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f9453c07 | 1 | /* Straight-line strength reduction. |
5624e564 | 2 | Copyright (C) 2012-2015 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 | } | |
788 | else | |
789 | { | |
790 | derived_base_name = arg; | |
791 | ||
792 | if (SSA_NAME_IS_DEFAULT_DEF (arg)) | |
fefa31b5 | 793 | arg_bb = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
9b92d12b BS |
794 | else |
795 | gimple_bb (SSA_NAME_DEF_STMT (arg)); | |
796 | } | |
797 | ||
798 | if (!arg_bb || arg_bb->loop_father != cand_loop) | |
799 | return; | |
800 | ||
801 | if (i == 0) | |
802 | arg0_base = derived_base_name; | |
803 | else if (!operand_equal_p (derived_base_name, arg0_base, 0)) | |
804 | return; | |
805 | } | |
806 | ||
807 | /* Create the candidate. "alloc_cand_and_find_basis" is named | |
808 | misleadingly for this case, as no basis will be sought for a | |
809 | CAND_PHI. */ | |
810 | base_type = TREE_TYPE (arg0_base); | |
811 | ||
807e902e KZ |
812 | c = alloc_cand_and_find_basis (CAND_PHI, phi, arg0_base, |
813 | 0, integer_one_node, base_type, savings); | |
9b92d12b BS |
814 | |
815 | /* Add the candidate to the statement-candidate mapping. */ | |
816 | add_cand_for_stmt (phi, c); | |
817 | } | |
818 | ||
c068654b BC |
819 | /* Given PBASE which is a pointer to tree, look up the defining |
820 | statement for it and check whether the candidate is in the | |
821 | form of: | |
822 | ||
823 | X = B + (1 * S), S is integer constant | |
824 | X = B + (i * S), S is integer one | |
825 | ||
826 | If so, set PBASE to the candidate's base_expr and return double | |
827 | int (i * S). | |
828 | Otherwise, just return double int zero. */ | |
829 | ||
807e902e | 830 | static widest_int |
c068654b BC |
831 | backtrace_base_for_ref (tree *pbase) |
832 | { | |
833 | tree base_in = *pbase; | |
834 | slsr_cand_t base_cand; | |
835 | ||
836 | STRIP_NOPS (base_in); | |
0916f876 YZ |
837 | |
838 | /* Strip off widening conversion(s) to handle cases where | |
839 | e.g. 'B' is widened from an 'int' in order to calculate | |
840 | a 64-bit address. */ | |
841 | if (CONVERT_EXPR_P (base_in) | |
842 | && legal_cast_p_1 (base_in, TREE_OPERAND (base_in, 0))) | |
843 | base_in = get_unwidened (base_in, NULL_TREE); | |
844 | ||
c068654b | 845 | if (TREE_CODE (base_in) != SSA_NAME) |
807e902e | 846 | return 0; |
c068654b BC |
847 | |
848 | base_cand = base_cand_from_table (base_in); | |
849 | ||
850 | while (base_cand && base_cand->kind != CAND_PHI) | |
851 | { | |
852 | if (base_cand->kind == CAND_ADD | |
807e902e | 853 | && base_cand->index == 1 |
c068654b BC |
854 | && TREE_CODE (base_cand->stride) == INTEGER_CST) |
855 | { | |
856 | /* X = B + (1 * S), S is integer constant. */ | |
857 | *pbase = base_cand->base_expr; | |
807e902e | 858 | return wi::to_widest (base_cand->stride); |
c068654b BC |
859 | } |
860 | else if (base_cand->kind == CAND_ADD | |
861 | && TREE_CODE (base_cand->stride) == INTEGER_CST | |
862 | && integer_onep (base_cand->stride)) | |
1d2151c6 | 863 | { |
c068654b BC |
864 | /* X = B + (i * S), S is integer one. */ |
865 | *pbase = base_cand->base_expr; | |
866 | return base_cand->index; | |
867 | } | |
868 | ||
869 | if (base_cand->next_interp) | |
870 | base_cand = lookup_cand (base_cand->next_interp); | |
871 | else | |
872 | base_cand = NULL; | |
873 | } | |
874 | ||
807e902e | 875 | return 0; |
c068654b BC |
876 | } |
877 | ||
2749c8f6 BS |
878 | /* Look for the following pattern: |
879 | ||
880 | *PBASE: MEM_REF (T1, C1) | |
881 | ||
882 | *POFFSET: MULT_EXPR (T2, C3) [C2 is zero] | |
883 | or | |
884 | MULT_EXPR (PLUS_EXPR (T2, C2), C3) | |
885 | or | |
886 | MULT_EXPR (MINUS_EXPR (T2, -C2), C3) | |
887 | ||
888 | *PINDEX: C4 * BITS_PER_UNIT | |
889 | ||
890 | If not present, leave the input values unchanged and return FALSE. | |
891 | Otherwise, modify the input values as follows and return TRUE: | |
892 | ||
893 | *PBASE: T1 | |
894 | *POFFSET: MULT_EXPR (T2, C3) | |
c068654b BC |
895 | *PINDEX: C1 + (C2 * C3) + C4 |
896 | ||
897 | When T2 is recorded by a CAND_ADD in the form of (T2' + C5), it | |
898 | will be further restructured to: | |
899 | ||
900 | *PBASE: T1 | |
901 | *POFFSET: MULT_EXPR (T2', C3) | |
902 | *PINDEX: C1 + (C2 * C3) + C4 + (C5 * C3) */ | |
2749c8f6 BS |
903 | |
904 | static bool | |
807e902e | 905 | restructure_reference (tree *pbase, tree *poffset, widest_int *pindex, |
2749c8f6 BS |
906 | tree *ptype) |
907 | { | |
908 | tree base = *pbase, offset = *poffset; | |
807e902e KZ |
909 | widest_int index = *pindex; |
910 | tree mult_op0, t1, t2, type; | |
911 | widest_int c1, c2, c3, c4, c5; | |
2749c8f6 BS |
912 | |
913 | if (!base | |
914 | || !offset | |
915 | || TREE_CODE (base) != MEM_REF | |
916 | || TREE_CODE (offset) != MULT_EXPR | |
917 | || TREE_CODE (TREE_OPERAND (offset, 1)) != INTEGER_CST | |
807e902e | 918 | || wi::umod_floor (index, BITS_PER_UNIT) != 0) |
2749c8f6 BS |
919 | return false; |
920 | ||
921 | t1 = TREE_OPERAND (base, 0); | |
807e902e | 922 | c1 = widest_int::from (mem_ref_offset (base), SIGNED); |
2749c8f6 BS |
923 | type = TREE_TYPE (TREE_OPERAND (base, 1)); |
924 | ||
925 | mult_op0 = TREE_OPERAND (offset, 0); | |
807e902e | 926 | c3 = wi::to_widest (TREE_OPERAND (offset, 1)); |
2749c8f6 BS |
927 | |
928 | if (TREE_CODE (mult_op0) == PLUS_EXPR) | |
929 | ||
930 | if (TREE_CODE (TREE_OPERAND (mult_op0, 1)) == INTEGER_CST) | |
931 | { | |
932 | t2 = TREE_OPERAND (mult_op0, 0); | |
807e902e | 933 | c2 = wi::to_widest (TREE_OPERAND (mult_op0, 1)); |
2749c8f6 BS |
934 | } |
935 | else | |
936 | return false; | |
937 | ||
938 | else if (TREE_CODE (mult_op0) == MINUS_EXPR) | |
939 | ||
940 | if (TREE_CODE (TREE_OPERAND (mult_op0, 1)) == INTEGER_CST) | |
941 | { | |
942 | t2 = TREE_OPERAND (mult_op0, 0); | |
807e902e | 943 | c2 = -wi::to_widest (TREE_OPERAND (mult_op0, 1)); |
2749c8f6 BS |
944 | } |
945 | else | |
946 | return false; | |
947 | ||
948 | else | |
949 | { | |
950 | t2 = mult_op0; | |
807e902e | 951 | c2 = 0; |
2749c8f6 BS |
952 | } |
953 | ||
807e902e | 954 | c4 = wi::lrshift (index, LOG2_BITS_PER_UNIT); |
c068654b | 955 | c5 = backtrace_base_for_ref (&t2); |
2749c8f6 BS |
956 | |
957 | *pbase = t1; | |
c068654b | 958 | *poffset = fold_build2 (MULT_EXPR, sizetype, fold_convert (sizetype, t2), |
807e902e | 959 | wide_int_to_tree (sizetype, c3)); |
c068654b | 960 | *pindex = c1 + c2 * c3 + c4 + c5 * c3; |
2749c8f6 BS |
961 | *ptype = type; |
962 | ||
963 | return true; | |
964 | } | |
965 | ||
966 | /* Given GS which contains a data reference, create a CAND_REF entry in | |
967 | the candidate table and attempt to find a basis. */ | |
968 | ||
969 | static void | |
355fe088 | 970 | slsr_process_ref (gimple *gs) |
2749c8f6 BS |
971 | { |
972 | tree ref_expr, base, offset, type; | |
973 | HOST_WIDE_INT bitsize, bitpos; | |
ef4bddc2 | 974 | machine_mode mode; |
ee45a32d | 975 | int unsignedp, reversep, volatilep; |
2749c8f6 BS |
976 | slsr_cand_t c; |
977 | ||
978 | if (gimple_vdef (gs)) | |
979 | ref_expr = gimple_assign_lhs (gs); | |
980 | else | |
981 | ref_expr = gimple_assign_rhs1 (gs); | |
982 | ||
983 | if (!handled_component_p (ref_expr) | |
984 | || TREE_CODE (ref_expr) == BIT_FIELD_REF | |
985 | || (TREE_CODE (ref_expr) == COMPONENT_REF | |
986 | && DECL_BIT_FIELD (TREE_OPERAND (ref_expr, 1)))) | |
987 | return; | |
988 | ||
989 | base = get_inner_reference (ref_expr, &bitsize, &bitpos, &offset, &mode, | |
ee45a32d EB |
990 | &unsignedp, &reversep, &volatilep, false); |
991 | if (reversep) | |
992 | return; | |
807e902e | 993 | widest_int index = bitpos; |
2749c8f6 BS |
994 | |
995 | if (!restructure_reference (&base, &offset, &index, &type)) | |
996 | return; | |
997 | ||
998 | c = alloc_cand_and_find_basis (CAND_REF, gs, base, index, offset, | |
999 | type, 0); | |
1000 | ||
1001 | /* Add the candidate to the statement-candidate mapping. */ | |
1002 | add_cand_for_stmt (gs, c); | |
1003 | } | |
1004 | ||
f9453c07 BS |
1005 | /* Create a candidate entry for a statement GS, where GS multiplies |
1006 | two SSA names BASE_IN and STRIDE_IN. Propagate any known information | |
1007 | about the two SSA names into the new candidate. Return the new | |
1008 | candidate. */ | |
1009 | ||
1010 | static slsr_cand_t | |
355fe088 | 1011 | create_mul_ssa_cand (gimple *gs, tree base_in, tree stride_in, bool speed) |
f9453c07 BS |
1012 | { |
1013 | tree base = NULL_TREE, stride = NULL_TREE, ctype = NULL_TREE; | |
807e902e | 1014 | widest_int index; |
f9453c07 BS |
1015 | unsigned savings = 0; |
1016 | slsr_cand_t c; | |
1017 | slsr_cand_t base_cand = base_cand_from_table (base_in); | |
1018 | ||
1019 | /* Look at all interpretations of the base candidate, if necessary, | |
1020 | to find information to propagate into this candidate. */ | |
9b92d12b | 1021 | while (base_cand && !base && base_cand->kind != CAND_PHI) |
f9453c07 BS |
1022 | { |
1023 | ||
9b92d12b | 1024 | if (base_cand->kind == CAND_MULT && integer_onep (base_cand->stride)) |
f9453c07 BS |
1025 | { |
1026 | /* Y = (B + i') * 1 | |
1027 | X = Y * Z | |
1028 | ================ | |
1029 | X = (B + i') * Z */ | |
3cfd4469 | 1030 | base = base_cand->base_expr; |
f9453c07 BS |
1031 | index = base_cand->index; |
1032 | stride = stride_in; | |
1033 | ctype = base_cand->cand_type; | |
1034 | if (has_single_use (base_in)) | |
1035 | savings = (base_cand->dead_savings | |
1036 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1037 | } | |
1038 | else if (base_cand->kind == CAND_ADD | |
1039 | && TREE_CODE (base_cand->stride) == INTEGER_CST) | |
1040 | { | |
1041 | /* Y = B + (i' * S), S constant | |
1042 | X = Y * Z | |
1043 | ============================ | |
1044 | X = B + ((i' * S) * Z) */ | |
3cfd4469 | 1045 | base = base_cand->base_expr; |
807e902e | 1046 | index = base_cand->index * wi::to_widest (base_cand->stride); |
f9453c07 BS |
1047 | stride = stride_in; |
1048 | ctype = base_cand->cand_type; | |
1049 | if (has_single_use (base_in)) | |
1050 | savings = (base_cand->dead_savings | |
1051 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1052 | } | |
1053 | ||
1054 | if (base_cand->next_interp) | |
1055 | base_cand = lookup_cand (base_cand->next_interp); | |
1056 | else | |
1057 | base_cand = NULL; | |
1058 | } | |
1059 | ||
1060 | if (!base) | |
1061 | { | |
1062 | /* No interpretations had anything useful to propagate, so | |
1063 | produce X = (Y + 0) * Z. */ | |
1064 | base = base_in; | |
807e902e | 1065 | index = 0; |
f9453c07 | 1066 | stride = stride_in; |
b2ec94d4 | 1067 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1068 | } |
1069 | ||
1070 | c = alloc_cand_and_find_basis (CAND_MULT, gs, base, index, stride, | |
1071 | ctype, savings); | |
1072 | return c; | |
1073 | } | |
1074 | ||
1075 | /* Create a candidate entry for a statement GS, where GS multiplies | |
1076 | SSA name BASE_IN by constant STRIDE_IN. Propagate any known | |
1077 | information about BASE_IN into the new candidate. Return the new | |
1078 | candidate. */ | |
1079 | ||
1080 | static slsr_cand_t | |
355fe088 | 1081 | create_mul_imm_cand (gimple *gs, tree base_in, tree stride_in, bool speed) |
f9453c07 BS |
1082 | { |
1083 | tree base = NULL_TREE, stride = NULL_TREE, ctype = NULL_TREE; | |
807e902e | 1084 | widest_int index, temp; |
f9453c07 BS |
1085 | unsigned savings = 0; |
1086 | slsr_cand_t c; | |
1087 | slsr_cand_t base_cand = base_cand_from_table (base_in); | |
1088 | ||
1089 | /* Look at all interpretations of the base candidate, if necessary, | |
1090 | to find information to propagate into this candidate. */ | |
9b92d12b | 1091 | while (base_cand && !base && base_cand->kind != CAND_PHI) |
f9453c07 BS |
1092 | { |
1093 | if (base_cand->kind == CAND_MULT | |
1094 | && TREE_CODE (base_cand->stride) == INTEGER_CST) | |
1095 | { | |
1096 | /* Y = (B + i') * S, S constant | |
1097 | X = Y * c | |
1098 | ============================ | |
1099 | X = (B + i') * (S * c) */ | |
807e902e KZ |
1100 | temp = wi::to_widest (base_cand->stride) * wi::to_widest (stride_in); |
1101 | if (wi::fits_to_tree_p (temp, TREE_TYPE (stride_in))) | |
61ba7329 BS |
1102 | { |
1103 | base = base_cand->base_expr; | |
1104 | index = base_cand->index; | |
807e902e | 1105 | stride = wide_int_to_tree (TREE_TYPE (stride_in), temp); |
61ba7329 BS |
1106 | ctype = base_cand->cand_type; |
1107 | if (has_single_use (base_in)) | |
1108 | savings = (base_cand->dead_savings | |
1109 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1110 | } | |
f9453c07 | 1111 | } |
9b92d12b | 1112 | else if (base_cand->kind == CAND_ADD && integer_onep (base_cand->stride)) |
f9453c07 BS |
1113 | { |
1114 | /* Y = B + (i' * 1) | |
1115 | X = Y * c | |
1116 | =========================== | |
1117 | X = (B + i') * c */ | |
3cfd4469 | 1118 | base = base_cand->base_expr; |
f9453c07 BS |
1119 | index = base_cand->index; |
1120 | stride = stride_in; | |
1121 | ctype = base_cand->cand_type; | |
1122 | if (has_single_use (base_in)) | |
1123 | savings = (base_cand->dead_savings | |
1124 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1125 | } | |
1126 | else if (base_cand->kind == CAND_ADD | |
807e902e | 1127 | && base_cand->index == 1 |
f9453c07 BS |
1128 | && TREE_CODE (base_cand->stride) == INTEGER_CST) |
1129 | { | |
1130 | /* Y = B + (1 * S), S constant | |
1131 | X = Y * c | |
1132 | =========================== | |
1133 | X = (B + S) * c */ | |
3cfd4469 | 1134 | base = base_cand->base_expr; |
807e902e | 1135 | index = wi::to_widest (base_cand->stride); |
f9453c07 BS |
1136 | stride = stride_in; |
1137 | ctype = base_cand->cand_type; | |
1138 | if (has_single_use (base_in)) | |
1139 | savings = (base_cand->dead_savings | |
1140 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1141 | } | |
1142 | ||
1143 | if (base_cand->next_interp) | |
1144 | base_cand = lookup_cand (base_cand->next_interp); | |
1145 | else | |
1146 | base_cand = NULL; | |
1147 | } | |
1148 | ||
1149 | if (!base) | |
1150 | { | |
1151 | /* No interpretations had anything useful to propagate, so | |
1152 | produce X = (Y + 0) * c. */ | |
1153 | base = base_in; | |
807e902e | 1154 | index = 0; |
f9453c07 | 1155 | stride = stride_in; |
b2ec94d4 | 1156 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1157 | } |
1158 | ||
1159 | c = alloc_cand_and_find_basis (CAND_MULT, gs, base, index, stride, | |
1160 | ctype, savings); | |
1161 | return c; | |
1162 | } | |
1163 | ||
1164 | /* Given GS which is a multiply of scalar integers, make an appropriate | |
1165 | entry in the candidate table. If this is a multiply of two SSA names, | |
1166 | create two CAND_MULT interpretations and attempt to find a basis for | |
