1 /* RTL factoring (sequence abstraction).
2 Copyright (C) 2004, 2005, 2006, 2007 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 2, or (at your option) any later
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
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to the Free
18 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
23 #include "coretypes.h"
27 #include "basic-block.h"
35 #include "tree-pass.h"
36 #include "tree-flow.h"
40 #include "addresses.h"
42 /* Sequence abstraction:
44 It is a size optimization method. The main idea of this technique is to
45 find identical sequences of code, which can be turned into procedures and
46 then replace all occurrences with calls to the newly created subroutine.
47 It is kind of an opposite of function inlining.
49 There are four major parts of this file:
52 In order to avoid the comparison of every insn with every other, hash
53 value will be designed for every insn by COMPUTE_HASH.
54 These hash values are used for grouping the sequence candidates. So
55 we only need to compare every insn with every other in same hash group.
57 FILL_HASH_BUCKET creates all hash values and stores into HASH_BUCKETS.
58 The result is used by COLLECT_PATTERN_SEQS.
61 In code matching the algorithm compares every two possible sequence
62 candidates which last insns are in the same hash group. If these
63 sequences are identical they will be stored and do further searches for
64 finding more sequences which are identical with the first one.
66 COLLECT_PATTERN_SEQS does the code matching and stores the results into
70 This part computes the gain of abstraction which could be archived when
71 turning the pattern sequence into a pseudo-function and its matching
72 sequences into pseudo-calls. After it the most effective sequences will
73 be marked for abstraction.
75 RECOMPUTE_GAIN does the gain computation. The sequences with the maximum
76 gain is on the top of PATTERN_SEQS.
79 This part turns the pattern sequence into a pseudo-function and its
80 matching sequences into pseudo-calls.
82 ABSTRACT_BEST_SEQ does the code merging.
87 // Original source // After sequence abstraction
91 jump_label = &&exit_0;
100 jump_label = &&exit_1;
108 jump_label = &&exit_2;
116 jump_label = &&exit_3;
128 - Use REG_ALLOC_ORDER when choosing link register.
129 - Handle JUMP_INSNs. Also handle volatile function calls (handle them
130 similar to unconditional jumps.)
131 - Test command line option -fpic.
134 /* Predicate yielding nonzero iff X is an abstractable insn. Non-jump insns are
136 #define ABSTRACTABLE_INSN_P(X) (INSN_P (X) && !JUMP_P (X))
138 /* First parameter of the htab_create function call. */
139 #define HASH_INIT 1023
141 /* Multiplier for cost of sequence call to avoid abstracting short
143 #ifndef SEQ_CALL_COST_MULTIPLIER
144 #define SEQ_CALL_COST_MULTIPLIER 2
147 /* Recomputes the cost of MSEQ pattern/matching sequence. */
148 #define RECOMPUTE_COST(SEQ) \
153 for (l = 0; l < SEQ->abstracted_length; l++) \
155 SEQ->cost += compute_rtx_cost (x); \
156 x = prev_insn_in_block (x); \
160 /* A sequence matching a pattern sequence. */
161 typedef struct matching_seq_def
163 /* The last insn in the matching sequence. */
166 /* Index of INSN instruction. */
169 /* The number of insns matching in this sequence and the pattern sequence.
173 /* The number of insns selected to abstract from this sequence. Less than
174 or equal to MATCHING_LENGTH. */
175 int abstracted_length;
177 /* The cost of the sequence. */
180 /* The next sequence in the chain matching the same pattern. */
181 struct matching_seq_def *next_matching_seq;
185 /* A pattern instruction sequence. */
186 typedef struct pattern_seq_def
188 /* The last insn in the pattern sequence. */
191 /* Index of INSN instruction. */
194 /* The gain of transforming the pattern sequence into a pseudo-function and
195 the matching sequences into pseudo-calls. */
198 /* The maximum of the ABSTRACTED_LENGTH of the matching sequences. */
199 int abstracted_length;
201 /* The cost of the sequence. */
204 /* The register used to hold the return address during the pseudo-call. */
207 /* The sequences matching this pattern. */
