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4ee9c684 | 1 | /* Conditional constant propagation pass for the GNU compiler. |
535664e3 | 2 | Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006 |
000657b5 | 3 | Free Software Foundation, Inc. |
4ee9c684 | 4 | Adapted from original RTL SSA-CCP by Daniel Berlin <dberlin@dberlin.org> |
5 | Adapted to GIMPLE trees by Diego Novillo <dnovillo@redhat.com> | |
6 | ||
7 | This file is part of GCC. | |
8 | ||
9 | GCC is free software; you can redistribute it and/or modify it | |
10 | under the terms of the GNU General Public License as published by the | |
11 | Free Software Foundation; either version 2, or (at your option) any | |
12 | later version. | |
13 | ||
14 | GCC is distributed in the hope that it will be useful, but WITHOUT | |
15 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
16 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
17 | for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
20 | along with GCC; see the file COPYING. If not, write to the Free | |
67ce556b | 21 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA |
22 | 02110-1301, USA. */ | |
4ee9c684 | 23 | |
88dbf20f | 24 | /* Conditional constant propagation (CCP) is based on the SSA |
25 | propagation engine (tree-ssa-propagate.c). Constant assignments of | |
26 | the form VAR = CST are propagated from the assignments into uses of | |
27 | VAR, which in turn may generate new constants. The simulation uses | |
28 | a four level lattice to keep track of constant values associated | |
29 | with SSA names. Given an SSA name V_i, it may take one of the | |
30 | following values: | |
31 | ||
bfa30570 | 32 | UNINITIALIZED -> the initial state of the value. This value |
33 | is replaced with a correct initial value | |
34 | the first time the value is used, so the | |
35 | rest of the pass does not need to care about | |
36 | it. Using this value simplifies initialization | |
37 | of the pass, and prevents us from needlessly | |
38 | scanning statements that are never reached. | |
88dbf20f | 39 | |
40 | UNDEFINED -> V_i is a local variable whose definition | |
41 | has not been processed yet. Therefore we | |
42 | don't yet know if its value is a constant | |
43 | or not. | |
44 | ||
45 | CONSTANT -> V_i has been found to hold a constant | |
46 | value C. | |
47 | ||
48 | VARYING -> V_i cannot take a constant value, or if it | |
49 | does, it is not possible to determine it | |
50 | at compile time. | |
51 | ||
52 | The core of SSA-CCP is in ccp_visit_stmt and ccp_visit_phi_node: | |
53 | ||
54 | 1- In ccp_visit_stmt, we are interested in assignments whose RHS | |
55 | evaluates into a constant and conditional jumps whose predicate | |
56 | evaluates into a boolean true or false. When an assignment of | |
57 | the form V_i = CONST is found, V_i's lattice value is set to | |
58 | CONSTANT and CONST is associated with it. This causes the | |
59 | propagation engine to add all the SSA edges coming out the | |
60 | assignment into the worklists, so that statements that use V_i | |
61 | can be visited. | |
62 | ||
63 | If the statement is a conditional with a constant predicate, we | |
64 | mark the outgoing edges as executable or not executable | |
65 | depending on the predicate's value. This is then used when | |
66 | visiting PHI nodes to know when a PHI argument can be ignored. | |
67 | ||
68 | ||
69 | 2- In ccp_visit_phi_node, if all the PHI arguments evaluate to the | |
70 | same constant C, then the LHS of the PHI is set to C. This | |
71 | evaluation is known as the "meet operation". Since one of the | |
72 | goals of this evaluation is to optimistically return constant | |
73 | values as often as possible, it uses two main short cuts: | |
74 | ||
75 | - If an argument is flowing in through a non-executable edge, it | |
76 | is ignored. This is useful in cases like this: | |
77 | ||
78 | if (PRED) | |
79 | a_9 = 3; | |
80 | else | |
81 | a_10 = 100; | |
82 | a_11 = PHI (a_9, a_10) | |
83 | ||
84 | If PRED is known to always evaluate to false, then we can | |
85 | assume that a_11 will always take its value from a_10, meaning | |
86 | that instead of consider it VARYING (a_9 and a_10 have | |
87 | different values), we can consider it CONSTANT 100. | |
88 | ||
89 | - If an argument has an UNDEFINED value, then it does not affect | |
90 | the outcome of the meet operation. If a variable V_i has an | |
91 | UNDEFINED value, it means that either its defining statement | |
92 | hasn't been visited yet or V_i has no defining statement, in | |
93 | which case the original symbol 'V' is being used | |
94 | uninitialized. Since 'V' is a local variable, the compiler | |
95 | may assume any initial value for it. | |
96 | ||
97 | ||
98 | After propagation, every variable V_i that ends up with a lattice | |
99 | value of CONSTANT will have the associated constant value in the | |
100 | array CONST_VAL[i].VALUE. That is fed into substitute_and_fold for | |
101 | final substitution and folding. | |
102 | ||
103 | ||
104 | Constant propagation in stores and loads (STORE-CCP) | |
105 | ---------------------------------------------------- | |
106 | ||
107 | While CCP has all the logic to propagate constants in GIMPLE | |
108 | registers, it is missing the ability to associate constants with | |
109 | stores and loads (i.e., pointer dereferences, structures and | |
110 | global/aliased variables). We don't keep loads and stores in | |
111 | SSA, but we do build a factored use-def web for them (in the | |
112 | virtual operands). | |
113 | ||
114 | For instance, consider the following code fragment: | |
115 | ||
116 | struct A a; | |
117 | const int B = 42; | |
118 | ||
119 | void foo (int i) | |
120 | { | |
121 | if (i > 10) | |
122 | a.a = 42; | |
123 | else | |
124 | { | |
125 | a.b = 21; | |
126 | a.a = a.b + 21; | |
127 | } | |
128 | ||
129 | if (a.a != B) | |
130 | never_executed (); | |
131 | } | |
132 | ||
133 | We should be able to deduce that the predicate 'a.a != B' is always | |
134 | false. To achieve this, we associate constant values to the SSA | |
135 | names in the V_MAY_DEF and V_MUST_DEF operands for each store. | |
136 | Additionally, since we also glob partial loads/stores with the base | |
137 | symbol, we also keep track of the memory reference where the | |
138 | constant value was stored (in the MEM_REF field of PROP_VALUE_T). | |
139 | For instance, | |
140 | ||
141 | # a_5 = V_MAY_DEF <a_4> | |
142 | a.a = 2; | |
143 | ||
144 | # VUSE <a_5> | |
145 | x_3 = a.b; | |
146 | ||
147 | In the example above, CCP will associate value '2' with 'a_5', but | |
148 | it would be wrong to replace the load from 'a.b' with '2', because | |
149 | '2' had been stored into a.a. | |
150 | ||
bfa30570 | 151 | Note that the initial value of virtual operands is VARYING, not |
152 | UNDEFINED. Consider, for instance global variables: | |
88dbf20f | 153 | |
154 | int A; | |
155 | ||
156 | foo (int i) | |
157 | { | |
158 | if (i_3 > 10) | |
159 | A_4 = 3; | |
160 | # A_5 = PHI (A_4, A_2); | |
161 | ||
162 | # VUSE <A_5> | |
163 | A.0_6 = A; | |
164 | ||
165 | return A.0_6; | |
166 | } | |
167 | ||
168 | The value of A_2 cannot be assumed to be UNDEFINED, as it may have | |
169 | been defined outside of foo. If we were to assume it UNDEFINED, we | |
bfa30570 | 170 | would erroneously optimize the above into 'return 3;'. |
88dbf20f | 171 | |
172 | Though STORE-CCP is not too expensive, it does have to do more work | |
173 | than regular CCP, so it is only enabled at -O2. Both regular CCP | |
174 | and STORE-CCP use the exact same algorithm. The only distinction | |
175 | is that when doing STORE-CCP, the boolean variable DO_STORE_CCP is | |
176 | set to true. This affects the evaluation of statements and PHI | |
177 | nodes. | |
4ee9c684 | 178 | |
179 | References: | |
180 | ||
181 | Constant propagation with conditional branches, | |
182 | Wegman and Zadeck, ACM TOPLAS 13(2):181-210. | |
183 | ||
184 | Building an Optimizing Compiler, | |
185 | Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9. | |
186 | ||
187 | Advanced Compiler Design and Implementation, | |
188 | Steven Muchnick, Morgan Kaufmann, 1997, Section 12.6 */ | |
189 | ||
190 | #include "config.h" | |
191 | #include "system.h" | |
192 | #include "coretypes.h" | |
193 | #include "tm.h" | |
4ee9c684 | 194 | #include "tree.h" |
41511585 | 195 | #include "flags.h" |
4ee9c684 | 196 | #include "rtl.h" |
197 | #include "tm_p.h" | |
41511585 | 198 | #include "ggc.h" |
4ee9c684 | 199 | #include "basic-block.h" |
41511585 | 200 | #include "output.h" |
41511585 | 201 | #include "expr.h" |
202 | #include "function.h" | |
4ee9c684 | 203 | #include "diagnostic.h" |
41511585 | 204 | #include "timevar.h" |
4ee9c684 | 205 | #include "tree-dump.h" |
41511585 | 206 | #include "tree-flow.h" |
4ee9c684 | 207 | #include "tree-pass.h" |
41511585 | 208 | #include "tree-ssa-propagate.h" |
209 | #include "langhooks.h" | |
8782adcf | 210 | #include "target.h" |
4ee9c684 | 211 | |
212 | ||
213 | /* Possible lattice values. */ | |
214 | typedef enum | |
215 | { | |
bfa30570 | 216 | UNINITIALIZED, |
4ee9c684 | 217 | UNDEFINED, |
218 | CONSTANT, | |
219 | VARYING | |
88dbf20f | 220 | } ccp_lattice_t; |
4ee9c684 | 221 | |
88dbf20f | 222 | /* Array of propagated constant values. After propagation, |
223 | CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If | |
224 | the constant is held in an SSA name representing a memory store | |
225 | (i.e., a V_MAY_DEF or V_MUST_DEF), CONST_VAL[I].MEM_REF will | |
226 | contain the actual memory reference used to store (i.e., the LHS of | |
227 | the assignment doing the store). */ | |
20140406 | 228 | static prop_value_t *const_val; |
4ee9c684 | 229 | |
88dbf20f | 230 | /* True if we are also propagating constants in stores and loads. */ |
231 | static bool do_store_ccp; | |
4ee9c684 | 232 | |
88dbf20f | 233 | /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */ |
01406fc0 | 234 | |
235 | static void | |
88dbf20f | 236 | dump_lattice_value (FILE *outf, const char *prefix, prop_value_t val) |
01406fc0 | 237 | { |
41511585 | 238 | switch (val.lattice_val) |
01406fc0 | 239 | { |
88dbf20f | 240 | case UNINITIALIZED: |
241 | fprintf (outf, "%sUNINITIALIZED", prefix); | |
242 | break; | |
41511585 | 243 | case UNDEFINED: |
244 | fprintf (outf, "%sUNDEFINED", prefix); | |
245 | break; | |
246 | case VARYING: | |
247 | fprintf (outf, "%sVARYING", prefix); | |
248 | break; | |
41511585 | 249 | case CONSTANT: |
250 | fprintf (outf, "%sCONSTANT ", prefix); | |
88dbf20f | 251 | print_generic_expr (outf, val.value, dump_flags); |
41511585 | 252 | break; |
253 | default: | |
8c0963c4 | 254 | gcc_unreachable (); |
41511585 | 255 | } |
01406fc0 | 256 | } |
4ee9c684 | 257 | |
4ee9c684 | 258 | |
88dbf20f | 259 | /* Print lattice value VAL to stderr. */ |
260 | ||
261 | void debug_lattice_value (prop_value_t val); | |
262 | ||
263 | void | |
264 | debug_lattice_value (prop_value_t val) | |
265 | { | |
266 | dump_lattice_value (stderr, "", val); | |
267 | fprintf (stderr, "\n"); | |
268 | } | |
4ee9c684 | 269 | |
4ee9c684 | 270 | |
d03bd588 | 271 | /* The regular is_gimple_min_invariant does a shallow test of the object. |
272 | It assumes that full gimplification has happened, or will happen on the | |
273 | object. For a value coming from DECL_INITIAL, this is not true, so we | |
191ec5a2 | 274 | have to be more strict ourselves. */ |
d03bd588 | 275 | |
276 | static bool | |
277 | ccp_decl_initial_min_invariant (tree t) | |
278 | { | |
279 | if (!is_gimple_min_invariant (t)) | |
280 | return false; | |
281 | if (TREE_CODE (t) == ADDR_EXPR) | |
282 | { | |
283 | /* Inline and unroll is_gimple_addressable. */ | |
284 | while (1) | |
285 | { | |
286 | t = TREE_OPERAND (t, 0); | |
287 | if (is_gimple_id (t)) | |
288 | return true; | |
289 | if (!handled_component_p (t)) | |
290 | return false; | |
291 | } | |
292 | } | |
293 | return true; | |
294 | } | |
295 | ||
296 | ||
88dbf20f | 297 | /* Compute a default value for variable VAR and store it in the |
298 | CONST_VAL array. The following rules are used to get default | |
299 | values: | |
01406fc0 | 300 | |
88dbf20f | 301 | 1- Global and static variables that are declared constant are |
302 | considered CONSTANT. | |
303 | ||
304 | 2- Any other value is considered UNDEFINED. This is useful when | |
41511585 | 305 | considering PHI nodes. PHI arguments that are undefined do not |
