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402209ff | 1 | /* Control flow optimization code for GNU compiler. |
818ab71a | 2 | Copyright (C) 1987-2016 Free Software Foundation, Inc. |
402209ff JH |
3 | |
4 | This file is part of GCC. | |
5 | ||
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 | |
9dcd6f09 | 8 | Software Foundation; either version 3, or (at your option) any later |
402209ff JH |
9 | version. |
10 | ||
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. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ | |
402209ff | 19 | |
1ea7e6ad | 20 | /* This file contains optimizer of the control flow. The main entry point is |
402209ff JH |
21 | cleanup_cfg. Following optimizations are performed: |
22 | ||
23 | - Unreachable blocks removal | |
d1a6adeb | 24 | - Edge forwarding (edge to the forwarder block is forwarded to its |
eaec9b3d | 25 | successor. Simplification of the branch instruction is performed by |
402209ff | 26 | underlying infrastructure so branch can be converted to simplejump or |
f5143c46 | 27 | eliminated). |
402209ff JH |
28 | - Cross jumping (tail merging) |
29 | - Conditional jump-around-simplejump simplification | |
30 | - Basic block merging. */ | |
31 | ||
32 | #include "config.h" | |
33 | #include "system.h" | |
4977bab6 | 34 | #include "coretypes.h" |
c7131fb2 | 35 | #include "backend.h" |
957060b5 | 36 | #include "target.h" |
402209ff | 37 | #include "rtl.h" |
957060b5 AM |
38 | #include "tree.h" |
39 | #include "cfghooks.h" | |
c7131fb2 | 40 | #include "df.h" |
957060b5 | 41 | #include "tm_p.h" |
402209ff | 42 | #include "insn-config.h" |
957060b5 | 43 | #include "emit-rtl.h" |
8ecba28a | 44 | #include "cselib.h" |
5f24e0dc | 45 | #include "params.h" |
ef330312 PB |
46 | #include "tree-pass.h" |
47 | #include "cfgloop.h" | |
60393bbc AM |
48 | #include "cfgrtl.h" |
49 | #include "cfganal.h" | |
50 | #include "cfgbuild.h" | |
51 | #include "cfgcleanup.h" | |
c1e3e2d9 | 52 | #include "dce.h" |
7d817ebc | 53 | #include "dbgcnt.h" |
a2250fe9 | 54 | #include "rtl-iter.h" |
402209ff | 55 | |
2dd2d53e | 56 | #define FORWARDER_BLOCK_P(BB) ((BB)->flags & BB_FORWARDER_BLOCK) |
c22cacf3 | 57 | |
7cf240d5 JH |
58 | /* Set to true when we are running first pass of try_optimize_cfg loop. */ |
59 | static bool first_pass; | |
c1e3e2d9 | 60 | |
073a8998 | 61 | /* Set to true if crossjumps occurred in the latest run of try_optimize_cfg. */ |
c1e3e2d9 SB |
62 | static bool crossjumps_occured; |
63 | ||
4ec5d4f5 BS |
64 | /* Set to true if we couldn't run an optimization due to stale liveness |
65 | information; we should run df_analyze to enable more opportunities. */ | |
66 | static bool block_was_dirty; | |
67 | ||
bf22920b | 68 | static bool try_crossjump_to_edge (int, edge, edge, enum replace_direction); |
d329e058 | 69 | static bool try_crossjump_bb (int, basic_block); |
c2fc5456 | 70 | static bool outgoing_edges_match (int, basic_block, basic_block); |
da5477a9 | 71 | static enum replace_direction old_insns_match_p (int, rtx_insn *, rtx_insn *); |
d329e058 | 72 | |
d329e058 AJ |
73 | static void merge_blocks_move_predecessor_nojumps (basic_block, basic_block); |
74 | static void merge_blocks_move_successor_nojumps (basic_block, basic_block); | |
d329e058 AJ |
75 | static bool try_optimize_cfg (int); |
76 | static bool try_simplify_condjump (basic_block); | |
77 | static bool try_forward_edges (int, basic_block); | |
6fb5fa3c | 78 | static edge thread_jump (edge, basic_block); |
d329e058 AJ |
79 | static bool mark_effect (rtx, bitmap); |
80 | static void notice_new_block (basic_block); | |
81 | static void update_forwarder_flag (basic_block); | |
c2fc5456 | 82 | static void merge_memattrs (rtx, rtx); |
635559ab JH |
83 | \f |
84 | /* Set flags for newly created block. */ | |
85 | ||
86 | static void | |
d329e058 | 87 | notice_new_block (basic_block bb) |
635559ab JH |
88 | { |
89 | if (!bb) | |
90 | return; | |
5f0d2358 | 91 | |
635559ab | 92 | if (forwarder_block_p (bb)) |
2dd2d53e | 93 | bb->flags |= BB_FORWARDER_BLOCK; |
635559ab JH |
94 | } |
95 | ||
96 | /* Recompute forwarder flag after block has been modified. */ | |
97 | ||
98 | static void | |
d329e058 | 99 | update_forwarder_flag (basic_block bb) |
635559ab JH |
100 | { |
101 | if (forwarder_block_p (bb)) | |
2dd2d53e | 102 | bb->flags |= BB_FORWARDER_BLOCK; |
635559ab | 103 | else |
2dd2d53e | 104 | bb->flags &= ~BB_FORWARDER_BLOCK; |
635559ab | 105 | } |
402209ff JH |
106 | \f |
107 | /* Simplify a conditional jump around an unconditional jump. | |
108 | Return true if something changed. */ | |
109 | ||
110 | static bool | |
d329e058 | 111 | try_simplify_condjump (basic_block cbranch_block) |
402209ff JH |
112 | { |
113 | basic_block jump_block, jump_dest_block, cbranch_dest_block; | |
114 | edge cbranch_jump_edge, cbranch_fallthru_edge; | |
da5477a9 | 115 | rtx_insn *cbranch_insn; |
402209ff JH |
116 | |
117 | /* Verify that there are exactly two successors. */ | |
628f6a4e | 118 | if (EDGE_COUNT (cbranch_block->succs) != 2) |
402209ff JH |
119 | return false; |
120 | ||
121 | /* Verify that we've got a normal conditional branch at the end | |
122 | of the block. */ | |
a813c111 | 123 | cbranch_insn = BB_END (cbranch_block); |
402209ff JH |
124 | if (!any_condjump_p (cbranch_insn)) |
125 | return false; | |
126 | ||
127 | cbranch_fallthru_edge = FALLTHRU_EDGE (cbranch_block); | |
128 | cbranch_jump_edge = BRANCH_EDGE (cbranch_block); | |
129 | ||
130 | /* The next block must not have multiple predecessors, must not | |
131 | be the last block in the function, and must contain just the | |
132 | unconditional jump. */ | |
133 | jump_block = cbranch_fallthru_edge->dest; | |
c5cbcccf | 134 | if (!single_pred_p (jump_block) |
fefa31b5 | 135 | || jump_block->next_bb == EXIT_BLOCK_PTR_FOR_FN (cfun) |
635559ab | 136 | || !FORWARDER_BLOCK_P (jump_block)) |
402209ff | 137 | return false; |
c5cbcccf | 138 | jump_dest_block = single_succ (jump_block); |
402209ff | 139 | |
750054a2 CT |
140 | /* If we are partitioning hot/cold basic blocks, we don't want to |
141 | mess up unconditional or indirect jumps that cross between hot | |
c22cacf3 | 142 | and cold sections. |
8e8d5162 CT |
143 | |
144 | Basic block partitioning may result in some jumps that appear to | |
c22cacf3 MS |
145 | be optimizable (or blocks that appear to be mergeable), but which really |
146 | must be left untouched (they are required to make it safely across | |
147 | partition boundaries). See the comments at the top of | |
8e8d5162 | 148 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
750054a2 | 149 | |
87c8b4be CT |
150 | if (BB_PARTITION (jump_block) != BB_PARTITION (jump_dest_block) |
151 | || (cbranch_jump_edge->flags & EDGE_CROSSING)) | |
750054a2 CT |
152 | return false; |
153 | ||
402209ff JH |
154 | /* The conditional branch must target the block after the |
155 | unconditional branch. */ | |
156 | cbranch_dest_block = cbranch_jump_edge->dest; | |
157 | ||
fefa31b5 | 158 | if (cbranch_dest_block == EXIT_BLOCK_PTR_FOR_FN (cfun) |
2f52c531 | 159 | || !can_fallthru (jump_block, cbranch_dest_block)) |
402209ff JH |
160 | return false; |
161 | ||
ca6c03ca | 162 | /* Invert the conditional branch. */ |
1476d1bd MM |
163 | if (!invert_jump (as_a <rtx_jump_insn *> (cbranch_insn), |
164 | block_label (jump_dest_block), 0)) | |
ca6c03ca | 165 | return false; |
402209ff | 166 | |
c263766c RH |
167 | if (dump_file) |
168 | fprintf (dump_file, "Simplifying condjump %i around jump %i\n", | |
a813c111 | 169 | INSN_UID (cbranch_insn), INSN_UID (BB_END (jump_block))); |
402209ff JH |
170 | |
171 | /* Success. Update the CFG to match. Note that after this point | |
172 | the edge variable names appear backwards; the redirection is done | |
173 | this way to preserve edge profile data. */ | |
174 | cbranch_jump_edge = redirect_edge_succ_nodup (cbranch_jump_edge, | |
175 | cbranch_dest_block); | |
176 | cbranch_fallthru_edge = redirect_edge_succ_nodup (cbranch_fallthru_edge, | |
177 | jump_dest_block); | |
178 | cbranch_jump_edge->flags |= EDGE_FALLTHRU; | |
179 | cbranch_fallthru_edge->flags &= ~EDGE_FALLTHRU; | |
b446e5a2 | 180 | update_br_prob_note (cbranch_block); |
402209ff JH |
181 | |
182 | /* Delete the block with the unconditional jump, and clean up the mess. */ | |
f470c378 ZD |
183 | delete_basic_block (jump_block); |
184 | tidy_fallthru_edge (cbranch_jump_edge); | |
261139ce | 185 | update_forwarder_flag (cbranch_block); |
402209ff JH |
186 | |
187 | return true; | |
188 | } | |
189 | \f | |
8ecba28a JH |
190 | /* Attempt to prove that operation is NOOP using CSElib or mark the effect |
191 | on register. Used by jump threading. */ | |
5f0d2358 | 192 | |
8ecba28a | 193 | static bool |
d329e058 | 194 | mark_effect (rtx exp, regset nonequal) |
8ecba28a | 195 | { |
9f16e871 | 196 | rtx dest; |
8ecba28a JH |
197 | switch (GET_CODE (exp)) |
198 | { | |
199 | /* In case we do clobber the register, mark it as equal, as we know the | |
c22cacf3 | 200 | value is dead so it don't have to match. */ |
f87c27b4 | 201 | case CLOBBER: |
07a737f3 RS |
202 | dest = XEXP (exp, 0); |
203 | if (REG_P (dest)) | |
204 | bitmap_clear_range (nonequal, REGNO (dest), REG_NREGS (dest)); | |
f87c27b4 | 205 | return false; |
5f0d2358 | 206 | |
f87c27b4 KH |
207 | case SET: |
208 | if (rtx_equal_for_cselib_p (SET_DEST (exp), SET_SRC (exp))) | |
8ecba28a | 209 | return false; |
f87c27b4 KH |
210 | dest = SET_DEST (exp); |
211 | if (dest == pc_rtx) | |
8ecba28a | 212 | return false; |
f87c27b4 KH |
213 | if (!REG_P (dest)) |
214 | return true; | |
07a737f3 | 215 | bitmap_set_range (nonequal, REGNO (dest), REG_NREGS (dest)); |
f87c27b4 KH |
216 | return false; |
217 | ||
218 | default: | |
219 | return false; | |
8ecba28a JH |
220 | } |
221 | } | |
fe477d8b | 222 | |
a2250fe9 RS |
223 | /* Return true if X contains a register in NONEQUAL. */ |
224 | static bool | |
225 | mentions_nonequal_regs (const_rtx x, regset nonequal) | |
fe477d8b | 226 | { |
a2250fe9 RS |
227 | subrtx_iterator::array_type array; |
228 | FOR_EACH_SUBRTX (iter, array, x, NONCONST) | |
fe477d8b | 229 | { |
a2250fe9 RS |
230 | const_rtx x = *iter; |
231 | if (REG_P (x)) | |
fe477d8b | 232 | { |
53d1bae9 RS |
233 | unsigned int end_regno = END_REGNO (x); |
234 | for (unsigned int regno = REGNO (x); regno < end_regno; ++regno) | |
235 | if (REGNO_REG_SET_P (nonequal, regno)) | |
236 | return true; | |
fe477d8b JH |
237 | } |
238 | } | |
a2250fe9 | 239 | return false; |
fe477d8b | 240 | } |
a2250fe9 | 241 | |
8ecba28a | 242 | /* Attempt to prove that the basic block B will have no side effects and |
95bd1dd7 | 243 | always continues in the same edge if reached via E. Return the edge |
8ecba28a JH |
244 | if exist, NULL otherwise. */ |
245 | ||
246 | static edge | |
6fb5fa3c | 247 | thread_jump (edge e, basic_block b) |
8ecba28a | 248 | { |
da5477a9 DM |
249 | rtx set1, set2, cond1, cond2; |
250 | rtx_insn *insn; | |
8ecba28a JH |
251 | enum rtx_code code1, code2, reversed_code2; |
252 | bool reverse1 = false; | |
3cd8c58a | 253 | unsigned i; |
8ecba28a JH |
254 | regset nonequal; |
255 | bool failed = false; | |
a2041967 | 256 | reg_set_iterator rsi; |
8ecba28a | 257 | |
2dd2d53e | 258 | if (b->flags & BB_NONTHREADABLE_BLOCK) |
1540f9eb JH |
259 | return NULL; |
260 | ||
8ecba28a JH |
261 | /* At the moment, we do handle only conditional jumps, but later we may |
262 | want to extend this code to tablejumps and others. */ | |
628f6a4e | 263 | if (EDGE_COUNT (e->src->succs) != 2) |
8ecba28a | 264 | return NULL; |
628f6a4e | 265 | if (EDGE_COUNT (b->succs) != 2) |
1540f9eb | 266 | { |
2dd2d53e | 267 | b->flags |= BB_NONTHREADABLE_BLOCK; |
1540f9eb JH |
268 | return NULL; |
269 | } | |
8ecba28a JH |
270 | |
271 | /* Second branch must end with onlyjump, as we will eliminate the jump. */ | |
a813c111 | 272 | if (!any_condjump_p (BB_END (e->src))) |
8ecba28a | 273 | return NULL; |
f87c27b4 | 274 | |
a813c111 | 275 | if (!any_condjump_p (BB_END (b)) || !onlyjump_p (BB_END (b))) |
1540f9eb | 276 | { |
2dd2d53e | 277 | b->flags |= BB_NONTHREADABLE_BLOCK; |
1540f9eb JH |
278 | return NULL; |
279 | } | |
8ecba28a | 280 | |
a813c111 SB |
281 | set1 = pc_set (BB_END (e->src)); |
282 | set2 = pc_set (BB_END (b)); | |
8ecba28a | 283 | if (((e->flags & EDGE_FALLTHRU) != 0) |
68f3f6f1 | 284 | != (XEXP (SET_SRC (set1), 1) == pc_rtx)) |
8ecba28a JH |
285 | reverse1 = true; |
286 | ||
287 | cond1 = XEXP (SET_SRC (set1), 0); | |
288 | cond2 = XEXP (SET_SRC (set2), 0); | |
289 | if (reverse1) | |
a813c111 | 290 | code1 = reversed_comparison_code (cond1, BB_END (e->src)); |
8ecba28a JH |
291 | else |
292 | code1 = GET_CODE (cond1); | |
293 | ||
294 | code2 = GET_CODE (cond2); | |
a813c111 | 295 | reversed_code2 = reversed_comparison_code (cond2, BB_END (b)); |
8ecba28a JH |
296 | |
297 | if (!comparison_dominates_p (code1, code2) | |
298 | && !comparison_dominates_p (code1, reversed_code2)) | |
299 | return NULL; | |
300 | ||
301 | /* Ensure that the comparison operators are equivalent. | |
95bd1dd7 | 302 | ??? This is far too pessimistic. We should allow swapped operands, |
8ecba28a JH |
303 | different CCmodes, or for example comparisons for interval, that |
304 | dominate even when operands are not equivalent. */ | |
305 | if (!rtx_equal_p (XEXP (cond1, 0), XEXP (cond2, 0)) | |
306 | || !rtx_equal_p (XEXP (cond1, 1), XEXP (cond2, 1))) | |
307 | return NULL; | |
308 | ||
309 | /* Short circuit cases where block B contains some side effects, as we can't | |
310 | safely bypass it. */ | |
a813c111 | 311 | for (insn = NEXT_INSN (BB_HEAD (b)); insn != NEXT_INSN (BB_END (b)); |
8ecba28a JH |
312 | insn = NEXT_INSN (insn)) |
313 | if (INSN_P (insn) && side_effects_p (PATTERN (insn))) | |
1540f9eb | 314 | { |
2dd2d53e | 315 | b->flags |= BB_NONTHREADABLE_BLOCK; |
1540f9eb JH |
316 | return NULL; |
317 | } | |
8ecba28a | 318 | |
457eeaae | 319 | cselib_init (0); |
8ecba28a JH |
320 | |
321 | /* First process all values computed in the source basic block. */ | |
3cd8c58a NS |
322 | for (insn = NEXT_INSN (BB_HEAD (e->src)); |
323 | insn != NEXT_INSN (BB_END (e->src)); | |
8ecba28a JH |
324 | insn = NEXT_INSN (insn)) |
325 | if (INSN_P (insn)) | |
326 | cselib_process_insn (insn); | |
327 | ||
8bdbfff5 | 328 | nonequal = BITMAP_ALLOC (NULL); |
8ecba28a | 329 | CLEAR_REG_SET (nonequal); |
5f0d2358 | 330 | |
8ecba28a JH |
331 | /* Now assume that we've continued by the edge E to B and continue |
332 | processing as if it were same basic block. | |
8ecba28a | 333 | Our goal is to prove that whole block is an NOOP. */ |
5f0d2358 | 334 | |
3cd8c58a NS |
335 | for (insn = NEXT_INSN (BB_HEAD (b)); |
336 | insn != NEXT_INSN (BB_END (b)) && !failed; | |
8ecba28a | 337 | insn = NEXT_INSN (insn)) |
f87c27b4 KH |
338 | { |
339 | if (INSN_P (insn)) | |
340 | { | |
341 | rtx pat = PATTERN (insn); | |
342 | ||
343 | if (GET_CODE (pat) == PARALLEL) | |
344 | { | |
3cd8c58a | 345 | for (i = 0; i < (unsigned)XVECLEN (pat, 0); i++) |
f87c27b4 KH |
346 | failed |= mark_effect (XVECEXP (pat, 0, i), nonequal); |
347 | } | |
348 | else | |
349 | failed |= mark_effect (pat, nonequal); | |
350 | } | |
5f0d2358 | 351 | |
f87c27b4 KH |
352 | cselib_process_insn (insn); |
353 | } | |
8ecba28a JH |
354 | |
355 | /* Later we should clear nonequal of dead registers. So far we don't | |
356 | have life information in cfg_cleanup. */ | |
357 | if (failed) | |
1540f9eb | 358 | { |
2dd2d53e | 359 | b->flags |= BB_NONTHREADABLE_BLOCK; |
1540f9eb JH |
360 | goto failed_exit; |
361 | } | |
8ecba28a | 362 | |
fe477d8b JH |
363 | /* cond2 must not mention any register that is not equal to the |
364 | former block. */ | |
a2250fe9 | 365 | if (mentions_nonequal_regs (cond2, nonequal)) |
fe477d8b JH |
366 | goto failed_exit; |
367 | ||
a2041967 KH |
368 | EXECUTE_IF_SET_IN_REG_SET (nonequal, 0, i, rsi) |
369 | goto failed_exit; | |
8ecba28a | 370 | |
