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f9453c07 | 1 | /* Straight-line strength reduction. |
23a5b65a | 2 | Copyright (C) 2012-2014 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" | |
39 | #include "tree.h" | |
2fb9a547 AM |
40 | #include "pointer-set.h" |
41 | #include "hash-table.h" | |
42 | #include "basic-block.h" | |
43 | #include "tree-ssa-alias.h" | |
44 | #include "internal-fn.h" | |
45 | #include "gimple-expr.h" | |
46 | #include "is-a.h" | |
18f429e2 | 47 | #include "gimple.h" |
5be5c238 | 48 | #include "gimple-iterator.h" |
18f429e2 | 49 | #include "gimplify-me.h" |
d8a2d370 DN |
50 | #include "stor-layout.h" |
51 | #include "expr.h" | |
f9453c07 | 52 | #include "tree-pass.h" |
f9453c07 | 53 | #include "cfgloop.h" |
f9453c07 | 54 | #include "gimple-pretty-print.h" |
442b4905 AM |
55 | #include "gimple-ssa.h" |
56 | #include "tree-cfg.h" | |
57 | #include "tree-phinodes.h" | |
58 | #include "ssa-iterators.h" | |
d8a2d370 | 59 | #include "stringpool.h" |
442b4905 | 60 | #include "tree-ssanames.h" |
f9453c07 | 61 | #include "domwalk.h" |
6dd8f4bb | 62 | #include "expmed.h" |
ccdbfe93 | 63 | #include "params.h" |
4484a35a | 64 | #include "tree-ssa-address.h" |
96d75a2c | 65 | #include "tree-affine.h" |
f9453c07 BS |
66 | \f |
67 | /* Information about a strength reduction candidate. Each statement | |
68 | in the candidate table represents an expression of one of the | |
69 | following forms (the special case of CAND_REF will be described | |
70 | later): | |
71 | ||
72 | (CAND_MULT) S1: X = (B + i) * S | |
73 | (CAND_ADD) S1: X = B + (i * S) | |
74 | ||
75 | Here X and B are SSA names, i is an integer constant, and S is | |
76 | either an SSA name or a constant. We call B the "base," i the | |
77 | "index", and S the "stride." | |
78 | ||
79 | Any statement S0 that dominates S1 and is of the form: | |
80 | ||
81 | (CAND_MULT) S0: Y = (B + i') * S | |
82 | (CAND_ADD) S0: Y = B + (i' * S) | |
83 | ||
84 | is called a "basis" for S1. In both cases, S1 may be replaced by | |
85 | ||
86 | S1': X = Y + (i - i') * S, | |
87 | ||
88 | where (i - i') * S is folded to the extent possible. | |
89 | ||
90 | All gimple statements are visited in dominator order, and each | |
91 | statement that may contribute to one of the forms of S1 above is | |
92 | given at least one entry in the candidate table. Such statements | |
93 | include addition, pointer addition, subtraction, multiplication, | |
94 | negation, copies, and nontrivial type casts. If a statement may | |
95 | represent more than one expression of the forms of S1 above, | |
96 | multiple "interpretations" are stored in the table and chained | |
97 | together. Examples: | |
98 | ||
99 | * An add of two SSA names may treat either operand as the base. | |
100 | * A multiply of two SSA names, likewise. | |
101 | * A copy or cast may be thought of as either a CAND_MULT with | |
102 | i = 0 and S = 1, or as a CAND_ADD with i = 0 or S = 0. | |
103 | ||
104 | Candidate records are allocated from an obstack. They are addressed | |
105 | both from a hash table keyed on S1, and from a vector of candidate | |
106 | pointers arranged in predominator order. | |
107 | ||
108 | Opportunity note | |
109 | ---------------- | |
110 | Currently we don't recognize: | |
111 | ||
112 | S0: Y = (S * i') - B | |
113 | S1: X = (S * i) - B | |
114 | ||
115 | as a strength reduction opportunity, even though this S1 would | |
116 | also be replaceable by the S1' above. This can be added if it | |
2749c8f6 BS |
117 | comes up in practice. |
118 | ||
119 | Strength reduction in addressing | |
120 | -------------------------------- | |
121 | There is another kind of candidate known as CAND_REF. A CAND_REF | |
122 | describes a statement containing a memory reference having | |
123 | complex addressing that might benefit from strength reduction. | |
124 | Specifically, we are interested in references for which | |
125 | get_inner_reference returns a base address, offset, and bitpos as | |
126 | follows: | |
127 | ||
128 | base: MEM_REF (T1, C1) | |
129 | offset: MULT_EXPR (PLUS_EXPR (T2, C2), C3) | |
130 | bitpos: C4 * BITS_PER_UNIT | |
131 | ||
132 | Here T1 and T2 are arbitrary trees, and C1, C2, C3, C4 are | |
133 | arbitrary integer constants. Note that C2 may be zero, in which | |
134 | case the offset will be MULT_EXPR (T2, C3). | |
135 | ||
136 | When this pattern is recognized, the original memory reference | |
137 | can be replaced with: | |
138 | ||
139 | MEM_REF (POINTER_PLUS_EXPR (T1, MULT_EXPR (T2, C3)), | |
140 | C1 + (C2 * C3) + C4) | |
141 | ||
142 | which distributes the multiply to allow constant folding. When | |
143 | two or more addressing expressions can be represented by MEM_REFs | |
144 | of this form, differing only in the constants C1, C2, and C4, | |
145 | making this substitution produces more efficient addressing during | |
146 | the RTL phases. When there are not at least two expressions with | |
147 | the same values of T1, T2, and C3, there is nothing to be gained | |
148 | by the replacement. | |
149 | ||
150 | Strength reduction of CAND_REFs uses the same infrastructure as | |
151 | that used by CAND_MULTs and CAND_ADDs. We record T1 in the base (B) | |
152 | field, MULT_EXPR (T2, C3) in the stride (S) field, and | |
153 | C1 + (C2 * C3) + C4 in the index (i) field. A basis for a CAND_REF | |
154 | is thus another CAND_REF with the same B and S values. When at | |
155 | least two CAND_REFs are chained together using the basis relation, | |
156 | each of them is replaced as above, resulting in improved code | |
9b92d12b BS |
157 | generation for addressing. |
158 | ||
159 | Conditional candidates | |
160 | ====================== | |
161 | ||
162 | Conditional candidates are best illustrated with an example. | |
163 | Consider the code sequence: | |
164 | ||
165 | (1) x_0 = ...; | |
166 | (2) a_0 = x_0 * 5; MULT (B: x_0; i: 0; S: 5) | |
167 | if (...) | |
168 | (3) x_1 = x_0 + 1; ADD (B: x_0, i: 1; S: 1) | |
169 | (4) x_2 = PHI <x_0, x_1>; PHI (B: x_0, i: 0, S: 1) | |
170 | (5) x_3 = x_2 + 1; ADD (B: x_2, i: 1, S: 1) | |
171 | (6) a_1 = x_3 * 5; MULT (B: x_2, i: 1; S: 5) | |
172 | ||
173 | Here strength reduction is complicated by the uncertain value of x_2. | |
174 | A legitimate transformation is: | |
175 | ||
176 | (1) x_0 = ...; | |
177 | (2) a_0 = x_0 * 5; | |
178 | if (...) | |
179 | { | |
180 | (3) [x_1 = x_0 + 1;] | |
181 | (3a) t_1 = a_0 + 5; | |
182 | } | |
183 | (4) [x_2 = PHI <x_0, x_1>;] | |
184 | (4a) t_2 = PHI <a_0, t_1>; | |
185 | (5) [x_3 = x_2 + 1;] | |
186 | (6r) a_1 = t_2 + 5; | |
187 | ||
188 | where the bracketed instructions may go dead. | |
189 | ||
190 | To recognize this opportunity, we have to observe that statement (6) | |
191 | has a "hidden basis" (2). The hidden basis is unlike a normal basis | |
192 | in that the statement and the hidden basis have different base SSA | |
193 | names (x_2 and x_0, respectively). The relationship is established | |
194 | when a statement's base name (x_2) is defined by a phi statement (4), | |
195 | each argument of which (x_0, x_1) has an identical "derived base name." | |
196 | If the argument is defined by a candidate (as x_1 is by (3)) that is a | |
197 | CAND_ADD having a stride of 1, the derived base name of the argument is | |
198 | the base name of the candidate (x_0). Otherwise, the argument itself | |
199 | is its derived base name (as is the case with argument x_0). | |
200 | ||
201 | The hidden basis for statement (6) is the nearest dominating candidate | |
202 | whose base name is the derived base name (x_0) of the feeding phi (4), | |
203 | and whose stride is identical to that of the statement. We can then | |
204 | create the new "phi basis" (4a) and feeding adds along incoming arcs (3a), | |
205 | allowing the final replacement of (6) by the strength-reduced (6r). | |
206 | ||
207 | To facilitate this, a new kind of candidate (CAND_PHI) is introduced. | |
208 | A CAND_PHI is not a candidate for replacement, but is maintained in the | |
209 | candidate table to ease discovery of hidden bases. Any phi statement | |
210 | whose arguments share a common derived base name is entered into the | |
211 | table with the derived base name, an (arbitrary) index of zero, and a | |
212 | stride of 1. A statement with a hidden basis can then be detected by | |
213 | simply looking up its feeding phi definition in the candidate table, | |
214 | extracting the derived base name, and searching for a basis in the | |
215 | usual manner after substituting the derived base name. | |
216 | ||
217 | Note that the transformation is only valid when the original phi and | |
218 | the statements that define the phi's arguments are all at the same | |
219 | position in the loop hierarchy. */ | |
f9453c07 BS |
220 | |
221 | ||
222 | /* Index into the candidate vector, offset by 1. VECs are zero-based, | |
223 | while cand_idx's are one-based, with zero indicating null. */ | |
224 | typedef unsigned cand_idx; | |
225 | ||
226 | /* The kind of candidate. */ | |
227 | enum cand_kind | |
228 | { | |
229 | CAND_MULT, | |
2749c8f6 | 230 | CAND_ADD, |
9b92d12b BS |
231 | CAND_REF, |
232 | CAND_PHI | |
f9453c07 BS |
233 | }; |
234 | ||
235 | struct slsr_cand_d | |
236 | { | |
237 | /* The candidate statement S1. */ | |
238 | gimple cand_stmt; | |
239 | ||
3cfd4469 BS |
240 | /* The base expression B: often an SSA name, but not always. */ |
241 | tree base_expr; | |
f9453c07 BS |
242 | |
243 | /* The stride S. */ | |
244 | tree stride; | |
245 | ||
246 | /* The index constant i. */ | |
247 | double_int index; | |
248 | ||
3cfd4469 | 249 | /* The type of the candidate. This is normally the type of base_expr, |
f9453c07 | 250 | but casts may have occurred when combining feeding instructions. |
2749c8f6 BS |
251 | A candidate can only be a basis for candidates of the same final type. |
252 | (For CAND_REFs, this is the type to be used for operand 1 of the | |
253 | replacement MEM_REF.) */ | |
f9453c07 BS |
254 | tree cand_type; |
255 | ||
256 | /* The kind of candidate (CAND_MULT, etc.). */ | |
257 | enum cand_kind kind; | |
258 | ||
259 | /* Index of this candidate in the candidate vector. */ | |
260 | cand_idx cand_num; | |
261 | ||
262 | /* Index of the next candidate record for the same statement. | |
263 | A statement may be useful in more than one way (e.g., due to | |
264 | commutativity). So we can have multiple "interpretations" | |
265 | of a statement. */ | |
266 | cand_idx next_interp; | |
267 | ||
268 | /* Index of the basis statement S0, if any, in the candidate vector. */ | |
269 | cand_idx basis; | |
270 | ||
271 | /* First candidate for which this candidate is a basis, if one exists. */ | |
272 | cand_idx dependent; | |
273 | ||
274 | /* Next candidate having the same basis as this one. */ | |
275 | cand_idx sibling; | |
276 | ||
9b92d12b BS |
277 | /* If this is a conditional candidate, the CAND_PHI candidate |
278 | that defines the base SSA name B. */ | |
279 | cand_idx def_phi; | |
f9453c07 BS |
280 | |
281 | /* Savings that can be expected from eliminating dead code if this | |
282 | candidate is replaced. */ | |
283 | int dead_savings; | |
284 | }; | |
285 | ||
286 | typedef struct slsr_cand_d slsr_cand, *slsr_cand_t; | |
287 | typedef const struct slsr_cand_d *const_slsr_cand_t; | |
288 | ||
289 | /* Pointers to candidates are chained together as part of a mapping | |
3cfd4469 | 290 | from base expressions to the candidates that use them. */ |
f9453c07 BS |
291 | |
292 | struct cand_chain_d | |
293 | { | |
3cfd4469 BS |
294 | /* Base expression for the chain of candidates: often, but not |
295 | always, an SSA name. */ | |
296 | tree base_expr; | |
f9453c07 BS |
297 | |
298 | /* Pointer to a candidate. */ | |
299 | slsr_cand_t cand; | |
300 | ||
301 | /* Chain pointer. */ | |
302 | struct cand_chain_d *next; | |
303 | ||
304 | }; | |
305 | ||
306 | typedef struct cand_chain_d cand_chain, *cand_chain_t; | |
307 | typedef const struct cand_chain_d *const_cand_chain_t; | |
308 | ||
88ca9ea1 BS |
309 | /* Information about a unique "increment" associated with candidates |
310 | having an SSA name for a stride. An increment is the difference | |
311 | between the index of the candidate and the index of its basis, | |
312 | i.e., (i - i') as discussed in the module commentary. | |
313 | ||
314 | When we are not going to generate address arithmetic we treat | |
315 | increments that differ only in sign as the same, allowing sharing | |
316 | of the cost of initializers. The absolute value of the increment | |
317 | is stored in the incr_info. */ | |
318 | ||
319 | struct incr_info_d | |
320 | { | |
321 | /* The increment that relates a candidate to its basis. */ | |
322 | double_int incr; | |
323 | ||
324 | /* How many times the increment occurs in the candidate tree. */ | |
325 | unsigned count; | |
326 | ||
327 | /* Cost of replacing candidates using this increment. Negative and | |
328 | zero costs indicate replacement should be performed. */ | |
329 | int cost; | |
330 | ||
331 | /* If this increment is profitable but is not -1, 0, or 1, it requires | |
332 | an initializer T_0 = stride * incr to be found or introduced in the | |
333 | nearest common dominator of all candidates. This field holds T_0 | |
334 | for subsequent use. */ | |
335 | tree initializer; | |
336 | ||
337 | /* If the initializer was found to already exist, this is the block | |
338 | where it was found. */ | |
339 | basic_block init_bb; | |
340 | }; | |
341 | ||
342 | typedef struct incr_info_d incr_info, *incr_info_t; | |
343 | ||
f9453c07 BS |
344 | /* Candidates are maintained in a vector. If candidate X dominates |
345 | candidate Y, then X appears before Y in the vector; but the | |
346 | converse does not necessarily hold. */ | |
9771b263 | 347 | static vec<slsr_cand_t> cand_vec; |
f9453c07 BS |
348 | |
349 | enum cost_consts | |
350 | { | |
351 | COST_NEUTRAL = 0, | |
352 | COST_INFINITE = 1000 | |
353 | }; | |
354 | ||
9b92d12b BS |
355 | enum stride_status |
356 | { | |
357 | UNKNOWN_STRIDE = 0, | |
358 | KNOWN_STRIDE = 1 | |
359 | }; | |
360 | ||
361 | enum phi_adjust_status | |
362 | { | |
363 | NOT_PHI_ADJUST = 0, | |
364 | PHI_ADJUST = 1 | |
365 | }; | |
366 | ||
367 | enum count_phis_status | |
368 | { | |
369 | DONT_COUNT_PHIS = 0, | |
370 | COUNT_PHIS = 1 | |
371 | }; | |
372 | ||
f9453c07 BS |
373 | /* Pointer map embodying a mapping from statements to candidates. */ |
374 | static struct pointer_map_t *stmt_cand_map; | |
375 | ||
376 | /* Obstack for candidates. */ | |
377 | static struct obstack cand_obstack; | |
378 | ||
f9453c07 BS |
379 | /* Obstack for candidate chains. */ |
380 | static struct obstack chain_obstack; | |
88ca9ea1 BS |
381 | |
382 | /* An array INCR_VEC of incr_infos is used during analysis of related | |
383 | candidates having an SSA name for a stride. INCR_VEC_LEN describes | |
7bf55a70 BS |
384 | its current length. MAX_INCR_VEC_LEN is used to avoid costly |
385 | pathological cases. */ | |
88ca9ea1 BS |
386 | static incr_info_t incr_vec; |
387 | static unsigned incr_vec_len; | |
7bf55a70 | 388 | const int MAX_INCR_VEC_LEN = 16; |
88ca9ea1 BS |
389 | |
390 | /* For a chain of candidates with unknown stride, indicates whether or not | |
391 | we must generate pointer arithmetic when replacing statements. */ | |
392 | static bool address_arithmetic_p; | |
9b92d12b BS |
393 | |
394 | /* Forward function declarations. */ | |
395 | static slsr_cand_t base_cand_from_table (tree); | |
a7a7d10e | 396 | static tree introduce_cast_before_cand (slsr_cand_t, tree, tree); |
0916f876 | 397 | static bool legal_cast_p_1 (tree, tree); |
f9453c07 BS |
398 | \f |
399 | /* Produce a pointer to the IDX'th candidate in the candidate vector. */ | |
400 | ||
401 | static slsr_cand_t | |
402 | lookup_cand (cand_idx idx) | |
403 | { | |
9771b263 | 404 | return cand_vec[idx - 1]; |
f9453c07 BS |
405 | } |
406 | ||
4a8fb1a1 | 407 | /* Helper for hashing a candidate chain header. */ |
2749c8f6 | 408 | |
4a8fb1a1 | 409 | struct cand_chain_hasher : typed_noop_remove <cand_chain> |
2749c8f6 | 410 | { |
4a8fb1a1 LC |
411 | typedef cand_chain value_type; |
412 | typedef cand_chain compare_type; | |
413 | static inline hashval_t hash (const value_type *); | |
414 | static inline bool equal (const value_type *, const compare_type *); | |
415 | }; | |
2749c8f6 | 416 | |
4a8fb1a1 LC |
417 | inline hashval_t |
418 | cand_chain_hasher::hash (const value_type *p) | |
2749c8f6 | 419 | { |
4a8fb1a1 LC |
420 | tree base_expr = p->base_expr; |
421 | return iterative_hash_expr (base_expr, 0); | |
2749c8f6 BS |
422 | } |
423 | ||
4a8fb1a1 LC |
424 | inline bool |
425 | cand_chain_hasher::equal (const value_type *chain1, const compare_type *chain2) | |
2749c8f6 | 426 | { |
3cfd4469 | 427 | return operand_equal_p (chain1->base_expr, chain2->base_expr, 0); |
2749c8f6 | 428 | } |
4a8fb1a1 LC |
429 | |
430 | /* Hash table embodying a mapping from base exprs to chains of candidates. */ | |
431 | static hash_table <cand_chain_hasher> base_cand_map; | |
2749c8f6 | 432 | \f |
96d75a2c YZ |
433 | /* Pointer map used by tree_to_aff_combination_expand. */ |
434 | static struct pointer_map_t *name_expansions; | |
435 | /* Pointer map embodying a mapping from bases to alternative bases. */ | |
436 | static struct pointer_map_t *alt_base_map; | |
437 | ||
438 | /* Given BASE, use the tree affine combiniation facilities to | |
439 | find the underlying tree expression for BASE, with any | |
8fde427f YZ |
440 | immediate offset excluded. |
441 | ||
442 | N.B. we should eliminate this backtracking with better forward | |
443 | analysis in a future release. */ | |
96d75a2c YZ |
444 | |
445 | static tree | |
446 | get_alternative_base (tree base) | |
447 | { | |
448 | tree *result = (tree *) pointer_map_contains (alt_base_map, base); | |
449 | ||
450 | if (result == NULL) | |
451 | { | |
452 | tree expr; | |
453 | aff_tree aff; | |
454 | ||
455 | tree_to_aff_combination_expand (base, TREE_TYPE (base), | |
456 | &aff, &name_expansions); | |
457 | aff.offset = tree_to_double_int (integer_zero_node); | |
458 | expr = aff_combination_to_tree (&aff); | |
