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6de9cd9a | 1 | /* Conditional constant propagation pass for the GNU compiler. |
6ac01510 | 2 | Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 |
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 | |
9dcd6f09 | 11 | Free Software Foundation; either version 3, or (at your option) any |
6de9cd9a DN |
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 | |
9dcd6f09 NC |
20 | along with GCC; see the file COPYING3. If not see |
21 | <http://www.gnu.org/licenses/>. */ | |
6de9cd9a | 22 | |
0bca51f0 DN |
23 | /* Conditional constant propagation (CCP) is based on the SSA |
24 | propagation engine (tree-ssa-propagate.c). Constant assignments of | |
25 | the form VAR = CST are propagated from the assignments into uses of | |
26 | VAR, which in turn may generate new constants. The simulation uses | |
27 | a four level lattice to keep track of constant values associated | |
28 | with SSA names. Given an SSA name V_i, it may take one of the | |
29 | following values: | |
30 | ||
106dec71 ZD |
31 | UNINITIALIZED -> the initial state of the value. This value |
32 | is replaced with a correct initial value | |
33 | the first time the value is used, so the | |
34 | rest of the pass does not need to care about | |
35 | it. Using this value simplifies initialization | |
36 | of the pass, and prevents us from needlessly | |
37 | scanning statements that are never reached. | |
0bca51f0 DN |
38 | |
39 | UNDEFINED -> V_i is a local variable whose definition | |
40 | has not been processed yet. Therefore we | |
41 | don't yet know if its value is a constant | |
42 | or not. | |
43 | ||
44 | CONSTANT -> V_i has been found to hold a constant | |
45 | value C. | |
46 | ||
47 | VARYING -> V_i cannot take a constant value, or if it | |
48 | does, it is not possible to determine it | |
49 | at compile time. | |
50 | ||
51 | The core of SSA-CCP is in ccp_visit_stmt and ccp_visit_phi_node: | |
52 | ||
53 | 1- In ccp_visit_stmt, we are interested in assignments whose RHS | |
54 | evaluates into a constant and conditional jumps whose predicate | |
55 | evaluates into a boolean true or false. When an assignment of | |
56 | the form V_i = CONST is found, V_i's lattice value is set to | |
57 | CONSTANT and CONST is associated with it. This causes the | |
58 | propagation engine to add all the SSA edges coming out the | |
59 | assignment into the worklists, so that statements that use V_i | |
60 | can be visited. | |
61 | ||
62 | If the statement is a conditional with a constant predicate, we | |
63 | mark the outgoing edges as executable or not executable | |
64 | depending on the predicate's value. This is then used when | |
65 | visiting PHI nodes to know when a PHI argument can be ignored. | |
66 | ||
67 | ||
68 | 2- In ccp_visit_phi_node, if all the PHI arguments evaluate to the | |
69 | same constant C, then the LHS of the PHI is set to C. This | |
70 | evaluation is known as the "meet operation". Since one of the | |
71 | goals of this evaluation is to optimistically return constant | |
72 | values as often as possible, it uses two main short cuts: | |
73 | ||
74 | - If an argument is flowing in through a non-executable edge, it | |
75 | is ignored. This is useful in cases like this: | |
76 | ||
77 | if (PRED) | |
78 | a_9 = 3; | |
79 | else | |
80 | a_10 = 100; | |
81 | a_11 = PHI (a_9, a_10) | |
82 | ||
83 | If PRED is known to always evaluate to false, then we can | |
84 | assume that a_11 will always take its value from a_10, meaning | |
85 | that instead of consider it VARYING (a_9 and a_10 have | |
86 | different values), we can consider it CONSTANT 100. | |
87 | ||
88 | - If an argument has an UNDEFINED value, then it does not affect | |
89 | the outcome of the meet operation. If a variable V_i has an | |
90 | UNDEFINED value, it means that either its defining statement | |
91 | hasn't been visited yet or V_i has no defining statement, in | |
92 | which case the original symbol 'V' is being used | |
93 | uninitialized. Since 'V' is a local variable, the compiler | |
94 | may assume any initial value for it. | |
95 | ||
96 | ||
97 | After propagation, every variable V_i that ends up with a lattice | |
98 | value of CONSTANT will have the associated constant value in the | |
99 | array CONST_VAL[i].VALUE. That is fed into substitute_and_fold for | |
100 | final substitution and folding. | |
101 | ||
102 | ||
103 | Constant propagation in stores and loads (STORE-CCP) | |
104 | ---------------------------------------------------- | |
105 | ||
106 | While CCP has all the logic to propagate constants in GIMPLE | |
107 | registers, it is missing the ability to associate constants with | |
108 | stores and loads (i.e., pointer dereferences, structures and | |
109 | global/aliased variables). We don't keep loads and stores in | |
110 | SSA, but we do build a factored use-def web for them (in the | |
111 | virtual operands). | |
112 | ||
113 | For instance, consider the following code fragment: | |
114 | ||
115 | struct A a; | |
116 | const int B = 42; | |
117 | ||
118 | void foo (int i) | |
119 | { | |
120 | if (i > 10) | |
121 | a.a = 42; | |
122 | else | |
123 | { | |
124 | a.b = 21; | |
125 | a.a = a.b + 21; | |
126 | } | |
127 | ||
128 | if (a.a != B) | |
129 | never_executed (); | |
130 | } | |
131 | ||
132 | We should be able to deduce that the predicate 'a.a != B' is always | |
133 | false. To achieve this, we associate constant values to the SSA | |
38635499 DN |
134 | names in the VDEF operands for each store. Additionally, |
135 | since we also glob partial loads/stores with the base symbol, we | |
136 | also keep track of the memory reference where the constant value | |
137 | was stored (in the MEM_REF field of PROP_VALUE_T). For instance, | |
0bca51f0 | 138 | |
38635499 | 139 | # a_5 = VDEF <a_4> |
0bca51f0 DN |
140 | a.a = 2; |
141 | ||
142 | # VUSE <a_5> | |
143 | x_3 = a.b; | |
144 | ||
145 | In the example above, CCP will associate value '2' with 'a_5', but | |
146 | it would be wrong to replace the load from 'a.b' with '2', because | |
147 | '2' had been stored into a.a. | |
148 | ||
106dec71 ZD |
149 | Note that the initial value of virtual operands is VARYING, not |
150 | UNDEFINED. Consider, for instance global variables: | |
0bca51f0 DN |
151 | |
152 | int A; | |
153 | ||
154 | foo (int i) | |
155 | { | |
156 | if (i_3 > 10) | |
157 | A_4 = 3; | |
158 | # A_5 = PHI (A_4, A_2); | |
159 | ||
160 | # VUSE <A_5> | |
161 | A.0_6 = A; | |
162 | ||
163 | return A.0_6; | |
164 | } | |
165 | ||
166 | The value of A_2 cannot be assumed to be UNDEFINED, as it may have | |
167 | been defined outside of foo. If we were to assume it UNDEFINED, we | |
106dec71 | 168 | would erroneously optimize the above into 'return 3;'. |
0bca51f0 DN |
169 | |
170 | Though STORE-CCP is not too expensive, it does have to do more work | |
171 | than regular CCP, so it is only enabled at -O2. Both regular CCP | |
172 | and STORE-CCP use the exact same algorithm. The only distinction | |
173 | is that when doing STORE-CCP, the boolean variable DO_STORE_CCP is | |
174 | set to true. This affects the evaluation of statements and PHI | |
175 | nodes. | |
6de9cd9a DN |
176 | |
177 | References: | |
178 | ||
179 | Constant propagation with conditional branches, | |
180 | Wegman and Zadeck, ACM TOPLAS 13(2):181-210. | |
181 | ||
182 | Building an Optimizing Compiler, | |
183 | Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9. | |
184 | ||
185 | Advanced Compiler Design and Implementation, | |
186 | Steven Muchnick, Morgan Kaufmann, 1997, Section 12.6 */ | |
187 | ||
188 | #include "config.h" | |
189 | #include "system.h" | |
190 | #include "coretypes.h" | |
191 | #include "tm.h" | |
6de9cd9a | 192 | #include "tree.h" |
750628d8 | 193 | #include "flags.h" |
6de9cd9a DN |
194 | #include "rtl.h" |
195 | #include "tm_p.h" | |
750628d8 | 196 | #include "ggc.h" |
6de9cd9a | 197 | #include "basic-block.h" |
750628d8 | 198 | #include "output.h" |
750628d8 DN |
199 | #include "expr.h" |
200 | #include "function.h" | |
6de9cd9a | 201 | #include "diagnostic.h" |
750628d8 | 202 | #include "timevar.h" |
6de9cd9a | 203 | #include "tree-dump.h" |
750628d8 | 204 | #include "tree-flow.h" |
6de9cd9a | 205 | #include "tree-pass.h" |
750628d8 DN |
206 | #include "tree-ssa-propagate.h" |
207 | #include "langhooks.h" | |
ae3df618 | 208 | #include "target.h" |
6ac01510 | 209 | #include "toplev.h" |
6de9cd9a DN |
210 | |
211 | ||
212 | /* Possible lattice values. */ | |
213 | typedef enum | |
214 | { | |
106dec71 | 215 | UNINITIALIZED, |
6de9cd9a DN |
216 | UNDEFINED, |
217 | CONSTANT, | |
218 | VARYING | |
0bca51f0 | 219 | } ccp_lattice_t; |
6de9cd9a | 220 | |
0bca51f0 DN |
221 | /* Array of propagated constant values. After propagation, |
222 | CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If | |
223 | the constant is held in an SSA name representing a memory store | |
38635499 DN |
224 | (i.e., a VDEF), CONST_VAL[I].MEM_REF will contain the actual |
225 | memory reference used to store (i.e., the LHS of the assignment | |
226 | doing the store). */ | |
404f4351 | 227 | static prop_value_t *const_val; |
6de9cd9a | 228 | |
0bca51f0 DN |
229 | /* True if we are also propagating constants in stores and loads. */ |
230 | static bool do_store_ccp; | |
6de9cd9a | 231 | |
0bca51f0 | 232 | /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */ |
95eec0d6 DB |
233 | |
234 | static void | |
0bca51f0 | 235 | dump_lattice_value (FILE *outf, const char *prefix, prop_value_t val) |
95eec0d6 | 236 | { |
750628d8 | 237 | switch (val.lattice_val) |
95eec0d6 | 238 | { |
0bca51f0 DN |
239 | case UNINITIALIZED: |
240 | fprintf (outf, "%sUNINITIALIZED", prefix); | |
241 | break; | |
750628d8 DN |
242 | case UNDEFINED: |
243 | fprintf (outf, "%sUNDEFINED", prefix); | |
244 | break; | |
245 | case VARYING: | |
246 | fprintf (outf, "%sVARYING", prefix); | |
247 | break; | |
750628d8 DN |
248 | case CONSTANT: |
249 | fprintf (outf, "%sCONSTANT ", prefix); | |
0bca51f0 | 250 | print_generic_expr (outf, val.value, dump_flags); |
750628d8 DN |
251 | break; |
252 | default: | |
1e128c5f | 253 | gcc_unreachable (); |
750628d8 | 254 | } |
95eec0d6 | 255 | } |
6de9cd9a | 256 | |
6de9cd9a | 257 | |
0bca51f0 DN |
258 | /* Print lattice value VAL to stderr. */ |
259 | ||
260 | void debug_lattice_value (prop_value_t val); | |
261 | ||
262 | void | |
263 | debug_lattice_value (prop_value_t val) | |
264 | { | |
265 | dump_lattice_value (stderr, "", val); | |
266 | fprintf (stderr, "\n"); | |
267 | } | |
6de9cd9a | 268 | |
6de9cd9a | 269 | |
688e936d RH |
270 | /* The regular is_gimple_min_invariant does a shallow test of the object. |
271 | It assumes that full gimplification has happened, or will happen on the | |
272 | object. For a value coming from DECL_INITIAL, this is not true, so we | |
6416ae7f | 273 | have to be more strict ourselves. */ |
688e936d RH |
274 | |
275 | static bool | |
276 | ccp_decl_initial_min_invariant (tree t) | |
277 | { | |
278 | if (!is_gimple_min_invariant (t)) | |
279 | return false; | |
280 | if (TREE_CODE (t) == ADDR_EXPR) | |
281 | { | |
282 | /* Inline and unroll is_gimple_addressable. */ | |
283 | while (1) | |
284 | { | |
285 | t = TREE_OPERAND (t, 0); | |
286 | if (is_gimple_id (t)) | |
287 | return true; | |
288 | if (!handled_component_p (t)) | |
289 | return false; | |
290 | } | |
291 | } | |
292 | return true; | |
293 | } | |
294 | ||
fc9962ee ZD |
295 | /* If SYM is a constant variable with known value, return the value. |
296 | NULL_TREE is returned otherwise. */ | |
297 | ||
ed97ddc6 | 298 | tree |
fc9962ee ZD |
299 | get_symbol_constant_value (tree sym) |
300 | { | |
301 | if (TREE_STATIC (sym) | |
302 | && TREE_READONLY (sym) | |
ed97ddc6 | 303 | && !MTAG_P (sym)) |
fc9962ee ZD |
304 | { |
305 | tree val = DECL_INITIAL (sym); | |
306 | if (val | |
307 | && ccp_decl_initial_min_invariant (val)) | |
308 | return val; | |
b0940154 | 309 | /* Variables declared 'const' without an initializer |
ed97ddc6 RG |
310 | have zero as the intializer if they may not be |
311 | overridden at link or run time. */ | |
b0940154 | 312 | if (!val |
ed97ddc6 | 313 | && targetm.binds_local_p (sym) |
b0940154 AP |
314 | && (INTEGRAL_TYPE_P (TREE_TYPE (sym)) |
315 | || SCALAR_FLOAT_TYPE_P (TREE_TYPE (sym)))) | |
316 | return fold_convert (TREE_TYPE (sym), integer_zero_node); | |
fc9962ee ZD |
317 | } |
318 | ||
319 | return NULL_TREE; | |
320 | } | |
688e936d | 321 | |
0bca51f0 DN |
322 | /* Compute a default value for variable VAR and store it in the |
323 | CONST_VAL array. The following rules are used to get default | |
324 | values: | |
95eec0d6 | 325 | |
0bca51f0 DN |
326 | 1- Global and static variables that are declared constant are |
327 | considered CONSTANT. | |
328 | ||
329 | 2- Any other value is considered UNDEFINED. This is useful when | |
750628d8 DN |
330 | considering PHI nodes. PHI arguments that are undefined do not |
331 | change the constant value of the PHI node, which allows for more | |
0bca51f0 | 332 | constants to be propagated. |
6de9cd9a | 333 | |
0bca51f0 DN |
334 | 3- If SSA_NAME_VALUE is set and it is a constant, its value is |
335 | used. | |
6de9cd9a | 336 | |
0bca51f0 DN |
337 | 4- Variables defined by statements other than assignments and PHI |
338 | nodes are considered VARYING. | |
6de9cd9a | 339 | |
106dec71 ZD |
340 | 5- Initial values of variables that are not GIMPLE registers are |
341 | considered VARYING. */ | |
6de9cd9a | 342 | |
0bca51f0 DN |
343 | static prop_value_t |
344 | get_default_value (tree var) | |
345 | { | |
346 | tree sym = SSA_NAME_VAR (var); | |
347 | prop_value_t val = { UNINITIALIZED, NULL_TREE, NULL_TREE }; | |
fc9962ee | 348 | tree cst_val; |
106dec71 | 349 | |
0bca51f0 | 350 | if (!do_store_ccp && !is_gimple_reg (var)) |
6de9cd9a | 351 | { |
0bca51f0 DN |
352 | /* Short circuit for regular CCP. We are not interested in any |
353 | non-register when DO_STORE_CCP is false. */ | |
750628d8 | 354 | val.lattice_val = VARYING; |
6de9cd9a | 355 | } |
0bca51f0 DN |
356 | else if (SSA_NAME_VALUE (var) |
357 | && is_gimple_min_invariant (SSA_NAME_VALUE (var))) | |
750628d8 | 358 | { |
0bca51f0 DN |
359 | val.lattice_val = CONSTANT; |
360 | val.value = SSA_NAME_VALUE (var); | |
750628d8 | 361 | } |
fc9962ee | 362 | else if ((cst_val = get_symbol_constant_value (sym)) != NULL_TREE) |
750628d8 | 363 | { |
0bca51f0 DN |
364 | /* Globals and static variables declared 'const' take their |
365 | initial value. */ | |
366 | val.lattice_val = CONSTANT; | |
fc9962ee | 367 | val.value = cst_val; |
0bca51f0 | 368 | val.mem_ref = sym; |
750628d8 DN |
369 | } |
370 | else | |
371 | { | |
750628d8 | 372 | tree stmt = SSA_NAME_DEF_STMT (var); |
6de9cd9a | 373 | |
0bca51f0 DN |
374 | if (IS_EMPTY_STMT (stmt)) |
375 | { | |
376 | /* Variables defined by an empty statement are those used | |
377 | before being initialized. If VAR is a local variable, we | |
106dec71 ZD |