8bdbfff5 | 371 | BITMAP_FREE (nonequal); |
8ecba28a JH |
372 | cselib_finish (); |
373 | if ((comparison_dominates_p (code1, code2) != 0) | |
4deaa2f8 | 374 | != (XEXP (SET_SRC (set2), 1) == pc_rtx)) |
8ecba28a JH |
375 | return BRANCH_EDGE (b); |
376 | else | |
377 | return FALLTHRU_EDGE (b); | |
378 | ||
379 | failed_exit: | |
8bdbfff5 | 380 | BITMAP_FREE (nonequal); |
8ecba28a JH |
381 | cselib_finish (); |
382 | return NULL; | |
383 | } | |
384 | \f | |
402209ff | 385 | /* Attempt to forward edges leaving basic block B. |
eaec9b3d | 386 | Return true if successful. */ |
402209ff JH |
387 | |
388 | static bool | |
d329e058 | 389 | try_forward_edges (int mode, basic_block b) |
402209ff JH |
390 | { |
391 | bool changed = false; | |
628f6a4e BE |
392 | edge_iterator ei; |
393 | edge e, *threaded_edges = NULL; | |
402209ff | 394 | |
750054a2 CT |
395 | /* If we are partitioning hot/cold basic blocks, we don't want to |
396 | mess up unconditional or indirect jumps that cross between hot | |
c22cacf3 MS |
397 | and cold sections. |
398 | ||
8e8d5162 | 399 | Basic block partitioning may result in some jumps that appear to |
fa10beec RW |
400 | be optimizable (or blocks that appear to be mergeable), but which really |
401 | must be left untouched (they are required to make it safely across | |
c22cacf3 | 402 | partition boundaries). See the comments at the top of |
8e8d5162 CT |
403 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
404 | ||
339ba33b | 405 | if (JUMP_P (BB_END (b)) && CROSSING_JUMP_P (BB_END (b))) |
750054a2 CT |
406 | return false; |
407 | ||
628f6a4e | 408 | for (ei = ei_start (b->succs); (e = ei_safe_edge (ei)); ) |
402209ff JH |
409 | { |
410 | basic_block target, first; | |
8a829274 EB |
411 | location_t goto_locus; |
412 | int counter; | |
8ecba28a | 413 | bool threaded = false; |
bcb3bc6d | 414 | int nthreaded_edges = 0; |
4ec5d4f5 | 415 | bool may_thread = first_pass || (b->flags & BB_MODIFIED) != 0; |
402209ff | 416 | |
402209ff JH |
417 | /* Skip complex edges because we don't know how to update them. |
418 | ||
c22cacf3 MS |
419 | Still handle fallthru edges, as we can succeed to forward fallthru |
420 | edge to the same place as the branch edge of conditional branch | |
421 | and turn conditional branch to an unconditional branch. */ | |
402209ff | 422 | if (e->flags & EDGE_COMPLEX) |
628f6a4e BE |
423 | { |
424 | ei_next (&ei); | |
425 | continue; | |
426 | } | |
402209ff JH |
427 | |
428 | target = first = e->dest; | |
24bd1a0b | 429 | counter = NUM_FIXED_BLOCKS; |
7241571e | 430 | goto_locus = e->goto_locus; |
402209ff | 431 | |
9fb32434 | 432 | /* If we are partitioning hot/cold basic_blocks, we don't want to mess |
8e8d5162 CT |
433 | up jumps that cross between hot/cold sections. |
434 | ||
435 | Basic block partitioning may result in some jumps that appear | |
c22cacf3 MS |
436 | to be optimizable (or blocks that appear to be mergeable), but which |
437 | really must be left untouched (they are required to make it safely | |
8e8d5162 CT |
438 | across partition boundaries). See the comments at the top of |
439 | bb-reorder.c:partition_hot_cold_basic_blocks for complete | |
440 | details. */ | |
9fb32434 | 441 | |
fefa31b5 | 442 | if (first != EXIT_BLOCK_PTR_FOR_FN (cfun) |
339ba33b RS |
443 | && JUMP_P (BB_END (first)) |
444 | && CROSSING_JUMP_P (BB_END (first))) | |
3371a64f | 445 | return changed; |
9fb32434 | 446 | |
0cae8d31 | 447 | while (counter < n_basic_blocks_for_fn (cfun)) |
402209ff | 448 | { |
8ecba28a JH |
449 | basic_block new_target = NULL; |
450 | bool new_target_threaded = false; | |
4ec5d4f5 | 451 | may_thread |= (target->flags & BB_MODIFIED) != 0; |
8ecba28a JH |
452 | |
453 | if (FORWARDER_BLOCK_P (target) | |
c22cacf3 | 454 | && !(single_succ_edge (target)->flags & EDGE_CROSSING) |
fefa31b5 | 455 | && single_succ (target) != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
8ecba28a JH |
456 | { |
457 | /* Bypass trivial infinite loops. */ | |
c5cbcccf ZD |
458 | new_target = single_succ (target); |
459 | if (target == new_target) | |
0cae8d31 | 460 | counter = n_basic_blocks_for_fn (cfun); |
7241571e JJ |
461 | else if (!optimize) |
462 | { | |
463 | /* When not optimizing, ensure that edges or forwarder | |
464 | blocks with different locus are not optimized out. */ | |
8a829274 EB |
465 | location_t new_locus = single_succ_edge (target)->goto_locus; |
466 | location_t locus = goto_locus; | |
7241571e | 467 | |
ffa4602f EB |
468 | if (LOCATION_LOCUS (new_locus) != UNKNOWN_LOCATION |
469 | && LOCATION_LOCUS (locus) != UNKNOWN_LOCATION | |
5368224f | 470 | && new_locus != locus) |
50a36e42 EB |
471 | new_target = NULL; |
472 | else | |
7241571e | 473 | { |
ffa4602f | 474 | if (LOCATION_LOCUS (new_locus) != UNKNOWN_LOCATION) |
50a36e42 | 475 | locus = new_locus; |
7241571e | 476 | |
da5477a9 | 477 | rtx_insn *last = BB_END (target); |
11321111 AO |
478 | if (DEBUG_INSN_P (last)) |
479 | last = prev_nondebug_insn (last); | |
ffa4602f EB |
480 | if (last && INSN_P (last)) |
481 | new_locus = INSN_LOCATION (last); | |
482 | else | |
483 | new_locus = UNKNOWN_LOCATION; | |
11321111 | 484 | |
ffa4602f EB |
485 | if (LOCATION_LOCUS (new_locus) != UNKNOWN_LOCATION |
486 | && LOCATION_LOCUS (locus) != UNKNOWN_LOCATION | |
5368224f | 487 | && new_locus != locus) |
50a36e42 EB |
488 | new_target = NULL; |
489 | else | |
490 | { | |
ffa4602f | 491 | if (LOCATION_LOCUS (new_locus) != UNKNOWN_LOCATION) |
50a36e42 EB |
492 | locus = new_locus; |
493 | ||
494 | goto_locus = locus; | |
495 | } | |
7241571e JJ |
496 | } |
497 | } | |
8ecba28a | 498 | } |
5f0d2358 | 499 | |
8ecba28a JH |
500 | /* Allow to thread only over one edge at time to simplify updating |
501 | of probabilities. */ | |
7cf240d5 | 502 | else if ((mode & CLEANUP_THREADING) && may_thread) |
8ecba28a | 503 | { |
6fb5fa3c | 504 | edge t = thread_jump (e, target); |
1c570418 | 505 | if (t) |
8ecba28a | 506 | { |
bcb3bc6d | 507 | if (!threaded_edges) |
0cae8d31 DM |
508 | threaded_edges = XNEWVEC (edge, |
509 | n_basic_blocks_for_fn (cfun)); | |
3b3b1e32 RH |
510 | else |
511 | { | |
512 | int i; | |
513 | ||
514 | /* Detect an infinite loop across blocks not | |
515 | including the start block. */ | |
516 | for (i = 0; i < nthreaded_edges; ++i) | |
517 | if (threaded_edges[i] == t) | |
518 | break; | |
519 | if (i < nthreaded_edges) | |
b90e45ae | 520 | { |
0cae8d31 | 521 | counter = n_basic_blocks_for_fn (cfun); |
b90e45ae JH |
522 | break; |
523 | } | |
3b3b1e32 RH |
524 | } |
525 | ||
526 | /* Detect an infinite loop across the start block. */ | |
527 | if (t->dest == b) | |
528 | break; | |
529 | ||
0cae8d31 DM |
530 | gcc_assert (nthreaded_edges |
531 | < (n_basic_blocks_for_fn (cfun) | |
532 | - NUM_FIXED_BLOCKS)); | |
1c570418 | 533 | threaded_edges[nthreaded_edges++] = t; |
3b3b1e32 RH |
534 | |
535 | new_target = t->dest; | |
536 | new_target_threaded = true; | |
8ecba28a JH |
537 | } |
538 | } | |
5f0d2358 | 539 | |
8ecba28a JH |
540 | if (!new_target) |
541 | break; | |
402209ff | 542 | |
8ecba28a JH |
543 | counter++; |
544 | target = new_target; | |
545 | threaded |= new_target_threaded; | |
f87c27b4 | 546 | } |
402209ff | 547 | |
0cae8d31 | 548 | if (counter >= n_basic_blocks_for_fn (cfun)) |
402209ff | 549 | { |
c263766c RH |
550 | if (dump_file) |
551 | fprintf (dump_file, "Infinite loop in BB %i.\n", | |
0b17ab2f | 552 | target->index); |
402209ff JH |
553 | } |
554 | else if (target == first) | |
555 | ; /* We didn't do anything. */ | |
556 | else | |
557 | { | |
558 | /* Save the values now, as the edge may get removed. */ | |
559 | gcov_type edge_count = e->count; | |
560 | int edge_probability = e->probability; | |
8ecba28a | 561 | int edge_frequency; |
1c570418 | 562 | int n = 0; |
402209ff | 563 | |
7241571e JJ |
564 | e->goto_locus = goto_locus; |
565 | ||
6ee3c8e4 | 566 | /* Don't force if target is exit block. */ |
fefa31b5 | 567 | if (threaded && target != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
402209ff | 568 | { |
8ecba28a | 569 | notice_new_block (redirect_edge_and_branch_force (e, target)); |
c263766c RH |
570 | if (dump_file) |
571 | fprintf (dump_file, "Conditionals threaded.\n"); | |
402209ff | 572 | } |
8ecba28a | 573 | else if (!redirect_edge_and_branch (e, target)) |
402209ff | 574 | { |
c263766c RH |
575 | if (dump_file) |
576 | fprintf (dump_file, | |
5f0d2358 | 577 | "Forwarding edge %i->%i to %i failed.\n", |
0b17ab2f | 578 | b->index, e->dest->index, target->index); |
628f6a4e | 579 | ei_next (&ei); |
8ecba28a | 580 | continue; |
402209ff | 581 | } |
5f0d2358 | 582 | |
8ecba28a JH |
583 | /* We successfully forwarded the edge. Now update profile |
584 | data: for each edge we traversed in the chain, remove | |
585 | the original edge's execution count. */ | |
8ddb5a29 | 586 | edge_frequency = apply_probability (b->frequency, edge_probability); |
8ecba28a | 587 | |
8ecba28a JH |
588 | do |
589 | { | |
590 | edge t; | |
5f0d2358 | 591 | |
c5cbcccf | 592 | if (!single_succ_p (first)) |
3b3b1e32 | 593 | { |
341c100f | 594 | gcc_assert (n < nthreaded_edges); |
3b3b1e32 | 595 | t = threaded_edges [n++]; |
341c100f | 596 | gcc_assert (t->src == first); |
15db5571 JH |
597 | update_bb_profile_for_threading (first, edge_frequency, |
598 | edge_count, t); | |
b446e5a2 | 599 | update_br_prob_note (first); |
3b3b1e32 | 600 | } |
8ecba28a | 601 | else |
bcb3bc6d | 602 | { |
15db5571 JH |
603 | first->count -= edge_count; |
604 | if (first->count < 0) | |
605 | first->count = 0; | |
606 | first->frequency -= edge_frequency; | |
607 | if (first->frequency < 0) | |
608 | first->frequency = 0; | |
bcb3bc6d JH |
609 | /* It is possible that as the result of |
610 | threading we've removed edge as it is | |
611 | threaded to the fallthru edge. Avoid | |
612 | getting out of sync. */ | |
613 | if (n < nthreaded_edges | |
614 | && first == threaded_edges [n]->src) | |
615 | n++; | |
c5cbcccf | 616 | t = single_succ_edge (first); |
f87c27b4 | 617 | } |
5f0d2358 | 618 | |
b446e5a2 JH |
619 | t->count -= edge_count; |
620 | if (t->count < 0) | |
621 | t->count = 0; | |
8ecba28a JH |
622 | first = t->dest; |
623 | } | |
624 | while (first != target); | |
625 | ||
626 | changed = true; | |
628f6a4e | 627 | continue; |
402209ff | 628 | } |
628f6a4e | 629 | ei_next (&ei); |
402209ff JH |
630 | } |
631 | ||
04695783 | 632 | free (threaded_edges); |
402209ff JH |
633 | return changed; |
634 | } | |
635 | \f | |
402209ff JH |
636 | |
637 | /* Blocks A and B are to be merged into a single block. A has no incoming | |
638 | fallthru edge, so it can be moved before B without adding or modifying | |
639 | any jumps (aside from the jump from A to B). */ | |
640 | ||
4262e623 | 641 | static void |
d329e058 | 642 | merge_blocks_move_predecessor_nojumps (basic_block a, basic_block b) |
402209ff | 643 | { |
da5477a9 | 644 | rtx_insn *barrier; |
402209ff | 645 | |
750054a2 CT |
646 | /* If we are partitioning hot/cold basic blocks, we don't want to |
647 | mess up unconditional or indirect jumps that cross between hot | |
8e8d5162 | 648 | and cold sections. |
c22cacf3 | 649 | |
8e8d5162 | 650 | Basic block partitioning may result in some jumps that appear to |
c22cacf3 MS |
651 | be optimizable (or blocks that appear to be mergeable), but which really |
652 | must be left untouched (they are required to make it safely across | |
653 | partition boundaries). See the comments at the top of | |
8e8d5162 CT |
654 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
655 | ||
87c8b4be | 656 | if (BB_PARTITION (a) != BB_PARTITION (b)) |
750054a2 CT |
657 | return; |
658 | ||
a813c111 | 659 | barrier = next_nonnote_insn (BB_END (a)); |
341c100f | 660 | gcc_assert (BARRIER_P (barrier)); |
53c17031 | 661 | delete_insn (barrier); |
402209ff | 662 | |
402209ff | 663 | /* Scramble the insn chain. */ |
a813c111 SB |
664 | if (BB_END (a) != PREV_INSN (BB_HEAD (b))) |
665 | reorder_insns_nobb (BB_HEAD (a), BB_END (a), PREV_INSN (BB_HEAD (b))); | |
6fb5fa3c | 666 | df_set_bb_dirty (a); |
402209ff | 667 | |
c263766c RH |
668 | if (dump_file) |
669 | fprintf (dump_file, "Moved block %d before %d and merged.\n", | |
0b17ab2f | 670 | a->index, b->index); |
402209ff | 671 | |
bf77398c | 672 | /* Swap the records for the two blocks around. */ |
402209ff | 673 | |
918ed612 ZD |
674 | unlink_block (a); |
675 | link_block (a, b->prev_bb); | |
676 | ||
402209ff | 677 | /* Now blocks A and B are contiguous. Merge them. */ |
bc35512f | 678 | merge_blocks (a, b); |
402209ff JH |
679 | } |
680 | ||
681 | /* Blocks A and B are to be merged into a single block. B has no outgoing | |
682 | fallthru edge, so it can be moved after A without adding or modifying | |
683 | any jumps (aside from the jump from A to B). */ | |
684 | ||
4262e623 | 685 | static void |
d329e058 | 686 | merge_blocks_move_successor_nojumps (basic_block a, basic_block b) |
402209ff | 687 | { |
da5477a9 | 688 | rtx_insn *barrier, *real_b_end; |
8942ee0f DM |
689 | rtx label; |
690 | rtx_jump_table_data *table; | |
402209ff | 691 | |
750054a2 CT |
692 | /* If we are partitioning hot/cold basic blocks, we don't want to |
693 | mess up unconditional or indirect jumps that cross between hot | |
c22cacf3 MS |
694 | and cold sections. |
695 | ||
8e8d5162 | 696 | Basic block partitioning may result in some jumps that appear to |
c22cacf3 MS |
697 | be optimizable (or blocks that appear to be mergeable), but which really |
698 | must be left untouched (they are required to make it safely across | |
699 | partition boundaries). See the comments at the top of | |
8e8d5162 CT |
700 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
701 | ||
87c8b4be | 702 | if (BB_PARTITION (a) != BB_PARTITION (b)) |
750054a2 CT |
703 | return; |
704 | ||
a813c111 | 705 | real_b_end = BB_END (b); |
402209ff | 706 | |
ee735eef JZ |
707 | /* If there is a jump table following block B temporarily add the jump table |
708 | to block B so that it will also be moved to the correct location. */ | |
a813c111 SB |
709 | if (tablejump_p (BB_END (b), &label, &table) |
710 | && prev_active_insn (label) == BB_END (b)) | |
402209ff | 711 | { |
1130d5e3 | 712 | BB_END (b) = table; |
402209ff JH |
713 | } |
714 | ||
715 | /* There had better have been a barrier there. Delete it. */ | |
a813c111 | 716 | barrier = NEXT_INSN (BB_END (b)); |
4b4bf941 | 717 | if (barrier && BARRIER_P (barrier)) |
53c17031 | 718 | delete_insn (barrier); |
402209ff | 719 | |
402209ff JH |
720 | |
721 | /* Scramble the insn chain. */ | |
a813c111 | 722 | reorder_insns_nobb (BB_HEAD (b), BB_END (b), BB_END (a)); |
402209ff | 723 | |
f62ce55b | 724 | /* Restore the real end of b. */ |
1130d5e3 | 725 | BB_END (b) = real_b_end; |
f62ce55b | 726 | |
c263766c RH |
727 | if (dump_file) |
728 | fprintf (dump_file, "Moved block %d after %d and merged.\n", | |
0b17ab2f | 729 | b->index, a->index); |
2150ad33 RH |
730 | |
731 | /* Now blocks A and B are contiguous. Merge them. */ | |
bc35512f | 732 | merge_blocks (a, b); |
402209ff JH |
733 | } |
734 | ||
735 | /* Attempt to merge basic blocks that are potentially non-adjacent. | |
ec3ae3da JH |
736 | Return NULL iff the attempt failed, otherwise return basic block |
737 | where cleanup_cfg should continue. Because the merging commonly | |
738 | moves basic block away or introduces another optimization | |
e0bb17a8 | 739 | possibility, return basic block just before B so cleanup_cfg don't |
ec3ae3da JH |
740 | need to iterate. |
741 | ||
742 | It may be good idea to return basic block before C in the case | |
743 | C has been moved after B and originally appeared earlier in the | |
4d6922ee | 744 | insn sequence, but we have no information available about the |
ec3ae3da JH |
745 | relative ordering of these two. Hopefully it is not too common. */ |
746 | ||
747 | static basic_block | |
bc35512f | 748 | merge_blocks_move (edge e, basic_block b, basic_block c, int mode) |
