;
2756 if (basic_block_for_insn)
2758 VARRAY_FREE (basic_block_for_insn);
2759 basic_block_for_insn = NULL;
2762 if (! keep_head_end_p)
2765 VARRAY_FREE (basic_block_info);
2768 ENTRY_BLOCK_PTR->aux = NULL;
2769 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
2770 EXIT_BLOCK_PTR->aux = NULL;
2771 EXIT_BLOCK_PTR->global_live_at_start = NULL;
2775 /* Return nonzero if the destination of SET equals the source. */
2780 rtx src = SET_SRC (set);
2781 rtx dst = SET_DEST (set);
2783 if (GET_CODE (src) == SUBREG && GET_CODE (dst) == SUBREG)
2785 if (SUBREG_WORD (src) != SUBREG_WORD (dst))
2787 src = SUBREG_REG (src);
2788 dst = SUBREG_REG (dst);
2791 return (GET_CODE (src) == REG && GET_CODE (dst) == REG
2792 && REGNO (src) == REGNO (dst));
2795 /* Return nonzero if an insn consists only of SETs, each of which only sets a
2801 rtx pat = PATTERN (insn);
2803 /* Insns carrying these notes are useful later on. */
2804 if (find_reg_note (insn, REG_EQUAL, NULL_RTX))
2807 if (GET_CODE (pat) == SET && set_noop_p (pat))
2810 if (GET_CODE (pat) == PARALLEL)
2813 /* If nothing but SETs of registers to themselves,
2814 this insn can also be deleted. */
2815 for (i = 0; i < XVECLEN (pat, 0); i++)
2817 rtx tem = XVECEXP (pat, 0, i);
2819 if (GET_CODE (tem) == USE
2820 || GET_CODE (tem) == CLOBBER)
2823 if (GET_CODE (tem) != SET || ! set_noop_p (tem))
2832 /* Delete any insns that copy a register to itself. */
2835 delete_noop_moves (f)
2839 for (insn = f; insn; insn = NEXT_INSN (insn))
2841 if (GET_CODE (insn) == INSN && noop_move_p (insn))
2843 PUT_CODE (insn, NOTE);
2844 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
2845 NOTE_SOURCE_FILE (insn) = 0;
2850 /* Determine if the stack pointer is constant over the life of the function.
2851 Only useful before prologues have been emitted. */
2854 notice_stack_pointer_modification_1 (x, pat, data)
2856 rtx pat ATTRIBUTE_UNUSED;
2857 void *data ATTRIBUTE_UNUSED;
2859 if (x == stack_pointer_rtx
2860 /* The stack pointer is only modified indirectly as the result
2861 of a push until later in flow. See the comments in rtl.texi
2862 regarding Embedded Side-Effects on Addresses. */
2863 || (GET_CODE (x) == MEM
2864 && (GET_CODE (XEXP (x, 0)) == PRE_DEC
2865 || GET_CODE (XEXP (x, 0)) == PRE_INC
2866 || GET_CODE (XEXP (x, 0)) == POST_DEC
2867 || GET_CODE (XEXP (x, 0)) == POST_INC)
2868 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
2869 current_function_sp_is_unchanging = 0;
2873 notice_stack_pointer_modification (f)
2878 /* Assume that the stack pointer is unchanging if alloca hasn't
2880 current_function_sp_is_unchanging = !current_function_calls_alloca;
2881 if (! current_function_sp_is_unchanging)
2884 for (insn = f; insn; insn = NEXT_INSN (insn))
2886 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
2888 /* Check if insn modifies the stack pointer. */
2889 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
2891 if (! current_function_sp_is_unchanging)
2897 /* Mark a register in SET. Hard registers in large modes get all
2898 of their component registers set as well. */
2900 mark_reg (reg, xset)
2904 regset set = (regset) xset;
2905 int regno = REGNO (reg);
2907 if (GET_MODE (reg) == BLKmode)
2910 SET_REGNO_REG_SET (set, regno);
2911 if (regno < FIRST_PSEUDO_REGISTER)
2913 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
2915 SET_REGNO_REG_SET (set, regno + n);
2919 /* Mark those regs which are needed at the end of the function as live
2920 at the end of the last basic block. */
2922 mark_regs_live_at_end (set)
2927 /* If exiting needs the right stack value, consider the stack pointer
2928 live at the end of the function. */
2929 if ((HAVE_epilogue && reload_completed)
2930 || ! EXIT_IGNORE_STACK
2931 || (! FRAME_POINTER_REQUIRED
2932 && ! current_function_calls_alloca
2933 && flag_omit_frame_pointer)
2934 || current_function_sp_is_unchanging)
2936 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
2939 /* Mark the frame pointer if needed at the end of the function. If
2940 we end up eliminating it, it will be removed from the live list
2941 of each basic block by reload. */
2943 if (! reload_completed || frame_pointer_needed)
2945 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
2946 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2947 /* If they are different, also mark the hard frame pointer as live */
2948 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
2952 #ifdef PIC_OFFSET_TABLE_REGNUM
2953 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
2954 /* Many architectures have a GP register even without flag_pic.
2955 Assume the pic register is not in use, or will be handled by
2956 other means, if it is not fixed. */
2957 if (fixed_regs[PIC_OFFSET_TABLE_REGNUM])
2958 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
2962 /* Mark all global registers, and all registers used by the epilogue
2963 as being live at the end of the function since they may be
2964 referenced by our caller. */
2965 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
2967 #ifdef EPILOGUE_USES
2968 || EPILOGUE_USES (i)
2971 SET_REGNO_REG_SET (set, i);
2973 /* Mark all call-saved registers that we actaully used. */
2974 if (HAVE_epilogue && reload_completed)
2976 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
2977 if (! call_used_regs[i] && regs_ever_live[i])
2978 SET_REGNO_REG_SET (set, i);
2981 /* Mark function return value. */
2982 diddle_return_value (mark_reg, set);
2985 /* Callback function for for_each_successor_phi. DATA is a regset.
2986 Sets the SRC_REGNO, the regno of the phi alternative for phi node
2987 INSN, in the regset. */
2990 set_phi_alternative_reg (insn, dest_regno, src_regno, data)
2991 rtx insn ATTRIBUTE_UNUSED;
2992 int dest_regno ATTRIBUTE_UNUSED;
2996 regset live = (regset) data;
2997 SET_REGNO_REG_SET (live, src_regno);
3001 /* Propagate global life info around the graph of basic blocks. Begin
3002 considering blocks with their corresponding bit set in BLOCKS_IN.
3003 If BLOCKS_IN is null, consider it the universal set.
3005 BLOCKS_OUT is set for every block that was changed. */
3008 calculate_global_regs_live (blocks_in, blocks_out, flags)
3009 sbitmap blocks_in, blocks_out;
3012 basic_block *queue, *qhead, *qtail, *qend;
3013 regset tmp, new_live_at_end;
3014 regset_head tmp_head;
3015 regset_head new_live_at_end_head;
3018 tmp = INITIALIZE_REG_SET (tmp_head);
3019 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
3021 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
3022 because the `head == tail' style test for an empty queue doesn't
3023 work with a full queue. */
3024 queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
3026 qhead = qend = queue + n_basic_blocks + 2;
3028 /* Clear out the garbage that might be hanging out in bb->aux. */
3029 for (i = n_basic_blocks - 1; i >= 0; --i)
3030 BASIC_BLOCK (i)->aux = NULL;
3032 /* Queue the blocks set in the initial mask. Do this in reverse block
3033 number order so that we are more likely for the first round to do
3034 useful work. We use AUX non-null to flag that the block is queued. */
3037 EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
3039 basic_block bb = BASIC_BLOCK (i);
3046 for (i = 0; i < n_basic_blocks; ++i)
3048 basic_block bb = BASIC_BLOCK (i);
3055 sbitmap_zero (blocks_out);
3057 while (qhead != qtail)
3059 int rescan, changed;
3068 /* Begin by propogating live_at_start from the successor blocks. */
3069 CLEAR_REG_SET (new_live_at_end);
3070 for (e = bb->succ; e ; e = e->succ_next)
3072 basic_block sb = e->dest;
3073 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
3076 /* Force the stack pointer to be live -- which might not already be
3077 the case for blocks within infinite loops. */
3078 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
3080 /* Regs used in phi nodes are not included in
3081 global_live_at_start, since they are live only along a
3082 particular edge. Set those regs that are live because of a
3083 phi node alternative corresponding to this particular block. */
3085 for_each_successor_phi (bb, &set_phi_alternative_reg,
3088 if (bb == ENTRY_BLOCK_PTR)
3090 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3094 /* On our first pass through this block, we'll go ahead and continue.
3095 Recognize first pass by local_set NULL. On subsequent passes, we
3096 get to skip out early if live_at_end wouldn't have changed. */
3098 if (bb->local_set == NULL)
3100 bb->local_set = OBSTACK_ALLOC_REG_SET (function_obstack);
3105 /* If any bits were removed from live_at_end, we'll have to
3106 rescan the block. This wouldn't be necessary if we had
3107 precalculated local_live, however with PROP_SCAN_DEAD_CODE
3108 local_live is really dependant on live_at_end. */
3109 CLEAR_REG_SET (tmp);
3110 rescan = bitmap_operation (tmp, bb->global_live_at_end,
3111 new_live_at_end, BITMAP_AND_COMPL);
3115 /* Find the set of changed bits. Take this opportunity
3116 to notice that this set is empty and early out. */
3117 CLEAR_REG_SET (tmp);
3118 changed = bitmap_operation (tmp, bb->global_live_at_end,
3119 new_live_at_end, BITMAP_XOR);
3123 /* If any of the changed bits overlap with local_set,
3124 we'll have to rescan the block. Detect overlap by
3125 the AND with ~local_set turning off bits. */
3126 rescan = bitmap_operation (tmp, tmp, bb->local_set,
3131 /* Let our caller know that BB changed enough to require its
3132 death notes updated. */
3134 SET_BIT (blocks_out, bb->index);
3138 /* Add to live_at_start the set of all registers in
3139 new_live_at_end that aren't in the old live_at_end. */
3141 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
3143 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3145 changed = bitmap_operation (bb->global_live_at_start,
3146 bb->global_live_at_start,
3153 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3155 /* Rescan the block insn by insn to turn (a copy of) live_at_end
3156 into live_at_start. */
3157 propagate_block (bb, new_live_at_end, bb->local_set, flags);
3159 /* If live_at start didn't change, no need to go farther. */
3160 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
3163 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
3166 /* Queue all predecessors of BB so that we may re-examine
3167 their live_at_end. */
3168 for (e = bb->pred; e ; e = e->pred_next)
3170 basic_block pb = e->src;
3171 if (pb->aux == NULL)
3182 FREE_REG_SET (new_live_at_end);
3186 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
3188 basic_block bb = BASIC_BLOCK (i);
3189 FREE_REG_SET (bb->local_set);
3194 for (i = n_basic_blocks - 1; i >= 0; --i)
3196 basic_block bb = BASIC_BLOCK (i);
3197 FREE_REG_SET (bb->local_set);
3204 /* Subroutines of life analysis. */
3206 /* Allocate the permanent data structures that represent the results
3207 of life analysis. Not static since used also for stupid life analysis. */
3210 allocate_bb_life_data ()
3214 for (i = 0; i < n_basic_blocks; i++)
3216 basic_block bb = BASIC_BLOCK (i);
3218 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (function_obstack);
3219 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (function_obstack);
3222 ENTRY_BLOCK_PTR->global_live_at_end
3223 = OBSTACK_ALLOC_REG_SET (function_obstack);
3224 EXIT_BLOCK_PTR->global_live_at_start
3225 = OBSTACK_ALLOC_REG_SET (function_obstack);
3227 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (function_obstack);
3231 allocate_reg_life_data ()
3235 max_regno = max_reg_num ();
3237 /* Recalculate the register space, in case it has grown. Old style
3238 vector oriented regsets would set regset_{size,bytes} here also. */
3239 allocate_reg_info (max_regno, FALSE, FALSE);
3241 /* Reset all the data we'll collect in propagate_block and its
3243 for (i = 0; i < max_regno; i++)
3247 REG_N_DEATHS (i) = 0;
3248 REG_N_CALLS_CROSSED (i) = 0;
3249 REG_LIVE_LENGTH (i) = 0;
3250 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
3254 /* Delete dead instructions for propagate_block. */
3257 propagate_block_delete_insn (bb, insn)
3261 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
3263 /* If the insn referred to a label, and that label was attached to
3264 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
3265 pretty much mandatory to delete it, because the ADDR_VEC may be
3266 referencing labels that no longer exist. */
3270 rtx label = XEXP (inote, 0);
3273 if (LABEL_NUSES (label) == 1
3274 && (next = next_nonnote_insn (label)) != NULL
3275 && GET_CODE (next) == JUMP_INSN
3276 && (GET_CODE (PATTERN (next)) == ADDR_VEC
3277 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
3279 rtx pat = PATTERN (next);
3280 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
3281 int len = XVECLEN (pat, diff_vec_p);
3284 for (i = 0; i < len; i++)
3285 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
3287 flow_delete_insn (next);
3291 if (bb->end == insn)
3292 bb->end = PREV_INSN (insn);
3293 flow_delete_insn (insn);
3296 /* Delete dead libcalls for propagate_block. Return the insn
3297 before the libcall. */
3300 propagate_block_delete_libcall (bb, insn, note)
3304 rtx first = XEXP (note, 0);
3305 rtx before = PREV_INSN (first);
3307 if (insn == bb->end)
3310 flow_delete_insn_chain (first, insn);
3314 /* Update the life-status of regs for one insn. Return the previous insn. */
3317 propagate_one_insn (pbi, insn)
3318 struct propagate_block_info *pbi;
3321 rtx prev = PREV_INSN (insn);
3322 int flags = pbi->flags;
3323 int insn_is_dead = 0;
3324 int libcall_is_dead = 0;
3328 if (! INSN_P (insn))
3331 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
3332 if (flags & PROP_SCAN_DEAD_CODE)
3334 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0,
3336 libcall_is_dead = (insn_is_dead && note != 0
3337 && libcall_dead_p (pbi, PATTERN (insn),
3341 /* We almost certainly don't want to delete prologue or epilogue
3342 instructions. Warn about probable compiler losage. */
3345 && (((HAVE_epilogue || HAVE_prologue)
3346 && prologue_epilogue_contains (insn))
3347 || (HAVE_sibcall_epilogue
3348 && sibcall_epilogue_contains (insn))))
3350 if (flags & PROP_KILL_DEAD_CODE)
3352 warning ("ICE: would have deleted prologue/epilogue insn");
3353 if (!inhibit_warnings)
3356 libcall_is_dead = insn_is_dead = 0;
3359 /* If an instruction consists of just dead store(s) on final pass,
3361 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
3363 /* Record sets. Do this even for dead instructions, since they
3364 would have killed the values if they hadn't been deleted. */
3365 mark_set_regs (pbi, PATTERN (insn), insn);
3367 /* CC0 is now known to be dead. Either this insn used it,
3368 in which case it doesn't anymore, or clobbered it,
3369 so the next insn can't use it. */
3372 if (libcall_is_dead)
3374 prev = propagate_block_delete_libcall (pbi->bb, insn, note);
3375 insn = NEXT_INSN (prev);
3378 propagate_block_delete_insn (pbi->bb, insn);
3383 /* See if this is an increment or decrement that can be merged into
3384 a following memory address. */
3387 register rtx x = single_set (insn);
3389 /* Does this instruction increment or decrement a register? */
3390 if (!reload_completed
3391 && (flags & PROP_AUTOINC)
3393 && GET_CODE (SET_DEST (x)) == REG
3394 && (GET_CODE (SET_SRC (x)) == PLUS
3395 || GET_CODE (SET_SRC (x)) == MINUS)
3396 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
3397 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
3398 /* Ok, look for a following memory ref we can combine with.
