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1 : : /* Header file for the value range relational processing.
2 : : Copyright (C) 2020-2025 Free Software Foundation, Inc.
3 : : Contributed by Andrew MacLeod <amacleod@redhat.com>
4 : :
5 : : This file is part of GCC.
6 : :
7 : : GCC is free software; you can redistribute it and/or modify it under
8 : : the terms of the GNU General Public License as published by the Free
9 : : Software Foundation; either version 3, or (at your option) any later
10 : : version.
11 : :
12 : : GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 : : 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 COPYING3. If not see
19 : : <http://www.gnu.org/licenses/>. */
20 : :
21 : : #ifndef GCC_VALUE_RELATION_H
22 : : #define GCC_VALUE_RELATION_H
23 : :
24 : :
25 : : // This file provides access to a relation oracle which can be used to
26 : : // maintain and query relations and equivalences between SSA_NAMES.
27 : : //
28 : : // The general range_query object provided in value-query.h provides
29 : : // access to an oracle, if one is available, via the oracle() method.
30 : : // There are also a couple of access routines provided, which even if there is
31 : : // no oracle, will return the default VREL_VARYING no relation.
32 : : //
33 : : // Typically, when a ranger object is active, there will be an oracle, and
34 : : // any information available can be directly queried. Ranger also sets and
35 : : // utilizes the relation information to enhance it's range calculations, this
36 : : // is totally transparent to the client, and they are free to make queries.
37 : : //
38 : : // relation_kind is a new enum which represents the different relations,
39 : : // often with a direct mapping to tree codes. ie VREL_EQ is equivalent to
40 : : // EQ_EXPR.
41 : : //
42 : : // A query is made requesting the relation between SSA1 and SSA@ in a basic
43 : : // block, or on an edge, the possible return values are:
44 : : //
45 : : // VREL_EQ, VREL_NE, VREL_LT, VREL_LE, VREL_GT, and VREL_GE mean the same.
46 : : // VREL_VARYING : No relation between the 2 names.
47 : : // VREL_UNDEFINED : Impossible relation (ie, A < B && A > B)
48 : : //
49 : : // The oracle maintains VREL_EQ relations with equivalency sets, so if a
50 : : // relation comes back VREL_EQ, it is also possible to query the set of
51 : : // equivalencies. These are basically bitmaps over ssa_names. An iterator is
52 : : // provided later for this activity.
53 : : //
54 : : // Relations are maintained via the dominance trees and are optimized assuming
55 : : // they are registered in dominance order. When a new relation is added, it
56 : : // is intersected with whatever existing relation exists in the dominance tree
57 : : // and registered at the specified block.
58 : :
59 : :
60 : : // These codes are arranged such that VREL_VARYING is the first code, and all
61 : : // the rest are contiguous.
62 : :
63 : : typedef enum relation_kind_t
64 : : {
65 : : VREL_VARYING = 0, // No known relation, AKA varying.
66 : : VREL_UNDEFINED, // Impossible relation, ie (r1 < r2) && (r2 > r1)
67 : : VREL_LT, // r1 < r2
68 : : VREL_LE, // r1 <= r2
69 : : VREL_GT, // r1 > r2
70 : : VREL_GE, // r1 >= r2
71 : : VREL_EQ, // r1 == r2
72 : : VREL_NE, // r1 != r2
73 : : VREL_PE8, // 8 bit partial equivalency
74 : : VREL_PE16, // 16 bit partial equivalency
75 : : VREL_PE32, // 32 bit partial equivalency
76 : : VREL_PE64, // 64 bit partial equivalency
77 : : VREL_LAST // terminate, not a real relation.
78 : : } relation_kind;
79 : :
80 : : // General relation kind transformations.
81 : : relation_kind relation_union (relation_kind r1, relation_kind r2);
82 : : relation_kind relation_intersect (relation_kind r1, relation_kind r2);
83 : : relation_kind relation_negate (relation_kind r);
84 : : relation_kind relation_swap (relation_kind r);
85 : 4679570 : inline bool relation_lt_le_gt_ge_p (relation_kind r)
86 : 4679570 : { return (r >= VREL_LT && r <= VREL_GE); }
87 : 160476080 : inline bool relation_partial_equiv_p (relation_kind r)
88 : 105281041 : { return (r >= VREL_PE8 && r <= VREL_PE64); }
89 : 134890366 : inline bool relation_equiv_p (relation_kind r)
90 : 134890366 : { return r == VREL_EQ || relation_partial_equiv_p (r); }
91 : :
92 : : void print_relation (FILE *f, relation_kind rel);
93 : :
94 : : // Adjust range as an equivalence.
