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1 : : /* Straight-line strength reduction.
2 : : Copyright (C) 2012-2024 Free Software Foundation, Inc.
3 : : Contributed by Bill Schmidt, IBM <wschmidt@linux.ibm.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 : : /* There are many algorithms for performing strength reduction on
22 : : loops. This is not one of them. IVOPTS handles strength reduction
23 : : of induction variables just fine. This pass is intended to pick
24 : : up the crumbs it leaves behind, by considering opportunities for
25 : : strength reduction along dominator paths.
26 : :
27 : : Strength reduction addresses explicit multiplies, and certain
28 : : multiplies implicit in addressing expressions. It would also be
29 : : possible to apply strength reduction to divisions and modulos,
30 : : but such opportunities are relatively uncommon.
31 : :
32 : : Strength reduction is also currently restricted to integer operations.
33 : : If desired, it could be extended to floating-point operations under
34 : : control of something like -funsafe-math-optimizations. */
35 : :
36 : : #include "config.h"
37 : : #include "system.h"
38 : : #include "coretypes.h"
39 : : #include "backend.h"
40 : : #include "rtl.h"
41 : : #include "tree.h"
42 : : #include "gimple.h"
43 : : #include "cfghooks.h"
44 : : #include "tree-pass.h"
45 : : #include "ssa.h"
46 : : #include "expmed.h"
47 : : #include "gimple-pretty-print.h"
48 : : #include "fold-const.h"
49 : : #include "gimple-iterator.h"
50 : : #include "gimplify-me.h"
51 : : #include "stor-layout.h"
52 : : #include "cfgloop.h"
53 : : #include "tree-cfg.h"
54 : : #include "domwalk.h"
55 : : #include "tree-ssa-address.h"
56 : : #include "tree-affine.h"
57 : : #include "tree-eh.h"
58 : : #include "builtins.h"
59 : : #include "tree-ssa-dce.h"
60 : :
61 : : /* Information about a strength reduction candidate. Each statement
62 : : in the candidate table represents an expression of one of the
63 : : following forms (the special case of CAND_REF will be described
64 : : later):
65 : :
66 : : (CAND_MULT) S1: X = (B + i) * S
67 : : (CAND_ADD) S1: X = B + (i * S)
68 : :
69 : : Here X and B are SSA names, i is an integer constant, and S is
70 : : either an SSA name or a constant. We call B the "base," i the
71 : : "index", and S the "stride."
72 : :
73 : : Any statement S0 that dominates S1 and is of the form:
74 : :
75 : : (CAND_MULT) S0: Y = (B + i') * S
76 : : (CAND_ADD) S0: Y = B + (i' * S)
77 : :
78 : : is called a "basis" for S1. In both cases, S1 may be replaced by
79 : :
80 : : S1': X = Y + (i - i') * S,
81 : :
82 : : where (i - i') * S is folded to the extent possible.
83 : :
84 : : All gimple statements are visited in dominator order, and each
85 : : statement that may contribute to one of the forms of S1 above is
86 : : given at least one entry in the candidate table. Such statements
87 : : include addition, pointer addition, subtraction, multiplication,
88 : : negation, copies, and nontrivial type casts. If a statement may
89 : : represent more than one expression of the forms of S1 above,
90 : : multiple "interpretations" are stored in the table and chained
91 : : together. Examples:
92 : :
93 : : * An add of two SSA names may treat either operand as the base.
94 : : * A multiply of two SSA names, likewise.
95 : : * A copy or cast may be thought of as either a CAND_MULT with
96 : : i = 0 and S = 1, or as a CAND_ADD with i = 0 or S = 0.
97 : :
98 : : Candidate records are allocated from an obstack. They are addressed
99 : : both from a hash table keyed on S1, and from a vector of candidate
100 : : pointers arranged in predominator order.
101 : :
102 : : Opportunity note
103 : : ----------------
104 : : Currently we don't recognize:
105 : :
106 : : S0: Y = (S * i') - B
107 : : S1: X = (S * i) - B
108 : :
109 : : as a strength reduction opportunity, even though this S1 would
110 : : also be replaceable by the S1' above. This can be added if it
111 : : comes up in practice.
112 : :
113 : : Strength reduction in addressing
114 : : --------------------------------
115 : : There is another kind of candidate known as CAND_REF. A CAND_REF
116 : : describes a statement containing a memory reference having
117 : : complex addressing that might benefit from strength reduction.
118 : : Specifically, we are interested in references for which
119 : : get_inner_reference returns a base address, offset, and bitpos as
120 : : follows:
121 : :
122 : : base: MEM_REF (T1, C1)
123 : : offset: MULT_EXPR (PLUS_EXPR (T2, C2), C3)
124 : : bitpos: C4 * BITS_PER_UNIT
125 : :
126 : : Here T1 and T2 are arbitrary trees, and C1, C2, C3, C4 are
127 : : arbitrary integer constants. Note that C2 may be zero, in which
128 : : case the offset will be MULT_EXPR (T2, C3).
129 : :
130 : : When this pattern is recognized, the original memory reference
131 : : can be replaced with:
132 : :
133 : : MEM_REF (POINTER_PLUS_EXPR (T1, MULT_EXPR (T2, C3)),
134 : : C1 + (C2 * C3) + C4)
135 : :
136 : : which distributes the multiply to allow constant folding. When
137 : : two or more addressing expressions can be represented by MEM_REFs
138 : : of this form, differing only in the constants C1, C2, and C4,
139 : : making this substitution produces more efficient addressing during
140 : : the RTL phases. When there are not at least two expressions with
141 : : the same values of T1, T2, and C3, there is nothing to be gained
142 : : by the replacement.
143 : :
144 : : Strength reduction of CAND_REFs uses the same infrastructure as
145 : : that used by CAND_MULTs and CAND_ADDs. We record T1 in the base (B)
146 : : field, MULT_EXPR (T2, C3) in the stride (S) field, and
147 : : C1 + (C2 * C3) + C4 in the index (i) field. A basis for a CAND_REF
148 : : is thus another CAND_REF with the same B and S values. When at
149 : : least two CAND_REFs are chained together using the basis relation,
150 : : each of them is replaced as above, resulting in improved code
151 : : generation for addressing.
152 : :
153 : : Conditional candidates
154 : : ======================
155 : :
156 : : Conditional candidates are best illustrated with an example.
157 : : Consider the code sequence:
158 : :
159 : : (1) x_0 = ...;
160 : : (2) a_0 = x_0 * 5; MULT (B: x_0; i: 0; S: 5)
161 : : if (...)
162 : : (3) x_1 = x_0 + 1; ADD (B: x_0, i: 1; S: 1)
163 : : (4) x_2 = PHI <x_0, x_1>; PHI (B: x_0, i: 0, S: 1)
164 : : (5) x_3 = x_2 + 1; ADD (B: x_2, i: 1, S: 1)
165 : : (6) a_1 = x_3 * 5; MULT (B: x_2, i: 1; S: 5)
166 : :
167 : : Here strength reduction is complicated by the uncertain value of x_2.
168 : : A legitimate transformation is:
169 : :
170 : : (1) x_0 = ...;
171 : : (2) a_0 = x_0 * 5;
172 : : if (...)
173 : : {
174 : : (3) [x_1 = x_0 + 1;]
175 : : (3a) t_1 = a_0 + 5;
176 : : }
177 : : (4) [x_2 = PHI <x_0, x_1>;]
178 : : (4a) t_2 = PHI <a_0, t_1>;
179 : : (5) [x_3 = x_2 + 1;]
180 : : (6r) a_1 = t_2 + 5;
181 : :
182 : : where the bracketed instructions may go dead.
183 : :
184 : : To recognize this opportunity, we have to observe that statement (6)
185 : : has a "hidden basis" (2). The hidden basis is unlike a normal basis
186 : : in that the statement and the hidden basis have different base SSA
187 : : names (x_2 and x_0, respectively). The relationship is established
188 : : when a statement's base name (x_2) is defined by a phi statement (4),
189 : : each argument of which (x_0, x_1) has an identical "derived base name."
190 : : If the argument is defined by a candidate (as x_1 is by (3)) that is a
191 : : CAND_ADD having a stride of 1, the derived base name of the argument is
192 : : the base name of the candidate (x_0). Otherwise, the argument itself
193 : : is its derived base name (as is the case with argument x_0).
194 : :
195 : : The hidden basis for statement (6) is the nearest dominating candidate
196 : : whose base name is the derived base name (x_0) of the feeding phi (4),
197 : : and whose stride is identical to that of the statement. We can then
198 : : create the new "phi basis" (4a) and feeding adds along incoming arcs (3a),
199 : : allowing the final replacement of (6) by the strength-reduced (6r).
200 : :
201 : : To facilitate this, a new kind of candidate (CAND_PHI) is introduced.
202 : : A CAND_PHI is not a candidate for replacement, but is maintained in the
203 : : candidate table to ease discovery of hidden bases. Any phi statement
204 : : whose arguments share a common derived base name is entered into the
205 : : table with the derived base name, an (arbitrary) index of zero, and a
206 : : stride of 1. A statement with a hidden basis can then be detected by
207 : : simply looking up its feeding phi definition in the candidate table,
208 : : extracting the derived base name, and searching for a basis in the
209 : : usual manner after substituting the derived base name.
210 : :
211 : : Note that the transformation is only valid when the original phi and
212 : : the statements that define the phi's arguments are all at the same
213 : : position in the loop hierarchy. */
214 : :
215 : :
216 : : /* Index into the candidate vector, offset by 1. VECs are zero-based,
217 : : while cand_idx's are one-based, with zero indicating null. */
218 : : typedef unsigned cand_idx;
219 : :
220 : : /* The kind of candidate. */
221 : : enum cand_kind
222 : : {
223 : : CAND_MULT,
224 : : CAND_ADD,
225 : : CAND_REF,
226 : : CAND_PHI
227 : : };
228 : :
229 : : class slsr_cand_d
230 : : {
231 : : public:
232 : : /* The candidate statement S1. */
233 : : gimple *cand_stmt;
234 : :
235 : : /* The base expression B: often an SSA name, but not always. */
236 : : tree base_expr;
237 : :
238 : : /* The stride S. */
239 : : tree stride;
240 : :
241 : : /* The index constant i. */
242 : : offset_int index;
243 : :
244 : : /* The type of the candidate. This is normally the type of base_expr,
245 : : but casts may have occurred when combining feeding instructions.
246 : : A candidate can only be a basis for candidates of the same final type.
247 : : (For CAND_REFs, this is the type to be used for operand 1 of the
248 : : replacement MEM_REF.) */
249 : : tree cand_type;
250 : :
251 : : /* The type to be used to interpret the stride field when the stride
252 : : is not a constant. Normally the same as the type of the recorded
253 : : stride, but when the stride has been cast we need to maintain that
254 : : knowledge in order to make legal substitutions without losing
255 : : precision. When the stride is a constant, this will be sizetype. */
256 : : tree stride_type;
257 : :
258 : : /* The kind of candidate (CAND_MULT, etc.). */
259 : : enum cand_kind kind;
260 : :
261 : : /* Index of this candidate in the candidate vector. */
262 : : cand_idx cand_num;
263 : :
264 : : /* Index of the next candidate record for the same statement.
265 : : A statement may be useful in more than one way (e.g., due to
266 : : commutativity). So we can have multiple "interpretations"
267 : : of a statement. */
268 : : cand_idx next_interp;
269 : :
270 : : /* Index of the first candidate record in a chain for the same
271 : : statement. */
272 : : cand_idx first_interp;
273 : :
274 : : /* Index of the basis statement S0, if any, in the candidate vector. */
275 : : cand_idx basis;
276 : :
277 : : /* First candidate for which this candidate is a basis, if one exists. */
278 : : cand_idx dependent;
279 : :
280 : : /* Next candidate having the same basis as this one. */
281 : : cand_idx sibling;
282 : :
283 : : /* If this is a conditional candidate, the CAND_PHI candidate
284 : : that defines the base SSA name B. */
285 : : cand_idx def_phi;
286 : :
287 : : /* Savings that can be expected from eliminating dead code if this
288 : : candidate is replaced. */
289 : : int dead_savings;
290 : :
291 : : /* For PHI candidates, use a visited flag to keep from processing the
292 : : same PHI twice from multiple paths. */
293 : : int visited;
294 : :
295 : : /* We sometimes have to cache a phi basis with a phi candidate to
296 : : avoid processing it twice. Valid only if visited==1. */
297 : : tree cached_basis;
298 : : };
299 : :
300 : : typedef class slsr_cand_d slsr_cand, *slsr_cand_t;
301 : : typedef const class slsr_cand_d *const_slsr_cand_t;
302 : :
303 : : /* Pointers to candidates are chained together as part of a mapping
304 : : from base expressions to the candidates that use them. */
305 : :
306 : : struct cand_chain_d
307 : : {
308 : : /* Base expression for the chain of candidates: often, but not
309 : : always, an SSA name. */
310 : : tree base_expr;
311 : :
312 : : /* Pointer to a candidate. */
313 : : slsr_cand_t cand;
314 : :
315 : : /* Chain pointer. */
316 : : struct cand_chain_d *next;
317 : :
318 : : };
319 : :
320 : : typedef struct cand_chain_d cand_chain, *cand_chain_t;
321 : : typedef const struct cand_chain_d *const_cand_chain_t;
322 : :
323 : : /* Information about a unique "increment" associated with candidates
324 : : having an SSA name for a stride. An increment is the difference
325 : : between the index of the candidate and the index of its basis,
326 : : i.e., (i - i') as discussed in the module commentary.
327 : :
328 : : When we are not going to generate address arithmetic we treat
329 : : increments that differ only in sign as the same, allowing sharing
330 : : of the cost of initializers. The absolute value of the increment
331 : : is stored in the incr_info. */
332 : :
333 : : class incr_info_d
334 : : {
335 : : public:
336 : : /* The increment that relates a candidate to its basis. */
337 : : offset_int incr;
338 : :
339 : : /* How many times the increment occurs in the candidate tree. */
340 : : unsigned count;
341 : :
342 : : /* Cost of replacing candidates using this increment. Negative and
343 : : zero costs indicate replacement should be performed. */
344 : : int cost;
345 : :
346 : : /* If this increment is profitable but is not -1, 0, or 1, it requires
347 : : an initializer T_0 = stride * incr to be found or introduced in the
348 : : nearest common dominator of all candidates. This field holds T_0
349 : : for subsequent use. */
350 : : tree initializer;
351 : :
352 : : /* If the initializer was found to already exist, this is the block
353 : : where it was found. */
354 : : basic_block init_bb;
355 : : };
356 : :
357 : : typedef class incr_info_d incr_info, *incr_info_t;
358 : :
359 : : /* Candidates are maintained in a vector. If candidate X dominates
360 : : candidate Y, then X appears before Y in the vector; but the
361 : : converse does not necessarily hold. */
362 : : static vec<slsr_cand_t> cand_vec;
363 : :
364 : : enum cost_consts
365 : : {
366 : : COST_NEUTRAL = 0,
367 : : COST_INFINITE = 1000
368 : : };
369 : :
370 : : enum stride_status
371 : : {
372 : : UNKNOWN_STRIDE = 0,
373 : : KNOWN_STRIDE = 1
374 : : };
375 : :
376 : : enum phi_adjust_status
377 : : {
378 : : NOT_PHI_ADJUST = 0,
379 : : PHI_ADJUST = 1
380 : : };
381 : :
382 : : enum count_phis_status
383 : : {
384 : : DONT_COUNT_PHIS = 0,
385 : : COUNT_PHIS = 1
386 : : };
387 : :
388 : : /* Constrain how many PHI nodes we will visit for a conditional
389 : : candidate (depth and breadth). */
390 : : const int MAX_SPREAD = 16;
391 : :
392 : : /* Pointer map embodying a mapping from statements to candidates. */
393 : : static hash_map<gimple *, slsr_cand_t> *stmt_cand_map;
394 : :
395 : : /* Obstack for candidates. */
396 : : static struct obstack cand_obstack;
397 : :
398 : : /* Obstack for candidate chains. */
399 : : static struct obstack chain_obstack;
400 : :
401 : : /* An array INCR_VEC of incr_infos is used during analysis of related
402 : : candidates having an SSA name for a stride. INCR_VEC_LEN describes
403 : : its current length. MAX_INCR_VEC_LEN is used to avoid costly
404 : : pathological cases. */
405 : : static incr_info_t incr_vec;
406 : : static unsigned incr_vec_len;
407 : : const int MAX_INCR_VEC_LEN = 16;
408 : :
409 : : /* For a chain of candidates with unknown stride, indicates whether or not
410 : : we must generate pointer arithmetic when replacing statements. */
411 : : static bool address_arithmetic_p;
412 : :
413 : : /* Forward function declarations. */
414 : : static slsr_cand_t base_cand_from_table (tree);
415 : : static tree introduce_cast_before_cand (slsr_cand_t, tree, tree);
416 : : static bool legal_cast_p_1 (tree, tree);
417 : :
418 : : /* Produce a pointer to the IDX'th candidate in the candidate vector. */
419 : :
420 : : static slsr_cand_t
421 : 7014436 : lookup_cand (cand_idx idx)
422 : : {
423 : 0 : return cand_vec[idx];
424 : : }
425 : :
426 : : /* Helper for hashing a candidate chain header. */
427 : :
428 : : struct cand_chain_hasher : nofree_ptr_hash <cand_chain>
429 : : {
430 : : static inline hashval_t hash (const cand_chain *);
431 : : static inline bool equal (const cand_chain *, const cand_chain *);
432 : : };
433 : :
434 : : inline hashval_t
435 : 29262668 : cand_chain_hasher::hash (const cand_chain *p)
436 : : {
437 : 29262668 : tree base_expr = p->base_expr;
438 : 29262668 : return iterative_hash_expr (base_expr, 0);
439 : : }
440 : :
441 : : inline bool
442 : 23897191 : cand_chain_hasher::equal (const cand_chain *chain1, const cand_chain *chain2)
443 : : {
444 : 23897191 : return operand_equal_p (chain1->base_expr, chain2->base_expr, 0);
445 : : }
446 : :
447 : : /* Hash table embodying a mapping from base exprs to chains of candidates. */
448 : : static hash_table<cand_chain_hasher> *base_cand_map;
449 : :
450 : : /* Pointer map used by tree_to_aff_combination_expand. */
451 : : static hash_map<tree, name_expansion *> *name_expansions;
452 : : /* Pointer map embodying a mapping from bases to alternative bases. */
453 : : static hash_map<tree, tree> *alt_base_map;
454 : :
455 : : /* Given BASE, use the tree affine combiniation facilities to
456 : : find the underlying tree expression for BASE, with any
457 : : immediate offset excluded.
458 : :
459 : : N.B. we should eliminate this backtracking with better forward
460 : : analysis in a future release. */
461 : :
462 : : static tree
463 : 39782 : get_alternative_base (tree base)
464 : : {
465 : 39782 : tree *result = alt_base_map->get (base);
466 : :
467 : 39782 : if (result == NULL)
468 : : {
469 : 8631 : tree expr;
470 : 8631 : aff_tree aff;
471 : :
472 : 8631 : tree_to_aff_combination_expand (base, TREE_TYPE (base),
473 : : &aff, &name_expansions);
474 : 8631 : aff.offset = 0;
475 : 8631 : expr = aff_combination_to_tree (&aff);
476 : :
477 : 17125 : gcc_assert (!alt_base_map->put (base, base == expr ? NULL : expr));
478 : :
479 : 8631 : return expr == base ? NULL : expr;
480 : 8631 : }
481 : :
482 : 31151 : return *result;
483 : : }
484 : :
485 : : /* Look in the candidate table for a CAND_PHI that defines BASE and
486 : : return it if found; otherwise return NULL. */
487 : :
488 : : static cand_idx
489 : 2174242 : find_phi_def (tree base)
490 : : {
491 : 2174242 : slsr_cand_t c;
492 : :
493 : 2174242 : if (TREE_CODE (base) != SSA_NAME)
494 : : return 0;
495 : :
496 : 2174242 : c = base_cand_from_table (base);
497 : :
498 : 154867 : if (!c || c->kind != CAND_PHI
499 : 2174989 : || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_phi_result (c->cand_stmt)))
500 : : return 0;
501 : :
502 : 742 : return c->cand_num;
503 : : }
504 : :
505 : : /* Determine whether all uses of NAME are directly or indirectly
506 : : used by STMT. That is, we want to know whether if STMT goes
507 : : dead, the definition of NAME also goes dead. */
508 : : static bool
509 : 177994 : uses_consumed_by_stmt (tree name, gimple *stmt, unsigned recurse = 0)
510 : : {
511 : 177994 : gimple *use_stmt;
512 : 177994 : imm_use_iterator iter;
513 : 177994 : bool retval = true;
514 : :
515 : 349067 : FOR_EACH_IMM_USE_STMT (use_stmt, iter, name)
516 : : {
517 : 261399 : if (use_stmt == stmt || is_gimple_debug (use_stmt))
518 : 168983 : continue;
519 : :
520 : 92416 : if (!is_gimple_assign (use_stmt)
521 : 35001 : || !gimple_get_lhs (use_stmt)
522 : 35001 : || !is_gimple_reg (gimple_get_lhs (use_stmt))
523 : 26242 : || recurse >= 10
524 : 118651 : || !uses_consumed_by_stmt (gimple_get_lhs (use_stmt), stmt,
525 : : recurse + 1))
526 : : {
527 : : retval = false;
528 : : break;
529 : : }
530 : 177994 : }
531 : :
532 : 177994 : return retval;
533 : : }
534 : :
535 : : /* Helper routine for find_basis_for_candidate. May be called twice:
536 : : once for the candidate's base expr, and optionally again either for
537 : : the candidate's phi definition or for a CAND_REF's alternative base
538 : : expression. */
539 : :
540 : : static slsr_cand_t
541 : 6946522 : find_basis_for_base_expr (slsr_cand_t c, tree base_expr)
542 : : {
543 : 6946522 : cand_chain mapping_key;
544 : 6946522 : cand_chain_t chain;
545 : 6946522 : slsr_cand_t basis = NULL;
546 : :
547 : : // Limit potential of N^2 behavior for long candidate chains.