208 matching_seq matching_seqs;
210 /* The next pattern sequence in the chain. */
211 struct pattern_seq_def *next_pattern_seq;
215 /* A block of a pattern sequence. */
216 typedef struct seq_block_def
218 /* The number of insns in the block. */
221 /* The code_label of the block. */
224 /* The sequences entering the pattern sequence at LABEL. */
225 matching_seq matching_seqs;
227 /* The next block in the chain. The blocks are sorted by LENGTH in
229 struct seq_block_def *next_seq_block;
232 /* Contains same sequence candidates for further searching. */
233 typedef struct hash_bucket_def
235 /* The hash value of the group. */
238 /* List of sequence candidates. */
239 htab_t seq_candidates;
242 /* Contains the last insn of the sequence, and its index value. */
243 typedef struct hash_elem_def
245 /* Unique index; ordered by FILL_HASH_BUCKET. */
248 /* The last insn in the sequence. */
251 /* The cached length of the insn. */
255 /* The list of same sequence candidates. */
256 static htab_t hash_buckets;
258 /* The pattern sequences collected from the current functions. */
259 static pattern_seq pattern_seqs;
261 /* The blocks of the current pattern sequence. */
262 static seq_block seq_blocks;
264 /* Cost of calling sequence. */
265 static int seq_call_cost;
268 static int seq_jump_cost;
270 /* Cost of returning. */
271 static int seq_return_cost;
273 /* Returns the first insn preceding INSN for which INSN_P is true and belongs to
274 the same basic block. Returns NULL_RTX if no such insn can be found. */
277 prev_insn_in_block (rtx insn)
279 basic_block bb = BLOCK_FOR_INSN (insn);
284 while (insn != BB_HEAD (bb))
286 insn = PREV_INSN (insn);
293 /* Returns the hash value of INSN. */
296 compute_hash (rtx insn)
298 unsigned int hash = 0;
301 hash = INSN_CODE (insn) * 100;
303 prev = prev_insn_in_block (insn);
305 hash += INSN_CODE (prev);
310 /* Compute the cost of INSN rtx for abstraction. */
313 compute_rtx_cost (rtx insn)
315 struct hash_bucket_def tmp_bucket;
316 p_hash_bucket bucket;
317 struct hash_elem_def tmp_elem;
318 p_hash_elem elem = NULL;
321 /* Compute hash value for INSN. */
322 tmp_bucket.hash = compute_hash (insn);
324 /* Select the hash group. */
325 bucket = htab_find (hash_buckets, &tmp_bucket);
329 tmp_elem.insn = insn;
331 /* Select the insn. */
332 elem = htab_find (bucket->seq_candidates, &tmp_elem);
334 /* If INSN is parsed the cost will be the cached length. */
339 /* If we can't parse the INSN cost will be the instruction length. */
342 cost = get_attr_length (insn);
344 /* Cache the length. */
349 /* If we can't get an accurate estimate for a complex instruction,
350 assume that it has the same cost as a single fast instruction. */
351 return cost != 0 ? cost : COSTS_N_INSNS (1);
354 /* Determines the number of common insns in the sequences ending in INSN1 and
355 INSN2. Returns with LEN number of common insns and COST cost of sequence.
359 matching_length (rtx insn1, rtx insn2, int* len, int* cost)
368 while (x1 && x2 && (x1 != insn2) && (x2 != insn1)
369 && rtx_equal_p (PATTERN (x1), PATTERN (x2)))
372 (*cost) += compute_rtx_cost (x1);
373 x1 = prev_insn_in_block (x1);
374 x2 = prev_insn_in_block (x2);
378 /* Adds E0 as a pattern sequence to PATTERN_SEQS with E1 as a matching
382 match_seqs (p_hash_elem e0, p_hash_elem e1)
386 matching_seq mseq, p_prev, p_next;
388 /* Determines the cost of the sequence and return without doing anything
389 if it is too small to produce any gain. */
390 matching_length (e0->insn, e1->insn, &len, &cost);
391 if (cost <= seq_call_cost)
394 /* Prepend a new PATTERN_SEQ to PATTERN_SEQS if the last pattern sequence
395 does not end in E0->INSN. This assumes that once the E0->INSN changes
396 the old value will never appear again. */
397 if (!pattern_seqs || pattern_seqs->insn != e0->insn)
400 (pattern_seq) xmalloc (sizeof (struct pattern_seq_def));
401 pseq->insn = e0->insn;
403 pseq->gain = 0; /* Set to zero to force recomputing. */
404 pseq->abstracted_length = 0;
406 pseq->link_reg = NULL_RTX;
407 pseq->matching_seqs = NULL;
408 pseq->next_pattern_seq = pattern_seqs;
412 /* Find the position of E1 in the matching sequences list. */
414 p_next = pattern_seqs->matching_seqs;
