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b9d73ea6 | 1 | /* Scalar evolution detector. |
3aea1f79 | 2 | Copyright (C) 2003-2014 Free Software Foundation, Inc. |
b9d73ea6 | 3 | Contributed by Sebastian Pop <s.pop@laposte.net> |
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 | |
8c4c00c1 | 9 | Software Foundation; either version 3, or (at your option) any later |
b9d73ea6 | 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 | |
8c4c00c1 | 18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ | |
b9d73ea6 | 20 | |
48e1416a | 21 | /* |
22 | Description: | |
23 | ||
c2c3fd24 | 24 | This pass analyzes the evolution of scalar variables in loop |
25 | structures. The algorithm is based on the SSA representation, | |
26 | and on the loop hierarchy tree. This algorithm is not based on | |
27 | the notion of versions of a variable, as it was the case for the | |
28 | previous implementations of the scalar evolution algorithm, but | |
29 | it assumes that each defined name is unique. | |
30 | ||
31 | The notation used in this file is called "chains of recurrences", | |
32 | and has been proposed by Eugene Zima, Robert Van Engelen, and | |
33 | others for describing induction variables in programs. For example | |
34 | "b -> {0, +, 2}_1" means that the scalar variable "b" is equal to 0 | |
35 | when entering in the loop_1 and has a step 2 in this loop, in other | |
36 | words "for (b = 0; b < N; b+=2);". Note that the coefficients of | |
37 | this chain of recurrence (or chrec [shrek]) can contain the name of | |
38 | other variables, in which case they are called parametric chrecs. | |
39 | For example, "b -> {a, +, 2}_1" means that the initial value of "b" | |
40 | is the value of "a". In most of the cases these parametric chrecs | |
41 | are fully instantiated before their use because symbolic names can | |
42 | hide some difficult cases such as self-references described later | |
43 | (see the Fibonacci example). | |
48e1416a | 44 | |
c2c3fd24 | 45 | A short sketch of the algorithm is: |
48e1416a | 46 | |
c2c3fd24 | 47 | Given a scalar variable to be analyzed, follow the SSA edge to |
48 | its definition: | |
48e1416a | 49 | |
75a70cf9 | 50 | - When the definition is a GIMPLE_ASSIGN: if the right hand side |
c2c3fd24 | 51 | (RHS) of the definition cannot be statically analyzed, the answer |
48e1416a | 52 | of the analyzer is: "don't know". |
c2c3fd24 | 53 | Otherwise, for all the variables that are not yet analyzed in the |
54 | RHS, try to determine their evolution, and finally try to | |
55 | evaluate the operation of the RHS that gives the evolution | |
56 | function of the analyzed variable. | |
57 | ||
58 | - When the definition is a condition-phi-node: determine the | |
59 | evolution function for all the branches of the phi node, and | |
60 | finally merge these evolutions (see chrec_merge). | |
61 | ||
62 | - When the definition is a loop-phi-node: determine its initial | |
63 | condition, that is the SSA edge defined in an outer loop, and | |
64 | keep it symbolic. Then determine the SSA edges that are defined | |
65 | in the body of the loop. Follow the inner edges until ending on | |
66 | another loop-phi-node of the same analyzed loop. If the reached | |
67 | loop-phi-node is not the starting loop-phi-node, then we keep | |
68 | this definition under a symbolic form. If the reached | |
69 | loop-phi-node is the same as the starting one, then we compute a | |
70 | symbolic stride on the return path. The result is then the | |
71 | symbolic chrec {initial_condition, +, symbolic_stride}_loop. | |
72 | ||
73 | Examples: | |
48e1416a | 74 | |
c2c3fd24 | 75 | Example 1: Illustration of the basic algorithm. |
48e1416a | 76 | |
c2c3fd24 | 77 | | a = 3 |
78 | | loop_1 | |
79 | | b = phi (a, c) | |
80 | | c = b + 1 | |
81 | | if (c > 10) exit_loop | |
82 | | endloop | |
48e1416a | 83 | |
c2c3fd24 | 84 | Suppose that we want to know the number of iterations of the |
85 | loop_1. The exit_loop is controlled by a COND_EXPR (c > 10). We | |
86 | ask the scalar evolution analyzer two questions: what's the | |
87 | scalar evolution (scev) of "c", and what's the scev of "10". For | |
88 | "10" the answer is "10" since it is a scalar constant. For the | |
89 | scalar variable "c", it follows the SSA edge to its definition, | |
90 | "c = b + 1", and then asks again what's the scev of "b". | |
91 | Following the SSA edge, we end on a loop-phi-node "b = phi (a, | |
92 | c)", where the initial condition is "a", and the inner loop edge | |
93 | is "c". The initial condition is kept under a symbolic form (it | |
94 | may be the case that the copy constant propagation has done its | |
95 | work and we end with the constant "3" as one of the edges of the | |
96 | loop-phi-node). The update edge is followed to the end of the | |
97 | loop, and until reaching again the starting loop-phi-node: b -> c | |
98 | -> b. At this point we have drawn a path from "b" to "b" from | |
99 | which we compute the stride in the loop: in this example it is | |
100 | "+1". The resulting scev for "b" is "b -> {a, +, 1}_1". Now | |
101 | that the scev for "b" is known, it is possible to compute the | |
102 | scev for "c", that is "c -> {a + 1, +, 1}_1". In order to | |
103 | determine the number of iterations in the loop_1, we have to | |
afd80ffb | 104 | instantiate_parameters (loop_1, {a + 1, +, 1}_1), that gives after some |
c2c3fd24 | 105 | more analysis the scev {4, +, 1}_1, or in other words, this is |
106 | the function "f (x) = x + 4", where x is the iteration count of | |
107 | the loop_1. Now we have to solve the inequality "x + 4 > 10", | |
108 | and take the smallest iteration number for which the loop is | |
109 | exited: x = 7. This loop runs from x = 0 to x = 7, and in total | |
110 | there are 8 iterations. In terms of loop normalization, we have | |
111 | created a variable that is implicitly defined, "x" or just "_1", | |
112 | and all the other analyzed scalars of the loop are defined in | |
113 | function of this variable: | |
48e1416a | 114 | |
c2c3fd24 | 115 | a -> 3 |
116 | b -> {3, +, 1}_1 | |
117 | c -> {4, +, 1}_1 | |
48e1416a | 118 | |
119 | or in terms of a C program: | |
120 | ||
c2c3fd24 | 121 | | a = 3 |
122 | | for (x = 0; x <= 7; x++) | |
123 | | { | |
124 | | b = x + 3 | |
125 | | c = x + 4 | |
126 | | } | |
48e1416a | 127 | |
afd80ffb | 128 | Example 2a: Illustration of the algorithm on nested loops. |
48e1416a | 129 | |
c2c3fd24 | 130 | | loop_1 |
131 | | a = phi (1, b) | |
132 | | c = a + 2 | |
133 | | loop_2 10 times | |
134 | | b = phi (c, d) | |
135 | | d = b + 3 | |
136 | | endloop | |
137 | | endloop | |
48e1416a | 138 | |
c2c3fd24 | 139 | For analyzing the scalar evolution of "a", the algorithm follows |
140 | the SSA edge into the loop's body: "a -> b". "b" is an inner | |
48e1416a | 141 | loop-phi-node, and its analysis as in Example 1, gives: |
142 | ||
c2c3fd24 | 143 | b -> {c, +, 3}_2 |
144 | d -> {c + 3, +, 3}_2 | |
48e1416a | 145 | |
c2c3fd24 | 146 | Following the SSA edge for the initial condition, we end on "c = a |
147 | + 2", and then on the starting loop-phi-node "a". From this point, | |
148 | the loop stride is computed: back on "c = a + 2" we get a "+2" in | |
149 | the loop_1, then on the loop-phi-node "b" we compute the overall | |
150 | effect of the inner loop that is "b = c + 30", and we get a "+30" | |
151 | in the loop_1. That means that the overall stride in loop_1 is | |
48e1416a | 152 | equal to "+32", and the result is: |
153 | ||
c2c3fd24 | 154 | a -> {1, +, 32}_1 |
155 | c -> {3, +, 32}_1 | |
afd80ffb | 156 | |
157 | Example 2b: Multivariate chains of recurrences. | |
158 | ||
159 | | loop_1 | |
160 | | k = phi (0, k + 1) | |
161 | | loop_2 4 times | |
162 | | j = phi (0, j + 1) | |
163 | | loop_3 4 times | |
164 | | i = phi (0, i + 1) | |
165 | | A[j + k] = ... | |
166 | | endloop | |
167 | | endloop | |
168 | | endloop | |
169 | ||
170 | Analyzing the access function of array A with | |
171 | instantiate_parameters (loop_1, "j + k"), we obtain the | |
172 | instantiation and the analysis of the scalar variables "j" and "k" | |
173 | in loop_1. This leads to the scalar evolution {4, +, 1}_1: the end | |
174 | value of loop_2 for "j" is 4, and the evolution of "k" in loop_1 is | |
175 | {0, +, 1}_1. To obtain the evolution function in loop_3 and | |
176 | instantiate the scalar variables up to loop_1, one has to use: | |
089aa668 | 177 | instantiate_scev (block_before_loop (loop_1), loop_3, "j + k"). |
178 | The result of this call is {{0, +, 1}_1, +, 1}_2. | |
afd80ffb | 179 | |
c2c3fd24 | 180 | Example 3: Higher degree polynomials. |
48e1416a | 181 | |
c2c3fd24 | 182 | | loop_1 |
183 | | a = phi (2, b) | |
184 | | c = phi (5, d) | |
185 | | b = a + 1 | |
186 | | d = c + a | |
187 | | endloop | |
48e1416a | 188 | |
c2c3fd24 | 189 | a -> {2, +, 1}_1 |
190 | b -> {3, +, 1}_1 | |
191 | c -> {5, +, a}_1 | |
192 | d -> {5 + a, +, a}_1 | |
48e1416a | 193 | |
afd80ffb | 194 | instantiate_parameters (loop_1, {5, +, a}_1) -> {5, +, 2, +, 1}_1 |
195 | instantiate_parameters (loop_1, {5 + a, +, a}_1) -> {7, +, 3, +, 1}_1 | |
48e1416a | 196 | |
c2c3fd24 | 197 | Example 4: Lucas, Fibonacci, or mixers in general. |
48e1416a | 198 | |
c2c3fd24 | 199 | | loop_1 |
200 | | a = phi (1, b) | |
201 | | c = phi (3, d) | |
202 | | b = c | |
203 | | d = c + a | |
204 | | endloop | |
48e1416a | 205 | |
c2c3fd24 | 206 | a -> (1, c)_1 |
207 | c -> {3, +, a}_1 | |
48e1416a | 208 | |
c2c3fd24 | 209 | The syntax "(1, c)_1" stands for a PEELED_CHREC that has the |
210 | following semantics: during the first iteration of the loop_1, the | |
211 | variable contains the value 1, and then it contains the value "c". | |
212 | Note that this syntax is close to the syntax of the loop-phi-node: | |
213 | "a -> (1, c)_1" vs. "a = phi (1, c)". | |
48e1416a | 214 | |
c2c3fd24 | 215 | The symbolic chrec representation contains all the semantics of the |
216 | original code. What is more difficult is to use this information. | |
48e1416a | 217 | |
c2c3fd24 | 218 | Example 5: Flip-flops, or exchangers. |
48e1416a | 219 | |
c2c3fd24 | 220 | | loop_1 |
221 | | a = phi (1, b) | |
222 | | c = phi (3, d) | |
223 | | b = c | |
224 | | d = a | |
225 | | endloop | |
48e1416a | 226 | |
c2c3fd24 | 227 | a -> (1, c)_1 |
228 | c -> (3, a)_1 | |
48e1416a | 229 | |
c2c3fd24 | 230 | Based on these symbolic chrecs, it is possible to refine this |
48e1416a | 231 | information into the more precise PERIODIC_CHRECs: |
232 | ||
c2c3fd24 | 233 | a -> |1, 3|_1 |
234 | c -> |3, 1|_1 | |
48e1416a | 235 | |
c2c3fd24 | 236 | This transformation is not yet implemented. |
48e1416a | 237 | |
c2c3fd24 | 238 | Further readings: |
48e1416a | 239 | |
c2c3fd24 | 240 | You can find a more detailed description of the algorithm in: |
241 | http://icps.u-strasbg.fr/~pop/DEA_03_Pop.pdf | |
242 | http://icps.u-strasbg.fr/~pop/DEA_03_Pop.ps.gz. But note that | |
243 | this is a preliminary report and some of the details of the | |
244 | algorithm have changed. I'm working on a research report that | |
245 | updates the description of the algorithms to reflect the design | |
246 | choices used in this implementation. | |
48e1416a | 247 | |
c2c3fd24 | 248 | A set of slides show a high level overview of the algorithm and run |
249 | an example through the scalar evolution analyzer: | |
250 | http://cri.ensmp.fr/~pop/gcc/mar04/slides.pdf | |
251 | ||
252 | The slides that I have presented at the GCC Summit'04 are available | |
253 | at: http://cri.ensmp.fr/~pop/gcc/20040604/gccsummit-lno-spop.pdf | |
254 | */ | |
255 | ||
b9d73ea6 | 256 | #include "config.h" |
257 | #include "system.h" | |
258 | #include "coretypes.h" | |
0d9585ca | 259 | #include "tree.h" |
9ed99284 | 260 | #include "expr.h" |
ce084dfc | 261 | #include "gimple-pretty-print.h" |
94ea8568 | 262 | #include "predict.h" |
263 | #include "vec.h" | |
264 | #include "hashtab.h" | |
265 | #include "hash-set.h" | |
266 | #include "machmode.h" | |
267 | #include "tm.h" | |
268 | #include "hard-reg-set.h" | |
269 | #include "input.h" | |
270 | #include "function.h" | |
271 | #include "dominance.h" | |
272 | #include "cfg.h" | |
bc61cadb | 273 | #include "basic-block.h" |
274 | #include "tree-ssa-alias.h" | |
275 | #include "internal-fn.h" | |
276 | #include "gimple-expr.h" | |
277 | #include "is-a.h" | |
e795d6e1 | 278 | #include "gimple.h" |
a8783bee | 279 | #include "gimplify.h" |
dcf1a1ec | 280 | #include "gimple-iterator.h" |
e795d6e1 | 281 | #include "gimplify-me.h" |
073c1fd5 | 282 | #include "gimple-ssa.h" |
283 | #include "tree-cfg.h" | |
284 | #include "tree-phinodes.h" | |
9ed99284 | 285 | #include "stringpool.h" |
073c1fd5 | 286 | #include "tree-ssanames.h" |
05d9c18a | 287 | #include "tree-ssa-loop-ivopts.h" |
288 | #include "tree-ssa-loop-manip.h" | |
289 | #include "tree-ssa-loop-niter.h" | |
073c1fd5 | 290 | #include "tree-ssa-loop.h" |
69ee5dbb | 291 | #include "tree-ssa.h" |
b9d73ea6 | 292 | #include "cfgloop.h" |
293 | #include "tree-chrec.h" | |
c03531c4 | 294 | #include "tree-affine.h" |
b9d73ea6 | 295 | #include "tree-scalar-evolution.h" |
b9ed1410 | 296 | #include "dumpfile.h" |
d1de0ec2 | 297 | #include "params.h" |
0f4161b1 | 298 | #include "tree-ssa-propagate.h" |
f6a34e3f | 299 | #include "gimple-fold.h" |
300 | #include "gimplify-me.h" | |
c2c3fd24 | 301 | |
302 | static tree analyze_scalar_evolution_1 (struct loop *, tree, tree); | |
62bc06ea | 303 | static tree analyze_scalar_evolution_for_address_of (struct loop *loop, |
304 | tree var); | |
c2c3fd24 | 305 | |
cbb69ef1 | 306 | /* The cached information about an SSA name with version NAME_VERSION, |
307 | claiming that below basic block with index INSTANTIATED_BELOW, the | |
308 | value of the SSA name can be expressed as CHREC. */ | |
c2c3fd24 | 309 | |
fb1e4f4a | 310 | struct GTY(()) scev_info_str { |
cbb69ef1 | 311 | unsigned int name_version; |
312 | int instantiated_below; | |
c2c3fd24 | 313 | tree chrec; |
314 | }; | |
315 | ||
316 | /* Counters for the scev database. */ | |
317 | static unsigned nb_set_scev = 0; | |
318 | static unsigned nb_get_scev = 0; | |
319 | ||
320 | /* The following trees are unique elements. Thus the comparison of | |
321 | another element to these elements should be done on the pointer to | |
322 | these trees, and not on their value. */ | |
323 | ||
324 | /* The SSA_NAMEs that are not yet analyzed are qualified with NULL_TREE. */ | |
325 | tree chrec_not_analyzed_yet; | |
326 | ||
327 | /* Reserved to the cases where the analyzer has detected an | |
328 | undecidable property at compile time. */ | |
329 | tree chrec_dont_know; | |
330 | ||
331 | /* When the analyzer has detected that a property will never | |
332 | happen, then it qualifies it with chrec_known. */ | |
333 | tree chrec_known; | |
334 | ||
ccae4f9f | 335 | static GTY ((param_is (struct scev_info_str))) htab_t scalar_evolution_info; |
c2c3fd24 | 336 | |
337 | \f | |
089aa668 | 338 | /* Constructs a new SCEV_INFO_STR structure for VAR and INSTANTIATED_BELOW. */ |
c2c3fd24 | 339 | |
340 | static inline struct scev_info_str * | |
089aa668 | 341 | new_scev_info_str (basic_block instantiated_below, tree var) |
c2c3fd24 | 342 | { |
343 | struct scev_info_str *res; | |
48e1416a | 344 | |
25a27413 | 345 | res = ggc_alloc<scev_info_str> (); |
cbb69ef1 | 346 | res->name_version = SSA_NAME_VERSION (var); |
c2c3fd24 | 347 | res->chrec = chrec_not_analyzed_yet; |
cbb69ef1 | 348 | res->instantiated_below = instantiated_below->index; |
089aa668 | 349 | |
c2c3fd24 | 350 | return res; |
351 | } | |
352 | ||
353 | /* Computes a hash function for database element ELT. */ | |
354 | ||
d9dd21a8 | 355 | static inline hashval_t |
cbb69ef1 | 356 | hash_scev_info (const void *elt_) |
c2c3fd24 | 357 | { |
cbb69ef1 | 358 | const struct scev_info_str *elt = (const struct scev_info_str *) elt_; |
359 | return elt->name_version ^ elt->instantiated_below; | |
c2c3fd24 | 360 | } |
361 | ||
362 | /* Compares database elements E1 and E2. */ | |
363 | ||
d9dd21a8 | 364 | static inline int |
c2c3fd24 | 365 | eq_scev_info (const void *e1, const void *e2) |
366 | { | |
a9c6c0e3 | 367 | const struct scev_info_str *elt1 = (const struct scev_info_str *) e1; |
368 | const struct scev_info_str *elt2 = (const struct scev_info_str *) e2; | |
c2c3fd24 | 369 | |
cbb69ef1 | 370 | return (elt1->name_version == elt2->name_version |
089aa668 | 371 | && elt1->instantiated_below == elt2->instantiated_below); |
c2c3fd24 | 372 | } |
373 | ||
374 | /* Deletes database element E. */ | |
375 | ||
376 | static void | |
377 | del_scev_info (void *e) | |
378 | { | |
ccae4f9f | 379 | ggc_free (e); |
c2c3fd24 | 380 | } |
381 | ||
d9dd21a8 | 382 | |
089aa668 | 383 | /* Get the scalar evolution of VAR for INSTANTIATED_BELOW basic block. |
384 | A first query on VAR returns chrec_not_analyzed_yet. */ | |
c2c3fd24 | 385 | |
386 | static tree * | |
089aa668 | 387 | find_var_scev_info (basic_block instantiated_below, tree var) |
c2c3fd24 | 388 | { |
389 | struct scev_info_str *res; | |
390 | struct scev_info_str tmp; | |
391 | PTR *slot; | |
392 | ||
cbb69ef1 | 393 | tmp.name_version = SSA_NAME_VERSION (var); |
394 | tmp.instantiated_below = instantiated_below->index; | |
c2c3fd24 | 395 | slot = htab_find_slot (scalar_evolution_info, &tmp, INSERT); |
396 | ||
397 | if (!*slot) | |
089aa668 | 398 | *slot = new_scev_info_str (instantiated_below, var); |
a9c6c0e3 | 399 | res = (struct scev_info_str *) *slot; |
c2c3fd24 | 400 | |
401 | return &res->chrec; | |
402 | } | |
403 | ||
c2c3fd24 | 404 | /* Return true when CHREC contains symbolic names defined in |
405 | LOOP_NB. */ | |
406 | ||
48e1416a | 407 | bool |
7ecb5bb2 | 408 | chrec_contains_symbols_defined_in_loop (const_tree chrec, unsigned loop_nb) |
c2c3fd24 | 409 | { |
c2f47e15 | 410 | int i, n; |