95 : : void adjust_equivalence_range (vrange &range);
96 : :
97 : 53129811 : class relation_oracle
98 : : {
99 : : public:
100 : 53413831 : virtual ~relation_oracle () { }
101 : :
102 : : // register a relation between 2 ssa names.
103 : : void record (gimple *, relation_kind, tree, tree);
104 : : void record (edge, relation_kind, tree, tree);
105 : 600497 : virtual void record (basic_block, relation_kind, tree, tree) { }
106 : :
107 : : // Query if there is any relation between SSA1 and SSA2.
108 : : relation_kind query (gimple *s, tree ssa1, tree ssa2);
109 : : relation_kind query (edge e, tree ssa1, tree ssa2);
110 : 12012467 : virtual relation_kind query (basic_block, tree, tree) { return VREL_VARYING; }
111 : :
112 : 0 : virtual void dump (FILE *, basic_block) const { }
113 : 0 : virtual void dump (FILE *) const { }
114 : : void debug () const;
115 : : protected:
116 : : friend class equiv_relation_iterator;
117 : : friend class block_relation_iterator;
118 : 0 : virtual class relation_chain *next_relation (basic_block,
119 : : relation_chain *,
120 : : tree) const
121 : 0 : { return NULL; }
122 : : // Return equivalency set for an SSA name in a basic block.
123 : 0 : virtual const_bitmap equiv_set (tree, basic_block) { return NULL; }
124 : : // Return partial equivalency record for an SSA name.
125 : 0 : virtual const class pe_slice *partial_equiv_set (tree) { return NULL; }
126 : : void valid_equivs (bitmap b, const_bitmap equivs, basic_block bb);
127 : : // Query for a relation between two equivalency sets in a basic block.
128 : 0 : virtual relation_kind query (basic_block, const_bitmap, const_bitmap)
129 : 0 : { return VREL_VARYING; }
130 : : friend class path_oracle;
131 : : };
132 : :
133 : : // Instance with no storage used for default queries with no active oracle.
134 : : extern relation_oracle default_relation_oracle;
135 : :
136 : : // This class represents an equivalency set, and contains a link to the next
137 : : // one in the list to be searched.
138 : :
139 : : class equiv_chain
140 : : {
141 : : public:
142 : : bitmap m_names; // ssa-names in equiv set.
143 : : basic_block m_bb; // Block this belongs to
144 : : equiv_chain *m_next; // Next in block list.
145 : : void dump (FILE *f) const; // Show names in this list.
146 : : equiv_chain *find (unsigned ssa);
147 : : };
148 : :
149 : : class pe_slice
150 : : {
151 : : public:
152 : : tree ssa_base; // Slice of this name.
153 : : relation_kind code; // bits that are equivalent.
154 : : bitmap members; // Other members in the partial equivalency.
155 : : };
156 : :
157 : : // The equivalency oracle maintains equivalencies using the dominator tree.
158 : : // Equivalencies apply to an entire basic block. Equivalencies on edges
159 : : // can be represented only on edges whose destination is a single-pred block,
160 : : // and the equivalence is simply applied to that successor block.
161 : :
162 : : class equiv_oracle : public relation_oracle
163 : : {
164 : : public:
165 : : equiv_oracle ();
166 : : ~equiv_oracle ();
167 : :
168 : : const_bitmap equiv_set (tree ssa, basic_block bb) final override;
169 : : void record (basic_block bb, relation_kind k, tree ssa1, tree ssa2) override;
170 : :
171 : : relation_kind partial_equiv (tree ssa1, tree ssa2, tree *base = NULL) const;
172 : : relation_kind query (basic_block, tree, tree) override;
173 : : relation_kind query (basic_block, const_bitmap, const_bitmap) override;
174 : : void dump (FILE *f, basic_block bb) const override;
175 : : void dump (FILE *f) const override;
176 : :
177 : : protected:
178 : : void add_partial_equiv (relation_kind, tree, tree);
179 : : const pe_slice *partial_equiv_set (tree name) final override;
180 : 47765472 : inline bool has_equiv_p (unsigned v) { return bitmap_bit_p (m_equiv_set, v); }
181 : : bitmap_obstack m_bitmaps;
182 : : struct obstack m_chain_obstack;
183 : : private:
184 : : bitmap m_equiv_set; // Index by ssa-name. true if an equivalence exists.
