]>
Commit | Line | Data |
---|---|---|
6de9cd9a | 1 | /* Conditional constant propagation pass for the GNU compiler. |
b6f65e3c | 2 | Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006 |
1e052c19 | 3 | Free Software Foundation, Inc. |
6de9cd9a DN |
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 | |
366ccddb KC |
21 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA |
22 | 02110-1301, USA. */ | |
6de9cd9a | 23 | |
0bca51f0 DN |
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 | ||
106dec71 ZD |
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. | |
0bca51f0 DN |
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 | ||
106dec71 ZD |
151 | Note that the initial value of virtual operands is VARYING, not |
152 | UNDEFINED. Consider, for instance global variables: | |
0bca51f0 DN |
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 | |
106dec71 | 170 | would erroneously optimize the above into 'return 3;'. |
0bca51f0 DN |
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. | |
6de9cd9a DN |
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" | |
6de9cd9a | 194 | #include "tree.h" |
750628d8 | 195 | #include "flags.h" |
6de9cd9a DN |
196 | #include "rtl.h" |
197 | #include "tm_p.h" | |
750628d8 | 198 | #include "ggc.h" |
6de9cd9a | 199 | #include "basic-block.h" |
750628d8 | 200 | #include "output.h" |
750628d8 DN |
201 | #include "expr.h" |
202 | #include "function.h" | |
6de9cd9a | 203 | #include "diagnostic.h" |
750628d8 | 204 | #include "timevar.h" |
6de9cd9a | 205 | #include "tree-dump.h" |
750628d8 | 206 | #include "tree-flow.h" |
6de9cd9a | 207 | #include "tree-pass.h" |
750628d8 DN |
208 | #include "tree-ssa-propagate.h" |
209 | #include "langhooks.h" | |
ae3df618 | 210 | #include "target.h" |
6de9cd9a DN |
211 | |
212 | ||
213 | /* Possible lattice values. */ | |
214 | typedef enum | |
215 | { | |
106dec71 | 216 | UNINITIALIZED, |
6de9cd9a DN |
217 | UNDEFINED, |
218 | CONSTANT, | |
219 | VARYING | |
0bca51f0 | 220 | } ccp_lattice_t; |
6de9cd9a | 221 | |
0bca51f0 DN |
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). */ | |
404f4351 | 228 | static prop_value_t *const_val; |
6de9cd9a | 229 | |
0bca51f0 DN |
230 | /* True if we are also propagating constants in stores and loads. */ |
231 | static bool do_store_ccp; | |
6de9cd9a | 232 | |
0bca51f0 | 233 | /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */ |
95eec0d6 DB |
234 | |
235 | static void | |
0bca51f0 | 236 | dump_lattice_value (FILE *outf, const char *prefix, prop_value_t val) |
95eec0d6 | 237 | { |
750628d8 | 238 | switch (val.lattice_val) |
95eec0d6 | 239 | { |
0bca51f0 DN |
240 | case UNINITIALIZED: |
241 | fprintf (outf, "%sUNINITIALIZED", prefix); | |
242 | break; | |
750628d8 DN |
243 | case UNDEFINED: |
244 | fprintf (outf, "%sUNDEFINED", prefix); | |
245 | break; | |
246 | case VARYING: | |
247 | fprintf (outf, "%sVARYING", prefix); | |
248 | break; | |
750628d8 DN |
249 | case CONSTANT: |
250 | fprintf (outf, "%sCONSTANT ", prefix); | |
0bca51f0 | 251 | print_generic_expr (outf, val.value, dump_flags); |
750628d8 DN |
252 | break; |
253 | default: | |
1e128c5f | 254 | gcc_unreachable (); |
750628d8 | 255 | } |
95eec0d6 | 256 | } |
6de9cd9a | 257 | |
6de9cd9a | 258 | |
0bca51f0 DN |
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 | } | |
6de9cd9a | 269 | |
6de9cd9a | 270 | |
688e936d RH |
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 | |
6416ae7f | 274 | have to be more strict ourselves. */ |
688e936d RH |
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 | ||
fc9962ee ZD |
296 | /* If SYM is a constant variable with known value, return the value. |
297 | NULL_TREE is returned otherwise. */ | |
298 | ||
299 | static tree | |
300 | get_symbol_constant_value (tree sym) | |
301 | { | |
302 | if (TREE_STATIC (sym) | |
303 | && TREE_READONLY (sym) | |
304 | && !MTAG_P (sym)) | |
305 | { | |
306 | tree val = DECL_INITIAL (sym); | |
307 | if (val | |
308 | && ccp_decl_initial_min_invariant (val)) | |
309 | return val; | |
310 | } | |
311 | ||
312 | return NULL_TREE; | |
313 | } | |
688e936d | 314 | |
0bca51f0 DN |
315 | /* Compute a default value for variable VAR and store it in the |
316 | CONST_VAL array. The following rules are used to get default | |
317 | values: | |
95eec0d6 | 318 | |
0bca51f0 DN |
319 | 1- Global and static variables that are declared constant are |
320 | considered CONSTANT. | |
321 | ||
322 | 2- Any other value is considered UNDEFINED. This is useful when | |
750628d8 DN |
323 | considering PHI nodes. PHI arguments that are undefined do not |
324 | change the constant value of the PHI node, which allows for more | |
0bca51f0 | 325 | constants to be propagated. |
6de9cd9a | 326 | |
0bca51f0 DN |
327 | 3- If SSA_NAME_VALUE is set and it is a constant, its value is |
328 | used. | |
6de9cd9a | 329 | |
0bca51f0 DN |
330 | 4- Variables defined by statements other than assignments and PHI |
331 | nodes are considered VARYING. | |
6de9cd9a | 332 | |
106dec71 ZD |
333 | 5- Initial values of variables that are not GIMPLE registers are |
334 | considered VARYING. */ | |
6de9cd9a | 335 | |
0bca51f0 DN |
336 | static prop_value_t |
337 | get_default_value (tree var) | |
338 | { | |
339 | tree sym = SSA_NAME_VAR (var); | |
340 | prop_value_t val = { UNINITIALIZED, NULL_TREE, NULL_TREE }; | |
fc9962ee | 341 | tree cst_val; |
106dec71 | 342 | |
0bca51f0 | 343 | if (!do_store_ccp && !is_gimple_reg (var)) |
6de9cd9a | 344 | { |
0bca51f0 DN |
345 | /* Short circuit for regular CCP. We are not interested in any |
346 | non-register when DO_STORE_CCP is false. */ | |
750628d8 | 347 | val.lattice_val = VARYING; |
6de9cd9a | 348 | } |
0bca51f0 DN |
349 | else if (SSA_NAME_VALUE (var) |
350 | && is_gimple_min_invariant (SSA_NAME_VALUE (var))) | |
750628d8 | 351 | { |
0bca51f0 DN |
352 | val.lattice_val = CONSTANT; |
353 | val.value = SSA_NAME_VALUE (var); | |
750628d8 | 354 | } |
fc9962ee | 355 | else if ((cst_val = get_symbol_constant_value (sym)) != NULL_TREE) |
750628d8 | 356 | { |
0bca51f0 DN |
357 | /* Globals and static variables declared 'const' take their |
358 | initial value. */ | |
359 | val.lattice_val = CONSTANT; | |
fc9962ee | 360 | val.value = cst_val; |
0bca51f0 | 361 | val.mem_ref = sym; |
750628d8 DN |
362 | } |
363 | else | |
364 | { | |
750628d8 | 365 | tree stmt = SSA_NAME_DEF_STMT (var); |
6de9cd9a | 366 | |
0bca51f0 DN |
367 | if (IS_EMPTY_STMT (stmt)) |
368 | { | |
369 | /* Variables defined by an empty statement are those used | |
370 | before being initialized. If VAR is a local variable, we | |
106dec71 ZD |
371 | can assume initially that it is UNDEFINED, otherwise we must |
372 | consider it VARYING. */ | |
0bca51f0 DN |
373 | if (is_gimple_reg (sym) && TREE_CODE (sym) != PARM_DECL) |
374 | val.lattice_val = UNDEFINED; | |
0bca51f0 | 375 | else |
750628d8 DN |
376 | val.lattice_val = VARYING; |
377 | } | |
0bca51f0 DN |
378 | else if (TREE_CODE (stmt) == MODIFY_EXPR |
379 | || TREE_CODE (stmt) == PHI_NODE) | |
380 | { | |
381 | /* Any other variable defined by an assignment or a PHI node | |
106dec71 ZD |
382 | is considered UNDEFINED. */ |
383 | val.lattice_val = UNDEFINED; | |
0bca51f0 DN |
384 | } |
385 | else | |
386 | { | |
387 | /* Otherwise, VAR will never take on a constant value. */ | |
388 | val.lattice_val = VARYING; | |
389 | } | |
750628d8 | 390 | } |
6de9cd9a | 391 | |
750628d8 DN |
392 | return val; |
393 | } | |
6de9cd9a | 394 | |
6de9cd9a | 395 | |
106dec71 | 396 | /* Get the constant value associated with variable VAR. */ |
6de9cd9a | 397 | |
106dec71 ZD |
398 | static inline prop_value_t * |
399 | get_value (tree var) | |
0bca51f0 DN |
400 | { |
401 | prop_value_t *val = &const_val[SSA_NAME_VERSION (var)]; | |
106dec71 ZD |
402 | |
403 | if (val->lattice_val == UNINITIALIZED) | |
6de9cd9a DN |
404 | *val = get_default_value (var); |
405 | ||
406 | return val; | |
407 | } | |
408 | ||
106dec71 ZD |
409 | /* Sets the value associated with VAR to VARYING. */ |
410 | ||
411 | static inline void | |
412 | set_value_varying (tree var) | |
413 | { | |
414 | prop_value_t *val = &const_val[SSA_NAME_VERSION (var)]; | |
415 | ||
416 | val->lattice_val = VARYING; | |
417 | val->value = NULL_TREE; | |
418 | val->mem_ref = NULL_TREE; | |
419 | } | |
6de9cd9a | 420 | |
0bca51f0 DN |
421 | /* Set the value for variable VAR to NEW_VAL. Return true if the new |
422 | value is different from VAR's previous value. */ | |
6de9cd9a | 423 | |
750628d8 | 424 | static bool |
0bca51f0 | 425 | set_lattice_value (tree var, prop_value_t new_val) |
6de9cd9a | 426 | { |
106dec71 | 427 | prop_value_t *old_val = get_value (var); |
0bca51f0 DN |
428 | |
429 | /* Lattice transitions must always be monotonically increasing in | |
106dec71 ZD |
430 | value. If *OLD_VAL and NEW_VAL are the same, return false to |
431 | inform the caller that this was a non-transition. */ | |
432 | ||
fc9962ee | 433 | gcc_assert (old_val->lattice_val < new_val.lattice_val |
0bca51f0 | 434 | || (old_val->lattice_val == new_val.lattice_val |
fc9962ee ZD |
435 | && ((!old_val->value && !new_val.value) |
436 | || operand_equal_p (old_val->value, new_val.value, 0)) | |
106dec71 | 437 | && old_val->mem_ref == new_val.mem_ref)); |
0bca51f0 DN |
438 | |
439 | if (old_val->lattice_val != new_val.lattice_val) | |
6de9cd9a | 440 | { |
750628d8 DN |
441 | if (dump_file && (dump_flags & TDF_DETAILS)) |
442 | { | |
0bca51f0 | 443 | dump_lattice_value (dump_file, "Lattice value changed to ", new_val); |
106dec71 | 444 | fprintf (dump_file, ". Adding SSA edges to worklist.\n"); |
750628d8 DN |
445 | } |
446 | ||
0bca51f0 DN |
447 | *old_val = new_val; |
448 | ||
106dec71 ZD |
449 | gcc_assert (new_val.lattice_val != UNDEFINED); |
450 | return true; | |
6de9cd9a | 451 | } |
750628d8 DN |
452 | |
453 | return false; | |
6de9cd9a DN |
454 | } |
455 | ||
456 | ||
0bca51f0 | 457 | /* Return the likely CCP lattice value for STMT. |
6de9cd9a | 458 | |
750628d8 | 459 | If STMT has no operands, then return CONSTANT. |
6de9cd9a | 460 | |
750628d8 | 461 | Else if any operands of STMT are undefined, then return UNDEFINED. |
6de9cd9a | 462 | |
750628d8 | 463 | Else if any operands of STMT are constants, then return CONSTANT. |
6de9cd9a | 464 | |
750628d8 | 465 | Else return VARYING. */ |
6de9cd9a | 466 | |
0bca51f0 | 467 | static ccp_lattice_t |
750628d8 DN |
468 | likely_value (tree stmt) |
469 | { | |
106dec71 | 470 | bool has_constant_operand; |
750628d8 DN |
471 | stmt_ann_t ann; |
472 | tree use; | |
473 | ssa_op_iter iter; | |
6de9cd9a | 474 | |
750628d8 | 475 | ann = stmt_ann (stmt); |
0bca51f0 DN |
476 | |
477 | /* If the statement has volatile operands, it won't fold to a | |
478 | constant value. */ | |
479 | if (ann->has_volatile_ops) | |
480 | return VARYING; | |
481 | ||
482 | /* If we are not doing store-ccp, statements with loads | |
483 | and/or stores will never fold into a constant. */ | |
484 | if (!do_store_ccp | |
ff88c5aa | 485 | && !ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)) |
750628d8 | 486 | return VARYING; |
6de9cd9a | 487 | |
0bca51f0 DN |
488 | |
489 | /* A CALL_EXPR is assumed to be varying. NOTE: This may be overly | |
490 | conservative, in the presence of const and pure calls. */ | |
750628d8 DN |
491 | if (get_call_expr_in (stmt) != NULL_TREE) |
492 | return VARYING; | |
6de9cd9a | 493 | |
0bca51f0 DN |
494 | /* Anything other than assignments and conditional jumps are not |
495 | interesting for CCP. */ | |
496 | if (TREE_CODE (stmt) != MODIFY_EXPR | |
106dec71 | 497 | && !(TREE_CODE (stmt) == RETURN_EXPR && get_rhs (stmt) != NULL_TREE) |
0bca51f0 DN |