306 | change the constant value of the PHI node, which allows for more | |
88dbf20f | 307 | constants to be propagated. |
4ee9c684 | 308 | |
88dbf20f | 309 | 3- If SSA_NAME_VALUE is set and it is a constant, its value is |
310 | used. | |
4ee9c684 | 311 | |
88dbf20f | 312 | 4- Variables defined by statements other than assignments and PHI |
313 | nodes are considered VARYING. | |
4ee9c684 | 314 | |
bfa30570 | 315 | 5- Initial values of variables that are not GIMPLE registers are |
316 | considered VARYING. */ | |
4ee9c684 | 317 | |
88dbf20f | 318 | static prop_value_t |
319 | get_default_value (tree var) | |
320 | { | |
321 | tree sym = SSA_NAME_VAR (var); | |
322 | prop_value_t val = { UNINITIALIZED, NULL_TREE, NULL_TREE }; | |
bfa30570 | 323 | |
88dbf20f | 324 | if (!do_store_ccp && !is_gimple_reg (var)) |
4ee9c684 | 325 | { |
88dbf20f | 326 | /* Short circuit for regular CCP. We are not interested in any |
327 | non-register when DO_STORE_CCP is false. */ | |
41511585 | 328 | val.lattice_val = VARYING; |
4ee9c684 | 329 | } |
88dbf20f | 330 | else if (SSA_NAME_VALUE (var) |
331 | && is_gimple_min_invariant (SSA_NAME_VALUE (var))) | |
41511585 | 332 | { |
88dbf20f | 333 | val.lattice_val = CONSTANT; |
334 | val.value = SSA_NAME_VALUE (var); | |
41511585 | 335 | } |
88dbf20f | 336 | else if (TREE_STATIC (sym) |
337 | && TREE_READONLY (sym) | |
437f5d6b | 338 | && !MTAG_P (sym) |
88dbf20f | 339 | && DECL_INITIAL (sym) |
d03bd588 | 340 | && ccp_decl_initial_min_invariant (DECL_INITIAL (sym))) |
41511585 | 341 | { |
88dbf20f | 342 | /* Globals and static variables declared 'const' take their |
343 | initial value. */ | |
344 | val.lattice_val = CONSTANT; | |
345 | val.value = DECL_INITIAL (sym); | |
346 | val.mem_ref = sym; | |
41511585 | 347 | } |
348 | else | |
349 | { | |
41511585 | 350 | tree stmt = SSA_NAME_DEF_STMT (var); |
4ee9c684 | 351 | |
88dbf20f | 352 | if (IS_EMPTY_STMT (stmt)) |
353 | { | |
354 | /* Variables defined by an empty statement are those used | |
355 | before being initialized. If VAR is a local variable, we | |
bfa30570 | 356 | can assume initially that it is UNDEFINED, otherwise we must |
357 | consider it VARYING. */ | |
88dbf20f | 358 | if (is_gimple_reg (sym) && TREE_CODE (sym) != PARM_DECL) |
359 | val.lattice_val = UNDEFINED; | |
88dbf20f | 360 | else |
41511585 | 361 | val.lattice_val = VARYING; |
362 | } | |
88dbf20f | 363 | else if (TREE_CODE (stmt) == MODIFY_EXPR |
364 | || TREE_CODE (stmt) == PHI_NODE) | |
365 | { | |
366 | /* Any other variable defined by an assignment or a PHI node | |
bfa30570 | 367 | is considered UNDEFINED. */ |
368 | val.lattice_val = UNDEFINED; | |
88dbf20f | 369 | } |
370 | else | |
371 | { | |
372 | /* Otherwise, VAR will never take on a constant value. */ | |
373 | val.lattice_val = VARYING; | |
374 | } | |
41511585 | 375 | } |
4ee9c684 | 376 | |
41511585 | 377 | return val; |
378 | } | |
4ee9c684 | 379 | |
4ee9c684 | 380 | |
bfa30570 | 381 | /* Get the constant value associated with variable VAR. */ |
4ee9c684 | 382 | |
bfa30570 | 383 | static inline prop_value_t * |
384 | get_value (tree var) | |
88dbf20f | 385 | { |
386 | prop_value_t *val = &const_val[SSA_NAME_VERSION (var)]; | |
bfa30570 | 387 | |
388 | if (val->lattice_val == UNINITIALIZED) | |
4ee9c684 | 389 | *val = get_default_value (var); |
390 | ||
391 | return val; | |
392 | } | |
393 | ||
bfa30570 | 394 | /* Sets the value associated with VAR to VARYING. */ |
395 | ||
396 | static inline void | |
397 | set_value_varying (tree var) | |
398 | { | |
399 | prop_value_t *val = &const_val[SSA_NAME_VERSION (var)]; | |
400 | ||
401 | val->lattice_val = VARYING; | |
402 | val->value = NULL_TREE; | |
403 | val->mem_ref = NULL_TREE; | |
404 | } | |
4ee9c684 | 405 | |
88dbf20f | 406 | /* Set the value for variable VAR to NEW_VAL. Return true if the new |
407 | value is different from VAR's previous value. */ | |
4ee9c684 | 408 | |
41511585 | 409 | static bool |
88dbf20f | 410 | set_lattice_value (tree var, prop_value_t new_val) |
4ee9c684 | 411 | { |
bfa30570 | 412 | prop_value_t *old_val = get_value (var); |
88dbf20f | 413 | |
414 | /* Lattice transitions must always be monotonically increasing in | |
bfa30570 | 415 | value. If *OLD_VAL and NEW_VAL are the same, return false to |
416 | inform the caller that this was a non-transition. */ | |
417 | ||
88dbf20f | 418 | gcc_assert (old_val->lattice_val <= new_val.lattice_val |
419 | || (old_val->lattice_val == new_val.lattice_val | |
420 | && old_val->value == new_val.value | |
bfa30570 | 421 | && old_val->mem_ref == new_val.mem_ref)); |
88dbf20f | 422 | |
423 | if (old_val->lattice_val != new_val.lattice_val) | |
4ee9c684 | 424 | { |
41511585 | 425 | if (dump_file && (dump_flags & TDF_DETAILS)) |
426 | { | |
88dbf20f | 427 | dump_lattice_value (dump_file, "Lattice value changed to ", new_val); |
bfa30570 | 428 | fprintf (dump_file, ". Adding SSA edges to worklist.\n"); |
41511585 | 429 | } |
430 | ||
88dbf20f | 431 | *old_val = new_val; |
432 | ||
bfa30570 | 433 | gcc_assert (new_val.lattice_val != UNDEFINED); |
434 | return true; | |
4ee9c684 | 435 | } |
41511585 | 436 | |
437 | return false; | |
4ee9c684 | 438 | } |
439 | ||
440 | ||
88dbf20f | 441 | /* Return the likely CCP lattice value for STMT. |
4ee9c684 | 442 | |
41511585 | 443 | If STMT has no operands, then return CONSTANT. |
4ee9c684 | 444 | |
41511585 | 445 | Else if any operands of STMT are undefined, then return UNDEFINED. |
4ee9c684 | 446 | |
41511585 | 447 | Else if any operands of STMT are constants, then return CONSTANT. |
4ee9c684 | 448 | |
41511585 | 449 | Else return VARYING. */ |
4ee9c684 | 450 | |
88dbf20f | 451 | static ccp_lattice_t |
41511585 | 452 | likely_value (tree stmt) |
453 | { | |
bfa30570 | 454 | bool has_constant_operand; |
41511585 | 455 | stmt_ann_t ann; |
456 | tree use; | |
457 | ssa_op_iter iter; | |
4ee9c684 | 458 | |
41511585 | 459 | ann = stmt_ann (stmt); |
88dbf20f | 460 | |
461 | /* If the statement has volatile operands, it won't fold to a | |
462 | constant value. */ | |
463 | if (ann->has_volatile_ops) | |
464 | return VARYING; | |
465 | ||
466 | /* If we are not doing store-ccp, statements with loads | |
467 | and/or stores will never fold into a constant. */ | |
468 | if (!do_store_ccp | |
9d637cc5 | 469 | && !ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)) |
41511585 | 470 | return VARYING; |
4ee9c684 | 471 | |
88dbf20f | 472 | |
473 | /* A CALL_EXPR is assumed to be varying. NOTE: This may be overly | |
474 | conservative, in the presence of const and pure calls. */ | |
41511585 | 475 | if (get_call_expr_in (stmt) != NULL_TREE) |
476 | return VARYING; | |
4ee9c684 | 477 | |
88dbf20f | 478 | /* Anything other than assignments and conditional jumps are not |
479 | interesting for CCP. */ | |
480 | if (TREE_CODE (stmt) != MODIFY_EXPR | |
bfa30570 | 481 | && !(TREE_CODE (stmt) == RETURN_EXPR && get_rhs (stmt) != NULL_TREE) |
88dbf20f | 482 | && TREE_CODE (stmt) != COND_EXPR |
483 | && TREE_CODE (stmt) != SWITCH_EXPR) | |
484 | return VARYING; | |
485 | ||
b765fa12 | 486 | if (is_gimple_min_invariant (get_rhs (stmt))) |
487 | return CONSTANT; | |
488 | ||
bfa30570 | 489 | has_constant_operand = false; |
490 | FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE | SSA_OP_VUSE) | |
41511585 | 491 | { |
bfa30570 | 492 | prop_value_t *val = get_value (use); |
41511585 | 493 | |
bfa30570 | 494 | if (val->lattice_val == UNDEFINED) |
495 | return UNDEFINED; | |
88dbf20f | 496 | |
41511585 | 497 | if (val->lattice_val == CONSTANT) |
bfa30570 | 498 | has_constant_operand = true; |
4ee9c684 | 499 | } |
41511585 | 500 | |
bfa30570 | 501 | if (has_constant_operand |
502 | /* We do not consider virtual operands here -- load from read-only | |
503 | memory may have only VARYING virtual operands, but still be | |
504 | constant. */ | |
505 | || ZERO_SSA_OPERANDS (stmt, SSA_OP_USE)) | |
88dbf20f | 506 | return CONSTANT; |
507 | ||
bfa30570 | 508 | return VARYING; |
4ee9c684 | 509 | } |
510 | ||
bfa30570 | 511 | /* Returns true if STMT cannot be constant. */ |
512 | ||
513 | static bool | |
514 | surely_varying_stmt_p (tree stmt) | |
515 | { | |
516 | /* If the statement has operands that we cannot handle, it cannot be | |
517 | constant. */ | |
518 | if (stmt_ann (stmt)->has_volatile_ops) | |
519 | return true; | |
520 | ||
521 | if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)) | |
522 | { | |
523 | if (!do_store_ccp) | |
524 | return true; | |
525 | ||
526 | /* We can only handle simple loads and stores. */ | |
527 | if (!stmt_makes_single_load (stmt) | |
528 | && !stmt_makes_single_store (stmt)) | |
529 | return true; | |
530 | } | |
531 | ||
532 | /* If it contains a call, it is varying. */ | |
533 | if (get_call_expr_in (stmt) != NULL_TREE) | |
534 | return true; | |
535 | ||
536 | /* Anything other than assignments and conditional jumps are not | |
537 | interesting for CCP. */ | |
538 | if (TREE_CODE (stmt) != MODIFY_EXPR | |
539 | && !(TREE_CODE (stmt) == RETURN_EXPR && get_rhs (stmt) != NULL_TREE) | |
540 | && TREE_CODE (stmt) != COND_EXPR | |
541 | && TREE_CODE (stmt) != SWITCH_EXPR) | |
542 | return true; | |
543 | ||
544 | return false; | |
545 | } | |
4ee9c684 | 546 | |
41511585 | 547 | /* Initialize local data structures for CCP. */ |
4ee9c684 | 548 | |
549 | static void | |
41511585 | 550 | ccp_initialize (void) |
4ee9c684 | 551 | { |
41511585 | 552 | basic_block bb; |
4ee9c684 | 553 | |
680a19b9 | 554 | const_val = XNEWVEC (prop_value_t, num_ssa_names); |
88dbf20f | 555 | memset (const_val, 0, num_ssa_names * sizeof (*const_val)); |
4ee9c684 | 556 | |
41511585 | 557 | /* Initialize simulation flags for PHI nodes and statements. */ |
558 | FOR_EACH_BB (bb) | |
4ee9c684 | 559 | { |
41511585 | 560 | block_stmt_iterator i; |
4ee9c684 | 561 | |
41511585 | 562 | for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i)) |
563 | { | |
41511585 | 564 | tree stmt = bsi_stmt (i); |
bfa30570 | 565 | bool is_varying = surely_varying_stmt_p (stmt); |
4ee9c684 | 566 | |
bfa30570 | 567 | if (is_varying) |
41511585 | 568 | { |
88dbf20f | 569 | tree def; |
570 | ssa_op_iter iter; | |
571 | ||
572 | /* If the statement will not produce a constant, mark | |
573 | all its outputs VARYING. */ | |
574 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) | |
bfa30570 | 575 | { |
576 | if (is_varying) | |
577 | set_value_varying (def); | |
578 | } | |
41511585 | 579 | } |
580 | ||
41511585 | 581 | DONT_SIMULATE_AGAIN (stmt) = is_varying; |
582 | } | |
4ee9c684 | 583 | } |
584 | ||
bfa30570 | 585 | /* Now process PHI nodes. We never set DONT_SIMULATE_AGAIN on phi node, |
586 | since we do not know which edges are executable yet, except for | |
587 | phi nodes for virtual operands when we do not do store ccp. */ | |
41511585 | 588 | FOR_EACH_BB (bb) |
4ee9c684 | 589 | { |
88dbf20f | 590 | tree phi; |
41511585 | 591 | |
592 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) | |
593 | { | |
bfa30570 | 594 | if (!do_store_ccp && !is_gimple_reg (PHI_RESULT (phi))) |
595 | DONT_SIMULATE_AGAIN (phi) = true; | |
596 | else | |
597 | DONT_SIMULATE_AGAIN (phi) = false; | |
41511585 | 598 | } |
4ee9c684 | 599 | } |
41511585 | 600 | } |
4ee9c684 | 601 | |
4ee9c684 | 602 | |
88dbf20f | 603 | /* Do final substitution of propagated values, cleanup the flowgraph and |
604 | free allocated storage. */ | |
4ee9c684 | 605 | |
88dbf20f | 606 | static void |
607 | ccp_finalize (void) | |
4ee9c684 | 608 | { |
88dbf20f | 609 | /* Perform substitutions based on the known constant values. */ |
eea12c72 | 610 | substitute_and_fold (const_val, false); |
4ee9c684 | 611 | |
88dbf20f | 612 | free (const_val); |
4ee9c684 | 613 | } |
614 | ||
615 | ||
88dbf20f | 616 | /* Compute the meet operator between *VAL1 and *VAL2. Store the result |
617 | in VAL1. | |
618 | ||
619 | any M UNDEFINED = any | |
88dbf20f | 620 | any M VARYING = VARYING |
621 | Ci M Cj = Ci if (i == j) | |
622 | Ci M Cj = VARYING if (i != j) | |
bfa30570 | 623 | */ |
4ee9c684 | 624 | |
625 | static void | |
88dbf20f | 626 | ccp_lattice_meet (prop_value_t *val1, prop_value_t *val2) |
4ee9c684 | 627 | { |
88dbf20f | 628 | if (val1->lattice_val == UNDEFINED) |
4ee9c684 | 629 | { |
88dbf20f | 630 | /* UNDEFINED M any = any */ |
631 | *val1 = *val2; | |
41511585 | 632 | } |
88dbf20f | 633 | else if (val2->lattice_val == UNDEFINED) |
92481a4d | 634 | { |
88dbf20f | 635 | /* any M UNDEFINED = any |