185 : : vec <equiv_chain *> m_equiv; // Index by BB. list of equivalences.
186 : : vec <bitmap> m_self_equiv; // Index by ssa-name, self equivalency set.
187 : : vec <pe_slice> m_partial; // Partial equivalencies.
188 : :
189 : : void limit_check (basic_block bb = NULL);
190 : : equiv_chain *find_equiv_block (unsigned ssa, int bb) const;
191 : : equiv_chain *find_equiv_dom (tree name, basic_block bb) const;
192 : :
193 : : bitmap register_equiv (basic_block bb, unsigned v, equiv_chain *equiv_1);
194 : : bitmap register_equiv (basic_block bb, equiv_chain *equiv_1,
195 : : equiv_chain *equiv_2);
196 : : void register_initial_def (tree ssa);
197 : : void add_equiv_to_block (basic_block bb, bitmap equiv);
198 : : };
199 : :
200 : : // Summary block header for relations.
201 : :
202 : : class relation_chain_head
203 : : {
204 : : public:
205 : : bitmap m_names; // ssa_names with relations in this block.
206 : : class relation_chain *m_head; // List of relations in block.
207 : : int m_num_relations; // Number of relations in block.
208 : : relation_kind find_relation (const_bitmap b1, const_bitmap b2) const;
209 : : };
210 : :
211 : : // A relation oracle maintains a set of relations between ssa_names using the
212 : : // dominator tree structures. Equivalencies are considered a subset of
213 : : // a general relation and maintained by an equivalence oracle by transparently
214 : : // passing any EQ_EXPR relations to it.
215 : : // Relations are handled at the basic block level. All relations apply to
216 : : // an entire block, and are thus kept in a summary index by block.
217 : : // Similar to the equivalence oracle, edges are handled by applying the
218 : : // relation to the destination block of the edge, but ONLY if that block
219 : : // has a single successor. For now.
220 : :
221 : : class dom_oracle : public equiv_oracle
222 : : {
223 : : public:
224 : : dom_oracle (bool do_trans_p = true);
225 : : ~dom_oracle ();
226 : :
227 : : void record (basic_block bb, relation_kind k, tree op1, tree op2)
228 : : final override;
229 : :
230 : : relation_kind query (basic_block bb, tree ssa1, tree ssa2) final override;
231 : : relation_kind query (basic_block bb, const_bitmap b1, const_bitmap b2)
232 : : final override;
233 : :
234 : : void dump (FILE *f, basic_block bb) const final override;
235 : : void dump (FILE *f) const final override;
236 : : protected:
237 : : virtual relation_chain *next_relation (basic_block, relation_chain *,
238 : : tree) const;
239 : : bool m_do_trans_p;
240 : : bitmap m_tmp, m_tmp2;
241 : : bitmap m_relation_set; // Index by ssa-name. True if a relation exists
242 : : vec <relation_chain_head> m_relations; // Index by BB, list of relations.
243 : : relation_kind find_relation_block (unsigned bb, const_bitmap b1,
244 : : const_bitmap b2) const;
245 : : relation_kind find_relation_block (int bb, unsigned v1, unsigned v2,
246 : : relation_chain **obj = NULL) const;
247 : : relation_kind find_relation_dom (basic_block bb, unsigned v1, unsigned v2) const;
248 : : relation_chain *set_one_relation (basic_block bb, relation_kind k, tree op1,
249 : : tree op2);
250 : : void register_transitives (basic_block, const class value_relation &);
251 : :
252 : : };
253 : :
254 : : // A path_oracle implements relations in a list. The only sense of ordering
255 : : // is the latest registered relation is the first found during a search.
256 : : // It can be constructed with an optional "root" oracle which will be used
257 : : // to look up any relations not found in the list.
