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 "hard-reg-set.h"
128 #include "basic-block.h"
129 #include "insn-config.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 */
205 NULL, /* local_set */
206 NULL, /* global_live_at_start */
207 NULL, /* global_live_at_end */
209 EXIT_BLOCK, /* index */
211 -1, -1, /* eh_beg, eh_end */
216 /* Nonzero if the second flow pass has completed. */
219 /* Maximum register number used in this function, plus one. */
223 /* Indexed by n, giving various register information */
225 varray_type reg_n_info;
227 /* Size of a regset for the current function,
228 in (1) bytes and (2) elements. */
233 /* Regset of regs live when calls to `setjmp'-like functions happen. */
234 /* ??? Does this exist only for the setjmp-clobbered warning message? */
236 regset regs_live_at_setjmp;
238 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
239 that have to go in the same hard reg.
240 The first two regs in the list are a pair, and the next two
241 are another pair, etc. */
244 /* Set of registers that may be eliminable. These are handled specially
245 in updating regs_ever_live. */
247 static HARD_REG_SET elim_reg_set;
249 /* The basic block structure for every insn, indexed by uid. */
251 varray_type basic_block_for_insn;
253 /* The labels mentioned in non-jump rtl. Valid during find_basic_blocks. */
254 /* ??? Should probably be using LABEL_NUSES instead. It would take a
255 bit of surgery to be able to use or co-opt the routines in jump. */
257 static rtx label_value_list;
258 static rtx tail_recursion_label_list;
260 /* Holds information for tracking conditional register life information. */
261 struct reg_cond_life_info
263 /* An EXPR_LIST of conditions under which a register is dead. */
266 /* ??? Could store mask of bytes that are dead, so that we could finally
267 track lifetimes of multi-word registers accessed via subregs. */
270 /* For use in communicating between propagate_block and its subroutines.
271 Holds all information needed to compute life and def-use information. */
273 struct propagate_block_info
275 /* The basic block we're considering. */
278 /* Bit N is set if register N is conditionally or unconditionally live. */
281 /* Bit N is set if register N is set this insn. */
284 /* Element N is the next insn that uses (hard or pseudo) register N
285 within the current basic block; or zero, if there is no such insn. */
288 /* Contains a list of all the MEMs we are tracking for dead store
292 /* If non-null, record the set of registers set in the basic block. */
295 #ifdef HAVE_conditional_execution
296 /* Indexed by register number, holds a reg_cond_life_info for each
297 register that is not unconditionally live or dead. */
298 splay_tree reg_cond_dead;
300 /* Bit N is set if register N is in an expression in reg_cond_dead. */
304 /* Non-zero if the value of CC0 is live. */
307 /* Flags controling the set of information propagate_block collects. */
311 /* Forward declarations */
312 static int count_basic_blocks PARAMS ((rtx));
313 static void find_basic_blocks_1 PARAMS ((rtx));
314 static rtx find_label_refs PARAMS ((rtx, rtx));
315 static void clear_edges PARAMS ((void));
316 static void make_edges PARAMS ((rtx));
317 static void make_label_edge PARAMS ((sbitmap *, basic_block,
319 static void make_eh_edge PARAMS ((sbitmap *, eh_nesting_info *,
320 basic_block, rtx, int));
321 static void mark_critical_edges PARAMS ((void));
322 static void move_stray_eh_region_notes PARAMS ((void));
323 static void record_active_eh_regions PARAMS ((rtx));
325 static void commit_one_edge_insertion PARAMS ((edge));
327 static void delete_unreachable_blocks PARAMS ((void));
328 static void delete_eh_regions PARAMS ((void));
329 static int can_delete_note_p PARAMS ((rtx));
330 static void expunge_block PARAMS ((basic_block));
331 static int can_delete_label_p PARAMS ((rtx));
332 static int tail_recursion_label_p PARAMS ((rtx));
333 static int merge_blocks_move_predecessor_nojumps PARAMS ((basic_block,
335 static int merge_blocks_move_successor_nojumps PARAMS ((basic_block,
337 static int merge_blocks PARAMS ((edge,basic_block,basic_block));
338 static void try_merge_blocks PARAMS ((void));
339 static void tidy_fallthru_edges PARAMS ((void));
340 static int verify_wide_reg_1 PARAMS ((rtx *, void *));
341 static void verify_wide_reg PARAMS ((int, rtx, rtx));
342 static void verify_local_live_at_start PARAMS ((regset, basic_block));
343 static int set_noop_p PARAMS ((rtx));
344 static int noop_move_p PARAMS ((rtx));
345 static void delete_noop_moves PARAMS ((rtx));
346 static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
347 static void notice_stack_pointer_modification PARAMS ((rtx));
348 static void mark_reg PARAMS ((rtx, void *));
349 static void mark_regs_live_at_end PARAMS ((regset));
350 static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
351 static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
352 static void propagate_block_delete_insn PARAMS ((basic_block, rtx));
353 static rtx propagate_block_delete_libcall PARAMS ((basic_block, rtx, rtx));
354 static int insn_dead_p PARAMS ((struct propagate_block_info *,
356 static int libcall_dead_p PARAMS ((struct propagate_block_info *,
358 static void mark_set_regs PARAMS ((struct propagate_block_info *,
360 static void mark_set_1 PARAMS ((struct propagate_block_info *,
361 enum rtx_code, rtx, rtx,
363 #ifdef HAVE_conditional_execution
364 static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
366 static void free_reg_cond_life_info PARAMS ((splay_tree_value));
367 static int flush_reg_cond_reg_1 PARAMS ((splay_tree_node, void *));
368 static void flush_reg_cond_reg PARAMS ((struct propagate_block_info *,
370 static rtx ior_reg_cond PARAMS ((rtx, rtx));
371 static rtx not_reg_cond PARAMS ((rtx));
372 static rtx nand_reg_cond PARAMS ((rtx, rtx));
375 static void find_auto_inc PARAMS ((struct propagate_block_info *,
377 static int try_pre_increment_1 PARAMS ((struct propagate_block_info *,
379 static int try_pre_increment PARAMS ((rtx, rtx, HOST_WIDE_INT));
381 static void mark_used_reg PARAMS ((struct propagate_block_info *,
383 static void mark_used_regs PARAMS ((struct propagate_block_info *,
385 void dump_flow_info PARAMS ((FILE *));
386 void debug_flow_info PARAMS ((void));
387 static void dump_edge_info PARAMS ((FILE *, edge, int));
389 static void invalidate_mems_from_autoinc PARAMS ((struct propagate_block_info *,
391 static void remove_fake_successors PARAMS ((basic_block));
392 static void flow_nodes_print PARAMS ((const char *, const sbitmap, FILE *));
393 static void flow_exits_print PARAMS ((const char *, const edge *, int, FILE *));
394 static void flow_loops_cfg_dump PARAMS ((const struct loops *, FILE *));
395 static int flow_loop_nested_p PARAMS ((struct loop *, struct loop *));
396 static int flow_loop_exits_find PARAMS ((const sbitmap, edge **));
397 static int flow_loop_nodes_find PARAMS ((basic_block, basic_block, sbitmap));
398 static int flow_depth_first_order_compute PARAMS ((int *));
399 static basic_block flow_loop_pre_header_find PARAMS ((basic_block, const sbitmap *));
400 static void flow_loop_tree_node_add PARAMS ((struct loop *, struct loop *));
401 static void flow_loops_tree_build PARAMS ((struct loops *));
402 static int flow_loop_level_compute PARAMS ((struct loop *, int));
403 static int flow_loops_level_compute PARAMS ((struct loops *));
405 /* Find basic blocks of the current function.
406 F is the first insn of the function and NREGS the number of register
410 find_basic_blocks (f, nregs, file)
412 int nregs ATTRIBUTE_UNUSED;
413 FILE *file ATTRIBUTE_UNUSED;
417 /* Flush out existing data. */
418 if (basic_block_info != NULL)
424 /* Clear bb->aux on all extant basic blocks. We'll use this as a
425 tag for reuse during create_basic_block, just in case some pass
426 copies around basic block notes improperly. */
427 for (i = 0; i < n_basic_blocks; ++i)
428 BASIC_BLOCK (i)->aux = NULL;
430 VARRAY_FREE (basic_block_info);
433 n_basic_blocks = count_basic_blocks (f);
435 /* Size the basic block table. The actual structures will be allocated
436 by find_basic_blocks_1, since we want to keep the structure pointers
437 stable across calls to find_basic_blocks. */
438 /* ??? This whole issue would be much simpler if we called find_basic_blocks
439 exactly once, and thereafter we don't have a single long chain of
440 instructions at all until close to the end of compilation when we
441 actually lay them out. */
443 VARRAY_BB_INIT (basic_block_info, n_basic_blocks, "basic_block_info");
445 find_basic_blocks_1 (f);
447 /* Record the block to which an insn belongs. */
448 /* ??? This should be done another way, by which (perhaps) a label is
449 tagged directly with the basic block that it starts. It is used for
450 more than that currently, but IMO that is the only valid use. */
452 max_uid = get_max_uid ();
454 /* Leave space for insns life_analysis makes in some cases for auto-inc.
455 These cases are rare, so we don't need too much space. */
456 max_uid += max_uid / 10;
459 compute_bb_for_insn (max_uid);
461 /* Discover the edges of our cfg. */
462 record_active_eh_regions (f);
463 make_edges (label_value_list);
465 /* Do very simple cleanup now, for the benefit of code that runs between
466 here and cleanup_cfg, e.g. thread_prologue_and_epilogue_insns. */
467 tidy_fallthru_edges ();
469 mark_critical_edges ();
471 #ifdef ENABLE_CHECKING
476 /* Count the basic blocks of the function. */
479 count_basic_blocks (f)
483 register RTX_CODE prev_code;
484 register int count = 0;
486 int call_had_abnormal_edge = 0;
488 prev_code = JUMP_INSN;
489 for (insn = f; insn; insn = NEXT_INSN (insn))
491 register RTX_CODE code = GET_CODE (insn);
493 if (code == CODE_LABEL
494 || (GET_RTX_CLASS (code) == 'i'
495 && (prev_code == JUMP_INSN
496 || prev_code == BARRIER
497 || (prev_code == CALL_INSN && call_had_abnormal_edge))))
500 /* Record whether this call created an edge. */
501 if (code == CALL_INSN)
503 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
504 int region = (note ? INTVAL (XEXP (note, 0)) : 1);
506 call_had_abnormal_edge = 0;
508 /* If there is an EH region or rethrow, we have an edge. */
509 if ((eh_region && region > 0)
510 || find_reg_note (insn, REG_EH_RETHROW, NULL_RTX))
511 call_had_abnormal_edge = 1;
512 else if (nonlocal_goto_handler_labels && region >= 0)
513 /* If there is a nonlocal goto label and the specified
514 region number isn't -1, we have an edge. (0 means
515 no throw, but might have a nonlocal goto). */
516 call_had_abnormal_edge = 1;
521 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
523 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
527 /* The rest of the compiler works a bit smoother when we don't have to
528 check for the edge case of do-nothing functions with no basic blocks. */
531 emit_insn (gen_rtx_USE (VOIDmode, const0_rtx));
538 /* Scan a list of insns for labels referrred to other than by jumps.
539 This is used to scan the alternatives of a call placeholder. */
540 static rtx find_label_refs (f, lvl)
546 for (insn = f; insn; insn = NEXT_INSN (insn))
547 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
551 /* Make a list of all labels referred to other than by jumps
552 (which just don't have the REG_LABEL notes).
554 Make a special exception for labels followed by an ADDR*VEC,
555 as this would be a part of the tablejump setup code.
557 Make a special exception for the eh_return_stub_label, which
558 we know isn't part of any otherwise visible control flow. */
560 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
561 if (REG_NOTE_KIND (note) == REG_LABEL)
563 rtx lab = XEXP (note, 0), next;
565 if (lab == eh_return_stub_label)
567 else if ((next = next_nonnote_insn (lab)) != NULL
568 && GET_CODE (next) == JUMP_INSN
569 && (GET_CODE (PATTERN (next)) == ADDR_VEC
570 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
572 else if (GET_CODE (lab) == NOTE)
575 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
582 /* Find all basic blocks of the function whose first insn is F.
584 Collect and return a list of labels whose addresses are taken. This
585 will be used in make_edges for use with computed gotos. */
588 find_basic_blocks_1 (f)
591 register rtx insn, next;
593 rtx bb_note = NULL_RTX;
594 rtx eh_list = NULL_RTX;
600 /* We process the instructions in a slightly different way than we did
601 previously. This is so that we see a NOTE_BASIC_BLOCK after we have
602 closed out the previous block, so that it gets attached at the proper
603 place. Since this form should be equivalent to the previous,
604 count_basic_blocks continues to use the old form as a check. */
606 for (insn = f; insn; insn = next)
608 enum rtx_code code = GET_CODE (insn);
610 next = NEXT_INSN (insn);
616 int kind = NOTE_LINE_NUMBER (insn);
618 /* Keep a LIFO list of the currently active exception notes. */
619 if (kind == NOTE_INSN_EH_REGION_BEG)
620 eh_list = alloc_INSN_LIST (insn, eh_list);
621 else if (kind == NOTE_INSN_EH_REGION_END)
625 eh_list = XEXP (eh_list, 1);
626 free_INSN_LIST_node (t);
629 /* Look for basic block notes with which to keep the
630 basic_block_info pointers stable. Unthread the note now;
631 we'll put it back at the right place in create_basic_block.
632 Or not at all if we've already found a note in this block. */
633 else if (kind == NOTE_INSN_BASIC_BLOCK)
635 if (bb_note == NULL_RTX)
638 next = flow_delete_insn (insn);
644 /* A basic block starts at a label. If we've closed one off due
645 to a barrier or some such, no need to do it again. */
646 if (head != NULL_RTX)
648 /* While we now have edge lists with which other portions of
649 the compiler might determine a call ending a basic block
650 does not imply an abnormal edge, it will be a bit before
651 everything can be updated. So continue to emit a noop at
652 the end of such a block. */
653 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
655 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
656 end = emit_insn_after (nop, end);
659 create_basic_block (i++, head, end, bb_note);
667 /* A basic block ends at a jump. */
668 if (head == NULL_RTX)
672 /* ??? Make a special check for table jumps. The way this
673 happens is truly and amazingly gross. We are about to
674 create a basic block that contains just a code label and
675 an addr*vec jump insn. Worse, an addr_diff_vec creates
676 its own natural loop.
678 Prevent this bit of brain damage, pasting things together
679 correctly in make_edges.
681 The correct solution involves emitting the table directly
682 on the tablejump instruction as a note, or JUMP_LABEL. */
684 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
685 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
693 goto new_bb_inclusive;
696 /* A basic block ends at a barrier. It may be that an unconditional
697 jump already closed the basic block -- no need to do it again. */
698 if (head == NULL_RTX)
701 /* While we now have edge lists with which other portions of the
702 compiler might determine a call ending a basic block does not
703 imply an abnormal edge, it will be a bit before everything can
704 be updated. So continue to emit a noop at the end of such a
706 if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
708 rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
709 end = emit_insn_after (nop, end);
711 goto new_bb_exclusive;
715 /* Record whether this call created an edge. */
716 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
717 int region = (note ? INTVAL (XEXP (note, 0)) : 1);
718 int call_has_abnormal_edge = 0;
720 if (GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
722 /* Scan each of the alternatives for label refs. */
723 lvl = find_label_refs (XEXP (PATTERN (insn), 0), lvl);
724 lvl = find_label_refs (XEXP (PATTERN (insn), 1), lvl);
725 lvl = find_label_refs (XEXP (PATTERN (insn), 2), lvl);
726 /* Record its tail recursion label, if any. */
727 if (XEXP (PATTERN (insn), 3) != NULL_RTX)
728 trll = alloc_EXPR_LIST (0, XEXP (PATTERN (insn), 3), trll);
731 /* If there is an EH region or rethrow, we have an edge. */
732 if ((eh_list && region > 0)
733 || find_reg_note (insn, REG_EH_RETHROW, NULL_RTX))
734 call_has_abnormal_edge = 1;
735 else if (nonlocal_goto_handler_labels && region >= 0)
736 /* If there is a nonlocal goto label and the specified
737 region number isn't -1, we have an edge. (0 means
738 no throw, but might have a nonlocal goto). */
739 call_has_abnormal_edge = 1;
741 /* A basic block ends at a call that can either throw or
742 do a non-local goto. */
743 if (call_has_abnormal_edge)
746 if (head == NULL_RTX)
751 create_basic_block (i++, head, end, bb_note);
752 head = end = NULL_RTX;
760 if (GET_RTX_CLASS (code) == 'i')
762 if (head == NULL_RTX)
769 if (GET_RTX_CLASS (code) == 'i')
773 /* Make a list of all labels referred to other than by jumps
774 (which just don't have the REG_LABEL notes).
776 Make a special exception for labels followed by an ADDR*VEC,
777 as this would be a part of the tablejump setup code.
779 Make a special exception for the eh_return_stub_label, which
780 we know isn't part of any otherwise visible control flow. */
782 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
783 if (REG_NOTE_KIND (note) == REG_LABEL)
785 rtx lab = XEXP (note, 0), next;
787 if (lab == eh_return_stub_label)
789 else if ((next = next_nonnote_insn (lab)) != NULL
790 && GET_CODE (next) == JUMP_INSN
791 && (GET_CODE (PATTERN (next)) == ADDR_VEC
792 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
794 else if (GET_CODE (lab) == NOTE)
797 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
802 if (head != NULL_RTX)
803 create_basic_block (i++, head, end, bb_note);
805 flow_delete_insn (bb_note);
807 if (i != n_basic_blocks)
810 label_value_list = lvl;
811 tail_recursion_label_list = trll;
814 /* Tidy the CFG by deleting unreachable code and whatnot. */
820 delete_unreachable_blocks ();
821 move_stray_eh_region_notes ();
822 record_active_eh_regions (f);
824 mark_critical_edges ();
826 /* Kill the data we won't maintain. */
827 free_EXPR_LIST_list (&label_value_list);
828 free_EXPR_LIST_list (&tail_recursion_label_list);
831 /* Create a new basic block consisting of the instructions between
832 HEAD and END inclusive. Reuses the note and basic block struct
833 in BB_NOTE, if any. */
836 create_basic_block (index, head, end, bb_note)
838 rtx head, end, bb_note;
843 && ! RTX_INTEGRATED_P (bb_note)
844 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
847 /* If we found an existing note, thread it back onto the chain. */
851 if (GET_CODE (head) == CODE_LABEL)
855 after = PREV_INSN (head);
859 if (after != bb_note && NEXT_INSN (after) != bb_note)
860 reorder_insns (bb_note, bb_note, after);
864 /* Otherwise we must create a note and a basic block structure.
865 Since we allow basic block structs in rtl, give the struct
866 the same lifetime by allocating it off the function obstack
867 rather than using malloc. */
869 bb = (basic_block) obstack_alloc (function_obstack, sizeof (*bb));
870 memset (bb, 0, sizeof (*bb));
872 if (GET_CODE (head) == CODE_LABEL)
873 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
876 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
879 NOTE_BASIC_BLOCK (bb_note) = bb;
882 /* Always include the bb note in the block. */
883 if (NEXT_INSN (end) == bb_note)
889 BASIC_BLOCK (index) = bb;
891 /* Tag the block so that we know it has been used when considering
892 other basic block notes. */
896 /* Records the basic block struct in BB_FOR_INSN, for every instruction
897 indexed by INSN_UID. MAX is the size of the array. */
900 compute_bb_for_insn (max)
905 if (basic_block_for_insn)
906 VARRAY_FREE (basic_block_for_insn);
907 VARRAY_BB_INIT (basic_block_for_insn, max, "basic_block_for_insn");
909 for (i = 0; i < n_basic_blocks; ++i)
911 basic_block bb = BASIC_BLOCK (i);
918 int uid = INSN_UID (insn);
920 VARRAY_BB (basic_block_for_insn, uid) = bb;
923 insn = NEXT_INSN (insn);
928 /* Free the memory associated with the edge structures. */
936 for (i = 0; i < n_basic_blocks; ++i)
938 basic_block bb = BASIC_BLOCK (i);
940 for (e = bb->succ; e ; e = n)
950 for (e = ENTRY_BLOCK_PTR->succ; e ; e = n)
956 ENTRY_BLOCK_PTR->succ = 0;
957 EXIT_BLOCK_PTR->pred = 0;
962 /* Identify the edges between basic blocks.
964 NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks
965 that are otherwise unreachable may be reachable with a non-local goto.
967 BB_EH_END is an array indexed by basic block number in which we record
968 the list of exception regions active at the end of the basic block. */
971 make_edges (label_value_list)
972 rtx label_value_list;
975 eh_nesting_info *eh_nest_info = init_eh_nesting_info ();
976 sbitmap *edge_cache = NULL;
978 /* Assume no computed jump; revise as we create edges. */
979 current_function_has_computed_jump = 0;
981 /* Heavy use of computed goto in machine-generated code can lead to
982 nearly fully-connected CFGs. In that case we spend a significant
983 amount of time searching the edge lists for duplicates. */
984 if (forced_labels || label_value_list)
986 edge_cache = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
987 sbitmap_vector_zero (edge_cache, n_basic_blocks);
990 /* By nature of the way these get numbered, block 0 is always the entry. */
991 make_edge (edge_cache, ENTRY_BLOCK_PTR, BASIC_BLOCK (0), EDGE_FALLTHRU);
993 for (i = 0; i < n_basic_blocks; ++i)
995 basic_block bb = BASIC_BLOCK (i);
998 int force_fallthru = 0;
1000 /* Examine the last instruction of the block, and discover the
1001 ways we can leave the block. */
1004 code = GET_CODE (insn);
1007 if (code == JUMP_INSN)
1011 /* ??? Recognize a tablejump and do the right thing. */
1012 if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1013 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1014 && GET_CODE (tmp) == JUMP_INSN
1015 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1016 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1021 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1022 vec = XVEC (PATTERN (tmp), 0);
1024 vec = XVEC (PATTERN (tmp), 1);
1026 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1027 make_label_edge (edge_cache, bb,
1028 XEXP (RTVEC_ELT (vec, j), 0), 0);
1030 /* Some targets (eg, ARM) emit a conditional jump that also
1031 contains the out-of-range target. Scan for these and
1032 add an edge if necessary. */
1033 if ((tmp = single_set (insn)) != NULL
1034 && SET_DEST (tmp) == pc_rtx
1035 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1036 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF)
1037 make_label_edge (edge_cache, bb,
1038 XEXP (XEXP (SET_SRC (tmp), 2), 0), 0);
1040 #ifdef CASE_DROPS_THROUGH
1041 /* Silly VAXen. The ADDR_VEC is going to be in the way of
1042 us naturally detecting fallthru into the next block. */
1047 /* If this is a computed jump, then mark it as reaching
1048 everything on the label_value_list and forced_labels list. */
1049 else if (computed_jump_p (insn))
1051 current_function_has_computed_jump = 1;
1053 for (x = label_value_list; x; x = XEXP (x, 1))
1054 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1056 for (x = forced_labels; x; x = XEXP (x, 1))
1057 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1060 /* Returns create an exit out. */
1061 else if (returnjump_p (insn))
1062 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, 0);
1064 /* Otherwise, we have a plain conditional or unconditional jump. */
1067 if (! JUMP_LABEL (insn))
1069 make_label_edge (edge_cache, bb, JUMP_LABEL (insn), 0);
1073 /* If this is a sibling call insn, then this is in effect a
1074 combined call and return, and so we need an edge to the
1075 exit block. No need to worry about EH edges, since we
1076 wouldn't have created the sibling call in the first place. */
1078 if (code == CALL_INSN && SIBLING_CALL_P (insn))
1079 make_edge (edge_cache, bb, EXIT_BLOCK_PTR,
1080 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1083 /* If this is a CALL_INSN, then mark it as reaching the active EH
1084 handler for this CALL_INSN. If we're handling asynchronous
1085 exceptions then any insn can reach any of the active handlers.