636 | Nothing to do. VAL1 already contains the value we want. */ | |
637 | ; | |
92481a4d | 638 | } |
88dbf20f | 639 | else if (val1->lattice_val == VARYING |
640 | || val2->lattice_val == VARYING) | |
41511585 | 641 | { |
88dbf20f | 642 | /* any M VARYING = VARYING. */ |
643 | val1->lattice_val = VARYING; | |
644 | val1->value = NULL_TREE; | |
645 | val1->mem_ref = NULL_TREE; | |
41511585 | 646 | } |
88dbf20f | 647 | else if (val1->lattice_val == CONSTANT |
648 | && val2->lattice_val == CONSTANT | |
649 | && simple_cst_equal (val1->value, val2->value) == 1 | |
650 | && (!do_store_ccp | |
b765fa12 | 651 | || (val1->mem_ref && val2->mem_ref |
652 | && operand_equal_p (val1->mem_ref, val2->mem_ref, 0)))) | |
41511585 | 653 | { |
88dbf20f | 654 | /* Ci M Cj = Ci if (i == j) |
655 | Ci M Cj = VARYING if (i != j) | |
656 | ||
657 | If these two values come from memory stores, make sure that | |
658 | they come from the same memory reference. */ | |
659 | val1->lattice_val = CONSTANT; | |
660 | val1->value = val1->value; | |
661 | val1->mem_ref = val1->mem_ref; | |
41511585 | 662 | } |
663 | else | |
664 | { | |
88dbf20f | 665 | /* Any other combination is VARYING. */ |
666 | val1->lattice_val = VARYING; | |
667 | val1->value = NULL_TREE; | |
668 | val1->mem_ref = NULL_TREE; | |
41511585 | 669 | } |
4ee9c684 | 670 | } |
671 | ||
672 | ||
41511585 | 673 | /* Loop through the PHI_NODE's parameters for BLOCK and compare their |
674 | lattice values to determine PHI_NODE's lattice value. The value of a | |
88dbf20f | 675 | PHI node is determined calling ccp_lattice_meet with all the arguments |
41511585 | 676 | of the PHI node that are incoming via executable edges. */ |
4ee9c684 | 677 | |
41511585 | 678 | static enum ssa_prop_result |
679 | ccp_visit_phi_node (tree phi) | |
4ee9c684 | 680 | { |
41511585 | 681 | int i; |
88dbf20f | 682 | prop_value_t *old_val, new_val; |
4ee9c684 | 683 | |
41511585 | 684 | if (dump_file && (dump_flags & TDF_DETAILS)) |
4ee9c684 | 685 | { |
41511585 | 686 | fprintf (dump_file, "\nVisiting PHI node: "); |
687 | print_generic_expr (dump_file, phi, dump_flags); | |
4ee9c684 | 688 | } |
4ee9c684 | 689 | |
bfa30570 | 690 | old_val = get_value (PHI_RESULT (phi)); |
41511585 | 691 | switch (old_val->lattice_val) |
692 | { | |
693 | case VARYING: | |
88dbf20f | 694 | return SSA_PROP_VARYING; |
4ee9c684 | 695 | |
41511585 | 696 | case CONSTANT: |
697 | new_val = *old_val; | |
698 | break; | |
4ee9c684 | 699 | |
41511585 | 700 | case UNDEFINED: |
41511585 | 701 | new_val.lattice_val = UNDEFINED; |
88dbf20f | 702 | new_val.value = NULL_TREE; |
703 | new_val.mem_ref = NULL_TREE; | |
41511585 | 704 | break; |
4ee9c684 | 705 | |
41511585 | 706 | default: |
8c0963c4 | 707 | gcc_unreachable (); |
41511585 | 708 | } |
4ee9c684 | 709 | |
41511585 | 710 | for (i = 0; i < PHI_NUM_ARGS (phi); i++) |
711 | { | |
88dbf20f | 712 | /* Compute the meet operator over all the PHI arguments flowing |
713 | through executable edges. */ | |
41511585 | 714 | edge e = PHI_ARG_EDGE (phi, i); |
4ee9c684 | 715 | |
41511585 | 716 | if (dump_file && (dump_flags & TDF_DETAILS)) |
717 | { | |
718 | fprintf (dump_file, | |
719 | "\n Argument #%d (%d -> %d %sexecutable)\n", | |
720 | i, e->src->index, e->dest->index, | |
721 | (e->flags & EDGE_EXECUTABLE) ? "" : "not "); | |
722 | } | |
723 | ||
724 | /* If the incoming edge is executable, Compute the meet operator for | |
725 | the existing value of the PHI node and the current PHI argument. */ | |
726 | if (e->flags & EDGE_EXECUTABLE) | |
727 | { | |
88dbf20f | 728 | tree arg = PHI_ARG_DEF (phi, i); |
729 | prop_value_t arg_val; | |
4ee9c684 | 730 | |
88dbf20f | 731 | if (is_gimple_min_invariant (arg)) |
41511585 | 732 | { |
88dbf20f | 733 | arg_val.lattice_val = CONSTANT; |
734 | arg_val.value = arg; | |
735 | arg_val.mem_ref = NULL_TREE; | |
41511585 | 736 | } |
737 | else | |
bfa30570 | 738 | arg_val = *(get_value (arg)); |
4ee9c684 | 739 | |
88dbf20f | 740 | ccp_lattice_meet (&new_val, &arg_val); |
4ee9c684 | 741 | |
41511585 | 742 | if (dump_file && (dump_flags & TDF_DETAILS)) |
743 | { | |
744 | fprintf (dump_file, "\t"); | |
88dbf20f | 745 | print_generic_expr (dump_file, arg, dump_flags); |
746 | dump_lattice_value (dump_file, "\tValue: ", arg_val); | |
41511585 | 747 | fprintf (dump_file, "\n"); |
748 | } | |
4ee9c684 | 749 | |
41511585 | 750 | if (new_val.lattice_val == VARYING) |
751 | break; | |
752 | } | |
753 | } | |
4ee9c684 | 754 | |
755 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
41511585 | 756 | { |
757 | dump_lattice_value (dump_file, "\n PHI node value: ", new_val); | |
758 | fprintf (dump_file, "\n\n"); | |
759 | } | |
760 | ||
bfa30570 | 761 | /* Make the transition to the new value. */ |
41511585 | 762 | if (set_lattice_value (PHI_RESULT (phi), new_val)) |
763 | { | |
764 | if (new_val.lattice_val == VARYING) | |
765 | return SSA_PROP_VARYING; | |
766 | else | |
767 | return SSA_PROP_INTERESTING; | |
768 | } | |
769 | else | |
770 | return SSA_PROP_NOT_INTERESTING; | |
4ee9c684 | 771 | } |
772 | ||
773 | ||
41511585 | 774 | /* CCP specific front-end to the non-destructive constant folding |
775 | routines. | |
4ee9c684 | 776 | |
777 | Attempt to simplify the RHS of STMT knowing that one or more | |
778 | operands are constants. | |
779 | ||
780 | If simplification is possible, return the simplified RHS, | |
781 | otherwise return the original RHS. */ | |
782 | ||
783 | static tree | |
784 | ccp_fold (tree stmt) | |
785 | { | |
786 | tree rhs = get_rhs (stmt); | |
787 | enum tree_code code = TREE_CODE (rhs); | |
ce45a448 | 788 | enum tree_code_class kind = TREE_CODE_CLASS (code); |
4ee9c684 | 789 | tree retval = NULL_TREE; |
790 | ||
4ee9c684 | 791 | if (TREE_CODE (rhs) == SSA_NAME) |
88dbf20f | 792 | { |
793 | /* If the RHS is an SSA_NAME, return its known constant value, | |
794 | if any. */ | |
bfa30570 | 795 | return get_value (rhs)->value; |
88dbf20f | 796 | } |
797 | else if (do_store_ccp && stmt_makes_single_load (stmt)) | |
798 | { | |
799 | /* If the RHS is a memory load, see if the VUSEs associated with | |
800 | it are a valid constant for that memory load. */ | |
801 | prop_value_t *val = get_value_loaded_by (stmt, const_val); | |
5d66655a | 802 | if (val && val->mem_ref) |
803 | { | |
804 | if (operand_equal_p (val->mem_ref, rhs, 0)) | |
805 | return val->value; | |
806 | ||
807 | /* If RHS is extracting REALPART_EXPR or IMAGPART_EXPR of a | |
808 | complex type with a known constant value, return it. */ | |
809 | if ((TREE_CODE (rhs) == REALPART_EXPR | |
810 | || TREE_CODE (rhs) == IMAGPART_EXPR) | |
811 | && operand_equal_p (val->mem_ref, TREE_OPERAND (rhs, 0), 0)) | |
812 | return fold_build1 (TREE_CODE (rhs), TREE_TYPE (rhs), val->value); | |
813 | } | |
814 | return NULL_TREE; | |
88dbf20f | 815 | } |
4ee9c684 | 816 | |
817 | /* Unary operators. Note that we know the single operand must | |
818 | be a constant. So this should almost always return a | |
819 | simplified RHS. */ | |
ce45a448 | 820 | if (kind == tcc_unary) |
4ee9c684 | 821 | { |
822 | /* Handle unary operators which can appear in GIMPLE form. */ | |
823 | tree op0 = TREE_OPERAND (rhs, 0); | |
824 | ||
825 | /* Simplify the operand down to a constant. */ | |
826 | if (TREE_CODE (op0) == SSA_NAME) | |
827 | { | |
bfa30570 | 828 | prop_value_t *val = get_value (op0); |
4ee9c684 | 829 | if (val->lattice_val == CONSTANT) |
bfa30570 | 830 | op0 = get_value (op0)->value; |
4ee9c684 | 831 | } |
832 | ||
ad78532f | 833 | if ((code == NOP_EXPR || code == CONVERT_EXPR) |
834 | && tree_ssa_useless_type_conversion_1 (TREE_TYPE (rhs), | |
835 | TREE_TYPE (op0))) | |
836 | return op0; | |
1675c594 | 837 | return fold_unary (code, TREE_TYPE (rhs), op0); |
4ee9c684 | 838 | } |
839 | ||
840 | /* Binary and comparison operators. We know one or both of the | |
841 | operands are constants. */ | |
ce45a448 | 842 | else if (kind == tcc_binary |
843 | || kind == tcc_comparison | |
4ee9c684 | 844 | || code == TRUTH_AND_EXPR |
845 | || code == TRUTH_OR_EXPR | |
846 | || code == TRUTH_XOR_EXPR) | |
847 | { | |
848 | /* Handle binary and comparison operators that can appear in | |
849 | GIMPLE form. */ | |
850 | tree op0 = TREE_OPERAND (rhs, 0); | |
851 | tree op1 = TREE_OPERAND (rhs, 1); | |
852 | ||
853 | /* Simplify the operands down to constants when appropriate. */ | |
854 | if (TREE_CODE (op0) == SSA_NAME) | |
855 | { | |
bfa30570 | 856 | prop_value_t *val = get_value (op0); |
4ee9c684 | 857 | if (val->lattice_val == CONSTANT) |
88dbf20f | 858 | op0 = val->value; |
4ee9c684 | 859 | } |
860 | ||
861 | if (TREE_CODE (op1) == SSA_NAME) | |
862 | { | |
bfa30570 | 863 | prop_value_t *val = get_value (op1); |
4ee9c684 | 864 | if (val->lattice_val == CONSTANT) |
88dbf20f | 865 | op1 = val->value; |
4ee9c684 | 866 | } |
867 | ||
1675c594 | 868 | return fold_binary (code, TREE_TYPE (rhs), op0, op1); |
4ee9c684 | 869 | } |
870 | ||
871 | /* We may be able to fold away calls to builtin functions if their | |
0bed3869 | 872 | arguments are constants. */ |
4ee9c684 | 873 | else if (code == CALL_EXPR |
874 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == ADDR_EXPR | |
875 | && (TREE_CODE (TREE_OPERAND (TREE_OPERAND (rhs, 0), 0)) | |
876 | == FUNCTION_DECL) | |
877 | && DECL_BUILT_IN (TREE_OPERAND (TREE_OPERAND (rhs, 0), 0))) | |
878 | { | |
b66731e8 | 879 | if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_USE)) |
4ee9c684 | 880 | { |
b66731e8 | 881 | tree *orig, var; |
4a4d48d5 | 882 | tree fndecl, arglist; |
b66731e8 | 883 | size_t i = 0; |
884 | ssa_op_iter iter; | |
885 | use_operand_p var_p; | |
4ee9c684 | 886 | |
887 | /* Preserve the original values of every operand. */ | |
680a19b9 | 888 | orig = XNEWVEC (tree, NUM_SSA_OPERANDS (stmt, SSA_OP_USE)); |
b66731e8 | 889 | FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_USE) |
890 | orig[i++] = var; | |
4ee9c684 | 891 | |
892 | /* Substitute operands with their values and try to fold. */ | |
88dbf20f | 893 | replace_uses_in (stmt, NULL, const_val); |
4a4d48d5 | 894 | fndecl = get_callee_fndecl (rhs); |
895 | arglist = TREE_OPERAND (rhs, 1); | |
896 | retval = fold_builtin (fndecl, arglist, false); | |
4ee9c684 | 897 | |
898 | /* Restore operands to their original form. */ | |
b66731e8 | 899 | i = 0; |
900 | FOR_EACH_SSA_USE_OPERAND (var_p, stmt, iter, SSA_OP_USE) | |
901 | SET_USE (var_p, orig[i++]); | |
4ee9c684 | 902 | free (orig); |
903 | } | |
904 | } | |
905 | else | |
906 | return rhs; | |
907 | ||
908 | /* If we got a simplified form, see if we need to convert its type. */ | |
909 | if (retval) | |
f0613857 | 910 | return fold_convert (TREE_TYPE (rhs), retval); |
4ee9c684 | 911 | |
912 | /* No simplification was possible. */ | |
913 | return rhs; | |
914 | } | |
915 | ||
916 | ||
8782adcf | 917 | /* Return the tree representing the element referenced by T if T is an |
918 | ARRAY_REF or COMPONENT_REF into constant aggregates. Return | |
919 | NULL_TREE otherwise. */ | |
920 | ||
921 | static tree | |
922 | fold_const_aggregate_ref (tree t) | |
923 | { | |
924 | prop_value_t *value; | |
c75b4594 | 925 | tree base, ctor, idx, field; |
926 | unsigned HOST_WIDE_INT cnt; | |
927 | tree cfield, cval; | |
8782adcf | 928 | |
929 | switch (TREE_CODE (t)) | |
930 | { | |
931 | case ARRAY_REF: | |
932 | /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its | |
933 | DECL_INITIAL. If BASE is a nested reference into another | |
934 | ARRAY_REF or COMPONENT_REF, make a recursive call to resolve | |
935 | the inner reference. */ | |
936 | base = TREE_OPERAND (t, 0); | |
937 | switch (TREE_CODE (base)) | |
938 | { | |
939 | case VAR_DECL: | |
940 | if (!TREE_READONLY (base) | |
941 | || TREE_CODE (TREE_TYPE (base)) != ARRAY_TYPE | |
942 | || !targetm.binds_local_p (base)) | |
943 | return NULL_TREE; | |
944 | ||
945 | ctor = DECL_INITIAL (base); | |
946 | break; | |
947 | ||
948 | case ARRAY_REF: | |
949 | case COMPONENT_REF: | |
950 | ctor = fold_const_aggregate_ref (base); | |
951 | break; | |
952 | ||
953 | default: | |
954 | return NULL_TREE; | |
955 | } | |
956 | ||
957 | if (ctor == NULL_TREE | |
4f61cce6 | 958 | || (TREE_CODE (ctor) != CONSTRUCTOR |
959 | && TREE_CODE (ctor) != STRING_CST) | |
8782adcf | 960 | || !TREE_STATIC (ctor)) |
961 | return NULL_TREE; | |
962 | ||
963 | /* Get the index. If we have an SSA_NAME, try to resolve it | |
964 | with the current lattice value for the SSA_NAME. */ | |
