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5f718c29 | 1 | /* Routines for discovering and unpropagating edge equivalences. |
d353bf18 | 2 | Copyright (C) 2005-2015 Free Software Foundation, Inc. |
5f718c29 | 3 | |
4 | This file is part of GCC. | |
5 | ||
6 | GCC is free software; you can redistribute it and/or modify | |
7 | it 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) |
5f718c29 | 9 | any later version. |
10 | ||
11 | GCC is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
8c4c00c1 | 17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ | |
5f718c29 | 19 | |
20 | #include "config.h" | |
21 | #include "system.h" | |
22 | #include "coretypes.h" | |
23 | #include "tm.h" | |
24 | #include "tree.h" | |
9ed99284 | 25 | #include "stor-layout.h" |
5f718c29 | 26 | #include "flags.h" |
5f718c29 | 27 | #include "tm_p.h" |
94ea8568 | 28 | #include "predict.h" |
29 | #include "vec.h" | |
a3020f2f | 30 | #include "hashtab.h" |
31 | #include "hash-set.h" | |
a3020f2f | 32 | #include "machmode.h" |
33 | #include "hard-reg-set.h" | |
34 | #include "input.h" | |
5f718c29 | 35 | #include "function.h" |
94ea8568 | 36 | #include "dominance.h" |
37 | #include "cfg.h" | |
38 | #include "cfganal.h" | |
39 | #include "basic-block.h" | |
bc61cadb | 40 | #include "hash-table.h" |
d62dd039 | 41 | #include "hash-map.h" |
bc61cadb | 42 | #include "tree-ssa-alias.h" |
43 | #include "internal-fn.h" | |
44 | #include "gimple-expr.h" | |
45 | #include "is-a.h" | |
073c1fd5 | 46 | #include "gimple.h" |
dcf1a1ec | 47 | #include "gimple-iterator.h" |
073c1fd5 | 48 | #include "gimple-ssa.h" |
49 | #include "tree-cfg.h" | |
50 | #include "tree-phinodes.h" | |
51 | #include "ssa-iterators.h" | |
5f718c29 | 52 | #include "domwalk.h" |
5f718c29 | 53 | #include "tree-pass.h" |
54 | #include "tree-ssa-propagate.h" | |
5f718c29 | 55 | |
56 | /* The basic structure describing an equivalency created by traversing | |
57 | an edge. Traversing the edge effectively means that we can assume | |
58 | that we've seen an assignment LHS = RHS. */ | |
59 | struct edge_equivalency | |
60 | { | |
61 | tree rhs; | |
62 | tree lhs; | |
63 | }; | |
64 | ||
65 | /* This routine finds and records edge equivalences for every edge | |
66 | in the CFG. | |
67 | ||
68 | When complete, each edge that creates an equivalency will have an | |
48e1416a | 69 | EDGE_EQUIVALENCY structure hanging off the edge's AUX field. |
5f718c29 | 70 | The caller is responsible for freeing the AUX fields. */ |
71 | ||
72 | static void | |
73 | associate_equivalences_with_edges (void) | |
74 | { | |
75 | basic_block bb; | |
76 | ||
77 | /* Walk over each block. If the block ends with a control statement, | |
78 | then it might create a useful equivalence. */ | |
fc00614f | 79 | FOR_EACH_BB_FN (bb, cfun) |
5f718c29 | 80 | { |
75a70cf9 | 81 | gimple_stmt_iterator gsi = gsi_last_bb (bb); |
82 | gimple stmt; | |
5f718c29 | 83 | |
84 | /* If the block does not end with a COND_EXPR or SWITCH_EXPR | |
85 | then there is nothing to do. */ | |
75a70cf9 | 86 | if (gsi_end_p (gsi)) |
5f718c29 | 87 | continue; |
88 | ||
75a70cf9 | 89 | stmt = gsi_stmt (gsi); |
5f718c29 | 90 | |
91 | if (!stmt) | |
92 | continue; | |
93 | ||
94 | /* A COND_EXPR may create an equivalency in a variety of different | |