459 | ||
460 | result = (tree *) pointer_map_insert (alt_base_map, base); | |
461 | gcc_assert (!*result); | |
462 | ||
463 | if (expr == base) | |
464 | *result = NULL; | |
465 | else | |
466 | *result = expr; | |
467 | } | |
468 | ||
469 | return *result; | |
470 | } | |
471 | ||
9b92d12b | 472 | /* Look in the candidate table for a CAND_PHI that defines BASE and |
8b28cf47 | 473 | return it if found; otherwise return NULL. */ |
f9453c07 | 474 | |
9b92d12b | 475 | static cand_idx |
8b28cf47 | 476 | find_phi_def (tree base) |
9b92d12b BS |
477 | { |
478 | slsr_cand_t c; | |
479 | ||
480 | if (TREE_CODE (base) != SSA_NAME) | |
481 | return 0; | |
29105868 | 482 | |
9b92d12b BS |
483 | c = base_cand_from_table (base); |
484 | ||
485 | if (!c || c->kind != CAND_PHI) | |
486 | return 0; | |
487 | ||
488 | return c->cand_num; | |
489 | } | |
490 | ||
491 | /* Helper routine for find_basis_for_candidate. May be called twice: | |
96d75a2c YZ |
492 | once for the candidate's base expr, and optionally again either for |
493 | the candidate's phi definition or for a CAND_REF's alternative base | |
494 | expression. */ | |
9b92d12b BS |
495 | |
496 | static slsr_cand_t | |
497 | find_basis_for_base_expr (slsr_cand_t c, tree base_expr) | |
f9453c07 | 498 | { |
2749c8f6 | 499 | cand_chain mapping_key; |
f9453c07 BS |
500 | cand_chain_t chain; |
501 | slsr_cand_t basis = NULL; | |
502 | ||
ccdbfe93 BS |
503 | // Limit potential of N^2 behavior for long candidate chains. |
504 | int iters = 0; | |
505 | int max_iters = PARAM_VALUE (PARAM_MAX_SLSR_CANDIDATE_SCAN); | |
506 | ||
9b92d12b | 507 | mapping_key.base_expr = base_expr; |
4a8fb1a1 | 508 | chain = base_cand_map.find (&mapping_key); |
f9453c07 | 509 | |
ccdbfe93 | 510 | for (; chain && iters < max_iters; chain = chain->next, ++iters) |
f9453c07 BS |
511 | { |
512 | slsr_cand_t one_basis = chain->cand; | |
513 | ||
514 | if (one_basis->kind != c->kind | |
69e1a1a3 | 515 | || one_basis->cand_stmt == c->cand_stmt |
f9453c07 BS |
516 | || !operand_equal_p (one_basis->stride, c->stride, 0) |
517 | || !types_compatible_p (one_basis->cand_type, c->cand_type) | |
518 | || !dominated_by_p (CDI_DOMINATORS, | |
519 | gimple_bb (c->cand_stmt), | |
520 | gimple_bb (one_basis->cand_stmt))) | |
521 | continue; | |
522 | ||
523 | if (!basis || basis->cand_num < one_basis->cand_num) | |
524 | basis = one_basis; | |
525 | } | |
526 | ||
9b92d12b BS |
527 | return basis; |
528 | } | |
529 | ||
530 | /* Use the base expr from candidate C to look for possible candidates | |
531 | that can serve as a basis for C. Each potential basis must also | |
532 | appear in a block that dominates the candidate statement and have | |
533 | the same stride and type. If more than one possible basis exists, | |
534 | the one with highest index in the vector is chosen; this will be | |
535 | the most immediately dominating basis. */ | |
536 | ||
537 | static int | |
538 | find_basis_for_candidate (slsr_cand_t c) | |
539 | { | |
540 | slsr_cand_t basis = find_basis_for_base_expr (c, c->base_expr); | |
541 | ||
542 | /* If a candidate doesn't have a basis using its base expression, | |
543 | it may have a basis hidden by one or more intervening phis. */ | |
544 | if (!basis && c->def_phi) | |
545 | { | |
546 | basic_block basis_bb, phi_bb; | |
547 | slsr_cand_t phi_cand = lookup_cand (c->def_phi); | |
548 | basis = find_basis_for_base_expr (c, phi_cand->base_expr); | |
549 | ||
550 | if (basis) | |
551 | { | |
552 | /* A hidden basis must dominate the phi-definition of the | |
553 | candidate's base name. */ | |
554 | phi_bb = gimple_bb (phi_cand->cand_stmt); | |
555 | basis_bb = gimple_bb (basis->cand_stmt); | |
556 | ||
557 | if (phi_bb == basis_bb | |
558 | || !dominated_by_p (CDI_DOMINATORS, phi_bb, basis_bb)) | |
559 | { | |
560 | basis = NULL; | |
561 | c->basis = 0; | |
562 | } | |
563 | ||
564 | /* If we found a hidden basis, estimate additional dead-code | |
565 | savings if the phi and its feeding statements can be removed. */ | |
566 | if (basis && has_single_use (gimple_phi_result (phi_cand->cand_stmt))) | |
567 | c->dead_savings += phi_cand->dead_savings; | |
568 | } | |
569 | } | |
570 | ||
8fde427f | 571 | if (flag_expensive_optimizations && !basis && c->kind == CAND_REF) |
96d75a2c YZ |
572 | { |
573 | tree alt_base_expr = get_alternative_base (c->base_expr); | |
574 | if (alt_base_expr) | |
575 | basis = find_basis_for_base_expr (c, alt_base_expr); | |
576 | } | |
577 | ||
f9453c07 BS |
578 | if (basis) |
579 | { | |
580 | c->sibling = basis->dependent; | |
581 | basis->dependent = c->cand_num; | |
582 | return basis->cand_num; | |
583 | } | |
584 | ||
585 | return 0; | |
586 | } | |
587 | ||
96d75a2c YZ |
588 | /* Record a mapping from BASE to C, indicating that C may potentially serve |
589 | as a basis using that base expression. BASE may be the same as | |
590 | C->BASE_EXPR; alternatively BASE can be a different tree that share the | |
591 | underlining expression of C->BASE_EXPR. */ | |
f9453c07 BS |
592 | |
593 | static void | |
96d75a2c | 594 | record_potential_basis (slsr_cand_t c, tree base) |
f9453c07 | 595 | { |
2749c8f6 | 596 | cand_chain_t node; |
4a8fb1a1 | 597 | cand_chain **slot; |
f9453c07 | 598 | |
96d75a2c YZ |
599 | gcc_assert (base); |
600 | ||
f9453c07 | 601 | node = (cand_chain_t) obstack_alloc (&chain_obstack, sizeof (cand_chain)); |
96d75a2c | 602 | node->base_expr = base; |
f9453c07 BS |
603 | node->cand = c; |
604 | node->next = NULL; | |
4a8fb1a1 | 605 | slot = base_cand_map.find_slot (node, INSERT); |
f9453c07 | 606 | |
2749c8f6 | 607 | if (*slot) |
f9453c07 | 608 | { |
2749c8f6 | 609 | cand_chain_t head = (cand_chain_t) (*slot); |
f9453c07 BS |
610 | node->next = head->next; |
611 | head->next = node; | |
612 | } | |
613 | else | |
2749c8f6 | 614 | *slot = node; |
f9453c07 BS |
615 | } |
616 | ||
617 | /* Allocate storage for a new candidate and initialize its fields. | |
96d75a2c YZ |
618 | Attempt to find a basis for the candidate. |
619 | ||
620 | For CAND_REF, an alternative base may also be recorded and used | |
621 | to find a basis. This helps cases where the expression hidden | |
622 | behind BASE (which is usually an SSA_NAME) has immediate offset, | |
623 | e.g. | |
624 | ||
625 | a2[i][j] = 1; | |
626 | a2[i + 20][j] = 2; */ | |
f9453c07 BS |
627 | |
628 | static slsr_cand_t | |
96d75a2c | 629 | alloc_cand_and_find_basis (enum cand_kind kind, gimple gs, tree base, |
f9453c07 BS |
630 | double_int index, tree stride, tree ctype, |
631 | unsigned savings) | |
632 | { | |
633 | slsr_cand_t c = (slsr_cand_t) obstack_alloc (&cand_obstack, | |
634 | sizeof (slsr_cand)); | |
635 | c->cand_stmt = gs; | |
3cfd4469 | 636 | c->base_expr = base; |
f9453c07 BS |
637 | c->stride = stride; |
638 | c->index = index; | |
639 | c->cand_type = ctype; | |
640 | c->kind = kind; | |
9771b263 | 641 | c->cand_num = cand_vec.length () + 1; |
f9453c07 BS |
642 | c->next_interp = 0; |
643 | c->dependent = 0; | |
644 | c->sibling = 0; | |
8b28cf47 | 645 | c->def_phi = kind == CAND_MULT ? find_phi_def (base) : 0; |
f9453c07 BS |
646 | c->dead_savings = savings; |
647 | ||
9771b263 | 648 | cand_vec.safe_push (c); |
9b92d12b BS |
649 | |
650 | if (kind == CAND_PHI) | |
651 | c->basis = 0; | |
652 | else | |
653 | c->basis = find_basis_for_candidate (c); | |
654 | ||
96d75a2c | 655 | record_potential_basis (c, base); |
8fde427f | 656 | if (flag_expensive_optimizations && kind == CAND_REF) |
96d75a2c YZ |
657 | { |
658 | tree alt_base = get_alternative_base (base); | |
659 | if (alt_base) | |
660 | record_potential_basis (c, alt_base); | |
661 | } | |
f9453c07 BS |
662 | |
663 | return c; | |
664 | } | |
665 | ||
666 | /* Determine the target cost of statement GS when compiling according | |
667 | to SPEED. */ | |
668 | ||
669 | static int | |
670 | stmt_cost (gimple gs, bool speed) | |
671 | { | |
672 | tree lhs, rhs1, rhs2; | |
673 | enum machine_mode lhs_mode; | |
674 | ||
675 | gcc_assert (is_gimple_assign (gs)); | |
676 | lhs = gimple_assign_lhs (gs); | |
677 | rhs1 = gimple_assign_rhs1 (gs); | |
678 | lhs_mode = TYPE_MODE (TREE_TYPE (lhs)); | |
679 | ||
680 | switch (gimple_assign_rhs_code (gs)) | |
681 | { | |
682 | case MULT_EXPR: | |
683 | rhs2 = gimple_assign_rhs2 (gs); | |
684 | ||
9541ffee | 685 | if (tree_fits_shwi_p (rhs2)) |
eb1ce453 | 686 | return mult_by_coeff_cost (tree_to_shwi (rhs2), lhs_mode, speed); |
f9453c07 BS |
687 | |
688 | gcc_assert (TREE_CODE (rhs1) != INTEGER_CST); | |
5322d07e | 689 | return mul_cost (speed, lhs_mode); |
f9453c07 BS |
690 | |
691 | case PLUS_EXPR: | |
692 | case POINTER_PLUS_EXPR: | |
693 | case MINUS_EXPR: | |
5322d07e | 694 | return add_cost (speed, lhs_mode); |
f9453c07 BS |
695 | |
696 | case NEGATE_EXPR: | |
5322d07e | 697 | return neg_cost (speed, lhs_mode); |
f9453c07 BS |
698 | |
699 | case NOP_EXPR: | |
6dd8f4bb | 700 | return convert_cost (lhs_mode, TYPE_MODE (TREE_TYPE (rhs1)), speed); |
f9453c07 BS |
701 | |
702 | /* Note that we don't assign costs to copies that in most cases | |
703 | will go away. */ | |
704 | default: | |
705 | ; | |
706 | } | |
707 | ||
708 | gcc_unreachable (); | |
709 | return 0; | |
710 | } | |
711 | ||
712 | /* Look up the defining statement for BASE_IN and return a pointer | |
713 | to its candidate in the candidate table, if any; otherwise NULL. | |
714 | Only CAND_ADD and CAND_MULT candidates are returned. */ | |
715 | ||
716 | static slsr_cand_t | |
717 | base_cand_from_table (tree base_in) | |
718 | { | |
719 | slsr_cand_t *result; | |
720 | ||
721 | gimple def = SSA_NAME_DEF_STMT (base_in); | |
722 | if (!def) | |
723 | return (slsr_cand_t) NULL; | |
724 | ||
725 | result = (slsr_cand_t *) pointer_map_contains (stmt_cand_map, def); | |
2749c8f6 BS |
726 | |
727 | if (result && (*result)->kind != CAND_REF) | |
728 | return *result; | |
f9453c07 | 729 | |
2749c8f6 | 730 | return (slsr_cand_t) NULL; |
f9453c07 BS |
731 | } |
732 | ||
733 | /* Add an entry to the statement-to-candidate mapping. */ | |
734 | ||
735 | static void | |
736 | add_cand_for_stmt (gimple gs, slsr_cand_t c) | |
737 | { | |
738 | void **slot = pointer_map_insert (stmt_cand_map, gs); | |
739 | gcc_assert (!*slot); | |
740 | *slot = c; | |
741 | } | |
742 | \f | |
9b92d12b BS |
743 | /* Given PHI which contains a phi statement, determine whether it |
744 | satisfies all the requirements of a phi candidate. If so, create | |
745 | a candidate. Note that a CAND_PHI never has a basis itself, but | |
746 | is used to help find a basis for subsequent candidates. */ | |
747 | ||
748 | static void | |
749 | slsr_process_phi (gimple phi, bool speed) | |
750 | { | |
751 | unsigned i; | |
752 | tree arg0_base = NULL_TREE, base_type; | |
753 | slsr_cand_t c; | |
754 | struct loop *cand_loop = gimple_bb (phi)->loop_father; | |
755 | unsigned savings = 0; | |
756 | ||
757 | /* A CAND_PHI requires each of its arguments to have the same | |
758 | derived base name. (See the module header commentary for a | |
759 | definition of derived base names.) Furthermore, all feeding | |
760 | definitions must be in the same position in the loop hierarchy | |
761 | as PHI. */ | |
762 | ||
763 | for (i = 0; i < gimple_phi_num_args (phi); i++) | |
764 | { | |
765 | slsr_cand_t arg_cand; | |
766 | tree arg = gimple_phi_arg_def (phi, i); | |
767 | tree derived_base_name = NULL_TREE; | |
768 | gimple arg_stmt = NULL; | |
769 | basic_block arg_bb = NULL; | |
770 | ||
771 | if (TREE_CODE (arg) != SSA_NAME) | |
772 | return; | |
773 | ||
774 | arg_cand = base_cand_from_table (arg); | |
775 | ||
776 | if (arg_cand) | |
777 | { | |
778 | while (arg_cand->kind != CAND_ADD && arg_cand->kind != CAND_PHI) | |
779 | { | |
780 | if (!arg_cand->next_interp) | |
781 | return; | |
782 | ||
783 | arg_cand = lookup_cand (arg_cand->next_interp); | |
784 | } | |
785 | ||
786 | if (!integer_onep (arg_cand->stride)) | |
787 | return; | |
788 | ||
789 | derived_base_name = arg_cand->base_expr; | |
790 | arg_stmt = arg_cand->cand_stmt; | |
791 | arg_bb = gimple_bb (arg_stmt); | |
792 | ||
793 | /* Gather potential dead code savings if the phi statement | |
794 | can be removed later on. */ | |
795 | if (has_single_use (arg)) | |
796 | { | |
797 | if (gimple_code (arg_stmt) == GIMPLE_PHI) | |
798 | savings += arg_cand->dead_savings; | |
799 | else | |
800 | savings += stmt_cost (arg_stmt, speed); | |
801 | } | |
802 | } | |
803 | else | |
804 | { | |
805 | derived_base_name = arg; | |
806 | ||
807 | if (SSA_NAME_IS_DEFAULT_DEF (arg)) | |
fefa31b5 | 808 | arg_bb = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
9b92d12b BS |
809 | else |
810 | gimple_bb (SSA_NAME_DEF_STMT (arg)); | |
811 | } | |
812 | ||
813 | if (!arg_bb || arg_bb->loop_father != cand_loop) | |
814 | return; | |
815 | ||
816 | if (i == 0) | |
817 | arg0_base = derived_base_name; | |
818 | else if (!operand_equal_p (derived_base_name, arg0_base, 0)) | |
819 | return; | |
820 | } | |
821 | ||
822 | /* Create the candidate. "alloc_cand_and_find_basis" is named | |
823 | misleadingly for this case, as no basis will be sought for a | |
824 | CAND_PHI. */ | |
825 | base_type = TREE_TYPE (arg0_base); | |
826 | ||
827 | c = alloc_cand_and_find_basis (CAND_PHI, phi, arg0_base, double_int_zero, | |
828 | integer_one_node, base_type, savings); | |
829 | ||
830 | /* Add the candidate to the statement-candidate mapping. */ | |
831 | add_cand_for_stmt (phi, c); | |
832 | } | |
833 | ||
c068654b BC |
834 | /* Given PBASE which is a pointer to tree, look up the defining |
835 | statement for it and check whether the candidate is in the | |
836 | form of: | |
837 | ||
838 | X = B + (1 * S), S is integer constant | |
839 | X = B + (i * S), S is integer one | |
840 | ||
841 | If so, set PBASE to the candidate's base_expr and return double | |
842 | int (i * S). | |
843 | Otherwise, just return double int zero. */ | |
844 | ||
845 | static double_int | |
846 | backtrace_base_for_ref (tree *pbase) | |
847 | { | |
848 | tree base_in = *pbase; | |
849 | slsr_cand_t base_cand; | |
850 | ||
851 | STRIP_NOPS (base_in); | |
0916f876 YZ |
852 | |
853 | /* Strip off widening conversion(s) to handle cases where | |
854 | e.g. 'B' is widened from an 'int' in order to calculate | |
855 | a 64-bit address. */ | |
856 | if (CONVERT_EXPR_P (base_in) | |
857 | && legal_cast_p_1 (base_in, TREE_OPERAND (base_in, 0))) | |
858 | base_in = get_unwidened (base_in, NULL_TREE); | |
859 | ||
c068654b BC |
860 | if (TREE_CODE (base_in) != SSA_NAME) |
861 | return tree_to_double_int (integer_zero_node); | |
862 | ||
863 | base_cand = base_cand_from_table (base_in); | |
864 | ||
865 | while (base_cand && base_cand->kind != CAND_PHI) | |
866 | { | |
867 | if (base_cand->kind == CAND_ADD | |
868 | && base_cand->index.is_one () | |
869 | && TREE_CODE (base_cand->stride) == INTEGER_CST) | |
870 | { | |
871 | /* X = B + (1 * S), S is integer constant. */ | |
872 | *pbase = base_cand->base_expr; | |
873 | return tree_to_double_int (base_cand->stride); | |
874 | } | |
875 | else if (base_cand->kind == CAND_ADD | |
876 | && TREE_CODE (base_cand->stride) == INTEGER_CST | |
877 | && integer_onep (base_cand->stride)) | |
1d2151c6 | 878 | { |
c068654b BC |
879 | /* X = B + (i * S), S is integer one. */ |
880 | *pbase = base_cand->base_expr; | |
881 | return base_cand->index; | |
882 | } | |
883 | ||
884 | if (base_cand->next_interp) | |
885 | base_cand = lookup_cand (base_cand->next_interp); | |
886 | else | |
887 | base_cand = NULL; | |
888 | } | |
889 | ||
890 | return tree_to_double_int (integer_zero_node); | |
891 | } | |
892 | ||
2749c8f6 BS |
893 | /* Look for the following pattern: |
894 | ||
895 | *PBASE: MEM_REF (T1, C1) | |
896 | ||
897 | *POFFSET: MULT_EXPR (T2, C3) [C2 is zero] | |
898 | or | |
899 | MULT_EXPR (PLUS_EXPR (T2, C2), C3) | |
900 | or | |
901 | MULT_EXPR (MINUS_EXPR (T2, -C2), C3) | |
902 | ||
903 | *PINDEX: C4 * BITS_PER_UNIT | |
904 | ||
905 | If not present, leave the input values unchanged and return FALSE. | |
906 | Otherwise, modify the input values as follows and return TRUE: | |
907 | ||
908 | *PBASE: T1 | |
909 | *POFFSET: MULT_EXPR (T2, C3) | |
c068654b BC |
910 | *PINDEX: C1 + (C2 * C3) + C4 |
911 | ||
912 | When T2 is recorded by a CAND_ADD in the form of (T2' + C5), it | |
913 | will be further restructured to: | |
914 | ||
915 | *PBASE: T1 | |
916 | *POFFSET: MULT_EXPR (T2', C3) | |
917 | *PINDEX: C1 + (C2 * C3) + C4 + (C5 * C3) */ | |
2749c8f6 BS |
918 | |
919 | static bool | |
920 | restructure_reference (tree *pbase, tree *poffset, double_int *pindex, | |
921 | tree *ptype) | |
922 | { | |
923 | tree base = *pbase, offset = *poffset; | |
924 | double_int index = *pindex; | |
27bcd47c | 925 | double_int bpu = double_int::from_uhwi (BITS_PER_UNIT); |
2749c8f6 | 926 | tree mult_op0, mult_op1, t1, t2, type; |
c068654b | 927 | double_int c1, c2, c3, c4, c5; |
2749c8f6 BS |
928 | |
929 | if (!base | |
930 | || !offset | |
931 | || TREE_CODE (base) != MEM_REF | |
932 | || TREE_CODE (offset) != MULT_EXPR | |
933 | || TREE_CODE (TREE_OPERAND (offset, 1)) != INTEGER_CST | |
27bcd47c | 934 | || !index.umod (bpu, FLOOR_MOD_EXPR).is_zero ()) |
2749c8f6 BS |
935 | return false; |
936 | ||
937 | t1 = TREE_OPERAND (base, 0); | |
938 | c1 = mem_ref_offset (base); | |
939 | type = TREE_TYPE (TREE_OPERAND (base, 1)); | |
940 | ||
941 | mult_op0 = TREE_OPERAND (offset, 0); | |
942 | mult_op1 = TREE_OPERAND (offset, 1); | |
943 | ||
944 | c3 = tree_to_double_int (mult_op1); | |
945 | ||
946 | if (TREE_CODE (mult_op0) == PLUS_EXPR) | |
947 | ||
948 | if (TREE_CODE (TREE_OPERAND (mult_op0, 1)) == INTEGER_CST) | |
949 | { | |
950 | t2 = TREE_OPERAND (mult_op0, 0); | |
951 | c2 = tree_to_double_int (TREE_OPERAND (mult_op0, 1)); | |
952 | } | |
953 | else | |
954 | return false; | |
955 | ||
956 | else if (TREE_CODE (mult_op0) == MINUS_EXPR) | |
957 | ||
958 | if (TREE_CODE (TREE_OPERAND (mult_op0, 1)) == INTEGER_CST) | |
959 | { | |
960 | t2 = TREE_OPERAND (mult_op0, 0); | |
27bcd47c | 961 | c2 = -tree_to_double_int (TREE_OPERAND (mult_op0, 1)); |
2749c8f6 BS |
962 | } |
963 | else | |
964 | return false; | |
965 | ||
966 | else | |
967 | { | |