378 | can assume initially that it is UNDEFINED, otherwise we must |
379 | consider it VARYING. */ | |
0bca51f0 DN |
380 | if (is_gimple_reg (sym) && TREE_CODE (sym) != PARM_DECL) |
381 | val.lattice_val = UNDEFINED; | |
0bca51f0 | 382 | else |
750628d8 DN |
383 | val.lattice_val = VARYING; |
384 | } | |
07beea0d | 385 | else if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT |
0bca51f0 DN |
386 | || TREE_CODE (stmt) == PHI_NODE) |
387 | { | |
388 | /* Any other variable defined by an assignment or a PHI node | |
106dec71 ZD |
389 | is considered UNDEFINED. */ |
390 | val.lattice_val = UNDEFINED; | |
0bca51f0 DN |
391 | } |
392 | else | |
393 | { | |
394 | /* Otherwise, VAR will never take on a constant value. */ | |
395 | val.lattice_val = VARYING; | |
396 | } | |
750628d8 | 397 | } |
6de9cd9a | 398 | |
750628d8 DN |
399 | return val; |
400 | } | |
6de9cd9a | 401 | |
6de9cd9a | 402 | |
106dec71 | 403 | /* Get the constant value associated with variable VAR. */ |
6de9cd9a | 404 | |
106dec71 ZD |
405 | static inline prop_value_t * |
406 | get_value (tree var) | |
0bca51f0 | 407 | { |
ed97ddc6 | 408 | prop_value_t *val; |
106dec71 | 409 | |
ed97ddc6 RG |
410 | if (const_val == NULL) |
411 | return NULL; | |
412 | ||
413 | val = &const_val[SSA_NAME_VERSION (var)]; | |
106dec71 | 414 | if (val->lattice_val == UNINITIALIZED) |
6de9cd9a DN |
415 | *val = get_default_value (var); |
416 | ||
417 | return val; | |
418 | } | |
419 | ||
106dec71 ZD |
420 | /* Sets the value associated with VAR to VARYING. */ |
421 | ||
422 | static inline void | |
423 | set_value_varying (tree var) | |
424 | { | |
425 | prop_value_t *val = &const_val[SSA_NAME_VERSION (var)]; | |
426 | ||
427 | val->lattice_val = VARYING; | |
428 | val->value = NULL_TREE; | |
429 | val->mem_ref = NULL_TREE; | |
430 | } | |
6de9cd9a | 431 | |
fbb5445b L |
432 | /* For float types, modify the value of VAL to make ccp work correctly |
433 | for non-standard values (-0, NaN): | |
434 | ||
435 | If HONOR_SIGNED_ZEROS is false, and VAL = -0, we canonicalize it to 0. | |
436 | If HONOR_NANS is false, and VAL is NaN, we canonicalize it to UNDEFINED. | |
437 | This is to fix the following problem (see PR 29921): Suppose we have | |
438 | ||
439 | x = 0.0 * y | |
440 | ||
441 | and we set value of y to NaN. This causes value of x to be set to NaN. | |
442 | When we later determine that y is in fact VARYING, fold uses the fact | |
443 | that HONOR_NANS is false, and we try to change the value of x to 0, | |
444 | causing an ICE. With HONOR_NANS being false, the real appearance of | |
445 | NaN would cause undefined behavior, though, so claiming that y (and x) | |
446 | are UNDEFINED initially is correct. */ | |
447 | ||
448 | static void | |
449 | canonicalize_float_value (prop_value_t *val) | |
450 | { | |
451 | enum machine_mode mode; | |
452 | tree type; | |
453 | REAL_VALUE_TYPE d; | |
454 | ||
455 | if (val->lattice_val != CONSTANT | |
456 | || TREE_CODE (val->value) != REAL_CST) | |
457 | return; | |
458 | ||
459 | d = TREE_REAL_CST (val->value); | |
460 | type = TREE_TYPE (val->value); | |
461 | mode = TYPE_MODE (type); | |
462 | ||
463 | if (!HONOR_SIGNED_ZEROS (mode) | |
464 | && REAL_VALUE_MINUS_ZERO (d)) | |
465 | { | |
466 | val->value = build_real (type, dconst0); | |
467 | return; | |
468 | } | |
469 | ||
470 | if (!HONOR_NANS (mode) | |
471 | && REAL_VALUE_ISNAN (d)) | |
472 | { | |
473 | val->lattice_val = UNDEFINED; | |
474 | val->value = NULL; | |
475 | val->mem_ref = NULL; | |
476 | return; | |
477 | } | |
478 | } | |
479 | ||
0bca51f0 DN |
480 | /* Set the value for variable VAR to NEW_VAL. Return true if the new |
481 | value is different from VAR's previous value. */ | |
6de9cd9a | 482 | |
750628d8 | 483 | static bool |
0bca51f0 | 484 | set_lattice_value (tree var, prop_value_t new_val) |
6de9cd9a | 485 | { |
106dec71 | 486 | prop_value_t *old_val = get_value (var); |
0bca51f0 | 487 | |
fbb5445b L |
488 | canonicalize_float_value (&new_val); |
489 | ||
0bca51f0 | 490 | /* Lattice transitions must always be monotonically increasing in |
106dec71 ZD |
491 | value. If *OLD_VAL and NEW_VAL are the same, return false to |
492 | inform the caller that this was a non-transition. */ | |
493 | ||
fc9962ee | 494 | gcc_assert (old_val->lattice_val < new_val.lattice_val |
0bca51f0 | 495 | || (old_val->lattice_val == new_val.lattice_val |
fc9962ee ZD |
496 | && ((!old_val->value && !new_val.value) |
497 | || operand_equal_p (old_val->value, new_val.value, 0)) | |
106dec71 | 498 | && old_val->mem_ref == new_val.mem_ref)); |
0bca51f0 DN |
499 | |
500 | if (old_val->lattice_val != new_val.lattice_val) | |
6de9cd9a | 501 | { |
750628d8 DN |
502 | if (dump_file && (dump_flags & TDF_DETAILS)) |
503 | { | |
0bca51f0 | 504 | dump_lattice_value (dump_file, "Lattice value changed to ", new_val); |
106dec71 | 505 | fprintf (dump_file, ". Adding SSA edges to worklist.\n"); |
750628d8 DN |
506 | } |
507 | ||
0bca51f0 DN |
508 | *old_val = new_val; |
509 | ||
106dec71 ZD |
510 | gcc_assert (new_val.lattice_val != UNDEFINED); |
511 | return true; | |
6de9cd9a | 512 | } |
750628d8 DN |
513 | |
514 | return false; | |
6de9cd9a DN |
515 | } |
516 | ||
517 | ||
0bca51f0 | 518 | /* Return the likely CCP lattice value for STMT. |
6de9cd9a | 519 | |
750628d8 | 520 | If STMT has no operands, then return CONSTANT. |
6de9cd9a | 521 | |
7f879c96 RG |
522 | Else if undefinedness of operands of STMT cause its value to be |
523 | undefined, then return UNDEFINED. | |
6de9cd9a | 524 | |
750628d8 | 525 | Else if any operands of STMT are constants, then return CONSTANT. |
6de9cd9a | 526 | |
750628d8 | 527 | Else return VARYING. */ |
6de9cd9a | 528 | |
0bca51f0 | 529 | static ccp_lattice_t |
750628d8 DN |
530 | likely_value (tree stmt) |
531 | { | |
7f879c96 | 532 | bool has_constant_operand, has_undefined_operand, all_undefined_operands; |
750628d8 DN |
533 | stmt_ann_t ann; |
534 | tree use; | |
535 | ssa_op_iter iter; | |
6de9cd9a | 536 | |
750628d8 | 537 | ann = stmt_ann (stmt); |
0bca51f0 DN |
538 | |
539 | /* If the statement has volatile operands, it won't fold to a | |
540 | constant value. */ | |
541 | if (ann->has_volatile_ops) | |
542 | return VARYING; | |
543 | ||
544 | /* If we are not doing store-ccp, statements with loads | |
545 | and/or stores will never fold into a constant. */ | |
546 | if (!do_store_ccp | |
ff88c5aa | 547 | && !ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)) |
750628d8 | 548 | return VARYING; |
6de9cd9a | 549 | |
0bca51f0 DN |
550 | |
551 | /* A CALL_EXPR is assumed to be varying. NOTE: This may be overly | |
552 | conservative, in the presence of const and pure calls. */ | |
750628d8 DN |
553 | if (get_call_expr_in (stmt) != NULL_TREE) |
554 | return VARYING; | |
6de9cd9a | 555 | |
0bca51f0 DN |
556 | /* Anything other than assignments and conditional jumps are not |
557 | interesting for CCP. */ | |
07beea0d | 558 | if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT |
106dec71 | 559 | && !(TREE_CODE (stmt) == RETURN_EXPR && get_rhs (stmt) != NULL_TREE) |
0bca51f0 DN |
560 | && TREE_CODE (stmt) != COND_EXPR |
561 | && TREE_CODE (stmt) != SWITCH_EXPR) | |
562 | return VARYING; | |
563 | ||
a318e3ac SB |
564 | if (is_gimple_min_invariant (get_rhs (stmt))) |
565 | return CONSTANT; | |
566 | ||
106dec71 | 567 | has_constant_operand = false; |
7f879c96 RG |
568 | has_undefined_operand = false; |
569 | all_undefined_operands = true; | |
106dec71 | 570 | FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE | SSA_OP_VUSE) |
750628d8 | 571 | { |
106dec71 | 572 | prop_value_t *val = get_value (use); |
750628d8 | 573 | |
106dec71 | 574 | if (val->lattice_val == UNDEFINED) |
7f879c96 RG |
575 | has_undefined_operand = true; |
576 | else | |
577 | all_undefined_operands = false; | |
0bca51f0 | 578 | |
750628d8 | 579 | if (val->lattice_val == CONSTANT) |
106dec71 | 580 | has_constant_operand = true; |
6de9cd9a | 581 | } |
750628d8 | 582 | |
7f879c96 RG |
583 | /* If the operation combines operands like COMPLEX_EXPR make sure to |
584 | not mark the result UNDEFINED if only one part of the result is | |
585 | undefined. */ | |
586 | if (has_undefined_operand | |
587 | && all_undefined_operands) | |
588 | return UNDEFINED; | |
589 | else if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT | |
590 | && has_undefined_operand) | |
591 | { | |
592 | switch (TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1))) | |
593 | { | |
594 | /* Unary operators are handled with all_undefined_operands. */ | |
595 | case PLUS_EXPR: | |
596 | case MINUS_EXPR: | |
7f879c96 | 597 | case POINTER_PLUS_EXPR: |
7f879c96 RG |
598 | /* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected. |
599 | Not bitwise operators, one VARYING operand may specify the | |
600 | result completely. Not logical operators for the same reason. | |
0cedb9e9 RG |
601 | Not COMPLEX_EXPR as one VARYING operand makes the result partly |
602 | not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because | |
603 | the undefined operand may be promoted. */ | |
7f879c96 RG |
604 | return UNDEFINED; |
605 | ||
606 | default: | |
607 | ; | |
608 | } | |
609 | } | |
610 | /* If there was an UNDEFINED operand but the result may be not UNDEFINED | |
611 | fall back to VARYING even if there were CONSTANT operands. */ | |
612 | if (has_undefined_operand) | |
613 | return VARYING; | |
614 | ||
106dec71 ZD |
615 | if (has_constant_operand |
616 | /* We do not consider virtual operands here -- load from read-only | |
617 | memory may have only VARYING virtual operands, but still be | |
618 | constant. */ | |
619 | || ZERO_SSA_OPERANDS (stmt, SSA_OP_USE)) | |
0bca51f0 DN |
620 | return CONSTANT; |
621 | ||
106dec71 | 622 | return VARYING; |
6de9cd9a DN |
623 | } |
624 | ||
106dec71 ZD |
625 | /* Returns true if STMT cannot be constant. */ |
626 | ||
627 | static bool | |
628 | surely_varying_stmt_p (tree stmt) | |
629 | { | |
630 | /* If the statement has operands that we cannot handle, it cannot be | |
631 | constant. */ | |
632 | if (stmt_ann (stmt)->has_volatile_ops) | |
633 | return true; | |
634 | ||
635 | if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)) | |
636 | { | |
637 | if (!do_store_ccp) | |
638 | return true; | |
639 | ||
640 | /* We can only handle simple loads and stores. */ | |
641 | if (!stmt_makes_single_load (stmt) | |
642 | && !stmt_makes_single_store (stmt)) | |
643 | return true; | |
644 | } | |
645 | ||
646 | /* If it contains a call, it is varying. */ | |
647 | if (get_call_expr_in (stmt) != NULL_TREE) | |
648 | return true; | |
649 | ||
650 | /* Anything other than assignments and conditional jumps are not | |
651 | interesting for CCP. */ | |
07beea0d | 652 | if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT |
106dec71 ZD |
653 | && !(TREE_CODE (stmt) == RETURN_EXPR && get_rhs (stmt) != NULL_TREE) |
654 | && TREE_CODE (stmt) != COND_EXPR | |
655 | && TREE_CODE (stmt) != SWITCH_EXPR) | |
656 | return true; | |
657 | ||
658 | return false; | |
659 | } | |
6de9cd9a | 660 | |
750628d8 | 661 | /* Initialize local data structures for CCP. */ |
6de9cd9a DN |
662 | |
663 | static void | |
750628d8 | 664 | ccp_initialize (void) |
6de9cd9a | 665 | { |
750628d8 | 666 | basic_block bb; |
6de9cd9a | 667 | |
b9eae1a9 | 668 | const_val = XCNEWVEC (prop_value_t, num_ssa_names); |
6de9cd9a | 669 | |
750628d8 DN |
670 | /* Initialize simulation flags for PHI nodes and statements. */ |
671 | FOR_EACH_BB (bb) | |
6de9cd9a | 672 | { |
750628d8 | 673 | block_stmt_iterator i; |
6de9cd9a | 674 | |
750628d8 DN |
675 | for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i)) |
676 | { | |
750628d8 | 677 | tree stmt = bsi_stmt (i); |
106dec71 | 678 | bool is_varying = surely_varying_stmt_p (stmt); |
6de9cd9a | 679 | |
106dec71 | 680 | if (is_varying) |
750628d8 | 681 | { |
0bca51f0 DN |
682 | tree def; |
683 | ssa_op_iter iter; | |
684 | ||
685 | /* If the statement will not produce a constant, mark | |
686 | all its outputs VARYING. */ | |
687 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) | |
106dec71 ZD |
688 | { |
689 | if (is_varying) | |
690 | set_value_varying (def); | |
691 | } | |
750628d8 DN |
692 | } |
693 | ||
750628d8 DN |
694 | DONT_SIMULATE_AGAIN (stmt) = is_varying; |
695 | } | |
6de9cd9a DN |
696 | } |
697 | ||
106dec71 ZD |
698 | /* Now process PHI nodes. We never set DONT_SIMULATE_AGAIN on phi node, |
699 | since we do not know which edges are executable yet, except for | |
700 | phi nodes for virtual operands when we do not do store ccp. */ | |
750628d8 | 701 | FOR_EACH_BB (bb) |
6de9cd9a | 702 | { |
0bca51f0 | 703 | tree phi; |
750628d8 DN |
704 | |
705 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) | |
706 | { | |
106dec71 ZD |
707 | if (!do_store_ccp && !is_gimple_reg (PHI_RESULT (phi))) |
708 | DONT_SIMULATE_AGAIN (phi) = true; | |
709 | else | |
710 | DONT_SIMULATE_AGAIN (phi) = false; | |
750628d8 | 711 | } |
6de9cd9a | 712 | } |
750628d8 | 713 | } |
6de9cd9a | 714 | |
6de9cd9a | 715 | |
0bca51f0 | 716 | /* Do final substitution of propagated values, cleanup the flowgraph and |
3253eafb | 717 | free allocated storage. |
6de9cd9a | 718 | |
3253eafb JH |
719 | Return TRUE when something was optimized. */ |
720 | ||
721 | static bool | |
0bca51f0 | 722 | ccp_finalize (void) |
6de9cd9a | 723 | { |
0bca51f0 | 724 | /* Perform substitutions based on the known constant values. */ |
3253eafb | 725 | bool something_changed = substitute_and_fold (const_val, false); |
6de9cd9a | 726 | |
0bca51f0 | 727 | free (const_val); |
ed97ddc6 | 728 | const_val = NULL; |
3253eafb | 729 | return something_changed;; |
6de9cd9a DN |
730 | } |
731 | ||
732 | ||
0bca51f0 DN |
733 | /* Compute the meet operator between *VAL1 and *VAL2. Store the result |
734 | in VAL1. | |
735 | ||
736 | any M UNDEFINED = any | |
0bca51f0 DN |
737 | any M VARYING = VARYING |
738 | Ci M Cj = Ci if (i == j) | |
739 | Ci M Cj = VARYING if (i != j) | |
106dec71 | 740 | */ |
6de9cd9a DN |
741 | |
742 | static void | |
0bca51f0 | 743 | ccp_lattice_meet (prop_value_t *val1, prop_value_t *val2) |
6de9cd9a | 744 | { |
0bca51f0 | 745 | if (val1->lattice_val == UNDEFINED) |
6de9cd9a | 746 | { |
0bca51f0 DN |
747 | /* UNDEFINED M any = any */ |
748 | *val1 = *val2; | |
750628d8 | 749 | } |
0bca51f0 | 750 | else if (val2->lattice_val == UNDEFINED) |
195da47b | 751 | { |
0bca51f0 DN |
752 | /* any M UNDEFINED = any |
753 | Nothing to do. VAL1 already contains the value we want. */ | |
754 | ; | |
195da47b | 755 | } |
0bca51f0 DN |
756 | else if (val1->lattice_val == VARYING |
757 | || val2->lattice_val == VARYING) | |
750628d8 | 758 | { |
0bca51f0 DN |
759 | /* any M VARYING = VARYING. */ |
760 | val1->lattice_val = VARYING; | |
761 | val1->value = NULL_TREE; | |
762 | val1->mem_ref = NULL_TREE; | |
750628d8 | 763 | } |
0bca51f0 DN |
764 | else if (val1->lattice_val == CONSTANT |
765 | && val2->lattice_val == CONSTANT | |
766 | && simple_cst_equal (val1->value, val2->value) == 1 | |