415 while (p_next && p_next->idx < e1->idx)
418 p_next = p_next->next_matching_seq;
421 /* Add a new E1 matching sequence to the pattern sequence. We know that
422 it ends in E0->INSN. */
423 mseq = (matching_seq) xmalloc (sizeof (struct matching_seq_def));
424 mseq->insn = e1->insn;
426 mseq->matching_length = len;
427 mseq->abstracted_length = 0;
431 pattern_seqs->matching_seqs = mseq;
433 p_prev->next_matching_seq = mseq;
434 mseq->next_matching_seq = p_next;
437 /* Collects all pattern sequences and their matching sequences and puts them
438 into PATTERN_SEQS. */
441 collect_pattern_seqs (void)
443 htab_iterator hti0, hti1, hti2;
444 p_hash_bucket hash_bucket;
448 bitmap_head stack_reg_live;
450 /* Extra initialization step to ensure that no stack registers (if present)
451 are live across abnormal edges. Set a flag in STACK_REG_LIVE for an insn
452 if a stack register is live after the insn. */
453 bitmap_initialize (&stack_reg_live, NULL);
461 /* Initialize liveness propagation. */
462 INIT_REG_SET (&live);
463 bitmap_copy (&live, DF_LR_OUT (bb));
464 df_simulate_artificial_refs_at_end (bb, &live);
466 /* Propagate liveness info and mark insns where a stack reg is live. */
468 for (insn = BB_END (bb); ; insn = prev)
470 prev = PREV_INSN (insn);
474 for (reg = FIRST_STACK_REG; reg <= LAST_STACK_REG; reg++)
476 if (REGNO_REG_SET_P (&live, reg))
478 bitmap_set_bit (&stack_reg_live, INSN_UID (insn));
484 if (insn == BB_HEAD (bb))
486 df_simulate_one_insn_backwards (bb, insn, &live);
490 /* Free unused data. */
491 CLEAR_REG_SET (&live);
495 /* Initialize PATTERN_SEQS to empty. */
498 /* Try to match every abstractable insn with every other insn in the same
501 FOR_EACH_HTAB_ELEMENT (hash_buckets, hash_bucket, p_hash_bucket, hti0)
502 if (htab_elements (hash_bucket->seq_candidates) > 1)
503 FOR_EACH_HTAB_ELEMENT (hash_bucket->seq_candidates, e0, p_hash_elem, hti1)
504 FOR_EACH_HTAB_ELEMENT (hash_bucket->seq_candidates, e1, p_hash_elem,
508 && !bitmap_bit_p (&stack_reg_live, INSN_UID (e0->insn))
509 && !bitmap_bit_p (&stack_reg_live, INSN_UID (e1->insn))
514 /* Free unused data. */
515 bitmap_clear (&stack_reg_live);
519 /* Transforms a regset to a HARD_REG_SET. Every hard register in REGS is added
520 to hregs. Additionally, the hard counterpart of every renumbered pseudo
521 register is also added. */
524 renumbered_reg_set_to_hard_reg_set (HARD_REG_SET * hregs, regset regs)
528 REG_SET_TO_HARD_REG_SET (*hregs, regs);
529 for (r = FIRST_PSEUDO_REGISTER; r < max_regno; r++)
530 if (REGNO_REG_SET_P (regs, r) && reg_renumber[r] >= 0)
531 SET_HARD_REG_BIT (*hregs, reg_renumber[r]);
534 /* Clears the bits in REGS for all registers, which are live in the sequence
535 give by its last INSN and its LENGTH. */
538 clear_regs_live_in_seq (HARD_REG_SET * regs, rtx insn, int length)
546 /* Initialize liveness propagation. */
547 bb = BLOCK_FOR_INSN (insn);
548 INIT_REG_SET (&live);
549 bitmap_copy (&live, DF_LR_OUT (bb));
550 df_simulate_artificial_refs_at_end (bb, &live);
552 /* Propagate until INSN if found. */
553 for (x = BB_END (bb); x != insn;)
554 df_simulate_one_insn_backwards (bb, insn, &live);
556 /* Clear registers live after INSN. */
557 renumbered_reg_set_to_hard_reg_set (&hlive, &live);
558 AND_COMPL_HARD_REG_SET (*regs, hlive);
560 /* Clear registers live in and before the sequence. */
561 for (i = 0; i < length;)
563 rtx prev = PREV_INSN (x);
564 df_simulate_one_insn_backwards (bb, insn, &live);
568 renumbered_reg_set_to_hard_reg_set (&hlive, &live);
569 AND_COMPL_HARD_REG_SET (*regs, hlive);
576 /* Free unused data. */
577 CLEAR_REG_SET (&live);
580 /* Computes the gain of turning PSEQ into a pseudo-function and its matching
581 sequences into pseudo-calls. Also computes and caches the number of insns to
582 abstract from the matching sequences. */
585 recompute_gain_for_pattern_seq (pattern_seq pseq)
591 HARD_REG_SET linkregs;
593 /* Initialize data. */
594 SET_HARD_REG_SET (linkregs);
595 pseq->link_reg = NULL_RTX;
596 pseq->abstracted_length = 0;
598 pseq->gain = -(seq_call_cost - seq_jump_cost + seq_return_cost);
600 /* Determine ABSTRACTED_LENGTH and COST for matching sequences of PSEQ.