968 | t2 = mult_op0; | |
969 | c2 = double_int_zero; | |
970 | } | |
971 | ||
27bcd47c | 972 | c4 = index.udiv (bpu, FLOOR_DIV_EXPR); |
c068654b | 973 | c5 = backtrace_base_for_ref (&t2); |
2749c8f6 BS |
974 | |
975 | *pbase = t1; | |
c068654b | 976 | *poffset = fold_build2 (MULT_EXPR, sizetype, fold_convert (sizetype, t2), |
2749c8f6 | 977 | double_int_to_tree (sizetype, c3)); |
c068654b | 978 | *pindex = c1 + c2 * c3 + c4 + c5 * c3; |
2749c8f6 BS |
979 | *ptype = type; |
980 | ||
981 | return true; | |
982 | } | |
983 | ||
984 | /* Given GS which contains a data reference, create a CAND_REF entry in | |
985 | the candidate table and attempt to find a basis. */ | |
986 | ||
987 | static void | |
988 | slsr_process_ref (gimple gs) | |
989 | { | |
990 | tree ref_expr, base, offset, type; | |
991 | HOST_WIDE_INT bitsize, bitpos; | |
992 | enum machine_mode mode; | |
993 | int unsignedp, volatilep; | |
994 | double_int index; | |
995 | slsr_cand_t c; | |
996 | ||
997 | if (gimple_vdef (gs)) | |
998 | ref_expr = gimple_assign_lhs (gs); | |
999 | else | |
1000 | ref_expr = gimple_assign_rhs1 (gs); | |
1001 | ||
1002 | if (!handled_component_p (ref_expr) | |
1003 | || TREE_CODE (ref_expr) == BIT_FIELD_REF | |
1004 | || (TREE_CODE (ref_expr) == COMPONENT_REF | |
1005 | && DECL_BIT_FIELD (TREE_OPERAND (ref_expr, 1)))) | |
1006 | return; | |
1007 | ||
1008 | base = get_inner_reference (ref_expr, &bitsize, &bitpos, &offset, &mode, | |
b3ecff82 | 1009 | &unsignedp, &volatilep, false); |
27bcd47c | 1010 | index = double_int::from_uhwi (bitpos); |
2749c8f6 BS |
1011 | |
1012 | if (!restructure_reference (&base, &offset, &index, &type)) | |
1013 | return; | |
1014 | ||
1015 | c = alloc_cand_and_find_basis (CAND_REF, gs, base, index, offset, | |
1016 | type, 0); | |
1017 | ||
1018 | /* Add the candidate to the statement-candidate mapping. */ | |
1019 | add_cand_for_stmt (gs, c); | |
1020 | } | |
1021 | ||
f9453c07 BS |
1022 | /* Create a candidate entry for a statement GS, where GS multiplies |
1023 | two SSA names BASE_IN and STRIDE_IN. Propagate any known information | |
1024 | about the two SSA names into the new candidate. Return the new | |
1025 | candidate. */ | |
1026 | ||
1027 | static slsr_cand_t | |
1028 | create_mul_ssa_cand (gimple gs, tree base_in, tree stride_in, bool speed) | |
1029 | { | |
1030 | tree base = NULL_TREE, stride = NULL_TREE, ctype = NULL_TREE; | |
1031 | double_int index; | |
1032 | unsigned savings = 0; | |
1033 | slsr_cand_t c; | |
1034 | slsr_cand_t base_cand = base_cand_from_table (base_in); | |
1035 | ||
1036 | /* Look at all interpretations of the base candidate, if necessary, | |
1037 | to find information to propagate into this candidate. */ | |
9b92d12b | 1038 | while (base_cand && !base && base_cand->kind != CAND_PHI) |
f9453c07 BS |
1039 | { |
1040 | ||
9b92d12b | 1041 | if (base_cand->kind == CAND_MULT && integer_onep (base_cand->stride)) |
f9453c07 BS |
1042 | { |
1043 | /* Y = (B + i') * 1 | |
1044 | X = Y * Z | |
1045 | ================ | |
1046 | X = (B + i') * Z */ | |
3cfd4469 | 1047 | base = base_cand->base_expr; |
f9453c07 BS |
1048 | index = base_cand->index; |
1049 | stride = stride_in; | |
1050 | ctype = base_cand->cand_type; | |
1051 | if (has_single_use (base_in)) | |
1052 | savings = (base_cand->dead_savings | |
1053 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1054 | } | |
1055 | else if (base_cand->kind == CAND_ADD | |
1056 | && TREE_CODE (base_cand->stride) == INTEGER_CST) | |
1057 | { | |
1058 | /* Y = B + (i' * S), S constant | |
1059 | X = Y * Z | |
1060 | ============================ | |
1061 | X = B + ((i' * S) * Z) */ | |
3cfd4469 | 1062 | base = base_cand->base_expr; |
27bcd47c | 1063 | index = base_cand->index * tree_to_double_int (base_cand->stride); |
f9453c07 BS |
1064 | stride = stride_in; |
1065 | ctype = base_cand->cand_type; | |
1066 | if (has_single_use (base_in)) | |
1067 | savings = (base_cand->dead_savings | |
1068 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1069 | } | |
1070 | ||
1071 | if (base_cand->next_interp) | |
1072 | base_cand = lookup_cand (base_cand->next_interp); | |
1073 | else | |
1074 | base_cand = NULL; | |
1075 | } | |
1076 | ||
1077 | if (!base) | |
1078 | { | |
1079 | /* No interpretations had anything useful to propagate, so | |
1080 | produce X = (Y + 0) * Z. */ | |
1081 | base = base_in; | |
1082 | index = double_int_zero; | |
1083 | stride = stride_in; | |
b2ec94d4 | 1084 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1085 | } |
1086 | ||
1087 | c = alloc_cand_and_find_basis (CAND_MULT, gs, base, index, stride, | |
1088 | ctype, savings); | |
1089 | return c; | |
1090 | } | |
1091 | ||
1092 | /* Create a candidate entry for a statement GS, where GS multiplies | |
1093 | SSA name BASE_IN by constant STRIDE_IN. Propagate any known | |
1094 | information about BASE_IN into the new candidate. Return the new | |
1095 | candidate. */ | |
1096 | ||
1097 | static slsr_cand_t | |
1098 | create_mul_imm_cand (gimple gs, tree base_in, tree stride_in, bool speed) | |
1099 | { | |
1100 | tree base = NULL_TREE, stride = NULL_TREE, ctype = NULL_TREE; | |
1101 | double_int index, temp; | |
1102 | unsigned savings = 0; | |
1103 | slsr_cand_t c; | |
1104 | slsr_cand_t base_cand = base_cand_from_table (base_in); | |
1105 | ||
1106 | /* Look at all interpretations of the base candidate, if necessary, | |
1107 | to find information to propagate into this candidate. */ | |
9b92d12b | 1108 | while (base_cand && !base && base_cand->kind != CAND_PHI) |
f9453c07 BS |
1109 | { |
1110 | if (base_cand->kind == CAND_MULT | |
1111 | && TREE_CODE (base_cand->stride) == INTEGER_CST) | |
1112 | { | |
1113 | /* Y = (B + i') * S, S constant | |
1114 | X = Y * c | |
1115 | ============================ | |
1116 | X = (B + i') * (S * c) */ | |
27bcd47c LC |
1117 | temp = tree_to_double_int (base_cand->stride) |
1118 | * tree_to_double_int (stride_in); | |
61ba7329 BS |
1119 | if (double_int_fits_to_tree_p (TREE_TYPE (stride_in), temp)) |
1120 | { | |
1121 | base = base_cand->base_expr; | |
1122 | index = base_cand->index; | |
1123 | stride = double_int_to_tree (TREE_TYPE (stride_in), temp); | |
1124 | ctype = base_cand->cand_type; | |
1125 | if (has_single_use (base_in)) | |
1126 | savings = (base_cand->dead_savings | |
1127 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1128 | } | |
f9453c07 | 1129 | } |
9b92d12b | 1130 | else if (base_cand->kind == CAND_ADD && integer_onep (base_cand->stride)) |
f9453c07 BS |
1131 | { |
1132 | /* Y = B + (i' * 1) | |
1133 | X = Y * c | |
1134 | =========================== | |
1135 | X = (B + i') * c */ | |
3cfd4469 | 1136 | base = base_cand->base_expr; |
f9453c07 BS |
1137 | index = base_cand->index; |
1138 | stride = stride_in; | |
1139 | ctype = base_cand->cand_type; | |
1140 | if (has_single_use (base_in)) | |
1141 | savings = (base_cand->dead_savings | |
1142 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1143 | } | |
1144 | else if (base_cand->kind == CAND_ADD | |
27bcd47c | 1145 | && base_cand->index.is_one () |
f9453c07 BS |
1146 | && TREE_CODE (base_cand->stride) == INTEGER_CST) |
1147 | { | |
1148 | /* Y = B + (1 * S), S constant | |
1149 | X = Y * c | |
1150 | =========================== | |
1151 | X = (B + S) * c */ | |
3cfd4469 | 1152 | base = base_cand->base_expr; |
f9453c07 BS |
1153 | index = tree_to_double_int (base_cand->stride); |
1154 | stride = stride_in; | |
1155 | ctype = base_cand->cand_type; | |
1156 | if (has_single_use (base_in)) | |
1157 | savings = (base_cand->dead_savings | |
1158 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1159 | } | |
1160 | ||
1161 | if (base_cand->next_interp) | |
1162 | base_cand = lookup_cand (base_cand->next_interp); | |
1163 | else | |
1164 | base_cand = NULL; | |
1165 | } | |
1166 | ||
1167 | if (!base) | |
1168 | { | |
1169 | /* No interpretations had anything useful to propagate, so | |
1170 | produce X = (Y + 0) * c. */ | |
1171 | base = base_in; | |
1172 | index = double_int_zero; | |
1173 | stride = stride_in; | |
b2ec94d4 | 1174 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1175 | } |
1176 | ||
1177 | c = alloc_cand_and_find_basis (CAND_MULT, gs, base, index, stride, | |
1178 | ctype, savings); | |
1179 | return c; | |
1180 | } | |
1181 | ||
1182 | /* Given GS which is a multiply of scalar integers, make an appropriate | |
1183 | entry in the candidate table. If this is a multiply of two SSA names, | |
1184 | create two CAND_MULT interpretations and attempt to find a basis for | |
1185 | each of them. Otherwise, create a single CAND_MULT and attempt to | |
1186 | find a basis. */ | |
1187 | ||
1188 | static void | |
1189 | slsr_process_mul (gimple gs, tree rhs1, tree rhs2, bool speed) | |
1190 | { | |
1191 | slsr_cand_t c, c2; | |
1192 | ||
1193 | /* If this is a multiply of an SSA name with itself, it is highly | |
1194 | unlikely that we will get a strength reduction opportunity, so | |
1195 | don't record it as a candidate. This simplifies the logic for | |
1196 | finding a basis, so if this is removed that must be considered. */ | |
1197 | if (rhs1 == rhs2) | |
1198 | return; | |
1199 | ||
1200 | if (TREE_CODE (rhs2) == SSA_NAME) | |
1201 | { | |
1202 | /* Record an interpretation of this statement in the candidate table | |
3cfd4469 | 1203 | assuming RHS1 is the base expression and RHS2 is the stride. */ |
f9453c07 BS |
1204 | c = create_mul_ssa_cand (gs, rhs1, rhs2, speed); |
1205 | ||
1206 | /* Add the first interpretation to the statement-candidate mapping. */ | |
1207 | add_cand_for_stmt (gs, c); | |
1208 | ||
1209 | /* Record another interpretation of this statement assuming RHS1 | |
3cfd4469 | 1210 | is the stride and RHS2 is the base expression. */ |
f9453c07 BS |
1211 | c2 = create_mul_ssa_cand (gs, rhs2, rhs1, speed); |
1212 | c->next_interp = c2->cand_num; | |
1213 | } | |
1214 | else | |
1215 | { | |
1216 | /* Record an interpretation for the multiply-immediate. */ | |
1217 | c = create_mul_imm_cand (gs, rhs1, rhs2, speed); | |
1218 | ||
1219 | /* Add the interpretation to the statement-candidate mapping. */ | |
1220 | add_cand_for_stmt (gs, c); | |
1221 | } | |
1222 | } | |
1223 | ||
1224 | /* Create a candidate entry for a statement GS, where GS adds two | |
1225 | SSA names BASE_IN and ADDEND_IN if SUBTRACT_P is false, and | |
1226 | subtracts ADDEND_IN from BASE_IN otherwise. Propagate any known | |
1227 | information about the two SSA names into the new candidate. | |
1228 | Return the new candidate. */ | |
1229 | ||
1230 | static slsr_cand_t | |
1231 | create_add_ssa_cand (gimple gs, tree base_in, tree addend_in, | |
1232 | bool subtract_p, bool speed) | |
1233 | { | |
1234 | tree base = NULL_TREE, stride = NULL_TREE, ctype = NULL; | |
1235 | double_int index; | |
1236 | unsigned savings = 0; | |
1237 | slsr_cand_t c; | |
1238 | slsr_cand_t base_cand = base_cand_from_table (base_in); | |
1239 | slsr_cand_t addend_cand = base_cand_from_table (addend_in); | |
1240 | ||
1241 | /* The most useful transformation is a multiply-immediate feeding | |
1242 | an add or subtract. Look for that first. */ | |
9b92d12b | 1243 | while (addend_cand && !base && addend_cand->kind != CAND_PHI) |
f9453c07 BS |
1244 | { |
1245 | if (addend_cand->kind == CAND_MULT | |
27bcd47c | 1246 | && addend_cand->index.is_zero () |
f9453c07 BS |
1247 | && TREE_CODE (addend_cand->stride) == INTEGER_CST) |
1248 | { | |
1249 | /* Z = (B + 0) * S, S constant | |
1250 | X = Y +/- Z | |
1251 | =========================== | |
1252 | X = Y + ((+/-1 * S) * B) */ | |
1253 | base = base_in; | |
1254 | index = tree_to_double_int (addend_cand->stride); | |
1255 | if (subtract_p) | |
27bcd47c | 1256 | index = -index; |
3cfd4469 | 1257 | stride = addend_cand->base_expr; |
b2ec94d4 | 1258 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1259 | if (has_single_use (addend_in)) |
1260 | savings = (addend_cand->dead_savings | |
1261 | + stmt_cost (addend_cand->cand_stmt, speed)); | |
1262 | } | |
1263 | ||
1264 | if (addend_cand->next_interp) | |
1265 | addend_cand = lookup_cand (addend_cand->next_interp); | |
1266 | else | |
1267 | addend_cand = NULL; | |
1268 | } | |
1269 | ||
9b92d12b | 1270 | while (base_cand && !base && base_cand->kind != CAND_PHI) |
f9453c07 BS |
1271 | { |
1272 | if (base_cand->kind == CAND_ADD | |
27bcd47c | 1273 | && (base_cand->index.is_zero () |
f9453c07 BS |
1274 | || operand_equal_p (base_cand->stride, |
1275 | integer_zero_node, 0))) | |
1276 | { | |
1277 | /* Y = B + (i' * S), i' * S = 0 | |
1278 | X = Y +/- Z | |
1279 | ============================ | |
1280 | X = B + (+/-1 * Z) */ | |
3cfd4469 | 1281 | base = base_cand->base_expr; |
f9453c07 BS |
1282 | index = subtract_p ? double_int_minus_one : double_int_one; |
1283 | stride = addend_in; | |
1284 | ctype = base_cand->cand_type; | |
1285 | if (has_single_use (base_in)) | |
1286 | savings = (base_cand->dead_savings | |
1287 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1288 | } | |
1289 | else if (subtract_p) | |
1290 | { | |
1291 | slsr_cand_t subtrahend_cand = base_cand_from_table (addend_in); | |
1292 | ||
9b92d12b | 1293 | while (subtrahend_cand && !base && subtrahend_cand->kind != CAND_PHI) |
f9453c07 BS |
1294 | { |
1295 | if (subtrahend_cand->kind == CAND_MULT | |
27bcd47c | 1296 | && subtrahend_cand->index.is_zero () |
f9453c07 BS |
1297 | && TREE_CODE (subtrahend_cand->stride) == INTEGER_CST) |
1298 | { | |
1299 | /* Z = (B + 0) * S, S constant | |
1300 | X = Y - Z | |
1301 | =========================== | |
1302 | Value: X = Y + ((-1 * S) * B) */ | |
1303 | base = base_in; | |
1304 | index = tree_to_double_int (subtrahend_cand->stride); | |
27bcd47c | 1305 | index = -index; |
3cfd4469 | 1306 | stride = subtrahend_cand->base_expr; |
b2ec94d4 | 1307 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1308 | if (has_single_use (addend_in)) |
1309 | savings = (subtrahend_cand->dead_savings | |
1310 | + stmt_cost (subtrahend_cand->cand_stmt, speed)); | |
1311 | } | |
1312 | ||
1313 | if (subtrahend_cand->next_interp) | |
1314 | subtrahend_cand = lookup_cand (subtrahend_cand->next_interp); | |
1315 | else | |
1316 | subtrahend_cand = NULL; | |
1317 | } | |
1318 | } | |
1319 | ||
1320 | if (base_cand->next_interp) | |
1321 | base_cand = lookup_cand (base_cand->next_interp); | |
1322 | else | |
1323 | base_cand = NULL; | |
1324 | } | |
1325 | ||
1326 | if (!base) | |
1327 | { | |
1328 | /* No interpretations had anything useful to propagate, so | |
1329 | produce X = Y + (1 * Z). */ | |
1330 | base = base_in; | |
1331 | index = subtract_p ? double_int_minus_one : double_int_one; | |
1332 | stride = addend_in; | |
b2ec94d4 | 1333 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1334 | } |
1335 | ||
1336 | c = alloc_cand_and_find_basis (CAND_ADD, gs, base, index, stride, | |
1337 | ctype, savings); | |
1338 | return c; | |
1339 | } | |
1340 | ||
1341 | /* Create a candidate entry for a statement GS, where GS adds SSA | |
1342 | name BASE_IN to constant INDEX_IN. Propagate any known information | |
1343 | about BASE_IN into the new candidate. Return the new candidate. */ | |
1344 | ||
1345 | static slsr_cand_t | |
1346 | create_add_imm_cand (gimple gs, tree base_in, double_int index_in, bool speed) | |
1347 | { | |
1348 | enum cand_kind kind = CAND_ADD; | |
1349 | tree base = NULL_TREE, stride = NULL_TREE, ctype = NULL_TREE; | |
1350 | double_int index, multiple; | |
1351 | unsigned savings = 0; | |
1352 | slsr_cand_t c; | |
1353 | slsr_cand_t base_cand = base_cand_from_table (base_in); | |
1354 | ||
9b92d12b | 1355 | while (base_cand && !base && base_cand->kind != CAND_PHI) |
f9453c07 BS |
1356 | { |
1357 | bool unsigned_p = TYPE_UNSIGNED (TREE_TYPE (base_cand->stride)); | |
1358 | ||
1359 | if (TREE_CODE (base_cand->stride) == INTEGER_CST | |
27bcd47c LC |
1360 | && index_in.multiple_of (tree_to_double_int (base_cand->stride), |
1361 | unsigned_p, &multiple)) | |
f9453c07 BS |
1362 | { |
1363 | /* Y = (B + i') * S, S constant, c = kS for some integer k | |
1364 | X = Y + c | |
1365 | ============================ | |
1366 | X = (B + (i'+ k)) * S | |
1367 | OR | |
1368 | Y = B + (i' * S), S constant, c = kS for some integer k | |
1369 | X = Y + c | |
1370 | ============================ | |
1371 | X = (B + (i'+ k)) * S */ | |
1372 | kind = base_cand->kind; | |
3cfd4469 | 1373 | base = base_cand->base_expr; |
27bcd47c | 1374 | index = base_cand->index + multiple; |
f9453c07 BS |
1375 | stride = base_cand->stride; |
1376 | ctype = base_cand->cand_type; | |
1377 | if (has_single_use (base_in)) | |
1378 | savings = (base_cand->dead_savings | |
1379 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1380 | } | |
1381 | ||
1382 | if (base_cand->next_interp) | |
1383 | base_cand = lookup_cand (base_cand->next_interp); | |
1384 | else | |
1385 | base_cand = NULL; | |
1386 | } | |
1387 | ||
1388 | if (!base) | |
1389 | { | |
1390 | /* No interpretations had anything useful to propagate, so | |
1391 | produce X = Y + (c * 1). */ | |
1392 | kind = CAND_ADD; | |
1393 | base = base_in; | |
1394 | index = index_in; | |
1395 | stride = integer_one_node; | |
b2ec94d4 | 1396 | ctype = TREE_TYPE (base_in); |
f9453c07 BS |
1397 | } |
1398 | ||
1399 | c = alloc_cand_and_find_basis (kind, gs, base, index, stride, | |
1400 | ctype, savings); | |
1401 | return c; | |
1402 | } | |
1403 | ||
1404 | /* Given GS which is an add or subtract of scalar integers or pointers, | |
1405 | make at least one appropriate entry in the candidate table. */ | |
1406 | ||
1407 | static void | |
1408 | slsr_process_add (gimple gs, tree rhs1, tree rhs2, bool speed) | |
1409 | { | |
1410 | bool subtract_p = gimple_assign_rhs_code (gs) == MINUS_EXPR; | |
1411 | slsr_cand_t c = NULL, c2; | |
1412 | ||
1413 | if (TREE_CODE (rhs2) == SSA_NAME) | |
1414 | { | |
3cfd4469 | 1415 | /* First record an interpretation assuming RHS1 is the base expression |
f9453c07 BS |
1416 | and RHS2 is the stride. But it doesn't make sense for the |
1417 | stride to be a pointer, so don't record a candidate in that case. */ | |
b2ec94d4 | 1418 | if (!POINTER_TYPE_P (TREE_TYPE (rhs2))) |
f9453c07 BS |
1419 | { |
