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c9e93168 TV |
1 | /* Tail merging for gimple. |
2 | Copyright (C) 2011 Free Software Foundation, Inc. | |
3 | Contributed by Tom de Vries (tom@codesourcery.com) | |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 3, or (at your option) | |
10 | any later version. | |
11 | ||
12 | GCC is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with GCC; see the file COPYING3. If not see | |
19 | <http://www.gnu.org/licenses/>. */ | |
20 | ||
21 | /* Pass overview. | |
22 | ||
23 | ||
24 | MOTIVATIONAL EXAMPLE | |
25 | ||
26 | gimple representation of gcc/testsuite/gcc.dg/pr43864.c at | |
27 | ||
28 | hprofStartupp (charD.1 * outputFileNameD.2600, charD.1 * ctxD.2601) | |
29 | { | |
30 | struct FILED.1638 * fpD.2605; | |
31 | charD.1 fileNameD.2604[1000]; | |
32 | intD.0 D.3915; | |
33 | const charD.1 * restrict outputFileName.0D.3914; | |
34 | ||
35 | # BLOCK 2 freq:10000 | |
36 | # PRED: ENTRY [100.0%] (fallthru,exec) | |
37 | # PT = nonlocal { D.3926 } (restr) | |
38 | outputFileName.0D.3914_3 | |
39 | = (const charD.1 * restrict) outputFileNameD.2600_2(D); | |
40 | # .MEMD.3923_13 = VDEF <.MEMD.3923_12(D)> | |
41 | # USE = nonlocal null { fileNameD.2604 D.3926 } (restr) | |
42 | # CLB = nonlocal null { fileNameD.2604 D.3926 } (restr) | |
43 | sprintfD.759 (&fileNameD.2604, outputFileName.0D.3914_3); | |
44 | # .MEMD.3923_14 = VDEF <.MEMD.3923_13> | |
45 | # USE = nonlocal null { fileNameD.2604 D.3926 } (restr) | |
46 | # CLB = nonlocal null { fileNameD.2604 D.3926 } (restr) | |
47 | D.3915_4 = accessD.2606 (&fileNameD.2604, 1); | |
48 | if (D.3915_4 == 0) | |
49 | goto <bb 3>; | |
50 | else | |
51 | goto <bb 4>; | |
52 | # SUCC: 3 [10.0%] (true,exec) 4 [90.0%] (false,exec) | |
53 | ||
54 | # BLOCK 3 freq:1000 | |
55 | # PRED: 2 [10.0%] (true,exec) | |
56 | # .MEMD.3923_15 = VDEF <.MEMD.3923_14> | |
57 | # USE = nonlocal null { fileNameD.2604 D.3926 } (restr) | |
58 | # CLB = nonlocal null { fileNameD.2604 D.3926 } (restr) | |
59 | freeD.898 (ctxD.2601_5(D)); | |
60 | goto <bb 7>; | |
61 | # SUCC: 7 [100.0%] (fallthru,exec) | |
62 | ||
63 | # BLOCK 4 freq:9000 | |
64 | # PRED: 2 [90.0%] (false,exec) | |
65 | # .MEMD.3923_16 = VDEF <.MEMD.3923_14> | |
66 | # PT = nonlocal escaped | |
67 | # USE = nonlocal null { fileNameD.2604 D.3926 } (restr) | |
68 | # CLB = nonlocal null { fileNameD.2604 D.3926 } (restr) | |
69 | fpD.2605_8 = fopenD.1805 (&fileNameD.2604[0], 0B); | |
70 | if (fpD.2605_8 == 0B) | |
71 | goto <bb 5>; | |
72 | else | |
73 | goto <bb 6>; | |
74 | # SUCC: 5 [1.9%] (true,exec) 6 [98.1%] (false,exec) | |
75 | ||
76 | # BLOCK 5 freq:173 | |
77 | # PRED: 4 [1.9%] (true,exec) | |
78 | # .MEMD.3923_17 = VDEF <.MEMD.3923_16> | |
79 | # USE = nonlocal null { fileNameD.2604 D.3926 } (restr) | |
80 | # CLB = nonlocal null { fileNameD.2604 D.3926 } (restr) | |
81 | freeD.898 (ctxD.2601_5(D)); | |
82 | goto <bb 7>; | |
83 | # SUCC: 7 [100.0%] (fallthru,exec) | |
84 | ||
85 | # BLOCK 6 freq:8827 | |
86 | # PRED: 4 [98.1%] (false,exec) | |
87 | # .MEMD.3923_18 = VDEF <.MEMD.3923_16> | |
88 | # USE = nonlocal null { fileNameD.2604 D.3926 } (restr) | |
89 | # CLB = nonlocal null { fileNameD.2604 D.3926 } (restr) | |
90 | fooD.2599 (outputFileNameD.2600_2(D), fpD.2605_8); | |
91 | # SUCC: 7 [100.0%] (fallthru,exec) | |
92 | ||
93 | # BLOCK 7 freq:10000 | |
94 | # PRED: 3 [100.0%] (fallthru,exec) 5 [100.0%] (fallthru,exec) | |
95 | 6 [100.0%] (fallthru,exec) | |
96 | # PT = nonlocal null | |
97 | ||
98 | # ctxD.2601_1 = PHI <0B(3), 0B(5), ctxD.2601_5(D)(6)> | |
99 | # .MEMD.3923_11 = PHI <.MEMD.3923_15(3), .MEMD.3923_17(5), | |
100 | .MEMD.3923_18(6)> | |
101 | # VUSE <.MEMD.3923_11> | |
102 | return ctxD.2601_1; | |
103 | # SUCC: EXIT [100.0%] | |
104 | } | |
105 | ||
106 | bb 3 and bb 5 can be merged. The blocks have different predecessors, but the | |
107 | same successors, and the same operations. | |
108 | ||
109 | ||
110 | CONTEXT | |
111 | ||
112 | A technique called tail merging (or cross jumping) can fix the example | |
113 | above. For a block, we look for common code at the end (the tail) of the | |
114 | predecessor blocks, and insert jumps from one block to the other. | |
115 | The example is a special case for tail merging, in that 2 whole blocks | |
116 | can be merged, rather than just the end parts of it. | |
117 | We currently only focus on whole block merging, so in that sense | |
118 | calling this pass tail merge is a bit of a misnomer. | |
119 | ||
120 | We distinguish 2 kinds of situations in which blocks can be merged: | |
121 | - same operations, same predecessors. The successor edges coming from one | |
122 | block are redirected to come from the other block. | |
123 | - same operations, same successors. The predecessor edges entering one block | |
124 | are redirected to enter the other block. Note that this operation might | |
125 | involve introducing phi operations. | |
126 | ||
127 | For efficient implementation, we would like to value numbers the blocks, and | |
128 | have a comparison operator that tells us whether the blocks are equal. | |
129 | Besides being runtime efficient, block value numbering should also abstract | |
130 | from irrelevant differences in order of operations, much like normal value | |
131 | numbering abstracts from irrelevant order of operations. | |
132 | ||
133 | For the first situation (same_operations, same predecessors), normal value | |
134 | numbering fits well. We can calculate a block value number based on the | |
135 | value numbers of the defs and vdefs. | |
136 | ||
137 | For the second situation (same operations, same successors), this approach | |
138 | doesn't work so well. We can illustrate this using the example. The calls | |
139 | to free use different vdefs: MEMD.3923_16 and MEMD.3923_14, and these will | |
140 | remain different in value numbering, since they represent different memory | |
141 | states. So the resulting vdefs of the frees will be different in value | |
142 | numbering, so the block value numbers will be different. | |
143 | ||
144 | The reason why we call the blocks equal is not because they define the same | |
145 | values, but because uses in the blocks use (possibly different) defs in the | |
146 | same way. To be able to detect this efficiently, we need to do some kind of | |
147 | reverse value numbering, meaning number the uses rather than the defs, and | |
148 | calculate a block value number based on the value number of the uses. | |
149 | Ideally, a block comparison operator will also indicate which phis are needed | |
150 | to merge the blocks. | |
151 | ||
152 | For the moment, we don't do block value numbering, but we do insn-by-insn | |
153 | matching, using scc value numbers to match operations with results, and | |
