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750628d8 | 1 | /* Generic SSA value propagation engine. |
0bca51f0 | 2 | Copyright (C) 2004, 2005 Free Software Foundation, Inc. |
750628d8 DN |
3 | Contributed by Diego Novillo <dnovillo@redhat.com> |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify it | |
8 | under the terms of the GNU General Public License as published by the | |
9 | Free Software Foundation; either version 2, or (at your option) any | |
10 | later version. | |
11 | ||
12 | GCC is distributed in the hope that it will be useful, but WITHOUT | |
13 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with GCC; see the file COPYING. If not, write to the Free | |
366ccddb KC |
19 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA |
20 | 02110-1301, USA. */ | |
750628d8 DN |
21 | |
22 | #include "config.h" | |
23 | #include "system.h" | |
24 | #include "coretypes.h" | |
25 | #include "tm.h" | |
26 | #include "tree.h" | |
27 | #include "flags.h" | |
28 | #include "rtl.h" | |
29 | #include "tm_p.h" | |
30 | #include "ggc.h" | |
31 | #include "basic-block.h" | |
32 | #include "output.h" | |
750628d8 DN |
33 | #include "expr.h" |
34 | #include "function.h" | |
35 | #include "diagnostic.h" | |
36 | #include "timevar.h" | |
37 | #include "tree-dump.h" | |
38 | #include "tree-flow.h" | |
39 | #include "tree-pass.h" | |
40 | #include "tree-ssa-propagate.h" | |
41 | #include "langhooks.h" | |
78492bf5 SB |
42 | #include "varray.h" |
43 | #include "vec.h" | |
750628d8 DN |
44 | |
45 | /* This file implements a generic value propagation engine based on | |
46 | the same propagation used by the SSA-CCP algorithm [1]. | |
47 | ||
48 | Propagation is performed by simulating the execution of every | |
49 | statement that produces the value being propagated. Simulation | |
50 | proceeds as follows: | |
51 | ||
52 | 1- Initially, all edges of the CFG are marked not executable and | |
766ff1b1 | 53 | the CFG worklist is seeded with all the statements in the entry |
750628d8 DN |
54 | basic block (block 0). |
55 | ||
56 | 2- Every statement S is simulated with a call to the call-back | |
57 | function SSA_PROP_VISIT_STMT. This evaluation may produce 3 | |
58 | results: | |
59 | ||
60 | SSA_PROP_NOT_INTERESTING: Statement S produces nothing of | |
61 | interest and does not affect any of the work lists. | |
62 | ||
63 | SSA_PROP_VARYING: The value produced by S cannot be determined | |
64 | at compile time. Further simulation of S is not required. | |
65 | If S is a conditional jump, all the outgoing edges for the | |
66 | block are considered executable and added to the work | |
67 | list. | |
68 | ||
69 | SSA_PROP_INTERESTING: S produces a value that can be computed | |
70 | at compile time. Its result can be propagated into the | |
2a7e31df | 71 | statements that feed from S. Furthermore, if S is a |
750628d8 DN |
72 | conditional jump, only the edge known to be taken is added |
73 | to the work list. Edges that are known not to execute are | |
74 | never simulated. | |
75 | ||
76 | 3- PHI nodes are simulated with a call to SSA_PROP_VISIT_PHI. The | |
77 | return value from SSA_PROP_VISIT_PHI has the same semantics as | |
766ff1b1 | 78 | described in #2. |
750628d8 DN |
79 | |
80 | 4- Three work lists are kept. Statements are only added to these | |
81 | lists if they produce one of SSA_PROP_INTERESTING or | |
82 | SSA_PROP_VARYING. | |
83 | ||
84 | CFG_BLOCKS contains the list of blocks to be simulated. | |
85 | Blocks are added to this list if their incoming edges are | |
86 | found executable. | |
87 | ||
88 | VARYING_SSA_EDGES contains the list of statements that feed | |
89 | from statements that produce an SSA_PROP_VARYING result. | |
90 | These are simulated first to speed up processing. | |
91 | ||
92 | INTERESTING_SSA_EDGES contains the list of statements that | |
93 | feed from statements that produce an SSA_PROP_INTERESTING | |
94 | result. | |
95 | ||
96 | 5- Simulation terminates when all three work lists are drained. | |
97 | ||
98 | Before calling ssa_propagate, it is important to clear | |
99 | DONT_SIMULATE_AGAIN for all the statements in the program that | |
100 | should be simulated. This initialization allows an implementation | |
101 | to specify which statements should never be simulated. | |
102 | ||
103 | It is also important to compute def-use information before calling | |
104 | ssa_propagate. | |
105 | ||
106 | References: | |
107 | ||
108 | [1] Constant propagation with conditional branches, | |
109 | Wegman and Zadeck, ACM TOPLAS 13(2):181-210. | |
110 | ||
111 | [2] Building an Optimizing Compiler, | |
112 | Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9. | |
113 | ||
114 | [3] Advanced Compiler Design and Implementation, | |
115 | Steven Muchnick, Morgan Kaufmann, 1997, Section 12.6 */ | |
116 | ||
117 | /* Function pointers used to parameterize the propagation engine. */ | |
118 | static ssa_prop_visit_stmt_fn ssa_prop_visit_stmt; | |
119 | static ssa_prop_visit_phi_fn ssa_prop_visit_phi; | |
120 | ||
121 | /* Use the TREE_DEPRECATED bitflag to mark statements that have been | |
122 | added to one of the SSA edges worklists. This flag is used to | |
123 | avoid visiting statements unnecessarily when draining an SSA edge | |
124 | worklist. If while simulating a basic block, we find a statement with | |
125 | STMT_IN_SSA_EDGE_WORKLIST set, we clear it to prevent SSA edge | |