1420 | c = create_add_ssa_cand (gs, rhs1, rhs2, subtract_p, speed); | |
1421 | ||
1422 | /* Add the first interpretation to the statement-candidate | |
1423 | mapping. */ | |
1424 | add_cand_for_stmt (gs, c); | |
1425 | } | |
1426 | ||
1427 | /* If the two RHS operands are identical, or this is a subtract, | |
1428 | we're done. */ | |
1429 | if (operand_equal_p (rhs1, rhs2, 0) || subtract_p) | |
1430 | return; | |
1431 | ||
1432 | /* Otherwise, record another interpretation assuming RHS2 is the | |
3cfd4469 | 1433 | base expression and RHS1 is the stride, again provided that the |
f9453c07 | 1434 | stride is not a pointer. */ |
b2ec94d4 | 1435 | if (!POINTER_TYPE_P (TREE_TYPE (rhs1))) |
f9453c07 BS |
1436 | { |
1437 | c2 = create_add_ssa_cand (gs, rhs2, rhs1, false, speed); | |
1438 | if (c) | |
1439 | c->next_interp = c2->cand_num; | |
1440 | else | |
1441 | add_cand_for_stmt (gs, c2); | |
1442 | } | |
1443 | } | |
1444 | else | |
1445 | { | |
1446 | double_int index; | |
1447 | ||
1448 | /* Record an interpretation for the add-immediate. */ | |
1449 | index = tree_to_double_int (rhs2); | |
1450 | if (subtract_p) | |
27bcd47c | 1451 | index = -index; |
f9453c07 BS |
1452 | |
1453 | c = create_add_imm_cand (gs, rhs1, index, speed); | |
1454 | ||
1455 | /* Add the interpretation to the statement-candidate mapping. */ | |
1456 | add_cand_for_stmt (gs, c); | |
1457 | } | |
1458 | } | |
1459 | ||
1460 | /* Given GS which is a negate of a scalar integer, make an appropriate | |
1461 | entry in the candidate table. A negate is equivalent to a multiply | |
1462 | by -1. */ | |
1463 | ||
1464 | static void | |
1465 | slsr_process_neg (gimple gs, tree rhs1, bool speed) | |
1466 | { | |
1467 | /* Record a CAND_MULT interpretation for the multiply by -1. */ | |
1468 | slsr_cand_t c = create_mul_imm_cand (gs, rhs1, integer_minus_one_node, speed); | |
1469 | ||
1470 | /* Add the interpretation to the statement-candidate mapping. */ | |
1471 | add_cand_for_stmt (gs, c); | |
1472 | } | |
1473 | ||
6b5eea61 BS |
1474 | /* Help function for legal_cast_p, operating on two trees. Checks |
1475 | whether it's allowable to cast from RHS to LHS. See legal_cast_p | |
1476 | for more details. */ | |
1477 | ||
1478 | static bool | |
1479 | legal_cast_p_1 (tree lhs, tree rhs) | |
1480 | { | |
1481 | tree lhs_type, rhs_type; | |
1482 | unsigned lhs_size, rhs_size; | |
1483 | bool lhs_wraps, rhs_wraps; | |
1484 | ||
1485 | lhs_type = TREE_TYPE (lhs); | |
1486 | rhs_type = TREE_TYPE (rhs); | |
1487 | lhs_size = TYPE_PRECISION (lhs_type); | |
1488 | rhs_size = TYPE_PRECISION (rhs_type); | |
1489 | lhs_wraps = TYPE_OVERFLOW_WRAPS (lhs_type); | |
1490 | rhs_wraps = TYPE_OVERFLOW_WRAPS (rhs_type); | |
1491 | ||
1492 | if (lhs_size < rhs_size | |
1493 | || (rhs_wraps && !lhs_wraps) | |
1494 | || (rhs_wraps && lhs_wraps && rhs_size != lhs_size)) | |
1495 | return false; | |
1496 | ||
1497 | return true; | |
1498 | } | |
1499 | ||
f9453c07 BS |
1500 | /* Return TRUE if GS is a statement that defines an SSA name from |
1501 | a conversion and is legal for us to combine with an add and multiply | |
1502 | in the candidate table. For example, suppose we have: | |
1503 | ||
1504 | A = B + i; | |
1505 | C = (type) A; | |
1506 | D = C * S; | |
1507 | ||
1508 | Without the type-cast, we would create a CAND_MULT for D with base B, | |
1509 | index i, and stride S. We want to record this candidate only if it | |
1510 | is equivalent to apply the type cast following the multiply: | |
1511 | ||
1512 | A = B + i; | |
1513 | E = A * S; | |
1514 | D = (type) E; | |
1515 | ||
1516 | We will record the type with the candidate for D. This allows us | |
1517 | to use a similar previous candidate as a basis. If we have earlier seen | |
1518 | ||
1519 | A' = B + i'; | |
1520 | C' = (type) A'; | |
1521 | D' = C' * S; | |
1522 | ||
1523 | we can replace D with | |
1524 | ||
1525 | D = D' + (i - i') * S; | |
1526 | ||
1527 | But if moving the type-cast would change semantics, we mustn't do this. | |
1528 | ||
1529 | This is legitimate for casts from a non-wrapping integral type to | |
1530 | any integral type of the same or larger size. It is not legitimate | |
1531 | to convert a wrapping type to a non-wrapping type, or to a wrapping | |
1532 | type of a different size. I.e., with a wrapping type, we must | |
1533 | assume that the addition B + i could wrap, in which case performing | |
1534 | the multiply before or after one of the "illegal" type casts will | |
1535 | have different semantics. */ | |
1536 | ||
1537 | static bool | |
1538 | legal_cast_p (gimple gs, tree rhs) | |
1539 | { | |
f9453c07 BS |
1540 | if (!is_gimple_assign (gs) |
1541 | || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (gs))) | |
1542 | return false; | |
1543 | ||
6b5eea61 | 1544 | return legal_cast_p_1 (gimple_assign_lhs (gs), rhs); |
f9453c07 BS |
1545 | } |
1546 | ||
1547 | /* Given GS which is a cast to a scalar integer type, determine whether | |
1548 | the cast is legal for strength reduction. If so, make at least one | |
1549 | appropriate entry in the candidate table. */ | |
1550 | ||
1551 | static void | |
1552 | slsr_process_cast (gimple gs, tree rhs1, bool speed) | |
1553 | { | |
1554 | tree lhs, ctype; | |
1555 | slsr_cand_t base_cand, c, c2; | |
1556 | unsigned savings = 0; | |
1557 | ||
1558 | if (!legal_cast_p (gs, rhs1)) | |
1559 | return; | |
1560 | ||
1561 | lhs = gimple_assign_lhs (gs); | |
1562 | base_cand = base_cand_from_table (rhs1); | |
1563 | ctype = TREE_TYPE (lhs); | |
1564 | ||
9b92d12b | 1565 | if (base_cand && base_cand->kind != CAND_PHI) |
f9453c07 BS |
1566 | { |
1567 | while (base_cand) | |
1568 | { | |
1569 | /* Propagate all data from the base candidate except the type, | |
1570 | which comes from the cast, and the base candidate's cast, | |
1571 | which is no longer applicable. */ | |
1572 | if (has_single_use (rhs1)) | |
1573 | savings = (base_cand->dead_savings | |
1574 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1575 | ||
1576 | c = alloc_cand_and_find_basis (base_cand->kind, gs, | |
3cfd4469 | 1577 | base_cand->base_expr, |
f9453c07 BS |
1578 | base_cand->index, base_cand->stride, |
1579 | ctype, savings); | |
1580 | if (base_cand->next_interp) | |
1581 | base_cand = lookup_cand (base_cand->next_interp); | |
1582 | else | |
1583 | base_cand = NULL; | |
1584 | } | |
1585 | } | |
1586 | else | |
1587 | { | |
1588 | /* If nothing is known about the RHS, create fresh CAND_ADD and | |
1589 | CAND_MULT interpretations: | |
1590 | ||
1591 | X = Y + (0 * 1) | |
1592 | X = (Y + 0) * 1 | |
1593 | ||
1594 | The first of these is somewhat arbitrary, but the choice of | |
1595 | 1 for the stride simplifies the logic for propagating casts | |
1596 | into their uses. */ | |
1597 | c = alloc_cand_and_find_basis (CAND_ADD, gs, rhs1, double_int_zero, | |
1598 | integer_one_node, ctype, 0); | |
1599 | c2 = alloc_cand_and_find_basis (CAND_MULT, gs, rhs1, double_int_zero, | |
1600 | integer_one_node, ctype, 0); | |
1601 | c->next_interp = c2->cand_num; | |
1602 | } | |
1603 | ||
1604 | /* Add the first (or only) interpretation to the statement-candidate | |
1605 | mapping. */ | |
1606 | add_cand_for_stmt (gs, c); | |
1607 | } | |
1608 | ||
1609 | /* Given GS which is a copy of a scalar integer type, make at least one | |
1610 | appropriate entry in the candidate table. | |
1611 | ||
1612 | This interface is included for completeness, but is unnecessary | |
1613 | if this pass immediately follows a pass that performs copy | |
1614 | propagation, such as DOM. */ | |
1615 | ||
1616 | static void | |
1617 | slsr_process_copy (gimple gs, tree rhs1, bool speed) | |
1618 | { | |
1619 | slsr_cand_t base_cand, c, c2; | |
1620 | unsigned savings = 0; | |
1621 | ||
1622 | base_cand = base_cand_from_table (rhs1); | |
1623 | ||
9b92d12b | 1624 | if (base_cand && base_cand->kind != CAND_PHI) |
f9453c07 BS |
1625 | { |
1626 | while (base_cand) | |
1627 | { | |
1628 | /* Propagate all data from the base candidate. */ | |
1629 | if (has_single_use (rhs1)) | |
1630 | savings = (base_cand->dead_savings | |
1631 | + stmt_cost (base_cand->cand_stmt, speed)); | |
1632 | ||
1633 | c = alloc_cand_and_find_basis (base_cand->kind, gs, | |
3cfd4469 | 1634 | base_cand->base_expr, |
f9453c07 BS |
1635 | base_cand->index, base_cand->stride, |
1636 | base_cand->cand_type, savings); | |
1637 | if (base_cand->next_interp) | |
1638 | base_cand = lookup_cand (base_cand->next_interp); | |
1639 | else | |
1640 | base_cand = NULL; | |
1641 | } | |
1642 | } | |
1643 | else | |
1644 | { | |
1645 | /* If nothing is known about the RHS, create fresh CAND_ADD and | |
1646 | CAND_MULT interpretations: | |
1647 | ||
1648 | X = Y + (0 * 1) | |
1649 | X = (Y + 0) * 1 | |
1650 | ||
1651 | The first of these is somewhat arbitrary, but the choice of | |
1652 | 1 for the stride simplifies the logic for propagating casts | |
1653 | into their uses. */ | |
1654 | c = alloc_cand_and_find_basis (CAND_ADD, gs, rhs1, double_int_zero, | |
1655 | integer_one_node, TREE_TYPE (rhs1), 0); | |
1656 | c2 = alloc_cand_and_find_basis (CAND_MULT, gs, rhs1, double_int_zero, | |
1657 | integer_one_node, TREE_TYPE (rhs1), 0); | |
1658 | c->next_interp = c2->cand_num; | |
1659 | } | |
1660 | ||
1661 | /* Add the first (or only) interpretation to the statement-candidate | |
1662 | mapping. */ | |
1663 | add_cand_for_stmt (gs, c); | |
1664 | } | |
1665 | \f | |
4d9192b5 TS |
1666 | class find_candidates_dom_walker : public dom_walker |
1667 | { | |
1668 | public: | |
1669 | find_candidates_dom_walker (cdi_direction direction) | |
1670 | : dom_walker (direction) {} | |
1671 | virtual void before_dom_children (basic_block); | |
1672 | }; | |
1673 | ||
f9453c07 BS |
1674 | /* Find strength-reduction candidates in block BB. */ |
1675 | ||
4d9192b5 TS |
1676 | void |
1677 | find_candidates_dom_walker::before_dom_children (basic_block bb) | |
f9453c07 BS |
1678 | { |
1679 | bool speed = optimize_bb_for_speed_p (bb); | |
1680 | gimple_stmt_iterator gsi; | |
1681 | ||
9b92d12b BS |
1682 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
1683 | slsr_process_phi (gsi_stmt (gsi), speed); | |
1684 | ||
f9453c07 BS |
1685 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
1686 | { | |
1687 | gimple gs = gsi_stmt (gsi); | |
1688 | ||
2749c8f6 BS |
1689 | if (gimple_vuse (gs) && gimple_assign_single_p (gs)) |
1690 | slsr_process_ref (gs); | |
1691 | ||
1692 | else if (is_gimple_assign (gs) | |
1693 | && SCALAR_INT_MODE_P | |
1694 | (TYPE_MODE (TREE_TYPE (gimple_assign_lhs (gs))))) | |
f9453c07 BS |
1695 | { |
1696 | tree rhs1 = NULL_TREE, rhs2 = NULL_TREE; | |
1697 | ||
1698 | switch (gimple_assign_rhs_code (gs)) | |
1699 | { | |
1700 | case MULT_EXPR: | |
1701 | case PLUS_EXPR: | |
1702 | rhs1 = gimple_assign_rhs1 (gs); | |
1703 | rhs2 = gimple_assign_rhs2 (gs); | |
1704 | /* Should never happen, but currently some buggy situations | |
1705 | in earlier phases put constants in rhs1. */ | |
1706 | if (TREE_CODE (rhs1) != SSA_NAME) | |
1707 | continue; | |
1708 | break; | |
1709 | ||
1710 | /* Possible future opportunity: rhs1 of a ptr+ can be | |
1711 | an ADDR_EXPR. */ | |
1712 | case POINTER_PLUS_EXPR: | |
1713 | case MINUS_EXPR: | |
1714 | rhs2 = gimple_assign_rhs2 (gs); | |
1715 | /* Fall-through. */ | |
1716 | ||
1717 | case NOP_EXPR: | |
1718 | case MODIFY_EXPR: | |
1719 | case NEGATE_EXPR: | |
1720 | rhs1 = gimple_assign_rhs1 (gs); | |
1721 | if (TREE_CODE (rhs1) != SSA_NAME) | |
1722 | continue; | |
1723 | break; | |
1724 | ||
1725 | default: | |
1726 | ; | |
1727 | } | |
1728 | ||
1729 | switch (gimple_assign_rhs_code (gs)) | |
1730 | { | |
1731 | case MULT_EXPR: | |
1732 | slsr_process_mul (gs, rhs1, rhs2, speed); | |
1733 | break; | |
1734 | ||
1735 | case PLUS_EXPR: | |
1736 | case POINTER_PLUS_EXPR: | |
1737 | case MINUS_EXPR: | |
1738 | slsr_process_add (gs, rhs1, rhs2, speed); | |
1739 | break; | |
1740 | ||
1741 | case NEGATE_EXPR: | |
1742 | slsr_process_neg (gs, rhs1, speed); | |
1743 | break; | |
1744 | ||
1745 | case NOP_EXPR: | |
1746 | slsr_process_cast (gs, rhs1, speed); | |
1747 | break; | |
1748 | ||
1749 | case MODIFY_EXPR: | |
1750 | slsr_process_copy (gs, rhs1, speed); | |
1751 | break; | |
1752 | ||
1753 | default: | |
1754 | ; | |
1755 | } | |
1756 | } | |
1757 | } | |
1758 | } | |
1759 | \f | |
1760 | /* Dump a candidate for debug. */ | |
1761 | ||
1762 | static void | |
1763 | dump_candidate (slsr_cand_t c) | |
1764 | { | |
1765 | fprintf (dump_file, "%3d [%d] ", c->cand_num, | |
1766 | gimple_bb (c->cand_stmt)->index); | |
1767 | print_gimple_stmt (dump_file, c->cand_stmt, 0, 0); | |
1768 | switch (c->kind) | |
1769 | { | |
1770 | case CAND_MULT: | |
1771 | fputs (" MULT : (", dump_file); | |
3cfd4469 | 1772 | print_generic_expr (dump_file, c->base_expr, 0); |
f9453c07 BS |
1773 | fputs (" + ", dump_file); |
1774 | dump_double_int (dump_file, c->index, false); | |
1775 | fputs (") * ", dump_file); | |
1776 | print_generic_expr (dump_file, c->stride, 0); | |
1777 | fputs (" : ", dump_file); | |
1778 | break; | |
1779 | case CAND_ADD: | |
1780 | fputs (" ADD : ", dump_file); | |
3cfd4469 | 1781 | print_generic_expr (dump_file, c->base_expr, 0); |
f9453c07 BS |
1782 | fputs (" + (", dump_file); |
1783 | dump_double_int (dump_file, c->index, false); | |
1784 | fputs (" * ", dump_file); | |
1785 | print_generic_expr (dump_file, c->stride, 0); | |
1786 | fputs (") : ", dump_file); | |
1787 | break; | |
2749c8f6 BS |
1788 | case CAND_REF: |
1789 | fputs (" REF : ", dump_file); | |
3cfd4469 | 1790 | print_generic_expr (dump_file, c->base_expr, 0); |
2749c8f6 BS |
1791 | fputs (" + (", dump_file); |
1792 | print_generic_expr (dump_file, c->stride, 0); | |
1793 | fputs (") + ", dump_file); | |
1794 | dump_double_int (dump_file, c->index, false); | |
1795 | fputs (" : ", dump_file); | |
1796 | break; | |
9b92d12b BS |
1797 | case CAND_PHI: |
1798 | fputs (" PHI : ", dump_file); | |
1799 | print_generic_expr (dump_file, c->base_expr, 0); | |
1800 | fputs (" + (unknown * ", dump_file); | |
1801 | print_generic_expr (dump_file, c->stride, 0); | |
1802 | fputs (") : ", dump_file); | |
1803 | break; | |
f9453c07 BS |
1804 | default: |
1805 | gcc_unreachable (); | |
1806 | } | |
1807 | print_generic_expr (dump_file, c->cand_type, 0); | |
1808 | fprintf (dump_file, "\n basis: %d dependent: %d sibling: %d\n", | |
1809 | c->basis, c->dependent, c->sibling); | |
1810 | fprintf (dump_file, " next-interp: %d dead-savings: %d\n", | |
1811 | c->next_interp, c->dead_savings); | |
1812 | if (c->def_phi) | |
9b92d12b | 1813 | fprintf (dump_file, " phi: %d\n", c->def_phi); |
f9453c07 BS |
1814 | fputs ("\n", dump_file); |
1815 | } | |
1816 | ||
1817 | /* Dump the candidate vector for debug. */ | |
1818 | ||
1819 | static void | |
1820 | dump_cand_vec (void) | |
1821 | { | |
1822 | unsigned i; | |
1823 | slsr_cand_t c; | |
1824 | ||
1825 | fprintf (dump_file, "\nStrength reduction candidate vector:\n\n"); | |
1826 | ||
9771b263 | 1827 | FOR_EACH_VEC_ELT (cand_vec, i, c) |
f9453c07 BS |
1828 | dump_candidate (c); |
1829 | } | |
1830 | ||
2749c8f6 | 1831 | /* Callback used to dump the candidate chains hash table. */ |
f9453c07 | 1832 | |
4a8fb1a1 LC |
1833 | int |
1834 | ssa_base_cand_dump_callback (cand_chain **slot, void *ignored ATTRIBUTE_UNUSED) | |
f9453c07 | 1835 | { |
4a8fb1a1 | 1836 | const_cand_chain_t chain = *slot; |
2749c8f6 | 1837 | cand_chain_t p; |
f9453c07 | 1838 | |
3cfd4469 | 1839 | print_generic_expr (dump_file, chain->base_expr, 0); |
2749c8f6 | 1840 | fprintf (dump_file, " -> %d", chain->cand->cand_num); |
f9453c07 | 1841 | |
2749c8f6 BS |
1842 | for (p = chain->next; p; p = p->next) |
1843 | fprintf (dump_file, " -> %d", p->cand->cand_num); | |
f9453c07 | 1844 | |
2749c8f6 BS |
1845 | fputs ("\n", dump_file); |
1846 | return 1; | |
1847 | } | |
f9453c07 | 1848 | |
2749c8f6 | 1849 | /* Dump the candidate chains. */ |
f9453c07 | 1850 | |
2749c8f6 BS |
1851 | static void |
1852 | dump_cand_chains (void) | |
1853 | { | |
1854 | fprintf (dump_file, "\nStrength reduction candidate chains:\n\n"); | |
4a8fb1a1 | 1855 | base_cand_map.traverse_noresize <void *, ssa_base_cand_dump_callback> (NULL); |
f9453c07 BS |
1856 | fputs ("\n", dump_file); |
1857 | } | |
88ca9ea1 BS |
1858 | |
1859 | /* Dump the increment vector for debug. */ | |
1860 | ||
1861 | static void | |
1862 | dump_incr_vec (void) | |
1863 | { | |
1864 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1865 | { | |
1866 | unsigned i; | |
1867 | ||
1868 | fprintf (dump_file, "\nIncrement vector:\n\n"); | |
1869 | ||
1870 | for (i = 0; i < incr_vec_len; i++) | |
1871 | { | |
1872 | fprintf (dump_file, "%3d increment: ", i); | |
1873 | dump_double_int (dump_file, incr_vec[i].incr, false); | |
1874 | fprintf (dump_file, "\n count: %d", incr_vec[i].count); | |
1875 | fprintf (dump_file, "\n cost: %d", incr_vec[i].cost); | |
1876 | fputs ("\n initializer: ", dump_file); | |
1877 | print_generic_expr (dump_file, incr_vec[i].initializer, 0); | |
1878 | fputs ("\n\n", dump_file); | |
1879 | } | |
1880 | } | |
1881 | } | |
f9453c07 | 1882 | \f |
2749c8f6 BS |
1883 | /* Replace *EXPR in candidate C with an equivalent strength-reduced |
1884 | data reference. */ | |
1885 | ||
1886 | static void | |
1887 | replace_ref (tree *expr, slsr_cand_t c) | |
1888 | { | |
78f6dd68 MJ |
1889 | tree add_expr, mem_ref, acc_type = TREE_TYPE (*expr); |
1890 | unsigned HOST_WIDE_INT misalign; | |
1891 | unsigned align; | |
1892 | ||
1893 | /* Ensure the memory reference carries the minimum alignment | |
1894 | requirement for the data type. See PR58041. */ | |
1895 | get_object_alignment_1 (*expr, &align, &misalign); | |
1896 | if (misalign != 0) | |
1897 | align = (misalign & -misalign); | |
1898 | if (align < TYPE_ALIGN (acc_type)) | |
1899 | acc_type = build_aligned_type (acc_type, align); | |
1900 | ||
1901 | add_expr = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (c->base_expr), | |
1902 | c->base_expr, c->stride); | |
1903 | mem_ref = fold_build2 (MEM_REF, acc_type, add_expr, | |
1904 | double_int_to_tree (c->cand_type, c->index)); | |
1905 | ||
2749c8f6 BS |
1906 | /* Gimplify the base addressing expression for the new MEM_REF tree. */ |
