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f9453c07 | 1 | /* Straight-line strength reduction. |
818ab71a | 2 | Copyright (C) 2012-2016 Free Software Foundation, Inc. |
f9453c07 BS |
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 | ||
9b92d12b BS |
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. | |
f9453c07 BS |
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" | |
c7131fb2 | 39 | #include "backend.h" |
957060b5 | 40 | #include "rtl.h" |
40e23961 | 41 | #include "tree.h" |
c7131fb2 | 42 | #include "gimple.h" |
957060b5 AM |
43 | #include "cfghooks.h" |
44 | #include "tree-pass.h" | |
c7131fb2 | 45 | #include "ssa.h" |
957060b5 | 46 | #include "expmed.h" |
957060b5 | 47 | #include "gimple-pretty-print.h" |
40e23961 | 48 | #include "fold-const.h" |
5be5c238 | 49 | #include "gimple-iterator.h" |
18f429e2 | 50 | #include "gimplify-me.h" |
d8a2d370 | 51 | #include "stor-layout.h" |
f9453c07 | 52 | #include "cfgloop.h" |
442b4905 | 53 | #include "tree-cfg.h" |
f9453c07 | 54 | #include "domwalk.h" |
ccdbfe93 | 55 | #include "params.h" |
4484a35a | 56 | #include "tree-ssa-address.h" |
96d75a2c | 57 | #include "tree-affine.h" |
9b2b7279 | 58 | #include "builtins.h" |
f9453c07 BS |
59 | \f |
60 | /* Information about a strength reduction candidate. Each statement | |
61 | in the candidate table represents an expression of one of the | |
62 | following forms (the special case of CAND_REF will be described | |
63 | later): | |
64 | ||
65 | (CAND_MULT) S1: X = (B + i) * S | |
66 | (CAND_ADD) S1: X = B + (i * S) | |
67 | ||
68 | Here X and B are SSA names, i is an integer constant, and S is | |
69 | either an SSA name or a constant. We call B the "base," i the | |
70 | "index", and S the "stride." | |
71 | ||
72 | Any statement S0 that dominates S1 and is of the form: | |
73 | ||
74 | (CAND_MULT) S0: Y = (B + i') * S | |
75 | (CAND_ADD) S0: Y = B + (i' * S) | |
76 | ||
77 | is called a "basis" for S1. In both cases, S1 may be replaced by | |
78 | ||
79 | S1': X = Y + (i - i') * S, | |
80 | ||
81 | where (i - i') * S is folded to the extent possible. | |
82 | ||
83 | All gimple statements are visited in dominator order, and each | |
84 | statement that may contribute to one of the forms of S1 above is | |
85 | given at least one entry in the candidate table. Such statements | |
86 | include addition, pointer addition, subtraction, multiplication, | |
87 | negation, copies, and nontrivial type casts. If a statement may | |
88 | represent more than one expression of the forms of S1 above, | |
89 | multiple "interpretations" are stored in the table and chained | |
90 | together. Examples: | |
91 | ||
92 | * An add of two SSA names may treat either operand as the base. | |
93 | * A multiply of two SSA names, likewise. | |
94 | * A copy or cast may be thought of as either a CAND_MULT with | |
95 | i = 0 and S = 1, or as a CAND_ADD with i = 0 or S = 0. | |
96 | ||
97 | Candidate records are allocated from an obstack. They are addressed | |
98 | both from a hash table keyed on S1, and from a vector of candidate | |
99 | pointers arranged in predominator order. | |
100 | ||
101 | Opportunity note | |
102 | ---------------- | |
103 | Currently we don't recognize: | |
104 | ||
105 | S0: Y = (S * i') - B | |
106 | S1: X = (S * i) - B | |
107 | ||
108 | as a strength reduction opportunity, even though this S1 would | |
109 | also be replaceable by the S1' above. This can be added if it | |
2749c8f6 BS |
110 | comes up in practice. |
111 | ||
112 | Strength reduction in addressing | |
113 | -------------------------------- | |
114 | There is another kind of candidate known as CAND_REF. A CAND_REF | |
115 | describes a statement containing a memory reference having | |
116 | complex addressing that might benefit from strength reduction. | |
117 | Specifically, we are interested in references for which | |
118 | get_inner_reference returns a base address, offset, and bitpos as | |
119 | follows: | |
120 | ||
121 | base: MEM_REF (T1, C1) | |
122 | offset: MULT_EXPR (PLUS_EXPR (T2, C2), C3) | |
123 | bitpos: C4 * BITS_PER_UNIT | |
124 | ||
125 | Here T1 and T2 are arbitrary trees, and C1, C2, C3, C4 are | |
126 | arbitrary integer constants. Note that C2 may be zero, in which | |
127 | case the offset will be MULT_EXPR (T2, C3). | |
128 | ||
129 | When this pattern is recognized, the original memory reference | |
130 | can be replaced with: | |
131 | ||
132 | MEM_REF (POINTER_PLUS_EXPR (T1, MULT_EXPR (T2, C3)), | |
133 | C1 + (C2 * C3) + C4) | |
134 | ||
135 | which distributes the multiply to allow constant folding. When | |
136 | two or more addressing expressions can be represented by MEM_REFs | |
137 | of this form, differing only in the constants C1, C2, and C4, | |
138 | making this substitution produces more efficient addressing during | |
139 | the RTL phases. When there are not at least two expressions with | |
140 | the same values of T1, T2, and C3, there is nothing to be gained | |
141 | by the replacement. | |
142 | ||
143 | Strength reduction of CAND_REFs uses the same infrastructure as | |
144 | that used by CAND_MULTs and CAND_ADDs. We record T1 in the base (B) | |
145 | field, MULT_EXPR (T2, C3) in the stride (S) field, and | |
146 | C1 + (C2 * C3) + C4 in the index (i) field. A basis for a CAND_REF | |
147 | is thus another CAND_REF with the same B and S values. When at | |
148 | least two CAND_REFs are chained together using the basis relation, | |
149 | each of them is replaced as above, resulting in improved code | |
9b92d12b BS |
150 | generation for addressing. |
151 | ||
152 | Conditional candidates | |
153 | ====================== | |
154 | ||
155 | Conditional candidates are best illustrated with an example. | |
156 | Consider the code sequence: | |
157 | ||
158 | (1) x_0 = ...; | |
159 | (2) a_0 = x_0 * 5; MULT (B: x_0; i: 0; S: 5) | |
160 | if (...) | |
161 | (3) x_1 = x_0 + 1; ADD (B: x_0, i: 1; S: 1) | |
162 | (4) x_2 = PHI <x_0, x_1>; PHI (B: x_0, i: 0, S: 1) | |
163 | (5) x_3 = x_2 + 1; ADD (B: x_2, i: 1, S: 1) | |
164 | (6) a_1 = x_3 * 5; MULT (B: x_2, i: 1; S: 5) | |
165 | ||
166 | Here strength reduction is complicated by the uncertain value of x_2. | |
167 | A legitimate transformation is: | |
168 | ||
169 | (1) x_0 = ...; | |
170 | (2) a_0 = x_0 * 5; | |
171 | if (...) | |
172 | { | |
173 | (3) [x_1 = x_0 + 1;] | |
174 | (3a) t_1 = a_0 + 5; | |
175 | } | |
176 | (4) [x_2 = PHI <x_0, x_1>;] | |
177 | (4a) t_2 = PHI <a_0, t_1>; | |
178 | (5) [x_3 = x_2 + 1;] | |
179 | (6r) a_1 = t_2 + 5; | |
180 | ||
181 | where the bracketed instructions may go dead. | |
182 | ||
183 | To recognize this opportunity, we have to observe that statement (6) | |
184 | has a "hidden basis" (2). The hidden basis is unlike a normal basis | |
185 | in that the statement and the hidden basis have different base SSA | |
186 | names (x_2 and x_0, respectively). The relationship is established | |
187 | when a statement's base name (x_2) is defined by a phi statement (4), | |
188 | each argument of which (x_0, x_1) has an identical "derived base name." | |
189 | If the argument is defined by a candidate (as x_1 is by (3)) that is a | |
190 | CAND_ADD having a stride of 1, the derived base name of the argument is | |
191 | the base name of the candidate (x_0). Otherwise, the argument itself | |
192 | is its derived base name (as is the case with argument x_0). | |
193 | ||
194 | The hidden basis for statement (6) is the nearest dominating candidate | |
195 | whose base name is the derived base name (x_0) of the feeding phi (4), | |
196 | and whose stride is identical to that of the statement. We can then | |
197 | create the new "phi basis" (4a) and feeding adds along incoming arcs (3a), | |
198 | allowing the final replacement of (6) by the strength-reduced (6r). | |
199 | ||
200 | To facilitate this, a new kind of candidate (CAND_PHI) is introduced. | |
201 | A CAND_PHI is not a candidate for replacement, but is maintained in the | |
202 | candidate table to ease discovery of hidden bases. Any phi statement | |
203 | whose arguments share a common derived base name is entered into the | |
204 | table with the derived base name, an (arbitrary) index of zero, and a | |
205 | stride of 1. A statement with a hidden basis can then be detected by | |
206 | simply looking up its feeding phi definition in the candidate table, | |
207 | extracting the derived base name, and searching for a basis in the | |
208 | usual manner after substituting the derived base name. | |
209 | ||
210 | Note that the transformation is only valid when the original phi and | |
211 | the statements that define the phi's arguments are all at the same | |
212 | position in the loop hierarchy. */ | |
f9453c07 BS |
213 | |
214 | ||
215 | /* Index into the candidate vector, offset by 1. VECs are zero-based, | |
216 | while cand_idx's are one-based, with zero indicating null. */ | |
217 | typedef unsigned cand_idx; | |
218 | ||
219 | /* The kind of candidate. */ | |
220 | enum cand_kind | |
221 | { | |
222 | CAND_MULT, | |
2749c8f6 | 223 | CAND_ADD, |
9b92d12b BS |
224 | CAND_REF, |
225 | CAND_PHI | |
f9453c07 BS |
226 | }; |
227 | ||
228 | struct slsr_cand_d | |
229 | { | |
230 | /* The candidate statement S1. */ | |
355fe088 | 231 | gimple *cand_stmt; |
f9453c07 | 232 | |
3cfd4469 BS |
233 | /* The base expression B: often an SSA name, but not always. */ |
234 | tree base_expr; | |
f9453c07 BS |
235 | |
236 | /* The stride S. */ | |
237 | tree stride; | |
238 | ||
239 | /* The index constant i. */ | |
807e902e | 240 | widest_int index; |
f9453c07 | 241 | |
3cfd4469 | 242 | /* The type of the candidate. This is normally the type of base_expr, |
f9453c07 | 243 | but casts may have occurred when combining feeding instructions. |
2749c8f6 BS |
244 | A candidate can only be a basis for candidates of the same final type. |
245 | (For CAND_REFs, this is the type to be used for operand 1 of the | |
246 | replacement MEM_REF.) */ | |
f9453c07 BS |
247 | tree cand_type; |
248 | ||
249 | /* The kind of candidate (CAND_MULT, etc.). */ | |
250 | enum cand_kind kind; | |
251 | ||
252 | /* Index of this candidate in the candidate vector. */ | |
253 | cand_idx cand_num; | |
254 | ||
255 | /* Index of the next candidate record for the same statement. | |
256 | A statement may be useful in more than one way (e.g., due to | |
257 | commutativity). So we can have multiple "interpretations" | |
258 | of a statement. */ | |
259 | cand_idx next_interp; | |
260 | ||
261 | /* Index of the basis statement S0, if any, in the candidate vector. */ | |
262 | cand_idx basis; | |
263 | ||
264 | /* First candidate for which this candidate is a basis, if one exists. */ | |
265 | cand_idx dependent; | |
266 | ||
267 | /* Next candidate having the same basis as this one. */ | |
268 | cand_idx sibling; | |
269 | ||
9b92d12b BS |
270 | /* If this is a conditional candidate, the CAND_PHI candidate |
271 | that defines the base SSA name B. */ | |
272 | cand_idx def_phi; | |
f9453c07 BS |
273 | |
274 | /* Savings that can be expected from eliminating dead code if this | |
275 | candidate is replaced. */ | |
276 | int dead_savings; | |
277 | }; | |
278 | ||
279 | typedef struct slsr_cand_d slsr_cand, *slsr_cand_t; | |
280 | typedef const struct slsr_cand_d *const_slsr_cand_t; | |
281 | ||
282 | /* Pointers to candidates are chained together as part of a mapping | |
3cfd4469 | 283 | from base expressions to the candidates that use them. */ |
f9453c07 BS |
284 | |
285 | struct cand_chain_d | |
286 | { | |
3cfd4469 BS |
287 | /* Base expression for the chain of candidates: often, but not |
288 | always, an SSA name. */ | |
289 | tree base_expr; | |
f9453c07 BS |
290 | |
291 | /* Pointer to a candidate. */ | |
292 | slsr_cand_t cand; | |
293 | ||
294 | /* Chain pointer. */ | |
295 | struct cand_chain_d *next; | |
296 | ||
297 | }; | |
298 | ||
299 | typedef struct cand_chain_d cand_chain, *cand_chain_t; | |
300 | typedef const struct cand_chain_d *const_cand_chain_t; | |
301 | ||
88ca9ea1 BS |
302 | /* Information about a unique "increment" associated with candidates |
303 | having an SSA name for a stride. An increment is the difference | |
304 | between the index of the candidate and the index of its basis, | |
305 | i.e., (i - i') as discussed in the module commentary. | |
306 | ||
307 | When we are not going to generate address arithmetic we treat | |
308 | increments that differ only in sign as the same, allowing sharing | |
309 | of the cost of initializers. The absolute value of the increment | |
310 | is stored in the incr_info. */ | |
311 | ||
312 | struct incr_info_d | |
313 | { | |
314 | /* The increment that relates a candidate to its basis. */ | |
807e902e | 315 | widest_int incr; |
88ca9ea1 BS |
316 | |
317 | /* How many times the increment occurs in the candidate tree. */ | |
318 | unsigned count; | |
319 | ||
320 | /* Cost of replacing candidates using this increment. Negative and | |
321 | zero costs indicate replacement should be performed. */ | |
322 | int cost; | |
323 | ||
324 | /* If this increment is profitable but is not -1, 0, or 1, it requires | |
325 | an initializer T_0 = stride * incr to be found or introduced in the | |
326 | nearest common dominator of all candidates. This field holds T_0 | |
327 | for subsequent use. */ | |
328 | tree initializer; | |
329 | ||
330 | /* If the initializer was found to already exist, this is the block | |
331 | where it was found. */ | |
332 | basic_block init_bb; | |
333 | }; | |
334 | ||
335 | typedef struct incr_info_d incr_info, *incr_info_t; | |
336 | ||
f9453c07 BS |
337 | /* Candidates are maintained in a vector. If candidate X dominates |
338 | candidate Y, then X appears before Y in the vector; but the | |
339 | converse does not necessarily hold. */ | |
9771b263 | 340 | static vec<slsr_cand_t> cand_vec; |
f9453c07 BS |
341 | |
342 | enum cost_consts | |
343 | { | |
344 | COST_NEUTRAL = 0, | |
345 | COST_INFINITE = 1000 | |
346 | }; | |
347 | ||
9b92d12b BS |
348 | enum stride_status |
349 | { | |
350 | UNKNOWN_STRIDE = 0, | |
351 | KNOWN_STRIDE = 1 | |
352 | }; | |
353 | ||
354 | enum phi_adjust_status | |
355 | { | |
356 | NOT_PHI_ADJUST = 0, | |
357 | PHI_ADJUST = 1 | |
358 | }; | |
359 | ||
360 | enum count_phis_status | |
361 | { | |
362 | DONT_COUNT_PHIS = 0, | |
363 | COUNT_PHIS = 1 | |
364 | }; | |
365 | ||
f9453c07 | 366 | /* Pointer map embodying a mapping from statements to candidates. */ |
355fe088 | 367 | static hash_map<gimple *, slsr_cand_t> *stmt_cand_map; |
f9453c07 BS |
368 | |
369 | /* Obstack for candidates. */ | |
370 | static struct obstack cand_obstack; | |
371 | ||
f9453c07 BS |
372 | /* Obstack for candidate chains. */ |
373 | static struct obstack chain_obstack; | |
88ca9ea1 BS |
374 | |
375 | /* An array INCR_VEC of incr_infos is used during analysis of related | |
376 | candidates having an SSA name for a stride. INCR_VEC_LEN describes | |
7bf55a70 BS |
377 | its current length. MAX_INCR_VEC_LEN is used to avoid costly |
378 | pathological cases. */ | |
88ca9ea1 BS |
379 | static incr_info_t incr_vec; |
380 | static unsigned incr_vec_len; | |
7bf55a70 | 381 | const int MAX_INCR_VEC_LEN = 16; |
88ca9ea1 BS |
382 | |
383 | /* For a chain of candidates with unknown stride, indicates whether or not | |
384 | we must generate pointer arithmetic when replacing statements. */ | |
385 | static bool address_arithmetic_p; | |
9b92d12b BS |
386 | |
387 | /* Forward function declarations. */ | |
388 | static slsr_cand_t base_cand_from_table (tree); | |
a7a7d10e | 389 | static tree introduce_cast_before_cand (slsr_cand_t, tree, tree); |
0916f876 | 390 | static bool legal_cast_p_1 (tree, tree); |
f9453c07 BS |
391 | \f |
392 | /* Produce a pointer to the IDX'th candidate in the candidate vector. */ | |
393 | ||
394 | static slsr_cand_t | |
395 | lookup_cand (cand_idx idx) | |
396 | { | |
9771b263 | 397 | return cand_vec[idx - 1]; |
f9453c07 BS |
398 | } |
399 | ||
4a8fb1a1 | 400 | /* Helper for hashing a candidate chain header. */ |
2749c8f6 | 401 | |
8d67ee55 | 402 | struct cand_chain_hasher : nofree_ptr_hash <cand_chain> |
2749c8f6 | 403 | { |
67f58944 TS |
404 | static inline hashval_t hash (const cand_chain *); |
405 | static inline bool equal (const cand_chain *, const cand_chain *); | |
4a8fb1a1 | 406 | }; |
2749c8f6 | 407 | |
4a8fb1a1 | 408 | inline hashval_t |
67f58944 | 409 | cand_chain_hasher::hash (const cand_chain *p) |
2749c8f6 | 410 | { |
4a8fb1a1 LC |
411 | tree base_expr = p->base_expr; |
412 | return iterative_hash_expr (base_expr, 0); | |
2749c8f6 BS |
413 | } |
414 | ||
4a8fb1a1 | 415 | inline bool |
67f58944 | 416 | cand_chain_hasher::equal (const cand_chain *chain1, const cand_chain *chain2) |
2749c8f6 | 417 | { |
3cfd4469 | 418 | return operand_equal_p (chain1->base_expr, chain2->base_expr, 0); |
2749c8f6 | 419 | } |
4a8fb1a1 LC |
420 | |
421 | /* Hash table embodying a mapping from base exprs to chains of candidates. */ | |
c203e8a7 | 422 | static hash_table<cand_chain_hasher> *base_cand_map; |
2749c8f6 | 423 | \f |
96d75a2c | 424 | /* Pointer map used by tree_to_aff_combination_expand. */ |
39c8aaa4 | 425 | static hash_map<tree, name_expansion *> *name_expansions; |
96d75a2c | 426 | /* Pointer map embodying a mapping from bases to alternative bases. */ |
b787e7a2 | 427 | static hash_map<tree, tree> *alt_base_map; |
96d75a2c YZ |
428 | |
429 | /* Given BASE, use the tree affine combiniation facilities to | |
430 | find the underlying tree expression for BASE, with any | |
8fde427f YZ |
431 | immediate offset excluded. |
432 | ||
433 | N.B. we should eliminate this backtracking with better forward | |
434 | analysis in a future release. */ | |
96d75a2c YZ |
435 | |
436 | static tree | |
437 | get_alternative_base (tree base) | |
438 | { | |
b787e7a2 | 439 | tree *result = alt_base_map->get (base); |
96d75a2c YZ |
440 | |
441 | if (result == NULL) | |
442 | { | |
443 | tree expr; | |
444 | aff_tree aff; | |
445 | ||
446 | tree_to_aff_combination_expand (base, TREE_TYPE (base), | |
447 | &aff, &name_expansions); | |
807e902e | 448 | aff.offset = 0; |
96d75a2c YZ |
449 | expr = aff_combination_to_tree (&aff); |
450 | ||
b787e7a2 | 451 | gcc_assert (!alt_base_map->put (base, base == expr ? NULL : expr)); |
96d75a2c | 452 | |
b787e7a2 | 453 | return expr == base ? NULL : expr; |
96d75a2c YZ |
454 | } |
455 | ||
456 | return *result; | |
