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65f34de5 | 1 | /* Control flow optimization code for GNU compiler. |
d353bf18 | 2 | Copyright (C) 1987-2015 Free Software Foundation, Inc. |
65f34de5 | 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 | |
8c4c00c1 | 8 | Software Foundation; either version 3, or (at your option) any later |
65f34de5 | 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 | |
8c4c00c1 | 17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ | |
65f34de5 | 19 | |
365db11e | 20 | /* This file contains optimizer of the control flow. The main entry point is |
65f34de5 | 21 | cleanup_cfg. Following optimizations are performed: |
22 | ||
23 | - Unreachable blocks removal | |
3927afe0 | 24 | - Edge forwarding (edge to the forwarder block is forwarded to its |
4a82352a | 25 | successor. Simplification of the branch instruction is performed by |
65f34de5 | 26 | underlying infrastructure so branch can be converted to simplejump or |
35a3065a | 27 | eliminated). |
65f34de5 | 28 | - Cross jumping (tail merging) |
29 | - Conditional jump-around-simplejump simplification | |
30 | - Basic block merging. */ | |
31 | ||
32 | #include "config.h" | |
33 | #include "system.h" | |
805e22b2 | 34 | #include "coretypes.h" |
35 | #include "tm.h" | |
65f34de5 | 36 | #include "rtl.h" |
b20a8bb4 | 37 | #include "hash-set.h" |
38 | #include "machmode.h" | |
39 | #include "vec.h" | |
40 | #include "double-int.h" | |
41 | #include "input.h" | |
42 | #include "alias.h" | |
43 | #include "symtab.h" | |
44 | #include "wide-int.h" | |
45 | #include "inchash.h" | |
41a8aa41 | 46 | #include "tree.h" |
65f34de5 | 47 | #include "hard-reg-set.h" |
42fe97ed | 48 | #include "regs.h" |
65f34de5 | 49 | #include "insn-config.h" |
50 | #include "flags.h" | |
51 | #include "recog.h" | |
0b205f4c | 52 | #include "diagnostic-core.h" |
8cd78fca | 53 | #include "cselib.h" |
2a5b4716 | 54 | #include "params.h" |
20eee3f6 | 55 | #include "tm_p.h" |
e27e52e0 | 56 | #include "target.h" |
a3020f2f | 57 | #include "hashtab.h" |
23a070f3 | 58 | #include "function.h" /* For inline functions in emit-rtl.h they need crtl. */ |
4c74e6d9 | 59 | #include "emit-rtl.h" |
77fce4cd | 60 | #include "tree-pass.h" |
61 | #include "cfgloop.h" | |
d53441c8 | 62 | #include "function.h" |
63 | #include "statistics.h" | |
64 | #include "real.h" | |
65 | #include "fixed-value.h" | |
66 | #include "expmed.h" | |
67 | #include "dojump.h" | |
68 | #include "explow.h" | |
69 | #include "calls.h" | |
70 | #include "varasm.h" | |
71 | #include "stmt.h" | |
77fce4cd | 72 | #include "expr.h" |
94ea8568 | 73 | #include "dominance.h" |
74 | #include "cfg.h" | |
75 | #include "cfgrtl.h" | |
76 | #include "cfganal.h" | |
77 | #include "cfgbuild.h" | |
78 | #include "cfgcleanup.h" | |
79 | #include "predict.h" | |
80 | #include "basic-block.h" | |
3072d30e | 81 | #include "df.h" |
1ae2ffa7 | 82 | #include "dce.h" |
4ff06051 | 83 | #include "dbgcnt.h" |
97e3e0ac | 84 | #include "rtl-iter.h" |
65f34de5 | 85 | |
4fe5a223 | 86 | #define FORWARDER_BLOCK_P(BB) ((BB)->flags & BB_FORWARDER_BLOCK) |
a0c938f0 | 87 | |
10d3796f | 88 | /* Set to true when we are running first pass of try_optimize_cfg loop. */ |
89 | static bool first_pass; | |
1ae2ffa7 | 90 | |
9d75589a | 91 | /* Set to true if crossjumps occurred in the latest run of try_optimize_cfg. */ |
1ae2ffa7 | 92 | static bool crossjumps_occured; |
93 | ||
bc6adae4 | 94 | /* Set to true if we couldn't run an optimization due to stale liveness |
95 | information; we should run df_analyze to enable more opportunities. */ | |
96 | static bool block_was_dirty; | |
97 | ||
0f38cfdd | 98 | static bool try_crossjump_to_edge (int, edge, edge, enum replace_direction); |
4c9e08a4 | 99 | static bool try_crossjump_bb (int, basic_block); |
1d133110 | 100 | static bool outgoing_edges_match (int, basic_block, basic_block); |
c093ac49 | 101 | static enum replace_direction old_insns_match_p (int, rtx_insn *, rtx_insn *); |
4c9e08a4 | 102 | |
4c9e08a4 | 103 | static void merge_blocks_move_predecessor_nojumps (basic_block, basic_block); |
104 | static void merge_blocks_move_successor_nojumps (basic_block, basic_block); | |
4c9e08a4 | 105 | static bool try_optimize_cfg (int); |
106 | static bool try_simplify_condjump (basic_block); | |
107 | static bool try_forward_edges (int, basic_block); | |
3072d30e | 108 | static edge thread_jump (edge, basic_block); |
4c9e08a4 | 109 | static bool mark_effect (rtx, bitmap); |
110 | static void notice_new_block (basic_block); | |
111 | static void update_forwarder_flag (basic_block); | |
1d133110 | 112 | static void merge_memattrs (rtx, rtx); |
33dbe4d1 | 113 | \f |
114 | /* Set flags for newly created block. */ | |
115 | ||
116 | static void | |
4c9e08a4 | 117 | notice_new_block (basic_block bb) |
33dbe4d1 | 118 | { |
119 | if (!bb) | |
120 | return; | |
5cc577b6 | 121 | |
33dbe4d1 | 122 | if (forwarder_block_p (bb)) |
4fe5a223 | 123 | bb->flags |= BB_FORWARDER_BLOCK; |
33dbe4d1 | 124 | } |
125 | ||
126 | /* Recompute forwarder flag after block has been modified. */ | |
127 | ||
128 | static void | |
4c9e08a4 | 129 | update_forwarder_flag (basic_block bb) |
33dbe4d1 | 130 | { |
131 | if (forwarder_block_p (bb)) | |
4fe5a223 | 132 | bb->flags |= BB_FORWARDER_BLOCK; |
33dbe4d1 | 133 | else |
4fe5a223 | 134 | bb->flags &= ~BB_FORWARDER_BLOCK; |
33dbe4d1 | 135 | } |
65f34de5 | 136 | \f |
137 | /* Simplify a conditional jump around an unconditional jump. | |
138 | Return true if something changed. */ | |
139 | ||
140 | static bool | |
4c9e08a4 | 141 | try_simplify_condjump (basic_block cbranch_block) |
65f34de5 | 142 | { |
143 | basic_block jump_block, jump_dest_block, cbranch_dest_block; | |
144 | edge cbranch_jump_edge, cbranch_fallthru_edge; | |
c093ac49 | 145 | rtx_insn *cbranch_insn; |
65f34de5 | 146 | |
147 | /* Verify that there are exactly two successors. */ | |
cd665a06 | 148 | if (EDGE_COUNT (cbranch_block->succs) != 2) |
65f34de5 | 149 | return false; |
150 | ||
151 | /* Verify that we've got a normal conditional branch at the end | |
152 | of the block. */ | |
5496dbfc | 153 | cbranch_insn = BB_END (cbranch_block); |
65f34de5 | 154 | if (!any_condjump_p (cbranch_insn)) |
155 | return false; | |
156 | ||
157 | cbranch_fallthru_edge = FALLTHRU_EDGE (cbranch_block); | |
158 | cbranch_jump_edge = BRANCH_EDGE (cbranch_block); | |
159 | ||
160 | /* The next block must not have multiple predecessors, must not | |
161 | be the last block in the function, and must contain just the | |
162 | unconditional jump. */ | |
163 | jump_block = cbranch_fallthru_edge->dest; | |
ea091dfd | 164 | if (!single_pred_p (jump_block) |
34154e27 | 165 | || jump_block->next_bb == EXIT_BLOCK_PTR_FOR_FN (cfun) |
33dbe4d1 | 166 | || !FORWARDER_BLOCK_P (jump_block)) |
65f34de5 | 167 | return false; |
ea091dfd | 168 | jump_dest_block = single_succ (jump_block); |
65f34de5 | 169 | |
4f18499c | 170 | /* If we are partitioning hot/cold basic blocks, we don't want to |
171 | mess up unconditional or indirect jumps that cross between hot | |
a0c938f0 | 172 | and cold sections. |
1118aef7 | 173 | |
174 | Basic block partitioning may result in some jumps that appear to | |
a0c938f0 | 175 | be optimizable (or blocks that appear to be mergeable), but which really |
176 | must be left untouched (they are required to make it safely across | |
177 | partition boundaries). See the comments at the top of | |
1118aef7 | 178 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
4f18499c | 179 | |
1897b881 | 180 | if (BB_PARTITION (jump_block) != BB_PARTITION (jump_dest_block) |
181 | || (cbranch_jump_edge->flags & EDGE_CROSSING)) | |
4f18499c | 182 | return false; |
183 | ||
65f34de5 | 184 | /* The conditional branch must target the block after the |
185 | unconditional branch. */ | |
186 | cbranch_dest_block = cbranch_jump_edge->dest; | |
187 | ||
34154e27 | 188 | if (cbranch_dest_block == EXIT_BLOCK_PTR_FOR_FN (cfun) |
f3fbd62d | 189 | || !can_fallthru (jump_block, cbranch_dest_block)) |
65f34de5 | 190 | return false; |
191 | ||
b36d64df | 192 | /* Invert the conditional branch. */ |
193 | if (!invert_jump (cbranch_insn, block_label (jump_dest_block), 0)) | |
194 | return false; | |
65f34de5 | 195 | |
450d042a | 196 | if (dump_file) |
197 | fprintf (dump_file, "Simplifying condjump %i around jump %i\n", | |
5496dbfc | 198 | INSN_UID (cbranch_insn), INSN_UID (BB_END (jump_block))); |
65f34de5 | 199 | |
200 | /* Success. Update the CFG to match. Note that after this point | |
201 | the edge variable names appear backwards; the redirection is done | |
202 | this way to preserve edge profile data. */ | |
203 | cbranch_jump_edge = redirect_edge_succ_nodup (cbranch_jump_edge, | |
204 | cbranch_dest_block); | |
205 | cbranch_fallthru_edge = redirect_edge_succ_nodup (cbranch_fallthru_edge, | |
206 | jump_dest_block); | |
207 | cbranch_jump_edge->flags |= EDGE_FALLTHRU; | |
208 | cbranch_fallthru_edge->flags &= ~EDGE_FALLTHRU; | |
f884e43f | 209 | update_br_prob_note (cbranch_block); |
65f34de5 | 210 | |
211 | /* Delete the block with the unconditional jump, and clean up the mess. */ | |
5f5d4cd1 | 212 | delete_basic_block (jump_block); |
213 | tidy_fallthru_edge (cbranch_jump_edge); | |
fe4306df | 214 | update_forwarder_flag (cbranch_block); |
65f34de5 | 215 | |
216 | return true; | |
217 | } | |
218 | \f | |
8cd78fca | 219 | /* Attempt to prove that operation is NOOP using CSElib or mark the effect |
220 | on register. Used by jump threading. */ | |
5cc577b6 | 221 | |
8cd78fca | 222 | static bool |
4c9e08a4 | 223 | mark_effect (rtx exp, regset nonequal) |
8cd78fca | 224 | { |
20eee3f6 | 225 | int regno; |
226 | rtx dest; | |
8cd78fca | 227 | switch (GET_CODE (exp)) |
228 | { | |
229 | /* In case we do clobber the register, mark it as equal, as we know the | |
a0c938f0 | 230 | value is dead so it don't have to match. */ |
db34a109 | 231 | case CLOBBER: |
232 | if (REG_P (XEXP (exp, 0))) | |
233 | { | |
234 | dest = XEXP (exp, 0); | |
235 | regno = REGNO (dest); | |
771d4616 | 236 | if (HARD_REGISTER_NUM_P (regno)) |
237 | bitmap_clear_range (nonequal, regno, | |
238 | hard_regno_nregs[regno][GET_MODE (dest)]); | |
239 | else | |
240 | bitmap_clear_bit (nonequal, regno); | |
db34a109 | 241 | } |
242 | return false; | |
5cc577b6 | 243 | |
db34a109 | 244 | case SET: |
245 | if (rtx_equal_for_cselib_p (SET_DEST (exp), SET_SRC (exp))) | |
8cd78fca | 246 | return false; |
db34a109 | 247 | dest = SET_DEST (exp); |
248 | if (dest == pc_rtx) | |
8cd78fca | 249 | return false; |
db34a109 | 250 | if (!REG_P (dest)) |
251 | return true; | |
252 | regno = REGNO (dest); | |
771d4616 | 253 | if (HARD_REGISTER_NUM_P (regno)) |
254 | bitmap_set_range (nonequal, regno, | |
255 | hard_regno_nregs[regno][GET_MODE (dest)]); | |
256 | else | |
257 | bitmap_set_bit (nonequal, regno); | |
db34a109 | 258 | return false; |
259 | ||
260 | default: | |
261 | return false; | |
8cd78fca | 262 | } |
263 | } | |
4ccdad8e | 264 | |
97e3e0ac | 265 | /* Return true if X contains a register in NONEQUAL. */ |
266 | static bool | |
267 | mentions_nonequal_regs (const_rtx x, regset nonequal) | |
4ccdad8e | 268 | { |
97e3e0ac | 269 | subrtx_iterator::array_type array; |
270 | FOR_EACH_SUBRTX (iter, array, x, NONCONST) | |
4ccdad8e | 271 | { |
97e3e0ac | 272 | const_rtx x = *iter; |
273 | if (REG_P (x)) | |
4ccdad8e | 274 | { |
6a298741 | 275 | unsigned int end_regno = END_REGNO (x); |
276 | for (unsigned int regno = REGNO (x); regno < end_regno; ++regno) | |
277 | if (REGNO_REG_SET_P (nonequal, regno)) | |
278 | return true; | |
4ccdad8e | 279 | } |
280 | } | |
97e3e0ac | 281 | return false; |
4ccdad8e | 282 | } |
97e3e0ac | 283 | |
8cd78fca | 284 | /* Attempt to prove that the basic block B will have no side effects and |
d716ce75 | 285 | always continues in the same edge if reached via E. Return the edge |
8cd78fca | 286 | if exist, NULL otherwise. */ |
287 | ||
288 | static edge | |
3072d30e | 289 | thread_jump (edge e, basic_block b) |
8cd78fca | 290 | { |
c093ac49 | 291 | rtx set1, set2, cond1, cond2; |
292 | rtx_insn *insn; | |
8cd78fca | 293 | enum rtx_code code1, code2, reversed_code2; |
294 | bool reverse1 = false; | |
4f917ffe | 295 | unsigned i; |
8cd78fca | 296 | regset nonequal; |
297 | bool failed = false; | |
8c97cf13 | 298 | reg_set_iterator rsi; |
8cd78fca | 299 | |
4fe5a223 | 300 | if (b->flags & BB_NONTHREADABLE_BLOCK) |
73e2b81c | 301 | return NULL; |
302 | ||
8cd78fca | 303 | /* At the moment, we do handle only conditional jumps, but later we may |
304 | want to extend this code to tablejumps and others. */ | |
cd665a06 | 305 | if (EDGE_COUNT (e->src->succs) != 2) |
8cd78fca | 306 | return NULL; |
cd665a06 | 307 | if (EDGE_COUNT (b->succs) != 2) |
73e2b81c | 308 | { |
4fe5a223 | 309 | b->flags |= BB_NONTHREADABLE_BLOCK; |
73e2b81c | 310 | return NULL; |
311 | } | |
8cd78fca | 312 | |
313 | /* Second branch must end with onlyjump, as we will eliminate the jump. */ | |
5496dbfc | 314 | if (!any_condjump_p (BB_END (e->src))) |
8cd78fca | 315 | return NULL; |
db34a109 | 316 | |
5496dbfc | 317 | if (!any_condjump_p (BB_END (b)) || !onlyjump_p (BB_END (b))) |
73e2b81c | 318 | { |
4fe5a223 | 319 | b->flags |= BB_NONTHREADABLE_BLOCK; |
73e2b81c | 320 | return NULL; |
321 | } | |
8cd78fca | 322 | |
5496dbfc | 323 | set1 = pc_set (BB_END (e->src)); |
324 | set2 = pc_set (BB_END (b)); | |
8cd78fca | 325 | if (((e->flags & EDGE_FALLTHRU) != 0) |
dd782271 | 326 | != (XEXP (SET_SRC (set1), 1) == pc_rtx)) |
8cd78fca | 327 | reverse1 = true; |
328 | ||
329 | cond1 = XEXP (SET_SRC (set1), 0); | |
330 | cond2 = XEXP (SET_SRC (set2), 0); | |
331 | if (reverse1) | |
5496dbfc | 332 | code1 = reversed_comparison_code (cond1, BB_END (e->src)); |
8cd78fca | 333 | else |
334 | code1 = GET_CODE (cond1); | |
335 | ||
336 | code2 = GET_CODE (cond2); | |
5496dbfc | 337 | reversed_code2 = reversed_comparison_code (cond2, BB_END (b)); |
8cd78fca | 338 | |
339 | if (!comparison_dominates_p (code1, code2) | |
340 | && !comparison_dominates_p (code1, reversed_code2)) | |
341 | return NULL; | |
342 | ||
343 | /* Ensure that the comparison operators are equivalent. | |
d716ce75 | 344 | ??? This is far too pessimistic. We should allow swapped operands, |
8cd78fca | 345 | different CCmodes, or for example comparisons for interval, that |
346 | dominate even when operands are not equivalent. */ | |
347 | if (!rtx_equal_p (XEXP (cond1, 0), XEXP (cond2, 0)) | |
348 | || !rtx_equal_p (XEXP (cond1, 1), XEXP (cond2, 1))) | |
349 | return NULL; | |
350 | ||
351 | /* Short circuit cases where block B contains some side effects, as we can't | |
352 | safely bypass it. */ | |
5496dbfc | 353 | for (insn = NEXT_INSN (BB_HEAD (b)); insn != NEXT_INSN (BB_END (b)); |
8cd78fca | 354 | insn = NEXT_INSN (insn)) |
355 | if (INSN_P (insn) && side_effects_p (PATTERN (insn))) | |
73e2b81c | 356 | { |
4fe5a223 | 357 | b->flags |= BB_NONTHREADABLE_BLOCK; |
73e2b81c | 358 | return NULL; |
359 | } | |
8cd78fca | 360 | |
35af0188 | 361 | cselib_init (0); |
8cd78fca | 362 | |
363 | /* First process all values computed in the source basic block. */ | |
4f917ffe | 364 | for (insn = NEXT_INSN (BB_HEAD (e->src)); |
365 | insn != NEXT_INSN (BB_END (e->src)); | |
8cd78fca | 366 | insn = NEXT_INSN (insn)) |
367 | if (INSN_P (insn)) | |
368 | cselib_process_insn (insn); | |
369 | ||
27335ffd | 370 | nonequal = BITMAP_ALLOC (NULL); |
8cd78fca | 371 | CLEAR_REG_SET (nonequal); |
5cc577b6 | 372 | |
8cd78fca | 373 | /* Now assume that we've continued by the edge E to B and continue |
374 | processing as if it were same basic block. | |
8cd78fca | 375 | Our goal is to prove that whole block is an NOOP. */ |
5cc577b6 | 376 | |
4f917ffe | 377 | for (insn = NEXT_INSN (BB_HEAD (b)); |
378 | insn != NEXT_INSN (BB_END (b)) && !failed; | |
8cd78fca | 379 | insn = NEXT_INSN (insn)) |
db34a109 | 380 | { |
