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a6540cbf | 1 | /* Basic block reordering routines for the GNU compiler. |
f1717362 | 2 | Copyright (C) 2000-2016 Free Software Foundation, Inc. |
a6540cbf | 3 | |
f12b58b3 | 4 | This file is part of GCC. |
a6540cbf | 5 | |
f12b58b3 | 6 | GCC is free software; you can redistribute it and/or modify it |
7 | under the terms of the GNU General Public License as published by | |
8c4c00c1 | 8 | the Free Software Foundation; either version 3, or (at your option) |
a6540cbf | 9 | any later version. |
10 | ||
f12b58b3 | 11 | GCC is distributed in the hope that it will be useful, but WITHOUT |
12 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY | |
13 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public | |
14 | License for more details. | |
a6540cbf | 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/>. */ | |
a6540cbf | 19 | |
2f619490 | 20 | /* This file contains the "reorder blocks" pass, which changes the control |
21 | flow of a function to encounter fewer branches; the "partition blocks" | |
22 | pass, which divides the basic blocks into "hot" and "cold" partitions, | |
23 | which are kept separate; and the "duplicate computed gotos" pass, which | |
24 | duplicates blocks ending in an indirect jump. | |
25 | ||
26 | There are two algorithms for "reorder blocks": the "simple" algorithm, | |
27 | which just rearranges blocks, trying to minimize the number of executed | |
28 | unconditional branches; and the "software trace cache" algorithm, which | |
29 | also copies code, and in general tries a lot harder to have long linear | |
30 | pieces of machine code executed. This algorithm is described next. */ | |
31 | ||
674f7a9c | 32 | /* This (greedy) algorithm constructs traces in several rounds. |
33 | The construction starts from "seeds". The seed for the first round | |
b2f6568f | 34 | is the entry point of the function. When there are more than one seed, |
35 | the one with the lowest key in the heap is selected first (see bb_to_key). | |
36 | Then the algorithm repeatedly adds the most probable successor to the end | |
37 | of a trace. Finally it connects the traces. | |
674f7a9c | 38 | |
39 | There are two parameters: Branch Threshold and Exec Threshold. | |
b2f6568f | 40 | If the probability of an edge to a successor of the current basic block is |
41 | lower than Branch Threshold or its frequency is lower than Exec Threshold, | |
42 | then the successor will be the seed in one of the next rounds. | |
674f7a9c | 43 | Each round has these parameters lower than the previous one. |
b2f6568f | 44 | The last round has to have these parameters set to zero so that the |
45 | remaining blocks are picked up. | |
674f7a9c | 46 | |
47 | The algorithm selects the most probable successor from all unvisited | |
48 | successors and successors that have been added to this trace. | |
49 | The other successors (that has not been "sent" to the next round) will be | |
b2f6568f | 50 | other seeds for this round and the secondary traces will start from them. |
51 | If the successor has not been visited in this trace, it is added to the | |
52 | trace (however, there is some heuristic for simple branches). | |
53 | If the successor has been visited in this trace, a loop has been found. | |
54 | If the loop has many iterations, the loop is rotated so that the source | |
55 | block of the most probable edge going out of the loop is the last block | |
56 | of the trace. | |
674f7a9c | 57 | If the loop has few iterations and there is no edge from the last block of |
b2f6568f | 58 | the loop going out of the loop, the loop header is duplicated. |
674f7a9c | 59 | |
b2f6568f | 60 | When connecting traces, the algorithm first checks whether there is an edge |
61 | from the last block of a trace to the first block of another trace. | |
674f7a9c | 62 | When there are still some unconnected traces it checks whether there exists |
b2f6568f | 63 | a basic block BB such that BB is a successor of the last block of a trace |
64 | and BB is a predecessor of the first block of another trace. In this case, | |
65 | BB is duplicated, added at the end of the first trace and the traces are | |
66 | connected through it. | |
674f7a9c | 67 | The rest of traces are simply connected so there will be a jump to the |
b2f6568f | 68 | beginning of the rest of traces. |
674f7a9c | 69 | |
e0b377e0 | 70 | The above description is for the full algorithm, which is used when the |
71 | function is optimized for speed. When the function is optimized for size, | |
72 | in order to reduce long jumps and connect more fallthru edges, the | |
73 | algorithm is modified as follows: | |
74 | (1) Break long traces to short ones. A trace is broken at a block that has | |
75 | multiple predecessors/ successors during trace discovery. When connecting | |
76 | traces, only connect Trace n with Trace n + 1. This change reduces most | |
77 | long jumps compared with the above algorithm. | |
78 | (2) Ignore the edge probability and frequency for fallthru edges. | |
79 | (3) Keep the original order of blocks when there is no chance to fall | |
80 | through. We rely on the results of cfg_cleanup. | |
81 | ||
82 | To implement the change for code size optimization, block's index is | |
83 | selected as the key and all traces are found in one round. | |
674f7a9c | 84 | |
85 | References: | |
86 | ||
87 | "Software Trace Cache" | |
88 | A. Ramirez, J. Larriba-Pey, C. Navarro, J. Torrellas and M. Valero; 1999 | |
89 | http://citeseer.nj.nec.com/15361.html | |
90 | ||
a6540cbf | 91 | */ |
92 | ||
93 | #include "config.h" | |
94 | #include "system.h" | |
805e22b2 | 95 | #include "coretypes.h" |
9ef16211 | 96 | #include "backend.h" |
7c29e30e | 97 | #include "target.h" |
a6540cbf | 98 | #include "rtl.h" |
7c29e30e | 99 | #include "tree.h" |
100 | #include "cfghooks.h" | |
9ef16211 | 101 | #include "df.h" |
7c29e30e | 102 | #include "optabs.h" |
42fe97ed | 103 | #include "regs.h" |
7c29e30e | 104 | #include "emit-rtl.h" |
a6540cbf | 105 | #include "output.h" |
4f18499c | 106 | #include "expr.h" |
b70a5a99 | 107 | #include "params.h" |
0b205f4c | 108 | #include "toplev.h" /* user_defined_section_attribute */ |
77fce4cd | 109 | #include "tree-pass.h" |
94ea8568 | 110 | #include "cfgrtl.h" |
111 | #include "cfganal.h" | |
112 | #include "cfgbuild.h" | |
113 | #include "cfgcleanup.h" | |
22d65d2c | 114 | #include "bb-reorder.h" |
f59cbcbf | 115 | #include "except.h" |
08496072 | 116 | #include "fibonacci_heap.h" |
77fce4cd | 117 | |
4f18499c | 118 | /* The number of rounds. In most cases there will only be 4 rounds, but |
119 | when partitioning hot and cold basic blocks into separate sections of | |
b2f6568f | 120 | the object file there will be an extra round. */ |
4f18499c | 121 | #define N_ROUNDS 5 |
674f7a9c | 122 | |
22d65d2c | 123 | struct target_bb_reorder default_target_bb_reorder; |
124 | #if SWITCHABLE_TARGET | |
125 | struct target_bb_reorder *this_target_bb_reorder = &default_target_bb_reorder; | |
126 | #endif | |
127 | ||
128 | #define uncond_jump_length \ | |
129 | (this_target_bb_reorder->x_uncond_jump_length) | |
130 | ||
674f7a9c | 131 | /* Branch thresholds in thousandths (per mille) of the REG_BR_PROB_BASE. */ |
7b38ffff | 132 | static const int branch_threshold[N_ROUNDS] = {400, 200, 100, 0, 0}; |
674f7a9c | 133 | |
134 | /* Exec thresholds in thousandths (per mille) of the frequency of bb 0. */ | |
7b38ffff | 135 | static const int exec_threshold[N_ROUNDS] = {500, 200, 50, 0, 0}; |
674f7a9c | 136 | |
137 | /* If edge frequency is lower than DUPLICATION_THRESHOLD per mille of entry | |
138 | block the edge destination is not duplicated while connecting traces. */ | |
139 | #define DUPLICATION_THRESHOLD 100 | |
140 | ||
08496072 | 141 | typedef fibonacci_heap <long, basic_block_def> bb_heap_t; |
142 | typedef fibonacci_node <long, basic_block_def> bb_heap_node_t; | |
143 | ||
674f7a9c | 144 | /* Structure to hold needed information for each basic block. */ |
6dc50383 | 145 | struct bbro_basic_block_data |
674f7a9c | 146 | { |
b2f6568f | 147 | /* Which trace is the bb start of (-1 means it is not a start of any). */ |
674f7a9c | 148 | int start_of_trace; |
149 | ||
b2f6568f | 150 | /* Which trace is the bb end of (-1 means it is not an end of any). */ |
674f7a9c | 151 | int end_of_trace; |
152 | ||
1897b881 | 153 | /* Which trace is the bb in? */ |
154 | int in_trace; | |
155 | ||
43e94e51 | 156 | /* Which trace was this bb visited in? */ |
157 | int visited; | |
158 | ||
674f7a9c | 159 | /* Which heap is BB in (if any)? */ |
08496072 | 160 | bb_heap_t *heap; |
674f7a9c | 161 | |
162 | /* Which heap node is BB in (if any)? */ | |
08496072 | 163 | bb_heap_node_t *node; |
6dc50383 | 164 | }; |
674f7a9c | 165 | |
166 | /* The current size of the following dynamic array. */ | |
167 | static int array_size; | |
168 | ||
169 | /* The array which holds needed information for basic blocks. */ | |
170 | static bbro_basic_block_data *bbd; | |
171 | ||
172 | /* To avoid frequent reallocation the size of arrays is greater than needed, | |
173 | the number of elements is (not less than) 1.25 * size_wanted. */ | |
174 | #define GET_ARRAY_SIZE(X) ((((X) / 4) + 1) * 5) | |
175 | ||
176 | /* Free the memory and set the pointer to NULL. */ | |
64db345d | 177 | #define FREE(P) (gcc_assert (P), free (P), P = 0) |
674f7a9c | 178 | |
179 | /* Structure for holding information about a trace. */ | |
180 | struct trace | |
181 | { | |
182 | /* First and last basic block of the trace. */ | |
183 | basic_block first, last; | |
184 | ||
185 | /* The round of the STC creation which this trace was found in. */ | |
186 | int round; | |
187 | ||
188 | /* The length (i.e. the number of basic blocks) of the trace. */ | |
189 | int length; | |
190 | }; | |
191 | ||
192 | /* Maximum frequency and count of one of the entry blocks. */ | |
ffcdc9fa | 193 | static int max_entry_frequency; |
194 | static gcov_type max_entry_count; | |
674f7a9c | 195 | |
a6540cbf | 196 | /* Local function prototypes. */ |
aecda0d6 | 197 | static void find_traces (int *, struct trace *); |
198 | static basic_block rotate_loop (edge, struct trace *, int); | |
199 | static void mark_bb_visited (basic_block, int); | |
200 | static void find_traces_1_round (int, int, gcov_type, struct trace *, int *, | |
08496072 | 201 | int, bb_heap_t **, int); |
aecda0d6 | 202 | static basic_block copy_bb (basic_block, edge, basic_block, int); |
08496072 | 203 | static long bb_to_key (basic_block); |
b2f6568f | 204 | static bool better_edge_p (const_basic_block, const_edge, int, int, int, int, |
205 | const_edge); | |
e0b377e0 | 206 | static bool connect_better_edge_p (const_edge, bool, int, const_edge, |
207 | struct trace *); | |
aecda0d6 | 208 | static void connect_traces (int, struct trace *); |
5493cb9a | 209 | static bool copy_bb_p (const_basic_block, int); |
7ecb5bb2 | 210 | static bool push_to_next_round_p (const_basic_block, int, int, int, gcov_type); |
075d20cf | 211 | \f |
43e94e51 | 212 | /* Return the trace number in which BB was visited. */ |
213 | ||
214 | static int | |
215 | bb_visited_trace (const_basic_block bb) | |
216 | { | |
217 | gcc_assert (bb->index < array_size); | |
218 | return bbd[bb->index].visited; | |
219 | } | |
220 | ||
221 | /* This function marks BB that it was visited in trace number TRACE. */ | |
222 | ||
223 | static void | |
224 | mark_bb_visited (basic_block bb, int trace) | |
225 | { | |
226 | bbd[bb->index].visited = trace; | |
227 | if (bbd[bb->index].heap) | |
228 | { | |
08496072 | 229 | bbd[bb->index].heap->delete_node (bbd[bb->index].node); |
43e94e51 | 230 | bbd[bb->index].heap = NULL; |
231 | bbd[bb->index].node = NULL; | |
232 | } | |
233 | } | |
234 | ||
4f18499c | 235 | /* Check to see if bb should be pushed into the next round of trace |
236 | collections or not. Reasons for pushing the block forward are 1). | |
237 | If the block is cold, we are doing partitioning, and there will be | |
238 | another round (cold partition blocks are not supposed to be | |
239 | collected into traces until the very last round); or 2). There will | |
240 | be another round, and the basic block is not "hot enough" for the | |
241 | current round of trace collection. */ | |
242 | ||
243 | static bool | |
7ecb5bb2 | 244 | push_to_next_round_p (const_basic_block bb, int round, int number_of_rounds, |
4f18499c | 245 | int exec_th, gcov_type count_th) |
246 | { | |
247 | bool there_exists_another_round; | |
4f18499c | 248 | bool block_not_hot_enough; |
249 | ||
250 | there_exists_another_round = round < number_of_rounds - 1; | |
4f18499c | 251 | |
a0c938f0 | 252 | block_not_hot_enough = (bb->frequency < exec_th |
4f18499c | 253 | || bb->count < count_th |
8d672d12 | 254 | || probably_never_executed_bb_p (cfun, bb)); |
4f18499c | 255 | |
1897b881 | 256 | if (there_exists_another_round |
257 | && block_not_hot_enough) | |
4f18499c | 258 | return true; |
a0c938f0 | 259 | else |
4f18499c | 260 | return false; |
261 | } | |
262 | ||
674f7a9c | 263 | /* Find the traces for Software Trace Cache. Chain each trace through |
264 | RBI()->next. Store the number of traces to N_TRACES and description of | |
265 | traces to TRACES. */ | |
a6540cbf | 266 | |
075d20cf | 267 | static void |
aecda0d6 | 268 | find_traces (int *n_traces, struct trace *traces) |
a6540cbf | 269 | { |
674f7a9c | 270 | int i; |
4f18499c | 271 | int number_of_rounds; |
674f7a9c | 272 | edge e; |
cd665a06 | 273 | edge_iterator ei; |
08496072 | 274 | bb_heap_t *heap = new bb_heap_t (LONG_MIN); |
674f7a9c | 275 | |
4f18499c | 276 | /* Add one extra round of trace collection when partitioning hot/cold |
277 | basic blocks into separate sections. The last round is for all the | |
278 | cold blocks (and ONLY the cold blocks). */ | |
279 | ||
280 | number_of_rounds = N_ROUNDS - 1; | |
4f18499c | 281 | |
674f7a9c | 282 | /* Insert entry points of function into heap. */ |
674f7a9c | 283 | max_entry_frequency = 0; |
284 | max_entry_count = 0; | |
34154e27 | 285 | FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs) |
674f7a9c | 286 | { |
287 | bbd[e->dest->index].heap = heap; | |
08496072 | 288 | bbd[e->dest->index].node = heap->insert (bb_to_key (e->dest), e->dest); |
674f7a9c | 289 | if (e->dest->frequency > max_entry_frequency) |
290 | max_entry_frequency = e->dest->frequency; | |
291 | if (e->dest->count > max_entry_count) | |
292 | max_entry_count = e->dest->count; | |
293 | } | |
294 | ||
295 | /* Find the traces. */ | |
4f18499c | 296 | for (i = 0; i < number_of_rounds; i++) |
674f7a9c | 297 | { |
298 | gcov_type count_threshold; | |
075d20cf | 299 | |
450d042a | 300 | if (dump_file) |
301 | fprintf (dump_file, "STC - round %d\n", i + 1); | |
674f7a9c | 302 | |
303 | if (max_entry_count < INT_MAX / 1000) | |
304 | count_threshold = max_entry_count * exec_threshold[i] / 1000; | |
305 | else | |
306 | count_threshold = max_entry_count / 1000 * exec_threshold[i]; | |