548 : 6946522 : int iters = 0;
549 : 6946522 : int max_iters = param_max_slsr_candidate_scan;
550 : :
551 : 6946522 : mapping_key.base_expr = base_expr;
552 : 6946522 : chain = base_cand_map->find (&mapping_key);
553 : :
554 : 29231281 : for (; chain && iters < max_iters; chain = chain->next, ++iters)
555 : : {
556 : 22284759 : slsr_cand_t one_basis = chain->cand;
557 : :
558 : 40801907 : if (one_basis->kind != c->kind
559 : 13208953 : || one_basis->cand_stmt == c->cand_stmt
560 : 13208234 : || !operand_equal_p (one_basis->stride, c->stride, 0)
561 : 6591848 : || !types_compatible_p (one_basis->cand_type, c->cand_type)
562 : 5369752 : || !types_compatible_p (one_basis->stride_type, c->stride_type)
563 : 27654499 : || !dominated_by_p (CDI_DOMINATORS,
564 : 5369740 : gimple_bb (c->cand_stmt),
565 : 5369740 : gimple_bb (one_basis->cand_stmt)))
566 : 18517148 : continue;
567 : :
568 : 3767611 : tree lhs = gimple_assign_lhs (one_basis->cand_stmt);
569 : 3767611 : if (lhs && TREE_CODE (lhs) == SSA_NAME
570 : 7520601 : && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
571 : 34 : continue;
572 : :
573 : 3767577 : if (!basis || basis->cand_num < one_basis->cand_num)
574 : 22284759 : basis = one_basis;
575 : : }
576 : :
577 : 6946522 : return basis;
578 : : }
579 : :
580 : : /* Use the base expr from candidate C to look for possible candidates
581 : : that can serve as a basis for C. Each potential basis must also
582 : : appear in a block that dominates the candidate statement and have
583 : : the same stride and type. If more than one possible basis exists,
584 : : the one with highest index in the vector is chosen; this will be
585 : : the most immediately dominating basis. */
586 : :
587 : : static int
588 : 6945642 : find_basis_for_candidate (slsr_cand_t c)
589 : : {
590 : 6945642 : slsr_cand_t basis = find_basis_for_base_expr (c, c->base_expr);
591 : :
592 : : /* If a candidate doesn't have a basis using its base expression,
593 : : it may have a basis hidden by one or more intervening phis. */
594 : 6945642 : if (!basis && c->def_phi)
595 : : {
596 : 708 : basic_block basis_bb, phi_bb;
597 : 708 : slsr_cand_t phi_cand = lookup_cand (c->def_phi);
598 : 708 : basis = find_basis_for_base_expr (c, phi_cand->base_expr);
599 : :
600 : 708 : if (basis)
601 : : {
602 : : /* A hidden basis must dominate the phi-definition of the
603 : : candidate's base name. */
604 : 82 : phi_bb = gimple_bb (phi_cand->cand_stmt);
605 : 82 : basis_bb = gimple_bb (basis->cand_stmt);
606 : :
607 : 82 : if (phi_bb == basis_bb
608 : 82 : || !dominated_by_p (CDI_DOMINATORS, phi_bb, basis_bb))
609 : : {
610 : 12 : basis = NULL;
611 : 12 : c->basis = 0;
612 : : }
613 : :
614 : : /* If we found a hidden basis, estimate additional dead-code
615 : : savings if the phi and its feeding statements can be removed. */
616 : 82 : tree feeding_var = gimple_phi_result (phi_cand->cand_stmt);
617 : 82 : if (basis && uses_consumed_by_stmt (feeding_var, c->cand_stmt))
618 : 33 : c->dead_savings += phi_cand->dead_savings;
619 : : }
620 : : }
621 : :
622 : 6945642 : if (flag_expensive_optimizations && !basis && c->kind == CAND_REF)
623 : : {
624 : 14895 : tree alt_base_expr = get_alternative_base (c->base_expr);
625 : 14895 : if (alt_base_expr)
626 : 172 : basis = find_basis_for_base_expr (c, alt_base_expr);
627 : : }
628 : :
629 : 5967895 : if (basis)
630 : : {
631 : 1074896 : c->sibling = basis->dependent;
632 : 1074896 : basis->dependent = c->cand_num;
633 : 1074896 : return basis->cand_num;
634 : : }
635 : :
636 : : return 0;
637 : : }
638 : :
639 : : /* Record a mapping from BASE to C, indicating that C may potentially serve
640 : : as a basis using that base expression. BASE may be the same as
641 : : C->BASE_EXPR; alternatively BASE can be a different tree that share the
642 : : underlining expression of C->BASE_EXPR. */
643 : :
644 : : static void
645 : 6957060 : record_potential_basis (slsr_cand_t c, tree base)
646 : : {
647 : 6957060 : cand_chain_t node;
648 : 6957060 : cand_chain **slot;
649 : :
650 : 6957060 : gcc_assert (base);
651 : :
652 : 6957060 : node = (cand_chain_t) obstack_alloc (&chain_obstack, sizeof (cand_chain));
653 : 6957060 : node->base_expr = base;
654 : 6957060 : node->cand = c;
655 : 6957060 : node->next = NULL;
656 : 6957060 : slot = base_cand_map->find_slot (node, INSERT);
657 : :
658 : 6957060 : if (*slot)
659 : : {
660 : 3396537 : cand_chain_t head = (cand_chain_t) (*slot);
661 : 3396537 : node->next = head->next;
662 : 3396537 : head->next = node;
663 : : }
664 : : else
665 : 3560523 : *slot = node;
666 : 6957060 : }
667 : :
668 : : /* Allocate storage for a new candidate and initialize its fields.
669 : : Attempt to find a basis for the candidate.
670 : :
671 : : For CAND_REF, an alternative base may also be recorded and used
672 : : to find a basis. This helps cases where the expression hidden
673 : : behind BASE (which is usually an SSA_NAME) has immediate offset,
674 : : e.g.
675 : :
676 : : a2[i][j] = 1;
677 : : a2[i + 20][j] = 2; */
678 : :
679 : : static slsr_cand_t
680 : 6956816 : alloc_cand_and_find_basis (enum cand_kind kind, gimple *gs, tree base,
681 : : const offset_int &index, tree stride, tree ctype,
682 : : tree stype, unsigned savings)
683 : : {
684 : 6956816 : slsr_cand_t c = (slsr_cand_t) obstack_alloc (&cand_obstack,
685 : : sizeof (slsr_cand));
686 : 6956816 : c->cand_stmt = gs;
687 : 6956816 : c->base_expr = base;
688 : 6956816 : c->stride = stride;
689 : 6956816 : c->index = index;
690 : 6956816 : c->cand_type = ctype;
691 : 6956816 : c->stride_type = stype;
692 : 6956816 : c->kind = kind;
693 : 6956816 : c->cand_num = cand_vec.length ();
694 : 6956816 : c->next_interp = 0;
695 : 6956816 : c->first_interp = c->cand_num;
696 : 6956816 : c->dependent = 0;
697 : 6956816 : c->sibling = 0;
698 : 6956816 : c->def_phi = kind == CAND_MULT ? find_phi_def (base) : 0;
699 : 6956816 : c->dead_savings = savings;
700 : 6956816 : c->visited = 0;
701 : 6956816 : c->cached_basis = NULL_TREE;
702 : :
703 : 6956816 : cand_vec.safe_push (c);
704 : :
705 : 6956816 : if (kind == CAND_PHI)
706 : 11174 : c->basis = 0;
707 : : else
708 : 6945642 : c->basis = find_basis_for_candidate (c);
709 : :
710 : 6956816 : record_potential_basis (c, base);
711 : 6956816 : if (flag_expensive_optimizations && kind == CAND_REF)
712 : : {
713 : 24887 : tree alt_base = get_alternative_base (base);
714 : 24887 : if (alt_base)
715 : 244 : record_potential_basis (c, alt_base);
716 : : }
717 : :
718 : 6956816 : return c;
719 : : }
720 : :
721 : : /* Determine the target cost of statement GS when compiling according
722 : : to SPEED. */
723 : :
724 : : static int
725 : 1204749 : stmt_cost (gimple *gs, bool speed)
726 : : {
727 : 1204749 : tree lhs, rhs1, rhs2;
728 : 1204749 : machine_mode lhs_mode;
729 : :
730 : 1204749 : gcc_assert (is_gimple_assign (gs));
731 : 1204749 : lhs = gimple_assign_lhs (gs);
732 : 1204749 : rhs1 = gimple_assign_rhs1 (gs);
733 : 1204749 : lhs_mode = TYPE_MODE (TREE_TYPE (lhs));
734 : :
735 : 1204749 : switch (gimple_assign_rhs_code (gs))
736 : : {
737 : 347670 : case MULT_EXPR:
738 : 347670 : rhs2 = gimple_assign_rhs2 (gs);
739 : :
740 : 347670 : if (tree_fits_shwi_p (rhs2))
741 : 279878 : return mult_by_coeff_cost (tree_to_shwi (rhs2), lhs_mode, speed);
742 : :
743 : 67792 : gcc_assert (TREE_CODE (rhs1) != INTEGER_CST);
744 : 67792 : return mul_cost (speed, lhs_mode);
745 : :
746 : 254021 : case PLUS_EXPR:
747 : 254021 : case POINTER_PLUS_EXPR:
748 : 254021 : case MINUS_EXPR:
749 : 254021 : return add_cost (speed, lhs_mode);
750 : :
751 : 6257 : case NEGATE_EXPR:
752 : 6257 : return neg_cost (speed, lhs_mode);
753 : :
754 : 566336 : CASE_CONVERT:
755 : 1132672 : return convert_cost (lhs_mode, TYPE_MODE (TREE_TYPE (rhs1)), speed);
756 : :
757 : : /* Note that we don't assign costs to copies that in most cases
758 : : will go away. */
759 : : case SSA_NAME:
760 : : return 0;
761 : :
762 : 0 : default:
763 : 0 : ;
764 : : }
765 : :
766 : 0 : gcc_unreachable ();
767 : : }
768 : :
769 : : /* Look up the defining statement for BASE_IN and return a pointer
770 : : to its candidate in the candidate table, if any; otherwise NULL.
771 : : Only CAND_ADD and CAND_MULT candidates are returned. */
772 : :
773 : : static slsr_cand_t
774 : 13555648 : base_cand_from_table (tree base_in)
775 : : {
776 : 13555648 : slsr_cand_t *result;
777 : :
778 : 13555648 : gimple *def = SSA_NAME_DEF_STMT (base_in);
779 : 13555648 : if (!def)
780 : : return (slsr_cand_t) NULL;
781 : :
782 : 13555648 : result = stmt_cand_map->get (def);
783 : :
784 : 13555648 : if (result && (*result)->kind != CAND_REF)
785 : : return *result;
786 : :
787 : : return (slsr_cand_t) NULL;
788 : : }
789 : :
790 : : /* Add an entry to the statement-to-candidate mapping. */
791 : :
792 : : static void
793 : 4999637 : add_cand_for_stmt (gimple *gs, slsr_cand_t c)
794 : : {
795 : 4999637 : gcc_assert (!stmt_cand_map->put (gs, c));
796 : 4999637 : }
797 : :
798 : : /* Given PHI which contains a phi statement, determine whether it
799 : : satisfies all the requirements of a phi candidate. If so, create
800 : : a candidate. Note that a CAND_PHI never has a basis itself, but
801 : : is used to help find a basis for subsequent candidates. */
802 : :
803 : : static void
804 : 4098994 : slsr_process_phi (gphi *phi, bool speed)
805 : : {
806 : 4098994 : unsigned i;
807 : 4098994 : tree arg0_base = NULL_TREE, base_type;
808 : 4098994 : slsr_cand_t c;
809 : 4098994 : class loop *cand_loop = gimple_bb (phi)->loop_father;
810 : 4098994 : unsigned savings = 0;
811 : :
812 : : /* A CAND_PHI requires each of its arguments to have the same
813 : : derived base name. (See the module header commentary for a
814 : : definition of derived base names.) Furthermore, all feeding
815 : : definitions must be in the same position in the loop hierarchy
816 : : as PHI. */
817 : :
818 : 4361285 : for (i = 0; i < gimple_phi_num_args (phi); i++)
819 : : {
820 : 4350111 : slsr_cand_t arg_cand;
821 : 4350111 : tree arg = gimple_phi_arg_def (phi, i);
822 : 4350111 : tree derived_base_name = NULL_TREE;
823 : 4350111 : gimple *arg_stmt = NULL;
824 : 4350111 : basic_block arg_bb = NULL;
825 : :
826 : 4350111 : if (TREE_CODE (arg) != SSA_NAME)
827 : : return;
828 : :
829 : 3968568 : arg_cand = base_cand_from_table (arg);
830 : :
831 : 3968568 : if (arg_cand)
832 : : {
833 : 272728 : while (arg_cand->kind != CAND_ADD && arg_cand->kind != CAND_PHI)
834 : : {
835 : 25238 : if (!arg_cand->next_interp)
836 : : return;
837 : :
838 : 3588 : arg_cand = lookup_cand (arg_cand->next_interp);
839 : : }
840 : :
841 : 247490 : if (!integer_onep (arg_cand->stride))
842 : : return;
843 : :
844 : 151660 : derived_base_name = arg_cand->base_expr;
845 : 151660 : arg_stmt = arg_cand->cand_stmt;
846 : 151660 : arg_bb = gimple_bb (arg_stmt);
847 : :
848 : : /* Gather potential dead code savings if the phi statement
849 : : can be removed later on. */
850 : 151660 : if (uses_consumed_by_stmt (arg, phi))
851 : : {
852 : 85522 : if (gimple_code (arg_stmt) == GIMPLE_PHI)
853 : 3126 : savings += arg_cand->dead_savings;
854 : : else
855 : 82396 : savings += stmt_cost (arg_stmt, speed);
856 : : }
857 : : }
858 : 3699428 : else if (SSA_NAME_IS_DEFAULT_DEF (arg))
859 : : {
860 : 189386 : derived_base_name = arg;
861 : 189386 : arg_bb = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun));
862 : : }
863 : :
864 : 3851088 : if (!arg_bb || arg_bb->loop_father != cand_loop)
865 : : return;
866 : :
867 : 275111 : if (i == 0)
868 : : arg0_base = derived_base_name;
869 : 45947 : else if (!operand_equal_p (derived_base_name, arg0_base, 0))
870 : : return;
871 : : }
872 : :
873 : : /* Create the candidate. "alloc_cand_and_find_basis" is named
874 : : misleadingly for this case, as no basis will be sought for a
875 : : CAND_PHI. */
876 : 11174 : base_type = TREE_TYPE (arg0_base);
877 : :
878 : 11174 : c = alloc_cand_and_find_basis (CAND_PHI, phi, arg0_base,
879 : 11174 : 0, integer_one_node, base_type,
880 : : sizetype, savings);
881 : :
882 : : /* Add the candidate to the statement-candidate mapping. */
883 : 11174 : add_cand_for_stmt (phi, c);
884 : : }
885 : :
886 : : /* Given PBASE which is a pointer to tree, look up the defining
887 : : statement for it and check whether the candidate is in the
888 : : form of:
889 : :
890 : : X = B + (1 * S), S is integer constant
891 : : X = B + (i * S), S is integer one
892 : :
893 : : If so, set PBASE to the candidate's base_expr and return double
894 : : int (i * S).
895 : : Otherwise, just return double int zero. */
896 : :
897 : : static offset_int
898 : 32990 : backtrace_base_for_ref (tree *pbase)
899 : : {
900 : 32990 : tree base_in = *pbase;
901 : 32990 : slsr_cand_t base_cand;
902 : :
903 : 32990 : STRIP_NOPS (base_in);
904 : :
905 : : /* Strip off widening conversion(s) to handle cases where
906 : : e.g. 'B' is widened from an 'int' in order to calculate
907 : : a 64-bit address. */
908 : 31077 : if (CONVERT_EXPR_P (base_in)
909 : 34903 : && legal_cast_p_1 (TREE_TYPE (base_in),
910 : 1913 : TREE_TYPE (TREE_OPERAND (base_in, 0))))
911 : 1591 : base_in = get_unwidened (base_in, NULL_TREE);
912 : :
913 : 32990 : if (TREE_CODE (base_in) != SSA_NAME)
914 : 1127 : return 0;
915 : :
916 : 31863 : base_cand = base_cand_from_table (base_in);
917 : :
918 : 77405 : while (base_cand && base_cand->kind != CAND_PHI)
919 : : {
920 : 30571 : if (base_cand->kind == CAND_ADD
921 : 29693 : && base_cand->index == 1
922 : 46141 : && TREE_CODE (base_cand->stride) == INTEGER_CST)
923 : : {
924 : : /* X = B + (1 * S), S is integer constant. */
925 : 2920 : *pbase = base_cand->base_expr;
926 : 2920 : return wi::to_offset (base_cand->stride);
927 : : }
928 : 27651 : else if (base_cand->kind == CAND_ADD
929 : 26773 : && TREE_CODE (base_cand->stride) == INTEGER_CST
930 : 41623 : && integer_onep (base_cand->stride))
931 : : {
932 : : /* X = B + (i * S), S is integer one. */
933 : 13972 : *pbase = base_cand->base_expr;
934 : 13972 : return base_cand->index;
935 : : }
936 : :
937 : 13679 : base_cand = lookup_cand (base_cand->next_interp);
938 : : }
939 : :
940 : 14971 : return 0;
941 : : }
942 : :
943 : : /* Look for the following pattern:
944 : :
945 : : *PBASE: MEM_REF (T1, C1)
946 : :
947 : : *POFFSET: MULT_EXPR (T2, C3) [C2 is zero]
948 : : or
949 : : MULT_EXPR (PLUS_EXPR (T2, C2), C3)
950 : : or
951 : : MULT_EXPR (MINUS_EXPR (T2, -C2), C3)
952 : :
953 : : *PINDEX: C4 * BITS_PER_UNIT
954 : :
955 : : If not present, leave the input values unchanged and return FALSE.
956 : : Otherwise, modify the input values as follows and return TRUE:
957 : :
958 : : *PBASE: T1
959 : : *POFFSET: MULT_EXPR (T2, C3)
960 : : *PINDEX: C1 + (C2 * C3) + C4
961 : :
962 : : When T2 is recorded by a CAND_ADD in the form of (T2' + C5), it
963 : : will be further restructured to:
964 : :
965 : : *PBASE: T1
966 : : *POFFSET: MULT_EXPR (T2', C3)
967 : : *PINDEX: C1 + (C2 * C3) + C4 + (C5 * C3) */
968 : :
969 : : static bool
970 : 5475899 : restructure_reference (tree *pbase, tree *poffset, offset_int *pindex,
971 : : tree *ptype)
972 : : {
973 : 5475899 : tree base = *pbase, offset = *poffset;
974 : 5475899 : offset_int index = *pindex;
975 : 5475899 : tree mult_op0, t1, t2, type;
976 : 5475899 : offset_int c1, c2, c3, c4, c5;
977 : 5475899 : offset_int mem_offset;
978 : :
979 : 5475899 : if (!base
980 : 5475899 : || !offset
981 : 168315 : || TREE_CODE (base) != MEM_REF
982 : 57758 : || !mem_ref_offset (base).is_constant (&mem_offset)
983 : 57758 : || TREE_CODE (offset) != MULT_EXPR
984 : 33425 : || TREE_CODE (TREE_OPERAND (offset, 1)) != INTEGER_CST
985 : 5509322 : || wi::umod_floor (index, BITS_PER_UNIT) != 0)
986 : 5442476 : return false;
987 : :
988 : 33423 : t1 = TREE_OPERAND (base, 0);
989 : 33423 : c1 = offset_int::from (mem_offset, SIGNED);
990 : 33423 : type = TREE_TYPE (TREE_OPERAND (base, 1));
991 : :
992 : 33423 : mult_op0 = TREE_OPERAND (offset, 0);
993 : 33423 : c3 = wi::to_offset (TREE_OPERAND (offset, 1));
994 : :
995 : 33423 : if (TREE_CODE (mult_op0) == PLUS_EXPR)
996 : :
997 : 2644 : if (TREE_CODE (TREE_OPERAND (mult_op0, 1)) == INTEGER_CST)
998 : : {
999 : 2211 : t2 = TREE_OPERAND (mult_op0, 0);
1000 : 2211 : c2 = wi::to_offset (TREE_OPERAND (mult_op0, 1));
1001 : : }
1002 : : else
1003 : : return false;
1004 : :
1005 : 30779 : else if (TREE_CODE (mult_op0) == MINUS_EXPR)
1006 : :
1007 : 0 : if (TREE_CODE (TREE_OPERAND (mult_op0, 1)) == INTEGER_CST)
1008 : : {
1009 : 0 : t2 = TREE_OPERAND (mult_op0, 0);
1010 : 0 : c2 = -wi::to_offset (TREE_OPERAND (mult_op0, 1));
1011 : : }
1012 : : else
1013 : : return false;
1014 : :
1015 : : else
1016 : : {
1017 : 30779 : t2 = mult_op0;
1018 : 30779 : c2 = 0;
1019 : : }
1020 : :
1021 : 32990 : c4 = index >> LOG2_BITS_PER_UNIT;
1022 : 32990 : c5 = backtrace_base_for_ref (&t2);
1023 : :
1024 : 32990 : *pbase = t1;
1025 : 32990 : *poffset = fold_build2 (MULT_EXPR, sizetype, fold_convert (sizetype, t2),
1026 : : wide_int_to_tree (sizetype, c3));
1027 : 32990 : *pindex = c1 + c2 * c3 + c4 + c5 * c3;
1028 : 32990 : *ptype = type;
1029 : :
1030 : 32990 : return true;
1031 : : }
1032 : :
1033 : : /* Given GS which contains a data reference, create a CAND_REF entry in
1034 : : the candidate table and attempt to find a basis. */
1035 : :
1036 : : static void
1037 : 11526592 : slsr_process_ref (gimple *gs)
1038 : : {
1039 : 11526592 : tree ref_expr, base, offset, type;
1040 : 11526592 : poly_int64 bitsize, bitpos;
1041 : 11526592 : machine_mode mode;
1042 : 11526592 : int unsignedp, reversep, volatilep;
1043 : 11526592 : slsr_cand_t c;
1044 : :
1045 : 23053184 : if (gimple_vdef (gs))
1046 : 6512578 : ref_expr = gimple_assign_lhs (gs);
1047 : : else
1048 : 5014014 : ref_expr = gimple_assign_rhs1 (gs);
1049 : :
1050 : 11526592 : if (!handled_component_p (ref_expr)
1051 : 5559447 : || TREE_CODE (ref_expr) == BIT_FIELD_REF
1052 : 5531322 : || (TREE_CODE (ref_expr) == COMPONENT_REF
1053 : 4858433 : && DECL_BIT_FIELD (TREE_OPERAND (ref_expr, 1))))
1054 : 11493602 : return;
1055 : :
1056 : 5476556 : base = get_inner_reference (ref_expr, &bitsize, &bitpos, &offset, &mode,
1057 : : &unsignedp, &reversep, &volatilep);
1058 : 5476556 : HOST_WIDE_INT cbitpos;
1059 : 5476556 : if (reversep || !bitpos.is_constant (&cbitpos))
1060 : : return;
1061 : 5475899 : offset_int index = cbitpos;
1062 : :
1063 : 5475899 : if (!restructure_reference (&base, &offset, &index, &type))
1064 : : return;
1065 : :
1066 : 32990 : c = alloc_cand_and_find_basis (CAND_REF, gs, base, index, offset,
1067 : : type, sizetype, 0);
1068 : :
1069 : : /* Add the candidate to the statement-candidate mapping. */
1070 : 32990 : add_cand_for_stmt (gs, c);
1071 : : }
1072 : :
1073 : : /* Create a candidate entry for a statement GS, where GS multiplies
1074 : : two SSA names BASE_IN and STRIDE_IN. Propagate any known information
1075 : : about the two SSA names into the new candidate. Return the new
1076 : : candidate. */
1077 : :
1078 : : static slsr_cand_t
1079 : 279694 : create_mul_ssa_cand (gimple *gs, tree base_in, tree stride_in, bool speed)
1080 : : {
1081 : 279694 : tree base = NULL_TREE, stride = NULL_TREE, ctype = NULL_TREE;
1082 : 279694 : tree stype = NULL_TREE;
1083 : 279694 : offset_int index;
1084 : 279694 : unsigned savings = 0;
1085 : 279694 : slsr_cand_t c;
1086 : 279694 : slsr_cand_t base_cand = base_cand_from_table (base_in);