457 | } | |
458 | ||
9b92d12b | 459 | /* Look in the candidate table for a CAND_PHI that defines BASE and |
8b28cf47 | 460 | return it if found; otherwise return NULL. */ |
f9453c07 | 461 | |
9b92d12b | 462 | static cand_idx |
8b28cf47 | 463 | find_phi_def (tree base) |
9b92d12b BS |
464 | { |
465 | slsr_cand_t c; | |
466 | ||
467 | if (TREE_CODE (base) != SSA_NAME) | |
468 | return 0; | |
29105868 | 469 | |
9b92d12b BS |
470 | c = base_cand_from_table (base); |
471 | ||
472 | if (!c || c->kind != CAND_PHI) | |
473 | return 0; | |
474 | ||
475 | return c->cand_num; | |
476 | } | |
477 | ||
478 | /* Helper routine for find_basis_for_candidate. May be called twice: | |
96d75a2c YZ |
479 | once for the candidate's base expr, and optionally again either for |
480 | the candidate's phi definition or for a CAND_REF's alternative base | |
481 | expression. */ | |
9b92d12b BS |
482 | |
483 | static slsr_cand_t | |
484 | find_basis_for_base_expr (slsr_cand_t c, tree base_expr) | |
f9453c07 | 485 | { |
2749c8f6 | 486 | cand_chain mapping_key; |
f9453c07 BS |
487 | cand_chain_t chain; |
488 | slsr_cand_t basis = NULL; | |
489 | ||
ccdbfe93 BS |
490 | // Limit potential of N^2 behavior for long candidate chains. |
491 | int iters = 0; | |
492 | int max_iters = PARAM_VALUE (PARAM_MAX_SLSR_CANDIDATE_SCAN); | |
493 | ||
9b92d12b | 494 | mapping_key.base_expr = base_expr; |
c203e8a7 | 495 | chain = base_cand_map->find (&mapping_key); |
f9453c07 | 496 | |
ccdbfe93 | 497 | for (; chain && iters < max_iters; chain = chain->next, ++iters) |
f9453c07 BS |
498 | { |
499 | slsr_cand_t one_basis = chain->cand; | |
500 | ||
501 | if (one_basis->kind != c->kind | |
69e1a1a3 | 502 | || one_basis->cand_stmt == c->cand_stmt |
f9453c07 BS |
503 | || !operand_equal_p (one_basis->stride, c->stride, 0) |
504 | || !types_compatible_p (one_basis->cand_type, c->cand_type) | |
505 | || !dominated_by_p (CDI_DOMINATORS, | |
506 | gimple_bb (c->cand_stmt), | |
507 | gimple_bb (one_basis->cand_stmt))) | |
508 | continue; | |
509 | ||
510 | if (!basis || basis->cand_num < one_basis->cand_num) | |
511 | basis = one_basis; | |
512 | } | |
513 | ||
9b92d12b BS |
514 | return basis; |
515 | } | |
516 | ||
517 | /* Use the base expr from candidate C to look for possible candidates | |
518 | that can serve as a basis for C. Each potential basis must also | |
519 | appear in a block that dominates the candidate statement and have | |
520 | the same stride and type. If more than one possible basis exists, | |
521 | the one with highest index in the vector is chosen; this will be | |
522 | the most immediately dominating basis. */ | |
523 | ||
524 | static int | |
525 | find_basis_for_candidate (slsr_cand_t c) | |
526 | { | |
527 | slsr_cand_t basis = find_basis_for_base_expr (c, c->base_expr); | |
528 | ||
529 | /* If a candidate doesn't have a basis using its base expression, | |
530 | it may have a basis hidden by one or more intervening phis. */ | |
531 | if (!basis && c->def_phi) | |
532 | { | |
533 | basic_block basis_bb, phi_bb; | |
534 | slsr_cand_t phi_cand = lookup_cand (c->def_phi); | |
535 | basis = find_basis_for_base_expr (c, phi_cand->base_expr); | |
536 | ||
537 | if (basis) | |
538 | { | |
539 | /* A hidden basis must dominate the phi-definition of the | |
540 | candidate's base name. */ | |
541 | phi_bb = gimple_bb (phi_cand->cand_stmt); | |
542 | basis_bb = gimple_bb (basis->cand_stmt); | |
543 | ||
544 | if (phi_bb == basis_bb | |
545 | || !dominated_by_p (CDI_DOMINATORS, phi_bb, basis_bb)) | |
546 | { | |
547 | basis = NULL; | |
548 | c->basis = 0; | |
549 | } | |
550 | ||
551 | /* If we found a hidden basis, estimate additional dead-code | |
552 | savings if the phi and its feeding statements can be removed. */ | |
553 | if (basis && has_single_use (gimple_phi_result (phi_cand->cand_stmt))) | |
554 | c->dead_savings += phi_cand->dead_savings; | |
555 | } | |
556 | } | |
557 | ||
8fde427f | 558 | if (flag_expensive_optimizations && !basis && c->kind == CAND_REF) |
96d75a2c YZ |
559 | { |
560 | tree alt_base_expr = get_alternative_base (c->base_expr); | |
561 | if (alt_base_expr) | |
562 | basis = find_basis_for_base_expr (c, alt_base_expr); | |
563 | } | |
564 | ||
f9453c07 BS |
565 | if (basis) |
566 | { | |
567 | c->sibling = basis->dependent; | |
568 | basis->dependent = c->cand_num; | |
569 | return basis->cand_num; | |
570 | } | |
571 | ||
572 | return 0; | |
573 | } | |
574 | ||
96d75a2c YZ |
575 | /* Record a mapping from BASE to C, indicating that C may potentially serve |
576 | as a basis using that base expression. BASE may be the same as | |
577 | C->BASE_EXPR; alternatively BASE can be a different tree that share the | |
578 | underlining expression of C->BASE_EXPR. */ | |
f9453c07 BS |
579 | |
580 | static void | |
96d75a2c | 581 | record_potential_basis (slsr_cand_t c, tree base) |
f9453c07 | 582 | { |
2749c8f6 | 583 | cand_chain_t node; |
4a8fb1a1 | 584 | cand_chain **slot; |
f9453c07 | 585 | |
96d75a2c YZ |
586 | gcc_assert (base); |
587 | ||
f9453c07 | 588 | node = (cand_chain_t) obstack_alloc (&chain_obstack, sizeof (cand_chain)); |
96d75a2c | 589 | node->base_expr = base; |
f9453c07 BS |
590 | node->cand = c; |
591 | node->next = NULL; | |
c203e8a7 | 592 | slot = base_cand_map->find_slot (node, INSERT); |
f9453c07 | 593 | |
2749c8f6 | 594 | if (*slot) |
f9453c07 | 595 | { |
2749c8f6 | 596 | cand_chain_t head = (cand_chain_t) (*slot); |
f9453c07 BS |
597 | node->next = head->next; |
598 | head->next = node; | |
599 | } | |
600 | else | |
2749c8f6 | 601 | *slot = node; |
f9453c07 BS |
602 | } |
603 | ||
604 | /* Allocate storage for a new candidate and initialize its fields. | |
96d75a2c YZ |
605 | Attempt to find a basis for the candidate. |
606 | ||
607 | For CAND_REF, an alternative base may also be recorded and used | |
608 | to find a basis. This helps cases where the expression hidden | |
609 | behind BASE (which is usually an SSA_NAME) has immediate offset, | |
610 | e.g. | |
611 | ||
612 | a2[i][j] = 1; | |
613 | a2[i + 20][j] = 2; */ | |
f9453c07 BS |
614 | |
615 | static slsr_cand_t | |
355fe088 | 616 | alloc_cand_and_find_basis (enum cand_kind kind, gimple *gs, tree base, |
807e902e | 617 | const widest_int &index, tree stride, tree ctype, |
f9453c07 BS |
618 | unsigned savings) |
619 | { | |
620 | slsr_cand_t c = (slsr_cand_t) obstack_alloc (&cand_obstack, | |
621 | sizeof (slsr_cand)); | |
622 | c->cand_stmt = gs; | |
3cfd4469 | 623 | c->base_expr = base; |
f9453c07 BS |
624 | c->stride = stride; |
625 | c->index = index; | |
626 | c->cand_type = ctype; | |
627 | c->kind = kind; | |
9771b263 | 628 | c->cand_num = cand_vec.length () + 1; |
f9453c07 BS |
629 | c->next_interp = 0; |
630 | c->dependent = 0; | |
631 | c->sibling = 0; | |
8b28cf47 | 632 | c->def_phi = kind == CAND_MULT ? find_phi_def (base) : 0; |
f9453c07 BS |
633 | c->dead_savings = savings; |
634 | ||
9771b263 | 635 | cand_vec.safe_push (c); |
9b92d12b BS |
636 | |
637 | if (kind == CAND_PHI) | |
638 | c->basis = 0; | |
639 | else | |
640 | c->basis = find_basis_for_candidate (c); | |
641 | ||
96d75a2c | 642 | record_potential_basis (c, base); |
8fde427f | 643 | if (flag_expensive_optimizations && kind == CAND_REF) |
96d75a2c YZ |
644 | { |
645 | tree alt_base = get_alternative_base (base); | |
646 | if (alt_base) | |
647 | record_potential_basis (c, alt_base); | |
648 | } | |
f9453c07 BS |
649 | |
650 | return c; | |
651 | } | |
652 | ||
653 | /* Determine the target cost of statement GS when compiling according | |
654 | to SPEED. */ | |
655 | ||
656 | static int | |
355fe088 | 657 | stmt_cost (gimple *gs, bool speed) |
f9453c07 BS |
658 | { |
659 | tree lhs, rhs1, rhs2; | |
ef4bddc2 | 660 | machine_mode lhs_mode; |
f9453c07 BS |
661 | |
662 | gcc_assert (is_gimple_assign (gs)); | |
663 | lhs = gimple_assign_lhs (gs); | |
664 | rhs1 = gimple_assign_rhs1 (gs); | |
665 | lhs_mode = TYPE_MODE (TREE_TYPE (lhs)); | |
666 | ||
667 | switch (gimple_assign_rhs_code (gs)) | |
668 | { | |
669 | case MULT_EXPR: | |
670 | rhs2 = gimple_assign_rhs2 (gs); | |
671 | ||
9541ffee | 672 | if (tree_fits_shwi_p (rhs2)) |
eb1ce453 | 673 | return mult_by_coeff_cost (tree_to_shwi (rhs2), lhs_mode, speed); |
f9453c07 BS |
674 | |
675 | gcc_assert (TREE_CODE (rhs1) != INTEGER_CST); | |
5322d07e | 676 | return mul_cost (speed, lhs_mode); |
f9453c07 BS |
677 | |
678 | case PLUS_EXPR: | |
679 | case POINTER_PLUS_EXPR: | |
680 | case MINUS_EXPR: | |
5322d07e | 681 | return add_cost (speed, lhs_mode); |
f9453c07 BS |
682 | |
683 | case NEGATE_EXPR: | |
5322d07e | 684 | return neg_cost (speed, lhs_mode); |
f9453c07 | 685 | |
d822570f | 686 | CASE_CONVERT: |
6dd8f4bb | 687 | return convert_cost (lhs_mode, TYPE_MODE (TREE_TYPE (rhs1)), speed); |
f9453c07 BS |
688 | |
689 | /* Note that we don't assign costs to copies that in most cases | |
690 | will go away. */ | |
691 | default: | |
692 | ; | |
693 | } | |
694 | ||
695 | gcc_unreachable (); | |
696 | return 0; | |
697 | } | |
698 | ||
699 | /* Look up the defining statement for BASE_IN and return a pointer | |
700 | to its candidate in the candidate table, if any; otherwise NULL. | |
701 | Only CAND_ADD and CAND_MULT candidates are returned. */ | |
702 | ||
703 | static slsr_cand_t | |
704 | base_cand_from_table (tree base_in) | |
705 | { | |
706 | slsr_cand_t *result; | |
707 | ||
355fe088 | 708 | gimple *def = SSA_NAME_DEF_STMT (base_in); |
f9453c07 BS |
709 | if (!def) |
710 | return (slsr_cand_t) NULL; | |
711 | ||
b787e7a2 | 712 | result = stmt_cand_map->get (def); |
2749c8f6 BS |
713 | |
714 | if (result && (*result)->kind != CAND_REF) | |
715 | return *result; | |
f9453c07 | 716 | |
2749c8f6 | 717 | return (slsr_cand_t) NULL; |
f9453c07 BS |
718 | } |
719 | ||
720 | /* Add an entry to the statement-to-candidate mapping. */ | |
721 | ||
722 | static void | |
355fe088 | 723 | add_cand_for_stmt (gimple *gs, slsr_cand_t c) |
f9453c07 | 724 | { |
b787e7a2 | 725 | gcc_assert (!stmt_cand_map->put (gs, c)); |
f9453c07 BS |
726 | } |
727 | \f | |
9b92d12b BS |
728 | /* Given PHI which contains a phi statement, determine whether it |
729 | satisfies all the requirements of a phi candidate. If so, create | |
730 | a candidate. Note that a CAND_PHI never has a basis itself, but | |
731 | is used to help find a basis for subsequent candidates. */ | |
732 | ||
733 | static void | |
538dd0b7 | 734 | slsr_process_phi (gphi *phi, bool speed) |
9b92d12b BS |
735 | { |
736 | unsigned i; | |
737 | tree arg0_base = NULL_TREE, base_type; | |
738 | slsr_cand_t c; | |
739 | struct loop *cand_loop = gimple_bb (phi)->loop_father; | |
740 | unsigned savings = 0; | |
741 | ||
742 | /* A CAND_PHI requires each of its arguments to have the same | |
743 | derived base name. (See the module header commentary for a | |
744 | definition of derived base names.) Furthermore, all feeding | |
745 | definitions must be in the same position in the loop hierarchy | |
746 | as PHI. */ | |
747 | ||
748 | for (i = 0; i < gimple_phi_num_args (phi); i++) | |
749 | { | |
750 | slsr_cand_t arg_cand; | |
751 | tree arg = gimple_phi_arg_def (phi, i); | |
752 | tree derived_base_name = NULL_TREE; | |
355fe088 | 753 | gimple *arg_stmt = NULL; |
9b92d12b BS |
754 | basic_block arg_bb = NULL; |
755 | ||
756 | if (TREE_CODE (arg) != SSA_NAME) | |
757 | return; | |
758 | ||
759 | arg_cand = base_cand_from_table (arg); | |
760 | ||
761 | if (arg_cand) | |
762 | { | |
763 | while (arg_cand->kind != CAND_ADD && arg_cand->kind != CAND_PHI) | |
764 | { | |
765 | if (!arg_cand->next_interp) | |
766 | return; | |
767 | ||
768 | arg_cand = lookup_cand (arg_cand->next_interp); | |
769 | } | |
770 | ||
771 | if (!integer_onep (arg_cand->stride)) | |
772 | return; | |
773 | ||
774 | derived_base_name = arg_cand->base_expr; | |
775 | arg_stmt = arg_cand->cand_stmt; | |
776 | arg_bb = gimple_bb (arg_stmt); | |
777 | ||
778 | /* Gather potential dead code savings if the phi statement | |
779 | can be removed later on. */ | |
780 | if (has_single_use (arg)) | |
781 | { | |
782 | if (gimple_code (arg_stmt) == GIMPLE_PHI) | |
783 | savings += arg_cand->dead_savings; | |
784 | else | |
785 | savings += stmt_cost (arg_stmt, speed); | |
786 | } | |
787 | } | |
6e281ce3 | 788 | else if (SSA_NAME_IS_DEFAULT_DEF (arg)) |
9b92d12b BS |
789 | { |
790 | derived_base_name = arg; | |
6e281ce3 | 791 | arg_bb = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
9b92d12b BS |
792 | } |
793 | ||
794 | if (!arg_bb || arg_bb->loop_father != cand_loop) | |
795 | return; | |
796 | ||
797 | if (i == 0) | |
798 | arg0_base = derived_base_name; | |
799 | else if (!operand_equal_p (derived_base_name, arg0_base, 0)) | |
800 | return; | |
801 | } | |
802 | ||
803 | /* Create the candidate. "alloc_cand_and_find_basis" is named | |
804 | misleadingly for this case, as no basis will be sought for a | |
805 | CAND_PHI. */ | |
806 | base_type = TREE_TYPE (arg0_base); | |
807 | ||
807e902e KZ |
808 | c = alloc_cand_and_find_basis (CAND_PHI, phi, arg0_base, |
809 | 0, integer_one_node, base_type, savings); | |
9b92d12b BS |
810 | |
811 | /* Add the candidate to the statement-candidate mapping. */ | |
812 | add_cand_for_stmt (phi, c); | |
813 | } | |
814 | ||
c068654b BC |
815 | /* Given PBASE which is a pointer to tree, look up the defining |
816 | statement for it and check whether the candidate is in the | |
817 | form of: | |
818 | ||
819 | X = B + (1 * S), S is integer constant | |
820 | X = B + (i * S), S is integer one | |
821 | ||
822 | If so, set PBASE to the candidate's base_expr and return double | |
823 | int (i * S). | |
824 | Otherwise, just return double int zero. */ | |
825 | ||
807e902e | 826 | static widest_int |
c068654b BC |
827 | backtrace_base_for_ref (tree *pbase) |
828 | { | |
829 | tree base_in = *pbase; | |
830 | slsr_cand_t base_cand; | |
831 | ||
832 | STRIP_NOPS (base_in); | |
0916f876 YZ |
833 | |
834 | /* Strip off widening conversion(s) to handle cases where | |
835 | e.g. 'B' is widened from an 'int' in order to calculate | |
836 | a 64-bit address. */ | |
837 | if (CONVERT_EXPR_P (base_in) | |
838 | && legal_cast_p_1 (base_in, TREE_OPERAND (base_in, 0))) | |
839 | base_in = get_unwidened (base_in, NULL_TREE); | |
840 | ||
c068654b | 841 | if (TREE_CODE (base_in) != SSA_NAME) |
807e902e | 842 | return 0; |
c068654b BC |
843 | |
844 | base_cand = base_cand_from_table (base_in); | |
845 | ||
846 | while (base_cand && base_cand->kind != CAND_PHI) | |
847 | { | |
848 | if (base_cand->kind == CAND_ADD | |
807e902e | 849 | && base_cand->index == 1 |
c068654b BC |
850 | && TREE_CODE (base_cand->stride) == INTEGER_CST) |
851 | { | |
852 | /* X = B + (1 * S), S is integer constant. */ | |
853 | *pbase = base_cand->base_expr; | |
807e902e | 854 | return wi::to_widest (base_cand->stride); |
c068654b BC |
855 | } |
856 | else if (base_cand->kind == CAND_ADD | |
857 | && TREE_CODE (base_cand->stride) == INTEGER_CST | |
858 | && integer_onep (base_cand->stride)) | |
1d2151c6 | 859 | { |
c068654b BC |
860 | /* X = B + (i * S), S is integer one. */ |
861 | *pbase = base_cand->base_expr; | |
862 | return base_cand->index; | |
863 | } | |
864 | ||
865 | if (base_cand->next_interp) | |
866 | base_cand = lookup_cand (base_cand->next_interp); | |
867 | else | |
868 | base_cand = NULL; | |
869 | } | |
870 | ||
807e902e | 871 | return 0; |
c068654b BC |
872 | } |
873 | ||
2749c8f6 BS |
874 | /* Look for the following pattern: |
875 | ||
876 | *PBASE: MEM_REF (T1, C1) | |
877 | ||
878 | *POFFSET: MULT_EXPR (T2, C3) [C2 is zero] | |
879 | or | |
880 | MULT_EXPR (PLUS_EXPR (T2, C2), C3) | |
881 | or | |
882 | MULT_EXPR (MINUS_EXPR (T2, -C2), C3) | |
883 | ||
884 | *PINDEX: C4 * BITS_PER_UNIT | |
885 | ||
886 | If not present, leave the input values unchanged and return FALSE. | |
887 | Otherwise, modify the input values as follows and return TRUE: | |
888 | ||
889 | *PBASE: T1 | |
890 | *POFFSET: MULT_EXPR (T2, C3) | |
c068654b BC |
891 | *PINDEX: C1 + (C2 * C3) + C4 |
892 | ||
893 | When T2 is recorded by a CAND_ADD in the form of (T2' + C5), it | |
894 | will be further restructured to: | |
895 | ||
896 | *PBASE: T1 | |
897 | *POFFSET: MULT_EXPR (T2', C3) | |
898 | *PINDEX: C1 + (C2 * C3) + C4 + (C5 * C3) */ | |
2749c8f6 BS |
899 | |
900 | static bool | |
807e902e | 901 | restructure_reference (tree *pbase, tree *poffset, widest_int *pindex, |
2749c8f6 BS |
902 | tree *ptype) |
903 | { | |
904 | tree base = *pbase, offset = *poffset; | |
807e902e KZ |
905 | widest_int index = *pindex; |
906 | tree mult_op0, t1, t2, type; | |
907 | widest_int c1, c2, c3, c4, c5; | |
2749c8f6 BS |
908 | |
909 | if (!base | |
910 | || !offset | |
911 | || TREE_CODE (base) != MEM_REF | |
912 | || TREE_CODE (offset) != MULT_EXPR | |
913 | || TREE_CODE (TREE_OPERAND (offset, 1)) != INTEGER_CST | |
807e902e | 914 | || wi::umod_floor (index, BITS_PER_UNIT) != 0) |
2749c8f6 BS |
915 | return false; |
916 | ||
917 | t1 = TREE_OPERAND (base, 0); | |
807e902e | 918 | c1 = widest_int::from (mem_ref_offset (base), SIGNED); |
2749c8f6 BS |
919 | type = TREE_TYPE (TREE_OPERAND (base, 1)); |
920 | ||
921 | mult_op0 = TREE_OPERAND (offset, 0); | |
807e902e | 922 | c3 = wi::to_widest (TREE_OPERAND (offset, 1)); |
2749c8f6 BS |
923 | |
924 | if (TREE_CODE (mult_op0) == PLUS_EXPR) | |
925 | ||
926 | if (TREE_CODE (TREE_OPERAND (mult_op0, 1)) == INTEGER_CST) | |
927 | { | |
928 | t2 = TREE_OPERAND (mult_op0, 0); | |
807e902e | 929 | c2 = wi::to_widest (TREE_OPERAND (mult_op0, 1)); |
2749c8f6 BS |
930 | } |
931 | else | |
932 | return false; | |
933 | ||
934 | else if (TREE_CODE (mult_op0) == MINUS_EXPR) | |
935 | ||
936 | if (TREE_CODE (TREE_OPERAND (mult_op0, 1)) == INTEGER_CST) | |
937 | { | |
938 | t2 = TREE_OPERAND (mult_op0, 0); | |
807e902e | 939 | c2 = -wi::to_widest (TREE_OPERAND (mult_op0, 1)); |
2749c8f6 BS |
940 | } |
941 | else | |
942 | return false; | |
943 | ||
944 | else | |
945 | { | |
946 | t2 = mult_op0; | |
807e902e | 947 | c2 = 0; |
2749c8f6 BS |
948 | } |
949 | ||
8de73453 | 950 | c4 = index >> LOG2_BITS_PER_UNIT; |
c068654b | 951 | c5 = backtrace_base_for_ref (&t2); |
2749c8f6 BS |
952 | |
953 | *pbase = t1; | |
c068654b | 954 | *poffset = fold_build2 (MULT_EXPR, sizetype, fold_convert (sizetype, t2), |
807e902e | 955 | wide_int_to_tree (sizetype, c3)); |
c068654b | 956 | *pindex = c1 + c2 * c3 + c4 + c5 * c3; |
2749c8f6 BS |
957 | *ptype = type; |
958 | ||