307 | ||
308 | find_traces_1_round (REG_BR_PROB_BASE * branch_threshold[i] / 1000, | |
309 | max_entry_frequency * exec_threshold[i] / 1000, | |
4f18499c | 310 | count_threshold, traces, n_traces, i, &heap, |
311 | number_of_rounds); | |
674f7a9c | 312 | } |
08496072 | 313 | delete heap; |
674f7a9c | 314 | |
450d042a | 315 | if (dump_file) |
674f7a9c | 316 | { |
317 | for (i = 0; i < *n_traces; i++) | |
318 | { | |
319 | basic_block bb; | |
450d042a | 320 | fprintf (dump_file, "Trace %d (round %d): ", i + 1, |
674f7a9c | 321 | traces[i].round + 1); |
b2f6568f | 322 | for (bb = traces[i].first; |
323 | bb != traces[i].last; | |
324 | bb = (basic_block) bb->aux) | |
450d042a | 325 | fprintf (dump_file, "%d [%d] ", bb->index, bb->frequency); |
326 | fprintf (dump_file, "%d [%d]\n", bb->index, bb->frequency); | |
674f7a9c | 327 | } |
450d042a | 328 | fflush (dump_file); |
674f7a9c | 329 | } |
330 | } | |
331 | ||
332 | /* Rotate loop whose back edge is BACK_EDGE in the tail of trace TRACE | |
333 | (with sequential number TRACE_N). */ | |
334 | ||
335 | static basic_block | |
aecda0d6 | 336 | rotate_loop (edge back_edge, struct trace *trace, int trace_n) |
674f7a9c | 337 | { |
338 | basic_block bb; | |
339 | ||
340 | /* Information about the best end (end after rotation) of the loop. */ | |
341 | basic_block best_bb = NULL; | |
342 | edge best_edge = NULL; | |
343 | int best_freq = -1; | |
344 | gcov_type best_count = -1; | |
345 | /* The best edge is preferred when its destination is not visited yet | |
346 | or is a start block of some trace. */ | |
347 | bool is_preferred = false; | |
348 | ||
349 | /* Find the most frequent edge that goes out from current trace. */ | |
350 | bb = back_edge->dest; | |
075d20cf | 351 | do |
352 | { | |
674f7a9c | 353 | edge e; |
cd665a06 | 354 | edge_iterator ei; |
355 | ||
356 | FOR_EACH_EDGE (e, ei, bb->succs) | |
34154e27 | 357 | if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun) |
43e94e51 | 358 | && bb_visited_trace (e->dest) != trace_n |
674f7a9c | 359 | && (e->flags & EDGE_CAN_FALLTHRU) |
360 | && !(e->flags & EDGE_COMPLEX)) | |
361 | { | |
362 | if (is_preferred) | |
363 | { | |
364 | /* The best edge is preferred. */ | |
43e94e51 | 365 | if (!bb_visited_trace (e->dest) |
674f7a9c | 366 | || bbd[e->dest->index].start_of_trace >= 0) |
367 | { | |
368 | /* The current edge E is also preferred. */ | |
369 | int freq = EDGE_FREQUENCY (e); | |
370 | if (freq > best_freq || e->count > best_count) | |
371 | { | |
372 | best_freq = freq; | |
373 | best_count = e->count; | |
374 | best_edge = e; | |
375 | best_bb = bb; | |
376 | } | |
377 | } | |
378 | } | |
379 | else | |
380 | { | |
43e94e51 | 381 | if (!bb_visited_trace (e->dest) |
674f7a9c | 382 | || bbd[e->dest->index].start_of_trace >= 0) |
383 | { | |
384 | /* The current edge E is preferred. */ | |
385 | is_preferred = true; | |
386 | best_freq = EDGE_FREQUENCY (e); | |
387 | best_count = e->count; | |
388 | best_edge = e; | |
389 | best_bb = bb; | |
390 | } | |
391 | else | |
392 | { | |
393 | int freq = EDGE_FREQUENCY (e); | |
394 | if (!best_edge || freq > best_freq || e->count > best_count) | |
395 | { | |
396 | best_freq = freq; | |
397 | best_count = e->count; | |
398 | best_edge = e; | |
399 | best_bb = bb; | |
400 | } | |
401 | } | |
402 | } | |
403 | } | |
364c0c59 | 404 | bb = (basic_block) bb->aux; |
674f7a9c | 405 | } |
406 | while (bb != back_edge->dest); | |
407 | ||
408 | if (best_bb) | |
409 | { | |
410 | /* Rotate the loop so that the BEST_EDGE goes out from the last block of | |
411 | the trace. */ | |
412 | if (back_edge->dest == trace->first) | |
413 | { | |
364c0c59 | 414 | trace->first = (basic_block) best_bb->aux; |
674f7a9c | 415 | } |
416 | else | |
417 | { | |
418 | basic_block prev_bb; | |
9342ee68 | 419 | |
674f7a9c | 420 | for (prev_bb = trace->first; |
bc5f266a | 421 | prev_bb->aux != back_edge->dest; |
364c0c59 | 422 | prev_bb = (basic_block) prev_bb->aux) |
674f7a9c | 423 | ; |
bc5f266a | 424 | prev_bb->aux = best_bb->aux; |
674f7a9c | 425 | |
426 | /* Try to get rid of uncond jump to cond jump. */ | |
ea091dfd | 427 | if (single_succ_p (prev_bb)) |
674f7a9c | 428 | { |
ea091dfd | 429 | basic_block header = single_succ (prev_bb); |
674f7a9c | 430 | |
431 | /* Duplicate HEADER if it is a small block containing cond jump | |
432 | in the end. */ | |
065efcb1 | 433 | if (any_condjump_p (BB_END (header)) && copy_bb_p (header, 0) |
8f869004 | 434 | && !CROSSING_JUMP_P (BB_END (header))) |
ea091dfd | 435 | copy_bb (header, single_succ_edge (prev_bb), prev_bb, trace_n); |
674f7a9c | 436 | } |
437 | } | |
438 | } | |
439 | else | |
440 | { | |
441 | /* We have not found suitable loop tail so do no rotation. */ | |
442 | best_bb = back_edge->src; | |
a6540cbf | 443 | } |
bc5f266a | 444 | best_bb->aux = NULL; |
674f7a9c | 445 | return best_bb; |
075d20cf | 446 | } |
a6540cbf | 447 | |
b2f6568f | 448 | /* One round of finding traces. Find traces for BRANCH_TH and EXEC_TH i.e. do |
449 | not include basic blocks whose probability is lower than BRANCH_TH or whose | |
450 | frequency is lower than EXEC_TH into traces (or whose count is lower than | |
451 | COUNT_TH). Store the new traces into TRACES and modify the number of | |
452 | traces *N_TRACES. Set the round (which the trace belongs to) to ROUND. | |
453 | The function expects starting basic blocks to be in *HEAP and will delete | |
454 | *HEAP and store starting points for the next round into new *HEAP. */ | |
674f7a9c | 455 | |
456 | static void | |
aecda0d6 | 457 | find_traces_1_round (int branch_th, int exec_th, gcov_type count_th, |
458 | struct trace *traces, int *n_traces, int round, | |
08496072 | 459 | bb_heap_t **heap, int number_of_rounds) |
674f7a9c | 460 | { |
461 | /* Heap for discarded basic blocks which are possible starting points for | |
462 | the next round. */ | |
08496072 | 463 | bb_heap_t *new_heap = new bb_heap_t (LONG_MIN); |
e0b377e0 | 464 | bool for_size = optimize_function_for_size_p (cfun); |
674f7a9c | 465 | |
08496072 | 466 | while (!(*heap)->empty ()) |
674f7a9c | 467 | { |
468 | basic_block bb; | |
469 | struct trace *trace; | |
470 | edge best_edge, e; | |
08496072 | 471 | long key; |
cd665a06 | 472 | edge_iterator ei; |
674f7a9c | 473 | |
08496072 | 474 | bb = (*heap)->extract_min (); |
674f7a9c | 475 | bbd[bb->index].heap = NULL; |
476 | bbd[bb->index].node = NULL; | |
477 | ||
450d042a | 478 | if (dump_file) |
479 | fprintf (dump_file, "Getting bb %d\n", bb->index); | |
674f7a9c | 480 | |
b2f6568f | 481 | /* If the BB's frequency is too low, send BB to the next round. When |
a0c938f0 | 482 | partitioning hot/cold blocks into separate sections, make sure all |
483 | the cold blocks (and ONLY the cold blocks) go into the (extra) final | |
e0b377e0 | 484 | round. When optimizing for size, do not push to next round. */ |
4f18499c | 485 | |
e0b377e0 | 486 | if (!for_size |
487 | && push_to_next_round_p (bb, round, number_of_rounds, exec_th, | |
488 | count_th)) | |
674f7a9c | 489 | { |
490 | int key = bb_to_key (bb); | |
491 | bbd[bb->index].heap = new_heap; | |
08496072 | 492 | bbd[bb->index].node = new_heap->insert (key, bb); |
674f7a9c | 493 | |
450d042a | 494 | if (dump_file) |
495 | fprintf (dump_file, | |
674f7a9c | 496 | " Possible start point of next round: %d (key: %d)\n", |
497 | bb->index, key); | |
498 | continue; | |
499 | } | |
500 | ||
501 | trace = traces + *n_traces; | |
502 | trace->first = bb; | |
503 | trace->round = round; | |
504 | trace->length = 0; | |
1897b881 | 505 | bbd[bb->index].in_trace = *n_traces; |
674f7a9c | 506 | (*n_traces)++; |
507 | ||
508 | do | |
509 | { | |
510 | int prob, freq; | |
21cc5e1a | 511 | bool ends_in_call; |
674f7a9c | 512 | |
513 | /* The probability and frequency of the best edge. */ | |
514 | int best_prob = INT_MIN / 2; | |
515 | int best_freq = INT_MIN / 2; | |
516 | ||
517 | best_edge = NULL; | |
518 | mark_bb_visited (bb, *n_traces); | |
519 | trace->length++; | |
520 | ||
450d042a | 521 | if (dump_file) |
522 | fprintf (dump_file, "Basic block %d was visited in trace %d\n", | |
674f7a9c | 523 | bb->index, *n_traces - 1); |
524 | ||
a0c938f0 | 525 | ends_in_call = block_ends_with_call_p (bb); |
21cc5e1a | 526 | |
674f7a9c | 527 | /* Select the successor that will be placed after BB. */ |
cd665a06 | 528 | FOR_EACH_EDGE (e, ei, bb->succs) |
674f7a9c | 529 | { |
64db345d | 530 | gcc_assert (!(e->flags & EDGE_FAKE)); |
674f7a9c | 531 | |
34154e27 | 532 | if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
674f7a9c | 533 | continue; |
534 | ||
43e94e51 | 535 | if (bb_visited_trace (e->dest) |
536 | && bb_visited_trace (e->dest) != *n_traces) | |
674f7a9c | 537 | continue; |
538 | ||
1897b881 | 539 | if (BB_PARTITION (e->dest) != BB_PARTITION (bb)) |
4f18499c | 540 | continue; |
541 | ||
674f7a9c | 542 | prob = e->probability; |
aff1d083 | 543 | freq = e->dest->frequency; |
674f7a9c | 544 | |
21cc5e1a | 545 | /* The only sensible preference for a call instruction is the |
546 | fallthru edge. Don't bother selecting anything else. */ | |
547 | if (ends_in_call) | |
548 | { | |
549 | if (e->flags & EDGE_CAN_FALLTHRU) | |
550 | { | |
551 | best_edge = e; | |
552 | best_prob = prob; | |
553 | best_freq = freq; | |
554 | } | |
555 | continue; | |
556 | } | |
557 | ||
674f7a9c | 558 | /* Edge that cannot be fallthru or improbable or infrequent |
e0b377e0 | 559 | successor (i.e. it is unsuitable successor). When optimizing |
560 | for size, ignore the probability and frequency. */ | |
674f7a9c | 561 | if (!(e->flags & EDGE_CAN_FALLTHRU) || (e->flags & EDGE_COMPLEX) |
e0b377e0 | 562 | || ((prob < branch_th || EDGE_FREQUENCY (e) < exec_th |
563 | || e->count < count_th) && (!for_size))) | |
674f7a9c | 564 | continue; |
565 | ||
4f18499c | 566 | /* If partitioning hot/cold basic blocks, don't consider edges |
567 | that cross section boundaries. */ | |
568 | ||
569 | if (better_edge_p (bb, e, prob, freq, best_prob, best_freq, | |
570 | best_edge)) | |
674f7a9c | 571 | { |
572 | best_edge = e; | |
573 | best_prob = prob; | |
574 | best_freq = freq; | |
575 | } | |
576 | } | |
577 | ||
3ff6ad35 | 578 | /* If the best destination has multiple predecessors, and can be |
d5ade7f4 | 579 | duplicated cheaper than a jump, don't allow it to be added |
580 | to a trace. We'll duplicate it when connecting traces. */ | |
cd665a06 | 581 | if (best_edge && EDGE_COUNT (best_edge->dest->preds) >= 2 |
d5ade7f4 | 582 | && copy_bb_p (best_edge->dest, 0)) |
583 | best_edge = NULL; | |
584 | ||
e0b377e0 | 585 | /* If the best destination has multiple successors or predecessors, |
586 | don't allow it to be added when optimizing for size. This makes | |
587 | sure predecessors with smaller index are handled before the best | |
588 | destinarion. It breaks long trace and reduces long jumps. | |
589 | ||
590 | Take if-then-else as an example. | |
591 | A | |
592 | / \ | |
593 | B C | |
594 | \ / | |
595 | D | |
596 | If we do not remove the best edge B->D/C->D, the final order might | |
597 | be A B D ... C. C is at the end of the program. If D's successors | |
598 | and D are complicated, might need long jumps for A->C and C->D. | |
599 | Similar issue for order: A C D ... B. | |
600 | ||
601 | After removing the best edge, the final result will be ABCD/ ACBD. | |
602 | It does not add jump compared with the previous order. But it | |
a04e8d62 | 603 | reduces the possibility of long jumps. */ |
e0b377e0 | 604 | if (best_edge && for_size |
605 | && (EDGE_COUNT (best_edge->dest->succs) > 1 | |
606 | || EDGE_COUNT (best_edge->dest->preds) > 1)) | |
607 | best_edge = NULL; | |
608 | ||
674f7a9c | 609 | /* Add all non-selected successors to the heaps. */ |
cd665a06 | 610 | FOR_EACH_EDGE (e, ei, bb->succs) |
674f7a9c | 611 | { |
612 | if (e == best_edge | |
34154e27 | 613 | || e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun) |
43e94e51 | 614 | || bb_visited_trace (e->dest)) |
674f7a9c | 615 | continue; |
616 | ||
617 | key = bb_to_key (e->dest); | |
618 | ||
619 | if (bbd[e->dest->index].heap) | |
620 | { | |
621 | /* E->DEST is already in some heap. */ | |
08496072 | 622 | if (key != bbd[e->dest->index].node->get_key ()) |
674f7a9c | 623 | { |
450d042a | 624 | if (dump_file) |
674f7a9c | 625 | { |
450d042a | 626 | fprintf (dump_file, |
674f7a9c | 627 | "Changing key for bb %d from %ld to %ld.\n", |
628 | e->dest->index, | |
08496072 | 629 | (long) bbd[e->dest->index].node->get_key (), |
674f7a9c | 630 | key); |
631 | } | |
6d0128c8 | 632 | bbd[e->dest->index].heap->replace_key |
08496072 | 633 | (bbd[e->dest->index].node, key); |
674f7a9c | 634 | } |
635 | } | |
636 | else | |
637 | { | |
08496072 | 638 | bb_heap_t *which_heap = *heap; |
674f7a9c | 639 | |
640 | prob = e->probability; | |
641 | freq = EDGE_FREQUENCY (e); | |
642 | ||
643 | if (!(e->flags & EDGE_CAN_FALLTHRU) | |
644 | || (e->flags & EDGE_COMPLEX) | |
645 | || prob < branch_th || freq < exec_th | |
646 | || e->count < count_th) | |
647 | { | |
4f18499c | 648 | /* When partitioning hot/cold basic blocks, make sure |
649 | the cold blocks (and only the cold blocks) all get | |
e0b377e0 | 650 | pushed to the last round of trace collection. When |
651 | optimizing for size, do not push to next round. */ | |
4f18499c | 652 | |
e0b377e0 | 653 | if (!for_size && push_to_next_round_p (e->dest, round, |
654 | number_of_rounds, | |
655 | exec_th, count_th)) | |
674f7a9c | 656 | which_heap = new_heap; |
657 | } | |
a6540cbf | 658 | |
674f7a9c | 659 | bbd[e->dest->index].heap = which_heap; |
08496072 | 660 | bbd[e->dest->index].node = which_heap->insert (key, e->dest); |
a6540cbf | 661 | |
450d042a | 662 | if (dump_file) |
674f7a9c | 663 | { |
450d042a | 664 | fprintf (dump_file, |
674f7a9c | 665 | " Possible start of %s round: %d (key: %ld)\n", |
666 | (which_heap == new_heap) ? "next" : "this", | |
667 | e->dest->index, (long) key); | |
668 | } | |
669 | ||
670 | } | |
671 | } | |
672 | ||
673 | if (best_edge) /* Suitable successor was found. */ | |
674 | { | |
43e94e51 | 675 | if (bb_visited_trace (best_edge->dest) == *n_traces) |
674f7a9c | 676 | { |
677 | /* We do nothing with one basic block loops. */ | |
678 | if (best_edge->dest != bb) | |
679 | { | |
680 | if (EDGE_FREQUENCY (best_edge) | |
681 | > 4 * best_edge->dest->frequency / 5) | |
682 | { | |
683 | /* The loop has at least 4 iterations. If the loop | |
684 | header is not the first block of the function | |
685 | we can rotate the loop. */ | |
686 | ||
34154e27 | 687 | if (best_edge->dest |
688 | != ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb) | |
674f7a9c | 689 | { |
450d042a | 690 | if (dump_file) |
674f7a9c | 691 | { |
450d042a | 692 | fprintf (dump_file, |
674f7a9c | 693 | "Rotating loop %d - %d\n", |
694 | best_edge->dest->index, bb->index); | |
695 | } | |
bc5f266a | 696 | bb->aux = best_edge->dest; |
a0c938f0 | 697 | bbd[best_edge->dest->index].in_trace = |
698 | (*n_traces) - 1; | |
