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6de9cd9a | 1 | /* Conditional constant propagation pass for the GNU compiler. |
fa10beec | 2 | Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 |
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 | 206 | #include "tree-ssa-propagate.h" |
53a8f709 | 207 | #include "value-prof.h" |
750628d8 | 208 | #include "langhooks.h" |
ae3df618 | 209 | #include "target.h" |
6ac01510 | 210 | #include "toplev.h" |
6de9cd9a DN |
211 | |
212 | ||
213 | /* Possible lattice values. */ | |
214 | typedef enum | |
215 | { | |
106dec71 | 216 | UNINITIALIZED, |
6de9cd9a DN |
217 | UNDEFINED, |
218 | CONSTANT, | |
219 | VARYING | |
0bca51f0 | 220 | } ccp_lattice_t; |
6de9cd9a | 221 | |
0bca51f0 DN |
222 | /* Array of propagated constant values. After propagation, |
223 | CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If | |
224 | the constant is held in an SSA name representing a memory store | |
38635499 DN |
225 | (i.e., a VDEF), CONST_VAL[I].MEM_REF will contain the actual |
226 | memory reference used to store (i.e., the LHS of the assignment | |
227 | doing the store). */ | |
404f4351 | 228 | static prop_value_t *const_val; |
6de9cd9a | 229 | |
0bca51f0 | 230 | /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */ |
95eec0d6 DB |
231 | |
232 | static void | |
0bca51f0 | 233 | dump_lattice_value (FILE *outf, const char *prefix, prop_value_t val) |
95eec0d6 | 234 | { |
750628d8 | 235 | switch (val.lattice_val) |
95eec0d6 | 236 | { |
0bca51f0 DN |
237 | case UNINITIALIZED: |
238 | fprintf (outf, "%sUNINITIALIZED", prefix); | |
239 | break; | |
750628d8 DN |
240 | case UNDEFINED: |
241 | fprintf (outf, "%sUNDEFINED", prefix); | |
242 | break; | |
243 | case VARYING: | |
244 | fprintf (outf, "%sVARYING", prefix); | |
245 | break; | |
750628d8 DN |
246 | case CONSTANT: |
247 | fprintf (outf, "%sCONSTANT ", prefix); | |
0bca51f0 | 248 | print_generic_expr (outf, val.value, dump_flags); |
750628d8 DN |
249 | break; |
250 | default: | |
1e128c5f | 251 | gcc_unreachable (); |
750628d8 | 252 | } |
95eec0d6 | 253 | } |
6de9cd9a | 254 | |
6de9cd9a | 255 | |
0bca51f0 DN |
256 | /* Print lattice value VAL to stderr. */ |
257 | ||
258 | void debug_lattice_value (prop_value_t val); | |
259 | ||
260 | void | |
261 | debug_lattice_value (prop_value_t val) | |
262 | { | |
263 | dump_lattice_value (stderr, "", val); | |
264 | fprintf (stderr, "\n"); | |
265 | } | |
6de9cd9a | 266 | |
6de9cd9a | 267 | |
726a989a | 268 | |
fc9962ee ZD |
269 | /* If SYM is a constant variable with known value, return the value. |
270 | NULL_TREE is returned otherwise. */ | |
271 | ||
ed97ddc6 | 272 | tree |
fc9962ee ZD |
273 | get_symbol_constant_value (tree sym) |
274 | { | |
275 | if (TREE_STATIC (sym) | |
276 | && TREE_READONLY (sym) | |
ed97ddc6 | 277 | && !MTAG_P (sym)) |
fc9962ee ZD |
278 | { |
279 | tree val = DECL_INITIAL (sym); | |
62bc00e2 RG |
280 | if (val) |
281 | { | |
282 | STRIP_USELESS_TYPE_CONVERSION (val); | |
283 | if (is_gimple_min_invariant (val)) | |
284 | return val; | |
285 | } | |
b0940154 | 286 | /* Variables declared 'const' without an initializer |
fa10beec | 287 | have zero as the initializer if they may not be |
ed97ddc6 | 288 | overridden at link or run time. */ |
b0940154 | 289 | if (!val |
ed97ddc6 | 290 | && targetm.binds_local_p (sym) |
b0940154 AP |
291 | && (INTEGRAL_TYPE_P (TREE_TYPE (sym)) |
292 | || SCALAR_FLOAT_TYPE_P (TREE_TYPE (sym)))) | |
293 | return fold_convert (TREE_TYPE (sym), integer_zero_node); | |
fc9962ee ZD |
294 | } |
295 | ||
296 | return NULL_TREE; | |
297 | } | |
688e936d | 298 | |
0bca51f0 DN |
299 | /* Compute a default value for variable VAR and store it in the |
300 | CONST_VAL array. The following rules are used to get default | |
301 | values: | |
95eec0d6 | 302 | |
0bca51f0 DN |
303 | 1- Global and static variables that are declared constant are |
304 | considered CONSTANT. | |
305 | ||
306 | 2- Any other value is considered UNDEFINED. This is useful when | |
750628d8 DN |
307 | considering PHI nodes. PHI arguments that are undefined do not |
308 | change the constant value of the PHI node, which allows for more | |
0bca51f0 | 309 | constants to be propagated. |
6de9cd9a | 310 | |
caf55296 | 311 | 3- Variables defined by statements other than assignments and PHI |
0bca51f0 | 312 | nodes are considered VARYING. |
6de9cd9a | 313 | |
caf55296 | 314 | 4- Initial values of variables that are not GIMPLE registers are |
106dec71 | 315 | considered VARYING. */ |
6de9cd9a | 316 | |
0bca51f0 DN |
317 | static prop_value_t |
318 | get_default_value (tree var) | |
319 | { | |
320 | tree sym = SSA_NAME_VAR (var); | |
dce2b2f6 | 321 | prop_value_t val = { UNINITIALIZED, NULL_TREE }; |
fc9962ee | 322 | tree cst_val; |
106dec71 | 323 | |
dce2b2f6 | 324 | if (!is_gimple_reg (var)) |
6de9cd9a | 325 | { |
0bca51f0 DN |
326 | /* Short circuit for regular CCP. We are not interested in any |
327 | non-register when DO_STORE_CCP is false. */ | |
750628d8 | 328 | val.lattice_val = VARYING; |
6de9cd9a | 329 | } |
fc9962ee | 330 | else if ((cst_val = get_symbol_constant_value (sym)) != NULL_TREE) |
750628d8 | 331 | { |
0bca51f0 DN |
332 | /* Globals and static variables declared 'const' take their |
333 | initial value. */ | |
334 | val.lattice_val = CONSTANT; | |
fc9962ee | 335 | val.value = cst_val; |
750628d8 DN |
336 | } |
337 | else | |
338 | { | |
726a989a | 339 | gimple stmt = SSA_NAME_DEF_STMT (var); |
6de9cd9a | 340 | |
726a989a | 341 | if (gimple_nop_p (stmt)) |
0bca51f0 DN |
342 | { |
343 | /* Variables defined by an empty statement are those used | |
344 | before being initialized. If VAR is a local variable, we | |
106dec71 ZD |
345 | can assume initially that it is UNDEFINED, otherwise we must |
346 | consider it VARYING. */ | |
0bca51f0 DN |
347 | if (is_gimple_reg (sym) && TREE_CODE (sym) != PARM_DECL) |
348 | val.lattice_val = UNDEFINED; | |
0bca51f0 | 349 | else |
750628d8 DN |
350 | val.lattice_val = VARYING; |
351 | } | |
726a989a RB |
352 | else if (is_gimple_assign (stmt) |
353 | /* Value-returning GIMPLE_CALL statements assign to | |
354 | a variable, and are treated similarly to GIMPLE_ASSIGN. */ | |
355 | || (is_gimple_call (stmt) | |
356 | && gimple_call_lhs (stmt) != NULL_TREE) | |
357 | || gimple_code (stmt) == GIMPLE_PHI) | |
358 | { | |
0bca51f0 | 359 | /* Any other variable defined by an assignment or a PHI node |
106dec71 ZD |
360 | is considered UNDEFINED. */ |
361 | val.lattice_val = UNDEFINED; | |
0bca51f0 DN |
362 | } |
363 | else | |
364 | { | |
365 | /* Otherwise, VAR will never take on a constant value. */ | |
366 | val.lattice_val = VARYING; | |
367 | } | |
750628d8 | 368 | } |
6de9cd9a | 369 | |
750628d8 DN |
370 | return val; |
371 | } | |
6de9cd9a | 372 | |
6de9cd9a | 373 | |
106dec71 | 374 | /* Get the constant value associated with variable VAR. */ |
6de9cd9a | 375 | |
106dec71 ZD |
376 | static inline prop_value_t * |
377 | get_value (tree var) | |
0bca51f0 | 378 | { |
ed97ddc6 | 379 | prop_value_t *val; |
106dec71 | 380 | |
ed97ddc6 RG |
381 | if (const_val == NULL) |
382 | return NULL; | |
383 | ||
384 | val = &const_val[SSA_NAME_VERSION (var)]; | |
106dec71 | 385 | if (val->lattice_val == UNINITIALIZED) |
6de9cd9a DN |
386 | *val = get_default_value (var); |
387 | ||
388 | return val; | |
389 | } | |
390 | ||
106dec71 ZD |
391 | /* Sets the value associated with VAR to VARYING. */ |
392 | ||
393 | static inline void | |
394 | set_value_varying (tree var) | |
395 | { | |
396 | prop_value_t *val = &const_val[SSA_NAME_VERSION (var)]; | |
397 | ||
398 | val->lattice_val = VARYING; | |
399 | val->value = NULL_TREE; | |
106dec71 | 400 | } |
6de9cd9a | 401 | |
fbb5445b L |
402 | /* For float types, modify the value of VAL to make ccp work correctly |
403 | for non-standard values (-0, NaN): | |
404 | ||
405 | If HONOR_SIGNED_ZEROS is false, and VAL = -0, we canonicalize it to 0. | |
406 | If HONOR_NANS is false, and VAL is NaN, we canonicalize it to UNDEFINED. | |
407 | This is to fix the following problem (see PR 29921): Suppose we have | |
408 | ||
409 | x = 0.0 * y | |
410 | ||
411 | and we set value of y to NaN. This causes value of x to be set to NaN. | |
412 | When we later determine that y is in fact VARYING, fold uses the fact | |
413 | that HONOR_NANS is false, and we try to change the value of x to 0, | |
414 | causing an ICE. With HONOR_NANS being false, the real appearance of | |
415 | NaN would cause undefined behavior, though, so claiming that y (and x) | |
416 | are UNDEFINED initially is correct. */ | |
417 | ||
418 | static void | |
419 | canonicalize_float_value (prop_value_t *val) | |
420 | { | |
421 | enum machine_mode mode; | |
422 | tree type; | |
423 | REAL_VALUE_TYPE d; | |
424 | ||
425 | if (val->lattice_val != CONSTANT | |
426 | || TREE_CODE (val->value) != REAL_CST) | |
427 | return; | |
428 | ||
429 | d = TREE_REAL_CST (val->value); | |
430 | type = TREE_TYPE (val->value); | |
431 | mode = TYPE_MODE (type); | |
432 | ||
433 | if (!HONOR_SIGNED_ZEROS (mode) | |
434 | && REAL_VALUE_MINUS_ZERO (d)) | |
435 | { | |
436 | val->value = build_real (type, dconst0); | |
437 | return; | |
438 | } | |
439 | ||
440 | if (!HONOR_NANS (mode) | |
441 | && REAL_VALUE_ISNAN (d)) | |
442 | { | |
443 | val->lattice_val = UNDEFINED; | |
444 | val->value = NULL; | |
fbb5445b L |
445 | return; |
446 | } | |
447 | } | |
448 | ||
0bca51f0 DN |
449 | /* Set the value for variable VAR to NEW_VAL. Return true if the new |
450 | value is different from VAR's previous value. */ | |
6de9cd9a | 451 | |
750628d8 | 452 | static bool |
0bca51f0 | 453 | set_lattice_value (tree var, prop_value_t new_val) |
6de9cd9a | 454 | { |
106dec71 | 455 | prop_value_t *old_val = get_value (var); |
0bca51f0 | 456 | |
fbb5445b L |
457 | canonicalize_float_value (&new_val); |
458 | ||
0bca51f0 | 459 | /* Lattice transitions must always be monotonically increasing in |
106dec71 ZD |
460 | value. If *OLD_VAL and NEW_VAL are the same, return false to |
461 | inform the caller that this was a non-transition. */ | |
462 | ||
fc9962ee | 463 | gcc_assert (old_val->lattice_val < new_val.lattice_val |
0bca51f0 | 464 | || (old_val->lattice_val == new_val.lattice_val |
fc9962ee | 465 | && ((!old_val->value && !new_val.value) |
dce2b2f6 | 466 | || operand_equal_p (old_val->value, new_val.value, 0)))); |
0bca51f0 DN |
467 | |
468 | if (old_val->lattice_val != new_val.lattice_val) | |
6de9cd9a | 469 | { |
750628d8 DN |
470 | if (dump_file && (dump_flags & TDF_DETAILS)) |
471 | { | |
0bca51f0 | 472 | dump_lattice_value (dump_file, "Lattice value changed to ", new_val); |
106dec71 | 473 | fprintf (dump_file, ". Adding SSA edges to worklist.\n"); |
750628d8 DN |
474 | } |
475 | ||
0bca51f0 DN |
476 | *old_val = new_val; |
477 | ||
106dec71 ZD |
478 | gcc_assert (new_val.lattice_val != UNDEFINED); |
479 | return true; | |
6de9cd9a | 480 | } |
750628d8 DN |
481 | |
482 | return false; | |
6de9cd9a DN |
483 | } |
484 | ||
485 | ||
0bca51f0 | 486 | /* Return the likely CCP lattice value for STMT. |
6de9cd9a | 487 | |
750628d8 | 488 | If STMT has no operands, then return CONSTANT. |
6de9cd9a | 489 | |
7f879c96 RG |
490 | Else if undefinedness of operands of STMT cause its value to be |
491 | undefined, then return UNDEFINED. | |
6de9cd9a | 492 | |
750628d8 | 493 | Else if any operands of STMT are constants, then return CONSTANT. |
6de9cd9a | 494 | |
750628d8 | 495 | Else return VARYING. */ |
6de9cd9a | 496 | |
0bca51f0 | 497 | static ccp_lattice_t |
726a989a | 498 | likely_value (gimple stmt) |
750628d8 | 499 | { |
7f879c96 | 500 | bool has_constant_operand, has_undefined_operand, all_undefined_operands; |
750628d8 DN |
501 | tree use; |
502 | ssa_op_iter iter; | |
6de9cd9a | 503 | |
e0c68ce9 | 504 | enum gimple_code code = gimple_code (stmt); |
726a989a RB |
505 | |
506 | /* This function appears to be called only for assignments, calls, | |
507 | conditionals, and switches, due to the logic in visit_stmt. */ | |
508 | gcc_assert (code == GIMPLE_ASSIGN | |
509 | || code == GIMPLE_CALL | |
510 | || code == GIMPLE_COND | |
511 | || code == GIMPLE_SWITCH); | |
0bca51f0 DN |
512 | |
513 | /* If the statement has volatile operands, it won't fold to a | |
514 | constant value. */ | |
726a989a | 515 | if (gimple_has_volatile_ops (stmt)) |
0bca51f0 DN |
516 | return VARYING; |
517 | ||
518 | /* If we are not doing store-ccp, statements with loads | |
519 | and/or stores will never fold into a constant. */ | |
dce2b2f6 | 520 | if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)) |
750628d8 | 521 | return VARYING; |
6de9cd9a | 522 | |
726a989a RB |
523 | /* Note that only a GIMPLE_SINGLE_RHS assignment can satisfy |
524 | is_gimple_min_invariant, so we do not consider calls or | |
525 | other forms of assignment. */ | |
174ef36d | 526 | if (gimple_assign_single_p (stmt) |
726a989a RB |
527 | && is_gimple_min_invariant (gimple_assign_rhs1 (stmt))) |
528 | return CONSTANT; | |
0bca51f0 | 529 | |
726a989a RB |
530 | if (code == GIMPLE_COND |
531 | && is_gimple_min_invariant (gimple_cond_lhs (stmt)) | |
532 | && is_gimple_min_invariant (gimple_cond_rhs (stmt))) | |
a318e3ac SB |
533 | return CONSTANT; |
534 | ||
726a989a RB |
535 | if (code == GIMPLE_SWITCH |
536 | && is_gimple_min_invariant (gimple_switch_index (stmt))) | |
537 | return CONSTANT; | |
538 | ||
539 | /* Arrive here for more complex cases. */ | |
540 | ||
106dec71 | 541 | has_constant_operand = false; |
7f879c96 RG |
542 | has_undefined_operand = false; |
543 | all_undefined_operands = true; | |
106dec71 | 544 | FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE | SSA_OP_VUSE) |
750628d8 | 545 | { |
106dec71 | 546 | prop_value_t *val = get_value (use); |
750628d8 | 547 | |
106dec71 | 548 | if (val->lattice_val == UNDEFINED) |
7f879c96 RG |
549 | has_undefined_operand = true; |
550 | else | |
551 | all_undefined_operands = false; | |
0bca51f0 | 552 | |
750628d8 | 553 | if (val->lattice_val == CONSTANT) |
106dec71 | 554 | has_constant_operand = true; |
6de9cd9a | 555 | } |
750628d8 | 556 | |
7f879c96 RG |
557 | /* If the operation combines operands like COMPLEX_EXPR make sure to |
558 | not mark the result UNDEFINED if only one part of the result is | |
559 | undefined. */ | |
726a989a | 560 | if (has_undefined_operand && all_undefined_operands) |
7f879c96 | 561 | return UNDEFINED; |
726a989a | 562 | else if (code == GIMPLE_ASSIGN && has_undefined_operand) |
7f879c96 | 563 | { |
726a989a | 564 | switch (gimple_assign_rhs_code (stmt)) |
7f879c96 RG |
565 | { |
566 | /* Unary operators are handled with all_undefined_operands. */ | |
567 | case PLUS_EXPR: | |
568 | case MINUS_EXPR: | |
7f879c96 | 569 | case POINTER_PLUS_EXPR: |
7f879c96 RG |
570 | /* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected. |
571 | Not bitwise operators, one VARYING operand may specify the | |
572 | result completely. Not logical operators for the same reason. | |
0cedb9e9 RG |
573 | Not COMPLEX_EXPR as one VARYING operand makes the result partly |
574 | not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because | |
575 | the undefined operand may be promoted. */ | |
7f879c96 RG |
576 | return UNDEFINED; |
577 | ||
578 | default: | |
579 | ; | |
580 | } | |
581 | } | |
582 | /* If there was an UNDEFINED operand but the result may be not UNDEFINED | |
583 | fall back to VARYING even if there were CONSTANT operands. */ | |