381 | if (INSN_P (insn)) | |
382 | { | |
383 | rtx pat = PATTERN (insn); | |
384 | ||
385 | if (GET_CODE (pat) == PARALLEL) | |
386 | { | |
4f917ffe | 387 | for (i = 0; i < (unsigned)XVECLEN (pat, 0); i++) |
db34a109 | 388 | failed |= mark_effect (XVECEXP (pat, 0, i), nonequal); |
389 | } | |
390 | else | |
391 | failed |= mark_effect (pat, nonequal); | |
392 | } | |
5cc577b6 | 393 | |
db34a109 | 394 | cselib_process_insn (insn); |
395 | } | |
8cd78fca | 396 | |
397 | /* Later we should clear nonequal of dead registers. So far we don't | |
398 | have life information in cfg_cleanup. */ | |
399 | if (failed) | |
73e2b81c | 400 | { |
4fe5a223 | 401 | b->flags |= BB_NONTHREADABLE_BLOCK; |
73e2b81c | 402 | goto failed_exit; |
403 | } | |
8cd78fca | 404 | |
4ccdad8e | 405 | /* cond2 must not mention any register that is not equal to the |
406 | former block. */ | |
97e3e0ac | 407 | if (mentions_nonequal_regs (cond2, nonequal)) |
4ccdad8e | 408 | goto failed_exit; |
409 | ||
8c97cf13 | 410 | EXECUTE_IF_SET_IN_REG_SET (nonequal, 0, i, rsi) |
411 | goto failed_exit; | |
8cd78fca | 412 | |
27335ffd | 413 | BITMAP_FREE (nonequal); |
8cd78fca | 414 | cselib_finish (); |
415 | if ((comparison_dominates_p (code1, code2) != 0) | |
148444fb | 416 | != (XEXP (SET_SRC (set2), 1) == pc_rtx)) |
8cd78fca | 417 | return BRANCH_EDGE (b); |
418 | else | |
419 | return FALLTHRU_EDGE (b); | |
420 | ||
421 | failed_exit: | |
27335ffd | 422 | BITMAP_FREE (nonequal); |
8cd78fca | 423 | cselib_finish (); |
424 | return NULL; | |
425 | } | |
426 | \f | |
65f34de5 | 427 | /* Attempt to forward edges leaving basic block B. |
4a82352a | 428 | Return true if successful. */ |
65f34de5 | 429 | |
430 | static bool | |
4c9e08a4 | 431 | try_forward_edges (int mode, basic_block b) |
65f34de5 | 432 | { |
433 | bool changed = false; | |
cd665a06 | 434 | edge_iterator ei; |
435 | edge e, *threaded_edges = NULL; | |
65f34de5 | 436 | |
4f18499c | 437 | /* If we are partitioning hot/cold basic blocks, we don't want to |
438 | mess up unconditional or indirect jumps that cross between hot | |
a0c938f0 | 439 | and cold sections. |
440 | ||
1118aef7 | 441 | Basic block partitioning may result in some jumps that appear to |
f0b5f617 | 442 | be optimizable (or blocks that appear to be mergeable), but which really |
443 | must be left untouched (they are required to make it safely across | |
a0c938f0 | 444 | partition boundaries). See the comments at the top of |
1118aef7 | 445 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
446 | ||
8f869004 | 447 | if (JUMP_P (BB_END (b)) && CROSSING_JUMP_P (BB_END (b))) |
4f18499c | 448 | return false; |
449 | ||
cd665a06 | 450 | for (ei = ei_start (b->succs); (e = ei_safe_edge (ei)); ) |
65f34de5 | 451 | { |
452 | basic_block target, first; | |
36ebb5b6 | 453 | location_t goto_locus; |
454 | int counter; | |
8cd78fca | 455 | bool threaded = false; |
d2855ea6 | 456 | int nthreaded_edges = 0; |
bc6adae4 | 457 | bool may_thread = first_pass || (b->flags & BB_MODIFIED) != 0; |
65f34de5 | 458 | |
65f34de5 | 459 | /* Skip complex edges because we don't know how to update them. |
460 | ||
a0c938f0 | 461 | Still handle fallthru edges, as we can succeed to forward fallthru |
462 | edge to the same place as the branch edge of conditional branch | |
463 | and turn conditional branch to an unconditional branch. */ | |
65f34de5 | 464 | if (e->flags & EDGE_COMPLEX) |
cd665a06 | 465 | { |
466 | ei_next (&ei); | |
467 | continue; | |
468 | } | |
65f34de5 | 469 | |
470 | target = first = e->dest; | |
4d2e5d52 | 471 | counter = NUM_FIXED_BLOCKS; |
9c388755 | 472 | goto_locus = e->goto_locus; |
65f34de5 | 473 | |
065efcb1 | 474 | /* If we are partitioning hot/cold basic_blocks, we don't want to mess |
1118aef7 | 475 | up jumps that cross between hot/cold sections. |
476 | ||
477 | Basic block partitioning may result in some jumps that appear | |
a0c938f0 | 478 | to be optimizable (or blocks that appear to be mergeable), but which |
479 | really must be left untouched (they are required to make it safely | |
1118aef7 | 480 | across partition boundaries). See the comments at the top of |
481 | bb-reorder.c:partition_hot_cold_basic_blocks for complete | |
482 | details. */ | |
065efcb1 | 483 | |
34154e27 | 484 | if (first != EXIT_BLOCK_PTR_FOR_FN (cfun) |
8f869004 | 485 | && JUMP_P (BB_END (first)) |
486 | && CROSSING_JUMP_P (BB_END (first))) | |
aa78dca5 | 487 | return changed; |
065efcb1 | 488 | |
a28770e1 | 489 | while (counter < n_basic_blocks_for_fn (cfun)) |
65f34de5 | 490 | { |
8cd78fca | 491 | basic_block new_target = NULL; |
492 | bool new_target_threaded = false; | |
bc6adae4 | 493 | may_thread |= (target->flags & BB_MODIFIED) != 0; |
8cd78fca | 494 | |
495 | if (FORWARDER_BLOCK_P (target) | |
a0c938f0 | 496 | && !(single_succ_edge (target)->flags & EDGE_CROSSING) |
34154e27 | 497 | && single_succ (target) != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
8cd78fca | 498 | { |
499 | /* Bypass trivial infinite loops. */ | |
ea091dfd | 500 | new_target = single_succ (target); |
501 | if (target == new_target) | |
a28770e1 | 502 | counter = n_basic_blocks_for_fn (cfun); |
9c388755 | 503 | else if (!optimize) |
504 | { | |
505 | /* When not optimizing, ensure that edges or forwarder | |
506 | blocks with different locus are not optimized out. */ | |
36ebb5b6 | 507 | location_t new_locus = single_succ_edge (target)->goto_locus; |
508 | location_t locus = goto_locus; | |
9c388755 | 509 | |
0e7ae557 | 510 | if (LOCATION_LOCUS (new_locus) != UNKNOWN_LOCATION |
511 | && LOCATION_LOCUS (locus) != UNKNOWN_LOCATION | |
5169661d | 512 | && new_locus != locus) |
18b762f0 | 513 | new_target = NULL; |
514 | else | |
9c388755 | 515 | { |
0e7ae557 | 516 | if (LOCATION_LOCUS (new_locus) != UNKNOWN_LOCATION) |
18b762f0 | 517 | locus = new_locus; |
9c388755 | 518 | |
c093ac49 | 519 | rtx_insn *last = BB_END (target); |
4fba8976 | 520 | if (DEBUG_INSN_P (last)) |
521 | last = prev_nondebug_insn (last); | |
0e7ae557 | 522 | if (last && INSN_P (last)) |
523 | new_locus = INSN_LOCATION (last); | |
524 | else | |
525 | new_locus = UNKNOWN_LOCATION; | |
4fba8976 | 526 | |
0e7ae557 | 527 | if (LOCATION_LOCUS (new_locus) != UNKNOWN_LOCATION |
528 | && LOCATION_LOCUS (locus) != UNKNOWN_LOCATION | |
5169661d | 529 | && new_locus != locus) |
18b762f0 | 530 | new_target = NULL; |
531 | else | |
532 | { | |
0e7ae557 | 533 | if (LOCATION_LOCUS (new_locus) != UNKNOWN_LOCATION) |
18b762f0 | 534 | locus = new_locus; |
535 | ||
536 | goto_locus = locus; | |
537 | } | |
9c388755 | 538 | } |
539 | } | |
8cd78fca | 540 | } |
5cc577b6 | 541 | |
8cd78fca | 542 | /* Allow to thread only over one edge at time to simplify updating |
543 | of probabilities. */ | |
10d3796f | 544 | else if ((mode & CLEANUP_THREADING) && may_thread) |
8cd78fca | 545 | { |
3072d30e | 546 | edge t = thread_jump (e, target); |
309306ce | 547 | if (t) |
8cd78fca | 548 | { |
d2855ea6 | 549 | if (!threaded_edges) |
a28770e1 | 550 | threaded_edges = XNEWVEC (edge, |
551 | n_basic_blocks_for_fn (cfun)); | |
acf4e6a8 | 552 | else |
553 | { | |
554 | int i; | |
555 | ||
556 | /* Detect an infinite loop across blocks not | |
557 | including the start block. */ | |
558 | for (i = 0; i < nthreaded_edges; ++i) | |
559 | if (threaded_edges[i] == t) | |
560 | break; | |
561 | if (i < nthreaded_edges) | |
e9bc5a2d | 562 | { |
a28770e1 | 563 | counter = n_basic_blocks_for_fn (cfun); |
e9bc5a2d | 564 | break; |
565 | } | |
acf4e6a8 | 566 | } |
567 | ||
568 | /* Detect an infinite loop across the start block. */ | |
569 | if (t->dest == b) | |
570 | break; | |
571 | ||
a28770e1 | 572 | gcc_assert (nthreaded_edges |
573 | < (n_basic_blocks_for_fn (cfun) | |
574 | - NUM_FIXED_BLOCKS)); | |
309306ce | 575 | threaded_edges[nthreaded_edges++] = t; |
acf4e6a8 | 576 | |
577 | new_target = t->dest; | |
578 | new_target_threaded = true; | |
8cd78fca | 579 | } |
580 | } | |
5cc577b6 | 581 | |
8cd78fca | 582 | if (!new_target) |
583 | break; | |
65f34de5 | 584 | |
8cd78fca | 585 | counter++; |
586 | target = new_target; | |
587 | threaded |= new_target_threaded; | |
db34a109 | 588 | } |
65f34de5 | 589 | |
a28770e1 | 590 | if (counter >= n_basic_blocks_for_fn (cfun)) |
65f34de5 | 591 | { |
450d042a | 592 | if (dump_file) |
593 | fprintf (dump_file, "Infinite loop in BB %i.\n", | |
b3d6de89 | 594 | target->index); |
65f34de5 | 595 | } |
596 | else if (target == first) | |
597 | ; /* We didn't do anything. */ | |
598 | else | |
599 | { | |
600 | /* Save the values now, as the edge may get removed. */ | |
601 | gcov_type edge_count = e->count; | |
602 | int edge_probability = e->probability; | |
8cd78fca | 603 | int edge_frequency; |
309306ce | 604 | int n = 0; |
65f34de5 | 605 | |
9c388755 | 606 | e->goto_locus = goto_locus; |
607 | ||
8963581a | 608 | /* Don't force if target is exit block. */ |
34154e27 | 609 | if (threaded && target != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
65f34de5 | 610 | { |
8cd78fca | 611 | notice_new_block (redirect_edge_and_branch_force (e, target)); |
450d042a | 612 | if (dump_file) |
613 | fprintf (dump_file, "Conditionals threaded.\n"); | |
65f34de5 | 614 | } |
8cd78fca | 615 | else if (!redirect_edge_and_branch (e, target)) |
65f34de5 | 616 | { |
450d042a | 617 | if (dump_file) |
618 | fprintf (dump_file, | |
5cc577b6 | 619 | "Forwarding edge %i->%i to %i failed.\n", |
b3d6de89 | 620 | b->index, e->dest->index, target->index); |
cd665a06 | 621 | ei_next (&ei); |
8cd78fca | 622 | continue; |
65f34de5 | 623 | } |
5cc577b6 | 624 | |
8cd78fca | 625 | /* We successfully forwarded the edge. Now update profile |
626 | data: for each edge we traversed in the chain, remove | |
627 | the original edge's execution count. */ | |
f9d4b7f4 | 628 | edge_frequency = apply_probability (b->frequency, edge_probability); |
8cd78fca | 629 | |
8cd78fca | 630 | do |
631 | { | |
632 | edge t; | |
5cc577b6 | 633 | |
ea091dfd | 634 | if (!single_succ_p (first)) |
acf4e6a8 | 635 | { |
cc636d56 | 636 | gcc_assert (n < nthreaded_edges); |
acf4e6a8 | 637 | t = threaded_edges [n++]; |
cc636d56 | 638 | gcc_assert (t->src == first); |
615dd397 | 639 | update_bb_profile_for_threading (first, edge_frequency, |
640 | edge_count, t); | |
f884e43f | 641 | update_br_prob_note (first); |
acf4e6a8 | 642 | } |
8cd78fca | 643 | else |
d2855ea6 | 644 | { |
615dd397 | 645 | first->count -= edge_count; |
646 | if (first->count < 0) | |
647 | first->count = 0; | |
648 | first->frequency -= edge_frequency; | |
649 | if (first->frequency < 0) | |
650 | first->frequency = 0; | |
d2855ea6 | 651 | /* It is possible that as the result of |
652 | threading we've removed edge as it is | |
653 | threaded to the fallthru edge. Avoid | |
654 | getting out of sync. */ | |
655 | if (n < nthreaded_edges | |
656 | && first == threaded_edges [n]->src) | |
657 | n++; | |
ea091dfd | 658 | t = single_succ_edge (first); |
db34a109 | 659 | } |
5cc577b6 | 660 | |
f884e43f | 661 | t->count -= edge_count; |
662 | if (t->count < 0) | |
663 | t->count = 0; | |
8cd78fca | 664 | first = t->dest; |
665 | } | |
666 | while (first != target); | |
667 | ||
668 | changed = true; | |
cd665a06 | 669 | continue; |
65f34de5 | 670 | } |
cd665a06 | 671 | ei_next (&ei); |
65f34de5 | 672 | } |
673 | ||
dd045aee | 674 | free (threaded_edges); |
65f34de5 | 675 | return changed; |
676 | } | |
677 | \f | |
65f34de5 | 678 | |
679 | /* Blocks A and B are to be merged into a single block. A has no incoming | |
680 | fallthru edge, so it can be moved before B without adding or modifying | |
681 | any jumps (aside from the jump from A to B). */ | |
682 | ||
e76f35e8 | 683 | static void |
4c9e08a4 | 684 | merge_blocks_move_predecessor_nojumps (basic_block a, basic_block b) |
65f34de5 | 685 | { |
c093ac49 | 686 | rtx_insn *barrier; |
65f34de5 | 687 | |
4f18499c | 688 | /* If we are partitioning hot/cold basic blocks, we don't want to |
689 | mess up unconditional or indirect jumps that cross between hot | |
1118aef7 | 690 | and cold sections. |
a0c938f0 | 691 | |
1118aef7 | 692 | Basic block partitioning may result in some jumps that appear to |
a0c938f0 | 693 | be optimizable (or blocks that appear to be mergeable), but which really |
694 | must be left untouched (they are required to make it safely across | |
695 | partition boundaries). See the comments at the top of | |
1118aef7 | 696 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
697 | ||
1897b881 | 698 | if (BB_PARTITION (a) != BB_PARTITION (b)) |
4f18499c | 699 | return; |
700 | ||
5496dbfc | 701 | barrier = next_nonnote_insn (BB_END (a)); |
cc636d56 | 702 | gcc_assert (BARRIER_P (barrier)); |
e4bf866d | 703 | delete_insn (barrier); |
65f34de5 | 704 | |
65f34de5 | 705 | /* Scramble the insn chain. */ |
5496dbfc | 706 | if (BB_END (a) != PREV_INSN (BB_HEAD (b))) |
707 | reorder_insns_nobb (BB_HEAD (a), BB_END (a), PREV_INSN (BB_HEAD (b))); | |
3072d30e | 708 | df_set_bb_dirty (a); |
65f34de5 | 709 | |
450d042a | 710 | if (dump_file) |
711 | fprintf (dump_file, "Moved block %d before %d and merged.\n", | |
b3d6de89 | 712 | a->index, b->index); |
65f34de5 | 713 | |
3c0a32c9 | 714 | /* Swap the records for the two blocks around. */ |
65f34de5 | 715 | |
7fa55aef | 716 | unlink_block (a); |
717 | link_block (a, b->prev_bb); | |
718 | ||
65f34de5 | 719 | /* Now blocks A and B are contiguous. Merge them. */ |
c60fa3a7 | 720 | merge_blocks (a, b); |
65f34de5 | 721 | } |
722 | ||
723 | /* Blocks A and B are to be merged into a single block. B has no outgoing | |
724 | fallthru edge, so it can be moved after A without adding or modifying | |
725 | any jumps (aside from the jump from A to B). */ | |
726 | ||
e76f35e8 | 727 | static void |
4c9e08a4 | 728 | merge_blocks_move_successor_nojumps (basic_block a, basic_block b) |
65f34de5 | 729 | { |
c093ac49 | 730 | rtx_insn *barrier, *real_b_end; |
c86d86ff | 731 | rtx label; |
732 | rtx_jump_table_data *table; | |
65f34de5 | 733 | |
4f18499c | 734 | /* If we are partitioning hot/cold basic blocks, we don't want to |
735 | mess up unconditional or indirect jumps that cross between hot | |
a0c938f0 | 736 | and cold sections. |
737 | ||
1118aef7 | 738 | Basic block partitioning may result in some jumps that appear to |
a0c938f0 | 739 | be optimizable (or blocks that appear to be mergeable), but which really |
740 | must be left untouched (they are required to make it safely across | |
741 | partition boundaries). See the comments at the top of | |
1118aef7 | 742 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
743 | ||
1897b881 | 744 | if (BB_PARTITION (a) != BB_PARTITION (b)) |
4f18499c | 745 | return; |
746 | ||
5496dbfc | 747 | real_b_end = BB_END (b); |
65f34de5 | 748 | |
afff715a | 749 | /* If there is a jump table following block B temporarily add the jump table |
750 | to block B so that it will also be moved to the correct location. */ | |
5496dbfc | 751 | if (tablejump_p (BB_END (b), &label, &table) |
752 | && prev_active_insn (label) == BB_END (b)) | |
65f34de5 | 753 | { |
26bb3cb2 | 754 | BB_END (b) = table; |
65f34de5 | 755 | } |
756 | ||
757 | /* There had better have been a barrier there. Delete it. */ | |
5496dbfc | 758 | barrier = NEXT_INSN (BB_END (b)); |
6d7dc5b9 | 759 | if (barrier && BARRIER_P (barrier)) |
e4bf866d | 760 | delete_insn (barrier); |
65f34de5 | 761 | |
65f34de5 | 762 | |
763 | /* Scramble the insn chain. */ | |
5496dbfc | 764 | reorder_insns_nobb (BB_HEAD (b), BB_END (b), BB_END (a)); |
65f34de5 | 765 | |
f70d6641 | 766 | /* Restore the real end of b. */ |
26bb3cb2 | 767 | BB_END (b) = real_b_end; |
f70d6641 | 768 | |
450d042a | 769 | if (dump_file) |
770 | fprintf (dump_file, "Moved block %d after %d and merged.\n", | |
b3d6de89 | 771 | b->index, a->index); |
cd2e6f57 | 772 | |
773 | /* Now blocks A and B are contiguous. Merge them. */ | |
c60fa3a7 | 774 | merge_blocks (a, b); |
