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e9eb809d | 1 | /* Scalar evolution detector. |
a5544970 | 2 | Copyright (C) 2003-2019 Free Software Foundation, Inc. |
e9eb809d ZD |
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 | |
9dcd6f09 | 9 | Software Foundation; either version 3, or (at your option) any later |
e9eb809d ZD |
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 | |
9dcd6f09 NC |
18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ | |
e9eb809d | 20 | |
b8698a0f L |
21 | /* |
22 | Description: | |
23 | ||
9baba81b SP |
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). | |
b8698a0f | 44 | |
9baba81b | 45 | A short sketch of the algorithm is: |
b8698a0f | 46 | |
9baba81b SP |
47 | Given a scalar variable to be analyzed, follow the SSA edge to |
48 | its definition: | |
b8698a0f | 49 | |
726a989a | 50 | - When the definition is a GIMPLE_ASSIGN: if the right hand side |
9baba81b | 51 | (RHS) of the definition cannot be statically analyzed, the answer |
b8698a0f | 52 | of the analyzer is: "don't know". |
9baba81b SP |
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: | |
b8698a0f | 74 | |
9baba81b | 75 | Example 1: Illustration of the basic algorithm. |
b8698a0f | 76 | |
9baba81b SP |
77 | | a = 3 |
78 | | loop_1 | |
79 | | b = phi (a, c) | |
80 | | c = b + 1 | |
81 | | if (c > 10) exit_loop | |
82 | | endloop | |
b8698a0f | 83 | |
9baba81b SP |
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 | |
3f227a8c | 104 | instantiate_parameters (loop_1, {a + 1, +, 1}_1), that gives after some |
9baba81b SP |
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: | |
b8698a0f | 114 | |
9baba81b SP |
115 | a -> 3 |
116 | b -> {3, +, 1}_1 | |
117 | c -> {4, +, 1}_1 | |
b8698a0f L |
118 | |
119 | or in terms of a C program: | |
120 | ||
9baba81b SP |
121 | | a = 3 |
122 | | for (x = 0; x <= 7; x++) | |
123 | | { | |
124 | | b = x + 3 | |
125 | | c = x + 4 | |
126 | | } | |
b8698a0f | 127 | |
3f227a8c | 128 | Example 2a: Illustration of the algorithm on nested loops. |
b8698a0f | 129 | |
9baba81b SP |
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 | |
b8698a0f | 138 | |
9baba81b SP |
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 | |
b8698a0f L |
141 | loop-phi-node, and its analysis as in Example 1, gives: |
142 | ||
9baba81b SP |
143 | b -> {c, +, 3}_2 |
144 | d -> {c + 3, +, 3}_2 | |
b8698a0f | 145 | |
9baba81b SP |
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 | |
b8698a0f L |
152 | equal to "+32", and the result is: |
153 | ||
9baba81b SP |
154 | a -> {1, +, 32}_1 |
155 | c -> {3, +, 32}_1 | |
3f227a8c JS |
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: | |
a213b219 SP |
177 | instantiate_scev (block_before_loop (loop_1), loop_3, "j + k"). |
178 | The result of this call is {{0, +, 1}_1, +, 1}_2. | |
3f227a8c | 179 | |
9baba81b | 180 | Example 3: Higher degree polynomials. |
b8698a0f | 181 | |
9baba81b SP |
182 | | loop_1 |
183 | | a = phi (2, b) | |
184 | | c = phi (5, d) | |
185 | | b = a + 1 | |
186 | | d = c + a | |
187 | | endloop | |
b8698a0f | 188 | |
9baba81b SP |
189 | a -> {2, +, 1}_1 |
190 | b -> {3, +, 1}_1 | |
191 | c -> {5, +, a}_1 | |
192 | d -> {5 + a, +, a}_1 | |
b8698a0f | 193 | |
3f227a8c JS |
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 | |
b8698a0f | 196 | |
9baba81b | 197 | Example 4: Lucas, Fibonacci, or mixers in general. |
b8698a0f | 198 | |
9baba81b SP |
199 | | loop_1 |
200 | | a = phi (1, b) | |
201 | | c = phi (3, d) | |
202 | | b = c | |
203 | | d = c + a | |
204 | | endloop | |
b8698a0f | 205 | |
9baba81b SP |
206 | a -> (1, c)_1 |
207 | c -> {3, +, a}_1 | |
b8698a0f | 208 | |
9baba81b SP |
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)". | |
b8698a0f | 214 | |
9baba81b SP |
215 | The symbolic chrec representation contains all the semantics of the |
216 | original code. What is more difficult is to use this information. | |
b8698a0f | 217 | |
9baba81b | 218 | Example 5: Flip-flops, or exchangers. |
b8698a0f | 219 | |
9baba81b SP |
220 | | loop_1 |
221 | | a = phi (1, b) | |
222 | | c = phi (3, d) | |
223 | | b = c | |
224 | | d = a | |
225 | | endloop | |
b8698a0f | 226 | |
9baba81b SP |
227 | a -> (1, c)_1 |
228 | c -> (3, a)_1 | |
b8698a0f | 229 | |
9baba81b | 230 | Based on these symbolic chrecs, it is possible to refine this |
b8698a0f L |
231 | information into the more precise PERIODIC_CHRECs: |
232 | ||
9baba81b SP |
233 | a -> |1, 3|_1 |
234 | c -> |3, 1|_1 | |
b8698a0f | 235 | |
9baba81b | 236 | This transformation is not yet implemented. |
b8698a0f | 237 | |
9baba81b | 238 | Further readings: |
b8698a0f | 239 | |
9baba81b SP |
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. | |
b8698a0f | 247 | |
9baba81b SP |
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 | ||
e9eb809d ZD |
256 | #include "config.h" |
257 | #include "system.h" | |
258 | #include "coretypes.h" | |
c7131fb2 | 259 | #include "backend.h" |
06a6b46a | 260 | #include "target.h" |
957060b5 | 261 | #include "rtl.h" |
06a6b46a | 262 | #include "optabs-query.h" |
cf2d1b38 | 263 | #include "tree.h" |
c7131fb2 | 264 | #include "gimple.h" |
c7131fb2 | 265 | #include "ssa.h" |
957060b5 | 266 | #include "gimple-pretty-print.h" |
c7131fb2 | 267 | #include "fold-const.h" |
45b0be94 | 268 | #include "gimplify.h" |
5be5c238 | 269 | #include "gimple-iterator.h" |
18f429e2 | 270 | #include "gimplify-me.h" |
442b4905 | 271 | #include "tree-cfg.h" |
e28030cf AM |
272 | #include "tree-ssa-loop-ivopts.h" |
273 | #include "tree-ssa-loop-manip.h" | |
274 | #include "tree-ssa-loop-niter.h" | |
442b4905 | 275 | #include "tree-ssa-loop.h" |
7a300452 | 276 | #include "tree-ssa.h" |
e9eb809d ZD |
277 | #include "cfgloop.h" |
278 | #include "tree-chrec.h" | |
b83b5507 | 279 | #include "tree-affine.h" |
e9eb809d | 280 | #include "tree-scalar-evolution.h" |
7ee2468b | 281 | #include "dumpfile.h" |
c59dabbe | 282 | #include "params.h" |
744730a4 | 283 | #include "tree-ssa-propagate.h" |
19e51b40 | 284 | #include "gimple-fold.h" |
24545562 | 285 | #include "tree-into-ssa.h" |
5126ae0c | 286 | #include "builtins.h" |
06a6b46a | 287 | #include "case-cfn-macros.h" |
9baba81b | 288 | |
fb1fe1f3 | 289 | static tree analyze_scalar_evolution_1 (struct loop *, tree); |
bef28ced JL |
290 | static tree analyze_scalar_evolution_for_address_of (struct loop *loop, |
291 | tree var); | |
9baba81b | 292 | |
a3cc13cc RB |
293 | /* The cached information about an SSA name with version NAME_VERSION, |
294 | claiming that below basic block with index INSTANTIATED_BELOW, the | |
295 | value of the SSA name can be expressed as CHREC. */ | |
9baba81b | 296 | |
907dadbd | 297 | struct GTY((for_user)) scev_info_str { |
a3cc13cc RB |
298 | unsigned int name_version; |
299 | int instantiated_below; | |
9baba81b SP |
300 | tree chrec; |
301 | }; | |
302 | ||
303 | /* Counters for the scev database. */ | |
304 | static unsigned nb_set_scev = 0; | |
305 | static unsigned nb_get_scev = 0; | |
306 | ||
ca752f39 | 307 | struct scev_info_hasher : ggc_ptr_hash<scev_info_str> |
907dadbd TS |
308 | { |
309 | static hashval_t hash (scev_info_str *i); | |
310 | static bool equal (const scev_info_str *a, const scev_info_str *b); | |
311 | }; | |
312 | ||
313 | static GTY (()) hash_table<scev_info_hasher> *scalar_evolution_info; | |
9baba81b SP |
314 | |
315 | \f | |
a213b219 | 316 | /* Constructs a new SCEV_INFO_STR structure for VAR and INSTANTIATED_BELOW. */ |
9baba81b SP |
317 | |
318 | static inline struct scev_info_str * | |
a213b219 | 319 | new_scev_info_str (basic_block instantiated_below, tree var) |
9baba81b SP |
320 | { |
321 | struct scev_info_str *res; | |
b8698a0f | 322 | |
766090c2 | 323 | res = ggc_alloc<scev_info_str> (); |
a3cc13cc | 324 | res->name_version = SSA_NAME_VERSION (var); |
9baba81b | 325 | res->chrec = chrec_not_analyzed_yet; |
a3cc13cc | 326 | res->instantiated_below = instantiated_below->index; |
a213b219 | 327 | |
9baba81b SP |
328 | return res; |
329 | } | |
330 | ||
331 | /* Computes a hash function for database element ELT. */ | |
332 | ||
907dadbd TS |
333 | hashval_t |
334 | scev_info_hasher::hash (scev_info_str *elt) | |
9baba81b | 335 | { |
a3cc13cc | 336 | return elt->name_version ^ elt->instantiated_below; |
9baba81b SP |
337 | } |
338 | ||
339 | /* Compares database elements E1 and E2. */ | |
340 | ||
907dadbd TS |
341 | bool |
342 | scev_info_hasher::equal (const scev_info_str *elt1, const scev_info_str *elt2) | |
9baba81b | 343 | { |
a3cc13cc | 344 | return (elt1->name_version == elt2->name_version |
a213b219 | 345 | && elt1->instantiated_below == elt2->instantiated_below); |
9baba81b SP |
346 | } |
347 | ||
a213b219 SP |
348 | /* Get the scalar evolution of VAR for INSTANTIATED_BELOW basic block. |
349 | A first query on VAR returns chrec_not_analyzed_yet. */ | |
9baba81b SP |
350 | |
351 | static tree * | |
a213b219 | 352 | find_var_scev_info (basic_block instantiated_below, tree var) |
9baba81b SP |
353 | { |
354 | struct scev_info_str *res; | |
355 | struct scev_info_str tmp; | |
9baba81b | 356 | |
a3cc13cc RB |
357 | tmp.name_version = SSA_NAME_VERSION (var); |
358 | tmp.instantiated_below = instantiated_below->index; | |
907dadbd | 359 | scev_info_str **slot = scalar_evolution_info->find_slot (&tmp, INSERT); |
9baba81b SP |
360 | |
361 | if (!*slot) | |
a213b219 | 362 | *slot = new_scev_info_str (instantiated_below, var); |
907dadbd | 363 | res = *slot; |
9baba81b SP |
364 | |
365 | return &res->chrec; | |
366 | } | |
367 | ||
577d6588 RB |
368 | |
369 | /* Hashtable helpers for a temporary hash-table used when | |
370 | analyzing a scalar evolution, instantiating a CHREC or | |
371 | resolving mixers. */ | |
372 | ||
373 | struct instantiate_cache_type | |
374 | { | |
375 | htab_t map; | |
376 | vec<scev_info_str> entries; | |
377 | ||
378 | instantiate_cache_type () : map (NULL), entries (vNULL) {} | |
379 | ~instantiate_cache_type (); | |
380 | tree get (unsigned slot) { return entries[slot].chrec; } | |
381 | void set (unsigned slot, tree chrec) { entries[slot].chrec = chrec; } | |
382 | }; | |
383 | ||
384 | instantiate_cache_type::~instantiate_cache_type () | |
385 | { | |
386 | if (map != NULL) | |
387 | { | |
388 | htab_delete (map); | |
389 | entries.release (); | |
390 | } | |
391 | } | |
392 | ||
393 | /* Cache to avoid infinite recursion when instantiating an SSA name. | |
394 | Live during the outermost analyze_scalar_evolution, instantiate_scev | |
395 | or resolve_mixers call. */ | |
396 | static instantiate_cache_type *global_cache; | |
397 | ||
398 | ||
9baba81b SP |
399 | /* Return true when PHI is a loop-phi-node. */ |
400 | ||
401 | static bool | |
355fe088 | 402 | loop_phi_node_p (gimple *phi) |
9baba81b SP |
403 | { |
404 | /* The implementation of this function is based on the following | |
405 | property: "all the loop-phi-nodes of a loop are contained in the | |
406 | loop's header basic block". */ | |
407 | ||
726a989a | 408 | return loop_containing_stmt (phi)->header == gimple_bb (phi); |
9baba81b SP |
409 | } |
410 | ||
411 | /* Compute the scalar evolution for EVOLUTION_FN after crossing LOOP. | |
412 | In general, in the case of multivariate evolutions we want to get | |
413 | the evolution in different loops. LOOP specifies the level for | |
414 | which to get the evolution. | |
b8698a0f | 415 | |
9baba81b | 416 | Example: |
b8698a0f | 417 | |
9baba81b SP |
418 | | for (j = 0; j < 100; j++) |
419 | | { | |
420 | | for (k = 0; k < 100; k++) | |
421 | | { | |
b8698a0f | 422 | | i = k + j; - Here the value of i is a function of j, k. |
9baba81b | 423 | | } |
b8698a0f | 424 | | ... = i - Here the value of i is a function of j. |
9baba81b | 425 | | } |
b8698a0f L |
426 | | ... = i - Here the value of i is a scalar. |
427 | ||
428 | Example: | |
429 | ||
9baba81b SP |
430 | | i_0 = ... |
431 | | loop_1 10 times | |
432 | | i_1 = phi (i_0, i_2) | |
433 | | i_2 = i_1 + 2 | |
434 | | endloop | |
b8698a0f | 435 | |
9baba81b SP |
436 | This loop has the same effect as: |
437 | LOOP_1 has the same effect as: | |
b8698a0f | 438 | |
9baba81b | 439 | | i_1 = i_0 + 20 |
b8698a0f L |
440 | |
441 | The overall effect of the loop, "i_0 + 20" in the previous example, | |
442 | is obtained by passing in the parameters: LOOP = 1, | |
9baba81b SP |
443 | EVOLUTION_FN = {i_0, +, 2}_1. |
444 | */ | |
b8698a0f | 445 | |
42e6eec5 | 446 | tree |
9baba81b SP |
447 | compute_overall_effect_of_inner_loop (struct loop *loop, tree evolution_fn) |
448 | { | |
449 | bool val = false; | |
450 | ||
451 | if (evolution_fn == chrec_dont_know) | |
452 | return chrec_dont_know; | |
453 | ||
454 | else if (TREE_CODE (evolution_fn) == POLYNOMIAL_CHREC) | |
455 | { | |
677cc14d ZD |
456 | struct loop *inner_loop = get_chrec_loop (evolution_fn); |
457 | ||
458 | if (inner_loop == loop | |
459 | || flow_loop_nested_p (loop, inner_loop)) | |
9baba81b | 460 | { |
a14865db | 461 | tree nb_iter = number_of_latch_executions (inner_loop); |
9baba81b SP |
462 | |
463 | if (nb_iter == chrec_dont_know) | |
464 | return chrec_dont_know; | |
465 | else | |
466 | { | |
467 | tree res; | |
468 | ||
9baba81b SP |
469 | /* evolution_fn is the evolution function in LOOP. Get |
470 | its value in the nb_iter-th iteration. */ | |
471 | res = chrec_apply (inner_loop->num, evolution_fn, nb_iter); | |
42e6eec5 SP |
472 | |
473 | if (chrec_contains_symbols_defined_in_loop (res, loop->num)) | |
474 | res = instantiate_parameters (loop, res); | |
475 | ||
8c27b7d4 | 476 | /* Continue the computation until ending on a parent of LOOP. */ |
9baba81b SP |
477 | return compute_overall_effect_of_inner_loop (loop, res); |
478 | } | |
479 | } | |
480 | else | |
481 | return evolution_fn; | |
482 | } | |
b8698a0f | 483 | |
9baba81b SP |
484 | /* If the evolution function is an invariant, there is nothing to do. */ |
485 | else if (no_evolution_in_loop_p (evolution_fn, loop->num, &val) && val) | |
486 | return evolution_fn; | |
b8698a0f | 487 | |
9baba81b SP |
488 | else |
489 | return chrec_dont_know; | |
490 | } | |
491 | ||
9baba81b SP |
492 | /* Associate CHREC to SCALAR. */ |
493 | ||
494 | static void | |
a213b219 | 495 | set_scalar_evolution (basic_block instantiated_below, tree scalar, tree chrec) |
9baba81b SP |
496 | { |
497 | tree *scalar_info; | |
b8698a0f | 498 | |
9baba81b SP |
499 | if (TREE_CODE (scalar) != SSA_NAME) |
500 | return; | |
501 | ||
a213b219 | 502 | scalar_info = find_var_scev_info (instantiated_below, scalar); |
b8698a0f | 503 | |
9baba81b SP |
504 | if (dump_file) |
505 | { | |
dfedbe40 | 506 | if (dump_flags & TDF_SCEV) |
9baba81b SP |
507 | { |
508 | fprintf (dump_file, "(set_scalar_evolution \n"); | |
a213b219 SP |
509 | fprintf (dump_file, " instantiated_below = %d \n", |
510 | instantiated_below->index); | |
9baba81b | 511 | fprintf (dump_file, " (scalar = "); |
ef6cb4c7 | 512 | print_generic_expr (dump_file, scalar); |
9baba81b | 513 | fprintf (dump_file, ")\n (scalar_evolution = "); |
ef6cb4c7 | 514 | print_generic_expr (dump_file, chrec); |
9baba81b SP |
515 | fprintf (dump_file, "))\n"); |
516 | } | |
517 | if (dump_flags & TDF_STATS) | |
518 | nb_set_scev++; | |
519 | } | |
b8698a0f | 520 | |
9baba81b SP |
521 | *scalar_info = chrec; |
522 | } | |
523 | ||
a213b219 SP |
524 | /* Retrieve the chrec associated to SCALAR instantiated below |
525 | INSTANTIATED_BELOW block. */ | |
9baba81b SP |
526 | |
527 | static tree | |
a213b219 | 528 | get_scalar_evolution (basic_block instantiated_below, tree scalar) |
9baba81b SP |
529 | { |
530 | tree res; | |
b8698a0f | 531 | |
9baba81b SP |
532 | if (dump_file) |
533 | { | |
dfedbe40 | 534 | if (dump_flags & TDF_SCEV) |
9baba81b SP |
535 | { |
536 | fprintf (dump_file, "(get_scalar_evolution \n"); | |
537 | fprintf (dump_file, " (scalar = "); | |
ef6cb4c7 | 538 | print_generic_expr (dump_file, scalar); |
9baba81b SP |
539 | fprintf (dump_file, ")\n"); |
540 | } | |
541 | if (dump_flags & TDF_STATS) | |
542 | nb_get_scev++; | |
543 | } | |
b8698a0f | 544 | |
5355943c RB |
545 | if (VECTOR_TYPE_P (TREE_TYPE (scalar)) |
546 | || TREE_CODE (TREE_TYPE (scalar)) == COMPLEX_TYPE) | |
547 | /* For chrec_dont_know we keep the symbolic form. */ | |
548 | res = scalar; | |
549 | else | |
550 | switch (TREE_CODE (scalar)) | |
551 | { | |
552 | case SSA_NAME: | |
553 | if (SSA_NAME_IS_DEFAULT_DEF (scalar)) | |
554 | res = scalar; | |
555 | else | |
556 | res = *find_var_scev_info (instantiated_below, scalar); | |
557 | break; | |
9baba81b | 558 | |
5355943c RB |
559 | case REAL_CST: |
560 | case FIXED_CST: | |
561 | case INTEGER_CST: | |
562 | res = scalar; | |
563 | break; | |
9baba81b | 564 | |
5355943c RB |
565 | default: |
566 | res = chrec_not_analyzed_yet; | |
567 | break; | |
568 | } | |
b8698a0f | 569 | |
dfedbe40 | 570 | if (dump_file && (dump_flags & TDF_SCEV)) |
9baba81b SP |
571 | { |
572 | fprintf (dump_file, " (scalar_evolution = "); | |
ef6cb4c7 | 573 | print_generic_expr (dump_file, res); |
9baba81b SP |
574 | fprintf (dump_file, "))\n"); |
575 | } | |
b8698a0f | 576 | |
9baba81b SP |
577 | return res; |
578 | } | |
579 | ||
580 | /* Helper function for add_to_evolution. Returns the evolution | |
581 | function for an assignment of the form "a = b + c", where "a" and | |
582 | "b" are on the strongly connected component. CHREC_BEFORE is the | |
583 | information that we already have collected up to this point. | |
b8698a0f L |
584 | TO_ADD is the evolution of "c". |
585 | ||
9baba81b SP |
586 | When CHREC_BEFORE has an evolution part in LOOP_NB, add to this |
587 | evolution the expression TO_ADD, otherwise construct an evolution | |
588 | part for this loop. */ | |
589 | ||
590 | static tree | |
e2157b49 | 591 | add_to_evolution_1 (unsigned loop_nb, tree chrec_before, tree to_add, |
355fe088 | 592 | gimple *at_stmt) |
9baba81b | 593 | { |
e2157b49 | 594 | tree type, left, right; |
0fc822d0 | 595 | struct loop *loop = get_loop (cfun, loop_nb), *chloop; |
e2157b49 | 596 | |
9baba81b SP |
597 | switch (TREE_CODE (chrec_before)) |
598 | { | |
599 | case POLYNOMIAL_CHREC: | |
677cc14d ZD |
600 | chloop = get_chrec_loop (chrec_before); |
601 | if (chloop == loop | |
602 | || flow_loop_nested_p (chloop, loop)) | |