1167 | each of them. Otherwise, create a single CAND_MULT and attempt to | |
1168 | find a basis. */ | |
1169 | ||
1170 | static void | |
355fe088 | 1171 | slsr_process_mul (gimple *gs, tree rhs1, tree rhs2, bool speed) |
f9453c07 BS |
1172 | { |
1173 | slsr_cand_t c, c2; | |
1174 | ||
1175 | /* If this is a multiply of an SSA name with itself, it is highly | |
1176 | unlikely that we will get a strength reduction opportunity, so | |
1177 | don't record it as a candidate. This simplifies the logic for | |
1178 | finding a basis, so if this is removed that must be considered. */ | |
1179 | if (rhs1 == rhs2) | |
1180 | return; | |
1181 | ||
1182 | if (TREE_CODE (rhs2) == SSA_NAME) | |
1183 | { | |
1184 | /* Record an interpretation of this statement in the candidate table | |
3cfd4469 | 1185 | assuming RHS1 is the base expression and RHS2 is the stride. */ |
f9453c07 BS |
1186 | c = create_mul_ssa_cand (gs, rhs1, rhs2, speed); |
1187 | ||
1188 | /* Add the first interpretation to the statement-candidate mapping. */ | |
1189 | add_cand_for_stmt (gs, c); | |
1190 | ||
1191 | /* Record another interpretation of this statement assuming RHS1 | |
3cfd4469 | 1192 | is the stride and RHS2 is the base expression. */ |
f9453c07 BS |
1193 | c2 = create_mul_ssa_cand (gs, rhs2, rhs1, speed); |
1194 | c->next_interp = c2->cand_num; | |
1195 | } | |
1196 | else | |
1197 | { | |
1198 | /* Record an interpretation for the multiply-immediate. */ | |
1199 | c = create_mul_imm_cand (gs, rhs1, rhs2, speed); | |
1200 | ||
1201 | /* Add the interpretation to the statement-candidate mapping. */ | |
1202 | add_cand_for_stmt (gs, c); | |
1203 | } | |
1204 | } | |
1205 | ||
1206 | /* Create a candidate entry for a statement GS, where GS adds two | |
1207 | SSA names BASE_IN and ADDEND_IN if SUBTRACT_P is false, and | |
1208 | subtracts ADDEND_IN from BASE_IN otherwise. Propagate any known | |
1209 | information about the two SSA names into the new candidate. | |
1210 | Return the new candidate. */ | |
1211 | ||
1212 | static slsr_cand_t | |
355fe088 | 1213 | create_add_ssa_cand (gimple *gs, tree base_in, tree addend_in, |
f9453c07 BS |
1214 | bool subtract_p, bool speed) |
1215 | { | |
1216 | tree base = NULL_TREE, stride = NULL_TREE, ctype = NULL; | |
807e902e | 1217 | widest_int index; |
f9453c07 BS |
1218 | unsigned savings = 0; |
1219 | slsr_cand_t c; | |
1220 | slsr_cand_t base_cand = base_cand_from_table (base_in); | |
1221 | slsr_cand_t addend_cand = base_cand_from_table (addend_in); | |
1222 | ||
1223 | /* The most useful transformation is a multiply-immediate feeding | |
1224 | an add or subtract. Look for that first. */ | |
9b92d12b | 1225 | while (addend_cand && !base && addend_cand->kind != CAND_PHI) |
f9453c07 BS |
1226 | { |
1227 | if (addend_cand->kind == CAND_MULT | |
807e902e | 1228 | && addend_cand->index == 0 |
f9453c07 BS |
1229 | && TREE_CODE (addend_cand->stride) == INTEGER_CST) |
1230 | { | |
1231 | /* Z = (B + 0) * S, S constant | |
1232 | X = Y +/- Z | |
1233 | =========================== | |
1234 | X = Y + ((+/-1 * S) * B) */ | |
1235 | base = base_in; | |
807e902e | 1236 | index = wi::to_widest (addend_cand->stride); |
f9453c07 | 1237 | if (subtract_p) |
27bcd47c | 1238 | index = -index; |
3cfd4469 | 1239 | stride = addend_cand->base_expr; |
b2ec94d4 | 1240 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1241 | if (has_single_use (addend_in)) |
1242 | savings = (addend_cand->dead_savings | |
1243 | + stmt_cost (addend_cand->cand_stmt, speed)); | |
1244 | } | |
1245 | ||
1246 | if (addend_cand->next_interp) | |
1247 | addend_cand = lookup_cand (addend_cand->next_interp); | |
1248 | else | |
1249 | addend_cand = NULL; | |
1250 | } | |
1251 | ||
9b92d12b | 1252 | while (base_cand && !base && base_cand->kind != CAND_PHI) |
f9453c07 BS |
1253 | { |
1254 | if (base_cand->kind == CAND_ADD | |
807e902e | 1255 | && (base_cand->index == 0 |
f9453c07 BS |
1256 | || operand_equal_p (base_cand->stride, |
1257 | integer_zero_node, 0))) | |
1258 | { | |
1259 | /* Y = B + (i' * S), i' * S = 0 | |
1260 | X = Y +/- Z | |
1261 | ============================ | |
1262 | X = B + (+/-1 * Z) */ | |
3cfd4469 | 1263 | base = base_cand->base_expr; |
807e902e | 1264 | index = subtract_p ? -1 : 1; |
f9453c07 BS |
1265 | stride = addend_in; |
1266 | ctype = base_cand->cand_type; | |
1267 | if (has_single_use (base_in)) | |
1268 | savings = (base_cand->dead_savings | |
1269 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1270 | } | |
1271 | else if (subtract_p) | |
1272 | { | |
1273 | slsr_cand_t subtrahend_cand = base_cand_from_table (addend_in); | |
1274 | ||
9b92d12b | 1275 | while (subtrahend_cand && !base && subtrahend_cand->kind != CAND_PHI) |
f9453c07 BS |
1276 | { |
1277 | if (subtrahend_cand->kind == CAND_MULT | |
807e902e | 1278 | && subtrahend_cand->index == 0 |
f9453c07 BS |
1279 | && TREE_CODE (subtrahend_cand->stride) == INTEGER_CST) |
1280 | { | |
1281 | /* Z = (B + 0) * S, S constant | |
1282 | X = Y - Z | |
1283 | =========================== | |
1284 | Value: X = Y + ((-1 * S) * B) */ | |
1285 | base = base_in; | |
807e902e | 1286 | index = wi::to_widest (subtrahend_cand->stride); |
27bcd47c | 1287 | index = -index; |
3cfd4469 | 1288 | stride = subtrahend_cand->base_expr; |
b2ec94d4 | 1289 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1290 | if (has_single_use (addend_in)) |
1291 | savings = (subtrahend_cand->dead_savings | |
1292 | + stmt_cost (subtrahend_cand->cand_stmt, speed)); | |
1293 | } | |
1294 | ||
1295 | if (subtrahend_cand->next_interp) | |
1296 | subtrahend_cand = lookup_cand (subtrahend_cand->next_interp); | |
1297 | else | |
1298 | subtrahend_cand = NULL; | |
1299 | } | |
1300 | } | |
1301 | ||
1302 | if (base_cand->next_interp) | |
1303 | base_cand = lookup_cand (base_cand->next_interp); | |
1304 | else | |
1305 | base_cand = NULL; | |
1306 | } | |
1307 | ||
1308 | if (!base) | |
1309 | { | |
1310 | /* No interpretations had anything useful to propagate, so | |
1311 | produce X = Y + (1 * Z). */ | |
1312 | base = base_in; | |
807e902e | 1313 | index = subtract_p ? -1 : 1; |
f9453c07 | 1314 | stride = addend_in; |
b2ec94d4 | 1315 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1316 | } |
1317 | ||
1318 | c = alloc_cand_and_find_basis (CAND_ADD, gs, base, index, stride, | |
1319 | ctype, savings); | |
1320 | return c; | |
1321 | } | |
1322 | ||
1323 | /* Create a candidate entry for a statement GS, where GS adds SSA | |
1324 | name BASE_IN to constant INDEX_IN. Propagate any known information | |
1325 | about BASE_IN into the new candidate. Return the new candidate. */ | |
1326 | ||
1327 | static slsr_cand_t | |
355fe088 | 1328 | create_add_imm_cand (gimple *gs, tree base_in, const widest_int &index_in, |
807e902e | 1329 | bool speed) |
f9453c07 BS |
1330 | { |
1331 | enum cand_kind kind = CAND_ADD; | |
1332 | tree base = NULL_TREE, stride = NULL_TREE, ctype = NULL_TREE; | |
807e902e | 1333 | widest_int index, multiple; |
f9453c07 BS |
1334 | unsigned savings = 0; |
1335 | slsr_cand_t c; | |
1336 | slsr_cand_t base_cand = base_cand_from_table (base_in); | |
1337 | ||
9b92d12b | 1338 | while (base_cand && !base && base_cand->kind != CAND_PHI) |
f9453c07 | 1339 | { |
807e902e | 1340 | signop sign = TYPE_SIGN (TREE_TYPE (base_cand->stride)); |
f9453c07 BS |
1341 | |
1342 | if (TREE_CODE (base_cand->stride) == INTEGER_CST | |
807e902e KZ |
1343 | && wi::multiple_of_p (index_in, wi::to_widest (base_cand->stride), |
1344 | sign, &multiple)) | |
f9453c07 BS |
1345 | { |
1346 | /* Y = (B + i') * S, S constant, c = kS for some integer k | |
1347 | X = Y + c | |
1348 | ============================ | |
1349 | X = (B + (i'+ k)) * S | |
1350 | OR | |
1351 | Y = B + (i' * S), S constant, c = kS for some integer k | |
1352 | X = Y + c | |
1353 | ============================ | |
1354 | X = (B + (i'+ k)) * S */ | |
1355 | kind = base_cand->kind; | |
3cfd4469 | 1356 | base = base_cand->base_expr; |
27bcd47c | 1357 | index = base_cand->index + multiple; |
f9453c07 BS |
1358 | stride = base_cand->stride; |
1359 | ctype = base_cand->cand_type; | |
1360 | if (has_single_use (base_in)) | |
1361 | savings = (base_cand->dead_savings | |
1362 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1363 | } | |
1364 | ||
1365 | if (base_cand->next_interp) | |
1366 | base_cand = lookup_cand (base_cand->next_interp); | |
1367 | else | |
1368 | base_cand = NULL; | |
1369 | } | |
1370 | ||
1371 | if (!base) | |
1372 | { | |
1373 | /* No interpretations had anything useful to propagate, so | |
1374 | produce X = Y + (c * 1). */ | |
1375 | kind = CAND_ADD; | |
1376 | base = base_in; | |
1377 | index = index_in; | |
1378 | stride = integer_one_node; | |
b2ec94d4 | 1379 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1380 | } |
1381 | ||
1382 | c = alloc_cand_and_find_basis (kind, gs, base, index, stride, | |
1383 | ctype, savings); | |
1384 | return c; | |
1385 | } | |
1386 | ||
1387 | /* Given GS which is an add or subtract of scalar integers or pointers, | |
1388 | make at least one appropriate entry in the candidate table. */ | |
1389 | ||
1390 | static void | |
355fe088 | 1391 | slsr_process_add (gimple *gs, tree rhs1, tree rhs2, bool speed) |
f9453c07 BS |
1392 | { |
1393 | bool subtract_p = gimple_assign_rhs_code (gs) == MINUS_EXPR; | |
1394 | slsr_cand_t c = NULL, c2; | |
1395 | ||
1396 | if (TREE_CODE (rhs2) == SSA_NAME) | |
1397 | { | |
3cfd4469 | 1398 | /* First record an interpretation assuming RHS1 is the base expression |
f9453c07 BS |
1399 | and RHS2 is the stride. But it doesn't make sense for the |
1400 | stride to be a pointer, so don't record a candidate in that case. */ | |
b2ec94d4 | 1401 | if (!POINTER_TYPE_P (TREE_TYPE (rhs2))) |
f9453c07 BS |
1402 | { |
1403 | c = create_add_ssa_cand (gs, rhs1, rhs2, subtract_p, speed); | |
1404 | ||
1405 | /* Add the first interpretation to the statement-candidate | |
1406 | mapping. */ | |
1407 | add_cand_for_stmt (gs, c); | |
1408 | } | |
1409 | ||
1410 | /* If the two RHS operands are identical, or this is a subtract, | |
1411 | we're done. */ | |
1412 | if (operand_equal_p (rhs1, rhs2, 0) || subtract_p) | |
1413 | return; | |
1414 | ||
1415 | /* Otherwise, record another interpretation assuming RHS2 is the | |
3cfd4469 | 1416 | base expression and RHS1 is the stride, again provided that the |
f9453c07 | 1417 | stride is not a pointer. */ |
b2ec94d4 | 1418 | if (!POINTER_TYPE_P (TREE_TYPE (rhs1))) |
f9453c07 BS |
1419 | { |
1420 | c2 = create_add_ssa_cand (gs, rhs2, rhs1, false, speed); | |
1421 | if (c) | |
1422 | c->next_interp = c2->cand_num; | |
1423 | else | |
1424 | add_cand_for_stmt (gs, c2); | |
1425 | } | |
1426 | } | |
1427 | else | |
1428 | { | |
f9453c07 | 1429 | /* Record an interpretation for the add-immediate. */ |
807e902e | 1430 | widest_int index = wi::to_widest (rhs2); |
f9453c07 | 1431 | if (subtract_p) |
27bcd47c | 1432 | index = -index; |
f9453c07 BS |
1433 | |
1434 | c = create_add_imm_cand (gs, rhs1, index, speed); | |
1435 | ||
1436 | /* Add the interpretation to the statement-candidate mapping. */ | |
1437 | add_cand_for_stmt (gs, c); | |
1438 | } | |
1439 | } | |
1440 | ||
1441 | /* Given GS which is a negate of a scalar integer, make an appropriate | |
1442 | entry in the candidate table. A negate is equivalent to a multiply | |
1443 | by -1. */ | |
1444 | ||
1445 | static void | |
355fe088 | 1446 | slsr_process_neg (gimple *gs, tree rhs1, bool speed) |
f9453c07 BS |
1447 | { |
1448 | /* Record a CAND_MULT interpretation for the multiply by -1. */ | |
1449 | slsr_cand_t c = create_mul_imm_cand (gs, rhs1, integer_minus_one_node, speed); | |
1450 | ||
1451 | /* Add the interpretation to the statement-candidate mapping. */ | |
1452 | add_cand_for_stmt (gs, c); | |
1453 | } | |
1454 | ||
6b5eea61 BS |
1455 | /* Help function for legal_cast_p, operating on two trees. Checks |
1456 | whether it's allowable to cast from RHS to LHS. See legal_cast_p | |
1457 | for more details. */ | |
1458 | ||
1459 | static bool | |
1460 | legal_cast_p_1 (tree lhs, tree rhs) | |
1461 | { | |
1462 | tree lhs_type, rhs_type; | |
1463 | unsigned lhs_size, rhs_size; | |
1464 | bool lhs_wraps, rhs_wraps; | |
1465 | ||
1466 | lhs_type = TREE_TYPE (lhs); | |
1467 | rhs_type = TREE_TYPE (rhs); | |
1468 | lhs_size = TYPE_PRECISION (lhs_type); | |
1469 | rhs_size = TYPE_PRECISION (rhs_type); | |
20bd649a MP |
1470 | lhs_wraps = ANY_INTEGRAL_TYPE_P (lhs_type) && TYPE_OVERFLOW_WRAPS (lhs_type); |
1471 | rhs_wraps = ANY_INTEGRAL_TYPE_P (rhs_type) && TYPE_OVERFLOW_WRAPS (rhs_type); | |
6b5eea61 BS |
1472 | |
1473 | if (lhs_size < rhs_size | |
1474 | || (rhs_wraps && !lhs_wraps) | |
1475 | || (rhs_wraps && lhs_wraps && rhs_size != lhs_size)) | |
1476 | return false; | |
1477 | ||
1478 | return true; | |
1479 | } | |
1480 | ||
f9453c07 BS |
1481 | /* Return TRUE if GS is a statement that defines an SSA name from |
1482 | a conversion and is legal for us to combine with an add and multiply | |
1483 | in the candidate table. For example, suppose we have: | |
1484 | ||
1485 | A = B + i; | |
1486 | C = (type) A; | |
1487 | D = C * S; | |
1488 | ||
1489 | Without the type-cast, we would create a CAND_MULT for D with base B, | |
1490 | index i, and stride S. We want to record this candidate only if it | |
1491 | is equivalent to apply the type cast following the multiply: | |
1492 | ||
1493 | A = B + i; | |
1494 | E = A * S; | |
1495 | D = (type) E; | |
1496 | ||
1497 | We will record the type with the candidate for D. This allows us | |
1498 | to use a similar previous candidate as a basis. If we have earlier seen | |
1499 | ||
1500 | A' = B + i'; | |
1501 | C' = (type) A'; | |
1502 | D' = C' * S; | |
1503 | ||
1504 | we can replace D with | |
1505 | ||
1506 | D = D' + (i - i') * S; | |
1507 | ||
1508 | But if moving the type-cast would change semantics, we mustn't do this. | |
1509 | ||
1510 | This is legitimate for casts from a non-wrapping integral type to | |
1511 | any integral type of the same or larger size. It is not legitimate | |
1512 | to convert a wrapping type to a non-wrapping type, or to a wrapping | |
1513 | type of a different size. I.e., with a wrapping type, we must | |
1514 | assume that the addition B + i could wrap, in which case performing | |
1515 | the multiply before or after one of the "illegal" type casts will | |
1516 | have different semantics. */ | |
1517 | ||
1518 | static bool | |
355fe088 | 1519 | legal_cast_p (gimple *gs, tree rhs) |
f9453c07 | 1520 | { |
f9453c07 BS |
1521 | if (!is_gimple_assign (gs) |
