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4ee9c684 | 1 | /* Conditional constant propagation pass for the GNU compiler. |
87c0a9fc | 2 | Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, |
3 | 2010 Free Software Foundation, Inc. | |
4ee9c684 | 4 | Adapted from original RTL SSA-CCP by Daniel Berlin <dberlin@dberlin.org> |
5 | Adapted to GIMPLE trees by Diego Novillo <dnovillo@redhat.com> | |
6 | ||
7 | This file is part of GCC. | |
48e1416a | 8 | |
4ee9c684 | 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 | |
8c4c00c1 | 11 | Free Software Foundation; either version 3, or (at your option) any |
4ee9c684 | 12 | later version. |
48e1416a | 13 | |
4ee9c684 | 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. | |
48e1416a | 18 | |
4ee9c684 | 19 | You should have received a copy of the GNU General Public License |
8c4c00c1 | 20 | along with GCC; see the file COPYING3. If not see |
21 | <http://www.gnu.org/licenses/>. */ | |
4ee9c684 | 22 | |
88dbf20f | 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 | ||
bfa30570 | 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. | |
88dbf20f | 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. | |
48e1416a | 66 | |
88dbf20f | 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 | |
4fb5e5ca | 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, | |
88dbf20f | 138 | |
4fb5e5ca | 139 | # a_5 = VDEF <a_4> |
88dbf20f | 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 | ||
bfa30570 | 149 | Note that the initial value of virtual operands is VARYING, not |
150 | UNDEFINED. Consider, for instance global variables: | |
88dbf20f | 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 | |
bfa30570 | 168 | would erroneously optimize the above into 'return 3;'. |
88dbf20f | 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. | |
4ee9c684 | 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" | |
4ee9c684 | 192 | #include "tree.h" |
41511585 | 193 | #include "flags.h" |
4ee9c684 | 194 | #include "tm_p.h" |
4ee9c684 | 195 | #include "basic-block.h" |
41511585 | 196 | #include "output.h" |
41511585 | 197 | #include "function.h" |
ce084dfc | 198 | #include "tree-pretty-print.h" |
199 | #include "gimple-pretty-print.h" | |
41511585 | 200 | #include "timevar.h" |
4ee9c684 | 201 | #include "tree-dump.h" |
41511585 | 202 | #include "tree-flow.h" |
4ee9c684 | 203 | #include "tree-pass.h" |
41511585 | 204 | #include "tree-ssa-propagate.h" |
5a4b7e1e | 205 | #include "value-prof.h" |
41511585 | 206 | #include "langhooks.h" |
8782adcf | 207 | #include "target.h" |
0b205f4c | 208 | #include "diagnostic-core.h" |
add6ee5e | 209 | #include "toplev.h" |
43fb76c1 | 210 | #include "dbgcnt.h" |
4ee9c684 | 211 | |
212 | ||
213 | /* Possible lattice values. */ | |
214 | typedef enum | |
215 | { | |
bfa30570 | 216 | UNINITIALIZED, |
4ee9c684 | 217 | UNDEFINED, |
218 | CONSTANT, | |
219 | VARYING | |
88dbf20f | 220 | } ccp_lattice_t; |
4ee9c684 | 221 | |
88dbf20f | 222 | /* Array of propagated constant values. After propagation, |
223 | CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If | |
224 | the constant is held in an SSA name representing a memory store | |
4fb5e5ca | 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). */ | |
20140406 | 228 | static prop_value_t *const_val; |
4ee9c684 | 229 | |
4af351a8 | 230 | static void canonicalize_float_value (prop_value_t *); |
6688f8ec | 231 | static bool ccp_fold_stmt (gimple_stmt_iterator *); |
4af351a8 | 232 | |
88dbf20f | 233 | /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */ |
01406fc0 | 234 | |
235 | static void | |
88dbf20f | 236 | dump_lattice_value (FILE *outf, const char *prefix, prop_value_t val) |
01406fc0 | 237 | { |
41511585 | 238 | switch (val.lattice_val) |
01406fc0 | 239 | { |
88dbf20f | 240 | case UNINITIALIZED: |
241 | fprintf (outf, "%sUNINITIALIZED", prefix); | |
242 | break; | |
41511585 | 243 | case UNDEFINED: |
244 | fprintf (outf, "%sUNDEFINED", prefix); | |
245 | break; | |
246 | case VARYING: | |
247 | fprintf (outf, "%sVARYING", prefix); | |
248 | break; | |
41511585 | 249 | case CONSTANT: |
250 | fprintf (outf, "%sCONSTANT ", prefix); | |
88dbf20f | 251 | print_generic_expr (outf, val.value, dump_flags); |
41511585 | 252 | break; |
253 | default: | |
8c0963c4 | 254 | gcc_unreachable (); |
41511585 | 255 | } |
01406fc0 | 256 | } |
4ee9c684 | 257 | |
4ee9c684 | 258 | |
88dbf20f | 259 | /* Print lattice value VAL to stderr. */ |
260 | ||
261 | void debug_lattice_value (prop_value_t val); | |
262 | ||
4b987fac | 263 | DEBUG_FUNCTION void |
88dbf20f | 264 | debug_lattice_value (prop_value_t val) |
265 | { | |
266 | dump_lattice_value (stderr, "", val); | |
267 | fprintf (stderr, "\n"); | |
268 | } | |
4ee9c684 | 269 | |
4ee9c684 | 270 | |
88dbf20f | 271 | /* Compute a default value for variable VAR and store it in the |
272 | CONST_VAL array. The following rules are used to get default | |
273 | values: | |
01406fc0 | 274 | |
88dbf20f | 275 | 1- Global and static variables that are declared constant are |
276 | considered CONSTANT. | |
277 | ||
278 | 2- Any other value is considered UNDEFINED. This is useful when | |
41511585 | 279 | considering PHI nodes. PHI arguments that are undefined do not |
280 | change the constant value of the PHI node, which allows for more | |
88dbf20f | 281 | constants to be propagated. |
4ee9c684 | 282 | |
8883e700 | 283 | 3- Variables defined by statements other than assignments and PHI |
88dbf20f | 284 | nodes are considered VARYING. |
4ee9c684 | 285 | |
8883e700 | 286 | 4- Initial values of variables that are not GIMPLE registers are |
bfa30570 | 287 | considered VARYING. */ |
4ee9c684 | 288 | |
88dbf20f | 289 | static prop_value_t |
290 | get_default_value (tree var) | |
291 | { | |
292 | tree sym = SSA_NAME_VAR (var); | |
61207d43 | 293 | prop_value_t val = { UNINITIALIZED, NULL_TREE }; |
8edeb88b | 294 | gimple stmt; |
295 | ||
296 | stmt = SSA_NAME_DEF_STMT (var); | |
297 | ||
298 | if (gimple_nop_p (stmt)) | |
4ee9c684 | 299 | { |
8edeb88b | 300 | /* Variables defined by an empty statement are those used |
301 | before being initialized. If VAR is a local variable, we | |
302 | can assume initially that it is UNDEFINED, otherwise we must | |
303 | consider it VARYING. */ | |
524a0531 | 304 | if (is_gimple_reg (sym) |
305 | && TREE_CODE (sym) == VAR_DECL) | |
8edeb88b | 306 | val.lattice_val = UNDEFINED; |
307 | else | |
308 | val.lattice_val = VARYING; | |
4ee9c684 | 309 | } |
8edeb88b | 310 | else if (is_gimple_assign (stmt) |
311 | /* Value-returning GIMPLE_CALL statements assign to | |
312 | a variable, and are treated similarly to GIMPLE_ASSIGN. */ | |
313 | || (is_gimple_call (stmt) | |
314 | && gimple_call_lhs (stmt) != NULL_TREE) | |
315 | || gimple_code (stmt) == GIMPLE_PHI) | |
41511585 | 316 | { |
8edeb88b | 317 | tree cst; |
318 | if (gimple_assign_single_p (stmt) | |
319 | && DECL_P (gimple_assign_rhs1 (stmt)) | |
320 | && (cst = get_symbol_constant_value (gimple_assign_rhs1 (stmt)))) | |
88dbf20f | 321 | { |
8edeb88b | 322 | val.lattice_val = CONSTANT; |
323 | val.value = cst; | |
88dbf20f | 324 | } |
325 | else | |
8edeb88b | 326 | /* Any other variable defined by an assignment or a PHI node |
327 | is considered UNDEFINED. */ | |
328 | val.lattice_val = UNDEFINED; | |
329 | } | |
330 | else | |
331 | { | |
332 | /* Otherwise, VAR will never take on a constant value. */ | |
333 | val.lattice_val = VARYING; | |
41511585 | 334 | } |
4ee9c684 | 335 | |
41511585 | 336 | return val; |
337 | } | |
4ee9c684 | 338 | |
4ee9c684 | 339 | |
bfa30570 | 340 | /* Get the constant value associated with variable VAR. */ |
4ee9c684 | 341 | |
bfa30570 | 342 | static inline prop_value_t * |
343 | get_value (tree var) | |
88dbf20f | 344 | { |
e004838d | 345 | prop_value_t *val; |
bfa30570 | 346 | |
e004838d | 347 | if (const_val == NULL) |
348 | return NULL; | |
349 | ||
350 | val = &const_val[SSA_NAME_VERSION (var)]; | |
bfa30570 | 351 | if (val->lattice_val == UNINITIALIZED) |
4ee9c684 | 352 | *val = get_default_value (var); |
353 | ||
4af351a8 | 354 | canonicalize_float_value (val); |
355 | ||
4ee9c684 | 356 | return val; |
357 | } | |
358 | ||
bfa30570 | 359 | /* Sets the value associated with VAR to VARYING. */ |
360 | ||
361 | static inline void | |
362 | set_value_varying (tree var) | |
363 | { | |
364 | prop_value_t *val = &const_val[SSA_NAME_VERSION (var)]; | |
365 | ||
366 | val->lattice_val = VARYING; | |
367 | val->value = NULL_TREE; | |
bfa30570 | 368 | } |
4ee9c684 | 369 | |
b31eb493 | 370 | /* For float types, modify the value of VAL to make ccp work correctly |
371 | for non-standard values (-0, NaN): | |
372 | ||
373 | If HONOR_SIGNED_ZEROS is false, and VAL = -0, we canonicalize it to 0. | |
374 | If HONOR_NANS is false, and VAL is NaN, we canonicalize it to UNDEFINED. | |
375 | This is to fix the following problem (see PR 29921): Suppose we have | |
376 | ||
377 | x = 0.0 * y | |
378 | ||
379 | and we set value of y to NaN. This causes value of x to be set to NaN. | |
380 | When we later determine that y is in fact VARYING, fold uses the fact | |
381 | that HONOR_NANS is false, and we try to change the value of x to 0, | |
382 | causing an ICE. With HONOR_NANS being false, the real appearance of | |
383 | NaN would cause undefined behavior, though, so claiming that y (and x) | |