3399 If one is found, change the memory ref to a PRE_INC
3400 or PRE_DEC, cancel this insn, and return 1.
3401 Return 0 if nothing has been done. */
3402 && try_pre_increment_1 (pbi, insn))
3405 #endif /* AUTO_INC_DEC */
3407 CLEAR_REG_SET (pbi->new_set);
3409 /* If this is not the final pass, and this insn is copying the value of
3410 a library call and it's dead, don't scan the insns that perform the
3411 library call, so that the call's arguments are not marked live. */
3412 if (libcall_is_dead)
3414 /* Record the death of the dest reg. */
3415 mark_set_regs (pbi, PATTERN (insn), insn);
3417 insn = XEXP (note, 0);
3418 return PREV_INSN (insn);
3420 else if (GET_CODE (PATTERN (insn)) == SET
3421 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
3422 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
3423 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
3424 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
3425 /* We have an insn to pop a constant amount off the stack.
3426 (Such insns use PLUS regardless of the direction of the stack,
3427 and any insn to adjust the stack by a constant is always a pop.)
3428 These insns, if not dead stores, have no effect on life. */
3432 /* Any regs live at the time of a call instruction must not go
3433 in a register clobbered by calls. Find all regs now live and
3434 record this for them. */
3436 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
3437 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
3438 { REG_N_CALLS_CROSSED (i)++; });
3440 /* Record sets. Do this even for dead instructions, since they
3441 would have killed the values if they hadn't been deleted. */
3442 mark_set_regs (pbi, PATTERN (insn), insn);
3444 if (GET_CODE (insn) == CALL_INSN)
3450 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
3451 cond = COND_EXEC_TEST (PATTERN (insn));
3453 /* Non-constant calls clobber memory. */
3454 if (! CONST_CALL_P (insn))
3455 free_EXPR_LIST_list (&pbi->mem_set_list);
3457 /* There may be extra registers to be clobbered. */
3458 for (note = CALL_INSN_FUNCTION_USAGE (insn);
3460 note = XEXP (note, 1))
3461 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
3462 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
3463 cond, insn, pbi->flags);
3465 /* Calls change all call-used and global registers. */
3466 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3467 if (call_used_regs[i] && ! global_regs[i]
3470 /* We do not want REG_UNUSED notes for these registers. */
3471 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
3473 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
3477 /* If an insn doesn't use CC0, it becomes dead since we assume
3478 that every insn clobbers it. So show it dead here;
3479 mark_used_regs will set it live if it is referenced. */
3484 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
3486 /* Sometimes we may have inserted something before INSN (such as a move)
3487 when we make an auto-inc. So ensure we will scan those insns. */
3489 prev = PREV_INSN (insn);
3492 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
3498 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
3499 cond = COND_EXEC_TEST (PATTERN (insn));
3501 /* Calls use their arguments. */
3502 for (note = CALL_INSN_FUNCTION_USAGE (insn);
3504 note = XEXP (note, 1))
3505 if (GET_CODE (XEXP (note, 0)) == USE)
3506 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
3509 /* The stack ptr is used (honorarily) by a CALL insn. */
3510 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
3512 /* Calls may also reference any of the global registers,
3513 so they are made live. */
3514 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3516 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
3521 /* On final pass, update counts of how many insns in which each reg
3523 if (flags & PROP_REG_INFO)
3524 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
3525 { REG_LIVE_LENGTH (i)++; });
3530 /* Initialize a propagate_block_info struct for public consumption.
3531 Note that the structure itself is opaque to this file, but that
3532 the user can use the regsets provided here. */
3534 struct propagate_block_info *
3535 init_propagate_block_info (bb, live, local_set, flags)
3541 struct propagate_block_info *pbi = xmalloc (sizeof(*pbi));
3544 pbi->reg_live = live;
3545 pbi->mem_set_list = NULL_RTX;
3546 pbi->local_set = local_set;
3550 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
3551 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
3553 pbi->reg_next_use = NULL;
3555 pbi->new_set = BITMAP_XMALLOC ();
3557 #ifdef HAVE_conditional_execution
3558 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
3559 free_reg_cond_life_info);
3560 pbi->reg_cond_reg = BITMAP_XMALLOC ();
3562 /* If this block ends in a conditional branch, for each register live
3563 from one side of the branch and not the other, record the register
3564 as conditionally dead. */
3565 if (GET_CODE (bb->end) == JUMP_INSN
3566 && condjump_p (bb->end)
3567 && ! simplejump_p (bb->end))
3569 regset_head diff_head;
3570 regset diff = INITIALIZE_REG_SET (diff_head);
3571 basic_block bb_true, bb_false;
3572 rtx cond_true, cond_false;
3575 /* Identify the successor blocks. */
3576 bb_false = bb->succ->succ_next->dest;
3577 bb_true = bb->succ->dest;
3578 if (bb->succ->flags & EDGE_FALLTHRU)
3580 basic_block t = bb_false;
3584 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
3587 /* Extract the condition from the branch. */
3588 cond_true = XEXP (SET_SRC (PATTERN (bb->end)), 0);
3589 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
3590 GET_MODE (cond_true), XEXP (cond_true, 0),
3591 XEXP (cond_true, 1));
3592 if (GET_CODE (XEXP (SET_SRC (PATTERN (bb->end)), 1)) == PC)
3595 cond_false = cond_true;
3599 /* Compute which register lead different lives in the successors. */
3600 if (bitmap_operation (diff, bb_true->global_live_at_start,
3601 bb_false->global_live_at_start, BITMAP_XOR))
3603 if (GET_CODE (XEXP (cond_true, 0)) != REG)
3605 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond_true, 0)));
3607 /* For each such register, mark it conditionally dead. */
3608 EXECUTE_IF_SET_IN_REG_SET
3611 struct reg_cond_life_info *rcli;
3614 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
3616 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
3620 rcli->condition = alloc_EXPR_LIST (0, cond, NULL_RTX);
3622 splay_tree_insert (pbi->reg_cond_dead, i,
3623 (splay_tree_value) rcli);
3627 FREE_REG_SET (diff);
3634 /* Release a propagate_block_info struct. */
3637 free_propagate_block_info (pbi)
3638 struct propagate_block_info *pbi;
3640 free_EXPR_LIST_list (&pbi->mem_set_list);
3642 BITMAP_XFREE (pbi->new_set);
3644 #ifdef HAVE_conditional_execution
3645 splay_tree_delete (pbi->reg_cond_dead);
3646 BITMAP_XFREE (pbi->reg_cond_reg);
3649 if (pbi->reg_next_use)
3650 free (pbi->reg_next_use);
3655 /* Compute the registers live at the beginning of a basic block BB from
3656 those live at the end.
3658 When called, REG_LIVE contains those live at the end. On return, it
3659 contains those live at the beginning.
3661 LOCAL_SET, if non-null, will be set with all registers killed by
3662 this basic block. */
3665 propagate_block (bb, live, local_set, flags)
3671 struct propagate_block_info *pbi;
3674 pbi = init_propagate_block_info (bb, live, local_set, flags);
3676 if (flags & PROP_REG_INFO)
3680 /* Process the regs live at the end of the block.
3681 Mark them as not local to any one basic block. */
3682 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
3683 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
3686 /* Scan the block an insn at a time from end to beginning. */
3688 for (insn = bb->end; ; insn = prev)
3690 /* If this is a call to `setjmp' et al, warn if any
3691 non-volatile datum is live. */
3692 if ((flags & PROP_REG_INFO)
3693 && GET_CODE (insn) == NOTE
3694 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
3695 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
3697 prev = propagate_one_insn (pbi, insn);
3699 if (insn == bb->head)
3703 free_propagate_block_info (pbi);
3706 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
3707 (SET expressions whose destinations are registers dead after the insn).
3708 NEEDED is the regset that says which regs are alive after the insn.
3710 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
3712 If X is the entire body of an insn, NOTES contains the reg notes
3713 pertaining to the insn. */
3716 insn_dead_p (pbi, x, call_ok, notes)
3717 struct propagate_block_info *pbi;
3720 rtx notes ATTRIBUTE_UNUSED;
3722 enum rtx_code code = GET_CODE (x);
3725 /* If flow is invoked after reload, we must take existing AUTO_INC
3726 expresions into account. */
3727 if (reload_completed)
3729 for ( ; notes; notes = XEXP (notes, 1))
3731 if (REG_NOTE_KIND (notes) == REG_INC)
3733 int regno = REGNO (XEXP (notes, 0));
3735 /* Don't delete insns to set global regs. */
3736 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
3737 || REGNO_REG_SET_P (pbi->reg_live, regno))
3744 /* If setting something that's a reg or part of one,
3745 see if that register's altered value will be live. */
3749 rtx r = SET_DEST (x);
3752 if (GET_CODE (r) == CC0)
3753 return ! pbi->cc0_live;
3756 /* A SET that is a subroutine call cannot be dead. */
3757 if (GET_CODE (SET_SRC (x)) == CALL)
3763 /* Don't eliminate loads from volatile memory or volatile asms. */
3764 else if (volatile_refs_p (SET_SRC (x)))
3767 if (GET_CODE (r) == MEM)
3771 if (MEM_VOLATILE_P (r))
3774 /* Walk the set of memory locations we are currently tracking
3775 and see if one is an identical match to this memory location.
3776 If so, this memory write is dead (remember, we're walking
3777 backwards from the end of the block to the start. */
3778 temp = pbi->mem_set_list;
3781 if (rtx_equal_p (XEXP (temp, 0), r))
3783 temp = XEXP (temp, 1);
3788 while (GET_CODE (r) == SUBREG
3789 || GET_CODE (r) == STRICT_LOW_PART
3790 || GET_CODE (r) == ZERO_EXTRACT)
3793 if (GET_CODE (r) == REG)
3795 int regno = REGNO (r);
3798 if (REGNO_REG_SET_P (pbi->reg_live, regno))
3801 /* If this is a hard register, verify that subsequent
3802 words are not needed. */
3803 if (regno < FIRST_PSEUDO_REGISTER)
3805 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
3808 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
3812 /* Don't delete insns to set global regs. */
3813 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
3816 /* Make sure insns to set the stack pointer aren't deleted. */
3817 if (regno == STACK_POINTER_REGNUM)
3820 /* Make sure insns to set the frame pointer aren't deleted. */
3821 if (regno == FRAME_POINTER_REGNUM
3822 && (! reload_completed || frame_pointer_needed))
3824 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3825 if (regno == HARD_FRAME_POINTER_REGNUM
3826 && (! reload_completed || frame_pointer_needed))
3830 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3831 /* Make sure insns to set arg pointer are never deleted
3832 (if the arg pointer isn't fixed, there will be a USE
3833 for it, so we can treat it normally). */
3834 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
3838 /* Otherwise, the set is dead. */
3844 /* If performing several activities, insn is dead if each activity
3845 is individually dead. Also, CLOBBERs and USEs can be ignored; a
3846 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
3848 else if (code == PARALLEL)
3850 int i = XVECLEN (x, 0);
3852 for (i--; i >= 0; i--)
3853 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
3854 && GET_CODE (XVECEXP (x, 0, i)) != USE
3855 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
3861 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
3862 is not necessarily true for hard registers. */
3863 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
3864 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
3865 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
3868 /* We do not check other CLOBBER or USE here. An insn consisting of just
3869 a CLOBBER or just a USE should not be deleted. */
3873 /* If X is the pattern of the last insn in a libcall, and assuming X is dead,
3874 return 1 if the entire library call is dead.
3875 This is true if X copies a register (hard or pseudo)
3876 and if the hard return reg of the call insn is dead.
3877 (The caller should have tested the destination of X already for death.)
3879 If this insn doesn't just copy a register, then we don't
3880 have an ordinary libcall. In that case, cse could not have
3881 managed to substitute the source for the dest later on,
3882 so we can assume the libcall is dead.
3884 NEEDED is the bit vector of pseudoregs live before this insn.
3885 NOTE is the REG_RETVAL note of the insn. INSN is the insn itself. */
3888 libcall_dead_p (pbi, x, note, insn)
3889 struct propagate_block_info *pbi;
3894 register RTX_CODE code = GET_CODE (x);
3898 register rtx r = SET_SRC (x);
3899 if (GET_CODE (r) == REG)
3901 rtx call = XEXP (note, 0);
3905 /* Find the call insn. */
3906 while (call != insn && GET_CODE (call) != CALL_INSN)
3907 call = NEXT_INSN (call);
3909 /* If there is none, do nothing special,
3910 since ordinary death handling can understand these insns. */
3914 /* See if the hard reg holding the value is dead.
3915 If this is a PARALLEL, find the call within it. */
3916 call_pat = PATTERN (call);
3917 if (GET_CODE (call_pat) == PARALLEL)
3919 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
3920 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
3921 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
3924 /* This may be a library call that is returning a value
3925 via invisible pointer. Do nothing special, since
3926 ordinary death handling can understand these insns. */
3930 call_pat = XVECEXP (call_pat, 0, i);
3933 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
3939 /* Return 1 if register REGNO was used before it was set, i.e. if it is
3940 live at function entry. Don't count global register variables, variables
3941 in registers that can be used for function arg passing, or variables in
3942 fixed hard registers. */
3945 regno_uninitialized (regno)
3948 if (n_basic_blocks == 0
3949 || (regno < FIRST_PSEUDO_REGISTER
3950 && (global_regs[regno]
3951 || fixed_regs[regno]
3952 || FUNCTION_ARG_REGNO_P (regno))))
3955 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
3958 /* 1 if register REGNO was alive at a place where `setjmp' was called
3959 and was set more than once or is an argument.