411 | ||
c2c3fd24 | 412 | if (chrec == NULL_TREE) |
413 | return false; | |
414 | ||
71d9af81 | 415 | if (is_gimple_min_invariant (chrec)) |
c2c3fd24 | 416 | return false; |
417 | ||
c2c3fd24 | 418 | if (TREE_CODE (chrec) == SSA_NAME) |
419 | { | |
a05095f9 | 420 | gimple def; |
421 | loop_p def_loop, loop; | |
422 | ||
423 | if (SSA_NAME_IS_DEFAULT_DEF (chrec)) | |
424 | return false; | |
425 | ||
426 | def = SSA_NAME_DEF_STMT (chrec); | |
427 | def_loop = loop_containing_stmt (def); | |
41f75a99 | 428 | loop = get_loop (cfun, loop_nb); |
c2c3fd24 | 429 | |
430 | if (def_loop == NULL) | |
431 | return false; | |
432 | ||
433 | if (loop == def_loop || flow_loop_nested_p (loop, def_loop)) | |
434 | return true; | |
435 | ||
436 | return false; | |
437 | } | |
438 | ||
c2f47e15 | 439 | n = TREE_OPERAND_LENGTH (chrec); |
440 | for (i = 0; i < n; i++) | |
48e1416a | 441 | if (chrec_contains_symbols_defined_in_loop (TREE_OPERAND (chrec, i), |
c2f47e15 | 442 | loop_nb)) |
443 | return true; | |
444 | return false; | |
c2c3fd24 | 445 | } |
446 | ||
447 | /* Return true when PHI is a loop-phi-node. */ | |
448 | ||
449 | static bool | |
75a70cf9 | 450 | loop_phi_node_p (gimple phi) |
c2c3fd24 | 451 | { |
452 | /* The implementation of this function is based on the following | |
453 | property: "all the loop-phi-nodes of a loop are contained in the | |
454 | loop's header basic block". */ | |
455 | ||
75a70cf9 | 456 | return loop_containing_stmt (phi)->header == gimple_bb (phi); |
c2c3fd24 | 457 | } |
458 | ||
459 | /* Compute the scalar evolution for EVOLUTION_FN after crossing LOOP. | |
460 | In general, in the case of multivariate evolutions we want to get | |
461 | the evolution in different loops. LOOP specifies the level for | |
462 | which to get the evolution. | |
48e1416a | 463 | |
c2c3fd24 | 464 | Example: |
48e1416a | 465 | |
c2c3fd24 | 466 | | for (j = 0; j < 100; j++) |
467 | | { | |
468 | | for (k = 0; k < 100; k++) | |
469 | | { | |
48e1416a | 470 | | i = k + j; - Here the value of i is a function of j, k. |
c2c3fd24 | 471 | | } |
48e1416a | 472 | | ... = i - Here the value of i is a function of j. |
c2c3fd24 | 473 | | } |
48e1416a | 474 | | ... = i - Here the value of i is a scalar. |
475 | ||
476 | Example: | |
477 | ||
c2c3fd24 | 478 | | i_0 = ... |
479 | | loop_1 10 times | |
480 | | i_1 = phi (i_0, i_2) | |
481 | | i_2 = i_1 + 2 | |
482 | | endloop | |
48e1416a | 483 | |
c2c3fd24 | 484 | This loop has the same effect as: |
485 | LOOP_1 has the same effect as: | |
48e1416a | 486 | |
c2c3fd24 | 487 | | i_1 = i_0 + 20 |
48e1416a | 488 | |
489 | The overall effect of the loop, "i_0 + 20" in the previous example, | |
490 | is obtained by passing in the parameters: LOOP = 1, | |
c2c3fd24 | 491 | EVOLUTION_FN = {i_0, +, 2}_1. |
492 | */ | |
48e1416a | 493 | |
524bc988 | 494 | tree |
c2c3fd24 | 495 | compute_overall_effect_of_inner_loop (struct loop *loop, tree evolution_fn) |
496 | { | |
497 | bool val = false; | |
498 | ||
499 | if (evolution_fn == chrec_dont_know) | |
500 | return chrec_dont_know; | |
501 | ||
502 | else if (TREE_CODE (evolution_fn) == POLYNOMIAL_CHREC) | |
503 | { | |
3bbbcdff | 504 | struct loop *inner_loop = get_chrec_loop (evolution_fn); |
505 | ||
506 | if (inner_loop == loop | |
507 | || flow_loop_nested_p (loop, inner_loop)) | |
c2c3fd24 | 508 | { |
0c3c2e56 | 509 | tree nb_iter = number_of_latch_executions (inner_loop); |
c2c3fd24 | 510 | |
511 | if (nb_iter == chrec_dont_know) | |
512 | return chrec_dont_know; | |
513 | else | |
514 | { | |
515 | tree res; | |
516 | ||
c2c3fd24 | 517 | /* evolution_fn is the evolution function in LOOP. Get |
518 | its value in the nb_iter-th iteration. */ | |
519 | res = chrec_apply (inner_loop->num, evolution_fn, nb_iter); | |
524bc988 | 520 | |
521 | if (chrec_contains_symbols_defined_in_loop (res, loop->num)) | |
522 | res = instantiate_parameters (loop, res); | |
523 | ||
fbf0afd1 | 524 | /* Continue the computation until ending on a parent of LOOP. */ |
c2c3fd24 | 525 | return compute_overall_effect_of_inner_loop (loop, res); |
526 | } | |
527 | } | |
528 | else | |
529 | return evolution_fn; | |
530 | } | |
48e1416a | 531 | |
c2c3fd24 | 532 | /* If the evolution function is an invariant, there is nothing to do. */ |
533 | else if (no_evolution_in_loop_p (evolution_fn, loop->num, &val) && val) | |
534 | return evolution_fn; | |
48e1416a | 535 | |
c2c3fd24 | 536 | else |
537 | return chrec_dont_know; | |
538 | } | |
539 | ||
c2c3fd24 | 540 | /* Associate CHREC to SCALAR. */ |
541 | ||
542 | static void | |
089aa668 | 543 | set_scalar_evolution (basic_block instantiated_below, tree scalar, tree chrec) |
c2c3fd24 | 544 | { |
545 | tree *scalar_info; | |
48e1416a | 546 | |
c2c3fd24 | 547 | if (TREE_CODE (scalar) != SSA_NAME) |
548 | return; | |
549 | ||
089aa668 | 550 | scalar_info = find_var_scev_info (instantiated_below, scalar); |
48e1416a | 551 | |
c2c3fd24 | 552 | if (dump_file) |
553 | { | |
487a9bc1 | 554 | if (dump_flags & TDF_SCEV) |
c2c3fd24 | 555 | { |
556 | fprintf (dump_file, "(set_scalar_evolution \n"); | |
089aa668 | 557 | fprintf (dump_file, " instantiated_below = %d \n", |
558 | instantiated_below->index); | |
c2c3fd24 | 559 | fprintf (dump_file, " (scalar = "); |
560 | print_generic_expr (dump_file, scalar, 0); | |
561 | fprintf (dump_file, ")\n (scalar_evolution = "); | |
562 | print_generic_expr (dump_file, chrec, 0); | |
563 | fprintf (dump_file, "))\n"); | |
564 | } | |
565 | if (dump_flags & TDF_STATS) | |
566 | nb_set_scev++; | |
567 | } | |
48e1416a | 568 | |
c2c3fd24 | 569 | *scalar_info = chrec; |
570 | } | |
571 | ||
089aa668 | 572 | /* Retrieve the chrec associated to SCALAR instantiated below |
573 | INSTANTIATED_BELOW block. */ | |
c2c3fd24 | 574 | |
575 | static tree | |
089aa668 | 576 | get_scalar_evolution (basic_block instantiated_below, tree scalar) |
c2c3fd24 | 577 | { |
578 | tree res; | |
48e1416a | 579 | |
c2c3fd24 | 580 | if (dump_file) |
581 | { | |
487a9bc1 | 582 | if (dump_flags & TDF_SCEV) |
c2c3fd24 | 583 | { |
584 | fprintf (dump_file, "(get_scalar_evolution \n"); | |
585 | fprintf (dump_file, " (scalar = "); | |
586 | print_generic_expr (dump_file, scalar, 0); | |
587 | fprintf (dump_file, ")\n"); | |
588 | } | |
589 | if (dump_flags & TDF_STATS) | |
590 | nb_get_scev++; | |
591 | } | |
48e1416a | 592 | |
c2c3fd24 | 593 | switch (TREE_CODE (scalar)) |
594 | { | |
595 | case SSA_NAME: | |
089aa668 | 596 | res = *find_var_scev_info (instantiated_below, scalar); |
c2c3fd24 | 597 | break; |
598 | ||
599 | case REAL_CST: | |
06f0b99c | 600 | case FIXED_CST: |
c2c3fd24 | 601 | case INTEGER_CST: |
602 | res = scalar; | |
603 | break; | |
604 | ||
605 | default: | |
606 | res = chrec_not_analyzed_yet; | |
607 | break; | |
608 | } | |
48e1416a | 609 | |
487a9bc1 | 610 | if (dump_file && (dump_flags & TDF_SCEV)) |
c2c3fd24 | 611 | { |
612 | fprintf (dump_file, " (scalar_evolution = "); | |
613 | print_generic_expr (dump_file, res, 0); | |
614 | fprintf (dump_file, "))\n"); | |
615 | } | |
48e1416a | 616 | |
c2c3fd24 | 617 | return res; |
618 | } | |
619 | ||
620 | /* Helper function for add_to_evolution. Returns the evolution | |
621 | function for an assignment of the form "a = b + c", where "a" and | |
622 | "b" are on the strongly connected component. CHREC_BEFORE is the | |
623 | information that we already have collected up to this point. | |
48e1416a | 624 | TO_ADD is the evolution of "c". |
625 | ||
c2c3fd24 | 626 | When CHREC_BEFORE has an evolution part in LOOP_NB, add to this |
627 | evolution the expression TO_ADD, otherwise construct an evolution | |
628 | part for this loop. */ | |
629 | ||
630 | static tree | |
f84a688a | 631 | add_to_evolution_1 (unsigned loop_nb, tree chrec_before, tree to_add, |
75a70cf9 | 632 | gimple at_stmt) |
c2c3fd24 | 633 | { |
f84a688a | 634 | tree type, left, right; |
41f75a99 | 635 | struct loop *loop = get_loop (cfun, loop_nb), *chloop; |
f84a688a | 636 | |
c2c3fd24 | 637 | switch (TREE_CODE (chrec_before)) |
638 | { | |
639 | case POLYNOMIAL_CHREC: | |
3bbbcdff | 640 | chloop = get_chrec_loop (chrec_before); |
641 | if (chloop == loop | |
642 | || flow_loop_nested_p (chloop, loop)) | |
c2c3fd24 | 643 | { |
644 | unsigned var; | |
f84a688a | 645 | |
646 | type = chrec_type (chrec_before); | |
48e1416a | 647 | |
c2c3fd24 | 648 | /* When there is no evolution part in this loop, build it. */ |
3bbbcdff | 649 | if (chloop != loop) |
c2c3fd24 | 650 | { |
651 | var = loop_nb; | |
652 | left = chrec_before; | |
eb105b17 | 653 | right = SCALAR_FLOAT_TYPE_P (type) |
654 | ? build_real (type, dconst0) | |
655 | : build_int_cst (type, 0); | |
c2c3fd24 | 656 | } |
657 | else | |
658 | { | |
659 | var = CHREC_VARIABLE (chrec_before); | |
660 | left = CHREC_LEFT (chrec_before); | |
661 | right = CHREC_RIGHT (chrec_before); | |
662 | } | |
663 | ||
f84a688a | 664 | to_add = chrec_convert (type, to_add, at_stmt); |
0de36bdb | 665 | right = chrec_convert_rhs (type, right, at_stmt); |
666 | right = chrec_fold_plus (chrec_type (right), right, to_add); | |
f84a688a | 667 | return build_polynomial_chrec (var, left, right); |
c2c3fd24 | 668 | } |
669 | else | |
f84a688a | 670 | { |
3bbbcdff | 671 | gcc_assert (flow_loop_nested_p (loop, chloop)); |
672 | ||
f84a688a | 673 | /* Search the evolution in LOOP_NB. */ |
674 | left = add_to_evolution_1 (loop_nb, CHREC_LEFT (chrec_before), | |
675 | to_add, at_stmt); | |
676 | right = CHREC_RIGHT (chrec_before); | |
0de36bdb | 677 | right = chrec_convert_rhs (chrec_type (left), right, at_stmt); |
f84a688a | 678 | return build_polynomial_chrec (CHREC_VARIABLE (chrec_before), |
679 | left, right); | |
680 | } | |
48e1416a | 681 | |
c2c3fd24 | 682 | default: |
683 | /* These nodes do not depend on a loop. */ | |
684 | if (chrec_before == chrec_dont_know) | |
685 | return chrec_dont_know; | |
f84a688a | 686 | |
687 | left = chrec_before; | |
0de36bdb | 688 | right = chrec_convert_rhs (chrec_type (left), to_add, at_stmt); |
f84a688a | 689 | return build_polynomial_chrec (loop_nb, left, right); |
c2c3fd24 | 690 | } |
691 | } | |
692 | ||
693 | /* Add TO_ADD to the evolution part of CHREC_BEFORE in the dimension | |
48e1416a | 694 | of LOOP_NB. |
695 | ||
c2c3fd24 | 696 | Description (provided for completeness, for those who read code in |
697 | a plane, and for my poor 62 bytes brain that would have forgotten | |
698 | all this in the next two or three months): | |
48e1416a | 699 | |
c2c3fd24 | 700 | The algorithm of translation of programs from the SSA representation |
701 | into the chrecs syntax is based on a pattern matching. After having | |
702 | reconstructed the overall tree expression for a loop, there are only | |
703 | two cases that can arise: | |
48e1416a | 704 | |
c2c3fd24 | 705 | 1. a = loop-phi (init, a + expr) |
706 | 2. a = loop-phi (init, expr) | |
48e1416a | 707 | |
c2c3fd24 | 708 | where EXPR is either a scalar constant with respect to the analyzed |
709 | loop (this is a degree 0 polynomial), or an expression containing | |
710 | other loop-phi definitions (these are higher degree polynomials). | |
48e1416a | 711 | |
c2c3fd24 | 712 | Examples: |
48e1416a | 713 | |
714 | 1. | |
c2c3fd24 | 715 | | init = ... |
716 | | loop_1 | |
717 | | a = phi (init, a + 5) | |
718 | | endloop | |
48e1416a | 719 | |
720 | 2. | |
c2c3fd24 | 721 | | inita = ... |
722 | | initb = ... | |
723 | | loop_1 | |
724 | | a = phi (inita, 2 * b + 3) | |
725 | | b = phi (initb, b + 1) | |
726 | | endloop | |
48e1416a | 727 | |
728 | For the first case, the semantics of the SSA representation is: | |
729 | ||
c2c3fd24 | 730 | | a (x) = init + \sum_{j = 0}^{x - 1} expr (j) |
48e1416a | 731 | |
c2c3fd24 | 732 | that is, there is a loop index "x" that determines the scalar value |
733 | of the variable during the loop execution. During the first | |
734 | iteration, the value is that of the initial condition INIT, while | |
735 | during the subsequent iterations, it is the sum of the initial | |
736 | condition with the sum of all the values of EXPR from the initial | |
48e1416a | 737 | iteration to the before last considered iteration. |
738 | ||
c2c3fd24 | 739 | For the second case, the semantics of the SSA program is: |
48e1416a | 740 | |
c2c3fd24 | 741 | | a (x) = init, if x = 0; |
742 | | expr (x - 1), otherwise. | |
48e1416a | 743 | |
c2c3fd24 | 744 | The second case corresponds to the PEELED_CHREC, whose syntax is |
48e1416a | 745 | close to the syntax of a loop-phi-node: |
746 | ||
c2c3fd24 | 747 | | phi (init, expr) vs. (init, expr)_x |
48e1416a | 748 | |
c2c3fd24 | 749 | The proof of the translation algorithm for the first case is a |
48e1416a | 750 | proof by structural induction based on the degree of EXPR. |
751 | ||
c2c3fd24 | 752 | Degree 0: |
753 | When EXPR is a constant with respect to the analyzed loop, or in | |
754 | other words when EXPR is a polynomial of degree 0, the evolution of | |
755 | the variable A in the loop is an affine function with an initial | |
756 | condition INIT, and a step EXPR. In order to show this, we start | |
757 | from the semantics of the SSA representation: | |
48e1416a | 758 | |
c2c3fd24 | 759 | f (x) = init + \sum_{j = 0}^{x - 1} expr (j) |
48e1416a | 760 | |
c2c3fd24 | 761 | and since "expr (j)" is a constant with respect to "j", |
48e1416a | 762 | |
763 | f (x) = init + x * expr | |
764 | ||
c2c3fd24 | 765 | Finally, based on the semantics of the pure sum chrecs, by |
766 | identification we get the corresponding chrecs syntax: | |
48e1416a | 767 | |
768 | f (x) = init * \binom{x}{0} + expr * \binom{x}{1} | |
c2c3fd24 | 769 | f (x) -> {init, +, expr}_x |
48e1416a | 770 | |
c2c3fd24 | 771 | Higher degree: |
772 | Suppose that EXPR is a polynomial of degree N with respect to the | |
773 | analyzed loop_x for which we have already determined that it is | |
774 | written under the chrecs syntax: | |
48e1416a | 775 | |
c2c3fd24 | 776 | | expr (x) -> {b_0, +, b_1, +, ..., +, b_{n-1}} (x) |
48e1416a | 777 | |
c2c3fd24 | 778 | We start from the semantics of the SSA program: |
48e1416a | 779 | |
c2c3fd24 | 780 | | f (x) = init + \sum_{j = 0}^{x - 1} expr (j) |
781 | | | |
48e1416a | 782 | | f (x) = init + \sum_{j = 0}^{x - 1} |
c2c3fd24 | 783 | | (b_0 * \binom{j}{0} + ... + b_{n-1} * \binom{j}{n-1}) |
784 | | | |
48e1416a | 785 | | f (x) = init + \sum_{j = 0}^{x - 1} |
786 | | \sum_{k = 0}^{n - 1} (b_k * \binom{j}{k}) | |
c2c3fd24 | 787 | | |
48e1416a | 788 | | f (x) = init + \sum_{k = 0}^{n - 1} |
789 | | (b_k * \sum_{j = 0}^{x - 1} \binom{j}{k}) | |
c2c3fd24 | 790 | | |
48e1416a | 791 | | f (x) = init + \sum_{k = 0}^{n - 1} |
792 | | (b_k * \binom{x}{k + 1}) | |
c2c3fd24 | 793 | | |
48e1416a | 794 | | f (x) = init + b_0 * \binom{x}{1} + ... |
795 | | + b_{n-1} * \binom{x}{n} | |
c2c3fd24 | 796 | | |
48e1416a | 797 | | f (x) = init * \binom{x}{0} + b_0 * \binom{x}{1} + ... |
798 | | + b_{n-1} * \binom{x}{n} | |
c2c3fd24 | 799 | | |
48e1416a | 800 | |
c2c3fd24 | 801 | And finally from the definition of the chrecs syntax, we identify: |
48e1416a | 802 | | f (x) -> {init, +, b_0, +, ..., +, b_{n-1}}_x |
803 | ||
c2c3fd24 | 804 | This shows the mechanism that stands behind the add_to_evolution |
805 | function. An important point is that the use of symbolic | |
806 | parameters avoids the need of an analysis schedule. | |
48e1416a | 807 | |
c2c3fd24 | 808 | Example: |
48e1416a | 809 | |
c2c3fd24 | 810 | | inita = ... |
811 | | initb = ... | |
48e1416a | 812 | | loop_1 |
c2c3fd24 | 813 | | a = phi (inita, a + 2 + b) |
814 | | b = phi (initb, b + 1) | |
815 | | endloop | |
48e1416a | 816 | |
c2c3fd24 | 817 | When analyzing "a", the algorithm keeps "b" symbolically: |
48e1416a | 818 | |
c2c3fd24 | 819 | | a -> {inita, +, 2 + b}_1 |
48e1416a | 820 | |
c2c3fd24 | 821 | Then, after instantiation, the analyzer ends on the evolution: |
48e1416a | 822 | |
c2c3fd24 | 823 | | a -> {inita, +, 2 + initb, +, 1}_1 |
824 | ||
825 | */ | |
826 | ||
48e1416a | 827 | static tree |
f84a688a | 828 | add_to_evolution (unsigned loop_nb, tree chrec_before, enum tree_code code, |
75a70cf9 | 829 | tree to_add, gimple at_stmt) |
c2c3fd24 | 830 | { |
831 | tree type = chrec_type (to_add); | |
832 | tree res = NULL_TREE; | |
48e1416a | 833 | |
c2c3fd24 | 834 | if (to_add == NULL_TREE) |
835 | return chrec_before; | |
48e1416a | 836 | |
c2c3fd24 | 837 | /* TO_ADD is either a scalar, or a parameter. TO_ADD is not |
838 | instantiated at this point. */ | |
839 | if (TREE_CODE (to_add) == POLYNOMIAL_CHREC) | |
840 | /* This should not happen. */ | |
841 | return chrec_dont_know; | |
48e1416a | 842 | |
487a9bc1 | 843 | if (dump_file && (dump_flags & TDF_SCEV)) |
c2c3fd24 | 844 | { |
845 | fprintf (dump_file, "(add_to_evolution \n"); | |
846 | fprintf (dump_file, " (loop_nb = %d)\n", loop_nb); | |
847 | fprintf (dump_file, " (chrec_before = "); | |
848 | print_generic_expr (dump_file, chrec_before, 0); | |
849 | fprintf (dump_file, ")\n (to_add = "); | |
850 | print_generic_expr (dump_file, to_add, 0); | |
851 | fprintf (dump_file, ")\n"); | |
852 | } | |
853 | ||
854 | if (code == MINUS_EXPR) | |
4a1dfa2c | 855 | to_add = chrec_fold_multiply (type, to_add, SCALAR_FLOAT_TYPE_P (type) |
856 | ? build_real (type, dconstm1) | |
857 | : build_int_cst_type (type, -1)); | |
c2c3fd24 | 858 | |
f84a688a | 859 | res = add_to_evolution_1 (loop_nb, chrec_before, to_add, at_stmt); |
c2c3fd24 | 860 | |
487a9bc1 | 861 | if (dump_file && (dump_flags & TDF_SCEV)) |
c2c3fd24 | 862 | { |
863 | fprintf (dump_file, " (res = "); | |
864 | print_generic_expr (dump_file, res, 0); | |
865 | fprintf (dump_file, "))\n"); | |
866 | } | |
867 | ||
868 | return res; | |
869 | } | |
870 | ||
c2c3fd24 | 871 | \f |
872 | ||
873 | /* This section selects the loops that will be good candidates for the | |
874 | scalar evolution analysis. For the moment, greedily select all the | |