1087 Also mark the CALL_INSN as reaching any nonlocal goto handler. */
1089 if (code == CALL_INSN || asynchronous_exceptions)
1091 /* Add any appropriate EH edges. We do this unconditionally
1092 since there may be a REG_EH_REGION or REG_EH_RETHROW note
1093 on the call, and this needn't be within an EH region. */
1094 make_eh_edge (edge_cache, eh_nest_info, bb, insn, bb->eh_end);
1096 /* If we have asynchronous exceptions, do the same for *all*
1097 exception regions active in the block. */
1098 if (asynchronous_exceptions
1099 && bb->eh_beg != bb->eh_end)
1101 if (bb->eh_beg >= 0)
1102 make_eh_edge (edge_cache, eh_nest_info, bb,
1103 NULL_RTX, bb->eh_beg);
1105 for (x = bb->head; x != bb->end; x = NEXT_INSN (x))
1106 if (GET_CODE (x) == NOTE
1107 && (NOTE_LINE_NUMBER (x) == NOTE_INSN_EH_REGION_BEG
1108 || NOTE_LINE_NUMBER (x) == NOTE_INSN_EH_REGION_END))
1110 int region = NOTE_EH_HANDLER (x);
1111 make_eh_edge (edge_cache, eh_nest_info, bb,
1116 if (code == CALL_INSN && nonlocal_goto_handler_labels)
1118 /* ??? This could be made smarter: in some cases it's possible
1119 to tell that certain calls will not do a nonlocal goto.
1121 For example, if the nested functions that do the nonlocal
1122 gotos do not have their addresses taken, then only calls to
1123 those functions or to other nested functions that use them
1124 could possibly do nonlocal gotos. */
1125 /* We do know that a REG_EH_REGION note with a value less
1126 than 0 is guaranteed not to perform a non-local goto. */
1127 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
1128 if (!note || INTVAL (XEXP (note, 0)) >= 0)
1129 for (x = nonlocal_goto_handler_labels; x ; x = XEXP (x, 1))
1130 make_label_edge (edge_cache, bb, XEXP (x, 0),
1131 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1135 /* We know something about the structure of the function __throw in
1136 libgcc2.c. It is the only function that ever contains eh_stub
1137 labels. It modifies its return address so that the last block
1138 returns to one of the eh_stub labels within it. So we have to
1139 make additional edges in the flow graph. */
1140 if (i + 1 == n_basic_blocks && eh_return_stub_label != 0)
1141 make_label_edge (edge_cache, bb, eh_return_stub_label, EDGE_EH);
1143 /* Find out if we can drop through to the next block. */
1144 insn = next_nonnote_insn (insn);
1145 if (!insn || (i + 1 == n_basic_blocks && force_fallthru))
1146 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU);
1147 else if (i + 1 < n_basic_blocks)
1149 rtx tmp = BLOCK_HEAD (i + 1);
1150 if (GET_CODE (tmp) == NOTE)
1151 tmp = next_nonnote_insn (tmp);
1152 if (force_fallthru || insn == tmp)
1153 make_edge (edge_cache, bb, BASIC_BLOCK (i + 1), EDGE_FALLTHRU);
1157 free_eh_nesting_info (eh_nest_info);
1159 sbitmap_vector_free (edge_cache);
1162 /* Create an edge between two basic blocks. FLAGS are auxiliary information
1163 about the edge that is accumulated between calls. */
1166 make_edge (edge_cache, src, dst, flags)
1167 sbitmap *edge_cache;
1168 basic_block src, dst;
1174 /* Don't bother with edge cache for ENTRY or EXIT; there aren't that
1175 many edges to them, and we didn't allocate memory for it. */
1176 use_edge_cache = (edge_cache
1177 && src != ENTRY_BLOCK_PTR
1178 && dst != EXIT_BLOCK_PTR);
1180 /* Make sure we don't add duplicate edges. */
1181 if (! use_edge_cache || TEST_BIT (edge_cache[src->index], dst->index))
1182 for (e = src->succ; e ; e = e->succ_next)
1189 e = (edge) xcalloc (1, sizeof (*e));
1192 e->succ_next = src->succ;
1193 e->pred_next = dst->pred;
1202 SET_BIT (edge_cache[src->index], dst->index);
1205 /* Create an edge from a basic block to a label. */
1208 make_label_edge (edge_cache, src, label, flags)
1209 sbitmap *edge_cache;
1214 if (GET_CODE (label) != CODE_LABEL)
1217 /* If the label was never emitted, this insn is junk, but avoid a
1218 crash trying to refer to BLOCK_FOR_INSN (label). This can happen
1219 as a result of a syntax error and a diagnostic has already been
1222 if (INSN_UID (label) == 0)
1225 make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags);
1228 /* Create the edges generated by INSN in REGION. */
1231 make_eh_edge (edge_cache, eh_nest_info, src, insn, region)
1232 sbitmap *edge_cache;
1233 eh_nesting_info *eh_nest_info;
1238 handler_info **handler_list;
1241 is_call = (insn && GET_CODE (insn) == CALL_INSN ? EDGE_ABNORMAL_CALL : 0);
1242 num = reachable_handlers (region, eh_nest_info, insn, &handler_list);
1245 make_label_edge (edge_cache, src, handler_list[num]->handler_label,
1246 EDGE_ABNORMAL | EDGE_EH | is_call);
1250 /* EH_REGION notes appearing between basic blocks is ambiguous, and even
1251 dangerous if we intend to move basic blocks around. Move such notes
1252 into the following block. */
1255 move_stray_eh_region_notes ()
1260 if (n_basic_blocks < 2)
1263 b2 = BASIC_BLOCK (n_basic_blocks - 1);
1264 for (i = n_basic_blocks - 2; i >= 0; --i, b2 = b1)
1266 rtx insn, next, list = NULL_RTX;
1268 b1 = BASIC_BLOCK (i);
1269 for (insn = NEXT_INSN (b1->end); insn != b2->head; insn = next)
1271 next = NEXT_INSN (insn);
1272 if (GET_CODE (insn) == NOTE
1273 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG
1274 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
1276 /* Unlink from the insn chain. */
1277 NEXT_INSN (PREV_INSN (insn)) = next;
1278 PREV_INSN (next) = PREV_INSN (insn);
1281 NEXT_INSN (insn) = list;
1286 if (list == NULL_RTX)
1289 /* Find where to insert these things. */
1291 if (GET_CODE (insn) == CODE_LABEL)
1292 insn = NEXT_INSN (insn);
1296 next = NEXT_INSN (list);
1297 add_insn_after (list, insn);
1303 /* Recompute eh_beg/eh_end for each basic block. */
1306 record_active_eh_regions (f)
1309 rtx insn, eh_list = NULL_RTX;
1311 basic_block bb = BASIC_BLOCK (0);
1313 for (insn = f; insn ; insn = NEXT_INSN (insn))
1315 if (bb->head == insn)
1316 bb->eh_beg = (eh_list ? NOTE_EH_HANDLER (XEXP (eh_list, 0)) : -1);
1318 if (GET_CODE (insn) == NOTE)
1320 int kind = NOTE_LINE_NUMBER (insn);
1321 if (kind == NOTE_INSN_EH_REGION_BEG)
1322 eh_list = alloc_INSN_LIST (insn, eh_list);
1323 else if (kind == NOTE_INSN_EH_REGION_END)
1325 rtx t = XEXP (eh_list, 1);
1326 free_INSN_LIST_node (eh_list);
1331 if (bb->end == insn)
1333 bb->eh_end = (eh_list ? NOTE_EH_HANDLER (XEXP (eh_list, 0)) : -1);
1335 if (i == n_basic_blocks)
1337 bb = BASIC_BLOCK (i);
1342 /* Identify critical edges and set the bits appropriately. */
1345 mark_critical_edges ()
1347 int i, n = n_basic_blocks;
1350 /* We begin with the entry block. This is not terribly important now,
1351 but could be if a front end (Fortran) implemented alternate entry
1353 bb = ENTRY_BLOCK_PTR;
1360 /* (1) Critical edges must have a source with multiple successors. */
1361 if (bb->succ && bb->succ->succ_next)
1363 for (e = bb->succ; e ; e = e->succ_next)
1365 /* (2) Critical edges must have a destination with multiple
1366 predecessors. Note that we know there is at least one
1367 predecessor -- the edge we followed to get here. */
1368 if (e->dest->pred->pred_next)
1369 e->flags |= EDGE_CRITICAL;
1371 e->flags &= ~EDGE_CRITICAL;
1376 for (e = bb->succ; e ; e = e->succ_next)
1377 e->flags &= ~EDGE_CRITICAL;
1382 bb = BASIC_BLOCK (i);
1386 /* Split a (typically critical) edge. Return the new block.
1387 Abort on abnormal edges.
1389 ??? The code generally expects to be called on critical edges.
1390 The case of a block ending in an unconditional jump to a
1391 block with multiple predecessors is not handled optimally. */
1394 split_edge (edge_in)
1397 basic_block old_pred, bb, old_succ;
1402 /* Abnormal edges cannot be split. */
1403 if ((edge_in->flags & EDGE_ABNORMAL) != 0)
1406 old_pred = edge_in->src;
1407 old_succ = edge_in->dest;
1409 /* Remove the existing edge from the destination's pred list. */
1412 for (pp = &old_succ->pred; *pp != edge_in; pp = &(*pp)->pred_next)
1414 *pp = edge_in->pred_next;
1415 edge_in->pred_next = NULL;
1418 /* Create the new structures. */
1419 bb = (basic_block) obstack_alloc (function_obstack, sizeof (*bb));
1420 edge_out = (edge) xcalloc (1, sizeof (*edge_out));
1423 memset (bb, 0, sizeof (*bb));
1425 /* ??? This info is likely going to be out of date very soon. */
1426 if (old_succ->global_live_at_start)
1428 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (function_obstack);
1429 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (function_obstack);
1430 COPY_REG_SET (bb->global_live_at_start, old_succ->global_live_at_start);
1431 COPY_REG_SET (bb->global_live_at_end, old_succ->global_live_at_start);
1436 bb->succ = edge_out;
1437 bb->count = edge_in->count;
1440 edge_in->flags &= ~EDGE_CRITICAL;
1442 edge_out->pred_next = old_succ->pred;
1443 edge_out->succ_next = NULL;
1445 edge_out->dest = old_succ;
1446 edge_out->flags = EDGE_FALLTHRU;
1447 edge_out->probability = REG_BR_PROB_BASE;
1448 edge_out->count = edge_in->count;
1450 old_succ->pred = edge_out;
1452 /* Tricky case -- if there existed a fallthru into the successor
1453 (and we're not it) we must add a new unconditional jump around
1454 the new block we're actually interested in.
1456 Further, if that edge is critical, this means a second new basic
1457 block must be created to hold it. In order to simplify correct
1458 insn placement, do this before we touch the existing basic block
1459 ordering for the block we were really wanting. */
1460 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1463 for (e = edge_out->pred_next; e ; e = e->pred_next)
1464 if (e->flags & EDGE_FALLTHRU)
1469 basic_block jump_block;
1472 if ((e->flags & EDGE_CRITICAL) == 0
1473 && e->src != ENTRY_BLOCK_PTR)
1475 /* Non critical -- we can simply add a jump to the end
1476 of the existing predecessor. */
1477 jump_block = e->src;
1481 /* We need a new block to hold the jump. The simplest
1482 way to do the bulk of the work here is to recursively
1484 jump_block = split_edge (e);
1485 e = jump_block->succ;
1488 /* Now add the jump insn ... */
1489 pos = emit_jump_insn_after (gen_jump (old_succ->head),
1491 jump_block->end = pos;
1492 if (basic_block_for_insn)
1493 set_block_for_insn (pos, jump_block);
1494 emit_barrier_after (pos);
1496 /* ... let jump know that label is in use, ... */
1497 JUMP_LABEL (pos) = old_succ->head;
1498 ++LABEL_NUSES (old_succ->head);
1500 /* ... and clear fallthru on the outgoing edge. */
1501 e->flags &= ~EDGE_FALLTHRU;
1503 /* Continue splitting the interesting edge. */
1507 /* Place the new block just in front of the successor. */
1508 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
1509 if (old_succ == EXIT_BLOCK_PTR)
1510 j = n_basic_blocks - 1;
1512 j = old_succ->index;
1513 for (i = n_basic_blocks - 1; i > j; --i)
1515 basic_block tmp = BASIC_BLOCK (i - 1);
1516 BASIC_BLOCK (i) = tmp;
1519 BASIC_BLOCK (i) = bb;
1522 /* Create the basic block note.
1524 Where we place the note can have a noticable impact on the generated
1525 code. Consider this cfg:
1536 If we need to insert an insn on the edge from block 0 to block 1,
1537 we want to ensure the instructions we insert are outside of any
1538 loop notes that physically sit between block 0 and block 1. Otherwise
1539 we confuse the loop optimizer into thinking the loop is a phony. */
1540 if (old_succ != EXIT_BLOCK_PTR
1541 && PREV_INSN (old_succ->head)
1542 && GET_CODE (PREV_INSN (old_succ->head)) == NOTE
1543 && NOTE_LINE_NUMBER (PREV_INSN (old_succ->head)) == NOTE_INSN_LOOP_BEG)
1544 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
1545 PREV_INSN (old_succ->head));
1546 else if (old_succ != EXIT_BLOCK_PTR)
1547 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, old_succ->head);
1549 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
1550 NOTE_BASIC_BLOCK (bb_note) = bb;
1551 bb->head = bb->end = bb_note;
1553 /* Not quite simple -- for non-fallthru edges, we must adjust the
1554 predecessor's jump instruction to target our new block. */
1555 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1557 rtx tmp, insn = old_pred->end;
1558 rtx old_label = old_succ->head;
1559 rtx new_label = gen_label_rtx ();
1561 if (GET_CODE (insn) != JUMP_INSN)
1564 /* ??? Recognize a tablejump and adjust all matching cases. */
1565 if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1566 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1567 && GET_CODE (tmp) == JUMP_INSN
1568 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1569 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1574 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1575 vec = XVEC (PATTERN (tmp), 0);
1577 vec = XVEC (PATTERN (tmp), 1);
1579 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1580 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
1582 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (VOIDmode, new_label);
1583 --LABEL_NUSES (old_label);
1584 ++LABEL_NUSES (new_label);
1587 /* Handle casesi dispatch insns */
1588 if ((tmp = single_set (insn)) != NULL
1589 && SET_DEST (tmp) == pc_rtx
1590 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1591 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
1592 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
1594 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (VOIDmode,
1596 --LABEL_NUSES (old_label);
1597 ++LABEL_NUSES (new_label);
1602 /* This would have indicated an abnormal edge. */
1603 if (computed_jump_p (insn))
1606 /* A return instruction can't be redirected. */
1607 if (returnjump_p (insn))
1610 /* If the insn doesn't go where we think, we're confused. */
1611 if (JUMP_LABEL (insn) != old_label)
1614 redirect_jump (insn, new_label, 0);
1617 emit_label_before (new_label, bb_note);
1618 bb->head = new_label;
1624 /* Queue instructions for insertion on an edge between two basic blocks.
1625 The new instructions and basic blocks (if any) will not appear in the
1626 CFG until commit_edge_insertions is called. */
1629 insert_insn_on_edge (pattern, e)
1633 /* We cannot insert instructions on an abnormal critical edge.
1634 It will be easier to find the culprit if we die now. */
1635 if ((e->flags & (EDGE_ABNORMAL|EDGE_CRITICAL))
1636 == (EDGE_ABNORMAL|EDGE_CRITICAL))
1639 if (e->insns == NULL_RTX)
1642 push_to_sequence (e->insns);
1644 emit_insn (pattern);
1646 e->insns = get_insns ();
1650 /* Update the CFG for the instructions queued on edge E. */
1653 commit_one_edge_insertion (e)
1656 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
1659 /* Pull the insns off the edge now since the edge might go away. */
1661 e->insns = NULL_RTX;
1663 /* Figure out where to put these things. If the destination has
1664 one predecessor, insert there. Except for the exit block. */
1665 if (e->dest->pred->pred_next == NULL
1666 && e->dest != EXIT_BLOCK_PTR)
1670 /* Get the location correct wrt a code label, and "nice" wrt
1671 a basic block note, and before everything else. */
1673 if (GET_CODE (tmp) == CODE_LABEL)
1674 tmp = NEXT_INSN (tmp);
1675 if (GET_CODE (tmp) == NOTE
1676 && NOTE_LINE_NUMBER (tmp) == NOTE_INSN_BASIC_BLOCK)
1677 tmp = NEXT_INSN (tmp);
1678 if (tmp == bb->head)
1681 after = PREV_INSN (tmp);
1684 /* If the source has one successor and the edge is not abnormal,
1685 insert there. Except for the entry block. */
1686 else if ((e->flags & EDGE_ABNORMAL) == 0
1687 && e->src->succ->succ_next == NULL
1688 && e->src != ENTRY_BLOCK_PTR)
1691 /* It is possible to have a non-simple jump here. Consider a target
1692 where some forms of unconditional jumps clobber a register. This
1693 happens on the fr30 for example.
1695 We know this block has a single successor, so we can just emit
1696 the queued insns before the jump. */
1697 if (GET_CODE (bb->end) == JUMP_INSN)
1703 /* We'd better be fallthru, or we've lost track of what's what. */
1704 if ((e->flags & EDGE_FALLTHRU) == 0)
1711 /* Otherwise we must split the edge. */
1714 bb = split_edge (e);
1718 /* Now that we've found the spot, do the insertion. */
1720 /* Set the new block number for these insns, if structure is allocated. */
1721 if (basic_block_for_insn)
1724 for (i = insns; i != NULL_RTX; i = NEXT_INSN (i))
1725 set_block_for_insn (i, bb);
1730 emit_insns_before (insns, before);
1731 if (before == bb->head)
1734 last = prev_nonnote_insn (before);
1738 last = emit_insns_after (insns, after);
1739 if (after == bb->end)
1743 if (returnjump_p (last))
1745 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1746 This is not currently a problem because this only happens
1747 for the (single) epilogue, which already has a fallthru edge
1751 if (e->dest != EXIT_BLOCK_PTR
1752 || e->succ_next != NULL
1753 || (e->flags & EDGE_FALLTHRU) == 0)
1755 e->flags &= ~EDGE_FALLTHRU;
1757 emit_barrier_after (last);
1761 flow_delete_insn (before);
1763 else if (GET_CODE (last) == JUMP_INSN)
1767 /* Update the CFG for all queued instructions. */
1770 commit_edge_insertions ()
1775 #ifdef ENABLE_CHECKING
1776 verify_flow_info ();
1780 bb = ENTRY_BLOCK_PTR;
1785 for (e = bb->succ; e ; e = next)
1787 next = e->succ_next;
1789 commit_one_edge_insertion (e);
1792 if (++i >= n_basic_blocks)
1794 bb = BASIC_BLOCK (i);
1798 /* Delete all unreachable basic blocks. */
1801 delete_unreachable_blocks ()
1803 basic_block *worklist, *tos;
1804 int deleted_handler;
1809 tos = worklist = (basic_block *) xmalloc (sizeof (basic_block) * n);
1811 /* Use basic_block->aux as a marker. Clear them all. */
1813 for (i = 0; i < n; ++i)
1814 BASIC_BLOCK (i)->aux = NULL;
1816 /* Add our starting points to the worklist. Almost always there will
1817 be only one. It isn't inconcievable that we might one day directly
1818 support Fortran alternate entry points. */
1820 for (e = ENTRY_BLOCK_PTR->succ; e ; e = e->succ_next)
1824 /* Mark the block with a handy non-null value. */
1828 /* Iterate: find everything reachable from what we've already seen. */
1830 while (tos != worklist)
1832 basic_block b = *--tos;
1834 for (e = b->succ; e ; e = e->succ_next)
1842 /* Delete all unreachable basic blocks. Count down so that we don't
1843 interfere with the block renumbering that happens in flow_delete_block. */
1845 deleted_handler = 0;
1847 for (i = n - 1; i >= 0; --i)
1849 basic_block b = BASIC_BLOCK (i);
1852 /* This block was found. Tidy up the mark. */
1855 deleted_handler |= flow_delete_block (b);
1858 tidy_fallthru_edges ();
1860 /* If we deleted an exception handler, we may have EH region begin/end
1861 blocks to remove as well. */
1862 if (deleted_handler)
1863 delete_eh_regions ();
1868 /* Find EH regions for which there is no longer a handler, and delete them. */
1871 delete_eh_regions ()
1875 update_rethrow_references ();
1877 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
1878 if (GET_CODE (insn) == NOTE)
1880 if ((NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG) ||
1881 (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
1883 int num = NOTE_EH_HANDLER (insn);
1884 /* A NULL handler indicates a region is no longer needed,
1885 as long as its rethrow label isn't used. */
1886 if (get_first_handler (num) == NULL && ! rethrow_used (num))
1888 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
1889 NOTE_SOURCE_FILE (insn) = 0;
1895 /* Return true if NOTE is not one of the ones that must be kept paired,
1896 so that we may simply delete them. */
1899 can_delete_note_p (note)
1902 return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED
1903 || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK);
1906 /* Unlink a chain of insns between START and FINISH, leaving notes
1907 that must be paired. */
1910 flow_delete_insn_chain (start, finish)
1913 /* Unchain the insns one by one. It would be quicker to delete all
1914 of these with a single unchaining, rather than one at a time, but
1915 we need to keep the NOTE's. */
1921 next = NEXT_INSN (start);
1922 if (GET_CODE (start) == NOTE && !can_delete_note_p (start))
1924 else if (GET_CODE (start) == CODE_LABEL
1925 && ! can_delete_label_p (start))
1927 const char *name = LABEL_NAME (start);
1928 PUT_CODE (start, NOTE);
1929 NOTE_LINE_NUMBER (start) = NOTE_INSN_DELETED_LABEL;
1930 NOTE_SOURCE_FILE (start) = name;
1933 next = flow_delete_insn (start);
1935 if (start == finish)
1941 /* Delete the insns in a (non-live) block. We physically delete every
1942 non-deleted-note insn, and update the flow graph appropriately.
1944 Return nonzero if we deleted an exception handler. */
1946 /* ??? Preserving all such notes strikes me as wrong. It would be nice
1947 to post-process the stream to remove empty blocks, loops, ranges, etc. */
1950 flow_delete_block (b)
1953 int deleted_handler = 0;
1956 /* If the head of this block is a CODE_LABEL, then it might be the
1957 label for an exception handler which can't be reached.
