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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 | ||
4ee9c684 | 102 | References: |
103 | ||
104 | Constant propagation with conditional branches, | |
105 | Wegman and Zadeck, ACM TOPLAS 13(2):181-210. | |
106 | ||
107 | Building an Optimizing Compiler, | |
108 | Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9. | |
109 | ||
110 | Advanced Compiler Design and Implementation, | |
111 | Steven Muchnick, Morgan Kaufmann, 1997, Section 12.6 */ | |
112 | ||
113 | #include "config.h" | |
114 | #include "system.h" | |
115 | #include "coretypes.h" | |
116 | #include "tm.h" | |
4ee9c684 | 117 | #include "tree.h" |
41511585 | 118 | #include "flags.h" |
4ee9c684 | 119 | #include "tm_p.h" |
4ee9c684 | 120 | #include "basic-block.h" |
41511585 | 121 | #include "output.h" |
41511585 | 122 | #include "function.h" |
ce084dfc | 123 | #include "tree-pretty-print.h" |
124 | #include "gimple-pretty-print.h" | |
41511585 | 125 | #include "timevar.h" |
4ee9c684 | 126 | #include "tree-dump.h" |
41511585 | 127 | #include "tree-flow.h" |
4ee9c684 | 128 | #include "tree-pass.h" |
41511585 | 129 | #include "tree-ssa-propagate.h" |
5a4b7e1e | 130 | #include "value-prof.h" |
41511585 | 131 | #include "langhooks.h" |
8782adcf | 132 | #include "target.h" |
0b205f4c | 133 | #include "diagnostic-core.h" |
43fb76c1 | 134 | #include "dbgcnt.h" |
4ee9c684 | 135 | |
136 | ||
137 | /* Possible lattice values. */ | |
138 | typedef enum | |
139 | { | |
bfa30570 | 140 | UNINITIALIZED, |
4ee9c684 | 141 | UNDEFINED, |
142 | CONSTANT, | |
143 | VARYING | |
88dbf20f | 144 | } ccp_lattice_t; |
4ee9c684 | 145 | |
14f101cf | 146 | struct prop_value_d { |
147 | /* Lattice value. */ | |
148 | ccp_lattice_t lattice_val; | |
149 | ||
150 | /* Propagated value. */ | |
151 | tree value; | |
b7e55469 | 152 | |
153 | /* Mask that applies to the propagated value during CCP. For | |
154 | X with a CONSTANT lattice value X & ~mask == value & ~mask. */ | |
155 | double_int mask; | |
14f101cf | 156 | }; |
157 | ||
158 | typedef struct prop_value_d prop_value_t; | |
159 | ||
88dbf20f | 160 | /* Array of propagated constant values. After propagation, |
161 | CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If | |
162 | the constant is held in an SSA name representing a memory store | |
4fb5e5ca | 163 | (i.e., a VDEF), CONST_VAL[I].MEM_REF will contain the actual |
164 | memory reference used to store (i.e., the LHS of the assignment | |
165 | doing the store). */ | |
20140406 | 166 | static prop_value_t *const_val; |
4ee9c684 | 167 | |
4af351a8 | 168 | static void canonicalize_float_value (prop_value_t *); |
6688f8ec | 169 | static bool ccp_fold_stmt (gimple_stmt_iterator *); |
83f4b93b | 170 | static tree fold_ctor_reference (tree type, tree ctor, |
171 | unsigned HOST_WIDE_INT offset, | |
172 | unsigned HOST_WIDE_INT size); | |
4af351a8 | 173 | |
88dbf20f | 174 | /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */ |
01406fc0 | 175 | |
176 | static void | |
88dbf20f | 177 | dump_lattice_value (FILE *outf, const char *prefix, prop_value_t val) |
01406fc0 | 178 | { |
41511585 | 179 | switch (val.lattice_val) |
01406fc0 | 180 | { |
88dbf20f | 181 | case UNINITIALIZED: |
182 | fprintf (outf, "%sUNINITIALIZED", prefix); | |
183 | break; | |
41511585 | 184 | case UNDEFINED: |
185 | fprintf (outf, "%sUNDEFINED", prefix); | |
186 | break; | |
187 | case VARYING: | |
188 | fprintf (outf, "%sVARYING", prefix); | |
189 | break; | |
41511585 | 190 | case CONSTANT: |
191 | fprintf (outf, "%sCONSTANT ", prefix); | |
b7e55469 | 192 | if (TREE_CODE (val.value) != INTEGER_CST |
193 | || double_int_zero_p (val.mask)) | |
194 | print_generic_expr (outf, val.value, dump_flags); | |
195 | else | |
196 | { | |
197 | double_int cval = double_int_and_not (tree_to_double_int (val.value), | |
198 | val.mask); | |
199 | fprintf (outf, "%sCONSTANT " HOST_WIDE_INT_PRINT_DOUBLE_HEX, | |
200 | prefix, cval.high, cval.low); | |
201 | fprintf (outf, " (" HOST_WIDE_INT_PRINT_DOUBLE_HEX ")", | |
202 | val.mask.high, val.mask.low); | |
203 | } | |
41511585 | 204 | break; |
205 | default: | |
8c0963c4 | 206 | gcc_unreachable (); |
41511585 | 207 | } |
01406fc0 | 208 | } |
4ee9c684 | 209 | |
4ee9c684 | 210 | |
88dbf20f | 211 | /* Print lattice value VAL to stderr. */ |
212 | ||
213 | void debug_lattice_value (prop_value_t val); | |
214 | ||
4b987fac | 215 | DEBUG_FUNCTION void |
88dbf20f | 216 | debug_lattice_value (prop_value_t val) |
217 | { | |
218 | dump_lattice_value (stderr, "", val); | |
219 | fprintf (stderr, "\n"); | |
220 | } | |
4ee9c684 | 221 | |
4ee9c684 | 222 | |
88dbf20f | 223 | /* Compute a default value for variable VAR and store it in the |
224 | CONST_VAL array. The following rules are used to get default | |
225 | values: | |
01406fc0 | 226 | |
88dbf20f | 227 | 1- Global and static variables that are declared constant are |
228 | considered CONSTANT. | |
229 | ||
230 | 2- Any other value is considered UNDEFINED. This is useful when | |
41511585 | 231 | considering PHI nodes. PHI arguments that are undefined do not |
232 | change the constant value of the PHI node, which allows for more | |
88dbf20f | 233 | constants to be propagated. |
4ee9c684 | 234 | |
8883e700 | 235 | 3- Variables defined by statements other than assignments and PHI |
88dbf20f | 236 | nodes are considered VARYING. |
4ee9c684 | 237 | |
8883e700 | 238 | 4- Initial values of variables that are not GIMPLE registers are |
bfa30570 | 239 | considered VARYING. */ |
4ee9c684 | 240 | |
88dbf20f | 241 | static prop_value_t |
242 | get_default_value (tree var) | |
243 | { | |
244 | tree sym = SSA_NAME_VAR (var); | |
b7e55469 | 245 | prop_value_t val = { UNINITIALIZED, NULL_TREE, { 0, 0 } }; |
8edeb88b | 246 | gimple stmt; |
247 | ||
248 | stmt = SSA_NAME_DEF_STMT (var); | |
249 | ||
250 | if (gimple_nop_p (stmt)) | |
4ee9c684 | 251 | { |
8edeb88b | 252 | /* Variables defined by an empty statement are those used |
253 | before being initialized. If VAR is a local variable, we | |
254 | can assume initially that it is UNDEFINED, otherwise we must | |
255 | consider it VARYING. */ | |
524a0531 | 256 | if (is_gimple_reg (sym) |
257 | && TREE_CODE (sym) == VAR_DECL) | |
8edeb88b | 258 | val.lattice_val = UNDEFINED; |
259 | else | |
b7e55469 | 260 | { |
261 | val.lattice_val = VARYING; | |
262 | val.mask = double_int_minus_one; | |
263 | } | |
4ee9c684 | 264 | } |
8edeb88b | 265 | else if (is_gimple_assign (stmt) |
266 | /* Value-returning GIMPLE_CALL statements assign to | |
267 | a variable, and are treated similarly to GIMPLE_ASSIGN. */ | |
268 | || (is_gimple_call (stmt) | |
269 | && gimple_call_lhs (stmt) != NULL_TREE) | |
270 | || gimple_code (stmt) == GIMPLE_PHI) | |
41511585 | 271 | { |
8edeb88b | 272 | tree cst; |
273 | if (gimple_assign_single_p (stmt) | |
274 | && DECL_P (gimple_assign_rhs1 (stmt)) | |
275 | && (cst = get_symbol_constant_value (gimple_assign_rhs1 (stmt)))) | |
88dbf20f | 276 | { |
8edeb88b | 277 | val.lattice_val = CONSTANT; |
278 | val.value = cst; | |
88dbf20f | 279 | } |
280 | else | |
8edeb88b | 281 | /* Any other variable defined by an assignment or a PHI node |
282 | is considered UNDEFINED. */ | |
283 | val.lattice_val = UNDEFINED; | |
284 | } | |
285 | else | |
286 | { | |
287 | /* Otherwise, VAR will never take on a constant value. */ | |
288 | val.lattice_val = VARYING; | |
b7e55469 | 289 | val.mask = double_int_minus_one; |
41511585 | 290 | } |
4ee9c684 | 291 | |
41511585 | 292 | return val; |
293 | } | |
4ee9c684 | 294 | |
4ee9c684 | 295 | |
bfa30570 | 296 | /* Get the constant value associated with variable VAR. */ |
4ee9c684 | 297 | |
bfa30570 | 298 | static inline prop_value_t * |
299 | get_value (tree var) | |
88dbf20f | 300 | { |
e004838d | 301 | prop_value_t *val; |
bfa30570 | 302 | |
e004838d | 303 | if (const_val == NULL) |
304 | return NULL; | |
305 | ||
306 | val = &const_val[SSA_NAME_VERSION (var)]; | |
bfa30570 | 307 | if (val->lattice_val == UNINITIALIZED) |
4ee9c684 | 308 | *val = get_default_value (var); |
309 | ||
4af351a8 | 310 | canonicalize_float_value (val); |
311 | ||
4ee9c684 | 312 | return val; |
313 | } | |
314 | ||
15d138c9 | 315 | /* Return the constant tree value associated with VAR. */ |
316 | ||
317 | static inline tree | |
318 | get_constant_value (tree var) | |
319 | { | |
98d92e3c | 320 | prop_value_t *val; |
321 | if (TREE_CODE (var) != SSA_NAME) | |
322 | { | |
323 | if (is_gimple_min_invariant (var)) | |
324 | return var; | |
325 | return NULL_TREE; | |
326 | } | |
327 | val = get_value (var); | |
b7e55469 | 328 | if (val |
329 | && val->lattice_val == CONSTANT | |
330 | && (TREE_CODE (val->value) != INTEGER_CST | |
331 | || double_int_zero_p (val->mask))) | |
15d138c9 | 332 | return val->value; |
333 | return NULL_TREE; | |
334 | } | |
335 | ||
bfa30570 | 336 | /* Sets the value associated with VAR to VARYING. */ |
337 | ||
338 | static inline void | |
339 | set_value_varying (tree var) | |
340 | { | |
341 | prop_value_t *val = &const_val[SSA_NAME_VERSION (var)]; | |
342 | ||
343 | val->lattice_val = VARYING; | |
344 | val->value = NULL_TREE; | |
b7e55469 | 345 | val->mask = double_int_minus_one; |
bfa30570 | 346 | } |
4ee9c684 | 347 | |
b31eb493 | 348 | /* For float types, modify the value of VAL to make ccp work correctly |
349 | for non-standard values (-0, NaN): | |
350 | ||
351 | If HONOR_SIGNED_ZEROS is false, and VAL = -0, we canonicalize it to 0. | |
352 | If HONOR_NANS is false, and VAL is NaN, we canonicalize it to UNDEFINED. | |
353 | This is to fix the following problem (see PR 29921): Suppose we have | |
354 | ||
355 | x = 0.0 * y | |
356 | ||
357 | and we set value of y to NaN. This causes value of x to be set to NaN. | |
358 | When we later determine that y is in fact VARYING, fold uses the fact | |
359 | that HONOR_NANS is false, and we try to change the value of x to 0, | |
360 | causing an ICE. With HONOR_NANS being false, the real appearance of | |
361 | NaN would cause undefined behavior, though, so claiming that y (and x) | |
362 | are UNDEFINED initially is correct. */ | |
363 | ||
364 | static void | |
365 | canonicalize_float_value (prop_value_t *val) | |
366 | { | |
367 | enum machine_mode mode; | |
368 | tree type; | |
369 | REAL_VALUE_TYPE d; | |
370 | ||
371 | if (val->lattice_val != CONSTANT | |
372 | || TREE_CODE (val->value) != REAL_CST) | |
373 | return; | |
374 | ||
375 | d = TREE_REAL_CST (val->value); | |
376 | type = TREE_TYPE (val->value); | |
377 | mode = TYPE_MODE (type); | |
378 | ||
379 | if (!HONOR_SIGNED_ZEROS (mode) | |
380 | && REAL_VALUE_MINUS_ZERO (d)) | |
381 | { | |
382 | val->value = build_real (type, dconst0); | |
383 | return; | |
384 | } | |
385 | ||
386 | if (!HONOR_NANS (mode) | |
387 | && REAL_VALUE_ISNAN (d)) | |
388 | { | |
389 | val->lattice_val = UNDEFINED; | |
390 | val->value = NULL; | |
b31eb493 | 391 | return; |
392 | } | |
393 | } | |
394 | ||
b7e55469 | 395 | /* Return whether the lattice transition is valid. */ |
396 | ||
397 | static bool | |
398 | valid_lattice_transition (prop_value_t old_val, prop_value_t new_val) | |
399 | { | |
400 | /* Lattice transitions must always be monotonically increasing in | |
401 | value. */ | |
402 | if (old_val.lattice_val < new_val.lattice_val) | |
403 | return true; | |
404 | ||
405 | if (old_val.lattice_val != new_val.lattice_val) | |
406 | return false; | |
407 | ||
408 | if (!old_val.value && !new_val.value) | |
409 | return true; | |
410 | ||
411 | /* Now both lattice values are CONSTANT. */ | |
412 | ||
413 | /* Allow transitioning from &x to &x & ~3. */ | |
414 | if (TREE_CODE (old_val.value) != INTEGER_CST | |
415 | && TREE_CODE (new_val.value) == INTEGER_CST) | |
416 | return true; | |
417 | ||
418 | /* Bit-lattices have to agree in the still valid bits. */ | |
419 | if (TREE_CODE (old_val.value) == INTEGER_CST | |
420 | && TREE_CODE (new_val.value) == INTEGER_CST) | |
421 | return double_int_equal_p | |
422 | (double_int_and_not (tree_to_double_int (old_val.value), | |
423 | new_val.mask), | |
424 | double_int_and_not (tree_to_double_int (new_val.value), | |
425 | new_val.mask)); | |
426 | ||
427 | /* Otherwise constant values have to agree. */ | |
428 | return operand_equal_p (old_val.value, new_val.value, 0); | |
429 | } | |
430 | ||
88dbf20f | 431 | /* Set the value for variable VAR to NEW_VAL. Return true if the new |
432 | value is different from VAR's previous value. */ | |
4ee9c684 | 433 | |
41511585 | 434 | static bool |
88dbf20f | 435 | set_lattice_value (tree var, prop_value_t new_val) |
4ee9c684 | 436 | { |
6d0bf6d6 | 437 | /* We can deal with old UNINITIALIZED values just fine here. */ |
438 | prop_value_t *old_val = &const_val[SSA_NAME_VERSION (var)]; | |
88dbf20f | 439 | |
b31eb493 | 440 | canonicalize_float_value (&new_val); |
441 | ||
b7e55469 | 442 | /* We have to be careful to not go up the bitwise lattice |
443 | represented by the mask. | |
444 | ??? This doesn't seem to be the best place to enforce this. */ | |
445 | if (new_val.lattice_val == CONSTANT | |
446 | && old_val->lattice_val == CONSTANT | |
447 | && TREE_CODE (new_val.value) == INTEGER_CST | |
448 | && TREE_CODE (old_val->value) == INTEGER_CST) | |
449 | { | |
450 | double_int diff; | |
451 | diff = double_int_xor (tree_to_double_int (new_val.value), | |
452 | tree_to_double_int (old_val->value)); | |
453 | new_val.mask = double_int_ior (new_val.mask, | |