584 | if (has_undefined_operand) | |
585 | return VARYING; | |
586 | ||
106dec71 ZD |
587 | if (has_constant_operand |
588 | /* We do not consider virtual operands here -- load from read-only | |
589 | memory may have only VARYING virtual operands, but still be | |
590 | constant. */ | |
591 | || ZERO_SSA_OPERANDS (stmt, SSA_OP_USE)) | |
0bca51f0 DN |
592 | return CONSTANT; |
593 | ||
106dec71 | 594 | return VARYING; |
6de9cd9a DN |
595 | } |
596 | ||
106dec71 ZD |
597 | /* Returns true if STMT cannot be constant. */ |
598 | ||
599 | static bool | |
726a989a | 600 | surely_varying_stmt_p (gimple stmt) |
106dec71 ZD |
601 | { |
602 | /* If the statement has operands that we cannot handle, it cannot be | |
603 | constant. */ | |
726a989a | 604 | if (gimple_has_volatile_ops (stmt)) |
106dec71 ZD |
605 | return true; |
606 | ||
607 | if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)) | |
dce2b2f6 | 608 | return true; |
106dec71 | 609 | |
174ef36d RG |
610 | /* If it is a call and does not return a value or is not a |
611 | builtin and not an indirect call, it is varying. */ | |
726a989a | 612 | if (is_gimple_call (stmt)) |
174ef36d RG |
613 | { |
614 | tree fndecl; | |
615 | if (!gimple_call_lhs (stmt) | |
616 | || ((fndecl = gimple_call_fndecl (stmt)) != NULL_TREE | |
99f536cc | 617 | && !DECL_BUILT_IN (fndecl))) |
174ef36d RG |
618 | return true; |
619 | } | |
106dec71 ZD |
620 | |
621 | /* Anything other than assignments and conditional jumps are not | |
622 | interesting for CCP. */ | |
726a989a | 623 | if (gimple_code (stmt) != GIMPLE_ASSIGN |
174ef36d RG |
624 | && gimple_code (stmt) != GIMPLE_COND |
625 | && gimple_code (stmt) != GIMPLE_SWITCH | |
626 | && gimple_code (stmt) != GIMPLE_CALL) | |
106dec71 ZD |
627 | return true; |
628 | ||
629 | return false; | |
630 | } | |
6de9cd9a | 631 | |
750628d8 | 632 | /* Initialize local data structures for CCP. */ |
6de9cd9a DN |
633 | |
634 | static void | |
750628d8 | 635 | ccp_initialize (void) |
6de9cd9a | 636 | { |
750628d8 | 637 | basic_block bb; |
6de9cd9a | 638 | |
b9eae1a9 | 639 | const_val = XCNEWVEC (prop_value_t, num_ssa_names); |
6de9cd9a | 640 | |
750628d8 DN |
641 | /* Initialize simulation flags for PHI nodes and statements. */ |
642 | FOR_EACH_BB (bb) | |
6de9cd9a | 643 | { |
726a989a | 644 | gimple_stmt_iterator i; |
6de9cd9a | 645 | |
726a989a | 646 | for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) |
750628d8 | 647 | { |
726a989a | 648 | gimple stmt = gsi_stmt (i); |
106dec71 | 649 | bool is_varying = surely_varying_stmt_p (stmt); |
6de9cd9a | 650 | |
106dec71 | 651 | if (is_varying) |
750628d8 | 652 | { |
0bca51f0 DN |
653 | tree def; |
654 | ssa_op_iter iter; | |
655 | ||
656 | /* If the statement will not produce a constant, mark | |
657 | all its outputs VARYING. */ | |
658 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) | |
106dec71 ZD |
659 | { |
660 | if (is_varying) | |
661 | set_value_varying (def); | |
662 | } | |
750628d8 | 663 | } |
726a989a | 664 | prop_set_simulate_again (stmt, !is_varying); |
750628d8 | 665 | } |
6de9cd9a DN |
666 | } |
667 | ||
726a989a RB |
668 | /* Now process PHI nodes. We never clear the simulate_again flag on |
669 | phi nodes, since we do not know which edges are executable yet, | |
670 | except for phi nodes for virtual operands when we do not do store ccp. */ | |
750628d8 | 671 | FOR_EACH_BB (bb) |
6de9cd9a | 672 | { |
726a989a | 673 | gimple_stmt_iterator i; |
750628d8 | 674 | |
726a989a RB |
675 | for (i = gsi_start_phis (bb); !gsi_end_p (i); gsi_next (&i)) |
676 | { | |
677 | gimple phi = gsi_stmt (i); | |
678 | ||
dce2b2f6 | 679 | if (!is_gimple_reg (gimple_phi_result (phi))) |
726a989a | 680 | prop_set_simulate_again (phi, false); |
106dec71 | 681 | else |
726a989a | 682 | prop_set_simulate_again (phi, true); |
750628d8 | 683 | } |
6de9cd9a | 684 | } |
750628d8 | 685 | } |
6de9cd9a | 686 | |
6de9cd9a | 687 | |
0bca51f0 | 688 | /* Do final substitution of propagated values, cleanup the flowgraph and |
3253eafb | 689 | free allocated storage. |
6de9cd9a | 690 | |
3253eafb JH |
691 | Return TRUE when something was optimized. */ |
692 | ||
693 | static bool | |
0bca51f0 | 694 | ccp_finalize (void) |
6de9cd9a | 695 | { |
0bca51f0 | 696 | /* Perform substitutions based on the known constant values. */ |
3253eafb | 697 | bool something_changed = substitute_and_fold (const_val, false); |
6de9cd9a | 698 | |
0bca51f0 | 699 | free (const_val); |
ed97ddc6 | 700 | const_val = NULL; |
3253eafb | 701 | return something_changed;; |
6de9cd9a DN |
702 | } |
703 | ||
704 | ||
0bca51f0 DN |
705 | /* Compute the meet operator between *VAL1 and *VAL2. Store the result |
706 | in VAL1. | |
707 | ||
708 | any M UNDEFINED = any | |
0bca51f0 DN |
709 | any M VARYING = VARYING |
710 | Ci M Cj = Ci if (i == j) | |
711 | Ci M Cj = VARYING if (i != j) | |
106dec71 | 712 | */ |
6de9cd9a DN |
713 | |
714 | static void | |
0bca51f0 | 715 | ccp_lattice_meet (prop_value_t *val1, prop_value_t *val2) |
6de9cd9a | 716 | { |
0bca51f0 | 717 | if (val1->lattice_val == UNDEFINED) |
6de9cd9a | 718 | { |
0bca51f0 DN |
719 | /* UNDEFINED M any = any */ |
720 | *val1 = *val2; | |
750628d8 | 721 | } |
0bca51f0 | 722 | else if (val2->lattice_val == UNDEFINED) |
195da47b | 723 | { |
0bca51f0 DN |
724 | /* any M UNDEFINED = any |
725 | Nothing to do. VAL1 already contains the value we want. */ | |
726 | ; | |
195da47b | 727 | } |
0bca51f0 DN |
728 | else if (val1->lattice_val == VARYING |
729 | || val2->lattice_val == VARYING) | |
750628d8 | 730 | { |
0bca51f0 DN |
731 | /* any M VARYING = VARYING. */ |
732 | val1->lattice_val = VARYING; | |
733 | val1->value = NULL_TREE; | |
750628d8 | 734 | } |
0bca51f0 DN |
735 | else if (val1->lattice_val == CONSTANT |
736 | && val2->lattice_val == CONSTANT | |
dce2b2f6 | 737 | && simple_cst_equal (val1->value, val2->value) == 1) |
750628d8 | 738 | { |
0bca51f0 DN |
739 | /* Ci M Cj = Ci if (i == j) |
740 | Ci M Cj = VARYING if (i != j) | |
741 | ||
742 | If these two values come from memory stores, make sure that | |
743 | they come from the same memory reference. */ | |
744 | val1->lattice_val = CONSTANT; | |
745 | val1->value = val1->value; | |
750628d8 DN |
746 | } |
747 | else | |
748 | { | |
0bca51f0 DN |
749 | /* Any other combination is VARYING. */ |
750 | val1->lattice_val = VARYING; | |
751 | val1->value = NULL_TREE; | |
750628d8 | 752 | } |
6de9cd9a DN |
753 | } |
754 | ||
755 | ||
750628d8 DN |
756 | /* Loop through the PHI_NODE's parameters for BLOCK and compare their |
757 | lattice values to determine PHI_NODE's lattice value. The value of a | |
0bca51f0 | 758 | PHI node is determined calling ccp_lattice_meet with all the arguments |
750628d8 | 759 | of the PHI node that are incoming via executable edges. */ |
6de9cd9a | 760 | |
750628d8 | 761 | static enum ssa_prop_result |
726a989a | 762 | ccp_visit_phi_node (gimple phi) |
6de9cd9a | 763 | { |
726a989a | 764 | unsigned i; |
0bca51f0 | 765 | prop_value_t *old_val, new_val; |
6de9cd9a | 766 | |
750628d8 | 767 | if (dump_file && (dump_flags & TDF_DETAILS)) |
6de9cd9a | 768 | { |
750628d8 | 769 | fprintf (dump_file, "\nVisiting PHI node: "); |
726a989a | 770 | print_gimple_stmt (dump_file, phi, 0, dump_flags); |
6de9cd9a | 771 | } |
6de9cd9a | 772 | |
726a989a | 773 | old_val = get_value (gimple_phi_result (phi)); |
750628d8 DN |
774 | switch (old_val->lattice_val) |
775 | { | |
776 | case VARYING: | |
0bca51f0 | 777 | return SSA_PROP_VARYING; |
6de9cd9a | 778 | |
750628d8 DN |
779 | case CONSTANT: |
780 | new_val = *old_val; | |
781 | break; | |
6de9cd9a | 782 | |
750628d8 | 783 | case UNDEFINED: |
750628d8 | 784 | new_val.lattice_val = UNDEFINED; |
0bca51f0 | 785 | new_val.value = NULL_TREE; |
750628d8 | 786 | break; |
6de9cd9a | 787 | |
750628d8 | 788 | default: |
1e128c5f | 789 | gcc_unreachable (); |
750628d8 | 790 | } |
6de9cd9a | 791 | |
726a989a | 792 | for (i = 0; i < gimple_phi_num_args (phi); i++) |
750628d8 | 793 | { |
0bca51f0 DN |
794 | /* Compute the meet operator over all the PHI arguments flowing |
795 | through executable edges. */ | |
726a989a | 796 | edge e = gimple_phi_arg_edge (phi, i); |
6de9cd9a | 797 | |
750628d8 DN |
798 | if (dump_file && (dump_flags & TDF_DETAILS)) |
799 | { | |
800 | fprintf (dump_file, | |
801 | "\n Argument #%d (%d -> %d %sexecutable)\n", | |
802 | i, e->src->index, e->dest->index, | |
803 | (e->flags & EDGE_EXECUTABLE) ? "" : "not "); | |
804 | } | |
805 | ||
806 | /* If the incoming edge is executable, Compute the meet operator for | |
807 | the existing value of the PHI node and the current PHI argument. */ | |
808 | if (e->flags & EDGE_EXECUTABLE) | |
809 | { | |
726a989a | 810 | tree arg = gimple_phi_arg (phi, i)->def; |
0bca51f0 | 811 | prop_value_t arg_val; |
6de9cd9a | 812 | |
0bca51f0 | 813 | if (is_gimple_min_invariant (arg)) |
750628d8 | 814 | { |
0bca51f0 DN |
815 | arg_val.lattice_val = CONSTANT; |
816 | arg_val.value = arg; | |
750628d8 DN |
817 | } |
818 | else | |
106dec71 | 819 | arg_val = *(get_value (arg)); |
6de9cd9a | 820 | |
0bca51f0 | 821 | ccp_lattice_meet (&new_val, &arg_val); |
6de9cd9a | 822 | |
750628d8 DN |
823 | if (dump_file && (dump_flags & TDF_DETAILS)) |
824 | { | |
825 | fprintf (dump_file, "\t"); | |
0bca51f0 DN |
826 | print_generic_expr (dump_file, arg, dump_flags); |
827 | dump_lattice_value (dump_file, "\tValue: ", arg_val); | |
750628d8 DN |
828 | fprintf (dump_file, "\n"); |
829 | } | |
6de9cd9a | 830 | |
750628d8 DN |
831 | if (new_val.lattice_val == VARYING) |
832 | break; | |
833 | } | |
834 | } | |
6de9cd9a DN |
835 | |
836 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
750628d8 DN |
837 | { |
838 | dump_lattice_value (dump_file, "\n PHI node value: ", new_val); | |
839 | fprintf (dump_file, "\n\n"); | |
840 | } | |
841 | ||
106dec71 | 842 | /* Make the transition to the new value. */ |
726a989a | 843 | if (set_lattice_value (gimple_phi_result (phi), new_val)) |
750628d8 DN |
844 | { |
845 | if (new_val.lattice_val == VARYING) | |
846 | return SSA_PROP_VARYING; | |
847 | else | |
848 | return SSA_PROP_INTERESTING; | |
849 | } | |
850 | else | |
851 | return SSA_PROP_NOT_INTERESTING; | |
6de9cd9a DN |
852 | } |
853 | ||
f7c0ffb4 RG |
854 | /* Return true if we may propagate the address expression ADDR into the |
855 | dereference DEREF and cancel them. */ | |
856 | ||
857 | bool | |
858 | may_propagate_address_into_dereference (tree addr, tree deref) | |
859 | { | |
860 | gcc_assert (INDIRECT_REF_P (deref) | |
861 | && TREE_CODE (addr) == ADDR_EXPR); | |
862 | ||
863 | /* If the address is invariant then we do not need to preserve restrict | |
864 | qualifications. But we do need to preserve volatile qualifiers until | |
865 | we can annotate the folded dereference itself properly. */ | |
866 | if (is_gimple_min_invariant (addr) | |
867 | && (!TREE_THIS_VOLATILE (deref) | |
868 | || TYPE_VOLATILE (TREE_TYPE (addr)))) | |
869 | return useless_type_conversion_p (TREE_TYPE (deref), | |
870 | TREE_TYPE (TREE_OPERAND (addr, 0))); | |
871 | ||
872 | /* Else both the address substitution and the folding must result in | |
873 | a valid useless type conversion sequence. */ | |
874 | return (useless_type_conversion_p (TREE_TYPE (TREE_OPERAND (deref, 0)), | |
875 | TREE_TYPE (addr)) | |
876 | && useless_type_conversion_p (TREE_TYPE (deref), | |
877 | TREE_TYPE (TREE_OPERAND (addr, 0)))); | |
878 | } | |
6de9cd9a | 879 | |
750628d8 DN |
880 | /* CCP specific front-end to the non-destructive constant folding |
881 | routines. | |
6de9cd9a DN |
882 | |
883 | Attempt to simplify the RHS of STMT knowing that one or more | |
884 | operands are constants. | |
885 | ||
886 | If simplification is possible, return the simplified RHS, | |
726a989a | 887 | otherwise return the original RHS or NULL_TREE. */ |
6de9cd9a DN |
888 | |
889 | static tree | |
726a989a | 890 | ccp_fold (gimple stmt) |
6de9cd9a | 891 | { |
726a989a | 892 | switch (gimple_code (stmt)) |
0bca51f0 | 893 | { |
726a989a RB |
894 | case GIMPLE_ASSIGN: |
895 | { | |
896 | enum tree_code subcode = gimple_assign_rhs_code (stmt); | |
897 | ||
898 | switch (get_gimple_rhs_class (subcode)) | |
899 | { | |
900 | case GIMPLE_SINGLE_RHS: | |
901 | { | |
902 | tree rhs = gimple_assign_rhs1 (stmt); | |
903 | enum tree_code_class kind = TREE_CODE_CLASS (subcode); | |
904 | ||
905 | if (TREE_CODE (rhs) == SSA_NAME) | |
906 | { | |
907 | /* If the RHS is an SSA_NAME, return its known constant value, | |
908 | if any. */ | |
909 | return get_value (rhs)->value; | |
910 | } | |
911 | /* Handle propagating invariant addresses into address operations. | |
912 | The folding we do here matches that in tree-ssa-forwprop.c. */ | |
913 | else if (TREE_CODE (rhs) == ADDR_EXPR) | |
914 | { | |
915 | tree *base; | |
916 | base = &TREE_OPERAND (rhs, 0); | |
917 | while (handled_component_p (*base)) | |
918 | base = &TREE_OPERAND (*base, 0); | |
919 | if (TREE_CODE (*base) == INDIRECT_REF | |
920 | && TREE_CODE (TREE_OPERAND (*base, 0)) == SSA_NAME) | |
921 | { | |
922 | prop_value_t *val = get_value (TREE_OPERAND (*base, 0)); | |
923 | if (val->lattice_val == CONSTANT | |
924 | && TREE_CODE (val->value) == ADDR_EXPR | |
f7c0ffb4 RG |
925 | && may_propagate_address_into_dereference |
926 | (val->value, *base)) | |
726a989a RB |
927 | { |
928 | /* We need to return a new tree, not modify the IL | |
929 | or share parts of it. So play some tricks to | |
930 | avoid manually building it. */ | |
931 | tree ret, save = *base; | |
932 | *base = TREE_OPERAND (val->value, 0); | |
933 | ret = unshare_expr (rhs); | |
934 | recompute_tree_invariant_for_addr_expr (ret); | |
935 | *base = save; | |
936 | return ret; | |
937 | } | |
938 | } | |
939 | } | |
6de9cd9a | 940 | |
726a989a | 941 | if (kind == tcc_reference) |
c76a1f18 RG |
942 | { |
943 | if (TREE_CODE (rhs) == VIEW_CONVERT_EXPR | |
944 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME) | |
945 | { | |
946 | prop_value_t *val = get_value (TREE_OPERAND (rhs, 0)); | |
947 | if (val->lattice_val == CONSTANT) | |
948 | return fold_unary (VIEW_CONVERT_EXPR, | |
949 | TREE_TYPE (rhs), val->value); | |
950 | } | |
951 | return fold_const_aggregate_ref (rhs); | |
952 | } | |
726a989a RB |
953 | else if (kind == tcc_declaration) |
954 | return get_symbol_constant_value (rhs); | |
955 | return rhs; | |
956 | } | |
957 | ||
958 | case GIMPLE_UNARY_RHS: | |
959 | { | |
960 | /* Handle unary operators that can appear in GIMPLE form. | |
961 | Note that we know the single operand must be a constant, | |
962 | so this should almost always return a simplified RHS. */ | |
963 | tree lhs = gimple_assign_lhs (stmt); | |
964 | tree op0 = gimple_assign_rhs1 (stmt); | |
ff8b183b | 965 | tree res; |
726a989a RB |
966 | |
967 | /* Simplify the operand down to a constant. */ | |
968 | if (TREE_CODE (op0) == SSA_NAME) | |
969 | { | |
970 | prop_value_t *val = get_value (op0); | |
971 | if (val->lattice_val == CONSTANT) | |
972 | op0 = get_value (op0)->value; | |
973 | } | |
974 | ||
975 | /* Conversions are useless for CCP purposes if they are | |
976 | value-preserving. Thus the restrictions that | |
977 | useless_type_conversion_p places for pointer type conversions | |
978 | do not apply here. Substitution later will only substitute to | |
979 | allowed places. */ | |
1a87cf0c | 980 | if (CONVERT_EXPR_CODE_P (subcode) |
99f536cc RG |
981 | && POINTER_TYPE_P (TREE_TYPE (lhs)) |