959 | return true; | |
960 | } | |
961 | ||
962 | /* Given GS which contains a data reference, create a CAND_REF entry in | |
963 | the candidate table and attempt to find a basis. */ | |
964 | ||
965 | static void | |
355fe088 | 966 | slsr_process_ref (gimple *gs) |
2749c8f6 BS |
967 | { |
968 | tree ref_expr, base, offset, type; | |
969 | HOST_WIDE_INT bitsize, bitpos; | |
ef4bddc2 | 970 | machine_mode mode; |
ee45a32d | 971 | int unsignedp, reversep, volatilep; |
2749c8f6 BS |
972 | slsr_cand_t c; |
973 | ||
974 | if (gimple_vdef (gs)) | |
975 | ref_expr = gimple_assign_lhs (gs); | |
976 | else | |
977 | ref_expr = gimple_assign_rhs1 (gs); | |
978 | ||
979 | if (!handled_component_p (ref_expr) | |
980 | || TREE_CODE (ref_expr) == BIT_FIELD_REF | |
981 | || (TREE_CODE (ref_expr) == COMPONENT_REF | |
982 | && DECL_BIT_FIELD (TREE_OPERAND (ref_expr, 1)))) | |
983 | return; | |
984 | ||
985 | base = get_inner_reference (ref_expr, &bitsize, &bitpos, &offset, &mode, | |
25b75a48 | 986 | &unsignedp, &reversep, &volatilep); |
ee45a32d EB |
987 | if (reversep) |
988 | return; | |
807e902e | 989 | widest_int index = bitpos; |
2749c8f6 BS |
990 | |
991 | if (!restructure_reference (&base, &offset, &index, &type)) | |
992 | return; | |
993 | ||
994 | c = alloc_cand_and_find_basis (CAND_REF, gs, base, index, offset, | |
995 | type, 0); | |
996 | ||
997 | /* Add the candidate to the statement-candidate mapping. */ | |
998 | add_cand_for_stmt (gs, c); | |
999 | } | |
1000 | ||
f9453c07 BS |
1001 | /* Create a candidate entry for a statement GS, where GS multiplies |
1002 | two SSA names BASE_IN and STRIDE_IN. Propagate any known information | |
1003 | about the two SSA names into the new candidate. Return the new | |
1004 | candidate. */ | |
1005 | ||
1006 | static slsr_cand_t | |
355fe088 | 1007 | create_mul_ssa_cand (gimple *gs, tree base_in, tree stride_in, bool speed) |
f9453c07 BS |
1008 | { |
1009 | tree base = NULL_TREE, stride = NULL_TREE, ctype = NULL_TREE; | |
807e902e | 1010 | widest_int index; |
f9453c07 BS |
1011 | unsigned savings = 0; |
1012 | slsr_cand_t c; | |
1013 | slsr_cand_t base_cand = base_cand_from_table (base_in); | |
1014 | ||
1015 | /* Look at all interpretations of the base candidate, if necessary, | |
1016 | to find information to propagate into this candidate. */ | |
9b92d12b | 1017 | while (base_cand && !base && base_cand->kind != CAND_PHI) |
f9453c07 BS |
1018 | { |
1019 | ||
9b92d12b | 1020 | if (base_cand->kind == CAND_MULT && integer_onep (base_cand->stride)) |
f9453c07 BS |
1021 | { |
1022 | /* Y = (B + i') * 1 | |
1023 | X = Y * Z | |
1024 | ================ | |
1025 | X = (B + i') * Z */ | |
3cfd4469 | 1026 | base = base_cand->base_expr; |
f9453c07 BS |
1027 | index = base_cand->index; |
1028 | stride = stride_in; | |
1029 | ctype = base_cand->cand_type; | |
1030 | if (has_single_use (base_in)) | |
1031 | savings = (base_cand->dead_savings | |
1032 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1033 | } | |
1034 | else if (base_cand->kind == CAND_ADD | |
1035 | && TREE_CODE (base_cand->stride) == INTEGER_CST) | |
1036 | { | |
1037 | /* Y = B + (i' * S), S constant | |
1038 | X = Y * Z | |
1039 | ============================ | |
1040 | X = B + ((i' * S) * Z) */ | |
3cfd4469 | 1041 | base = base_cand->base_expr; |
807e902e | 1042 | index = base_cand->index * wi::to_widest (base_cand->stride); |
f9453c07 BS |
1043 | stride = stride_in; |
1044 | ctype = base_cand->cand_type; | |
1045 | if (has_single_use (base_in)) | |
1046 | savings = (base_cand->dead_savings | |
1047 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1048 | } | |
1049 | ||
1050 | if (base_cand->next_interp) | |
1051 | base_cand = lookup_cand (base_cand->next_interp); | |
1052 | else | |
1053 | base_cand = NULL; | |
1054 | } | |
1055 | ||
1056 | if (!base) | |
1057 | { | |
1058 | /* No interpretations had anything useful to propagate, so | |
1059 | produce X = (Y + 0) * Z. */ | |
1060 | base = base_in; | |
807e902e | 1061 | index = 0; |
f9453c07 | 1062 | stride = stride_in; |
b2ec94d4 | 1063 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1064 | } |
1065 | ||
1066 | c = alloc_cand_and_find_basis (CAND_MULT, gs, base, index, stride, | |
1067 | ctype, savings); | |
1068 | return c; | |
1069 | } | |
1070 | ||
1071 | /* Create a candidate entry for a statement GS, where GS multiplies | |
1072 | SSA name BASE_IN by constant STRIDE_IN. Propagate any known | |
1073 | information about BASE_IN into the new candidate. Return the new | |
1074 | candidate. */ | |
1075 | ||
1076 | static slsr_cand_t | |
355fe088 | 1077 | create_mul_imm_cand (gimple *gs, tree base_in, tree stride_in, bool speed) |
f9453c07 BS |
1078 | { |
1079 | tree base = NULL_TREE, stride = NULL_TREE, ctype = NULL_TREE; | |
807e902e | 1080 | widest_int index, temp; |
f9453c07 BS |
1081 | unsigned savings = 0; |
1082 | slsr_cand_t c; | |
1083 | slsr_cand_t base_cand = base_cand_from_table (base_in); | |
1084 | ||
1085 | /* Look at all interpretations of the base candidate, if necessary, | |
1086 | to find information to propagate into this candidate. */ | |
9b92d12b | 1087 | while (base_cand && !base && base_cand->kind != CAND_PHI) |
f9453c07 BS |
1088 | { |
1089 | if (base_cand->kind == CAND_MULT | |
1090 | && TREE_CODE (base_cand->stride) == INTEGER_CST) | |
1091 | { | |
1092 | /* Y = (B + i') * S, S constant | |
1093 | X = Y * c | |
1094 | ============================ | |
1095 | X = (B + i') * (S * c) */ | |
807e902e KZ |
1096 | temp = wi::to_widest (base_cand->stride) * wi::to_widest (stride_in); |
1097 | if (wi::fits_to_tree_p (temp, TREE_TYPE (stride_in))) | |
61ba7329 BS |
1098 | { |
1099 | base = base_cand->base_expr; | |
1100 | index = base_cand->index; | |
807e902e | 1101 | stride = wide_int_to_tree (TREE_TYPE (stride_in), temp); |
61ba7329 BS |
1102 | ctype = base_cand->cand_type; |
1103 | if (has_single_use (base_in)) | |
1104 | savings = (base_cand->dead_savings | |
1105 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1106 | } | |
f9453c07 | 1107 | } |
9b92d12b | 1108 | else if (base_cand->kind == CAND_ADD && integer_onep (base_cand->stride)) |
f9453c07 BS |
1109 | { |
1110 | /* Y = B + (i' * 1) | |
1111 | X = Y * c | |
1112 | =========================== | |
1113 | X = (B + i') * c */ | |
3cfd4469 | 1114 | base = base_cand->base_expr; |
f9453c07 BS |
1115 | index = base_cand->index; |
1116 | stride = stride_in; | |
1117 | ctype = base_cand->cand_type; | |
1118 | if (has_single_use (base_in)) | |
1119 | savings = (base_cand->dead_savings | |
1120 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1121 | } | |
1122 | else if (base_cand->kind == CAND_ADD | |
807e902e | 1123 | && base_cand->index == 1 |
f9453c07 BS |
1124 | && TREE_CODE (base_cand->stride) == INTEGER_CST) |
1125 | { | |
1126 | /* Y = B + (1 * S), S constant | |
1127 | X = Y * c | |
1128 | =========================== | |
1129 | X = (B + S) * c */ | |
3cfd4469 | 1130 | base = base_cand->base_expr; |
807e902e | 1131 | index = wi::to_widest (base_cand->stride); |
f9453c07 BS |
1132 | stride = stride_in; |
1133 | ctype = base_cand->cand_type; | |
1134 | if (has_single_use (base_in)) | |
1135 | savings = (base_cand->dead_savings | |
1136 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1137 | } | |
1138 | ||
1139 | if (base_cand->next_interp) | |
1140 | base_cand = lookup_cand (base_cand->next_interp); | |
1141 | else | |
1142 | base_cand = NULL; | |
1143 | } | |
1144 | ||
1145 | if (!base) | |
1146 | { | |
1147 | /* No interpretations had anything useful to propagate, so | |
1148 | produce X = (Y + 0) * c. */ | |
1149 | base = base_in; | |
807e902e | 1150 | index = 0; |
f9453c07 | 1151 | stride = stride_in; |
b2ec94d4 | 1152 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1153 | } |
1154 | ||
1155 | c = alloc_cand_and_find_basis (CAND_MULT, gs, base, index, stride, | |
1156 | ctype, savings); | |
1157 | return c; | |
1158 | } | |
1159 | ||
1160 | /* Given GS which is a multiply of scalar integers, make an appropriate | |
1161 | entry in the candidate table. If this is a multiply of two SSA names, | |
1162 | create two CAND_MULT interpretations and attempt to find a basis for | |
1163 | each of them. Otherwise, create a single CAND_MULT and attempt to | |
1164 | find a basis. */ | |
1165 | ||
1166 | static void | |
355fe088 | 1167 | slsr_process_mul (gimple *gs, tree rhs1, tree rhs2, bool speed) |
f9453c07 BS |
1168 | { |
1169 | slsr_cand_t c, c2; | |
1170 | ||
1171 | /* If this is a multiply of an SSA name with itself, it is highly | |
1172 | unlikely that we will get a strength reduction opportunity, so | |
1173 | don't record it as a candidate. This simplifies the logic for | |
1174 | finding a basis, so if this is removed that must be considered. */ | |
1175 | if (rhs1 == rhs2) | |
1176 | return; | |
1177 | ||
1178 | if (TREE_CODE (rhs2) == SSA_NAME) | |
1179 | { | |
1180 | /* Record an interpretation of this statement in the candidate table | |
3cfd4469 | 1181 | assuming RHS1 is the base expression and RHS2 is the stride. */ |
f9453c07 BS |
1182 | c = create_mul_ssa_cand (gs, rhs1, rhs2, speed); |
1183 | ||
1184 | /* Add the first interpretation to the statement-candidate mapping. */ | |
1185 | add_cand_for_stmt (gs, c); | |
1186 | ||
1187 | /* Record another interpretation of this statement assuming RHS1 | |
3cfd4469 | 1188 | is the stride and RHS2 is the base expression. */ |
f9453c07 BS |
1189 | c2 = create_mul_ssa_cand (gs, rhs2, rhs1, speed); |
1190 | c->next_interp = c2->cand_num; | |
1191 | } | |
1192 | else | |
1193 | { | |
1194 | /* Record an interpretation for the multiply-immediate. */ | |
1195 | c = create_mul_imm_cand (gs, rhs1, rhs2, speed); | |
1196 | ||
1197 | /* Add the interpretation to the statement-candidate mapping. */ | |
1198 | add_cand_for_stmt (gs, c); | |
1199 | } | |
1200 | } | |
1201 | ||
1202 | /* Create a candidate entry for a statement GS, where GS adds two | |
1203 | SSA names BASE_IN and ADDEND_IN if SUBTRACT_P is false, and | |
1204 | subtracts ADDEND_IN from BASE_IN otherwise. Propagate any known | |
1205 | information about the two SSA names into the new candidate. | |
1206 | Return the new candidate. */ | |
1207 | ||
1208 | static slsr_cand_t | |
355fe088 | 1209 | create_add_ssa_cand (gimple *gs, tree base_in, tree addend_in, |
f9453c07 BS |
1210 | bool subtract_p, bool speed) |
1211 | { | |
1212 | tree base = NULL_TREE, stride = NULL_TREE, ctype = NULL; | |
807e902e | 1213 | widest_int index; |
f9453c07 BS |
1214 | unsigned savings = 0; |
1215 | slsr_cand_t c; | |
1216 | slsr_cand_t base_cand = base_cand_from_table (base_in); | |
1217 | slsr_cand_t addend_cand = base_cand_from_table (addend_in); | |
1218 | ||
1219 | /* The most useful transformation is a multiply-immediate feeding | |
1220 | an add or subtract. Look for that first. */ | |
9b92d12b | 1221 | while (addend_cand && !base && addend_cand->kind != CAND_PHI) |
f9453c07 BS |
1222 | { |
1223 | if (addend_cand->kind == CAND_MULT | |
807e902e | 1224 | && addend_cand->index == 0 |
f9453c07 BS |
1225 | && TREE_CODE (addend_cand->stride) == INTEGER_CST) |
1226 | { | |
1227 | /* Z = (B + 0) * S, S constant | |
1228 | X = Y +/- Z | |
1229 | =========================== | |
1230 | X = Y + ((+/-1 * S) * B) */ | |
1231 | base = base_in; | |
807e902e | 1232 | index = wi::to_widest (addend_cand->stride); |
f9453c07 | 1233 | if (subtract_p) |
27bcd47c | 1234 | index = -index; |
3cfd4469 | 1235 | stride = addend_cand->base_expr; |
b2ec94d4 | 1236 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1237 | if (has_single_use (addend_in)) |
1238 | savings = (addend_cand->dead_savings | |
1239 | + stmt_cost (addend_cand->cand_stmt, speed)); | |
1240 | } | |
1241 | ||
1242 | if (addend_cand->next_interp) | |
1243 | addend_cand = lookup_cand (addend_cand->next_interp); | |
1244 | else | |
1245 | addend_cand = NULL; | |
1246 | } | |
1247 | ||
9b92d12b | 1248 | while (base_cand && !base && base_cand->kind != CAND_PHI) |
f9453c07 BS |
1249 | { |
1250 | if (base_cand->kind == CAND_ADD | |
807e902e | 1251 | && (base_cand->index == 0 |
f9453c07 BS |
1252 | || operand_equal_p (base_cand->stride, |
1253 | integer_zero_node, 0))) | |
1254 | { | |
1255 | /* Y = B + (i' * S), i' * S = 0 | |
1256 | X = Y +/- Z | |
1257 | ============================ | |
1258 | X = B + (+/-1 * Z) */ | |
3cfd4469 | 1259 | base = base_cand->base_expr; |
807e902e | 1260 | index = subtract_p ? -1 : 1; |
f9453c07 BS |
1261 | stride = addend_in; |
1262 | ctype = base_cand->cand_type; | |
1263 | if (has_single_use (base_in)) | |
1264 | savings = (base_cand->dead_savings | |
1265 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1266 | } | |
1267 | else if (subtract_p) | |
1268 | { | |
1269 | slsr_cand_t subtrahend_cand = base_cand_from_table (addend_in); | |
1270 | ||
9b92d12b | 1271 | while (subtrahend_cand && !base && subtrahend_cand->kind != CAND_PHI) |
f9453c07 BS |
1272 | { |
1273 | if (subtrahend_cand->kind == CAND_MULT | |
807e902e | 1274 | && subtrahend_cand->index == 0 |
f9453c07 BS |
1275 | && TREE_CODE (subtrahend_cand->stride) == INTEGER_CST) |
1276 | { | |
1277 | /* Z = (B + 0) * S, S constant | |
1278 | X = Y - Z | |
1279 | =========================== | |
1280 | Value: X = Y + ((-1 * S) * B) */ | |
1281 | base = base_in; | |
807e902e | 1282 | index = wi::to_widest (subtrahend_cand->stride); |
27bcd47c | 1283 | index = -index; |
3cfd4469 | 1284 | stride = subtrahend_cand->base_expr; |
b2ec94d4 | 1285 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1286 | if (has_single_use (addend_in)) |
1287 | savings = (subtrahend_cand->dead_savings | |
1288 | + stmt_cost (subtrahend_cand->cand_stmt, speed)); | |
1289 | } | |
1290 | ||
1291 | if (subtrahend_cand->next_interp) | |
1292 | subtrahend_cand = lookup_cand (subtrahend_cand->next_interp); | |
1293 | else | |
1294 | subtrahend_cand = NULL; | |
1295 | } | |
1296 | } | |
1297 | ||
1298 | if (base_cand->next_interp) | |
1299 | base_cand = lookup_cand (base_cand->next_interp); | |
1300 | else | |
1301 | base_cand = NULL; | |
1302 | } | |
1303 | ||
1304 | if (!base) | |
1305 | { | |
1306 | /* No interpretations had anything useful to propagate, so | |
1307 | produce X = Y + (1 * Z). */ | |
1308 | base = base_in; | |
807e902e | 1309 | index = subtract_p ? -1 : 1; |
f9453c07 | 1310 | stride = addend_in; |
b2ec94d4 | 1311 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1312 | } |
1313 | ||
1314 | c = alloc_cand_and_find_basis (CAND_ADD, gs, base, index, stride, | |
1315 | ctype, savings); | |
1316 | return c; | |
1317 | } | |
1318 | ||
1319 | /* Create a candidate entry for a statement GS, where GS adds SSA | |
1320 | name BASE_IN to constant INDEX_IN. Propagate any known information | |
1321 | about BASE_IN into the new candidate. Return the new candidate. */ | |
1322 | ||
1323 | static slsr_cand_t | |
355fe088 | 1324 | create_add_imm_cand (gimple *gs, tree base_in, const widest_int &index_in, |
807e902e | 1325 | bool speed) |
f9453c07 BS |
1326 | { |
1327 | enum cand_kind kind = CAND_ADD; | |
1328 | tree base = NULL_TREE, stride = NULL_TREE, ctype = NULL_TREE; | |
807e902e | 1329 | widest_int index, multiple; |
f9453c07 BS |
1330 | unsigned savings = 0; |
1331 | slsr_cand_t c; | |
1332 | slsr_cand_t base_cand = base_cand_from_table (base_in); | |
1333 | ||
9b92d12b | 1334 | while (base_cand && !base && base_cand->kind != CAND_PHI) |
f9453c07 | 1335 | { |
807e902e | 1336 | signop sign = TYPE_SIGN (TREE_TYPE (base_cand->stride)); |
f9453c07 BS |
1337 | |
1338 | if (TREE_CODE (base_cand->stride) == INTEGER_CST | |
807e902e KZ |
1339 | && wi::multiple_of_p (index_in, wi::to_widest (base_cand->stride), |
1340 | sign, &multiple)) | |
f9453c07 BS |
1341 | { |
1342 | /* Y = (B + i') * S, S constant, c = kS for some integer k | |
1343 | X = Y + c | |
1344 | ============================ | |
1345 | X = (B + (i'+ k)) * S | |
1346 | OR | |
1347 | Y = B + (i' * S), S constant, c = kS for some integer k | |
1348 | X = Y + c | |
1349 | ============================ | |
1350 | X = (B + (i'+ k)) * S */ | |
1351 | kind = base_cand->kind; | |
3cfd4469 | 1352 | base = base_cand->base_expr; |
27bcd47c | 1353 | index = base_cand->index + multiple; |
f9453c07 BS |
1354 | stride = base_cand->stride; |
1355 | ctype = base_cand->cand_type; | |
1356 | if (has_single_use (base_in)) | |
1357 | savings = (base_cand->dead_savings | |
1358 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1359 | } | |
1360 | ||
1361 | if (base_cand->next_interp) | |
1362 | base_cand = lookup_cand (base_cand->next_interp); | |
1363 | else | |
1364 | base_cand = NULL; | |
1365 | } | |
1366 | ||
1367 | if (!base) | |
1368 | { | |
1369 | /* No interpretations had anything useful to propagate, so | |
1370 | produce X = Y + (c * 1). */ | |
1371 | kind = CAND_ADD; | |
1372 | base = base_in; | |
1373 | index = index_in; | |
1374 | stride = integer_one_node; | |
b2ec94d4 | 1375 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1376 | } |
1377 | ||
1378 | c = alloc_cand_and_find_basis (kind, gs, base, index, stride, | |
1379 | ctype, savings); | |
1380 | return c; | |
1381 | } | |
1382 | ||
1383 | /* Given GS which is an add or subtract of scalar integers or pointers, | |
1384 | make at least one appropriate entry in the candidate table. */ | |
1385 | ||
1386 | static void | |
355fe088 | 1387 | slsr_process_add (gimple *gs, tree rhs1, tree rhs2, bool speed) |
f9453c07 BS |
1388 | { |
1389 | bool subtract_p = gimple_assign_rhs_code (gs) == MINUS_EXPR; | |
1390 | slsr_cand_t c = NULL, c2; | |
1391 | ||
1392 | if (TREE_CODE (rhs2) == SSA_NAME) | |
1393 | { | |
3cfd4469 | 1394 | /* First record an interpretation assuming RHS1 is the base expression |
f9453c07 BS |
1395 | and RHS2 is the stride. But it doesn't make sense for the |
1396 | stride to be a pointer, so don't record a candidate in that case. */ | |
b2ec94d4 | 1397 | if (!POINTER_TYPE_P (TREE_TYPE (rhs2))) |
f9453c07 BS |
1398 | { |
1399 | c = create_add_ssa_cand (gs, rhs1, rhs2, subtract_p, speed); | |
1400 | ||
1401 | /* Add the first interpretation to the statement-candidate | |
1402 | mapping. */ | |
1403 | add_cand_for_stmt (gs, c); | |
1404 | } | |
1405 | ||
1406 | /* If the two RHS operands are identical, or this is a subtract, | |
1407 | we're done. */ | |
1408 | if (operand_equal_p (rhs1, rhs2, 0) || subtract_p) | |
1409 | return; | |
1410 | ||
1411 | /* Otherwise, record another interpretation assuming RHS2 is the | |