601 ABSTRACTED_LENGTH may be less than MATCHING_LENGTH if sequences in the
602 same block overlap. */
604 for (mseq = pseq->matching_seqs; mseq; mseq = mseq->next_matching_seq)
606 /* Determine ABSTRACTED_LENGTH. */
607 if (mseq->next_matching_seq)
608 mseq->abstracted_length = (int)(mseq->next_matching_seq->idx -
611 mseq->abstracted_length = mseq->matching_length;
613 if (mseq->abstracted_length > mseq->matching_length)
614 mseq->abstracted_length = mseq->matching_length;
616 /* Compute the cost of sequence. */
617 RECOMPUTE_COST (mseq);
619 /* If COST is big enough registers live in this matching sequence
620 should not be used as a link register. Also set ABSTRACTED_LENGTH
622 if (mseq->cost > seq_call_cost)
624 clear_regs_live_in_seq (&linkregs, mseq->insn,
625 mseq->abstracted_length);
626 if (mseq->abstracted_length > pseq->abstracted_length)
627 pseq->abstracted_length = mseq->abstracted_length;
631 /* Modify ABSTRACTED_LENGTH of PSEQ if pattern sequence overlaps with one
632 of the matching sequences. */
633 for (mseq = pseq->matching_seqs; mseq; mseq = mseq->next_matching_seq)
636 for (i = 0; (i < pseq->abstracted_length) && (x != mseq->insn); i++)
637 x = prev_insn_in_block (x);
638 pseq->abstracted_length = i;
641 /* Compute the cost of pattern sequence. */
642 RECOMPUTE_COST (pseq);
644 /* No gain if COST is too small. */
645 if (pseq->cost <= seq_call_cost)
651 /* Ensure that no matching sequence is longer than the pattern sequence. */
652 for (mseq = pseq->matching_seqs; mseq; mseq = mseq->next_matching_seq)
654 if (mseq->abstracted_length > pseq->abstracted_length)
656 mseq->abstracted_length = pseq->abstracted_length;
657 RECOMPUTE_COST (mseq);
659 /* Once the length is stabilizing the gain can be calculated. */
660 if (mseq->cost > seq_call_cost)
661 pseq->gain += mseq->cost - seq_call_cost;
664 /* No need to do further work if there is no gain. */
668 /* Should not use registers live in the pattern sequence as link register.
670 clear_regs_live_in_seq (&linkregs, pseq->insn, pseq->abstracted_length);
672 /* Determine whether pattern sequence contains a call_insn. */
675 for (i = 0; i < pseq->abstracted_length; i++)
682 x = prev_insn_in_block (x);
685 /* Should not use a register as a link register if - it is a fixed
686 register, or - the sequence contains a call insn and the register is a
687 call used register, or - the register needs to be saved if used in a
688 function but was not used before (since saving it can invalidate already
689 computed frame pointer offsets), or - the register cannot be used as a
692 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
694 #ifdef REGNO_OK_FOR_INDIRECT_JUMP_P
695 || (!REGNO_OK_FOR_INDIRECT_JUMP_P (i, Pmode))
697 || (!ok_for_base_p_1 (i, Pmode, MEM, SCRATCH))
698 || (!reg_class_subset_p (REGNO_REG_CLASS (i),
699 base_reg_class (VOIDmode, MEM, SCRATCH)))
701 || (hascall && call_used_regs[i])
702 || (!call_used_regs[i] && !df_regs_ever_live_p (i)))
703 CLEAR_HARD_REG_BIT (linkregs, i);
705 /* Find an appropriate register to be used as the link register. */
706 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
707 if (TEST_HARD_REG_BIT (linkregs, i))
709 pseq->link_reg = gen_rtx_REG (Pmode, i);
713 /* Abstraction is not possible if no link register is available, so set
719 /* Deallocates memory occupied by PSEQ and its matching seqs. */
722 free_pattern_seq (pattern_seq pseq)
724 while (pseq->matching_seqs)
726 matching_seq mseq = pseq->matching_seqs;
727 pseq->matching_seqs = mseq->next_matching_seq;
734 /* Computes the gain for pattern sequences. Pattern sequences producing no gain
735 are deleted. The pattern sequence with the biggest gain is moved to the first
736 place of PATTERN_SEQS. */
739 recompute_gain (void)
745 for (pseq = &pattern_seqs; *pseq;)
747 if ((*pseq)->gain <= 0)
748 recompute_gain_for_pattern_seq (*pseq);
750 if ((*pseq)->gain > 0)