982 | && POINTER_TYPE_P (TREE_TYPE (op0)) | |
983 | /* Do not allow differences in volatile qualification | |
984 | as this might get us confused as to whether a | |
985 | propagation destination statement is volatile | |
986 | or not. See PR36988. */ | |
987 | && (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (lhs))) | |
988 | == TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (op0))))) | |
989 | { | |
990 | tree tem; | |
991 | /* Still try to generate a constant of correct type. */ | |
992 | if (!useless_type_conversion_p (TREE_TYPE (lhs), | |
993 | TREE_TYPE (op0)) | |
994 | && ((tem = maybe_fold_offset_to_address | |
995 | (op0, integer_zero_node, TREE_TYPE (lhs))) | |
996 | != NULL_TREE)) | |
997 | return tem; | |
998 | return op0; | |
999 | } | |
726a989a | 1000 | |
ff8b183b RG |
1001 | res = fold_unary (subcode, gimple_expr_type (stmt), op0); |
1002 | ||
1003 | /* If the operation was a conversion do _not_ mark a | |
1004 | resulting constant with TREE_OVERFLOW if the original | |
1005 | constant was not. These conversions have implementation | |
1006 | defined behavior and retaining the TREE_OVERFLOW flag | |
1007 | here would confuse later passes such as VRP. */ | |
1008 | if (res | |
1009 | && TREE_CODE (res) == INTEGER_CST | |
1010 | && TREE_CODE (op0) == INTEGER_CST | |
1011 | && CONVERT_EXPR_CODE_P (subcode)) | |
1012 | TREE_OVERFLOW (res) = TREE_OVERFLOW (op0); | |
1013 | ||
1014 | return res; | |
1015 | } | |
726a989a RB |
1016 | |
1017 | case GIMPLE_BINARY_RHS: | |
1018 | { | |
1019 | /* Handle binary operators that can appear in GIMPLE form. */ | |
1020 | tree op0 = gimple_assign_rhs1 (stmt); | |
1021 | tree op1 = gimple_assign_rhs2 (stmt); | |
1022 | ||
1023 | /* Simplify the operands down to constants when appropriate. */ | |
1024 | if (TREE_CODE (op0) == SSA_NAME) | |
1025 | { | |
1026 | prop_value_t *val = get_value (op0); | |
1027 | if (val->lattice_val == CONSTANT) | |
1028 | op0 = val->value; | |
1029 | } | |
1030 | ||
1031 | if (TREE_CODE (op1) == SSA_NAME) | |
1032 | { | |
1033 | prop_value_t *val = get_value (op1); | |
1034 | if (val->lattice_val == CONSTANT) | |
1035 | op1 = val->value; | |
1036 | } | |
1037 | ||
99f536cc RG |
1038 | /* Fold &foo + CST into an invariant reference if possible. */ |
1039 | if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR | |
1040 | && TREE_CODE (op0) == ADDR_EXPR | |
1041 | && TREE_CODE (op1) == INTEGER_CST) | |
1042 | { | |
1043 | tree lhs = gimple_assign_lhs (stmt); | |
1044 | tree tem = maybe_fold_offset_to_address (op0, op1, | |
1045 | TREE_TYPE (lhs)); | |
1046 | if (tem != NULL_TREE) | |
1047 | return tem; | |
1048 | } | |
1049 | ||
726a989a RB |
1050 | return fold_binary (subcode, gimple_expr_type (stmt), op0, op1); |
1051 | } | |
1052 | ||
1053 | default: | |
1054 | gcc_unreachable (); | |
1055 | } | |
1056 | } | |
1057 | break; | |
6de9cd9a | 1058 | |
726a989a | 1059 | case GIMPLE_CALL: |
174ef36d RG |
1060 | { |
1061 | tree fn = gimple_call_fn (stmt); | |
1062 | prop_value_t *val; | |
1063 | ||
1064 | if (TREE_CODE (fn) == SSA_NAME) | |
1065 | { | |
1066 | val = get_value (fn); | |
1067 | if (val->lattice_val == CONSTANT) | |
1068 | fn = val->value; | |
1069 | } | |
1070 | if (TREE_CODE (fn) == ADDR_EXPR | |
a135b1c4 | 1071 | && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL |
174ef36d RG |
1072 | && DECL_BUILT_IN (TREE_OPERAND (fn, 0))) |
1073 | { | |
1074 | tree *args = XALLOCAVEC (tree, gimple_call_num_args (stmt)); | |
1075 | tree call, retval; | |
1076 | unsigned i; | |
1077 | for (i = 0; i < gimple_call_num_args (stmt); ++i) | |
1078 | { | |
1079 | args[i] = gimple_call_arg (stmt, i); | |
1080 | if (TREE_CODE (args[i]) == SSA_NAME) | |
1081 | { | |
1082 | val = get_value (args[i]); | |
1083 | if (val->lattice_val == CONSTANT) | |
1084 | args[i] = val->value; | |
1085 | } | |
1086 | } | |
1087 | call = build_call_array (gimple_call_return_type (stmt), | |
1088 | fn, gimple_call_num_args (stmt), args); | |
1089 | retval = fold_call_expr (call, false); | |
1090 | if (retval) | |
1091 | /* fold_call_expr wraps the result inside a NOP_EXPR. */ | |
1092 | STRIP_NOPS (retval); | |
1093 | return retval; | |
1094 | } | |
1095 | return NULL_TREE; | |
1096 | } | |
6de9cd9a | 1097 | |
726a989a RB |
1098 | case GIMPLE_COND: |
1099 | { | |
1100 | /* Handle comparison operators that can appear in GIMPLE form. */ | |
1101 | tree op0 = gimple_cond_lhs (stmt); | |
1102 | tree op1 = gimple_cond_rhs (stmt); | |
1103 | enum tree_code code = gimple_cond_code (stmt); | |
1104 | ||
1105 | /* Simplify the operands down to constants when appropriate. */ | |
1106 | if (TREE_CODE (op0) == SSA_NAME) | |
1107 | { | |
1108 | prop_value_t *val = get_value (op0); | |
1109 | if (val->lattice_val == CONSTANT) | |
1110 | op0 = val->value; | |
1111 | } | |
1112 | ||
1113 | if (TREE_CODE (op1) == SSA_NAME) | |
1114 | { | |
1115 | prop_value_t *val = get_value (op1); | |
1116 | if (val->lattice_val == CONSTANT) | |
1117 | op1 = val->value; | |
1118 | } | |
1119 | ||
1120 | return fold_binary (code, boolean_type_node, op0, op1); | |
1121 | } | |
6de9cd9a | 1122 | |
726a989a RB |
1123 | case GIMPLE_SWITCH: |
1124 | { | |
1125 | tree rhs = gimple_switch_index (stmt); | |
87e1e42b | 1126 | |
726a989a RB |
1127 | if (TREE_CODE (rhs) == SSA_NAME) |
1128 | { | |
1129 | /* If the RHS is an SSA_NAME, return its known constant value, | |
1130 | if any. */ | |
1131 | return get_value (rhs)->value; | |
1132 | } | |
87e1e42b | 1133 | |
726a989a RB |
1134 | return rhs; |
1135 | } | |
00d382a8 | 1136 | |
726a989a RB |
1137 | default: |
1138 | gcc_unreachable (); | |
6de9cd9a | 1139 | } |
6de9cd9a DN |
1140 | } |
1141 | ||
1142 | ||
ae3df618 SB |
1143 | /* Return the tree representing the element referenced by T if T is an |
1144 | ARRAY_REF or COMPONENT_REF into constant aggregates. Return | |
1145 | NULL_TREE otherwise. */ | |
1146 | ||
ed97ddc6 | 1147 | tree |
ae3df618 SB |
1148 | fold_const_aggregate_ref (tree t) |
1149 | { | |
1150 | prop_value_t *value; | |
4038c495 GB |
1151 | tree base, ctor, idx, field; |
1152 | unsigned HOST_WIDE_INT cnt; | |
1153 | tree cfield, cval; | |
ae3df618 SB |
1154 | |
1155 | switch (TREE_CODE (t)) | |
1156 | { | |
1157 | case ARRAY_REF: | |
1158 | /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its | |
1159 | DECL_INITIAL. If BASE is a nested reference into another | |
1160 | ARRAY_REF or COMPONENT_REF, make a recursive call to resolve | |
1161 | the inner reference. */ | |
1162 | base = TREE_OPERAND (t, 0); | |
1163 | switch (TREE_CODE (base)) | |
1164 | { | |
1165 | case VAR_DECL: | |
1166 | if (!TREE_READONLY (base) | |
1167 | || TREE_CODE (TREE_TYPE (base)) != ARRAY_TYPE | |
1168 | || !targetm.binds_local_p (base)) | |
1169 | return NULL_TREE; | |
1170 | ||
1171 | ctor = DECL_INITIAL (base); | |
1172 | break; | |
1173 | ||
1174 | case ARRAY_REF: | |
1175 | case COMPONENT_REF: | |
1176 | ctor = fold_const_aggregate_ref (base); | |
1177 | break; | |
1178 | ||
87e1e42b RG |
1179 | case STRING_CST: |
1180 | case CONSTRUCTOR: | |
1181 | ctor = base; | |
1182 | break; | |
1183 | ||
ae3df618 SB |
1184 | default: |
1185 | return NULL_TREE; | |
1186 | } | |
1187 | ||
1188 | if (ctor == NULL_TREE | |
faaf1436 RG |
1189 | || (TREE_CODE (ctor) != CONSTRUCTOR |
1190 | && TREE_CODE (ctor) != STRING_CST) | |
ae3df618 SB |
1191 | || !TREE_STATIC (ctor)) |
1192 | return NULL_TREE; | |
1193 | ||
1194 | /* Get the index. If we have an SSA_NAME, try to resolve it | |
1195 | with the current lattice value for the SSA_NAME. */ | |
1196 | idx = TREE_OPERAND (t, 1); | |
1197 | switch (TREE_CODE (idx)) | |
1198 | { | |
1199 | case SSA_NAME: | |
106dec71 | 1200 | if ((value = get_value (idx)) |
ae3df618 SB |
1201 | && value->lattice_val == CONSTANT |
1202 | && TREE_CODE (value->value) == INTEGER_CST) | |
1203 | idx = value->value; | |
1204 | else | |
1205 | return NULL_TREE; | |
1206 | break; | |
1207 | ||
1208 | case INTEGER_CST: | |
1209 | break; | |
1210 | ||
1211 | default: | |
1212 | return NULL_TREE; | |
1213 | } | |
1214 | ||
faaf1436 RG |
1215 | /* Fold read from constant string. */ |
1216 | if (TREE_CODE (ctor) == STRING_CST) | |
1217 | { | |
1218 | if ((TYPE_MODE (TREE_TYPE (t)) | |
1219 | == TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1220 | && (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1221 | == MODE_INT) | |
1222 | && GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) == 1 | |
1223 | && compare_tree_int (idx, TREE_STRING_LENGTH (ctor)) < 0) | |
0c4d4efb DJ |
1224 | return build_int_cst_type (TREE_TYPE (t), |
1225 | (TREE_STRING_POINTER (ctor) | |
1226 | [TREE_INT_CST_LOW (idx)])); | |
faaf1436 RG |
1227 | return NULL_TREE; |
1228 | } | |
1229 | ||
ae3df618 | 1230 | /* Whoo-hoo! I'll fold ya baby. Yeah! */ |
4038c495 GB |
1231 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) |
1232 | if (tree_int_cst_equal (cfield, idx)) | |
62bc00e2 RG |
1233 | { |
1234 | STRIP_USELESS_TYPE_CONVERSION (cval); | |
1235 | return cval; | |
1236 | } | |
ae3df618 SB |
1237 | break; |
1238 | ||
1239 | case COMPONENT_REF: | |
1240 | /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its | |
1241 | DECL_INITIAL. If BASE is a nested reference into another | |
1242 | ARRAY_REF or COMPONENT_REF, make a recursive call to resolve | |
1243 | the inner reference. */ | |
1244 | base = TREE_OPERAND (t, 0); | |
1245 | switch (TREE_CODE (base)) | |
1246 | { | |
1247 | case VAR_DECL: | |
1248 | if (!TREE_READONLY (base) | |
1249 | || TREE_CODE (TREE_TYPE (base)) != RECORD_TYPE | |
1250 | || !targetm.binds_local_p (base)) | |
1251 | return NULL_TREE; | |
1252 | ||
1253 | ctor = DECL_INITIAL (base); | |
1254 | break; | |
1255 | ||
1256 | case ARRAY_REF: | |
1257 | case COMPONENT_REF: | |
1258 | ctor = fold_const_aggregate_ref (base); | |
1259 | break; | |
1260 | ||
1261 | default: | |
1262 | return NULL_TREE; | |
1263 | } | |
1264 | ||
1265 | if (ctor == NULL_TREE | |
1266 | || TREE_CODE (ctor) != CONSTRUCTOR | |
1267 | || !TREE_STATIC (ctor)) | |
1268 | return NULL_TREE; | |
1269 | ||
1270 | field = TREE_OPERAND (t, 1); | |
1271 | ||
4038c495 GB |
1272 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) |
1273 | if (cfield == field | |
ae3df618 | 1274 | /* FIXME: Handle bit-fields. */ |
4038c495 | 1275 | && ! DECL_BIT_FIELD (cfield)) |
62bc00e2 RG |
1276 | { |
1277 | STRIP_USELESS_TYPE_CONVERSION (cval); | |
1278 | return cval; | |
1279 | } | |
ae3df618 SB |
1280 | break; |
1281 | ||
1ebd8d9a SB |
1282 | case REALPART_EXPR: |
1283 | case IMAGPART_EXPR: | |
1284 | { | |
1285 | tree c = fold_const_aggregate_ref (TREE_OPERAND (t, 0)); | |
1286 | if (c && TREE_CODE (c) == COMPLEX_CST) | |
1287 | return fold_build1 (TREE_CODE (t), TREE_TYPE (t), c); | |
1288 | break; | |
1289 | } | |
87e1e42b RG |
1290 | |
1291 | case INDIRECT_REF: | |
1292 | { | |
1293 | tree base = TREE_OPERAND (t, 0); | |
1294 | if (TREE_CODE (base) == SSA_NAME | |
1295 | && (value = get_value (base)) | |
1296 | && value->lattice_val == CONSTANT | |
1297 | && TREE_CODE (value->value) == ADDR_EXPR) | |
1298 | return fold_const_aggregate_ref (TREE_OPERAND (value->value, 0)); | |
1299 | break; | |
1300 | } | |
1301 | ||
ae3df618 SB |
1302 | default: |
1303 | break; | |
1304 | } | |
1305 | ||
1306 | return NULL_TREE; | |
1307 | } | |
726a989a RB |
1308 | |
1309 | /* Evaluate statement STMT. | |
1310 | Valid only for assignments, calls, conditionals, and switches. */ | |
6de9cd9a | 1311 | |
0bca51f0 | 1312 | static prop_value_t |
726a989a | 1313 | evaluate_stmt (gimple stmt) |
6de9cd9a | 1314 | { |
0bca51f0 | 1315 | prop_value_t val; |
faaf1436 | 1316 | tree simplified = NULL_TREE; |
0bca51f0 | 1317 | ccp_lattice_t likelyvalue = likely_value (stmt); |
6ac01510 | 1318 | bool is_constant; |
0bca51f0 | 1319 | |
6ac01510 ILT |
1320 | fold_defer_overflow_warnings (); |
1321 | ||
6de9cd9a DN |
1322 | /* If the statement is likely to have a CONSTANT result, then try |
1323 | to fold the statement to determine the constant value. */ | |
726a989a RB |
1324 | /* FIXME. This is the only place that we call ccp_fold. |
1325 | Since likely_value never returns CONSTANT for calls, we will | |
1326 | not attempt to fold them, including builtins that may profit. */ | |
6de9cd9a DN |
1327 | if (likelyvalue == CONSTANT) |
1328 | simplified = ccp_fold (stmt); | |
1329 | /* If the statement is likely to have a VARYING result, then do not | |
1330 | bother folding the statement. */ | |
87e1e42b | 1331 | else if (likelyvalue == VARYING) |
726a989a | 1332 | { |
e0c68ce9 | 1333 | enum gimple_code code = gimple_code (stmt); |
726a989a RB |
1334 | if (code == GIMPLE_ASSIGN) |
1335 | { | |
1336 | enum tree_code subcode = gimple_assign_rhs_code (stmt); | |
1337 | ||
1338 | /* Other cases cannot satisfy is_gimple_min_invariant | |
1339 | without folding. */ | |
1340 | if (get_gimple_rhs_class (subcode) == GIMPLE_SINGLE_RHS) | |
1341 | simplified = gimple_assign_rhs1 (stmt); | |
1342 | } | |
1343 | else if (code == GIMPLE_SWITCH) | |
1344 | simplified = gimple_switch_index (stmt); | |
1345 | else | |
1346 | /* These cannot satisfy is_gimple_min_invariant without folding. */ | |
1347 | gcc_assert (code == GIMPLE_CALL || code == GIMPLE_COND); | |
1348 | } | |
6de9cd9a | 1349 | |
6ac01510 ILT |
1350 | is_constant = simplified && is_gimple_min_invariant (simplified); |
1351 | ||
1352 | fold_undefer_overflow_warnings (is_constant, stmt, 0); | |
1353 | ||
00d382a8 RG |
1354 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1355 | { | |
1356 | fprintf (dump_file, "which is likely "); | |
1357 | switch (likelyvalue) | |
1358 | { | |
1359 | case CONSTANT: | |
1360 | fprintf (dump_file, "CONSTANT"); | |
1361 | break; | |
1362 | case UNDEFINED: | |
1363 | fprintf (dump_file, "UNDEFINED"); | |
1364 | break; | |
1365 | case VARYING: | |
1366 | fprintf (dump_file, "VARYING"); | |
1367 | break; | |
1368 | default:; | |
1369 | } | |
1370 | fprintf (dump_file, "\n"); | |
1371 | } | |
1372 | ||
6ac01510 | 1373 | if (is_constant) |
6de9cd9a DN |
1374 | { |
1375 | /* The statement produced a constant value. */ | |
1376 | val.lattice_val = CONSTANT; | |
0bca51f0 | 1377 | val.value = simplified; |
6de9cd9a DN |
1378 | } |
1379 | else | |
1380 | { | |
1381 | /* The statement produced a nonconstant value. If the statement | |
0bca51f0 DN |
1382 | had UNDEFINED operands, then the result of the statement |
1383 | should be UNDEFINED. Otherwise, the statement is VARYING. */ | |
106dec71 | 1384 | if (likelyvalue == UNDEFINED) |
a318e3ac SB |
1385 | val.lattice_val = likelyvalue; |
1386 | else | |
1387 | val.lattice_val = VARYING; | |
1388 | ||
0bca51f0 | 1389 | val.value = NULL_TREE; |
6de9cd9a | 1390 | } |
750628d8 DN |
1391 | |
1392 | return val; | |
6de9cd9a DN |
1393 | } |
1394 | ||
750628d8 | 1395 | /* Visit the assignment statement STMT. Set the value of its LHS to the |
0bca51f0 DN |
1396 | value computed by the RHS and store LHS in *OUTPUT_P. If STMT |
1397 | creates virtual definitions, set the value of each new name to that | |
726a989a RB |
1398 | of the RHS (if we can derive a constant out of the RHS). |
1399 | Value-returning call statements also perform an assignment, and | |
1400 | are handled here. */ | |
6de9cd9a | 1401 | |
750628d8 | 1402 | static enum ssa_prop_result |
726a989a | 1403 | visit_assignment (gimple stmt, tree *output_p) |
6de9cd9a | 1404 | { |
0bca51f0 | 1405 | prop_value_t val; |
0bca51f0 | 1406 | enum ssa_prop_result retval; |