1087 : :
1088 : : /* Look at all interpretations of the base candidate, if necessary,
1089 : : to find information to propagate into this candidate. */
1090 : 669039 : while (base_cand && !base && base_cand->kind != CAND_PHI)
1091 : : {
1092 : :
1093 : 109651 : if (base_cand->kind == CAND_MULT && integer_onep (base_cand->stride))
1094 : : {
1095 : : /* Y = (B + i') * 1
1096 : : X = Y * Z
1097 : : ================
1098 : : X = (B + i') * Z */
1099 : 84 : base = base_cand->base_expr;
1100 : 84 : index = base_cand->index;
1101 : 84 : stride = stride_in;
1102 : 84 : ctype = base_cand->cand_type;
1103 : 84 : stype = TREE_TYPE (stride_in);
1104 : 84 : if (has_single_use (base_in))
1105 : 126 : savings = (base_cand->dead_savings
1106 : 63 : + stmt_cost (base_cand->cand_stmt, speed));
1107 : : }
1108 : 109567 : else if (base_cand->kind == CAND_ADD
1109 : 95272 : && TREE_CODE (base_cand->stride) == INTEGER_CST)
1110 : : {
1111 : : /* Y = B + (i' * S), S constant
1112 : : X = Y * Z
1113 : : ============================
1114 : : X = B + ((i' * S) * Z) */
1115 : 69208 : base = base_cand->base_expr;
1116 : 69208 : index = base_cand->index * wi::to_offset (base_cand->stride);
1117 : 69208 : stride = stride_in;
1118 : 69208 : ctype = base_cand->cand_type;
1119 : 69208 : stype = TREE_TYPE (stride_in);
1120 : 69208 : if (has_single_use (base_in))
1121 : 82278 : savings = (base_cand->dead_savings
1122 : 41139 : + stmt_cost (base_cand->cand_stmt, speed));
1123 : : }
1124 : :
1125 : 109651 : base_cand = lookup_cand (base_cand->next_interp);
1126 : : }
1127 : :
1128 : 279694 : if (!base)
1129 : : {
1130 : : /* No interpretations had anything useful to propagate, so
1131 : : produce X = (Y + 0) * Z. */
1132 : 210402 : base = base_in;
1133 : 210402 : index = 0;
1134 : 210402 : stride = stride_in;
1135 : 210402 : ctype = TREE_TYPE (base_in);
1136 : 210402 : stype = TREE_TYPE (stride_in);
1137 : : }
1138 : :
1139 : 279694 : c = alloc_cand_and_find_basis (CAND_MULT, gs, base, index, stride,
1140 : : ctype, stype, savings);
1141 : 279694 : return c;
1142 : : }
1143 : :
1144 : : /* Create a candidate entry for a statement GS, where GS multiplies
1145 : : SSA name BASE_IN by constant STRIDE_IN. Propagate any known
1146 : : information about BASE_IN into the new candidate. Return the new
1147 : : candidate. */
1148 : :
1149 : : static slsr_cand_t
1150 : 565238 : create_mul_imm_cand (gimple *gs, tree base_in, tree stride_in, bool speed)
1151 : : {
1152 : 565238 : tree base = NULL_TREE, stride = NULL_TREE, ctype = NULL_TREE;
1153 : 565238 : offset_int index, temp;
1154 : 565238 : unsigned savings = 0;
1155 : 565238 : slsr_cand_t c;
1156 : 565238 : slsr_cand_t base_cand = base_cand_from_table (base_in);
1157 : :
1158 : : /* Look at all interpretations of the base candidate, if necessary,
1159 : : to find information to propagate into this candidate. */
1160 : 1479731 : while (base_cand && !base && base_cand->kind != CAND_PHI)
1161 : : {
1162 : 349255 : if (base_cand->kind == CAND_MULT
1163 : 29676 : && TREE_CODE (base_cand->stride) == INTEGER_CST)
1164 : : {
1165 : : /* Y = (B + i') * S, S constant
1166 : : X = Y * c
1167 : : ============================
1168 : : X = (B + i') * (S * c) */
1169 : 11398 : temp = wi::to_offset (base_cand->stride) * wi::to_offset (stride_in);
1170 : 11398 : if (wi::fits_to_tree_p (temp, TREE_TYPE (stride_in)))
1171 : : {
1172 : 10968 : base = base_cand->base_expr;
1173 : 10968 : index = base_cand->index;
1174 : 10968 : stride = wide_int_to_tree (TREE_TYPE (stride_in), temp);
1175 : 10968 : ctype = base_cand->cand_type;
1176 : 10968 : if (has_single_use (base_in))
1177 : 13020 : savings = (base_cand->dead_savings
1178 : 6510 : + stmt_cost (base_cand->cand_stmt, speed));
1179 : : }
1180 : : }
1181 : 337857 : else if (base_cand->kind == CAND_ADD && integer_onep (base_cand->stride))
1182 : : {
1183 : : /* Y = B + (i' * 1)
1184 : : X = Y * c
1185 : : ===========================
1186 : : X = (B + i') * c */
1187 : 223804 : base = base_cand->base_expr;
1188 : 223804 : index = base_cand->index;
1189 : 223804 : stride = stride_in;
1190 : 223804 : ctype = base_cand->cand_type;
1191 : 223804 : if (has_single_use (base_in))
1192 : 365428 : savings = (base_cand->dead_savings
1193 : 182714 : + stmt_cost (base_cand->cand_stmt, speed));
1194 : : }
1195 : 114053 : else if (base_cand->kind == CAND_ADD
1196 : 192989 : && base_cand->index == 1
1197 : 192989 : && TREE_CODE (base_cand->stride) == INTEGER_CST)
1198 : : {
1199 : : /* Y = B + (1 * S), S constant
1200 : : X = Y * c
1201 : : ===========================
1202 : : X = (B + S) * c */
1203 : 0 : base = base_cand->base_expr;
1204 : 0 : index = wi::to_offset (base_cand->stride);
1205 : 0 : stride = stride_in;
1206 : 0 : ctype = base_cand->cand_type;
1207 : 0 : if (has_single_use (base_in))
1208 : 0 : savings = (base_cand->dead_savings
1209 : 0 : + stmt_cost (base_cand->cand_stmt, speed));
1210 : : }
1211 : :
1212 : 349255 : base_cand = lookup_cand (base_cand->next_interp);
1213 : : }
1214 : :
1215 : 565238 : if (!base)
1216 : : {
1217 : : /* No interpretations had anything useful to propagate, so
1218 : : produce X = (Y + 0) * c. */
1219 : 330466 : base = base_in;
1220 : 330466 : index = 0;
1221 : 330466 : stride = stride_in;
1222 : 330466 : ctype = TREE_TYPE (base_in);
1223 : : }
1224 : :
1225 : 565238 : c = alloc_cand_and_find_basis (CAND_MULT, gs, base, index, stride,
1226 : : ctype, sizetype, savings);
1227 : 565238 : return c;
1228 : : }
1229 : :
1230 : : /* Given GS which is a multiply of scalar integers, make an appropriate
1231 : : entry in the candidate table. If this is a multiply of two SSA names,
1232 : : create two CAND_MULT interpretations and attempt to find a basis for
1233 : : each of them. Otherwise, create a single CAND_MULT and attempt to
1234 : : find a basis. */
1235 : :
1236 : : static void
1237 : 637187 : slsr_process_mul (gimple *gs, tree rhs1, tree rhs2, bool speed)
1238 : : {
1239 : 637187 : slsr_cand_t c, c2;
1240 : :
1241 : : /* If this is a multiply of an SSA name with itself, it is highly
1242 : : unlikely that we will get a strength reduction opportunity, so
1243 : : don't record it as a candidate. This simplifies the logic for
1244 : : finding a basis, so if this is removed that must be considered. */
1245 : 637187 : if (rhs1 == rhs2)
1246 : : return;
1247 : :
1248 : 629834 : if (TREE_CODE (rhs2) == SSA_NAME)
1249 : : {
1250 : : /* Record an interpretation of this statement in the candidate table
1251 : : assuming RHS1 is the base expression and RHS2 is the stride. */
1252 : 139847 : c = create_mul_ssa_cand (gs, rhs1, rhs2, speed);
1253 : :
1254 : : /* Add the first interpretation to the statement-candidate mapping. */
1255 : 139847 : add_cand_for_stmt (gs, c);
1256 : :
1257 : : /* Record another interpretation of this statement assuming RHS1
1258 : : is the stride and RHS2 is the base expression. */
1259 : 139847 : c2 = create_mul_ssa_cand (gs, rhs2, rhs1, speed);
1260 : 139847 : c->next_interp = c2->cand_num;
1261 : 139847 : c2->first_interp = c->cand_num;
1262 : : }
1263 : 489987 : else if (TREE_CODE (rhs2) == INTEGER_CST && !integer_zerop (rhs2))
1264 : : {
1265 : : /* Record an interpretation for the multiply-immediate. */
1266 : 489987 : c = create_mul_imm_cand (gs, rhs1, rhs2, speed);
1267 : :
1268 : : /* Add the interpretation to the statement-candidate mapping. */
1269 : 489987 : add_cand_for_stmt (gs, c);
1270 : : }
1271 : : }
1272 : :
1273 : : /* Create a candidate entry for a statement GS, where GS adds two
1274 : : SSA names BASE_IN and ADDEND_IN if SUBTRACT_P is false, and
1275 : : subtracts ADDEND_IN from BASE_IN otherwise. Propagate any known
1276 : : information about the two SSA names into the new candidate.
1277 : : Return the new candidate. */
1278 : :
1279 : : static slsr_cand_t
1280 : 1681000 : create_add_ssa_cand (gimple *gs, tree base_in, tree addend_in,
1281 : : bool subtract_p, bool speed)
1282 : : {
1283 : 1681000 : tree base = NULL_TREE, stride = NULL_TREE, ctype = NULL_TREE;
1284 : 1681000 : tree stype = NULL_TREE;
1285 : 1681000 : offset_int index;
1286 : 1681000 : unsigned savings = 0;
1287 : 1681000 : slsr_cand_t c;
1288 : 1681000 : slsr_cand_t base_cand = base_cand_from_table (base_in);
1289 : 1681000 : slsr_cand_t addend_cand = base_cand_from_table (addend_in);
1290 : :
1291 : : /* The most useful transformation is a multiply-immediate feeding
1292 : : an add or subtract. Look for that first. */
1293 : 4763614 : while (addend_cand && !base && addend_cand->kind != CAND_PHI)
1294 : : {
1295 : 1401614 : if (addend_cand->kind == CAND_MULT
1296 : 1552498 : && addend_cand->index == 0
1297 : 2057174 : && TREE_CODE (addend_cand->stride) == INTEGER_CST)
1298 : : {
1299 : : /* Z = (B + 0) * S, S constant
1300 : : X = Y +/- Z
1301 : : ===========================
1302 : : X = Y + ((+/-1 * S) * B) */
1303 : 504676 : base = base_in;
1304 : 504676 : index = wi::to_offset (addend_cand->stride);
1305 : 504676 : if (subtract_p)
1306 : 36830 : index = -index;
1307 : 504676 : stride = addend_cand->base_expr;
1308 : 504676 : ctype = TREE_TYPE (base_in);
1309 : 504676 : stype = addend_cand->cand_type;
1310 : 504676 : if (has_single_use (addend_in))
1311 : 826946 : savings = (addend_cand->dead_savings
1312 : 413473 : + stmt_cost (addend_cand->cand_stmt, speed));
1313 : : }
1314 : :
1315 : 1401614 : addend_cand = lookup_cand (addend_cand->next_interp);
1316 : : }
1317 : :
1318 : 2377578 : while (base_cand && !base && base_cand->kind != CAND_PHI)
1319 : : {
1320 : 696578 : if (base_cand->kind == CAND_ADD
1321 : 696578 : && (base_cand->index == 0
1322 : 404326 : || operand_equal_p (base_cand->stride,
1323 : 404326 : integer_zero_node, 0)))
1324 : : {
1325 : : /* Y = B + (i' * S), i' * S = 0
1326 : : X = Y +/- Z
1327 : : ============================
1328 : : X = B + (+/-1 * Z) */
1329 : 88953 : base = base_cand->base_expr;
1330 : 167987 : index = subtract_p ? -1 : 1;
1331 : 88953 : stride = addend_in;
1332 : 88953 : ctype = base_cand->cand_type;
1333 : 177906 : stype = (TREE_CODE (addend_in) == INTEGER_CST ? sizetype
1334 : 88953 : : TREE_TYPE (addend_in));
1335 : 88953 : if (has_single_use (base_in))
1336 : 126996 : savings = (base_cand->dead_savings
1337 : 63498 : + stmt_cost (base_cand->cand_stmt, speed));
1338 : : }
1339 : 607625 : else if (subtract_p)
1340 : : {
1341 : 65192 : slsr_cand_t subtrahend_cand = base_cand_from_table (addend_in);
1342 : :
1343 : 155882 : while (subtrahend_cand && !base && subtrahend_cand->kind != CAND_PHI)
1344 : : {
1345 : 25498 : if (subtrahend_cand->kind == CAND_MULT
1346 : 33709 : && subtrahend_cand->index == 0
1347 : 33709 : && TREE_CODE (subtrahend_cand->stride) == INTEGER_CST)
1348 : : {
1349 : : /* Z = (B + 0) * S, S constant
1350 : : X = Y - Z
1351 : : ===========================
1352 : : Value: X = Y + ((-1 * S) * B) */
1353 : 0 : base = base_in;
1354 : 0 : index = wi::to_offset (subtrahend_cand->stride);
1355 : 0 : index = -index;
1356 : 0 : stride = subtrahend_cand->base_expr;
1357 : 0 : ctype = TREE_TYPE (base_in);
1358 : 0 : stype = subtrahend_cand->cand_type;
1359 : 0 : if (has_single_use (addend_in))
1360 : 0 : savings = (subtrahend_cand->dead_savings
1361 : 0 : + stmt_cost (subtrahend_cand->cand_stmt, speed));
1362 : : }
1363 : :
1364 : 25498 : subtrahend_cand = lookup_cand (subtrahend_cand->next_interp);
1365 : : }
1366 : : }
1367 : :
1368 : 696578 : base_cand = lookup_cand (base_cand->next_interp);
1369 : : }
1370 : :
1371 : 1681000 : if (!base)
1372 : : {
1373 : : /* No interpretations had anything useful to propagate, so
1374 : : produce X = Y + (1 * Z). */
1375 : 1087371 : base = base_in;
1376 : 2029343 : index = subtract_p ? -1 : 1;
1377 : 1087371 : stride = addend_in;
1378 : 1087371 : ctype = TREE_TYPE (base_in);
1379 : 2174742 : stype = (TREE_CODE (addend_in) == INTEGER_CST ? sizetype
1380 : 1087371 : : TREE_TYPE (addend_in));
1381 : : }
1382 : :
1383 : 1681000 : c = alloc_cand_and_find_basis (CAND_ADD, gs, base, index, stride,
1384 : : ctype, stype, savings);
1385 : 1681000 : return c;
1386 : : }
1387 : :
1388 : : /* Create a candidate entry for a statement GS, where GS adds SSA
1389 : : name BASE_IN to constant INDEX_IN. Propagate any known information
1390 : : about BASE_IN into the new candidate. Return the new candidate. */
1391 : :
1392 : : static slsr_cand_t
1393 : 1611679 : create_add_imm_cand (gimple *gs, tree base_in, const offset_int &index_in,
1394 : : bool speed)
1395 : : {
1396 : 1611679 : enum cand_kind kind = CAND_ADD;
1397 : 1611679 : tree base = NULL_TREE, stride = NULL_TREE, ctype = NULL_TREE;
1398 : 1611679 : tree stype = NULL_TREE;
1399 : 1611679 : offset_int index, multiple;
1400 : 1611679 : unsigned savings = 0;
1401 : 1611679 : slsr_cand_t c;
1402 : 1611679 : slsr_cand_t base_cand = base_cand_from_table (base_in);
1403 : :
1404 : 3571512 : while (base_cand && !base && base_cand->kind != CAND_PHI)
1405 : : {
1406 : 348154 : signop sign = TYPE_SIGN (TREE_TYPE (base_cand->stride));
1407 : :
1408 : 348154 : if (TREE_CODE (base_cand->stride) == INTEGER_CST
1409 : 348154 : && wi::multiple_of_p (index_in, wi::to_offset (base_cand->stride),
1410 : : sign, &multiple))
1411 : : {
1412 : : /* Y = (B + i') * S, S constant, c = kS for some integer k
1413 : : X = Y + c
1414 : : ============================
1415 : : X = (B + (i'+ k)) * S
1416 : : OR
1417 : : Y = B + (i' * S), S constant, c = kS for some integer k
1418 : : X = Y + c
1419 : : ============================
1420 : : X = (B + (i'+ k)) * S */
1421 : 200409 : kind = base_cand->kind;
1422 : 200409 : base = base_cand->base_expr;
1423 : 200409 : index = base_cand->index + multiple;
1424 : 200409 : stride = base_cand->stride;
1425 : 200409 : ctype = base_cand->cand_type;
1426 : 200409 : stype = base_cand->stride_type;
1427 : 200409 : if (has_single_use (base_in))
1428 : 246596 : savings = (base_cand->dead_savings
1429 : 123298 : + stmt_cost (base_cand->cand_stmt, speed));
1430 : : }
1431 : :
1432 : 348154 : base_cand = lookup_cand (base_cand->next_interp);
1433 : : }
1434 : :
1435 : 1611679 : if (!base)
1436 : : {
1437 : : /* No interpretations had anything useful to propagate, so
1438 : : produce X = Y + (c * 1). */
1439 : 1411270 : kind = CAND_ADD;
1440 : 1411270 : base = base_in;
1441 : 1411270 : index = index_in;
1442 : 1411270 : stride = integer_one_node;
1443 : 1411270 : ctype = TREE_TYPE (base_in);
1444 : 1411270 : stype = sizetype;
1445 : : }
1446 : :
1447 : 1611679 : c = alloc_cand_and_find_basis (kind, gs, base, index, stride,
1448 : : ctype, stype, savings);
1449 : 1611679 : return c;
1450 : : }
1451 : :
1452 : : /* Given GS which is an add or subtract of scalar integers or pointers,
1453 : : make at least one appropriate entry in the candidate table. */
1454 : :
1455 : : static void
1456 : 2753360 : slsr_process_add (gimple *gs, tree rhs1, tree rhs2, bool speed)
1457 : : {
1458 : 2753360 : bool subtract_p = gimple_assign_rhs_code (gs) == MINUS_EXPR;
1459 : 2753360 : slsr_cand_t c = NULL, c2;
1460 : :
1461 : 2753360 : if (TREE_CODE (rhs2) == SSA_NAME)
1462 : : {
1463 : : /* First record an interpretation assuming RHS1 is the base expression
1464 : : and RHS2 is the stride. But it doesn't make sense for the
1465 : : stride to be a pointer, so don't record a candidate in that case. */
1466 : 1141681 : if (!POINTER_TYPE_P (TREE_TYPE (rhs2)))
1467 : : {
1468 : 1141681 : c = create_add_ssa_cand (gs, rhs1, rhs2, subtract_p, speed);
1469 : :
1470 : : /* Add the first interpretation to the statement-candidate
1471 : : mapping. */
1472 : 1141681 : add_cand_for_stmt (gs, c);
1473 : : }
1474 : :
1475 : : /* If the two RHS operands are identical, or this is a subtract,
1476 : : we're done. */
1477 : 1141681 : if (operand_equal_p (rhs1, rhs2, 0) || subtract_p)
1478 : : return;
1479 : :
1480 : : /* Otherwise, record another interpretation assuming RHS2 is the
1481 : : base expression and RHS1 is the stride, again provided that the
1482 : : stride is not a pointer. */
1483 : 949527 : if (!POINTER_TYPE_P (TREE_TYPE (rhs1)))
1484 : : {
1485 : 539319 : c2 = create_add_ssa_cand (gs, rhs2, rhs1, false, speed);
1486 : 539319 : if (c)
1487 : : {
1488 : 539319 : c->next_interp = c2->cand_num;
1489 : 539319 : c2->first_interp = c->cand_num;
1490 : : }
1491 : : else
1492 : 0 : add_cand_for_stmt (gs, c2);
1493 : : }
1494 : : }
1495 : 1611679 : else if (TREE_CODE (rhs2) == INTEGER_CST)
1496 : : {
1497 : : /* Record an interpretation for the add-immediate. */
1498 : 1611679 : offset_int index = wi::to_offset (rhs2);
1499 : 1611679 : if (subtract_p)
1500 : 22616 : index = -index;
1501 : :
1502 : 1611679 : c = create_add_imm_cand (gs, rhs1, index, speed);
1503 : :
1504 : : /* Add the interpretation to the statement-candidate mapping. */
1505 : 1611679 : add_cand_for_stmt (gs, c);
1506 : : }
1507 : : }
1508 : :
1509 : : /* Given GS which is a negate of a scalar integer, make an appropriate
1510 : : entry in the candidate table. A negate is equivalent to a multiply
1511 : : by -1. */
1512 : :
1513 : : static void
1514 : 75251 : slsr_process_neg (gimple *gs, tree rhs1, bool speed)
1515 : : {
1516 : : /* Record a CAND_MULT interpretation for the multiply by -1. */
1517 : 75251 : slsr_cand_t c = create_mul_imm_cand (gs, rhs1, integer_minus_one_node, speed);
1518 : :
1519 : : /* Add the interpretation to the statement-candidate mapping. */
1520 : 75251 : add_cand_for_stmt (gs, c);
1521 : 75251 : }
1522 : :
1523 : : /* Help function for legal_cast_p, operating on two trees. Checks
1524 : : whether it's allowable to cast from RHS to LHS. See legal_cast_p
1525 : : for more details. */
1526 : :
1527 : : static bool
1528 : 2565277 : legal_cast_p_1 (tree lhs_type, tree rhs_type)
1529 : : {
1530 : 2565277 : unsigned lhs_size, rhs_size;
1531 : 2565277 : bool lhs_wraps, rhs_wraps;
1532 : :
1533 : 2565277 : lhs_size = TYPE_PRECISION (lhs_type);
1534 : 2565277 : rhs_size = TYPE_PRECISION (rhs_type);
1535 : 2565277 : lhs_wraps = ANY_INTEGRAL_TYPE_P (lhs_type) && TYPE_OVERFLOW_WRAPS (lhs_type);
1536 : 2565277 : rhs_wraps = ANY_INTEGRAL_TYPE_P (rhs_type) && TYPE_OVERFLOW_WRAPS (rhs_type);
1537 : :
1538 : 2565277 : if (lhs_size < rhs_size
1539 : 2323198 : || (rhs_wraps && !lhs_wraps)
1540 : 1515146 : || (rhs_wraps && lhs_wraps && rhs_size != lhs_size))
1541 : 1212049 : return false;
1542 : :
1543 : : return true;
1544 : : }
1545 : :
1546 : : /* Return TRUE if GS is a statement that defines an SSA name from
1547 : : a conversion and is legal for us to combine with an add and multiply
1548 : : in the candidate table. For example, suppose we have:
1549 : :
1550 : : A = B + i;
1551 : : C = (type) A;
1552 : : D = C * S;
1553 : :
1554 : : Without the type-cast, we would create a CAND_MULT for D with base B,
1555 : : index i, and stride S. We want to record this candidate only if it
1556 : : is equivalent to apply the type cast following the multiply:
1557 : :
1558 : : A = B + i;
1559 : : E = A * S;
1560 : : D = (type) E;
1561 : :
1562 : : We will record the type with the candidate for D. This allows us
1563 : : to use a similar previous candidate as a basis. If we have earlier seen
1564 : :
1565 : : A' = B + i';
1566 : : C' = (type) A';
1567 : : D' = C' * S;
1568 : :
1569 : : we can replace D with
1570 : :
1571 : : D = D' + (i - i') * S;
1572 : :
1573 : : But if moving the type-cast would change semantics, we mustn't do this.