1907 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
1908 | TREE_OPERAND (mem_ref, 0) | |
1909 | = force_gimple_operand_gsi (&gsi, TREE_OPERAND (mem_ref, 0), | |
1910 | /*simple_p=*/true, NULL, | |
1911 | /*before=*/true, GSI_SAME_STMT); | |
1912 | copy_ref_info (mem_ref, *expr); | |
1913 | *expr = mem_ref; | |
1914 | update_stmt (c->cand_stmt); | |
1915 | } | |
1916 | ||
1917 | /* Replace CAND_REF candidate C, each sibling of candidate C, and each | |
1918 | dependent of candidate C with an equivalent strength-reduced data | |
1919 | reference. */ | |
1920 | ||
1921 | static void | |
1922 | replace_refs (slsr_cand_t c) | |
1923 | { | |
96d75a2c YZ |
1924 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1925 | { | |
1926 | fputs ("Replacing reference: ", dump_file); | |
1927 | print_gimple_stmt (dump_file, c->cand_stmt, 0, 0); | |
1928 | } | |
1929 | ||
2749c8f6 BS |
1930 | if (gimple_vdef (c->cand_stmt)) |
1931 | { | |
1932 | tree *lhs = gimple_assign_lhs_ptr (c->cand_stmt); | |
1933 | replace_ref (lhs, c); | |
1934 | } | |
1935 | else | |
1936 | { | |
1937 | tree *rhs = gimple_assign_rhs1_ptr (c->cand_stmt); | |
1938 | replace_ref (rhs, c); | |
1939 | } | |
1940 | ||
96d75a2c YZ |
1941 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1942 | { | |
1943 | fputs ("With: ", dump_file); | |
1944 | print_gimple_stmt (dump_file, c->cand_stmt, 0, 0); | |
1945 | fputs ("\n", dump_file); | |
1946 | } | |
1947 | ||
2749c8f6 BS |
1948 | if (c->sibling) |
1949 | replace_refs (lookup_cand (c->sibling)); | |
1950 | ||
1951 | if (c->dependent) | |
1952 | replace_refs (lookup_cand (c->dependent)); | |
1953 | } | |
1954 | ||
9b92d12b BS |
1955 | /* Return TRUE if candidate C is dependent upon a PHI. */ |
1956 | ||
1957 | static bool | |
1958 | phi_dependent_cand_p (slsr_cand_t c) | |
1959 | { | |
1960 | /* A candidate is not necessarily dependent upon a PHI just because | |
1961 | it has a phi definition for its base name. It may have a basis | |
1962 | that relies upon the same phi definition, in which case the PHI | |
1963 | is irrelevant to this candidate. */ | |
1964 | return (c->def_phi | |
1965 | && c->basis | |
1966 | && lookup_cand (c->basis)->def_phi != c->def_phi); | |
1967 | } | |
1968 | ||
f9453c07 BS |
1969 | /* Calculate the increment required for candidate C relative to |
1970 | its basis. */ | |
1971 | ||
1972 | static double_int | |
1973 | cand_increment (slsr_cand_t c) | |
1974 | { | |
1975 | slsr_cand_t basis; | |
1976 | ||
1977 | /* If the candidate doesn't have a basis, just return its own | |
1978 | index. This is useful in record_increments to help us find | |
9b92d12b BS |
1979 | an existing initializer. Also, if the candidate's basis is |
1980 | hidden by a phi, then its own index will be the increment | |
1981 | from the newly introduced phi basis. */ | |
1982 | if (!c->basis || phi_dependent_cand_p (c)) | |
f9453c07 BS |
1983 | return c->index; |
1984 | ||
1985 | basis = lookup_cand (c->basis); | |
3cfd4469 | 1986 | gcc_assert (operand_equal_p (c->base_expr, basis->base_expr, 0)); |
27bcd47c | 1987 | return c->index - basis->index; |
f9453c07 BS |
1988 | } |
1989 | ||
88ca9ea1 BS |
1990 | /* Calculate the increment required for candidate C relative to |
1991 | its basis. If we aren't going to generate pointer arithmetic | |
1992 | for this candidate, return the absolute value of that increment | |
1993 | instead. */ | |
1994 | ||
1995 | static inline double_int | |
1996 | cand_abs_increment (slsr_cand_t c) | |
1997 | { | |
1998 | double_int increment = cand_increment (c); | |
1999 | ||
27bcd47c LC |
2000 | if (!address_arithmetic_p && increment.is_negative ()) |
2001 | increment = -increment; | |
88ca9ea1 BS |
2002 | |
2003 | return increment; | |
2004 | } | |
2005 | ||
f9453c07 BS |
2006 | /* Return TRUE iff candidate C has already been replaced under |
2007 | another interpretation. */ | |
2008 | ||
2009 | static inline bool | |
2010 | cand_already_replaced (slsr_cand_t c) | |
2011 | { | |
2012 | return (gimple_bb (c->cand_stmt) == 0); | |
2013 | } | |
2014 | ||
9b92d12b BS |
2015 | /* Common logic used by replace_unconditional_candidate and |
2016 | replace_conditional_candidate. */ | |
f9453c07 BS |
2017 | |
2018 | static void | |
a7a7d10e | 2019 | replace_mult_candidate (slsr_cand_t c, tree basis_name, double_int bump) |
f9453c07 | 2020 | { |
9b92d12b BS |
2021 | tree target_type = TREE_TYPE (gimple_assign_lhs (c->cand_stmt)); |
2022 | enum tree_code cand_code = gimple_assign_rhs_code (c->cand_stmt); | |
2023 | ||
f9453c07 BS |
2024 | /* It is highly unlikely, but possible, that the resulting |
2025 | bump doesn't fit in a HWI. Abandon the replacement | |
9b92d12b BS |
2026 | in this case. This does not affect siblings or dependents |
2027 | of C. Restriction to signed HWI is conservative for unsigned | |
2028 | types but allows for safe negation without twisted logic. */ | |
2029 | if (bump.fits_shwi () | |
2030 | && bump.to_shwi () != HOST_WIDE_INT_MIN | |
2031 | /* It is not useful to replace casts, copies, or adds of | |
2032 | an SSA name and a constant. */ | |
2033 | && cand_code != MODIFY_EXPR | |
2034 | && cand_code != NOP_EXPR | |
2035 | && cand_code != PLUS_EXPR | |
2036 | && cand_code != POINTER_PLUS_EXPR | |
2037 | && cand_code != MINUS_EXPR) | |
2038 | { | |
2039 | enum tree_code code = PLUS_EXPR; | |
2040 | tree bump_tree; | |
2041 | gimple stmt_to_print = NULL; | |
2042 | ||
2043 | /* If the basis name and the candidate's LHS have incompatible | |
2044 | types, introduce a cast. */ | |
2045 | if (!useless_type_conversion_p (target_type, TREE_TYPE (basis_name))) | |
a7a7d10e | 2046 | basis_name = introduce_cast_before_cand (c, target_type, basis_name); |
9b92d12b BS |
2047 | if (bump.is_negative ()) |
2048 | { | |
2049 | code = MINUS_EXPR; | |
2050 | bump = -bump; | |
2051 | } | |
2052 | ||
2053 | bump_tree = double_int_to_tree (target_type, bump); | |
2054 | ||
2055 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2056 | { | |
2057 | fputs ("Replacing: ", dump_file); | |
2058 | print_gimple_stmt (dump_file, c->cand_stmt, 0, 0); | |
2059 | } | |
2060 | ||
2061 | if (bump.is_zero ()) | |
2062 | { | |
2063 | tree lhs = gimple_assign_lhs (c->cand_stmt); | |
2064 | gimple copy_stmt = gimple_build_assign (lhs, basis_name); | |
2065 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
2066 | gimple_set_location (copy_stmt, gimple_location (c->cand_stmt)); | |
2067 | gsi_replace (&gsi, copy_stmt, false); | |
0100cd3f | 2068 | c->cand_stmt = copy_stmt; |
9b92d12b BS |
2069 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2070 | stmt_to_print = copy_stmt; | |
2071 | } | |
2072 | else | |
2073 | { | |
2074 | tree rhs1, rhs2; | |
2075 | if (cand_code != NEGATE_EXPR) { | |
2076 | rhs1 = gimple_assign_rhs1 (c->cand_stmt); | |
2077 | rhs2 = gimple_assign_rhs2 (c->cand_stmt); | |
2078 | } | |
2079 | if (cand_code != NEGATE_EXPR | |
2080 | && ((operand_equal_p (rhs1, basis_name, 0) | |
2081 | && operand_equal_p (rhs2, bump_tree, 0)) | |
2082 | || (operand_equal_p (rhs1, bump_tree, 0) | |
2083 | && operand_equal_p (rhs2, basis_name, 0)))) | |
2084 | { | |
2085 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2086 | { | |
2087 | fputs ("(duplicate, not actually replacing)", dump_file); | |
2088 | stmt_to_print = c->cand_stmt; | |
2089 | } | |
2090 | } | |
2091 | else | |
2092 | { | |
2093 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
2094 | gimple_assign_set_rhs_with_ops (&gsi, code, | |
2095 | basis_name, bump_tree); | |
2096 | update_stmt (gsi_stmt (gsi)); | |
bb0d2039 | 2097 | c->cand_stmt = gsi_stmt (gsi); |
9b92d12b BS |
2098 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2099 | stmt_to_print = gsi_stmt (gsi); | |
2100 | } | |
2101 | } | |
2102 | ||
2103 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2104 | { | |
2105 | fputs ("With: ", dump_file); | |
2106 | print_gimple_stmt (dump_file, stmt_to_print, 0, 0); | |
2107 | fputs ("\n", dump_file); | |
2108 | } | |
2109 | } | |
2110 | } | |
2111 | ||
2112 | /* Replace candidate C with an add or subtract. Note that we only | |
2113 | operate on CAND_MULTs with known strides, so we will never generate | |
2114 | a POINTER_PLUS_EXPR. Each candidate X = (B + i) * S is replaced by | |
2115 | X = Y + ((i - i') * S), as described in the module commentary. The | |
2116 | folded value ((i - i') * S) is referred to here as the "bump." */ | |
2117 | ||
2118 | static void | |
2119 | replace_unconditional_candidate (slsr_cand_t c) | |
2120 | { | |
2121 | slsr_cand_t basis; | |
2122 | double_int stride, bump; | |
9b92d12b BS |
2123 | |
2124 | if (cand_already_replaced (c)) | |
f9453c07 BS |
2125 | return; |
2126 | ||
2127 | basis = lookup_cand (c->basis); | |
9b92d12b BS |
2128 | stride = tree_to_double_int (c->stride); |
2129 | bump = cand_increment (c) * stride; | |
2130 | ||
a7a7d10e | 2131 | replace_mult_candidate (c, gimple_assign_lhs (basis->cand_stmt), bump); |
9b92d12b BS |
2132 | } |
2133 | \f | |
7bf55a70 BS |
2134 | /* Return the index in the increment vector of the given INCREMENT, |
2135 | or -1 if not found. The latter can occur if more than | |
2136 | MAX_INCR_VEC_LEN increments have been found. */ | |
9b92d12b | 2137 | |
7bf55a70 | 2138 | static inline int |
9b92d12b BS |
2139 | incr_vec_index (double_int increment) |
2140 | { | |
2141 | unsigned i; | |
2142 | ||
2143 | for (i = 0; i < incr_vec_len && increment != incr_vec[i].incr; i++) | |
2144 | ; | |
2145 | ||
7bf55a70 BS |
2146 | if (i < incr_vec_len) |
2147 | return i; | |
2148 | else | |
2149 | return -1; | |
9b92d12b BS |
2150 | } |
2151 | ||
2152 | /* Create a new statement along edge E to add BASIS_NAME to the product | |
2153 | of INCREMENT and the stride of candidate C. Create and return a new | |
2154 | SSA name from *VAR to be used as the LHS of the new statement. | |
2155 | KNOWN_STRIDE is true iff C's stride is a constant. */ | |
2156 | ||
2157 | static tree | |
2158 | create_add_on_incoming_edge (slsr_cand_t c, tree basis_name, | |
2159 | double_int increment, edge e, location_t loc, | |
2160 | bool known_stride) | |
2161 | { | |
2162 | basic_block insert_bb; | |
2163 | gimple_stmt_iterator gsi; | |
2164 | tree lhs, basis_type; | |
2165 | gimple new_stmt; | |
2166 | ||
2167 | /* If the add candidate along this incoming edge has the same | |
2168 | index as C's hidden basis, the hidden basis represents this | |
2169 | edge correctly. */ | |
2170 | if (increment.is_zero ()) | |
2171 | return basis_name; | |
2172 | ||
2173 | basis_type = TREE_TYPE (basis_name); | |
2174 | lhs = make_temp_ssa_name (basis_type, NULL, "slsr"); | |
2175 | ||
2176 | if (known_stride) | |
7139194b | 2177 | { |
9b92d12b BS |
2178 | tree bump_tree; |
2179 | enum tree_code code = PLUS_EXPR; | |
2180 | double_int bump = increment * tree_to_double_int (c->stride); | |
2181 | if (bump.is_negative ()) | |
2182 | { | |
2183 | code = MINUS_EXPR; | |
2184 | bump = -bump; | |
2185 | } | |
2186 | ||
2187 | bump_tree = double_int_to_tree (basis_type, bump); | |
2188 | new_stmt = gimple_build_assign_with_ops (code, lhs, basis_name, | |
2189 | bump_tree); | |
7139194b AH |
2190 | } |
2191 | else | |
2192 | { | |
7bf55a70 | 2193 | int i; |
9b92d12b BS |
2194 | bool negate_incr = (!address_arithmetic_p && increment.is_negative ()); |
2195 | i = incr_vec_index (negate_incr ? -increment : increment); | |
7bf55a70 | 2196 | gcc_assert (i >= 0); |
f9453c07 | 2197 | |
9b92d12b BS |
2198 | if (incr_vec[i].initializer) |
2199 | { | |
2200 | enum tree_code code = negate_incr ? MINUS_EXPR : PLUS_EXPR; | |
2201 | new_stmt = gimple_build_assign_with_ops (code, lhs, basis_name, | |
2202 | incr_vec[i].initializer); | |
2203 | } | |
2204 | else if (increment.is_one ()) | |
2205 | new_stmt = gimple_build_assign_with_ops (PLUS_EXPR, lhs, basis_name, | |
2206 | c->stride); | |
2207 | else if (increment.is_minus_one ()) | |
2208 | new_stmt = gimple_build_assign_with_ops (MINUS_EXPR, lhs, basis_name, | |
2209 | c->stride); | |
2210 | else | |
2211 | gcc_unreachable (); | |
f9453c07 BS |
2212 | } |
2213 | ||
9b92d12b BS |
2214 | insert_bb = single_succ_p (e->src) ? e->src : split_edge (e); |
2215 | gsi = gsi_last_bb (insert_bb); | |
2216 | ||
2217 | if (!gsi_end_p (gsi) && is_ctrl_stmt (gsi_stmt (gsi))) | |
2218 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); | |
2219 | else | |
2220 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); | |
2221 | ||
2222 | gimple_set_location (new_stmt, loc); | |
f9453c07 BS |
2223 | |
2224 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2225 | { | |
9b92d12b BS |
2226 | fprintf (dump_file, "Inserting in block %d: ", insert_bb->index); |
2227 | print_gimple_stmt (dump_file, new_stmt, 0, 0); | |
f9453c07 BS |
2228 | } |
2229 | ||
9b92d12b BS |
2230 | return lhs; |
2231 | } | |
2232 | ||
2233 | /* Given a candidate C with BASIS_NAME being the LHS of C's basis which | |
2234 | is hidden by the phi node FROM_PHI, create a new phi node in the same | |
2235 | block as FROM_PHI. The new phi is suitable for use as a basis by C, | |
2236 | with its phi arguments representing conditional adjustments to the | |
2237 | hidden basis along conditional incoming paths. Those adjustments are | |
2238 | made by creating add statements (and sometimes recursively creating | |
2239 | phis) along those incoming paths. LOC is the location to attach to | |
2240 | the introduced statements. KNOWN_STRIDE is true iff C's stride is a | |
2241 | constant. */ | |
2242 | ||
2243 | static tree | |
2244 | create_phi_basis (slsr_cand_t c, gimple from_phi, tree basis_name, | |
2245 | location_t loc, bool known_stride) | |
2246 | { | |
2247 | int i; | |
2248 | tree name, phi_arg; | |
2249 | gimple phi; | |
2250 | vec<tree> phi_args; | |
2251 | slsr_cand_t basis = lookup_cand (c->basis); | |
2252 | int nargs = gimple_phi_num_args (from_phi); | |
2253 | basic_block phi_bb = gimple_bb (from_phi); | |
2254 | slsr_cand_t phi_cand = base_cand_from_table (gimple_phi_result (from_phi)); | |
2255 | phi_args.create (nargs); | |
2256 | ||
2257 | /* Process each argument of the existing phi that represents | |
2258 | conditionally-executed add candidates. */ | |
2259 | for (i = 0; i < nargs; i++) | |
f9453c07 | 2260 | { |
9b92d12b BS |
2261 | edge e = (*phi_bb->preds)[i]; |
2262 | tree arg = gimple_phi_arg_def (from_phi, i); | |
2263 | tree feeding_def; | |
2264 | ||
2265 | /* If the phi argument is the base name of the CAND_PHI, then | |
2266 | this incoming arc should use the hidden basis. */ | |
2267 | if (operand_equal_p (arg, phi_cand->base_expr, 0)) | |
2268 | if (basis->index.is_zero ()) | |
2269 | feeding_def = gimple_assign_lhs (basis->cand_stmt); | |
2270 | else | |
2271 | { | |
28708525 | 2272 | double_int incr = -basis->index; |
9b92d12b BS |
2273 | feeding_def = create_add_on_incoming_edge (c, basis_name, incr, |
2274 | e, loc, known_stride); | |
2275 | } | |
2276 | else | |
f9453c07 | 2277 | { |
9b92d12b BS |
2278 | gimple arg_def = SSA_NAME_DEF_STMT (arg); |
2279 | ||
2280 | /* If there is another phi along this incoming edge, we must | |
2281 | process it in the same fashion to ensure that all basis | |
2282 | adjustments are made along its incoming edges. */ | |
2283 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
2284 | feeding_def = create_phi_basis (c, arg_def, basis_name, | |
2285 | loc, known_stride); | |
2286 | else | |
f9453c07 | 2287 | { |
9b92d12b BS |
2288 | slsr_cand_t arg_cand = base_cand_from_table (arg); |
2289 | double_int diff = arg_cand->index - basis->index; | |
2290 | feeding_def = create_add_on_incoming_edge (c, basis_name, diff, | |
2291 | e, loc, known_stride); | |
f9453c07 BS |
2292 | } |
2293 | } | |
9b92d12b BS |
2294 | |
2295 | /* Because of recursion, we need to save the arguments in a vector | |
2296 | so we can create the PHI statement all at once. Otherwise the | |
2297 | storage for the half-created PHI can be reclaimed. */ | |
2298 | phi_args.safe_push (feeding_def); | |
f9453c07 | 2299 | } |
9b92d12b BS |
2300 | |
2301 | /* Create the new phi basis. */ | |
2302 | name = make_temp_ssa_name (TREE_TYPE (basis_name), NULL, "slsr"); | |
2303 | phi = create_phi_node (name, phi_bb); | |
2304 | SSA_NAME_DEF_STMT (name) = phi; | |
2305 | ||
2306 | FOR_EACH_VEC_ELT (phi_args, i, phi_arg) | |
2307 | { | |
2308 | edge e = (*phi_bb->preds)[i]; | |
2309 | add_phi_arg (phi, phi_arg, e, loc); | |
2310 | } | |
2311 | ||
2312 | update_stmt (phi); | |
2313 | ||
f9453c07 BS |
2314 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2315 | { | |
9b92d12b BS |
2316 | fputs ("Introducing new phi basis: ", dump_file); |
2317 | print_gimple_stmt (dump_file, phi, 0, 0); | |
f9453c07 | 2318 | } |
9b92d12b BS |
2319 | |
2320 | return name; | |
f9453c07 BS |
2321 | } |
2322 | ||
9b92d12b BS |
2323 | /* Given a candidate C whose basis is hidden by at least one intervening |
2324 | phi, introduce a matching number of new phis to represent its basis | |
2325 | adjusted by conditional increments along possible incoming paths. Then | |
2326 | replace C as though it were an unconditional candidate, using the new | |
2327 | basis. */ | |
f9453c07 BS |
2328 | |
2329 | static void | |
9b92d12b | 2330 | replace_conditional_candidate (slsr_cand_t c) |
f9453c07 | 2331 | { |
a7a7d10e | 2332 | tree basis_name, name; |
9b92d12b BS |
2333 | slsr_cand_t basis; |
2334 | location_t loc; | |
2335 | double_int stride, bump; | |
f9453c07 | 2336 | |
9b92d12b BS |
2337 | /* Look up the LHS SSA name from C's basis. This will be the |
2338 | RHS1 of the adds we will introduce to create new phi arguments. */ | |
2339 | basis = lookup_cand (c->basis); | |
2340 | basis_name = gimple_assign_lhs (basis->cand_stmt); | |
f9453c07 | 2341 | |
9b92d12b BS |
2342 | /* Create a new phi statement which will represent C's true basis |
2343 | after the transformation is complete. */ | |
2344 | loc = gimple_location (c->cand_stmt); | |
2345 | name = create_phi_basis (c, lookup_cand (c->def_phi)->cand_stmt, | |
2346 | basis_name, loc, KNOWN_STRIDE); | |
2347 | /* Replace C with an add of the new basis phi and a constant. */ | |
2348 | stride = tree_to_double_int (c->stride); | |
2349 | bump = c->index * stride; | |