6de9cd9a | 1407 | |
726a989a | 1408 | tree lhs = gimple_get_lhs (stmt); |
6de9cd9a | 1409 | |
726a989a RB |
1410 | gcc_assert (gimple_code (stmt) != GIMPLE_CALL |
1411 | || gimple_call_lhs (stmt) != NULL_TREE); | |
1412 | ||
1413 | if (gimple_assign_copy_p (stmt)) | |
750628d8 | 1414 | { |
726a989a | 1415 | tree rhs = gimple_assign_rhs1 (stmt); |
0bca51f0 | 1416 | |
726a989a RB |
1417 | if (TREE_CODE (rhs) == SSA_NAME) |
1418 | { | |
1419 | /* For a simple copy operation, we copy the lattice values. */ | |
1420 | prop_value_t *nval = get_value (rhs); | |
1421 | val = *nval; | |
1422 | } | |
0bca51f0 | 1423 | else |
726a989a | 1424 | val = evaluate_stmt (stmt); |
750628d8 DN |
1425 | } |
1426 | else | |
726a989a RB |
1427 | /* Evaluate the statement, which could be |
1428 | either a GIMPLE_ASSIGN or a GIMPLE_CALL. */ | |
87e1e42b | 1429 | val = evaluate_stmt (stmt); |
6de9cd9a | 1430 | |
0bca51f0 | 1431 | retval = SSA_PROP_NOT_INTERESTING; |
6de9cd9a | 1432 | |
750628d8 | 1433 | /* Set the lattice value of the statement's output. */ |
0bca51f0 | 1434 | if (TREE_CODE (lhs) == SSA_NAME) |
6de9cd9a | 1435 | { |
0bca51f0 DN |
1436 | /* If STMT is an assignment to an SSA_NAME, we only have one |
1437 | value to set. */ | |
1438 | if (set_lattice_value (lhs, val)) | |
1439 | { | |
1440 | *output_p = lhs; | |
1441 | if (val.lattice_val == VARYING) | |
1442 | retval = SSA_PROP_VARYING; | |
1443 | else | |
1444 | retval = SSA_PROP_INTERESTING; | |
1445 | } | |
6de9cd9a | 1446 | } |
0bca51f0 DN |
1447 | |
1448 | return retval; | |
6de9cd9a DN |
1449 | } |
1450 | ||
6de9cd9a | 1451 | |
750628d8 DN |
1452 | /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING |
1453 | if it can determine which edge will be taken. Otherwise, return | |
1454 | SSA_PROP_VARYING. */ | |
1455 | ||
1456 | static enum ssa_prop_result | |
726a989a | 1457 | visit_cond_stmt (gimple stmt, edge *taken_edge_p) |
6de9cd9a | 1458 | { |
0bca51f0 | 1459 | prop_value_t val; |
750628d8 DN |
1460 | basic_block block; |
1461 | ||
726a989a | 1462 | block = gimple_bb (stmt); |
750628d8 DN |
1463 | val = evaluate_stmt (stmt); |
1464 | ||
1465 | /* Find which edge out of the conditional block will be taken and add it | |
1466 | to the worklist. If no single edge can be determined statically, | |
1467 | return SSA_PROP_VARYING to feed all the outgoing edges to the | |
1468 | propagation engine. */ | |
0bca51f0 | 1469 | *taken_edge_p = val.value ? find_taken_edge (block, val.value) : 0; |
750628d8 DN |
1470 | if (*taken_edge_p) |
1471 | return SSA_PROP_INTERESTING; | |
1472 | else | |
1473 | return SSA_PROP_VARYING; | |
6de9cd9a DN |
1474 | } |
1475 | ||
6de9cd9a | 1476 | |
750628d8 DN |
1477 | /* Evaluate statement STMT. If the statement produces an output value and |
1478 | its evaluation changes the lattice value of its output, return | |
1479 | SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the | |
1480 | output value. | |
1481 | ||
1482 | If STMT is a conditional branch and we can determine its truth | |
1483 | value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying | |
1484 | value, return SSA_PROP_VARYING. */ | |
6de9cd9a | 1485 | |
750628d8 | 1486 | static enum ssa_prop_result |
726a989a | 1487 | ccp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p) |
750628d8 | 1488 | { |
750628d8 DN |
1489 | tree def; |
1490 | ssa_op_iter iter; | |
6de9cd9a | 1491 | |
750628d8 | 1492 | if (dump_file && (dump_flags & TDF_DETAILS)) |
6de9cd9a | 1493 | { |
0bca51f0 | 1494 | fprintf (dump_file, "\nVisiting statement:\n"); |
726a989a | 1495 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
6de9cd9a | 1496 | } |
6de9cd9a | 1497 | |
726a989a | 1498 | switch (gimple_code (stmt)) |
6de9cd9a | 1499 | { |
726a989a RB |
1500 | case GIMPLE_ASSIGN: |
1501 | /* If the statement is an assignment that produces a single | |
1502 | output value, evaluate its RHS to see if the lattice value of | |
1503 | its output has changed. */ | |
1504 | return visit_assignment (stmt, output_p); | |
1505 | ||
1506 | case GIMPLE_CALL: | |
1507 | /* A value-returning call also performs an assignment. */ | |
1508 | if (gimple_call_lhs (stmt) != NULL_TREE) | |
1509 | return visit_assignment (stmt, output_p); | |
1510 | break; | |
1511 | ||
1512 | case GIMPLE_COND: | |
1513 | case GIMPLE_SWITCH: | |
1514 | /* If STMT is a conditional branch, see if we can determine | |
1515 | which branch will be taken. */ | |
1516 | /* FIXME. It appears that we should be able to optimize | |
1517 | computed GOTOs here as well. */ | |
1518 | return visit_cond_stmt (stmt, taken_edge_p); | |
1519 | ||
1520 | default: | |
1521 | break; | |
6de9cd9a | 1522 | } |
6de9cd9a | 1523 | |
750628d8 DN |
1524 | /* Any other kind of statement is not interesting for constant |
1525 | propagation and, therefore, not worth simulating. */ | |
750628d8 DN |
1526 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1527 | fprintf (dump_file, "No interesting values produced. Marked VARYING.\n"); | |
6de9cd9a | 1528 | |
750628d8 DN |
1529 | /* Definitions made by statements other than assignments to |
1530 | SSA_NAMEs represent unknown modifications to their outputs. | |
1531 | Mark them VARYING. */ | |
0bca51f0 DN |
1532 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) |
1533 | { | |
dce2b2f6 | 1534 | prop_value_t v = { VARYING, NULL_TREE }; |
0bca51f0 DN |
1535 | set_lattice_value (def, v); |
1536 | } | |
6de9cd9a | 1537 | |
750628d8 DN |
1538 | return SSA_PROP_VARYING; |
1539 | } | |
6de9cd9a | 1540 | |
6de9cd9a | 1541 | |
0bca51f0 | 1542 | /* Main entry point for SSA Conditional Constant Propagation. */ |
750628d8 | 1543 | |
3253eafb | 1544 | static unsigned int |
dce2b2f6 | 1545 | do_ssa_ccp (void) |
750628d8 DN |
1546 | { |
1547 | ccp_initialize (); | |
1548 | ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node); | |
3253eafb | 1549 | if (ccp_finalize ()) |
706ca88e | 1550 | return (TODO_cleanup_cfg | TODO_update_ssa | TODO_remove_unused_locals); |
3253eafb JH |
1551 | else |
1552 | return 0; | |
6de9cd9a DN |
1553 | } |
1554 | ||
173b818d BB |
1555 | |
1556 | static bool | |
750628d8 | 1557 | gate_ccp (void) |
173b818d | 1558 | { |
750628d8 | 1559 | return flag_tree_ccp != 0; |
173b818d BB |
1560 | } |
1561 | ||
6de9cd9a | 1562 | |
8ddbbcae | 1563 | struct gimple_opt_pass pass_ccp = |
750628d8 | 1564 | { |
8ddbbcae JH |
1565 | { |
1566 | GIMPLE_PASS, | |
750628d8 DN |
1567 | "ccp", /* name */ |
1568 | gate_ccp, /* gate */ | |
0bca51f0 | 1569 | do_ssa_ccp, /* execute */ |
750628d8 DN |
1570 | NULL, /* sub */ |
1571 | NULL, /* next */ | |
1572 | 0, /* static_pass_number */ | |
1573 | TV_TREE_CCP, /* tv_id */ | |
7faade0f | 1574 | PROP_cfg | PROP_ssa, /* properties_required */ |
750628d8 | 1575 | 0, /* properties_provided */ |
ae07b463 | 1576 | 0, /* properties_destroyed */ |
750628d8 | 1577 | 0, /* todo_flags_start */ |
3253eafb | 1578 | TODO_dump_func | TODO_verify_ssa |
8ddbbcae JH |
1579 | | TODO_verify_stmts | TODO_ggc_collect/* todo_flags_finish */ |
1580 | } | |
750628d8 | 1581 | }; |
6de9cd9a | 1582 | |
6de9cd9a | 1583 | |
6de9cd9a DN |
1584 | /* A subroutine of fold_stmt_r. Attempts to fold *(A+O) to A[X]. |
1585 | BASE is an array type. OFFSET is a byte displacement. ORIG_TYPE | |
9cf737f8 | 1586 | is the desired result type. */ |
6de9cd9a DN |
1587 | |
1588 | static tree | |
1fd89060 RG |
1589 | maybe_fold_offset_to_array_ref (tree base, tree offset, tree orig_type, |
1590 | bool allow_negative_idx) | |
6de9cd9a | 1591 | { |
891fc5e9 | 1592 | tree min_idx, idx, idx_type, elt_offset = integer_zero_node; |
44de5aeb | 1593 | tree array_type, elt_type, elt_size; |
3097760b | 1594 | tree domain_type; |
44de5aeb RK |
1595 | |
1596 | /* If BASE is an ARRAY_REF, we can pick up another offset (this time | |
1597 | measured in units of the size of elements type) from that ARRAY_REF). | |
1598 | We can't do anything if either is variable. | |
1599 | ||
1600 | The case we handle here is *(&A[N]+O). */ | |
1601 | if (TREE_CODE (base) == ARRAY_REF) | |
1602 | { | |
1603 | tree low_bound = array_ref_low_bound (base); | |
1604 | ||
1605 | elt_offset = TREE_OPERAND (base, 1); | |
1606 | if (TREE_CODE (low_bound) != INTEGER_CST | |
1607 | || TREE_CODE (elt_offset) != INTEGER_CST) | |
1608 | return NULL_TREE; | |
1609 | ||
1610 | elt_offset = int_const_binop (MINUS_EXPR, elt_offset, low_bound, 0); | |
1611 | base = TREE_OPERAND (base, 0); | |
1612 | } | |
6de9cd9a DN |
1613 | |
1614 | /* Ignore stupid user tricks of indexing non-array variables. */ | |
1615 | array_type = TREE_TYPE (base); | |
1616 | if (TREE_CODE (array_type) != ARRAY_TYPE) | |
1617 | return NULL_TREE; | |
1618 | elt_type = TREE_TYPE (array_type); | |
f4088621 | 1619 | if (!useless_type_conversion_p (orig_type, elt_type)) |
6de9cd9a | 1620 | return NULL_TREE; |
891fc5e9 RG |
1621 | |
1622 | /* Use signed size type for intermediate computation on the index. */ | |
1623 | idx_type = signed_type_for (size_type_node); | |
1624 | ||
44de5aeb RK |
1625 | /* If OFFSET and ELT_OFFSET are zero, we don't care about the size of the |
1626 | element type (so we can use the alignment if it's not constant). | |
1627 | Otherwise, compute the offset as an index by using a division. If the | |
1628 | division isn't exact, then don't do anything. */ | |
6de9cd9a | 1629 | elt_size = TYPE_SIZE_UNIT (elt_type); |
fe9821b8 JH |
1630 | if (!elt_size) |
1631 | return NULL; | |
44de5aeb RK |
1632 | if (integer_zerop (offset)) |
1633 | { | |
1634 | if (TREE_CODE (elt_size) != INTEGER_CST) | |
1635 | elt_size = size_int (TYPE_ALIGN (elt_type)); | |
6de9cd9a | 1636 | |
891fc5e9 | 1637 | idx = build_int_cst (idx_type, 0); |
44de5aeb RK |
1638 | } |
1639 | else | |
1640 | { | |
1641 | unsigned HOST_WIDE_INT lquo, lrem; | |
1642 | HOST_WIDE_INT hquo, hrem; | |
891fc5e9 | 1643 | double_int soffset; |
44de5aeb | 1644 | |
891fc5e9 RG |
1645 | /* The final array offset should be signed, so we need |
1646 | to sign-extend the (possibly pointer) offset here | |
1647 | and use signed division. */ | |
1648 | soffset = double_int_sext (tree_to_double_int (offset), | |
1649 | TYPE_PRECISION (TREE_TYPE (offset))); | |
44de5aeb | 1650 | if (TREE_CODE (elt_size) != INTEGER_CST |
891fc5e9 RG |
1651 | || div_and_round_double (TRUNC_DIV_EXPR, 0, |
1652 | soffset.low, soffset.high, | |
44de5aeb RK |
1653 | TREE_INT_CST_LOW (elt_size), |
1654 | TREE_INT_CST_HIGH (elt_size), | |
1655 | &lquo, &hquo, &lrem, &hrem) | |
1656 | || lrem || hrem) | |
1657 | return NULL_TREE; | |
6de9cd9a | 1658 | |
891fc5e9 | 1659 | idx = build_int_cst_wide (idx_type, lquo, hquo); |
44de5aeb RK |
1660 | } |
1661 | ||
1662 | /* Assume the low bound is zero. If there is a domain type, get the | |
1663 | low bound, if any, convert the index into that type, and add the | |
1664 | low bound. */ | |
891fc5e9 | 1665 | min_idx = build_int_cst (idx_type, 0); |
3097760b JH |
1666 | domain_type = TYPE_DOMAIN (array_type); |
1667 | if (domain_type) | |
6de9cd9a | 1668 | { |
3097760b | 1669 | idx_type = domain_type; |
891fc5e9 RG |
1670 | if (TYPE_MIN_VALUE (idx_type)) |
1671 | min_idx = TYPE_MIN_VALUE (idx_type); | |
44de5aeb | 1672 | else |
891fc5e9 | 1673 | min_idx = fold_convert (idx_type, min_idx); |
44de5aeb RK |
1674 | |
1675 | if (TREE_CODE (min_idx) != INTEGER_CST) | |
1676 | return NULL_TREE; | |
1677 | ||
891fc5e9 | 1678 | elt_offset = fold_convert (idx_type, elt_offset); |
6de9cd9a DN |
1679 | } |
1680 | ||
44de5aeb RK |
1681 | if (!integer_zerop (min_idx)) |
1682 | idx = int_const_binop (PLUS_EXPR, idx, min_idx, 0); | |
1683 | if (!integer_zerop (elt_offset)) | |
1684 | idx = int_const_binop (PLUS_EXPR, idx, elt_offset, 0); | |
1685 | ||
891fc5e9 RG |
1686 | /* Make sure to possibly truncate late after offsetting. */ |
1687 | idx = fold_convert (idx_type, idx); | |
1688 | ||
3097760b | 1689 | /* We don't want to construct access past array bounds. For example |
1fd89060 RG |
1690 | char *(c[4]); |
1691 | c[3][2]; | |
1692 | should not be simplified into (*c)[14] or tree-vrp will | |
1693 | give false warnings. The same is true for | |
1694 | struct A { long x; char d[0]; } *a; | |
1695 | (char *)a - 4; | |
1696 | which should be not folded to &a->d[-8]. */ | |
1697 | if (domain_type | |
1698 | && TYPE_MAX_VALUE (domain_type) | |
3097760b JH |
1699 | && TREE_CODE (TYPE_MAX_VALUE (domain_type)) == INTEGER_CST) |
1700 | { | |
1701 | tree up_bound = TYPE_MAX_VALUE (domain_type); | |
1702 | ||
1703 | if (tree_int_cst_lt (up_bound, idx) | |
1704 | /* Accesses after the end of arrays of size 0 (gcc | |
1705 | extension) and 1 are likely intentional ("struct | |
1706 | hack"). */ | |
1707 | && compare_tree_int (up_bound, 1) > 0) | |
1708 | return NULL_TREE; | |
1709 | } | |
1fd89060 RG |
1710 | if (domain_type |
1711 | && TYPE_MIN_VALUE (domain_type)) | |
1712 | { | |
1713 | if (!allow_negative_idx | |
1714 | && TREE_CODE (TYPE_MIN_VALUE (domain_type)) == INTEGER_CST | |
1715 | && tree_int_cst_lt (idx, TYPE_MIN_VALUE (domain_type))) | |
1716 | return NULL_TREE; | |
1717 | } | |
1718 | else if (!allow_negative_idx | |
1719 | && compare_tree_int (idx, 0) < 0) | |
1720 | return NULL_TREE; | |
3097760b | 1721 | |
04d86531 | 1722 | return build4 (ARRAY_REF, elt_type, base, idx, NULL_TREE, NULL_TREE); |
6de9cd9a DN |
1723 | } |
1724 | ||
750628d8 | 1725 | |
fe9821b8 | 1726 | /* Attempt to fold *(S+O) to S.X. |
6de9cd9a DN |
1727 | BASE is a record type. OFFSET is a byte displacement. ORIG_TYPE |
1728 | is the desired result type. */ | |
6de9cd9a | 1729 | |
fe9821b8 | 1730 | static tree |
6de9cd9a DN |
1731 | maybe_fold_offset_to_component_ref (tree record_type, tree base, tree offset, |
1732 | tree orig_type, bool base_is_ptr) | |
1733 | { | |
f34fa464 | 1734 | tree f, t, field_type, tail_array_field, field_offset; |
6e6e19cb JH |
1735 | tree ret; |
1736 | tree new_base; | |
6de9cd9a DN |
1737 | |
1738 | if (TREE_CODE (record_type) != RECORD_TYPE | |
1739 | && TREE_CODE (record_type) != UNION_TYPE | |
1740 | && TREE_CODE (record_type) != QUAL_UNION_TYPE) | |
1741 | return NULL_TREE; | |
1742 | ||
1743 | /* Short-circuit silly cases. */ | |
f4088621 | 1744 | if (useless_type_conversion_p (record_type, orig_type)) |
6de9cd9a DN |
1745 | return NULL_TREE; |
1746 | ||
1747 | tail_array_field = NULL_TREE; | |
1748 | for (f = TYPE_FIELDS (record_type); f ; f = TREE_CHAIN (f)) | |
1749 | { | |
1750 | int cmp; | |
1751 | ||
1752 | if (TREE_CODE (f) != FIELD_DECL) | |
1753 | continue; | |
1754 | if (DECL_BIT_FIELD (f)) | |
1755 | continue; | |
f34fa464 | 1756 | |
fe9821b8 JH |
1757 | if (!DECL_FIELD_OFFSET (f)) |
1758 | continue; | |
f34fa464 ZD |
1759 | field_offset = byte_position (f); |
1760 | if (TREE_CODE (field_offset) != INTEGER_CST) | |
6de9cd9a DN |
1761 | continue; |
1762 | ||
1763 | /* ??? Java creates "interesting" fields for representing base classes. | |
1764 | They have no name, and have no context. With no context, we get into | |
1765 | trouble with nonoverlapping_component_refs_p. Skip them. */ | |
1766 | if (!DECL_FIELD_CONTEXT (f)) | |
1767 | continue; | |
1768 | ||
1769 | /* The previous array field isn't at the end. */ | |
1770 | tail_array_field = NULL_TREE; | |
1771 | ||
1772 | /* Check to see if this offset overlaps with the field. */ | |
f34fa464 | 1773 | cmp = tree_int_cst_compare (field_offset, offset); |
6de9cd9a DN |
1774 | if (cmp > 0) |
1775 | continue; | |
1776 | ||
1777 | field_type = TREE_TYPE (f); | |