65f34de5 | 775 | } |
776 | ||
777 | /* Attempt to merge basic blocks that are potentially non-adjacent. | |
9d574a94 | 778 | Return NULL iff the attempt failed, otherwise return basic block |
779 | where cleanup_cfg should continue. Because the merging commonly | |
780 | moves basic block away or introduces another optimization | |
d01481af | 781 | possibility, return basic block just before B so cleanup_cfg don't |
9d574a94 | 782 | need to iterate. |
783 | ||
784 | It may be good idea to return basic block before C in the case | |
785 | C has been moved after B and originally appeared earlier in the | |
917bbcab | 786 | insn sequence, but we have no information available about the |
9d574a94 | 787 | relative ordering of these two. Hopefully it is not too common. */ |
788 | ||
789 | static basic_block | |
c60fa3a7 | 790 | merge_blocks_move (edge e, basic_block b, basic_block c, int mode) |
65f34de5 | 791 | { |
9d574a94 | 792 | basic_block next; |
65f34de5 | 793 | |
4f18499c | 794 | /* If we are partitioning hot/cold basic blocks, we don't want to |
795 | mess up unconditional or indirect jumps that cross between hot | |
a0c938f0 | 796 | and cold sections. |
797 | ||
1118aef7 | 798 | Basic block partitioning may result in some jumps that appear to |
a0c938f0 | 799 | be optimizable (or blocks that appear to be mergeable), but which really |
800 | must be left untouched (they are required to make it safely across | |
801 | partition boundaries). See the comments at the top of | |
1118aef7 | 802 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
803 | ||
1897b881 | 804 | if (BB_PARTITION (b) != BB_PARTITION (c)) |
4f18499c | 805 | return NULL; |
a0c938f0 | 806 | |
65f34de5 | 807 | /* If B has a fallthru edge to C, no need to move anything. */ |
808 | if (e->flags & EDGE_FALLTHRU) | |
809 | { | |
b3d6de89 | 810 | int b_index = b->index, c_index = c->index; |
79f958cb | 811 | |
812 | /* Protect the loop latches. */ | |
813 | if (current_loops && c->loop_father->latch == c) | |
814 | return NULL; | |
815 | ||
c60fa3a7 | 816 | merge_blocks (b, c); |
33dbe4d1 | 817 | update_forwarder_flag (b); |
65f34de5 | 818 | |
450d042a | 819 | if (dump_file) |
820 | fprintf (dump_file, "Merged %d and %d without moving.\n", | |
db34a109 | 821 | b_index, c_index); |
65f34de5 | 822 | |
34154e27 | 823 | return b->prev_bb == ENTRY_BLOCK_PTR_FOR_FN (cfun) ? b : b->prev_bb; |
65f34de5 | 824 | } |
5cc577b6 | 825 | |
65f34de5 | 826 | /* Otherwise we will need to move code around. Do that only if expensive |
827 | transformations are allowed. */ | |
828 | else if (mode & CLEANUP_EXPENSIVE) | |
829 | { | |
e76f35e8 | 830 | edge tmp_edge, b_fallthru_edge; |
831 | bool c_has_outgoing_fallthru; | |
832 | bool b_has_incoming_fallthru; | |
65f34de5 | 833 | |
834 | /* Avoid overactive code motion, as the forwarder blocks should be | |
a0c938f0 | 835 | eliminated by edge redirection instead. One exception might have |
65f34de5 | 836 | been if B is a forwarder block and C has no fallthru edge, but |
837 | that should be cleaned up by bb-reorder instead. */ | |
33dbe4d1 | 838 | if (FORWARDER_BLOCK_P (b) || FORWARDER_BLOCK_P (c)) |
9d574a94 | 839 | return NULL; |
65f34de5 | 840 | |
841 | /* We must make sure to not munge nesting of lexical blocks, | |
842 | and loop notes. This is done by squeezing out all the notes | |
843 | and leaving them there to lie. Not ideal, but functional. */ | |
844 | ||
7f58c05e | 845 | tmp_edge = find_fallthru_edge (c->succs); |
65f34de5 | 846 | c_has_outgoing_fallthru = (tmp_edge != NULL); |
65f34de5 | 847 | |
7f58c05e | 848 | tmp_edge = find_fallthru_edge (b->preds); |
65f34de5 | 849 | b_has_incoming_fallthru = (tmp_edge != NULL); |
e76f35e8 | 850 | b_fallthru_edge = tmp_edge; |
9d574a94 | 851 | next = b->prev_bb; |
a6a0ec1c | 852 | if (next == c) |
853 | next = next->prev_bb; | |
e76f35e8 | 854 | |
855 | /* Otherwise, we're going to try to move C after B. If C does | |
856 | not have an outgoing fallthru, then it can be moved | |
857 | immediately after B without introducing or modifying jumps. */ | |
858 | if (! c_has_outgoing_fallthru) | |
859 | { | |
860 | merge_blocks_move_successor_nojumps (b, c); | |
34154e27 | 861 | return next == ENTRY_BLOCK_PTR_FOR_FN (cfun) ? next->next_bb : next; |
e76f35e8 | 862 | } |
65f34de5 | 863 | |
864 | /* If B does not have an incoming fallthru, then it can be moved | |
865 | immediately before C without introducing or modifying jumps. | |
866 | C cannot be the first block, so we do not have to worry about | |
867 | accessing a non-existent block. */ | |
65f34de5 | 868 | |
e76f35e8 | 869 | if (b_has_incoming_fallthru) |
870 | { | |
0922c912 | 871 | basic_block bb; |
5cc577b6 | 872 | |
34154e27 | 873 | if (b_fallthru_edge->src == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
9d574a94 | 874 | return NULL; |
2a22a8e6 | 875 | bb = force_nonfallthru (b_fallthru_edge); |
876 | if (bb) | |
877 | notice_new_block (bb); | |
e76f35e8 | 878 | } |
5cc577b6 | 879 | |
e76f35e8 | 880 | merge_blocks_move_predecessor_nojumps (b, c); |
34154e27 | 881 | return next == ENTRY_BLOCK_PTR_FOR_FN (cfun) ? next->next_bb : next; |
65f34de5 | 882 | } |
5cc577b6 | 883 | |
63b616bf | 884 | return NULL; |
65f34de5 | 885 | } |
886 | \f | |
1d133110 | 887 | |
888 | /* Removes the memory attributes of MEM expression | |
889 | if they are not equal. */ | |
890 | ||
e5a23585 | 891 | static void |
1d133110 | 892 | merge_memattrs (rtx x, rtx y) |
893 | { | |
894 | int i; | |
895 | int j; | |
896 | enum rtx_code code; | |
897 | const char *fmt; | |
898 | ||
899 | if (x == y) | |
900 | return; | |
901 | if (x == 0 || y == 0) | |
902 | return; | |
903 | ||
904 | code = GET_CODE (x); | |
905 | ||
906 | if (code != GET_CODE (y)) | |
907 | return; | |
908 | ||
909 | if (GET_MODE (x) != GET_MODE (y)) | |
910 | return; | |
911 | ||
7e304b71 | 912 | if (code == MEM && !mem_attrs_eq_p (MEM_ATTRS (x), MEM_ATTRS (y))) |
1d133110 | 913 | { |
914 | if (! MEM_ATTRS (x)) | |
915 | MEM_ATTRS (y) = 0; | |
916 | else if (! MEM_ATTRS (y)) | |
917 | MEM_ATTRS (x) = 0; | |
a0c938f0 | 918 | else |
1d133110 | 919 | { |
5b2a69fa | 920 | HOST_WIDE_INT mem_size; |
1d133110 | 921 | |
922 | if (MEM_ALIAS_SET (x) != MEM_ALIAS_SET (y)) | |
923 | { | |
924 | set_mem_alias_set (x, 0); | |
925 | set_mem_alias_set (y, 0); | |
926 | } | |
a0c938f0 | 927 | |
1d133110 | 928 | if (! mem_expr_equal_p (MEM_EXPR (x), MEM_EXPR (y))) |
929 | { | |
930 | set_mem_expr (x, 0); | |
931 | set_mem_expr (y, 0); | |
da443c27 | 932 | clear_mem_offset (x); |
933 | clear_mem_offset (y); | |
1d133110 | 934 | } |
da443c27 | 935 | else if (MEM_OFFSET_KNOWN_P (x) != MEM_OFFSET_KNOWN_P (y) |
936 | || (MEM_OFFSET_KNOWN_P (x) | |
937 | && MEM_OFFSET (x) != MEM_OFFSET (y))) | |
1d133110 | 938 | { |
da443c27 | 939 | clear_mem_offset (x); |
940 | clear_mem_offset (y); | |
1d133110 | 941 | } |
a0c938f0 | 942 | |
5b2a69fa | 943 | if (MEM_SIZE_KNOWN_P (x) && MEM_SIZE_KNOWN_P (y)) |
944 | { | |
945 | mem_size = MAX (MEM_SIZE (x), MEM_SIZE (y)); | |
946 | set_mem_size (x, mem_size); | |
947 | set_mem_size (y, mem_size); | |
948 | } | |
1d133110 | 949 | else |
5b2a69fa | 950 | { |
951 | clear_mem_size (x); | |
952 | clear_mem_size (y); | |
953 | } | |
1d133110 | 954 | |
955 | set_mem_align (x, MIN (MEM_ALIGN (x), MEM_ALIGN (y))); | |
956 | set_mem_align (y, MEM_ALIGN (x)); | |
957 | } | |
958 | } | |
d8a2f839 | 959 | if (code == MEM) |
960 | { | |
961 | if (MEM_READONLY_P (x) != MEM_READONLY_P (y)) | |
962 | { | |
963 | MEM_READONLY_P (x) = 0; | |
964 | MEM_READONLY_P (y) = 0; | |
965 | } | |
966 | if (MEM_NOTRAP_P (x) != MEM_NOTRAP_P (y)) | |
967 | { | |
968 | MEM_NOTRAP_P (x) = 0; | |
969 | MEM_NOTRAP_P (y) = 0; | |
970 | } | |
971 | if (MEM_VOLATILE_P (x) != MEM_VOLATILE_P (y)) | |
972 | { | |
973 | MEM_VOLATILE_P (x) = 1; | |
974 | MEM_VOLATILE_P (y) = 1; | |
975 | } | |
976 | } | |
a0c938f0 | 977 | |
1d133110 | 978 | fmt = GET_RTX_FORMAT (code); |
979 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
980 | { | |
981 | switch (fmt[i]) | |
982 | { | |
983 | case 'E': | |
984 | /* Two vectors must have the same length. */ | |
985 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
986 | return; | |
987 | ||
988 | for (j = 0; j < XVECLEN (x, i); j++) | |
989 | merge_memattrs (XVECEXP (x, i, j), XVECEXP (y, i, j)); | |
990 | ||
991 | break; | |
992 | ||
993 | case 'e': | |
994 | merge_memattrs (XEXP (x, i), XEXP (y, i)); | |
995 | } | |
996 | } | |
997 | return; | |
998 | } | |
999 | ||
1000 | ||
764aef11 | 1001 | /* Checks if patterns P1 and P2 are equivalent, apart from the possibly |
1002 | different single sets S1 and S2. */ | |
1d133110 | 1003 | |
1004 | static bool | |
764aef11 | 1005 | equal_different_set_p (rtx p1, rtx s1, rtx p2, rtx s2) |
1006 | { | |
1007 | int i; | |
1008 | rtx e1, e2; | |
1009 | ||
1010 | if (p1 == s1 && p2 == s2) | |
1011 | return true; | |
1012 | ||
1013 | if (GET_CODE (p1) != PARALLEL || GET_CODE (p2) != PARALLEL) | |
1014 | return false; | |
1015 | ||
1016 | if (XVECLEN (p1, 0) != XVECLEN (p2, 0)) | |
1017 | return false; | |
1018 | ||
1019 | for (i = 0; i < XVECLEN (p1, 0); i++) | |
1020 | { | |
1021 | e1 = XVECEXP (p1, 0, i); | |
1022 | e2 = XVECEXP (p2, 0, i); | |
1023 | if (e1 == s1 && e2 == s2) | |
1024 | continue; | |
1025 | if (reload_completed | |
1026 | ? rtx_renumbered_equal_p (e1, e2) : rtx_equal_p (e1, e2)) | |
1027 | continue; | |
1028 | ||
5c6f6a61 | 1029 | return false; |
764aef11 | 1030 | } |
1031 | ||
1032 | return true; | |
1033 | } | |
1034 | ||
961843f3 | 1035 | |
1036 | /* NOTE1 is the REG_EQUAL note, if any, attached to an insn | |
1037 | that is a single_set with a SET_SRC of SRC1. Similarly | |
1038 | for NOTE2/SRC2. | |
1039 | ||
1040 | So effectively NOTE1/NOTE2 are an alternate form of | |
1041 | SRC1/SRC2 respectively. | |
1042 | ||
1043 | Return nonzero if SRC1 or NOTE1 has the same constant | |
1044 | integer value as SRC2 or NOTE2. Else return zero. */ | |
1045 | static int | |
1046 | values_equal_p (rtx note1, rtx note2, rtx src1, rtx src2) | |
1047 | { | |
1048 | if (note1 | |
1049 | && note2 | |
1050 | && CONST_INT_P (XEXP (note1, 0)) | |
1051 | && rtx_equal_p (XEXP (note1, 0), XEXP (note2, 0))) | |
1052 | return 1; | |
1053 | ||
1054 | if (!note1 | |
1055 | && !note2 | |
1056 | && CONST_INT_P (src1) | |
1057 | && CONST_INT_P (src2) | |
1058 | && rtx_equal_p (src1, src2)) | |
1059 | return 1; | |
1060 | ||
1061 | if (note1 | |
1062 | && CONST_INT_P (src2) | |
1063 | && rtx_equal_p (XEXP (note1, 0), src2)) | |
1064 | return 1; | |
1065 | ||
1066 | if (note2 | |
1067 | && CONST_INT_P (src1) | |
1068 | && rtx_equal_p (XEXP (note2, 0), src1)) | |
1069 | return 1; | |
1070 | ||
1071 | return 0; | |
1072 | } | |
1073 | ||
764aef11 | 1074 | /* Examine register notes on I1 and I2 and return: |
1075 | - dir_forward if I1 can be replaced by I2, or | |
1076 | - dir_backward if I2 can be replaced by I1, or | |
1077 | - dir_both if both are the case. */ | |
1078 | ||
1079 | static enum replace_direction | |
c093ac49 | 1080 | can_replace_by (rtx_insn *i1, rtx_insn *i2) |
764aef11 | 1081 | { |
1082 | rtx s1, s2, d1, d2, src1, src2, note1, note2; | |
1083 | bool c1, c2; | |
1084 | ||
1085 | /* Check for 2 sets. */ | |
1086 | s1 = single_set (i1); | |
1087 | s2 = single_set (i2); | |
1088 | if (s1 == NULL_RTX || s2 == NULL_RTX) | |
1089 | return dir_none; | |
1090 | ||
1091 | /* Check that the 2 sets set the same dest. */ | |
1092 | d1 = SET_DEST (s1); | |
1093 | d2 = SET_DEST (s2); | |
1094 | if (!(reload_completed | |
1095 | ? rtx_renumbered_equal_p (d1, d2) : rtx_equal_p (d1, d2))) | |
1096 | return dir_none; | |
1097 | ||
1098 | /* Find identical req_equiv or reg_equal note, which implies that the 2 sets | |
1099 | set dest to the same value. */ | |
1100 | note1 = find_reg_equal_equiv_note (i1); | |
1101 | note2 = find_reg_equal_equiv_note (i2); | |
961843f3 | 1102 | |
1103 | src1 = SET_SRC (s1); | |
1104 | src2 = SET_SRC (s2); | |
1105 | ||
1106 | if (!values_equal_p (note1, note2, src1, src2)) | |
764aef11 | 1107 | return dir_none; |
1108 | ||
1109 | if (!equal_different_set_p (PATTERN (i1), s1, PATTERN (i2), s2)) | |
1110 | return dir_none; | |
1111 | ||
1112 | /* Although the 2 sets set dest to the same value, we cannot replace | |
1113 | (set (dest) (const_int)) | |
1114 | by | |
1115 | (set (dest) (reg)) | |
1116 | because we don't know if the reg is live and has the same value at the | |
1117 | location of replacement. */ | |
764aef11 | 1118 | c1 = CONST_INT_P (src1); |
1119 | c2 = CONST_INT_P (src2); | |
1120 | if (c1 && c2) | |
1121 | return dir_both; | |
1122 | else if (c2) | |
1123 | return dir_forward; | |
1124 | else if (c1) | |
1125 | return dir_backward; | |
1126 | ||
1127 | return dir_none; | |
1128 | } | |
1129 | ||
1130 | /* Merges directions A and B. */ | |
1131 | ||
1132 | static enum replace_direction | |
1133 | merge_dir (enum replace_direction a, enum replace_direction b) | |
1134 | { | |
1135 | /* Implements the following table: | |
1136 | |bo fw bw no | |
1137 | ---+----------- | |
1138 | bo |bo fw bw no | |
1139 | fw |-- fw no no | |
1140 | bw |-- -- bw no | |
1141 | no |-- -- -- no. */ | |
1142 | ||
1143 | if (a == b) | |
1144 | return a; | |
1145 | ||
1146 | if (a == dir_both) | |
1147 | return b; | |
1148 | if (b == dir_both) | |
1149 | return a; | |
1150 | ||
1151 | return dir_none; | |
1152 | } | |
1153 | ||
1154 | /* Examine I1 and I2 and return: | |
1155 | - dir_forward if I1 can be replaced by I2, or | |
1156 | - dir_backward if I2 can be replaced by I1, or | |
1157 | - dir_both if both are the case. */ | |
1158 | ||
1159 | static enum replace_direction | |
c093ac49 | 1160 | old_insns_match_p (int mode ATTRIBUTE_UNUSED, rtx_insn *i1, rtx_insn *i2) |
1d133110 | 1161 | { |
1162 | rtx p1, p2; | |
1163 | ||
1164 | /* Verify that I1 and I2 are equivalent. */ | |
1165 | if (GET_CODE (i1) != GET_CODE (i2)) | |
764aef11 | 1166 | return dir_none; |
1d133110 | 1167 | |
616b875f | 1168 | /* __builtin_unreachable() may lead to empty blocks (ending with |
1169 | NOTE_INSN_BASIC_BLOCK). They may be crossjumped. */ | |
1170 | if (NOTE_INSN_BASIC_BLOCK_P (i1) && NOTE_INSN_BASIC_BLOCK_P (i2)) | |
764aef11 | 1171 | return dir_both; |
616b875f | 1172 | |
dfe00a8f | 1173 | /* ??? Do not allow cross-jumping between different stack levels. */ |
1174 | p1 = find_reg_note (i1, REG_ARGS_SIZE, NULL); | |
1175 | p2 = find_reg_note (i2, REG_ARGS_SIZE, NULL); | |
40125f1c | 1176 | if (p1 && p2) |
1177 | { | |
1178 | p1 = XEXP (p1, 0); | |
1179 | p2 = XEXP (p2, 0); | |
1180 | if (!rtx_equal_p (p1, p2)) | |
1181 | return dir_none; | |
1182 | ||
1183 | /* ??? Worse, this adjustment had better be constant lest we | |
1184 | have differing incoming stack levels. */ | |
1185 | if (!frame_pointer_needed | |
1186 | && find_args_size_adjust (i1) == HOST_WIDE_INT_MIN) | |
1187 | return dir_none; | |
1188 | } | |
1189 | else if (p1 || p2) | |
dfe00a8f | 1190 | return dir_none; |
1191 | ||
17d1c688 | 1192 | p1 = PATTERN (i1); |
1d133110 | 1193 | p2 = PATTERN (i2); |
1194 | ||
1195 | if (GET_CODE (p1) != GET_CODE (p2)) | |
764aef11 | 1196 | return dir_none; |
1d133110 | 1197 | |
1198 | /* If this is a CALL_INSN, compare register usage information. | |
1199 | If we don't check this on stack register machines, the two | |
1200 | CALL_INSNs might be merged leaving reg-stack.c with mismatching | |
1201 | numbers of stack registers in the same basic block. | |
1202 | If we don't check this on machines with delay slots, a delay slot may | |
1203 | be filled that clobbers a parameter expected by the subroutine. | |
1204 | ||
1205 | ??? We take the simple route for now and assume that if they're | |
84c471f5 | 1206 | equal, they were constructed identically. |
1d133110 | 1207 | |
84c471f5 | 1208 | Also check for identical exception regions. */ |
1209 | ||
1210 | if (CALL_P (i1)) | |
1211 | { | |