767 | && (!do_store_ccp | |
a318e3ac SB |
768 | || (val1->mem_ref && val2->mem_ref |
769 | && operand_equal_p (val1->mem_ref, val2->mem_ref, 0)))) | |
750628d8 | 770 | { |
0bca51f0 DN |
771 | /* Ci M Cj = Ci if (i == j) |
772 | Ci M Cj = VARYING if (i != j) | |
773 | ||
774 | If these two values come from memory stores, make sure that | |
775 | they come from the same memory reference. */ | |
776 | val1->lattice_val = CONSTANT; | |
777 | val1->value = val1->value; | |
778 | val1->mem_ref = val1->mem_ref; | |
750628d8 DN |
779 | } |
780 | else | |
781 | { | |
0bca51f0 DN |
782 | /* Any other combination is VARYING. */ |
783 | val1->lattice_val = VARYING; | |
784 | val1->value = NULL_TREE; | |
785 | val1->mem_ref = NULL_TREE; | |
750628d8 | 786 | } |
6de9cd9a DN |
787 | } |
788 | ||
789 | ||
750628d8 DN |
790 | /* Loop through the PHI_NODE's parameters for BLOCK and compare their |
791 | lattice values to determine PHI_NODE's lattice value. The value of a | |
0bca51f0 | 792 | PHI node is determined calling ccp_lattice_meet with all the arguments |
750628d8 | 793 | of the PHI node that are incoming via executable edges. */ |
6de9cd9a | 794 | |
750628d8 DN |
795 | static enum ssa_prop_result |
796 | ccp_visit_phi_node (tree phi) | |
6de9cd9a | 797 | { |
750628d8 | 798 | int i; |
0bca51f0 | 799 | prop_value_t *old_val, new_val; |
6de9cd9a | 800 | |
750628d8 | 801 | if (dump_file && (dump_flags & TDF_DETAILS)) |
6de9cd9a | 802 | { |
750628d8 DN |
803 | fprintf (dump_file, "\nVisiting PHI node: "); |
804 | print_generic_expr (dump_file, phi, dump_flags); | |
6de9cd9a | 805 | } |
6de9cd9a | 806 | |
106dec71 | 807 | old_val = get_value (PHI_RESULT (phi)); |
750628d8 DN |
808 | switch (old_val->lattice_val) |
809 | { | |
810 | case VARYING: | |
0bca51f0 | 811 | return SSA_PROP_VARYING; |
6de9cd9a | 812 | |
750628d8 DN |
813 | case CONSTANT: |
814 | new_val = *old_val; | |
815 | break; | |
6de9cd9a | 816 | |
750628d8 | 817 | case UNDEFINED: |
750628d8 | 818 | new_val.lattice_val = UNDEFINED; |
0bca51f0 DN |
819 | new_val.value = NULL_TREE; |
820 | new_val.mem_ref = NULL_TREE; | |
750628d8 | 821 | break; |
6de9cd9a | 822 | |
750628d8 | 823 | default: |
1e128c5f | 824 | gcc_unreachable (); |
750628d8 | 825 | } |
6de9cd9a | 826 | |
750628d8 DN |
827 | for (i = 0; i < PHI_NUM_ARGS (phi); i++) |
828 | { | |
0bca51f0 DN |
829 | /* Compute the meet operator over all the PHI arguments flowing |
830 | through executable edges. */ | |
750628d8 | 831 | edge e = PHI_ARG_EDGE (phi, i); |
6de9cd9a | 832 | |
750628d8 DN |
833 | if (dump_file && (dump_flags & TDF_DETAILS)) |
834 | { | |
835 | fprintf (dump_file, | |
836 | "\n Argument #%d (%d -> %d %sexecutable)\n", | |
837 | i, e->src->index, e->dest->index, | |
838 | (e->flags & EDGE_EXECUTABLE) ? "" : "not "); | |
839 | } | |
840 | ||
841 | /* If the incoming edge is executable, Compute the meet operator for | |
842 | the existing value of the PHI node and the current PHI argument. */ | |
843 | if (e->flags & EDGE_EXECUTABLE) | |
844 | { | |
0bca51f0 DN |
845 | tree arg = PHI_ARG_DEF (phi, i); |
846 | prop_value_t arg_val; | |
6de9cd9a | 847 | |
0bca51f0 | 848 | if (is_gimple_min_invariant (arg)) |
750628d8 | 849 | { |
0bca51f0 DN |
850 | arg_val.lattice_val = CONSTANT; |
851 | arg_val.value = arg; | |
852 | arg_val.mem_ref = NULL_TREE; | |
750628d8 DN |
853 | } |
854 | else | |
106dec71 | 855 | arg_val = *(get_value (arg)); |
6de9cd9a | 856 | |
0bca51f0 | 857 | ccp_lattice_meet (&new_val, &arg_val); |
6de9cd9a | 858 | |
750628d8 DN |
859 | if (dump_file && (dump_flags & TDF_DETAILS)) |
860 | { | |
861 | fprintf (dump_file, "\t"); | |
0bca51f0 DN |
862 | print_generic_expr (dump_file, arg, dump_flags); |
863 | dump_lattice_value (dump_file, "\tValue: ", arg_val); | |
750628d8 DN |
864 | fprintf (dump_file, "\n"); |
865 | } | |
6de9cd9a | 866 | |
750628d8 DN |
867 | if (new_val.lattice_val == VARYING) |
868 | break; | |
869 | } | |
870 | } | |
6de9cd9a DN |
871 | |
872 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
750628d8 DN |
873 | { |
874 | dump_lattice_value (dump_file, "\n PHI node value: ", new_val); | |
875 | fprintf (dump_file, "\n\n"); | |
876 | } | |
877 | ||
106dec71 | 878 | /* Make the transition to the new value. */ |
750628d8 DN |
879 | if (set_lattice_value (PHI_RESULT (phi), new_val)) |
880 | { | |
881 | if (new_val.lattice_val == VARYING) | |
882 | return SSA_PROP_VARYING; | |
883 | else | |
884 | return SSA_PROP_INTERESTING; | |
885 | } | |
886 | else | |
887 | return SSA_PROP_NOT_INTERESTING; | |
6de9cd9a DN |
888 | } |
889 | ||
890 | ||
750628d8 DN |
891 | /* CCP specific front-end to the non-destructive constant folding |
892 | routines. | |
6de9cd9a DN |
893 | |
894 | Attempt to simplify the RHS of STMT knowing that one or more | |
895 | operands are constants. | |
896 | ||
897 | If simplification is possible, return the simplified RHS, | |
898 | otherwise return the original RHS. */ | |
899 | ||
900 | static tree | |
901 | ccp_fold (tree stmt) | |
902 | { | |
903 | tree rhs = get_rhs (stmt); | |
904 | enum tree_code code = TREE_CODE (rhs); | |
6615c446 | 905 | enum tree_code_class kind = TREE_CODE_CLASS (code); |
6de9cd9a DN |
906 | tree retval = NULL_TREE; |
907 | ||
6de9cd9a | 908 | if (TREE_CODE (rhs) == SSA_NAME) |
0bca51f0 DN |
909 | { |
910 | /* If the RHS is an SSA_NAME, return its known constant value, | |
911 | if any. */ | |
106dec71 | 912 | return get_value (rhs)->value; |
0bca51f0 DN |
913 | } |
914 | else if (do_store_ccp && stmt_makes_single_load (stmt)) | |
915 | { | |
916 | /* If the RHS is a memory load, see if the VUSEs associated with | |
917 | it are a valid constant for that memory load. */ | |
918 | prop_value_t *val = get_value_loaded_by (stmt, const_val); | |
add9e6d3 AP |
919 | if (val && val->mem_ref) |
920 | { | |
921 | if (operand_equal_p (val->mem_ref, rhs, 0)) | |
922 | return val->value; | |
923 | ||
924 | /* If RHS is extracting REALPART_EXPR or IMAGPART_EXPR of a | |
925 | complex type with a known constant value, return it. */ | |
926 | if ((TREE_CODE (rhs) == REALPART_EXPR | |
927 | || TREE_CODE (rhs) == IMAGPART_EXPR) | |
928 | && operand_equal_p (val->mem_ref, TREE_OPERAND (rhs, 0), 0)) | |
929 | return fold_build1 (TREE_CODE (rhs), TREE_TYPE (rhs), val->value); | |
930 | } | |
931 | return NULL_TREE; | |
0bca51f0 | 932 | } |
6de9cd9a DN |
933 | |
934 | /* Unary operators. Note that we know the single operand must | |
935 | be a constant. So this should almost always return a | |
936 | simplified RHS. */ | |
6615c446 | 937 | if (kind == tcc_unary) |
6de9cd9a DN |
938 | { |
939 | /* Handle unary operators which can appear in GIMPLE form. */ | |
940 | tree op0 = TREE_OPERAND (rhs, 0); | |
941 | ||
942 | /* Simplify the operand down to a constant. */ | |
943 | if (TREE_CODE (op0) == SSA_NAME) | |
944 | { | |
106dec71 | 945 | prop_value_t *val = get_value (op0); |
6de9cd9a | 946 | if (val->lattice_val == CONSTANT) |
106dec71 | 947 | op0 = get_value (op0)->value; |
6de9cd9a DN |
948 | } |
949 | ||
078152a2 | 950 | if ((code == NOP_EXPR || code == CONVERT_EXPR) |
36618b93 | 951 | && useless_type_conversion_p (TREE_TYPE (rhs), TREE_TYPE (op0))) |
078152a2 | 952 | return op0; |
615bc06a | 953 | return fold_unary (code, TREE_TYPE (rhs), op0); |
6de9cd9a DN |
954 | } |
955 | ||
956 | /* Binary and comparison operators. We know one or both of the | |
957 | operands are constants. */ | |
6615c446 JO |
958 | else if (kind == tcc_binary |
959 | || kind == tcc_comparison | |
6de9cd9a DN |
960 | || code == TRUTH_AND_EXPR |
961 | || code == TRUTH_OR_EXPR | |
962 | || code == TRUTH_XOR_EXPR) | |
963 | { | |
964 | /* Handle binary and comparison operators that can appear in | |
965 | GIMPLE form. */ | |
966 | tree op0 = TREE_OPERAND (rhs, 0); | |
967 | tree op1 = TREE_OPERAND (rhs, 1); | |
968 | ||
969 | /* Simplify the operands down to constants when appropriate. */ | |
970 | if (TREE_CODE (op0) == SSA_NAME) | |
971 | { | |
106dec71 | 972 | prop_value_t *val = get_value (op0); |
6de9cd9a | 973 | if (val->lattice_val == CONSTANT) |
0bca51f0 | 974 | op0 = val->value; |
6de9cd9a DN |
975 | } |
976 | ||
977 | if (TREE_CODE (op1) == SSA_NAME) | |
978 | { | |
106dec71 | 979 | prop_value_t *val = get_value (op1); |
6de9cd9a | 980 | if (val->lattice_val == CONSTANT) |
0bca51f0 | 981 | op1 = val->value; |
6de9cd9a DN |
982 | } |
983 | ||
615bc06a | 984 | return fold_binary (code, TREE_TYPE (rhs), op0, op1); |
6de9cd9a DN |
985 | } |
986 | ||
87e1e42b RG |
987 | else if (kind == tcc_declaration) |
988 | return get_symbol_constant_value (rhs); | |
989 | ||
990 | else if (kind == tcc_reference) | |
991 | return fold_const_aggregate_ref (rhs); | |
992 | ||
6de9cd9a | 993 | /* We may be able to fold away calls to builtin functions if their |
9cf737f8 | 994 | arguments are constants. */ |
6de9cd9a | 995 | else if (code == CALL_EXPR |
5039610b SL |
996 | && TREE_CODE (CALL_EXPR_FN (rhs)) == ADDR_EXPR |
997 | && TREE_CODE (TREE_OPERAND (CALL_EXPR_FN (rhs), 0)) == FUNCTION_DECL | |
998 | && DECL_BUILT_IN (TREE_OPERAND (CALL_EXPR_FN (rhs), 0))) | |
6de9cd9a | 999 | { |
f47c96aa | 1000 | if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_USE)) |
6de9cd9a | 1001 | { |
f47c96aa | 1002 | tree *orig, var; |
f47c96aa AM |
1003 | size_t i = 0; |
1004 | ssa_op_iter iter; | |
1005 | use_operand_p var_p; | |
6de9cd9a DN |
1006 | |
1007 | /* Preserve the original values of every operand. */ | |
858904db | 1008 | orig = XNEWVEC (tree, NUM_SSA_OPERANDS (stmt, SSA_OP_USE)); |
f47c96aa AM |
1009 | FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_USE) |
1010 | orig[i++] = var; | |
6de9cd9a DN |
1011 | |
1012 | /* Substitute operands with their values and try to fold. */ | |
0bca51f0 | 1013 | replace_uses_in (stmt, NULL, const_val); |
5039610b | 1014 | retval = fold_call_expr (rhs, false); |
6de9cd9a DN |
1015 | |
1016 | /* Restore operands to their original form. */ | |
f47c96aa AM |
1017 | i = 0; |
1018 | FOR_EACH_SSA_USE_OPERAND (var_p, stmt, iter, SSA_OP_USE) | |
1019 | SET_USE (var_p, orig[i++]); | |
6de9cd9a DN |
1020 | free (orig); |
1021 | } | |
1022 | } | |
1023 | else | |
1024 | return rhs; | |
1025 | ||
1026 | /* If we got a simplified form, see if we need to convert its type. */ | |
1027 | if (retval) | |
a32e70c3 | 1028 | return fold_convert (TREE_TYPE (rhs), retval); |
6de9cd9a DN |
1029 | |
1030 | /* No simplification was possible. */ | |
1031 | return rhs; | |
1032 | } | |
1033 | ||
1034 | ||
ae3df618 SB |
1035 | /* Return the tree representing the element referenced by T if T is an |
1036 | ARRAY_REF or COMPONENT_REF into constant aggregates. Return | |
1037 | NULL_TREE otherwise. */ | |
1038 | ||
ed97ddc6 | 1039 | tree |
ae3df618 SB |
1040 | fold_const_aggregate_ref (tree t) |
1041 | { | |
1042 | prop_value_t *value; | |
4038c495 GB |
1043 | tree base, ctor, idx, field; |
1044 | unsigned HOST_WIDE_INT cnt; | |
1045 | tree cfield, cval; | |
ae3df618 SB |
1046 | |
1047 | switch (TREE_CODE (t)) | |
1048 | { | |
1049 | case ARRAY_REF: | |
1050 | /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its | |
1051 | DECL_INITIAL. If BASE is a nested reference into another | |
1052 | ARRAY_REF or COMPONENT_REF, make a recursive call to resolve | |
1053 | the inner reference. */ | |
1054 | base = TREE_OPERAND (t, 0); | |
1055 | switch (TREE_CODE (base)) | |
1056 | { | |
1057 | case VAR_DECL: | |
1058 | if (!TREE_READONLY (base) | |
1059 | || TREE_CODE (TREE_TYPE (base)) != ARRAY_TYPE | |
1060 | || !targetm.binds_local_p (base)) | |
1061 | return NULL_TREE; | |
1062 | ||
1063 | ctor = DECL_INITIAL (base); | |
1064 | break; | |
1065 | ||
1066 | case ARRAY_REF: | |
1067 | case COMPONENT_REF: | |
1068 | ctor = fold_const_aggregate_ref (base); | |
1069 | break; | |
1070 | ||
87e1e42b RG |
1071 | case STRING_CST: |
1072 | case CONSTRUCTOR: | |
1073 | ctor = base; | |
1074 | break; | |
1075 | ||
ae3df618 SB |
1076 | default: |
1077 | return NULL_TREE; | |
1078 | } | |
1079 | ||
1080 | if (ctor == NULL_TREE | |
faaf1436 RG |
1081 | || (TREE_CODE (ctor) != CONSTRUCTOR |
1082 | && TREE_CODE (ctor) != STRING_CST) | |
ae3df618 SB |
1083 | || !TREE_STATIC (ctor)) |
1084 | return NULL_TREE; | |
1085 | ||
1086 | /* Get the index. If we have an SSA_NAME, try to resolve it | |
1087 | with the current lattice value for the SSA_NAME. */ | |
1088 | idx = TREE_OPERAND (t, 1); | |
1089 | switch (TREE_CODE (idx)) | |
1090 | { | |
1091 | case SSA_NAME: | |
106dec71 | 1092 | if ((value = get_value (idx)) |
ae3df618 SB |
1093 | && value->lattice_val == CONSTANT |
1094 | && TREE_CODE (value->value) == INTEGER_CST) | |
1095 | idx = value->value; | |
1096 | else | |
1097 | return NULL_TREE; | |
1098 | break; | |
1099 | ||
1100 | case INTEGER_CST: | |
1101 | break; | |
1102 | ||
1103 | default: | |
1104 | return NULL_TREE; | |
1105 | } | |
1106 | ||
faaf1436 RG |
1107 | /* Fold read from constant string. */ |
1108 | if (TREE_CODE (ctor) == STRING_CST) | |
1109 | { | |
1110 | if ((TYPE_MODE (TREE_TYPE (t)) | |
1111 | == TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1112 | && (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1113 | == MODE_INT) | |
1114 | && GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) == 1 | |
1115 | && compare_tree_int (idx, TREE_STRING_LENGTH (ctor)) < 0) | |
0c4d4efb DJ |
1116 | return build_int_cst_type (TREE_TYPE (t), |
1117 | (TREE_STRING_POINTER (ctor) | |
1118 | [TREE_INT_CST_LOW (idx)])); | |
faaf1436 RG |
1119 | return NULL_TREE; |
1120 | } | |
1121 | ||
ae3df618 | 1122 | /* Whoo-hoo! I'll fold ya baby. Yeah! */ |
4038c495 GB |
1123 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) |
1124 | if (tree_int_cst_equal (cfield, idx)) | |
1125 | return cval; | |
ae3df618 SB |
1126 | break; |
1127 | ||
1128 | case COMPONENT_REF: | |
1129 | /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its | |
1130 | DECL_INITIAL. If BASE is a nested reference into another | |
1131 | ARRAY_REF or COMPONENT_REF, make a recursive call to resolve | |
1132 | the inner reference. */ | |
1133 | base = TREE_OPERAND (t, 0); | |
1134 | switch (TREE_CODE (base)) | |
1135 | { | |
1136 | case VAR_DECL: | |
1137 | if (!TREE_READONLY (base) | |
1138 | || TREE_CODE (TREE_TYPE (base)) != RECORD_TYPE | |
1139 | || !targetm.binds_local_p (base)) | |
1140 | return NULL_TREE; | |
1141 | ||
1142 | ctor = DECL_INITIAL (base); | |
1143 | break; | |
1144 | ||
1145 | case ARRAY_REF: | |
1146 | case COMPONENT_REF: | |
1147 | ctor = fold_const_aggregate_ref (base); | |
1148 | break; | |
1149 | ||
1150 | default: | |
1151 | return NULL_TREE; | |
1152 | } | |
1153 | ||
1154 | if (ctor == NULL_TREE | |
1155 | || TREE_CODE (ctor) != CONSTRUCTOR | |
1156 | || !TREE_STATIC (ctor)) | |
1157 | return NULL_TREE; | |
1158 | ||
1159 | field = TREE_OPERAND (t, 1); | |
1160 | ||
4038c495 GB |
1161 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) |
1162 | if (cfield == field | |
ae3df618 | 1163 | /* FIXME: Handle bit-fields. */ |
4038c495 GB |