384 | are UNDEFINED initially is correct. */ | |
385 | ||
386 | static void | |
387 | canonicalize_float_value (prop_value_t *val) | |
388 | { | |
389 | enum machine_mode mode; | |
390 | tree type; | |
391 | REAL_VALUE_TYPE d; | |
392 | ||
393 | if (val->lattice_val != CONSTANT | |
394 | || TREE_CODE (val->value) != REAL_CST) | |
395 | return; | |
396 | ||
397 | d = TREE_REAL_CST (val->value); | |
398 | type = TREE_TYPE (val->value); | |
399 | mode = TYPE_MODE (type); | |
400 | ||
401 | if (!HONOR_SIGNED_ZEROS (mode) | |
402 | && REAL_VALUE_MINUS_ZERO (d)) | |
403 | { | |
404 | val->value = build_real (type, dconst0); | |
405 | return; | |
406 | } | |
407 | ||
408 | if (!HONOR_NANS (mode) | |
409 | && REAL_VALUE_ISNAN (d)) | |
410 | { | |
411 | val->lattice_val = UNDEFINED; | |
412 | val->value = NULL; | |
b31eb493 | 413 | return; |
414 | } | |
415 | } | |
416 | ||
88dbf20f | 417 | /* Set the value for variable VAR to NEW_VAL. Return true if the new |
418 | value is different from VAR's previous value. */ | |
4ee9c684 | 419 | |
41511585 | 420 | static bool |
88dbf20f | 421 | set_lattice_value (tree var, prop_value_t new_val) |
4ee9c684 | 422 | { |
bfa30570 | 423 | prop_value_t *old_val = get_value (var); |
88dbf20f | 424 | |
b31eb493 | 425 | canonicalize_float_value (&new_val); |
426 | ||
88dbf20f | 427 | /* Lattice transitions must always be monotonically increasing in |
bfa30570 | 428 | value. If *OLD_VAL and NEW_VAL are the same, return false to |
429 | inform the caller that this was a non-transition. */ | |
430 | ||
aecfc21d | 431 | gcc_assert (old_val->lattice_val < new_val.lattice_val |
88dbf20f | 432 | || (old_val->lattice_val == new_val.lattice_val |
aecfc21d | 433 | && ((!old_val->value && !new_val.value) |
61207d43 | 434 | || operand_equal_p (old_val->value, new_val.value, 0)))); |
88dbf20f | 435 | |
436 | if (old_val->lattice_val != new_val.lattice_val) | |
4ee9c684 | 437 | { |
41511585 | 438 | if (dump_file && (dump_flags & TDF_DETAILS)) |
439 | { | |
88dbf20f | 440 | dump_lattice_value (dump_file, "Lattice value changed to ", new_val); |
bfa30570 | 441 | fprintf (dump_file, ". Adding SSA edges to worklist.\n"); |
41511585 | 442 | } |
443 | ||
88dbf20f | 444 | *old_val = new_val; |
445 | ||
bfa30570 | 446 | gcc_assert (new_val.lattice_val != UNDEFINED); |
447 | return true; | |
4ee9c684 | 448 | } |
41511585 | 449 | |
450 | return false; | |
4ee9c684 | 451 | } |
452 | ||
453 | ||
88dbf20f | 454 | /* Return the likely CCP lattice value for STMT. |
4ee9c684 | 455 | |
41511585 | 456 | If STMT has no operands, then return CONSTANT. |
4ee9c684 | 457 | |
d61b9af3 | 458 | Else if undefinedness of operands of STMT cause its value to be |
459 | undefined, then return UNDEFINED. | |
4ee9c684 | 460 | |
41511585 | 461 | Else if any operands of STMT are constants, then return CONSTANT. |
4ee9c684 | 462 | |
41511585 | 463 | Else return VARYING. */ |
4ee9c684 | 464 | |
88dbf20f | 465 | static ccp_lattice_t |
75a70cf9 | 466 | likely_value (gimple stmt) |
41511585 | 467 | { |
d61b9af3 | 468 | bool has_constant_operand, has_undefined_operand, all_undefined_operands; |
41511585 | 469 | tree use; |
470 | ssa_op_iter iter; | |
8edeb88b | 471 | unsigned i; |
4ee9c684 | 472 | |
590c3166 | 473 | enum gimple_code code = gimple_code (stmt); |
75a70cf9 | 474 | |
475 | /* This function appears to be called only for assignments, calls, | |
476 | conditionals, and switches, due to the logic in visit_stmt. */ | |
477 | gcc_assert (code == GIMPLE_ASSIGN | |
478 | || code == GIMPLE_CALL | |
479 | || code == GIMPLE_COND | |
480 | || code == GIMPLE_SWITCH); | |
88dbf20f | 481 | |
482 | /* If the statement has volatile operands, it won't fold to a | |
483 | constant value. */ | |
75a70cf9 | 484 | if (gimple_has_volatile_ops (stmt)) |
88dbf20f | 485 | return VARYING; |
486 | ||
75a70cf9 | 487 | /* Arrive here for more complex cases. */ |
bfa30570 | 488 | has_constant_operand = false; |
d61b9af3 | 489 | has_undefined_operand = false; |
490 | all_undefined_operands = true; | |
8edeb88b | 491 | FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE) |
41511585 | 492 | { |
bfa30570 | 493 | prop_value_t *val = get_value (use); |
41511585 | 494 | |
bfa30570 | 495 | if (val->lattice_val == UNDEFINED) |
d61b9af3 | 496 | has_undefined_operand = true; |
497 | else | |
498 | all_undefined_operands = false; | |
88dbf20f | 499 | |
41511585 | 500 | if (val->lattice_val == CONSTANT) |
bfa30570 | 501 | has_constant_operand = true; |
4ee9c684 | 502 | } |
41511585 | 503 | |
dd277d48 | 504 | /* There may be constants in regular rhs operands. For calls we |
505 | have to ignore lhs, fndecl and static chain, otherwise only | |
506 | the lhs. */ | |
507 | for (i = (is_gimple_call (stmt) ? 2 : 0) + gimple_has_lhs (stmt); | |
8edeb88b | 508 | i < gimple_num_ops (stmt); ++i) |
509 | { | |
510 | tree op = gimple_op (stmt, i); | |
511 | if (!op || TREE_CODE (op) == SSA_NAME) | |
512 | continue; | |
513 | if (is_gimple_min_invariant (op)) | |
514 | has_constant_operand = true; | |
515 | } | |
516 | ||
87c0a9fc | 517 | if (has_constant_operand) |
518 | all_undefined_operands = false; | |
519 | ||
d61b9af3 | 520 | /* If the operation combines operands like COMPLEX_EXPR make sure to |
521 | not mark the result UNDEFINED if only one part of the result is | |
522 | undefined. */ | |
75a70cf9 | 523 | if (has_undefined_operand && all_undefined_operands) |
d61b9af3 | 524 | return UNDEFINED; |
75a70cf9 | 525 | else if (code == GIMPLE_ASSIGN && has_undefined_operand) |
d61b9af3 | 526 | { |
75a70cf9 | 527 | switch (gimple_assign_rhs_code (stmt)) |
d61b9af3 | 528 | { |
529 | /* Unary operators are handled with all_undefined_operands. */ | |
530 | case PLUS_EXPR: | |
531 | case MINUS_EXPR: | |
d61b9af3 | 532 | case POINTER_PLUS_EXPR: |
d61b9af3 | 533 | /* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected. |
534 | Not bitwise operators, one VARYING operand may specify the | |
535 | result completely. Not logical operators for the same reason. | |
05a936a0 | 536 | Not COMPLEX_EXPR as one VARYING operand makes the result partly |
537 | not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because | |
538 | the undefined operand may be promoted. */ | |
d61b9af3 | 539 | return UNDEFINED; |
540 | ||
541 | default: | |
542 | ; | |
543 | } | |
544 | } | |
545 | /* If there was an UNDEFINED operand but the result may be not UNDEFINED | |
546 | fall back to VARYING even if there were CONSTANT operands. */ | |
547 | if (has_undefined_operand) | |
548 | return VARYING; | |
549 | ||
8edeb88b | 550 | /* We do not consider virtual operands here -- load from read-only |
551 | memory may have only VARYING virtual operands, but still be | |
552 | constant. */ | |
bfa30570 | 553 | if (has_constant_operand |
8edeb88b | 554 | || gimple_references_memory_p (stmt)) |
88dbf20f | 555 | return CONSTANT; |
556 | ||
bfa30570 | 557 | return VARYING; |
4ee9c684 | 558 | } |
559 | ||
bfa30570 | 560 | /* Returns true if STMT cannot be constant. */ |
561 | ||
562 | static bool | |
75a70cf9 | 563 | surely_varying_stmt_p (gimple stmt) |
bfa30570 | 564 | { |
565 | /* If the statement has operands that we cannot handle, it cannot be | |
566 | constant. */ | |
75a70cf9 | 567 | if (gimple_has_volatile_ops (stmt)) |
bfa30570 | 568 | return true; |
569 | ||
f257af64 | 570 | /* If it is a call and does not return a value or is not a |
571 | builtin and not an indirect call, it is varying. */ | |
75a70cf9 | 572 | if (is_gimple_call (stmt)) |
f257af64 | 573 | { |
574 | tree fndecl; | |
575 | if (!gimple_call_lhs (stmt) | |
576 | || ((fndecl = gimple_call_fndecl (stmt)) != NULL_TREE | |
5768aeb3 | 577 | && !DECL_BUILT_IN (fndecl))) |
f257af64 | 578 | return true; |
579 | } | |
bfa30570 | 580 | |
8edeb88b | 581 | /* Any other store operation is not interesting. */ |
dd277d48 | 582 | else if (gimple_vdef (stmt)) |
8edeb88b | 583 | return true; |
584 | ||
bfa30570 | 585 | /* Anything other than assignments and conditional jumps are not |
586 | interesting for CCP. */ | |
75a70cf9 | 587 | if (gimple_code (stmt) != GIMPLE_ASSIGN |
f257af64 | 588 | && gimple_code (stmt) != GIMPLE_COND |
589 | && gimple_code (stmt) != GIMPLE_SWITCH | |
590 | && gimple_code (stmt) != GIMPLE_CALL) | |
bfa30570 | 591 | return true; |
592 | ||
593 | return false; | |
594 | } | |
4ee9c684 | 595 | |
41511585 | 596 | /* Initialize local data structures for CCP. */ |
4ee9c684 | 597 | |
598 | static void | |
41511585 | 599 | ccp_initialize (void) |
4ee9c684 | 600 | { |
41511585 | 601 | basic_block bb; |
4ee9c684 | 602 | |
43959b95 | 603 | const_val = XCNEWVEC (prop_value_t, num_ssa_names); |
4ee9c684 | 604 | |
41511585 | 605 | /* Initialize simulation flags for PHI nodes and statements. */ |
606 | FOR_EACH_BB (bb) | |
4ee9c684 | 607 | { |
75a70cf9 | 608 | gimple_stmt_iterator i; |
4ee9c684 | 609 | |
75a70cf9 | 610 | for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) |
41511585 | 611 | { |
75a70cf9 | 612 | gimple stmt = gsi_stmt (i); |
2193544e | 613 | bool is_varying; |
614 | ||
615 | /* If the statement is a control insn, then we do not | |
616 | want to avoid simulating the statement once. Failure | |
617 | to do so means that those edges will never get added. */ | |
618 | if (stmt_ends_bb_p (stmt)) | |
619 | is_varying = false; | |
620 | else | |
621 | is_varying = surely_varying_stmt_p (stmt); | |
