Daily bump.
[official-gcc.git] / gcc / resource.c
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1 /* Definitions for computing resource usage of specific insns.
2 Copyright (C) 1999-2014 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 #include "config.h"
21 #include "system.h"
22 #include "coretypes.h"
23 #include "tm.h"
24 #include "diagnostic-core.h"
25 #include "rtl.h"
26 #include "tm_p.h"
27 #include "hard-reg-set.h"
28 #include "hashtab.h"
29 #include "hash-set.h"
30 #include "vec.h"
31 #include "machmode.h"
32 #include "input.h"
33 #include "function.h"
34 #include "regs.h"
35 #include "flags.h"
36 #include "output.h"
37 #include "dominance.h"
38 #include "cfg.h"
39 #include "predict.h"
40 #include "basic-block.h"
41 #include "resource.h"
42 #include "except.h"
43 #include "insn-attr.h"
44 #include "params.h"
45 #include "df.h"
47 /* This structure is used to record liveness information at the targets or
48 fallthrough insns of branches. We will most likely need the information
49 at targets again, so save them in a hash table rather than recomputing them
50 each time. */
52 struct target_info
54 int uid; /* INSN_UID of target. */
55 struct target_info *next; /* Next info for same hash bucket. */
56 HARD_REG_SET live_regs; /* Registers live at target. */
57 int block; /* Basic block number containing target. */
58 int bb_tick; /* Generation count of basic block info. */
61 #define TARGET_HASH_PRIME 257
63 /* Indicates what resources are required at the beginning of the epilogue. */
64 static struct resources start_of_epilogue_needs;
66 /* Indicates what resources are required at function end. */
67 static struct resources end_of_function_needs;
69 /* Define the hash table itself. */
70 static struct target_info **target_hash_table = NULL;
72 /* For each basic block, we maintain a generation number of its basic
73 block info, which is updated each time we move an insn from the
74 target of a jump. This is the generation number indexed by block
75 number. */
77 static int *bb_ticks;
79 /* Marks registers possibly live at the current place being scanned by
80 mark_target_live_regs. Also used by update_live_status. */
82 static HARD_REG_SET current_live_regs;
84 /* Marks registers for which we have seen a REG_DEAD note but no assignment.
85 Also only used by the next two functions. */
87 static HARD_REG_SET pending_dead_regs;
89 static void update_live_status (rtx, const_rtx, void *);
90 static int find_basic_block (rtx_insn *, int);
91 static rtx_insn *next_insn_no_annul (rtx_insn *);
92 static rtx_insn *find_dead_or_set_registers (rtx_insn *, struct resources*,
93 rtx *, int, struct resources,
94 struct resources);
96 /* Utility function called from mark_target_live_regs via note_stores.
97 It deadens any CLOBBERed registers and livens any SET registers. */
99 static void
100 update_live_status (rtx dest, const_rtx x, void *data ATTRIBUTE_UNUSED)
102 int first_regno, last_regno;
103 int i;
105 if (!REG_P (dest)
106 && (GET_CODE (dest) != SUBREG || !REG_P (SUBREG_REG (dest))))
107 return;
109 if (GET_CODE (dest) == SUBREG)
111 first_regno = subreg_regno (dest);
112 last_regno = first_regno + subreg_nregs (dest);
115 else
117 first_regno = REGNO (dest);
118 last_regno = END_HARD_REGNO (dest);
121 if (GET_CODE (x) == CLOBBER)
122 for (i = first_regno; i < last_regno; i++)
123 CLEAR_HARD_REG_BIT (current_live_regs, i);
124 else
125 for (i = first_regno; i < last_regno; i++)
127 SET_HARD_REG_BIT (current_live_regs, i);
128 CLEAR_HARD_REG_BIT (pending_dead_regs, i);
132 /* Find the number of the basic block with correct live register
133 information that starts closest to INSN. Return -1 if we couldn't
134 find such a basic block or the beginning is more than
135 SEARCH_LIMIT instructions before INSN. Use SEARCH_LIMIT = -1 for
136 an unlimited search.
138 The delay slot filling code destroys the control-flow graph so,
139 instead of finding the basic block containing INSN, we search
140 backwards toward a BARRIER where the live register information is
141 correct. */
143 static int
144 find_basic_block (rtx_insn *insn, int search_limit)
146 /* Scan backwards to the previous BARRIER. Then see if we can find a
147 label that starts a basic block. Return the basic block number. */
148 for (insn = prev_nonnote_insn (insn);
149 insn && !BARRIER_P (insn) && search_limit != 0;
150 insn = prev_nonnote_insn (insn), --search_limit)
153 /* The closest BARRIER is too far away. */
154 if (search_limit == 0)
155 return -1;
157 /* The start of the function. */
158 else if (insn == 0)
159 return ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb->index;
161 /* See if any of the upcoming CODE_LABELs start a basic block. If we reach
162 anything other than a CODE_LABEL or note, we can't find this code. */
163 for (insn = next_nonnote_insn (insn);
164 insn && LABEL_P (insn);
165 insn = next_nonnote_insn (insn))
166 if (BLOCK_FOR_INSN (insn))
167 return BLOCK_FOR_INSN (insn)->index;
169 return -1;