6de9cd9a DN |
1778 | |
1779 | /* Here we exactly match the offset being checked. If the types match, | |
1780 | then we can return that field. */ | |
53dba802 | 1781 | if (cmp == 0 |
f4088621 | 1782 | && useless_type_conversion_p (orig_type, field_type)) |
6de9cd9a DN |
1783 | { |
1784 | if (base_is_ptr) | |
1785 | base = build1 (INDIRECT_REF, record_type, base); | |
b4257cfc | 1786 | t = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE); |
6de9cd9a DN |
1787 | return t; |
1788 | } | |
53dba802 ZD |
1789 | |
1790 | /* Don't care about offsets into the middle of scalars. */ | |
1791 | if (!AGGREGATE_TYPE_P (field_type)) | |
1792 | continue; | |
6de9cd9a | 1793 | |
53dba802 ZD |
1794 | /* Check for array at the end of the struct. This is often |
1795 | used as for flexible array members. We should be able to | |
1796 | turn this into an array access anyway. */ | |
1797 | if (TREE_CODE (field_type) == ARRAY_TYPE) | |
1798 | tail_array_field = f; | |
1799 | ||
1800 | /* Check the end of the field against the offset. */ | |
1801 | if (!DECL_SIZE_UNIT (f) | |
1802 | || TREE_CODE (DECL_SIZE_UNIT (f)) != INTEGER_CST) | |
1803 | continue; | |
1804 | t = int_const_binop (MINUS_EXPR, offset, field_offset, 1); | |
1805 | if (!tree_int_cst_lt (t, DECL_SIZE_UNIT (f))) | |
1806 | continue; | |
6de9cd9a | 1807 | |
53dba802 ZD |
1808 | /* If we matched, then set offset to the displacement into |
1809 | this field. */ | |
6e6e19cb JH |
1810 | if (base_is_ptr) |
1811 | new_base = build1 (INDIRECT_REF, record_type, base); | |
1812 | else | |
1813 | new_base = base; | |
1814 | new_base = build3 (COMPONENT_REF, field_type, new_base, f, NULL_TREE); | |
1815 | ||
1816 | /* Recurse to possibly find the match. */ | |
1fd89060 RG |
1817 | ret = maybe_fold_offset_to_array_ref (new_base, t, orig_type, |
1818 | f == TYPE_FIELDS (record_type)); | |
6e6e19cb JH |
1819 | if (ret) |
1820 | return ret; | |
1821 | ret = maybe_fold_offset_to_component_ref (field_type, new_base, t, | |
1822 | orig_type, false); | |
1823 | if (ret) | |
1824 | return ret; | |
6de9cd9a DN |
1825 | } |
1826 | ||
1827 | if (!tail_array_field) | |
1828 | return NULL_TREE; | |
1829 | ||
1830 | f = tail_array_field; | |
1831 | field_type = TREE_TYPE (f); | |
53dba802 | 1832 | offset = int_const_binop (MINUS_EXPR, offset, byte_position (f), 1); |
6de9cd9a | 1833 | |
6de9cd9a | 1834 | /* If we get here, we've got an aggregate field, and a possibly |
1ea7e6ad | 1835 | nonzero offset into them. Recurse and hope for a valid match. */ |
6de9cd9a DN |
1836 | if (base_is_ptr) |
1837 | base = build1 (INDIRECT_REF, record_type, base); | |
b4257cfc | 1838 | base = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE); |
6de9cd9a | 1839 | |
1fd89060 RG |
1840 | t = maybe_fold_offset_to_array_ref (base, offset, orig_type, |
1841 | f == TYPE_FIELDS (record_type)); | |
6de9cd9a DN |
1842 | if (t) |
1843 | return t; | |
1844 | return maybe_fold_offset_to_component_ref (field_type, base, offset, | |
1845 | orig_type, false); | |
1846 | } | |
1847 | ||
fe9821b8 JH |
1848 | /* Attempt to express (ORIG_TYPE)BASE+OFFSET as BASE->field_of_orig_type |
1849 | or BASE[index] or by combination of those. | |
1850 | ||
1851 | Before attempting the conversion strip off existing ADDR_EXPRs and | |
1852 | handled component refs. */ | |
1853 | ||
1854 | tree | |
1855 | maybe_fold_offset_to_reference (tree base, tree offset, tree orig_type) | |
1856 | { | |
1857 | tree ret; | |
1858 | tree type; | |
1859 | bool base_is_ptr = true; | |
1860 | ||
1861 | STRIP_NOPS (base); | |
1862 | if (TREE_CODE (base) == ADDR_EXPR) | |
1863 | { | |
1864 | base_is_ptr = false; | |
1865 | ||
1866 | base = TREE_OPERAND (base, 0); | |
1867 | ||
1868 | /* Handle case where existing COMPONENT_REF pick e.g. wrong field of union, | |
1869 | so it needs to be removed and new COMPONENT_REF constructed. | |
1870 | The wrong COMPONENT_REF are often constructed by folding the | |
1871 | (type *)&object within the expression (type *)&object+offset */ | |
99f536cc | 1872 | if (handled_component_p (base)) |
fe9821b8 JH |
1873 | { |
1874 | HOST_WIDE_INT sub_offset, size, maxsize; | |
1875 | tree newbase; | |
1876 | newbase = get_ref_base_and_extent (base, &sub_offset, | |
1877 | &size, &maxsize); | |
1878 | gcc_assert (newbase); | |
99f536cc | 1879 | if (size == maxsize |
a214f4d6 | 1880 | && size != -1 |
99f536cc | 1881 | && !(sub_offset & (BITS_PER_UNIT - 1))) |
fe9821b8 JH |
1882 | { |
1883 | base = newbase; | |
1884 | if (sub_offset) | |
1885 | offset = int_const_binop (PLUS_EXPR, offset, | |
1886 | build_int_cst (TREE_TYPE (offset), | |
1887 | sub_offset / BITS_PER_UNIT), 1); | |
1888 | } | |
1889 | } | |
f4088621 | 1890 | if (useless_type_conversion_p (orig_type, TREE_TYPE (base)) |
fe9821b8 JH |
1891 | && integer_zerop (offset)) |
1892 | return base; | |
1893 | type = TREE_TYPE (base); | |
1894 | } | |
1895 | else | |
1896 | { | |
1897 | base_is_ptr = true; | |
1898 | if (!POINTER_TYPE_P (TREE_TYPE (base))) | |
1899 | return NULL_TREE; | |
1900 | type = TREE_TYPE (TREE_TYPE (base)); | |
1901 | } | |
1902 | ret = maybe_fold_offset_to_component_ref (type, base, offset, | |
1903 | orig_type, base_is_ptr); | |
1904 | if (!ret) | |
1905 | { | |
1906 | if (base_is_ptr) | |
1907 | base = build1 (INDIRECT_REF, type, base); | |
1fd89060 | 1908 | ret = maybe_fold_offset_to_array_ref (base, offset, orig_type, true); |
fe9821b8 JH |
1909 | } |
1910 | return ret; | |
1911 | } | |
750628d8 | 1912 | |
99f536cc RG |
1913 | /* Attempt to express (ORIG_TYPE)&BASE+OFFSET as &BASE->field_of_orig_type |
1914 | or &BASE[index] or by combination of those. | |
1915 | ||
1916 | Before attempting the conversion strip off existing component refs. */ | |
1917 | ||
1918 | tree | |
1919 | maybe_fold_offset_to_address (tree addr, tree offset, tree orig_type) | |
1920 | { | |
1921 | tree t; | |
1922 | ||
1923 | gcc_assert (POINTER_TYPE_P (TREE_TYPE (addr)) | |
1924 | && POINTER_TYPE_P (orig_type)); | |
1925 | ||
1926 | t = maybe_fold_offset_to_reference (addr, offset, TREE_TYPE (orig_type)); | |
1927 | if (t != NULL_TREE) | |
1928 | { | |
1929 | tree orig = addr; | |
1930 | tree ptr_type; | |
1931 | ||
1932 | /* For __builtin_object_size to function correctly we need to | |
1933 | make sure not to fold address arithmetic so that we change | |
1934 | reference from one array to another. This would happen for | |
1935 | example for | |
1936 | ||
1937 | struct X { char s1[10]; char s2[10] } s; | |
1938 | char *foo (void) { return &s.s2[-4]; } | |
1939 | ||
1940 | where we need to avoid generating &s.s1[6]. As the C and | |
1941 | C++ frontends create different initial trees | |
1942 | (char *) &s.s1 + -4 vs. &s.s1[-4] we have to do some | |
1943 | sophisticated comparisons here. Note that checking for the | |
1944 | condition after the fact is easier than trying to avoid doing | |
1945 | the folding. */ | |
1946 | STRIP_NOPS (orig); | |
1947 | if (TREE_CODE (orig) == ADDR_EXPR) | |
1948 | orig = TREE_OPERAND (orig, 0); | |
1949 | if ((TREE_CODE (orig) == ARRAY_REF | |
1950 | || (TREE_CODE (orig) == COMPONENT_REF | |
1951 | && TREE_CODE (TREE_TYPE (TREE_OPERAND (orig, 1))) == ARRAY_TYPE)) | |
1952 | && (TREE_CODE (t) == ARRAY_REF | |
1953 | || (TREE_CODE (t) == COMPONENT_REF | |
1954 | && TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 1))) == ARRAY_TYPE)) | |
1955 | && !operand_equal_p (TREE_CODE (orig) == ARRAY_REF | |
1956 | ? TREE_OPERAND (orig, 0) : orig, | |
1957 | TREE_CODE (t) == ARRAY_REF | |
1958 | ? TREE_OPERAND (t, 0) : t, 0)) | |
1959 | return NULL_TREE; | |
1960 | ||
1961 | ptr_type = build_pointer_type (TREE_TYPE (t)); | |
1962 | if (!useless_type_conversion_p (orig_type, ptr_type)) | |
1963 | return NULL_TREE; | |
1964 | return build_fold_addr_expr_with_type (t, ptr_type); | |
1965 | } | |
1966 | ||
1967 | return NULL_TREE; | |
1968 | } | |
1969 | ||
6de9cd9a DN |
1970 | /* A subroutine of fold_stmt_r. Attempt to simplify *(BASE+OFFSET). |
1971 | Return the simplified expression, or NULL if nothing could be done. */ | |
1972 | ||
1973 | static tree | |
1974 | maybe_fold_stmt_indirect (tree expr, tree base, tree offset) | |
1975 | { | |
1976 | tree t; | |
cbf8d355 | 1977 | bool volatile_p = TREE_THIS_VOLATILE (expr); |
6de9cd9a DN |
1978 | |
1979 | /* We may well have constructed a double-nested PLUS_EXPR via multiple | |
1980 | substitutions. Fold that down to one. Remove NON_LVALUE_EXPRs that | |
1981 | are sometimes added. */ | |
1982 | base = fold (base); | |
ff7c8597 | 1983 | STRIP_TYPE_NOPS (base); |
6de9cd9a DN |
1984 | TREE_OPERAND (expr, 0) = base; |
1985 | ||
1986 | /* One possibility is that the address reduces to a string constant. */ | |
1987 | t = fold_read_from_constant_string (expr); | |
1988 | if (t) | |
1989 | return t; | |
1990 | ||
5be014d5 AP |
1991 | /* Add in any offset from a POINTER_PLUS_EXPR. */ |
1992 | if (TREE_CODE (base) == POINTER_PLUS_EXPR) | |
6de9cd9a DN |
1993 | { |
1994 | tree offset2; | |
1995 | ||
1996 | offset2 = TREE_OPERAND (base, 1); | |
1997 | if (TREE_CODE (offset2) != INTEGER_CST) | |
1998 | return NULL_TREE; | |
1999 | base = TREE_OPERAND (base, 0); | |
2000 | ||
5be014d5 AP |
2001 | offset = fold_convert (sizetype, |
2002 | int_const_binop (PLUS_EXPR, offset, offset2, 1)); | |
6de9cd9a DN |
2003 | } |
2004 | ||
2005 | if (TREE_CODE (base) == ADDR_EXPR) | |
2006 | { | |
fe9821b8 JH |
2007 | tree base_addr = base; |
2008 | ||
6de9cd9a DN |
2009 | /* Strip the ADDR_EXPR. */ |
2010 | base = TREE_OPERAND (base, 0); | |
2011 | ||
0534fa56 RH |
2012 | /* Fold away CONST_DECL to its value, if the type is scalar. */ |
2013 | if (TREE_CODE (base) == CONST_DECL | |
1b738915 | 2014 | && is_gimple_min_invariant (DECL_INITIAL (base))) |
0534fa56 RH |
2015 | return DECL_INITIAL (base); |
2016 | ||
6de9cd9a | 2017 | /* Try folding *(&B+O) to B.X. */ |
fe9821b8 JH |
2018 | t = maybe_fold_offset_to_reference (base_addr, offset, |
2019 | TREE_TYPE (expr)); | |
6de9cd9a | 2020 | if (t) |
cbf8d355 | 2021 | { |
e2104f59 RG |
2022 | /* Preserve volatileness of the original expression. |
2023 | We can end up with a plain decl here which is shared | |
2024 | and we shouldn't mess with its flags. */ | |
2025 | if (!SSA_VAR_P (t)) | |
2026 | TREE_THIS_VOLATILE (t) = volatile_p; | |
cbf8d355 RG |
2027 | return t; |
2028 | } | |
6de9cd9a DN |
2029 | } |
2030 | else | |
2031 | { | |
2032 | /* We can get here for out-of-range string constant accesses, | |
2033 | such as "_"[3]. Bail out of the entire substitution search | |
2034 | and arrange for the entire statement to be replaced by a | |
aabcd309 | 2035 | call to __builtin_trap. In all likelihood this will all be |
6de9cd9a DN |
2036 | constant-folded away, but in the meantime we can't leave with |
2037 | something that get_expr_operands can't understand. */ | |
2038 | ||
2039 | t = base; | |
2040 | STRIP_NOPS (t); | |
2041 | if (TREE_CODE (t) == ADDR_EXPR | |
2042 | && TREE_CODE (TREE_OPERAND (t, 0)) == STRING_CST) | |
2043 | { | |
2044 | /* FIXME: Except that this causes problems elsewhere with dead | |
0e61db61 | 2045 | code not being deleted, and we die in the rtl expanders |
6de9cd9a DN |
2046 | because we failed to remove some ssa_name. In the meantime, |
2047 | just return zero. */ | |
2048 | /* FIXME2: This condition should be signaled by | |
2049 | fold_read_from_constant_string directly, rather than | |
2050 | re-checking for it here. */ | |
2051 | return integer_zero_node; | |
2052 | } | |
2053 | ||
2054 | /* Try folding *(B+O) to B->X. Still an improvement. */ | |
2055 | if (POINTER_TYPE_P (TREE_TYPE (base))) | |
2056 | { | |
fe9821b8 JH |
2057 | t = maybe_fold_offset_to_reference (base, offset, |
2058 | TREE_TYPE (expr)); | |
6de9cd9a DN |
2059 | if (t) |
2060 | return t; | |
2061 | } | |
2062 | } | |
2063 | ||
2064 | /* Otherwise we had an offset that we could not simplify. */ | |
2065 | return NULL_TREE; | |
2066 | } | |
2067 | ||
750628d8 | 2068 | |
726a989a | 2069 | /* A quaint feature extant in our address arithmetic is that there |
6de9cd9a DN |
2070 | can be hidden type changes here. The type of the result need |
2071 | not be the same as the type of the input pointer. | |
2072 | ||
2073 | What we're after here is an expression of the form | |
2074 | (T *)(&array + const) | |
726a989a RB |
2075 | where array is OP0, const is OP1, RES_TYPE is T and |
2076 | the cast doesn't actually exist, but is implicit in the | |
5be014d5 | 2077 | type of the POINTER_PLUS_EXPR. We'd like to turn this into |
6de9cd9a DN |
2078 | &array[x] |
2079 | which may be able to propagate further. */ | |
2080 | ||
726a989a RB |
2081 | tree |
2082 | maybe_fold_stmt_addition (tree res_type, tree op0, tree op1) | |
6de9cd9a | 2083 | { |
6de9cd9a DN |
2084 | tree ptd_type; |
2085 | tree t; | |
6de9cd9a | 2086 | |
6de9cd9a DN |
2087 | /* It had better be a constant. */ |
2088 | if (TREE_CODE (op1) != INTEGER_CST) | |
2089 | return NULL_TREE; | |
2090 | /* The first operand should be an ADDR_EXPR. */ | |
2091 | if (TREE_CODE (op0) != ADDR_EXPR) | |
2092 | return NULL_TREE; | |
2093 | op0 = TREE_OPERAND (op0, 0); | |
2094 | ||
2095 | /* If the first operand is an ARRAY_REF, expand it so that we can fold | |
2096 | the offset into it. */ | |
2097 | while (TREE_CODE (op0) == ARRAY_REF) | |
2098 | { | |
2099 | tree array_obj = TREE_OPERAND (op0, 0); | |
2100 | tree array_idx = TREE_OPERAND (op0, 1); | |
2101 | tree elt_type = TREE_TYPE (op0); | |
2102 | tree elt_size = TYPE_SIZE_UNIT (elt_type); | |
2103 | tree min_idx; | |
2104 | ||
2105 | if (TREE_CODE (array_idx) != INTEGER_CST) | |
2106 | break; | |
2107 | if (TREE_CODE (elt_size) != INTEGER_CST) | |
2108 | break; | |
2109 | ||
2110 | /* Un-bias the index by the min index of the array type. */ | |
2111 | min_idx = TYPE_DOMAIN (TREE_TYPE (array_obj)); | |
2112 | if (min_idx) | |
2113 | { | |
2114 | min_idx = TYPE_MIN_VALUE (min_idx); | |
2115 | if (min_idx) | |
2116 | { | |
44de5aeb RK |
2117 | if (TREE_CODE (min_idx) != INTEGER_CST) |
2118 | break; | |
2119 | ||
b6f65e3c | 2120 | array_idx = fold_convert (TREE_TYPE (min_idx), array_idx); |
6de9cd9a DN |
2121 | if (!integer_zerop (min_idx)) |
2122 | array_idx = int_const_binop (MINUS_EXPR, array_idx, | |
2123 | min_idx, 0); | |
2124 | } | |
2125 | } | |
2126 | ||
2127 | /* Convert the index to a byte offset. */ | |
b6f65e3c | 2128 | array_idx = fold_convert (sizetype, array_idx); |
6de9cd9a DN |
2129 | array_idx = int_const_binop (MULT_EXPR, array_idx, elt_size, 0); |
2130 | ||
2131 | /* Update the operands for the next round, or for folding. */ | |
5be014d5 | 2132 | op1 = int_const_binop (PLUS_EXPR, |
6de9cd9a | 2133 | array_idx, op1, 0); |
6de9cd9a DN |
2134 | op0 = array_obj; |
2135 | } | |
2136 | ||
726a989a | 2137 | ptd_type = TREE_TYPE (res_type); |
c4e5b5a8 RG |
2138 | /* If we want a pointer to void, reconstruct the reference from the |
2139 | array element type. A pointer to that can be trivially converted | |
2140 | to void *. This happens as we fold (void *)(ptr p+ off). */ | |
2141 | if (VOID_TYPE_P (ptd_type) | |
2142 | && TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE) | |
2143 | ptd_type = TREE_TYPE (TREE_TYPE (op0)); | |
6de9cd9a DN |
2144 | |
2145 | /* At which point we can try some of the same things as for indirects. */ | |
1fd89060 | 2146 | t = maybe_fold_offset_to_array_ref (op0, op1, ptd_type, true); |
6de9cd9a DN |
2147 | if (!t) |