1959 We need to remove the label from the exception_handler_label list
1960 and remove the associated NOTE_INSN_EH_REGION_BEG and
1961 NOTE_INSN_EH_REGION_END notes. */
1965 never_reached_warning (insn);
1967 if (GET_CODE (insn) == CODE_LABEL)
1969 rtx x, *prev = &exception_handler_labels;
1971 for (x = exception_handler_labels; x; x = XEXP (x, 1))
1973 if (XEXP (x, 0) == insn)
1975 /* Found a match, splice this label out of the EH label list. */
1976 *prev = XEXP (x, 1);
1977 XEXP (x, 1) = NULL_RTX;
1978 XEXP (x, 0) = NULL_RTX;
1980 /* Remove the handler from all regions */
1981 remove_handler (insn);
1982 deleted_handler = 1;
1985 prev = &XEXP (x, 1);
1989 /* Include any jump table following the basic block. */
1991 if (GET_CODE (end) == JUMP_INSN
1992 && (tmp = JUMP_LABEL (end)) != NULL_RTX
1993 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1994 && GET_CODE (tmp) == JUMP_INSN
1995 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1996 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1999 /* Include any barrier that may follow the basic block. */
2000 tmp = next_nonnote_insn (end);
2001 if (tmp && GET_CODE (tmp) == BARRIER)
2004 /* Selectively delete the entire chain. */
2005 flow_delete_insn_chain (insn, end);
2007 /* Remove the edges into and out of this block. Note that there may
2008 indeed be edges in, if we are removing an unreachable loop. */
2012 for (e = b->pred; e ; e = next)
2014 for (q = &e->src->succ; *q != e; q = &(*q)->succ_next)
2017 next = e->pred_next;
2021 for (e = b->succ; e ; e = next)
2023 for (q = &e->dest->pred; *q != e; q = &(*q)->pred_next)
2026 next = e->succ_next;
2035 /* Remove the basic block from the array, and compact behind it. */
2038 return deleted_handler;
2041 /* Remove block B from the basic block array and compact behind it. */
2047 int i, n = n_basic_blocks;
2049 for (i = b->index; i + 1 < n; ++i)
2051 basic_block x = BASIC_BLOCK (i + 1);
2052 BASIC_BLOCK (i) = x;
2056 basic_block_info->num_elements--;
2060 /* Delete INSN by patching it out. Return the next insn. */
2063 flow_delete_insn (insn)
2066 rtx prev = PREV_INSN (insn);
2067 rtx next = NEXT_INSN (insn);
2070 PREV_INSN (insn) = NULL_RTX;
2071 NEXT_INSN (insn) = NULL_RTX;
2072 INSN_DELETED_P (insn) = 1;
2075 NEXT_INSN (prev) = next;
2077 PREV_INSN (next) = prev;
2079 set_last_insn (prev);
2081 if (GET_CODE (insn) == CODE_LABEL)
2082 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2084 /* If deleting a jump, decrement the use count of the label. Deleting
2085 the label itself should happen in the normal course of block merging. */
2086 if (GET_CODE (insn) == JUMP_INSN
2087 && JUMP_LABEL (insn)
2088 && GET_CODE (JUMP_LABEL (insn)) == CODE_LABEL)
2089 LABEL_NUSES (JUMP_LABEL (insn))--;
2091 /* Also if deleting an insn that references a label. */
2092 else if ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX
2093 && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
2094 LABEL_NUSES (XEXP (note, 0))--;
2099 /* True if a given label can be deleted. */
2102 can_delete_label_p (label)
2107 if (LABEL_PRESERVE_P (label))
2110 for (x = forced_labels; x ; x = XEXP (x, 1))
2111 if (label == XEXP (x, 0))
2113 for (x = label_value_list; x ; x = XEXP (x, 1))
2114 if (label == XEXP (x, 0))
2116 for (x = exception_handler_labels; x ; x = XEXP (x, 1))
2117 if (label == XEXP (x, 0))
2120 /* User declared labels must be preserved. */
2121 if (LABEL_NAME (label) != 0)
2128 tail_recursion_label_p (label)
2133 for (x = tail_recursion_label_list; x ; x = XEXP (x, 1))
2134 if (label == XEXP (x, 0))
2140 /* Blocks A and B are to be merged into a single block A. The insns
2141 are already contiguous, hence `nomove'. */
2144 merge_blocks_nomove (a, b)
2148 rtx b_head, b_end, a_end;
2149 rtx del_first = NULL_RTX, del_last = NULL_RTX;
2152 /* If there was a CODE_LABEL beginning B, delete it. */
2155 if (GET_CODE (b_head) == CODE_LABEL)
2157 /* Detect basic blocks with nothing but a label. This can happen
2158 in particular at the end of a function. */
2159 if (b_head == b_end)
2161 del_first = del_last = b_head;
2162 b_head = NEXT_INSN (b_head);
2165 /* Delete the basic block note. */
2166 if (GET_CODE (b_head) == NOTE
2167 && NOTE_LINE_NUMBER (b_head) == NOTE_INSN_BASIC_BLOCK)
2169 if (b_head == b_end)
2174 b_head = NEXT_INSN (b_head);
2177 /* If there was a jump out of A, delete it. */
2179 if (GET_CODE (a_end) == JUMP_INSN)
2183 prev = prev_nonnote_insn (a_end);
2190 /* If this was a conditional jump, we need to also delete
2191 the insn that set cc0. */
2192 if (prev && sets_cc0_p (prev))
2195 prev = prev_nonnote_insn (prev);
2204 else if (GET_CODE (NEXT_INSN (a_end)) == BARRIER)
2205 del_first = NEXT_INSN (a_end);
2207 /* Delete everything marked above as well as crap that might be
2208 hanging out between the two blocks. */
2209 flow_delete_insn_chain (del_first, del_last);
2211 /* Normally there should only be one successor of A and that is B, but
2212 partway though the merge of blocks for conditional_execution we'll
2213 be merging a TEST block with THEN and ELSE successors. Free the
2214 whole lot of them and hope the caller knows what they're doing. */
2216 remove_edge (a->succ);
2218 /* Adjust the edges out of B for the new owner. */
2219 for (e = b->succ; e ; e = e->succ_next)
2223 /* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */
2224 b->pred = b->succ = NULL;
2226 /* Reassociate the insns of B with A. */
2229 if (basic_block_for_insn)
2231 BLOCK_FOR_INSN (b_head) = a;
2232 while (b_head != b_end)
2234 b_head = NEXT_INSN (b_head);
2235 BLOCK_FOR_INSN (b_head) = a;
2245 /* Blocks A and B are to be merged into a single block. A has no incoming
2246 fallthru edge, so it can be moved before B without adding or modifying
2247 any jumps (aside from the jump from A to B). */
2250 merge_blocks_move_predecessor_nojumps (a, b)
2253 rtx start, end, barrier;
2259 barrier = next_nonnote_insn (end);
2260 if (GET_CODE (barrier) != BARRIER)
2262 flow_delete_insn (barrier);
2264 /* Move block and loop notes out of the chain so that we do not
2265 disturb their order.
2267 ??? A better solution would be to squeeze out all the non-nested notes
2268 and adjust the block trees appropriately. Even better would be to have
2269 a tighter connection between block trees and rtl so that this is not
2271 start = squeeze_notes (start, end);
2273 /* Scramble the insn chain. */
2274 if (end != PREV_INSN (b->head))
2275 reorder_insns (start, end, PREV_INSN (b->head));
2279 fprintf (rtl_dump_file, "Moved block %d before %d and merged.\n",
2280 a->index, b->index);
2283 /* Swap the records for the two blocks around. Although we are deleting B,
2284 A is now where B was and we want to compact the BB array from where
2286 BASIC_BLOCK(a->index) = b;
2287 BASIC_BLOCK(b->index) = a;
2289 a->index = b->index;
2292 /* Now blocks A and B are contiguous. Merge them. */
2293 merge_blocks_nomove (a, b);
2298 /* Blocks A and B are to be merged into a single block. B has no outgoing
2299 fallthru edge, so it can be moved after A without adding or modifying
2300 any jumps (aside from the jump from A to B). */
2303 merge_blocks_move_successor_nojumps (a, b)
2306 rtx start, end, barrier;
2310 barrier = NEXT_INSN (end);
2312 /* Recognize a jump table following block B. */
2313 if (GET_CODE (barrier) == CODE_LABEL
2314 && NEXT_INSN (barrier)
2315 && GET_CODE (NEXT_INSN (barrier)) == JUMP_INSN
2316 && (GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_VEC
2317 || GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_DIFF_VEC))
2319 end = NEXT_INSN (barrier);
2320 barrier = NEXT_INSN (end);
2323 /* There had better have been a barrier there. Delete it. */
2324 if (GET_CODE (barrier) != BARRIER)
2326 flow_delete_insn (barrier);
2328 /* Move block and loop notes out of the chain so that we do not
2329 disturb their order.
2331 ??? A better solution would be to squeeze out all the non-nested notes
2332 and adjust the block trees appropriately. Even better would be to have
2333 a tighter connection between block trees and rtl so that this is not
2335 start = squeeze_notes (start, end);
2337 /* Scramble the insn chain. */
2338 reorder_insns (start, end, a->end);
2340 /* Now blocks A and B are contiguous. Merge them. */
2341 merge_blocks_nomove (a, b);
2345 fprintf (rtl_dump_file, "Moved block %d after %d and merged.\n",
2346 b->index, a->index);
2352 /* Attempt to merge basic blocks that are potentially non-adjacent.
2353 Return true iff the attempt succeeded. */
2356 merge_blocks (e, b, c)
2360 /* If C has a tail recursion label, do not merge. There is no
2361 edge recorded from the call_placeholder back to this label, as
2362 that would make optimize_sibling_and_tail_recursive_calls more
2363 complex for no gain. */
2364 if (GET_CODE (c->head) == CODE_LABEL
2365 && tail_recursion_label_p (c->head))
2368 /* If B has a fallthru edge to C, no need to move anything. */
2369 if (e->flags & EDGE_FALLTHRU)
2371 merge_blocks_nomove (b, c);
2375 fprintf (rtl_dump_file, "Merged %d and %d without moving.\n",
2376 b->index, c->index);
2385 int c_has_outgoing_fallthru;
2386 int b_has_incoming_fallthru;
2388 /* We must make sure to not munge nesting of exception regions,
2389 lexical blocks, and loop notes.
2391 The first is taken care of by requiring that the active eh
2392 region at the end of one block always matches the active eh
2393 region at the beginning of the next block.
2395 The later two are taken care of by squeezing out all the notes. */
2397 /* ??? A throw/catch edge (or any abnormal edge) should be rarely
2398 executed and we may want to treat blocks which have two out
2399 edges, one normal, one abnormal as only having one edge for
2400 block merging purposes. */
2402 for (tmp_edge = c->succ; tmp_edge ; tmp_edge = tmp_edge->succ_next)
2403 if (tmp_edge->flags & EDGE_FALLTHRU)
2405 c_has_outgoing_fallthru = (tmp_edge != NULL);
2407 for (tmp_edge = b->pred; tmp_edge ; tmp_edge = tmp_edge->pred_next)
2408 if (tmp_edge->flags & EDGE_FALLTHRU)
2410 b_has_incoming_fallthru = (tmp_edge != NULL);
2412 /* If B does not have an incoming fallthru, and the exception regions
2413 match, then it can be moved immediately before C without introducing
2416 C can not be the first block, so we do not have to worry about
2417 accessing a non-existent block. */
2418 d = BASIC_BLOCK (c->index - 1);
2419 if (! b_has_incoming_fallthru
2420 && d->eh_end == b->eh_beg
2421 && b->eh_end == c->eh_beg)
2422 return merge_blocks_move_predecessor_nojumps (b, c);
2424 /* Otherwise, we're going to try to move C after B. Make sure the
2425 exception regions match.
2427 If B is the last basic block, then we must not try to access the
2428 block structure for block B + 1. Luckily in that case we do not
2429 need to worry about matching exception regions. */
2430 d = (b->index + 1 < n_basic_blocks ? BASIC_BLOCK (b->index + 1) : NULL);
2431 if (b->eh_end == c->eh_beg
2432 && (d == NULL || c->eh_end == d->eh_beg))
2434 /* If C does not have an outgoing fallthru, then it can be moved
2435 immediately after B without introducing or modifying jumps. */
2436 if (! c_has_outgoing_fallthru)
2437 return merge_blocks_move_successor_nojumps (b, c);
2439 /* Otherwise, we'll need to insert an extra jump, and possibly
2440 a new block to contain it. */
2441 /* ??? Not implemented yet. */
2448 /* Top level driver for merge_blocks. */
2455 /* Attempt to merge blocks as made possible by edge removal. If a block
2456 has only one successor, and the successor has only one predecessor,
2457 they may be combined. */
2459 for (i = 0; i < n_basic_blocks; )
2461 basic_block c, b = BASIC_BLOCK (i);
2464 /* A loop because chains of blocks might be combineable. */
2465 while ((s = b->succ) != NULL
2466 && s->succ_next == NULL
2467 && (s->flags & EDGE_EH) == 0
2468 && (c = s->dest) != EXIT_BLOCK_PTR
2469 && c->pred->pred_next == NULL
2470 /* If the jump insn has side effects, we can't kill the edge. */
2471 && (GET_CODE (b->end) != JUMP_INSN
2472 || onlyjump_p (b->end))
2473 && merge_blocks (s, b, c))
2476 /* Don't get confused by the index shift caused by deleting blocks. */
2481 /* The given edge should potentially be a fallthru edge. If that is in
2482 fact true, delete the jump and barriers that are in the way. */
2485 tidy_fallthru_edge (e, b, c)
2491 /* ??? In a late-running flow pass, other folks may have deleted basic
2492 blocks by nopping out blocks, leaving multiple BARRIERs between here
2493 and the target label. They ought to be chastized and fixed.
2495 We can also wind up with a sequence of undeletable labels between
2496 one block and the next.
2498 So search through a sequence of barriers, labels, and notes for
2499 the head of block C and assert that we really do fall through. */
2501 if (next_real_insn (b->end) != next_real_insn (PREV_INSN (c->head)))
2504 /* Remove what will soon cease being the jump insn from the source block.
2505 If block B consisted only of this single jump, turn it into a deleted
2508 if (GET_CODE (q) == JUMP_INSN
2510 && (any_uncondjump_p (q)
2511 || (b->succ == e && e->succ_next == NULL)))
2514 /* If this was a conditional jump, we need to also delete
2515 the insn that set cc0. */
2516 if (any_condjump_p (q) && sets_cc0_p (PREV_INSN (q)))
2523 NOTE_LINE_NUMBER (q) = NOTE_INSN_DELETED;
2524 NOTE_SOURCE_FILE (q) = 0;
2527 b->end = q = PREV_INSN (q);
2530 /* Selectively unlink the sequence. */
2531 if (q != PREV_INSN (c->head))
2532 flow_delete_insn_chain (NEXT_INSN (q), PREV_INSN (c->head));
2534 e->flags |= EDGE_FALLTHRU;
2537 /* Fix up edges that now fall through, or rather should now fall through
2538 but previously required a jump around now deleted blocks. Simplify
2539 the search by only examining blocks numerically adjacent, since this
2540 is how find_basic_blocks created them. */
2543 tidy_fallthru_edges ()
2547 for (i = 1; i < n_basic_blocks; ++i)
2549 basic_block b = BASIC_BLOCK (i - 1);
2550 basic_block c = BASIC_BLOCK (i);
2553 /* We care about simple conditional or unconditional jumps with
2556 If we had a conditional branch to the next instruction when
2557 find_basic_blocks was called, then there will only be one
2558 out edge for the block which ended with the conditional
2559 branch (since we do not create duplicate edges).
2561 Furthermore, the edge will be marked as a fallthru because we
2562 merge the flags for the duplicate edges. So we do not want to
2563 check that the edge is not a FALLTHRU edge. */
2564 if ((s = b->succ) != NULL
2565 && s->succ_next == NULL
2567 /* If the jump insn has side effects, we can't tidy the edge. */
2568 && (GET_CODE (b->end) != JUMP_INSN
2569 || onlyjump_p (b->end)))
2570 tidy_fallthru_edge (s, b, c);
2574 /* Perform data flow analysis.
2575 F is the first insn of the function; FLAGS is a set of PROP_* flags
2576 to be used in accumulating flow info. */
2579 life_analysis (f, file, flags)
2584 #ifdef ELIMINABLE_REGS
2586 static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
2589 /* Record which registers will be eliminated. We use this in
2592 CLEAR_HARD_REG_SET (elim_reg_set);
2594 #ifdef ELIMINABLE_REGS
2595 for (i = 0; i < (int) (sizeof eliminables / sizeof eliminables[0]); i++)
2596 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
2598 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
2602 flags &= PROP_DEATH_NOTES | PROP_REG_INFO;
2604 /* The post-reload life analysis have (on a global basis) the same
2605 registers live as was computed by reload itself. elimination
2606 Otherwise offsets and such may be incorrect.
2608 Reload will make some registers as live even though they do not
2611 We don't want to create new auto-incs after reload, since they
2612 are unlikely to be useful and can cause problems with shared
2614 if (reload_completed)
2615 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
2617 /* We want alias analysis information for local dead store elimination. */
2618 if (flags & PROP_SCAN_DEAD_CODE)
2619 init_alias_analysis ();
2621 /* Always remove no-op moves. Do this before other processing so
2622 that we don't have to keep re-scanning them. */
2623 delete_noop_moves (f);
2625 /* Some targets can emit simpler epilogues if they know that sp was
2626 not ever modified during the function. After reload, of course,
2627 we've already emitted the epilogue so there's no sense searching. */
2628 if (! reload_completed)
2629 notice_stack_pointer_modification (f);
2631 /* Allocate and zero out data structures that will record the
2632 data from lifetime analysis. */
2633 allocate_reg_life_data ();
2634 allocate_bb_life_data ();
2636 /* Find the set of registers live on function exit. */
2637 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
2639 /* "Update" life info from zero. It'd be nice to begin the
2640 relaxation with just the exit and noreturn blocks, but that set
2641 is not immediately handy. */
2643 if (flags & PROP_REG_INFO)
2644 memset (regs_ever_live, 0, sizeof(regs_ever_live));
2645 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
2648 if (flags & PROP_SCAN_DEAD_CODE)
2649 end_alias_analysis ();
2652 dump_flow_info (file);
2654 free_basic_block_vars (1);
2657 /* A subroutine of verify_wide_reg, called through for_each_rtx.
2658 Search for REGNO. If found, abort if it is not wider than word_mode. */
2661 verify_wide_reg_1 (px, pregno)
2666 unsigned int regno = *(int *) pregno;
2668 if (GET_CODE (x) == REG && REGNO (x) == regno)
2670 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
2677 /* A subroutine of verify_local_live_at_start. Search through insns
2678 between HEAD and END looking for register REGNO. */
2681 verify_wide_reg (regno, head, end)
2687 if (GET_RTX_CLASS (GET_CODE (head)) == 'i'
2688 && for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no))
2692 head = NEXT_INSN (head);
2695 /* We didn't find the register at all. Something's way screwy. */
2699 /* A subroutine of update_life_info. Verify that there are no untoward
2700 changes in live_at_start during a local update. */
2703 verify_local_live_at_start (new_live_at_start, bb)
2704 regset new_live_at_start;
2707 if (reload_completed)
2709 /* After reload, there are no pseudos, nor subregs of multi-word
2710 registers. The regsets should exactly match. */
2711 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
2718 /* Find the set of changed registers. */
2719 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
2721 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
2723 /* No registers should die. */
2724 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
2726 /* Verify that the now-live register is wider than word_mode. */
2727 verify_wide_reg (i, bb->head, bb->end);
2732 /* Updates life information starting with the basic blocks set in BLOCKS.
2733 If BLOCKS is null, consider it to be the universal set.
2735 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
2736 we are only expecting local modifications to basic blocks. If we find
2737 extra registers live at the beginning of a block, then we either killed
2738 useful data, or we have a broken split that wants data not provided.
2739 If we find registers removed from live_at_start, that means we have
2740 a broken peephole that is killing a register it shouldn't.
2742 ??? This is not true in one situation -- when a pre-reload splitter
2743 generates subregs of a multi-word pseudo, current life analysis will
2744 lose the kill. So we _can_ have a pseudo go live. How irritating.
2746 Including PROP_REG_INFO does not properly refresh regs_ever_live
2747 unless the caller resets it to zero. */
2750 update_life_info (blocks, extent, prop_flags)
2752 enum update_life_extent extent;
2756 regset_head tmp_head;
2759 tmp = INITIALIZE_REG_SET (tmp_head);
2761 /* For a global update, we go through the relaxation process again. */
2762 if (extent != UPDATE_LIFE_LOCAL)
2764 calculate_global_regs_live (blocks, blocks,
2765 prop_flags & PROP_SCAN_DEAD_CODE);
2767 /* If asked, remove notes from the blocks we'll update. */
2768 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
2769 count_or_remove_death_notes (blocks, 1);
2774 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
2776 basic_block bb = BASIC_BLOCK (i);
2778 COPY_REG_SET (tmp, bb->global_live_at_end);
2779 propagate_block (bb, tmp, (regset) NULL, prop_flags);
2781 if (extent == UPDATE_LIFE_LOCAL)
2782 verify_local_live_at_start (tmp, bb);
2787 for (i = n_basic_blocks - 1; i >= 0; --i)
2789 basic_block bb = BASIC_BLOCK (i);
2791 COPY_REG_SET (tmp, bb->global_live_at_end);
2792 propagate_block (bb, tmp, (regset) NULL, prop_flags);
2794 if (extent == UPDATE_LIFE_LOCAL)
2795 verify_local_live_at_start (tmp, bb);
2801 if (prop_flags & PROP_REG_INFO)
2803 /* The only pseudos that are live at the beginning of the function
2804 are those that were not set anywhere in the function. local-alloc
2805 doesn't know how to handle these correctly, so mark them as not
2806 local to any one basic block. */
2807 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
2808 FIRST_PSEUDO_REGISTER, i,
2809 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
2811 /* We have a problem with any pseudoreg that lives across the setjmp.
2812 ANSI says that if a user variable does not change in value between
2813 the setjmp and the longjmp, then the longjmp preserves it. This
2814 includes longjmp from a place where the pseudo appears dead.
2815 (In principle, the value still exists if it is in scope.)
2816 If the pseudo goes in a hard reg, some other value may occupy
2817 that hard reg where this pseudo is dead, thus clobbering the pseudo.
2818 Conclusion: such a pseudo must not go in a hard reg. */
2819 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
2820 FIRST_PSEUDO_REGISTER, i,
2822 if (regno_reg_rtx[i] != 0)
2824 REG_LIVE_LENGTH (i) = -1;
2825 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
2831 /* Free the variables allocated by find_basic_blocks.
2833 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
2836 free_basic_block_vars (keep_head_end_p)
2837 int keep_head_end_p;
2839 if (basic_block_for_insn)
2841 VARRAY_FREE (basic_block_for_insn);
2842 basic_block_for_insn = NULL;
2845 if (! keep_head_end_p)
2848 VARRAY_FREE (basic_block_info);
2851 ENTRY_BLOCK_PTR->aux = NULL;
2852 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
2853 EXIT_BLOCK_PTR->aux = NULL;
2854 EXIT_BLOCK_PTR->global_live_at_start = NULL;
2858 /* Return nonzero if the destination of SET equals the source. */
2863 rtx src = SET_SRC (set);
2864 rtx dst = SET_DEST (set);
2866 if (GET_CODE (src) == SUBREG && GET_CODE (dst) == SUBREG)
2868 if (SUBREG_WORD (src) != SUBREG_WORD (dst))
2870 src = SUBREG_REG (src);
2871 dst = SUBREG_REG (dst);
2874 return (GET_CODE (src) == REG && GET_CODE (dst) == REG
2875 && REGNO (src) == REGNO (dst));
2878 /* Return nonzero if an insn consists only of SETs, each of which only sets a
2884 rtx pat = PATTERN (insn);
2886 /* Insns carrying these notes are useful later on. */
2887 if (find_reg_note (insn, REG_EQUAL, NULL_RTX))
2890 if (GET_CODE (pat) == SET && set_noop_p (pat))
2893 if (GET_CODE (pat) == PARALLEL)
2896 /* If nothing but SETs of registers to themselves,
2897 this insn can also be deleted. */
2898 for (i = 0; i < XVECLEN (pat, 0); i++)
2900 rtx tem = XVECEXP (pat, 0, i);
2902 if (GET_CODE (tem) == USE
2903 || GET_CODE (tem) == CLOBBER)
2906 if (GET_CODE (tem) != SET || ! set_noop_p (tem))
2915 /* Delete any insns that copy a register to itself. */
2918 delete_noop_moves (f)
2922 for (insn = f; insn; insn = NEXT_INSN (insn))
2924 if (GET_CODE (insn) == INSN && noop_move_p (insn))
2926 PUT_CODE (insn, NOTE);
2927 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
2928 NOTE_SOURCE_FILE (insn) = 0;
2933 /* Determine if the stack pointer is constant over the life of the function.