3960 Such regs may be clobbered by `longjmp'. */
3963 regno_clobbered_at_setjmp (regno)
3966 if (n_basic_blocks == 0)
3969 return ((REG_N_SETS (regno) > 1
3970 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
3971 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
3974 /* INSN references memory, possibly using autoincrement addressing modes.
3975 Find any entries on the mem_set_list that need to be invalidated due
3976 to an address change. */
3978 invalidate_mems_from_autoinc (pbi, insn)
3979 struct propagate_block_info *pbi;
3982 rtx note = REG_NOTES (insn);
3983 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
3985 if (REG_NOTE_KIND (note) == REG_INC)
3987 rtx temp = pbi->mem_set_list;
3988 rtx prev = NULL_RTX;
3993 next = XEXP (temp, 1);
3994 if (reg_overlap_mentioned_p (XEXP (note, 0), XEXP (temp, 0)))
3996 /* Splice temp out of list. */
3998 XEXP (prev, 1) = next;
4000 pbi->mem_set_list = next;
4001 free_EXPR_LIST_node (temp);
4011 /* Process the registers that are set within X. Their bits are set to
4012 1 in the regset DEAD, because they are dead prior to this insn.
4014 If INSN is nonzero, it is the insn being processed.
4016 FLAGS is the set of operations to perform. */
4019 mark_set_regs (pbi, x, insn)
4020 struct propagate_block_info *pbi;
4023 rtx cond = NULL_RTX;
4027 switch (code = GET_CODE (x))
4031 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
4035 cond = COND_EXEC_TEST (x);
4036 x = COND_EXEC_CODE (x);
4042 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
4044 rtx sub = XVECEXP (x, 0, i);
4045 switch (code = GET_CODE (sub))
4048 if (cond != NULL_RTX)
4051 cond = COND_EXEC_TEST (sub);
4052 sub = COND_EXEC_CODE (sub);
4053 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
4059 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
4074 /* Process a single SET rtx, X. */
4077 mark_set_1 (pbi, code, reg, cond, insn, flags)
4078 struct propagate_block_info *pbi;
4080 rtx reg, cond, insn;
4083 int regno_first = -1, regno_last = -1;
4087 /* Some targets place small structures in registers for
4088 return values of functions. We have to detect this
4089 case specially here to get correct flow information. */
4090 if (GET_CODE (reg) == PARALLEL
4091 && GET_MODE (reg) == BLKmode)
4093 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
4094 mark_set_1 (pbi, code, XVECEXP (reg, 0, i), cond, insn, flags);
4098 /* Modifying just one hardware register of a multi-reg value or just a
4099 byte field of a register does not mean the value from before this insn
4100 is now dead. Of course, if it was dead after it's unused now. */
4102 switch (GET_CODE (reg))
4106 case STRICT_LOW_PART:
4107 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
4109 reg = XEXP (reg, 0);
4110 while (GET_CODE (reg) == SUBREG
4111 || GET_CODE (reg) == ZERO_EXTRACT
4112 || GET_CODE (reg) == SIGN_EXTRACT
4113 || GET_CODE (reg) == STRICT_LOW_PART);
4114 if (GET_CODE (reg) == MEM)
4116 not_dead = REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
4120 regno_last = regno_first = REGNO (reg);
4121 if (regno_first < FIRST_PSEUDO_REGISTER)
4122 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
4126 if (GET_CODE (SUBREG_REG (reg)) == REG)
4128 enum machine_mode outer_mode = GET_MODE (reg);
4129 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
4131 /* Identify the range of registers affected. This is moderately
4132 tricky for hard registers. See alter_subreg. */
4134 regno_last = regno_first = REGNO (SUBREG_REG (reg));
4135 if (regno_first < FIRST_PSEUDO_REGISTER)
4137 #ifdef ALTER_HARD_SUBREG
4138 regno_first = ALTER_HARD_SUBREG (outer_mode, SUBREG_WORD (reg),
4139 inner_mode, regno_first);
4141 regno_first += SUBREG_WORD (reg);
4143 regno_last = (regno_first
4144 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
4146 /* Since we've just adjusted the register number ranges, make
4147 sure REG matches. Otherwise some_was_live will be clear
4148 when it shouldn't have been, and we'll create incorrect
4149 REG_UNUSED notes. */
4150 reg = gen_rtx_REG (outer_mode, regno_first);
4154 /* If the number of words in the subreg is less than the number
4155 of words in the full register, we have a well-defined partial
4156 set. Otherwise the high bits are undefined.
4158 This is only really applicable to pseudos, since we just took
4159 care of multi-word hard registers. */
4160 if (((GET_MODE_SIZE (outer_mode)
4161 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
4162 < ((GET_MODE_SIZE (inner_mode)
4163 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
4164 not_dead = REGNO_REG_SET_P (pbi->reg_live, regno_first);
4166 reg = SUBREG_REG (reg);
4170 reg = SUBREG_REG (reg);
4177 /* If this set is a MEM, then it kills any aliased writes.
4178 If this set is a REG, then it kills any MEMs which use the reg. */
4179 if (flags & PROP_SCAN_DEAD_CODE)
4181 if (GET_CODE (reg) == MEM || GET_CODE (reg) == REG)
4183 rtx temp = pbi->mem_set_list;
4184 rtx prev = NULL_RTX;
4189 next = XEXP (temp, 1);
4190 if ((GET_CODE (reg) == MEM
4191 && output_dependence (XEXP (temp, 0), reg))
4192 || (GET_CODE (reg) == REG
4193 && reg_overlap_mentioned_p (reg, XEXP (temp, 0))))
4195 /* Splice this entry out of the list. */
4197 XEXP (prev, 1) = next;
4199 pbi->mem_set_list = next;
4200 free_EXPR_LIST_node (temp);
4208 /* If the memory reference had embedded side effects (autoincrement
4209 address modes. Then we may need to kill some entries on the
4211 if (insn && GET_CODE (reg) == MEM)
4212 invalidate_mems_from_autoinc (pbi, insn);
4214 if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
4215 /* We do not know the size of a BLKmode store, so we do not track
4216 them for redundant store elimination. */
4217 && GET_MODE (reg) != BLKmode
4218 /* There are no REG_INC notes for SP, so we can't assume we'll see
4219 everything that invalidates it. To be safe, don't eliminate any
4220 stores though SP; none of them should be redundant anyway. */
4221 && ! reg_mentioned_p (stack_pointer_rtx, reg))
4222 pbi->mem_set_list = alloc_EXPR_LIST (0, reg, pbi->mem_set_list);
4225 if (GET_CODE (reg) == REG
4226 && ! (regno_first == FRAME_POINTER_REGNUM
4227 && (! reload_completed || frame_pointer_needed))
4228 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4229 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
4230 && (! reload_completed || frame_pointer_needed))
4232 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4233 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
4237 int some_was_live = 0, some_was_dead = 0;
4239 for (i = regno_first; i <= regno_last; ++i)
4241 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
4243 SET_REGNO_REG_SET (pbi->local_set, i);
4244 if (code != CLOBBER)
4245 SET_REGNO_REG_SET (pbi->new_set, i);
4247 some_was_live |= needed_regno;
4248 some_was_dead |= ! needed_regno;
4251 #ifdef HAVE_conditional_execution
4252 /* Consider conditional death in deciding that the register needs
4255 /* The stack pointer is never dead. Well, not strictly true,
4256 but it's very difficult to tell from here. Hopefully
4257 combine_stack_adjustments will fix up the most egregious
4259 && regno_first != STACK_POINTER_REGNUM)
4261 for (i = regno_first; i <= regno_last; ++i)
4262 if (! mark_regno_cond_dead (pbi, i, cond))
4267 /* Additional data to record if this is the final pass. */
4268 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
4269 | PROP_DEATH_NOTES | PROP_AUTOINC))
4272 register int blocknum = pbi->bb->index;
4275 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4277 y = pbi->reg_next_use[regno_first];
4279 /* The next use is no longer next, since a store intervenes. */
4280 for (i = regno_first; i <= regno_last; ++i)
4281 pbi->reg_next_use[i] = 0;
4284 if (flags & PROP_REG_INFO)
4286 for (i = regno_first; i <= regno_last; ++i)
4288 /* Count (weighted) references, stores, etc. This counts a
4289 register twice if it is modified, but that is correct. */
4290 REG_N_SETS (i) += 1;
4291 REG_N_REFS (i) += (optimize_size ? 1
4292 : pbi->bb->loop_depth + 1);
4294 /* The insns where a reg is live are normally counted
4295 elsewhere, but we want the count to include the insn
4296 where the reg is set, and the normal counting mechanism
4297 would not count it. */
4298 REG_LIVE_LENGTH (i) += 1;
4301 /* If this is a hard reg, record this function uses the reg. */
4302 if (regno_first < FIRST_PSEUDO_REGISTER)
4304 for (i = regno_first; i <= regno_last; i++)
4305 regs_ever_live[i] = 1;
4309 /* Keep track of which basic blocks each reg appears in. */
4310 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
4311 REG_BASIC_BLOCK (regno_first) = blocknum;
4312 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
4313 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
4317 if (! some_was_dead)
4319 if (flags & PROP_LOG_LINKS)
4321 /* Make a logical link from the next following insn
4322 that uses this register, back to this insn.
4323 The following insns have already been processed.
4325 We don't build a LOG_LINK for hard registers containing
4326 in ASM_OPERANDs. If these registers get replaced,
4327 we might wind up changing the semantics of the insn,
4328 even if reload can make what appear to be valid
4329 assignments later. */
4330 if (y && (BLOCK_NUM (y) == blocknum)
4331 && (regno_first >= FIRST_PSEUDO_REGISTER
4332 || asm_noperands (PATTERN (y)) < 0))
4333 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
4338 else if (! some_was_live)
4340 if (flags & PROP_REG_INFO)
4341 REG_N_DEATHS (regno_first) += 1;
4343 if (flags & PROP_DEATH_NOTES)
4345 /* Note that dead stores have already been deleted
4346 when possible. If we get here, we have found a
4347 dead store that cannot be eliminated (because the
4348 same insn does something useful). Indicate this
4349 by marking the reg being set as dying here. */
4351 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
4356 if (flags & PROP_DEATH_NOTES)
4358 /* This is a case where we have a multi-word hard register
4359 and some, but not all, of the words of the register are
4360 needed in subsequent insns. Write REG_UNUSED notes
4361 for those parts that were not needed. This case should
4364 for (i = regno_first; i <= regno_last; ++i)
4365 if (! REGNO_REG_SET_P (pbi->reg_live, i))
4367 = alloc_EXPR_LIST (REG_UNUSED,
4368 gen_rtx_REG (reg_raw_mode[i], i),
4374 /* Mark the register as being dead. */
4377 /* The stack pointer is never dead. Well, not strictly true,
4378 but it's very difficult to tell from here. Hopefully
4379 combine_stack_adjustments will fix up the most egregious
4381 && regno_first != STACK_POINTER_REGNUM)
4383 for (i = regno_first; i <= regno_last; ++i)
4384 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
4387 else if (GET_CODE (reg) == REG)
4389 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4390 pbi->reg_next_use[regno_first] = 0;
4393 /* If this is the last pass and this is a SCRATCH, show it will be dying
4394 here and count it. */
4395 else if (GET_CODE (reg) == SCRATCH)
4397 if (flags & PROP_DEATH_NOTES)
4399 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
4403 #ifdef HAVE_conditional_execution
4404 /* Mark REGNO conditionally dead. Return true if the register is
4405 now unconditionally dead. */
4408 mark_regno_cond_dead (pbi, regno, cond)
4409 struct propagate_block_info *pbi;
4413 /* If this is a store to a predicate register, the value of the
4414 predicate is changing, we don't know that the predicate as seen
4415 before is the same as that seen after. Flush all dependant
4416 conditions from reg_cond_dead. This will make all such
4417 conditionally live registers unconditionally live. */
4418 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
4419 flush_reg_cond_reg (pbi, regno);
4421 /* If this is an unconditional store, remove any conditional
4422 life that may have existed. */
4423 if (cond == NULL_RTX)
4424 splay_tree_remove (pbi->reg_cond_dead, regno);
4427 splay_tree_node node;
4428 struct reg_cond_life_info *rcli;
4431 /* Otherwise this is a conditional set. Record that fact.
4432 It may have been conditionally used, or there may be a
4433 subsequent set with a complimentary condition. */
4435 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
4438 /* The register was unconditionally live previously.
4439 Record the current condition as the condition under
4440 which it is dead. */
4441 rcli = (struct reg_cond_life_info *)
4442 xmalloc (sizeof (*rcli));
4443 rcli->condition = alloc_EXPR_LIST (0, cond, NULL_RTX);
4444 splay_tree_insert (pbi->reg_cond_dead, regno,
4445 (splay_tree_value) rcli);
4447 SET_REGNO_REG_SET (pbi->reg_cond_reg,
4448 REGNO (XEXP (cond, 0)));
4450 /* Not unconditionaly dead. */
4455 /* The register was conditionally live previously.
4456 Add the new condition to the old. */
4457 rcli = (struct reg_cond_life_info *) node->value;
4458 ncond = rcli->condition;
4459 ncond = ior_reg_cond (ncond, cond);
4461 /* If the register is now unconditionally dead,
4462 remove the entry in the splay_tree. */
4463 if (ncond == const1_rtx)
4464 splay_tree_remove (pbi->reg_cond_dead, regno);
4467 rcli->condition = ncond;
4469 SET_REGNO_REG_SET (pbi->reg_cond_reg,
4470 REGNO (XEXP (cond, 0)));
4472 /* Not unconditionaly dead. */
4481 /* Called from splay_tree_delete for pbi->reg_cond_life. */
4484 free_reg_cond_life_info (value)
4485 splay_tree_value value;
4487 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
4488 free_EXPR_LIST_list (&rcli->condition);
4492 /* Helper function for flush_reg_cond_reg. */
4495 flush_reg_cond_reg_1 (node, data)
4496 splay_tree_node node;
4499 struct reg_cond_life_info *rcli;
4500 int *xdata = (int *) data;
4501 unsigned int regno = xdata[0];
4504 /* Don't need to search if last flushed value was farther on in
4505 the in-order traversal. */
4506 if (xdata[1] >= (int) node->key)
4509 /* Splice out portions of the expression that refer to regno. */
4510 rcli = (struct reg_cond_life_info *) node->value;
4511 c = *(prev = &rcli->condition);
4514 if (regno == REGNO (XEXP (XEXP (c, 0), 0)))
4516 rtx next = XEXP (c, 1);
4517 free_EXPR_LIST_node (c);
4521 c = *(prev = &XEXP (c, 1));
4524 /* If the entire condition is now NULL, signal the node to be removed. */
4525 if (! rcli->condition)
4527 xdata[1] = node->key;
4534 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
4537 flush_reg_cond_reg (pbi, regno)
4538 struct propagate_block_info *pbi;
4545 while (splay_tree_foreach (pbi->reg_cond_dead,
4546 flush_reg_cond_reg_1, pair) == -1)
4547 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
4549 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
4552 /* Logical arithmetic on predicate conditions. IOR, NOT and NAND.