1522 | || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (gs))) | |
1523 | return false; | |
1524 | ||
6b5eea61 | 1525 | return legal_cast_p_1 (gimple_assign_lhs (gs), rhs); |
f9453c07 BS |
1526 | } |
1527 | ||
1528 | /* Given GS which is a cast to a scalar integer type, determine whether | |
1529 | the cast is legal for strength reduction. If so, make at least one | |
1530 | appropriate entry in the candidate table. */ | |
1531 | ||
1532 | static void | |
355fe088 | 1533 | slsr_process_cast (gimple *gs, tree rhs1, bool speed) |
f9453c07 BS |
1534 | { |
1535 | tree lhs, ctype; | |
1536 | slsr_cand_t base_cand, c, c2; | |
1537 | unsigned savings = 0; | |
1538 | ||
1539 | if (!legal_cast_p (gs, rhs1)) | |
1540 | return; | |
1541 | ||
1542 | lhs = gimple_assign_lhs (gs); | |
1543 | base_cand = base_cand_from_table (rhs1); | |
1544 | ctype = TREE_TYPE (lhs); | |
1545 | ||
9b92d12b | 1546 | if (base_cand && base_cand->kind != CAND_PHI) |
f9453c07 BS |
1547 | { |
1548 | while (base_cand) | |
1549 | { | |
1550 | /* Propagate all data from the base candidate except the type, | |
1551 | which comes from the cast, and the base candidate's cast, | |
1552 | which is no longer applicable. */ | |
1553 | if (has_single_use (rhs1)) | |
1554 | savings = (base_cand->dead_savings | |
1555 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1556 | ||
1557 | c = alloc_cand_and_find_basis (base_cand->kind, gs, | |
3cfd4469 | 1558 | base_cand->base_expr, |
f9453c07 BS |
1559 | base_cand->index, base_cand->stride, |
1560 | ctype, savings); | |
1561 | if (base_cand->next_interp) | |
1562 | base_cand = lookup_cand (base_cand->next_interp); | |
1563 | else | |
1564 | base_cand = NULL; | |
1565 | } | |
1566 | } | |
1567 | else | |
1568 | { | |
1569 | /* If nothing is known about the RHS, create fresh CAND_ADD and | |
1570 | CAND_MULT interpretations: | |
1571 | ||
1572 | X = Y + (0 * 1) | |
1573 | X = (Y + 0) * 1 | |
1574 | ||
1575 | The first of these is somewhat arbitrary, but the choice of | |
1576 | 1 for the stride simplifies the logic for propagating casts | |
1577 | into their uses. */ | |
807e902e KZ |
1578 | c = alloc_cand_and_find_basis (CAND_ADD, gs, rhs1, |
1579 | 0, integer_one_node, ctype, 0); | |
1580 | c2 = alloc_cand_and_find_basis (CAND_MULT, gs, rhs1, | |
1581 | 0, integer_one_node, ctype, 0); | |
f9453c07 BS |
1582 | c->next_interp = c2->cand_num; |
1583 | } | |
1584 | ||
1585 | /* Add the first (or only) interpretation to the statement-candidate | |
1586 | mapping. */ | |
1587 | add_cand_for_stmt (gs, c); | |
1588 | } | |
1589 | ||
1590 | /* Given GS which is a copy of a scalar integer type, make at least one | |
1591 | appropriate entry in the candidate table. | |
1592 | ||
1593 | This interface is included for completeness, but is unnecessary | |
1594 | if this pass immediately follows a pass that performs copy | |
1595 | propagation, such as DOM. */ | |
1596 | ||
1597 | static void | |
355fe088 | 1598 | slsr_process_copy (gimple *gs, tree rhs1, bool speed) |
f9453c07 BS |
1599 | { |
1600 | slsr_cand_t base_cand, c, c2; | |
1601 | unsigned savings = 0; | |
1602 | ||
1603 | base_cand = base_cand_from_table (rhs1); | |
1604 | ||
9b92d12b | 1605 | if (base_cand && base_cand->kind != CAND_PHI) |
f9453c07 BS |
1606 | { |
1607 | while (base_cand) | |
1608 | { | |
1609 | /* Propagate all data from the base candidate. */ | |
1610 | if (has_single_use (rhs1)) | |
1611 | savings = (base_cand->dead_savings | |
1612 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1613 | ||
1614 | c = alloc_cand_and_find_basis (base_cand->kind, gs, | |
3cfd4469 | 1615 | base_cand->base_expr, |
f9453c07 BS |
1616 | base_cand->index, base_cand->stride, |
1617 | base_cand->cand_type, savings); | |
1618 | if (base_cand->next_interp) | |
1619 | base_cand = lookup_cand (base_cand->next_interp); | |
1620 | else | |
1621 | base_cand = NULL; | |
1622 | } | |
1623 | } | |
1624 | else | |
1625 | { | |
1626 | /* If nothing is known about the RHS, create fresh CAND_ADD and | |
1627 | CAND_MULT interpretations: | |
1628 | ||
1629 | X = Y + (0 * 1) | |
1630 | X = (Y + 0) * 1 | |
1631 | ||
1632 | The first of these is somewhat arbitrary, but the choice of | |
1633 | 1 for the stride simplifies the logic for propagating casts | |
1634 | into their uses. */ | |
807e902e KZ |
1635 | c = alloc_cand_and_find_basis (CAND_ADD, gs, rhs1, |
1636 | 0, integer_one_node, TREE_TYPE (rhs1), 0); | |
1637 | c2 = alloc_cand_and_find_basis (CAND_MULT, gs, rhs1, | |
1638 | 0, integer_one_node, TREE_TYPE (rhs1), 0); | |
f9453c07 BS |
1639 | c->next_interp = c2->cand_num; |
1640 | } | |
1641 | ||
1642 | /* Add the first (or only) interpretation to the statement-candidate | |
1643 | mapping. */ | |
1644 | add_cand_for_stmt (gs, c); | |
1645 | } | |
1646 | \f | |
4d9192b5 TS |
1647 | class find_candidates_dom_walker : public dom_walker |
1648 | { | |
1649 | public: | |
1650 | find_candidates_dom_walker (cdi_direction direction) | |
1651 | : dom_walker (direction) {} | |
1652 | virtual void before_dom_children (basic_block); | |
1653 | }; | |
1654 | ||
f9453c07 BS |
1655 | /* Find strength-reduction candidates in block BB. */ |
1656 | ||
4d9192b5 TS |
1657 | void |
1658 | find_candidates_dom_walker::before_dom_children (basic_block bb) | |
f9453c07 BS |
1659 | { |
1660 | bool speed = optimize_bb_for_speed_p (bb); | |
f9453c07 | 1661 | |
538dd0b7 DM |
1662 | for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi); |
1663 | gsi_next (&gsi)) | |
1664 | slsr_process_phi (gsi.phi (), speed); | |
9b92d12b | 1665 | |
538dd0b7 DM |
1666 | for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi); |
1667 | gsi_next (&gsi)) | |
f9453c07 | 1668 | { |
355fe088 | 1669 | gimple *gs = gsi_stmt (gsi); |
f9453c07 | 1670 | |
2749c8f6 BS |
1671 | if (gimple_vuse (gs) && gimple_assign_single_p (gs)) |
1672 | slsr_process_ref (gs); | |
1673 | ||
1674 | else if (is_gimple_assign (gs) | |
1675 | && SCALAR_INT_MODE_P | |
1676 | (TYPE_MODE (TREE_TYPE (gimple_assign_lhs (gs))))) | |
f9453c07 BS |
1677 | { |
1678 | tree rhs1 = NULL_TREE, rhs2 = NULL_TREE; | |
1679 | ||
1680 | switch (gimple_assign_rhs_code (gs)) | |
1681 | { | |
1682 | case MULT_EXPR: | |
1683 | case PLUS_EXPR: | |
1684 | rhs1 = gimple_assign_rhs1 (gs); | |
1685 | rhs2 = gimple_assign_rhs2 (gs); | |
1686 | /* Should never happen, but currently some buggy situations | |
1687 | in earlier phases put constants in rhs1. */ | |
1688 | if (TREE_CODE (rhs1) != SSA_NAME) | |
1689 | continue; | |
1690 | break; | |
1691 | ||
1692 | /* Possible future opportunity: rhs1 of a ptr+ can be | |
1693 | an ADDR_EXPR. */ | |
1694 | case POINTER_PLUS_EXPR: | |
1695 | case MINUS_EXPR: | |
1696 | rhs2 = gimple_assign_rhs2 (gs); | |
1697 | /* Fall-through. */ | |
1698 | ||
d822570f | 1699 | CASE_CONVERT: |
f9453c07 BS |
1700 | case MODIFY_EXPR: |
1701 | case NEGATE_EXPR: | |
1702 | rhs1 = gimple_assign_rhs1 (gs); | |
1703 | if (TREE_CODE (rhs1) != SSA_NAME) | |
1704 | continue; | |
1705 | break; | |
1706 | ||
1707 | default: | |
1708 | ; | |
1709 | } | |
1710 | ||
1711 | switch (gimple_assign_rhs_code (gs)) | |
1712 | { | |
1713 | case MULT_EXPR: | |
1714 | slsr_process_mul (gs, rhs1, rhs2, speed); | |
1715 | break; | |
1716 | ||
1717 | case PLUS_EXPR: | |
1718 | case POINTER_PLUS_EXPR: | |
1719 | case MINUS_EXPR: | |
1720 | slsr_process_add (gs, rhs1, rhs2, speed); | |
1721 | break; | |
1722 | ||
1723 | case NEGATE_EXPR: | |
1724 | slsr_process_neg (gs, rhs1, speed); | |
1725 | break; | |
1726 | ||
d822570f | 1727 | CASE_CONVERT: |
f9453c07 BS |
1728 | slsr_process_cast (gs, rhs1, speed); |
1729 | break; | |
1730 | ||
1731 | case MODIFY_EXPR: | |
1732 | slsr_process_copy (gs, rhs1, speed); | |
1733 | break; | |
1734 | ||
1735 | default: | |
1736 | ; | |
1737 | } | |
1738 | } | |
1739 | } | |
1740 | } | |
1741 | \f | |
1742 | /* Dump a candidate for debug. */ | |
1743 | ||
1744 | static void | |
1745 | dump_candidate (slsr_cand_t c) | |
1746 | { | |
1747 | fprintf (dump_file, "%3d [%d] ", c->cand_num, | |
1748 | gimple_bb (c->cand_stmt)->index); | |
1749 | print_gimple_stmt (dump_file, c->cand_stmt, 0, 0); | |
1750 | switch (c->kind) | |
1751 | { | |
1752 | case CAND_MULT: | |
1753 | fputs (" MULT : (", dump_file); | |
3cfd4469 | 1754 | print_generic_expr (dump_file, c->base_expr, 0); |
f9453c07 | 1755 | fputs (" + ", dump_file); |
807e902e | 1756 | print_decs (c->index, dump_file); |
f9453c07 BS |
1757 | fputs (") * ", dump_file); |
1758 | print_generic_expr (dump_file, c->stride, 0); | |
1759 | fputs (" : ", dump_file); | |
1760 | break; | |
1761 | case CAND_ADD: | |
1762 | fputs (" ADD : ", dump_file); | |
3cfd4469 | 1763 | print_generic_expr (dump_file, c->base_expr, 0); |
f9453c07 | 1764 | fputs (" + (", dump_file); |
807e902e | 1765 | print_decs (c->index, dump_file); |
f9453c07 BS |
1766 | fputs (" * ", dump_file); |
1767 | print_generic_expr (dump_file, c->stride, 0); | |
1768 | fputs (") : ", dump_file); | |
1769 | break; | |
2749c8f6 BS |
1770 | case CAND_REF: |
1771 | fputs (" REF : ", dump_file); | |
3cfd4469 | 1772 | print_generic_expr (dump_file, c->base_expr, 0); |
2749c8f6 BS |
1773 | fputs (" + (", dump_file); |
1774 | print_generic_expr (dump_file, c->stride, 0); | |
1775 | fputs (") + ", dump_file); | |
807e902e | 1776 | print_decs (c->index, dump_file); |
2749c8f6 BS |
1777 | fputs (" : ", dump_file); |
1778 | break; | |
9b92d12b BS |
1779 | case CAND_PHI: |
1780 | fputs (" PHI : ", dump_file); | |
1781 | print_generic_expr (dump_file, c->base_expr, 0); | |
1782 | fputs (" + (unknown * ", dump_file); | |
1783 | print_generic_expr (dump_file, c->stride, 0); | |
1784 | fputs (") : ", dump_file); | |
1785 | break; | |
f9453c07 BS |
1786 | default: |
1787 | gcc_unreachable (); | |
1788 | } | |
1789 | print_generic_expr (dump_file, c->cand_type, 0); | |
1790 | fprintf (dump_file, "\n basis: %d dependent: %d sibling: %d\n", | |
1791 | c->basis, c->dependent, c->sibling); | |
1792 | fprintf (dump_file, " next-interp: %d dead-savings: %d\n", | |
1793 | c->next_interp, c->dead_savings); | |
1794 | if (c->def_phi) | |
9b92d12b | 1795 | fprintf (dump_file, " phi: %d\n", c->def_phi); |
f9453c07 BS |
1796 | fputs ("\n", dump_file); |
1797 | } | |
1798 | ||
1799 | /* Dump the candidate vector for debug. */ | |
1800 | ||
1801 | static void | |
1802 | dump_cand_vec (void) | |
1803 | { | |
1804 | unsigned i; | |
1805 | slsr_cand_t c; | |
1806 | ||
1807 | fprintf (dump_file, "\nStrength reduction candidate vector:\n\n"); | |
1808 | ||
9771b263 | 1809 | FOR_EACH_VEC_ELT (cand_vec, i, c) |
f9453c07 BS |
1810 | dump_candidate (c); |
1811 | } | |
1812 | ||
2749c8f6 | 1813 | /* Callback used to dump the candidate chains hash table. */ |
f9453c07 | 1814 | |
4a8fb1a1 LC |
1815 | int |
1816 | ssa_base_cand_dump_callback (cand_chain **slot, void *ignored ATTRIBUTE_UNUSED) | |
f9453c07 | 1817 | { |
4a8fb1a1 | 1818 | const_cand_chain_t chain = *slot; |
2749c8f6 | 1819 | cand_chain_t p; |
f9453c07 | 1820 | |
3cfd4469 | 1821 | print_generic_expr (dump_file, chain->base_expr, 0); |
2749c8f6 | 1822 | fprintf (dump_file, " -> %d", chain->cand->cand_num); |
f9453c07 | 1823 | |
2749c8f6 BS |
1824 | for (p = chain->next; p; p = p->next) |
1825 | fprintf (dump_file, " -> %d", p->cand->cand_num); | |
f9453c07 | 1826 | |
2749c8f6 BS |
1827 | fputs ("\n", dump_file); |
1828 | return 1; | |
1829 | } | |
f9453c07 | 1830 | |
2749c8f6 | 1831 | /* Dump the candidate chains. */ |
f9453c07 | 1832 | |
2749c8f6 BS |
1833 | static void |
1834 | dump_cand_chains (void) | |
1835 | { | |
1836 | fprintf (dump_file, "\nStrength reduction candidate chains:\n\n"); | |
c203e8a7 TS |
1837 | base_cand_map->traverse_noresize <void *, ssa_base_cand_dump_callback> |
1838 | (NULL); | |
f9453c07 BS |
1839 | fputs ("\n", dump_file); |
1840 | } | |
88ca9ea1 BS |
1841 | |
1842 | /* Dump the increment vector for debug. */ | |
1843 | ||
1844 | static void | |
1845 | dump_incr_vec (void) | |
1846 | { | |
1847 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1848 | { | |
1849 | unsigned i; | |
1850 | ||
1851 | fprintf (dump_file, "\nIncrement vector:\n\n"); | |
1852 | ||
1853 | for (i = 0; i < incr_vec_len; i++) | |
1854 | { | |
1855 | fprintf (dump_file, "%3d increment: ", i); | |
807e902e | 1856 | print_decs (incr_vec[i].incr, dump_file); |
88ca9ea1 BS |
1857 | fprintf (dump_file, "\n count: %d", incr_vec[i].count); |
1858 | fprintf (dump_file, "\n cost: %d", incr_vec[i].cost); | |
1859 | fputs ("\n initializer: ", dump_file); | |
1860 | print_generic_expr (dump_file, incr_vec[i].initializer, 0); | |
1861 | fputs ("\n\n", dump_file); | |
1862 | } | |
1863 | } | |
1864 | } | |
f9453c07 | 1865 | \f |
2749c8f6 BS |
1866 | /* Replace *EXPR in candidate C with an equivalent strength-reduced |
1867 | data reference. */ | |
1868 | ||
1869 | static void | |
1870 | replace_ref (tree *expr, slsr_cand_t c) | |
1871 | { | |
78f6dd68 MJ |
1872 | tree add_expr, mem_ref, acc_type = TREE_TYPE (*expr); |
1873 | unsigned HOST_WIDE_INT misalign; | |
1874 | unsigned align; | |
1875 | ||
1876 | /* Ensure the memory reference carries the minimum alignment | |
1877 | requirement for the data type. See PR58041. */ | |
1878 | get_object_alignment_1 (*expr, &align, &misalign); | |
1879 | if (misalign != 0) | |
1880 | align = (misalign & -misalign); | |
1881 | if (align < TYPE_ALIGN (acc_type)) | |
1882 | acc_type = build_aligned_type (acc_type, align); | |
1883 | ||
1884 | add_expr = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (c->base_expr), | |
1885 | c->base_expr, c->stride); | |
1886 | mem_ref = fold_build2 (MEM_REF, acc_type, add_expr, | |
807e902e | 1887 | wide_int_to_tree (c->cand_type, c->index)); |
78f6dd68 | 1888 | |
2749c8f6 BS |
1889 | /* Gimplify the base addressing expression for the new MEM_REF tree. */ |
1890 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
1891 | TREE_OPERAND (mem_ref, 0) | |
1892 | = force_gimple_operand_gsi (&gsi, TREE_OPERAND (mem_ref, 0), | |
1893 | /*simple_p=*/true, NULL, | |
1894 | /*before=*/true, GSI_SAME_STMT); | |
1895 | copy_ref_info (mem_ref, *expr); | |
1896 | *expr = mem_ref; | |
1897 | update_stmt (c->cand_stmt); | |
1898 | } | |
1899 | ||
1900 | /* Replace CAND_REF candidate C, each sibling of candidate C, and each | |
1901 | dependent of candidate C with an equivalent strength-reduced data | |
1902 | reference. */ | |
1903 | ||
1904 | static void | |
1905 | replace_refs (slsr_cand_t c) | |
1906 | { | |
96d75a2c YZ |
1907 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1908 | { | |
1909 | fputs ("Replacing reference: ", dump_file); | |
1910 | print_gimple_stmt (dump_file, c->cand_stmt, 0, 0); | |