258 : : // This allows the client to walk paths starting at some block and register
259 : : // and query relations along that path, ignoring other edges.
260 : : //
261 : : // For registering a relation, a query if made of the root oracle if there is
262 : : // any known relationship at block BB, and it is combined with this new
263 : : // relation and entered in the list.
264 : : //
265 : : // Queries are resolved by looking first in the list, and only if nothing is
266 : : // found is the root oracle queried at block BB.
267 : : //
268 : : // reset_path is used to clear all locally registered paths to initial state.
269 : :
270 : : class path_oracle : public relation_oracle
271 : : {
272 : : public:
273 : : path_oracle (relation_oracle *oracle = NULL);
274 : : ~path_oracle ();
275 : : const_bitmap equiv_set (tree, basic_block) final override;
276 : : void record (basic_block, relation_kind, tree, tree) final override;
277 : : void killing_def (tree);
278 : : relation_kind query (basic_block, tree, tree) final override;
279 : : relation_kind query (basic_block, const_bitmap, const_bitmap) final override;
280 : : void reset_path (relation_oracle *oracle = NULL);
281 : 51315625 : void set_root_oracle (relation_oracle *oracle) { m_root = oracle; }
282 : : void dump (FILE *, basic_block) const final override;
283 : : void dump (FILE *) const final override;
284 : : private:
285 : : void register_equiv (basic_block bb, tree ssa1, tree ssa2);
286 : : equiv_chain m_equiv;
287 : : relation_chain_head m_relations;
288 : : relation_oracle *m_root;
289 : : bitmap m_killed_defs;
290 : :
291 : : bitmap_obstack m_bitmaps;
292 : : struct obstack m_chain_obstack;
293 : : };
294 : :
295 : : // Used to assist with iterating over the equivalence list.
296 : : class equiv_relation_iterator {
297 : : public:
298 : : equiv_relation_iterator (relation_oracle *oracle, basic_block bb, tree name,
299 : : bool full = true, bool partial = false);
300 : : void next ();
301 : : tree get_name (relation_kind *rel = NULL);
302 : : protected:
303 : : relation_oracle *m_oracle;
304 : : const_bitmap m_bm;
305 : : const pe_slice *m_pe;
306 : : bitmap_iterator m_bi;
307 : : unsigned m_y;
308 : : tree m_name;
309 : : };
310 : :
311 : : #define FOR_EACH_EQUIVALENCE(oracle, bb, name, equiv_name) \
312 : : for (equiv_relation_iterator iter (oracle, bb, name, true, false); \
313 : : ((equiv_name) = iter.get_name ()); \
314 : : iter.next ())
315 : :
316 : : #define FOR_EACH_PARTIAL_EQUIV(oracle, bb, name, equiv_name, equiv_rel) \
317 : : for (equiv_relation_iterator iter (oracle, bb, name, false, true); \
318 : : ((equiv_name) = iter.get_name (&equiv_rel)); \
319 : : iter.next ())
320 : :
321 : : #define FOR_EACH_PARTIAL_AND_FULL_EQUIV(oracle, bb, name, equiv_name, \
322 : : equiv_rel) \
323 : : for (equiv_relation_iterator iter (oracle, bb, name, true, true); \
324 : : ((equiv_name) = iter.get_name (&equiv_rel)); \
325 : : iter.next ())
326 : :
327 : : // -----------------------------------------------------------------------
328 : :
329 : : // Range-ops deals with a LHS and 2 operands. A relation trio is a set of
330 : : // 3 potential relations packed into a single unsigned value.
331 : : // 1 - LHS relation OP1
332 : : // 2 - LHS relation OP2
333 : : // 3 - OP1 relation OP2
334 : : // VREL_VARYING is a value of 0, and is the default for each position.
335 : : class relation_trio
336 : : {
337 : : public:
338 : : relation_trio ();
339 : : relation_trio (relation_kind lhs_op1, relation_kind lhs_op2,
340 : : relation_kind op1_op2);
341 : : relation_kind lhs_op1 ();
342 : : relation_kind lhs_op2 ();
343 : : relation_kind op1_op2 ();
344 : : relation_trio swap_op1_op2 ();
345 : :
346 : : static relation_trio lhs_op1 (relation_kind k);
347 : : static relation_trio lhs_op2 (relation_kind k);
348 : : static relation_trio op1_op2 (relation_kind k);
349 : :
350 : : protected:
351 : : unsigned m_val;
352 : : };
353 : :
354 : : // Default VREL_VARYING for all 3 relations.