875 | loop nests we could analyze. */ | |
876 | ||
c2c3fd24 | 877 | /* For a loop with a single exit edge, return the COND_EXPR that |
878 | guards the exit edge. If the expression is too difficult to | |
879 | analyze, then give up. */ | |
880 | ||
1a91d914 | 881 | gcond * |
1f1872fd | 882 | get_loop_exit_condition (const struct loop *loop) |
c2c3fd24 | 883 | { |
1a91d914 | 884 | gcond *res = NULL; |
d9e7e1a2 | 885 | edge exit_edge = single_exit (loop); |
48e1416a | 886 | |
487a9bc1 | 887 | if (dump_file && (dump_flags & TDF_SCEV)) |
c2c3fd24 | 888 | fprintf (dump_file, "(get_loop_exit_condition \n "); |
48e1416a | 889 | |
bb445479 | 890 | if (exit_edge) |
c2c3fd24 | 891 | { |
75a70cf9 | 892 | gimple stmt; |
48e1416a | 893 | |
75a70cf9 | 894 | stmt = last_stmt (exit_edge->src); |
1a91d914 | 895 | if (gcond *cond_stmt = dyn_cast <gcond *> (stmt)) |
896 | res = cond_stmt; | |
c2c3fd24 | 897 | } |
48e1416a | 898 | |
487a9bc1 | 899 | if (dump_file && (dump_flags & TDF_SCEV)) |
c2c3fd24 | 900 | { |
75a70cf9 | 901 | print_gimple_stmt (dump_file, res, 0, 0); |
c2c3fd24 | 902 | fprintf (dump_file, ")\n"); |
903 | } | |
48e1416a | 904 | |
c2c3fd24 | 905 | return res; |
906 | } | |
907 | ||
c2c3fd24 | 908 | \f |
909 | /* Depth first search algorithm. */ | |
910 | ||
d1de0ec2 | 911 | typedef enum t_bool { |
912 | t_false, | |
913 | t_true, | |
914 | t_dont_know | |
915 | } t_bool; | |
916 | ||
917 | ||
1a91d914 | 918 | static t_bool follow_ssa_edge (struct loop *loop, gimple, gphi *, |
919 | tree *, int); | |
c2c3fd24 | 920 | |
75a70cf9 | 921 | /* Follow the ssa edge into the binary expression RHS0 CODE RHS1. |
c2c3fd24 | 922 | Return true if the strongly connected component has been found. */ |
923 | ||
d1de0ec2 | 924 | static t_bool |
75a70cf9 | 925 | follow_ssa_edge_binary (struct loop *loop, gimple at_stmt, |
926 | tree type, tree rhs0, enum tree_code code, tree rhs1, | |
1a91d914 | 927 | gphi *halting_phi, tree *evolution_of_loop, |
928 | int limit) | |
c2c3fd24 | 929 | { |
d1de0ec2 | 930 | t_bool res = t_false; |
8c9d86fd | 931 | tree evol; |
75a70cf9 | 932 | |
0de36bdb | 933 | switch (code) |
c2c3fd24 | 934 | { |
0de36bdb | 935 | case POINTER_PLUS_EXPR: |
c2c3fd24 | 936 | case PLUS_EXPR: |
c2c3fd24 | 937 | if (TREE_CODE (rhs0) == SSA_NAME) |
938 | { | |
939 | if (TREE_CODE (rhs1) == SSA_NAME) | |
940 | { | |
48e1416a | 941 | /* Match an assignment under the form: |
c2c3fd24 | 942 | "a = b + c". */ |
48e1416a | 943 | |
de39d8ad | 944 | /* We want only assignments of form "name + name" contribute to |
945 | LIMIT, as the other cases do not necessarily contribute to | |
946 | the complexity of the expression. */ | |
947 | limit++; | |
948 | ||
8c9d86fd | 949 | evol = *evolution_of_loop; |
48e1416a | 950 | res = follow_ssa_edge |
75a70cf9 | 951 | (loop, SSA_NAME_DEF_STMT (rhs0), halting_phi, &evol, limit); |
48e1416a | 952 | |
d1de0ec2 | 953 | if (res == t_true) |
48e1416a | 954 | *evolution_of_loop = add_to_evolution |
955 | (loop->num, | |
956 | chrec_convert (type, evol, at_stmt), | |
0de36bdb | 957 | code, rhs1, at_stmt); |
48e1416a | 958 | |
d1de0ec2 | 959 | else if (res == t_false) |
c2c3fd24 | 960 | { |
48e1416a | 961 | res = follow_ssa_edge |
962 | (loop, SSA_NAME_DEF_STMT (rhs1), halting_phi, | |
d1de0ec2 | 963 | evolution_of_loop, limit); |
48e1416a | 964 | |
d1de0ec2 | 965 | if (res == t_true) |
48e1416a | 966 | *evolution_of_loop = add_to_evolution |
967 | (loop->num, | |
968 | chrec_convert (type, *evolution_of_loop, at_stmt), | |
0de36bdb | 969 | code, rhs0, at_stmt); |
d1de0ec2 | 970 | |
971 | else if (res == t_dont_know) | |
972 | *evolution_of_loop = chrec_dont_know; | |
c2c3fd24 | 973 | } |
d1de0ec2 | 974 | |
975 | else if (res == t_dont_know) | |
976 | *evolution_of_loop = chrec_dont_know; | |
c2c3fd24 | 977 | } |
48e1416a | 978 | |
c2c3fd24 | 979 | else |
980 | { | |
48e1416a | 981 | /* Match an assignment under the form: |
c2c3fd24 | 982 | "a = b + ...". */ |
48e1416a | 983 | res = follow_ssa_edge |
984 | (loop, SSA_NAME_DEF_STMT (rhs0), halting_phi, | |
d1de0ec2 | 985 | evolution_of_loop, limit); |
986 | if (res == t_true) | |
48e1416a | 987 | *evolution_of_loop = add_to_evolution |
75a70cf9 | 988 | (loop->num, chrec_convert (type, *evolution_of_loop, |
b3786ab3 | 989 | at_stmt), |
0de36bdb | 990 | code, rhs1, at_stmt); |
d1de0ec2 | 991 | |
992 | else if (res == t_dont_know) | |
993 | *evolution_of_loop = chrec_dont_know; | |
c2c3fd24 | 994 | } |
995 | } | |
48e1416a | 996 | |
c2c3fd24 | 997 | else if (TREE_CODE (rhs1) == SSA_NAME) |
998 | { | |
48e1416a | 999 | /* Match an assignment under the form: |
c2c3fd24 | 1000 | "a = ... + c". */ |
48e1416a | 1001 | res = follow_ssa_edge |
1002 | (loop, SSA_NAME_DEF_STMT (rhs1), halting_phi, | |
d1de0ec2 | 1003 | evolution_of_loop, limit); |
1004 | if (res == t_true) | |
48e1416a | 1005 | *evolution_of_loop = add_to_evolution |
75a70cf9 | 1006 | (loop->num, chrec_convert (type, *evolution_of_loop, |
b3786ab3 | 1007 | at_stmt), |
0de36bdb | 1008 | code, rhs0, at_stmt); |
d1de0ec2 | 1009 | |
1010 | else if (res == t_dont_know) | |
1011 | *evolution_of_loop = chrec_dont_know; | |
c2c3fd24 | 1012 | } |
1013 | ||
1014 | else | |
48e1416a | 1015 | /* Otherwise, match an assignment under the form: |
c2c3fd24 | 1016 | "a = ... + ...". */ |
1017 | /* And there is nothing to do. */ | |
d1de0ec2 | 1018 | res = t_false; |
c2c3fd24 | 1019 | break; |
48e1416a | 1020 | |
c2c3fd24 | 1021 | case MINUS_EXPR: |
1022 | /* This case is under the form "opnd0 = rhs0 - rhs1". */ | |
c2c3fd24 | 1023 | if (TREE_CODE (rhs0) == SSA_NAME) |
c2c3fd24 | 1024 | { |
48e1416a | 1025 | /* Match an assignment under the form: |
11541659 | 1026 | "a = b - ...". */ |
de39d8ad | 1027 | |
1028 | /* We want only assignments of form "name - name" contribute to | |
1029 | LIMIT, as the other cases do not necessarily contribute to | |
1030 | the complexity of the expression. */ | |
1031 | if (TREE_CODE (rhs1) == SSA_NAME) | |
1032 | limit++; | |
1033 | ||
48e1416a | 1034 | res = follow_ssa_edge (loop, SSA_NAME_DEF_STMT (rhs0), halting_phi, |
d1de0ec2 | 1035 | evolution_of_loop, limit); |
1036 | if (res == t_true) | |
48e1416a | 1037 | *evolution_of_loop = add_to_evolution |
75a70cf9 | 1038 | (loop->num, chrec_convert (type, *evolution_of_loop, at_stmt), |
f84a688a | 1039 | MINUS_EXPR, rhs1, at_stmt); |
d1de0ec2 | 1040 | |
1041 | else if (res == t_dont_know) | |
1042 | *evolution_of_loop = chrec_dont_know; | |
c2c3fd24 | 1043 | } |
c2c3fd24 | 1044 | else |
48e1416a | 1045 | /* Otherwise, match an assignment under the form: |
c2c3fd24 | 1046 | "a = ... - ...". */ |
1047 | /* And there is nothing to do. */ | |
d1de0ec2 | 1048 | res = t_false; |
c2c3fd24 | 1049 | break; |
75a70cf9 | 1050 | |
1051 | default: | |
1052 | res = t_false; | |
1053 | } | |
1054 | ||
1055 | return res; | |
1056 | } | |
48e1416a | 1057 | |
75a70cf9 | 1058 | /* Follow the ssa edge into the expression EXPR. |
1059 | Return true if the strongly connected component has been found. */ | |
1060 | ||
1061 | static t_bool | |
48e1416a | 1062 | follow_ssa_edge_expr (struct loop *loop, gimple at_stmt, tree expr, |
1a91d914 | 1063 | gphi *halting_phi, tree *evolution_of_loop, |
1064 | int limit) | |
75a70cf9 | 1065 | { |
191bdb6e | 1066 | enum tree_code code = TREE_CODE (expr); |
1067 | tree type = TREE_TYPE (expr), rhs0, rhs1; | |
1068 | t_bool res; | |
1069 | ||
75a70cf9 | 1070 | /* The EXPR is one of the following cases: |
48e1416a | 1071 | - an SSA_NAME, |
75a70cf9 | 1072 | - an INTEGER_CST, |
48e1416a | 1073 | - a PLUS_EXPR, |
1074 | - a POINTER_PLUS_EXPR, | |
75a70cf9 | 1075 | - a MINUS_EXPR, |
1076 | - an ASSERT_EXPR, | |
1077 | - other cases are not yet handled. */ | |
191bdb6e | 1078 | |
75a70cf9 | 1079 | switch (code) |
1080 | { | |
191bdb6e | 1081 | CASE_CONVERT: |
75a70cf9 | 1082 | /* This assignment is under the form "a_1 = (cast) rhs. */ |
1083 | res = follow_ssa_edge_expr (loop, at_stmt, TREE_OPERAND (expr, 0), | |
1084 | halting_phi, evolution_of_loop, limit); | |
1085 | *evolution_of_loop = chrec_convert (type, *evolution_of_loop, at_stmt); | |
1086 | break; | |
1087 | ||
1088 | case INTEGER_CST: | |
1089 | /* This assignment is under the form "a_1 = 7". */ | |
1090 | res = t_false; | |
1091 | break; | |
191bdb6e | 1092 | |
75a70cf9 | 1093 | case SSA_NAME: |
1094 | /* This assignment is under the form: "a_1 = b_2". */ | |
48e1416a | 1095 | res = follow_ssa_edge |
75a70cf9 | 1096 | (loop, SSA_NAME_DEF_STMT (expr), halting_phi, evolution_of_loop, limit); |
1097 | break; | |
191bdb6e | 1098 | |
75a70cf9 | 1099 | case POINTER_PLUS_EXPR: |
1100 | case PLUS_EXPR: | |
1101 | case MINUS_EXPR: | |
1102 | /* This case is under the form "rhs0 +- rhs1". */ | |
1103 | rhs0 = TREE_OPERAND (expr, 0); | |
1104 | rhs1 = TREE_OPERAND (expr, 1); | |
191bdb6e | 1105 | type = TREE_TYPE (rhs0); |
1106 | STRIP_USELESS_TYPE_CONVERSION (rhs0); | |
1107 | STRIP_USELESS_TYPE_CONVERSION (rhs1); | |
1108 | res = follow_ssa_edge_binary (loop, at_stmt, type, rhs0, code, rhs1, | |
1109 | halting_phi, evolution_of_loop, limit); | |
1110 | break; | |
75a70cf9 | 1111 | |
182cf5a9 | 1112 | case ADDR_EXPR: |
1113 | /* Handle &MEM[ptr + CST] which is equivalent to POINTER_PLUS_EXPR. */ | |
1114 | if (TREE_CODE (TREE_OPERAND (expr, 0)) == MEM_REF) | |
1115 | { | |
1116 | expr = TREE_OPERAND (expr, 0); | |
1117 | rhs0 = TREE_OPERAND (expr, 0); | |
1118 | rhs1 = TREE_OPERAND (expr, 1); | |
1119 | type = TREE_TYPE (rhs0); | |
1120 | STRIP_USELESS_TYPE_CONVERSION (rhs0); | |
1121 | STRIP_USELESS_TYPE_CONVERSION (rhs1); | |
1122 | res = follow_ssa_edge_binary (loop, at_stmt, type, | |
1123 | rhs0, POINTER_PLUS_EXPR, rhs1, | |
1124 | halting_phi, evolution_of_loop, limit); | |
1125 | } | |
1126 | else | |
1127 | res = t_false; | |
1128 | break; | |
1129 | ||
88dbf20f | 1130 | case ASSERT_EXPR: |
191bdb6e | 1131 | /* This assignment is of the form: "a_1 = ASSERT_EXPR <a_2, ...>" |
1132 | It must be handled as a copy assignment of the form a_1 = a_2. */ | |
1133 | rhs0 = ASSERT_EXPR_VAR (expr); | |
1134 | if (TREE_CODE (rhs0) == SSA_NAME) | |
1135 | res = follow_ssa_edge (loop, SSA_NAME_DEF_STMT (rhs0), | |
1136 | halting_phi, evolution_of_loop, limit); | |
1137 | else | |
1138 | res = t_false; | |
1139 | break; | |
88dbf20f | 1140 | |
c2c3fd24 | 1141 | default: |
d1de0ec2 | 1142 | res = t_false; |
c2c3fd24 | 1143 | break; |
1144 | } | |
191bdb6e | 1145 | |
c2c3fd24 | 1146 | return res; |
1147 | } | |
1148 | ||
75a70cf9 | 1149 | /* Follow the ssa edge into the right hand side of an assignment STMT. |
1150 | Return true if the strongly connected component has been found. */ | |
1151 | ||
1152 | static t_bool | |
1153 | follow_ssa_edge_in_rhs (struct loop *loop, gimple stmt, | |
1a91d914 | 1154 | gphi *halting_phi, tree *evolution_of_loop, |
1155 | int limit) | |
75a70cf9 | 1156 | { |
75a70cf9 | 1157 | enum tree_code code = gimple_assign_rhs_code (stmt); |
191bdb6e | 1158 | tree type = gimple_expr_type (stmt), rhs1, rhs2; |
1159 | t_bool res; | |
75a70cf9 | 1160 | |
191bdb6e | 1161 | switch (code) |
75a70cf9 | 1162 | { |
191bdb6e | 1163 | CASE_CONVERT: |
1164 | /* This assignment is under the form "a_1 = (cast) rhs. */ | |
1165 | res = follow_ssa_edge_expr (loop, stmt, gimple_assign_rhs1 (stmt), | |
1166 | halting_phi, evolution_of_loop, limit); | |
1167 | *evolution_of_loop = chrec_convert (type, *evolution_of_loop, stmt); | |
1168 | break; | |
1169 | ||
1170 | case POINTER_PLUS_EXPR: | |
1171 | case PLUS_EXPR: | |
1172 | case MINUS_EXPR: | |
1173 | rhs1 = gimple_assign_rhs1 (stmt); | |
1174 | rhs2 = gimple_assign_rhs2 (stmt); | |
1175 | type = TREE_TYPE (rhs1); | |
1176 | res = follow_ssa_edge_binary (loop, stmt, type, rhs1, code, rhs2, | |
d7e5a0b1 | 1177 | halting_phi, evolution_of_loop, limit); |
191bdb6e | 1178 | break; |
d7e5a0b1 | 1179 | |
75a70cf9 | 1180 | default: |
191bdb6e | 1181 | if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS) |
1182 | res = follow_ssa_edge_expr (loop, stmt, gimple_assign_rhs1 (stmt), | |
1183 | halting_phi, evolution_of_loop, limit); | |
1184 | else | |
1185 | res = t_false; | |
1186 | break; | |
75a70cf9 | 1187 | } |
191bdb6e | 1188 | |
1189 | return res; | |
75a70cf9 | 1190 | } |
1191 | ||
c2c3fd24 | 1192 | /* Checks whether the I-th argument of a PHI comes from a backedge. */ |
1193 | ||
1194 | static bool | |
1a91d914 | 1195 | backedge_phi_arg_p (gphi *phi, int i) |
c2c3fd24 | 1196 | { |
75a70cf9 | 1197 | const_edge e = gimple_phi_arg_edge (phi, i); |
c2c3fd24 | 1198 | |
1199 | /* We would in fact like to test EDGE_DFS_BACK here, but we do not care | |
1200 | about updating it anywhere, and this should work as well most of the | |
1201 | time. */ | |
1202 | if (e->flags & EDGE_IRREDUCIBLE_LOOP) | |
1203 | return true; | |
1204 | ||
1205 | return false; | |
1206 | } | |
1207 | ||
1208 | /* Helper function for one branch of the condition-phi-node. Return | |
1209 | true if the strongly connected component has been found following | |
1210 | this path. */ | |
1211 | ||
d1de0ec2 | 1212 | static inline t_bool |
c2c3fd24 | 1213 | follow_ssa_edge_in_condition_phi_branch (int i, |
48e1416a | 1214 | struct loop *loop, |
1a91d914 | 1215 | gphi *condition_phi, |
1216 | gphi *halting_phi, | |
c2c3fd24 | 1217 | tree *evolution_of_branch, |
d1de0ec2 | 1218 | tree init_cond, int limit) |
c2c3fd24 | 1219 | { |
1220 | tree branch = PHI_ARG_DEF (condition_phi, i); | |
1221 | *evolution_of_branch = chrec_dont_know; | |
1222 | ||
1223 | /* Do not follow back edges (they must belong to an irreducible loop, which | |
1224 | we really do not want to worry about). */ | |
1225 | if (backedge_phi_arg_p (condition_phi, i)) | |
d1de0ec2 | 1226 | return t_false; |
c2c3fd24 | 1227 | |
1228 | if (TREE_CODE (branch) == SSA_NAME) | |
1229 | { | |
1230 | *evolution_of_branch = init_cond; | |
48e1416a | 1231 | return follow_ssa_edge (loop, SSA_NAME_DEF_STMT (branch), halting_phi, |
d1de0ec2 | 1232 | evolution_of_branch, limit); |
c2c3fd24 | 1233 | } |
1234 | ||
48e1416a | 1235 | /* This case occurs when one of the condition branches sets |
5c9dae64 | 1236 | the variable to a constant: i.e. a phi-node like |
48e1416a | 1237 | "a_2 = PHI <a_7(5), 2(6)>;". |
1238 | ||
1239 | FIXME: This case have to be refined correctly: | |
c2c3fd24 | 1240 | in some cases it is possible to say something better than |
1241 | chrec_dont_know, for example using a wrap-around notation. */ | |
d1de0ec2 | 1242 | return t_false; |
c2c3fd24 | 1243 | } |
1244 | ||
1245 | /* This function merges the branches of a condition-phi-node in a | |
1246 | loop. */ | |
1247 | ||
d1de0ec2 | 1248 | static t_bool |
c2c3fd24 | 1249 | follow_ssa_edge_in_condition_phi (struct loop *loop, |
1a91d914 | 1250 | gphi *condition_phi, |
1251 | gphi *halting_phi, | |
d1de0ec2 | 1252 | tree *evolution_of_loop, int limit) |
c2c3fd24 | 1253 | { |
75a70cf9 | 1254 | int i, n; |
c2c3fd24 | 1255 | tree init = *evolution_of_loop; |
1256 | tree evolution_of_branch; | |
d1de0ec2 | 1257 | t_bool res = follow_ssa_edge_in_condition_phi_branch (0, loop, condition_phi, |
1258 | halting_phi, | |
1259 | &evolution_of_branch, | |
1260 | init, limit); | |
1261 | if (res == t_false || res == t_dont_know) | |
1262 | return res; | |
c2c3fd24 | 1263 | |
c2c3fd24 | 1264 | *evolution_of_loop = evolution_of_branch; |
1265 | ||
75a70cf9 | 1266 | n = gimple_phi_num_args (condition_phi); |
75a70cf9 | 1267 | for (i = 1; i < n; i++) |
c2c3fd24 | 1268 | { |
c4485791 | 1269 | /* Quickly give up when the evolution of one of the branches is |
1270 | not known. */ | |
1271 | if (*evolution_of_loop == chrec_dont_know) | |
d1de0ec2 | 1272 | return t_true; |
c4485791 | 1273 | |
aebe538b | 1274 | /* Increase the limit by the PHI argument number to avoid exponential |
1275 | time and memory complexity. */ | |
d1de0ec2 | 1276 | res = follow_ssa_edge_in_condition_phi_branch (i, loop, condition_phi, |
1277 | halting_phi, | |
1278 | &evolution_of_branch, | |
aebe538b | 1279 | init, limit + i); |
d1de0ec2 | 1280 | if (res == t_false || res == t_dont_know) |
1281 | return res; | |
c2c3fd24 | 1282 | |
1283 | *evolution_of_loop = chrec_merge (*evolution_of_loop, | |
1284 | evolution_of_branch); | |
1285 | } | |
48e1416a | 1286 | |
d1de0ec2 | 1287 | return t_true; |
c2c3fd24 | 1288 | } |
1289 | ||
1290 | /* Follow an SSA edge in an inner loop. It computes the overall | |
1291 | effect of the loop, and following the symbolic initial conditions, | |
1292 | it follows the edges in the parent loop. The inner loop is | |
1293 | considered as a single statement. */ | |
1294 | ||
d1de0ec2 | 1295 | static t_bool |
c2c3fd24 | 1296 | follow_ssa_edge_inner_loop_phi (struct loop *outer_loop, |
1a91d914 | 1297 | gphi *loop_phi_node, |
1298 | gphi *halting_phi, | |
d1de0ec2 | 1299 | tree *evolution_of_loop, int limit) |
c2c3fd24 | 1300 | { |
1301 | struct loop *loop = loop_containing_stmt (loop_phi_node); | |
1302 | tree ev = analyze_scalar_evolution (loop, PHI_RESULT (loop_phi_node)); | |
1303 | ||
1304 | /* Sometimes, the inner loop is too difficult to analyze, and the | |
1305 | result of the analysis is a symbolic parameter. */ | |
1306 | if (ev == PHI_RESULT (loop_phi_node)) | |
1307 | { | |
d1de0ec2 | 1308 | t_bool res = t_false; |
75a70cf9 | 1309 | int i, n = gimple_phi_num_args (loop_phi_node); |
c2c3fd24 | 1310 | |
75a70cf9 | 1311 | for (i = 0; i < n; i++) |
c2c3fd24 | 1312 | { |
1313 | tree arg = PHI_ARG_DEF (loop_phi_node, i); | |
1314 | basic_block bb; | |
1315 | ||
1316 | /* Follow the edges that exit the inner loop. */ | |
75a70cf9 | 1317 | bb = gimple_phi_arg_edge (loop_phi_node, i)->src; |
c2c3fd24 | 1318 | if (!flow_bb_inside_loop_p (loop, bb)) |
75a70cf9 | 1319 | res = follow_ssa_edge_expr (outer_loop, loop_phi_node, |
1320 | arg, halting_phi, | |
1321 | evolution_of_loop, limit); | |