4ee9c684 | 622 | |
bfa30570 | 623 | if (is_varying) |
41511585 | 624 | { |
88dbf20f | 625 | tree def; |
626 | ssa_op_iter iter; | |
627 | ||
628 | /* If the statement will not produce a constant, mark | |
629 | all its outputs VARYING. */ | |
630 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) | |
8edeb88b | 631 | set_value_varying (def); |
41511585 | 632 | } |
75a70cf9 | 633 | prop_set_simulate_again (stmt, !is_varying); |
41511585 | 634 | } |
4ee9c684 | 635 | } |
636 | ||
75a70cf9 | 637 | /* Now process PHI nodes. We never clear the simulate_again flag on |
638 | phi nodes, since we do not know which edges are executable yet, | |
639 | except for phi nodes for virtual operands when we do not do store ccp. */ | |
41511585 | 640 | FOR_EACH_BB (bb) |
4ee9c684 | 641 | { |
75a70cf9 | 642 | gimple_stmt_iterator i; |
41511585 | 643 | |
75a70cf9 | 644 | for (i = gsi_start_phis (bb); !gsi_end_p (i); gsi_next (&i)) |
645 | { | |
646 | gimple phi = gsi_stmt (i); | |
647 | ||
61207d43 | 648 | if (!is_gimple_reg (gimple_phi_result (phi))) |
75a70cf9 | 649 | prop_set_simulate_again (phi, false); |
bfa30570 | 650 | else |
75a70cf9 | 651 | prop_set_simulate_again (phi, true); |
41511585 | 652 | } |
4ee9c684 | 653 | } |
41511585 | 654 | } |
4ee9c684 | 655 | |
43fb76c1 | 656 | /* Debug count support. Reset the values of ssa names |
657 | VARYING when the total number ssa names analyzed is | |
658 | beyond the debug count specified. */ | |
659 | ||
660 | static void | |
661 | do_dbg_cnt (void) | |
662 | { | |
663 | unsigned i; | |
664 | for (i = 0; i < num_ssa_names; i++) | |
665 | { | |
666 | if (!dbg_cnt (ccp)) | |
667 | { | |
668 | const_val[i].lattice_val = VARYING; | |
669 | const_val[i].value = NULL_TREE; | |
670 | } | |
671 | } | |
672 | } | |
673 | ||
4ee9c684 | 674 | |
88dbf20f | 675 | /* Do final substitution of propagated values, cleanup the flowgraph and |
48e1416a | 676 | free allocated storage. |
4ee9c684 | 677 | |
33a34f1e | 678 | Return TRUE when something was optimized. */ |
679 | ||
680 | static bool | |
88dbf20f | 681 | ccp_finalize (void) |
4ee9c684 | 682 | { |
43fb76c1 | 683 | bool something_changed; |
684 | ||
685 | do_dbg_cnt (); | |
88dbf20f | 686 | /* Perform substitutions based on the known constant values. */ |
33fd90fa | 687 | something_changed = substitute_and_fold (const_val, ccp_fold_stmt, true); |
4ee9c684 | 688 | |
88dbf20f | 689 | free (const_val); |
e004838d | 690 | const_val = NULL; |
33a34f1e | 691 | return something_changed;; |
4ee9c684 | 692 | } |
693 | ||
694 | ||
88dbf20f | 695 | /* Compute the meet operator between *VAL1 and *VAL2. Store the result |
696 | in VAL1. | |
697 | ||
698 | any M UNDEFINED = any | |
88dbf20f | 699 | any M VARYING = VARYING |
700 | Ci M Cj = Ci if (i == j) | |
701 | Ci M Cj = VARYING if (i != j) | |
bfa30570 | 702 | */ |
4ee9c684 | 703 | |
704 | static void | |
88dbf20f | 705 | ccp_lattice_meet (prop_value_t *val1, prop_value_t *val2) |
4ee9c684 | 706 | { |
88dbf20f | 707 | if (val1->lattice_val == UNDEFINED) |
4ee9c684 | 708 | { |
88dbf20f | 709 | /* UNDEFINED M any = any */ |
710 | *val1 = *val2; | |
41511585 | 711 | } |
88dbf20f | 712 | else if (val2->lattice_val == UNDEFINED) |
92481a4d | 713 | { |
88dbf20f | 714 | /* any M UNDEFINED = any |
715 | Nothing to do. VAL1 already contains the value we want. */ | |
716 | ; | |
92481a4d | 717 | } |
88dbf20f | 718 | else if (val1->lattice_val == VARYING |
719 | || val2->lattice_val == VARYING) | |
41511585 | 720 | { |
88dbf20f | 721 | /* any M VARYING = VARYING. */ |
722 | val1->lattice_val = VARYING; | |
723 | val1->value = NULL_TREE; | |
41511585 | 724 | } |
88dbf20f | 725 | else if (val1->lattice_val == CONSTANT |
726 | && val2->lattice_val == CONSTANT | |
61207d43 | 727 | && simple_cst_equal (val1->value, val2->value) == 1) |
41511585 | 728 | { |
88dbf20f | 729 | /* Ci M Cj = Ci if (i == j) |
730 | Ci M Cj = VARYING if (i != j) | |
731 | ||
732 | If these two values come from memory stores, make sure that | |
7739e598 | 733 | they come from the same memory reference. |
734 | Nothing to do. VAL1 already contains the value we want. */ | |
41511585 | 735 | } |
736 | else | |
737 | { | |
88dbf20f | 738 | /* Any other combination is VARYING. */ |
739 | val1->lattice_val = VARYING; | |
740 | val1->value = NULL_TREE; | |
41511585 | 741 | } |
4ee9c684 | 742 | } |
743 | ||
744 | ||
41511585 | 745 | /* Loop through the PHI_NODE's parameters for BLOCK and compare their |
746 | lattice values to determine PHI_NODE's lattice value. The value of a | |
88dbf20f | 747 | PHI node is determined calling ccp_lattice_meet with all the arguments |
41511585 | 748 | of the PHI node that are incoming via executable edges. */ |
4ee9c684 | 749 | |
41511585 | 750 | static enum ssa_prop_result |
75a70cf9 | 751 | ccp_visit_phi_node (gimple phi) |
4ee9c684 | 752 | { |
75a70cf9 | 753 | unsigned i; |
88dbf20f | 754 | prop_value_t *old_val, new_val; |
4ee9c684 | 755 | |
41511585 | 756 | if (dump_file && (dump_flags & TDF_DETAILS)) |
4ee9c684 | 757 | { |
41511585 | 758 | fprintf (dump_file, "\nVisiting PHI node: "); |
75a70cf9 | 759 | print_gimple_stmt (dump_file, phi, 0, dump_flags); |
4ee9c684 | 760 | } |
4ee9c684 | 761 | |
75a70cf9 | 762 | old_val = get_value (gimple_phi_result (phi)); |
41511585 | 763 | switch (old_val->lattice_val) |
764 | { | |
765 | case VARYING: | |
88dbf20f | 766 | return SSA_PROP_VARYING; |
4ee9c684 | 767 | |
41511585 | 768 | case CONSTANT: |
769 | new_val = *old_val; | |
770 | break; | |
4ee9c684 | 771 | |
41511585 | 772 | case UNDEFINED: |
41511585 | 773 | new_val.lattice_val = UNDEFINED; |
88dbf20f | 774 | new_val.value = NULL_TREE; |
41511585 | 775 | break; |
4ee9c684 | 776 | |
41511585 | 777 | default: |
8c0963c4 | 778 | gcc_unreachable (); |
41511585 | 779 | } |
4ee9c684 | 780 | |
75a70cf9 | 781 | for (i = 0; i < gimple_phi_num_args (phi); i++) |
41511585 | 782 | { |
88dbf20f | 783 | /* Compute the meet operator over all the PHI arguments flowing |
784 | through executable edges. */ | |
75a70cf9 | 785 | edge e = gimple_phi_arg_edge (phi, i); |
4ee9c684 | 786 | |
41511585 | 787 | if (dump_file && (dump_flags & TDF_DETAILS)) |
788 | { | |
789 | fprintf (dump_file, | |
790 | "\n Argument #%d (%d -> %d %sexecutable)\n", | |
791 | i, e->src->index, e->dest->index, | |
792 | (e->flags & EDGE_EXECUTABLE) ? "" : "not "); | |
793 | } | |
794 | ||
795 | /* If the incoming edge is executable, Compute the meet operator for | |
796 | the existing value of the PHI node and the current PHI argument. */ | |
797 | if (e->flags & EDGE_EXECUTABLE) | |
798 | { | |
75a70cf9 | 799 | tree arg = gimple_phi_arg (phi, i)->def; |
88dbf20f | 800 | prop_value_t arg_val; |
4ee9c684 | 801 | |
88dbf20f | 802 | if (is_gimple_min_invariant (arg)) |
41511585 | 803 | { |
88dbf20f | 804 | arg_val.lattice_val = CONSTANT; |
805 | arg_val.value = arg; | |
41511585 | 806 | } |
807 | else | |
bfa30570 | 808 | arg_val = *(get_value (arg)); |
4ee9c684 | 809 | |
88dbf20f | 810 | ccp_lattice_meet (&new_val, &arg_val); |
4ee9c684 | 811 | |
41511585 | 812 | if (dump_file && (dump_flags & TDF_DETAILS)) |
813 | { | |
814 | fprintf (dump_file, "\t"); | |
88dbf20f | 815 | print_generic_expr (dump_file, arg, dump_flags); |
816 | dump_lattice_value (dump_file, "\tValue: ", arg_val); | |
41511585 | 817 | fprintf (dump_file, "\n"); |
818 | } | |
4ee9c684 | 819 | |
41511585 | 820 | if (new_val.lattice_val == VARYING) |
821 | break; | |
822 | } | |
823 | } | |
4ee9c684 | 824 | |
825 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
41511585 | 826 | { |
827 | dump_lattice_value (dump_file, "\n PHI node value: ", new_val); | |
828 | fprintf (dump_file, "\n\n"); | |
829 | } | |
830 | ||
bfa30570 | 831 | /* Make the transition to the new value. */ |
75a70cf9 | 832 | if (set_lattice_value (gimple_phi_result (phi), new_val)) |
41511585 | 833 | { |
834 | if (new_val.lattice_val == VARYING) | |
835 | return SSA_PROP_VARYING; | |
836 | else | |
837 | return SSA_PROP_INTERESTING; | |
838 | } | |
839 | else | |
840 | return SSA_PROP_NOT_INTERESTING; | |
4ee9c684 | 841 | } |
842 | ||
00f4f705 | 843 | /* Get operand number OPNR from the rhs of STMT. Before returning it, |
844 | simplify it to a constant if possible. */ | |
845 | ||
846 | static tree | |
847 | get_rhs_assign_op_for_ccp (gimple stmt, int opnr) | |
848 | { | |
849 | tree op = gimple_op (stmt, opnr); | |
850 | ||
851 | if (TREE_CODE (op) == SSA_NAME) | |
852 | { | |
853 | prop_value_t *val = get_value (op); | |
854 | if (val->lattice_val == CONSTANT) | |
855 | op = get_value (op)->value; | |
856 | } | |
857 | return op; | |
858 | } | |
859 | ||
41511585 | 860 | /* CCP specific front-end to the non-destructive constant folding |
861 | routines. | |
4ee9c684 | 862 | |
863 | Attempt to simplify the RHS of STMT knowing that one or more | |
864 | operands are constants. | |
865 | ||
866 | If simplification is possible, return the simplified RHS, | |
75a70cf9 | 867 | otherwise return the original RHS or NULL_TREE. */ |
4ee9c684 | 868 | |
869 | static tree | |
75a70cf9 | 870 | ccp_fold (gimple stmt) |
4ee9c684 | 871 | { |
389dd41b | 872 | location_t loc = gimple_location (stmt); |
75a70cf9 | 873 | switch (gimple_code (stmt)) |
88dbf20f | 874 | { |
75a70cf9 | 875 | case GIMPLE_ASSIGN: |
876 | { | |
877 | enum tree_code subcode = gimple_assign_rhs_code (stmt); | |