9baba81b SP |
603 | { |
604 | unsigned var; | |
e2157b49 SP |
605 | |
606 | type = chrec_type (chrec_before); | |
b8698a0f | 607 | |
9baba81b | 608 | /* When there is no evolution part in this loop, build it. */ |
677cc14d | 609 | if (chloop != loop) |
9baba81b SP |
610 | { |
611 | var = loop_nb; | |
612 | left = chrec_before; | |
7e0923cd SP |
613 | right = SCALAR_FLOAT_TYPE_P (type) |
614 | ? build_real (type, dconst0) | |
615 | : build_int_cst (type, 0); | |
9baba81b SP |
616 | } |
617 | else | |
618 | { | |
619 | var = CHREC_VARIABLE (chrec_before); | |
620 | left = CHREC_LEFT (chrec_before); | |
621 | right = CHREC_RIGHT (chrec_before); | |
622 | } | |
623 | ||
e2157b49 | 624 | to_add = chrec_convert (type, to_add, at_stmt); |
5be014d5 AP |
625 | right = chrec_convert_rhs (type, right, at_stmt); |
626 | right = chrec_fold_plus (chrec_type (right), right, to_add); | |
e2157b49 | 627 | return build_polynomial_chrec (var, left, right); |
9baba81b SP |
628 | } |
629 | else | |
e2157b49 | 630 | { |
677cc14d ZD |
631 | gcc_assert (flow_loop_nested_p (loop, chloop)); |
632 | ||
e2157b49 SP |
633 | /* Search the evolution in LOOP_NB. */ |
634 | left = add_to_evolution_1 (loop_nb, CHREC_LEFT (chrec_before), | |
635 | to_add, at_stmt); | |
636 | right = CHREC_RIGHT (chrec_before); | |
5be014d5 | 637 | right = chrec_convert_rhs (chrec_type (left), right, at_stmt); |
e2157b49 SP |
638 | return build_polynomial_chrec (CHREC_VARIABLE (chrec_before), |
639 | left, right); | |
640 | } | |
b8698a0f | 641 | |
9baba81b SP |
642 | default: |
643 | /* These nodes do not depend on a loop. */ | |
644 | if (chrec_before == chrec_dont_know) | |
645 | return chrec_dont_know; | |
e2157b49 SP |
646 | |
647 | left = chrec_before; | |
5be014d5 | 648 | right = chrec_convert_rhs (chrec_type (left), to_add, at_stmt); |
e2157b49 | 649 | return build_polynomial_chrec (loop_nb, left, right); |
9baba81b SP |
650 | } |
651 | } | |
652 | ||
653 | /* Add TO_ADD to the evolution part of CHREC_BEFORE in the dimension | |
b8698a0f L |
654 | of LOOP_NB. |
655 | ||
9baba81b SP |
656 | Description (provided for completeness, for those who read code in |
657 | a plane, and for my poor 62 bytes brain that would have forgotten | |
658 | all this in the next two or three months): | |
b8698a0f | 659 | |
9baba81b SP |
660 | The algorithm of translation of programs from the SSA representation |
661 | into the chrecs syntax is based on a pattern matching. After having | |
662 | reconstructed the overall tree expression for a loop, there are only | |
663 | two cases that can arise: | |
b8698a0f | 664 | |
9baba81b SP |
665 | 1. a = loop-phi (init, a + expr) |
666 | 2. a = loop-phi (init, expr) | |
b8698a0f | 667 | |
9baba81b SP |
668 | where EXPR is either a scalar constant with respect to the analyzed |
669 | loop (this is a degree 0 polynomial), or an expression containing | |
670 | other loop-phi definitions (these are higher degree polynomials). | |
b8698a0f | 671 | |
9baba81b | 672 | Examples: |
b8698a0f L |
673 | |
674 | 1. | |
9baba81b SP |
675 | | init = ... |
676 | | loop_1 | |
677 | | a = phi (init, a + 5) | |
678 | | endloop | |
b8698a0f L |
679 | |
680 | 2. | |
9baba81b SP |
681 | | inita = ... |
682 | | initb = ... | |
683 | | loop_1 | |
684 | | a = phi (inita, 2 * b + 3) | |
685 | | b = phi (initb, b + 1) | |
686 | | endloop | |
b8698a0f L |
687 | |
688 | For the first case, the semantics of the SSA representation is: | |
689 | ||
9baba81b | 690 | | a (x) = init + \sum_{j = 0}^{x - 1} expr (j) |
b8698a0f | 691 | |
9baba81b SP |
692 | that is, there is a loop index "x" that determines the scalar value |
693 | of the variable during the loop execution. During the first | |
694 | iteration, the value is that of the initial condition INIT, while | |
695 | during the subsequent iterations, it is the sum of the initial | |
696 | condition with the sum of all the values of EXPR from the initial | |
b8698a0f L |
697 | iteration to the before last considered iteration. |
698 | ||
9baba81b | 699 | For the second case, the semantics of the SSA program is: |
b8698a0f | 700 | |
9baba81b SP |
701 | | a (x) = init, if x = 0; |
702 | | expr (x - 1), otherwise. | |
b8698a0f | 703 | |
9baba81b | 704 | The second case corresponds to the PEELED_CHREC, whose syntax is |
b8698a0f L |
705 | close to the syntax of a loop-phi-node: |
706 | ||
9baba81b | 707 | | phi (init, expr) vs. (init, expr)_x |
b8698a0f | 708 | |
9baba81b | 709 | The proof of the translation algorithm for the first case is a |
b8698a0f L |
710 | proof by structural induction based on the degree of EXPR. |
711 | ||
9baba81b SP |
712 | Degree 0: |
713 | When EXPR is a constant with respect to the analyzed loop, or in | |
714 | other words when EXPR is a polynomial of degree 0, the evolution of | |
715 | the variable A in the loop is an affine function with an initial | |
716 | condition INIT, and a step EXPR. In order to show this, we start | |
717 | from the semantics of the SSA representation: | |
b8698a0f | 718 | |
9baba81b | 719 | f (x) = init + \sum_{j = 0}^{x - 1} expr (j) |
b8698a0f | 720 | |
9baba81b | 721 | and since "expr (j)" is a constant with respect to "j", |
b8698a0f L |
722 | |
723 | f (x) = init + x * expr | |
724 | ||
9baba81b SP |
725 | Finally, based on the semantics of the pure sum chrecs, by |
726 | identification we get the corresponding chrecs syntax: | |
b8698a0f L |
727 | |
728 | f (x) = init * \binom{x}{0} + expr * \binom{x}{1} | |
9baba81b | 729 | f (x) -> {init, +, expr}_x |
b8698a0f | 730 | |
9baba81b SP |
731 | Higher degree: |
732 | Suppose that EXPR is a polynomial of degree N with respect to the | |
733 | analyzed loop_x for which we have already determined that it is | |
734 | written under the chrecs syntax: | |
b8698a0f | 735 | |
9baba81b | 736 | | expr (x) -> {b_0, +, b_1, +, ..., +, b_{n-1}} (x) |
b8698a0f | 737 | |
9baba81b | 738 | We start from the semantics of the SSA program: |
b8698a0f | 739 | |
9baba81b SP |
740 | | f (x) = init + \sum_{j = 0}^{x - 1} expr (j) |
741 | | | |
b8698a0f | 742 | | f (x) = init + \sum_{j = 0}^{x - 1} |
9baba81b SP |
743 | | (b_0 * \binom{j}{0} + ... + b_{n-1} * \binom{j}{n-1}) |
744 | | | |
b8698a0f L |
745 | | f (x) = init + \sum_{j = 0}^{x - 1} |
746 | | \sum_{k = 0}^{n - 1} (b_k * \binom{j}{k}) | |
9baba81b | 747 | | |
b8698a0f L |
748 | | f (x) = init + \sum_{k = 0}^{n - 1} |
749 | | (b_k * \sum_{j = 0}^{x - 1} \binom{j}{k}) | |
9baba81b | 750 | | |
b8698a0f L |
751 | | f (x) = init + \sum_{k = 0}^{n - 1} |
752 | | (b_k * \binom{x}{k + 1}) | |
9baba81b | 753 | | |
b8698a0f L |
754 | | f (x) = init + b_0 * \binom{x}{1} + ... |
755 | | + b_{n-1} * \binom{x}{n} | |
9baba81b | 756 | | |
b8698a0f L |
757 | | f (x) = init * \binom{x}{0} + b_0 * \binom{x}{1} + ... |
758 | | + b_{n-1} * \binom{x}{n} | |
9baba81b | 759 | | |
b8698a0f | 760 | |
9baba81b | 761 | And finally from the definition of the chrecs syntax, we identify: |
b8698a0f L |
762 | | f (x) -> {init, +, b_0, +, ..., +, b_{n-1}}_x |
763 | ||
9baba81b SP |
764 | This shows the mechanism that stands behind the add_to_evolution |
765 | function. An important point is that the use of symbolic | |
766 | parameters avoids the need of an analysis schedule. | |
b8698a0f | 767 | |
9baba81b | 768 | Example: |
b8698a0f | 769 | |
9baba81b SP |
770 | | inita = ... |
771 | | initb = ... | |
b8698a0f | 772 | | loop_1 |
9baba81b SP |
773 | | a = phi (inita, a + 2 + b) |
774 | | b = phi (initb, b + 1) | |
775 | | endloop | |
b8698a0f | 776 | |
9baba81b | 777 | When analyzing "a", the algorithm keeps "b" symbolically: |
b8698a0f | 778 | |
9baba81b | 779 | | a -> {inita, +, 2 + b}_1 |
b8698a0f | 780 | |
9baba81b | 781 | Then, after instantiation, the analyzer ends on the evolution: |
b8698a0f | 782 | |
9baba81b SP |
783 | | a -> {inita, +, 2 + initb, +, 1}_1 |
784 | ||
785 | */ | |
786 | ||
b8698a0f | 787 | static tree |
e2157b49 | 788 | add_to_evolution (unsigned loop_nb, tree chrec_before, enum tree_code code, |
355fe088 | 789 | tree to_add, gimple *at_stmt) |
9baba81b SP |
790 | { |
791 | tree type = chrec_type (to_add); | |
792 | tree res = NULL_TREE; | |
b8698a0f | 793 | |
9baba81b SP |
794 | if (to_add == NULL_TREE) |
795 | return chrec_before; | |
b8698a0f | 796 | |
9baba81b SP |
797 | /* TO_ADD is either a scalar, or a parameter. TO_ADD is not |
798 | instantiated at this point. */ | |
799 | if (TREE_CODE (to_add) == POLYNOMIAL_CHREC) | |
800 | /* This should not happen. */ | |
801 | return chrec_dont_know; | |
b8698a0f | 802 | |
dfedbe40 | 803 | if (dump_file && (dump_flags & TDF_SCEV)) |
9baba81b SP |
804 | { |
805 | fprintf (dump_file, "(add_to_evolution \n"); | |
806 | fprintf (dump_file, " (loop_nb = %d)\n", loop_nb); | |
807 | fprintf (dump_file, " (chrec_before = "); | |
ef6cb4c7 | 808 | print_generic_expr (dump_file, chrec_before); |
9baba81b | 809 | fprintf (dump_file, ")\n (to_add = "); |
ef6cb4c7 | 810 | print_generic_expr (dump_file, to_add); |
9baba81b SP |
811 | fprintf (dump_file, ")\n"); |
812 | } | |
813 | ||
814 | if (code == MINUS_EXPR) | |
9d2b0e12 VR |
815 | to_add = chrec_fold_multiply (type, to_add, SCALAR_FLOAT_TYPE_P (type) |
816 | ? build_real (type, dconstm1) | |
817 | : build_int_cst_type (type, -1)); | |
9baba81b | 818 | |
e2157b49 | 819 | res = add_to_evolution_1 (loop_nb, chrec_before, to_add, at_stmt); |
9baba81b | 820 | |
dfedbe40 | 821 | if (dump_file && (dump_flags & TDF_SCEV)) |
9baba81b SP |
822 | { |
823 | fprintf (dump_file, " (res = "); | |
ef6cb4c7 | 824 | print_generic_expr (dump_file, res); |
9baba81b SP |
825 | fprintf (dump_file, "))\n"); |
826 | } | |
827 | ||
828 | return res; | |
829 | } | |
830 | ||
9baba81b SP |
831 | \f |
832 | ||
833 | /* This section selects the loops that will be good candidates for the | |
834 | scalar evolution analysis. For the moment, greedily select all the | |
835 | loop nests we could analyze. */ | |
836 | ||
9baba81b SP |
837 | /* For a loop with a single exit edge, return the COND_EXPR that |
838 | guards the exit edge. If the expression is too difficult to | |
839 | analyze, then give up. */ | |
840 | ||
538dd0b7 | 841 | gcond * |
22ea9ec0 | 842 | get_loop_exit_condition (const struct loop *loop) |
9baba81b | 843 | { |
538dd0b7 | 844 | gcond *res = NULL; |
ac8f6c69 | 845 | edge exit_edge = single_exit (loop); |
b8698a0f | 846 | |
dfedbe40 | 847 | if (dump_file && (dump_flags & TDF_SCEV)) |
9baba81b | 848 | fprintf (dump_file, "(get_loop_exit_condition \n "); |
b8698a0f | 849 | |
82b85a85 | 850 | if (exit_edge) |
9baba81b | 851 | { |
355fe088 | 852 | gimple *stmt; |
b8698a0f | 853 | |
726a989a | 854 | stmt = last_stmt (exit_edge->src); |
19d4e4d6 | 855 | if (gcond *cond_stmt = safe_dyn_cast <gcond *> (stmt)) |
538dd0b7 | 856 | res = cond_stmt; |
9baba81b | 857 | } |
b8698a0f | 858 | |
dfedbe40 | 859 | if (dump_file && (dump_flags & TDF_SCEV)) |
9baba81b | 860 | { |
ef6cb4c7 | 861 | print_gimple_stmt (dump_file, res, 0); |
9baba81b SP |
862 | fprintf (dump_file, ")\n"); |
863 | } | |
b8698a0f | 864 | |
9baba81b SP |
865 | return res; |
866 | } | |
867 | ||
9baba81b SP |
868 | \f |
869 | /* Depth first search algorithm. */ | |
870 | ||
a79683d5 | 871 | enum t_bool { |
c59dabbe SP |
872 | t_false, |
873 | t_true, | |
874 | t_dont_know | |
a79683d5 | 875 | }; |
c59dabbe SP |
876 | |
877 | ||
355fe088 | 878 | static t_bool follow_ssa_edge (struct loop *loop, gimple *, gphi *, |
538dd0b7 | 879 | tree *, int); |
9baba81b | 880 | |
726a989a | 881 | /* Follow the ssa edge into the binary expression RHS0 CODE RHS1. |
9baba81b SP |
882 | Return true if the strongly connected component has been found. */ |
883 | ||
c59dabbe | 884 | static t_bool |
355fe088 | 885 | follow_ssa_edge_binary (struct loop *loop, gimple *at_stmt, |
726a989a | 886 | tree type, tree rhs0, enum tree_code code, tree rhs1, |
538dd0b7 DM |
887 | gphi *halting_phi, tree *evolution_of_loop, |
888 | int limit) | |
9baba81b | 889 | { |
c59dabbe | 890 | t_bool res = t_false; |
b2a93c0a | 891 | tree evol; |
726a989a | 892 | |
5be014d5 | 893 | switch (code) |
9baba81b | 894 | { |
5be014d5 | 895 | case POINTER_PLUS_EXPR: |
9baba81b | 896 | case PLUS_EXPR: |
9baba81b SP |
897 | if (TREE_CODE (rhs0) == SSA_NAME) |
898 | { | |
899 | if (TREE_CODE (rhs1) == SSA_NAME) | |
900 | { | |
b8698a0f | 901 | /* Match an assignment under the form: |
9baba81b | 902 | "a = b + c". */ |
b8698a0f | 903 | |
9e824336 ZD |
904 | /* We want only assignments of form "name + name" contribute to |
905 | LIMIT, as the other cases do not necessarily contribute to | |
906 | the complexity of the expression. */ | |
907 | limit++; | |
908 | ||
b2a93c0a | 909 | evol = *evolution_of_loop; |
b9b79ba4 | 910 | evol = add_to_evolution |
b8698a0f L |
911 | (loop->num, |
912 | chrec_convert (type, evol, at_stmt), | |
5be014d5 | 913 | code, rhs1, at_stmt); |
b9b79ba4 RB |
914 | res = follow_ssa_edge |
915 | (loop, SSA_NAME_DEF_STMT (rhs0), halting_phi, &evol, limit); | |
916 | if (res == t_true) | |
917 | *evolution_of_loop = evol; | |
c59dabbe | 918 | else if (res == t_false) |
9baba81b | 919 | { |
b9b79ba4 RB |
920 | *evolution_of_loop = add_to_evolution |
921 | (loop->num, | |
922 | chrec_convert (type, *evolution_of_loop, at_stmt), | |
923 | code, rhs0, at_stmt); | |
b8698a0f L |
924 | res = follow_ssa_edge |
925 | (loop, SSA_NAME_DEF_STMT (rhs1), halting_phi, | |
c59dabbe | 926 | evolution_of_loop, limit); |
c59dabbe | 927 | if (res == t_true) |
b9b79ba4 | 928 | ; |
c59dabbe SP |
929 | else if (res == t_dont_know) |
930 | *evolution_of_loop = chrec_dont_know; | |
9baba81b | 931 | } |
c59dabbe SP |
932 | |
933 | else if (res == t_dont_know) | |
934 | *evolution_of_loop = chrec_dont_know; | |
9baba81b | 935 | } |
b8698a0f | 936 | |
9baba81b SP |
937 | else |
938 | { | |
b8698a0f | 939 | /* Match an assignment under the form: |
9baba81b | 940 | "a = b + ...". */ |
b9b79ba4 RB |
941 | *evolution_of_loop = add_to_evolution |
942 | (loop->num, chrec_convert (type, *evolution_of_loop, | |
943 | at_stmt), | |
944 | code, rhs1, at_stmt); | |
b8698a0f L |
945 | res = follow_ssa_edge |
946 | (loop, SSA_NAME_DEF_STMT (rhs0), halting_phi, | |
c59dabbe SP |
947 | evolution_of_loop, limit); |
948 | if (res == t_true) | |
b9b79ba4 | 949 | ; |
c59dabbe SP |
950 | else if (res == t_dont_know) |
951 | *evolution_of_loop = chrec_dont_know; | |
9baba81b SP |
952 | } |
953 | } | |
b8698a0f | 954 | |
9baba81b SP |
955 | else if (TREE_CODE (rhs1) == SSA_NAME) |
956 | { | |
b8698a0f | 957 | /* Match an assignment under the form: |
9baba81b | 958 | "a = ... + c". */ |
b9b79ba4 RB |
959 | *evolution_of_loop = add_to_evolution |
960 | (loop->num, chrec_convert (type, *evolution_of_loop, | |
961 | at_stmt), | |
962 | code, rhs0, at_stmt); | |
b8698a0f L |
963 | res = follow_ssa_edge |
964 | (loop, SSA_NAME_DEF_STMT (rhs1), halting_phi, | |
c59dabbe SP |
965 | evolution_of_loop, limit); |
966 | if (res == t_true) | |
b9b79ba4 | 967 | ; |
c59dabbe SP |
968 | else if (res == t_dont_know) |
969 | *evolution_of_loop = chrec_dont_know; | |
9baba81b SP |
970 | } |
971 | ||
972 | else | |
b8698a0f | 973 | /* Otherwise, match an assignment under the form: |
9baba81b SP |
974 | "a = ... + ...". */ |
975 | /* And there is nothing to do. */ | |
c59dabbe | 976 | res = t_false; |
9baba81b | 977 | break; |
b8698a0f | 978 | |
9baba81b SP |
979 | case MINUS_EXPR: |
980 | /* This case is under the form "opnd0 = rhs0 - rhs1". */ | |
9baba81b | 981 | if (TREE_CODE (rhs0) == SSA_NAME) |
9baba81b | 982 | { |
b8698a0f | 983 | /* Match an assignment under the form: |
f8e9d512 | 984 | "a = b - ...". */ |
9e824336 ZD |
985 | |
986 | /* We want only assignments of form "name - name" contribute to | |
987 | LIMIT, as the other cases do not necessarily contribute to | |
988 | the complexity of the expression. */ | |
989 | if (TREE_CODE (rhs1) == SSA_NAME) | |
990 | limit++; | |
991 | ||
b9b79ba4 RB |
992 | *evolution_of_loop = add_to_evolution |
993 | (loop->num, chrec_convert (type, *evolution_of_loop, at_stmt), | |
994 | MINUS_EXPR, rhs1, at_stmt); | |
b8698a0f | 995 | res = follow_ssa_edge (loop, SSA_NAME_DEF_STMT (rhs0), halting_phi, |
c59dabbe SP |
996 | evolution_of_loop, limit); |
997 | if (res == t_true) | |
b9b79ba4 | 998 | ; |
c59dabbe SP |
999 | else if (res == t_dont_know) |
1000 | *evolution_of_loop = chrec_dont_know; | |
9baba81b | 1001 | } |
9baba81b | 1002 | else |
b8698a0f | 1003 | /* Otherwise, match an assignment under the form: |
9baba81b SP |
1004 | "a = ... - ...". */ |
1005 | /* And there is nothing to do. */ | |
c59dabbe | 1006 | res = t_false; |
9baba81b | 1007 | break; |
726a989a RB |
1008 | |
1009 | default: | |
1010 | res = t_false; | |
1011 | } | |
1012 | ||
1013 | return res; | |
1014 | } | |
b8698a0f | 1015 | |
726a989a RB |
1016 | /* Follow the ssa edge into the expression EXPR. |
1017 | Return true if the strongly connected component has been found. */ | |
1018 | ||
1019 | static t_bool | |
355fe088 | 1020 | follow_ssa_edge_expr (struct loop *loop, gimple *at_stmt, tree expr, |
538dd0b7 DM |
1021 | gphi *halting_phi, tree *evolution_of_loop, |
1022 | int limit) | |
726a989a | 1023 | { |
5aefc6a0 EB |
1024 | enum tree_code code = TREE_CODE (expr); |
1025 | tree type = TREE_TYPE (expr), rhs0, rhs1; | |
1026 | t_bool res; | |
1027 | ||
726a989a | 1028 | /* The EXPR is one of the following cases: |
b8698a0f | 1029 | - an SSA_NAME, |
726a989a | 1030 | - an INTEGER_CST, |
b8698a0f L |
1031 | - a PLUS_EXPR, |
1032 | - a POINTER_PLUS_EXPR, | |
726a989a RB |
1033 | - a MINUS_EXPR, |
1034 | - an ASSERT_EXPR, | |
1035 | - other cases are not yet handled. */ | |
5aefc6a0 | 1036 | |
726a989a RB |
1037 | switch (code) |
1038 | { | |
5aefc6a0 | 1039 | CASE_CONVERT: |
726a989a RB |
1040 | /* This assignment is under the form "a_1 = (cast) rhs. */ |
1041 | res = follow_ssa_edge_expr (loop, at_stmt, TREE_OPERAND (expr, 0), | |
1042 | halting_phi, evolution_of_loop, limit); | |
1043 | *evolution_of_loop = chrec_convert (type, *evolution_of_loop, at_stmt); | |
1044 | break; | |
1045 | ||
1046 | case INTEGER_CST: | |
1047 | /* This assignment is under the form "a_1 = 7". */ | |
1048 | res = t_false; | |
1049 | break; | |
5aefc6a0 | 1050 | |