172 /* Similar to next_insn, but ignores insns in the delay slots of
173 an annulled branch. */
175 static rtx_insn *
176 next_insn_no_annul (rtx_insn *insn)
178 if (insn)
180 /* If INSN is an annulled branch, skip any insns from the target
181 of the branch. */
182 if (JUMP_P (insn)
183 && INSN_ANNULLED_BRANCH_P (insn)
184 && NEXT_INSN (PREV_INSN (insn)) != insn)
186 rtx_insn *next = NEXT_INSN (insn);
188 while ((NONJUMP_INSN_P (next) || JUMP_P (next) || CALL_P (next))
189 && INSN_FROM_TARGET_P (next))
191 insn = next;
192 next = NEXT_INSN (insn);
196 insn = NEXT_INSN (insn);
197 if (insn && NONJUMP_INSN_P (insn)
198 && GET_CODE (PATTERN (insn)) == SEQUENCE)
199 insn = as_a <rtx_sequence *> (PATTERN (insn))->insn (0);
202 return insn;
205 /* Given X, some rtl, and RES, a pointer to a `struct resource', mark
206 which resources are referenced by the insn. If INCLUDE_DELAYED_EFFECTS
207 is TRUE, resources used by the called routine will be included for
208 CALL_INSNs. */
210 void
211 mark_referenced_resources (rtx x, struct resources *res,
212 bool include_delayed_effects)
214 enum rtx_code code = GET_CODE (x);
215 int i, j;
216 unsigned int r;
217 const char *format_ptr;
219 /* Handle leaf items for which we set resource flags. Also, special-case
220 CALL, SET and CLOBBER operators. */
221 switch (code)
223 case CONST:
224 CASE_CONST_ANY:
225 case PC:
226 case SYMBOL_REF:
227 case LABEL_REF:
228 return;
230 case SUBREG:
231 if (!REG_P (SUBREG_REG (x)))
232 mark_referenced_resources (SUBREG_REG (x), res, false);
233 else
235 unsigned int regno = subreg_regno (x);
236 unsigned int last_regno = regno + subreg_nregs (x);
238 gcc_assert (last_regno <= FIRST_PSEUDO_REGISTER);
239 for (r = regno; r < last_regno; r++)
240 SET_HARD_REG_BIT (res->regs, r);
242 return;
244 case REG:
245 gcc_assert (HARD_REGISTER_P (x));
246 add_to_hard_reg_set (&res->regs, GET_MODE (x), REGNO (x));
247 return;
249 case MEM:
250 /* If this memory shouldn't change, it really isn't referencing
251 memory. */
252 if (! MEM_READONLY_P (x))
253 res->memory = 1;
254 res->volatil |= MEM_VOLATILE_P (x);
256 /* Mark registers used to access memory. */
257 mark_referenced_resources (XEXP (x, 0), res, false);
258 return;
260 case CC0:
261 res->cc = 1;
262 return;
264 case UNSPEC_VOLATILE:
265 case TRAP_IF:
266 case ASM_INPUT:
267 /* Traditional asm's are always volatile. */
268 res->volatil = 1;
269 break;
271 case ASM_OPERANDS:
272 res->volatil |= MEM_VOLATILE_P (x);
274 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
275 We can not just fall through here since then we would be confused
276 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
277 traditional asms unlike their normal usage. */
279 for (i = 0; i < ASM_OPERANDS_INPUT_LENGTH (x); i++)
280 mark_referenced_resources (ASM_OPERANDS_INPUT (x, i), res, false);
281 return;
283 case CALL:
284 /* The first operand will be a (MEM (xxx)) but doesn't really reference
285 memory. The second operand may be referenced, though. */
286 mark_referenced_resources (XEXP (XEXP (x, 0), 0), res, false);
287 mark_referenced_resources (XEXP (x, 1), res, false);
288 return;
290 case SET:
291 /* Usually, the first operand of SET is set, not referenced. But
292 registers used to access memory are referenced. SET_DEST is
293 also referenced if it is a ZERO_EXTRACT. */
295 mark_referenced_resources (SET_SRC (x), res, false);
297 x = SET_DEST (x);
298 if (GET_CODE (x) == ZERO_EXTRACT
299 || GET_CODE (x) == STRICT_LOW_PART)
300 mark_referenced_resources (x, res, false);
301 else if (GET_CODE (x) == SUBREG)
302 x = SUBREG_REG (x);
303 if (MEM_P (x))
304 mark_referenced_resources (XEXP (x, 0), res, false);
305 return;
307 case CLOBBER:
308 return;
310 case CALL_INSN:
311 if (include_delayed_effects)
313 /* A CALL references memory, the frame pointer if it exists, the
314 stack pointer, any global registers and any registers given in
315 USE insns immediately in front of the CALL.
317 However, we may have moved some of the parameter loading insns
318 into the delay slot of this CALL. If so, the USE's for them
319 don't count and should be skipped. */
320 rtx_insn *insn = PREV_INSN (as_a <rtx_insn *> (x));
321 rtx_sequence *sequence = 0;
322 int seq_size = 0;
323 int i;
325 /* If we are part of a delay slot sequence, point at the SEQUENCE. */
326 if (NEXT_INSN (insn) != x)
328 sequence = as_a <rtx_sequence *> (PATTERN (NEXT_INSN (insn)));
329 seq_size = sequence->len ();
330 gcc_assert (GET_CODE (sequence) == SEQUENCE);
333 res->memory = 1;
334 SET_HARD_REG_BIT (res->regs, STACK_POINTER_REGNUM);
335 if (frame_pointer_needed)
337 SET_HARD_REG_BIT (res->regs, FRAME_POINTER_REGNUM);
338 #if !HARD_FRAME_POINTER_IS_FRAME_POINTER
339 SET_HARD_REG_BIT (res->regs, HARD_FRAME_POINTER_REGNUM);
340 #endif
343 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
344 if (global_regs[i])
345 SET_HARD_REG_BIT (res->regs, i);
347 /* Check for a REG_SETJMP. If it exists, then we must
348 assume that this call can need any register.