4553 We actually use EXPR_LIST to chain the sub-expressions together
4554 instead of IOR because it's easier to manipulate and we have
4555 the lists.c functions to reuse nodes.
4557 Return a new rtl expression as appropriate. */
4560 ior_reg_cond (old, x)
4563 enum rtx_code x_code;
4567 /* We expect these conditions to be of the form (eq reg 0). */
4568 x_code = GET_CODE (x);
4569 if (GET_RTX_CLASS (x_code) != '<'
4570 || GET_CODE (x_reg = XEXP (x, 0)) != REG
4571 || XEXP (x, 1) != const0_rtx)
4574 /* Search the expression for an existing sub-expression of X_REG. */
4575 for (c = old; c ; c = XEXP (c, 1))
4577 rtx y = XEXP (c, 0);
4578 if (REGNO (XEXP (y, 0)) == REGNO (x_reg))
4580 /* If we find X already present in OLD, we need do nothing. */
4581 if (GET_CODE (y) == x_code)
4584 /* If we find X being a compliment of a condition in OLD,
4585 then the entire condition is true. */
4586 if (GET_CODE (y) == reverse_condition (x_code))
4591 /* Otherwise just add to the chain. */
4592 return alloc_EXPR_LIST (0, x, old);
4599 enum rtx_code x_code;
4602 /* We expect these conditions to be of the form (eq reg 0). */
4603 x_code = GET_CODE (x);
4604 if (GET_RTX_CLASS (x_code) != '<'
4605 || GET_CODE (x_reg = XEXP (x, 0)) != REG
4606 || XEXP (x, 1) != const0_rtx)
4609 return alloc_EXPR_LIST (0, gen_rtx_fmt_ee (reverse_condition (x_code),
4610 VOIDmode, x_reg, const0_rtx),
4615 nand_reg_cond (old, x)
4618 enum rtx_code x_code;
4622 /* We expect these conditions to be of the form (eq reg 0). */
4623 x_code = GET_CODE (x);
4624 if (GET_RTX_CLASS (x_code) != '<'
4625 || GET_CODE (x_reg = XEXP (x, 0)) != REG
4626 || XEXP (x, 1) != const0_rtx)
4629 /* Search the expression for an existing sub-expression of X_REG. */
4631 for (c = *(prev = &old); c ; c = *(prev = &XEXP (c, 1)))
4633 rtx y = XEXP (c, 0);
4634 if (REGNO (XEXP (y, 0)) == REGNO (x_reg))
4636 /* If we find X already present in OLD, then we need to
4638 if (GET_CODE (y) == x_code)
4640 *prev = XEXP (c, 1);
4641 free_EXPR_LIST_node (c);
4642 return old ? old : const0_rtx;
4645 /* If we find X being a compliment of a condition in OLD,
4646 then we need do nothing. */
4647 if (GET_CODE (y) == reverse_condition (x_code))
4652 /* Otherwise, by implication, the register in question is now live for
4653 the inverse of the condition X. */
4654 return alloc_EXPR_LIST (0, gen_rtx_fmt_ee (reverse_condition (x_code),
4655 VOIDmode, x_reg, const0_rtx),
4658 #endif /* HAVE_conditional_execution */
4662 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
4666 find_auto_inc (pbi, x, insn)
4667 struct propagate_block_info *pbi;
4671 rtx addr = XEXP (x, 0);
4672 HOST_WIDE_INT offset = 0;
4675 /* Here we detect use of an index register which might be good for
4676 postincrement, postdecrement, preincrement, or predecrement. */
4678 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
4679 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
4681 if (GET_CODE (addr) == REG)
4684 register int size = GET_MODE_SIZE (GET_MODE (x));
4687 int regno = REGNO (addr);
4689 /* Is the next use an increment that might make auto-increment? */
4690 if ((incr = pbi->reg_next_use[regno]) != 0
4691 && (set = single_set (incr)) != 0
4692 && GET_CODE (set) == SET
4693 && BLOCK_NUM (incr) == BLOCK_NUM (insn)
4694 /* Can't add side effects to jumps; if reg is spilled and
4695 reloaded, there's no way to store back the altered value. */
4696 && GET_CODE (insn) != JUMP_INSN
4697 && (y = SET_SRC (set), GET_CODE (y) == PLUS)
4698 && XEXP (y, 0) == addr
4699 && GET_CODE (XEXP (y, 1)) == CONST_INT
4700 && ((HAVE_POST_INCREMENT
4701 && (INTVAL (XEXP (y, 1)) == size && offset == 0))
4702 || (HAVE_POST_DECREMENT
4703 && (INTVAL (XEXP (y, 1)) == - size && offset == 0))
4704 || (HAVE_PRE_INCREMENT
4705 && (INTVAL (XEXP (y, 1)) == size && offset == size))
4706 || (HAVE_PRE_DECREMENT
4707 && (INTVAL (XEXP (y, 1)) == - size && offset == - size)))
4708 /* Make sure this reg appears only once in this insn. */
4709 && (use = find_use_as_address (PATTERN (insn), addr, offset),
4710 use != 0 && use != (rtx) 1))
4712 rtx q = SET_DEST (set);
4713 enum rtx_code inc_code = (INTVAL (XEXP (y, 1)) == size
4714 ? (offset ? PRE_INC : POST_INC)
4715 : (offset ? PRE_DEC : POST_DEC));
4717 if (dead_or_set_p (incr, addr)
4718 /* Mustn't autoinc an eliminable register. */
4719 && (regno >= FIRST_PSEUDO_REGISTER
4720 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
4722 /* This is the simple case. Try to make the auto-inc. If
4723 we can't, we are done. Otherwise, we will do any
4724 needed updates below. */
4725 if (! validate_change (insn, &XEXP (x, 0),
4726 gen_rtx_fmt_e (inc_code, Pmode, addr),
4730 else if (GET_CODE (q) == REG
4731 /* PREV_INSN used here to check the semi-open interval
4733 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
4734 /* We must also check for sets of q as q may be
4735 a call clobbered hard register and there may
4736 be a call between PREV_INSN (insn) and incr. */
4737 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
4739 /* We have *p followed sometime later by q = p+size.
4740 Both p and q must be live afterward,
4741 and q is not used between INSN and its assignment.
4742 Change it to q = p, ...*q..., q = q+size.
4743 Then fall into the usual case. */
4747 emit_move_insn (q, addr);
4748 insns = get_insns ();
4751 if (basic_block_for_insn)
4752 for (temp = insns; temp; temp = NEXT_INSN (temp))
4753 set_block_for_insn (temp, pbi->bb);
4755 /* If we can't make the auto-inc, or can't make the
4756 replacement into Y, exit. There's no point in making
4757 the change below if we can't do the auto-inc and doing
4758 so is not correct in the pre-inc case. */
4760 validate_change (insn, &XEXP (x, 0),
4761 gen_rtx_fmt_e (inc_code, Pmode, q),
4763 validate_change (incr, &XEXP (y, 0), q, 1);
4764 if (! apply_change_group ())
4767 /* We now know we'll be doing this change, so emit the
4768 new insn(s) and do the updates. */
4769 emit_insns_before (insns, insn);
4771 if (pbi->bb->head == insn)
4772 pbi->bb->head = insns;
4774 /* INCR will become a NOTE and INSN won't contain a
4775 use of ADDR. If a use of ADDR was just placed in
4776 the insn before INSN, make that the next use.
4777 Otherwise, invalidate it. */
4778 if (GET_CODE (PREV_INSN (insn)) == INSN
4779 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
4780 && SET_SRC (PATTERN (PREV_INSN (insn))) == addr)
4781 pbi->reg_next_use[regno] = PREV_INSN (insn);
4783 pbi->reg_next_use[regno] = 0;
4788 /* REGNO is now used in INCR which is below INSN, but it
4789 previously wasn't live here. If we don't mark it as
4790 live, we'll put a REG_DEAD note for it on this insn,
4791 which is incorrect. */
4792 SET_REGNO_REG_SET (pbi->reg_live, regno);
4794 /* If there are any calls between INSN and INCR, show
4795 that REGNO now crosses them. */
4796 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
4797 if (GET_CODE (temp) == CALL_INSN)
4798 REG_N_CALLS_CROSSED (regno)++;
4803 /* If we haven't returned, it means we were able to make the
4804 auto-inc, so update the status. First, record that this insn
4805 has an implicit side effect. */
4808 = alloc_EXPR_LIST (REG_INC, addr, REG_NOTES (insn));
4810 /* Modify the old increment-insn to simply copy
4811 the already-incremented value of our register. */
4812 if (! validate_change (incr, &SET_SRC (set), addr, 0))
4815 /* If that makes it a no-op (copying the register into itself) delete
4816 it so it won't appear to be a "use" and a "set" of this
4818 if (SET_DEST (set) == addr)
4820 /* If the original source was dead, it's dead now. */
4821 rtx note = find_reg_note (incr, REG_DEAD, NULL_RTX);
4822 if (note && XEXP (note, 0) != addr)
4823 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
4825 PUT_CODE (incr, NOTE);
4826 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
4827 NOTE_SOURCE_FILE (incr) = 0;
4830 if (regno >= FIRST_PSEUDO_REGISTER)
4832 /* Count an extra reference to the reg. When a reg is
4833 incremented, spilling it is worse, so we want to make
4834 that less likely. */
4835 REG_N_REFS (regno) += pbi->bb->loop_depth + 1;
4837 /* Count the increment as a setting of the register,
4838 even though it isn't a SET in rtl. */
4839 REG_N_SETS (regno)++;
4844 #endif /* AUTO_INC_DEC */
4847 mark_used_reg (pbi, reg, cond, insn)
4848 struct propagate_block_info *pbi;
4850 rtx cond ATTRIBUTE_UNUSED;
4853 int regno = REGNO (reg);
4854 int some_was_live = REGNO_REG_SET_P (pbi->reg_live, regno);
4855 int some_was_dead = ! some_was_live;
4859 /* A hard reg in a wide mode may really be multiple registers.
4860 If so, mark all of them just like the first. */
4861 if (regno < FIRST_PSEUDO_REGISTER)
4863 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
4866 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, regno + n);
4867 some_was_live |= needed_regno;
4868 some_was_dead |= ! needed_regno;
4872 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4874 /* Record where each reg is used, so when the reg is set we know
4875 the next insn that uses it. */
4876 pbi->reg_next_use[regno] = insn;
4879 if (pbi->flags & PROP_REG_INFO)
4881 if (regno < FIRST_PSEUDO_REGISTER)
4883 /* If this is a register we are going to try to eliminate,
4884 don't mark it live here. If we are successful in
4885 eliminating it, it need not be live unless it is used for
4886 pseudos, in which case it will have been set live when it
4887 was allocated to the pseudos. If the register will not
4888 be eliminated, reload will set it live at that point.
4890 Otherwise, record that this function uses this register. */
4891 /* ??? The PPC backend tries to "eliminate" on the pic
4892 register to itself. This should be fixed. In the mean
4893 time, hack around it. */
4895 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno)
4896 && (regno == FRAME_POINTER_REGNUM
4897 || regno == ARG_POINTER_REGNUM)))
4899 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
4901 regs_ever_live[regno + --n] = 1;
4907 /* Keep track of which basic block each reg appears in. */
4909 register int blocknum = pbi->bb->index;
4910 if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN)
4911 REG_BASIC_BLOCK (regno) = blocknum;
4912 else if (REG_BASIC_BLOCK (regno) != blocknum)
4913 REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL;
4915 /* Count (weighted) number of uses of each reg. */
4916 REG_N_REFS (regno) += pbi->bb->loop_depth + 1;
4920 /* Find out if any of the register was set this insn. */
4921 some_not_set = ! REGNO_REG_SET_P (pbi->new_set, regno);
4922 if (regno < FIRST_PSEUDO_REGISTER)
4924 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
4926 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, regno + n);
4929 /* Record and count the insns in which a reg dies. If it is used in
4930 this insn and was dead below the insn then it dies in this insn.
4931 If it was set in this insn, we do not make a REG_DEAD note;
4932 likewise if we already made such a note. */
4933 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
4937 /* Check for the case where the register dying partially
4938 overlaps the register set by this insn. */
4939 if (regno < FIRST_PSEUDO_REGISTER
4940 && HARD_REGNO_NREGS (regno, GET_MODE (reg)) > 1)
4942 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
4944 some_was_live |= REGNO_REG_SET_P (pbi->new_set, regno + n);
4947 /* If none of the words in X is needed, make a REG_DEAD note.
4948 Otherwise, we must make partial REG_DEAD notes. */
4949 if (! some_was_live)
4951 if ((pbi->flags & PROP_DEATH_NOTES)
4952 && ! find_regno_note (insn, REG_DEAD, regno))
4954 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
4956 if (pbi->flags & PROP_REG_INFO)
4957 REG_N_DEATHS (regno)++;
4961 /* Don't make a REG_DEAD note for a part of a register
4962 that is set in the insn. */
4964 n = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)) - 1;
4965 for (; n >= regno; n--)
4966 if (! REGNO_REG_SET_P (pbi->reg_live, n)
4967 && ! dead_or_set_regno_p (insn, n))
4969 = alloc_EXPR_LIST (REG_DEAD,
4970 gen_rtx_REG (reg_raw_mode[n], n),
4975 SET_REGNO_REG_SET (pbi->reg_live, regno);
4976 if (regno < FIRST_PSEUDO_REGISTER)
4978 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
4980 SET_REGNO_REG_SET (pbi->reg_live, regno + n);
4983 #ifdef HAVE_conditional_execution
4984 /* If this is a conditional use, record that fact. If it is later
4985 conditionally set, we'll know to kill the register. */
4986 if (cond != NULL_RTX)
4988 splay_tree_node node;
4989 struct reg_cond_life_info *rcli;
4994 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
4997 /* The register was unconditionally live previously.