2934 Only useful before prologues have been emitted. */
2937 notice_stack_pointer_modification_1 (x, pat, data)
2939 rtx pat ATTRIBUTE_UNUSED;
2940 void *data ATTRIBUTE_UNUSED;
2942 if (x == stack_pointer_rtx
2943 /* The stack pointer is only modified indirectly as the result
2944 of a push until later in flow. See the comments in rtl.texi
2945 regarding Embedded Side-Effects on Addresses. */
2946 || (GET_CODE (x) == MEM
2947 && (GET_CODE (XEXP (x, 0)) == PRE_DEC
2948 || GET_CODE (XEXP (x, 0)) == PRE_INC
2949 || GET_CODE (XEXP (x, 0)) == POST_DEC
2950 || GET_CODE (XEXP (x, 0)) == POST_INC)
2951 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
2952 current_function_sp_is_unchanging = 0;
2956 notice_stack_pointer_modification (f)
2961 /* Assume that the stack pointer is unchanging if alloca hasn't
2963 current_function_sp_is_unchanging = !current_function_calls_alloca;
2964 if (! current_function_sp_is_unchanging)
2967 for (insn = f; insn; insn = NEXT_INSN (insn))
2969 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
2971 /* Check if insn modifies the stack pointer. */
2972 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
2974 if (! current_function_sp_is_unchanging)
2980 /* Mark a register in SET. Hard registers in large modes get all
2981 of their component registers set as well. */
2983 mark_reg (reg, xset)
2987 regset set = (regset) xset;
2988 int regno = REGNO (reg);
2990 if (GET_MODE (reg) == BLKmode)
2993 SET_REGNO_REG_SET (set, regno);
2994 if (regno < FIRST_PSEUDO_REGISTER)
2996 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
2998 SET_REGNO_REG_SET (set, regno + n);
3002 /* Mark those regs which are needed at the end of the function as live
3003 at the end of the last basic block. */
3005 mark_regs_live_at_end (set)
3010 /* If exiting needs the right stack value, consider the stack pointer
3011 live at the end of the function. */
3012 if ((HAVE_epilogue && reload_completed)
3013 || ! EXIT_IGNORE_STACK
3014 || (! FRAME_POINTER_REQUIRED
3015 && ! current_function_calls_alloca
3016 && flag_omit_frame_pointer)
3017 || current_function_sp_is_unchanging)
3019 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
3022 /* Mark the frame pointer if needed at the end of the function. If
3023 we end up eliminating it, it will be removed from the live list
3024 of each basic block by reload. */
3026 if (! reload_completed || frame_pointer_needed)
3028 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
3029 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3030 /* If they are different, also mark the hard frame pointer as live */
3031 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
3035 #ifdef PIC_OFFSET_TABLE_REGNUM
3036 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
3037 /* Many architectures have a GP register even without flag_pic.
3038 Assume the pic register is not in use, or will be handled by
3039 other means, if it is not fixed. */
3040 if (fixed_regs[PIC_OFFSET_TABLE_REGNUM])
3041 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
3045 /* Mark all global registers, and all registers used by the epilogue
3046 as being live at the end of the function since they may be
3047 referenced by our caller. */
3048 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3050 #ifdef EPILOGUE_USES
3051 || EPILOGUE_USES (i)
3054 SET_REGNO_REG_SET (set, i);
3056 /* Mark all call-saved registers that we actaully used. */
3057 if (HAVE_epilogue && reload_completed)
3059 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3060 if (! call_used_regs[i] && regs_ever_live[i])
3061 SET_REGNO_REG_SET (set, i);
3064 /* Mark function return value. */
3065 diddle_return_value (mark_reg, set);
3068 /* Callback function for for_each_successor_phi. DATA is a regset.
3069 Sets the SRC_REGNO, the regno of the phi alternative for phi node
3070 INSN, in the regset. */
3073 set_phi_alternative_reg (insn, dest_regno, src_regno, data)
3074 rtx insn ATTRIBUTE_UNUSED;
3075 int dest_regno ATTRIBUTE_UNUSED;
3079 regset live = (regset) data;
3080 SET_REGNO_REG_SET (live, src_regno);
3084 /* Propagate global life info around the graph of basic blocks. Begin
3085 considering blocks with their corresponding bit set in BLOCKS_IN.
3086 If BLOCKS_IN is null, consider it the universal set.
3088 BLOCKS_OUT is set for every block that was changed. */
3091 calculate_global_regs_live (blocks_in, blocks_out, flags)
3092 sbitmap blocks_in, blocks_out;
3095 basic_block *queue, *qhead, *qtail, *qend;
3096 regset tmp, new_live_at_end;
3097 regset_head tmp_head;
3098 regset_head new_live_at_end_head;
3101 tmp = INITIALIZE_REG_SET (tmp_head);
3102 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
3104 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
3105 because the `head == tail' style test for an empty queue doesn't
3106 work with a full queue. */
3107 queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
3109 qhead = qend = queue + n_basic_blocks + 2;
3111 /* Clear out the garbage that might be hanging out in bb->aux. */
3112 for (i = n_basic_blocks - 1; i >= 0; --i)
3113 BASIC_BLOCK (i)->aux = NULL;
3115 /* Queue the blocks set in the initial mask. Do this in reverse block
3116 number order so that we are more likely for the first round to do
3117 useful work. We use AUX non-null to flag that the block is queued. */
3120 EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
3122 basic_block bb = BASIC_BLOCK (i);
3129 for (i = 0; i < n_basic_blocks; ++i)
3131 basic_block bb = BASIC_BLOCK (i);
3138 sbitmap_zero (blocks_out);
3140 while (qhead != qtail)
3142 int rescan, changed;
3151 /* Begin by propogating live_at_start from the successor blocks. */
3152 CLEAR_REG_SET (new_live_at_end);
3153 for (e = bb->succ; e ; e = e->succ_next)
3155 basic_block sb = e->dest;
3156 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
3159 /* Force the stack pointer to be live -- which might not already be
3160 the case for blocks within infinite loops. */
3161 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
3163 /* Regs used in phi nodes are not included in
3164 global_live_at_start, since they are live only along a
3165 particular edge. Set those regs that are live because of a
3166 phi node alternative corresponding to this particular block. */
3168 for_each_successor_phi (bb, &set_phi_alternative_reg,
3171 if (bb == ENTRY_BLOCK_PTR)
3173 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3177 /* On our first pass through this block, we'll go ahead and continue.
3178 Recognize first pass by local_set NULL. On subsequent passes, we
3179 get to skip out early if live_at_end wouldn't have changed. */
3181 if (bb->local_set == NULL)
3183 bb->local_set = OBSTACK_ALLOC_REG_SET (function_obstack);
3188 /* If any bits were removed from live_at_end, we'll have to
3189 rescan the block. This wouldn't be necessary if we had
3190 precalculated local_live, however with PROP_SCAN_DEAD_CODE
3191 local_live is really dependant on live_at_end. */
3192 CLEAR_REG_SET (tmp);
3193 rescan = bitmap_operation (tmp, bb->global_live_at_end,
3194 new_live_at_end, BITMAP_AND_COMPL);
3198 /* Find the set of changed bits. Take this opportunity
3199 to notice that this set is empty and early out. */
3200 CLEAR_REG_SET (tmp);
3201 changed = bitmap_operation (tmp, bb->global_live_at_end,
3202 new_live_at_end, BITMAP_XOR);
3206 /* If any of the changed bits overlap with local_set,
3207 we'll have to rescan the block. Detect overlap by
3208 the AND with ~local_set turning off bits. */
3209 rescan = bitmap_operation (tmp, tmp, bb->local_set,
3214 /* Let our caller know that BB changed enough to require its
3215 death notes updated. */
3217 SET_BIT (blocks_out, bb->index);
3221 /* Add to live_at_start the set of all registers in
3222 new_live_at_end that aren't in the old live_at_end. */
3224 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
3226 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3228 changed = bitmap_operation (bb->global_live_at_start,
3229 bb->global_live_at_start,
3236 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
3238 /* Rescan the block insn by insn to turn (a copy of) live_at_end
3239 into live_at_start. */
3240 propagate_block (bb, new_live_at_end, bb->local_set, flags);
3242 /* If live_at start didn't change, no need to go farther. */
3243 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
3246 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
3249 /* Queue all predecessors of BB so that we may re-examine
3250 their live_at_end. */
3251 for (e = bb->pred; e ; e = e->pred_next)
3253 basic_block pb = e->src;
3254 if (pb->aux == NULL)
3265 FREE_REG_SET (new_live_at_end);
3269 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
3271 basic_block bb = BASIC_BLOCK (i);
3272 FREE_REG_SET (bb->local_set);
3277 for (i = n_basic_blocks - 1; i >= 0; --i)
3279 basic_block bb = BASIC_BLOCK (i);
3280 FREE_REG_SET (bb->local_set);
3287 /* Subroutines of life analysis. */
3289 /* Allocate the permanent data structures that represent the results
3290 of life analysis. Not static since used also for stupid life analysis. */
3293 allocate_bb_life_data ()
3297 for (i = 0; i < n_basic_blocks; i++)
3299 basic_block bb = BASIC_BLOCK (i);
3301 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (function_obstack);
3302 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (function_obstack);
3305 ENTRY_BLOCK_PTR->global_live_at_end
3306 = OBSTACK_ALLOC_REG_SET (function_obstack);
3307 EXIT_BLOCK_PTR->global_live_at_start
3308 = OBSTACK_ALLOC_REG_SET (function_obstack);
3310 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (function_obstack);
3314 allocate_reg_life_data ()
3318 max_regno = max_reg_num ();
3320 /* Recalculate the register space, in case it has grown. Old style
3321 vector oriented regsets would set regset_{size,bytes} here also. */
3322 allocate_reg_info (max_regno, FALSE, FALSE);
3324 /* Reset all the data we'll collect in propagate_block and its
3326 for (i = 0; i < max_regno; i++)
3330 REG_N_DEATHS (i) = 0;
3331 REG_N_CALLS_CROSSED (i) = 0;
3332 REG_LIVE_LENGTH (i) = 0;
3333 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
3337 /* Delete dead instructions for propagate_block. */
3340 propagate_block_delete_insn (bb, insn)
3344 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
3346 /* If the insn referred to a label, and that label was attached to
3347 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
3348 pretty much mandatory to delete it, because the ADDR_VEC may be
3349 referencing labels that no longer exist. */
3353 rtx label = XEXP (inote, 0);
3356 if (LABEL_NUSES (label) == 1
3357 && (next = next_nonnote_insn (label)) != NULL
3358 && GET_CODE (next) == JUMP_INSN
3359 && (GET_CODE (PATTERN (next)) == ADDR_VEC
3360 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
3362 rtx pat = PATTERN (next);
3363 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
3364 int len = XVECLEN (pat, diff_vec_p);
3367 for (i = 0; i < len; i++)
3368 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
3370 flow_delete_insn (next);
3374 if (bb->end == insn)
3375 bb->end = PREV_INSN (insn);
3376 flow_delete_insn (insn);
3379 /* Delete dead libcalls for propagate_block. Return the insn
3380 before the libcall. */
3383 propagate_block_delete_libcall (bb, insn, note)
3387 rtx first = XEXP (note, 0);
3388 rtx before = PREV_INSN (first);
3390 if (insn == bb->end)
3393 flow_delete_insn_chain (first, insn);
3397 /* Update the life-status of regs for one insn. Return the previous insn. */
3400 propagate_one_insn (pbi, insn)
3401 struct propagate_block_info *pbi;
3404 rtx prev = PREV_INSN (insn);
3405 int flags = pbi->flags;
3406 int insn_is_dead = 0;
3407 int libcall_is_dead = 0;
3411 if (! INSN_P (insn))
3414 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
3415 if (flags & PROP_SCAN_DEAD_CODE)
3417 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0,
3419 libcall_is_dead = (insn_is_dead && note != 0
3420 && libcall_dead_p (pbi, PATTERN (insn),
3424 /* We almost certainly don't want to delete prologue or epilogue
3425 instructions. Warn about probable compiler losage. */
3428 && (((HAVE_epilogue || HAVE_prologue)
3429 && prologue_epilogue_contains (insn))
3430 || (HAVE_sibcall_epilogue
3431 && sibcall_epilogue_contains (insn))))
3433 if (flags & PROP_KILL_DEAD_CODE)
3435 warning ("ICE: would have deleted prologue/epilogue insn");
3436 if (!inhibit_warnings)
3439 libcall_is_dead = insn_is_dead = 0;
3442 /* If an instruction consists of just dead store(s) on final pass,
3444 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
3446 /* Record sets. Do this even for dead instructions, since they
3447 would have killed the values if they hadn't been deleted. */
3448 mark_set_regs (pbi, PATTERN (insn), insn);
3450 /* CC0 is now known to be dead. Either this insn used it,
3451 in which case it doesn't anymore, or clobbered it,
3452 so the next insn can't use it. */
3455 if (libcall_is_dead)
3457 prev = propagate_block_delete_libcall (pbi->bb, insn, note);
3458 insn = NEXT_INSN (prev);
3461 propagate_block_delete_insn (pbi->bb, insn);
3466 /* See if this is an increment or decrement that can be merged into
3467 a following memory address. */
3470 register rtx x = single_set (insn);
3472 /* Does this instruction increment or decrement a register? */
3473 if ((flags & PROP_AUTOINC)
3475 && GET_CODE (SET_DEST (x)) == REG
3476 && (GET_CODE (SET_SRC (x)) == PLUS
3477 || GET_CODE (SET_SRC (x)) == MINUS)
3478 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
3479 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
3480 /* Ok, look for a following memory ref we can combine with.
3481 If one is found, change the memory ref to a PRE_INC
3482 or PRE_DEC, cancel this insn, and return 1.
3483 Return 0 if nothing has been done. */
3484 && try_pre_increment_1 (pbi, insn))
3487 #endif /* AUTO_INC_DEC */
3489 CLEAR_REG_SET (pbi->new_set);
3491 /* If this is not the final pass, and this insn is copying the value of
3492 a library call and it's dead, don't scan the insns that perform the
3493 library call, so that the call's arguments are not marked live. */
3494 if (libcall_is_dead)
3496 /* Record the death of the dest reg. */
3497 mark_set_regs (pbi, PATTERN (insn), insn);
3499 insn = XEXP (note, 0);
3500 return PREV_INSN (insn);
3502 else if (GET_CODE (PATTERN (insn)) == SET
3503 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
3504 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
3505 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
3506 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
3507 /* We have an insn to pop a constant amount off the stack.
3508 (Such insns use PLUS regardless of the direction of the stack,
3509 and any insn to adjust the stack by a constant is always a pop.)
3510 These insns, if not dead stores, have no effect on life. */
3514 /* Any regs live at the time of a call instruction must not go
3515 in a register clobbered by calls. Find all regs now live and
3516 record this for them. */
3518 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
3519 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
3520 { REG_N_CALLS_CROSSED (i)++; });
3522 /* Record sets. Do this even for dead instructions, since they
3523 would have killed the values if they hadn't been deleted. */
3524 mark_set_regs (pbi, PATTERN (insn), insn);
3526 if (GET_CODE (insn) == CALL_INSN)
3532 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
3533 cond = COND_EXEC_TEST (PATTERN (insn));
3535 /* Non-constant calls clobber memory. */
3536 if (! CONST_CALL_P (insn))
3537 free_EXPR_LIST_list (&pbi->mem_set_list);
3539 /* There may be extra registers to be clobbered. */
3540 for (note = CALL_INSN_FUNCTION_USAGE (insn);
3542 note = XEXP (note, 1))
3543 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
3544 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
3545 cond, insn, pbi->flags);
3547 /* Calls change all call-used and global registers. */
3548 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3549 if (call_used_regs[i] && ! global_regs[i]
3552 /* We do not want REG_UNUSED notes for these registers. */
3553 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
3555 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
3559 /* If an insn doesn't use CC0, it becomes dead since we assume
3560 that every insn clobbers it. So show it dead here;
3561 mark_used_regs will set it live if it is referenced. */
3566 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
3568 /* Sometimes we may have inserted something before INSN (such as a move)
3569 when we make an auto-inc. So ensure we will scan those insns. */
3571 prev = PREV_INSN (insn);
3574 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
3580 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
3581 cond = COND_EXEC_TEST (PATTERN (insn));
3583 /* Calls use their arguments. */
3584 for (note = CALL_INSN_FUNCTION_USAGE (insn);
3586 note = XEXP (note, 1))
3587 if (GET_CODE (XEXP (note, 0)) == USE)
3588 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
3591 /* The stack ptr is used (honorarily) by a CALL insn. */
3592 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
3594 /* Calls may also reference any of the global registers,
3595 so they are made live. */
3596 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3598 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
3603 /* On final pass, update counts of how many insns in which each reg
3605 if (flags & PROP_REG_INFO)
3606 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
3607 { REG_LIVE_LENGTH (i)++; });
3612 /* Initialize a propagate_block_info struct for public consumption.
3613 Note that the structure itself is opaque to this file, but that
3614 the user can use the regsets provided here. */
3616 struct propagate_block_info *
3617 init_propagate_block_info (bb, live, local_set, flags)
3623 struct propagate_block_info *pbi = xmalloc (sizeof(*pbi));
3626 pbi->reg_live = live;
3627 pbi->mem_set_list = NULL_RTX;
3628 pbi->local_set = local_set;
3632 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
3633 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
3635 pbi->reg_next_use = NULL;
3637 pbi->new_set = BITMAP_XMALLOC ();
3639 #ifdef HAVE_conditional_execution
3640 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
3641 free_reg_cond_life_info);
3642 pbi->reg_cond_reg = BITMAP_XMALLOC ();
3644 /* If this block ends in a conditional branch, for each register live
3645 from one side of the branch and not the other, record the register
3646 as conditionally dead. */
3647 if ((flags & (PROP_DEATH_NOTES | PROP_SCAN_DEAD_CODE))
3648 && GET_CODE (bb->end) == JUMP_INSN
3649 && any_condjump_p (bb->end))
3651 regset_head diff_head;
3652 regset diff = INITIALIZE_REG_SET (diff_head);
3653 basic_block bb_true, bb_false;
3654 rtx cond_true, cond_false;
3657 /* Identify the successor blocks. */
3658 bb_true = bb->succ->dest;
3659 if (bb->succ->succ_next != NULL)
3661 bb_false = bb->succ->succ_next->dest;
3663 if (bb->succ->flags & EDGE_FALLTHRU)
3665 basic_block t = bb_false;
3669 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
3674 /* This can happen with a conditional jump to the next insn. */
3675 if (JUMP_LABEL (bb->end) != bb_true->head)
3678 /* Simplest way to do nothing. */
3682 /* Extract the condition from the branch. */
3683 cond_true = XEXP (SET_SRC (PATTERN (bb->end)), 0);
3684 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
3685 GET_MODE (cond_true), XEXP (cond_true, 0),
3686 XEXP (cond_true, 1));
3687 if (GET_CODE (XEXP (SET_SRC (PATTERN (bb->end)), 1)) == PC)
3690 cond_false = cond_true;
3694 /* Compute which register lead different lives in the successors. */
3695 if (bitmap_operation (diff, bb_true->global_live_at_start,
3696 bb_false->global_live_at_start, BITMAP_XOR))
3698 if (GET_CODE (XEXP (cond_true, 0)) != REG)
3700 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond_true, 0)));
3702 /* For each such register, mark it conditionally dead. */
3703 EXECUTE_IF_SET_IN_REG_SET
3706 struct reg_cond_life_info *rcli;
3709 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
3711 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
3715 rcli->condition = alloc_EXPR_LIST (0, cond, NULL_RTX);
3717 splay_tree_insert (pbi->reg_cond_dead, i,
3718 (splay_tree_value) rcli);
3722 FREE_REG_SET (diff);
3726 /* If this block has no successors, any stores to the frame that aren't
3727 used later in the block are dead. So make a pass over the block
3728 recording any such that are made and show them dead at the end. We do
3729 a very conservative and simple job here. */
3730 if ((flags & PROP_SCAN_DEAD_CODE)
3731 && (bb->succ == NULL
3732 || (bb->succ->succ_next == NULL
3733 && bb->succ->dest == EXIT_BLOCK_PTR)))
3736 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
3737 if (GET_CODE (insn) == INSN
3738 && GET_CODE (PATTERN (insn)) == SET
3739 && GET_CODE (SET_DEST (PATTERN (insn))) == MEM)
3741 rtx mem = SET_DEST (PATTERN (insn));
3743 if (XEXP (mem, 0) == frame_pointer_rtx
3744 || (GET_CODE (XEXP (mem, 0)) == PLUS
3745 && XEXP (XEXP (mem, 0), 0) == frame_pointer_rtx
3746 && GET_CODE (XEXP (XEXP (mem, 0), 1)) == CONST_INT))
3747 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
3754 /* Release a propagate_block_info struct. */
3757 free_propagate_block_info (pbi)
3758 struct propagate_block_info *pbi;
3760 free_EXPR_LIST_list (&pbi->mem_set_list);
3762 BITMAP_XFREE (pbi->new_set);
3764 #ifdef HAVE_conditional_execution
3765 splay_tree_delete (pbi->reg_cond_dead);
3766 BITMAP_XFREE (pbi->reg_cond_reg);
3769 if (pbi->reg_next_use)
3770 free (pbi->reg_next_use);
3775 /* Compute the registers live at the beginning of a basic block BB from
3776 those live at the end.
3778 When called, REG_LIVE contains those live at the end. On return, it
3779 contains those live at the beginning.
3781 LOCAL_SET, if non-null, will be set with all registers killed by
3782 this basic block. */
3785 propagate_block (bb, live, local_set, flags)
3791 struct propagate_block_info *pbi;
3794 pbi = init_propagate_block_info (bb, live, local_set, flags);
3796 if (flags & PROP_REG_INFO)
3800 /* Process the regs live at the end of the block.
3801 Mark them as not local to any one basic block. */
3802 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
3803 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
3806 /* Scan the block an insn at a time from end to beginning. */
3808 for (insn = bb->end; ; insn = prev)
3810 /* If this is a call to `setjmp' et al, warn if any
3811 non-volatile datum is live. */
3812 if ((flags & PROP_REG_INFO)
3813 && GET_CODE (insn) == NOTE
3814 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
3815 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
3817 prev = propagate_one_insn (pbi, insn);
3819 if (insn == bb->head)
3823 free_propagate_block_info (pbi);
3826 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
3827 (SET expressions whose destinations are registers dead after the insn).