2148 | t = maybe_fold_offset_to_component_ref (TREE_TYPE (op0), op0, op1, | |
2149 | ptd_type, false); | |
2150 | if (t) | |
726a989a | 2151 | t = build1 (ADDR_EXPR, res_type, t); |
6de9cd9a DN |
2152 | |
2153 | return t; | |
2154 | } | |
2155 | ||
622f91ba JL |
2156 | /* For passing state through walk_tree into fold_stmt_r and its |
2157 | children. */ | |
2158 | ||
2159 | struct fold_stmt_r_data | |
2160 | { | |
726a989a | 2161 | gimple stmt; |
6ac01510 ILT |
2162 | bool *changed_p; |
2163 | bool *inside_addr_expr_p; | |
622f91ba JL |
2164 | }; |
2165 | ||
6de9cd9a DN |
2166 | /* Subroutine of fold_stmt called via walk_tree. We perform several |
2167 | simplifications of EXPR_P, mostly having to do with pointer arithmetic. */ | |
2168 | ||
2169 | static tree | |
2170 | fold_stmt_r (tree *expr_p, int *walk_subtrees, void *data) | |
2171 | { | |
726a989a RB |
2172 | struct walk_stmt_info *wi = (struct walk_stmt_info *) data; |
2173 | struct fold_stmt_r_data *fold_stmt_r_data; | |
2174 | bool *inside_addr_expr_p; | |
2175 | bool *changed_p; | |
6de9cd9a | 2176 | tree expr = *expr_p, t; |
6aaa4013 | 2177 | bool volatile_p = TREE_THIS_VOLATILE (expr); |
6de9cd9a | 2178 | |
726a989a RB |
2179 | fold_stmt_r_data = (struct fold_stmt_r_data *) wi->info; |
2180 | inside_addr_expr_p = fold_stmt_r_data->inside_addr_expr_p; | |
2181 | changed_p = fold_stmt_r_data->changed_p; | |
2182 | ||
6de9cd9a DN |
2183 | /* ??? It'd be nice if walk_tree had a pre-order option. */ |
2184 | switch (TREE_CODE (expr)) | |
2185 | { | |
2186 | case INDIRECT_REF: | |
2187 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
2188 | if (t) | |
2189 | return t; | |
2190 | *walk_subtrees = 0; | |
2191 | ||
2192 | t = maybe_fold_stmt_indirect (expr, TREE_OPERAND (expr, 0), | |
2193 | integer_zero_node); | |
bab4e8fb JJ |
2194 | /* Avoid folding *"abc" = 5 into 'a' = 5. */ |
2195 | if (wi->is_lhs && t && TREE_CODE (t) == INTEGER_CST) | |
2196 | t = NULL_TREE; | |
16ac8575 RG |
2197 | if (!t |
2198 | && TREE_CODE (TREE_OPERAND (expr, 0)) == ADDR_EXPR) | |
2199 | /* If we had a good reason for propagating the address here, | |
2200 | make sure we end up with valid gimple. See PR34989. */ | |
2201 | t = TREE_OPERAND (TREE_OPERAND (expr, 0), 0); | |
6de9cd9a DN |
2202 | break; |
2203 | ||
fe9821b8 JH |
2204 | case NOP_EXPR: |
2205 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
2206 | if (t) | |
2207 | return t; | |
2208 | *walk_subtrees = 0; | |
2209 | ||
2210 | if (POINTER_TYPE_P (TREE_TYPE (expr)) | |
129a37fc | 2211 | && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (expr))) |
fe9821b8 | 2212 | && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0))) |
99f536cc RG |
2213 | && (t = maybe_fold_offset_to_address (TREE_OPERAND (expr, 0), |
2214 | integer_zero_node, | |
2215 | TREE_TYPE (TREE_TYPE (expr))))) | |
2216 | return t; | |
fe9821b8 JH |
2217 | break; |
2218 | ||
622f91ba | 2219 | /* ??? Could handle more ARRAY_REFs here, as a variant of INDIRECT_REF. |
6de9cd9a DN |
2220 | We'd only want to bother decomposing an existing ARRAY_REF if |
2221 | the base array is found to have another offset contained within. | |
2222 | Otherwise we'd be wasting time. */ | |
622f91ba JL |
2223 | case ARRAY_REF: |
2224 | /* If we are not processing expressions found within an | |
bab4e8fb JJ |
2225 | ADDR_EXPR, then we can fold constant array references. |
2226 | Don't fold on LHS either, to avoid folding "abc"[0] = 5 | |
2227 | into 'a' = 5. */ | |
2228 | if (!*inside_addr_expr_p && !wi->is_lhs) | |
622f91ba JL |
2229 | t = fold_read_from_constant_string (expr); |
2230 | else | |
2231 | t = NULL; | |
2232 | break; | |
6de9cd9a DN |
2233 | |
2234 | case ADDR_EXPR: | |
622f91ba | 2235 | *inside_addr_expr_p = true; |
6de9cd9a | 2236 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); |
622f91ba | 2237 | *inside_addr_expr_p = false; |
6de9cd9a DN |
2238 | if (t) |
2239 | return t; | |
2240 | *walk_subtrees = 0; | |
2241 | ||
51eed280 PB |
2242 | /* Make sure the value is properly considered constant, and so gets |
2243 | propagated as expected. */ | |
6de9cd9a | 2244 | if (*changed_p) |
127203ac | 2245 | recompute_tree_invariant_for_addr_expr (expr); |
6de9cd9a DN |
2246 | return NULL_TREE; |
2247 | ||
6de9cd9a DN |
2248 | case COMPONENT_REF: |
2249 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
2250 | if (t) | |
2251 | return t; | |
2252 | *walk_subtrees = 0; | |
2253 | ||
fa27426e RH |
2254 | /* Make sure the FIELD_DECL is actually a field in the type on the lhs. |
2255 | We've already checked that the records are compatible, so we should | |
2256 | come up with a set of compatible fields. */ | |
2257 | { | |
2258 | tree expr_record = TREE_TYPE (TREE_OPERAND (expr, 0)); | |
2259 | tree expr_field = TREE_OPERAND (expr, 1); | |
2260 | ||
2261 | if (DECL_FIELD_CONTEXT (expr_field) != TYPE_MAIN_VARIANT (expr_record)) | |
2262 | { | |
2263 | expr_field = find_compatible_field (expr_record, expr_field); | |
2264 | TREE_OPERAND (expr, 1) = expr_field; | |
2265 | } | |
2266 | } | |
6de9cd9a DN |
2267 | break; |
2268 | ||
ac182688 ZD |
2269 | case TARGET_MEM_REF: |
2270 | t = maybe_fold_tmr (expr); | |
2271 | break; | |
2272 | ||
726a989a RB |
2273 | case POINTER_PLUS_EXPR: |
2274 | t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
2275 | if (t) | |
2276 | return t; | |
2277 | t = walk_tree (&TREE_OPERAND (expr, 1), fold_stmt_r, data, NULL); | |
2278 | if (t) | |
2279 | return t; | |
2280 | *walk_subtrees = 0; | |
2281 | ||
2282 | t = maybe_fold_stmt_addition (TREE_TYPE (expr), | |
2283 | TREE_OPERAND (expr, 0), | |
2284 | TREE_OPERAND (expr, 1)); | |
2285 | break; | |
2286 | ||
f393e7f5 RG |
2287 | case COND_EXPR: |
2288 | if (COMPARISON_CLASS_P (TREE_OPERAND (expr, 0))) | |
2289 | { | |
2290 | tree op0 = TREE_OPERAND (expr, 0); | |
6ac01510 ILT |
2291 | tree tem; |
2292 | bool set; | |
2293 | ||
2294 | fold_defer_overflow_warnings (); | |
2295 | tem = fold_binary (TREE_CODE (op0), TREE_TYPE (op0), | |
2296 | TREE_OPERAND (op0, 0), | |
2297 | TREE_OPERAND (op0, 1)); | |
726a989a RB |
2298 | /* This is actually a conditional expression, not a GIMPLE |
2299 | conditional statement, however, the valid_gimple_rhs_p | |
2300 | test still applies. */ | |
2301 | set = tem && is_gimple_condexpr (tem) && valid_gimple_rhs_p (tem); | |
6ac01510 ILT |
2302 | fold_undefer_overflow_warnings (set, fold_stmt_r_data->stmt, 0); |
2303 | if (set) | |
5cdc4a26 | 2304 | { |
726a989a RB |
2305 | COND_EXPR_COND (expr) = tem; |
2306 | t = expr; | |
5cdc4a26 RS |
2307 | break; |
2308 | } | |
f393e7f5 | 2309 | } |
5cdc4a26 | 2310 | return NULL_TREE; |
f393e7f5 | 2311 | |
6de9cd9a DN |
2312 | default: |
2313 | return NULL_TREE; | |
2314 | } | |
2315 | ||
2316 | if (t) | |
2317 | { | |
e2104f59 RG |
2318 | /* Preserve volatileness of the original expression. |
2319 | We can end up with a plain decl here which is shared | |
2320 | and we shouldn't mess with its flags. */ | |
2321 | if (!SSA_VAR_P (t)) | |
2322 | TREE_THIS_VOLATILE (t) = volatile_p; | |
6de9cd9a DN |
2323 | *expr_p = t; |
2324 | *changed_p = true; | |
2325 | } | |
2326 | ||
2327 | return NULL_TREE; | |
2328 | } | |
2329 | ||
10a0d495 JJ |
2330 | /* Return the string length, maximum string length or maximum value of |
2331 | ARG in LENGTH. | |
2332 | If ARG is an SSA name variable, follow its use-def chains. If LENGTH | |
2333 | is not NULL and, for TYPE == 0, its value is not equal to the length | |
2334 | we determine or if we are unable to determine the length or value, | |
2335 | return false. VISITED is a bitmap of visited variables. | |
2336 | TYPE is 0 if string length should be returned, 1 for maximum string | |
2337 | length and 2 for maximum value ARG can have. */ | |
6de9cd9a | 2338 | |
06a9b53f | 2339 | static bool |
10a0d495 | 2340 | get_maxval_strlen (tree arg, tree *length, bitmap visited, int type) |
6de9cd9a | 2341 | { |
726a989a RB |
2342 | tree var, val; |
2343 | gimple def_stmt; | |
750628d8 DN |
2344 | |
2345 | if (TREE_CODE (arg) != SSA_NAME) | |
06a9b53f | 2346 | { |
f255541f RC |
2347 | if (TREE_CODE (arg) == COND_EXPR) |
2348 | return get_maxval_strlen (COND_EXPR_THEN (arg), length, visited, type) | |
2349 | && get_maxval_strlen (COND_EXPR_ELSE (arg), length, visited, type); | |
c4e5b5a8 RG |
2350 | /* We can end up with &(*iftmp_1)[0] here as well, so handle it. */ |
2351 | else if (TREE_CODE (arg) == ADDR_EXPR | |
2352 | && TREE_CODE (TREE_OPERAND (arg, 0)) == ARRAY_REF | |
2353 | && integer_zerop (TREE_OPERAND (TREE_OPERAND (arg, 0), 1))) | |
2354 | { | |
2355 | tree aop0 = TREE_OPERAND (TREE_OPERAND (arg, 0), 0); | |
2356 | if (TREE_CODE (aop0) == INDIRECT_REF | |
2357 | && TREE_CODE (TREE_OPERAND (aop0, 0)) == SSA_NAME) | |
2358 | return get_maxval_strlen (TREE_OPERAND (aop0, 0), | |
2359 | length, visited, type); | |
2360 | } | |
f255541f | 2361 | |
10a0d495 JJ |
2362 | if (type == 2) |
2363 | { | |
2364 | val = arg; | |
2365 | if (TREE_CODE (val) != INTEGER_CST | |
2366 | || tree_int_cst_sgn (val) < 0) | |
2367 | return false; | |
2368 | } | |
2369 | else | |
2370 | val = c_strlen (arg, 1); | |
750628d8 | 2371 | if (!val) |
06a9b53f | 2372 | return false; |
cd709752 | 2373 | |
10a0d495 JJ |
2374 | if (*length) |
2375 | { | |
2376 | if (type > 0) | |
2377 | { | |
2378 | if (TREE_CODE (*length) != INTEGER_CST | |
2379 | || TREE_CODE (val) != INTEGER_CST) | |
2380 | return false; | |
2381 | ||
2382 | if (tree_int_cst_lt (*length, val)) | |
2383 | *length = val; | |
2384 | return true; | |
2385 | } | |
2386 | else if (simple_cst_equal (val, *length) != 1) | |
2387 | return false; | |
2388 | } | |
6de9cd9a | 2389 | |
750628d8 DN |
2390 | *length = val; |
2391 | return true; | |
6de9cd9a | 2392 | } |
06a9b53f | 2393 | |
750628d8 DN |
2394 | /* If we were already here, break the infinite cycle. */ |
2395 | if (bitmap_bit_p (visited, SSA_NAME_VERSION (arg))) | |
2396 | return true; | |
2397 | bitmap_set_bit (visited, SSA_NAME_VERSION (arg)); | |
2398 | ||
2399 | var = arg; | |
2400 | def_stmt = SSA_NAME_DEF_STMT (var); | |
6de9cd9a | 2401 | |
726a989a RB |
2402 | switch (gimple_code (def_stmt)) |
2403 | { | |
2404 | case GIMPLE_ASSIGN: | |
2405 | /* The RHS of the statement defining VAR must either have a | |
2406 | constant length or come from another SSA_NAME with a constant | |
2407 | length. */ | |
2408 | if (gimple_assign_single_p (def_stmt) | |
2409 | || gimple_assign_unary_nop_p (def_stmt)) | |
2410 | { | |
2411 | tree rhs = gimple_assign_rhs1 (def_stmt); | |
2412 | return get_maxval_strlen (rhs, length, visited, type); | |
2413 | } | |
2414 | return false; | |
2415 | ||
2416 | case GIMPLE_PHI: | |
750628d8 DN |
2417 | { |
2418 | /* All the arguments of the PHI node must have the same constant | |
2419 | length. */ | |
726a989a RB |
2420 | unsigned i; |
2421 | ||
2422 | for (i = 0; i < gimple_phi_num_args (def_stmt); i++) | |
2423 | { | |
2424 | tree arg = gimple_phi_arg (def_stmt, i)->def; | |
2425 | ||
2426 | /* If this PHI has itself as an argument, we cannot | |
2427 | determine the string length of this argument. However, | |
2428 | if we can find a constant string length for the other | |
2429 | PHI args then we can still be sure that this is a | |
2430 | constant string length. So be optimistic and just | |
2431 | continue with the next argument. */ | |
2432 | if (arg == gimple_phi_result (def_stmt)) | |
2433 | continue; | |
2434 | ||
2435 | if (!get_maxval_strlen (arg, length, visited, type)) | |
2436 | return false; | |
2437 | } | |
2438 | } | |
2439 | return true; | |
6de9cd9a | 2440 | |
750628d8 | 2441 | default: |
726a989a | 2442 | return false; |
6de9cd9a | 2443 | } |
6de9cd9a DN |
2444 | } |
2445 | ||
2446 | ||
726a989a RB |
2447 | /* Fold builtin call in statement STMT. Returns a simplified tree. |
2448 | We may return a non-constant expression, including another call | |
2449 | to a different function and with different arguments, e.g., | |
2450 | substituting memcpy for strcpy when the string length is known. | |
2451 | Note that some builtins expand into inline code that may not | |
2452 | be valid in GIMPLE. Callers must take care. */ | |
6de9cd9a DN |
2453 | |
2454 | static tree | |
726a989a | 2455 | ccp_fold_builtin (gimple stmt) |
6de9cd9a | 2456 | { |
10a0d495 | 2457 | tree result, val[3]; |
5039610b | 2458 | tree callee, a; |
d9cc481a | 2459 | int arg_idx, type; |
a32e70c3 RS |
2460 | bitmap visited; |
2461 | bool ignore; | |
5039610b | 2462 | int nargs; |
6de9cd9a | 2463 | |
726a989a RB |
2464 | gcc_assert (is_gimple_call (stmt)); |
2465 | ||
2466 | ignore = (gimple_call_lhs (stmt) == NULL); | |
6de9cd9a DN |
2467 | |
2468 | /* First try the generic builtin folder. If that succeeds, return the | |
2469 | result directly. */ | |
726a989a | 2470 | result = fold_call_stmt (stmt, ignore); |
6de9cd9a | 2471 | if (result) |
10a0d495 JJ |
2472 | { |
2473 | if (ignore) | |
2474 | STRIP_NOPS (result); | |
2475 | return result; | |
2476 | } | |
a32e70c3 RS |
2477 | |
2478 | /* Ignore MD builtins. */ | |
726a989a | 2479 | callee = gimple_call_fndecl (stmt); |
a32e70c3 RS |
2480 | if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_MD) |
2481 | return NULL_TREE; | |
6de9cd9a DN |
2482 | |
2483 | /* If the builtin could not be folded, and it has no argument list, | |
2484 | we're done. */ | |
726a989a | 2485 | nargs = gimple_call_num_args (stmt); |
5039610b | 2486 | if (nargs == 0) |
6de9cd9a DN |
2487 | return NULL_TREE; |
2488 | ||
2489 | /* Limit the work only for builtins we know how to simplify. */ | |
2490 | switch (DECL_FUNCTION_CODE (callee)) | |
2491 | { | |
2492 | case BUILT_IN_STRLEN: | |
2493 | case BUILT_IN_FPUTS: | |
2494 | case BUILT_IN_FPUTS_UNLOCKED: | |
d9cc481a | 2495 | arg_idx = 0; |
10a0d495 | 2496 | type = 0; |
6de9cd9a DN |
2497 | break; |
2498 | case BUILT_IN_STRCPY: | |
2499 | case BUILT_IN_STRNCPY: | |
d9cc481a | 2500 | arg_idx = 1; |
10a0d495 JJ |
2501 | type = 0; |
2502 | break; | |
2503 | case BUILT_IN_MEMCPY_CHK: | |
2504 | case BUILT_IN_MEMPCPY_CHK: | |
2505 | case BUILT_IN_MEMMOVE_CHK: | |
2506 | case BUILT_IN_MEMSET_CHK: | |
2507 | case BUILT_IN_STRNCPY_CHK: | |
d9cc481a | 2508 | arg_idx = 2; |
10a0d495 JJ |
2509 | type = 2; |
2510 | break; | |
2511 | case BUILT_IN_STRCPY_CHK: | |
2512 | case BUILT_IN_STPCPY_CHK: | |
d9cc481a | 2513 | arg_idx = 1; |
10a0d495 JJ |
2514 | type = 1; |
2515 | break; | |
2516 | case BUILT_IN_SNPRINTF_CHK: | |
2517 | case BUILT_IN_VSNPRINTF_CHK: | |
d9cc481a | 2518 | arg_idx = 1; |
10a0d495 | 2519 | type = 2; |
6de9cd9a DN |
2520 | break; |
2521 | default: | |
2522 | return NULL_TREE; | |
2523 | } | |
2524 | ||
f6ab27bb JJ |
2525 | if (arg_idx >= nargs) |
2526 | return NULL_TREE; | |
2527 | ||
6de9cd9a | 2528 | /* Try to use the dataflow information gathered by the CCP process. */ |
8bdbfff5 | 2529 | visited = BITMAP_ALLOC (NULL); |
d9cc481a | 2530 | bitmap_clear (visited); |
6de9cd9a | 2531 | |
10a0d495 | 2532 | memset (val, 0, sizeof (val)); |
d9cc481a AN |
2533 | a = gimple_call_arg (stmt, arg_idx); |
2534 | if (!get_maxval_strlen (a, &val[arg_idx], visited, type)) | |
2535 | val[arg_idx] = NULL_TREE; | |
6de9cd9a | 2536 | |
8bdbfff5 | 2537 | BITMAP_FREE (visited); |
6de9cd9a | 2538 | |
a32e70c3 | 2539 | result = NULL_TREE; |
6de9cd9a DN |
2540 | switch (DECL_FUNCTION_CODE (callee)) |
2541 | { | |
2542 | case BUILT_IN_STRLEN: | |
f6ab27bb | 2543 | if (val[0] && nargs == 1) |
6de9cd9a | 2544 | { |
726a989a RB |