1212 | /* Ensure the same EH region. */ | |
1213 | rtx n1 = find_reg_note (i1, REG_EH_REGION, 0); | |
1214 | rtx n2 = find_reg_note (i2, REG_EH_REGION, 0); | |
1215 | ||
1216 | if (!n1 && n2) | |
764aef11 | 1217 | return dir_none; |
84c471f5 | 1218 | |
1219 | if (n1 && (!n2 || XEXP (n1, 0) != XEXP (n2, 0))) | |
764aef11 | 1220 | return dir_none; |
84c471f5 | 1221 | |
1222 | if (!rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1), | |
a0c938f0 | 1223 | CALL_INSN_FUNCTION_USAGE (i2)) |
84c471f5 | 1224 | || SIBLING_CALL_P (i1) != SIBLING_CALL_P (i2)) |
764aef11 | 1225 | return dir_none; |
09c97583 | 1226 | |
1227 | /* For address sanitizer, never crossjump __asan_report_* builtins, | |
1228 | otherwise errors might be reported on incorrect lines. */ | |
9e46467d | 1229 | if (flag_sanitize & SANITIZE_ADDRESS) |
09c97583 | 1230 | { |
1231 | rtx call = get_call_rtx_from (i1); | |
1232 | if (call && GET_CODE (XEXP (XEXP (call, 0), 0)) == SYMBOL_REF) | |
1233 | { | |
1234 | rtx symbol = XEXP (XEXP (call, 0), 0); | |
1235 | if (SYMBOL_REF_DECL (symbol) | |
1236 | && TREE_CODE (SYMBOL_REF_DECL (symbol)) == FUNCTION_DECL) | |
1237 | { | |
1238 | if ((DECL_BUILT_IN_CLASS (SYMBOL_REF_DECL (symbol)) | |
1239 | == BUILT_IN_NORMAL) | |
1240 | && DECL_FUNCTION_CODE (SYMBOL_REF_DECL (symbol)) | |
1241 | >= BUILT_IN_ASAN_REPORT_LOAD1 | |
1242 | && DECL_FUNCTION_CODE (SYMBOL_REF_DECL (symbol)) | |
4f86f720 | 1243 | <= BUILT_IN_ASAN_STOREN) |
09c97583 | 1244 | return dir_none; |
1245 | } | |
1246 | } | |
1247 | } | |
84c471f5 | 1248 | } |
1d133110 | 1249 | |
1250 | #ifdef STACK_REGS | |
1251 | /* If cross_jump_death_matters is not 0, the insn's mode | |
1252 | indicates whether or not the insn contains any stack-like | |
1253 | regs. */ | |
1254 | ||
1255 | if ((mode & CLEANUP_POST_REGSTACK) && stack_regs_mentioned (i1)) | |
1256 | { | |
1257 | /* If register stack conversion has already been done, then | |
a0c938f0 | 1258 | death notes must also be compared before it is certain that |
1259 | the two instruction streams match. */ | |
1d133110 | 1260 | |
1261 | rtx note; | |
1262 | HARD_REG_SET i1_regset, i2_regset; | |
1263 | ||
1264 | CLEAR_HARD_REG_SET (i1_regset); | |
1265 | CLEAR_HARD_REG_SET (i2_regset); | |
1266 | ||
1267 | for (note = REG_NOTES (i1); note; note = XEXP (note, 1)) | |
1268 | if (REG_NOTE_KIND (note) == REG_DEAD && STACK_REG_P (XEXP (note, 0))) | |
1269 | SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0))); | |
1270 | ||
1271 | for (note = REG_NOTES (i2); note; note = XEXP (note, 1)) | |
1272 | if (REG_NOTE_KIND (note) == REG_DEAD && STACK_REG_P (XEXP (note, 0))) | |
1273 | SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0))); | |
1274 | ||
ddc556d1 | 1275 | if (!hard_reg_set_equal_p (i1_regset, i2_regset)) |
764aef11 | 1276 | return dir_none; |
1d133110 | 1277 | } |
1278 | #endif | |
1279 | ||
1280 | if (reload_completed | |
1281 | ? rtx_renumbered_equal_p (p1, p2) : rtx_equal_p (p1, p2)) | |
764aef11 | 1282 | return dir_both; |
1d133110 | 1283 | |
764aef11 | 1284 | return can_replace_by (i1, i2); |
1d133110 | 1285 | } |
1286 | \f | |
84c471f5 | 1287 | /* When comparing insns I1 and I2 in flow_find_cross_jump or |
1288 | flow_find_head_matching_sequence, ensure the notes match. */ | |
1289 | ||
1290 | static void | |
c093ac49 | 1291 | merge_notes (rtx_insn *i1, rtx_insn *i2) |
84c471f5 | 1292 | { |
1293 | /* If the merged insns have different REG_EQUAL notes, then | |
1294 | remove them. */ | |
1295 | rtx equiv1 = find_reg_equal_equiv_note (i1); | |
1296 | rtx equiv2 = find_reg_equal_equiv_note (i2); | |
1297 | ||
1298 | if (equiv1 && !equiv2) | |
1299 | remove_note (i1, equiv1); | |
1300 | else if (!equiv1 && equiv2) | |
1301 | remove_note (i2, equiv2); | |
1302 | else if (equiv1 && equiv2 | |
1303 | && !rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0))) | |
1304 | { | |
1305 | remove_note (i1, equiv1); | |
1306 | remove_note (i2, equiv2); | |
1307 | } | |
1308 | } | |
1309 | ||
4ef44dfa | 1310 | /* Walks from I1 in BB1 backward till the next non-debug insn, and returns the |
1311 | resulting insn in I1, and the corresponding bb in BB1. At the head of a | |
1312 | bb, if there is a predecessor bb that reaches this bb via fallthru, and | |
1313 | FOLLOW_FALLTHRU, walks further in the predecessor bb and registers this in | |
1314 | DID_FALLTHRU. Otherwise, stops at the head of the bb. */ | |
1315 | ||
1316 | static void | |
c093ac49 | 1317 | walk_to_nondebug_insn (rtx_insn **i1, basic_block *bb1, bool follow_fallthru, |
4ef44dfa | 1318 | bool *did_fallthru) |
1319 | { | |
1320 | edge fallthru; | |
1321 | ||
1322 | *did_fallthru = false; | |
1323 | ||
1324 | /* Ignore notes. */ | |
1325 | while (!NONDEBUG_INSN_P (*i1)) | |
1326 | { | |
1327 | if (*i1 != BB_HEAD (*bb1)) | |
1328 | { | |
1329 | *i1 = PREV_INSN (*i1); | |
1330 | continue; | |
1331 | } | |
1332 | ||
1333 | if (!follow_fallthru) | |
1334 | return; | |
1335 | ||
1336 | fallthru = find_fallthru_edge ((*bb1)->preds); | |
34154e27 | 1337 | if (!fallthru || fallthru->src == ENTRY_BLOCK_PTR_FOR_FN (cfun) |
4ef44dfa | 1338 | || !single_succ_p (fallthru->src)) |
1339 | return; | |
1340 | ||
1341 | *bb1 = fallthru->src; | |
1342 | *i1 = BB_END (*bb1); | |
1343 | *did_fallthru = true; | |
1344 | } | |
1345 | } | |
1346 | ||
1d133110 | 1347 | /* Look through the insns at the end of BB1 and BB2 and find the longest |
764aef11 | 1348 | sequence that are either equivalent, or allow forward or backward |
1349 | replacement. Store the first insns for that sequence in *F1 and *F2 and | |
1350 | return the sequence length. | |
1351 | ||
1352 | DIR_P indicates the allowed replacement direction on function entry, and | |
1353 | the actual replacement direction on function exit. If NULL, only equivalent | |
1354 | sequences are allowed. | |
1d133110 | 1355 | |
1356 | To simplify callers of this function, if the blocks match exactly, | |
1357 | store the head of the blocks in *F1 and *F2. */ | |
1358 | ||
84c471f5 | 1359 | int |
c093ac49 | 1360 | flow_find_cross_jump (basic_block bb1, basic_block bb2, rtx_insn **f1, |
1361 | rtx_insn **f2, enum replace_direction *dir_p) | |
1d133110 | 1362 | { |
c093ac49 | 1363 | rtx_insn *i1, *i2, *last1, *last2, *afterlast1, *afterlast2; |
1d133110 | 1364 | int ninsns = 0; |
764aef11 | 1365 | enum replace_direction dir, last_dir, afterlast_dir; |
4ef44dfa | 1366 | bool follow_fallthru, did_fallthru; |
764aef11 | 1367 | |
1368 | if (dir_p) | |
1369 | dir = *dir_p; | |
1370 | else | |
1371 | dir = dir_both; | |
1372 | afterlast_dir = dir; | |
1373 | last_dir = afterlast_dir; | |
1d133110 | 1374 | |
1375 | /* Skip simple jumps at the end of the blocks. Complex jumps still | |
1376 | need to be compared for equivalence, which we'll do below. */ | |
1377 | ||
1378 | i1 = BB_END (bb1); | |
c093ac49 | 1379 | last1 = afterlast1 = last2 = afterlast2 = NULL; |
1d133110 | 1380 | if (onlyjump_p (i1) |
1381 | || (returnjump_p (i1) && !side_effects_p (PATTERN (i1)))) | |
1382 | { | |
1383 | last1 = i1; | |
1384 | i1 = PREV_INSN (i1); | |
1385 | } | |
1386 | ||
1387 | i2 = BB_END (bb2); | |
1388 | if (onlyjump_p (i2) | |
1389 | || (returnjump_p (i2) && !side_effects_p (PATTERN (i2)))) | |
1390 | { | |
1391 | last2 = i2; | |
177a616b | 1392 | /* Count everything except for unconditional jump as insn. |
1393 | Don't count any jumps if dir_p is NULL. */ | |
1394 | if (!simplejump_p (i2) && !returnjump_p (i2) && last1 && dir_p) | |
1d133110 | 1395 | ninsns++; |
1396 | i2 = PREV_INSN (i2); | |
1397 | } | |
1398 | ||
1399 | while (true) | |
1400 | { | |
4ef44dfa | 1401 | /* In the following example, we can replace all jumps to C by jumps to A. |
1402 | ||
1403 | This removes 4 duplicate insns. | |
1404 | [bb A] insn1 [bb C] insn1 | |
1405 | insn2 insn2 | |
1406 | [bb B] insn3 insn3 | |
1407 | insn4 insn4 | |
1408 | jump_insn jump_insn | |
1409 | ||
1410 | We could also replace all jumps to A by jumps to C, but that leaves B | |
1411 | alive, and removes only 2 duplicate insns. In a subsequent crossjump | |
1412 | step, all jumps to B would be replaced with jumps to the middle of C, | |
1413 | achieving the same result with more effort. | |
1414 | So we allow only the first possibility, which means that we don't allow | |
1415 | fallthru in the block that's being replaced. */ | |
1416 | ||
1417 | follow_fallthru = dir_p && dir != dir_forward; | |
1418 | walk_to_nondebug_insn (&i1, &bb1, follow_fallthru, &did_fallthru); | |
1419 | if (did_fallthru) | |
1420 | dir = dir_backward; | |
1421 | ||
1422 | follow_fallthru = dir_p && dir != dir_backward; | |
1423 | walk_to_nondebug_insn (&i2, &bb2, follow_fallthru, &did_fallthru); | |
1424 | if (did_fallthru) | |
1425 | dir = dir_forward; | |
1d133110 | 1426 | |
1427 | if (i1 == BB_HEAD (bb1) || i2 == BB_HEAD (bb2)) | |
1428 | break; | |
1429 | ||
764aef11 | 1430 | dir = merge_dir (dir, old_insns_match_p (0, i1, i2)); |
1431 | if (dir == dir_none || (!dir_p && dir != dir_both)) | |
1d133110 | 1432 | break; |
1433 | ||
1434 | merge_memattrs (i1, i2); | |
1435 | ||
1436 | /* Don't begin a cross-jump with a NOTE insn. */ | |
1437 | if (INSN_P (i1)) | |
1438 | { | |
84c471f5 | 1439 | merge_notes (i1, i2); |
1d133110 | 1440 | |
1441 | afterlast1 = last1, afterlast2 = last2; | |
1442 | last1 = i1, last2 = i2; | |
764aef11 | 1443 | afterlast_dir = last_dir; |
1444 | last_dir = dir; | |
177a616b | 1445 | if (active_insn_p (i1)) |
e1ebb662 | 1446 | ninsns++; |
1d133110 | 1447 | } |
1448 | ||
1449 | i1 = PREV_INSN (i1); | |
1450 | i2 = PREV_INSN (i2); | |
1451 | } | |
1452 | ||
1d133110 | 1453 | /* Don't allow the insn after a compare to be shared by |
1454 | cross-jumping unless the compare is also shared. */ | |
693c9f42 | 1455 | if (HAVE_cc0 && ninsns && reg_mentioned_p (cc0_rtx, last1) |
1456 | && ! sets_cc0_p (last1)) | |
764aef11 | 1457 | last1 = afterlast1, last2 = afterlast2, last_dir = afterlast_dir, ninsns--; |
1d133110 | 1458 | |
1459 | /* Include preceding notes and labels in the cross-jump. One, | |
1460 | this may bring us to the head of the blocks as requested above. | |
1461 | Two, it keeps line number notes as matched as may be. */ | |
1462 | if (ninsns) | |
1463 | { | |
4ef44dfa | 1464 | bb1 = BLOCK_FOR_INSN (last1); |
9845d120 | 1465 | while (last1 != BB_HEAD (bb1) && !NONDEBUG_INSN_P (PREV_INSN (last1))) |
1d133110 | 1466 | last1 = PREV_INSN (last1); |
1467 | ||
1468 | if (last1 != BB_HEAD (bb1) && LABEL_P (PREV_INSN (last1))) | |
1469 | last1 = PREV_INSN (last1); | |
1470 | ||
4ef44dfa | 1471 | bb2 = BLOCK_FOR_INSN (last2); |
9845d120 | 1472 | while (last2 != BB_HEAD (bb2) && !NONDEBUG_INSN_P (PREV_INSN (last2))) |
1d133110 | 1473 | last2 = PREV_INSN (last2); |
1474 | ||
1475 | if (last2 != BB_HEAD (bb2) && LABEL_P (PREV_INSN (last2))) | |
1476 | last2 = PREV_INSN (last2); | |
1477 | ||
1478 | *f1 = last1; | |
1479 | *f2 = last2; | |
1480 | } | |
1481 | ||
764aef11 | 1482 | if (dir_p) |
1483 | *dir_p = last_dir; | |
1d133110 | 1484 | return ninsns; |
1485 | } | |
1486 | ||
84c471f5 | 1487 | /* Like flow_find_cross_jump, except start looking for a matching sequence from |
1488 | the head of the two blocks. Do not include jumps at the end. | |
1489 | If STOP_AFTER is nonzero, stop after finding that many matching | |
964c7827 | 1490 | instructions. If STOP_AFTER is zero, count all INSN_P insns, if it is |
1491 | non-zero, only count active insns. */ | |
84c471f5 | 1492 | |
1493 | int | |
c093ac49 | 1494 | flow_find_head_matching_sequence (basic_block bb1, basic_block bb2, rtx_insn **f1, |
1495 | rtx_insn **f2, int stop_after) | |
84c471f5 | 1496 | { |
c093ac49 | 1497 | rtx_insn *i1, *i2, *last1, *last2, *beforelast1, *beforelast2; |
84c471f5 | 1498 | int ninsns = 0; |
1499 | edge e; | |
1500 | edge_iterator ei; | |
1501 | int nehedges1 = 0, nehedges2 = 0; | |
1502 | ||
1503 | FOR_EACH_EDGE (e, ei, bb1->succs) | |
1504 | if (e->flags & EDGE_EH) | |
1505 | nehedges1++; | |
1506 | FOR_EACH_EDGE (e, ei, bb2->succs) | |
1507 | if (e->flags & EDGE_EH) | |
1508 | nehedges2++; | |
1509 | ||
1510 | i1 = BB_HEAD (bb1); | |
1511 | i2 = BB_HEAD (bb2); | |
c093ac49 | 1512 | last1 = beforelast1 = last2 = beforelast2 = NULL; |
84c471f5 | 1513 | |
1514 | while (true) | |
1515 | { | |
bc6adae4 | 1516 | /* Ignore notes, except NOTE_INSN_EPILOGUE_BEG. */ |
84c471f5 | 1517 | while (!NONDEBUG_INSN_P (i1) && i1 != BB_END (bb1)) |
bc6adae4 | 1518 | { |
1519 | if (NOTE_P (i1) && NOTE_KIND (i1) == NOTE_INSN_EPILOGUE_BEG) | |
1520 | break; | |
1521 | i1 = NEXT_INSN (i1); | |
1522 | } | |
84c471f5 | 1523 | |
1524 | while (!NONDEBUG_INSN_P (i2) && i2 != BB_END (bb2)) | |
bc6adae4 | 1525 | { |
1526 | if (NOTE_P (i2) && NOTE_KIND (i2) == NOTE_INSN_EPILOGUE_BEG) | |
1527 | break; | |
1528 | i2 = NEXT_INSN (i2); | |
1529 | } | |
84c471f5 | 1530 | |
2b93e478 | 1531 | if ((i1 == BB_END (bb1) && !NONDEBUG_INSN_P (i1)) |
1532 | || (i2 == BB_END (bb2) && !NONDEBUG_INSN_P (i2))) | |
1533 | break; | |
1534 | ||
84c471f5 | 1535 | if (NOTE_P (i1) || NOTE_P (i2) |
1536 | || JUMP_P (i1) || JUMP_P (i2)) | |
1537 | break; | |
1538 | ||
1539 | /* A sanity check to make sure we're not merging insns with different | |
1540 | effects on EH. If only one of them ends a basic block, it shouldn't | |
1541 | have an EH edge; if both end a basic block, there should be the same | |
1542 | number of EH edges. */ | |
1543 | if ((i1 == BB_END (bb1) && i2 != BB_END (bb2) | |
1544 | && nehedges1 > 0) | |
1545 | || (i2 == BB_END (bb2) && i1 != BB_END (bb1) | |
1546 | && nehedges2 > 0) | |
1547 | || (i1 == BB_END (bb1) && i2 == BB_END (bb2) | |
1548 | && nehedges1 != nehedges2)) | |
1549 | break; | |
1550 | ||
764aef11 | 1551 | if (old_insns_match_p (0, i1, i2) != dir_both) |
84c471f5 | 1552 | break; |
1553 | ||
1554 | merge_memattrs (i1, i2); | |
1555 | ||
1556 | /* Don't begin a cross-jump with a NOTE insn. */ | |
1557 | if (INSN_P (i1)) | |
1558 | { | |
1559 | merge_notes (i1, i2); | |
1560 | ||
1561 | beforelast1 = last1, beforelast2 = last2; | |
1562 | last1 = i1, last2 = i2; | |
964c7827 | 1563 | if (!stop_after || active_insn_p (i1)) |
177a616b | 1564 | ninsns++; |
84c471f5 | 1565 | } |
1566 | ||
1567 | if (i1 == BB_END (bb1) || i2 == BB_END (bb2) | |
1568 | || (stop_after > 0 && ninsns == stop_after)) | |
1569 | break; | |
1570 | ||
1571 | i1 = NEXT_INSN (i1); | |
1572 | i2 = NEXT_INSN (i2); | |
1573 | } | |
1574 | ||
84c471f5 | 1575 | /* Don't allow a compare to be shared by cross-jumping unless the insn |
1576 | after the compare is also shared. */ | |
693c9f42 | 1577 | if (HAVE_cc0 && ninsns && reg_mentioned_p (cc0_rtx, last1) |
1578 | && sets_cc0_p (last1)) | |
84c471f5 | 1579 | last1 = beforelast1, last2 = beforelast2, ninsns--; |
84c471f5 | 1580 | |
1581 | if (ninsns) | |
1582 | { | |
1583 | *f1 = last1; | |
1584 | *f2 = last2; | |
1585 | } | |
1586 | ||
1587 | return ninsns; | |
1588 | } | |
1589 | ||
1d133110 | 1590 | /* Return true iff outgoing edges of BB1 and BB2 match, together with |
1591 | the branch instruction. This means that if we commonize the control | |
1592 | flow before end of the basic block, the semantic remains unchanged. | |
65f34de5 | 1593 | |
1594 | We may assume that there exists one edge with a common destination. */ | |
1595 | ||
1596 | static bool | |
1d133110 | 1597 | outgoing_edges_match (int mode, basic_block bb1, basic_block bb2) |
65f34de5 | 1598 | { |
ba38e12b | 1599 | int nehedges1 = 0, nehedges2 = 0; |
1600 | edge fallthru1 = 0, fallthru2 = 0; | |
1601 | edge e1, e2; | |
cd665a06 | 1602 | edge_iterator ei; |
ba38e12b | 1603 | |
efee62d1 | 1604 | /* If we performed shrink-wrapping, edges to the exit block can |
1f021f97 | 1605 | only be distinguished for JUMP_INSNs. The two paths may differ in |
1606 | whether they went through the prologue. Sibcalls are fine, we know | |
1607 | that we either didn't need or inserted an epilogue before them. */ | |