878 | ||
879 | switch (get_gimple_rhs_class (subcode)) | |
880 | { | |
881 | case GIMPLE_SINGLE_RHS: | |
882 | { | |
883 | tree rhs = gimple_assign_rhs1 (stmt); | |
884 | enum tree_code_class kind = TREE_CODE_CLASS (subcode); | |
885 | ||
886 | if (TREE_CODE (rhs) == SSA_NAME) | |
887 | { | |
888 | /* If the RHS is an SSA_NAME, return its known constant value, | |
889 | if any. */ | |
890 | return get_value (rhs)->value; | |
891 | } | |
892 | /* Handle propagating invariant addresses into address operations. | |
893 | The folding we do here matches that in tree-ssa-forwprop.c. */ | |
894 | else if (TREE_CODE (rhs) == ADDR_EXPR) | |
895 | { | |
896 | tree *base; | |
897 | base = &TREE_OPERAND (rhs, 0); | |
898 | while (handled_component_p (*base)) | |
899 | base = &TREE_OPERAND (*base, 0); | |
182cf5a9 | 900 | if (TREE_CODE (*base) == MEM_REF |
75a70cf9 | 901 | && TREE_CODE (TREE_OPERAND (*base, 0)) == SSA_NAME) |
902 | { | |
903 | prop_value_t *val = get_value (TREE_OPERAND (*base, 0)); | |
904 | if (val->lattice_val == CONSTANT | |
182cf5a9 | 905 | && TREE_CODE (val->value) == ADDR_EXPR) |
75a70cf9 | 906 | { |
182cf5a9 | 907 | tree ret, save = *base; |
908 | tree new_base; | |
909 | new_base = fold_build2 (MEM_REF, TREE_TYPE (*base), | |
910 | unshare_expr (val->value), | |
911 | TREE_OPERAND (*base, 1)); | |
75a70cf9 | 912 | /* We need to return a new tree, not modify the IL |
913 | or share parts of it. So play some tricks to | |
914 | avoid manually building it. */ | |
182cf5a9 | 915 | *base = new_base; |
75a70cf9 | 916 | ret = unshare_expr (rhs); |
917 | recompute_tree_invariant_for_addr_expr (ret); | |
918 | *base = save; | |
919 | return ret; | |
920 | } | |
921 | } | |
922 | } | |
388a0bc7 | 923 | else if (TREE_CODE (rhs) == CONSTRUCTOR |
924 | && TREE_CODE (TREE_TYPE (rhs)) == VECTOR_TYPE | |
925 | && (CONSTRUCTOR_NELTS (rhs) | |
926 | == TYPE_VECTOR_SUBPARTS (TREE_TYPE (rhs)))) | |
927 | { | |
928 | unsigned i; | |
929 | tree val, list; | |
930 | ||
931 | list = NULL_TREE; | |
932 | FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (rhs), i, val) | |
933 | { | |
934 | if (TREE_CODE (val) == SSA_NAME | |
935 | && get_value (val)->lattice_val == CONSTANT) | |
936 | val = get_value (val)->value; | |
937 | if (TREE_CODE (val) == INTEGER_CST | |
938 | || TREE_CODE (val) == REAL_CST | |
939 | || TREE_CODE (val) == FIXED_CST) | |
940 | list = tree_cons (NULL_TREE, val, list); | |
941 | else | |
942 | return NULL_TREE; | |
943 | } | |
944 | ||
945 | return build_vector (TREE_TYPE (rhs), nreverse (list)); | |
946 | } | |
4ee9c684 | 947 | |
75a70cf9 | 948 | if (kind == tcc_reference) |
3e4be816 | 949 | { |
0fefde02 | 950 | if ((TREE_CODE (rhs) == VIEW_CONVERT_EXPR |
951 | || TREE_CODE (rhs) == REALPART_EXPR | |
952 | || TREE_CODE (rhs) == IMAGPART_EXPR) | |
3e4be816 | 953 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME) |
954 | { | |
955 | prop_value_t *val = get_value (TREE_OPERAND (rhs, 0)); | |
956 | if (val->lattice_val == CONSTANT) | |
389dd41b | 957 | return fold_unary_loc (EXPR_LOCATION (rhs), |
958 | TREE_CODE (rhs), | |
3e4be816 | 959 | TREE_TYPE (rhs), val->value); |
960 | } | |
182cf5a9 | 961 | else if (TREE_CODE (rhs) == MEM_REF |
8edeb88b | 962 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME) |
963 | { | |
964 | prop_value_t *val = get_value (TREE_OPERAND (rhs, 0)); | |
965 | if (val->lattice_val == CONSTANT | |
182cf5a9 | 966 | && TREE_CODE (val->value) == ADDR_EXPR) |
967 | { | |
968 | tree tem = fold_build2 (MEM_REF, TREE_TYPE (rhs), | |
969 | unshare_expr (val->value), | |
970 | TREE_OPERAND (rhs, 1)); | |
971 | if (tem) | |
972 | rhs = tem; | |
973 | } | |
8edeb88b | 974 | } |
3e4be816 | 975 | return fold_const_aggregate_ref (rhs); |
976 | } | |
75a70cf9 | 977 | else if (kind == tcc_declaration) |
978 | return get_symbol_constant_value (rhs); | |
979 | return rhs; | |
980 | } | |
48e1416a | 981 | |
75a70cf9 | 982 | case GIMPLE_UNARY_RHS: |
983 | { | |
984 | /* Handle unary operators that can appear in GIMPLE form. | |
985 | Note that we know the single operand must be a constant, | |
986 | so this should almost always return a simplified RHS. */ | |
987 | tree lhs = gimple_assign_lhs (stmt); | |
00f4f705 | 988 | tree op0 = get_rhs_assign_op_for_ccp (stmt, 1); |
75a70cf9 | 989 | |
990 | /* Conversions are useless for CCP purposes if they are | |
991 | value-preserving. Thus the restrictions that | |
992 | useless_type_conversion_p places for pointer type conversions | |
993 | do not apply here. Substitution later will only substitute to | |
994 | allowed places. */ | |
d9659041 | 995 | if (CONVERT_EXPR_CODE_P (subcode) |
5768aeb3 | 996 | && POINTER_TYPE_P (TREE_TYPE (lhs)) |
182cf5a9 | 997 | && POINTER_TYPE_P (TREE_TYPE (op0))) |
5768aeb3 | 998 | { |
999 | tree tem; | |
182cf5a9 | 1000 | /* Try to re-construct array references on-the-fly. */ |
5768aeb3 | 1001 | if (!useless_type_conversion_p (TREE_TYPE (lhs), |
1002 | TREE_TYPE (op0)) | |
1003 | && ((tem = maybe_fold_offset_to_address | |
389dd41b | 1004 | (loc, |
e60a6f7b | 1005 | op0, integer_zero_node, TREE_TYPE (lhs))) |
5768aeb3 | 1006 | != NULL_TREE)) |
1007 | return tem; | |
1008 | return op0; | |
1009 | } | |
75a70cf9 | 1010 | |
48e1416a | 1011 | return |
389dd41b | 1012 | fold_unary_ignore_overflow_loc (loc, subcode, |
1013 | gimple_expr_type (stmt), op0); | |
f1fb2997 | 1014 | } |
75a70cf9 | 1015 | |
1016 | case GIMPLE_BINARY_RHS: | |
1017 | { | |
1018 | /* Handle binary operators that can appear in GIMPLE form. */ | |
00f4f705 | 1019 | tree op0 = get_rhs_assign_op_for_ccp (stmt, 1); |
1020 | tree op1 = get_rhs_assign_op_for_ccp (stmt, 2); | |
75a70cf9 | 1021 | |
182cf5a9 | 1022 | /* Translate &x + CST into an invariant form suitable for |
1023 | further propagation. */ | |
5768aeb3 | 1024 | if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR |
1025 | && TREE_CODE (op0) == ADDR_EXPR | |
1026 | && TREE_CODE (op1) == INTEGER_CST) | |
1027 | { | |
182cf5a9 | 1028 | tree off = fold_convert (ptr_type_node, op1); |
1029 | return build_fold_addr_expr | |
1030 | (fold_build2 (MEM_REF, | |
1031 | TREE_TYPE (TREE_TYPE (op0)), | |
1032 | unshare_expr (op0), off)); | |
5768aeb3 | 1033 | } |
1034 | ||
389dd41b | 1035 | return fold_binary_loc (loc, subcode, |
182cf5a9 | 1036 | gimple_expr_type (stmt), op0, op1); |
75a70cf9 | 1037 | } |
1038 | ||
00f4f705 | 1039 | case GIMPLE_TERNARY_RHS: |
1040 | { | |
1041 | /* Handle binary operators that can appear in GIMPLE form. */ | |
1042 | tree op0 = get_rhs_assign_op_for_ccp (stmt, 1); | |
1043 | tree op1 = get_rhs_assign_op_for_ccp (stmt, 2); | |
1044 | tree op2 = get_rhs_assign_op_for_ccp (stmt, 3); | |
1045 | ||
1046 | return fold_ternary_loc (loc, subcode, | |
1047 | gimple_expr_type (stmt), op0, op1, op2); | |
1048 | } | |
1049 | ||
75a70cf9 | 1050 | default: |
1051 | gcc_unreachable (); | |
1052 | } | |
1053 | } | |
1054 | break; | |
4ee9c684 | 1055 | |
75a70cf9 | 1056 | case GIMPLE_CALL: |
f257af64 | 1057 | { |
1058 | tree fn = gimple_call_fn (stmt); | |
1059 | prop_value_t *val; | |
1060 | ||
1061 | if (TREE_CODE (fn) == SSA_NAME) | |
1062 | { | |
1063 | val = get_value (fn); | |
1064 | if (val->lattice_val == CONSTANT) | |
1065 | fn = val->value; | |
1066 | } | |
1067 | if (TREE_CODE (fn) == ADDR_EXPR | |
8ef4f124 | 1068 | && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL |
f257af64 | 1069 | && DECL_BUILT_IN (TREE_OPERAND (fn, 0))) |
1070 | { | |
1071 | tree *args = XALLOCAVEC (tree, gimple_call_num_args (stmt)); | |
1072 | tree call, retval; | |
1073 | unsigned i; | |
1074 | for (i = 0; i < gimple_call_num_args (stmt); ++i) | |
1075 | { | |
1076 | args[i] = gimple_call_arg (stmt, i); | |
1077 | if (TREE_CODE (args[i]) == SSA_NAME) | |
1078 | { | |
1079 | val = get_value (args[i]); | |
1080 | if (val->lattice_val == CONSTANT) | |
1081 | args[i] = val->value; | |
1082 | } | |
1083 | } | |
389dd41b | 1084 | call = build_call_array_loc (loc, |
1085 | gimple_call_return_type (stmt), | |
1086 | fn, gimple_call_num_args (stmt), args); | |
1087 | retval = fold_call_expr (EXPR_LOCATION (call), call, false); | |
f257af64 | 1088 | if (retval) |
1089 | /* fold_call_expr wraps the result inside a NOP_EXPR. */ | |
1090 | STRIP_NOPS (retval); | |
1091 | return retval; | |
1092 | } | |
1093 | return NULL_TREE; | |
1094 | } | |
4ee9c684 | 1095 | |
75a70cf9 | 1096 | case GIMPLE_COND: |
1097 | { | |
1098 | /* Handle comparison operators that can appear in GIMPLE form. */ | |
1099 | tree op0 = gimple_cond_lhs (stmt); | |
1100 | tree op1 = gimple_cond_rhs (stmt); | |
1101 | enum tree_code code = gimple_cond_code (stmt); | |
1102 | ||
1103 | /* Simplify the operands down to constants when appropriate. */ | |
1104 | if (TREE_CODE (op0) == SSA_NAME) | |
1105 | { | |
1106 | prop_value_t *val = get_value (op0); | |
1107 | if (val->lattice_val == CONSTANT) | |
1108 | op0 = val->value; | |
1109 | } | |
1110 | ||
1111 | if (TREE_CODE (op1) == SSA_NAME) | |
1112 | { | |
1113 | prop_value_t *val = get_value (op1); | |
1114 | if (val->lattice_val == CONSTANT) | |
1115 | op1 = val->value; | |
1116 | } | |
1117 | ||
389dd41b | 1118 | return fold_binary_loc (loc, code, boolean_type_node, op0, op1); |
75a70cf9 | 1119 | } |
4ee9c684 | 1120 | |
75a70cf9 | 1121 | case GIMPLE_SWITCH: |
1122 | { | |
1123 | tree rhs = gimple_switch_index (stmt); | |