965 | idx = TREE_OPERAND (t, 1); | |
966 | switch (TREE_CODE (idx)) | |
967 | { | |
968 | case SSA_NAME: | |
bfa30570 | 969 | if ((value = get_value (idx)) |
8782adcf | 970 | && value->lattice_val == CONSTANT |
971 | && TREE_CODE (value->value) == INTEGER_CST) | |
972 | idx = value->value; | |
973 | else | |
974 | return NULL_TREE; | |
975 | break; | |
976 | ||
977 | case INTEGER_CST: | |
978 | break; | |
979 | ||
980 | default: | |
981 | return NULL_TREE; | |
982 | } | |
983 | ||
4f61cce6 | 984 | /* Fold read from constant string. */ |
985 | if (TREE_CODE (ctor) == STRING_CST) | |
986 | { | |
987 | if ((TYPE_MODE (TREE_TYPE (t)) | |
988 | == TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
989 | && (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
990 | == MODE_INT) | |
991 | && GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) == 1 | |
992 | && compare_tree_int (idx, TREE_STRING_LENGTH (ctor)) < 0) | |
993 | return build_int_cst (TREE_TYPE (t), (TREE_STRING_POINTER (ctor) | |
994 | [TREE_INT_CST_LOW (idx)])); | |
995 | return NULL_TREE; | |
996 | } | |
997 | ||
8782adcf | 998 | /* Whoo-hoo! I'll fold ya baby. Yeah! */ |
c75b4594 | 999 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) |
1000 | if (tree_int_cst_equal (cfield, idx)) | |
1001 | return cval; | |
8782adcf | 1002 | break; |
1003 | ||
1004 | case COMPONENT_REF: | |
1005 | /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its | |
1006 | DECL_INITIAL. If BASE is a nested reference into another | |
1007 | ARRAY_REF or COMPONENT_REF, make a recursive call to resolve | |
1008 | the inner reference. */ | |
1009 | base = TREE_OPERAND (t, 0); | |
1010 | switch (TREE_CODE (base)) | |
1011 | { | |
1012 | case VAR_DECL: | |
1013 | if (!TREE_READONLY (base) | |
1014 | || TREE_CODE (TREE_TYPE (base)) != RECORD_TYPE | |
1015 | || !targetm.binds_local_p (base)) | |
1016 | return NULL_TREE; | |
1017 | ||
1018 | ctor = DECL_INITIAL (base); | |
1019 | break; | |
1020 | ||
1021 | case ARRAY_REF: | |
1022 | case COMPONENT_REF: | |
1023 | ctor = fold_const_aggregate_ref (base); | |
1024 | break; | |
1025 | ||
1026 | default: | |
1027 | return NULL_TREE; | |
1028 | } | |
1029 | ||
1030 | if (ctor == NULL_TREE | |
1031 | || TREE_CODE (ctor) != CONSTRUCTOR | |
1032 | || !TREE_STATIC (ctor)) | |
1033 | return NULL_TREE; | |
1034 | ||
1035 | field = TREE_OPERAND (t, 1); | |
1036 | ||
c75b4594 | 1037 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) |
1038 | if (cfield == field | |
8782adcf | 1039 | /* FIXME: Handle bit-fields. */ |
c75b4594 | 1040 | && ! DECL_BIT_FIELD (cfield)) |
1041 | return cval; | |
8782adcf | 1042 | break; |
1043 | ||
908cb59d | 1044 | case REALPART_EXPR: |
1045 | case IMAGPART_EXPR: | |
1046 | { | |
1047 | tree c = fold_const_aggregate_ref (TREE_OPERAND (t, 0)); | |
1048 | if (c && TREE_CODE (c) == COMPLEX_CST) | |
1049 | return fold_build1 (TREE_CODE (t), TREE_TYPE (t), c); | |
1050 | break; | |
1051 | } | |
1052 | ||
8782adcf | 1053 | default: |
1054 | break; | |
1055 | } | |
1056 | ||
1057 | return NULL_TREE; | |
1058 | } | |
1059 | ||
4ee9c684 | 1060 | /* Evaluate statement STMT. */ |
1061 | ||
88dbf20f | 1062 | static prop_value_t |
4ee9c684 | 1063 | evaluate_stmt (tree stmt) |
1064 | { | |
88dbf20f | 1065 | prop_value_t val; |
4f61cce6 | 1066 | tree simplified = NULL_TREE; |
88dbf20f | 1067 | ccp_lattice_t likelyvalue = likely_value (stmt); |
1068 | ||
1069 | val.mem_ref = NULL_TREE; | |
4ee9c684 | 1070 | |
1071 | /* If the statement is likely to have a CONSTANT result, then try | |
1072 | to fold the statement to determine the constant value. */ | |
1073 | if (likelyvalue == CONSTANT) | |
1074 | simplified = ccp_fold (stmt); | |
1075 | /* If the statement is likely to have a VARYING result, then do not | |
1076 | bother folding the statement. */ | |
4f61cce6 | 1077 | if (likelyvalue == VARYING) |
4ee9c684 | 1078 | simplified = get_rhs (stmt); |
8782adcf | 1079 | /* If the statement is an ARRAY_REF or COMPONENT_REF into constant |
1080 | aggregates, extract the referenced constant. Otherwise the | |
1081 | statement is likely to have an UNDEFINED value, and there will be | |
1082 | nothing to do. Note that fold_const_aggregate_ref returns | |
1083 | NULL_TREE if the first case does not match. */ | |
4f61cce6 | 1084 | else if (!simplified) |
8782adcf | 1085 | simplified = fold_const_aggregate_ref (get_rhs (stmt)); |
4ee9c684 | 1086 | |
1087 | if (simplified && is_gimple_min_invariant (simplified)) | |
1088 | { | |
1089 | /* The statement produced a constant value. */ | |
1090 | val.lattice_val = CONSTANT; | |
88dbf20f | 1091 | val.value = simplified; |
4ee9c684 | 1092 | } |
1093 | else | |
1094 | { | |
1095 | /* The statement produced a nonconstant value. If the statement | |
88dbf20f | 1096 | had UNDEFINED operands, then the result of the statement |
1097 | should be UNDEFINED. Otherwise, the statement is VARYING. */ | |
bfa30570 | 1098 | if (likelyvalue == UNDEFINED) |
b765fa12 | 1099 | val.lattice_val = likelyvalue; |
1100 | else | |
1101 | val.lattice_val = VARYING; | |
1102 | ||
88dbf20f | 1103 | val.value = NULL_TREE; |
4ee9c684 | 1104 | } |
41511585 | 1105 | |
1106 | return val; | |
4ee9c684 | 1107 | } |
1108 | ||
1109 | ||
41511585 | 1110 | /* Visit the assignment statement STMT. Set the value of its LHS to the |
88dbf20f | 1111 | value computed by the RHS and store LHS in *OUTPUT_P. If STMT |
1112 | creates virtual definitions, set the value of each new name to that | |
1113 | of the RHS (if we can derive a constant out of the RHS). */ | |
4ee9c684 | 1114 | |
41511585 | 1115 | static enum ssa_prop_result |
1116 | visit_assignment (tree stmt, tree *output_p) | |
4ee9c684 | 1117 | { |
88dbf20f | 1118 | prop_value_t val; |
41511585 | 1119 | tree lhs, rhs; |
88dbf20f | 1120 | enum ssa_prop_result retval; |
4ee9c684 | 1121 | |
41511585 | 1122 | lhs = TREE_OPERAND (stmt, 0); |
1123 | rhs = TREE_OPERAND (stmt, 1); | |
4ee9c684 | 1124 | |
41511585 | 1125 | if (TREE_CODE (rhs) == SSA_NAME) |
1126 | { | |
1127 | /* For a simple copy operation, we copy the lattice values. */ | |
bfa30570 | 1128 | prop_value_t *nval = get_value (rhs); |
41511585 | 1129 | val = *nval; |
1130 | } | |
88dbf20f | 1131 | else if (do_store_ccp && stmt_makes_single_load (stmt)) |
41511585 | 1132 | { |
88dbf20f | 1133 | /* Same as above, but the RHS is not a gimple register and yet |
bfa30570 | 1134 | has a known VUSE. If STMT is loading from the same memory |
88dbf20f | 1135 | location that created the SSA_NAMEs for the virtual operands, |
1136 | we can propagate the value on the RHS. */ | |
1137 | prop_value_t *nval = get_value_loaded_by (stmt, const_val); | |
1138 | ||
bfa30570 | 1139 | if (nval |
1140 | && nval->mem_ref | |
b765fa12 | 1141 | && operand_equal_p (nval->mem_ref, rhs, 0)) |
88dbf20f | 1142 | val = *nval; |
1143 | else | |
1144 | val = evaluate_stmt (stmt); | |
41511585 | 1145 | } |
1146 | else | |
a065a588 | 1147 | /* Evaluate the statement. */ |
41511585 | 1148 | val = evaluate_stmt (stmt); |
4ee9c684 | 1149 | |
a065a588 | 1150 | /* If the original LHS was a VIEW_CONVERT_EXPR, modify the constant |
eb716043 | 1151 | value to be a VIEW_CONVERT_EXPR of the old constant value. |
a065a588 | 1152 | |
1153 | ??? Also, if this was a definition of a bitfield, we need to widen | |
41511585 | 1154 | the constant value into the type of the destination variable. This |
1155 | should not be necessary if GCC represented bitfields properly. */ | |
1156 | { | |
a065a588 | 1157 | tree orig_lhs = TREE_OPERAND (stmt, 0); |
1158 | ||
1159 | if (TREE_CODE (orig_lhs) == VIEW_CONVERT_EXPR | |
1160 | && val.lattice_val == CONSTANT) | |
1161 | { | |
5f9acd88 | 1162 | tree w = fold_unary (VIEW_CONVERT_EXPR, |
1163 | TREE_TYPE (TREE_OPERAND (orig_lhs, 0)), | |
1164 | val.value); | |
eb716043 | 1165 | |
662f5fa5 | 1166 | orig_lhs = TREE_OPERAND (orig_lhs, 0); |
eb716043 | 1167 | if (w && is_gimple_min_invariant (w)) |
88dbf20f | 1168 | val.value = w; |
eb716043 | 1169 | else |
1170 | { | |
1171 | val.lattice_val = VARYING; | |
88dbf20f | 1172 | val.value = NULL; |
eb716043 | 1173 | } |
a065a588 | 1174 | } |
1175 | ||
41511585 | 1176 | if (val.lattice_val == CONSTANT |
a065a588 | 1177 | && TREE_CODE (orig_lhs) == COMPONENT_REF |
1178 | && DECL_BIT_FIELD (TREE_OPERAND (orig_lhs, 1))) | |
4ee9c684 | 1179 | { |
88dbf20f | 1180 | tree w = widen_bitfield (val.value, TREE_OPERAND (orig_lhs, 1), |
a065a588 | 1181 | orig_lhs); |
41511585 | 1182 | |
1183 | if (w && is_gimple_min_invariant (w)) | |
88dbf20f | 1184 | val.value = w; |
41511585 | 1185 | else |
4ee9c684 | 1186 | { |
41511585 | 1187 | val.lattice_val = VARYING; |
88dbf20f | 1188 | val.value = NULL_TREE; |
1189 | val.mem_ref = NULL_TREE; | |
4ee9c684 | 1190 | } |
4ee9c684 | 1191 | } |
41511585 | 1192 | } |
4ee9c684 | 1193 | |
88dbf20f | 1194 | retval = SSA_PROP_NOT_INTERESTING; |
4ee9c684 | 1195 | |
41511585 | 1196 | /* Set the lattice value of the statement's output. */ |
88dbf20f | 1197 | if (TREE_CODE (lhs) == SSA_NAME) |
4ee9c684 | 1198 | { |
88dbf20f | 1199 | /* If STMT is an assignment to an SSA_NAME, we only have one |
1200 | value to set. */ | |
1201 | if (set_lattice_value (lhs, val)) | |
1202 | { | |
1203 | *output_p = lhs; | |
1204 | if (val.lattice_val == VARYING) | |
1205 | retval = SSA_PROP_VARYING; | |
1206 | else | |
1207 | retval = SSA_PROP_INTERESTING; | |
1208 | } | |
4ee9c684 | 1209 | } |
88dbf20f | 1210 | else if (do_store_ccp && stmt_makes_single_store (stmt)) |
1211 | { | |
1212 | /* Otherwise, set the names in V_MAY_DEF/V_MUST_DEF operands | |
1213 | to the new constant value and mark the LHS as the memory | |
1214 | reference associated with VAL. */ | |
1215 | ssa_op_iter i; | |
1216 | tree vdef; | |
1217 | bool changed; | |
1218 | ||
88dbf20f | 1219 | /* Mark VAL as stored in the LHS of this assignment. */ |
bfa30570 | 1220 | if (val.lattice_val == CONSTANT) |
1221 | val.mem_ref = lhs; | |
88dbf20f | 1222 | |
1223 | /* Set the value of every VDEF to VAL. */ | |
1224 | changed = false; | |
1225 | FOR_EACH_SSA_TREE_OPERAND (vdef, stmt, i, SSA_OP_VIRTUAL_DEFS) | |
1226 | changed |= set_lattice_value (vdef, val); | |
1227 | ||
1228 | /* Note that for propagation purposes, we are only interested in | |
1229 | visiting statements that load the exact same memory reference | |
1230 | stored here. Those statements will have the exact same list | |
1231 | of virtual uses, so it is enough to set the output of this | |
1232 | statement to be its first virtual definition. */ | |
1233 | *output_p = first_vdef (stmt); | |
1234 | if (changed) | |
1235 | { | |
1236 | if (val.lattice_val == VARYING) | |
1237 | retval = SSA_PROP_VARYING; | |
1238 | else | |
1239 | retval = SSA_PROP_INTERESTING; | |
1240 | } | |
1241 | } | |
1242 | ||
1243 | return retval; | |
4ee9c684 | 1244 | } |
1245 | ||
4ee9c684 | 1246 | |
41511585 | 1247 | /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING |
1248 | if it can determine which edge will be taken. Otherwise, return | |
1249 | SSA_PROP_VARYING. */ | |
1250 | ||
1251 | static enum ssa_prop_result | |
1252 | visit_cond_stmt (tree stmt, edge *taken_edge_p) | |
4ee9c684 | 1253 | { |
88dbf20f | 1254 | prop_value_t val; |
41511585 | 1255 | basic_block block; |
1256 | ||
1257 | block = bb_for_stmt (stmt); | |
1258 | val = evaluate_stmt (stmt); | |
1259 | ||
1260 | /* Find which edge out of the conditional block will be taken and add it | |
1261 | to the worklist. If no single edge can be determined statically, | |
1262 | return SSA_PROP_VARYING to feed all the outgoing edges to the | |
1263 | propagation engine. */ | |
88dbf20f | 1264 | *taken_edge_p = val.value ? find_taken_edge (block, val.value) : 0; |
41511585 | 1265 | if (*taken_edge_p) |
1266 | return SSA_PROP_INTERESTING; | |
1267 | else | |
1268 | return SSA_PROP_VARYING; | |
4ee9c684 | 1269 | } |
1270 | ||
4ee9c684 | 1271 | |
41511585 | 1272 | /* Evaluate statement STMT. If the statement produces an output value and |
1273 | its evaluation changes the lattice value of its output, return | |
1274 | SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the | |
1275 | output value. | |
1276 | ||
1277 | If STMT is a conditional branch and we can determine its truth | |
1278 | value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying | |
1279 | value, return SSA_PROP_VARYING. */ | |
4ee9c684 | 1280 | |
41511585 | 1281 | static enum ssa_prop_result |
1282 | ccp_visit_stmt (tree stmt, edge *taken_edge_p, tree *output_p) | |