1164 | && ! DECL_BIT_FIELD (cfield)) |
1165 | return cval; | |
ae3df618 SB |
1166 | break; |
1167 | ||
1ebd8d9a SB |
1168 | case REALPART_EXPR: |
1169 | case IMAGPART_EXPR: | |
1170 | { | |
1171 | tree c = fold_const_aggregate_ref (TREE_OPERAND (t, 0)); | |
1172 | if (c && TREE_CODE (c) == COMPLEX_CST) | |
1173 | return fold_build1 (TREE_CODE (t), TREE_TYPE (t), c); | |
1174 | break; | |
1175 | } | |
87e1e42b RG |
1176 | |
1177 | case INDIRECT_REF: | |
1178 | { | |
1179 | tree base = TREE_OPERAND (t, 0); | |
1180 | if (TREE_CODE (base) == SSA_NAME | |
1181 | && (value = get_value (base)) | |
1182 | && value->lattice_val == CONSTANT | |
1183 | && TREE_CODE (value->value) == ADDR_EXPR) | |
1184 | return fold_const_aggregate_ref (TREE_OPERAND (value->value, 0)); | |
1185 | break; | |
1186 | } | |
1187 | ||
ae3df618 SB |
1188 | default: |
1189 | break; | |
1190 | } | |
1191 | ||
1192 | return NULL_TREE; | |
1193 | } | |
1194 | ||
6de9cd9a DN |
1195 | /* Evaluate statement STMT. */ |
1196 | ||
0bca51f0 | 1197 | static prop_value_t |
6de9cd9a DN |
1198 | evaluate_stmt (tree stmt) |
1199 | { | |
0bca51f0 | 1200 | prop_value_t val; |
faaf1436 | 1201 | tree simplified = NULL_TREE; |
0bca51f0 | 1202 | ccp_lattice_t likelyvalue = likely_value (stmt); |
6ac01510 | 1203 | bool is_constant; |
0bca51f0 DN |
1204 | |
1205 | val.mem_ref = NULL_TREE; | |
6de9cd9a | 1206 | |
6ac01510 ILT |
1207 | fold_defer_overflow_warnings (); |
1208 | ||
6de9cd9a DN |
1209 | /* If the statement is likely to have a CONSTANT result, then try |
1210 | to fold the statement to determine the constant value. */ | |
1211 | if (likelyvalue == CONSTANT) | |
1212 | simplified = ccp_fold (stmt); | |
1213 | /* If the statement is likely to have a VARYING result, then do not | |
1214 | bother folding the statement. */ | |
87e1e42b | 1215 | else if (likelyvalue == VARYING) |
6de9cd9a | 1216 | simplified = get_rhs (stmt); |
6de9cd9a | 1217 | |
6ac01510 ILT |
1218 | is_constant = simplified && is_gimple_min_invariant (simplified); |
1219 | ||
1220 | fold_undefer_overflow_warnings (is_constant, stmt, 0); | |
1221 | ||
1222 | if (is_constant) | |
6de9cd9a DN |
1223 | { |
1224 | /* The statement produced a constant value. */ | |
1225 | val.lattice_val = CONSTANT; | |
0bca51f0 | 1226 | val.value = simplified; |
6de9cd9a DN |
1227 | } |
1228 | else | |
1229 | { | |
1230 | /* The statement produced a nonconstant value. If the statement | |
0bca51f0 DN |
1231 | had UNDEFINED operands, then the result of the statement |
1232 | should be UNDEFINED. Otherwise, the statement is VARYING. */ | |
106dec71 | 1233 | if (likelyvalue == UNDEFINED) |
a318e3ac SB |
1234 | val.lattice_val = likelyvalue; |
1235 | else | |
1236 | val.lattice_val = VARYING; | |
1237 | ||
0bca51f0 | 1238 | val.value = NULL_TREE; |
6de9cd9a | 1239 | } |
750628d8 DN |
1240 | |
1241 | return val; | |
6de9cd9a DN |
1242 | } |
1243 | ||
1244 | ||
750628d8 | 1245 | /* Visit the assignment statement STMT. Set the value of its LHS to the |
0bca51f0 DN |
1246 | value computed by the RHS and store LHS in *OUTPUT_P. If STMT |
1247 | creates virtual definitions, set the value of each new name to that | |
1248 | of the RHS (if we can derive a constant out of the RHS). */ | |
6de9cd9a | 1249 | |
750628d8 DN |
1250 | static enum ssa_prop_result |
1251 | visit_assignment (tree stmt, tree *output_p) | |
6de9cd9a | 1252 | { |
0bca51f0 | 1253 | prop_value_t val; |
750628d8 | 1254 | tree lhs, rhs; |
0bca51f0 | 1255 | enum ssa_prop_result retval; |
6de9cd9a | 1256 | |
07beea0d AH |
1257 | lhs = GIMPLE_STMT_OPERAND (stmt, 0); |
1258 | rhs = GIMPLE_STMT_OPERAND (stmt, 1); | |
6de9cd9a | 1259 | |
750628d8 DN |
1260 | if (TREE_CODE (rhs) == SSA_NAME) |
1261 | { | |
1262 | /* For a simple copy operation, we copy the lattice values. */ | |
106dec71 | 1263 | prop_value_t *nval = get_value (rhs); |
750628d8 DN |
1264 | val = *nval; |
1265 | } | |
0bca51f0 | 1266 | else if (do_store_ccp && stmt_makes_single_load (stmt)) |
750628d8 | 1267 | { |
0bca51f0 | 1268 | /* Same as above, but the RHS is not a gimple register and yet |
106dec71 | 1269 | has a known VUSE. If STMT is loading from the same memory |
0bca51f0 DN |
1270 | location that created the SSA_NAMEs for the virtual operands, |
1271 | we can propagate the value on the RHS. */ | |
1272 | prop_value_t *nval = get_value_loaded_by (stmt, const_val); | |
1273 | ||
106dec71 ZD |
1274 | if (nval |
1275 | && nval->mem_ref | |
a318e3ac | 1276 | && operand_equal_p (nval->mem_ref, rhs, 0)) |
0bca51f0 DN |
1277 | val = *nval; |
1278 | else | |
1279 | val = evaluate_stmt (stmt); | |
750628d8 DN |
1280 | } |
1281 | else | |
9390c347 | 1282 | /* Evaluate the statement. */ |
87e1e42b | 1283 | val = evaluate_stmt (stmt); |
6de9cd9a | 1284 | |
9390c347 | 1285 | /* If the original LHS was a VIEW_CONVERT_EXPR, modify the constant |
ae95537a | 1286 | value to be a VIEW_CONVERT_EXPR of the old constant value. |
9390c347 RK |
1287 | |
1288 | ??? Also, if this was a definition of a bitfield, we need to widen | |
750628d8 DN |
1289 | the constant value into the type of the destination variable. This |
1290 | should not be necessary if GCC represented bitfields properly. */ | |
1291 | { | |
07beea0d | 1292 | tree orig_lhs = GIMPLE_STMT_OPERAND (stmt, 0); |
9390c347 RK |
1293 | |
1294 | if (TREE_CODE (orig_lhs) == VIEW_CONVERT_EXPR | |
1295 | && val.lattice_val == CONSTANT) | |
1296 | { | |
0dd4b47b KH |
1297 | tree w = fold_unary (VIEW_CONVERT_EXPR, |
1298 | TREE_TYPE (TREE_OPERAND (orig_lhs, 0)), | |
1299 | val.value); | |
ae95537a | 1300 | |
3d36fb45 | 1301 | orig_lhs = TREE_OPERAND (orig_lhs, 0); |
ae95537a | 1302 | if (w && is_gimple_min_invariant (w)) |
0bca51f0 | 1303 | val.value = w; |
ae95537a RK |
1304 | else |
1305 | { | |
1306 | val.lattice_val = VARYING; | |
0bca51f0 | 1307 | val.value = NULL; |
ae95537a | 1308 | } |
9390c347 RK |
1309 | } |
1310 | ||
750628d8 | 1311 | if (val.lattice_val == CONSTANT |
9390c347 RK |
1312 | && TREE_CODE (orig_lhs) == COMPONENT_REF |
1313 | && DECL_BIT_FIELD (TREE_OPERAND (orig_lhs, 1))) | |
6de9cd9a | 1314 | { |
0bca51f0 | 1315 | tree w = widen_bitfield (val.value, TREE_OPERAND (orig_lhs, 1), |
9390c347 | 1316 | orig_lhs); |
750628d8 DN |
1317 | |
1318 | if (w && is_gimple_min_invariant (w)) | |
0bca51f0 | 1319 | val.value = w; |
750628d8 | 1320 | else |
6de9cd9a | 1321 | { |
750628d8 | 1322 | val.lattice_val = VARYING; |
0bca51f0 DN |
1323 | val.value = NULL_TREE; |
1324 | val.mem_ref = NULL_TREE; | |
6de9cd9a | 1325 | } |
6de9cd9a | 1326 | } |
750628d8 | 1327 | } |
6de9cd9a | 1328 | |
0bca51f0 | 1329 | retval = SSA_PROP_NOT_INTERESTING; |
6de9cd9a | 1330 | |
750628d8 | 1331 | /* Set the lattice value of the statement's output. */ |
0bca51f0 | 1332 | if (TREE_CODE (lhs) == SSA_NAME) |
6de9cd9a | 1333 | { |
0bca51f0 DN |
1334 | /* If STMT is an assignment to an SSA_NAME, we only have one |
1335 | value to set. */ | |
1336 | if (set_lattice_value (lhs, val)) | |
1337 | { | |
1338 | *output_p = lhs; | |
1339 | if (val.lattice_val == VARYING) | |
1340 | retval = SSA_PROP_VARYING; | |
1341 | else | |
1342 | retval = SSA_PROP_INTERESTING; | |
1343 | } | |
6de9cd9a | 1344 | } |
0bca51f0 DN |
1345 | else if (do_store_ccp && stmt_makes_single_store (stmt)) |
1346 | { | |
38635499 DN |
1347 | /* Otherwise, set the names in VDEF operands to the new |
1348 | constant value and mark the LHS as the memory reference | |
1349 | associated with VAL. */ | |
0bca51f0 DN |
1350 | ssa_op_iter i; |
1351 | tree vdef; | |
1352 | bool changed; | |
1353 | ||
0bca51f0 | 1354 | /* Mark VAL as stored in the LHS of this assignment. */ |
106dec71 ZD |
1355 | if (val.lattice_val == CONSTANT) |
1356 | val.mem_ref = lhs; | |
0bca51f0 DN |
1357 | |
1358 | /* Set the value of every VDEF to VAL. */ | |
1359 | changed = false; | |
1360 | FOR_EACH_SSA_TREE_OPERAND (vdef, stmt, i, SSA_OP_VIRTUAL_DEFS) | |
fc9962ee ZD |
1361 | { |
1362 | /* See PR 29801. We may have VDEFs for read-only variables | |
1363 | (see the handling of unmodifiable variables in | |
1364 | add_virtual_operand); do not attempt to change their value. */ | |
1365 | if (get_symbol_constant_value (SSA_NAME_VAR (vdef)) != NULL_TREE) | |
1366 | continue; | |
1367 | ||
1368 | changed |= set_lattice_value (vdef, val); | |
1369 | } | |
0bca51f0 DN |
1370 | |
1371 | /* Note that for propagation purposes, we are only interested in | |
1372 | visiting statements that load the exact same memory reference | |
1373 | stored here. Those statements will have the exact same list | |
1374 | of virtual uses, so it is enough to set the output of this | |
1375 | statement to be its first virtual definition. */ | |
1376 | *output_p = first_vdef (stmt); | |
1377 | if (changed) | |
1378 | { | |
1379 | if (val.lattice_val == VARYING) | |
1380 | retval = SSA_PROP_VARYING; | |
1381 | else | |
1382 | retval = SSA_PROP_INTERESTING; | |
1383 | } | |
1384 | } | |
1385 | ||
1386 | return retval; | |
6de9cd9a DN |
1387 | } |
1388 | ||
6de9cd9a | 1389 | |
750628d8 DN |
1390 | /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING |
1391 | if it can determine which edge will be taken. Otherwise, return | |
1392 | SSA_PROP_VARYING. */ | |
1393 | ||
1394 | static enum ssa_prop_result | |
1395 | visit_cond_stmt (tree stmt, edge *taken_edge_p) | |
6de9cd9a | 1396 | { |
0bca51f0 | 1397 | prop_value_t val; |
750628d8 DN |
1398 | basic_block block; |
1399 | ||
1400 | block = bb_for_stmt (stmt); | |
1401 | val = evaluate_stmt (stmt); | |
1402 | ||
1403 | /* Find which edge out of the conditional block will be taken and add it | |
1404 | to the worklist. If no single edge can be determined statically, | |
1405 | return SSA_PROP_VARYING to feed all the outgoing edges to the | |
1406 | propagation engine. */ | |
0bca51f0 | 1407 | *taken_edge_p = val.value ? find_taken_edge (block, val.value) : 0; |
750628d8 DN |
1408 | if (*taken_edge_p) |
1409 | return SSA_PROP_INTERESTING; | |
1410 | else | |
1411 | return SSA_PROP_VARYING; | |
6de9cd9a DN |
1412 | } |
1413 | ||
6de9cd9a | 1414 | |
750628d8 DN |
1415 | /* Evaluate statement STMT. If the statement produces an output value and |
1416 | its evaluation changes the lattice value of its output, return | |
1417 | SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the | |
1418 | output value. | |
1419 | ||
1420 | If STMT is a conditional branch and we can determine its truth | |
1421 | value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying | |
1422 | value, return SSA_PROP_VARYING. */ | |
6de9cd9a | 1423 | |
750628d8 DN |
1424 | static enum ssa_prop_result |
1425 | ccp_visit_stmt (tree stmt, edge *taken_edge_p, tree *output_p) | |
1426 | { | |
750628d8 DN |
1427 | tree def; |
1428 | ssa_op_iter iter; | |
6de9cd9a | 1429 | |
750628d8 | 1430 | if (dump_file && (dump_flags & TDF_DETAILS)) |
6de9cd9a | 1431 | { |
0bca51f0 DN |
1432 | fprintf (dump_file, "\nVisiting statement:\n"); |
1433 | print_generic_stmt (dump_file, stmt, dump_flags); | |
750628d8 | 1434 | fprintf (dump_file, "\n"); |
6de9cd9a | 1435 | } |
6de9cd9a | 1436 | |
07beea0d | 1437 | if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT) |
6de9cd9a | 1438 | { |
750628d8 DN |
1439 | /* If the statement is an assignment that produces a single |
1440 | output value, evaluate its RHS to see if the lattice value of | |
1441 | its output has changed. */ | |
1442 | return visit_assignment (stmt, output_p); | |
6de9cd9a | 1443 | } |
750628d8 | 1444 | else if (TREE_CODE (stmt) == COND_EXPR || TREE_CODE (stmt) == SWITCH_EXPR) |
6de9cd9a | 1445 | { |
750628d8 DN |
1446 | /* If STMT is a conditional branch, see if we can determine |
1447 | which branch will be taken. */ | |
1448 | return visit_cond_stmt (stmt, taken_edge_p); | |
6de9cd9a | 1449 | } |
6de9cd9a | 1450 | |
750628d8 DN |
1451 | /* Any other kind of statement is not interesting for constant |
1452 | propagation and, therefore, not worth simulating. */ | |
750628d8 DN |
1453 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1454 | fprintf (dump_file, "No interesting values produced. Marked VARYING.\n"); | |
6de9cd9a | 1455 | |
750628d8 DN |
1456 | /* Definitions made by statements other than assignments to |
1457 | SSA_NAMEs represent unknown modifications to their outputs. | |
1458 | Mark them VARYING. */ | |
0bca51f0 DN |
1459 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) |
1460 | { | |
1461 | prop_value_t v = { VARYING, NULL_TREE, NULL_TREE }; | |
1462 | set_lattice_value (def, v); | |
1463 | } | |
6de9cd9a | 1464 | |
750628d8 DN |
1465 | return SSA_PROP_VARYING; |
1466 | } | |
6de9cd9a | 1467 | |
6de9cd9a | 1468 | |
0bca51f0 | 1469 | /* Main entry point for SSA Conditional Constant Propagation. */ |
750628d8 | 1470 | |
3253eafb | 1471 | static unsigned int |
0bca51f0 | 1472 | execute_ssa_ccp (bool store_ccp) |
750628d8 | 1473 | { |
0bca51f0 | 1474 | do_store_ccp = store_ccp; |
750628d8 DN |
1475 | ccp_initialize (); |
1476 | ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node); | |
3253eafb | 1477 | if (ccp_finalize ()) |
706ca88e | 1478 | return (TODO_cleanup_cfg | TODO_update_ssa | TODO_remove_unused_locals); |
3253eafb JH |
1479 | else |
1480 | return 0; | |
6de9cd9a DN |
1481 | } |
1482 | ||
173b818d | 1483 | |
c2924966 | 1484 | static unsigned int |
0bca51f0 DN |
1485 | do_ssa_ccp (void) |
1486 | { | |
3253eafb | 1487 | return execute_ssa_ccp (false); |
0bca51f0 DN |
1488 | } |
1489 | ||
1490 | ||
173b818d | 1491 | static bool |
750628d8 | 1492 | gate_ccp (void) |
173b818d | 1493 | { |
750628d8 | 1494 | return flag_tree_ccp != 0; |
173b818d BB |
1495 | } |
1496 | ||
6de9cd9a | 1497 | |
8ddbbcae | 1498 | struct gimple_opt_pass pass_ccp = |
750628d8 | 1499 | { |
8ddbbcae JH |
1500 | { |
1501 | GIMPLE_PASS, | |
750628d8 DN |
1502 | "ccp", /* name */ |
1503 | gate_ccp, /* gate */ | |
0bca51f0 | 1504 | do_ssa_ccp, /* execute */ |
750628d8 DN |
1505 | NULL, /* sub */ |
1506 | NULL, /* next */ | |
1507 | 0, /* static_pass_number */ | |
1508 | TV_TREE_CCP, /* tv_id */ | |
7faade0f | 1509 | PROP_cfg | PROP_ssa, /* properties_required */ |
750628d8 | 1510 | 0, /* properties_provided */ |
ae07b463 | 1511 | 0, /* properties_destroyed */ |
750628d8 | 1512 | 0, /* todo_flags_start */ |
3253eafb | 1513 | TODO_dump_func | TODO_verify_ssa |
8ddbbcae JH |
1514 | | TODO_verify_stmts | TODO_ggc_collect/* todo_flags_finish */ |
1515 | } | |
750628d8 | 1516 | }; |
6de9cd9a | 1517 | |
6de9cd9a | 1518 | |
c2924966 | 1519 | static unsigned int |
0bca51f0 DN |
1520 | do_ssa_store_ccp (void) |
1521 | { | |
1522 | /* If STORE-CCP is not enabled, we just run regular CCP. */ | |
3253eafb | 1523 | return execute_ssa_ccp (flag_tree_store_ccp != 0); |
0bca51f0 DN |
1524 | } |
1525 | ||
1526 | static bool | |
1527 | gate_store_ccp (void) | |
1528 | { | |
1529 | /* STORE-CCP is enabled only with -ftree-store-ccp, but when | |
1530 | -fno-tree-store-ccp is specified, we should run regular CCP. | |
1531 | That's why the pass is enabled with either flag. */ | |
1532 | return flag_tree_store_ccp != 0 || flag_tree_ccp != 0; | |