498 | && TREE_CODE (stmt) != COND_EXPR |
499 | && TREE_CODE (stmt) != SWITCH_EXPR) | |
500 | return VARYING; | |
501 | ||
a318e3ac SB |
502 | if (is_gimple_min_invariant (get_rhs (stmt))) |
503 | return CONSTANT; | |
504 | ||
106dec71 ZD |
505 | has_constant_operand = false; |
506 | FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE | SSA_OP_VUSE) | |
750628d8 | 507 | { |
106dec71 | 508 | prop_value_t *val = get_value (use); |
750628d8 | 509 | |
106dec71 ZD |
510 | if (val->lattice_val == UNDEFINED) |
511 | return UNDEFINED; | |
0bca51f0 | 512 | |
750628d8 | 513 | if (val->lattice_val == CONSTANT) |
106dec71 | 514 | has_constant_operand = true; |
6de9cd9a | 515 | } |
750628d8 | 516 | |
106dec71 ZD |
517 | if (has_constant_operand |
518 | /* We do not consider virtual operands here -- load from read-only | |
519 | memory may have only VARYING virtual operands, but still be | |
520 | constant. */ | |
521 | || ZERO_SSA_OPERANDS (stmt, SSA_OP_USE)) | |
0bca51f0 DN |
522 | return CONSTANT; |
523 | ||
106dec71 | 524 | return VARYING; |
6de9cd9a DN |
525 | } |
526 | ||
106dec71 ZD |
527 | /* Returns true if STMT cannot be constant. */ |
528 | ||
529 | static bool | |
530 | surely_varying_stmt_p (tree stmt) | |
531 | { | |
532 | /* If the statement has operands that we cannot handle, it cannot be | |
533 | constant. */ | |
534 | if (stmt_ann (stmt)->has_volatile_ops) | |
535 | return true; | |
536 | ||
537 | if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)) | |
538 | { | |
539 | if (!do_store_ccp) | |
540 | return true; | |
541 | ||
542 | /* We can only handle simple loads and stores. */ | |
543 | if (!stmt_makes_single_load (stmt) | |
544 | && !stmt_makes_single_store (stmt)) | |
545 | return true; | |
546 | } | |
547 | ||
548 | /* If it contains a call, it is varying. */ | |
549 | if (get_call_expr_in (stmt) != NULL_TREE) | |
550 | return true; | |
551 | ||
552 | /* Anything other than assignments and conditional jumps are not | |
553 | interesting for CCP. */ | |
554 | if (TREE_CODE (stmt) != MODIFY_EXPR | |
555 | && !(TREE_CODE (stmt) == RETURN_EXPR && get_rhs (stmt) != NULL_TREE) | |
556 | && TREE_CODE (stmt) != COND_EXPR | |
557 | && TREE_CODE (stmt) != SWITCH_EXPR) | |
558 | return true; | |
559 | ||
560 | return false; | |
561 | } | |
6de9cd9a | 562 | |
750628d8 | 563 | /* Initialize local data structures for CCP. */ |
6de9cd9a DN |
564 | |
565 | static void | |
750628d8 | 566 | ccp_initialize (void) |
6de9cd9a | 567 | { |
750628d8 | 568 | basic_block bb; |
6de9cd9a | 569 | |
b9eae1a9 | 570 | const_val = XCNEWVEC (prop_value_t, num_ssa_names); |
6de9cd9a | 571 | |
750628d8 DN |
572 | /* Initialize simulation flags for PHI nodes and statements. */ |
573 | FOR_EACH_BB (bb) | |
6de9cd9a | 574 | { |
750628d8 | 575 | block_stmt_iterator i; |
6de9cd9a | 576 | |
750628d8 DN |
577 | for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i)) |
578 | { | |
750628d8 | 579 | tree stmt = bsi_stmt (i); |
106dec71 | 580 | bool is_varying = surely_varying_stmt_p (stmt); |
6de9cd9a | 581 | |
106dec71 | 582 | if (is_varying) |
750628d8 | 583 | { |
0bca51f0 DN |
584 | tree def; |
585 | ssa_op_iter iter; | |
586 | ||
587 | /* If the statement will not produce a constant, mark | |
588 | all its outputs VARYING. */ | |
589 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) | |
106dec71 ZD |
590 | { |
591 | if (is_varying) | |
592 | set_value_varying (def); | |
593 | } | |
750628d8 DN |
594 | } |
595 | ||
750628d8 DN |
596 | DONT_SIMULATE_AGAIN (stmt) = is_varying; |
597 | } | |
6de9cd9a DN |
598 | } |
599 | ||
106dec71 ZD |
600 | /* Now process PHI nodes. We never set DONT_SIMULATE_AGAIN on phi node, |
601 | since we do not know which edges are executable yet, except for | |
602 | phi nodes for virtual operands when we do not do store ccp. */ | |
750628d8 | 603 | FOR_EACH_BB (bb) |
6de9cd9a | 604 | { |
0bca51f0 | 605 | tree phi; |
750628d8 DN |
606 | |
607 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) | |
608 | { | |
106dec71 ZD |
609 | if (!do_store_ccp && !is_gimple_reg (PHI_RESULT (phi))) |
610 | DONT_SIMULATE_AGAIN (phi) = true; | |
611 | else | |
612 | DONT_SIMULATE_AGAIN (phi) = false; | |
750628d8 | 613 | } |
6de9cd9a | 614 | } |
750628d8 | 615 | } |
6de9cd9a | 616 | |
6de9cd9a | 617 | |
0bca51f0 DN |
618 | /* Do final substitution of propagated values, cleanup the flowgraph and |
619 | free allocated storage. */ | |
6de9cd9a | 620 | |
0bca51f0 DN |
621 | static void |
622 | ccp_finalize (void) | |
6de9cd9a | 623 | { |
0bca51f0 | 624 | /* Perform substitutions based on the known constant values. */ |
227858d1 | 625 | substitute_and_fold (const_val, false); |
6de9cd9a | 626 | |
0bca51f0 | 627 | free (const_val); |
6de9cd9a DN |
628 | } |
629 | ||
630 | ||
0bca51f0 DN |
631 | /* Compute the meet operator between *VAL1 and *VAL2. Store the result |
632 | in VAL1. | |
633 | ||
634 | any M UNDEFINED = any | |
0bca51f0 DN |
635 | any M VARYING = VARYING |
636 | Ci M Cj = Ci if (i == j) | |
637 | Ci M Cj = VARYING if (i != j) | |
106dec71 | 638 | */ |
6de9cd9a DN |
639 | |
640 | static void | |
0bca51f0 | 641 | ccp_lattice_meet (prop_value_t *val1, prop_value_t *val2) |
6de9cd9a | 642 | { |
0bca51f0 | 643 | if (val1->lattice_val == UNDEFINED) |
6de9cd9a | 644 | { |
0bca51f0 DN |
645 | /* UNDEFINED M any = any */ |
646 | *val1 = *val2; | |
750628d8 | 647 | } |
0bca51f0 | 648 | else if (val2->lattice_val == UNDEFINED) |
195da47b | 649 | { |
0bca51f0 DN |
650 | /* any M UNDEFINED = any |
651 | Nothing to do. VAL1 already contains the value we want. */ | |
652 | ; | |
195da47b | 653 | } |
0bca51f0 DN |
654 | else if (val1->lattice_val == VARYING |
655 | || val2->lattice_val == VARYING) | |
750628d8 | 656 | { |
0bca51f0 DN |
657 | /* any M VARYING = VARYING. */ |
658 | val1->lattice_val = VARYING; | |
659 | val1->value = NULL_TREE; | |
660 | val1->mem_ref = NULL_TREE; | |
750628d8 | 661 | } |
0bca51f0 DN |
662 | else if (val1->lattice_val == CONSTANT |
663 | && val2->lattice_val == CONSTANT | |
664 | && simple_cst_equal (val1->value, val2->value) == 1 | |
665 | && (!do_store_ccp | |
a318e3ac SB |
666 | || (val1->mem_ref && val2->mem_ref |
667 | && operand_equal_p (val1->mem_ref, val2->mem_ref, 0)))) | |
750628d8 | 668 | { |
0bca51f0 DN |
669 | /* Ci M Cj = Ci if (i == j) |
670 | Ci M Cj = VARYING if (i != j) | |
671 | ||
672 | If these two values come from memory stores, make sure that | |
673 | they come from the same memory reference. */ | |
674 | val1->lattice_val = CONSTANT; | |
675 | val1->value = val1->value; | |
676 | val1->mem_ref = val1->mem_ref; | |
750628d8 DN |
677 | } |
678 | else | |
679 | { | |
0bca51f0 DN |
680 | /* Any other combination is VARYING. */ |
681 | val1->lattice_val = VARYING; | |
682 | val1->value = NULL_TREE; | |
683 | val1->mem_ref = NULL_TREE; | |
750628d8 | 684 | } |
6de9cd9a DN |
685 | } |
686 | ||
687 | ||
750628d8 DN |
688 | /* Loop through the PHI_NODE's parameters for BLOCK and compare their |
689 | lattice values to determine PHI_NODE's lattice value. The value of a | |
0bca51f0 | 690 | PHI node is determined calling ccp_lattice_meet with all the arguments |
750628d8 | 691 | of the PHI node that are incoming via executable edges. */ |
6de9cd9a | 692 | |
750628d8 DN |
693 | static enum ssa_prop_result |
694 | ccp_visit_phi_node (tree phi) | |
6de9cd9a | 695 | { |
750628d8 | 696 | int i; |
0bca51f0 | 697 | prop_value_t *old_val, new_val; |
6de9cd9a | 698 | |
750628d8 | 699 | if (dump_file && (dump_flags & TDF_DETAILS)) |
6de9cd9a | 700 | { |
750628d8 DN |
701 | fprintf (dump_file, "\nVisiting PHI node: "); |
702 | print_generic_expr (dump_file, phi, dump_flags); | |
6de9cd9a | 703 | } |
6de9cd9a | 704 | |
106dec71 | 705 | old_val = get_value (PHI_RESULT (phi)); |
750628d8 DN |
706 | switch (old_val->lattice_val) |
707 | { | |
708 | case VARYING: | |
0bca51f0 | 709 | return SSA_PROP_VARYING; |
6de9cd9a | 710 | |
750628d8 DN |
711 | case CONSTANT: |
712 | new_val = *old_val; | |
713 | break; | |
6de9cd9a | 714 | |
750628d8 | 715 | case UNDEFINED: |
750628d8 | 716 | new_val.lattice_val = UNDEFINED; |
0bca51f0 DN |
717 | new_val.value = NULL_TREE; |
718 | new_val.mem_ref = NULL_TREE; | |
750628d8 | 719 | break; |
6de9cd9a | 720 | |
750628d8 | 721 | default: |
1e128c5f | 722 | gcc_unreachable (); |
750628d8 | 723 | } |
6de9cd9a | 724 | |
750628d8 DN |
725 | for (i = 0; i < PHI_NUM_ARGS (phi); i++) |
726 | { | |
0bca51f0 DN |
727 | /* Compute the meet operator over all the PHI arguments flowing |
728 | through executable edges. */ | |
750628d8 | 729 | edge e = PHI_ARG_EDGE (phi, i); |
6de9cd9a | 730 | |
750628d8 DN |
731 | if (dump_file && (dump_flags & TDF_DETAILS)) |
732 | { | |
733 | fprintf (dump_file, | |
734 | "\n Argument #%d (%d -> %d %sexecutable)\n", | |
735 | i, e->src->index, e->dest->index, | |
736 | (e->flags & EDGE_EXECUTABLE) ? "" : "not "); | |
737 | } | |
738 | ||
739 | /* If the incoming edge is executable, Compute the meet operator for | |
740 | the existing value of the PHI node and the current PHI argument. */ | |
741 | if (e->flags & EDGE_EXECUTABLE) | |
742 | { | |
0bca51f0 DN |
743 | tree arg = PHI_ARG_DEF (phi, i); |
744 | prop_value_t arg_val; | |
6de9cd9a | 745 | |
0bca51f0 | 746 | if (is_gimple_min_invariant (arg)) |
750628d8 | 747 | { |
0bca51f0 DN |
748 | arg_val.lattice_val = CONSTANT; |
749 | arg_val.value = arg; | |
750 | arg_val.mem_ref = NULL_TREE; | |
750628d8 DN |
751 | } |
752 | else | |
106dec71 | 753 | arg_val = *(get_value (arg)); |
6de9cd9a | 754 | |
0bca51f0 | 755 | ccp_lattice_meet (&new_val, &arg_val); |
6de9cd9a | 756 | |
750628d8 DN |
757 | if (dump_file && (dump_flags & TDF_DETAILS)) |
758 | { | |
759 | fprintf (dump_file, "\t"); | |
0bca51f0 DN |
760 | print_generic_expr (dump_file, arg, dump_flags); |
761 | dump_lattice_value (dump_file, "\tValue: ", arg_val); | |
750628d8 DN |
762 | fprintf (dump_file, "\n"); |
763 | } | |
6de9cd9a | 764 | |
750628d8 DN |
765 | if (new_val.lattice_val == VARYING) |
766 | break; | |
767 | } | |
768 | } | |
6de9cd9a DN |
769 | |
770 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
750628d8 DN |
771 | { |
772 | dump_lattice_value (dump_file, "\n PHI node value: ", new_val); | |
773 | fprintf (dump_file, "\n\n"); | |
774 | } | |
775 | ||
106dec71 | 776 | /* Make the transition to the new value. */ |
750628d8 DN |
777 | if (set_lattice_value (PHI_RESULT (phi), new_val)) |
778 | { | |
779 | if (new_val.lattice_val == VARYING) | |
780 | return SSA_PROP_VARYING; | |
781 | else | |
782 | return SSA_PROP_INTERESTING; | |
783 | } | |
784 | else | |
785 | return SSA_PROP_NOT_INTERESTING; | |
6de9cd9a DN |
786 | } |
787 | ||
788 | ||
750628d8 DN |
789 | /* CCP specific front-end to the non-destructive constant folding |
790 | routines. | |
6de9cd9a DN |
791 | |
792 | Attempt to simplify the RHS of STMT knowing that one or more | |
793 | operands are constants. | |
794 | ||
795 | If simplification is possible, return the simplified RHS, | |
796 | otherwise return the original RHS. */ | |
797 | ||
798 | static tree | |
799 | ccp_fold (tree stmt) | |
800 | { | |
801 | tree rhs = get_rhs (stmt); | |
802 | enum tree_code code = TREE_CODE (rhs); | |
6615c446 | 803 | enum tree_code_class kind = TREE_CODE_CLASS (code); |
6de9cd9a DN |
804 | tree retval = NULL_TREE; |
805 | ||
6de9cd9a | 806 | if (TREE_CODE (rhs) == SSA_NAME) |
0bca51f0 DN |
807 | { |
808 | /* If the RHS is an SSA_NAME, return its known constant value, | |
809 | if any. */ | |
106dec71 | 810 | return get_value (rhs)->value; |
0bca51f0 DN |
811 | } |
812 | else if (do_store_ccp && stmt_makes_single_load (stmt)) | |
813 | { | |