726a989a RB |
1051 | case SSA_NAME: |
1052 | /* This assignment is under the form: "a_1 = b_2". */ | |
b8698a0f | 1053 | res = follow_ssa_edge |
726a989a RB |
1054 | (loop, SSA_NAME_DEF_STMT (expr), halting_phi, evolution_of_loop, limit); |
1055 | break; | |
5aefc6a0 | 1056 | |
726a989a RB |
1057 | case POINTER_PLUS_EXPR: |
1058 | case PLUS_EXPR: | |
1059 | case MINUS_EXPR: | |
1060 | /* This case is under the form "rhs0 +- rhs1". */ | |
1061 | rhs0 = TREE_OPERAND (expr, 0); | |
1062 | rhs1 = TREE_OPERAND (expr, 1); | |
5aefc6a0 EB |
1063 | type = TREE_TYPE (rhs0); |
1064 | STRIP_USELESS_TYPE_CONVERSION (rhs0); | |
1065 | STRIP_USELESS_TYPE_CONVERSION (rhs1); | |
1066 | res = follow_ssa_edge_binary (loop, at_stmt, type, rhs0, code, rhs1, | |
1067 | halting_phi, evolution_of_loop, limit); | |
1068 | break; | |
726a989a | 1069 | |
70f34814 RG |
1070 | case ADDR_EXPR: |
1071 | /* Handle &MEM[ptr + CST] which is equivalent to POINTER_PLUS_EXPR. */ | |
1072 | if (TREE_CODE (TREE_OPERAND (expr, 0)) == MEM_REF) | |
1073 | { | |
1074 | expr = TREE_OPERAND (expr, 0); | |
1075 | rhs0 = TREE_OPERAND (expr, 0); | |
1076 | rhs1 = TREE_OPERAND (expr, 1); | |
1077 | type = TREE_TYPE (rhs0); | |
1078 | STRIP_USELESS_TYPE_CONVERSION (rhs0); | |
1079 | STRIP_USELESS_TYPE_CONVERSION (rhs1); | |
1080 | res = follow_ssa_edge_binary (loop, at_stmt, type, | |
1081 | rhs0, POINTER_PLUS_EXPR, rhs1, | |
1082 | halting_phi, evolution_of_loop, limit); | |
1083 | } | |
1084 | else | |
1085 | res = t_false; | |
1086 | break; | |
1087 | ||
0bca51f0 | 1088 | case ASSERT_EXPR: |
5aefc6a0 EB |
1089 | /* This assignment is of the form: "a_1 = ASSERT_EXPR <a_2, ...>" |
1090 | It must be handled as a copy assignment of the form a_1 = a_2. */ | |
1091 | rhs0 = ASSERT_EXPR_VAR (expr); | |
1092 | if (TREE_CODE (rhs0) == SSA_NAME) | |
1093 | res = follow_ssa_edge (loop, SSA_NAME_DEF_STMT (rhs0), | |
1094 | halting_phi, evolution_of_loop, limit); | |
1095 | else | |
1096 | res = t_false; | |
1097 | break; | |
0bca51f0 | 1098 | |
9baba81b | 1099 | default: |
c59dabbe | 1100 | res = t_false; |
9baba81b SP |
1101 | break; |
1102 | } | |
5aefc6a0 | 1103 | |
9baba81b SP |
1104 | return res; |
1105 | } | |
1106 | ||
726a989a RB |
1107 | /* Follow the ssa edge into the right hand side of an assignment STMT. |
1108 | Return true if the strongly connected component has been found. */ | |
1109 | ||
1110 | static t_bool | |
355fe088 | 1111 | follow_ssa_edge_in_rhs (struct loop *loop, gimple *stmt, |
538dd0b7 DM |
1112 | gphi *halting_phi, tree *evolution_of_loop, |
1113 | int limit) | |
726a989a | 1114 | { |
726a989a | 1115 | enum tree_code code = gimple_assign_rhs_code (stmt); |
5aefc6a0 EB |
1116 | tree type = gimple_expr_type (stmt), rhs1, rhs2; |
1117 | t_bool res; | |
726a989a | 1118 | |
5aefc6a0 | 1119 | switch (code) |
726a989a | 1120 | { |
5aefc6a0 EB |
1121 | CASE_CONVERT: |
1122 | /* This assignment is under the form "a_1 = (cast) rhs. */ | |
1123 | res = follow_ssa_edge_expr (loop, stmt, gimple_assign_rhs1 (stmt), | |
1124 | halting_phi, evolution_of_loop, limit); | |
1125 | *evolution_of_loop = chrec_convert (type, *evolution_of_loop, stmt); | |
1126 | break; | |
1127 | ||
1128 | case POINTER_PLUS_EXPR: | |
1129 | case PLUS_EXPR: | |
1130 | case MINUS_EXPR: | |
1131 | rhs1 = gimple_assign_rhs1 (stmt); | |
1132 | rhs2 = gimple_assign_rhs2 (stmt); | |
1133 | type = TREE_TYPE (rhs1); | |
1134 | res = follow_ssa_edge_binary (loop, stmt, type, rhs1, code, rhs2, | |
218d1c24 | 1135 | halting_phi, evolution_of_loop, limit); |
5aefc6a0 | 1136 | break; |
218d1c24 | 1137 | |
726a989a | 1138 | default: |
5aefc6a0 EB |
1139 | if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS) |
1140 | res = follow_ssa_edge_expr (loop, stmt, gimple_assign_rhs1 (stmt), | |
1141 | halting_phi, evolution_of_loop, limit); | |
1142 | else | |
1143 | res = t_false; | |
1144 | break; | |
726a989a | 1145 | } |
5aefc6a0 EB |
1146 | |
1147 | return res; | |
726a989a RB |
1148 | } |
1149 | ||
9baba81b SP |
1150 | /* Checks whether the I-th argument of a PHI comes from a backedge. */ |
1151 | ||
1152 | static bool | |
538dd0b7 | 1153 | backedge_phi_arg_p (gphi *phi, int i) |
9baba81b | 1154 | { |
726a989a | 1155 | const_edge e = gimple_phi_arg_edge (phi, i); |
9baba81b SP |
1156 | |
1157 | /* We would in fact like to test EDGE_DFS_BACK here, but we do not care | |
1158 | about updating it anywhere, and this should work as well most of the | |
1159 | time. */ | |
1160 | if (e->flags & EDGE_IRREDUCIBLE_LOOP) | |
1161 | return true; | |
1162 | ||
1163 | return false; | |
1164 | } | |
1165 | ||
1166 | /* Helper function for one branch of the condition-phi-node. Return | |
1167 | true if the strongly connected component has been found following | |
1168 | this path. */ | |
1169 | ||
c59dabbe | 1170 | static inline t_bool |
9baba81b | 1171 | follow_ssa_edge_in_condition_phi_branch (int i, |
b8698a0f | 1172 | struct loop *loop, |
538dd0b7 DM |
1173 | gphi *condition_phi, |
1174 | gphi *halting_phi, | |
9baba81b | 1175 | tree *evolution_of_branch, |
c59dabbe | 1176 | tree init_cond, int limit) |
9baba81b SP |
1177 | { |
1178 | tree branch = PHI_ARG_DEF (condition_phi, i); | |
1179 | *evolution_of_branch = chrec_dont_know; | |
1180 | ||
1181 | /* Do not follow back edges (they must belong to an irreducible loop, which | |
1182 | we really do not want to worry about). */ | |
1183 | if (backedge_phi_arg_p (condition_phi, i)) | |
c59dabbe | 1184 | return t_false; |
9baba81b SP |
1185 | |
1186 | if (TREE_CODE (branch) == SSA_NAME) | |
1187 | { | |
1188 | *evolution_of_branch = init_cond; | |
b8698a0f | 1189 | return follow_ssa_edge (loop, SSA_NAME_DEF_STMT (branch), halting_phi, |
c59dabbe | 1190 | evolution_of_branch, limit); |
9baba81b SP |
1191 | } |
1192 | ||
b8698a0f | 1193 | /* This case occurs when one of the condition branches sets |
89dbed81 | 1194 | the variable to a constant: i.e. a phi-node like |
b8698a0f L |
1195 | "a_2 = PHI <a_7(5), 2(6)>;". |
1196 | ||
1197 | FIXME: This case have to be refined correctly: | |
9baba81b SP |
1198 | in some cases it is possible to say something better than |
1199 | chrec_dont_know, for example using a wrap-around notation. */ | |
c59dabbe | 1200 | return t_false; |
9baba81b SP |
1201 | } |
1202 | ||
1203 | /* This function merges the branches of a condition-phi-node in a | |
1204 | loop. */ | |
1205 | ||
c59dabbe | 1206 | static t_bool |
9baba81b | 1207 | follow_ssa_edge_in_condition_phi (struct loop *loop, |
538dd0b7 DM |
1208 | gphi *condition_phi, |
1209 | gphi *halting_phi, | |
c59dabbe | 1210 | tree *evolution_of_loop, int limit) |
9baba81b | 1211 | { |
726a989a | 1212 | int i, n; |
9baba81b SP |
1213 | tree init = *evolution_of_loop; |
1214 | tree evolution_of_branch; | |
c59dabbe SP |
1215 | t_bool res = follow_ssa_edge_in_condition_phi_branch (0, loop, condition_phi, |
1216 | halting_phi, | |
1217 | &evolution_of_branch, | |
1218 | init, limit); | |
1219 | if (res == t_false || res == t_dont_know) | |
1220 | return res; | |
9baba81b | 1221 | |
9baba81b SP |
1222 | *evolution_of_loop = evolution_of_branch; |
1223 | ||
726a989a | 1224 | n = gimple_phi_num_args (condition_phi); |
726a989a | 1225 | for (i = 1; i < n; i++) |
9baba81b | 1226 | { |
e0afb98a SP |
1227 | /* Quickly give up when the evolution of one of the branches is |
1228 | not known. */ | |
1229 | if (*evolution_of_loop == chrec_dont_know) | |
c59dabbe | 1230 | return t_true; |
e0afb98a | 1231 | |
788d3075 RG |
1232 | /* Increase the limit by the PHI argument number to avoid exponential |
1233 | time and memory complexity. */ | |
c59dabbe SP |
1234 | res = follow_ssa_edge_in_condition_phi_branch (i, loop, condition_phi, |
1235 | halting_phi, | |
1236 | &evolution_of_branch, | |
788d3075 | 1237 | init, limit + i); |
c59dabbe SP |
1238 | if (res == t_false || res == t_dont_know) |
1239 | return res; | |
9baba81b SP |
1240 | |
1241 | *evolution_of_loop = chrec_merge (*evolution_of_loop, | |
1242 | evolution_of_branch); | |
1243 | } | |
b8698a0f | 1244 | |
c59dabbe | 1245 | return t_true; |
9baba81b SP |
1246 | } |
1247 | ||
1248 | /* Follow an SSA edge in an inner loop. It computes the overall | |
1249 | effect of the loop, and following the symbolic initial conditions, | |
1250 | it follows the edges in the parent loop. The inner loop is | |
1251 | considered as a single statement. */ | |
1252 | ||
c59dabbe | 1253 | static t_bool |
9baba81b | 1254 | follow_ssa_edge_inner_loop_phi (struct loop *outer_loop, |
538dd0b7 DM |
1255 | gphi *loop_phi_node, |
1256 | gphi *halting_phi, | |
c59dabbe | 1257 | tree *evolution_of_loop, int limit) |
9baba81b SP |
1258 | { |
1259 | struct loop *loop = loop_containing_stmt (loop_phi_node); | |
1260 | tree ev = analyze_scalar_evolution (loop, PHI_RESULT (loop_phi_node)); | |
1261 | ||
1262 | /* Sometimes, the inner loop is too difficult to analyze, and the | |
1263 | result of the analysis is a symbolic parameter. */ | |
1264 | if (ev == PHI_RESULT (loop_phi_node)) | |
1265 | { | |
c59dabbe | 1266 | t_bool res = t_false; |
726a989a | 1267 | int i, n = gimple_phi_num_args (loop_phi_node); |
9baba81b | 1268 | |
726a989a | 1269 | for (i = 0; i < n; i++) |
9baba81b SP |
1270 | { |
1271 | tree arg = PHI_ARG_DEF (loop_phi_node, i); | |
1272 | basic_block bb; | |
1273 | ||
1274 | /* Follow the edges that exit the inner loop. */ | |
726a989a | 1275 | bb = gimple_phi_arg_edge (loop_phi_node, i)->src; |
9baba81b | 1276 | if (!flow_bb_inside_loop_p (loop, bb)) |
726a989a RB |
1277 | res = follow_ssa_edge_expr (outer_loop, loop_phi_node, |
1278 | arg, halting_phi, | |
1279 | evolution_of_loop, limit); | |
c59dabbe SP |
1280 | if (res == t_true) |
1281 | break; | |
9baba81b SP |
1282 | } |
1283 | ||
1284 | /* If the path crosses this loop-phi, give up. */ | |
c59dabbe | 1285 | if (res == t_true) |
9baba81b SP |
1286 | *evolution_of_loop = chrec_dont_know; |
1287 | ||
1288 | return res; | |
1289 | } | |
1290 | ||
1291 | /* Otherwise, compute the overall effect of the inner loop. */ | |
1292 | ev = compute_overall_effect_of_inner_loop (loop, ev); | |
726a989a RB |
1293 | return follow_ssa_edge_expr (outer_loop, loop_phi_node, ev, halting_phi, |
1294 | evolution_of_loop, limit); | |
9baba81b SP |
1295 | } |
1296 | ||
1297 | /* Follow an SSA edge from a loop-phi-node to itself, constructing a | |
1298 | path that is analyzed on the return walk. */ | |
1299 | ||
c59dabbe | 1300 | static t_bool |
355fe088 | 1301 | follow_ssa_edge (struct loop *loop, gimple *def, gphi *halting_phi, |
c59dabbe | 1302 | tree *evolution_of_loop, int limit) |
9baba81b SP |
1303 | { |
1304 | struct loop *def_loop; | |
b8698a0f | 1305 | |
726a989a | 1306 | if (gimple_nop_p (def)) |
c59dabbe | 1307 | return t_false; |
b8698a0f | 1308 | |
c59dabbe | 1309 | /* Give up if the path is longer than the MAX that we allow. */ |
14dd9aab | 1310 | if (limit > PARAM_VALUE (PARAM_SCEV_MAX_EXPR_COMPLEXITY)) |
c59dabbe | 1311 | return t_dont_know; |
b8698a0f | 1312 | |
9baba81b | 1313 | def_loop = loop_containing_stmt (def); |
b8698a0f | 1314 | |
726a989a | 1315 | switch (gimple_code (def)) |
9baba81b | 1316 | { |
726a989a | 1317 | case GIMPLE_PHI: |
9baba81b SP |
1318 | if (!loop_phi_node_p (def)) |
1319 | /* DEF is a condition-phi-node. Follow the branches, and | |
1320 | record their evolutions. Finally, merge the collected | |
1321 | information and set the approximation to the main | |
1322 | variable. */ | |
b8698a0f | 1323 | return follow_ssa_edge_in_condition_phi |
538dd0b7 DM |
1324 | (loop, as_a <gphi *> (def), halting_phi, evolution_of_loop, |
1325 | limit); | |
9baba81b SP |
1326 | |
1327 | /* When the analyzed phi is the halting_phi, the | |
1328 | depth-first search is over: we have found a path from | |
1329 | the halting_phi to itself in the loop. */ | |
1330 | if (def == halting_phi) | |
c59dabbe | 1331 | return t_true; |
b8698a0f | 1332 | |
9baba81b | 1333 | /* Otherwise, the evolution of the HALTING_PHI depends |
89dbed81 | 1334 | on the evolution of another loop-phi-node, i.e. the |
9baba81b SP |
1335 | evolution function is a higher degree polynomial. */ |
1336 | if (def_loop == loop) | |
c59dabbe | 1337 | return t_false; |
b8698a0f | 1338 | |
9baba81b SP |
1339 | /* Inner loop. */ |
1340 | if (flow_loop_nested_p (loop, def_loop)) | |
b8698a0f | 1341 | return follow_ssa_edge_inner_loop_phi |
538dd0b7 DM |
1342 | (loop, as_a <gphi *> (def), halting_phi, evolution_of_loop, |
1343 | limit + 1); | |
9baba81b SP |
1344 | |
1345 | /* Outer loop. */ | |
c59dabbe | 1346 | return t_false; |
9baba81b | 1347 | |
726a989a | 1348 | case GIMPLE_ASSIGN: |
b8698a0f | 1349 | return follow_ssa_edge_in_rhs (loop, def, halting_phi, |
c59dabbe | 1350 | evolution_of_loop, limit); |
b8698a0f | 1351 | |
9baba81b SP |
1352 | default: |
1353 | /* At this level of abstraction, the program is just a set | |
726a989a | 1354 | of GIMPLE_ASSIGNs and PHI_NODEs. In principle there is no |
9baba81b | 1355 | other node to be handled. */ |
c59dabbe | 1356 | return t_false; |
9baba81b SP |
1357 | } |
1358 | } | |
1359 | ||
1360 | \f | |
b83b5507 BC |
1361 | /* Simplify PEELED_CHREC represented by (init_cond, arg) in LOOP. |
1362 | Handle below case and return the corresponding POLYNOMIAL_CHREC: | |
1363 | ||
1364 | # i_17 = PHI <i_13(5), 0(3)> | |
1365 | # _20 = PHI <_5(5), start_4(D)(3)> | |
1366 | ... | |
1367 | i_13 = i_17 + 1; | |
1368 | _5 = start_4(D) + i_13; | |
1369 | ||
1370 | Though variable _20 appears as a PEELED_CHREC in the form of | |
1371 | (start_4, _5)_LOOP, it's a POLYNOMIAL_CHREC like {start_4, 1}_LOOP. | |
1372 | ||
1373 | See PR41488. */ | |
1374 | ||
1375 | static tree | |
1376 | simplify_peeled_chrec (struct loop *loop, tree arg, tree init_cond) | |
1377 | { | |
1378 | aff_tree aff1, aff2; | |
1379 | tree ev, left, right, type, step_val; | |
39c8aaa4 | 1380 | hash_map<tree, name_expansion *> *peeled_chrec_map = NULL; |
b83b5507 BC |
1381 | |
1382 | ev = instantiate_parameters (loop, analyze_scalar_evolution (loop, arg)); | |
1383 | if (ev == NULL_TREE || TREE_CODE (ev) != POLYNOMIAL_CHREC) | |
1384 | return chrec_dont_know; | |
1385 | ||
1386 | left = CHREC_LEFT (ev); | |
1387 | right = CHREC_RIGHT (ev); | |
1388 | type = TREE_TYPE (left); | |
1389 | step_val = chrec_fold_plus (type, init_cond, right); | |
1390 | ||
1391 | /* Transform (init, {left, right}_LOOP)_LOOP to {init, right}_LOOP | |
1392 | if "left" equals to "init + right". */ | |
1393 | if (operand_equal_p (left, step_val, 0)) | |
1394 | { | |
1395 | if (dump_file && (dump_flags & TDF_SCEV)) | |
1396 | fprintf (dump_file, "Simplify PEELED_CHREC into POLYNOMIAL_CHREC.\n"); | |
1397 | ||
1398 | return build_polynomial_chrec (loop->num, init_cond, right); | |
1399 | } | |
1400 | ||
cd5091f1 RB |
1401 | /* The affine code only deals with pointer and integer types. */ |
1402 | if (!POINTER_TYPE_P (type) | |
1403 | && !INTEGRAL_TYPE_P (type)) | |
1404 | return chrec_dont_know; | |
1405 | ||
b83b5507 BC |
1406 | /* Try harder to check if they are equal. */ |
1407 | tree_to_aff_combination_expand (left, type, &aff1, &peeled_chrec_map); | |
1408 | tree_to_aff_combination_expand (step_val, type, &aff2, &peeled_chrec_map); | |
1409 | free_affine_expand_cache (&peeled_chrec_map); | |
807e902e | 1410 | aff_combination_scale (&aff2, -1); |
b83b5507 BC |
1411 | aff_combination_add (&aff1, &aff2); |
1412 | ||
1413 | /* Transform (init, {left, right}_LOOP)_LOOP to {init, right}_LOOP | |
1414 | if "left" equals to "init + right". */ | |
1415 | if (aff_combination_zero_p (&aff1)) | |
1416 | { | |
1417 | if (dump_file && (dump_flags & TDF_SCEV)) | |
1418 | fprintf (dump_file, "Simplify PEELED_CHREC into POLYNOMIAL_CHREC.\n"); | |
1419 | ||
1420 | return build_polynomial_chrec (loop->num, init_cond, right); | |
1421 | } | |
1422 | return chrec_dont_know; | |
1423 | } | |
9baba81b SP |
1424 | |
1425 | /* Given a LOOP_PHI_NODE, this function determines the evolution | |
1426 | function from LOOP_PHI_NODE to LOOP_PHI_NODE in the loop. */ | |
1427 | ||
1428 | static tree | |
538dd0b7 | 1429 | analyze_evolution_in_loop (gphi *loop_phi_node, |
9baba81b SP |
1430 | tree init_cond) |
1431 | { | |
726a989a | 1432 | int i, n = gimple_phi_num_args (loop_phi_node); |
9baba81b SP |
1433 | tree evolution_function = chrec_not_analyzed_yet; |
1434 | struct loop *loop = loop_containing_stmt (loop_phi_node); | |
1435 | basic_block bb; | |
b83b5507 | 1436 | static bool simplify_peeled_chrec_p = true; |
b8698a0f | 1437 | |
dfedbe40 | 1438 | if (dump_file && (dump_flags & TDF_SCEV)) |
9baba81b SP |
1439 | { |
1440 | fprintf (dump_file, "(analyze_evolution_in_loop \n"); | |
1441 | fprintf (dump_file, " (loop_phi_node = "); | |
ef6cb4c7 | 1442 | print_gimple_stmt (dump_file, loop_phi_node, 0); |
9baba81b SP |
1443 | fprintf (dump_file, ")\n"); |
1444 | } | |
b8698a0f | 1445 | |
726a989a | 1446 | for (i = 0; i < n; i++) |
9baba81b SP |
1447 | { |
1448 | tree arg = PHI_ARG_DEF (loop_phi_node, i); | |
355fe088 | 1449 | gimple *ssa_chain; |
726a989a | 1450 | tree ev_fn; |
874caa00 | 1451 | t_bool res; |
9baba81b SP |
1452 | |
1453 | /* Select the edges that enter the loop body. */ | |
726a989a | 1454 | bb = gimple_phi_arg_edge (loop_phi_node, i)->src; |
9baba81b SP |
1455 | if (!flow_bb_inside_loop_p (loop, bb)) |
1456 | continue; | |
f29deac9 | 1457 | |
9baba81b SP |
1458 | if (TREE_CODE (arg) == SSA_NAME) |
1459 | { | |
f29deac9 SP |
1460 | bool val = false; |
1461 | ||
9baba81b SP |
1462 | ssa_chain = SSA_NAME_DEF_STMT (arg); |
1463 | ||
1464 | /* Pass in the initial condition to the follow edge function. */ | |
1465 | ev_fn = init_cond; | |
c59dabbe | 1466 | res = follow_ssa_edge (loop, ssa_chain, loop_phi_node, &ev_fn, 0); |
f29deac9 SP |
1467 | |
1468 | /* If ev_fn has no evolution in the inner loop, and the | |
1469 | init_cond is not equal to ev_fn, then we have an | |
1470 | ambiguity between two possible values, as we cannot know | |
1471 | the number of iterations at this point. */ | |
1472 | if (TREE_CODE (ev_fn) != POLYNOMIAL_CHREC | |
1473 | && no_evolution_in_loop_p (ev_fn, loop->num, &val) && val | |
1474 | && !operand_equal_p (init_cond, ev_fn, 0)) | |
1475 | ev_fn = chrec_dont_know; | |