402209ff | 749 | { |
ec3ae3da | 750 | basic_block next; |
402209ff | 751 | |
750054a2 CT |
752 | /* If we are partitioning hot/cold basic blocks, we don't want to |
753 | mess up unconditional or indirect jumps that cross between hot | |
c22cacf3 MS |
754 | and cold sections. |
755 | ||
8e8d5162 | 756 | Basic block partitioning may result in some jumps that appear to |
c22cacf3 MS |
757 | be optimizable (or blocks that appear to be mergeable), but which really |
758 | must be left untouched (they are required to make it safely across | |
759 | partition boundaries). See the comments at the top of | |
8e8d5162 CT |
760 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
761 | ||
87c8b4be | 762 | if (BB_PARTITION (b) != BB_PARTITION (c)) |
750054a2 | 763 | return NULL; |
c22cacf3 | 764 | |
402209ff JH |
765 | /* If B has a fallthru edge to C, no need to move anything. */ |
766 | if (e->flags & EDGE_FALLTHRU) | |
767 | { | |
0b17ab2f | 768 | int b_index = b->index, c_index = c->index; |
7d776ee2 RG |
769 | |
770 | /* Protect the loop latches. */ | |
771 | if (current_loops && c->loop_father->latch == c) | |
772 | return NULL; | |
773 | ||
bc35512f | 774 | merge_blocks (b, c); |
635559ab | 775 | update_forwarder_flag (b); |
402209ff | 776 | |
c263766c RH |
777 | if (dump_file) |
778 | fprintf (dump_file, "Merged %d and %d without moving.\n", | |
f87c27b4 | 779 | b_index, c_index); |
402209ff | 780 | |
fefa31b5 | 781 | return b->prev_bb == ENTRY_BLOCK_PTR_FOR_FN (cfun) ? b : b->prev_bb; |
402209ff | 782 | } |
5f0d2358 | 783 | |
402209ff JH |
784 | /* Otherwise we will need to move code around. Do that only if expensive |
785 | transformations are allowed. */ | |
786 | else if (mode & CLEANUP_EXPENSIVE) | |
787 | { | |
4262e623 JH |
788 | edge tmp_edge, b_fallthru_edge; |
789 | bool c_has_outgoing_fallthru; | |
790 | bool b_has_incoming_fallthru; | |
402209ff JH |
791 | |
792 | /* Avoid overactive code motion, as the forwarder blocks should be | |
c22cacf3 | 793 | eliminated by edge redirection instead. One exception might have |
402209ff JH |
794 | been if B is a forwarder block and C has no fallthru edge, but |
795 | that should be cleaned up by bb-reorder instead. */ | |
635559ab | 796 | if (FORWARDER_BLOCK_P (b) || FORWARDER_BLOCK_P (c)) |
ec3ae3da | 797 | return NULL; |
402209ff JH |
798 | |
799 | /* We must make sure to not munge nesting of lexical blocks, | |
800 | and loop notes. This is done by squeezing out all the notes | |
801 | and leaving them there to lie. Not ideal, but functional. */ | |
802 | ||
0fd4b31d | 803 | tmp_edge = find_fallthru_edge (c->succs); |
402209ff | 804 | c_has_outgoing_fallthru = (tmp_edge != NULL); |
402209ff | 805 | |
0fd4b31d | 806 | tmp_edge = find_fallthru_edge (b->preds); |
402209ff | 807 | b_has_incoming_fallthru = (tmp_edge != NULL); |
4262e623 | 808 | b_fallthru_edge = tmp_edge; |
ec3ae3da | 809 | next = b->prev_bb; |
912b79e7 JH |
810 | if (next == c) |
811 | next = next->prev_bb; | |
4262e623 JH |
812 | |
813 | /* Otherwise, we're going to try to move C after B. If C does | |
814 | not have an outgoing fallthru, then it can be moved | |
815 | immediately after B without introducing or modifying jumps. */ | |
816 | if (! c_has_outgoing_fallthru) | |
817 | { | |
818 | merge_blocks_move_successor_nojumps (b, c); | |
fefa31b5 | 819 | return next == ENTRY_BLOCK_PTR_FOR_FN (cfun) ? next->next_bb : next; |
4262e623 | 820 | } |
402209ff JH |
821 | |
822 | /* If B does not have an incoming fallthru, then it can be moved | |
823 | immediately before C without introducing or modifying jumps. | |
824 | C cannot be the first block, so we do not have to worry about | |
825 | accessing a non-existent block. */ | |
402209ff | 826 | |
4262e623 JH |
827 | if (b_has_incoming_fallthru) |
828 | { | |
473fb060 | 829 | basic_block bb; |
5f0d2358 | 830 | |
fefa31b5 | 831 | if (b_fallthru_edge->src == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
ec3ae3da | 832 | return NULL; |
7dddfb65 JH |
833 | bb = force_nonfallthru (b_fallthru_edge); |
834 | if (bb) | |
835 | notice_new_block (bb); | |
4262e623 | 836 | } |
5f0d2358 | 837 | |
4262e623 | 838 | merge_blocks_move_predecessor_nojumps (b, c); |
fefa31b5 | 839 | return next == ENTRY_BLOCK_PTR_FOR_FN (cfun) ? next->next_bb : next; |
402209ff | 840 | } |
5f0d2358 | 841 | |
10d6c0d0 | 842 | return NULL; |
402209ff JH |
843 | } |
844 | \f | |
c2fc5456 R |
845 | |
846 | /* Removes the memory attributes of MEM expression | |
847 | if they are not equal. */ | |
848 | ||
893479de | 849 | static void |
c2fc5456 R |
850 | merge_memattrs (rtx x, rtx y) |
851 | { | |
852 | int i; | |
853 | int j; | |
854 | enum rtx_code code; | |
855 | const char *fmt; | |
856 | ||
857 | if (x == y) | |
858 | return; | |
859 | if (x == 0 || y == 0) | |
860 | return; | |
861 | ||
862 | code = GET_CODE (x); | |
863 | ||
864 | if (code != GET_CODE (y)) | |
865 | return; | |
866 | ||
867 | if (GET_MODE (x) != GET_MODE (y)) | |
868 | return; | |
869 | ||
96b3c03f | 870 | if (code == MEM && !mem_attrs_eq_p (MEM_ATTRS (x), MEM_ATTRS (y))) |
c2fc5456 R |
871 | { |
872 | if (! MEM_ATTRS (x)) | |
873 | MEM_ATTRS (y) = 0; | |
874 | else if (! MEM_ATTRS (y)) | |
875 | MEM_ATTRS (x) = 0; | |
c22cacf3 | 876 | else |
c2fc5456 | 877 | { |
f5541398 | 878 | HOST_WIDE_INT mem_size; |
c2fc5456 R |
879 | |
880 | if (MEM_ALIAS_SET (x) != MEM_ALIAS_SET (y)) | |
881 | { | |
882 | set_mem_alias_set (x, 0); | |
883 | set_mem_alias_set (y, 0); | |
884 | } | |
c22cacf3 | 885 | |
c2fc5456 R |
886 | if (! mem_expr_equal_p (MEM_EXPR (x), MEM_EXPR (y))) |
887 | { | |
888 | set_mem_expr (x, 0); | |
889 | set_mem_expr (y, 0); | |
527210c4 RS |
890 | clear_mem_offset (x); |
891 | clear_mem_offset (y); | |
c2fc5456 | 892 | } |
527210c4 RS |
893 | else if (MEM_OFFSET_KNOWN_P (x) != MEM_OFFSET_KNOWN_P (y) |
894 | || (MEM_OFFSET_KNOWN_P (x) | |
895 | && MEM_OFFSET (x) != MEM_OFFSET (y))) | |
c2fc5456 | 896 | { |
527210c4 RS |
897 | clear_mem_offset (x); |
898 | clear_mem_offset (y); | |
c2fc5456 | 899 | } |
c22cacf3 | 900 | |
f5541398 RS |
901 | if (MEM_SIZE_KNOWN_P (x) && MEM_SIZE_KNOWN_P (y)) |
902 | { | |
903 | mem_size = MAX (MEM_SIZE (x), MEM_SIZE (y)); | |
904 | set_mem_size (x, mem_size); | |
905 | set_mem_size (y, mem_size); | |
906 | } | |
c2fc5456 | 907 | else |
f5541398 RS |
908 | { |
909 | clear_mem_size (x); | |
910 | clear_mem_size (y); | |
911 | } | |
c2fc5456 R |
912 | |
913 | set_mem_align (x, MIN (MEM_ALIGN (x), MEM_ALIGN (y))); | |
914 | set_mem_align (y, MEM_ALIGN (x)); | |
915 | } | |
916 | } | |
84cf4ab6 JJ |
917 | if (code == MEM) |
918 | { | |
919 | if (MEM_READONLY_P (x) != MEM_READONLY_P (y)) | |
920 | { | |
921 | MEM_READONLY_P (x) = 0; | |
922 | MEM_READONLY_P (y) = 0; | |
923 | } | |
924 | if (MEM_NOTRAP_P (x) != MEM_NOTRAP_P (y)) | |
925 | { | |
926 | MEM_NOTRAP_P (x) = 0; | |
927 | MEM_NOTRAP_P (y) = 0; | |
928 | } | |
929 | if (MEM_VOLATILE_P (x) != MEM_VOLATILE_P (y)) | |
930 | { | |
931 | MEM_VOLATILE_P (x) = 1; | |
932 | MEM_VOLATILE_P (y) = 1; | |
933 | } | |
934 | } | |
c22cacf3 | 935 | |
c2fc5456 R |
936 | fmt = GET_RTX_FORMAT (code); |
937 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
938 | { | |
939 | switch (fmt[i]) | |
940 | { | |
941 | case 'E': | |
942 | /* Two vectors must have the same length. */ | |
943 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
944 | return; | |
945 | ||
946 | for (j = 0; j < XVECLEN (x, i); j++) | |
947 | merge_memattrs (XVECEXP (x, i, j), XVECEXP (y, i, j)); | |
948 | ||
949 | break; | |
950 | ||
951 | case 'e': | |
952 | merge_memattrs (XEXP (x, i), XEXP (y, i)); | |
953 | } | |
954 | } | |
955 | return; | |
956 | } | |
957 | ||
958 | ||
472c95f5 TV |
959 | /* Checks if patterns P1 and P2 are equivalent, apart from the possibly |
960 | different single sets S1 and S2. */ | |
c2fc5456 R |
961 | |
962 | static bool | |
472c95f5 TV |
963 | equal_different_set_p (rtx p1, rtx s1, rtx p2, rtx s2) |
964 | { | |
965 | int i; | |
966 | rtx e1, e2; | |
967 | ||
968 | if (p1 == s1 && p2 == s2) | |
969 | return true; | |
970 | ||
971 | if (GET_CODE (p1) != PARALLEL || GET_CODE (p2) != PARALLEL) | |
972 | return false; | |
973 | ||
974 | if (XVECLEN (p1, 0) != XVECLEN (p2, 0)) | |
975 | return false; | |
976 | ||
977 | for (i = 0; i < XVECLEN (p1, 0); i++) | |
978 | { | |
979 | e1 = XVECEXP (p1, 0, i); | |
980 | e2 = XVECEXP (p2, 0, i); | |
981 | if (e1 == s1 && e2 == s2) | |
982 | continue; | |
983 | if (reload_completed | |
984 | ? rtx_renumbered_equal_p (e1, e2) : rtx_equal_p (e1, e2)) | |
985 | continue; | |
986 | ||
21c0a521 | 987 | return false; |
472c95f5 TV |
988 | } |
989 | ||
990 | return true; | |
991 | } | |
992 | ||
3e87f2d6 SC |
993 | |
994 | /* NOTE1 is the REG_EQUAL note, if any, attached to an insn | |
995 | that is a single_set with a SET_SRC of SRC1. Similarly | |
996 | for NOTE2/SRC2. | |
997 | ||
998 | So effectively NOTE1/NOTE2 are an alternate form of | |
999 | SRC1/SRC2 respectively. | |
1000 | ||
1001 | Return nonzero if SRC1 or NOTE1 has the same constant | |
1002 | integer value as SRC2 or NOTE2. Else return zero. */ | |
1003 | static int | |
1004 | values_equal_p (rtx note1, rtx note2, rtx src1, rtx src2) | |
1005 | { | |
1006 | if (note1 | |
1007 | && note2 | |
1008 | && CONST_INT_P (XEXP (note1, 0)) | |
1009 | && rtx_equal_p (XEXP (note1, 0), XEXP (note2, 0))) | |
1010 | return 1; | |
1011 | ||
1012 | if (!note1 | |
1013 | && !note2 | |
1014 | && CONST_INT_P (src1) | |
1015 | && CONST_INT_P (src2) | |
1016 | && rtx_equal_p (src1, src2)) | |
1017 | return 1; | |
1018 | ||
1019 | if (note1 | |
1020 | && CONST_INT_P (src2) | |
1021 | && rtx_equal_p (XEXP (note1, 0), src2)) | |
1022 | return 1; | |
1023 | ||
1024 | if (note2 | |
1025 | && CONST_INT_P (src1) | |
1026 | && rtx_equal_p (XEXP (note2, 0), src1)) | |
1027 | return 1; | |
1028 | ||
1029 | return 0; | |
1030 | } | |
1031 | ||
472c95f5 TV |
1032 | /* Examine register notes on I1 and I2 and return: |
1033 | - dir_forward if I1 can be replaced by I2, or | |
1034 | - dir_backward if I2 can be replaced by I1, or | |
1035 | - dir_both if both are the case. */ | |
1036 | ||
1037 | static enum replace_direction | |
da5477a9 | 1038 | can_replace_by (rtx_insn *i1, rtx_insn *i2) |
472c95f5 TV |
1039 | { |
1040 | rtx s1, s2, d1, d2, src1, src2, note1, note2; | |
1041 | bool c1, c2; | |
1042 | ||
1043 | /* Check for 2 sets. */ | |
1044 | s1 = single_set (i1); | |
1045 | s2 = single_set (i2); | |
1046 | if (s1 == NULL_RTX || s2 == NULL_RTX) | |
1047 | return dir_none; | |
1048 | ||
1049 | /* Check that the 2 sets set the same dest. */ | |
1050 | d1 = SET_DEST (s1); | |
1051 | d2 = SET_DEST (s2); | |
1052 | if (!(reload_completed | |
1053 | ? rtx_renumbered_equal_p (d1, d2) : rtx_equal_p (d1, d2))) | |
1054 | return dir_none; | |
1055 | ||
1056 | /* Find identical req_equiv or reg_equal note, which implies that the 2 sets | |
1057 | set dest to the same value. */ | |
1058 | note1 = find_reg_equal_equiv_note (i1); | |
1059 | note2 = find_reg_equal_equiv_note (i2); | |
3e87f2d6 SC |
1060 | |
1061 | src1 = SET_SRC (s1); | |
1062 | src2 = SET_SRC (s2); | |
1063 | ||
1064 | if (!values_equal_p (note1, note2, src1, src2)) | |
472c95f5 TV |
1065 | return dir_none; |
1066 | ||
1067 | if (!equal_different_set_p (PATTERN (i1), s1, PATTERN (i2), s2)) | |
1068 | return dir_none; | |
1069 | ||
1070 | /* Although the 2 sets set dest to the same value, we cannot replace | |
1071 | (set (dest) (const_int)) | |
1072 | by | |
1073 | (set (dest) (reg)) | |
1074 | because we don't know if the reg is live and has the same value at the | |
1075 | location of replacement. */ | |
472c95f5 TV |
1076 | c1 = CONST_INT_P (src1); |
1077 | c2 = CONST_INT_P (src2); | |
1078 | if (c1 && c2) | |
1079 | return dir_both; | |
1080 | else if (c2) | |
1081 | return dir_forward; | |
1082 | else if (c1) | |
1083 | return dir_backward; | |
1084 | ||
1085 | return dir_none; | |
1086 | } | |
1087 | ||
1088 | /* Merges directions A and B. */ | |
1089 | ||
1090 | static enum replace_direction | |
1091 | merge_dir (enum replace_direction a, enum replace_direction b) | |
1092 | { | |
1093 | /* Implements the following table: | |
1094 | |bo fw bw no | |
1095 | ---+----------- | |
1096 | bo |bo fw bw no | |
1097 | fw |-- fw no no | |
1098 | bw |-- -- bw no | |
1099 | no |-- -- -- no. */ | |
1100 | ||
1101 | if (a == b) | |
1102 | return a; | |
1103 | ||
1104 | if (a == dir_both) | |
1105 | return b; | |
1106 | if (b == dir_both) | |
1107 | return a; | |
1108 | ||
1109 | return dir_none; | |
1110 | } | |
1111 | ||
1112 | /* Examine I1 and I2 and return: | |
1113 | - dir_forward if I1 can be replaced by I2, or | |
1114 | - dir_backward if I2 can be replaced by I1, or | |
1115 | - dir_both if both are the case. */ | |
1116 | ||
1117 | static enum replace_direction | |
da5477a9 | 1118 | old_insns_match_p (int mode ATTRIBUTE_UNUSED, rtx_insn *i1, rtx_insn *i2) |
c2fc5456 R |
1119 | { |
1120 | rtx p1, p2; | |
1121 | ||
1122 | /* Verify that I1 and I2 are equivalent. */ | |
1123 | if (GET_CODE (i1) != GET_CODE (i2)) | |
472c95f5 | 1124 | return dir_none; |
c2fc5456 | 1125 | |
ba21aba3 DD |
1126 | /* __builtin_unreachable() may lead to empty blocks (ending with |
1127 | NOTE_INSN_BASIC_BLOCK). They may be crossjumped. */ | |
1128 | if (NOTE_INSN_BASIC_BLOCK_P (i1) && NOTE_INSN_BASIC_BLOCK_P (i2)) | |
472c95f5 | 1129 | return dir_both; |
ba21aba3 | 1130 | |
9a08d230 RH |
1131 | /* ??? Do not allow cross-jumping between different stack levels. */ |
1132 | p1 = find_reg_note (i1, REG_ARGS_SIZE, NULL); | |
1133 | p2 = find_reg_note (i2, REG_ARGS_SIZE, NULL); | |
42aa5124 RH |
1134 | if (p1 && p2) |
1135 | { | |
1136 | p1 = XEXP (p1, 0); | |
1137 | p2 = XEXP (p2, 0); | |
1138 | if (!rtx_equal_p (p1, p2)) | |
1139 | return dir_none; | |
1140 | ||
1141 | /* ??? Worse, this adjustment had better be constant lest we | |
1142 | have differing incoming stack levels. */ | |
1143 | if (!frame_pointer_needed | |
1144 | && find_args_size_adjust (i1) == HOST_WIDE_INT_MIN) | |
1145 | return dir_none; | |
1146 | } | |
1147 | else if (p1 || p2) | |
9a08d230 RH |
1148 | return dir_none; |
1149 | ||
7752e522 | 1150 | p1 = PATTERN (i1); |
c2fc5456 R |
1151 | p2 = PATTERN (i2); |
1152 | ||
1153 | if (GET_CODE (p1) != GET_CODE (p2)) | |
472c95f5 | 1154 | return dir_none; |
c2fc5456 R |
1155 | |
1156 | /* If this is a CALL_INSN, compare register usage information. | |
1157 | If we don't check this on stack register machines, the two | |
1158 | CALL_INSNs might be merged leaving reg-stack.c with mismatching | |
1159 | numbers of stack registers in the same basic block. | |
1160 | If we don't check this on machines with delay slots, a delay slot may | |
1161 | be filled that clobbers a parameter expected by the subroutine. | |
1162 | ||
1163 | ??? We take the simple route for now and assume that if they're | |
31ce8a53 | 1164 | equal, they were constructed identically. |
c2fc5456 | 1165 | |
31ce8a53 BS |
1166 | Also check for identical exception regions. */ |
1167 | ||
1168 | if (CALL_P (i1)) | |
1169 | { | |
1170 | /* Ensure the same EH region. */ | |
1171 | rtx n1 = find_reg_note (i1, REG_EH_REGION, 0); | |
1172 | rtx n2 = find_reg_note (i2, REG_EH_REGION, 0); | |
1173 | ||
1174 | if (!n1 && n2) | |
472c95f5 | 1175 | return dir_none; |
31ce8a53 BS |
1176 | |
1177 | if (n1 && (!n2 || XEXP (n1, 0) != XEXP (n2, 0))) | |
472c95f5 | 1178 | return dir_none; |
31ce8a53 BS |
1179 | |
1180 | if (!rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1), | |
c22cacf3 | 1181 | CALL_INSN_FUNCTION_USAGE (i2)) |
31ce8a53 | 1182 | || SIBLING_CALL_P (i1) != SIBLING_CALL_P (i2)) |
472c95f5 | 1183 | return dir_none; |
68a9738a JJ |
1184 | |
1185 | /* For address sanitizer, never crossjump __asan_report_* builtins, | |
1186 | otherwise errors might be reported on incorrect lines. */ | |