1533 | } | |
1534 | ||
1535 | ||
8ddbbcae | 1536 | struct gimple_opt_pass pass_store_ccp = |
0bca51f0 | 1537 | { |
8ddbbcae JH |
1538 | { |
1539 | GIMPLE_PASS, | |
0bca51f0 DN |
1540 | "store_ccp", /* name */ |
1541 | gate_store_ccp, /* gate */ | |
1542 | do_ssa_store_ccp, /* execute */ | |
1543 | NULL, /* sub */ | |
1544 | NULL, /* next */ | |
1545 | 0, /* static_pass_number */ | |
1546 | TV_TREE_STORE_CCP, /* tv_id */ | |
1547 | PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */ | |
1548 | 0, /* properties_provided */ | |
ae07b463 | 1549 | 0, /* properties_destroyed */ |
0bca51f0 | 1550 | 0, /* todo_flags_start */ |
3253eafb | 1551 | TODO_dump_func | TODO_verify_ssa |
8ddbbcae JH |
1552 | | TODO_verify_stmts | TODO_ggc_collect/* todo_flags_finish */ |
1553 | } | |
0bca51f0 DN |
1554 | }; |
1555 | ||
750628d8 DN |
1556 | /* Given a constant value VAL for bitfield FIELD, and a destination |
1557 | variable VAR, return VAL appropriately widened to fit into VAR. If | |
1558 | FIELD is wider than HOST_WIDE_INT, NULL is returned. */ | |
6de9cd9a | 1559 | |
750628d8 DN |
1560 | tree |
1561 | widen_bitfield (tree val, tree field, tree var) | |
6de9cd9a | 1562 | { |
750628d8 DN |
1563 | unsigned HOST_WIDE_INT var_size, field_size; |
1564 | tree wide_val; | |
1565 | unsigned HOST_WIDE_INT mask; | |
1566 | unsigned int i; | |
6de9cd9a | 1567 | |
750628d8 DN |
1568 | /* We can only do this if the size of the type and field and VAL are |
1569 | all constants representable in HOST_WIDE_INT. */ | |
1570 | if (!host_integerp (TYPE_SIZE (TREE_TYPE (var)), 1) | |
1571 | || !host_integerp (DECL_SIZE (field), 1) | |
1572 | || !host_integerp (val, 0)) | |
1573 | return NULL_TREE; | |
6de9cd9a | 1574 | |
750628d8 DN |
1575 | var_size = tree_low_cst (TYPE_SIZE (TREE_TYPE (var)), 1); |
1576 | field_size = tree_low_cst (DECL_SIZE (field), 1); | |
6de9cd9a | 1577 | |
750628d8 DN |
1578 | /* Give up if either the bitfield or the variable are too wide. */ |
1579 | if (field_size > HOST_BITS_PER_WIDE_INT || var_size > HOST_BITS_PER_WIDE_INT) | |
1580 | return NULL_TREE; | |
6de9cd9a | 1581 | |
1e128c5f | 1582 | gcc_assert (var_size >= field_size); |
6de9cd9a | 1583 | |
750628d8 DN |
1584 | /* If the sign bit of the value is not set or the field's type is unsigned, |
1585 | just mask off the high order bits of the value. */ | |
1586 | if (DECL_UNSIGNED (field) | |
1587 | || !(tree_low_cst (val, 0) & (((HOST_WIDE_INT)1) << (field_size - 1)))) | |
1588 | { | |
1589 | /* Zero extension. Build a mask with the lower 'field_size' bits | |
1590 | set and a BIT_AND_EXPR node to clear the high order bits of | |
1591 | the value. */ | |
1592 | for (i = 0, mask = 0; i < field_size; i++) | |
1593 | mask |= ((HOST_WIDE_INT) 1) << i; | |
6de9cd9a | 1594 | |
f457cf40 JM |
1595 | wide_val = fold_build2 (BIT_AND_EXPR, TREE_TYPE (var), val, |
1596 | build_int_cst (TREE_TYPE (var), mask)); | |
6de9cd9a | 1597 | } |
750628d8 | 1598 | else |
173b818d | 1599 | { |
750628d8 DN |
1600 | /* Sign extension. Create a mask with the upper 'field_size' |
1601 | bits set and a BIT_IOR_EXPR to set the high order bits of the | |
1602 | value. */ | |
1603 | for (i = 0, mask = 0; i < (var_size - field_size); i++) | |
1604 | mask |= ((HOST_WIDE_INT) 1) << (var_size - i - 1); | |
1605 | ||
f457cf40 JM |
1606 | wide_val = fold_build2 (BIT_IOR_EXPR, TREE_TYPE (var), val, |
1607 | build_int_cst (TREE_TYPE (var), mask)); | |
173b818d | 1608 | } |
6de9cd9a | 1609 | |
f457cf40 | 1610 | return wide_val; |
6de9cd9a DN |
1611 | } |
1612 | ||
750628d8 | 1613 | |
6de9cd9a DN |
1614 | /* A subroutine of fold_stmt_r. Attempts to fold *(A+O) to A[X]. |
1615 | BASE is an array type. OFFSET is a byte displacement. ORIG_TYPE | |
9cf737f8 | 1616 | is the desired result type. */ |
6de9cd9a DN |
1617 | |
1618 | static tree | |
1fd89060 RG |
1619 | maybe_fold_offset_to_array_ref (tree base, tree offset, tree orig_type, |
1620 | bool allow_negative_idx) | |
6de9cd9a | 1621 | { |
891fc5e9 | 1622 | tree min_idx, idx, idx_type, elt_offset = integer_zero_node; |
44de5aeb | 1623 | tree array_type, elt_type, elt_size; |
3097760b | 1624 | tree domain_type; |
44de5aeb RK |
1625 | |
1626 | /* If BASE is an ARRAY_REF, we can pick up another offset (this time | |
1627 | measured in units of the size of elements type) from that ARRAY_REF). | |
1628 | We can't do anything if either is variable. | |
1629 | ||
1630 | The case we handle here is *(&A[N]+O). */ | |
1631 | if (TREE_CODE (base) == ARRAY_REF) | |
1632 | { | |
1633 | tree low_bound = array_ref_low_bound (base); | |
1634 | ||
1635 | elt_offset = TREE_OPERAND (base, 1); | |
1636 | if (TREE_CODE (low_bound) != INTEGER_CST | |
1637 | || TREE_CODE (elt_offset) != INTEGER_CST) | |
1638 | return NULL_TREE; | |
1639 | ||
1640 | elt_offset = int_const_binop (MINUS_EXPR, elt_offset, low_bound, 0); | |
1641 | base = TREE_OPERAND (base, 0); | |
1642 | } | |
6de9cd9a DN |
1643 | |
1644 | /* Ignore stupid user tricks of indexing non-array variables. */ | |
1645 | array_type = TREE_TYPE (base); | |
1646 | if (TREE_CODE (array_type) != ARRAY_TYPE) | |
1647 | return NULL_TREE; | |
1648 | elt_type = TREE_TYPE (array_type); | |
f4088621 | 1649 | if (!useless_type_conversion_p (orig_type, elt_type)) |
6de9cd9a | 1650 | return NULL_TREE; |
891fc5e9 RG |
1651 | |
1652 | /* Use signed size type for intermediate computation on the index. */ | |
1653 | idx_type = signed_type_for (size_type_node); | |
1654 | ||
44de5aeb RK |
1655 | /* If OFFSET and ELT_OFFSET are zero, we don't care about the size of the |
1656 | element type (so we can use the alignment if it's not constant). | |
1657 | Otherwise, compute the offset as an index by using a division. If the | |
1658 | division isn't exact, then don't do anything. */ | |
6de9cd9a | 1659 | elt_size = TYPE_SIZE_UNIT (elt_type); |
fe9821b8 JH |
1660 | if (!elt_size) |
1661 | return NULL; | |
44de5aeb RK |
1662 | if (integer_zerop (offset)) |
1663 | { | |
1664 | if (TREE_CODE (elt_size) != INTEGER_CST) | |
1665 | elt_size = size_int (TYPE_ALIGN (elt_type)); | |
6de9cd9a | 1666 | |
891fc5e9 | 1667 | idx = build_int_cst (idx_type, 0); |
44de5aeb RK |
1668 | } |
1669 | else | |
1670 | { | |
1671 | unsigned HOST_WIDE_INT lquo, lrem; | |
1672 | HOST_WIDE_INT hquo, hrem; | |
891fc5e9 | 1673 | double_int soffset; |
44de5aeb | 1674 | |
891fc5e9 RG |
1675 | /* The final array offset should be signed, so we need |
1676 | to sign-extend the (possibly pointer) offset here | |
1677 | and use signed division. */ | |
1678 | soffset = double_int_sext (tree_to_double_int (offset), | |
1679 | TYPE_PRECISION (TREE_TYPE (offset))); | |
44de5aeb | 1680 | if (TREE_CODE (elt_size) != INTEGER_CST |
891fc5e9 RG |
1681 | || div_and_round_double (TRUNC_DIV_EXPR, 0, |
1682 | soffset.low, soffset.high, | |
44de5aeb RK |
1683 | TREE_INT_CST_LOW (elt_size), |
1684 | TREE_INT_CST_HIGH (elt_size), | |
1685 | &lquo, &hquo, &lrem, &hrem) | |
1686 | || lrem || hrem) | |
1687 | return NULL_TREE; | |
6de9cd9a | 1688 | |
891fc5e9 | 1689 | idx = build_int_cst_wide (idx_type, lquo, hquo); |
44de5aeb RK |
1690 | } |
1691 | ||
1692 | /* Assume the low bound is zero. If there is a domain type, get the | |
1693 | low bound, if any, convert the index into that type, and add the | |
1694 | low bound. */ | |
891fc5e9 | 1695 | min_idx = build_int_cst (idx_type, 0); |
3097760b JH |
1696 | domain_type = TYPE_DOMAIN (array_type); |
1697 | if (domain_type) | |
6de9cd9a | 1698 | { |
3097760b | 1699 | idx_type = domain_type; |
891fc5e9 RG |
1700 | if (TYPE_MIN_VALUE (idx_type)) |
1701 | min_idx = TYPE_MIN_VALUE (idx_type); | |
44de5aeb | 1702 | else |
891fc5e9 | 1703 | min_idx = fold_convert (idx_type, min_idx); |
44de5aeb RK |
1704 | |
1705 | if (TREE_CODE (min_idx) != INTEGER_CST) | |
1706 | return NULL_TREE; | |
1707 | ||
891fc5e9 | 1708 | elt_offset = fold_convert (idx_type, elt_offset); |
6de9cd9a DN |
1709 | } |
1710 | ||
44de5aeb RK |
1711 | if (!integer_zerop (min_idx)) |
1712 | idx = int_const_binop (PLUS_EXPR, idx, min_idx, 0); | |
1713 | if (!integer_zerop (elt_offset)) | |
1714 | idx = int_const_binop (PLUS_EXPR, idx, elt_offset, 0); | |
1715 | ||
891fc5e9 RG |
1716 | /* Make sure to possibly truncate late after offsetting. */ |
1717 | idx = fold_convert (idx_type, idx); | |
1718 | ||
3097760b | 1719 | /* We don't want to construct access past array bounds. For example |
1fd89060 RG |
1720 | char *(c[4]); |
1721 | c[3][2]; | |
1722 | should not be simplified into (*c)[14] or tree-vrp will | |
1723 | give false warnings. The same is true for | |
1724 | struct A { long x; char d[0]; } *a; | |
1725 | (char *)a - 4; | |
1726 | which should be not folded to &a->d[-8]. */ | |
1727 | if (domain_type | |
1728 | && TYPE_MAX_VALUE (domain_type) | |
3097760b JH |
1729 | && TREE_CODE (TYPE_MAX_VALUE (domain_type)) == INTEGER_CST) |
1730 | { | |
1731 | tree up_bound = TYPE_MAX_VALUE (domain_type); | |
1732 | ||
1733 | if (tree_int_cst_lt (up_bound, idx) | |
1734 | /* Accesses after the end of arrays of size 0 (gcc | |
1735 | extension) and 1 are likely intentional ("struct | |
1736 | hack"). */ | |
1737 | && compare_tree_int (up_bound, 1) > 0) | |
1738 | return NULL_TREE; | |
1739 | } | |
1fd89060 RG |
1740 | if (domain_type |
1741 | && TYPE_MIN_VALUE (domain_type)) | |
1742 | { | |
1743 | if (!allow_negative_idx | |
1744 | && TREE_CODE (TYPE_MIN_VALUE (domain_type)) == INTEGER_CST | |
1745 | && tree_int_cst_lt (idx, TYPE_MIN_VALUE (domain_type))) | |
1746 | return NULL_TREE; | |
1747 | } | |
1748 | else if (!allow_negative_idx | |
1749 | && compare_tree_int (idx, 0) < 0) | |
1750 | return NULL_TREE; | |
3097760b | 1751 | |
04d86531 | 1752 | return build4 (ARRAY_REF, elt_type, base, idx, NULL_TREE, NULL_TREE); |
6de9cd9a DN |
1753 | } |
1754 | ||
750628d8 | 1755 | |
fe9821b8 | 1756 | /* Attempt to fold *(S+O) to S.X. |
6de9cd9a DN |
1757 | BASE is a record type. OFFSET is a byte displacement. ORIG_TYPE |
1758 | is the desired result type. */ | |
6de9cd9a | 1759 | |
fe9821b8 | 1760 | static tree |
6de9cd9a DN |
1761 | maybe_fold_offset_to_component_ref (tree record_type, tree base, tree offset, |
1762 | tree orig_type, bool base_is_ptr) | |
1763 | { | |
f34fa464 | 1764 | tree f, t, field_type, tail_array_field, field_offset; |
6e6e19cb JH |
1765 | tree ret; |
1766 | tree new_base; | |
6de9cd9a DN |
1767 | |
1768 | if (TREE_CODE (record_type) != RECORD_TYPE | |
1769 | && TREE_CODE (record_type) != UNION_TYPE | |
1770 | && TREE_CODE (record_type) != QUAL_UNION_TYPE) | |
1771 | return NULL_TREE; | |
1772 | ||
1773 | /* Short-circuit silly cases. */ | |
f4088621 | 1774 | if (useless_type_conversion_p (record_type, orig_type)) |
6de9cd9a DN |
1775 | return NULL_TREE; |
1776 | ||
1777 | tail_array_field = NULL_TREE; | |
1778 | for (f = TYPE_FIELDS (record_type); f ; f = TREE_CHAIN (f)) | |
1779 | { | |
1780 | int cmp; | |
1781 | ||
1782 | if (TREE_CODE (f) != FIELD_DECL) | |
1783 | continue; | |
1784 | if (DECL_BIT_FIELD (f)) | |
1785 | continue; | |
f34fa464 | 1786 | |
fe9821b8 JH |
1787 | if (!DECL_FIELD_OFFSET (f)) |
1788 | continue; | |
f34fa464 ZD |
1789 | field_offset = byte_position (f); |
1790 | if (TREE_CODE (field_offset) != INTEGER_CST) | |
6de9cd9a DN |
1791 | continue; |
1792 | ||
1793 | /* ??? Java creates "interesting" fields for representing base classes. | |
1794 | They have no name, and have no context. With no context, we get into | |
1795 | trouble with nonoverlapping_component_refs_p. Skip them. */ | |
1796 | if (!DECL_FIELD_CONTEXT (f)) | |
1797 | continue; | |
1798 | ||
1799 | /* The previous array field isn't at the end. */ | |
1800 | tail_array_field = NULL_TREE; | |
1801 | ||
1802 | /* Check to see if this offset overlaps with the field. */ | |
f34fa464 | 1803 | cmp = tree_int_cst_compare (field_offset, offset); |
6de9cd9a DN |
1804 | if (cmp > 0) |
1805 | continue; | |
1806 | ||
1807 | field_type = TREE_TYPE (f); | |
6de9cd9a DN |
1808 | |
1809 | /* Here we exactly match the offset being checked. If the types match, | |
1810 | then we can return that field. */ | |
53dba802 | 1811 | if (cmp == 0 |
f4088621 | 1812 | && useless_type_conversion_p (orig_type, field_type)) |
6de9cd9a DN |
1813 | { |
1814 | if (base_is_ptr) | |
1815 | base = build1 (INDIRECT_REF, record_type, base); | |
b4257cfc | 1816 | t = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE); |
6de9cd9a DN |
1817 | return t; |
1818 | } | |
53dba802 ZD |
1819 | |
1820 | /* Don't care about offsets into the middle of scalars. */ | |
1821 | if (!AGGREGATE_TYPE_P (field_type)) | |
1822 | continue; | |
6de9cd9a | 1823 | |
53dba802 ZD |
1824 | /* Check for array at the end of the struct. This is often |
1825 | used as for flexible array members. We should be able to | |
1826 | turn this into an array access anyway. */ | |
1827 | if (TREE_CODE (field_type) == ARRAY_TYPE) | |
1828 | tail_array_field = f; | |
1829 | ||
1830 | /* Check the end of the field against the offset. */ | |
1831 | if (!DECL_SIZE_UNIT (f) | |
1832 | || TREE_CODE (DECL_SIZE_UNIT (f)) != INTEGER_CST) | |
1833 | continue; | |
1834 | t = int_const_binop (MINUS_EXPR, offset, field_offset, 1); | |
1835 | if (!tree_int_cst_lt (t, DECL_SIZE_UNIT (f))) | |
1836 | continue; | |
6de9cd9a | 1837 | |
53dba802 ZD |
1838 | /* If we matched, then set offset to the displacement into |
1839 | this field. */ | |
6e6e19cb JH |
1840 | if (base_is_ptr) |
1841 | new_base = build1 (INDIRECT_REF, record_type, base); | |
1842 | else | |
1843 | new_base = base; | |
1844 | new_base = build3 (COMPONENT_REF, field_type, new_base, f, NULL_TREE); | |
1845 | ||
1846 | /* Recurse to possibly find the match. */ | |
1fd89060 RG |
1847 | ret = maybe_fold_offset_to_array_ref (new_base, t, orig_type, |
1848 | f == TYPE_FIELDS (record_type)); | |
6e6e19cb JH |
1849 | if (ret) |
1850 | return ret; | |
1851 | ret = maybe_fold_offset_to_component_ref (field_type, new_base, t, | |
1852 | orig_type, false); | |
1853 | if (ret) | |
1854 | return ret; | |
6de9cd9a DN |
1855 | } |
1856 | ||
1857 | if (!tail_array_field) | |
1858 | return NULL_TREE; | |
1859 | ||
1860 | f = tail_array_field; | |
1861 | field_type = TREE_TYPE (f); | |
53dba802 | 1862 | offset = int_const_binop (MINUS_EXPR, offset, byte_position (f), 1); |
6de9cd9a | 1863 | |
6de9cd9a | 1864 | /* If we get here, we've got an aggregate field, and a possibly |
1ea7e6ad | 1865 | nonzero offset into them. Recurse and hope for a valid match. */ |
6de9cd9a DN |
1866 | if (base_is_ptr) |
1867 | base = build1 (INDIRECT_REF, record_type, base); | |
b4257cfc | 1868 | base = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE); |
6de9cd9a | 1869 | |
1fd89060 RG |
1870 | t = maybe_fold_offset_to_array_ref (base, offset, orig_type, |
1871 | f == TYPE_FIELDS (record_type)); | |
6de9cd9a DN |
1872 | if (t) |
1873 | return t; | |
1874 | return maybe_fold_offset_to_component_ref (field_type, base, offset, | |
1875 | orig_type, false); | |
1876 | } | |
1877 | ||
fe9821b8 JH |