1608 | if (crtl->shrink_wrapped | |
34154e27 | 1609 | && single_succ_p (bb1) |
1610 | && single_succ (bb1) == EXIT_BLOCK_PTR_FOR_FN (cfun) | |
1f021f97 | 1611 | && !JUMP_P (BB_END (bb1)) |
1612 | && !(CALL_P (BB_END (bb1)) && SIBLING_CALL_P (BB_END (bb1)))) | |
1613 | return false; | |
1614 | ||
337b10d0 | 1615 | /* If BB1 has only one successor, we may be looking at either an |
1616 | unconditional jump, or a fake edge to exit. */ | |
ea091dfd | 1617 | if (single_succ_p (bb1) |
1618 | && (single_succ_edge (bb1)->flags & (EDGE_COMPLEX | EDGE_FAKE)) == 0 | |
6d7dc5b9 | 1619 | && (!JUMP_P (BB_END (bb1)) || simplejump_p (BB_END (bb1)))) |
ea091dfd | 1620 | return (single_succ_p (bb2) |
1621 | && (single_succ_edge (bb2)->flags | |
1622 | & (EDGE_COMPLEX | EDGE_FAKE)) == 0 | |
6d7dc5b9 | 1623 | && (!JUMP_P (BB_END (bb2)) || simplejump_p (BB_END (bb2)))); |
65f34de5 | 1624 | |
1625 | /* Match conditional jumps - this may get tricky when fallthru and branch | |
1626 | edges are crossed. */ | |
cd665a06 | 1627 | if (EDGE_COUNT (bb1->succs) == 2 |
5496dbfc | 1628 | && any_condjump_p (BB_END (bb1)) |
1629 | && onlyjump_p (BB_END (bb1))) | |
65f34de5 | 1630 | { |
1d133110 | 1631 | edge b1, f1, b2, f2; |
1632 | bool reverse, match; | |
1633 | rtx set1, set2, cond1, cond2; | |
1634 | enum rtx_code code1, code2; | |
1635 | ||
cd665a06 | 1636 | if (EDGE_COUNT (bb2->succs) != 2 |
5496dbfc | 1637 | || !any_condjump_p (BB_END (bb2)) |
1638 | || !onlyjump_p (BB_END (bb2))) | |
26fb1781 | 1639 | return false; |
1d133110 | 1640 | |
1641 | b1 = BRANCH_EDGE (bb1); | |
1642 | b2 = BRANCH_EDGE (bb2); | |
1643 | f1 = FALLTHRU_EDGE (bb1); | |
1644 | f2 = FALLTHRU_EDGE (bb2); | |
1645 | ||
1646 | /* Get around possible forwarders on fallthru edges. Other cases | |
a0c938f0 | 1647 | should be optimized out already. */ |
1d133110 | 1648 | if (FORWARDER_BLOCK_P (f1->dest)) |
1649 | f1 = single_succ_edge (f1->dest); | |
1650 | ||
1651 | if (FORWARDER_BLOCK_P (f2->dest)) | |
1652 | f2 = single_succ_edge (f2->dest); | |
1653 | ||
1654 | /* To simplify use of this function, return false if there are | |
1655 | unneeded forwarder blocks. These will get eliminated later | |
1656 | during cleanup_cfg. */ | |
1657 | if (FORWARDER_BLOCK_P (f1->dest) | |
1658 | || FORWARDER_BLOCK_P (f2->dest) | |
1659 | || FORWARDER_BLOCK_P (b1->dest) | |
1660 | || FORWARDER_BLOCK_P (b2->dest)) | |
1661 | return false; | |
1662 | ||
1663 | if (f1->dest == f2->dest && b1->dest == b2->dest) | |
1664 | reverse = false; | |
1665 | else if (f1->dest == b2->dest && b1->dest == f2->dest) | |
1666 | reverse = true; | |
1667 | else | |
1668 | return false; | |
1669 | ||
1670 | set1 = pc_set (BB_END (bb1)); | |
1671 | set2 = pc_set (BB_END (bb2)); | |
1672 | if ((XEXP (SET_SRC (set1), 1) == pc_rtx) | |
1673 | != (XEXP (SET_SRC (set2), 1) == pc_rtx)) | |
1674 | reverse = !reverse; | |
1675 | ||
1676 | cond1 = XEXP (SET_SRC (set1), 0); | |
1677 | cond2 = XEXP (SET_SRC (set2), 0); | |
1678 | code1 = GET_CODE (cond1); | |
1679 | if (reverse) | |
1680 | code2 = reversed_comparison_code (cond2, BB_END (bb2)); | |
1681 | else | |
1682 | code2 = GET_CODE (cond2); | |
1683 | ||
1684 | if (code2 == UNKNOWN) | |
1685 | return false; | |
1686 | ||
1687 | /* Verify codes and operands match. */ | |
1688 | match = ((code1 == code2 | |
1689 | && rtx_renumbered_equal_p (XEXP (cond1, 0), XEXP (cond2, 0)) | |
1690 | && rtx_renumbered_equal_p (XEXP (cond1, 1), XEXP (cond2, 1))) | |
1691 | || (code1 == swap_condition (code2) | |
1692 | && rtx_renumbered_equal_p (XEXP (cond1, 1), | |
1693 | XEXP (cond2, 0)) | |
1694 | && rtx_renumbered_equal_p (XEXP (cond1, 0), | |
1695 | XEXP (cond2, 1)))); | |
1696 | ||
1697 | /* If we return true, we will join the blocks. Which means that | |
1698 | we will only have one branch prediction bit to work with. Thus | |
1699 | we require the existing branches to have probabilities that are | |
1700 | roughly similar. */ | |
1701 | if (match | |
0bfd8d5c | 1702 | && optimize_bb_for_speed_p (bb1) |
1703 | && optimize_bb_for_speed_p (bb2)) | |
1d133110 | 1704 | { |
1705 | int prob2; | |
1706 | ||
1707 | if (b1->dest == b2->dest) | |
1708 | prob2 = b2->probability; | |
1709 | else | |
1710 | /* Do not use f2 probability as f2 may be forwarded. */ | |
1711 | prob2 = REG_BR_PROB_BASE - b2->probability; | |
1712 | ||
1713 | /* Fail if the difference in probabilities is greater than 50%. | |
1714 | This rules out two well-predicted branches with opposite | |
1715 | outcomes. */ | |
1716 | if (abs (b1->probability - prob2) > REG_BR_PROB_BASE / 2) | |
1717 | { | |
1718 | if (dump_file) | |
1719 | fprintf (dump_file, | |
1720 | "Outcomes of branch in bb %i and %i differ too much (%i %i)\n", | |
1721 | bb1->index, bb2->index, b1->probability, prob2); | |
1722 | ||
1723 | return false; | |
1724 | } | |
1725 | } | |
1726 | ||
1727 | if (dump_file && match) | |
1728 | fprintf (dump_file, "Conditionals in bb %i and %i match.\n", | |
1729 | bb1->index, bb2->index); | |
1730 | ||
1731 | return match; | |
65f34de5 | 1732 | } |
1733 | ||
edc2a478 | 1734 | /* Generic case - we are seeing a computed jump, table jump or trapping |
ba38e12b | 1735 | instruction. */ |
1736 | ||
f2756aab | 1737 | /* Check whether there are tablejumps in the end of BB1 and BB2. |
1738 | Return true if they are identical. */ | |
1739 | { | |
1740 | rtx label1, label2; | |
c86d86ff | 1741 | rtx_jump_table_data *table1, *table2; |
f2756aab | 1742 | |
5496dbfc | 1743 | if (tablejump_p (BB_END (bb1), &label1, &table1) |
1744 | && tablejump_p (BB_END (bb2), &label2, &table2) | |
f2756aab | 1745 | && GET_CODE (PATTERN (table1)) == GET_CODE (PATTERN (table2))) |
1746 | { | |
1747 | /* The labels should never be the same rtx. If they really are same | |
1748 | the jump tables are same too. So disable crossjumping of blocks BB1 | |
1749 | and BB2 because when deleting the common insns in the end of BB1 | |
4ee9c684 | 1750 | by delete_basic_block () the jump table would be deleted too. */ |
cda612f5 | 1751 | /* If LABEL2 is referenced in BB1->END do not do anything |
f2756aab | 1752 | because we would loose information when replacing |
1753 | LABEL1 by LABEL2 and then LABEL2 by LABEL1 in BB1->END. */ | |
5496dbfc | 1754 | if (label1 != label2 && !rtx_referenced_p (label2, BB_END (bb1))) |
f2756aab | 1755 | { |
1756 | /* Set IDENTICAL to true when the tables are identical. */ | |
1757 | bool identical = false; | |
1758 | rtx p1, p2; | |
1759 | ||
1760 | p1 = PATTERN (table1); | |
1761 | p2 = PATTERN (table2); | |
1762 | if (GET_CODE (p1) == ADDR_VEC && rtx_equal_p (p1, p2)) | |
1763 | { | |
1764 | identical = true; | |
1765 | } | |
1766 | else if (GET_CODE (p1) == ADDR_DIFF_VEC | |
1767 | && (XVECLEN (p1, 1) == XVECLEN (p2, 1)) | |
1768 | && rtx_equal_p (XEXP (p1, 2), XEXP (p2, 2)) | |
1769 | && rtx_equal_p (XEXP (p1, 3), XEXP (p2, 3))) | |
1770 | { | |
1771 | int i; | |
1772 | ||
1773 | identical = true; | |
1774 | for (i = XVECLEN (p1, 1) - 1; i >= 0 && identical; i--) | |
1775 | if (!rtx_equal_p (XVECEXP (p1, 1, i), XVECEXP (p2, 1, i))) | |
1776 | identical = false; | |
1777 | } | |
1778 | ||
1d133110 | 1779 | if (identical) |
f2756aab | 1780 | { |
f2756aab | 1781 | bool match; |
1782 | ||
1d133110 | 1783 | /* Temporarily replace references to LABEL1 with LABEL2 |
f2756aab | 1784 | in BB1->END so that we could compare the instructions. */ |
956816a2 | 1785 | replace_label_in_insn (BB_END (bb1), label1, label2, false); |
f2756aab | 1786 | |
764aef11 | 1787 | match = (old_insns_match_p (mode, BB_END (bb1), BB_END (bb2)) |
1788 | == dir_both); | |
450d042a | 1789 | if (dump_file && match) |
1790 | fprintf (dump_file, | |
f2756aab | 1791 | "Tablejumps in bb %i and %i match.\n", |
1792 | bb1->index, bb2->index); | |
1793 | ||
1d133110 | 1794 | /* Set the original label in BB1->END because when deleting |
1795 | a block whose end is a tablejump, the tablejump referenced | |
1796 | from the instruction is deleted too. */ | |
956816a2 | 1797 | replace_label_in_insn (BB_END (bb1), label2, label1, false); |
1d133110 | 1798 | |
f2756aab | 1799 | return match; |
1800 | } | |
1801 | } | |
1802 | return false; | |
1803 | } | |
1804 | } | |
f2756aab | 1805 | |
a7920b67 | 1806 | /* Find the last non-debug non-note instruction in each bb, except |
1807 | stop when we see the NOTE_INSN_BASIC_BLOCK, as old_insns_match_p | |
1808 | handles that case specially. old_insns_match_p does not handle | |
1809 | other types of instruction notes. */ | |
c093ac49 | 1810 | rtx_insn *last1 = BB_END (bb1); |
1811 | rtx_insn *last2 = BB_END (bb2); | |
a7920b67 | 1812 | while (!NOTE_INSN_BASIC_BLOCK_P (last1) && |
1813 | (DEBUG_INSN_P (last1) || NOTE_P (last1))) | |
1814 | last1 = PREV_INSN (last1); | |
1815 | while (!NOTE_INSN_BASIC_BLOCK_P (last2) && | |
1816 | (DEBUG_INSN_P (last2) || NOTE_P (last2))) | |
1817 | last2 = PREV_INSN (last2); | |
1818 | gcc_assert (last1 && last2); | |
1819 | ||
ba38e12b | 1820 | /* First ensure that the instructions match. There may be many outgoing |
f2756aab | 1821 | edges so this test is generally cheaper. */ |
f73960eb | 1822 | if (old_insns_match_p (mode, last1, last2) != dir_both) |
ba38e12b | 1823 | return false; |
1824 | ||
1825 | /* Search the outgoing edges, ensure that the counts do match, find possible | |
1826 | fallthru and exception handling edges since these needs more | |
1827 | validation. */ | |
cd665a06 | 1828 | if (EDGE_COUNT (bb1->succs) != EDGE_COUNT (bb2->succs)) |
1829 | return false; | |
1830 | ||
f73960eb | 1831 | bool nonfakeedges = false; |
cd665a06 | 1832 | FOR_EACH_EDGE (e1, ei, bb1->succs) |
ba38e12b | 1833 | { |
cd665a06 | 1834 | e2 = EDGE_SUCC (bb2, ei.index); |
a0c938f0 | 1835 | |
f73960eb | 1836 | if ((e1->flags & EDGE_FAKE) == 0) |
1837 | nonfakeedges = true; | |
1838 | ||
ba38e12b | 1839 | if (e1->flags & EDGE_EH) |
1840 | nehedges1++; | |
5cc577b6 | 1841 | |
ba38e12b | 1842 | if (e2->flags & EDGE_EH) |
1843 | nehedges2++; | |
5cc577b6 | 1844 | |
ba38e12b | 1845 | if (e1->flags & EDGE_FALLTHRU) |
1846 | fallthru1 = e1; | |
1847 | if (e2->flags & EDGE_FALLTHRU) | |
1848 | fallthru2 = e2; | |
1849 | } | |
5cc577b6 | 1850 | |
ba38e12b | 1851 | /* If number of edges of various types does not match, fail. */ |
cd665a06 | 1852 | if (nehedges1 != nehedges2 |
5cc577b6 | 1853 | || (fallthru1 != 0) != (fallthru2 != 0)) |
ba38e12b | 1854 | return false; |
1855 | ||
f73960eb | 1856 | /* If !ACCUMULATE_OUTGOING_ARGS, bb1 (and bb2) have no successors |
1857 | and the last real insn doesn't have REG_ARGS_SIZE note, don't | |
1858 | attempt to optimize, as the two basic blocks might have different | |
1859 | REG_ARGS_SIZE depths. For noreturn calls and unconditional | |
1860 | traps there should be REG_ARG_SIZE notes, they could be missing | |
1861 | for __builtin_unreachable () uses though. */ | |
1862 | if (!nonfakeedges | |
1863 | && !ACCUMULATE_OUTGOING_ARGS | |
1864 | && (!INSN_P (last1) | |
1865 | || !find_reg_note (last1, REG_ARGS_SIZE, NULL))) | |
1866 | return false; | |
1867 | ||
ba38e12b | 1868 | /* fallthru edges must be forwarded to the same destination. */ |
1869 | if (fallthru1) | |
1870 | { | |
1871 | basic_block d1 = (forwarder_block_p (fallthru1->dest) | |
ea091dfd | 1872 | ? single_succ (fallthru1->dest): fallthru1->dest); |
ba38e12b | 1873 | basic_block d2 = (forwarder_block_p (fallthru2->dest) |
ea091dfd | 1874 | ? single_succ (fallthru2->dest): fallthru2->dest); |
5cc577b6 | 1875 | |
ba38e12b | 1876 | if (d1 != d2) |
1877 | return false; | |
1878 | } | |
5cc577b6 | 1879 | |
79f00c53 | 1880 | /* Ensure the same EH region. */ |
1881 | { | |
5496dbfc | 1882 | rtx n1 = find_reg_note (BB_END (bb1), REG_EH_REGION, 0); |
1883 | rtx n2 = find_reg_note (BB_END (bb2), REG_EH_REGION, 0); | |
5cc577b6 | 1884 | |
79f00c53 | 1885 | if (!n1 && n2) |
1886 | return false; | |
1887 | ||
1888 | if (n1 && (!n2 || XEXP (n1, 0) != XEXP (n2, 0))) | |
1889 | return false; | |
1890 | } | |
5cc577b6 | 1891 | |
89140b26 | 1892 | /* The same checks as in try_crossjump_to_edge. It is required for RTL |
1893 | version of sequence abstraction. */ | |
1894 | FOR_EACH_EDGE (e1, ei, bb2->succs) | |
1895 | { | |
1896 | edge e2; | |
1897 | edge_iterator ei; | |
1898 | basic_block d1 = e1->dest; | |
1899 | ||
1900 | if (FORWARDER_BLOCK_P (d1)) | |
1901 | d1 = EDGE_SUCC (d1, 0)->dest; | |
1902 | ||
1903 | FOR_EACH_EDGE (e2, ei, bb1->succs) | |
1904 | { | |
1905 | basic_block d2 = e2->dest; | |
1906 | if (FORWARDER_BLOCK_P (d2)) | |
1907 | d2 = EDGE_SUCC (d2, 0)->dest; | |
1908 | if (d1 == d2) | |
1909 | break; | |
1910 | } | |
1911 | ||
1912 | if (!e2) | |
1913 | return false; | |
1914 | } | |
1915 | ||
ba38e12b | 1916 | return true; |
65f34de5 | 1917 | } |
1918 | ||
89140b26 | 1919 | /* Returns true if BB basic block has a preserve label. */ |
1920 | ||
1921 | static bool | |
1922 | block_has_preserve_label (basic_block bb) | |
1923 | { | |
1924 | return (bb | |
1925 | && block_label (bb) | |
1926 | && LABEL_PRESERVE_P (block_label (bb))); | |
1927 | } | |
1928 | ||
65f34de5 | 1929 | /* E1 and E2 are edges with the same destination block. Search their |
1930 | predecessors for common code. If found, redirect control flow from | |
0f38cfdd | 1931 | (maybe the middle of) E1->SRC to (maybe the middle of) E2->SRC (dir_forward), |
1932 | or the other way around (dir_backward). DIR specifies the allowed | |
1933 | replacement direction. */ | |
65f34de5 | 1934 | |
1935 | static bool | |
0f38cfdd | 1936 | try_crossjump_to_edge (int mode, edge e1, edge e2, |
1937 | enum replace_direction dir) | |
65f34de5 | 1938 | { |
1d133110 | 1939 | int nmatch; |
65f34de5 | 1940 | basic_block src1 = e1->src, src2 = e2->src; |
42e9bc25 | 1941 | basic_block redirect_to, redirect_from, to_remove; |
4ef44dfa | 1942 | basic_block osrc1, osrc2, redirect_edges_to, tmp; |
c093ac49 | 1943 | rtx_insn *newpos1, *newpos2; |
65f34de5 | 1944 | edge s; |
cd665a06 | 1945 | edge_iterator ei; |
1d133110 | 1946 | |
c093ac49 | 1947 | newpos1 = newpos2 = NULL; |
4ee9c684 | 1948 | |
4f18499c | 1949 | /* If we have partitioned hot/cold basic blocks, it is a bad idea |
a0c938f0 | 1950 | to try this optimization. |
1118aef7 | 1951 | |
1952 | Basic block partitioning may result in some jumps that appear to | |
a0c938f0 | 1953 | be optimizable (or blocks that appear to be mergeable), but which really |
1954 | must be left untouched (they are required to make it safely across | |
1955 | partition boundaries). See the comments at the top of | |
1118aef7 | 1956 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
4f18499c | 1957 | |
812ca88e | 1958 | if (crtl->has_bb_partition && reload_completed) |
4f18499c | 1959 | return false; |
1960 | ||
65f34de5 | 1961 | /* Search backward through forwarder blocks. We don't need to worry |
1962 | about multiple entry or chained forwarders, as they will be optimized | |
1963 | away. We do this to look past the unconditional jump following a | |
1964 | conditional jump that is required due to the current CFG shape. */ | |
ea091dfd | 1965 | if (single_pred_p (src1) |
33dbe4d1 | 1966 | && FORWARDER_BLOCK_P (src1)) |
ea091dfd | 1967 | e1 = single_pred_edge (src1), src1 = e1->src; |
5cc577b6 | 1968 | |
ea091dfd | 1969 | if (single_pred_p (src2) |
33dbe4d1 | 1970 | && FORWARDER_BLOCK_P (src2)) |
ea091dfd | 1971 | e2 = single_pred_edge (src2), src2 = e2->src; |
65f34de5 | 1972 | |
1973 | /* Nothing to do if we reach ENTRY, or a common source block. */ | |
34154e27 | 1974 | if (src1 == ENTRY_BLOCK_PTR_FOR_FN (cfun) || src2 |
1975 | == ENTRY_BLOCK_PTR_FOR_FN (cfun)) | |
65f34de5 | 1976 | return false; |
1977 | if (src1 == src2) | |
1978 | return false; | |
1979 | ||
1980 | /* Seeing more than 1 forwarder blocks would confuse us later... */ | |
33dbe4d1 | 1981 | if (FORWARDER_BLOCK_P (e1->dest) |
ea091dfd | 1982 | && FORWARDER_BLOCK_P (single_succ (e1->dest))) |