4998 No need to do anything. */
5002 /* The register was conditionally live previously.
5003 Subtract the new life cond from the old death cond. */
5004 rcli = (struct reg_cond_life_info *) node->value;
5005 ncond = rcli->condition;
5006 ncond = nand_reg_cond (ncond, cond);
5008 /* If the register is now unconditionally live, remove the
5009 entry in the splay_tree. */
5010 if (ncond == const0_rtx)
5012 rcli->condition = NULL_RTX;
5013 splay_tree_remove (pbi->reg_cond_dead, regno);
5016 rcli->condition = ncond;
5021 /* The register was not previously live at all. Record
5022 the condition under which it is still dead. */
5023 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
5024 rcli->condition = not_reg_cond (cond);
5025 splay_tree_insert (pbi->reg_cond_dead, regno,
5026 (splay_tree_value) rcli);
5032 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
5033 This is done assuming the registers needed from X are those that
5034 have 1-bits in PBI->REG_LIVE.
5036 INSN is the containing instruction. If INSN is dead, this function
5040 mark_used_regs (pbi, x, cond, insn)
5041 struct propagate_block_info *pbi;
5044 register RTX_CODE code;
5046 int flags = pbi->flags;
5049 code = GET_CODE (x);
5069 /* If we are clobbering a MEM, mark any registers inside the address
5071 if (GET_CODE (XEXP (x, 0)) == MEM)
5072 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
5076 /* Don't bother watching stores to mems if this is not the
5077 final pass. We'll not be deleting dead stores this round. */
5078 if (flags & PROP_SCAN_DEAD_CODE)
5080 /* Invalidate the data for the last MEM stored, but only if MEM is
5081 something that can be stored into. */
5082 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
5083 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
5084 ; /* needn't clear the memory set list */
5087 rtx temp = pbi->mem_set_list;
5088 rtx prev = NULL_RTX;
5093 next = XEXP (temp, 1);
5094 if (anti_dependence (XEXP (temp, 0), x))
5096 /* Splice temp out of the list. */
5098 XEXP (prev, 1) = next;
5100 pbi->mem_set_list = next;
5101 free_EXPR_LIST_node (temp);
5109 /* If the memory reference had embedded side effects (autoincrement
5110 address modes. Then we may need to kill some entries on the
5113 invalidate_mems_from_autoinc (pbi, insn);
5117 if (flags & PROP_AUTOINC)
5118 find_auto_inc (pbi, x, insn);
5123 if (GET_CODE (SUBREG_REG (x)) == REG
5124 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
5125 && (GET_MODE_SIZE (GET_MODE (x))
5126 != GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))))
5127 REG_CHANGES_SIZE (REGNO (SUBREG_REG (x))) = 1;
5129 /* While we're here, optimize this case. */
5131 if (GET_CODE (x) != REG)
5136 /* See a register other than being set => mark it as needed. */
5137 mark_used_reg (pbi, x, cond, insn);
5142 register rtx testreg = SET_DEST (x);
5145 /* If storing into MEM, don't show it as being used. But do
5146 show the address as being used. */
5147 if (GET_CODE (testreg) == MEM)
5150 if (flags & PROP_AUTOINC)
5151 find_auto_inc (pbi, testreg, insn);
5153 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
5154 mark_used_regs (pbi, SET_SRC (x), cond, insn);
5158 /* Storing in STRICT_LOW_PART is like storing in a reg
5159 in that this SET might be dead, so ignore it in TESTREG.
5160 but in some other ways it is like using the reg.
5162 Storing in a SUBREG or a bit field is like storing the entire
5163 register in that if the register's value is not used
5164 then this SET is not needed. */
5165 while (GET_CODE (testreg) == STRICT_LOW_PART
5166 || GET_CODE (testreg) == ZERO_EXTRACT
5167 || GET_CODE (testreg) == SIGN_EXTRACT
5168 || GET_CODE (testreg) == SUBREG)
5170 if (GET_CODE (testreg) == SUBREG
5171 && GET_CODE (SUBREG_REG (testreg)) == REG
5172 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
5173 && (GET_MODE_SIZE (GET_MODE (testreg))
5174 != GET_MODE_SIZE (GET_MODE (SUBREG_REG (testreg)))))
5175 REG_CHANGES_SIZE (REGNO (SUBREG_REG (testreg))) = 1;
5177 /* Modifying a single register in an alternate mode
5178 does not use any of the old value. But these other
5179 ways of storing in a register do use the old value. */
5180 if (GET_CODE (testreg) == SUBREG
5181 && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
5186 testreg = XEXP (testreg, 0);
5189 /* If this is a store into a register, recursively scan the
5190 value being stored. */
5192 if ((GET_CODE (testreg) == PARALLEL
5193 && GET_MODE (testreg) == BLKmode)
5194 || (GET_CODE (testreg) == REG
5195 && (regno = REGNO (testreg),
5196 ! (regno == FRAME_POINTER_REGNUM
5197 && (! reload_completed || frame_pointer_needed)))
5198 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
5199 && ! (regno == HARD_FRAME_POINTER_REGNUM
5200 && (! reload_completed || frame_pointer_needed))
5202 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
5203 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
5208 mark_used_regs (pbi, SET_DEST (x), cond, insn);
5209 mark_used_regs (pbi, SET_SRC (x), cond, insn);
5216 case UNSPEC_VOLATILE:
5220 /* Traditional and volatile asm instructions must be considered to use
5221 and clobber all hard registers, all pseudo-registers and all of
5222 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
5224 Consider for instance a volatile asm that changes the fpu rounding
5225 mode. An insn should not be moved across this even if it only uses
5226 pseudo-regs because it might give an incorrectly rounded result.
5228 ?!? Unfortunately, marking all hard registers as live causes massive
5229 problems for the register allocator and marking all pseudos as live
5230 creates mountains of uninitialized variable warnings.
5232 So for now, just clear the memory set list and mark any regs
5233 we can find in ASM_OPERANDS as used. */
5234 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
5235 free_EXPR_LIST_list (&pbi->mem_set_list);
5237 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
5238 We can not just fall through here since then we would be confused
5239 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
5240 traditional asms unlike their normal usage. */
5241 if (code == ASM_OPERANDS)
5245 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
5246 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
5252 if (cond != NULL_RTX)
5255 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
5257 cond = COND_EXEC_TEST (x);
5258 x = COND_EXEC_CODE (x);
5262 /* We _do_not_ want to scan operands of phi nodes. Operands of
5263 a phi function are evaluated only when control reaches this
5264 block along a particular edge. Therefore, regs that appear
5265 as arguments to phi should not be added to the global live at
5273 /* Recursively scan the operands of this expression. */
5276 register const char *fmt = GET_RTX_FORMAT (code);
5279 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5283 /* Tail recursive case: save a function call level. */
5289 mark_used_regs (pbi, XEXP (x, i), cond, insn);
5291 else if (fmt[i] == 'E')
5294 for (j = 0; j < XVECLEN (x, i); j++)
5295 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
5304 try_pre_increment_1 (pbi, insn)
5305 struct propagate_block_info *pbi;
5308 /* Find the next use of this reg. If in same basic block,
5309 make it do pre-increment or pre-decrement if appropriate. */
5310 rtx x = single_set (insn);
5311 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
5312 * INTVAL (XEXP (SET_SRC (x), 1)));
5313 int regno = REGNO (SET_DEST (x));
5314 rtx y = pbi->reg_next_use[regno];
5316 && BLOCK_NUM (y) == BLOCK_NUM (insn)
5317 /* Don't do this if the reg dies, or gets set in y; a standard addressing
5318 mode would be better. */
5319 && ! dead_or_set_p (y, SET_DEST (x))
5320 && try_pre_increment (y, SET_DEST (x), amount))
5322 /* We have found a suitable auto-increment
5323 and already changed insn Y to do it.
5324 So flush this increment-instruction. */
5325 PUT_CODE (insn, NOTE);
5326 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
5327 NOTE_SOURCE_FILE (insn) = 0;
5328 /* Count a reference to this reg for the increment
5329 insn we are deleting. When a reg is incremented.
5330 spilling it is worse, so we want to make that
5332 if (regno >= FIRST_PSEUDO_REGISTER)
5334 REG_N_REFS (regno) += pbi->bb->loop_depth + 1;
5335 REG_N_SETS (regno)++;
5342 /* Try to change INSN so that it does pre-increment or pre-decrement
5343 addressing on register REG in order to add AMOUNT to REG.
5344 AMOUNT is negative for pre-decrement.
5345 Returns 1 if the change could be made.
5346 This checks all about the validity of the result of modifying INSN. */
5349 try_pre_increment (insn, reg, amount)
5351 HOST_WIDE_INT amount;
5355 /* Nonzero if we can try to make a pre-increment or pre-decrement.
5356 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
5358 /* Nonzero if we can try to make a post-increment or post-decrement.
5359 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
5360 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
5361 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
5364 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
5367 /* From the sign of increment, see which possibilities are conceivable
5368 on this target machine. */
5369 if (HAVE_PRE_INCREMENT && amount > 0)
5371 if (HAVE_POST_INCREMENT && amount > 0)
5374 if (HAVE_PRE_DECREMENT && amount < 0)
5376 if (HAVE_POST_DECREMENT && amount < 0)
5379 if (! (pre_ok || post_ok))
5382 /* It is not safe to add a side effect to a jump insn
5383 because if the incremented register is spilled and must be reloaded
5384 there would be no way to store the incremented value back in memory. */
5386 if (GET_CODE (insn) == JUMP_INSN)
5391 use = find_use_as_address (PATTERN (insn), reg, 0);
5392 if (post_ok && (use == 0 || use == (rtx) 1))
5394 use = find_use_as_address (PATTERN (insn), reg, -amount);
5398 if (use == 0 || use == (rtx) 1)
5401 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
5404 /* See if this combination of instruction and addressing mode exists. */
5405 if (! validate_change (insn, &XEXP (use, 0),
5406 gen_rtx_fmt_e (amount > 0
5407 ? (do_post ? POST_INC : PRE_INC)
5408 : (do_post ? POST_DEC : PRE_DEC),
5412 /* Record that this insn now has an implicit side effect on X. */
5413 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
5417 #endif /* AUTO_INC_DEC */
5419 /* Find the place in the rtx X where REG is used as a memory address.
5420 Return the MEM rtx that so uses it.
5421 If PLUSCONST is nonzero, search instead for a memory address equivalent to
5422 (plus REG (const_int PLUSCONST)).
5424 If such an address does not appear, return 0.
5425 If REG appears more than once, or is used other than in such an address,
5429 find_use_as_address (x, reg, plusconst)
5432 HOST_WIDE_INT plusconst;
5434 enum rtx_code code = GET_CODE (x);
5435 const char *fmt = GET_RTX_FORMAT (code);
5437 register rtx value = 0;
5440 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
5443 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
5444 && XEXP (XEXP (x, 0), 0) == reg
5445 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
5446 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
5449 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
5451 /* If REG occurs inside a MEM used in a bit-field reference,
5452 that is unacceptable. */
5453 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
5454 return (rtx) (HOST_WIDE_INT) 1;
5458 return (rtx) (HOST_WIDE_INT) 1;
5460 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5464 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
5468 return (rtx) (HOST_WIDE_INT) 1;
5470 else if (fmt[i] == 'E')
5473 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
5475 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
5479 return (rtx) (HOST_WIDE_INT) 1;
5487 /* Write information about registers and basic blocks into FILE.