f9453c07 | 2350 | |
a7a7d10e | 2351 | replace_mult_candidate (c, name, bump); |
f9453c07 | 2352 | } |
88ca9ea1 | 2353 | |
9b92d12b BS |
2354 | /* Compute the expected costs of inserting basis adjustments for |
2355 | candidate C with phi-definition PHI. The cost of inserting | |
2356 | one adjustment is given by ONE_ADD_COST. If PHI has arguments | |
2357 | which are themselves phi results, recursively calculate costs | |
2358 | for those phis as well. */ | |
2359 | ||
2360 | static int | |
2361 | phi_add_costs (gimple phi, slsr_cand_t c, int one_add_cost) | |
88ca9ea1 BS |
2362 | { |
2363 | unsigned i; | |
9b92d12b BS |
2364 | int cost = 0; |
2365 | slsr_cand_t phi_cand = base_cand_from_table (gimple_phi_result (phi)); | |
88ca9ea1 | 2366 | |
0100cd3f BS |
2367 | /* If we work our way back to a phi that isn't dominated by the hidden |
2368 | basis, this isn't a candidate for replacement. Indicate this by | |
2369 | returning an unreasonably high cost. It's not easy to detect | |
2370 | these situations when determining the basis, so we defer the | |
2371 | decision until now. */ | |
2372 | basic_block phi_bb = gimple_bb (phi); | |
2373 | slsr_cand_t basis = lookup_cand (c->basis); | |
2374 | basic_block basis_bb = gimple_bb (basis->cand_stmt); | |
2375 | ||
2376 | if (phi_bb == basis_bb || !dominated_by_p (CDI_DOMINATORS, phi_bb, basis_bb)) | |
2377 | return COST_INFINITE; | |
2378 | ||
9b92d12b BS |
2379 | for (i = 0; i < gimple_phi_num_args (phi); i++) |
2380 | { | |
2381 | tree arg = gimple_phi_arg_def (phi, i); | |
2382 | ||
2383 | if (arg != phi_cand->base_expr) | |
2384 | { | |
2385 | gimple arg_def = SSA_NAME_DEF_STMT (arg); | |
2386 | ||
2387 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
2388 | cost += phi_add_costs (arg_def, c, one_add_cost); | |
2389 | else | |
2390 | { | |
2391 | slsr_cand_t arg_cand = base_cand_from_table (arg); | |
2392 | ||
2393 | if (arg_cand->index != c->index) | |
2394 | cost += one_add_cost; | |
2395 | } | |
2396 | } | |
2397 | } | |
2398 | ||
2399 | return cost; | |
88ca9ea1 BS |
2400 | } |
2401 | ||
9b92d12b BS |
2402 | /* For candidate C, each sibling of candidate C, and each dependent of |
2403 | candidate C, determine whether the candidate is dependent upon a | |
2404 | phi that hides its basis. If not, replace the candidate unconditionally. | |
2405 | Otherwise, determine whether the cost of introducing compensation code | |
2406 | for the candidate is offset by the gains from strength reduction. If | |
2407 | so, replace the candidate and introduce the compensation code. */ | |
2408 | ||
2409 | static void | |
2410 | replace_uncond_cands_and_profitable_phis (slsr_cand_t c) | |
2411 | { | |
2412 | if (phi_dependent_cand_p (c)) | |
2413 | { | |
2414 | if (c->kind == CAND_MULT) | |
2415 | { | |
2416 | /* A candidate dependent upon a phi will replace a multiply by | |
2417 | a constant with an add, and will insert at most one add for | |
2418 | each phi argument. Add these costs with the potential dead-code | |
2419 | savings to determine profitability. */ | |
2420 | bool speed = optimize_bb_for_speed_p (gimple_bb (c->cand_stmt)); | |
2421 | int mult_savings = stmt_cost (c->cand_stmt, speed); | |
2422 | gimple phi = lookup_cand (c->def_phi)->cand_stmt; | |
2423 | tree phi_result = gimple_phi_result (phi); | |
2424 | int one_add_cost = add_cost (speed, | |
2425 | TYPE_MODE (TREE_TYPE (phi_result))); | |
2426 | int add_costs = one_add_cost + phi_add_costs (phi, c, one_add_cost); | |
2427 | int cost = add_costs - mult_savings - c->dead_savings; | |
2428 | ||
2429 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2430 | { | |
2431 | fprintf (dump_file, " Conditional candidate %d:\n", c->cand_num); | |
2432 | fprintf (dump_file, " add_costs = %d\n", add_costs); | |
2433 | fprintf (dump_file, " mult_savings = %d\n", mult_savings); | |
2434 | fprintf (dump_file, " dead_savings = %d\n", c->dead_savings); | |
2435 | fprintf (dump_file, " cost = %d\n", cost); | |
2436 | if (cost <= COST_NEUTRAL) | |
2437 | fputs (" Replacing...\n", dump_file); | |
2438 | else | |
2439 | fputs (" Not replaced.\n", dump_file); | |
2440 | } | |
2441 | ||
2442 | if (cost <= COST_NEUTRAL) | |
2443 | replace_conditional_candidate (c); | |
2444 | } | |
2445 | } | |
2446 | else | |
2447 | replace_unconditional_candidate (c); | |
2448 | ||
2449 | if (c->sibling) | |
2450 | replace_uncond_cands_and_profitable_phis (lookup_cand (c->sibling)); | |
2451 | ||
2452 | if (c->dependent) | |
2453 | replace_uncond_cands_and_profitable_phis (lookup_cand (c->dependent)); | |
2454 | } | |
2455 | \f | |
88ca9ea1 BS |
2456 | /* Count the number of candidates in the tree rooted at C that have |
2457 | not already been replaced under other interpretations. */ | |
2458 | ||
1dc3d6e9 | 2459 | static int |
88ca9ea1 BS |
2460 | count_candidates (slsr_cand_t c) |
2461 | { | |
2462 | unsigned count = cand_already_replaced (c) ? 0 : 1; | |
2463 | ||
2464 | if (c->sibling) | |
2465 | count += count_candidates (lookup_cand (c->sibling)); | |
2466 | ||
2467 | if (c->dependent) | |
2468 | count += count_candidates (lookup_cand (c->dependent)); | |
2469 | ||
2470 | return count; | |
2471 | } | |
2472 | ||
2473 | /* Increase the count of INCREMENT by one in the increment vector. | |
9b92d12b BS |
2474 | INCREMENT is associated with candidate C. If INCREMENT is to be |
2475 | conditionally executed as part of a conditional candidate replacement, | |
2476 | IS_PHI_ADJUST is true, otherwise false. If an initializer | |
88ca9ea1 BS |
2477 | T_0 = stride * I is provided by a candidate that dominates all |
2478 | candidates with the same increment, also record T_0 for subsequent use. */ | |
2479 | ||
2480 | static void | |
9b92d12b | 2481 | record_increment (slsr_cand_t c, double_int increment, bool is_phi_adjust) |
88ca9ea1 BS |
2482 | { |
2483 | bool found = false; | |
2484 | unsigned i; | |
2485 | ||
2486 | /* Treat increments that differ only in sign as identical so as to | |
2487 | share initializers, unless we are generating pointer arithmetic. */ | |
27bcd47c LC |
2488 | if (!address_arithmetic_p && increment.is_negative ()) |
2489 | increment = -increment; | |
88ca9ea1 BS |
2490 | |
2491 | for (i = 0; i < incr_vec_len; i++) | |
2492 | { | |
27bcd47c | 2493 | if (incr_vec[i].incr == increment) |
88ca9ea1 BS |
2494 | { |
2495 | incr_vec[i].count++; | |
2496 | found = true; | |
2497 | ||
2498 | /* If we previously recorded an initializer that doesn't | |
2499 | dominate this candidate, it's not going to be useful to | |
2500 | us after all. */ | |
2501 | if (incr_vec[i].initializer | |
2502 | && !dominated_by_p (CDI_DOMINATORS, | |
2503 | gimple_bb (c->cand_stmt), | |
2504 | incr_vec[i].init_bb)) | |
2505 | { | |
2506 | incr_vec[i].initializer = NULL_TREE; | |
2507 | incr_vec[i].init_bb = NULL; | |
2508 | } | |
2509 | ||
2510 | break; | |
2511 | } | |
2512 | } | |
2513 | ||
7bf55a70 | 2514 | if (!found && incr_vec_len < MAX_INCR_VEC_LEN - 1) |
88ca9ea1 BS |
2515 | { |
2516 | /* The first time we see an increment, create the entry for it. | |
2517 | If this is the root candidate which doesn't have a basis, set | |
2518 | the count to zero. We're only processing it so it can possibly | |
2519 | provide an initializer for other candidates. */ | |
2520 | incr_vec[incr_vec_len].incr = increment; | |
9b92d12b | 2521 | incr_vec[incr_vec_len].count = c->basis || is_phi_adjust ? 1 : 0; |
88ca9ea1 BS |
2522 | incr_vec[incr_vec_len].cost = COST_INFINITE; |
2523 | ||
2524 | /* Optimistically record the first occurrence of this increment | |
2525 | as providing an initializer (if it does); we will revise this | |
2526 | opinion later if it doesn't dominate all other occurrences. | |
9b92d12b BS |
2527 | Exception: increments of -1, 0, 1 never need initializers; |
2528 | and phi adjustments don't ever provide initializers. */ | |
88ca9ea1 | 2529 | if (c->kind == CAND_ADD |
9b92d12b | 2530 | && !is_phi_adjust |
27bcd47c LC |
2531 | && c->index == increment |
2532 | && (increment.sgt (double_int_one) | |
7b8265ba JJ |
2533 | || increment.slt (double_int_minus_one)) |
2534 | && (gimple_assign_rhs_code (c->cand_stmt) == PLUS_EXPR | |
2535 | || gimple_assign_rhs_code (c->cand_stmt) == POINTER_PLUS_EXPR)) | |
88ca9ea1 | 2536 | { |
7b8265ba | 2537 | tree t0 = NULL_TREE; |
88ca9ea1 BS |
2538 | tree rhs1 = gimple_assign_rhs1 (c->cand_stmt); |
2539 | tree rhs2 = gimple_assign_rhs2 (c->cand_stmt); | |
2540 | if (operand_equal_p (rhs1, c->base_expr, 0)) | |
2541 | t0 = rhs2; | |
7b8265ba | 2542 | else if (operand_equal_p (rhs2, c->base_expr, 0)) |
88ca9ea1 | 2543 | t0 = rhs1; |
7b8265ba JJ |
2544 | if (t0 |
2545 | && SSA_NAME_DEF_STMT (t0) | |
2546 | && gimple_bb (SSA_NAME_DEF_STMT (t0))) | |
88ca9ea1 BS |
2547 | { |
2548 | incr_vec[incr_vec_len].initializer = t0; | |
2549 | incr_vec[incr_vec_len++].init_bb | |
2550 | = gimple_bb (SSA_NAME_DEF_STMT (t0)); | |
2551 | } | |
2552 | else | |
2553 | { | |
2554 | incr_vec[incr_vec_len].initializer = NULL_TREE; | |
2555 | incr_vec[incr_vec_len++].init_bb = NULL; | |
2556 | } | |
2557 | } | |
2558 | else | |
2559 | { | |
2560 | incr_vec[incr_vec_len].initializer = NULL_TREE; | |
2561 | incr_vec[incr_vec_len++].init_bb = NULL; | |
2562 | } | |
2563 | } | |
2564 | } | |
2565 | ||
9b92d12b BS |
2566 | /* Given phi statement PHI that hides a candidate from its BASIS, find |
2567 | the increments along each incoming arc (recursively handling additional | |
2568 | phis that may be present) and record them. These increments are the | |
2569 | difference in index between the index-adjusting statements and the | |
2570 | index of the basis. */ | |
2571 | ||
2572 | static void | |
2573 | record_phi_increments (slsr_cand_t basis, gimple phi) | |
2574 | { | |
2575 | unsigned i; | |
2576 | slsr_cand_t phi_cand = base_cand_from_table (gimple_phi_result (phi)); | |
2577 | ||
2578 | for (i = 0; i < gimple_phi_num_args (phi); i++) | |
2579 | { | |
2580 | tree arg = gimple_phi_arg_def (phi, i); | |
2581 | ||
2582 | if (!operand_equal_p (arg, phi_cand->base_expr, 0)) | |
2583 | { | |
2584 | gimple arg_def = SSA_NAME_DEF_STMT (arg); | |
2585 | ||
2586 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
2587 | record_phi_increments (basis, arg_def); | |
2588 | else | |
2589 | { | |
2590 | slsr_cand_t arg_cand = base_cand_from_table (arg); | |
2591 | double_int diff = arg_cand->index - basis->index; | |
2592 | record_increment (arg_cand, diff, PHI_ADJUST); | |
2593 | } | |
2594 | } | |
2595 | } | |
2596 | } | |
2597 | ||
88ca9ea1 BS |
2598 | /* Determine how many times each unique increment occurs in the set |
2599 | of candidates rooted at C's parent, recording the data in the | |
2600 | increment vector. For each unique increment I, if an initializer | |
2601 | T_0 = stride * I is provided by a candidate that dominates all | |
2602 | candidates with the same increment, also record T_0 for subsequent | |
2603 | use. */ | |
2604 | ||
2605 | static void | |
2606 | record_increments (slsr_cand_t c) | |
2607 | { | |
2608 | if (!cand_already_replaced (c)) | |
9b92d12b BS |
2609 | { |
2610 | if (!phi_dependent_cand_p (c)) | |
2611 | record_increment (c, cand_increment (c), NOT_PHI_ADJUST); | |
2612 | else | |
2613 | { | |
2614 | /* A candidate with a basis hidden by a phi will have one | |
2615 | increment for its relationship to the index represented by | |
2616 | the phi, and potentially additional increments along each | |
2617 | incoming edge. For the root of the dependency tree (which | |
2618 | has no basis), process just the initial index in case it has | |
2619 | an initializer that can be used by subsequent candidates. */ | |
2620 | record_increment (c, c->index, NOT_PHI_ADJUST); | |
2621 | ||
2622 | if (c->basis) | |
2623 | record_phi_increments (lookup_cand (c->basis), | |
2624 | lookup_cand (c->def_phi)->cand_stmt); | |
2625 | } | |
2626 | } | |
88ca9ea1 BS |
2627 | |
2628 | if (c->sibling) | |
2629 | record_increments (lookup_cand (c->sibling)); | |
2630 | ||
2631 | if (c->dependent) | |
2632 | record_increments (lookup_cand (c->dependent)); | |
2633 | } | |
2634 | ||
9b92d12b BS |
2635 | /* Add up and return the costs of introducing add statements that |
2636 | require the increment INCR on behalf of candidate C and phi | |
2637 | statement PHI. Accumulate into *SAVINGS the potential savings | |
2638 | from removing existing statements that feed PHI and have no other | |
2639 | uses. */ | |
2640 | ||
2641 | static int | |
2642 | phi_incr_cost (slsr_cand_t c, double_int incr, gimple phi, int *savings) | |
2643 | { | |
2644 | unsigned i; | |
2645 | int cost = 0; | |
2646 | slsr_cand_t basis = lookup_cand (c->basis); | |
2647 | slsr_cand_t phi_cand = base_cand_from_table (gimple_phi_result (phi)); | |
2648 | ||
2649 | for (i = 0; i < gimple_phi_num_args (phi); i++) | |
2650 | { | |
2651 | tree arg = gimple_phi_arg_def (phi, i); | |
2652 | ||
2653 | if (!operand_equal_p (arg, phi_cand->base_expr, 0)) | |
2654 | { | |
2655 | gimple arg_def = SSA_NAME_DEF_STMT (arg); | |
2656 | ||
2657 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
2658 | { | |
2659 | int feeding_savings = 0; | |
2660 | cost += phi_incr_cost (c, incr, arg_def, &feeding_savings); | |
2661 | if (has_single_use (gimple_phi_result (arg_def))) | |
2662 | *savings += feeding_savings; | |
2663 | } | |
2664 | else | |
2665 | { | |
2666 | slsr_cand_t arg_cand = base_cand_from_table (arg); | |
2667 | double_int diff = arg_cand->index - basis->index; | |
2668 | ||
2669 | if (incr == diff) | |
2670 | { | |
2671 | tree basis_lhs = gimple_assign_lhs (basis->cand_stmt); | |
2672 | tree lhs = gimple_assign_lhs (arg_cand->cand_stmt); | |
2673 | cost += add_cost (true, TYPE_MODE (TREE_TYPE (basis_lhs))); | |
2674 | if (has_single_use (lhs)) | |
2675 | *savings += stmt_cost (arg_cand->cand_stmt, true); | |
2676 | } | |
2677 | } | |
2678 | } | |
2679 | } | |
2680 | ||
2681 | return cost; | |
2682 | } | |
2683 | ||
88ca9ea1 BS |
2684 | /* Return the first candidate in the tree rooted at C that has not |
2685 | already been replaced, favoring siblings over dependents. */ | |
2686 | ||
2687 | static slsr_cand_t | |
2688 | unreplaced_cand_in_tree (slsr_cand_t c) | |
2689 | { | |
2690 | if (!cand_already_replaced (c)) | |
2691 | return c; | |
2692 | ||
2693 | if (c->sibling) | |
2694 | { | |
2695 | slsr_cand_t sib = unreplaced_cand_in_tree (lookup_cand (c->sibling)); | |
2696 | if (sib) | |
2697 | return sib; | |
2698 | } | |
2699 | ||
2700 | if (c->dependent) | |
2701 | { | |
2702 | slsr_cand_t dep = unreplaced_cand_in_tree (lookup_cand (c->dependent)); | |
2703 | if (dep) | |
2704 | return dep; | |
2705 | } | |
2706 | ||
2707 | return NULL; | |
2708 | } | |
2709 | ||
2710 | /* Return TRUE if the candidates in the tree rooted at C should be | |
2711 | optimized for speed, else FALSE. We estimate this based on the block | |
2712 | containing the most dominant candidate in the tree that has not yet | |
2713 | been replaced. */ | |
2714 | ||
2715 | static bool | |
2716 | optimize_cands_for_speed_p (slsr_cand_t c) | |
2717 | { | |
2718 | slsr_cand_t c2 = unreplaced_cand_in_tree (c); | |
2719 | gcc_assert (c2); | |
2720 | return optimize_bb_for_speed_p (gimple_bb (c2->cand_stmt)); | |
2721 | } | |
2722 | ||
2723 | /* Add COST_IN to the lowest cost of any dependent path starting at | |
2724 | candidate C or any of its siblings, counting only candidates along | |
2725 | such paths with increment INCR. Assume that replacing a candidate | |
2726 | reduces cost by REPL_SAVINGS. Also account for savings from any | |
9b92d12b BS |
2727 | statements that would go dead. If COUNT_PHIS is true, include |
2728 | costs of introducing feeding statements for conditional candidates. */ | |
88ca9ea1 BS |
2729 | |
2730 | static int | |
9b92d12b BS |
2731 | lowest_cost_path (int cost_in, int repl_savings, slsr_cand_t c, |
2732 | double_int incr, bool count_phis) | |
88ca9ea1 | 2733 | { |
9b92d12b | 2734 | int local_cost, sib_cost, savings = 0; |
88ca9ea1 BS |
2735 | double_int cand_incr = cand_abs_increment (c); |
2736 | ||
2737 | if (cand_already_replaced (c)) | |
2738 | local_cost = cost_in; | |
27bcd47c | 2739 | else if (incr == cand_incr) |
88ca9ea1 BS |
2740 | local_cost = cost_in - repl_savings - c->dead_savings; |
2741 | else | |
2742 | local_cost = cost_in - c->dead_savings; | |
2743 | ||
9b92d12b BS |
2744 | if (count_phis |
2745 | && phi_dependent_cand_p (c) | |
2746 | && !cand_already_replaced (c)) | |
2747 | { | |
2748 | gimple phi = lookup_cand (c->def_phi)->cand_stmt; | |
2749 | local_cost += phi_incr_cost (c, incr, phi, &savings); | |
2750 | ||
2751 | if (has_single_use (gimple_phi_result (phi))) | |
2752 | local_cost -= savings; | |
2753 | } | |
2754 | ||
88ca9ea1 BS |
2755 | if (c->dependent) |
2756 | local_cost = lowest_cost_path (local_cost, repl_savings, | |
9b92d12b BS |
2757 | lookup_cand (c->dependent), incr, |
2758 | count_phis); | |
88ca9ea1 BS |
2759 | |
2760 | if (c->sibling) | |
2761 | { | |
2762 | sib_cost = lowest_cost_path (cost_in, repl_savings, | |
9b92d12b BS |
2763 | lookup_cand (c->sibling), incr, |
2764 | count_phis); | |
88ca9ea1 BS |
2765 | local_cost = MIN (local_cost, sib_cost); |
2766 | } | |
2767 | ||
2768 | return local_cost; | |
2769 | } | |
2770 | ||
2771 | /* Compute the total savings that would accrue from all replacements | |
2772 | in the candidate tree rooted at C, counting only candidates with | |
2773 | increment INCR. Assume that replacing a candidate reduces cost | |
2774 | by REPL_SAVINGS. Also account for savings from statements that | |
2775 | would go dead. */ | |
2776 | ||
2777 | static int | |
9b92d12b BS |
2778 | total_savings (int repl_savings, slsr_cand_t c, double_int incr, |
2779 | bool count_phis) | |
88ca9ea1 BS |
2780 | { |
2781 | int savings = 0; | |
2782 | double_int cand_incr = cand_abs_increment (c); | |
2783 | ||
27bcd47c | 2784 | if (incr == cand_incr && !cand_already_replaced (c)) |
88ca9ea1 BS |
2785 | savings += repl_savings + c->dead_savings; |
2786 | ||
9b92d12b BS |
2787 | if (count_phis |
2788 | && phi_dependent_cand_p (c) | |
2789 | && !cand_already_replaced (c)) | |
2790 | { | |
2791 | int phi_savings = 0; | |