674f7a9c | 699 | bb = rotate_loop (best_edge, trace, *n_traces); |
700 | } | |
701 | } | |
702 | else | |
703 | { | |
704 | /* The loop has less than 4 iterations. */ | |
705 | ||
ea091dfd | 706 | if (single_succ_p (bb) |
0bfd8d5c | 707 | && copy_bb_p (best_edge->dest, |
b2f6568f | 708 | optimize_edge_for_speed_p |
709 | (best_edge))) | |
674f7a9c | 710 | { |
711 | bb = copy_bb (best_edge->dest, best_edge, bb, | |
712 | *n_traces); | |
1897b881 | 713 | trace->length++; |
674f7a9c | 714 | } |
715 | } | |
716 | } | |
717 | ||
718 | /* Terminate the trace. */ | |
719 | break; | |
720 | } | |
721 | else | |
722 | { | |
723 | /* Check for a situation | |
724 | ||
725 | A | |
726 | /| | |
727 | B | | |
728 | \| | |
729 | C | |
730 | ||
731 | where | |
732 | EDGE_FREQUENCY (AB) + EDGE_FREQUENCY (BC) | |
733 | >= EDGE_FREQUENCY (AC). | |
734 | (i.e. 2 * B->frequency >= EDGE_FREQUENCY (AC) ) | |
735 | Best ordering is then A B C. | |
736 | ||
e0b377e0 | 737 | When optimizing for size, A B C is always the best order. |
738 | ||
674f7a9c | 739 | This situation is created for example by: |
740 | ||
741 | if (A) B; | |
742 | C; | |
743 | ||
744 | */ | |
745 | ||
cd665a06 | 746 | FOR_EACH_EDGE (e, ei, bb->succs) |
674f7a9c | 747 | if (e != best_edge |
748 | && (e->flags & EDGE_CAN_FALLTHRU) | |
749 | && !(e->flags & EDGE_COMPLEX) | |
43e94e51 | 750 | && !bb_visited_trace (e->dest) |
ea091dfd | 751 | && single_pred_p (e->dest) |
9858d888 | 752 | && !(e->flags & EDGE_CROSSING) |
1897b881 | 753 | && single_succ_p (e->dest) |
ea091dfd | 754 | && (single_succ_edge (e->dest)->flags |
755 | & EDGE_CAN_FALLTHRU) | |
756 | && !(single_succ_edge (e->dest)->flags & EDGE_COMPLEX) | |
757 | && single_succ (e->dest) == best_edge->dest | |
e0b377e0 | 758 | && (2 * e->dest->frequency >= EDGE_FREQUENCY (best_edge) |
759 | || for_size)) | |
674f7a9c | 760 | { |
761 | best_edge = e; | |
450d042a | 762 | if (dump_file) |
763 | fprintf (dump_file, "Selecting BB %d\n", | |
674f7a9c | 764 | best_edge->dest->index); |
765 | break; | |
766 | } | |
767 | ||
bc5f266a | 768 | bb->aux = best_edge->dest; |
1897b881 | 769 | bbd[best_edge->dest->index].in_trace = (*n_traces) - 1; |
674f7a9c | 770 | bb = best_edge->dest; |
771 | } | |
772 | } | |
773 | } | |
774 | while (best_edge); | |
775 | trace->last = bb; | |
776 | bbd[trace->first->index].start_of_trace = *n_traces - 1; | |
777 | bbd[trace->last->index].end_of_trace = *n_traces - 1; | |
778 | ||
779 | /* The trace is terminated so we have to recount the keys in heap | |
780 | (some block can have a lower key because now one of its predecessors | |
781 | is an end of the trace). */ | |
cd665a06 | 782 | FOR_EACH_EDGE (e, ei, bb->succs) |
674f7a9c | 783 | { |
34154e27 | 784 | if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun) |
43e94e51 | 785 | || bb_visited_trace (e->dest)) |
674f7a9c | 786 | continue; |
787 | ||
788 | if (bbd[e->dest->index].heap) | |
789 | { | |
790 | key = bb_to_key (e->dest); | |
08496072 | 791 | if (key != bbd[e->dest->index].node->get_key ()) |
674f7a9c | 792 | { |
450d042a | 793 | if (dump_file) |
674f7a9c | 794 | { |
450d042a | 795 | fprintf (dump_file, |
674f7a9c | 796 | "Changing key for bb %d from %ld to %ld.\n", |
797 | e->dest->index, | |
08496072 | 798 | (long) bbd[e->dest->index].node->get_key (), key); |
674f7a9c | 799 | } |
6d0128c8 | 800 | bbd[e->dest->index].heap->replace_key |
08496072 | 801 | (bbd[e->dest->index].node, key); |
674f7a9c | 802 | } |
803 | } | |
804 | } | |
805 | } | |
806 | ||
08496072 | 807 | delete (*heap); |
674f7a9c | 808 | |
809 | /* "Return" the new heap. */ | |
810 | *heap = new_heap; | |
811 | } | |
812 | ||
813 | /* Create a duplicate of the basic block OLD_BB and redirect edge E to it, add | |
814 | it to trace after BB, mark OLD_BB visited and update pass' data structures | |
815 | (TRACE is a number of trace which OLD_BB is duplicated to). */ | |
a6540cbf | 816 | |
075d20cf | 817 | static basic_block |
aecda0d6 | 818 | copy_bb (basic_block old_bb, edge e, basic_block bb, int trace) |
075d20cf | 819 | { |
674f7a9c | 820 | basic_block new_bb; |
821 | ||
c4d867e0 | 822 | new_bb = duplicate_block (old_bb, e, bb); |
7562ed74 | 823 | BB_COPY_PARTITION (new_bb, old_bb); |
065efcb1 | 824 | |
64db345d | 825 | gcc_assert (e->dest == new_bb); |
64db345d | 826 | |
450d042a | 827 | if (dump_file) |
828 | fprintf (dump_file, | |
674f7a9c | 829 | "Duplicated bb %d (created bb %d)\n", |
830 | old_bb->index, new_bb->index); | |
075d20cf | 831 | |
fe672ac0 | 832 | if (new_bb->index >= array_size |
833 | || last_basic_block_for_fn (cfun) > array_size) | |
a6540cbf | 834 | { |
674f7a9c | 835 | int i; |
836 | int new_size; | |
837 | ||
fe672ac0 | 838 | new_size = MAX (last_basic_block_for_fn (cfun), new_bb->index + 1); |
674f7a9c | 839 | new_size = GET_ARRAY_SIZE (new_size); |
364c0c59 | 840 | bbd = XRESIZEVEC (bbro_basic_block_data, bbd, new_size); |
674f7a9c | 841 | for (i = array_size; i < new_size; i++) |
842 | { | |
843 | bbd[i].start_of_trace = -1; | |
844 | bbd[i].end_of_trace = -1; | |
43e94e51 | 845 | bbd[i].in_trace = -1; |
846 | bbd[i].visited = 0; | |
674f7a9c | 847 | bbd[i].heap = NULL; |
848 | bbd[i].node = NULL; | |
849 | } | |
850 | array_size = new_size; | |
a6540cbf | 851 | |
450d042a | 852 | if (dump_file) |
674f7a9c | 853 | { |
450d042a | 854 | fprintf (dump_file, |
674f7a9c | 855 | "Growing the dynamic array to %d elements.\n", |
856 | array_size); | |
857 | } | |
a6540cbf | 858 | } |
674f7a9c | 859 | |
43e94e51 | 860 | gcc_assert (!bb_visited_trace (e->dest)); |
861 | mark_bb_visited (new_bb, trace); | |
862 | new_bb->aux = bb->aux; | |
863 | bb->aux = new_bb; | |
864 | ||
1897b881 | 865 | bbd[new_bb->index].in_trace = trace; |
866 | ||
674f7a9c | 867 | return new_bb; |
868 | } | |
869 | ||
870 | /* Compute and return the key (for the heap) of the basic block BB. */ | |
871 | ||
08496072 | 872 | static long |
aecda0d6 | 873 | bb_to_key (basic_block bb) |
674f7a9c | 874 | { |
875 | edge e; | |
cd665a06 | 876 | edge_iterator ei; |
674f7a9c | 877 | int priority = 0; |
878 | ||
e0b377e0 | 879 | /* Use index as key to align with its original order. */ |
880 | if (optimize_function_for_size_p (cfun)) | |
881 | return bb->index; | |
882 | ||
674f7a9c | 883 | /* Do not start in probably never executed blocks. */ |
4f18499c | 884 | |
7562ed74 | 885 | if (BB_PARTITION (bb) == BB_COLD_PARTITION |
8d672d12 | 886 | || probably_never_executed_bb_p (cfun, bb)) |
674f7a9c | 887 | return BB_FREQ_MAX; |
888 | ||
889 | /* Prefer blocks whose predecessor is an end of some trace | |
890 | or whose predecessor edge is EDGE_DFS_BACK. */ | |
cd665a06 | 891 | FOR_EACH_EDGE (e, ei, bb->preds) |
65f34de5 | 892 | { |
34154e27 | 893 | if ((e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
894 | && bbd[e->src->index].end_of_trace >= 0) | |
674f7a9c | 895 | || (e->flags & EDGE_DFS_BACK)) |
896 | { | |
897 | int edge_freq = EDGE_FREQUENCY (e); | |
898 | ||
899 | if (edge_freq > priority) | |
900 | priority = edge_freq; | |
901 | } | |
65f34de5 | 902 | } |
a6540cbf | 903 | |
674f7a9c | 904 | if (priority) |
905 | /* The block with priority should have significantly lower key. */ | |
906 | return -(100 * BB_FREQ_MAX + 100 * priority + bb->frequency); | |
b2f6568f | 907 | |
674f7a9c | 908 | return -bb->frequency; |
909 | } | |
910 | ||
911 | /* Return true when the edge E from basic block BB is better than the temporary | |
912 | best edge (details are in function). The probability of edge E is PROB. The | |
913 | frequency of the successor is FREQ. The current best probability is | |
914 | BEST_PROB, the best frequency is BEST_FREQ. | |
915 | The edge is considered to be equivalent when PROB does not differ much from | |
916 | BEST_PROB; similarly for frequency. */ | |
917 | ||
918 | static bool | |
b2f6568f | 919 | better_edge_p (const_basic_block bb, const_edge e, int prob, int freq, |
920 | int best_prob, int best_freq, const_edge cur_best_edge) | |
674f7a9c | 921 | { |
922 | bool is_better_edge; | |
075d20cf | 923 | |
674f7a9c | 924 | /* The BEST_* values do not have to be best, but can be a bit smaller than |
925 | maximum values. */ | |
926 | int diff_prob = best_prob / 10; | |
927 | int diff_freq = best_freq / 10; | |
075d20cf | 928 | |
e0b377e0 | 929 | /* The smaller one is better to keep the original order. */ |
930 | if (optimize_function_for_size_p (cfun)) | |
931 | return !cur_best_edge | |
932 | || cur_best_edge->dest->index > e->dest->index; | |
933 | ||
674f7a9c | 934 | if (prob > best_prob + diff_prob) |
935 | /* The edge has higher probability than the temporary best edge. */ | |
936 | is_better_edge = true; | |
937 | else if (prob < best_prob - diff_prob) | |
938 | /* The edge has lower probability than the temporary best edge. */ | |
939 | is_better_edge = false; | |
940 | else if (freq < best_freq - diff_freq) | |
941 | /* The edge and the temporary best edge have almost equivalent | |
942 | probabilities. The higher frequency of a successor now means | |
943 | that there is another edge going into that successor. | |
944 | This successor has lower frequency so it is better. */ | |
945 | is_better_edge = true; | |
946 | else if (freq > best_freq + diff_freq) | |
947 | /* This successor has higher frequency so it is worse. */ | |
948 | is_better_edge = false; | |
949 | else if (e->dest->prev_bb == bb) | |
950 | /* The edges have equivalent probabilities and the successors | |
951 | have equivalent frequencies. Select the previous successor. */ | |
952 | is_better_edge = true; | |
953 | else | |
954 | is_better_edge = false; | |
955 | ||
4f18499c | 956 | /* If we are doing hot/cold partitioning, make sure that we always favor |
957 | non-crossing edges over crossing edges. */ | |
958 | ||
959 | if (!is_better_edge | |
a0c938f0 | 960 | && flag_reorder_blocks_and_partition |
961 | && cur_best_edge | |
9858d888 | 962 | && (cur_best_edge->flags & EDGE_CROSSING) |
963 | && !(e->flags & EDGE_CROSSING)) | |
4f18499c | 964 | is_better_edge = true; |
965 | ||
674f7a9c | 966 | return is_better_edge; |
967 | } | |
968 | ||
e0b377e0 | 969 | /* Return true when the edge E is better than the temporary best edge |
970 | CUR_BEST_EDGE. If SRC_INDEX_P is true, the function compares the src bb of | |
971 | E and CUR_BEST_EDGE; otherwise it will compare the dest bb. | |
972 | BEST_LEN is the trace length of src (or dest) bb in CUR_BEST_EDGE. | |
973 | TRACES record the information about traces. | |
974 | When optimizing for size, the edge with smaller index is better. | |
975 | When optimizing for speed, the edge with bigger probability or longer trace | |
976 | is better. */ | |
977 | ||
978 | static bool | |
979 | connect_better_edge_p (const_edge e, bool src_index_p, int best_len, | |
980 | const_edge cur_best_edge, struct trace *traces) | |
981 | { | |
982 | int e_index; | |
983 | int b_index; | |
984 | bool is_better_edge; | |
985 | ||
986 | if (!cur_best_edge) | |
987 | return true; | |
988 | ||
989 | if (optimize_function_for_size_p (cfun)) | |
990 | { | |
991 | e_index = src_index_p ? e->src->index : e->dest->index; | |
992 | b_index = src_index_p ? cur_best_edge->src->index | |
993 | : cur_best_edge->dest->index; | |
994 | /* The smaller one is better to keep the original order. */ | |
995 | return b_index > e_index; | |
996 | } | |
997 | ||
998 | if (src_index_p) | |
999 | { | |
1000 | e_index = e->src->index; | |
1001 | ||
1002 | if (e->probability > cur_best_edge->probability) | |
1003 | /* The edge has higher probability than the temporary best edge. */ | |
1004 | is_better_edge = true; | |
1005 | else if (e->probability < cur_best_edge->probability) | |
1006 | /* The edge has lower probability than the temporary best edge. */ | |
1007 | is_better_edge = false; | |
1008 | else if (traces[bbd[e_index].end_of_trace].length > best_len) | |
1009 | /* The edge and the temporary best edge have equivalent probabilities. | |
1010 | The edge with longer trace is better. */ | |
1011 | is_better_edge = true; | |
1012 | else | |
1013 | is_better_edge = false; | |
1014 | } | |
1015 | else | |
1016 | { | |
1017 | e_index = e->dest->index; | |
1018 | ||
1019 | if (e->probability > cur_best_edge->probability) | |
1020 | /* The edge has higher probability than the temporary best edge. */ | |
1021 | is_better_edge = true; | |
1022 | else if (e->probability < cur_best_edge->probability) | |
1023 | /* The edge has lower probability than the temporary best edge. */ | |
1024 | is_better_edge = false; | |
1025 | else if (traces[bbd[e_index].start_of_trace].length > best_len) | |
1026 | /* The edge and the temporary best edge have equivalent probabilities. | |
1027 | The edge with longer trace is better. */ | |
1028 | is_better_edge = true; | |
1029 | else | |
1030 | is_better_edge = false; | |
1031 | } | |
1032 | ||
1033 | return is_better_edge; | |
1034 | } | |
1035 | ||
674f7a9c | 1036 | /* Connect traces in array TRACES, N_TRACES is the count of traces. */ |
1037 | ||
1038 | static void | |
aecda0d6 | 1039 | connect_traces (int n_traces, struct trace *traces) |
674f7a9c | 1040 | { |
1041 | int i; | |
1042 | bool *connected; | |
1897b881 | 1043 | bool two_passes; |
674f7a9c | 1044 | int last_trace; |
1897b881 | 1045 | int current_pass; |
1046 | int current_partition; | |
674f7a9c | 1047 | int freq_threshold; |
1048 | gcov_type count_threshold; | |
e0b377e0 | 1049 | bool for_size = optimize_function_for_size_p (cfun); |
674f7a9c | 1050 | |
1051 | freq_threshold = max_entry_frequency * DUPLICATION_THRESHOLD / 1000; | |
1052 | if (max_entry_count < INT_MAX / 1000) | |
1053 | count_threshold = max_entry_count * DUPLICATION_THRESHOLD / 1000; | |
1054 | else | |
1055 | count_threshold = max_entry_count / 1000 * DUPLICATION_THRESHOLD; | |
1056 | ||
4c36ffe6 | 1057 | connected = XCNEWVEC (bool, n_traces); |
674f7a9c | 1058 | last_trace = -1; |
1897b881 | 1059 | current_pass = 1; |
1060 | current_partition = BB_PARTITION (traces[0].first); | |
1061 | two_passes = false; | |
4f18499c | 1062 | |
812ca88e | 1063 | if (crtl->has_bb_partition) |
1897b881 | 1064 | for (i = 0; i < n_traces && !two_passes; i++) |
a0c938f0 | 1065 | if (BB_PARTITION (traces[0].first) |
1897b881 | 1066 | != BB_PARTITION (traces[i].first)) |
1067 | two_passes = true; | |
1068 | ||
1069 | for (i = 0; i < n_traces || (two_passes && current_pass == 1) ; i++) | |
a6540cbf | 1070 | { |
674f7a9c | 1071 | int t = i; |
1072 | int t2; | |
1073 | edge e, best; | |
1074 | int best_len; | |
a6540cbf | 1075 | |
1897b881 | 1076 | if (i >= n_traces) |
4f18499c | 1077 | { |
a53ff4c1 | 1078 | gcc_assert (two_passes && current_pass == 1); |
1079 | i = 0; | |
1080 | t = i; | |
1081 | current_pass = 2; | |
1082 | if (current_partition == BB_HOT_PARTITION) | |
1083 | current_partition = BB_COLD_PARTITION; | |
1897b881 | 1084 | else |
a53ff4c1 | 1085 | current_partition = BB_HOT_PARTITION; |
4f18499c | 1086 | } |
a0c938f0 | 1087 | |
674f7a9c | 1088 | if (connected[t]) |
1089 | continue; | |