350 This is done to be more conservative about how we handle setjmp.
351 We assume that they both use and set all registers. Using all
352 registers ensures that a register will not be considered dead
353 just because it crosses a setjmp call. A register should be
354 considered dead only if the setjmp call returns nonzero. */
355 if (find_reg_note (x, REG_SETJMP, NULL))
356 SET_HARD_REG_SET (res->regs);
359 rtx link;
361 for (link = CALL_INSN_FUNCTION_USAGE (x);
362 link;
363 link = XEXP (link, 1))
364 if (GET_CODE (XEXP (link, 0)) == USE)
366 for (i = 1; i < seq_size; i++)
368 rtx slot_pat = PATTERN (sequence->element (i));
369 if (GET_CODE (slot_pat) == SET
370 && rtx_equal_p (SET_DEST (slot_pat),
371 XEXP (XEXP (link, 0), 0)))
372 break;
374 if (i >= seq_size)
375 mark_referenced_resources (XEXP (XEXP (link, 0), 0),
376 res, false);
381 /* ... fall through to other INSN processing ... */
383 case INSN:
384 case JUMP_INSN:
386 if (GET_CODE (PATTERN (x)) == COND_EXEC)
387 /* In addition to the usual references, also consider all outputs
388 as referenced, to compensate for mark_set_resources treating
389 them as killed. This is similar to ZERO_EXTRACT / STRICT_LOW_PART
390 handling, execpt that we got a partial incidence instead of a partial
391 width. */
392 mark_set_resources (x, res, 0,
393 include_delayed_effects
394 ? MARK_SRC_DEST_CALL : MARK_SRC_DEST);
396 #ifdef INSN_REFERENCES_ARE_DELAYED
397 if (! include_delayed_effects
398 && INSN_REFERENCES_ARE_DELAYED (as_a <rtx_insn *> (x)))
399 return;
400 #endif
402 /* No special processing, just speed up. */
403 mark_referenced_resources (PATTERN (x), res, include_delayed_effects);
404 return;
406 default:
407 break;
410 /* Process each sub-expression and flag what it needs. */
411 format_ptr = GET_RTX_FORMAT (code);
412 for (i = 0; i < GET_RTX_LENGTH (code); i++)
413 switch (*format_ptr++)
415 case 'e':
416 mark_referenced_resources (XEXP (x, i), res, include_delayed_effects);
417 break;
419 case 'E':
420 for (j = 0; j < XVECLEN (x, i); j++)
421 mark_referenced_resources (XVECEXP (x, i, j), res,
422 include_delayed_effects);
423 break;
427 /* A subroutine of mark_target_live_regs. Search forward from TARGET
428 looking for registers that are set before they are used. These are dead.
429 Stop after passing a few conditional jumps, and/or a small
430 number of unconditional branches. */
432 static rtx_insn *
433 find_dead_or_set_registers (rtx_insn *target, struct resources *res,
434 rtx *jump_target, int jump_count,
435 struct resources set, struct resources needed)
437 HARD_REG_SET scratch;
438 rtx_insn *insn;
439 rtx_insn *next_insn;
440 rtx_insn *jump_insn = 0;
441 int i;
443 for (insn = target; insn; insn = next_insn)
445 rtx_insn *this_jump_insn = insn;
447 next_insn = NEXT_INSN (insn);
449 /* If this instruction can throw an exception, then we don't
450 know where we might end up next. That means that we have to
451 assume that whatever we have already marked as live really is
452 live. */
453 if (can_throw_internal (insn))
454 break;
456 switch (GET_CODE (insn))
458 case CODE_LABEL:
459 /* After a label, any pending dead registers that weren't yet
460 used can be made dead. */
461 AND_COMPL_HARD_REG_SET (pending_dead_regs, needed.regs);
462 AND_COMPL_HARD_REG_SET (res->regs, pending_dead_regs);
463 CLEAR_HARD_REG_SET (pending_dead_regs);
465 continue;
467 case BARRIER:
468 case NOTE:
469 continue;
471 case INSN:
472 if (GET_CODE (PATTERN (insn)) == USE)
474 /* If INSN is a USE made by update_block, we care about the
475 underlying insn. Any registers set by the underlying insn
476 are live since the insn is being done somewhere else. */
477 if (INSN_P (XEXP (PATTERN (insn), 0)))
478 mark_set_resources (XEXP (PATTERN (insn), 0), res, 0,
479 MARK_SRC_DEST_CALL);
481 /* All other USE insns are to be ignored. */
482 continue;
484 else if (GET_CODE (PATTERN (insn)) == CLOBBER)
485 continue;
486 else if (rtx_sequence *seq =
487 dyn_cast <rtx_sequence *> (PATTERN (insn)))
489 /* An unconditional jump can be used to fill the delay slot
490 of a call, so search for a JUMP_INSN in any position. */
491 for (i = 0; i < seq->len (); i++)
493 this_jump_insn = seq->insn (i);
494 if (JUMP_P (this_jump_insn))
495 break;
499 default:
500 break;
503 if (JUMP_P (this_jump_insn))
505 if (jump_count++ < 10)
507 if (any_uncondjump_p (this_jump_insn)
508 || ANY_RETURN_P (PATTERN (this_jump_insn)))
510 rtx lab_or_return = JUMP_LABEL (this_jump_insn);
511 if (ANY_RETURN_P (lab_or_return))
512 next_insn = NULL;
513 else
514 next_insn = as_a <rtx_insn *> (lab_or_return);
515 if (jump_insn == 0)
517 jump_insn = insn;
518 if (jump_target)
519 *jump_target = JUMP_LABEL (this_jump_insn);
522 else if (any_condjump_p (this_jump_insn))
524 struct resources target_set, target_res;
525 struct resources fallthrough_res;
527 /* We can handle conditional branches here by following