2545 | tree new_val = |
2546 | fold_convert (TREE_TYPE (gimple_call_lhs (stmt)), val[0]); | |
6de9cd9a DN |
2547 | |
2548 | /* If the result is not a valid gimple value, or not a cast | |
2549 | of a valid gimple value, then we can not use the result. */ | |
c22940cd TN |
2550 | if (is_gimple_val (new_val) |
2551 | || (is_gimple_cast (new_val) | |
2552 | && is_gimple_val (TREE_OPERAND (new_val, 0)))) | |
2553 | return new_val; | |
6de9cd9a | 2554 | } |
a32e70c3 RS |
2555 | break; |
2556 | ||
6de9cd9a | 2557 | case BUILT_IN_STRCPY: |
5039610b SL |
2558 | if (val[1] && is_gimple_val (val[1]) && nargs == 2) |
2559 | result = fold_builtin_strcpy (callee, | |
726a989a RB |
2560 | gimple_call_arg (stmt, 0), |
2561 | gimple_call_arg (stmt, 1), | |
5039610b | 2562 | val[1]); |
a32e70c3 RS |
2563 | break; |
2564 | ||
6de9cd9a | 2565 | case BUILT_IN_STRNCPY: |
5039610b SL |
2566 | if (val[1] && is_gimple_val (val[1]) && nargs == 3) |
2567 | result = fold_builtin_strncpy (callee, | |
726a989a RB |
2568 | gimple_call_arg (stmt, 0), |
2569 | gimple_call_arg (stmt, 1), | |
2570 | gimple_call_arg (stmt, 2), | |
5039610b | 2571 | val[1]); |
a32e70c3 RS |
2572 | break; |
2573 | ||
6de9cd9a | 2574 | case BUILT_IN_FPUTS: |
f6ab27bb JJ |
2575 | if (nargs == 2) |
2576 | result = fold_builtin_fputs (gimple_call_arg (stmt, 0), | |
2577 | gimple_call_arg (stmt, 1), | |
2578 | ignore, false, val[0]); | |
a32e70c3 RS |
2579 | break; |
2580 | ||
6de9cd9a | 2581 | case BUILT_IN_FPUTS_UNLOCKED: |
f6ab27bb JJ |
2582 | if (nargs == 2) |
2583 | result = fold_builtin_fputs (gimple_call_arg (stmt, 0), | |
2584 | gimple_call_arg (stmt, 1), | |
2585 | ignore, true, val[0]); | |
10a0d495 JJ |
2586 | break; |
2587 | ||
2588 | case BUILT_IN_MEMCPY_CHK: | |
2589 | case BUILT_IN_MEMPCPY_CHK: | |
2590 | case BUILT_IN_MEMMOVE_CHK: | |
2591 | case BUILT_IN_MEMSET_CHK: | |
f6ab27bb | 2592 | if (val[2] && is_gimple_val (val[2]) && nargs == 4) |
5039610b | 2593 | result = fold_builtin_memory_chk (callee, |
726a989a RB |
2594 | gimple_call_arg (stmt, 0), |
2595 | gimple_call_arg (stmt, 1), | |
2596 | gimple_call_arg (stmt, 2), | |
2597 | gimple_call_arg (stmt, 3), | |
5039610b | 2598 | val[2], ignore, |
10a0d495 JJ |
2599 | DECL_FUNCTION_CODE (callee)); |
2600 | break; | |
2601 | ||
2602 | case BUILT_IN_STRCPY_CHK: | |
2603 | case BUILT_IN_STPCPY_CHK: | |
f6ab27bb | 2604 | if (val[1] && is_gimple_val (val[1]) && nargs == 3) |
5039610b | 2605 | result = fold_builtin_stxcpy_chk (callee, |
726a989a RB |
2606 | gimple_call_arg (stmt, 0), |
2607 | gimple_call_arg (stmt, 1), | |
2608 | gimple_call_arg (stmt, 2), | |
5039610b | 2609 | val[1], ignore, |
10a0d495 JJ |
2610 | DECL_FUNCTION_CODE (callee)); |
2611 | break; | |
2612 | ||
2613 | case BUILT_IN_STRNCPY_CHK: | |
f6ab27bb | 2614 | if (val[2] && is_gimple_val (val[2]) && nargs == 4) |
726a989a RB |
2615 | result = fold_builtin_strncpy_chk (gimple_call_arg (stmt, 0), |
2616 | gimple_call_arg (stmt, 1), | |
2617 | gimple_call_arg (stmt, 2), | |
2618 | gimple_call_arg (stmt, 3), | |
5039610b | 2619 | val[2]); |
10a0d495 JJ |
2620 | break; |
2621 | ||
2622 | case BUILT_IN_SNPRINTF_CHK: | |
2623 | case BUILT_IN_VSNPRINTF_CHK: | |
2624 | if (val[1] && is_gimple_val (val[1])) | |
726a989a RB |
2625 | result = gimple_fold_builtin_snprintf_chk (stmt, val[1], |
2626 | DECL_FUNCTION_CODE (callee)); | |
a32e70c3 | 2627 | break; |
6de9cd9a DN |
2628 | |
2629 | default: | |
1e128c5f | 2630 | gcc_unreachable (); |
6de9cd9a DN |
2631 | } |
2632 | ||
a32e70c3 | 2633 | if (result && ignore) |
9675412f | 2634 | result = fold_ignored_result (result); |
a32e70c3 | 2635 | return result; |
6de9cd9a DN |
2636 | } |
2637 | ||
726a989a RB |
2638 | /* Attempt to fold an assignment statement pointed-to by SI. Returns a |
2639 | replacement rhs for the statement or NULL_TREE if no simplification | |
2640 | could be made. It is assumed that the operands have been previously | |
2641 | folded. */ | |
2642 | ||
2643 | static tree | |
2644 | fold_gimple_assign (gimple_stmt_iterator *si) | |
2645 | { | |
2646 | gimple stmt = gsi_stmt (*si); | |
2647 | enum tree_code subcode = gimple_assign_rhs_code (stmt); | |
2648 | ||
2649 | tree result = NULL; | |
2650 | ||
2651 | switch (get_gimple_rhs_class (subcode)) | |
2652 | { | |
2653 | case GIMPLE_SINGLE_RHS: | |
2654 | { | |
2655 | tree rhs = gimple_assign_rhs1 (stmt); | |
2656 | ||
2657 | /* Try to fold a conditional expression. */ | |
2658 | if (TREE_CODE (rhs) == COND_EXPR) | |
2659 | { | |
2660 | tree temp = fold (COND_EXPR_COND (rhs)); | |
2661 | if (temp != COND_EXPR_COND (rhs)) | |
2662 | result = fold_build3 (COND_EXPR, TREE_TYPE (rhs), temp, | |
2663 | COND_EXPR_THEN (rhs), COND_EXPR_ELSE (rhs)); | |
2664 | } | |
2665 | ||
2666 | /* If we couldn't fold the RHS, hand over to the generic | |
2667 | fold routines. */ | |
2668 | if (result == NULL_TREE) | |
2669 | result = fold (rhs); | |
2670 | ||
2671 | /* Strip away useless type conversions. Both the NON_LVALUE_EXPR | |
2672 | that may have been added by fold, and "useless" type | |
2673 | conversions that might now be apparent due to propagation. */ | |
2674 | STRIP_USELESS_TYPE_CONVERSION (result); | |
2675 | ||
2676 | if (result != rhs && valid_gimple_rhs_p (result)) | |
2677 | return result; | |
2678 | else | |
2679 | /* It is possible that fold_stmt_r simplified the RHS. | |
2680 | Make sure that the subcode of this statement still | |
2681 | reflects the principal operator of the rhs operand. */ | |
2682 | return rhs; | |
2683 | } | |
2684 | break; | |
2685 | ||
2686 | case GIMPLE_UNARY_RHS: | |
ff8b183b RG |
2687 | { |
2688 | tree rhs = gimple_assign_rhs1 (stmt); | |
726a989a | 2689 | |
ff8b183b RG |
2690 | result = fold_unary (subcode, gimple_expr_type (stmt), rhs); |
2691 | if (result) | |
2692 | { | |
2693 | /* If the operation was a conversion do _not_ mark a | |
2694 | resulting constant with TREE_OVERFLOW if the original | |
2695 | constant was not. These conversions have implementation | |
2696 | defined behavior and retaining the TREE_OVERFLOW flag | |
2697 | here would confuse later passes such as VRP. */ | |
2698 | if (CONVERT_EXPR_CODE_P (subcode) | |
2699 | && TREE_CODE (result) == INTEGER_CST | |
2700 | && TREE_CODE (rhs) == INTEGER_CST) | |
2701 | TREE_OVERFLOW (result) = TREE_OVERFLOW (rhs); | |
2702 | ||
2703 | STRIP_USELESS_TYPE_CONVERSION (result); | |
2704 | if (valid_gimple_rhs_p (result)) | |
2705 | return result; | |
2706 | } | |
2707 | else if (CONVERT_EXPR_CODE_P (subcode) | |
2708 | && POINTER_TYPE_P (gimple_expr_type (stmt)) | |
2709 | && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))) | |
2710 | { | |
2711 | tree type = gimple_expr_type (stmt); | |
2712 | tree t = maybe_fold_offset_to_address (gimple_assign_rhs1 (stmt), | |
2713 | integer_zero_node, type); | |
2714 | if (t) | |
2715 | return t; | |
2716 | } | |
2717 | } | |
726a989a RB |
2718 | break; |
2719 | ||
2720 | case GIMPLE_BINARY_RHS: | |
2721 | /* Try to fold pointer addition. */ | |
2722 | if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR) | |
66e8b99c RG |
2723 | { |
2724 | tree type = TREE_TYPE (gimple_assign_rhs1 (stmt)); | |
2725 | if (TREE_CODE (TREE_TYPE (type)) == ARRAY_TYPE) | |
2726 | { | |
2727 | type = build_pointer_type (TREE_TYPE (TREE_TYPE (type))); | |
2728 | if (!useless_type_conversion_p | |
2729 | (TREE_TYPE (gimple_assign_lhs (stmt)), type)) | |
2730 | type = TREE_TYPE (gimple_assign_rhs1 (stmt)); | |
2731 | } | |
2732 | result = maybe_fold_stmt_addition (type, | |
2733 | gimple_assign_rhs1 (stmt), | |
2734 | gimple_assign_rhs2 (stmt)); | |
2735 | } | |
726a989a RB |
2736 | |
2737 | if (!result) | |
2738 | result = fold_binary (subcode, | |
2739 | TREE_TYPE (gimple_assign_lhs (stmt)), | |
2740 | gimple_assign_rhs1 (stmt), | |
2741 | gimple_assign_rhs2 (stmt)); | |
2742 | ||
2743 | if (result) | |
2744 | { | |
2745 | STRIP_USELESS_TYPE_CONVERSION (result); | |
2746 | if (valid_gimple_rhs_p (result)) | |
2747 | return result; | |
001003c2 PB |
2748 | |
2749 | /* Fold might have produced non-GIMPLE, so if we trust it blindly | |
2750 | we lose canonicalization opportunities. Do not go again | |
2751 | through fold here though, or the same non-GIMPLE will be | |
2752 | produced. */ | |
2753 | if (commutative_tree_code (subcode) | |
2754 | && tree_swap_operands_p (gimple_assign_rhs1 (stmt), | |
2755 | gimple_assign_rhs2 (stmt), false)) | |
2756 | return build2 (subcode, TREE_TYPE (gimple_assign_lhs (stmt)), | |
2757 | gimple_assign_rhs2 (stmt), | |
2758 | gimple_assign_rhs1 (stmt)); | |
726a989a RB |
2759 | } |
2760 | break; | |
2761 | ||
2762 | case GIMPLE_INVALID_RHS: | |
2763 | gcc_unreachable (); | |
2764 | } | |
2765 | ||
2766 | return NULL_TREE; | |
2767 | } | |
2768 | ||
2769 | /* Attempt to fold a conditional statement. Return true if any changes were | |
2770 | made. We only attempt to fold the condition expression, and do not perform | |
2771 | any transformation that would require alteration of the cfg. It is | |
2772 | assumed that the operands have been previously folded. */ | |
2773 | ||
2774 | static bool | |
2775 | fold_gimple_cond (gimple stmt) | |
2776 | { | |
2777 | tree result = fold_binary (gimple_cond_code (stmt), | |
2778 | boolean_type_node, | |
2779 | gimple_cond_lhs (stmt), | |
2780 | gimple_cond_rhs (stmt)); | |
2781 | ||
2782 | if (result) | |
2783 | { | |
2784 | STRIP_USELESS_TYPE_CONVERSION (result); | |
2785 | if (is_gimple_condexpr (result) && valid_gimple_rhs_p (result)) | |
2786 | { | |
2787 | gimple_cond_set_condition_from_tree (stmt, result); | |
2788 | return true; | |
2789 | } | |
2790 | } | |
2791 | ||
2792 | return false; | |
2793 | } | |
2794 | ||
2795 | ||
2796 | /* Attempt to fold a call statement referenced by the statement iterator GSI. | |
2797 | The statement may be replaced by another statement, e.g., if the call | |
2798 | simplifies to a constant value. Return true if any changes were made. | |
2799 | It is assumed that the operands have been previously folded. */ | |
2800 | ||
2801 | static bool | |
2802 | fold_gimple_call (gimple_stmt_iterator *gsi) | |
2803 | { | |
2804 | gimple stmt = gsi_stmt (*gsi); | |
2805 | ||
2806 | tree callee = gimple_call_fndecl (stmt); | |
2807 | ||
2808 | /* Check for builtins that CCP can handle using information not | |
2809 | available in the generic fold routines. */ | |
2810 | if (callee && DECL_BUILT_IN (callee)) | |
2811 | { | |
2812 | tree result = ccp_fold_builtin (stmt); | |
2813 | ||
2814 | if (result) | |
2815 | return update_call_from_tree (gsi, result); | |
2816 | } | |
2817 | else | |
2818 | { | |
2819 | /* Check for resolvable OBJ_TYPE_REF. The only sorts we can resolve | |
2820 | here are when we've propagated the address of a decl into the | |
2821 | object slot. */ | |
2822 | /* ??? Should perhaps do this in fold proper. However, doing it | |
2823 | there requires that we create a new CALL_EXPR, and that requires | |
2824 | copying EH region info to the new node. Easier to just do it | |
2825 | here where we can just smash the call operand. */ | |
2826 | /* ??? Is there a good reason not to do this in fold_stmt_inplace? */ | |
2827 | callee = gimple_call_fn (stmt); | |
2828 | if (TREE_CODE (callee) == OBJ_TYPE_REF | |
2829 | && lang_hooks.fold_obj_type_ref | |
2830 | && TREE_CODE (OBJ_TYPE_REF_OBJECT (callee)) == ADDR_EXPR | |
2831 | && DECL_P (TREE_OPERAND | |
2832 | (OBJ_TYPE_REF_OBJECT (callee), 0))) | |
2833 | { | |
2834 | tree t; | |
2835 | ||
2836 | /* ??? Caution: Broken ADDR_EXPR semantics means that | |
2837 | looking at the type of the operand of the addr_expr | |
2838 | can yield an array type. See silly exception in | |
2839 | check_pointer_types_r. */ | |
2840 | t = TREE_TYPE (TREE_TYPE (OBJ_TYPE_REF_OBJECT (callee))); | |
2841 | t = lang_hooks.fold_obj_type_ref (callee, t); | |
2842 | if (t) | |
2843 | { | |
2844 | gimple_call_set_fn (stmt, t); | |
2845 | return true; | |
2846 | } | |
2847 | } | |
2848 | } | |
2849 | ||
2850 | return false; | |
2851 | } | |
6de9cd9a | 2852 | |
726a989a | 2853 | /* Fold the statement pointed to by GSI. In some cases, this function may |
750628d8 DN |
2854 | replace the whole statement with a new one. Returns true iff folding |
2855 | makes any changes. */ | |
6de9cd9a | 2856 | |
750628d8 | 2857 | bool |
726a989a | 2858 | fold_stmt (gimple_stmt_iterator *gsi) |
6de9cd9a | 2859 | { |
726a989a | 2860 | tree res; |
622f91ba | 2861 | struct fold_stmt_r_data fold_stmt_r_data; |
726a989a RB |
2862 | struct walk_stmt_info wi; |
2863 | ||
750628d8 | 2864 | bool changed = false; |
622f91ba JL |
2865 | bool inside_addr_expr = false; |
2866 | ||
726a989a | 2867 | gimple stmt = gsi_stmt (*gsi); |
6ac01510 ILT |
2868 | |
2869 | fold_stmt_r_data.stmt = stmt; | |
622f91ba JL |
2870 | fold_stmt_r_data.changed_p = &changed; |
2871 | fold_stmt_r_data.inside_addr_expr_p = &inside_addr_expr; | |
6de9cd9a | 2872 | |
726a989a RB |
2873 | memset (&wi, 0, sizeof (wi)); |
2874 | wi.info = &fold_stmt_r_data; | |
6de9cd9a | 2875 | |
726a989a RB |
2876 | /* Fold the individual operands. |
2877 | For example, fold instances of *&VAR into VAR, etc. */ | |
2878 | res = walk_gimple_op (stmt, fold_stmt_r, &wi); | |
2879 | gcc_assert (!res); | |
6de9cd9a | 2880 | |
726a989a RB |
2881 | /* Fold the main computation performed by the statement. */ |
2882 | switch (gimple_code (stmt)) | |
6de9cd9a | 2883 | { |
726a989a RB |
2884 | case GIMPLE_ASSIGN: |
2885 | { | |
2886 | tree new_rhs = fold_gimple_assign (gsi); | |
2887 | if (new_rhs != NULL_TREE) | |
2888 | { | |
2889 | gimple_assign_set_rhs_from_tree (gsi, new_rhs); | |
2890 | changed = true; | |
2891 | } | |
2892 | stmt = gsi_stmt (*gsi); | |
2893 | break; | |
2894 | } | |
2895 | case GIMPLE_COND: | |
2896 | changed |= fold_gimple_cond (stmt); | |
2897 | break; | |
2898 | case GIMPLE_CALL: | |
2899 | /* The entire statement may be replaced in this case. */ | |
2900 | changed |= fold_gimple_call (gsi); | |
2901 | break; | |
1809ff6b | 2902 | |
726a989a RB |
2903 | default: |
2904 | return changed; | |
2905 | break; | |
f255541f | 2906 | } |
6de9cd9a | 2907 | |
750628d8 | 2908 | return changed; |
6de9cd9a DN |
2909 | } |
2910 | ||
38965eb2 ZD |
2911 | /* Perform the minimal folding on statement STMT. Only operations like |
2912 | *&x created by constant propagation are handled. The statement cannot | |
726a989a RB |
2913 | be replaced with a new one. Return true if the statement was |
2914 | changed, false otherwise. */ | |
38965eb2 ZD |
2915 | |
2916 | bool | |
726a989a | 2917 | fold_stmt_inplace (gimple stmt) |
38965eb2 | 2918 | { |
726a989a | 2919 | tree res; |
622f91ba | 2920 | struct fold_stmt_r_data fold_stmt_r_data; |
726a989a RB |
2921 | struct walk_stmt_info wi; |
2922 | gimple_stmt_iterator si; | |
2923 | ||
38965eb2 | 2924 | bool changed = false; |
622f91ba JL |
2925 | bool inside_addr_expr = false; |
2926 | ||
6ac01510 | 2927 | fold_stmt_r_data.stmt = stmt; |
622f91ba JL |
2928 | fold_stmt_r_data.changed_p = &changed; |
2929 | fold_stmt_r_data.inside_addr_expr_p = &inside_addr_expr; | |
38965eb2 | 2930 | |
726a989a RB |
2931 | memset (&wi, 0, sizeof (wi)); |
2932 | wi.info = &fold_stmt_r_data; | |
2933 | ||
2934 | /* Fold the individual operands. | |
2935 | For example, fold instances of *&VAR into VAR, etc. | |
38965eb2 | 2936 | |
726a989a RB |
2937 | It appears that, at one time, maybe_fold_stmt_indirect |
2938 | would cause the walk to return non-null in order to | |