d1de0ec2 | 1322 | if (res == t_true) |
1323 | break; | |
c2c3fd24 | 1324 | } |
1325 | ||
1326 | /* If the path crosses this loop-phi, give up. */ | |
d1de0ec2 | 1327 | if (res == t_true) |
c2c3fd24 | 1328 | *evolution_of_loop = chrec_dont_know; |
1329 | ||
1330 | return res; | |
1331 | } | |
1332 | ||
1333 | /* Otherwise, compute the overall effect of the inner loop. */ | |
1334 | ev = compute_overall_effect_of_inner_loop (loop, ev); | |
75a70cf9 | 1335 | return follow_ssa_edge_expr (outer_loop, loop_phi_node, ev, halting_phi, |
1336 | evolution_of_loop, limit); | |
c2c3fd24 | 1337 | } |
1338 | ||
1339 | /* Follow an SSA edge from a loop-phi-node to itself, constructing a | |
1340 | path that is analyzed on the return walk. */ | |
1341 | ||
d1de0ec2 | 1342 | static t_bool |
1a91d914 | 1343 | follow_ssa_edge (struct loop *loop, gimple def, gphi *halting_phi, |
d1de0ec2 | 1344 | tree *evolution_of_loop, int limit) |
c2c3fd24 | 1345 | { |
1346 | struct loop *def_loop; | |
48e1416a | 1347 | |
75a70cf9 | 1348 | if (gimple_nop_p (def)) |
d1de0ec2 | 1349 | return t_false; |
48e1416a | 1350 | |
d1de0ec2 | 1351 | /* Give up if the path is longer than the MAX that we allow. */ |
99df7432 | 1352 | if (limit > PARAM_VALUE (PARAM_SCEV_MAX_EXPR_COMPLEXITY)) |
d1de0ec2 | 1353 | return t_dont_know; |
48e1416a | 1354 | |
c2c3fd24 | 1355 | def_loop = loop_containing_stmt (def); |
48e1416a | 1356 | |
75a70cf9 | 1357 | switch (gimple_code (def)) |
c2c3fd24 | 1358 | { |
75a70cf9 | 1359 | case GIMPLE_PHI: |
c2c3fd24 | 1360 | if (!loop_phi_node_p (def)) |
1361 | /* DEF is a condition-phi-node. Follow the branches, and | |
1362 | record their evolutions. Finally, merge the collected | |
1363 | information and set the approximation to the main | |
1364 | variable. */ | |
48e1416a | 1365 | return follow_ssa_edge_in_condition_phi |
1a91d914 | 1366 | (loop, as_a <gphi *> (def), halting_phi, evolution_of_loop, |
1367 | limit); | |
c2c3fd24 | 1368 | |
1369 | /* When the analyzed phi is the halting_phi, the | |
1370 | depth-first search is over: we have found a path from | |
1371 | the halting_phi to itself in the loop. */ | |
1372 | if (def == halting_phi) | |
d1de0ec2 | 1373 | return t_true; |
48e1416a | 1374 | |
c2c3fd24 | 1375 | /* Otherwise, the evolution of the HALTING_PHI depends |
5c9dae64 | 1376 | on the evolution of another loop-phi-node, i.e. the |
c2c3fd24 | 1377 | evolution function is a higher degree polynomial. */ |
1378 | if (def_loop == loop) | |
d1de0ec2 | 1379 | return t_false; |
48e1416a | 1380 | |
c2c3fd24 | 1381 | /* Inner loop. */ |
1382 | if (flow_loop_nested_p (loop, def_loop)) | |
48e1416a | 1383 | return follow_ssa_edge_inner_loop_phi |
1a91d914 | 1384 | (loop, as_a <gphi *> (def), halting_phi, evolution_of_loop, |
1385 | limit + 1); | |
c2c3fd24 | 1386 | |
1387 | /* Outer loop. */ | |
d1de0ec2 | 1388 | return t_false; |
c2c3fd24 | 1389 | |
75a70cf9 | 1390 | case GIMPLE_ASSIGN: |
48e1416a | 1391 | return follow_ssa_edge_in_rhs (loop, def, halting_phi, |
d1de0ec2 | 1392 | evolution_of_loop, limit); |
48e1416a | 1393 | |
c2c3fd24 | 1394 | default: |
1395 | /* At this level of abstraction, the program is just a set | |
75a70cf9 | 1396 | of GIMPLE_ASSIGNs and PHI_NODEs. In principle there is no |
c2c3fd24 | 1397 | other node to be handled. */ |
d1de0ec2 | 1398 | return t_false; |
c2c3fd24 | 1399 | } |
1400 | } | |
1401 | ||
1402 | \f | |
c03531c4 | 1403 | /* Simplify PEELED_CHREC represented by (init_cond, arg) in LOOP. |
1404 | Handle below case and return the corresponding POLYNOMIAL_CHREC: | |
1405 | ||
1406 | # i_17 = PHI <i_13(5), 0(3)> | |
1407 | # _20 = PHI <_5(5), start_4(D)(3)> | |
1408 | ... | |
1409 | i_13 = i_17 + 1; | |
1410 | _5 = start_4(D) + i_13; | |
1411 | ||
1412 | Though variable _20 appears as a PEELED_CHREC in the form of | |
1413 | (start_4, _5)_LOOP, it's a POLYNOMIAL_CHREC like {start_4, 1}_LOOP. | |
1414 | ||
1415 | See PR41488. */ | |
1416 | ||
1417 | static tree | |
1418 | simplify_peeled_chrec (struct loop *loop, tree arg, tree init_cond) | |
1419 | { | |
1420 | aff_tree aff1, aff2; | |
1421 | tree ev, left, right, type, step_val; | |
5f8841a5 | 1422 | hash_map<tree, name_expansion *> *peeled_chrec_map = NULL; |
c03531c4 | 1423 | |
1424 | ev = instantiate_parameters (loop, analyze_scalar_evolution (loop, arg)); | |
1425 | if (ev == NULL_TREE || TREE_CODE (ev) != POLYNOMIAL_CHREC) | |
1426 | return chrec_dont_know; | |
1427 | ||
1428 | left = CHREC_LEFT (ev); | |
1429 | right = CHREC_RIGHT (ev); | |
1430 | type = TREE_TYPE (left); | |
1431 | step_val = chrec_fold_plus (type, init_cond, right); | |
1432 | ||
1433 | /* Transform (init, {left, right}_LOOP)_LOOP to {init, right}_LOOP | |
1434 | if "left" equals to "init + right". */ | |
1435 | if (operand_equal_p (left, step_val, 0)) | |
1436 | { | |
1437 | if (dump_file && (dump_flags & TDF_SCEV)) | |
1438 | fprintf (dump_file, "Simplify PEELED_CHREC into POLYNOMIAL_CHREC.\n"); | |
1439 | ||
1440 | return build_polynomial_chrec (loop->num, init_cond, right); | |
1441 | } | |
1442 | ||
1443 | /* Try harder to check if they are equal. */ | |
1444 | tree_to_aff_combination_expand (left, type, &aff1, &peeled_chrec_map); | |
1445 | tree_to_aff_combination_expand (step_val, type, &aff2, &peeled_chrec_map); | |
1446 | free_affine_expand_cache (&peeled_chrec_map); | |
a2d59721 | 1447 | aff_combination_scale (&aff2, -1); |
c03531c4 | 1448 | aff_combination_add (&aff1, &aff2); |
1449 | ||
1450 | /* Transform (init, {left, right}_LOOP)_LOOP to {init, right}_LOOP | |
1451 | if "left" equals to "init + right". */ | |
1452 | if (aff_combination_zero_p (&aff1)) | |
1453 | { | |
1454 | if (dump_file && (dump_flags & TDF_SCEV)) | |
1455 | fprintf (dump_file, "Simplify PEELED_CHREC into POLYNOMIAL_CHREC.\n"); | |
1456 | ||
1457 | return build_polynomial_chrec (loop->num, init_cond, right); | |
1458 | } | |
1459 | return chrec_dont_know; | |
1460 | } | |
c2c3fd24 | 1461 | |
1462 | /* Given a LOOP_PHI_NODE, this function determines the evolution | |
1463 | function from LOOP_PHI_NODE to LOOP_PHI_NODE in the loop. */ | |
1464 | ||
1465 | static tree | |
1a91d914 | 1466 | analyze_evolution_in_loop (gphi *loop_phi_node, |
c2c3fd24 | 1467 | tree init_cond) |
1468 | { | |
75a70cf9 | 1469 | int i, n = gimple_phi_num_args (loop_phi_node); |
c2c3fd24 | 1470 | tree evolution_function = chrec_not_analyzed_yet; |
1471 | struct loop *loop = loop_containing_stmt (loop_phi_node); | |
1472 | basic_block bb; | |
c03531c4 | 1473 | static bool simplify_peeled_chrec_p = true; |
48e1416a | 1474 | |
487a9bc1 | 1475 | if (dump_file && (dump_flags & TDF_SCEV)) |
c2c3fd24 | 1476 | { |
1477 | fprintf (dump_file, "(analyze_evolution_in_loop \n"); | |
1478 | fprintf (dump_file, " (loop_phi_node = "); | |
75a70cf9 | 1479 | print_gimple_stmt (dump_file, loop_phi_node, 0, 0); |
c2c3fd24 | 1480 | fprintf (dump_file, ")\n"); |
1481 | } | |
48e1416a | 1482 | |
75a70cf9 | 1483 | for (i = 0; i < n; i++) |
c2c3fd24 | 1484 | { |
1485 | tree arg = PHI_ARG_DEF (loop_phi_node, i); | |
75a70cf9 | 1486 | gimple ssa_chain; |
1487 | tree ev_fn; | |
1aa768f0 | 1488 | t_bool res; |
c2c3fd24 | 1489 | |
1490 | /* Select the edges that enter the loop body. */ | |
75a70cf9 | 1491 | bb = gimple_phi_arg_edge (loop_phi_node, i)->src; |
c2c3fd24 | 1492 | if (!flow_bb_inside_loop_p (loop, bb)) |
1493 | continue; | |
8da11536 | 1494 | |
c2c3fd24 | 1495 | if (TREE_CODE (arg) == SSA_NAME) |
1496 | { | |
8da11536 | 1497 | bool val = false; |
1498 | ||
c2c3fd24 | 1499 | ssa_chain = SSA_NAME_DEF_STMT (arg); |
1500 | ||
1501 | /* Pass in the initial condition to the follow edge function. */ | |
1502 | ev_fn = init_cond; | |
d1de0ec2 | 1503 | res = follow_ssa_edge (loop, ssa_chain, loop_phi_node, &ev_fn, 0); |
8da11536 | 1504 | |
1505 | /* If ev_fn has no evolution in the inner loop, and the | |
1506 | init_cond is not equal to ev_fn, then we have an | |
1507 | ambiguity between two possible values, as we cannot know | |
1508 | the number of iterations at this point. */ | |
1509 | if (TREE_CODE (ev_fn) != POLYNOMIAL_CHREC | |
1510 | && no_evolution_in_loop_p (ev_fn, loop->num, &val) && val | |
1511 | && !operand_equal_p (init_cond, ev_fn, 0)) | |
1512 | ev_fn = chrec_dont_know; | |
c2c3fd24 | 1513 | } |
1514 | else | |
1aa768f0 | 1515 | res = t_false; |
8da11536 | 1516 | |
c2c3fd24 | 1517 | /* When it is impossible to go back on the same |
1518 | loop_phi_node by following the ssa edges, the | |
5c9dae64 | 1519 | evolution is represented by a peeled chrec, i.e. the |
c2c3fd24 | 1520 | first iteration, EV_FN has the value INIT_COND, then |
48e1416a | 1521 | all the other iterations it has the value of ARG. |
c2c3fd24 | 1522 | For the moment, PEELED_CHREC nodes are not built. */ |
1aa768f0 | 1523 | if (res != t_true) |
c03531c4 | 1524 | { |
1525 | ev_fn = chrec_dont_know; | |
1526 | /* Try to recognize POLYNOMIAL_CHREC which appears in | |
1527 | the form of PEELED_CHREC, but guard the process with | |
1528 | a bool variable to keep the analyzer from infinite | |
1529 | recurrence for real PEELED_RECs. */ | |
1530 | if (simplify_peeled_chrec_p && TREE_CODE (arg) == SSA_NAME) | |
1531 | { | |
1532 | simplify_peeled_chrec_p = false; | |
1533 | ev_fn = simplify_peeled_chrec (loop, arg, init_cond); | |
1534 | simplify_peeled_chrec_p = true; | |
1535 | } | |
1536 | } | |
48e1416a | 1537 | |
c2c3fd24 | 1538 | /* When there are multiple back edges of the loop (which in fact never |
fbf0afd1 | 1539 | happens currently, but nevertheless), merge their evolutions. */ |
c2c3fd24 | 1540 | evolution_function = chrec_merge (evolution_function, ev_fn); |
1541 | } | |
48e1416a | 1542 | |
487a9bc1 | 1543 | if (dump_file && (dump_flags & TDF_SCEV)) |
c2c3fd24 | 1544 | { |
1545 | fprintf (dump_file, " (evolution_function = "); | |
1546 | print_generic_expr (dump_file, evolution_function, 0); | |
1547 | fprintf (dump_file, "))\n"); | |
1548 | } | |
48e1416a | 1549 | |
c2c3fd24 | 1550 | return evolution_function; |
1551 | } | |
1552 | ||
1553 | /* Given a loop-phi-node, return the initial conditions of the | |
1554 | variable on entry of the loop. When the CCP has propagated | |
1555 | constants into the loop-phi-node, the initial condition is | |
1556 | instantiated, otherwise the initial condition is kept symbolic. | |
1557 | This analyzer does not analyze the evolution outside the current | |
1558 | loop, and leaves this task to the on-demand tree reconstructor. */ | |
1559 | ||
48e1416a | 1560 | static tree |
1a91d914 | 1561 | analyze_initial_condition (gphi *loop_phi_node) |
c2c3fd24 | 1562 | { |
75a70cf9 | 1563 | int i, n; |
c2c3fd24 | 1564 | tree init_cond = chrec_not_analyzed_yet; |
75a70cf9 | 1565 | struct loop *loop = loop_containing_stmt (loop_phi_node); |
48e1416a | 1566 | |
487a9bc1 | 1567 | if (dump_file && (dump_flags & TDF_SCEV)) |
c2c3fd24 | 1568 | { |
1569 | fprintf (dump_file, "(analyze_initial_condition \n"); | |
1570 | fprintf (dump_file, " (loop_phi_node = \n"); | |
75a70cf9 | 1571 | print_gimple_stmt (dump_file, loop_phi_node, 0, 0); |
c2c3fd24 | 1572 | fprintf (dump_file, ")\n"); |
1573 | } | |
48e1416a | 1574 | |
75a70cf9 | 1575 | n = gimple_phi_num_args (loop_phi_node); |
1576 | for (i = 0; i < n; i++) | |
c2c3fd24 | 1577 | { |
1578 | tree branch = PHI_ARG_DEF (loop_phi_node, i); | |
75a70cf9 | 1579 | basic_block bb = gimple_phi_arg_edge (loop_phi_node, i)->src; |
48e1416a | 1580 | |
c2c3fd24 | 1581 | /* When the branch is oriented to the loop's body, it does |
1582 | not contribute to the initial condition. */ | |
1583 | if (flow_bb_inside_loop_p (loop, bb)) | |
1584 | continue; | |
1585 | ||
1586 | if (init_cond == chrec_not_analyzed_yet) | |
1587 | { | |
1588 | init_cond = branch; | |
1589 | continue; | |
1590 | } | |
1591 | ||
1592 | if (TREE_CODE (branch) == SSA_NAME) | |
1593 | { | |
1594 | init_cond = chrec_dont_know; | |
1595 | break; | |
1596 | } | |
1597 | ||
1598 | init_cond = chrec_merge (init_cond, branch); | |
1599 | } | |
1600 | ||
1601 | /* Ooops -- a loop without an entry??? */ | |
1602 | if (init_cond == chrec_not_analyzed_yet) | |
1603 | init_cond = chrec_dont_know; | |
1604 | ||
ac9b13de | 1605 | /* During early loop unrolling we do not have fully constant propagated IL. |
1606 | Handle degenerate PHIs here to not miss important unrollings. */ | |
1607 | if (TREE_CODE (init_cond) == SSA_NAME) | |
1608 | { | |
1609 | gimple def = SSA_NAME_DEF_STMT (init_cond); | |
1a91d914 | 1610 | if (gphi *phi = dyn_cast <gphi *> (def)) |
1611 | { | |
1612 | tree res = degenerate_phi_result (phi); | |
1613 | if (res != NULL_TREE | |
1614 | /* Only allow invariants here, otherwise we may break | |
1615 | loop-closed SSA form. */ | |
1616 | && is_gimple_min_invariant (res)) | |
1617 | init_cond = res; | |
1618 | } | |
ac9b13de | 1619 | } |
1620 | ||
487a9bc1 | 1621 | if (dump_file && (dump_flags & TDF_SCEV)) |
c2c3fd24 | 1622 | { |
1623 | fprintf (dump_file, " (init_cond = "); | |
1624 | print_generic_expr (dump_file, init_cond, 0); | |
1625 | fprintf (dump_file, "))\n"); | |
1626 | } | |
48e1416a | 1627 | |
c2c3fd24 | 1628 | return init_cond; |
1629 | } | |
1630 | ||
1631 | /* Analyze the scalar evolution for LOOP_PHI_NODE. */ | |
1632 | ||
48e1416a | 1633 | static tree |
1a91d914 | 1634 | interpret_loop_phi (struct loop *loop, gphi *loop_phi_node) |
c2c3fd24 | 1635 | { |
1636 | tree res; | |
1637 | struct loop *phi_loop = loop_containing_stmt (loop_phi_node); | |
1638 | tree init_cond; | |
48e1416a | 1639 | |
c2c3fd24 | 1640 | if (phi_loop != loop) |
1641 | { | |
1642 | struct loop *subloop; | |
1643 | tree evolution_fn = analyze_scalar_evolution | |
1644 | (phi_loop, PHI_RESULT (loop_phi_node)); | |
1645 | ||
1646 | /* Dive one level deeper. */ | |
9e3536f4 | 1647 | subloop = superloop_at_depth (phi_loop, loop_depth (loop) + 1); |
c2c3fd24 | 1648 | |
1649 | /* Interpret the subloop. */ | |
1650 | res = compute_overall_effect_of_inner_loop (subloop, evolution_fn); | |
1651 | return res; | |
1652 | } | |
1653 | ||
1654 | /* Otherwise really interpret the loop phi. */ | |
1655 | init_cond = analyze_initial_condition (loop_phi_node); | |
1656 | res = analyze_evolution_in_loop (loop_phi_node, init_cond); | |
1657 | ||
ce00c150 | 1658 | /* Verify we maintained the correct initial condition throughout |
1659 | possible conversions in the SSA chain. */ | |
1660 | if (res != chrec_dont_know) | |
1661 | { | |
1662 | tree new_init = res; | |
1663 | if (CONVERT_EXPR_P (res) | |
1664 | && TREE_CODE (TREE_OPERAND (res, 0)) == POLYNOMIAL_CHREC) | |
1665 | new_init = fold_convert (TREE_TYPE (res), | |
1666 | CHREC_LEFT (TREE_OPERAND (res, 0))); | |
1667 | else if (TREE_CODE (res) == POLYNOMIAL_CHREC) | |
1668 | new_init = CHREC_LEFT (res); | |
1669 | STRIP_USELESS_TYPE_CONVERSION (new_init); | |
7624240a | 1670 | if (TREE_CODE (new_init) == POLYNOMIAL_CHREC |
1671 | || !operand_equal_p (init_cond, new_init, 0)) | |
ce00c150 | 1672 | return chrec_dont_know; |
1673 | } | |
1674 | ||
c2c3fd24 | 1675 | return res; |
1676 | } | |
1677 | ||
1678 | /* This function merges the branches of a condition-phi-node, | |
1679 | contained in the outermost loop, and whose arguments are already | |
1680 | analyzed. */ | |
1681 | ||
1682 | static tree | |
1a91d914 | 1683 | interpret_condition_phi (struct loop *loop, gphi *condition_phi) |
c2c3fd24 | 1684 | { |
75a70cf9 | 1685 | int i, n = gimple_phi_num_args (condition_phi); |
c2c3fd24 | 1686 | tree res = chrec_not_analyzed_yet; |
48e1416a | 1687 | |
75a70cf9 | 1688 | for (i = 0; i < n; i++) |
c2c3fd24 | 1689 | { |
1690 | tree branch_chrec; | |
48e1416a | 1691 | |
c2c3fd24 | 1692 | if (backedge_phi_arg_p (condition_phi, i)) |
1693 | { | |
1694 | res = chrec_dont_know; | |
1695 | break; | |
1696 | } | |
1697 | ||
1698 | branch_chrec = analyze_scalar_evolution | |
1699 | (loop, PHI_ARG_DEF (condition_phi, i)); | |
48e1416a | 1700 | |
c2c3fd24 | 1701 | res = chrec_merge (res, branch_chrec); |
1702 | } | |
1703 | ||
1704 | return res; | |
1705 | } | |
1706 | ||
75a70cf9 | 1707 | /* Interpret the operation RHS1 OP RHS2. If we didn't |
0b94b8c8 | 1708 | analyze this node before, follow the definitions until ending |
75a70cf9 | 1709 | either on an analyzed GIMPLE_ASSIGN, or on a loop-phi-node. On the |
c2c3fd24 | 1710 | return path, this function propagates evolutions (ala constant copy |
1711 | propagation). OPND1 is not a GIMPLE expression because we could | |
1712 | analyze the effect of an inner loop: see interpret_loop_phi. */ | |
1713 | ||
1714 | static tree | |
75a70cf9 | 1715 | interpret_rhs_expr (struct loop *loop, gimple at_stmt, |
1716 | tree type, tree rhs1, enum tree_code code, tree rhs2) | |
c2c3fd24 | 1717 | { |
75a70cf9 | 1718 | tree res, chrec1, chrec2; |
3ef23449 | 1719 | gimple def; |
75a70cf9 | 1720 | |
1721 | if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS) | |
1722 | { | |
1723 | if (is_gimple_min_invariant (rhs1)) | |
1724 | return chrec_convert (type, rhs1, at_stmt); | |
1725 | ||
1726 | if (code == SSA_NAME) | |
1727 | return chrec_convert (type, analyze_scalar_evolution (loop, rhs1), | |
1728 | at_stmt); | |
b3786ab3 | 1729 | |
75a70cf9 | 1730 | if (code == ASSERT_EXPR) |
1731 | { | |
1732 | rhs1 = ASSERT_EXPR_VAR (rhs1); | |
1733 | return chrec_convert (type, analyze_scalar_evolution (loop, rhs1), | |
1734 | at_stmt); | |
1735 | } | |
75a70cf9 | 1736 | } |
b3786ab3 | 1737 | |
75a70cf9 | 1738 | switch (code) |
c2c3fd24 | 1739 | { |
1214c397 | 1740 | case ADDR_EXPR: |
62bc06ea | 1741 | if (TREE_CODE (TREE_OPERAND (rhs1, 0)) == MEM_REF |
1742 | || handled_component_p (TREE_OPERAND (rhs1, 0))) | |
1743 | { | |
3754d046 | 1744 | machine_mode mode; |
62bc06ea | 1745 | HOST_WIDE_INT bitsize, bitpos; |
1746 | int unsignedp; | |
1747 | int volatilep = 0; | |
1748 | tree base, offset; | |
1749 | tree chrec3; | |
1750 | tree unitpos; | |
1751 | ||