154 | structural comparison otherwise, while ignoring vop mismatches. | |
155 | ||
156 | ||
157 | IMPLEMENTATION | |
158 | ||
159 | 1. The pass first determines all groups of blocks with the same successor | |
160 | blocks. | |
161 | 2. Within each group, it tries to determine clusters of equal basic blocks. | |
162 | 3. The clusters are applied. | |
163 | 4. The same successor groups are updated. | |
164 | 5. This process is repeated from 2 onwards, until no more changes. | |
165 | ||
166 | ||
167 | LIMITATIONS/TODO | |
168 | ||
169 | - block only | |
170 | - handles only 'same operations, same successors'. | |
171 | It handles same predecessors as a special subcase though. | |
172 | - does not implement the reverse value numbering and block value numbering. | |
173 | - improve memory allocation: use garbage collected memory, obstacks, | |
174 | allocpools where appropriate. | |
175 | - no insertion of gimple_reg phis, We only introduce vop-phis. | |
176 | - handle blocks with gimple_reg phi_nodes. | |
177 | ||
178 | ||
179 | SWITCHES | |
180 | ||
181 | - ftree-tail-merge. On at -O2. We may have to enable it only at -Os. */ | |
182 | ||
183 | #include "config.h" | |
184 | #include "system.h" | |
185 | #include "coretypes.h" | |
186 | #include "tm.h" | |
187 | #include "tree.h" | |
188 | #include "tm_p.h" | |
189 | #include "basic-block.h" | |
190 | #include "output.h" | |
191 | #include "flags.h" | |
192 | #include "function.h" | |
193 | #include "tree-flow.h" | |
194 | #include "timevar.h" | |
195 | #include "bitmap.h" | |
196 | #include "tree-ssa-alias.h" | |
197 | #include "params.h" | |
198 | #include "tree-pretty-print.h" | |
199 | #include "hashtab.h" | |
200 | #include "gimple-pretty-print.h" | |
201 | #include "tree-ssa-sccvn.h" | |
202 | #include "tree-dump.h" | |
203 | ||
204 | /* Describes a group of bbs with the same successors. The successor bbs are | |
205 | cached in succs, and the successor edge flags are cached in succ_flags. | |
206 | If a bb has the EDGE_TRUE/VALSE_VALUE flags swapped compared to succ_flags, | |
207 | it's marked in inverse. | |
208 | Additionally, the hash value for the struct is cached in hashval, and | |
209 | in_worklist indicates whether it's currently part of worklist. */ | |
210 | ||
211 | struct same_succ_def | |
212 | { | |
213 | /* The bbs that have the same successor bbs. */ | |
214 | bitmap bbs; | |
215 | /* The successor bbs. */ | |
216 | bitmap succs; | |
217 | /* Indicates whether the EDGE_TRUE/FALSE_VALUEs of succ_flags are swapped for | |
218 | bb. */ | |
219 | bitmap inverse; | |
220 | /* The edge flags for each of the successor bbs. */ | |
221 | VEC (int, heap) *succ_flags; | |
222 | /* Indicates whether the struct is currently in the worklist. */ | |
223 | bool in_worklist; | |
224 | /* The hash value of the struct. */ | |
225 | hashval_t hashval; | |
226 | }; | |
227 | typedef struct same_succ_def *same_succ; | |
228 | typedef const struct same_succ_def *const_same_succ; | |
229 | ||
230 | /* A group of bbs where 1 bb from bbs can replace the other bbs. */ | |
231 | ||
232 | struct bb_cluster_def | |
233 | { | |
234 | /* The bbs in the cluster. */ | |
235 | bitmap bbs; | |
236 | /* The preds of the bbs in the cluster. */ | |
237 | bitmap preds; | |
238 | /* Index in all_clusters vector. */ | |
239 | int index; | |
240 | /* The bb to replace the cluster with. */ | |
241 | basic_block rep_bb; | |
242 | }; | |
243 | typedef struct bb_cluster_def *bb_cluster; | |
244 | typedef const struct bb_cluster_def *const_bb_cluster; | |
245 | ||
246 | /* Per bb-info. */ | |
247 | ||
248 | struct aux_bb_info | |
249 | { | |
250 | /* The number of non-debug statements in the bb. */ | |
251 | int size; | |
252 | /* The same_succ that this bb is a member of. */ | |
253 | same_succ bb_same_succ; | |
254 | /* The cluster that this bb is a member of. */ | |
255 | bb_cluster cluster; | |
256 | /* The vop state at the exit of a bb. This is shortlived data, used to | |
257 | communicate data between update_block_by and update_vuses. */ | |
258 | tree vop_at_exit; | |
259 | /* The bb that either contains or is dominated by the dependencies of the | |
260 | bb. */ | |
261 | basic_block dep_bb; | |
262 | }; | |
263 | ||
264 | /* Macros to access the fields of struct aux_bb_info. */ | |
265 | ||
266 | #define BB_SIZE(bb) (((struct aux_bb_info *)bb->aux)->size) | |
267 | #define BB_SAME_SUCC(bb) (((struct aux_bb_info *)bb->aux)->bb_same_succ) | |
268 | #define BB_CLUSTER(bb) (((struct aux_bb_info *)bb->aux)->cluster) | |
269 | #define BB_VOP_AT_EXIT(bb) (((struct aux_bb_info *)bb->aux)->vop_at_exit) | |
270 | #define BB_DEP_BB(bb) (((struct aux_bb_info *)bb->aux)->dep_bb) | |
271 | ||
272 | /* VAL1 and VAL2 are either: | |
273 | - uses in BB1 and BB2, or | |
274 | - phi alternatives for BB1 and BB2. | |
275 | Return true if the uses have the same gvn value. */ | |
276 | ||
277 | static bool | |
278 | gvn_uses_equal (tree val1, tree val2) | |
279 | { | |
280 | gcc_checking_assert (val1 != NULL_TREE && val2 != NULL_TREE); | |
281 | ||
282 | if (val1 == val2) | |
283 | return true; | |
284 | ||
285 | if (vn_valueize (val1) != vn_valueize (val2)) | |
286 | return false; | |
287 | ||
288 | return ((TREE_CODE (val1) == SSA_NAME || CONSTANT_CLASS_P (val1)) | |
289 | && (TREE_CODE (val2) == SSA_NAME || CONSTANT_CLASS_P (val2))); | |
290 | } | |
291 | ||
292 | /* Prints E to FILE. */ | |
293 | ||
294 | static void | |
295 | same_succ_print (FILE *file, const same_succ e) | |
296 | { | |
297 | unsigned int i; | |
298 | bitmap_print (file, e->bbs, "bbs:", "\n"); | |
299 | bitmap_print (file, e->succs, "succs:", "\n"); | |
300 | bitmap_print (file, e->inverse, "inverse:", "\n"); | |
301 | fprintf (file, "flags:"); | |
302 | for (i = 0; i < VEC_length (int, e->succ_flags); ++i) | |
303 | fprintf (file, " %x", VEC_index (int, e->succ_flags, i)); | |
304 | fprintf (file, "\n"); | |
305 | } | |
306 | ||
307 | /* Prints same_succ VE to VFILE. */ | |
308 | ||
309 | static int | |
310 | same_succ_print_traverse (void **ve, void *vfile) | |
311 | { | |
312 | const same_succ e = *((const same_succ *)ve); | |
313 | FILE *file = ((FILE*)vfile); | |
314 | same_succ_print (file, e); | |
315 | return 1; | |
316 | } | |
317 | ||
318 | /* Update BB_DEP_BB (USE_BB), given a use of VAL in USE_BB. */ | |
319 | ||
320 | static void | |
321 | update_dep_bb (basic_block use_bb, tree val) | |
322 | { | |
323 | basic_block dep_bb; | |
324 | ||
325 | /* Not a dep. */ | |
326 | if (TREE_CODE (val) != SSA_NAME) | |
327 | return; | |
328 | ||
329 | /* Skip use of global def. */ | |
330 | if (SSA_NAME_IS_DEFAULT_DEF (val)) | |
331 | return; | |
332 | ||
333 | /* Skip use of local def. */ | |
334 | dep_bb = gimple_bb (SSA_NAME_DEF_STMT (val)); | |
335 | if (dep_bb == use_bb) | |
336 | return; | |
337 | ||