1878 | /* Attempt to express (ORIG_TYPE)BASE+OFFSET as BASE->field_of_orig_type |
1879 | or BASE[index] or by combination of those. | |
1880 | ||
1881 | Before attempting the conversion strip off existing ADDR_EXPRs and | |
1882 | handled component refs. */ | |
1883 | ||
1884 | tree | |
1885 | maybe_fold_offset_to_reference (tree base, tree offset, tree orig_type) | |
1886 | { | |
1887 | tree ret; | |
1888 | tree type; | |
1889 | bool base_is_ptr = true; | |
1890 | ||
1891 | STRIP_NOPS (base); | |
1892 | if (TREE_CODE (base) == ADDR_EXPR) | |
1893 | { | |
1894 | base_is_ptr = false; | |
1895 | ||
1896 | base = TREE_OPERAND (base, 0); | |
1897 | ||
1898 | /* Handle case where existing COMPONENT_REF pick e.g. wrong field of union, | |
1899 | so it needs to be removed and new COMPONENT_REF constructed. | |
1900 | The wrong COMPONENT_REF are often constructed by folding the | |
1901 | (type *)&object within the expression (type *)&object+offset */ | |
1902 | if (handled_component_p (base) && 0) | |
1903 | { | |
1904 | HOST_WIDE_INT sub_offset, size, maxsize; | |
1905 | tree newbase; | |
1906 | newbase = get_ref_base_and_extent (base, &sub_offset, | |
1907 | &size, &maxsize); | |
1908 | gcc_assert (newbase); | |
1909 | gcc_assert (!(sub_offset & (BITS_PER_UNIT - 1))); | |
1910 | if (size == maxsize) | |
1911 | { | |
1912 | base = newbase; | |
1913 | if (sub_offset) | |
1914 | offset = int_const_binop (PLUS_EXPR, offset, | |
1915 | build_int_cst (TREE_TYPE (offset), | |
1916 | sub_offset / BITS_PER_UNIT), 1); | |
1917 | } | |
1918 | } | |
f4088621 | 1919 | if (useless_type_conversion_p (orig_type, TREE_TYPE (base)) |
fe9821b8 JH |
1920 | && integer_zerop (offset)) |
1921 | return base; | |
1922 | type = TREE_TYPE (base); | |
1923 | } | |
1924 | else | |
1925 | { | |
1926 | base_is_ptr = true; | |
1927 | if (!POINTER_TYPE_P (TREE_TYPE (base))) | |
1928 | return NULL_TREE; | |
1929 | type = TREE_TYPE (TREE_TYPE (base)); | |
1930 | } | |
1931 | ret = maybe_fold_offset_to_component_ref (type, base, offset, | |
1932 | orig_type, base_is_ptr); | |
1933 | if (!ret) | |
1934 | { | |
1935 | if (base_is_ptr) | |
1936 | base = build1 (INDIRECT_REF, type, base); | |
1fd89060 | 1937 | ret = maybe_fold_offset_to_array_ref (base, offset, orig_type, true); |
fe9821b8 JH |
1938 | } |
1939 | return ret; | |
1940 | } | |
750628d8 | 1941 | |
6de9cd9a DN |
1942 | /* A subroutine of fold_stmt_r. Attempt to simplify *(BASE+OFFSET). |
1943 | Return the simplified expression, or NULL if nothing could be done. */ | |
1944 | ||
1945 | static tree | |
1946 | maybe_fold_stmt_indirect (tree expr, tree base, tree offset) | |
1947 | { | |
1948 | tree t; | |
cbf8d355 | 1949 | bool volatile_p = TREE_THIS_VOLATILE (expr); |
6de9cd9a DN |
1950 | |
1951 | /* We may well have constructed a double-nested PLUS_EXPR via multiple | |
1952 | substitutions. Fold that down to one. Remove NON_LVALUE_EXPRs that | |
1953 | are sometimes added. */ | |
1954 | base = fold (base); | |
ff7c8597 | 1955 | STRIP_TYPE_NOPS (base); |
6de9cd9a DN |
1956 | TREE_OPERAND (expr, 0) = base; |
1957 | ||
1958 | /* One possibility is that the address reduces to a string constant. */ | |
1959 | t = fold_read_from_constant_string (expr); | |
1960 | if (t) | |
1961 | return t; | |
1962 | ||
5be014d5 AP |
1963 | /* Add in any offset from a POINTER_PLUS_EXPR. */ |
1964 | if (TREE_CODE (base) == POINTER_PLUS_EXPR) | |
6de9cd9a DN |
1965 | { |
1966 | tree offset2; | |
1967 | ||
1968 | offset2 = TREE_OPERAND (base, 1); | |
1969 | if (TREE_CODE (offset2) != INTEGER_CST) | |
1970 | return NULL_TREE; | |
1971 | base = TREE_OPERAND (base, 0); | |
1972 | ||
5be014d5 AP |
1973 | offset = fold_convert (sizetype, |
1974 | int_const_binop (PLUS_EXPR, offset, offset2, 1)); | |
6de9cd9a DN |
1975 | } |
1976 | ||
1977 | if (TREE_CODE (base) == ADDR_EXPR) | |
1978 | { | |
fe9821b8 JH |
1979 | tree base_addr = base; |
1980 | ||
6de9cd9a DN |
1981 | /* Strip the ADDR_EXPR. */ |
1982 | base = TREE_OPERAND (base, 0); | |
1983 | ||
0534fa56 RH |
1984 | /* Fold away CONST_DECL to its value, if the type is scalar. */ |
1985 | if (TREE_CODE (base) == CONST_DECL | |
688e936d | 1986 | && ccp_decl_initial_min_invariant (DECL_INITIAL (base))) |
0534fa56 RH |
1987 | return DECL_INITIAL (base); |
1988 | ||
6de9cd9a | 1989 | /* Try folding *(&B+O) to B.X. */ |
fe9821b8 JH |
1990 | t = maybe_fold_offset_to_reference (base_addr, offset, |
1991 | TREE_TYPE (expr)); | |
6de9cd9a | 1992 | if (t) |
cbf8d355 RG |
1993 | { |
1994 | TREE_THIS_VOLATILE (t) = volatile_p; | |
1995 | return t; | |
1996 | } | |
6de9cd9a DN |
1997 | } |
1998 | else | |
1999 | { | |
2000 | /* We can get here for out-of-range string constant accesses, | |
2001 | such as "_"[3]. Bail out of the entire substitution search | |
2002 | and arrange for the entire statement to be replaced by a | |
aabcd309 | 2003 | call to __builtin_trap. In all likelihood this will all be |
6de9cd9a DN |
2004 | constant-folded away, but in the meantime we can't leave with |
2005 | something that get_expr_operands can't understand. */ | |
2006 | ||
2007 | t = base; | |
2008 | STRIP_NOPS (t); | |
2009 | if (TREE_CODE (t) == ADDR_EXPR | |
2010 | && TREE_CODE (TREE_OPERAND (t, 0)) == STRING_CST) | |
2011 | { | |
2012 | /* FIXME: Except that this causes problems elsewhere with dead | |
0e61db61 | 2013 | code not being deleted, and we die in the rtl expanders |
6de9cd9a DN |
2014 | because we failed to remove some ssa_name. In the meantime, |
2015 | just return zero. */ | |
2016 | /* FIXME2: This condition should be signaled by | |
2017 | fold_read_from_constant_string directly, rather than | |
2018 | re-checking for it here. */ | |
2019 | return integer_zero_node; | |
2020 | } | |
2021 | ||
2022 | /* Try folding *(B+O) to B->X. Still an improvement. */ | |
2023 | if (POINTER_TYPE_P (TREE_TYPE (base))) | |
2024 | { | |
fe9821b8 JH |
2025 | t = maybe_fold_offset_to_reference (base, offset, |
2026 | TREE_TYPE (expr)); | |
6de9cd9a DN |
2027 | if (t) |
2028 | return t; | |
2029 | } | |
2030 | } | |
2031 | ||
2032 | /* Otherwise we had an offset that we could not simplify. */ | |
2033 | return NULL_TREE; | |
2034 | } | |
2035 | ||
750628d8 | 2036 | |
5be014d5 | 2037 | /* A subroutine of fold_stmt_r. EXPR is a POINTER_PLUS_EXPR. |
6de9cd9a DN |
2038 | |
2039 | A quaint feature extant in our address arithmetic is that there | |
2040 | can be hidden type changes here. The type of the result need | |
2041 | not be the same as the type of the input pointer. | |
2042 | ||
2043 | What we're after here is an expression of the form | |
2044 | (T *)(&array + const) | |
2045 | where the cast doesn't actually exist, but is implicit in the | |
5be014d5 | 2046 | type of the POINTER_PLUS_EXPR. We'd like to turn this into |
6de9cd9a DN |
2047 | &array[x] |
2048 | which may be able to propagate further. */ | |
2049 | ||
2050 | static tree | |
2051 | maybe_fold_stmt_addition (tree expr) | |
2052 | { | |
2053 | tree op0 = TREE_OPERAND (expr, 0); | |
2054 | tree op1 = TREE_OPERAND (expr, 1); | |
2055 | tree ptr_type = TREE_TYPE (expr); | |
2056 | tree ptd_type; | |
2057 | tree t; | |
6de9cd9a | 2058 | |
5be014d5 AP |
2059 | gcc_assert (TREE_CODE (expr) == POINTER_PLUS_EXPR); |
2060 | ||
6de9cd9a DN |
2061 | /* It had better be a constant. */ |
2062 | if (TREE_CODE (op1) != INTEGER_CST) | |
2063 | return NULL_TREE; | |
2064 | /* The first operand should be an ADDR_EXPR. */ | |
2065 | if (TREE_CODE (op0) != ADDR_EXPR) | |
2066 | return NULL_TREE; | |
2067 | op0 = TREE_OPERAND (op0, 0); | |
2068 | ||
2069 | /* If the first operand is an ARRAY_REF, expand it so that we can fold | |
2070 | the offset into it. */ | |
2071 | while (TREE_CODE (op0) == ARRAY_REF) | |
2072 | { | |
2073 | tree array_obj = TREE_OPERAND (op0, 0); | |
2074 | tree array_idx = TREE_OPERAND (op0, 1); | |
2075 | tree elt_type = TREE_TYPE (op0); | |
2076 | tree elt_size = TYPE_SIZE_UNIT (elt_type); | |
2077 | tree min_idx; | |
2078 | ||
2079 | if (TREE_CODE (array_idx) != INTEGER_CST) | |
2080 | break; | |
2081 | if (TREE_CODE (elt_size) != INTEGER_CST) | |
2082 | break; | |
2083 | ||
2084 | /* Un-bias the index by the min index of the array type. */ | |
2085 | min_idx = TYPE_DOMAIN (TREE_TYPE (array_obj)); | |
2086 | if (min_idx) | |
2087 | { | |
2088 | min_idx = TYPE_MIN_VALUE (min_idx); | |
2089 | if (min_idx) | |
2090 | { | |
44de5aeb RK |
2091 | if (TREE_CODE (min_idx) != INTEGER_CST) |
2092 | break; | |
2093 | ||
b6f65e3c | 2094 | array_idx = fold_convert (TREE_TYPE (min_idx), array_idx); |
6de9cd9a DN |
2095 | if (!integer_zerop (min_idx)) |
2096 | array_idx = int_const_binop (MINUS_EXPR, array_idx, | |
2097 | min_idx, 0); | |
2098 | } | |
2099 | } | |
2100 | ||
2101 | /* Convert the index to a byte offset. */ | |
b6f65e3c | 2102 | array_idx = fold_convert (sizetype, array_idx); |
6de9cd9a DN |
2103 | array_idx = int_const_binop (MULT_EXPR, array_idx, elt_size, 0); |
2104 | ||
2105 | /* Update the operands for the next round, or for folding. */ | |
5be014d5 | 2106 | op1 = int_const_binop (PLUS_EXPR, |
6de9cd9a | 2107 | array_idx, op1, 0); |
6de9cd9a DN |
2108 | op0 = array_obj; |
2109 | } | |
2110 | ||
6de9cd9a | 2111 | ptd_type = TREE_TYPE (ptr_type); |
c4e5b5a8 RG |
2112 | /* If we want a pointer to void, reconstruct the reference from the |
2113 | array element type. A pointer to that can be trivially converted | |
2114 | to void *. This happens as we fold (void *)(ptr p+ off). */ | |
2115 | if (VOID_TYPE_P (ptd_type) | |
2116 | && TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE) | |
2117 | ptd_type = TREE_TYPE (TREE_TYPE (op0)); | |
6de9cd9a DN |
2118 | |
2119 | /* At which point we can try some of the same things as for indirects. */ | |
1fd89060 | 2120 | t = maybe_fold_offset_to_array_ref (op0, op1, ptd_type, true); |
6de9cd9a DN |
2121 | if (!t) |
2122 | t = maybe_fold_offset_to_component_ref (TREE_TYPE (op0), op0, op1, | |
2123 | ptd_type, false); | |
2124 | if (t) | |
2125 | t = build1 (ADDR_EXPR, ptr_type, t); | |
2126 | ||
2127 | return t; | |
2128 | } | |
2129 | ||
622f91ba JL |
2130 | /* For passing state through walk_tree into fold_stmt_r and its |
2131 | children. */ | |
2132 | ||
2133 | struct fold_stmt_r_data | |
2134 | { | |
6ac01510 ILT |
2135 | tree stmt; |
2136 | bool *changed_p; | |
2137 | bool *inside_addr_expr_p; | |
622f91ba JL |
2138 | }; |
2139 | ||
6de9cd9a DN |
2140 | /* Subroutine of fold_stmt called via walk_tree. We perform several |
2141 | simplifications of EXPR_P, mostly having to do with pointer arithmetic. */ | |
2142 | ||
2143 | static tree | |
2144 | fold_stmt_r (tree *expr_p, int *walk_subtrees, void *data) | |
2145 | { | |
858904db | 2146 | struct fold_stmt_r_data *fold_stmt_r_data = (struct fold_stmt_r_data *) data; |
622f91ba JL |
2147 | bool *inside_addr_expr_p = fold_stmt_r_data->inside_addr_expr_p; |
2148 | bool *changed_p = fold_stmt_r_data->changed_p; | |
6de9cd9a | 2149 | tree expr = *expr_p, t; |
6aaa4013 | 2150 | bool volatile_p = TREE_THIS_VOLATILE (expr); |
6de9cd9a DN |
2151 | |
2152 | /* ??? It'd be nice if walk_tree had a pre-order option. */ | |
2153 | switch (TREE_CODE (expr)) | |
2154 | { | |
2155 | case INDIRECT_REF: | |
2156 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
2157 | if (t) | |
2158 | return t; | |
2159 | *walk_subtrees = 0; | |
2160 | ||
2161 | t = maybe_fold_stmt_indirect (expr, TREE_OPERAND (expr, 0), | |
2162 | integer_zero_node); | |
2163 | break; | |
2164 | ||
fe9821b8 JH |
2165 | case NOP_EXPR: |
2166 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
2167 | if (t) | |
2168 | return t; | |
2169 | *walk_subtrees = 0; | |
2170 | ||
2171 | if (POINTER_TYPE_P (TREE_TYPE (expr)) | |
2172 | && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0))) | |
2173 | && (t = maybe_fold_offset_to_reference | |
2174 | (TREE_OPERAND (expr, 0), | |
2175 | integer_zero_node, | |
2176 | TREE_TYPE (TREE_TYPE (expr))))) | |
fa2050d2 RG |
2177 | { |
2178 | tree ptr_type = build_pointer_type (TREE_TYPE (t)); | |
2179 | if (!useless_type_conversion_p (TREE_TYPE (expr), ptr_type)) | |
2180 | return NULL_TREE; | |
2181 | t = build_fold_addr_expr_with_type (t, ptr_type); | |
2182 | } | |
fe9821b8 JH |
2183 | break; |
2184 | ||
622f91ba | 2185 | /* ??? Could handle more ARRAY_REFs here, as a variant of INDIRECT_REF. |
6de9cd9a DN |
2186 | We'd only want to bother decomposing an existing ARRAY_REF if |
2187 | the base array is found to have another offset contained within. | |
2188 | Otherwise we'd be wasting time. */ | |
622f91ba JL |
2189 | case ARRAY_REF: |
2190 | /* If we are not processing expressions found within an | |
2191 | ADDR_EXPR, then we can fold constant array references. */ | |
2192 | if (!*inside_addr_expr_p) | |
2193 | t = fold_read_from_constant_string (expr); | |
2194 | else | |
2195 | t = NULL; | |
2196 | break; | |
6de9cd9a DN |
2197 | |
2198 | case ADDR_EXPR: | |
622f91ba | 2199 | *inside_addr_expr_p = true; |
6de9cd9a | 2200 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); |
622f91ba | 2201 | *inside_addr_expr_p = false; |
6de9cd9a DN |
2202 | if (t) |
2203 | return t; | |
2204 | *walk_subtrees = 0; | |
2205 | ||
2206 | /* Set TREE_INVARIANT properly so that the value is properly | |
2207 | considered constant, and so gets propagated as expected. */ | |
2208 | if (*changed_p) | |
127203ac | 2209 | recompute_tree_invariant_for_addr_expr (expr); |
6de9cd9a DN |
2210 | return NULL_TREE; |
2211 | ||
5be014d5 | 2212 | case POINTER_PLUS_EXPR: |
6de9cd9a DN |
2213 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); |
2214 | if (t) | |
2215 | return t; | |
2216 | t = walk_tree (&TREE_OPERAND (expr, 1), fold_stmt_r, data, NULL); | |
2217 | if (t) | |
2218 | return t; | |
2219 | *walk_subtrees = 0; | |
2220 | ||
2221 | t = maybe_fold_stmt_addition (expr); | |
2222 | break; | |
2223 | ||
2224 | case COMPONENT_REF: | |
2225 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
2226 | if (t) | |
2227 | return t; | |
2228 | *walk_subtrees = 0; | |
2229 | ||
fa27426e RH |
2230 | /* Make sure the FIELD_DECL is actually a field in the type on the lhs. |
2231 | We've already checked that the records are compatible, so we should | |
2232 | come up with a set of compatible fields. */ | |
2233 | { | |
2234 | tree expr_record = TREE_TYPE (TREE_OPERAND (expr, 0)); | |
2235 | tree expr_field = TREE_OPERAND (expr, 1); | |
2236 | ||
2237 | if (DECL_FIELD_CONTEXT (expr_field) != TYPE_MAIN_VARIANT (expr_record)) | |
2238 | { | |
2239 | expr_field = find_compatible_field (expr_record, expr_field); | |
2240 | TREE_OPERAND (expr, 1) = expr_field; | |
2241 | } | |
2242 | } | |
6de9cd9a DN |
2243 | break; |
2244 | ||
ac182688 ZD |
2245 | case TARGET_MEM_REF: |
2246 | t = maybe_fold_tmr (expr); | |
2247 | break; | |
2248 | ||
f393e7f5 RG |
2249 | case COND_EXPR: |
2250 | if (COMPARISON_CLASS_P (TREE_OPERAND (expr, 0))) | |
2251 | { | |
2252 | tree op0 = TREE_OPERAND (expr, 0); | |
6ac01510 ILT |
2253 | tree tem; |
2254 | bool set; | |
2255 | ||
2256 | fold_defer_overflow_warnings (); | |