454 | double_int_ior (old_val->mask, diff)); | |
455 | } | |
bfa30570 | 456 | |
b7e55469 | 457 | gcc_assert (valid_lattice_transition (*old_val, new_val)); |
88dbf20f | 458 | |
b7e55469 | 459 | /* If *OLD_VAL and NEW_VAL are the same, return false to inform the |
460 | caller that this was a non-transition. */ | |
461 | if (old_val->lattice_val != new_val.lattice_val | |
462 | || (new_val.lattice_val == CONSTANT | |
463 | && TREE_CODE (new_val.value) == INTEGER_CST | |
464 | && (TREE_CODE (old_val->value) != INTEGER_CST | |
465 | || !double_int_equal_p (new_val.mask, old_val->mask)))) | |
4ee9c684 | 466 | { |
b7e55469 | 467 | /* ??? We would like to delay creation of INTEGER_CSTs from |
468 | partially constants here. */ | |
469 | ||
41511585 | 470 | if (dump_file && (dump_flags & TDF_DETAILS)) |
471 | { | |
88dbf20f | 472 | dump_lattice_value (dump_file, "Lattice value changed to ", new_val); |
bfa30570 | 473 | fprintf (dump_file, ". Adding SSA edges to worklist.\n"); |
41511585 | 474 | } |
475 | ||
88dbf20f | 476 | *old_val = new_val; |
477 | ||
6d0bf6d6 | 478 | gcc_assert (new_val.lattice_val != UNINITIALIZED); |
bfa30570 | 479 | return true; |
4ee9c684 | 480 | } |
41511585 | 481 | |
482 | return false; | |
4ee9c684 | 483 | } |
484 | ||
b7e55469 | 485 | static prop_value_t get_value_for_expr (tree, bool); |
486 | static prop_value_t bit_value_binop (enum tree_code, tree, tree, tree); | |
487 | static void bit_value_binop_1 (enum tree_code, tree, double_int *, double_int *, | |
488 | tree, double_int, double_int, | |
489 | tree, double_int, double_int); | |
490 | ||
491 | /* Return a double_int that can be used for bitwise simplifications | |
492 | from VAL. */ | |
493 | ||
494 | static double_int | |
495 | value_to_double_int (prop_value_t val) | |
496 | { | |
497 | if (val.value | |
498 | && TREE_CODE (val.value) == INTEGER_CST) | |
499 | return tree_to_double_int (val.value); | |
500 | else | |
501 | return double_int_zero; | |
502 | } | |
503 | ||
504 | /* Return the value for the address expression EXPR based on alignment | |
505 | information. */ | |
6d0bf6d6 | 506 | |
507 | static prop_value_t | |
b7e55469 | 508 | get_value_from_alignment (tree expr) |
509 | { | |
510 | prop_value_t val; | |
511 | HOST_WIDE_INT bitsize, bitpos; | |
512 | tree base, offset; | |
513 | enum machine_mode mode; | |
514 | int align; | |
515 | ||
516 | gcc_assert (TREE_CODE (expr) == ADDR_EXPR); | |
517 | ||
518 | base = get_inner_reference (TREE_OPERAND (expr, 0), | |
519 | &bitsize, &bitpos, &offset, | |
520 | &mode, &align, &align, false); | |
5d9de213 | 521 | if (TREE_CODE (base) == MEM_REF) |
b7e55469 | 522 | val = bit_value_binop (PLUS_EXPR, TREE_TYPE (expr), |
523 | TREE_OPERAND (base, 0), TREE_OPERAND (base, 1)); | |
524 | else if (base | |
98ab9e8f | 525 | && ((align = get_object_alignment (base, BIGGEST_ALIGNMENT)) |
b7e55469 | 526 | > BITS_PER_UNIT)) |
527 | { | |
528 | val.lattice_val = CONSTANT; | |
529 | /* We assume pointers are zero-extended. */ | |
530 | val.mask = double_int_and_not | |
531 | (double_int_mask (TYPE_PRECISION (TREE_TYPE (expr))), | |
532 | uhwi_to_double_int (align / BITS_PER_UNIT - 1)); | |
533 | val.value = build_int_cst (TREE_TYPE (expr), 0); | |
534 | } | |
535 | else | |
536 | { | |
537 | val.lattice_val = VARYING; | |
538 | val.mask = double_int_minus_one; | |
539 | val.value = NULL_TREE; | |
540 | } | |
541 | if (bitpos != 0) | |
542 | { | |
543 | double_int value, mask; | |
544 | bit_value_binop_1 (PLUS_EXPR, TREE_TYPE (expr), &value, &mask, | |
545 | TREE_TYPE (expr), value_to_double_int (val), val.mask, | |
546 | TREE_TYPE (expr), | |
547 | shwi_to_double_int (bitpos / BITS_PER_UNIT), | |
548 | double_int_zero); | |
549 | val.lattice_val = double_int_minus_one_p (mask) ? VARYING : CONSTANT; | |
550 | val.mask = mask; | |
551 | if (val.lattice_val == CONSTANT) | |
552 | val.value = double_int_to_tree (TREE_TYPE (expr), value); | |
553 | else | |
554 | val.value = NULL_TREE; | |
555 | } | |
556 | /* ??? We should handle i * 4 and more complex expressions from | |
557 | the offset, possibly by just expanding get_value_for_expr. */ | |
558 | if (offset != NULL_TREE) | |
559 | { | |
560 | double_int value, mask; | |
561 | prop_value_t oval = get_value_for_expr (offset, true); | |
562 | bit_value_binop_1 (PLUS_EXPR, TREE_TYPE (expr), &value, &mask, | |
563 | TREE_TYPE (expr), value_to_double_int (val), val.mask, | |
564 | TREE_TYPE (expr), value_to_double_int (oval), | |
565 | oval.mask); | |
566 | val.mask = mask; | |
567 | if (double_int_minus_one_p (mask)) | |
568 | { | |
569 | val.lattice_val = VARYING; | |
570 | val.value = NULL_TREE; | |
571 | } | |
572 | else | |
573 | { | |
574 | val.lattice_val = CONSTANT; | |
575 | val.value = double_int_to_tree (TREE_TYPE (expr), value); | |
576 | } | |
577 | } | |
578 | ||
579 | return val; | |
580 | } | |
581 | ||
582 | /* Return the value for the tree operand EXPR. If FOR_BITS_P is true | |
583 | return constant bits extracted from alignment information for | |
584 | invariant addresses. */ | |
585 | ||
586 | static prop_value_t | |
587 | get_value_for_expr (tree expr, bool for_bits_p) | |
6d0bf6d6 | 588 | { |
589 | prop_value_t val; | |
590 | ||
591 | if (TREE_CODE (expr) == SSA_NAME) | |
b7e55469 | 592 | { |
593 | val = *get_value (expr); | |
594 | if (for_bits_p | |
595 | && val.lattice_val == CONSTANT | |
596 | && TREE_CODE (val.value) == ADDR_EXPR) | |
597 | val = get_value_from_alignment (val.value); | |
598 | } | |
599 | else if (is_gimple_min_invariant (expr) | |
600 | && (!for_bits_p || TREE_CODE (expr) != ADDR_EXPR)) | |
6d0bf6d6 | 601 | { |
602 | val.lattice_val = CONSTANT; | |
603 | val.value = expr; | |
b7e55469 | 604 | val.mask = double_int_zero; |
6d0bf6d6 | 605 | canonicalize_float_value (&val); |
606 | } | |
b7e55469 | 607 | else if (TREE_CODE (expr) == ADDR_EXPR) |
608 | val = get_value_from_alignment (expr); | |
6d0bf6d6 | 609 | else |
610 | { | |
611 | val.lattice_val = VARYING; | |
b7e55469 | 612 | val.mask = double_int_minus_one; |
6d0bf6d6 | 613 | val.value = NULL_TREE; |
614 | } | |
6d0bf6d6 | 615 | return val; |
616 | } | |
617 | ||
88dbf20f | 618 | /* Return the likely CCP lattice value for STMT. |
4ee9c684 | 619 | |
41511585 | 620 | If STMT has no operands, then return CONSTANT. |
4ee9c684 | 621 | |
d61b9af3 | 622 | Else if undefinedness of operands of STMT cause its value to be |
623 | undefined, then return UNDEFINED. | |
4ee9c684 | 624 | |
41511585 | 625 | Else if any operands of STMT are constants, then return CONSTANT. |
4ee9c684 | 626 | |
41511585 | 627 | Else return VARYING. */ |
4ee9c684 | 628 | |
88dbf20f | 629 | static ccp_lattice_t |
75a70cf9 | 630 | likely_value (gimple stmt) |
41511585 | 631 | { |
d61b9af3 | 632 | bool has_constant_operand, has_undefined_operand, all_undefined_operands; |
41511585 | 633 | tree use; |
634 | ssa_op_iter iter; | |
8edeb88b | 635 | unsigned i; |
4ee9c684 | 636 | |
590c3166 | 637 | enum gimple_code code = gimple_code (stmt); |
75a70cf9 | 638 | |
639 | /* This function appears to be called only for assignments, calls, | |
640 | conditionals, and switches, due to the logic in visit_stmt. */ | |
641 | gcc_assert (code == GIMPLE_ASSIGN | |
642 | || code == GIMPLE_CALL | |
643 | || code == GIMPLE_COND | |
644 | || code == GIMPLE_SWITCH); | |
88dbf20f | 645 | |
646 | /* If the statement has volatile operands, it won't fold to a | |
647 | constant value. */ | |
75a70cf9 | 648 | if (gimple_has_volatile_ops (stmt)) |
88dbf20f | 649 | return VARYING; |
650 | ||
75a70cf9 | 651 | /* Arrive here for more complex cases. */ |
bfa30570 | 652 | has_constant_operand = false; |
d61b9af3 | 653 | has_undefined_operand = false; |
654 | all_undefined_operands = true; | |
8edeb88b | 655 | FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE) |
41511585 | 656 | { |
bfa30570 | 657 | prop_value_t *val = get_value (use); |
41511585 | 658 | |
bfa30570 | 659 | if (val->lattice_val == UNDEFINED) |
d61b9af3 | 660 | has_undefined_operand = true; |
661 | else | |
662 | all_undefined_operands = false; | |
88dbf20f | 663 | |
41511585 | 664 | if (val->lattice_val == CONSTANT) |
bfa30570 | 665 | has_constant_operand = true; |
4ee9c684 | 666 | } |
41511585 | 667 | |
dd277d48 | 668 | /* There may be constants in regular rhs operands. For calls we |
669 | have to ignore lhs, fndecl and static chain, otherwise only | |
670 | the lhs. */ | |
671 | for (i = (is_gimple_call (stmt) ? 2 : 0) + gimple_has_lhs (stmt); | |
8edeb88b | 672 | i < gimple_num_ops (stmt); ++i) |
673 | { | |
674 | tree op = gimple_op (stmt, i); | |
675 | if (!op || TREE_CODE (op) == SSA_NAME) | |
676 | continue; | |
677 | if (is_gimple_min_invariant (op)) | |
678 | has_constant_operand = true; | |
679 | } | |
680 | ||
87c0a9fc | 681 | if (has_constant_operand) |
682 | all_undefined_operands = false; | |
683 | ||
d61b9af3 | 684 | /* If the operation combines operands like COMPLEX_EXPR make sure to |
685 | not mark the result UNDEFINED if only one part of the result is | |
686 | undefined. */ | |
75a70cf9 | 687 | if (has_undefined_operand && all_undefined_operands) |
d61b9af3 | 688 | return UNDEFINED; |
75a70cf9 | 689 | else if (code == GIMPLE_ASSIGN && has_undefined_operand) |
d61b9af3 | 690 | { |
75a70cf9 | 691 | switch (gimple_assign_rhs_code (stmt)) |
d61b9af3 | 692 | { |
693 | /* Unary operators are handled with all_undefined_operands. */ | |
694 | case PLUS_EXPR: | |
695 | case MINUS_EXPR: | |
d61b9af3 | 696 | case POINTER_PLUS_EXPR: |
d61b9af3 | 697 | /* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected. |
698 | Not bitwise operators, one VARYING operand may specify the | |
699 | result completely. Not logical operators for the same reason. | |
05a936a0 | 700 | Not COMPLEX_EXPR as one VARYING operand makes the result partly |
701 | not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because | |
702 | the undefined operand may be promoted. */ | |
d61b9af3 | 703 | return UNDEFINED; |
704 | ||
705 | default: | |
706 | ; | |
707 | } | |
708 | } | |
709 | /* If there was an UNDEFINED operand but the result may be not UNDEFINED | |
710 | fall back to VARYING even if there were CONSTANT operands. */ | |
711 | if (has_undefined_operand) | |
712 | return VARYING; | |
713 | ||
8edeb88b | 714 | /* We do not consider virtual operands here -- load from read-only |
715 | memory may have only VARYING virtual operands, but still be | |
716 | constant. */ | |
bfa30570 | 717 | if (has_constant_operand |
8edeb88b | 718 | || gimple_references_memory_p (stmt)) |
88dbf20f | 719 | return CONSTANT; |
720 | ||
bfa30570 | 721 | return VARYING; |
4ee9c684 | 722 | } |
723 | ||
bfa30570 | 724 | /* Returns true if STMT cannot be constant. */ |
725 | ||
726 | static bool | |
75a70cf9 | 727 | surely_varying_stmt_p (gimple stmt) |
bfa30570 | 728 | { |
729 | /* If the statement has operands that we cannot handle, it cannot be | |
730 | constant. */ | |
75a70cf9 | 731 | if (gimple_has_volatile_ops (stmt)) |
bfa30570 | 732 | return true; |
733 | ||
f257af64 | 734 | /* If it is a call and does not return a value or is not a |
735 | builtin and not an indirect call, it is varying. */ | |
75a70cf9 | 736 | if (is_gimple_call (stmt)) |
f257af64 | 737 | { |
738 | tree fndecl; | |
739 | if (!gimple_call_lhs (stmt) | |
740 | || ((fndecl = gimple_call_fndecl (stmt)) != NULL_TREE | |
5768aeb3 | 741 | && !DECL_BUILT_IN (fndecl))) |
f257af64 | 742 | return true; |
743 | } | |
bfa30570 | 744 | |
8edeb88b | 745 | /* Any other store operation is not interesting. */ |
dd277d48 | 746 | else if (gimple_vdef (stmt)) |
8edeb88b | 747 | return true; |
748 | ||
bfa30570 | 749 | /* Anything other than assignments and conditional jumps are not |
750 | interesting for CCP. */ | |
75a70cf9 | 751 | if (gimple_code (stmt) != GIMPLE_ASSIGN |
f257af64 | 752 | && gimple_code (stmt) != GIMPLE_COND |
753 | && gimple_code (stmt) != GIMPLE_SWITCH | |
754 | && gimple_code (stmt) != GIMPLE_CALL) | |
bfa30570 | 755 | return true; |
756 | ||
757 | return false; | |
758 | } | |
4ee9c684 | 759 | |
41511585 | 760 | /* Initialize local data structures for CCP. */ |
4ee9c684 | 761 | |
762 | static void | |
41511585 | 763 | ccp_initialize (void) |
4ee9c684 | 764 | { |
41511585 | 765 | basic_block bb; |
4ee9c684 | 766 | |
43959b95 | 767 | const_val = XCNEWVEC (prop_value_t, num_ssa_names); |
4ee9c684 | 768 | |
41511585 | 769 | /* Initialize simulation flags for PHI nodes and statements. */ |
770 | FOR_EACH_BB (bb) | |
4ee9c684 | 771 | { |
75a70cf9 | 772 | gimple_stmt_iterator i; |
4ee9c684 | 773 | |
75a70cf9 | 774 | for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) |
41511585 | 775 | { |
75a70cf9 | 776 | gimple stmt = gsi_stmt (i); |
2193544e | 777 | bool is_varying; |
778 | ||
779 | /* If the statement is a control insn, then we do not | |
780 | want to avoid simulating the statement once. Failure | |
781 | to do so means that those edges will never get added. */ | |
782 | if (stmt_ends_bb_p (stmt)) | |
783 | is_varying = false; | |
784 | else | |
785 | is_varying = surely_varying_stmt_p (stmt); | |
4ee9c684 | 786 | |
bfa30570 | 787 | if (is_varying) |
41511585 | 788 | { |
88dbf20f | 789 | tree def; |
790 | ssa_op_iter iter; | |
791 | ||
792 | /* If the statement will not produce a constant, mark | |
793 | all its outputs VARYING. */ | |
794 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) | |
8edeb88b | 795 | set_value_varying (def); |
41511585 | 796 | } |