338 | if (BB_DEP_BB (use_bb) == NULL | |
339 | || dominated_by_p (CDI_DOMINATORS, dep_bb, BB_DEP_BB (use_bb))) | |
340 | BB_DEP_BB (use_bb) = dep_bb; | |
341 | } | |
342 | ||
343 | /* Update BB_DEP_BB, given the dependencies in STMT. */ | |
344 | ||
345 | static void | |
346 | stmt_update_dep_bb (gimple stmt) | |
347 | { | |
348 | ssa_op_iter iter; | |
349 | use_operand_p use; | |
350 | ||
351 | FOR_EACH_SSA_USE_OPERAND (use, stmt, iter, SSA_OP_USE) | |
352 | update_dep_bb (gimple_bb (stmt), USE_FROM_PTR (use)); | |
353 | } | |
354 | ||
355 | /* Returns whether VAL is used in the same bb as in which it is defined, or | |
356 | in the phi of a successor bb. */ | |
357 | ||
358 | static bool | |
359 | local_def (tree val) | |
360 | { | |
361 | gimple stmt, def_stmt; | |
362 | basic_block bb, def_bb; | |
363 | imm_use_iterator iter; | |
364 | bool res; | |
365 | ||
366 | if (TREE_CODE (val) != SSA_NAME) | |
367 | return false; | |
368 | def_stmt = SSA_NAME_DEF_STMT (val); | |
369 | def_bb = gimple_bb (def_stmt); | |
370 | ||
371 | res = true; | |
372 | FOR_EACH_IMM_USE_STMT (stmt, iter, val) | |
373 | { | |
374 | bb = gimple_bb (stmt); | |
375 | if (bb == def_bb) | |
376 | continue; | |
377 | if (gimple_code (stmt) == GIMPLE_PHI | |
378 | && find_edge (def_bb, bb)) | |
379 | continue; | |
380 | res = false; | |
381 | BREAK_FROM_IMM_USE_STMT (iter); | |
382 | } | |
383 | return res; | |
384 | } | |
385 | ||
386 | /* Calculates hash value for same_succ VE. */ | |
387 | ||
388 | static hashval_t | |
389 | same_succ_hash (const void *ve) | |
390 | { | |
391 | const_same_succ e = (const_same_succ)ve; | |
392 | hashval_t hashval = bitmap_hash (e->succs); | |
393 | int flags; | |
394 | unsigned int i; | |
395 | unsigned int first = bitmap_first_set_bit (e->bbs); | |
396 | basic_block bb = BASIC_BLOCK (first); | |
397 | int size = 0; | |
398 | gimple_stmt_iterator gsi; | |
399 | gimple stmt; | |
400 | tree arg; | |
401 | unsigned int s; | |
402 | bitmap_iterator bs; | |
403 | ||
404 | for (gsi = gsi_start_nondebug_bb (bb); | |
405 | !gsi_end_p (gsi); gsi_next_nondebug (&gsi)) | |
406 | { | |
407 | stmt = gsi_stmt (gsi); | |
408 | stmt_update_dep_bb (stmt); | |
409 | if (is_gimple_assign (stmt) && local_def (gimple_get_lhs (stmt)) | |
410 | && !gimple_has_side_effects (stmt)) | |
411 | continue; | |
412 | size++; | |
413 | ||
414 | hashval = iterative_hash_hashval_t (gimple_code (stmt), hashval); | |
415 | if (is_gimple_assign (stmt)) | |
416 | hashval = iterative_hash_hashval_t (gimple_assign_rhs_code (stmt), | |
417 | hashval); | |
418 | if (!is_gimple_call (stmt)) | |
419 | continue; | |
420 | if (gimple_call_internal_p (stmt)) | |
421 | hashval = iterative_hash_hashval_t | |
422 | ((hashval_t) gimple_call_internal_fn (stmt), hashval); | |
423 | else | |
424 | hashval = iterative_hash_expr (gimple_call_fn (stmt), hashval); | |
425 | for (i = 0; i < gimple_call_num_args (stmt); i++) | |
426 | { | |
427 | arg = gimple_call_arg (stmt, i); | |
428 | arg = vn_valueize (arg); | |
429 | hashval = iterative_hash_expr (arg, hashval); | |
430 | } | |
431 | } | |
432 | ||
433 | hashval = iterative_hash_hashval_t (size, hashval); | |
434 | BB_SIZE (bb) = size; | |
435 | ||
436 | for (i = 0; i < VEC_length (int, e->succ_flags); ++i) | |
437 | { | |
438 | flags = VEC_index (int, e->succ_flags, i); | |
439 | flags = flags & ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE); | |
440 | hashval = iterative_hash_hashval_t (flags, hashval); | |
441 | } | |
442 | ||
443 | EXECUTE_IF_SET_IN_BITMAP (e->succs, 0, s, bs) | |
444 | { | |
445 | int n = find_edge (bb, BASIC_BLOCK (s))->dest_idx; | |
446 | for (gsi = gsi_start_phis (BASIC_BLOCK (s)); !gsi_end_p (gsi); | |
447 | gsi_next (&gsi)) | |
448 | { | |
449 | gimple phi = gsi_stmt (gsi); | |
450 | tree lhs = gimple_phi_result (phi); | |
451 | tree val = gimple_phi_arg_def (phi, n); | |
452 | ||
453 | if (!is_gimple_reg (lhs)) | |
454 | continue; | |
455 | update_dep_bb (bb, val); | |
456 | } | |
457 | } | |
458 | ||
459 | return hashval; | |
460 | } | |
461 | ||
462 | /* Returns true if E1 and E2 have 2 successors, and if the successor flags | |
463 | are inverse for the EDGE_TRUE_VALUE and EDGE_FALSE_VALUE flags, and equal for | |
464 | the other edge flags. */ | |
465 | ||
466 | static bool | |
467 | inverse_flags (const_same_succ e1, const_same_succ e2) | |
468 | { | |
469 | int f1a, f1b, f2a, f2b; | |
470 | int mask = ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE); | |
471 | ||
472 | if (VEC_length (int, e1->succ_flags) != 2) | |
473 | return false; | |
474 | ||
475 | f1a = VEC_index (int, e1->succ_flags, 0); | |
476 | f1b = VEC_index (int, e1->succ_flags, 1); | |
477 | f2a = VEC_index (int, e2->succ_flags, 0); | |
478 | f2b = VEC_index (int, e2->succ_flags, 1); | |
479 | ||
480 | if (f1a == f2a && f1b == f2b) | |
481 | return false; | |
482 | ||
483 | return (f1a & mask) == (f2a & mask) && (f1b & mask) == (f2b & mask); | |
484 | } | |
485 | ||
486 | /* Compares SAME_SUCCs VE1 and VE2. */ | |
487 | ||
488 | static int | |
489 | same_succ_equal (const void *ve1, const void *ve2) | |
490 | { | |
491 | const_same_succ e1 = (const_same_succ)ve1; | |
492 | const_same_succ e2 = (const_same_succ)ve2; | |
493 | unsigned int i, first1, first2; | |
494 | gimple_stmt_iterator gsi1, gsi2; | |
495 | gimple s1, s2; | |
496 | basic_block bb1, bb2; | |
497 | ||
498 | if (e1->hashval != e2->hashval) | |
499 | return 0; | |
500 | ||
501 | if (VEC_length (int, e1->succ_flags) != VEC_length (int, e2->succ_flags)) | |
502 | return 0; | |
503 | ||
504 | if (!bitmap_equal_p (e1->succs, e2->succs)) | |
505 | return 0; | |
506 | ||
507 | if (!inverse_flags (e1, e2)) | |
508 | { | |
509 | for (i = 0; i < VEC_length (int, e1->succ_flags); ++i) | |
510 | if (VEC_index (int, e1->succ_flags, i) | |
511 | != VEC_index (int, e1->succ_flags, i)) | |
512 | return 0; | |
513 | } | |
514 | ||
515 | first1 = bitmap_first_set_bit (e1->bbs); | |
516 | first2 = bitmap_first_set_bit (e2->bbs); | |
517 | ||
518 | bb1 = BASIC_BLOCK (first1); | |
519 | bb2 = BASIC_BLOCK (first2); | |
520 | ||
521 | if (BB_SIZE (bb1) != BB_SIZE (bb2)) | |
522 | return 0; | |
523 | ||
524 | gsi1 = gsi_start_nondebug_bb (bb1); | |
525 | gsi2 = gsi_start_nondebug_bb (bb2); | |
526 | while (!(gsi_end_p (gsi1) || gsi_end_p (gsi2))) | |
527 | { | |
528 | s1 = gsi_stmt (gsi1); | |
529 | s2 = gsi_stmt (gsi2); | |
530 | if (gimple_code (s1) != gimple_code (s2)) | |
531 | return 0; | |
532 | if (is_gimple_call (s1) && !gimple_call_same_target_p (s1, s2)) | |
533 | return 0; | |
534 | gsi_next_nondebug (&gsi1); | |
535 | gsi_next_nondebug (&gsi2); | |
536 | } | |
537 | ||
538 | return 1; | |
539 | } | |
540 | ||
541 | /* Alloc and init a new SAME_SUCC. */ | |
542 | ||
543 | static same_succ | |
544 | same_succ_alloc (void) | |
545 | { | |