126 | processing from visiting it again. */ | |
127 | #define STMT_IN_SSA_EDGE_WORKLIST(T) TREE_DEPRECATED (T) | |
128 | ||
129 | /* A bitmap to keep track of executable blocks in the CFG. */ | |
130 | static sbitmap executable_blocks; | |
131 | ||
132 | /* Array of control flow edges on the worklist. */ | |
133 | static GTY(()) varray_type cfg_blocks = NULL; | |
134 | ||
135 | static unsigned int cfg_blocks_num = 0; | |
136 | static int cfg_blocks_tail; | |
137 | static int cfg_blocks_head; | |
138 | ||
139 | static sbitmap bb_in_list; | |
140 | ||
141 | /* Worklist of SSA edges which will need reexamination as their | |
142 | definition has changed. SSA edges are def-use edges in the SSA | |
143 | web. For each D-U edge, we store the target statement or PHI node | |
144 | U. */ | |
d4e6fecb | 145 | static GTY(()) VEC(tree,gc) *interesting_ssa_edges; |
750628d8 DN |
146 | |
147 | /* Identical to INTERESTING_SSA_EDGES. For performance reasons, the | |
148 | list of SSA edges is split into two. One contains all SSA edges | |
149 | who need to be reexamined because their lattice value changed to | |
150 | varying (this worklist), and the other contains all other SSA edges | |
151 | to be reexamined (INTERESTING_SSA_EDGES). | |
152 | ||
153 | Since most values in the program are VARYING, the ideal situation | |
154 | is to move them to that lattice value as quickly as possible. | |
155 | Thus, it doesn't make sense to process any other type of lattice | |
156 | value until all VARYING values are propagated fully, which is one | |
157 | thing using the VARYING worklist achieves. In addition, if we | |
158 | don't use a separate worklist for VARYING edges, we end up with | |
159 | situations where lattice values move from | |
160 | UNDEFINED->INTERESTING->VARYING instead of UNDEFINED->VARYING. */ | |
d4e6fecb | 161 | static GTY(()) VEC(tree,gc) *varying_ssa_edges; |
750628d8 DN |
162 | |
163 | ||
164 | /* Return true if the block worklist empty. */ | |
165 | ||
166 | static inline bool | |
167 | cfg_blocks_empty_p (void) | |
168 | { | |
169 | return (cfg_blocks_num == 0); | |
170 | } | |
171 | ||
172 | ||
78492bf5 | 173 | /* Add a basic block to the worklist. The block must not be already |
39850c0b | 174 | in the worklist, and it must not be the ENTRY or EXIT block. */ |
750628d8 DN |
175 | |
176 | static void | |
177 | cfg_blocks_add (basic_block bb) | |
178 | { | |
39850c0b | 179 | gcc_assert (bb != ENTRY_BLOCK_PTR && bb != EXIT_BLOCK_PTR); |
78492bf5 | 180 | gcc_assert (!TEST_BIT (bb_in_list, bb->index)); |
750628d8 DN |
181 | |
182 | if (cfg_blocks_empty_p ()) | |
183 | { | |
184 | cfg_blocks_tail = cfg_blocks_head = 0; | |
185 | cfg_blocks_num = 1; | |
186 | } | |
187 | else | |
188 | { | |
189 | cfg_blocks_num++; | |
190 | if (cfg_blocks_num > VARRAY_SIZE (cfg_blocks)) | |
191 | { | |
192 | /* We have to grow the array now. Adjust to queue to occupy the | |
193 | full space of the original array. */ | |
194 | cfg_blocks_tail = VARRAY_SIZE (cfg_blocks); | |
195 | cfg_blocks_head = 0; | |
196 | VARRAY_GROW (cfg_blocks, 2 * VARRAY_SIZE (cfg_blocks)); | |
197 | } | |
198 | else | |
199 | cfg_blocks_tail = (cfg_blocks_tail + 1) % VARRAY_SIZE (cfg_blocks); | |
200 | } | |
201 | ||
202 | VARRAY_BB (cfg_blocks, cfg_blocks_tail) = bb; | |
203 | SET_BIT (bb_in_list, bb->index); | |
204 | } | |
205 | ||
206 | ||
207 | /* Remove a block from the worklist. */ | |
208 | ||
209 | static basic_block | |
210 | cfg_blocks_get (void) | |
211 | { | |
212 | basic_block bb; | |
213 | ||
214 | bb = VARRAY_BB (cfg_blocks, cfg_blocks_head); | |
215 | ||
1e128c5f GB |
216 | gcc_assert (!cfg_blocks_empty_p ()); |
217 | gcc_assert (bb); | |
750628d8 DN |
218 | |
219 | cfg_blocks_head = (cfg_blocks_head + 1) % VARRAY_SIZE (cfg_blocks); | |
220 | --cfg_blocks_num; | |
221 | RESET_BIT (bb_in_list, bb->index); | |
222 | ||
223 | return bb; | |
224 | } | |
225 | ||
226 | ||
227 | /* We have just defined a new value for VAR. If IS_VARYING is true, | |
228 | add all immediate uses of VAR to VARYING_SSA_EDGES, otherwise add | |
229 | them to INTERESTING_SSA_EDGES. */ | |
230 | ||
231 | static void | |
232 | add_ssa_edge (tree var, bool is_varying) | |
233 | { | |
f430bae8 AM |
234 | imm_use_iterator iter; |
235 | use_operand_p use_p; | |
750628d8 | 236 | |
f430bae8 | 237 | FOR_EACH_IMM_USE_FAST (use_p, iter, var) |
750628d8 | 238 | { |
f430bae8 | 239 | tree use_stmt = USE_STMT (use_p); |
750628d8 DN |
240 | |
241 | if (!DONT_SIMULATE_AGAIN (use_stmt) | |
242 | && !STMT_IN_SSA_EDGE_WORKLIST (use_stmt)) | |
243 | { | |
244 | STMT_IN_SSA_EDGE_WORKLIST (use_stmt) = 1; | |
245 | if (is_varying) | |
d4e6fecb | 246 | VEC_safe_push (tree, gc, varying_ssa_edges, use_stmt); |
750628d8 | 247 | else |
d4e6fecb | 248 | VEC_safe_push (tree, gc, interesting_ssa_edges, use_stmt); |
750628d8 DN |
249 | } |
250 | } | |
251 | } | |
252 | ||
253 | ||
254 | /* Add edge E to the control flow worklist. */ | |
255 | ||
256 | static void | |
257 | add_control_edge (edge e) | |
258 | { | |
259 | basic_block bb = e->dest; | |
260 | if (bb == EXIT_BLOCK_PTR) | |
261 | return; | |
262 | ||
263 | /* If the edge had already been executed, skip it. */ | |
264 | if (e->flags & EDGE_EXECUTABLE) | |
265 | return; | |
266 | ||
267 | e->flags |= EDGE_EXECUTABLE; | |
268 | ||
269 | /* If the block is already in the list, we're done. */ | |