2792 | gimple phi = lookup_cand (c->def_phi)->cand_stmt; | |
2793 | savings -= phi_incr_cost (c, incr, phi, &phi_savings); | |
2794 | ||
2795 | if (has_single_use (gimple_phi_result (phi))) | |
2796 | savings += phi_savings; | |
2797 | } | |
2798 | ||
88ca9ea1 | 2799 | if (c->dependent) |
9b92d12b BS |
2800 | savings += total_savings (repl_savings, lookup_cand (c->dependent), incr, |
2801 | count_phis); | |
88ca9ea1 BS |
2802 | |
2803 | if (c->sibling) | |
9b92d12b BS |
2804 | savings += total_savings (repl_savings, lookup_cand (c->sibling), incr, |
2805 | count_phis); | |
88ca9ea1 BS |
2806 | |
2807 | return savings; | |
2808 | } | |
2809 | ||
2810 | /* Use target-specific costs to determine and record which increments | |
2811 | in the current candidate tree are profitable to replace, assuming | |
2812 | MODE and SPEED. FIRST_DEP is the first dependent of the root of | |
2813 | the candidate tree. | |
2814 | ||
2815 | One slight limitation here is that we don't account for the possible | |
2816 | introduction of casts in some cases. See replace_one_candidate for | |
2817 | the cases where these are introduced. This should probably be cleaned | |
2818 | up sometime. */ | |
2819 | ||
2820 | static void | |
2821 | analyze_increments (slsr_cand_t first_dep, enum machine_mode mode, bool speed) | |
2822 | { | |
2823 | unsigned i; | |
2824 | ||
2825 | for (i = 0; i < incr_vec_len; i++) | |
2826 | { | |
27bcd47c | 2827 | HOST_WIDE_INT incr = incr_vec[i].incr.to_shwi (); |
88ca9ea1 BS |
2828 | |
2829 | /* If somehow this increment is bigger than a HWI, we won't | |
2830 | be optimizing candidates that use it. And if the increment | |
2831 | has a count of zero, nothing will be done with it. */ | |
27bcd47c | 2832 | if (!incr_vec[i].incr.fits_shwi () || !incr_vec[i].count) |
88ca9ea1 BS |
2833 | incr_vec[i].cost = COST_INFINITE; |
2834 | ||
2835 | /* Increments of 0, 1, and -1 are always profitable to replace, | |
2836 | because they always replace a multiply or add with an add or | |
2837 | copy, and may cause one or more existing instructions to go | |
2838 | dead. Exception: -1 can't be assumed to be profitable for | |
2839 | pointer addition. */ | |
2840 | else if (incr == 0 | |
2841 | || incr == 1 | |
2842 | || (incr == -1 | |
2843 | && (gimple_assign_rhs_code (first_dep->cand_stmt) | |
2844 | != POINTER_PLUS_EXPR))) | |
2845 | incr_vec[i].cost = COST_NEUTRAL; | |
2846 | ||
6b5eea61 BS |
2847 | /* FORNOW: If we need to add an initializer, give up if a cast from |
2848 | the candidate's type to its stride's type can lose precision. | |
2849 | This could eventually be handled better by expressly retaining the | |
2850 | result of a cast to a wider type in the stride. Example: | |
2851 | ||
2852 | short int _1; | |
2853 | _2 = (int) _1; | |
2854 | _3 = _2 * 10; | |
2855 | _4 = x + _3; ADD: x + (10 * _1) : int | |
2856 | _5 = _2 * 15; | |
2857 | _6 = x + _3; ADD: x + (15 * _1) : int | |
2858 | ||
2859 | Right now replacing _6 would cause insertion of an initializer | |
2860 | of the form "short int T = _1 * 5;" followed by a cast to | |
2861 | int, which could overflow incorrectly. Had we recorded _2 or | |
2862 | (int)_1 as the stride, this wouldn't happen. However, doing | |
2863 | this breaks other opportunities, so this will require some | |
2864 | care. */ | |
2865 | else if (!incr_vec[i].initializer | |
2866 | && TREE_CODE (first_dep->stride) != INTEGER_CST | |
2867 | && !legal_cast_p_1 (first_dep->stride, | |
2868 | gimple_assign_lhs (first_dep->cand_stmt))) | |
2869 | ||
2870 | incr_vec[i].cost = COST_INFINITE; | |
2871 | ||
50251425 BS |
2872 | /* If we need to add an initializer, make sure we don't introduce |
2873 | a multiply by a pointer type, which can happen in certain cast | |
2874 | scenarios. FIXME: When cleaning up these cast issues, we can | |
2875 | afford to introduce the multiply provided we cast out to an | |
2876 | unsigned int of appropriate size. */ | |
2877 | else if (!incr_vec[i].initializer | |
2878 | && TREE_CODE (first_dep->stride) != INTEGER_CST | |
2879 | && POINTER_TYPE_P (TREE_TYPE (first_dep->stride))) | |
2880 | ||
2881 | incr_vec[i].cost = COST_INFINITE; | |
2882 | ||
88ca9ea1 BS |
2883 | /* For any other increment, if this is a multiply candidate, we |
2884 | must introduce a temporary T and initialize it with | |
2885 | T_0 = stride * increment. When optimizing for speed, walk the | |
2886 | candidate tree to calculate the best cost reduction along any | |
2887 | path; if it offsets the fixed cost of inserting the initializer, | |
2888 | replacing the increment is profitable. When optimizing for | |
2889 | size, instead calculate the total cost reduction from replacing | |
2890 | all candidates with this increment. */ | |
2891 | else if (first_dep->kind == CAND_MULT) | |
2892 | { | |
2893 | int cost = mult_by_coeff_cost (incr, mode, speed); | |
2894 | int repl_savings = mul_cost (speed, mode) - add_cost (speed, mode); | |
2895 | if (speed) | |
2896 | cost = lowest_cost_path (cost, repl_savings, first_dep, | |
9b92d12b | 2897 | incr_vec[i].incr, COUNT_PHIS); |
88ca9ea1 | 2898 | else |
9b92d12b BS |
2899 | cost -= total_savings (repl_savings, first_dep, incr_vec[i].incr, |
2900 | COUNT_PHIS); | |
88ca9ea1 BS |
2901 | |
2902 | incr_vec[i].cost = cost; | |
2903 | } | |
2904 | ||
2905 | /* If this is an add candidate, the initializer may already | |
2906 | exist, so only calculate the cost of the initializer if it | |
2907 | doesn't. We are replacing one add with another here, so the | |
2908 | known replacement savings is zero. We will account for removal | |
2909 | of dead instructions in lowest_cost_path or total_savings. */ | |
2910 | else | |
2911 | { | |
2912 | int cost = 0; | |
2913 | if (!incr_vec[i].initializer) | |
2914 | cost = mult_by_coeff_cost (incr, mode, speed); | |
2915 | ||
2916 | if (speed) | |
9b92d12b BS |
2917 | cost = lowest_cost_path (cost, 0, first_dep, incr_vec[i].incr, |
2918 | DONT_COUNT_PHIS); | |
88ca9ea1 | 2919 | else |
9b92d12b BS |
2920 | cost -= total_savings (0, first_dep, incr_vec[i].incr, |
2921 | DONT_COUNT_PHIS); | |
88ca9ea1 BS |
2922 | |
2923 | incr_vec[i].cost = cost; | |
2924 | } | |
2925 | } | |
2926 | } | |
2927 | ||
2928 | /* Return the nearest common dominator of BB1 and BB2. If the blocks | |
2929 | are identical, return the earlier of C1 and C2 in *WHERE. Otherwise, | |
2930 | if the NCD matches BB1, return C1 in *WHERE; if the NCD matches BB2, | |
2931 | return C2 in *WHERE; and if the NCD matches neither, return NULL in | |
2932 | *WHERE. Note: It is possible for one of C1 and C2 to be NULL. */ | |
2933 | ||
2934 | static basic_block | |
2935 | ncd_for_two_cands (basic_block bb1, basic_block bb2, | |
2936 | slsr_cand_t c1, slsr_cand_t c2, slsr_cand_t *where) | |
2937 | { | |
2938 | basic_block ncd; | |
2939 | ||
2940 | if (!bb1) | |
2941 | { | |
2942 | *where = c2; | |
2943 | return bb2; | |
2944 | } | |
2945 | ||
2946 | if (!bb2) | |
2947 | { | |
2948 | *where = c1; | |
2949 | return bb1; | |
2950 | } | |
2951 | ||
2952 | ncd = nearest_common_dominator (CDI_DOMINATORS, bb1, bb2); | |
2953 | ||
2954 | /* If both candidates are in the same block, the earlier | |
2955 | candidate wins. */ | |
2956 | if (bb1 == ncd && bb2 == ncd) | |
2957 | { | |
2958 | if (!c1 || (c2 && c2->cand_num < c1->cand_num)) | |
2959 | *where = c2; | |
2960 | else | |
2961 | *where = c1; | |
2962 | } | |
2963 | ||
2964 | /* Otherwise, if one of them produced a candidate in the | |
2965 | dominator, that one wins. */ | |
2966 | else if (bb1 == ncd) | |
2967 | *where = c1; | |
2968 | ||
2969 | else if (bb2 == ncd) | |
2970 | *where = c2; | |
2971 | ||
2972 | /* If neither matches the dominator, neither wins. */ | |
2973 | else | |
2974 | *where = NULL; | |
2975 | ||
2976 | return ncd; | |
2977 | } | |
2978 | ||
9b92d12b BS |
2979 | /* Consider all candidates that feed PHI. Find the nearest common |
2980 | dominator of those candidates requiring the given increment INCR. | |
2981 | Further find and return the nearest common dominator of this result | |
2982 | with block NCD. If the returned block contains one or more of the | |
2983 | candidates, return the earliest candidate in the block in *WHERE. */ | |
2984 | ||
2985 | static basic_block | |
2986 | ncd_with_phi (slsr_cand_t c, double_int incr, gimple phi, | |
2987 | basic_block ncd, slsr_cand_t *where) | |
2988 | { | |
2989 | unsigned i; | |
2990 | slsr_cand_t basis = lookup_cand (c->basis); | |
2991 | slsr_cand_t phi_cand = base_cand_from_table (gimple_phi_result (phi)); | |
2992 | ||
2993 | for (i = 0; i < gimple_phi_num_args (phi); i++) | |
2994 | { | |
2995 | tree arg = gimple_phi_arg_def (phi, i); | |
2996 | ||
2997 | if (!operand_equal_p (arg, phi_cand->base_expr, 0)) | |
2998 | { | |
2999 | gimple arg_def = SSA_NAME_DEF_STMT (arg); | |
3000 | ||
3001 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
3002 | ncd = ncd_with_phi (c, incr, arg_def, ncd, where); | |
3003 | else | |
3004 | { | |
3005 | slsr_cand_t arg_cand = base_cand_from_table (arg); | |
3006 | double_int diff = arg_cand->index - basis->index; | |
1e386bb8 | 3007 | basic_block pred = gimple_phi_arg_edge (phi, i)->src; |
9b92d12b BS |
3008 | |
3009 | if ((incr == diff) || (!address_arithmetic_p && incr == -diff)) | |
1e386bb8 | 3010 | ncd = ncd_for_two_cands (ncd, pred, *where, NULL, where); |
9b92d12b BS |
3011 | } |
3012 | } | |
3013 | } | |
3014 | ||
3015 | return ncd; | |
3016 | } | |
3017 | ||
3018 | /* Consider the candidate C together with any candidates that feed | |
3019 | C's phi dependence (if any). Find and return the nearest common | |
3020 | dominator of those candidates requiring the given increment INCR. | |
3021 | If the returned block contains one or more of the candidates, | |
3022 | return the earliest candidate in the block in *WHERE. */ | |
3023 | ||
3024 | static basic_block | |
3025 | ncd_of_cand_and_phis (slsr_cand_t c, double_int incr, slsr_cand_t *where) | |
3026 | { | |
3027 | basic_block ncd = NULL; | |
3028 | ||
3029 | if (cand_abs_increment (c) == incr) | |
3030 | { | |
3031 | ncd = gimple_bb (c->cand_stmt); | |
3032 | *where = c; | |
3033 | } | |
3034 | ||
3035 | if (phi_dependent_cand_p (c)) | |
3036 | ncd = ncd_with_phi (c, incr, lookup_cand (c->def_phi)->cand_stmt, | |
3037 | ncd, where); | |
3038 | ||
3039 | return ncd; | |
3040 | } | |
3041 | ||
88ca9ea1 BS |
3042 | /* Consider all candidates in the tree rooted at C for which INCR |
3043 | represents the required increment of C relative to its basis. | |
3044 | Find and return the basic block that most nearly dominates all | |
3045 | such candidates. If the returned block contains one or more of | |
3046 | the candidates, return the earliest candidate in the block in | |
3047 | *WHERE. */ | |
3048 | ||
3049 | static basic_block | |
3050 | nearest_common_dominator_for_cands (slsr_cand_t c, double_int incr, | |
3051 | slsr_cand_t *where) | |
3052 | { | |
3053 | basic_block sib_ncd = NULL, dep_ncd = NULL, this_ncd = NULL, ncd; | |
3054 | slsr_cand_t sib_where = NULL, dep_where = NULL, this_where = NULL, new_where; | |
88ca9ea1 BS |
3055 | |
3056 | /* First find the NCD of all siblings and dependents. */ | |
3057 | if (c->sibling) | |
3058 | sib_ncd = nearest_common_dominator_for_cands (lookup_cand (c->sibling), | |
3059 | incr, &sib_where); | |
3060 | if (c->dependent) | |
3061 | dep_ncd = nearest_common_dominator_for_cands (lookup_cand (c->dependent), | |
3062 | incr, &dep_where); | |
3063 | if (!sib_ncd && !dep_ncd) | |
3064 | { | |
3065 | new_where = NULL; | |
3066 | ncd = NULL; | |
3067 | } | |
3068 | else if (sib_ncd && !dep_ncd) | |
3069 | { | |
3070 | new_where = sib_where; | |
3071 | ncd = sib_ncd; | |
3072 | } | |
3073 | else if (dep_ncd && !sib_ncd) | |
3074 | { | |
3075 | new_where = dep_where; | |
3076 | ncd = dep_ncd; | |
3077 | } | |
3078 | else | |
3079 | ncd = ncd_for_two_cands (sib_ncd, dep_ncd, sib_where, | |
3080 | dep_where, &new_where); | |
3081 | ||
3082 | /* If the candidate's increment doesn't match the one we're interested | |
9b92d12b BS |
3083 | in (and nor do any increments for feeding defs of a phi-dependence), |
3084 | then the result depends only on siblings and dependents. */ | |
3085 | this_ncd = ncd_of_cand_and_phis (c, incr, &this_where); | |
88ca9ea1 | 3086 | |
9b92d12b | 3087 | if (!this_ncd || cand_already_replaced (c)) |
88ca9ea1 BS |
3088 | { |
3089 | *where = new_where; | |
3090 | return ncd; | |
3091 | } | |
3092 | ||
3093 | /* Otherwise, compare this candidate with the result from all siblings | |
3094 | and dependents. */ | |
88ca9ea1 BS |
3095 | ncd = ncd_for_two_cands (ncd, this_ncd, new_where, this_where, where); |
3096 | ||
3097 | return ncd; | |
3098 | } | |
3099 | ||
3100 | /* Return TRUE if the increment indexed by INDEX is profitable to replace. */ | |
3101 | ||
3102 | static inline bool | |
3103 | profitable_increment_p (unsigned index) | |
3104 | { | |
3105 | return (incr_vec[index].cost <= COST_NEUTRAL); | |
3106 | } | |
3107 | ||
3108 | /* For each profitable increment in the increment vector not equal to | |
3109 | 0 or 1 (or -1, for non-pointer arithmetic), find the nearest common | |
3110 | dominator of all statements in the candidate chain rooted at C | |
3111 | that require that increment, and insert an initializer | |
3112 | T_0 = stride * increment at that location. Record T_0 with the | |
3113 | increment record. */ | |
3114 | ||
3115 | static void | |
3116 | insert_initializers (slsr_cand_t c) | |
3117 | { | |
3118 | unsigned i; | |
88ca9ea1 BS |
3119 | |
3120 | for (i = 0; i < incr_vec_len; i++) | |
3121 | { | |
3122 | basic_block bb; | |
3123 | slsr_cand_t where = NULL; | |
3124 | gimple init_stmt; | |
3125 | tree stride_type, new_name, incr_tree; | |
3126 | double_int incr = incr_vec[i].incr; | |
3127 | ||
3128 | if (!profitable_increment_p (i) | |
27bcd47c LC |
3129 | || incr.is_one () |
3130 | || (incr.is_minus_one () | |
88ca9ea1 | 3131 | && gimple_assign_rhs_code (c->cand_stmt) != POINTER_PLUS_EXPR) |
27bcd47c | 3132 | || incr.is_zero ()) |
88ca9ea1 BS |
3133 | continue; |
3134 | ||
3135 | /* We may have already identified an existing initializer that | |
3136 | will suffice. */ | |
3137 | if (incr_vec[i].initializer) | |
3138 | { | |
3139 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3140 | { | |
3141 | fputs ("Using existing initializer: ", dump_file); | |
3142 | print_gimple_stmt (dump_file, | |
3143 | SSA_NAME_DEF_STMT (incr_vec[i].initializer), | |
3144 | 0, 0); | |
3145 | } | |
3146 | continue; | |
3147 | } | |
3148 | ||
3149 | /* Find the block that most closely dominates all candidates | |
3150 | with this increment. If there is at least one candidate in | |
3151 | that block, the earliest one will be returned in WHERE. */ | |
3152 | bb = nearest_common_dominator_for_cands (c, incr, &where); | |
3153 | ||
3154 | /* Create a new SSA name to hold the initializer's value. */ | |
3155 | stride_type = TREE_TYPE (c->stride); | |
a7a7d10e | 3156 | new_name = make_temp_ssa_name (stride_type, NULL, "slsr"); |
88ca9ea1 BS |
3157 | incr_vec[i].initializer = new_name; |
3158 | ||
3159 | /* Create the initializer and insert it in the latest possible | |
3160 | dominating position. */ | |
3161 | incr_tree = double_int_to_tree (stride_type, incr); | |
3162 | init_stmt = gimple_build_assign_with_ops (MULT_EXPR, new_name, | |
3163 | c->stride, incr_tree); | |
3164 | if (where) | |
3165 | { | |
3166 | gimple_stmt_iterator gsi = gsi_for_stmt (where->cand_stmt); | |
3167 | gsi_insert_before (&gsi, init_stmt, GSI_SAME_STMT); | |
3168 | gimple_set_location (init_stmt, gimple_location (where->cand_stmt)); | |
3169 | } | |
3170 | else | |
3171 | { | |
3172 | gimple_stmt_iterator gsi = gsi_last_bb (bb); | |
3173 | gimple basis_stmt = lookup_cand (c->basis)->cand_stmt; | |
3174 | ||
3175 | if (!gsi_end_p (gsi) && is_ctrl_stmt (gsi_stmt (gsi))) | |
3176 | gsi_insert_before (&gsi, init_stmt, GSI_SAME_STMT); | |
3177 | else | |
3178 | gsi_insert_after (&gsi, init_stmt, GSI_SAME_STMT); | |
3179 | ||
3180 | gimple_set_location (init_stmt, gimple_location (basis_stmt)); | |
3181 | } | |
3182 | ||
3183 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3184 | { | |
3185 | fputs ("Inserting initializer: ", dump_file); | |
3186 | print_gimple_stmt (dump_file, init_stmt, 0, 0); | |
3187 | } | |
3188 | } | |
3189 | } | |
3190 | ||
9b92d12b BS |
3191 | /* Return TRUE iff all required increments for candidates feeding PHI |
3192 | are profitable to replace on behalf of candidate C. */ | |
3193 | ||
3194 | static bool | |
3195 | all_phi_incrs_profitable (slsr_cand_t c, gimple phi) | |
3196 | { | |
3197 | unsigned i; | |
3198 | slsr_cand_t basis = lookup_cand (c->basis); | |
3199 | slsr_cand_t phi_cand = base_cand_from_table (gimple_phi_result (phi)); | |
3200 | ||
3201 | for (i = 0; i < gimple_phi_num_args (phi); i++) | |
3202 | { | |
3203 | tree arg = gimple_phi_arg_def (phi, i); | |
3204 | ||
3205 | if (!operand_equal_p (arg, phi_cand->base_expr, 0)) | |
3206 | { | |
3207 | gimple arg_def = SSA_NAME_DEF_STMT (arg); | |
3208 | ||
3209 | if (gimple_code (arg_def) == GIMPLE_PHI) | |
3210 | { | |
3211 | if (!all_phi_incrs_profitable (c, arg_def)) | |
3212 | return false; | |
3213 | } | |
3214 | else | |
3215 | { | |
7bf55a70 | 3216 | int j; |
9b92d12b BS |
3217 | slsr_cand_t arg_cand = base_cand_from_table (arg); |
3218 | double_int increment = arg_cand->index - basis->index; | |
3219 | ||
3220 | if (!address_arithmetic_p && increment.is_negative ()) | |
3221 | increment = -increment; | |
3222 | ||
3223 | j = incr_vec_index (increment); | |
3224 | ||
3225 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3226 | { | |
3227 | fprintf (dump_file, " Conditional candidate %d, phi: ", | |
3228 | c->cand_num); | |
3229 | print_gimple_stmt (dump_file, phi, 0, 0); | |
3230 | fputs (" increment: ", dump_file); | |
3231 | dump_double_int (dump_file, increment, false); | |
7bf55a70 BS |
3232 | if (j < 0) |
3233 | fprintf (dump_file, | |
3234 | "\n Not replaced; incr_vec overflow.\n"); | |
3235 | else { | |
3236 | fprintf (dump_file, "\n cost: %d\n", incr_vec[j].cost); | |
3237 | if (profitable_increment_p (j)) | |
3238 | fputs (" Replacing...\n", dump_file); | |