1911 | } | |
1912 | ||
2749c8f6 BS |
1913 | if (gimple_vdef (c->cand_stmt)) |
1914 | { | |
1915 | tree *lhs = gimple_assign_lhs_ptr (c->cand_stmt); | |
1916 | replace_ref (lhs, c); | |
1917 | } | |
1918 | else | |
1919 | { | |
1920 | tree *rhs = gimple_assign_rhs1_ptr (c->cand_stmt); | |
1921 | replace_ref (rhs, c); | |
1922 | } | |
1923 | ||
96d75a2c YZ |
1924 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1925 | { | |
1926 | fputs ("With: ", dump_file); | |
1927 | print_gimple_stmt (dump_file, c->cand_stmt, 0, 0); | |
1928 | fputs ("\n", dump_file); | |
1929 | } | |
1930 | ||
2749c8f6 BS |
1931 | if (c->sibling) |
1932 | replace_refs (lookup_cand (c->sibling)); | |
1933 | ||
1934 | if (c->dependent) | |
1935 | replace_refs (lookup_cand (c->dependent)); | |
1936 | } | |
1937 | ||
9b92d12b BS |
1938 | /* Return TRUE if candidate C is dependent upon a PHI. */ |
1939 | ||
1940 | static bool | |
1941 | phi_dependent_cand_p (slsr_cand_t c) | |
1942 | { | |
1943 | /* A candidate is not necessarily dependent upon a PHI just because | |
1944 | it has a phi definition for its base name. It may have a basis | |
1945 | that relies upon the same phi definition, in which case the PHI | |
1946 | is irrelevant to this candidate. */ | |
1947 | return (c->def_phi | |
1948 | && c->basis | |
1949 | && lookup_cand (c->basis)->def_phi != c->def_phi); | |
1950 | } | |
1951 | ||
f9453c07 BS |
1952 | /* Calculate the increment required for candidate C relative to |
1953 | its basis. */ | |
1954 | ||
807e902e | 1955 | static widest_int |
f9453c07 BS |
1956 | cand_increment (slsr_cand_t c) |
1957 | { | |
1958 | slsr_cand_t basis; | |
1959 | ||
1960 | /* If the candidate doesn't have a basis, just return its own | |
1961 | index. This is useful in record_increments to help us find | |
9b92d12b BS |
1962 | an existing initializer. Also, if the candidate's basis is |
1963 | hidden by a phi, then its own index will be the increment | |
1964 | from the newly introduced phi basis. */ | |
1965 | if (!c->basis || phi_dependent_cand_p (c)) | |
f9453c07 BS |
1966 | return c->index; |
1967 | ||
1968 | basis = lookup_cand (c->basis); | |
3cfd4469 | 1969 | gcc_assert (operand_equal_p (c->base_expr, basis->base_expr, 0)); |
27bcd47c | 1970 | return c->index - basis->index; |
f9453c07 BS |
1971 | } |
1972 | ||
88ca9ea1 BS |
1973 | /* Calculate the increment required for candidate C relative to |
1974 | its basis. If we aren't going to generate pointer arithmetic | |
1975 | for this candidate, return the absolute value of that increment | |
1976 | instead. */ | |
1977 | ||
807e902e | 1978 | static inline widest_int |
88ca9ea1 BS |
1979 | cand_abs_increment (slsr_cand_t c) |
1980 | { | |
807e902e | 1981 | widest_int increment = cand_increment (c); |
88ca9ea1 | 1982 | |
807e902e | 1983 | if (!address_arithmetic_p && wi::neg_p (increment)) |
27bcd47c | 1984 | increment = -increment; |
88ca9ea1 BS |
1985 | |
1986 | return increment; | |
1987 | } | |
1988 | ||
f9453c07 BS |
1989 | /* Return TRUE iff candidate C has already been replaced under |
1990 | another interpretation. */ | |
1991 | ||
1992 | static inline bool | |
1993 | cand_already_replaced (slsr_cand_t c) | |
1994 | { | |
1995 | return (gimple_bb (c->cand_stmt) == 0); | |
1996 | } | |
1997 | ||
9b92d12b BS |
1998 | /* Common logic used by replace_unconditional_candidate and |
1999 | replace_conditional_candidate. */ | |
f9453c07 BS |
2000 | |
2001 | static void | |
807e902e | 2002 | replace_mult_candidate (slsr_cand_t c, tree basis_name, widest_int bump) |
f9453c07 | 2003 | { |
9b92d12b BS |
2004 | tree target_type = TREE_TYPE (gimple_assign_lhs (c->cand_stmt)); |
2005 | enum tree_code cand_code = gimple_assign_rhs_code (c->cand_stmt); | |
2006 | ||
f9453c07 BS |
2007 | /* It is highly unlikely, but possible, that the resulting |
2008 | bump doesn't fit in a HWI. Abandon the replacement | |
9b92d12b BS |
2009 | in this case. This does not affect siblings or dependents |
2010 | of C. Restriction to signed HWI is conservative for unsigned | |
2011 | types but allows for safe negation without twisted logic. */ | |
807e902e | 2012 | if (wi::fits_shwi_p (bump) |
9b92d12b BS |
2013 | && bump.to_shwi () != HOST_WIDE_INT_MIN |
2014 | /* It is not useful to replace casts, copies, or adds of | |
2015 | an SSA name and a constant. */ | |
2016 | && cand_code != MODIFY_EXPR | |
d822570f | 2017 | && !CONVERT_EXPR_CODE_P (cand_code) |
9b92d12b BS |
2018 | && cand_code != PLUS_EXPR |
2019 | && cand_code != POINTER_PLUS_EXPR | |
2020 | && cand_code != MINUS_EXPR) | |
2021 | { | |
2022 | enum tree_code code = PLUS_EXPR; | |
2023 | tree bump_tree; | |
355fe088 | 2024 | gimple *stmt_to_print = NULL; |
9b92d12b BS |
2025 | |
2026 | /* If the basis name and the candidate's LHS have incompatible | |
2027 | types, introduce a cast. */ | |
2028 | if (!useless_type_conversion_p (target_type, TREE_TYPE (basis_name))) | |
a7a7d10e | 2029 | basis_name = introduce_cast_before_cand (c, target_type, basis_name); |
807e902e | 2030 | if (wi::neg_p (bump)) |
9b92d12b BS |
2031 | { |
2032 | code = MINUS_EXPR; | |
2033 | bump = -bump; | |
2034 | } | |
2035 | ||
807e902e | 2036 | bump_tree = wide_int_to_tree (target_type, bump); |
9b92d12b BS |
2037 | |
2038 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2039 | { | |
2040 | fputs ("Replacing: ", dump_file); | |
2041 | print_gimple_stmt (dump_file, c->cand_stmt, 0, 0); | |
2042 | } | |
2043 | ||
807e902e | 2044 | if (bump == 0) |
9b92d12b BS |
2045 | { |
2046 | tree lhs = gimple_assign_lhs (c->cand_stmt); | |
538dd0b7 | 2047 | gassign *copy_stmt = gimple_build_assign (lhs, basis_name); |
9b92d12b BS |
2048 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); |
2049 | gimple_set_location (copy_stmt, gimple_location (c->cand_stmt)); | |
2050 | gsi_replace (&gsi, copy_stmt, false); | |
0100cd3f | 2051 | c->cand_stmt = copy_stmt; |
9b92d12b BS |
2052 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2053 | stmt_to_print = copy_stmt; | |
2054 | } | |
2055 | else | |
2056 | { | |
2057 | tree rhs1, rhs2; | |
2058 | if (cand_code != NEGATE_EXPR) { | |
2059 | rhs1 = gimple_assign_rhs1 (c->cand_stmt); | |
2060 | rhs2 = gimple_assign_rhs2 (c->cand_stmt); | |
2061 | } | |
2062 | if (cand_code != NEGATE_EXPR | |
2063 | && ((operand_equal_p (rhs1, basis_name, 0) | |
2064 | && operand_equal_p (rhs2, bump_tree, 0)) | |
2065 | || (operand_equal_p (rhs1, bump_tree, 0) | |
2066 | && operand_equal_p (rhs2, basis_name, 0)))) | |
2067 | { | |
2068 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2069 | { | |
2070 | fputs ("(duplicate, not actually replacing)", dump_file); | |
2071 | stmt_to_print = c->cand_stmt; | |
2072 | } | |
2073 | } | |
2074 | else | |
2075 | { | |
2076 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
2077 | gimple_assign_set_rhs_with_ops (&gsi, code, | |
2078 | basis_name, bump_tree); | |
2079 | update_stmt (gsi_stmt (gsi)); | |
bb0d2039 | 2080 | c->cand_stmt = gsi_stmt (gsi); |
9b92d12b BS |
2081 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2082 | stmt_to_print = gsi_stmt (gsi); | |
2083 | } | |
2084 | } | |
2085 | ||
2086 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2087 | { | |
2088 | fputs ("With: ", dump_file); | |
2089 | print_gimple_stmt (dump_file, stmt_to_print, 0, 0); | |
2090 | fputs ("\n", dump_file); | |
2091 | } | |
2092 | } | |
2093 | } | |
2094 | ||
2095 | /* Replace candidate C with an add or subtract. Note that we only | |
2096 | operate on CAND_MULTs with known strides, so we will never generate | |
2097 | a POINTER_PLUS_EXPR. Each candidate X = (B + i) * S is replaced by | |
2098 | X = Y + ((i - i') * S), as described in the module commentary. The | |
2099 | folded value ((i - i') * S) is referred to here as the "bump." */ | |
2100 | ||
2101 | static void | |
2102 | replace_unconditional_candidate (slsr_cand_t c) | |
2103 | { | |
2104 | slsr_cand_t basis; | |
9b92d12b BS |
2105 | |
2106 | if (cand_already_replaced (c)) | |
f9453c07 BS |
2107 | return; |
2108 | ||
2109 | basis = lookup_cand (c->basis); | |
807e902e | 2110 | widest_int bump = cand_increment (c) * wi::to_widest (c->stride); |
9b92d12b | 2111 | |
a7a7d10e | 2112 | replace_mult_candidate (c, gimple_assign_lhs (basis->cand_stmt), bump); |
9b92d12b BS |
2113 | } |
2114 | \f | |
7bf55a70 BS |
2115 | /* Return the index in the increment vector of the given INCREMENT, |
2116 | or -1 if not found. The latter can occur if more than | |
2117 | MAX_INCR_VEC_LEN increments have been found. */ | |
9b92d12b | 2118 | |
7bf55a70 | 2119 | static inline int |
807e902e | 2120 | incr_vec_index (const widest_int &increment) |
9b92d12b BS |
2121 | { |
2122 | unsigned i; | |
2123 | ||
2124 | for (i = 0; i < incr_vec_len && increment != incr_vec[i].incr; i++) | |
2125 | ; | |
2126 | ||
7bf55a70 BS |
2127 | if (i < incr_vec_len) |
2128 | return i; | |
2129 | else | |
2130 | return -1; | |
9b92d12b BS |
2131 | } |
2132 | ||
2133 | /* Create a new statement along edge E to add BASIS_NAME to the product | |
2134 | of INCREMENT and the stride of candidate C. Create and return a new | |
2135 | SSA name from *VAR to be used as the LHS of the new statement. | |
2136 | KNOWN_STRIDE is true iff C's stride is a constant. */ | |
2137 | ||
2138 | static tree | |
2139 | create_add_on_incoming_edge (slsr_cand_t c, tree basis_name, | |
807e902e | 2140 | widest_int increment, edge e, location_t loc, |
9b92d12b BS |
2141 | bool known_stride) |
2142 | { | |
2143 | basic_block insert_bb; | |
2144 | gimple_stmt_iterator gsi; | |
2145 | tree lhs, basis_type; | |
538dd0b7 | 2146 | gassign *new_stmt; |
9b92d12b BS |
2147 | |
2148 | /* If the add candidate along this incoming edge has the same | |
2149 | index as C's hidden basis, the hidden basis represents this | |
2150 | edge correctly. */ | |
807e902e | 2151 | if (increment == 0) |
9b92d12b BS |
2152 | return basis_name; |
2153 | ||
2154 | basis_type = TREE_TYPE (basis_name); | |
2155 | lhs = make_temp_ssa_name (basis_type, NULL, "slsr"); | |
2156 | ||
2157 | if (known_stride) | |
7139194b | 2158 | { |
9b92d12b BS |
2159 | tree bump_tree; |
2160 | enum tree_code code = PLUS_EXPR; | |
807e902e KZ |
2161 | widest_int bump = increment * wi::to_widest (c->stride); |
2162 | if (wi::neg_p (bump)) | |
9b92d12b BS |
2163 | { |
2164 | code = MINUS_EXPR; | |
2165 | bump = -bump; | |
2166 | } | |
2167 | ||
807e902e | 2168 | bump_tree = wide_int_to_tree (basis_type, bump); |
0d0e4a03 | 2169 | new_stmt = gimple_build_assign (lhs, code, basis_name, bump_tree); |
7139194b AH |
2170 | } |
2171 | else | |
2172 | { | |
7bf55a70 | 2173 | int i; |
807e902e | 2174 | bool negate_incr = (!address_arithmetic_p && wi::neg_p (increment)); |
9b92d12b | 2175 | i = incr_vec_index (negate_incr ? -increment : increment); |
7bf55a70 | 2176 | gcc_assert (i >= 0); |
f9453c07 | 2177 | |
9b92d12b BS |
2178 | if (incr_vec[i].initializer) |
2179 | { | |
2180 | enum tree_code code = negate_incr ? MINUS_EXPR : PLUS_EXPR; | |
0d0e4a03 JJ |
2181 | new_stmt = gimple_build_assign (lhs, code, basis_name, |
2182 | incr_vec[i].initializer); | |
9b92d12b | 2183 | } |
807e902e | 2184 | else if (increment == 1) |
0d0e4a03 | 2185 | new_stmt = gimple_build_assign (lhs, PLUS_EXPR, basis_name, c->stride); |
807e902e | 2186 | else if (increment == -1) |
0d0e4a03 JJ |
2187 | new_stmt = gimple_build_assign (lhs, MINUS_EXPR, basis_name, |
2188 | c->stride); | |
9b92d12b BS |
2189 | else |
2190 | gcc_unreachable (); | |
f9453c07 BS |
2191 | } |
2192 | ||
9b92d12b BS |
2193 | insert_bb = single_succ_p (e->src) ? e->src : split_edge (e); |
2194 | gsi = gsi_last_bb (insert_bb); | |
2195 | ||
2196 | if (!gsi_end_p (gsi) && is_ctrl_stmt (gsi_stmt (gsi))) | |
2197 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); | |
2198 | else | |
2199 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); | |
2200 | ||
2201 | gimple_set_location (new_stmt, loc); | |
f9453c07 BS |
2202 | |
2203 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2204 | { | |
9b92d12b BS |
2205 | fprintf (dump_file, "Inserting in block %d: ", insert_bb->index); |
2206 | print_gimple_stmt (dump_file, new_stmt, 0, 0); | |
f9453c07 BS |
2207 | } |
2208 | ||
9b92d12b BS |
2209 | return lhs; |
2210 | } | |
2211 | ||
2212 | /* Given a candidate C with BASIS_NAME being the LHS of C's basis which | |
2213 | is hidden by the phi node FROM_PHI, create a new phi node in the same | |
2214 | block as FROM_PHI. The new phi is suitable for use as a basis by C, | |
2215 | with its phi arguments representing conditional adjustments to the | |
2216 | hidden basis along conditional incoming paths. Those adjustments are | |
2217 | made by creating add statements (and sometimes recursively creating | |
2218 | phis) along those incoming paths. LOC is the location to attach to | |
2219 | the introduced statements. KNOWN_STRIDE is true iff C's stride is a | |
2220 | constant. */ | |
2221 | ||
2222 | static tree | |
355fe088 | 2223 | create_phi_basis (slsr_cand_t c, gimple *from_phi, tree basis_name, |
9b92d12b BS |
2224 | location_t loc, bool known_stride) |
2225 | { | |
2226 | int i; | |
2227 | tree name, phi_arg; | |
538dd0b7 | 2228 | gphi *phi; |
9b92d12b BS |
2229 | slsr_cand_t basis = lookup_cand (c->basis); |
2230 | int nargs = gimple_phi_num_args (from_phi); | |
2231 | basic_block phi_bb = gimple_bb (from_phi); | |
2232 | slsr_cand_t phi_cand = base_cand_from_table (gimple_phi_result (from_phi)); | |
c8189787 | 2233 | auto_vec<tree> phi_args (nargs); |
9b92d12b BS |
2234 | |
2235 | /* Process each argument of the existing phi that represents | |
2236 | conditionally-executed add candidates. */ | |
2237 | for (i = 0; i < nargs; i++) | |
f9453c07 | 2238 | { |
9b92d12b BS |
2239 | edge e = (*phi_bb->preds)[i]; |
2240 | tree arg = gimple_phi_arg_def (from_phi, i); | |
2241 | tree feeding_def; | |
2242 | ||
2243 | /* If the phi argument is the base name of the CAND_PHI, then | |
2244 | this incoming arc should use the hidden basis. */ | |
2245 | if (operand_equal_p (arg, phi_cand->base_expr, 0)) | |
807e902e | 2246 | if (basis->index == 0) |
9b92d12b BS |
2247 | feeding_def = gimple_assign_lhs (basis->cand_stmt); |
2248 | else | |
2249 | { | |
807e902e | 2250 | widest_int incr = -basis->index; |
9b92d12b BS |
2251 | feeding_def = create_add_on_incoming_edge (c, basis_name, incr, |
2252 | e, loc, known_stride); | |
2253 | } | |
2254 | else | |
f9453c07 | 2255 | { |
355fe088 | 2256 | gimple *arg_def = SSA_NAME_DEF_STMT (arg); |
9b92d12b BS |
2257 | |
2258 | /* If there is another phi along this incoming edge, we must | |
2259 | process it in the same fashion to ensure that all basis | |