270 | if (TEST_BIT (bb_in_list, bb->index)) | |
271 | return; | |
272 | ||
273 | cfg_blocks_add (bb); | |
274 | ||
275 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
276 | fprintf (dump_file, "Adding Destination of edge (%d -> %d) to worklist\n\n", | |
277 | e->src->index, e->dest->index); | |
278 | } | |
279 | ||
280 | ||
281 | /* Simulate the execution of STMT and update the work lists accordingly. */ | |
282 | ||
283 | static void | |
284 | simulate_stmt (tree stmt) | |
285 | { | |
286 | enum ssa_prop_result val = SSA_PROP_NOT_INTERESTING; | |
287 | edge taken_edge = NULL; | |
288 | tree output_name = NULL_TREE; | |
289 | ||
290 | /* Don't bother visiting statements that are already | |
291 | considered varying by the propagator. */ | |
292 | if (DONT_SIMULATE_AGAIN (stmt)) | |
293 | return; | |
294 | ||
295 | if (TREE_CODE (stmt) == PHI_NODE) | |
296 | { | |
297 | val = ssa_prop_visit_phi (stmt); | |
298 | output_name = PHI_RESULT (stmt); | |
299 | } | |
300 | else | |
301 | val = ssa_prop_visit_stmt (stmt, &taken_edge, &output_name); | |
302 | ||
303 | if (val == SSA_PROP_VARYING) | |
304 | { | |
305 | DONT_SIMULATE_AGAIN (stmt) = 1; | |
306 | ||
307 | /* If the statement produced a new varying value, add the SSA | |
308 | edges coming out of OUTPUT_NAME. */ | |
309 | if (output_name) | |
310 | add_ssa_edge (output_name, true); | |
311 | ||
312 | /* If STMT transfers control out of its basic block, add | |
313 | all outgoing edges to the work list. */ | |
314 | if (stmt_ends_bb_p (stmt)) | |
315 | { | |
316 | edge e; | |
628f6a4e | 317 | edge_iterator ei; |
750628d8 | 318 | basic_block bb = bb_for_stmt (stmt); |
628f6a4e | 319 | FOR_EACH_EDGE (e, ei, bb->succs) |
750628d8 DN |
320 | add_control_edge (e); |
321 | } | |
322 | } | |
323 | else if (val == SSA_PROP_INTERESTING) | |
324 | { | |
325 | /* If the statement produced new value, add the SSA edges coming | |
326 | out of OUTPUT_NAME. */ | |
327 | if (output_name) | |
328 | add_ssa_edge (output_name, false); | |
329 | ||
330 | /* If we know which edge is going to be taken out of this block, | |
331 | add it to the CFG work list. */ | |
332 | if (taken_edge) | |
333 | add_control_edge (taken_edge); | |
334 | } | |
335 | } | |
336 | ||
337 | /* Process an SSA edge worklist. WORKLIST is the SSA edge worklist to | |
338 | drain. This pops statements off the given WORKLIST and processes | |
78492bf5 SB |
339 | them until there are no more statements on WORKLIST. |
340 | We take a pointer to WORKLIST because it may be reallocated when an | |
341 | SSA edge is added to it in simulate_stmt. */ | |
750628d8 DN |
342 | |
343 | static void | |
d4e6fecb | 344 | process_ssa_edge_worklist (VEC(tree,gc) **worklist) |
750628d8 DN |
345 | { |
346 | /* Drain the entire worklist. */ | |
78492bf5 | 347 | while (VEC_length (tree, *worklist) > 0) |
750628d8 DN |
348 | { |
349 | basic_block bb; | |
350 | ||
351 | /* Pull the statement to simulate off the worklist. */ | |
78492bf5 | 352 | tree stmt = VEC_pop (tree, *worklist); |
750628d8 DN |
353 | |
354 | /* If this statement was already visited by simulate_block, then | |
355 | we don't need to visit it again here. */ | |
356 | if (!STMT_IN_SSA_EDGE_WORKLIST (stmt)) | |
357 | continue; | |
358 | ||
359 | /* STMT is no longer in a worklist. */ | |
360 | STMT_IN_SSA_EDGE_WORKLIST (stmt) = 0; | |
361 | ||
362 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
363 | { | |
364 | fprintf (dump_file, "\nSimulating statement (from ssa_edges): "); | |
365 | print_generic_stmt (dump_file, stmt, dump_flags); | |
366 | } | |
367 | ||
368 | bb = bb_for_stmt (stmt); | |
369 | ||
370 | /* PHI nodes are always visited, regardless of whether or not | |
371 | the destination block is executable. Otherwise, visit the | |
372 | statement only if its block is marked executable. */ | |
373 | if (TREE_CODE (stmt) == PHI_NODE | |
374 | || TEST_BIT (executable_blocks, bb->index)) | |
375 | simulate_stmt (stmt); | |
376 | } | |
377 | } | |
378 | ||
379 | ||
380 | /* Simulate the execution of BLOCK. Evaluate the statement associated | |
381 | with each variable reference inside the block. */ | |
382 | ||
383 | static void | |
384 | simulate_block (basic_block block) | |
385 | { | |
386 | tree phi; | |
387 | ||
388 | /* There is nothing to do for the exit block. */ | |
389 | if (block == EXIT_BLOCK_PTR) | |
390 | return; | |
391 | ||
392 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
393 | fprintf (dump_file, "\nSimulating block %d\n", block->index); | |
394 | ||
395 | /* Always simulate PHI nodes, even if we have simulated this block | |
396 | before. */ | |
397 | for (phi = phi_nodes (block); phi; phi = PHI_CHAIN (phi)) | |
398 | simulate_stmt (phi); | |
399 | ||
400 | /* If this is the first time we've simulated this block, then we | |
401 | must simulate each of its statements. */ | |
402 | if (!TEST_BIT (executable_blocks, block->index)) | |
403 | { | |
404 | block_stmt_iterator j; | |
405 | unsigned int normal_edge_count; | |
406 | edge e, normal_edge; | |
628f6a4e | 407 | edge_iterator ei; |
750628d8 DN |
408 | |
409 | /* Note that we have simulated this block. */ | |
410 | SET_BIT (executable_blocks, block->index); | |
411 | ||
412 | for (j = bsi_start (block); !bsi_end_p (j); bsi_next (&j)) | |
413 | { | |
414 | tree stmt = bsi_stmt (j); | |
415 | ||
416 | /* If this statement is already in the worklist then | |