1574 : :
1575 : : This is legitimate for casts from a non-wrapping integral type to
1576 : : any integral type of the same or larger size. It is not legitimate
1577 : : to convert a wrapping type to a non-wrapping type, or to a wrapping
1578 : : type of a different size. I.e., with a wrapping type, we must
1579 : : assume that the addition B + i could wrap, in which case performing
1580 : : the multiply before or after one of the "illegal" type casts will
1581 : : have different semantics. */
1582 : :
1583 : : static bool
1584 : 2561318 : legal_cast_p (gimple *gs, tree rhs)
1585 : : {
1586 : 2561318 : if (!is_gimple_assign (gs)
1587 : 2561318 : || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (gs)))
1588 : : return false;
1589 : :
1590 : 2561318 : return legal_cast_p_1 (TREE_TYPE (gimple_assign_lhs (gs)), TREE_TYPE (rhs));
1591 : : }
1592 : :
1593 : : /* Given GS which is a cast to a scalar integer type, determine whether
1594 : : the cast is legal for strength reduction. If so, make at least one
1595 : : appropriate entry in the candidate table. */
1596 : :
1597 : : static void
1598 : 2561318 : slsr_process_cast (gimple *gs, tree rhs1, bool speed)
1599 : : {
1600 : 2561318 : tree lhs, ctype;
1601 : 2561318 : slsr_cand_t base_cand, c = NULL, c2;
1602 : 2561318 : unsigned savings = 0;
1603 : :
1604 : 2561318 : if (!legal_cast_p (gs, rhs1))
1605 : : return;
1606 : :
1607 : 1349621 : lhs = gimple_assign_lhs (gs);
1608 : 1349621 : base_cand = base_cand_from_table (rhs1);
1609 : 1349621 : ctype = TREE_TYPE (lhs);
1610 : :
1611 : 1349621 : if (base_cand && base_cand->kind != CAND_PHI)
1612 : : {
1613 : : slsr_cand_t first_cand = NULL;
1614 : :
1615 : 615988 : while (base_cand)
1616 : : {
1617 : : /* Propagate all data from the base candidate except the type,
1618 : : which comes from the cast, and the base candidate's cast,
1619 : : which is no longer applicable. */
1620 : 348505 : if (has_single_use (rhs1))
1621 : 445084 : savings = (base_cand->dead_savings
1622 : 222542 : + stmt_cost (base_cand->cand_stmt, speed));
1623 : :
1624 : 697010 : c = alloc_cand_and_find_basis (base_cand->kind, gs,
1625 : : base_cand->base_expr,
1626 : 348505 : base_cand->index, base_cand->stride,
1627 : : ctype, base_cand->stride_type,
1628 : : savings);
1629 : 348505 : if (!first_cand)
1630 : 267483 : first_cand = c;
1631 : :
1632 : 348505 : if (first_cand != c)
1633 : 81022 : c->first_interp = first_cand->cand_num;
1634 : :
1635 : 348505 : base_cand = lookup_cand (base_cand->next_interp);
1636 : : }
1637 : : }
1638 : : else
1639 : : {
1640 : : /* If nothing is known about the RHS, create fresh CAND_ADD and
1641 : : CAND_MULT interpretations:
1642 : :
1643 : : X = Y + (0 * 1)
1644 : : X = (Y + 0) * 1
1645 : :
1646 : : The first of these is somewhat arbitrary, but the choice of
1647 : : 1 for the stride simplifies the logic for propagating casts
1648 : : into their uses. */
1649 : 1082138 : c = alloc_cand_and_find_basis (CAND_ADD, gs, rhs1, 0,
1650 : : integer_one_node, ctype, sizetype, 0);
1651 : 1082138 : c2 = alloc_cand_and_find_basis (CAND_MULT, gs, rhs1, 0,
1652 : : integer_one_node, ctype, sizetype, 0);
1653 : 1082138 : c->next_interp = c2->cand_num;
1654 : 1082138 : c2->first_interp = c->cand_num;
1655 : : }
1656 : :
1657 : : /* Add the first (or only) interpretation to the statement-candidate
1658 : : mapping. */
1659 : 1349621 : add_cand_for_stmt (gs, c);
1660 : : }
1661 : :
1662 : : /* Given GS which is a copy of a scalar integer type, make at least one
1663 : : appropriate entry in the candidate table.
1664 : :
1665 : : This interface is included for completeness, but is unnecessary
1666 : : if this pass immediately follows a pass that performs copy
1667 : : propagation, such as DOM. */
1668 : :
1669 : : static void
1670 : 147407 : slsr_process_copy (gimple *gs, tree rhs1, bool speed)
1671 : : {
1672 : 147407 : slsr_cand_t base_cand, c = NULL, c2;
1673 : 147407 : unsigned savings = 0;
1674 : :
1675 : 147407 : base_cand = base_cand_from_table (rhs1);
1676 : :
1677 : 147407 : if (base_cand && base_cand->kind != CAND_PHI)
1678 : : {
1679 : : slsr_cand_t first_cand = NULL;
1680 : :
1681 : 129035 : while (base_cand)
1682 : : {
1683 : : /* Propagate all data from the base candidate. */
1684 : 75172 : if (has_single_use (rhs1))
1685 : 138150 : savings = (base_cand->dead_savings
1686 : 69075 : + stmt_cost (base_cand->cand_stmt, speed));
1687 : :
1688 : 150344 : c = alloc_cand_and_find_basis (base_cand->kind, gs,
1689 : : base_cand->base_expr,
1690 : 75172 : base_cand->index, base_cand->stride,
1691 : : base_cand->cand_type,
1692 : : base_cand->stride_type, savings);
1693 : 75172 : if (!first_cand)
1694 : 53863 : first_cand = c;
1695 : :
1696 : 75172 : if (first_cand != c)
1697 : 21309 : c->first_interp = first_cand->cand_num;
1698 : :
1699 : 75172 : base_cand = lookup_cand (base_cand->next_interp);
1700 : : }
1701 : : }
1702 : : else
1703 : : {
1704 : : /* If nothing is known about the RHS, create fresh CAND_ADD and
1705 : : CAND_MULT interpretations:
1706 : :
1707 : : X = Y + (0 * 1)
1708 : : X = (Y + 0) * 1
1709 : :
1710 : : The first of these is somewhat arbitrary, but the choice of
1711 : : 1 for the stride simplifies the logic for propagating casts
1712 : : into their uses. */
1713 : 93544 : c = alloc_cand_and_find_basis (CAND_ADD, gs, rhs1, 0,
1714 : 93544 : integer_one_node, TREE_TYPE (rhs1),
1715 : : sizetype, 0);
1716 : 93544 : c2 = alloc_cand_and_find_basis (CAND_MULT, gs, rhs1, 0,
1717 : 93544 : integer_one_node, TREE_TYPE (rhs1),
1718 : : sizetype, 0);
1719 : 93544 : c->next_interp = c2->cand_num;
1720 : 93544 : c2->first_interp = c->cand_num;
1721 : : }
1722 : :
1723 : : /* Add the first (or only) interpretation to the statement-candidate
1724 : : mapping. */
1725 : 147407 : add_cand_for_stmt (gs, c);
1726 : 147407 : }
1727 : :
1728 : 1988408 : class find_candidates_dom_walker : public dom_walker
1729 : : {
1730 : : public:
1731 : 994204 : find_candidates_dom_walker (cdi_direction direction)
1732 : 1988408 : : dom_walker (direction) {}
1733 : : edge before_dom_children (basic_block) final override;
1734 : : };
1735 : :
1736 : : /* Find strength-reduction candidates in block BB. */
1737 : :
1738 : : edge
1739 : 10332890 : find_candidates_dom_walker::before_dom_children (basic_block bb)
1740 : : {
1741 : 10332890 : bool speed = optimize_bb_for_speed_p (bb);
1742 : :
1743 : 14431884 : for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
1744 : 4098994 : gsi_next (&gsi))
1745 : 4098994 : slsr_process_phi (gsi.phi (), speed);
1746 : :
1747 : 93238447 : for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi);
1748 : 72572667 : gsi_next (&gsi))
1749 : : {
1750 : 72572667 : gimple *gs = gsi_stmt (gsi);
1751 : :
1752 : 72572667 : if (stmt_could_throw_p (cfun, gs))
1753 : 3124753 : continue;
1754 : :
1755 : 94982121 : if (gimple_vuse (gs) && gimple_assign_single_p (gs))
1756 : 11526592 : slsr_process_ref (gs);
1757 : :
1758 : 57921322 : else if (is_gimple_assign (gs)
1759 : 57921322 : && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_lhs (gs)))
1760 : 2885643 : || POINTER_TYPE_P (TREE_TYPE (gimple_assign_lhs (gs)))))
1761 : : {
1762 : 8720258 : tree rhs1 = NULL_TREE, rhs2 = NULL_TREE;
1763 : :
1764 : 8720258 : switch (gimple_assign_rhs_code (gs))
1765 : : {
1766 : 2518322 : case MULT_EXPR:
1767 : 2518322 : case PLUS_EXPR:
1768 : 2518322 : rhs1 = gimple_assign_rhs1 (gs);
1769 : 2518322 : rhs2 = gimple_assign_rhs2 (gs);
1770 : : /* Should never happen, but currently some buggy situations
1771 : : in earlier phases put constants in rhs1. */
1772 : 2518322 : if (TREE_CODE (rhs1) != SSA_NAME)
1773 : 3 : continue;
1774 : : break;
1775 : :
1776 : : /* Possible future opportunity: rhs1 of a ptr+ can be
1777 : : an ADDR_EXPR. */
1778 : 972748 : case POINTER_PLUS_EXPR:
1779 : 972748 : case MINUS_EXPR:
1780 : 972748 : rhs2 = gimple_assign_rhs2 (gs);
1781 : 3931834 : gcc_fallthrough ();
1782 : :
1783 : 3931834 : CASE_CONVERT:
1784 : 3931834 : case SSA_NAME:
1785 : 3931834 : case NEGATE_EXPR:
1786 : 3931834 : rhs1 = gimple_assign_rhs1 (gs);
1787 : 3931834 : if (TREE_CODE (rhs1) != SSA_NAME)
1788 : 275630 : continue;
1789 : : break;
1790 : :
1791 : 8444625 : default:
1792 : 8444625 : ;
1793 : : }
1794 : :
1795 : 8444625 : switch (gimple_assign_rhs_code (gs))
1796 : : {
1797 : 637187 : case MULT_EXPR:
1798 : 637187 : slsr_process_mul (gs, rhs1, rhs2, speed);
1799 : 637187 : break;
1800 : :
1801 : 2753360 : case PLUS_EXPR:
1802 : 2753360 : case POINTER_PLUS_EXPR:
1803 : 2753360 : case MINUS_EXPR:
1804 : 2753360 : slsr_process_add (gs, rhs1, rhs2, speed);
1805 : 2753360 : break;
1806 : :
1807 : 75251 : case NEGATE_EXPR:
1808 : 75251 : slsr_process_neg (gs, rhs1, speed);
1809 : 75251 : break;
1810 : :
1811 : 2561318 : CASE_CONVERT:
1812 : 2561318 : slsr_process_cast (gs, rhs1, speed);
1813 : 2561318 : break;
1814 : :
1815 : 147407 : case SSA_NAME:
1816 : 147407 : slsr_process_copy (gs, rhs1, speed);
1817 : 147407 : break;
1818 : :
1819 : : default:
1820 : : ;
1821 : : }
1822 : : }
1823 : : }
1824 : 10332890 : return NULL;
1825 : : }
1826 : :
1827 : : /* Dump a candidate for debug. */
1828 : :
1829 : : static void
1830 : 31 : dump_candidate (slsr_cand_t c)
1831 : : {
1832 : 31 : fprintf (dump_file, "%3d [%d] ", c->cand_num,
1833 : 31 : gimple_bb (c->cand_stmt)->index);
1834 : 31 : print_gimple_stmt (dump_file, c->cand_stmt, 0);
1835 : 31 : switch (c->kind)
1836 : : {
1837 : 3 : case CAND_MULT:
1838 : 3 : fputs (" MULT : (", dump_file);
1839 : 3 : print_generic_expr (dump_file, c->base_expr);
1840 : 3 : fputs (" + ", dump_file);
1841 : 3 : print_decs (c->index, dump_file);
1842 : 3 : fputs (") * ", dump_file);
1843 : 3 : if (TREE_CODE (c->stride) != INTEGER_CST
1844 : 3 : && c->stride_type != TREE_TYPE (c->stride))
1845 : : {
1846 : 0 : fputs ("(", dump_file);
1847 : 0 : print_generic_expr (dump_file, c->stride_type);
1848 : 0 : fputs (")", dump_file);
1849 : : }
1850 : 3 : print_generic_expr (dump_file, c->stride);
1851 : 3 : fputs (" : ", dump_file);
1852 : 3 : break;
1853 : 17 : case CAND_ADD:
1854 : 17 : fputs (" ADD : ", dump_file);
1855 : 17 : print_generic_expr (dump_file, c->base_expr);
1856 : 17 : fputs (" + (", dump_file);
1857 : 17 : print_decs (c->index, dump_file);
1858 : 17 : fputs (" * ", dump_file);
1859 : 17 : if (TREE_CODE (c->stride) != INTEGER_CST
1860 : 17 : && c->stride_type != TREE_TYPE (c->stride))
1861 : : {
1862 : 0 : fputs ("(", dump_file);
1863 : 0 : print_generic_expr (dump_file, c->stride_type);
1864 : 0 : fputs (")", dump_file);
1865 : : }
1866 : 17 : print_generic_expr (dump_file, c->stride);
1867 : 17 : fputs (") : ", dump_file);
1868 : 17 : break;
1869 : 11 : case CAND_REF:
1870 : 11 : fputs (" REF : ", dump_file);
1871 : 11 : print_generic_expr (dump_file, c->base_expr);
1872 : 11 : fputs (" + (", dump_file);
1873 : 11 : print_generic_expr (dump_file, c->stride);
1874 : 11 : fputs (") + ", dump_file);
1875 : 11 : print_decs (c->index, dump_file);
1876 : 11 : fputs (" : ", dump_file);
1877 : 11 : break;
1878 : 0 : case CAND_PHI:
1879 : 0 : fputs (" PHI : ", dump_file);
1880 : 0 : print_generic_expr (dump_file, c->base_expr);
1881 : 0 : fputs (" + (unknown * ", dump_file);
1882 : 0 : print_generic_expr (dump_file, c->stride);
1883 : 0 : fputs (") : ", dump_file);
1884 : 0 : break;
1885 : 0 : default:
1886 : 0 : gcc_unreachable ();
1887 : : }
1888 : 31 : print_generic_expr (dump_file, c->cand_type);
1889 : 31 : fprintf (dump_file, "\n basis: %d dependent: %d sibling: %d\n",
1890 : : c->basis, c->dependent, c->sibling);
1891 : 31 : fprintf (dump_file,
1892 : : " next-interp: %d first-interp: %d dead-savings: %d\n",
1893 : : c->next_interp, c->first_interp, c->dead_savings);
1894 : 31 : if (c->def_phi)
1895 : 0 : fprintf (dump_file, " phi: %d\n", c->def_phi);
1896 : 31 : fputs ("\n", dump_file);
1897 : 31 : }
1898 : :
1899 : : /* Dump the candidate vector for debug. */
1900 : :
1901 : : static void
1902 : 3 : dump_cand_vec (void)
1903 : : {
1904 : 3 : unsigned i;
1905 : 3 : slsr_cand_t c;
1906 : :
1907 : 3 : fprintf (dump_file, "\nStrength reduction candidate vector:\n\n");
1908 : :
1909 : 40 : FOR_EACH_VEC_ELT (cand_vec, i, c)
1910 : 34 : if (c != NULL)
1911 : 31 : dump_candidate (c);
1912 : 3 : }
1913 : :
1914 : : /* Callback used to dump the candidate chains hash table. */
1915 : :
1916 : : int
1917 : 15 : ssa_base_cand_dump_callback (cand_chain **slot, void *ignored ATTRIBUTE_UNUSED)
1918 : : {
1919 : 15 : const_cand_chain_t chain = *slot;
1920 : 15 : cand_chain_t p;
1921 : :
1922 : 15 : print_generic_expr (dump_file, chain->base_expr);
1923 : 15 : fprintf (dump_file, " -> %d", chain->cand->cand_num);
1924 : :
1925 : 40 : for (p = chain->next; p; p = p->next)
1926 : 25 : fprintf (dump_file, " -> %d", p->cand->cand_num);
1927 : :
1928 : 15 : fputs ("\n", dump_file);
1929 : 15 : return 1;
1930 : : }
1931 : :
1932 : : /* Dump the candidate chains. */
1933 : :
1934 : : static void
1935 : 3 : dump_cand_chains (void)
1936 : : {
1937 : 3 : fprintf (dump_file, "\nStrength reduction candidate chains:\n\n");
1938 : 3 : base_cand_map->traverse_noresize <void *, ssa_base_cand_dump_callback>
1939 : 3 : (NULL);
1940 : 3 : fputs ("\n", dump_file);
1941 : 3 : }
1942 : :
1943 : : /* Dump the increment vector for debug. */
1944 : :
1945 : : static void
1946 : 52013 : dump_incr_vec (void)
1947 : : {
1948 : 52013 : if (dump_file && (dump_flags & TDF_DETAILS))
1949 : : {
1950 : 0 : unsigned i;
1951 : :
1952 : 0 : fprintf (dump_file, "\nIncrement vector:\n\n");
1953 : :
1954 : 0 : for (i = 0; i < incr_vec_len; i++)
1955 : : {
1956 : 0 : fprintf (dump_file, "%3d increment: ", i);
1957 : 0 : print_decs (incr_vec[i].incr, dump_file);
1958 : 0 : fprintf (dump_file, "\n count: %d", incr_vec[i].count);
1959 : 0 : fprintf (dump_file, "\n cost: %d", incr_vec[i].cost);
1960 : 0 : fputs ("\n initializer: ", dump_file);
1961 : 0 : print_generic_expr (dump_file, incr_vec[i].initializer);
1962 : 0 : fputs ("\n\n", dump_file);
1963 : : }
1964 : : }
1965 : 52013 : }
1966 : :
1967 : : /* Replace *EXPR in candidate C with an equivalent strength-reduced
1968 : : data reference. */
1969 : :
1970 : : static void
1971 : 13226 : replace_ref (tree *expr, slsr_cand_t c)
1972 : : {
1973 : 13226 : tree add_expr, mem_ref, acc_type = TREE_TYPE (*expr);
1974 : 13226 : unsigned HOST_WIDE_INT misalign;
1975 : 13226 : unsigned align;
1976 : :
1977 : : /* Ensure the memory reference carries the minimum alignment
1978 : : requirement for the data type. See PR58041. */
1979 : 13226 : get_object_alignment_1 (*expr, &align, &misalign);
1980 : 13226 : if (misalign != 0)
1981 : 257 : align = least_bit_hwi (misalign);
1982 : 13226 : if (align < TYPE_ALIGN (acc_type))
1983 : 14 : acc_type = build_aligned_type (acc_type, align);
1984 : :
1985 : 13226 : add_expr = fold_build2 (POINTER_PLUS_EXPR, c->cand_type,
1986 : : c->base_expr, c->stride);
1987 : 13226 : mem_ref = fold_build2 (MEM_REF, acc_type, add_expr,
1988 : : wide_int_to_tree (c->cand_type, c->index));
1989 : :
1990 : : /* Gimplify the base addressing expression for the new MEM_REF tree. */
1991 : 13226 : gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt);
1992 : 13226 : TREE_OPERAND (mem_ref, 0)
1993 : 13226 : = force_gimple_operand_gsi (&gsi, TREE_OPERAND (mem_ref, 0),
1994 : : /*simple_p=*/true, NULL,
1995 : : /*before=*/true, GSI_SAME_STMT);
1996 : 13226 : copy_ref_info (mem_ref, *expr);
1997 : 13226 : *expr = mem_ref;
1998 : 13226 : update_stmt (c->cand_stmt);
1999 : 13226 : }
2000 : :
2001 : : /* Return true if CAND_REF candidate C is a valid memory reference. */
2002 : :
2003 : : static bool
2004 : 5589 : valid_mem_ref_cand_p (slsr_cand_t c)
2005 : : {
2006 : 5589 : if (TREE_CODE (TREE_OPERAND (c->stride, 1)) != INTEGER_CST)
2007 : : return false;
2008 : :
2009 : 5589 : struct mem_address addr
2010 : 11178 : = { NULL_TREE, c->base_expr, TREE_OPERAND (c->stride, 0),
2011 : 5589 : TREE_OPERAND (c->stride, 1), wide_int_to_tree (sizetype, c->index) };
2012 : :
2013 : 5589 : return
2014 : 5589 : valid_mem_ref_p (TYPE_MODE (c->cand_type), TYPE_ADDR_SPACE (c->cand_type),
2015 : : &addr);
2016 : : }
2017 : :
2018 : : /* Replace CAND_REF candidate C, each sibling of candidate C, and each
2019 : : dependent of candidate C with an equivalent strength-reduced data
2020 : : reference. */
2021 : :
2022 : : static void
2023 : 5819 : replace_refs (slsr_cand_t c)
2024 : : {
2025 : : /* Replacing a chain of only 2 candidates which are valid memory references
2026 : : is generally counter-productive because you cannot recoup the additional
2027 : : calculation added in front of them. */
2028 : 15814 : if (c->basis == 0
2029 : 5397 : && c->dependent
2030 : 5397 : && !lookup_cand (c->dependent)->dependent
2031 : 3001 : && valid_mem_ref_cand_p (c)
2032 : 18402 : && valid_mem_ref_cand_p (lookup_cand (c->dependent)))
2033 : : return;
2034 : :
2035 : 13226 : if (dump_file && (dump_flags & TDF_DETAILS))
2036 : : {
2037 : 9 : fputs ("Replacing reference: ", dump_file);
2038 : 9 : print_gimple_stmt (dump_file, c->cand_stmt, 0);
2039 : : }
2040 : :
2041 : 26452 : if (gimple_vdef (c->cand_stmt))
2042 : : {
2043 : 4852 : tree *lhs = gimple_assign_lhs_ptr (c->cand_stmt);
2044 : 4852 : replace_ref (lhs, c);
2045 : : }
2046 : : else
2047 : : {
2048 : 8374 : tree *rhs = gimple_assign_rhs1_ptr (c->cand_stmt);
2049 : 8374 : replace_ref (rhs, c);
2050 : : }
2051 : :
2052 : 13226 : if (dump_file && (dump_flags & TDF_DETAILS))
2053 : : {
2054 : 9 : fputs ("With: ", dump_file);
2055 : 9 : print_gimple_stmt (dump_file, c->cand_stmt, 0);
2056 : 9 : fputs ("\n", dump_file);
2057 : : }
2058 : :
2059 : 13226 : if (c->sibling)
2060 : 422 : replace_refs (lookup_cand (c->sibling));
2061 : :
2062 : 13226 : if (c->dependent)
2063 : 9995 : replace_refs (lookup_cand (c->dependent));
2064 : : }
2065 : :
2066 : : /* Return TRUE if candidate C is dependent upon a PHI. */
2067 : :
2068 : : static bool
2069 : 2317312 : phi_dependent_cand_p (slsr_cand_t c)
2070 : : {
2071 : : /* A candidate is not necessarily dependent upon a PHI just because
2072 : : it has a phi definition for its base name. It may have a basis
2073 : : that relies upon the same phi definition, in which case the PHI
2074 : : is irrelevant to this candidate. */
2075 : 2317312 : return (c->def_phi
2076 : 216 : && c->basis
2077 : 2317528 : && lookup_cand (c->basis)->def_phi != c->def_phi);
2078 : : }
2079 : :
2080 : : /* Calculate the increment required for candidate C relative to
2081 : : its basis. */
2082 : :
2083 : : static offset_int
2084 : 1231280 : cand_increment (slsr_cand_t c)
2085 : : {
2086 : 1231280 : slsr_cand_t basis;
2087 : :
2088 : : /* If the candidate doesn't have a basis, just return its own
2089 : : index. This is useful in record_increments to help us find
2090 : : an existing initializer. Also, if the candidate's basis is
2091 : : hidden by a phi, then its own index will be the increment
2092 : : from the newly introduced phi basis. */
2093 : 1231280 : if (!c->basis || phi_dependent_cand_p (c))
2094 : 52056 : return c->index;
2095 : :
2096 : 1179224 : basis = lookup_cand (c->basis);
2097 : 1179224 : gcc_assert (operand_equal_p (c->base_expr, basis->base_expr, 0));
2098 : 1179224 : return c->index - basis->index;
2099 : : }
2100 : :
2101 : : /* Calculate the increment required for candidate C relative to
2102 : : its basis. If we aren't going to generate pointer arithmetic
2103 : : for this candidate, return the absolute value of that increment
2104 : : instead. */
2105 : :
2106 : : static inline offset_int
2107 : 94903 : cand_abs_increment (slsr_cand_t c)
2108 : : {
2109 : 94903 : offset_int increment = cand_increment (c);
2110 : :
2111 : 94903 : if (!address_arithmetic_p && wi::neg_p (increment))
2112 : 1902 : increment = -increment;
2113 : :
2114 : 94903 : return increment;
2115 : : }
2116 : :
2117 : : /* Return TRUE iff candidate C has already been replaced under
2118 : : another interpretation. */
2119 : :
2120 : : static inline bool
2121 : 1401345 : cand_already_replaced (slsr_cand_t c)
2122 : : {
2123 : 682 : return (gimple_bb (c->cand_stmt) == 0);
2124 : : }
2125 : :
2126 : : /* Common logic used by replace_unconditional_candidate and
2127 : : replace_conditional_candidate. */
2128 : :
2129 : : static void
2130 : 972510 : replace_mult_candidate (slsr_cand_t c, tree basis_name, offset_int bump,
2131 : : auto_bitmap &sdce_worklist)
2132 : : {
2133 : 972510 : tree target_type = TREE_TYPE (gimple_assign_lhs (c->cand_stmt));
2134 : 972510 : enum tree_code cand_code = gimple_assign_rhs_code (c->cand_stmt);
2135 : :
2136 : : /* It is not useful to replace casts, copies, negates, or adds of
2137 : : an SSA name and a constant. */
2138 : 972510 : if (cand_code == SSA_NAME
2139 : : || CONVERT_EXPR_CODE_P (cand_code)
2140 : : || cand_code == PLUS_EXPR
2141 : : || cand_code == POINTER_PLUS_EXPR
2142 : : || cand_code == MINUS_EXPR
2143 : : || cand_code == NEGATE_EXPR)
2144 : : return;
2145 : :
2146 : 69329 : enum tree_code code = PLUS_EXPR;
2147 : 69329 : tree bump_tree;
2148 : 69329 : gimple *stmt_to_print = NULL;
2149 : :
2150 : 69329 : if (wi::neg_p (bump))
2151 : : {
2152 : 5919 : code = MINUS_EXPR;
2153 : 5919 : bump = -bump;
2154 : : }
2155 : :
2156 : : /* It is possible that the resulting bump doesn't fit in target_type.