528 both paths, and then IOR the results of the two paths
529 together, which will give us registers that are dead
530 on both paths. Since this is expensive, we give it
531 a much higher cost than unconditional branches. The
532 cost was chosen so that we will follow at most 1
533 conditional branch. */
535 jump_count += 4;
536 if (jump_count >= 10)
537 break;
539 mark_referenced_resources (insn, &needed, true);
541 /* For an annulled branch, mark_set_resources ignores slots
542 filled by instructions from the target. This is correct
543 if the branch is not taken. Since we are following both
544 paths from the branch, we must also compute correct info
545 if the branch is taken. We do this by inverting all of
546 the INSN_FROM_TARGET_P bits, calling mark_set_resources,
547 and then inverting the INSN_FROM_TARGET_P bits again. */
549 if (GET_CODE (PATTERN (insn)) == SEQUENCE
550 && INSN_ANNULLED_BRANCH_P (this_jump_insn))
552 rtx_sequence *seq = as_a <rtx_sequence *> (PATTERN (insn));
553 for (i = 1; i < seq->len (); i++)
554 INSN_FROM_TARGET_P (seq->element (i))
555 = ! INSN_FROM_TARGET_P (seq->element (i));
557 target_set = set;
558 mark_set_resources (insn, &target_set, 0,
559 MARK_SRC_DEST_CALL);
561 for (i = 1; i < seq->len (); i++)
562 INSN_FROM_TARGET_P (seq->element (i))
563 = ! INSN_FROM_TARGET_P (seq->element (i));
565 mark_set_resources (insn, &set, 0, MARK_SRC_DEST_CALL);
567 else
569 mark_set_resources (insn, &set, 0, MARK_SRC_DEST_CALL);
570 target_set = set;
573 target_res = *res;
574 COPY_HARD_REG_SET (scratch, target_set.regs);
575 AND_COMPL_HARD_REG_SET (scratch, needed.regs);
576 AND_COMPL_HARD_REG_SET (target_res.regs, scratch);
578 fallthrough_res = *res;
579 COPY_HARD_REG_SET (scratch, set.regs);
580 AND_COMPL_HARD_REG_SET (scratch, needed.regs);
581 AND_COMPL_HARD_REG_SET (fallthrough_res.regs, scratch);
583 if (!ANY_RETURN_P (JUMP_LABEL (this_jump_insn)))
584 find_dead_or_set_registers (JUMP_LABEL_AS_INSN (this_jump_insn),
585 &target_res, 0, jump_count,
586 target_set, needed);
587 find_dead_or_set_registers (next_insn,
588 &fallthrough_res, 0, jump_count,
589 set, needed);
590 IOR_HARD_REG_SET (fallthrough_res.regs, target_res.regs);
591 AND_HARD_REG_SET (res->regs, fallthrough_res.regs);
592 break;
594 else
595 break;
597 else
599 /* Don't try this optimization if we expired our jump count
600 above, since that would mean there may be an infinite loop
601 in the function being compiled. */
602 jump_insn = 0;
603 break;
607 mark_referenced_resources (insn, &needed, true);
608 mark_set_resources (insn, &set, 0, MARK_SRC_DEST_CALL);
610 COPY_HARD_REG_SET (scratch, set.regs);
611 AND_COMPL_HARD_REG_SET (scratch, needed.regs);
612 AND_COMPL_HARD_REG_SET (res->regs, scratch);
615 return jump_insn;
618 /* Given X, a part of an insn, and a pointer to a `struct resource',
619 RES, indicate which resources are modified by the insn. If
620 MARK_TYPE is MARK_SRC_DEST_CALL, also mark resources potentially
621 set by the called routine.
623 If IN_DEST is nonzero, it means we are inside a SET. Otherwise,
624 objects are being referenced instead of set.
626 We never mark the insn as modifying the condition code unless it explicitly
627 SETs CC0 even though this is not totally correct. The reason for this is
628 that we require a SET of CC0 to immediately precede the reference to CC0.
629 So if some other insn sets CC0 as a side-effect, we know it cannot affect
630 our computation and thus may be placed in a delay slot. */
632 void
633 mark_set_resources (rtx x, struct resources *res, int in_dest,
634 enum mark_resource_type mark_type)
636 enum rtx_code code;
637 int i, j;
638 unsigned int r;
639 const char *format_ptr;
641 restart:
643 code = GET_CODE (x);
645 switch (code)
647 case NOTE:
648 case BARRIER:
649 case CODE_LABEL:
650 case USE:
651 CASE_CONST_ANY:
652 case LABEL_REF:
653 case SYMBOL_REF:
654 case CONST:
655 case PC:
656 /* These don't set any resources. */
657 return;
659 case CC0:
660 if (in_dest)
661 res->cc = 1;
662 return;
664 case CALL_INSN:
665 /* Called routine modifies the condition code, memory, any registers
666 that aren't saved across calls, global registers and anything
667 explicitly CLOBBERed immediately after the CALL_INSN. */
669 if (mark_type == MARK_SRC_DEST_CALL)
671 rtx_call_insn *call_insn = as_a <rtx_call_insn *> (x);
672 rtx link;
673 HARD_REG_SET regs;
675 res->cc = res->memory = 1;
677 get_call_reg_set_usage (call_insn, &regs, regs_invalidated_by_call);
678 IOR_HARD_REG_SET (res->regs, regs);
680 for (link = CALL_INSN_FUNCTION_USAGE (call_insn);
681 link; link = XEXP (link, 1))
682 if (GET_CODE (XEXP (link, 0)) == CLOBBER)
683 mark_set_resources (SET_DEST (XEXP (link, 0)), res, 1,
684 MARK_SRC_DEST);
686 /* Check for a REG_SETJMP. If it exists, then we must
687 assume that this call can clobber any register. */