814 | /* If the RHS is a memory load, see if the VUSEs associated with | |
815 | it are a valid constant for that memory load. */ | |
816 | prop_value_t *val = get_value_loaded_by (stmt, const_val); | |
add9e6d3 AP |
817 | if (val && val->mem_ref) |
818 | { | |
819 | if (operand_equal_p (val->mem_ref, rhs, 0)) | |
820 | return val->value; | |
821 | ||
822 | /* If RHS is extracting REALPART_EXPR or IMAGPART_EXPR of a | |
823 | complex type with a known constant value, return it. */ | |
824 | if ((TREE_CODE (rhs) == REALPART_EXPR | |
825 | || TREE_CODE (rhs) == IMAGPART_EXPR) | |
826 | && operand_equal_p (val->mem_ref, TREE_OPERAND (rhs, 0), 0)) | |
827 | return fold_build1 (TREE_CODE (rhs), TREE_TYPE (rhs), val->value); | |
828 | } | |
829 | return NULL_TREE; | |
0bca51f0 | 830 | } |
6de9cd9a DN |
831 | |
832 | /* Unary operators. Note that we know the single operand must | |
833 | be a constant. So this should almost always return a | |
834 | simplified RHS. */ | |
6615c446 | 835 | if (kind == tcc_unary) |
6de9cd9a DN |
836 | { |
837 | /* Handle unary operators which can appear in GIMPLE form. */ | |
838 | tree op0 = TREE_OPERAND (rhs, 0); | |
839 | ||
840 | /* Simplify the operand down to a constant. */ | |
841 | if (TREE_CODE (op0) == SSA_NAME) | |
842 | { | |
106dec71 | 843 | prop_value_t *val = get_value (op0); |
6de9cd9a | 844 | if (val->lattice_val == CONSTANT) |
106dec71 | 845 | op0 = get_value (op0)->value; |
6de9cd9a DN |
846 | } |
847 | ||
078152a2 JH |
848 | if ((code == NOP_EXPR || code == CONVERT_EXPR) |
849 | && tree_ssa_useless_type_conversion_1 (TREE_TYPE (rhs), | |
850 | TREE_TYPE (op0))) | |
851 | return op0; | |
615bc06a | 852 | return fold_unary (code, TREE_TYPE (rhs), op0); |
6de9cd9a DN |
853 | } |
854 | ||
855 | /* Binary and comparison operators. We know one or both of the | |
856 | operands are constants. */ | |
6615c446 JO |
857 | else if (kind == tcc_binary |
858 | || kind == tcc_comparison | |
6de9cd9a DN |
859 | || code == TRUTH_AND_EXPR |
860 | || code == TRUTH_OR_EXPR | |
861 | || code == TRUTH_XOR_EXPR) | |
862 | { | |
863 | /* Handle binary and comparison operators that can appear in | |
864 | GIMPLE form. */ | |
865 | tree op0 = TREE_OPERAND (rhs, 0); | |
866 | tree op1 = TREE_OPERAND (rhs, 1); | |
867 | ||
868 | /* Simplify the operands down to constants when appropriate. */ | |
869 | if (TREE_CODE (op0) == SSA_NAME) | |
870 | { | |
106dec71 | 871 | prop_value_t *val = get_value (op0); |
6de9cd9a | 872 | if (val->lattice_val == CONSTANT) |
0bca51f0 | 873 | op0 = val->value; |
6de9cd9a DN |
874 | } |
875 | ||
876 | if (TREE_CODE (op1) == SSA_NAME) | |
877 | { | |
106dec71 | 878 | prop_value_t *val = get_value (op1); |
6de9cd9a | 879 | if (val->lattice_val == CONSTANT) |
0bca51f0 | 880 | op1 = val->value; |
6de9cd9a DN |
881 | } |
882 | ||
615bc06a | 883 | return fold_binary (code, TREE_TYPE (rhs), op0, op1); |
6de9cd9a DN |
884 | } |
885 | ||
886 | /* We may be able to fold away calls to builtin functions if their | |
9cf737f8 | 887 | arguments are constants. */ |
6de9cd9a DN |
888 | else if (code == CALL_EXPR |
889 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == ADDR_EXPR | |
890 | && (TREE_CODE (TREE_OPERAND (TREE_OPERAND (rhs, 0), 0)) | |
891 | == FUNCTION_DECL) | |
892 | && DECL_BUILT_IN (TREE_OPERAND (TREE_OPERAND (rhs, 0), 0))) | |
893 | { | |
f47c96aa | 894 | if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_USE)) |
6de9cd9a | 895 | { |
f47c96aa | 896 | tree *orig, var; |
49d1af89 | 897 | tree fndecl, arglist; |
f47c96aa AM |
898 | size_t i = 0; |
899 | ssa_op_iter iter; | |
900 | use_operand_p var_p; | |
6de9cd9a DN |
901 | |
902 | /* Preserve the original values of every operand. */ | |
858904db | 903 | orig = XNEWVEC (tree, NUM_SSA_OPERANDS (stmt, SSA_OP_USE)); |
f47c96aa AM |
904 | FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_USE) |
905 | orig[i++] = var; | |
6de9cd9a DN |
906 | |
907 | /* Substitute operands with their values and try to fold. */ | |
0bca51f0 | 908 | replace_uses_in (stmt, NULL, const_val); |
49d1af89 KH |
909 | fndecl = get_callee_fndecl (rhs); |
910 | arglist = TREE_OPERAND (rhs, 1); | |
911 | retval = fold_builtin (fndecl, arglist, false); | |
6de9cd9a DN |
912 | |
913 | /* Restore operands to their original form. */ | |
f47c96aa AM |
914 | i = 0; |
915 | FOR_EACH_SSA_USE_OPERAND (var_p, stmt, iter, SSA_OP_USE) | |
916 | SET_USE (var_p, orig[i++]); | |
6de9cd9a DN |
917 | free (orig); |
918 | } | |
919 | } | |
920 | else | |
921 | return rhs; | |
922 | ||
923 | /* If we got a simplified form, see if we need to convert its type. */ | |
924 | if (retval) | |
a32e70c3 | 925 | return fold_convert (TREE_TYPE (rhs), retval); |
6de9cd9a DN |
926 | |
927 | /* No simplification was possible. */ | |
928 | return rhs; | |
929 | } | |
930 | ||
931 | ||
ae3df618 SB |
932 | /* Return the tree representing the element referenced by T if T is an |
933 | ARRAY_REF or COMPONENT_REF into constant aggregates. Return | |
934 | NULL_TREE otherwise. */ | |
935 | ||
936 | static tree | |
937 | fold_const_aggregate_ref (tree t) | |
938 | { | |
939 | prop_value_t *value; | |
4038c495 GB |
940 | tree base, ctor, idx, field; |
941 | unsigned HOST_WIDE_INT cnt; | |
942 | tree cfield, cval; | |
ae3df618 SB |
943 | |
944 | switch (TREE_CODE (t)) | |
945 | { | |
946 | case ARRAY_REF: | |
947 | /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its | |
948 | DECL_INITIAL. If BASE is a nested reference into another | |
949 | ARRAY_REF or COMPONENT_REF, make a recursive call to resolve | |
950 | the inner reference. */ | |
951 | base = TREE_OPERAND (t, 0); | |
952 | switch (TREE_CODE (base)) | |
953 | { | |
954 | case VAR_DECL: | |
955 | if (!TREE_READONLY (base) | |
956 | || TREE_CODE (TREE_TYPE (base)) != ARRAY_TYPE | |
957 | || !targetm.binds_local_p (base)) | |
958 | return NULL_TREE; | |
959 | ||
960 | ctor = DECL_INITIAL (base); | |
961 | break; | |
962 | ||
963 | case ARRAY_REF: | |
964 | case COMPONENT_REF: | |
965 | ctor = fold_const_aggregate_ref (base); | |
966 | break; | |
967 | ||
968 | default: | |
969 | return NULL_TREE; | |
970 | } | |
971 | ||
972 | if (ctor == NULL_TREE | |
faaf1436 RG |
973 | || (TREE_CODE (ctor) != CONSTRUCTOR |
974 | && TREE_CODE (ctor) != STRING_CST) | |
ae3df618 SB |
975 | || !TREE_STATIC (ctor)) |
976 | return NULL_TREE; | |
977 | ||
978 | /* Get the index. If we have an SSA_NAME, try to resolve it | |
979 | with the current lattice value for the SSA_NAME. */ | |
980 | idx = TREE_OPERAND (t, 1); | |
981 | switch (TREE_CODE (idx)) | |
982 | { | |
983 | case SSA_NAME: | |
106dec71 | 984 | if ((value = get_value (idx)) |
ae3df618 SB |
985 | && value->lattice_val == CONSTANT |
986 | && TREE_CODE (value->value) == INTEGER_CST) | |
987 | idx = value->value; | |
988 | else | |
989 | return NULL_TREE; | |
990 | break; | |
991 | ||
992 | case INTEGER_CST: | |
993 | break; | |
994 | ||
995 | default: | |
996 | return NULL_TREE; | |
997 | } | |
998 | ||
faaf1436 RG |
999 | /* Fold read from constant string. */ |
1000 | if (TREE_CODE (ctor) == STRING_CST) | |
1001 | { | |
1002 | if ((TYPE_MODE (TREE_TYPE (t)) | |
1003 | == TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1004 | && (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1005 | == MODE_INT) | |
1006 | && GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) == 1 | |
1007 | && compare_tree_int (idx, TREE_STRING_LENGTH (ctor)) < 0) | |
1008 | return build_int_cst (TREE_TYPE (t), (TREE_STRING_POINTER (ctor) | |
1009 | [TREE_INT_CST_LOW (idx)])); | |
1010 | return NULL_TREE; | |
1011 | } | |
1012 | ||
ae3df618 | 1013 | /* Whoo-hoo! I'll fold ya baby. Yeah! */ |
4038c495 GB |
1014 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) |
1015 | if (tree_int_cst_equal (cfield, idx)) | |
1016 | return cval; | |
ae3df618 SB |
1017 | break; |
1018 | ||
1019 | case COMPONENT_REF: | |
1020 | /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its | |
1021 | DECL_INITIAL. If BASE is a nested reference into another | |
1022 | ARRAY_REF or COMPONENT_REF, make a recursive call to resolve | |
1023 | the inner reference. */ | |
1024 | base = TREE_OPERAND (t, 0); | |
1025 | switch (TREE_CODE (base)) | |
1026 | { | |
1027 | case VAR_DECL: | |
1028 | if (!TREE_READONLY (base) | |
1029 | || TREE_CODE (TREE_TYPE (base)) != RECORD_TYPE | |
1030 | || !targetm.binds_local_p (base)) | |
1031 | return NULL_TREE; | |
1032 | ||
1033 | ctor = DECL_INITIAL (base); | |
1034 | break; | |
1035 | ||
1036 | case ARRAY_REF: | |
1037 | case COMPONENT_REF: | |
1038 | ctor = fold_const_aggregate_ref (base); | |
1039 | break; | |
1040 | ||
1041 | default: | |
1042 | return NULL_TREE; | |
1043 | } | |
1044 | ||
1045 | if (ctor == NULL_TREE | |
1046 | || TREE_CODE (ctor) != CONSTRUCTOR | |
1047 | || !TREE_STATIC (ctor)) | |
1048 | return NULL_TREE; | |
1049 | ||
1050 | field = TREE_OPERAND (t, 1); | |
1051 | ||
4038c495 GB |
1052 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) |
1053 | if (cfield == field | |
ae3df618 | 1054 | /* FIXME: Handle bit-fields. */ |
4038c495 GB |
1055 | && ! DECL_BIT_FIELD (cfield)) |
1056 | return cval; | |
ae3df618 SB |
1057 | break; |
1058 | ||
1ebd8d9a SB |
1059 | case REALPART_EXPR: |
1060 | case IMAGPART_EXPR: | |
1061 | { | |
1062 | tree c = fold_const_aggregate_ref (TREE_OPERAND (t, 0)); | |
1063 | if (c && TREE_CODE (c) == COMPLEX_CST) | |
1064 | return fold_build1 (TREE_CODE (t), TREE_TYPE (t), c); | |
1065 | break; | |
1066 | } | |
1067 | ||
ae3df618 SB |
1068 | default: |
1069 | break; | |
1070 | } | |
1071 | ||
1072 | return NULL_TREE; | |
1073 | } | |
1074 | ||
6de9cd9a DN |
1075 | /* Evaluate statement STMT. */ |
1076 | ||
0bca51f0 | 1077 | static prop_value_t |
6de9cd9a DN |
1078 | evaluate_stmt (tree stmt) |
1079 | { | |
0bca51f0 | 1080 | prop_value_t val; |
faaf1436 | 1081 | tree simplified = NULL_TREE; |
0bca51f0 DN |
1082 | ccp_lattice_t likelyvalue = likely_value (stmt); |
1083 | ||
1084 | val.mem_ref = NULL_TREE; | |
6de9cd9a DN |
1085 | |
1086 | /* If the statement is likely to have a CONSTANT result, then try | |
1087 | to fold the statement to determine the constant value. */ | |
1088 | if (likelyvalue == CONSTANT) | |
1089 | simplified = ccp_fold (stmt); | |
1090 | /* If the statement is likely to have a VARYING result, then do not | |
1091 | bother folding the statement. */ | |
faaf1436 | 1092 | if (likelyvalue == VARYING) |
6de9cd9a | 1093 | simplified = get_rhs (stmt); |
ae3df618 SB |
1094 | /* If the statement is an ARRAY_REF or COMPONENT_REF into constant |
1095 | aggregates, extract the referenced constant. Otherwise the | |
1096 | statement is likely to have an UNDEFINED value, and there will be | |
1097 | nothing to do. Note that fold_const_aggregate_ref returns | |
1098 | NULL_TREE if the first case does not match. */ | |
faaf1436 | 1099 | else if (!simplified) |
ae3df618 | 1100 | simplified = fold_const_aggregate_ref (get_rhs (stmt)); |
6de9cd9a DN |
1101 | |
1102 | if (simplified && is_gimple_min_invariant (simplified)) | |
1103 | { | |
1104 | /* The statement produced a constant value. */ | |
1105 | val.lattice_val = CONSTANT; | |
0bca51f0 | 1106 | val.value = simplified; |
6de9cd9a DN |
1107 | } |
1108 | else | |
1109 | { | |
1110 | /* The statement produced a nonconstant value. If the statement | |
0bca51f0 DN |
1111 | had UNDEFINED operands, then the result of the statement |
1112 | should be UNDEFINED. Otherwise, the statement is VARYING. */ | |
106dec71 | 1113 | if (likelyvalue == UNDEFINED) |
a318e3ac SB |
1114 | val.lattice_val = likelyvalue; |
1115 | else | |
1116 | val.lattice_val = VARYING; | |
1117 | ||