1752 | base = get_inner_reference (TREE_OPERAND (rhs1, 0), | |
1753 | &bitsize, &bitpos, &offset, | |
dc317fc8 | 1754 | &mode, &unsignedp, &volatilep, false); |
62bc06ea | 1755 | |
1756 | if (TREE_CODE (base) == MEM_REF) | |
1757 | { | |
1758 | rhs2 = TREE_OPERAND (base, 1); | |
1759 | rhs1 = TREE_OPERAND (base, 0); | |
1760 | ||
1761 | chrec1 = analyze_scalar_evolution (loop, rhs1); | |
1762 | chrec2 = analyze_scalar_evolution (loop, rhs2); | |
1763 | chrec1 = chrec_convert (type, chrec1, at_stmt); | |
1764 | chrec2 = chrec_convert (TREE_TYPE (rhs2), chrec2, at_stmt); | |
32e31826 | 1765 | chrec1 = instantiate_parameters (loop, chrec1); |
1766 | chrec2 = instantiate_parameters (loop, chrec2); | |
62bc06ea | 1767 | res = chrec_fold_plus (type, chrec1, chrec2); |
1768 | } | |
1769 | else | |
1770 | { | |
1771 | chrec1 = analyze_scalar_evolution_for_address_of (loop, base); | |
1772 | chrec1 = chrec_convert (type, chrec1, at_stmt); | |
1773 | res = chrec1; | |
1774 | } | |
1214c397 | 1775 | |
62bc06ea | 1776 | if (offset != NULL_TREE) |
1777 | { | |
1778 | chrec2 = analyze_scalar_evolution (loop, offset); | |
1779 | chrec2 = chrec_convert (TREE_TYPE (offset), chrec2, at_stmt); | |
32e31826 | 1780 | chrec2 = instantiate_parameters (loop, chrec2); |
62bc06ea | 1781 | res = chrec_fold_plus (type, res, chrec2); |
1782 | } | |
1783 | ||
1784 | if (bitpos != 0) | |
1785 | { | |
1786 | gcc_assert ((bitpos % BITS_PER_UNIT) == 0); | |
1787 | ||
748e5d45 | 1788 | unitpos = size_int (bitpos / BITS_PER_UNIT); |
62bc06ea | 1789 | chrec3 = analyze_scalar_evolution (loop, unitpos); |
1790 | chrec3 = chrec_convert (TREE_TYPE (unitpos), chrec3, at_stmt); | |
32e31826 | 1791 | chrec3 = instantiate_parameters (loop, chrec3); |
62bc06ea | 1792 | res = chrec_fold_plus (type, res, chrec3); |
1793 | } | |
1794 | } | |
1795 | else | |
1796 | res = chrec_dont_know; | |
1797 | break; | |
1214c397 | 1798 | |
0de36bdb | 1799 | case POINTER_PLUS_EXPR: |
75a70cf9 | 1800 | chrec1 = analyze_scalar_evolution (loop, rhs1); |
1801 | chrec2 = analyze_scalar_evolution (loop, rhs2); | |
1802 | chrec1 = chrec_convert (type, chrec1, at_stmt); | |
a0553bff | 1803 | chrec2 = chrec_convert (TREE_TYPE (rhs2), chrec2, at_stmt); |
32e31826 | 1804 | chrec1 = instantiate_parameters (loop, chrec1); |
1805 | chrec2 = instantiate_parameters (loop, chrec2); | |
75a70cf9 | 1806 | res = chrec_fold_plus (type, chrec1, chrec2); |
0de36bdb | 1807 | break; |
1808 | ||
c2c3fd24 | 1809 | case PLUS_EXPR: |
75a70cf9 | 1810 | chrec1 = analyze_scalar_evolution (loop, rhs1); |
1811 | chrec2 = analyze_scalar_evolution (loop, rhs2); | |
1812 | chrec1 = chrec_convert (type, chrec1, at_stmt); | |
1813 | chrec2 = chrec_convert (type, chrec2, at_stmt); | |
32e31826 | 1814 | chrec1 = instantiate_parameters (loop, chrec1); |
1815 | chrec2 = instantiate_parameters (loop, chrec2); | |
75a70cf9 | 1816 | res = chrec_fold_plus (type, chrec1, chrec2); |
c2c3fd24 | 1817 | break; |
48e1416a | 1818 | |
c2c3fd24 | 1819 | case MINUS_EXPR: |
75a70cf9 | 1820 | chrec1 = analyze_scalar_evolution (loop, rhs1); |
1821 | chrec2 = analyze_scalar_evolution (loop, rhs2); | |
1822 | chrec1 = chrec_convert (type, chrec1, at_stmt); | |
1823 | chrec2 = chrec_convert (type, chrec2, at_stmt); | |
32e31826 | 1824 | chrec1 = instantiate_parameters (loop, chrec1); |
1825 | chrec2 = instantiate_parameters (loop, chrec2); | |
75a70cf9 | 1826 | res = chrec_fold_minus (type, chrec1, chrec2); |
c2c3fd24 | 1827 | break; |
1828 | ||
1829 | case NEGATE_EXPR: | |
75a70cf9 | 1830 | chrec1 = analyze_scalar_evolution (loop, rhs1); |
1831 | chrec1 = chrec_convert (type, chrec1, at_stmt); | |
560af66a | 1832 | /* TYPE may be integer, real or complex, so use fold_convert. */ |
32e31826 | 1833 | chrec1 = instantiate_parameters (loop, chrec1); |
75a70cf9 | 1834 | res = chrec_fold_multiply (type, chrec1, |
560af66a | 1835 | fold_convert (type, integer_minus_one_node)); |
c2c3fd24 | 1836 | break; |
1837 | ||
b6eab06c | 1838 | case BIT_NOT_EXPR: |
1839 | /* Handle ~X as -1 - X. */ | |
1840 | chrec1 = analyze_scalar_evolution (loop, rhs1); | |
1841 | chrec1 = chrec_convert (type, chrec1, at_stmt); | |
32e31826 | 1842 | chrec1 = instantiate_parameters (loop, chrec1); |
b6eab06c | 1843 | res = chrec_fold_minus (type, |
1844 | fold_convert (type, integer_minus_one_node), | |
1845 | chrec1); | |
1846 | break; | |
1847 | ||
c2c3fd24 | 1848 | case MULT_EXPR: |
75a70cf9 | 1849 | chrec1 = analyze_scalar_evolution (loop, rhs1); |
1850 | chrec2 = analyze_scalar_evolution (loop, rhs2); | |
1851 | chrec1 = chrec_convert (type, chrec1, at_stmt); | |
1852 | chrec2 = chrec_convert (type, chrec2, at_stmt); | |
32e31826 | 1853 | chrec1 = instantiate_parameters (loop, chrec1); |
1854 | chrec2 = instantiate_parameters (loop, chrec2); | |
75a70cf9 | 1855 | res = chrec_fold_multiply (type, chrec1, chrec2); |
88dbf20f | 1856 | break; |
48e1416a | 1857 | |
72dd6141 | 1858 | CASE_CONVERT: |
3ef23449 | 1859 | /* In case we have a truncation of a widened operation that in |
1860 | the truncated type has undefined overflow behavior analyze | |
1861 | the operation done in an unsigned type of the same precision | |
1862 | as the final truncation. We cannot derive a scalar evolution | |
1863 | for the widened operation but for the truncated result. */ | |
1864 | if (TREE_CODE (type) == INTEGER_TYPE | |
1865 | && TREE_CODE (TREE_TYPE (rhs1)) == INTEGER_TYPE | |
1866 | && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (rhs1)) | |
1867 | && TYPE_OVERFLOW_UNDEFINED (type) | |
1868 | && TREE_CODE (rhs1) == SSA_NAME | |
1869 | && (def = SSA_NAME_DEF_STMT (rhs1)) | |
1870 | && is_gimple_assign (def) | |
1871 | && TREE_CODE_CLASS (gimple_assign_rhs_code (def)) == tcc_binary | |
1872 | && TREE_CODE (gimple_assign_rhs2 (def)) == INTEGER_CST) | |
1873 | { | |
1874 | tree utype = unsigned_type_for (type); | |
1875 | chrec1 = interpret_rhs_expr (loop, at_stmt, utype, | |
1876 | gimple_assign_rhs1 (def), | |
1877 | gimple_assign_rhs_code (def), | |
1878 | gimple_assign_rhs2 (def)); | |
1879 | } | |
1880 | else | |
1881 | chrec1 = analyze_scalar_evolution (loop, rhs1); | |
75a70cf9 | 1882 | res = chrec_convert (type, chrec1, at_stmt); |
c2c3fd24 | 1883 | break; |
48e1416a | 1884 | |
c2c3fd24 | 1885 | default: |
1886 | res = chrec_dont_know; | |
1887 | break; | |
1888 | } | |
48e1416a | 1889 | |
c2c3fd24 | 1890 | return res; |
1891 | } | |
1892 | ||
75a70cf9 | 1893 | /* Interpret the expression EXPR. */ |
1894 | ||
1895 | static tree | |
1896 | interpret_expr (struct loop *loop, gimple at_stmt, tree expr) | |
1897 | { | |
1898 | enum tree_code code; | |
1899 | tree type = TREE_TYPE (expr), op0, op1; | |
1900 | ||
1901 | if (automatically_generated_chrec_p (expr)) | |
1902 | return expr; | |
1903 | ||
8a2caf10 | 1904 | if (TREE_CODE (expr) == POLYNOMIAL_CHREC |
1905 | || get_gimple_rhs_class (TREE_CODE (expr)) == GIMPLE_TERNARY_RHS) | |
75a70cf9 | 1906 | return chrec_dont_know; |
1907 | ||
1908 | extract_ops_from_tree (expr, &code, &op0, &op1); | |
1909 | ||
1910 | return interpret_rhs_expr (loop, at_stmt, type, | |
1911 | op0, code, op1); | |
1912 | } | |
1913 | ||
1914 | /* Interpret the rhs of the assignment STMT. */ | |
1915 | ||
1916 | static tree | |
1917 | interpret_gimple_assign (struct loop *loop, gimple stmt) | |
1918 | { | |
1919 | tree type = TREE_TYPE (gimple_assign_lhs (stmt)); | |
1920 | enum tree_code code = gimple_assign_rhs_code (stmt); | |
1921 | ||
1922 | return interpret_rhs_expr (loop, stmt, type, | |
1923 | gimple_assign_rhs1 (stmt), code, | |
1924 | gimple_assign_rhs2 (stmt)); | |
1925 | } | |
1926 | ||
c2c3fd24 | 1927 | \f |
1928 | ||
48e1416a | 1929 | /* This section contains all the entry points: |
c2c3fd24 | 1930 | - number_of_iterations_in_loop, |
1931 | - analyze_scalar_evolution, | |
1932 | - instantiate_parameters. | |
1933 | */ | |
1934 | ||
1935 | /* Compute and return the evolution function in WRTO_LOOP, the nearest | |
1936 | common ancestor of DEF_LOOP and USE_LOOP. */ | |
1937 | ||
48e1416a | 1938 | static tree |
1939 | compute_scalar_evolution_in_loop (struct loop *wrto_loop, | |
1940 | struct loop *def_loop, | |
c2c3fd24 | 1941 | tree ev) |
1942 | { | |
a05095f9 | 1943 | bool val; |
c2c3fd24 | 1944 | tree res; |
a05095f9 | 1945 | |
c2c3fd24 | 1946 | if (def_loop == wrto_loop) |
1947 | return ev; | |
1948 | ||
9e3536f4 | 1949 | def_loop = superloop_at_depth (def_loop, loop_depth (wrto_loop) + 1); |
c2c3fd24 | 1950 | res = compute_overall_effect_of_inner_loop (def_loop, ev); |
1951 | ||
a05095f9 | 1952 | if (no_evolution_in_loop_p (res, wrto_loop->num, &val) && val) |
1953 | return res; | |
1954 | ||
c2c3fd24 | 1955 | return analyze_scalar_evolution_1 (wrto_loop, res, chrec_not_analyzed_yet); |
1956 | } | |
1957 | ||
1958 | /* Helper recursive function. */ | |
1959 | ||
1960 | static tree | |
1961 | analyze_scalar_evolution_1 (struct loop *loop, tree var, tree res) | |
1962 | { | |
75a70cf9 | 1963 | tree type = TREE_TYPE (var); |
1964 | gimple def; | |
c2c3fd24 | 1965 | basic_block bb; |
1966 | struct loop *def_loop; | |
1967 | ||
a8c839ae | 1968 | if (loop == NULL || TREE_CODE (type) == VECTOR_TYPE) |
c2c3fd24 | 1969 | return chrec_dont_know; |
1970 | ||
1971 | if (TREE_CODE (var) != SSA_NAME) | |
75a70cf9 | 1972 | return interpret_expr (loop, NULL, var); |
c2c3fd24 | 1973 | |
1974 | def = SSA_NAME_DEF_STMT (var); | |
75a70cf9 | 1975 | bb = gimple_bb (def); |
c2c3fd24 | 1976 | def_loop = bb ? bb->loop_father : NULL; |
1977 | ||
1978 | if (bb == NULL | |
1979 | || !flow_bb_inside_loop_p (loop, bb)) | |
1980 | { | |
1981 | /* Keep the symbolic form. */ | |
1982 | res = var; | |
1983 | goto set_and_end; | |
1984 | } | |
1985 | ||
1986 | if (res != chrec_not_analyzed_yet) | |
1987 | { | |
1988 | if (loop != bb->loop_father) | |
48e1416a | 1989 | res = compute_scalar_evolution_in_loop |
c2c3fd24 | 1990 | (find_common_loop (loop, bb->loop_father), bb->loop_father, res); |
1991 | ||
1992 | goto set_and_end; | |
1993 | } | |
1994 | ||
1995 | if (loop != def_loop) | |
1996 | { | |
1997 | res = analyze_scalar_evolution_1 (def_loop, var, chrec_not_analyzed_yet); | |
1998 | res = compute_scalar_evolution_in_loop (loop, def_loop, res); | |
1999 | ||
2000 | goto set_and_end; | |
2001 | } | |
2002 | ||
75a70cf9 | 2003 | switch (gimple_code (def)) |
c2c3fd24 | 2004 | { |
75a70cf9 | 2005 | case GIMPLE_ASSIGN: |
2006 | res = interpret_gimple_assign (loop, def); | |
c2c3fd24 | 2007 | break; |
2008 | ||
75a70cf9 | 2009 | case GIMPLE_PHI: |
c2c3fd24 | 2010 | if (loop_phi_node_p (def)) |
1a91d914 | 2011 | res = interpret_loop_phi (loop, as_a <gphi *> (def)); |
c2c3fd24 | 2012 | else |
1a91d914 | 2013 | res = interpret_condition_phi (loop, as_a <gphi *> (def)); |
c2c3fd24 | 2014 | break; |
2015 | ||
2016 | default: | |
2017 | res = chrec_dont_know; | |
2018 | break; | |
2019 | } | |
2020 | ||
2021 | set_and_end: | |
2022 | ||
2023 | /* Keep the symbolic form. */ | |
2024 | if (res == chrec_dont_know) | |
2025 | res = var; | |
2026 | ||
2027 | if (loop == def_loop) | |
089aa668 | 2028 | set_scalar_evolution (block_before_loop (loop), var, res); |
c2c3fd24 | 2029 | |
2030 | return res; | |
2031 | } | |
2032 | ||
8b7d09b4 | 2033 | /* Analyzes and returns the scalar evolution of the ssa_name VAR in |
2034 | LOOP. LOOP is the loop in which the variable is used. | |
48e1416a | 2035 | |
c2c3fd24 | 2036 | Example of use: having a pointer VAR to a SSA_NAME node, STMT a |
2037 | pointer to the statement that uses this variable, in order to | |
2038 | determine the evolution function of the variable, use the following | |
2039 | calls: | |
48e1416a | 2040 | |
8b7d09b4 | 2041 | loop_p loop = loop_containing_stmt (stmt); |
2042 | tree chrec_with_symbols = analyze_scalar_evolution (loop, var); | |
afd80ffb | 2043 | tree chrec_instantiated = instantiate_parameters (loop, chrec_with_symbols); |
c2c3fd24 | 2044 | */ |
2045 | ||
48e1416a | 2046 | tree |
c2c3fd24 | 2047 | analyze_scalar_evolution (struct loop *loop, tree var) |
2048 | { | |
2049 | tree res; | |
2050 | ||
487a9bc1 | 2051 | if (dump_file && (dump_flags & TDF_SCEV)) |
c2c3fd24 | 2052 | { |
2053 | fprintf (dump_file, "(analyze_scalar_evolution \n"); | |
2054 | fprintf (dump_file, " (loop_nb = %d)\n", loop->num); | |
2055 | fprintf (dump_file, " (scalar = "); | |
2056 | print_generic_expr (dump_file, var, 0); | |
2057 | fprintf (dump_file, ")\n"); | |
2058 | } | |
2059 | ||
089aa668 | 2060 | res = get_scalar_evolution (block_before_loop (loop), var); |
2061 | res = analyze_scalar_evolution_1 (loop, var, res); | |
c2c3fd24 | 2062 | |
487a9bc1 | 2063 | if (dump_file && (dump_flags & TDF_SCEV)) |
c2c3fd24 | 2064 | fprintf (dump_file, ")\n"); |
2065 | ||
2066 | return res; | |
2067 | } | |
2068 | ||
62bc06ea | 2069 | /* Analyzes and returns the scalar evolution of VAR address in LOOP. */ |
2070 | ||
2071 | static tree | |
2072 | analyze_scalar_evolution_for_address_of (struct loop *loop, tree var) | |
2073 | { | |
2074 | return analyze_scalar_evolution (loop, build_fold_addr_expr (var)); | |
2075 | } | |
2076 | ||
c2c3fd24 | 2077 | /* Analyze scalar evolution of use of VERSION in USE_LOOP with respect to |
76610704 | 2078 | WRTO_LOOP (which should be a superloop of USE_LOOP) |
553b9523 | 2079 | |
2080 | FOLDED_CASTS is set to true if resolve_mixers used | |
2081 | chrec_convert_aggressive (TODO -- not really, we are way too conservative | |
48e1416a | 2082 | at the moment in order to keep things simple). |
2083 | ||
76610704 | 2084 | To illustrate the meaning of USE_LOOP and WRTO_LOOP, consider the following |
2085 | example: | |
2086 | ||
2087 | for (i = 0; i < 100; i++) -- loop 1 | |
2088 | { | |
2089 | for (j = 0; j < 100; j++) -- loop 2 | |
2090 | { | |
2091 | k1 = i; | |
2092 | k2 = j; | |
2093 | ||
2094 | use2 (k1, k2); | |
2095 | ||
2096 | for (t = 0; t < 100; t++) -- loop 3 | |
2097 | use3 (k1, k2); | |
2098 | ||
2099 | } | |
2100 | use1 (k1, k2); | |
2101 | } | |
2102 | ||
2103 | Both k1 and k2 are invariants in loop3, thus | |
2104 | analyze_scalar_evolution_in_loop (loop3, loop3, k1) = k1 | |
2105 | analyze_scalar_evolution_in_loop (loop3, loop3, k2) = k2 | |
2106 | ||
2107 | As they are invariant, it does not matter whether we consider their | |
2108 | usage in loop 3 or loop 2, hence | |
2109 | analyze_scalar_evolution_in_loop (loop2, loop3, k1) = | |
2110 | analyze_scalar_evolution_in_loop (loop2, loop2, k1) = i | |
2111 | analyze_scalar_evolution_in_loop (loop2, loop3, k2) = | |
2112 | analyze_scalar_evolution_in_loop (loop2, loop2, k2) = [0,+,1]_2 | |
2113 | ||
2114 | Similarly for their evolutions with respect to loop 1. The values of K2 | |
2115 | in the use in loop 2 vary independently on loop 1, thus we cannot express | |
2116 | the evolution with respect to loop 1: | |
2117 | analyze_scalar_evolution_in_loop (loop1, loop3, k1) = | |
2118 | analyze_scalar_evolution_in_loop (loop1, loop2, k1) = [0,+,1]_1 | |
2119 | analyze_scalar_evolution_in_loop (loop1, loop3, k2) = | |
2120 | analyze_scalar_evolution_in_loop (loop1, loop2, k2) = dont_know | |
2121 | ||
2122 | The value of k2 in the use in loop 1 is known, though: | |
2123 | analyze_scalar_evolution_in_loop (loop1, loop1, k1) = [0,+,1]_1 | |
2124 | analyze_scalar_evolution_in_loop (loop1, loop1, k2) = 100 | |
2125 | */ | |
c2c3fd24 | 2126 | |
2127 | static tree | |
2128 | analyze_scalar_evolution_in_loop (struct loop *wrto_loop, struct loop *use_loop, | |
553b9523 | 2129 | tree version, bool *folded_casts) |
c2c3fd24 | 2130 | { |
2131 | bool val = false; | |
553b9523 | 2132 | tree ev = version, tmp; |
c2c3fd24 | 2133 | |
48e1416a | 2134 | /* We cannot just do |
76610704 | 2135 | |
2136 | tmp = analyze_scalar_evolution (use_loop, version); | |
2137 | ev = resolve_mixers (wrto_loop, tmp); | |
2138 | ||
2139 | as resolve_mixers would query the scalar evolution with respect to | |
2140 | wrto_loop. For example, in the situation described in the function | |
2141 | comment, suppose that wrto_loop = loop1, use_loop = loop3 and | |
2142 | version = k2. Then | |
2143 | ||
2144 | analyze_scalar_evolution (use_loop, version) = k2 | |
2145 | ||
2146 | and resolve_mixers (loop1, k2) finds that the value of k2 in loop 1 | |
2147 | is 100, which is a wrong result, since we are interested in the | |
2148 | value in loop 3. | |
2149 | ||
2150 | Instead, we need to proceed from use_loop to wrto_loop loop by loop, | |
2151 | each time checking that there is no evolution in the inner loop. */ | |
2152 | ||
553b9523 | 2153 | if (folded_casts) |
2154 | *folded_casts = false; | |
c2c3fd24 | 2155 | while (1) |
2156 | { | |
553b9523 | 2157 | tmp = analyze_scalar_evolution (use_loop, ev); |
2158 | ev = resolve_mixers (use_loop, tmp); | |
2159 | ||
2160 | if (folded_casts && tmp != ev) | |
2161 | *folded_casts = true; | |
c2c3fd24 | 2162 | |
2163 | if (use_loop == wrto_loop) | |
2164 | return ev; | |
2165 | ||
2166 | /* If the value of the use changes in the inner loop, we cannot express | |
2167 | its value in the outer loop (we might try to return interval chrec, | |
2168 | but we do not have a user for it anyway) */ | |
2169 | if (!no_evolution_in_loop_p (ev, use_loop->num, &val) | |
2170 | || !val) | |
2171 | return chrec_dont_know; | |
2172 | ||
9e3536f4 | 2173 | use_loop = loop_outer (use_loop); |
c2c3fd24 | 2174 | } |
2175 | } | |
2176 | ||
15a951ca | 2177 | |
e23d3784 | 2178 | /* Hashtable helpers for a temporary hash-table used when |
2179 | instantiating a CHREC or resolving mixers. For this use | |
2180 | instantiated_below is always the same. */ | |
2181 | ||
e23d3784 | 2182 | struct instantiate_cache_type |
15a951ca | 2183 | { |
cbb69ef1 | 2184 | htab_t map; |
2185 | vec<scev_info_str> entries; | |
48e1416a | 2186 | |
9af5ce0c | 2187 | instantiate_cache_type () : map (NULL), entries (vNULL) {} |
e23d3784 | 2188 | ~instantiate_cache_type (); |