752 if ((*pseq)->gain > maxgain)
754 pattern_seq temp = *pseq;
755 (*pseq) = temp->next_pattern_seq;
756 temp->next_pattern_seq = pattern_seqs;
758 maxgain = pattern_seqs->gain;
762 pseq = &(*pseq)->next_pattern_seq;
767 pattern_seq temp = *pseq;
768 *pseq = temp->next_pattern_seq;
769 free_pattern_seq (temp);
774 /* Updated those pattern sequences and matching sequences, which overlap with
775 the sequence given by INSN and LEN. Deletes sequences shrinking below a
779 erase_from_pattern_seqs (rtx insn, int len)
789 for (pseq = &pattern_seqs; *pseq;)
793 for (x = (*pseq)->insn; x && (x != insn);
794 x = prev_insn_in_block (x))
797 pcost += compute_rtx_cost (x);
800 if (pcost <= seq_call_cost)
802 pattern_seq temp = *pseq;
803 *pseq = temp->next_pattern_seq;
804 free_pattern_seq (temp);
808 for (mseq = &(*pseq)->matching_seqs; *mseq;)
812 for (x = (*mseq)->insn;
813 x && (x != insn) && (mlen < plen)
814 && (mlen < (*mseq)->matching_length);
815 x = prev_insn_in_block (x))
818 mcost += compute_rtx_cost (x);
821 if (mcost <= seq_call_cost)
823 matching_seq temp = *mseq;
824 *mseq = temp->next_matching_seq;
826 /* Set to 0 to force gain recomputation. */
831 if (mlen < (*mseq)->matching_length)
833 (*mseq)->cost = mcost;
834 (*mseq)->matching_length = mlen;
835 /* Set to 0 to force gain recomputation. */
838 mseq = &(*mseq)->next_matching_seq;
842 pseq = &(*pseq)->next_pattern_seq;
847 insn = prev_insn_in_block (insn);
851 /* Updates those pattern sequences and matching sequences, which overlap with
852 the pattern sequence with the biggest gain and its matching sequences. */
855 update_pattern_seqs (void)
857 pattern_seq bestpseq;
860 bestpseq = pattern_seqs;
861 pattern_seqs = bestpseq->next_pattern_seq;
863 for (mseq = bestpseq->matching_seqs; mseq; mseq = mseq->next_matching_seq)
864 if (mseq->cost > seq_call_cost)
865 erase_from_pattern_seqs (mseq->insn, mseq->abstracted_length);
866 erase_from_pattern_seqs (bestpseq->insn, bestpseq->abstracted_length);
868 bestpseq->next_pattern_seq = pattern_seqs;
869 pattern_seqs = bestpseq;
872 /* Groups together those matching sequences of the best pattern sequence, which
873 have the same ABSTRACTED_LENGTH and puts these groups in ascending order.
874 SEQ_BLOCKS contains the result. */
877 determine_seq_blocks (void)
883 /* Initialize SEQ_BLOCKS to empty. */
886 /* Process all matching sequences. */
887 for (mseq = &pattern_seqs->matching_seqs; *mseq;)
889 /* Deal only with matching sequences being long enough. */
890 if ((*mseq)->cost <= seq_call_cost)
892 mseq = &(*mseq)->next_matching_seq;
896 /* Ensure that SB contains a seq_block with the appropriate length.
897 Insert a new seq_block if necessary. */
898 if (!seq_blocks || ((*mseq)->abstracted_length < seq_blocks->length))
900 sb = (seq_block) xmalloc (sizeof (struct seq_block_def));
901 sb->length = (*mseq)->abstracted_length;
902 sb->label = NULL_RTX;
903 sb->matching_seqs = 0;
904 sb->next_seq_block = seq_blocks;
909 for (sb = seq_blocks; sb; sb = sb->next_seq_block)
911 if ((*mseq)->abstracted_length == sb->length)
913 if (!sb->next_seq_block
914 || ((*mseq)->abstracted_length <
915 sb->next_seq_block->length))
918 (seq_block) xmalloc (sizeof (struct seq_block_def));
919 temp->length = (*mseq)->abstracted_length;
920 temp->label = NULL_RTX;
921 temp->matching_seqs = 0;
922 temp->next_seq_block = sb->next_seq_block;
923 sb->next_seq_block = temp;
928 /* Remove the matching sequence from the linked list of the pattern
929 sequence and link it to SB. */
931 *mseq = m->next_matching_seq;
932 m->next_matching_seq = sb->matching_seqs;
933 sb->matching_seqs = m;
937 /* Builds a symbol_ref for LABEL. */
940 gen_symbol_ref_rtx_for_label (rtx label)
945 ASM_GENERATE_INTERNAL_LABEL (name, "L", CODE_LABEL_NUMBER (label));
946 sym = gen_rtx_SYMBOL_REF (Pmode, ggc_strdup (name));
947 SYMBOL_REF_FLAGS (sym) = SYMBOL_FLAG_LOCAL;