075d20cf | 1090 | |
a0c938f0 | 1091 | if (two_passes |
1897b881 | 1092 | && BB_PARTITION (traces[t].first) != current_partition) |
1093 | continue; | |
1094 | ||
674f7a9c | 1095 | connected[t] = true; |
5dac3693 | 1096 | |
674f7a9c | 1097 | /* Find the predecessor traces. */ |
1098 | for (t2 = t; t2 > 0;) | |
1099 | { | |
cd665a06 | 1100 | edge_iterator ei; |
674f7a9c | 1101 | best = NULL; |
1102 | best_len = 0; | |
cd665a06 | 1103 | FOR_EACH_EDGE (e, ei, traces[t2].first->preds) |
674f7a9c | 1104 | { |
1105 | int si = e->src->index; | |
5dac3693 | 1106 | |
34154e27 | 1107 | if (e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
674f7a9c | 1108 | && (e->flags & EDGE_CAN_FALLTHRU) |
1109 | && !(e->flags & EDGE_COMPLEX) | |
1110 | && bbd[si].end_of_trace >= 0 | |
1111 | && !connected[bbd[si].end_of_trace] | |
1897b881 | 1112 | && (BB_PARTITION (e->src) == current_partition) |
e0b377e0 | 1113 | && connect_better_edge_p (e, true, best_len, best, traces)) |
674f7a9c | 1114 | { |
1115 | best = e; | |
1116 | best_len = traces[bbd[si].end_of_trace].length; | |
1117 | } | |
1118 | } | |
1119 | if (best) | |
1120 | { | |
bc5f266a | 1121 | best->src->aux = best->dest; |
674f7a9c | 1122 | t2 = bbd[best->src->index].end_of_trace; |
1123 | connected[t2] = true; | |
4f18499c | 1124 | |
450d042a | 1125 | if (dump_file) |
674f7a9c | 1126 | { |
450d042a | 1127 | fprintf (dump_file, "Connection: %d %d\n", |
674f7a9c | 1128 | best->src->index, best->dest->index); |
1129 | } | |
1130 | } | |
1131 | else | |
1132 | break; | |
1133 | } | |
075d20cf | 1134 | |
674f7a9c | 1135 | if (last_trace >= 0) |
bc5f266a | 1136 | traces[last_trace].last->aux = traces[t2].first; |
674f7a9c | 1137 | last_trace = t; |
1138 | ||
1139 | /* Find the successor traces. */ | |
1140 | while (1) | |
5dac3693 | 1141 | { |
674f7a9c | 1142 | /* Find the continuation of the chain. */ |
cd665a06 | 1143 | edge_iterator ei; |
674f7a9c | 1144 | best = NULL; |
1145 | best_len = 0; | |
cd665a06 | 1146 | FOR_EACH_EDGE (e, ei, traces[t].last->succs) |
674f7a9c | 1147 | { |
1148 | int di = e->dest->index; | |
1149 | ||
34154e27 | 1150 | if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun) |
674f7a9c | 1151 | && (e->flags & EDGE_CAN_FALLTHRU) |
1152 | && !(e->flags & EDGE_COMPLEX) | |
1153 | && bbd[di].start_of_trace >= 0 | |
1154 | && !connected[bbd[di].start_of_trace] | |
1897b881 | 1155 | && (BB_PARTITION (e->dest) == current_partition) |
e0b377e0 | 1156 | && connect_better_edge_p (e, false, best_len, best, traces)) |
674f7a9c | 1157 | { |
1158 | best = e; | |
1159 | best_len = traces[bbd[di].start_of_trace].length; | |
1160 | } | |
1161 | } | |
1162 | ||
e0b377e0 | 1163 | if (for_size) |
1164 | { | |
1165 | if (!best) | |
1166 | /* Stop finding the successor traces. */ | |
1167 | break; | |
1168 | ||
1169 | /* It is OK to connect block n with block n + 1 or a block | |
1170 | before n. For others, only connect to the loop header. */ | |
1171 | if (best->dest->index > (traces[t].last->index + 1)) | |
1172 | { | |
1173 | int count = EDGE_COUNT (best->dest->preds); | |
1174 | ||
1175 | FOR_EACH_EDGE (e, ei, best->dest->preds) | |
1176 | if (e->flags & EDGE_DFS_BACK) | |
1177 | count--; | |
1178 | ||
1179 | /* If dest has multiple predecessors, skip it. We expect | |
1180 | that one predecessor with smaller index connects with it | |
1181 | later. */ | |
1182 | if (count != 1) | |
1183 | break; | |
1184 | } | |
1185 | ||
1186 | /* Only connect Trace n with Trace n + 1. It is conservative | |
1187 | to keep the order as close as possible to the original order. | |
1188 | It also helps to reduce long jumps. */ | |
1189 | if (last_trace != bbd[best->dest->index].start_of_trace - 1) | |
1190 | break; | |
1191 | ||
1192 | if (dump_file) | |
1193 | fprintf (dump_file, "Connection: %d %d\n", | |
1194 | best->src->index, best->dest->index); | |
1195 | ||
1196 | t = bbd[best->dest->index].start_of_trace; | |
1197 | traces[last_trace].last->aux = traces[t].first; | |
1198 | connected[t] = true; | |
1199 | last_trace = t; | |
1200 | } | |
1201 | else if (best) | |
674f7a9c | 1202 | { |
450d042a | 1203 | if (dump_file) |
674f7a9c | 1204 | { |
450d042a | 1205 | fprintf (dump_file, "Connection: %d %d\n", |
674f7a9c | 1206 | best->src->index, best->dest->index); |
1207 | } | |
1208 | t = bbd[best->dest->index].start_of_trace; | |
bc5f266a | 1209 | traces[last_trace].last->aux = traces[t].first; |
674f7a9c | 1210 | connected[t] = true; |
1211 | last_trace = t; | |
1212 | } | |
1213 | else | |
1214 | { | |
1215 | /* Try to connect the traces by duplication of 1 block. */ | |
1216 | edge e2; | |
1217 | basic_block next_bb = NULL; | |
cea5721f | 1218 | bool try_copy = false; |
674f7a9c | 1219 | |
cd665a06 | 1220 | FOR_EACH_EDGE (e, ei, traces[t].last->succs) |
34154e27 | 1221 | if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun) |
674f7a9c | 1222 | && (e->flags & EDGE_CAN_FALLTHRU) |
1223 | && !(e->flags & EDGE_COMPLEX) | |
cea5721f | 1224 | && (!best || e->probability > best->probability)) |
674f7a9c | 1225 | { |
cd665a06 | 1226 | edge_iterator ei; |
674f7a9c | 1227 | edge best2 = NULL; |
1228 | int best2_len = 0; | |
1229 | ||
d5ade7f4 | 1230 | /* If the destination is a start of a trace which is only |
1231 | one block long, then no need to search the successor | |
cea5721f | 1232 | blocks of the trace. Accept it. */ |
d5ade7f4 | 1233 | if (bbd[e->dest->index].start_of_trace >= 0 |
1234 | && traces[bbd[e->dest->index].start_of_trace].length | |
1235 | == 1) | |
1236 | { | |
1237 | best = e; | |
1238 | try_copy = true; | |
1239 | continue; | |
1240 | } | |
cea5721f | 1241 | |
cd665a06 | 1242 | FOR_EACH_EDGE (e2, ei, e->dest->succs) |
674f7a9c | 1243 | { |
1244 | int di = e2->dest->index; | |
1245 | ||
34154e27 | 1246 | if (e2->dest == EXIT_BLOCK_PTR_FOR_FN (cfun) |
674f7a9c | 1247 | || ((e2->flags & EDGE_CAN_FALLTHRU) |
1248 | && !(e2->flags & EDGE_COMPLEX) | |
1249 | && bbd[di].start_of_trace >= 0 | |
1250 | && !connected[bbd[di].start_of_trace] | |
b2f6568f | 1251 | && BB_PARTITION (e2->dest) == current_partition |
1252 | && EDGE_FREQUENCY (e2) >= freq_threshold | |
1253 | && e2->count >= count_threshold | |
674f7a9c | 1254 | && (!best2 |
1255 | || e2->probability > best2->probability | |
1256 | || (e2->probability == best2->probability | |
1257 | && traces[bbd[di].start_of_trace].length | |
1258 | > best2_len)))) | |
1259 | { | |
1260 | best = e; | |
1261 | best2 = e2; | |
34154e27 | 1262 | if (e2->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
674f7a9c | 1263 | best2_len = traces[bbd[di].start_of_trace].length; |
1264 | else | |
1265 | best2_len = INT_MAX; | |
1266 | next_bb = e2->dest; | |
cea5721f | 1267 | try_copy = true; |
674f7a9c | 1268 | } |
1269 | } | |
1270 | } | |
cea5721f | 1271 | |
812ca88e | 1272 | if (crtl->has_bb_partition) |
4f18499c | 1273 | try_copy = false; |
1274 | ||
cea5721f | 1275 | /* Copy tiny blocks always; copy larger blocks only when the |
1276 | edge is traversed frequently enough. */ | |
1277 | if (try_copy | |
1278 | && copy_bb_p (best->dest, | |
0bfd8d5c | 1279 | optimize_edge_for_speed_p (best) |
cea5721f | 1280 | && EDGE_FREQUENCY (best) >= freq_threshold |
1281 | && best->count >= count_threshold)) | |
674f7a9c | 1282 | { |
1283 | basic_block new_bb; | |
1284 | ||
450d042a | 1285 | if (dump_file) |
674f7a9c | 1286 | { |
450d042a | 1287 | fprintf (dump_file, "Connection: %d %d ", |
674f7a9c | 1288 | traces[t].last->index, best->dest->index); |
cea5721f | 1289 | if (!next_bb) |
450d042a | 1290 | fputc ('\n', dump_file); |
34154e27 | 1291 | else if (next_bb == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
450d042a | 1292 | fprintf (dump_file, "exit\n"); |
674f7a9c | 1293 | else |
450d042a | 1294 | fprintf (dump_file, "%d\n", next_bb->index); |
674f7a9c | 1295 | } |
1296 | ||
1297 | new_bb = copy_bb (best->dest, best, traces[t].last, t); | |
1298 | traces[t].last = new_bb; | |
34154e27 | 1299 | if (next_bb && next_bb != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
674f7a9c | 1300 | { |
1301 | t = bbd[next_bb->index].start_of_trace; | |
bc5f266a | 1302 | traces[last_trace].last->aux = traces[t].first; |
674f7a9c | 1303 | connected[t] = true; |
1304 | last_trace = t; | |
1305 | } | |
1306 | else | |
1307 | break; /* Stop finding the successor traces. */ | |
1308 | } | |
1309 | else | |
1310 | break; /* Stop finding the successor traces. */ | |
1311 | } | |
5dac3693 | 1312 | } |
674f7a9c | 1313 | } |
1314 | ||
450d042a | 1315 | if (dump_file) |
674f7a9c | 1316 | { |
1317 | basic_block bb; | |
075d20cf | 1318 | |
450d042a | 1319 | fprintf (dump_file, "Final order:\n"); |
364c0c59 | 1320 | for (bb = traces[0].first; bb; bb = (basic_block) bb->aux) |
450d042a | 1321 | fprintf (dump_file, "%d ", bb->index); |
1322 | fprintf (dump_file, "\n"); | |
1323 | fflush (dump_file); | |
a6540cbf | 1324 | } |
1325 | ||
674f7a9c | 1326 | FREE (connected); |
1327 | } | |
1328 | ||
1329 | /* Return true when BB can and should be copied. CODE_MAY_GROW is true | |
1330 | when code size is allowed to grow by duplication. */ | |
1331 | ||
1332 | static bool | |
5493cb9a | 1333 | copy_bb_p (const_basic_block bb, int code_may_grow) |
674f7a9c | 1334 | { |
1335 | int size = 0; | |
1336 | int max_size = uncond_jump_length; | |
867177a5 | 1337 | rtx_insn *insn; |
674f7a9c | 1338 | |
1339 | if (!bb->frequency) | |
1340 | return false; | |
cd665a06 | 1341 | if (EDGE_COUNT (bb->preds) < 2) |
674f7a9c | 1342 | return false; |
4ee9c684 | 1343 | if (!can_duplicate_block_p (bb)) |
674f7a9c | 1344 | return false; |
1345 | ||
bc8dca6f | 1346 | /* Avoid duplicating blocks which have many successors (PR/13430). */ |
cd665a06 | 1347 | if (EDGE_COUNT (bb->succs) > 8) |
1348 | return false; | |
bc8dca6f | 1349 | |
0bfd8d5c | 1350 | if (code_may_grow && optimize_bb_for_speed_p (bb)) |
6b6a2169 | 1351 | max_size *= PARAM_VALUE (PARAM_MAX_GROW_COPY_BB_INSNS); |
674f7a9c | 1352 | |
b70a5a99 | 1353 | FOR_BB_INSNS (bb, insn) |
075d20cf | 1354 | { |
674f7a9c | 1355 | if (INSN_P (insn)) |
16afa8ae | 1356 | size += get_attr_min_length (insn); |
075d20cf | 1357 | } |
a6540cbf | 1358 | |
674f7a9c | 1359 | if (size <= max_size) |
1360 | return true; | |
1361 | ||
450d042a | 1362 | if (dump_file) |
075d20cf | 1363 | { |
450d042a | 1364 | fprintf (dump_file, |
674f7a9c | 1365 | "Block %d can't be copied because its size = %d.\n", |
1366 | bb->index, size); | |
075d20cf | 1367 | } |
a6540cbf | 1368 | |
674f7a9c | 1369 | return false; |
1370 | } | |
1371 | ||
1372 | /* Return the length of unconditional jump instruction. */ | |
1373 | ||
0a55d497 | 1374 | int |
aecda0d6 | 1375 | get_uncond_jump_length (void) |
674f7a9c | 1376 | { |
674f7a9c | 1377 | int length; |
1378 | ||
56cc2429 | 1379 | start_sequence (); |
9ed997be | 1380 | rtx_code_label *label = emit_label (gen_label_rtx ()); |
1d5ad681 | 1381 | rtx_insn *jump = emit_jump_insn (targetm.gen_jump (label)); |
16afa8ae | 1382 | length = get_attr_min_length (jump); |
56cc2429 | 1383 | end_sequence (); |
674f7a9c | 1384 | |
674f7a9c | 1385 | return length; |
a6540cbf | 1386 | } |
1387 | ||
f59cbcbf | 1388 | /* The landing pad OLD_LP, in block OLD_BB, has edges from both partitions. |
1389 | Duplicate the landing pad and split the edges so that no EH edge | |
1390 | crosses partitions. */ | |
1391 | ||
1392 | static void | |
1393 | fix_up_crossing_landing_pad (eh_landing_pad old_lp, basic_block old_bb) | |
1394 | { | |
1395 | eh_landing_pad new_lp; | |
1396 | basic_block new_bb, last_bb, post_bb; | |
9ed997be | 1397 | rtx_insn *jump; |
f59cbcbf | 1398 | unsigned new_partition; |
1399 | edge_iterator ei; | |
1400 | edge e; | |
1401 | ||
1402 | /* Generate the new landing-pad structure. */ | |
1403 | new_lp = gen_eh_landing_pad (old_lp->region); | |
1404 | new_lp->post_landing_pad = old_lp->post_landing_pad; | |
1405 | new_lp->landing_pad = gen_label_rtx (); | |
1406 | LABEL_PRESERVE_P (new_lp->landing_pad) = 1; | |
1407 | ||
1408 | /* Put appropriate instructions in new bb. */ | |
9ed997be | 1409 | rtx_code_label *new_label = emit_label (new_lp->landing_pad); |
f59cbcbf | 1410 | |
1411 | expand_dw2_landing_pad_for_region (old_lp->region); | |
1412 | ||
1413 | post_bb = BLOCK_FOR_INSN (old_lp->landing_pad); | |
1414 | post_bb = single_succ (post_bb); | |
9ed997be | 1415 | rtx_code_label *post_label = block_label (post_bb); |
1d5ad681 | 1416 | jump = emit_jump_insn (targetm.gen_jump (post_label)); |
f59cbcbf | 1417 | JUMP_LABEL (jump) = post_label; |
1418 | ||
1419 | /* Create new basic block to be dest for lp. */ | |
34154e27 | 1420 | last_bb = EXIT_BLOCK_PTR_FOR_FN (cfun)->prev_bb; |
f59cbcbf | 1421 | new_bb = create_basic_block (new_label, jump, last_bb); |
1422 | new_bb->aux = last_bb->aux; | |
1423 | last_bb->aux = new_bb; | |
1424 | ||
1425 | emit_barrier_after_bb (new_bb); | |
1426 | ||
1427 | make_edge (new_bb, post_bb, 0); | |
1428 | ||
1429 | /* Make sure new bb is in the other partition. */ | |
1430 | new_partition = BB_PARTITION (old_bb); | |
1431 | new_partition ^= BB_HOT_PARTITION | BB_COLD_PARTITION; | |
1432 | BB_SET_PARTITION (new_bb, new_partition); | |
1433 | ||
1434 | /* Fix up the edges. */ | |
1435 | for (ei = ei_start (old_bb->preds); (e = ei_safe_edge (ei)) != NULL; ) | |
1436 | if (BB_PARTITION (e->src) == new_partition) | |
1437 | { | |
867177a5 | 1438 | rtx_insn *insn = BB_END (e->src); |
f59cbcbf | 1439 | rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX); |
1440 | ||
1441 | gcc_assert (note != NULL); | |
1442 | gcc_checking_assert (INTVAL (XEXP (note, 0)) == old_lp->index); | |
1443 | XEXP (note, 0) = GEN_INT (new_lp->index); | |
1444 | ||
1445 | /* Adjust the edge to the new destination. */ | |
1446 | redirect_edge_succ (e, new_bb); | |
1447 | } | |
1448 | else | |
1449 | ei_next (&ei); | |
1450 | } | |
1451 | ||
80adc5a6 | 1452 | |
1453 | /* Ensure that all hot bbs are included in a hot path through the | |
1454 | procedure. This is done by calling this function twice, once | |
1455 | with WALK_UP true (to look for paths from the entry to hot bbs) and | |
1456 | once with WALK_UP false (to look for paths from hot bbs to the exit). | |
1457 | Returns the updated value of COLD_BB_COUNT and adds newly-hot bbs | |
1458 | to BBS_IN_HOT_PARTITION. */ | |
1459 | ||
1460 | static unsigned int | |
1461 | sanitize_hot_paths (bool walk_up, unsigned int cold_bb_count, | |
1462 | vec<basic_block> *bbs_in_hot_partition) | |
1463 | { | |
1464 | /* Callers check this. */ | |
1465 | gcc_checking_assert (cold_bb_count); | |
1466 | ||
1467 | /* Keep examining hot bbs while we still have some left to check | |
1468 | and there are remaining cold bbs. */ | |
1469 | vec<basic_block> hot_bbs_to_check = bbs_in_hot_partition->copy (); | |
1470 | while (! hot_bbs_to_check.is_empty () | |
1471 | && cold_bb_count) | |
1472 | { | |
1473 | basic_block bb = hot_bbs_to_check.pop (); | |
1474 | vec<edge, va_gc> *edges = walk_up ? bb->preds : bb->succs; | |
1475 | edge e; | |
1476 | edge_iterator ei; | |