04236c3a | 1124 | |
75a70cf9 | 1125 | if (TREE_CODE (rhs) == SSA_NAME) |
1126 | { | |
1127 | /* If the RHS is an SSA_NAME, return its known constant value, | |
1128 | if any. */ | |
1129 | return get_value (rhs)->value; | |
1130 | } | |
04236c3a | 1131 | |
75a70cf9 | 1132 | return rhs; |
1133 | } | |
912f109f | 1134 | |
75a70cf9 | 1135 | default: |
1136 | gcc_unreachable (); | |
4ee9c684 | 1137 | } |
4ee9c684 | 1138 | } |
1139 | ||
1140 | ||
8782adcf | 1141 | /* Return the tree representing the element referenced by T if T is an |
1142 | ARRAY_REF or COMPONENT_REF into constant aggregates. Return | |
1143 | NULL_TREE otherwise. */ | |
1144 | ||
e004838d | 1145 | tree |
8782adcf | 1146 | fold_const_aggregate_ref (tree t) |
1147 | { | |
1148 | prop_value_t *value; | |
c75b4594 | 1149 | tree base, ctor, idx, field; |
1150 | unsigned HOST_WIDE_INT cnt; | |
1151 | tree cfield, cval; | |
8782adcf | 1152 | |
8edeb88b | 1153 | if (TREE_CODE_CLASS (TREE_CODE (t)) == tcc_declaration) |
1154 | return get_symbol_constant_value (t); | |
1155 | ||
8782adcf | 1156 | switch (TREE_CODE (t)) |
1157 | { | |
1158 | case ARRAY_REF: | |
1159 | /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its | |
1160 | DECL_INITIAL. If BASE is a nested reference into another | |
1161 | ARRAY_REF or COMPONENT_REF, make a recursive call to resolve | |
1162 | the inner reference. */ | |
1163 | base = TREE_OPERAND (t, 0); | |
1164 | switch (TREE_CODE (base)) | |
1165 | { | |
1c196c04 | 1166 | case MEM_REF: |
1167 | /* ??? We could handle this case. */ | |
1168 | if (!integer_zerop (TREE_OPERAND (base, 1))) | |
1169 | return NULL_TREE; | |
1170 | base = get_base_address (base); | |
1171 | if (!base | |
1172 | || TREE_CODE (base) != VAR_DECL) | |
1173 | return NULL_TREE; | |
1174 | ||
1175 | /* Fallthru. */ | |
8782adcf | 1176 | case VAR_DECL: |
1177 | if (!TREE_READONLY (base) | |
1178 | || TREE_CODE (TREE_TYPE (base)) != ARRAY_TYPE | |
1179 | || !targetm.binds_local_p (base)) | |
1180 | return NULL_TREE; | |
1181 | ||
1182 | ctor = DECL_INITIAL (base); | |
1183 | break; | |
1184 | ||
1185 | case ARRAY_REF: | |
1186 | case COMPONENT_REF: | |
1187 | ctor = fold_const_aggregate_ref (base); | |
1188 | break; | |
1189 | ||
04236c3a | 1190 | case STRING_CST: |
1191 | case CONSTRUCTOR: | |
1192 | ctor = base; | |
1193 | break; | |
1194 | ||
8782adcf | 1195 | default: |
1196 | return NULL_TREE; | |
1197 | } | |
1198 | ||
1199 | if (ctor == NULL_TREE | |
4f61cce6 | 1200 | || (TREE_CODE (ctor) != CONSTRUCTOR |
1201 | && TREE_CODE (ctor) != STRING_CST) | |
8782adcf | 1202 | || !TREE_STATIC (ctor)) |
1203 | return NULL_TREE; | |
1204 | ||
1205 | /* Get the index. If we have an SSA_NAME, try to resolve it | |
1206 | with the current lattice value for the SSA_NAME. */ | |
1207 | idx = TREE_OPERAND (t, 1); | |
1208 | switch (TREE_CODE (idx)) | |
1209 | { | |
1210 | case SSA_NAME: | |
bfa30570 | 1211 | if ((value = get_value (idx)) |
8782adcf | 1212 | && value->lattice_val == CONSTANT |
1213 | && TREE_CODE (value->value) == INTEGER_CST) | |
1214 | idx = value->value; | |
1215 | else | |
1216 | return NULL_TREE; | |
1217 | break; | |
1218 | ||
1219 | case INTEGER_CST: | |
1220 | break; | |
1221 | ||
1222 | default: | |
1223 | return NULL_TREE; | |
1224 | } | |
1225 | ||
4f61cce6 | 1226 | /* Fold read from constant string. */ |
1227 | if (TREE_CODE (ctor) == STRING_CST) | |
1228 | { | |
1229 | if ((TYPE_MODE (TREE_TYPE (t)) | |
1230 | == TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1231 | && (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1232 | == MODE_INT) | |
1233 | && GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) == 1 | |
1234 | && compare_tree_int (idx, TREE_STRING_LENGTH (ctor)) < 0) | |
7b050b7b | 1235 | return build_int_cst_type (TREE_TYPE (t), |
1236 | (TREE_STRING_POINTER (ctor) | |
1237 | [TREE_INT_CST_LOW (idx)])); | |
4f61cce6 | 1238 | return NULL_TREE; |
1239 | } | |
1240 | ||
8782adcf | 1241 | /* Whoo-hoo! I'll fold ya baby. Yeah! */ |
c75b4594 | 1242 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) |
1243 | if (tree_int_cst_equal (cfield, idx)) | |
590d65aa | 1244 | { |
6872bf3c | 1245 | STRIP_NOPS (cval); |
3a44a278 | 1246 | if (TREE_CODE (cval) == ADDR_EXPR) |
1247 | { | |
1248 | tree base = get_base_address (TREE_OPERAND (cval, 0)); | |
1249 | if (base && TREE_CODE (base) == VAR_DECL) | |
1250 | add_referenced_var (base); | |
1251 | } | |
590d65aa | 1252 | return cval; |
1253 | } | |
8782adcf | 1254 | break; |
1255 | ||
1256 | case COMPONENT_REF: | |
1257 | /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its | |
1258 | DECL_INITIAL. If BASE is a nested reference into another | |
1259 | ARRAY_REF or COMPONENT_REF, make a recursive call to resolve | |
1260 | the inner reference. */ | |
1261 | base = TREE_OPERAND (t, 0); | |
1262 | switch (TREE_CODE (base)) | |
1263 | { | |
1264 | case VAR_DECL: | |
1265 | if (!TREE_READONLY (base) | |
1266 | || TREE_CODE (TREE_TYPE (base)) != RECORD_TYPE | |
1267 | || !targetm.binds_local_p (base)) | |
1268 | return NULL_TREE; | |
1269 | ||
1270 | ctor = DECL_INITIAL (base); | |
1271 | break; | |
1272 | ||
1273 | case ARRAY_REF: | |
1274 | case COMPONENT_REF: | |
1275 | ctor = fold_const_aggregate_ref (base); | |
1276 | break; | |
1277 | ||
1278 | default: | |
1279 | return NULL_TREE; | |
1280 | } | |
1281 | ||
1282 | if (ctor == NULL_TREE | |
1283 | || TREE_CODE (ctor) != CONSTRUCTOR | |
1284 | || !TREE_STATIC (ctor)) | |
1285 | return NULL_TREE; | |
1286 | ||
1287 | field = TREE_OPERAND (t, 1); | |
1288 | ||
c75b4594 | 1289 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) |
1290 | if (cfield == field | |
8782adcf | 1291 | /* FIXME: Handle bit-fields. */ |
c75b4594 | 1292 | && ! DECL_BIT_FIELD (cfield)) |
590d65aa | 1293 | { |
6872bf3c | 1294 | STRIP_NOPS (cval); |
3a44a278 | 1295 | if (TREE_CODE (cval) == ADDR_EXPR) |
1296 | { | |
1297 | tree base = get_base_address (TREE_OPERAND (cval, 0)); | |
1298 | if (base && TREE_CODE (base) == VAR_DECL) | |
1299 | add_referenced_var (base); | |
1300 | } | |
590d65aa | 1301 | return cval; |
1302 | } | |
8782adcf | 1303 | break; |
1304 | ||
908cb59d | 1305 | case REALPART_EXPR: |
1306 | case IMAGPART_EXPR: | |
1307 | { | |
1308 | tree c = fold_const_aggregate_ref (TREE_OPERAND (t, 0)); | |
1309 | if (c && TREE_CODE (c) == COMPLEX_CST) | |
389dd41b | 1310 | return fold_build1_loc (EXPR_LOCATION (t), |
1311 | TREE_CODE (t), TREE_TYPE (t), c); | |
908cb59d | 1312 | break; |
1313 | } | |
04236c3a | 1314 | |
182cf5a9 | 1315 | case MEM_REF: |
1316 | /* Get the base object we are accessing. */ | |
1317 | base = TREE_OPERAND (t, 0); | |
1318 | if (TREE_CODE (base) == SSA_NAME | |
1319 | && (value = get_value (base)) | |
1320 | && value->lattice_val == CONSTANT) | |
1321 | base = value->value; | |
1322 | if (TREE_CODE (base) != ADDR_EXPR) | |
1323 | return NULL_TREE; | |
1324 | base = TREE_OPERAND (base, 0); | |
1325 | switch (TREE_CODE (base)) | |
1326 | { | |
1327 | case VAR_DECL: | |
1328 | if (DECL_P (base) | |
1329 | && !AGGREGATE_TYPE_P (TREE_TYPE (base)) | |
1330 | && integer_zerop (TREE_OPERAND (t, 1))) | |
dbeb5fe0 | 1331 | { |
1332 | tree res = get_symbol_constant_value (base); | |
1333 | if (res | |
1334 | && !useless_type_conversion_p | |
1335 | (TREE_TYPE (t), TREE_TYPE (res))) | |
1336 | res = fold_unary (VIEW_CONVERT_EXPR, TREE_TYPE (t), res); | |
1337 | return res; | |
1338 | } | |
182cf5a9 | 1339 | |
1340 | if (!TREE_READONLY (base) | |
1341 | || TREE_CODE (TREE_TYPE (base)) != ARRAY_TYPE | |
1342 | || !targetm.binds_local_p (base)) | |
1343 | return NULL_TREE; | |
1344 | ||
1345 | ctor = DECL_INITIAL (base); | |
1346 | break; | |
1347 | ||
1348 | case STRING_CST: | |
1349 | case CONSTRUCTOR: | |
1350 | ctor = base; | |
1351 | break; | |
1352 | ||
1353 | default: | |
1354 | return NULL_TREE; | |
1355 | } | |
1356 | ||
1357 | if (ctor == NULL_TREE | |
1358 | || (TREE_CODE (ctor) != CONSTRUCTOR | |
1359 | && TREE_CODE (ctor) != STRING_CST) | |
1360 | || !TREE_STATIC (ctor)) | |
1361 | return NULL_TREE; | |
1362 | ||
1363 | /* Get the byte offset. */ | |
1364 | idx = TREE_OPERAND (t, 1); | |
1365 | ||
1366 | /* Fold read from constant string. */ | |
1367 | if (TREE_CODE (ctor) == STRING_CST) | |
1368 | { | |
1369 | if ((TYPE_MODE (TREE_TYPE (t)) | |
1370 | == TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1371 | && (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1372 | == MODE_INT) | |
1373 | && GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) == 1 | |
1374 | && compare_tree_int (idx, TREE_STRING_LENGTH (ctor)) < 0) | |
1375 | return build_int_cst_type (TREE_TYPE (t), | |
1376 | (TREE_STRING_POINTER (ctor) | |
1377 | [TREE_INT_CST_LOW (idx)])); | |
1378 | return NULL_TREE; | |
1379 | } | |
1380 | ||
1381 | /* ??? Implement byte-offset indexing into a non-array CONSTRUCTOR. */ | |
1382 | if (TREE_CODE (TREE_TYPE (ctor)) == ARRAY_TYPE | |
1383 | && (TYPE_MODE (TREE_TYPE (t)) | |
1384 | == TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1385 | && GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (t))) != 0 | |
1386 | && integer_zerop | |
1387 | (int_const_binop | |
1388 | (TRUNC_MOD_EXPR, idx, | |
1389 | size_int (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (t)))), 0))) | |
1390 | { | |
1391 | idx = int_const_binop (TRUNC_DIV_EXPR, idx, | |