951 /* Ensures that INSN is the last insn in its block and returns the block label
952 of the next block. */
955 block_label_after (rtx insn)
957 basic_block bb = BLOCK_FOR_INSN (insn);
958 if ((insn == BB_END (bb)) && (bb->next_bb != EXIT_BLOCK_PTR))
959 return block_label (bb->next_bb);
961 return block_label (split_block (bb, insn)->dest);
964 /* Ensures that the last insns of the best pattern and its matching sequences
965 are the last insns in their block. Additionally, extends the live set at the
966 end of the pattern sequence with the live sets at the end of the matching
970 split_blocks_after_seqs (void)
975 block_label_after (pattern_seqs->insn);
976 for (sb = seq_blocks; sb; sb = sb->next_seq_block)
978 for (mseq = sb->matching_seqs; mseq; mseq = mseq->next_matching_seq)
980 block_label_after (mseq->insn);
981 IOR_REG_SET (df_get_live_out (BLOCK_FOR_INSN (pattern_seqs->insn)),
982 df_get_live_out (BLOCK_FOR_INSN (mseq->insn)));
987 /* Splits the best pattern sequence according to SEQ_BLOCKS. Emits pseudo-call
988 and -return insns before and after the sequence. */
991 split_pattern_seq (void)
995 rtx retlabel, retjmp, saveinsn;
999 insn = pattern_seqs->insn;
1000 bb = BLOCK_FOR_INSN (insn);
1002 /* Get the label after the sequence. This will be the return address. The
1003 label will be referenced using a symbol_ref so protect it from
1005 retlabel = block_label_after (insn);
1006 LABEL_PRESERVE_P (retlabel) = 1;
1008 /* Emit an indirect jump via the link register after the sequence acting
1009 as the return insn. Also emit a barrier and update the basic block. */
1010 retjmp = emit_jump_insn_after (gen_indirect_jump (pattern_seqs->link_reg),
1012 emit_barrier_after (BB_END (bb));
1014 /* Replace all outgoing edges with a new one to the block of RETLABEL. */
1015 while (EDGE_COUNT (bb->succs) != 0)
1016 remove_edge (EDGE_SUCC (bb, 0));
1017 make_edge (bb, BLOCK_FOR_INSN (retlabel), EDGE_ABNORMAL);
1019 /* Split the sequence according to SEQ_BLOCKS and cache the label of the
1020 resulting basic blocks. */
1022 for (sb = seq_blocks; sb; sb = sb->next_seq_block)
1024 for (; i < sb->length; i++)
1025 insn = prev_insn_in_block (insn);
1027 sb->label = block_label (split_block (bb, insn)->dest);
1030 /* Emit an insn saving the return address to the link register before the
1032 saveinsn = emit_insn_after (gen_move_insn (pattern_seqs->link_reg,
1033 gen_symbol_ref_rtx_for_label
1034 (retlabel)), BB_END (bb));
1035 /* Update liveness info. */
1036 SET_REGNO_REG_SET (df_get_live_out (bb),
1037 REGNO (pattern_seqs->link_reg));
1040 /* Deletes the insns of the matching sequences of the best pattern sequence and
1041 replaces them with pseudo-calls to the pattern sequence. */
1044 erase_matching_seqs (void)
1050 rtx retlabel, saveinsn, callinsn;
1053 for (sb = seq_blocks; sb; sb = sb->next_seq_block)
1055 for (mseq = sb->matching_seqs; mseq; mseq = mseq->next_matching_seq)
1058 bb = BLOCK_FOR_INSN (insn);
1060 /* Get the label after the sequence. This will be the return
1061 address. The label will be referenced using a symbol_ref so
1062 protect it from deleting. */
1063 retlabel = block_label_after (insn);
1064 LABEL_PRESERVE_P (retlabel) = 1;
1066 /* Delete the insns of the sequence. */
1067 for (i = 0; i < sb->length; i++)
1068 insn = prev_insn_in_block (insn);
1069 delete_basic_block (split_block (bb, insn)->dest);
1071 /* Emit an insn saving the return address to the link register
1072 before the deleted sequence. */
1073 saveinsn = emit_insn_after (gen_move_insn (pattern_seqs->link_reg,
1074 gen_symbol_ref_rtx_for_label
1077 BLOCK_FOR_INSN (saveinsn) = bb;
1079 /* Emit a jump to the appropriate part of the pattern sequence
1080 after the save insn. Also update the basic block. */
1081 callinsn = emit_jump_insn_after (gen_jump (sb->label), saveinsn);
1082 JUMP_LABEL (callinsn) = sb->label;
1083 LABEL_NUSES (sb->label)++;
1084 BLOCK_FOR_INSN (callinsn) = bb;