de5a5fa1 | 1187 | if (flag_sanitize & SANITIZE_ADDRESS) |
68a9738a JJ |
1188 | { |
1189 | rtx call = get_call_rtx_from (i1); | |
1190 | if (call && GET_CODE (XEXP (XEXP (call, 0), 0)) == SYMBOL_REF) | |
1191 | { | |
1192 | rtx symbol = XEXP (XEXP (call, 0), 0); | |
1193 | if (SYMBOL_REF_DECL (symbol) | |
1194 | && TREE_CODE (SYMBOL_REF_DECL (symbol)) == FUNCTION_DECL) | |
1195 | { | |
1196 | if ((DECL_BUILT_IN_CLASS (SYMBOL_REF_DECL (symbol)) | |
1197 | == BUILT_IN_NORMAL) | |
1198 | && DECL_FUNCTION_CODE (SYMBOL_REF_DECL (symbol)) | |
1199 | >= BUILT_IN_ASAN_REPORT_LOAD1 | |
1200 | && DECL_FUNCTION_CODE (SYMBOL_REF_DECL (symbol)) | |
8946c29e | 1201 | <= BUILT_IN_ASAN_STOREN) |
68a9738a JJ |
1202 | return dir_none; |
1203 | } | |
1204 | } | |
1205 | } | |
31ce8a53 | 1206 | } |
c2fc5456 R |
1207 | |
1208 | #ifdef STACK_REGS | |
1209 | /* If cross_jump_death_matters is not 0, the insn's mode | |
1210 | indicates whether or not the insn contains any stack-like | |
1211 | regs. */ | |
1212 | ||
1213 | if ((mode & CLEANUP_POST_REGSTACK) && stack_regs_mentioned (i1)) | |
1214 | { | |
1215 | /* If register stack conversion has already been done, then | |
c22cacf3 MS |
1216 | death notes must also be compared before it is certain that |
1217 | the two instruction streams match. */ | |
c2fc5456 R |
1218 | |
1219 | rtx note; | |
1220 | HARD_REG_SET i1_regset, i2_regset; | |
1221 | ||
1222 | CLEAR_HARD_REG_SET (i1_regset); | |
1223 | CLEAR_HARD_REG_SET (i2_regset); | |
1224 | ||
1225 | for (note = REG_NOTES (i1); note; note = XEXP (note, 1)) | |
1226 | if (REG_NOTE_KIND (note) == REG_DEAD && STACK_REG_P (XEXP (note, 0))) | |
1227 | SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0))); | |
1228 | ||
1229 | for (note = REG_NOTES (i2); note; note = XEXP (note, 1)) | |
1230 | if (REG_NOTE_KIND (note) == REG_DEAD && STACK_REG_P (XEXP (note, 0))) | |
1231 | SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0))); | |
1232 | ||
56b138ae | 1233 | if (!hard_reg_set_equal_p (i1_regset, i2_regset)) |
472c95f5 | 1234 | return dir_none; |
c2fc5456 R |
1235 | } |
1236 | #endif | |
1237 | ||
1238 | if (reload_completed | |
1239 | ? rtx_renumbered_equal_p (p1, p2) : rtx_equal_p (p1, p2)) | |
472c95f5 | 1240 | return dir_both; |
c2fc5456 | 1241 | |
472c95f5 | 1242 | return can_replace_by (i1, i2); |
c2fc5456 R |
1243 | } |
1244 | \f | |
31ce8a53 BS |
1245 | /* When comparing insns I1 and I2 in flow_find_cross_jump or |
1246 | flow_find_head_matching_sequence, ensure the notes match. */ | |
1247 | ||
1248 | static void | |
da5477a9 | 1249 | merge_notes (rtx_insn *i1, rtx_insn *i2) |
31ce8a53 BS |
1250 | { |
1251 | /* If the merged insns have different REG_EQUAL notes, then | |
1252 | remove them. */ | |
1253 | rtx equiv1 = find_reg_equal_equiv_note (i1); | |
1254 | rtx equiv2 = find_reg_equal_equiv_note (i2); | |
1255 | ||
1256 | if (equiv1 && !equiv2) | |
1257 | remove_note (i1, equiv1); | |
1258 | else if (!equiv1 && equiv2) | |
1259 | remove_note (i2, equiv2); | |
1260 | else if (equiv1 && equiv2 | |
1261 | && !rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0))) | |
1262 | { | |
1263 | remove_note (i1, equiv1); | |
1264 | remove_note (i2, equiv2); | |
1265 | } | |
1266 | } | |
1267 | ||
823918ae TV |
1268 | /* Walks from I1 in BB1 backward till the next non-debug insn, and returns the |
1269 | resulting insn in I1, and the corresponding bb in BB1. At the head of a | |
1270 | bb, if there is a predecessor bb that reaches this bb via fallthru, and | |
1271 | FOLLOW_FALLTHRU, walks further in the predecessor bb and registers this in | |
1272 | DID_FALLTHRU. Otherwise, stops at the head of the bb. */ | |
1273 | ||
1274 | static void | |
da5477a9 | 1275 | walk_to_nondebug_insn (rtx_insn **i1, basic_block *bb1, bool follow_fallthru, |
823918ae TV |
1276 | bool *did_fallthru) |
1277 | { | |
1278 | edge fallthru; | |
1279 | ||
1280 | *did_fallthru = false; | |
1281 | ||
1282 | /* Ignore notes. */ | |
1283 | while (!NONDEBUG_INSN_P (*i1)) | |
1284 | { | |
1285 | if (*i1 != BB_HEAD (*bb1)) | |
1286 | { | |
1287 | *i1 = PREV_INSN (*i1); | |
1288 | continue; | |
1289 | } | |
1290 | ||
1291 | if (!follow_fallthru) | |
1292 | return; | |
1293 | ||
1294 | fallthru = find_fallthru_edge ((*bb1)->preds); | |
fefa31b5 | 1295 | if (!fallthru || fallthru->src == ENTRY_BLOCK_PTR_FOR_FN (cfun) |
823918ae TV |
1296 | || !single_succ_p (fallthru->src)) |
1297 | return; | |
1298 | ||
1299 | *bb1 = fallthru->src; | |
1300 | *i1 = BB_END (*bb1); | |
1301 | *did_fallthru = true; | |
1302 | } | |
1303 | } | |
1304 | ||
c2fc5456 | 1305 | /* Look through the insns at the end of BB1 and BB2 and find the longest |
472c95f5 TV |
1306 | sequence that are either equivalent, or allow forward or backward |
1307 | replacement. Store the first insns for that sequence in *F1 and *F2 and | |
1308 | return the sequence length. | |
1309 | ||
1310 | DIR_P indicates the allowed replacement direction on function entry, and | |
1311 | the actual replacement direction on function exit. If NULL, only equivalent | |
1312 | sequences are allowed. | |
c2fc5456 R |
1313 | |
1314 | To simplify callers of this function, if the blocks match exactly, | |
1315 | store the head of the blocks in *F1 and *F2. */ | |
1316 | ||
31ce8a53 | 1317 | int |
da5477a9 DM |
1318 | flow_find_cross_jump (basic_block bb1, basic_block bb2, rtx_insn **f1, |
1319 | rtx_insn **f2, enum replace_direction *dir_p) | |
c2fc5456 | 1320 | { |
da5477a9 | 1321 | rtx_insn *i1, *i2, *last1, *last2, *afterlast1, *afterlast2; |
c2fc5456 | 1322 | int ninsns = 0; |
472c95f5 | 1323 | enum replace_direction dir, last_dir, afterlast_dir; |
823918ae | 1324 | bool follow_fallthru, did_fallthru; |
472c95f5 TV |
1325 | |
1326 | if (dir_p) | |
1327 | dir = *dir_p; | |
1328 | else | |
1329 | dir = dir_both; | |
1330 | afterlast_dir = dir; | |
1331 | last_dir = afterlast_dir; | |
c2fc5456 R |
1332 | |
1333 | /* Skip simple jumps at the end of the blocks. Complex jumps still | |
1334 | need to be compared for equivalence, which we'll do below. */ | |
1335 | ||
1336 | i1 = BB_END (bb1); | |
da5477a9 | 1337 | last1 = afterlast1 = last2 = afterlast2 = NULL; |
c2fc5456 R |
1338 | if (onlyjump_p (i1) |
1339 | || (returnjump_p (i1) && !side_effects_p (PATTERN (i1)))) | |
1340 | { | |
1341 | last1 = i1; | |
1342 | i1 = PREV_INSN (i1); | |
1343 | } | |
1344 | ||
1345 | i2 = BB_END (bb2); | |
1346 | if (onlyjump_p (i2) | |
1347 | || (returnjump_p (i2) && !side_effects_p (PATTERN (i2)))) | |
1348 | { | |
1349 | last2 = i2; | |
a0cbe71e JJ |
1350 | /* Count everything except for unconditional jump as insn. |
1351 | Don't count any jumps if dir_p is NULL. */ | |
1352 | if (!simplejump_p (i2) && !returnjump_p (i2) && last1 && dir_p) | |
c2fc5456 R |
1353 | ninsns++; |
1354 | i2 = PREV_INSN (i2); | |
1355 | } | |
1356 | ||
1357 | while (true) | |
1358 | { | |
823918ae TV |
1359 | /* In the following example, we can replace all jumps to C by jumps to A. |
1360 | ||
1361 | This removes 4 duplicate insns. | |
1362 | [bb A] insn1 [bb C] insn1 | |
1363 | insn2 insn2 | |
1364 | [bb B] insn3 insn3 | |
1365 | insn4 insn4 | |
1366 | jump_insn jump_insn | |
1367 | ||
1368 | We could also replace all jumps to A by jumps to C, but that leaves B | |
1369 | alive, and removes only 2 duplicate insns. In a subsequent crossjump | |
1370 | step, all jumps to B would be replaced with jumps to the middle of C, | |
1371 | achieving the same result with more effort. | |
1372 | So we allow only the first possibility, which means that we don't allow | |
1373 | fallthru in the block that's being replaced. */ | |
1374 | ||
1375 | follow_fallthru = dir_p && dir != dir_forward; | |
1376 | walk_to_nondebug_insn (&i1, &bb1, follow_fallthru, &did_fallthru); | |
1377 | if (did_fallthru) | |
1378 | dir = dir_backward; | |
1379 | ||
1380 | follow_fallthru = dir_p && dir != dir_backward; | |
1381 | walk_to_nondebug_insn (&i2, &bb2, follow_fallthru, &did_fallthru); | |
1382 | if (did_fallthru) | |
1383 | dir = dir_forward; | |
c2fc5456 R |
1384 | |
1385 | if (i1 == BB_HEAD (bb1) || i2 == BB_HEAD (bb2)) | |
1386 | break; | |
1387 | ||
472c95f5 TV |
1388 | dir = merge_dir (dir, old_insns_match_p (0, i1, i2)); |
1389 | if (dir == dir_none || (!dir_p && dir != dir_both)) | |
c2fc5456 R |
1390 | break; |
1391 | ||
1392 | merge_memattrs (i1, i2); | |
1393 | ||
1394 | /* Don't begin a cross-jump with a NOTE insn. */ | |
1395 | if (INSN_P (i1)) | |
1396 | { | |
31ce8a53 | 1397 | merge_notes (i1, i2); |
c2fc5456 R |
1398 | |
1399 | afterlast1 = last1, afterlast2 = last2; | |
1400 | last1 = i1, last2 = i2; | |
472c95f5 TV |
1401 | afterlast_dir = last_dir; |
1402 | last_dir = dir; | |
a0cbe71e | 1403 | if (active_insn_p (i1)) |
2a562b0a | 1404 | ninsns++; |
c2fc5456 R |
1405 | } |
1406 | ||
1407 | i1 = PREV_INSN (i1); | |
1408 | i2 = PREV_INSN (i2); | |
1409 | } | |
1410 | ||
c2fc5456 R |
1411 | /* Don't allow the insn after a compare to be shared by |
1412 | cross-jumping unless the compare is also shared. */ | |
618f4073 TS |
1413 | if (HAVE_cc0 && ninsns && reg_mentioned_p (cc0_rtx, last1) |
1414 | && ! sets_cc0_p (last1)) | |
472c95f5 | 1415 | last1 = afterlast1, last2 = afterlast2, last_dir = afterlast_dir, ninsns--; |
c2fc5456 R |
1416 | |
1417 | /* Include preceding notes and labels in the cross-jump. One, | |
1418 | this may bring us to the head of the blocks as requested above. | |
1419 | Two, it keeps line number notes as matched as may be. */ | |
1420 | if (ninsns) | |
1421 | { | |
823918ae | 1422 | bb1 = BLOCK_FOR_INSN (last1); |
b5b8b0ac | 1423 | while (last1 != BB_HEAD (bb1) && !NONDEBUG_INSN_P (PREV_INSN (last1))) |
c2fc5456 R |
1424 | last1 = PREV_INSN (last1); |
1425 | ||
1426 | if (last1 != BB_HEAD (bb1) && LABEL_P (PREV_INSN (last1))) | |
1427 | last1 = PREV_INSN (last1); | |
1428 | ||
823918ae | 1429 | bb2 = BLOCK_FOR_INSN (last2); |
b5b8b0ac | 1430 | while (last2 != BB_HEAD (bb2) && !NONDEBUG_INSN_P (PREV_INSN (last2))) |
c2fc5456 R |
1431 | last2 = PREV_INSN (last2); |
1432 | ||
1433 | if (last2 != BB_HEAD (bb2) && LABEL_P (PREV_INSN (last2))) | |
1434 | last2 = PREV_INSN (last2); | |
1435 | ||
1436 | *f1 = last1; | |
1437 | *f2 = last2; | |
1438 | } | |
1439 | ||
472c95f5 TV |
1440 | if (dir_p) |
1441 | *dir_p = last_dir; | |
c2fc5456 R |
1442 | return ninsns; |
1443 | } | |
1444 | ||
31ce8a53 BS |
1445 | /* Like flow_find_cross_jump, except start looking for a matching sequence from |
1446 | the head of the two blocks. Do not include jumps at the end. | |
1447 | If STOP_AFTER is nonzero, stop after finding that many matching | |
b59e0455 JJ |
1448 | instructions. If STOP_AFTER is zero, count all INSN_P insns, if it is |
1449 | non-zero, only count active insns. */ | |
31ce8a53 BS |
1450 | |
1451 | int | |
da5477a9 DM |
1452 | flow_find_head_matching_sequence (basic_block bb1, basic_block bb2, rtx_insn **f1, |
1453 | rtx_insn **f2, int stop_after) | |
31ce8a53 | 1454 | { |
da5477a9 | 1455 | rtx_insn *i1, *i2, *last1, *last2, *beforelast1, *beforelast2; |
31ce8a53 BS |
1456 | int ninsns = 0; |
1457 | edge e; | |
1458 | edge_iterator ei; | |
1459 | int nehedges1 = 0, nehedges2 = 0; | |
1460 | ||
1461 | FOR_EACH_EDGE (e, ei, bb1->succs) | |
1462 | if (e->flags & EDGE_EH) | |
1463 | nehedges1++; | |
1464 | FOR_EACH_EDGE (e, ei, bb2->succs) | |
1465 | if (e->flags & EDGE_EH) | |
1466 | nehedges2++; | |
1467 | ||
1468 | i1 = BB_HEAD (bb1); | |
1469 | i2 = BB_HEAD (bb2); | |
da5477a9 | 1470 | last1 = beforelast1 = last2 = beforelast2 = NULL; |
31ce8a53 BS |
1471 | |
1472 | while (true) | |
1473 | { | |
4ec5d4f5 | 1474 | /* Ignore notes, except NOTE_INSN_EPILOGUE_BEG. */ |
31ce8a53 | 1475 | while (!NONDEBUG_INSN_P (i1) && i1 != BB_END (bb1)) |
4ec5d4f5 BS |
1476 | { |
1477 | if (NOTE_P (i1) && NOTE_KIND (i1) == NOTE_INSN_EPILOGUE_BEG) | |
1478 | break; | |
1479 | i1 = NEXT_INSN (i1); | |
1480 | } | |
31ce8a53 BS |
1481 | |
1482 | while (!NONDEBUG_INSN_P (i2) && i2 != BB_END (bb2)) | |
4ec5d4f5 BS |
1483 | { |
1484 | if (NOTE_P (i2) && NOTE_KIND (i2) == NOTE_INSN_EPILOGUE_BEG) | |
1485 | break; | |
1486 | i2 = NEXT_INSN (i2); | |
1487 | } | |
31ce8a53 | 1488 | |
662592e1 BS |
1489 | if ((i1 == BB_END (bb1) && !NONDEBUG_INSN_P (i1)) |
1490 | || (i2 == BB_END (bb2) && !NONDEBUG_INSN_P (i2))) | |
1491 | break; | |
1492 | ||
31ce8a53 BS |
1493 | if (NOTE_P (i1) || NOTE_P (i2) |
1494 | || JUMP_P (i1) || JUMP_P (i2)) | |
1495 | break; | |
1496 | ||
1497 | /* A sanity check to make sure we're not merging insns with different | |
1498 | effects on EH. If only one of them ends a basic block, it shouldn't | |
1499 | have an EH edge; if both end a basic block, there should be the same | |
1500 | number of EH edges. */ | |
1501 | if ((i1 == BB_END (bb1) && i2 != BB_END (bb2) | |
1502 | && nehedges1 > 0) | |
1503 | || (i2 == BB_END (bb2) && i1 != BB_END (bb1) | |
1504 | && nehedges2 > 0) | |
1505 | || (i1 == BB_END (bb1) && i2 == BB_END (bb2) | |
1506 | && nehedges1 != nehedges2)) | |
1507 | break; | |
1508 | ||
472c95f5 | 1509 | if (old_insns_match_p (0, i1, i2) != dir_both) |
31ce8a53 BS |
1510 | break; |
1511 | ||
1512 | merge_memattrs (i1, i2); | |
1513 | ||
1514 | /* Don't begin a cross-jump with a NOTE insn. */ | |
1515 | if (INSN_P (i1)) | |
1516 | { | |
1517 | merge_notes (i1, i2); | |
1518 | ||
1519 | beforelast1 = last1, beforelast2 = last2; | |
1520 | last1 = i1, last2 = i2; | |
b59e0455 | 1521 | if (!stop_after || active_insn_p (i1)) |
a0cbe71e | 1522 | ninsns++; |
31ce8a53 BS |
1523 | } |
1524 | ||
1525 | if (i1 == BB_END (bb1) || i2 == BB_END (bb2) | |
1526 | || (stop_after > 0 && ninsns == stop_after)) | |
1527 | break; | |
1528 | ||
1529 | i1 = NEXT_INSN (i1); | |
1530 | i2 = NEXT_INSN (i2); | |
1531 | } | |
1532 | ||
31ce8a53 BS |
1533 | /* Don't allow a compare to be shared by cross-jumping unless the insn |
1534 | after the compare is also shared. */ | |
618f4073 TS |
1535 | if (HAVE_cc0 && ninsns && reg_mentioned_p (cc0_rtx, last1) |
1536 | && sets_cc0_p (last1)) | |
31ce8a53 | 1537 | last1 = beforelast1, last2 = beforelast2, ninsns--; |
31ce8a53 BS |
1538 | |
1539 | if (ninsns) | |
1540 | { | |
1541 | *f1 = last1; | |
1542 | *f2 = last2; | |
1543 | } | |
1544 | ||
1545 | return ninsns; | |
1546 | } | |
1547 | ||
c2fc5456 R |
1548 | /* Return true iff outgoing edges of BB1 and BB2 match, together with |
1549 | the branch instruction. This means that if we commonize the control | |
1550 | flow before end of the basic block, the semantic remains unchanged. | |
402209ff JH |
1551 | |
1552 | We may assume that there exists one edge with a common destination. */ | |
1553 | ||
1554 | static bool | |
c2fc5456 | 1555 | outgoing_edges_match (int mode, basic_block bb1, basic_block bb2) |
402209ff | 1556 | { |
0dd0e980 JH |
1557 | int nehedges1 = 0, nehedges2 = 0; |
1558 | edge fallthru1 = 0, fallthru2 = 0; | |
1559 | edge e1, e2; | |
628f6a4e | 1560 | edge_iterator ei; |
0dd0e980 | 1561 | |
6626665f | 1562 | /* If we performed shrink-wrapping, edges to the exit block can |
484db665 BS |
1563 | only be distinguished for JUMP_INSNs. The two paths may differ in |
1564 | whether they went through the prologue. Sibcalls are fine, we know | |
1565 | that we either didn't need or inserted an epilogue before them. */ | |
1566 | if (crtl->shrink_wrapped | |
fefa31b5 DM |
1567 | && single_succ_p (bb1) |
1568 | && single_succ (bb1) == EXIT_BLOCK_PTR_FOR_FN (cfun) | |
484db665 BS |
1569 | && !JUMP_P (BB_END (bb1)) |
1570 | && !(CALL_P (BB_END (bb1)) && SIBLING_CALL_P (BB_END (bb1)))) | |
1571 | return false; | |
1572 | ||
c04cf67b RH |
1573 | /* If BB1 has only one successor, we may be looking at either an |
1574 | unconditional jump, or a fake edge to exit. */ | |
c5cbcccf ZD |
1575 | if (single_succ_p (bb1) |
1576 | && (single_succ_edge (bb1)->flags & (EDGE_COMPLEX | EDGE_FAKE)) == 0 | |
4b4bf941 | 1577 | && (!JUMP_P (BB_END (bb1)) || simplejump_p (BB_END (bb1)))) |
c5cbcccf ZD |