75a70cf9 | 797 | prop_set_simulate_again (stmt, !is_varying); |
41511585 | 798 | } |
4ee9c684 | 799 | } |
800 | ||
75a70cf9 | 801 | /* Now process PHI nodes. We never clear the simulate_again flag on |
802 | phi nodes, since we do not know which edges are executable yet, | |
803 | except for phi nodes for virtual operands when we do not do store ccp. */ | |
41511585 | 804 | FOR_EACH_BB (bb) |
4ee9c684 | 805 | { |
75a70cf9 | 806 | gimple_stmt_iterator i; |
41511585 | 807 | |
75a70cf9 | 808 | for (i = gsi_start_phis (bb); !gsi_end_p (i); gsi_next (&i)) |
809 | { | |
810 | gimple phi = gsi_stmt (i); | |
811 | ||
61207d43 | 812 | if (!is_gimple_reg (gimple_phi_result (phi))) |
75a70cf9 | 813 | prop_set_simulate_again (phi, false); |
bfa30570 | 814 | else |
75a70cf9 | 815 | prop_set_simulate_again (phi, true); |
41511585 | 816 | } |
4ee9c684 | 817 | } |
41511585 | 818 | } |
4ee9c684 | 819 | |
43fb76c1 | 820 | /* Debug count support. Reset the values of ssa names |
821 | VARYING when the total number ssa names analyzed is | |
822 | beyond the debug count specified. */ | |
823 | ||
824 | static void | |
825 | do_dbg_cnt (void) | |
826 | { | |
827 | unsigned i; | |
828 | for (i = 0; i < num_ssa_names; i++) | |
829 | { | |
830 | if (!dbg_cnt (ccp)) | |
831 | { | |
832 | const_val[i].lattice_val = VARYING; | |
b7e55469 | 833 | const_val[i].mask = double_int_minus_one; |
43fb76c1 | 834 | const_val[i].value = NULL_TREE; |
835 | } | |
836 | } | |
837 | } | |
838 | ||
4ee9c684 | 839 | |
88dbf20f | 840 | /* Do final substitution of propagated values, cleanup the flowgraph and |
48e1416a | 841 | free allocated storage. |
4ee9c684 | 842 | |
33a34f1e | 843 | Return TRUE when something was optimized. */ |
844 | ||
845 | static bool | |
88dbf20f | 846 | ccp_finalize (void) |
4ee9c684 | 847 | { |
43fb76c1 | 848 | bool something_changed; |
153c3b50 | 849 | unsigned i; |
43fb76c1 | 850 | |
851 | do_dbg_cnt (); | |
153c3b50 | 852 | |
853 | /* Derive alignment and misalignment information from partially | |
854 | constant pointers in the lattice. */ | |
855 | for (i = 1; i < num_ssa_names; ++i) | |
856 | { | |
857 | tree name = ssa_name (i); | |
858 | prop_value_t *val; | |
859 | struct ptr_info_def *pi; | |
860 | unsigned int tem, align; | |
861 | ||
862 | if (!name | |
863 | || !POINTER_TYPE_P (TREE_TYPE (name))) | |
864 | continue; | |
865 | ||
866 | val = get_value (name); | |
867 | if (val->lattice_val != CONSTANT | |
868 | || TREE_CODE (val->value) != INTEGER_CST) | |
869 | continue; | |
870 | ||
871 | /* Trailing constant bits specify the alignment, trailing value | |
872 | bits the misalignment. */ | |
873 | tem = val->mask.low; | |
874 | align = (tem & -tem); | |
875 | if (align == 1) | |
876 | continue; | |
877 | ||
878 | pi = get_ptr_info (name); | |
879 | pi->align = align; | |
880 | pi->misalign = TREE_INT_CST_LOW (val->value) & (align - 1); | |
881 | } | |
882 | ||
88dbf20f | 883 | /* Perform substitutions based on the known constant values. */ |
14f101cf | 884 | something_changed = substitute_and_fold (get_constant_value, |
885 | ccp_fold_stmt, true); | |
4ee9c684 | 886 | |
88dbf20f | 887 | free (const_val); |
e004838d | 888 | const_val = NULL; |
33a34f1e | 889 | return something_changed;; |
4ee9c684 | 890 | } |
891 | ||
892 | ||
88dbf20f | 893 | /* Compute the meet operator between *VAL1 and *VAL2. Store the result |
894 | in VAL1. | |
895 | ||
896 | any M UNDEFINED = any | |
88dbf20f | 897 | any M VARYING = VARYING |
898 | Ci M Cj = Ci if (i == j) | |
899 | Ci M Cj = VARYING if (i != j) | |
bfa30570 | 900 | */ |
4ee9c684 | 901 | |
902 | static void | |
88dbf20f | 903 | ccp_lattice_meet (prop_value_t *val1, prop_value_t *val2) |
4ee9c684 | 904 | { |
88dbf20f | 905 | if (val1->lattice_val == UNDEFINED) |
4ee9c684 | 906 | { |
88dbf20f | 907 | /* UNDEFINED M any = any */ |
908 | *val1 = *val2; | |
41511585 | 909 | } |
88dbf20f | 910 | else if (val2->lattice_val == UNDEFINED) |
92481a4d | 911 | { |
88dbf20f | 912 | /* any M UNDEFINED = any |
913 | Nothing to do. VAL1 already contains the value we want. */ | |
914 | ; | |
92481a4d | 915 | } |
88dbf20f | 916 | else if (val1->lattice_val == VARYING |
917 | || val2->lattice_val == VARYING) | |
41511585 | 918 | { |
88dbf20f | 919 | /* any M VARYING = VARYING. */ |
920 | val1->lattice_val = VARYING; | |
b7e55469 | 921 | val1->mask = double_int_minus_one; |
88dbf20f | 922 | val1->value = NULL_TREE; |
41511585 | 923 | } |
b7e55469 | 924 | else if (val1->lattice_val == CONSTANT |
925 | && val2->lattice_val == CONSTANT | |
926 | && TREE_CODE (val1->value) == INTEGER_CST | |
927 | && TREE_CODE (val2->value) == INTEGER_CST) | |
928 | { | |
929 | /* Ci M Cj = Ci if (i == j) | |
930 | Ci M Cj = VARYING if (i != j) | |
931 | ||
932 | For INTEGER_CSTs mask unequal bits. If no equal bits remain, | |
933 | drop to varying. */ | |
934 | val1->mask | |
935 | = double_int_ior (double_int_ior (val1->mask, | |
936 | val2->mask), | |
937 | double_int_xor (tree_to_double_int (val1->value), | |
938 | tree_to_double_int (val2->value))); | |
939 | if (double_int_minus_one_p (val1->mask)) | |
940 | { | |
941 | val1->lattice_val = VARYING; | |
942 | val1->value = NULL_TREE; | |
943 | } | |
944 | } | |
88dbf20f | 945 | else if (val1->lattice_val == CONSTANT |
946 | && val2->lattice_val == CONSTANT | |
61207d43 | 947 | && simple_cst_equal (val1->value, val2->value) == 1) |
41511585 | 948 | { |
88dbf20f | 949 | /* Ci M Cj = Ci if (i == j) |
950 | Ci M Cj = VARYING if (i != j) | |
951 | ||
b7e55469 | 952 | VAL1 already contains the value we want for equivalent values. */ |
953 | } | |
954 | else if (val1->lattice_val == CONSTANT | |
955 | && val2->lattice_val == CONSTANT | |
956 | && (TREE_CODE (val1->value) == ADDR_EXPR | |
957 | || TREE_CODE (val2->value) == ADDR_EXPR)) | |
958 | { | |
959 | /* When not equal addresses are involved try meeting for | |
960 | alignment. */ | |
961 | prop_value_t tem = *val2; | |
962 | if (TREE_CODE (val1->value) == ADDR_EXPR) | |
963 | *val1 = get_value_for_expr (val1->value, true); | |
964 | if (TREE_CODE (val2->value) == ADDR_EXPR) | |
965 | tem = get_value_for_expr (val2->value, true); | |
966 | ccp_lattice_meet (val1, &tem); | |
41511585 | 967 | } |
968 | else | |
969 | { | |
88dbf20f | 970 | /* Any other combination is VARYING. */ |
971 | val1->lattice_val = VARYING; | |
b7e55469 | 972 | val1->mask = double_int_minus_one; |
88dbf20f | 973 | val1->value = NULL_TREE; |
41511585 | 974 | } |
4ee9c684 | 975 | } |
976 | ||
977 | ||
41511585 | 978 | /* Loop through the PHI_NODE's parameters for BLOCK and compare their |
979 | lattice values to determine PHI_NODE's lattice value. The value of a | |
88dbf20f | 980 | PHI node is determined calling ccp_lattice_meet with all the arguments |
41511585 | 981 | of the PHI node that are incoming via executable edges. */ |
4ee9c684 | 982 | |
41511585 | 983 | static enum ssa_prop_result |
75a70cf9 | 984 | ccp_visit_phi_node (gimple phi) |
4ee9c684 | 985 | { |
75a70cf9 | 986 | unsigned i; |
88dbf20f | 987 | prop_value_t *old_val, new_val; |
4ee9c684 | 988 | |
41511585 | 989 | if (dump_file && (dump_flags & TDF_DETAILS)) |
4ee9c684 | 990 | { |
41511585 | 991 | fprintf (dump_file, "\nVisiting PHI node: "); |
75a70cf9 | 992 | print_gimple_stmt (dump_file, phi, 0, dump_flags); |
4ee9c684 | 993 | } |
4ee9c684 | 994 | |
75a70cf9 | 995 | old_val = get_value (gimple_phi_result (phi)); |
41511585 | 996 | switch (old_val->lattice_val) |
997 | { | |
998 | case VARYING: | |
88dbf20f | 999 | return SSA_PROP_VARYING; |
4ee9c684 | 1000 | |
41511585 | 1001 | case CONSTANT: |
1002 | new_val = *old_val; | |
1003 | break; | |
4ee9c684 | 1004 | |
41511585 | 1005 | case UNDEFINED: |
41511585 | 1006 | new_val.lattice_val = UNDEFINED; |
88dbf20f | 1007 | new_val.value = NULL_TREE; |
41511585 | 1008 | break; |
4ee9c684 | 1009 | |
41511585 | 1010 | default: |
8c0963c4 | 1011 | gcc_unreachable (); |
41511585 | 1012 | } |
4ee9c684 | 1013 | |
75a70cf9 | 1014 | for (i = 0; i < gimple_phi_num_args (phi); i++) |
41511585 | 1015 | { |
88dbf20f | 1016 | /* Compute the meet operator over all the PHI arguments flowing |
1017 | through executable edges. */ | |
75a70cf9 | 1018 | edge e = gimple_phi_arg_edge (phi, i); |
4ee9c684 | 1019 | |
41511585 | 1020 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1021 | { | |
1022 | fprintf (dump_file, | |
1023 | "\n Argument #%d (%d -> %d %sexecutable)\n", | |
1024 | i, e->src->index, e->dest->index, | |
1025 | (e->flags & EDGE_EXECUTABLE) ? "" : "not "); | |
1026 | } | |
1027 | ||
1028 | /* If the incoming edge is executable, Compute the meet operator for | |
1029 | the existing value of the PHI node and the current PHI argument. */ | |
1030 | if (e->flags & EDGE_EXECUTABLE) | |
1031 | { | |
75a70cf9 | 1032 | tree arg = gimple_phi_arg (phi, i)->def; |
b7e55469 | 1033 | prop_value_t arg_val = get_value_for_expr (arg, false); |
4ee9c684 | 1034 | |
88dbf20f | 1035 | ccp_lattice_meet (&new_val, &arg_val); |
4ee9c684 | 1036 | |
41511585 | 1037 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1038 | { | |
1039 | fprintf (dump_file, "\t"); | |
88dbf20f | 1040 | print_generic_expr (dump_file, arg, dump_flags); |
1041 | dump_lattice_value (dump_file, "\tValue: ", arg_val); | |
41511585 | 1042 | fprintf (dump_file, "\n"); |
1043 | } | |
4ee9c684 | 1044 | |
41511585 | 1045 | if (new_val.lattice_val == VARYING) |
1046 | break; | |
1047 | } | |
1048 | } | |
4ee9c684 | 1049 | |
1050 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
41511585 | 1051 | { |
1052 | dump_lattice_value (dump_file, "\n PHI node value: ", new_val); | |
1053 | fprintf (dump_file, "\n\n"); | |
1054 | } | |
1055 | ||
bfa30570 | 1056 | /* Make the transition to the new value. */ |
75a70cf9 | 1057 | if (set_lattice_value (gimple_phi_result (phi), new_val)) |
41511585 | 1058 | { |
1059 | if (new_val.lattice_val == VARYING) | |
1060 | return SSA_PROP_VARYING; | |
1061 | else | |
1062 | return SSA_PROP_INTERESTING; | |
1063 | } | |
1064 | else | |
1065 | return SSA_PROP_NOT_INTERESTING; | |
4ee9c684 | 1066 | } |
1067 | ||
15d138c9 | 1068 | /* Return the constant value for OP or OP otherwise. */ |
00f4f705 | 1069 | |
1070 | static tree | |
15d138c9 | 1071 | valueize_op (tree op) |
00f4f705 | 1072 | { |
00f4f705 | 1073 | if (TREE_CODE (op) == SSA_NAME) |
1074 | { | |
15d138c9 | 1075 | tree tem = get_constant_value (op); |
1076 | if (tem) | |
1077 | return tem; | |
00f4f705 | 1078 | } |
1079 | return op; | |
1080 | } | |
1081 | ||
41511585 | 1082 | /* CCP specific front-end to the non-destructive constant folding |
1083 | routines. | |
4ee9c684 | 1084 | |
1085 | Attempt to simplify the RHS of STMT knowing that one or more | |
1086 | operands are constants. | |
1087 | ||
1088 | If simplification is possible, return the simplified RHS, | |
75a70cf9 | 1089 | otherwise return the original RHS or NULL_TREE. */ |
4ee9c684 | 1090 | |
1091 | static tree | |
75a70cf9 | 1092 | ccp_fold (gimple stmt) |
4ee9c684 | 1093 | { |
389dd41b | 1094 | location_t loc = gimple_location (stmt); |
75a70cf9 | 1095 | switch (gimple_code (stmt)) |
88dbf20f | 1096 | { |
75a70cf9 | 1097 | case GIMPLE_ASSIGN: |
1098 | { | |
1099 | enum tree_code subcode = gimple_assign_rhs_code (stmt); | |
1100 | ||
1101 | switch (get_gimple_rhs_class (subcode)) | |
1102 | { | |
1103 | case GIMPLE_SINGLE_RHS: | |
1104 | { | |
1105 | tree rhs = gimple_assign_rhs1 (stmt); | |
1106 | enum tree_code_class kind = TREE_CODE_CLASS (subcode); | |
1107 | ||
1108 | if (TREE_CODE (rhs) == SSA_NAME) | |
1109 | { | |
1110 | /* If the RHS is an SSA_NAME, return its known constant value, | |
1111 | if any. */ | |
15d138c9 | 1112 | return get_constant_value (rhs); |
75a70cf9 | 1113 | } |
1114 | /* Handle propagating invariant addresses into address operations. | |
1115 | The folding we do here matches that in tree-ssa-forwprop.c. */ | |
1116 | else if (TREE_CODE (rhs) == ADDR_EXPR) | |
1117 | { | |
1118 | tree *base; | |
1119 | base = &TREE_OPERAND (rhs, 0); | |
1120 | while (handled_component_p (*base)) | |
1121 | base = &TREE_OPERAND (*base, 0); | |
182cf5a9 | 1122 | if (TREE_CODE (*base) == MEM_REF |
75a70cf9 | 1123 | && TREE_CODE (TREE_OPERAND (*base, 0)) == SSA_NAME) |
1124 | { | |
15d138c9 | 1125 | tree val = get_constant_value (TREE_OPERAND (*base, 0)); |
1126 | if (val | |
1127 | && TREE_CODE (val) == ADDR_EXPR) | |
75a70cf9 | 1128 | { |
182cf5a9 | 1129 | tree ret, save = *base; |
1130 | tree new_base; | |
1131 | new_base = fold_build2 (MEM_REF, TREE_TYPE (*base), | |
15d138c9 | 1132 | unshare_expr (val), |
182cf5a9 | 1133 | TREE_OPERAND (*base, 1)); |
75a70cf9 | 1134 | /* We need to return a new tree, not modify the IL |
1135 | or share parts of it. So play some tricks to | |
1136 | avoid manually building it. */ | |
182cf5a9 | 1137 | *base = new_base; |
75a70cf9 | 1138 | ret = unshare_expr (rhs); |
1139 | recompute_tree_invariant_for_addr_expr (ret); | |
1140 | *base = save; | |
1141 | return ret; | |
1142 | } | |
1143 | } | |
1144 | } | |
388a0bc7 | 1145 | else if (TREE_CODE (rhs) == CONSTRUCTOR |
1146 | && TREE_CODE (TREE_TYPE (rhs)) == VECTOR_TYPE | |
1147 | && (CONSTRUCTOR_NELTS (rhs) | |
1148 | == TYPE_VECTOR_SUBPARTS (TREE_TYPE (rhs)))) | |
1149 | { | |
1150 | unsigned i; | |
1151 | tree val, list; | |
1152 | ||
1153 | list = NULL_TREE; | |
1154 | FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (rhs), i, val) | |
1155 | { | |
15d138c9 | 1156 | val = valueize_op (val); |
388a0bc7 | 1157 | if (TREE_CODE (val) == INTEGER_CST |