5488 This is part of making a debugging dump. */
5491 dump_regset (r, outf)
5498 fputs (" (nil)", outf);
5502 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
5504 fprintf (outf, " %d", i);
5505 if (i < FIRST_PSEUDO_REGISTER)
5506 fprintf (outf, " [%s]",
5515 dump_regset (r, stderr);
5516 putc ('\n', stderr);
5520 dump_flow_info (file)
5524 static const char * const reg_class_names[] = REG_CLASS_NAMES;
5526 fprintf (file, "%d registers.\n", max_regno);
5527 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
5530 enum reg_class class, altclass;
5531 fprintf (file, "\nRegister %d used %d times across %d insns",
5532 i, REG_N_REFS (i), REG_LIVE_LENGTH (i));
5533 if (REG_BASIC_BLOCK (i) >= 0)
5534 fprintf (file, " in block %d", REG_BASIC_BLOCK (i));
5536 fprintf (file, "; set %d time%s", REG_N_SETS (i),
5537 (REG_N_SETS (i) == 1) ? "" : "s");
5538 if (REG_USERVAR_P (regno_reg_rtx[i]))
5539 fprintf (file, "; user var");
5540 if (REG_N_DEATHS (i) != 1)
5541 fprintf (file, "; dies in %d places", REG_N_DEATHS (i));
5542 if (REG_N_CALLS_CROSSED (i) == 1)
5543 fprintf (file, "; crosses 1 call");
5544 else if (REG_N_CALLS_CROSSED (i))
5545 fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i));
5546 if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
5547 fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
5548 class = reg_preferred_class (i);
5549 altclass = reg_alternate_class (i);
5550 if (class != GENERAL_REGS || altclass != ALL_REGS)
5552 if (altclass == ALL_REGS || class == ALL_REGS)
5553 fprintf (file, "; pref %s", reg_class_names[(int) class]);
5554 else if (altclass == NO_REGS)
5555 fprintf (file, "; %s or none", reg_class_names[(int) class]);
5557 fprintf (file, "; pref %s, else %s",
5558 reg_class_names[(int) class],
5559 reg_class_names[(int) altclass]);
5561 if (REGNO_POINTER_FLAG (i))
5562 fprintf (file, "; pointer");
5563 fprintf (file, ".\n");
5566 fprintf (file, "\n%d basic blocks, %d edges.\n", n_basic_blocks, n_edges);
5567 for (i = 0; i < n_basic_blocks; i++)
5569 register basic_block bb = BASIC_BLOCK (i);
5572 fprintf (file, "\nBasic block %d: first insn %d, last %d, loop_depth %d.\n",
5573 i, INSN_UID (bb->head), INSN_UID (bb->end), bb->loop_depth);
5575 fprintf (file, "Predecessors: ");
5576 for (e = bb->pred; e ; e = e->pred_next)
5577 dump_edge_info (file, e, 0);
5579 fprintf (file, "\nSuccessors: ");
5580 for (e = bb->succ; e ; e = e->succ_next)
5581 dump_edge_info (file, e, 1);
5583 fprintf (file, "\nRegisters live at start:");
5584 dump_regset (bb->global_live_at_start, file);
5586 fprintf (file, "\nRegisters live at end:");
5587 dump_regset (bb->global_live_at_end, file);
5598 dump_flow_info (stderr);
5602 dump_edge_info (file, e, do_succ)
5607 basic_block side = (do_succ ? e->dest : e->src);
5609 if (side == ENTRY_BLOCK_PTR)
5610 fputs (" ENTRY", file);
5611 else if (side == EXIT_BLOCK_PTR)
5612 fputs (" EXIT", file);
5614 fprintf (file, " %d", side->index);
5618 static const char * const bitnames[] = {
5619 "fallthru", "crit", "ab", "abcall", "eh", "fake"
5622 int i, flags = e->flags;
5626 for (i = 0; flags; i++)
5627 if (flags & (1 << i))
5633 if (i < (int)(sizeof (bitnames) / sizeof (*bitnames)))
5634 fputs (bitnames[i], file);
5636 fprintf (file, "%d", i);
5644 /* Print out one basic block with live information at start and end. */
5654 fprintf (outf, ";; Basic block %d, loop depth %d",
5655 bb->index, bb->loop_depth);
5656 if (bb->eh_beg != -1 || bb->eh_end != -1)
5657 fprintf (outf, ", eh regions %d/%d", bb->eh_beg, bb->eh_end);
5660 fputs (";; Predecessors: ", outf);
5661 for (e = bb->pred; e ; e = e->pred_next)
5662 dump_edge_info (outf, e, 0);
5665 fputs (";; Registers live at start:", outf);
5666 dump_regset (bb->global_live_at_start, outf);
5669 for (insn = bb->head, last = NEXT_INSN (bb->end);
5671 insn = NEXT_INSN (insn))
5672 print_rtl_single (outf, insn);
5674 fputs (";; Registers live at end:", outf);
5675 dump_regset (bb->global_live_at_end, outf);
5678 fputs (";; Successors: ", outf);
5679 for (e = bb->succ; e; e = e->succ_next)
5680 dump_edge_info (outf, e, 1);
5688 dump_bb (bb, stderr);
5695 dump_bb (BASIC_BLOCK(n), stderr);
5698 /* Like print_rtl, but also print out live information for the start of each
5702 print_rtl_with_bb (outf, rtx_first)
5706 register rtx tmp_rtx;
5709 fprintf (outf, "(nil)\n");
5713 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
5714 int max_uid = get_max_uid ();
5715 basic_block *start = (basic_block *)
5716 xcalloc (max_uid, sizeof (basic_block));
5717 basic_block *end = (basic_block *)
5718 xcalloc (max_uid, sizeof (basic_block));
5719 enum bb_state *in_bb_p = (enum bb_state *)
5720 xcalloc (max_uid, sizeof (enum bb_state));
5722 for (i = n_basic_blocks - 1; i >= 0; i--)
5724 basic_block bb = BASIC_BLOCK (i);
5727 start[INSN_UID (bb->head)] = bb;
5728 end[INSN_UID (bb->end)] = bb;
5729 for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x))
5731 enum bb_state state = IN_MULTIPLE_BB;
5732 if (in_bb_p[INSN_UID(x)] == NOT_IN_BB)
5734 in_bb_p[INSN_UID(x)] = state;
5741 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
5746 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
5748 fprintf (outf, ";; Start of basic block %d, registers live:",
5750 dump_regset (bb->global_live_at_start, outf);
5754 if (in_bb_p[INSN_UID(tmp_rtx)] == NOT_IN_BB
5755 && GET_CODE (tmp_rtx) != NOTE
5756 && GET_CODE (tmp_rtx) != BARRIER)
5757 fprintf (outf, ";; Insn is not within a basic block\n");
5758 else if (in_bb_p[INSN_UID(tmp_rtx)] == IN_MULTIPLE_BB)
5759 fprintf (outf, ";; Insn is in multiple basic blocks\n");
5761 did_output = print_rtl_single (outf, tmp_rtx);
5763 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
5765 fprintf (outf, ";; End of basic block %d, registers live:\n",
5767 dump_regset (bb->global_live_at_end, outf);
5780 if (current_function_epilogue_delay_list != 0)
5782 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
5783 for (tmp_rtx = current_function_epilogue_delay_list; tmp_rtx != 0;
5784 tmp_rtx = XEXP (tmp_rtx, 1))
5785 print_rtl_single (outf, XEXP (tmp_rtx, 0));
5789 /* Compute dominator relationships using new flow graph structures. */
5791 compute_flow_dominators (dominators, post_dominators)
5792 sbitmap *dominators;
5793 sbitmap *post_dominators;
5796 sbitmap *temp_bitmap;
5798 basic_block *worklist, *workend, *qin, *qout;
5801 /* Allocate a worklist array/queue. Entries are only added to the
5802 list if they were not already on the list. So the size is
5803 bounded by the number of basic blocks. */
5804 worklist = (basic_block *) xmalloc (sizeof (basic_block) * n_basic_blocks);
5805 workend = &worklist[n_basic_blocks];
5807 temp_bitmap = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
5808 sbitmap_vector_zero (temp_bitmap, n_basic_blocks);
5812 /* The optimistic setting of dominators requires us to put every
5813 block on the work list initially. */
5814 qin = qout = worklist;
5815 for (bb = 0; bb < n_basic_blocks; bb++)
5817 *qin++ = BASIC_BLOCK (bb);
5818 BASIC_BLOCK (bb)->aux = BASIC_BLOCK (bb);
5820 qlen = n_basic_blocks;
5823 /* We want a maximal solution, so initially assume everything dominates
5825 sbitmap_vector_ones (dominators, n_basic_blocks);
5827 /* Mark successors of the entry block so we can identify them below. */
5828 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
5829 e->dest->aux = ENTRY_BLOCK_PTR;
5831 /* Iterate until the worklist is empty. */
5834 /* Take the first entry off the worklist. */
5835 basic_block b = *qout++;
5836 if (qout >= workend)
5842 /* Compute the intersection of the dominators of all the
5845 If one of the predecessor blocks is the ENTRY block, then the
5846 intersection of the dominators of the predecessor blocks is
5847 defined as the null set. We can identify such blocks by the
5848 special value in the AUX field in the block structure. */
5849 if (b->aux == ENTRY_BLOCK_PTR)
5851 /* Do not clear the aux field for blocks which are
5852 successors of the ENTRY block. That way we we never
5853 add them to the worklist again.
5855 The intersect of dominators of the preds of this block is
5856 defined as the null set. */
5857 sbitmap_zero (temp_bitmap[bb]);
5861 /* Clear the aux field of this block so it can be added to
5862 the worklist again if necessary. */
5864 sbitmap_intersection_of_preds (temp_bitmap[bb], dominators, bb);
5867 /* Make sure each block always dominates itself. */
5868 SET_BIT (temp_bitmap[bb], bb);
5870 /* If the out state of this block changed, then we need to
5871 add the successors of this block to the worklist if they
5872 are not already on the worklist. */
5873 if (sbitmap_a_and_b (dominators[bb], dominators[bb], temp_bitmap[bb]))
5875 for (e = b->succ; e; e = e->succ_next)
5877 if (!e->dest->aux && e->dest != EXIT_BLOCK_PTR)
5891 if (post_dominators)
5893 /* The optimistic setting of dominators requires us to put every
5894 block on the work list initially. */
5895 qin = qout = worklist;
5896 for (bb = 0; bb < n_basic_blocks; bb++)
5898 *qin++ = BASIC_BLOCK (bb);
5899 BASIC_BLOCK (bb)->aux = BASIC_BLOCK (bb);
5901 qlen = n_basic_blocks;
5904 /* We want a maximal solution, so initially assume everything post
5905 dominates everything else. */
5906 sbitmap_vector_ones (post_dominators, n_basic_blocks);
5908 /* Mark predecessors of the exit block so we can identify them below. */
5909 for (e = EXIT_BLOCK_PTR->pred; e; e = e->pred_next)
5910 e->src->aux = EXIT_BLOCK_PTR;
5912 /* Iterate until the worklist is empty. */
5915 /* Take the first entry off the worklist. */
5916 basic_block b = *qout++;
5917 if (qout >= workend)
5923 /* Compute the intersection of the post dominators of all the
5926 If one of the successor blocks is the EXIT block, then the
5927 intersection of the dominators of the successor blocks is
5928 defined as the null set. We can identify such blocks by the
5929 special value in the AUX field in the block structure. */
5930 if (b->aux == EXIT_BLOCK_PTR)
5932 /* Do not clear the aux field for blocks which are
5933 predecessors of the EXIT block. That way we we never
5934 add them to the worklist again.
5936 The intersect of dominators of the succs of this block is
5937 defined as the null set. */
5938 sbitmap_zero (temp_bitmap[bb]);
5942 /* Clear the aux field of this block so it can be added to
5943 the worklist again if necessary. */
5945 sbitmap_intersection_of_succs (temp_bitmap[bb],
5946 post_dominators, bb);
5949 /* Make sure each block always post dominates itself. */
5950 SET_BIT (temp_bitmap[bb], bb);
5952 /* If the out state of this block changed, then we need to
5953 add the successors of this block to the worklist if they
5954 are not already on the worklist. */
5955 if (sbitmap_a_and_b (post_dominators[bb],
5956 post_dominators[bb],
5959 for (e = b->pred; e; e = e->pred_next)
5961 if (!e->src->aux && e->src != ENTRY_BLOCK_PTR)
5979 /* Given DOMINATORS, compute the immediate dominators into IDOM. */
5982 compute_immediate_dominators (idom, dominators)
5984 sbitmap *dominators;
5989 tmp = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
5991 /* Begin with tmp(n) = dom(n) - { n }. */
5992 for (b = n_basic_blocks; --b >= 0; )
5994 sbitmap_copy (tmp[b], dominators[b]);
5995 RESET_BIT (tmp[b], b);
5998 /* Subtract out all of our dominator's dominators. */
5999 for (b = n_basic_blocks; --b >= 0; )
6001 sbitmap tmp_b = tmp[b];
6004 for (s = n_basic_blocks; --s >= 0; )
6005 if (TEST_BIT (tmp_b, s))
6006 sbitmap_difference (tmp_b, tmp_b, tmp[s]);
6009 /* Find the one bit set in the bitmap and put it in the output array. */
6010 for (b = n_basic_blocks; --b >= 0; )
6013 EXECUTE_IF_SET_IN_SBITMAP (tmp[b], 0, t, { idom[b] = t; });
6016 sbitmap_vector_free (tmp);
6019 /* Recompute register set/reference counts immediately prior to register
6022 This avoids problems with set/reference counts changing to/from values
6023 which have special meanings to the register allocators.
6025 Additionally, the reference counts are the primary component used by the
6026 register allocators to prioritize pseudos for allocation to hard regs.
6027 More accurate reference counts generally lead to better register allocation.
6029 F is the first insn to be scanned.
6031 LOOP_STEP denotes how much loop_depth should be incremented per
6032 loop nesting level in order to increase the ref count more for
6033 references in a loop.
6035 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
6036 possibly other information which is used by the register allocators. */
6039 recompute_reg_usage (f, loop_step)
6040 rtx f ATTRIBUTE_UNUSED;
6041 int loop_step ATTRIBUTE_UNUSED;
6043 allocate_reg_life_data ();
6044 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
6047 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
6048 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
6049 of the number of registers that died. */
6052 count_or_remove_death_notes (blocks, kill)
6058 for (i = n_basic_blocks - 1; i >= 0; --i)
6063 if (blocks && ! TEST_BIT (blocks, i))
6066 bb = BASIC_BLOCK (i);
6068 for (insn = bb->head; ; insn = NEXT_INSN (insn))
6070 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
6072 rtx *pprev = ®_NOTES (insn);
6077 switch (REG_NOTE_KIND (link))
6080 if (GET_CODE (XEXP (link, 0)) == REG)
6082 rtx reg = XEXP (link, 0);
6085 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
6088 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
6096 rtx next = XEXP (link, 1);
6097 free_EXPR_LIST_node (link);
6098 *pprev = link = next;
6104 pprev = &XEXP (link, 1);
6111 if (insn == bb->end)
6119 /* Record INSN's block as BB. */
6122 set_block_for_insn (insn, bb)
6126 size_t uid = INSN_UID (insn);
6127 if (uid >= basic_block_for_insn->num_elements)
6131 /* Add one-eighth the size so we don't keep calling xrealloc. */
6132 new_size = uid + (uid + 7) / 8;
6134 VARRAY_GROW (basic_block_for_insn, new_size);
6136 VARRAY_BB (basic_block_for_insn, uid) = bb;
6139 /* Record INSN's block number as BB. */
6140 /* ??? This has got to go. */
6143 set_block_num (insn, bb)
6147 set_block_for_insn (insn, BASIC_BLOCK (bb));
6150 /* Verify the CFG consistency. This function check some CFG invariants and
6151 aborts when something is wrong. Hope that this function will help to
6152 convert many optimization passes to preserve CFG consistent.