1283 | { | |
41511585 | 1284 | tree def; |
1285 | ssa_op_iter iter; | |
4ee9c684 | 1286 | |
41511585 | 1287 | if (dump_file && (dump_flags & TDF_DETAILS)) |
4ee9c684 | 1288 | { |
88dbf20f | 1289 | fprintf (dump_file, "\nVisiting statement:\n"); |
1290 | print_generic_stmt (dump_file, stmt, dump_flags); | |
41511585 | 1291 | fprintf (dump_file, "\n"); |
4ee9c684 | 1292 | } |
4ee9c684 | 1293 | |
88dbf20f | 1294 | if (TREE_CODE (stmt) == MODIFY_EXPR) |
4ee9c684 | 1295 | { |
41511585 | 1296 | /* If the statement is an assignment that produces a single |
1297 | output value, evaluate its RHS to see if the lattice value of | |
1298 | its output has changed. */ | |
1299 | return visit_assignment (stmt, output_p); | |
4ee9c684 | 1300 | } |
41511585 | 1301 | else if (TREE_CODE (stmt) == COND_EXPR || TREE_CODE (stmt) == SWITCH_EXPR) |
4ee9c684 | 1302 | { |
41511585 | 1303 | /* If STMT is a conditional branch, see if we can determine |
1304 | which branch will be taken. */ | |
1305 | return visit_cond_stmt (stmt, taken_edge_p); | |
4ee9c684 | 1306 | } |
4ee9c684 | 1307 | |
41511585 | 1308 | /* Any other kind of statement is not interesting for constant |
1309 | propagation and, therefore, not worth simulating. */ | |
41511585 | 1310 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1311 | fprintf (dump_file, "No interesting values produced. Marked VARYING.\n"); | |
4ee9c684 | 1312 | |
41511585 | 1313 | /* Definitions made by statements other than assignments to |
1314 | SSA_NAMEs represent unknown modifications to their outputs. | |
1315 | Mark them VARYING. */ | |
88dbf20f | 1316 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) |
1317 | { | |
1318 | prop_value_t v = { VARYING, NULL_TREE, NULL_TREE }; | |
1319 | set_lattice_value (def, v); | |
1320 | } | |
4ee9c684 | 1321 | |
41511585 | 1322 | return SSA_PROP_VARYING; |
1323 | } | |
4ee9c684 | 1324 | |
4ee9c684 | 1325 | |
88dbf20f | 1326 | /* Main entry point for SSA Conditional Constant Propagation. */ |
41511585 | 1327 | |
1328 | static void | |
88dbf20f | 1329 | execute_ssa_ccp (bool store_ccp) |
41511585 | 1330 | { |
88dbf20f | 1331 | do_store_ccp = store_ccp; |
41511585 | 1332 | ccp_initialize (); |
1333 | ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node); | |
1334 | ccp_finalize (); | |
4ee9c684 | 1335 | } |
1336 | ||
5664499b | 1337 | |
2a1990e9 | 1338 | static unsigned int |
88dbf20f | 1339 | do_ssa_ccp (void) |
1340 | { | |
1341 | execute_ssa_ccp (false); | |
2a1990e9 | 1342 | return 0; |
88dbf20f | 1343 | } |
1344 | ||
1345 | ||
5664499b | 1346 | static bool |
41511585 | 1347 | gate_ccp (void) |
5664499b | 1348 | { |
41511585 | 1349 | return flag_tree_ccp != 0; |
5664499b | 1350 | } |
1351 | ||
4ee9c684 | 1352 | |
41511585 | 1353 | struct tree_opt_pass pass_ccp = |
1354 | { | |
1355 | "ccp", /* name */ | |
1356 | gate_ccp, /* gate */ | |
88dbf20f | 1357 | do_ssa_ccp, /* execute */ |
41511585 | 1358 | NULL, /* sub */ |
1359 | NULL, /* next */ | |
1360 | 0, /* static_pass_number */ | |
1361 | TV_TREE_CCP, /* tv_id */ | |
1362 | PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */ | |
1363 | 0, /* properties_provided */ | |
eff665b7 | 1364 | PROP_smt_usage, /* properties_destroyed */ |
41511585 | 1365 | 0, /* todo_flags_start */ |
88dbf20f | 1366 | TODO_cleanup_cfg | TODO_dump_func | TODO_update_ssa |
41511585 | 1367 | | TODO_ggc_collect | TODO_verify_ssa |
eff665b7 | 1368 | | TODO_verify_stmts | TODO_update_smt_usage, /* todo_flags_finish */ |
0f9005dd | 1369 | 0 /* letter */ |
41511585 | 1370 | }; |
4ee9c684 | 1371 | |
4ee9c684 | 1372 | |
2a1990e9 | 1373 | static unsigned int |
88dbf20f | 1374 | do_ssa_store_ccp (void) |
1375 | { | |
1376 | /* If STORE-CCP is not enabled, we just run regular CCP. */ | |
1377 | execute_ssa_ccp (flag_tree_store_ccp != 0); | |
2a1990e9 | 1378 | return 0; |
88dbf20f | 1379 | } |
1380 | ||
1381 | static bool | |
1382 | gate_store_ccp (void) | |
1383 | { | |
1384 | /* STORE-CCP is enabled only with -ftree-store-ccp, but when | |
1385 | -fno-tree-store-ccp is specified, we should run regular CCP. | |
1386 | That's why the pass is enabled with either flag. */ | |
1387 | return flag_tree_store_ccp != 0 || flag_tree_ccp != 0; | |
1388 | } | |
1389 | ||
1390 | ||
1391 | struct tree_opt_pass pass_store_ccp = | |
1392 | { | |
1393 | "store_ccp", /* name */ | |
1394 | gate_store_ccp, /* gate */ | |
1395 | do_ssa_store_ccp, /* execute */ | |
1396 | NULL, /* sub */ | |
1397 | NULL, /* next */ | |
1398 | 0, /* static_pass_number */ | |
1399 | TV_TREE_STORE_CCP, /* tv_id */ | |
1400 | PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */ | |
1401 | 0, /* properties_provided */ | |
eff665b7 | 1402 | PROP_smt_usage, /* properties_destroyed */ |
88dbf20f | 1403 | 0, /* todo_flags_start */ |
1404 | TODO_dump_func | TODO_update_ssa | |
1405 | | TODO_ggc_collect | TODO_verify_ssa | |
1406 | | TODO_cleanup_cfg | |
eff665b7 | 1407 | | TODO_verify_stmts | TODO_update_smt_usage, /* todo_flags_finish */ |
88dbf20f | 1408 | 0 /* letter */ |
1409 | }; | |
1410 | ||
41511585 | 1411 | /* Given a constant value VAL for bitfield FIELD, and a destination |
1412 | variable VAR, return VAL appropriately widened to fit into VAR. If | |
1413 | FIELD is wider than HOST_WIDE_INT, NULL is returned. */ | |
4ee9c684 | 1414 | |
41511585 | 1415 | tree |
1416 | widen_bitfield (tree val, tree field, tree var) | |
4ee9c684 | 1417 | { |
41511585 | 1418 | unsigned HOST_WIDE_INT var_size, field_size; |
1419 | tree wide_val; | |
1420 | unsigned HOST_WIDE_INT mask; | |
1421 | unsigned int i; | |
4ee9c684 | 1422 | |
41511585 | 1423 | /* We can only do this if the size of the type and field and VAL are |
1424 | all constants representable in HOST_WIDE_INT. */ | |
1425 | if (!host_integerp (TYPE_SIZE (TREE_TYPE (var)), 1) | |
1426 | || !host_integerp (DECL_SIZE (field), 1) | |
1427 | || !host_integerp (val, 0)) | |
1428 | return NULL_TREE; | |
4ee9c684 | 1429 | |
41511585 | 1430 | var_size = tree_low_cst (TYPE_SIZE (TREE_TYPE (var)), 1); |
1431 | field_size = tree_low_cst (DECL_SIZE (field), 1); | |
4ee9c684 | 1432 | |
41511585 | 1433 | /* Give up if either the bitfield or the variable are too wide. */ |
1434 | if (field_size > HOST_BITS_PER_WIDE_INT || var_size > HOST_BITS_PER_WIDE_INT) | |
1435 | return NULL_TREE; | |
4ee9c684 | 1436 | |
8c0963c4 | 1437 | gcc_assert (var_size >= field_size); |
4ee9c684 | 1438 | |
41511585 | 1439 | /* If the sign bit of the value is not set or the field's type is unsigned, |
1440 | just mask off the high order bits of the value. */ | |
1441 | if (DECL_UNSIGNED (field) | |
1442 | || !(tree_low_cst (val, 0) & (((HOST_WIDE_INT)1) << (field_size - 1)))) | |
1443 | { | |
1444 | /* Zero extension. Build a mask with the lower 'field_size' bits | |
1445 | set and a BIT_AND_EXPR node to clear the high order bits of | |
1446 | the value. */ | |
1447 | for (i = 0, mask = 0; i < field_size; i++) | |
1448 | mask |= ((HOST_WIDE_INT) 1) << i; | |
4ee9c684 | 1449 | |
e7be49a3 | 1450 | wide_val = fold_build2 (BIT_AND_EXPR, TREE_TYPE (var), val, |
1451 | build_int_cst (TREE_TYPE (var), mask)); | |
4ee9c684 | 1452 | } |
41511585 | 1453 | else |
5664499b | 1454 | { |
41511585 | 1455 | /* Sign extension. Create a mask with the upper 'field_size' |
1456 | bits set and a BIT_IOR_EXPR to set the high order bits of the | |
1457 | value. */ | |
1458 | for (i = 0, mask = 0; i < (var_size - field_size); i++) | |
1459 | mask |= ((HOST_WIDE_INT) 1) << (var_size - i - 1); | |
1460 | ||
e7be49a3 | 1461 | wide_val = fold_build2 (BIT_IOR_EXPR, TREE_TYPE (var), val, |
1462 | build_int_cst (TREE_TYPE (var), mask)); | |
5664499b | 1463 | } |
4ee9c684 | 1464 | |
e7be49a3 | 1465 | return wide_val; |
4ee9c684 | 1466 | } |
1467 | ||
41511585 | 1468 | |
4ee9c684 | 1469 | /* A subroutine of fold_stmt_r. Attempts to fold *(A+O) to A[X]. |
1470 | BASE is an array type. OFFSET is a byte displacement. ORIG_TYPE | |
0bed3869 | 1471 | is the desired result type. */ |
4ee9c684 | 1472 | |
1473 | static tree | |
1474 | maybe_fold_offset_to_array_ref (tree base, tree offset, tree orig_type) | |
1475 | { | |
6374121b | 1476 | tree min_idx, idx, elt_offset = integer_zero_node; |
1477 | tree array_type, elt_type, elt_size; | |
1478 | ||
1479 | /* If BASE is an ARRAY_REF, we can pick up another offset (this time | |
1480 | measured in units of the size of elements type) from that ARRAY_REF). | |
1481 | We can't do anything if either is variable. | |
1482 | ||
1483 | The case we handle here is *(&A[N]+O). */ | |
1484 | if (TREE_CODE (base) == ARRAY_REF) | |
1485 | { | |
1486 | tree low_bound = array_ref_low_bound (base); | |
1487 | ||
1488 | elt_offset = TREE_OPERAND (base, 1); | |
1489 | if (TREE_CODE (low_bound) != INTEGER_CST | |
1490 | || TREE_CODE (elt_offset) != INTEGER_CST) | |
1491 | return NULL_TREE; | |
1492 | ||
1493 | elt_offset = int_const_binop (MINUS_EXPR, elt_offset, low_bound, 0); | |
1494 | base = TREE_OPERAND (base, 0); | |
1495 | } | |
4ee9c684 | 1496 | |
1497 | /* Ignore stupid user tricks of indexing non-array variables. */ | |
1498 | array_type = TREE_TYPE (base); | |
1499 | if (TREE_CODE (array_type) != ARRAY_TYPE) | |
1500 | return NULL_TREE; | |
1501 | elt_type = TREE_TYPE (array_type); | |
1502 | if (!lang_hooks.types_compatible_p (orig_type, elt_type)) | |
1503 | return NULL_TREE; | |
1504 | ||
6374121b | 1505 | /* If OFFSET and ELT_OFFSET are zero, we don't care about the size of the |
1506 | element type (so we can use the alignment if it's not constant). | |
1507 | Otherwise, compute the offset as an index by using a division. If the | |
1508 | division isn't exact, then don't do anything. */ | |
4ee9c684 | 1509 | elt_size = TYPE_SIZE_UNIT (elt_type); |
6374121b | 1510 | if (integer_zerop (offset)) |
1511 | { | |
1512 | if (TREE_CODE (elt_size) != INTEGER_CST) | |
1513 | elt_size = size_int (TYPE_ALIGN (elt_type)); | |
4ee9c684 | 1514 | |
6374121b | 1515 | idx = integer_zero_node; |
1516 | } | |
1517 | else | |
1518 | { | |
1519 | unsigned HOST_WIDE_INT lquo, lrem; | |
1520 | HOST_WIDE_INT hquo, hrem; | |
1521 | ||
1522 | if (TREE_CODE (elt_size) != INTEGER_CST | |
1523 | || div_and_round_double (TRUNC_DIV_EXPR, 1, | |
1524 | TREE_INT_CST_LOW (offset), | |
1525 | TREE_INT_CST_HIGH (offset), | |
1526 | TREE_INT_CST_LOW (elt_size), | |
1527 | TREE_INT_CST_HIGH (elt_size), | |
1528 | &lquo, &hquo, &lrem, &hrem) | |
1529 | || lrem || hrem) | |
1530 | return NULL_TREE; | |
4ee9c684 | 1531 | |
7016c612 | 1532 | idx = build_int_cst_wide (NULL_TREE, lquo, hquo); |
6374121b | 1533 | } |
1534 | ||
1535 | /* Assume the low bound is zero. If there is a domain type, get the | |
1536 | low bound, if any, convert the index into that type, and add the | |
1537 | low bound. */ | |
1538 | min_idx = integer_zero_node; | |
1539 | if (TYPE_DOMAIN (array_type)) | |
4ee9c684 | 1540 | { |
6374121b | 1541 | if (TYPE_MIN_VALUE (TYPE_DOMAIN (array_type))) |
1542 | min_idx = TYPE_MIN_VALUE (TYPE_DOMAIN (array_type)); | |
1543 | else | |
1544 | min_idx = fold_convert (TYPE_DOMAIN (array_type), min_idx); | |
1545 | ||
1546 | if (TREE_CODE (min_idx) != INTEGER_CST) | |
1547 | return NULL_TREE; | |
1548 | ||
1549 | idx = fold_convert (TYPE_DOMAIN (array_type), idx); | |
1550 | elt_offset = fold_convert (TYPE_DOMAIN (array_type), elt_offset); | |
4ee9c684 | 1551 | } |
1552 | ||
6374121b | 1553 | if (!integer_zerop (min_idx)) |
1554 | idx = int_const_binop (PLUS_EXPR, idx, min_idx, 0); | |
1555 | if (!integer_zerop (elt_offset)) | |
1556 | idx = int_const_binop (PLUS_EXPR, idx, elt_offset, 0); | |
1557 | ||
40b19772 | 1558 | return build4 (ARRAY_REF, orig_type, base, idx, min_idx, |
1559 | size_int (tree_low_cst (elt_size, 1) | |
1560 | / (TYPE_ALIGN_UNIT (elt_type)))); | |
4ee9c684 | 1561 | } |
1562 | ||
41511585 | 1563 | |
4ee9c684 | 1564 | /* A subroutine of fold_stmt_r. Attempts to fold *(S+O) to S.X. |
1565 | BASE is a record type. OFFSET is a byte displacement. ORIG_TYPE | |
1566 | is the desired result type. */ | |
1567 | /* ??? This doesn't handle class inheritance. */ | |
1568 | ||
1569 | static tree | |
1570 | maybe_fold_offset_to_component_ref (tree record_type, tree base, tree offset, | |
1571 | tree orig_type, bool base_is_ptr) | |
1572 | { | |
6d5d8428 | 1573 | tree f, t, field_type, tail_array_field, field_offset; |
4ee9c684 | 1574 | |
1575 | if (TREE_CODE (record_type) != RECORD_TYPE | |
1576 | && TREE_CODE (record_type) != UNION_TYPE | |