688 if (find_reg_note (call_insn, REG_SETJMP, NULL))
689 SET_HARD_REG_SET (res->regs);
692 /* ... and also what its RTL says it modifies, if anything. */
694 case JUMP_INSN:
695 case INSN:
697 /* An insn consisting of just a CLOBBER (or USE) is just for flow
698 and doesn't actually do anything, so we ignore it. */
700 #ifdef INSN_SETS_ARE_DELAYED
701 if (mark_type != MARK_SRC_DEST_CALL
702 && INSN_SETS_ARE_DELAYED (as_a <rtx_insn *> (x)))
703 return;
704 #endif
706 x = PATTERN (x);
707 if (GET_CODE (x) != USE && GET_CODE (x) != CLOBBER)
708 goto restart;
709 return;
711 case SET:
712 /* If the source of a SET is a CALL, this is actually done by
713 the called routine. So only include it if we are to include the
714 effects of the calling routine. */
716 mark_set_resources (SET_DEST (x), res,
717 (mark_type == MARK_SRC_DEST_CALL
718 || GET_CODE (SET_SRC (x)) != CALL),
719 mark_type);
721 mark_set_resources (SET_SRC (x), res, 0, MARK_SRC_DEST);
722 return;
724 case CLOBBER:
725 mark_set_resources (XEXP (x, 0), res, 1, MARK_SRC_DEST);
726 return;
728 case SEQUENCE:
730 rtx_sequence *seq = as_a <rtx_sequence *> (x);
731 rtx control = seq->element (0);
732 bool annul_p = JUMP_P (control) && INSN_ANNULLED_BRANCH_P (control);
734 mark_set_resources (control, res, 0, mark_type);
735 for (i = seq->len () - 1; i >= 0; --i)
737 rtx elt = seq->element (i);
738 if (!annul_p && INSN_FROM_TARGET_P (elt))
739 mark_set_resources (elt, res, 0, mark_type);
742 return;
744 case POST_INC:
745 case PRE_INC:
746 case POST_DEC:
747 case PRE_DEC:
748 mark_set_resources (XEXP (x, 0), res, 1, MARK_SRC_DEST);
749 return;
751 case PRE_MODIFY:
752 case POST_MODIFY:
753 mark_set_resources (XEXP (x, 0), res, 1, MARK_SRC_DEST);
754 mark_set_resources (XEXP (XEXP (x, 1), 0), res, 0, MARK_SRC_DEST);
755 mark_set_resources (XEXP (XEXP (x, 1), 1), res, 0, MARK_SRC_DEST);
756 return;
758 case SIGN_EXTRACT:
759 case ZERO_EXTRACT:
760 mark_set_resources (XEXP (x, 0), res, in_dest, MARK_SRC_DEST);
761 mark_set_resources (XEXP (x, 1), res, 0, MARK_SRC_DEST);
762 mark_set_resources (XEXP (x, 2), res, 0, MARK_SRC_DEST);
763 return;
765 case MEM:
766 if (in_dest)
768 res->memory = 1;
769 res->volatil |= MEM_VOLATILE_P (x);
772 mark_set_resources (XEXP (x, 0), res, 0, MARK_SRC_DEST);
773 return;
775 case SUBREG:
776 if (in_dest)
778 if (!REG_P (SUBREG_REG (x)))
779 mark_set_resources (SUBREG_REG (x), res, in_dest, mark_type);
780 else
782 unsigned int regno = subreg_regno (x);
783 unsigned int last_regno = regno + subreg_nregs (x);
785 gcc_assert (last_regno <= FIRST_PSEUDO_REGISTER);
786 for (r = regno; r < last_regno; r++)
787 SET_HARD_REG_BIT (res->regs, r);
790 return;
792 case REG:
793 if (in_dest)
795 gcc_assert (HARD_REGISTER_P (x));
796 add_to_hard_reg_set (&res->regs, GET_MODE (x), REGNO (x));
798 return;
800 case UNSPEC_VOLATILE:
801 case ASM_INPUT:
802 /* Traditional asm's are always volatile. */
803 res->volatil = 1;
804 return;
806 case TRAP_IF:
807 res->volatil = 1;
808 break;
810 case ASM_OPERANDS:
811 res->volatil |= MEM_VOLATILE_P (x);
813 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
814 We can not just fall through here since then we would be confused
815 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
816 traditional asms unlike their normal usage. */
818 for (i = 0; i < ASM_OPERANDS_INPUT_LENGTH (x); i++)
819 mark_set_resources (ASM_OPERANDS_INPUT (x, i), res, in_dest,
820 MARK_SRC_DEST);
821 return;
823 default:
824 break;
827 /* Process each sub-expression and flag what it needs. */
828 format_ptr = GET_RTX_FORMAT (code);
829 for (i = 0; i < GET_RTX_LENGTH (code); i++)
830 switch (*format_ptr++)
832 case 'e':
833 mark_set_resources (XEXP (x, i), res, in_dest, mark_type);
834 break;
836 case 'E':
837 for (j = 0; j < XVECLEN (x, i); j++)
838 mark_set_resources (XVECEXP (x, i, j), res, in_dest, mark_type);
839 break;
843 /* Return TRUE if INSN is a return, possibly with a filled delay slot. */
845 static bool
846 return_insn_p (const_rtx insn)
848 if (JUMP_P (insn) && ANY_RETURN_P (PATTERN (insn)))
849 return true;
851 if (NONJUMP_INSN_P (insn) && GET_CODE (PATTERN (insn)) == SEQUENCE)
852 return return_insn_p (XVECEXP (PATTERN (insn), 0, 0));
854 return false;
857 /* Set the resources that are live at TARGET.
859 If TARGET is zero, we refer to the end of the current function and can
860 return our precomputed value.
862 Otherwise, we try to find out what is live by consulting the basic block
863 information. This is tricky, because we must consider the actions of
864 reload and jump optimization, which occur after the basic block information
865 has been computed.
867 Accordingly, we proceed as follows::
869 We find the previous BARRIER and look at all immediately following labels
870 (with no intervening active insns) to see if any of them start a basic
871 block. If we hit the start of the function first, we use block 0.