2157 : : Abandon the replacement in this case. This does not affect
2158 : : siblings or dependents of C. */
2159 : 69329 : if (bump != wi::ext (bump, TYPE_PRECISION (target_type),
2160 : 69329 : TYPE_SIGN (target_type)))
2161 : : return;
2162 : :
2163 : 68677 : bump_tree = wide_int_to_tree (target_type, bump);
2164 : :
2165 : : /* If the basis name and the candidate's LHS have incompatible types,
2166 : : introduce a cast. */
2167 : 68677 : if (!useless_type_conversion_p (target_type, TREE_TYPE (basis_name)))
2168 : 0 : basis_name = introduce_cast_before_cand (c, target_type, basis_name);
2169 : :
2170 : 68677 : if (dump_file && (dump_flags & TDF_DETAILS))
2171 : : {
2172 : 0 : fputs ("Replacing: ", dump_file);
2173 : 0 : print_gimple_stmt (dump_file, c->cand_stmt, 0);
2174 : : }
2175 : :
2176 : 68677 : if (bump == 0)
2177 : : {
2178 : 50839 : tree lhs = gimple_assign_lhs (c->cand_stmt);
2179 : 50839 : gassign *copy_stmt = gimple_build_assign (lhs, basis_name);
2180 : 50839 : gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt);
2181 : 50839 : slsr_cand_t cc = lookup_cand (c->first_interp);
2182 : 50839 : gimple_set_location (copy_stmt, gimple_location (c->cand_stmt));
2183 : 50839 : gsi_replace (&gsi, copy_stmt, false);
2184 : 152517 : while (cc)
2185 : : {
2186 : 50839 : cc->cand_stmt = copy_stmt;
2187 : 50839 : cc = lookup_cand (cc->next_interp);
2188 : : }
2189 : 50839 : if (dump_file && (dump_flags & TDF_DETAILS))
2190 : : stmt_to_print = copy_stmt;
2191 : : }
2192 : : else
2193 : : {
2194 : 17838 : tree rhs1, rhs2;
2195 : 17838 : if (cand_code != NEGATE_EXPR) {
2196 : 17838 : rhs1 = gimple_assign_rhs1 (c->cand_stmt);
2197 : 17838 : rhs2 = gimple_assign_rhs2 (c->cand_stmt);
2198 : : /* Mark the 2 original rhs for maybe DCEing. */
2199 : 17838 : if (TREE_CODE (rhs1) == SSA_NAME)
2200 : 17838 : bitmap_set_bit (sdce_worklist, SSA_NAME_VERSION (rhs1));
2201 : 17838 : if (TREE_CODE (rhs2) == SSA_NAME)
2202 : 0 : bitmap_set_bit (sdce_worklist, SSA_NAME_VERSION (rhs2));
2203 : : }
2204 : 17838 : if (cand_code != NEGATE_EXPR
2205 : 17838 : && ((operand_equal_p (rhs1, basis_name, 0)
2206 : 0 : && operand_equal_p (rhs2, bump_tree, 0))
2207 : 17838 : || (operand_equal_p (rhs1, bump_tree, 0)
2208 : 0 : && operand_equal_p (rhs2, basis_name, 0))))
2209 : : {
2210 : 0 : if (dump_file && (dump_flags & TDF_DETAILS))
2211 : : {
2212 : 0 : fputs ("(duplicate, not actually replacing)", dump_file);
2213 : 0 : stmt_to_print = c->cand_stmt;
2214 : : }
2215 : : }
2216 : : else
2217 : : {
2218 : 17838 : gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt);
2219 : 17838 : slsr_cand_t cc = lookup_cand (c->first_interp);
2220 : 17838 : gimple_assign_set_rhs_with_ops (&gsi, code, basis_name, bump_tree);
2221 : 17838 : update_stmt (gsi_stmt (gsi));
2222 : 53514 : while (cc)
2223 : : {
2224 : 17838 : cc->cand_stmt = gsi_stmt (gsi);
2225 : 17838 : cc = lookup_cand (cc->next_interp);
2226 : : }
2227 : 17838 : if (dump_file && (dump_flags & TDF_DETAILS))
2228 : 0 : stmt_to_print = gsi_stmt (gsi);
2229 : : }
2230 : : }
2231 : :
2232 : 68677 : if (dump_file && (dump_flags & TDF_DETAILS))
2233 : : {
2234 : 0 : fputs ("With: ", dump_file);
2235 : 0 : print_gimple_stmt (dump_file, stmt_to_print, 0);
2236 : 0 : fputs ("\n", dump_file);
2237 : : }
2238 : : }
2239 : :
2240 : : /* Replace candidate C with an add or subtract. Note that we only
2241 : : operate on CAND_MULTs with known strides, so we will never generate
2242 : : a POINTER_PLUS_EXPR. Each candidate X = (B + i) * S is replaced by
2243 : : X = Y + ((i - i') * S), as described in the module commentary. The
2244 : : folded value ((i - i') * S) is referred to here as the "bump." */
2245 : :
2246 : : static void
2247 : 972495 : replace_unconditional_candidate (slsr_cand_t c, auto_bitmap &sdce_worklist)
2248 : : {
2249 : 972495 : slsr_cand_t basis;
2250 : :
2251 : 972495 : if (cand_already_replaced (c))
2252 : 0 : return;
2253 : :
2254 : 972495 : basis = lookup_cand (c->basis);
2255 : 972495 : offset_int bump = cand_increment (c) * wi::to_offset (c->stride);
2256 : :
2257 : 972495 : replace_mult_candidate (c, gimple_assign_lhs (basis->cand_stmt), bump,
2258 : : sdce_worklist);
2259 : : }
2260 : :
2261 : : /* Return the index in the increment vector of the given INCREMENT,
2262 : : or -1 if not found. The latter can occur if more than
2263 : : MAX_INCR_VEC_LEN increments have been found. */
2264 : :
2265 : : static inline int
2266 : 89358 : incr_vec_index (const offset_int &increment)
2267 : : {
2268 : 89358 : unsigned i;
2269 : :
2270 : 163048 : for (i = 0; i < incr_vec_len && increment != incr_vec[i].incr; i++)
2271 : : ;
2272 : :
2273 : 89358 : if (i < incr_vec_len)
2274 : 89358 : return i;
2275 : : else
2276 : : return -1;
2277 : : }
2278 : :
2279 : : /* Create a new statement along edge E to add BASIS_NAME to the product
2280 : : of INCREMENT and the stride of candidate C. Create and return a new
2281 : : SSA name from *VAR to be used as the LHS of the new statement.
2282 : : KNOWN_STRIDE is true iff C's stride is a constant. */
2283 : :
2284 : : static tree
2285 : 29 : create_add_on_incoming_edge (slsr_cand_t c, tree basis_name,
2286 : : offset_int increment, edge e, location_t loc,
2287 : : bool known_stride)
2288 : : {
2289 : 29 : tree lhs, basis_type;
2290 : 29 : gassign *new_stmt, *cast_stmt = NULL;
2291 : :
2292 : : /* If the add candidate along this incoming edge has the same
2293 : : index as C's hidden basis, the hidden basis represents this
2294 : : edge correctly. */
2295 : 29 : if (increment == 0)
2296 : : return basis_name;
2297 : :
2298 : 25 : basis_type = TREE_TYPE (basis_name);
2299 : 25 : lhs = make_temp_ssa_name (basis_type, NULL, "slsr");
2300 : :
2301 : : /* Occasionally people convert integers to pointers without a
2302 : : cast, leading us into trouble if we aren't careful. */
2303 : 50 : enum tree_code plus_code
2304 : 25 : = POINTER_TYPE_P (basis_type) ? POINTER_PLUS_EXPR : PLUS_EXPR;
2305 : :
2306 : 25 : if (known_stride)
2307 : : {
2308 : 17 : tree bump_tree;
2309 : 17 : enum tree_code code = plus_code;
2310 : 17 : offset_int bump = increment * wi::to_offset (c->stride);
2311 : 17 : if (wi::neg_p (bump) && !POINTER_TYPE_P (basis_type))
2312 : : {
2313 : 1 : code = MINUS_EXPR;
2314 : 1 : bump = -bump;
2315 : : }
2316 : :
2317 : 17 : tree stride_type = POINTER_TYPE_P (basis_type) ? sizetype : basis_type;
2318 : 17 : bump_tree = wide_int_to_tree (stride_type, bump);
2319 : 17 : new_stmt = gimple_build_assign (lhs, code, basis_name, bump_tree);
2320 : : }
2321 : : else
2322 : : {
2323 : 8 : int i;
2324 : 8 : bool negate_incr = !POINTER_TYPE_P (basis_type) && wi::neg_p (increment);
2325 : 8 : i = incr_vec_index (negate_incr ? -increment : increment);
2326 : 8 : gcc_assert (i >= 0);
2327 : :
2328 : 8 : if (incr_vec[i].initializer)
2329 : : {
2330 : 8 : enum tree_code code = negate_incr ? MINUS_EXPR : plus_code;
2331 : 8 : new_stmt = gimple_build_assign (lhs, code, basis_name,
2332 : : incr_vec[i].initializer);
2333 : : }
2334 : : else {
2335 : 0 : tree stride;
2336 : :
2337 : 0 : if (!types_compatible_p (TREE_TYPE (c->stride), c->stride_type))
2338 : : {
2339 : 0 : tree cast_stride = make_temp_ssa_name (c->stride_type, NULL,
2340 : : "slsr");
2341 : 0 : cast_stmt = gimple_build_assign (cast_stride, NOP_EXPR,
2342 : : c->stride);
2343 : 0 : stride = cast_stride;
2344 : : }
2345 : : else
2346 : 0 : stride = c->stride;
2347 : :
2348 : 0 : if (increment == 1)
2349 : 0 : new_stmt = gimple_build_assign (lhs, plus_code, basis_name, stride);
2350 : 0 : else if (increment == -1)
2351 : 0 : new_stmt = gimple_build_assign (lhs, MINUS_EXPR, basis_name, stride);
2352 : : else
2353 : 0 : gcc_unreachable ();
2354 : : }
2355 : : }
2356 : :
2357 : 25 : if (cast_stmt)
2358 : : {
2359 : 0 : gimple_set_location (cast_stmt, loc);
2360 : 0 : gsi_insert_on_edge (e, cast_stmt);
2361 : : }
2362 : :
2363 : 25 : gimple_set_location (new_stmt, loc);
2364 : 25 : gsi_insert_on_edge (e, new_stmt);
2365 : :
2366 : 25 : if (dump_file && (dump_flags & TDF_DETAILS))
2367 : : {
2368 : 0 : if (cast_stmt)
2369 : : {
2370 : 0 : fprintf (dump_file, "Inserting cast on edge %d->%d: ",
2371 : 0 : e->src->index, e->dest->index);
2372 : 0 : print_gimple_stmt (dump_file, cast_stmt, 0);
2373 : : }
2374 : 0 : fprintf (dump_file, "Inserting on edge %d->%d: ", e->src->index,
2375 : 0 : e->dest->index);
2376 : 0 : print_gimple_stmt (dump_file, new_stmt, 0);
2377 : : }
2378 : :
2379 : : return lhs;
2380 : : }
2381 : :
2382 : : /* Clear the visited field for a tree of PHI candidates. */
2383 : :
2384 : : static void
2385 : 91 : clear_visited (gphi *phi)
2386 : : {
2387 : 91 : unsigned i;
2388 : 91 : slsr_cand_t phi_cand = *stmt_cand_map->get (phi);
2389 : :
2390 : 91 : if (phi_cand->visited)
2391 : : {
2392 : 91 : phi_cand->visited = 0;
2393 : :
2394 : 259 : for (i = 0; i < gimple_phi_num_args (phi); i++)
2395 : : {
2396 : 168 : tree arg = gimple_phi_arg_def (phi, i);
2397 : 168 : gimple *arg_def = SSA_NAME_DEF_STMT (arg);
2398 : 168 : if (gimple_code (arg_def) == GIMPLE_PHI)
2399 : 2 : clear_visited (as_a <gphi *> (arg_def));
2400 : : }
2401 : : }
2402 : 91 : }
2403 : :
2404 : : /* Recursive helper function for create_phi_basis. */
2405 : :
2406 : : static tree
2407 : 24 : create_phi_basis_1 (slsr_cand_t c, gimple *from_phi, tree basis_name,
2408 : : location_t loc, bool known_stride)
2409 : : {
2410 : 24 : int i;
2411 : 24 : tree name, phi_arg;
2412 : 24 : gphi *phi;
2413 : 24 : slsr_cand_t basis = lookup_cand (c->basis);
2414 : 24 : int nargs = gimple_phi_num_args (from_phi);
2415 : 24 : basic_block phi_bb = gimple_bb (from_phi);
2416 : 24 : slsr_cand_t phi_cand = *stmt_cand_map->get (from_phi);
2417 : 24 : auto_vec<tree> phi_args (nargs);
2418 : :
2419 : 24 : if (phi_cand->visited)
2420 : 0 : return phi_cand->cached_basis;
2421 : 24 : phi_cand->visited = 1;
2422 : :
2423 : : /* Process each argument of the existing phi that represents
2424 : : conditionally-executed add candidates. */
2425 : 61 : for (i = 0; i < nargs; i++)
2426 : : {
2427 : 37 : edge e = (*phi_bb->preds)[i];
2428 : 37 : tree arg = gimple_phi_arg_def (from_phi, i);
2429 : 37 : tree feeding_def;
2430 : :
2431 : : /* If the phi argument is the base name of the CAND_PHI, then
2432 : : this incoming arc should use the hidden basis. */
2433 : 37 : if (operand_equal_p (arg, phi_cand->base_expr, 0))
2434 : 7 : if (basis->index == 0)
2435 : 7 : feeding_def = gimple_assign_lhs (basis->cand_stmt);
2436 : : else
2437 : : {
2438 : 0 : offset_int incr = -basis->index;
2439 : 0 : feeding_def = create_add_on_incoming_edge (c, basis_name, incr,
2440 : : e, loc, known_stride);
2441 : : }
2442 : : else
2443 : : {
2444 : 30 : gimple *arg_def = SSA_NAME_DEF_STMT (arg);
2445 : :
2446 : : /* If there is another phi along this incoming edge, we must
2447 : : process it in the same fashion to ensure that all basis
2448 : : adjustments are made along its incoming edges. */
2449 : 30 : if (gimple_code (arg_def) == GIMPLE_PHI)
2450 : 1 : feeding_def = create_phi_basis_1 (c, arg_def, basis_name,
2451 : : loc, known_stride);
2452 : : else
2453 : : {
2454 : 29 : slsr_cand_t arg_cand = base_cand_from_table (arg);
2455 : 29 : offset_int diff = arg_cand->index - basis->index;
2456 : 29 : feeding_def = create_add_on_incoming_edge (c, basis_name, diff,
2457 : : e, loc, known_stride);
2458 : : }
2459 : : }
2460 : :
2461 : : /* Because of recursion, we need to save the arguments in a vector
2462 : : so we can create the PHI statement all at once. Otherwise the
2463 : : storage for the half-created PHI can be reclaimed. */
2464 : 37 : phi_args.safe_push (feeding_def);
2465 : : }
2466 : :
2467 : : /* Create the new phi basis. */
2468 : 24 : name = make_temp_ssa_name (TREE_TYPE (basis_name), NULL, "slsr");
2469 : 24 : phi = create_phi_node (name, phi_bb);
2470 : 24 : SSA_NAME_DEF_STMT (name) = phi;
2471 : :
2472 : 61 : FOR_EACH_VEC_ELT (phi_args, i, phi_arg)
2473 : : {
2474 : 37 : edge e = (*phi_bb->preds)[i];
2475 : 37 : add_phi_arg (phi, phi_arg, e, loc);
2476 : : }
2477 : :
2478 : 24 : update_stmt (phi);
2479 : :
2480 : 24 : if (dump_file && (dump_flags & TDF_DETAILS))
2481 : : {
2482 : 0 : fputs ("Introducing new phi basis: ", dump_file);
2483 : 0 : print_gimple_stmt (dump_file, phi, 0);
2484 : : }
2485 : :
2486 : 24 : phi_cand->cached_basis = name;
2487 : 24 : return name;
2488 : 24 : }
2489 : :
2490 : : /* Given a candidate C with BASIS_NAME being the LHS of C's basis which
2491 : : is hidden by the phi node FROM_PHI, create a new phi node in the same
2492 : : block as FROM_PHI. The new phi is suitable for use as a basis by C,
2493 : : with its phi arguments representing conditional adjustments to the
2494 : : hidden basis along conditional incoming paths. Those adjustments are
2495 : : made by creating add statements (and sometimes recursively creating
2496 : : phis) along those incoming paths. LOC is the location to attach to
2497 : : the introduced statements. KNOWN_STRIDE is true iff C's stride is a
2498 : : constant. */
2499 : :
2500 : : static tree
2501 : 23 : create_phi_basis (slsr_cand_t c, gimple *from_phi, tree basis_name,
2502 : : location_t loc, bool known_stride)
2503 : : {
2504 : 23 : tree retval = create_phi_basis_1 (c, from_phi, basis_name, loc,
2505 : : known_stride);
2506 : 23 : gcc_assert (retval);
2507 : 23 : clear_visited (as_a <gphi *> (from_phi));
2508 : 23 : return retval;
2509 : : }
2510 : :
2511 : : /* Given a candidate C whose basis is hidden by at least one intervening
2512 : : phi, introduce a matching number of new phis to represent its basis
2513 : : adjusted by conditional increments along possible incoming paths. Then
2514 : : replace C as though it were an unconditional candidate, using the new
2515 : : basis. */
2516 : :
2517 : : static void
2518 : 15 : replace_conditional_candidate (slsr_cand_t c, auto_bitmap &sdce_worklist)
2519 : :
2520 : : {
2521 : 15 : tree basis_name, name;
2522 : 15 : slsr_cand_t basis;
2523 : 15 : location_t loc;
2524 : :
2525 : : /* Look up the LHS SSA name from C's basis. This will be the
2526 : : RHS1 of the adds we will introduce to create new phi arguments. */
2527 : 15 : basis = lookup_cand (c->basis);
2528 : 15 : basis_name = gimple_assign_lhs (basis->cand_stmt);
2529 : :
2530 : : /* Create a new phi statement which will represent C's true basis
2531 : : after the transformation is complete. */
2532 : 15 : loc = gimple_location (c->cand_stmt);
2533 : 15 : name = create_phi_basis (c, lookup_cand (c->def_phi)->cand_stmt,
2534 : : basis_name, loc, KNOWN_STRIDE);
2535 : :
2536 : : /* Replace C with an add of the new basis phi and a constant. */
2537 : 15 : offset_int bump = c->index * wi::to_offset (c->stride);
2538 : :
2539 : 15 : replace_mult_candidate (c, name, bump, sdce_worklist);
2540 : 15 : }
2541 : :
2542 : : /* Recursive helper function for phi_add_costs. SPREAD is a measure of
2543 : : how many PHI nodes we have visited at this point in the tree walk. */
2544 : :
2545 : : static int
2546 : 28 : phi_add_costs_1 (gimple *phi, slsr_cand_t c, int one_add_cost, int *spread)
2547 : : {
2548 : 28 : unsigned i;
2549 : 28 : int cost = 0;
2550 : 28 : slsr_cand_t phi_cand = *stmt_cand_map->get (phi);
2551 : :
2552 : 28 : if (phi_cand->visited)
2553 : : return 0;
2554 : :
2555 : 28 : phi_cand->visited = 1;
2556 : 28 : (*spread)++;
2557 : :
2558 : : /* If we work our way back to a phi that isn't dominated by the hidden
2559 : : basis, this isn't a candidate for replacement. Indicate this by
2560 : : returning an unreasonably high cost. It's not easy to detect
2561 : : these situations when determining the basis, so we defer the
2562 : : decision until now. */
2563 : 28 : basic_block phi_bb = gimple_bb (phi);
2564 : 28 : slsr_cand_t basis = lookup_cand (c->basis);
2565 : 28 : basic_block basis_bb = gimple_bb (basis->cand_stmt);
2566 : :
2567 : 28 : if (phi_bb == basis_bb || !dominated_by_p (CDI_DOMINATORS, phi_bb, basis_bb))
2568 : 0 : return COST_INFINITE;
2569 : :
2570 : 81 : for (i = 0; i < gimple_phi_num_args (phi); i++)
2571 : : {
2572 : 53 : tree arg = gimple_phi_arg_def (phi, i);
2573 : :
2574 : 53 : if (arg != phi_cand->base_expr)
2575 : : {
2576 : 52 : gimple *arg_def = SSA_NAME_DEF_STMT (arg);
2577 : :
2578 : 52 : if (gimple_code (arg_def) == GIMPLE_PHI)
2579 : : {
2580 : 1 : cost += phi_add_costs_1 (arg_def, c, one_add_cost, spread);
2581 : :
2582 : 1 : if (cost >= COST_INFINITE || *spread > MAX_SPREAD)
2583 : : return COST_INFINITE;
2584 : : }
2585 : : else
2586 : : {
2587 : 51 : slsr_cand_t arg_cand = base_cand_from_table (arg);
2588 : :
2589 : 51 : if (arg_cand->index != c->index)
2590 : 48 : cost += one_add_cost;
2591 : : }
2592 : : }
2593 : : }
2594 : :
2595 : : return cost;
2596 : : }
2597 : :
2598 : : /* Compute the expected costs of inserting basis adjustments for
2599 : : candidate C with phi-definition PHI. The cost of inserting
2600 : : one adjustment is given by ONE_ADD_COST. If PHI has arguments
2601 : : which are themselves phi results, recursively calculate costs
2602 : : for those phis as well. */
2603 : :
2604 : : static int
2605 : 27 : phi_add_costs (gimple *phi, slsr_cand_t c, int one_add_cost)
2606 : : {
2607 : 27 : int spread = 0;
2608 : 27 : int retval = phi_add_costs_1 (phi, c, one_add_cost, &spread);
2609 : 27 : clear_visited (as_a <gphi *> (phi));
2610 : 27 : return retval;
2611 : : }
2612 : : /* For candidate C, each sibling of candidate C, and each dependent of
2613 : : candidate C, determine whether the candidate is dependent upon a
2614 : : phi that hides its basis. If not, replace the candidate unconditionally.