65f34de5 | 1983 | return false; |
5cc577b6 | 1984 | |
33dbe4d1 | 1985 | if (FORWARDER_BLOCK_P (e2->dest) |
ea091dfd | 1986 | && FORWARDER_BLOCK_P (single_succ (e2->dest))) |
65f34de5 | 1987 | return false; |
1988 | ||
1989 | /* Likewise with dead code (possibly newly created by the other optimizations | |
1990 | of cfg_cleanup). */ | |
cd665a06 | 1991 | if (EDGE_COUNT (src1->preds) == 0 || EDGE_COUNT (src2->preds) == 0) |
65f34de5 | 1992 | return false; |
1993 | ||
65f34de5 | 1994 | /* Look for the common insn sequence, part the first ... */ |
1d133110 | 1995 | if (!outgoing_edges_match (mode, src1, src2)) |
65f34de5 | 1996 | return false; |
1997 | ||
1998 | /* ... and part the second. */ | |
764aef11 | 1999 | nmatch = flow_find_cross_jump (src1, src2, &newpos1, &newpos2, &dir); |
43341e2f | 2000 | |
4ef44dfa | 2001 | osrc1 = src1; |
2002 | osrc2 = src2; | |
2003 | if (newpos1 != NULL_RTX) | |
2004 | src1 = BLOCK_FOR_INSN (newpos1); | |
2005 | if (newpos2 != NULL_RTX) | |
2006 | src2 = BLOCK_FOR_INSN (newpos2); | |
2007 | ||
0f38cfdd | 2008 | if (dir == dir_backward) |
2009 | { | |
2010 | #define SWAP(T, X, Y) do { T tmp = (X); (X) = (Y); (Y) = tmp; } while (0) | |
2011 | SWAP (basic_block, osrc1, osrc2); | |
2012 | SWAP (basic_block, src1, src2); | |
2013 | SWAP (edge, e1, e2); | |
c093ac49 | 2014 | SWAP (rtx_insn *, newpos1, newpos2); |
0f38cfdd | 2015 | #undef SWAP |
2016 | } | |
2017 | ||
43341e2f | 2018 | /* Don't proceed with the crossjump unless we found a sufficient number |
2019 | of matching instructions or the 'from' block was totally matched | |
2020 | (such that its predecessors will hopefully be redirected and the | |
2021 | block removed). */ | |
1d133110 | 2022 | if ((nmatch < PARAM_VALUE (PARAM_MIN_CROSSJUMP_INSNS)) |
2023 | && (newpos1 != BB_HEAD (src1))) | |
cd7f40a2 | 2024 | return false; |
65f34de5 | 2025 | |
d961ae3a | 2026 | /* Avoid deleting preserve label when redirecting ABNORMAL edges. */ |
89140b26 | 2027 | if (block_has_preserve_label (e1->dest) |
2028 | && (e1->flags & EDGE_ABNORMAL)) | |
2029 | return false; | |
2030 | ||
f2756aab | 2031 | /* Here we know that the insns in the end of SRC1 which are common with SRC2 |
2032 | will be deleted. | |
2033 | If we have tablejumps in the end of SRC1 and SRC2 | |
2034 | they have been already compared for equivalence in outgoing_edges_match () | |
2035 | so replace the references to TABLE1 by references to TABLE2. */ | |
5c6f6a61 | 2036 | { |
f2756aab | 2037 | rtx label1, label2; |
c86d86ff | 2038 | rtx_jump_table_data *table1, *table2; |
f2756aab | 2039 | |
4ef44dfa | 2040 | if (tablejump_p (BB_END (osrc1), &label1, &table1) |
2041 | && tablejump_p (BB_END (osrc2), &label2, &table2) | |
f2756aab | 2042 | && label1 != label2) |
2043 | { | |
c093ac49 | 2044 | rtx_insn *insn; |
f2756aab | 2045 | |
2046 | /* Replace references to LABEL1 with LABEL2. */ | |
f2756aab | 2047 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) |
2048 | { | |
2049 | /* Do not replace the label in SRC1->END because when deleting | |
2050 | a block whose end is a tablejump, the tablejump referenced | |
2051 | from the instruction is deleted too. */ | |
4ef44dfa | 2052 | if (insn != BB_END (osrc1)) |
956816a2 | 2053 | replace_label_in_insn (insn, label1, label2, true); |
f2756aab | 2054 | } |
2055 | } | |
5c6f6a61 | 2056 | } |
63b616bf | 2057 | |
12ea1478 | 2058 | /* Avoid splitting if possible. We must always split when SRC2 has |
2059 | EH predecessor edges, or we may end up with basic blocks with both | |
2060 | normal and EH predecessor edges. */ | |
1d133110 | 2061 | if (newpos2 == BB_HEAD (src2) |
12ea1478 | 2062 | && !(EDGE_PRED (src2, 0)->flags & EDGE_EH)) |
65f34de5 | 2063 | redirect_to = src2; |
2064 | else | |
2065 | { | |
1d133110 | 2066 | if (newpos2 == BB_HEAD (src2)) |
12ea1478 | 2067 | { |
2068 | /* Skip possible basic block header. */ | |
1d133110 | 2069 | if (LABEL_P (newpos2)) |
2070 | newpos2 = NEXT_INSN (newpos2); | |
9845d120 | 2071 | while (DEBUG_INSN_P (newpos2)) |
2072 | newpos2 = NEXT_INSN (newpos2); | |
1d133110 | 2073 | if (NOTE_P (newpos2)) |
2074 | newpos2 = NEXT_INSN (newpos2); | |
9845d120 | 2075 | while (DEBUG_INSN_P (newpos2)) |
2076 | newpos2 = NEXT_INSN (newpos2); | |
12ea1478 | 2077 | } |
2078 | ||
450d042a | 2079 | if (dump_file) |
2080 | fprintf (dump_file, "Splitting bb %i before %i insns\n", | |
b3d6de89 | 2081 | src2->index, nmatch); |
1d133110 | 2082 | redirect_to = split_block (src2, PREV_INSN (newpos2))->dest; |
65f34de5 | 2083 | } |
2084 | ||
450d042a | 2085 | if (dump_file) |
1d133110 | 2086 | fprintf (dump_file, |
2087 | "Cross jumping from bb %i to bb %i; %i common insns\n", | |
2088 | src1->index, src2->index, nmatch); | |
65f34de5 | 2089 | |
554f2707 | 2090 | /* We may have some registers visible through the block. */ |
3072d30e | 2091 | df_set_bb_dirty (redirect_to); |
65f34de5 | 2092 | |
4ef44dfa | 2093 | if (osrc2 == src2) |
2094 | redirect_edges_to = redirect_to; | |
2095 | else | |
2096 | redirect_edges_to = osrc2; | |
2097 | ||
65f34de5 | 2098 | /* Recompute the frequencies and counts of outgoing edges. */ |
4ef44dfa | 2099 | FOR_EACH_EDGE (s, ei, redirect_edges_to->succs) |
65f34de5 | 2100 | { |
2101 | edge s2; | |
cd665a06 | 2102 | edge_iterator ei; |
65f34de5 | 2103 | basic_block d = s->dest; |
2104 | ||
33dbe4d1 | 2105 | if (FORWARDER_BLOCK_P (d)) |
ea091dfd | 2106 | d = single_succ (d); |
5cc577b6 | 2107 | |
cd665a06 | 2108 | FOR_EACH_EDGE (s2, ei, src1->succs) |
65f34de5 | 2109 | { |
2110 | basic_block d2 = s2->dest; | |
33dbe4d1 | 2111 | if (FORWARDER_BLOCK_P (d2)) |
ea091dfd | 2112 | d2 = single_succ (d2); |
65f34de5 | 2113 | if (d == d2) |
2114 | break; | |
2115 | } | |
5cc577b6 | 2116 | |
65f34de5 | 2117 | s->count += s2->count; |
2118 | ||
2119 | /* Take care to update possible forwarder blocks. We verified | |
a0c938f0 | 2120 | that there is no more than one in the chain, so we can't run |
2121 | into infinite loop. */ | |
33dbe4d1 | 2122 | if (FORWARDER_BLOCK_P (s->dest)) |
65f34de5 | 2123 | { |
ea091dfd | 2124 | single_succ_edge (s->dest)->count += s2->count; |
65f34de5 | 2125 | s->dest->count += s2->count; |
2126 | s->dest->frequency += EDGE_FREQUENCY (s); | |
2127 | } | |
5cc577b6 | 2128 | |
33dbe4d1 | 2129 | if (FORWARDER_BLOCK_P (s2->dest)) |
65f34de5 | 2130 | { |
ea091dfd | 2131 | single_succ_edge (s2->dest)->count -= s2->count; |
2132 | if (single_succ_edge (s2->dest)->count < 0) | |
2133 | single_succ_edge (s2->dest)->count = 0; | |
65f34de5 | 2134 | s2->dest->count -= s2->count; |
2135 | s2->dest->frequency -= EDGE_FREQUENCY (s); | |
f884e43f | 2136 | if (s2->dest->frequency < 0) |
2137 | s2->dest->frequency = 0; | |
2138 | if (s2->dest->count < 0) | |
2139 | s2->dest->count = 0; | |
65f34de5 | 2140 | } |
5cc577b6 | 2141 | |
4ef44dfa | 2142 | if (!redirect_edges_to->frequency && !src1->frequency) |
65f34de5 | 2143 | s->probability = (s->probability + s2->probability) / 2; |
2144 | else | |
5cc577b6 | 2145 | s->probability |
4ef44dfa | 2146 | = ((s->probability * redirect_edges_to->frequency + |
5cc577b6 | 2147 | s2->probability * src1->frequency) |
4ef44dfa | 2148 | / (redirect_edges_to->frequency + src1->frequency)); |
65f34de5 | 2149 | } |
2150 | ||
8c09e55e | 2151 | /* Adjust count and frequency for the block. An earlier jump |
2152 | threading pass may have left the profile in an inconsistent | |
2153 | state (see update_bb_profile_for_threading) so we must be | |
2154 | prepared for overflows. */ | |
4ef44dfa | 2155 | tmp = redirect_to; |
2156 | do | |
2157 | { | |
2158 | tmp->count += src1->count; | |
2159 | tmp->frequency += src1->frequency; | |
2160 | if (tmp->frequency > BB_FREQ_MAX) | |
2161 | tmp->frequency = BB_FREQ_MAX; | |
2162 | if (tmp == redirect_edges_to) | |
2163 | break; | |
2164 | tmp = find_fallthru_edge (tmp->succs)->dest; | |
2165 | } | |
2166 | while (true); | |
2167 | update_br_prob_note (redirect_edges_to); | |
65f34de5 | 2168 | |
2169 | /* Edit SRC1 to go to REDIRECT_TO at NEWPOS1. */ | |
2170 | ||
1d133110 | 2171 | /* Skip possible basic block header. */ |
2172 | if (LABEL_P (newpos1)) | |
2173 | newpos1 = NEXT_INSN (newpos1); | |
9845d120 | 2174 | |
2175 | while (DEBUG_INSN_P (newpos1)) | |
2176 | newpos1 = NEXT_INSN (newpos1); | |
2177 | ||
25e880b1 | 2178 | if (NOTE_INSN_BASIC_BLOCK_P (newpos1)) |
1d133110 | 2179 | newpos1 = NEXT_INSN (newpos1); |
2180 | ||
9845d120 | 2181 | while (DEBUG_INSN_P (newpos1)) |
2182 | newpos1 = NEXT_INSN (newpos1); | |
2183 | ||
1d133110 | 2184 | redirect_from = split_block (src1, PREV_INSN (newpos1))->src; |
ea091dfd | 2185 | to_remove = single_succ (redirect_from); |
65f34de5 | 2186 | |
ea091dfd | 2187 | redirect_edge_and_branch_force (single_succ_edge (redirect_from), redirect_to); |
5f5d4cd1 | 2188 | delete_basic_block (to_remove); |
65f34de5 | 2189 | |
42e9bc25 | 2190 | update_forwarder_flag (redirect_from); |
30ad61ed | 2191 | if (redirect_to != src2) |
2192 | update_forwarder_flag (src2); | |
33dbe4d1 | 2193 | |
65f34de5 | 2194 | return true; |
2195 | } | |
2196 | ||
2197 | /* Search the predecessors of BB for common insn sequences. When found, | |
2198 | share code between them by redirecting control flow. Return true if | |
2199 | any changes made. */ | |
2200 | ||
2201 | static bool | |
4c9e08a4 | 2202 | try_crossjump_bb (int mode, basic_block bb) |
65f34de5 | 2203 | { |
cd665a06 | 2204 | edge e, e2, fallthru; |
65f34de5 | 2205 | bool changed; |
cd665a06 | 2206 | unsigned max, ix, ix2; |
65f34de5 | 2207 | |
dd5b4b36 | 2208 | /* Nothing to do if there is not at least two incoming edges. */ |
cd665a06 | 2209 | if (EDGE_COUNT (bb->preds) < 2) |
65f34de5 | 2210 | return false; |
2211 | ||
b70a5a99 | 2212 | /* Don't crossjump if this block ends in a computed jump, |
2213 | unless we are optimizing for size. */ | |
0bfd8d5c | 2214 | if (optimize_bb_for_size_p (bb) |
34154e27 | 2215 | && bb != EXIT_BLOCK_PTR_FOR_FN (cfun) |
b70a5a99 | 2216 | && computed_jump_p (BB_END (bb))) |
2217 | return false; | |
2218 | ||
4f18499c | 2219 | /* If we are partitioning hot/cold basic blocks, we don't want to |
2220 | mess up unconditional or indirect jumps that cross between hot | |
a0c938f0 | 2221 | and cold sections. |
2222 | ||
1118aef7 | 2223 | Basic block partitioning may result in some jumps that appear to |
a0c938f0 | 2224 | be optimizable (or blocks that appear to be mergeable), but which really |
2225 | must be left untouched (they are required to make it safely across | |
2226 | partition boundaries). See the comments at the top of | |
1118aef7 | 2227 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
2228 | ||
a0c938f0 | 2229 | if (BB_PARTITION (EDGE_PRED (bb, 0)->src) != |
2230 | BB_PARTITION (EDGE_PRED (bb, 1)->src) | |
1897b881 | 2231 | || (EDGE_PRED (bb, 0)->flags & EDGE_CROSSING)) |
4f18499c | 2232 | return false; |
2233 | ||
65f34de5 | 2234 | /* It is always cheapest to redirect a block that ends in a branch to |
2235 | a block that falls through into BB, as that adds no branches to the | |
2236 | program. We'll try that combination first. */ | |
2a5b4716 | 2237 | fallthru = NULL; |
2238 | max = PARAM_VALUE (PARAM_MAX_CROSSJUMP_EDGES); | |
cd665a06 | 2239 | |
2240 | if (EDGE_COUNT (bb->preds) > max) | |
2241 | return false; | |
2242 | ||
7f58c05e | 2243 | fallthru = find_fallthru_edge (bb->preds); |
65f34de5 | 2244 | |
2245 | changed = false; | |
e8911909 | 2246 | for (ix = 0; ix < EDGE_COUNT (bb->preds);) |
65f34de5 | 2247 | { |
e8911909 | 2248 | e = EDGE_PRED (bb, ix); |
cd665a06 | 2249 | ix++; |
65f34de5 | 2250 | |
1ae2ffa7 | 2251 | /* As noted above, first try with the fallthru predecessor (or, a |
2252 | fallthru predecessor if we are in cfglayout mode). */ | |
65f34de5 | 2253 | if (fallthru) |
2254 | { | |
2255 | /* Don't combine the fallthru edge into anything else. | |
2256 | If there is a match, we'll do it the other way around. */ | |
2257 | if (e == fallthru) | |
2258 | continue; | |
10d3796f | 2259 | /* If nothing changed since the last attempt, there is nothing |
2260 | we can do. */ | |
2261 | if (!first_pass | |
bc6adae4 | 2262 | && !((e->src->flags & BB_MODIFIED) |
2263 | || (fallthru->src->flags & BB_MODIFIED))) | |
10d3796f | 2264 | continue; |
65f34de5 | 2265 | |
0f38cfdd | 2266 | if (try_crossjump_to_edge (mode, e, fallthru, dir_forward)) |
65f34de5 | 2267 | { |
2268 | changed = true; | |
cd665a06 | 2269 | ix = 0; |
65f34de5 | 2270 | continue; |
2271 | } | |
2272 | } | |
2273 | ||
2274 | /* Non-obvious work limiting check: Recognize that we're going | |
2275 | to call try_crossjump_bb on every basic block. So if we have | |
2276 | two blocks with lots of outgoing edges (a switch) and they | |
2277 | share lots of common destinations, then we would do the | |
2278 | cross-jump check once for each common destination. | |
2279 | ||
2280 | Now, if the blocks actually are cross-jump candidates, then | |
2281 | all of their destinations will be shared. Which means that | |
2282 | we only need check them for cross-jump candidacy once. We | |
2283 | can eliminate redundant checks of crossjump(A,B) by arbitrarily | |
2284 | choosing to do the check from the block for which the edge | |
2285 | in question is the first successor of A. */ | |
cd665a06 | 2286 | if (EDGE_SUCC (e->src, 0) != e) |
65f34de5 | 2287 | continue; |
2288 | ||
e8911909 | 2289 | for (ix2 = 0; ix2 < EDGE_COUNT (bb->preds); ix2++) |
65f34de5 | 2290 | { |
e8911909 | 2291 | e2 = EDGE_PRED (bb, ix2); |
65f34de5 | 2292 | |
2293 | if (e2 == e) | |
2294 | continue; | |
2295 | ||
2296 | /* We've already checked the fallthru edge above. */ | |
2297 | if (e2 == fallthru) | |
2298 | continue; | |
2299 | ||
65f34de5 | 2300 | /* The "first successor" check above only prevents multiple |
2301 | checks of crossjump(A,B). In order to prevent redundant | |
2302 | checks of crossjump(B,A), require that A be the block | |
2303 | with the lowest index. */ | |
b3d6de89 | 2304 | if (e->src->index > e2->src->index) |
65f34de5 | 2305 | continue; |
2306 | ||
10d3796f | 2307 | /* If nothing changed since the last attempt, there is nothing |
2308 | we can do. */ | |
2309 | if (!first_pass | |
bc6adae4 | 2310 | && !((e->src->flags & BB_MODIFIED) |
2311 | || (e2->src->flags & BB_MODIFIED))) | |
10d3796f | 2312 | continue; |
2313 | ||
0f38cfdd | 2314 | /* Both e and e2 are not fallthru edges, so we can crossjump in either |
2315 | direction. */ | |
2316 | if (try_crossjump_to_edge (mode, e, e2, dir_both)) | |
65f34de5 | 2317 | { |
2318 | changed = true; | |
cd665a06 | 2319 | ix = 0; |
65f34de5 | 2320 | break; |
2321 | } | |
2322 | } | |
2323 | } | |
2324 | ||
1ae2ffa7 | 2325 | if (changed) |
2326 | crossjumps_occured = true; | |
2327 | ||
65f34de5 | 2328 | return changed; |
2329 | } | |
2330 | ||
bc6adae4 | 2331 | /* Search the successors of BB for common insn sequences. When found, |
2332 | share code between them by moving it across the basic block | |
2333 | boundary. Return true if any changes made. */ | |
2334 | ||
2335 | static bool | |
2336 | try_head_merge_bb (basic_block bb) | |
2337 | { | |
2338 | basic_block final_dest_bb = NULL; | |
2339 | int max_match = INT_MAX; | |
2340 | edge e0; | |
c093ac49 | 2341 | rtx_insn **headptr, **currptr, **nextptr; |
bc6adae4 | 2342 | bool changed, moveall; |
2343 | unsigned ix; | |
c093ac49 | 2344 | rtx_insn *e0_last_head; |
2d650f54 | 2345 | rtx cond; |
2346 | rtx_insn *move_before; | |
bc6adae4 | 2347 | unsigned nedges = EDGE_COUNT (bb->succs); |
c093ac49 | 2348 | rtx_insn *jump = BB_END (bb); |
bc6adae4 | 2349 | regset live, live_union; |
2350 | ||
2351 | /* Nothing to do if there is not at least two outgoing edges. */ | |
2352 | if (nedges < 2) | |
2353 | return false; | |
2354 | ||
2355 | /* Don't crossjump if this block ends in a computed jump, | |
2356 | unless we are optimizing for size. */ | |
2357 | if (optimize_bb_for_size_p (bb) | |
34154e27 | 2358 | && bb != EXIT_BLOCK_PTR_FOR_FN (cfun) |