1158 | || TREE_CODE (val) == REAL_CST | |
1159 | || TREE_CODE (val) == FIXED_CST) | |
1160 | list = tree_cons (NULL_TREE, val, list); | |
1161 | else | |
1162 | return NULL_TREE; | |
1163 | } | |
1164 | ||
1165 | return build_vector (TREE_TYPE (rhs), nreverse (list)); | |
1166 | } | |
4ee9c684 | 1167 | |
75a70cf9 | 1168 | if (kind == tcc_reference) |
3e4be816 | 1169 | { |
0fefde02 | 1170 | if ((TREE_CODE (rhs) == VIEW_CONVERT_EXPR |
1171 | || TREE_CODE (rhs) == REALPART_EXPR | |
1172 | || TREE_CODE (rhs) == IMAGPART_EXPR) | |
3e4be816 | 1173 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME) |
1174 | { | |
15d138c9 | 1175 | tree val = get_constant_value (TREE_OPERAND (rhs, 0)); |
1176 | if (val) | |
389dd41b | 1177 | return fold_unary_loc (EXPR_LOCATION (rhs), |
15d138c9 | 1178 | TREE_CODE (rhs), |
1179 | TREE_TYPE (rhs), val); | |
3e4be816 | 1180 | } |
182cf5a9 | 1181 | else if (TREE_CODE (rhs) == MEM_REF |
8edeb88b | 1182 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME) |
1183 | { | |
15d138c9 | 1184 | tree val = get_constant_value (TREE_OPERAND (rhs, 0)); |
1185 | if (val | |
1186 | && TREE_CODE (val) == ADDR_EXPR) | |
182cf5a9 | 1187 | { |
1188 | tree tem = fold_build2 (MEM_REF, TREE_TYPE (rhs), | |
15d138c9 | 1189 | unshare_expr (val), |
182cf5a9 | 1190 | TREE_OPERAND (rhs, 1)); |
1191 | if (tem) | |
1192 | rhs = tem; | |
1193 | } | |
8edeb88b | 1194 | } |
3e4be816 | 1195 | return fold_const_aggregate_ref (rhs); |
1196 | } | |
75a70cf9 | 1197 | else if (kind == tcc_declaration) |
1198 | return get_symbol_constant_value (rhs); | |
1199 | return rhs; | |
1200 | } | |
48e1416a | 1201 | |
75a70cf9 | 1202 | case GIMPLE_UNARY_RHS: |
1203 | { | |
1204 | /* Handle unary operators that can appear in GIMPLE form. | |
1205 | Note that we know the single operand must be a constant, | |
1206 | so this should almost always return a simplified RHS. */ | |
1207 | tree lhs = gimple_assign_lhs (stmt); | |
15d138c9 | 1208 | tree op0 = valueize_op (gimple_assign_rhs1 (stmt)); |
75a70cf9 | 1209 | |
1210 | /* Conversions are useless for CCP purposes if they are | |
1211 | value-preserving. Thus the restrictions that | |
1212 | useless_type_conversion_p places for pointer type conversions | |
1213 | do not apply here. Substitution later will only substitute to | |
1214 | allowed places. */ | |
d9659041 | 1215 | if (CONVERT_EXPR_CODE_P (subcode) |
5768aeb3 | 1216 | && POINTER_TYPE_P (TREE_TYPE (lhs)) |
182cf5a9 | 1217 | && POINTER_TYPE_P (TREE_TYPE (op0))) |
5768aeb3 | 1218 | { |
1219 | tree tem; | |
182cf5a9 | 1220 | /* Try to re-construct array references on-the-fly. */ |
5768aeb3 | 1221 | if (!useless_type_conversion_p (TREE_TYPE (lhs), |
1222 | TREE_TYPE (op0)) | |
1223 | && ((tem = maybe_fold_offset_to_address | |
389dd41b | 1224 | (loc, |
e60a6f7b | 1225 | op0, integer_zero_node, TREE_TYPE (lhs))) |
5768aeb3 | 1226 | != NULL_TREE)) |
1227 | return tem; | |
1228 | return op0; | |
1229 | } | |
75a70cf9 | 1230 | |
48e1416a | 1231 | return |
389dd41b | 1232 | fold_unary_ignore_overflow_loc (loc, subcode, |
1233 | gimple_expr_type (stmt), op0); | |
f1fb2997 | 1234 | } |
75a70cf9 | 1235 | |
1236 | case GIMPLE_BINARY_RHS: | |
1237 | { | |
1238 | /* Handle binary operators that can appear in GIMPLE form. */ | |
15d138c9 | 1239 | tree op0 = valueize_op (gimple_assign_rhs1 (stmt)); |
1240 | tree op1 = valueize_op (gimple_assign_rhs2 (stmt)); | |
75a70cf9 | 1241 | |
182cf5a9 | 1242 | /* Translate &x + CST into an invariant form suitable for |
1243 | further propagation. */ | |
5768aeb3 | 1244 | if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR |
1245 | && TREE_CODE (op0) == ADDR_EXPR | |
1246 | && TREE_CODE (op1) == INTEGER_CST) | |
1247 | { | |
182cf5a9 | 1248 | tree off = fold_convert (ptr_type_node, op1); |
1249 | return build_fold_addr_expr | |
1250 | (fold_build2 (MEM_REF, | |
1251 | TREE_TYPE (TREE_TYPE (op0)), | |
1252 | unshare_expr (op0), off)); | |
5768aeb3 | 1253 | } |
1254 | ||
389dd41b | 1255 | return fold_binary_loc (loc, subcode, |
182cf5a9 | 1256 | gimple_expr_type (stmt), op0, op1); |
75a70cf9 | 1257 | } |
1258 | ||
00f4f705 | 1259 | case GIMPLE_TERNARY_RHS: |
1260 | { | |
15d138c9 | 1261 | /* Handle ternary operators that can appear in GIMPLE form. */ |
1262 | tree op0 = valueize_op (gimple_assign_rhs1 (stmt)); | |
1263 | tree op1 = valueize_op (gimple_assign_rhs2 (stmt)); | |
1264 | tree op2 = valueize_op (gimple_assign_rhs3 (stmt)); | |
00f4f705 | 1265 | |
1266 | return fold_ternary_loc (loc, subcode, | |
1267 | gimple_expr_type (stmt), op0, op1, op2); | |
1268 | } | |
1269 | ||
75a70cf9 | 1270 | default: |
1271 | gcc_unreachable (); | |
1272 | } | |
1273 | } | |
1274 | break; | |
4ee9c684 | 1275 | |
75a70cf9 | 1276 | case GIMPLE_CALL: |
f257af64 | 1277 | { |
15d138c9 | 1278 | tree fn = valueize_op (gimple_call_fn (stmt)); |
f257af64 | 1279 | if (TREE_CODE (fn) == ADDR_EXPR |
8ef4f124 | 1280 | && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL |
f257af64 | 1281 | && DECL_BUILT_IN (TREE_OPERAND (fn, 0))) |
1282 | { | |
1283 | tree *args = XALLOCAVEC (tree, gimple_call_num_args (stmt)); | |
1284 | tree call, retval; | |
1285 | unsigned i; | |
1286 | for (i = 0; i < gimple_call_num_args (stmt); ++i) | |
15d138c9 | 1287 | args[i] = valueize_op (gimple_call_arg (stmt, i)); |
389dd41b | 1288 | call = build_call_array_loc (loc, |
1289 | gimple_call_return_type (stmt), | |
1290 | fn, gimple_call_num_args (stmt), args); | |
1291 | retval = fold_call_expr (EXPR_LOCATION (call), call, false); | |
f257af64 | 1292 | if (retval) |
1293 | /* fold_call_expr wraps the result inside a NOP_EXPR. */ | |
1294 | STRIP_NOPS (retval); | |
1295 | return retval; | |
1296 | } | |
1297 | return NULL_TREE; | |
1298 | } | |
4ee9c684 | 1299 | |
75a70cf9 | 1300 | case GIMPLE_COND: |
1301 | { | |
1302 | /* Handle comparison operators that can appear in GIMPLE form. */ | |
15d138c9 | 1303 | tree op0 = valueize_op (gimple_cond_lhs (stmt)); |
1304 | tree op1 = valueize_op (gimple_cond_rhs (stmt)); | |
75a70cf9 | 1305 | enum tree_code code = gimple_cond_code (stmt); |
389dd41b | 1306 | return fold_binary_loc (loc, code, boolean_type_node, op0, op1); |
75a70cf9 | 1307 | } |
4ee9c684 | 1308 | |
75a70cf9 | 1309 | case GIMPLE_SWITCH: |
1310 | { | |
15d138c9 | 1311 | /* Return the constant switch index. */ |
1312 | return valueize_op (gimple_switch_index (stmt)); | |
75a70cf9 | 1313 | } |
912f109f | 1314 | |
75a70cf9 | 1315 | default: |
1316 | gcc_unreachable (); | |
4ee9c684 | 1317 | } |
4ee9c684 | 1318 | } |
1319 | ||
98d92e3c | 1320 | /* See if we can find constructor defining value of BASE. |
4912473d | 1321 | When we know the consructor with constant offset (such as |
1322 | base is array[40] and we do know constructor of array), then | |
1323 | BIT_OFFSET is adjusted accordingly. | |
98d92e3c | 1324 | |
1325 | As a special case, return error_mark_node when constructor | |
1326 | is not explicitly available, but it is known to be zero | |
1327 | such as 'static const int a;'. */ | |
1328 | static tree | |
4912473d | 1329 | get_base_constructor (tree base, HOST_WIDE_INT *bit_offset) |
98d92e3c | 1330 | { |
4912473d | 1331 | HOST_WIDE_INT bit_offset2, size, max_size; |
98d92e3c | 1332 | if (TREE_CODE (base) == MEM_REF) |
1333 | { | |
1334 | if (!integer_zerop (TREE_OPERAND (base, 1))) | |
4912473d | 1335 | { |
1336 | if (!host_integerp (TREE_OPERAND (base, 1), 0)) | |
1337 | return NULL_TREE; | |
1338 | *bit_offset += (mem_ref_offset (base).low | |
1339 | * BITS_PER_UNIT); | |
1340 | } | |
98d92e3c | 1341 | |
1342 | base = get_constant_value (TREE_OPERAND (base, 0)); | |
1343 | if (!base || TREE_CODE (base) != ADDR_EXPR) | |
1344 | return NULL_TREE; | |
1345 | base = TREE_OPERAND (base, 0); | |
1346 | } | |
1347 | ||
1348 | /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its | |
1349 | DECL_INITIAL. If BASE is a nested reference into another | |
1350 | ARRAY_REF or COMPONENT_REF, make a recursive call to resolve | |
1351 | the inner reference. */ | |
1352 | switch (TREE_CODE (base)) | |
1353 | { | |
1354 | case VAR_DECL: | |
7ae8b539 | 1355 | if (!const_value_known_p (base)) |
98d92e3c | 1356 | return NULL_TREE; |
1357 | ||
1358 | /* Fallthru. */ | |
1359 | case CONST_DECL: | |
1360 | if (!DECL_INITIAL (base) | |
1361 | && (TREE_STATIC (base) || DECL_EXTERNAL (base))) | |
1362 | return error_mark_node; | |
1363 | return DECL_INITIAL (base); | |
98d92e3c | 1364 | |
1365 | case ARRAY_REF: | |
1366 | case COMPONENT_REF: | |
4912473d | 1367 | base = get_ref_base_and_extent (base, &bit_offset2, &size, &max_size); |
1368 | if (max_size == -1 || size != max_size) | |
1369 | return NULL_TREE; | |
1370 | *bit_offset += bit_offset2; | |
1371 | return get_base_constructor (base, bit_offset); | |
98d92e3c | 1372 | |
1373 | case STRING_CST: | |
1374 | case CONSTRUCTOR: | |
1375 | return base; | |
98d92e3c | 1376 | |
1377 | default: | |
1378 | return NULL_TREE; | |
1379 | } | |
1380 | } | |
1381 | ||
83f4b93b | 1382 | /* CTOR is STRING_CST. Fold reference of type TYPE and size SIZE |
1383 | to the memory at bit OFFSET. | |
1384 | ||
1385 | We do only simple job of folding byte accesses. */ | |
1386 | ||
1387 | static tree | |
1388 | fold_string_cst_ctor_reference (tree type, tree ctor, unsigned HOST_WIDE_INT offset, | |
1389 | unsigned HOST_WIDE_INT size) | |
1390 | { | |
1391 | if (INTEGRAL_TYPE_P (type) | |
1392 | && (TYPE_MODE (type) | |
1393 | == TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1394 | && (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1395 | == MODE_INT) | |
1396 | && GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) == 1 | |
1397 | && size == BITS_PER_UNIT | |
1398 | && !(offset % BITS_PER_UNIT)) | |
1399 | { | |
1400 | offset /= BITS_PER_UNIT; | |
1401 | if (offset < (unsigned HOST_WIDE_INT) TREE_STRING_LENGTH (ctor)) | |
1402 | return build_int_cst_type (type, (TREE_STRING_POINTER (ctor) | |
1403 | [offset])); | |
1404 | /* Folding | |
1405 | const char a[20]="hello"; | |
1406 | return a[10]; | |
1407 | ||
1408 | might lead to offset greater than string length. In this case we | |
1409 | know value is either initialized to 0 or out of bounds. Return 0 | |
1410 | in both cases. */ | |
1411 | return build_zero_cst (type); | |
1412 | } | |
1413 | return NULL_TREE; | |
1414 | } | |
1415 | ||
1416 | /* CTOR is CONSTRUCTOR of an array type. Fold reference of type TYPE and size | |
1417 | SIZE to the memory at bit OFFSET. */ | |
1418 | ||
1419 | static tree | |
1420 | fold_array_ctor_reference (tree type, tree ctor, | |
1421 | unsigned HOST_WIDE_INT offset, | |
1422 | unsigned HOST_WIDE_INT size) | |
1423 | { | |
1424 | unsigned HOST_WIDE_INT cnt; | |
1425 | tree cfield, cval; | |
1426 | double_int low_bound, elt_size; | |
1427 | double_int index, max_index; | |
1428 | double_int access_index; | |
1429 | tree domain_type = TYPE_DOMAIN (TREE_TYPE (ctor)); | |
1430 | HOST_WIDE_INT inner_offset; | |
1431 | ||
1432 | /* Compute low bound and elt size. */ | |
1433 | if (domain_type && TYPE_MIN_VALUE (domain_type)) | |
1434 | { | |
1435 | /* Static constructors for variably sized objects makes no sense. */ | |
1436 | gcc_assert (TREE_CODE (TYPE_MIN_VALUE (domain_type)) == INTEGER_CST); | |
1437 | low_bound = tree_to_double_int (TYPE_MIN_VALUE (domain_type)); | |
1438 | } | |
1439 | else | |
1440 | low_bound = double_int_zero; | |
1441 | /* Static constructors for variably sized objects makes no sense. */ | |
1442 | gcc_assert (TREE_CODE(TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (ctor)))) | |
1443 | == INTEGER_CST); | |
1444 | elt_size = | |
1445 | tree_to_double_int (TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (ctor)))); | |
1446 | ||
1447 | ||
1448 | /* We can handle only constantly sized accesses that are known to not | |
1449 | be larger than size of array element. */ | |
1450 | if (!TYPE_SIZE_UNIT (type) | |
1451 | || TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST | |
1452 | || double_int_cmp (elt_size, | |
1453 | tree_to_double_int (TYPE_SIZE_UNIT (type)), 0) < 0) | |
1454 | return NULL_TREE; | |
1455 | ||
1456 | /* Compute the array index we look for. */ | |
1457 | access_index = double_int_udiv (uhwi_to_double_int (offset / BITS_PER_UNIT), | |
1458 | elt_size, TRUNC_DIV_EXPR); | |
1459 | access_index = double_int_add (access_index, low_bound); | |
1460 | ||
1461 | /* And offset within the access. */ | |
1462 | inner_offset = offset % (double_int_to_uhwi (elt_size) * BITS_PER_UNIT); | |
1463 | ||
1464 | /* See if the array field is large enough to span whole access. We do not | |
1465 | care to fold accesses spanning multiple array indexes. */ | |
1466 | if (inner_offset + size > double_int_to_uhwi (elt_size) * BITS_PER_UNIT) | |
1467 | return NULL_TREE; | |
1468 | ||
1469 | index = double_int_sub (low_bound, double_int_one); | |
1470 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) | |
1471 | { | |
1472 | /* Array constructor might explicitely set index, or specify range | |
1473 | or leave index NULL meaning that it is next index after previous | |
1474 | one. */ | |
1475 | if (cfield) | |
1476 | { | |
1477 | if (TREE_CODE (cfield) == INTEGER_CST) | |
1478 | max_index = index = tree_to_double_int (cfield); | |
1479 | else | |
1480 | { | |
1481 | gcc_assert (TREE_CODE (cfield) == RANGE_EXPR); | |
1482 | index = tree_to_double_int (TREE_OPERAND (cfield, 0)); | |
1483 | max_index = tree_to_double_int (TREE_OPERAND (cfield, 1)); | |