1577 | && TREE_CODE (record_type) != QUAL_UNION_TYPE) | |
1578 | return NULL_TREE; | |
1579 | ||
1580 | /* Short-circuit silly cases. */ | |
1581 | if (lang_hooks.types_compatible_p (record_type, orig_type)) | |
1582 | return NULL_TREE; | |
1583 | ||
1584 | tail_array_field = NULL_TREE; | |
1585 | for (f = TYPE_FIELDS (record_type); f ; f = TREE_CHAIN (f)) | |
1586 | { | |
1587 | int cmp; | |
1588 | ||
1589 | if (TREE_CODE (f) != FIELD_DECL) | |
1590 | continue; | |
1591 | if (DECL_BIT_FIELD (f)) | |
1592 | continue; | |
6d5d8428 | 1593 | |
1594 | field_offset = byte_position (f); | |
1595 | if (TREE_CODE (field_offset) != INTEGER_CST) | |
4ee9c684 | 1596 | continue; |
1597 | ||
1598 | /* ??? Java creates "interesting" fields for representing base classes. | |
1599 | They have no name, and have no context. With no context, we get into | |
1600 | trouble with nonoverlapping_component_refs_p. Skip them. */ | |
1601 | if (!DECL_FIELD_CONTEXT (f)) | |
1602 | continue; | |
1603 | ||
1604 | /* The previous array field isn't at the end. */ | |
1605 | tail_array_field = NULL_TREE; | |
1606 | ||
1607 | /* Check to see if this offset overlaps with the field. */ | |
6d5d8428 | 1608 | cmp = tree_int_cst_compare (field_offset, offset); |
4ee9c684 | 1609 | if (cmp > 0) |
1610 | continue; | |
1611 | ||
1612 | field_type = TREE_TYPE (f); | |
4ee9c684 | 1613 | |
1614 | /* Here we exactly match the offset being checked. If the types match, | |
1615 | then we can return that field. */ | |
115073ff | 1616 | if (cmp == 0 |
1617 | && lang_hooks.types_compatible_p (orig_type, field_type)) | |
4ee9c684 | 1618 | { |
1619 | if (base_is_ptr) | |
1620 | base = build1 (INDIRECT_REF, record_type, base); | |
40b19772 | 1621 | t = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE); |
4ee9c684 | 1622 | return t; |
1623 | } | |
115073ff | 1624 | |
1625 | /* Don't care about offsets into the middle of scalars. */ | |
1626 | if (!AGGREGATE_TYPE_P (field_type)) | |
1627 | continue; | |
4ee9c684 | 1628 | |
115073ff | 1629 | /* Check for array at the end of the struct. This is often |
1630 | used as for flexible array members. We should be able to | |
1631 | turn this into an array access anyway. */ | |
1632 | if (TREE_CODE (field_type) == ARRAY_TYPE) | |
1633 | tail_array_field = f; | |
1634 | ||
1635 | /* Check the end of the field against the offset. */ | |
1636 | if (!DECL_SIZE_UNIT (f) | |
1637 | || TREE_CODE (DECL_SIZE_UNIT (f)) != INTEGER_CST) | |
1638 | continue; | |
1639 | t = int_const_binop (MINUS_EXPR, offset, field_offset, 1); | |
1640 | if (!tree_int_cst_lt (t, DECL_SIZE_UNIT (f))) | |
1641 | continue; | |
4ee9c684 | 1642 | |
115073ff | 1643 | /* If we matched, then set offset to the displacement into |
1644 | this field. */ | |
1645 | offset = t; | |
4ee9c684 | 1646 | goto found; |
1647 | } | |
1648 | ||
1649 | if (!tail_array_field) | |
1650 | return NULL_TREE; | |
1651 | ||
1652 | f = tail_array_field; | |
1653 | field_type = TREE_TYPE (f); | |
115073ff | 1654 | offset = int_const_binop (MINUS_EXPR, offset, byte_position (f), 1); |
4ee9c684 | 1655 | |
1656 | found: | |
1657 | /* If we get here, we've got an aggregate field, and a possibly | |
365db11e | 1658 | nonzero offset into them. Recurse and hope for a valid match. */ |
4ee9c684 | 1659 | if (base_is_ptr) |
1660 | base = build1 (INDIRECT_REF, record_type, base); | |
40b19772 | 1661 | base = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE); |
4ee9c684 | 1662 | |
1663 | t = maybe_fold_offset_to_array_ref (base, offset, orig_type); | |
1664 | if (t) | |
1665 | return t; | |
1666 | return maybe_fold_offset_to_component_ref (field_type, base, offset, | |
1667 | orig_type, false); | |
1668 | } | |
1669 | ||
41511585 | 1670 | |
4ee9c684 | 1671 | /* A subroutine of fold_stmt_r. Attempt to simplify *(BASE+OFFSET). |
1672 | Return the simplified expression, or NULL if nothing could be done. */ | |
1673 | ||
1674 | static tree | |
1675 | maybe_fold_stmt_indirect (tree expr, tree base, tree offset) | |
1676 | { | |
1677 | tree t; | |
1678 | ||
1679 | /* We may well have constructed a double-nested PLUS_EXPR via multiple | |
1680 | substitutions. Fold that down to one. Remove NON_LVALUE_EXPRs that | |
1681 | are sometimes added. */ | |
1682 | base = fold (base); | |
40bcfc86 | 1683 | STRIP_TYPE_NOPS (base); |
4ee9c684 | 1684 | TREE_OPERAND (expr, 0) = base; |
1685 | ||
1686 | /* One possibility is that the address reduces to a string constant. */ | |
1687 | t = fold_read_from_constant_string (expr); | |
1688 | if (t) | |
1689 | return t; | |
1690 | ||
1691 | /* Add in any offset from a PLUS_EXPR. */ | |
1692 | if (TREE_CODE (base) == PLUS_EXPR) | |
1693 | { | |
1694 | tree offset2; | |
1695 | ||
1696 | offset2 = TREE_OPERAND (base, 1); | |
1697 | if (TREE_CODE (offset2) != INTEGER_CST) | |
1698 | return NULL_TREE; | |
1699 | base = TREE_OPERAND (base, 0); | |
1700 | ||
1701 | offset = int_const_binop (PLUS_EXPR, offset, offset2, 1); | |
1702 | } | |
1703 | ||
1704 | if (TREE_CODE (base) == ADDR_EXPR) | |
1705 | { | |
1706 | /* Strip the ADDR_EXPR. */ | |
1707 | base = TREE_OPERAND (base, 0); | |
1708 | ||
e67e5e1f | 1709 | /* Fold away CONST_DECL to its value, if the type is scalar. */ |
1710 | if (TREE_CODE (base) == CONST_DECL | |
d03bd588 | 1711 | && ccp_decl_initial_min_invariant (DECL_INITIAL (base))) |
e67e5e1f | 1712 | return DECL_INITIAL (base); |
1713 | ||
4ee9c684 | 1714 | /* Try folding *(&B+O) to B[X]. */ |
1715 | t = maybe_fold_offset_to_array_ref (base, offset, TREE_TYPE (expr)); | |
1716 | if (t) | |
1717 | return t; | |
1718 | ||
1719 | /* Try folding *(&B+O) to B.X. */ | |
1720 | t = maybe_fold_offset_to_component_ref (TREE_TYPE (base), base, offset, | |
1721 | TREE_TYPE (expr), false); | |
1722 | if (t) | |
1723 | return t; | |
1724 | ||
6374121b | 1725 | /* Fold *&B to B. We can only do this if EXPR is the same type |
1726 | as BASE. We can't do this if EXPR is the element type of an array | |
1727 | and BASE is the array. */ | |
1728 | if (integer_zerop (offset) | |
1729 | && lang_hooks.types_compatible_p (TREE_TYPE (base), | |
1730 | TREE_TYPE (expr))) | |
4ee9c684 | 1731 | return base; |
1732 | } | |
1733 | else | |
1734 | { | |
1735 | /* We can get here for out-of-range string constant accesses, | |
1736 | such as "_"[3]. Bail out of the entire substitution search | |
1737 | and arrange for the entire statement to be replaced by a | |
06b27565 | 1738 | call to __builtin_trap. In all likelihood this will all be |
4ee9c684 | 1739 | constant-folded away, but in the meantime we can't leave with |
1740 | something that get_expr_operands can't understand. */ | |
1741 | ||
1742 | t = base; | |
1743 | STRIP_NOPS (t); | |
1744 | if (TREE_CODE (t) == ADDR_EXPR | |
1745 | && TREE_CODE (TREE_OPERAND (t, 0)) == STRING_CST) | |
1746 | { | |
1747 | /* FIXME: Except that this causes problems elsewhere with dead | |
1fa3a8f6 | 1748 | code not being deleted, and we die in the rtl expanders |
4ee9c684 | 1749 | because we failed to remove some ssa_name. In the meantime, |
1750 | just return zero. */ | |
1751 | /* FIXME2: This condition should be signaled by | |
1752 | fold_read_from_constant_string directly, rather than | |
1753 | re-checking for it here. */ | |
1754 | return integer_zero_node; | |
1755 | } | |
1756 | ||
1757 | /* Try folding *(B+O) to B->X. Still an improvement. */ | |
1758 | if (POINTER_TYPE_P (TREE_TYPE (base))) | |
1759 | { | |
1760 | t = maybe_fold_offset_to_component_ref (TREE_TYPE (TREE_TYPE (base)), | |
1761 | base, offset, | |
1762 | TREE_TYPE (expr), true); | |
1763 | if (t) | |
1764 | return t; | |
1765 | } | |
1766 | } | |
1767 | ||
1768 | /* Otherwise we had an offset that we could not simplify. */ | |
1769 | return NULL_TREE; | |
1770 | } | |
1771 | ||
41511585 | 1772 | |
4ee9c684 | 1773 | /* A subroutine of fold_stmt_r. EXPR is a PLUS_EXPR. |
1774 | ||
1775 | A quaint feature extant in our address arithmetic is that there | |
1776 | can be hidden type changes here. The type of the result need | |
1777 | not be the same as the type of the input pointer. | |
1778 | ||
1779 | What we're after here is an expression of the form | |
1780 | (T *)(&array + const) | |
1781 | where the cast doesn't actually exist, but is implicit in the | |
1782 | type of the PLUS_EXPR. We'd like to turn this into | |
1783 | &array[x] | |
1784 | which may be able to propagate further. */ | |
1785 | ||
1786 | static tree | |
1787 | maybe_fold_stmt_addition (tree expr) | |
1788 | { | |
1789 | tree op0 = TREE_OPERAND (expr, 0); | |
1790 | tree op1 = TREE_OPERAND (expr, 1); | |
1791 | tree ptr_type = TREE_TYPE (expr); | |
1792 | tree ptd_type; | |
1793 | tree t; | |
1794 | bool subtract = (TREE_CODE (expr) == MINUS_EXPR); | |
1795 | ||
1796 | /* We're only interested in pointer arithmetic. */ | |
1797 | if (!POINTER_TYPE_P (ptr_type)) | |
1798 | return NULL_TREE; | |
1799 | /* Canonicalize the integral operand to op1. */ | |
1800 | if (INTEGRAL_TYPE_P (TREE_TYPE (op0))) | |
1801 | { | |
1802 | if (subtract) | |
1803 | return NULL_TREE; | |
1804 | t = op0, op0 = op1, op1 = t; | |
1805 | } | |
1806 | /* It had better be a constant. */ | |
1807 | if (TREE_CODE (op1) != INTEGER_CST) | |
1808 | return NULL_TREE; | |
1809 | /* The first operand should be an ADDR_EXPR. */ | |
1810 | if (TREE_CODE (op0) != ADDR_EXPR) | |
1811 | return NULL_TREE; | |
1812 | op0 = TREE_OPERAND (op0, 0); | |
1813 | ||
1814 | /* If the first operand is an ARRAY_REF, expand it so that we can fold | |
1815 | the offset into it. */ | |
1816 | while (TREE_CODE (op0) == ARRAY_REF) | |
1817 | { | |
1818 | tree array_obj = TREE_OPERAND (op0, 0); | |
1819 | tree array_idx = TREE_OPERAND (op0, 1); | |
1820 | tree elt_type = TREE_TYPE (op0); | |
1821 | tree elt_size = TYPE_SIZE_UNIT (elt_type); | |
1822 | tree min_idx; | |
1823 | ||
1824 | if (TREE_CODE (array_idx) != INTEGER_CST) | |
1825 | break; | |
1826 | if (TREE_CODE (elt_size) != INTEGER_CST) | |
1827 | break; | |
1828 | ||
1829 | /* Un-bias the index by the min index of the array type. */ | |
1830 | min_idx = TYPE_DOMAIN (TREE_TYPE (array_obj)); | |
1831 | if (min_idx) | |
1832 | { | |
1833 | min_idx = TYPE_MIN_VALUE (min_idx); | |
1834 | if (min_idx) | |
1835 | { | |
6374121b | 1836 | if (TREE_CODE (min_idx) != INTEGER_CST) |
1837 | break; | |
1838 | ||
535664e3 | 1839 | array_idx = fold_convert (TREE_TYPE (min_idx), array_idx); |
4ee9c684 | 1840 | if (!integer_zerop (min_idx)) |
1841 | array_idx = int_const_binop (MINUS_EXPR, array_idx, | |
1842 | min_idx, 0); | |
1843 | } | |
1844 | } | |
1845 | ||
1846 | /* Convert the index to a byte offset. */ | |
535664e3 | 1847 | array_idx = fold_convert (sizetype, array_idx); |
4ee9c684 | 1848 | array_idx = int_const_binop (MULT_EXPR, array_idx, elt_size, 0); |
1849 | ||
1850 | /* Update the operands for the next round, or for folding. */ | |
1851 | /* If we're manipulating unsigned types, then folding into negative | |
1852 | values can produce incorrect results. Particularly if the type | |
1853 | is smaller than the width of the pointer. */ | |
1854 | if (subtract | |
1855 | && TYPE_UNSIGNED (TREE_TYPE (op1)) | |
1856 | && tree_int_cst_lt (array_idx, op1)) | |
1857 | return NULL; | |
1858 | op1 = int_const_binop (subtract ? MINUS_EXPR : PLUS_EXPR, | |
1859 | array_idx, op1, 0); | |
1860 | subtract = false; | |
1861 | op0 = array_obj; | |
1862 | } | |
1863 | ||
1864 | /* If we weren't able to fold the subtraction into another array reference, | |
1865 | canonicalize the integer for passing to the array and component ref | |
1866 | simplification functions. */ | |
1867 | if (subtract) | |
1868 | { | |
1869 | if (TYPE_UNSIGNED (TREE_TYPE (op1))) | |
1870 | return NULL; | |
5f9acd88 | 1871 | op1 = fold_unary (NEGATE_EXPR, TREE_TYPE (op1), op1); |
4ee9c684 | 1872 | /* ??? In theory fold should always produce another integer. */ |
5f9acd88 | 1873 | if (op1 == NULL || TREE_CODE (op1) != INTEGER_CST) |
4ee9c684 | 1874 | return NULL; |
1875 | } | |
1876 | ||
1877 | ptd_type = TREE_TYPE (ptr_type); | |
1878 | ||
1879 | /* At which point we can try some of the same things as for indirects. */ | |
1880 | t = maybe_fold_offset_to_array_ref (op0, op1, ptd_type); | |
1881 | if (!t) | |
1882 | t = maybe_fold_offset_to_component_ref (TREE_TYPE (op0), op0, op1, | |
1883 | ptd_type, false); | |
1884 | if (t) | |
1885 | t = build1 (ADDR_EXPR, ptr_type, t); | |
1886 | ||
1887 | return t; | |
1888 | } | |