546 | same_succ same = XNEW (struct same_succ_def); | |
547 | ||
548 | same->bbs = BITMAP_ALLOC (NULL); | |
549 | same->succs = BITMAP_ALLOC (NULL); | |
550 | same->inverse = BITMAP_ALLOC (NULL); | |
551 | same->succ_flags = VEC_alloc (int, heap, 10); | |
552 | same->in_worklist = false; | |
553 | ||
554 | return same; | |
555 | } | |
556 | ||
557 | /* Delete same_succ VE. */ | |
558 | ||
559 | static void | |
560 | same_succ_delete (void *ve) | |
561 | { | |
562 | same_succ e = (same_succ)ve; | |
563 | ||
564 | BITMAP_FREE (e->bbs); | |
565 | BITMAP_FREE (e->succs); | |
566 | BITMAP_FREE (e->inverse); | |
567 | VEC_free (int, heap, e->succ_flags); | |
568 | ||
569 | XDELETE (ve); | |
570 | } | |
571 | ||
572 | /* Reset same_succ SAME. */ | |
573 | ||
574 | static void | |
575 | same_succ_reset (same_succ same) | |
576 | { | |
577 | bitmap_clear (same->bbs); | |
578 | bitmap_clear (same->succs); | |
579 | bitmap_clear (same->inverse); | |
580 | VEC_truncate (int, same->succ_flags, 0); | |
581 | } | |
582 | ||
583 | /* Hash table with all same_succ entries. */ | |
584 | ||
585 | static htab_t same_succ_htab; | |
586 | ||
587 | /* Array that is used to store the edge flags for a successor. */ | |
588 | ||
589 | static int *same_succ_edge_flags; | |
590 | ||
591 | /* Bitmap that is used to mark bbs that are recently deleted. */ | |
592 | ||
593 | static bitmap deleted_bbs; | |
594 | ||
595 | /* Bitmap that is used to mark predecessors of bbs that are | |
596 | deleted. */ | |
597 | ||
598 | static bitmap deleted_bb_preds; | |
599 | ||
600 | /* Prints same_succ_htab to stderr. */ | |
601 | ||
602 | extern void debug_same_succ (void); | |
603 | DEBUG_FUNCTION void | |
604 | debug_same_succ ( void) | |
605 | { | |
606 | htab_traverse (same_succ_htab, same_succ_print_traverse, stderr); | |
607 | } | |
608 | ||
609 | DEF_VEC_P (same_succ); | |
610 | DEF_VEC_ALLOC_P (same_succ, heap); | |
611 | ||
612 | /* Vector of bbs to process. */ | |
613 | ||
614 | static VEC (same_succ, heap) *worklist; | |
615 | ||
616 | /* Prints worklist to FILE. */ | |
617 | ||
618 | static void | |
619 | print_worklist (FILE *file) | |
620 | { | |
621 | unsigned int i; | |
622 | for (i = 0; i < VEC_length (same_succ, worklist); ++i) | |
623 | same_succ_print (file, VEC_index (same_succ, worklist, i)); | |
624 | } | |
625 | ||
626 | /* Adds SAME to worklist. */ | |
627 | ||
628 | static void | |
629 | add_to_worklist (same_succ same) | |
630 | { | |
631 | if (same->in_worklist) | |
632 | return; | |
633 | ||
634 | if (bitmap_count_bits (same->bbs) < 2) | |
635 | return; | |
636 | ||
637 | same->in_worklist = true; | |
638 | VEC_safe_push (same_succ, heap, worklist, same); | |
639 | } | |
640 | ||
641 | /* Add BB to same_succ_htab. */ | |
642 | ||
643 | static void | |
644 | find_same_succ_bb (basic_block bb, same_succ *same_p) | |
645 | { | |
646 | unsigned int j; | |
647 | bitmap_iterator bj; | |
648 | same_succ same = *same_p; | |
649 | same_succ *slot; | |
650 | edge_iterator ei; | |
651 | edge e; | |
652 | ||
653 | if (bb == NULL) | |
654 | return; | |
655 | bitmap_set_bit (same->bbs, bb->index); | |
656 | FOR_EACH_EDGE (e, ei, bb->succs) | |
657 | { | |
658 | int index = e->dest->index; | |
659 | bitmap_set_bit (same->succs, index); | |
660 | same_succ_edge_flags[index] = e->flags; | |
661 | } | |
662 | EXECUTE_IF_SET_IN_BITMAP (same->succs, 0, j, bj) | |
663 | VEC_safe_push (int, heap, same->succ_flags, same_succ_edge_flags[j]); | |
664 | ||
665 | same->hashval = same_succ_hash (same); | |
666 | ||
667 | slot = (same_succ *) htab_find_slot_with_hash (same_succ_htab, same, | |
668 | same->hashval, INSERT); | |
669 | if (*slot == NULL) | |
670 | { | |
671 | *slot = same; | |
672 | BB_SAME_SUCC (bb) = same; | |
673 | add_to_worklist (same); | |
674 | *same_p = NULL; | |
675 | } | |
676 | else | |
677 | { | |
678 | bitmap_set_bit ((*slot)->bbs, bb->index); | |
679 | BB_SAME_SUCC (bb) = *slot; | |
680 | add_to_worklist (*slot); | |
681 | if (inverse_flags (same, *slot)) | |
682 | bitmap_set_bit ((*slot)->inverse, bb->index); | |
683 | same_succ_reset (same); | |
684 | } | |
685 | } | |
686 | ||
687 | /* Find bbs with same successors. */ | |
688 | ||
689 | static void | |
690 | find_same_succ (void) | |
691 | { | |
692 | same_succ same = same_succ_alloc (); | |
693 | basic_block bb; | |
694 | ||
695 | FOR_EACH_BB (bb) | |
696 | { | |
697 | find_same_succ_bb (bb, &same); | |
698 | if (same == NULL) | |
699 | same = same_succ_alloc (); | |
700 | } | |
701 | ||
702 | same_succ_delete (same); | |
703 | } | |
704 | ||
705 | /* Initializes worklist administration. */ | |
706 | ||
707 | static void | |
708 | init_worklist (void) | |
709 | { | |
710 | alloc_aux_for_blocks (sizeof (struct aux_bb_info)); | |
711 | same_succ_htab | |
712 | = htab_create (n_basic_blocks, same_succ_hash, same_succ_equal, | |
713 | same_succ_delete); | |
714 | same_succ_edge_flags = XCNEWVEC (int, last_basic_block); | |
715 | deleted_bbs = BITMAP_ALLOC (NULL); | |
716 | deleted_bb_preds = BITMAP_ALLOC (NULL); | |
717 | worklist = VEC_alloc (same_succ, heap, n_basic_blocks); | |
718 | find_same_succ (); | |
719 | ||
720 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
721 | { | |
722 | fprintf (dump_file, "initial worklist:\n"); | |
723 | print_worklist (dump_file); | |
724 | } | |
725 | } | |
726 | ||
727 | /* Deletes worklist administration. */ | |
728 | ||
729 | static void | |
730 | delete_worklist (void) | |
731 | { | |
732 | free_aux_for_blocks (); | |
733 | htab_delete (same_succ_htab); | |
734 | same_succ_htab = NULL; | |
735 | XDELETEVEC (same_succ_edge_flags); | |
736 | same_succ_edge_flags = NULL; | |
737 | BITMAP_FREE (deleted_bbs); | |
738 | BITMAP_FREE (deleted_bb_preds); | |
739 | VEC_free (same_succ, heap, worklist); | |
740 | } | |
741 | ||
742 | /* Mark BB as deleted, and mark its predecessors. */ | |
743 | ||
744 | static void | |
643400b8 | 745 | mark_basic_block_deleted (basic_block bb) |
c9e93168 TV |
746 | { |
747 | edge e; | |
748 | edge_iterator ei; | |
749 | ||
750 | bitmap_set_bit (deleted_bbs, bb->index); | |
751 | ||
752 | FOR_EACH_EDGE (e, ei, bb->preds) | |
753 | bitmap_set_bit (deleted_bb_preds, e->src->index); | |
754 | } | |
755 | ||
4cbdcd40 TV |
756 | /* Removes BB from its corresponding same_succ. */ |
757 | ||
758 | static void | |
759 | same_succ_flush_bb (basic_block bb) | |
760 | { | |
761 | same_succ same = BB_SAME_SUCC (bb); | |
762 | BB_SAME_SUCC (bb) = NULL; | |
763 | if (bitmap_single_bit_set_p (same->bbs)) | |
764 | htab_remove_elt_with_hash (same_succ_htab, same, same->hashval); | |
765 | else | |
766 | bitmap_clear_bit (same->bbs, bb->index); | |
767 | } | |
768 | ||
c9e93168 TV |
769 | /* Removes all bbs in BBS from their corresponding same_succ. */ |
770 | ||
771 | static void | |