95 | ways. */ | |
75a70cf9 | 96 | if (gimple_code (stmt) == GIMPLE_COND) |
5f718c29 | 97 | { |
5f718c29 | 98 | edge true_edge; |
99 | edge false_edge; | |
100 | struct edge_equivalency *equivalency; | |
75a70cf9 | 101 | enum tree_code code = gimple_cond_code (stmt); |
5f718c29 | 102 | |
103 | extract_true_false_edges_from_block (bb, &true_edge, &false_edge); | |
104 | ||
5f718c29 | 105 | /* Equality tests may create one or two equivalences. */ |
75a70cf9 | 106 | if (code == EQ_EXPR || code == NE_EXPR) |
5f718c29 | 107 | { |
75a70cf9 | 108 | tree op0 = gimple_cond_lhs (stmt); |
109 | tree op1 = gimple_cond_rhs (stmt); | |
5f718c29 | 110 | |
111 | /* Special case comparing booleans against a constant as we | |
112 | know the value of OP0 on both arms of the branch. i.e., we | |
113 | can record an equivalence for OP0 rather than COND. */ | |
114 | if (TREE_CODE (op0) == SSA_NAME | |
932540b6 | 115 | && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op0) |
5f718c29 | 116 | && TREE_CODE (TREE_TYPE (op0)) == BOOLEAN_TYPE |
117 | && is_gimple_min_invariant (op1)) | |
118 | { | |
75a70cf9 | 119 | if (code == EQ_EXPR) |
5f718c29 | 120 | { |
945865c5 | 121 | equivalency = XNEW (struct edge_equivalency); |
5f718c29 | 122 | equivalency->lhs = op0; |
123 | equivalency->rhs = (integer_zerop (op1) | |
124 | ? boolean_false_node | |
125 | : boolean_true_node); | |
126 | true_edge->aux = equivalency; | |
127 | ||
945865c5 | 128 | equivalency = XNEW (struct edge_equivalency); |
5f718c29 | 129 | equivalency->lhs = op0; |
130 | equivalency->rhs = (integer_zerop (op1) | |
131 | ? boolean_true_node | |
132 | : boolean_false_node); | |
133 | false_edge->aux = equivalency; | |
134 | } | |
135 | else | |
136 | { | |
945865c5 | 137 | equivalency = XNEW (struct edge_equivalency); |
5f718c29 | 138 | equivalency->lhs = op0; |
139 | equivalency->rhs = (integer_zerop (op1) | |
140 | ? boolean_true_node | |
141 | : boolean_false_node); | |
142 | true_edge->aux = equivalency; | |
143 | ||
945865c5 | 144 | equivalency = XNEW (struct edge_equivalency); |
5f718c29 | 145 | equivalency->lhs = op0; |
146 | equivalency->rhs = (integer_zerop (op1) | |
147 | ? boolean_false_node | |
148 | : boolean_true_node); | |
149 | false_edge->aux = equivalency; | |
150 | } | |
151 | } | |
152 | ||
024e445d | 153 | else if (TREE_CODE (op0) == SSA_NAME |
154 | && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op0) | |
155 | && (is_gimple_min_invariant (op1) | |
156 | || (TREE_CODE (op1) == SSA_NAME | |
157 | && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op1)))) | |
5f718c29 | 158 | { |
159 | /* For IEEE, -0.0 == 0.0, so we don't necessarily know | |
160 | the sign of a variable compared against zero. If | |
161 | we're honoring signed zeros, then we cannot record | |
162 | this value unless we know that the value is nonzero. */ | |
fe994837 | 163 | if (HONOR_SIGNED_ZEROS (op0) |
5f718c29 | 164 | && (TREE_CODE (op1) != REAL_CST |
165 | || REAL_VALUES_EQUAL (dconst0, TREE_REAL_CST (op1)))) | |
166 | continue; | |
167 | ||
945865c5 | 168 | equivalency = XNEW (struct edge_equivalency); |
5f718c29 | 169 | equivalency->lhs = op0; |
170 | equivalency->rhs = op1; | |
75a70cf9 | 171 | if (code == EQ_EXPR) |