9baba81b SP |
1476 | } |
1477 | else | |
874caa00 | 1478 | res = t_false; |
f29deac9 | 1479 | |
9baba81b SP |
1480 | /* When it is impossible to go back on the same |
1481 | loop_phi_node by following the ssa edges, the | |
89dbed81 | 1482 | evolution is represented by a peeled chrec, i.e. the |
9baba81b | 1483 | first iteration, EV_FN has the value INIT_COND, then |
b8698a0f | 1484 | all the other iterations it has the value of ARG. |
9baba81b | 1485 | For the moment, PEELED_CHREC nodes are not built. */ |
874caa00 | 1486 | if (res != t_true) |
b83b5507 BC |
1487 | { |
1488 | ev_fn = chrec_dont_know; | |
1489 | /* Try to recognize POLYNOMIAL_CHREC which appears in | |
1490 | the form of PEELED_CHREC, but guard the process with | |
1491 | a bool variable to keep the analyzer from infinite | |
1492 | recurrence for real PEELED_RECs. */ | |
1493 | if (simplify_peeled_chrec_p && TREE_CODE (arg) == SSA_NAME) | |
1494 | { | |
1495 | simplify_peeled_chrec_p = false; | |
1496 | ev_fn = simplify_peeled_chrec (loop, arg, init_cond); | |
1497 | simplify_peeled_chrec_p = true; | |
1498 | } | |
1499 | } | |
b8698a0f | 1500 | |
9baba81b | 1501 | /* When there are multiple back edges of the loop (which in fact never |
8c27b7d4 | 1502 | happens currently, but nevertheless), merge their evolutions. */ |
9baba81b | 1503 | evolution_function = chrec_merge (evolution_function, ev_fn); |
e21401b6 RB |
1504 | |
1505 | if (evolution_function == chrec_dont_know) | |
1506 | break; | |
9baba81b | 1507 | } |
b8698a0f | 1508 | |
dfedbe40 | 1509 | if (dump_file && (dump_flags & TDF_SCEV)) |
9baba81b SP |
1510 | { |
1511 | fprintf (dump_file, " (evolution_function = "); | |
ef6cb4c7 | 1512 | print_generic_expr (dump_file, evolution_function); |
9baba81b SP |
1513 | fprintf (dump_file, "))\n"); |
1514 | } | |
b8698a0f | 1515 | |
9baba81b SP |
1516 | return evolution_function; |
1517 | } | |
1518 | ||
806f2c1b AL |
1519 | /* Looks to see if VAR is a copy of a constant (via straightforward assignments |
1520 | or degenerate phi's). If so, returns the constant; else, returns VAR. */ | |
1521 | ||
1522 | static tree | |
1523 | follow_copies_to_constant (tree var) | |
1524 | { | |
1525 | tree res = var; | |
24545562 RB |
1526 | while (TREE_CODE (res) == SSA_NAME |
1527 | /* We face not updated SSA form in multiple places and this walk | |
1528 | may end up in sibling loops so we have to guard it. */ | |
1529 | && !name_registered_for_update_p (res)) | |
806f2c1b AL |
1530 | { |
1531 | gimple *def = SSA_NAME_DEF_STMT (res); | |
1532 | if (gphi *phi = dyn_cast <gphi *> (def)) | |
1533 | { | |
1534 | if (tree rhs = degenerate_phi_result (phi)) | |
1535 | res = rhs; | |
1536 | else | |
1537 | break; | |
1538 | } | |
1539 | else if (gimple_assign_single_p (def)) | |
1540 | /* Will exit loop if not an SSA_NAME. */ | |
1541 | res = gimple_assign_rhs1 (def); | |
1542 | else | |
1543 | break; | |
1544 | } | |
1545 | if (CONSTANT_CLASS_P (res)) | |
1546 | return res; | |
1547 | return var; | |
1548 | } | |
1549 | ||
9baba81b SP |
1550 | /* Given a loop-phi-node, return the initial conditions of the |
1551 | variable on entry of the loop. When the CCP has propagated | |
1552 | constants into the loop-phi-node, the initial condition is | |
1553 | instantiated, otherwise the initial condition is kept symbolic. | |
1554 | This analyzer does not analyze the evolution outside the current | |
1555 | loop, and leaves this task to the on-demand tree reconstructor. */ | |
1556 | ||
b8698a0f | 1557 | static tree |
538dd0b7 | 1558 | analyze_initial_condition (gphi *loop_phi_node) |
9baba81b | 1559 | { |
726a989a | 1560 | int i, n; |
9baba81b | 1561 | tree init_cond = chrec_not_analyzed_yet; |
726a989a | 1562 | struct loop *loop = loop_containing_stmt (loop_phi_node); |
b8698a0f | 1563 | |
dfedbe40 | 1564 | if (dump_file && (dump_flags & TDF_SCEV)) |
9baba81b SP |
1565 | { |
1566 | fprintf (dump_file, "(analyze_initial_condition \n"); | |
1567 | fprintf (dump_file, " (loop_phi_node = \n"); | |
ef6cb4c7 | 1568 | print_gimple_stmt (dump_file, loop_phi_node, 0); |
9baba81b SP |
1569 | fprintf (dump_file, ")\n"); |
1570 | } | |
b8698a0f | 1571 | |
726a989a RB |
1572 | n = gimple_phi_num_args (loop_phi_node); |
1573 | for (i = 0; i < n; i++) | |
9baba81b SP |
1574 | { |
1575 | tree branch = PHI_ARG_DEF (loop_phi_node, i); | |
726a989a | 1576 | basic_block bb = gimple_phi_arg_edge (loop_phi_node, i)->src; |
b8698a0f | 1577 | |
9baba81b SP |
1578 | /* When the branch is oriented to the loop's body, it does |
1579 | not contribute to the initial condition. */ | |
1580 | if (flow_bb_inside_loop_p (loop, bb)) | |
1581 | continue; | |
1582 | ||
1583 | if (init_cond == chrec_not_analyzed_yet) | |
1584 | { | |
1585 | init_cond = branch; | |
1586 | continue; | |
1587 | } | |
1588 | ||
1589 | if (TREE_CODE (branch) == SSA_NAME) | |
1590 | { | |
1591 | init_cond = chrec_dont_know; | |
1592 | break; | |
1593 | } | |
1594 | ||
1595 | init_cond = chrec_merge (init_cond, branch); | |
1596 | } | |
1597 | ||
1598 | /* Ooops -- a loop without an entry??? */ | |
1599 | if (init_cond == chrec_not_analyzed_yet) | |
1600 | init_cond = chrec_dont_know; | |
1601 | ||
806f2c1b AL |
1602 | /* We may not have fully constant propagated IL. Handle degenerate PHIs here |
1603 | to not miss important early loop unrollings. */ | |
1604 | init_cond = follow_copies_to_constant (init_cond); | |
bf1cbdc6 | 1605 | |
dfedbe40 | 1606 | if (dump_file && (dump_flags & TDF_SCEV)) |
9baba81b SP |
1607 | { |
1608 | fprintf (dump_file, " (init_cond = "); | |
ef6cb4c7 | 1609 | print_generic_expr (dump_file, init_cond); |
9baba81b SP |
1610 | fprintf (dump_file, "))\n"); |
1611 | } | |
b8698a0f | 1612 | |
9baba81b SP |
1613 | return init_cond; |
1614 | } | |
1615 | ||
1616 | /* Analyze the scalar evolution for LOOP_PHI_NODE. */ | |
1617 | ||
b8698a0f | 1618 | static tree |
538dd0b7 | 1619 | interpret_loop_phi (struct loop *loop, gphi *loop_phi_node) |
9baba81b SP |
1620 | { |
1621 | tree res; | |
1622 | struct loop *phi_loop = loop_containing_stmt (loop_phi_node); | |
1623 | tree init_cond; | |
b8698a0f | 1624 | |
5355943c | 1625 | gcc_assert (phi_loop == loop); |
9baba81b SP |
1626 | |
1627 | /* Otherwise really interpret the loop phi. */ | |
1628 | init_cond = analyze_initial_condition (loop_phi_node); | |
1629 | res = analyze_evolution_in_loop (loop_phi_node, init_cond); | |
1630 | ||
73c865fa RG |
1631 | /* Verify we maintained the correct initial condition throughout |
1632 | possible conversions in the SSA chain. */ | |
1633 | if (res != chrec_dont_know) | |
1634 | { | |
1635 | tree new_init = res; | |
1636 | if (CONVERT_EXPR_P (res) | |
1637 | && TREE_CODE (TREE_OPERAND (res, 0)) == POLYNOMIAL_CHREC) | |
1638 | new_init = fold_convert (TREE_TYPE (res), | |
1639 | CHREC_LEFT (TREE_OPERAND (res, 0))); | |
1640 | else if (TREE_CODE (res) == POLYNOMIAL_CHREC) | |
1641 | new_init = CHREC_LEFT (res); | |
1642 | STRIP_USELESS_TYPE_CONVERSION (new_init); | |
eb723fa3 RG |
1643 | if (TREE_CODE (new_init) == POLYNOMIAL_CHREC |
1644 | || !operand_equal_p (init_cond, new_init, 0)) | |
73c865fa RG |
1645 | return chrec_dont_know; |
1646 | } | |
1647 | ||
9baba81b SP |
1648 | return res; |
1649 | } | |
1650 | ||
1651 | /* This function merges the branches of a condition-phi-node, | |
1652 | contained in the outermost loop, and whose arguments are already | |
1653 | analyzed. */ | |
1654 | ||
1655 | static tree | |
538dd0b7 | 1656 | interpret_condition_phi (struct loop *loop, gphi *condition_phi) |
9baba81b | 1657 | { |
726a989a | 1658 | int i, n = gimple_phi_num_args (condition_phi); |
9baba81b | 1659 | tree res = chrec_not_analyzed_yet; |
b8698a0f | 1660 | |
726a989a | 1661 | for (i = 0; i < n; i++) |
9baba81b SP |
1662 | { |
1663 | tree branch_chrec; | |
b8698a0f | 1664 | |
9baba81b SP |
1665 | if (backedge_phi_arg_p (condition_phi, i)) |
1666 | { | |
1667 | res = chrec_dont_know; | |
1668 | break; | |
1669 | } | |
1670 | ||
1671 | branch_chrec = analyze_scalar_evolution | |
1672 | (loop, PHI_ARG_DEF (condition_phi, i)); | |
b8698a0f | 1673 | |
9baba81b | 1674 | res = chrec_merge (res, branch_chrec); |
e21401b6 RB |
1675 | if (res == chrec_dont_know) |
1676 | break; | |
9baba81b SP |
1677 | } |
1678 | ||
1679 | return res; | |
1680 | } | |
1681 | ||
726a989a | 1682 | /* Interpret the operation RHS1 OP RHS2. If we didn't |
29836d07 | 1683 | analyze this node before, follow the definitions until ending |
726a989a | 1684 | either on an analyzed GIMPLE_ASSIGN, or on a loop-phi-node. On the |
9baba81b SP |
1685 | return path, this function propagates evolutions (ala constant copy |
1686 | propagation). OPND1 is not a GIMPLE expression because we could | |
1687 | analyze the effect of an inner loop: see interpret_loop_phi. */ | |
1688 | ||
1689 | static tree | |
355fe088 | 1690 | interpret_rhs_expr (struct loop *loop, gimple *at_stmt, |
726a989a | 1691 | tree type, tree rhs1, enum tree_code code, tree rhs2) |
9baba81b | 1692 | { |
f802a424 | 1693 | tree res, chrec1, chrec2, ctype; |
355fe088 | 1694 | gimple *def; |
726a989a RB |
1695 | |
1696 | if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS) | |
1697 | { | |
1698 | if (is_gimple_min_invariant (rhs1)) | |
1699 | return chrec_convert (type, rhs1, at_stmt); | |
1700 | ||
1701 | if (code == SSA_NAME) | |
1702 | return chrec_convert (type, analyze_scalar_evolution (loop, rhs1), | |
1703 | at_stmt); | |
1e8552eb | 1704 | |
726a989a RB |
1705 | if (code == ASSERT_EXPR) |
1706 | { | |
1707 | rhs1 = ASSERT_EXPR_VAR (rhs1); | |
1708 | return chrec_convert (type, analyze_scalar_evolution (loop, rhs1), | |
1709 | at_stmt); | |
1710 | } | |
726a989a | 1711 | } |
1e8552eb | 1712 | |
726a989a | 1713 | switch (code) |
9baba81b | 1714 | { |
6a02a719 | 1715 | case ADDR_EXPR: |
bef28ced JL |
1716 | if (TREE_CODE (TREE_OPERAND (rhs1, 0)) == MEM_REF |
1717 | || handled_component_p (TREE_OPERAND (rhs1, 0))) | |
1718 | { | |
ef4bddc2 | 1719 | machine_mode mode; |
f37fac2b | 1720 | poly_int64 bitsize, bitpos; |
ee45a32d | 1721 | int unsignedp, reversep; |
bef28ced JL |
1722 | int volatilep = 0; |
1723 | tree base, offset; | |
1724 | tree chrec3; | |
1725 | tree unitpos; | |
1726 | ||
1727 | base = get_inner_reference (TREE_OPERAND (rhs1, 0), | |
ee45a32d | 1728 | &bitsize, &bitpos, &offset, &mode, |
25b75a48 | 1729 | &unsignedp, &reversep, &volatilep); |
bef28ced JL |
1730 | |
1731 | if (TREE_CODE (base) == MEM_REF) | |
1732 | { | |
1733 | rhs2 = TREE_OPERAND (base, 1); | |
1734 | rhs1 = TREE_OPERAND (base, 0); | |
1735 | ||
1736 | chrec1 = analyze_scalar_evolution (loop, rhs1); | |
1737 | chrec2 = analyze_scalar_evolution (loop, rhs2); | |
1738 | chrec1 = chrec_convert (type, chrec1, at_stmt); | |
1739 | chrec2 = chrec_convert (TREE_TYPE (rhs2), chrec2, at_stmt); | |
0547c9b6 RB |
1740 | chrec1 = instantiate_parameters (loop, chrec1); |
1741 | chrec2 = instantiate_parameters (loop, chrec2); | |
bef28ced JL |
1742 | res = chrec_fold_plus (type, chrec1, chrec2); |
1743 | } | |
1744 | else | |
1745 | { | |
1746 | chrec1 = analyze_scalar_evolution_for_address_of (loop, base); | |
1747 | chrec1 = chrec_convert (type, chrec1, at_stmt); | |
1748 | res = chrec1; | |
1749 | } | |
6a02a719 | 1750 | |
bef28ced JL |
1751 | if (offset != NULL_TREE) |
1752 | { | |
1753 | chrec2 = analyze_scalar_evolution (loop, offset); | |
1754 | chrec2 = chrec_convert (TREE_TYPE (offset), chrec2, at_stmt); | |
0547c9b6 | 1755 | chrec2 = instantiate_parameters (loop, chrec2); |
bef28ced JL |
1756 | res = chrec_fold_plus (type, res, chrec2); |
1757 | } | |
1758 | ||
f37fac2b | 1759 | if (maybe_ne (bitpos, 0)) |
bef28ced | 1760 | { |
f37fac2b | 1761 | unitpos = size_int (exact_div (bitpos, BITS_PER_UNIT)); |
bef28ced JL |
1762 | chrec3 = analyze_scalar_evolution (loop, unitpos); |
1763 | chrec3 = chrec_convert (TREE_TYPE (unitpos), chrec3, at_stmt); | |
0547c9b6 | 1764 | chrec3 = instantiate_parameters (loop, chrec3); |
bef28ced JL |
1765 | res = chrec_fold_plus (type, res, chrec3); |
1766 | } | |
1767 | } | |
1768 | else | |
1769 | res = chrec_dont_know; | |
1770 | break; | |
6a02a719 | 1771 | |
5be014d5 | 1772 | case POINTER_PLUS_EXPR: |
726a989a RB |
1773 | chrec1 = analyze_scalar_evolution (loop, rhs1); |
1774 | chrec2 = analyze_scalar_evolution (loop, rhs2); | |
1775 | chrec1 = chrec_convert (type, chrec1, at_stmt); | |
0d82a1c8 | 1776 | chrec2 = chrec_convert (TREE_TYPE (rhs2), chrec2, at_stmt); |
0547c9b6 RB |
1777 | chrec1 = instantiate_parameters (loop, chrec1); |
1778 | chrec2 = instantiate_parameters (loop, chrec2); | |
726a989a | 1779 | res = chrec_fold_plus (type, chrec1, chrec2); |
5be014d5 AP |
1780 | break; |
1781 | ||
9baba81b | 1782 | case PLUS_EXPR: |
726a989a RB |
1783 | chrec1 = analyze_scalar_evolution (loop, rhs1); |
1784 | chrec2 = analyze_scalar_evolution (loop, rhs2); | |
f802a424 RB |
1785 | ctype = type; |
1786 | /* When the stmt is conditionally executed re-write the CHREC | |
1787 | into a form that has well-defined behavior on overflow. */ | |
1788 | if (at_stmt | |
1789 | && INTEGRAL_TYPE_P (type) | |
1790 | && ! TYPE_OVERFLOW_WRAPS (type) | |
1791 | && ! dominated_by_p (CDI_DOMINATORS, loop->latch, | |
1792 | gimple_bb (at_stmt))) | |
1793 | ctype = unsigned_type_for (type); | |
1794 | chrec1 = chrec_convert (ctype, chrec1, at_stmt); | |
1795 | chrec2 = chrec_convert (ctype, chrec2, at_stmt); | |
0547c9b6 RB |
1796 | chrec1 = instantiate_parameters (loop, chrec1); |
1797 | chrec2 = instantiate_parameters (loop, chrec2); | |
f802a424 RB |
1798 | res = chrec_fold_plus (ctype, chrec1, chrec2); |
1799 | if (type != ctype) | |
1800 | res = chrec_convert (type, res, at_stmt); | |
9baba81b | 1801 | break; |
b8698a0f | 1802 | |
9baba81b | 1803 | case MINUS_EXPR: |
726a989a RB |
1804 | chrec1 = analyze_scalar_evolution (loop, rhs1); |
1805 | chrec2 = analyze_scalar_evolution (loop, rhs2); | |
f802a424 RB |
1806 | ctype = type; |
1807 | /* When the stmt is conditionally executed re-write the CHREC | |
1808 | into a form that has well-defined behavior on overflow. */ | |
1809 | if (at_stmt | |
1810 | && INTEGRAL_TYPE_P (type) | |
1811 | && ! TYPE_OVERFLOW_WRAPS (type) | |
1812 | && ! dominated_by_p (CDI_DOMINATORS, | |
1813 | loop->latch, gimple_bb (at_stmt))) | |
1814 | ctype = unsigned_type_for (type); | |
1815 | chrec1 = chrec_convert (ctype, chrec1, at_stmt); | |
1816 | chrec2 = chrec_convert (ctype, chrec2, at_stmt); | |
0547c9b6 RB |
1817 | chrec1 = instantiate_parameters (loop, chrec1); |
1818 | chrec2 = instantiate_parameters (loop, chrec2); | |
f802a424 RB |
1819 | res = chrec_fold_minus (ctype, chrec1, chrec2); |
1820 | if (type != ctype) | |
1821 | res = chrec_convert (type, res, at_stmt); | |
9baba81b SP |
1822 | break; |
1823 | ||
1824 | case NEGATE_EXPR: | |
726a989a | 1825 | chrec1 = analyze_scalar_evolution (loop, rhs1); |
f802a424 RB |
1826 | ctype = type; |
1827 | /* When the stmt is conditionally executed re-write the CHREC | |
1828 | into a form that has well-defined behavior on overflow. */ | |
1829 | if (at_stmt | |
1830 | && INTEGRAL_TYPE_P (type) | |
1831 | && ! TYPE_OVERFLOW_WRAPS (type) | |
1832 | && ! dominated_by_p (CDI_DOMINATORS, | |
1833 | loop->latch, gimple_bb (at_stmt))) | |
1834 | ctype = unsigned_type_for (type); | |
1835 | chrec1 = chrec_convert (ctype, chrec1, at_stmt); | |
9a75ede0 | 1836 | /* TYPE may be integer, real or complex, so use fold_convert. */ |
0547c9b6 | 1837 | chrec1 = instantiate_parameters (loop, chrec1); |
f802a424 RB |
1838 | res = chrec_fold_multiply (ctype, chrec1, |
1839 | fold_convert (ctype, integer_minus_one_node)); | |
1840 | if (type != ctype) | |
1841 | res = chrec_convert (type, res, at_stmt); | |
9baba81b SP |
1842 | break; |
1843 | ||
418df9d7 JJ |
1844 | case BIT_NOT_EXPR: |
1845 | /* Handle ~X as -1 - X. */ | |
1846 | chrec1 = analyze_scalar_evolution (loop, rhs1); | |
1847 | chrec1 = chrec_convert (type, chrec1, at_stmt); | |
0547c9b6 | 1848 | chrec1 = instantiate_parameters (loop, chrec1); |
418df9d7 JJ |
1849 | res = chrec_fold_minus (type, |
1850 | fold_convert (type, integer_minus_one_node), | |
1851 | chrec1); | |
1852 | break; | |
1853 | ||
9baba81b | 1854 | case MULT_EXPR: |
726a989a RB |
1855 | chrec1 = analyze_scalar_evolution (loop, rhs1); |
1856 | chrec2 = analyze_scalar_evolution (loop, rhs2); | |
f802a424 RB |
1857 | ctype = type; |
1858 | /* When the stmt is conditionally executed re-write the CHREC | |
1859 | into a form that has well-defined behavior on overflow. */ | |
1860 | if (at_stmt | |
1861 | && INTEGRAL_TYPE_P (type) | |
1862 | && ! TYPE_OVERFLOW_WRAPS (type) | |
1863 | && ! dominated_by_p (CDI_DOMINATORS, | |
1864 | loop->latch, gimple_bb (at_stmt))) | |
1865 | ctype = unsigned_type_for (type); | |
1866 | chrec1 = chrec_convert (ctype, chrec1, at_stmt); | |
1867 | chrec2 = chrec_convert (ctype, chrec2, at_stmt); | |
0547c9b6 RB |
1868 | chrec1 = instantiate_parameters (loop, chrec1); |
1869 | chrec2 = instantiate_parameters (loop, chrec2); | |
f802a424 RB |
1870 | res = chrec_fold_multiply (ctype, chrec1, chrec2); |
1871 | if (type != ctype) | |
1872 | res = chrec_convert (type, res, at_stmt); | |
0bca51f0 | 1873 | break; |
b8698a0f | 1874 | |
60f2d2f3 AL |
1875 | case LSHIFT_EXPR: |
1876 | { | |
1877 | /* Handle A<<B as A * (1<<B). */ | |
1878 | tree uns = unsigned_type_for (type); | |
1879 | chrec1 = analyze_scalar_evolution (loop, rhs1); | |
1880 | chrec2 = analyze_scalar_evolution (loop, rhs2); | |
1881 | chrec1 = chrec_convert (uns, chrec1, at_stmt); | |
1882 | chrec1 = instantiate_parameters (loop, chrec1); | |
1883 | chrec2 = instantiate_parameters (loop, chrec2); | |
1884 | ||
1885 | tree one = build_int_cst (uns, 1); | |
1886 | chrec2 = fold_build2 (LSHIFT_EXPR, uns, one, chrec2); | |
1887 | res = chrec_fold_multiply (uns, chrec1, chrec2); | |
1888 | res = chrec_convert (type, res, at_stmt); | |
1889 | } | |
1890 | break; | |
1891 | ||
1043771b | 1892 | CASE_CONVERT: |
195b4c50 RG |
1893 | /* In case we have a truncation of a widened operation that in |
1894 | the truncated type has undefined overflow behavior analyze | |
1895 | the operation done in an unsigned type of the same precision | |