3239 | else | |
3240 | fputs (" Not replaced.\n", dump_file); | |
3241 | } | |
9b92d12b BS |
3242 | } |
3243 | ||
7bf55a70 | 3244 | if (j < 0 || !profitable_increment_p (j)) |
9b92d12b BS |
3245 | return false; |
3246 | } | |
3247 | } | |
3248 | } | |
3249 | ||
3250 | return true; | |
3251 | } | |
3252 | ||
88ca9ea1 BS |
3253 | /* Create a NOP_EXPR that copies FROM_EXPR into a new SSA name of |
3254 | type TO_TYPE, and insert it in front of the statement represented | |
3255 | by candidate C. Use *NEW_VAR to create the new SSA name. Return | |
3256 | the new SSA name. */ | |
3257 | ||
3258 | static tree | |
a7a7d10e | 3259 | introduce_cast_before_cand (slsr_cand_t c, tree to_type, tree from_expr) |
88ca9ea1 BS |
3260 | { |
3261 | tree cast_lhs; | |
3262 | gimple cast_stmt; | |
3263 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
3264 | ||
a7a7d10e | 3265 | cast_lhs = make_temp_ssa_name (to_type, NULL, "slsr"); |
88ca9ea1 BS |
3266 | cast_stmt = gimple_build_assign_with_ops (NOP_EXPR, cast_lhs, |
3267 | from_expr, NULL_TREE); | |
3268 | gimple_set_location (cast_stmt, gimple_location (c->cand_stmt)); | |
3269 | gsi_insert_before (&gsi, cast_stmt, GSI_SAME_STMT); | |
3270 | ||
3271 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3272 | { | |
3273 | fputs (" Inserting: ", dump_file); | |
3274 | print_gimple_stmt (dump_file, cast_stmt, 0, 0); | |
3275 | } | |
3276 | ||
3277 | return cast_lhs; | |
3278 | } | |
3279 | ||
3280 | /* Replace the RHS of the statement represented by candidate C with | |
3281 | NEW_CODE, NEW_RHS1, and NEW_RHS2, provided that to do so doesn't | |
3282 | leave C unchanged or just interchange its operands. The original | |
3283 | operation and operands are in OLD_CODE, OLD_RHS1, and OLD_RHS2. | |
3284 | If the replacement was made and we are doing a details dump, | |
3285 | return the revised statement, else NULL. */ | |
3286 | ||
3287 | static gimple | |
3288 | replace_rhs_if_not_dup (enum tree_code new_code, tree new_rhs1, tree new_rhs2, | |
3289 | enum tree_code old_code, tree old_rhs1, tree old_rhs2, | |
3290 | slsr_cand_t c) | |
3291 | { | |
3292 | if (new_code != old_code | |
3293 | || ((!operand_equal_p (new_rhs1, old_rhs1, 0) | |
3294 | || !operand_equal_p (new_rhs2, old_rhs2, 0)) | |
3295 | && (!operand_equal_p (new_rhs1, old_rhs2, 0) | |
3296 | || !operand_equal_p (new_rhs2, old_rhs1, 0)))) | |
3297 | { | |
3298 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
3299 | gimple_assign_set_rhs_with_ops (&gsi, new_code, new_rhs1, new_rhs2); | |
3300 | update_stmt (gsi_stmt (gsi)); | |
bb0d2039 | 3301 | c->cand_stmt = gsi_stmt (gsi); |
88ca9ea1 BS |
3302 | |
3303 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3304 | return gsi_stmt (gsi); | |
3305 | } | |
3306 | ||
3307 | else if (dump_file && (dump_flags & TDF_DETAILS)) | |
3308 | fputs (" (duplicate, not actually replacing)\n", dump_file); | |
3309 | ||
3310 | return NULL; | |
3311 | } | |
3312 | ||
3313 | /* Strength-reduce the statement represented by candidate C by replacing | |
3314 | it with an equivalent addition or subtraction. I is the index into | |
3315 | the increment vector identifying C's increment. NEW_VAR is used to | |
3316 | create a new SSA name if a cast needs to be introduced. BASIS_NAME | |
3317 | is the rhs1 to use in creating the add/subtract. */ | |
3318 | ||
3319 | static void | |
a7a7d10e | 3320 | replace_one_candidate (slsr_cand_t c, unsigned i, tree basis_name) |
88ca9ea1 BS |
3321 | { |
3322 | gimple stmt_to_print = NULL; | |
3323 | tree orig_rhs1, orig_rhs2; | |
3324 | tree rhs2; | |
3325 | enum tree_code orig_code, repl_code; | |
3326 | double_int cand_incr; | |
3327 | ||
3328 | orig_code = gimple_assign_rhs_code (c->cand_stmt); | |
3329 | orig_rhs1 = gimple_assign_rhs1 (c->cand_stmt); | |
3330 | orig_rhs2 = gimple_assign_rhs2 (c->cand_stmt); | |
3331 | cand_incr = cand_increment (c); | |
3332 | ||
3333 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3334 | { | |
3335 | fputs ("Replacing: ", dump_file); | |
3336 | print_gimple_stmt (dump_file, c->cand_stmt, 0, 0); | |
3337 | stmt_to_print = c->cand_stmt; | |
3338 | } | |
3339 | ||
3340 | if (address_arithmetic_p) | |
3341 | repl_code = POINTER_PLUS_EXPR; | |
3342 | else | |
3343 | repl_code = PLUS_EXPR; | |
3344 | ||
3345 | /* If the increment has an initializer T_0, replace the candidate | |
3346 | statement with an add of the basis name and the initializer. */ | |
3347 | if (incr_vec[i].initializer) | |
3348 | { | |
3349 | tree init_type = TREE_TYPE (incr_vec[i].initializer); | |
3350 | tree orig_type = TREE_TYPE (orig_rhs2); | |
3351 | ||
3352 | if (types_compatible_p (orig_type, init_type)) | |
3353 | rhs2 = incr_vec[i].initializer; | |
3354 | else | |
3355 | rhs2 = introduce_cast_before_cand (c, orig_type, | |
a7a7d10e | 3356 | incr_vec[i].initializer); |
88ca9ea1 | 3357 | |
27bcd47c | 3358 | if (incr_vec[i].incr != cand_incr) |
88ca9ea1 BS |
3359 | { |
3360 | gcc_assert (repl_code == PLUS_EXPR); | |
3361 | repl_code = MINUS_EXPR; | |
3362 | } | |
3363 | ||
3364 | stmt_to_print = replace_rhs_if_not_dup (repl_code, basis_name, rhs2, | |
3365 | orig_code, orig_rhs1, orig_rhs2, | |
3366 | c); | |
3367 | } | |
3368 | ||
3369 | /* Otherwise, the increment is one of -1, 0, and 1. Replace | |
3370 | with a subtract of the stride from the basis name, a copy | |
3371 | from the basis name, or an add of the stride to the basis | |
3372 | name, respectively. It may be necessary to introduce a | |
3373 | cast (or reuse an existing cast). */ | |
27bcd47c | 3374 | else if (cand_incr.is_one ()) |
88ca9ea1 BS |
3375 | { |
3376 | tree stride_type = TREE_TYPE (c->stride); | |
3377 | tree orig_type = TREE_TYPE (orig_rhs2); | |
3378 | ||
3379 | if (types_compatible_p (orig_type, stride_type)) | |
3380 | rhs2 = c->stride; | |
3381 | else | |
a7a7d10e | 3382 | rhs2 = introduce_cast_before_cand (c, orig_type, c->stride); |
88ca9ea1 BS |
3383 | |
3384 | stmt_to_print = replace_rhs_if_not_dup (repl_code, basis_name, rhs2, | |
3385 | orig_code, orig_rhs1, orig_rhs2, | |
3386 | c); | |
3387 | } | |
3388 | ||
27bcd47c | 3389 | else if (cand_incr.is_minus_one ()) |
88ca9ea1 BS |
3390 | { |
3391 | tree stride_type = TREE_TYPE (c->stride); | |
3392 | tree orig_type = TREE_TYPE (orig_rhs2); | |
3393 | gcc_assert (repl_code != POINTER_PLUS_EXPR); | |
3394 | ||
3395 | if (types_compatible_p (orig_type, stride_type)) | |
3396 | rhs2 = c->stride; | |
3397 | else | |
a7a7d10e | 3398 | rhs2 = introduce_cast_before_cand (c, orig_type, c->stride); |
88ca9ea1 BS |
3399 | |
3400 | if (orig_code != MINUS_EXPR | |
3401 | || !operand_equal_p (basis_name, orig_rhs1, 0) | |
3402 | || !operand_equal_p (rhs2, orig_rhs2, 0)) | |
3403 | { | |
3404 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
3405 | gimple_assign_set_rhs_with_ops (&gsi, MINUS_EXPR, basis_name, rhs2); | |
3406 | update_stmt (gsi_stmt (gsi)); | |
bb0d2039 | 3407 | c->cand_stmt = gsi_stmt (gsi); |
88ca9ea1 BS |
3408 | |
3409 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3410 | stmt_to_print = gsi_stmt (gsi); | |
3411 | } | |
3412 | else if (dump_file && (dump_flags & TDF_DETAILS)) | |
3413 | fputs (" (duplicate, not actually replacing)\n", dump_file); | |
3414 | } | |
3415 | ||
27bcd47c | 3416 | else if (cand_incr.is_zero ()) |
88ca9ea1 BS |
3417 | { |
3418 | tree lhs = gimple_assign_lhs (c->cand_stmt); | |
3419 | tree lhs_type = TREE_TYPE (lhs); | |
3420 | tree basis_type = TREE_TYPE (basis_name); | |
3421 | ||
3422 | if (types_compatible_p (lhs_type, basis_type)) | |
3423 | { | |
3424 | gimple copy_stmt = gimple_build_assign (lhs, basis_name); | |
3425 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
3426 | gimple_set_location (copy_stmt, gimple_location (c->cand_stmt)); | |
3427 | gsi_replace (&gsi, copy_stmt, false); | |
0100cd3f | 3428 | c->cand_stmt = copy_stmt; |
88ca9ea1 BS |
3429 | |
3430 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3431 | stmt_to_print = copy_stmt; | |
3432 | } | |
3433 | else | |
3434 | { | |
3435 | gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt); | |
3436 | gimple cast_stmt = gimple_build_assign_with_ops (NOP_EXPR, lhs, | |
3437 | basis_name, | |
3438 | NULL_TREE); | |
3439 | gimple_set_location (cast_stmt, gimple_location (c->cand_stmt)); | |
3440 | gsi_replace (&gsi, cast_stmt, false); | |
0100cd3f | 3441 | c->cand_stmt = cast_stmt; |
88ca9ea1 BS |
3442 | |
3443 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3444 | stmt_to_print = cast_stmt; | |
3445 | } | |
3446 | } | |
3447 | else | |
3448 | gcc_unreachable (); | |
3449 | ||
3450 | if (dump_file && (dump_flags & TDF_DETAILS) && stmt_to_print) | |
3451 | { | |
3452 | fputs ("With: ", dump_file); | |
3453 | print_gimple_stmt (dump_file, stmt_to_print, 0, 0); | |
3454 | fputs ("\n", dump_file); | |
3455 | } | |
3456 | } | |
3457 | ||
3458 | /* For each candidate in the tree rooted at C, replace it with | |
3459 | an increment if such has been shown to be profitable. */ | |
3460 | ||
3461 | static void | |
3462 | replace_profitable_candidates (slsr_cand_t c) | |
3463 | { | |
3464 | if (!cand_already_replaced (c)) | |
3465 | { | |
3466 | double_int increment = cand_abs_increment (c); | |
88ca9ea1 | 3467 | enum tree_code orig_code = gimple_assign_rhs_code (c->cand_stmt); |
7bf55a70 | 3468 | int i; |
88ca9ea1 BS |
3469 | |
3470 | i = incr_vec_index (increment); | |
3471 | ||
3472 | /* Only process profitable increments. Nothing useful can be done | |
3473 | to a cast or copy. */ | |
7bf55a70 BS |
3474 | if (i >= 0 |
3475 | && profitable_increment_p (i) | |
88ca9ea1 BS |
3476 | && orig_code != MODIFY_EXPR |
3477 | && orig_code != NOP_EXPR) | |
3478 | { | |
9b92d12b BS |
3479 | if (phi_dependent_cand_p (c)) |
3480 | { | |
3481 | gimple phi = lookup_cand (c->def_phi)->cand_stmt; | |
3482 | ||
3483 | if (all_phi_incrs_profitable (c, phi)) | |
3484 | { | |
3485 | /* Look up the LHS SSA name from C's basis. This will be | |
3486 | the RHS1 of the adds we will introduce to create new | |
3487 | phi arguments. */ | |
3488 | slsr_cand_t basis = lookup_cand (c->basis); | |
3489 | tree basis_name = gimple_assign_lhs (basis->cand_stmt); | |
3490 | ||
3491 | /* Create a new phi statement that will represent C's true | |
3492 | basis after the transformation is complete. */ | |
3493 | location_t loc = gimple_location (c->cand_stmt); | |
3494 | tree name = create_phi_basis (c, phi, basis_name, | |
3495 | loc, UNKNOWN_STRIDE); | |
3496 | ||
3497 | /* Replace C with an add of the new basis phi and the | |
3498 | increment. */ | |
a7a7d10e | 3499 | replace_one_candidate (c, i, name); |
9b92d12b BS |
3500 | } |
3501 | } | |
3502 | else | |
3503 | { | |
3504 | slsr_cand_t basis = lookup_cand (c->basis); | |
3505 | tree basis_name = gimple_assign_lhs (basis->cand_stmt); | |
a7a7d10e | 3506 | replace_one_candidate (c, i, basis_name); |
9b92d12b | 3507 | } |
88ca9ea1 BS |
3508 | } |
3509 | } | |
3510 | ||
3511 | if (c->sibling) | |
3512 | replace_profitable_candidates (lookup_cand (c->sibling)); | |
3513 | ||
3514 | if (c->dependent) | |
3515 | replace_profitable_candidates (lookup_cand (c->dependent)); | |
3516 | } | |
3517 | \f | |
f9453c07 BS |
3518 | /* Analyze costs of related candidates in the candidate vector, |
3519 | and make beneficial replacements. */ | |
3520 | ||
3521 | static void | |
3522 | analyze_candidates_and_replace (void) | |
3523 | { | |
3524 | unsigned i; | |
3525 | slsr_cand_t c; | |
3526 | ||
3527 | /* Each candidate that has a null basis and a non-null | |
3528 | dependent is the root of a tree of related statements. | |
3529 | Analyze each tree to determine a subset of those | |
3530 | statements that can be replaced with maximum benefit. */ | |
9771b263 | 3531 | FOR_EACH_VEC_ELT (cand_vec, i, c) |
f9453c07 BS |
3532 | { |
3533 | slsr_cand_t first_dep; | |
3534 | ||
3535 | if (c->basis != 0 || c->dependent == 0) | |
3536 | continue; | |
3537 | ||
3538 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3539 | fprintf (dump_file, "\nProcessing dependency tree rooted at %d.\n", | |
3540 | c->cand_num); | |
3541 | ||
3542 | first_dep = lookup_cand (c->dependent); | |
3543 | ||
2749c8f6 BS |
3544 | /* If this is a chain of CAND_REFs, unconditionally replace |
3545 | each of them with a strength-reduced data reference. */ | |
3546 | if (c->kind == CAND_REF) | |
3547 | replace_refs (c); | |
3548 | ||
9b92d12b BS |
3549 | /* If the common stride of all related candidates is a known |
3550 | constant, each candidate without a phi-dependence can be | |
3551 | profitably replaced. Each replaces a multiply by a single | |
3552 | add, with the possibility that a feeding add also goes dead. | |
3553 | A candidate with a phi-dependence is replaced only if the | |
3554 | compensation code it requires is offset by the strength | |
3555 | reduction savings. */ | |
3556 | else if (TREE_CODE (c->stride) == INTEGER_CST) | |
3557 | replace_uncond_cands_and_profitable_phis (first_dep); | |
f9453c07 | 3558 | |
88ca9ea1 BS |
3559 | /* When the stride is an SSA name, it may still be profitable |
3560 | to replace some or all of the dependent candidates, depending | |
3561 | on whether the introduced increments can be reused, or are | |
3562 | less expensive to calculate than the replaced statements. */ | |
3563 | else | |
3564 | { | |
88ca9ea1 BS |
3565 | enum machine_mode mode; |
3566 | bool speed; | |
3567 | ||
3568 | /* Determine whether we'll be generating pointer arithmetic | |
3569 | when replacing candidates. */ | |
3570 | address_arithmetic_p = (c->kind == CAND_ADD | |
99cababb | 3571 | && POINTER_TYPE_P (c->cand_type)); |
88ca9ea1 BS |
3572 | |
3573 | /* If all candidates have already been replaced under other | |
3574 | interpretations, nothing remains to be done. */ | |
4b847da9 | 3575 | if (!count_candidates (c)) |
88ca9ea1 BS |
3576 | continue; |
3577 | ||
3578 | /* Construct an array of increments for this candidate chain. */ | |
4b847da9 | 3579 | incr_vec = XNEWVEC (incr_info, MAX_INCR_VEC_LEN); |
88ca9ea1 BS |
3580 | incr_vec_len = 0; |
3581 | record_increments (c); | |
3582 | ||
3583 | /* Determine which increments are profitable to replace. */ | |
3584 | mode = TYPE_MODE (TREE_TYPE (gimple_assign_lhs (c->cand_stmt))); | |
3585 | speed = optimize_cands_for_speed_p (c); | |
3586 | analyze_increments (first_dep, mode, speed); | |
3587 | ||
3588 | /* Insert initializers of the form T_0 = stride * increment | |
3589 | for use in profitable replacements. */ | |
3590 | insert_initializers (first_dep); | |
3591 | dump_incr_vec (); | |
3592 | ||
3593 | /* Perform the replacements. */ | |
3594 | replace_profitable_candidates (first_dep); | |
3595 | free (incr_vec); | |
3596 | } | |
f9453c07 BS |
3597 | } |
3598 | } | |
3599 | ||
be55bfe6 TS |
3600 | namespace { |
3601 | ||
3602 | const pass_data pass_data_strength_reduction = | |
3603 | { | |
3604 | GIMPLE_PASS, /* type */ | |
3605 | "slsr", /* name */ | |
3606 | OPTGROUP_NONE, /* optinfo_flags */ | |
3607 | true, /* has_execute */ | |
3608 | TV_GIMPLE_SLSR, /* tv_id */ | |
3609 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
3610 | 0, /* properties_provided */ | |
3611 | 0, /* properties_destroyed */ | |
3612 | 0, /* todo_flags_start */ | |
3bea341f | 3613 | 0, /* todo_flags_finish */ |
be55bfe6 TS |
3614 | }; |
3615 | ||
3616 | class pass_strength_reduction : public gimple_opt_pass | |
3617 | { | |
3618 | public: | |
3619 | pass_strength_reduction (gcc::context *ctxt) | |
3620 | : gimple_opt_pass (pass_data_strength_reduction, ctxt) | |
3621 | {} | |
3622 | ||
3623 | /* opt_pass methods: */ | |
3624 | virtual bool gate (function *) { return flag_tree_slsr; } | |
3625 | virtual unsigned int execute (function *); | |
3626 | ||
3627 | }; // class pass_strength_reduction | |
3628 | ||
3629 | unsigned | |
3630 | pass_strength_reduction::execute (function *fun) | |
f9453c07 | 3631 | { |
f9453c07 BS |
3632 | /* Create the obstack where candidates will reside. */ |
3633 | gcc_obstack_init (&cand_obstack); | |
3634 | ||
3635 | /* Allocate the candidate vector. */ | |
9771b263 | 3636 | cand_vec.create (128); |
f9453c07 BS |
3637 | |
3638 | /* Allocate the mapping from statements to candidate indices. */ | |
3639 | stmt_cand_map = pointer_map_create (); | |
3640 | ||
3641 | /* Create the obstack where candidate chains will reside. */ | |
3642 | gcc_obstack_init (&chain_obstack); | |
3643 | ||
3cfd4469 | 3644 | /* Allocate the mapping from base expressions to candidate chains. */ |
4a8fb1a1 | 3645 | base_cand_map.create (500); |
f9453c07 | 3646 | |
96d75a2c YZ |
3647 | /* Allocate the mapping from bases to alternative bases. */ |
3648 | alt_base_map = pointer_map_create (); | |
3649 | ||
f9453c07 BS |
3650 | /* Initialize the loop optimizer. We need to detect flow across |
3651 | back edges, and this gives us dominator information as well. */ | |
3652 | loop_optimizer_init (AVOID_CFG_MODIFICATIONS); | |
3653 | ||
f9453c07 BS |
3654 | /* Walk the CFG in predominator order looking for strength reduction |
3655 | candidates. */ | |
4d9192b5 | 3656 | find_candidates_dom_walker (CDI_DOMINATORS) |
be55bfe6 | 3657 | .walk (fun->cfg->x_entry_block_ptr); |
f9453c07 BS |
3658 | |
3659 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3660 | { | |
3661 | dump_cand_vec (); | |
3662 | dump_cand_chains (); | |
3663 | } | |
3664 | ||
96d75a2c YZ |
3665 | pointer_map_destroy (alt_base_map); |
3666 | free_affine_expand_cache (&name_expansions); | |
3667 | ||
f9453c07 BS |
3668 | /* Analyze costs and make appropriate replacements. */ |
3669 | analyze_candidates_and_replace (); | |
3670 | ||
f9453c07 | 3671 | loop_optimizer_finalize (); |
4a8fb1a1 | 3672 | base_cand_map.dispose (); |
f9453c07 BS |
3673 | obstack_free (&chain_obstack, NULL); |
3674 | pointer_map_destroy (stmt_cand_map); | |
9771b263 | 3675 | cand_vec.release (); |
f9453c07 | 3676 | obstack_free (&cand_obstack, NULL); |
f9453c07 BS |
3677 | |
3678 | return 0; | |
3679 | } | |
3680 | ||
27a4cd48 DM |
3681 | } // anon namespace |
3682 | ||
3683 | gimple_opt_pass * | |
3684 | make_pass_strength_reduction (gcc::context *ctxt) | |
3685 | { | |
3686 | return new pass_strength_reduction (ctxt); | |
3687 | } |