772 | same_succ_flush_bbs (bitmap bbs) | |
773 | { | |
774 | unsigned int i; | |
775 | bitmap_iterator bi; | |
776 | ||
777 | EXECUTE_IF_SET_IN_BITMAP (bbs, 0, i, bi) | |
4cbdcd40 | 778 | same_succ_flush_bb (BASIC_BLOCK (i)); |
c9e93168 TV |
779 | } |
780 | ||
266fbb79 TV |
781 | /* Release the last vdef in BB, either normal or phi result. */ |
782 | ||
783 | static void | |
784 | release_last_vdef (basic_block bb) | |
785 | { | |
786 | gimple_stmt_iterator i; | |
787 | ||
788 | for (i = gsi_last_bb (bb); !gsi_end_p (i); gsi_prev_nondebug (&i)) | |
789 | { | |
790 | gimple stmt = gsi_stmt (i); | |
791 | if (gimple_vdef (stmt) == NULL_TREE) | |
792 | continue; | |
793 | ||
794 | mark_virtual_operand_for_renaming (gimple_vdef (stmt)); | |
795 | return; | |
796 | } | |
797 | ||
798 | for (i = gsi_start_phis (bb); !gsi_end_p (i); gsi_next (&i)) | |
799 | { | |
800 | gimple phi = gsi_stmt (i); | |
801 | tree res = gimple_phi_result (phi); | |
802 | ||
803 | if (is_gimple_reg (res)) | |
804 | continue; | |
805 | ||
806 | mark_virtual_phi_result_for_renaming (phi); | |
807 | return; | |
808 | } | |
809 | ||
810 | } | |
811 | ||
c9e93168 TV |
812 | /* For deleted_bb_preds, find bbs with same successors. */ |
813 | ||
814 | static void | |
815 | update_worklist (void) | |
816 | { | |
817 | unsigned int i; | |
818 | bitmap_iterator bi; | |
819 | basic_block bb; | |
820 | same_succ same; | |
821 | ||
643400b8 TV |
822 | bitmap_and_compl_into (deleted_bb_preds, deleted_bbs); |
823 | bitmap_clear (deleted_bbs); | |
824 | ||
c9e93168 TV |
825 | bitmap_clear_bit (deleted_bb_preds, ENTRY_BLOCK); |
826 | same_succ_flush_bbs (deleted_bb_preds); | |
827 | ||
828 | same = same_succ_alloc (); | |
829 | EXECUTE_IF_SET_IN_BITMAP (deleted_bb_preds, 0, i, bi) | |
830 | { | |
831 | bb = BASIC_BLOCK (i); | |
832 | gcc_assert (bb != NULL); | |
833 | find_same_succ_bb (bb, &same); | |
834 | if (same == NULL) | |
835 | same = same_succ_alloc (); | |
836 | } | |
837 | same_succ_delete (same); | |
838 | bitmap_clear (deleted_bb_preds); | |
839 | } | |
840 | ||
841 | /* Prints cluster C to FILE. */ | |
842 | ||
843 | static void | |
844 | print_cluster (FILE *file, bb_cluster c) | |
845 | { | |
846 | if (c == NULL) | |
847 | return; | |
848 | bitmap_print (file, c->bbs, "bbs:", "\n"); | |
849 | bitmap_print (file, c->preds, "preds:", "\n"); | |
850 | } | |
851 | ||
852 | /* Prints cluster C to stderr. */ | |
853 | ||
854 | extern void debug_cluster (bb_cluster); | |
855 | DEBUG_FUNCTION void | |
856 | debug_cluster (bb_cluster c) | |
857 | { | |
858 | print_cluster (stderr, c); | |
859 | } | |
860 | ||
861 | /* Update C->rep_bb, given that BB is added to the cluster. */ | |
862 | ||
863 | static void | |
864 | update_rep_bb (bb_cluster c, basic_block bb) | |
865 | { | |
866 | /* Initial. */ | |
867 | if (c->rep_bb == NULL) | |
868 | { | |
869 | c->rep_bb = bb; | |
870 | return; | |
871 | } | |
872 | ||
873 | /* Current needs no deps, keep it. */ | |
874 | if (BB_DEP_BB (c->rep_bb) == NULL) | |
875 | return; | |
876 | ||
877 | /* Bb needs no deps, change rep_bb. */ | |
878 | if (BB_DEP_BB (bb) == NULL) | |
879 | { | |
880 | c->rep_bb = bb; | |
881 | return; | |
882 | } | |
883 | ||
884 | /* Bb needs last deps earlier than current, change rep_bb. A potential | |
885 | problem with this, is that the first deps might also be earlier, which | |
886 | would mean we prefer longer lifetimes for the deps. To be able to check | |
887 | for this, we would have to trace BB_FIRST_DEP_BB as well, besides | |
888 | BB_DEP_BB, which is really BB_LAST_DEP_BB. | |
889 | The benefit of choosing the bb with last deps earlier, is that it can | |
890 | potentially be used as replacement for more bbs. */ | |
891 | if (dominated_by_p (CDI_DOMINATORS, BB_DEP_BB (c->rep_bb), BB_DEP_BB (bb))) | |
892 | c->rep_bb = bb; | |
893 | } | |
894 | ||
895 | /* Add BB to cluster C. Sets BB in C->bbs, and preds of BB in C->preds. */ | |
896 | ||
897 | static void | |
898 | add_bb_to_cluster (bb_cluster c, basic_block bb) | |
899 | { | |
900 | edge e; | |
901 | edge_iterator ei; | |
902 | ||
903 | bitmap_set_bit (c->bbs, bb->index); | |
904 | ||
905 | FOR_EACH_EDGE (e, ei, bb->preds) | |
906 | bitmap_set_bit (c->preds, e->src->index); | |
907 | ||
908 | update_rep_bb (c, bb); | |
909 | } | |
910 | ||
911 | /* Allocate and init new cluster. */ | |
912 | ||
913 | static bb_cluster | |
914 | new_cluster (void) | |
915 | { | |
916 | bb_cluster c; | |
917 | c = XCNEW (struct bb_cluster_def); | |
918 | c->bbs = BITMAP_ALLOC (NULL); | |
919 | c->preds = BITMAP_ALLOC (NULL); | |
920 | c->rep_bb = NULL; | |
921 | return c; | |
922 | } | |
923 | ||
924 | /* Delete clusters. */ | |
925 | ||
926 | static void | |
927 | delete_cluster (bb_cluster c) | |
928 | { | |
929 | if (c == NULL) | |
930 | return; | |
931 | BITMAP_FREE (c->bbs); | |
932 | BITMAP_FREE (c->preds); | |
933 | XDELETE (c); | |
934 | } | |
935 | ||
936 | DEF_VEC_P (bb_cluster); | |
937 | DEF_VEC_ALLOC_P (bb_cluster, heap); | |
938 | ||
939 | /* Array that contains all clusters. */ | |
940 | ||
941 | static VEC (bb_cluster, heap) *all_clusters; | |
942 | ||
943 | /* Allocate all cluster vectors. */ | |
944 | ||
945 | static void | |
946 | alloc_cluster_vectors (void) | |
947 | { | |
948 | all_clusters = VEC_alloc (bb_cluster, heap, n_basic_blocks); | |
949 | } | |
950 | ||
951 | /* Reset all cluster vectors. */ | |
952 | ||
953 | static void | |
954 | reset_cluster_vectors (void) | |
955 | { | |
956 | unsigned int i; | |
957 | basic_block bb; | |
958 | for (i = 0; i < VEC_length (bb_cluster, all_clusters); ++i) | |
959 | delete_cluster (VEC_index (bb_cluster, all_clusters, i)); | |
960 | VEC_truncate (bb_cluster, all_clusters, 0); | |
961 | FOR_EACH_BB (bb) | |
962 | BB_CLUSTER (bb) = NULL; | |
963 | } | |
964 | ||
965 | /* Delete all cluster vectors. */ | |
966 | ||
967 | static void | |
968 | delete_cluster_vectors (void) | |
969 | { | |
970 | unsigned int i; | |
971 | for (i = 0; i < VEC_length (bb_cluster, all_clusters); ++i) | |
972 | delete_cluster (VEC_index (bb_cluster, all_clusters, i)); | |
973 | VEC_free (bb_cluster, heap, all_clusters); | |
974 | } | |
975 | ||
976 | /* Merge cluster C2 into C1. */ | |
977 | ||
978 | static void | |
979 | merge_clusters (bb_cluster c1, bb_cluster c2) | |
980 | { | |
981 | bitmap_ior_into (c1->bbs, c2->bbs); | |
982 | bitmap_ior_into (c1->preds, c2->preds); | |
983 | } | |
984 | ||
985 | /* Register equivalence of BB1 and BB2 (members of cluster C). Store c in | |
986 | all_clusters, or merge c with existing cluster. */ | |
987 | ||
988 | static void | |
989 | set_cluster (basic_block bb1, basic_block bb2) | |
990 | { | |
991 | basic_block merge_bb, other_bb; | |
992 | bb_cluster merge, old, c; | |
993 | ||
994 | if (BB_CLUSTER (bb1) == NULL && BB_CLUSTER (bb2) == NULL) | |