1085 BB_END (bb) = callinsn;
1087 /* Maintain control flow and liveness information. */
1088 SET_REGNO_REG_SET (df_get_live_out (bb),
1089 REGNO (pattern_seqs->link_reg));
1090 emit_barrier_after (BB_END (bb));
1091 make_single_succ_edge (bb, BLOCK_FOR_INSN (sb->label), 0);
1092 IOR_REG_SET (df_get_live_out (bb),
1093 df_get_live_in (BLOCK_FOR_INSN (sb->label)));
1095 make_edge (BLOCK_FOR_INSN (seq_blocks->label),
1096 BLOCK_FOR_INSN (retlabel), EDGE_ABNORMAL);
1101 /* Deallocates SEQ_BLOCKS and all the matching sequences. */
1104 free_seq_blocks (void)
1108 seq_block sb = seq_blocks;
1109 while (sb->matching_seqs)
1111 matching_seq mseq = sb->matching_seqs;
1112 sb->matching_seqs = mseq->next_matching_seq;
1115 seq_blocks = sb->next_seq_block;
1120 /* Transforms the best pattern sequence into a pseudo-function and its matching
1121 sequences to pseudo-calls. Afterwards the best pattern sequence is removed
1122 from PATTERN_SEQS. */
1125 abstract_best_seq (void)
1127 pattern_seq bestpseq;
1129 /* Do the abstraction. */
1130 determine_seq_blocks ();
1131 split_blocks_after_seqs ();
1132 split_pattern_seq ();
1133 erase_matching_seqs ();
1136 /* Record the usage of the link register. */
1137 df_set_regs_ever_live (REGNO (pattern_seqs->link_reg), true);
1139 /* Remove the best pattern sequence. */
1140 bestpseq = pattern_seqs;
1141 pattern_seqs = bestpseq->next_pattern_seq;
1142 free_pattern_seq (bestpseq);
1145 /* Prints info on the pattern sequences to the dump file. */
1148 dump_pattern_seqs (void)
1156 fprintf (dump_file, ";; Pattern sequences\n");
1157 for (pseq = pattern_seqs; pseq; pseq = pseq->next_pattern_seq)
1159 fprintf (dump_file, "Pattern sequence at insn %d matches sequences at",
1160 INSN_UID (pseq->insn));
1161 for (mseq = pseq->matching_seqs; mseq; mseq = mseq->next_matching_seq)
1163 fprintf (dump_file, " insn %d (length %d)", INSN_UID (mseq->insn),
1164 mseq->matching_length);
1165 if (mseq->next_matching_seq)
1166 fprintf (dump_file, ",");
1168 fprintf (dump_file, ".\n");
1170 fprintf (dump_file, "\n");
1173 /* Prints info on the best pattern sequence transformed in the ITER-th
1174 iteration to the dump file. */
1177 dump_best_pattern_seq (int iter)
1184 fprintf (dump_file, ";; Iteration %d\n", iter);
1186 "Best pattern sequence with %d gain is at insn %d (length %d).\n",
1187 pattern_seqs->gain, INSN_UID (pattern_seqs->insn),
1188 pattern_seqs->abstracted_length);
1189 fprintf (dump_file, "Matching sequences are at");
1190 for (mseq = pattern_seqs->matching_seqs; mseq;
1191 mseq = mseq->next_matching_seq)
1193 fprintf (dump_file, " insn %d (length %d)", INSN_UID (mseq->insn),
1194 mseq->abstracted_length);
1195 if (mseq->next_matching_seq)
1196 fprintf (dump_file, ",");
1198 fprintf (dump_file, ".\n");
1199 fprintf (dump_file, "Using reg %d as link register.\n\n",
1200 REGNO (pattern_seqs->link_reg));
1203 /* Htab hash function for hash_bucket_def structure. */
1206 htab_hash_bucket (const void *p)
1208 p_hash_bucket bucket = (p_hash_bucket) p;
1209 return bucket->hash;
1212 /* Htab equal function for hash_bucket_def structure. */
1215 htab_eq_bucket (const void *p0, const void *p1)
1217 return htab_hash_bucket (p0) == htab_hash_bucket (p1);
1220 /* Htab delete function for hash_bucket_def structure. */
1223 htab_del_bucket (void *p)
1225 p_hash_bucket bucket = (p_hash_bucket) p;
1227 if (bucket->seq_candidates)
1228 htab_delete (bucket->seq_candidates);
1233 /* Htab hash function for hash_bucket_def structure. */
1236 htab_hash_elem (const void *p)
1238 p_hash_elem elem = (p_hash_elem) p;
1239 return htab_hash_pointer (elem->insn);
1242 /* Htab equal function for hash_bucket_def structure. */
1245 htab_eq_elem (const void *p0, const void *p1)
1247 return htab_hash_elem (p0) == htab_hash_elem (p1);
1250 /* Htab delete function for hash_bucket_def structure. */
1253 htab_del_elem (void *p)