417 | "cancel" it. The reevaluation implied by the worklist | |
418 | entry will produce the same value we generate here and | |
419 | thus reevaluating it again from the worklist is | |
420 | pointless. */ | |
421 | if (STMT_IN_SSA_EDGE_WORKLIST (stmt)) | |
422 | STMT_IN_SSA_EDGE_WORKLIST (stmt) = 0; | |
423 | ||
424 | simulate_stmt (stmt); | |
425 | } | |
426 | ||
427 | /* We can not predict when abnormal edges will be executed, so | |
428 | once a block is considered executable, we consider any | |
429 | outgoing abnormal edges as executable. | |
430 | ||
431 | At the same time, if this block has only one successor that is | |
432 | reached by non-abnormal edges, then add that successor to the | |
433 | worklist. */ | |
434 | normal_edge_count = 0; | |
435 | normal_edge = NULL; | |
628f6a4e | 436 | FOR_EACH_EDGE (e, ei, block->succs) |
750628d8 DN |
437 | { |
438 | if (e->flags & EDGE_ABNORMAL) | |
439 | add_control_edge (e); | |
440 | else | |
441 | { | |
442 | normal_edge_count++; | |
443 | normal_edge = e; | |
444 | } | |
445 | } | |
446 | ||
447 | if (normal_edge_count == 1) | |
448 | add_control_edge (normal_edge); | |
449 | } | |
450 | } | |
451 | ||
452 | ||
453 | /* Initialize local data structures and work lists. */ | |
454 | ||
455 | static void | |
456 | ssa_prop_init (void) | |
457 | { | |
458 | edge e; | |
628f6a4e | 459 | edge_iterator ei; |
750628d8 | 460 | basic_block bb; |
0bca51f0 | 461 | size_t i; |
750628d8 DN |
462 | |
463 | /* Worklists of SSA edges. */ | |
d4e6fecb NS |
464 | interesting_ssa_edges = VEC_alloc (tree, gc, 20); |
465 | varying_ssa_edges = VEC_alloc (tree, gc, 20); | |
750628d8 DN |
466 | |
467 | executable_blocks = sbitmap_alloc (last_basic_block); | |
468 | sbitmap_zero (executable_blocks); | |
469 | ||
470 | bb_in_list = sbitmap_alloc (last_basic_block); | |
471 | sbitmap_zero (bb_in_list); | |
472 | ||
473 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
474 | dump_immediate_uses (dump_file); | |
475 | ||
476 | VARRAY_BB_INIT (cfg_blocks, 20, "cfg_blocks"); | |
477 | ||
0bca51f0 DN |
478 | /* Initialize the values for every SSA_NAME. */ |
479 | for (i = 1; i < num_ssa_names; i++) | |
480 | if (ssa_name (i)) | |
481 | SSA_NAME_VALUE (ssa_name (i)) = NULL_TREE; | |
482 | ||
483 | /* Initially assume that every edge in the CFG is not executable. | |
0777d852 DN |
484 | (including the edges coming out of ENTRY_BLOCK_PTR). */ |
485 | FOR_ALL_BB (bb) | |
750628d8 DN |
486 | { |
487 | block_stmt_iterator si; | |
488 | ||
489 | for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si)) | |
490 | STMT_IN_SSA_EDGE_WORKLIST (bsi_stmt (si)) = 0; | |
491 | ||
628f6a4e | 492 | FOR_EACH_EDGE (e, ei, bb->succs) |
750628d8 DN |
493 | e->flags &= ~EDGE_EXECUTABLE; |
494 | } | |
495 | ||
496 | /* Seed the algorithm by adding the successors of the entry block to the | |
497 | edge worklist. */ | |
628f6a4e | 498 | FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs) |
39850c0b | 499 | add_control_edge (e); |
750628d8 DN |
500 | } |
501 | ||
502 | ||
503 | /* Free allocated storage. */ | |
504 | ||
505 | static void | |
506 | ssa_prop_fini (void) | |
507 | { | |
d4e6fecb NS |
508 | VEC_free (tree, gc, interesting_ssa_edges); |
509 | VEC_free (tree, gc, varying_ssa_edges); | |
750628d8 DN |
510 | cfg_blocks = NULL; |
511 | sbitmap_free (bb_in_list); | |
512 | sbitmap_free (executable_blocks); | |
750628d8 DN |
513 | } |
514 | ||
515 | ||
516 | /* Get the main expression from statement STMT. */ | |
517 | ||
518 | tree | |
519 | get_rhs (tree stmt) | |
520 | { | |
521 | enum tree_code code = TREE_CODE (stmt); | |
522 | ||
523 | switch (code) | |
524 | { | |
525 | case RETURN_EXPR: | |
526 | stmt = TREE_OPERAND (stmt, 0); | |
527 | if (!stmt || TREE_CODE (stmt) != MODIFY_EXPR) | |
528 | return stmt; | |
529 | /* FALLTHRU */ | |
530 | ||
531 | case MODIFY_EXPR: | |
532 | stmt = TREE_OPERAND (stmt, 1); | |
533 | if (TREE_CODE (stmt) == WITH_SIZE_EXPR) | |
534 | return TREE_OPERAND (stmt, 0); | |
535 | else | |
536 | return stmt; | |
537 | ||
538 | case COND_EXPR: | |
539 | return COND_EXPR_COND (stmt); | |
540 | case SWITCH_EXPR: | |
541 | return SWITCH_COND (stmt); | |
542 | case GOTO_EXPR: | |
543 | return GOTO_DESTINATION (stmt); | |
544 | case LABEL_EXPR: | |
545 | return LABEL_EXPR_LABEL (stmt); | |
546 | ||
547 | default: | |
548 | return stmt; | |
549 | } | |
550 | } | |
551 | ||
552 | ||
553 | /* Set the main expression of *STMT_P to EXPR. If EXPR is not a valid | |
554 | GIMPLE expression no changes are done and the function returns | |
555 | false. */ | |
556 | ||
557 | bool | |
558 | set_rhs (tree *stmt_p, tree expr) | |
559 | { | |
560 | tree stmt = *stmt_p, op; | |
561 | enum tree_code code = TREE_CODE (expr); | |
562 | stmt_ann_t ann; | |
563 | tree var; | |
564 | ssa_op_iter iter; | |
565 | ||
566 | /* Verify the constant folded result is valid gimple. */ | |
6615c446 | 567 | if (TREE_CODE_CLASS (code) == tcc_binary) |
750628d8 DN |
568 | { |
569 | if (!is_gimple_val (TREE_OPERAND (expr, 0)) | |
570 | || !is_gimple_val (TREE_OPERAND (expr, 1))) | |
571 | return false; | |
572 | } | |
887da9bd | 573 | else if (TREE_CODE_CLASS (code) == tcc_unary) |
750628d8 DN |
574 | { |
575 | if (!is_gimple_val (TREE_OPERAND (expr, 0))) | |
576 | return false; | |
577 | } | |
c5542940 RG |
578 | else if (code == ADDR_EXPR) |
579 | { | |
580 | if (TREE_CODE (TREE_OPERAND (expr, 0)) == ARRAY_REF | |