995 | { | |
996 | c = new_cluster (); | |
997 | add_bb_to_cluster (c, bb1); | |
998 | add_bb_to_cluster (c, bb2); | |
999 | BB_CLUSTER (bb1) = c; | |
1000 | BB_CLUSTER (bb2) = c; | |
1001 | c->index = VEC_length (bb_cluster, all_clusters); | |
1002 | VEC_safe_push (bb_cluster, heap, all_clusters, c); | |
1003 | } | |
1004 | else if (BB_CLUSTER (bb1) == NULL || BB_CLUSTER (bb2) == NULL) | |
1005 | { | |
1006 | merge_bb = BB_CLUSTER (bb1) == NULL ? bb2 : bb1; | |
1007 | other_bb = BB_CLUSTER (bb1) == NULL ? bb1 : bb2; | |
1008 | merge = BB_CLUSTER (merge_bb); | |
1009 | add_bb_to_cluster (merge, other_bb); | |
1010 | BB_CLUSTER (other_bb) = merge; | |
1011 | } | |
1012 | else if (BB_CLUSTER (bb1) != BB_CLUSTER (bb2)) | |
1013 | { | |
1014 | unsigned int i; | |
1015 | bitmap_iterator bi; | |
1016 | ||
1017 | old = BB_CLUSTER (bb2); | |
1018 | merge = BB_CLUSTER (bb1); | |
1019 | merge_clusters (merge, old); | |
1020 | EXECUTE_IF_SET_IN_BITMAP (old->bbs, 0, i, bi) | |
1021 | BB_CLUSTER (BASIC_BLOCK (i)) = merge; | |
1022 | VEC_replace (bb_cluster, all_clusters, old->index, NULL); | |
1023 | update_rep_bb (merge, old->rep_bb); | |
1024 | delete_cluster (old); | |
1025 | } | |
1026 | else | |
1027 | gcc_unreachable (); | |
1028 | } | |
1029 | ||
1030 | /* Return true if gimple statements S1 and S2 are equal. Gimple_bb (s1) and | |
1031 | gimple_bb (s2) are members of SAME_SUCC. */ | |
1032 | ||
1033 | static bool | |
1034 | gimple_equal_p (same_succ same_succ, gimple s1, gimple s2) | |
1035 | { | |
1036 | unsigned int i; | |
1037 | tree lhs1, lhs2; | |
1038 | basic_block bb1 = gimple_bb (s1), bb2 = gimple_bb (s2); | |
1039 | tree t1, t2; | |
1040 | bool equal, inv_cond; | |
1041 | enum tree_code code1, code2; | |
1042 | ||
1043 | if (gimple_code (s1) != gimple_code (s2)) | |
1044 | return false; | |
1045 | ||
1046 | switch (gimple_code (s1)) | |
1047 | { | |
1048 | case GIMPLE_CALL: | |
1049 | if (gimple_call_num_args (s1) != gimple_call_num_args (s2)) | |
1050 | return false; | |
1051 | if (!gimple_call_same_target_p (s1, s2)) | |
1052 | return false; | |
1053 | ||
feca8f5a TR |
1054 | /* Eventually, we'll significantly complicate the CFG by adding |
1055 | back edges to properly model the effects of transaction restart. | |
1056 | For the bulk of optimization this does not matter, but what we | |
1057 | cannot recover from is tail merging blocks between two separate | |
1058 | transactions. Avoid that by making commit not match. */ | |
1059 | if (gimple_call_builtin_p (s1, BUILT_IN_TM_COMMIT)) | |
1060 | return false; | |
1061 | ||
c9e93168 TV |
1062 | equal = true; |
1063 | for (i = 0; i < gimple_call_num_args (s1); ++i) | |
1064 | { | |
1065 | t1 = gimple_call_arg (s1, i); | |
1066 | t2 = gimple_call_arg (s2, i); | |
1067 | if (operand_equal_p (t1, t2, 0)) | |
1068 | continue; | |
1069 | if (gvn_uses_equal (t1, t2)) | |
1070 | continue; | |
1071 | equal = false; | |
1072 | break; | |
1073 | } | |
1074 | if (equal) | |
1075 | return true; | |
1076 | ||
1077 | lhs1 = gimple_get_lhs (s1); | |
1078 | lhs2 = gimple_get_lhs (s2); | |
1079 | return (lhs1 != NULL_TREE && lhs2 != NULL_TREE | |
1080 | && TREE_CODE (lhs1) == SSA_NAME && TREE_CODE (lhs2) == SSA_NAME | |
1081 | && vn_valueize (lhs1) == vn_valueize (lhs2)); | |
1082 | ||
1083 | case GIMPLE_ASSIGN: | |
1084 | lhs1 = gimple_get_lhs (s1); | |
1085 | lhs2 = gimple_get_lhs (s2); | |
1086 | return (TREE_CODE (lhs1) == SSA_NAME | |
1087 | && TREE_CODE (lhs2) == SSA_NAME | |
1088 | && vn_valueize (lhs1) == vn_valueize (lhs2)); | |
1089 | ||
1090 | case GIMPLE_COND: | |
1091 | t1 = gimple_cond_lhs (s1); | |
1092 | t2 = gimple_cond_lhs (s2); | |
1093 | if (!operand_equal_p (t1, t2, 0) | |
1094 | && !gvn_uses_equal (t1, t2)) | |
1095 | return false; | |
1096 | ||
1097 | t1 = gimple_cond_rhs (s1); | |
1098 | t2 = gimple_cond_rhs (s2); | |
1099 | if (!operand_equal_p (t1, t2, 0) | |
1100 | && !gvn_uses_equal (t1, t2)) | |
1101 | return false; | |
1102 | ||
1103 | code1 = gimple_expr_code (s1); | |
1104 | code2 = gimple_expr_code (s2); | |
1105 | inv_cond = (bitmap_bit_p (same_succ->inverse, bb1->index) | |
1106 | != bitmap_bit_p (same_succ->inverse, bb2->index)); | |
1107 | if (inv_cond) | |
1108 | { | |
1109 | bool honor_nans | |
1110 | = HONOR_NANS (TYPE_MODE (TREE_TYPE (gimple_cond_lhs (s1)))); | |
1111 | code2 = invert_tree_comparison (code2, honor_nans); | |
1112 | } | |
1113 | return code1 == code2; | |
1114 | ||
1115 | default: | |
1116 | return false; | |
1117 | } | |
1118 | } | |
1119 | ||
1120 | /* Let GSI skip backwards over local defs. */ | |
1121 | ||
1122 | static void | |
1123 | gsi_advance_bw_nondebug_nonlocal (gimple_stmt_iterator *gsi) | |
1124 | { | |
1125 | gimple stmt; | |
1126 | ||
1127 | while (true) | |
1128 | { | |
1129 | if (gsi_end_p (*gsi)) | |
1130 | return; | |
1131 | stmt = gsi_stmt (*gsi); | |
1132 | if (!(is_gimple_assign (stmt) && local_def (gimple_get_lhs (stmt)) | |
1133 | && !gimple_has_side_effects (stmt))) | |
1134 | return; | |
1135 | gsi_prev_nondebug (gsi); | |
1136 | } | |
1137 | } | |
1138 | ||
1139 | /* Determines whether BB1 and BB2 (members of same_succ) are duplicates. If so, | |
1140 | clusters them. */ | |
1141 | ||
1142 | static void | |
1143 | find_duplicate (same_succ same_succ, basic_block bb1, basic_block bb2) | |
1144 | { | |
1145 | gimple_stmt_iterator gsi1 = gsi_last_nondebug_bb (bb1); | |
1146 | gimple_stmt_iterator gsi2 = gsi_last_nondebug_bb (bb2); | |
1147 | ||
1148 | gsi_advance_bw_nondebug_nonlocal (&gsi1); | |
1149 | gsi_advance_bw_nondebug_nonlocal (&gsi2); | |
1150 | ||
1151 | while (!gsi_end_p (gsi1) && !gsi_end_p (gsi2)) | |
1152 | { | |
1153 | if (!gimple_equal_p (same_succ, gsi_stmt (gsi1), gsi_stmt (gsi2))) | |
1154 | return; | |
1155 | ||
1156 | gsi_prev_nondebug (&gsi1); | |
1157 | gsi_prev_nondebug (&gsi2); | |
1158 | gsi_advance_bw_nondebug_nonlocal (&gsi1); | |
1159 | gsi_advance_bw_nondebug_nonlocal (&gsi2); | |
1160 | } | |
1161 | ||
1162 | if (!(gsi_end_p (gsi1) && gsi_end_p (gsi2))) | |
1163 | return; | |
1164 | ||
1165 | if (dump_file) | |
1166 | fprintf (dump_file, "find_duplicates: <bb %d> duplicate of <bb %d>\n", | |
1167 | bb1->index, bb2->index); | |
1168 | ||
1169 | set_cluster (bb1, bb2); | |
1170 | } | |
1171 | ||
1172 | /* Returns whether for all phis in DEST the phi alternatives for E1 and | |
1173 | E2 are equal. */ | |
1174 | ||
1175 | static bool | |
1176 | same_phi_alternatives_1 (basic_block dest, edge e1, edge e2) | |
1177 | { | |
1178 | int n1 = e1->dest_idx, n2 = e2->dest_idx; | |
1179 | gimple_stmt_iterator gsi; | |
1180 | ||
1181 | for (gsi = gsi_start_phis (dest); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1182 | { | |
1183 | gimple phi = gsi_stmt (gsi); | |
1184 | tree lhs = gimple_phi_result (phi); | |
1185 | tree val1 = gimple_phi_arg_def (phi, n1); | |