0bca51f0 | 1118 | val.value = NULL_TREE; |
6de9cd9a | 1119 | } |
750628d8 DN |
1120 | |
1121 | return val; | |
6de9cd9a DN |
1122 | } |
1123 | ||
1124 | ||
750628d8 | 1125 | /* Visit the assignment statement STMT. Set the value of its LHS to the |
0bca51f0 DN |
1126 | value computed by the RHS and store LHS in *OUTPUT_P. If STMT |
1127 | creates virtual definitions, set the value of each new name to that | |
1128 | of the RHS (if we can derive a constant out of the RHS). */ | |
6de9cd9a | 1129 | |
750628d8 DN |
1130 | static enum ssa_prop_result |
1131 | visit_assignment (tree stmt, tree *output_p) | |
6de9cd9a | 1132 | { |
0bca51f0 | 1133 | prop_value_t val; |
750628d8 | 1134 | tree lhs, rhs; |
0bca51f0 | 1135 | enum ssa_prop_result retval; |
6de9cd9a | 1136 | |
750628d8 DN |
1137 | lhs = TREE_OPERAND (stmt, 0); |
1138 | rhs = TREE_OPERAND (stmt, 1); | |
6de9cd9a | 1139 | |
750628d8 DN |
1140 | if (TREE_CODE (rhs) == SSA_NAME) |
1141 | { | |
1142 | /* For a simple copy operation, we copy the lattice values. */ | |
106dec71 | 1143 | prop_value_t *nval = get_value (rhs); |
750628d8 DN |
1144 | val = *nval; |
1145 | } | |
0bca51f0 | 1146 | else if (do_store_ccp && stmt_makes_single_load (stmt)) |
750628d8 | 1147 | { |
0bca51f0 | 1148 | /* Same as above, but the RHS is not a gimple register and yet |
106dec71 | 1149 | has a known VUSE. If STMT is loading from the same memory |
0bca51f0 DN |
1150 | location that created the SSA_NAMEs for the virtual operands, |
1151 | we can propagate the value on the RHS. */ | |
1152 | prop_value_t *nval = get_value_loaded_by (stmt, const_val); | |
1153 | ||
106dec71 ZD |
1154 | if (nval |
1155 | && nval->mem_ref | |
a318e3ac | 1156 | && operand_equal_p (nval->mem_ref, rhs, 0)) |
0bca51f0 DN |
1157 | val = *nval; |
1158 | else | |
1159 | val = evaluate_stmt (stmt); | |
750628d8 DN |
1160 | } |
1161 | else | |
9390c347 | 1162 | /* Evaluate the statement. */ |
750628d8 | 1163 | val = evaluate_stmt (stmt); |
6de9cd9a | 1164 | |
9390c347 | 1165 | /* If the original LHS was a VIEW_CONVERT_EXPR, modify the constant |
ae95537a | 1166 | value to be a VIEW_CONVERT_EXPR of the old constant value. |
9390c347 RK |
1167 | |
1168 | ??? Also, if this was a definition of a bitfield, we need to widen | |
750628d8 DN |
1169 | the constant value into the type of the destination variable. This |
1170 | should not be necessary if GCC represented bitfields properly. */ | |
1171 | { | |
9390c347 RK |
1172 | tree orig_lhs = TREE_OPERAND (stmt, 0); |
1173 | ||
1174 | if (TREE_CODE (orig_lhs) == VIEW_CONVERT_EXPR | |
1175 | && val.lattice_val == CONSTANT) | |
1176 | { | |
0dd4b47b KH |
1177 | tree w = fold_unary (VIEW_CONVERT_EXPR, |
1178 | TREE_TYPE (TREE_OPERAND (orig_lhs, 0)), | |
1179 | val.value); | |
ae95537a | 1180 | |
3d36fb45 | 1181 | orig_lhs = TREE_OPERAND (orig_lhs, 0); |
ae95537a | 1182 | if (w && is_gimple_min_invariant (w)) |
0bca51f0 | 1183 | val.value = w; |
ae95537a RK |
1184 | else |
1185 | { | |
1186 | val.lattice_val = VARYING; | |
0bca51f0 | 1187 | val.value = NULL; |
ae95537a | 1188 | } |
9390c347 RK |
1189 | } |
1190 | ||
750628d8 | 1191 | if (val.lattice_val == CONSTANT |
9390c347 RK |
1192 | && TREE_CODE (orig_lhs) == COMPONENT_REF |
1193 | && DECL_BIT_FIELD (TREE_OPERAND (orig_lhs, 1))) | |
6de9cd9a | 1194 | { |
0bca51f0 | 1195 | tree w = widen_bitfield (val.value, TREE_OPERAND (orig_lhs, 1), |
9390c347 | 1196 | orig_lhs); |
750628d8 DN |
1197 | |
1198 | if (w && is_gimple_min_invariant (w)) | |
0bca51f0 | 1199 | val.value = w; |
750628d8 | 1200 | else |
6de9cd9a | 1201 | { |
750628d8 | 1202 | val.lattice_val = VARYING; |
0bca51f0 DN |
1203 | val.value = NULL_TREE; |
1204 | val.mem_ref = NULL_TREE; | |
6de9cd9a | 1205 | } |
6de9cd9a | 1206 | } |
750628d8 | 1207 | } |
6de9cd9a | 1208 | |
0bca51f0 | 1209 | retval = SSA_PROP_NOT_INTERESTING; |
6de9cd9a | 1210 | |
750628d8 | 1211 | /* Set the lattice value of the statement's output. */ |
0bca51f0 | 1212 | if (TREE_CODE (lhs) == SSA_NAME) |
6de9cd9a | 1213 | { |
0bca51f0 DN |
1214 | /* If STMT is an assignment to an SSA_NAME, we only have one |
1215 | value to set. */ | |
1216 | if (set_lattice_value (lhs, val)) | |
1217 | { | |
1218 | *output_p = lhs; | |
1219 | if (val.lattice_val == VARYING) | |
1220 | retval = SSA_PROP_VARYING; | |
1221 | else | |
1222 | retval = SSA_PROP_INTERESTING; | |
1223 | } | |
6de9cd9a | 1224 | } |
0bca51f0 DN |
1225 | else if (do_store_ccp && stmt_makes_single_store (stmt)) |
1226 | { | |
1227 | /* Otherwise, set the names in V_MAY_DEF/V_MUST_DEF operands | |
1228 | to the new constant value and mark the LHS as the memory | |
1229 | reference associated with VAL. */ | |
1230 | ssa_op_iter i; | |
1231 | tree vdef; | |
1232 | bool changed; | |
1233 | ||
0bca51f0 | 1234 | /* Mark VAL as stored in the LHS of this assignment. */ |
106dec71 ZD |
1235 | if (val.lattice_val == CONSTANT) |
1236 | val.mem_ref = lhs; | |
0bca51f0 DN |
1237 | |
1238 | /* Set the value of every VDEF to VAL. */ | |
1239 | changed = false; | |
1240 | FOR_EACH_SSA_TREE_OPERAND (vdef, stmt, i, SSA_OP_VIRTUAL_DEFS) | |
fc9962ee ZD |
1241 | { |
1242 | /* See PR 29801. We may have VDEFs for read-only variables | |
1243 | (see the handling of unmodifiable variables in | |
1244 | add_virtual_operand); do not attempt to change their value. */ | |
1245 | if (get_symbol_constant_value (SSA_NAME_VAR (vdef)) != NULL_TREE) | |
1246 | continue; | |
1247 | ||
1248 | changed |= set_lattice_value (vdef, val); | |
1249 | } | |
0bca51f0 DN |
1250 | |
1251 | /* Note that for propagation purposes, we are only interested in | |
1252 | visiting statements that load the exact same memory reference | |
1253 | stored here. Those statements will have the exact same list | |
1254 | of virtual uses, so it is enough to set the output of this | |
1255 | statement to be its first virtual definition. */ | |
1256 | *output_p = first_vdef (stmt); | |
1257 | if (changed) | |
1258 | { | |
1259 | if (val.lattice_val == VARYING) | |
1260 | retval = SSA_PROP_VARYING; | |
1261 | else | |
1262 | retval = SSA_PROP_INTERESTING; | |
1263 | } | |
1264 | } | |
1265 | ||
1266 | return retval; | |
6de9cd9a DN |
1267 | } |
1268 | ||
6de9cd9a | 1269 | |
750628d8 DN |
1270 | /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING |
1271 | if it can determine which edge will be taken. Otherwise, return | |
1272 | SSA_PROP_VARYING. */ | |
1273 | ||
1274 | static enum ssa_prop_result | |
1275 | visit_cond_stmt (tree stmt, edge *taken_edge_p) | |
6de9cd9a | 1276 | { |
0bca51f0 | 1277 | prop_value_t val; |
750628d8 DN |
1278 | basic_block block; |
1279 | ||
1280 | block = bb_for_stmt (stmt); | |
1281 | val = evaluate_stmt (stmt); | |
1282 | ||
1283 | /* Find which edge out of the conditional block will be taken and add it | |
1284 | to the worklist. If no single edge can be determined statically, | |
1285 | return SSA_PROP_VARYING to feed all the outgoing edges to the | |
1286 | propagation engine. */ | |
0bca51f0 | 1287 | *taken_edge_p = val.value ? find_taken_edge (block, val.value) : 0; |
750628d8 DN |
1288 | if (*taken_edge_p) |
1289 | return SSA_PROP_INTERESTING; | |
1290 | else | |
1291 | return SSA_PROP_VARYING; | |
6de9cd9a DN |
1292 | } |
1293 | ||
6de9cd9a | 1294 | |
750628d8 DN |
1295 | /* Evaluate statement STMT. If the statement produces an output value and |
1296 | its evaluation changes the lattice value of its output, return | |
1297 | SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the | |
1298 | output value. | |
1299 | ||
1300 | If STMT is a conditional branch and we can determine its truth | |
1301 | value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying | |
1302 | value, return SSA_PROP_VARYING. */ | |
6de9cd9a | 1303 | |
750628d8 DN |
1304 | static enum ssa_prop_result |
1305 | ccp_visit_stmt (tree stmt, edge *taken_edge_p, tree *output_p) | |
1306 | { | |
750628d8 DN |
1307 | tree def; |
1308 | ssa_op_iter iter; | |
6de9cd9a | 1309 | |
750628d8 | 1310 | if (dump_file && (dump_flags & TDF_DETAILS)) |
6de9cd9a | 1311 | { |
0bca51f0 DN |
1312 | fprintf (dump_file, "\nVisiting statement:\n"); |
1313 | print_generic_stmt (dump_file, stmt, dump_flags); | |
750628d8 | 1314 | fprintf (dump_file, "\n"); |
6de9cd9a | 1315 | } |
6de9cd9a | 1316 | |
0bca51f0 | 1317 | if (TREE_CODE (stmt) == MODIFY_EXPR) |
6de9cd9a | 1318 | { |
750628d8 DN |
1319 | /* If the statement is an assignment that produces a single |
1320 | output value, evaluate its RHS to see if the lattice value of | |
1321 | its output has changed. */ | |
1322 | return visit_assignment (stmt, output_p); | |
6de9cd9a | 1323 | } |
750628d8 | 1324 | else if (TREE_CODE (stmt) == COND_EXPR || TREE_CODE (stmt) == SWITCH_EXPR) |
6de9cd9a | 1325 | { |
750628d8 DN |
1326 | /* If STMT is a conditional branch, see if we can determine |
1327 | which branch will be taken. */ | |
1328 | return visit_cond_stmt (stmt, taken_edge_p); | |
6de9cd9a | 1329 | } |
6de9cd9a | 1330 | |
750628d8 DN |
1331 | /* Any other kind of statement is not interesting for constant |
1332 | propagation and, therefore, not worth simulating. */ | |
750628d8 DN |
1333 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1334 | fprintf (dump_file, "No interesting values produced. Marked VARYING.\n"); | |
6de9cd9a | 1335 | |
750628d8 DN |
1336 | /* Definitions made by statements other than assignments to |
1337 | SSA_NAMEs represent unknown modifications to their outputs. | |
1338 | Mark them VARYING. */ | |
0bca51f0 DN |
1339 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) |
1340 | { | |
1341 | prop_value_t v = { VARYING, NULL_TREE, NULL_TREE }; | |
1342 | set_lattice_value (def, v); | |
1343 | } | |
6de9cd9a | 1344 | |
750628d8 DN |
1345 | return SSA_PROP_VARYING; |
1346 | } | |
6de9cd9a | 1347 | |
6de9cd9a | 1348 | |
0bca51f0 | 1349 | /* Main entry point for SSA Conditional Constant Propagation. */ |
750628d8 DN |
1350 | |
1351 | static void | |
0bca51f0 | 1352 | execute_ssa_ccp (bool store_ccp) |
750628d8 | 1353 | { |
0bca51f0 | 1354 | do_store_ccp = store_ccp; |
750628d8 DN |
1355 | ccp_initialize (); |
1356 | ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node); | |
1357 | ccp_finalize (); | |
6de9cd9a DN |
1358 | } |
1359 | ||
173b818d | 1360 | |
c2924966 | 1361 | static unsigned int |
0bca51f0 DN |
1362 | do_ssa_ccp (void) |
1363 | { | |
1364 | execute_ssa_ccp (false); | |
c2924966 | 1365 | return 0; |
0bca51f0 DN |
1366 | } |
1367 | ||
1368 | ||
173b818d | 1369 | static bool |
750628d8 | 1370 | gate_ccp (void) |
173b818d | 1371 | { |
750628d8 | 1372 | return flag_tree_ccp != 0; |
173b818d BB |
1373 | } |
1374 | ||
6de9cd9a | 1375 | |
750628d8 DN |
1376 | struct tree_opt_pass pass_ccp = |
1377 | { | |
1378 | "ccp", /* name */ | |
1379 | gate_ccp, /* gate */ | |
0bca51f0 | 1380 | do_ssa_ccp, /* execute */ |
750628d8 DN |
1381 | NULL, /* sub */ |
1382 | NULL, /* next */ | |
1383 | 0, /* static_pass_number */ | |
1384 | TV_TREE_CCP, /* tv_id */ | |
1385 | PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */ | |
1386 | 0, /* properties_provided */ | |
18cd8a03 | 1387 | PROP_smt_usage, /* properties_destroyed */ |
750628d8 | 1388 | 0, /* todo_flags_start */ |
0bca51f0 | 1389 | TODO_cleanup_cfg | TODO_dump_func | TODO_update_ssa |
750628d8 | 1390 | | TODO_ggc_collect | TODO_verify_ssa |
18cd8a03 | 1391 | | TODO_verify_stmts | TODO_update_smt_usage, /* todo_flags_finish */ |
9f8628ba | 1392 | 0 /* letter */ |
750628d8 | 1393 | }; |
6de9cd9a | 1394 | |
6de9cd9a | 1395 | |
c2924966 | 1396 | static unsigned int |
0bca51f0 DN |
1397 | do_ssa_store_ccp (void) |
1398 | { | |
1399 | /* If STORE-CCP is not enabled, we just run regular CCP. */ | |