1889 | ||
0d759d9c | 1890 | /* For passing state through walk_tree into fold_stmt_r and its |
1891 | children. */ | |
1892 | ||
1893 | struct fold_stmt_r_data | |
1894 | { | |
1895 | bool *changed_p; | |
1896 | bool *inside_addr_expr_p; | |
1897 | }; | |
1898 | ||
4ee9c684 | 1899 | /* Subroutine of fold_stmt called via walk_tree. We perform several |
1900 | simplifications of EXPR_P, mostly having to do with pointer arithmetic. */ | |
1901 | ||
1902 | static tree | |
1903 | fold_stmt_r (tree *expr_p, int *walk_subtrees, void *data) | |
1904 | { | |
680a19b9 | 1905 | struct fold_stmt_r_data *fold_stmt_r_data = (struct fold_stmt_r_data *) data; |
0d759d9c | 1906 | bool *inside_addr_expr_p = fold_stmt_r_data->inside_addr_expr_p; |
1907 | bool *changed_p = fold_stmt_r_data->changed_p; | |
4ee9c684 | 1908 | tree expr = *expr_p, t; |
1909 | ||
1910 | /* ??? It'd be nice if walk_tree had a pre-order option. */ | |
1911 | switch (TREE_CODE (expr)) | |
1912 | { | |
1913 | case INDIRECT_REF: | |
1914 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
1915 | if (t) | |
1916 | return t; | |
1917 | *walk_subtrees = 0; | |
1918 | ||
1919 | t = maybe_fold_stmt_indirect (expr, TREE_OPERAND (expr, 0), | |
1920 | integer_zero_node); | |
1921 | break; | |
1922 | ||
0d759d9c | 1923 | /* ??? Could handle more ARRAY_REFs here, as a variant of INDIRECT_REF. |
4ee9c684 | 1924 | We'd only want to bother decomposing an existing ARRAY_REF if |
1925 | the base array is found to have another offset contained within. | |
1926 | Otherwise we'd be wasting time. */ | |
0d759d9c | 1927 | case ARRAY_REF: |
1928 | /* If we are not processing expressions found within an | |
1929 | ADDR_EXPR, then we can fold constant array references. */ | |
1930 | if (!*inside_addr_expr_p) | |
1931 | t = fold_read_from_constant_string (expr); | |
1932 | else | |
1933 | t = NULL; | |
1934 | break; | |
4ee9c684 | 1935 | |
1936 | case ADDR_EXPR: | |
0d759d9c | 1937 | *inside_addr_expr_p = true; |
4ee9c684 | 1938 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); |
0d759d9c | 1939 | *inside_addr_expr_p = false; |
4ee9c684 | 1940 | if (t) |
1941 | return t; | |
1942 | *walk_subtrees = 0; | |
1943 | ||
1944 | /* Set TREE_INVARIANT properly so that the value is properly | |
1945 | considered constant, and so gets propagated as expected. */ | |
1946 | if (*changed_p) | |
750ad201 | 1947 | recompute_tree_invariant_for_addr_expr (expr); |
4ee9c684 | 1948 | return NULL_TREE; |
1949 | ||
1950 | case PLUS_EXPR: | |
1951 | case MINUS_EXPR: | |
1952 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
1953 | if (t) | |
1954 | return t; | |
1955 | t = walk_tree (&TREE_OPERAND (expr, 1), fold_stmt_r, data, NULL); | |
1956 | if (t) | |
1957 | return t; | |
1958 | *walk_subtrees = 0; | |
1959 | ||
1960 | t = maybe_fold_stmt_addition (expr); | |
1961 | break; | |
1962 | ||
1963 | case COMPONENT_REF: | |
1964 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
1965 | if (t) | |
1966 | return t; | |
1967 | *walk_subtrees = 0; | |
1968 | ||
504d3463 | 1969 | /* Make sure the FIELD_DECL is actually a field in the type on the lhs. |
1970 | We've already checked that the records are compatible, so we should | |
1971 | come up with a set of compatible fields. */ | |
1972 | { | |
1973 | tree expr_record = TREE_TYPE (TREE_OPERAND (expr, 0)); | |
1974 | tree expr_field = TREE_OPERAND (expr, 1); | |
1975 | ||
1976 | if (DECL_FIELD_CONTEXT (expr_field) != TYPE_MAIN_VARIANT (expr_record)) | |
1977 | { | |
1978 | expr_field = find_compatible_field (expr_record, expr_field); | |
1979 | TREE_OPERAND (expr, 1) = expr_field; | |
1980 | } | |
1981 | } | |
4ee9c684 | 1982 | break; |
1983 | ||
aed164c3 | 1984 | case TARGET_MEM_REF: |
1985 | t = maybe_fold_tmr (expr); | |
1986 | break; | |
1987 | ||
bb8a9715 | 1988 | case COND_EXPR: |
1989 | if (COMPARISON_CLASS_P (TREE_OPERAND (expr, 0))) | |
1990 | { | |
1991 | tree op0 = TREE_OPERAND (expr, 0); | |
1992 | tree tem = fold_binary (TREE_CODE (op0), TREE_TYPE (op0), | |
f2532264 | 1993 | TREE_OPERAND (op0, 0), |
1994 | TREE_OPERAND (op0, 1)); | |
1995 | if (tem && set_rhs (expr_p, tem)) | |
1996 | { | |
1997 | t = *expr_p; | |
1998 | break; | |
1999 | } | |
bb8a9715 | 2000 | } |
f2532264 | 2001 | return NULL_TREE; |
bb8a9715 | 2002 | |
4ee9c684 | 2003 | default: |
2004 | return NULL_TREE; | |
2005 | } | |
2006 | ||
2007 | if (t) | |
2008 | { | |
2009 | *expr_p = t; | |
2010 | *changed_p = true; | |
2011 | } | |
2012 | ||
2013 | return NULL_TREE; | |
2014 | } | |
2015 | ||
4ee9c684 | 2016 | |
0a39fd54 | 2017 | /* Return the string length, maximum string length or maximum value of |
2018 | ARG in LENGTH. | |
2019 | If ARG is an SSA name variable, follow its use-def chains. If LENGTH | |
2020 | is not NULL and, for TYPE == 0, its value is not equal to the length | |
2021 | we determine or if we are unable to determine the length or value, | |
2022 | return false. VISITED is a bitmap of visited variables. | |
2023 | TYPE is 0 if string length should be returned, 1 for maximum string | |
2024 | length and 2 for maximum value ARG can have. */ | |
4ee9c684 | 2025 | |
72648a0e | 2026 | static bool |
0a39fd54 | 2027 | get_maxval_strlen (tree arg, tree *length, bitmap visited, int type) |
4ee9c684 | 2028 | { |
41511585 | 2029 | tree var, def_stmt, val; |
2030 | ||
2031 | if (TREE_CODE (arg) != SSA_NAME) | |
72648a0e | 2032 | { |
0a39fd54 | 2033 | if (type == 2) |
2034 | { | |
2035 | val = arg; | |
2036 | if (TREE_CODE (val) != INTEGER_CST | |
2037 | || tree_int_cst_sgn (val) < 0) | |
2038 | return false; | |
2039 | } | |
2040 | else | |
2041 | val = c_strlen (arg, 1); | |
41511585 | 2042 | if (!val) |
72648a0e | 2043 | return false; |
e37235f0 | 2044 | |
0a39fd54 | 2045 | if (*length) |
2046 | { | |
2047 | if (type > 0) | |
2048 | { | |
2049 | if (TREE_CODE (*length) != INTEGER_CST | |
2050 | || TREE_CODE (val) != INTEGER_CST) | |
2051 | return false; | |
2052 | ||
2053 | if (tree_int_cst_lt (*length, val)) | |
2054 | *length = val; | |
2055 | return true; | |
2056 | } | |
2057 | else if (simple_cst_equal (val, *length) != 1) | |
2058 | return false; | |
2059 | } | |
4ee9c684 | 2060 | |
41511585 | 2061 | *length = val; |
2062 | return true; | |
4ee9c684 | 2063 | } |
72648a0e | 2064 | |
41511585 | 2065 | /* If we were already here, break the infinite cycle. */ |
2066 | if (bitmap_bit_p (visited, SSA_NAME_VERSION (arg))) | |
2067 | return true; | |
2068 | bitmap_set_bit (visited, SSA_NAME_VERSION (arg)); | |
2069 | ||
2070 | var = arg; | |
2071 | def_stmt = SSA_NAME_DEF_STMT (var); | |
4ee9c684 | 2072 | |
41511585 | 2073 | switch (TREE_CODE (def_stmt)) |
2074 | { | |
2075 | case MODIFY_EXPR: | |
2076 | { | |
0a39fd54 | 2077 | tree rhs; |
2078 | ||
41511585 | 2079 | /* The RHS of the statement defining VAR must either have a |
2080 | constant length or come from another SSA_NAME with a constant | |
2081 | length. */ | |
2082 | rhs = TREE_OPERAND (def_stmt, 1); | |
2083 | STRIP_NOPS (rhs); | |
0a39fd54 | 2084 | return get_maxval_strlen (rhs, length, visited, type); |
41511585 | 2085 | } |
4ee9c684 | 2086 | |
41511585 | 2087 | case PHI_NODE: |
2088 | { | |
2089 | /* All the arguments of the PHI node must have the same constant | |
2090 | length. */ | |
2091 | int i; | |
4ee9c684 | 2092 | |
41511585 | 2093 | for (i = 0; i < PHI_NUM_ARGS (def_stmt); i++) |
2094 | { | |
2095 | tree arg = PHI_ARG_DEF (def_stmt, i); | |
4ee9c684 | 2096 | |
41511585 | 2097 | /* If this PHI has itself as an argument, we cannot |
2098 | determine the string length of this argument. However, | |
2099 | if we can find a constant string length for the other | |
2100 | PHI args then we can still be sure that this is a | |
2101 | constant string length. So be optimistic and just | |
2102 | continue with the next argument. */ | |
2103 | if (arg == PHI_RESULT (def_stmt)) | |
2104 | continue; | |
4ee9c684 | 2105 | |
0a39fd54 | 2106 | if (!get_maxval_strlen (arg, length, visited, type)) |
41511585 | 2107 | return false; |
2108 | } | |
4ee9c684 | 2109 | |
41511585 | 2110 | return true; |
5664499b | 2111 | } |
4ee9c684 | 2112 | |
41511585 | 2113 | default: |
2114 | break; | |
4ee9c684 | 2115 | } |
2116 | ||
41511585 | 2117 | |
2118 | return false; | |
4ee9c684 | 2119 | } |
2120 | ||
2121 | ||
2122 | /* Fold builtin call FN in statement STMT. If it cannot be folded into a | |
2123 | constant, return NULL_TREE. Otherwise, return its constant value. */ | |
2124 | ||
2125 | static tree | |
2126 | ccp_fold_builtin (tree stmt, tree fn) | |
2127 | { | |
0a39fd54 | 2128 | tree result, val[3]; |
f0613857 | 2129 | tree callee, arglist, a; |
0a39fd54 | 2130 | int arg_mask, i, type; |
f0613857 | 2131 | bitmap visited; |
2132 | bool ignore; | |
4ee9c684 | 2133 | |
f0613857 | 2134 | ignore = TREE_CODE (stmt) != MODIFY_EXPR; |
4ee9c684 | 2135 | |
2136 | /* First try the generic builtin folder. If that succeeds, return the | |
2137 | result directly. */ | |
4a4d48d5 | 2138 | callee = get_callee_fndecl (fn); |
2139 | arglist = TREE_OPERAND (fn, 1); | |
2140 | result = fold_builtin (callee, arglist, ignore); | |
4ee9c684 | 2141 | if (result) |
0a39fd54 | 2142 | { |
2143 | if (ignore) | |
2144 | STRIP_NOPS (result); | |
2145 | return result; | |
2146 | } | |
f0613857 | 2147 | |
2148 | /* Ignore MD builtins. */ | |
f0613857 | 2149 | if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_MD) |
2150 | return NULL_TREE; | |
4ee9c684 | 2151 | |
2152 | /* If the builtin could not be folded, and it has no argument list, | |
2153 | we're done. */ | |
2154 | if (!arglist) | |
2155 | return NULL_TREE; | |
2156 | ||
2157 | /* Limit the work only for builtins we know how to simplify. */ | |
2158 | switch (DECL_FUNCTION_CODE (callee)) | |
2159 | { | |
2160 | case BUILT_IN_STRLEN: | |
2161 | case BUILT_IN_FPUTS: | |
2162 | case BUILT_IN_FPUTS_UNLOCKED: | |
0a39fd54 | 2163 | arg_mask = 1; |
2164 | type = 0; | |
4ee9c684 | 2165 | break; |
2166 | case BUILT_IN_STRCPY: | |
2167 | case BUILT_IN_STRNCPY: | |
0a39fd54 | 2168 | arg_mask = 2; |
2169 | type = 0; | |
2170 | break; | |
2171 | case BUILT_IN_MEMCPY_CHK: | |
2172 | case BUILT_IN_MEMPCPY_CHK: | |
2173 | case BUILT_IN_MEMMOVE_CHK: | |
2174 | case BUILT_IN_MEMSET_CHK: | |
2175 | case BUILT_IN_STRNCPY_CHK: | |
2176 | arg_mask = 4; | |
2177 | type = 2; | |
2178 | break; | |
2179 | case BUILT_IN_STRCPY_CHK: | |
2180 | case BUILT_IN_STPCPY_CHK: | |
2181 | arg_mask = 2; | |
2182 | type = 1; | |
2183 | break; | |
2184 | case BUILT_IN_SNPRINTF_CHK: | |
2185 | case BUILT_IN_VSNPRINTF_CHK: | |
2186 | arg_mask = 2; | |
2187 | type = 2; | |
4ee9c684 | 2188 | break; |
2189 | default: | |
2190 | return NULL_TREE; | |
2191 | } | |
2192 | ||
2193 | /* Try to use the dataflow information gathered by the CCP process. */ | |
27335ffd | 2194 | visited = BITMAP_ALLOC (NULL); |
4ee9c684 | 2195 | |
0a39fd54 | 2196 | memset (val, 0, sizeof (val)); |
4ee9c684 | 2197 | for (i = 0, a = arglist; |
0a39fd54 | 2198 | arg_mask; |
2199 | i++, arg_mask >>= 1, a = TREE_CHAIN (a)) | |
2200 | if (arg_mask & 1) | |
4ee9c684 | 2201 | { |
2202 | bitmap_clear (visited); | |
0a39fd54 | 2203 | if (!get_maxval_strlen (TREE_VALUE (a), &val[i], visited, type)) |
2204 | val[i] = NULL_TREE; | |
4ee9c684 | 2205 | } |
2206 | ||
27335ffd | 2207 | BITMAP_FREE (visited); |
4ee9c684 | 2208 | |
f0613857 | 2209 | result = NULL_TREE; |
4ee9c684 | 2210 | switch (DECL_FUNCTION_CODE (callee)) |
2211 | { | |
2212 | case BUILT_IN_STRLEN: | |
0a39fd54 | 2213 | if (val[0]) |
4ee9c684 | 2214 | { |
0a39fd54 | 2215 | tree new = fold_convert (TREE_TYPE (fn), val[0]); |
4ee9c684 | 2216 | |
2217 | /* If the result is not a valid gimple value, or not a cast | |
2218 | of a valid gimple value, then we can not use the result. */ | |
2219 | if (is_gimple_val (new) | |
2220 | || (is_gimple_cast (new) | |
2221 | && is_gimple_val (TREE_OPERAND (new, 0)))) | |
2222 | return new; | |
4ee9c684 | 2223 | } |
f0613857 | 2224 | break; |
2225 | ||
4ee9c684 | 2226 | case BUILT_IN_STRCPY: |
0a39fd54 | 2227 | if (val[1] && is_gimple_val (val[1])) |
2228 | result = fold_builtin_strcpy (callee, arglist, val[1]); | |
f0613857 | 2229 | break; |
2230 | ||
4ee9c684 | 2231 | case BUILT_IN_STRNCPY: |
0a39fd54 | 2232 | if (val[1] && is_gimple_val (val[1])) |
2233 | result = fold_builtin_strncpy (callee, arglist, val[1]); | |
f0613857 | 2234 | break; |
2235 | ||
4ee9c684 | 2236 | case BUILT_IN_FPUTS: |
f0613857 | 2237 | result = fold_builtin_fputs (arglist, |