873 Once we have found a basic block and a corresponding first insn, we can
874 accurately compute the live status (by starting at a label following a
875 BARRIER, we are immune to actions taken by reload and jump.) Then we
876 scan all insns between that point and our target. For each CLOBBER (or
877 for call-clobbered regs when we pass a CALL_INSN), mark the appropriate
878 registers are dead. For a SET, mark them as live.
880 We have to be careful when using REG_DEAD notes because they are not
881 updated by such things as find_equiv_reg. So keep track of registers
882 marked as dead that haven't been assigned to, and mark them dead at the
883 next CODE_LABEL since reload and jump won't propagate values across labels.
885 If we cannot find the start of a basic block (should be a very rare
886 case, if it can happen at all), mark everything as potentially live.
888 Next, scan forward from TARGET looking for things set or clobbered
889 before they are used. These are not live.
891 Because we can be called many times on the same target, save our results
892 in a hash table indexed by INSN_UID. This is only done if the function
893 init_resource_info () was invoked before we are called. */
895 void
896 mark_target_live_regs (rtx_insn *insns, rtx target_maybe_return, struct resources *res)
898 int b = -1;
899 unsigned int i;
900 struct target_info *tinfo = NULL;
901 rtx_insn *insn;
902 rtx jump_insn = 0;
903 rtx jump_target;
904 HARD_REG_SET scratch;
905 struct resources set, needed;
907 /* Handle end of function. */
908 if (target_maybe_return == 0 || ANY_RETURN_P (target_maybe_return))
910 *res = end_of_function_needs;
911 return;
914 /* We've handled the case of RETURN/SIMPLE_RETURN; we should now have an
915 instruction. */
916 rtx_insn *target = as_a <rtx_insn *> (target_maybe_return);
918 /* Handle return insn. */
919 if (return_insn_p (target))
921 *res = end_of_function_needs;
922 mark_referenced_resources (target, res, false);
923 return;
926 /* We have to assume memory is needed, but the CC isn't. */
927 res->memory = 1;
928 res->volatil = 0;
929 res->cc = 0;
931 /* See if we have computed this value already. */
932 if (target_hash_table != NULL)
934 for (tinfo = target_hash_table[INSN_UID (target) % TARGET_HASH_PRIME];
935 tinfo; tinfo = tinfo->next)
936 if (tinfo->uid == INSN_UID (target))
937 break;
939 /* Start by getting the basic block number. If we have saved
940 information, we can get it from there unless the insn at the
941 start of the basic block has been deleted. */
942 if (tinfo && tinfo->block != -1
943 && ! BB_HEAD (BASIC_BLOCK_FOR_FN (cfun, tinfo->block))->deleted ())
944 b = tinfo->block;
947 if (b == -1)
948 b = find_basic_block (target, MAX_DELAY_SLOT_LIVE_SEARCH);
950 if (target_hash_table != NULL)
952 if (tinfo)
954 /* If the information is up-to-date, use it. Otherwise, we will
955 update it below. */
956 if (b == tinfo->block && b != -1 && tinfo->bb_tick == bb_ticks[b])
958 COPY_HARD_REG_SET (res->regs, tinfo->live_regs);
959 return;
962 else
964 /* Allocate a place to put our results and chain it into the
965 hash table. */
966 tinfo = XNEW (struct target_info);
967 tinfo->uid = INSN_UID (target);
968 tinfo->block = b;
969 tinfo->next
970 = target_hash_table[INSN_UID (target) % TARGET_HASH_PRIME];
971 target_hash_table[INSN_UID (target) % TARGET_HASH_PRIME] = tinfo;
975 CLEAR_HARD_REG_SET (pending_dead_regs);
977 /* If we found a basic block, get the live registers from it and update
978 them with anything set or killed between its start and the insn before
979 TARGET; this custom life analysis is really about registers so we need
980 to use the LR problem. Otherwise, we must assume everything is live. */
981 if (b != -1)
983 regset regs_live = DF_LR_IN (BASIC_BLOCK_FOR_FN (cfun, b));
984 rtx_insn *start_insn, *stop_insn;
986 /* Compute hard regs live at start of block. */
987 REG_SET_TO_HARD_REG_SET (current_live_regs, regs_live);
989 /* Get starting and ending insn, handling the case where each might
990 be a SEQUENCE. */
991 start_insn = (b == ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb->index ?