1400 | execute_ssa_ccp (flag_tree_store_ccp != 0); | |
c2924966 | 1401 | return 0; |
0bca51f0 DN |
1402 | } |
1403 | ||
1404 | static bool | |
1405 | gate_store_ccp (void) | |
1406 | { | |
1407 | /* STORE-CCP is enabled only with -ftree-store-ccp, but when | |
1408 | -fno-tree-store-ccp is specified, we should run regular CCP. | |
1409 | That's why the pass is enabled with either flag. */ | |
1410 | return flag_tree_store_ccp != 0 || flag_tree_ccp != 0; | |
1411 | } | |
1412 | ||
1413 | ||
1414 | struct tree_opt_pass pass_store_ccp = | |
1415 | { | |
1416 | "store_ccp", /* name */ | |
1417 | gate_store_ccp, /* gate */ | |
1418 | do_ssa_store_ccp, /* execute */ | |
1419 | NULL, /* sub */ | |
1420 | NULL, /* next */ | |
1421 | 0, /* static_pass_number */ | |
1422 | TV_TREE_STORE_CCP, /* tv_id */ | |
1423 | PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */ | |
1424 | 0, /* properties_provided */ | |
18cd8a03 | 1425 | PROP_smt_usage, /* properties_destroyed */ |
0bca51f0 DN |
1426 | 0, /* todo_flags_start */ |
1427 | TODO_dump_func | TODO_update_ssa | |
1428 | | TODO_ggc_collect | TODO_verify_ssa | |
1429 | | TODO_cleanup_cfg | |
18cd8a03 | 1430 | | TODO_verify_stmts | TODO_update_smt_usage, /* todo_flags_finish */ |
0bca51f0 DN |
1431 | 0 /* letter */ |
1432 | }; | |
1433 | ||
750628d8 DN |
1434 | /* Given a constant value VAL for bitfield FIELD, and a destination |
1435 | variable VAR, return VAL appropriately widened to fit into VAR. If | |
1436 | FIELD is wider than HOST_WIDE_INT, NULL is returned. */ | |
6de9cd9a | 1437 | |
750628d8 DN |
1438 | tree |
1439 | widen_bitfield (tree val, tree field, tree var) | |
6de9cd9a | 1440 | { |
750628d8 DN |
1441 | unsigned HOST_WIDE_INT var_size, field_size; |
1442 | tree wide_val; | |
1443 | unsigned HOST_WIDE_INT mask; | |
1444 | unsigned int i; | |
6de9cd9a | 1445 | |
750628d8 DN |
1446 | /* We can only do this if the size of the type and field and VAL are |
1447 | all constants representable in HOST_WIDE_INT. */ | |
1448 | if (!host_integerp (TYPE_SIZE (TREE_TYPE (var)), 1) | |
1449 | || !host_integerp (DECL_SIZE (field), 1) | |
1450 | || !host_integerp (val, 0)) | |
1451 | return NULL_TREE; | |
6de9cd9a | 1452 | |
750628d8 DN |
1453 | var_size = tree_low_cst (TYPE_SIZE (TREE_TYPE (var)), 1); |
1454 | field_size = tree_low_cst (DECL_SIZE (field), 1); | |
6de9cd9a | 1455 | |
750628d8 DN |
1456 | /* Give up if either the bitfield or the variable are too wide. */ |
1457 | if (field_size > HOST_BITS_PER_WIDE_INT || var_size > HOST_BITS_PER_WIDE_INT) | |
1458 | return NULL_TREE; | |
6de9cd9a | 1459 | |
1e128c5f | 1460 | gcc_assert (var_size >= field_size); |
6de9cd9a | 1461 | |
750628d8 DN |
1462 | /* If the sign bit of the value is not set or the field's type is unsigned, |
1463 | just mask off the high order bits of the value. */ | |
1464 | if (DECL_UNSIGNED (field) | |
1465 | || !(tree_low_cst (val, 0) & (((HOST_WIDE_INT)1) << (field_size - 1)))) | |
1466 | { | |
1467 | /* Zero extension. Build a mask with the lower 'field_size' bits | |
1468 | set and a BIT_AND_EXPR node to clear the high order bits of | |
1469 | the value. */ | |
1470 | for (i = 0, mask = 0; i < field_size; i++) | |
1471 | mask |= ((HOST_WIDE_INT) 1) << i; | |
6de9cd9a | 1472 | |
f457cf40 JM |
1473 | wide_val = fold_build2 (BIT_AND_EXPR, TREE_TYPE (var), val, |
1474 | build_int_cst (TREE_TYPE (var), mask)); | |
6de9cd9a | 1475 | } |
750628d8 | 1476 | else |
173b818d | 1477 | { |
750628d8 DN |
1478 | /* Sign extension. Create a mask with the upper 'field_size' |
1479 | bits set and a BIT_IOR_EXPR to set the high order bits of the | |
1480 | value. */ | |
1481 | for (i = 0, mask = 0; i < (var_size - field_size); i++) | |
1482 | mask |= ((HOST_WIDE_INT) 1) << (var_size - i - 1); | |
1483 | ||
f457cf40 JM |
1484 | wide_val = fold_build2 (BIT_IOR_EXPR, TREE_TYPE (var), val, |
1485 | build_int_cst (TREE_TYPE (var), mask)); | |
173b818d | 1486 | } |
6de9cd9a | 1487 | |
f457cf40 | 1488 | return wide_val; |
6de9cd9a DN |
1489 | } |
1490 | ||
750628d8 | 1491 | |
6de9cd9a DN |
1492 | /* A subroutine of fold_stmt_r. Attempts to fold *(A+O) to A[X]. |
1493 | BASE is an array type. OFFSET is a byte displacement. ORIG_TYPE | |
9cf737f8 | 1494 | is the desired result type. */ |
6de9cd9a DN |
1495 | |
1496 | static tree | |
1497 | maybe_fold_offset_to_array_ref (tree base, tree offset, tree orig_type) | |
1498 | { | |
44de5aeb RK |
1499 | tree min_idx, idx, elt_offset = integer_zero_node; |
1500 | tree array_type, elt_type, elt_size; | |
1501 | ||
1502 | /* If BASE is an ARRAY_REF, we can pick up another offset (this time | |
1503 | measured in units of the size of elements type) from that ARRAY_REF). | |
1504 | We can't do anything if either is variable. | |
1505 | ||
1506 | The case we handle here is *(&A[N]+O). */ | |
1507 | if (TREE_CODE (base) == ARRAY_REF) | |
1508 | { | |
1509 | tree low_bound = array_ref_low_bound (base); | |
1510 | ||
1511 | elt_offset = TREE_OPERAND (base, 1); | |
1512 | if (TREE_CODE (low_bound) != INTEGER_CST | |
1513 | || TREE_CODE (elt_offset) != INTEGER_CST) | |
1514 | return NULL_TREE; | |
1515 | ||
1516 | elt_offset = int_const_binop (MINUS_EXPR, elt_offset, low_bound, 0); | |
1517 | base = TREE_OPERAND (base, 0); | |
1518 | } | |
6de9cd9a DN |
1519 | |
1520 | /* Ignore stupid user tricks of indexing non-array variables. */ | |
1521 | array_type = TREE_TYPE (base); | |
1522 | if (TREE_CODE (array_type) != ARRAY_TYPE) | |
1523 | return NULL_TREE; | |
1524 | elt_type = TREE_TYPE (array_type); | |
1525 | if (!lang_hooks.types_compatible_p (orig_type, elt_type)) | |
1526 | return NULL_TREE; | |
1527 | ||
44de5aeb RK |
1528 | /* If OFFSET and ELT_OFFSET are zero, we don't care about the size of the |
1529 | element type (so we can use the alignment if it's not constant). | |
1530 | Otherwise, compute the offset as an index by using a division. If the | |
1531 | division isn't exact, then don't do anything. */ | |
6de9cd9a | 1532 | elt_size = TYPE_SIZE_UNIT (elt_type); |
44de5aeb RK |
1533 | if (integer_zerop (offset)) |
1534 | { | |
1535 | if (TREE_CODE (elt_size) != INTEGER_CST) | |
1536 | elt_size = size_int (TYPE_ALIGN (elt_type)); | |
6de9cd9a | 1537 | |
44de5aeb RK |
1538 | idx = integer_zero_node; |
1539 | } | |
1540 | else | |
1541 | { | |
1542 | unsigned HOST_WIDE_INT lquo, lrem; | |
1543 | HOST_WIDE_INT hquo, hrem; | |
1544 | ||
1545 | if (TREE_CODE (elt_size) != INTEGER_CST | |
1546 | || div_and_round_double (TRUNC_DIV_EXPR, 1, | |
1547 | TREE_INT_CST_LOW (offset), | |
1548 | TREE_INT_CST_HIGH (offset), | |
1549 | TREE_INT_CST_LOW (elt_size), | |
1550 | TREE_INT_CST_HIGH (elt_size), | |
1551 | &lquo, &hquo, &lrem, &hrem) | |
1552 | || lrem || hrem) | |
1553 | return NULL_TREE; | |
6de9cd9a | 1554 | |
7d60be94 | 1555 | idx = build_int_cst_wide (NULL_TREE, lquo, hquo); |
44de5aeb RK |
1556 | } |
1557 | ||
1558 | /* Assume the low bound is zero. If there is a domain type, get the | |
1559 | low bound, if any, convert the index into that type, and add the | |
1560 | low bound. */ | |
1561 | min_idx = integer_zero_node; | |
1562 | if (TYPE_DOMAIN (array_type)) | |
6de9cd9a | 1563 | { |
44de5aeb RK |
1564 | if (TYPE_MIN_VALUE (TYPE_DOMAIN (array_type))) |
1565 | min_idx = TYPE_MIN_VALUE (TYPE_DOMAIN (array_type)); | |
1566 | else | |
1567 | min_idx = fold_convert (TYPE_DOMAIN (array_type), min_idx); | |
1568 | ||
1569 | if (TREE_CODE (min_idx) != INTEGER_CST) | |
1570 | return NULL_TREE; | |
1571 | ||
1572 | idx = fold_convert (TYPE_DOMAIN (array_type), idx); | |
1573 | elt_offset = fold_convert (TYPE_DOMAIN (array_type), elt_offset); | |
6de9cd9a DN |
1574 | } |
1575 | ||
44de5aeb RK |
1576 | if (!integer_zerop (min_idx)) |
1577 | idx = int_const_binop (PLUS_EXPR, idx, min_idx, 0); | |
1578 | if (!integer_zerop (elt_offset)) | |
1579 | idx = int_const_binop (PLUS_EXPR, idx, elt_offset, 0); | |
1580 | ||
b4257cfc RG |
1581 | return build4 (ARRAY_REF, orig_type, base, idx, min_idx, |
1582 | size_int (tree_low_cst (elt_size, 1) | |
1583 | / (TYPE_ALIGN_UNIT (elt_type)))); | |
6de9cd9a DN |
1584 | } |
1585 | ||
750628d8 | 1586 | |
6de9cd9a DN |
1587 | /* A subroutine of fold_stmt_r. Attempts to fold *(S+O) to S.X. |
1588 | BASE is a record type. OFFSET is a byte displacement. ORIG_TYPE | |
1589 | is the desired result type. */ | |
1590 | /* ??? This doesn't handle class inheritance. */ | |
1591 | ||
1592 | static tree | |
1593 | maybe_fold_offset_to_component_ref (tree record_type, tree base, tree offset, | |
1594 | tree orig_type, bool base_is_ptr) | |
1595 | { | |
f34fa464 | 1596 | tree f, t, field_type, tail_array_field, field_offset; |
6de9cd9a DN |
1597 | |
1598 | if (TREE_CODE (record_type) != RECORD_TYPE | |
1599 | && TREE_CODE (record_type) != UNION_TYPE | |
1600 | && TREE_CODE (record_type) != QUAL_UNION_TYPE) | |
1601 | return NULL_TREE; | |
1602 | ||
1603 | /* Short-circuit silly cases. */ | |
1604 | if (lang_hooks.types_compatible_p (record_type, orig_type)) | |
1605 | return NULL_TREE; | |
1606 | ||
1607 | tail_array_field = NULL_TREE; | |
1608 | for (f = TYPE_FIELDS (record_type); f ; f = TREE_CHAIN (f)) | |
1609 | { | |
1610 | int cmp; | |
1611 | ||
1612 | if (TREE_CODE (f) != FIELD_DECL) | |
1613 | continue; | |
1614 | if (DECL_BIT_FIELD (f)) | |
1615 | continue; | |
f34fa464 ZD |
1616 | |
1617 | field_offset = byte_position (f); | |
1618 | if (TREE_CODE (field_offset) != INTEGER_CST) | |
6de9cd9a DN |
1619 | continue; |
1620 | ||
1621 | /* ??? Java creates "interesting" fields for representing base classes. | |
1622 | They have no name, and have no context. With no context, we get into | |
1623 | trouble with nonoverlapping_component_refs_p. Skip them. */ | |
1624 | if (!DECL_FIELD_CONTEXT (f)) | |
1625 | continue; | |
1626 | ||
1627 | /* The previous array field isn't at the end. */ | |
1628 | tail_array_field = NULL_TREE; | |
1629 | ||
1630 | /* Check to see if this offset overlaps with the field. */ | |
f34fa464 | 1631 | cmp = tree_int_cst_compare (field_offset, offset); |
6de9cd9a DN |
1632 | if (cmp > 0) |
1633 | continue; | |
1634 | ||
1635 | field_type = TREE_TYPE (f); | |
6de9cd9a DN |
1636 | |
1637 | /* Here we exactly match the offset being checked. If the types match, | |
1638 | then we can return that field. */ | |
53dba802 ZD |
1639 | if (cmp == 0 |
1640 | && lang_hooks.types_compatible_p (orig_type, field_type)) | |
6de9cd9a DN |
1641 | { |
1642 | if (base_is_ptr) | |
1643 | base = build1 (INDIRECT_REF, record_type, base); | |
b4257cfc | 1644 | t = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE); |
6de9cd9a DN |
1645 | return t; |
1646 | } | |
53dba802 ZD |
1647 | |
1648 | /* Don't care about offsets into the middle of scalars. */ | |
1649 | if (!AGGREGATE_TYPE_P (field_type)) | |
1650 | continue; | |
6de9cd9a | 1651 | |
53dba802 ZD |
1652 | /* Check for array at the end of the struct. This is often |
1653 | used as for flexible array members. We should be able to | |
1654 | turn this into an array access anyway. */ | |
1655 | if (TREE_CODE (field_type) == ARRAY_TYPE) | |
1656 | tail_array_field = f; | |
1657 | ||
1658 | /* Check the end of the field against the offset. */ | |
1659 | if (!DECL_SIZE_UNIT (f) | |
1660 | || TREE_CODE (DECL_SIZE_UNIT (f)) != INTEGER_CST) | |
1661 | continue; | |
1662 | t = int_const_binop (MINUS_EXPR, offset, field_offset, 1); | |
1663 | if (!tree_int_cst_lt (t, DECL_SIZE_UNIT (f))) | |
1664 | continue; | |
6de9cd9a | 1665 | |
53dba802 ZD |
1666 | /* If we matched, then set offset to the displacement into |
1667 | this field. */ | |
1668 | offset = t; | |
6de9cd9a DN |
1669 | goto found; |