1578 | return (single_succ_p (bb2) |
1579 | && (single_succ_edge (bb2)->flags | |
1580 | & (EDGE_COMPLEX | EDGE_FAKE)) == 0 | |
4b4bf941 | 1581 | && (!JUMP_P (BB_END (bb2)) || simplejump_p (BB_END (bb2)))); |
402209ff JH |
1582 | |
1583 | /* Match conditional jumps - this may get tricky when fallthru and branch | |
1584 | edges are crossed. */ | |
628f6a4e | 1585 | if (EDGE_COUNT (bb1->succs) == 2 |
a813c111 SB |
1586 | && any_condjump_p (BB_END (bb1)) |
1587 | && onlyjump_p (BB_END (bb1))) | |
402209ff | 1588 | { |
c2fc5456 R |
1589 | edge b1, f1, b2, f2; |
1590 | bool reverse, match; | |
1591 | rtx set1, set2, cond1, cond2; | |
1592 | enum rtx_code code1, code2; | |
1593 | ||
628f6a4e | 1594 | if (EDGE_COUNT (bb2->succs) != 2 |
a813c111 SB |
1595 | || !any_condjump_p (BB_END (bb2)) |
1596 | || !onlyjump_p (BB_END (bb2))) | |
0a2ed1f1 | 1597 | return false; |
c2fc5456 R |
1598 | |
1599 | b1 = BRANCH_EDGE (bb1); | |
1600 | b2 = BRANCH_EDGE (bb2); | |
1601 | f1 = FALLTHRU_EDGE (bb1); | |
1602 | f2 = FALLTHRU_EDGE (bb2); | |
1603 | ||
1604 | /* Get around possible forwarders on fallthru edges. Other cases | |
c22cacf3 | 1605 | should be optimized out already. */ |
c2fc5456 R |
1606 | if (FORWARDER_BLOCK_P (f1->dest)) |
1607 | f1 = single_succ_edge (f1->dest); | |
1608 | ||
1609 | if (FORWARDER_BLOCK_P (f2->dest)) | |
1610 | f2 = single_succ_edge (f2->dest); | |
1611 | ||
1612 | /* To simplify use of this function, return false if there are | |
1613 | unneeded forwarder blocks. These will get eliminated later | |
1614 | during cleanup_cfg. */ | |
1615 | if (FORWARDER_BLOCK_P (f1->dest) | |
1616 | || FORWARDER_BLOCK_P (f2->dest) | |
1617 | || FORWARDER_BLOCK_P (b1->dest) | |
1618 | || FORWARDER_BLOCK_P (b2->dest)) | |
1619 | return false; | |
1620 | ||
1621 | if (f1->dest == f2->dest && b1->dest == b2->dest) | |
1622 | reverse = false; | |
1623 | else if (f1->dest == b2->dest && b1->dest == f2->dest) | |
1624 | reverse = true; | |
1625 | else | |
1626 | return false; | |
1627 | ||
1628 | set1 = pc_set (BB_END (bb1)); | |
1629 | set2 = pc_set (BB_END (bb2)); | |
1630 | if ((XEXP (SET_SRC (set1), 1) == pc_rtx) | |
1631 | != (XEXP (SET_SRC (set2), 1) == pc_rtx)) | |
1632 | reverse = !reverse; | |
1633 | ||
1634 | cond1 = XEXP (SET_SRC (set1), 0); | |
1635 | cond2 = XEXP (SET_SRC (set2), 0); | |
1636 | code1 = GET_CODE (cond1); | |
1637 | if (reverse) | |
1638 | code2 = reversed_comparison_code (cond2, BB_END (bb2)); | |
1639 | else | |
1640 | code2 = GET_CODE (cond2); | |
1641 | ||
1642 | if (code2 == UNKNOWN) | |
1643 | return false; | |
1644 | ||
1645 | /* Verify codes and operands match. */ | |
1646 | match = ((code1 == code2 | |
1647 | && rtx_renumbered_equal_p (XEXP (cond1, 0), XEXP (cond2, 0)) | |
1648 | && rtx_renumbered_equal_p (XEXP (cond1, 1), XEXP (cond2, 1))) | |
1649 | || (code1 == swap_condition (code2) | |
1650 | && rtx_renumbered_equal_p (XEXP (cond1, 1), | |
1651 | XEXP (cond2, 0)) | |
1652 | && rtx_renumbered_equal_p (XEXP (cond1, 0), | |
1653 | XEXP (cond2, 1)))); | |
1654 | ||
1655 | /* If we return true, we will join the blocks. Which means that | |
1656 | we will only have one branch prediction bit to work with. Thus | |
1657 | we require the existing branches to have probabilities that are | |
1658 | roughly similar. */ | |
1659 | if (match | |
efd8f750 JH |
1660 | && optimize_bb_for_speed_p (bb1) |
1661 | && optimize_bb_for_speed_p (bb2)) | |
c2fc5456 R |
1662 | { |
1663 | int prob2; | |
1664 | ||
1665 | if (b1->dest == b2->dest) | |
1666 | prob2 = b2->probability; | |
1667 | else | |
1668 | /* Do not use f2 probability as f2 may be forwarded. */ | |
1669 | prob2 = REG_BR_PROB_BASE - b2->probability; | |
1670 | ||
1671 | /* Fail if the difference in probabilities is greater than 50%. | |
1672 | This rules out two well-predicted branches with opposite | |
1673 | outcomes. */ | |
1674 | if (abs (b1->probability - prob2) > REG_BR_PROB_BASE / 2) | |
1675 | { | |
1676 | if (dump_file) | |
1677 | fprintf (dump_file, | |
1678 | "Outcomes of branch in bb %i and %i differ too much (%i %i)\n", | |
1679 | bb1->index, bb2->index, b1->probability, prob2); | |
1680 | ||
1681 | return false; | |
1682 | } | |
1683 | } | |
1684 | ||
1685 | if (dump_file && match) | |
1686 | fprintf (dump_file, "Conditionals in bb %i and %i match.\n", | |
1687 | bb1->index, bb2->index); | |
1688 | ||
1689 | return match; | |
402209ff JH |
1690 | } |
1691 | ||
09da1532 | 1692 | /* Generic case - we are seeing a computed jump, table jump or trapping |
0dd0e980 JH |
1693 | instruction. */ |
1694 | ||
39811184 JZ |
1695 | /* Check whether there are tablejumps in the end of BB1 and BB2. |
1696 | Return true if they are identical. */ | |
1697 | { | |
1698 | rtx label1, label2; | |
8942ee0f | 1699 | rtx_jump_table_data *table1, *table2; |
39811184 | 1700 | |
a813c111 SB |
1701 | if (tablejump_p (BB_END (bb1), &label1, &table1) |
1702 | && tablejump_p (BB_END (bb2), &label2, &table2) | |
39811184 JZ |
1703 | && GET_CODE (PATTERN (table1)) == GET_CODE (PATTERN (table2))) |
1704 | { | |
1705 | /* The labels should never be the same rtx. If they really are same | |
1706 | the jump tables are same too. So disable crossjumping of blocks BB1 | |
1707 | and BB2 because when deleting the common insns in the end of BB1 | |
6de9cd9a | 1708 | by delete_basic_block () the jump table would be deleted too. */ |
4af16369 | 1709 | /* If LABEL2 is referenced in BB1->END do not do anything |
39811184 JZ |
1710 | because we would loose information when replacing |
1711 | LABEL1 by LABEL2 and then LABEL2 by LABEL1 in BB1->END. */ | |
a813c111 | 1712 | if (label1 != label2 && !rtx_referenced_p (label2, BB_END (bb1))) |
39811184 JZ |
1713 | { |
1714 | /* Set IDENTICAL to true when the tables are identical. */ | |
1715 | bool identical = false; | |
1716 | rtx p1, p2; | |
1717 | ||
1718 | p1 = PATTERN (table1); | |
1719 | p2 = PATTERN (table2); | |
1720 | if (GET_CODE (p1) == ADDR_VEC && rtx_equal_p (p1, p2)) | |
1721 | { | |
1722 | identical = true; | |
1723 | } | |
1724 | else if (GET_CODE (p1) == ADDR_DIFF_VEC | |
1725 | && (XVECLEN (p1, 1) == XVECLEN (p2, 1)) | |
1726 | && rtx_equal_p (XEXP (p1, 2), XEXP (p2, 2)) | |
1727 | && rtx_equal_p (XEXP (p1, 3), XEXP (p2, 3))) | |
1728 | { | |
1729 | int i; | |
1730 | ||
1731 | identical = true; | |
1732 | for (i = XVECLEN (p1, 1) - 1; i >= 0 && identical; i--) | |
1733 | if (!rtx_equal_p (XVECEXP (p1, 1, i), XVECEXP (p2, 1, i))) | |
1734 | identical = false; | |
1735 | } | |
1736 | ||
c2fc5456 | 1737 | if (identical) |
39811184 | 1738 | { |
39811184 JZ |
1739 | bool match; |
1740 | ||
c2fc5456 | 1741 | /* Temporarily replace references to LABEL1 with LABEL2 |
39811184 | 1742 | in BB1->END so that we could compare the instructions. */ |
a2b7026c | 1743 | replace_label_in_insn (BB_END (bb1), label1, label2, false); |
39811184 | 1744 | |
472c95f5 TV |
1745 | match = (old_insns_match_p (mode, BB_END (bb1), BB_END (bb2)) |
1746 | == dir_both); | |
c263766c RH |
1747 | if (dump_file && match) |
1748 | fprintf (dump_file, | |
39811184 JZ |
1749 | "Tablejumps in bb %i and %i match.\n", |
1750 | bb1->index, bb2->index); | |
1751 | ||
c2fc5456 R |
1752 | /* Set the original label in BB1->END because when deleting |
1753 | a block whose end is a tablejump, the tablejump referenced | |
1754 | from the instruction is deleted too. */ | |
a2b7026c | 1755 | replace_label_in_insn (BB_END (bb1), label2, label1, false); |
c2fc5456 | 1756 | |
39811184 JZ |
1757 | return match; |
1758 | } | |
1759 | } | |
1760 | return false; | |
1761 | } | |
1762 | } | |
39811184 | 1763 | |
d41d6122 TJ |
1764 | /* Find the last non-debug non-note instruction in each bb, except |
1765 | stop when we see the NOTE_INSN_BASIC_BLOCK, as old_insns_match_p | |
1766 | handles that case specially. old_insns_match_p does not handle | |
1767 | other types of instruction notes. */ | |
da5477a9 DM |
1768 | rtx_insn *last1 = BB_END (bb1); |
1769 | rtx_insn *last2 = BB_END (bb2); | |
d41d6122 TJ |
1770 | while (!NOTE_INSN_BASIC_BLOCK_P (last1) && |
1771 | (DEBUG_INSN_P (last1) || NOTE_P (last1))) | |
1772 | last1 = PREV_INSN (last1); | |
1773 | while (!NOTE_INSN_BASIC_BLOCK_P (last2) && | |
1774 | (DEBUG_INSN_P (last2) || NOTE_P (last2))) | |
1775 | last2 = PREV_INSN (last2); | |
1776 | gcc_assert (last1 && last2); | |
1777 | ||
0dd0e980 | 1778 | /* First ensure that the instructions match. There may be many outgoing |
39811184 | 1779 | edges so this test is generally cheaper. */ |
206604dc | 1780 | if (old_insns_match_p (mode, last1, last2) != dir_both) |
0dd0e980 JH |
1781 | return false; |
1782 | ||
1783 | /* Search the outgoing edges, ensure that the counts do match, find possible | |
1784 | fallthru and exception handling edges since these needs more | |
1785 | validation. */ | |
628f6a4e BE |
1786 | if (EDGE_COUNT (bb1->succs) != EDGE_COUNT (bb2->succs)) |
1787 | return false; | |
1788 | ||
206604dc | 1789 | bool nonfakeedges = false; |
628f6a4e | 1790 | FOR_EACH_EDGE (e1, ei, bb1->succs) |
0dd0e980 | 1791 | { |
628f6a4e | 1792 | e2 = EDGE_SUCC (bb2, ei.index); |
c22cacf3 | 1793 | |
206604dc JJ |
1794 | if ((e1->flags & EDGE_FAKE) == 0) |
1795 | nonfakeedges = true; | |
1796 | ||
0dd0e980 JH |
1797 | if (e1->flags & EDGE_EH) |
1798 | nehedges1++; | |
5f0d2358 | 1799 | |
0dd0e980 JH |
1800 | if (e2->flags & EDGE_EH) |
1801 | nehedges2++; | |
5f0d2358 | 1802 | |
0dd0e980 JH |
1803 | if (e1->flags & EDGE_FALLTHRU) |
1804 | fallthru1 = e1; | |
1805 | if (e2->flags & EDGE_FALLTHRU) | |
1806 | fallthru2 = e2; | |
1807 | } | |
5f0d2358 | 1808 | |
0dd0e980 | 1809 | /* If number of edges of various types does not match, fail. */ |
628f6a4e | 1810 | if (nehedges1 != nehedges2 |
5f0d2358 | 1811 | || (fallthru1 != 0) != (fallthru2 != 0)) |
0dd0e980 JH |
1812 | return false; |
1813 | ||
206604dc JJ |
1814 | /* If !ACCUMULATE_OUTGOING_ARGS, bb1 (and bb2) have no successors |
1815 | and the last real insn doesn't have REG_ARGS_SIZE note, don't | |
1816 | attempt to optimize, as the two basic blocks might have different | |
1817 | REG_ARGS_SIZE depths. For noreturn calls and unconditional | |
1818 | traps there should be REG_ARG_SIZE notes, they could be missing | |
1819 | for __builtin_unreachable () uses though. */ | |
1820 | if (!nonfakeedges | |
1821 | && !ACCUMULATE_OUTGOING_ARGS | |
1822 | && (!INSN_P (last1) | |
1823 | || !find_reg_note (last1, REG_ARGS_SIZE, NULL))) | |
1824 | return false; | |
1825 | ||
0dd0e980 JH |
1826 | /* fallthru edges must be forwarded to the same destination. */ |
1827 | if (fallthru1) | |
1828 | { | |
1829 | basic_block d1 = (forwarder_block_p (fallthru1->dest) | |
c5cbcccf | 1830 | ? single_succ (fallthru1->dest): fallthru1->dest); |
0dd0e980 | 1831 | basic_block d2 = (forwarder_block_p (fallthru2->dest) |
c5cbcccf | 1832 | ? single_succ (fallthru2->dest): fallthru2->dest); |
5f0d2358 | 1833 | |
0dd0e980 JH |
1834 | if (d1 != d2) |
1835 | return false; | |
1836 | } | |
5f0d2358 | 1837 | |
5f77fbd4 JJ |
1838 | /* Ensure the same EH region. */ |
1839 | { | |
a813c111 SB |
1840 | rtx n1 = find_reg_note (BB_END (bb1), REG_EH_REGION, 0); |
1841 | rtx n2 = find_reg_note (BB_END (bb2), REG_EH_REGION, 0); | |
5f0d2358 | 1842 | |
5f77fbd4 JJ |
1843 | if (!n1 && n2) |
1844 | return false; | |
1845 | ||
1846 | if (n1 && (!n2 || XEXP (n1, 0) != XEXP (n2, 0))) | |
1847 | return false; | |
1848 | } | |
5f0d2358 | 1849 | |
38109dab GL |
1850 | /* The same checks as in try_crossjump_to_edge. It is required for RTL |
1851 | version of sequence abstraction. */ | |
1852 | FOR_EACH_EDGE (e1, ei, bb2->succs) | |
1853 | { | |
1854 | edge e2; | |
1855 | edge_iterator ei; | |
1856 | basic_block d1 = e1->dest; | |
1857 | ||
1858 | if (FORWARDER_BLOCK_P (d1)) | |
1859 | d1 = EDGE_SUCC (d1, 0)->dest; | |
1860 | ||
1861 | FOR_EACH_EDGE (e2, ei, bb1->succs) | |
1862 | { | |
1863 | basic_block d2 = e2->dest; | |
1864 | if (FORWARDER_BLOCK_P (d2)) | |
1865 | d2 = EDGE_SUCC (d2, 0)->dest; | |
1866 | if (d1 == d2) | |
1867 | break; | |
1868 | } | |
1869 | ||
1870 | if (!e2) | |
1871 | return false; | |
1872 | } | |
1873 | ||
0dd0e980 | 1874 | return true; |
402209ff JH |
1875 | } |
1876 | ||
38109dab GL |
1877 | /* Returns true if BB basic block has a preserve label. */ |
1878 | ||
1879 | static bool | |
1880 | block_has_preserve_label (basic_block bb) | |
1881 | { | |
1882 | return (bb | |
1883 | && block_label (bb) | |
1884 | && LABEL_PRESERVE_P (block_label (bb))); | |
1885 | } | |
1886 | ||
402209ff JH |
1887 | /* E1 and E2 are edges with the same destination block. Search their |
1888 | predecessors for common code. If found, redirect control flow from | |
bf22920b TV |
1889 | (maybe the middle of) E1->SRC to (maybe the middle of) E2->SRC (dir_forward), |
1890 | or the other way around (dir_backward). DIR specifies the allowed | |
1891 | replacement direction. */ | |
402209ff JH |
1892 | |
1893 | static bool | |
bf22920b TV |
1894 | try_crossjump_to_edge (int mode, edge e1, edge e2, |
1895 | enum replace_direction dir) | |
402209ff | 1896 | { |
c2fc5456 | 1897 | int nmatch; |
402209ff | 1898 | basic_block src1 = e1->src, src2 = e2->src; |
39587bb9 | 1899 | basic_block redirect_to, redirect_from, to_remove; |
823918ae | 1900 | basic_block osrc1, osrc2, redirect_edges_to, tmp; |
da5477a9 | 1901 | rtx_insn *newpos1, *newpos2; |
402209ff | 1902 | edge s; |
628f6a4e | 1903 | edge_iterator ei; |
c2fc5456 | 1904 | |
da5477a9 | 1905 | newpos1 = newpos2 = NULL; |
6de9cd9a | 1906 | |
750054a2 | 1907 | /* If we have partitioned hot/cold basic blocks, it is a bad idea |
c22cacf3 | 1908 | to try this optimization. |
8e8d5162 CT |
1909 | |
1910 | Basic block partitioning may result in some jumps that appear to | |
c22cacf3 MS |
1911 | be optimizable (or blocks that appear to be mergeable), but which really |
1912 | must be left untouched (they are required to make it safely across | |
1913 | partition boundaries). See the comments at the top of | |
8e8d5162 | 1914 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
750054a2 | 1915 | |
af205f67 | 1916 | if (crtl->has_bb_partition && reload_completed) |
750054a2 CT |
1917 | return false; |
1918 | ||
402209ff JH |
1919 | /* Search backward through forwarder blocks. We don't need to worry |
1920 | about multiple entry or chained forwarders, as they will be optimized | |
1921 | away. We do this to look past the unconditional jump following a | |
1922 | conditional jump that is required due to the current CFG shape. */ | |
c5cbcccf | 1923 | if (single_pred_p (src1) |
635559ab | 1924 | && FORWARDER_BLOCK_P (src1)) |
c5cbcccf | 1925 | e1 = single_pred_edge (src1), src1 = e1->src; |
5f0d2358 | 1926 | |
c5cbcccf | 1927 | if (single_pred_p (src2) |
635559ab | 1928 | && FORWARDER_BLOCK_P (src2)) |
c5cbcccf | 1929 | e2 = single_pred_edge (src2), src2 = e2->src; |
402209ff JH |
1930 | |
1931 | /* Nothing to do if we reach ENTRY, or a common source block. */ | |
fefa31b5 DM |
1932 | if (src1 == ENTRY_BLOCK_PTR_FOR_FN (cfun) || src2 |
1933 | == ENTRY_BLOCK_PTR_FOR_FN (cfun)) | |
402209ff JH |
1934 | return false; |
1935 | if (src1 == src2) | |
1936 | return false; | |
1937 | ||
1938 | /* Seeing more than 1 forwarder blocks would confuse us later... */ | |
635559ab | 1939 | if (FORWARDER_BLOCK_P (e1->dest) |
c5cbcccf | 1940 | && FORWARDER_BLOCK_P (single_succ (e1->dest))) |
402209ff | 1941 | return false; |
5f0d2358 | 1942 | |
635559ab | 1943 | if (FORWARDER_BLOCK_P (e2->dest) |
c5cbcccf | 1944 | && FORWARDER_BLOCK_P (single_succ (e2->dest))) |
402209ff JH |
1945 | return false; |
1946 | ||
1947 | /* Likewise with dead code (possibly newly created by the other optimizations | |
1948 | of cfg_cleanup). */ | |
628f6a4e | 1949 | if (EDGE_COUNT (src1->preds) == 0 || EDGE_COUNT (src2->preds) == 0) |
402209ff JH |
1950 | return false; |
1951 | ||
402209ff | 1952 | /* Look for the common insn sequence, part the first ... */ |