32e31826 | 2189 | tree get (unsigned slot) { return entries[slot].chrec; } |
2190 | void set (unsigned slot, tree chrec) { entries[slot].chrec = chrec; } | |
e23d3784 | 2191 | }; |
15a951ca | 2192 | |
e23d3784 | 2193 | instantiate_cache_type::~instantiate_cache_type () |
2194 | { | |
32e31826 | 2195 | if (map != NULL) |
e23d3784 | 2196 | { |
cbb69ef1 | 2197 | htab_delete (map); |
e23d3784 | 2198 | entries.release (); |
2199 | } | |
15a951ca | 2200 | } |
2201 | ||
cbb69ef1 | 2202 | /* Cache to avoid infinite recursion when instantiating an SSA name. |
2203 | Live during the outermost instantiate_scev or resolve_mixers call. */ | |
2204 | static instantiate_cache_type *global_cache; | |
2205 | ||
2206 | /* Computes a hash function for database element ELT. */ | |
2207 | ||
2208 | static inline hashval_t | |
2209 | hash_idx_scev_info (const void *elt_) | |
2210 | { | |
2211 | unsigned idx = ((size_t) elt_) - 2; | |
2212 | return hash_scev_info (&global_cache->entries[idx]); | |
2213 | } | |
2214 | ||
2215 | /* Compares database elements E1 and E2. */ | |
2216 | ||
2217 | static inline int | |
2218 | eq_idx_scev_info (const void *e1, const void *e2) | |
2219 | { | |
2220 | unsigned idx1 = ((size_t) e1) - 2; | |
2221 | return eq_scev_info (&global_cache->entries[idx1], e2); | |
2222 | } | |
2223 | ||
32e31826 | 2224 | /* Returns from CACHE the slot number of the cached chrec for NAME. */ |
e23d3784 | 2225 | |
32e31826 | 2226 | static unsigned |
cbb69ef1 | 2227 | get_instantiated_value_entry (instantiate_cache_type &cache, |
2228 | tree name, basic_block instantiate_below) | |
e23d3784 | 2229 | { |
32e31826 | 2230 | if (!cache.map) |
e23d3784 | 2231 | { |
cbb69ef1 | 2232 | cache.map = htab_create (10, hash_idx_scev_info, eq_idx_scev_info, NULL); |
e23d3784 | 2233 | cache.entries.create (10); |
2234 | } | |
48e1416a | 2235 | |
cbb69ef1 | 2236 | scev_info_str e; |
2237 | e.name_version = SSA_NAME_VERSION (name); | |
2238 | e.instantiated_below = instantiate_below->index; | |
2239 | void **slot = htab_find_slot_with_hash (cache.map, &e, | |
2240 | hash_scev_info (&e), INSERT); | |
2241 | if (!*slot) | |
e23d3784 | 2242 | { |
2243 | e.chrec = chrec_not_analyzed_yet; | |
cbb69ef1 | 2244 | *slot = (void *)(size_t)(cache.entries.length () + 2); |
e23d3784 | 2245 | cache.entries.safe_push (e); |
e23d3784 | 2246 | } |
2247 | ||
cbb69ef1 | 2248 | return ((size_t)*slot) - 2; |
15a951ca | 2249 | } |
2250 | ||
32e31826 | 2251 | |
9887dd18 | 2252 | /* Return the closed_loop_phi node for VAR. If there is none, return |
2253 | NULL_TREE. */ | |
2254 | ||
2255 | static tree | |
2256 | loop_closed_phi_def (tree var) | |
2257 | { | |
2258 | struct loop *loop; | |
2259 | edge exit; | |
1a91d914 | 2260 | gphi *phi; |
2261 | gphi_iterator psi; | |
9887dd18 | 2262 | |
2263 | if (var == NULL_TREE | |
2264 | || TREE_CODE (var) != SSA_NAME) | |
2265 | return NULL_TREE; | |
2266 | ||
2267 | loop = loop_containing_stmt (SSA_NAME_DEF_STMT (var)); | |
d9e7e1a2 | 2268 | exit = single_exit (loop); |
9887dd18 | 2269 | if (!exit) |
2270 | return NULL_TREE; | |
2271 | ||
75a70cf9 | 2272 | for (psi = gsi_start_phis (exit->dest); !gsi_end_p (psi); gsi_next (&psi)) |
2273 | { | |
1a91d914 | 2274 | phi = psi.phi (); |
75a70cf9 | 2275 | if (PHI_ARG_DEF_FROM_EDGE (phi, exit) == var) |
2276 | return PHI_RESULT (phi); | |
2277 | } | |
9887dd18 | 2278 | |
2279 | return NULL_TREE; | |
2280 | } | |
2281 | ||
6ee802ad | 2282 | static tree instantiate_scev_r (basic_block, struct loop *, struct loop *, |
32e31826 | 2283 | tree, bool, int); |
0731d869 | 2284 | |
2285 | /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW | |
2286 | and EVOLUTION_LOOP, that were left under a symbolic form. | |
2287 | ||
5e803fbe | 2288 | CHREC is an SSA_NAME to be instantiated. |
0731d869 | 2289 | |
2290 | CACHE is the cache of already instantiated values. | |
2291 | ||
2292 | FOLD_CONVERSIONS should be set to true when the conversions that | |
2293 | may wrap in signed/pointer type are folded, as long as the value of | |
2294 | the chrec is preserved. | |
2295 | ||
2296 | SIZE_EXPR is used for computing the size of the expression to be | |
2297 | instantiated, and to stop if it exceeds some limit. */ | |
2298 | ||
2299 | static tree | |
5e803fbe | 2300 | instantiate_scev_name (basic_block instantiate_below, |
6ee802ad | 2301 | struct loop *evolution_loop, struct loop *inner_loop, |
2302 | tree chrec, | |
32e31826 | 2303 | bool fold_conversions, |
d9dd21a8 | 2304 | int size_expr) |
0731d869 | 2305 | { |
5e803fbe | 2306 | tree res; |
2307 | struct loop *def_loop; | |
2308 | basic_block def_bb = gimple_bb (SSA_NAME_DEF_STMT (chrec)); | |
c43f1e90 | 2309 | |
5e803fbe | 2310 | /* A parameter (or loop invariant and we do not want to include |
2311 | evolutions in outer loops), nothing to do. */ | |
2312 | if (!def_bb | |
2313 | || loop_depth (def_bb->loop_father) == 0 | |
2314 | || dominated_by_p (CDI_DOMINATORS, instantiate_below, def_bb)) | |
2315 | return chrec; | |
c43f1e90 | 2316 | |
5e803fbe | 2317 | /* We cache the value of instantiated variable to avoid exponential |
2318 | time complexity due to reevaluations. We also store the convenient | |
2319 | value in the cache in order to prevent infinite recursion -- we do | |
2320 | not want to instantiate the SSA_NAME if it is in a mixer | |
2321 | structure. This is used for avoiding the instantiation of | |
2322 | recursively defined functions, such as: | |
0731d869 | 2323 | |
5e803fbe | 2324 | | a_2 -> {0, +, 1, +, a_2}_1 */ |
c43f1e90 | 2325 | |
cbb69ef1 | 2326 | unsigned si = get_instantiated_value_entry (*global_cache, |
2327 | chrec, instantiate_below); | |
32e31826 | 2328 | if (global_cache->get (si) != chrec_not_analyzed_yet) |
2329 | return global_cache->get (si); | |
c43f1e90 | 2330 | |
e23d3784 | 2331 | /* On recursion return chrec_dont_know. */ |
32e31826 | 2332 | global_cache->set (si, chrec_dont_know); |
0731d869 | 2333 | |
5e803fbe | 2334 | def_loop = find_common_loop (evolution_loop, def_bb->loop_father); |
2335 | ||
0731d869 | 2336 | /* If the analysis yields a parametric chrec, instantiate the |
2337 | result again. */ | |
2338 | res = analyze_scalar_evolution (def_loop, chrec); | |
2339 | ||
52f57b4e | 2340 | /* Don't instantiate default definitions. */ |
0731d869 | 2341 | if (TREE_CODE (res) == SSA_NAME |
52f57b4e | 2342 | && SSA_NAME_IS_DEFAULT_DEF (res)) |
2343 | ; | |
2344 | ||
2345 | /* Don't instantiate loop-closed-ssa phi nodes. */ | |
2346 | else if (TREE_CODE (res) == SSA_NAME | |
2347 | && loop_depth (loop_containing_stmt (SSA_NAME_DEF_STMT (res))) | |
2348 | > loop_depth (def_loop)) | |
0731d869 | 2349 | { |
2350 | if (res == chrec) | |
2351 | res = loop_closed_phi_def (chrec); | |
2352 | else | |
2353 | res = chrec; | |
2354 | ||
dfeb6545 | 2355 | /* When there is no loop_closed_phi_def, it means that the |
2356 | variable is not used after the loop: try to still compute the | |
2357 | value of the variable when exiting the loop. */ | |
2358 | if (res == NULL_TREE) | |
2359 | { | |
2360 | loop_p loop = loop_containing_stmt (SSA_NAME_DEF_STMT (chrec)); | |
2361 | res = analyze_scalar_evolution (loop, chrec); | |
2362 | res = compute_overall_effect_of_inner_loop (loop, res); | |
6ee802ad | 2363 | res = instantiate_scev_r (instantiate_below, evolution_loop, |
2364 | inner_loop, res, | |
32e31826 | 2365 | fold_conversions, size_expr); |
dfeb6545 | 2366 | } |
2367 | else if (!dominated_by_p (CDI_DOMINATORS, instantiate_below, | |
2368 | gimple_bb (SSA_NAME_DEF_STMT (res)))) | |
0731d869 | 2369 | res = chrec_dont_know; |
2370 | } | |
2371 | ||
2372 | else if (res != chrec_dont_know) | |
6ee802ad | 2373 | { |
2374 | if (inner_loop | |
0c763224 | 2375 | && def_bb->loop_father != inner_loop |
6ee802ad | 2376 | && !flow_loop_nested_p (def_bb->loop_father, inner_loop)) |
2377 | /* ??? We could try to compute the overall effect of the loop here. */ | |
2378 | res = chrec_dont_know; | |
2379 | else | |
2380 | res = instantiate_scev_r (instantiate_below, evolution_loop, | |
2381 | inner_loop, res, | |
32e31826 | 2382 | fold_conversions, size_expr); |
6ee802ad | 2383 | } |
0731d869 | 2384 | |
2385 | /* Store the correct value to the cache. */ | |
32e31826 | 2386 | global_cache->set (si, res); |
0731d869 | 2387 | return res; |
0731d869 | 2388 | } |
2389 | ||
a819f845 | 2390 | /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW |
2391 | and EVOLUTION_LOOP, that were left under a symbolic form. | |
2392 | ||
2393 | CHREC is a polynomial chain of recurrence to be instantiated. | |
2394 | ||
2395 | CACHE is the cache of already instantiated values. | |
2396 | ||
2397 | FOLD_CONVERSIONS should be set to true when the conversions that | |
2398 | may wrap in signed/pointer type are folded, as long as the value of | |
2399 | the chrec is preserved. | |
2400 | ||
2401 | SIZE_EXPR is used for computing the size of the expression to be | |
2402 | instantiated, and to stop if it exceeds some limit. */ | |
2403 | ||
2404 | static tree | |
2405 | instantiate_scev_poly (basic_block instantiate_below, | |
6ee802ad | 2406 | struct loop *evolution_loop, struct loop *, |
32e31826 | 2407 | tree chrec, bool fold_conversions, int size_expr) |
a819f845 | 2408 | { |
2409 | tree op1; | |
d91a99f1 | 2410 | tree op0 = instantiate_scev_r (instantiate_below, evolution_loop, |
6ee802ad | 2411 | get_chrec_loop (chrec), |
32e31826 | 2412 | CHREC_LEFT (chrec), fold_conversions, |
a819f845 | 2413 | size_expr); |
2414 | if (op0 == chrec_dont_know) | |
2415 | return chrec_dont_know; | |
2416 | ||
d91a99f1 | 2417 | op1 = instantiate_scev_r (instantiate_below, evolution_loop, |
6ee802ad | 2418 | get_chrec_loop (chrec), |
32e31826 | 2419 | CHREC_RIGHT (chrec), fold_conversions, |
a819f845 | 2420 | size_expr); |
2421 | if (op1 == chrec_dont_know) | |
2422 | return chrec_dont_know; | |
2423 | ||
2424 | if (CHREC_LEFT (chrec) != op0 | |
2425 | || CHREC_RIGHT (chrec) != op1) | |
2426 | { | |
2427 | op1 = chrec_convert_rhs (chrec_type (op0), op1, NULL); | |
6ee802ad | 2428 | chrec = build_polynomial_chrec (CHREC_VARIABLE (chrec), op0, op1); |
a819f845 | 2429 | } |
1d4dd1ed | 2430 | |
a819f845 | 2431 | return chrec; |
2432 | } | |
2433 | ||
5a10dfba | 2434 | /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW |
2435 | and EVOLUTION_LOOP, that were left under a symbolic form. | |
2436 | ||
9e9aa0c6 | 2437 | "C0 CODE C1" is a binary expression of type TYPE to be instantiated. |
5a10dfba | 2438 | |
2439 | CACHE is the cache of already instantiated values. | |
2440 | ||
2441 | FOLD_CONVERSIONS should be set to true when the conversions that | |
2442 | may wrap in signed/pointer type are folded, as long as the value of | |
2443 | the chrec is preserved. | |
2444 | ||
2445 | SIZE_EXPR is used for computing the size of the expression to be | |
2446 | instantiated, and to stop if it exceeds some limit. */ | |
2447 | ||
2448 | static tree | |
2449 | instantiate_scev_binary (basic_block instantiate_below, | |
6ee802ad | 2450 | struct loop *evolution_loop, struct loop *inner_loop, |
2451 | tree chrec, enum tree_code code, | |
9e9aa0c6 | 2452 | tree type, tree c0, tree c1, |
32e31826 | 2453 | bool fold_conversions, int size_expr) |
5a10dfba | 2454 | { |
2455 | tree op1; | |
6ee802ad | 2456 | tree op0 = instantiate_scev_r (instantiate_below, evolution_loop, inner_loop, |
32e31826 | 2457 | c0, fold_conversions, size_expr); |
5a10dfba | 2458 | if (op0 == chrec_dont_know) |
2459 | return chrec_dont_know; | |
2460 | ||
6ee802ad | 2461 | op1 = instantiate_scev_r (instantiate_below, evolution_loop, inner_loop, |
32e31826 | 2462 | c1, fold_conversions, size_expr); |
5a10dfba | 2463 | if (op1 == chrec_dont_know) |
2464 | return chrec_dont_know; | |
2465 | ||
9e9aa0c6 | 2466 | if (c0 != op0 |
2467 | || c1 != op1) | |
5a10dfba | 2468 | { |
5a10dfba | 2469 | op0 = chrec_convert (type, op0, NULL); |
2470 | op1 = chrec_convert_rhs (type, op1, NULL); | |
2471 | ||
9e9aa0c6 | 2472 | switch (code) |
5a10dfba | 2473 | { |
2474 | case POINTER_PLUS_EXPR: | |
2475 | case PLUS_EXPR: | |
2476 | return chrec_fold_plus (type, op0, op1); | |
2477 | ||
2478 | case MINUS_EXPR: | |
2479 | return chrec_fold_minus (type, op0, op1); | |
2480 | ||
2481 | case MULT_EXPR: | |
2482 | return chrec_fold_multiply (type, op0, op1); | |
2483 | ||
2484 | default: | |
2485 | gcc_unreachable (); | |
2486 | } | |
2487 | } | |
2488 | ||
9e9aa0c6 | 2489 | return chrec ? chrec : fold_build2 (code, type, c0, c1); |
5a10dfba | 2490 | } |
2491 | ||
3e0b5bba | 2492 | /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW |
2493 | and EVOLUTION_LOOP, that were left under a symbolic form. | |
2494 | ||
2495 | "CHREC" is an array reference to be instantiated. | |
2496 | ||
2497 | CACHE is the cache of already instantiated values. | |
2498 | ||
2499 | FOLD_CONVERSIONS should be set to true when the conversions that | |
2500 | may wrap in signed/pointer type are folded, as long as the value of | |
2501 | the chrec is preserved. | |
2502 | ||
2503 | SIZE_EXPR is used for computing the size of the expression to be | |
2504 | instantiated, and to stop if it exceeds some limit. */ | |
2505 | ||
2506 | static tree | |
2507 | instantiate_array_ref (basic_block instantiate_below, | |
6ee802ad | 2508 | struct loop *evolution_loop, struct loop *inner_loop, |
32e31826 | 2509 | tree chrec, bool fold_conversions, int size_expr) |
3e0b5bba | 2510 | { |
2511 | tree res; | |
2512 | tree index = TREE_OPERAND (chrec, 1); | |
6ee802ad | 2513 | tree op1 = instantiate_scev_r (instantiate_below, evolution_loop, |
2514 | inner_loop, index, | |
32e31826 | 2515 | fold_conversions, size_expr); |
3e0b5bba | 2516 | |
2517 | if (op1 == chrec_dont_know) | |
2518 | return chrec_dont_know; | |
2519 | ||
2520 | if (chrec && op1 == index) | |
2521 | return chrec; | |
2522 | ||
2523 | res = unshare_expr (chrec); | |
2524 | TREE_OPERAND (res, 1) = op1; | |
2525 | return res; | |
2526 | } | |
2527 | ||
089aa668 | 2528 | /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW |
7723692a | 2529 | and EVOLUTION_LOOP, that were left under a symbolic form. |
2530 | ||
2531 | "CHREC" that stands for a convert expression "(TYPE) OP" is to be | |
2532 | instantiated. | |
2533 | ||
2534 | CACHE is the cache of already instantiated values. | |
2535 | ||
2536 | FOLD_CONVERSIONS should be set to true when the conversions that | |
2537 | may wrap in signed/pointer type are folded, as long as the value of | |
2538 | the chrec is preserved. | |
2539 | ||
2540 | SIZE_EXPR is used for computing the size of the expression to be | |
2541 | instantiated, and to stop if it exceeds some limit. */ | |
2542 | ||
2543 | static tree | |
2544 | instantiate_scev_convert (basic_block instantiate_below, | |
6ee802ad | 2545 | struct loop *evolution_loop, struct loop *inner_loop, |
32e31826 | 2546 | tree chrec, tree type, tree op, |
2547 | bool fold_conversions, int size_expr) | |
7723692a | 2548 | { |
6ee802ad | 2549 | tree op0 = instantiate_scev_r (instantiate_below, evolution_loop, |
2550 | inner_loop, op, | |
32e31826 | 2551 | fold_conversions, size_expr); |
7723692a | 2552 | |
2553 | if (op0 == chrec_dont_know) | |
2554 | return chrec_dont_know; | |
2555 | ||
2556 | if (fold_conversions) | |
2557 | { | |
2558 | tree tmp = chrec_convert_aggressive (type, op0); | |
2559 | if (tmp) | |
2560 | return tmp; | |
2561 | } | |
2562 | ||
2563 | if (chrec && op0 == op) | |
2564 | return chrec; | |
2565 | ||
2566 | /* If we used chrec_convert_aggressive, we can no longer assume that | |
2567 | signed chrecs do not overflow, as chrec_convert does, so avoid | |
2568 | calling it in that case. */ | |
2569 | if (fold_conversions) | |
2570 | return fold_convert (type, op0); | |
2571 | ||
2572 | return chrec_convert (type, op0, NULL); | |
2573 | } | |
2574 | ||
39251a91 | 2575 | /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW |
2576 | and EVOLUTION_LOOP, that were left under a symbolic form. | |
2577 | ||
9d206f16 | 2578 | CHREC is a BIT_NOT_EXPR or a NEGATE_EXPR expression to be instantiated. |
39251a91 | 2579 | Handle ~X as -1 - X. |
9d206f16 | 2580 | Handle -X as -1 * X. |
39251a91 | 2581 | |
2582 | CACHE is the cache of already instantiated values. | |
2583 | ||
2584 | FOLD_CONVERSIONS should be set to true when the conversions that | |
2585 | may wrap in signed/pointer type are folded, as long as the value of | |
2586 | the chrec is preserved. | |
2587 | ||
2588 | SIZE_EXPR is used for computing the size of the expression to be | |
2589 | instantiated, and to stop if it exceeds some limit. */ | |
2590 | ||
2591 | static tree | |
9d206f16 | 2592 | instantiate_scev_not (basic_block instantiate_below, |
6ee802ad | 2593 | struct loop *evolution_loop, struct loop *inner_loop, |
2594 | tree chrec, | |
c43f1e90 | 2595 | enum tree_code code, tree type, tree op, |
32e31826 | 2596 | bool fold_conversions, int size_expr) |
39251a91 | 2597 | { |
6ee802ad | 2598 | tree op0 = instantiate_scev_r (instantiate_below, evolution_loop, |
2599 | inner_loop, op, | |
32e31826 | 2600 | fold_conversions, size_expr); |
c43f1e90 | 2601 | |
39251a91 | 2602 | if (op0 == chrec_dont_know) |
2603 | return chrec_dont_know; | |
2604 | ||
c43f1e90 | 2605 | if (op != op0) |
39251a91 | 2606 | { |
2607 | op0 = chrec_convert (type, op0, NULL); | |
9d206f16 | 2608 | |
c43f1e90 | 2609 | switch (code) |
9d206f16 | 2610 | { |
2611 | case BIT_NOT_EXPR: | |
2612 | return chrec_fold_minus | |
2613 | (type, fold_convert (type, integer_minus_one_node), op0); | |
2614 | ||
2615 | case NEGATE_EXPR: | |
2616 | return chrec_fold_multiply | |
2617 | (type, fold_convert (type, integer_minus_one_node), op0); | |
2618 | ||
2619 | default: | |
2620 | gcc_unreachable (); | |
2621 | } | |
39251a91 | 2622 | } |
9d206f16 | 2623 | |
c43f1e90 | 2624 | return chrec ? chrec : fold_build1 (code, type, op0); |