1392 | size_int (GET_MODE_SIZE | |
1393 | (TYPE_MODE (TREE_TYPE (t)))), 0); | |
1394 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) | |
1395 | if (tree_int_cst_equal (cfield, idx)) | |
1396 | { | |
1397 | STRIP_NOPS (cval); | |
1398 | if (TREE_CODE (cval) == ADDR_EXPR) | |
1399 | { | |
1400 | tree base = get_base_address (TREE_OPERAND (cval, 0)); | |
1401 | if (base && TREE_CODE (base) == VAR_DECL) | |
1402 | add_referenced_var (base); | |
1403 | } | |
1404 | if (useless_type_conversion_p (TREE_TYPE (t), TREE_TYPE (cval))) | |
1405 | return cval; | |
1406 | else if (CONSTANT_CLASS_P (cval)) | |
1407 | return fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (t), cval); | |
1408 | else | |
1409 | return NULL_TREE; | |
1410 | } | |
1411 | } | |
1412 | break; | |
04236c3a | 1413 | |
8782adcf | 1414 | default: |
1415 | break; | |
1416 | } | |
1417 | ||
1418 | return NULL_TREE; | |
1419 | } | |
75a70cf9 | 1420 | |
1421 | /* Evaluate statement STMT. | |
1422 | Valid only for assignments, calls, conditionals, and switches. */ | |
4ee9c684 | 1423 | |
88dbf20f | 1424 | static prop_value_t |
75a70cf9 | 1425 | evaluate_stmt (gimple stmt) |
4ee9c684 | 1426 | { |
88dbf20f | 1427 | prop_value_t val; |
4f61cce6 | 1428 | tree simplified = NULL_TREE; |
88dbf20f | 1429 | ccp_lattice_t likelyvalue = likely_value (stmt); |
add6ee5e | 1430 | bool is_constant; |
88dbf20f | 1431 | |
add6ee5e | 1432 | fold_defer_overflow_warnings (); |
1433 | ||
4ee9c684 | 1434 | /* If the statement is likely to have a CONSTANT result, then try |
1435 | to fold the statement to determine the constant value. */ | |
75a70cf9 | 1436 | /* FIXME. This is the only place that we call ccp_fold. |
1437 | Since likely_value never returns CONSTANT for calls, we will | |
1438 | not attempt to fold them, including builtins that may profit. */ | |
4ee9c684 | 1439 | if (likelyvalue == CONSTANT) |
1440 | simplified = ccp_fold (stmt); | |
1441 | /* If the statement is likely to have a VARYING result, then do not | |
1442 | bother folding the statement. */ | |
04236c3a | 1443 | else if (likelyvalue == VARYING) |
75a70cf9 | 1444 | { |
590c3166 | 1445 | enum gimple_code code = gimple_code (stmt); |
75a70cf9 | 1446 | if (code == GIMPLE_ASSIGN) |
1447 | { | |
1448 | enum tree_code subcode = gimple_assign_rhs_code (stmt); | |
48e1416a | 1449 | |
75a70cf9 | 1450 | /* Other cases cannot satisfy is_gimple_min_invariant |
1451 | without folding. */ | |
1452 | if (get_gimple_rhs_class (subcode) == GIMPLE_SINGLE_RHS) | |
1453 | simplified = gimple_assign_rhs1 (stmt); | |
1454 | } | |
1455 | else if (code == GIMPLE_SWITCH) | |
1456 | simplified = gimple_switch_index (stmt); | |
1457 | else | |
a65c4d64 | 1458 | /* These cannot satisfy is_gimple_min_invariant without folding. */ |
1459 | gcc_assert (code == GIMPLE_CALL || code == GIMPLE_COND); | |
75a70cf9 | 1460 | } |
4ee9c684 | 1461 | |
add6ee5e | 1462 | is_constant = simplified && is_gimple_min_invariant (simplified); |
1463 | ||
1464 | fold_undefer_overflow_warnings (is_constant, stmt, 0); | |
1465 | ||
912f109f | 1466 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1467 | { | |
1468 | fprintf (dump_file, "which is likely "); | |
1469 | switch (likelyvalue) | |
1470 | { | |
1471 | case CONSTANT: | |
1472 | fprintf (dump_file, "CONSTANT"); | |
1473 | break; | |
1474 | case UNDEFINED: | |
1475 | fprintf (dump_file, "UNDEFINED"); | |
1476 | break; | |
1477 | case VARYING: | |
1478 | fprintf (dump_file, "VARYING"); | |
1479 | break; | |
1480 | default:; | |
1481 | } | |
1482 | fprintf (dump_file, "\n"); | |
1483 | } | |
1484 | ||
add6ee5e | 1485 | if (is_constant) |
4ee9c684 | 1486 | { |
1487 | /* The statement produced a constant value. */ | |
1488 | val.lattice_val = CONSTANT; | |
88dbf20f | 1489 | val.value = simplified; |
4ee9c684 | 1490 | } |
1491 | else | |
1492 | { | |
1493 | /* The statement produced a nonconstant value. If the statement | |
88dbf20f | 1494 | had UNDEFINED operands, then the result of the statement |
1495 | should be UNDEFINED. Otherwise, the statement is VARYING. */ | |
bfa30570 | 1496 | if (likelyvalue == UNDEFINED) |
b765fa12 | 1497 | val.lattice_val = likelyvalue; |
1498 | else | |
1499 | val.lattice_val = VARYING; | |
1500 | ||
88dbf20f | 1501 | val.value = NULL_TREE; |
4ee9c684 | 1502 | } |
41511585 | 1503 | |
1504 | return val; | |
4ee9c684 | 1505 | } |
1506 | ||
6688f8ec | 1507 | /* Fold the stmt at *GSI with CCP specific information that propagating |
1508 | and regular folding does not catch. */ | |
1509 | ||
1510 | static bool | |
1511 | ccp_fold_stmt (gimple_stmt_iterator *gsi) | |
1512 | { | |
1513 | gimple stmt = gsi_stmt (*gsi); | |
6688f8ec | 1514 | |
94144e68 | 1515 | switch (gimple_code (stmt)) |
1516 | { | |
1517 | case GIMPLE_COND: | |
1518 | { | |
1519 | prop_value_t val; | |
1520 | /* Statement evaluation will handle type mismatches in constants | |
1521 | more gracefully than the final propagation. This allows us to | |
1522 | fold more conditionals here. */ | |
1523 | val = evaluate_stmt (stmt); | |
1524 | if (val.lattice_val != CONSTANT | |
1525 | || TREE_CODE (val.value) != INTEGER_CST) | |
1526 | return false; | |
1527 | ||
1528 | if (integer_zerop (val.value)) | |
1529 | gimple_cond_make_false (stmt); | |
1530 | else | |
1531 | gimple_cond_make_true (stmt); | |
6688f8ec | 1532 | |
94144e68 | 1533 | return true; |
1534 | } | |
6688f8ec | 1535 | |
94144e68 | 1536 | case GIMPLE_CALL: |
1537 | { | |
1538 | tree lhs = gimple_call_lhs (stmt); | |
1539 | prop_value_t *val; | |
1540 | tree argt; | |
1541 | bool changed = false; | |
1542 | unsigned i; | |
1543 | ||
1544 | /* If the call was folded into a constant make sure it goes | |
1545 | away even if we cannot propagate into all uses because of | |
1546 | type issues. */ | |
1547 | if (lhs | |
1548 | && TREE_CODE (lhs) == SSA_NAME | |
1549 | && (val = get_value (lhs)) | |
1550 | && val->lattice_val == CONSTANT) | |
1551 | { | |
338cce8f | 1552 | tree new_rhs = unshare_expr (val->value); |
1553 | bool res; | |
94144e68 | 1554 | if (!useless_type_conversion_p (TREE_TYPE (lhs), |
1555 | TREE_TYPE (new_rhs))) | |
1556 | new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs); | |
338cce8f | 1557 | res = update_call_from_tree (gsi, new_rhs); |
1558 | gcc_assert (res); | |
94144e68 | 1559 | return true; |
1560 | } | |
1561 | ||
1562 | /* Propagate into the call arguments. Compared to replace_uses_in | |
1563 | this can use the argument slot types for type verification | |
1564 | instead of the current argument type. We also can safely | |
1565 | drop qualifiers here as we are dealing with constants anyway. */ | |
1566 | argt = TYPE_ARG_TYPES (TREE_TYPE (TREE_TYPE (gimple_call_fn (stmt)))); | |
1567 | for (i = 0; i < gimple_call_num_args (stmt) && argt; | |
1568 | ++i, argt = TREE_CHAIN (argt)) | |
1569 | { | |
1570 | tree arg = gimple_call_arg (stmt, i); | |
1571 | if (TREE_CODE (arg) == SSA_NAME | |
1572 | && (val = get_value (arg)) | |
1573 | && val->lattice_val == CONSTANT | |
1574 | && useless_type_conversion_p | |
1575 | (TYPE_MAIN_VARIANT (TREE_VALUE (argt)), | |
1576 | TYPE_MAIN_VARIANT (TREE_TYPE (val->value)))) | |
1577 | { | |
338cce8f | 1578 | gimple_call_set_arg (stmt, i, unshare_expr (val->value)); |
94144e68 | 1579 | changed = true; |
1580 | } | |
1581 | } | |
1582 | ||
1583 | return changed; | |
1584 | } | |
6688f8ec | 1585 | |
6872bf3c | 1586 | case GIMPLE_ASSIGN: |
1587 | { | |
1588 | tree lhs = gimple_assign_lhs (stmt); | |
1589 | prop_value_t *val; | |
1590 | ||
1591 | /* If we have a load that turned out to be constant replace it | |
1592 | as we cannot propagate into all uses in all cases. */ | |
1593 | if (gimple_assign_single_p (stmt) | |
1594 | && TREE_CODE (lhs) == SSA_NAME | |
1595 | && (val = get_value (lhs)) | |
1596 | && val->lattice_val == CONSTANT) | |
1597 | { | |
1598 | tree rhs = unshare_expr (val->value); | |
1599 | if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs))) | |
182cf5a9 | 1600 | rhs = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), rhs); |
6872bf3c | 1601 | gimple_assign_set_rhs_from_tree (gsi, rhs); |
1602 | return true; | |
1603 | } | |
1604 | ||
1605 | return false; | |
1606 | } | |
1607 | ||
94144e68 | 1608 | default: |
1609 | return false; | |
1610 | } | |
6688f8ec | 1611 | } |
1612 | ||
41511585 | 1613 | /* Visit the assignment statement STMT. Set the value of its LHS to the |
88dbf20f | 1614 | value computed by the RHS and store LHS in *OUTPUT_P. If STMT |
1615 | creates virtual definitions, set the value of each new name to that | |
75a70cf9 | 1616 | of the RHS (if we can derive a constant out of the RHS). |
1617 | Value-returning call statements also perform an assignment, and | |
1618 | are handled here. */ | |
4ee9c684 | 1619 | |
41511585 | 1620 | static enum ssa_prop_result |
75a70cf9 | 1621 | visit_assignment (gimple stmt, tree *output_p) |
4ee9c684 | 1622 | { |
88dbf20f | 1623 | prop_value_t val; |
88dbf20f | 1624 | enum ssa_prop_result retval; |
4ee9c684 | 1625 | |
75a70cf9 | 1626 | tree lhs = gimple_get_lhs (stmt); |
4ee9c684 | 1627 | |
75a70cf9 | 1628 | gcc_assert (gimple_code (stmt) != GIMPLE_CALL |
1629 | || gimple_call_lhs (stmt) != NULL_TREE); | |
1630 | ||
1631 | if (gimple_assign_copy_p (stmt)) | |
41511585 | 1632 | { |
75a70cf9 | 1633 | tree rhs = gimple_assign_rhs1 (stmt); |