1896 | as the final truncation. We cannot derive a scalar evolution | |
1897 | for the widened operation but for the truncated result. */ | |
1898 | if (TREE_CODE (type) == INTEGER_TYPE | |
1899 | && TREE_CODE (TREE_TYPE (rhs1)) == INTEGER_TYPE | |
1900 | && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (rhs1)) | |
1901 | && TYPE_OVERFLOW_UNDEFINED (type) | |
1902 | && TREE_CODE (rhs1) == SSA_NAME | |
1903 | && (def = SSA_NAME_DEF_STMT (rhs1)) | |
1904 | && is_gimple_assign (def) | |
1905 | && TREE_CODE_CLASS (gimple_assign_rhs_code (def)) == tcc_binary | |
1906 | && TREE_CODE (gimple_assign_rhs2 (def)) == INTEGER_CST) | |
1907 | { | |
1908 | tree utype = unsigned_type_for (type); | |
1909 | chrec1 = interpret_rhs_expr (loop, at_stmt, utype, | |
1910 | gimple_assign_rhs1 (def), | |
1911 | gimple_assign_rhs_code (def), | |
1912 | gimple_assign_rhs2 (def)); | |
1913 | } | |
1914 | else | |
1915 | chrec1 = analyze_scalar_evolution (loop, rhs1); | |
b24d9420 | 1916 | res = chrec_convert (type, chrec1, at_stmt, true, rhs1); |
9baba81b | 1917 | break; |
e6d62b46 BC |
1918 | |
1919 | case BIT_AND_EXPR: | |
1920 | /* Given int variable A, handle A&0xffff as (int)(unsigned short)A. | |
1921 | If A is SCEV and its value is in the range of representable set | |
1922 | of type unsigned short, the result expression is a (no-overflow) | |
1923 | SCEV. */ | |
1924 | res = chrec_dont_know; | |
1925 | if (tree_fits_uhwi_p (rhs2)) | |
1926 | { | |
1927 | int precision; | |
1928 | unsigned HOST_WIDE_INT val = tree_to_uhwi (rhs2); | |
1929 | ||
1930 | val ++; | |
1931 | /* Skip if value of rhs2 wraps in unsigned HOST_WIDE_INT or | |
1932 | it's not the maximum value of a smaller type than rhs1. */ | |
1933 | if (val != 0 | |
1934 | && (precision = exact_log2 (val)) > 0 | |
1935 | && (unsigned) precision < TYPE_PRECISION (TREE_TYPE (rhs1))) | |
1936 | { | |
1937 | tree utype = build_nonstandard_integer_type (precision, 1); | |
1938 | ||
1939 | if (TYPE_PRECISION (utype) < TYPE_PRECISION (TREE_TYPE (rhs1))) | |
1940 | { | |
1941 | chrec1 = analyze_scalar_evolution (loop, rhs1); | |
1942 | chrec1 = chrec_convert (utype, chrec1, at_stmt); | |
1943 | res = chrec_convert (TREE_TYPE (rhs1), chrec1, at_stmt); | |
1944 | } | |
1945 | } | |
1946 | } | |
1947 | break; | |
b8698a0f | 1948 | |
9baba81b SP |
1949 | default: |
1950 | res = chrec_dont_know; | |
1951 | break; | |
1952 | } | |
b8698a0f | 1953 | |
9baba81b SP |
1954 | return res; |
1955 | } | |
1956 | ||
726a989a RB |
1957 | /* Interpret the expression EXPR. */ |
1958 | ||
1959 | static tree | |
355fe088 | 1960 | interpret_expr (struct loop *loop, gimple *at_stmt, tree expr) |
726a989a RB |
1961 | { |
1962 | enum tree_code code; | |
1963 | tree type = TREE_TYPE (expr), op0, op1; | |
1964 | ||
1965 | if (automatically_generated_chrec_p (expr)) | |
1966 | return expr; | |
1967 | ||
4e71066d | 1968 | if (TREE_CODE (expr) == POLYNOMIAL_CHREC |
5126ae0c | 1969 | || TREE_CODE (expr) == CALL_EXPR |
4e71066d | 1970 | || get_gimple_rhs_class (TREE_CODE (expr)) == GIMPLE_TERNARY_RHS) |
726a989a RB |
1971 | return chrec_dont_know; |
1972 | ||
1973 | extract_ops_from_tree (expr, &code, &op0, &op1); | |
1974 | ||
1975 | return interpret_rhs_expr (loop, at_stmt, type, | |
1976 | op0, code, op1); | |
1977 | } | |
1978 | ||
1979 | /* Interpret the rhs of the assignment STMT. */ | |
1980 | ||
1981 | static tree | |
355fe088 | 1982 | interpret_gimple_assign (struct loop *loop, gimple *stmt) |
726a989a RB |
1983 | { |
1984 | tree type = TREE_TYPE (gimple_assign_lhs (stmt)); | |
1985 | enum tree_code code = gimple_assign_rhs_code (stmt); | |
1986 | ||
1987 | return interpret_rhs_expr (loop, stmt, type, | |
1988 | gimple_assign_rhs1 (stmt), code, | |
1989 | gimple_assign_rhs2 (stmt)); | |
1990 | } | |
1991 | ||
9baba81b SP |
1992 | \f |
1993 | ||
b8698a0f | 1994 | /* This section contains all the entry points: |
9baba81b SP |
1995 | - number_of_iterations_in_loop, |
1996 | - analyze_scalar_evolution, | |
1997 | - instantiate_parameters. | |
1998 | */ | |
1999 | ||
9baba81b SP |
2000 | /* Helper recursive function. */ |
2001 | ||
2002 | static tree | |
fb1fe1f3 | 2003 | analyze_scalar_evolution_1 (struct loop *loop, tree var) |
9baba81b | 2004 | { |
355fe088 | 2005 | gimple *def; |
9baba81b SP |
2006 | basic_block bb; |
2007 | struct loop *def_loop; | |
fb1fe1f3 | 2008 | tree res; |
9baba81b | 2009 | |
9baba81b | 2010 | if (TREE_CODE (var) != SSA_NAME) |
726a989a | 2011 | return interpret_expr (loop, NULL, var); |
9baba81b SP |
2012 | |
2013 | def = SSA_NAME_DEF_STMT (var); | |
726a989a | 2014 | bb = gimple_bb (def); |
5355943c | 2015 | def_loop = bb->loop_father; |
9baba81b | 2016 | |
5355943c | 2017 | if (!flow_bb_inside_loop_p (loop, bb)) |
9baba81b | 2018 | { |
806f2c1b AL |
2019 | /* Keep symbolic form, but look through obvious copies for constants. */ |
2020 | res = follow_copies_to_constant (var); | |
9baba81b SP |
2021 | goto set_and_end; |
2022 | } | |
2023 | ||
9baba81b SP |
2024 | if (loop != def_loop) |
2025 | { | |
fb1fe1f3 | 2026 | res = analyze_scalar_evolution_1 (def_loop, var); |
5355943c RB |
2027 | struct loop *loop_to_skip = superloop_at_depth (def_loop, |
2028 | loop_depth (loop) + 1); | |
2029 | res = compute_overall_effect_of_inner_loop (loop_to_skip, res); | |
2030 | if (chrec_contains_symbols_defined_in_loop (res, loop->num)) | |
2031 | res = analyze_scalar_evolution_1 (loop, res); | |
9baba81b SP |
2032 | goto set_and_end; |
2033 | } | |
2034 | ||
726a989a | 2035 | switch (gimple_code (def)) |
9baba81b | 2036 | { |
726a989a RB |
2037 | case GIMPLE_ASSIGN: |
2038 | res = interpret_gimple_assign (loop, def); | |
9baba81b SP |
2039 | break; |
2040 | ||
726a989a | 2041 | case GIMPLE_PHI: |
9baba81b | 2042 | if (loop_phi_node_p (def)) |
538dd0b7 | 2043 | res = interpret_loop_phi (loop, as_a <gphi *> (def)); |
9baba81b | 2044 | else |
538dd0b7 | 2045 | res = interpret_condition_phi (loop, as_a <gphi *> (def)); |
9baba81b SP |
2046 | break; |
2047 | ||
2048 | default: | |
2049 | res = chrec_dont_know; | |
2050 | break; | |
2051 | } | |
2052 | ||
2053 | set_and_end: | |
2054 | ||
2055 | /* Keep the symbolic form. */ | |
2056 | if (res == chrec_dont_know) | |
2057 | res = var; | |
2058 | ||
2059 | if (loop == def_loop) | |
a213b219 | 2060 | set_scalar_evolution (block_before_loop (loop), var, res); |
9baba81b SP |
2061 | |
2062 | return res; | |
2063 | } | |
2064 | ||
52bdd655 SP |
2065 | /* Analyzes and returns the scalar evolution of the ssa_name VAR in |
2066 | LOOP. LOOP is the loop in which the variable is used. | |
b8698a0f | 2067 | |
9baba81b SP |
2068 | Example of use: having a pointer VAR to a SSA_NAME node, STMT a |
2069 | pointer to the statement that uses this variable, in order to | |
2070 | determine the evolution function of the variable, use the following | |
2071 | calls: | |
b8698a0f | 2072 | |
52bdd655 SP |
2073 | loop_p loop = loop_containing_stmt (stmt); |
2074 | tree chrec_with_symbols = analyze_scalar_evolution (loop, var); | |
3f227a8c | 2075 | tree chrec_instantiated = instantiate_parameters (loop, chrec_with_symbols); |
9baba81b SP |
2076 | */ |
2077 | ||
b8698a0f | 2078 | tree |
9baba81b SP |
2079 | analyze_scalar_evolution (struct loop *loop, tree var) |
2080 | { | |
2081 | tree res; | |
2082 | ||
a68f286c RB |
2083 | /* ??? Fix callers. */ |
2084 | if (! loop) | |
2085 | return var; | |
2086 | ||
dfedbe40 | 2087 | if (dump_file && (dump_flags & TDF_SCEV)) |
9baba81b SP |
2088 | { |
2089 | fprintf (dump_file, "(analyze_scalar_evolution \n"); | |
2090 | fprintf (dump_file, " (loop_nb = %d)\n", loop->num); | |
2091 | fprintf (dump_file, " (scalar = "); | |
ef6cb4c7 | 2092 | print_generic_expr (dump_file, var); |
9baba81b SP |
2093 | fprintf (dump_file, ")\n"); |
2094 | } | |
2095 | ||
a213b219 | 2096 | res = get_scalar_evolution (block_before_loop (loop), var); |
fb1fe1f3 | 2097 | if (res == chrec_not_analyzed_yet) |
577d6588 RB |
2098 | { |
2099 | /* We'll recurse into instantiate_scev, avoid tearing down the | |
2100 | instantiate cache repeatedly and keep it live from here. */ | |
2101 | bool destr = false; | |
2102 | if (!global_cache) | |
2103 | { | |
2104 | global_cache = new instantiate_cache_type; | |
2105 | destr = true; | |
2106 | } | |
2107 | res = analyze_scalar_evolution_1 (loop, var); | |
2108 | if (destr) | |
2109 | { | |
2110 | delete global_cache; | |
2111 | global_cache = NULL; | |
2112 | } | |
2113 | } | |
9baba81b | 2114 | |
dfedbe40 | 2115 | if (dump_file && (dump_flags & TDF_SCEV)) |
9baba81b SP |
2116 | fprintf (dump_file, ")\n"); |
2117 | ||
2118 | return res; | |
2119 | } | |
2120 | ||
bef28ced JL |
2121 | /* Analyzes and returns the scalar evolution of VAR address in LOOP. */ |
2122 | ||
2123 | static tree | |
2124 | analyze_scalar_evolution_for_address_of (struct loop *loop, tree var) | |
2125 | { | |
2126 | return analyze_scalar_evolution (loop, build_fold_addr_expr (var)); | |
2127 | } | |
2128 | ||
9baba81b | 2129 | /* Analyze scalar evolution of use of VERSION in USE_LOOP with respect to |
f017bf5e | 2130 | WRTO_LOOP (which should be a superloop of USE_LOOP) |
a6f778b2 ZD |
2131 | |
2132 | FOLDED_CASTS is set to true if resolve_mixers used | |
2133 | chrec_convert_aggressive (TODO -- not really, we are way too conservative | |
b8698a0f L |
2134 | at the moment in order to keep things simple). |
2135 | ||
f017bf5e ZD |
2136 | To illustrate the meaning of USE_LOOP and WRTO_LOOP, consider the following |
2137 | example: | |
2138 | ||
2139 | for (i = 0; i < 100; i++) -- loop 1 | |
2140 | { | |
2141 | for (j = 0; j < 100; j++) -- loop 2 | |
2142 | { | |
2143 | k1 = i; | |
2144 | k2 = j; | |
2145 | ||
2146 | use2 (k1, k2); | |
2147 | ||
2148 | for (t = 0; t < 100; t++) -- loop 3 | |
2149 | use3 (k1, k2); | |
2150 | ||
2151 | } | |
2152 | use1 (k1, k2); | |
2153 | } | |
2154 | ||
2155 | Both k1 and k2 are invariants in loop3, thus | |
2156 | analyze_scalar_evolution_in_loop (loop3, loop3, k1) = k1 | |
2157 | analyze_scalar_evolution_in_loop (loop3, loop3, k2) = k2 | |
2158 | ||
2159 | As they are invariant, it does not matter whether we consider their | |
2160 | usage in loop 3 or loop 2, hence | |
2161 | analyze_scalar_evolution_in_loop (loop2, loop3, k1) = | |
2162 | analyze_scalar_evolution_in_loop (loop2, loop2, k1) = i | |
2163 | analyze_scalar_evolution_in_loop (loop2, loop3, k2) = | |
2164 | analyze_scalar_evolution_in_loop (loop2, loop2, k2) = [0,+,1]_2 | |
2165 | ||
2166 | Similarly for their evolutions with respect to loop 1. The values of K2 | |
2167 | in the use in loop 2 vary independently on loop 1, thus we cannot express | |
2168 | the evolution with respect to loop 1: | |
2169 | analyze_scalar_evolution_in_loop (loop1, loop3, k1) = | |
2170 | analyze_scalar_evolution_in_loop (loop1, loop2, k1) = [0,+,1]_1 | |
2171 | analyze_scalar_evolution_in_loop (loop1, loop3, k2) = | |
2172 | analyze_scalar_evolution_in_loop (loop1, loop2, k2) = dont_know | |
2173 | ||
2174 | The value of k2 in the use in loop 1 is known, though: | |
2175 | analyze_scalar_evolution_in_loop (loop1, loop1, k1) = [0,+,1]_1 | |
2176 | analyze_scalar_evolution_in_loop (loop1, loop1, k2) = 100 | |
2177 | */ | |
9baba81b SP |
2178 | |
2179 | static tree | |
2180 | analyze_scalar_evolution_in_loop (struct loop *wrto_loop, struct loop *use_loop, | |
a6f778b2 | 2181 | tree version, bool *folded_casts) |
9baba81b SP |
2182 | { |
2183 | bool val = false; | |
a6f778b2 | 2184 | tree ev = version, tmp; |
9baba81b | 2185 | |
b8698a0f | 2186 | /* We cannot just do |
f017bf5e ZD |
2187 | |
2188 | tmp = analyze_scalar_evolution (use_loop, version); | |
c70ed622 | 2189 | ev = resolve_mixers (wrto_loop, tmp, folded_casts); |
f017bf5e ZD |
2190 | |
2191 | as resolve_mixers would query the scalar evolution with respect to | |
2192 | wrto_loop. For example, in the situation described in the function | |
2193 | comment, suppose that wrto_loop = loop1, use_loop = loop3 and | |
2194 | version = k2. Then | |
2195 | ||
2196 | analyze_scalar_evolution (use_loop, version) = k2 | |
2197 | ||
c70ed622 BC |
2198 | and resolve_mixers (loop1, k2, folded_casts) finds that the value of |
2199 | k2 in loop 1 is 100, which is a wrong result, since we are interested | |
2200 | in the value in loop 3. | |
f017bf5e ZD |
2201 | |
2202 | Instead, we need to proceed from use_loop to wrto_loop loop by loop, | |
2203 | each time checking that there is no evolution in the inner loop. */ | |
2204 | ||
a6f778b2 ZD |
2205 | if (folded_casts) |
2206 | *folded_casts = false; | |
9baba81b SP |
2207 | while (1) |
2208 | { | |
a6f778b2 | 2209 | tmp = analyze_scalar_evolution (use_loop, ev); |
c70ed622 | 2210 | ev = resolve_mixers (use_loop, tmp, folded_casts); |
9baba81b SP |
2211 | |
2212 | if (use_loop == wrto_loop) | |
2213 | return ev; | |
2214 | ||
2215 | /* If the value of the use changes in the inner loop, we cannot express | |
2216 | its value in the outer loop (we might try to return interval chrec, | |
2217 | but we do not have a user for it anyway) */ | |
2218 | if (!no_evolution_in_loop_p (ev, use_loop->num, &val) | |
2219 | || !val) | |
2220 | return chrec_dont_know; | |
2221 | ||
9ba025a2 | 2222 | use_loop = loop_outer (use_loop); |
9baba81b SP |
2223 | } |
2224 | } | |
2225 | ||
eb0bc7af | 2226 | |
a3cc13cc RB |
2227 | /* Computes a hash function for database element ELT. */ |
2228 | ||
2229 | static inline hashval_t | |
2230 | hash_idx_scev_info (const void *elt_) | |
2231 | { | |
2232 | unsigned idx = ((size_t) elt_) - 2; | |
907dadbd | 2233 | return scev_info_hasher::hash (&global_cache->entries[idx]); |
a3cc13cc RB |
2234 | } |
2235 | ||
2236 | /* Compares database elements E1 and E2. */ | |
2237 | ||
2238 | static inline int | |
2239 | eq_idx_scev_info (const void *e1, const void *e2) | |
2240 | { | |
2241 | unsigned idx1 = ((size_t) e1) - 2; | |
907dadbd TS |
2242 | return scev_info_hasher::equal (&global_cache->entries[idx1], |
2243 | (const scev_info_str *) e2); | |
a3cc13cc RB |
2244 | } |
2245 | ||
0547c9b6 | 2246 | /* Returns from CACHE the slot number of the cached chrec for NAME. */ |
fdd43ac4 | 2247 | |
0547c9b6 | 2248 | static unsigned |
a3cc13cc | 2249 | get_instantiated_value_entry (instantiate_cache_type &cache, |
a68f286c | 2250 | tree name, edge instantiate_below) |
fdd43ac4 | 2251 | { |
0547c9b6 | 2252 | if (!cache.map) |
fdd43ac4 | 2253 | { |
a3cc13cc | 2254 | cache.map = htab_create (10, hash_idx_scev_info, eq_idx_scev_info, NULL); |
fdd43ac4 RB |
2255 | cache.entries.create (10); |
2256 | } | |
b8698a0f | 2257 | |
a3cc13cc RB |
2258 | scev_info_str e; |
2259 | e.name_version = SSA_NAME_VERSION (name); | |
a68f286c | 2260 | e.instantiated_below = instantiate_below->dest->index; |
a3cc13cc | 2261 | void **slot = htab_find_slot_with_hash (cache.map, &e, |
907dadbd | 2262 | scev_info_hasher::hash (&e), INSERT); |
a3cc13cc | 2263 | if (!*slot) |
fdd43ac4 RB |
2264 | { |
2265 | e.chrec = chrec_not_analyzed_yet; | |
a3cc13cc | 2266 | *slot = (void *)(size_t)(cache.entries.length () + 2); |
fdd43ac4 | 2267 | cache.entries.safe_push (e); |
fdd43ac4 RB |
2268 | } |
2269 | ||
a3cc13cc | 2270 | return ((size_t)*slot) - 2; |
eb0bc7af ZD |
2271 | } |
2272 | ||
0547c9b6 | 2273 | |
18aed06a SP |
2274 | /* Return the closed_loop_phi node for VAR. If there is none, return |
2275 | NULL_TREE. */ | |
2276 | ||
2277 | static tree | |
2278 | loop_closed_phi_def (tree var) | |
2279 | { | |
2280 | struct loop *loop; | |
2281 | edge exit; | |
538dd0b7 DM |
2282 | gphi *phi; |
2283 | gphi_iterator psi; | |
18aed06a SP |
2284 | |
2285 | if (var == NULL_TREE | |
2286 | || TREE_CODE (var) != SSA_NAME) | |
2287 | return NULL_TREE; | |
2288 | ||
2289 | loop = loop_containing_stmt (SSA_NAME_DEF_STMT (var)); | |
ac8f6c69 | 2290 | exit = single_exit (loop); |
18aed06a SP |
2291 | if (!exit) |
2292 | return NULL_TREE; | |
2293 | ||
726a989a RB |
2294 | for (psi = gsi_start_phis (exit->dest); !gsi_end_p (psi); gsi_next (&psi)) |
2295 | { | |
538dd0b7 | 2296 | phi = psi.phi (); |
726a989a RB |
2297 | if (PHI_ARG_DEF_FROM_EDGE (phi, exit) == var) |
2298 | return PHI_RESULT (phi); | |
2299 | } | |
18aed06a SP |
2300 | |
2301 | return NULL_TREE; | |
2302 | } | |
2303 | ||
a68f286c | 2304 | static tree instantiate_scev_r (edge, struct loop *, struct loop *, |
c70ed622 | 2305 | tree, bool *, int); |
320f5a78 SP |
2306 | |
2307 | /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW | |
2308 | and EVOLUTION_LOOP, that were left under a symbolic form. | |
2309 | ||
2495a183 | 2310 | CHREC is an SSA_NAME to be instantiated. |
320f5a78 SP |
2311 | |
2312 | CACHE is the cache of already instantiated values. | |
2313 | ||
c70ed622 BC |
2314 | Variable pointed by FOLD_CONVERSIONS is set to TRUE when the |
2315 | conversions that may wrap in signed/pointer type are folded, as long | |
2316 | as the value of the chrec is preserved. If FOLD_CONVERSIONS is NULL | |
2317 | then we don't do such fold. | |
320f5a78 SP |
2318 | |
2319 | SIZE_EXPR is used for computing the size of the expression to be | |
2320 | instantiated, and to stop if it exceeds some limit. */ | |
2321 | ||
2322 | static tree | |
a68f286c | 2323 | instantiate_scev_name (edge instantiate_below, |
8b679c9b RB |
2324 | struct loop *evolution_loop, struct loop *inner_loop, |
2325 | tree chrec, | |
c70ed622 | 2326 | bool *fold_conversions, |
4a8fb1a1 | 2327 | int size_expr) |
320f5a78 | 2328 | { |
2495a183 SP |
2329 | tree res; |
2330 | struct loop *def_loop; | |
2331 | basic_block def_bb = gimple_bb (SSA_NAME_DEF_STMT (chrec)); | |
20179b0d | 2332 | |
92900aec | 2333 | /* A parameter, nothing to do. */ |
2495a183 | 2334 | if (!def_bb |
92900aec | 2335 | || !dominated_by_p (CDI_DOMINATORS, def_bb, instantiate_below->dest)) |
2495a183 | 2336 | return chrec; |
20179b0d | 2337 | |
2495a183 SP |
2338 | /* We cache the value of instantiated variable to avoid exponential |
2339 | time complexity due to reevaluations. We also store the convenient | |
2340 | value in the cache in order to prevent infinite recursion -- we do | |
2341 | not want to instantiate the SSA_NAME if it is in a mixer | |
2342 | structure. This is used for avoiding the instantiation of | |