3cfd4469 | 1412 | base expression and RHS1 is the stride, again provided that the |
f9453c07 | 1413 | stride is not a pointer. */ |
b2ec94d4 | 1414 | if (!POINTER_TYPE_P (TREE_TYPE (rhs1))) |
f9453c07 BS |
1415 | { |
1416 | c2 = create_add_ssa_cand (gs, rhs2, rhs1, false, speed); | |
1417 | if (c) | |
1418 | c->next_interp = c2->cand_num; | |
1419 | else | |
1420 | add_cand_for_stmt (gs, c2); | |
1421 | } | |
1422 | } | |
1423 | else | |
1424 | { | |
f9453c07 | 1425 | /* Record an interpretation for the add-immediate. */ |
807e902e | 1426 | widest_int index = wi::to_widest (rhs2); |
f9453c07 | 1427 | if (subtract_p) |
27bcd47c | 1428 | index = -index; |
f9453c07 BS |
1429 | |
1430 | c = create_add_imm_cand (gs, rhs1, index, speed); | |
1431 | ||
1432 | /* Add the interpretation to the statement-candidate mapping. */ | |
1433 | add_cand_for_stmt (gs, c); | |
1434 | } | |
1435 | } | |
1436 | ||
1437 | /* Given GS which is a negate of a scalar integer, make an appropriate | |
1438 | entry in the candidate table. A negate is equivalent to a multiply | |
1439 | by -1. */ | |
1440 | ||
1441 | static void | |
355fe088 | 1442 | slsr_process_neg (gimple *gs, tree rhs1, bool speed) |
f9453c07 BS |
1443 | { |
1444 | /* Record a CAND_MULT interpretation for the multiply by -1. */ | |
1445 | slsr_cand_t c = create_mul_imm_cand (gs, rhs1, integer_minus_one_node, speed); | |
1446 | ||
1447 | /* Add the interpretation to the statement-candidate mapping. */ | |
1448 | add_cand_for_stmt (gs, c); | |
1449 | } | |
1450 | ||
6b5eea61 BS |
1451 | /* Help function for legal_cast_p, operating on two trees. Checks |
1452 | whether it's allowable to cast from RHS to LHS. See legal_cast_p | |
1453 | for more details. */ | |
1454 | ||
1455 | static bool | |
1456 | legal_cast_p_1 (tree lhs, tree rhs) | |
1457 | { | |
1458 | tree lhs_type, rhs_type; | |
1459 | unsigned lhs_size, rhs_size; | |
1460 | bool lhs_wraps, rhs_wraps; | |
1461 | ||
1462 | lhs_type = TREE_TYPE (lhs); | |
1463 | rhs_type = TREE_TYPE (rhs); | |
1464 | lhs_size = TYPE_PRECISION (lhs_type); | |
1465 | rhs_size = TYPE_PRECISION (rhs_type); | |
20bd649a MP |
1466 | lhs_wraps = ANY_INTEGRAL_TYPE_P (lhs_type) && TYPE_OVERFLOW_WRAPS (lhs_type); |
1467 | rhs_wraps = ANY_INTEGRAL_TYPE_P (rhs_type) && TYPE_OVERFLOW_WRAPS (rhs_type); | |
6b5eea61 BS |
1468 | |
1469 | if (lhs_size < rhs_size | |
1470 | || (rhs_wraps && !lhs_wraps) | |
1471 | || (rhs_wraps && lhs_wraps && rhs_size != lhs_size)) | |
1472 | return false; | |
1473 | ||
1474 | return true; | |
1475 | } | |
1476 | ||
f9453c07 BS |
1477 | /* Return TRUE if GS is a statement that defines an SSA name from |
1478 | a conversion and is legal for us to combine with an add and multiply | |
1479 | in the candidate table. For example, suppose we have: | |
1480 | ||
1481 | A = B + i; | |
1482 | C = (type) A; | |
1483 | D = C * S; | |
1484 | ||
1485 | Without the type-cast, we would create a CAND_MULT for D with base B, | |
1486 | index i, and stride S. We want to record this candidate only if it | |
1487 | is equivalent to apply the type cast following the multiply: | |
1488 | ||
1489 | A = B + i; | |
1490 | E = A * S; | |
1491 | D = (type) E; | |
1492 | ||
1493 | We will record the type with the candidate for D. This allows us | |
1494 | to use a similar previous candidate as a basis. If we have earlier seen | |
1495 | ||
1496 | A' = B + i'; | |
1497 | C' = (type) A'; | |
1498 | D' = C' * S; | |
1499 | ||
1500 | we can replace D with | |
1501 | ||
1502 | D = D' + (i - i') * S; | |
1503 | ||
1504 | But if moving the type-cast would change semantics, we mustn't do this. | |
1505 | ||
1506 | This is legitimate for casts from a non-wrapping integral type to | |
1507 | any integral type of the same or larger size. It is not legitimate | |
1508 | to convert a wrapping type to a non-wrapping type, or to a wrapping | |
1509 | type of a different size. I.e., with a wrapping type, we must | |
1510 | assume that the addition B + i could wrap, in which case performing | |
1511 | the multiply before or after one of the "illegal" type casts will | |
1512 | have different semantics. */ | |
1513 | ||
1514 | static bool | |
355fe088 | 1515 | legal_cast_p (gimple *gs, tree rhs) |
f9453c07 | 1516 | { |
f9453c07 BS |
1517 | if (!is_gimple_assign (gs) |
1518 | || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (gs))) | |
1519 | return false; | |
1520 | ||
6b5eea61 | 1521 | return legal_cast_p_1 (gimple_assign_lhs (gs), rhs); |
f9453c07 BS |
1522 | } |
1523 | ||
1524 | /* Given GS which is a cast to a scalar integer type, determine whether | |
1525 | the cast is legal for strength reduction. If so, make at least one | |
1526 | appropriate entry in the candidate table. */ | |
1527 | ||
1528 | static void | |
355fe088 | 1529 | slsr_process_cast (gimple *gs, tree rhs1, bool speed) |
f9453c07 BS |
1530 | { |
1531 | tree lhs, ctype; | |
1532 | slsr_cand_t base_cand, c, c2; | |
1533 | unsigned savings = 0; | |
1534 | ||
1535 | if (!legal_cast_p (gs, rhs1)) | |
1536 | return; | |
1537 | ||
1538 | lhs = gimple_assign_lhs (gs); | |
1539 | base_cand = base_cand_from_table (rhs1); | |
1540 | ctype = TREE_TYPE (lhs); | |
1541 | ||
9b92d12b | 1542 | if (base_cand && base_cand->kind != CAND_PHI) |
f9453c07 BS |
1543 | { |
1544 | while (base_cand) | |
1545 | { | |
1546 | /* Propagate all data from the base candidate except the type, | |
1547 | which comes from the cast, and the base candidate's cast, | |
1548 | which is no longer applicable. */ | |
1549 | if (has_single_use (rhs1)) | |
1550 | savings = (base_cand->dead_savings | |
1551 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1552 | ||
1553 | c = alloc_cand_and_find_basis (base_cand->kind, gs, | |
3cfd4469 | 1554 | base_cand->base_expr, |
f9453c07 BS |
1555 | base_cand->index, base_cand->stride, |
1556 | ctype, savings); | |
1557 | if (base_cand->next_interp) | |
1558 | base_cand = lookup_cand (base_cand->next_interp); | |
1559 | else | |
1560 | base_cand = NULL; | |
1561 | } | |
1562 | } | |
1563 | else | |
1564 | { | |
1565 | /* If nothing is known about the RHS, create fresh CAND_ADD and | |
1566 | CAND_MULT interpretations: | |
1567 | ||
1568 | X = Y + (0 * 1) | |
1569 | X = (Y + 0) * 1 | |
1570 | ||
1571 | The first of these is somewhat arbitrary, but the choice of | |
1572 | 1 for the stride simplifies the logic for propagating casts | |
1573 | into their uses. */ | |
807e902e KZ |
1574 | c = alloc_cand_and_find_basis (CAND_ADD, gs, rhs1, |
1575 | 0, integer_one_node, ctype, 0); | |
1576 | c2 = alloc_cand_and_find_basis (CAND_MULT, gs, rhs1, | |
1577 | 0, integer_one_node, ctype, 0); | |
f9453c07 BS |
1578 | c->next_interp = c2->cand_num; |
1579 | } | |
1580 | ||
1581 | /* Add the first (or only) interpretation to the statement-candidate | |
1582 | mapping. */ | |
1583 | add_cand_for_stmt (gs, c); | |
1584 | } | |
1585 | ||
1586 | /* Given GS which is a copy of a scalar integer type, make at least one | |
1587 | appropriate entry in the candidate table. | |
1588 | ||
1589 | This interface is included for completeness, but is unnecessary | |
1590 | if this pass immediately follows a pass that performs copy | |
1591 | propagation, such as DOM. */ | |
1592 | ||
1593 | static void | |
355fe088 | 1594 | slsr_process_copy (gimple *gs, tree rhs1, bool speed) |
f9453c07 BS |
1595 | { |
1596 | slsr_cand_t base_cand, c, c2; | |
1597 | unsigned savings = 0; | |
1598 | ||
1599 | base_cand = base_cand_from_table (rhs1); | |
1600 | ||
9b92d12b | 1601 | if (base_cand && base_cand->kind != CAND_PHI) |
f9453c07 BS |
1602 | { |
1603 | while (base_cand) | |
1604 | { | |
1605 | /* Propagate all data from the base candidate. */ | |
1606 | if (has_single_use (rhs1)) | |
1607 | savings = (base_cand->dead_savings | |
1608 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1609 | ||
1610 | c = alloc_cand_and_find_basis (base_cand->kind, gs, | |
3cfd4469 | 1611 | base_cand->base_expr, |
f9453c07 BS |
1612 | base_cand->index, base_cand->stride, |
1613 | base_cand->cand_type, savings); | |
1614 | if (base_cand->next_interp) | |
1615 | base_cand = lookup_cand (base_cand->next_interp); | |
1616 | else | |
1617 | base_cand = NULL; | |
1618 | } | |
1619 | } | |
1620 | else | |
1621 | { | |
1622 | /* If nothing is known about the RHS, create fresh CAND_ADD and | |
1623 | CAND_MULT interpretations: | |
1624 | ||
1625 | X = Y + (0 * 1) | |
1626 | X = (Y + 0) * 1 | |
1627 | ||
1628 | The first of these is somewhat arbitrary, but the choice of | |
1629 | 1 for the stride simplifies the logic for propagating casts | |
1630 | into their uses. */ | |
807e902e KZ |
1631 | c = alloc_cand_and_find_basis (CAND_ADD, gs, rhs1, |
1632 | 0, integer_one_node, TREE_TYPE (rhs1), 0); | |
1633 | c2 = alloc_cand_and_find_basis (CAND_MULT, gs, rhs1, | |
1634 | 0, integer_one_node, TREE_TYPE (rhs1), 0); | |
f9453c07 BS |
1635 | c->next_interp = c2->cand_num; |
1636 | } | |
1637 | ||
1638 | /* Add the first (or only) interpretation to the statement-candidate | |
1639 | mapping. */ | |
1640 | add_cand_for_stmt (gs, c); | |
1641 | } | |
1642 | \f | |
4d9192b5 TS |
1643 | class find_candidates_dom_walker : public dom_walker |
1644 | { | |
1645 | public: | |
1646 | find_candidates_dom_walker (cdi_direction direction) | |
1647 | : dom_walker (direction) {} | |
3daacdcd | 1648 | virtual edge before_dom_children (basic_block); |
4d9192b5 TS |
1649 | }; |
1650 | ||
f9453c07 BS |
1651 | /* Find strength-reduction candidates in block BB. */ |
1652 | ||
3daacdcd | 1653 | edge |
4d9192b5 | 1654 | find_candidates_dom_walker::before_dom_children (basic_block bb) |
f9453c07 BS |
1655 | { |
1656 | bool speed = optimize_bb_for_speed_p (bb); | |
f9453c07 | 1657 | |
538dd0b7 DM |
1658 | for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi); |
1659 | gsi_next (&gsi)) | |
1660 | slsr_process_phi (gsi.phi (), speed); | |
9b92d12b | 1661 | |
538dd0b7 DM |
1662 | for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi); |
1663 | gsi_next (&gsi)) | |
f9453c07 | 1664 | { |
355fe088 | 1665 | gimple *gs = gsi_stmt (gsi); |
f9453c07 | 1666 | |
2749c8f6 BS |
1667 | if (gimple_vuse (gs) && gimple_assign_single_p (gs)) |
1668 | slsr_process_ref (gs); | |
1669 | ||
1670 | else if (is_gimple_assign (gs) | |
1671 | && SCALAR_INT_MODE_P | |
1672 | (TYPE_MODE (TREE_TYPE (gimple_assign_lhs (gs))))) | |
f9453c07 BS |
1673 | { |
1674 | tree rhs1 = NULL_TREE, rhs2 = NULL_TREE; | |
1675 | ||
1676 | switch (gimple_assign_rhs_code (gs)) | |
1677 | { | |
1678 | case MULT_EXPR: | |
1679 | case PLUS_EXPR: | |
1680 | rhs1 = gimple_assign_rhs1 (gs); | |
1681 | rhs2 = gimple_assign_rhs2 (gs); | |
1682 | /* Should never happen, but currently some buggy situations | |
1683 | in earlier phases put constants in rhs1. */ | |
1684 | if (TREE_CODE (rhs1) != SSA_NAME) | |
1685 | continue; | |
1686 | break; | |
1687 | ||
1688 | /* Possible future opportunity: rhs1 of a ptr+ can be | |
1689 | an ADDR_EXPR. */ | |
1690 | case POINTER_PLUS_EXPR: | |
1691 | case MINUS_EXPR: | |
1692 | rhs2 = gimple_assign_rhs2 (gs); | |
81fea426 | 1693 | gcc_fallthrough (); |
f9453c07 | 1694 | |
d822570f | 1695 | CASE_CONVERT: |
f9453c07 BS |
1696 | case MODIFY_EXPR: |
1697 | case NEGATE_EXPR: | |
1698 | rhs1 = gimple_assign_rhs1 (gs); | |
1699 | if (TREE_CODE (rhs1) != SSA_NAME) | |
1700 | continue; | |
1701 | break; | |
1702 | ||
1703 | default: | |
1704 | ; | |
1705 | } | |
1706 | ||
1707 | switch (gimple_assign_rhs_code (gs)) | |
1708 | { | |
1709 | case MULT_EXPR: | |
1710 | slsr_process_mul (gs, rhs1, rhs2, speed); | |
1711 | break; | |
1712 | ||
1713 | case PLUS_EXPR: | |
1714 | case POINTER_PLUS_EXPR: | |
1715 | case MINUS_EXPR: | |
1716 | slsr_process_add (gs, rhs1, rhs2, speed); | |
1717 | break; | |
1718 | ||
1719 | case NEGATE_EXPR: | |
1720 | slsr_process_neg (gs, rhs1, speed); | |
1721 | break; | |
1722 | ||
d822570f | 1723 | CASE_CONVERT: |
f9453c07 BS |
1724 | slsr_process_cast (gs, rhs1, speed); |
1725 | break; | |
1726 | ||
1727 | case MODIFY_EXPR: | |
1728 | slsr_process_copy (gs, rhs1, speed); | |
1729 | break; | |
1730 | ||
1731 | default: | |
1732 | ; | |
1733 | } | |
1734 | } | |
1735 | } | |
3daacdcd | 1736 | return NULL; |
f9453c07 BS |
1737 | } |
1738 | \f | |
1739 | /* Dump a candidate for debug. */ | |
1740 | ||
1741 | static void | |
1742 | dump_candidate (slsr_cand_t c) | |
1743 | { | |
1744 | fprintf (dump_file, "%3d [%d] ", c->cand_num, | |
1745 | gimple_bb (c->cand_stmt)->index); | |
1746 | print_gimple_stmt (dump_file, c->cand_stmt, 0, 0); | |
1747 | switch (c->kind) | |
1748 | { | |
1749 | case CAND_MULT: | |
1750 | fputs (" MULT : (", dump_file); | |
3cfd4469 | 1751 | print_generic_expr (dump_file, c->base_expr, 0); |
f9453c07 | 1752 | fputs (" + ", dump_file); |
807e902e | 1753 | print_decs (c->index, dump_file); |
f9453c07 BS |
1754 | fputs (") * ", dump_file); |
1755 | print_generic_expr (dump_file, c->stride, 0); | |
1756 | fputs (" : ", dump_file); | |
1757 | break; | |
1758 | case CAND_ADD: | |
1759 | fputs (" ADD : ", dump_file); | |
3cfd4469 | 1760 | print_generic_expr (dump_file, c->base_expr, 0); |
f9453c07 | 1761 | fputs (" + (", dump_file); |
807e902e | 1762 | print_decs (c->index, dump_file); |
f9453c07 BS |
1763 | fputs (" * ", dump_file); |
1764 | print_generic_expr (dump_file, c->stride, 0); | |
1765 | fputs (") : ", dump_file); | |
1766 | break; | |
2749c8f6 BS |
1767 | case CAND_REF: |
1768 | fputs (" REF : ", dump_file); | |
3cfd4469 | 1769 | print_generic_expr (dump_file, c->base_expr, 0); |
2749c8f6 BS |
1770 | fputs (" + (", dump_file); |
1771 | print_generic_expr (dump_file, c->stride, 0); | |
1772 | fputs (") + ", dump_file); | |
807e902e | 1773 | print_decs (c->index, dump_file); |
2749c8f6 BS |
1774 | fputs (" : ", dump_file); |
1775 | break; | |
9b92d12b BS |
1776 | case CAND_PHI: |
1777 | fputs (" PHI : ", dump_file); | |
1778 | print_generic_expr (dump_file, c->base_expr, 0); | |
1779 | fputs (" + (unknown * ", dump_file); | |
1780 | print_generic_expr (dump_file, c->stride, 0); | |
1781 | fputs (") : ", dump_file); | |
1782 | break; | |
f9453c07 BS |
1783 | default: |
1784 | gcc_unreachable (); | |
1785 | } | |
1786 | print_generic_expr (dump_file, c->cand_type, 0); | |
1787 | fprintf (dump_file, "\n basis: %d dependent: %d sibling: %d\n", | |
1788 | c->basis, c->dependent, c->sibling); | |
1789 | fprintf (dump_file, " next-interp: %d dead-savings: %d\n", | |
1790 | c->next_interp, c->dead_savings); | |
1791 | if (c->def_phi) | |
9b92d12b | 1792 | fprintf (dump_file, " phi: %d\n", c->def_phi); |
f9453c07 BS |
1793 | fputs ("\n", dump_file); |
1794 | } | |
1795 | ||
1796 | /* Dump the candidate vector for debug. */ | |
1797 | ||
1798 | static void | |
1799 | dump_cand_vec (void) | |
1800 | { | |
1801 | unsigned i; | |
1802 | slsr_cand_t c; | |
1803 | ||
1804 | fprintf (dump_file, "\nStrength reduction candidate vector:\n\n"); | |
1805 | ||
9771b263 | 1806 | FOR_EACH_VEC_ELT (cand_vec, i, c) |
f9453c07 BS |
1807 | dump_candidate (c); |
1808 | } | |
1809 | ||
2749c8f6 | 1810 | /* Callback used to dump the candidate chains hash table. */ |
f9453c07 | 1811 | |
4a8fb1a1 LC |
1812 | int |
1813 | ssa_base_cand_dump_callback (cand_chain **slot, void *ignored ATTRIBUTE_UNUSED) | |
f9453c07 | 1814 | { |
4a8fb1a1 | 1815 | const_cand_chain_t chain = *slot; |
2749c8f6 | 1816 | cand_chain_t p; |
f9453c07 | 1817 | |
3cfd4469 | 1818 | print_generic_expr (dump_file, chain->base_expr, 0); |
2749c8f6 | 1819 | fprintf (dump_file, " -> %d", chain->cand->cand_num); |
f9453c07 | 1820 | |
2749c8f6 BS |
1821 | for (p = chain->next; p; p = p->next) |
1822 | fprintf (dump_file, " -> %d", p->cand->cand_num); | |
f9453c07 | 1823 | |
2749c8f6 BS |
1824 | fputs ("\n", dump_file); |
1825 | return 1; | |
1826 | } | |
f9453c07 | 1827 | |
2749c8f6 | 1828 | /* Dump the candidate chains. */ |
f9453c07 | 1829 | |
2749c8f6 BS |
1830 | static void |
1831 | dump_cand_chains (void) | |
1832 | { | |
1833 | fprintf (dump_file, "\nStrength reduction candidate chains:\n\n"); | |
c203e8a7 TS |
1834 | base_cand_map->traverse_noresize <void *, ssa_base_cand_dump_callback> |
1835 | (NULL); | |
f9453c07 BS |
1836 | fputs ("\n", dump_file); |
1837 | } | |
88ca9ea1 BS |
1838 | |
1839 | /* Dump the increment vector for debug. */ | |
1840 | ||
1841 | static void | |
1842 | dump_incr_vec (void) | |
1843 | { | |
1844 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1845 | { | |
1846 | unsigned i; | |
1847 | ||
1848 | fprintf (dump_file, "\nIncrement vector:\n\n"); | |
1849 | ||
1850 | for (i = 0; i < incr_vec_len; i++) | |
1851 | { | |
1852 | fprintf (dump_file, "%3d increment: ", i); | |
807e902e | 1853 | print_decs (incr_vec[i].incr, dump_file); |
88ca9ea1 BS |
1854 | fprintf (dump_file, "\n count: %d", incr_vec[i].count); |
1855 | fprintf (dump_file, "\n cost: %d", incr_vec[i].cost); | |
1856 | fputs ("\n initializer: ", dump_file); | |
1857 | print_generic_expr (dump_file, incr_vec[i].initializer, 0); | |
1858 | fputs ("\n\n", dump_file); | |
1859 | } | |
1860 | } | |
1861 | } | |
f9453c07 | 1862 | \f |
2749c8f6 BS |
1863 | /* Replace *EXPR in candidate C with an equivalent strength-reduced |
1864 | data reference. */ | |
1865 | ||
1866 | static void | |
1867 | replace_ref (tree *expr, slsr_cand_t c) | |
1868 | { | |
78f6dd68 MJ |
1869 | tree add_expr, mem_ref, acc_type = TREE_TYPE (*expr); |
1870 | unsigned HOST_WIDE_INT misalign; | |
1871 | unsigned align; | |
1872 | ||
1873 | /* Ensure the memory reference carries the minimum alignment | |
1874 | requirement for the data type. See PR58041. */ | |
1875 | get_object_alignment_1 (*expr, &align, &misalign); | |
1876 | if (misalign != 0) | |
146ec50f | 1877 | align = least_bit_hwi (misalign); |
78f6dd68 MJ |
1878 | if (align < TYPE_ALIGN (acc_type)) |
1879 | acc_type = build_aligned_type (acc_type, align); | |
1880 | ||
1881 | add_expr = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (c->base_expr), | |
1882 | c->base_expr, c->stride); | |
1883 | mem_ref = fold_build2 (MEM_REF, acc_type, add_expr, | |
807e902e | 1884 | wide_int_to_tree (c->cand_type, c->index)); |
78f6dd68 | 1885 | |
2749c8f6 BS |
1886 | /* Gimplify the base addressing expression for the new MEM_REF tree. */ |
1887 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
1888 | TREE_OPERAND (mem_ref, 0) | |
1889 | = force_gimple_operand_gsi (&gsi, TREE_OPERAND (mem_ref, 0), | |
1890 | /*simple_p=*/true, NULL, | |