581 | && !is_gimple_val (TREE_OPERAND (TREE_OPERAND (expr, 0), 1))) | |
582 | return false; | |
583 | } | |
31d66fa9 JJ |
584 | else if (code == COMPOUND_EXPR) |
585 | return false; | |
750628d8 DN |
586 | |
587 | switch (TREE_CODE (stmt)) | |
588 | { | |
589 | case RETURN_EXPR: | |
590 | op = TREE_OPERAND (stmt, 0); | |
591 | if (TREE_CODE (op) != MODIFY_EXPR) | |
592 | { | |
593 | TREE_OPERAND (stmt, 0) = expr; | |
594 | break; | |
595 | } | |
596 | stmt = op; | |
597 | /* FALLTHRU */ | |
598 | ||
599 | case MODIFY_EXPR: | |
600 | op = TREE_OPERAND (stmt, 1); | |
601 | if (TREE_CODE (op) == WITH_SIZE_EXPR) | |
602 | stmt = op; | |
603 | TREE_OPERAND (stmt, 1) = expr; | |
604 | break; | |
605 | ||
606 | case COND_EXPR: | |
43e364dd AP |
607 | if (!is_gimple_condexpr (expr)) |
608 | return false; | |
750628d8 DN |
609 | COND_EXPR_COND (stmt) = expr; |
610 | break; | |
611 | case SWITCH_EXPR: | |
612 | SWITCH_COND (stmt) = expr; | |
613 | break; | |
614 | case GOTO_EXPR: | |
615 | GOTO_DESTINATION (stmt) = expr; | |
616 | break; | |
617 | case LABEL_EXPR: | |
618 | LABEL_EXPR_LABEL (stmt) = expr; | |
619 | break; | |
620 | ||
621 | default: | |
622 | /* Replace the whole statement with EXPR. If EXPR has no side | |
623 | effects, then replace *STMT_P with an empty statement. */ | |
624 | ann = stmt_ann (stmt); | |
625 | *stmt_p = TREE_SIDE_EFFECTS (expr) ? expr : build_empty_stmt (); | |
626 | (*stmt_p)->common.ann = (tree_ann_t) ann; | |
627 | ||
628 | if (TREE_SIDE_EFFECTS (expr)) | |
629 | { | |
630 | /* Fix all the SSA_NAMEs created by *STMT_P to point to its new | |
631 | replacement. */ | |
632 | FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_ALL_DEFS) | |
633 | { | |
634 | if (TREE_CODE (var) == SSA_NAME) | |
635 | SSA_NAME_DEF_STMT (var) = *stmt_p; | |
636 | } | |
637 | } | |
638 | break; | |
639 | } | |
640 | ||
641 | return true; | |
642 | } | |
643 | ||
644 | ||
645 | /* Entry point to the propagation engine. | |
646 | ||
647 | VISIT_STMT is called for every statement visited. | |
648 | VISIT_PHI is called for every PHI node visited. */ | |
649 | ||
650 | void | |
651 | ssa_propagate (ssa_prop_visit_stmt_fn visit_stmt, | |
652 | ssa_prop_visit_phi_fn visit_phi) | |
653 | { | |
654 | ssa_prop_visit_stmt = visit_stmt; | |
655 | ssa_prop_visit_phi = visit_phi; | |
656 | ||
657 | ssa_prop_init (); | |
658 | ||
659 | /* Iterate until the worklists are empty. */ | |
660 | while (!cfg_blocks_empty_p () | |
78492bf5 SB |
661 | || VEC_length (tree, interesting_ssa_edges) > 0 |
662 | || VEC_length (tree, varying_ssa_edges) > 0) | |
750628d8 DN |
663 | { |
664 | if (!cfg_blocks_empty_p ()) | |
665 | { | |
666 | /* Pull the next block to simulate off the worklist. */ | |
667 | basic_block dest_block = cfg_blocks_get (); | |
668 | simulate_block (dest_block); | |
669 | } | |
670 | ||
671 | /* In order to move things to varying as quickly as | |
672 | possible,process the VARYING_SSA_EDGES worklist first. */ | |
673 | process_ssa_edge_worklist (&varying_ssa_edges); | |
674 | ||
675 | /* Now process the INTERESTING_SSA_EDGES worklist. */ | |
676 | process_ssa_edge_worklist (&interesting_ssa_edges); | |
677 | } | |
678 | ||
679 | ssa_prop_fini (); | |
680 | } | |
681 | ||
0bca51f0 DN |
682 | |
683 | /* Return the first V_MAY_DEF or V_MUST_DEF operand for STMT. */ | |
684 | ||
685 | tree | |
686 | first_vdef (tree stmt) | |
687 | { | |
f47c96aa AM |
688 | ssa_op_iter iter; |
689 | tree op; | |
690 | ||
691 | /* Simply return the first operand we arrive at. */ | |
692 | FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_VIRTUAL_DEFS) | |
693 | return (op); | |
694 | ||
695 | gcc_unreachable (); | |
0bca51f0 DN |
696 | } |
697 | ||
698 | ||
699 | /* Return true if STMT is of the form 'LHS = mem_ref', where 'mem_ref' | |
700 | is a non-volatile pointer dereference, a structure reference or a | |
701 | reference to a single _DECL. Ignore volatile memory references | |
702 | because they are not interesting for the optimizers. */ | |
703 | ||
704 | bool | |
705 | stmt_makes_single_load (tree stmt) | |
706 | { | |
707 | tree rhs; | |
708 | ||
709 | if (TREE_CODE (stmt) != MODIFY_EXPR) | |
710 | return false; | |
711 | ||
f47c96aa | 712 | if (ZERO_SSA_OPERANDS (stmt, SSA_OP_VMAYDEF|SSA_OP_VUSE)) |
0bca51f0 DN |
713 | return false; |
714 | ||
715 | rhs = TREE_OPERAND (stmt, 1); | |
716 | STRIP_NOPS (rhs); | |
717 | ||
718 | return (!TREE_THIS_VOLATILE (rhs) | |
719 | && (DECL_P (rhs) | |
7da4bf7d | 720 | || REFERENCE_CLASS_P (rhs))); |
0bca51f0 DN |
721 | } |
722 | ||
723 | ||
724 | /* Return true if STMT is of the form 'mem_ref = RHS', where 'mem_ref' | |
725 | is a non-volatile pointer dereference, a structure reference or a | |
726 | reference to a single _DECL. Ignore volatile memory references | |
727 | because they are not interesting for the optimizers. */ | |
728 | ||
729 | bool | |
730 | stmt_makes_single_store (tree stmt) | |
731 | { | |
732 | tree lhs; | |
733 | ||
734 | if (TREE_CODE (stmt) != MODIFY_EXPR) | |
735 | return false; | |
736 | ||
f47c96aa | 737 | if (ZERO_SSA_OPERANDS (stmt, SSA_OP_VMAYDEF|SSA_OP_VMUSTDEF)) |
0bca51f0 DN |
738 | return false; |
739 | ||
740 | lhs = TREE_OPERAND (stmt, 0); | |
741 | STRIP_NOPS (lhs); | |
742 | ||
743 | return (!TREE_THIS_VOLATILE (lhs) | |
744 | && (DECL_P (lhs) | |
7da4bf7d | 745 | || REFERENCE_CLASS_P (lhs))); |
0bca51f0 DN |