2257 | tem = fold_binary (TREE_CODE (op0), TREE_TYPE (op0), | |
2258 | TREE_OPERAND (op0, 0), | |
2259 | TREE_OPERAND (op0, 1)); | |
2260 | set = tem && set_rhs (expr_p, tem); | |
2261 | fold_undefer_overflow_warnings (set, fold_stmt_r_data->stmt, 0); | |
2262 | if (set) | |
5cdc4a26 RS |
2263 | { |
2264 | t = *expr_p; | |
2265 | break; | |
2266 | } | |
f393e7f5 | 2267 | } |
5cdc4a26 | 2268 | return NULL_TREE; |
f393e7f5 | 2269 | |
6de9cd9a DN |
2270 | default: |
2271 | return NULL_TREE; | |
2272 | } | |
2273 | ||
2274 | if (t) | |
2275 | { | |
6aaa4013 RG |
2276 | /* Preserve volatileness of the original expression. */ |
2277 | TREE_THIS_VOLATILE (t) = volatile_p; | |
6de9cd9a DN |
2278 | *expr_p = t; |
2279 | *changed_p = true; | |
2280 | } | |
2281 | ||
2282 | return NULL_TREE; | |
2283 | } | |
2284 | ||
6de9cd9a | 2285 | |
10a0d495 JJ |
2286 | /* Return the string length, maximum string length or maximum value of |
2287 | ARG in LENGTH. | |
2288 | If ARG is an SSA name variable, follow its use-def chains. If LENGTH | |
2289 | is not NULL and, for TYPE == 0, its value is not equal to the length | |
2290 | we determine or if we are unable to determine the length or value, | |
2291 | return false. VISITED is a bitmap of visited variables. | |
2292 | TYPE is 0 if string length should be returned, 1 for maximum string | |
2293 | length and 2 for maximum value ARG can have. */ | |
6de9cd9a | 2294 | |
06a9b53f | 2295 | static bool |
10a0d495 | 2296 | get_maxval_strlen (tree arg, tree *length, bitmap visited, int type) |
6de9cd9a | 2297 | { |
750628d8 DN |
2298 | tree var, def_stmt, val; |
2299 | ||
2300 | if (TREE_CODE (arg) != SSA_NAME) | |
06a9b53f | 2301 | { |
f255541f RC |
2302 | if (TREE_CODE (arg) == COND_EXPR) |
2303 | return get_maxval_strlen (COND_EXPR_THEN (arg), length, visited, type) | |
2304 | && get_maxval_strlen (COND_EXPR_ELSE (arg), length, visited, type); | |
c4e5b5a8 RG |
2305 | /* We can end up with &(*iftmp_1)[0] here as well, so handle it. */ |
2306 | else if (TREE_CODE (arg) == ADDR_EXPR | |
2307 | && TREE_CODE (TREE_OPERAND (arg, 0)) == ARRAY_REF | |
2308 | && integer_zerop (TREE_OPERAND (TREE_OPERAND (arg, 0), 1))) | |
2309 | { | |
2310 | tree aop0 = TREE_OPERAND (TREE_OPERAND (arg, 0), 0); | |
2311 | if (TREE_CODE (aop0) == INDIRECT_REF | |
2312 | && TREE_CODE (TREE_OPERAND (aop0, 0)) == SSA_NAME) | |
2313 | return get_maxval_strlen (TREE_OPERAND (aop0, 0), | |
2314 | length, visited, type); | |
2315 | } | |
f255541f | 2316 | |
10a0d495 JJ |
2317 | if (type == 2) |
2318 | { | |
2319 | val = arg; | |
2320 | if (TREE_CODE (val) != INTEGER_CST | |
2321 | || tree_int_cst_sgn (val) < 0) | |
2322 | return false; | |
2323 | } | |
2324 | else | |
2325 | val = c_strlen (arg, 1); | |
750628d8 | 2326 | if (!val) |
06a9b53f | 2327 | return false; |
cd709752 | 2328 | |
10a0d495 JJ |
2329 | if (*length) |
2330 | { | |
2331 | if (type > 0) | |
2332 | { | |
2333 | if (TREE_CODE (*length) != INTEGER_CST | |
2334 | || TREE_CODE (val) != INTEGER_CST) | |
2335 | return false; | |
2336 | ||
2337 | if (tree_int_cst_lt (*length, val)) | |
2338 | *length = val; | |
2339 | return true; | |
2340 | } | |
2341 | else if (simple_cst_equal (val, *length) != 1) | |
2342 | return false; | |
2343 | } | |
6de9cd9a | 2344 | |
750628d8 DN |
2345 | *length = val; |
2346 | return true; | |
6de9cd9a | 2347 | } |
06a9b53f | 2348 | |
750628d8 DN |
2349 | /* If we were already here, break the infinite cycle. */ |
2350 | if (bitmap_bit_p (visited, SSA_NAME_VERSION (arg))) | |
2351 | return true; | |
2352 | bitmap_set_bit (visited, SSA_NAME_VERSION (arg)); | |
2353 | ||
2354 | var = arg; | |
2355 | def_stmt = SSA_NAME_DEF_STMT (var); | |
6de9cd9a | 2356 | |
750628d8 DN |
2357 | switch (TREE_CODE (def_stmt)) |
2358 | { | |
07beea0d | 2359 | case GIMPLE_MODIFY_STMT: |
750628d8 | 2360 | { |
10a0d495 JJ |
2361 | tree rhs; |
2362 | ||
750628d8 DN |
2363 | /* The RHS of the statement defining VAR must either have a |
2364 | constant length or come from another SSA_NAME with a constant | |
2365 | length. */ | |
07beea0d | 2366 | rhs = GIMPLE_STMT_OPERAND (def_stmt, 1); |
750628d8 | 2367 | STRIP_NOPS (rhs); |
10a0d495 | 2368 | return get_maxval_strlen (rhs, length, visited, type); |
750628d8 | 2369 | } |
6de9cd9a | 2370 | |
750628d8 DN |
2371 | case PHI_NODE: |
2372 | { | |
2373 | /* All the arguments of the PHI node must have the same constant | |
2374 | length. */ | |
2375 | int i; | |
6de9cd9a | 2376 | |
750628d8 DN |
2377 | for (i = 0; i < PHI_NUM_ARGS (def_stmt); i++) |
2378 | { | |
2379 | tree arg = PHI_ARG_DEF (def_stmt, i); | |
6de9cd9a | 2380 | |
750628d8 DN |
2381 | /* If this PHI has itself as an argument, we cannot |
2382 | determine the string length of this argument. However, | |
2383 | if we can find a constant string length for the other | |
2384 | PHI args then we can still be sure that this is a | |
2385 | constant string length. So be optimistic and just | |
2386 | continue with the next argument. */ | |
2387 | if (arg == PHI_RESULT (def_stmt)) | |
2388 | continue; | |
6de9cd9a | 2389 | |
10a0d495 | 2390 | if (!get_maxval_strlen (arg, length, visited, type)) |
750628d8 DN |
2391 | return false; |
2392 | } | |
6de9cd9a | 2393 | |
750628d8 | 2394 | return true; |
173b818d | 2395 | } |
6de9cd9a | 2396 | |
750628d8 DN |
2397 | default: |
2398 | break; | |
6de9cd9a DN |
2399 | } |
2400 | ||
750628d8 DN |
2401 | |
2402 | return false; | |
6de9cd9a DN |
2403 | } |
2404 | ||
2405 | ||
2406 | /* Fold builtin call FN in statement STMT. If it cannot be folded into a | |
2407 | constant, return NULL_TREE. Otherwise, return its constant value. */ | |
2408 | ||
2409 | static tree | |
2410 | ccp_fold_builtin (tree stmt, tree fn) | |
2411 | { | |
10a0d495 | 2412 | tree result, val[3]; |
5039610b | 2413 | tree callee, a; |
10a0d495 | 2414 | int arg_mask, i, type; |
a32e70c3 RS |
2415 | bitmap visited; |
2416 | bool ignore; | |
5039610b SL |
2417 | call_expr_arg_iterator iter; |
2418 | int nargs; | |
6de9cd9a | 2419 | |
07beea0d | 2420 | ignore = TREE_CODE (stmt) != GIMPLE_MODIFY_STMT; |
6de9cd9a DN |
2421 | |
2422 | /* First try the generic builtin folder. If that succeeds, return the | |
2423 | result directly. */ | |
5039610b | 2424 | result = fold_call_expr (fn, ignore); |
6de9cd9a | 2425 | if (result) |
10a0d495 JJ |
2426 | { |
2427 | if (ignore) | |
2428 | STRIP_NOPS (result); | |
2429 | return result; | |
2430 | } | |
a32e70c3 RS |
2431 | |
2432 | /* Ignore MD builtins. */ | |
5039610b | 2433 | callee = get_callee_fndecl (fn); |
a32e70c3 RS |
2434 | if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_MD) |
2435 | return NULL_TREE; | |
6de9cd9a DN |
2436 | |
2437 | /* If the builtin could not be folded, and it has no argument list, | |
2438 | we're done. */ | |
5039610b SL |
2439 | nargs = call_expr_nargs (fn); |
2440 | if (nargs == 0) | |
6de9cd9a DN |
2441 | return NULL_TREE; |
2442 | ||
2443 | /* Limit the work only for builtins we know how to simplify. */ | |
2444 | switch (DECL_FUNCTION_CODE (callee)) | |
2445 | { | |
2446 | case BUILT_IN_STRLEN: | |
2447 | case BUILT_IN_FPUTS: | |
2448 | case BUILT_IN_FPUTS_UNLOCKED: | |
10a0d495 JJ |
2449 | arg_mask = 1; |
2450 | type = 0; | |
6de9cd9a DN |
2451 | break; |
2452 | case BUILT_IN_STRCPY: | |
2453 | case BUILT_IN_STRNCPY: | |
10a0d495 JJ |
2454 | arg_mask = 2; |
2455 | type = 0; | |
2456 | break; | |
2457 | case BUILT_IN_MEMCPY_CHK: | |
2458 | case BUILT_IN_MEMPCPY_CHK: | |
2459 | case BUILT_IN_MEMMOVE_CHK: | |
2460 | case BUILT_IN_MEMSET_CHK: | |
2461 | case BUILT_IN_STRNCPY_CHK: | |
2462 | arg_mask = 4; | |
2463 | type = 2; | |
2464 | break; | |
2465 | case BUILT_IN_STRCPY_CHK: | |
2466 | case BUILT_IN_STPCPY_CHK: | |
2467 | arg_mask = 2; | |
2468 | type = 1; | |
2469 | break; | |
2470 | case BUILT_IN_SNPRINTF_CHK: | |
2471 | case BUILT_IN_VSNPRINTF_CHK: | |
2472 | arg_mask = 2; | |
2473 | type = 2; | |
6de9cd9a DN |
2474 | break; |
2475 | default: | |
2476 | return NULL_TREE; | |
2477 | } | |
2478 | ||
2479 | /* Try to use the dataflow information gathered by the CCP process. */ | |
8bdbfff5 | 2480 | visited = BITMAP_ALLOC (NULL); |
6de9cd9a | 2481 | |
10a0d495 | 2482 | memset (val, 0, sizeof (val)); |
5039610b SL |
2483 | init_call_expr_arg_iterator (fn, &iter); |
2484 | for (i = 0; arg_mask; i++, arg_mask >>= 1) | |
2485 | { | |
2486 | a = next_call_expr_arg (&iter); | |
2487 | if (arg_mask & 1) | |
2488 | { | |
2489 | bitmap_clear (visited); | |
2490 | if (!get_maxval_strlen (a, &val[i], visited, type)) | |
2491 | val[i] = NULL_TREE; | |
2492 | } | |
2493 | } | |
6de9cd9a | 2494 | |
8bdbfff5 | 2495 | BITMAP_FREE (visited); |
6de9cd9a | 2496 | |
a32e70c3 | 2497 | result = NULL_TREE; |
6de9cd9a DN |
2498 | switch (DECL_FUNCTION_CODE (callee)) |
2499 | { | |
2500 | case BUILT_IN_STRLEN: | |
10a0d495 | 2501 | if (val[0]) |
6de9cd9a | 2502 | { |
c22940cd | 2503 | tree new_val = fold_convert (TREE_TYPE (fn), val[0]); |
6de9cd9a DN |
2504 | |
2505 | /* If the result is not a valid gimple value, or not a cast | |
2506 | of a valid gimple value, then we can not use the result. */ | |
c22940cd TN |
2507 | if (is_gimple_val (new_val) |
2508 | || (is_gimple_cast (new_val) | |
2509 | && is_gimple_val (TREE_OPERAND (new_val, 0)))) | |
2510 | return new_val; | |
6de9cd9a | 2511 | } |
a32e70c3 RS |
2512 | break; |
2513 | ||
6de9cd9a | 2514 | case BUILT_IN_STRCPY: |
5039610b SL |
2515 | if (val[1] && is_gimple_val (val[1]) && nargs == 2) |
2516 | result = fold_builtin_strcpy (callee, | |
2517 | CALL_EXPR_ARG (fn, 0), | |
2518 | CALL_EXPR_ARG (fn, 1), | |
2519 | val[1]); | |
a32e70c3 RS |
2520 | break; |
2521 | ||
6de9cd9a | 2522 | case BUILT_IN_STRNCPY: |
5039610b SL |
2523 | if (val[1] && is_gimple_val (val[1]) && nargs == 3) |
2524 | result = fold_builtin_strncpy (callee, | |
2525 | CALL_EXPR_ARG (fn, 0), | |
2526 | CALL_EXPR_ARG (fn, 1), | |
2527 | CALL_EXPR_ARG (fn, 2), | |
2528 | val[1]); | |
a32e70c3 RS |
2529 | break; |
2530 | ||
6de9cd9a | 2531 | case BUILT_IN_FPUTS: |
5039610b SL |
2532 | result = fold_builtin_fputs (CALL_EXPR_ARG (fn, 0), |
2533 | CALL_EXPR_ARG (fn, 1), | |
07beea0d | 2534 | TREE_CODE (stmt) != GIMPLE_MODIFY_STMT, 0, |
10a0d495 | 2535 | val[0]); |
a32e70c3 RS |
2536 | break; |
2537 | ||
6de9cd9a | 2538 | case BUILT_IN_FPUTS_UNLOCKED: |
5039610b SL |
2539 | result = fold_builtin_fputs (CALL_EXPR_ARG (fn, 0), |
2540 | CALL_EXPR_ARG (fn, 1), | |
07beea0d | 2541 | TREE_CODE (stmt) != GIMPLE_MODIFY_STMT, 1, |
10a0d495 JJ |
2542 | val[0]); |
2543 | break; | |
2544 | ||
2545 | case BUILT_IN_MEMCPY_CHK: | |
2546 | case BUILT_IN_MEMPCPY_CHK: | |
2547 | case BUILT_IN_MEMMOVE_CHK: | |
2548 | case BUILT_IN_MEMSET_CHK: | |
2549 | if (val[2] && is_gimple_val (val[2])) | |
5039610b SL |
2550 | result = fold_builtin_memory_chk (callee, |
2551 | CALL_EXPR_ARG (fn, 0), | |
2552 | CALL_EXPR_ARG (fn, 1), | |
2553 | CALL_EXPR_ARG (fn, 2), | |
2554 | CALL_EXPR_ARG (fn, 3), | |
2555 | val[2], ignore, | |
10a0d495 JJ |
2556 | DECL_FUNCTION_CODE (callee)); |
2557 | break; | |
2558 | ||
2559 | case BUILT_IN_STRCPY_CHK: | |
2560 | case BUILT_IN_STPCPY_CHK: | |
2561 | if (val[1] && is_gimple_val (val[1])) | |
5039610b SL |
2562 | result = fold_builtin_stxcpy_chk (callee, |
2563 | CALL_EXPR_ARG (fn, 0), | |
2564 | CALL_EXPR_ARG (fn, 1), | |
2565 | CALL_EXPR_ARG (fn, 2), | |
2566 | val[1], ignore, | |
10a0d495 JJ |
2567 | DECL_FUNCTION_CODE (callee)); |
2568 | break; | |
2569 | ||
2570 | case BUILT_IN_STRNCPY_CHK: | |
2571 | if (val[2] && is_gimple_val (val[2])) | |
5039610b SL |
2572 | result = fold_builtin_strncpy_chk (CALL_EXPR_ARG (fn, 0), |
2573 | CALL_EXPR_ARG (fn, 1), | |
2574 | CALL_EXPR_ARG (fn, 2), | |
2575 | CALL_EXPR_ARG (fn, 3), | |
2576 | val[2]); | |
10a0d495 JJ |
2577 | break; |
2578 | ||
2579 | case BUILT_IN_SNPRINTF_CHK: | |
2580 | case BUILT_IN_VSNPRINTF_CHK: | |
2581 | if (val[1] && is_gimple_val (val[1])) | |
5039610b | 2582 | result = fold_builtin_snprintf_chk (fn, val[1], |
10a0d495 | 2583 | DECL_FUNCTION_CODE (callee)); |
a32e70c3 | 2584 | break; |
6de9cd9a DN |
2585 | |
2586 | default: | |
1e128c5f | 2587 | gcc_unreachable (); |
6de9cd9a DN |
2588 | } |
2589 | ||
a32e70c3 | 2590 | if (result && ignore) |
9675412f | 2591 | result = fold_ignored_result (result); |
a32e70c3 | 2592 | return result; |
6de9cd9a DN |
2593 | } |
2594 | ||
2595 | ||
206048bd | 2596 | /* Fold the statement pointed to by STMT_P. In some cases, this function may |
750628d8 DN |
2597 | replace the whole statement with a new one. Returns true iff folding |
2598 | makes any changes. */ | |
6de9cd9a | 2599 | |
750628d8 DN |
2600 | bool |
2601 | fold_stmt (tree *stmt_p) | |
6de9cd9a | 2602 | { |
750628d8 | 2603 | tree rhs, result, stmt; |
622f91ba | 2604 | struct fold_stmt_r_data fold_stmt_r_data; |
750628d8 | 2605 | bool changed = false; |
622f91ba JL |
2606 | bool inside_addr_expr = false; |
2607 | ||
6ac01510 ILT |
2608 | stmt = *stmt_p; |
2609 | ||
2610 | fold_stmt_r_data.stmt = stmt; | |
622f91ba JL |
2611 | fold_stmt_r_data.changed_p = &changed; |
2612 | fold_stmt_r_data.inside_addr_expr_p = &inside_addr_expr; | |
6de9cd9a | 2613 | |
750628d8 DN |
2614 | /* If we replaced constants and the statement makes pointer dereferences, |
2615 | then we may need to fold instances of *&VAR into VAR, etc. */ | |
622f91ba | 2616 | if (walk_tree (stmt_p, fold_stmt_r, &fold_stmt_r_data, NULL)) |
750628d8 | 2617 | { |
5039610b | 2618 | *stmt_p = build_call_expr (implicit_built_in_decls[BUILT_IN_TRAP], 0); |
6de9cd9a DN |
2619 | return true; |
2620 | } | |
2621 | ||
750628d8 DN |
2622 | rhs = get_rhs (stmt); |
2623 | if (!rhs) | |
2624 | return changed; | |
2625 | result = NULL_TREE; | |
6de9cd9a | 2626 | |
750628d8 | 2627 | if (TREE_CODE (rhs) == CALL_EXPR) |
6de9cd9a | 2628 | { |
750628d8 | 2629 | tree callee; |
6de9cd9a | 2630 | |
750628d8 DN |
2631 | /* Check for builtins that CCP can handle using information not |
2632 | available in the generic fold routines. */ | |
2633 | callee = get_callee_fndecl (rhs); | |
2634 | if (callee && DECL_BUILT_IN (callee)) | |
2635 | result = ccp_fold_builtin (stmt, rhs); | |
1809ff6b AP |
2636 | else |
2637 | { | |
2638 | /* Check for resolvable OBJ_TYPE_REF. The only sorts we can resolve | |
2639 | here are when we've propagated the address of a decl into the | |
2640 | object slot. */ | |
2641 | /* ??? Should perhaps do this in fold proper. However, doing it | |
2642 | there requires that we create a new CALL_EXPR, and that requires | |
2643 | copying EH region info to the new node. Easier to just do it | |
2644 | here where we can just smash the call operand. Also | |
2645 | CALL_EXPR_RETURN_SLOT_OPT needs to be handled correctly and | |
5039610b SL |
2646 | copied, fold_call_expr does not have not information. */ |
2647 | callee = CALL_EXPR_FN (rhs); | |
1809ff6b AP |
2648 | if (TREE_CODE (callee) == OBJ_TYPE_REF |
2649 | && lang_hooks.fold_obj_type_ref | |
2650 | && TREE_CODE (OBJ_TYPE_REF_OBJECT (callee)) == ADDR_EXPR | |