2939 | signal that the entire statement should be replaced with | |
2940 | a call to _builtin_trap. This functionality is currently | |
2941 | disabled, as noted in a FIXME, and cannot be supported here. */ | |
2942 | res = walk_gimple_op (stmt, fold_stmt_r, &wi); | |
2943 | gcc_assert (!res); | |
38965eb2 | 2944 | |
726a989a RB |
2945 | /* Fold the main computation performed by the statement. */ |
2946 | switch (gimple_code (stmt)) | |
2947 | { | |
2948 | case GIMPLE_ASSIGN: | |
2949 | { | |
2950 | unsigned old_num_ops; | |
2951 | tree new_rhs; | |
2952 | old_num_ops = gimple_num_ops (stmt); | |
2953 | si = gsi_for_stmt (stmt); | |
2954 | new_rhs = fold_gimple_assign (&si); | |
2955 | if (new_rhs != NULL_TREE | |
2956 | && get_gimple_rhs_num_ops (TREE_CODE (new_rhs)) < old_num_ops) | |
2957 | { | |
2958 | gimple_assign_set_rhs_from_tree (&si, new_rhs); | |
2959 | changed = true; | |
2960 | } | |
2961 | gcc_assert (gsi_stmt (si) == stmt); | |
2962 | break; | |
2963 | } | |
2964 | case GIMPLE_COND: | |
2965 | changed |= fold_gimple_cond (stmt); | |
2966 | break; | |
38965eb2 | 2967 | |
726a989a RB |
2968 | default: |
2969 | break; | |
2970 | } | |
38965eb2 ZD |
2971 | |
2972 | return changed; | |
2973 | } | |
726a989a | 2974 | |
cb8e078d JJ |
2975 | /* Try to optimize out __builtin_stack_restore. Optimize it out |
2976 | if there is another __builtin_stack_restore in the same basic | |
2977 | block and no calls or ASM_EXPRs are in between, or if this block's | |
2978 | only outgoing edge is to EXIT_BLOCK and there are no calls or | |
2979 | ASM_EXPRs after this __builtin_stack_restore. */ | |
2980 | ||
2981 | static tree | |
726a989a | 2982 | optimize_stack_restore (gimple_stmt_iterator i) |
cb8e078d | 2983 | { |
726a989a RB |
2984 | tree callee, rhs; |
2985 | gimple stmt, stack_save; | |
2986 | gimple_stmt_iterator stack_save_gsi; | |
2987 | ||
2988 | basic_block bb = gsi_bb (i); | |
2989 | gimple call = gsi_stmt (i); | |
cb8e078d | 2990 | |
726a989a RB |
2991 | if (gimple_code (call) != GIMPLE_CALL |
2992 | || gimple_call_num_args (call) != 1 | |
2993 | || TREE_CODE (gimple_call_arg (call, 0)) != SSA_NAME | |
2994 | || !POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call, 0)))) | |
cb8e078d JJ |
2995 | return NULL_TREE; |
2996 | ||
726a989a | 2997 | for (gsi_next (&i); !gsi_end_p (i); gsi_next (&i)) |
cb8e078d | 2998 | { |
726a989a RB |
2999 | stmt = gsi_stmt (i); |
3000 | if (gimple_code (stmt) == GIMPLE_ASM) | |
cb8e078d | 3001 | return NULL_TREE; |
726a989a | 3002 | if (gimple_code (stmt) != GIMPLE_CALL) |
cb8e078d JJ |
3003 | continue; |
3004 | ||
726a989a | 3005 | callee = gimple_call_fndecl (stmt); |
cb8e078d JJ |
3006 | if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) |
3007 | return NULL_TREE; | |
3008 | ||
3009 | if (DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_RESTORE) | |
3010 | break; | |
3011 | } | |
3012 | ||
726a989a | 3013 | if (gsi_end_p (i) |
cb8e078d JJ |
3014 | && (! single_succ_p (bb) |
3015 | || single_succ_edge (bb)->dest != EXIT_BLOCK_PTR)) | |
3016 | return NULL_TREE; | |
3017 | ||
726a989a RB |
3018 | stack_save = SSA_NAME_DEF_STMT (gimple_call_arg (call, 0)); |
3019 | if (gimple_code (stack_save) != GIMPLE_CALL | |
3020 | || gimple_call_lhs (stack_save) != gimple_call_arg (call, 0) | |
3021 | || stmt_could_throw_p (stack_save) | |
3022 | || !has_single_use (gimple_call_arg (call, 0))) | |
cb8e078d JJ |
3023 | return NULL_TREE; |
3024 | ||
726a989a | 3025 | callee = gimple_call_fndecl (stack_save); |
cb8e078d JJ |
3026 | if (!callee |
3027 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL | |
3028 | || DECL_FUNCTION_CODE (callee) != BUILT_IN_STACK_SAVE | |
726a989a | 3029 | || gimple_call_num_args (stack_save) != 0) |
cb8e078d JJ |
3030 | return NULL_TREE; |
3031 | ||
726a989a RB |
3032 | stack_save_gsi = gsi_for_stmt (stack_save); |
3033 | push_stmt_changes (gsi_stmt_ptr (&stack_save_gsi)); | |
3034 | rhs = build_int_cst (TREE_TYPE (gimple_call_arg (call, 0)), 0); | |
3035 | if (!update_call_from_tree (&stack_save_gsi, rhs)) | |
cb8e078d | 3036 | { |
726a989a | 3037 | discard_stmt_changes (gsi_stmt_ptr (&stack_save_gsi)); |
cb8e078d JJ |
3038 | return NULL_TREE; |
3039 | } | |
726a989a | 3040 | pop_stmt_changes (gsi_stmt_ptr (&stack_save_gsi)); |
cb8e078d | 3041 | |
726a989a | 3042 | /* No effect, so the statement will be deleted. */ |
cb8e078d JJ |
3043 | return integer_zero_node; |
3044 | } | |
726a989a | 3045 | |
d7bd8aeb JJ |
3046 | /* If va_list type is a simple pointer and nothing special is needed, |
3047 | optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0), | |
3048 | __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple | |
3049 | pointer assignment. */ | |
3050 | ||
3051 | static tree | |
726a989a | 3052 | optimize_stdarg_builtin (gimple call) |
d7bd8aeb | 3053 | { |
35cbb299 | 3054 | tree callee, lhs, rhs, cfun_va_list; |
d7bd8aeb JJ |
3055 | bool va_list_simple_ptr; |
3056 | ||
726a989a | 3057 | if (gimple_code (call) != GIMPLE_CALL) |
d7bd8aeb JJ |
3058 | return NULL_TREE; |
3059 | ||
726a989a | 3060 | callee = gimple_call_fndecl (call); |
35cbb299 KT |
3061 | |
3062 | cfun_va_list = targetm.fn_abi_va_list (callee); | |
3063 | va_list_simple_ptr = POINTER_TYPE_P (cfun_va_list) | |
3064 | && (TREE_TYPE (cfun_va_list) == void_type_node | |
3065 | || TREE_TYPE (cfun_va_list) == char_type_node); | |
3066 | ||
d7bd8aeb JJ |
3067 | switch (DECL_FUNCTION_CODE (callee)) |
3068 | { | |
3069 | case BUILT_IN_VA_START: | |
3070 | if (!va_list_simple_ptr | |
3071 | || targetm.expand_builtin_va_start != NULL | |
726a989a | 3072 | || built_in_decls[BUILT_IN_NEXT_ARG] == NULL) |
d7bd8aeb JJ |
3073 | return NULL_TREE; |
3074 | ||
726a989a | 3075 | if (gimple_call_num_args (call) != 2) |
d7bd8aeb JJ |
3076 | return NULL_TREE; |
3077 | ||
726a989a | 3078 | lhs = gimple_call_arg (call, 0); |
d7bd8aeb JJ |
3079 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) |
3080 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
35cbb299 | 3081 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
d7bd8aeb | 3082 | return NULL_TREE; |
726a989a | 3083 | |
d7bd8aeb JJ |
3084 | lhs = build_fold_indirect_ref (lhs); |
3085 | rhs = build_call_expr (built_in_decls[BUILT_IN_NEXT_ARG], | |
726a989a | 3086 | 1, integer_zero_node); |
d7bd8aeb JJ |
3087 | rhs = fold_convert (TREE_TYPE (lhs), rhs); |
3088 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); | |
3089 | ||
3090 | case BUILT_IN_VA_COPY: | |
3091 | if (!va_list_simple_ptr) | |
3092 | return NULL_TREE; | |
3093 | ||
726a989a | 3094 | if (gimple_call_num_args (call) != 2) |
d7bd8aeb JJ |
3095 | return NULL_TREE; |
3096 | ||
726a989a | 3097 | lhs = gimple_call_arg (call, 0); |
d7bd8aeb JJ |
3098 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) |
3099 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
35cbb299 | 3100 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
d7bd8aeb JJ |
3101 | return NULL_TREE; |
3102 | ||
3103 | lhs = build_fold_indirect_ref (lhs); | |
726a989a | 3104 | rhs = gimple_call_arg (call, 1); |
d7bd8aeb | 3105 | if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs)) |
35cbb299 | 3106 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
d7bd8aeb JJ |
3107 | return NULL_TREE; |
3108 | ||
3109 | rhs = fold_convert (TREE_TYPE (lhs), rhs); | |
3110 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); | |
3111 | ||
3112 | case BUILT_IN_VA_END: | |
726a989a | 3113 | /* No effect, so the statement will be deleted. */ |
d7bd8aeb JJ |
3114 | return integer_zero_node; |
3115 | ||
3116 | default: | |
3117 | gcc_unreachable (); | |
3118 | } | |
3119 | } | |
726a989a | 3120 | |
b28b1600 JJ |
3121 | /* Convert EXPR into a GIMPLE value suitable for substitution on the |
3122 | RHS of an assignment. Insert the necessary statements before | |
726a989a RB |
3123 | iterator *SI_P. The statement at *SI_P, which must be a GIMPLE_CALL |
3124 | is replaced. If the call is expected to produces a result, then it | |
3125 | is replaced by an assignment of the new RHS to the result variable. | |
3126 | If the result is to be ignored, then the call is replaced by a | |
3127 | GIMPLE_NOP. */ | |
b28b1600 | 3128 | |
726a989a RB |
3129 | static void |
3130 | gimplify_and_update_call_from_tree (gimple_stmt_iterator *si_p, tree expr) | |
b28b1600 | 3131 | { |
726a989a RB |
3132 | tree lhs; |
3133 | tree tmp = NULL_TREE; /* Silence warning. */ | |
3134 | gimple stmt, new_stmt; | |
3135 | gimple_stmt_iterator i; | |
3136 | gimple_seq stmts = gimple_seq_alloc(); | |
d406b663 | 3137 | struct gimplify_ctx gctx; |
b28b1600 | 3138 | |
726a989a RB |
3139 | stmt = gsi_stmt (*si_p); |
3140 | ||
3141 | gcc_assert (is_gimple_call (stmt)); | |
3142 | ||
3143 | lhs = gimple_call_lhs (stmt); | |
3144 | ||
d406b663 | 3145 | push_gimplify_context (&gctx); |
726a989a RB |
3146 | |
3147 | if (lhs == NULL_TREE) | |
3148 | gimplify_and_add (expr, &stmts); | |
3149 | else | |
2e929cf3 | 3150 | tmp = get_initialized_tmp_var (expr, &stmts, NULL); |
726a989a | 3151 | |
b28b1600 JJ |
3152 | pop_gimplify_context (NULL); |
3153 | ||
726a989a RB |
3154 | if (gimple_has_location (stmt)) |
3155 | annotate_all_with_location (stmts, gimple_location (stmt)); | |
f47c96aa | 3156 | |
b28b1600 | 3157 | /* The replacement can expose previously unreferenced variables. */ |
726a989a RB |
3158 | for (i = gsi_start (stmts); !gsi_end_p (i); gsi_next (&i)) |
3159 | { | |
3160 | new_stmt = gsi_stmt (i); | |
3161 | find_new_referenced_vars (new_stmt); | |
3162 | gsi_insert_before (si_p, new_stmt, GSI_NEW_STMT); | |
3163 | mark_symbols_for_renaming (new_stmt); | |
3164 | gsi_next (si_p); | |
3165 | } | |
3166 | ||
3167 | if (lhs == NULL_TREE) | |
3168 | new_stmt = gimple_build_nop (); | |
3169 | else | |
b28b1600 | 3170 | { |
726a989a RB |
3171 | new_stmt = gimple_build_assign (lhs, tmp); |
3172 | copy_virtual_operands (new_stmt, stmt); | |
3173 | move_ssa_defining_stmt_for_defs (new_stmt, stmt); | |
b28b1600 JJ |
3174 | } |
3175 | ||
726a989a RB |
3176 | gimple_set_location (new_stmt, gimple_location (stmt)); |
3177 | gsi_replace (si_p, new_stmt, false); | |
b28b1600 JJ |
3178 | } |
3179 | ||
6de9cd9a DN |
3180 | /* A simple pass that attempts to fold all builtin functions. This pass |
3181 | is run after we've propagated as many constants as we can. */ | |
3182 | ||
c2924966 | 3183 | static unsigned int |
6de9cd9a DN |
3184 | execute_fold_all_builtins (void) |
3185 | { | |
a7d6ba24 | 3186 | bool cfg_changed = false; |
6de9cd9a | 3187 | basic_block bb; |
7b0e48fb DB |
3188 | unsigned int todoflags = 0; |
3189 | ||
6de9cd9a DN |
3190 | FOR_EACH_BB (bb) |
3191 | { | |
726a989a RB |
3192 | gimple_stmt_iterator i; |
3193 | for (i = gsi_start_bb (bb); !gsi_end_p (i); ) | |
6de9cd9a | 3194 | { |
726a989a | 3195 | gimple stmt, old_stmt; |
6de9cd9a | 3196 | tree callee, result; |
10a0d495 | 3197 | enum built_in_function fcode; |
6de9cd9a | 3198 | |
726a989a RB |
3199 | stmt = gsi_stmt (i); |
3200 | ||
3201 | if (gimple_code (stmt) != GIMPLE_CALL) | |
10a0d495 | 3202 | { |
726a989a | 3203 | gsi_next (&i); |
10a0d495 JJ |
3204 | continue; |
3205 | } | |
726a989a | 3206 | callee = gimple_call_fndecl (stmt); |
6de9cd9a | 3207 | if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) |
10a0d495 | 3208 | { |
726a989a | 3209 | gsi_next (&i); |
10a0d495 JJ |
3210 | continue; |
3211 | } | |
3212 | fcode = DECL_FUNCTION_CODE (callee); | |
6de9cd9a | 3213 | |
726a989a | 3214 | result = ccp_fold_builtin (stmt); |
53a8f709 UB |
3215 | |
3216 | if (result) | |
726a989a | 3217 | gimple_remove_stmt_histograms (cfun, stmt); |
53a8f709 | 3218 | |
6de9cd9a DN |
3219 | if (!result) |
3220 | switch (DECL_FUNCTION_CODE (callee)) | |
3221 | { | |
3222 | case BUILT_IN_CONSTANT_P: | |
3223 | /* Resolve __builtin_constant_p. If it hasn't been | |
3224 | folded to integer_one_node by now, it's fairly | |
3225 | certain that the value simply isn't constant. */ | |
726a989a | 3226 | result = integer_zero_node; |
6de9cd9a DN |
3227 | break; |
3228 | ||
cb8e078d | 3229 | case BUILT_IN_STACK_RESTORE: |
726a989a | 3230 | result = optimize_stack_restore (i); |
d7bd8aeb JJ |
3231 | if (result) |
3232 | break; | |
726a989a | 3233 | gsi_next (&i); |
d7bd8aeb JJ |
3234 | continue; |
3235 | ||
3236 | case BUILT_IN_VA_START: | |
3237 | case BUILT_IN_VA_END: | |
3238 | case BUILT_IN_VA_COPY: | |
3239 | /* These shouldn't be folded before pass_stdarg. */ | |
726a989a | 3240 | result = optimize_stdarg_builtin (stmt); |
cb8e078d JJ |
3241 | if (result) |
3242 | break; | |
3243 | /* FALLTHRU */ | |
3244 | ||
6de9cd9a | 3245 | default: |
726a989a | 3246 | gsi_next (&i); |
6de9cd9a DN |
3247 | continue; |
3248 | } | |
3249 | ||
3250 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3251 | { | |
3252 | fprintf (dump_file, "Simplified\n "); | |
726a989a | 3253 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
6de9cd9a DN |
3254 | } |
3255 | ||
726a989a RB |
3256 | old_stmt = stmt; |
3257 | push_stmt_changes (gsi_stmt_ptr (&i)); | |
cfaab3a9 | 3258 | |
726a989a RB |
3259 | if (!update_call_from_tree (&i, result)) |
3260 | { | |
3261 | gimplify_and_update_call_from_tree (&i, result); | |
3262 | todoflags |= TODO_rebuild_alias; | |
3263 | } | |
cfaab3a9 | 3264 | |
726a989a RB |
3265 | stmt = gsi_stmt (i); |
3266 | pop_stmt_changes (gsi_stmt_ptr (&i)); | |
cfaab3a9 | 3267 | |
726a989a RB |
3268 | if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt) |
3269 | && gimple_purge_dead_eh_edges (bb)) | |
a7d6ba24 | 3270 | cfg_changed = true; |
6de9cd9a DN |
3271 | |
3272 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3273 | { | |
3274 | fprintf (dump_file, "to\n "); | |
726a989a | 3275 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
6de9cd9a DN |
3276 | fprintf (dump_file, "\n"); |
3277 | } | |
10a0d495 JJ |
3278 | |
3279 | /* Retry the same statement if it changed into another | |
3280 | builtin, there might be new opportunities now. */ | |
726a989a | 3281 | if (gimple_code (stmt) != GIMPLE_CALL) |
10a0d495 | 3282 | { |
726a989a | 3283 | gsi_next (&i); |
10a0d495 JJ |
3284 | continue; |
3285 | } | |
726a989a | 3286 | callee = gimple_call_fndecl (stmt); |
10a0d495 | 3287 | if (!callee |
726a989a | 3288 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL |
10a0d495 | 3289 | || DECL_FUNCTION_CODE (callee) == fcode) |
726a989a | 3290 | gsi_next (&i); |
6de9cd9a DN |
3291 | } |
3292 | } | |
7b0e48fb | 3293 | |
a7d6ba24 | 3294 | /* Delete unreachable blocks. */ |
7b0e48fb DB |
3295 | if (cfg_changed) |
3296 | todoflags |= TODO_cleanup_cfg; | |
3297 | ||
3298 | return todoflags; | |
6de9cd9a DN |
3299 | } |
3300 | ||
750628d8 | 3301 | |
8ddbbcae | 3302 | struct gimple_opt_pass pass_fold_builtins = |
6de9cd9a | 3303 | { |
8ddbbcae JH |
3304 | { |
3305 | GIMPLE_PASS, | |
6de9cd9a DN |
3306 | "fab", /* name */ |
3307 | NULL, /* gate */ | |
3308 | execute_fold_all_builtins, /* execute */ | |
3309 | NULL, /* sub */ | |
3310 | NULL, /* next */ | |
3311 | 0, /* static_pass_number */ | |
3312 | 0, /* tv_id */ | |
7faade0f | 3313 | PROP_cfg | PROP_ssa, /* properties_required */ |
6de9cd9a DN |
3314 | 0, /* properties_provided */ |
3315 | 0, /* properties_destroyed */ | |
3316 | 0, /* todo_flags_start */ | |
b28b1600 JJ |
3317 | TODO_dump_func |
3318 | | TODO_verify_ssa | |
8ddbbcae JH |
3319 | | TODO_update_ssa /* todo_flags_finish */ |
3320 | } | |
6de9cd9a | 3321 | }; |