1484 | } | |
1485 | } | |
1486 | else | |
1487 | max_index = index = double_int_add (index, double_int_one); | |
1488 | ||
1489 | /* Do we have match? */ | |
1490 | if (double_int_cmp (access_index, index, 1) >= 0 | |
1491 | && double_int_cmp (access_index, max_index, 1) <= 0) | |
1492 | return fold_ctor_reference (type, cval, inner_offset, size); | |
1493 | } | |
1494 | /* When memory is not explicitely mentioned in constructor, | |
1495 | it is 0 (or out of range). */ | |
1496 | return build_zero_cst (type); | |
1497 | } | |
1498 | ||
1499 | /* CTOR is CONSTRUCTOR of an aggregate or vector. | |
1500 | Fold reference of type TYPE and size SIZE to the memory at bit OFFSET. */ | |
1501 | ||
1502 | static tree | |
1503 | fold_nonarray_ctor_reference (tree type, tree ctor, | |
1504 | unsigned HOST_WIDE_INT offset, | |
1505 | unsigned HOST_WIDE_INT size) | |
1506 | { | |
1507 | unsigned HOST_WIDE_INT cnt; | |
1508 | tree cfield, cval; | |
1509 | ||
1510 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, | |
1511 | cval) | |
1512 | { | |
1513 | tree byte_offset = DECL_FIELD_OFFSET (cfield); | |
1514 | tree field_offset = DECL_FIELD_BIT_OFFSET (cfield); | |
1515 | tree field_size = DECL_SIZE (cfield); | |
1516 | double_int bitoffset; | |
1517 | double_int byte_offset_cst = tree_to_double_int (byte_offset); | |
1518 | double_int bits_per_unit_cst = uhwi_to_double_int (BITS_PER_UNIT); | |
1519 | double_int bitoffset_end; | |
1520 | ||
4938e520 | 1521 | /* Variable sized objects in static constructors makes no sense, |
1522 | but field_size can be NULL for flexible array members. */ | |
83f4b93b | 1523 | gcc_assert (TREE_CODE (field_offset) == INTEGER_CST |
1524 | && TREE_CODE (byte_offset) == INTEGER_CST | |
4938e520 | 1525 | && (field_size != NULL_TREE |
1526 | ? TREE_CODE (field_size) == INTEGER_CST | |
1527 | : TREE_CODE (TREE_TYPE (cfield)) == ARRAY_TYPE)); | |
83f4b93b | 1528 | |
1529 | /* Compute bit offset of the field. */ | |
1530 | bitoffset = double_int_add (tree_to_double_int (field_offset), | |
1531 | double_int_mul (byte_offset_cst, | |
1532 | bits_per_unit_cst)); | |
1533 | /* Compute bit offset where the field ends. */ | |
4938e520 | 1534 | if (field_size != NULL_TREE) |
1535 | bitoffset_end = double_int_add (bitoffset, | |
1536 | tree_to_double_int (field_size)); | |
1537 | else | |
1538 | bitoffset_end = double_int_zero; | |
83f4b93b | 1539 | |
1540 | /* Is OFFSET in the range (BITOFFSET, BITOFFSET_END)? */ | |
1541 | if (double_int_cmp (uhwi_to_double_int (offset), bitoffset, 0) >= 0 | |
4938e520 | 1542 | && (field_size == NULL_TREE |
1543 | || double_int_cmp (uhwi_to_double_int (offset), | |
1544 | bitoffset_end, 0) < 0)) | |
83f4b93b | 1545 | { |
1546 | double_int access_end = double_int_add (uhwi_to_double_int (offset), | |
1547 | uhwi_to_double_int (size)); | |
1548 | double_int inner_offset = double_int_sub (uhwi_to_double_int (offset), | |
1549 | bitoffset); | |
1550 | /* We do have overlap. Now see if field is large enough to | |
1551 | cover the access. Give up for accesses spanning multiple | |
1552 | fields. */ | |
1553 | if (double_int_cmp (access_end, bitoffset_end, 0) > 0) | |
1554 | return NULL_TREE; | |
1555 | return fold_ctor_reference (type, cval, | |
1556 | double_int_to_uhwi (inner_offset), size); | |
1557 | } | |
1558 | } | |
1559 | /* When memory is not explicitely mentioned in constructor, it is 0. */ | |
1560 | return build_zero_cst (type); | |
1561 | } | |
1562 | ||
1563 | /* CTOR is value initializing memory, fold reference of type TYPE and size SIZE | |
1564 | to the memory at bit OFFSET. */ | |
1565 | ||
1566 | static tree | |
1567 | fold_ctor_reference (tree type, tree ctor, unsigned HOST_WIDE_INT offset, | |
1568 | unsigned HOST_WIDE_INT size) | |
1569 | { | |
1570 | tree ret; | |
1571 | ||
1572 | /* We found the field with exact match. */ | |
1573 | if (useless_type_conversion_p (type, TREE_TYPE (ctor)) | |
1574 | && !offset) | |
1575 | return canonicalize_constructor_val (ctor); | |
1576 | ||
1577 | /* We are at the end of walk, see if we can view convert the | |
1578 | result. */ | |
1579 | if (!AGGREGATE_TYPE_P (TREE_TYPE (ctor)) && !offset | |
1580 | /* VIEW_CONVERT_EXPR is defined only for matching sizes. */ | |
1581 | && operand_equal_p (TYPE_SIZE (type), | |
1582 | TYPE_SIZE (TREE_TYPE (ctor)), 0)) | |
1583 | { | |
1584 | ret = canonicalize_constructor_val (ctor); | |
1585 | ret = fold_unary (VIEW_CONVERT_EXPR, type, ret); | |
1586 | if (ret) | |
1587 | STRIP_NOPS (ret); | |
1588 | return ret; | |
1589 | } | |
1590 | if (TREE_CODE (ctor) == STRING_CST) | |
1591 | return fold_string_cst_ctor_reference (type, ctor, offset, size); | |
1592 | if (TREE_CODE (ctor) == CONSTRUCTOR) | |
1593 | { | |
1594 | ||
1595 | if (TREE_CODE (TREE_TYPE (ctor)) == ARRAY_TYPE) | |
1596 | return fold_array_ctor_reference (type, ctor, offset, size); | |
1597 | else | |
1598 | return fold_nonarray_ctor_reference (type, ctor, offset, size); | |
1599 | } | |
1600 | ||
1601 | return NULL_TREE; | |
1602 | } | |
1603 | ||
8782adcf | 1604 | /* Return the tree representing the element referenced by T if T is an |
1605 | ARRAY_REF or COMPONENT_REF into constant aggregates. Return | |
1606 | NULL_TREE otherwise. */ | |
1607 | ||
e004838d | 1608 | tree |
8782adcf | 1609 | fold_const_aggregate_ref (tree t) |
1610 | { | |
83f4b93b | 1611 | tree ctor, idx, base; |
1612 | HOST_WIDE_INT offset, size, max_size; | |
15d138c9 | 1613 | tree tem; |
8782adcf | 1614 | |
8edeb88b | 1615 | if (TREE_CODE_CLASS (TREE_CODE (t)) == tcc_declaration) |
1616 | return get_symbol_constant_value (t); | |
1617 | ||
15ba153a | 1618 | tem = fold_read_from_constant_string (t); |
1619 | if (tem) | |
1620 | return tem; | |
1621 | ||
8782adcf | 1622 | switch (TREE_CODE (t)) |
1623 | { | |
1624 | case ARRAY_REF: | |
83f4b93b | 1625 | case ARRAY_RANGE_REF: |
1626 | /* Constant indexes are handled well by get_base_constructor. | |
1627 | Only special case variable offsets. | |
1628 | FIXME: This code can't handle nested references with variable indexes | |
1629 | (they will be handled only by iteration of ccp). Perhaps we can bring | |
1630 | get_ref_base_and_extent here and make it use get_constant_value. */ | |
1631 | if (TREE_CODE (TREE_OPERAND (t, 1)) == SSA_NAME | |
1632 | && (idx = get_constant_value (TREE_OPERAND (t, 1))) | |
1633 | && host_integerp (idx, 0)) | |
1634 | { | |
1635 | tree low_bound, unit_size; | |
8782adcf | 1636 | |
83f4b93b | 1637 | /* If the resulting bit-offset is constant, track it. */ |
1638 | if ((low_bound = array_ref_low_bound (t), | |
1639 | host_integerp (low_bound, 0)) | |
1640 | && (unit_size = array_ref_element_size (t), | |
1641 | host_integerp (unit_size, 1))) | |
1642 | { | |
1643 | offset = TREE_INT_CST_LOW (idx); | |
1644 | offset -= TREE_INT_CST_LOW (low_bound); | |
1645 | offset *= TREE_INT_CST_LOW (unit_size); | |
1646 | offset *= BITS_PER_UNIT; | |
1647 | ||
1648 | base = TREE_OPERAND (t, 0); | |
4912473d | 1649 | ctor = get_base_constructor (base, &offset); |
83f4b93b | 1650 | /* Empty constructor. Always fold to 0. */ |
1651 | if (ctor == error_mark_node) | |
1652 | return build_zero_cst (TREE_TYPE (t)); | |
1653 | /* Out of bound array access. Value is undefined, but don't fold. */ | |
1654 | if (offset < 0) | |
1655 | return NULL_TREE; | |
1656 | /* We can not determine ctor. */ | |
1657 | if (!ctor) | |
1658 | return NULL_TREE; | |
1659 | return fold_ctor_reference (TREE_TYPE (t), ctor, offset, | |
1660 | TREE_INT_CST_LOW (unit_size) | |
1661 | * BITS_PER_UNIT); | |
1662 | } | |
1663 | } | |
1664 | /* Fallthru. */ | |
1665 | ||
1666 | case COMPONENT_REF: | |
1667 | case BIT_FIELD_REF: | |
1668 | case TARGET_MEM_REF: | |
1669 | case MEM_REF: | |
1670 | base = get_ref_base_and_extent (t, &offset, &size, &max_size); | |
4912473d | 1671 | ctor = get_base_constructor (base, &offset); |
04236c3a | 1672 | |
83f4b93b | 1673 | /* Empty constructor. Always fold to 0. */ |
98d92e3c | 1674 | if (ctor == error_mark_node) |
1675 | return build_zero_cst (TREE_TYPE (t)); | |
83f4b93b | 1676 | /* We do not know precise address. */ |
1677 | if (max_size == -1 || max_size != size) | |
1678 | return NULL_TREE; | |
1679 | /* We can not determine ctor. */ | |
1680 | if (!ctor) | |
8782adcf | 1681 | return NULL_TREE; |
1682 | ||
83f4b93b | 1683 | /* Out of bound array access. Value is undefined, but don't fold. */ |
1684 | if (offset < 0) | |
98d92e3c | 1685 | return NULL_TREE; |
8782adcf | 1686 | |
83f4b93b | 1687 | return fold_ctor_reference (TREE_TYPE (t), ctor, offset, size); |
8782adcf | 1688 | |
908cb59d | 1689 | case REALPART_EXPR: |
1690 | case IMAGPART_EXPR: | |
1691 | { | |
1692 | tree c = fold_const_aggregate_ref (TREE_OPERAND (t, 0)); | |
1693 | if (c && TREE_CODE (c) == COMPLEX_CST) | |
389dd41b | 1694 | return fold_build1_loc (EXPR_LOCATION (t), |
1695 | TREE_CODE (t), TREE_TYPE (t), c); | |
908cb59d | 1696 | break; |
1697 | } | |
04236c3a | 1698 | |
8782adcf | 1699 | default: |
1700 | break; | |
1701 | } | |
1702 | ||
1703 | return NULL_TREE; | |
1704 | } | |
75a70cf9 | 1705 | |
b7e55469 | 1706 | /* Apply the operation CODE in type TYPE to the value, mask pair |
1707 | RVAL and RMASK representing a value of type RTYPE and set | |
1708 | the value, mask pair *VAL and *MASK to the result. */ | |
1709 | ||
1710 | static void | |
1711 | bit_value_unop_1 (enum tree_code code, tree type, | |
1712 | double_int *val, double_int *mask, | |
1713 | tree rtype, double_int rval, double_int rmask) | |
1714 | { | |
1715 | switch (code) | |
1716 | { | |
1717 | case BIT_NOT_EXPR: | |
1718 | *mask = rmask; | |
1719 | *val = double_int_not (rval); | |
1720 | break; | |
1721 | ||
1722 | case NEGATE_EXPR: | |
1723 | { | |
1724 | double_int temv, temm; | |
1725 | /* Return ~rval + 1. */ | |
1726 | bit_value_unop_1 (BIT_NOT_EXPR, type, &temv, &temm, type, rval, rmask); | |
1727 | bit_value_binop_1 (PLUS_EXPR, type, val, mask, | |
1728 | type, temv, temm, | |
1729 | type, double_int_one, double_int_zero); | |
1730 | break; | |
1731 | } | |
1732 | ||
1733 | CASE_CONVERT: | |
1734 | { | |
1735 | bool uns; | |
1736 | ||
1737 | /* First extend mask and value according to the original type. */ | |
1738 | uns = (TREE_CODE (rtype) == INTEGER_TYPE && TYPE_IS_SIZETYPE (rtype) | |
1739 | ? 0 : TYPE_UNSIGNED (rtype)); | |
1740 | *mask = double_int_ext (rmask, TYPE_PRECISION (rtype), uns); | |
1741 | *val = double_int_ext (rval, TYPE_PRECISION (rtype), uns); | |
1742 | ||
1743 | /* Then extend mask and value according to the target type. */ | |
1744 | uns = (TREE_CODE (type) == INTEGER_TYPE && TYPE_IS_SIZETYPE (type) | |
1745 | ? 0 : TYPE_UNSIGNED (type)); | |
1746 | *mask = double_int_ext (*mask, TYPE_PRECISION (type), uns); | |
1747 | *val = double_int_ext (*val, TYPE_PRECISION (type), uns); | |
1748 | break; | |
1749 | } | |
1750 | ||
1751 | default: | |
1752 | *mask = double_int_minus_one; | |
1753 | break; | |
1754 | } | |
1755 | } | |
1756 | ||
1757 | /* Apply the operation CODE in type TYPE to the value, mask pairs | |
1758 | R1VAL, R1MASK and R2VAL, R2MASK representing a values of type R1TYPE | |
1759 | and R2TYPE and set the value, mask pair *VAL and *MASK to the result. */ | |
1760 | ||
1761 | static void | |
1762 | bit_value_binop_1 (enum tree_code code, tree type, | |
1763 | double_int *val, double_int *mask, | |
1764 | tree r1type, double_int r1val, double_int r1mask, | |
1765 | tree r2type, double_int r2val, double_int r2mask) | |
1766 | { | |
1767 | bool uns = (TREE_CODE (type) == INTEGER_TYPE | |
1768 | && TYPE_IS_SIZETYPE (type) ? 0 : TYPE_UNSIGNED (type)); | |
1769 | /* Assume we'll get a constant result. Use an initial varying value, | |
1770 | we fall back to varying in the end if necessary. */ | |
1771 | *mask = double_int_minus_one; | |
1772 | switch (code) | |
1773 | { | |
1774 | case BIT_AND_EXPR: | |
1775 | /* The mask is constant where there is a known not | |
1776 | set bit, (m1 | m2) & ((v1 | m1) & (v2 | m2)) */ | |
1777 | *mask = double_int_and (double_int_ior (r1mask, r2mask), | |
1778 | double_int_and (double_int_ior (r1val, r1mask), | |
1779 | double_int_ior (r2val, r2mask))); | |
1780 | *val = double_int_and (r1val, r2val); | |
1781 | break; | |
1782 | ||
1783 | case BIT_IOR_EXPR: | |
1784 | /* The mask is constant where there is a known | |
1785 | set bit, (m1 | m2) & ~((v1 & ~m1) | (v2 & ~m2)). */ | |
1786 | *mask = double_int_and_not | |
1787 | (double_int_ior (r1mask, r2mask), | |
1788 | double_int_ior (double_int_and_not (r1val, r1mask), | |
1789 | double_int_and_not (r2val, r2mask))); | |
1790 | *val = double_int_ior (r1val, r2val); | |
1791 | break; | |
1792 | ||
1793 | case BIT_XOR_EXPR: | |
1794 | /* m1 | m2 */ | |
1795 | *mask = double_int_ior (r1mask, r2mask); | |
1796 | *val = double_int_xor (r1val, r2val); | |
1797 | break; | |
1798 | ||
1799 | case LROTATE_EXPR: | |
1800 | case RROTATE_EXPR: | |
1801 | if (double_int_zero_p (r2mask)) | |
1802 | { | |
1803 | HOST_WIDE_INT shift = r2val.low; | |
1804 | if (code == RROTATE_EXPR) | |
1805 | shift = -shift; | |
1806 | *mask = double_int_lrotate (r1mask, shift, TYPE_PRECISION (type)); | |
1807 | *val = double_int_lrotate (r1val, shift, TYPE_PRECISION (type)); | |
1808 | } | |
1809 | break; | |
1810 | ||
1811 | case LSHIFT_EXPR: | |
1812 | case RSHIFT_EXPR: | |
1813 | /* ??? We can handle partially known shift counts if we know | |
1814 | its sign. That way we can tell that (x << (y | 8)) & 255 | |