1186 | tree val2 = gimple_phi_arg_def (phi, n2); | |
1187 | ||
1188 | if (!is_gimple_reg (lhs)) | |
1189 | continue; | |
1190 | ||
1191 | if (operand_equal_for_phi_arg_p (val1, val2)) | |
1192 | continue; | |
1193 | if (gvn_uses_equal (val1, val2)) | |
1194 | continue; | |
1195 | ||
1196 | return false; | |
1197 | } | |
1198 | ||
1199 | return true; | |
1200 | } | |
1201 | ||
1202 | /* Returns whether for all successors of BB1 and BB2 (members of SAME_SUCC), the | |
1203 | phi alternatives for BB1 and BB2 are equal. */ | |
1204 | ||
1205 | static bool | |
1206 | same_phi_alternatives (same_succ same_succ, basic_block bb1, basic_block bb2) | |
1207 | { | |
1208 | unsigned int s; | |
1209 | bitmap_iterator bs; | |
1210 | edge e1, e2; | |
1211 | basic_block succ; | |
1212 | ||
1213 | EXECUTE_IF_SET_IN_BITMAP (same_succ->succs, 0, s, bs) | |
1214 | { | |
1215 | succ = BASIC_BLOCK (s); | |
1216 | e1 = find_edge (bb1, succ); | |
1217 | e2 = find_edge (bb2, succ); | |
1218 | if (e1->flags & EDGE_COMPLEX | |
1219 | || e2->flags & EDGE_COMPLEX) | |
1220 | return false; | |
1221 | ||
1222 | /* For all phis in bb, the phi alternatives for e1 and e2 need to have | |
1223 | the same value. */ | |
1224 | if (!same_phi_alternatives_1 (succ, e1, e2)) | |
1225 | return false; | |
1226 | } | |
1227 | ||
1228 | return true; | |
1229 | } | |
1230 | ||
1231 | /* Return true if BB has non-vop phis. */ | |
1232 | ||
1233 | static bool | |
1234 | bb_has_non_vop_phi (basic_block bb) | |
1235 | { | |
1236 | gimple_seq phis = phi_nodes (bb); | |
1237 | gimple phi; | |
1238 | ||
1239 | if (phis == NULL) | |
1240 | return false; | |
1241 | ||
1242 | if (!gimple_seq_singleton_p (phis)) | |
1243 | return true; | |
1244 | ||
1245 | phi = gimple_seq_first_stmt (phis); | |
1246 | return is_gimple_reg (gimple_phi_result (phi)); | |
1247 | } | |
1248 | ||
1249 | /* Returns true if redirecting the incoming edges of FROM to TO maintains the | |
1250 | invariant that uses in FROM are dominates by their defs. */ | |
1251 | ||
1252 | static bool | |
1253 | deps_ok_for_redirect_from_bb_to_bb (basic_block from, basic_block to) | |
1254 | { | |
1255 | basic_block cd, dep_bb = BB_DEP_BB (to); | |
1256 | edge_iterator ei; | |
1257 | edge e; | |
1258 | bitmap from_preds = BITMAP_ALLOC (NULL); | |
1259 | ||
1260 | if (dep_bb == NULL) | |
1261 | return true; | |
1262 | ||
1263 | FOR_EACH_EDGE (e, ei, from->preds) | |
1264 | bitmap_set_bit (from_preds, e->src->index); | |
1265 | cd = nearest_common_dominator_for_set (CDI_DOMINATORS, from_preds); | |
1266 | BITMAP_FREE (from_preds); | |
1267 | ||
1268 | return dominated_by_p (CDI_DOMINATORS, dep_bb, cd); | |
1269 | } | |
1270 | ||
1271 | /* Returns true if replacing BB1 (or its replacement bb) by BB2 (or its | |
1272 | replacement bb) and vice versa maintains the invariant that uses in the | |
1273 | replacement are dominates by their defs. */ | |
1274 | ||
1275 | static bool | |
1276 | deps_ok_for_redirect (basic_block bb1, basic_block bb2) | |
1277 | { | |
1278 | if (BB_CLUSTER (bb1) != NULL) | |
1279 | bb1 = BB_CLUSTER (bb1)->rep_bb; | |
1280 | ||
1281 | if (BB_CLUSTER (bb2) != NULL) | |
1282 | bb2 = BB_CLUSTER (bb2)->rep_bb; | |
1283 | ||
1284 | return (deps_ok_for_redirect_from_bb_to_bb (bb1, bb2) | |
1285 | && deps_ok_for_redirect_from_bb_to_bb (bb2, bb1)); | |
1286 | } | |
1287 | ||
1288 | /* Within SAME_SUCC->bbs, find clusters of bbs which can be merged. */ | |
1289 | ||
1290 | static void | |
1291 | find_clusters_1 (same_succ same_succ) | |
1292 | { | |
1293 | basic_block bb1, bb2; | |
1294 | unsigned int i, j; | |
1295 | bitmap_iterator bi, bj; | |
1296 | int nr_comparisons; | |
1297 | int max_comparisons = PARAM_VALUE (PARAM_MAX_TAIL_MERGE_COMPARISONS); | |
1298 | ||
1299 | EXECUTE_IF_SET_IN_BITMAP (same_succ->bbs, 0, i, bi) | |
1300 | { | |
1301 | bb1 = BASIC_BLOCK (i); | |
1302 | ||
1303 | /* TODO: handle blocks with phi-nodes. We'll have to find corresponding | |
1304 | phi-nodes in bb1 and bb2, with the same alternatives for the same | |
1305 | preds. */ | |
1306 | if (bb_has_non_vop_phi (bb1)) | |
1307 | continue; | |
1308 | ||
1309 | nr_comparisons = 0; | |
1310 | EXECUTE_IF_SET_IN_BITMAP (same_succ->bbs, i + 1, j, bj) | |
1311 | { | |
1312 | bb2 = BASIC_BLOCK (j); | |
1313 | ||
1314 | if (bb_has_non_vop_phi (bb2)) | |
1315 | continue; | |
1316 | ||
1317 | if (BB_CLUSTER (bb1) != NULL && BB_CLUSTER (bb1) == BB_CLUSTER (bb2)) | |
1318 | continue; | |
1319 | ||
1320 | /* Limit quadratic behaviour. */ | |
1321 | nr_comparisons++; | |
1322 | if (nr_comparisons > max_comparisons) | |
1323 | break; | |
1324 | ||
1325 | /* This is a conservative dependency check. We could test more | |
1326 | precise for allowed replacement direction. */ | |
1327 | if (!deps_ok_for_redirect (bb1, bb2)) | |
1328 | continue; | |
1329 | ||
1330 | if (!(same_phi_alternatives (same_succ, bb1, bb2))) | |
1331 | continue; | |
1332 | ||
1333 | find_duplicate (same_succ, bb1, bb2); | |
1334 | } | |
1335 | } | |
1336 | } | |
1337 | ||
1338 | /* Find clusters of bbs which can be merged. */ | |
1339 | ||
1340 | static void | |
1341 | find_clusters (void) | |
1342 | { | |
1343 | same_succ same; | |
1344 | ||
1345 | while (!VEC_empty (same_succ, worklist)) | |
1346 | { | |
1347 | same = VEC_pop (same_succ, worklist); | |
1348 | same->in_worklist = false; | |
1349 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1350 | { | |
1351 | fprintf (dump_file, "processing worklist entry\n"); | |
1352 | same_succ_print (dump_file, same); | |
1353 | } | |
1354 | find_clusters_1 (same); | |
1355 | } | |
1356 | } | |
1357 | ||
c9e93168 TV |
1358 | /* Returns the vop phi of BB, if any. */ |
1359 | ||
1360 | static gimple | |
1361 | vop_phi (basic_block bb) | |
1362 | { | |
1363 | gimple stmt; | |
1364 | gimple_stmt_iterator gsi; | |
1365 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1366 | { | |
1367 | stmt = gsi_stmt (gsi); | |
1368 | if (is_gimple_reg (gimple_phi_result (stmt))) | |
1369 | continue; | |
1370 | return stmt; | |
1371 | } | |
1372 | return NULL; | |
1373 | } | |
1374 | ||
643400b8 | 1375 | /* Redirect all edges from BB1 to BB2, removes BB1 and marks it as removed. */ |
c9e93168 TV |
1376 | |
1377 | static void | |
643400b8 | 1378 | replace_block_by (basic_block bb1, basic_block bb2) |
c9e93168 TV |
1379 | { |
1380 | edge pred_edge; | |
1381 | unsigned int i; | |
643400b8 | 1382 | gimple bb2_phi; |
40f73edd | 1383 | |
643400b8 | 1384 | bb2_phi = vop_phi (bb2); |
c9e93168 | 1385 | |
643400b8 TV |
1386 | /* Mark the basic block as deleted. */ |
1387 | mark_basic_block_deleted (bb1); | |
c9e93168 TV |
1388 | |
1389 | /* Redirect the incoming edges of bb1 to bb2. */ | |
1390 | for (i = EDGE_COUNT (bb1->preds); i > 0 ; --i) | |
1391 | { | |
1392 | pred_edge = EDGE_PRED (bb1, i - 1); | |