2260 | adjustments are made along its incoming edges. */ | |
2261 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
2262 | feeding_def = create_phi_basis (c, arg_def, basis_name, | |
2263 | loc, known_stride); | |
2264 | else | |
f9453c07 | 2265 | { |
9b92d12b | 2266 | slsr_cand_t arg_cand = base_cand_from_table (arg); |
807e902e | 2267 | widest_int diff = arg_cand->index - basis->index; |
9b92d12b BS |
2268 | feeding_def = create_add_on_incoming_edge (c, basis_name, diff, |
2269 | e, loc, known_stride); | |
f9453c07 BS |
2270 | } |
2271 | } | |
9b92d12b BS |
2272 | |
2273 | /* Because of recursion, we need to save the arguments in a vector | |
2274 | so we can create the PHI statement all at once. Otherwise the | |
2275 | storage for the half-created PHI can be reclaimed. */ | |
2276 | phi_args.safe_push (feeding_def); | |
f9453c07 | 2277 | } |
9b92d12b BS |
2278 | |
2279 | /* Create the new phi basis. */ | |
2280 | name = make_temp_ssa_name (TREE_TYPE (basis_name), NULL, "slsr"); | |
2281 | phi = create_phi_node (name, phi_bb); | |
2282 | SSA_NAME_DEF_STMT (name) = phi; | |
2283 | ||
2284 | FOR_EACH_VEC_ELT (phi_args, i, phi_arg) | |
2285 | { | |
2286 | edge e = (*phi_bb->preds)[i]; | |
2287 | add_phi_arg (phi, phi_arg, e, loc); | |
2288 | } | |
2289 | ||
2290 | update_stmt (phi); | |
2291 | ||
f9453c07 BS |
2292 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2293 | { | |
9b92d12b BS |
2294 | fputs ("Introducing new phi basis: ", dump_file); |
2295 | print_gimple_stmt (dump_file, phi, 0, 0); | |
f9453c07 | 2296 | } |
9b92d12b BS |
2297 | |
2298 | return name; | |
f9453c07 BS |
2299 | } |
2300 | ||
9b92d12b BS |
2301 | /* Given a candidate C whose basis is hidden by at least one intervening |
2302 | phi, introduce a matching number of new phis to represent its basis | |
2303 | adjusted by conditional increments along possible incoming paths. Then | |
2304 | replace C as though it were an unconditional candidate, using the new | |
2305 | basis. */ | |
f9453c07 BS |
2306 | |
2307 | static void | |
9b92d12b | 2308 | replace_conditional_candidate (slsr_cand_t c) |
f9453c07 | 2309 | { |
a7a7d10e | 2310 | tree basis_name, name; |
9b92d12b BS |
2311 | slsr_cand_t basis; |
2312 | location_t loc; | |
f9453c07 | 2313 | |
9b92d12b BS |
2314 | /* Look up the LHS SSA name from C's basis. This will be the |
2315 | RHS1 of the adds we will introduce to create new phi arguments. */ | |
2316 | basis = lookup_cand (c->basis); | |
2317 | basis_name = gimple_assign_lhs (basis->cand_stmt); | |
f9453c07 | 2318 | |
9b92d12b BS |
2319 | /* Create a new phi statement which will represent C's true basis |
2320 | after the transformation is complete. */ | |
2321 | loc = gimple_location (c->cand_stmt); | |
2322 | name = create_phi_basis (c, lookup_cand (c->def_phi)->cand_stmt, | |
2323 | basis_name, loc, KNOWN_STRIDE); | |
2324 | /* Replace C with an add of the new basis phi and a constant. */ | |
807e902e | 2325 | widest_int bump = c->index * wi::to_widest (c->stride); |
f9453c07 | 2326 | |
a7a7d10e | 2327 | replace_mult_candidate (c, name, bump); |
f9453c07 | 2328 | } |
88ca9ea1 | 2329 | |
9b92d12b BS |
2330 | /* Compute the expected costs of inserting basis adjustments for |
2331 | candidate C with phi-definition PHI. The cost of inserting | |
2332 | one adjustment is given by ONE_ADD_COST. If PHI has arguments | |
2333 | which are themselves phi results, recursively calculate costs | |
2334 | for those phis as well. */ | |
2335 | ||
2336 | static int | |
355fe088 | 2337 | phi_add_costs (gimple *phi, slsr_cand_t c, int one_add_cost) |
88ca9ea1 BS |
2338 | { |
2339 | unsigned i; | |
9b92d12b BS |
2340 | int cost = 0; |
2341 | slsr_cand_t phi_cand = base_cand_from_table (gimple_phi_result (phi)); | |
88ca9ea1 | 2342 | |
0100cd3f BS |
2343 | /* If we work our way back to a phi that isn't dominated by the hidden |
2344 | basis, this isn't a candidate for replacement. Indicate this by | |
2345 | returning an unreasonably high cost. It's not easy to detect | |
2346 | these situations when determining the basis, so we defer the | |
2347 | decision until now. */ | |
2348 | basic_block phi_bb = gimple_bb (phi); | |
2349 | slsr_cand_t basis = lookup_cand (c->basis); | |
2350 | basic_block basis_bb = gimple_bb (basis->cand_stmt); | |
2351 | ||
2352 | if (phi_bb == basis_bb || !dominated_by_p (CDI_DOMINATORS, phi_bb, basis_bb)) | |
2353 | return COST_INFINITE; | |
2354 | ||
9b92d12b BS |
2355 | for (i = 0; i < gimple_phi_num_args (phi); i++) |
2356 | { | |
2357 | tree arg = gimple_phi_arg_def (phi, i); | |
2358 | ||
2359 | if (arg != phi_cand->base_expr) | |
2360 | { | |
355fe088 | 2361 | gimple *arg_def = SSA_NAME_DEF_STMT (arg); |
9b92d12b BS |
2362 | |
2363 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
2364 | cost += phi_add_costs (arg_def, c, one_add_cost); | |
2365 | else | |
2366 | { | |
2367 | slsr_cand_t arg_cand = base_cand_from_table (arg); | |
2368 | ||
2369 | if (arg_cand->index != c->index) | |
2370 | cost += one_add_cost; | |
2371 | } | |
2372 | } | |
2373 | } | |
2374 | ||
2375 | return cost; | |
88ca9ea1 BS |
2376 | } |
2377 | ||
9b92d12b BS |
2378 | /* For candidate C, each sibling of candidate C, and each dependent of |
2379 | candidate C, determine whether the candidate is dependent upon a | |
2380 | phi that hides its basis. If not, replace the candidate unconditionally. | |
2381 | Otherwise, determine whether the cost of introducing compensation code | |
2382 | for the candidate is offset by the gains from strength reduction. If | |
2383 | so, replace the candidate and introduce the compensation code. */ | |
2384 | ||
2385 | static void | |
2386 | replace_uncond_cands_and_profitable_phis (slsr_cand_t c) | |
2387 | { | |
2388 | if (phi_dependent_cand_p (c)) | |
2389 | { | |
2390 | if (c->kind == CAND_MULT) | |
2391 | { | |
2392 | /* A candidate dependent upon a phi will replace a multiply by | |
2393 | a constant with an add, and will insert at most one add for | |
2394 | each phi argument. Add these costs with the potential dead-code | |
2395 | savings to determine profitability. */ | |
2396 | bool speed = optimize_bb_for_speed_p (gimple_bb (c->cand_stmt)); | |
2397 | int mult_savings = stmt_cost (c->cand_stmt, speed); | |
355fe088 | 2398 | gimple *phi = lookup_cand (c->def_phi)->cand_stmt; |
9b92d12b BS |
2399 | tree phi_result = gimple_phi_result (phi); |
2400 | int one_add_cost = add_cost (speed, | |
2401 | TYPE_MODE (TREE_TYPE (phi_result))); | |
2402 | int add_costs = one_add_cost + phi_add_costs (phi, c, one_add_cost); | |
2403 | int cost = add_costs - mult_savings - c->dead_savings; | |
2404 | ||
2405 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2406 | { | |
2407 | fprintf (dump_file, " Conditional candidate %d:\n", c->cand_num); | |
2408 | fprintf (dump_file, " add_costs = %d\n", add_costs); | |
2409 | fprintf (dump_file, " mult_savings = %d\n", mult_savings); | |
2410 | fprintf (dump_file, " dead_savings = %d\n", c->dead_savings); | |
2411 | fprintf (dump_file, " cost = %d\n", cost); | |
2412 | if (cost <= COST_NEUTRAL) | |
2413 | fputs (" Replacing...\n", dump_file); | |
2414 | else | |
2415 | fputs (" Not replaced.\n", dump_file); | |
2416 | } | |
2417 | ||
2418 | if (cost <= COST_NEUTRAL) | |
2419 | replace_conditional_candidate (c); | |
2420 | } | |
2421 | } | |
2422 | else | |
2423 | replace_unconditional_candidate (c); | |
2424 | ||
2425 | if (c->sibling) | |
2426 | replace_uncond_cands_and_profitable_phis (lookup_cand (c->sibling)); | |
2427 | ||
2428 | if (c->dependent) | |
2429 | replace_uncond_cands_and_profitable_phis (lookup_cand (c->dependent)); | |
2430 | } | |
2431 | \f | |
88ca9ea1 BS |
2432 | /* Count the number of candidates in the tree rooted at C that have |
2433 | not already been replaced under other interpretations. */ | |
2434 | ||
1dc3d6e9 | 2435 | static int |
88ca9ea1 BS |
2436 | count_candidates (slsr_cand_t c) |
2437 | { | |
2438 | unsigned count = cand_already_replaced (c) ? 0 : 1; | |
2439 | ||
2440 | if (c->sibling) | |
2441 | count += count_candidates (lookup_cand (c->sibling)); | |
2442 | ||
2443 | if (c->dependent) | |
2444 | count += count_candidates (lookup_cand (c->dependent)); | |
2445 | ||
2446 | return count; | |
2447 | } | |
2448 | ||
2449 | /* Increase the count of INCREMENT by one in the increment vector. | |
9b92d12b BS |
2450 | INCREMENT is associated with candidate C. If INCREMENT is to be |
2451 | conditionally executed as part of a conditional candidate replacement, | |
2452 | IS_PHI_ADJUST is true, otherwise false. If an initializer | |
88ca9ea1 BS |
2453 | T_0 = stride * I is provided by a candidate that dominates all |
2454 | candidates with the same increment, also record T_0 for subsequent use. */ | |
2455 | ||
2456 | static void | |
807e902e | 2457 | record_increment (slsr_cand_t c, widest_int increment, bool is_phi_adjust) |
88ca9ea1 BS |
2458 | { |
2459 | bool found = false; | |
2460 | unsigned i; | |
2461 | ||
2462 | /* Treat increments that differ only in sign as identical so as to | |
2463 | share initializers, unless we are generating pointer arithmetic. */ | |
807e902e | 2464 | if (!address_arithmetic_p && wi::neg_p (increment)) |
27bcd47c | 2465 | increment = -increment; |
88ca9ea1 BS |
2466 | |
2467 | for (i = 0; i < incr_vec_len; i++) | |
2468 | { | |
27bcd47c | 2469 | if (incr_vec[i].incr == increment) |
88ca9ea1 BS |
2470 | { |
2471 | incr_vec[i].count++; | |
2472 | found = true; | |
2473 | ||
2474 | /* If we previously recorded an initializer that doesn't | |
2475 | dominate this candidate, it's not going to be useful to | |
2476 | us after all. */ | |
2477 | if (incr_vec[i].initializer | |
2478 | && !dominated_by_p (CDI_DOMINATORS, | |
2479 | gimple_bb (c->cand_stmt), | |
2480 | incr_vec[i].init_bb)) | |
2481 | { | |
2482 | incr_vec[i].initializer = NULL_TREE; | |
2483 | incr_vec[i].init_bb = NULL; | |
2484 | } | |
2485 | ||
2486 | break; | |
2487 | } | |
2488 | } | |
2489 | ||
7bf55a70 | 2490 | if (!found && incr_vec_len < MAX_INCR_VEC_LEN - 1) |
88ca9ea1 BS |
2491 | { |
2492 | /* The first time we see an increment, create the entry for it. | |
2493 | If this is the root candidate which doesn't have a basis, set | |
2494 | the count to zero. We're only processing it so it can possibly | |
2495 | provide an initializer for other candidates. */ | |
2496 | incr_vec[incr_vec_len].incr = increment; | |
9b92d12b | 2497 | incr_vec[incr_vec_len].count = c->basis || is_phi_adjust ? 1 : 0; |
88ca9ea1 BS |
2498 | incr_vec[incr_vec_len].cost = COST_INFINITE; |
2499 | ||
2500 | /* Optimistically record the first occurrence of this increment | |
2501 | as providing an initializer (if it does); we will revise this | |
2502 | opinion later if it doesn't dominate all other occurrences. | |
9b92d12b BS |
2503 | Exception: increments of -1, 0, 1 never need initializers; |
2504 | and phi adjustments don't ever provide initializers. */ | |
88ca9ea1 | 2505 | if (c->kind == CAND_ADD |
9b92d12b | 2506 | && !is_phi_adjust |
27bcd47c | 2507 | && c->index == increment |
807e902e KZ |
2508 | && (wi::gts_p (increment, 1) |
2509 | || wi::lts_p (increment, -1)) | |
7b8265ba JJ |
2510 | && (gimple_assign_rhs_code (c->cand_stmt) == PLUS_EXPR |
2511 | || gimple_assign_rhs_code (c->cand_stmt) == POINTER_PLUS_EXPR)) | |
88ca9ea1 | 2512 | { |
7b8265ba | 2513 | tree t0 = NULL_TREE; |
88ca9ea1 BS |
2514 | tree rhs1 = gimple_assign_rhs1 (c->cand_stmt); |
2515 | tree rhs2 = gimple_assign_rhs2 (c->cand_stmt); | |
2516 | if (operand_equal_p (rhs1, c->base_expr, 0)) | |
2517 | t0 = rhs2; | |
7b8265ba | 2518 | else if (operand_equal_p (rhs2, c->base_expr, 0)) |
88ca9ea1 | 2519 | t0 = rhs1; |
7b8265ba JJ |
2520 | if (t0 |
2521 | && SSA_NAME_DEF_STMT (t0) | |
2522 | && gimple_bb (SSA_NAME_DEF_STMT (t0))) | |
88ca9ea1 BS |
2523 | { |
2524 | incr_vec[incr_vec_len].initializer = t0; | |
2525 | incr_vec[incr_vec_len++].init_bb | |
2526 | = gimple_bb (SSA_NAME_DEF_STMT (t0)); | |
2527 | } | |
2528 | else | |
2529 | { | |
2530 | incr_vec[incr_vec_len].initializer = NULL_TREE; | |
2531 | incr_vec[incr_vec_len++].init_bb = NULL; | |
2532 | } | |
2533 | } | |
2534 | else | |
2535 | { | |
2536 | incr_vec[incr_vec_len].initializer = NULL_TREE; | |
2537 | incr_vec[incr_vec_len++].init_bb = NULL; | |
2538 | } | |
2539 | } | |
2540 | } | |
2541 | ||
9b92d12b BS |
2542 | /* Given phi statement PHI that hides a candidate from its BASIS, find |
2543 | the increments along each incoming arc (recursively handling additional | |
2544 | phis that may be present) and record them. These increments are the | |
2545 | difference in index between the index-adjusting statements and the | |
2546 | index of the basis. */ | |
2547 | ||
2548 | static void | |
355fe088 | 2549 | record_phi_increments (slsr_cand_t basis, gimple *phi) |
9b92d12b BS |
2550 | { |
2551 | unsigned i; | |
2552 | slsr_cand_t phi_cand = base_cand_from_table (gimple_phi_result (phi)); | |
2553 | ||
2554 | for (i = 0; i < gimple_phi_num_args (phi); i++) | |
2555 | { | |
2556 | tree arg = gimple_phi_arg_def (phi, i); | |
2557 | ||
2558 | if (!operand_equal_p (arg, phi_cand->base_expr, 0)) | |
2559 | { | |
355fe088 | 2560 | gimple *arg_def = SSA_NAME_DEF_STMT (arg); |
9b92d12b BS |
2561 | |
2562 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
2563 | record_phi_increments (basis, arg_def); | |
2564 | else | |
2565 | { | |
2566 | slsr_cand_t arg_cand = base_cand_from_table (arg); | |
807e902e | 2567 | widest_int diff = arg_cand->index - basis->index; |
9b92d12b BS |
2568 | record_increment (arg_cand, diff, PHI_ADJUST); |
2569 | } | |
2570 | } | |
2571 | } | |
2572 | } | |
2573 | ||
88ca9ea1 BS |
2574 | /* Determine how many times each unique increment occurs in the set |
2575 | of candidates rooted at C's parent, recording the data in the | |
2576 | increment vector. For each unique increment I, if an initializer | |
2577 | T_0 = stride * I is provided by a candidate that dominates all | |
2578 | candidates with the same increment, also record T_0 for subsequent | |
2579 | use. */ | |
2580 | ||
2581 | static void | |
2582 | record_increments (slsr_cand_t c) | |
2583 | { | |
2584 | if (!cand_already_replaced (c)) | |
9b92d12b BS |
2585 | { |
2586 | if (!phi_dependent_cand_p (c)) | |
2587 | record_increment (c, cand_increment (c), NOT_PHI_ADJUST); | |
2588 | else | |
2589 | { | |
2590 | /* A candidate with a basis hidden by a phi will have one | |
2591 | increment for its relationship to the index represented by | |
2592 | the phi, and potentially additional increments along each | |
2593 | incoming edge. For the root of the dependency tree (which | |