992 insns : BB_HEAD (BASIC_BLOCK_FOR_FN (cfun, b)));
993 stop_insn = target;
995 if (NONJUMP_INSN_P (start_insn)
996 && GET_CODE (PATTERN (start_insn)) == SEQUENCE)
997 start_insn = as_a <rtx_sequence *> (PATTERN (start_insn))->insn (0);
999 if (NONJUMP_INSN_P (stop_insn)
1000 && GET_CODE (PATTERN (stop_insn)) == SEQUENCE)
1001 stop_insn = next_insn (PREV_INSN (stop_insn));
1003 for (insn = start_insn; insn != stop_insn;
1004 insn = next_insn_no_annul (insn))
1006 rtx link;
1007 rtx_insn *real_insn = insn;
1008 enum rtx_code code = GET_CODE (insn);
1010 if (DEBUG_INSN_P (insn))
1011 continue;
1013 /* If this insn is from the target of a branch, it isn't going to
1014 be used in the sequel. If it is used in both cases, this
1015 test will not be true. */
1016 if ((code == INSN || code == JUMP_INSN || code == CALL_INSN)
1017 && INSN_FROM_TARGET_P (insn))
1018 continue;
1020 /* If this insn is a USE made by update_block, we care about the
1021 underlying insn. */
1022 if (code == INSN
1023 && GET_CODE (PATTERN (insn)) == USE
1024 && INSN_P (XEXP (PATTERN (insn), 0)))
1025 real_insn = as_a <rtx_insn *> (XEXP (PATTERN (insn), 0));
1027 if (CALL_P (real_insn))
1029 /* Values in call-clobbered registers survive a COND_EXEC CALL
1030 if that is not executed; this matters for resoure use because
1031 they may be used by a complementarily (or more strictly)
1032 predicated instruction, or if the CALL is NORETURN. */
1033 if (GET_CODE (PATTERN (real_insn)) != COND_EXEC)
1035 HARD_REG_SET regs_invalidated_by_this_call;
1036 get_call_reg_set_usage (real_insn,
1037 &regs_invalidated_by_this_call,
1038 regs_invalidated_by_call);
1039 /* CALL clobbers all call-used regs that aren't fixed except
1040 sp, ap, and fp. Do this before setting the result of the
1041 call live. */
1042 AND_COMPL_HARD_REG_SET (current_live_regs,
1043 regs_invalidated_by_this_call);
1046 /* A CALL_INSN sets any global register live, since it may
1047 have been modified by the call. */
1048 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1049 if (global_regs[i])
1050 SET_HARD_REG_BIT (current_live_regs, i);
1053 /* Mark anything killed in an insn to be deadened at the next
1054 label. Ignore USE insns; the only REG_DEAD notes will be for
1055 parameters. But they might be early. A CALL_INSN will usually
1056 clobber registers used for parameters. It isn't worth bothering
1057 with the unlikely case when it won't. */
1058 if ((NONJUMP_INSN_P (real_insn)
1059 && GET_CODE (PATTERN (real_insn)) != USE
1060 && GET_CODE (PATTERN (real_insn)) != CLOBBER)
1061 || JUMP_P (real_insn)
1062 || CALL_P (real_insn))
1064 for (link = REG_NOTES (real_insn); link; link = XEXP (link, 1))
1065 if (REG_NOTE_KIND (link) == REG_DEAD
1066 && REG_P (XEXP (link, 0))
1067 && REGNO (XEXP (link, 0)) < FIRST_PSEUDO_REGISTER)
1068 add_to_hard_reg_set (&pending_dead_regs,
1069 GET_MODE (XEXP (link, 0)),
1070 REGNO (XEXP (link, 0)));
1072 note_stores (PATTERN (real_insn), update_live_status, NULL);
1074 /* If any registers were unused after this insn, kill them.
1075 These notes will always be accurate. */
1076 for (link = REG_NOTES (real_insn); link; link = XEXP (link, 1))
1077 if (REG_NOTE_KIND (link) == REG_UNUSED
1078 && REG_P (XEXP (link, 0))
1079 && REGNO (XEXP (link, 0)) < FIRST_PSEUDO_REGISTER)
1080 remove_from_hard_reg_set (&current_live_regs,
1081 GET_MODE (XEXP (link, 0)),
1082 REGNO (XEXP (link, 0)));
1085 else if (LABEL_P (real_insn))
1087 basic_block bb;
1089 /* A label clobbers the pending dead registers since neither
1090 reload nor jump will propagate a value across a label. */
1091 AND_COMPL_HARD_REG_SET (current_live_regs, pending_dead_regs);
1092 CLEAR_HARD_REG_SET (pending_dead_regs);
1094 /* We must conservatively assume that all registers that used
1095 to be live here still are. The fallthrough edge may have
1096 left a live register uninitialized. */
1097 bb = BLOCK_FOR_INSN (real_insn);
1098 if (bb)
1100 HARD_REG_SET extra_live;
1102 REG_SET_TO_HARD_REG_SET (extra_live, DF_LR_IN (bb));
1103 IOR_HARD_REG_SET (current_live_regs, extra_live);
1107 /* The beginning of the epilogue corresponds to the end of the
1108 RTL chain when there are no epilogue insns. Certain resources
1109 are implicitly required at that point. */
1110 else if (NOTE_P (real_insn)
1111 && NOTE_KIND (real_insn) == NOTE_INSN_EPILOGUE_BEG)
1112 IOR_HARD_REG_SET (current_live_regs, start_of_epilogue_needs.regs);
1115 COPY_HARD_REG_SET (res->regs, current_live_regs);
1116 if (tinfo != NULL)
1118 tinfo->block = b;
1119 tinfo->bb_tick = bb_ticks[b];
1122 else
1123 /* We didn't find the start of a basic block. Assume everything
1124 in use. This should happen only extremely rarely. */
1125 SET_HARD_REG_SET (res->regs);
1127 CLEAR_RESOURCE (&set);
1128 CLEAR_RESOURCE (&needed);
1130 jump_insn = find_dead_or_set_registers (target, res, &jump_target, 0,
1131 set, needed);
1133 /* If we hit an unconditional branch, we have another way of finding out
1134 what is live: we can see what is live at the branch target and include
1135 anything used but not set before the branch. We add the live
1136 resources found using the test below to those found until now. */
1138 if (jump_insn)
1140 struct resources new_resources;
1141 rtx_insn *stop_insn = next_active_insn (jump_insn);
1143 if (!ANY_RETURN_P (jump_target))
1144 jump_target = next_active_insn (jump_target);
1145 mark_target_live_regs (insns, jump_target, &new_resources);
1146 CLEAR_RESOURCE (&set);
1147 CLEAR_RESOURCE (&needed);
1149 /* Include JUMP_INSN in the needed registers. */
1150 for (insn = target; insn != stop_insn; insn = next_active_insn (insn))
1152 mark_referenced_resources (insn, &needed, true);
1154 COPY_HARD_REG_SET (scratch, needed.regs);
1155 AND_COMPL_HARD_REG_SET (scratch, set.regs);
1156 IOR_HARD_REG_SET (new_resources.regs, scratch);
1158 mark_set_resources (insn, &set, 0, MARK_SRC_DEST_CALL);
1161 IOR_HARD_REG_SET (res->regs, new_resources.regs);
1164 if (tinfo != NULL)
1166 COPY_HARD_REG_SET (tinfo->live_regs, res->regs);
1170 /* Initialize the resources required by mark_target_live_regs ().