1255 p_hash_elem elem = (p_hash_elem) p;
1259 /* Creates a hash value for each sequence candidate and saves them
1263 fill_hash_bucket (void)
1268 p_hash_bucket bucket;
1269 struct hash_bucket_def tmp_bucket;
1271 unsigned long insn_idx;
1276 FOR_BB_INSNS_REVERSE (bb, insn)
1278 if (!ABSTRACTABLE_INSN_P (insn))
1281 /* Compute hash value for INSN. */
1282 tmp_bucket.hash = compute_hash (insn);
1284 /* Select the hash group. */
1285 bucket = htab_find (hash_buckets, &tmp_bucket);
1289 /* Create a new hash group. */
1290 bucket = (p_hash_bucket) xcalloc (1,
1291 sizeof (struct hash_bucket_def));
1292 bucket->hash = tmp_bucket.hash;
1293 bucket->seq_candidates = NULL;
1295 slot = htab_find_slot (hash_buckets, &tmp_bucket, INSERT);
1299 /* Create new list for storing sequence candidates. */
1300 if (!bucket->seq_candidates)
1301 bucket->seq_candidates = htab_create (HASH_INIT,
1306 elem = (p_hash_elem) xcalloc (1, sizeof (struct hash_elem_def));
1308 elem->idx = insn_idx;
1309 elem->length = get_attr_length (insn);
1311 /* Insert INSN into BUCKET hash bucket. */
1312 slot = htab_find_slot (bucket->seq_candidates, elem, INSERT);
1320 /* Computes the cost of calling sequence and the cost of return. */
1323 compute_init_costs (void)
1325 rtx rtx_jump, rtx_store, rtx_return, reg, label;
1332 label = block_label (bb);
1333 reg = gen_rtx_REG (Pmode, 0);
1335 /* Pattern for indirect jump. */
1336 rtx_jump = gen_indirect_jump (reg);
1338 /* Pattern for storing address. */
1339 rtx_store = gen_rtx_SET (VOIDmode, reg, gen_symbol_ref_rtx_for_label (label));
1341 /* Pattern for return insn. */
1342 rtx_return = gen_jump (label);
1344 /* The cost of jump. */
1345 seq_jump_cost = compute_rtx_cost (make_jump_insn_raw (rtx_jump));
1347 /* The cost of calling sequence. */
1348 seq_call_cost = seq_jump_cost + compute_rtx_cost (make_insn_raw (rtx_store));
1350 /* The cost of return. */
1351 seq_return_cost = compute_rtx_cost (make_jump_insn_raw (rtx_return));
1353 /* Simple heuristic for minimal sequence cost. */
1354 seq_call_cost = (int)(seq_call_cost * (double)SEQ_CALL_COST_MULTIPLIER);
1357 /* Finds equivalent insn sequences in the current function and retains only one
1358 instance of them which is turned into a pseudo-function. The additional
1359 copies are erased and replaced by pseudo-calls to the retained sequence. */
1365 df_set_flags (DF_LR_RUN_DCE);
1368 /* Create a hash list for COLLECT_PATTERN_SEQS. */
1369 hash_buckets = htab_create (HASH_INIT, htab_hash_bucket , htab_eq_bucket ,
1371 fill_hash_bucket ();
1373 /* Compute the common cost of abstraction. */
1374 compute_init_costs ();
1376 /* Build an initial set of pattern sequences from the current function. */
1377 collect_pattern_seqs ();
1378 dump_pattern_seqs ();
1380 /* Iterate until there are no sequences to abstract. */
1381 for (iter = 1;; iter++)
1383 /* Recompute gain for sequences if necessary and select sequence with
1388 dump_best_pattern_seq (iter);
1389 /* Update the cached info of the other sequences and force gain
1390 recomputation where needed. */
1391 update_pattern_seqs ();
1392 /* Turn best sequences into pseudo-functions and -calls. */
1393 abstract_best_seq ();
1396 /* Cleanup hash tables. */
1397 htab_delete (hash_buckets);
1400 /* The gate function for TREE_OPT_PASS. */
1403 gate_rtl_seqabstr (void)
1405 return flag_rtl_seqabstr;
1408 /* The entry point of the sequence abstraction algorithm. */
1411 rest_of_rtl_seqabstr (void)
1413 /* Abstract out common insn sequences. */
1418 struct tree_opt_pass pass_rtl_seqabstr = {
1419 "seqabstr", /* name */
1420 gate_rtl_seqabstr, /* gate */
1421 rest_of_rtl_seqabstr, /* execute */
1424 0, /* static_pass_number */
1425 TV_SEQABSTR, /* tv_id */
1426 0, /* properties_required */
1427 0, /* properties_provided */
1428 0, /* properties_destroyed */
1429 0, /* todo_flags_start */
1432 TODO_ggc_collect, /* todo_flags_finish */