2615 : : Otherwise, determine whether the cost of introducing compensation code
2616 : : for the candidate is offset by the gains from strength reduction. If
2617 : : so, replace the candidate and introduce the compensation code. */
2618 : :
2619 : : static void
2620 : 493256 : replace_uncond_cands_and_profitable_phis (slsr_cand_t c,
2621 : : auto_bitmap &sdce_worklist)
2622 : : {
2623 : 972553 : if (phi_dependent_cand_p (c))
2624 : : {
2625 : : /* A multiply candidate with a stride of 1 is just an artifice
2626 : : of a copy or cast; there is no value in replacing it. */
2627 : 58 : if (c->kind == CAND_MULT && wi::to_offset (c->stride) != 1)
2628 : : {
2629 : : /* A candidate dependent upon a phi will replace a multiply by
2630 : : a constant with an add, and will insert at most one add for
2631 : : each phi argument. Add these costs with the potential dead-code
2632 : : savings to determine profitability. */
2633 : 27 : bool speed = optimize_bb_for_speed_p (gimple_bb (c->cand_stmt));
2634 : 27 : int mult_savings = stmt_cost (c->cand_stmt, speed);
2635 : 27 : gimple *phi = lookup_cand (c->def_phi)->cand_stmt;
2636 : 27 : tree phi_result = gimple_phi_result (phi);
2637 : 108 : int one_add_cost = add_cost (speed,
2638 : 27 : TYPE_MODE (TREE_TYPE (phi_result)));
2639 : 27 : int add_costs = one_add_cost + phi_add_costs (phi, c, one_add_cost);
2640 : 27 : int cost = add_costs - mult_savings - c->dead_savings;
2641 : :
2642 : 27 : if (dump_file && (dump_flags & TDF_DETAILS))
2643 : : {
2644 : 0 : fprintf (dump_file, " Conditional candidate %d:\n", c->cand_num);
2645 : 0 : fprintf (dump_file, " add_costs = %d\n", add_costs);
2646 : 0 : fprintf (dump_file, " mult_savings = %d\n", mult_savings);
2647 : 0 : fprintf (dump_file, " dead_savings = %d\n", c->dead_savings);
2648 : 0 : fprintf (dump_file, " cost = %d\n", cost);
2649 : 0 : if (cost <= COST_NEUTRAL)
2650 : 0 : fputs (" Replacing...\n", dump_file);
2651 : : else
2652 : 0 : fputs (" Not replaced.\n", dump_file);
2653 : : }
2654 : :
2655 : 27 : if (cost <= COST_NEUTRAL)
2656 : 15 : replace_conditional_candidate (c, sdce_worklist);
2657 : : }
2658 : : }
2659 : : else
2660 : 972495 : replace_unconditional_candidate (c, sdce_worklist);
2661 : :
2662 : 972553 : if (c->sibling)
2663 : 35008 : replace_uncond_cands_and_profitable_phis (lookup_cand (c->sibling),
2664 : : sdce_worklist);
2665 : :
2666 : 972553 : if (c->dependent)
2667 : 479297 : replace_uncond_cands_and_profitable_phis (lookup_cand (c->dependent),
2668 : : sdce_worklist);
2669 : 493256 : }
2670 : :
2671 : : /* Count the number of candidates in the tree rooted at C that have
2672 : : not already been replaced under other interpretations. */
2673 : :
2674 : : static int
2675 : 54495 : count_candidates (slsr_cand_t c)
2676 : : {
2677 : 141342 : unsigned count = cand_already_replaced (c) ? 0 : 1;
2678 : :
2679 : 141342 : if (c->sibling)
2680 : 2482 : count += count_candidates (lookup_cand (c->sibling));
2681 : :
2682 : 141342 : if (c->dependent)
2683 : 86847 : count += count_candidates (lookup_cand (c->dependent));
2684 : :
2685 : 54495 : return count;
2686 : : }
2687 : :
2688 : : /* Increase the count of INCREMENT by one in the increment vector.
2689 : : INCREMENT is associated with candidate C. If INCREMENT is to be
2690 : : conditionally executed as part of a conditional candidate replacement,
2691 : : IS_PHI_ADJUST is true, otherwise false. If an initializer
2692 : : T_0 = stride * I is provided by a candidate that dominates all
2693 : : candidates with the same increment, also record T_0 for subsequent use. */
2694 : :
2695 : : static void
2696 : 141366 : record_increment (slsr_cand_t c, offset_int increment, bool is_phi_adjust)
2697 : : {
2698 : 141366 : bool found = false;
2699 : 141366 : unsigned i;
2700 : :
2701 : : /* Treat increments that differ only in sign as identical so as to
2702 : : share initializers, unless we are generating pointer arithmetic. */
2703 : 141366 : if (!address_arithmetic_p && wi::neg_p (increment))
2704 : 4703 : increment = -increment;
2705 : :
2706 : 215049 : for (i = 0; i < incr_vec_len; i++)
2707 : : {
2708 : 117423 : if (incr_vec[i].incr == increment)
2709 : : {
2710 : 43740 : incr_vec[i].count++;
2711 : 43740 : found = true;
2712 : :
2713 : : /* If we previously recorded an initializer that doesn't
2714 : : dominate this candidate, it's not going to be useful to
2715 : : us after all. */
2716 : 43740 : if (incr_vec[i].initializer
2717 : 43740 : && !dominated_by_p (CDI_DOMINATORS,
2718 : 891 : gimple_bb (c->cand_stmt),
2719 : 891 : incr_vec[i].init_bb))
2720 : : {
2721 : 0 : incr_vec[i].initializer = NULL_TREE;
2722 : 0 : incr_vec[i].init_bb = NULL;
2723 : : }
2724 : :
2725 : : break;
2726 : : }
2727 : : }
2728 : :
2729 : 97626 : if (!found && incr_vec_len < MAX_INCR_VEC_LEN - 1)
2730 : : {
2731 : : /* The first time we see an increment, create the entry for it.
2732 : : If this is the root candidate which doesn't have a basis, set
2733 : : the count to zero. We're only processing it so it can possibly
2734 : : provide an initializer for other candidates. */
2735 : 97626 : incr_vec[incr_vec_len].incr = increment;
2736 : 97626 : incr_vec[incr_vec_len].count = c->basis || is_phi_adjust ? 1 : 0;
2737 : 97626 : incr_vec[incr_vec_len].cost = COST_INFINITE;
2738 : :
2739 : : /* Optimistically record the first occurrence of this increment
2740 : : as providing an initializer (if it does); we will revise this
2741 : : opinion later if it doesn't dominate all other occurrences.
2742 : : Exception: increments of 0, 1 never need initializers;
2743 : : and phi adjustments don't ever provide initializers. */
2744 : 97626 : if (c->kind == CAND_ADD
2745 : 86595 : && !is_phi_adjust
2746 : 86583 : && c->index == increment
2747 : 40211 : && (increment > 1 || increment < 0)
2748 : 109943 : && (gimple_assign_rhs_code (c->cand_stmt) == PLUS_EXPR
2749 : 3808 : || gimple_assign_rhs_code (c->cand_stmt) == POINTER_PLUS_EXPR))
2750 : : {
2751 : 11223 : tree t0 = NULL_TREE;
2752 : 11223 : tree rhs1 = gimple_assign_rhs1 (c->cand_stmt);
2753 : 11223 : tree rhs2 = gimple_assign_rhs2 (c->cand_stmt);
2754 : 11223 : if (operand_equal_p (rhs1, c->base_expr, 0))
2755 : : t0 = rhs2;
2756 : 6894 : else if (operand_equal_p (rhs2, c->base_expr, 0))
2757 : : t0 = rhs1;
2758 : 11217 : if (t0
2759 : 11217 : && SSA_NAME_DEF_STMT (t0)
2760 : 22434 : && gimple_bb (SSA_NAME_DEF_STMT (t0)))
2761 : : {
2762 : 11217 : incr_vec[incr_vec_len].initializer = t0;
2763 : 11217 : incr_vec[incr_vec_len++].init_bb
2764 : 11217 : = gimple_bb (SSA_NAME_DEF_STMT (t0));
2765 : : }
2766 : : else
2767 : : {
2768 : 6 : incr_vec[incr_vec_len].initializer = NULL_TREE;
2769 : 6 : incr_vec[incr_vec_len++].init_bb = NULL;
2770 : : }
2771 : : }
2772 : : else
2773 : : {
2774 : 86403 : incr_vec[incr_vec_len].initializer = NULL_TREE;
2775 : 86403 : incr_vec[incr_vec_len++].init_bb = NULL;
2776 : : }
2777 : : }
2778 : 141366 : }
2779 : :
2780 : : /* Recursive helper function for record_phi_increments. */
2781 : :
2782 : : static void
2783 : 12 : record_phi_increments_1 (slsr_cand_t basis, gimple *phi)
2784 : : {
2785 : 12 : unsigned i;
2786 : 12 : slsr_cand_t phi_cand = *stmt_cand_map->get (phi);
2787 : :
2788 : 12 : if (phi_cand->visited)
2789 : : return;
2790 : 12 : phi_cand->visited = 1;
2791 : :
2792 : 36 : for (i = 0; i < gimple_phi_num_args (phi); i++)
2793 : : {
2794 : 24 : tree arg = gimple_phi_arg_def (phi, i);
2795 : 24 : gimple *arg_def = SSA_NAME_DEF_STMT (arg);
2796 : :
2797 : 24 : if (gimple_code (arg_def) == GIMPLE_PHI)
2798 : 0 : record_phi_increments_1 (basis, arg_def);
2799 : : else
2800 : : {
2801 : 24 : offset_int diff;
2802 : :
2803 : 24 : if (operand_equal_p (arg, phi_cand->base_expr, 0))
2804 : : {
2805 : 7 : diff = -basis->index;
2806 : 7 : record_increment (phi_cand, diff, PHI_ADJUST);
2807 : : }
2808 : : else
2809 : : {
2810 : 17 : slsr_cand_t arg_cand = base_cand_from_table (arg);
2811 : 17 : diff = arg_cand->index - basis->index;
2812 : 17 : record_increment (arg_cand, diff, PHI_ADJUST);
2813 : : }
2814 : : }
2815 : : }
2816 : : }
2817 : :
2818 : : /* Given phi statement PHI that hides a candidate from its BASIS, find
2819 : : the increments along each incoming arc (recursively handling additional
2820 : : phis that may be present) and record them. These increments are the
2821 : : difference in index between the index-adjusting statements and the
2822 : : index of the basis. */
2823 : :
2824 : : static void
2825 : 12 : record_phi_increments (slsr_cand_t basis, gimple *phi)
2826 : : {
2827 : 12 : record_phi_increments_1 (basis, phi);
2828 : 12 : clear_visited (as_a <gphi *> (phi));
2829 : 12 : }
2830 : :
2831 : : /* Determine how many times each unique increment occurs in the set
2832 : : of candidates rooted at C's parent, recording the data in the
2833 : : increment vector. For each unique increment I, if an initializer
2834 : : T_0 = stride * I is provided by a candidate that dominates all
2835 : : candidates with the same increment, also record T_0 for subsequent
2836 : : use. */
2837 : :
2838 : : static void
2839 : 54495 : record_increments (slsr_cand_t c)
2840 : : {
2841 : 141342 : if (!cand_already_replaced (c))
2842 : : {
2843 : 141342 : if (!phi_dependent_cand_p (c))
2844 : 141330 : record_increment (c, cand_increment (c), NOT_PHI_ADJUST);
2845 : : else
2846 : : {
2847 : : /* A candidate with a basis hidden by a phi will have one
2848 : : increment for its relationship to the index represented by
2849 : : the phi, and potentially additional increments along each
2850 : : incoming edge. For the root of the dependency tree (which
2851 : : has no basis), process just the initial index in case it has
2852 : : an initializer that can be used by subsequent candidates. */
2853 : 12 : record_increment (c, c->index, NOT_PHI_ADJUST);
2854 : :
2855 : 12 : if (c->basis)
2856 : 12 : record_phi_increments (lookup_cand (c->basis),
2857 : 12 : lookup_cand (c->def_phi)->cand_stmt);
2858 : : }
2859 : : }
2860 : :
2861 : 141342 : if (c->sibling)
2862 : 2482 : record_increments (lookup_cand (c->sibling));
2863 : :
2864 : 141342 : if (c->dependent)
2865 : 86847 : record_increments (lookup_cand (c->dependent));
2866 : 54495 : }
2867 : :
2868 : : /* Recursive helper function for phi_incr_cost. */
2869 : :
2870 : : static int
2871 : 15 : phi_incr_cost_1 (slsr_cand_t c, const offset_int &incr, gimple *phi,
2872 : : int *savings)
2873 : : {
2874 : 15 : unsigned i;
2875 : 15 : int cost = 0;
2876 : 15 : slsr_cand_t basis = lookup_cand (c->basis);
2877 : 15 : slsr_cand_t phi_cand = *stmt_cand_map->get (phi);
2878 : :
2879 : 15 : if (phi_cand->visited)
2880 : : return 0;
2881 : 15 : phi_cand->visited = 1;
2882 : :
2883 : 45 : for (i = 0; i < gimple_phi_num_args (phi); i++)
2884 : : {
2885 : 30 : tree arg = gimple_phi_arg_def (phi, i);
2886 : 30 : gimple *arg_def = SSA_NAME_DEF_STMT (arg);
2887 : :
2888 : 30 : if (gimple_code (arg_def) == GIMPLE_PHI)
2889 : : {
2890 : 0 : int feeding_savings = 0;
2891 : 0 : tree feeding_var = gimple_phi_result (arg_def);
2892 : 0 : cost += phi_incr_cost_1 (c, incr, arg_def, &feeding_savings);
2893 : 0 : if (uses_consumed_by_stmt (feeding_var, phi))
2894 : 0 : *savings += feeding_savings;
2895 : : }
2896 : : else
2897 : : {
2898 : 30 : offset_int diff;
2899 : 30 : slsr_cand_t arg_cand;
2900 : :
2901 : : /* When the PHI argument is just a pass-through to the base
2902 : : expression of the hidden basis, the difference is zero minus
2903 : : the index of the basis. There is no potential savings by
2904 : : eliminating a statement in this case. */
2905 : 30 : if (operand_equal_p (arg, phi_cand->base_expr, 0))
2906 : : {
2907 : 7 : arg_cand = (slsr_cand_t)NULL;
2908 : 7 : diff = -basis->index;
2909 : : }
2910 : : else
2911 : : {
2912 : 23 : arg_cand = base_cand_from_table (arg);
2913 : 23 : diff = arg_cand->index - basis->index;
2914 : : }
2915 : :
2916 : 30 : if (incr == diff)
2917 : : {
2918 : 14 : tree basis_lhs = gimple_assign_lhs (basis->cand_stmt);
2919 : 14 : cost += add_cost (true, TYPE_MODE (TREE_TYPE (basis_lhs)));
2920 : 14 : if (arg_cand)
2921 : : {
2922 : 14 : tree lhs = gimple_assign_lhs (arg_cand->cand_stmt);
2923 : 14 : if (uses_consumed_by_stmt (lhs, phi))
2924 : 14 : *savings += stmt_cost (arg_cand->cand_stmt, true);
2925 : : }
2926 : : }
2927 : : }
2928 : : }
2929 : :
2930 : : return cost;
2931 : : }
2932 : :
2933 : : /* Add up and return the costs of introducing add statements that
2934 : : require the increment INCR on behalf of candidate C and phi
2935 : : statement PHI. Accumulate into *SAVINGS the potential savings
2936 : : from removing existing statements that feed PHI and have no other
2937 : : uses. */
2938 : :
2939 : : static int
2940 : 15 : phi_incr_cost (slsr_cand_t c, const offset_int &incr, gimple *phi,
2941 : : int *savings)
2942 : : {
2943 : 15 : int retval = phi_incr_cost_1 (c, incr, phi, savings);
2944 : 15 : clear_visited (as_a <gphi *> (phi));
2945 : 15 : return retval;
2946 : : }
2947 : :
2948 : : /* Return the first candidate in the tree rooted at C that has not
2949 : : already been replaced, favoring siblings over dependents. */
2950 : :
2951 : : static slsr_cand_t
2952 : 52013 : unreplaced_cand_in_tree (slsr_cand_t c)
2953 : : {
2954 : 52013 : if (!cand_already_replaced (c))
2955 : : return c;
2956 : :
2957 : 0 : if (c->sibling)
2958 : : {
2959 : 0 : slsr_cand_t sib = unreplaced_cand_in_tree (lookup_cand (c->sibling));
2960 : 0 : if (sib)
2961 : : return sib;
2962 : : }
2963 : :
2964 : 0 : if (c->dependent)
2965 : : {
2966 : 0 : slsr_cand_t dep = unreplaced_cand_in_tree (lookup_cand (c->dependent));
2967 : 0 : if (dep)
2968 : : return dep;
2969 : : }
2970 : :
2971 : : return NULL;
2972 : : }
2973 : :
2974 : : /* Return TRUE if the candidates in the tree rooted at C should be
2975 : : optimized for speed, else FALSE. We estimate this based on the block
2976 : : containing the most dominant candidate in the tree that has not yet
2977 : : been replaced. */
2978 : :
2979 : : static bool
2980 : 52013 : optimize_cands_for_speed_p (slsr_cand_t c)
2981 : : {
2982 : 52013 : slsr_cand_t c2 = unreplaced_cand_in_tree (c);
2983 : 52013 : gcc_assert (c2);
2984 : 52013 : return optimize_bb_for_speed_p (gimple_bb (c2->cand_stmt));
2985 : : }
2986 : :
2987 : : /* Add COST_IN to the lowest cost of any dependent path starting at
2988 : : candidate C or any of its siblings, counting only candidates along
2989 : : such paths with increment INCR. Assume that replacing a candidate
2990 : : reduces cost by REPL_SAVINGS. Also account for savings from any
2991 : : statements that would go dead. If COUNT_PHIS is true, include
2992 : : costs of introducing feeding statements for conditional candidates. */
2993 : :
2994 : : static int
2995 : 4142 : lowest_cost_path (int cost_in, int repl_savings, slsr_cand_t c,
2996 : : const offset_int &incr, bool count_phis)
2997 : : {
2998 : 4142 : int local_cost, sib_cost, savings = 0;
2999 : 4142 : offset_int cand_incr = cand_abs_increment (c);
3000 : :
3001 : 4142 : if (cand_already_replaced (c))
3002 : : local_cost = cost_in;
3003 : 4142 : else if (incr == cand_incr)
3004 : 2972 : local_cost = cost_in - repl_savings - c->dead_savings;
3005 : : else
3006 : 1170 : local_cost = cost_in - c->dead_savings;
3007 : :
3008 : 4142 : if (count_phis
3009 : 239 : && phi_dependent_cand_p (c)
3010 : 4156 : && !cand_already_replaced (c))
3011 : : {
3012 : 14 : gimple *phi = lookup_cand (c->def_phi)->cand_stmt;
3013 : 14 : local_cost += phi_incr_cost (c, incr, phi, &savings);
3014 : :
3015 : 14 : if (uses_consumed_by_stmt (gimple_phi_result (phi), c->cand_stmt))
3016 : 8 : local_cost -= savings;
3017 : : }
3018 : :
3019 : 4142 : if (c->dependent)
3020 : 1573 : local_cost = lowest_cost_path (local_cost, repl_savings,
3021 : : lookup_cand (c->dependent), incr,
3022 : : count_phis);
3023 : :
3024 : 4142 : if (c->sibling)
3025 : : {
3026 : 113 : sib_cost = lowest_cost_path (cost_in, repl_savings,
3027 : : lookup_cand (c->sibling), incr,
3028 : : count_phis);
3029 : 113 : local_cost = MIN (local_cost, sib_cost);
3030 : : }
3031 : :
3032 : 4142 : return local_cost;
3033 : : }
3034 : :
3035 : : /* Compute the total savings that would accrue from all replacements
3036 : : in the candidate tree rooted at C, counting only candidates with
3037 : : increment INCR. Assume that replacing a candidate reduces cost
3038 : : by REPL_SAVINGS. Also account for savings from statements that
3039 : : would go dead. */
3040 : :
3041 : : static int
3042 : 179 : total_savings (int repl_savings, slsr_cand_t c, const offset_int &incr,
3043 : : bool count_phis)
3044 : : {
3045 : 179 : int savings = 0;
3046 : 179 : offset_int cand_incr = cand_abs_increment (c);
3047 : :
3048 : 179 : if (incr == cand_incr && !cand_already_replaced (c))
3049 : 134 : savings += repl_savings + c->dead_savings;
3050 : :
3051 : 179 : if (count_phis
3052 : 102 : && phi_dependent_cand_p (c)
3053 : 180 : && !cand_already_replaced (c))
3054 : : {
3055 : 1 : int phi_savings = 0;
3056 : 1 : gimple *phi = lookup_cand (c->def_phi)->cand_stmt;
3057 : 1 : savings -= phi_incr_cost (c, incr, phi, &phi_savings);
3058 : :
3059 : 1 : if (uses_consumed_by_stmt (gimple_phi_result (phi), c->cand_stmt))
3060 : 1 : savings += phi_savings;
3061 : : }
3062 : :
3063 : 179 : if (c->dependent)
3064 : 106 : savings += total_savings (repl_savings, lookup_cand (c->dependent), incr,
3065 : : count_phis);
3066 : :
3067 : 179 : if (c->sibling)
3068 : 0 : savings += total_savings (repl_savings, lookup_cand (c->sibling), incr,
3069 : : count_phis);
3070 : :
3071 : 179 : return savings;
3072 : : }
3073 : :
3074 : : /* Use target-specific costs to determine and record which increments
3075 : : in the current candidate tree are profitable to replace, assuming
3076 : : MODE and SPEED. FIRST_DEP is the first dependent of the root of
3077 : : the candidate tree.
3078 : :
3079 : : One slight limitation here is that we don't account for the possible
3080 : : introduction of casts in some cases. See replace_one_candidate for
3081 : : the cases where these are introduced. This should probably be cleaned
3082 : : up sometime. */
3083 : :
3084 : : static void
3085 : 52013 : analyze_increments (slsr_cand_t first_dep, machine_mode mode, bool speed)
3086 : : {
3087 : 52013 : unsigned i;
3088 : :
3089 : 149639 : for (i = 0; i < incr_vec_len; i++)
3090 : : {
3091 : 97626 : HOST_WIDE_INT incr = incr_vec[i].incr.to_shwi ();
3092 : :
3093 : : /* If somehow this increment is bigger than a HWI, we won't
3094 : : be optimizing candidates that use it. And if the increment
3095 : : has a count of zero, nothing will be done with it. */
3096 : 97626 : if (!wi::fits_shwi_p (incr_vec[i].incr) || !incr_vec[i].count)
3097 : 45062 : incr_vec[i].cost = COST_INFINITE;
3098 : :
3099 : : /* Increments of 0, 1, and -1 are always profitable to replace,
3100 : : because they always replace a multiply or add with an add or
3101 : : copy, and may cause one or more existing instructions to go
3102 : : dead. Exception: -1 can't be assumed to be profitable for
3103 : : pointer addition. */
3104 : 52564 : else if (incr == 0
3105 : 52564 : || incr == 1
3106 : 2559 : || (incr == -1
3107 : 8 : && !POINTER_TYPE_P (first_dep->cand_type)))
3108 : 50005 : incr_vec[i].cost = COST_NEUTRAL;
3109 : :
3110 : : /* If we need to add an initializer, give up if a cast from the
3111 : : candidate's type to its stride's type can lose precision.