2343 | recursively defined functions, such as: | |
320f5a78 | 2344 | |
2495a183 | 2345 | | a_2 -> {0, +, 1, +, a_2}_1 */ |
20179b0d | 2346 | |
a3cc13cc RB |
2347 | unsigned si = get_instantiated_value_entry (*global_cache, |
2348 | chrec, instantiate_below); | |
0547c9b6 RB |
2349 | if (global_cache->get (si) != chrec_not_analyzed_yet) |
2350 | return global_cache->get (si); | |
20179b0d | 2351 | |
fdd43ac4 | 2352 | /* On recursion return chrec_dont_know. */ |
0547c9b6 | 2353 | global_cache->set (si, chrec_dont_know); |
320f5a78 | 2354 | |
2495a183 SP |
2355 | def_loop = find_common_loop (evolution_loop, def_bb->loop_father); |
2356 | ||
a68f286c RB |
2357 | if (! dominated_by_p (CDI_DOMINATORS, |
2358 | def_loop->header, instantiate_below->dest)) | |
2359 | { | |
2360 | gimple *def = SSA_NAME_DEF_STMT (chrec); | |
2361 | if (gassign *ass = dyn_cast <gassign *> (def)) | |
2362 | { | |
2363 | switch (gimple_assign_rhs_class (ass)) | |
2364 | { | |
2365 | case GIMPLE_UNARY_RHS: | |
2366 | { | |
2367 | tree op0 = instantiate_scev_r (instantiate_below, evolution_loop, | |
2368 | inner_loop, gimple_assign_rhs1 (ass), | |
2369 | fold_conversions, size_expr); | |
2370 | if (op0 == chrec_dont_know) | |
2371 | return chrec_dont_know; | |
2372 | res = fold_build1 (gimple_assign_rhs_code (ass), | |
2373 | TREE_TYPE (chrec), op0); | |
2374 | break; | |
2375 | } | |
2376 | case GIMPLE_BINARY_RHS: | |
2377 | { | |
2378 | tree op0 = instantiate_scev_r (instantiate_below, evolution_loop, | |
2379 | inner_loop, gimple_assign_rhs1 (ass), | |
2380 | fold_conversions, size_expr); | |
2381 | if (op0 == chrec_dont_know) | |
2382 | return chrec_dont_know; | |
2383 | tree op1 = instantiate_scev_r (instantiate_below, evolution_loop, | |
2384 | inner_loop, gimple_assign_rhs2 (ass), | |
2385 | fold_conversions, size_expr); | |
2386 | if (op1 == chrec_dont_know) | |
2387 | return chrec_dont_know; | |
2388 | res = fold_build2 (gimple_assign_rhs_code (ass), | |
2389 | TREE_TYPE (chrec), op0, op1); | |
2390 | break; | |
2391 | } | |
2392 | default: | |
2393 | res = chrec_dont_know; | |
2394 | } | |
2395 | } | |
2396 | else | |
2397 | res = chrec_dont_know; | |
2398 | global_cache->set (si, res); | |
2399 | return res; | |
2400 | } | |
2401 | ||
320f5a78 SP |
2402 | /* If the analysis yields a parametric chrec, instantiate the |
2403 | result again. */ | |
2404 | res = analyze_scalar_evolution (def_loop, chrec); | |
2405 | ||
2847388e | 2406 | /* Don't instantiate default definitions. */ |
320f5a78 | 2407 | if (TREE_CODE (res) == SSA_NAME |
2847388e SP |
2408 | && SSA_NAME_IS_DEFAULT_DEF (res)) |
2409 | ; | |
2410 | ||
2411 | /* Don't instantiate loop-closed-ssa phi nodes. */ | |
2412 | else if (TREE_CODE (res) == SSA_NAME | |
2413 | && loop_depth (loop_containing_stmt (SSA_NAME_DEF_STMT (res))) | |
2414 | > loop_depth (def_loop)) | |
320f5a78 SP |
2415 | { |
2416 | if (res == chrec) | |
2417 | res = loop_closed_phi_def (chrec); | |
2418 | else | |
2419 | res = chrec; | |
2420 | ||
7472eb13 SP |
2421 | /* When there is no loop_closed_phi_def, it means that the |
2422 | variable is not used after the loop: try to still compute the | |
2423 | value of the variable when exiting the loop. */ | |
2424 | if (res == NULL_TREE) | |
2425 | { | |
2426 | loop_p loop = loop_containing_stmt (SSA_NAME_DEF_STMT (chrec)); | |
2427 | res = analyze_scalar_evolution (loop, chrec); | |
2428 | res = compute_overall_effect_of_inner_loop (loop, res); | |
8b679c9b RB |
2429 | res = instantiate_scev_r (instantiate_below, evolution_loop, |
2430 | inner_loop, res, | |
0547c9b6 | 2431 | fold_conversions, size_expr); |
7472eb13 | 2432 | } |
a68f286c RB |
2433 | else if (dominated_by_p (CDI_DOMINATORS, |
2434 | gimple_bb (SSA_NAME_DEF_STMT (res)), | |
2435 | instantiate_below->dest)) | |
320f5a78 SP |
2436 | res = chrec_dont_know; |
2437 | } | |
2438 | ||
2439 | else if (res != chrec_dont_know) | |
8b679c9b RB |
2440 | { |
2441 | if (inner_loop | |
63fdb7be | 2442 | && def_bb->loop_father != inner_loop |
8b679c9b RB |
2443 | && !flow_loop_nested_p (def_bb->loop_father, inner_loop)) |
2444 | /* ??? We could try to compute the overall effect of the loop here. */ | |
2445 | res = chrec_dont_know; | |
2446 | else | |
2447 | res = instantiate_scev_r (instantiate_below, evolution_loop, | |
2448 | inner_loop, res, | |
0547c9b6 | 2449 | fold_conversions, size_expr); |
8b679c9b | 2450 | } |
320f5a78 SP |
2451 | |
2452 | /* Store the correct value to the cache. */ | |
0547c9b6 | 2453 | global_cache->set (si, res); |
320f5a78 | 2454 | return res; |
320f5a78 SP |
2455 | } |
2456 | ||
ec6636eb SP |
2457 | /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW |
2458 | and EVOLUTION_LOOP, that were left under a symbolic form. | |
2459 | ||
2460 | CHREC is a polynomial chain of recurrence to be instantiated. | |
2461 | ||
2462 | CACHE is the cache of already instantiated values. | |
2463 | ||
c70ed622 BC |
2464 | Variable pointed by FOLD_CONVERSIONS is set to TRUE when the |
2465 | conversions that may wrap in signed/pointer type are folded, as long | |
2466 | as the value of the chrec is preserved. If FOLD_CONVERSIONS is NULL | |
2467 | then we don't do such fold. | |
ec6636eb SP |
2468 | |
2469 | SIZE_EXPR is used for computing the size of the expression to be | |
2470 | instantiated, and to stop if it exceeds some limit. */ | |
2471 | ||
2472 | static tree | |
a68f286c | 2473 | instantiate_scev_poly (edge instantiate_below, |
8b679c9b | 2474 | struct loop *evolution_loop, struct loop *, |
c70ed622 | 2475 | tree chrec, bool *fold_conversions, int size_expr) |
ec6636eb SP |
2476 | { |
2477 | tree op1; | |
9e5dc77f | 2478 | tree op0 = instantiate_scev_r (instantiate_below, evolution_loop, |
8b679c9b | 2479 | get_chrec_loop (chrec), |
0547c9b6 | 2480 | CHREC_LEFT (chrec), fold_conversions, |
ec6636eb SP |
2481 | size_expr); |
2482 | if (op0 == chrec_dont_know) | |
2483 | return chrec_dont_know; | |
2484 | ||
9e5dc77f | 2485 | op1 = instantiate_scev_r (instantiate_below, evolution_loop, |
8b679c9b | 2486 | get_chrec_loop (chrec), |
0547c9b6 | 2487 | CHREC_RIGHT (chrec), fold_conversions, |
ec6636eb SP |
2488 | size_expr); |
2489 | if (op1 == chrec_dont_know) | |
2490 | return chrec_dont_know; | |
2491 | ||
2492 | if (CHREC_LEFT (chrec) != op0 | |
2493 | || CHREC_RIGHT (chrec) != op1) | |
2494 | { | |
2495 | op1 = chrec_convert_rhs (chrec_type (op0), op1, NULL); | |
8b679c9b | 2496 | chrec = build_polynomial_chrec (CHREC_VARIABLE (chrec), op0, op1); |
ec6636eb | 2497 | } |
4bf4e169 | 2498 | |
ec6636eb SP |
2499 | return chrec; |
2500 | } | |
2501 | ||
15fda317 SP |
2502 | /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW |
2503 | and EVOLUTION_LOOP, that were left under a symbolic form. | |
2504 | ||
ffa34f4b | 2505 | "C0 CODE C1" is a binary expression of type TYPE to be instantiated. |
15fda317 SP |
2506 | |
2507 | CACHE is the cache of already instantiated values. | |
2508 | ||
c70ed622 BC |
2509 | Variable pointed by FOLD_CONVERSIONS is set to TRUE when the |
2510 | conversions that may wrap in signed/pointer type are folded, as long | |
2511 | as the value of the chrec is preserved. If FOLD_CONVERSIONS is NULL | |
2512 | then we don't do such fold. | |
15fda317 SP |
2513 | |
2514 | SIZE_EXPR is used for computing the size of the expression to be | |
2515 | instantiated, and to stop if it exceeds some limit. */ | |
2516 | ||
2517 | static tree | |
a68f286c | 2518 | instantiate_scev_binary (edge instantiate_below, |
8b679c9b RB |
2519 | struct loop *evolution_loop, struct loop *inner_loop, |
2520 | tree chrec, enum tree_code code, | |
ffa34f4b | 2521 | tree type, tree c0, tree c1, |
c70ed622 | 2522 | bool *fold_conversions, int size_expr) |
15fda317 SP |
2523 | { |
2524 | tree op1; | |
8b679c9b | 2525 | tree op0 = instantiate_scev_r (instantiate_below, evolution_loop, inner_loop, |
0547c9b6 | 2526 | c0, fold_conversions, size_expr); |
15fda317 SP |
2527 | if (op0 == chrec_dont_know) |
2528 | return chrec_dont_know; | |
2529 | ||
577d6588 RB |
2530 | /* While we eventually compute the same op1 if c0 == c1 the process |
2531 | of doing this is expensive so the following short-cut prevents | |
2532 | exponential compile-time behavior. */ | |
2533 | if (c0 != c1) | |
2534 | { | |
2535 | op1 = instantiate_scev_r (instantiate_below, evolution_loop, inner_loop, | |
2536 | c1, fold_conversions, size_expr); | |
2537 | if (op1 == chrec_dont_know) | |
2538 | return chrec_dont_know; | |
2539 | } | |
2540 | else | |
2541 | op1 = op0; | |
15fda317 | 2542 | |
ffa34f4b SP |
2543 | if (c0 != op0 |
2544 | || c1 != op1) | |
15fda317 | 2545 | { |
15fda317 SP |
2546 | op0 = chrec_convert (type, op0, NULL); |
2547 | op1 = chrec_convert_rhs (type, op1, NULL); | |
2548 | ||
ffa34f4b | 2549 | switch (code) |
15fda317 SP |
2550 | { |
2551 | case POINTER_PLUS_EXPR: | |
2552 | case PLUS_EXPR: | |
2553 | return chrec_fold_plus (type, op0, op1); | |
2554 | ||
2555 | case MINUS_EXPR: | |
2556 | return chrec_fold_minus (type, op0, op1); | |
2557 | ||
2558 | case MULT_EXPR: | |
2559 | return chrec_fold_multiply (type, op0, op1); | |
2560 | ||
2561 | default: | |
2562 | gcc_unreachable (); | |
2563 | } | |
2564 | } | |
2565 | ||
ffa34f4b | 2566 | return chrec ? chrec : fold_build2 (code, type, c0, c1); |
15fda317 SP |
2567 | } |
2568 | ||
a213b219 | 2569 | /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW |
9c382ce9 SP |
2570 | and EVOLUTION_LOOP, that were left under a symbolic form. |
2571 | ||
2572 | "CHREC" that stands for a convert expression "(TYPE) OP" is to be | |
2573 | instantiated. | |
2574 | ||
2575 | CACHE is the cache of already instantiated values. | |
2576 | ||
c70ed622 BC |
2577 | Variable pointed by FOLD_CONVERSIONS is set to TRUE when the |
2578 | conversions that may wrap in signed/pointer type are folded, as long | |
2579 | as the value of the chrec is preserved. If FOLD_CONVERSIONS is NULL | |
2580 | then we don't do such fold. | |
9c382ce9 SP |
2581 | |
2582 | SIZE_EXPR is used for computing the size of the expression to be | |
2583 | instantiated, and to stop if it exceeds some limit. */ | |
2584 | ||
2585 | static tree | |
a68f286c | 2586 | instantiate_scev_convert (edge instantiate_below, |
8b679c9b | 2587 | struct loop *evolution_loop, struct loop *inner_loop, |
0547c9b6 | 2588 | tree chrec, tree type, tree op, |
c70ed622 | 2589 | bool *fold_conversions, int size_expr) |
9c382ce9 | 2590 | { |
8b679c9b RB |
2591 | tree op0 = instantiate_scev_r (instantiate_below, evolution_loop, |
2592 | inner_loop, op, | |
0547c9b6 | 2593 | fold_conversions, size_expr); |
9c382ce9 SP |
2594 | |
2595 | if (op0 == chrec_dont_know) | |
2596 | return chrec_dont_know; | |
2597 | ||
2598 | if (fold_conversions) | |
2599 | { | |
c70ed622 | 2600 | tree tmp = chrec_convert_aggressive (type, op0, fold_conversions); |
9c382ce9 SP |
2601 | if (tmp) |
2602 | return tmp; | |
9c382ce9 | 2603 | |
c70ed622 BC |
2604 | /* If we used chrec_convert_aggressive, we can no longer assume that |
2605 | signed chrecs do not overflow, as chrec_convert does, so avoid | |
2606 | calling it in that case. */ | |
2607 | if (*fold_conversions) | |
2608 | { | |
2609 | if (chrec && op0 == op) | |
2610 | return chrec; | |
9c382ce9 | 2611 | |
c70ed622 BC |
2612 | return fold_convert (type, op0); |
2613 | } | |
2614 | } | |
9c382ce9 SP |
2615 | |
2616 | return chrec_convert (type, op0, NULL); | |
2617 | } | |
2618 | ||
7ec0665d SP |
2619 | /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW |
2620 | and EVOLUTION_LOOP, that were left under a symbolic form. | |
2621 | ||
4b9d48a1 | 2622 | CHREC is a BIT_NOT_EXPR or a NEGATE_EXPR expression to be instantiated. |
7ec0665d | 2623 | Handle ~X as -1 - X. |
4b9d48a1 | 2624 | Handle -X as -1 * X. |
7ec0665d SP |
2625 | |
2626 | CACHE is the cache of already instantiated values. | |
2627 | ||
c70ed622 BC |
2628 | Variable pointed by FOLD_CONVERSIONS is set to TRUE when the |
2629 | conversions that may wrap in signed/pointer type are folded, as long | |
2630 | as the value of the chrec is preserved. If FOLD_CONVERSIONS is NULL | |
2631 | then we don't do such fold. | |
7ec0665d SP |
2632 | |
2633 | SIZE_EXPR is used for computing the size of the expression to be | |
2634 | instantiated, and to stop if it exceeds some limit. */ | |
2635 | ||
2636 | static tree | |
a68f286c | 2637 | instantiate_scev_not (edge instantiate_below, |
8b679c9b RB |
2638 | struct loop *evolution_loop, struct loop *inner_loop, |
2639 | tree chrec, | |
20179b0d | 2640 | enum tree_code code, tree type, tree op, |
c70ed622 | 2641 | bool *fold_conversions, int size_expr) |
7ec0665d | 2642 | { |
8b679c9b RB |
2643 | tree op0 = instantiate_scev_r (instantiate_below, evolution_loop, |
2644 | inner_loop, op, | |
0547c9b6 | 2645 | fold_conversions, size_expr); |
20179b0d | 2646 | |
7ec0665d SP |
2647 | if (op0 == chrec_dont_know) |
2648 | return chrec_dont_know; | |
2649 | ||
20179b0d | 2650 | if (op != op0) |
7ec0665d SP |
2651 | { |
2652 | op0 = chrec_convert (type, op0, NULL); | |
4b9d48a1 | 2653 | |
20179b0d | 2654 | switch (code) |
4b9d48a1 SP |
2655 | { |
2656 | case BIT_NOT_EXPR: | |
2657 | return chrec_fold_minus | |
2658 | (type, fold_convert (type, integer_minus_one_node), op0); | |
2659 | ||
2660 | case NEGATE_EXPR: | |
2661 | return chrec_fold_multiply | |
2662 | (type, fold_convert (type, integer_minus_one_node), op0); | |
2663 | ||
2664 | default: | |
2665 | gcc_unreachable (); | |
2666 | } | |
7ec0665d | 2667 | } |
4b9d48a1 | 2668 | |
20179b0d | 2669 | return chrec ? chrec : fold_build1 (code, type, op0); |
7ec0665d SP |
2670 | } |
2671 | ||
9e5dc77f SP |
2672 | /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW |
2673 | and EVOLUTION_LOOP, that were left under a symbolic form. | |
2674 | ||
2675 | CHREC is the scalar evolution to instantiate. | |
2676 | ||
2677 | CACHE is the cache of already instantiated values. | |
2282a0e6 | 2678 | |
c70ed622 BC |
2679 | Variable pointed by FOLD_CONVERSIONS is set to TRUE when the |
2680 | conversions that may wrap in signed/pointer type are folded, as long | |
2681 | as the value of the chrec is preserved. If FOLD_CONVERSIONS is NULL | |
2682 | then we don't do such fold. | |
9e5dc77f SP |
2683 | |
2684 | SIZE_EXPR is used for computing the size of the expression to be | |
2685 | instantiated, and to stop if it exceeds some limit. */ | |
2686 | ||
2687 | static tree | |
a68f286c | 2688 | instantiate_scev_r (edge instantiate_below, |
8b679c9b RB |
2689 | struct loop *evolution_loop, struct loop *inner_loop, |
2690 | tree chrec, | |
c70ed622 | 2691 | bool *fold_conversions, int size_expr) |
9e5dc77f | 2692 | { |
47ae9e4c SP |
2693 | /* Give up if the expression is larger than the MAX that we allow. */ |
2694 | if (size_expr++ > PARAM_VALUE (PARAM_SCEV_MAX_EXPR_SIZE)) | |
2695 | return chrec_dont_know; | |
2696 | ||
81fada9a JJ |
2697 | if (chrec == NULL_TREE |
2698 | || automatically_generated_chrec_p (chrec) | |
d7770457 | 2699 | || is_gimple_min_invariant (chrec)) |
9baba81b SP |
2700 | return chrec; |
2701 | ||
2702 | switch (TREE_CODE (chrec)) | |
2703 | { | |
2704 | case SSA_NAME: | |
8b679c9b RB |
2705 | return instantiate_scev_name (instantiate_below, evolution_loop, |
2706 | inner_loop, chrec, | |
0547c9b6 | 2707 | fold_conversions, size_expr); |
9baba81b SP |
2708 | |
2709 | case POLYNOMIAL_CHREC: | |
8b679c9b RB |
2710 | return instantiate_scev_poly (instantiate_below, evolution_loop, |
2711 | inner_loop, chrec, | |
0547c9b6 | 2712 | fold_conversions, size_expr); |
9baba81b | 2713 | |
5be014d5 | 2714 | case POINTER_PLUS_EXPR: |
9baba81b | 2715 | case PLUS_EXPR: |
9baba81b | 2716 | case MINUS_EXPR: |
9baba81b | 2717 | case MULT_EXPR: |
8b679c9b RB |
2718 | return instantiate_scev_binary (instantiate_below, evolution_loop, |
2719 | inner_loop, chrec, | |
ffa34f4b SP |
2720 | TREE_CODE (chrec), chrec_type (chrec), |
2721 | TREE_OPERAND (chrec, 0), | |
2722 | TREE_OPERAND (chrec, 1), | |
0547c9b6 | 2723 | fold_conversions, size_expr); |
9baba81b | 2724 | |
1043771b | 2725 | CASE_CONVERT: |
8b679c9b RB |
2726 | return instantiate_scev_convert (instantiate_below, evolution_loop, |
2727 | inner_loop, chrec, | |
9c382ce9 | 2728 | TREE_TYPE (chrec), TREE_OPERAND (chrec, 0), |
0547c9b6 | 2729 | fold_conversions, size_expr); |
9baba81b | 2730 | |
4b9d48a1 | 2731 | case NEGATE_EXPR: |
418df9d7 | 2732 | case BIT_NOT_EXPR: |
8b679c9b RB |
2733 | return instantiate_scev_not (instantiate_below, evolution_loop, |
2734 | inner_loop, chrec, | |
20179b0d SP |
2735 | TREE_CODE (chrec), TREE_TYPE (chrec), |
2736 | TREE_OPERAND (chrec, 0), | |
0547c9b6 | 2737 | fold_conversions, size_expr); |
418df9d7 | 2738 | |
4c7d6755 | 2739 | case ADDR_EXPR: |
a68f286c RB |
2740 | if (is_gimple_min_invariant (chrec)) |
2741 | return chrec; | |
2742 | /* Fallthru. */ | |
9baba81b SP |
2743 | case SCEV_NOT_KNOWN: |
2744 | return chrec_dont_know; | |
2745 | ||
2746 | case SCEV_KNOWN: | |
2747 | return chrec_known; | |
15fda317 | 2748 | |
9baba81b | 2749 | default: |
a68f286c RB |
2750 | if (CONSTANT_CLASS_P (chrec)) |
2751 | return chrec; | |
2752 | return chrec_dont_know; | |
9baba81b | 2753 | } |
9baba81b | 2754 | } |
e9eb809d ZD |
2755 | |
2756 | /* Analyze all the parameters of the chrec that were left under a | |
a213b219 SP |
2757 | symbolic form. INSTANTIATE_BELOW is the basic block that stops the |
2758 | recursive instantiation of parameters: a parameter is a variable | |
2759 | that is defined in a basic block that dominates INSTANTIATE_BELOW or | |
2760 | a function parameter. */ | |
e9eb809d ZD |
2761 | |
2762 | tree | |
a68f286c | 2763 | instantiate_scev (edge instantiate_below, struct loop *evolution_loop, |
3f227a8c | 2764 | tree chrec) |
e9eb809d | 2765 | { |
9baba81b SP |
2766 | tree res; |
2767 | ||
dfedbe40 | 2768 | if (dump_file && (dump_flags & TDF_SCEV)) |
9baba81b | 2769 | { |
3f227a8c | 2770 | fprintf (dump_file, "(instantiate_scev \n"); |
a68f286c RB |
2771 | fprintf (dump_file, " (instantiate_below = %d -> %d)\n", |
2772 | instantiate_below->src->index, instantiate_below->dest->index); | |
2773 | if (evolution_loop) | |
2774 | fprintf (dump_file, " (evolution_loop = %d)\n", evolution_loop->num); | |