6154 Currently it does following checks:
6156 - test head/end pointers
6157 - overlapping of basic blocks
6158 - edge list corectness
6159 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
6160 - tails of basic blocks (ensure that boundary is necesary)
6161 - scans body of the basic block for JUMP_INSN, CODE_LABEL
6162 and NOTE_INSN_BASIC_BLOCK
6163 - check that all insns are in the basic blocks
6164 (except the switch handling code, barriers and notes)
6165 - check that all returns are followed by barriers
6167 In future it can be extended check a lot of other stuff as well
6168 (reachability of basic blocks, life information, etc. etc.). */
6173 const int max_uid = get_max_uid ();
6174 const rtx rtx_first = get_insns ();
6175 basic_block *bb_info;
6177 int i, last_bb_num_seen, num_bb_notes, err = 0;
6179 bb_info = (basic_block *) xcalloc (max_uid, sizeof (basic_block));
6181 /* First pass check head/end pointers and set bb_info array used by
6183 for (i = n_basic_blocks - 1; i >= 0; i--)
6185 basic_block bb = BASIC_BLOCK (i);
6187 /* Check the head pointer and make sure that it is pointing into
6189 for (x = rtx_first; x != NULL_RTX; x = NEXT_INSN (x))
6194 error ("Head insn %d for block %d not found in the insn stream.",
6195 INSN_UID (bb->head), bb->index);
6199 /* Check the end pointer and make sure that it is pointing into
6201 for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x))
6203 if (bb_info[INSN_UID (x)] != NULL)
6205 error ("Insn %d is in multiple basic blocks (%d and %d)",
6206 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
6209 bb_info[INSN_UID (x)] = bb;
6216 error ("End insn %d for block %d not found in the insn stream.",
6217 INSN_UID (bb->end), bb->index);
6222 /* Now check the basic blocks (boundaries etc.) */
6223 for (i = n_basic_blocks - 1; i >= 0; i--)
6225 basic_block bb = BASIC_BLOCK (i);
6226 /* Check corectness of edge lists */
6234 fprintf (stderr, "verify_flow_info: Basic block %d succ edge is corrupted\n",
6236 fprintf (stderr, "Predecessor: ");
6237 dump_edge_info (stderr, e, 0);
6238 fprintf (stderr, "\nSuccessor: ");
6239 dump_edge_info (stderr, e, 1);
6243 if (e->dest != EXIT_BLOCK_PTR)
6245 edge e2 = e->dest->pred;
6246 while (e2 && e2 != e)
6250 error ("Basic block %i edge lists are corrupted", bb->index);
6262 error ("Basic block %d pred edge is corrupted", bb->index);
6263 fputs ("Predecessor: ", stderr);
6264 dump_edge_info (stderr, e, 0);
6265 fputs ("\nSuccessor: ", stderr);
6266 dump_edge_info (stderr, e, 1);
6267 fputc ('\n', stderr);
6270 if (e->src != ENTRY_BLOCK_PTR)
6272 edge e2 = e->src->succ;
6273 while (e2 && e2 != e)
6277 error ("Basic block %i edge lists are corrupted", bb->index);
6284 /* OK pointers are correct. Now check the header of basic
6285 block. It ought to contain optional CODE_LABEL followed
6286 by NOTE_BASIC_BLOCK. */
6288 if (GET_CODE (x) == CODE_LABEL)
6292 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
6298 if (GET_CODE (x) != NOTE
6299 || NOTE_LINE_NUMBER (x) != NOTE_INSN_BASIC_BLOCK
6300 || NOTE_BASIC_BLOCK (x) != bb)
6302 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d\n",
6309 /* Do checks for empty blocks here */
6316 if (GET_CODE (x) == NOTE
6317 && NOTE_LINE_NUMBER (x) == NOTE_INSN_BASIC_BLOCK)
6319 error ("NOTE_INSN_BASIC_BLOCK %d in the middle of basic block %d",
6320 INSN_UID (x), bb->index);
6327 if (GET_CODE (x) == JUMP_INSN
6328 || GET_CODE (x) == CODE_LABEL
6329 || GET_CODE (x) == BARRIER)
6331 error ("In basic block %d:", bb->index);
6332 fatal_insn ("Flow control insn inside a basic block", x);
6340 last_bb_num_seen = -1;
6345 if (GET_CODE (x) == NOTE
6346 && NOTE_LINE_NUMBER (x) == NOTE_INSN_BASIC_BLOCK)
6348 basic_block bb = NOTE_BASIC_BLOCK (x);
6350 if (bb->index != last_bb_num_seen + 1)
6351 fatal ("Basic blocks not numbered consecutively");
6352 last_bb_num_seen = bb->index;
6355 if (!bb_info[INSN_UID (x)])
6357 switch (GET_CODE (x))
6364 /* An addr_vec is placed outside any block block. */
6366 && GET_CODE (NEXT_INSN (x)) == JUMP_INSN
6367 && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
6368 || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
6373 /* But in any case, non-deletable labels can appear anywhere. */
6377 fatal_insn ("Insn outside basic block", x);
6381 if (GET_RTX_CLASS (GET_CODE (x)) == 'i'
6382 && GET_CODE (x) == JUMP_INSN
6383 && returnjump_p (x) && ! condjump_p (x)
6384 && ! (NEXT_INSN (x) && GET_CODE (NEXT_INSN (x)) == BARRIER))
6385 fatal_insn ("Return not followed by barrier", x);
6390 if (num_bb_notes != n_basic_blocks)
6391 fatal ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
6392 num_bb_notes, n_basic_blocks);
6401 /* Functions to access an edge list with a vector representation.
6402 Enough data is kept such that given an index number, the
6403 pred and succ that edge reprsents can be determined, or
6404 given a pred and a succ, it's index number can be returned.
6405 This allows algorithms which comsume a lot of memory to
6406 represent the normally full matrix of edge (pred,succ) with a
6407 single indexed vector, edge (EDGE_INDEX (pred, succ)), with no
6408 wasted space in the client code due to sparse flow graphs. */
6410 /* This functions initializes the edge list. Basically the entire
6411 flowgraph is processed, and all edges are assigned a number,
6412 and the data structure is filed in. */
6416 struct edge_list *elist;
6422 block_count = n_basic_blocks + 2; /* Include the entry and exit blocks. */
6426 /* Determine the number of edges in the flow graph by counting successor
6427 edges on each basic block. */
6428 for (x = 0; x < n_basic_blocks; x++)
6430 basic_block bb = BASIC_BLOCK (x);
6432 for (e = bb->succ; e; e = e->succ_next)
6435 /* Don't forget successors of the entry block. */
6436 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
6439 elist = (struct edge_list *) xmalloc (sizeof (struct edge_list));
6440 elist->num_blocks = block_count;
6441 elist->num_edges = num_edges;
6442 elist->index_to_edge = (edge *) xmalloc (sizeof (edge) * num_edges);
6446 /* Follow successors of the entry block, and register these edges. */
6447 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
6449 elist->index_to_edge[num_edges] = e;
6453 for (x = 0; x < n_basic_blocks; x++)
6455 basic_block bb = BASIC_BLOCK (x);
6457 /* Follow all successors of blocks, and register these edges. */
6458 for (e = bb->succ; e; e = e->succ_next)
6460 elist->index_to_edge[num_edges] = e;
6467 /* This function free's memory associated with an edge list. */
6469 free_edge_list (elist)
6470 struct edge_list *elist;
6474 free (elist->index_to_edge);
6479 /* This function provides debug output showing an edge list. */
6481 print_edge_list (f, elist)
6483 struct edge_list *elist;
6486 fprintf(f, "Compressed edge list, %d BBs + entry & exit, and %d edges\n",
6487 elist->num_blocks - 2, elist->num_edges);
6489 for (x = 0; x < elist->num_edges; x++)
6491 fprintf (f, " %-4d - edge(", x);
6492 if (INDEX_EDGE_PRED_BB (elist, x) == ENTRY_BLOCK_PTR)
6493 fprintf (f,"entry,");
6495 fprintf (f,"%d,", INDEX_EDGE_PRED_BB (elist, x)->index);
6497 if (INDEX_EDGE_SUCC_BB (elist, x) == EXIT_BLOCK_PTR)
6498 fprintf (f,"exit)\n");
6500 fprintf (f,"%d)\n", INDEX_EDGE_SUCC_BB (elist, x)->index);
6504 /* This function provides an internal consistancy check of an edge list,
6505 verifying that all edges are present, and that there are no
6508 verify_edge_list (f, elist)
6510 struct edge_list *elist;
6512 int x, pred, succ, index;
6515 for (x = 0; x < n_basic_blocks; x++)
6517 basic_block bb = BASIC_BLOCK (x);
6519 for (e = bb->succ; e; e = e->succ_next)
6521 pred = e->src->index;
6522 succ = e->dest->index;
6523 index = EDGE_INDEX (elist, e->src, e->dest);
6524 if (index == EDGE_INDEX_NO_EDGE)
6526 fprintf (f, "*p* No index for edge from %d to %d\n",pred, succ);
6529 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
6530 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
6531 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
6532 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
6533 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
6534 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
6537 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
6539 pred = e->src->index;
6540 succ = e->dest->index;
6541 index = EDGE_INDEX (elist, e->src, e->dest);
6542 if (index == EDGE_INDEX_NO_EDGE)
6544 fprintf (f, "*p* No index for edge from %d to %d\n",pred, succ);
6547 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
6548 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
6549 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
6550 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
6551 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
6552 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
6554 /* We've verified that all the edges are in the list, no lets make sure
6555 there are no spurious edges in the list. */
6557 for (pred = 0 ; pred < n_basic_blocks; pred++)
6558 for (succ = 0 ; succ < n_basic_blocks; succ++)
6560 basic_block p = BASIC_BLOCK (pred);
6561 basic_block s = BASIC_BLOCK (succ);
6565 for (e = p->succ; e; e = e->succ_next)
6571 for (e = s->pred; e; e = e->pred_next)
6577 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
6578 == EDGE_INDEX_NO_EDGE && found_edge != 0)
6579 fprintf (f, "*** Edge (%d, %d) appears to not have an index\n",
6581 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
6582 != EDGE_INDEX_NO_EDGE && found_edge == 0)
6583 fprintf (f, "*** Edge (%d, %d) has index %d, but there is no edge\n",
6584 pred, succ, EDGE_INDEX (elist, BASIC_BLOCK (pred),
6585 BASIC_BLOCK (succ)));
6587 for (succ = 0 ; succ < n_basic_blocks; succ++)
6589 basic_block p = ENTRY_BLOCK_PTR;
6590 basic_block s = BASIC_BLOCK (succ);
6594 for (e = p->succ; e; e = e->succ_next)
6600 for (e = s->pred; e; e = e->pred_next)
6606 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
6607 == EDGE_INDEX_NO_EDGE && found_edge != 0)
6608 fprintf (f, "*** Edge (entry, %d) appears to not have an index\n",
6610 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
6611 != EDGE_INDEX_NO_EDGE && found_edge == 0)
6612 fprintf (f, "*** Edge (entry, %d) has index %d, but no edge exists\n",
6613 succ, EDGE_INDEX (elist, ENTRY_BLOCK_PTR,
6614 BASIC_BLOCK (succ)));
6616 for (pred = 0 ; pred < n_basic_blocks; pred++)
6618 basic_block p = BASIC_BLOCK (pred);
6619 basic_block s = EXIT_BLOCK_PTR;
6623 for (e = p->succ; e; e = e->succ_next)
6629 for (e = s->pred; e; e = e->pred_next)
6635 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
6636 == EDGE_INDEX_NO_EDGE && found_edge != 0)
6637 fprintf (f, "*** Edge (%d, exit) appears to not have an index\n",
6639 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
6640 != EDGE_INDEX_NO_EDGE && found_edge == 0)
6641 fprintf (f, "*** Edge (%d, exit) has index %d, but no edge exists\n",
6642 pred, EDGE_INDEX (elist, BASIC_BLOCK (pred),
6647 /* This routine will determine what, if any, edge there is between
6648 a specified predecessor and successor. */
6651 find_edge_index (edge_list, pred, succ)
6652 struct edge_list *edge_list;
6653 basic_block pred, succ;
6656 for (x = 0; x < NUM_EDGES (edge_list); x++)
6658 if (INDEX_EDGE_PRED_BB (edge_list, x) == pred
6659 && INDEX_EDGE_SUCC_BB (edge_list, x) == succ)
6662 return (EDGE_INDEX_NO_EDGE);
6665 /* This function will remove an edge from the flow graph. */
6670 edge last_pred = NULL;
6671 edge last_succ = NULL;
6673 basic_block src, dest;
6676 for (tmp = src->succ; tmp && tmp != e; tmp = tmp->succ_next)
6682 last_succ->succ_next = e->succ_next;
6684 src->succ = e->succ_next;
6686 for (tmp = dest->pred; tmp && tmp != e; tmp = tmp->pred_next)
6692 last_pred->pred_next = e->pred_next;
6694 dest->pred = e->pred_next;
6700 /* This routine will remove any fake successor edges for a basic block.