355 : : #define TRIO_VARYING relation_trio ()
356 : :
357 : : #define TRIO_SHIFT 4
358 : : #define TRIO_MASK 0x000F
359 : :
360 : : // These 3 classes are shortcuts for when a caller has a single relation to
361 : : // pass as a trio, it can simply construct the appropriate one. The other
362 : : // unspecified relations will be VREL_VARYING.
363 : :
364 : 229365398 : inline relation_trio::relation_trio ()
365 : : {
366 : 229365398 : STATIC_ASSERT (VREL_LAST <= (1 << TRIO_SHIFT));
367 : 229365398 : m_val = 0;
368 : : }
369 : :
370 : 220738112 : inline relation_trio::relation_trio (relation_kind lhs_op1,
371 : : relation_kind lhs_op2,
372 : : relation_kind op1_op2)
373 : : {
374 : 220738112 : STATIC_ASSERT (VREL_LAST <= (1 << TRIO_SHIFT));
375 : 220738112 : unsigned i1 = (unsigned) lhs_op1;
376 : 220738112 : unsigned i2 = ((unsigned) lhs_op2) << TRIO_SHIFT;
377 : 220738112 : unsigned i3 = ((unsigned) op1_op2) << (TRIO_SHIFT * 2);
378 : 220738112 : m_val = i1 | i2 | i3;
379 : : }
380 : :
381 : : inline relation_trio
382 : 602519 : relation_trio::lhs_op1 (relation_kind k)
383 : : {
384 : 602519 : return relation_trio (k, VREL_VARYING, VREL_VARYING);
385 : : }
386 : : inline relation_trio
387 : 567155 : relation_trio::lhs_op2 (relation_kind k)
388 : : {
389 : 567155 : return relation_trio (VREL_VARYING, k, VREL_VARYING);
390 : : }
391 : : inline relation_trio
392 : 163035753 : relation_trio::op1_op2 (relation_kind k)
393 : : {
394 : 163035753 : return relation_trio (VREL_VARYING, VREL_VARYING, k);
395 : : }
396 : :
397 : : inline relation_kind
398 : 17913213 : relation_trio::lhs_op1 ()
399 : : {
400 : 9359352 : return (relation_kind) (m_val & TRIO_MASK);
401 : : }
402 : :
403 : : inline relation_kind
404 : 8777912 : relation_trio::lhs_op2 ()
405 : : {
406 : 8889744 : return (relation_kind) ((m_val >> TRIO_SHIFT) & TRIO_MASK);
407 : : }
408 : :
409 : : inline relation_kind
410 : 290610555 : relation_trio::op1_op2 ()
411 : : {
412 : 281832964 : return (relation_kind) ((m_val >> (TRIO_SHIFT * 2)) & TRIO_MASK);
413 : : }
414 : :
415 : : inline relation_trio
416 : 8777591 : relation_trio::swap_op1_op2 ()
417 : : {
418 : 8777591 : return relation_trio (lhs_op2 (), lhs_op1 (), relation_swap (op1_op2 ()));
419 : : }
420 : :
421 : : // -----------------------------------------------------------------------
422 : :
423 : : // The value-relation class is used to encapsulate the representation of an
424 : : // individual relation between 2 ssa-names, and to facilitate operating on
425 : : // the relation.
426 : :
427 : : class value_relation
428 : : {
429 : : public:
430 : : value_relation ();
431 : : value_relation (relation_kind kind, tree n1, tree n2);
432 : : void set_relation (relation_kind kind, tree n1, tree n2);
433 : :
434 : 31196875 : inline relation_kind kind () const { return related; }
435 : 144203793 : inline tree op1 () const { return name1; }
436 : 141906249 : inline tree op2 () const { return name2; }
437 : :
438 : : relation_trio create_trio (tree lhs, tree op1, tree op2);
439 : : bool union_ (value_relation &p);
440 : : bool intersect (value_relation &p);
441 : : void swap ();
442 : : bool apply_transitive (const value_relation &rel);
443 : :
444 : : void dump (FILE *f) const;
445 : : private:
446 : : relation_kind related;
447 : : tree name1, name2;
448 : : };
449 : :
450 : : // Set relation R between ssa_name N1 and N2.