3828 NEEDED is the regset that says which regs are alive after the insn.
3830 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
3832 If X is the entire body of an insn, NOTES contains the reg notes
3833 pertaining to the insn. */
3836 insn_dead_p (pbi, x, call_ok, notes)
3837 struct propagate_block_info *pbi;
3840 rtx notes ATTRIBUTE_UNUSED;
3842 enum rtx_code code = GET_CODE (x);
3845 /* If flow is invoked after reload, we must take existing AUTO_INC
3846 expresions into account. */
3847 if (reload_completed)
3849 for ( ; notes; notes = XEXP (notes, 1))
3851 if (REG_NOTE_KIND (notes) == REG_INC)
3853 int regno = REGNO (XEXP (notes, 0));
3855 /* Don't delete insns to set global regs. */
3856 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
3857 || REGNO_REG_SET_P (pbi->reg_live, regno))
3864 /* If setting something that's a reg or part of one,
3865 see if that register's altered value will be live. */
3869 rtx r = SET_DEST (x);
3872 if (GET_CODE (r) == CC0)
3873 return ! pbi->cc0_live;
3876 /* A SET that is a subroutine call cannot be dead. */
3877 if (GET_CODE (SET_SRC (x)) == CALL)
3883 /* Don't eliminate loads from volatile memory or volatile asms. */
3884 else if (volatile_refs_p (SET_SRC (x)))
3887 if (GET_CODE (r) == MEM)
3891 if (MEM_VOLATILE_P (r))
3894 /* Walk the set of memory locations we are currently tracking
3895 and see if one is an identical match to this memory location.
3896 If so, this memory write is dead (remember, we're walking
3897 backwards from the end of the block to the start). */
3898 temp = pbi->mem_set_list;
3901 if (rtx_equal_p (XEXP (temp, 0), r))
3903 temp = XEXP (temp, 1);
3908 while (GET_CODE (r) == SUBREG
3909 || GET_CODE (r) == STRICT_LOW_PART
3910 || GET_CODE (r) == ZERO_EXTRACT)
3913 if (GET_CODE (r) == REG)
3915 int regno = REGNO (r);
3918 if (REGNO_REG_SET_P (pbi->reg_live, regno))
3921 /* If this is a hard register, verify that subsequent
3922 words are not needed. */
3923 if (regno < FIRST_PSEUDO_REGISTER)
3925 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
3928 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
3932 /* Don't delete insns to set global regs. */
3933 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
3936 /* Make sure insns to set the stack pointer aren't deleted. */
3937 if (regno == STACK_POINTER_REGNUM)
3940 /* Make sure insns to set the frame pointer aren't deleted. */
3941 if (regno == FRAME_POINTER_REGNUM
3942 && (! reload_completed || frame_pointer_needed))
3944 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3945 if (regno == HARD_FRAME_POINTER_REGNUM
3946 && (! reload_completed || frame_pointer_needed))
3950 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3951 /* Make sure insns to set arg pointer are never deleted
3952 (if the arg pointer isn't fixed, there will be a USE
3953 for it, so we can treat it normally). */
3954 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
3958 #ifdef PIC_OFFSET_TABLE_REGNUM
3959 /* Before reload, do not allow sets of the pic register
3960 to be deleted. Reload can insert references to
3961 constant pool memory anywhere in the function, making
3962 the PIC register live where it wasn't before. */
3963 if (regno == PIC_OFFSET_TABLE_REGNUM && fixed_regs[regno]
3964 && ! reload_completed)
3968 /* Otherwise, the set is dead. */
3974 /* If performing several activities, insn is dead if each activity
3975 is individually dead. Also, CLOBBERs and USEs can be ignored; a
3976 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
3978 else if (code == PARALLEL)
3980 int i = XVECLEN (x, 0);
3982 for (i--; i >= 0; i--)
3983 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
3984 && GET_CODE (XVECEXP (x, 0, i)) != USE
3985 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
3991 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
3992 is not necessarily true for hard registers. */
3993 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
3994 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
3995 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
3998 /* We do not check other CLOBBER or USE here. An insn consisting of just
3999 a CLOBBER or just a USE should not be deleted. */
4003 /* If X is the pattern of the last insn in a libcall, and assuming X is dead,
4004 return 1 if the entire library call is dead.
4005 This is true if X copies a register (hard or pseudo)
4006 and if the hard return reg of the call insn is dead.
4007 (The caller should have tested the destination of X already for death.)
4009 If this insn doesn't just copy a register, then we don't
4010 have an ordinary libcall. In that case, cse could not have
4011 managed to substitute the source for the dest later on,
4012 so we can assume the libcall is dead.
4014 NEEDED is the bit vector of pseudoregs live before this insn.
4015 NOTE is the REG_RETVAL note of the insn. INSN is the insn itself. */
4018 libcall_dead_p (pbi, x, note, insn)
4019 struct propagate_block_info *pbi;
4024 register RTX_CODE code = GET_CODE (x);
4028 register rtx r = SET_SRC (x);
4029 if (GET_CODE (r) == REG)
4031 rtx call = XEXP (note, 0);
4035 /* Find the call insn. */
4036 while (call != insn && GET_CODE (call) != CALL_INSN)
4037 call = NEXT_INSN (call);
4039 /* If there is none, do nothing special,
4040 since ordinary death handling can understand these insns. */
4044 /* See if the hard reg holding the value is dead.
4045 If this is a PARALLEL, find the call within it. */
4046 call_pat = PATTERN (call);
4047 if (GET_CODE (call_pat) == PARALLEL)
4049 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
4050 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
4051 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
4054 /* This may be a library call that is returning a value
4055 via invisible pointer. Do nothing special, since
4056 ordinary death handling can understand these insns. */
4060 call_pat = XVECEXP (call_pat, 0, i);
4063 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
4069 /* Return 1 if register REGNO was used before it was set, i.e. if it is
4070 live at function entry. Don't count global register variables, variables
4071 in registers that can be used for function arg passing, or variables in
4072 fixed hard registers. */
4075 regno_uninitialized (regno)
4078 if (n_basic_blocks == 0
4079 || (regno < FIRST_PSEUDO_REGISTER
4080 && (global_regs[regno]
4081 || fixed_regs[regno]
4082 || FUNCTION_ARG_REGNO_P (regno))))
4085 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
4088 /* 1 if register REGNO was alive at a place where `setjmp' was called
4089 and was set more than once or is an argument.
4090 Such regs may be clobbered by `longjmp'. */
4093 regno_clobbered_at_setjmp (regno)
4096 if (n_basic_blocks == 0)
4099 return ((REG_N_SETS (regno) > 1
4100 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
4101 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
4104 /* INSN references memory, possibly using autoincrement addressing modes.
4105 Find any entries on the mem_set_list that need to be invalidated due
4106 to an address change. */
4109 invalidate_mems_from_autoinc (pbi, insn)
4110 struct propagate_block_info *pbi;
4113 rtx note = REG_NOTES (insn);
4114 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
4116 if (REG_NOTE_KIND (note) == REG_INC)
4118 rtx temp = pbi->mem_set_list;
4119 rtx prev = NULL_RTX;
4124 next = XEXP (temp, 1);
4125 if (reg_overlap_mentioned_p (XEXP (note, 0), XEXP (temp, 0)))
4127 /* Splice temp out of list. */
4129 XEXP (prev, 1) = next;
4131 pbi->mem_set_list = next;
4132 free_EXPR_LIST_node (temp);
4142 /* Process the registers that are set within X. Their bits are set to
4143 1 in the regset DEAD, because they are dead prior to this insn.
4145 If INSN is nonzero, it is the insn being processed.
4147 FLAGS is the set of operations to perform. */
4150 mark_set_regs (pbi, x, insn)
4151 struct propagate_block_info *pbi;
4154 rtx cond = NULL_RTX;
4158 switch (code = GET_CODE (x))
4162 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
4166 cond = COND_EXEC_TEST (x);
4167 x = COND_EXEC_CODE (x);
4173 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
4175 rtx sub = XVECEXP (x, 0, i);
4176 switch (code = GET_CODE (sub))
4179 if (cond != NULL_RTX)
4182 cond = COND_EXEC_TEST (sub);
4183 sub = COND_EXEC_CODE (sub);
4184 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
4190 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
4205 /* Process a single SET rtx, X. */
4208 mark_set_1 (pbi, code, reg, cond, insn, flags)
4209 struct propagate_block_info *pbi;
4211 rtx reg, cond, insn;
4214 int regno_first = -1, regno_last = -1;
4218 /* Some targets place small structures in registers for
4219 return values of functions. We have to detect this
4220 case specially here to get correct flow information. */
4221 if (GET_CODE (reg) == PARALLEL
4222 && GET_MODE (reg) == BLKmode)
4224 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
4225 mark_set_1 (pbi, code, XVECEXP (reg, 0, i), cond, insn, flags);
4229 /* Modifying just one hardware register of a multi-reg value or just a
4230 byte field of a register does not mean the value from before this insn
4231 is now dead. Of course, if it was dead after it's unused now. */
4233 switch (GET_CODE (reg))
4237 case STRICT_LOW_PART:
4238 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
4240 reg = XEXP (reg, 0);
4241 while (GET_CODE (reg) == SUBREG
4242 || GET_CODE (reg) == ZERO_EXTRACT
4243 || GET_CODE (reg) == SIGN_EXTRACT
4244 || GET_CODE (reg) == STRICT_LOW_PART);
4245 if (GET_CODE (reg) == MEM)
4247 not_dead = REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
4251 regno_last = regno_first = REGNO (reg);
4252 if (regno_first < FIRST_PSEUDO_REGISTER)
4253 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
4257 if (GET_CODE (SUBREG_REG (reg)) == REG)
4259 enum machine_mode outer_mode = GET_MODE (reg);
4260 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
4262 /* Identify the range of registers affected. This is moderately
4263 tricky for hard registers. See alter_subreg. */
4265 regno_last = regno_first = REGNO (SUBREG_REG (reg));
4266 if (regno_first < FIRST_PSEUDO_REGISTER)
4268 #ifdef ALTER_HARD_SUBREG
4269 regno_first = ALTER_HARD_SUBREG (outer_mode, SUBREG_WORD (reg),
4270 inner_mode, regno_first);
4272 regno_first += SUBREG_WORD (reg);
4274 regno_last = (regno_first
4275 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
4277 /* Since we've just adjusted the register number ranges, make
4278 sure REG matches. Otherwise some_was_live will be clear
4279 when it shouldn't have been, and we'll create incorrect
4280 REG_UNUSED notes. */
4281 reg = gen_rtx_REG (outer_mode, regno_first);
4285 /* If the number of words in the subreg is less than the number
4286 of words in the full register, we have a well-defined partial
4287 set. Otherwise the high bits are undefined.
4289 This is only really applicable to pseudos, since we just took
4290 care of multi-word hard registers. */
4291 if (((GET_MODE_SIZE (outer_mode)
4292 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
4293 < ((GET_MODE_SIZE (inner_mode)
4294 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
4295 not_dead = REGNO_REG_SET_P (pbi->reg_live, regno_first);
4297 reg = SUBREG_REG (reg);
4301 reg = SUBREG_REG (reg);
4308 /* If this set is a MEM, then it kills any aliased writes.
4309 If this set is a REG, then it kills any MEMs which use the reg. */
4310 if (flags & PROP_SCAN_DEAD_CODE)
4312 if (GET_CODE (reg) == MEM || GET_CODE (reg) == REG)
4314 rtx temp = pbi->mem_set_list;
4315 rtx prev = NULL_RTX;
4320 next = XEXP (temp, 1);
4321 if ((GET_CODE (reg) == MEM
4322 && output_dependence (XEXP (temp, 0), reg))
4323 || (GET_CODE (reg) == REG
4324 && reg_overlap_mentioned_p (reg, XEXP (temp, 0))))
4326 /* Splice this entry out of the list. */
4328 XEXP (prev, 1) = next;
4330 pbi->mem_set_list = next;
4331 free_EXPR_LIST_node (temp);
4339 /* If the memory reference had embedded side effects (autoincrement
4340 address modes. Then we may need to kill some entries on the
4342 if (insn && GET_CODE (reg) == MEM)
4343 invalidate_mems_from_autoinc (pbi, insn);
4345 if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
4346 /* ??? With more effort we could track conditional memory life. */
4348 /* We do not know the size of a BLKmode store, so we do not track
4349 them for redundant store elimination. */
4350 && GET_MODE (reg) != BLKmode
4351 /* There are no REG_INC notes for SP, so we can't assume we'll see
4352 everything that invalidates it. To be safe, don't eliminate any
4353 stores though SP; none of them should be redundant anyway. */
4354 && ! reg_mentioned_p (stack_pointer_rtx, reg))
4355 pbi->mem_set_list = alloc_EXPR_LIST (0, reg, pbi->mem_set_list);
4358 if (GET_CODE (reg) == REG
4359 && ! (regno_first == FRAME_POINTER_REGNUM
4360 && (! reload_completed || frame_pointer_needed))
4361 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4362 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
4363 && (! reload_completed || frame_pointer_needed))
4365 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4366 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
4370 int some_was_live = 0, some_was_dead = 0;
4372 for (i = regno_first; i <= regno_last; ++i)
4374 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
4376 SET_REGNO_REG_SET (pbi->local_set, i);
4377 if (code != CLOBBER)
4378 SET_REGNO_REG_SET (pbi->new_set, i);
4380 some_was_live |= needed_regno;
4381 some_was_dead |= ! needed_regno;
4384 #ifdef HAVE_conditional_execution
4385 /* Consider conditional death in deciding that the register needs
4387 if (some_was_live && ! not_dead
4388 /* The stack pointer is never dead. Well, not strictly true,
4389 but it's very difficult to tell from here. Hopefully
4390 combine_stack_adjustments will fix up the most egregious
4392 && regno_first != STACK_POINTER_REGNUM)
4394 for (i = regno_first; i <= regno_last; ++i)
4395 if (! mark_regno_cond_dead (pbi, i, cond))
4400 /* Additional data to record if this is the final pass. */
4401 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
4402 | PROP_DEATH_NOTES | PROP_AUTOINC))
4405 register int blocknum = pbi->bb->index;
4408 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4410 y = pbi->reg_next_use[regno_first];
4412 /* The next use is no longer next, since a store intervenes. */
4413 for (i = regno_first; i <= regno_last; ++i)
4414 pbi->reg_next_use[i] = 0;
4417 if (flags & PROP_REG_INFO)
4419 for (i = regno_first; i <= regno_last; ++i)
4421 /* Count (weighted) references, stores, etc. This counts a
4422 register twice if it is modified, but that is correct. */
4423 REG_N_SETS (i) += 1;
4424 REG_N_REFS (i) += (optimize_size ? 1
4425 : pbi->bb->loop_depth + 1);
4427 /* The insns where a reg is live are normally counted
4428 elsewhere, but we want the count to include the insn
4429 where the reg is set, and the normal counting mechanism
4430 would not count it. */
4431 REG_LIVE_LENGTH (i) += 1;
4434 /* If this is a hard reg, record this function uses the reg. */
4435 if (regno_first < FIRST_PSEUDO_REGISTER)
4437 for (i = regno_first; i <= regno_last; i++)
4438 regs_ever_live[i] = 1;
4442 /* Keep track of which basic blocks each reg appears in. */
4443 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
4444 REG_BASIC_BLOCK (regno_first) = blocknum;
4445 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
4446 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
4450 if (! some_was_dead)
4452 if (flags & PROP_LOG_LINKS)
4454 /* Make a logical link from the next following insn
4455 that uses this register, back to this insn.
4456 The following insns have already been processed.
4458 We don't build a LOG_LINK for hard registers containing
4459 in ASM_OPERANDs. If these registers get replaced,
4460 we might wind up changing the semantics of the insn,
4461 even if reload can make what appear to be valid
4462 assignments later. */
4463 if (y && (BLOCK_NUM (y) == blocknum)
4464 && (regno_first >= FIRST_PSEUDO_REGISTER
4465 || asm_noperands (PATTERN (y)) < 0))
4466 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
4471 else if (! some_was_live)
4473 if (flags & PROP_REG_INFO)
4474 REG_N_DEATHS (regno_first) += 1;
4476 if (flags & PROP_DEATH_NOTES)
4478 /* Note that dead stores have already been deleted
4479 when possible. If we get here, we have found a
4480 dead store that cannot be eliminated (because the
4481 same insn does something useful). Indicate this
4482 by marking the reg being set as dying here. */
4484 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
4489 if (flags & PROP_DEATH_NOTES)
4491 /* This is a case where we have a multi-word hard register
4492 and some, but not all, of the words of the register are
4493 needed in subsequent insns. Write REG_UNUSED notes
4494 for those parts that were not needed. This case should
4497 for (i = regno_first; i <= regno_last; ++i)
4498 if (! REGNO_REG_SET_P (pbi->reg_live, i))
4500 = alloc_EXPR_LIST (REG_UNUSED,
4501 gen_rtx_REG (reg_raw_mode[i], i),
4507 /* Mark the register as being dead. */
4510 /* The stack pointer is never dead. Well, not strictly true,
4511 but it's very difficult to tell from here. Hopefully
4512 combine_stack_adjustments will fix up the most egregious
4514 && regno_first != STACK_POINTER_REGNUM)
4516 for (i = regno_first; i <= regno_last; ++i)
4517 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
4520 else if (GET_CODE (reg) == REG)
4522 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
4523 pbi->reg_next_use[regno_first] = 0;
4526 /* If this is the last pass and this is a SCRATCH, show it will be dying
4527 here and count it. */
4528 else if (GET_CODE (reg) == SCRATCH)
4530 if (flags & PROP_DEATH_NOTES)
4532 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
4536 #ifdef HAVE_conditional_execution
4537 /* Mark REGNO conditionally dead. Return true if the register is
4538 now unconditionally dead. */
4541 mark_regno_cond_dead (pbi, regno, cond)
4542 struct propagate_block_info *pbi;
4546 /* If this is a store to a predicate register, the value of the
4547 predicate is changing, we don't know that the predicate as seen
4548 before is the same as that seen after. Flush all dependant
4549 conditions from reg_cond_dead. This will make all such
4550 conditionally live registers unconditionally live. */
4551 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
4552 flush_reg_cond_reg (pbi, regno);
4554 /* If this is an unconditional store, remove any conditional
4555 life that may have existed. */
4556 if (cond == NULL_RTX)
4557 splay_tree_remove (pbi->reg_cond_dead, regno);
4560 splay_tree_node node;
4561 struct reg_cond_life_info *rcli;
4564 /* Otherwise this is a conditional set. Record that fact.
4565 It may have been conditionally used, or there may be a
4566 subsequent set with a complimentary condition. */
4568 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
4571 /* The register was unconditionally live previously.
4572 Record the current condition as the condition under
4573 which it is dead. */
4574 rcli = (struct reg_cond_life_info *)
4575 xmalloc (sizeof (*rcli));
4576 rcli->condition = alloc_EXPR_LIST (0, cond, NULL_RTX);
4577 splay_tree_insert (pbi->reg_cond_dead, regno,
4578 (splay_tree_value) rcli);
4580 SET_REGNO_REG_SET (pbi->reg_cond_reg,
4581 REGNO (XEXP (cond, 0)));
4583 /* Not unconditionaly dead. */
4588 /* The register was conditionally live previously.
4589 Add the new condition to the old. */
4590 rcli = (struct reg_cond_life_info *) node->value;
4591 ncond = rcli->condition;
4592 ncond = ior_reg_cond (ncond, cond);
4594 /* If the register is now unconditionally dead,
4595 remove the entry in the splay_tree. */
4596 if (ncond == const1_rtx)
4597 splay_tree_remove (pbi->reg_cond_dead, regno);
4600 rcli->condition = ncond;
4602 SET_REGNO_REG_SET (pbi->reg_cond_reg,
4603 REGNO (XEXP (cond, 0)));
4605 /* Not unconditionaly dead. */
4614 /* Called from splay_tree_delete for pbi->reg_cond_life. */
4617 free_reg_cond_life_info (value)
4618 splay_tree_value value;
4620 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
4621 free_EXPR_LIST_list (&rcli->condition);
4625 /* Helper function for flush_reg_cond_reg. */
4628 flush_reg_cond_reg_1 (node, data)
4629 splay_tree_node node;
4632 struct reg_cond_life_info *rcli;
4633 int *xdata = (int *) data;
4634 unsigned int regno = xdata[0];
4637 /* Don't need to search if last flushed value was farther on in
4638 the in-order traversal. */
4639 if (xdata[1] >= (int) node->key)
4642 /* Splice out portions of the expression that refer to regno. */
4643 rcli = (struct reg_cond_life_info *) node->value;
4644 c = *(prev = &rcli->condition);
4647 if (regno == REGNO (XEXP (XEXP (c, 0), 0)))
4649 rtx next = XEXP (c, 1);
4650 free_EXPR_LIST_node (c);
4654 c = *(prev = &XEXP (c, 1));
4657 /* If the entire condition is now NULL, signal the node to be removed. */
4658 if (! rcli->condition)
4660 xdata[1] = node->key;
4667 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
4670 flush_reg_cond_reg (pbi, regno)
4671 struct propagate_block_info *pbi;
4678 while (splay_tree_foreach (pbi->reg_cond_dead,
4679 flush_reg_cond_reg_1, pair) == -1)
4680 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
4682 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
4685 /* Logical arithmetic on predicate conditions. IOR, NOT and NAND.
4686 We actually use EXPR_LIST to chain the sub-expressions together
4687 instead of IOR because it's easier to manipulate and we have
4688 the lists.c functions to reuse nodes.