bc6adae4 | 2359 | && computed_jump_p (BB_END (bb))) |
2360 | return false; | |
2361 | ||
2362 | cond = get_condition (jump, &move_before, true, false); | |
2363 | if (cond == NULL_RTX) | |
3cc98df4 | 2364 | { |
693c9f42 | 2365 | if (HAVE_cc0 && reg_mentioned_p (cc0_rtx, jump)) |
3cc98df4 | 2366 | move_before = prev_nonnote_nondebug_insn (jump); |
2367 | else | |
3cc98df4 | 2368 | move_before = jump; |
2369 | } | |
bc6adae4 | 2370 | |
2371 | for (ix = 0; ix < nedges; ix++) | |
34154e27 | 2372 | if (EDGE_SUCC (bb, ix)->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
bc6adae4 | 2373 | return false; |
2374 | ||
2375 | for (ix = 0; ix < nedges; ix++) | |
2376 | { | |
2377 | edge e = EDGE_SUCC (bb, ix); | |
2378 | basic_block other_bb = e->dest; | |
2379 | ||
2380 | if (df_get_bb_dirty (other_bb)) | |
2381 | { | |
2382 | block_was_dirty = true; | |
2383 | return false; | |
2384 | } | |
2385 | ||
2386 | if (e->flags & EDGE_ABNORMAL) | |
2387 | return false; | |
2388 | ||
2389 | /* Normally, all destination blocks must only be reachable from this | |
2390 | block, i.e. they must have one incoming edge. | |
2391 | ||
2392 | There is one special case we can handle, that of multiple consecutive | |
2393 | jumps where the first jumps to one of the targets of the second jump. | |
2394 | This happens frequently in switch statements for default labels. | |
2395 | The structure is as follows: | |
2396 | FINAL_DEST_BB | |
2397 | .... | |
2398 | if (cond) jump A; | |
2399 | fall through | |
2400 | BB | |
2401 | jump with targets A, B, C, D... | |
2402 | A | |
2403 | has two incoming edges, from FINAL_DEST_BB and BB | |
2404 | ||
2405 | In this case, we can try to move the insns through BB and into | |
2406 | FINAL_DEST_BB. */ | |
2407 | if (EDGE_COUNT (other_bb->preds) != 1) | |
2408 | { | |
2409 | edge incoming_edge, incoming_bb_other_edge; | |
2410 | edge_iterator ei; | |
2411 | ||
2412 | if (final_dest_bb != NULL | |
2413 | || EDGE_COUNT (other_bb->preds) != 2) | |
2414 | return false; | |
2415 | ||
2416 | /* We must be able to move the insns across the whole block. */ | |
2417 | move_before = BB_HEAD (bb); | |
2418 | while (!NONDEBUG_INSN_P (move_before)) | |
2419 | move_before = NEXT_INSN (move_before); | |
2420 | ||
2421 | if (EDGE_COUNT (bb->preds) != 1) | |
2422 | return false; | |
2423 | incoming_edge = EDGE_PRED (bb, 0); | |
2424 | final_dest_bb = incoming_edge->src; | |
2425 | if (EDGE_COUNT (final_dest_bb->succs) != 2) | |
2426 | return false; | |
2427 | FOR_EACH_EDGE (incoming_bb_other_edge, ei, final_dest_bb->succs) | |
2428 | if (incoming_bb_other_edge != incoming_edge) | |
2429 | break; | |
2430 | if (incoming_bb_other_edge->dest != other_bb) | |
2431 | return false; | |
2432 | } | |
2433 | } | |
2434 | ||
2435 | e0 = EDGE_SUCC (bb, 0); | |
c093ac49 | 2436 | e0_last_head = NULL; |
bc6adae4 | 2437 | changed = false; |
2438 | ||
2439 | for (ix = 1; ix < nedges; ix++) | |
2440 | { | |
2441 | edge e = EDGE_SUCC (bb, ix); | |
c093ac49 | 2442 | rtx_insn *e0_last, *e_last; |
bc6adae4 | 2443 | int nmatch; |
2444 | ||
2445 | nmatch = flow_find_head_matching_sequence (e0->dest, e->dest, | |
2446 | &e0_last, &e_last, 0); | |
2447 | if (nmatch == 0) | |
2448 | return false; | |
2449 | ||
2450 | if (nmatch < max_match) | |
2451 | { | |
2452 | max_match = nmatch; | |
2453 | e0_last_head = e0_last; | |
2454 | } | |
2455 | } | |
2456 | ||
2457 | /* If we matched an entire block, we probably have to avoid moving the | |
2458 | last insn. */ | |
2459 | if (max_match > 0 | |
2460 | && e0_last_head == BB_END (e0->dest) | |
2461 | && (find_reg_note (e0_last_head, REG_EH_REGION, 0) | |
2462 | || control_flow_insn_p (e0_last_head))) | |
2463 | { | |
2464 | max_match--; | |
2465 | if (max_match == 0) | |
2466 | return false; | |
964c7827 | 2467 | do |
2468 | e0_last_head = prev_real_insn (e0_last_head); | |
2469 | while (DEBUG_INSN_P (e0_last_head)); | |
bc6adae4 | 2470 | } |
2471 | ||
2472 | if (max_match == 0) | |
2473 | return false; | |
2474 | ||
2475 | /* We must find a union of the live registers at each of the end points. */ | |
2476 | live = BITMAP_ALLOC (NULL); | |
2477 | live_union = BITMAP_ALLOC (NULL); | |
2478 | ||
c093ac49 | 2479 | currptr = XNEWVEC (rtx_insn *, nedges); |
2480 | headptr = XNEWVEC (rtx_insn *, nedges); | |
2481 | nextptr = XNEWVEC (rtx_insn *, nedges); | |
bc6adae4 | 2482 | |
2483 | for (ix = 0; ix < nedges; ix++) | |
2484 | { | |
2485 | int j; | |
2486 | basic_block merge_bb = EDGE_SUCC (bb, ix)->dest; | |
c093ac49 | 2487 | rtx_insn *head = BB_HEAD (merge_bb); |
bc6adae4 | 2488 | |
964c7827 | 2489 | while (!NONDEBUG_INSN_P (head)) |
2490 | head = NEXT_INSN (head); | |
bc6adae4 | 2491 | headptr[ix] = head; |
2492 | currptr[ix] = head; | |
2493 | ||
2494 | /* Compute the end point and live information */ | |
2495 | for (j = 1; j < max_match; j++) | |
964c7827 | 2496 | do |
2497 | head = NEXT_INSN (head); | |
2498 | while (!NONDEBUG_INSN_P (head)); | |
bc6adae4 | 2499 | simulate_backwards_to_point (merge_bb, live, head); |
2500 | IOR_REG_SET (live_union, live); | |
2501 | } | |
2502 | ||
2503 | /* If we're moving across two blocks, verify the validity of the | |
2504 | first move, then adjust the target and let the loop below deal | |
2505 | with the final move. */ | |
2506 | if (final_dest_bb != NULL) | |
2507 | { | |
2d650f54 | 2508 | rtx_insn *move_upto; |
bc6adae4 | 2509 | |
2510 | moveall = can_move_insns_across (currptr[0], e0_last_head, move_before, | |
2511 | jump, e0->dest, live_union, | |
2512 | NULL, &move_upto); | |
2513 | if (!moveall) | |
2514 | { | |
2515 | if (move_upto == NULL_RTX) | |
2516 | goto out; | |
2517 | ||
2518 | while (e0_last_head != move_upto) | |
2519 | { | |
2520 | df_simulate_one_insn_backwards (e0->dest, e0_last_head, | |
2521 | live_union); | |
2522 | e0_last_head = PREV_INSN (e0_last_head); | |
2523 | } | |
2524 | } | |
2525 | if (e0_last_head == NULL_RTX) | |
2526 | goto out; | |
2527 | ||
2528 | jump = BB_END (final_dest_bb); | |
2529 | cond = get_condition (jump, &move_before, true, false); | |
2530 | if (cond == NULL_RTX) | |
3cc98df4 | 2531 | { |
693c9f42 | 2532 | if (HAVE_cc0 && reg_mentioned_p (cc0_rtx, jump)) |
3cc98df4 | 2533 | move_before = prev_nonnote_nondebug_insn (jump); |
2534 | else | |
3cc98df4 | 2535 | move_before = jump; |
2536 | } | |
bc6adae4 | 2537 | } |
2538 | ||
2539 | do | |
2540 | { | |
2d650f54 | 2541 | rtx_insn *move_upto; |
bc6adae4 | 2542 | moveall = can_move_insns_across (currptr[0], e0_last_head, |
2543 | move_before, jump, e0->dest, live_union, | |
2544 | NULL, &move_upto); | |
2545 | if (!moveall && move_upto == NULL_RTX) | |
2546 | { | |
2547 | if (jump == move_before) | |
2548 | break; | |
2549 | ||
2550 | /* Try again, using a different insertion point. */ | |
2551 | move_before = jump; | |
2552 | ||
bc6adae4 | 2553 | /* Don't try moving before a cc0 user, as that may invalidate |
2554 | the cc0. */ | |
693c9f42 | 2555 | if (HAVE_cc0 && reg_mentioned_p (cc0_rtx, jump)) |
bc6adae4 | 2556 | break; |
bc6adae4 | 2557 | |
2558 | continue; | |
2559 | } | |
2560 | ||
2561 | if (final_dest_bb && !moveall) | |
2562 | /* We haven't checked whether a partial move would be OK for the first | |
2563 | move, so we have to fail this case. */ | |
2564 | break; | |
2565 | ||
2566 | changed = true; | |
2567 | for (;;) | |
2568 | { | |
2569 | if (currptr[0] == move_upto) | |
2570 | break; | |
2571 | for (ix = 0; ix < nedges; ix++) | |
2572 | { | |
c093ac49 | 2573 | rtx_insn *curr = currptr[ix]; |
bc6adae4 | 2574 | do |
2575 | curr = NEXT_INSN (curr); | |
2576 | while (!NONDEBUG_INSN_P (curr)); | |
2577 | currptr[ix] = curr; | |
2578 | } | |
2579 | } | |
2580 | ||
2581 | /* If we can't currently move all of the identical insns, remember | |
2582 | each insn after the range that we'll merge. */ | |
2583 | if (!moveall) | |
2584 | for (ix = 0; ix < nedges; ix++) | |
2585 | { | |
c093ac49 | 2586 | rtx_insn *curr = currptr[ix]; |
bc6adae4 | 2587 | do |
2588 | curr = NEXT_INSN (curr); | |
2589 | while (!NONDEBUG_INSN_P (curr)); | |
2590 | nextptr[ix] = curr; | |
2591 | } | |
2592 | ||
2593 | reorder_insns (headptr[0], currptr[0], PREV_INSN (move_before)); | |
2594 | df_set_bb_dirty (EDGE_SUCC (bb, 0)->dest); | |
2595 | if (final_dest_bb != NULL) | |
2596 | df_set_bb_dirty (final_dest_bb); | |
2597 | df_set_bb_dirty (bb); | |
2598 | for (ix = 1; ix < nedges; ix++) | |
2599 | { | |
2600 | df_set_bb_dirty (EDGE_SUCC (bb, ix)->dest); | |
2601 | delete_insn_chain (headptr[ix], currptr[ix], false); | |
2602 | } | |
2603 | if (!moveall) | |
2604 | { | |
2605 | if (jump == move_before) | |
2606 | break; | |
2607 | ||
2608 | /* For the unmerged insns, try a different insertion point. */ | |
2609 | move_before = jump; | |
2610 | ||
bc6adae4 | 2611 | /* Don't try moving before a cc0 user, as that may invalidate |
2612 | the cc0. */ | |
693c9f42 | 2613 | if (HAVE_cc0 && reg_mentioned_p (cc0_rtx, jump)) |
bc6adae4 | 2614 | break; |
bc6adae4 | 2615 | |
2616 | for (ix = 0; ix < nedges; ix++) | |
2617 | currptr[ix] = headptr[ix] = nextptr[ix]; | |
2618 | } | |
2619 | } | |
2620 | while (!moveall); | |
2621 | ||
2622 | out: | |
2623 | free (currptr); | |
2624 | free (headptr); | |
2625 | free (nextptr); | |
2626 | ||
2627 | crossjumps_occured |= changed; | |
2628 | ||
2629 | return changed; | |
2630 | } | |
2631 | ||
17d1c688 | 2632 | /* Return true if BB contains just bb note, or bb note followed |
2633 | by only DEBUG_INSNs. */ | |
2634 | ||
2635 | static bool | |
2636 | trivially_empty_bb_p (basic_block bb) | |
2637 | { | |
c093ac49 | 2638 | rtx_insn *insn = BB_END (bb); |
17d1c688 | 2639 | |
2640 | while (1) | |
2641 | { | |
2642 | if (insn == BB_HEAD (bb)) | |
2643 | return true; | |
2644 | if (!DEBUG_INSN_P (insn)) | |
2645 | return false; | |
2646 | insn = PREV_INSN (insn); | |
2647 | } | |
2648 | } | |
2649 | ||
65f34de5 | 2650 | /* Do simple CFG optimizations - basic block merging, simplifying of jump |
2651 | instructions etc. Return nonzero if changes were made. */ | |
2652 | ||
2653 | static bool | |
4c9e08a4 | 2654 | try_optimize_cfg (int mode) |
65f34de5 | 2655 | { |
65f34de5 | 2656 | bool changed_overall = false; |
2657 | bool changed; | |
2658 | int iterations = 0; | |
9d574a94 | 2659 | basic_block bb, b, next; |
65f34de5 | 2660 | |
3072d30e | 2661 | if (mode & (CLEANUP_CROSSJUMP | CLEANUP_THREADING)) |
308f9b79 | 2662 | clear_bb_flags (); |
2663 | ||
1ae2ffa7 | 2664 | crossjumps_occured = false; |
2665 | ||
fc00614f | 2666 | FOR_EACH_BB_FN (bb, cfun) |
4fe5a223 | 2667 | update_forwarder_flag (bb); |
2668 | ||
6fb33aa0 | 2669 | if (! targetm.cannot_modify_jumps_p ()) |
65f34de5 | 2670 | { |
10d3796f | 2671 | first_pass = true; |
e27e52e0 | 2672 | /* Attempt to merge blocks as made possible by edge removal. If |
2673 | a block has only one successor, and the successor has only | |
2674 | one predecessor, they may be combined. */ | |
2675 | do | |
65f34de5 | 2676 | { |
bc6adae4 | 2677 | block_was_dirty = false; |
e27e52e0 | 2678 | changed = false; |
2679 | iterations++; | |
2680 | ||
450d042a | 2681 | if (dump_file) |
2682 | fprintf (dump_file, | |
e27e52e0 | 2683 | "\n\ntry_optimize_cfg iteration %i\n\n", |
2684 | iterations); | |
65f34de5 | 2685 | |
34154e27 | 2686 | for (b = ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb; b |
2687 | != EXIT_BLOCK_PTR_FOR_FN (cfun);) | |
65f34de5 | 2688 | { |
4c26117a | 2689 | basic_block c; |
e27e52e0 | 2690 | edge s; |
2691 | bool changed_here = false; | |
5cc577b6 | 2692 | |
d2b48f0c | 2693 | /* Delete trivially dead basic blocks. This is either |
2694 | blocks with no predecessors, or empty blocks with no | |
c4d13c5c | 2695 | successors. However if the empty block with no |
2696 | successors is the successor of the ENTRY_BLOCK, it is | |
2697 | kept. This ensures that the ENTRY_BLOCK will have a | |
2698 | successor which is a precondition for many RTL | |
2699 | passes. Empty blocks may result from expanding | |
d2b48f0c | 2700 | __builtin_unreachable (). */ |
2701 | if (EDGE_COUNT (b->preds) == 0 | |
c4d13c5c | 2702 | || (EDGE_COUNT (b->succs) == 0 |
17d1c688 | 2703 | && trivially_empty_bb_p (b) |
34154e27 | 2704 | && single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun))->dest |
2705 | != b)) | |
e27e52e0 | 2706 | { |
345ac34a | 2707 | c = b->prev_bb; |
625a1adc | 2708 | if (EDGE_COUNT (b->preds) > 0) |
dcb172b4 | 2709 | { |
2710 | edge e; | |
2711 | edge_iterator ei; | |
2712 | ||
625a1adc | 2713 | if (current_ir_type () == IR_RTL_CFGLAYOUT) |
2714 | { | |
43e94e51 | 2715 | if (BB_FOOTER (b) |
2716 | && BARRIER_P (BB_FOOTER (b))) | |
625a1adc | 2717 | FOR_EACH_EDGE (e, ei, b->preds) |
2718 | if ((e->flags & EDGE_FALLTHRU) | |
43e94e51 | 2719 | && BB_FOOTER (e->src) == NULL) |
625a1adc | 2720 | { |
43e94e51 | 2721 | if (BB_FOOTER (b)) |
625a1adc | 2722 | { |
943ea6fa | 2723 | BB_FOOTER (e->src) = BB_FOOTER (b); |
2724 | BB_FOOTER (b) = NULL; | |
625a1adc | 2725 | } |
2726 | else | |
2727 | { | |
2728 | start_sequence (); | |
943ea6fa | 2729 | BB_FOOTER (e->src) = emit_barrier (); |
625a1adc | 2730 | end_sequence (); |
2731 | } | |
2732 | } | |
2733 | } | |
2734 | else | |
2735 | { | |
c093ac49 | 2736 | rtx_insn *last = get_last_bb_insn (b); |
625a1adc | 2737 | if (last && BARRIER_P (last)) |
2738 | FOR_EACH_EDGE (e, ei, b->preds) | |
2739 | if ((e->flags & EDGE_FALLTHRU)) | |
2740 | emit_barrier_after (BB_END (e->src)); | |
2741 | } | |
dcb172b4 | 2742 | } |
5f5d4cd1 | 2743 | delete_basic_block (b); |
2decfaa7 | 2744 | changed = true; |
efee62d1 | 2745 | /* Avoid trying to remove the exit block. */ |
34154e27 | 2746 | b = (c == ENTRY_BLOCK_PTR_FOR_FN (cfun) ? c->next_bb : c); |
2a3e49aa | 2747 | continue; |
e27e52e0 | 2748 | } |
65f34de5 | 2749 | |
fbac255a | 2750 | /* Remove code labels no longer used. */ |
ea091dfd | 2751 | if (single_pred_p (b) |
2752 | && (single_pred_edge (b)->flags & EDGE_FALLTHRU) | |
2753 | && !(single_pred_edge (b)->flags & EDGE_COMPLEX) | |
6d7dc5b9 | 2754 | && LABEL_P (BB_HEAD (b)) |
0d0f5dc5 | 2755 | && !LABEL_PRESERVE_P (BB_HEAD (b)) |
e27e52e0 | 2756 | /* If the previous block ends with a branch to this |
2757 | block, we can't delete the label. Normally this | |
2758 | is a condjump that is yet to be simplified, but | |
2759 | if CASE_DROPS_THRU, this can be a tablejump with | |
2760 | some element going to the same place as the | |
2761 | default (fallthru). */ | |
34154e27 | 2762 | && (single_pred (b) == ENTRY_BLOCK_PTR_FOR_FN (cfun) |
ea091dfd | 2763 | || !JUMP_P (BB_END (single_pred (b))) |
5496dbfc | 2764 | || ! label_is_jump_target_p (BB_HEAD (b), |
ea091dfd | 2765 | BB_END (single_pred (b))))) |
e27e52e0 | 2766 | { |
a2b85e40 | 2767 | delete_insn (BB_HEAD (b)); |
450d042a | 2768 | if (dump_file) |
2769 | fprintf (dump_file, "Deleted label in block %i.\n", | |
b3d6de89 | 2770 | b->index); |
e27e52e0 | 2771 | } |
65f34de5 | 2772 | |
e27e52e0 | 2773 | /* If we fall through an empty block, we can remove it. */ |
8ddad41d | 2774 | if (!(mode & (CLEANUP_CFGLAYOUT | CLEANUP_NO_INSN_DEL)) |
ea091dfd | 2775 | && single_pred_p (b) |
2776 | && (single_pred_edge (b)->flags & EDGE_FALLTHRU) | |
6d7dc5b9 | 2777 | && !LABEL_P (BB_HEAD (b)) |
e27e52e0 | 2778 | && FORWARDER_BLOCK_P (b) |
2779 | /* Note that forwarder_block_p true ensures that | |
2780 | there is a successor for this block. */ | |
ea091dfd | 2781 | && (single_succ_edge (b)->flags & EDGE_FALLTHRU) |
a28770e1 | 2782 | && n_basic_blocks_for_fn (cfun) > NUM_FIXED_BLOCKS + 1) |
e27e52e0 | 2783 | { |
450d042a | 2784 | if (dump_file) |
2785 | fprintf (dump_file, | |
e27e52e0 | 2786 | "Deleting fallthru block %i.\n", |
b3d6de89 | 2787 | b->index); |
e27e52e0 | 2788 | |
34154e27 | 2789 | c = ((b->prev_bb == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
2790 | ? b->next_bb : b->prev_bb); | |
ea091dfd | 2791 | redirect_edge_succ_nodup (single_pred_edge (b), |