1891 | /*before=*/true, GSI_SAME_STMT); | |
1892 | copy_ref_info (mem_ref, *expr); | |
1893 | *expr = mem_ref; | |
1894 | update_stmt (c->cand_stmt); | |
1895 | } | |
1896 | ||
1897 | /* Replace CAND_REF candidate C, each sibling of candidate C, and each | |
1898 | dependent of candidate C with an equivalent strength-reduced data | |
1899 | reference. */ | |
1900 | ||
1901 | static void | |
1902 | replace_refs (slsr_cand_t c) | |
1903 | { | |
96d75a2c YZ |
1904 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1905 | { | |
1906 | fputs ("Replacing reference: ", dump_file); | |
1907 | print_gimple_stmt (dump_file, c->cand_stmt, 0, 0); | |
1908 | } | |
1909 | ||
2749c8f6 BS |
1910 | if (gimple_vdef (c->cand_stmt)) |
1911 | { | |
1912 | tree *lhs = gimple_assign_lhs_ptr (c->cand_stmt); | |
1913 | replace_ref (lhs, c); | |
1914 | } | |
1915 | else | |
1916 | { | |
1917 | tree *rhs = gimple_assign_rhs1_ptr (c->cand_stmt); | |
1918 | replace_ref (rhs, c); | |
1919 | } | |
1920 | ||
96d75a2c YZ |
1921 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1922 | { | |
1923 | fputs ("With: ", dump_file); | |
1924 | print_gimple_stmt (dump_file, c->cand_stmt, 0, 0); | |
1925 | fputs ("\n", dump_file); | |
1926 | } | |
1927 | ||
2749c8f6 BS |
1928 | if (c->sibling) |
1929 | replace_refs (lookup_cand (c->sibling)); | |
1930 | ||
1931 | if (c->dependent) | |
1932 | replace_refs (lookup_cand (c->dependent)); | |
1933 | } | |
1934 | ||
9b92d12b BS |
1935 | /* Return TRUE if candidate C is dependent upon a PHI. */ |
1936 | ||
1937 | static bool | |
1938 | phi_dependent_cand_p (slsr_cand_t c) | |
1939 | { | |
1940 | /* A candidate is not necessarily dependent upon a PHI just because | |
1941 | it has a phi definition for its base name. It may have a basis | |
1942 | that relies upon the same phi definition, in which case the PHI | |
1943 | is irrelevant to this candidate. */ | |
1944 | return (c->def_phi | |
1945 | && c->basis | |
1946 | && lookup_cand (c->basis)->def_phi != c->def_phi); | |
1947 | } | |
1948 | ||
f9453c07 BS |
1949 | /* Calculate the increment required for candidate C relative to |
1950 | its basis. */ | |
1951 | ||
807e902e | 1952 | static widest_int |
f9453c07 BS |
1953 | cand_increment (slsr_cand_t c) |
1954 | { | |
1955 | slsr_cand_t basis; | |
1956 | ||
1957 | /* If the candidate doesn't have a basis, just return its own | |
1958 | index. This is useful in record_increments to help us find | |
9b92d12b BS |
1959 | an existing initializer. Also, if the candidate's basis is |
1960 | hidden by a phi, then its own index will be the increment | |
1961 | from the newly introduced phi basis. */ | |
1962 | if (!c->basis || phi_dependent_cand_p (c)) | |
f9453c07 BS |
1963 | return c->index; |
1964 | ||
1965 | basis = lookup_cand (c->basis); | |
3cfd4469 | 1966 | gcc_assert (operand_equal_p (c->base_expr, basis->base_expr, 0)); |
27bcd47c | 1967 | return c->index - basis->index; |
f9453c07 BS |
1968 | } |
1969 | ||
88ca9ea1 BS |
1970 | /* Calculate the increment required for candidate C relative to |
1971 | its basis. If we aren't going to generate pointer arithmetic | |
1972 | for this candidate, return the absolute value of that increment | |
1973 | instead. */ | |
1974 | ||
807e902e | 1975 | static inline widest_int |
88ca9ea1 BS |
1976 | cand_abs_increment (slsr_cand_t c) |
1977 | { | |
807e902e | 1978 | widest_int increment = cand_increment (c); |
88ca9ea1 | 1979 | |
807e902e | 1980 | if (!address_arithmetic_p && wi::neg_p (increment)) |
27bcd47c | 1981 | increment = -increment; |
88ca9ea1 BS |
1982 | |
1983 | return increment; | |
1984 | } | |
1985 | ||
f9453c07 BS |
1986 | /* Return TRUE iff candidate C has already been replaced under |
1987 | another interpretation. */ | |
1988 | ||
1989 | static inline bool | |
1990 | cand_already_replaced (slsr_cand_t c) | |
1991 | { | |
1992 | return (gimple_bb (c->cand_stmt) == 0); | |
1993 | } | |
1994 | ||
9b92d12b BS |
1995 | /* Common logic used by replace_unconditional_candidate and |
1996 | replace_conditional_candidate. */ | |
f9453c07 BS |
1997 | |
1998 | static void | |
807e902e | 1999 | replace_mult_candidate (slsr_cand_t c, tree basis_name, widest_int bump) |
f9453c07 | 2000 | { |
9b92d12b BS |
2001 | tree target_type = TREE_TYPE (gimple_assign_lhs (c->cand_stmt)); |
2002 | enum tree_code cand_code = gimple_assign_rhs_code (c->cand_stmt); | |
2003 | ||
f9453c07 BS |
2004 | /* It is highly unlikely, but possible, that the resulting |
2005 | bump doesn't fit in a HWI. Abandon the replacement | |
9b92d12b BS |
2006 | in this case. This does not affect siblings or dependents |
2007 | of C. Restriction to signed HWI is conservative for unsigned | |
2008 | types but allows for safe negation without twisted logic. */ | |
807e902e | 2009 | if (wi::fits_shwi_p (bump) |
9b92d12b BS |
2010 | && bump.to_shwi () != HOST_WIDE_INT_MIN |
2011 | /* It is not useful to replace casts, copies, or adds of | |
2012 | an SSA name and a constant. */ | |
2013 | && cand_code != MODIFY_EXPR | |
d822570f | 2014 | && !CONVERT_EXPR_CODE_P (cand_code) |
9b92d12b BS |
2015 | && cand_code != PLUS_EXPR |
2016 | && cand_code != POINTER_PLUS_EXPR | |
2017 | && cand_code != MINUS_EXPR) | |
2018 | { | |
2019 | enum tree_code code = PLUS_EXPR; | |
2020 | tree bump_tree; | |
355fe088 | 2021 | gimple *stmt_to_print = NULL; |
9b92d12b BS |
2022 | |
2023 | /* If the basis name and the candidate's LHS have incompatible | |
2024 | types, introduce a cast. */ | |
2025 | if (!useless_type_conversion_p (target_type, TREE_TYPE (basis_name))) | |
a7a7d10e | 2026 | basis_name = introduce_cast_before_cand (c, target_type, basis_name); |
807e902e | 2027 | if (wi::neg_p (bump)) |
9b92d12b BS |
2028 | { |
2029 | code = MINUS_EXPR; | |
2030 | bump = -bump; | |
2031 | } | |
2032 | ||
807e902e | 2033 | bump_tree = wide_int_to_tree (target_type, bump); |
9b92d12b BS |
2034 | |
2035 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2036 | { | |
2037 | fputs ("Replacing: ", dump_file); | |
2038 | print_gimple_stmt (dump_file, c->cand_stmt, 0, 0); | |
2039 | } | |
2040 | ||
807e902e | 2041 | if (bump == 0) |
9b92d12b BS |
2042 | { |
2043 | tree lhs = gimple_assign_lhs (c->cand_stmt); | |
538dd0b7 | 2044 | gassign *copy_stmt = gimple_build_assign (lhs, basis_name); |
9b92d12b BS |
2045 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); |
2046 | gimple_set_location (copy_stmt, gimple_location (c->cand_stmt)); | |
2047 | gsi_replace (&gsi, copy_stmt, false); | |
0100cd3f | 2048 | c->cand_stmt = copy_stmt; |
9b92d12b BS |
2049 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2050 | stmt_to_print = copy_stmt; | |
2051 | } | |
2052 | else | |
2053 | { | |
2054 | tree rhs1, rhs2; | |
2055 | if (cand_code != NEGATE_EXPR) { | |
2056 | rhs1 = gimple_assign_rhs1 (c->cand_stmt); | |
2057 | rhs2 = gimple_assign_rhs2 (c->cand_stmt); | |
2058 | } | |
2059 | if (cand_code != NEGATE_EXPR | |
2060 | && ((operand_equal_p (rhs1, basis_name, 0) | |
2061 | && operand_equal_p (rhs2, bump_tree, 0)) | |
2062 | || (operand_equal_p (rhs1, bump_tree, 0) | |
2063 | && operand_equal_p (rhs2, basis_name, 0)))) | |
2064 | { | |
2065 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2066 | { | |
2067 | fputs ("(duplicate, not actually replacing)", dump_file); | |
2068 | stmt_to_print = c->cand_stmt; | |
2069 | } | |
2070 | } | |
2071 | else | |
2072 | { | |
2073 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
2074 | gimple_assign_set_rhs_with_ops (&gsi, code, | |
2075 | basis_name, bump_tree); | |
2076 | update_stmt (gsi_stmt (gsi)); | |
bb0d2039 | 2077 | c->cand_stmt = gsi_stmt (gsi); |
9b92d12b BS |
2078 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2079 | stmt_to_print = gsi_stmt (gsi); | |
2080 | } | |
2081 | } | |
2082 | ||
2083 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2084 | { | |
2085 | fputs ("With: ", dump_file); | |
2086 | print_gimple_stmt (dump_file, stmt_to_print, 0, 0); | |
2087 | fputs ("\n", dump_file); | |
2088 | } | |
2089 | } | |
2090 | } | |
2091 | ||
2092 | /* Replace candidate C with an add or subtract. Note that we only | |
2093 | operate on CAND_MULTs with known strides, so we will never generate | |
2094 | a POINTER_PLUS_EXPR. Each candidate X = (B + i) * S is replaced by | |
2095 | X = Y + ((i - i') * S), as described in the module commentary. The | |
2096 | folded value ((i - i') * S) is referred to here as the "bump." */ | |
2097 | ||
2098 | static void | |
2099 | replace_unconditional_candidate (slsr_cand_t c) | |
2100 | { | |
2101 | slsr_cand_t basis; | |
9b92d12b BS |
2102 | |
2103 | if (cand_already_replaced (c)) | |
f9453c07 BS |
2104 | return; |
2105 | ||
2106 | basis = lookup_cand (c->basis); | |
807e902e | 2107 | widest_int bump = cand_increment (c) * wi::to_widest (c->stride); |
9b92d12b | 2108 | |
a7a7d10e | 2109 | replace_mult_candidate (c, gimple_assign_lhs (basis->cand_stmt), bump); |
9b92d12b BS |
2110 | } |
2111 | \f | |
7bf55a70 BS |
2112 | /* Return the index in the increment vector of the given INCREMENT, |
2113 | or -1 if not found. The latter can occur if more than | |
2114 | MAX_INCR_VEC_LEN increments have been found. */ | |
9b92d12b | 2115 | |
7bf55a70 | 2116 | static inline int |
807e902e | 2117 | incr_vec_index (const widest_int &increment) |
9b92d12b BS |
2118 | { |
2119 | unsigned i; | |
2120 | ||
2121 | for (i = 0; i < incr_vec_len && increment != incr_vec[i].incr; i++) | |
2122 | ; | |
2123 | ||
7bf55a70 BS |
2124 | if (i < incr_vec_len) |
2125 | return i; | |
2126 | else | |
2127 | return -1; | |
9b92d12b BS |
2128 | } |
2129 | ||
2130 | /* Create a new statement along edge E to add BASIS_NAME to the product | |
2131 | of INCREMENT and the stride of candidate C. Create and return a new | |
2132 | SSA name from *VAR to be used as the LHS of the new statement. | |
2133 | KNOWN_STRIDE is true iff C's stride is a constant. */ | |
2134 | ||
2135 | static tree | |
2136 | create_add_on_incoming_edge (slsr_cand_t c, tree basis_name, | |
807e902e | 2137 | widest_int increment, edge e, location_t loc, |
9b92d12b BS |
2138 | bool known_stride) |
2139 | { | |
2140 | basic_block insert_bb; | |
2141 | gimple_stmt_iterator gsi; | |
2142 | tree lhs, basis_type; | |
538dd0b7 | 2143 | gassign *new_stmt; |
9b92d12b BS |
2144 | |
2145 | /* If the add candidate along this incoming edge has the same | |
2146 | index as C's hidden basis, the hidden basis represents this | |
2147 | edge correctly. */ | |
807e902e | 2148 | if (increment == 0) |
9b92d12b BS |
2149 | return basis_name; |
2150 | ||
2151 | basis_type = TREE_TYPE (basis_name); | |
2152 | lhs = make_temp_ssa_name (basis_type, NULL, "slsr"); | |
2153 | ||
2154 | if (known_stride) | |
7139194b | 2155 | { |
9b92d12b BS |
2156 | tree bump_tree; |
2157 | enum tree_code code = PLUS_EXPR; | |
807e902e KZ |
2158 | widest_int bump = increment * wi::to_widest (c->stride); |
2159 | if (wi::neg_p (bump)) | |
9b92d12b BS |
2160 | { |
2161 | code = MINUS_EXPR; | |
2162 | bump = -bump; | |
2163 | } | |
2164 | ||
807e902e | 2165 | bump_tree = wide_int_to_tree (basis_type, bump); |
0d0e4a03 | 2166 | new_stmt = gimple_build_assign (lhs, code, basis_name, bump_tree); |
7139194b AH |
2167 | } |
2168 | else | |
2169 | { | |
7bf55a70 | 2170 | int i; |
807e902e | 2171 | bool negate_incr = (!address_arithmetic_p && wi::neg_p (increment)); |
9b92d12b | 2172 | i = incr_vec_index (negate_incr ? -increment : increment); |
7bf55a70 | 2173 | gcc_assert (i >= 0); |
f9453c07 | 2174 | |
9b92d12b BS |
2175 | if (incr_vec[i].initializer) |
2176 | { | |
2177 | enum tree_code code = negate_incr ? MINUS_EXPR : PLUS_EXPR; | |
0d0e4a03 JJ |
2178 | new_stmt = gimple_build_assign (lhs, code, basis_name, |
2179 | incr_vec[i].initializer); | |
9b92d12b | 2180 | } |
807e902e | 2181 | else if (increment == 1) |
0d0e4a03 | 2182 | new_stmt = gimple_build_assign (lhs, PLUS_EXPR, basis_name, c->stride); |
807e902e | 2183 | else if (increment == -1) |
0d0e4a03 JJ |
2184 | new_stmt = gimple_build_assign (lhs, MINUS_EXPR, basis_name, |
2185 | c->stride); | |
9b92d12b BS |
2186 | else |
2187 | gcc_unreachable (); | |
f9453c07 BS |
2188 | } |
2189 | ||
9b92d12b BS |
2190 | insert_bb = single_succ_p (e->src) ? e->src : split_edge (e); |
2191 | gsi = gsi_last_bb (insert_bb); | |
2192 | ||
2193 | if (!gsi_end_p (gsi) && is_ctrl_stmt (gsi_stmt (gsi))) | |
2194 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); | |
2195 | else | |
2196 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); | |
2197 | ||
2198 | gimple_set_location (new_stmt, loc); | |
f9453c07 BS |
2199 | |
2200 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2201 | { | |
9b92d12b BS |
2202 | fprintf (dump_file, "Inserting in block %d: ", insert_bb->index); |
2203 | print_gimple_stmt (dump_file, new_stmt, 0, 0); | |
f9453c07 BS |
2204 | } |
2205 | ||
9b92d12b BS |
2206 | return lhs; |
2207 | } | |
2208 | ||
2209 | /* Given a candidate C with BASIS_NAME being the LHS of C's basis which | |
2210 | is hidden by the phi node FROM_PHI, create a new phi node in the same | |
2211 | block as FROM_PHI. The new phi is suitable for use as a basis by C, | |
2212 | with its phi arguments representing conditional adjustments to the | |
2213 | hidden basis along conditional incoming paths. Those adjustments are | |
2214 | made by creating add statements (and sometimes recursively creating | |
2215 | phis) along those incoming paths. LOC is the location to attach to | |
2216 | the introduced statements. KNOWN_STRIDE is true iff C's stride is a | |
2217 | constant. */ | |
2218 | ||
2219 | static tree | |
355fe088 | 2220 | create_phi_basis (slsr_cand_t c, gimple *from_phi, tree basis_name, |
9b92d12b BS |
2221 | location_t loc, bool known_stride) |
2222 | { | |
2223 | int i; | |
2224 | tree name, phi_arg; | |
538dd0b7 | 2225 | gphi *phi; |
9b92d12b BS |
2226 | slsr_cand_t basis = lookup_cand (c->basis); |
2227 | int nargs = gimple_phi_num_args (from_phi); | |
2228 | basic_block phi_bb = gimple_bb (from_phi); | |
5b3d5f76 | 2229 | slsr_cand_t phi_cand = *stmt_cand_map->get (from_phi); |
c8189787 | 2230 | auto_vec<tree> phi_args (nargs); |
9b92d12b BS |
2231 | |
2232 | /* Process each argument of the existing phi that represents | |
2233 | conditionally-executed add candidates. */ | |
2234 | for (i = 0; i < nargs; i++) | |
f9453c07 | 2235 | { |
9b92d12b BS |
2236 | edge e = (*phi_bb->preds)[i]; |
2237 | tree arg = gimple_phi_arg_def (from_phi, i); | |
2238 | tree feeding_def; | |
2239 | ||
2240 | /* If the phi argument is the base name of the CAND_PHI, then | |
2241 | this incoming arc should use the hidden basis. */ | |
2242 | if (operand_equal_p (arg, phi_cand->base_expr, 0)) | |
807e902e | 2243 | if (basis->index == 0) |
9b92d12b BS |
2244 | feeding_def = gimple_assign_lhs (basis->cand_stmt); |
2245 | else | |
2246 | { | |
807e902e | 2247 | widest_int incr = -basis->index; |
9b92d12b BS |
2248 | feeding_def = create_add_on_incoming_edge (c, basis_name, incr, |
2249 | e, loc, known_stride); | |
2250 | } | |
2251 | else | |
f9453c07 | 2252 | { |
355fe088 | 2253 | gimple *arg_def = SSA_NAME_DEF_STMT (arg); |
9b92d12b BS |
2254 | |
2255 | /* If there is another phi along this incoming edge, we must | |
2256 | process it in the same fashion to ensure that all basis | |
2257 | adjustments are made along its incoming edges. */ | |
2258 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
2259 | feeding_def = create_phi_basis (c, arg_def, basis_name, | |
2260 | loc, known_stride); | |
2261 | else | |
f9453c07 | 2262 | { |
9b92d12b | 2263 | slsr_cand_t arg_cand = base_cand_from_table (arg); |
807e902e | 2264 | widest_int diff = arg_cand->index - basis->index; |
9b92d12b BS |
2265 | feeding_def = create_add_on_incoming_edge (c, basis_name, diff, |
2266 | e, loc, known_stride); | |
f9453c07 BS |
2267 | } |
2268 | } | |
9b92d12b BS |
2269 | |
2270 | /* Because of recursion, we need to save the arguments in a vector | |
2271 | so we can create the PHI statement all at once. Otherwise the | |
2272 | storage for the half-created PHI can be reclaimed. */ | |
2273 | phi_args.safe_push (feeding_def); | |
f9453c07 | 2274 | } |
9b92d12b BS |
2275 | |
2276 | /* Create the new phi basis. */ | |
2277 | name = make_temp_ssa_name (TREE_TYPE (basis_name), NULL, "slsr"); | |
2278 | phi = create_phi_node (name, phi_bb); | |
2279 | SSA_NAME_DEF_STMT (name) = phi; | |
2280 | ||
2281 | FOR_EACH_VEC_ELT (phi_args, i, phi_arg) | |
2282 | { | |
2283 | edge e = (*phi_bb->preds)[i]; | |
2284 | add_phi_arg (phi, phi_arg, e, loc); | |
2285 | } | |
2286 | ||
2287 | update_stmt (phi); | |
2288 | ||
f9453c07 BS |
2289 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2290 | { | |
9b92d12b BS |
2291 | fputs ("Introducing new phi basis: ", dump_file); |
2292 | print_gimple_stmt (dump_file, phi, 0, 0); | |
f9453c07 | 2293 | } |
9b92d12b BS |
2294 | |
2295 | return name; | |
f9453c07 BS |
2296 | } |
2297 | ||
9b92d12b BS |
2298 | /* Given a candidate C whose basis is hidden by at least one intervening |
2299 | phi, introduce a matching number of new phis to represent its basis | |
2300 | adjusted by conditional increments along possible incoming paths. Then | |
2301 | replace C as though it were an unconditional candidate, using the new | |
2302 | basis. */ | |
f9453c07 BS |
2303 | |
2304 | static void | |
9b92d12b | 2305 | replace_conditional_candidate (slsr_cand_t c) |
f9453c07 | 2306 | { |
a7a7d10e | 2307 | tree basis_name, name; |
9b92d12b BS |
2308 | slsr_cand_t basis; |
2309 | location_t loc; | |
f9453c07 | 2310 | |
9b92d12b BS |
2311 | /* Look up the LHS SSA name from C's basis. This will be the |
2312 | RHS1 of the adds we will introduce to create new phi arguments. */ | |
2313 | basis = lookup_cand (c->basis); | |
2314 | basis_name = gimple_assign_lhs (basis->cand_stmt); | |
f9453c07 | 2315 | |
9b92d12b BS |
2316 | /* Create a new phi statement which will represent C's true basis |
2317 | after the transformation is complete. */ | |
2318 | loc = gimple_location (c->cand_stmt); | |
2319 | name = create_phi_basis (c, lookup_cand (c->def_phi)->cand_stmt, | |
2320 | basis_name, loc, KNOWN_STRIDE); | |
2321 | /* Replace C with an add of the new basis phi and a constant. */ | |
807e902e | 2322 | widest_int bump = c->index * wi::to_widest (c->stride); |
f9453c07 | 2323 | |
a7a7d10e | 2324 | replace_mult_candidate (c, name, bump); |
f9453c07 | 2325 | } |
88ca9ea1 | 2326 | |
9b92d12b BS |