6701 When the edge is removed, it is also removed from whatever predecessor
6704 remove_fake_successors (bb)
6708 for (e = bb->succ; e ; )
6712 if ((tmp->flags & EDGE_FAKE) == EDGE_FAKE)
6717 /* This routine will remove all fake edges from the flow graph. If
6718 we remove all fake successors, it will automatically remove all
6719 fake predecessors. */
6721 remove_fake_edges ()
6725 for (x = 0; x < n_basic_blocks; x++)
6726 remove_fake_successors (BASIC_BLOCK (x));
6728 /* We've handled all successors except the entry block's. */
6729 remove_fake_successors (ENTRY_BLOCK_PTR);
6732 /* This functions will add a fake edge between any block which has no
6733 successors, and the exit block. Some data flow equations require these
6736 add_noreturn_fake_exit_edges ()
6740 for (x = 0; x < n_basic_blocks; x++)
6741 if (BASIC_BLOCK (x)->succ == NULL)
6742 make_edge (NULL, BASIC_BLOCK (x), EXIT_BLOCK_PTR, EDGE_FAKE);
6745 /* Dump the list of basic blocks in the bitmap NODES. */
6747 flow_nodes_print (str, nodes, file)
6749 const sbitmap nodes;
6754 fprintf (file, "%s { ", str);
6755 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {fprintf (file, "%d ", node);});
6756 fputs ("}\n", file);
6760 /* Dump the list of exiting edges in the array EDGES. */
6762 flow_exits_print (str, edges, num_edges, file)
6770 fprintf (file, "%s { ", str);
6771 for (i = 0; i < num_edges; i++)
6772 fprintf (file, "%d->%d ", edges[i]->src->index, edges[i]->dest->index);
6773 fputs ("}\n", file);
6777 /* Dump loop related CFG information. */
6779 flow_loops_cfg_dump (loops, file)
6780 const struct loops *loops;
6785 if (! loops->num || ! file || ! loops->cfg.dom)
6788 for (i = 0; i < n_basic_blocks; i++)
6792 fprintf (file, ";; %d succs { ", i);
6793 for (succ = BASIC_BLOCK (i)->succ; succ; succ = succ->succ_next)
6794 fprintf (file, "%d ", succ->dest->index);
6795 flow_nodes_print ("} dom", loops->cfg.dom[i], file);
6799 /* Dump the DFS node order. */
6800 if (loops->cfg.dfs_order)
6802 fputs (";; DFS order: ", file);
6803 for (i = 0; i < n_basic_blocks; i++)
6804 fprintf (file, "%d ", loops->cfg.dfs_order[i]);
6810 /* Return non-zero if the nodes of LOOP are a subset of OUTER. */
6812 flow_loop_nested_p (outer, loop)
6816 return sbitmap_a_subset_b_p (loop->nodes, outer->nodes);
6820 /* Dump the loop information specified by LOOPS to the stream FILE. */
6822 flow_loops_dump (loops, file, verbose)
6823 const struct loops *loops;
6830 num_loops = loops->num;
6831 if (! num_loops || ! file)
6834 fprintf (file, ";; %d loops found, %d levels\n",
6835 num_loops, loops->levels);
6837 for (i = 0; i < num_loops; i++)
6839 struct loop *loop = &loops->array[i];
6841 fprintf (file, ";; loop %d (%d to %d):\n;; header %d, latch %d, pre-header %d, depth %d, level %d, outer %ld\n",
6842 i, INSN_UID (loop->header->head), INSN_UID (loop->latch->end),
6843 loop->header->index, loop->latch->index,
6844 loop->pre_header ? loop->pre_header->index : -1,
6845 loop->depth, loop->level,
6846 (long) (loop->outer ? (loop->outer - loops->array) : -1));
6847 fprintf (file, ";; %d", loop->num_nodes);
6848 flow_nodes_print (" nodes", loop->nodes, file);
6849 fprintf (file, ";; %d", loop->num_exits);
6850 flow_exits_print (" exits", loop->exits, loop->num_exits, file);
6856 for (j = 0; j < i; j++)
6858 struct loop *oloop = &loops->array[j];
6860 if (loop->header == oloop->header)
6865 smaller = loop->num_nodes < oloop->num_nodes;
6867 /* If the union of LOOP and OLOOP is different than
6868 the larger of LOOP and OLOOP then LOOP and OLOOP
6869 must be disjoint. */
6870 disjoint = ! flow_loop_nested_p (smaller ? loop : oloop,
6871 smaller ? oloop : loop);
6872 fprintf (file, ";; loop header %d shared by loops %d, %d %s\n",
6873 loop->header->index, i, j,
6874 disjoint ? "disjoint" : "nested");
6881 /* Print diagnostics to compare our concept of a loop with
6882 what the loop notes say. */
6883 if (GET_CODE (PREV_INSN (loop->first->head)) != NOTE
6884 || NOTE_LINE_NUMBER (PREV_INSN (loop->first->head))
6885 != NOTE_INSN_LOOP_BEG)
6886 fprintf (file, ";; No NOTE_INSN_LOOP_BEG at %d\n",
6887 INSN_UID (PREV_INSN (loop->first->head)));
6888 if (GET_CODE (NEXT_INSN (loop->last->end)) != NOTE
6889 || NOTE_LINE_NUMBER (NEXT_INSN (loop->last->end))
6890 != NOTE_INSN_LOOP_END)
6891 fprintf (file, ";; No NOTE_INSN_LOOP_END at %d\n",
6892 INSN_UID (NEXT_INSN (loop->last->end)));
6897 flow_loops_cfg_dump (loops, file);
6901 /* Free all the memory allocated for LOOPS. */
6903 flow_loops_free (loops)
6904 struct loops *loops;
6913 /* Free the loop descriptors. */
6914 for (i = 0; i < loops->num; i++)
6916 struct loop *loop = &loops->array[i];
6919 sbitmap_free (loop->nodes);
6923 free (loops->array);
6924 loops->array = NULL;
6927 sbitmap_vector_free (loops->cfg.dom);
6928 if (loops->cfg.dfs_order)
6929 free (loops->cfg.dfs_order);
6931 sbitmap_free (loops->shared_headers);
6936 /* Find the exits from the loop using the bitmap of loop nodes NODES
6937 and store in EXITS array. Return the number of exits from the
6940 flow_loop_exits_find (nodes, exits)
6941 const sbitmap nodes;
6950 /* Check all nodes within the loop to see if there are any
6951 successors not in the loop. Note that a node may have multiple
6954 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
6955 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
6957 basic_block dest = e->dest;
6959 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
6967 *exits = (edge *) xmalloc (num_exits * sizeof (edge *));
6969 /* Store all exiting edges into an array. */
6971 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
6972 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
6974 basic_block dest = e->dest;
6976 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
6977 (*exits)[num_exits++] = e;
6985 /* Find the nodes contained within the loop with header HEADER and
6986 latch LATCH and store in NODES. Return the number of nodes within
6989 flow_loop_nodes_find (header, latch, nodes)
6998 stack = (basic_block *) xmalloc (n_basic_blocks * sizeof (basic_block));
7001 /* Start with only the loop header in the set of loop nodes. */
7002 sbitmap_zero (nodes);
7003 SET_BIT (nodes, header->index);
7005 header->loop_depth++;
7007 /* Push the loop latch on to the stack. */
7008 if (! TEST_BIT (nodes, latch->index))
7010 SET_BIT (nodes, latch->index);
7011 latch->loop_depth++;
7013 stack[sp++] = latch;
7022 for (e = node->pred; e; e = e->pred_next)
7024 basic_block ancestor = e->src;
7026 /* If each ancestor not marked as part of loop, add to set of
7027 loop nodes and push on to stack. */
7028 if (ancestor != ENTRY_BLOCK_PTR
7029 && ! TEST_BIT (nodes, ancestor->index))
7031 SET_BIT (nodes, ancestor->index);
7032 ancestor->loop_depth++;
7034 stack[sp++] = ancestor;
7043 /* Compute the depth first search order and store in the array
7044 DFS_ORDER, marking the nodes visited in VISITED. Returns the
7045 number of nodes visited. */
7047 flow_depth_first_order_compute (dfs_order)
7056 /* Allocate stack for back-tracking up CFG. */
7057 stack = (edge *) xmalloc (n_basic_blocks * sizeof (edge));
7060 /* Allocate bitmap to track nodes that have been visited. */
7061 visited = sbitmap_alloc (n_basic_blocks);
7063 /* None of the nodes in the CFG have been visited yet. */
7064 sbitmap_zero (visited);
7066 /* Start with the first successor edge from the entry block. */
7067 e = ENTRY_BLOCK_PTR->succ;
7070 basic_block src = e->src;
7071 basic_block dest = e->dest;
7073 /* Mark that we have visited this node. */
7074 if (src != ENTRY_BLOCK_PTR)
7075 SET_BIT (visited, src->index);
7077 /* If this node has not been visited before, push the current
7078 edge on to the stack and proceed with the first successor
7079 edge of this node. */
7080 if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index)
7088 if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index)
7091 /* DEST has no successors (for example, a non-returning
7092 function is called) so do not push the current edge
7093 but carry on with its next successor. */
7094 dfs_order[dest->index] = n_basic_blocks - ++dfsnum;
7095 SET_BIT (visited, dest->index);
7098 while (! e->succ_next && src != ENTRY_BLOCK_PTR)
7100 dfs_order[src->index] = n_basic_blocks - ++dfsnum;
7102 /* Pop edge off stack. */
7110 sbitmap_free (visited);
7112 /* The number of nodes visited should not be greater than
7114 if (dfsnum > n_basic_blocks)
7117 /* There are some nodes left in the CFG that are unreachable. */
7118 if (dfsnum < n_basic_blocks)
7124 /* Return the block for the pre-header of the loop with header
7125 HEADER where DOM specifies the dominator information. Return NULL if
7126 there is no pre-header. */
7128 flow_loop_pre_header_find (header, dom)
7132 basic_block pre_header;
7135 /* If block p is a predecessor of the header and is the only block
7136 that the header does not dominate, then it is the pre-header. */
7138 for (e = header->pred; e; e = e->pred_next)
7140 basic_block node = e->src;
7142 if (node != ENTRY_BLOCK_PTR
7143 && ! TEST_BIT (dom[node->index], header->index))
7145 if (pre_header == NULL)
7149 /* There are multiple edges into the header from outside
7150 the loop so there is no pre-header block. */
7160 /* Add LOOP to the loop hierarchy tree where PREVLOOP was the loop
7161 previously added. The insertion algorithm assumes that the loops
7162 are added in the order found by a depth first search of the CFG. */
7164 flow_loop_tree_node_add (prevloop, loop)
7165 struct loop *prevloop;
7169 if (flow_loop_nested_p (prevloop, loop))
7171 prevloop->inner = loop;
7172 loop->outer = prevloop;
7176 while (prevloop->outer)
7178 if (flow_loop_nested_p (prevloop->outer, loop))
7180 prevloop->next = loop;
7181 loop->outer = prevloop->outer;
7184 prevloop = prevloop->outer;
7187 prevloop->next = loop;
7192 /* Build the loop hierarchy tree for LOOPS. */
7194 flow_loops_tree_build (loops)
7195 struct loops *loops;
7200 num_loops = loops->num;
7204 /* Root the loop hierarchy tree with the first loop found.
7205 Since we used a depth first search this should be the
7207 loops->tree = &loops->array[0];
7208 loops->tree->outer = loops->tree->inner = loops->tree->next = NULL;
7210 /* Add the remaining loops to the tree. */
7211 for (i = 1; i < num_loops; i++)
7212 flow_loop_tree_node_add (&loops->array[i - 1], &loops->array[i]);
7216 /* Helper function to compute loop nesting depth and enclosed loop level
7217 for the natural loop specified by LOOP at the loop depth DEPTH.
7218 Returns the loop level. */
7220 flow_loop_level_compute (loop, depth)
7230 /* Traverse loop tree assigning depth and computing level as the
7231 maximum level of all the inner loops of this loop. The loop
7232 level is equivalent to the height of the loop in the loop tree
7233 and corresponds to the number of enclosed loop levels (including
7235 for (inner = loop->inner; inner; inner = inner->next)
7239 ilevel = flow_loop_level_compute (inner, depth + 1) + 1;
7244 loop->level = level;
7245 loop->depth = depth;
7250 /* Compute the loop nesting depth and enclosed loop level for the loop
7251 hierarchy tree specfied by LOOPS. Return the maximum enclosed loop
7255 flow_loops_level_compute (loops)
7256 struct loops *loops;
7262 /* Traverse all the outer level loops. */
7263 for (loop = loops->tree; loop; loop = loop->next)
7265 level = flow_loop_level_compute (loop, 1);
7273 /* Find all the natural loops in the function and save in LOOPS structure
7274 and recalculate loop_depth information in basic block structures.
7275 Return the number of natural loops found. */
7278 flow_loops_find (loops)
7279 struct loops *loops;
7290 loops->array = NULL;
7294 /* Taking care of this degenerate case makes the rest of
7295 this code simpler. */
7296 if (n_basic_blocks == 0)
7299 /* Compute the dominators. */
7300 dom = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
7301 compute_flow_dominators (dom, NULL);
7303 /* Count the number of loop edges (back edges). This should be the
7304 same as the number of natural loops. Also clear the loop_depth
7305 and as we work from inner->outer in a loop nest we call
7306 find_loop_nodes_find which will increment loop_depth for nodes
7307 within the current loop, which happens to enclose inner loops. */
7310 for (b = 0; b < n_basic_blocks; b++)
7312 BASIC_BLOCK (b)->loop_depth = 0;
7313 for (e = BASIC_BLOCK (b)->pred; e; e = e->pred_next)
7315 basic_block latch = e->src;
7317 /* Look for back edges where a predecessor is dominated
7318 by this block. A natural loop has a single entry
7319 node (header) that dominates all the nodes in the
7320 loop. It also has single back edge to the header
7321 from a latch node. Note that multiple natural loops
7322 may share the same header. */
7323 if (latch != ENTRY_BLOCK_PTR && TEST_BIT (dom[latch->index], b))
7330 /* Compute depth first search order of the CFG so that outer
7331 natural loops will be found before inner natural loops. */
7332 dfs_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
7333 flow_depth_first_order_compute (dfs_order);
7335 /* Allocate loop structures. */
7337 = (struct loop *) xcalloc (num_loops, sizeof (struct loop));
7339 headers = sbitmap_alloc (n_basic_blocks);
7340 sbitmap_zero (headers);
7342 loops->shared_headers = sbitmap_alloc (n_basic_blocks);
7343 sbitmap_zero (loops->shared_headers);
7345 /* Find and record information about all the natural loops
7348 for (b = 0; b < n_basic_blocks; b++)
7352 /* Search the nodes of the CFG in DFS order that we can find
7353 outer loops first. */
7354 header = BASIC_BLOCK (dfs_order[b]);
7356 /* Look for all the possible latch blocks for this header. */
7357 for (e = header->pred; e; e = e->pred_next)
7359 basic_block latch = e->src;
7361 /* Look for back edges where a predecessor is dominated
7362 by this block. A natural loop has a single entry
7363 node (header) that dominates all the nodes in the
7364 loop. It also has single back edge to the header
7365 from a latch node. Note that multiple natural loops
7366 may share the same header. */
7367 if (latch != ENTRY_BLOCK_PTR
7368 && TEST_BIT (dom[latch->index], header->index))
7372 loop = loops->array + num_loops;
7374 loop->header = header;
7375 loop->latch = latch;
7377 /* Keep track of blocks that are loop headers so
7378 that we can tell which loops should be merged. */
7379 if (TEST_BIT (headers, header->index))
7380 SET_BIT (loops->shared_headers, header->index);
7381 SET_BIT (headers, header->index);
7383 /* Find nodes contained within the loop. */
7384 loop->nodes = sbitmap_alloc (n_basic_blocks);
7386 = flow_loop_nodes_find (header, latch, loop->nodes);
7388 /* Compute first and last blocks within the loop.
7389 These are often the same as the loop header and
7390 loop latch respectively, but this is not always
7393 = BASIC_BLOCK (sbitmap_first_set_bit (loop->nodes));
7395 = BASIC_BLOCK (sbitmap_last_set_bit (loop->nodes));
7397 /* Find edges which exit the loop. Note that a node
7398 may have several exit edges. */
7400 = flow_loop_exits_find (loop->nodes, &loop->exits);
7402 /* Look to see if the loop has a pre-header node. */
7404 = flow_loop_pre_header_find (header, dom);
7411 /* Natural loops with shared headers may either be disjoint or
7412 nested. Disjoint loops with shared headers cannot be inner
7413 loops and should be merged. For now just mark loops that share
7415 for (i = 0; i < num_loops; i++)
7416 if (TEST_BIT (loops->shared_headers, loops->array[i].header->index))
7417 loops->array[i].shared = 1;
7419 sbitmap_free (headers);
7422 loops->num = num_loops;
7424 /* Save CFG derived information to avoid recomputing it. */
7425 loops->cfg.dom = dom;
7426 loops->cfg.dfs_order = dfs_order;
7428 /* Build the loop hierarchy tree. */
7429 flow_loops_tree_build (loops);
7431 /* Assign the loop nesting depth and enclosed loop level for each
7433 loops->levels = flow_loops_level_compute (loops);
7439 /* Return non-zero if edge E enters header of LOOP from outside of LOOP. */
7441 flow_loop_outside_edge_p (loop, e)
7442 const struct loop *loop;
7445 if (e->dest != loop->header)
7447 return (e->src == ENTRY_BLOCK_PTR)
7448 || ! TEST_BIT (loop->nodes, e->src->index);
7452 /* Clear LOG_LINKS fields of insns in a chain. */
7454 clear_log_links (insns)
7458 for (i = insns; i; i = NEXT_INSN (i))
7459 if (GET_RTX_CLASS (GET_CODE (i)) == 'i')