2594 | has no basis), process just the initial index in case it has | |
2595 | an initializer that can be used by subsequent candidates. */ | |
2596 | record_increment (c, c->index, NOT_PHI_ADJUST); | |
2597 | ||
2598 | if (c->basis) | |
2599 | record_phi_increments (lookup_cand (c->basis), | |
2600 | lookup_cand (c->def_phi)->cand_stmt); | |
2601 | } | |
2602 | } | |
88ca9ea1 BS |
2603 | |
2604 | if (c->sibling) | |
2605 | record_increments (lookup_cand (c->sibling)); | |
2606 | ||
2607 | if (c->dependent) | |
2608 | record_increments (lookup_cand (c->dependent)); | |
2609 | } | |
2610 | ||
9b92d12b BS |
2611 | /* Add up and return the costs of introducing add statements that |
2612 | require the increment INCR on behalf of candidate C and phi | |
2613 | statement PHI. Accumulate into *SAVINGS the potential savings | |
2614 | from removing existing statements that feed PHI and have no other | |
2615 | uses. */ | |
2616 | ||
2617 | static int | |
355fe088 TS |
2618 | phi_incr_cost (slsr_cand_t c, const widest_int &incr, gimple *phi, |
2619 | int *savings) | |
9b92d12b BS |
2620 | { |
2621 | unsigned i; | |
2622 | int cost = 0; | |
2623 | slsr_cand_t basis = lookup_cand (c->basis); | |
2624 | slsr_cand_t phi_cand = base_cand_from_table (gimple_phi_result (phi)); | |
2625 | ||
2626 | for (i = 0; i < gimple_phi_num_args (phi); i++) | |
2627 | { | |
2628 | tree arg = gimple_phi_arg_def (phi, i); | |
2629 | ||
2630 | if (!operand_equal_p (arg, phi_cand->base_expr, 0)) | |
2631 | { | |
355fe088 | 2632 | gimple *arg_def = SSA_NAME_DEF_STMT (arg); |
9b92d12b BS |
2633 | |
2634 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
2635 | { | |
2636 | int feeding_savings = 0; | |
2637 | cost += phi_incr_cost (c, incr, arg_def, &feeding_savings); | |
2638 | if (has_single_use (gimple_phi_result (arg_def))) | |
2639 | *savings += feeding_savings; | |
2640 | } | |
2641 | else | |
2642 | { | |
2643 | slsr_cand_t arg_cand = base_cand_from_table (arg); | |
807e902e | 2644 | widest_int diff = arg_cand->index - basis->index; |
9b92d12b BS |
2645 | |
2646 | if (incr == diff) | |
2647 | { | |
2648 | tree basis_lhs = gimple_assign_lhs (basis->cand_stmt); | |
2649 | tree lhs = gimple_assign_lhs (arg_cand->cand_stmt); | |
2650 | cost += add_cost (true, TYPE_MODE (TREE_TYPE (basis_lhs))); | |
2651 | if (has_single_use (lhs)) | |
2652 | *savings += stmt_cost (arg_cand->cand_stmt, true); | |
2653 | } | |
2654 | } | |
2655 | } | |
2656 | } | |
2657 | ||
2658 | return cost; | |
2659 | } | |
2660 | ||
88ca9ea1 BS |
2661 | /* Return the first candidate in the tree rooted at C that has not |
2662 | already been replaced, favoring siblings over dependents. */ | |
2663 | ||
2664 | static slsr_cand_t | |
2665 | unreplaced_cand_in_tree (slsr_cand_t c) | |
2666 | { | |
2667 | if (!cand_already_replaced (c)) | |
2668 | return c; | |
2669 | ||
2670 | if (c->sibling) | |
2671 | { | |
2672 | slsr_cand_t sib = unreplaced_cand_in_tree (lookup_cand (c->sibling)); | |
2673 | if (sib) | |
2674 | return sib; | |
2675 | } | |
2676 | ||
2677 | if (c->dependent) | |
2678 | { | |
2679 | slsr_cand_t dep = unreplaced_cand_in_tree (lookup_cand (c->dependent)); | |
2680 | if (dep) | |
2681 | return dep; | |
2682 | } | |
2683 | ||
2684 | return NULL; | |
2685 | } | |
2686 | ||
2687 | /* Return TRUE if the candidates in the tree rooted at C should be | |
2688 | optimized for speed, else FALSE. We estimate this based on the block | |
2689 | containing the most dominant candidate in the tree that has not yet | |
2690 | been replaced. */ | |
2691 | ||
2692 | static bool | |
2693 | optimize_cands_for_speed_p (slsr_cand_t c) | |
2694 | { | |
2695 | slsr_cand_t c2 = unreplaced_cand_in_tree (c); | |
2696 | gcc_assert (c2); | |
2697 | return optimize_bb_for_speed_p (gimple_bb (c2->cand_stmt)); | |
2698 | } | |
2699 | ||
2700 | /* Add COST_IN to the lowest cost of any dependent path starting at | |
2701 | candidate C or any of its siblings, counting only candidates along | |
2702 | such paths with increment INCR. Assume that replacing a candidate | |
2703 | reduces cost by REPL_SAVINGS. Also account for savings from any | |
9b92d12b BS |
2704 | statements that would go dead. If COUNT_PHIS is true, include |
2705 | costs of introducing feeding statements for conditional candidates. */ | |
88ca9ea1 BS |
2706 | |
2707 | static int | |
9b92d12b | 2708 | lowest_cost_path (int cost_in, int repl_savings, slsr_cand_t c, |
807e902e | 2709 | const widest_int &incr, bool count_phis) |
88ca9ea1 | 2710 | { |
9b92d12b | 2711 | int local_cost, sib_cost, savings = 0; |
807e902e | 2712 | widest_int cand_incr = cand_abs_increment (c); |
88ca9ea1 BS |
2713 | |
2714 | if (cand_already_replaced (c)) | |
2715 | local_cost = cost_in; | |
27bcd47c | 2716 | else if (incr == cand_incr) |
88ca9ea1 BS |
2717 | local_cost = cost_in - repl_savings - c->dead_savings; |
2718 | else | |
2719 | local_cost = cost_in - c->dead_savings; | |
2720 | ||
9b92d12b BS |
2721 | if (count_phis |
2722 | && phi_dependent_cand_p (c) | |
2723 | && !cand_already_replaced (c)) | |
2724 | { | |
355fe088 | 2725 | gimple *phi = lookup_cand (c->def_phi)->cand_stmt; |
9b92d12b BS |
2726 | local_cost += phi_incr_cost (c, incr, phi, &savings); |
2727 | ||
2728 | if (has_single_use (gimple_phi_result (phi))) | |
2729 | local_cost -= savings; | |
2730 | } | |
2731 | ||
88ca9ea1 BS |
2732 | if (c->dependent) |
2733 | local_cost = lowest_cost_path (local_cost, repl_savings, | |
9b92d12b BS |
2734 | lookup_cand (c->dependent), incr, |
2735 | count_phis); | |
88ca9ea1 BS |
2736 | |
2737 | if (c->sibling) | |
2738 | { | |
2739 | sib_cost = lowest_cost_path (cost_in, repl_savings, | |
9b92d12b BS |
2740 | lookup_cand (c->sibling), incr, |
2741 | count_phis); | |
88ca9ea1 BS |
2742 | local_cost = MIN (local_cost, sib_cost); |
2743 | } | |
2744 | ||
2745 | return local_cost; | |
2746 | } | |
2747 | ||
2748 | /* Compute the total savings that would accrue from all replacements | |
2749 | in the candidate tree rooted at C, counting only candidates with | |
2750 | increment INCR. Assume that replacing a candidate reduces cost | |
2751 | by REPL_SAVINGS. Also account for savings from statements that | |
2752 | would go dead. */ | |
2753 | ||
2754 | static int | |
807e902e | 2755 | total_savings (int repl_savings, slsr_cand_t c, const widest_int &incr, |
9b92d12b | 2756 | bool count_phis) |
88ca9ea1 BS |
2757 | { |
2758 | int savings = 0; | |
807e902e | 2759 | widest_int cand_incr = cand_abs_increment (c); |
88ca9ea1 | 2760 | |
27bcd47c | 2761 | if (incr == cand_incr && !cand_already_replaced (c)) |
88ca9ea1 BS |
2762 | savings += repl_savings + c->dead_savings; |
2763 | ||
9b92d12b BS |
2764 | if (count_phis |
2765 | && phi_dependent_cand_p (c) | |
2766 | && !cand_already_replaced (c)) | |
2767 | { | |
2768 | int phi_savings = 0; | |
355fe088 | 2769 | gimple *phi = lookup_cand (c->def_phi)->cand_stmt; |
9b92d12b BS |
2770 | savings -= phi_incr_cost (c, incr, phi, &phi_savings); |
2771 | ||
2772 | if (has_single_use (gimple_phi_result (phi))) | |
2773 | savings += phi_savings; | |
2774 | } | |
2775 | ||
88ca9ea1 | 2776 | if (c->dependent) |
9b92d12b BS |
2777 | savings += total_savings (repl_savings, lookup_cand (c->dependent), incr, |
2778 | count_phis); | |
88ca9ea1 BS |
2779 | |
2780 | if (c->sibling) | |
9b92d12b BS |
2781 | savings += total_savings (repl_savings, lookup_cand (c->sibling), incr, |
2782 | count_phis); | |
88ca9ea1 BS |
2783 | |
2784 | return savings; | |
2785 | } | |
2786 | ||
2787 | /* Use target-specific costs to determine and record which increments | |
2788 | in the current candidate tree are profitable to replace, assuming | |
2789 | MODE and SPEED. FIRST_DEP is the first dependent of the root of | |
2790 | the candidate tree. | |
2791 | ||
2792 | One slight limitation here is that we don't account for the possible | |
2793 | introduction of casts in some cases. See replace_one_candidate for | |
2794 | the cases where these are introduced. This should probably be cleaned | |
2795 | up sometime. */ | |
2796 | ||
2797 | static void | |
ef4bddc2 | 2798 | analyze_increments (slsr_cand_t first_dep, machine_mode mode, bool speed) |
88ca9ea1 BS |
2799 | { |
2800 | unsigned i; | |
2801 | ||
2802 | for (i = 0; i < incr_vec_len; i++) | |
2803 | { | |
27bcd47c | 2804 | HOST_WIDE_INT incr = incr_vec[i].incr.to_shwi (); |
88ca9ea1 BS |
2805 | |
2806 | /* If somehow this increment is bigger than a HWI, we won't | |
2807 | be optimizing candidates that use it. And if the increment | |
2808 | has a count of zero, nothing will be done with it. */ | |
807e902e | 2809 | if (!wi::fits_shwi_p (incr_vec[i].incr) || !incr_vec[i].count) |
88ca9ea1 BS |
2810 | incr_vec[i].cost = COST_INFINITE; |
2811 | ||
2812 | /* Increments of 0, 1, and -1 are always profitable to replace, | |
2813 | because they always replace a multiply or add with an add or | |
2814 | copy, and may cause one or more existing instructions to go | |
2815 | dead. Exception: -1 can't be assumed to be profitable for | |
2816 | pointer addition. */ | |
2817 | else if (incr == 0 | |
2818 | || incr == 1 | |
2819 | || (incr == -1 | |
2820 | && (gimple_assign_rhs_code (first_dep->cand_stmt) | |
2821 | != POINTER_PLUS_EXPR))) | |
2822 | incr_vec[i].cost = COST_NEUTRAL; | |
2823 | ||
6b5eea61 BS |
2824 | /* FORNOW: If we need to add an initializer, give up if a cast from |
2825 | the candidate's type to its stride's type can lose precision. | |
2826 | This could eventually be handled better by expressly retaining the | |
2827 | result of a cast to a wider type in the stride. Example: | |
2828 | ||
2829 | short int _1; | |
2830 | _2 = (int) _1; | |
2831 | _3 = _2 * 10; | |
2832 | _4 = x + _3; ADD: x + (10 * _1) : int | |
2833 | _5 = _2 * 15; | |
2834 | _6 = x + _3; ADD: x + (15 * _1) : int | |
2835 | ||
2836 | Right now replacing _6 would cause insertion of an initializer | |
2837 | of the form "short int T = _1 * 5;" followed by a cast to | |
2838 | int, which could overflow incorrectly. Had we recorded _2 or | |
2839 | (int)_1 as the stride, this wouldn't happen. However, doing | |
2840 | this breaks other opportunities, so this will require some | |
2841 | care. */ | |
2842 | else if (!incr_vec[i].initializer | |
2843 | && TREE_CODE (first_dep->stride) != INTEGER_CST | |
2844 | && !legal_cast_p_1 (first_dep->stride, | |
2845 | gimple_assign_lhs (first_dep->cand_stmt))) | |
2846 | ||
2847 | incr_vec[i].cost = COST_INFINITE; | |
2848 | ||
50251425 BS |
2849 | /* If we need to add an initializer, make sure we don't introduce |
2850 | a multiply by a pointer type, which can happen in certain cast | |
2851 | scenarios. FIXME: When cleaning up these cast issues, we can | |
2852 | afford to introduce the multiply provided we cast out to an | |
2853 | unsigned int of appropriate size. */ | |
2854 | else if (!incr_vec[i].initializer | |
2855 | && TREE_CODE (first_dep->stride) != INTEGER_CST | |
2856 | && POINTER_TYPE_P (TREE_TYPE (first_dep->stride))) | |
2857 | ||
2858 | incr_vec[i].cost = COST_INFINITE; | |
2859 | ||
88ca9ea1 BS |
2860 | /* For any other increment, if this is a multiply candidate, we |
2861 | must introduce a temporary T and initialize it with | |
2862 | T_0 = stride * increment. When optimizing for speed, walk the | |
2863 | candidate tree to calculate the best cost reduction along any | |
2864 | path; if it offsets the fixed cost of inserting the initializer, | |
2865 | replacing the increment is profitable. When optimizing for | |
2866 | size, instead calculate the total cost reduction from replacing | |
2867 | all candidates with this increment. */ | |
2868 | else if (first_dep->kind == CAND_MULT) | |
2869 | { | |
2870 | int cost = mult_by_coeff_cost (incr, mode, speed); | |
2871 | int repl_savings = mul_cost (speed, mode) - add_cost (speed, mode); | |
2872 | if (speed) | |
2873 | cost = lowest_cost_path (cost, repl_savings, first_dep, | |
9b92d12b | 2874 | incr_vec[i].incr, COUNT_PHIS); |
88ca9ea1 | 2875 | else |
9b92d12b BS |
2876 | cost -= total_savings (repl_savings, first_dep, incr_vec[i].incr, |
2877 | COUNT_PHIS); | |
88ca9ea1 BS |
2878 | |
2879 | incr_vec[i].cost = cost; | |
2880 | } | |
2881 | ||
2882 | /* If this is an add candidate, the initializer may already | |
2883 | exist, so only calculate the cost of the initializer if it | |
2884 | doesn't. We are replacing one add with another here, so the | |
2885 | known replacement savings is zero. We will account for removal | |
2886 | of dead instructions in lowest_cost_path or total_savings. */ | |
2887 | else | |
2888 | { | |
2889 | int cost = 0; | |
2890 | if (!incr_vec[i].initializer) | |
2891 | cost = mult_by_coeff_cost (incr, mode, speed); | |
2892 | ||
2893 | if (speed) | |
9b92d12b BS |
2894 | cost = lowest_cost_path (cost, 0, first_dep, incr_vec[i].incr, |
2895 | DONT_COUNT_PHIS); | |
88ca9ea1 | 2896 | else |
9b92d12b BS |
2897 | cost -= total_savings (0, first_dep, incr_vec[i].incr, |
2898 | DONT_COUNT_PHIS); | |
88ca9ea1 BS |
2899 | |
2900 | incr_vec[i].cost = cost; | |
2901 | } | |
2902 | } | |
2903 | } | |
2904 | ||
2905 | /* Return the nearest common dominator of BB1 and BB2. If the blocks | |
2906 | are identical, return the earlier of C1 and C2 in *WHERE. Otherwise, | |
2907 | if the NCD matches BB1, return C1 in *WHERE; if the NCD matches BB2, | |
2908 | return C2 in *WHERE; and if the NCD matches neither, return NULL in | |
2909 | *WHERE. Note: It is possible for one of C1 and C2 to be NULL. */ | |
2910 | ||
2911 | static basic_block | |
2912 | ncd_for_two_cands (basic_block bb1, basic_block bb2, | |
2913 | slsr_cand_t c1, slsr_cand_t c2, slsr_cand_t *where) | |
2914 | { | |
2915 | basic_block ncd; | |
2916 | ||
2917 | if (!bb1) | |
2918 | { | |
2919 | *where = c2; | |
2920 | return bb2; | |
2921 | } | |
2922 | ||
2923 | if (!bb2) | |
2924 | { | |
2925 | *where = c1; | |
2926 | return bb1; | |
2927 | } | |
2928 | ||
2929 | ncd = nearest_common_dominator (CDI_DOMINATORS, bb1, bb2); | |
2930 | ||
2931 | /* If both candidates are in the same block, the earlier | |
2932 | candidate wins. */ | |
2933 | if (bb1 == ncd && bb2 == ncd) | |
2934 | { | |
2935 | if (!c1 || (c2 && c2->cand_num < c1->cand_num)) | |
2936 | *where = c2; | |
2937 | else | |
2938 | *where = c1; | |
2939 | } | |
2940 | ||
2941 | /* Otherwise, if one of them produced a candidate in the | |
2942 | dominator, that one wins. */ | |
2943 | else if (bb1 == ncd) | |
2944 | *where = c1; | |
2945 | ||
2946 | else if (bb2 == ncd) | |
2947 | *where = c2; | |
2948 | ||
2949 | /* If neither matches the dominator, neither wins. */ | |
2950 | else | |