2327 | /* Compute the expected costs of inserting basis adjustments for |
2328 | candidate C with phi-definition PHI. The cost of inserting | |
2329 | one adjustment is given by ONE_ADD_COST. If PHI has arguments | |
2330 | which are themselves phi results, recursively calculate costs | |
2331 | for those phis as well. */ | |
2332 | ||
2333 | static int | |
355fe088 | 2334 | phi_add_costs (gimple *phi, slsr_cand_t c, int one_add_cost) |
88ca9ea1 BS |
2335 | { |
2336 | unsigned i; | |
9b92d12b | 2337 | int cost = 0; |
5b3d5f76 | 2338 | slsr_cand_t phi_cand = *stmt_cand_map->get (phi); |
88ca9ea1 | 2339 | |
0100cd3f BS |
2340 | /* If we work our way back to a phi that isn't dominated by the hidden |
2341 | basis, this isn't a candidate for replacement. Indicate this by | |
2342 | returning an unreasonably high cost. It's not easy to detect | |
2343 | these situations when determining the basis, so we defer the | |
2344 | decision until now. */ | |
2345 | basic_block phi_bb = gimple_bb (phi); | |
2346 | slsr_cand_t basis = lookup_cand (c->basis); | |
2347 | basic_block basis_bb = gimple_bb (basis->cand_stmt); | |
2348 | ||
2349 | if (phi_bb == basis_bb || !dominated_by_p (CDI_DOMINATORS, phi_bb, basis_bb)) | |
2350 | return COST_INFINITE; | |
2351 | ||
9b92d12b BS |
2352 | for (i = 0; i < gimple_phi_num_args (phi); i++) |
2353 | { | |
2354 | tree arg = gimple_phi_arg_def (phi, i); | |
2355 | ||
2356 | if (arg != phi_cand->base_expr) | |
2357 | { | |
355fe088 | 2358 | gimple *arg_def = SSA_NAME_DEF_STMT (arg); |
9b92d12b BS |
2359 | |
2360 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
2361 | cost += phi_add_costs (arg_def, c, one_add_cost); | |
2362 | else | |
2363 | { | |
2364 | slsr_cand_t arg_cand = base_cand_from_table (arg); | |
2365 | ||
2366 | if (arg_cand->index != c->index) | |
2367 | cost += one_add_cost; | |
2368 | } | |
2369 | } | |
2370 | } | |
2371 | ||
2372 | return cost; | |
88ca9ea1 BS |
2373 | } |
2374 | ||
9b92d12b BS |
2375 | /* For candidate C, each sibling of candidate C, and each dependent of |
2376 | candidate C, determine whether the candidate is dependent upon a | |
2377 | phi that hides its basis. If not, replace the candidate unconditionally. | |
2378 | Otherwise, determine whether the cost of introducing compensation code | |
2379 | for the candidate is offset by the gains from strength reduction. If | |
2380 | so, replace the candidate and introduce the compensation code. */ | |
2381 | ||
2382 | static void | |
2383 | replace_uncond_cands_and_profitable_phis (slsr_cand_t c) | |
2384 | { | |
2385 | if (phi_dependent_cand_p (c)) | |
2386 | { | |
2387 | if (c->kind == CAND_MULT) | |
2388 | { | |
2389 | /* A candidate dependent upon a phi will replace a multiply by | |
2390 | a constant with an add, and will insert at most one add for | |
2391 | each phi argument. Add these costs with the potential dead-code | |
2392 | savings to determine profitability. */ | |
2393 | bool speed = optimize_bb_for_speed_p (gimple_bb (c->cand_stmt)); | |
2394 | int mult_savings = stmt_cost (c->cand_stmt, speed); | |
355fe088 | 2395 | gimple *phi = lookup_cand (c->def_phi)->cand_stmt; |
9b92d12b BS |
2396 | tree phi_result = gimple_phi_result (phi); |
2397 | int one_add_cost = add_cost (speed, | |
2398 | TYPE_MODE (TREE_TYPE (phi_result))); | |
2399 | int add_costs = one_add_cost + phi_add_costs (phi, c, one_add_cost); | |
2400 | int cost = add_costs - mult_savings - c->dead_savings; | |
2401 | ||
2402 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2403 | { | |
2404 | fprintf (dump_file, " Conditional candidate %d:\n", c->cand_num); | |
2405 | fprintf (dump_file, " add_costs = %d\n", add_costs); | |
2406 | fprintf (dump_file, " mult_savings = %d\n", mult_savings); | |
2407 | fprintf (dump_file, " dead_savings = %d\n", c->dead_savings); | |
2408 | fprintf (dump_file, " cost = %d\n", cost); | |
2409 | if (cost <= COST_NEUTRAL) | |
2410 | fputs (" Replacing...\n", dump_file); | |
2411 | else | |
2412 | fputs (" Not replaced.\n", dump_file); | |
2413 | } | |
2414 | ||
2415 | if (cost <= COST_NEUTRAL) | |
2416 | replace_conditional_candidate (c); | |
2417 | } | |
2418 | } | |
2419 | else | |
2420 | replace_unconditional_candidate (c); | |
2421 | ||
2422 | if (c->sibling) | |
2423 | replace_uncond_cands_and_profitable_phis (lookup_cand (c->sibling)); | |
2424 | ||
2425 | if (c->dependent) | |
2426 | replace_uncond_cands_and_profitable_phis (lookup_cand (c->dependent)); | |
2427 | } | |
2428 | \f | |
88ca9ea1 BS |
2429 | /* Count the number of candidates in the tree rooted at C that have |
2430 | not already been replaced under other interpretations. */ | |
2431 | ||
1dc3d6e9 | 2432 | static int |
88ca9ea1 BS |
2433 | count_candidates (slsr_cand_t c) |
2434 | { | |
2435 | unsigned count = cand_already_replaced (c) ? 0 : 1; | |
2436 | ||
2437 | if (c->sibling) | |
2438 | count += count_candidates (lookup_cand (c->sibling)); | |
2439 | ||
2440 | if (c->dependent) | |
2441 | count += count_candidates (lookup_cand (c->dependent)); | |
2442 | ||
2443 | return count; | |
2444 | } | |
2445 | ||
2446 | /* Increase the count of INCREMENT by one in the increment vector. | |
9b92d12b BS |
2447 | INCREMENT is associated with candidate C. If INCREMENT is to be |
2448 | conditionally executed as part of a conditional candidate replacement, | |
2449 | IS_PHI_ADJUST is true, otherwise false. If an initializer | |
88ca9ea1 BS |
2450 | T_0 = stride * I is provided by a candidate that dominates all |
2451 | candidates with the same increment, also record T_0 for subsequent use. */ | |
2452 | ||
2453 | static void | |
807e902e | 2454 | record_increment (slsr_cand_t c, widest_int increment, bool is_phi_adjust) |
88ca9ea1 BS |
2455 | { |
2456 | bool found = false; | |
2457 | unsigned i; | |
2458 | ||
2459 | /* Treat increments that differ only in sign as identical so as to | |
2460 | share initializers, unless we are generating pointer arithmetic. */ | |
807e902e | 2461 | if (!address_arithmetic_p && wi::neg_p (increment)) |
27bcd47c | 2462 | increment = -increment; |
88ca9ea1 BS |
2463 | |
2464 | for (i = 0; i < incr_vec_len; i++) | |
2465 | { | |
27bcd47c | 2466 | if (incr_vec[i].incr == increment) |
88ca9ea1 BS |
2467 | { |
2468 | incr_vec[i].count++; | |
2469 | found = true; | |
2470 | ||
2471 | /* If we previously recorded an initializer that doesn't | |
2472 | dominate this candidate, it's not going to be useful to | |
2473 | us after all. */ | |
2474 | if (incr_vec[i].initializer | |
2475 | && !dominated_by_p (CDI_DOMINATORS, | |
2476 | gimple_bb (c->cand_stmt), | |
2477 | incr_vec[i].init_bb)) | |
2478 | { | |
2479 | incr_vec[i].initializer = NULL_TREE; | |
2480 | incr_vec[i].init_bb = NULL; | |
2481 | } | |
2482 | ||
2483 | break; | |
2484 | } | |
2485 | } | |
2486 | ||
7bf55a70 | 2487 | if (!found && incr_vec_len < MAX_INCR_VEC_LEN - 1) |
88ca9ea1 BS |
2488 | { |
2489 | /* The first time we see an increment, create the entry for it. | |
2490 | If this is the root candidate which doesn't have a basis, set | |
2491 | the count to zero. We're only processing it so it can possibly | |
2492 | provide an initializer for other candidates. */ | |
2493 | incr_vec[incr_vec_len].incr = increment; | |
9b92d12b | 2494 | incr_vec[incr_vec_len].count = c->basis || is_phi_adjust ? 1 : 0; |
88ca9ea1 BS |
2495 | incr_vec[incr_vec_len].cost = COST_INFINITE; |
2496 | ||
2497 | /* Optimistically record the first occurrence of this increment | |
2498 | as providing an initializer (if it does); we will revise this | |
2499 | opinion later if it doesn't dominate all other occurrences. | |
9b92d12b BS |
2500 | Exception: increments of -1, 0, 1 never need initializers; |
2501 | and phi adjustments don't ever provide initializers. */ | |
88ca9ea1 | 2502 | if (c->kind == CAND_ADD |
9b92d12b | 2503 | && !is_phi_adjust |
27bcd47c | 2504 | && c->index == increment |
032c80e9 | 2505 | && (increment > 1 || increment < -1) |
7b8265ba JJ |
2506 | && (gimple_assign_rhs_code (c->cand_stmt) == PLUS_EXPR |
2507 | || gimple_assign_rhs_code (c->cand_stmt) == POINTER_PLUS_EXPR)) | |
88ca9ea1 | 2508 | { |
7b8265ba | 2509 | tree t0 = NULL_TREE; |
88ca9ea1 BS |
2510 | tree rhs1 = gimple_assign_rhs1 (c->cand_stmt); |
2511 | tree rhs2 = gimple_assign_rhs2 (c->cand_stmt); | |
2512 | if (operand_equal_p (rhs1, c->base_expr, 0)) | |
2513 | t0 = rhs2; | |
7b8265ba | 2514 | else if (operand_equal_p (rhs2, c->base_expr, 0)) |
88ca9ea1 | 2515 | t0 = rhs1; |
7b8265ba JJ |
2516 | if (t0 |
2517 | && SSA_NAME_DEF_STMT (t0) | |
2518 | && gimple_bb (SSA_NAME_DEF_STMT (t0))) | |
88ca9ea1 BS |
2519 | { |
2520 | incr_vec[incr_vec_len].initializer = t0; | |
2521 | incr_vec[incr_vec_len++].init_bb | |
2522 | = gimple_bb (SSA_NAME_DEF_STMT (t0)); | |
2523 | } | |
2524 | else | |
2525 | { | |
2526 | incr_vec[incr_vec_len].initializer = NULL_TREE; | |
2527 | incr_vec[incr_vec_len++].init_bb = NULL; | |
2528 | } | |
2529 | } | |
2530 | else | |
2531 | { | |
2532 | incr_vec[incr_vec_len].initializer = NULL_TREE; | |
2533 | incr_vec[incr_vec_len++].init_bb = NULL; | |
2534 | } | |
2535 | } | |
2536 | } | |
2537 | ||
9b92d12b BS |
2538 | /* Given phi statement PHI that hides a candidate from its BASIS, find |
2539 | the increments along each incoming arc (recursively handling additional | |
2540 | phis that may be present) and record them. These increments are the | |
2541 | difference in index between the index-adjusting statements and the | |
2542 | index of the basis. */ | |
2543 | ||
2544 | static void | |
355fe088 | 2545 | record_phi_increments (slsr_cand_t basis, gimple *phi) |
9b92d12b BS |
2546 | { |
2547 | unsigned i; | |
5b3d5f76 | 2548 | slsr_cand_t phi_cand = *stmt_cand_map->get (phi); |
9b92d12b BS |
2549 | |
2550 | for (i = 0; i < gimple_phi_num_args (phi); i++) | |
2551 | { | |
2552 | tree arg = gimple_phi_arg_def (phi, i); | |
2553 | ||
2554 | if (!operand_equal_p (arg, phi_cand->base_expr, 0)) | |
2555 | { | |
355fe088 | 2556 | gimple *arg_def = SSA_NAME_DEF_STMT (arg); |
9b92d12b BS |
2557 | |
2558 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
2559 | record_phi_increments (basis, arg_def); | |
2560 | else | |
2561 | { | |
2562 | slsr_cand_t arg_cand = base_cand_from_table (arg); | |
807e902e | 2563 | widest_int diff = arg_cand->index - basis->index; |
9b92d12b BS |
2564 | record_increment (arg_cand, diff, PHI_ADJUST); |
2565 | } | |
2566 | } | |
2567 | } | |
2568 | } | |
2569 | ||
88ca9ea1 BS |
2570 | /* Determine how many times each unique increment occurs in the set |
2571 | of candidates rooted at C's parent, recording the data in the | |
2572 | increment vector. For each unique increment I, if an initializer | |
2573 | T_0 = stride * I is provided by a candidate that dominates all | |
2574 | candidates with the same increment, also record T_0 for subsequent | |
2575 | use. */ | |
2576 | ||
2577 | static void | |
2578 | record_increments (slsr_cand_t c) | |
2579 | { | |
2580 | if (!cand_already_replaced (c)) | |
9b92d12b BS |
2581 | { |
2582 | if (!phi_dependent_cand_p (c)) | |
2583 | record_increment (c, cand_increment (c), NOT_PHI_ADJUST); | |
2584 | else | |
2585 | { | |
2586 | /* A candidate with a basis hidden by a phi will have one | |
2587 | increment for its relationship to the index represented by | |
2588 | the phi, and potentially additional increments along each | |
2589 | incoming edge. For the root of the dependency tree (which | |
2590 | has no basis), process just the initial index in case it has | |
2591 | an initializer that can be used by subsequent candidates. */ | |
2592 | record_increment (c, c->index, NOT_PHI_ADJUST); | |
2593 | ||
2594 | if (c->basis) | |
2595 | record_phi_increments (lookup_cand (c->basis), | |
2596 | lookup_cand (c->def_phi)->cand_stmt); | |
2597 | } | |
2598 | } | |
88ca9ea1 BS |
2599 | |
2600 | if (c->sibling) | |
2601 | record_increments (lookup_cand (c->sibling)); | |
2602 | ||
2603 | if (c->dependent) | |
2604 | record_increments (lookup_cand (c->dependent)); | |
2605 | } | |
2606 | ||
9b92d12b BS |
2607 | /* Add up and return the costs of introducing add statements that |
2608 | require the increment INCR on behalf of candidate C and phi | |
2609 | statement PHI. Accumulate into *SAVINGS the potential savings | |
2610 | from removing existing statements that feed PHI and have no other | |
2611 | uses. */ | |
2612 | ||
2613 | static int | |
355fe088 TS |
2614 | phi_incr_cost (slsr_cand_t c, const widest_int &incr, gimple *phi, |
2615 | int *savings) | |
9b92d12b BS |
2616 | { |
2617 | unsigned i; | |
2618 | int cost = 0; | |
2619 | slsr_cand_t basis = lookup_cand (c->basis); | |
5b3d5f76 | 2620 | slsr_cand_t phi_cand = *stmt_cand_map->get (phi); |
9b92d12b BS |
2621 | |
2622 | for (i = 0; i < gimple_phi_num_args (phi); i++) | |
2623 | { | |
2624 | tree arg = gimple_phi_arg_def (phi, i); | |
2625 | ||
2626 | if (!operand_equal_p (arg, phi_cand->base_expr, 0)) | |
2627 | { | |
355fe088 | 2628 | gimple *arg_def = SSA_NAME_DEF_STMT (arg); |
9b92d12b BS |
2629 | |
2630 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
2631 | { | |
2632 | int feeding_savings = 0; | |
2633 | cost += phi_incr_cost (c, incr, arg_def, &feeding_savings); | |
2634 | if (has_single_use (gimple_phi_result (arg_def))) | |
2635 | *savings += feeding_savings; | |
2636 | } | |
2637 | else | |
2638 | { | |
2639 | slsr_cand_t arg_cand = base_cand_from_table (arg); | |
807e902e | 2640 | widest_int diff = arg_cand->index - basis->index; |
9b92d12b BS |
2641 | |
2642 | if (incr == diff) | |
2643 | { | |
2644 | tree basis_lhs = gimple_assign_lhs (basis->cand_stmt); | |
2645 | tree lhs = gimple_assign_lhs (arg_cand->cand_stmt); | |
2646 | cost += add_cost (true, TYPE_MODE (TREE_TYPE (basis_lhs))); | |
2647 | if (has_single_use (lhs)) | |
2648 | *savings += stmt_cost (arg_cand->cand_stmt, true); | |
2649 | } | |
2650 | } | |
2651 | } | |
2652 | } | |
2653 | ||
2654 | return cost; | |
2655 | } | |
2656 | ||
88ca9ea1 BS |
2657 | /* Return the first candidate in the tree rooted at C that has not |
2658 | already been replaced, favoring siblings over dependents. */ | |
2659 | ||
2660 | static slsr_cand_t | |
2661 | unreplaced_cand_in_tree (slsr_cand_t c) | |
2662 | { | |
2663 | if (!cand_already_replaced (c)) | |
2664 | return c; | |
2665 | ||
2666 | if (c->sibling) | |
2667 | { | |
2668 | slsr_cand_t sib = unreplaced_cand_in_tree (lookup_cand (c->sibling)); | |
2669 | if (sib) | |
2670 | return sib; | |
2671 | } | |
2672 | ||
2673 | if (c->dependent) | |
2674 | { | |
2675 | slsr_cand_t dep = unreplaced_cand_in_tree (lookup_cand (c->dependent)); | |
2676 | if (dep) | |
2677 | return dep; | |
2678 | } | |
2679 | ||
2680 | return NULL; | |
2681 | } | |
2682 | ||
2683 | /* Return TRUE if the candidates in the tree rooted at C should be | |
2684 | optimized for speed, else FALSE. We estimate this based on the block | |
2685 | containing the most dominant candidate in the tree that has not yet | |
2686 | been replaced. */ | |
2687 | ||
2688 | static bool | |
2689 | optimize_cands_for_speed_p (slsr_cand_t c) | |
2690 | { | |
2691 | slsr_cand_t c2 = unreplaced_cand_in_tree (c); | |
2692 | gcc_assert (c2); | |
2693 | return optimize_bb_for_speed_p (gimple_bb (c2->cand_stmt)); | |
2694 | } | |
2695 | ||
2696 | /* Add COST_IN to the lowest cost of any dependent path starting at | |
2697 | candidate C or any of its siblings, counting only candidates along | |
2698 | such paths with increment INCR. Assume that replacing a candidate | |
2699 | reduces cost by REPL_SAVINGS. Also account for savings from any | |
9b92d12b BS |
2700 | statements that would go dead. If COUNT_PHIS is true, include |
2701 | costs of introducing feeding statements for conditional candidates. */ | |
88ca9ea1 BS |
2702 | |
2703 | static int | |
9b92d12b | 2704 | lowest_cost_path (int cost_in, int repl_savings, slsr_cand_t c, |
807e902e | 2705 | const widest_int &incr, bool count_phis) |
88ca9ea1 | 2706 | { |
9b92d12b | 2707 | int local_cost, sib_cost, savings = 0; |
807e902e | 2708 | widest_int cand_incr = cand_abs_increment (c); |
88ca9ea1 BS |
2709 | |
2710 | if (cand_already_replaced (c)) | |
2711 | local_cost = cost_in; | |
27bcd47c | 2712 | else if (incr == cand_incr) |
88ca9ea1 BS |
2713 | local_cost = cost_in - repl_savings - c->dead_savings; |
2714 | else | |
2715 | local_cost = cost_in - c->dead_savings; | |
2716 | ||
9b92d12b BS |
2717 | if (count_phis |
2718 | && phi_dependent_cand_p (c) | |
2719 | && !cand_already_replaced (c)) | |
2720 | { | |
355fe088 | 2721 | gimple *phi = lookup_cand (c->def_phi)->cand_stmt; |
9b92d12b BS |
2722 | local_cost += phi_incr_cost (c, incr, phi, &savings); |
2723 | ||
2724 | if (has_single_use (gimple_phi_result (phi))) | |
2725 | local_cost -= savings; | |
2726 | } | |
2727 | ||
88ca9ea1 BS |
2728 | if (c->dependent) |
2729 | local_cost = lowest_cost_path (local_cost, repl_savings, | |
9b92d12b BS |
2730 | lookup_cand (c->dependent), incr, |
2731 | count_phis); | |
88ca9ea1 BS |
2732 | |
2733 | if (c->sibling) | |
2734 | { | |
2735 | sib_cost = lowest_cost_path (cost_in, repl_savings, | |
9b92d12b BS |
2736 | lookup_cand (c->sibling), incr, |
2737 | count_phis); | |
88ca9ea1 BS |
2738 | local_cost = MIN (local_cost, sib_cost); |
2739 | } | |
2740 | ||
2741 | return local_cost; | |
2742 | } | |
2743 | ||
2744 | /* Compute the total savings that would accrue from all replacements | |
2745 | in the candidate tree rooted at C, counting only candidates with | |
2746 | increment INCR. Assume that replacing a candidate reduces cost | |
2747 | by REPL_SAVINGS. Also account for savings from statements that | |
2748 | would go dead. */ | |
2749 | ||
2750 | static int | |
807e902e | 2751 | total_savings (int repl_savings, slsr_cand_t c, const widest_int &incr, |
9b92d12b | 2752 | bool count_phis) |
88ca9ea1 BS |
2753 | { |
2754 | int savings = 0; | |
807e902e | 2755 | widest_int cand_incr = cand_abs_increment (c); |
88ca9ea1 | 2756 | |
27bcd47c | 2757 | if (incr == cand_incr && !cand_already_replaced (c)) |
88ca9ea1 BS |
2758 | savings += repl_savings + c->dead_savings; |
2759 | ||
9b92d12b BS |
2760 | if (count_phis |
2761 | && phi_dependent_cand_p (c) | |
2762 | && !cand_already_replaced (c)) | |
2763 | { | |
2764 | int phi_savings = 0; | |
355fe088 | 2765 | gimple *phi = lookup_cand (c->def_phi)->cand_stmt; |
9b92d12b BS |
2766 | savings -= phi_incr_cost (c, incr, phi, &phi_savings); |
2767 | ||