3112 : : Note that this already takes into account that the stride may
3113 : : have been cast to a wider type, in which case this test won't
3114 : : fire. Example:
3115 : :
3116 : : short int _1;
3117 : : _2 = (int) _1;
3118 : : _3 = _2 * 10;
3119 : : _4 = x + _3; ADD: x + (10 * (int)_1) : int
3120 : : _5 = _2 * 15;
3121 : : _6 = x + _5; ADD: x + (15 * (int)_1) : int
3122 : :
3123 : : Although the stride was a short int initially, the stride
3124 : : used in the analysis has been widened to an int, and such
3125 : : widening will be done in the initializer as well. */
3126 : 2559 : else if (!incr_vec[i].initializer
3127 : 2046 : && TREE_CODE (first_dep->stride) != INTEGER_CST
3128 : 4605 : && !legal_cast_p_1 (first_dep->stride_type,
3129 : 2046 : TREE_TYPE (gimple_assign_lhs
3130 : : (first_dep->cand_stmt))))
3131 : 30 : incr_vec[i].cost = COST_INFINITE;
3132 : :
3133 : : /* If we need to add an initializer, make sure we don't introduce
3134 : : a multiply by a pointer type, which can happen in certain cast
3135 : : scenarios. */
3136 : 2529 : else if (!incr_vec[i].initializer
3137 : 2016 : && TREE_CODE (first_dep->stride) != INTEGER_CST
3138 : 2016 : && POINTER_TYPE_P (first_dep->stride_type))
3139 : 0 : incr_vec[i].cost = COST_INFINITE;
3140 : :
3141 : : /* For any other increment, if this is a multiply candidate, we
3142 : : must introduce a temporary T and initialize it with
3143 : : T_0 = stride * increment. When optimizing for speed, walk the
3144 : : candidate tree to calculate the best cost reduction along any
3145 : : path; if it offsets the fixed cost of inserting the initializer,
3146 : : replacing the increment is profitable. When optimizing for
3147 : : size, instead calculate the total cost reduction from replacing
3148 : : all candidates with this increment. */
3149 : 2529 : else if (first_dep->kind == CAND_MULT)
3150 : : {
3151 : 109 : int cost = mult_by_coeff_cost (incr, mode, speed);
3152 : 109 : int repl_savings;
3153 : :
3154 : 109 : if (tree_fits_shwi_p (first_dep->stride))
3155 : : {
3156 : 0 : HOST_WIDE_INT hwi_stride = tree_to_shwi (first_dep->stride);
3157 : 0 : repl_savings = mult_by_coeff_cost (hwi_stride, mode, speed);
3158 : : }
3159 : : else
3160 : 109 : repl_savings = mul_cost (speed, mode);
3161 : 109 : repl_savings -= add_cost (speed, mode);
3162 : :
3163 : 109 : if (speed)
3164 : 103 : cost = lowest_cost_path (cost, repl_savings, first_dep,
3165 : 103 : incr_vec[i].incr, COUNT_PHIS);
3166 : : else
3167 : 6 : cost -= total_savings (repl_savings, first_dep, incr_vec[i].incr,
3168 : : COUNT_PHIS);
3169 : :
3170 : 109 : incr_vec[i].cost = cost;
3171 : : }
3172 : :
3173 : : /* If this is an add candidate, the initializer may already
3174 : : exist, so only calculate the cost of the initializer if it
3175 : : doesn't. We are replacing one add with another here, so the
3176 : : known replacement savings is zero. We will account for removal
3177 : : of dead instructions in lowest_cost_path or total_savings. */
3178 : : else
3179 : : {
3180 : 2420 : int cost = 0;
3181 : 2420 : if (!incr_vec[i].initializer)
3182 : 1907 : cost = mult_by_coeff_cost (incr, mode, speed);
3183 : :
3184 : 2420 : if (speed)
3185 : 2353 : cost = lowest_cost_path (cost, 0, first_dep, incr_vec[i].incr,
3186 : : DONT_COUNT_PHIS);
3187 : : else
3188 : 67 : cost -= total_savings (0, first_dep, incr_vec[i].incr,
3189 : : DONT_COUNT_PHIS);
3190 : :
3191 : 2420 : incr_vec[i].cost = cost;
3192 : : }
3193 : : }
3194 : 52013 : }
3195 : :
3196 : : /* Return the nearest common dominator of BB1 and BB2. If the blocks
3197 : : are identical, return the earlier of C1 and C2 in *WHERE. Otherwise,
3198 : : if the NCD matches BB1, return C1 in *WHERE; if the NCD matches BB2,
3199 : : return C2 in *WHERE; and if the NCD matches neither, return NULL in
3200 : : *WHERE. Note: It is possible for one of C1 and C2 to be NULL. */
3201 : :
3202 : : static basic_block
3203 : 555 : ncd_for_two_cands (basic_block bb1, basic_block bb2,
3204 : : slsr_cand_t c1, slsr_cand_t c2, slsr_cand_t *where)
3205 : : {
3206 : 555 : basic_block ncd;
3207 : :
3208 : 555 : if (!bb1)
3209 : : {
3210 : 369 : *where = c2;
3211 : 369 : return bb2;
3212 : : }
3213 : :
3214 : 186 : if (!bb2)
3215 : : {
3216 : 0 : *where = c1;
3217 : 0 : return bb1;
3218 : : }
3219 : :
3220 : 186 : ncd = nearest_common_dominator (CDI_DOMINATORS, bb1, bb2);
3221 : :
3222 : : /* If both candidates are in the same block, the earlier
3223 : : candidate wins. */
3224 : 186 : if (bb1 == ncd && bb2 == ncd)
3225 : : {
3226 : 164 : if (!c1 || (c2 && c2->cand_num < c1->cand_num))
3227 : 164 : *where = c2;
3228 : : else
3229 : 0 : *where = c1;
3230 : : }
3231 : :
3232 : : /* Otherwise, if one of them produced a candidate in the
3233 : : dominator, that one wins. */
3234 : 22 : else if (bb1 == ncd)
3235 : 4 : *where = c1;
3236 : :
3237 : 18 : else if (bb2 == ncd)
3238 : 5 : *where = c2;
3239 : :
3240 : : /* If neither matches the dominator, neither wins. */
3241 : : else
3242 : 13 : *where = NULL;
3243 : :
3244 : : return ncd;
3245 : : }
3246 : :
3247 : : /* Consider all candidates that feed PHI. Find the nearest common
3248 : : dominator of those candidates requiring the given increment INCR.
3249 : : Further find and return the nearest common dominator of this result
3250 : : with block NCD. If the returned block contains one or more of the
3251 : : candidates, return the earliest candidate in the block in *WHERE. */
3252 : :
3253 : : static basic_block
3254 : 8 : ncd_with_phi (slsr_cand_t c, const offset_int &incr, gphi *phi,
3255 : : basic_block ncd, slsr_cand_t *where)
3256 : : {
3257 : 8 : unsigned i;
3258 : 8 : slsr_cand_t basis = lookup_cand (c->basis);
3259 : 8 : slsr_cand_t phi_cand = *stmt_cand_map->get (phi);
3260 : :
3261 : 24 : for (i = 0; i < gimple_phi_num_args (phi); i++)
3262 : : {
3263 : 16 : tree arg = gimple_phi_arg_def (phi, i);
3264 : 16 : gimple *arg_def = SSA_NAME_DEF_STMT (arg);
3265 : :
3266 : 16 : if (gimple_code (arg_def) == GIMPLE_PHI)
3267 : 0 : ncd = ncd_with_phi (c, incr, as_a <gphi *> (arg_def), ncd, where);
3268 : : else
3269 : : {
3270 : 16 : offset_int diff;
3271 : :
3272 : 16 : if (operand_equal_p (arg, phi_cand->base_expr, 0))
3273 : 6 : diff = -basis->index;
3274 : : else
3275 : : {
3276 : 10 : slsr_cand_t arg_cand = base_cand_from_table (arg);
3277 : 10 : diff = arg_cand->index - basis->index;
3278 : : }
3279 : :
3280 : 16 : basic_block pred = gimple_phi_arg_edge (phi, i)->src;
3281 : :
3282 : 25 : if ((incr == diff) || (!address_arithmetic_p && incr == -diff))
3283 : 8 : ncd = ncd_for_two_cands (ncd, pred, *where, NULL, where);
3284 : : }
3285 : : }
3286 : :
3287 : 8 : return ncd;
3288 : : }
3289 : :
3290 : : /* Consider the candidate C together with any candidates that feed
3291 : : C's phi dependence (if any). Find and return the nearest common
3292 : : dominator of those candidates requiring the given increment INCR.
3293 : : If the returned block contains one or more of the candidates,
3294 : : return the earliest candidate in the block in *WHERE. */
3295 : :
3296 : : static basic_block
3297 : 1253 : ncd_of_cand_and_phis (slsr_cand_t c, const offset_int &incr, slsr_cand_t *where)
3298 : : {
3299 : 1253 : basic_block ncd = NULL;
3300 : :
3301 : 1253 : if (cand_abs_increment (c) == incr)
3302 : : {
3303 : 542 : ncd = gimple_bb (c->cand_stmt);
3304 : 542 : *where = c;
3305 : : }
3306 : :
3307 : 1253 : if (phi_dependent_cand_p (c))
3308 : 8 : ncd = ncd_with_phi (c, incr,
3309 : 8 : as_a <gphi *> (lookup_cand (c->def_phi)->cand_stmt),
3310 : : ncd, where);
3311 : :
3312 : 1253 : return ncd;
3313 : : }
3314 : :
3315 : : /* Consider all candidates in the tree rooted at C for which INCR
3316 : : represents the required increment of C relative to its basis.
3317 : : Find and return the basic block that most nearly dominates all
3318 : : such candidates. If the returned block contains one or more of
3319 : : the candidates, return the earliest candidate in the block in
3320 : : *WHERE. */
3321 : :
3322 : : static basic_block
3323 : 1253 : nearest_common_dominator_for_cands (slsr_cand_t c, const offset_int &incr,
3324 : : slsr_cand_t *where)
3325 : : {
3326 : 1253 : basic_block sib_ncd = NULL, dep_ncd = NULL, this_ncd = NULL, ncd;
3327 : 1253 : slsr_cand_t sib_where = NULL, dep_where = NULL, this_where = NULL, new_where;
3328 : :
3329 : : /* First find the NCD of all siblings and dependents. */
3330 : 1253 : if (c->sibling)
3331 : 63 : sib_ncd = nearest_common_dominator_for_cands (lookup_cand (c->sibling),
3332 : : incr, &sib_where);
3333 : 1253 : if (c->dependent)
3334 : 826 : dep_ncd = nearest_common_dominator_for_cands (lookup_cand (c->dependent),
3335 : : incr, &dep_where);
3336 : 1253 : if (!sib_ncd && !dep_ncd)
3337 : : {
3338 : 636 : new_where = NULL;
3339 : 636 : ncd = NULL;
3340 : : }
3341 : 617 : else if (sib_ncd && !dep_ncd)
3342 : : {
3343 : 47 : new_where = sib_where;
3344 : 47 : ncd = sib_ncd;
3345 : : }
3346 : 570 : else if (dep_ncd && !sib_ncd)
3347 : : {
3348 : 570 : new_where = dep_where;
3349 : 570 : ncd = dep_ncd;
3350 : : }
3351 : : else
3352 : 0 : ncd = ncd_for_two_cands (sib_ncd, dep_ncd, sib_where,
3353 : : dep_where, &new_where);
3354 : :
3355 : : /* If the candidate's increment doesn't match the one we're interested
3356 : : in (and nor do any increments for feeding defs of a phi-dependence),
3357 : : then the result depends only on siblings and dependents. */
3358 : 1253 : this_ncd = ncd_of_cand_and_phis (c, incr, &this_where);
3359 : :
3360 : 1253 : if (!this_ncd || cand_already_replaced (c))
3361 : : {
3362 : 706 : *where = new_where;
3363 : 706 : return ncd;
3364 : : }
3365 : :
3366 : : /* Otherwise, compare this candidate with the result from all siblings
3367 : : and dependents. */
3368 : 547 : ncd = ncd_for_two_cands (ncd, this_ncd, new_where, this_where, where);
3369 : :
3370 : 547 : return ncd;
3371 : : }
3372 : :
3373 : : /* Return TRUE if the increment indexed by INDEX is profitable to replace. */
3374 : :
3375 : : static inline bool
3376 : 186976 : profitable_increment_p (unsigned index)
3377 : : {
3378 : 186976 : return (incr_vec[index].cost <= COST_NEUTRAL);
3379 : : }
3380 : :
3381 : : /* For each profitable increment in the increment vector not equal to
3382 : : 0 or 1 (or -1, for non-pointer arithmetic), find the nearest common
3383 : : dominator of all statements in the candidate chain rooted at C
3384 : : that require that increment, and insert an initializer
3385 : : T_0 = stride * increment at that location. Record T_0 with the
3386 : : increment record. */
3387 : :
3388 : : static void
3389 : 52013 : insert_initializers (slsr_cand_t c)
3390 : : {
3391 : 52013 : unsigned i;
3392 : :
3393 : 149639 : for (i = 0; i < incr_vec_len; i++)
3394 : : {
3395 : 97626 : basic_block bb;
3396 : 97626 : slsr_cand_t where = NULL;
3397 : 97626 : gassign *init_stmt;
3398 : 97626 : gassign *cast_stmt = NULL;
3399 : 97626 : tree new_name, incr_tree, init_stride;
3400 : 97626 : offset_int incr = incr_vec[i].incr;
3401 : :
3402 : 194375 : if (!profitable_increment_p (i)
3403 : 50882 : || incr == 1
3404 : 46920 : || (incr == -1
3405 : 4 : && (!POINTER_TYPE_P (lookup_cand (c->basis)->cand_type)))
3406 : 144546 : || incr == 0)
3407 : 97262 : continue;
3408 : :
3409 : : /* We may have already identified an existing initializer that
3410 : : will suffice. */
3411 : 877 : if (incr_vec[i].initializer)
3412 : : {
3413 : 513 : if (dump_file && (dump_flags & TDF_DETAILS))
3414 : : {
3415 : 0 : fputs ("Using existing initializer: ", dump_file);
3416 : 0 : print_gimple_stmt (dump_file,
3417 : 0 : SSA_NAME_DEF_STMT (incr_vec[i].initializer),
3418 : : 0, TDF_NONE);
3419 : : }
3420 : 513 : continue;
3421 : : }
3422 : :
3423 : : /* Find the block that most closely dominates all candidates
3424 : : with this increment. If there is at least one candidate in
3425 : : that block, the earliest one will be returned in WHERE. */
3426 : 364 : bb = nearest_common_dominator_for_cands (c, incr, &where);
3427 : :
3428 : : /* If the NCD is not dominated by the block containing the
3429 : : definition of the stride, we can't legally insert a
3430 : : single initializer. Mark the increment as unprofitable
3431 : : so we don't make any replacements. FIXME: Multiple
3432 : : initializers could be placed with more analysis. */
3433 : 364 : gimple *stride_def = SSA_NAME_DEF_STMT (c->stride);
3434 : 364 : basic_block stride_bb = gimple_bb (stride_def);
3435 : :
3436 : 364 : if (stride_bb && !dominated_by_p (CDI_DOMINATORS, bb, stride_bb))
3437 : : {
3438 : 0 : if (dump_file && (dump_flags & TDF_DETAILS))
3439 : 0 : fprintf (dump_file,
3440 : : "Initializer #%d cannot be legally placed\n", i);
3441 : 0 : incr_vec[i].cost = COST_INFINITE;
3442 : 0 : continue;
3443 : : }
3444 : :
3445 : : /* If the nominal stride has a different type than the recorded
3446 : : stride type, build a cast from the nominal stride to that type. */
3447 : 364 : if (!types_compatible_p (TREE_TYPE (c->stride), c->stride_type))
3448 : : {
3449 : 228 : init_stride = make_temp_ssa_name (c->stride_type, NULL, "slsr");
3450 : 228 : cast_stmt = gimple_build_assign (init_stride, NOP_EXPR, c->stride);
3451 : : }
3452 : : else
3453 : 136 : init_stride = c->stride;
3454 : :
3455 : : /* Create a new SSA name to hold the initializer's value. */
3456 : 364 : new_name = make_temp_ssa_name (c->stride_type, NULL, "slsr");
3457 : 364 : incr_vec[i].initializer = new_name;
3458 : :
3459 : : /* Create the initializer and insert it in the latest possible
3460 : : dominating position. */
3461 : 364 : incr_tree = wide_int_to_tree (c->stride_type, incr);
3462 : 364 : init_stmt = gimple_build_assign (new_name, MULT_EXPR,
3463 : : init_stride, incr_tree);
3464 : 364 : if (where)
3465 : : {
3466 : 348 : gimple_stmt_iterator gsi = gsi_for_stmt (where->cand_stmt);
3467 : 348 : location_t loc = gimple_location (where->cand_stmt);
3468 : :
3469 : 348 : if (cast_stmt)
3470 : : {
3471 : 228 : gsi_insert_before (&gsi, cast_stmt, GSI_SAME_STMT);
3472 : 228 : gimple_set_location (cast_stmt, loc);
3473 : : }
3474 : :
3475 : 348 : gsi_insert_before (&gsi, init_stmt, GSI_SAME_STMT);
3476 : 348 : gimple_set_location (init_stmt, loc);
3477 : : }
3478 : : else
3479 : : {
3480 : 16 : gimple_stmt_iterator gsi = gsi_last_bb (bb);
3481 : 16 : gimple *basis_stmt = lookup_cand (c->basis)->cand_stmt;
3482 : 16 : location_t loc = gimple_location (basis_stmt);
3483 : :
3484 : 16 : if (!gsi_end_p (gsi) && stmt_ends_bb_p (gsi_stmt (gsi)))
3485 : : {
3486 : 16 : if (cast_stmt)
3487 : : {
3488 : 0 : gsi_insert_before (&gsi, cast_stmt, GSI_SAME_STMT);
3489 : 0 : gimple_set_location (cast_stmt, loc);
3490 : : }
3491 : 16 : gsi_insert_before (&gsi, init_stmt, GSI_SAME_STMT);
3492 : : }
3493 : : else
3494 : : {
3495 : 0 : if (cast_stmt)
3496 : : {
3497 : 0 : gsi_insert_after (&gsi, cast_stmt, GSI_NEW_STMT);
3498 : 0 : gimple_set_location (cast_stmt, loc);
3499 : : }
3500 : 0 : gsi_insert_after (&gsi, init_stmt, GSI_NEW_STMT);
3501 : : }
3502 : :
3503 : 16 : gimple_set_location (init_stmt, gimple_location (basis_stmt));
3504 : : }
3505 : :
3506 : 364 : if (dump_file && (dump_flags & TDF_DETAILS))
3507 : : {
3508 : 0 : if (cast_stmt)
3509 : : {
3510 : 0 : fputs ("Inserting stride cast: ", dump_file);
3511 : 0 : print_gimple_stmt (dump_file, cast_stmt, 0);
3512 : : }
3513 : 0 : fputs ("Inserting initializer: ", dump_file);
3514 : 0 : print_gimple_stmt (dump_file, init_stmt, 0);
3515 : : }
3516 : : }
3517 : 52013 : }
3518 : :
3519 : : /* Recursive helper function for all_phi_incrs_profitable. */
3520 : :
3521 : : static bool
3522 : 12 : all_phi_incrs_profitable_1 (slsr_cand_t c, gphi *phi, int *spread)
3523 : : {
3524 : 12 : unsigned i;
3525 : 12 : slsr_cand_t basis = lookup_cand (c->basis);
3526 : 12 : slsr_cand_t phi_cand = *stmt_cand_map->get (phi);
3527 : :
3528 : 12 : if (phi_cand->visited)
3529 : : return true;
3530 : :
3531 : 12 : phi_cand->visited = 1;
3532 : 12 : (*spread)++;
3533 : :
3534 : : /* If the basis doesn't dominate the PHI (including when the PHI is
3535 : : in the same block as the basis), we won't be able to create a PHI
3536 : : using the basis here. */
3537 : 12 : basic_block basis_bb = gimple_bb (basis->cand_stmt);
3538 : 12 : basic_block phi_bb = gimple_bb (phi);
3539 : :
3540 : 12 : if (phi_bb == basis_bb
3541 : 12 : || !dominated_by_p (CDI_DOMINATORS, phi_bb, basis_bb))
3542 : 0 : return false;
3543 : :
3544 : 29 : for (i = 0; i < gimple_phi_num_args (phi); i++)
3545 : : {
3546 : : /* If the PHI arg resides in a block not dominated by the basis,
3547 : : we won't be able to create a PHI using the basis here. */
3548 : 21 : basic_block pred_bb = gimple_phi_arg_edge (phi, i)->src;
3549 : :
3550 : 21 : if (!dominated_by_p (CDI_DOMINATORS, pred_bb, basis_bb))
3551 : : return false;
3552 : :
3553 : 21 : tree arg = gimple_phi_arg_def (phi, i);
3554 : 21 : gimple *arg_def = SSA_NAME_DEF_STMT (arg);
3555 : :
3556 : 21 : if (gimple_code (arg_def) == GIMPLE_PHI)
3557 : : {
3558 : 0 : if (!all_phi_incrs_profitable_1 (c, as_a <gphi *> (arg_def), spread)
3559 : 0 : || *spread > MAX_SPREAD)
3560 : : return false;
3561 : : }
3562 : : else
3563 : : {
3564 : 21 : int j;
3565 : 21 : offset_int increment;
3566 : :
3567 : 21 : if (operand_equal_p (arg, phi_cand->base_expr, 0))
3568 : 7 : increment = -basis->index;
3569 : : else
3570 : : {
3571 : 14 : slsr_cand_t arg_cand = base_cand_from_table (arg);
3572 : 14 : increment = arg_cand->index - basis->index;
3573 : : }
3574 : :
3575 : 21 : if (!address_arithmetic_p && wi::neg_p (increment))
3576 : 1 : increment = -increment;
3577 : :
3578 : 21 : j = incr_vec_index (increment);
3579 : :
3580 : 21 : if (dump_file && (dump_flags & TDF_DETAILS))
3581 : : {
3582 : 0 : fprintf (dump_file, " Conditional candidate %d, phi: ",
3583 : : c->cand_num);
3584 : 0 : print_gimple_stmt (dump_file, phi, 0);
3585 : 0 : fputs (" increment: ", dump_file);
3586 : 0 : print_decs (increment, dump_file);
3587 : 0 : if (j < 0)
3588 : 0 : fprintf (dump_file,
3589 : : "\n Not replaced; incr_vec overflow.\n");
3590 : : else {
3591 : 0 : fprintf (dump_file, "\n cost: %d\n", incr_vec[j].cost);
3592 : 0 : if (profitable_increment_p (j))
3593 : 0 : fputs (" Replacing...\n", dump_file);
3594 : : else
3595 : 0 : fputs (" Not replaced.\n", dump_file);
3596 : : }
3597 : : }
3598 : :
3599 : 21 : if (j < 0 || !profitable_increment_p (j))
3600 : 4 : return false;
3601 : : }
3602 : : }
3603 : :
3604 : : return true;
3605 : : }
3606 : :
3607 : : /* Return TRUE iff all required increments for candidates feeding PHI
3608 : : are profitable (and legal!) to replace on behalf of candidate C. */
3609 : :
3610 : : static bool
3611 : 12 : all_phi_incrs_profitable (slsr_cand_t c, gphi *phi)
3612 : : {
3613 : 12 : int spread = 0;
3614 : 12 : bool retval = all_phi_incrs_profitable_1 (c, phi, &spread);
3615 : 12 : clear_visited (phi);
3616 : 12 : return retval;
3617 : : }
3618 : :
3619 : : /* Create a NOP_EXPR that copies FROM_EXPR into a new SSA name of
3620 : : type TO_TYPE, and insert it in front of the statement represented
3621 : : by candidate C. Use *NEW_VAR to create the new SSA name. Return
3622 : : the new SSA name. */
3623 : :
3624 : : static tree
3625 : 1106 : introduce_cast_before_cand (slsr_cand_t c, tree to_type, tree from_expr)
3626 : : {
3627 : 1106 : tree cast_lhs;
3628 : 1106 : gassign *cast_stmt;
3629 : 1106 : gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt);
3630 : :
3631 : 1106 : cast_lhs = make_temp_ssa_name (to_type, NULL, "slsr");
3632 : 1106 : cast_stmt = gimple_build_assign (cast_lhs, NOP_EXPR, from_expr);
3633 : 1106 : gimple_set_location (cast_stmt, gimple_location (c->cand_stmt));
3634 : 1106 : gsi_insert_before (&gsi, cast_stmt, GSI_SAME_STMT);
3635 : :
3636 : 1106 : if (dump_file && (dump_flags & TDF_DETAILS))
3637 : : {
3638 : 0 : fputs (" Inserting: ", dump_file);
3639 : 0 : print_gimple_stmt (dump_file, cast_stmt, 0);
3640 : : }
3641 : :
3642 : 1106 : return cast_lhs;
3643 : : }
3644 : :
3645 : : /* Replace the RHS of the statement represented by candidate C with
3646 : : NEW_CODE, NEW_RHS1, and NEW_RHS2, provided that to do so doesn't
3647 : : leave C unchanged or just interchange its operands. The original
3648 : : operation and operands are in OLD_CODE, OLD_RHS1, and OLD_RHS2.