2951 | *where = NULL; | |
2952 | ||
2953 | return ncd; | |
2954 | } | |
2955 | ||
9b92d12b BS |
2956 | /* Consider all candidates that feed PHI. Find the nearest common |
2957 | dominator of those candidates requiring the given increment INCR. | |
2958 | Further find and return the nearest common dominator of this result | |
2959 | with block NCD. If the returned block contains one or more of the | |
2960 | candidates, return the earliest candidate in the block in *WHERE. */ | |
2961 | ||
2962 | static basic_block | |
538dd0b7 | 2963 | ncd_with_phi (slsr_cand_t c, const widest_int &incr, gphi *phi, |
9b92d12b BS |
2964 | basic_block ncd, slsr_cand_t *where) |
2965 | { | |
2966 | unsigned i; | |
2967 | slsr_cand_t basis = lookup_cand (c->basis); | |
2968 | slsr_cand_t phi_cand = base_cand_from_table (gimple_phi_result (phi)); | |
2969 | ||
2970 | for (i = 0; i < gimple_phi_num_args (phi); i++) | |
2971 | { | |
2972 | tree arg = gimple_phi_arg_def (phi, i); | |
2973 | ||
2974 | if (!operand_equal_p (arg, phi_cand->base_expr, 0)) | |
2975 | { | |
355fe088 | 2976 | gimple *arg_def = SSA_NAME_DEF_STMT (arg); |
9b92d12b BS |
2977 | |
2978 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
538dd0b7 DM |
2979 | ncd = ncd_with_phi (c, incr, as_a <gphi *> (arg_def), ncd, |
2980 | where); | |
9b92d12b BS |
2981 | else |
2982 | { | |
2983 | slsr_cand_t arg_cand = base_cand_from_table (arg); | |
807e902e | 2984 | widest_int diff = arg_cand->index - basis->index; |
1e386bb8 | 2985 | basic_block pred = gimple_phi_arg_edge (phi, i)->src; |
9b92d12b BS |
2986 | |
2987 | if ((incr == diff) || (!address_arithmetic_p && incr == -diff)) | |
1e386bb8 | 2988 | ncd = ncd_for_two_cands (ncd, pred, *where, NULL, where); |
9b92d12b BS |
2989 | } |
2990 | } | |
2991 | } | |
2992 | ||
2993 | return ncd; | |
2994 | } | |
2995 | ||
2996 | /* Consider the candidate C together with any candidates that feed | |
2997 | C's phi dependence (if any). Find and return the nearest common | |
2998 | dominator of those candidates requiring the given increment INCR. | |
2999 | If the returned block contains one or more of the candidates, | |
3000 | return the earliest candidate in the block in *WHERE. */ | |
3001 | ||
3002 | static basic_block | |
807e902e | 3003 | ncd_of_cand_and_phis (slsr_cand_t c, const widest_int &incr, slsr_cand_t *where) |
9b92d12b BS |
3004 | { |
3005 | basic_block ncd = NULL; | |
3006 | ||
3007 | if (cand_abs_increment (c) == incr) | |
3008 | { | |
3009 | ncd = gimple_bb (c->cand_stmt); | |
3010 | *where = c; | |
3011 | } | |
3012 | ||
3013 | if (phi_dependent_cand_p (c)) | |
538dd0b7 DM |
3014 | ncd = ncd_with_phi (c, incr, |
3015 | as_a <gphi *> (lookup_cand (c->def_phi)->cand_stmt), | |
9b92d12b BS |
3016 | ncd, where); |
3017 | ||
3018 | return ncd; | |
3019 | } | |
3020 | ||
88ca9ea1 BS |
3021 | /* Consider all candidates in the tree rooted at C for which INCR |
3022 | represents the required increment of C relative to its basis. | |
3023 | Find and return the basic block that most nearly dominates all | |
3024 | such candidates. If the returned block contains one or more of | |
3025 | the candidates, return the earliest candidate in the block in | |
3026 | *WHERE. */ | |
3027 | ||
3028 | static basic_block | |
807e902e | 3029 | nearest_common_dominator_for_cands (slsr_cand_t c, const widest_int &incr, |
88ca9ea1 BS |
3030 | slsr_cand_t *where) |
3031 | { | |
3032 | basic_block sib_ncd = NULL, dep_ncd = NULL, this_ncd = NULL, ncd; | |
3033 | slsr_cand_t sib_where = NULL, dep_where = NULL, this_where = NULL, new_where; | |
88ca9ea1 BS |
3034 | |
3035 | /* First find the NCD of all siblings and dependents. */ | |
3036 | if (c->sibling) | |
3037 | sib_ncd = nearest_common_dominator_for_cands (lookup_cand (c->sibling), | |
3038 | incr, &sib_where); | |
3039 | if (c->dependent) | |
3040 | dep_ncd = nearest_common_dominator_for_cands (lookup_cand (c->dependent), | |
3041 | incr, &dep_where); | |
3042 | if (!sib_ncd && !dep_ncd) | |
3043 | { | |
3044 | new_where = NULL; | |
3045 | ncd = NULL; | |
3046 | } | |
3047 | else if (sib_ncd && !dep_ncd) | |
3048 | { | |
3049 | new_where = sib_where; | |
3050 | ncd = sib_ncd; | |
3051 | } | |
3052 | else if (dep_ncd && !sib_ncd) | |
3053 | { | |
3054 | new_where = dep_where; | |
3055 | ncd = dep_ncd; | |
3056 | } | |
3057 | else | |
3058 | ncd = ncd_for_two_cands (sib_ncd, dep_ncd, sib_where, | |
3059 | dep_where, &new_where); | |
3060 | ||
3061 | /* If the candidate's increment doesn't match the one we're interested | |
9b92d12b BS |
3062 | in (and nor do any increments for feeding defs of a phi-dependence), |
3063 | then the result depends only on siblings and dependents. */ | |
3064 | this_ncd = ncd_of_cand_and_phis (c, incr, &this_where); | |
88ca9ea1 | 3065 | |
9b92d12b | 3066 | if (!this_ncd || cand_already_replaced (c)) |
88ca9ea1 BS |
3067 | { |
3068 | *where = new_where; | |
3069 | return ncd; | |
3070 | } | |
3071 | ||
3072 | /* Otherwise, compare this candidate with the result from all siblings | |
3073 | and dependents. */ | |
88ca9ea1 BS |
3074 | ncd = ncd_for_two_cands (ncd, this_ncd, new_where, this_where, where); |
3075 | ||
3076 | return ncd; | |
3077 | } | |
3078 | ||
3079 | /* Return TRUE if the increment indexed by INDEX is profitable to replace. */ | |
3080 | ||
3081 | static inline bool | |
3082 | profitable_increment_p (unsigned index) | |
3083 | { | |
3084 | return (incr_vec[index].cost <= COST_NEUTRAL); | |
3085 | } | |
3086 | ||
3087 | /* For each profitable increment in the increment vector not equal to | |
3088 | 0 or 1 (or -1, for non-pointer arithmetic), find the nearest common | |
3089 | dominator of all statements in the candidate chain rooted at C | |
3090 | that require that increment, and insert an initializer | |
3091 | T_0 = stride * increment at that location. Record T_0 with the | |
3092 | increment record. */ | |
3093 | ||
3094 | static void | |
3095 | insert_initializers (slsr_cand_t c) | |
3096 | { | |
3097 | unsigned i; | |
88ca9ea1 BS |
3098 | |
3099 | for (i = 0; i < incr_vec_len; i++) | |
3100 | { | |
3101 | basic_block bb; | |
3102 | slsr_cand_t where = NULL; | |
538dd0b7 | 3103 | gassign *init_stmt; |
88ca9ea1 | 3104 | tree stride_type, new_name, incr_tree; |
807e902e | 3105 | widest_int incr = incr_vec[i].incr; |
88ca9ea1 BS |
3106 | |
3107 | if (!profitable_increment_p (i) | |
807e902e KZ |
3108 | || incr == 1 |
3109 | || (incr == -1 | |
88ca9ea1 | 3110 | && gimple_assign_rhs_code (c->cand_stmt) != POINTER_PLUS_EXPR) |
807e902e | 3111 | || incr == 0) |
88ca9ea1 BS |
3112 | continue; |
3113 | ||
3114 | /* We may have already identified an existing initializer that | |
3115 | will suffice. */ | |
3116 | if (incr_vec[i].initializer) | |
3117 | { | |
3118 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3119 | { | |
3120 | fputs ("Using existing initializer: ", dump_file); | |
3121 | print_gimple_stmt (dump_file, | |
3122 | SSA_NAME_DEF_STMT (incr_vec[i].initializer), | |
3123 | 0, 0); | |
3124 | } | |
3125 | continue; | |
3126 | } | |
3127 | ||
3128 | /* Find the block that most closely dominates all candidates | |
3129 | with this increment. If there is at least one candidate in | |
3130 | that block, the earliest one will be returned in WHERE. */ | |
3131 | bb = nearest_common_dominator_for_cands (c, incr, &where); | |
3132 | ||
3133 | /* Create a new SSA name to hold the initializer's value. */ | |
3134 | stride_type = TREE_TYPE (c->stride); | |
a7a7d10e | 3135 | new_name = make_temp_ssa_name (stride_type, NULL, "slsr"); |
88ca9ea1 BS |
3136 | incr_vec[i].initializer = new_name; |
3137 | ||
3138 | /* Create the initializer and insert it in the latest possible | |
3139 | dominating position. */ | |
807e902e | 3140 | incr_tree = wide_int_to_tree (stride_type, incr); |
0d0e4a03 JJ |
3141 | init_stmt = gimple_build_assign (new_name, MULT_EXPR, |
3142 | c->stride, incr_tree); | |
88ca9ea1 BS |
3143 | if (where) |
3144 | { | |
3145 | gimple_stmt_iterator gsi = gsi_for_stmt (where->cand_stmt); | |
3146 | gsi_insert_before (&gsi, init_stmt, GSI_SAME_STMT); | |
3147 | gimple_set_location (init_stmt, gimple_location (where->cand_stmt)); | |
3148 | } | |
3149 | else | |
3150 | { | |
3151 | gimple_stmt_iterator gsi = gsi_last_bb (bb); | |
355fe088 | 3152 | gimple *basis_stmt = lookup_cand (c->basis)->cand_stmt; |
88ca9ea1 BS |
3153 | |
3154 | if (!gsi_end_p (gsi) && is_ctrl_stmt (gsi_stmt (gsi))) | |
3155 | gsi_insert_before (&gsi, init_stmt, GSI_SAME_STMT); | |
3156 | else | |
3157 | gsi_insert_after (&gsi, init_stmt, GSI_SAME_STMT); | |
3158 | ||
3159 | gimple_set_location (init_stmt, gimple_location (basis_stmt)); | |
3160 | } | |
3161 | ||
3162 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3163 | { | |
3164 | fputs ("Inserting initializer: ", dump_file); | |
3165 | print_gimple_stmt (dump_file, init_stmt, 0, 0); | |
3166 | } | |
3167 | } | |
3168 | } | |
3169 | ||
9b92d12b BS |
3170 | /* Return TRUE iff all required increments for candidates feeding PHI |
3171 | are profitable to replace on behalf of candidate C. */ | |
3172 | ||
3173 | static bool | |
355fe088 | 3174 | all_phi_incrs_profitable (slsr_cand_t c, gimple *phi) |
9b92d12b BS |
3175 | { |
3176 | unsigned i; | |
3177 | slsr_cand_t basis = lookup_cand (c->basis); | |
3178 | slsr_cand_t phi_cand = base_cand_from_table (gimple_phi_result (phi)); | |
3179 | ||
3180 | for (i = 0; i < gimple_phi_num_args (phi); i++) | |
3181 | { | |
3182 | tree arg = gimple_phi_arg_def (phi, i); | |
3183 | ||
3184 | if (!operand_equal_p (arg, phi_cand->base_expr, 0)) | |
3185 | { | |
355fe088 | 3186 | gimple *arg_def = SSA_NAME_DEF_STMT (arg); |
9b92d12b BS |
3187 | |
3188 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
3189 | { | |
3190 | if (!all_phi_incrs_profitable (c, arg_def)) | |
3191 | return false; | |
3192 | } | |
3193 | else | |
3194 | { | |
7bf55a70 | 3195 | int j; |
9b92d12b | 3196 | slsr_cand_t arg_cand = base_cand_from_table (arg); |
807e902e | 3197 | widest_int increment = arg_cand->index - basis->index; |
9b92d12b | 3198 | |
807e902e | 3199 | if (!address_arithmetic_p && wi::neg_p (increment)) |
9b92d12b BS |
3200 | increment = -increment; |
3201 | ||
3202 | j = incr_vec_index (increment); | |
3203 | ||
3204 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3205 | { | |
3206 | fprintf (dump_file, " Conditional candidate %d, phi: ", | |
3207 | c->cand_num); | |
3208 | print_gimple_stmt (dump_file, phi, 0, 0); | |
3209 | fputs (" increment: ", dump_file); | |
807e902e | 3210 | print_decs (increment, dump_file); |
7bf55a70 BS |
3211 | if (j < 0) |
3212 | fprintf (dump_file, | |
3213 | "\n Not replaced; incr_vec overflow.\n"); | |
3214 | else { | |
3215 | fprintf (dump_file, "\n cost: %d\n", incr_vec[j].cost); | |
3216 | if (profitable_increment_p (j)) | |
3217 | fputs (" Replacing...\n", dump_file); | |
3218 | else | |
3219 | fputs (" Not replaced.\n", dump_file); | |
3220 | } | |
9b92d12b BS |
3221 | } |
3222 | ||
7bf55a70 | 3223 | if (j < 0 || !profitable_increment_p (j)) |
9b92d12b BS |
3224 | return false; |
3225 | } | |
3226 | } | |
3227 | } | |
3228 | ||
3229 | return true; | |
3230 | } | |
3231 | ||
88ca9ea1 BS |
3232 | /* Create a NOP_EXPR that copies FROM_EXPR into a new SSA name of |
3233 | type TO_TYPE, and insert it in front of the statement represented | |
3234 | by candidate C. Use *NEW_VAR to create the new SSA name. Return | |
3235 | the new SSA name. */ | |
3236 | ||
3237 | static tree | |
a7a7d10e | 3238 | introduce_cast_before_cand (slsr_cand_t c, tree to_type, tree from_expr) |
88ca9ea1 BS |
3239 | { |
3240 | tree cast_lhs; | |
538dd0b7 | 3241 | gassign *cast_stmt; |
88ca9ea1 BS |
3242 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); |
3243 | ||
a7a7d10e | 3244 | cast_lhs = make_temp_ssa_name (to_type, NULL, "slsr"); |
0d0e4a03 | 3245 | cast_stmt = gimple_build_assign (cast_lhs, NOP_EXPR, from_expr); |
88ca9ea1 BS |
3246 | gimple_set_location (cast_stmt, gimple_location (c->cand_stmt)); |
3247 | gsi_insert_before (&gsi, cast_stmt, GSI_SAME_STMT); | |
3248 | ||
3249 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3250 | { | |
3251 | fputs (" Inserting: ", dump_file); | |
3252 | print_gimple_stmt (dump_file, cast_stmt, 0, 0); | |
3253 | } | |
3254 | ||
3255 | return cast_lhs; | |
3256 | } | |
3257 | ||
3258 | /* Replace the RHS of the statement represented by candidate C with | |
3259 | NEW_CODE, NEW_RHS1, and NEW_RHS2, provided that to do so doesn't | |
3260 | leave C unchanged or just interchange its operands. The original | |
3261 | operation and operands are in OLD_CODE, OLD_RHS1, and OLD_RHS2. | |
3262 | If the replacement was made and we are doing a details dump, | |
3263 | return the revised statement, else NULL. */ | |
3264 | ||
355fe088 | 3265 | static gimple * |
88ca9ea1 BS |
3266 | replace_rhs_if_not_dup (enum tree_code new_code, tree new_rhs1, tree new_rhs2, |
3267 | enum tree_code old_code, tree old_rhs1, tree old_rhs2, | |
3268 | slsr_cand_t c) | |
3269 | { | |
3270 | if (new_code != old_code | |
3271 | || ((!operand_equal_p (new_rhs1, old_rhs1, 0) | |
3272 | || !operand_equal_p (new_rhs2, old_rhs2, 0)) | |
3273 | && (!operand_equal_p (new_rhs1, old_rhs2, 0) | |
3274 | || !operand_equal_p (new_rhs2, old_rhs1, 0)))) | |
3275 | { | |
3276 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
3277 | gimple_assign_set_rhs_with_ops (&gsi, new_code, new_rhs1, new_rhs2); | |
3278 | update_stmt (gsi_stmt (gsi)); | |
bb0d2039 | 3279 | c->cand_stmt = gsi_stmt (gsi); |
88ca9ea1 BS |
3280 | |
3281 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3282 | return gsi_stmt (gsi); | |
3283 | } | |
3284 | ||
3285 | else if (dump_file && (dump_flags & TDF_DETAILS)) | |
3286 | fputs (" (duplicate, not actually replacing)\n", dump_file); | |
3287 | ||
3288 | return NULL; | |
3289 | } | |
3290 | ||
3291 | /* Strength-reduce the statement represented by candidate C by replacing | |
3292 | it with an equivalent addition or subtraction. I is the index into | |
3293 | the increment vector identifying C's increment. NEW_VAR is used to | |
3294 | create a new SSA name if a cast needs to be introduced. BASIS_NAME | |
3295 | is the rhs1 to use in creating the add/subtract. */ | |
3296 | ||
3297 | static void | |
a7a7d10e | 3298 | replace_one_candidate (slsr_cand_t c, unsigned i, tree basis_name) |
88ca9ea1 | 3299 | { |
355fe088 | 3300 | gimple *stmt_to_print = NULL; |
88ca9ea1 BS |
3301 | tree orig_rhs1, orig_rhs2; |
3302 | tree rhs2; | |
3303 | enum tree_code orig_code, repl_code; | |
807e902e | 3304 | widest_int cand_incr; |
88ca9ea1 BS |
3305 | |
3306 | orig_code = gimple_assign_rhs_code (c->cand_stmt); | |