5f718c29 | 172 | true_edge->aux = equivalency; |
48e1416a | 173 | else |
5f718c29 | 174 | false_edge->aux = equivalency; |
175 | ||
176 | } | |
177 | } | |
178 | ||
179 | /* ??? TRUTH_NOT_EXPR can create an equivalence too. */ | |
180 | } | |
181 | ||
182 | /* For a SWITCH_EXPR, a case label which represents a single | |
183 | value and which is the only case label which reaches the | |
184 | target block creates an equivalence. */ | |
75a70cf9 | 185 | else if (gimple_code (stmt) == GIMPLE_SWITCH) |
5f718c29 | 186 | { |
1a91d914 | 187 | gswitch *switch_stmt = as_a <gswitch *> (stmt); |
188 | tree cond = gimple_switch_index (switch_stmt); | |
5f718c29 | 189 | |
932540b6 | 190 | if (TREE_CODE (cond) == SSA_NAME |
191 | && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (cond)) | |
5f718c29 | 192 | { |
1a91d914 | 193 | int i, n_labels = gimple_switch_num_labels (switch_stmt); |
fe672ac0 | 194 | tree *info = XCNEWVEC (tree, last_basic_block_for_fn (cfun)); |
5f718c29 | 195 | |
196 | /* Walk over the case label vector. Record blocks | |
197 | which are reached by a single case label which represents | |
198 | a single value. */ | |
199 | for (i = 0; i < n_labels; i++) | |
200 | { | |
1a91d914 | 201 | tree label = gimple_switch_label (switch_stmt, i); |
5f718c29 | 202 | basic_block bb = label_to_block (CASE_LABEL (label)); |
203 | ||
5f718c29 | 204 | if (CASE_HIGH (label) |
205 | || !CASE_LOW (label) | |
206 | || info[bb->index]) | |
207 | info[bb->index] = error_mark_node; | |
208 | else | |
209 | info[bb->index] = label; | |
210 | } | |
211 | ||
212 | /* Now walk over the blocks to determine which ones were | |
213 | marked as being reached by a useful case label. */ | |
a28770e1 | 214 | for (i = 0; i < n_basic_blocks_for_fn (cfun); i++) |
5f718c29 | 215 | { |
216 | tree node = info[i]; | |
217 | ||
218 | if (node != NULL | |
219 | && node != error_mark_node) | |
220 | { | |
221 | tree x = fold_convert (TREE_TYPE (cond), CASE_LOW (node)); | |
222 | struct edge_equivalency *equivalency; | |
223 | ||
224 | /* Record an equivalency on the edge from BB to basic | |
225 | block I. */ | |
945865c5 | 226 | equivalency = XNEW (struct edge_equivalency); |
5f718c29 | 227 | equivalency->rhs = x; |
228 | equivalency->lhs = cond; | |
f5a6b05f | 229 | find_edge (bb, BASIC_BLOCK_FOR_FN (cfun, i))->aux = |
230 | equivalency; | |
5f718c29 | 231 | } |
232 | } | |
233 | free (info); | |
234 | } | |
235 | } | |
236 | ||
237 | } | |
238 | } | |
239 | ||
240 | ||
241 | /* Translating out of SSA sometimes requires inserting copies and | |
242 | constant initializations on edges to eliminate PHI nodes. | |
243 | ||
244 | In some cases those copies and constant initializations are | |
245 | redundant because the target already has the value on the | |
246 | RHS of the assignment. | |
247 | ||
248 | We previously tried to catch these cases after translating | |
249 | out of SSA form. However, that code often missed cases. Worse | |
250 | yet, the cases it missed were also often missed by the RTL | |
251 | optimizers. Thus the resulting code had redundant instructions. | |
252 | ||
253 | This pass attempts to detect these situations before translating | |
254 | out of SSA form. | |
255 | ||
256 | The key concept that this pass is built upon is that these | |