1815 | is zero. */ | |
1816 | if (double_int_zero_p (r2mask)) | |
1817 | { | |
1818 | HOST_WIDE_INT shift = r2val.low; | |
1819 | if (code == RSHIFT_EXPR) | |
1820 | shift = -shift; | |
1821 | /* We need to know if we are doing a left or a right shift | |
1822 | to properly shift in zeros for left shift and unsigned | |
1823 | right shifts and the sign bit for signed right shifts. | |
1824 | For signed right shifts we shift in varying in case | |
1825 | the sign bit was varying. */ | |
1826 | if (shift > 0) | |
1827 | { | |
1828 | *mask = double_int_lshift (r1mask, shift, | |
1829 | TYPE_PRECISION (type), false); | |
1830 | *val = double_int_lshift (r1val, shift, | |
1831 | TYPE_PRECISION (type), false); | |
1832 | } | |
1833 | else if (shift < 0) | |
1834 | { | |
1835 | shift = -shift; | |
1836 | *mask = double_int_rshift (r1mask, shift, | |
1837 | TYPE_PRECISION (type), !uns); | |
1838 | *val = double_int_rshift (r1val, shift, | |
1839 | TYPE_PRECISION (type), !uns); | |
1840 | } | |
1841 | else | |
1842 | { | |
1843 | *mask = r1mask; | |
1844 | *val = r1val; | |
1845 | } | |
1846 | } | |
1847 | break; | |
1848 | ||
1849 | case PLUS_EXPR: | |
1850 | case POINTER_PLUS_EXPR: | |
1851 | { | |
1852 | double_int lo, hi; | |
1853 | /* Do the addition with unknown bits set to zero, to give carry-ins of | |
1854 | zero wherever possible. */ | |
1855 | lo = double_int_add (double_int_and_not (r1val, r1mask), | |
1856 | double_int_and_not (r2val, r2mask)); | |
1857 | lo = double_int_ext (lo, TYPE_PRECISION (type), uns); | |
1858 | /* Do the addition with unknown bits set to one, to give carry-ins of | |
1859 | one wherever possible. */ | |
1860 | hi = double_int_add (double_int_ior (r1val, r1mask), | |
1861 | double_int_ior (r2val, r2mask)); | |
1862 | hi = double_int_ext (hi, TYPE_PRECISION (type), uns); | |
1863 | /* Each bit in the result is known if (a) the corresponding bits in | |
1864 | both inputs are known, and (b) the carry-in to that bit position | |
1865 | is known. We can check condition (b) by seeing if we got the same | |
1866 | result with minimised carries as with maximised carries. */ | |
1867 | *mask = double_int_ior (double_int_ior (r1mask, r2mask), | |
1868 | double_int_xor (lo, hi)); | |
1869 | *mask = double_int_ext (*mask, TYPE_PRECISION (type), uns); | |
1870 | /* It shouldn't matter whether we choose lo or hi here. */ | |
1871 | *val = lo; | |
1872 | break; | |
1873 | } | |
1874 | ||
1875 | case MINUS_EXPR: | |
1876 | { | |
1877 | double_int temv, temm; | |
1878 | bit_value_unop_1 (NEGATE_EXPR, r2type, &temv, &temm, | |
1879 | r2type, r2val, r2mask); | |
1880 | bit_value_binop_1 (PLUS_EXPR, type, val, mask, | |
1881 | r1type, r1val, r1mask, | |
1882 | r2type, temv, temm); | |
1883 | break; | |
1884 | } | |
1885 | ||
1886 | case MULT_EXPR: | |
1887 | { | |
1888 | /* Just track trailing zeros in both operands and transfer | |
1889 | them to the other. */ | |
1890 | int r1tz = double_int_ctz (double_int_ior (r1val, r1mask)); | |
1891 | int r2tz = double_int_ctz (double_int_ior (r2val, r2mask)); | |
1892 | if (r1tz + r2tz >= HOST_BITS_PER_DOUBLE_INT) | |
1893 | { | |
1894 | *mask = double_int_zero; | |
1895 | *val = double_int_zero; | |
1896 | } | |
1897 | else if (r1tz + r2tz > 0) | |
1898 | { | |
1899 | *mask = double_int_not (double_int_mask (r1tz + r2tz)); | |
1900 | *mask = double_int_ext (*mask, TYPE_PRECISION (type), uns); | |
1901 | *val = double_int_zero; | |
1902 | } | |
1903 | break; | |
1904 | } | |
1905 | ||
1906 | case EQ_EXPR: | |
1907 | case NE_EXPR: | |
1908 | { | |
1909 | double_int m = double_int_ior (r1mask, r2mask); | |
1910 | if (!double_int_equal_p (double_int_and_not (r1val, m), | |
1911 | double_int_and_not (r2val, m))) | |
1912 | { | |
1913 | *mask = double_int_zero; | |
1914 | *val = ((code == EQ_EXPR) ? double_int_zero : double_int_one); | |
1915 | } | |
1916 | else | |
1917 | { | |
1918 | /* We know the result of a comparison is always one or zero. */ | |
1919 | *mask = double_int_one; | |
1920 | *val = double_int_zero; | |
1921 | } | |
1922 | break; | |
1923 | } | |
1924 | ||
1925 | case GE_EXPR: | |
1926 | case GT_EXPR: | |
1927 | { | |
1928 | double_int tem = r1val; | |
1929 | r1val = r2val; | |
1930 | r2val = tem; | |
1931 | tem = r1mask; | |
1932 | r1mask = r2mask; | |
1933 | r2mask = tem; | |
1934 | code = swap_tree_comparison (code); | |
1935 | } | |
1936 | /* Fallthru. */ | |
1937 | case LT_EXPR: | |
1938 | case LE_EXPR: | |
1939 | { | |
1940 | int minmax, maxmin; | |
1941 | /* If the most significant bits are not known we know nothing. */ | |
1942 | if (double_int_negative_p (r1mask) || double_int_negative_p (r2mask)) | |
1943 | break; | |
1944 | ||
1945 | /* If we know the most significant bits we know the values | |
1946 | value ranges by means of treating varying bits as zero | |
1947 | or one. Do a cross comparison of the max/min pairs. */ | |
1948 | maxmin = double_int_cmp (double_int_ior (r1val, r1mask), | |
1949 | double_int_and_not (r2val, r2mask), uns); | |
1950 | minmax = double_int_cmp (double_int_and_not (r1val, r1mask), | |
1951 | double_int_ior (r2val, r2mask), uns); | |
1952 | if (maxmin < 0) /* r1 is less than r2. */ | |
1953 | { | |
1954 | *mask = double_int_zero; | |
1955 | *val = double_int_one; | |
1956 | } | |
1957 | else if (minmax > 0) /* r1 is not less or equal to r2. */ | |
1958 | { | |
1959 | *mask = double_int_zero; | |
1960 | *val = double_int_zero; | |
1961 | } | |
1962 | else if (maxmin == minmax) /* r1 and r2 are equal. */ | |
1963 | { | |
1964 | /* This probably should never happen as we'd have | |
1965 | folded the thing during fully constant value folding. */ | |
1966 | *mask = double_int_zero; | |
1967 | *val = (code == LE_EXPR ? double_int_one : double_int_zero); | |
1968 | } | |
1969 | else | |
1970 | { | |
1971 | /* We know the result of a comparison is always one or zero. */ | |
1972 | *mask = double_int_one; | |
1973 | *val = double_int_zero; | |
1974 | } | |
1975 | break; | |
1976 | } | |
1977 | ||
1978 | default:; | |
1979 | } | |
1980 | } | |
1981 | ||
1982 | /* Return the propagation value when applying the operation CODE to | |
1983 | the value RHS yielding type TYPE. */ | |
1984 | ||
1985 | static prop_value_t | |
1986 | bit_value_unop (enum tree_code code, tree type, tree rhs) | |
1987 | { | |
1988 | prop_value_t rval = get_value_for_expr (rhs, true); | |
1989 | double_int value, mask; | |
1990 | prop_value_t val; | |
1991 | gcc_assert ((rval.lattice_val == CONSTANT | |
1992 | && TREE_CODE (rval.value) == INTEGER_CST) | |
1993 | || double_int_minus_one_p (rval.mask)); | |
1994 | bit_value_unop_1 (code, type, &value, &mask, | |
1995 | TREE_TYPE (rhs), value_to_double_int (rval), rval.mask); | |
1996 | if (!double_int_minus_one_p (mask)) | |
1997 | { | |
1998 | val.lattice_val = CONSTANT; | |
1999 | val.mask = mask; | |
2000 | /* ??? Delay building trees here. */ | |
2001 | val.value = double_int_to_tree (type, value); | |
2002 | } | |
2003 | else | |
2004 | { | |
2005 | val.lattice_val = VARYING; | |
2006 | val.value = NULL_TREE; | |
2007 | val.mask = double_int_minus_one; | |
2008 | } | |
2009 | return val; | |
2010 | } | |
2011 | ||
2012 | /* Return the propagation value when applying the operation CODE to | |
2013 | the values RHS1 and RHS2 yielding type TYPE. */ | |
2014 | ||
2015 | static prop_value_t | |
2016 | bit_value_binop (enum tree_code code, tree type, tree rhs1, tree rhs2) | |
2017 | { | |
2018 | prop_value_t r1val = get_value_for_expr (rhs1, true); | |
2019 | prop_value_t r2val = get_value_for_expr (rhs2, true); | |
2020 | double_int value, mask; | |
2021 | prop_value_t val; | |
2022 | gcc_assert ((r1val.lattice_val == CONSTANT | |
2023 | && TREE_CODE (r1val.value) == INTEGER_CST) | |
2024 | || double_int_minus_one_p (r1val.mask)); | |
2025 | gcc_assert ((r2val.lattice_val == CONSTANT | |
2026 | && TREE_CODE (r2val.value) == INTEGER_CST) | |
2027 | || double_int_minus_one_p (r2val.mask)); | |
2028 | bit_value_binop_1 (code, type, &value, &mask, | |
2029 | TREE_TYPE (rhs1), value_to_double_int (r1val), r1val.mask, | |
2030 | TREE_TYPE (rhs2), value_to_double_int (r2val), r2val.mask); | |
2031 | if (!double_int_minus_one_p (mask)) | |
2032 | { | |
2033 | val.lattice_val = CONSTANT; | |
2034 | val.mask = mask; | |
2035 | /* ??? Delay building trees here. */ | |
2036 | val.value = double_int_to_tree (type, value); | |
2037 | } | |
2038 | else | |
2039 | { | |
2040 | val.lattice_val = VARYING; | |
2041 | val.value = NULL_TREE; | |
2042 | val.mask = double_int_minus_one; | |
2043 | } | |
2044 | return val; | |
2045 | } | |
2046 | ||
75a70cf9 | 2047 | /* Evaluate statement STMT. |
2048 | Valid only for assignments, calls, conditionals, and switches. */ | |
4ee9c684 | 2049 | |
88dbf20f | 2050 | static prop_value_t |
75a70cf9 | 2051 | evaluate_stmt (gimple stmt) |
4ee9c684 | 2052 | { |
88dbf20f | 2053 | prop_value_t val; |
4f61cce6 | 2054 | tree simplified = NULL_TREE; |
88dbf20f | 2055 | ccp_lattice_t likelyvalue = likely_value (stmt); |
b7e55469 | 2056 | bool is_constant = false; |
88dbf20f | 2057 | |
b7e55469 | 2058 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2059 | { | |
2060 | fprintf (dump_file, "which is likely "); | |
2061 | switch (likelyvalue) | |
2062 | { | |
2063 | case CONSTANT: | |
2064 | fprintf (dump_file, "CONSTANT"); | |
2065 | break; | |
2066 | case UNDEFINED: | |
2067 | fprintf (dump_file, "UNDEFINED"); | |
2068 | break; | |
2069 | case VARYING: | |
2070 | fprintf (dump_file, "VARYING"); | |
2071 | break; | |
2072 | default:; | |
2073 | } | |
2074 | fprintf (dump_file, "\n"); | |
2075 | } | |
add6ee5e | 2076 | |
4ee9c684 | 2077 | /* If the statement is likely to have a CONSTANT result, then try |
2078 | to fold the statement to determine the constant value. */ | |
75a70cf9 | 2079 | /* FIXME. This is the only place that we call ccp_fold. |
2080 | Since likely_value never returns CONSTANT for calls, we will | |
2081 | not attempt to fold them, including builtins that may profit. */ | |
4ee9c684 | 2082 | if (likelyvalue == CONSTANT) |
b7e55469 | 2083 | { |
2084 | fold_defer_overflow_warnings (); | |
2085 | simplified = ccp_fold (stmt); | |
2086 | is_constant = simplified && is_gimple_min_invariant (simplified); | |
2087 | fold_undefer_overflow_warnings (is_constant, stmt, 0); | |
2088 | if (is_constant) | |
2089 | { | |
2090 | /* The statement produced a constant value. */ | |
2091 | val.lattice_val = CONSTANT; | |
2092 | val.value = simplified; | |
2093 | val.mask = double_int_zero; | |
2094 | } | |
2095 | } | |
4ee9c684 | 2096 | /* If the statement is likely to have a VARYING result, then do not |
2097 | bother folding the statement. */ | |
04236c3a | 2098 | else if (likelyvalue == VARYING) |
75a70cf9 | 2099 | { |
590c3166 | 2100 | enum gimple_code code = gimple_code (stmt); |
75a70cf9 | 2101 | if (code == GIMPLE_ASSIGN) |
2102 | { | |
2103 | enum tree_code subcode = gimple_assign_rhs_code (stmt); | |
48e1416a | 2104 | |
75a70cf9 | 2105 | /* Other cases cannot satisfy is_gimple_min_invariant |
2106 | without folding. */ | |
2107 | if (get_gimple_rhs_class (subcode) == GIMPLE_SINGLE_RHS) | |
2108 | simplified = gimple_assign_rhs1 (stmt); | |
2109 | } | |
2110 | else if (code == GIMPLE_SWITCH) | |
2111 | simplified = gimple_switch_index (stmt); | |
2112 | else | |
a65c4d64 | 2113 | /* These cannot satisfy is_gimple_min_invariant without folding. */ |
2114 | gcc_assert (code == GIMPLE_CALL || code == GIMPLE_COND); | |
b7e55469 | 2115 | is_constant = simplified && is_gimple_min_invariant (simplified); |
2116 | if (is_constant) | |
2117 | { | |
2118 | /* The statement produced a constant value. */ | |
2119 | val.lattice_val = CONSTANT; | |
2120 | val.value = simplified; | |
2121 | val.mask = double_int_zero; | |
2122 | } | |
75a70cf9 | 2123 | } |
4ee9c684 | 2124 | |
b7e55469 | 2125 | /* Resort to simplification for bitwise tracking. */ |
2126 | if (flag_tree_bit_ccp | |
2127 | && likelyvalue == CONSTANT | |
2128 | && !is_constant) | |
912f109f | 2129 | { |
b7e55469 | 2130 | enum gimple_code code = gimple_code (stmt); |
153c3b50 | 2131 | tree fndecl; |
b7e55469 | 2132 | val.lattice_val = VARYING; |
2133 | val.value = NULL_TREE; | |
2134 | val.mask = double_int_minus_one; | |
2135 | if (code == GIMPLE_ASSIGN) | |
912f109f | 2136 | { |
b7e55469 | 2137 | enum tree_code subcode = gimple_assign_rhs_code (stmt); |
2138 | tree rhs1 = gimple_assign_rhs1 (stmt); | |
2139 | switch (get_gimple_rhs_class (subcode)) | |
2140 | { | |
2141 | case GIMPLE_SINGLE_RHS: | |
2142 | if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
2143 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
2144 | val = get_value_for_expr (rhs1, true); | |
2145 | break; | |
2146 | ||
2147 | case GIMPLE_UNARY_RHS: | |
2148 | if ((INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
2149 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
2150 | && (INTEGRAL_TYPE_P (gimple_expr_type (stmt)) | |
2151 | || POINTER_TYPE_P (gimple_expr_type (stmt)))) | |
2152 | val = bit_value_unop (subcode, gimple_expr_type (stmt), rhs1); | |
2153 | break; | |
2154 | ||
2155 | case GIMPLE_BINARY_RHS: | |
2156 | if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
2157 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
2158 | { | |
2159 | tree rhs2 = gimple_assign_rhs2 (stmt); | |
2160 | val = bit_value_binop (subcode, | |
2161 | TREE_TYPE (rhs1), rhs1, rhs2); | |
2162 | } | |
2163 | break; | |
2164 | ||