451 : :
452 : : inline void
453 : 111896069 : value_relation::set_relation (relation_kind r, tree n1, tree n2)
454 : : {
455 : 111896069 : gcc_checking_assert (TREE_CODE (n1) == SSA_NAME
456 : : && TREE_CODE (n2) == SSA_NAME);
457 : 111896069 : related = r;
458 : 111896069 : name1 = n1;
459 : 111896069 : name2 = n2;
460 : 111896069 : }
461 : :
462 : : // Default constructor.
463 : :
464 : : inline
465 : 111884127 : value_relation::value_relation ()
466 : : {
467 : 111884127 : related = VREL_VARYING;
468 : 111884127 : name1 = NULL_TREE;
469 : 111884127 : name2 = NULL_TREE;
470 : : }
471 : :
472 : : // Constructor for relation R between SSA version N1 and N2.
473 : :
474 : : inline
475 : 37488426 : value_relation::value_relation (relation_kind kind, tree n1, tree n2)
476 : : {
477 : 37488426 : set_relation (kind, n1, n2);
478 : : }
479 : :
480 : :
481 : : class block_relation_iterator {
482 : : public:
483 : : block_relation_iterator (const relation_oracle *oracle, basic_block bb,
484 : : value_relation &, tree name = NULL);
485 : : void get_next_relation (value_relation &vr);
486 : : const relation_oracle *m_oracle;
487 : : basic_block m_bb;
488 : : relation_chain *m_ptr;
489 : : bool m_done;
490 : : tree m_name;
491 : : };
492 : :
493 : : #define FOR_EACH_RELATION_BB(oracle, bb, vr) \
494 : : for (block_relation_iterator iter (oracle, bb, vr); \
495 : : !iter.m_done; \
496 : : iter.get_next_relation (vr))
497 : :
498 : : #define FOR_EACH_RELATION_NAME(oracle, bb, name, vr) \
499 : : for (block_relation_iterator iter (oracle, bb, vr, name); \
500 : : !iter.m_done; \
501 : : iter.get_next_relation (vr))
502 : :
503 : :
504 : : // Return the number of bits associated with partial equivalency T.
505 : : // Return 0 if this is not a supported partial equivalency relation.
506 : :
507 : : inline int
508 : 17007598 : pe_to_bits (relation_kind t)
509 : : {
510 : 17007598 : switch (t)
511 : : {
512 : : case VREL_PE8:
513 : : return 8;
514 : : case VREL_PE16:
515 : : return 16;
516 : : case VREL_PE32:
517 : : return 32;
518 : : case VREL_PE64:
519 : : return 64;
520 : : default:
521 : : return 0;
522 : : }
523 : : }
524 : :
525 : : // Return the partial equivalency code associated with the number of BITS.
526 : : // return VREL_VARYING if there is no exact match.
527 : :
528 : : inline relation_kind
529 : 35685951 : bits_to_pe (int bits)
530 : : {
531 : 35685951 : switch (bits)
532 : : {
533 : : case 8:
534 : : return VREL_PE8;
535 : : case 16:
536 : : return VREL_PE16;
537 : : case 32:
538 : : return VREL_PE32;
539 : : case 64:
540 : : return VREL_PE64;
541 : : default:
542 : : return VREL_VARYING;
543 : : }
544 : : }
545 : :
546 : : // Given partial equivalencies T1 and T2, return the smallest kind.
547 : :
548 : : inline relation_kind
549 : 7901137 : pe_min (relation_kind t1, relation_kind t2)
550 : : {
551 : 7901137 : gcc_checking_assert (relation_partial_equiv_p (t1));
552 : 7901137 : gcc_checking_assert (relation_partial_equiv_p (t2));
553 : : // VREL_PE are declared small to large, so simple min will suffice.
554 : 7901137 : return MIN (t1, t2);
555 : : }
556 : : #endif /* GCC_VALUE_RELATION_H */
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