c2fc5456 | 1953 | if (!outgoing_edges_match (mode, src1, src2)) |
402209ff JH |
1954 | return false; |
1955 | ||
1956 | /* ... and part the second. */ | |
472c95f5 | 1957 | nmatch = flow_find_cross_jump (src1, src2, &newpos1, &newpos2, &dir); |
12183e0f | 1958 | |
823918ae TV |
1959 | osrc1 = src1; |
1960 | osrc2 = src2; | |
1961 | if (newpos1 != NULL_RTX) | |
1962 | src1 = BLOCK_FOR_INSN (newpos1); | |
1963 | if (newpos2 != NULL_RTX) | |
1964 | src2 = BLOCK_FOR_INSN (newpos2); | |
1965 | ||
bf22920b TV |
1966 | if (dir == dir_backward) |
1967 | { | |
1968 | #define SWAP(T, X, Y) do { T tmp = (X); (X) = (Y); (Y) = tmp; } while (0) | |
1969 | SWAP (basic_block, osrc1, osrc2); | |
1970 | SWAP (basic_block, src1, src2); | |
1971 | SWAP (edge, e1, e2); | |
da5477a9 | 1972 | SWAP (rtx_insn *, newpos1, newpos2); |
bf22920b TV |
1973 | #undef SWAP |
1974 | } | |
1975 | ||
12183e0f PH |
1976 | /* Don't proceed with the crossjump unless we found a sufficient number |
1977 | of matching instructions or the 'from' block was totally matched | |
1978 | (such that its predecessors will hopefully be redirected and the | |
1979 | block removed). */ | |
c2fc5456 R |
1980 | if ((nmatch < PARAM_VALUE (PARAM_MIN_CROSSJUMP_INSNS)) |
1981 | && (newpos1 != BB_HEAD (src1))) | |
7d22e898 | 1982 | return false; |
402209ff | 1983 | |
75c40d56 | 1984 | /* Avoid deleting preserve label when redirecting ABNORMAL edges. */ |
38109dab GL |
1985 | if (block_has_preserve_label (e1->dest) |
1986 | && (e1->flags & EDGE_ABNORMAL)) | |
1987 | return false; | |
1988 | ||
39811184 JZ |
1989 | /* Here we know that the insns in the end of SRC1 which are common with SRC2 |
1990 | will be deleted. | |
1991 | If we have tablejumps in the end of SRC1 and SRC2 | |
1992 | they have been already compared for equivalence in outgoing_edges_match () | |
1993 | so replace the references to TABLE1 by references to TABLE2. */ | |
21c0a521 | 1994 | { |
39811184 | 1995 | rtx label1, label2; |
8942ee0f | 1996 | rtx_jump_table_data *table1, *table2; |
39811184 | 1997 | |
823918ae TV |
1998 | if (tablejump_p (BB_END (osrc1), &label1, &table1) |
1999 | && tablejump_p (BB_END (osrc2), &label2, &table2) | |
39811184 JZ |
2000 | && label1 != label2) |
2001 | { | |
da5477a9 | 2002 | rtx_insn *insn; |
39811184 JZ |
2003 | |
2004 | /* Replace references to LABEL1 with LABEL2. */ | |
39811184 JZ |
2005 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) |
2006 | { | |
2007 | /* Do not replace the label in SRC1->END because when deleting | |
2008 | a block whose end is a tablejump, the tablejump referenced | |
2009 | from the instruction is deleted too. */ | |
823918ae | 2010 | if (insn != BB_END (osrc1)) |
a2b7026c | 2011 | replace_label_in_insn (insn, label1, label2, true); |
39811184 JZ |
2012 | } |
2013 | } | |
21c0a521 | 2014 | } |
10d6c0d0 | 2015 | |
b604fe9b SB |
2016 | /* Avoid splitting if possible. We must always split when SRC2 has |
2017 | EH predecessor edges, or we may end up with basic blocks with both | |
2018 | normal and EH predecessor edges. */ | |
c2fc5456 | 2019 | if (newpos2 == BB_HEAD (src2) |
b604fe9b | 2020 | && !(EDGE_PRED (src2, 0)->flags & EDGE_EH)) |
402209ff JH |
2021 | redirect_to = src2; |
2022 | else | |
2023 | { | |
c2fc5456 | 2024 | if (newpos2 == BB_HEAD (src2)) |
b604fe9b SB |
2025 | { |
2026 | /* Skip possible basic block header. */ | |
c2fc5456 R |
2027 | if (LABEL_P (newpos2)) |
2028 | newpos2 = NEXT_INSN (newpos2); | |
b5b8b0ac AO |
2029 | while (DEBUG_INSN_P (newpos2)) |
2030 | newpos2 = NEXT_INSN (newpos2); | |
c2fc5456 R |
2031 | if (NOTE_P (newpos2)) |
2032 | newpos2 = NEXT_INSN (newpos2); | |
b5b8b0ac AO |
2033 | while (DEBUG_INSN_P (newpos2)) |
2034 | newpos2 = NEXT_INSN (newpos2); | |
b604fe9b SB |
2035 | } |
2036 | ||
c263766c RH |
2037 | if (dump_file) |
2038 | fprintf (dump_file, "Splitting bb %i before %i insns\n", | |
0b17ab2f | 2039 | src2->index, nmatch); |
c2fc5456 | 2040 | redirect_to = split_block (src2, PREV_INSN (newpos2))->dest; |
402209ff JH |
2041 | } |
2042 | ||
c263766c | 2043 | if (dump_file) |
c2fc5456 R |
2044 | fprintf (dump_file, |
2045 | "Cross jumping from bb %i to bb %i; %i common insns\n", | |
2046 | src1->index, src2->index, nmatch); | |
402209ff | 2047 | |
6fc0bb99 | 2048 | /* We may have some registers visible through the block. */ |
6fb5fa3c | 2049 | df_set_bb_dirty (redirect_to); |
402209ff | 2050 | |
823918ae TV |
2051 | if (osrc2 == src2) |
2052 | redirect_edges_to = redirect_to; | |
2053 | else | |
2054 | redirect_edges_to = osrc2; | |
2055 | ||
402209ff | 2056 | /* Recompute the frequencies and counts of outgoing edges. */ |
823918ae | 2057 | FOR_EACH_EDGE (s, ei, redirect_edges_to->succs) |
402209ff JH |
2058 | { |
2059 | edge s2; | |
628f6a4e | 2060 | edge_iterator ei; |
402209ff JH |
2061 | basic_block d = s->dest; |
2062 | ||
635559ab | 2063 | if (FORWARDER_BLOCK_P (d)) |
c5cbcccf | 2064 | d = single_succ (d); |
5f0d2358 | 2065 | |
628f6a4e | 2066 | FOR_EACH_EDGE (s2, ei, src1->succs) |
402209ff JH |
2067 | { |
2068 | basic_block d2 = s2->dest; | |
635559ab | 2069 | if (FORWARDER_BLOCK_P (d2)) |
c5cbcccf | 2070 | d2 = single_succ (d2); |
402209ff JH |
2071 | if (d == d2) |
2072 | break; | |
2073 | } | |
5f0d2358 | 2074 | |
402209ff JH |
2075 | s->count += s2->count; |
2076 | ||
2077 | /* Take care to update possible forwarder blocks. We verified | |
c22cacf3 MS |
2078 | that there is no more than one in the chain, so we can't run |
2079 | into infinite loop. */ | |
635559ab | 2080 | if (FORWARDER_BLOCK_P (s->dest)) |
402209ff | 2081 | { |
c5cbcccf | 2082 | single_succ_edge (s->dest)->count += s2->count; |
402209ff JH |
2083 | s->dest->count += s2->count; |
2084 | s->dest->frequency += EDGE_FREQUENCY (s); | |
2085 | } | |
5f0d2358 | 2086 | |
635559ab | 2087 | if (FORWARDER_BLOCK_P (s2->dest)) |
402209ff | 2088 | { |
c5cbcccf ZD |
2089 | single_succ_edge (s2->dest)->count -= s2->count; |
2090 | if (single_succ_edge (s2->dest)->count < 0) | |
2091 | single_succ_edge (s2->dest)->count = 0; | |
402209ff JH |
2092 | s2->dest->count -= s2->count; |
2093 | s2->dest->frequency -= EDGE_FREQUENCY (s); | |
b446e5a2 JH |
2094 | if (s2->dest->frequency < 0) |
2095 | s2->dest->frequency = 0; | |
2096 | if (s2->dest->count < 0) | |
2097 | s2->dest->count = 0; | |
402209ff | 2098 | } |
5f0d2358 | 2099 | |
823918ae | 2100 | if (!redirect_edges_to->frequency && !src1->frequency) |
402209ff JH |
2101 | s->probability = (s->probability + s2->probability) / 2; |
2102 | else | |
5f0d2358 | 2103 | s->probability |
823918ae | 2104 | = ((s->probability * redirect_edges_to->frequency + |
5f0d2358 | 2105 | s2->probability * src1->frequency) |
823918ae | 2106 | / (redirect_edges_to->frequency + src1->frequency)); |
402209ff JH |
2107 | } |
2108 | ||
52982a97 EB |
2109 | /* Adjust count and frequency for the block. An earlier jump |
2110 | threading pass may have left the profile in an inconsistent | |
2111 | state (see update_bb_profile_for_threading) so we must be | |
2112 | prepared for overflows. */ | |
823918ae TV |
2113 | tmp = redirect_to; |
2114 | do | |
2115 | { | |
2116 | tmp->count += src1->count; | |
2117 | tmp->frequency += src1->frequency; | |
2118 | if (tmp->frequency > BB_FREQ_MAX) | |
2119 | tmp->frequency = BB_FREQ_MAX; | |
2120 | if (tmp == redirect_edges_to) | |
2121 | break; | |
2122 | tmp = find_fallthru_edge (tmp->succs)->dest; | |
2123 | } | |
2124 | while (true); | |
2125 | update_br_prob_note (redirect_edges_to); | |
402209ff JH |
2126 | |
2127 | /* Edit SRC1 to go to REDIRECT_TO at NEWPOS1. */ | |
2128 | ||
c2fc5456 R |
2129 | /* Skip possible basic block header. */ |
2130 | if (LABEL_P (newpos1)) | |
2131 | newpos1 = NEXT_INSN (newpos1); | |
b5b8b0ac AO |
2132 | |
2133 | while (DEBUG_INSN_P (newpos1)) | |
2134 | newpos1 = NEXT_INSN (newpos1); | |
2135 | ||
cd9c1ca8 | 2136 | if (NOTE_INSN_BASIC_BLOCK_P (newpos1)) |
c2fc5456 R |
2137 | newpos1 = NEXT_INSN (newpos1); |
2138 | ||
b5b8b0ac AO |
2139 | while (DEBUG_INSN_P (newpos1)) |
2140 | newpos1 = NEXT_INSN (newpos1); | |
2141 | ||
c2fc5456 | 2142 | redirect_from = split_block (src1, PREV_INSN (newpos1))->src; |
c5cbcccf | 2143 | to_remove = single_succ (redirect_from); |
402209ff | 2144 | |
c5cbcccf | 2145 | redirect_edge_and_branch_force (single_succ_edge (redirect_from), redirect_to); |
f470c378 | 2146 | delete_basic_block (to_remove); |
402209ff | 2147 | |
39587bb9 | 2148 | update_forwarder_flag (redirect_from); |
7cbd12b8 JJ |
2149 | if (redirect_to != src2) |
2150 | update_forwarder_flag (src2); | |
635559ab | 2151 | |
402209ff JH |
2152 | return true; |
2153 | } | |
2154 | ||
2155 | /* Search the predecessors of BB for common insn sequences. When found, | |
2156 | share code between them by redirecting control flow. Return true if | |
2157 | any changes made. */ | |
2158 | ||
2159 | static bool | |
d329e058 | 2160 | try_crossjump_bb (int mode, basic_block bb) |
402209ff | 2161 | { |
628f6a4e | 2162 | edge e, e2, fallthru; |
402209ff | 2163 | bool changed; |
628f6a4e | 2164 | unsigned max, ix, ix2; |
402209ff | 2165 | |
f63d1bf7 | 2166 | /* Nothing to do if there is not at least two incoming edges. */ |
628f6a4e | 2167 | if (EDGE_COUNT (bb->preds) < 2) |
402209ff JH |
2168 | return false; |
2169 | ||
bbcb0c05 SB |
2170 | /* Don't crossjump if this block ends in a computed jump, |
2171 | unless we are optimizing for size. */ | |
efd8f750 | 2172 | if (optimize_bb_for_size_p (bb) |
fefa31b5 | 2173 | && bb != EXIT_BLOCK_PTR_FOR_FN (cfun) |
bbcb0c05 SB |
2174 | && computed_jump_p (BB_END (bb))) |
2175 | return false; | |
2176 | ||
750054a2 CT |
2177 | /* If we are partitioning hot/cold basic blocks, we don't want to |
2178 | mess up unconditional or indirect jumps that cross between hot | |
c22cacf3 MS |
2179 | and cold sections. |
2180 | ||
8e8d5162 | 2181 | Basic block partitioning may result in some jumps that appear to |
c22cacf3 MS |
2182 | be optimizable (or blocks that appear to be mergeable), but which really |
2183 | must be left untouched (they are required to make it safely across | |
2184 | partition boundaries). See the comments at the top of | |
8e8d5162 CT |
2185 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
2186 | ||
c22cacf3 MS |
2187 | if (BB_PARTITION (EDGE_PRED (bb, 0)->src) != |
2188 | BB_PARTITION (EDGE_PRED (bb, 1)->src) | |
87c8b4be | 2189 | || (EDGE_PRED (bb, 0)->flags & EDGE_CROSSING)) |
750054a2 CT |
2190 | return false; |
2191 | ||
402209ff JH |
2192 | /* It is always cheapest to redirect a block that ends in a branch to |
2193 | a block that falls through into BB, as that adds no branches to the | |
2194 | program. We'll try that combination first. */ | |
5f24e0dc RH |
2195 | fallthru = NULL; |
2196 | max = PARAM_VALUE (PARAM_MAX_CROSSJUMP_EDGES); | |
628f6a4e BE |
2197 | |
2198 | if (EDGE_COUNT (bb->preds) > max) | |
2199 | return false; | |
2200 | ||
0fd4b31d | 2201 | fallthru = find_fallthru_edge (bb->preds); |
402209ff JH |
2202 | |
2203 | changed = false; | |
0248bceb | 2204 | for (ix = 0; ix < EDGE_COUNT (bb->preds);) |
402209ff | 2205 | { |
0248bceb | 2206 | e = EDGE_PRED (bb, ix); |
628f6a4e | 2207 | ix++; |
402209ff | 2208 | |
c1e3e2d9 SB |
2209 | /* As noted above, first try with the fallthru predecessor (or, a |
2210 | fallthru predecessor if we are in cfglayout mode). */ | |
402209ff JH |
2211 | if (fallthru) |
2212 | { | |
2213 | /* Don't combine the fallthru edge into anything else. | |
2214 | If there is a match, we'll do it the other way around. */ | |
2215 | if (e == fallthru) | |
2216 | continue; | |
7cf240d5 JH |
2217 | /* If nothing changed since the last attempt, there is nothing |
2218 | we can do. */ | |
2219 | if (!first_pass | |
4ec5d4f5 BS |
2220 | && !((e->src->flags & BB_MODIFIED) |
2221 | || (fallthru->src->flags & BB_MODIFIED))) | |
7cf240d5 | 2222 | continue; |
402209ff | 2223 | |
bf22920b | 2224 | if (try_crossjump_to_edge (mode, e, fallthru, dir_forward)) |
402209ff JH |
2225 | { |
2226 | changed = true; | |
628f6a4e | 2227 | ix = 0; |
402209ff JH |
2228 | continue; |
2229 | } | |
2230 | } | |
2231 | ||
2232 | /* Non-obvious work limiting check: Recognize that we're going | |
2233 | to call try_crossjump_bb on every basic block. So if we have | |
2234 | two blocks with lots of outgoing edges (a switch) and they | |
2235 | share lots of common destinations, then we would do the | |
2236 | cross-jump check once for each common destination. | |
2237 | ||
2238 | Now, if the blocks actually are cross-jump candidates, then | |
2239 | all of their destinations will be shared. Which means that | |
2240 | we only need check them for cross-jump candidacy once. We | |
2241 | can eliminate redundant checks of crossjump(A,B) by arbitrarily | |
2242 | choosing to do the check from the block for which the edge | |
2243 | in question is the first successor of A. */ | |
628f6a4e | 2244 | if (EDGE_SUCC (e->src, 0) != e) |
402209ff JH |
2245 | continue; |
2246 | ||
0248bceb | 2247 | for (ix2 = 0; ix2 < EDGE_COUNT (bb->preds); ix2++) |
402209ff | 2248 | { |
0248bceb | 2249 | e2 = EDGE_PRED (bb, ix2); |
402209ff JH |
2250 | |
2251 | if (e2 == e) | |
2252 | continue; | |
2253 | ||
2254 | /* We've already checked the fallthru edge above. */ | |
2255 | if (e2 == fallthru) | |
2256 | continue; | |
2257 | ||
402209ff JH |
2258 | /* The "first successor" check above only prevents multiple |
2259 | checks of crossjump(A,B). In order to prevent redundant | |
2260 | checks of crossjump(B,A), require that A be the block | |
2261 | with the lowest index. */ | |
0b17ab2f | 2262 | if (e->src->index > e2->src->index) |
402209ff JH |
2263 | continue; |
2264 | ||
7cf240d5 JH |
2265 | /* If nothing changed since the last attempt, there is nothing |
2266 | we can do. */ | |
2267 | if (!first_pass | |
4ec5d4f5 BS |
2268 | && !((e->src->flags & BB_MODIFIED) |
2269 | || (e2->src->flags & BB_MODIFIED))) | |
7cf240d5 JH |
2270 | continue; |
2271 | ||
bf22920b TV |
2272 | /* Both e and e2 are not fallthru edges, so we can crossjump in either |
2273 | direction. */ | |
2274 | if (try_crossjump_to_edge (mode, e, e2, dir_both)) | |
402209ff JH |
2275 | { |
2276 | changed = true; | |
628f6a4e | 2277 | ix = 0; |
402209ff JH |
2278 | break; |
2279 | } | |
2280 | } | |
2281 | } | |
2282 | ||
c1e3e2d9 SB |
2283 | if (changed) |
2284 | crossjumps_occured = true; | |
2285 | ||
402209ff JH |
2286 | return changed; |
2287 | } | |
2288 | ||
4ec5d4f5 BS |
2289 | /* Search the successors of BB for common insn sequences. When found, |
2290 | share code between them by moving it across the basic block | |
2291 | boundary. Return true if any changes made. */ | |
2292 | ||
2293 | static bool | |
2294 | try_head_merge_bb (basic_block bb) | |
2295 | { | |
2296 | basic_block final_dest_bb = NULL; | |
2297 | int max_match = INT_MAX; | |
2298 | edge e0; | |
da5477a9 | 2299 | rtx_insn **headptr, **currptr, **nextptr; |
4ec5d4f5 BS |
2300 | bool changed, moveall; |
2301 | unsigned ix; | |
da5477a9 | 2302 | rtx_insn *e0_last_head; |
61aa0978 DM |
2303 | rtx cond; |
2304 | rtx_insn *move_before; | |
4ec5d4f5 | 2305 | unsigned nedges = EDGE_COUNT (bb->succs); |
da5477a9 | 2306 | rtx_insn *jump = BB_END (bb); |
4ec5d4f5 BS |
2307 | regset live, live_union; |
2308 | ||
2309 | /* Nothing to do if there is not at least two outgoing edges. */ | |
2310 | if (nedges < 2) | |
2311 | return false; | |
2312 | ||
2313 | /* Don't crossjump if this block ends in a computed jump, | |
2314 | unless we are optimizing for size. */ | |
2315 | if (optimize_bb_for_size_p (bb) | |
fefa31b5 | 2316 | && bb != EXIT_BLOCK_PTR_FOR_FN (cfun) |
4ec5d4f5 BS |
2317 | && computed_jump_p (BB_END (bb))) |
2318 | return false; | |
2319 | ||
2320 | cond = get_condition (jump, &move_before, true, false); | |
2321 | if (cond == NULL_RTX) | |
43052d45 | 2322 | { |
618f4073 | 2323 | if (HAVE_cc0 && reg_mentioned_p (cc0_rtx, jump)) |
43052d45 BS |