257 | redundant copies and constant initializations often occur | |
258 | due to constant/copy propagating equivalences resulting from | |
259 | COND_EXPRs and SWITCH_EXPRs. | |
260 | ||
261 | We want to do those propagations as they can sometimes allow | |
25f6297d | 262 | the SSA optimizers to do a better job. However, in the cases |
5f718c29 | 263 | where such propagations do not result in further optimization, |
264 | we would like to "undo" the propagation to avoid the redundant | |
265 | copies and constant initializations. | |
266 | ||
267 | This pass works by first associating equivalences with edges in | |
268 | the CFG. For example, the edge leading from a SWITCH_EXPR to | |
269 | its associated CASE_LABEL will have an equivalency between | |
270 | SWITCH_COND and the value in the case label. | |
271 | ||
272 | Once we have found the edge equivalences, we proceed to walk | |
273 | the CFG in dominator order. As we traverse edges we record | |
274 | equivalences associated with those edges we traverse. | |
275 | ||
276 | When we encounter a PHI node, we walk its arguments to see if we | |
277 | have an equivalence for the PHI argument. If so, then we replace | |
278 | the argument. | |
279 | ||
280 | Equivalences are looked up based on their value (think of it as | |
281 | the RHS of an assignment). A value may be an SSA_NAME or an | |
282 | invariant. We may have several SSA_NAMEs with the same value, | |
283 | so with each value we have a list of SSA_NAMEs that have the | |
284 | same value. */ | |
285 | ||
5f718c29 | 286 | |
5f718c29 | 287 | /* Main structure for recording equivalences into our hash table. */ |
288 | struct equiv_hash_elt | |
289 | { | |
290 | /* The value/key of this entry. */ | |
291 | tree value; | |
292 | ||
293 | /* List of SSA_NAMEs which have the same value/key. */ | |
f1f41a6c | 294 | vec<tree> equivalences; |
5f718c29 | 295 | }; |
296 | ||
d9dd21a8 | 297 | /* Value to ssa name equivalence hashtable helpers. */ |
5f718c29 | 298 | |
d62dd039 | 299 | struct val_ssa_equiv_hash_traits : default_hashmap_traits |
d9dd21a8 | 300 | { |
d62dd039 | 301 | static inline hashval_t hash (tree); |
302 | static inline bool equal_keys (tree, tree); | |
303 | template<typename T> static inline void remove (T &); | |
d9dd21a8 | 304 | }; |
5f718c29 | 305 | |
d9dd21a8 | 306 | inline hashval_t |
d62dd039 | 307 | val_ssa_equiv_hash_traits::hash (tree value) |
5f718c29 | 308 | { |
5f718c29 | 309 | return iterative_hash_expr (value, 0); |
310 | } | |
311 | ||
d9dd21a8 | 312 | inline bool |
d62dd039 | 313 | val_ssa_equiv_hash_traits::equal_keys (tree value1, tree value2) |
5f718c29 | 314 | { |
5f718c29 | 315 | return operand_equal_p (value1, value2, 0); |
316 | } | |
317 | ||
96a7ab57 | 318 | /* Free an instance of equiv_hash_elt. */ |
319 | ||
d62dd039 | 320 | template<typename T> |
d9dd21a8 | 321 | inline void |
d62dd039 | 322 | val_ssa_equiv_hash_traits::remove (T &elt) |
96a7ab57 | 323 | { |
d62dd039 | 324 | elt.m_value.release (); |
96a7ab57 | 325 | } |
326 | ||
d9dd21a8 | 327 | /* Global hash table implementing a mapping from invariant values |
328 | to a list of SSA_NAMEs which have the same value. We might be | |
329 | able to reuse tree-vn for this code. */ | |