746 | } |
747 | ||
748 | ||
749 | /* If STMT makes a single memory load and all the virtual use operands | |
750 | have the same value in array VALUES, return it. Otherwise, return | |
751 | NULL. */ | |
752 | ||
753 | prop_value_t * | |
754 | get_value_loaded_by (tree stmt, prop_value_t *values) | |
755 | { | |
756 | ssa_op_iter i; | |
757 | tree vuse; | |
758 | prop_value_t *prev_val = NULL; | |
759 | prop_value_t *val = NULL; | |
760 | ||
761 | FOR_EACH_SSA_TREE_OPERAND (vuse, stmt, i, SSA_OP_VIRTUAL_USES) | |
762 | { | |
763 | val = &values[SSA_NAME_VERSION (vuse)]; | |
764 | if (prev_val && prev_val->value != val->value) | |
765 | return NULL; | |
766 | prev_val = val; | |
767 | } | |
768 | ||
769 | return val; | |
770 | } | |
771 | ||
772 | ||
773 | /* Propagation statistics. */ | |
774 | struct prop_stats_d | |
775 | { | |
776 | long num_const_prop; | |
777 | long num_copy_prop; | |
227858d1 | 778 | long num_pred_folded; |
0bca51f0 DN |
779 | }; |
780 | ||
781 | static struct prop_stats_d prop_stats; | |
782 | ||
783 | /* Replace USE references in statement STMT with the values stored in | |
784 | PROP_VALUE. Return true if at least one reference was replaced. If | |
785 | REPLACED_ADDRESSES_P is given, it will be set to true if an address | |
786 | constant was replaced. */ | |
787 | ||
788 | bool | |
789 | replace_uses_in (tree stmt, bool *replaced_addresses_p, | |
790 | prop_value_t *prop_value) | |
791 | { | |
792 | bool replaced = false; | |
793 | use_operand_p use; | |
794 | ssa_op_iter iter; | |
795 | ||
796 | FOR_EACH_SSA_USE_OPERAND (use, stmt, iter, SSA_OP_USE) | |
797 | { | |
798 | tree tuse = USE_FROM_PTR (use); | |
799 | tree val = prop_value[SSA_NAME_VERSION (tuse)].value; | |
800 | ||
801 | if (val == tuse || val == NULL_TREE) | |
802 | continue; | |
803 | ||
804 | if (TREE_CODE (stmt) == ASM_EXPR | |
805 | && !may_propagate_copy_into_asm (tuse)) | |
806 | continue; | |
807 | ||
808 | if (!may_propagate_copy (tuse, val)) | |
809 | continue; | |
810 | ||
811 | if (TREE_CODE (val) != SSA_NAME) | |
812 | prop_stats.num_const_prop++; | |
813 | else | |
814 | prop_stats.num_copy_prop++; | |
815 | ||
816 | propagate_value (use, val); | |
817 | ||
818 | replaced = true; | |
819 | if (POINTER_TYPE_P (TREE_TYPE (tuse)) && replaced_addresses_p) | |
820 | *replaced_addresses_p = true; | |
821 | } | |
822 | ||
823 | return replaced; | |
824 | } | |
825 | ||
826 | ||
827 | /* Replace the VUSE references in statement STMT with the values | |
828 | stored in PROP_VALUE. Return true if a reference was replaced. If | |
829 | REPLACED_ADDRESSES_P is given, it will be set to true if an address | |
830 | constant was replaced. | |
831 | ||
832 | Replacing VUSE operands is slightly more complex than replacing | |
833 | regular USEs. We are only interested in two types of replacements | |
834 | here: | |
835 | ||
836 | 1- If the value to be replaced is a constant or an SSA name for a | |
837 | GIMPLE register, then we are making a copy/constant propagation | |
838 | from a memory store. For instance, | |
839 | ||
840 | # a_3 = V_MAY_DEF <a_2> | |
841 | a.b = x_1; | |
842 | ... | |
843 | # VUSE <a_3> | |
844 | y_4 = a.b; | |
845 | ||
846 | This replacement is only possible iff STMT is an assignment | |
847 | whose RHS is identical to the LHS of the statement that created | |
848 | the VUSE(s) that we are replacing. Otherwise, we may do the | |
849 | wrong replacement: | |
850 | ||
851 | # a_3 = V_MAY_DEF <a_2> | |
852 | # b_5 = V_MAY_DEF <b_4> | |
853 | *p = 10; | |
854 | ... | |
855 | # VUSE <b_5> | |
856 | x_8 = b; | |
857 | ||
858 | Even though 'b_5' acquires the value '10' during propagation, | |
859 | there is no way for the propagator to tell whether the | |
860 | replacement is correct in every reached use, because values are | |
861 | computed at definition sites. Therefore, when doing final | |
862 | substitution of propagated values, we have to check each use | |
863 | site. Since the RHS of STMT ('b') is different from the LHS of | |
864 | the originating statement ('*p'), we cannot replace 'b' with | |
865 | '10'. | |
866 | ||
867 | Similarly, when merging values from PHI node arguments, | |
868 | propagators need to take care not to merge the same values | |
869 | stored in different locations: | |
870 | ||
871 | if (...) | |
872 | # a_3 = V_MAY_DEF <a_2> | |
873 | a.b = 3; | |
874 | else | |
875 | # a_4 = V_MAY_DEF <a_2> | |
876 | a.c = 3; | |
877 | # a_5 = PHI <a_3, a_4> | |
878 | ||
879 | It would be wrong to propagate '3' into 'a_5' because that | |
880 | operation merges two stores to different memory locations. | |
881 | ||
882 | ||
883 | 2- If the value to be replaced is an SSA name for a virtual | |
884 | register, then we simply replace each VUSE operand with its | |
885 | value from PROP_VALUE. This is the same replacement done by | |
886 | replace_uses_in. */ | |
887 | ||
888 | static bool | |
889 | replace_vuses_in (tree stmt, bool *replaced_addresses_p, | |
890 | prop_value_t *prop_value) | |
891 | { | |
892 | bool replaced = false; | |
893 | ssa_op_iter iter; | |
894 | use_operand_p vuse; | |
895 | ||
896 | if (stmt_makes_single_load (stmt)) | |
897 | { | |
898 | /* If STMT is an assignment whose RHS is a single memory load, | |
899 | see if we are trying to propagate a constant or a GIMPLE | |
900 | register (case #1 above). */ | |
901 | prop_value_t *val = get_value_loaded_by (stmt, prop_value); | |