1477 | int highest_probability = 0; | |
1478 | int highest_freq = 0; | |
1479 | gcov_type highest_count = 0; | |
1480 | bool found = false; | |
1481 | ||
1482 | /* Walk the preds/succs and check if there is at least one already | |
1483 | marked hot. Keep track of the most frequent pred/succ so that we | |
1484 | can mark it hot if we don't find one. */ | |
1485 | FOR_EACH_EDGE (e, ei, edges) | |
1486 | { | |
1487 | basic_block reach_bb = walk_up ? e->src : e->dest; | |
1488 | ||
1489 | if (e->flags & EDGE_DFS_BACK) | |
1490 | continue; | |
1491 | ||
1492 | if (BB_PARTITION (reach_bb) != BB_COLD_PARTITION) | |
1493 | { | |
1494 | found = true; | |
1495 | break; | |
1496 | } | |
1497 | /* The following loop will look for the hottest edge via | |
1498 | the edge count, if it is non-zero, then fallback to the edge | |
1499 | frequency and finally the edge probability. */ | |
1500 | if (e->count > highest_count) | |
1501 | highest_count = e->count; | |
1502 | int edge_freq = EDGE_FREQUENCY (e); | |
1503 | if (edge_freq > highest_freq) | |
1504 | highest_freq = edge_freq; | |
1505 | if (e->probability > highest_probability) | |
1506 | highest_probability = e->probability; | |
1507 | } | |
1508 | ||
1509 | /* If bb is reached by (or reaches, in the case of !WALK_UP) another hot | |
1510 | block (or unpartitioned, e.g. the entry block) then it is ok. If not, | |
1511 | then the most frequent pred (or succ) needs to be adjusted. In the | |
1512 | case where multiple preds/succs have the same frequency (e.g. a | |
1513 | 50-50 branch), then both will be adjusted. */ | |
1514 | if (found) | |
1515 | continue; | |
1516 | ||
1517 | FOR_EACH_EDGE (e, ei, edges) | |
1518 | { | |
1519 | if (e->flags & EDGE_DFS_BACK) | |
1520 | continue; | |
1521 | /* Select the hottest edge using the edge count, if it is non-zero, | |
1522 | then fallback to the edge frequency and finally the edge | |
1523 | probability. */ | |
1524 | if (highest_count) | |
1525 | { | |
1526 | if (e->count < highest_count) | |
1527 | continue; | |
1528 | } | |
1529 | else if (highest_freq) | |
1530 | { | |
1531 | if (EDGE_FREQUENCY (e) < highest_freq) | |
1532 | continue; | |
1533 | } | |
1534 | else if (e->probability < highest_probability) | |
1535 | continue; | |
1536 | ||
1537 | basic_block reach_bb = walk_up ? e->src : e->dest; | |
1538 | ||
1539 | /* We have a hot bb with an immediate dominator that is cold. | |
1540 | The dominator needs to be re-marked hot. */ | |
1541 | BB_SET_PARTITION (reach_bb, BB_HOT_PARTITION); | |
1542 | cold_bb_count--; | |
1543 | ||
1544 | /* Now we need to examine newly-hot reach_bb to see if it is also | |
1545 | dominated by a cold bb. */ | |
1546 | bbs_in_hot_partition->safe_push (reach_bb); | |
1547 | hot_bbs_to_check.safe_push (reach_bb); | |
1548 | } | |
1549 | } | |
1550 | ||
1551 | return cold_bb_count; | |
1552 | } | |
1553 | ||
1554 | ||
4f18499c | 1555 | /* Find the basic blocks that are rarely executed and need to be moved to |
1556 | a separate section of the .o file (to cut down on paging and improve | |
2a8e5eeb | 1557 | cache locality). Return a vector of all edges that cross. */ |
4f18499c | 1558 | |
80adc5a6 | 1559 | static vec<edge> |
2a8e5eeb | 1560 | find_rarely_executed_basic_blocks_and_crossing_edges (void) |
4f18499c | 1561 | { |
1e094109 | 1562 | vec<edge> crossing_edges = vNULL; |
4f18499c | 1563 | basic_block bb; |
1564 | edge e; | |
cd665a06 | 1565 | edge_iterator ei; |
80adc5a6 | 1566 | unsigned int cold_bb_count = 0; |
deeafd45 | 1567 | auto_vec<basic_block> bbs_in_hot_partition; |
4f18499c | 1568 | |
1569 | /* Mark which partition (hot/cold) each basic block belongs in. */ | |
fc00614f | 1570 | FOR_EACH_BB_FN (bb, cfun) |
4f18499c | 1571 | { |
dcc9b351 | 1572 | bool cold_bb = false; |
1573 | ||
8d672d12 | 1574 | if (probably_never_executed_bb_p (cfun, bb)) |
dcc9b351 | 1575 | { |
1576 | /* Handle profile insanities created by upstream optimizations | |
1577 | by also checking the incoming edge weights. If there is a non-cold | |
1578 | incoming edge, conservatively prevent this block from being split | |
1579 | into the cold section. */ | |
1580 | cold_bb = true; | |
1581 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1582 | if (!probably_never_executed_edge_p (cfun, e)) | |
1583 | { | |
1584 | cold_bb = false; | |
1585 | break; | |
1586 | } | |
1587 | } | |
1588 | if (cold_bb) | |
80adc5a6 | 1589 | { |
1590 | BB_SET_PARTITION (bb, BB_COLD_PARTITION); | |
1591 | cold_bb_count++; | |
1592 | } | |
4f18499c | 1593 | else |
80adc5a6 | 1594 | { |
1595 | BB_SET_PARTITION (bb, BB_HOT_PARTITION); | |
1596 | bbs_in_hot_partition.safe_push (bb); | |
1597 | } | |
1598 | } | |
1599 | ||
1600 | /* Ensure that hot bbs are included along a hot path from the entry to exit. | |
1601 | Several different possibilities may include cold bbs along all paths | |
1602 | to/from a hot bb. One is that there are edge weight insanities | |
1603 | due to optimization phases that do not properly update basic block profile | |
1604 | counts. The second is that the entry of the function may not be hot, because | |
1605 | it is entered fewer times than the number of profile training runs, but there | |
1606 | is a loop inside the function that causes blocks within the function to be | |
1607 | above the threshold for hotness. This is fixed by walking up from hot bbs | |
1608 | to the entry block, and then down from hot bbs to the exit, performing | |
1609 | partitioning fixups as necessary. */ | |
1610 | if (cold_bb_count) | |
1611 | { | |
1612 | mark_dfs_back_edges (); | |
1613 | cold_bb_count = sanitize_hot_paths (true, cold_bb_count, | |
1614 | &bbs_in_hot_partition); | |
1615 | if (cold_bb_count) | |
1616 | sanitize_hot_paths (false, cold_bb_count, &bbs_in_hot_partition); | |
4f18499c | 1617 | } |
1618 | ||
f59cbcbf | 1619 | /* The format of .gcc_except_table does not allow landing pads to |
1620 | be in a different partition as the throw. Fix this by either | |
1621 | moving or duplicating the landing pads. */ | |
1622 | if (cfun->eh->lp_array) | |
065efcb1 | 1623 | { |
f59cbcbf | 1624 | unsigned i; |
1625 | eh_landing_pad lp; | |
1626 | ||
f1f41a6c | 1627 | FOR_EACH_VEC_ELT (*cfun->eh->lp_array, i, lp) |
4d0e931f | 1628 | { |
f59cbcbf | 1629 | bool all_same, all_diff; |
1630 | ||
147f11a7 | 1631 | if (lp == NULL |
1632 | || lp->landing_pad == NULL_RTX | |
1633 | || !LABEL_P (lp->landing_pad)) | |
f59cbcbf | 1634 | continue; |
1635 | ||
1636 | all_same = all_diff = true; | |
1637 | bb = BLOCK_FOR_INSN (lp->landing_pad); | |
1638 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1639 | { | |
1640 | gcc_assert (e->flags & EDGE_EH); | |
1641 | if (BB_PARTITION (bb) == BB_PARTITION (e->src)) | |
1642 | all_diff = false; | |
1643 | else | |
1644 | all_same = false; | |
1645 | } | |
1646 | ||
1647 | if (all_same) | |
1648 | ; | |
1649 | else if (all_diff) | |
1650 | { | |
1651 | int which = BB_PARTITION (bb); | |
1652 | which ^= BB_HOT_PARTITION | BB_COLD_PARTITION; | |
1653 | BB_SET_PARTITION (bb, which); | |
1654 | } | |
1655 | else | |
1656 | fix_up_crossing_landing_pad (lp, bb); | |
4d0e931f | 1657 | } |
065efcb1 | 1658 | } |
2a8e5eeb | 1659 | |
f59cbcbf | 1660 | /* Mark every edge that crosses between sections. */ |
4f18499c | 1661 | |
fc00614f | 1662 | FOR_EACH_BB_FN (bb, cfun) |
f59cbcbf | 1663 | FOR_EACH_EDGE (e, ei, bb->succs) |
1664 | { | |
1665 | unsigned int flags = e->flags; | |
b2f6568f | 1666 | |
f59cbcbf | 1667 | /* We should never have EDGE_CROSSING set yet. */ |
1668 | gcc_checking_assert ((flags & EDGE_CROSSING) == 0); | |
1669 | ||
34154e27 | 1670 | if (e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
1671 | && e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun) | |
f59cbcbf | 1672 | && BB_PARTITION (e->src) != BB_PARTITION (e->dest)) |
1673 | { | |
f1f41a6c | 1674 | crossing_edges.safe_push (e); |
f59cbcbf | 1675 | flags |= EDGE_CROSSING; |
1676 | } | |
29211303 | 1677 | |
f59cbcbf | 1678 | /* Now that we've split eh edges as appropriate, allow landing pads |
1679 | to be merged with the post-landing pads. */ | |
1680 | flags &= ~EDGE_PRESERVE; | |
1681 | ||
1682 | e->flags = flags; | |
1683 | } | |
1684 | ||
1685 | return crossing_edges; | |
29211303 | 1686 | } |
1687 | ||
4a020a8c | 1688 | /* Set the flag EDGE_CAN_FALLTHRU for edges that can be fallthru. */ |
1689 | ||
1690 | static void | |
1691 | set_edge_can_fallthru_flag (void) | |
1692 | { | |
1693 | basic_block bb; | |
1694 | ||
fc00614f | 1695 | FOR_EACH_BB_FN (bb, cfun) |
4a020a8c | 1696 | { |
1697 | edge e; | |
1698 | edge_iterator ei; | |
1699 | ||
1700 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1701 | { | |
1702 | e->flags &= ~EDGE_CAN_FALLTHRU; | |
1703 | ||
1704 | /* The FALLTHRU edge is also CAN_FALLTHRU edge. */ | |
1705 | if (e->flags & EDGE_FALLTHRU) | |
1706 | e->flags |= EDGE_CAN_FALLTHRU; | |
1707 | } | |
1708 | ||
1709 | /* If the BB ends with an invertible condjump all (2) edges are | |
1710 | CAN_FALLTHRU edges. */ | |
1711 | if (EDGE_COUNT (bb->succs) != 2) | |
1712 | continue; | |
1713 | if (!any_condjump_p (BB_END (bb))) | |
1714 | continue; | |
f9a00e9e | 1715 | |
1716 | rtx_jump_insn *bb_end_jump = as_a <rtx_jump_insn *> (BB_END (bb)); | |
1717 | if (!invert_jump (bb_end_jump, JUMP_LABEL (bb_end_jump), 0)) | |
4a020a8c | 1718 | continue; |
f9a00e9e | 1719 | invert_jump (bb_end_jump, JUMP_LABEL (bb_end_jump), 0); |
4a020a8c | 1720 | EDGE_SUCC (bb, 0)->flags |= EDGE_CAN_FALLTHRU; |
1721 | EDGE_SUCC (bb, 1)->flags |= EDGE_CAN_FALLTHRU; | |
1722 | } | |
1723 | } | |
1724 | ||
4f18499c | 1725 | /* If any destination of a crossing edge does not have a label, add label; |
2a8e5eeb | 1726 | Convert any easy fall-through crossing edges to unconditional jumps. */ |
4f18499c | 1727 | |
a0c938f0 | 1728 | static void |
f1f41a6c | 1729 | add_labels_and_missing_jumps (vec<edge> crossing_edges) |
4f18499c | 1730 | { |
2a8e5eeb | 1731 | size_t i; |
1732 | edge e; | |
a0c938f0 | 1733 | |
f1f41a6c | 1734 | FOR_EACH_VEC_ELT (crossing_edges, i, e) |
4f18499c | 1735 | { |
2a8e5eeb | 1736 | basic_block src = e->src; |
1737 | basic_block dest = e->dest; | |
9ed997be | 1738 | rtx_jump_insn *new_jump; |
a0c938f0 | 1739 | |
34154e27 | 1740 | if (dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
2a8e5eeb | 1741 | continue; |
a0c938f0 | 1742 | |
2a8e5eeb | 1743 | /* Make sure dest has a label. */ |
9ed997be | 1744 | rtx_code_label *label = block_label (dest); |
a0c938f0 | 1745 | |
2a8e5eeb | 1746 | /* Nothing to do for non-fallthru edges. */ |
34154e27 | 1747 | if (src == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
2a8e5eeb | 1748 | continue; |
1749 | if ((e->flags & EDGE_FALLTHRU) == 0) | |
1750 | continue; | |
a0c938f0 | 1751 | |
2a8e5eeb | 1752 | /* If the block does not end with a control flow insn, then we |
1753 | can trivially add a jump to the end to fixup the crossing. | |
1754 | Otherwise the jump will have to go in a new bb, which will | |
1755 | be handled by fix_up_fall_thru_edges function. */ | |
1756 | if (control_flow_insn_p (BB_END (src))) | |
1757 | continue; | |
1758 | ||
1759 | /* Make sure there's only one successor. */ | |
1760 | gcc_assert (single_succ_p (src)); | |
1761 | ||
1d5ad681 | 1762 | new_jump = emit_jump_insn_after (targetm.gen_jump (label), BB_END (src)); |
26bb3cb2 | 1763 | BB_END (src) = new_jump; |
2a8e5eeb | 1764 | JUMP_LABEL (new_jump) = label; |
1765 | LABEL_NUSES (label) += 1; | |
29211303 | 1766 | |
1767 | emit_barrier_after_bb (src); | |
2a8e5eeb | 1768 | |
1769 | /* Mark edge as non-fallthru. */ | |
1770 | e->flags &= ~EDGE_FALLTHRU; | |
1771 | } | |
4f18499c | 1772 | } |
1773 | ||
1774 | /* Find any bb's where the fall-through edge is a crossing edge (note that | |
9cc5df33 | 1775 | these bb's must also contain a conditional jump or end with a call |
1776 | instruction; we've already dealt with fall-through edges for blocks | |
1777 | that didn't have a conditional jump or didn't end with call instruction | |
1778 | in the call to add_labels_and_missing_jumps). Convert the fall-through | |
1779 | edge to non-crossing edge by inserting a new bb to fall-through into. | |
1780 | The new bb will contain an unconditional jump (crossing edge) to the | |
1781 | original fall through destination. */ | |
4f18499c | 1782 | |
a0c938f0 | 1783 | static void |
4f18499c | 1784 | fix_up_fall_thru_edges (void) |
1785 | { | |
1786 | basic_block cur_bb; | |
1787 | basic_block new_bb; | |
1788 | edge succ1; | |
1789 | edge succ2; | |
1790 | edge fall_thru; | |
a3d80b23 | 1791 | edge cond_jump = NULL; |
4f18499c | 1792 | bool cond_jump_crosses; |
1793 | int invert_worked; | |
867177a5 | 1794 | rtx_insn *old_jump; |
9ed997be | 1795 | rtx_code_label *fall_thru_label; |
a0c938f0 | 1796 | |
fc00614f | 1797 | FOR_EACH_BB_FN (cur_bb, cfun) |
4f18499c | 1798 | { |
1799 | fall_thru = NULL; | |
cd665a06 | 1800 | if (EDGE_COUNT (cur_bb->succs) > 0) |
1801 | succ1 = EDGE_SUCC (cur_bb, 0); | |
1802 | else | |
1803 | succ1 = NULL; | |
1804 | ||
1805 | if (EDGE_COUNT (cur_bb->succs) > 1) | |
a0c938f0 | 1806 | succ2 = EDGE_SUCC (cur_bb, 1); |
4f18499c | 1807 | else |
a0c938f0 | 1808 | succ2 = NULL; |
1809 | ||
4f18499c | 1810 | /* Find the fall-through edge. */ |
a0c938f0 | 1811 | |
1812 | if (succ1 | |
1813 | && (succ1->flags & EDGE_FALLTHRU)) | |
1814 | { | |
1815 | fall_thru = succ1; | |
1816 | cond_jump = succ2; | |
1817 | } | |
1818 | else if (succ2 | |
1819 | && (succ2->flags & EDGE_FALLTHRU)) | |
1820 | { | |
1821 | fall_thru = succ2; | |
1822 | cond_jump = succ1; | |
1823 | } | |
ba59d457 | 1824 | else if (succ1 |
1825 | && (block_ends_with_call_p (cur_bb) | |
1826 | || can_throw_internal (BB_END (cur_bb)))) | |
1827 | { | |
1828 | edge e; | |
1829 | edge_iterator ei; | |
1830 | ||
ba59d457 | 1831 | FOR_EACH_EDGE (e, ei, cur_bb->succs) |
13858b08 | 1832 | if (e->flags & EDGE_FALLTHRU) |
ba59d457 | 1833 | { |
1834 | fall_thru = e; | |
1835 | break; | |
1836 | } | |
1837 | } | |
a0c938f0 | 1838 | |
34154e27 | 1839 | if (fall_thru && (fall_thru->dest != EXIT_BLOCK_PTR_FOR_FN (cfun))) |
a0c938f0 | 1840 | { |
1841 | /* Check to see if the fall-thru edge is a crossing edge. */ | |
1842 | ||
9858d888 | 1843 | if (fall_thru->flags & EDGE_CROSSING) |
a0c938f0 | 1844 | { |
4f18499c | 1845 | /* The fall_thru edge crosses; now check the cond jump edge, if |
a0c938f0 | 1846 | it exists. */ |
1847 | ||
1848 | cond_jump_crosses = true; | |
1849 | invert_worked = 0; | |
4f18499c | 1850 | old_jump = BB_END (cur_bb); |
a0c938f0 | 1851 | |
1852 | /* Find the jump instruction, if there is one. */ | |
1853 | ||
1854 | if (cond_jump) | |
1855 | { | |
9858d888 | 1856 | if (!(cond_jump->flags & EDGE_CROSSING)) |
a0c938f0 | 1857 | cond_jump_crosses = false; |
1858 | ||
1859 | /* We know the fall-thru edge crosses; if the cond | |
1860 | jump edge does NOT cross, and its destination is the | |
4f18499c | 1861 | next block in the bb order, invert the jump |