4690 Return a new rtl expression as appropriate. */
4693 ior_reg_cond (old, x)
4696 enum rtx_code x_code;
4700 /* We expect these conditions to be of the form (eq reg 0). */
4701 x_code = GET_CODE (x);
4702 if (GET_RTX_CLASS (x_code) != '<'
4703 || GET_CODE (x_reg = XEXP (x, 0)) != REG
4704 || XEXP (x, 1) != const0_rtx)
4707 /* Search the expression for an existing sub-expression of X_REG. */
4708 for (c = old; c ; c = XEXP (c, 1))
4710 rtx y = XEXP (c, 0);
4711 if (REGNO (XEXP (y, 0)) == REGNO (x_reg))
4713 /* If we find X already present in OLD, we need do nothing. */
4714 if (GET_CODE (y) == x_code)
4717 /* If we find X being a compliment of a condition in OLD,
4718 then the entire condition is true. */
4719 if (GET_CODE (y) == reverse_condition (x_code))
4724 /* Otherwise just add to the chain. */
4725 return alloc_EXPR_LIST (0, x, old);
4732 enum rtx_code x_code;
4735 /* We expect these conditions to be of the form (eq reg 0). */
4736 x_code = GET_CODE (x);
4737 if (GET_RTX_CLASS (x_code) != '<'
4738 || GET_CODE (x_reg = XEXP (x, 0)) != REG
4739 || XEXP (x, 1) != const0_rtx)
4742 return alloc_EXPR_LIST (0, gen_rtx_fmt_ee (reverse_condition (x_code),
4743 VOIDmode, x_reg, const0_rtx),
4748 nand_reg_cond (old, x)
4751 enum rtx_code x_code;
4755 /* We expect these conditions to be of the form (eq reg 0). */
4756 x_code = GET_CODE (x);
4757 if (GET_RTX_CLASS (x_code) != '<'
4758 || GET_CODE (x_reg = XEXP (x, 0)) != REG
4759 || XEXP (x, 1) != const0_rtx)
4762 /* Search the expression for an existing sub-expression of X_REG. */
4764 for (c = *(prev = &old); c ; c = *(prev = &XEXP (c, 1)))
4766 rtx y = XEXP (c, 0);
4767 if (REGNO (XEXP (y, 0)) == REGNO (x_reg))
4769 /* If we find X already present in OLD, then we need to
4771 if (GET_CODE (y) == x_code)
4773 *prev = XEXP (c, 1);
4774 free_EXPR_LIST_node (c);
4775 return old ? old : const0_rtx;
4778 /* If we find X being a compliment of a condition in OLD,
4779 then we need do nothing. */
4780 if (GET_CODE (y) == reverse_condition (x_code))
4785 /* Otherwise, by implication, the register in question is now live for
4786 the inverse of the condition X. */
4787 return alloc_EXPR_LIST (0, gen_rtx_fmt_ee (reverse_condition (x_code),
4788 VOIDmode, x_reg, const0_rtx),
4791 #endif /* HAVE_conditional_execution */
4795 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
4799 find_auto_inc (pbi, x, insn)
4800 struct propagate_block_info *pbi;
4804 rtx addr = XEXP (x, 0);
4805 HOST_WIDE_INT offset = 0;
4808 /* Here we detect use of an index register which might be good for
4809 postincrement, postdecrement, preincrement, or predecrement. */
4811 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
4812 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
4814 if (GET_CODE (addr) == REG)
4817 register int size = GET_MODE_SIZE (GET_MODE (x));
4820 int regno = REGNO (addr);
4822 /* Is the next use an increment that might make auto-increment? */
4823 if ((incr = pbi->reg_next_use[regno]) != 0
4824 && (set = single_set (incr)) != 0
4825 && GET_CODE (set) == SET
4826 && BLOCK_NUM (incr) == BLOCK_NUM (insn)
4827 /* Can't add side effects to jumps; if reg is spilled and
4828 reloaded, there's no way to store back the altered value. */
4829 && GET_CODE (insn) != JUMP_INSN
4830 && (y = SET_SRC (set), GET_CODE (y) == PLUS)
4831 && XEXP (y, 0) == addr
4832 && GET_CODE (XEXP (y, 1)) == CONST_INT
4833 && ((HAVE_POST_INCREMENT
4834 && (INTVAL (XEXP (y, 1)) == size && offset == 0))
4835 || (HAVE_POST_DECREMENT
4836 && (INTVAL (XEXP (y, 1)) == - size && offset == 0))
4837 || (HAVE_PRE_INCREMENT
4838 && (INTVAL (XEXP (y, 1)) == size && offset == size))
4839 || (HAVE_PRE_DECREMENT
4840 && (INTVAL (XEXP (y, 1)) == - size && offset == - size)))
4841 /* Make sure this reg appears only once in this insn. */
4842 && (use = find_use_as_address (PATTERN (insn), addr, offset),
4843 use != 0 && use != (rtx) 1))
4845 rtx q = SET_DEST (set);
4846 enum rtx_code inc_code = (INTVAL (XEXP (y, 1)) == size
4847 ? (offset ? PRE_INC : POST_INC)
4848 : (offset ? PRE_DEC : POST_DEC));
4850 if (dead_or_set_p (incr, addr)
4851 /* Mustn't autoinc an eliminable register. */
4852 && (regno >= FIRST_PSEUDO_REGISTER
4853 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
4855 /* This is the simple case. Try to make the auto-inc. If
4856 we can't, we are done. Otherwise, we will do any
4857 needed updates below. */
4858 if (! validate_change (insn, &XEXP (x, 0),
4859 gen_rtx_fmt_e (inc_code, Pmode, addr),
4863 else if (GET_CODE (q) == REG
4864 /* PREV_INSN used here to check the semi-open interval
4866 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
4867 /* We must also check for sets of q as q may be
4868 a call clobbered hard register and there may
4869 be a call between PREV_INSN (insn) and incr. */
4870 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
4872 /* We have *p followed sometime later by q = p+size.
4873 Both p and q must be live afterward,
4874 and q is not used between INSN and its assignment.
4875 Change it to q = p, ...*q..., q = q+size.
4876 Then fall into the usual case. */
4880 emit_move_insn (q, addr);
4881 insns = get_insns ();
4884 if (basic_block_for_insn)
4885 for (temp = insns; temp; temp = NEXT_INSN (temp))
4886 set_block_for_insn (temp, pbi->bb);
4888 /* If we can't make the auto-inc, or can't make the
4889 replacement into Y, exit. There's no point in making
4890 the change below if we can't do the auto-inc and doing
4891 so is not correct in the pre-inc case. */
4893 validate_change (insn, &XEXP (x, 0),
4894 gen_rtx_fmt_e (inc_code, Pmode, q),
4896 validate_change (incr, &XEXP (y, 0), q, 1);
4897 if (! apply_change_group ())
4900 /* We now know we'll be doing this change, so emit the
4901 new insn(s) and do the updates. */
4902 emit_insns_before (insns, insn);
4904 if (pbi->bb->head == insn)
4905 pbi->bb->head = insns;
4907 /* INCR will become a NOTE and INSN won't contain a
4908 use of ADDR. If a use of ADDR was just placed in
4909 the insn before INSN, make that the next use.
4910 Otherwise, invalidate it. */
4911 if (GET_CODE (PREV_INSN (insn)) == INSN
4912 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
4913 && SET_SRC (PATTERN (PREV_INSN (insn))) == addr)
4914 pbi->reg_next_use[regno] = PREV_INSN (insn);
4916 pbi->reg_next_use[regno] = 0;
4921 /* REGNO is now used in INCR which is below INSN, but it
4922 previously wasn't live here. If we don't mark it as
4923 live, we'll put a REG_DEAD note for it on this insn,
4924 which is incorrect. */
4925 SET_REGNO_REG_SET (pbi->reg_live, regno);
4927 /* If there are any calls between INSN and INCR, show
4928 that REGNO now crosses them. */
4929 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
4930 if (GET_CODE (temp) == CALL_INSN)
4931 REG_N_CALLS_CROSSED (regno)++;
4936 /* If we haven't returned, it means we were able to make the
4937 auto-inc, so update the status. First, record that this insn
4938 has an implicit side effect. */
4941 = alloc_EXPR_LIST (REG_INC, addr, REG_NOTES (insn));
4943 /* Modify the old increment-insn to simply copy
4944 the already-incremented value of our register. */
4945 if (! validate_change (incr, &SET_SRC (set), addr, 0))
4948 /* If that makes it a no-op (copying the register into itself) delete
4949 it so it won't appear to be a "use" and a "set" of this
4951 if (SET_DEST (set) == addr)
4953 /* If the original source was dead, it's dead now. */
4954 rtx note = find_reg_note (incr, REG_DEAD, NULL_RTX);
4955 if (note && XEXP (note, 0) != addr)
4956 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
4958 PUT_CODE (incr, NOTE);
4959 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
4960 NOTE_SOURCE_FILE (incr) = 0;
4963 if (regno >= FIRST_PSEUDO_REGISTER)
4965 /* Count an extra reference to the reg. When a reg is
4966 incremented, spilling it is worse, so we want to make
4967 that less likely. */
4968 REG_N_REFS (regno) += (optimize_size ? 1
4969 : pbi->bb->loop_depth + 1);
4971 /* Count the increment as a setting of the register,
4972 even though it isn't a SET in rtl. */
4973 REG_N_SETS (regno)++;
4978 #endif /* AUTO_INC_DEC */
4981 mark_used_reg (pbi, reg, cond, insn)
4982 struct propagate_block_info *pbi;
4984 rtx cond ATTRIBUTE_UNUSED;
4987 int regno = REGNO (reg);
4988 int some_was_live = REGNO_REG_SET_P (pbi->reg_live, regno);
4989 int some_was_dead = ! some_was_live;
4993 /* A hard reg in a wide mode may really be multiple registers.
4994 If so, mark all of them just like the first. */
4995 if (regno < FIRST_PSEUDO_REGISTER)
4997 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5000 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, regno + n);
5001 some_was_live |= needed_regno;
5002 some_was_dead |= ! needed_regno;
5006 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
5008 /* Record where each reg is used, so when the reg is set we know
5009 the next insn that uses it. */
5010 pbi->reg_next_use[regno] = insn;
5013 if (pbi->flags & PROP_REG_INFO)
5015 if (regno < FIRST_PSEUDO_REGISTER)
5017 /* If this is a register we are going to try to eliminate,
5018 don't mark it live here. If we are successful in
5019 eliminating it, it need not be live unless it is used for
5020 pseudos, in which case it will have been set live when it
5021 was allocated to the pseudos. If the register will not
5022 be eliminated, reload will set it live at that point.
5024 Otherwise, record that this function uses this register. */
5025 /* ??? The PPC backend tries to "eliminate" on the pic
5026 register to itself. This should be fixed. In the mean
5027 time, hack around it. */
5029 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno)
5030 && (regno == FRAME_POINTER_REGNUM
5031 || regno == ARG_POINTER_REGNUM)))
5033 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5035 regs_ever_live[regno + --n] = 1;
5041 /* Keep track of which basic block each reg appears in. */
5043 register int blocknum = pbi->bb->index;
5044 if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN)
5045 REG_BASIC_BLOCK (regno) = blocknum;
5046 else if (REG_BASIC_BLOCK (regno) != blocknum)
5047 REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL;
5049 /* Count (weighted) number of uses of each reg. */
5050 REG_N_REFS (regno) += (optimize_size ? 1
5051 : pbi->bb->loop_depth + 1);
5055 /* Find out if any of the register was set this insn. */
5056 some_not_set = ! REGNO_REG_SET_P (pbi->new_set, regno);
5057 if (regno < FIRST_PSEUDO_REGISTER)
5059 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5061 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, regno + n);
5064 /* Record and count the insns in which a reg dies. If it is used in
5065 this insn and was dead below the insn then it dies in this insn.
5066 If it was set in this insn, we do not make a REG_DEAD note;
5067 likewise if we already made such a note. */
5068 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
5072 /* Check for the case where the register dying partially
5073 overlaps the register set by this insn. */
5074 if (regno < FIRST_PSEUDO_REGISTER
5075 && HARD_REGNO_NREGS (regno, GET_MODE (reg)) > 1)
5077 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5079 some_was_live |= REGNO_REG_SET_P (pbi->new_set, regno + n);
5082 /* If none of the words in X is needed, make a REG_DEAD note.
5083 Otherwise, we must make partial REG_DEAD notes. */
5084 if (! some_was_live)
5086 if ((pbi->flags & PROP_DEATH_NOTES)
5087 && ! find_regno_note (insn, REG_DEAD, regno))
5089 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
5091 if (pbi->flags & PROP_REG_INFO)
5092 REG_N_DEATHS (regno)++;
5096 /* Don't make a REG_DEAD note for a part of a register
5097 that is set in the insn. */
5099 n = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)) - 1;
5100 for (; n >= regno; n--)
5101 if (! REGNO_REG_SET_P (pbi->reg_live, n)
5102 && ! dead_or_set_regno_p (insn, n))
5104 = alloc_EXPR_LIST (REG_DEAD,
5105 gen_rtx_REG (reg_raw_mode[n], n),
5110 SET_REGNO_REG_SET (pbi->reg_live, regno);
5111 if (regno < FIRST_PSEUDO_REGISTER)
5113 n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
5115 SET_REGNO_REG_SET (pbi->reg_live, regno + n);
5118 #ifdef HAVE_conditional_execution
5119 /* If this is a conditional use, record that fact. If it is later
5120 conditionally set, we'll know to kill the register. */
5121 if (cond != NULL_RTX)
5123 splay_tree_node node;
5124 struct reg_cond_life_info *rcli;
5129 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
5132 /* The register was unconditionally live previously.
5133 No need to do anything. */
5137 /* The register was conditionally live previously.
5138 Subtract the new life cond from the old death cond. */
5139 rcli = (struct reg_cond_life_info *) node->value;
5140 ncond = rcli->condition;
5141 ncond = nand_reg_cond (ncond, cond);
5143 /* If the register is now unconditionally live, remove the
5144 entry in the splay_tree. */
5145 if (ncond == const0_rtx)
5147 rcli->condition = NULL_RTX;
5148 splay_tree_remove (pbi->reg_cond_dead, regno);
5151 rcli->condition = ncond;
5156 /* The register was not previously live at all. Record
5157 the condition under which it is still dead. */
5158 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
5159 rcli->condition = not_reg_cond (cond);
5160 splay_tree_insert (pbi->reg_cond_dead, regno,
5161 (splay_tree_value) rcli);
5164 else if (some_was_live)
5166 splay_tree_node node;
5167 struct reg_cond_life_info *rcli;
5169 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
5172 /* The register was conditionally live previously, but is now
5173 unconditionally so. Remove it from the conditionally dead
5174 list, so that a conditional set won't cause us to think
5176 rcli = (struct reg_cond_life_info *) node->value;
5177 rcli->condition = NULL_RTX;
5178 splay_tree_remove (pbi->reg_cond_dead, regno);
5185 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
5186 This is done assuming the registers needed from X are those that
5187 have 1-bits in PBI->REG_LIVE.
5189 INSN is the containing instruction. If INSN is dead, this function
5193 mark_used_regs (pbi, x, cond, insn)
5194 struct propagate_block_info *pbi;
5197 register RTX_CODE code;
5199 int flags = pbi->flags;
5202 code = GET_CODE (x);
5222 /* If we are clobbering a MEM, mark any registers inside the address
5224 if (GET_CODE (XEXP (x, 0)) == MEM)
5225 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
5229 /* Don't bother watching stores to mems if this is not the
5230 final pass. We'll not be deleting dead stores this round. */
5231 if (flags & PROP_SCAN_DEAD_CODE)
5233 /* Invalidate the data for the last MEM stored, but only if MEM is
5234 something that can be stored into. */
5235 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
5236 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
5237 ; /* needn't clear the memory set list */
5240 rtx temp = pbi->mem_set_list;
5241 rtx prev = NULL_RTX;
5246 next = XEXP (temp, 1);
5247 if (anti_dependence (XEXP (temp, 0), x))
5249 /* Splice temp out of the list. */
5251 XEXP (prev, 1) = next;
5253 pbi->mem_set_list = next;
5254 free_EXPR_LIST_node (temp);
5262 /* If the memory reference had embedded side effects (autoincrement
5263 address modes. Then we may need to kill some entries on the
5266 invalidate_mems_from_autoinc (pbi, insn);
5270 if (flags & PROP_AUTOINC)
5271 find_auto_inc (pbi, x, insn);
5276 #ifdef CLASS_CANNOT_CHANGE_MODE
5277 if (GET_CODE (SUBREG_REG (x)) == REG
5278 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
5279 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
5280 GET_MODE (SUBREG_REG (x))))
5281 REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
5284 /* While we're here, optimize this case. */
5286 if (GET_CODE (x) != REG)
5291 /* See a register other than being set => mark it as needed. */
5292 mark_used_reg (pbi, x, cond, insn);
5297 register rtx testreg = SET_DEST (x);
5300 /* If storing into MEM, don't show it as being used. But do
5301 show the address as being used. */
5302 if (GET_CODE (testreg) == MEM)
5305 if (flags & PROP_AUTOINC)
5306 find_auto_inc (pbi, testreg, insn);
5308 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
5309 mark_used_regs (pbi, SET_SRC (x), cond, insn);
5313 /* Storing in STRICT_LOW_PART is like storing in a reg
5314 in that this SET might be dead, so ignore it in TESTREG.
5315 but in some other ways it is like using the reg.
5317 Storing in a SUBREG or a bit field is like storing the entire
5318 register in that if the register's value is not used
5319 then this SET is not needed. */
5320 while (GET_CODE (testreg) == STRICT_LOW_PART
5321 || GET_CODE (testreg) == ZERO_EXTRACT
5322 || GET_CODE (testreg) == SIGN_EXTRACT
5323 || GET_CODE (testreg) == SUBREG)
5325 #ifdef CLASS_CANNOT_CHANGE_MODE
5326 if (GET_CODE (testreg) == SUBREG
5327 && GET_CODE (SUBREG_REG (testreg)) == REG
5328 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
5329 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
5330 GET_MODE (testreg)))
5331 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
5334 /* Modifying a single register in an alternate mode
5335 does not use any of the old value. But these other
5336 ways of storing in a register do use the old value. */
5337 if (GET_CODE (testreg) == SUBREG
5338 && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
5343 testreg = XEXP (testreg, 0);
5346 /* If this is a store into a register, recursively scan the
5347 value being stored. */
5349 if ((GET_CODE (testreg) == PARALLEL
5350 && GET_MODE (testreg) == BLKmode)
5351 || (GET_CODE (testreg) == REG
5352 && (regno = REGNO (testreg),
5353 ! (regno == FRAME_POINTER_REGNUM
5354 && (! reload_completed || frame_pointer_needed)))
5355 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
5356 && ! (regno == HARD_FRAME_POINTER_REGNUM
5357 && (! reload_completed || frame_pointer_needed))
5359 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
5360 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
5365 mark_used_regs (pbi, SET_DEST (x), cond, insn);
5366 mark_used_regs (pbi, SET_SRC (x), cond, insn);
5373 case UNSPEC_VOLATILE:
5377 /* Traditional and volatile asm instructions must be considered to use
5378 and clobber all hard registers, all pseudo-registers and all of
5379 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
5381 Consider for instance a volatile asm that changes the fpu rounding
5382 mode. An insn should not be moved across this even if it only uses
5383 pseudo-regs because it might give an incorrectly rounded result.
5385 ?!? Unfortunately, marking all hard registers as live causes massive
5386 problems for the register allocator and marking all pseudos as live
5387 creates mountains of uninitialized variable warnings.
5389 So for now, just clear the memory set list and mark any regs
5390 we can find in ASM_OPERANDS as used. */
5391 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
5392 free_EXPR_LIST_list (&pbi->mem_set_list);
5394 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
5395 We can not just fall through here since then we would be confused
5396 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
5397 traditional asms unlike their normal usage. */
5398 if (code == ASM_OPERANDS)
5402 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
5403 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
5409 if (cond != NULL_RTX)
5412 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
5414 cond = COND_EXEC_TEST (x);
5415 x = COND_EXEC_CODE (x);
5419 /* We _do_not_ want to scan operands of phi nodes. Operands of
5420 a phi function are evaluated only when control reaches this
5421 block along a particular edge. Therefore, regs that appear
5422 as arguments to phi should not be added to the global live at
5430 /* Recursively scan the operands of this expression. */
5433 register const char *fmt = GET_RTX_FORMAT (code);
5436 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5440 /* Tail recursive case: save a function call level. */
5446 mark_used_regs (pbi, XEXP (x, i), cond, insn);
5448 else if (fmt[i] == 'E')
5451 for (j = 0; j < XVECLEN (x, i); j++)
5452 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
5461 try_pre_increment_1 (pbi, insn)
5462 struct propagate_block_info *pbi;
5465 /* Find the next use of this reg. If in same basic block,
5466 make it do pre-increment or pre-decrement if appropriate. */
5467 rtx x = single_set (insn);
5468 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
5469 * INTVAL (XEXP (SET_SRC (x), 1)));
5470 int regno = REGNO (SET_DEST (x));
5471 rtx y = pbi->reg_next_use[regno];
5473 && BLOCK_NUM (y) == BLOCK_NUM (insn)
5474 /* Don't do this if the reg dies, or gets set in y; a standard addressing
5475 mode would be better. */
5476 && ! dead_or_set_p (y, SET_DEST (x))
5477 && try_pre_increment (y, SET_DEST (x), amount))
5479 /* We have found a suitable auto-increment
5480 and already changed insn Y to do it.
5481 So flush this increment-instruction. */
5482 PUT_CODE (insn, NOTE);
5483 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
5484 NOTE_SOURCE_FILE (insn) = 0;
5485 /* Count a reference to this reg for the increment
5486 insn we are deleting. When a reg is incremented.
5487 spilling it is worse, so we want to make that
5489 if (regno >= FIRST_PSEUDO_REGISTER)
5491 REG_N_REFS (regno) += (optimize_size ? 1
5492 : pbi->bb->loop_depth + 1);
5493 REG_N_SETS (regno)++;
5500 /* Try to change INSN so that it does pre-increment or pre-decrement
5501 addressing on register REG in order to add AMOUNT to REG.
5502 AMOUNT is negative for pre-decrement.
5503 Returns 1 if the change could be made.
5504 This checks all about the validity of the result of modifying INSN. */
5507 try_pre_increment (insn, reg, amount)
5509 HOST_WIDE_INT amount;
5513 /* Nonzero if we can try to make a pre-increment or pre-decrement.
5514 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
5516 /* Nonzero if we can try to make a post-increment or post-decrement.
5517 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
5518 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
5519 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
5522 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
5525 /* From the sign of increment, see which possibilities are conceivable
5526 on this target machine. */
5527 if (HAVE_PRE_INCREMENT && amount > 0)
5529 if (HAVE_POST_INCREMENT && amount > 0)
5532 if (HAVE_PRE_DECREMENT && amount < 0)
5534 if (HAVE_POST_DECREMENT && amount < 0)
5537 if (! (pre_ok || post_ok))
5540 /* It is not safe to add a side effect to a jump insn
5541 because if the incremented register is spilled and must be reloaded
5542 there would be no way to store the incremented value back in memory. */
5544 if (GET_CODE (insn) == JUMP_INSN)
5549 use = find_use_as_address (PATTERN (insn), reg, 0);
5550 if (post_ok && (use == 0 || use == (rtx) 1))
5552 use = find_use_as_address (PATTERN (insn), reg, -amount);
5556 if (use == 0 || use == (rtx) 1)
5559 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
5562 /* See if this combination of instruction and addressing mode exists. */
5563 if (! validate_change (insn, &XEXP (use, 0),
5564 gen_rtx_fmt_e (amount > 0
5565 ? (do_post ? POST_INC : PRE_INC)
5566 : (do_post ? POST_DEC : PRE_DEC),
5570 /* Record that this insn now has an implicit side effect on X. */
5571 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
5575 #endif /* AUTO_INC_DEC */
5577 /* Find the place in the rtx X where REG is used as a memory address.
5578 Return the MEM rtx that so uses it.
5579 If PLUSCONST is nonzero, search instead for a memory address equivalent to
5580 (plus REG (const_int PLUSCONST)).
5582 If such an address does not appear, return 0.
5583 If REG appears more than once, or is used other than in such an address,
5587 find_use_as_address (x, reg, plusconst)
5590 HOST_WIDE_INT plusconst;
5592 enum rtx_code code = GET_CODE (x);
5593 const char *fmt = GET_RTX_FORMAT (code);
5595 register rtx value = 0;
5598 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
5601 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
5602 && XEXP (XEXP (x, 0), 0) == reg
5603 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
5604 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
5607 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
5609 /* If REG occurs inside a MEM used in a bit-field reference,
5610 that is unacceptable. */
5611 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
5612 return (rtx) (HOST_WIDE_INT) 1;
5616 return (rtx) (HOST_WIDE_INT) 1;
5618 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5622 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
5626 return (rtx) (HOST_WIDE_INT) 1;
5628 else if (fmt[i] == 'E')
5631 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
5633 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
5637 return (rtx) (HOST_WIDE_INT) 1;
5645 /* Write information about registers and basic blocks into FILE.