39251a91 | 2625 | } |
2626 | ||
378a6626 | 2627 | /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW |
2628 | and EVOLUTION_LOOP, that were left under a symbolic form. | |
2629 | ||
2630 | CHREC is an expression with 3 operands to be instantiated. | |
2631 | ||
2632 | CACHE is the cache of already instantiated values. | |
2633 | ||
2634 | FOLD_CONVERSIONS should be set to true when the conversions that | |
2635 | may wrap in signed/pointer type are folded, as long as the value of | |
2636 | the chrec is preserved. | |
2637 | ||
2638 | SIZE_EXPR is used for computing the size of the expression to be | |
2639 | instantiated, and to stop if it exceeds some limit. */ | |
2640 | ||
2641 | static tree | |
2642 | instantiate_scev_3 (basic_block instantiate_below, | |
6ee802ad | 2643 | struct loop *evolution_loop, struct loop *inner_loop, |
2644 | tree chrec, | |
32e31826 | 2645 | bool fold_conversions, int size_expr) |
378a6626 | 2646 | { |
2647 | tree op1, op2; | |
d91a99f1 | 2648 | tree op0 = instantiate_scev_r (instantiate_below, evolution_loop, |
6ee802ad | 2649 | inner_loop, TREE_OPERAND (chrec, 0), |
32e31826 | 2650 | fold_conversions, size_expr); |
378a6626 | 2651 | if (op0 == chrec_dont_know) |
2652 | return chrec_dont_know; | |
2653 | ||
d91a99f1 | 2654 | op1 = instantiate_scev_r (instantiate_below, evolution_loop, |
6ee802ad | 2655 | inner_loop, TREE_OPERAND (chrec, 1), |
32e31826 | 2656 | fold_conversions, size_expr); |
378a6626 | 2657 | if (op1 == chrec_dont_know) |
2658 | return chrec_dont_know; | |
2659 | ||
d91a99f1 | 2660 | op2 = instantiate_scev_r (instantiate_below, evolution_loop, |
6ee802ad | 2661 | inner_loop, TREE_OPERAND (chrec, 2), |
32e31826 | 2662 | fold_conversions, size_expr); |
378a6626 | 2663 | if (op2 == chrec_dont_know) |
2664 | return chrec_dont_know; | |
2665 | ||
2666 | if (op0 == TREE_OPERAND (chrec, 0) | |
2667 | && op1 == TREE_OPERAND (chrec, 1) | |
2668 | && op2 == TREE_OPERAND (chrec, 2)) | |
2669 | return chrec; | |
2670 | ||
2671 | return fold_build3 (TREE_CODE (chrec), | |
2672 | TREE_TYPE (chrec), op0, op1, op2); | |
2673 | } | |
2674 | ||
7723692a | 2675 | /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW |
2676 | and EVOLUTION_LOOP, that were left under a symbolic form. | |
8ceddf57 | 2677 | |
d91a99f1 | 2678 | CHREC is an expression with 2 operands to be instantiated. |
2679 | ||
2680 | CACHE is the cache of already instantiated values. | |
2681 | ||
2682 | FOLD_CONVERSIONS should be set to true when the conversions that | |
2683 | may wrap in signed/pointer type are folded, as long as the value of | |
2684 | the chrec is preserved. | |
2685 | ||
2686 | SIZE_EXPR is used for computing the size of the expression to be | |
2687 | instantiated, and to stop if it exceeds some limit. */ | |
2688 | ||
2689 | static tree | |
2690 | instantiate_scev_2 (basic_block instantiate_below, | |
6ee802ad | 2691 | struct loop *evolution_loop, struct loop *inner_loop, |
2692 | tree chrec, | |
32e31826 | 2693 | bool fold_conversions, int size_expr) |
d91a99f1 | 2694 | { |
2695 | tree op1; | |
2696 | tree op0 = instantiate_scev_r (instantiate_below, evolution_loop, | |
6ee802ad | 2697 | inner_loop, TREE_OPERAND (chrec, 0), |
32e31826 | 2698 | fold_conversions, size_expr); |
d91a99f1 | 2699 | if (op0 == chrec_dont_know) |
2700 | return chrec_dont_know; | |
2701 | ||
2702 | op1 = instantiate_scev_r (instantiate_below, evolution_loop, | |
6ee802ad | 2703 | inner_loop, TREE_OPERAND (chrec, 1), |
32e31826 | 2704 | fold_conversions, size_expr); |
d91a99f1 | 2705 | if (op1 == chrec_dont_know) |
2706 | return chrec_dont_know; | |
2707 | ||
2708 | if (op0 == TREE_OPERAND (chrec, 0) | |
2709 | && op1 == TREE_OPERAND (chrec, 1)) | |
2710 | return chrec; | |
2711 | ||
2712 | return fold_build2 (TREE_CODE (chrec), TREE_TYPE (chrec), op0, op1); | |
2713 | } | |
2714 | ||
2715 | /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW | |
2716 | and EVOLUTION_LOOP, that were left under a symbolic form. | |
2717 | ||
2718 | CHREC is an expression with 2 operands to be instantiated. | |
8ceddf57 | 2719 | |
2720 | CACHE is the cache of already instantiated values. | |
2721 | ||
2722 | FOLD_CONVERSIONS should be set to true when the conversions that | |
2723 | may wrap in signed/pointer type are folded, as long as the value of | |
2724 | the chrec is preserved. | |
2725 | ||
afd80ffb | 2726 | SIZE_EXPR is used for computing the size of the expression to be |
2727 | instantiated, and to stop if it exceeds some limit. */ | |
7723692a | 2728 | |
c2c3fd24 | 2729 | static tree |
089aa668 | 2730 | instantiate_scev_1 (basic_block instantiate_below, |
6ee802ad | 2731 | struct loop *evolution_loop, struct loop *inner_loop, |
2732 | tree chrec, | |
32e31826 | 2733 | bool fold_conversions, int size_expr) |
c2c3fd24 | 2734 | { |
d91a99f1 | 2735 | tree op0 = instantiate_scev_r (instantiate_below, evolution_loop, |
6ee802ad | 2736 | inner_loop, TREE_OPERAND (chrec, 0), |
32e31826 | 2737 | fold_conversions, size_expr); |
d91a99f1 | 2738 | |
2739 | if (op0 == chrec_dont_know) | |
2740 | return chrec_dont_know; | |
2741 | ||
2742 | if (op0 == TREE_OPERAND (chrec, 0)) | |
2743 | return chrec; | |
2744 | ||
2745 | return fold_build1 (TREE_CODE (chrec), TREE_TYPE (chrec), op0); | |
2746 | } | |
2747 | ||
2748 | /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW | |
2749 | and EVOLUTION_LOOP, that were left under a symbolic form. | |
2750 | ||
2751 | CHREC is the scalar evolution to instantiate. | |
2752 | ||
2753 | CACHE is the cache of already instantiated values. | |
88d02c9e | 2754 | |
d91a99f1 | 2755 | FOLD_CONVERSIONS should be set to true when the conversions that |
2756 | may wrap in signed/pointer type are folded, as long as the value of | |
2757 | the chrec is preserved. | |
2758 | ||
2759 | SIZE_EXPR is used for computing the size of the expression to be | |
2760 | instantiated, and to stop if it exceeds some limit. */ | |
2761 | ||
2762 | static tree | |
2763 | instantiate_scev_r (basic_block instantiate_below, | |
6ee802ad | 2764 | struct loop *evolution_loop, struct loop *inner_loop, |
2765 | tree chrec, | |
32e31826 | 2766 | bool fold_conversions, int size_expr) |
d91a99f1 | 2767 | { |
8fb9f6fe | 2768 | /* Give up if the expression is larger than the MAX that we allow. */ |
2769 | if (size_expr++ > PARAM_VALUE (PARAM_SCEV_MAX_EXPR_SIZE)) | |
2770 | return chrec_dont_know; | |
2771 | ||
8491bc74 | 2772 | if (chrec == NULL_TREE |
2773 | || automatically_generated_chrec_p (chrec) | |
903dae48 | 2774 | || is_gimple_min_invariant (chrec)) |
c2c3fd24 | 2775 | return chrec; |
2776 | ||
2777 | switch (TREE_CODE (chrec)) | |
2778 | { | |
2779 | case SSA_NAME: | |
6ee802ad | 2780 | return instantiate_scev_name (instantiate_below, evolution_loop, |
2781 | inner_loop, chrec, | |
32e31826 | 2782 | fold_conversions, size_expr); |
c2c3fd24 | 2783 | |
2784 | case POLYNOMIAL_CHREC: | |
6ee802ad | 2785 | return instantiate_scev_poly (instantiate_below, evolution_loop, |
2786 | inner_loop, chrec, | |
32e31826 | 2787 | fold_conversions, size_expr); |
c2c3fd24 | 2788 | |
0de36bdb | 2789 | case POINTER_PLUS_EXPR: |
c2c3fd24 | 2790 | case PLUS_EXPR: |
c2c3fd24 | 2791 | case MINUS_EXPR: |
c2c3fd24 | 2792 | case MULT_EXPR: |
6ee802ad | 2793 | return instantiate_scev_binary (instantiate_below, evolution_loop, |
2794 | inner_loop, chrec, | |
9e9aa0c6 | 2795 | TREE_CODE (chrec), chrec_type (chrec), |
2796 | TREE_OPERAND (chrec, 0), | |
2797 | TREE_OPERAND (chrec, 1), | |
32e31826 | 2798 | fold_conversions, size_expr); |
c2c3fd24 | 2799 | |
72dd6141 | 2800 | CASE_CONVERT: |
6ee802ad | 2801 | return instantiate_scev_convert (instantiate_below, evolution_loop, |
2802 | inner_loop, chrec, | |
7723692a | 2803 | TREE_TYPE (chrec), TREE_OPERAND (chrec, 0), |
32e31826 | 2804 | fold_conversions, size_expr); |
c2c3fd24 | 2805 | |
9d206f16 | 2806 | case NEGATE_EXPR: |
b6eab06c | 2807 | case BIT_NOT_EXPR: |
6ee802ad | 2808 | return instantiate_scev_not (instantiate_below, evolution_loop, |
2809 | inner_loop, chrec, | |
c43f1e90 | 2810 | TREE_CODE (chrec), TREE_TYPE (chrec), |
2811 | TREE_OPERAND (chrec, 0), | |
32e31826 | 2812 | fold_conversions, size_expr); |
b6eab06c | 2813 | |
0d0cdcaa | 2814 | case ADDR_EXPR: |
c2c3fd24 | 2815 | case SCEV_NOT_KNOWN: |
2816 | return chrec_dont_know; | |
2817 | ||
2818 | case SCEV_KNOWN: | |
2819 | return chrec_known; | |
5a10dfba | 2820 | |
3e0b5bba | 2821 | case ARRAY_REF: |
6ee802ad | 2822 | return instantiate_array_ref (instantiate_below, evolution_loop, |
2823 | inner_loop, chrec, | |
32e31826 | 2824 | fold_conversions, size_expr); |
3e0b5bba | 2825 | |
c2c3fd24 | 2826 | default: |
2827 | break; | |
2828 | } | |
2829 | ||
8e34a7c6 | 2830 | if (VL_EXP_CLASS_P (chrec)) |
2831 | return chrec_dont_know; | |
2832 | ||
c2c3fd24 | 2833 | switch (TREE_CODE_LENGTH (TREE_CODE (chrec))) |
2834 | { | |
2835 | case 3: | |
6ee802ad | 2836 | return instantiate_scev_3 (instantiate_below, evolution_loop, |
2837 | inner_loop, chrec, | |
32e31826 | 2838 | fold_conversions, size_expr); |
c2c3fd24 | 2839 | |
2840 | case 2: | |
6ee802ad | 2841 | return instantiate_scev_2 (instantiate_below, evolution_loop, |
2842 | inner_loop, chrec, | |
32e31826 | 2843 | fold_conversions, size_expr); |
39251a91 | 2844 | |
c2c3fd24 | 2845 | case 1: |
6ee802ad | 2846 | return instantiate_scev_1 (instantiate_below, evolution_loop, |
2847 | inner_loop, chrec, | |
32e31826 | 2848 | fold_conversions, size_expr); |
c2c3fd24 | 2849 | |
2850 | case 0: | |
2851 | return chrec; | |
2852 | ||
2853 | default: | |
2854 | break; | |
2855 | } | |
2856 | ||
2857 | /* Too complicated to handle. */ | |
2858 | return chrec_dont_know; | |
2859 | } | |
b9d73ea6 | 2860 | |
2861 | /* Analyze all the parameters of the chrec that were left under a | |
089aa668 | 2862 | symbolic form. INSTANTIATE_BELOW is the basic block that stops the |
2863 | recursive instantiation of parameters: a parameter is a variable | |
2864 | that is defined in a basic block that dominates INSTANTIATE_BELOW or | |
2865 | a function parameter. */ | |
b9d73ea6 | 2866 | |
2867 | tree | |
089aa668 | 2868 | instantiate_scev (basic_block instantiate_below, struct loop *evolution_loop, |
afd80ffb | 2869 | tree chrec) |
b9d73ea6 | 2870 | { |
c2c3fd24 | 2871 | tree res; |
2872 | ||
487a9bc1 | 2873 | if (dump_file && (dump_flags & TDF_SCEV)) |
c2c3fd24 | 2874 | { |
afd80ffb | 2875 | fprintf (dump_file, "(instantiate_scev \n"); |
089aa668 | 2876 | fprintf (dump_file, " (instantiate_below = %d)\n", instantiate_below->index); |
afd80ffb | 2877 | fprintf (dump_file, " (evolution_loop = %d)\n", evolution_loop->num); |
c2c3fd24 | 2878 | fprintf (dump_file, " (chrec = "); |
2879 | print_generic_expr (dump_file, chrec, 0); | |
2880 | fprintf (dump_file, ")\n"); | |
2881 | } | |
48e1416a | 2882 | |
32e31826 | 2883 | bool destr = false; |
2884 | if (!global_cache) | |
2885 | { | |
2886 | global_cache = new instantiate_cache_type; | |
2887 | destr = true; | |
2888 | } | |
2889 | ||
6ee802ad | 2890 | res = instantiate_scev_r (instantiate_below, evolution_loop, |
32e31826 | 2891 | NULL, chrec, false, 0); |
2892 | ||
2893 | if (destr) | |
2894 | { | |
2895 | delete global_cache; | |
2896 | global_cache = NULL; | |
2897 | } | |
c2c3fd24 | 2898 | |
487a9bc1 | 2899 | if (dump_file && (dump_flags & TDF_SCEV)) |
c2c3fd24 | 2900 | { |
2901 | fprintf (dump_file, " (res = "); | |
2902 | print_generic_expr (dump_file, res, 0); | |
2903 | fprintf (dump_file, "))\n"); | |
2904 | } | |
15a951ca | 2905 | |
c2c3fd24 | 2906 | return res; |
2907 | } | |
2908 | ||
2909 | /* Similar to instantiate_parameters, but does not introduce the | |
88d02c9e | 2910 | evolutions in outer loops for LOOP invariants in CHREC, and does not |
2911 | care about causing overflows, as long as they do not affect value | |
2912 | of an expression. */ | |
c2c3fd24 | 2913 | |
80bb306a | 2914 | tree |
c2c3fd24 | 2915 | resolve_mixers (struct loop *loop, tree chrec) |
2916 | { | |
32e31826 | 2917 | bool destr = false; |
2918 | if (!global_cache) | |
2919 | { | |
2920 | global_cache = new instantiate_cache_type; | |
2921 | destr = true; | |
2922 | } | |
2923 | ||
6ee802ad | 2924 | tree ret = instantiate_scev_r (block_before_loop (loop), loop, NULL, |
32e31826 | 2925 | chrec, true, 0); |
2926 | ||
2927 | if (destr) | |
2928 | { | |
2929 | delete global_cache; | |
2930 | global_cache = NULL; | |
2931 | } | |
2932 | ||
15a951ca | 2933 | return ret; |
c2c3fd24 | 2934 | } |
2935 | ||
48e1416a | 2936 | /* Entry point for the analysis of the number of iterations pass. |
c2c3fd24 | 2937 | This function tries to safely approximate the number of iterations |
2938 | the loop will run. When this property is not decidable at compile | |
134c053e | 2939 | time, the result is chrec_dont_know. Otherwise the result is a |
2940 | scalar or a symbolic parameter. When the number of iterations may | |
2941 | be equal to zero and the property cannot be determined at compile | |
2942 | time, the result is a COND_EXPR that represents in a symbolic form | |
2943 | the conditions under which the number of iterations is not zero. | |
48e1416a | 2944 | |
c2c3fd24 | 2945 | Example of analysis: suppose that the loop has an exit condition: |
48e1416a | 2946 | |
c2c3fd24 | 2947 | "if (b > 49) goto end_loop;" |
48e1416a | 2948 | |
c2c3fd24 | 2949 | and that in a previous analysis we have determined that the |
2950 | variable 'b' has an evolution function: | |
48e1416a | 2951 | |
2952 | "EF = {23, +, 5}_2". | |
2953 | ||
c2c3fd24 | 2954 | When we evaluate the function at the point 5, i.e. the value of the |
2955 | variable 'b' after 5 iterations in the loop, we have EF (5) = 48, | |
2956 | and EF (6) = 53. In this case the value of 'b' on exit is '53' and | |
2957 | the loop body has been executed 6 times. */ | |
2958 | ||
48e1416a | 2959 | tree |
0c3c2e56 | 2960 | number_of_latch_executions (struct loop *loop) |
c2c3fd24 | 2961 | { |
c2c3fd24 | 2962 | edge exit; |
2963 | struct tree_niter_desc niter_desc; | |
134c053e | 2964 | tree may_be_zero; |
2965 | tree res; | |
c2c3fd24 | 2966 | |
134c053e | 2967 | /* Determine whether the number of iterations in loop has already |
c2c3fd24 | 2968 | been computed. */ |
2969 | res = loop->nb_iterations; | |
2970 | if (res) | |
2971 | return res; | |
134c053e | 2972 | |
2973 | may_be_zero = NULL_TREE; | |
c2c3fd24 | 2974 | |
487a9bc1 | 2975 | if (dump_file && (dump_flags & TDF_SCEV)) |
134c053e | 2976 | fprintf (dump_file, "(number_of_iterations_in_loop = \n"); |
48e1416a | 2977 | |
134c053e | 2978 | res = chrec_dont_know; |
d9e7e1a2 | 2979 | exit = single_exit (loop); |
c2c3fd24 | 2980 | |
134c053e | 2981 | if (exit && number_of_iterations_exit (loop, exit, &niter_desc, false)) |
2982 | { | |
2983 | may_be_zero = niter_desc.may_be_zero; | |
2984 | res = niter_desc.niter; | |
2985 | } | |
2986 | ||
2987 | if (res == chrec_dont_know | |
2988 | || !may_be_zero | |
2989 | || integer_zerop (may_be_zero)) | |
2990 | ; | |
2991 | else if (integer_nonzerop (may_be_zero)) | |
2992 | res = build_int_cst (TREE_TYPE (res), 0); | |
c2c3fd24 | 2993 | |
134c053e | 2994 | else if (COMPARISON_CLASS_P (may_be_zero)) |
2995 | res = fold_build3 (COND_EXPR, TREE_TYPE (res), may_be_zero, | |
2996 | build_int_cst (TREE_TYPE (res), 0), res); | |
c2c3fd24 | 2997 | else |
2998 | res = chrec_dont_know; | |
2999 | ||
487a9bc1 | 3000 | if (dump_file && (dump_flags & TDF_SCEV)) |
134c053e | 3001 | { |
3002 | fprintf (dump_file, " (set_nb_iterations_in_loop = "); | |
3003 | print_generic_expr (dump_file, res, 0); | |
3004 | fprintf (dump_file, "))\n"); | |
3005 | } | |
3006 | ||
3007 | loop->nb_iterations = res; | |
3008 | return res; | |
c2c3fd24 | 3009 | } |
c2c3fd24 | 3010 | \f |
3011 | ||
3012 | /* Counters for the stats. */ | |
3013 | ||
48e1416a | 3014 | struct chrec_stats |
c2c3fd24 | 3015 | { |
3016 | unsigned nb_chrecs; | |
3017 | unsigned nb_affine; | |
3018 | unsigned nb_affine_multivar; | |
3019 | unsigned nb_higher_poly; | |
3020 | unsigned nb_chrec_dont_know; | |
3021 | unsigned nb_undetermined; | |
3022 | }; | |
3023 | ||
3024 | /* Reset the counters. */ | |
3025 | ||
3026 | static inline void | |
3027 | reset_chrecs_counters (struct chrec_stats *stats) | |
3028 | { | |
3029 | stats->nb_chrecs = 0; | |
3030 | stats->nb_affine = 0; | |
3031 | stats->nb_affine_multivar = 0; | |
3032 | stats->nb_higher_poly = 0; | |
3033 | stats->nb_chrec_dont_know = 0; | |
3034 | stats->nb_undetermined = 0; | |
3035 | } | |
3036 | ||
3037 | /* Dump the contents of a CHREC_STATS structure. */ | |
3038 | ||
3039 | static void | |
3040 | dump_chrecs_stats (FILE *file, struct chrec_stats *stats) | |
3041 | { | |
3042 | fprintf (file, "\n(\n"); | |
3043 | fprintf (file, "-----------------------------------------\n"); | |
3044 | fprintf (file, "%d\taffine univariate chrecs\n", stats->nb_affine); | |
3045 | fprintf (file, "%d\taffine multivariate chrecs\n", stats->nb_affine_multivar); | |
48e1416a | 3046 | fprintf (file, "%d\tdegree greater than 2 polynomials\n", |
c2c3fd24 | 3047 | stats->nb_higher_poly); |
3048 | fprintf (file, "%d\tchrec_dont_know chrecs\n", stats->nb_chrec_dont_know); | |
3049 | fprintf (file, "-----------------------------------------\n"); | |
3050 | fprintf (file, "%d\ttotal chrecs\n", stats->nb_chrecs); | |
48e1416a | 3051 | fprintf (file, "%d\twith undetermined coefficients\n", |
c2c3fd24 | 3052 | stats->nb_undetermined); |
3053 | fprintf (file, "-----------------------------------------\n"); | |
48e1416a | 3054 | fprintf (file, "%d\tchrecs in the scev database\n", |
c2c3fd24 | 3055 | (int) htab_elements (scalar_evolution_info)); |
3056 | fprintf (file, "%d\tsets in the scev database\n", nb_set_scev); | |
3057 | fprintf (file, "%d\tgets in the scev database\n", nb_get_scev); | |