9d75589a | 1862 | (i.e. fix it so the fall through does not cross and |
a0c938f0 | 1863 | the cond jump does). */ |
1864 | ||
aa78dca5 | 1865 | if (!cond_jump_crosses) |
a0c938f0 | 1866 | { |
1867 | /* Find label in fall_thru block. We've already added | |
1868 | any missing labels, so there must be one. */ | |
1869 | ||
1870 | fall_thru_label = block_label (fall_thru->dest); | |
1871 | ||
f9a00e9e | 1872 | if (old_jump && fall_thru_label) |
1873 | { | |
1874 | rtx_jump_insn *old_jump_insn = | |
1875 | dyn_cast <rtx_jump_insn *> (old_jump); | |
1876 | if (old_jump_insn) | |
1877 | invert_worked = invert_jump (old_jump_insn, | |
1878 | fall_thru_label, 0); | |
1879 | } | |
1880 | ||
a0c938f0 | 1881 | if (invert_worked) |
1882 | { | |
1883 | fall_thru->flags &= ~EDGE_FALLTHRU; | |
1884 | cond_jump->flags |= EDGE_FALLTHRU; | |
1885 | update_br_prob_note (cur_bb); | |
dfcf26a5 | 1886 | std::swap (fall_thru, cond_jump); |
9858d888 | 1887 | cond_jump->flags |= EDGE_CROSSING; |
1888 | fall_thru->flags &= ~EDGE_CROSSING; | |
a0c938f0 | 1889 | } |
1890 | } | |
1891 | } | |
1892 | ||
1893 | if (cond_jump_crosses || !invert_worked) | |
1894 | { | |
1895 | /* This is the case where both edges out of the basic | |
1896 | block are crossing edges. Here we will fix up the | |
4f18499c | 1897 | fall through edge. The jump edge will be taken care |
48e1416a | 1898 | of later. The EDGE_CROSSING flag of fall_thru edge |
b2f6568f | 1899 | is unset before the call to force_nonfallthru |
1900 | function because if a new basic-block is created | |
1901 | this edge remains in the current section boundary | |
1902 | while the edge between new_bb and the fall_thru->dest | |
1903 | becomes EDGE_CROSSING. */ | |
9cc5df33 | 1904 | |
b2f6568f | 1905 | fall_thru->flags &= ~EDGE_CROSSING; |
a0c938f0 | 1906 | new_bb = force_nonfallthru (fall_thru); |
1907 | ||
1908 | if (new_bb) | |
1909 | { | |
1910 | new_bb->aux = cur_bb->aux; | |
1911 | cur_bb->aux = new_bb; | |
1912 | ||
aa78dca5 | 1913 | /* This is done by force_nonfallthru_and_redirect. */ |
1914 | gcc_assert (BB_PARTITION (new_bb) | |
1915 | == BB_PARTITION (cur_bb)); | |
7562ed74 | 1916 | |
ea091dfd | 1917 | single_succ_edge (new_bb)->flags |= EDGE_CROSSING; |
a0c938f0 | 1918 | } |
b2f6568f | 1919 | else |
1920 | { | |
1921 | /* If a new basic-block was not created; restore | |
1922 | the EDGE_CROSSING flag. */ | |
1923 | fall_thru->flags |= EDGE_CROSSING; | |
1924 | } | |
a0c938f0 | 1925 | |
1926 | /* Add barrier after new jump */ | |
29211303 | 1927 | emit_barrier_after_bb (new_bb ? new_bb : cur_bb); |
a0c938f0 | 1928 | } |
1929 | } | |
1930 | } | |
4f18499c | 1931 | } |
1932 | } | |
1933 | ||
f0b5f617 | 1934 | /* This function checks the destination block of a "crossing jump" to |
4f18499c | 1935 | see if it has any crossing predecessors that begin with a code label |
1936 | and end with an unconditional jump. If so, it returns that predecessor | |
1937 | block. (This is to avoid creating lots of new basic blocks that all | |
1938 | contain unconditional jumps to the same destination). */ | |
1939 | ||
1940 | static basic_block | |
a0c938f0 | 1941 | find_jump_block (basic_block jump_dest) |
1942 | { | |
1943 | basic_block source_bb = NULL; | |
4f18499c | 1944 | edge e; |
867177a5 | 1945 | rtx_insn *insn; |
cd665a06 | 1946 | edge_iterator ei; |
4f18499c | 1947 | |
cd665a06 | 1948 | FOR_EACH_EDGE (e, ei, jump_dest->preds) |
9858d888 | 1949 | if (e->flags & EDGE_CROSSING) |
4f18499c | 1950 | { |
1951 | basic_block src = e->src; | |
a0c938f0 | 1952 | |
4f18499c | 1953 | /* Check each predecessor to see if it has a label, and contains |
1954 | only one executable instruction, which is an unconditional jump. | |
0bed3869 | 1955 | If so, we can use it. */ |
a0c938f0 | 1956 | |
6d7dc5b9 | 1957 | if (LABEL_P (BB_HEAD (src))) |
a0c938f0 | 1958 | for (insn = BB_HEAD (src); |
4f18499c | 1959 | !INSN_P (insn) && insn != NEXT_INSN (BB_END (src)); |
1960 | insn = NEXT_INSN (insn)) | |
1961 | { | |
1962 | if (INSN_P (insn) | |
1963 | && insn == BB_END (src) | |
6d7dc5b9 | 1964 | && JUMP_P (insn) |
4f18499c | 1965 | && !any_condjump_p (insn)) |
1966 | { | |
1967 | source_bb = src; | |
1968 | break; | |
1969 | } | |
1970 | } | |
a0c938f0 | 1971 | |
4f18499c | 1972 | if (source_bb) |
1973 | break; | |
1974 | } | |
1975 | ||
1976 | return source_bb; | |
1977 | } | |
1978 | ||
1979 | /* Find all BB's with conditional jumps that are crossing edges; | |
1980 | insert a new bb and make the conditional jump branch to the new | |
1981 | bb instead (make the new bb same color so conditional branch won't | |
1982 | be a 'crossing' edge). Insert an unconditional jump from the | |
1983 | new bb to the original destination of the conditional jump. */ | |
1984 | ||
1985 | static void | |
1986 | fix_crossing_conditional_branches (void) | |
1987 | { | |
1988 | basic_block cur_bb; | |
1989 | basic_block new_bb; | |
4f18499c | 1990 | basic_block dest; |
4f18499c | 1991 | edge succ1; |
1992 | edge succ2; | |
1993 | edge crossing_edge; | |
1994 | edge new_edge; | |
4f18499c | 1995 | rtx set_src; |
1996 | rtx old_label = NULL_RTX; | |
f9a00e9e | 1997 | rtx_code_label *new_label; |
a0c938f0 | 1998 | |
fc00614f | 1999 | FOR_EACH_BB_FN (cur_bb, cfun) |
4f18499c | 2000 | { |
2001 | crossing_edge = NULL; | |
cd665a06 | 2002 | if (EDGE_COUNT (cur_bb->succs) > 0) |
2003 | succ1 = EDGE_SUCC (cur_bb, 0); | |
2004 | else | |
2005 | succ1 = NULL; | |
a0c938f0 | 2006 | |
cd665a06 | 2007 | if (EDGE_COUNT (cur_bb->succs) > 1) |
2008 | succ2 = EDGE_SUCC (cur_bb, 1); | |
4f18499c | 2009 | else |
cd665a06 | 2010 | succ2 = NULL; |
a0c938f0 | 2011 | |
4f18499c | 2012 | /* We already took care of fall-through edges, so only one successor |
2013 | can be a crossing edge. */ | |
a0c938f0 | 2014 | |
9858d888 | 2015 | if (succ1 && (succ1->flags & EDGE_CROSSING)) |
4f18499c | 2016 | crossing_edge = succ1; |
9858d888 | 2017 | else if (succ2 && (succ2->flags & EDGE_CROSSING)) |
a0c938f0 | 2018 | crossing_edge = succ2; |
2019 | ||
2020 | if (crossing_edge) | |
2021 | { | |
ea44a2ac | 2022 | rtx_insn *old_jump = BB_END (cur_bb); |
a0c938f0 | 2023 | |
4f18499c | 2024 | /* Check to make sure the jump instruction is a |
2025 | conditional jump. */ | |
a0c938f0 | 2026 | |
4f18499c | 2027 | set_src = NULL_RTX; |
2028 | ||
2029 | if (any_condjump_p (old_jump)) | |
2030 | { | |
2031 | if (GET_CODE (PATTERN (old_jump)) == SET) | |
2032 | set_src = SET_SRC (PATTERN (old_jump)); | |
2033 | else if (GET_CODE (PATTERN (old_jump)) == PARALLEL) | |
2034 | { | |
2035 | set_src = XVECEXP (PATTERN (old_jump), 0,0); | |
2036 | if (GET_CODE (set_src) == SET) | |
2037 | set_src = SET_SRC (set_src); | |
2038 | else | |
2039 | set_src = NULL_RTX; | |
2040 | } | |
2041 | } | |
2042 | ||
2043 | if (set_src && (GET_CODE (set_src) == IF_THEN_ELSE)) | |
2044 | { | |
ea44a2ac | 2045 | rtx_jump_insn *old_jump_insn = |
2046 | as_a <rtx_jump_insn *> (old_jump); | |
2047 | ||
4f18499c | 2048 | if (GET_CODE (XEXP (set_src, 1)) == PC) |
2049 | old_label = XEXP (set_src, 2); | |
2050 | else if (GET_CODE (XEXP (set_src, 2)) == PC) | |
2051 | old_label = XEXP (set_src, 1); | |
a0c938f0 | 2052 | |
4f18499c | 2053 | /* Check to see if new bb for jumping to that dest has |
2054 | already been created; if so, use it; if not, create | |
2055 | a new one. */ | |
2056 | ||
2057 | new_bb = find_jump_block (crossing_edge->dest); | |
a0c938f0 | 2058 | |
4f18499c | 2059 | if (new_bb) |
2060 | new_label = block_label (new_bb); | |
2061 | else | |
2062 | { | |
0e1b5033 | 2063 | basic_block last_bb; |
f9a00e9e | 2064 | rtx_code_label *old_jump_target; |
2065 | rtx_jump_insn *new_jump; | |
0e1b5033 | 2066 | |
4f18499c | 2067 | /* Create new basic block to be dest for |
2068 | conditional jump. */ | |
a0c938f0 | 2069 | |
4f18499c | 2070 | /* Put appropriate instructions in new bb. */ |
a0c938f0 | 2071 | |
4f18499c | 2072 | new_label = gen_label_rtx (); |
0e1b5033 | 2073 | emit_label (new_label); |
a0c938f0 | 2074 | |
0e1b5033 | 2075 | gcc_assert (GET_CODE (old_label) == LABEL_REF); |
ea44a2ac | 2076 | old_jump_target = old_jump_insn->jump_target (); |
f9a00e9e | 2077 | new_jump = as_a <rtx_jump_insn *> |
1d5ad681 | 2078 | (emit_jump_insn (targetm.gen_jump (old_jump_target))); |
f9a00e9e | 2079 | new_jump->set_jump_target (old_jump_target); |
0e1b5033 | 2080 | |
34154e27 | 2081 | last_bb = EXIT_BLOCK_PTR_FOR_FN (cfun)->prev_bb; |
0e1b5033 | 2082 | new_bb = create_basic_block (new_label, new_jump, last_bb); |
2083 | new_bb->aux = last_bb->aux; | |
2084 | last_bb->aux = new_bb; | |
29211303 | 2085 | |
2086 | emit_barrier_after_bb (new_bb); | |
a0c938f0 | 2087 | |
4f18499c | 2088 | /* Make sure new bb is in same partition as source |
2089 | of conditional branch. */ | |
7562ed74 | 2090 | BB_COPY_PARTITION (new_bb, cur_bb); |
4f18499c | 2091 | } |
a0c938f0 | 2092 | |
4f18499c | 2093 | /* Make old jump branch to new bb. */ |
a0c938f0 | 2094 | |
ea44a2ac | 2095 | redirect_jump (old_jump_insn, new_label, 0); |
a0c938f0 | 2096 | |
4f18499c | 2097 | /* Remove crossing_edge as predecessor of 'dest'. */ |
a0c938f0 | 2098 | |
4f18499c | 2099 | dest = crossing_edge->dest; |
a0c938f0 | 2100 | |
4f18499c | 2101 | redirect_edge_succ (crossing_edge, new_bb); |
a0c938f0 | 2102 | |
4f18499c | 2103 | /* Make a new edge from new_bb to old dest; new edge |
2104 | will be a successor for new_bb and a predecessor | |
2105 | for 'dest'. */ | |
a0c938f0 | 2106 | |
cd665a06 | 2107 | if (EDGE_COUNT (new_bb->succs) == 0) |
4f18499c | 2108 | new_edge = make_edge (new_bb, dest, 0); |
2109 | else | |
cd665a06 | 2110 | new_edge = EDGE_SUCC (new_bb, 0); |
a0c938f0 | 2111 | |
9858d888 | 2112 | crossing_edge->flags &= ~EDGE_CROSSING; |
2113 | new_edge->flags |= EDGE_CROSSING; | |
4f18499c | 2114 | } |
a0c938f0 | 2115 | } |
4f18499c | 2116 | } |
2117 | } | |
2118 | ||
2119 | /* Find any unconditional branches that cross between hot and cold | |
2120 | sections. Convert them into indirect jumps instead. */ | |
2121 | ||
2122 | static void | |
2123 | fix_crossing_unconditional_branches (void) | |
2124 | { | |
2125 | basic_block cur_bb; | |
867177a5 | 2126 | rtx_insn *last_insn; |
4f18499c | 2127 | rtx label; |
2128 | rtx label_addr; | |
867177a5 | 2129 | rtx_insn *indirect_jump_sequence; |
2130 | rtx_insn *jump_insn = NULL; | |
4f18499c | 2131 | rtx new_reg; |
867177a5 | 2132 | rtx_insn *cur_insn; |
4f18499c | 2133 | edge succ; |
065efcb1 | 2134 | |
fc00614f | 2135 | FOR_EACH_BB_FN (cur_bb, cfun) |
4f18499c | 2136 | { |
2137 | last_insn = BB_END (cur_bb); | |
1897b881 | 2138 | |
2139 | if (EDGE_COUNT (cur_bb->succs) < 1) | |
2140 | continue; | |
2141 | ||
cd665a06 | 2142 | succ = EDGE_SUCC (cur_bb, 0); |
4f18499c | 2143 | |
2144 | /* Check to see if bb ends in a crossing (unconditional) jump. At | |
a0c938f0 | 2145 | this point, no crossing jumps should be conditional. */ |
4f18499c | 2146 | |
6d7dc5b9 | 2147 | if (JUMP_P (last_insn) |
9858d888 | 2148 | && (succ->flags & EDGE_CROSSING)) |
4f18499c | 2149 | { |
64db345d | 2150 | gcc_assert (!any_condjump_p (last_insn)); |
4f18499c | 2151 | |
2152 | /* Make sure the jump is not already an indirect or table jump. */ | |
2153 | ||
64db345d | 2154 | if (!computed_jump_p (last_insn) |
b257b412 | 2155 | && !tablejump_p (last_insn, NULL, NULL)) |
4f18499c | 2156 | { |
2157 | /* We have found a "crossing" unconditional branch. Now | |
2158 | we must convert it to an indirect jump. First create | |
2159 | reference of label, as target for jump. */ | |
a0c938f0 | 2160 | |
4f18499c | 2161 | label = JUMP_LABEL (last_insn); |
692222b0 | 2162 | label_addr = gen_rtx_LABEL_REF (Pmode, label); |
4f18499c | 2163 | LABEL_NUSES (label) += 1; |
a0c938f0 | 2164 | |
4f18499c | 2165 | /* Get a register to use for the indirect jump. */ |
a0c938f0 | 2166 | |
4f18499c | 2167 | new_reg = gen_reg_rtx (Pmode); |
a0c938f0 | 2168 | |
4f18499c | 2169 | /* Generate indirect the jump sequence. */ |
a0c938f0 | 2170 | |
4f18499c | 2171 | start_sequence (); |
2172 | emit_move_insn (new_reg, label_addr); | |
2173 | emit_indirect_jump (new_reg); | |
2174 | indirect_jump_sequence = get_insns (); | |
2175 | end_sequence (); | |
a0c938f0 | 2176 | |
4f18499c | 2177 | /* Make sure every instruction in the new jump sequence has |
2178 | its basic block set to be cur_bb. */ | |
a0c938f0 | 2179 | |
4f18499c | 2180 | for (cur_insn = indirect_jump_sequence; cur_insn; |
2181 | cur_insn = NEXT_INSN (cur_insn)) | |
2182 | { | |
560414c6 | 2183 | if (!BARRIER_P (cur_insn)) |
2184 | BLOCK_FOR_INSN (cur_insn) = cur_bb; | |
6d7dc5b9 | 2185 | if (JUMP_P (cur_insn)) |
4f18499c | 2186 | jump_insn = cur_insn; |
2187 | } | |
a0c938f0 | 2188 | |
4f18499c | 2189 | /* Insert the new (indirect) jump sequence immediately before |
2190 | the unconditional jump, then delete the unconditional jump. */ | |
a0c938f0 | 2191 | |
4f18499c | 2192 | emit_insn_before (indirect_jump_sequence, last_insn); |
2193 | delete_insn (last_insn); | |
a0c938f0 | 2194 | |
4aadd22a | 2195 | JUMP_LABEL (jump_insn) = label; |
2196 | LABEL_NUSES (label)++; | |
2197 | ||
4f18499c | 2198 | /* Make BB_END for cur_bb be the jump instruction (NOT the |
2199 | barrier instruction at the end of the sequence...). */ | |
a0c938f0 | 2200 | |
26bb3cb2 | 2201 | BB_END (cur_bb) = jump_insn; |
4f18499c | 2202 | } |
2203 | } | |
2204 | } | |
2205 | } | |
2206 | ||
8f869004 | 2207 | /* Update CROSSING_JUMP_P flags on all jump insns. */ |
4f18499c | 2208 | |
2209 | static void | |
8f869004 | 2210 | update_crossing_jump_flags (void) |
4f18499c | 2211 | { |
2212 | basic_block bb; | |
2213 | edge e; | |
cd665a06 | 2214 | edge_iterator ei; |
4f18499c | 2215 | |
fc00614f | 2216 | FOR_EACH_BB_FN (bb, cfun) |
cd665a06 | 2217 | FOR_EACH_EDGE (e, ei, bb->succs) |
8f869004 | 2218 | if (e->flags & EDGE_CROSSING) |
2219 | { | |
2220 | if (JUMP_P (BB_END (bb)) | |
2221 | /* Some flags were added during fix_up_fall_thru_edges, via | |
2222 | force_nonfallthru_and_redirect. */ | |
2223 | && !CROSSING_JUMP_P (BB_END (bb))) | |
2224 | CROSSING_JUMP_P (BB_END (bb)) = 1; | |
2225 | break; | |
2226 | } | |
4f18499c | 2227 | } |
2228 | ||
90df23f8 | 2229 | /* Reorder basic blocks using the software trace cache (STC) algorithm. */ |
a6540cbf | 2230 | |
d2bb3f9d | 2231 | static void |
90df23f8 | 2232 | reorder_basic_blocks_software_trace_cache (void) |
a6540cbf | 2233 | { |
2f619490 | 2234 | if (dump_file) |
2235 | fprintf (dump_file, "\nReordering with the STC algorithm.\n\n"); | |
2236 | ||
674f7a9c | 2237 | int n_traces; |
2238 | int i; | |
2239 | struct trace *traces; | |
2240 | ||
d01481af | 2241 | /* We are estimating the length of uncond jump insn only once since the code |
2242 | for getting the insn length always returns the minimal length now. */ | |
aecda0d6 | 2243 | if (uncond_jump_length == 0) |
674f7a9c | 2244 | uncond_jump_length = get_uncond_jump_length (); |
2245 | ||
2246 | /* We need to know some information for each basic block. */ | |