1670 | } | |
1671 | ||
1672 | if (!tail_array_field) | |
1673 | return NULL_TREE; | |
1674 | ||
1675 | f = tail_array_field; | |
1676 | field_type = TREE_TYPE (f); | |
53dba802 | 1677 | offset = int_const_binop (MINUS_EXPR, offset, byte_position (f), 1); |
6de9cd9a DN |
1678 | |
1679 | found: | |
1680 | /* If we get here, we've got an aggregate field, and a possibly | |
1ea7e6ad | 1681 | nonzero offset into them. Recurse and hope for a valid match. */ |
6de9cd9a DN |
1682 | if (base_is_ptr) |
1683 | base = build1 (INDIRECT_REF, record_type, base); | |
b4257cfc | 1684 | base = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE); |
6de9cd9a DN |
1685 | |
1686 | t = maybe_fold_offset_to_array_ref (base, offset, orig_type); | |
1687 | if (t) | |
1688 | return t; | |
1689 | return maybe_fold_offset_to_component_ref (field_type, base, offset, | |
1690 | orig_type, false); | |
1691 | } | |
1692 | ||
750628d8 | 1693 | |
6de9cd9a DN |
1694 | /* A subroutine of fold_stmt_r. Attempt to simplify *(BASE+OFFSET). |
1695 | Return the simplified expression, or NULL if nothing could be done. */ | |
1696 | ||
1697 | static tree | |
1698 | maybe_fold_stmt_indirect (tree expr, tree base, tree offset) | |
1699 | { | |
1700 | tree t; | |
1701 | ||
1702 | /* We may well have constructed a double-nested PLUS_EXPR via multiple | |
1703 | substitutions. Fold that down to one. Remove NON_LVALUE_EXPRs that | |
1704 | are sometimes added. */ | |
1705 | base = fold (base); | |
ff7c8597 | 1706 | STRIP_TYPE_NOPS (base); |
6de9cd9a DN |
1707 | TREE_OPERAND (expr, 0) = base; |
1708 | ||
1709 | /* One possibility is that the address reduces to a string constant. */ | |
1710 | t = fold_read_from_constant_string (expr); | |
1711 | if (t) | |
1712 | return t; | |
1713 | ||
1714 | /* Add in any offset from a PLUS_EXPR. */ | |
1715 | if (TREE_CODE (base) == PLUS_EXPR) | |
1716 | { | |
1717 | tree offset2; | |
1718 | ||
1719 | offset2 = TREE_OPERAND (base, 1); | |
1720 | if (TREE_CODE (offset2) != INTEGER_CST) | |
1721 | return NULL_TREE; | |
1722 | base = TREE_OPERAND (base, 0); | |
1723 | ||
1724 | offset = int_const_binop (PLUS_EXPR, offset, offset2, 1); | |
1725 | } | |
1726 | ||
1727 | if (TREE_CODE (base) == ADDR_EXPR) | |
1728 | { | |
1729 | /* Strip the ADDR_EXPR. */ | |
1730 | base = TREE_OPERAND (base, 0); | |
1731 | ||
0534fa56 RH |
1732 | /* Fold away CONST_DECL to its value, if the type is scalar. */ |
1733 | if (TREE_CODE (base) == CONST_DECL | |
688e936d | 1734 | && ccp_decl_initial_min_invariant (DECL_INITIAL (base))) |
0534fa56 RH |
1735 | return DECL_INITIAL (base); |
1736 | ||
6de9cd9a DN |
1737 | /* Try folding *(&B+O) to B[X]. */ |
1738 | t = maybe_fold_offset_to_array_ref (base, offset, TREE_TYPE (expr)); | |
1739 | if (t) | |
1740 | return t; | |
1741 | ||
1742 | /* Try folding *(&B+O) to B.X. */ | |
1743 | t = maybe_fold_offset_to_component_ref (TREE_TYPE (base), base, offset, | |
1744 | TREE_TYPE (expr), false); | |
1745 | if (t) | |
1746 | return t; | |
1747 | ||
44de5aeb RK |
1748 | /* Fold *&B to B. We can only do this if EXPR is the same type |
1749 | as BASE. We can't do this if EXPR is the element type of an array | |
1750 | and BASE is the array. */ | |
1751 | if (integer_zerop (offset) | |
1752 | && lang_hooks.types_compatible_p (TREE_TYPE (base), | |
1753 | TREE_TYPE (expr))) | |
6de9cd9a DN |
1754 | return base; |
1755 | } | |
1756 | else | |
1757 | { | |
1758 | /* We can get here for out-of-range string constant accesses, | |
1759 | such as "_"[3]. Bail out of the entire substitution search | |
1760 | and arrange for the entire statement to be replaced by a | |
aabcd309 | 1761 | call to __builtin_trap. In all likelihood this will all be |
6de9cd9a DN |
1762 | constant-folded away, but in the meantime we can't leave with |
1763 | something that get_expr_operands can't understand. */ | |
1764 | ||
1765 | t = base; | |
1766 | STRIP_NOPS (t); | |
1767 | if (TREE_CODE (t) == ADDR_EXPR | |
1768 | && TREE_CODE (TREE_OPERAND (t, 0)) == STRING_CST) | |
1769 | { | |
1770 | /* FIXME: Except that this causes problems elsewhere with dead | |
0e61db61 | 1771 | code not being deleted, and we die in the rtl expanders |
6de9cd9a DN |
1772 | because we failed to remove some ssa_name. In the meantime, |
1773 | just return zero. */ | |
1774 | /* FIXME2: This condition should be signaled by | |
1775 | fold_read_from_constant_string directly, rather than | |
1776 | re-checking for it here. */ | |
1777 | return integer_zero_node; | |
1778 | } | |
1779 | ||
1780 | /* Try folding *(B+O) to B->X. Still an improvement. */ | |
1781 | if (POINTER_TYPE_P (TREE_TYPE (base))) | |
1782 | { | |
1783 | t = maybe_fold_offset_to_component_ref (TREE_TYPE (TREE_TYPE (base)), | |
1784 | base, offset, | |
1785 | TREE_TYPE (expr), true); | |
1786 | if (t) | |
1787 | return t; | |
1788 | } | |
1789 | } | |
1790 | ||
1791 | /* Otherwise we had an offset that we could not simplify. */ | |
1792 | return NULL_TREE; | |
1793 | } | |
1794 | ||
750628d8 | 1795 | |
6de9cd9a DN |
1796 | /* A subroutine of fold_stmt_r. EXPR is a PLUS_EXPR. |
1797 | ||
1798 | A quaint feature extant in our address arithmetic is that there | |
1799 | can be hidden type changes here. The type of the result need | |
1800 | not be the same as the type of the input pointer. | |
1801 | ||
1802 | What we're after here is an expression of the form | |
1803 | (T *)(&array + const) | |
1804 | where the cast doesn't actually exist, but is implicit in the | |
1805 | type of the PLUS_EXPR. We'd like to turn this into | |
1806 | &array[x] | |
1807 | which may be able to propagate further. */ | |
1808 | ||
1809 | static tree | |
1810 | maybe_fold_stmt_addition (tree expr) | |
1811 | { | |
1812 | tree op0 = TREE_OPERAND (expr, 0); | |
1813 | tree op1 = TREE_OPERAND (expr, 1); | |
1814 | tree ptr_type = TREE_TYPE (expr); | |
1815 | tree ptd_type; | |
1816 | tree t; | |
1817 | bool subtract = (TREE_CODE (expr) == MINUS_EXPR); | |
1818 | ||
1819 | /* We're only interested in pointer arithmetic. */ | |
1820 | if (!POINTER_TYPE_P (ptr_type)) | |
1821 | return NULL_TREE; | |
1822 | /* Canonicalize the integral operand to op1. */ | |
1823 | if (INTEGRAL_TYPE_P (TREE_TYPE (op0))) | |
1824 | { | |
1825 | if (subtract) | |
1826 | return NULL_TREE; | |
1827 | t = op0, op0 = op1, op1 = t; | |
1828 | } | |
1829 | /* It had better be a constant. */ | |
1830 | if (TREE_CODE (op1) != INTEGER_CST) | |
1831 | return NULL_TREE; | |
1832 | /* The first operand should be an ADDR_EXPR. */ | |
1833 | if (TREE_CODE (op0) != ADDR_EXPR) | |
1834 | return NULL_TREE; | |
1835 | op0 = TREE_OPERAND (op0, 0); | |
1836 | ||
1837 | /* If the first operand is an ARRAY_REF, expand it so that we can fold | |
1838 | the offset into it. */ | |
1839 | while (TREE_CODE (op0) == ARRAY_REF) | |
1840 | { | |
1841 | tree array_obj = TREE_OPERAND (op0, 0); | |
1842 | tree array_idx = TREE_OPERAND (op0, 1); | |
1843 | tree elt_type = TREE_TYPE (op0); | |
1844 | tree elt_size = TYPE_SIZE_UNIT (elt_type); | |
1845 | tree min_idx; | |
1846 | ||
1847 | if (TREE_CODE (array_idx) != INTEGER_CST) | |
1848 | break; | |
1849 | if (TREE_CODE (elt_size) != INTEGER_CST) | |
1850 | break; | |
1851 | ||
1852 | /* Un-bias the index by the min index of the array type. */ | |
1853 | min_idx = TYPE_DOMAIN (TREE_TYPE (array_obj)); | |
1854 | if (min_idx) | |
1855 | { | |
1856 | min_idx = TYPE_MIN_VALUE (min_idx); | |
1857 | if (min_idx) | |
1858 | { | |
44de5aeb RK |
1859 | if (TREE_CODE (min_idx) != INTEGER_CST) |
1860 | break; | |
1861 | ||
b6f65e3c | 1862 | array_idx = fold_convert (TREE_TYPE (min_idx), array_idx); |
6de9cd9a DN |
1863 | if (!integer_zerop (min_idx)) |
1864 | array_idx = int_const_binop (MINUS_EXPR, array_idx, | |
1865 | min_idx, 0); | |
1866 | } | |
1867 | } | |
1868 | ||
1869 | /* Convert the index to a byte offset. */ | |
b6f65e3c | 1870 | array_idx = fold_convert (sizetype, array_idx); |
6de9cd9a DN |
1871 | array_idx = int_const_binop (MULT_EXPR, array_idx, elt_size, 0); |
1872 | ||
1873 | /* Update the operands for the next round, or for folding. */ | |
1874 | /* If we're manipulating unsigned types, then folding into negative | |
1875 | values can produce incorrect results. Particularly if the type | |
1876 | is smaller than the width of the pointer. */ | |
1877 | if (subtract | |
1878 | && TYPE_UNSIGNED (TREE_TYPE (op1)) | |
1879 | && tree_int_cst_lt (array_idx, op1)) | |
1880 | return NULL; | |
1881 | op1 = int_const_binop (subtract ? MINUS_EXPR : PLUS_EXPR, | |
1882 | array_idx, op1, 0); | |
1883 | subtract = false; | |
1884 | op0 = array_obj; | |
1885 | } | |
1886 | ||
1887 | /* If we weren't able to fold the subtraction into another array reference, | |
1888 | canonicalize the integer for passing to the array and component ref | |
1889 | simplification functions. */ | |
1890 | if (subtract) | |
1891 | { | |
1892 | if (TYPE_UNSIGNED (TREE_TYPE (op1))) | |
1893 | return NULL; | |
0dd4b47b | 1894 | op1 = fold_unary (NEGATE_EXPR, TREE_TYPE (op1), op1); |
6de9cd9a | 1895 | /* ??? In theory fold should always produce another integer. */ |
0dd4b47b | 1896 | if (op1 == NULL || TREE_CODE (op1) != INTEGER_CST) |
6de9cd9a DN |
1897 | return NULL; |
1898 | } | |
1899 | ||
1900 | ptd_type = TREE_TYPE (ptr_type); | |
1901 | ||
1902 | /* At which point we can try some of the same things as for indirects. */ | |
1903 | t = maybe_fold_offset_to_array_ref (op0, op1, ptd_type); | |
1904 | if (!t) | |
1905 | t = maybe_fold_offset_to_component_ref (TREE_TYPE (op0), op0, op1, | |
1906 | ptd_type, false); | |
1907 | if (t) | |
1908 | t = build1 (ADDR_EXPR, ptr_type, t); | |
1909 | ||
1910 | return t; | |
1911 | } | |
1912 | ||
622f91ba JL |
1913 | /* For passing state through walk_tree into fold_stmt_r and its |
1914 | children. */ | |
1915 | ||
1916 | struct fold_stmt_r_data | |
1917 | { | |
1918 | bool *changed_p; | |
1919 | bool *inside_addr_expr_p; | |
1920 | }; | |
1921 | ||
6de9cd9a DN |
1922 | /* Subroutine of fold_stmt called via walk_tree. We perform several |
1923 | simplifications of EXPR_P, mostly having to do with pointer arithmetic. */ | |
1924 | ||
1925 | static tree | |
1926 | fold_stmt_r (tree *expr_p, int *walk_subtrees, void *data) | |
1927 | { | |
858904db | 1928 | struct fold_stmt_r_data *fold_stmt_r_data = (struct fold_stmt_r_data *) data; |
622f91ba JL |
1929 | bool *inside_addr_expr_p = fold_stmt_r_data->inside_addr_expr_p; |
1930 | bool *changed_p = fold_stmt_r_data->changed_p; | |
6de9cd9a DN |
1931 | tree expr = *expr_p, t; |
1932 | ||
1933 | /* ??? It'd be nice if walk_tree had a pre-order option. */ | |
1934 | switch (TREE_CODE (expr)) | |
1935 | { | |
1936 | case INDIRECT_REF: | |
1937 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
1938 | if (t) | |
1939 | return t; | |
1940 | *walk_subtrees = 0; | |
1941 | ||
1942 | t = maybe_fold_stmt_indirect (expr, TREE_OPERAND (expr, 0), | |
1943 | integer_zero_node); | |
1944 | break; | |
1945 | ||
622f91ba | 1946 | /* ??? Could handle more ARRAY_REFs here, as a variant of INDIRECT_REF. |
6de9cd9a DN |
1947 | We'd only want to bother decomposing an existing ARRAY_REF if |
1948 | the base array is found to have another offset contained within. | |
1949 | Otherwise we'd be wasting time. */ | |
622f91ba JL |
1950 | case ARRAY_REF: |
1951 | /* If we are not processing expressions found within an | |
1952 | ADDR_EXPR, then we can fold constant array references. */ | |
1953 | if (!*inside_addr_expr_p) | |
1954 | t = fold_read_from_constant_string (expr); | |
1955 | else | |
1956 | t = NULL; | |
1957 | break; | |
6de9cd9a DN |
1958 | |
1959 | case ADDR_EXPR: | |