2165 | default:; | |
2166 | } | |
912f109f | 2167 | } |
b7e55469 | 2168 | else if (code == GIMPLE_COND) |
2169 | { | |
2170 | enum tree_code code = gimple_cond_code (stmt); | |
2171 | tree rhs1 = gimple_cond_lhs (stmt); | |
2172 | tree rhs2 = gimple_cond_rhs (stmt); | |
2173 | if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
2174 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
2175 | val = bit_value_binop (code, TREE_TYPE (rhs1), rhs1, rhs2); | |
2176 | } | |
153c3b50 | 2177 | else if (code == GIMPLE_CALL |
2178 | && (fndecl = gimple_call_fndecl (stmt)) | |
2179 | && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL) | |
2180 | { | |
2181 | switch (DECL_FUNCTION_CODE (fndecl)) | |
2182 | { | |
2183 | case BUILT_IN_MALLOC: | |
2184 | case BUILT_IN_REALLOC: | |
2185 | case BUILT_IN_CALLOC: | |
2186 | val.lattice_val = CONSTANT; | |
2187 | val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0); | |
2188 | val.mask = shwi_to_double_int | |
2189 | (~(((HOST_WIDE_INT) MALLOC_ABI_ALIGNMENT) | |
2190 | / BITS_PER_UNIT - 1)); | |
2191 | break; | |
2192 | ||
2193 | case BUILT_IN_ALLOCA: | |
2194 | val.lattice_val = CONSTANT; | |
2195 | val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0); | |
2196 | val.mask = shwi_to_double_int | |
2197 | (~(((HOST_WIDE_INT) BIGGEST_ALIGNMENT) | |
2198 | / BITS_PER_UNIT - 1)); | |
2199 | break; | |
2200 | ||
2201 | default:; | |
2202 | } | |
2203 | } | |
b7e55469 | 2204 | is_constant = (val.lattice_val == CONSTANT); |
912f109f | 2205 | } |
2206 | ||
b7e55469 | 2207 | if (!is_constant) |
4ee9c684 | 2208 | { |
2209 | /* The statement produced a nonconstant value. If the statement | |
88dbf20f | 2210 | had UNDEFINED operands, then the result of the statement |
2211 | should be UNDEFINED. Otherwise, the statement is VARYING. */ | |
bfa30570 | 2212 | if (likelyvalue == UNDEFINED) |
b7e55469 | 2213 | { |
2214 | val.lattice_val = likelyvalue; | |
2215 | val.mask = double_int_zero; | |
2216 | } | |
b765fa12 | 2217 | else |
b7e55469 | 2218 | { |
2219 | val.lattice_val = VARYING; | |
2220 | val.mask = double_int_minus_one; | |
2221 | } | |
b765fa12 | 2222 | |
88dbf20f | 2223 | val.value = NULL_TREE; |
4ee9c684 | 2224 | } |
41511585 | 2225 | |
2226 | return val; | |
4ee9c684 | 2227 | } |
2228 | ||
6688f8ec | 2229 | /* Fold the stmt at *GSI with CCP specific information that propagating |
2230 | and regular folding does not catch. */ | |
2231 | ||
2232 | static bool | |
2233 | ccp_fold_stmt (gimple_stmt_iterator *gsi) | |
2234 | { | |
2235 | gimple stmt = gsi_stmt (*gsi); | |
6688f8ec | 2236 | |
94144e68 | 2237 | switch (gimple_code (stmt)) |
2238 | { | |
2239 | case GIMPLE_COND: | |
2240 | { | |
2241 | prop_value_t val; | |
2242 | /* Statement evaluation will handle type mismatches in constants | |
2243 | more gracefully than the final propagation. This allows us to | |
2244 | fold more conditionals here. */ | |
2245 | val = evaluate_stmt (stmt); | |
2246 | if (val.lattice_val != CONSTANT | |
b7e55469 | 2247 | || !double_int_zero_p (val.mask)) |
94144e68 | 2248 | return false; |
2249 | ||
b7e55469 | 2250 | if (dump_file) |
2251 | { | |
2252 | fprintf (dump_file, "Folding predicate "); | |
2253 | print_gimple_expr (dump_file, stmt, 0, 0); | |
2254 | fprintf (dump_file, " to "); | |
2255 | print_generic_expr (dump_file, val.value, 0); | |
2256 | fprintf (dump_file, "\n"); | |
2257 | } | |
2258 | ||
94144e68 | 2259 | if (integer_zerop (val.value)) |
2260 | gimple_cond_make_false (stmt); | |
2261 | else | |
2262 | gimple_cond_make_true (stmt); | |
6688f8ec | 2263 | |
94144e68 | 2264 | return true; |
2265 | } | |
6688f8ec | 2266 | |
94144e68 | 2267 | case GIMPLE_CALL: |
2268 | { | |
2269 | tree lhs = gimple_call_lhs (stmt); | |
15d138c9 | 2270 | tree val; |
94144e68 | 2271 | tree argt; |
e16f4c39 | 2272 | tree callee; |
94144e68 | 2273 | bool changed = false; |
2274 | unsigned i; | |
2275 | ||
2276 | /* If the call was folded into a constant make sure it goes | |
2277 | away even if we cannot propagate into all uses because of | |
2278 | type issues. */ | |
2279 | if (lhs | |
2280 | && TREE_CODE (lhs) == SSA_NAME | |
15d138c9 | 2281 | && (val = get_constant_value (lhs))) |
94144e68 | 2282 | { |
15d138c9 | 2283 | tree new_rhs = unshare_expr (val); |
338cce8f | 2284 | bool res; |
94144e68 | 2285 | if (!useless_type_conversion_p (TREE_TYPE (lhs), |
2286 | TREE_TYPE (new_rhs))) | |
2287 | new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs); | |
338cce8f | 2288 | res = update_call_from_tree (gsi, new_rhs); |
2289 | gcc_assert (res); | |
94144e68 | 2290 | return true; |
2291 | } | |
2292 | ||
2293 | /* Propagate into the call arguments. Compared to replace_uses_in | |
2294 | this can use the argument slot types for type verification | |
2295 | instead of the current argument type. We also can safely | |
2296 | drop qualifiers here as we are dealing with constants anyway. */ | |
2297 | argt = TYPE_ARG_TYPES (TREE_TYPE (TREE_TYPE (gimple_call_fn (stmt)))); | |
2298 | for (i = 0; i < gimple_call_num_args (stmt) && argt; | |
2299 | ++i, argt = TREE_CHAIN (argt)) | |
2300 | { | |
2301 | tree arg = gimple_call_arg (stmt, i); | |
2302 | if (TREE_CODE (arg) == SSA_NAME | |
15d138c9 | 2303 | && (val = get_constant_value (arg)) |
94144e68 | 2304 | && useless_type_conversion_p |
2305 | (TYPE_MAIN_VARIANT (TREE_VALUE (argt)), | |
15d138c9 | 2306 | TYPE_MAIN_VARIANT (TREE_TYPE (val)))) |
94144e68 | 2307 | { |
15d138c9 | 2308 | gimple_call_set_arg (stmt, i, unshare_expr (val)); |
94144e68 | 2309 | changed = true; |
2310 | } | |
2311 | } | |
e16f4c39 | 2312 | |
2313 | callee = gimple_call_fn (stmt); | |
2314 | if (TREE_CODE (callee) == OBJ_TYPE_REF | |
2315 | && TREE_CODE (OBJ_TYPE_REF_EXPR (callee)) == SSA_NAME) | |
ede94584 | 2316 | { |
e16f4c39 | 2317 | tree expr = OBJ_TYPE_REF_EXPR (callee); |
2318 | OBJ_TYPE_REF_EXPR (callee) = valueize_op (expr); | |
2319 | if (TREE_CODE (OBJ_TYPE_REF_EXPR (callee)) == ADDR_EXPR) | |
2320 | { | |
2321 | tree t; | |
2322 | t = gimple_fold_obj_type_ref (callee, NULL_TREE); | |
2323 | if (t) | |
2324 | { | |
2325 | gimple_call_set_fn (stmt, t); | |
2326 | changed = true; | |
2327 | } | |
2328 | } | |
2329 | OBJ_TYPE_REF_EXPR (callee) = expr; | |
ede94584 | 2330 | } |
94144e68 | 2331 | |
2332 | return changed; | |
2333 | } | |
6688f8ec | 2334 | |
6872bf3c | 2335 | case GIMPLE_ASSIGN: |
2336 | { | |
2337 | tree lhs = gimple_assign_lhs (stmt); | |
15d138c9 | 2338 | tree val; |
6872bf3c | 2339 | |
2340 | /* If we have a load that turned out to be constant replace it | |
2341 | as we cannot propagate into all uses in all cases. */ | |
2342 | if (gimple_assign_single_p (stmt) | |
2343 | && TREE_CODE (lhs) == SSA_NAME | |
15d138c9 | 2344 | && (val = get_constant_value (lhs))) |
6872bf3c | 2345 | { |
15d138c9 | 2346 | tree rhs = unshare_expr (val); |
6872bf3c | 2347 | if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs))) |
182cf5a9 | 2348 | rhs = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), rhs); |
6872bf3c | 2349 | gimple_assign_set_rhs_from_tree (gsi, rhs); |
2350 | return true; | |
2351 | } | |
2352 | ||
2353 | return false; | |
2354 | } | |
2355 | ||
94144e68 | 2356 | default: |
2357 | return false; | |
2358 | } | |
6688f8ec | 2359 | } |
2360 | ||
41511585 | 2361 | /* Visit the assignment statement STMT. Set the value of its LHS to the |
88dbf20f | 2362 | value computed by the RHS and store LHS in *OUTPUT_P. If STMT |
2363 | creates virtual definitions, set the value of each new name to that | |
75a70cf9 | 2364 | of the RHS (if we can derive a constant out of the RHS). |
2365 | Value-returning call statements also perform an assignment, and | |
2366 | are handled here. */ | |
4ee9c684 | 2367 | |
41511585 | 2368 | static enum ssa_prop_result |
75a70cf9 | 2369 | visit_assignment (gimple stmt, tree *output_p) |
4ee9c684 | 2370 | { |
88dbf20f | 2371 | prop_value_t val; |
88dbf20f | 2372 | enum ssa_prop_result retval; |
4ee9c684 | 2373 | |
75a70cf9 | 2374 | tree lhs = gimple_get_lhs (stmt); |
4ee9c684 | 2375 | |
75a70cf9 | 2376 | gcc_assert (gimple_code (stmt) != GIMPLE_CALL |
2377 | || gimple_call_lhs (stmt) != NULL_TREE); | |
2378 | ||
15d138c9 | 2379 | if (gimple_assign_single_p (stmt) |
2380 | && gimple_assign_rhs_code (stmt) == SSA_NAME) | |
2381 | /* For a simple copy operation, we copy the lattice values. */ | |
2382 | val = *get_value (gimple_assign_rhs1 (stmt)); | |
41511585 | 2383 | else |
75a70cf9 | 2384 | /* Evaluate the statement, which could be |
2385 | either a GIMPLE_ASSIGN or a GIMPLE_CALL. */ | |
04236c3a | 2386 | val = evaluate_stmt (stmt); |
4ee9c684 | 2387 | |
88dbf20f | 2388 | retval = SSA_PROP_NOT_INTERESTING; |
4ee9c684 | 2389 | |
41511585 | 2390 | /* Set the lattice value of the statement's output. */ |
88dbf20f | 2391 | if (TREE_CODE (lhs) == SSA_NAME) |
4ee9c684 | 2392 | { |
88dbf20f | 2393 | /* If STMT is an assignment to an SSA_NAME, we only have one |
2394 | value to set. */ | |
2395 | if (set_lattice_value (lhs, val)) | |
2396 | { | |
2397 | *output_p = lhs; | |
2398 | if (val.lattice_val == VARYING) | |
2399 | retval = SSA_PROP_VARYING; | |
2400 | else | |
2401 | retval = SSA_PROP_INTERESTING; | |
2402 | } | |
4ee9c684 | 2403 | } |
88dbf20f | 2404 | |
2405 | return retval; | |
4ee9c684 | 2406 | } |
2407 | ||
4ee9c684 | 2408 | |
41511585 | 2409 | /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING |
2410 | if it can determine which edge will be taken. Otherwise, return | |
2411 | SSA_PROP_VARYING. */ | |
2412 | ||
2413 | static enum ssa_prop_result | |
75a70cf9 | 2414 | visit_cond_stmt (gimple stmt, edge *taken_edge_p) |
4ee9c684 | 2415 | { |
88dbf20f | 2416 | prop_value_t val; |
41511585 | 2417 | basic_block block; |
2418 | ||
75a70cf9 | 2419 | block = gimple_bb (stmt); |
41511585 | 2420 | val = evaluate_stmt (stmt); |
b7e55469 | 2421 | if (val.lattice_val != CONSTANT |
2422 | || !double_int_zero_p (val.mask)) | |
2423 | return SSA_PROP_VARYING; | |
41511585 | 2424 | |
2425 | /* Find which edge out of the conditional block will be taken and add it | |
2426 | to the worklist. If no single edge can be determined statically, | |
2427 | return SSA_PROP_VARYING to feed all the outgoing edges to the | |
2428 | propagation engine. */ | |
b7e55469 | 2429 | *taken_edge_p = find_taken_edge (block, val.value); |
41511585 | 2430 | if (*taken_edge_p) |
2431 | return SSA_PROP_INTERESTING; | |
2432 | else | |
2433 | return SSA_PROP_VARYING; | |
4ee9c684 | 2434 | } |
2435 | ||
4ee9c684 | 2436 | |
41511585 | 2437 | /* Evaluate statement STMT. If the statement produces an output value and |
2438 | its evaluation changes the lattice value of its output, return | |
2439 | SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the | |
2440 | output value. | |
48e1416a | 2441 | |
41511585 | 2442 | If STMT is a conditional branch and we can determine its truth |
2443 | value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying | |
2444 | value, return SSA_PROP_VARYING. */ | |
4ee9c684 | 2445 | |
41511585 | 2446 | static enum ssa_prop_result |
75a70cf9 | 2447 | ccp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p) |
41511585 | 2448 | { |
41511585 | 2449 | tree def; |
2450 | ssa_op_iter iter; | |
4ee9c684 | 2451 | |
41511585 | 2452 | if (dump_file && (dump_flags & TDF_DETAILS)) |
4ee9c684 | 2453 | { |
88dbf20f | 2454 | fprintf (dump_file, "\nVisiting statement:\n"); |
75a70cf9 | 2455 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
4ee9c684 | 2456 | } |
4ee9c684 | 2457 | |
75a70cf9 | 2458 | switch (gimple_code (stmt)) |
4ee9c684 | 2459 | { |
75a70cf9 | 2460 | case GIMPLE_ASSIGN: |
2461 | /* If the statement is an assignment that produces a single | |
2462 | output value, evaluate its RHS to see if the lattice value of | |
2463 | its output has changed. */ | |
2464 | return visit_assignment (stmt, output_p); | |
2465 | ||
2466 | case GIMPLE_CALL: | |
2467 | /* A value-returning call also performs an assignment. */ | |
2468 | if (gimple_call_lhs (stmt) != NULL_TREE) | |
2469 | return visit_assignment (stmt, output_p); | |
2470 | break; | |
2471 | ||
2472 | case GIMPLE_COND: | |
2473 | case GIMPLE_SWITCH: | |
2474 | /* If STMT is a conditional branch, see if we can determine | |
2475 | which branch will be taken. */ | |
2476 | /* FIXME. It appears that we should be able to optimize | |
2477 | computed GOTOs here as well. */ | |
2478 | return visit_cond_stmt (stmt, taken_edge_p); | |
2479 | ||
2480 | default: | |
2481 | break; | |
4ee9c684 | 2482 | } |
4ee9c684 | 2483 | |
41511585 | 2484 | /* Any other kind of statement is not interesting for constant |
2485 | propagation and, therefore, not worth simulating. */ | |
41511585 | 2486 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2487 | fprintf (dump_file, "No interesting values produced. Marked VARYING.\n"); | |
4ee9c684 | 2488 | |
41511585 | 2489 | /* Definitions made by statements other than assignments to |
2490 | SSA_NAMEs represent unknown modifications to their outputs. | |
2491 | Mark them VARYING. */ | |
88dbf20f | 2492 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) |
2493 | { | |
b7e55469 | 2494 | prop_value_t v = { VARYING, NULL_TREE, { -1, (HOST_WIDE_INT) -1 } }; |
88dbf20f | 2495 | set_lattice_value (def, v); |
2496 | } | |
4ee9c684 | 2497 | |
41511585 | 2498 | return SSA_PROP_VARYING; |
2499 | } | |
4ee9c684 | 2500 | |
4ee9c684 | 2501 | |
88dbf20f | 2502 | /* Main entry point for SSA Conditional Constant Propagation. */ |