d62dd039 | 330 | static hash_map<tree, vec<tree>, val_ssa_equiv_hash_traits> *val_ssa_equiv; |
d9dd21a8 | 331 | |
d9dd21a8 | 332 | static void uncprop_into_successor_phis (basic_block); |
333 | ||
5f718c29 | 334 | /* Remove the most recently recorded equivalency for VALUE. */ |
335 | ||
336 | static void | |
337 | remove_equivalence (tree value) | |
338 | { | |
d62dd039 | 339 | val_ssa_equiv->get (value)->pop (); |
5f718c29 | 340 | } |
341 | ||
342 | /* Record EQUIVALENCE = VALUE into our hash table. */ | |
343 | ||
344 | static void | |
345 | record_equiv (tree value, tree equivalence) | |
346 | { | |
d62dd039 | 347 | val_ssa_equiv->get_or_insert (value).safe_push (equivalence); |
5f718c29 | 348 | } |
349 | ||
54c91640 | 350 | class uncprop_dom_walker : public dom_walker |
351 | { | |
352 | public: | |
e85cf4e5 | 353 | uncprop_dom_walker (cdi_direction direction) : dom_walker (direction) {} |
54c91640 | 354 | |
355 | virtual void before_dom_children (basic_block); | |
356 | virtual void after_dom_children (basic_block); | |
357 | ||
358 | private: | |
359 | ||
ae84f584 | 360 | /* As we enter each block we record the value for any edge equivalency |
361 | leading to this block. If no such edge equivalency exists, then we | |
362 | record NULL. These equivalences are live until we leave the dominator | |
363 | subtree rooted at the block where we record the equivalency. */ | |
4997014d | 364 | auto_vec<tree, 2> m_equiv_stack; |
54c91640 | 365 | }; |
366 | ||
5f718c29 | 367 | /* We have finished processing the dominator children of BB, perform |
368 | any finalization actions in preparation for leaving this node in | |
369 | the dominator tree. */ | |
370 | ||
54c91640 | 371 | void |
372 | uncprop_dom_walker::after_dom_children (basic_block bb ATTRIBUTE_UNUSED) | |
5f718c29 | 373 | { |
5f718c29 | 374 | /* Pop the topmost value off the equiv stack. */ |
ae84f584 | 375 | tree value = m_equiv_stack.pop (); |
5f718c29 | 376 | |
377 | /* If that value was non-null, then pop the topmost equivalency off | |
378 | its equivalency stack. */ | |
379 | if (value != NULL) | |
380 | remove_equivalence (value); | |
381 | } | |
382 | ||
383 | /* Unpropagate values from PHI nodes in successor blocks of BB. */ | |
384 | ||
385 | static void | |
6bf320fb | 386 | uncprop_into_successor_phis (basic_block bb) |
5f718c29 | 387 | { |
388 | edge e; | |
389 | edge_iterator ei; | |
390 | ||
391 | /* For each successor edge, first temporarily record any equivalence | |
392 | on that edge. Then unpropagate values in any PHI nodes at the | |
393 | destination of the edge. Then remove the temporary equivalence. */ | |
394 | FOR_EACH_EDGE (e, ei, bb->succs) | |
395 | { | |
75a70cf9 | 396 | gimple_seq phis = phi_nodes (e->dest); |
397 | gimple_stmt_iterator gsi; | |
5f718c29 | 398 | |
399 | /* If there are no PHI nodes in this destination, then there is | |
400 | no sense in recording any equivalences. */ | |
be2517f5 | 401 | if (gimple_seq_empty_p (phis)) |
5f718c29 | 402 | continue; |
403 | ||
404 | /* Record any equivalency associated with E. */ | |
405 | if (e->aux) | |
406 | { | |
945865c5 | 407 | struct edge_equivalency *equiv = (struct edge_equivalency *) e->aux; |
5f718c29 | 408 | record_equiv (equiv->rhs, equiv->lhs); |