5646 This is part of making a debugging dump. */
5649 dump_regset (r, outf)
5656 fputs (" (nil)", outf);
5660 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
5662 fprintf (outf, " %d", i);
5663 if (i < FIRST_PSEUDO_REGISTER)
5664 fprintf (outf, " [%s]",
5673 dump_regset (r, stderr);
5674 putc ('\n', stderr);
5678 dump_flow_info (file)
5682 static const char * const reg_class_names[] = REG_CLASS_NAMES;
5684 fprintf (file, "%d registers.\n", max_regno);
5685 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
5688 enum reg_class class, altclass;
5689 fprintf (file, "\nRegister %d used %d times across %d insns",
5690 i, REG_N_REFS (i), REG_LIVE_LENGTH (i));
5691 if (REG_BASIC_BLOCK (i) >= 0)
5692 fprintf (file, " in block %d", REG_BASIC_BLOCK (i));
5694 fprintf (file, "; set %d time%s", REG_N_SETS (i),
5695 (REG_N_SETS (i) == 1) ? "" : "s");
5696 if (REG_USERVAR_P (regno_reg_rtx[i]))
5697 fprintf (file, "; user var");
5698 if (REG_N_DEATHS (i) != 1)
5699 fprintf (file, "; dies in %d places", REG_N_DEATHS (i));
5700 if (REG_N_CALLS_CROSSED (i) == 1)
5701 fprintf (file, "; crosses 1 call");
5702 else if (REG_N_CALLS_CROSSED (i))
5703 fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i));
5704 if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
5705 fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
5706 class = reg_preferred_class (i);
5707 altclass = reg_alternate_class (i);
5708 if (class != GENERAL_REGS || altclass != ALL_REGS)
5710 if (altclass == ALL_REGS || class == ALL_REGS)
5711 fprintf (file, "; pref %s", reg_class_names[(int) class]);
5712 else if (altclass == NO_REGS)
5713 fprintf (file, "; %s or none", reg_class_names[(int) class]);
5715 fprintf (file, "; pref %s, else %s",
5716 reg_class_names[(int) class],
5717 reg_class_names[(int) altclass]);
5719 if (REGNO_POINTER_FLAG (i))
5720 fprintf (file, "; pointer");
5721 fprintf (file, ".\n");
5724 fprintf (file, "\n%d basic blocks, %d edges.\n", n_basic_blocks, n_edges);
5725 for (i = 0; i < n_basic_blocks; i++)
5727 register basic_block bb = BASIC_BLOCK (i);
5730 fprintf (file, "\nBasic block %d: first insn %d, last %d, loop_depth %d, count %d.\n",
5731 i, INSN_UID (bb->head), INSN_UID (bb->end), bb->loop_depth, bb->count);
5733 fprintf (file, "Predecessors: ");
5734 for (e = bb->pred; e ; e = e->pred_next)
5735 dump_edge_info (file, e, 0);
5737 fprintf (file, "\nSuccessors: ");
5738 for (e = bb->succ; e ; e = e->succ_next)
5739 dump_edge_info (file, e, 1);
5741 fprintf (file, "\nRegisters live at start:");
5742 dump_regset (bb->global_live_at_start, file);
5744 fprintf (file, "\nRegisters live at end:");
5745 dump_regset (bb->global_live_at_end, file);
5756 dump_flow_info (stderr);
5760 dump_edge_info (file, e, do_succ)
5765 basic_block side = (do_succ ? e->dest : e->src);
5767 if (side == ENTRY_BLOCK_PTR)
5768 fputs (" ENTRY", file);
5769 else if (side == EXIT_BLOCK_PTR)
5770 fputs (" EXIT", file);
5772 fprintf (file, " %d", side->index);
5775 fprintf (file, " count:%d", e->count);
5779 static const char * const bitnames[] = {
5780 "fallthru", "crit", "ab", "abcall", "eh", "fake"
5783 int i, flags = e->flags;
5787 for (i = 0; flags; i++)
5788 if (flags & (1 << i))
5794 if (i < (int)(sizeof (bitnames) / sizeof (*bitnames)))
5795 fputs (bitnames[i], file);
5797 fprintf (file, "%d", i);
5805 /* Print out one basic block with live information at start and end. */
5815 fprintf (outf, ";; Basic block %d, loop depth %d, count %d",
5816 bb->index, bb->loop_depth, bb->count);
5817 if (bb->eh_beg != -1 || bb->eh_end != -1)
5818 fprintf (outf, ", eh regions %d/%d", bb->eh_beg, bb->eh_end);
5821 fputs (";; Predecessors: ", outf);
5822 for (e = bb->pred; e ; e = e->pred_next)
5823 dump_edge_info (outf, e, 0);
5826 fputs (";; Registers live at start:", outf);
5827 dump_regset (bb->global_live_at_start, outf);
5830 for (insn = bb->head, last = NEXT_INSN (bb->end);
5832 insn = NEXT_INSN (insn))
5833 print_rtl_single (outf, insn);
5835 fputs (";; Registers live at end:", outf);
5836 dump_regset (bb->global_live_at_end, outf);
5839 fputs (";; Successors: ", outf);
5840 for (e = bb->succ; e; e = e->succ_next)
5841 dump_edge_info (outf, e, 1);
5849 dump_bb (bb, stderr);
5856 dump_bb (BASIC_BLOCK(n), stderr);
5859 /* Like print_rtl, but also print out live information for the start of each
5863 print_rtl_with_bb (outf, rtx_first)
5867 register rtx tmp_rtx;
5870 fprintf (outf, "(nil)\n");
5874 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
5875 int max_uid = get_max_uid ();
5876 basic_block *start = (basic_block *)
5877 xcalloc (max_uid, sizeof (basic_block));
5878 basic_block *end = (basic_block *)
5879 xcalloc (max_uid, sizeof (basic_block));
5880 enum bb_state *in_bb_p = (enum bb_state *)
5881 xcalloc (max_uid, sizeof (enum bb_state));
5883 for (i = n_basic_blocks - 1; i >= 0; i--)
5885 basic_block bb = BASIC_BLOCK (i);
5888 start[INSN_UID (bb->head)] = bb;
5889 end[INSN_UID (bb->end)] = bb;
5890 for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x))
5892 enum bb_state state = IN_MULTIPLE_BB;
5893 if (in_bb_p[INSN_UID(x)] == NOT_IN_BB)
5895 in_bb_p[INSN_UID(x)] = state;
5902 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
5907 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
5909 fprintf (outf, ";; Start of basic block %d, registers live:",
5911 dump_regset (bb->global_live_at_start, outf);
5915 if (in_bb_p[INSN_UID(tmp_rtx)] == NOT_IN_BB
5916 && GET_CODE (tmp_rtx) != NOTE
5917 && GET_CODE (tmp_rtx) != BARRIER)
5918 fprintf (outf, ";; Insn is not within a basic block\n");
5919 else if (in_bb_p[INSN_UID(tmp_rtx)] == IN_MULTIPLE_BB)
5920 fprintf (outf, ";; Insn is in multiple basic blocks\n");
5922 did_output = print_rtl_single (outf, tmp_rtx);
5924 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
5926 fprintf (outf, ";; End of basic block %d, registers live:\n",
5928 dump_regset (bb->global_live_at_end, outf);
5941 if (current_function_epilogue_delay_list != 0)
5943 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
5944 for (tmp_rtx = current_function_epilogue_delay_list; tmp_rtx != 0;
5945 tmp_rtx = XEXP (tmp_rtx, 1))
5946 print_rtl_single (outf, XEXP (tmp_rtx, 0));
5950 /* Compute dominator relationships using new flow graph structures. */
5952 compute_flow_dominators (dominators, post_dominators)
5953 sbitmap *dominators;
5954 sbitmap *post_dominators;
5957 sbitmap *temp_bitmap;
5959 basic_block *worklist, *workend, *qin, *qout;
5962 /* Allocate a worklist array/queue. Entries are only added to the
5963 list if they were not already on the list. So the size is
5964 bounded by the number of basic blocks. */
5965 worklist = (basic_block *) xmalloc (sizeof (basic_block) * n_basic_blocks);
5966 workend = &worklist[n_basic_blocks];
5968 temp_bitmap = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
5969 sbitmap_vector_zero (temp_bitmap, n_basic_blocks);
5973 /* The optimistic setting of dominators requires us to put every
5974 block on the work list initially. */
5975 qin = qout = worklist;
5976 for (bb = 0; bb < n_basic_blocks; bb++)
5978 *qin++ = BASIC_BLOCK (bb);
5979 BASIC_BLOCK (bb)->aux = BASIC_BLOCK (bb);
5981 qlen = n_basic_blocks;
5984 /* We want a maximal solution, so initially assume everything dominates
5986 sbitmap_vector_ones (dominators, n_basic_blocks);
5988 /* Mark successors of the entry block so we can identify them below. */
5989 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
5990 e->dest->aux = ENTRY_BLOCK_PTR;
5992 /* Iterate until the worklist is empty. */
5995 /* Take the first entry off the worklist. */
5996 basic_block b = *qout++;
5997 if (qout >= workend)
6003 /* Compute the intersection of the dominators of all the
6006 If one of the predecessor blocks is the ENTRY block, then the
6007 intersection of the dominators of the predecessor blocks is
6008 defined as the null set. We can identify such blocks by the
6009 special value in the AUX field in the block structure. */
6010 if (b->aux == ENTRY_BLOCK_PTR)
6012 /* Do not clear the aux field for blocks which are
6013 successors of the ENTRY block. That way we we never
6014 add them to the worklist again.
6016 The intersect of dominators of the preds of this block is
6017 defined as the null set. */
6018 sbitmap_zero (temp_bitmap[bb]);
6022 /* Clear the aux field of this block so it can be added to
6023 the worklist again if necessary. */
6025 sbitmap_intersection_of_preds (temp_bitmap[bb], dominators, bb);
6028 /* Make sure each block always dominates itself. */
6029 SET_BIT (temp_bitmap[bb], bb);
6031 /* If the out state of this block changed, then we need to
6032 add the successors of this block to the worklist if they
6033 are not already on the worklist. */
6034 if (sbitmap_a_and_b (dominators[bb], dominators[bb], temp_bitmap[bb]))
6036 for (e = b->succ; e; e = e->succ_next)
6038 if (!e->dest->aux && e->dest != EXIT_BLOCK_PTR)
6052 if (post_dominators)
6054 /* The optimistic setting of dominators requires us to put every
6055 block on the work list initially. */
6056 qin = qout = worklist;
6057 for (bb = 0; bb < n_basic_blocks; bb++)
6059 *qin++ = BASIC_BLOCK (bb);
6060 BASIC_BLOCK (bb)->aux = BASIC_BLOCK (bb);
6062 qlen = n_basic_blocks;
6065 /* We want a maximal solution, so initially assume everything post
6066 dominates everything else. */
6067 sbitmap_vector_ones (post_dominators, n_basic_blocks);
6069 /* Mark predecessors of the exit block so we can identify them below. */
6070 for (e = EXIT_BLOCK_PTR->pred; e; e = e->pred_next)
6071 e->src->aux = EXIT_BLOCK_PTR;
6073 /* Iterate until the worklist is empty. */
6076 /* Take the first entry off the worklist. */
6077 basic_block b = *qout++;
6078 if (qout >= workend)
6084 /* Compute the intersection of the post dominators of all the
6087 If one of the successor blocks is the EXIT block, then the
6088 intersection of the dominators of the successor blocks is
6089 defined as the null set. We can identify such blocks by the
6090 special value in the AUX field in the block structure. */
6091 if (b->aux == EXIT_BLOCK_PTR)
6093 /* Do not clear the aux field for blocks which are
6094 predecessors of the EXIT block. That way we we never
6095 add them to the worklist again.
6097 The intersect of dominators of the succs of this block is
6098 defined as the null set. */
6099 sbitmap_zero (temp_bitmap[bb]);
6103 /* Clear the aux field of this block so it can be added to
6104 the worklist again if necessary. */
6106 sbitmap_intersection_of_succs (temp_bitmap[bb],
6107 post_dominators, bb);
6110 /* Make sure each block always post dominates itself. */
6111 SET_BIT (temp_bitmap[bb], bb);
6113 /* If the out state of this block changed, then we need to
6114 add the successors of this block to the worklist if they
6115 are not already on the worklist. */
6116 if (sbitmap_a_and_b (post_dominators[bb],
6117 post_dominators[bb],
6120 for (e = b->pred; e; e = e->pred_next)
6122 if (!e->src->aux && e->src != ENTRY_BLOCK_PTR)
6140 /* Given DOMINATORS, compute the immediate dominators into IDOM. */
6143 compute_immediate_dominators (idom, dominators)
6145 sbitmap *dominators;
6150 tmp = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
6152 /* Begin with tmp(n) = dom(n) - { n }. */
6153 for (b = n_basic_blocks; --b >= 0; )
6155 sbitmap_copy (tmp[b], dominators[b]);
6156 RESET_BIT (tmp[b], b);
6159 /* Subtract out all of our dominator's dominators. */
6160 for (b = n_basic_blocks; --b >= 0; )
6162 sbitmap tmp_b = tmp[b];
6165 for (s = n_basic_blocks; --s >= 0; )
6166 if (TEST_BIT (tmp_b, s))
6167 sbitmap_difference (tmp_b, tmp_b, tmp[s]);
6170 /* Find the one bit set in the bitmap and put it in the output array. */
6171 for (b = n_basic_blocks; --b >= 0; )
6174 EXECUTE_IF_SET_IN_SBITMAP (tmp[b], 0, t, { idom[b] = t; });
6177 sbitmap_vector_free (tmp);
6180 /* Recompute register set/reference counts immediately prior to register
6183 This avoids problems with set/reference counts changing to/from values
6184 which have special meanings to the register allocators.
6186 Additionally, the reference counts are the primary component used by the
6187 register allocators to prioritize pseudos for allocation to hard regs.
6188 More accurate reference counts generally lead to better register allocation.
6190 F is the first insn to be scanned.
6192 LOOP_STEP denotes how much loop_depth should be incremented per
6193 loop nesting level in order to increase the ref count more for
6194 references in a loop.
6196 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
6197 possibly other information which is used by the register allocators. */
6200 recompute_reg_usage (f, loop_step)
6201 rtx f ATTRIBUTE_UNUSED;
6202 int loop_step ATTRIBUTE_UNUSED;
6204 allocate_reg_life_data ();
6205 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
6208 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
6209 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
6210 of the number of registers that died. */
6213 count_or_remove_death_notes (blocks, kill)
6219 for (i = n_basic_blocks - 1; i >= 0; --i)
6224 if (blocks && ! TEST_BIT (blocks, i))
6227 bb = BASIC_BLOCK (i);
6229 for (insn = bb->head; ; insn = NEXT_INSN (insn))
6231 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
6233 rtx *pprev = ®_NOTES (insn);
6238 switch (REG_NOTE_KIND (link))
6241 if (GET_CODE (XEXP (link, 0)) == REG)
6243 rtx reg = XEXP (link, 0);
6246 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
6249 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
6257 rtx next = XEXP (link, 1);
6258 free_EXPR_LIST_node (link);
6259 *pprev = link = next;
6265 pprev = &XEXP (link, 1);
6272 if (insn == bb->end)
6280 /* Record INSN's block as BB. */
6283 set_block_for_insn (insn, bb)
6287 size_t uid = INSN_UID (insn);
6288 if (uid >= basic_block_for_insn->num_elements)
6292 /* Add one-eighth the size so we don't keep calling xrealloc. */
6293 new_size = uid + (uid + 7) / 8;
6295 VARRAY_GROW (basic_block_for_insn, new_size);
6297 VARRAY_BB (basic_block_for_insn, uid) = bb;
6300 /* Record INSN's block number as BB. */
6301 /* ??? This has got to go. */
6304 set_block_num (insn, bb)
6308 set_block_for_insn (insn, BASIC_BLOCK (bb));
6311 /* Verify the CFG consistency. This function check some CFG invariants and
6312 aborts when something is wrong. Hope that this function will help to
6313 convert many optimization passes to preserve CFG consistent.
6315 Currently it does following checks:
6317 - test head/end pointers
6318 - overlapping of basic blocks
6319 - edge list corectness
6320 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
6321 - tails of basic blocks (ensure that boundary is necesary)
6322 - scans body of the basic block for JUMP_INSN, CODE_LABEL
6323 and NOTE_INSN_BASIC_BLOCK
6324 - check that all insns are in the basic blocks
6325 (except the switch handling code, barriers and notes)
6326 - check that all returns are followed by barriers
6328 In future it can be extended check a lot of other stuff as well
6329 (reachability of basic blocks, life information, etc. etc.). */
6334 const int max_uid = get_max_uid ();
6335 const rtx rtx_first = get_insns ();
6336 basic_block *bb_info;
6338 int i, last_bb_num_seen, num_bb_notes, err = 0;
6340 bb_info = (basic_block *) xcalloc (max_uid, sizeof (basic_block));
6342 /* First pass check head/end pointers and set bb_info array used by
6344 for (i = n_basic_blocks - 1; i >= 0; i--)
6346 basic_block bb = BASIC_BLOCK (i);
6348 /* Check the head pointer and make sure that it is pointing into
6350 for (x = rtx_first; x != NULL_RTX; x = NEXT_INSN (x))
6355 error ("Head insn %d for block %d not found in the insn stream.",
6356 INSN_UID (bb->head), bb->index);
6360 /* Check the end pointer and make sure that it is pointing into
6362 for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x))
6364 if (bb_info[INSN_UID (x)] != NULL)
6366 error ("Insn %d is in multiple basic blocks (%d and %d)",
6367 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
6370 bb_info[INSN_UID (x)] = bb;
6377 error ("End insn %d for block %d not found in the insn stream.",
6378 INSN_UID (bb->end), bb->index);
6383 /* Now check the basic blocks (boundaries etc.) */
6384 for (i = n_basic_blocks - 1; i >= 0; i--)
6386 basic_block bb = BASIC_BLOCK (i);
6387 /* Check corectness of edge lists */
6395 fprintf (stderr, "verify_flow_info: Basic block %d succ edge is corrupted\n",
6397 fprintf (stderr, "Predecessor: ");
6398 dump_edge_info (stderr, e, 0);
6399 fprintf (stderr, "\nSuccessor: ");
6400 dump_edge_info (stderr, e, 1);
6404 if (e->dest != EXIT_BLOCK_PTR)
6406 edge e2 = e->dest->pred;
6407 while (e2 && e2 != e)
6411 error ("Basic block %i edge lists are corrupted", bb->index);
6423 error ("Basic block %d pred edge is corrupted", bb->index);
6424 fputs ("Predecessor: ", stderr);
6425 dump_edge_info (stderr, e, 0);
6426 fputs ("\nSuccessor: ", stderr);
6427 dump_edge_info (stderr, e, 1);
6428 fputc ('\n', stderr);
6431 if (e->src != ENTRY_BLOCK_PTR)
6433 edge e2 = e->src->succ;
6434 while (e2 && e2 != e)
6438 error ("Basic block %i edge lists are corrupted", bb->index);
6445 /* OK pointers are correct. Now check the header of basic
6446 block. It ought to contain optional CODE_LABEL followed
6447 by NOTE_BASIC_BLOCK. */
6449 if (GET_CODE (x) == CODE_LABEL)
6453 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
6459 if (GET_CODE (x) != NOTE
6460 || NOTE_LINE_NUMBER (x) != NOTE_INSN_BASIC_BLOCK
6461 || NOTE_BASIC_BLOCK (x) != bb)
6463 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d\n",
6470 /* Do checks for empty blocks here */
6477 if (GET_CODE (x) == NOTE
6478 && NOTE_LINE_NUMBER (x) == NOTE_INSN_BASIC_BLOCK)
6480 error ("NOTE_INSN_BASIC_BLOCK %d in the middle of basic block %d",
6481 INSN_UID (x), bb->index);
6488 if (GET_CODE (x) == JUMP_INSN
6489 || GET_CODE (x) == CODE_LABEL
6490 || GET_CODE (x) == BARRIER)
6492 error ("In basic block %d:", bb->index);
6493 fatal_insn ("Flow control insn inside a basic block", x);
6501 last_bb_num_seen = -1;
6506 if (GET_CODE (x) == NOTE
6507 && NOTE_LINE_NUMBER (x) == NOTE_INSN_BASIC_BLOCK)
6509 basic_block bb = NOTE_BASIC_BLOCK (x);
6511 if (bb->index != last_bb_num_seen + 1)
6512 fatal ("Basic blocks not numbered consecutively");
6513 last_bb_num_seen = bb->index;
6516 if (!bb_info[INSN_UID (x)])
6518 switch (GET_CODE (x))
6525 /* An addr_vec is placed outside any block block. */
6527 && GET_CODE (NEXT_INSN (x)) == JUMP_INSN
6528 && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
6529 || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
6534 /* But in any case, non-deletable labels can appear anywhere. */
6538 fatal_insn ("Insn outside basic block", x);
6542 if (GET_RTX_CLASS (GET_CODE (x)) == 'i'
6543 && GET_CODE (x) == JUMP_INSN
6544 && returnjump_p (x) && ! condjump_p (x)
6545 && ! (NEXT_INSN (x) && GET_CODE (NEXT_INSN (x)) == BARRIER))
6546 fatal_insn ("Return not followed by barrier", x);
6551 if (num_bb_notes != n_basic_blocks)
6552 fatal ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
6553 num_bb_notes, n_basic_blocks);
6562 /* Functions to access an edge list with a vector representation.
6563 Enough data is kept such that given an index number, the
6564 pred and succ that edge reprsents can be determined, or
6565 given a pred and a succ, it's index number can be returned.