fe672ac0 | 2247 | array_size = GET_ARRAY_SIZE (last_basic_block_for_fn (cfun)); |
4c36ffe6 | 2248 | bbd = XNEWVEC (bbro_basic_block_data, array_size); |
674f7a9c | 2249 | for (i = 0; i < array_size; i++) |
2250 | { | |
2251 | bbd[i].start_of_trace = -1; | |
2252 | bbd[i].end_of_trace = -1; | |
43e94e51 | 2253 | bbd[i].in_trace = -1; |
2254 | bbd[i].visited = 0; | |
674f7a9c | 2255 | bbd[i].heap = NULL; |
2256 | bbd[i].node = NULL; | |
2257 | } | |
2258 | ||
a28770e1 | 2259 | traces = XNEWVEC (struct trace, n_basic_blocks_for_fn (cfun)); |
674f7a9c | 2260 | n_traces = 0; |
2261 | find_traces (&n_traces, traces); | |
2262 | connect_traces (n_traces, traces); | |
2263 | FREE (traces); | |
2264 | FREE (bbd); | |
90df23f8 | 2265 | } |
2266 | ||
2f619490 | 2267 | /* Return true if edge E1 is more desirable as a fallthrough edge than |
2268 | edge E2 is. */ | |
2269 | ||
2270 | static bool | |
2271 | edge_order (edge e1, edge e2) | |
2272 | { | |
2273 | return EDGE_FREQUENCY (e1) > EDGE_FREQUENCY (e2); | |
2274 | } | |
2275 | ||
2276 | /* Reorder basic blocks using the "simple" algorithm. This tries to | |
2277 | maximize the dynamic number of branches that are fallthrough, without | |
2278 | copying instructions. The algorithm is greedy, looking at the most | |
2279 | frequently executed branch first. */ | |
2280 | ||
2281 | static void | |
2282 | reorder_basic_blocks_simple (void) | |
2283 | { | |
2284 | if (dump_file) | |
2285 | fprintf (dump_file, "\nReordering with the \"simple\" algorithm.\n\n"); | |
2286 | ||
2287 | edge *edges = new edge[2 * n_basic_blocks_for_fn (cfun)]; | |
2288 | ||
2289 | /* First, collect all edges that can be optimized by reordering blocks: | |
2290 | simple jumps and conditional jumps, as well as the function entry edge. */ | |
2291 | ||
2292 | int n = 0; | |
2293 | edges[n++] = EDGE_SUCC (ENTRY_BLOCK_PTR_FOR_FN (cfun), 0); | |
2294 | ||
2295 | basic_block bb; | |
2296 | FOR_EACH_BB_FN (bb, cfun) | |
2297 | { | |
2298 | rtx_insn *end = BB_END (bb); | |
2299 | ||
2300 | if (computed_jump_p (end) || tablejump_p (end, NULL, NULL)) | |
2301 | continue; | |
2302 | ||
2303 | /* We cannot optimize asm goto. */ | |
2304 | if (JUMP_P (end) && extract_asm_operands (end)) | |
2305 | continue; | |
2306 | ||
d3a06cc5 | 2307 | if (single_succ_p (bb)) |
2308 | edges[n++] = EDGE_SUCC (bb, 0); | |
2309 | else if (any_condjump_p (end)) | |
2f619490 | 2310 | { |
d66909e1 | 2311 | edge e0 = EDGE_SUCC (bb, 0); |
2312 | edge e1 = EDGE_SUCC (bb, 1); | |
2313 | /* When optimizing for size it is best to keep the original | |
2314 | fallthrough edges. */ | |
2315 | if (e1->flags & EDGE_FALLTHRU) | |
2316 | std::swap (e0, e1); | |
2317 | edges[n++] = e0; | |
2318 | edges[n++] = e1; | |
2f619490 | 2319 | } |
2f619490 | 2320 | } |
2321 | ||
d66909e1 | 2322 | /* Sort the edges, the most desirable first. When optimizing for size |
2323 | all edges are equally desirable. */ | |
2f619490 | 2324 | |
d66909e1 | 2325 | if (optimize_function_for_speed_p (cfun)) |
2326 | std::stable_sort (edges, edges + n, edge_order); | |
2f619490 | 2327 | |
2328 | /* Now decide which of those edges to make fallthrough edges. We set | |
2329 | BB_VISITED if a block already has a fallthrough successor assigned | |
2330 | to it. We make ->AUX of an endpoint point to the opposite endpoint | |
2331 | of a sequence of blocks that fall through, and ->AUX will be NULL | |
2332 | for a block that is in such a sequence but not an endpoint anymore. | |
2333 | ||
2334 | To start with, everything points to itself, nothing is assigned yet. */ | |
2335 | ||
2336 | FOR_ALL_BB_FN (bb, cfun) | |
2337 | bb->aux = bb; | |
2338 | ||
2339 | EXIT_BLOCK_PTR_FOR_FN (cfun)->aux = 0; | |
2340 | ||
2341 | /* Now for all edges, the most desirable first, see if that edge can | |
2342 | connect two sequences. If it can, update AUX and BB_VISITED; if it | |
2343 | cannot, zero out the edge in the table. */ | |
2344 | ||
2345 | for (int j = 0; j < n; j++) | |
2346 | { | |
2347 | edge e = edges[j]; | |
2348 | ||
2349 | basic_block tail_a = e->src; | |
2350 | basic_block head_b = e->dest; | |
2351 | basic_block head_a = (basic_block) tail_a->aux; | |
2352 | basic_block tail_b = (basic_block) head_b->aux; | |
2353 | ||
2354 | /* An edge cannot connect two sequences if: | |
2355 | - it crosses partitions; | |
2356 | - its src is not a current endpoint; | |
2357 | - its dest is not a current endpoint; | |
2358 | - or, it would create a loop. */ | |
2359 | ||
2360 | if (e->flags & EDGE_CROSSING | |
2361 | || tail_a->flags & BB_VISITED | |
2362 | || !tail_b | |
2363 | || (!(head_b->flags & BB_VISITED) && head_b != tail_b) | |
2364 | || tail_a == tail_b) | |
2365 | { | |
2366 | edges[j] = 0; | |
2367 | continue; | |
2368 | } | |
2369 | ||
2370 | tail_a->aux = 0; | |
2371 | head_b->aux = 0; | |
2372 | head_a->aux = tail_b; | |
2373 | tail_b->aux = head_a; | |
2374 | tail_a->flags |= BB_VISITED; | |
2375 | } | |
2376 | ||
2377 | /* Put the pieces together, in the same order that the start blocks of | |
2378 | the sequences already had. The hot/cold partitioning gives a little | |
2379 | complication: as a first pass only do this for blocks in the same | |
2380 | partition as the start block, and (if there is anything left to do) | |
2381 | in a second pass handle the other partition. */ | |
2382 | ||
2383 | basic_block last_tail = (basic_block) ENTRY_BLOCK_PTR_FOR_FN (cfun)->aux; | |
2384 | ||
2385 | int current_partition = BB_PARTITION (last_tail); | |
2386 | bool need_another_pass = true; | |
2387 | ||
2388 | for (int pass = 0; pass < 2 && need_another_pass; pass++) | |
2389 | { | |
2390 | need_another_pass = false; | |
2391 | ||
2392 | FOR_EACH_BB_FN (bb, cfun) | |
2393 | if ((bb->flags & BB_VISITED && bb->aux) || bb->aux == bb) | |
2394 | { | |
2395 | if (BB_PARTITION (bb) != current_partition) | |
2396 | { | |
2397 | need_another_pass = true; | |
2398 | continue; | |
2399 | } | |
2400 | ||
2401 | last_tail->aux = bb; | |
2402 | last_tail = (basic_block) bb->aux; | |
2403 | } | |
2404 | ||
2405 | current_partition ^= BB_HOT_PARTITION | BB_COLD_PARTITION; | |
2406 | } | |
2407 | ||
2408 | last_tail->aux = 0; | |
2409 | ||
2410 | /* Finally, link all the chosen fallthrough edges. */ | |
2411 | ||
2412 | for (int j = 0; j < n; j++) | |
2413 | if (edges[j]) | |
2414 | edges[j]->src->aux = edges[j]->dest; | |
2415 | ||
2416 | delete[] edges; | |
2417 | ||
2418 | /* If the entry edge no longer falls through we have to make a new | |
2419 | block so it can do so again. */ | |
2420 | ||
2421 | edge e = EDGE_SUCC (ENTRY_BLOCK_PTR_FOR_FN (cfun), 0); | |
2422 | if (e->dest != ENTRY_BLOCK_PTR_FOR_FN (cfun)->aux) | |
2423 | { | |
2424 | force_nonfallthru (e); | |
2425 | e->src->aux = ENTRY_BLOCK_PTR_FOR_FN (cfun)->aux; | |
2426 | BB_COPY_PARTITION (e->src, e->dest); | |
2427 | } | |
2428 | } | |
2429 | ||
90df23f8 | 2430 | /* Reorder basic blocks. The main entry point to this file. */ |
2431 | ||
2432 | static void | |
2433 | reorder_basic_blocks (void) | |
2434 | { | |
2435 | gcc_assert (current_ir_type () == IR_RTL_CFGLAYOUT); | |
2436 | ||
2437 | if (n_basic_blocks_for_fn (cfun) <= NUM_FIXED_BLOCKS + 1) | |
2438 | return; | |
2439 | ||
2440 | set_edge_can_fallthru_flag (); | |
2441 | mark_dfs_back_edges (); | |
2442 | ||
e57ef194 | 2443 | switch (flag_reorder_blocks_algorithm) |
2444 | { | |
2445 | case REORDER_BLOCKS_ALGORITHM_SIMPLE: | |
2446 | reorder_basic_blocks_simple (); | |
2447 | break; | |
2448 | ||
2449 | case REORDER_BLOCKS_ALGORITHM_STC: | |
2450 | reorder_basic_blocks_software_trace_cache (); | |
2451 | break; | |
2452 | ||
2453 | default: | |
2454 | gcc_unreachable (); | |
2455 | } | |
65f34de5 | 2456 | |
207c7ab2 | 2457 | relink_block_chain (/*stay_in_cfglayout_mode=*/true); |
2458 | ||
450d042a | 2459 | if (dump_file) |
4a020a8c | 2460 | { |
2461 | if (dump_flags & TDF_DETAILS) | |
2462 | dump_reg_info (dump_file); | |
2463 | dump_flow_info (dump_file, dump_flags); | |
2464 | } | |
65f34de5 | 2465 | |
812ca88e | 2466 | /* Signal that rtl_verify_flow_info_1 can now verify that there |
2467 | is at most one switch between hot/cold sections. */ | |
2468 | crtl->bb_reorder_complete = true; | |
a6540cbf | 2469 | } |
b70a5a99 | 2470 | |
1897b881 | 2471 | /* Determine which partition the first basic block in the function |
2472 | belongs to, then find the first basic block in the current function | |
2473 | that belongs to a different section, and insert a | |
2474 | NOTE_INSN_SWITCH_TEXT_SECTIONS note immediately before it in the | |
2475 | instruction stream. When writing out the assembly code, | |
2476 | encountering this note will make the compiler switch between the | |
2477 | hot and cold text sections. */ | |
2478 | ||
aa78dca5 | 2479 | void |
1897b881 | 2480 | insert_section_boundary_note (void) |
2481 | { | |
2482 | basic_block bb; | |
aa78dca5 | 2483 | bool switched_sections = false; |
2484 | int current_partition = 0; | |
a0c938f0 | 2485 | |
aa78dca5 | 2486 | if (!crtl->has_bb_partition) |
9f8fb9f2 | 2487 | return; |
2488 | ||
fc00614f | 2489 | FOR_EACH_BB_FN (bb, cfun) |
1897b881 | 2490 | { |
aa78dca5 | 2491 | if (!current_partition) |
2492 | current_partition = BB_PARTITION (bb); | |
2493 | if (BB_PARTITION (bb) != current_partition) | |
1897b881 | 2494 | { |
aa78dca5 | 2495 | gcc_assert (!switched_sections); |
2496 | switched_sections = true; | |
2497 | emit_note_before (NOTE_INSN_SWITCH_TEXT_SECTIONS, BB_HEAD (bb)); | |
2498 | current_partition = BB_PARTITION (bb); | |
1897b881 | 2499 | } |
2500 | } | |
2501 | } | |
2502 | ||
cbe8bda8 | 2503 | namespace { |
2504 | ||
2505 | const pass_data pass_data_reorder_blocks = | |
160f10e2 | 2506 | { |
cbe8bda8 | 2507 | RTL_PASS, /* type */ |
2508 | "bbro", /* name */ | |
2509 | OPTGROUP_NONE, /* optinfo_flags */ | |
cbe8bda8 | 2510 | TV_REORDER_BLOCKS, /* tv_id */ |
2511 | 0, /* properties_required */ | |
2512 | 0, /* properties_provided */ | |
2513 | 0, /* properties_destroyed */ | |
2514 | 0, /* todo_flags_start */ | |
8b88439e | 2515 | 0, /* todo_flags_finish */ |
160f10e2 | 2516 | }; |
2517 | ||
cbe8bda8 | 2518 | class pass_reorder_blocks : public rtl_opt_pass |
2519 | { | |
2520 | public: | |
9af5ce0c | 2521 | pass_reorder_blocks (gcc::context *ctxt) |
2522 | : rtl_opt_pass (pass_data_reorder_blocks, ctxt) | |
cbe8bda8 | 2523 | {} |
2524 | ||
2525 | /* opt_pass methods: */ | |
31315c24 | 2526 | virtual bool gate (function *) |
2527 | { | |
2528 | if (targetm.cannot_modify_jumps_p ()) | |
2529 | return false; | |
2530 | return (optimize > 0 | |
2531 | && (flag_reorder_blocks || flag_reorder_blocks_and_partition)); | |
2532 | } | |
2533 | ||
65b0537f | 2534 | virtual unsigned int execute (function *); |
cbe8bda8 | 2535 | |
2536 | }; // class pass_reorder_blocks | |
2537 | ||
65b0537f | 2538 | unsigned int |
2539 | pass_reorder_blocks::execute (function *fun) | |
2540 | { | |
2541 | basic_block bb; | |
2542 | ||
2543 | /* Last attempt to optimize CFG, as scheduling, peepholing and insn | |
2544 | splitting possibly introduced more crossjumping opportunities. */ | |
2545 | cfg_layout_initialize (CLEANUP_EXPENSIVE); | |
2546 | ||
2547 | reorder_basic_blocks (); | |
2548 | cleanup_cfg (CLEANUP_EXPENSIVE); | |
2549 | ||
2550 | FOR_EACH_BB_FN (bb, fun) | |
2551 | if (bb->next_bb != EXIT_BLOCK_PTR_FOR_FN (fun)) | |
2552 | bb->aux = bb->next_bb; | |
2553 | cfg_layout_finalize (); | |
2554 | ||
2555 | return 0; | |
2556 | } | |
2557 | ||
cbe8bda8 | 2558 | } // anon namespace |
2559 | ||
2560 | rtl_opt_pass * | |
2561 | make_pass_reorder_blocks (gcc::context *ctxt) | |
2562 | { | |
2563 | return new pass_reorder_blocks (ctxt); | |
2564 | } | |
2565 | ||
b70a5a99 | 2566 | /* Duplicate the blocks containing computed gotos. This basically unfactors |
2567 | computed gotos that were factored early on in the compilation process to | |
2568 | speed up edge based data flow. We used to not unfactoring them again, | |
2569 | which can seriously pessimize code with many computed jumps in the source | |
2570 | code, such as interpreters. See e.g. PR15242. */ | |
2571 | ||
65b0537f | 2572 | namespace { |
77fce4cd | 2573 | |
65b0537f | 2574 | const pass_data pass_data_duplicate_computed_gotos = |
2575 | { | |
2576 | RTL_PASS, /* type */ | |
2577 | "compgotos", /* name */ | |
2578 | OPTGROUP_NONE, /* optinfo_flags */ | |
65b0537f | 2579 | TV_REORDER_BLOCKS, /* tv_id */ |
2580 | 0, /* properties_required */ | |
2581 | 0, /* properties_provided */ | |
2582 | 0, /* properties_destroyed */ | |
2583 | 0, /* todo_flags_start */ | |
8b88439e | 2584 | 0, /* todo_flags_finish */ |
65b0537f | 2585 | }; |
2586 | ||
2587 | class pass_duplicate_computed_gotos : public rtl_opt_pass | |
2588 | { | |
2589 | public: | |
2590 | pass_duplicate_computed_gotos (gcc::context *ctxt) | |
2591 | : rtl_opt_pass (pass_data_duplicate_computed_gotos, ctxt) | |
2592 | {} | |
2593 | ||
2594 | /* opt_pass methods: */ | |
2595 | virtual bool gate (function *); | |
2596 | virtual unsigned int execute (function *); | |
2597 | ||
2598 | }; // class pass_duplicate_computed_gotos | |
2599 | ||
2600 | bool | |
2601 | pass_duplicate_computed_gotos::gate (function *fun) | |
2602 | { | |
2603 | if (targetm.cannot_modify_jumps_p ()) | |
2604 | return false; | |
2605 | return (optimize > 0 | |
2606 | && flag_expensive_optimizations | |
2607 | && ! optimize_function_for_size_p (fun)); | |
2608 | } | |
2609 | ||
2610 | unsigned int | |
2611 | pass_duplicate_computed_gotos::execute (function *fun) | |
b70a5a99 | 2612 | { |
2613 | basic_block bb, new_bb; | |
2614 | bitmap candidates; | |
2615 | int max_size; | |
4a3e6cf5 | 2616 | bool changed = false; |
b70a5a99 | 2617 | |
65b0537f | 2618 | if (n_basic_blocks_for_fn (fun) <= NUM_FIXED_BLOCKS + 1) |
2a1990e9 | 2619 | return 0; |
b70a5a99 | 2620 | |
43e94e51 | 2621 | clear_bb_flags (); |
b70a5a99 | 2622 | cfg_layout_initialize (0); |
2623 | ||
2624 | /* We are estimating the length of uncond jump insn only once | |
2625 | since the code for getting the insn length always returns | |
2626 | the minimal length now. */ | |
2627 | if (uncond_jump_length == 0) | |
2628 | uncond_jump_length = get_uncond_jump_length (); | |
2629 | ||
b2f6568f | 2630 | max_size |
2631 | = uncond_jump_length * PARAM_VALUE (PARAM_MAX_GOTO_DUPLICATION_INSNS); | |
27335ffd | 2632 | candidates = BITMAP_ALLOC (NULL); |
b70a5a99 | 2633 | |
f7334ae5 | 2634 | /* Look for blocks that end in a computed jump, and see if such blocks |
2635 | are suitable for unfactoring. If a block is a candidate for unfactoring, | |
2636 | mark it in the candidates. */ | |
65b0537f | 2637 | FOR_EACH_BB_FN (bb, fun) |
b70a5a99 | 2638 | { |
867177a5 | 2639 | rtx_insn *insn; |
f7334ae5 | 2640 | edge e; |
2641 | edge_iterator ei; | |
2642 | int size, all_flags; | |
2643 | ||
2644 | /* Build the reorder chain for the original order of blocks. */ | |
65b0537f | 2645 | if (bb->next_bb != EXIT_BLOCK_PTR_FOR_FN (fun)) |
bc5f266a | 2646 | bb->aux = bb->next_bb; |
b70a5a99 | 2647 | |