3058 | fprintf (file, "-----------------------------------------\n"); | |
3059 | fprintf (file, ")\n\n"); | |
3060 | } | |
3061 | ||
3062 | /* Gather statistics about CHREC. */ | |
3063 | ||
3064 | static void | |
3065 | gather_chrec_stats (tree chrec, struct chrec_stats *stats) | |
3066 | { | |
3067 | if (dump_file && (dump_flags & TDF_STATS)) | |
3068 | { | |
3069 | fprintf (dump_file, "(classify_chrec "); | |
3070 | print_generic_expr (dump_file, chrec, 0); | |
3071 | fprintf (dump_file, "\n"); | |
3072 | } | |
48e1416a | 3073 | |
c2c3fd24 | 3074 | stats->nb_chrecs++; |
48e1416a | 3075 | |
c2c3fd24 | 3076 | if (chrec == NULL_TREE) |
3077 | { | |
3078 | stats->nb_undetermined++; | |
3079 | return; | |
3080 | } | |
48e1416a | 3081 | |
c2c3fd24 | 3082 | switch (TREE_CODE (chrec)) |
3083 | { | |
3084 | case POLYNOMIAL_CHREC: | |
3085 | if (evolution_function_is_affine_p (chrec)) | |
3086 | { | |
3087 | if (dump_file && (dump_flags & TDF_STATS)) | |
3088 | fprintf (dump_file, " affine_univariate\n"); | |
3089 | stats->nb_affine++; | |
3090 | } | |
9c77efff | 3091 | else if (evolution_function_is_affine_multivariate_p (chrec, 0)) |
c2c3fd24 | 3092 | { |
3093 | if (dump_file && (dump_flags & TDF_STATS)) | |
3094 | fprintf (dump_file, " affine_multivariate\n"); | |
3095 | stats->nb_affine_multivar++; | |
3096 | } | |
3097 | else | |
3098 | { | |
3099 | if (dump_file && (dump_flags & TDF_STATS)) | |
3100 | fprintf (dump_file, " higher_degree_polynomial\n"); | |
3101 | stats->nb_higher_poly++; | |
3102 | } | |
48e1416a | 3103 | |
c2c3fd24 | 3104 | break; |
3105 | ||
3106 | default: | |
3107 | break; | |
3108 | } | |
48e1416a | 3109 | |
c2c3fd24 | 3110 | if (chrec_contains_undetermined (chrec)) |
3111 | { | |
3112 | if (dump_file && (dump_flags & TDF_STATS)) | |
3113 | fprintf (dump_file, " undetermined\n"); | |
3114 | stats->nb_undetermined++; | |
3115 | } | |
48e1416a | 3116 | |
c2c3fd24 | 3117 | if (dump_file && (dump_flags & TDF_STATS)) |
3118 | fprintf (dump_file, ")\n"); | |
3119 | } | |
3120 | ||
c2c3fd24 | 3121 | /* Callback for htab_traverse, gathers information on chrecs in the |
3122 | hashtable. */ | |
3123 | ||
3124 | static int | |
3125 | gather_stats_on_scev_database_1 (void **slot, void *stats) | |
3126 | { | |
a9c6c0e3 | 3127 | struct scev_info_str *entry = (struct scev_info_str *) *slot; |
c2c3fd24 | 3128 | |
a9c6c0e3 | 3129 | gather_chrec_stats (entry->chrec, (struct chrec_stats *) stats); |
c2c3fd24 | 3130 | |
3131 | return 1; | |
3132 | } | |
3133 | ||
3134 | /* Classify the chrecs of the whole database. */ | |
3135 | ||
48e1416a | 3136 | void |
c2c3fd24 | 3137 | gather_stats_on_scev_database (void) |
3138 | { | |
3139 | struct chrec_stats stats; | |
48e1416a | 3140 | |
c2c3fd24 | 3141 | if (!dump_file) |
3142 | return; | |
48e1416a | 3143 | |
c2c3fd24 | 3144 | reset_chrecs_counters (&stats); |
48e1416a | 3145 | |
c2c3fd24 | 3146 | htab_traverse (scalar_evolution_info, gather_stats_on_scev_database_1, |
3147 | &stats); | |
3148 | ||
3149 | dump_chrecs_stats (dump_file, &stats); | |
3150 | } | |
3151 | ||
3152 | \f | |
3153 | ||
3154 | /* Initializer. */ | |
3155 | ||
3156 | static void | |
3157 | initialize_scalar_evolutions_analyzer (void) | |
3158 | { | |
3159 | /* The elements below are unique. */ | |
3160 | if (chrec_dont_know == NULL_TREE) | |
3161 | { | |
3162 | chrec_not_analyzed_yet = NULL_TREE; | |
3163 | chrec_dont_know = make_node (SCEV_NOT_KNOWN); | |
3164 | chrec_known = make_node (SCEV_KNOWN); | |
f3830c7c | 3165 | TREE_TYPE (chrec_dont_know) = void_type_node; |
3166 | TREE_TYPE (chrec_known) = void_type_node; | |
c2c3fd24 | 3167 | } |
3168 | } | |
3169 | ||
3170 | /* Initialize the analysis of scalar evolutions for LOOPS. */ | |
3171 | ||
3172 | void | |
7194de72 | 3173 | scev_initialize (void) |
c2c3fd24 | 3174 | { |
17519ba0 | 3175 | struct loop *loop; |
c2c3fd24 | 3176 | |
ba72912a | 3177 | scalar_evolution_info = htab_create_ggc (100, hash_scev_info, eq_scev_info, |
3178 | del_scev_info); | |
48e1416a | 3179 | |
c2c3fd24 | 3180 | initialize_scalar_evolutions_analyzer (); |
3181 | ||
f21d4d00 | 3182 | FOR_EACH_LOOP (loop, 0) |
17519ba0 | 3183 | { |
3184 | loop->nb_iterations = NULL_TREE; | |
3185 | } | |
c2c3fd24 | 3186 | } |
3187 | ||
a9ef9877 | 3188 | /* Return true if SCEV is initialized. */ |
3189 | ||
3190 | bool | |
3191 | scev_initialized_p (void) | |
3192 | { | |
3193 | return scalar_evolution_info != NULL; | |
3194 | } | |
3195 | ||
efe339e3 | 3196 | /* Cleans up the information cached by the scalar evolutions analysis |
3197 | in the hash table. */ | |
3198 | ||
3199 | void | |
3200 | scev_reset_htab (void) | |
3201 | { | |
3202 | if (!scalar_evolution_info) | |
3203 | return; | |
3204 | ||
3205 | htab_empty (scalar_evolution_info); | |
3206 | } | |
3207 | ||
3208 | /* Cleans up the information cached by the scalar evolutions analysis | |
3209 | in the hash table and in the loop->nb_iterations. */ | |
c2c3fd24 | 3210 | |
3211 | void | |
3212 | scev_reset (void) | |
3213 | { | |
c2c3fd24 | 3214 | struct loop *loop; |
3215 | ||
efe339e3 | 3216 | scev_reset_htab (); |
3217 | ||
f21d4d00 | 3218 | FOR_EACH_LOOP (loop, 0) |
c2c3fd24 | 3219 | { |
17519ba0 | 3220 | loop->nb_iterations = NULL_TREE; |
c2c3fd24 | 3221 | } |
b9d73ea6 | 3222 | } |
3223 | ||
76610704 | 3224 | /* Checks whether use of OP in USE_LOOP behaves as a simple affine iv with |
3225 | respect to WRTO_LOOP and returns its base and step in IV if possible | |
3226 | (see analyze_scalar_evolution_in_loop for more details on USE_LOOP | |
3227 | and WRTO_LOOP). If ALLOW_NONCONSTANT_STEP is true, we want step to be | |
3228 | invariant in LOOP. Otherwise we require it to be an integer constant. | |
48e1416a | 3229 | |
76610704 | 3230 | IV->no_overflow is set to true if we are sure the iv cannot overflow (e.g. |
3231 | because it is computed in signed arithmetics). Consequently, adding an | |
3232 | induction variable | |
48e1416a | 3233 | |
76610704 | 3234 | for (i = IV->base; ; i += IV->step) |
3235 | ||
3236 | is only safe if IV->no_overflow is false, or TYPE_OVERFLOW_UNDEFINED is | |
3237 | false for the type of the induction variable, or you can prove that i does | |
3238 | not wrap by some other argument. Otherwise, this might introduce undefined | |
3239 | behavior, and | |
48e1416a | 3240 | |
76610704 | 3241 | for (i = iv->base; ; i = (type) ((unsigned type) i + (unsigned type) iv->step)) |
3242 | ||
3243 | must be used instead. */ | |
b9d73ea6 | 3244 | |
3245 | bool | |
76610704 | 3246 | simple_iv (struct loop *wrto_loop, struct loop *use_loop, tree op, |
3247 | affine_iv *iv, bool allow_nonconstant_step) | |
b9d73ea6 | 3248 | { |
c2c3fd24 | 3249 | tree type, ev; |
553b9523 | 3250 | bool folded_casts; |
c2c3fd24 | 3251 | |
553b9523 | 3252 | iv->base = NULL_TREE; |
3253 | iv->step = NULL_TREE; | |
3254 | iv->no_overflow = false; | |
c2c3fd24 | 3255 | |
3256 | type = TREE_TYPE (op); | |
367113ea | 3257 | if (!POINTER_TYPE_P (type) |
3258 | && !INTEGRAL_TYPE_P (type)) | |
c2c3fd24 | 3259 | return false; |
3260 | ||
76610704 | 3261 | ev = analyze_scalar_evolution_in_loop (wrto_loop, use_loop, op, |
553b9523 | 3262 | &folded_casts); |
76610704 | 3263 | if (chrec_contains_undetermined (ev) |
3264 | || chrec_contains_symbols_defined_in_loop (ev, wrto_loop->num)) | |
c2c3fd24 | 3265 | return false; |
3266 | ||
76610704 | 3267 | if (tree_does_not_contain_chrecs (ev)) |
c2c3fd24 | 3268 | { |
553b9523 | 3269 | iv->base = ev; |
7a973feb | 3270 | iv->step = build_int_cst (TREE_TYPE (ev), 0); |
553b9523 | 3271 | iv->no_overflow = true; |
c2c3fd24 | 3272 | return true; |
3273 | } | |
3274 | ||
3275 | if (TREE_CODE (ev) != POLYNOMIAL_CHREC | |
76610704 | 3276 | || CHREC_VARIABLE (ev) != (unsigned) wrto_loop->num) |
c2c3fd24 | 3277 | return false; |
3278 | ||
553b9523 | 3279 | iv->step = CHREC_RIGHT (ev); |
76610704 | 3280 | if ((!allow_nonconstant_step && TREE_CODE (iv->step) != INTEGER_CST) |
3281 | || tree_contains_chrecs (iv->step, NULL)) | |
c2c3fd24 | 3282 | return false; |
651874e1 | 3283 | |
553b9523 | 3284 | iv->base = CHREC_LEFT (ev); |
76610704 | 3285 | if (tree_contains_chrecs (iv->base, NULL)) |
c2c3fd24 | 3286 | return false; |
3287 | ||
981eb798 | 3288 | iv->no_overflow = !folded_casts && TYPE_OVERFLOW_UNDEFINED (type); |
3289 | ||
c2c3fd24 | 3290 | return true; |
3291 | } | |
3292 | ||
c2c3fd24 | 3293 | /* Finalize the scalar evolution analysis. */ |
3294 | ||
3295 | void | |
3296 | scev_finalize (void) | |
3297 | { | |
7a3bf727 | 3298 | if (!scalar_evolution_info) |
3299 | return; | |
c2c3fd24 | 3300 | htab_delete (scalar_evolution_info); |
d8a0d6b8 | 3301 | scalar_evolution_info = NULL; |
c2c3fd24 | 3302 | } |
3303 | ||
590f8b68 | 3304 | /* Returns true if the expression EXPR is considered to be too expensive |
3305 | for scev_const_prop. */ | |
3306 | ||
3307 | bool | |
3308 | expression_expensive_p (tree expr) | |
3309 | { | |
3310 | enum tree_code code; | |
3311 | ||
3312 | if (is_gimple_val (expr)) | |
3313 | return false; | |
3314 | ||
3315 | code = TREE_CODE (expr); | |
3316 | if (code == TRUNC_DIV_EXPR | |
3317 | || code == CEIL_DIV_EXPR | |
3318 | || code == FLOOR_DIV_EXPR | |
3319 | || code == ROUND_DIV_EXPR | |
3320 | || code == TRUNC_MOD_EXPR | |
3321 | || code == CEIL_MOD_EXPR | |
3322 | || code == FLOOR_MOD_EXPR | |
3323 | || code == ROUND_MOD_EXPR | |
3324 | || code == EXACT_DIV_EXPR) | |
3325 | { | |
3326 | /* Division by power of two is usually cheap, so we allow it. | |
3327 | Forbid anything else. */ | |
3328 | if (!integer_pow2p (TREE_OPERAND (expr, 1))) | |
3329 | return true; | |
3330 | } | |
3331 | ||
3332 | switch (TREE_CODE_CLASS (code)) | |
3333 | { | |
3334 | case tcc_binary: | |
3335 | case tcc_comparison: | |
3336 | if (expression_expensive_p (TREE_OPERAND (expr, 1))) | |
3337 | return true; | |
3338 | ||
3339 | /* Fallthru. */ | |
3340 | case tcc_unary: | |
3341 | return expression_expensive_p (TREE_OPERAND (expr, 0)); | |
3342 | ||
3343 | default: | |
3344 | return true; | |
3345 | } | |
3346 | } | |
3347 | ||
10fec820 | 3348 | /* Replace ssa names for that scev can prove they are constant by the |
f4d7629d | 3349 | appropriate constants. Also perform final value replacement in loops, |
3350 | in case the replacement expressions are cheap. | |
48e1416a | 3351 | |
10fec820 | 3352 | We only consider SSA names defined by phi nodes; rest is left to the |
3353 | ordinary constant propagation pass. */ | |
3354 | ||
2a1990e9 | 3355 | unsigned int |
10fec820 | 3356 | scev_const_prop (void) |
3357 | { | |
3358 | basic_block bb; | |
75a70cf9 | 3359 | tree name, type, ev; |
1a91d914 | 3360 | gphi *phi; |
3361 | gassign *ass; | |
f4d7629d | 3362 | struct loop *loop, *ex_loop; |
10fec820 | 3363 | bitmap ssa_names_to_remove = NULL; |
f4d7629d | 3364 | unsigned i; |
1a91d914 | 3365 | gphi_iterator psi; |
10fec820 | 3366 | |
41f75a99 | 3367 | if (number_of_loops (cfun) <= 1) |
2a1990e9 | 3368 | return 0; |
10fec820 | 3369 | |
fc00614f | 3370 | FOR_EACH_BB_FN (bb, cfun) |
10fec820 | 3371 | { |
3372 | loop = bb->loop_father; | |
3373 | ||
75a70cf9 | 3374 | for (psi = gsi_start_phis (bb); !gsi_end_p (psi); gsi_next (&psi)) |
10fec820 | 3375 | { |
1a91d914 | 3376 | phi = psi.phi (); |
10fec820 | 3377 | name = PHI_RESULT (phi); |
3378 | ||
7c782c9b | 3379 | if (virtual_operand_p (name)) |
10fec820 | 3380 | continue; |
3381 | ||
3382 | type = TREE_TYPE (name); | |
3383 | ||
3384 | if (!POINTER_TYPE_P (type) | |
3385 | && !INTEGRAL_TYPE_P (type)) | |
3386 | continue; | |
3387 | ||
3388 | ev = resolve_mixers (loop, analyze_scalar_evolution (loop, name)); | |
3389 | if (!is_gimple_min_invariant (ev) | |
3390 | || !may_propagate_copy (name, ev)) | |
3391 | continue; | |
3392 | ||
3393 | /* Replace the uses of the name. */ | |
9887dd18 | 3394 | if (name != ev) |
3395 | replace_uses_by (name, ev); | |
10fec820 | 3396 | |
3397 | if (!ssa_names_to_remove) | |
3398 | ssa_names_to_remove = BITMAP_ALLOC (NULL); | |
3399 | bitmap_set_bit (ssa_names_to_remove, SSA_NAME_VERSION (name)); | |
3400 | } | |
3401 | } | |
3402 | ||
17889f9d | 3403 | /* Remove the ssa names that were replaced by constants. We do not |
3404 | remove them directly in the previous cycle, since this | |
3405 | invalidates scev cache. */ | |
10fec820 | 3406 | if (ssa_names_to_remove) |
3407 | { | |
3408 | bitmap_iterator bi; | |
10fec820 | 3409 | |
3410 | EXECUTE_IF_SET_IN_BITMAP (ssa_names_to_remove, 0, i, bi) | |
3411 | { | |
75a70cf9 | 3412 | gimple_stmt_iterator psi; |
10fec820 | 3413 | name = ssa_name (i); |
1a91d914 | 3414 | phi = as_a <gphi *> (SSA_NAME_DEF_STMT (name)); |
10fec820 | 3415 | |
75a70cf9 | 3416 | gcc_assert (gimple_code (phi) == GIMPLE_PHI); |
3417 | psi = gsi_for_stmt (phi); | |
3418 | remove_phi_node (&psi, true); | |
10fec820 | 3419 | } |
3420 | ||
3421 | BITMAP_FREE (ssa_names_to_remove); | |
3422 | scev_reset (); | |
3423 | } | |
f4d7629d | 3424 | |
3425 | /* Now the regular final value replacement. */ | |
f21d4d00 | 3426 | FOR_EACH_LOOP (loop, LI_FROM_INNERMOST) |
f4d7629d | 3427 | { |
3428 | edge exit; | |
75a70cf9 | 3429 | tree def, rslt, niter; |
f6a34e3f | 3430 | gimple_stmt_iterator gsi; |
f4d7629d | 3431 | |
f4d7629d | 3432 | /* If we do not know exact number of iterations of the loop, we cannot |
3433 | replace the final value. */ | |
d9e7e1a2 | 3434 | exit = single_exit (loop); |
553b9523 | 3435 | if (!exit) |
3436 | continue; | |
3437 | ||
0c3c2e56 | 3438 | niter = number_of_latch_executions (loop); |
a463eaea | 3439 | if (niter == chrec_dont_know) |
f4d7629d | 3440 | continue; |
5bacce6b | 3441 | |
3442 | /* Ensure that it is possible to insert new statements somewhere. */ | |
3443 | if (!single_pred_p (exit->dest)) | |
3444 | split_loop_exit_edge (exit); | |
f6a34e3f | 3445 | gsi = gsi_after_labels (exit->dest); |
5bacce6b | 3446 | |
9e3536f4 | 3447 | ex_loop = superloop_at_depth (loop, |
3448 | loop_depth (exit->dest->loop_father) + 1); | |
f4d7629d | 3449 | |
75a70cf9 | 3450 | for (psi = gsi_start_phis (exit->dest); !gsi_end_p (psi); ) |
f4d7629d | 3451 | { |
1a91d914 | 3452 | phi = psi.phi (); |
5bacce6b | 3453 | rslt = PHI_RESULT (phi); |
f4d7629d | 3454 | def = PHI_ARG_DEF_FROM_EDGE (phi, exit); |
7c782c9b | 3455 | if (virtual_operand_p (def)) |
75a70cf9 | 3456 | { |
3457 | gsi_next (&psi); | |
3458 | continue; | |
3459 | } | |
f4d7629d | 3460 | |
3461 | if (!POINTER_TYPE_P (TREE_TYPE (def)) | |
3462 | && !INTEGRAL_TYPE_P (TREE_TYPE (def))) | |
75a70cf9 | 3463 | { |
3464 | gsi_next (&psi); | |
3465 | continue; | |
3466 | } | |
f4d7629d | 3467 | |
f6a34e3f | 3468 | bool folded_casts; |
3469 | def = analyze_scalar_evolution_in_loop (ex_loop, loop, def, | |
3470 | &folded_casts); | |
5bacce6b | 3471 | def = compute_overall_effect_of_inner_loop (ex_loop, def); |
f4d7629d | 3472 | if (!tree_does_not_contain_chrecs (def) |
72079d62 | 3473 | || chrec_contains_symbols_defined_in_loop (def, ex_loop->num) |
3474 | /* Moving the computation from the loop may prolong life range | |
3475 | of some ssa names, which may cause problems if they appear | |
3476 | on abnormal edges. */ | |
590f8b68 | 3477 | || contains_abnormal_ssa_name_p (def) |
3478 | /* Do not emit expensive expressions. The rationale is that | |
3479 | when someone writes a code like | |
3480 | ||
3481 | while (n > 45) n -= 45; | |
3482 | ||
3483 | he probably knows that n is not large, and does not want it | |
3484 | to be turned into n %= 45. */ | |
3485 | || expression_expensive_p (def)) | |
75a70cf9 | 3486 | { |
d70b7140 | 3487 | if (dump_file && (dump_flags & TDF_DETAILS)) |
3488 | { | |
3489 | fprintf (dump_file, "not replacing:\n "); | |
3490 | print_gimple_stmt (dump_file, phi, 0, 0); | |
3491 | fprintf (dump_file, "\n"); | |
3492 | } | |
75a70cf9 | 3493 | gsi_next (&psi); |
3494 | continue; | |
3495 | } | |
f4d7629d | 3496 | |
17889f9d | 3497 | /* Eliminate the PHI node and replace it by a computation outside |
5bacce6b | 3498 | the loop. */ |
d70b7140 | 3499 | if (dump_file) |
3500 | { | |
3501 | fprintf (dump_file, "\nfinal value replacement:\n "); | |
3502 | print_gimple_stmt (dump_file, phi, 0, 0); | |
3503 | fprintf (dump_file, " with\n "); | |
3504 | } | |
5bacce6b | 3505 | def = unshare_expr (def); |
75a70cf9 | 3506 | remove_phi_node (&psi, false); |
3507 | ||
f6a34e3f | 3508 | /* If def's type has undefined overflow and there were folded |
3509 | casts, rewrite all stmts added for def into arithmetics | |
3510 | with defined overflow behavior. */ | |
3511 | if (folded_casts && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (def))) | |
3512 | { | |
3513 | gimple_seq stmts; | |
3514 | gimple_stmt_iterator gsi2; | |
3515 | def = force_gimple_operand (def, &stmts, true, NULL_TREE); | |
3516 | gsi2 = gsi_start (stmts); | |
3517 | while (!gsi_end_p (gsi2)) | |
3518 | { | |
3519 | gimple stmt = gsi_stmt (gsi2); | |
3520 | gimple_stmt_iterator gsi3 = gsi2; | |
3521 | gsi_next (&gsi2); | |
3522 | gsi_remove (&gsi3, false); | |
3523 | if (is_gimple_assign (stmt) | |
3524 | && arith_code_with_undefined_signed_overflow | |
3525 | (gimple_assign_rhs_code (stmt))) | |
3526 | gsi_insert_seq_before (&gsi, | |
3527 | rewrite_to_defined_overflow (stmt), | |
3528 | GSI_SAME_STMT); | |
3529 | else | |
3530 | gsi_insert_before (&gsi, stmt, GSI_SAME_STMT); | |
3531 | } | |
3532 | } | |
3533 | else | |
3534 | def = force_gimple_operand_gsi (&gsi, def, false, NULL_TREE, | |
3535 | true, GSI_SAME_STMT); | |
3536 | ||
75a70cf9 | 3537 | ass = gimple_build_assign (rslt, def); |
f6a34e3f | 3538 | gsi_insert_before (&gsi, ass, GSI_SAME_STMT); |
d70b7140 | 3539 | if (dump_file) |
3540 | { | |
3541 | print_gimple_stmt (dump_file, ass, 0, 0); | |
3542 | fprintf (dump_file, "\n"); | |
3543 | } | |
f4d7629d | 3544 | } |
3545 | } | |
2a1990e9 | 3546 | return 0; |
10fec820 | 3547 | } |
ccae4f9f | 3548 | |
3549 | #include "gt-tree-scalar-evolution.h" |