1171 This should be invoked before the first call to mark_target_live_regs. */
1173 void
1174 init_resource_info (rtx_insn *epilogue_insn)
1176 int i;
1177 basic_block bb;
1179 /* Indicate what resources are required to be valid at the end of the current
1180 function. The condition code never is and memory always is.
1181 The stack pointer is needed unless EXIT_IGNORE_STACK is true
1182 and there is an epilogue that restores the original stack pointer
1183 from the frame pointer. Registers used to return the function value
1184 are needed. Registers holding global variables are needed. */
1186 end_of_function_needs.cc = 0;
1187 end_of_function_needs.memory = 1;
1188 CLEAR_HARD_REG_SET (end_of_function_needs.regs);
1190 if (frame_pointer_needed)
1192 SET_HARD_REG_BIT (end_of_function_needs.regs, FRAME_POINTER_REGNUM);
1193 #if !HARD_FRAME_POINTER_IS_FRAME_POINTER
1194 SET_HARD_REG_BIT (end_of_function_needs.regs, HARD_FRAME_POINTER_REGNUM);
1195 #endif
1197 if (!(frame_pointer_needed
1198 && EXIT_IGNORE_STACK
1199 && epilogue_insn
1200 && !crtl->sp_is_unchanging))
1201 SET_HARD_REG_BIT (end_of_function_needs.regs, STACK_POINTER_REGNUM);
1203 if (crtl->return_rtx != 0)
1204 mark_referenced_resources (crtl->return_rtx,
1205 &end_of_function_needs, true);
1207 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1208 if (global_regs[i]
1209 #ifdef EPILOGUE_USES
1210 || EPILOGUE_USES (i)
1211 #endif
1213 SET_HARD_REG_BIT (end_of_function_needs.regs, i);
1215 /* The registers required to be live at the end of the function are
1216 represented in the flow information as being dead just prior to
1217 reaching the end of the function. For example, the return of a value
1218 might be represented by a USE of the return register immediately
1219 followed by an unconditional jump to the return label where the
1220 return label is the end of the RTL chain. The end of the RTL chain
1221 is then taken to mean that the return register is live.
1223 This sequence is no longer maintained when epilogue instructions are
1224 added to the RTL chain. To reconstruct the original meaning, the
1225 start of the epilogue (NOTE_INSN_EPILOGUE_BEG) is regarded as the
1226 point where these registers become live (start_of_epilogue_needs).
1227 If epilogue instructions are present, the registers set by those
1228 instructions won't have been processed by flow. Thus, those
1229 registers are additionally required at the end of the RTL chain
1230 (end_of_function_needs). */
1232 start_of_epilogue_needs = end_of_function_needs;
1234 while ((epilogue_insn = next_nonnote_insn (epilogue_insn)))
1236 mark_set_resources (epilogue_insn, &end_of_function_needs, 0,
1237 MARK_SRC_DEST_CALL);
1238 if (return_insn_p (epilogue_insn))
1239 break;
1242 /* Allocate and initialize the tables used by mark_target_live_regs. */
1243 target_hash_table = XCNEWVEC (struct target_info *, TARGET_HASH_PRIME);
1244 bb_ticks = XCNEWVEC (int, last_basic_block_for_fn (cfun));
1246 /* Set the BLOCK_FOR_INSN of each label that starts a basic block. */
1247 FOR_EACH_BB_FN (bb, cfun)
1248 if (LABEL_P (BB_HEAD (bb)))
1249 BLOCK_FOR_INSN (BB_HEAD (bb)) = bb;
1252 /* Free up the resources allocated to mark_target_live_regs (). This
1253 should be invoked after the last call to mark_target_live_regs (). */
1255 void
1256 free_resource_info (void)
1258 basic_block bb;
1260 if (target_hash_table != NULL)
1262 int i;
1264 for (i = 0; i < TARGET_HASH_PRIME; ++i)
1266 struct target_info *ti = target_hash_table[i];
1268 while (ti)
1270 struct target_info *next = ti->next;
1271 free (ti);
1272 ti = next;
1276 free (target_hash_table);
1277 target_hash_table = NULL;
1280 if (bb_ticks != NULL)
1282 free (bb_ticks);
1283 bb_ticks = NULL;
1286 FOR_EACH_BB_FN (bb, cfun)
1287 if (LABEL_P (BB_HEAD (bb)))
1288 BLOCK_FOR_INSN (BB_HEAD (bb)) = NULL;
1291 /* Clear any hashed information that we have stored for INSN. */
1293 void
1294 clear_hashed_info_for_insn (rtx_insn *insn)
1296 struct target_info *tinfo;
1298 if (target_hash_table != NULL)
1300 for (tinfo = target_hash_table[INSN_UID (insn) % TARGET_HASH_PRIME];
1301 tinfo; tinfo = tinfo->next)
1302 if (tinfo->uid == INSN_UID (insn))
1303 break;
1305 if (tinfo)
1306 tinfo->block = -1;
1310 /* Increment the tick count for the basic block that contains INSN. */
1312 void
1313 incr_ticks_for_insn (rtx_insn *insn)
1315 int b = find_basic_block (insn, MAX_DELAY_SLOT_LIVE_SEARCH);
1317 if (b != -1)
1318 bb_ticks[b]++;
1321 /* Add TRIAL to the set of resources used at the end of the current
1322 function. */
1323 void
1324 mark_end_of_function_resources (rtx trial, bool include_delayed_effects)
1326 mark_referenced_resources (trial, &end_of_function_needs,
1327 include_delayed_effects);