f7334ae5 | 2648 | /* Obviously the block has to end in a computed jump. */ |
2649 | if (!computed_jump_p (BB_END (bb))) | |
2650 | continue; | |
b70a5a99 | 2651 | |
f7334ae5 | 2652 | /* Only consider blocks that can be duplicated. */ |
8f869004 | 2653 | if (CROSSING_JUMP_P (BB_END (bb)) |
f7334ae5 | 2654 | || !can_duplicate_block_p (bb)) |
2655 | continue; | |
b70a5a99 | 2656 | |
f7334ae5 | 2657 | /* Make sure that the block is small enough. */ |
2658 | size = 0; | |
2659 | FOR_BB_INSNS (bb, insn) | |
2660 | if (INSN_P (insn)) | |
2661 | { | |
16afa8ae | 2662 | size += get_attr_min_length (insn); |
f7334ae5 | 2663 | if (size > max_size) |
2664 | break; | |
2665 | } | |
2666 | if (size > max_size) | |
2667 | continue; | |
2668 | ||
2669 | /* Final check: there must not be any incoming abnormal edges. */ | |
2670 | all_flags = 0; | |
2671 | FOR_EACH_EDGE (e, ei, bb->preds) | |
2672 | all_flags |= e->flags; | |
2673 | if (all_flags & EDGE_COMPLEX) | |
2674 | continue; | |
2675 | ||
2676 | bitmap_set_bit (candidates, bb->index); | |
b70a5a99 | 2677 | } |
2678 | ||
2679 | /* Nothing to do if there is no computed jump here. */ | |
2680 | if (bitmap_empty_p (candidates)) | |
2681 | goto done; | |
2682 | ||
2683 | /* Duplicate computed gotos. */ | |
65b0537f | 2684 | FOR_EACH_BB_FN (bb, fun) |
b70a5a99 | 2685 | { |
43e94e51 | 2686 | if (bb->flags & BB_VISITED) |
b70a5a99 | 2687 | continue; |
2688 | ||
43e94e51 | 2689 | bb->flags |= BB_VISITED; |
b70a5a99 | 2690 | |
2691 | /* BB must have one outgoing edge. That edge must not lead to | |
a0c938f0 | 2692 | the exit block or the next block. |
b70a5a99 | 2693 | The destination must have more than one predecessor. */ |
ea091dfd | 2694 | if (!single_succ_p (bb) |
65b0537f | 2695 | || single_succ (bb) == EXIT_BLOCK_PTR_FOR_FN (fun) |
ea091dfd | 2696 | || single_succ (bb) == bb->next_bb |
2697 | || single_pred_p (single_succ (bb))) | |
b70a5a99 | 2698 | continue; |
2699 | ||
2700 | /* The successor block has to be a duplication candidate. */ | |
ea091dfd | 2701 | if (!bitmap_bit_p (candidates, single_succ (bb)->index)) |
b70a5a99 | 2702 | continue; |
2703 | ||
aa78dca5 | 2704 | /* Don't duplicate a partition crossing edge, which requires difficult |
2705 | fixup. */ | |
8f869004 | 2706 | if (JUMP_P (BB_END (bb)) && CROSSING_JUMP_P (BB_END (bb))) |
aa78dca5 | 2707 | continue; |
2708 | ||
c4d867e0 | 2709 | new_bb = duplicate_block (single_succ (bb), single_succ_edge (bb), bb); |
bc5f266a | 2710 | new_bb->aux = bb->aux; |
2711 | bb->aux = new_bb; | |
43e94e51 | 2712 | new_bb->flags |= BB_VISITED; |
4a3e6cf5 | 2713 | changed = true; |
b70a5a99 | 2714 | } |
2715 | ||
9f4ec746 | 2716 | done: |
4a3e6cf5 | 2717 | if (changed) |
9f4ec746 | 2718 | { |
2719 | /* Duplicating blocks above will redirect edges and may cause hot | |
2720 | blocks previously reached by both hot and cold blocks to become | |
2721 | dominated only by cold blocks. */ | |
2722 | fixup_partitions (); | |
2723 | ||
2724 | /* Merge the duplicated blocks into predecessors, when possible. */ | |
2725 | cfg_layout_finalize (); | |
2726 | cleanup_cfg (0); | |
2727 | } | |
2728 | else | |
2729 | cfg_layout_finalize (); | |
b70a5a99 | 2730 | |
27335ffd | 2731 | BITMAP_FREE (candidates); |
2a1990e9 | 2732 | return 0; |
b70a5a99 | 2733 | } |
4f18499c | 2734 | |
cbe8bda8 | 2735 | } // anon namespace |
2736 | ||
2737 | rtl_opt_pass * | |
2738 | make_pass_duplicate_computed_gotos (gcc::context *ctxt) | |
2739 | { | |
2740 | return new pass_duplicate_computed_gotos (ctxt); | |
2741 | } | |
2742 | ||
4f18499c | 2743 | /* This function is the main 'entrance' for the optimization that |
2744 | partitions hot and cold basic blocks into separate sections of the | |
2745 | .o file (to improve performance and cache locality). Ideally it | |
2746 | would be called after all optimizations that rearrange the CFG have | |
2747 | been called. However part of this optimization may introduce new | |
2748 | register usage, so it must be called before register allocation has | |
2749 | occurred. This means that this optimization is actually called | |
1118aef7 | 2750 | well before the optimization that reorders basic blocks (see |
2751 | function above). | |
4f18499c | 2752 | |
2753 | This optimization checks the feedback information to determine | |
1897b881 | 2754 | which basic blocks are hot/cold, updates flags on the basic blocks |
2755 | to indicate which section they belong in. This information is | |
2756 | later used for writing out sections in the .o file. Because hot | |
2757 | and cold sections can be arbitrarily large (within the bounds of | |
2758 | memory), far beyond the size of a single function, it is necessary | |
2759 | to fix up all edges that cross section boundaries, to make sure the | |
2760 | instructions used can actually span the required distance. The | |
2761 | fixes are described below. | |
1118aef7 | 2762 | |
2763 | Fall-through edges must be changed into jumps; it is not safe or | |
2764 | legal to fall through across a section boundary. Whenever a | |
2765 | fall-through edge crossing a section boundary is encountered, a new | |
2766 | basic block is inserted (in the same section as the fall-through | |
2767 | source), and the fall through edge is redirected to the new basic | |
2768 | block. The new basic block contains an unconditional jump to the | |
2769 | original fall-through target. (If the unconditional jump is | |
2770 | insufficient to cross section boundaries, that is dealt with a | |
2771 | little later, see below). | |
2772 | ||
2773 | In order to deal with architectures that have short conditional | |
2774 | branches (which cannot span all of memory) we take any conditional | |
2775 | jump that attempts to cross a section boundary and add a level of | |
2776 | indirection: it becomes a conditional jump to a new basic block, in | |
2777 | the same section. The new basic block contains an unconditional | |
2778 | jump to the original target, in the other section. | |
2779 | ||
2780 | For those architectures whose unconditional branch is also | |
2781 | incapable of reaching all of memory, those unconditional jumps are | |
2782 | converted into indirect jumps, through a register. | |
2783 | ||
2784 | IMPORTANT NOTE: This optimization causes some messy interactions | |
2785 | with the cfg cleanup optimizations; those optimizations want to | |
2786 | merge blocks wherever possible, and to collapse indirect jump | |
2787 | sequences (change "A jumps to B jumps to C" directly into "A jumps | |
2788 | to C"). Those optimizations can undo the jump fixes that | |
2789 | partitioning is required to make (see above), in order to ensure | |
2790 | that jumps attempting to cross section boundaries are really able | |
2791 | to cover whatever distance the jump requires (on many architectures | |
2792 | conditional or unconditional jumps are not able to reach all of | |
2793 | memory). Therefore tests have to be inserted into each such | |
2794 | optimization to make sure that it does not undo stuff necessary to | |
2795 | cross partition boundaries. This would be much less of a problem | |
2796 | if we could perform this optimization later in the compilation, but | |
2797 | unfortunately the fact that we may need to create indirect jumps | |
2798 | (through registers) requires that this optimization be performed | |
2a8e5eeb | 2799 | before register allocation. |
4f18499c | 2800 | |
2a8e5eeb | 2801 | Hot and cold basic blocks are partitioned and put in separate |
2802 | sections of the .o file, to reduce paging and improve cache | |
2803 | performance (hopefully). This can result in bits of code from the | |
2804 | same function being widely separated in the .o file. However this | |
2805 | is not obvious to the current bb structure. Therefore we must take | |
2806 | care to ensure that: 1). There are no fall_thru edges that cross | |
2807 | between sections; 2). For those architectures which have "short" | |
2808 | conditional branches, all conditional branches that attempt to | |
2809 | cross between sections are converted to unconditional branches; | |
2810 | and, 3). For those architectures which have "short" unconditional | |
2811 | branches, all unconditional branches that attempt to cross between | |
2812 | sections are converted to indirect jumps. | |
2813 | ||
2814 | The code for fixing up fall_thru edges that cross between hot and | |
2815 | cold basic blocks does so by creating new basic blocks containing | |
2816 | unconditional branches to the appropriate label in the "other" | |
2817 | section. The new basic block is then put in the same (hot or cold) | |
2818 | section as the original conditional branch, and the fall_thru edge | |
2819 | is modified to fall into the new basic block instead. By adding | |
2820 | this level of indirection we end up with only unconditional branches | |
2821 | crossing between hot and cold sections. | |
2822 | ||
2823 | Conditional branches are dealt with by adding a level of indirection. | |
2824 | A new basic block is added in the same (hot/cold) section as the | |
2825 | conditional branch, and the conditional branch is retargeted to the | |
2826 | new basic block. The new basic block contains an unconditional branch | |
2827 | to the original target of the conditional branch (in the other section). | |
2828 | ||
2829 | Unconditional branches are dealt with by converting them into | |
2830 | indirect jumps. */ | |
2831 | ||
65b0537f | 2832 | namespace { |
2833 | ||
2834 | const pass_data pass_data_partition_blocks = | |
2835 | { | |
2836 | RTL_PASS, /* type */ | |
2837 | "bbpart", /* name */ | |
2838 | OPTGROUP_NONE, /* optinfo_flags */ | |
65b0537f | 2839 | TV_REORDER_BLOCKS, /* tv_id */ |
2840 | PROP_cfglayout, /* properties_required */ | |
2841 | 0, /* properties_provided */ | |
2842 | 0, /* properties_destroyed */ | |
2843 | 0, /* todo_flags_start */ | |
2844 | 0, /* todo_flags_finish */ | |
2845 | }; | |
2846 | ||
2847 | class pass_partition_blocks : public rtl_opt_pass | |
2848 | { | |
2849 | public: | |
2850 | pass_partition_blocks (gcc::context *ctxt) | |
2851 | : rtl_opt_pass (pass_data_partition_blocks, ctxt) | |
2852 | {} | |
2853 | ||
2854 | /* opt_pass methods: */ | |
2855 | virtual bool gate (function *); | |
2856 | virtual unsigned int execute (function *); | |
2857 | ||
2858 | }; // class pass_partition_blocks | |
2859 | ||
2860 | bool | |
2861 | pass_partition_blocks::gate (function *fun) | |
2862 | { | |
2863 | /* The optimization to partition hot/cold basic blocks into separate | |
2864 | sections of the .o file does not work well with linkonce or with | |
2865 | user defined section attributes. Don't call it if either case | |
2866 | arises. */ | |
2867 | return (flag_reorder_blocks_and_partition | |
2868 | && optimize | |
2869 | /* See gate_handle_reorder_blocks. We should not partition if | |
2870 | we are going to omit the reordering. */ | |
2871 | && optimize_function_for_speed_p (fun) | |
b395f451 | 2872 | && !DECL_COMDAT_GROUP (current_function_decl) |
65b0537f | 2873 | && !user_defined_section_attribute); |
2874 | } | |
2875 | ||
2876 | unsigned | |
2877 | pass_partition_blocks::execute (function *fun) | |
4f18499c | 2878 | { |
f1f41a6c | 2879 | vec<edge> crossing_edges; |
a0c938f0 | 2880 | |
65b0537f | 2881 | if (n_basic_blocks_for_fn (fun) <= NUM_FIXED_BLOCKS + 1) |
2a8e5eeb | 2882 | return 0; |
2883 | ||
f59cbcbf | 2884 | df_set_flags (DF_DEFER_INSN_RESCAN); |
2885 | ||
2a8e5eeb | 2886 | crossing_edges = find_rarely_executed_basic_blocks_and_crossing_edges (); |
f1f41a6c | 2887 | if (!crossing_edges.exists ()) |
2a8e5eeb | 2888 | return 0; |
2889 | ||
812ca88e | 2890 | crtl->has_bb_partition = true; |
2891 | ||
2a8e5eeb | 2892 | /* Make sure the source of any crossing edge ends in a jump and the |
2893 | destination of any crossing edge has a label. */ | |
2894 | add_labels_and_missing_jumps (crossing_edges); | |
2895 | ||
2896 | /* Convert all crossing fall_thru edges to non-crossing fall | |
2897 | thrus to unconditional jumps (that jump to the original fall | |
9d75589a | 2898 | through dest). */ |
2a8e5eeb | 2899 | fix_up_fall_thru_edges (); |
2900 | ||
2901 | /* If the architecture does not have conditional branches that can | |
2902 | span all of memory, convert crossing conditional branches into | |
2903 | crossing unconditional branches. */ | |
2904 | if (!HAS_LONG_COND_BRANCH) | |
2905 | fix_crossing_conditional_branches (); | |
a0c938f0 | 2906 | |
2a8e5eeb | 2907 | /* If the architecture does not have unconditional branches that |
2908 | can span all of memory, convert crossing unconditional branches | |
2909 | into indirect jumps. Since adding an indirect jump also adds | |
2910 | a new register usage, update the register usage information as | |
2911 | well. */ | |
2912 | if (!HAS_LONG_UNCOND_BRANCH) | |
2913 | fix_crossing_unconditional_branches (); | |
4f18499c | 2914 | |
8f869004 | 2915 | update_crossing_jump_flags (); |
4f18499c | 2916 | |
b9aec3f5 | 2917 | /* Clear bb->aux fields that the above routines were using. */ |
2918 | clear_aux_for_blocks (); | |
2919 | ||
f1f41a6c | 2920 | crossing_edges.release (); |
a0c938f0 | 2921 | |
f59cbcbf | 2922 | /* ??? FIXME: DF generates the bb info for a block immediately. |
2923 | And by immediately, I mean *during* creation of the block. | |
2924 | ||
2925 | #0 df_bb_refs_collect | |
2926 | #1 in df_bb_refs_record | |
2927 | #2 in create_basic_block_structure | |
2928 | ||
2929 | Which means that the bb_has_eh_pred test in df_bb_refs_collect | |
2930 | will *always* fail, because no edges can have been added to the | |
2931 | block yet. Which of course means we don't add the right | |
2932 | artificial refs, which means we fail df_verify (much) later. | |
2933 | ||
2934 | Cleanest solution would seem to make DF_DEFER_INSN_RESCAN imply | |
2935 | that we also shouldn't grab data from the new blocks those new | |
2936 | insns are in either. In this way one can create the block, link | |
2937 | it up properly, and have everything Just Work later, when deferred | |
2938 | insns are processed. | |
2939 | ||
2940 | In the meantime, we have no other option but to throw away all | |
2941 | of the DF data and recompute it all. */ | |
65b0537f | 2942 | if (fun->eh->lp_array) |
f59cbcbf | 2943 | { |
2944 | df_finish_pass (true); | |
2945 | df_scan_alloc (NULL); | |
2946 | df_scan_blocks (); | |
2947 | /* Not all post-landing pads use all of the EH_RETURN_DATA_REGNO | |
2948 | data. We blindly generated all of them when creating the new | |
2949 | landing pad. Delete those assignments we don't use. */ | |
2950 | df_set_flags (DF_LR_RUN_DCE); | |
2951 | df_analyze (); | |
2952 | } | |
2953 | ||
8b88439e | 2954 | return 0; |
4f18499c | 2955 | } |
77fce4cd | 2956 | |
cbe8bda8 | 2957 | } // anon namespace |
2958 | ||
2959 | rtl_opt_pass * | |
2960 | make_pass_partition_blocks (gcc::context *ctxt) | |
2961 | { | |
2962 | return new pass_partition_blocks (ctxt); | |
2963 | } |