3307 | orig_rhs1 = gimple_assign_rhs1 (c->cand_stmt); | |
3308 | orig_rhs2 = gimple_assign_rhs2 (c->cand_stmt); | |
3309 | cand_incr = cand_increment (c); | |
3310 | ||
3311 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3312 | { | |
3313 | fputs ("Replacing: ", dump_file); | |
3314 | print_gimple_stmt (dump_file, c->cand_stmt, 0, 0); | |
3315 | stmt_to_print = c->cand_stmt; | |
3316 | } | |
3317 | ||
3318 | if (address_arithmetic_p) | |
3319 | repl_code = POINTER_PLUS_EXPR; | |
3320 | else | |
3321 | repl_code = PLUS_EXPR; | |
3322 | ||
3323 | /* If the increment has an initializer T_0, replace the candidate | |
3324 | statement with an add of the basis name and the initializer. */ | |
3325 | if (incr_vec[i].initializer) | |
3326 | { | |
3327 | tree init_type = TREE_TYPE (incr_vec[i].initializer); | |
3328 | tree orig_type = TREE_TYPE (orig_rhs2); | |
3329 | ||
3330 | if (types_compatible_p (orig_type, init_type)) | |
3331 | rhs2 = incr_vec[i].initializer; | |
3332 | else | |
3333 | rhs2 = introduce_cast_before_cand (c, orig_type, | |
a7a7d10e | 3334 | incr_vec[i].initializer); |
88ca9ea1 | 3335 | |
27bcd47c | 3336 | if (incr_vec[i].incr != cand_incr) |
88ca9ea1 BS |
3337 | { |
3338 | gcc_assert (repl_code == PLUS_EXPR); | |
3339 | repl_code = MINUS_EXPR; | |
3340 | } | |
3341 | ||
3342 | stmt_to_print = replace_rhs_if_not_dup (repl_code, basis_name, rhs2, | |
3343 | orig_code, orig_rhs1, orig_rhs2, | |
3344 | c); | |
3345 | } | |
3346 | ||
3347 | /* Otherwise, the increment is one of -1, 0, and 1. Replace | |
3348 | with a subtract of the stride from the basis name, a copy | |
3349 | from the basis name, or an add of the stride to the basis | |
3350 | name, respectively. It may be necessary to introduce a | |
3351 | cast (or reuse an existing cast). */ | |
807e902e | 3352 | else if (cand_incr == 1) |
88ca9ea1 BS |
3353 | { |
3354 | tree stride_type = TREE_TYPE (c->stride); | |
3355 | tree orig_type = TREE_TYPE (orig_rhs2); | |
3356 | ||
3357 | if (types_compatible_p (orig_type, stride_type)) | |
3358 | rhs2 = c->stride; | |
3359 | else | |
a7a7d10e | 3360 | rhs2 = introduce_cast_before_cand (c, orig_type, c->stride); |
88ca9ea1 BS |
3361 | |
3362 | stmt_to_print = replace_rhs_if_not_dup (repl_code, basis_name, rhs2, | |
3363 | orig_code, orig_rhs1, orig_rhs2, | |
3364 | c); | |
3365 | } | |
3366 | ||
807e902e | 3367 | else if (cand_incr == -1) |
88ca9ea1 BS |
3368 | { |
3369 | tree stride_type = TREE_TYPE (c->stride); | |
3370 | tree orig_type = TREE_TYPE (orig_rhs2); | |
3371 | gcc_assert (repl_code != POINTER_PLUS_EXPR); | |
3372 | ||
3373 | if (types_compatible_p (orig_type, stride_type)) | |
3374 | rhs2 = c->stride; | |
3375 | else | |
a7a7d10e | 3376 | rhs2 = introduce_cast_before_cand (c, orig_type, c->stride); |
88ca9ea1 BS |
3377 | |
3378 | if (orig_code != MINUS_EXPR | |
3379 | || !operand_equal_p (basis_name, orig_rhs1, 0) | |
3380 | || !operand_equal_p (rhs2, orig_rhs2, 0)) | |
3381 | { | |
3382 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
3383 | gimple_assign_set_rhs_with_ops (&gsi, MINUS_EXPR, basis_name, rhs2); | |
3384 | update_stmt (gsi_stmt (gsi)); | |
bb0d2039 | 3385 | c->cand_stmt = gsi_stmt (gsi); |
88ca9ea1 BS |
3386 | |
3387 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3388 | stmt_to_print = gsi_stmt (gsi); | |
3389 | } | |
3390 | else if (dump_file && (dump_flags & TDF_DETAILS)) | |
3391 | fputs (" (duplicate, not actually replacing)\n", dump_file); | |
3392 | } | |
3393 | ||
807e902e | 3394 | else if (cand_incr == 0) |
88ca9ea1 BS |
3395 | { |
3396 | tree lhs = gimple_assign_lhs (c->cand_stmt); | |
3397 | tree lhs_type = TREE_TYPE (lhs); | |
3398 | tree basis_type = TREE_TYPE (basis_name); | |
3399 | ||
3400 | if (types_compatible_p (lhs_type, basis_type)) | |
3401 | { | |
538dd0b7 | 3402 | gassign *copy_stmt = gimple_build_assign (lhs, basis_name); |
88ca9ea1 BS |
3403 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); |
3404 | gimple_set_location (copy_stmt, gimple_location (c->cand_stmt)); | |
3405 | gsi_replace (&gsi, copy_stmt, false); | |
0100cd3f | 3406 | c->cand_stmt = copy_stmt; |
88ca9ea1 BS |
3407 | |
3408 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3409 | stmt_to_print = copy_stmt; | |
3410 | } | |
3411 | else | |
3412 | { | |
3413 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
0d0e4a03 | 3414 | gassign *cast_stmt = gimple_build_assign (lhs, NOP_EXPR, basis_name); |
88ca9ea1 BS |
3415 | gimple_set_location (cast_stmt, gimple_location (c->cand_stmt)); |
3416 | gsi_replace (&gsi, cast_stmt, false); | |
0100cd3f | 3417 | c->cand_stmt = cast_stmt; |
88ca9ea1 BS |
3418 | |
3419 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3420 | stmt_to_print = cast_stmt; | |
3421 | } | |
3422 | } | |
3423 | else | |
3424 | gcc_unreachable (); | |
3425 | ||
3426 | if (dump_file && (dump_flags & TDF_DETAILS) && stmt_to_print) | |
3427 | { | |
3428 | fputs ("With: ", dump_file); | |
3429 | print_gimple_stmt (dump_file, stmt_to_print, 0, 0); | |
3430 | fputs ("\n", dump_file); | |
3431 | } | |
3432 | } | |
3433 | ||
3434 | /* For each candidate in the tree rooted at C, replace it with | |
3435 | an increment if such has been shown to be profitable. */ | |
3436 | ||
3437 | static void | |
3438 | replace_profitable_candidates (slsr_cand_t c) | |
3439 | { | |
3440 | if (!cand_already_replaced (c)) | |
3441 | { | |
807e902e | 3442 | widest_int increment = cand_abs_increment (c); |
88ca9ea1 | 3443 | enum tree_code orig_code = gimple_assign_rhs_code (c->cand_stmt); |
7bf55a70 | 3444 | int i; |
88ca9ea1 BS |
3445 | |
3446 | i = incr_vec_index (increment); | |
3447 | ||
3448 | /* Only process profitable increments. Nothing useful can be done | |
3449 | to a cast or copy. */ | |
7bf55a70 BS |
3450 | if (i >= 0 |
3451 | && profitable_increment_p (i) | |
88ca9ea1 | 3452 | && orig_code != MODIFY_EXPR |
d822570f | 3453 | && !CONVERT_EXPR_CODE_P (orig_code)) |
88ca9ea1 | 3454 | { |
9b92d12b BS |
3455 | if (phi_dependent_cand_p (c)) |
3456 | { | |
355fe088 | 3457 | gimple *phi = lookup_cand (c->def_phi)->cand_stmt; |
9b92d12b BS |
3458 | |
3459 | if (all_phi_incrs_profitable (c, phi)) | |
3460 | { | |
3461 | /* Look up the LHS SSA name from C's basis. This will be | |
3462 | the RHS1 of the adds we will introduce to create new | |
3463 | phi arguments. */ | |
3464 | slsr_cand_t basis = lookup_cand (c->basis); | |
3465 | tree basis_name = gimple_assign_lhs (basis->cand_stmt); | |
3466 | ||
3467 | /* Create a new phi statement that will represent C's true | |
3468 | basis after the transformation is complete. */ | |
3469 | location_t loc = gimple_location (c->cand_stmt); | |
3470 | tree name = create_phi_basis (c, phi, basis_name, | |
3471 | loc, UNKNOWN_STRIDE); | |
3472 | ||
3473 | /* Replace C with an add of the new basis phi and the | |
3474 | increment. */ | |
a7a7d10e | 3475 | replace_one_candidate (c, i, name); |
9b92d12b BS |
3476 | } |
3477 | } | |
3478 | else | |
3479 | { | |
3480 | slsr_cand_t basis = lookup_cand (c->basis); | |
3481 | tree basis_name = gimple_assign_lhs (basis->cand_stmt); | |
a7a7d10e | 3482 | replace_one_candidate (c, i, basis_name); |
9b92d12b | 3483 | } |
88ca9ea1 BS |
3484 | } |
3485 | } | |
3486 | ||
3487 | if (c->sibling) | |
3488 | replace_profitable_candidates (lookup_cand (c->sibling)); | |
3489 | ||
3490 | if (c->dependent) | |
3491 | replace_profitable_candidates (lookup_cand (c->dependent)); | |
3492 | } | |
3493 | \f | |
f9453c07 BS |
3494 | /* Analyze costs of related candidates in the candidate vector, |
3495 | and make beneficial replacements. */ | |
3496 | ||
3497 | static void | |
3498 | analyze_candidates_and_replace (void) | |
3499 | { | |
3500 | unsigned i; | |
3501 | slsr_cand_t c; | |
3502 | ||
3503 | /* Each candidate that has a null basis and a non-null | |
3504 | dependent is the root of a tree of related statements. | |
3505 | Analyze each tree to determine a subset of those | |
3506 | statements that can be replaced with maximum benefit. */ | |
9771b263 | 3507 | FOR_EACH_VEC_ELT (cand_vec, i, c) |
f9453c07 BS |
3508 | { |
3509 | slsr_cand_t first_dep; | |
3510 | ||
3511 | if (c->basis != 0 || c->dependent == 0) | |
3512 | continue; | |
3513 | ||
3514 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3515 | fprintf (dump_file, "\nProcessing dependency tree rooted at %d.\n", | |
3516 | c->cand_num); | |
3517 | ||
3518 | first_dep = lookup_cand (c->dependent); | |
3519 | ||
2749c8f6 BS |
3520 | /* If this is a chain of CAND_REFs, unconditionally replace |
3521 | each of them with a strength-reduced data reference. */ | |
3522 | if (c->kind == CAND_REF) | |
3523 | replace_refs (c); | |
3524 | ||
9b92d12b BS |
3525 | /* If the common stride of all related candidates is a known |
3526 | constant, each candidate without a phi-dependence can be | |
3527 | profitably replaced. Each replaces a multiply by a single | |
3528 | add, with the possibility that a feeding add also goes dead. | |
3529 | A candidate with a phi-dependence is replaced only if the | |
3530 | compensation code it requires is offset by the strength | |
3531 | reduction savings. */ | |
3532 | else if (TREE_CODE (c->stride) == INTEGER_CST) | |
3533 | replace_uncond_cands_and_profitable_phis (first_dep); | |
f9453c07 | 3534 | |
88ca9ea1 BS |
3535 | /* When the stride is an SSA name, it may still be profitable |
3536 | to replace some or all of the dependent candidates, depending | |
3537 | on whether the introduced increments can be reused, or are | |
3538 | less expensive to calculate than the replaced statements. */ | |
3539 | else | |
3540 | { | |
ef4bddc2 | 3541 | machine_mode mode; |
88ca9ea1 BS |
3542 | bool speed; |
3543 | ||
3544 | /* Determine whether we'll be generating pointer arithmetic | |
3545 | when replacing candidates. */ | |
3546 | address_arithmetic_p = (c->kind == CAND_ADD | |
99cababb | 3547 | && POINTER_TYPE_P (c->cand_type)); |
88ca9ea1 BS |
3548 | |
3549 | /* If all candidates have already been replaced under other | |
3550 | interpretations, nothing remains to be done. */ | |
4b847da9 | 3551 | if (!count_candidates (c)) |
88ca9ea1 BS |
3552 | continue; |
3553 | ||
3554 | /* Construct an array of increments for this candidate chain. */ | |
4b847da9 | 3555 | incr_vec = XNEWVEC (incr_info, MAX_INCR_VEC_LEN); |
88ca9ea1 BS |
3556 | incr_vec_len = 0; |
3557 | record_increments (c); | |
3558 | ||
3559 | /* Determine which increments are profitable to replace. */ | |
3560 | mode = TYPE_MODE (TREE_TYPE (gimple_assign_lhs (c->cand_stmt))); | |
3561 | speed = optimize_cands_for_speed_p (c); | |
3562 | analyze_increments (first_dep, mode, speed); | |
3563 | ||
3564 | /* Insert initializers of the form T_0 = stride * increment | |
3565 | for use in profitable replacements. */ | |
3566 | insert_initializers (first_dep); | |
3567 | dump_incr_vec (); | |
3568 | ||
3569 | /* Perform the replacements. */ | |
3570 | replace_profitable_candidates (first_dep); | |
3571 | free (incr_vec); | |
3572 | } | |
f9453c07 BS |
3573 | } |
3574 | } | |
3575 | ||
17795822 TS |
3576 | namespace { |
3577 | ||
3578 | const pass_data pass_data_strength_reduction = | |
be55bfe6 TS |
3579 | { |
3580 | GIMPLE_PASS, /* type */ | |
3581 | "slsr", /* name */ | |
3582 | OPTGROUP_NONE, /* optinfo_flags */ | |
be55bfe6 TS |
3583 | TV_GIMPLE_SLSR, /* tv_id */ |
3584 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
3585 | 0, /* properties_provided */ | |
3586 | 0, /* properties_destroyed */ | |
3587 | 0, /* todo_flags_start */ | |
3bea341f | 3588 | 0, /* todo_flags_finish */ |
be55bfe6 TS |
3589 | }; |
3590 | ||
17795822 | 3591 | class pass_strength_reduction : public gimple_opt_pass |
be55bfe6 TS |
3592 | { |
3593 | public: | |
3594 | pass_strength_reduction (gcc::context *ctxt) | |
3595 | : gimple_opt_pass (pass_data_strength_reduction, ctxt) | |
3596 | {} | |
3597 | ||
3598 | /* opt_pass methods: */ | |
3599 | virtual bool gate (function *) { return flag_tree_slsr; } | |
3600 | virtual unsigned int execute (function *); | |
3601 | ||
3602 | }; // class pass_strength_reduction | |
3603 | ||
3604 | unsigned | |
3605 | pass_strength_reduction::execute (function *fun) | |
f9453c07 | 3606 | { |
f9453c07 BS |
3607 | /* Create the obstack where candidates will reside. */ |
3608 | gcc_obstack_init (&cand_obstack); | |
3609 | ||
3610 | /* Allocate the candidate vector. */ | |
9771b263 | 3611 | cand_vec.create (128); |
f9453c07 BS |
3612 | |
3613 | /* Allocate the mapping from statements to candidate indices. */ | |
355fe088 | 3614 | stmt_cand_map = new hash_map<gimple *, slsr_cand_t>; |
f9453c07 BS |
3615 | |
3616 | /* Create the obstack where candidate chains will reside. */ | |
3617 | gcc_obstack_init (&chain_obstack); | |
3618 | ||
3cfd4469 | 3619 | /* Allocate the mapping from base expressions to candidate chains. */ |
c203e8a7 | 3620 | base_cand_map = new hash_table<cand_chain_hasher> (500); |
f9453c07 | 3621 | |
96d75a2c | 3622 | /* Allocate the mapping from bases to alternative bases. */ |
b787e7a2 | 3623 | alt_base_map = new hash_map<tree, tree>; |
96d75a2c | 3624 | |
f9453c07 BS |
3625 | /* Initialize the loop optimizer. We need to detect flow across |
3626 | back edges, and this gives us dominator information as well. */ | |
3627 | loop_optimizer_init (AVOID_CFG_MODIFICATIONS); | |
3628 | ||
f9453c07 BS |
3629 | /* Walk the CFG in predominator order looking for strength reduction |
3630 | candidates. */ | |
4d9192b5 | 3631 | find_candidates_dom_walker (CDI_DOMINATORS) |
be55bfe6 | 3632 | .walk (fun->cfg->x_entry_block_ptr); |
f9453c07 BS |
3633 | |
3634 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3635 | { | |
3636 | dump_cand_vec (); | |
3637 | dump_cand_chains (); | |
3638 | } | |
3639 | ||
b787e7a2 | 3640 | delete alt_base_map; |
96d75a2c YZ |
3641 | free_affine_expand_cache (&name_expansions); |
3642 | ||
f9453c07 BS |
3643 | /* Analyze costs and make appropriate replacements. */ |
3644 | analyze_candidates_and_replace (); | |
3645 | ||
f9453c07 | 3646 | loop_optimizer_finalize (); |
c203e8a7 TS |
3647 | delete base_cand_map; |
3648 | base_cand_map = NULL; | |
f9453c07 | 3649 | obstack_free (&chain_obstack, NULL); |
b787e7a2 | 3650 | delete stmt_cand_map; |
9771b263 | 3651 | cand_vec.release (); |
f9453c07 | 3652 | obstack_free (&cand_obstack, NULL); |
f9453c07 BS |
3653 | |
3654 | return 0; | |
3655 | } | |
3656 | ||
17795822 TS |
3657 | } // anon namespace |
3658 | ||
27a4cd48 DM |
3659 | gimple_opt_pass * |
3660 | make_pass_strength_reduction (gcc::context *ctxt) | |
3661 | { | |
3662 | return new pass_strength_reduction (ctxt); | |
3663 | } |