2768 | if (has_single_use (gimple_phi_result (phi))) | |
2769 | savings += phi_savings; | |
2770 | } | |
2771 | ||
88ca9ea1 | 2772 | if (c->dependent) |
9b92d12b BS |
2773 | savings += total_savings (repl_savings, lookup_cand (c->dependent), incr, |
2774 | count_phis); | |
88ca9ea1 BS |
2775 | |
2776 | if (c->sibling) | |
9b92d12b BS |
2777 | savings += total_savings (repl_savings, lookup_cand (c->sibling), incr, |
2778 | count_phis); | |
88ca9ea1 BS |
2779 | |
2780 | return savings; | |
2781 | } | |
2782 | ||
2783 | /* Use target-specific costs to determine and record which increments | |
2784 | in the current candidate tree are profitable to replace, assuming | |
2785 | MODE and SPEED. FIRST_DEP is the first dependent of the root of | |
2786 | the candidate tree. | |
2787 | ||
2788 | One slight limitation here is that we don't account for the possible | |
2789 | introduction of casts in some cases. See replace_one_candidate for | |
2790 | the cases where these are introduced. This should probably be cleaned | |
2791 | up sometime. */ | |
2792 | ||
2793 | static void | |
ef4bddc2 | 2794 | analyze_increments (slsr_cand_t first_dep, machine_mode mode, bool speed) |
88ca9ea1 BS |
2795 | { |
2796 | unsigned i; | |
2797 | ||
2798 | for (i = 0; i < incr_vec_len; i++) | |
2799 | { | |
27bcd47c | 2800 | HOST_WIDE_INT incr = incr_vec[i].incr.to_shwi (); |
88ca9ea1 BS |
2801 | |
2802 | /* If somehow this increment is bigger than a HWI, we won't | |
2803 | be optimizing candidates that use it. And if the increment | |
2804 | has a count of zero, nothing will be done with it. */ | |
807e902e | 2805 | if (!wi::fits_shwi_p (incr_vec[i].incr) || !incr_vec[i].count) |
88ca9ea1 BS |
2806 | incr_vec[i].cost = COST_INFINITE; |
2807 | ||
2808 | /* Increments of 0, 1, and -1 are always profitable to replace, | |
2809 | because they always replace a multiply or add with an add or | |
2810 | copy, and may cause one or more existing instructions to go | |
2811 | dead. Exception: -1 can't be assumed to be profitable for | |
2812 | pointer addition. */ | |
2813 | else if (incr == 0 | |
2814 | || incr == 1 | |
2815 | || (incr == -1 | |
2816 | && (gimple_assign_rhs_code (first_dep->cand_stmt) | |
2817 | != POINTER_PLUS_EXPR))) | |
2818 | incr_vec[i].cost = COST_NEUTRAL; | |
2819 | ||
6b5eea61 BS |
2820 | /* FORNOW: If we need to add an initializer, give up if a cast from |
2821 | the candidate's type to its stride's type can lose precision. | |
2822 | This could eventually be handled better by expressly retaining the | |
2823 | result of a cast to a wider type in the stride. Example: | |
2824 | ||
2825 | short int _1; | |
2826 | _2 = (int) _1; | |
2827 | _3 = _2 * 10; | |
2828 | _4 = x + _3; ADD: x + (10 * _1) : int | |
2829 | _5 = _2 * 15; | |
2830 | _6 = x + _3; ADD: x + (15 * _1) : int | |
2831 | ||
2832 | Right now replacing _6 would cause insertion of an initializer | |
2833 | of the form "short int T = _1 * 5;" followed by a cast to | |
2834 | int, which could overflow incorrectly. Had we recorded _2 or | |
2835 | (int)_1 as the stride, this wouldn't happen. However, doing | |
2836 | this breaks other opportunities, so this will require some | |
2837 | care. */ | |
2838 | else if (!incr_vec[i].initializer | |
2839 | && TREE_CODE (first_dep->stride) != INTEGER_CST | |
2840 | && !legal_cast_p_1 (first_dep->stride, | |
2841 | gimple_assign_lhs (first_dep->cand_stmt))) | |
2842 | ||
2843 | incr_vec[i].cost = COST_INFINITE; | |
2844 | ||
50251425 BS |
2845 | /* If we need to add an initializer, make sure we don't introduce |
2846 | a multiply by a pointer type, which can happen in certain cast | |
2847 | scenarios. FIXME: When cleaning up these cast issues, we can | |
2848 | afford to introduce the multiply provided we cast out to an | |
2849 | unsigned int of appropriate size. */ | |
2850 | else if (!incr_vec[i].initializer | |
2851 | && TREE_CODE (first_dep->stride) != INTEGER_CST | |
2852 | && POINTER_TYPE_P (TREE_TYPE (first_dep->stride))) | |
2853 | ||
2854 | incr_vec[i].cost = COST_INFINITE; | |
2855 | ||
88ca9ea1 BS |
2856 | /* For any other increment, if this is a multiply candidate, we |
2857 | must introduce a temporary T and initialize it with | |
2858 | T_0 = stride * increment. When optimizing for speed, walk the | |
2859 | candidate tree to calculate the best cost reduction along any | |
2860 | path; if it offsets the fixed cost of inserting the initializer, | |
2861 | replacing the increment is profitable. When optimizing for | |
2862 | size, instead calculate the total cost reduction from replacing | |
2863 | all candidates with this increment. */ | |
2864 | else if (first_dep->kind == CAND_MULT) | |
2865 | { | |
2866 | int cost = mult_by_coeff_cost (incr, mode, speed); | |
2867 | int repl_savings = mul_cost (speed, mode) - add_cost (speed, mode); | |
2868 | if (speed) | |
2869 | cost = lowest_cost_path (cost, repl_savings, first_dep, | |
9b92d12b | 2870 | incr_vec[i].incr, COUNT_PHIS); |
88ca9ea1 | 2871 | else |
9b92d12b BS |
2872 | cost -= total_savings (repl_savings, first_dep, incr_vec[i].incr, |
2873 | COUNT_PHIS); | |
88ca9ea1 BS |
2874 | |
2875 | incr_vec[i].cost = cost; | |
2876 | } | |
2877 | ||
2878 | /* If this is an add candidate, the initializer may already | |
2879 | exist, so only calculate the cost of the initializer if it | |
2880 | doesn't. We are replacing one add with another here, so the | |
2881 | known replacement savings is zero. We will account for removal | |
2882 | of dead instructions in lowest_cost_path or total_savings. */ | |
2883 | else | |
2884 | { | |
2885 | int cost = 0; | |
2886 | if (!incr_vec[i].initializer) | |
2887 | cost = mult_by_coeff_cost (incr, mode, speed); | |
2888 | ||
2889 | if (speed) | |
9b92d12b BS |
2890 | cost = lowest_cost_path (cost, 0, first_dep, incr_vec[i].incr, |
2891 | DONT_COUNT_PHIS); | |
88ca9ea1 | 2892 | else |
9b92d12b BS |
2893 | cost -= total_savings (0, first_dep, incr_vec[i].incr, |
2894 | DONT_COUNT_PHIS); | |
88ca9ea1 BS |
2895 | |
2896 | incr_vec[i].cost = cost; | |
2897 | } | |
2898 | } | |
2899 | } | |
2900 | ||
2901 | /* Return the nearest common dominator of BB1 and BB2. If the blocks | |
2902 | are identical, return the earlier of C1 and C2 in *WHERE. Otherwise, | |
2903 | if the NCD matches BB1, return C1 in *WHERE; if the NCD matches BB2, | |
2904 | return C2 in *WHERE; and if the NCD matches neither, return NULL in | |
2905 | *WHERE. Note: It is possible for one of C1 and C2 to be NULL. */ | |
2906 | ||
2907 | static basic_block | |
2908 | ncd_for_two_cands (basic_block bb1, basic_block bb2, | |
2909 | slsr_cand_t c1, slsr_cand_t c2, slsr_cand_t *where) | |
2910 | { | |
2911 | basic_block ncd; | |
2912 | ||
2913 | if (!bb1) | |
2914 | { | |
2915 | *where = c2; | |
2916 | return bb2; | |
2917 | } | |
2918 | ||
2919 | if (!bb2) | |
2920 | { | |
2921 | *where = c1; | |
2922 | return bb1; | |
2923 | } | |
2924 | ||
2925 | ncd = nearest_common_dominator (CDI_DOMINATORS, bb1, bb2); | |
2926 | ||
2927 | /* If both candidates are in the same block, the earlier | |
2928 | candidate wins. */ | |
2929 | if (bb1 == ncd && bb2 == ncd) | |
2930 | { | |
2931 | if (!c1 || (c2 && c2->cand_num < c1->cand_num)) | |
2932 | *where = c2; | |
2933 | else | |
2934 | *where = c1; | |
2935 | } | |
2936 | ||
2937 | /* Otherwise, if one of them produced a candidate in the | |
2938 | dominator, that one wins. */ | |
2939 | else if (bb1 == ncd) | |
2940 | *where = c1; | |
2941 | ||
2942 | else if (bb2 == ncd) | |
2943 | *where = c2; | |
2944 | ||
2945 | /* If neither matches the dominator, neither wins. */ | |
2946 | else | |
2947 | *where = NULL; | |
2948 | ||
2949 | return ncd; | |
2950 | } | |
2951 | ||
9b92d12b BS |
2952 | /* Consider all candidates that feed PHI. Find the nearest common |
2953 | dominator of those candidates requiring the given increment INCR. | |
2954 | Further find and return the nearest common dominator of this result | |
2955 | with block NCD. If the returned block contains one or more of the | |
2956 | candidates, return the earliest candidate in the block in *WHERE. */ | |
2957 | ||
2958 | static basic_block | |
538dd0b7 | 2959 | ncd_with_phi (slsr_cand_t c, const widest_int &incr, gphi *phi, |
9b92d12b BS |
2960 | basic_block ncd, slsr_cand_t *where) |
2961 | { | |
2962 | unsigned i; | |
2963 | slsr_cand_t basis = lookup_cand (c->basis); | |
5b3d5f76 | 2964 | slsr_cand_t phi_cand = *stmt_cand_map->get (phi); |
9b92d12b BS |
2965 | |
2966 | for (i = 0; i < gimple_phi_num_args (phi); i++) | |
2967 | { | |
2968 | tree arg = gimple_phi_arg_def (phi, i); | |
2969 | ||
2970 | if (!operand_equal_p (arg, phi_cand->base_expr, 0)) | |
2971 | { | |
355fe088 | 2972 | gimple *arg_def = SSA_NAME_DEF_STMT (arg); |
9b92d12b BS |
2973 | |
2974 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
538dd0b7 DM |
2975 | ncd = ncd_with_phi (c, incr, as_a <gphi *> (arg_def), ncd, |
2976 | where); | |
9b92d12b BS |
2977 | else |
2978 | { | |
2979 | slsr_cand_t arg_cand = base_cand_from_table (arg); | |
807e902e | 2980 | widest_int diff = arg_cand->index - basis->index; |
1e386bb8 | 2981 | basic_block pred = gimple_phi_arg_edge (phi, i)->src; |
9b92d12b BS |
2982 | |
2983 | if ((incr == diff) || (!address_arithmetic_p && incr == -diff)) | |
1e386bb8 | 2984 | ncd = ncd_for_two_cands (ncd, pred, *where, NULL, where); |
9b92d12b BS |
2985 | } |
2986 | } | |
2987 | } | |
2988 | ||
2989 | return ncd; | |
2990 | } | |
2991 | ||
2992 | /* Consider the candidate C together with any candidates that feed | |
2993 | C's phi dependence (if any). Find and return the nearest common | |
2994 | dominator of those candidates requiring the given increment INCR. | |
2995 | If the returned block contains one or more of the candidates, | |
2996 | return the earliest candidate in the block in *WHERE. */ | |
2997 | ||
2998 | static basic_block | |
807e902e | 2999 | ncd_of_cand_and_phis (slsr_cand_t c, const widest_int &incr, slsr_cand_t *where) |
9b92d12b BS |
3000 | { |
3001 | basic_block ncd = NULL; | |
3002 | ||
3003 | if (cand_abs_increment (c) == incr) | |
3004 | { | |
3005 | ncd = gimple_bb (c->cand_stmt); | |
3006 | *where = c; | |
3007 | } | |
3008 | ||
3009 | if (phi_dependent_cand_p (c)) | |
538dd0b7 DM |
3010 | ncd = ncd_with_phi (c, incr, |
3011 | as_a <gphi *> (lookup_cand (c->def_phi)->cand_stmt), | |
9b92d12b BS |
3012 | ncd, where); |
3013 | ||
3014 | return ncd; | |
3015 | } | |
3016 | ||
88ca9ea1 BS |
3017 | /* Consider all candidates in the tree rooted at C for which INCR |
3018 | represents the required increment of C relative to its basis. | |
3019 | Find and return the basic block that most nearly dominates all | |
3020 | such candidates. If the returned block contains one or more of | |
3021 | the candidates, return the earliest candidate in the block in | |
3022 | *WHERE. */ | |
3023 | ||
3024 | static basic_block | |
807e902e | 3025 | nearest_common_dominator_for_cands (slsr_cand_t c, const widest_int &incr, |
88ca9ea1 BS |
3026 | slsr_cand_t *where) |
3027 | { | |
3028 | basic_block sib_ncd = NULL, dep_ncd = NULL, this_ncd = NULL, ncd; | |
3029 | slsr_cand_t sib_where = NULL, dep_where = NULL, this_where = NULL, new_where; | |
88ca9ea1 BS |
3030 | |
3031 | /* First find the NCD of all siblings and dependents. */ | |
3032 | if (c->sibling) | |
3033 | sib_ncd = nearest_common_dominator_for_cands (lookup_cand (c->sibling), | |
3034 | incr, &sib_where); | |
3035 | if (c->dependent) | |
3036 | dep_ncd = nearest_common_dominator_for_cands (lookup_cand (c->dependent), | |
3037 | incr, &dep_where); | |
3038 | if (!sib_ncd && !dep_ncd) | |
3039 | { | |
3040 | new_where = NULL; | |
3041 | ncd = NULL; | |
3042 | } | |
3043 | else if (sib_ncd && !dep_ncd) | |
3044 | { | |
3045 | new_where = sib_where; | |
3046 | ncd = sib_ncd; | |
3047 | } | |
3048 | else if (dep_ncd && !sib_ncd) | |
3049 | { | |
3050 | new_where = dep_where; | |
3051 | ncd = dep_ncd; | |
3052 | } | |
3053 | else | |
3054 | ncd = ncd_for_two_cands (sib_ncd, dep_ncd, sib_where, | |
3055 | dep_where, &new_where); | |
3056 | ||
3057 | /* If the candidate's increment doesn't match the one we're interested | |
9b92d12b BS |
3058 | in (and nor do any increments for feeding defs of a phi-dependence), |
3059 | then the result depends only on siblings and dependents. */ | |
3060 | this_ncd = ncd_of_cand_and_phis (c, incr, &this_where); | |
88ca9ea1 | 3061 | |
9b92d12b | 3062 | if (!this_ncd || cand_already_replaced (c)) |
88ca9ea1 BS |
3063 | { |
3064 | *where = new_where; | |
3065 | return ncd; | |
3066 | } | |
3067 | ||
3068 | /* Otherwise, compare this candidate with the result from all siblings | |
3069 | and dependents. */ | |
88ca9ea1 BS |
3070 | ncd = ncd_for_two_cands (ncd, this_ncd, new_where, this_where, where); |
3071 | ||
3072 | return ncd; | |
3073 | } | |
3074 | ||
3075 | /* Return TRUE if the increment indexed by INDEX is profitable to replace. */ | |
3076 | ||
3077 | static inline bool | |
3078 | profitable_increment_p (unsigned index) | |
3079 | { | |
3080 | return (incr_vec[index].cost <= COST_NEUTRAL); | |
3081 | } | |
3082 | ||
3083 | /* For each profitable increment in the increment vector not equal to | |
3084 | 0 or 1 (or -1, for non-pointer arithmetic), find the nearest common | |
3085 | dominator of all statements in the candidate chain rooted at C | |
3086 | that require that increment, and insert an initializer | |
3087 | T_0 = stride * increment at that location. Record T_0 with the | |
3088 | increment record. */ | |
3089 | ||
3090 | static void | |
3091 | insert_initializers (slsr_cand_t c) | |
3092 | { | |
3093 | unsigned i; | |
88ca9ea1 BS |
3094 | |
3095 | for (i = 0; i < incr_vec_len; i++) | |
3096 | { | |
3097 | basic_block bb; | |
3098 | slsr_cand_t where = NULL; | |
538dd0b7 | 3099 | gassign *init_stmt; |
88ca9ea1 | 3100 | tree stride_type, new_name, incr_tree; |
807e902e | 3101 | widest_int incr = incr_vec[i].incr; |
88ca9ea1 BS |
3102 | |
3103 | if (!profitable_increment_p (i) | |
807e902e KZ |
3104 | || incr == 1 |
3105 | || (incr == -1 | |
88ca9ea1 | 3106 | && gimple_assign_rhs_code (c->cand_stmt) != POINTER_PLUS_EXPR) |
807e902e | 3107 | || incr == 0) |
88ca9ea1 BS |
3108 | continue; |
3109 | ||
3110 | /* We may have already identified an existing initializer that | |
3111 | will suffice. */ | |
3112 | if (incr_vec[i].initializer) | |
3113 | { | |
3114 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3115 | { | |
3116 | fputs ("Using existing initializer: ", dump_file); | |
3117 | print_gimple_stmt (dump_file, | |
3118 | SSA_NAME_DEF_STMT (incr_vec[i].initializer), | |
3119 | 0, 0); | |
3120 | } | |
3121 | continue; | |
3122 | } | |
3123 | ||
3124 | /* Find the block that most closely dominates all candidates | |
3125 | with this increment. If there is at least one candidate in | |
3126 | that block, the earliest one will be returned in WHERE. */ | |
3127 | bb = nearest_common_dominator_for_cands (c, incr, &where); | |
3128 | ||
3129 | /* Create a new SSA name to hold the initializer's value. */ | |
3130 | stride_type = TREE_TYPE (c->stride); | |
a7a7d10e | 3131 | new_name = make_temp_ssa_name (stride_type, NULL, "slsr"); |
88ca9ea1 BS |
3132 | incr_vec[i].initializer = new_name; |
3133 | ||
3134 | /* Create the initializer and insert it in the latest possible | |
3135 | dominating position. */ | |
807e902e | 3136 | incr_tree = wide_int_to_tree (stride_type, incr); |
0d0e4a03 JJ |
3137 | init_stmt = gimple_build_assign (new_name, MULT_EXPR, |
3138 | c->stride, incr_tree); | |
88ca9ea1 BS |
3139 | if (where) |
3140 | { | |
3141 | gimple_stmt_iterator gsi = gsi_for_stmt (where->cand_stmt); | |
3142 | gsi_insert_before (&gsi, init_stmt, GSI_SAME_STMT); | |
3143 | gimple_set_location (init_stmt, gimple_location (where->cand_stmt)); | |
3144 | } | |
3145 | else | |
3146 | { | |
3147 | gimple_stmt_iterator gsi = gsi_last_bb (bb); | |
355fe088 | 3148 | gimple *basis_stmt = lookup_cand (c->basis)->cand_stmt; |
88ca9ea1 BS |
3149 | |
3150 | if (!gsi_end_p (gsi) && is_ctrl_stmt (gsi_stmt (gsi))) | |
3151 | gsi_insert_before (&gsi, init_stmt, GSI_SAME_STMT); | |
3152 | else | |
3153 | gsi_insert_after (&gsi, init_stmt, GSI_SAME_STMT); | |
3154 | ||
3155 | gimple_set_location (init_stmt, gimple_location (basis_stmt)); | |
3156 | } | |
3157 | ||
3158 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3159 | { | |
3160 | fputs ("Inserting initializer: ", dump_file); | |
3161 | print_gimple_stmt (dump_file, init_stmt, 0, 0); | |
3162 | } | |
3163 | } | |
3164 | } | |
3165 | ||
9b92d12b BS |
3166 | /* Return TRUE iff all required increments for candidates feeding PHI |
3167 | are profitable to replace on behalf of candidate C. */ | |
3168 | ||
3169 | static bool | |
355fe088 | 3170 | all_phi_incrs_profitable (slsr_cand_t c, gimple *phi) |
9b92d12b BS |
3171 | { |
3172 | unsigned i; | |
3173 | slsr_cand_t basis = lookup_cand (c->basis); | |
5b3d5f76 | 3174 | slsr_cand_t phi_cand = *stmt_cand_map->get (phi); |
9b92d12b BS |
3175 | |
3176 | for (i = 0; i < gimple_phi_num_args (phi); i++) | |
3177 | { | |
3178 | tree arg = gimple_phi_arg_def (phi, i); | |
3179 | ||
3180 | if (!operand_equal_p (arg, phi_cand->base_expr, 0)) | |
3181 | { | |
355fe088 | 3182 | gimple *arg_def = SSA_NAME_DEF_STMT (arg); |
9b92d12b BS |
3183 | |
3184 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
3185 | { | |
3186 | if (!all_phi_incrs_profitable (c, arg_def)) | |
3187 | return false; | |
3188 | } | |
3189 | else | |
3190 | { | |
7bf55a70 | 3191 | int j; |
9b92d12b | 3192 | slsr_cand_t arg_cand = base_cand_from_table (arg); |
807e902e | 3193 | widest_int increment = arg_cand->index - basis->index; |
9b92d12b | 3194 | |
807e902e | 3195 | if (!address_arithmetic_p && wi::neg_p (increment)) |
9b92d12b BS |
3196 | increment = -increment; |
3197 | ||
3198 | j = incr_vec_index (increment); | |
3199 | ||
3200 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3201 | { | |
3202 | fprintf (dump_file, " Conditional candidate %d, phi: ", | |
3203 | c->cand_num); | |
3204 | print_gimple_stmt (dump_file, phi, 0, 0); | |
3205 | fputs (" increment: ", dump_file); | |
807e902e | 3206 | print_decs (increment, dump_file); |
7bf55a70 BS |
3207 | if (j < 0) |
3208 | fprintf (dump_file, | |
3209 | "\n Not replaced; incr_vec overflow.\n"); | |
3210 | else { | |
3211 | fprintf (dump_file, "\n cost: %d\n", incr_vec[j].cost); | |
3212 | if (profitable_increment_p (j)) | |