622f91ba | 1960 | *inside_addr_expr_p = true; |
6de9cd9a | 1961 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); |
622f91ba | 1962 | *inside_addr_expr_p = false; |
6de9cd9a DN |
1963 | if (t) |
1964 | return t; | |
1965 | *walk_subtrees = 0; | |
1966 | ||
1967 | /* Set TREE_INVARIANT properly so that the value is properly | |
1968 | considered constant, and so gets propagated as expected. */ | |
1969 | if (*changed_p) | |
127203ac | 1970 | recompute_tree_invariant_for_addr_expr (expr); |
6de9cd9a DN |
1971 | return NULL_TREE; |
1972 | ||
1973 | case PLUS_EXPR: | |
1974 | case MINUS_EXPR: | |
1975 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
1976 | if (t) | |
1977 | return t; | |
1978 | t = walk_tree (&TREE_OPERAND (expr, 1), fold_stmt_r, data, NULL); | |
1979 | if (t) | |
1980 | return t; | |
1981 | *walk_subtrees = 0; | |
1982 | ||
1983 | t = maybe_fold_stmt_addition (expr); | |
1984 | break; | |
1985 | ||
1986 | case COMPONENT_REF: | |
1987 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
1988 | if (t) | |
1989 | return t; | |
1990 | *walk_subtrees = 0; | |
1991 | ||
fa27426e RH |
1992 | /* Make sure the FIELD_DECL is actually a field in the type on the lhs. |
1993 | We've already checked that the records are compatible, so we should | |
1994 | come up with a set of compatible fields. */ | |
1995 | { | |
1996 | tree expr_record = TREE_TYPE (TREE_OPERAND (expr, 0)); | |
1997 | tree expr_field = TREE_OPERAND (expr, 1); | |
1998 | ||
1999 | if (DECL_FIELD_CONTEXT (expr_field) != TYPE_MAIN_VARIANT (expr_record)) | |
2000 | { | |
2001 | expr_field = find_compatible_field (expr_record, expr_field); | |
2002 | TREE_OPERAND (expr, 1) = expr_field; | |
2003 | } | |
2004 | } | |
6de9cd9a DN |
2005 | break; |
2006 | ||
ac182688 ZD |
2007 | case TARGET_MEM_REF: |
2008 | t = maybe_fold_tmr (expr); | |
2009 | break; | |
2010 | ||
f393e7f5 RG |
2011 | case COND_EXPR: |
2012 | if (COMPARISON_CLASS_P (TREE_OPERAND (expr, 0))) | |
2013 | { | |
2014 | tree op0 = TREE_OPERAND (expr, 0); | |
2015 | tree tem = fold_binary (TREE_CODE (op0), TREE_TYPE (op0), | |
5cdc4a26 RS |
2016 | TREE_OPERAND (op0, 0), |
2017 | TREE_OPERAND (op0, 1)); | |
2018 | if (tem && set_rhs (expr_p, tem)) | |
2019 | { | |
2020 | t = *expr_p; | |
2021 | break; | |
2022 | } | |
f393e7f5 | 2023 | } |
5cdc4a26 | 2024 | return NULL_TREE; |
f393e7f5 | 2025 | |
6de9cd9a DN |
2026 | default: |
2027 | return NULL_TREE; | |
2028 | } | |
2029 | ||
2030 | if (t) | |
2031 | { | |
2032 | *expr_p = t; | |
2033 | *changed_p = true; | |
2034 | } | |
2035 | ||
2036 | return NULL_TREE; | |
2037 | } | |
2038 | ||
6de9cd9a | 2039 | |
10a0d495 JJ |
2040 | /* Return the string length, maximum string length or maximum value of |
2041 | ARG in LENGTH. | |
2042 | If ARG is an SSA name variable, follow its use-def chains. If LENGTH | |
2043 | is not NULL and, for TYPE == 0, its value is not equal to the length | |
2044 | we determine or if we are unable to determine the length or value, | |
2045 | return false. VISITED is a bitmap of visited variables. | |
2046 | TYPE is 0 if string length should be returned, 1 for maximum string | |
2047 | length and 2 for maximum value ARG can have. */ | |
6de9cd9a | 2048 | |
06a9b53f | 2049 | static bool |
10a0d495 | 2050 | get_maxval_strlen (tree arg, tree *length, bitmap visited, int type) |
6de9cd9a | 2051 | { |
750628d8 DN |
2052 | tree var, def_stmt, val; |
2053 | ||
2054 | if (TREE_CODE (arg) != SSA_NAME) | |
06a9b53f | 2055 | { |
10a0d495 JJ |
2056 | if (type == 2) |
2057 | { | |
2058 | val = arg; | |
2059 | if (TREE_CODE (val) != INTEGER_CST | |
2060 | || tree_int_cst_sgn (val) < 0) | |
2061 | return false; | |
2062 | } | |
2063 | else | |
2064 | val = c_strlen (arg, 1); | |
750628d8 | 2065 | if (!val) |
06a9b53f | 2066 | return false; |
cd709752 | 2067 | |
10a0d495 JJ |
2068 | if (*length) |
2069 | { | |
2070 | if (type > 0) | |
2071 | { | |
2072 | if (TREE_CODE (*length) != INTEGER_CST | |
2073 | || TREE_CODE (val) != INTEGER_CST) | |
2074 | return false; | |
2075 | ||
2076 | if (tree_int_cst_lt (*length, val)) | |
2077 | *length = val; | |
2078 | return true; | |
2079 | } | |
2080 | else if (simple_cst_equal (val, *length) != 1) | |
2081 | return false; | |
2082 | } | |
6de9cd9a | 2083 | |
750628d8 DN |
2084 | *length = val; |
2085 | return true; | |
6de9cd9a | 2086 | } |
06a9b53f | 2087 | |
750628d8 DN |
2088 | /* If we were already here, break the infinite cycle. */ |
2089 | if (bitmap_bit_p (visited, SSA_NAME_VERSION (arg))) | |
2090 | return true; | |
2091 | bitmap_set_bit (visited, SSA_NAME_VERSION (arg)); | |
2092 | ||
2093 | var = arg; | |
2094 | def_stmt = SSA_NAME_DEF_STMT (var); | |
6de9cd9a | 2095 | |
750628d8 DN |
2096 | switch (TREE_CODE (def_stmt)) |
2097 | { | |
2098 | case MODIFY_EXPR: | |
2099 | { | |
10a0d495 JJ |
2100 | tree rhs; |
2101 | ||
750628d8 DN |
2102 | /* The RHS of the statement defining VAR must either have a |
2103 | constant length or come from another SSA_NAME with a constant | |
2104 | length. */ | |
2105 | rhs = TREE_OPERAND (def_stmt, 1); | |
2106 | STRIP_NOPS (rhs); | |
10a0d495 | 2107 | return get_maxval_strlen (rhs, length, visited, type); |
750628d8 | 2108 | } |
6de9cd9a | 2109 | |
750628d8 DN |
2110 | case PHI_NODE: |
2111 | { | |
2112 | /* All the arguments of the PHI node must have the same constant | |
2113 | length. */ | |
2114 | int i; | |
6de9cd9a | 2115 | |
750628d8 DN |
2116 | for (i = 0; i < PHI_NUM_ARGS (def_stmt); i++) |
2117 | { | |
2118 | tree arg = PHI_ARG_DEF (def_stmt, i); | |
6de9cd9a | 2119 | |
750628d8 DN |
2120 | /* If this PHI has itself as an argument, we cannot |
2121 | determine the string length of this argument. However, | |
2122 | if we can find a constant string length for the other | |
2123 | PHI args then we can still be sure that this is a | |
2124 | constant string length. So be optimistic and just | |
2125 | continue with the next argument. */ | |
2126 | if (arg == PHI_RESULT (def_stmt)) | |
2127 | continue; | |
6de9cd9a | 2128 | |
10a0d495 | 2129 | if (!get_maxval_strlen (arg, length, visited, type)) |
750628d8 DN |
2130 | return false; |
2131 | } | |
6de9cd9a | 2132 | |
750628d8 | 2133 | return true; |
173b818d | 2134 | } |
6de9cd9a | 2135 | |
750628d8 DN |
2136 | default: |
2137 | break; | |
6de9cd9a DN |
2138 | } |
2139 | ||
750628d8 DN |
2140 | |
2141 | return false; | |
6de9cd9a DN |
2142 | } |
2143 | ||
2144 | ||
2145 | /* Fold builtin call FN in statement STMT. If it cannot be folded into a | |
2146 | constant, return NULL_TREE. Otherwise, return its constant value. */ | |
2147 | ||
2148 | static tree | |
2149 | ccp_fold_builtin (tree stmt, tree fn) | |
2150 | { | |
10a0d495 | 2151 | tree result, val[3]; |
a32e70c3 | 2152 | tree callee, arglist, a; |
10a0d495 | 2153 | int arg_mask, i, type; |
a32e70c3 RS |
2154 | bitmap visited; |
2155 | bool ignore; | |
6de9cd9a | 2156 | |
a32e70c3 | 2157 | ignore = TREE_CODE (stmt) != MODIFY_EXPR; |
6de9cd9a DN |
2158 | |
2159 | /* First try the generic builtin folder. If that succeeds, return the | |
2160 | result directly. */ | |
49d1af89 KH |
2161 | callee = get_callee_fndecl (fn); |
2162 | arglist = TREE_OPERAND (fn, 1); | |
2163 | result = fold_builtin (callee, arglist, ignore); | |
6de9cd9a | 2164 | if (result) |
10a0d495 JJ |
2165 | { |
2166 | if (ignore) | |
2167 | STRIP_NOPS (result); | |
2168 | return result; | |
2169 | } | |
a32e70c3 RS |
2170 | |
2171 | /* Ignore MD builtins. */ | |
a32e70c3 RS |
2172 | if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_MD) |
2173 | return NULL_TREE; | |
6de9cd9a DN |
2174 | |
2175 | /* If the builtin could not be folded, and it has no argument list, | |
2176 | we're done. */ | |
2177 | if (!arglist) | |
2178 | return NULL_TREE; | |
2179 | ||
2180 | /* Limit the work only for builtins we know how to simplify. */ | |
2181 | switch (DECL_FUNCTION_CODE (callee)) | |
2182 | { | |
2183 | case BUILT_IN_STRLEN: | |
2184 | case BUILT_IN_FPUTS: | |
2185 | case BUILT_IN_FPUTS_UNLOCKED: | |
10a0d495 JJ |
2186 | arg_mask = 1; |
2187 | type = 0; | |
6de9cd9a DN |
2188 | break; |
2189 | case BUILT_IN_STRCPY: | |
2190 | case BUILT_IN_STRNCPY: | |
10a0d495 JJ |
2191 | arg_mask = 2; |
2192 | type = 0; | |
2193 | break; | |
2194 | case BUILT_IN_MEMCPY_CHK: | |
2195 | case BUILT_IN_MEMPCPY_CHK: | |
2196 | case BUILT_IN_MEMMOVE_CHK: | |
2197 | case BUILT_IN_MEMSET_CHK: | |
2198 | case BUILT_IN_STRNCPY_CHK: | |
2199 | arg_mask = 4; | |
2200 | type = 2; | |
2201 | break; | |
2202 | case BUILT_IN_STRCPY_CHK: | |
2203 | case BUILT_IN_STPCPY_CHK: | |
2204 | arg_mask = 2; | |
2205 | type = 1; | |
2206 | break; | |
2207 | case BUILT_IN_SNPRINTF_CHK: | |
2208 | case BUILT_IN_VSNPRINTF_CHK: | |
2209 | arg_mask = 2; | |
2210 | type = 2; | |
6de9cd9a DN |
2211 | break; |
2212 | default: | |
2213 | return NULL_TREE; | |
2214 | } | |
2215 | ||
2216 | /* Try to use the dataflow information gathered by the CCP process. */ | |
8bdbfff5 | 2217 | visited = BITMAP_ALLOC (NULL); |
6de9cd9a | 2218 | |
10a0d495 | 2219 | memset (val, 0, sizeof (val)); |
6de9cd9a | 2220 | for (i = 0, a = arglist; |
10a0d495 JJ |
2221 | arg_mask; |
2222 | i++, arg_mask >>= 1, a = TREE_CHAIN (a)) | |
2223 | if (arg_mask & 1) | |
6de9cd9a DN |
2224 | { |
2225 | bitmap_clear (visited); | |
10a0d495 JJ |
2226 | if (!get_maxval_strlen (TREE_VALUE (a), &val[i], visited, type)) |
2227 | val[i] = NULL_TREE; | |
6de9cd9a DN |
2228 | } |
2229 | ||
8bdbfff5 | 2230 | BITMAP_FREE (visited); |
6de9cd9a | 2231 | |
a32e70c3 | 2232 | result = NULL_TREE; |
6de9cd9a DN |
2233 | switch (DECL_FUNCTION_CODE (callee)) |
2234 | { | |
2235 | case BUILT_IN_STRLEN: | |
10a0d495 | 2236 | if (val[0]) |
6de9cd9a | 2237 | { |
10a0d495 | 2238 | tree new = fold_convert (TREE_TYPE (fn), val[0]); |
6de9cd9a DN |
2239 | |
2240 | /* If the result is not a valid gimple value, or not a cast | |
2241 | of a valid gimple value, then we can not use the result. */ | |
2242 | if (is_gimple_val (new) | |
2243 | || (is_gimple_cast (new) | |
2244 | && is_gimple_val (TREE_OPERAND (new, 0)))) | |
2245 | return new; | |
6de9cd9a | 2246 | } |
a32e70c3 RS |
2247 | break; |
2248 | ||
6de9cd9a | 2249 | case BUILT_IN_STRCPY: |
10a0d495 JJ |
2250 | if (val[1] && is_gimple_val (val[1])) |
2251 | result = fold_builtin_strcpy (callee, arglist, val[1]); | |
a32e70c3 RS |
2252 | break; |
2253 | ||
6de9cd9a | 2254 | case BUILT_IN_STRNCPY: |
10a0d495 JJ |
2255 | if (val[1] && is_gimple_val (val[1])) |
2256 | result = fold_builtin_strncpy (callee, arglist, val[1]); | |
a32e70c3 RS |
2257 | break; |
2258 | ||
6de9cd9a | 2259 | case BUILT_IN_FPUTS: |
a32e70c3 RS |
2260 | result = fold_builtin_fputs (arglist, |
2261 | TREE_CODE (stmt) != MODIFY_EXPR, 0, | |
10a0d495 | 2262 | val[0]); |
a32e70c3 RS |
2263 | break; |
2264 | ||
6de9cd9a | 2265 | case BUILT_IN_FPUTS_UNLOCKED: |
a32e70c3 RS |
2266 | result = fold_builtin_fputs (arglist, |
2267 | TREE_CODE (stmt) != MODIFY_EXPR, 1, | |
10a0d495 JJ |
2268 | val[0]); |
2269 | break; | |
2270 | ||
2271 | case BUILT_IN_MEMCPY_CHK: | |
2272 | case BUILT_IN_MEMPCPY_CHK: | |
2273 | case BUILT_IN_MEMMOVE_CHK: | |
2274 | case BUILT_IN_MEMSET_CHK: | |
2275 | if (val[2] && is_gimple_val (val[2])) | |
2276 | result = fold_builtin_memory_chk (callee, arglist, val[2], ignore, | |
2277 | DECL_FUNCTION_CODE (callee)); | |
2278 | break; | |
2279 | ||
2280 | case BUILT_IN_STRCPY_CHK: | |
2281 | case BUILT_IN_STPCPY_CHK: | |
2282 | if (val[1] && is_gimple_val (val[1])) | |
2283 | result = fold_builtin_stxcpy_chk (callee, arglist, val[1], ignore, | |
2284 | DECL_FUNCTION_CODE (callee)); | |
2285 | break; | |
2286 | ||
2287 | case BUILT_IN_STRNCPY_CHK: | |