88dbf20f | 1634 | |
75a70cf9 | 1635 | if (TREE_CODE (rhs) == SSA_NAME) |
1636 | { | |
1637 | /* For a simple copy operation, we copy the lattice values. */ | |
1638 | prop_value_t *nval = get_value (rhs); | |
1639 | val = *nval; | |
1640 | } | |
88dbf20f | 1641 | else |
75a70cf9 | 1642 | val = evaluate_stmt (stmt); |
41511585 | 1643 | } |
1644 | else | |
75a70cf9 | 1645 | /* Evaluate the statement, which could be |
1646 | either a GIMPLE_ASSIGN or a GIMPLE_CALL. */ | |
04236c3a | 1647 | val = evaluate_stmt (stmt); |
4ee9c684 | 1648 | |
88dbf20f | 1649 | retval = SSA_PROP_NOT_INTERESTING; |
4ee9c684 | 1650 | |
41511585 | 1651 | /* Set the lattice value of the statement's output. */ |
88dbf20f | 1652 | if (TREE_CODE (lhs) == SSA_NAME) |
4ee9c684 | 1653 | { |
88dbf20f | 1654 | /* If STMT is an assignment to an SSA_NAME, we only have one |
1655 | value to set. */ | |
1656 | if (set_lattice_value (lhs, val)) | |
1657 | { | |
1658 | *output_p = lhs; | |
1659 | if (val.lattice_val == VARYING) | |
1660 | retval = SSA_PROP_VARYING; | |
1661 | else | |
1662 | retval = SSA_PROP_INTERESTING; | |
1663 | } | |
4ee9c684 | 1664 | } |
88dbf20f | 1665 | |
1666 | return retval; | |
4ee9c684 | 1667 | } |
1668 | ||
4ee9c684 | 1669 | |
41511585 | 1670 | /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING |
1671 | if it can determine which edge will be taken. Otherwise, return | |
1672 | SSA_PROP_VARYING. */ | |
1673 | ||
1674 | static enum ssa_prop_result | |
75a70cf9 | 1675 | visit_cond_stmt (gimple stmt, edge *taken_edge_p) |
4ee9c684 | 1676 | { |
88dbf20f | 1677 | prop_value_t val; |
41511585 | 1678 | basic_block block; |
1679 | ||
75a70cf9 | 1680 | block = gimple_bb (stmt); |
41511585 | 1681 | val = evaluate_stmt (stmt); |
1682 | ||
1683 | /* Find which edge out of the conditional block will be taken and add it | |
1684 | to the worklist. If no single edge can be determined statically, | |
1685 | return SSA_PROP_VARYING to feed all the outgoing edges to the | |
1686 | propagation engine. */ | |
88dbf20f | 1687 | *taken_edge_p = val.value ? find_taken_edge (block, val.value) : 0; |
41511585 | 1688 | if (*taken_edge_p) |
1689 | return SSA_PROP_INTERESTING; | |
1690 | else | |
1691 | return SSA_PROP_VARYING; | |
4ee9c684 | 1692 | } |
1693 | ||
4ee9c684 | 1694 | |
41511585 | 1695 | /* Evaluate statement STMT. If the statement produces an output value and |
1696 | its evaluation changes the lattice value of its output, return | |
1697 | SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the | |
1698 | output value. | |
48e1416a | 1699 | |
41511585 | 1700 | If STMT is a conditional branch and we can determine its truth |
1701 | value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying | |
1702 | value, return SSA_PROP_VARYING. */ | |
4ee9c684 | 1703 | |
41511585 | 1704 | static enum ssa_prop_result |
75a70cf9 | 1705 | ccp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p) |
41511585 | 1706 | { |
41511585 | 1707 | tree def; |
1708 | ssa_op_iter iter; | |
4ee9c684 | 1709 | |
41511585 | 1710 | if (dump_file && (dump_flags & TDF_DETAILS)) |
4ee9c684 | 1711 | { |
88dbf20f | 1712 | fprintf (dump_file, "\nVisiting statement:\n"); |
75a70cf9 | 1713 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
4ee9c684 | 1714 | } |
4ee9c684 | 1715 | |
75a70cf9 | 1716 | switch (gimple_code (stmt)) |
4ee9c684 | 1717 | { |
75a70cf9 | 1718 | case GIMPLE_ASSIGN: |
1719 | /* If the statement is an assignment that produces a single | |
1720 | output value, evaluate its RHS to see if the lattice value of | |
1721 | its output has changed. */ | |
1722 | return visit_assignment (stmt, output_p); | |
1723 | ||
1724 | case GIMPLE_CALL: | |
1725 | /* A value-returning call also performs an assignment. */ | |
1726 | if (gimple_call_lhs (stmt) != NULL_TREE) | |
1727 | return visit_assignment (stmt, output_p); | |
1728 | break; | |
1729 | ||
1730 | case GIMPLE_COND: | |
1731 | case GIMPLE_SWITCH: | |
1732 | /* If STMT is a conditional branch, see if we can determine | |
1733 | which branch will be taken. */ | |
1734 | /* FIXME. It appears that we should be able to optimize | |
1735 | computed GOTOs here as well. */ | |
1736 | return visit_cond_stmt (stmt, taken_edge_p); | |
1737 | ||
1738 | default: | |
1739 | break; | |
4ee9c684 | 1740 | } |
4ee9c684 | 1741 | |
41511585 | 1742 | /* Any other kind of statement is not interesting for constant |
1743 | propagation and, therefore, not worth simulating. */ | |
41511585 | 1744 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1745 | fprintf (dump_file, "No interesting values produced. Marked VARYING.\n"); | |
4ee9c684 | 1746 | |
41511585 | 1747 | /* Definitions made by statements other than assignments to |
1748 | SSA_NAMEs represent unknown modifications to their outputs. | |
1749 | Mark them VARYING. */ | |
88dbf20f | 1750 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) |
1751 | { | |
61207d43 | 1752 | prop_value_t v = { VARYING, NULL_TREE }; |
88dbf20f | 1753 | set_lattice_value (def, v); |
1754 | } | |
4ee9c684 | 1755 | |
41511585 | 1756 | return SSA_PROP_VARYING; |
1757 | } | |
4ee9c684 | 1758 | |
4ee9c684 | 1759 | |
88dbf20f | 1760 | /* Main entry point for SSA Conditional Constant Propagation. */ |
41511585 | 1761 | |
33a34f1e | 1762 | static unsigned int |
61207d43 | 1763 | do_ssa_ccp (void) |
41511585 | 1764 | { |
1765 | ccp_initialize (); | |
1766 | ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node); | |
33a34f1e | 1767 | if (ccp_finalize ()) |
eb9161e7 | 1768 | return (TODO_cleanup_cfg | TODO_update_ssa | TODO_remove_unused_locals); |
33a34f1e | 1769 | else |
1770 | return 0; | |
4ee9c684 | 1771 | } |
1772 | ||
5664499b | 1773 | |
1774 | static bool | |
41511585 | 1775 | gate_ccp (void) |
5664499b | 1776 | { |
41511585 | 1777 | return flag_tree_ccp != 0; |
5664499b | 1778 | } |
1779 | ||
4ee9c684 | 1780 | |
48e1416a | 1781 | struct gimple_opt_pass pass_ccp = |
41511585 | 1782 | { |
20099e35 | 1783 | { |
1784 | GIMPLE_PASS, | |
41511585 | 1785 | "ccp", /* name */ |
1786 | gate_ccp, /* gate */ | |
88dbf20f | 1787 | do_ssa_ccp, /* execute */ |
41511585 | 1788 | NULL, /* sub */ |
1789 | NULL, /* next */ | |
1790 | 0, /* static_pass_number */ | |
1791 | TV_TREE_CCP, /* tv_id */ | |
49290934 | 1792 | PROP_cfg | PROP_ssa, /* properties_required */ |
41511585 | 1793 | 0, /* properties_provided */ |
b6246c40 | 1794 | 0, /* properties_destroyed */ |
41511585 | 1795 | 0, /* todo_flags_start */ |
33a34f1e | 1796 | TODO_dump_func | TODO_verify_ssa |
20099e35 | 1797 | | TODO_verify_stmts | TODO_ggc_collect/* todo_flags_finish */ |
1798 | } | |
41511585 | 1799 | }; |
4ee9c684 | 1800 | |
4ee9c684 | 1801 | |
75a70cf9 | 1802 | |
bdd0e199 | 1803 | /* Try to optimize out __builtin_stack_restore. Optimize it out |
1804 | if there is another __builtin_stack_restore in the same basic | |
1805 | block and no calls or ASM_EXPRs are in between, or if this block's | |
1806 | only outgoing edge is to EXIT_BLOCK and there are no calls or | |
1807 | ASM_EXPRs after this __builtin_stack_restore. */ | |
1808 | ||
1809 | static tree | |
75a70cf9 | 1810 | optimize_stack_restore (gimple_stmt_iterator i) |
bdd0e199 | 1811 | { |
6ea999da | 1812 | tree callee; |
1813 | gimple stmt; | |
75a70cf9 | 1814 | |
1815 | basic_block bb = gsi_bb (i); | |
1816 | gimple call = gsi_stmt (i); | |
bdd0e199 | 1817 | |
75a70cf9 | 1818 | if (gimple_code (call) != GIMPLE_CALL |
1819 | || gimple_call_num_args (call) != 1 | |
1820 | || TREE_CODE (gimple_call_arg (call, 0)) != SSA_NAME | |
1821 | || !POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call, 0)))) | |
bdd0e199 | 1822 | return NULL_TREE; |
1823 | ||
75a70cf9 | 1824 | for (gsi_next (&i); !gsi_end_p (i); gsi_next (&i)) |
bdd0e199 | 1825 | { |
75a70cf9 | 1826 | stmt = gsi_stmt (i); |
1827 | if (gimple_code (stmt) == GIMPLE_ASM) | |
bdd0e199 | 1828 | return NULL_TREE; |
75a70cf9 | 1829 | if (gimple_code (stmt) != GIMPLE_CALL) |
bdd0e199 | 1830 | continue; |
1831 | ||
75a70cf9 | 1832 | callee = gimple_call_fndecl (stmt); |
c40a6f90 | 1833 | if (!callee |
1834 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL | |
1835 | /* All regular builtins are ok, just obviously not alloca. */ | |
1836 | || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA) | |
bdd0e199 | 1837 | return NULL_TREE; |
1838 | ||
1839 | if (DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_RESTORE) | |
6ea999da | 1840 | goto second_stack_restore; |
bdd0e199 | 1841 | } |
1842 | ||
6ea999da | 1843 | if (!gsi_end_p (i)) |
bdd0e199 | 1844 | return NULL_TREE; |
1845 | ||
6ea999da | 1846 | /* Allow one successor of the exit block, or zero successors. */ |
1847 | switch (EDGE_COUNT (bb->succs)) | |
1848 | { | |
1849 | case 0: | |
1850 | break; | |
1851 | case 1: | |
1852 | if (single_succ_edge (bb)->dest != EXIT_BLOCK_PTR) | |
1853 | return NULL_TREE; | |
1854 | break; | |
1855 | default: | |
1856 | return NULL_TREE; | |
1857 | } | |
1858 | second_stack_restore: | |
bdd0e199 | 1859 | |
6ea999da | 1860 | /* If there's exactly one use, then zap the call to __builtin_stack_save. |
1861 | If there are multiple uses, then the last one should remove the call. | |
1862 | In any case, whether the call to __builtin_stack_save can be removed | |
1863 | or not is irrelevant to removing the call to __builtin_stack_restore. */ | |