9baba81b | 2775 | fprintf (dump_file, " (chrec = "); |
ef6cb4c7 | 2776 | print_generic_expr (dump_file, chrec); |
9baba81b SP |
2777 | fprintf (dump_file, ")\n"); |
2778 | } | |
b8698a0f | 2779 | |
0547c9b6 RB |
2780 | bool destr = false; |
2781 | if (!global_cache) | |
2782 | { | |
2783 | global_cache = new instantiate_cache_type; | |
2784 | destr = true; | |
2785 | } | |
2786 | ||
8b679c9b | 2787 | res = instantiate_scev_r (instantiate_below, evolution_loop, |
c70ed622 | 2788 | NULL, chrec, NULL, 0); |
0547c9b6 RB |
2789 | |
2790 | if (destr) | |
2791 | { | |
2792 | delete global_cache; | |
2793 | global_cache = NULL; | |
2794 | } | |
9baba81b | 2795 | |
dfedbe40 | 2796 | if (dump_file && (dump_flags & TDF_SCEV)) |
9baba81b SP |
2797 | { |
2798 | fprintf (dump_file, " (res = "); | |
ef6cb4c7 | 2799 | print_generic_expr (dump_file, res); |
9baba81b SP |
2800 | fprintf (dump_file, "))\n"); |
2801 | } | |
eb0bc7af | 2802 | |
9baba81b SP |
2803 | return res; |
2804 | } | |
2805 | ||
2806 | /* Similar to instantiate_parameters, but does not introduce the | |
2282a0e6 ZD |
2807 | evolutions in outer loops for LOOP invariants in CHREC, and does not |
2808 | care about causing overflows, as long as they do not affect value | |
2809 | of an expression. */ | |
9baba81b | 2810 | |
3cb960c7 | 2811 | tree |
c70ed622 | 2812 | resolve_mixers (struct loop *loop, tree chrec, bool *folded_casts) |
9baba81b | 2813 | { |
0547c9b6 | 2814 | bool destr = false; |
c70ed622 | 2815 | bool fold_conversions = false; |
0547c9b6 RB |
2816 | if (!global_cache) |
2817 | { | |
2818 | global_cache = new instantiate_cache_type; | |
2819 | destr = true; | |
2820 | } | |
2821 | ||
a68f286c | 2822 | tree ret = instantiate_scev_r (loop_preheader_edge (loop), loop, NULL, |
c70ed622 BC |
2823 | chrec, &fold_conversions, 0); |
2824 | ||
2825 | if (folded_casts && !*folded_casts) | |
2826 | *folded_casts = fold_conversions; | |
0547c9b6 RB |
2827 | |
2828 | if (destr) | |
2829 | { | |
2830 | delete global_cache; | |
2831 | global_cache = NULL; | |
2832 | } | |
2833 | ||
eb0bc7af | 2834 | return ret; |
9baba81b SP |
2835 | } |
2836 | ||
b8698a0f | 2837 | /* Entry point for the analysis of the number of iterations pass. |
9baba81b SP |
2838 | This function tries to safely approximate the number of iterations |
2839 | the loop will run. When this property is not decidable at compile | |
0a74c758 SP |
2840 | time, the result is chrec_dont_know. Otherwise the result is a |
2841 | scalar or a symbolic parameter. When the number of iterations may | |
2842 | be equal to zero and the property cannot be determined at compile | |
2843 | time, the result is a COND_EXPR that represents in a symbolic form | |
2844 | the conditions under which the number of iterations is not zero. | |
b8698a0f | 2845 | |
9baba81b | 2846 | Example of analysis: suppose that the loop has an exit condition: |
b8698a0f | 2847 | |
9baba81b | 2848 | "if (b > 49) goto end_loop;" |
b8698a0f | 2849 | |
9baba81b SP |
2850 | and that in a previous analysis we have determined that the |
2851 | variable 'b' has an evolution function: | |
b8698a0f L |
2852 | |
2853 | "EF = {23, +, 5}_2". | |
2854 | ||
9baba81b SP |
2855 | When we evaluate the function at the point 5, i.e. the value of the |
2856 | variable 'b' after 5 iterations in the loop, we have EF (5) = 48, | |
2857 | and EF (6) = 53. In this case the value of 'b' on exit is '53' and | |
2858 | the loop body has been executed 6 times. */ | |
2859 | ||
b8698a0f | 2860 | tree |
a14865db | 2861 | number_of_latch_executions (struct loop *loop) |
9baba81b | 2862 | { |
9baba81b SP |
2863 | edge exit; |
2864 | struct tree_niter_desc niter_desc; | |
0a74c758 SP |
2865 | tree may_be_zero; |
2866 | tree res; | |
9baba81b | 2867 | |
0a74c758 | 2868 | /* Determine whether the number of iterations in loop has already |
9baba81b SP |
2869 | been computed. */ |
2870 | res = loop->nb_iterations; | |
2871 | if (res) | |
2872 | return res; | |
0a74c758 SP |
2873 | |
2874 | may_be_zero = NULL_TREE; | |
9baba81b | 2875 | |
dfedbe40 | 2876 | if (dump_file && (dump_flags & TDF_SCEV)) |
0a74c758 | 2877 | fprintf (dump_file, "(number_of_iterations_in_loop = \n"); |
b8698a0f | 2878 | |
0a74c758 | 2879 | res = chrec_dont_know; |
ac8f6c69 | 2880 | exit = single_exit (loop); |
9baba81b | 2881 | |
0a74c758 SP |
2882 | if (exit && number_of_iterations_exit (loop, exit, &niter_desc, false)) |
2883 | { | |
2884 | may_be_zero = niter_desc.may_be_zero; | |
2885 | res = niter_desc.niter; | |
2886 | } | |
2887 | ||
2888 | if (res == chrec_dont_know | |
2889 | || !may_be_zero | |
2890 | || integer_zerop (may_be_zero)) | |
2891 | ; | |
2892 | else if (integer_nonzerop (may_be_zero)) | |
2893 | res = build_int_cst (TREE_TYPE (res), 0); | |
9baba81b | 2894 | |
0a74c758 SP |
2895 | else if (COMPARISON_CLASS_P (may_be_zero)) |
2896 | res = fold_build3 (COND_EXPR, TREE_TYPE (res), may_be_zero, | |
2897 | build_int_cst (TREE_TYPE (res), 0), res); | |
9baba81b SP |
2898 | else |
2899 | res = chrec_dont_know; | |
2900 | ||
dfedbe40 | 2901 | if (dump_file && (dump_flags & TDF_SCEV)) |
0a74c758 SP |
2902 | { |
2903 | fprintf (dump_file, " (set_nb_iterations_in_loop = "); | |
ef6cb4c7 | 2904 | print_generic_expr (dump_file, res); |
0a74c758 SP |
2905 | fprintf (dump_file, "))\n"); |
2906 | } | |
2907 | ||
2908 | loop->nb_iterations = res; | |
2909 | return res; | |
9baba81b | 2910 | } |
9baba81b SP |
2911 | \f |
2912 | ||
2913 | /* Counters for the stats. */ | |
2914 | ||
b8698a0f | 2915 | struct chrec_stats |
9baba81b SP |
2916 | { |
2917 | unsigned nb_chrecs; | |
2918 | unsigned nb_affine; | |
2919 | unsigned nb_affine_multivar; | |
2920 | unsigned nb_higher_poly; | |
2921 | unsigned nb_chrec_dont_know; | |
2922 | unsigned nb_undetermined; | |
2923 | }; | |
2924 | ||
2925 | /* Reset the counters. */ | |
2926 | ||
2927 | static inline void | |
2928 | reset_chrecs_counters (struct chrec_stats *stats) | |
2929 | { | |
2930 | stats->nb_chrecs = 0; | |
2931 | stats->nb_affine = 0; | |
2932 | stats->nb_affine_multivar = 0; | |
2933 | stats->nb_higher_poly = 0; | |
2934 | stats->nb_chrec_dont_know = 0; | |
2935 | stats->nb_undetermined = 0; | |
2936 | } | |
2937 | ||
2938 | /* Dump the contents of a CHREC_STATS structure. */ | |
2939 | ||
2940 | static void | |
2941 | dump_chrecs_stats (FILE *file, struct chrec_stats *stats) | |
2942 | { | |
2943 | fprintf (file, "\n(\n"); | |
2944 | fprintf (file, "-----------------------------------------\n"); | |
2945 | fprintf (file, "%d\taffine univariate chrecs\n", stats->nb_affine); | |
2946 | fprintf (file, "%d\taffine multivariate chrecs\n", stats->nb_affine_multivar); | |
b8698a0f | 2947 | fprintf (file, "%d\tdegree greater than 2 polynomials\n", |
9baba81b SP |
2948 | stats->nb_higher_poly); |
2949 | fprintf (file, "%d\tchrec_dont_know chrecs\n", stats->nb_chrec_dont_know); | |
2950 | fprintf (file, "-----------------------------------------\n"); | |
2951 | fprintf (file, "%d\ttotal chrecs\n", stats->nb_chrecs); | |
b8698a0f | 2952 | fprintf (file, "%d\twith undetermined coefficients\n", |
9baba81b SP |
2953 | stats->nb_undetermined); |
2954 | fprintf (file, "-----------------------------------------\n"); | |
b8698a0f | 2955 | fprintf (file, "%d\tchrecs in the scev database\n", |
907dadbd | 2956 | (int) scalar_evolution_info->elements ()); |
9baba81b SP |
2957 | fprintf (file, "%d\tsets in the scev database\n", nb_set_scev); |
2958 | fprintf (file, "%d\tgets in the scev database\n", nb_get_scev); | |
2959 | fprintf (file, "-----------------------------------------\n"); | |
2960 | fprintf (file, ")\n\n"); | |
2961 | } | |
2962 | ||
2963 | /* Gather statistics about CHREC. */ | |
2964 | ||
2965 | static void | |
2966 | gather_chrec_stats (tree chrec, struct chrec_stats *stats) | |
2967 | { | |
2968 | if (dump_file && (dump_flags & TDF_STATS)) | |
2969 | { | |
2970 | fprintf (dump_file, "(classify_chrec "); | |
ef6cb4c7 | 2971 | print_generic_expr (dump_file, chrec); |
9baba81b SP |
2972 | fprintf (dump_file, "\n"); |
2973 | } | |
b8698a0f | 2974 | |
9baba81b | 2975 | stats->nb_chrecs++; |
b8698a0f | 2976 | |
9baba81b SP |
2977 | if (chrec == NULL_TREE) |
2978 | { | |
2979 | stats->nb_undetermined++; | |
2980 | return; | |
2981 | } | |
b8698a0f | 2982 | |
9baba81b SP |
2983 | switch (TREE_CODE (chrec)) |
2984 | { | |
2985 | case POLYNOMIAL_CHREC: | |
2986 | if (evolution_function_is_affine_p (chrec)) | |
2987 | { | |
2988 | if (dump_file && (dump_flags & TDF_STATS)) | |
2989 | fprintf (dump_file, " affine_univariate\n"); | |
2990 | stats->nb_affine++; | |
2991 | } | |
a50411de | 2992 | else if (evolution_function_is_affine_multivariate_p (chrec, 0)) |
9baba81b SP |
2993 | { |
2994 | if (dump_file && (dump_flags & TDF_STATS)) | |
2995 | fprintf (dump_file, " affine_multivariate\n"); | |
2996 | stats->nb_affine_multivar++; | |
2997 | } | |
2998 | else | |
2999 | { | |
3000 | if (dump_file && (dump_flags & TDF_STATS)) | |
3001 | fprintf (dump_file, " higher_degree_polynomial\n"); | |
3002 | stats->nb_higher_poly++; | |
3003 | } | |
b8698a0f | 3004 | |
9baba81b SP |
3005 | break; |
3006 | ||
3007 | default: | |
3008 | break; | |
3009 | } | |
b8698a0f | 3010 | |
9baba81b SP |
3011 | if (chrec_contains_undetermined (chrec)) |
3012 | { | |
3013 | if (dump_file && (dump_flags & TDF_STATS)) | |
3014 | fprintf (dump_file, " undetermined\n"); | |
3015 | stats->nb_undetermined++; | |
3016 | } | |
b8698a0f | 3017 | |
9baba81b SP |
3018 | if (dump_file && (dump_flags & TDF_STATS)) |
3019 | fprintf (dump_file, ")\n"); | |
3020 | } | |
3021 | ||
9baba81b SP |
3022 | /* Classify the chrecs of the whole database. */ |
3023 | ||
b8698a0f | 3024 | void |
9baba81b SP |
3025 | gather_stats_on_scev_database (void) |
3026 | { | |
3027 | struct chrec_stats stats; | |
b8698a0f | 3028 | |
9baba81b SP |
3029 | if (!dump_file) |
3030 | return; | |
b8698a0f | 3031 | |
9baba81b | 3032 | reset_chrecs_counters (&stats); |
b8698a0f | 3033 | |
907dadbd TS |
3034 | hash_table<scev_info_hasher>::iterator iter; |
3035 | scev_info_str *elt; | |
3036 | FOR_EACH_HASH_TABLE_ELEMENT (*scalar_evolution_info, elt, scev_info_str *, | |
3037 | iter) | |
3038 | gather_chrec_stats (elt->chrec, &stats); | |
9baba81b SP |
3039 | |
3040 | dump_chrecs_stats (dump_file, &stats); | |
3041 | } | |
3042 | ||
3043 | \f | |
9baba81b SP |
3044 | /* Initialize the analysis of scalar evolutions for LOOPS. */ |
3045 | ||
3046 | void | |
d73be268 | 3047 | scev_initialize (void) |
9baba81b | 3048 | { |
42fd6772 | 3049 | struct loop *loop; |
9baba81b | 3050 | |
fb1fe1f3 RB |
3051 | gcc_assert (! scev_initialized_p ()); |
3052 | ||
907dadbd | 3053 | scalar_evolution_info = hash_table<scev_info_hasher>::create_ggc (100); |
b8698a0f | 3054 | |
f0bd40b1 | 3055 | FOR_EACH_LOOP (loop, 0) |
42fd6772 ZD |
3056 | { |
3057 | loop->nb_iterations = NULL_TREE; | |
3058 | } | |
9baba81b SP |
3059 | } |
3060 | ||
e3a8f1fa JH |
3061 | /* Return true if SCEV is initialized. */ |
3062 | ||
3063 | bool | |
3064 | scev_initialized_p (void) | |
3065 | { | |
3066 | return scalar_evolution_info != NULL; | |
3067 | } | |
3068 | ||
a7bf45de SP |
3069 | /* Cleans up the information cached by the scalar evolutions analysis |
3070 | in the hash table. */ | |
3071 | ||
3072 | void | |
3073 | scev_reset_htab (void) | |
3074 | { | |
3075 | if (!scalar_evolution_info) | |
3076 | return; | |
3077 | ||
907dadbd | 3078 | scalar_evolution_info->empty (); |
a7bf45de SP |
3079 | } |
3080 | ||
3081 | /* Cleans up the information cached by the scalar evolutions analysis | |
3082 | in the hash table and in the loop->nb_iterations. */ | |
9baba81b SP |
3083 | |
3084 | void | |
3085 | scev_reset (void) | |
3086 | { | |
9baba81b SP |
3087 | struct loop *loop; |
3088 | ||
a7bf45de SP |
3089 | scev_reset_htab (); |
3090 | ||
f0bd40b1 | 3091 | FOR_EACH_LOOP (loop, 0) |
9baba81b | 3092 | { |
42fd6772 | 3093 | loop->nb_iterations = NULL_TREE; |
9baba81b | 3094 | } |
e9eb809d ZD |
3095 | } |
3096 | ||
1e3d54b4 JH |
3097 | /* Return true if the IV calculation in TYPE can overflow based on the knowledge |
3098 | of the upper bound on the number of iterations of LOOP, the BASE and STEP | |
3099 | of IV. | |
3100 | ||
3101 | We do not use information whether TYPE can overflow so it is safe to | |
3102 | use this test even for derived IVs not computed every iteration or | |
3103 | hypotetical IVs to be inserted into code. */ | |
3104 | ||
019d6598 | 3105 | bool |
1e3d54b4 JH |
3106 | iv_can_overflow_p (struct loop *loop, tree type, tree base, tree step) |
3107 | { | |
3108 | widest_int nit; | |
3109 | wide_int base_min, base_max, step_min, step_max, type_min, type_max; | |
3110 | signop sgn = TYPE_SIGN (type); | |
3111 | ||
3112 | if (integer_zerop (step)) | |
3113 | return false; | |
3114 | ||
3115 | if (TREE_CODE (base) == INTEGER_CST) | |
8e6cdc90 | 3116 | base_min = base_max = wi::to_wide (base); |
1e3d54b4 JH |
3117 | else if (TREE_CODE (base) == SSA_NAME |
3118 | && INTEGRAL_TYPE_P (TREE_TYPE (base)) | |
3119 | && get_range_info (base, &base_min, &base_max) == VR_RANGE) | |
3120 | ; | |
3121 | else | |
3122 | return true; | |
3123 | ||
3124 | if (TREE_CODE (step) == INTEGER_CST) | |
8e6cdc90 | 3125 | step_min = step_max = wi::to_wide (step); |
1e3d54b4 JH |
3126 | else if (TREE_CODE (step) == SSA_NAME |
3127 | && INTEGRAL_TYPE_P (TREE_TYPE (step)) | |
3128 | && get_range_info (step, &step_min, &step_max) == VR_RANGE) | |
3129 | ; | |
3130 | else | |
3131 | return true; | |
3132 | ||
3133 | if (!get_max_loop_iterations (loop, &nit)) | |
3134 | return true; | |
3135 | ||
3136 | type_min = wi::min_value (type); | |
3137 | type_max = wi::max_value (type); | |
3138 | ||
3139 | /* Just sanity check that we don't see values out of the range of the type. | |
3140 | In this case the arithmetics bellow would overflow. */ | |
3141 | gcc_checking_assert (wi::ge_p (base_min, type_min, sgn) | |
3142 | && wi::le_p (base_max, type_max, sgn)); | |
3143 | ||
3144 | /* Account the possible increment in the last ieration. */ | |
4a669ac3 | 3145 | wi::overflow_type overflow = wi::OVF_NONE; |
1e3d54b4 JH |
3146 | nit = wi::add (nit, 1, SIGNED, &overflow); |
3147 | if (overflow) | |
3148 | return true; | |
3149 | ||
3150 | /* NIT is typeless and can exceed the precision of the type. In this case | |
3151 | overflow is always possible, because we know STEP is non-zero. */ | |
3152 | if (wi::min_precision (nit, UNSIGNED) > TYPE_PRECISION (type)) | |
3153 | return true; | |
3154 | wide_int nit2 = wide_int::from (nit, TYPE_PRECISION (type), UNSIGNED); | |
3155 | ||
3156 | /* If step can be positive, check that nit*step <= type_max-base. | |
3157 | This can be done by unsigned arithmetic and we only need to watch overflow | |
3158 | in the multiplication. The right hand side can always be represented in | |
3159 | the type. */ | |
3160 | if (sgn == UNSIGNED || !wi::neg_p (step_max)) | |
3161 | { | |
4a669ac3 | 3162 | wi::overflow_type overflow = wi::OVF_NONE; |
1e3d54b4 JH |
3163 | if (wi::gtu_p (wi::mul (step_max, nit2, UNSIGNED, &overflow), |
3164 | type_max - base_max) | |
3165 | || overflow) | |
3166 | return true; | |
3167 | } | |
3168 | /* If step can be negative, check that nit*(-step) <= base_min-type_min. */ | |
3169 | if (sgn == SIGNED && wi::neg_p (step_min)) | |
3170 | { | |
4a669ac3 AH |
3171 | wi::overflow_type overflow, overflow2; |
3172 | overflow = overflow2 = wi::OVF_NONE; | |
1e3d54b4 JH |
3173 | if (wi::gtu_p (wi::mul (wi::neg (step_min, &overflow2), |
3174 | nit2, UNSIGNED, &overflow), | |
3175 | base_min - type_min) | |
3176 | || overflow || overflow2) | |
3177 | return true; | |
3178 | } | |
3179 | ||
3180 | return false; | |
3181 | } | |
3182 | ||
43aabfcf BC |
3183 | /* Given EV with form of "(type) {inner_base, inner_step}_loop", this |
3184 | function tries to derive condition under which it can be simplified | |
3185 | into "{(type)inner_base, (type)inner_step}_loop". The condition is | |
3186 | the maximum number that inner iv can iterate. */ | |
3187 | ||
3188 | static tree | |
3189 | derive_simple_iv_with_niters (tree ev, tree *niters) | |
3190 | { | |
3191 | if (!CONVERT_EXPR_P (ev)) | |
3192 | return ev; | |
3193 | ||
3194 | tree inner_ev = TREE_OPERAND (ev, 0); | |
3195 | if (TREE_CODE (inner_ev) != POLYNOMIAL_CHREC) | |
3196 | return ev; | |
3197 | ||
3198 | tree init = CHREC_LEFT (inner_ev); | |
3199 | tree step = CHREC_RIGHT (inner_ev); | |
3200 | if (TREE_CODE (init) != INTEGER_CST | |
3201 | || TREE_CODE (step) != INTEGER_CST || integer_zerop (step)) | |
3202 | return ev; | |
3203 | ||
3204 | tree type = TREE_TYPE (ev); | |
3205 | tree inner_type = TREE_TYPE (inner_ev); | |
3206 | if (TYPE_PRECISION (inner_type) >= TYPE_PRECISION (type)) | |
3207 | return ev; | |
3208 | ||
3209 | /* Type conversion in "(type) {inner_base, inner_step}_loop" can be | |
3210 | folded only if inner iv won't overflow. We compute the maximum | |
3211 | number the inner iv can iterate before overflowing and return the | |
3212 | simplified affine iv. */ | |
3213 | tree delta; | |
3214 | init = fold_convert (type, init); | |
3215 | step = fold_convert (type, step); | |
3216 | ev = build_polynomial_chrec (CHREC_VARIABLE (inner_ev), init, step); | |
3217 | if (tree_int_cst_sign_bit (step)) | |
3218 | { | |
3219 | tree bound = lower_bound_in_type (inner_type, inner_type); | |
3220 | delta = fold_build2 (MINUS_EXPR, type, init, fold_convert (type, bound)); | |
3221 | step = fold_build1 (NEGATE_EXPR, type, step); | |
3222 | } | |
3223 | else | |
3224 | { | |
3225 | tree bound = upper_bound_in_type (inner_type, inner_type); | |
3226 | delta = fold_build2 (MINUS_EXPR, type, fold_convert (type, bound), init); | |
3227 | } | |
3228 | *niters = fold_build2 (FLOOR_DIV_EXPR, type, delta, step); | |
3229 | return ev; | |
3230 | } | |
3231 | ||
f017bf5e ZD |
3232 | /* Checks whether use of OP in USE_LOOP behaves as a simple affine iv with |
3233 | respect to WRTO_LOOP and returns its base and step in IV if possible | |
3234 | (see analyze_scalar_evolution_in_loop for more details on USE_LOOP | |
3235 | and WRTO_LOOP). If ALLOW_NONCONSTANT_STEP is true, we want step to be | |