902 | tree rhs = TREE_OPERAND (stmt, 1); | |
903 | ||
904 | if (val | |
905 | && val->value | |
906 | && (is_gimple_reg (val->value) | |
907 | || is_gimple_min_invariant (val->value)) | |
908 | && simple_cst_equal (rhs, val->mem_ref) == 1) | |
909 | ||
910 | { | |
911 | /* If we are replacing a constant address, inform our | |
912 | caller. */ | |
913 | if (TREE_CODE (val->value) != SSA_NAME | |
914 | && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (stmt, 1))) | |
915 | && replaced_addresses_p) | |
916 | *replaced_addresses_p = true; | |
917 | ||
918 | /* We can only perform the substitution if the load is done | |
919 | from the same memory location as the original store. | |
920 | Since we already know that there are no intervening | |
921 | stores between DEF_STMT and STMT, we only need to check | |
922 | that the RHS of STMT is the same as the memory reference | |
923 | propagated together with the value. */ | |
924 | TREE_OPERAND (stmt, 1) = val->value; | |
925 | ||
926 | if (TREE_CODE (val->value) != SSA_NAME) | |
927 | prop_stats.num_const_prop++; | |
928 | else | |
929 | prop_stats.num_copy_prop++; | |
930 | ||
931 | /* Since we have replaced the whole RHS of STMT, there | |
932 | is no point in checking the other VUSEs, as they will | |
933 | all have the same value. */ | |
934 | return true; | |
935 | } | |
936 | } | |
937 | ||
938 | /* Otherwise, the values for every VUSE operand must be other | |
939 | SSA_NAMEs that can be propagated into STMT. */ | |
940 | FOR_EACH_SSA_USE_OPERAND (vuse, stmt, iter, SSA_OP_VIRTUAL_USES) | |
941 | { | |
942 | tree var = USE_FROM_PTR (vuse); | |
943 | tree val = prop_value[SSA_NAME_VERSION (var)].value; | |
944 | ||
945 | if (val == NULL_TREE || var == val) | |
946 | continue; | |
947 | ||
948 | /* Constants and copies propagated between real and virtual | |
949 | operands are only possible in the cases handled above. They | |
950 | should be ignored in any other context. */ | |
951 | if (is_gimple_min_invariant (val) || is_gimple_reg (val)) | |
952 | continue; | |
953 | ||
954 | propagate_value (vuse, val); | |
955 | prop_stats.num_copy_prop++; | |
956 | replaced = true; | |
957 | } | |
958 | ||
959 | return replaced; | |
960 | } | |
961 | ||
962 | ||
963 | /* Replace propagated values into all the arguments for PHI using the | |
964 | values from PROP_VALUE. */ | |
965 | ||
966 | static void | |
967 | replace_phi_args_in (tree phi, prop_value_t *prop_value) | |
968 | { | |
969 | int i; | |
227858d1 DN |
970 | bool replaced = false; |
971 | tree prev_phi = NULL; | |
972 | ||
973 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
974 | prev_phi = unshare_expr (phi); | |
0bca51f0 DN |
975 | |
976 | for (i = 0; i < PHI_NUM_ARGS (phi); i++) | |
977 | { | |
978 | tree arg = PHI_ARG_DEF (phi, i); | |
979 | ||
980 | if (TREE_CODE (arg) == SSA_NAME) | |
981 | { | |
982 | tree val = prop_value[SSA_NAME_VERSION (arg)].value; | |
983 | ||
984 | if (val && val != arg && may_propagate_copy (arg, val)) | |
985 | { | |
986 | if (TREE_CODE (val) != SSA_NAME) | |
987 | prop_stats.num_const_prop++; | |
988 | else | |
989 | prop_stats.num_copy_prop++; | |
990 | ||
991 | propagate_value (PHI_ARG_DEF_PTR (phi, i), val); | |
227858d1 | 992 | replaced = true; |
0bca51f0 DN |
993 | |
994 | /* If we propagated a copy and this argument flows | |
995 | through an abnormal edge, update the replacement | |
996 | accordingly. */ | |
997 | if (TREE_CODE (val) == SSA_NAME | |
998 | && PHI_ARG_EDGE (phi, i)->flags & EDGE_ABNORMAL) | |
999 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1; | |
1000 | } | |
1001 | } | |
1002 | } | |
227858d1 DN |
1003 | |
1004 | if (replaced && dump_file && (dump_flags & TDF_DETAILS)) | |
1005 | { | |
1006 | fprintf (dump_file, "Folded PHI node: "); | |
1007 | print_generic_stmt (dump_file, prev_phi, TDF_SLIM); | |
1008 | fprintf (dump_file, " into: "); | |
1009 | print_generic_stmt (dump_file, phi, TDF_SLIM); | |
1010 | fprintf (dump_file, "\n"); | |
1011 | } | |
1012 | } | |
1013 | ||
1014 | ||
1015 | /* If STMT has a predicate whose value can be computed using the value | |
1016 | range information computed by VRP, compute its value and return true. | |
1017 | Otherwise, return false. */ | |
1018 | ||
1019 | static bool | |
1020 | fold_predicate_in (tree stmt) | |
1021 | { | |
1022 | tree *pred_p = NULL; | |
52b27f98 | 1023 | bool modify_expr_p = false; |
227858d1 DN |
1024 | tree val; |
1025 | ||
1026 | if (TREE_CODE (stmt) == MODIFY_EXPR | |
1027 | && COMPARISON_CLASS_P (TREE_OPERAND (stmt, 1))) | |
52b27f98 AP |
1028 | { |
1029 | modify_expr_p = true; | |
1030 | pred_p = &TREE_OPERAND (stmt, 1); | |
1031 | } | |
227858d1 DN |
1032 | else if (TREE_CODE (stmt) == COND_EXPR) |
1033 | pred_p = &COND_EXPR_COND (stmt); | |
1034 | else | |
1035 | return false; | |
1036 | ||
1037 | val = vrp_evaluate_conditional (*pred_p, true); | |
1038 | if (val) | |
1039 | { | |
52b27f98 AP |
1040 | if (modify_expr_p) |
1041 | val = fold_convert (TREE_TYPE (*pred_p), val); | |
1042 | ||
227858d1 DN |
1043 | if (dump_file) |
1044 | { | |
1045 | fprintf (dump_file, "Folding predicate "); | |
1046 | print_generic_expr (dump_file, *pred_p, 0); | |
1047 | fprintf (dump_file, " to "); | |
1048 | print_generic_expr (dump_file, val, 0); | |
1049 | fprintf (dump_file, "\n"); | |
1050 | } | |
1051 | ||
1052 | prop_stats.num_pred_folded++; | |