409 | } | |
410 | ||
411 | /* Walk over the PHI nodes, unpropagating values. */ | |
75a70cf9 | 412 | for (gsi = gsi_start (phis) ; !gsi_end_p (gsi); gsi_next (&gsi)) |
5f718c29 | 413 | { |
75a70cf9 | 414 | gimple phi = gsi_stmt (gsi); |
5f718c29 | 415 | tree arg = PHI_ARG_DEF (phi, e->dest_idx); |
ec11736b | 416 | tree res = PHI_RESULT (phi); |
5f718c29 | 417 | |
f82f0ea5 | 418 | /* If the argument is not an invariant and can be potentially |
419 | coalesced with the result, then there's no point in | |
420 | un-propagating the argument. */ | |
5f718c29 | 421 | if (!is_gimple_min_invariant (arg) |
f82f0ea5 | 422 | && gimple_can_coalesce_p (arg, res)) |
5f718c29 | 423 | continue; |
424 | ||
425 | /* Lookup this argument's value in the hash table. */ | |
d62dd039 | 426 | vec<tree> *equivalences = val_ssa_equiv->get (arg); |
427 | if (equivalences) | |
5f718c29 | 428 | { |
5f718c29 | 429 | /* Walk every equivalence with the same value. If we find |
f82f0ea5 | 430 | one that can potentially coalesce with the PHI rsult, |
5f718c29 | 431 | then replace the value in the argument with its equivalent |
25f6297d | 432 | SSA_NAME. Use the most recent equivalence as hopefully |
5f718c29 | 433 | that results in shortest lifetimes. */ |
d62dd039 | 434 | for (int j = equivalences->length () - 1; j >= 0; j--) |
5f718c29 | 435 | { |
d62dd039 | 436 | tree equiv = (*equivalences)[j]; |
5f718c29 | 437 | |
f82f0ea5 | 438 | if (gimple_can_coalesce_p (equiv, res)) |
5f718c29 | 439 | { |
440 | SET_PHI_ARG_DEF (phi, e->dest_idx, equiv); | |
441 | break; | |
442 | } | |
443 | } | |
444 | } | |
445 | } | |
446 | ||
447 | /* If we had an equivalence associated with this edge, remove it. */ | |
448 | if (e->aux) | |
449 | { | |
945865c5 | 450 | struct edge_equivalency *equiv = (struct edge_equivalency *) e->aux; |
5f718c29 | 451 | remove_equivalence (equiv->rhs); |
452 | } | |
453 | } | |
454 | } | |
455 | ||
456 | /* Ignoring loop backedges, if BB has precisely one incoming edge then | |
457 | return that edge. Otherwise return NULL. */ | |
458 | static edge | |
459 | single_incoming_edge_ignoring_loop_edges (basic_block bb) | |
460 | { | |
461 | edge retval = NULL; | |
462 | edge e; | |
463 | edge_iterator ei; | |
464 | ||
465 | FOR_EACH_EDGE (e, ei, bb->preds) | |
466 | { | |
467 | /* A loop back edge can be identified by the destination of | |
468 | the edge dominating the source of the edge. */ | |
469 | if (dominated_by_p (CDI_DOMINATORS, e->src, e->dest)) | |
470 | continue; | |
471 | ||
472 | /* If we have already seen a non-loop edge, then we must have | |
473 | multiple incoming non-loop edges and thus we return NULL. */ | |
474 | if (retval) | |
475 | return NULL; | |
476 | ||
477 | /* This is the first non-loop incoming edge we have found. Record | |
478 | it. */ | |
479 | retval = e; | |
480 | } | |
481 | ||
482 | return retval; | |
483 | } | |
484 | ||
54c91640 | 485 | void |
486 | uncprop_dom_walker::before_dom_children (basic_block bb) | |
5f718c29 | 487 | { |
488 | basic_block parent; | |
489 | edge e; | |
490 | bool recorded = false; | |
491 | ||
492 | /* If this block is dominated by a single incoming edge and that edge | |
493 | has an equivalency, then record the equivalency and push the | |