2324 | move_before = prev_nonnote_nondebug_insn (jump); |
2325 | else | |
43052d45 BS |
2326 | move_before = jump; |
2327 | } | |
4ec5d4f5 BS |
2328 | |
2329 | for (ix = 0; ix < nedges; ix++) | |
fefa31b5 | 2330 | if (EDGE_SUCC (bb, ix)->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
4ec5d4f5 BS |
2331 | return false; |
2332 | ||
2333 | for (ix = 0; ix < nedges; ix++) | |
2334 | { | |
2335 | edge e = EDGE_SUCC (bb, ix); | |
2336 | basic_block other_bb = e->dest; | |
2337 | ||
2338 | if (df_get_bb_dirty (other_bb)) | |
2339 | { | |
2340 | block_was_dirty = true; | |
2341 | return false; | |
2342 | } | |
2343 | ||
2344 | if (e->flags & EDGE_ABNORMAL) | |
2345 | return false; | |
2346 | ||
2347 | /* Normally, all destination blocks must only be reachable from this | |
2348 | block, i.e. they must have one incoming edge. | |
2349 | ||
2350 | There is one special case we can handle, that of multiple consecutive | |
2351 | jumps where the first jumps to one of the targets of the second jump. | |
2352 | This happens frequently in switch statements for default labels. | |
2353 | The structure is as follows: | |
2354 | FINAL_DEST_BB | |
2355 | .... | |
2356 | if (cond) jump A; | |
2357 | fall through | |
2358 | BB | |
2359 | jump with targets A, B, C, D... | |
2360 | A | |
2361 | has two incoming edges, from FINAL_DEST_BB and BB | |
2362 | ||
2363 | In this case, we can try to move the insns through BB and into | |
2364 | FINAL_DEST_BB. */ | |
2365 | if (EDGE_COUNT (other_bb->preds) != 1) | |
2366 | { | |
2367 | edge incoming_edge, incoming_bb_other_edge; | |
2368 | edge_iterator ei; | |
2369 | ||
2370 | if (final_dest_bb != NULL | |
2371 | || EDGE_COUNT (other_bb->preds) != 2) | |
2372 | return false; | |
2373 | ||
2374 | /* We must be able to move the insns across the whole block. */ | |
2375 | move_before = BB_HEAD (bb); | |
2376 | while (!NONDEBUG_INSN_P (move_before)) | |
2377 | move_before = NEXT_INSN (move_before); | |
2378 | ||
2379 | if (EDGE_COUNT (bb->preds) != 1) | |
2380 | return false; | |
2381 | incoming_edge = EDGE_PRED (bb, 0); | |
2382 | final_dest_bb = incoming_edge->src; | |
2383 | if (EDGE_COUNT (final_dest_bb->succs) != 2) | |
2384 | return false; | |
2385 | FOR_EACH_EDGE (incoming_bb_other_edge, ei, final_dest_bb->succs) | |
2386 | if (incoming_bb_other_edge != incoming_edge) | |
2387 | break; | |
2388 | if (incoming_bb_other_edge->dest != other_bb) | |
2389 | return false; | |
2390 | } | |
2391 | } | |
2392 | ||
2393 | e0 = EDGE_SUCC (bb, 0); | |
da5477a9 | 2394 | e0_last_head = NULL; |
4ec5d4f5 BS |
2395 | changed = false; |
2396 | ||
2397 | for (ix = 1; ix < nedges; ix++) | |
2398 | { | |
2399 | edge e = EDGE_SUCC (bb, ix); | |
da5477a9 | 2400 | rtx_insn *e0_last, *e_last; |
4ec5d4f5 BS |
2401 | int nmatch; |
2402 | ||
2403 | nmatch = flow_find_head_matching_sequence (e0->dest, e->dest, | |
2404 | &e0_last, &e_last, 0); | |
2405 | if (nmatch == 0) | |
2406 | return false; | |
2407 | ||
2408 | if (nmatch < max_match) | |
2409 | { | |
2410 | max_match = nmatch; | |
2411 | e0_last_head = e0_last; | |
2412 | } | |
2413 | } | |
2414 | ||
2415 | /* If we matched an entire block, we probably have to avoid moving the | |
2416 | last insn. */ | |
2417 | if (max_match > 0 | |
2418 | && e0_last_head == BB_END (e0->dest) | |
2419 | && (find_reg_note (e0_last_head, REG_EH_REGION, 0) | |
2420 | || control_flow_insn_p (e0_last_head))) | |
2421 | { | |
2422 | max_match--; | |
2423 | if (max_match == 0) | |
2424 | return false; | |
b59e0455 JJ |
2425 | do |
2426 | e0_last_head = prev_real_insn (e0_last_head); | |
2427 | while (DEBUG_INSN_P (e0_last_head)); | |
4ec5d4f5 BS |
2428 | } |
2429 | ||
2430 | if (max_match == 0) | |
2431 | return false; | |
2432 | ||
2433 | /* We must find a union of the live registers at each of the end points. */ | |
2434 | live = BITMAP_ALLOC (NULL); | |
2435 | live_union = BITMAP_ALLOC (NULL); | |
2436 | ||
da5477a9 DM |
2437 | currptr = XNEWVEC (rtx_insn *, nedges); |
2438 | headptr = XNEWVEC (rtx_insn *, nedges); | |
2439 | nextptr = XNEWVEC (rtx_insn *, nedges); | |
4ec5d4f5 BS |
2440 | |
2441 | for (ix = 0; ix < nedges; ix++) | |
2442 | { | |
2443 | int j; | |
2444 | basic_block merge_bb = EDGE_SUCC (bb, ix)->dest; | |
da5477a9 | 2445 | rtx_insn *head = BB_HEAD (merge_bb); |
4ec5d4f5 | 2446 | |
b59e0455 JJ |
2447 | while (!NONDEBUG_INSN_P (head)) |
2448 | head = NEXT_INSN (head); | |
4ec5d4f5 BS |
2449 | headptr[ix] = head; |
2450 | currptr[ix] = head; | |
2451 | ||
2452 | /* Compute the end point and live information */ | |
2453 | for (j = 1; j < max_match; j++) | |
b59e0455 JJ |
2454 | do |
2455 | head = NEXT_INSN (head); | |
2456 | while (!NONDEBUG_INSN_P (head)); | |
4ec5d4f5 BS |
2457 | simulate_backwards_to_point (merge_bb, live, head); |
2458 | IOR_REG_SET (live_union, live); | |
2459 | } | |
2460 | ||
2461 | /* If we're moving across two blocks, verify the validity of the | |
2462 | first move, then adjust the target and let the loop below deal | |
2463 | with the final move. */ | |
2464 | if (final_dest_bb != NULL) | |
2465 | { | |
61aa0978 | 2466 | rtx_insn *move_upto; |
4ec5d4f5 BS |
2467 | |
2468 | moveall = can_move_insns_across (currptr[0], e0_last_head, move_before, | |
2469 | jump, e0->dest, live_union, | |
2470 | NULL, &move_upto); | |
2471 | if (!moveall) | |
2472 | { | |
2473 | if (move_upto == NULL_RTX) | |
2474 | goto out; | |
2475 | ||
2476 | while (e0_last_head != move_upto) | |
2477 | { | |
2478 | df_simulate_one_insn_backwards (e0->dest, e0_last_head, | |
2479 | live_union); | |
2480 | e0_last_head = PREV_INSN (e0_last_head); | |
2481 | } | |
2482 | } | |
2483 | if (e0_last_head == NULL_RTX) | |
2484 | goto out; | |
2485 | ||
2486 | jump = BB_END (final_dest_bb); | |
2487 | cond = get_condition (jump, &move_before, true, false); | |
2488 | if (cond == NULL_RTX) | |
43052d45 | 2489 | { |
618f4073 | 2490 | if (HAVE_cc0 && reg_mentioned_p (cc0_rtx, jump)) |
43052d45 BS |
2491 | move_before = prev_nonnote_nondebug_insn (jump); |
2492 | else | |
43052d45 BS |
2493 | move_before = jump; |
2494 | } | |
4ec5d4f5 BS |
2495 | } |
2496 | ||
2497 | do | |
2498 | { | |
61aa0978 | 2499 | rtx_insn *move_upto; |
4ec5d4f5 BS |
2500 | moveall = can_move_insns_across (currptr[0], e0_last_head, |
2501 | move_before, jump, e0->dest, live_union, | |
2502 | NULL, &move_upto); | |
2503 | if (!moveall && move_upto == NULL_RTX) | |
2504 | { | |
2505 | if (jump == move_before) | |
2506 | break; | |
2507 | ||
2508 | /* Try again, using a different insertion point. */ | |
2509 | move_before = jump; | |
2510 | ||
4ec5d4f5 BS |
2511 | /* Don't try moving before a cc0 user, as that may invalidate |
2512 | the cc0. */ | |
618f4073 | 2513 | if (HAVE_cc0 && reg_mentioned_p (cc0_rtx, jump)) |
4ec5d4f5 | 2514 | break; |
4ec5d4f5 BS |
2515 | |
2516 | continue; | |
2517 | } | |
2518 | ||
2519 | if (final_dest_bb && !moveall) | |
2520 | /* We haven't checked whether a partial move would be OK for the first | |
2521 | move, so we have to fail this case. */ | |
2522 | break; | |
2523 | ||
2524 | changed = true; | |
2525 | for (;;) | |
2526 | { | |
2527 | if (currptr[0] == move_upto) | |
2528 | break; | |
2529 | for (ix = 0; ix < nedges; ix++) | |
2530 | { | |
da5477a9 | 2531 | rtx_insn *curr = currptr[ix]; |
4ec5d4f5 BS |
2532 | do |
2533 | curr = NEXT_INSN (curr); | |
2534 | while (!NONDEBUG_INSN_P (curr)); | |
2535 | currptr[ix] = curr; | |
2536 | } | |
2537 | } | |
2538 | ||
2539 | /* If we can't currently move all of the identical insns, remember | |
2540 | each insn after the range that we'll merge. */ | |
2541 | if (!moveall) | |
2542 | for (ix = 0; ix < nedges; ix++) | |
2543 | { | |
da5477a9 | 2544 | rtx_insn *curr = currptr[ix]; |
4ec5d4f5 BS |
2545 | do |
2546 | curr = NEXT_INSN (curr); | |
2547 | while (!NONDEBUG_INSN_P (curr)); | |
2548 | nextptr[ix] = curr; | |
2549 | } | |
2550 | ||
2551 | reorder_insns (headptr[0], currptr[0], PREV_INSN (move_before)); | |
2552 | df_set_bb_dirty (EDGE_SUCC (bb, 0)->dest); | |
2553 | if (final_dest_bb != NULL) | |
2554 | df_set_bb_dirty (final_dest_bb); | |
2555 | df_set_bb_dirty (bb); | |
2556 | for (ix = 1; ix < nedges; ix++) | |
2557 | { | |
2558 | df_set_bb_dirty (EDGE_SUCC (bb, ix)->dest); | |
2559 | delete_insn_chain (headptr[ix], currptr[ix], false); | |
2560 | } | |
2561 | if (!moveall) | |
2562 | { | |
2563 | if (jump == move_before) | |
2564 | break; | |
2565 | ||
2566 | /* For the unmerged insns, try a different insertion point. */ | |
2567 | move_before = jump; | |
2568 | ||
4ec5d4f5 BS |
2569 | /* Don't try moving before a cc0 user, as that may invalidate |
2570 | the cc0. */ | |
618f4073 | 2571 | if (HAVE_cc0 && reg_mentioned_p (cc0_rtx, jump)) |
4ec5d4f5 | 2572 | break; |
4ec5d4f5 BS |
2573 | |
2574 | for (ix = 0; ix < nedges; ix++) | |
2575 | currptr[ix] = headptr[ix] = nextptr[ix]; | |
2576 | } | |
2577 | } | |
2578 | while (!moveall); | |
2579 | ||
2580 | out: | |
2581 | free (currptr); | |
2582 | free (headptr); | |
2583 | free (nextptr); | |
2584 | ||
2585 | crossjumps_occured |= changed; | |
2586 | ||
2587 | return changed; | |
2588 | } | |
2589 | ||
7752e522 JJ |
2590 | /* Return true if BB contains just bb note, or bb note followed |
2591 | by only DEBUG_INSNs. */ | |
2592 | ||
2593 | static bool | |
2594 | trivially_empty_bb_p (basic_block bb) | |
2595 | { | |
da5477a9 | 2596 | rtx_insn *insn = BB_END (bb); |
7752e522 JJ |
2597 | |
2598 | while (1) | |
2599 | { | |
2600 | if (insn == BB_HEAD (bb)) | |
2601 | return true; | |
2602 | if (!DEBUG_INSN_P (insn)) | |
2603 | return false; | |
2604 | insn = PREV_INSN (insn); | |
2605 | } | |
2606 | } | |
2607 | ||
402209ff JH |
2608 | /* Do simple CFG optimizations - basic block merging, simplifying of jump |
2609 | instructions etc. Return nonzero if changes were made. */ | |
2610 | ||
2611 | static bool | |
d329e058 | 2612 | try_optimize_cfg (int mode) |
402209ff | 2613 | { |
402209ff JH |
2614 | bool changed_overall = false; |
2615 | bool changed; | |
2616 | int iterations = 0; | |
ec3ae3da | 2617 | basic_block bb, b, next; |
402209ff | 2618 | |
6fb5fa3c | 2619 | if (mode & (CLEANUP_CROSSJUMP | CLEANUP_THREADING)) |
38c1593d JH |
2620 | clear_bb_flags (); |
2621 | ||
c1e3e2d9 SB |
2622 | crossjumps_occured = false; |
2623 | ||
11cd3bed | 2624 | FOR_EACH_BB_FN (bb, cfun) |
2dd2d53e SB |
2625 | update_forwarder_flag (bb); |
2626 | ||
245f1bfa | 2627 | if (! targetm.cannot_modify_jumps_p ()) |
402209ff | 2628 | { |
7cf240d5 | 2629 | first_pass = true; |
e4ec2cac AO |
2630 | /* Attempt to merge blocks as made possible by edge removal. If |
2631 | a block has only one successor, and the successor has only | |
2632 | one predecessor, they may be combined. */ | |
2633 | do | |
402209ff | 2634 | { |
4ec5d4f5 | 2635 | block_was_dirty = false; |
e4ec2cac AO |
2636 | changed = false; |
2637 | iterations++; | |
2638 | ||
c263766c RH |
2639 | if (dump_file) |
2640 | fprintf (dump_file, | |
e4ec2cac AO |
2641 | "\n\ntry_optimize_cfg iteration %i\n\n", |
2642 | iterations); | |
402209ff | 2643 | |
fefa31b5 DM |
2644 | for (b = ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb; b |
2645 | != EXIT_BLOCK_PTR_FOR_FN (cfun);) | |
402209ff | 2646 | { |
e0082a72 | 2647 | basic_block c; |
e4ec2cac AO |
2648 | edge s; |
2649 | bool changed_here = false; | |
5f0d2358 | 2650 | |
468059bc DD |
2651 | /* Delete trivially dead basic blocks. This is either |
2652 | blocks with no predecessors, or empty blocks with no | |
1e211590 DD |
2653 | successors. However if the empty block with no |
2654 | successors is the successor of the ENTRY_BLOCK, it is | |
2655 | kept. This ensures that the ENTRY_BLOCK will have a | |
2656 | successor which is a precondition for many RTL | |
2657 | passes. Empty blocks may result from expanding | |
468059bc DD |
2658 | __builtin_unreachable (). */ |
2659 | if (EDGE_COUNT (b->preds) == 0 | |
1e211590 | 2660 | || (EDGE_COUNT (b->succs) == 0 |
7752e522 | 2661 | && trivially_empty_bb_p (b) |
fefa31b5 DM |
2662 | && single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun))->dest |
2663 | != b)) | |
e4ec2cac | 2664 | { |
f6366fc7 | 2665 | c = b->prev_bb; |
f1de5107 | 2666 | if (EDGE_COUNT (b->preds) > 0) |
3b5fda81 JJ |
2667 | { |
2668 | edge e; | |
2669 | edge_iterator ei; | |
2670 | ||
f1de5107 JJ |
2671 | if (current_ir_type () == IR_RTL_CFGLAYOUT) |
2672 | { | |
bcc708fc MM |
2673 | if (BB_FOOTER (b) |
2674 | && BARRIER_P (BB_FOOTER (b))) | |
f1de5107 JJ |
2675 | FOR_EACH_EDGE (e, ei, b->preds) |
2676 | if ((e->flags & EDGE_FALLTHRU) | |
bcc708fc | 2677 | && BB_FOOTER (e->src) == NULL) |
f1de5107 | 2678 | { |
bcc708fc | 2679 | if (BB_FOOTER (b)) |
f1de5107 | 2680 | { |
d8ce2eae DM |
2681 | BB_FOOTER (e->src) = BB_FOOTER (b); |
2682 | BB_FOOTER (b) = NULL; | |
f1de5107 JJ |
2683 | } |
2684 | else | |
2685 | { | |
2686 | start_sequence (); | |
d8ce2eae | 2687 | BB_FOOTER (e->src) = emit_barrier (); |
f1de5107 JJ |
2688 | end_sequence (); |
2689 | } | |
2690 | } | |
2691 | } | |
2692 | else | |
2693 | { | |
da5477a9 | 2694 | rtx_insn *last = get_last_bb_insn (b); |
f1de5107 JJ |
2695 | if (last && BARRIER_P (last)) |
2696 | FOR_EACH_EDGE (e, ei, b->preds) | |
2697 | if ((e->flags & EDGE_FALLTHRU)) | |
2698 | emit_barrier_after (BB_END (e->src)); | |
2699 | } | |
3b5fda81 | 2700 | } |
f470c378 | 2701 | delete_basic_block (b); |
bef16e87 | 2702 | changed = true; |
6626665f | 2703 | /* Avoid trying to remove the exit block. */ |
fefa31b5 | 2704 | b = (c == ENTRY_BLOCK_PTR_FOR_FN (cfun) ? c->next_bb : c); |
83bd032b | 2705 | continue; |
e4ec2cac | 2706 | } |
402209ff | 2707 | |
6ce2bcb7 | 2708 | /* Remove code labels no longer used. */ |
c5cbcccf ZD |
2709 | if (single_pred_p (b) |
2710 | && (single_pred_edge (b)->flags & EDGE_FALLTHRU) | |
2711 | && !(single_pred_edge (b)->flags & EDGE_COMPLEX) | |
4b4bf941 | 2712 | && LABEL_P (BB_HEAD (b)) |
6c979aa1 | 2713 | && !LABEL_PRESERVE_P (BB_HEAD (b)) |
e4ec2cac AO |
2714 | /* If the previous block ends with a branch to this |
2715 | block, we can't delete the label. Normally this | |
2716 | is a condjump that is yet to be simplified, but | |
2717 | if CASE_DROPS_THRU, this can be a tablejump with | |
2718 | some element going to the same place as the | |
2719 | default (fallthru). */ | |
fefa31b5 | 2720 | && (single_pred (b) == ENTRY_BLOCK_PTR_FOR_FN (cfun) |
c5cbcccf | 2721 | || !JUMP_P (BB_END (single_pred (b))) |
a813c111 | 2722 | || ! label_is_jump_target_p (BB_HEAD (b), |
c5cbcccf | 2723 | BB_END (single_pred (b))))) |
e4ec2cac | 2724 | { |
03fbe718 | 2725 | delete_insn (BB_HEAD (b)); |
c263766c RH |
2726 | if (dump_file) |
2727 | fprintf (dump_file, "Deleted label in block %i.\n", | |
0b17ab2f | 2728 | b->index); |
e4ec2cac | 2729 | } |
402209ff | 2730 | |
e4ec2cac | 2731 | /* If we fall through an empty block, we can remove it. */ |
9be94227 | 2732 | if (!(mode & (CLEANUP_CFGLAYOUT | CLEANUP_NO_INSN_DEL)) |
c5cbcccf ZD |
2733 | && single_pred_p (b) |
2734 | && (single_pred_edge (b)->flags & EDGE_FALLTHRU) | |
4b4bf941 | 2735 | && !LABEL_P (BB_HEAD (b)) |
e4ec2cac AO |
2736 | && FORWARDER_BLOCK_P (b) |
2737 | /* Note that forwarder_block_p true ensures that | |
2738 | there is a successor for this block. */ | |
c5cbcccf | 2739 | && (single_succ_edge (b)->flags & EDGE_FALLTHRU) |
0cae8d31 | 2740 | && n_basic_blocks_for_fn (cfun) > NUM_FIXED_BLOCKS + 1) |
e4ec2cac | 2741 | { |
c263766c RH |
2742 | if (dump_file) |
2743 | fprintf (dump_file, | |
e4ec2cac | 2744 | "Deleting fallthru block %i.\n", |
0b17ab2f | 2745 | b->index); |
e4ec2cac | 2746 | |
fefa31b5 DM |
2747 | c = ((b->prev_bb == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
2748 | ? b->next_bb : b->prev_bb); | |
c5cbcccf ZD |
2749 | redirect_edge_succ_nodup (single_pred_edge (b), |
2750 | single_succ (b)); | |
f470c378 | 2751 | delete_basic_block (b); |
e4ec2cac AO |
2752 | changed = true; |
2753 | b = c; | |