1864 | if (has_single_use (gimple_call_arg (call, 0))) | |
1865 | { | |
1866 | gimple stack_save = SSA_NAME_DEF_STMT (gimple_call_arg (call, 0)); | |
1867 | if (is_gimple_call (stack_save)) | |
1868 | { | |
1869 | callee = gimple_call_fndecl (stack_save); | |
1870 | if (callee | |
1871 | && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL | |
1872 | && DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_SAVE) | |
1873 | { | |
1874 | gimple_stmt_iterator stack_save_gsi; | |
1875 | tree rhs; | |
bdd0e199 | 1876 | |
6ea999da | 1877 | stack_save_gsi = gsi_for_stmt (stack_save); |
1878 | rhs = build_int_cst (TREE_TYPE (gimple_call_arg (call, 0)), 0); | |
1879 | update_call_from_tree (&stack_save_gsi, rhs); | |
1880 | } | |
1881 | } | |
1882 | } | |
bdd0e199 | 1883 | |
75a70cf9 | 1884 | /* No effect, so the statement will be deleted. */ |
bdd0e199 | 1885 | return integer_zero_node; |
1886 | } | |
75a70cf9 | 1887 | |
8a58ed0a | 1888 | /* If va_list type is a simple pointer and nothing special is needed, |
1889 | optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0), | |
1890 | __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple | |
1891 | pointer assignment. */ | |
1892 | ||
1893 | static tree | |
75a70cf9 | 1894 | optimize_stdarg_builtin (gimple call) |
8a58ed0a | 1895 | { |
5f57a8b1 | 1896 | tree callee, lhs, rhs, cfun_va_list; |
8a58ed0a | 1897 | bool va_list_simple_ptr; |
389dd41b | 1898 | location_t loc = gimple_location (call); |
8a58ed0a | 1899 | |
75a70cf9 | 1900 | if (gimple_code (call) != GIMPLE_CALL) |
8a58ed0a | 1901 | return NULL_TREE; |
1902 | ||
75a70cf9 | 1903 | callee = gimple_call_fndecl (call); |
5f57a8b1 | 1904 | |
1905 | cfun_va_list = targetm.fn_abi_va_list (callee); | |
1906 | va_list_simple_ptr = POINTER_TYPE_P (cfun_va_list) | |
1907 | && (TREE_TYPE (cfun_va_list) == void_type_node | |
1908 | || TREE_TYPE (cfun_va_list) == char_type_node); | |
1909 | ||
8a58ed0a | 1910 | switch (DECL_FUNCTION_CODE (callee)) |
1911 | { | |
1912 | case BUILT_IN_VA_START: | |
1913 | if (!va_list_simple_ptr | |
1914 | || targetm.expand_builtin_va_start != NULL | |
75a70cf9 | 1915 | || built_in_decls[BUILT_IN_NEXT_ARG] == NULL) |
8a58ed0a | 1916 | return NULL_TREE; |
1917 | ||
75a70cf9 | 1918 | if (gimple_call_num_args (call) != 2) |
8a58ed0a | 1919 | return NULL_TREE; |
1920 | ||
75a70cf9 | 1921 | lhs = gimple_call_arg (call, 0); |
8a58ed0a | 1922 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) |
1923 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
5f57a8b1 | 1924 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
8a58ed0a | 1925 | return NULL_TREE; |
48e1416a | 1926 | |
389dd41b | 1927 | lhs = build_fold_indirect_ref_loc (loc, lhs); |
1928 | rhs = build_call_expr_loc (loc, built_in_decls[BUILT_IN_NEXT_ARG], | |
75a70cf9 | 1929 | 1, integer_zero_node); |
389dd41b | 1930 | rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); |
8a58ed0a | 1931 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); |
1932 | ||
1933 | case BUILT_IN_VA_COPY: | |
1934 | if (!va_list_simple_ptr) | |
1935 | return NULL_TREE; | |
1936 | ||
75a70cf9 | 1937 | if (gimple_call_num_args (call) != 2) |
8a58ed0a | 1938 | return NULL_TREE; |
1939 | ||
75a70cf9 | 1940 | lhs = gimple_call_arg (call, 0); |
8a58ed0a | 1941 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) |
1942 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
5f57a8b1 | 1943 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
8a58ed0a | 1944 | return NULL_TREE; |
1945 | ||
389dd41b | 1946 | lhs = build_fold_indirect_ref_loc (loc, lhs); |
75a70cf9 | 1947 | rhs = gimple_call_arg (call, 1); |
8a58ed0a | 1948 | if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs)) |
5f57a8b1 | 1949 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
8a58ed0a | 1950 | return NULL_TREE; |
1951 | ||
389dd41b | 1952 | rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); |
8a58ed0a | 1953 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); |
1954 | ||
1955 | case BUILT_IN_VA_END: | |
75a70cf9 | 1956 | /* No effect, so the statement will be deleted. */ |
8a58ed0a | 1957 | return integer_zero_node; |
1958 | ||
1959 | default: | |
1960 | gcc_unreachable (); | |
1961 | } | |
1962 | } | |
75a70cf9 | 1963 | |
4ee9c684 | 1964 | /* A simple pass that attempts to fold all builtin functions. This pass |
1965 | is run after we've propagated as many constants as we can. */ | |
1966 | ||
2a1990e9 | 1967 | static unsigned int |
4ee9c684 | 1968 | execute_fold_all_builtins (void) |
1969 | { | |
b36237eb | 1970 | bool cfg_changed = false; |
4ee9c684 | 1971 | basic_block bb; |
b1b7c0c4 | 1972 | unsigned int todoflags = 0; |
48e1416a | 1973 | |
4ee9c684 | 1974 | FOR_EACH_BB (bb) |
1975 | { | |
75a70cf9 | 1976 | gimple_stmt_iterator i; |
1977 | for (i = gsi_start_bb (bb); !gsi_end_p (i); ) | |
4ee9c684 | 1978 | { |
75a70cf9 | 1979 | gimple stmt, old_stmt; |
4ee9c684 | 1980 | tree callee, result; |
0a39fd54 | 1981 | enum built_in_function fcode; |
4ee9c684 | 1982 | |
75a70cf9 | 1983 | stmt = gsi_stmt (i); |
1984 | ||
1985 | if (gimple_code (stmt) != GIMPLE_CALL) | |
0a39fd54 | 1986 | { |
75a70cf9 | 1987 | gsi_next (&i); |
0a39fd54 | 1988 | continue; |
1989 | } | |
75a70cf9 | 1990 | callee = gimple_call_fndecl (stmt); |
4ee9c684 | 1991 | if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) |
0a39fd54 | 1992 | { |
75a70cf9 | 1993 | gsi_next (&i); |
0a39fd54 | 1994 | continue; |
1995 | } | |
1996 | fcode = DECL_FUNCTION_CODE (callee); | |
4ee9c684 | 1997 | |
2d18b16d | 1998 | result = gimple_fold_builtin (stmt); |
5a4b7e1e | 1999 | |
2000 | if (result) | |
75a70cf9 | 2001 | gimple_remove_stmt_histograms (cfun, stmt); |
5a4b7e1e | 2002 | |
4ee9c684 | 2003 | if (!result) |
2004 | switch (DECL_FUNCTION_CODE (callee)) | |
2005 | { | |
2006 | case BUILT_IN_CONSTANT_P: | |
2007 | /* Resolve __builtin_constant_p. If it hasn't been | |
2008 | folded to integer_one_node by now, it's fairly | |
2009 | certain that the value simply isn't constant. */ | |
75a70cf9 | 2010 | result = integer_zero_node; |
4ee9c684 | 2011 | break; |
2012 | ||
bdd0e199 | 2013 | case BUILT_IN_STACK_RESTORE: |
75a70cf9 | 2014 | result = optimize_stack_restore (i); |
8a58ed0a | 2015 | if (result) |
2016 | break; | |
75a70cf9 | 2017 | gsi_next (&i); |
8a58ed0a | 2018 | continue; |
2019 | ||
2020 | case BUILT_IN_VA_START: | |
2021 | case BUILT_IN_VA_END: | |
2022 | case BUILT_IN_VA_COPY: | |
2023 | /* These shouldn't be folded before pass_stdarg. */ | |
75a70cf9 | 2024 | result = optimize_stdarg_builtin (stmt); |
bdd0e199 | 2025 | if (result) |
2026 | break; | |
2027 | /* FALLTHRU */ | |
2028 | ||
4ee9c684 | 2029 | default: |
75a70cf9 | 2030 | gsi_next (&i); |
4ee9c684 | 2031 | continue; |
2032 | } | |
2033 | ||
2034 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2035 | { | |
2036 | fprintf (dump_file, "Simplified\n "); | |
75a70cf9 | 2037 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
4ee9c684 | 2038 | } |
2039 | ||
75a70cf9 | 2040 | old_stmt = stmt; |
75a70cf9 | 2041 | if (!update_call_from_tree (&i, result)) |
0fefde02 | 2042 | { |
2043 | gimplify_and_update_call_from_tree (&i, result); | |
2044 | todoflags |= TODO_update_address_taken; | |
2045 | } | |
de6ed584 | 2046 | |
75a70cf9 | 2047 | stmt = gsi_stmt (i); |
4c5fd53c | 2048 | update_stmt (stmt); |
de6ed584 | 2049 | |
75a70cf9 | 2050 | if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt) |
2051 | && gimple_purge_dead_eh_edges (bb)) | |
b36237eb | 2052 | cfg_changed = true; |
4ee9c684 | 2053 | |
2054 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2055 | { | |
2056 | fprintf (dump_file, "to\n "); | |
75a70cf9 | 2057 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
4ee9c684 | 2058 | fprintf (dump_file, "\n"); |
2059 | } | |
0a39fd54 | 2060 | |
2061 | /* Retry the same statement if it changed into another | |
2062 | builtin, there might be new opportunities now. */ | |
75a70cf9 | 2063 | if (gimple_code (stmt) != GIMPLE_CALL) |
0a39fd54 | 2064 | { |
75a70cf9 | 2065 | gsi_next (&i); |
0a39fd54 | 2066 | continue; |
2067 | } | |
75a70cf9 | 2068 | callee = gimple_call_fndecl (stmt); |
0a39fd54 | 2069 | if (!callee |
75a70cf9 | 2070 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL |
0a39fd54 | 2071 | || DECL_FUNCTION_CODE (callee) == fcode) |
75a70cf9 | 2072 | gsi_next (&i); |
4ee9c684 | 2073 | } |
2074 | } | |
48e1416a | 2075 | |
b36237eb | 2076 | /* Delete unreachable blocks. */ |
b1b7c0c4 | 2077 | if (cfg_changed) |
2078 | todoflags |= TODO_cleanup_cfg; | |
48e1416a | 2079 | |
b1b7c0c4 | 2080 | return todoflags; |
4ee9c684 | 2081 | } |
2082 | ||
41511585 | 2083 | |
48e1416a | 2084 | struct gimple_opt_pass pass_fold_builtins = |
4ee9c684 | 2085 | { |
20099e35 | 2086 | { |
2087 | GIMPLE_PASS, | |
4ee9c684 | 2088 | "fab", /* name */ |
2089 | NULL, /* gate */ | |
2090 | execute_fold_all_builtins, /* execute */ | |
2091 | NULL, /* sub */ | |
2092 | NULL, /* next */ | |
2093 | 0, /* static_pass_number */ | |
0b1615c1 | 2094 | TV_NONE, /* tv_id */ |
49290934 | 2095 | PROP_cfg | PROP_ssa, /* properties_required */ |
4ee9c684 | 2096 | 0, /* properties_provided */ |
2097 | 0, /* properties_destroyed */ | |
2098 | 0, /* todo_flags_start */ | |
909e5ecb | 2099 | TODO_dump_func |
2100 | | TODO_verify_ssa | |
20099e35 | 2101 | | TODO_update_ssa /* todo_flags_finish */ |
2102 | } | |
4ee9c684 | 2103 | }; |