494 | VALUE onto EQUIV_STACK. Else push a NULL entry on EQUIV_STACK. */ | |
495 | parent = get_immediate_dominator (CDI_DOMINATORS, bb); | |
496 | if (parent) | |
497 | { | |
498 | e = single_incoming_edge_ignoring_loop_edges (bb); | |
499 | ||
500 | if (e && e->src == parent && e->aux) | |
501 | { | |
945865c5 | 502 | struct edge_equivalency *equiv = (struct edge_equivalency *) e->aux; |
5f718c29 | 503 | |
504 | record_equiv (equiv->rhs, equiv->lhs); | |
ae84f584 | 505 | m_equiv_stack.safe_push (equiv->rhs); |
5f718c29 | 506 | recorded = true; |
507 | } | |
508 | } | |
509 | ||
510 | if (!recorded) | |
ae84f584 | 511 | m_equiv_stack.safe_push (NULL_TREE); |
6bf320fb | 512 | |
513 | uncprop_into_successor_phis (bb); | |
5f718c29 | 514 | } |
515 | ||
cbe8bda8 | 516 | namespace { |
517 | ||
518 | const pass_data pass_data_uncprop = | |
5f718c29 | 519 | { |
cbe8bda8 | 520 | GIMPLE_PASS, /* type */ |
521 | "uncprop", /* name */ | |
522 | OPTGROUP_NONE, /* optinfo_flags */ | |
cbe8bda8 | 523 | TV_TREE_SSA_UNCPROP, /* tv_id */ |
524 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
525 | 0, /* properties_provided */ | |
526 | 0, /* properties_destroyed */ | |
527 | 0, /* todo_flags_start */ | |
8b88439e | 528 | 0, /* todo_flags_finish */ |
5f718c29 | 529 | }; |
cbe8bda8 | 530 | |
531 | class pass_uncprop : public gimple_opt_pass | |
532 | { | |
533 | public: | |
9af5ce0c | 534 | pass_uncprop (gcc::context *ctxt) |
535 | : gimple_opt_pass (pass_data_uncprop, ctxt) | |
cbe8bda8 | 536 | {} |
537 | ||
538 | /* opt_pass methods: */ | |
ae84f584 | 539 | opt_pass * clone () { return new pass_uncprop (m_ctxt); } |
31315c24 | 540 | virtual bool gate (function *) { return flag_tree_dom != 0; } |
65b0537f | 541 | virtual unsigned int execute (function *); |
cbe8bda8 | 542 | |
543 | }; // class pass_uncprop | |
544 | ||
65b0537f | 545 | unsigned int |
546 | pass_uncprop::execute (function *fun) | |
547 | { | |
548 | basic_block bb; | |
549 | ||
550 | associate_equivalences_with_edges (); | |
551 | ||
552 | /* Create our global data structures. */ | |
d62dd039 | 553 | val_ssa_equiv |
554 | = new hash_map<tree, vec<tree>, val_ssa_equiv_hash_traits> (1024); | |
65b0537f | 555 | |
556 | /* We're going to do a dominator walk, so ensure that we have | |
557 | dominance information. */ | |
558 | calculate_dominance_info (CDI_DOMINATORS); | |
559 | ||
560 | /* Recursively walk the dominator tree undoing unprofitable | |
561 | constant/copy propagations. */ | |
562 | uncprop_dom_walker (CDI_DOMINATORS).walk (fun->cfg->x_entry_block_ptr); | |
563 | ||
564 | /* we just need to empty elements out of the hash table, and cleanup the | |
565 | AUX field on the edges. */ | |
c1f445d2 | 566 | delete val_ssa_equiv; |
567 | val_ssa_equiv = NULL; | |
65b0537f | 568 | FOR_EACH_BB_FN (bb, fun) |
569 | { | |
570 | edge e; | |
571 | edge_iterator ei; | |
572 | ||
573 | FOR_EACH_EDGE (e, ei, bb->succs) | |
574 | { | |
575 | if (e->aux) | |
576 | { | |
577 | free (e->aux); | |
578 | e->aux = NULL; | |
579 | } | |
580 | } | |
581 | } | |
582 | return 0; | |
583 | } | |
584 | ||
cbe8bda8 | 585 | } // anon namespace |
586 | ||
587 | gimple_opt_pass * | |
588 | make_pass_uncprop (gcc::context *ctxt) | |
589 | { | |
590 | return new pass_uncprop (ctxt); | |
591 | } |