3649 : : If the replacement was made and we are doing a details dump,
3650 : : return the revised statement, else NULL. */
3651 : :
3652 : : static gimple *
3653 : 10562 : replace_rhs_if_not_dup (enum tree_code new_code, tree new_rhs1, tree new_rhs2,
3654 : : enum tree_code old_code, tree old_rhs1, tree old_rhs2,
3655 : : slsr_cand_t c)
3656 : : {
3657 : 10562 : if (new_code != old_code
3658 : 10562 : || ((!operand_equal_p (new_rhs1, old_rhs1, 0)
3659 : 0 : || !operand_equal_p (new_rhs2, old_rhs2, 0))
3660 : 3104 : && (!operand_equal_p (new_rhs1, old_rhs2, 0)
3661 : 0 : || !operand_equal_p (new_rhs2, old_rhs1, 0))))
3662 : : {
3663 : 10562 : gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt);
3664 : 10562 : slsr_cand_t cc = lookup_cand (c->first_interp);
3665 : 10562 : gimple_assign_set_rhs_with_ops (&gsi, new_code, new_rhs1, new_rhs2);
3666 : 10562 : update_stmt (gsi_stmt (gsi));
3667 : 40886 : while (cc)
3668 : : {
3669 : 19762 : cc->cand_stmt = gsi_stmt (gsi);
3670 : 19762 : cc = lookup_cand (cc->next_interp);
3671 : : }
3672 : :
3673 : 10562 : if (dump_file && (dump_flags & TDF_DETAILS))
3674 : 0 : return gsi_stmt (gsi);
3675 : : }
3676 : :
3677 : 0 : else if (dump_file && (dump_flags & TDF_DETAILS))
3678 : 0 : fputs (" (duplicate, not actually replacing)\n", dump_file);
3679 : :
3680 : : return NULL;
3681 : : }
3682 : :
3683 : : /* Strength-reduce the statement represented by candidate C by replacing
3684 : : it with an equivalent addition or subtraction. I is the index into
3685 : : the increment vector identifying C's increment. NEW_VAR is used to
3686 : : create a new SSA name if a cast needs to be introduced. BASIS_NAME
3687 : : is the rhs1 to use in creating the add/subtract. */
3688 : :
3689 : : static void
3690 : 22552 : replace_one_candidate (slsr_cand_t c, unsigned i, tree basis_name,
3691 : : auto_bitmap &sdce_worklist)
3692 : : {
3693 : 22552 : gimple *stmt_to_print = NULL;
3694 : 22552 : tree orig_rhs1, orig_rhs2;
3695 : 22552 : tree rhs2;
3696 : 22552 : enum tree_code orig_code, repl_code;
3697 : 22552 : offset_int cand_incr;
3698 : :
3699 : 22552 : orig_code = gimple_assign_rhs_code (c->cand_stmt);
3700 : 22552 : orig_rhs1 = gimple_assign_rhs1 (c->cand_stmt);
3701 : 22552 : orig_rhs2 = gimple_assign_rhs2 (c->cand_stmt);
3702 : 22552 : cand_incr = cand_increment (c);
3703 : :
3704 : : /* If orig_rhs2 is NULL, we have already replaced this in situ with
3705 : : a copy statement under another interpretation. */
3706 : 22552 : if (!orig_rhs2)
3707 : 0 : return;
3708 : :
3709 : : /* Mark the 2 original rhs for maybe DCEing. */
3710 : 22552 : if (TREE_CODE (orig_rhs1) == SSA_NAME)
3711 : 22552 : bitmap_set_bit (sdce_worklist, SSA_NAME_VERSION (orig_rhs1));
3712 : 22552 : if (TREE_CODE (orig_rhs2) == SSA_NAME)
3713 : 22552 : bitmap_set_bit (sdce_worklist, SSA_NAME_VERSION (orig_rhs2));
3714 : :
3715 : 22552 : if (dump_file && (dump_flags & TDF_DETAILS))
3716 : : {
3717 : 0 : fputs ("Replacing: ", dump_file);
3718 : 0 : print_gimple_stmt (dump_file, c->cand_stmt, 0);
3719 : 0 : stmt_to_print = c->cand_stmt;
3720 : : }
3721 : :
3722 : 22552 : if (address_arithmetic_p)
3723 : : repl_code = POINTER_PLUS_EXPR;
3724 : : else
3725 : 18751 : repl_code = PLUS_EXPR;
3726 : :
3727 : : /* If the increment has an initializer T_0, replace the candidate
3728 : : statement with an add of the basis name and the initializer. */
3729 : 22552 : if (incr_vec[i].initializer)
3730 : : {
3731 : 1359 : tree init_type = TREE_TYPE (incr_vec[i].initializer);
3732 : 1359 : tree orig_type = TREE_TYPE (orig_rhs2);
3733 : :
3734 : 1359 : if (types_compatible_p (orig_type, init_type))
3735 : 1359 : rhs2 = incr_vec[i].initializer;
3736 : : else
3737 : 0 : rhs2 = introduce_cast_before_cand (c, orig_type,
3738 : 0 : incr_vec[i].initializer);
3739 : :
3740 : 1359 : if (incr_vec[i].incr != cand_incr)
3741 : : {
3742 : 154 : gcc_assert (repl_code == PLUS_EXPR);
3743 : : repl_code = MINUS_EXPR;
3744 : : }
3745 : :
3746 : 1359 : stmt_to_print = replace_rhs_if_not_dup (repl_code, basis_name, rhs2,
3747 : : orig_code, orig_rhs1, orig_rhs2,
3748 : : c);
3749 : : }
3750 : :
3751 : : /* Otherwise, the increment is one of -1, 0, and 1. Replace
3752 : : with a subtract of the stride from the basis name, a copy
3753 : : from the basis name, or an add of the stride to the basis
3754 : : name, respectively. It may be necessary to introduce a
3755 : : cast (or reuse an existing cast). */
3756 : 21193 : else if (cand_incr == 1)
3757 : : {
3758 : 9203 : tree stride_type = TREE_TYPE (c->stride);
3759 : 9203 : tree orig_type = TREE_TYPE (orig_rhs2);
3760 : :
3761 : 9203 : if (types_compatible_p (orig_type, stride_type))
3762 : 8150 : rhs2 = c->stride;
3763 : : else
3764 : 1053 : rhs2 = introduce_cast_before_cand (c, orig_type, c->stride);
3765 : :
3766 : 9203 : stmt_to_print = replace_rhs_if_not_dup (repl_code, basis_name, rhs2,
3767 : : orig_code, orig_rhs1, orig_rhs2,
3768 : : c);
3769 : : }
3770 : :
3771 : 11990 : else if (cand_incr == -1)
3772 : : {
3773 : 299 : tree stride_type = TREE_TYPE (c->stride);
3774 : 299 : tree orig_type = TREE_TYPE (orig_rhs2);
3775 : 299 : gcc_assert (repl_code != POINTER_PLUS_EXPR);
3776 : :
3777 : 299 : if (types_compatible_p (orig_type, stride_type))
3778 : 246 : rhs2 = c->stride;
3779 : : else
3780 : 53 : rhs2 = introduce_cast_before_cand (c, orig_type, c->stride);
3781 : :
3782 : 299 : if (orig_code != MINUS_EXPR
3783 : 42 : || !operand_equal_p (basis_name, orig_rhs1, 0)
3784 : 299 : || !operand_equal_p (rhs2, orig_rhs2, 0))
3785 : : {
3786 : 299 : gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt);
3787 : 299 : slsr_cand_t cc = lookup_cand (c->first_interp);
3788 : 299 : gimple_assign_set_rhs_with_ops (&gsi, MINUS_EXPR, basis_name, rhs2);
3789 : 299 : update_stmt (gsi_stmt (gsi));
3790 : 1154 : while (cc)
3791 : : {
3792 : 556 : cc->cand_stmt = gsi_stmt (gsi);
3793 : 556 : cc = lookup_cand (cc->next_interp);
3794 : : }
3795 : :
3796 : 299 : if (dump_file && (dump_flags & TDF_DETAILS))
3797 : 0 : stmt_to_print = gsi_stmt (gsi);
3798 : : }
3799 : 0 : else if (dump_file && (dump_flags & TDF_DETAILS))
3800 : 0 : fputs (" (duplicate, not actually replacing)\n", dump_file);
3801 : : }
3802 : :
3803 : 11691 : else if (cand_incr == 0)
3804 : : {
3805 : 11691 : tree lhs = gimple_assign_lhs (c->cand_stmt);
3806 : 11691 : tree lhs_type = TREE_TYPE (lhs);
3807 : 11691 : tree basis_type = TREE_TYPE (basis_name);
3808 : :
3809 : 11691 : if (types_compatible_p (lhs_type, basis_type))
3810 : : {
3811 : 11691 : gassign *copy_stmt = gimple_build_assign (lhs, basis_name);
3812 : 11691 : gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt);
3813 : 11691 : slsr_cand_t cc = lookup_cand (c->first_interp);
3814 : 11691 : gimple_set_location (copy_stmt, gimple_location (c->cand_stmt));
3815 : 11691 : gsi_replace (&gsi, copy_stmt, false);
3816 : 43462 : while (cc)
3817 : : {
3818 : 20080 : cc->cand_stmt = copy_stmt;
3819 : 20080 : cc = lookup_cand (cc->next_interp);
3820 : : }
3821 : :
3822 : 11691 : if (dump_file && (dump_flags & TDF_DETAILS))
3823 : : stmt_to_print = copy_stmt;
3824 : : }
3825 : : else
3826 : : {
3827 : 0 : gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt);
3828 : 0 : gassign *cast_stmt = gimple_build_assign (lhs, NOP_EXPR, basis_name);
3829 : 0 : slsr_cand_t cc = lookup_cand (c->first_interp);
3830 : 0 : gimple_set_location (cast_stmt, gimple_location (c->cand_stmt));
3831 : 0 : gsi_replace (&gsi, cast_stmt, false);
3832 : 0 : while (cc)
3833 : : {
3834 : 0 : cc->cand_stmt = cast_stmt;
3835 : 0 : cc = lookup_cand (cc->next_interp);
3836 : : }
3837 : :
3838 : 0 : if (dump_file && (dump_flags & TDF_DETAILS))
3839 : : stmt_to_print = cast_stmt;
3840 : : }
3841 : : }
3842 : : else
3843 : 0 : gcc_unreachable ();
3844 : :
3845 : 22552 : if (dump_file && (dump_flags & TDF_DETAILS) && stmt_to_print)
3846 : : {
3847 : 0 : fputs ("With: ", dump_file);
3848 : 0 : print_gimple_stmt (dump_file, stmt_to_print, 0);
3849 : 0 : fputs ("\n", dump_file);
3850 : : }
3851 : : }
3852 : :
3853 : : /* For each candidate in the tree rooted at C, replace it with
3854 : : an increment if such has been shown to be profitable. */
3855 : :
3856 : : static void
3857 : 54495 : replace_profitable_candidates (slsr_cand_t c, auto_bitmap &sdce_worklist)
3858 : : {
3859 : 89329 : if (!cand_already_replaced (c))
3860 : : {
3861 : 89329 : offset_int increment = cand_abs_increment (c);
3862 : 89329 : enum tree_code orig_code = gimple_assign_rhs_code (c->cand_stmt);
3863 : 89329 : int i;
3864 : :
3865 : 89329 : i = incr_vec_index (increment);
3866 : :
3867 : : /* Only process profitable increments. Nothing useful can be done
3868 : : to a cast or copy. */
3869 : 89329 : if (i >= 0
3870 : 89329 : && profitable_increment_p (i)
3871 : 87598 : && orig_code != SSA_NAME
3872 : 142506 : && !CONVERT_EXPR_CODE_P (orig_code))
3873 : : {
3874 : 22556 : if (phi_dependent_cand_p (c))
3875 : : {
3876 : 12 : gphi *phi = as_a <gphi *> (lookup_cand (c->def_phi)->cand_stmt);
3877 : :
3878 : 12 : if (all_phi_incrs_profitable (c, phi))
3879 : : {
3880 : : /* Look up the LHS SSA name from C's basis. This will be
3881 : : the RHS1 of the adds we will introduce to create new
3882 : : phi arguments. */
3883 : 8 : slsr_cand_t basis = lookup_cand (c->basis);
3884 : 8 : tree basis_name = gimple_assign_lhs (basis->cand_stmt);
3885 : :
3886 : : /* Create a new phi statement that will represent C's true
3887 : : basis after the transformation is complete. */
3888 : 8 : location_t loc = gimple_location (c->cand_stmt);
3889 : 8 : tree name = create_phi_basis (c, phi, basis_name,
3890 : : loc, UNKNOWN_STRIDE);
3891 : :
3892 : : /* Replace C with an add of the new basis phi and the
3893 : : increment. */
3894 : 8 : replace_one_candidate (c, i, name, sdce_worklist);
3895 : : }
3896 : : }
3897 : : else
3898 : : {
3899 : 22544 : slsr_cand_t basis = lookup_cand (c->basis);
3900 : 22544 : tree basis_name = gimple_assign_lhs (basis->cand_stmt);
3901 : 22544 : replace_one_candidate (c, i, basis_name, sdce_worklist);
3902 : : }
3903 : : }
3904 : : }
3905 : :
3906 : 89329 : if (c->sibling)
3907 : 2482 : replace_profitable_candidates (lookup_cand (c->sibling), sdce_worklist);
3908 : :
3909 : 89329 : if (c->dependent)
3910 : 34834 : replace_profitable_candidates (lookup_cand (c->dependent), sdce_worklist);
3911 : 54495 : }
3912 : :
3913 : : /* Analyze costs of related candidates in the candidate vector,
3914 : : and make beneficial replacements. */
3915 : :
3916 : : static void
3917 : 994204 : analyze_candidates_and_replace (void)
3918 : : {
3919 : 994204 : unsigned i;
3920 : 994204 : slsr_cand_t c;
3921 : 994204 : auto_bitmap simple_dce_worklist;
3922 : :
3923 : : /* Each candidate that has a null basis and a non-null
3924 : : dependent is the root of a tree of related statements.
3925 : : Analyze each tree to determine a subset of those
3926 : : statements that can be replaced with maximum benefit.
3927 : :
3928 : : Note the first NULL element is skipped. */
3929 : 7951020 : FOR_EACH_VEC_ELT_FROM (cand_vec, i, c, 1)
3930 : : {
3931 : 6956816 : slsr_cand_t first_dep;
3932 : :
3933 : 6956816 : if (c->basis != 0 || c->dependent == 0)
3934 : 6441158 : continue;
3935 : :
3936 : 515658 : if (dump_file && (dump_flags & TDF_DETAILS))
3937 : 7 : fprintf (dump_file, "\nProcessing dependency tree rooted at %d.\n",
3938 : : c->cand_num);
3939 : :
3940 : 515658 : first_dep = lookup_cand (c->dependent);
3941 : :
3942 : : /* If this is a chain of CAND_REFs, unconditionally replace
3943 : : each of them with a strength-reduced data reference. */
3944 : 515658 : if (c->kind == CAND_REF)
3945 : 5397 : replace_refs (c);
3946 : :
3947 : : /* If the common stride of all related candidates is a known
3948 : : constant, each candidate without a phi-dependence can be
3949 : : profitably replaced. Each replaces a multiply by a single
3950 : : add, with the possibility that a feeding add also goes dead.
3951 : : A candidate with a phi-dependence is replaced only if the
3952 : : compensation code it requires is offset by the strength
3953 : : reduction savings. */
3954 : 510261 : else if (TREE_CODE (c->stride) == INTEGER_CST)
3955 : 458248 : replace_uncond_cands_and_profitable_phis (first_dep,
3956 : : simple_dce_worklist);
3957 : :
3958 : : /* When the stride is an SSA name, it may still be profitable
3959 : : to replace some or all of the dependent candidates, depending
3960 : : on whether the introduced increments can be reused, or are
3961 : : less expensive to calculate than the replaced statements. */
3962 : : else
3963 : : {
3964 : 52013 : machine_mode mode;
3965 : 52013 : bool speed;
3966 : :
3967 : : /* Determine whether we'll be generating pointer arithmetic
3968 : : when replacing candidates. */
3969 : 104026 : address_arithmetic_p = (c->kind == CAND_ADD
3970 : 52013 : && POINTER_TYPE_P (c->cand_type));
3971 : :
3972 : : /* If all candidates have already been replaced under other
3973 : : interpretations, nothing remains to be done. */
3974 : 52013 : if (!count_candidates (c))
3975 : 0 : continue;
3976 : :
3977 : : /* Construct an array of increments for this candidate chain. */
3978 : 52013 : incr_vec = XNEWVEC (incr_info, MAX_INCR_VEC_LEN);
3979 : 52013 : incr_vec_len = 0;
3980 : 52013 : record_increments (c);
3981 : :
3982 : : /* Determine which increments are profitable to replace. */
3983 : 52013 : mode = TYPE_MODE (TREE_TYPE (gimple_assign_lhs (c->cand_stmt)));
3984 : 52013 : speed = optimize_cands_for_speed_p (c);
3985 : 52013 : analyze_increments (first_dep, mode, speed);
3986 : :
3987 : : /* Insert initializers of the form T_0 = stride * increment
3988 : : for use in profitable replacements. */
3989 : 52013 : insert_initializers (first_dep);
3990 : 52013 : dump_incr_vec ();
3991 : :
3992 : : /* Perform the replacements. */
3993 : 52013 : replace_profitable_candidates (first_dep, simple_dce_worklist);
3994 : 52013 : free (incr_vec);
3995 : : }
3996 : : }
3997 : :
3998 : : /* For conditional candidates, we may have uncommitted insertions
3999 : : on edges to clean up. */
4000 : 994204 : gsi_commit_edge_inserts ();
4001 : :
4002 : 994204 : simple_dce_from_worklist (simple_dce_worklist);
4003 : 994204 : }
4004 : :
4005 : : namespace {
4006 : :
4007 : : const pass_data pass_data_strength_reduction =
4008 : : {
4009 : : GIMPLE_PASS, /* type */
4010 : : "slsr", /* name */
4011 : : OPTGROUP_NONE, /* optinfo_flags */
4012 : : TV_GIMPLE_SLSR, /* tv_id */
4013 : : ( PROP_cfg | PROP_ssa ), /* properties_required */
4014 : : 0, /* properties_provided */
4015 : : 0, /* properties_destroyed */
4016 : : 0, /* todo_flags_start */
4017 : : 0, /* todo_flags_finish */
4018 : : };
4019 : :
4020 : : class pass_strength_reduction : public gimple_opt_pass
4021 : : {
4022 : : public:
4023 : 272708 : pass_strength_reduction (gcc::context *ctxt)
4024 : 545416 : : gimple_opt_pass (pass_data_strength_reduction, ctxt)
4025 : : {}
4026 : :
4027 : : /* opt_pass methods: */
4028 : 994218 : bool gate (function *) final override { return flag_tree_slsr; }
4029 : : unsigned int execute (function *) final override;
4030 : :
4031 : : }; // class pass_strength_reduction
4032 : :
4033 : : unsigned
4034 : 994204 : pass_strength_reduction::execute (function *fun)
4035 : : {
4036 : : /* Create the obstack where candidates will reside. */
4037 : 994204 : gcc_obstack_init (&cand_obstack);
4038 : :
4039 : : /* Allocate the candidate vector and initialize the first NULL element. */
4040 : 994204 : cand_vec.create (128);
4041 : 994204 : cand_vec.safe_push (NULL);
4042 : :
4043 : : /* Allocate the mapping from statements to candidate indices. */
4044 : 994204 : stmt_cand_map = new hash_map<gimple *, slsr_cand_t>;
4045 : :
4046 : : /* Create the obstack where candidate chains will reside. */
4047 : 994204 : gcc_obstack_init (&chain_obstack);
4048 : :
4049 : : /* Allocate the mapping from base expressions to candidate chains. */
4050 : 994204 : base_cand_map = new hash_table<cand_chain_hasher> (500);
4051 : :
4052 : : /* Allocate the mapping from bases to alternative bases. */
4053 : 994204 : alt_base_map = new hash_map<tree, tree>;
4054 : :
4055 : : /* Initialize the loop optimizer. We need to detect flow across
4056 : : back edges, and this gives us dominator information as well. */
4057 : 994204 : loop_optimizer_init (AVOID_CFG_MODIFICATIONS);
4058 : :
4059 : : /* Walk the CFG in predominator order looking for strength reduction
4060 : : candidates. */
4061 : 994204 : find_candidates_dom_walker (CDI_DOMINATORS)
4062 : 994204 : .walk (fun->cfg->x_entry_block_ptr);
4063 : :
4064 : 994204 : if (dump_file && (dump_flags & TDF_DETAILS))
4065 : : {
4066 : 3 : dump_cand_vec ();
4067 : 3 : dump_cand_chains ();
4068 : : }
4069 : :
4070 : 1988408 : delete alt_base_map;
4071 : 994204 : free_affine_expand_cache (&name_expansions);
4072 : :
4073 : : /* Analyze costs and make appropriate replacements. */
4074 : 994204 : analyze_candidates_and_replace ();
4075 : :
4076 : 994204 : loop_optimizer_finalize ();
4077 : 994204 : delete base_cand_map;
4078 : 994204 : base_cand_map = NULL;
4079 : 994204 : obstack_free (&chain_obstack, NULL);
4080 : 1988408 : delete stmt_cand_map;
4081 : 994204 : cand_vec.release ();
4082 : 994204 : obstack_free (&cand_obstack, NULL);
4083 : :
4084 : 994204 : return 0;
4085 : : }
4086 : :
4087 : : } // anon namespace
4088 : :
4089 : : gimple_opt_pass *
4090 : 272708 : make_pass_strength_reduction (gcc::context *ctxt)
4091 : : {
4092 : 272708 : return new pass_strength_reduction (ctxt);
4093 : : }
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