2288 | if (val[2] && is_gimple_val (val[2])) | |
2289 | result = fold_builtin_strncpy_chk (arglist, val[2]); | |
2290 | break; | |
2291 | ||
2292 | case BUILT_IN_SNPRINTF_CHK: | |
2293 | case BUILT_IN_VSNPRINTF_CHK: | |
2294 | if (val[1] && is_gimple_val (val[1])) | |
2295 | result = fold_builtin_snprintf_chk (arglist, val[1], | |
2296 | DECL_FUNCTION_CODE (callee)); | |
a32e70c3 | 2297 | break; |
6de9cd9a DN |
2298 | |
2299 | default: | |
1e128c5f | 2300 | gcc_unreachable (); |
6de9cd9a DN |
2301 | } |
2302 | ||
a32e70c3 | 2303 | if (result && ignore) |
9675412f | 2304 | result = fold_ignored_result (result); |
a32e70c3 | 2305 | return result; |
6de9cd9a DN |
2306 | } |
2307 | ||
2308 | ||
206048bd | 2309 | /* Fold the statement pointed to by STMT_P. In some cases, this function may |
750628d8 DN |
2310 | replace the whole statement with a new one. Returns true iff folding |
2311 | makes any changes. */ | |
6de9cd9a | 2312 | |
750628d8 DN |
2313 | bool |
2314 | fold_stmt (tree *stmt_p) | |
6de9cd9a | 2315 | { |
750628d8 | 2316 | tree rhs, result, stmt; |
622f91ba | 2317 | struct fold_stmt_r_data fold_stmt_r_data; |
750628d8 | 2318 | bool changed = false; |
622f91ba JL |
2319 | bool inside_addr_expr = false; |
2320 | ||
2321 | fold_stmt_r_data.changed_p = &changed; | |
2322 | fold_stmt_r_data.inside_addr_expr_p = &inside_addr_expr; | |
6de9cd9a | 2323 | |
750628d8 | 2324 | stmt = *stmt_p; |
6de9cd9a | 2325 | |
750628d8 DN |
2326 | /* If we replaced constants and the statement makes pointer dereferences, |
2327 | then we may need to fold instances of *&VAR into VAR, etc. */ | |
622f91ba | 2328 | if (walk_tree (stmt_p, fold_stmt_r, &fold_stmt_r_data, NULL)) |
750628d8 DN |
2329 | { |
2330 | *stmt_p | |
2331 | = build_function_call_expr (implicit_built_in_decls[BUILT_IN_TRAP], | |
2332 | NULL); | |
6de9cd9a DN |
2333 | return true; |
2334 | } | |
2335 | ||
750628d8 DN |
2336 | rhs = get_rhs (stmt); |
2337 | if (!rhs) | |
2338 | return changed; | |
2339 | result = NULL_TREE; | |
6de9cd9a | 2340 | |
750628d8 | 2341 | if (TREE_CODE (rhs) == CALL_EXPR) |
6de9cd9a | 2342 | { |
750628d8 | 2343 | tree callee; |
6de9cd9a | 2344 | |
750628d8 DN |
2345 | /* Check for builtins that CCP can handle using information not |
2346 | available in the generic fold routines. */ | |
2347 | callee = get_callee_fndecl (rhs); | |
2348 | if (callee && DECL_BUILT_IN (callee)) | |
2349 | result = ccp_fold_builtin (stmt, rhs); | |
1809ff6b AP |
2350 | else |
2351 | { | |
2352 | /* Check for resolvable OBJ_TYPE_REF. The only sorts we can resolve | |
2353 | here are when we've propagated the address of a decl into the | |
2354 | object slot. */ | |
2355 | /* ??? Should perhaps do this in fold proper. However, doing it | |
2356 | there requires that we create a new CALL_EXPR, and that requires | |
2357 | copying EH region info to the new node. Easier to just do it | |
2358 | here where we can just smash the call operand. Also | |
2359 | CALL_EXPR_RETURN_SLOT_OPT needs to be handled correctly and | |
2360 | copied, fold_ternary does not have not information. */ | |
2361 | callee = TREE_OPERAND (rhs, 0); | |
2362 | if (TREE_CODE (callee) == OBJ_TYPE_REF | |
2363 | && lang_hooks.fold_obj_type_ref | |
2364 | && TREE_CODE (OBJ_TYPE_REF_OBJECT (callee)) == ADDR_EXPR | |
2365 | && DECL_P (TREE_OPERAND | |
2366 | (OBJ_TYPE_REF_OBJECT (callee), 0))) | |
2367 | { | |
2368 | tree t; | |
2369 | ||
2370 | /* ??? Caution: Broken ADDR_EXPR semantics means that | |
2371 | looking at the type of the operand of the addr_expr | |
2372 | can yield an array type. See silly exception in | |
2373 | check_pointer_types_r. */ | |
2374 | ||
2375 | t = TREE_TYPE (TREE_TYPE (OBJ_TYPE_REF_OBJECT (callee))); | |
2376 | t = lang_hooks.fold_obj_type_ref (callee, t); | |
2377 | if (t) | |
2378 | { | |
2379 | TREE_OPERAND (rhs, 0) = t; | |
2380 | changed = true; | |
2381 | } | |
2382 | } | |
2383 | } | |
6de9cd9a DN |
2384 | } |
2385 | ||
750628d8 DN |
2386 | /* If we couldn't fold the RHS, hand over to the generic fold routines. */ |
2387 | if (result == NULL_TREE) | |
2388 | result = fold (rhs); | |
6de9cd9a | 2389 | |
750628d8 DN |
2390 | /* Strip away useless type conversions. Both the NON_LVALUE_EXPR that |
2391 | may have been added by fold, and "useless" type conversions that might | |
2392 | now be apparent due to propagation. */ | |
2393 | STRIP_USELESS_TYPE_CONVERSION (result); | |
2394 | ||
2395 | if (result != rhs) | |
2396 | changed |= set_rhs (stmt_p, result); | |
2397 | ||
2398 | return changed; | |
6de9cd9a DN |
2399 | } |
2400 | ||
38965eb2 ZD |
2401 | /* Perform the minimal folding on statement STMT. Only operations like |
2402 | *&x created by constant propagation are handled. The statement cannot | |
2403 | be replaced with a new one. */ | |
2404 | ||
2405 | bool | |
2406 | fold_stmt_inplace (tree stmt) | |
2407 | { | |
2408 | tree old_stmt = stmt, rhs, new_rhs; | |
622f91ba | 2409 | struct fold_stmt_r_data fold_stmt_r_data; |
38965eb2 | 2410 | bool changed = false; |
622f91ba JL |
2411 | bool inside_addr_expr = false; |
2412 | ||
2413 | fold_stmt_r_data.changed_p = &changed; | |
2414 | fold_stmt_r_data.inside_addr_expr_p = &inside_addr_expr; | |
38965eb2 | 2415 | |
622f91ba | 2416 | walk_tree (&stmt, fold_stmt_r, &fold_stmt_r_data, NULL); |
38965eb2 ZD |
2417 | gcc_assert (stmt == old_stmt); |
2418 | ||
2419 | rhs = get_rhs (stmt); | |
2420 | if (!rhs || rhs == stmt) | |
2421 | return changed; | |
2422 | ||
2423 | new_rhs = fold (rhs); | |
43e364dd | 2424 | STRIP_USELESS_TYPE_CONVERSION (new_rhs); |
38965eb2 ZD |
2425 | if (new_rhs == rhs) |
2426 | return changed; | |
2427 | ||
2428 | changed |= set_rhs (&stmt, new_rhs); | |
2429 | gcc_assert (stmt == old_stmt); | |
2430 | ||
2431 | return changed; | |
2432 | } | |
6de9cd9a | 2433 | \f |
b28b1600 JJ |
2434 | /* Convert EXPR into a GIMPLE value suitable for substitution on the |
2435 | RHS of an assignment. Insert the necessary statements before | |
2e929cf3 JH |
2436 | iterator *SI_P. |
2437 | When IGNORE is set, don't worry about the return value. */ | |
b28b1600 JJ |
2438 | |
2439 | static tree | |
2e929cf3 | 2440 | convert_to_gimple_builtin (block_stmt_iterator *si_p, tree expr, bool ignore) |
b28b1600 JJ |
2441 | { |
2442 | tree_stmt_iterator ti; | |
2443 | tree stmt = bsi_stmt (*si_p); | |
2444 | tree tmp, stmts = NULL; | |
2445 | ||
2446 | push_gimplify_context (); | |
2e929cf3 JH |
2447 | if (ignore) |
2448 | { | |
2449 | tmp = build_empty_stmt (); | |
2450 | gimplify_and_add (expr, &stmts); | |
2451 | } | |
2452 | else | |
2453 | tmp = get_initialized_tmp_var (expr, &stmts, NULL); | |
b28b1600 JJ |
2454 | pop_gimplify_context (NULL); |
2455 | ||
f47c96aa AM |
2456 | if (EXPR_HAS_LOCATION (stmt)) |
2457 | annotate_all_with_locus (&stmts, EXPR_LOCATION (stmt)); | |
2458 | ||
b28b1600 JJ |
2459 | /* The replacement can expose previously unreferenced variables. */ |
2460 | for (ti = tsi_start (stmts); !tsi_end_p (ti); tsi_next (&ti)) | |
2461 | { | |
f47c96aa | 2462 | tree new_stmt = tsi_stmt (ti); |
b28b1600 | 2463 | find_new_referenced_vars (tsi_stmt_ptr (ti)); |
f47c96aa AM |
2464 | bsi_insert_before (si_p, new_stmt, BSI_NEW_STMT); |
2465 | mark_new_vars_to_rename (bsi_stmt (*si_p)); | |
2466 | bsi_next (si_p); | |
b28b1600 JJ |
2467 | } |
2468 | ||
b28b1600 JJ |
2469 | return tmp; |
2470 | } | |
2471 | ||
2472 | ||
6de9cd9a DN |
2473 | /* A simple pass that attempts to fold all builtin functions. This pass |
2474 | is run after we've propagated as many constants as we can. */ | |
2475 | ||
c2924966 | 2476 | static unsigned int |
6de9cd9a DN |
2477 | execute_fold_all_builtins (void) |
2478 | { | |
a7d6ba24 | 2479 | bool cfg_changed = false; |
6de9cd9a DN |
2480 | basic_block bb; |
2481 | FOR_EACH_BB (bb) | |
2482 | { | |
2483 | block_stmt_iterator i; | |
10a0d495 | 2484 | for (i = bsi_start (bb); !bsi_end_p (i); ) |
6de9cd9a DN |
2485 | { |
2486 | tree *stmtp = bsi_stmt_ptr (i); | |
af47810a | 2487 | tree old_stmt = *stmtp; |
6de9cd9a DN |
2488 | tree call = get_rhs (*stmtp); |
2489 | tree callee, result; | |
10a0d495 | 2490 | enum built_in_function fcode; |
6de9cd9a DN |
2491 | |
2492 | if (!call || TREE_CODE (call) != CALL_EXPR) | |
10a0d495 JJ |
2493 | { |
2494 | bsi_next (&i); | |
2495 | continue; | |
2496 | } | |
6de9cd9a DN |
2497 | callee = get_callee_fndecl (call); |
2498 | if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) | |
10a0d495 JJ |
2499 | { |
2500 | bsi_next (&i); | |
2501 | continue; | |
2502 | } | |
2503 | fcode = DECL_FUNCTION_CODE (callee); | |
6de9cd9a DN |
2504 | |
2505 | result = ccp_fold_builtin (*stmtp, call); | |
2506 | if (!result) | |
2507 | switch (DECL_FUNCTION_CODE (callee)) | |
2508 | { | |
2509 | case BUILT_IN_CONSTANT_P: | |
2510 | /* Resolve __builtin_constant_p. If it hasn't been | |
2511 | folded to integer_one_node by now, it's fairly | |
2512 | certain that the value simply isn't constant. */ | |
2513 | result = integer_zero_node; | |
2514 | break; | |
2515 | ||
2516 | default: | |
10a0d495 | 2517 | bsi_next (&i); |
6de9cd9a DN |
2518 | continue; |
2519 | } | |
2520 | ||
2521 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2522 | { | |
2523 | fprintf (dump_file, "Simplified\n "); | |
2524 | print_generic_stmt (dump_file, *stmtp, dump_flags); | |
2525 | } | |
2526 | ||
b28b1600 JJ |
2527 | if (!set_rhs (stmtp, result)) |
2528 | { | |
2e929cf3 JH |
2529 | result = convert_to_gimple_builtin (&i, result, |
2530 | TREE_CODE (old_stmt) | |
2531 | != MODIFY_EXPR); | |
e16acfcd NS |
2532 | if (result) |
2533 | { | |
2534 | bool ok = set_rhs (stmtp, result); | |
2535 | ||
2536 | gcc_assert (ok); | |
2537 | } | |
b28b1600 | 2538 | } |
386cfa6f | 2539 | mark_new_vars_to_rename (*stmtp); |
af47810a | 2540 | if (maybe_clean_or_replace_eh_stmt (old_stmt, *stmtp) |
a7d6ba24 JJ |
2541 | && tree_purge_dead_eh_edges (bb)) |
2542 | cfg_changed = true; | |
6de9cd9a DN |
2543 | |
2544 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2545 | { | |
2546 | fprintf (dump_file, "to\n "); | |
2547 | print_generic_stmt (dump_file, *stmtp, dump_flags); | |
2548 | fprintf (dump_file, "\n"); | |
2549 | } | |
10a0d495 JJ |
2550 | |
2551 | /* Retry the same statement if it changed into another | |
2552 | builtin, there might be new opportunities now. */ | |
2553 | call = get_rhs (*stmtp); | |
2554 | if (!call || TREE_CODE (call) != CALL_EXPR) | |
2555 | { | |
2556 | bsi_next (&i); | |
2557 | continue; | |
2558 | } | |
2559 | callee = get_callee_fndecl (call); | |
2560 | if (!callee | |
2561 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL | |
2562 | || DECL_FUNCTION_CODE (callee) == fcode) | |
2563 | bsi_next (&i); | |
6de9cd9a DN |
2564 | } |
2565 | } | |
a7d6ba24 JJ |
2566 | |
2567 | /* Delete unreachable blocks. */ | |
2568 | if (cfg_changed) | |
2569 | cleanup_tree_cfg (); | |
c2924966 | 2570 | return 0; |
6de9cd9a DN |
2571 | } |
2572 | ||
750628d8 | 2573 | |
6de9cd9a DN |
2574 | struct tree_opt_pass pass_fold_builtins = |
2575 | { | |
2576 | "fab", /* name */ | |
2577 | NULL, /* gate */ | |
2578 | execute_fold_all_builtins, /* execute */ | |
2579 | NULL, /* sub */ | |
2580 | NULL, /* next */ | |
2581 | 0, /* static_pass_number */ | |
2582 | 0, /* tv_id */ | |
c1b763fa | 2583 | PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */ |
6de9cd9a DN |
2584 | 0, /* properties_provided */ |
2585 | 0, /* properties_destroyed */ | |
2586 | 0, /* todo_flags_start */ | |
b28b1600 JJ |
2587 | TODO_dump_func |
2588 | | TODO_verify_ssa | |
0bca51f0 | 2589 | | TODO_update_ssa, /* todo_flags_finish */ |
9f8628ba | 2590 | 0 /* letter */ |
6de9cd9a | 2591 | }; |