2792 | single_succ (b)); | |
5f5d4cd1 | 2793 | delete_basic_block (b); |
e27e52e0 | 2794 | changed = true; |
2795 | b = c; | |
c4d13c5c | 2796 | continue; |
e27e52e0 | 2797 | } |
5cc577b6 | 2798 | |
18b762f0 | 2799 | /* Merge B with its single successor, if any. */ |
ea091dfd | 2800 | if (single_succ_p (b) |
2801 | && (s = single_succ_edge (b)) | |
9d574a94 | 2802 | && !(s->flags & EDGE_COMPLEX) |
34154e27 | 2803 | && (c = s->dest) != EXIT_BLOCK_PTR_FOR_FN (cfun) |
ea091dfd | 2804 | && single_pred_p (c) |
c60fa3a7 | 2805 | && b != c) |
2806 | { | |
2807 | /* When not in cfg_layout mode use code aware of reordering | |
2808 | INSN. This code possibly creates new basic blocks so it | |
2809 | does not fit merge_blocks interface and is kept here in | |
2810 | hope that it will become useless once more of compiler | |
2811 | is transformed to use cfg_layout mode. */ | |
a0c938f0 | 2812 | |
c60fa3a7 | 2813 | if ((mode & CLEANUP_CFGLAYOUT) |
2814 | && can_merge_blocks_p (b, c)) | |
2815 | { | |
2816 | merge_blocks (b, c); | |
2817 | update_forwarder_flag (b); | |
2818 | changed_here = true; | |
2819 | } | |
2820 | else if (!(mode & CLEANUP_CFGLAYOUT) | |
2821 | /* If the jump insn has side effects, | |
2822 | we can't kill the edge. */ | |
6d7dc5b9 | 2823 | && (!JUMP_P (BB_END (b)) |
18f811c9 | 2824 | || (reload_completed |
5496dbfc | 2825 | ? simplejump_p (BB_END (b)) |
902c164d | 2826 | : (onlyjump_p (BB_END (b)) |
2827 | && !tablejump_p (BB_END (b), | |
2828 | NULL, NULL)))) | |
c60fa3a7 | 2829 | && (next = merge_blocks_move (s, b, c, mode))) |
2830 | { | |
2831 | b = next; | |
2832 | changed_here = true; | |
2833 | } | |
9d574a94 | 2834 | } |
e27e52e0 | 2835 | |
2836 | /* Simplify branch over branch. */ | |
c60fa3a7 | 2837 | if ((mode & CLEANUP_EXPENSIVE) |
2838 | && !(mode & CLEANUP_CFGLAYOUT) | |
2839 | && try_simplify_condjump (b)) | |
308f9b79 | 2840 | changed_here = true; |
65f34de5 | 2841 | |
e27e52e0 | 2842 | /* If B has a single outgoing edge, but uses a |
2843 | non-trivial jump instruction without side-effects, we | |
2844 | can either delete the jump entirely, or replace it | |
e5562ab8 | 2845 | with a simple unconditional jump. */ |
ea091dfd | 2846 | if (single_succ_p (b) |
34154e27 | 2847 | && single_succ (b) != EXIT_BLOCK_PTR_FOR_FN (cfun) |
5496dbfc | 2848 | && onlyjump_p (BB_END (b)) |
8f869004 | 2849 | && !CROSSING_JUMP_P (BB_END (b)) |
ea091dfd | 2850 | && try_redirect_by_replacing_jump (single_succ_edge (b), |
2851 | single_succ (b), | |
fa015b9a | 2852 | (mode & CLEANUP_CFGLAYOUT) != 0)) |
e27e52e0 | 2853 | { |
e27e52e0 | 2854 | update_forwarder_flag (b); |
2855 | changed_here = true; | |
2856 | } | |
65f34de5 | 2857 | |
e27e52e0 | 2858 | /* Simplify branch to branch. */ |
2859 | if (try_forward_edges (mode, b)) | |
50f4aeca | 2860 | { |
2861 | update_forwarder_flag (b); | |
2862 | changed_here = true; | |
2863 | } | |
65f34de5 | 2864 | |
e27e52e0 | 2865 | /* Look for shared code between blocks. */ |
2866 | if ((mode & CLEANUP_CROSSJUMP) | |
2867 | && try_crossjump_bb (mode, b)) | |
2868 | changed_here = true; | |
65f34de5 | 2869 | |
bc6adae4 | 2870 | if ((mode & CLEANUP_CROSSJUMP) |
2871 | /* This can lengthen register lifetimes. Do it only after | |
2872 | reload. */ | |
2873 | && reload_completed | |
2874 | && try_head_merge_bb (b)) | |
2875 | changed_here = true; | |
2876 | ||
e27e52e0 | 2877 | /* Don't get confused by the index shift caused by |
2878 | deleting blocks. */ | |
2879 | if (!changed_here) | |
4c26117a | 2880 | b = b->next_bb; |
e27e52e0 | 2881 | else |
2882 | changed = true; | |
2883 | } | |
65f34de5 | 2884 | |
e27e52e0 | 2885 | if ((mode & CLEANUP_CROSSJUMP) |
34154e27 | 2886 | && try_crossjump_bb (mode, EXIT_BLOCK_PTR_FOR_FN (cfun))) |
65f34de5 | 2887 | changed = true; |
65f34de5 | 2888 | |
bc6adae4 | 2889 | if (block_was_dirty) |
2890 | { | |
2891 | /* This should only be set by head-merging. */ | |
2892 | gcc_assert (mode & CLEANUP_CROSSJUMP); | |
2893 | df_analyze (); | |
2894 | } | |
2895 | ||
e27e52e0 | 2896 | if (changed) |
80adc5a6 | 2897 | { |
2898 | /* Edge forwarding in particular can cause hot blocks previously | |
2899 | reached by both hot and cold blocks to become dominated only | |
2900 | by cold blocks. This will cause the verification below to fail, | |
2901 | and lead to now cold code in the hot section. This is not easy | |
2902 | to detect and fix during edge forwarding, and in some cases | |
2903 | is only visible after newly unreachable blocks are deleted, | |
2904 | which will be done in fixup_partitions. */ | |
2905 | fixup_partitions (); | |
2906 | ||
2907 | #ifdef ENABLE_CHECKING | |
2908 | verify_flow_info (); | |
65f34de5 | 2909 | #endif |
80adc5a6 | 2910 | } |
65f34de5 | 2911 | |
e27e52e0 | 2912 | changed_overall |= changed; |
10d3796f | 2913 | first_pass = false; |
e27e52e0 | 2914 | } |
2915 | while (changed); | |
65f34de5 | 2916 | } |
b36d64df | 2917 | |
ed7d889a | 2918 | FOR_ALL_BB_FN (b, cfun) |
4fe5a223 | 2919 | b->flags &= ~(BB_FORWARDER_BLOCK | BB_NONTHREADABLE_BLOCK); |
33dbe4d1 | 2920 | |
65f34de5 | 2921 | return changed_overall; |
2922 | } | |
2923 | \f | |
1e625a2e | 2924 | /* Delete all unreachable basic blocks. */ |
e76f35e8 | 2925 | |
cd0fe062 | 2926 | bool |
4c9e08a4 | 2927 | delete_unreachable_blocks (void) |
65f34de5 | 2928 | { |
65f34de5 | 2929 | bool changed = false; |
9845d120 | 2930 | basic_block b, prev_bb; |
65f34de5 | 2931 | |
2932 | find_unreachable_blocks (); | |
2933 | ||
9845d120 | 2934 | /* When we're in GIMPLE mode and there may be debug insns, we should |
2935 | delete blocks in reverse dominator order, so as to get a chance | |
2936 | to substitute all released DEFs into debug stmts. If we don't | |
2937 | have dominators information, walking blocks backward gets us a | |
2938 | better chance of retaining most debug information than | |
2939 | otherwise. */ | |
4a020a8c | 2940 | if (MAY_HAVE_DEBUG_INSNS && current_ir_type () == IR_GIMPLE |
9845d120 | 2941 | && dom_info_available_p (CDI_DOMINATORS)) |
65f34de5 | 2942 | { |
34154e27 | 2943 | for (b = EXIT_BLOCK_PTR_FOR_FN (cfun)->prev_bb; |
2944 | b != ENTRY_BLOCK_PTR_FOR_FN (cfun); b = prev_bb) | |
9845d120 | 2945 | { |
2946 | prev_bb = b->prev_bb; | |
2947 | ||
2948 | if (!(b->flags & BB_REACHABLE)) | |
2949 | { | |
2950 | /* Speed up the removal of blocks that don't dominate | |
2951 | others. Walking backwards, this should be the common | |
2952 | case. */ | |
2953 | if (!first_dom_son (CDI_DOMINATORS, b)) | |
2954 | delete_basic_block (b); | |
2955 | else | |
2956 | { | |
f1f41a6c | 2957 | vec<basic_block> h |
9845d120 | 2958 | = get_all_dominated_blocks (CDI_DOMINATORS, b); |
2959 | ||
f1f41a6c | 2960 | while (h.length ()) |
9845d120 | 2961 | { |
f1f41a6c | 2962 | b = h.pop (); |
9845d120 | 2963 | |
2964 | prev_bb = b->prev_bb; | |
b3d6de89 | 2965 | |
9845d120 | 2966 | gcc_assert (!(b->flags & BB_REACHABLE)); |
2967 | ||
2968 | delete_basic_block (b); | |
2969 | } | |
2970 | ||
f1f41a6c | 2971 | h.release (); |
9845d120 | 2972 | } |
2973 | ||
2974 | changed = true; | |
2975 | } | |
2976 | } | |
2977 | } | |
2978 | else | |
2979 | { | |
34154e27 | 2980 | for (b = EXIT_BLOCK_PTR_FOR_FN (cfun)->prev_bb; |
2981 | b != ENTRY_BLOCK_PTR_FOR_FN (cfun); b = prev_bb) | |
8f8dcce4 | 2982 | { |
9845d120 | 2983 | prev_bb = b->prev_bb; |
2984 | ||
2985 | if (!(b->flags & BB_REACHABLE)) | |
2986 | { | |
2987 | delete_basic_block (b); | |
2988 | changed = true; | |
2989 | } | |
8f8dcce4 | 2990 | } |
65f34de5 | 2991 | } |
2992 | ||
2993 | if (changed) | |
2994 | tidy_fallthru_edges (); | |
2995 | return changed; | |
2996 | } | |
3072d30e | 2997 | |
2998 | /* Delete any jump tables never referenced. We can't delete them at the | |
c38b28e7 | 2999 | time of removing tablejump insn as they are referenced by the preceding |
3000 | insns computing the destination, so we delay deleting and garbagecollect | |
3001 | them once life information is computed. */ | |
3072d30e | 3002 | void |
3003 | delete_dead_jumptables (void) | |
3004 | { | |
3005 | basic_block bb; | |
3006 | ||
c38b28e7 | 3007 | /* A dead jump table does not belong to any basic block. Scan insns |
3008 | between two adjacent basic blocks. */ | |
fc00614f | 3009 | FOR_EACH_BB_FN (bb, cfun) |
3072d30e | 3010 | { |
c093ac49 | 3011 | rtx_insn *insn, *next; |
c38b28e7 | 3012 | |
3013 | for (insn = NEXT_INSN (BB_END (bb)); | |
3014 | insn && !NOTE_INSN_BASIC_BLOCK_P (insn); | |
3015 | insn = next) | |
0b3f0f44 | 3016 | { |
c38b28e7 | 3017 | next = NEXT_INSN (insn); |
3018 | if (LABEL_P (insn) | |
3019 | && LABEL_NUSES (insn) == LABEL_PRESERVE_P (insn) | |
3020 | && JUMP_TABLE_DATA_P (next)) | |
3021 | { | |
c093ac49 | 3022 | rtx_insn *label = insn, *jump = next; |
c38b28e7 | 3023 | |
3024 | if (dump_file) | |
3025 | fprintf (dump_file, "Dead jumptable %i removed\n", | |
3026 | INSN_UID (insn)); | |
3027 | ||
3028 | next = NEXT_INSN (next); | |
3029 | delete_insn (jump); | |
3030 | delete_insn (label); | |
3031 | } | |
3072d30e | 3032 | } |
3033 | } | |
3034 | } | |
3035 | ||
65f34de5 | 3036 | \f |
3037 | /* Tidy the CFG by deleting unreachable code and whatnot. */ | |
3038 | ||
3039 | bool | |
4c9e08a4 | 3040 | cleanup_cfg (int mode) |
65f34de5 | 3041 | { |
65f34de5 | 3042 | bool changed = false; |
3043 | ||
30641a08 | 3044 | /* Set the cfglayout mode flag here. We could update all the callers |
3045 | but that is just inconvenient, especially given that we eventually | |
3046 | want to have cfglayout mode as the default. */ | |
3047 | if (current_ir_type () == IR_RTL_CFGLAYOUT) | |
3048 | mode |= CLEANUP_CFGLAYOUT; | |
3049 | ||
65f34de5 | 3050 | timevar_push (TV_CLEANUP_CFG); |
fb20d6fa | 3051 | if (delete_unreachable_blocks ()) |
3052 | { | |
3053 | changed = true; | |
3054 | /* We've possibly created trivially dead code. Cleanup it right | |
d716ce75 | 3055 | now to introduce more opportunities for try_optimize_cfg. */ |
3072d30e | 3056 | if (!(mode & (CLEANUP_NO_INSN_DEL)) |
fb20d6fa | 3057 | && !reload_completed) |
d4473c84 | 3058 | delete_trivially_dead_insns (get_insns (), max_reg_num ()); |
fb20d6fa | 3059 | } |
3c0a32c9 | 3060 | |
3061 | compact_blocks (); | |
3062 | ||
1ae2ffa7 | 3063 | /* To tail-merge blocks ending in the same noreturn function (e.g. |
3064 | a call to abort) we have to insert fake edges to exit. Do this | |
3065 | here once. The fake edges do not interfere with any other CFG | |
3066 | cleanups. */ | |
3067 | if (mode & CLEANUP_CROSSJUMP) | |
3068 | add_noreturn_fake_exit_edges (); | |
3069 | ||
4ff06051 | 3070 | if (!dbg_cnt (cfg_cleanup)) |
3071 | return changed; | |
3072 | ||
fb20d6fa | 3073 | while (try_optimize_cfg (mode)) |
3074 | { | |
3075 | delete_unreachable_blocks (), changed = true; | |
1ae2ffa7 | 3076 | if (!(mode & CLEANUP_NO_INSN_DEL)) |
fb20d6fa | 3077 | { |
1ae2ffa7 | 3078 | /* Try to remove some trivially dead insns when doing an expensive |
3079 | cleanup. But delete_trivially_dead_insns doesn't work after | |
3080 | reload (it only handles pseudos) and run_fast_dce is too costly | |
3081 | to run in every iteration. | |
3082 | ||
3083 | For effective cross jumping, we really want to run a fast DCE to | |
3084 | clean up any dead conditions, or they get in the way of performing | |
3085 | useful tail merges. | |
3086 | ||
3087 | Other transformations in cleanup_cfg are not so sensitive to dead | |
3088 | code, so delete_trivially_dead_insns or even doing nothing at all | |
3089 | is good enough. */ | |
3090 | if ((mode & CLEANUP_EXPENSIVE) && !reload_completed | |
3091 | && !delete_trivially_dead_insns (get_insns (), max_reg_num ())) | |
fb20d6fa | 3092 | break; |
bc6adae4 | 3093 | if ((mode & CLEANUP_CROSSJUMP) && crossjumps_occured) |
bc27bb3b | 3094 | run_fast_dce (); |
fb20d6fa | 3095 | } |
3096 | else | |
3097 | break; | |
fb20d6fa | 3098 | } |
65f34de5 | 3099 | |
1ae2ffa7 | 3100 | if (mode & CLEANUP_CROSSJUMP) |
3101 | remove_fake_exit_edges (); | |
3102 | ||
c38b28e7 | 3103 | /* Don't call delete_dead_jumptables in cfglayout mode, because |
3104 | that function assumes that jump tables are in the insns stream. | |
3105 | But we also don't _have_ to delete dead jumptables in cfglayout | |
3106 | mode because we shouldn't even be looking at things that are | |
3107 | not in a basic block. Dead jumptables are cleaned up when | |
3108 | going out of cfglayout mode. */ | |
3109 | if (!(mode & CLEANUP_CFGLAYOUT)) | |
3072d30e | 3110 | delete_dead_jumptables (); |
3111 | ||
79f958cb | 3112 | /* ??? We probably do this way too often. */ |
3113 | if (current_loops | |
3114 | && (changed | |
3115 | || (mode & CLEANUP_CFG_CHANGED))) | |
3116 | { | |
79f958cb | 3117 | timevar_push (TV_REPAIR_LOOPS); |
3118 | /* The above doesn't preserve dominance info if available. */ | |
3119 | gcc_assert (!dom_info_available_p (CDI_DOMINATORS)); | |
3120 | calculate_dominance_info (CDI_DOMINATORS); | |
022d4ccc | 3121 | fix_loop_structure (NULL); |
79f958cb | 3122 | free_dominance_info (CDI_DOMINATORS); |
3123 | timevar_pop (TV_REPAIR_LOOPS); | |
3124 | } | |
3125 | ||
65f34de5 | 3126 | timevar_pop (TV_CLEANUP_CFG); |
3127 | ||
65f34de5 | 3128 | return changed; |
3129 | } | |
77fce4cd | 3130 | \f |
cbe8bda8 | 3131 | namespace { |
3132 | ||
3133 | const pass_data pass_data_jump = | |
76cdbc6d | 3134 | { |
cbe8bda8 | 3135 | RTL_PASS, /* type */ |
3136 | "jump", /* name */ | |
3137 | OPTGROUP_NONE, /* optinfo_flags */ | |
cbe8bda8 | 3138 | TV_JUMP, /* tv_id */ |
3139 | 0, /* properties_required */ | |
3140 | 0, /* properties_provided */ | |
3141 | 0, /* properties_destroyed */ | |
3142 | 0, /* todo_flags_start */ | |
8b88439e | 3143 | 0, /* todo_flags_finish */ |
76cdbc6d | 3144 | }; |
cbe8bda8 | 3145 | |
3146 | class pass_jump : public rtl_opt_pass | |
3147 | { | |
3148 | public: | |
9af5ce0c | 3149 | pass_jump (gcc::context *ctxt) |
3150 | : rtl_opt_pass (pass_data_jump, ctxt) | |
cbe8bda8 | 3151 | {} |
3152 | ||
3153 | /* opt_pass methods: */ | |
65b0537f | 3154 | virtual unsigned int execute (function *); |
cbe8bda8 | 3155 | |
3156 | }; // class pass_jump | |
3157 | ||
65b0537f | 3158 | unsigned int |
3159 | pass_jump::execute (function *) | |
3160 | { | |
3161 | delete_trivially_dead_insns (get_insns (), max_reg_num ()); | |
3162 | if (dump_file) | |
3163 | dump_flow_info (dump_file, dump_flags); | |
3164 | cleanup_cfg ((optimize ? CLEANUP_EXPENSIVE : 0) | |
3165 | | (flag_thread_jumps ? CLEANUP_THREADING : 0)); | |
3166 | return 0; | |
3167 | } | |
3168 | ||
cbe8bda8 | 3169 | } // anon namespace |
3170 | ||
3171 | rtl_opt_pass * | |
3172 | make_pass_jump (gcc::context *ctxt) | |
3173 | { | |
3174 | return new pass_jump (ctxt); | |
3175 | } | |
76cdbc6d | 3176 | \f |
cbe8bda8 | 3177 | namespace { |
3178 | ||
3179 | const pass_data pass_data_jump2 = | |
77fce4cd | 3180 | { |
cbe8bda8 | 3181 | RTL_PASS, /* type */ |
3182 | "jump2", /* name */ | |
3183 | OPTGROUP_NONE, /* optinfo_flags */ | |
cbe8bda8 | 3184 | TV_JUMP, /* tv_id */ |
3185 | 0, /* properties_required */ | |
3186 | 0, /* properties_provided */ | |
3187 | 0, /* properties_destroyed */ | |
3188 | 0, /* todo_flags_start */ | |
8b88439e | 3189 | 0, /* todo_flags_finish */ |
77fce4cd | 3190 | }; |
cbe8bda8 | 3191 | |
3192 | class pass_jump2 : public rtl_opt_pass | |
3193 | { | |
3194 | public: | |
9af5ce0c | 3195 | pass_jump2 (gcc::context *ctxt) |
3196 | : rtl_opt_pass (pass_data_jump2, ctxt) | |
cbe8bda8 | 3197 | {} |
3198 | ||
3199 | /* opt_pass methods: */ | |
65b0537f | 3200 | virtual unsigned int execute (function *) |
3201 | { | |
3202 | cleanup_cfg (flag_crossjumping ? CLEANUP_CROSSJUMP : 0); | |
3203 | return 0; | |
3204 | } | |
cbe8bda8 | 3205 | |
3206 | }; // class pass_jump2 | |
3207 | ||
3208 | } // anon namespace | |
3209 | ||
3210 | rtl_opt_pass * | |
3211 | make_pass_jump2 (gcc::context *ctxt) | |
3212 | { | |
3213 | return new pass_jump2 (ctxt); | |
3214 | } |