1393 | pred_edge = redirect_edge_and_branch (pred_edge, bb2); | |
1394 | gcc_assert (pred_edge != NULL); | |
643400b8 TV |
1395 | |
1396 | if (bb2_phi == NULL) | |
1397 | continue; | |
1398 | ||
1399 | /* The phi might have run out of capacity when the redirect added an | |
1400 | argument, which means it could have been replaced. Refresh it. */ | |
1401 | bb2_phi = vop_phi (bb2); | |
1402 | ||
1403 | add_phi_arg (bb2_phi, SSA_NAME_VAR (gimple_phi_result (bb2_phi)), | |
1404 | pred_edge, UNKNOWN_LOCATION); | |
c9e93168 TV |
1405 | } |
1406 | ||
fa405d7b TV |
1407 | bb2->frequency += bb1->frequency; |
1408 | if (bb2->frequency > BB_FREQ_MAX) | |
1409 | bb2->frequency = BB_FREQ_MAX; | |
1410 | bb1->frequency = 0; | |
1411 | ||
a31895d7 | 1412 | /* Do updates that use bb1, before deleting bb1. */ |
643400b8 | 1413 | release_last_vdef (bb1); |
a31895d7 TV |
1414 | same_succ_flush_bb (bb1); |
1415 | ||
643400b8 | 1416 | delete_basic_block (bb1); |
c9e93168 TV |
1417 | } |
1418 | ||
1419 | /* Bbs for which update_debug_stmt need to be called. */ | |
1420 | ||
1421 | static bitmap update_bbs; | |
1422 | ||
1423 | /* For each cluster in all_clusters, merge all cluster->bbs. Returns | |
643400b8 | 1424 | number of bbs removed. */ |
c9e93168 TV |
1425 | |
1426 | static int | |
643400b8 | 1427 | apply_clusters (void) |
c9e93168 TV |
1428 | { |
1429 | basic_block bb1, bb2; | |
1430 | bb_cluster c; | |
1431 | unsigned int i, j; | |
1432 | bitmap_iterator bj; | |
1433 | int nr_bbs_removed = 0; | |
1434 | ||
1435 | for (i = 0; i < VEC_length (bb_cluster, all_clusters); ++i) | |
1436 | { | |
1437 | c = VEC_index (bb_cluster, all_clusters, i); | |
1438 | if (c == NULL) | |
1439 | continue; | |
1440 | ||
1441 | bb2 = c->rep_bb; | |
1442 | bitmap_set_bit (update_bbs, bb2->index); | |
1443 | ||
1444 | bitmap_clear_bit (c->bbs, bb2->index); | |
1445 | EXECUTE_IF_SET_IN_BITMAP (c->bbs, 0, j, bj) | |
1446 | { | |
1447 | bb1 = BASIC_BLOCK (j); | |
1448 | bitmap_clear_bit (update_bbs, bb1->index); | |
1449 | ||
643400b8 | 1450 | replace_block_by (bb1, bb2); |
c9e93168 TV |
1451 | nr_bbs_removed++; |
1452 | } | |
1453 | } | |
1454 | ||
1455 | return nr_bbs_removed; | |
1456 | } | |
1457 | ||
1458 | /* Resets debug statement STMT if it has uses that are not dominated by their | |
1459 | defs. */ | |
1460 | ||
1461 | static void | |
1462 | update_debug_stmt (gimple stmt) | |
1463 | { | |
1464 | use_operand_p use_p; | |
1465 | ssa_op_iter oi; | |
1466 | basic_block bbdef, bbuse; | |
1467 | gimple def_stmt; | |
1468 | tree name; | |
1469 | ||
1470 | if (!gimple_debug_bind_p (stmt)) | |
1471 | return; | |
1472 | ||
1473 | bbuse = gimple_bb (stmt); | |
1474 | FOR_EACH_PHI_OR_STMT_USE (use_p, stmt, oi, SSA_OP_USE) | |
1475 | { | |
1476 | name = USE_FROM_PTR (use_p); | |
1477 | gcc_assert (TREE_CODE (name) == SSA_NAME); | |
1478 | ||
1479 | def_stmt = SSA_NAME_DEF_STMT (name); | |
1480 | gcc_assert (def_stmt != NULL); | |
1481 | ||
1482 | bbdef = gimple_bb (def_stmt); | |
1483 | if (bbdef == NULL || bbuse == bbdef | |
1484 | || dominated_by_p (CDI_DOMINATORS, bbuse, bbdef)) | |
1485 | continue; | |
1486 | ||
1487 | gimple_debug_bind_reset_value (stmt); | |
1488 | update_stmt (stmt); | |
1489 | } | |
1490 | } | |
1491 | ||
1492 | /* Resets all debug statements that have uses that are not | |
1493 | dominated by their defs. */ | |
1494 | ||
1495 | static void | |
1496 | update_debug_stmts (void) | |
1497 | { | |
1498 | basic_block bb; | |
1499 | bitmap_iterator bi; | |
1500 | unsigned int i; | |
1501 | ||
c9e93168 TV |
1502 | EXECUTE_IF_SET_IN_BITMAP (update_bbs, 0, i, bi) |
1503 | { | |
1504 | gimple stmt; | |
1505 | gimple_stmt_iterator gsi; | |
1506 | ||
1507 | bb = BASIC_BLOCK (i); | |
1508 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1509 | { | |
1510 | stmt = gsi_stmt (gsi); | |
1511 | if (!is_gimple_debug (stmt)) | |
1512 | continue; | |
1513 | update_debug_stmt (stmt); | |
1514 | } | |
1515 | } | |
1516 | } | |
1517 | ||
1518 | /* Runs tail merge optimization. */ | |
1519 | ||
1520 | unsigned int | |
1521 | tail_merge_optimize (unsigned int todo) | |
1522 | { | |
1523 | int nr_bbs_removed_total = 0; | |
1524 | int nr_bbs_removed; | |
1525 | bool loop_entered = false; | |
1526 | int iteration_nr = 0; | |
c9e93168 TV |
1527 | int max_iterations = PARAM_VALUE (PARAM_MAX_TAIL_MERGE_ITERATIONS); |
1528 | ||
1529 | if (!flag_tree_tail_merge || max_iterations == 0) | |
1530 | return 0; | |
1531 | ||
1532 | timevar_push (TV_TREE_TAIL_MERGE); | |
1533 | ||
1534 | calculate_dominance_info (CDI_DOMINATORS); | |
1535 | init_worklist (); | |
1536 | ||
1537 | while (!VEC_empty (same_succ, worklist)) | |
1538 | { | |
1539 | if (!loop_entered) | |
1540 | { | |
1541 | loop_entered = true; | |
1542 | alloc_cluster_vectors (); | |
1543 | update_bbs = BITMAP_ALLOC (NULL); | |
1544 | } | |
1545 | else | |
1546 | reset_cluster_vectors (); | |
1547 | ||
1548 | iteration_nr++; | |
1549 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1550 | fprintf (dump_file, "worklist iteration #%d\n", iteration_nr); | |
1551 | ||
1552 | find_clusters (); | |
1553 | gcc_assert (VEC_empty (same_succ, worklist)); | |
1554 | if (VEC_empty (bb_cluster, all_clusters)) | |
1555 | break; | |
1556 | ||
643400b8 | 1557 | nr_bbs_removed = apply_clusters (); |
c9e93168 TV |
1558 | nr_bbs_removed_total += nr_bbs_removed; |
1559 | if (nr_bbs_removed == 0) | |
1560 | break; | |
1561 | ||
643400b8 | 1562 | free_dominance_info (CDI_DOMINATORS); |
c9e93168 TV |
1563 | |
1564 | if (iteration_nr == max_iterations) | |
1565 | break; | |
1566 | ||
643400b8 | 1567 | calculate_dominance_info (CDI_DOMINATORS); |
c9e93168 TV |
1568 | update_worklist (); |
1569 | } | |
1570 | ||
1571 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1572 | fprintf (dump_file, "htab collision / search: %f\n", | |
1573 | htab_collisions (same_succ_htab)); | |
1574 | ||
1575 | if (nr_bbs_removed_total > 0) | |
1576 | { | |
643400b8 TV |
1577 | if (MAY_HAVE_DEBUG_STMTS) |
1578 | { | |
1579 | calculate_dominance_info (CDI_DOMINATORS); | |
1580 | update_debug_stmts (); | |
1581 | } | |
c9e93168 TV |
1582 | |
1583 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1584 | { | |
1585 | fprintf (dump_file, "Before TODOs.\n"); | |
1586 | dump_function_to_file (current_function_decl, dump_file, dump_flags); | |
1587 | } | |
1588 | ||
1589 | todo |= (TODO_verify_ssa | TODO_verify_stmts | TODO_verify_flow | |
1590 | | TODO_dump_func); | |
643400b8 | 1591 | mark_sym_for_renaming (gimple_vop (cfun)); |
c9e93168 TV |
1592 | } |
1593 | ||
1594 | delete_worklist (); | |
1595 | if (loop_entered) | |
1596 | { | |
1597 | delete_cluster_vectors (); | |
1598 | BITMAP_FREE (update_bbs); | |
1599 | } | |
1600 | ||
1601 | timevar_pop (TV_TREE_TAIL_MERGE); | |
1602 | ||
1603 | return todo; | |
1604 | } |