3236 | invariant in LOOP. Otherwise we require it to be an integer constant. | |
b8698a0f | 3237 | |
f017bf5e ZD |
3238 | IV->no_overflow is set to true if we are sure the iv cannot overflow (e.g. |
3239 | because it is computed in signed arithmetics). Consequently, adding an | |
3240 | induction variable | |
b8698a0f | 3241 | |
f017bf5e ZD |
3242 | for (i = IV->base; ; i += IV->step) |
3243 | ||
3244 | is only safe if IV->no_overflow is false, or TYPE_OVERFLOW_UNDEFINED is | |
3245 | false for the type of the induction variable, or you can prove that i does | |
3246 | not wrap by some other argument. Otherwise, this might introduce undefined | |
3247 | behavior, and | |
b8698a0f | 3248 | |
43aabfcf BC |
3249 | i = iv->base; |
3250 | for (; ; i = (type) ((unsigned type) i + (unsigned type) iv->step)) | |
3251 | ||
3252 | must be used instead. | |
3253 | ||
3254 | When IV_NITERS is not NULL, this function also checks case in which OP | |
3255 | is a conversion of an inner simple iv of below form: | |
3256 | ||
3257 | (outer_type){inner_base, inner_step}_loop. | |
f017bf5e | 3258 | |
43aabfcf BC |
3259 | If type of inner iv has smaller precision than outer_type, it can't be |
3260 | folded into {(outer_type)inner_base, (outer_type)inner_step}_loop because | |
3261 | the inner iv could overflow/wrap. In this case, we derive a condition | |
3262 | under which the inner iv won't overflow/wrap and do the simplification. | |
3263 | The derived condition normally is the maximum number the inner iv can | |
3264 | iterate, and will be stored in IV_NITERS. This is useful in loop niter | |
3265 | analysis, to derive break conditions when a loop must terminate, when is | |
3266 | infinite. */ | |
e9eb809d ZD |
3267 | |
3268 | bool | |
43aabfcf BC |
3269 | simple_iv_with_niters (struct loop *wrto_loop, struct loop *use_loop, |
3270 | tree op, affine_iv *iv, tree *iv_niters, | |
3271 | bool allow_nonconstant_step) | |
e9eb809d | 3272 | { |
f3c5f3a3 | 3273 | enum tree_code code; |
8aa46dd2 | 3274 | tree type, ev, base, e; |
f3c5f3a3 | 3275 | wide_int extreme; |
4a669ac3 | 3276 | bool folded_casts; |
9baba81b | 3277 | |
a6f778b2 ZD |
3278 | iv->base = NULL_TREE; |
3279 | iv->step = NULL_TREE; | |
3280 | iv->no_overflow = false; | |
9baba81b SP |
3281 | |
3282 | type = TREE_TYPE (op); | |
1ee0d660 EB |
3283 | if (!POINTER_TYPE_P (type) |
3284 | && !INTEGRAL_TYPE_P (type)) | |
9baba81b SP |
3285 | return false; |
3286 | ||
f017bf5e | 3287 | ev = analyze_scalar_evolution_in_loop (wrto_loop, use_loop, op, |
a6f778b2 | 3288 | &folded_casts); |
f017bf5e ZD |
3289 | if (chrec_contains_undetermined (ev) |
3290 | || chrec_contains_symbols_defined_in_loop (ev, wrto_loop->num)) | |
9baba81b SP |
3291 | return false; |
3292 | ||
f017bf5e | 3293 | if (tree_does_not_contain_chrecs (ev)) |
9baba81b | 3294 | { |
a6f778b2 | 3295 | iv->base = ev; |
6e42ce54 | 3296 | iv->step = build_int_cst (TREE_TYPE (ev), 0); |
a6f778b2 | 3297 | iv->no_overflow = true; |
9baba81b SP |
3298 | return true; |
3299 | } | |
3300 | ||
43aabfcf BC |
3301 | /* If we can derive valid scalar evolution with assumptions. */ |
3302 | if (iv_niters && TREE_CODE (ev) != POLYNOMIAL_CHREC) | |
3303 | ev = derive_simple_iv_with_niters (ev, iv_niters); | |
3304 | ||
3305 | if (TREE_CODE (ev) != POLYNOMIAL_CHREC) | |
3306 | return false; | |
3307 | ||
3308 | if (CHREC_VARIABLE (ev) != (unsigned) wrto_loop->num) | |
9baba81b SP |
3309 | return false; |
3310 | ||
a6f778b2 | 3311 | iv->step = CHREC_RIGHT (ev); |
f017bf5e ZD |
3312 | if ((!allow_nonconstant_step && TREE_CODE (iv->step) != INTEGER_CST) |
3313 | || tree_contains_chrecs (iv->step, NULL)) | |
9baba81b | 3314 | return false; |
9be872b7 | 3315 | |
a6f778b2 | 3316 | iv->base = CHREC_LEFT (ev); |
f017bf5e | 3317 | if (tree_contains_chrecs (iv->base, NULL)) |
9baba81b SP |
3318 | return false; |
3319 | ||
1210573b | 3320 | iv->no_overflow = !folded_casts && nowrap_type_p (type); |
eeef0e45 | 3321 | |
1e3d54b4 JH |
3322 | if (!iv->no_overflow |
3323 | && !iv_can_overflow_p (wrto_loop, type, iv->base, iv->step)) | |
3324 | iv->no_overflow = true; | |
3325 | ||
f3c5f3a3 BC |
3326 | /* Try to simplify iv base: |
3327 | ||
3328 | (signed T) ((unsigned T)base + step) ;; TREE_TYPE (base) == signed T | |
3329 | == (signed T)(unsigned T)base + step | |
3330 | == base + step | |
3331 | ||
3332 | If we can prove operation (base + step) doesn't overflow or underflow. | |
3333 | Specifically, we try to prove below conditions are satisfied: | |
3334 | ||
3335 | base <= UPPER_BOUND (type) - step ;;step > 0 | |
3336 | base >= LOWER_BOUND (type) - step ;;step < 0 | |
3337 | ||
3338 | This is done by proving the reverse conditions are false using loop's | |
3339 | initial conditions. | |
3340 | ||
3341 | The is necessary to make loop niter, or iv overflow analysis easier | |
3342 | for below example: | |
3343 | ||
3344 | int foo (int *a, signed char s, signed char l) | |
3345 | { | |
3346 | signed char i; | |
3347 | for (i = s; i < l; i++) | |
3348 | a[i] = 0; | |
3349 | return 0; | |
3350 | } | |
3351 | ||
3352 | Note variable I is firstly converted to type unsigned char, incremented, | |
3353 | then converted back to type signed char. */ | |
3354 | ||
3355 | if (wrto_loop->num != use_loop->num) | |
3356 | return true; | |
3357 | ||
3358 | if (!CONVERT_EXPR_P (iv->base) || TREE_CODE (iv->step) != INTEGER_CST) | |
3359 | return true; | |
3360 | ||
3361 | type = TREE_TYPE (iv->base); | |
3362 | e = TREE_OPERAND (iv->base, 0); | |
3363 | if (TREE_CODE (e) != PLUS_EXPR | |
3364 | || TREE_CODE (TREE_OPERAND (e, 1)) != INTEGER_CST | |
3365 | || !tree_int_cst_equal (iv->step, | |
3366 | fold_convert (type, TREE_OPERAND (e, 1)))) | |
3367 | return true; | |
3368 | e = TREE_OPERAND (e, 0); | |
3369 | if (!CONVERT_EXPR_P (e)) | |
3370 | return true; | |
3371 | base = TREE_OPERAND (e, 0); | |
3372 | if (!useless_type_conversion_p (type, TREE_TYPE (base))) | |
3373 | return true; | |
3374 | ||
3375 | if (tree_int_cst_sign_bit (iv->step)) | |
3376 | { | |
3377 | code = LT_EXPR; | |
3378 | extreme = wi::min_value (type); | |
3379 | } | |
3380 | else | |
3381 | { | |
3382 | code = GT_EXPR; | |
3383 | extreme = wi::max_value (type); | |
3384 | } | |
4a669ac3 | 3385 | wi::overflow_type overflow = wi::OVF_NONE; |
8e6cdc90 RS |
3386 | extreme = wi::sub (extreme, wi::to_wide (iv->step), |
3387 | TYPE_SIGN (type), &overflow); | |
f3c5f3a3 BC |
3388 | if (overflow) |
3389 | return true; | |
3390 | e = fold_build2 (code, boolean_type_node, base, | |
3391 | wide_int_to_tree (type, extreme)); | |
8aa46dd2 | 3392 | e = simplify_using_initial_conditions (use_loop, e); |
f3c5f3a3 BC |
3393 | if (!integer_zerop (e)) |
3394 | return true; | |
3395 | ||
3396 | if (POINTER_TYPE_P (TREE_TYPE (base))) | |
3397 | code = POINTER_PLUS_EXPR; | |
3398 | else | |
3399 | code = PLUS_EXPR; | |
3400 | ||
3401 | iv->base = fold_build2 (code, TREE_TYPE (base), base, iv->step); | |
9baba81b SP |
3402 | return true; |
3403 | } | |
3404 | ||
43aabfcf BC |
3405 | /* Like simple_iv_with_niters, but return TRUE when OP behaves as a simple |
3406 | affine iv unconditionally. */ | |
3407 | ||
3408 | bool | |
3409 | simple_iv (struct loop *wrto_loop, struct loop *use_loop, tree op, | |
3410 | affine_iv *iv, bool allow_nonconstant_step) | |
3411 | { | |
3412 | return simple_iv_with_niters (wrto_loop, use_loop, op, iv, | |
3413 | NULL, allow_nonconstant_step); | |
3414 | } | |
3415 | ||
9baba81b SP |
3416 | /* Finalize the scalar evolution analysis. */ |
3417 | ||
3418 | void | |
3419 | scev_finalize (void) | |
3420 | { | |
d51157de ZD |
3421 | if (!scalar_evolution_info) |
3422 | return; | |
907dadbd | 3423 | scalar_evolution_info->empty (); |
c7b852c8 | 3424 | scalar_evolution_info = NULL; |
01f1c24e | 3425 | free_numbers_of_iterations_estimates (cfun); |
9baba81b SP |
3426 | } |
3427 | ||
771f882e ZD |
3428 | /* Returns true if the expression EXPR is considered to be too expensive |
3429 | for scev_const_prop. */ | |
3430 | ||
5fd8a9cb RB |
3431 | static bool |
3432 | expression_expensive_p (tree expr, hash_map<tree, uint64_t> &cache, | |
3433 | uint64_t &cost) | |
771f882e ZD |
3434 | { |
3435 | enum tree_code code; | |
3436 | ||
3437 | if (is_gimple_val (expr)) | |
3438 | return false; | |
3439 | ||
3440 | code = TREE_CODE (expr); | |
3441 | if (code == TRUNC_DIV_EXPR | |
3442 | || code == CEIL_DIV_EXPR | |
3443 | || code == FLOOR_DIV_EXPR | |
3444 | || code == ROUND_DIV_EXPR | |
3445 | || code == TRUNC_MOD_EXPR | |
3446 | || code == CEIL_MOD_EXPR | |
3447 | || code == FLOOR_MOD_EXPR | |
3448 | || code == ROUND_MOD_EXPR | |
3449 | || code == EXACT_DIV_EXPR) | |
3450 | { | |
3451 | /* Division by power of two is usually cheap, so we allow it. | |
3452 | Forbid anything else. */ | |
3453 | if (!integer_pow2p (TREE_OPERAND (expr, 1))) | |
3454 | return true; | |
3455 | } | |
3456 | ||
5fd8a9cb RB |
3457 | bool visited_p; |
3458 | uint64_t &local_cost = cache.get_or_insert (expr, &visited_p); | |
3459 | if (visited_p) | |
3460 | { | |
3461 | uint64_t tem = cost + local_cost; | |
3462 | if (tem < cost) | |
3463 | return true; | |
3464 | cost = tem; | |
3465 | return false; | |
3466 | } | |
3467 | local_cost = 1; | |
3468 | ||
3469 | uint64_t op_cost = 0; | |
5126ae0c KV |
3470 | if (code == CALL_EXPR) |
3471 | { | |
3472 | tree arg; | |
3473 | call_expr_arg_iterator iter; | |
06a6b46a KV |
3474 | /* Even though is_inexpensive_builtin might say true, we will get a |
3475 | library call for popcount when backend does not have an instruction | |
3476 | to do so. We consider this to be expenseive and generate | |
3477 | __builtin_popcount only when backend defines it. */ | |
3478 | combined_fn cfn = get_call_combined_fn (expr); | |
3479 | switch (cfn) | |
3480 | { | |
3481 | CASE_CFN_POPCOUNT: | |
3482 | /* Check if opcode for popcount is available in the mode required. */ | |
3483 | if (optab_handler (popcount_optab, | |
3484 | TYPE_MODE (TREE_TYPE (CALL_EXPR_ARG (expr, 0)))) | |
3485 | == CODE_FOR_nothing) | |
3486 | { | |
3487 | machine_mode mode; | |
3488 | mode = TYPE_MODE (TREE_TYPE (CALL_EXPR_ARG (expr, 0))); | |
3489 | scalar_int_mode int_mode; | |
3490 | ||
3491 | /* If the mode is of 2 * UNITS_PER_WORD size, we can handle | |
3492 | double-word popcount by emitting two single-word popcount | |
3493 | instructions. */ | |
3494 | if (is_a <scalar_int_mode> (mode, &int_mode) | |
3495 | && GET_MODE_SIZE (int_mode) == 2 * UNITS_PER_WORD | |
3496 | && (optab_handler (popcount_optab, word_mode) | |
3497 | != CODE_FOR_nothing)) | |
3498 | break; | |
3499 | return true; | |
3500 | } | |
3501 | default: | |
3502 | break; | |
3503 | } | |
5126ae0c KV |
3504 | |
3505 | if (!is_inexpensive_builtin (get_callee_fndecl (expr))) | |
3506 | return true; | |
3507 | FOR_EACH_CALL_EXPR_ARG (arg, iter, expr) | |
5fd8a9cb | 3508 | if (expression_expensive_p (arg, cache, op_cost)) |
5126ae0c | 3509 | return true; |
5fd8a9cb RB |
3510 | *cache.get (expr) += op_cost; |
3511 | cost += op_cost + 1; | |
5126ae0c KV |
3512 | return false; |
3513 | } | |
3514 | ||
3f6f3319 | 3515 | if (code == COND_EXPR) |
5fd8a9cb RB |
3516 | { |
3517 | if (expression_expensive_p (TREE_OPERAND (expr, 0), cache, op_cost) | |
3518 | || (EXPR_P (TREE_OPERAND (expr, 1)) | |
3519 | && EXPR_P (TREE_OPERAND (expr, 2))) | |
3520 | /* If either branch has side effects or could trap. */ | |
3521 | || TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1)) | |
3522 | || generic_expr_could_trap_p (TREE_OPERAND (expr, 1)) | |
3523 | || TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 0)) | |
3524 | || generic_expr_could_trap_p (TREE_OPERAND (expr, 0)) | |
3525 | || expression_expensive_p (TREE_OPERAND (expr, 1), | |
3526 | cache, op_cost) | |
3527 | || expression_expensive_p (TREE_OPERAND (expr, 2), | |
3528 | cache, op_cost)) | |
3529 | return true; | |
3530 | *cache.get (expr) += op_cost; | |
3531 | cost += op_cost + 1; | |
3532 | return false; | |
3533 | } | |
3f6f3319 | 3534 | |
771f882e ZD |
3535 | switch (TREE_CODE_CLASS (code)) |
3536 | { | |
3537 | case tcc_binary: | |
3538 | case tcc_comparison: | |
5fd8a9cb | 3539 | if (expression_expensive_p (TREE_OPERAND (expr, 1), cache, op_cost)) |
771f882e ZD |
3540 | return true; |
3541 | ||
3542 | /* Fallthru. */ | |
3543 | case tcc_unary: | |
5fd8a9cb RB |
3544 | if (expression_expensive_p (TREE_OPERAND (expr, 0), cache, op_cost)) |
3545 | return true; | |
3546 | *cache.get (expr) += op_cost; | |
3547 | cost += op_cost + 1; | |
3548 | return false; | |
771f882e ZD |
3549 | |
3550 | default: | |
3551 | return true; | |
3552 | } | |
3553 | } | |
3554 | ||
5fd8a9cb RB |
3555 | bool |
3556 | expression_expensive_p (tree expr) | |
3557 | { | |
3558 | hash_map<tree, uint64_t> cache; | |
3559 | uint64_t expanded_size = 0; | |
3560 | return (expression_expensive_p (expr, cache, expanded_size) | |
3561 | || expanded_size > cache.elements ()); | |
3562 | } | |
3563 | ||
4cc31a3c | 3564 | /* Do final value replacement for LOOP, return true if we did anything. */ |
f993a853 | 3565 | |
4cc31a3c | 3566 | bool |
f993a853 TV |
3567 | final_value_replacement_loop (struct loop *loop) |
3568 | { | |
3569 | /* If we do not know exact number of iterations of the loop, we cannot | |
3570 | replace the final value. */ | |
3571 | edge exit = single_exit (loop); | |
3572 | if (!exit) | |
4cc31a3c | 3573 | return false; |
f993a853 TV |
3574 | |
3575 | tree niter = number_of_latch_executions (loop); | |
3576 | if (niter == chrec_dont_know) | |
4cc31a3c | 3577 | return false; |
f993a853 TV |
3578 | |
3579 | /* Ensure that it is possible to insert new statements somewhere. */ | |
3580 | if (!single_pred_p (exit->dest)) | |
3581 | split_loop_exit_edge (exit); | |
3582 | ||
3583 | /* Set stmt insertion pointer. All stmts are inserted before this point. */ | |
3584 | gimple_stmt_iterator gsi = gsi_after_labels (exit->dest); | |
3585 | ||
3586 | struct loop *ex_loop | |
3587 | = superloop_at_depth (loop, | |
3588 | loop_depth (exit->dest->loop_father) + 1); | |
3589 | ||
4cc31a3c | 3590 | bool any = false; |
f993a853 TV |
3591 | gphi_iterator psi; |
3592 | for (psi = gsi_start_phis (exit->dest); !gsi_end_p (psi); ) | |
3593 | { | |
3594 | gphi *phi = psi.phi (); | |
3595 | tree rslt = PHI_RESULT (phi); | |
3596 | tree def = PHI_ARG_DEF_FROM_EDGE (phi, exit); | |
3597 | if (virtual_operand_p (def)) | |
3598 | { | |
3599 | gsi_next (&psi); | |
3600 | continue; | |
3601 | } | |
3602 | ||
3603 | if (!POINTER_TYPE_P (TREE_TYPE (def)) | |
3604 | && !INTEGRAL_TYPE_P (TREE_TYPE (def))) | |
3605 | { | |
3606 | gsi_next (&psi); | |
3607 | continue; | |
3608 | } | |
3609 | ||
3610 | bool folded_casts; | |
3611 | def = analyze_scalar_evolution_in_loop (ex_loop, loop, def, | |
3612 | &folded_casts); | |
3613 | def = compute_overall_effect_of_inner_loop (ex_loop, def); | |
3614 | if (!tree_does_not_contain_chrecs (def) | |
3615 | || chrec_contains_symbols_defined_in_loop (def, ex_loop->num) | |
3616 | /* Moving the computation from the loop may prolong life range | |
3617 | of some ssa names, which may cause problems if they appear | |
3618 | on abnormal edges. */ | |
3619 | || contains_abnormal_ssa_name_p (def) | |
3620 | /* Do not emit expensive expressions. The rationale is that | |
3621 | when someone writes a code like | |
3622 | ||
3623 | while (n > 45) n -= 45; | |
3624 | ||
3625 | he probably knows that n is not large, and does not want it | |
3626 | to be turned into n %= 45. */ | |
3627 | || expression_expensive_p (def)) | |
3628 | { | |
3629 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3630 | { | |
3631 | fprintf (dump_file, "not replacing:\n "); | |
ef6cb4c7 | 3632 | print_gimple_stmt (dump_file, phi, 0); |
f993a853 TV |
3633 | fprintf (dump_file, "\n"); |
3634 | } | |
3635 | gsi_next (&psi); | |
3636 | continue; | |
3637 | } | |
3638 | ||
3639 | /* Eliminate the PHI node and replace it by a computation outside | |
3640 | the loop. */ | |
3641 | if (dump_file) | |
3642 | { | |
3643 | fprintf (dump_file, "\nfinal value replacement:\n "); | |
ef6cb4c7 | 3644 | print_gimple_stmt (dump_file, phi, 0); |
47a5f7dd AM |
3645 | fprintf (dump_file, " with expr: "); |
3646 | print_generic_expr (dump_file, def); | |
f993a853 | 3647 | } |
4cc31a3c | 3648 | any = true; |
f993a853 TV |
3649 | def = unshare_expr (def); |
3650 | remove_phi_node (&psi, false); | |
3651 | ||
3652 | /* If def's type has undefined overflow and there were folded | |
3653 | casts, rewrite all stmts added for def into arithmetics | |
3654 | with defined overflow behavior. */ | |
3655 | if (folded_casts && ANY_INTEGRAL_TYPE_P (TREE_TYPE (def)) | |
3656 | && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (def))) | |
3657 | { | |
3658 | gimple_seq stmts; | |
3659 | gimple_stmt_iterator gsi2; | |
3660 | def = force_gimple_operand (def, &stmts, true, NULL_TREE); | |
3661 | gsi2 = gsi_start (stmts); | |
3662 | while (!gsi_end_p (gsi2)) | |
3663 | { | |
3664 | gimple *stmt = gsi_stmt (gsi2); | |
3665 | gimple_stmt_iterator gsi3 = gsi2; | |
3666 | gsi_next (&gsi2); | |
3667 | gsi_remove (&gsi3, false); | |
3668 | if (is_gimple_assign (stmt) | |
3669 | && arith_code_with_undefined_signed_overflow | |
3670 | (gimple_assign_rhs_code (stmt))) | |
3671 | gsi_insert_seq_before (&gsi, | |
3672 | rewrite_to_defined_overflow (stmt), | |
3673 | GSI_SAME_STMT); | |
3674 | else | |
3675 | gsi_insert_before (&gsi, stmt, GSI_SAME_STMT); | |
3676 | } | |
3677 | } | |
3678 | else | |
3679 | def = force_gimple_operand_gsi (&gsi, def, false, NULL_TREE, | |
3680 | true, GSI_SAME_STMT); | |
3681 | ||
3682 | gassign *ass = gimple_build_assign (rslt, def); | |
ffdc40a9 EB |
3683 | gimple_set_location (ass, |
3684 | gimple_phi_arg_location (phi, exit->dest_idx)); | |
f993a853 TV |
3685 | gsi_insert_before (&gsi, ass, GSI_SAME_STMT); |
3686 | if (dump_file) | |
3687 | { | |
47a5f7dd | 3688 | fprintf (dump_file, "\n final stmt:\n "); |
ef6cb4c7 | 3689 | print_gimple_stmt (dump_file, ass, 0); |
f993a853 TV |
3690 | fprintf (dump_file, "\n"); |
3691 | } | |
3692 | } | |
925196ed | 3693 | |
4cc31a3c | 3694 | return any; |
684aaf29 | 3695 | } |
9e2f83a5 ZD |
3696 | |
3697 | #include "gt-tree-scalar-evolution.h" |