1e211590 | 2754 | continue; |
e4ec2cac | 2755 | } |
5f0d2358 | 2756 | |
50a36e42 | 2757 | /* Merge B with its single successor, if any. */ |
c5cbcccf ZD |
2758 | if (single_succ_p (b) |
2759 | && (s = single_succ_edge (b)) | |
ec3ae3da | 2760 | && !(s->flags & EDGE_COMPLEX) |
fefa31b5 | 2761 | && (c = s->dest) != EXIT_BLOCK_PTR_FOR_FN (cfun) |
c5cbcccf | 2762 | && single_pred_p (c) |
bc35512f JH |
2763 | && b != c) |
2764 | { | |
2765 | /* When not in cfg_layout mode use code aware of reordering | |
2766 | INSN. This code possibly creates new basic blocks so it | |
2767 | does not fit merge_blocks interface and is kept here in | |
2768 | hope that it will become useless once more of compiler | |
2769 | is transformed to use cfg_layout mode. */ | |
c22cacf3 | 2770 | |
bc35512f JH |
2771 | if ((mode & CLEANUP_CFGLAYOUT) |
2772 | && can_merge_blocks_p (b, c)) | |
2773 | { | |
2774 | merge_blocks (b, c); | |
2775 | update_forwarder_flag (b); | |
2776 | changed_here = true; | |
2777 | } | |
2778 | else if (!(mode & CLEANUP_CFGLAYOUT) | |
2779 | /* If the jump insn has side effects, | |
2780 | we can't kill the edge. */ | |
4b4bf941 | 2781 | && (!JUMP_P (BB_END (b)) |
e24e7211 | 2782 | || (reload_completed |
a813c111 | 2783 | ? simplejump_p (BB_END (b)) |
e4efa971 JH |
2784 | : (onlyjump_p (BB_END (b)) |
2785 | && !tablejump_p (BB_END (b), | |
2786 | NULL, NULL)))) | |
bc35512f JH |
2787 | && (next = merge_blocks_move (s, b, c, mode))) |
2788 | { | |
2789 | b = next; | |
2790 | changed_here = true; | |
2791 | } | |
ec3ae3da | 2792 | } |
e4ec2cac AO |
2793 | |
2794 | /* Simplify branch over branch. */ | |
bc35512f JH |
2795 | if ((mode & CLEANUP_EXPENSIVE) |
2796 | && !(mode & CLEANUP_CFGLAYOUT) | |
2797 | && try_simplify_condjump (b)) | |
38c1593d | 2798 | changed_here = true; |
402209ff | 2799 | |
e4ec2cac AO |
2800 | /* If B has a single outgoing edge, but uses a |
2801 | non-trivial jump instruction without side-effects, we | |
2802 | can either delete the jump entirely, or replace it | |
3348b696 | 2803 | with a simple unconditional jump. */ |
c5cbcccf | 2804 | if (single_succ_p (b) |
fefa31b5 | 2805 | && single_succ (b) != EXIT_BLOCK_PTR_FOR_FN (cfun) |
a813c111 | 2806 | && onlyjump_p (BB_END (b)) |
339ba33b | 2807 | && !CROSSING_JUMP_P (BB_END (b)) |
c5cbcccf ZD |
2808 | && try_redirect_by_replacing_jump (single_succ_edge (b), |
2809 | single_succ (b), | |
20b4e8ae | 2810 | (mode & CLEANUP_CFGLAYOUT) != 0)) |
e4ec2cac | 2811 | { |
e4ec2cac AO |
2812 | update_forwarder_flag (b); |
2813 | changed_here = true; | |
2814 | } | |
402209ff | 2815 | |
e4ec2cac AO |
2816 | /* Simplify branch to branch. */ |
2817 | if (try_forward_edges (mode, b)) | |
afe8b6ec EB |
2818 | { |
2819 | update_forwarder_flag (b); | |
2820 | changed_here = true; | |
2821 | } | |
402209ff | 2822 | |
e4ec2cac AO |
2823 | /* Look for shared code between blocks. */ |
2824 | if ((mode & CLEANUP_CROSSJUMP) | |
2825 | && try_crossjump_bb (mode, b)) | |
2826 | changed_here = true; | |
402209ff | 2827 | |
4ec5d4f5 BS |
2828 | if ((mode & CLEANUP_CROSSJUMP) |
2829 | /* This can lengthen register lifetimes. Do it only after | |
2830 | reload. */ | |
2831 | && reload_completed | |
2832 | && try_head_merge_bb (b)) | |
2833 | changed_here = true; | |
2834 | ||
e4ec2cac AO |
2835 | /* Don't get confused by the index shift caused by |
2836 | deleting blocks. */ | |
2837 | if (!changed_here) | |
e0082a72 | 2838 | b = b->next_bb; |
e4ec2cac AO |
2839 | else |
2840 | changed = true; | |
2841 | } | |
402209ff | 2842 | |
e4ec2cac | 2843 | if ((mode & CLEANUP_CROSSJUMP) |
fefa31b5 | 2844 | && try_crossjump_bb (mode, EXIT_BLOCK_PTR_FOR_FN (cfun))) |
402209ff | 2845 | changed = true; |
402209ff | 2846 | |
4ec5d4f5 BS |
2847 | if (block_was_dirty) |
2848 | { | |
2849 | /* This should only be set by head-merging. */ | |
2850 | gcc_assert (mode & CLEANUP_CROSSJUMP); | |
2851 | df_analyze (); | |
2852 | } | |
2853 | ||
e4ec2cac | 2854 | if (changed) |
600b5b1d TJ |
2855 | { |
2856 | /* Edge forwarding in particular can cause hot blocks previously | |
2857 | reached by both hot and cold blocks to become dominated only | |
2858 | by cold blocks. This will cause the verification below to fail, | |
2859 | and lead to now cold code in the hot section. This is not easy | |
2860 | to detect and fix during edge forwarding, and in some cases | |
2861 | is only visible after newly unreachable blocks are deleted, | |
2862 | which will be done in fixup_partitions. */ | |
b2b29377 MM |
2863 | fixup_partitions (); |
2864 | checking_verify_flow_info (); | |
600b5b1d | 2865 | } |
402209ff | 2866 | |
e4ec2cac | 2867 | changed_overall |= changed; |
7cf240d5 | 2868 | first_pass = false; |
e4ec2cac AO |
2869 | } |
2870 | while (changed); | |
402209ff | 2871 | } |
ca6c03ca | 2872 | |
04a90bec | 2873 | FOR_ALL_BB_FN (b, cfun) |
2dd2d53e | 2874 | b->flags &= ~(BB_FORWARDER_BLOCK | BB_NONTHREADABLE_BLOCK); |
635559ab | 2875 | |
402209ff JH |
2876 | return changed_overall; |
2877 | } | |
2878 | \f | |
6d2f8887 | 2879 | /* Delete all unreachable basic blocks. */ |
4262e623 | 2880 | |
969d70ca | 2881 | bool |
d329e058 | 2882 | delete_unreachable_blocks (void) |
402209ff | 2883 | { |
402209ff | 2884 | bool changed = false; |
b5b8b0ac | 2885 | basic_block b, prev_bb; |
402209ff JH |
2886 | |
2887 | find_unreachable_blocks (); | |
2888 | ||
b5b8b0ac AO |
2889 | /* When we're in GIMPLE mode and there may be debug insns, we should |
2890 | delete blocks in reverse dominator order, so as to get a chance | |
2891 | to substitute all released DEFs into debug stmts. If we don't | |
2892 | have dominators information, walking blocks backward gets us a | |
2893 | better chance of retaining most debug information than | |
2894 | otherwise. */ | |
532aafad | 2895 | if (MAY_HAVE_DEBUG_INSNS && current_ir_type () == IR_GIMPLE |
b5b8b0ac | 2896 | && dom_info_available_p (CDI_DOMINATORS)) |
402209ff | 2897 | { |
fefa31b5 DM |
2898 | for (b = EXIT_BLOCK_PTR_FOR_FN (cfun)->prev_bb; |
2899 | b != ENTRY_BLOCK_PTR_FOR_FN (cfun); b = prev_bb) | |
b5b8b0ac AO |
2900 | { |
2901 | prev_bb = b->prev_bb; | |
2902 | ||
2903 | if (!(b->flags & BB_REACHABLE)) | |
2904 | { | |
2905 | /* Speed up the removal of blocks that don't dominate | |
2906 | others. Walking backwards, this should be the common | |
2907 | case. */ | |
2908 | if (!first_dom_son (CDI_DOMINATORS, b)) | |
2909 | delete_basic_block (b); | |
2910 | else | |
2911 | { | |
9771b263 | 2912 | vec<basic_block> h |
b5b8b0ac AO |
2913 | = get_all_dominated_blocks (CDI_DOMINATORS, b); |
2914 | ||
9771b263 | 2915 | while (h.length ()) |
b5b8b0ac | 2916 | { |
9771b263 | 2917 | b = h.pop (); |
b5b8b0ac AO |
2918 | |
2919 | prev_bb = b->prev_bb; | |
0b17ab2f | 2920 | |
b5b8b0ac AO |
2921 | gcc_assert (!(b->flags & BB_REACHABLE)); |
2922 | ||
2923 | delete_basic_block (b); | |
2924 | } | |
2925 | ||
9771b263 | 2926 | h.release (); |
b5b8b0ac AO |
2927 | } |
2928 | ||
2929 | changed = true; | |
2930 | } | |
2931 | } | |
2932 | } | |
2933 | else | |
2934 | { | |
fefa31b5 DM |
2935 | for (b = EXIT_BLOCK_PTR_FOR_FN (cfun)->prev_bb; |
2936 | b != ENTRY_BLOCK_PTR_FOR_FN (cfun); b = prev_bb) | |
6a58eee9 | 2937 | { |
b5b8b0ac AO |
2938 | prev_bb = b->prev_bb; |
2939 | ||
2940 | if (!(b->flags & BB_REACHABLE)) | |
2941 | { | |
2942 | delete_basic_block (b); | |
2943 | changed = true; | |
2944 | } | |
6a58eee9 | 2945 | } |
402209ff JH |
2946 | } |
2947 | ||
2948 | if (changed) | |
2949 | tidy_fallthru_edges (); | |
2950 | return changed; | |
2951 | } | |
6fb5fa3c DB |
2952 | |
2953 | /* Delete any jump tables never referenced. We can't delete them at the | |
29f3fd5b SB |
2954 | time of removing tablejump insn as they are referenced by the preceding |
2955 | insns computing the destination, so we delay deleting and garbagecollect | |
2956 | them once life information is computed. */ | |
6fb5fa3c DB |
2957 | void |
2958 | delete_dead_jumptables (void) | |
2959 | { | |
2960 | basic_block bb; | |
2961 | ||
29f3fd5b SB |
2962 | /* A dead jump table does not belong to any basic block. Scan insns |
2963 | between two adjacent basic blocks. */ | |
11cd3bed | 2964 | FOR_EACH_BB_FN (bb, cfun) |
6fb5fa3c | 2965 | { |
da5477a9 | 2966 | rtx_insn *insn, *next; |
29f3fd5b SB |
2967 | |
2968 | for (insn = NEXT_INSN (BB_END (bb)); | |
2969 | insn && !NOTE_INSN_BASIC_BLOCK_P (insn); | |
2970 | insn = next) | |
57d6c446 | 2971 | { |
29f3fd5b SB |
2972 | next = NEXT_INSN (insn); |
2973 | if (LABEL_P (insn) | |
2974 | && LABEL_NUSES (insn) == LABEL_PRESERVE_P (insn) | |
2975 | && JUMP_TABLE_DATA_P (next)) | |
2976 | { | |
da5477a9 | 2977 | rtx_insn *label = insn, *jump = next; |
29f3fd5b SB |
2978 | |
2979 | if (dump_file) | |
2980 | fprintf (dump_file, "Dead jumptable %i removed\n", | |
2981 | INSN_UID (insn)); | |
2982 | ||
2983 | next = NEXT_INSN (next); | |
2984 | delete_insn (jump); | |
2985 | delete_insn (label); | |
2986 | } | |
6fb5fa3c DB |
2987 | } |
2988 | } | |
2989 | } | |
2990 | ||
402209ff JH |
2991 | \f |
2992 | /* Tidy the CFG by deleting unreachable code and whatnot. */ | |
2993 | ||
2994 | bool | |
d329e058 | 2995 | cleanup_cfg (int mode) |
402209ff | 2996 | { |
402209ff JH |
2997 | bool changed = false; |
2998 | ||
aeceeb06 SB |
2999 | /* Set the cfglayout mode flag here. We could update all the callers |
3000 | but that is just inconvenient, especially given that we eventually | |
3001 | want to have cfglayout mode as the default. */ | |
3002 | if (current_ir_type () == IR_RTL_CFGLAYOUT) | |
3003 | mode |= CLEANUP_CFGLAYOUT; | |
3004 | ||
402209ff | 3005 | timevar_push (TV_CLEANUP_CFG); |
3dec4024 JH |
3006 | if (delete_unreachable_blocks ()) |
3007 | { | |
3008 | changed = true; | |
3009 | /* We've possibly created trivially dead code. Cleanup it right | |
95bd1dd7 | 3010 | now to introduce more opportunities for try_optimize_cfg. */ |
6fb5fa3c | 3011 | if (!(mode & (CLEANUP_NO_INSN_DEL)) |
3dec4024 | 3012 | && !reload_completed) |
62e5bf5d | 3013 | delete_trivially_dead_insns (get_insns (), max_reg_num ()); |
3dec4024 | 3014 | } |
bf77398c ZD |
3015 | |
3016 | compact_blocks (); | |
3017 | ||
c1e3e2d9 SB |
3018 | /* To tail-merge blocks ending in the same noreturn function (e.g. |
3019 | a call to abort) we have to insert fake edges to exit. Do this | |
3020 | here once. The fake edges do not interfere with any other CFG | |
3021 | cleanups. */ | |
3022 | if (mode & CLEANUP_CROSSJUMP) | |
3023 | add_noreturn_fake_exit_edges (); | |
3024 | ||
7d817ebc DE |
3025 | if (!dbg_cnt (cfg_cleanup)) |
3026 | return changed; | |
3027 | ||
3dec4024 JH |
3028 | while (try_optimize_cfg (mode)) |
3029 | { | |
3030 | delete_unreachable_blocks (), changed = true; | |
c1e3e2d9 | 3031 | if (!(mode & CLEANUP_NO_INSN_DEL)) |
3dec4024 | 3032 | { |
c1e3e2d9 SB |
3033 | /* Try to remove some trivially dead insns when doing an expensive |
3034 | cleanup. But delete_trivially_dead_insns doesn't work after | |
3035 | reload (it only handles pseudos) and run_fast_dce is too costly | |
3036 | to run in every iteration. | |
3037 | ||
3038 | For effective cross jumping, we really want to run a fast DCE to | |
3039 | clean up any dead conditions, or they get in the way of performing | |
3040 | useful tail merges. | |
3041 | ||
3042 | Other transformations in cleanup_cfg are not so sensitive to dead | |
3043 | code, so delete_trivially_dead_insns or even doing nothing at all | |
3044 | is good enough. */ | |
3045 | if ((mode & CLEANUP_EXPENSIVE) && !reload_completed | |
3046 | && !delete_trivially_dead_insns (get_insns (), max_reg_num ())) | |
3dec4024 | 3047 | break; |
4ec5d4f5 | 3048 | if ((mode & CLEANUP_CROSSJUMP) && crossjumps_occured) |
f842d54f | 3049 | run_fast_dce (); |
3dec4024 JH |
3050 | } |
3051 | else | |
3052 | break; | |
3dec4024 | 3053 | } |
402209ff | 3054 | |
c1e3e2d9 SB |
3055 | if (mode & CLEANUP_CROSSJUMP) |
3056 | remove_fake_exit_edges (); | |
3057 | ||
29f3fd5b SB |
3058 | /* Don't call delete_dead_jumptables in cfglayout mode, because |
3059 | that function assumes that jump tables are in the insns stream. | |
3060 | But we also don't _have_ to delete dead jumptables in cfglayout | |
3061 | mode because we shouldn't even be looking at things that are | |
3062 | not in a basic block. Dead jumptables are cleaned up when | |
3063 | going out of cfglayout mode. */ | |
3064 | if (!(mode & CLEANUP_CFGLAYOUT)) | |
6fb5fa3c DB |
3065 | delete_dead_jumptables (); |
3066 | ||
7d776ee2 RG |
3067 | /* ??? We probably do this way too often. */ |
3068 | if (current_loops | |
3069 | && (changed | |
3070 | || (mode & CLEANUP_CFG_CHANGED))) | |
3071 | { | |
7d776ee2 RG |
3072 | timevar_push (TV_REPAIR_LOOPS); |
3073 | /* The above doesn't preserve dominance info if available. */ | |
3074 | gcc_assert (!dom_info_available_p (CDI_DOMINATORS)); | |
3075 | calculate_dominance_info (CDI_DOMINATORS); | |
01cb1ef5 | 3076 | fix_loop_structure (NULL); |
7d776ee2 RG |
3077 | free_dominance_info (CDI_DOMINATORS); |
3078 | timevar_pop (TV_REPAIR_LOOPS); | |
3079 | } | |
3080 | ||
402209ff JH |
3081 | timevar_pop (TV_CLEANUP_CFG); |
3082 | ||
402209ff JH |
3083 | return changed; |
3084 | } | |
ef330312 | 3085 | \f |
27a4cd48 DM |
3086 | namespace { |
3087 | ||
3088 | const pass_data pass_data_jump = | |
11a687e7 | 3089 | { |
27a4cd48 DM |
3090 | RTL_PASS, /* type */ |
3091 | "jump", /* name */ | |
3092 | OPTGROUP_NONE, /* optinfo_flags */ | |
27a4cd48 DM |
3093 | TV_JUMP, /* tv_id */ |
3094 | 0, /* properties_required */ | |
3095 | 0, /* properties_provided */ | |
3096 | 0, /* properties_destroyed */ | |
3097 | 0, /* todo_flags_start */ | |
3bea341f | 3098 | 0, /* todo_flags_finish */ |
11a687e7 | 3099 | }; |
27a4cd48 DM |
3100 | |
3101 | class pass_jump : public rtl_opt_pass | |
3102 | { | |
3103 | public: | |
c3284718 RS |
3104 | pass_jump (gcc::context *ctxt) |
3105 | : rtl_opt_pass (pass_data_jump, ctxt) | |
27a4cd48 DM |
3106 | {} |
3107 | ||
3108 | /* opt_pass methods: */ | |
be55bfe6 | 3109 | virtual unsigned int execute (function *); |
27a4cd48 DM |
3110 | |
3111 | }; // class pass_jump | |
3112 | ||
be55bfe6 TS |
3113 | unsigned int |
3114 | pass_jump::execute (function *) | |
3115 | { | |
3116 | delete_trivially_dead_insns (get_insns (), max_reg_num ()); | |
3117 | if (dump_file) | |
3118 | dump_flow_info (dump_file, dump_flags); | |
3119 | cleanup_cfg ((optimize ? CLEANUP_EXPENSIVE : 0) | |
3120 | | (flag_thread_jumps ? CLEANUP_THREADING : 0)); | |
3121 | return 0; | |
3122 | } | |
3123 | ||
27a4cd48 DM |
3124 | } // anon namespace |
3125 | ||
3126 | rtl_opt_pass * | |
3127 | make_pass_jump (gcc::context *ctxt) | |
3128 | { | |
3129 | return new pass_jump (ctxt); | |
3130 | } | |
11a687e7 | 3131 | \f |
27a4cd48 DM |
3132 | namespace { |
3133 | ||
3134 | const pass_data pass_data_jump2 = | |
ef330312 | 3135 | { |
27a4cd48 DM |
3136 | RTL_PASS, /* type */ |
3137 | "jump2", /* name */ | |
3138 | OPTGROUP_NONE, /* optinfo_flags */ | |
27a4cd48 DM |
3139 | TV_JUMP, /* tv_id */ |
3140 | 0, /* properties_required */ | |
3141 | 0, /* properties_provided */ | |
3142 | 0, /* properties_destroyed */ | |
3143 | 0, /* todo_flags_start */ | |
3bea341f | 3144 | 0, /* todo_flags_finish */ |
ef330312 | 3145 | }; |
27a4cd48 DM |
3146 | |
3147 | class pass_jump2 : public rtl_opt_pass | |
3148 | { | |
3149 | public: | |
c3284718 RS |
3150 | pass_jump2 (gcc::context *ctxt) |
3151 | : rtl_opt_pass (pass_data_jump2, ctxt) | |
27a4cd48 DM |
3152 | {} |
3153 | ||
3154 | /* opt_pass methods: */ | |
be55bfe6 TS |
3155 | virtual unsigned int execute (function *) |
3156 | { | |
3157 | cleanup_cfg (flag_crossjumping ? CLEANUP_CROSSJUMP : 0); | |
3158 | return 0; | |
3159 | } | |
27a4cd48 DM |
3160 | |
3161 | }; // class pass_jump2 | |
3162 | ||
3163 | } // anon namespace | |
3164 | ||
3165 | rtl_opt_pass * | |
3166 | make_pass_jump2 (gcc::context *ctxt) | |
3167 | { | |
3168 | return new pass_jump2 (ctxt); | |
3169 | } |