3213 | fputs (" Replacing...\n", dump_file); | |
3214 | else | |
3215 | fputs (" Not replaced.\n", dump_file); | |
3216 | } | |
9b92d12b BS |
3217 | } |
3218 | ||
7bf55a70 | 3219 | if (j < 0 || !profitable_increment_p (j)) |
9b92d12b BS |
3220 | return false; |
3221 | } | |
3222 | } | |
3223 | } | |
3224 | ||
3225 | return true; | |
3226 | } | |
3227 | ||
88ca9ea1 BS |
3228 | /* Create a NOP_EXPR that copies FROM_EXPR into a new SSA name of |
3229 | type TO_TYPE, and insert it in front of the statement represented | |
3230 | by candidate C. Use *NEW_VAR to create the new SSA name. Return | |
3231 | the new SSA name. */ | |
3232 | ||
3233 | static tree | |
a7a7d10e | 3234 | introduce_cast_before_cand (slsr_cand_t c, tree to_type, tree from_expr) |
88ca9ea1 BS |
3235 | { |
3236 | tree cast_lhs; | |
538dd0b7 | 3237 | gassign *cast_stmt; |
88ca9ea1 BS |
3238 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); |
3239 | ||
a7a7d10e | 3240 | cast_lhs = make_temp_ssa_name (to_type, NULL, "slsr"); |
0d0e4a03 | 3241 | cast_stmt = gimple_build_assign (cast_lhs, NOP_EXPR, from_expr); |
88ca9ea1 BS |
3242 | gimple_set_location (cast_stmt, gimple_location (c->cand_stmt)); |
3243 | gsi_insert_before (&gsi, cast_stmt, GSI_SAME_STMT); | |
3244 | ||
3245 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3246 | { | |
3247 | fputs (" Inserting: ", dump_file); | |
3248 | print_gimple_stmt (dump_file, cast_stmt, 0, 0); | |
3249 | } | |
3250 | ||
3251 | return cast_lhs; | |
3252 | } | |
3253 | ||
3254 | /* Replace the RHS of the statement represented by candidate C with | |
3255 | NEW_CODE, NEW_RHS1, and NEW_RHS2, provided that to do so doesn't | |
3256 | leave C unchanged or just interchange its operands. The original | |
3257 | operation and operands are in OLD_CODE, OLD_RHS1, and OLD_RHS2. | |
3258 | If the replacement was made and we are doing a details dump, | |
3259 | return the revised statement, else NULL. */ | |
3260 | ||
355fe088 | 3261 | static gimple * |
88ca9ea1 BS |
3262 | replace_rhs_if_not_dup (enum tree_code new_code, tree new_rhs1, tree new_rhs2, |
3263 | enum tree_code old_code, tree old_rhs1, tree old_rhs2, | |
3264 | slsr_cand_t c) | |
3265 | { | |
3266 | if (new_code != old_code | |
3267 | || ((!operand_equal_p (new_rhs1, old_rhs1, 0) | |
3268 | || !operand_equal_p (new_rhs2, old_rhs2, 0)) | |
3269 | && (!operand_equal_p (new_rhs1, old_rhs2, 0) | |
3270 | || !operand_equal_p (new_rhs2, old_rhs1, 0)))) | |
3271 | { | |
3272 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
3273 | gimple_assign_set_rhs_with_ops (&gsi, new_code, new_rhs1, new_rhs2); | |
3274 | update_stmt (gsi_stmt (gsi)); | |
bb0d2039 | 3275 | c->cand_stmt = gsi_stmt (gsi); |
88ca9ea1 BS |
3276 | |
3277 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3278 | return gsi_stmt (gsi); | |
3279 | } | |
3280 | ||
3281 | else if (dump_file && (dump_flags & TDF_DETAILS)) | |
3282 | fputs (" (duplicate, not actually replacing)\n", dump_file); | |
3283 | ||
3284 | return NULL; | |
3285 | } | |
3286 | ||
3287 | /* Strength-reduce the statement represented by candidate C by replacing | |
3288 | it with an equivalent addition or subtraction. I is the index into | |
3289 | the increment vector identifying C's increment. NEW_VAR is used to | |
3290 | create a new SSA name if a cast needs to be introduced. BASIS_NAME | |
3291 | is the rhs1 to use in creating the add/subtract. */ | |
3292 | ||
3293 | static void | |
a7a7d10e | 3294 | replace_one_candidate (slsr_cand_t c, unsigned i, tree basis_name) |
88ca9ea1 | 3295 | { |
355fe088 | 3296 | gimple *stmt_to_print = NULL; |
88ca9ea1 BS |
3297 | tree orig_rhs1, orig_rhs2; |
3298 | tree rhs2; | |
3299 | enum tree_code orig_code, repl_code; | |
807e902e | 3300 | widest_int cand_incr; |
88ca9ea1 BS |
3301 | |
3302 | orig_code = gimple_assign_rhs_code (c->cand_stmt); | |
3303 | orig_rhs1 = gimple_assign_rhs1 (c->cand_stmt); | |
3304 | orig_rhs2 = gimple_assign_rhs2 (c->cand_stmt); | |
3305 | cand_incr = cand_increment (c); | |
3306 | ||
3307 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3308 | { | |
3309 | fputs ("Replacing: ", dump_file); | |
3310 | print_gimple_stmt (dump_file, c->cand_stmt, 0, 0); | |
3311 | stmt_to_print = c->cand_stmt; | |
3312 | } | |
3313 | ||
3314 | if (address_arithmetic_p) | |
3315 | repl_code = POINTER_PLUS_EXPR; | |
3316 | else | |
3317 | repl_code = PLUS_EXPR; | |
3318 | ||
3319 | /* If the increment has an initializer T_0, replace the candidate | |
3320 | statement with an add of the basis name and the initializer. */ | |
3321 | if (incr_vec[i].initializer) | |
3322 | { | |
3323 | tree init_type = TREE_TYPE (incr_vec[i].initializer); | |
3324 | tree orig_type = TREE_TYPE (orig_rhs2); | |
3325 | ||
3326 | if (types_compatible_p (orig_type, init_type)) | |
3327 | rhs2 = incr_vec[i].initializer; | |
3328 | else | |
3329 | rhs2 = introduce_cast_before_cand (c, orig_type, | |
a7a7d10e | 3330 | incr_vec[i].initializer); |
88ca9ea1 | 3331 | |
27bcd47c | 3332 | if (incr_vec[i].incr != cand_incr) |
88ca9ea1 BS |
3333 | { |
3334 | gcc_assert (repl_code == PLUS_EXPR); | |
3335 | repl_code = MINUS_EXPR; | |
3336 | } | |
3337 | ||
3338 | stmt_to_print = replace_rhs_if_not_dup (repl_code, basis_name, rhs2, | |
3339 | orig_code, orig_rhs1, orig_rhs2, | |
3340 | c); | |
3341 | } | |
3342 | ||
3343 | /* Otherwise, the increment is one of -1, 0, and 1. Replace | |
3344 | with a subtract of the stride from the basis name, a copy | |
3345 | from the basis name, or an add of the stride to the basis | |
3346 | name, respectively. It may be necessary to introduce a | |
3347 | cast (or reuse an existing cast). */ | |
807e902e | 3348 | else if (cand_incr == 1) |
88ca9ea1 BS |
3349 | { |
3350 | tree stride_type = TREE_TYPE (c->stride); | |
3351 | tree orig_type = TREE_TYPE (orig_rhs2); | |
3352 | ||
3353 | if (types_compatible_p (orig_type, stride_type)) | |
3354 | rhs2 = c->stride; | |
3355 | else | |
a7a7d10e | 3356 | rhs2 = introduce_cast_before_cand (c, orig_type, c->stride); |
88ca9ea1 BS |
3357 | |
3358 | stmt_to_print = replace_rhs_if_not_dup (repl_code, basis_name, rhs2, | |
3359 | orig_code, orig_rhs1, orig_rhs2, | |
3360 | c); | |
3361 | } | |
3362 | ||
807e902e | 3363 | else if (cand_incr == -1) |
88ca9ea1 BS |
3364 | { |
3365 | tree stride_type = TREE_TYPE (c->stride); | |
3366 | tree orig_type = TREE_TYPE (orig_rhs2); | |
3367 | gcc_assert (repl_code != POINTER_PLUS_EXPR); | |
3368 | ||
3369 | if (types_compatible_p (orig_type, stride_type)) | |
3370 | rhs2 = c->stride; | |
3371 | else | |
a7a7d10e | 3372 | rhs2 = introduce_cast_before_cand (c, orig_type, c->stride); |
88ca9ea1 BS |
3373 | |
3374 | if (orig_code != MINUS_EXPR | |
3375 | || !operand_equal_p (basis_name, orig_rhs1, 0) | |
3376 | || !operand_equal_p (rhs2, orig_rhs2, 0)) | |
3377 | { | |
3378 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
3379 | gimple_assign_set_rhs_with_ops (&gsi, MINUS_EXPR, basis_name, rhs2); | |
3380 | update_stmt (gsi_stmt (gsi)); | |
bb0d2039 | 3381 | c->cand_stmt = gsi_stmt (gsi); |
88ca9ea1 BS |
3382 | |
3383 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3384 | stmt_to_print = gsi_stmt (gsi); | |
3385 | } | |
3386 | else if (dump_file && (dump_flags & TDF_DETAILS)) | |
3387 | fputs (" (duplicate, not actually replacing)\n", dump_file); | |
3388 | } | |
3389 | ||
807e902e | 3390 | else if (cand_incr == 0) |
88ca9ea1 BS |
3391 | { |
3392 | tree lhs = gimple_assign_lhs (c->cand_stmt); | |
3393 | tree lhs_type = TREE_TYPE (lhs); | |
3394 | tree basis_type = TREE_TYPE (basis_name); | |
3395 | ||
3396 | if (types_compatible_p (lhs_type, basis_type)) | |
3397 | { | |
538dd0b7 | 3398 | gassign *copy_stmt = gimple_build_assign (lhs, basis_name); |
88ca9ea1 BS |
3399 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); |
3400 | gimple_set_location (copy_stmt, gimple_location (c->cand_stmt)); | |
3401 | gsi_replace (&gsi, copy_stmt, false); | |
0100cd3f | 3402 | c->cand_stmt = copy_stmt; |
88ca9ea1 BS |
3403 | |
3404 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3405 | stmt_to_print = copy_stmt; | |
3406 | } | |
3407 | else | |
3408 | { | |
3409 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
0d0e4a03 | 3410 | gassign *cast_stmt = gimple_build_assign (lhs, NOP_EXPR, basis_name); |
88ca9ea1 BS |
3411 | gimple_set_location (cast_stmt, gimple_location (c->cand_stmt)); |
3412 | gsi_replace (&gsi, cast_stmt, false); | |
0100cd3f | 3413 | c->cand_stmt = cast_stmt; |
88ca9ea1 BS |
3414 | |
3415 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3416 | stmt_to_print = cast_stmt; | |
3417 | } | |
3418 | } | |
3419 | else | |
3420 | gcc_unreachable (); | |
3421 | ||
3422 | if (dump_file && (dump_flags & TDF_DETAILS) && stmt_to_print) | |
3423 | { | |
3424 | fputs ("With: ", dump_file); | |
3425 | print_gimple_stmt (dump_file, stmt_to_print, 0, 0); | |
3426 | fputs ("\n", dump_file); | |
3427 | } | |
3428 | } | |
3429 | ||
3430 | /* For each candidate in the tree rooted at C, replace it with | |
3431 | an increment if such has been shown to be profitable. */ | |
3432 | ||
3433 | static void | |
3434 | replace_profitable_candidates (slsr_cand_t c) | |
3435 | { | |
3436 | if (!cand_already_replaced (c)) | |
3437 | { | |
807e902e | 3438 | widest_int increment = cand_abs_increment (c); |
88ca9ea1 | 3439 | enum tree_code orig_code = gimple_assign_rhs_code (c->cand_stmt); |
7bf55a70 | 3440 | int i; |
88ca9ea1 BS |
3441 | |
3442 | i = incr_vec_index (increment); | |
3443 | ||
3444 | /* Only process profitable increments. Nothing useful can be done | |
3445 | to a cast or copy. */ | |
7bf55a70 BS |
3446 | if (i >= 0 |
3447 | && profitable_increment_p (i) | |
88ca9ea1 | 3448 | && orig_code != MODIFY_EXPR |
d822570f | 3449 | && !CONVERT_EXPR_CODE_P (orig_code)) |
88ca9ea1 | 3450 | { |
9b92d12b BS |
3451 | if (phi_dependent_cand_p (c)) |
3452 | { | |
355fe088 | 3453 | gimple *phi = lookup_cand (c->def_phi)->cand_stmt; |
9b92d12b BS |
3454 | |
3455 | if (all_phi_incrs_profitable (c, phi)) | |
3456 | { | |
3457 | /* Look up the LHS SSA name from C's basis. This will be | |
3458 | the RHS1 of the adds we will introduce to create new | |
3459 | phi arguments. */ | |
3460 | slsr_cand_t basis = lookup_cand (c->basis); | |
3461 | tree basis_name = gimple_assign_lhs (basis->cand_stmt); | |
3462 | ||
3463 | /* Create a new phi statement that will represent C's true | |
3464 | basis after the transformation is complete. */ | |
3465 | location_t loc = gimple_location (c->cand_stmt); | |
3466 | tree name = create_phi_basis (c, phi, basis_name, | |
3467 | loc, UNKNOWN_STRIDE); | |
3468 | ||
3469 | /* Replace C with an add of the new basis phi and the | |
3470 | increment. */ | |
a7a7d10e | 3471 | replace_one_candidate (c, i, name); |
9b92d12b BS |
3472 | } |
3473 | } | |
3474 | else | |
3475 | { | |
3476 | slsr_cand_t basis = lookup_cand (c->basis); | |
3477 | tree basis_name = gimple_assign_lhs (basis->cand_stmt); | |
a7a7d10e | 3478 | replace_one_candidate (c, i, basis_name); |
9b92d12b | 3479 | } |
88ca9ea1 BS |
3480 | } |
3481 | } | |
3482 | ||
3483 | if (c->sibling) | |
3484 | replace_profitable_candidates (lookup_cand (c->sibling)); | |
3485 | ||
3486 | if (c->dependent) | |
3487 | replace_profitable_candidates (lookup_cand (c->dependent)); | |
3488 | } | |
3489 | \f | |
f9453c07 BS |
3490 | /* Analyze costs of related candidates in the candidate vector, |
3491 | and make beneficial replacements. */ | |
3492 | ||
3493 | static void | |
3494 | analyze_candidates_and_replace (void) | |
3495 | { | |
3496 | unsigned i; | |
3497 | slsr_cand_t c; | |
3498 | ||
3499 | /* Each candidate that has a null basis and a non-null | |
3500 | dependent is the root of a tree of related statements. | |
3501 | Analyze each tree to determine a subset of those | |
3502 | statements that can be replaced with maximum benefit. */ | |
9771b263 | 3503 | FOR_EACH_VEC_ELT (cand_vec, i, c) |
f9453c07 BS |
3504 | { |
3505 | slsr_cand_t first_dep; | |
3506 | ||
3507 | if (c->basis != 0 || c->dependent == 0) | |
3508 | continue; | |
3509 | ||
3510 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3511 | fprintf (dump_file, "\nProcessing dependency tree rooted at %d.\n", | |
3512 | c->cand_num); | |
3513 | ||
3514 | first_dep = lookup_cand (c->dependent); | |
3515 | ||
2749c8f6 BS |
3516 | /* If this is a chain of CAND_REFs, unconditionally replace |
3517 | each of them with a strength-reduced data reference. */ | |
3518 | if (c->kind == CAND_REF) | |
3519 | replace_refs (c); | |
3520 | ||
9b92d12b BS |
3521 | /* If the common stride of all related candidates is a known |
3522 | constant, each candidate without a phi-dependence can be | |
3523 | profitably replaced. Each replaces a multiply by a single | |
3524 | add, with the possibility that a feeding add also goes dead. | |
3525 | A candidate with a phi-dependence is replaced only if the | |
3526 | compensation code it requires is offset by the strength | |
3527 | reduction savings. */ | |
3528 | else if (TREE_CODE (c->stride) == INTEGER_CST) | |
3529 | replace_uncond_cands_and_profitable_phis (first_dep); | |
f9453c07 | 3530 | |
88ca9ea1 BS |
3531 | /* When the stride is an SSA name, it may still be profitable |
3532 | to replace some or all of the dependent candidates, depending | |
3533 | on whether the introduced increments can be reused, or are | |
3534 | less expensive to calculate than the replaced statements. */ | |
3535 | else | |
3536 | { | |
ef4bddc2 | 3537 | machine_mode mode; |
88ca9ea1 BS |
3538 | bool speed; |
3539 | ||
3540 | /* Determine whether we'll be generating pointer arithmetic | |
3541 | when replacing candidates. */ | |
3542 | address_arithmetic_p = (c->kind == CAND_ADD | |
99cababb | 3543 | && POINTER_TYPE_P (c->cand_type)); |
88ca9ea1 BS |
3544 | |
3545 | /* If all candidates have already been replaced under other | |
3546 | interpretations, nothing remains to be done. */ | |
4b847da9 | 3547 | if (!count_candidates (c)) |
88ca9ea1 BS |
3548 | continue; |
3549 | ||
3550 | /* Construct an array of increments for this candidate chain. */ | |
4b847da9 | 3551 | incr_vec = XNEWVEC (incr_info, MAX_INCR_VEC_LEN); |
88ca9ea1 BS |
3552 | incr_vec_len = 0; |
3553 | record_increments (c); | |
3554 | ||
3555 | /* Determine which increments are profitable to replace. */ | |
3556 | mode = TYPE_MODE (TREE_TYPE (gimple_assign_lhs (c->cand_stmt))); | |
3557 | speed = optimize_cands_for_speed_p (c); | |
3558 | analyze_increments (first_dep, mode, speed); | |
3559 | ||
3560 | /* Insert initializers of the form T_0 = stride * increment | |
3561 | for use in profitable replacements. */ | |
3562 | insert_initializers (first_dep); | |
3563 | dump_incr_vec (); | |
3564 | ||
3565 | /* Perform the replacements. */ | |
3566 | replace_profitable_candidates (first_dep); | |
3567 | free (incr_vec); | |
3568 | } | |
f9453c07 BS |
3569 | } |
3570 | } | |
3571 | ||
17795822 TS |
3572 | namespace { |
3573 | ||
3574 | const pass_data pass_data_strength_reduction = | |
be55bfe6 TS |
3575 | { |
3576 | GIMPLE_PASS, /* type */ | |
3577 | "slsr", /* name */ | |
3578 | OPTGROUP_NONE, /* optinfo_flags */ | |
be55bfe6 TS |
3579 | TV_GIMPLE_SLSR, /* tv_id */ |
3580 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
3581 | 0, /* properties_provided */ | |
3582 | 0, /* properties_destroyed */ | |
3583 | 0, /* todo_flags_start */ | |
3bea341f | 3584 | 0, /* todo_flags_finish */ |
be55bfe6 TS |
3585 | }; |
3586 | ||
17795822 | 3587 | class pass_strength_reduction : public gimple_opt_pass |
be55bfe6 TS |
3588 | { |
3589 | public: | |
3590 | pass_strength_reduction (gcc::context *ctxt) | |
3591 | : gimple_opt_pass (pass_data_strength_reduction, ctxt) | |
3592 | {} | |
3593 | ||
3594 | /* opt_pass methods: */ | |
3595 | virtual bool gate (function *) { return flag_tree_slsr; } | |
3596 | virtual unsigned int execute (function *); | |
3597 | ||
3598 | }; // class pass_strength_reduction | |
3599 | ||
3600 | unsigned | |
3601 | pass_strength_reduction::execute (function *fun) | |
f9453c07 | 3602 | { |
f9453c07 BS |
3603 | /* Create the obstack where candidates will reside. */ |
3604 | gcc_obstack_init (&cand_obstack); | |
3605 | ||
3606 | /* Allocate the candidate vector. */ | |
9771b263 | 3607 | cand_vec.create (128); |
f9453c07 BS |
3608 | |
3609 | /* Allocate the mapping from statements to candidate indices. */ | |
355fe088 | 3610 | stmt_cand_map = new hash_map<gimple *, slsr_cand_t>; |
f9453c07 BS |
3611 | |
3612 | /* Create the obstack where candidate chains will reside. */ | |
3613 | gcc_obstack_init (&chain_obstack); | |
3614 | ||
3cfd4469 | 3615 | /* Allocate the mapping from base expressions to candidate chains. */ |
c203e8a7 | 3616 | base_cand_map = new hash_table<cand_chain_hasher> (500); |
f9453c07 | 3617 | |
96d75a2c | 3618 | /* Allocate the mapping from bases to alternative bases. */ |
b787e7a2 | 3619 | alt_base_map = new hash_map<tree, tree>; |
96d75a2c | 3620 | |
f9453c07 BS |
3621 | /* Initialize the loop optimizer. We need to detect flow across |
3622 | back edges, and this gives us dominator information as well. */ | |
3623 | loop_optimizer_init (AVOID_CFG_MODIFICATIONS); | |
3624 | ||
f9453c07 BS |
3625 | /* Walk the CFG in predominator order looking for strength reduction |
3626 | candidates. */ | |
4d9192b5 | 3627 | find_candidates_dom_walker (CDI_DOMINATORS) |
be55bfe6 | 3628 | .walk (fun->cfg->x_entry_block_ptr); |
f9453c07 BS |
3629 | |
3630 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3631 | { | |
3632 | dump_cand_vec (); | |
3633 | dump_cand_chains (); | |
3634 | } | |
3635 | ||
b787e7a2 | 3636 | delete alt_base_map; |
96d75a2c YZ |
3637 | free_affine_expand_cache (&name_expansions); |
3638 | ||
f9453c07 BS |
3639 | /* Analyze costs and make appropriate replacements. */ |
3640 | analyze_candidates_and_replace (); | |
3641 | ||
f9453c07 | 3642 | loop_optimizer_finalize (); |
c203e8a7 TS |
3643 | delete base_cand_map; |
3644 | base_cand_map = NULL; | |
f9453c07 | 3645 | obstack_free (&chain_obstack, NULL); |
b787e7a2 | 3646 | delete stmt_cand_map; |
9771b263 | 3647 | cand_vec.release (); |
f9453c07 | 3648 | obstack_free (&cand_obstack, NULL); |
f9453c07 BS |
3649 | |
3650 | return 0; | |
3651 | } | |
3652 | ||
17795822 TS |
3653 | } // anon namespace |
3654 | ||
27a4cd48 DM |
3655 | gimple_opt_pass * |
3656 | make_pass_strength_reduction (gcc::context *ctxt) | |
3657 | { | |
3658 | return new pass_strength_reduction (ctxt); | |
3659 | } |