2238 | TREE_CODE (stmt) != MODIFY_EXPR, 0, | |
0a39fd54 | 2239 | val[0]); |
f0613857 | 2240 | break; |
2241 | ||
4ee9c684 | 2242 | case BUILT_IN_FPUTS_UNLOCKED: |
f0613857 | 2243 | result = fold_builtin_fputs (arglist, |
2244 | TREE_CODE (stmt) != MODIFY_EXPR, 1, | |
0a39fd54 | 2245 | val[0]); |
2246 | break; | |
2247 | ||
2248 | case BUILT_IN_MEMCPY_CHK: | |
2249 | case BUILT_IN_MEMPCPY_CHK: | |
2250 | case BUILT_IN_MEMMOVE_CHK: | |
2251 | case BUILT_IN_MEMSET_CHK: | |
2252 | if (val[2] && is_gimple_val (val[2])) | |
2253 | result = fold_builtin_memory_chk (callee, arglist, val[2], ignore, | |
2254 | DECL_FUNCTION_CODE (callee)); | |
2255 | break; | |
2256 | ||
2257 | case BUILT_IN_STRCPY_CHK: | |
2258 | case BUILT_IN_STPCPY_CHK: | |
2259 | if (val[1] && is_gimple_val (val[1])) | |
2260 | result = fold_builtin_stxcpy_chk (callee, arglist, val[1], ignore, | |
2261 | DECL_FUNCTION_CODE (callee)); | |
2262 | break; | |
2263 | ||
2264 | case BUILT_IN_STRNCPY_CHK: | |
2265 | if (val[2] && is_gimple_val (val[2])) | |
2266 | result = fold_builtin_strncpy_chk (arglist, val[2]); | |
2267 | break; | |
2268 | ||
2269 | case BUILT_IN_SNPRINTF_CHK: | |
2270 | case BUILT_IN_VSNPRINTF_CHK: | |
2271 | if (val[1] && is_gimple_val (val[1])) | |
2272 | result = fold_builtin_snprintf_chk (arglist, val[1], | |
2273 | DECL_FUNCTION_CODE (callee)); | |
f0613857 | 2274 | break; |
4ee9c684 | 2275 | |
2276 | default: | |
8c0963c4 | 2277 | gcc_unreachable (); |
4ee9c684 | 2278 | } |
2279 | ||
f0613857 | 2280 | if (result && ignore) |
db97ad41 | 2281 | result = fold_ignored_result (result); |
f0613857 | 2282 | return result; |
4ee9c684 | 2283 | } |
2284 | ||
2285 | ||
5206b159 | 2286 | /* Fold the statement pointed to by STMT_P. In some cases, this function may |
41511585 | 2287 | replace the whole statement with a new one. Returns true iff folding |
2288 | makes any changes. */ | |
4ee9c684 | 2289 | |
41511585 | 2290 | bool |
2291 | fold_stmt (tree *stmt_p) | |
4ee9c684 | 2292 | { |
41511585 | 2293 | tree rhs, result, stmt; |
0d759d9c | 2294 | struct fold_stmt_r_data fold_stmt_r_data; |
41511585 | 2295 | bool changed = false; |
0d759d9c | 2296 | bool inside_addr_expr = false; |
2297 | ||
2298 | fold_stmt_r_data.changed_p = &changed; | |
2299 | fold_stmt_r_data.inside_addr_expr_p = &inside_addr_expr; | |
4ee9c684 | 2300 | |
41511585 | 2301 | stmt = *stmt_p; |
4ee9c684 | 2302 | |
41511585 | 2303 | /* If we replaced constants and the statement makes pointer dereferences, |
2304 | then we may need to fold instances of *&VAR into VAR, etc. */ | |
0d759d9c | 2305 | if (walk_tree (stmt_p, fold_stmt_r, &fold_stmt_r_data, NULL)) |
41511585 | 2306 | { |
2307 | *stmt_p | |
2308 | = build_function_call_expr (implicit_built_in_decls[BUILT_IN_TRAP], | |
2309 | NULL); | |
4ee9c684 | 2310 | return true; |
2311 | } | |
2312 | ||
41511585 | 2313 | rhs = get_rhs (stmt); |
2314 | if (!rhs) | |
2315 | return changed; | |
2316 | result = NULL_TREE; | |
4ee9c684 | 2317 | |
41511585 | 2318 | if (TREE_CODE (rhs) == CALL_EXPR) |
4ee9c684 | 2319 | { |
41511585 | 2320 | tree callee; |
4ee9c684 | 2321 | |
41511585 | 2322 | /* Check for builtins that CCP can handle using information not |
2323 | available in the generic fold routines. */ | |
2324 | callee = get_callee_fndecl (rhs); | |
2325 | if (callee && DECL_BUILT_IN (callee)) | |
2326 | result = ccp_fold_builtin (stmt, rhs); | |
e77b8618 | 2327 | else |
2328 | { | |
2329 | /* Check for resolvable OBJ_TYPE_REF. The only sorts we can resolve | |
2330 | here are when we've propagated the address of a decl into the | |
2331 | object slot. */ | |
2332 | /* ??? Should perhaps do this in fold proper. However, doing it | |
2333 | there requires that we create a new CALL_EXPR, and that requires | |
2334 | copying EH region info to the new node. Easier to just do it | |
2335 | here where we can just smash the call operand. Also | |
2336 | CALL_EXPR_RETURN_SLOT_OPT needs to be handled correctly and | |
2337 | copied, fold_ternary does not have not information. */ | |
2338 | callee = TREE_OPERAND (rhs, 0); | |
2339 | if (TREE_CODE (callee) == OBJ_TYPE_REF | |
2340 | && lang_hooks.fold_obj_type_ref | |
2341 | && TREE_CODE (OBJ_TYPE_REF_OBJECT (callee)) == ADDR_EXPR | |
2342 | && DECL_P (TREE_OPERAND | |
2343 | (OBJ_TYPE_REF_OBJECT (callee), 0))) | |
2344 | { | |
2345 | tree t; | |
2346 | ||
2347 | /* ??? Caution: Broken ADDR_EXPR semantics means that | |
2348 | looking at the type of the operand of the addr_expr | |
2349 | can yield an array type. See silly exception in | |
2350 | check_pointer_types_r. */ | |
2351 | ||
2352 | t = TREE_TYPE (TREE_TYPE (OBJ_TYPE_REF_OBJECT (callee))); | |
2353 | t = lang_hooks.fold_obj_type_ref (callee, t); | |
2354 | if (t) | |
2355 | { | |
2356 | TREE_OPERAND (rhs, 0) = t; | |
2357 | changed = true; | |
2358 | } | |
2359 | } | |
2360 | } | |
4ee9c684 | 2361 | } |
2362 | ||
41511585 | 2363 | /* If we couldn't fold the RHS, hand over to the generic fold routines. */ |
2364 | if (result == NULL_TREE) | |
2365 | result = fold (rhs); | |
4ee9c684 | 2366 | |
41511585 | 2367 | /* Strip away useless type conversions. Both the NON_LVALUE_EXPR that |
2368 | may have been added by fold, and "useless" type conversions that might | |
2369 | now be apparent due to propagation. */ | |
2370 | STRIP_USELESS_TYPE_CONVERSION (result); | |
2371 | ||
2372 | if (result != rhs) | |
2373 | changed |= set_rhs (stmt_p, result); | |
2374 | ||
2375 | return changed; | |
4ee9c684 | 2376 | } |
2377 | ||
8171a1dd | 2378 | /* Perform the minimal folding on statement STMT. Only operations like |
2379 | *&x created by constant propagation are handled. The statement cannot | |
2380 | be replaced with a new one. */ | |
2381 | ||
2382 | bool | |
2383 | fold_stmt_inplace (tree stmt) | |
2384 | { | |
2385 | tree old_stmt = stmt, rhs, new_rhs; | |
0d759d9c | 2386 | struct fold_stmt_r_data fold_stmt_r_data; |
8171a1dd | 2387 | bool changed = false; |
0d759d9c | 2388 | bool inside_addr_expr = false; |
2389 | ||
2390 | fold_stmt_r_data.changed_p = &changed; | |
2391 | fold_stmt_r_data.inside_addr_expr_p = &inside_addr_expr; | |
8171a1dd | 2392 | |
0d759d9c | 2393 | walk_tree (&stmt, fold_stmt_r, &fold_stmt_r_data, NULL); |
8171a1dd | 2394 | gcc_assert (stmt == old_stmt); |
2395 | ||
2396 | rhs = get_rhs (stmt); | |
2397 | if (!rhs || rhs == stmt) | |
2398 | return changed; | |
2399 | ||
2400 | new_rhs = fold (rhs); | |
ff09445d | 2401 | STRIP_USELESS_TYPE_CONVERSION (new_rhs); |
8171a1dd | 2402 | if (new_rhs == rhs) |
2403 | return changed; | |
2404 | ||
2405 | changed |= set_rhs (&stmt, new_rhs); | |
2406 | gcc_assert (stmt == old_stmt); | |
2407 | ||
2408 | return changed; | |
2409 | } | |
4ee9c684 | 2410 | \f |
909e5ecb | 2411 | /* Convert EXPR into a GIMPLE value suitable for substitution on the |
2412 | RHS of an assignment. Insert the necessary statements before | |
a280136a | 2413 | iterator *SI_P. |
2414 | When IGNORE is set, don't worry about the return value. */ | |
909e5ecb | 2415 | |
2416 | static tree | |
a280136a | 2417 | convert_to_gimple_builtin (block_stmt_iterator *si_p, tree expr, bool ignore) |
909e5ecb | 2418 | { |
2419 | tree_stmt_iterator ti; | |
2420 | tree stmt = bsi_stmt (*si_p); | |
2421 | tree tmp, stmts = NULL; | |
2422 | ||
2423 | push_gimplify_context (); | |
a280136a | 2424 | if (ignore) |
2425 | { | |
2426 | tmp = build_empty_stmt (); | |
2427 | gimplify_and_add (expr, &stmts); | |
2428 | } | |
2429 | else | |
2430 | tmp = get_initialized_tmp_var (expr, &stmts, NULL); | |
909e5ecb | 2431 | pop_gimplify_context (NULL); |
2432 | ||
b66731e8 | 2433 | if (EXPR_HAS_LOCATION (stmt)) |
2434 | annotate_all_with_locus (&stmts, EXPR_LOCATION (stmt)); | |
2435 | ||
909e5ecb | 2436 | /* The replacement can expose previously unreferenced variables. */ |
2437 | for (ti = tsi_start (stmts); !tsi_end_p (ti); tsi_next (&ti)) | |
2438 | { | |
b66731e8 | 2439 | tree new_stmt = tsi_stmt (ti); |
909e5ecb | 2440 | find_new_referenced_vars (tsi_stmt_ptr (ti)); |
b66731e8 | 2441 | bsi_insert_before (si_p, new_stmt, BSI_NEW_STMT); |
2442 | mark_new_vars_to_rename (bsi_stmt (*si_p)); | |
2443 | bsi_next (si_p); | |
909e5ecb | 2444 | } |
2445 | ||
909e5ecb | 2446 | return tmp; |
2447 | } | |
2448 | ||
2449 | ||
4ee9c684 | 2450 | /* A simple pass that attempts to fold all builtin functions. This pass |
2451 | is run after we've propagated as many constants as we can. */ | |
2452 | ||
2a1990e9 | 2453 | static unsigned int |
4ee9c684 | 2454 | execute_fold_all_builtins (void) |
2455 | { | |
b36237eb | 2456 | bool cfg_changed = false; |
4ee9c684 | 2457 | basic_block bb; |
2458 | FOR_EACH_BB (bb) | |
2459 | { | |
2460 | block_stmt_iterator i; | |
0a39fd54 | 2461 | for (i = bsi_start (bb); !bsi_end_p (i); ) |
4ee9c684 | 2462 | { |
2463 | tree *stmtp = bsi_stmt_ptr (i); | |
4c27dd45 | 2464 | tree old_stmt = *stmtp; |
4ee9c684 | 2465 | tree call = get_rhs (*stmtp); |
2466 | tree callee, result; | |
0a39fd54 | 2467 | enum built_in_function fcode; |
4ee9c684 | 2468 | |
2469 | if (!call || TREE_CODE (call) != CALL_EXPR) | |
0a39fd54 | 2470 | { |
2471 | bsi_next (&i); | |
2472 | continue; | |
2473 | } | |
4ee9c684 | 2474 | callee = get_callee_fndecl (call); |
2475 | if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) | |
0a39fd54 | 2476 | { |
2477 | bsi_next (&i); | |
2478 | continue; | |
2479 | } | |
2480 | fcode = DECL_FUNCTION_CODE (callee); | |
4ee9c684 | 2481 | |
2482 | result = ccp_fold_builtin (*stmtp, call); | |
2483 | if (!result) | |
2484 | switch (DECL_FUNCTION_CODE (callee)) | |
2485 | { | |
2486 | case BUILT_IN_CONSTANT_P: | |
2487 | /* Resolve __builtin_constant_p. If it hasn't been | |
2488 | folded to integer_one_node by now, it's fairly | |
2489 | certain that the value simply isn't constant. */ | |
2490 | result = integer_zero_node; | |
2491 | break; | |
2492 | ||
2493 | default: | |
0a39fd54 | 2494 | bsi_next (&i); |
4ee9c684 | 2495 | continue; |
2496 | } | |
2497 | ||
2498 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2499 | { | |
2500 | fprintf (dump_file, "Simplified\n "); | |
2501 | print_generic_stmt (dump_file, *stmtp, dump_flags); | |
2502 | } | |
2503 | ||
909e5ecb | 2504 | if (!set_rhs (stmtp, result)) |
2505 | { | |
a280136a | 2506 | result = convert_to_gimple_builtin (&i, result, |
2507 | TREE_CODE (old_stmt) | |
2508 | != MODIFY_EXPR); | |
876760f6 | 2509 | if (result) |
2510 | { | |
2511 | bool ok = set_rhs (stmtp, result); | |
2512 | ||
2513 | gcc_assert (ok); | |
2514 | } | |
909e5ecb | 2515 | } |
ca92b9d2 | 2516 | mark_new_vars_to_rename (*stmtp); |
4c27dd45 | 2517 | if (maybe_clean_or_replace_eh_stmt (old_stmt, *stmtp) |
b36237eb | 2518 | && tree_purge_dead_eh_edges (bb)) |
2519 | cfg_changed = true; | |
4ee9c684 | 2520 | |
2521 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2522 | { | |
2523 | fprintf (dump_file, "to\n "); | |
2524 | print_generic_stmt (dump_file, *stmtp, dump_flags); | |
2525 | fprintf (dump_file, "\n"); | |
2526 | } | |
0a39fd54 | 2527 | |
2528 | /* Retry the same statement if it changed into another | |
2529 | builtin, there might be new opportunities now. */ | |
2530 | call = get_rhs (*stmtp); | |
2531 | if (!call || TREE_CODE (call) != CALL_EXPR) | |
2532 | { | |
2533 | bsi_next (&i); | |
2534 | continue; | |
2535 | } | |
2536 | callee = get_callee_fndecl (call); | |
2537 | if (!callee | |
2538 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL | |
2539 | || DECL_FUNCTION_CODE (callee) == fcode) | |
2540 | bsi_next (&i); | |
4ee9c684 | 2541 | } |
2542 | } | |
b36237eb | 2543 | |
2544 | /* Delete unreachable blocks. */ | |
2545 | if (cfg_changed) | |
2546 | cleanup_tree_cfg (); | |
2a1990e9 | 2547 | return 0; |
4ee9c684 | 2548 | } |
2549 | ||
41511585 | 2550 | |
4ee9c684 | 2551 | struct tree_opt_pass pass_fold_builtins = |
2552 | { | |
2553 | "fab", /* name */ | |
2554 | NULL, /* gate */ | |
2555 | execute_fold_all_builtins, /* execute */ | |
2556 | NULL, /* sub */ | |
2557 | NULL, /* next */ | |
2558 | 0, /* static_pass_number */ | |
2559 | 0, /* tv_id */ | |
f45a1ca1 | 2560 | PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */ |
4ee9c684 | 2561 | 0, /* properties_provided */ |
2562 | 0, /* properties_destroyed */ | |
2563 | 0, /* todo_flags_start */ | |
909e5ecb | 2564 | TODO_dump_func |
2565 | | TODO_verify_ssa | |
88dbf20f | 2566 | | TODO_update_ssa, /* todo_flags_finish */ |
0f9005dd | 2567 | 0 /* letter */ |
4ee9c684 | 2568 | }; |