2651 | && DECL_P (TREE_OPERAND | |
2652 | (OBJ_TYPE_REF_OBJECT (callee), 0))) | |
2653 | { | |
2654 | tree t; | |
2655 | ||
2656 | /* ??? Caution: Broken ADDR_EXPR semantics means that | |
2657 | looking at the type of the operand of the addr_expr | |
2658 | can yield an array type. See silly exception in | |
2659 | check_pointer_types_r. */ | |
2660 | ||
2661 | t = TREE_TYPE (TREE_TYPE (OBJ_TYPE_REF_OBJECT (callee))); | |
2662 | t = lang_hooks.fold_obj_type_ref (callee, t); | |
2663 | if (t) | |
2664 | { | |
5039610b | 2665 | CALL_EXPR_FN (rhs) = t; |
1809ff6b AP |
2666 | changed = true; |
2667 | } | |
2668 | } | |
2669 | } | |
6de9cd9a | 2670 | } |
f255541f RC |
2671 | else if (TREE_CODE (rhs) == COND_EXPR) |
2672 | { | |
2673 | tree temp = fold (COND_EXPR_COND (rhs)); | |
2674 | if (temp != COND_EXPR_COND (rhs)) | |
2675 | result = fold_build3 (COND_EXPR, TREE_TYPE (rhs), temp, | |
2676 | COND_EXPR_THEN (rhs), COND_EXPR_ELSE (rhs)); | |
2677 | } | |
6de9cd9a | 2678 | |
750628d8 DN |
2679 | /* If we couldn't fold the RHS, hand over to the generic fold routines. */ |
2680 | if (result == NULL_TREE) | |
2681 | result = fold (rhs); | |
6de9cd9a | 2682 | |
750628d8 DN |
2683 | /* Strip away useless type conversions. Both the NON_LVALUE_EXPR that |
2684 | may have been added by fold, and "useless" type conversions that might | |
2685 | now be apparent due to propagation. */ | |
2686 | STRIP_USELESS_TYPE_CONVERSION (result); | |
2687 | ||
2688 | if (result != rhs) | |
2689 | changed |= set_rhs (stmt_p, result); | |
2690 | ||
2691 | return changed; | |
6de9cd9a DN |
2692 | } |
2693 | ||
38965eb2 ZD |
2694 | /* Perform the minimal folding on statement STMT. Only operations like |
2695 | *&x created by constant propagation are handled. The statement cannot | |
2696 | be replaced with a new one. */ | |
2697 | ||
2698 | bool | |
2699 | fold_stmt_inplace (tree stmt) | |
2700 | { | |
2701 | tree old_stmt = stmt, rhs, new_rhs; | |
622f91ba | 2702 | struct fold_stmt_r_data fold_stmt_r_data; |
38965eb2 | 2703 | bool changed = false; |
622f91ba JL |
2704 | bool inside_addr_expr = false; |
2705 | ||
6ac01510 | 2706 | fold_stmt_r_data.stmt = stmt; |
622f91ba JL |
2707 | fold_stmt_r_data.changed_p = &changed; |
2708 | fold_stmt_r_data.inside_addr_expr_p = &inside_addr_expr; | |
38965eb2 | 2709 | |
622f91ba | 2710 | walk_tree (&stmt, fold_stmt_r, &fold_stmt_r_data, NULL); |
38965eb2 ZD |
2711 | gcc_assert (stmt == old_stmt); |
2712 | ||
2713 | rhs = get_rhs (stmt); | |
2714 | if (!rhs || rhs == stmt) | |
2715 | return changed; | |
2716 | ||
2717 | new_rhs = fold (rhs); | |
43e364dd | 2718 | STRIP_USELESS_TYPE_CONVERSION (new_rhs); |
38965eb2 ZD |
2719 | if (new_rhs == rhs) |
2720 | return changed; | |
2721 | ||
2722 | changed |= set_rhs (&stmt, new_rhs); | |
2723 | gcc_assert (stmt == old_stmt); | |
2724 | ||
2725 | return changed; | |
2726 | } | |
6de9cd9a | 2727 | \f |
cb8e078d JJ |
2728 | /* Try to optimize out __builtin_stack_restore. Optimize it out |
2729 | if there is another __builtin_stack_restore in the same basic | |
2730 | block and no calls or ASM_EXPRs are in between, or if this block's | |
2731 | only outgoing edge is to EXIT_BLOCK and there are no calls or | |
2732 | ASM_EXPRs after this __builtin_stack_restore. */ | |
2733 | ||
2734 | static tree | |
2735 | optimize_stack_restore (basic_block bb, tree call, block_stmt_iterator i) | |
2736 | { | |
2737 | tree stack_save, stmt, callee; | |
2738 | ||
2739 | if (TREE_CODE (call) != CALL_EXPR | |
2740 | || call_expr_nargs (call) != 1 | |
2741 | || TREE_CODE (CALL_EXPR_ARG (call, 0)) != SSA_NAME | |
2742 | || !POINTER_TYPE_P (TREE_TYPE (CALL_EXPR_ARG (call, 0)))) | |
2743 | return NULL_TREE; | |
2744 | ||
2745 | for (bsi_next (&i); !bsi_end_p (i); bsi_next (&i)) | |
2746 | { | |
2747 | tree call; | |
2748 | ||
2749 | stmt = bsi_stmt (i); | |
2750 | if (TREE_CODE (stmt) == ASM_EXPR) | |
2751 | return NULL_TREE; | |
2752 | call = get_call_expr_in (stmt); | |
2753 | if (call == NULL) | |
2754 | continue; | |
2755 | ||
2756 | callee = get_callee_fndecl (call); | |
2757 | if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) | |
2758 | return NULL_TREE; | |
2759 | ||
2760 | if (DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_RESTORE) | |
2761 | break; | |
2762 | } | |
2763 | ||
2764 | if (bsi_end_p (i) | |
2765 | && (! single_succ_p (bb) | |
2766 | || single_succ_edge (bb)->dest != EXIT_BLOCK_PTR)) | |
2767 | return NULL_TREE; | |
2768 | ||
2769 | stack_save = SSA_NAME_DEF_STMT (CALL_EXPR_ARG (call, 0)); | |
2770 | if (TREE_CODE (stack_save) != GIMPLE_MODIFY_STMT | |
2771 | || GIMPLE_STMT_OPERAND (stack_save, 0) != CALL_EXPR_ARG (call, 0) | |
2772 | || TREE_CODE (GIMPLE_STMT_OPERAND (stack_save, 1)) != CALL_EXPR | |
2773 | || tree_could_throw_p (stack_save) | |
2774 | || !has_single_use (CALL_EXPR_ARG (call, 0))) | |
2775 | return NULL_TREE; | |
2776 | ||
2777 | callee = get_callee_fndecl (GIMPLE_STMT_OPERAND (stack_save, 1)); | |
2778 | if (!callee | |
2779 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL | |
2780 | || DECL_FUNCTION_CODE (callee) != BUILT_IN_STACK_SAVE | |
2781 | || call_expr_nargs (GIMPLE_STMT_OPERAND (stack_save, 1)) != 0) | |
2782 | return NULL_TREE; | |
2783 | ||
2784 | stmt = stack_save; | |
2785 | push_stmt_changes (&stmt); | |
2786 | if (!set_rhs (&stmt, | |
2787 | build_int_cst (TREE_TYPE (CALL_EXPR_ARG (call, 0)), 0))) | |
2788 | { | |
2789 | discard_stmt_changes (&stmt); | |
2790 | return NULL_TREE; | |
2791 | } | |
2792 | gcc_assert (stmt == stack_save); | |
2793 | pop_stmt_changes (&stmt); | |
2794 | ||
2795 | return integer_zero_node; | |
2796 | } | |
2797 | \f | |
d7bd8aeb JJ |
2798 | /* If va_list type is a simple pointer and nothing special is needed, |
2799 | optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0), | |
2800 | __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple | |
2801 | pointer assignment. */ | |
2802 | ||
2803 | static tree | |
2804 | optimize_stdarg_builtin (tree call) | |
2805 | { | |
2806 | tree callee, lhs, rhs; | |
2807 | bool va_list_simple_ptr; | |
2808 | ||
2809 | if (TREE_CODE (call) != CALL_EXPR) | |
2810 | return NULL_TREE; | |
2811 | ||
2812 | va_list_simple_ptr = POINTER_TYPE_P (va_list_type_node) | |
2813 | && (TREE_TYPE (va_list_type_node) == void_type_node | |
2814 | || TREE_TYPE (va_list_type_node) == char_type_node); | |
2815 | ||
2816 | callee = get_callee_fndecl (call); | |
2817 | switch (DECL_FUNCTION_CODE (callee)) | |
2818 | { | |
2819 | case BUILT_IN_VA_START: | |
2820 | if (!va_list_simple_ptr | |
2821 | || targetm.expand_builtin_va_start != NULL | |
2822 | || built_in_decls[BUILT_IN_NEXT_ARG] == NULL) | |
2823 | return NULL_TREE; | |
2824 | ||
2825 | if (call_expr_nargs (call) != 2) | |
2826 | return NULL_TREE; | |
2827 | ||
2828 | lhs = CALL_EXPR_ARG (call, 0); | |
2829 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) | |
2830 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
2831 | != TYPE_MAIN_VARIANT (va_list_type_node)) | |
2832 | return NULL_TREE; | |
2833 | ||
2834 | lhs = build_fold_indirect_ref (lhs); | |
2835 | rhs = build_call_expr (built_in_decls[BUILT_IN_NEXT_ARG], | |
2836 | 1, integer_zero_node); | |
2837 | rhs = fold_convert (TREE_TYPE (lhs), rhs); | |
2838 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); | |
2839 | ||
2840 | case BUILT_IN_VA_COPY: | |
2841 | if (!va_list_simple_ptr) | |
2842 | return NULL_TREE; | |
2843 | ||
2844 | if (call_expr_nargs (call) != 2) | |
2845 | return NULL_TREE; | |
2846 | ||
2847 | lhs = CALL_EXPR_ARG (call, 0); | |
2848 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) | |
2849 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
2850 | != TYPE_MAIN_VARIANT (va_list_type_node)) | |
2851 | return NULL_TREE; | |
2852 | ||
2853 | lhs = build_fold_indirect_ref (lhs); | |
2854 | rhs = CALL_EXPR_ARG (call, 1); | |
2855 | if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs)) | |
2856 | != TYPE_MAIN_VARIANT (va_list_type_node)) | |
2857 | return NULL_TREE; | |
2858 | ||
2859 | rhs = fold_convert (TREE_TYPE (lhs), rhs); | |
2860 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); | |
2861 | ||
2862 | case BUILT_IN_VA_END: | |
2863 | return integer_zero_node; | |
2864 | ||
2865 | default: | |
2866 | gcc_unreachable (); | |
2867 | } | |
2868 | } | |
2869 | \f | |
b28b1600 JJ |
2870 | /* Convert EXPR into a GIMPLE value suitable for substitution on the |
2871 | RHS of an assignment. Insert the necessary statements before | |
2e929cf3 JH |
2872 | iterator *SI_P. |
2873 | When IGNORE is set, don't worry about the return value. */ | |
b28b1600 JJ |
2874 | |
2875 | static tree | |
2e929cf3 | 2876 | convert_to_gimple_builtin (block_stmt_iterator *si_p, tree expr, bool ignore) |
b28b1600 JJ |
2877 | { |
2878 | tree_stmt_iterator ti; | |
2879 | tree stmt = bsi_stmt (*si_p); | |
2880 | tree tmp, stmts = NULL; | |
2881 | ||
2882 | push_gimplify_context (); | |
2e929cf3 JH |
2883 | if (ignore) |
2884 | { | |
2885 | tmp = build_empty_stmt (); | |
2886 | gimplify_and_add (expr, &stmts); | |
2887 | } | |
2888 | else | |
2889 | tmp = get_initialized_tmp_var (expr, &stmts, NULL); | |
b28b1600 JJ |
2890 | pop_gimplify_context (NULL); |
2891 | ||
f47c96aa AM |
2892 | if (EXPR_HAS_LOCATION (stmt)) |
2893 | annotate_all_with_locus (&stmts, EXPR_LOCATION (stmt)); | |
2894 | ||
b28b1600 JJ |
2895 | /* The replacement can expose previously unreferenced variables. */ |
2896 | for (ti = tsi_start (stmts); !tsi_end_p (ti); tsi_next (&ti)) | |
2897 | { | |
f47c96aa | 2898 | tree new_stmt = tsi_stmt (ti); |
b28b1600 | 2899 | find_new_referenced_vars (tsi_stmt_ptr (ti)); |
f47c96aa | 2900 | bsi_insert_before (si_p, new_stmt, BSI_NEW_STMT); |
cfaab3a9 | 2901 | mark_symbols_for_renaming (new_stmt); |
f47c96aa | 2902 | bsi_next (si_p); |
b28b1600 JJ |
2903 | } |
2904 | ||
b28b1600 JJ |
2905 | return tmp; |
2906 | } | |
2907 | ||
2908 | ||
6de9cd9a DN |
2909 | /* A simple pass that attempts to fold all builtin functions. This pass |
2910 | is run after we've propagated as many constants as we can. */ | |
2911 | ||
c2924966 | 2912 | static unsigned int |
6de9cd9a DN |
2913 | execute_fold_all_builtins (void) |
2914 | { | |
a7d6ba24 | 2915 | bool cfg_changed = false; |
6de9cd9a | 2916 | basic_block bb; |
7b0e48fb DB |
2917 | unsigned int todoflags = 0; |
2918 | ||
6de9cd9a DN |
2919 | FOR_EACH_BB (bb) |
2920 | { | |
2921 | block_stmt_iterator i; | |
10a0d495 | 2922 | for (i = bsi_start (bb); !bsi_end_p (i); ) |
6de9cd9a DN |
2923 | { |
2924 | tree *stmtp = bsi_stmt_ptr (i); | |
af47810a | 2925 | tree old_stmt = *stmtp; |
6de9cd9a DN |
2926 | tree call = get_rhs (*stmtp); |
2927 | tree callee, result; | |
10a0d495 | 2928 | enum built_in_function fcode; |
6de9cd9a DN |
2929 | |
2930 | if (!call || TREE_CODE (call) != CALL_EXPR) | |
10a0d495 JJ |
2931 | { |
2932 | bsi_next (&i); | |
2933 | continue; | |
2934 | } | |
6de9cd9a DN |
2935 | callee = get_callee_fndecl (call); |
2936 | if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) | |
10a0d495 JJ |
2937 | { |
2938 | bsi_next (&i); | |
2939 | continue; | |
2940 | } | |
2941 | fcode = DECL_FUNCTION_CODE (callee); | |
6de9cd9a DN |
2942 | |
2943 | result = ccp_fold_builtin (*stmtp, call); | |
2944 | if (!result) | |
2945 | switch (DECL_FUNCTION_CODE (callee)) | |
2946 | { | |
2947 | case BUILT_IN_CONSTANT_P: | |
2948 | /* Resolve __builtin_constant_p. If it hasn't been | |
2949 | folded to integer_one_node by now, it's fairly | |
2950 | certain that the value simply isn't constant. */ | |
2951 | result = integer_zero_node; | |
2952 | break; | |
2953 | ||
cb8e078d JJ |
2954 | case BUILT_IN_STACK_RESTORE: |
2955 | result = optimize_stack_restore (bb, *stmtp, i); | |
d7bd8aeb JJ |
2956 | if (result) |
2957 | break; | |
2958 | bsi_next (&i); | |
2959 | continue; | |
2960 | ||
2961 | case BUILT_IN_VA_START: | |
2962 | case BUILT_IN_VA_END: | |
2963 | case BUILT_IN_VA_COPY: | |
2964 | /* These shouldn't be folded before pass_stdarg. */ | |
2965 | result = optimize_stdarg_builtin (*stmtp); | |
cb8e078d JJ |
2966 | if (result) |
2967 | break; | |
2968 | /* FALLTHRU */ | |
2969 | ||
6de9cd9a | 2970 | default: |
10a0d495 | 2971 | bsi_next (&i); |
6de9cd9a DN |
2972 | continue; |
2973 | } | |
2974 | ||
2975 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2976 | { | |
2977 | fprintf (dump_file, "Simplified\n "); | |
2978 | print_generic_stmt (dump_file, *stmtp, dump_flags); | |
2979 | } | |
2980 | ||
cfaab3a9 DN |
2981 | push_stmt_changes (stmtp); |
2982 | ||
b28b1600 JJ |
2983 | if (!set_rhs (stmtp, result)) |
2984 | { | |
2e929cf3 JH |
2985 | result = convert_to_gimple_builtin (&i, result, |
2986 | TREE_CODE (old_stmt) | |
07beea0d | 2987 | != GIMPLE_MODIFY_STMT); |
e16acfcd NS |
2988 | if (result) |
2989 | { | |
2990 | bool ok = set_rhs (stmtp, result); | |
e16acfcd | 2991 | gcc_assert (ok); |
7b0e48fb | 2992 | todoflags |= TODO_rebuild_alias; |
e16acfcd | 2993 | } |
b28b1600 | 2994 | } |
cfaab3a9 DN |
2995 | |
2996 | pop_stmt_changes (stmtp); | |
2997 | ||
af47810a | 2998 | if (maybe_clean_or_replace_eh_stmt (old_stmt, *stmtp) |
a7d6ba24 JJ |
2999 | && tree_purge_dead_eh_edges (bb)) |
3000 | cfg_changed = true; | |
6de9cd9a DN |
3001 | |
3002 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3003 | { | |
3004 | fprintf (dump_file, "to\n "); | |
3005 | print_generic_stmt (dump_file, *stmtp, dump_flags); | |
3006 | fprintf (dump_file, "\n"); | |
3007 | } | |
10a0d495 JJ |
3008 | |
3009 | /* Retry the same statement if it changed into another | |
3010 | builtin, there might be new opportunities now. */ | |
3011 | call = get_rhs (*stmtp); | |
3012 | if (!call || TREE_CODE (call) != CALL_EXPR) | |
3013 | { | |
3014 | bsi_next (&i); | |
3015 | continue; | |
3016 | } | |
3017 | callee = get_callee_fndecl (call); | |
3018 | if (!callee | |
3019 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL | |
3020 | || DECL_FUNCTION_CODE (callee) == fcode) | |
3021 | bsi_next (&i); | |
6de9cd9a DN |
3022 | } |
3023 | } | |
7b0e48fb | 3024 | |
a7d6ba24 | 3025 | /* Delete unreachable blocks. */ |
7b0e48fb DB |
3026 | if (cfg_changed) |
3027 | todoflags |= TODO_cleanup_cfg; | |
3028 | ||
3029 | return todoflags; | |
6de9cd9a DN |
3030 | } |
3031 | ||
750628d8 | 3032 | |
8ddbbcae | 3033 | struct gimple_opt_pass pass_fold_builtins = |
6de9cd9a | 3034 | { |
8ddbbcae JH |
3035 | { |
3036 | GIMPLE_PASS, | |
6de9cd9a DN |
3037 | "fab", /* name */ |
3038 | NULL, /* gate */ | |
3039 | execute_fold_all_builtins, /* execute */ | |
3040 | NULL, /* sub */ | |
3041 | NULL, /* next */ | |
3042 | 0, /* static_pass_number */ | |
3043 | 0, /* tv_id */ | |
7faade0f | 3044 | PROP_cfg | PROP_ssa, /* properties_required */ |
6de9cd9a DN |
3045 | 0, /* properties_provided */ |
3046 | 0, /* properties_destroyed */ | |
3047 | 0, /* todo_flags_start */ | |
b28b1600 JJ |
3048 | TODO_dump_func |
3049 | | TODO_verify_ssa | |
8ddbbcae JH |
3050 | | TODO_update_ssa /* todo_flags_finish */ |
3051 | } | |
6de9cd9a | 3052 | }; |