6566 This allows algorithms which comsume a lot of memory to
6567 represent the normally full matrix of edge (pred,succ) with a
6568 single indexed vector, edge (EDGE_INDEX (pred, succ)), with no
6569 wasted space in the client code due to sparse flow graphs. */
6571 /* This functions initializes the edge list. Basically the entire
6572 flowgraph is processed, and all edges are assigned a number,
6573 and the data structure is filed in. */
6577 struct edge_list *elist;
6583 block_count = n_basic_blocks + 2; /* Include the entry and exit blocks. */
6587 /* Determine the number of edges in the flow graph by counting successor
6588 edges on each basic block. */
6589 for (x = 0; x < n_basic_blocks; x++)
6591 basic_block bb = BASIC_BLOCK (x);
6593 for (e = bb->succ; e; e = e->succ_next)
6596 /* Don't forget successors of the entry block. */
6597 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
6600 elist = (struct edge_list *) xmalloc (sizeof (struct edge_list));
6601 elist->num_blocks = block_count;
6602 elist->num_edges = num_edges;
6603 elist->index_to_edge = (edge *) xmalloc (sizeof (edge) * num_edges);
6607 /* Follow successors of the entry block, and register these edges. */
6608 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
6610 elist->index_to_edge[num_edges] = e;
6614 for (x = 0; x < n_basic_blocks; x++)
6616 basic_block bb = BASIC_BLOCK (x);
6618 /* Follow all successors of blocks, and register these edges. */
6619 for (e = bb->succ; e; e = e->succ_next)
6621 elist->index_to_edge[num_edges] = e;
6628 /* This function free's memory associated with an edge list. */
6630 free_edge_list (elist)
6631 struct edge_list *elist;
6635 free (elist->index_to_edge);
6640 /* This function provides debug output showing an edge list. */
6642 print_edge_list (f, elist)
6644 struct edge_list *elist;
6647 fprintf(f, "Compressed edge list, %d BBs + entry & exit, and %d edges\n",
6648 elist->num_blocks - 2, elist->num_edges);
6650 for (x = 0; x < elist->num_edges; x++)
6652 fprintf (f, " %-4d - edge(", x);
6653 if (INDEX_EDGE_PRED_BB (elist, x) == ENTRY_BLOCK_PTR)
6654 fprintf (f,"entry,");
6656 fprintf (f,"%d,", INDEX_EDGE_PRED_BB (elist, x)->index);
6658 if (INDEX_EDGE_SUCC_BB (elist, x) == EXIT_BLOCK_PTR)
6659 fprintf (f,"exit)\n");
6661 fprintf (f,"%d)\n", INDEX_EDGE_SUCC_BB (elist, x)->index);
6665 /* This function provides an internal consistancy check of an edge list,
6666 verifying that all edges are present, and that there are no
6669 verify_edge_list (f, elist)
6671 struct edge_list *elist;
6673 int x, pred, succ, index;
6676 for (x = 0; x < n_basic_blocks; x++)
6678 basic_block bb = BASIC_BLOCK (x);
6680 for (e = bb->succ; e; e = e->succ_next)
6682 pred = e->src->index;
6683 succ = e->dest->index;
6684 index = EDGE_INDEX (elist, e->src, e->dest);
6685 if (index == EDGE_INDEX_NO_EDGE)
6687 fprintf (f, "*p* No index for edge from %d to %d\n",pred, succ);
6690 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
6691 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
6692 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
6693 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
6694 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
6695 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
6698 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
6700 pred = e->src->index;
6701 succ = e->dest->index;
6702 index = EDGE_INDEX (elist, e->src, e->dest);
6703 if (index == EDGE_INDEX_NO_EDGE)
6705 fprintf (f, "*p* No index for edge from %d to %d\n",pred, succ);
6708 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
6709 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
6710 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
6711 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
6712 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
6713 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
6715 /* We've verified that all the edges are in the list, no lets make sure
6716 there are no spurious edges in the list. */
6718 for (pred = 0 ; pred < n_basic_blocks; pred++)
6719 for (succ = 0 ; succ < n_basic_blocks; succ++)
6721 basic_block p = BASIC_BLOCK (pred);
6722 basic_block s = BASIC_BLOCK (succ);
6726 for (e = p->succ; e; e = e->succ_next)
6732 for (e = s->pred; e; e = e->pred_next)
6738 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
6739 == EDGE_INDEX_NO_EDGE && found_edge != 0)
6740 fprintf (f, "*** Edge (%d, %d) appears to not have an index\n",
6742 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
6743 != EDGE_INDEX_NO_EDGE && found_edge == 0)
6744 fprintf (f, "*** Edge (%d, %d) has index %d, but there is no edge\n",
6745 pred, succ, EDGE_INDEX (elist, BASIC_BLOCK (pred),
6746 BASIC_BLOCK (succ)));
6748 for (succ = 0 ; succ < n_basic_blocks; succ++)
6750 basic_block p = ENTRY_BLOCK_PTR;
6751 basic_block s = BASIC_BLOCK (succ);
6755 for (e = p->succ; e; e = e->succ_next)
6761 for (e = s->pred; e; e = e->pred_next)
6767 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
6768 == EDGE_INDEX_NO_EDGE && found_edge != 0)
6769 fprintf (f, "*** Edge (entry, %d) appears to not have an index\n",
6771 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
6772 != EDGE_INDEX_NO_EDGE && found_edge == 0)
6773 fprintf (f, "*** Edge (entry, %d) has index %d, but no edge exists\n",
6774 succ, EDGE_INDEX (elist, ENTRY_BLOCK_PTR,
6775 BASIC_BLOCK (succ)));
6777 for (pred = 0 ; pred < n_basic_blocks; pred++)
6779 basic_block p = BASIC_BLOCK (pred);
6780 basic_block s = EXIT_BLOCK_PTR;
6784 for (e = p->succ; e; e = e->succ_next)
6790 for (e = s->pred; e; e = e->pred_next)
6796 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
6797 == EDGE_INDEX_NO_EDGE && found_edge != 0)
6798 fprintf (f, "*** Edge (%d, exit) appears to not have an index\n",
6800 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
6801 != EDGE_INDEX_NO_EDGE && found_edge == 0)
6802 fprintf (f, "*** Edge (%d, exit) has index %d, but no edge exists\n",
6803 pred, EDGE_INDEX (elist, BASIC_BLOCK (pred),
6808 /* This routine will determine what, if any, edge there is between
6809 a specified predecessor and successor. */
6812 find_edge_index (edge_list, pred, succ)
6813 struct edge_list *edge_list;
6814 basic_block pred, succ;
6817 for (x = 0; x < NUM_EDGES (edge_list); x++)
6819 if (INDEX_EDGE_PRED_BB (edge_list, x) == pred
6820 && INDEX_EDGE_SUCC_BB (edge_list, x) == succ)
6823 return (EDGE_INDEX_NO_EDGE);
6826 /* This function will remove an edge from the flow graph. */
6831 edge last_pred = NULL;
6832 edge last_succ = NULL;
6834 basic_block src, dest;
6837 for (tmp = src->succ; tmp && tmp != e; tmp = tmp->succ_next)
6843 last_succ->succ_next = e->succ_next;
6845 src->succ = e->succ_next;
6847 for (tmp = dest->pred; tmp && tmp != e; tmp = tmp->pred_next)
6853 last_pred->pred_next = e->pred_next;
6855 dest->pred = e->pred_next;
6861 /* This routine will remove any fake successor edges for a basic block.
6862 When the edge is removed, it is also removed from whatever predecessor
6865 remove_fake_successors (bb)
6869 for (e = bb->succ; e ; )
6873 if ((tmp->flags & EDGE_FAKE) == EDGE_FAKE)
6878 /* This routine will remove all fake edges from the flow graph. If
6879 we remove all fake successors, it will automatically remove all
6880 fake predecessors. */
6882 remove_fake_edges ()
6886 for (x = 0; x < n_basic_blocks; x++)
6887 remove_fake_successors (BASIC_BLOCK (x));
6889 /* We've handled all successors except the entry block's. */
6890 remove_fake_successors (ENTRY_BLOCK_PTR);
6893 /* This functions will add a fake edge between any block which has no
6894 successors, and the exit block. Some data flow equations require these
6897 add_noreturn_fake_exit_edges ()
6901 for (x = 0; x < n_basic_blocks; x++)
6902 if (BASIC_BLOCK (x)->succ == NULL)
6903 make_edge (NULL, BASIC_BLOCK (x), EXIT_BLOCK_PTR, EDGE_FAKE);
6906 /* Redirect an edge's successor from one block to another. */
6909 redirect_edge_succ (e, new_succ)
6911 basic_block new_succ;
6915 /* Disconnect the edge from the old successor block. */
6916 for (pe = &e->dest->pred; *pe != e ; pe = &(*pe)->pred_next)
6918 *pe = (*pe)->pred_next;
6920 /* Reconnect the edge to the new successor block. */
6921 e->pred_next = new_succ->pred;
6926 /* Redirect an edge's predecessor from one block to another. */
6929 redirect_edge_pred (e, new_pred)
6931 basic_block new_pred;
6935 /* Disconnect the edge from the old predecessor block. */
6936 for (pe = &e->src->succ; *pe != e ; pe = &(*pe)->succ_next)
6938 *pe = (*pe)->succ_next;
6940 /* Reconnect the edge to the new predecessor block. */
6941 e->succ_next = new_pred->succ;
6946 /* Dump the list of basic blocks in the bitmap NODES. */
6948 flow_nodes_print (str, nodes, file)
6950 const sbitmap nodes;
6955 fprintf (file, "%s { ", str);
6956 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {fprintf (file, "%d ", node);});
6957 fputs ("}\n", file);
6961 /* Dump the list of exiting edges in the array EDGES. */
6963 flow_exits_print (str, edges, num_edges, file)
6971 fprintf (file, "%s { ", str);
6972 for (i = 0; i < num_edges; i++)
6973 fprintf (file, "%d->%d ", edges[i]->src->index, edges[i]->dest->index);
6974 fputs ("}\n", file);
6978 /* Dump loop related CFG information. */
6980 flow_loops_cfg_dump (loops, file)
6981 const struct loops *loops;
6986 if (! loops->num || ! file || ! loops->cfg.dom)
6989 for (i = 0; i < n_basic_blocks; i++)
6993 fprintf (file, ";; %d succs { ", i);
6994 for (succ = BASIC_BLOCK (i)->succ; succ; succ = succ->succ_next)
6995 fprintf (file, "%d ", succ->dest->index);
6996 flow_nodes_print ("} dom", loops->cfg.dom[i], file);
7000 /* Dump the DFS node order. */
7001 if (loops->cfg.dfs_order)
7003 fputs (";; DFS order: ", file);
7004 for (i = 0; i < n_basic_blocks; i++)
7005 fprintf (file, "%d ", loops->cfg.dfs_order[i]);
7011 /* Return non-zero if the nodes of LOOP are a subset of OUTER. */
7013 flow_loop_nested_p (outer, loop)
7017 return sbitmap_a_subset_b_p (loop->nodes, outer->nodes);
7021 /* Dump the loop information specified by LOOPS to the stream FILE. */
7023 flow_loops_dump (loops, file, verbose)
7024 const struct loops *loops;
7031 num_loops = loops->num;
7032 if (! num_loops || ! file)
7035 fprintf (file, ";; %d loops found, %d levels\n",
7036 num_loops, loops->levels);
7038 for (i = 0; i < num_loops; i++)
7040 struct loop *loop = &loops->array[i];
7042 fprintf (file, ";; loop %d (%d to %d):\n;; header %d, latch %d, pre-header %d, depth %d, level %d, outer %ld\n",
7043 i, INSN_UID (loop->header->head), INSN_UID (loop->latch->end),
7044 loop->header->index, loop->latch->index,
7045 loop->pre_header ? loop->pre_header->index : -1,
7046 loop->depth, loop->level,
7047 (long) (loop->outer ? (loop->outer - loops->array) : -1));
7048 fprintf (file, ";; %d", loop->num_nodes);
7049 flow_nodes_print (" nodes", loop->nodes, file);
7050 fprintf (file, ";; %d", loop->num_exits);
7051 flow_exits_print (" exits", loop->exits, loop->num_exits, file);
7057 for (j = 0; j < i; j++)
7059 struct loop *oloop = &loops->array[j];
7061 if (loop->header == oloop->header)
7066 smaller = loop->num_nodes < oloop->num_nodes;
7068 /* If the union of LOOP and OLOOP is different than
7069 the larger of LOOP and OLOOP then LOOP and OLOOP
7070 must be disjoint. */
7071 disjoint = ! flow_loop_nested_p (smaller ? loop : oloop,
7072 smaller ? oloop : loop);
7073 fprintf (file, ";; loop header %d shared by loops %d, %d %s\n",
7074 loop->header->index, i, j,
7075 disjoint ? "disjoint" : "nested");
7082 /* Print diagnostics to compare our concept of a loop with
7083 what the loop notes say. */
7084 if (GET_CODE (PREV_INSN (loop->first->head)) != NOTE
7085 || NOTE_LINE_NUMBER (PREV_INSN (loop->first->head))
7086 != NOTE_INSN_LOOP_BEG)
7087 fprintf (file, ";; No NOTE_INSN_LOOP_BEG at %d\n",
7088 INSN_UID (PREV_INSN (loop->first->head)));
7089 if (GET_CODE (NEXT_INSN (loop->last->end)) != NOTE
7090 || NOTE_LINE_NUMBER (NEXT_INSN (loop->last->end))
7091 != NOTE_INSN_LOOP_END)
7092 fprintf (file, ";; No NOTE_INSN_LOOP_END at %d\n",
7093 INSN_UID (NEXT_INSN (loop->last->end)));
7098 flow_loops_cfg_dump (loops, file);
7102 /* Free all the memory allocated for LOOPS. */
7104 flow_loops_free (loops)
7105 struct loops *loops;
7114 /* Free the loop descriptors. */
7115 for (i = 0; i < loops->num; i++)
7117 struct loop *loop = &loops->array[i];
7120 sbitmap_free (loop->nodes);
7124 free (loops->array);
7125 loops->array = NULL;
7128 sbitmap_vector_free (loops->cfg.dom);
7129 if (loops->cfg.dfs_order)
7130 free (loops->cfg.dfs_order);
7132 sbitmap_free (loops->shared_headers);
7137 /* Find the exits from the loop using the bitmap of loop nodes NODES
7138 and store in EXITS array. Return the number of exits from the
7141 flow_loop_exits_find (nodes, exits)
7142 const sbitmap nodes;
7151 /* Check all nodes within the loop to see if there are any
7152 successors not in the loop. Note that a node may have multiple
7155 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
7156 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
7158 basic_block dest = e->dest;
7160 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
7168 *exits = (edge *) xmalloc (num_exits * sizeof (edge *));
7170 /* Store all exiting edges into an array. */
7172 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
7173 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
7175 basic_block dest = e->dest;
7177 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
7178 (*exits)[num_exits++] = e;
7186 /* Find the nodes contained within the loop with header HEADER and
7187 latch LATCH and store in NODES. Return the number of nodes within
7190 flow_loop_nodes_find (header, latch, nodes)
7199 stack = (basic_block *) xmalloc (n_basic_blocks * sizeof (basic_block));
7202 /* Start with only the loop header in the set of loop nodes. */
7203 sbitmap_zero (nodes);
7204 SET_BIT (nodes, header->index);
7206 header->loop_depth++;
7208 /* Push the loop latch on to the stack. */
7209 if (! TEST_BIT (nodes, latch->index))
7211 SET_BIT (nodes, latch->index);
7212 latch->loop_depth++;
7214 stack[sp++] = latch;
7223 for (e = node->pred; e; e = e->pred_next)
7225 basic_block ancestor = e->src;
7227 /* If each ancestor not marked as part of loop, add to set of
7228 loop nodes and push on to stack. */
7229 if (ancestor != ENTRY_BLOCK_PTR
7230 && ! TEST_BIT (nodes, ancestor->index))
7232 SET_BIT (nodes, ancestor->index);
7233 ancestor->loop_depth++;
7235 stack[sp++] = ancestor;
7244 /* Compute the depth first search order and store in the array
7245 DFS_ORDER, marking the nodes visited in VISITED. Returns the
7246 number of nodes visited. */
7248 flow_depth_first_order_compute (dfs_order)
7257 /* Allocate stack for back-tracking up CFG. */
7258 stack = (edge *) xmalloc (n_basic_blocks * sizeof (edge));
7261 /* Allocate bitmap to track nodes that have been visited. */
7262 visited = sbitmap_alloc (n_basic_blocks);
7264 /* None of the nodes in the CFG have been visited yet. */
7265 sbitmap_zero (visited);
7267 /* Start with the first successor edge from the entry block. */
7268 e = ENTRY_BLOCK_PTR->succ;
7271 basic_block src = e->src;
7272 basic_block dest = e->dest;
7274 /* Mark that we have visited this node. */
7275 if (src != ENTRY_BLOCK_PTR)
7276 SET_BIT (visited, src->index);
7278 /* If this node has not been visited before, push the current
7279 edge on to the stack and proceed with the first successor
7280 edge of this node. */
7281 if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index)
7289 if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index)
7292 /* DEST has no successors (for example, a non-returning
7293 function is called) so do not push the current edge
7294 but carry on with its next successor. */
7295 dfs_order[dest->index] = n_basic_blocks - ++dfsnum;
7296 SET_BIT (visited, dest->index);
7299 while (! e->succ_next && src != ENTRY_BLOCK_PTR)
7301 dfs_order[src->index] = n_basic_blocks - ++dfsnum;
7303 /* Pop edge off stack. */
7311 sbitmap_free (visited);
7313 /* The number of nodes visited should not be greater than
7315 if (dfsnum > n_basic_blocks)
7318 /* There are some nodes left in the CFG that are unreachable. */
7319 if (dfsnum < n_basic_blocks)
7325 /* Return the block for the pre-header of the loop with header
7326 HEADER where DOM specifies the dominator information. Return NULL if
7327 there is no pre-header. */
7329 flow_loop_pre_header_find (header, dom)
7333 basic_block pre_header;
7336 /* If block p is a predecessor of the header and is the only block
7337 that the header does not dominate, then it is the pre-header. */
7339 for (e = header->pred; e; e = e->pred_next)
7341 basic_block node = e->src;
7343 if (node != ENTRY_BLOCK_PTR
7344 && ! TEST_BIT (dom[node->index], header->index))
7346 if (pre_header == NULL)
7350 /* There are multiple edges into the header from outside
7351 the loop so there is no pre-header block. */
7361 /* Add LOOP to the loop hierarchy tree where PREVLOOP was the loop
7362 previously added. The insertion algorithm assumes that the loops
7363 are added in the order found by a depth first search of the CFG. */
7365 flow_loop_tree_node_add (prevloop, loop)
7366 struct loop *prevloop;
7370 if (flow_loop_nested_p (prevloop, loop))
7372 prevloop->inner = loop;
7373 loop->outer = prevloop;
7377 while (prevloop->outer)
7379 if (flow_loop_nested_p (prevloop->outer, loop))
7381 prevloop->next = loop;
7382 loop->outer = prevloop->outer;
7385 prevloop = prevloop->outer;
7388 prevloop->next = loop;
7393 /* Build the loop hierarchy tree for LOOPS. */
7395 flow_loops_tree_build (loops)
7396 struct loops *loops;
7401 num_loops = loops->num;
7405 /* Root the loop hierarchy tree with the first loop found.
7406 Since we used a depth first search this should be the
7408 loops->tree = &loops->array[0];
7409 loops->tree->outer = loops->tree->inner = loops->tree->next = NULL;
7411 /* Add the remaining loops to the tree. */
7412 for (i = 1; i < num_loops; i++)
7413 flow_loop_tree_node_add (&loops->array[i - 1], &loops->array[i]);
7417 /* Helper function to compute loop nesting depth and enclosed loop level
7418 for the natural loop specified by LOOP at the loop depth DEPTH.
7419 Returns the loop level. */
7421 flow_loop_level_compute (loop, depth)
7431 /* Traverse loop tree assigning depth and computing level as the
7432 maximum level of all the inner loops of this loop. The loop
7433 level is equivalent to the height of the loop in the loop tree
7434 and corresponds to the number of enclosed loop levels (including
7436 for (inner = loop->inner; inner; inner = inner->next)
7440 ilevel = flow_loop_level_compute (inner, depth + 1) + 1;
7445 loop->level = level;
7446 loop->depth = depth;
7451 /* Compute the loop nesting depth and enclosed loop level for the loop
7452 hierarchy tree specfied by LOOPS. Return the maximum enclosed loop
7456 flow_loops_level_compute (loops)
7457 struct loops *loops;
7463 /* Traverse all the outer level loops. */
7464 for (loop = loops->tree; loop; loop = loop->next)
7466 level = flow_loop_level_compute (loop, 1);
7474 /* Find all the natural loops in the function and save in LOOPS structure
7475 and recalculate loop_depth information in basic block structures.
7476 Return the number of natural loops found. */
7479 flow_loops_find (loops)
7480 struct loops *loops;
7491 loops->array = NULL;
7495 /* Taking care of this degenerate case makes the rest of
7496 this code simpler. */
7497 if (n_basic_blocks == 0)
7500 /* Compute the dominators. */
7501 dom = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
7502 compute_flow_dominators (dom, NULL);
7504 /* Count the number of loop edges (back edges). This should be the
7505 same as the number of natural loops. Also clear the loop_depth
7506 and as we work from inner->outer in a loop nest we call
7507 find_loop_nodes_find which will increment loop_depth for nodes
7508 within the current loop, which happens to enclose inner loops. */
7511 for (b = 0; b < n_basic_blocks; b++)
7513 BASIC_BLOCK (b)->loop_depth = 0;
7514 for (e = BASIC_BLOCK (b)->pred; e; e = e->pred_next)
7516 basic_block latch = e->src;
7518 /* Look for back edges where a predecessor is dominated
7519 by this block. A natural loop has a single entry
7520 node (header) that dominates all the nodes in the
7521 loop. It also has single back edge to the header
7522 from a latch node. Note that multiple natural loops
7523 may share the same header. */
7524 if (latch != ENTRY_BLOCK_PTR && TEST_BIT (dom[latch->index], b))
7531 /* Compute depth first search order of the CFG so that outer
7532 natural loops will be found before inner natural loops. */
7533 dfs_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
7534 flow_depth_first_order_compute (dfs_order);
7536 /* Allocate loop structures. */
7538 = (struct loop *) xcalloc (num_loops, sizeof (struct loop));
7540 headers = sbitmap_alloc (n_basic_blocks);
7541 sbitmap_zero (headers);
7543 loops->shared_headers = sbitmap_alloc (n_basic_blocks);
7544 sbitmap_zero (loops->shared_headers);
7546 /* Find and record information about all the natural loops
7549 for (b = 0; b < n_basic_blocks; b++)
7553 /* Search the nodes of the CFG in DFS order that we can find
7554 outer loops first. */
7555 header = BASIC_BLOCK (dfs_order[b]);
7557 /* Look for all the possible latch blocks for this header. */
7558 for (e = header->pred; e; e = e->pred_next)
7560 basic_block latch = e->src;
7562 /* Look for back edges where a predecessor is dominated
7563 by this block. A natural loop has a single entry
7564 node (header) that dominates all the nodes in the
7565 loop. It also has single back edge to the header
7566 from a latch node. Note that multiple natural loops
7567 may share the same header. */
7568 if (latch != ENTRY_BLOCK_PTR
7569 && TEST_BIT (dom[latch->index], header->index))
7573 loop = loops->array + num_loops;
7575 loop->header = header;
7576 loop->latch = latch;
7578 /* Keep track of blocks that are loop headers so
7579 that we can tell which loops should be merged. */
7580 if (TEST_BIT (headers, header->index))
7581 SET_BIT (loops->shared_headers, header->index);
7582 SET_BIT (headers, header->index);
7584 /* Find nodes contained within the loop. */
7585 loop->nodes = sbitmap_alloc (n_basic_blocks);
7587 = flow_loop_nodes_find (header, latch, loop->nodes);
7589 /* Compute first and last blocks within the loop.
7590 These are often the same as the loop header and
7591 loop latch respectively, but this is not always
7594 = BASIC_BLOCK (sbitmap_first_set_bit (loop->nodes));
7596 = BASIC_BLOCK (sbitmap_last_set_bit (loop->nodes));
7598 /* Find edges which exit the loop. Note that a node
7599 may have several exit edges. */
7601 = flow_loop_exits_find (loop->nodes, &loop->exits);
7603 /* Look to see if the loop has a pre-header node. */
7605 = flow_loop_pre_header_find (header, dom);
7612 /* Natural loops with shared headers may either be disjoint or
7613 nested. Disjoint loops with shared headers cannot be inner
7614 loops and should be merged. For now just mark loops that share
7616 for (i = 0; i < num_loops; i++)
7617 if (TEST_BIT (loops->shared_headers, loops->array[i].header->index))
7618 loops->array[i].shared = 1;
7620 sbitmap_free (headers);
7623 loops->num = num_loops;
7625 /* Save CFG derived information to avoid recomputing it. */
7626 loops->cfg.dom = dom;
7627 loops->cfg.dfs_order = dfs_order;
7629 /* Build the loop hierarchy tree. */
7630 flow_loops_tree_build (loops);
7632 /* Assign the loop nesting depth and enclosed loop level for each
7634 loops->levels = flow_loops_level_compute (loops);
7640 /* Return non-zero if edge E enters header of LOOP from outside of LOOP. */
7643 flow_loop_outside_edge_p (loop, e)
7644 const struct loop *loop;
7647 if (e->dest != loop->header)
7649 return (e->src == ENTRY_BLOCK_PTR)
7650 || ! TEST_BIT (loop->nodes, e->src->index);
7654 /* Clear LOG_LINKS fields of insns in a chain. */
7657 clear_log_links (insns)
7661 for (i = insns; i; i = NEXT_INSN (i))
7662 if (GET_RTX_CLASS (GET_CODE (i)) == 'i')
7666 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
7667 correspond to the hard registers, if any, set in that map. This
7668 could be done far more efficiently by having all sorts of special-cases
7669 with moving single words, but probably isn't worth the trouble. */
7672 reg_set_to_hard_reg_set (to, from)
7678 EXECUTE_IF_SET_IN_BITMAP
7681 if (i >= FIRST_PSEUDO_REGISTER)
7683 SET_HARD_REG_BIT (*to, i);