1053 | *pred_p = val; | |
1054 | return true; | |
1055 | } | |
1056 | ||
1057 | return false; | |
0bca51f0 DN |
1058 | } |
1059 | ||
1060 | ||
227858d1 DN |
1061 | /* Perform final substitution and folding of propagated values. |
1062 | ||
1063 | PROP_VALUE[I] contains the single value that should be substituted | |
1064 | at every use of SSA name N_I. If PROP_VALUE is NULL, no values are | |
1065 | substituted. | |
1066 | ||
1067 | If USE_RANGES_P is true, statements that contain predicate | |
1068 | expressions are evaluated with a call to vrp_evaluate_conditional. | |
1069 | This will only give meaningful results when called from tree-vrp.c | |
1070 | (the information used by vrp_evaluate_conditional is built by the | |
1071 | VRP pass). */ | |
0bca51f0 DN |
1072 | |
1073 | void | |
227858d1 | 1074 | substitute_and_fold (prop_value_t *prop_value, bool use_ranges_p) |
0bca51f0 DN |
1075 | { |
1076 | basic_block bb; | |
1077 | ||
227858d1 DN |
1078 | if (prop_value == NULL && !use_ranges_p) |
1079 | return; | |
1080 | ||
0bca51f0 | 1081 | if (dump_file && (dump_flags & TDF_DETAILS)) |
227858d1 | 1082 | fprintf (dump_file, "\nSubstituing values and folding statements\n\n"); |
0bca51f0 DN |
1083 | |
1084 | memset (&prop_stats, 0, sizeof (prop_stats)); | |
1085 | ||
1086 | /* Substitute values in every statement of every basic block. */ | |
1087 | FOR_EACH_BB (bb) | |
1088 | { | |
1089 | block_stmt_iterator i; | |
1090 | tree phi; | |
1091 | ||
227858d1 DN |
1092 | /* Propagate known values into PHI nodes. */ |
1093 | if (prop_value) | |
1094 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) | |
0bca51f0 DN |
1095 | replace_phi_args_in (phi, prop_value); |
1096 | ||
0bca51f0 DN |
1097 | for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i)) |
1098 | { | |
1099 | bool replaced_address, did_replace; | |
227858d1 | 1100 | tree prev_stmt = NULL; |
0bca51f0 DN |
1101 | tree stmt = bsi_stmt (i); |
1102 | ||
227858d1 DN |
1103 | /* Ignore ASSERT_EXPRs. They are used by VRP to generate |
1104 | range information for names and they are discarded | |
1105 | afterwards. */ | |
1106 | if (TREE_CODE (stmt) == MODIFY_EXPR | |
1107 | && TREE_CODE (TREE_OPERAND (stmt, 1)) == ASSERT_EXPR) | |
1108 | continue; | |
1109 | ||
0bca51f0 DN |
1110 | /* Replace the statement with its folded version and mark it |
1111 | folded. */ | |
227858d1 DN |
1112 | did_replace = false; |
1113 | replaced_address = false; | |
0bca51f0 | 1114 | if (dump_file && (dump_flags & TDF_DETAILS)) |
227858d1 DN |
1115 | prev_stmt = unshare_expr (stmt); |
1116 | ||
1117 | /* If we have range information, see if we can fold | |
1118 | predicate expressions. */ | |
1119 | if (use_ranges_p) | |
1a557723 JL |
1120 | { |
1121 | did_replace = fold_predicate_in (stmt); | |
1122 | ||
1123 | /* Some statements may be simplified using ranges. For | |
1124 | example, division may be replaced by shifts, modulo | |
1125 | replaced with bitwise and, etc. */ | |
1126 | simplify_stmt_using_ranges (stmt); | |
1127 | } | |
227858d1 DN |
1128 | |
1129 | if (prop_value) | |
0bca51f0 | 1130 | { |
227858d1 DN |
1131 | /* Only replace real uses if we couldn't fold the |
1132 | statement using value range information (value range | |
1133 | information is not collected on virtuals, so we only | |
1134 | need to check this for real uses). */ | |
1135 | if (!did_replace) | |
1136 | did_replace |= replace_uses_in (stmt, &replaced_address, | |
1137 | prop_value); | |
1138 | ||
1139 | did_replace |= replace_vuses_in (stmt, &replaced_address, | |
1140 | prop_value); | |
0bca51f0 DN |
1141 | } |
1142 | ||
227858d1 | 1143 | /* If we made a replacement, fold and cleanup the statement. */ |
0bca51f0 DN |
1144 | if (did_replace) |
1145 | { | |
af47810a | 1146 | tree old_stmt = stmt; |
6cedb4ac JL |
1147 | tree rhs; |
1148 | ||
0bca51f0 | 1149 | fold_stmt (bsi_stmt_ptr (i)); |
6cedb4ac | 1150 | stmt = bsi_stmt (i); |
0bca51f0 DN |
1151 | |
1152 | /* If we folded a builtin function, we'll likely | |
1153 | need to rename VDEFs. */ | |
1154 | mark_new_vars_to_rename (stmt); | |
1155 | ||
1156 | /* If we cleaned up EH information from the statement, | |
1157 | remove EH edges. */ | |
af47810a | 1158 | if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt)) |
0bca51f0 | 1159 | tree_purge_dead_eh_edges (bb); |
6cedb4ac JL |
1160 | |
1161 | rhs = get_rhs (stmt); | |
1162 | if (TREE_CODE (rhs) == ADDR_EXPR) | |
1163 | recompute_tree_invarant_for_addr_expr (rhs); | |
0bca51f0 | 1164 | |
227858d1 DN |
1165 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1166 | { | |
1167 | fprintf (dump_file, "Folded statement: "); | |
1168 | print_generic_stmt (dump_file, prev_stmt, TDF_SLIM); | |
1169 | fprintf (dump_file, " into: "); | |
1170 | print_generic_stmt (dump_file, stmt, TDF_SLIM); | |
1171 | fprintf (dump_file, "\n"); | |
1172 | } | |
0bca51f0 DN |
1173 | } |
1174 | } | |
1175 | } | |
1176 | ||
1177 | if (dump_file && (dump_flags & TDF_STATS)) | |
1178 | { | |
1179 | fprintf (dump_file, "Constants propagated: %6ld\n", | |
1180 | prop_stats.num_const_prop); | |
1181 | fprintf (dump_file, "Copies propagated: %6ld\n", | |
1182 | prop_stats.num_copy_prop); | |
227858d1 DN |
1183 | fprintf (dump_file, "Predicates folded: %6ld\n", |
1184 | prop_stats.num_pred_folded); | |
0bca51f0 DN |
1185 | } |
1186 | } | |
227858d1 | 1187 | |
750628d8 | 1188 | #include "gt-tree-ssa-propagate.h" |