41511585 | 2503 | |
33a34f1e | 2504 | static unsigned int |
61207d43 | 2505 | do_ssa_ccp (void) |
41511585 | 2506 | { |
2507 | ccp_initialize (); | |
2508 | ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node); | |
33a34f1e | 2509 | if (ccp_finalize ()) |
eb9161e7 | 2510 | return (TODO_cleanup_cfg | TODO_update_ssa | TODO_remove_unused_locals); |
33a34f1e | 2511 | else |
2512 | return 0; | |
4ee9c684 | 2513 | } |
2514 | ||
5664499b | 2515 | |
2516 | static bool | |
41511585 | 2517 | gate_ccp (void) |
5664499b | 2518 | { |
41511585 | 2519 | return flag_tree_ccp != 0; |
5664499b | 2520 | } |
2521 | ||
4ee9c684 | 2522 | |
48e1416a | 2523 | struct gimple_opt_pass pass_ccp = |
41511585 | 2524 | { |
20099e35 | 2525 | { |
2526 | GIMPLE_PASS, | |
41511585 | 2527 | "ccp", /* name */ |
2528 | gate_ccp, /* gate */ | |
88dbf20f | 2529 | do_ssa_ccp, /* execute */ |
41511585 | 2530 | NULL, /* sub */ |
2531 | NULL, /* next */ | |
2532 | 0, /* static_pass_number */ | |
2533 | TV_TREE_CCP, /* tv_id */ | |
49290934 | 2534 | PROP_cfg | PROP_ssa, /* properties_required */ |
41511585 | 2535 | 0, /* properties_provided */ |
b6246c40 | 2536 | 0, /* properties_destroyed */ |
41511585 | 2537 | 0, /* todo_flags_start */ |
33a34f1e | 2538 | TODO_dump_func | TODO_verify_ssa |
20099e35 | 2539 | | TODO_verify_stmts | TODO_ggc_collect/* todo_flags_finish */ |
2540 | } | |
41511585 | 2541 | }; |
4ee9c684 | 2542 | |
4ee9c684 | 2543 | |
75a70cf9 | 2544 | |
bdd0e199 | 2545 | /* Try to optimize out __builtin_stack_restore. Optimize it out |
2546 | if there is another __builtin_stack_restore in the same basic | |
2547 | block and no calls or ASM_EXPRs are in between, or if this block's | |
2548 | only outgoing edge is to EXIT_BLOCK and there are no calls or | |
2549 | ASM_EXPRs after this __builtin_stack_restore. */ | |
2550 | ||
2551 | static tree | |
75a70cf9 | 2552 | optimize_stack_restore (gimple_stmt_iterator i) |
bdd0e199 | 2553 | { |
6ea999da | 2554 | tree callee; |
2555 | gimple stmt; | |
75a70cf9 | 2556 | |
2557 | basic_block bb = gsi_bb (i); | |
2558 | gimple call = gsi_stmt (i); | |
bdd0e199 | 2559 | |
75a70cf9 | 2560 | if (gimple_code (call) != GIMPLE_CALL |
2561 | || gimple_call_num_args (call) != 1 | |
2562 | || TREE_CODE (gimple_call_arg (call, 0)) != SSA_NAME | |
2563 | || !POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call, 0)))) | |
bdd0e199 | 2564 | return NULL_TREE; |
2565 | ||
75a70cf9 | 2566 | for (gsi_next (&i); !gsi_end_p (i); gsi_next (&i)) |
bdd0e199 | 2567 | { |
75a70cf9 | 2568 | stmt = gsi_stmt (i); |
2569 | if (gimple_code (stmt) == GIMPLE_ASM) | |
bdd0e199 | 2570 | return NULL_TREE; |
75a70cf9 | 2571 | if (gimple_code (stmt) != GIMPLE_CALL) |
bdd0e199 | 2572 | continue; |
2573 | ||
75a70cf9 | 2574 | callee = gimple_call_fndecl (stmt); |
c40a6f90 | 2575 | if (!callee |
2576 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL | |
2577 | /* All regular builtins are ok, just obviously not alloca. */ | |
2578 | || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA) | |
bdd0e199 | 2579 | return NULL_TREE; |
2580 | ||
2581 | if (DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_RESTORE) | |
6ea999da | 2582 | goto second_stack_restore; |
bdd0e199 | 2583 | } |
2584 | ||
6ea999da | 2585 | if (!gsi_end_p (i)) |
bdd0e199 | 2586 | return NULL_TREE; |
2587 | ||
6ea999da | 2588 | /* Allow one successor of the exit block, or zero successors. */ |
2589 | switch (EDGE_COUNT (bb->succs)) | |
2590 | { | |
2591 | case 0: | |
2592 | break; | |
2593 | case 1: | |
2594 | if (single_succ_edge (bb)->dest != EXIT_BLOCK_PTR) | |
2595 | return NULL_TREE; | |
2596 | break; | |
2597 | default: | |
2598 | return NULL_TREE; | |
2599 | } | |
2600 | second_stack_restore: | |
bdd0e199 | 2601 | |
6ea999da | 2602 | /* If there's exactly one use, then zap the call to __builtin_stack_save. |
2603 | If there are multiple uses, then the last one should remove the call. | |
2604 | In any case, whether the call to __builtin_stack_save can be removed | |
2605 | or not is irrelevant to removing the call to __builtin_stack_restore. */ | |
2606 | if (has_single_use (gimple_call_arg (call, 0))) | |
2607 | { | |
2608 | gimple stack_save = SSA_NAME_DEF_STMT (gimple_call_arg (call, 0)); | |
2609 | if (is_gimple_call (stack_save)) | |
2610 | { | |
2611 | callee = gimple_call_fndecl (stack_save); | |
2612 | if (callee | |
2613 | && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL | |
2614 | && DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_SAVE) | |
2615 | { | |
2616 | gimple_stmt_iterator stack_save_gsi; | |
2617 | tree rhs; | |
bdd0e199 | 2618 | |
6ea999da | 2619 | stack_save_gsi = gsi_for_stmt (stack_save); |
2620 | rhs = build_int_cst (TREE_TYPE (gimple_call_arg (call, 0)), 0); | |
2621 | update_call_from_tree (&stack_save_gsi, rhs); | |
2622 | } | |
2623 | } | |
2624 | } | |
bdd0e199 | 2625 | |
75a70cf9 | 2626 | /* No effect, so the statement will be deleted. */ |
bdd0e199 | 2627 | return integer_zero_node; |
2628 | } | |
75a70cf9 | 2629 | |
8a58ed0a | 2630 | /* If va_list type is a simple pointer and nothing special is needed, |
2631 | optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0), | |
2632 | __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple | |
2633 | pointer assignment. */ | |
2634 | ||
2635 | static tree | |
75a70cf9 | 2636 | optimize_stdarg_builtin (gimple call) |
8a58ed0a | 2637 | { |
5f57a8b1 | 2638 | tree callee, lhs, rhs, cfun_va_list; |
8a58ed0a | 2639 | bool va_list_simple_ptr; |
389dd41b | 2640 | location_t loc = gimple_location (call); |
8a58ed0a | 2641 | |
75a70cf9 | 2642 | if (gimple_code (call) != GIMPLE_CALL) |
8a58ed0a | 2643 | return NULL_TREE; |
2644 | ||
75a70cf9 | 2645 | callee = gimple_call_fndecl (call); |
5f57a8b1 | 2646 | |
2647 | cfun_va_list = targetm.fn_abi_va_list (callee); | |
2648 | va_list_simple_ptr = POINTER_TYPE_P (cfun_va_list) | |
2649 | && (TREE_TYPE (cfun_va_list) == void_type_node | |
2650 | || TREE_TYPE (cfun_va_list) == char_type_node); | |
2651 | ||
8a58ed0a | 2652 | switch (DECL_FUNCTION_CODE (callee)) |
2653 | { | |
2654 | case BUILT_IN_VA_START: | |
2655 | if (!va_list_simple_ptr | |
2656 | || targetm.expand_builtin_va_start != NULL | |
75a70cf9 | 2657 | || built_in_decls[BUILT_IN_NEXT_ARG] == NULL) |
8a58ed0a | 2658 | return NULL_TREE; |
2659 | ||
75a70cf9 | 2660 | if (gimple_call_num_args (call) != 2) |
8a58ed0a | 2661 | return NULL_TREE; |
2662 | ||
75a70cf9 | 2663 | lhs = gimple_call_arg (call, 0); |
8a58ed0a | 2664 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) |
2665 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
5f57a8b1 | 2666 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
8a58ed0a | 2667 | return NULL_TREE; |
48e1416a | 2668 | |
389dd41b | 2669 | lhs = build_fold_indirect_ref_loc (loc, lhs); |
2670 | rhs = build_call_expr_loc (loc, built_in_decls[BUILT_IN_NEXT_ARG], | |
75a70cf9 | 2671 | 1, integer_zero_node); |
389dd41b | 2672 | rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); |
8a58ed0a | 2673 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); |
2674 | ||
2675 | case BUILT_IN_VA_COPY: | |
2676 | if (!va_list_simple_ptr) | |
2677 | return NULL_TREE; | |
2678 | ||
75a70cf9 | 2679 | if (gimple_call_num_args (call) != 2) |
8a58ed0a | 2680 | return NULL_TREE; |
2681 | ||
75a70cf9 | 2682 | lhs = gimple_call_arg (call, 0); |
8a58ed0a | 2683 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) |
2684 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
5f57a8b1 | 2685 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
8a58ed0a | 2686 | return NULL_TREE; |
2687 | ||
389dd41b | 2688 | lhs = build_fold_indirect_ref_loc (loc, lhs); |
75a70cf9 | 2689 | rhs = gimple_call_arg (call, 1); |
8a58ed0a | 2690 | if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs)) |
5f57a8b1 | 2691 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
8a58ed0a | 2692 | return NULL_TREE; |
2693 | ||
389dd41b | 2694 | rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); |
8a58ed0a | 2695 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); |
2696 | ||
2697 | case BUILT_IN_VA_END: | |
75a70cf9 | 2698 | /* No effect, so the statement will be deleted. */ |
8a58ed0a | 2699 | return integer_zero_node; |
2700 | ||
2701 | default: | |
2702 | gcc_unreachable (); | |
2703 | } | |
2704 | } | |
75a70cf9 | 2705 | |
4ee9c684 | 2706 | /* A simple pass that attempts to fold all builtin functions. This pass |
2707 | is run after we've propagated as many constants as we can. */ | |
2708 | ||
2a1990e9 | 2709 | static unsigned int |
4ee9c684 | 2710 | execute_fold_all_builtins (void) |
2711 | { | |
b36237eb | 2712 | bool cfg_changed = false; |
4ee9c684 | 2713 | basic_block bb; |
b1b7c0c4 | 2714 | unsigned int todoflags = 0; |
48e1416a | 2715 | |
4ee9c684 | 2716 | FOR_EACH_BB (bb) |
2717 | { | |
75a70cf9 | 2718 | gimple_stmt_iterator i; |
2719 | for (i = gsi_start_bb (bb); !gsi_end_p (i); ) | |
4ee9c684 | 2720 | { |
75a70cf9 | 2721 | gimple stmt, old_stmt; |
4ee9c684 | 2722 | tree callee, result; |
0a39fd54 | 2723 | enum built_in_function fcode; |
4ee9c684 | 2724 | |
75a70cf9 | 2725 | stmt = gsi_stmt (i); |
2726 | ||
2727 | if (gimple_code (stmt) != GIMPLE_CALL) | |
0a39fd54 | 2728 | { |
75a70cf9 | 2729 | gsi_next (&i); |
0a39fd54 | 2730 | continue; |
2731 | } | |
75a70cf9 | 2732 | callee = gimple_call_fndecl (stmt); |
4ee9c684 | 2733 | if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) |
0a39fd54 | 2734 | { |
75a70cf9 | 2735 | gsi_next (&i); |
0a39fd54 | 2736 | continue; |
2737 | } | |
2738 | fcode = DECL_FUNCTION_CODE (callee); | |
4ee9c684 | 2739 | |
2d18b16d | 2740 | result = gimple_fold_builtin (stmt); |
5a4b7e1e | 2741 | |
2742 | if (result) | |
75a70cf9 | 2743 | gimple_remove_stmt_histograms (cfun, stmt); |
5a4b7e1e | 2744 | |
4ee9c684 | 2745 | if (!result) |
2746 | switch (DECL_FUNCTION_CODE (callee)) | |
2747 | { | |
2748 | case BUILT_IN_CONSTANT_P: | |
2749 | /* Resolve __builtin_constant_p. If it hasn't been | |
2750 | folded to integer_one_node by now, it's fairly | |
2751 | certain that the value simply isn't constant. */ | |
75a70cf9 | 2752 | result = integer_zero_node; |
4ee9c684 | 2753 | break; |
2754 | ||
bdd0e199 | 2755 | case BUILT_IN_STACK_RESTORE: |
75a70cf9 | 2756 | result = optimize_stack_restore (i); |
8a58ed0a | 2757 | if (result) |
2758 | break; | |
75a70cf9 | 2759 | gsi_next (&i); |
8a58ed0a | 2760 | continue; |
2761 | ||
2762 | case BUILT_IN_VA_START: | |
2763 | case BUILT_IN_VA_END: | |
2764 | case BUILT_IN_VA_COPY: | |
2765 | /* These shouldn't be folded before pass_stdarg. */ | |
75a70cf9 | 2766 | result = optimize_stdarg_builtin (stmt); |
bdd0e199 | 2767 | if (result) |
2768 | break; | |
2769 | /* FALLTHRU */ | |
2770 | ||
4ee9c684 | 2771 | default: |
75a70cf9 | 2772 | gsi_next (&i); |
4ee9c684 | 2773 | continue; |
2774 | } | |
2775 | ||
2776 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2777 | { | |
2778 | fprintf (dump_file, "Simplified\n "); | |
75a70cf9 | 2779 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
4ee9c684 | 2780 | } |
2781 | ||
75a70cf9 | 2782 | old_stmt = stmt; |
75a70cf9 | 2783 | if (!update_call_from_tree (&i, result)) |
0fefde02 | 2784 | { |
2785 | gimplify_and_update_call_from_tree (&i, result); | |
2786 | todoflags |= TODO_update_address_taken; | |
2787 | } | |
de6ed584 | 2788 | |
75a70cf9 | 2789 | stmt = gsi_stmt (i); |
4c5fd53c | 2790 | update_stmt (stmt); |
de6ed584 | 2791 | |
75a70cf9 | 2792 | if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt) |
2793 | && gimple_purge_dead_eh_edges (bb)) | |
b36237eb | 2794 | cfg_changed = true; |
4ee9c684 | 2795 | |
2796 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2797 | { | |
2798 | fprintf (dump_file, "to\n "); | |
75a70cf9 | 2799 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
4ee9c684 | 2800 | fprintf (dump_file, "\n"); |
2801 | } | |
0a39fd54 | 2802 | |
2803 | /* Retry the same statement if it changed into another | |
2804 | builtin, there might be new opportunities now. */ | |
75a70cf9 | 2805 | if (gimple_code (stmt) != GIMPLE_CALL) |
0a39fd54 | 2806 | { |
75a70cf9 | 2807 | gsi_next (&i); |
0a39fd54 | 2808 | continue; |
2809 | } | |
75a70cf9 | 2810 | callee = gimple_call_fndecl (stmt); |
0a39fd54 | 2811 | if (!callee |
75a70cf9 | 2812 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL |
0a39fd54 | 2813 | || DECL_FUNCTION_CODE (callee) == fcode) |
75a70cf9 | 2814 | gsi_next (&i); |
4ee9c684 | 2815 | } |
2816 | } | |
48e1416a | 2817 | |
b36237eb | 2818 | /* Delete unreachable blocks. */ |
b1b7c0c4 | 2819 | if (cfg_changed) |
2820 | todoflags |= TODO_cleanup_cfg; | |
48e1416a | 2821 | |
b1b7c0c4 | 2822 | return todoflags; |
4ee9c684 | 2823 | } |
2824 | ||
41511585 | 2825 | |
48e1416a | 2826 | struct gimple_opt_pass pass_fold_builtins = |
4ee9c684 | 2827 | { |
20099e35 | 2828 | { |
2829 | GIMPLE_PASS, | |
4ee9c684 | 2830 | "fab", /* name */ |
2831 | NULL, /* gate */ | |
2832 | execute_fold_all_builtins, /* execute */ | |
2833 | NULL, /* sub */ | |
2834 | NULL, /* next */ | |
2835 | 0, /* static_pass_number */ | |
0b1615c1 | 2836 | TV_NONE, /* tv_id */ |
49290934 | 2837 | PROP_cfg | PROP_ssa, /* properties_required */ |
4ee9c684 | 2838 | 0, /* properties_provided */ |
2839 | 0, /* properties_destroyed */ | |
2840 | 0, /* todo_flags_start */ | |
909e5ecb | 2841 | TODO_dump_func |
2842 | | TODO_verify_ssa | |
20099e35 | 2843 | | TODO_update_ssa /* todo_flags_finish */ |
2844 | } | |
4ee9c684 | 2845 | }; |