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4ee9c684 | 1 | /* Conditional constant propagation pass for the GNU compiler. |
3aea1f79 | 2 | Copyright (C) 2000-2014 Free Software Foundation, Inc. |
4ee9c684 | 3 | Adapted from original RTL SSA-CCP by Daniel Berlin <dberlin@dberlin.org> |
4 | Adapted to GIMPLE trees by Diego Novillo <dnovillo@redhat.com> | |
5 | ||
6 | This file is part of GCC. | |
48e1416a | 7 | |
4ee9c684 | 8 | GCC is free software; you can redistribute it and/or modify it |
9 | under the terms of the GNU General Public License as published by the | |
8c4c00c1 | 10 | Free Software Foundation; either version 3, or (at your option) any |
4ee9c684 | 11 | later version. |
48e1416a | 12 | |
4ee9c684 | 13 | GCC is distributed in the hope that it will be useful, but WITHOUT |
14 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
16 | for more details. | |
48e1416a | 17 | |
4ee9c684 | 18 | You should have received a copy of the GNU General Public License |
8c4c00c1 | 19 | along with GCC; see the file COPYING3. If not see |
20 | <http://www.gnu.org/licenses/>. */ | |
4ee9c684 | 21 | |
88dbf20f | 22 | /* Conditional constant propagation (CCP) is based on the SSA |
23 | propagation engine (tree-ssa-propagate.c). Constant assignments of | |
24 | the form VAR = CST are propagated from the assignments into uses of | |
25 | VAR, which in turn may generate new constants. The simulation uses | |
26 | a four level lattice to keep track of constant values associated | |
27 | with SSA names. Given an SSA name V_i, it may take one of the | |
28 | following values: | |
29 | ||
bfa30570 | 30 | UNINITIALIZED -> the initial state of the value. This value |
31 | is replaced with a correct initial value | |
32 | the first time the value is used, so the | |
33 | rest of the pass does not need to care about | |
34 | it. Using this value simplifies initialization | |
35 | of the pass, and prevents us from needlessly | |
36 | scanning statements that are never reached. | |
88dbf20f | 37 | |
38 | UNDEFINED -> V_i is a local variable whose definition | |
39 | has not been processed yet. Therefore we | |
40 | don't yet know if its value is a constant | |
41 | or not. | |
42 | ||
43 | CONSTANT -> V_i has been found to hold a constant | |
44 | value C. | |
45 | ||
46 | VARYING -> V_i cannot take a constant value, or if it | |
47 | does, it is not possible to determine it | |
48 | at compile time. | |
49 | ||
50 | The core of SSA-CCP is in ccp_visit_stmt and ccp_visit_phi_node: | |
51 | ||
52 | 1- In ccp_visit_stmt, we are interested in assignments whose RHS | |
53 | evaluates into a constant and conditional jumps whose predicate | |
54 | evaluates into a boolean true or false. When an assignment of | |
55 | the form V_i = CONST is found, V_i's lattice value is set to | |
56 | CONSTANT and CONST is associated with it. This causes the | |
57 | propagation engine to add all the SSA edges coming out the | |
58 | assignment into the worklists, so that statements that use V_i | |
59 | can be visited. | |
60 | ||
61 | If the statement is a conditional with a constant predicate, we | |
62 | mark the outgoing edges as executable or not executable | |
63 | depending on the predicate's value. This is then used when | |
64 | visiting PHI nodes to know when a PHI argument can be ignored. | |
48e1416a | 65 | |
88dbf20f | 66 | |
67 | 2- In ccp_visit_phi_node, if all the PHI arguments evaluate to the | |
68 | same constant C, then the LHS of the PHI is set to C. This | |
69 | evaluation is known as the "meet operation". Since one of the | |
70 | goals of this evaluation is to optimistically return constant | |
71 | values as often as possible, it uses two main short cuts: | |
72 | ||
73 | - If an argument is flowing in through a non-executable edge, it | |
74 | is ignored. This is useful in cases like this: | |
75 | ||
76 | if (PRED) | |
77 | a_9 = 3; | |
78 | else | |
79 | a_10 = 100; | |
80 | a_11 = PHI (a_9, a_10) | |
81 | ||
82 | If PRED is known to always evaluate to false, then we can | |
83 | assume that a_11 will always take its value from a_10, meaning | |
84 | that instead of consider it VARYING (a_9 and a_10 have | |
85 | different values), we can consider it CONSTANT 100. | |
86 | ||
87 | - If an argument has an UNDEFINED value, then it does not affect | |
88 | the outcome of the meet operation. If a variable V_i has an | |
89 | UNDEFINED value, it means that either its defining statement | |
90 | hasn't been visited yet or V_i has no defining statement, in | |
91 | which case the original symbol 'V' is being used | |
92 | uninitialized. Since 'V' is a local variable, the compiler | |
93 | may assume any initial value for it. | |
94 | ||
95 | ||
96 | After propagation, every variable V_i that ends up with a lattice | |
97 | value of CONSTANT will have the associated constant value in the | |
98 | array CONST_VAL[i].VALUE. That is fed into substitute_and_fold for | |
99 | final substitution and folding. | |
100 | ||
e913b5cd | 101 | This algorithm uses wide-ints at the max precision of the target. |
102 | This means that, with one uninteresting exception, variables with | |
103 | UNSIGNED types never go to VARYING because the bits above the | |
104 | precision of the type of the variable are always zero. The | |
105 | uninteresting case is a variable of UNSIGNED type that has the | |
106 | maximum precision of the target. Such variables can go to VARYING, | |
107 | but this causes no loss of infomation since these variables will | |
108 | never be extended. | |
109 | ||
4ee9c684 | 110 | References: |
111 | ||
112 | Constant propagation with conditional branches, | |
113 | Wegman and Zadeck, ACM TOPLAS 13(2):181-210. | |
114 | ||
115 | Building an Optimizing Compiler, | |
116 | Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9. | |
117 | ||
118 | Advanced Compiler Design and Implementation, | |
119 | Steven Muchnick, Morgan Kaufmann, 1997, Section 12.6 */ | |
120 | ||
121 | #include "config.h" | |
122 | #include "system.h" | |
123 | #include "coretypes.h" | |
124 | #include "tm.h" | |
4ee9c684 | 125 | #include "tree.h" |
9ed99284 | 126 | #include "stor-layout.h" |
41511585 | 127 | #include "flags.h" |
4ee9c684 | 128 | #include "tm_p.h" |
4ee9c684 | 129 | #include "basic-block.h" |
41511585 | 130 | #include "function.h" |
ce084dfc | 131 | #include "gimple-pretty-print.h" |
bc61cadb | 132 | #include "hash-table.h" |
133 | #include "tree-ssa-alias.h" | |
134 | #include "internal-fn.h" | |
135 | #include "gimple-fold.h" | |
136 | #include "tree-eh.h" | |
137 | #include "gimple-expr.h" | |
138 | #include "is-a.h" | |
073c1fd5 | 139 | #include "gimple.h" |
a8783bee | 140 | #include "gimplify.h" |
dcf1a1ec | 141 | #include "gimple-iterator.h" |
073c1fd5 | 142 | #include "gimple-ssa.h" |
143 | #include "tree-cfg.h" | |
144 | #include "tree-phinodes.h" | |
145 | #include "ssa-iterators.h" | |
9ed99284 | 146 | #include "stringpool.h" |
073c1fd5 | 147 | #include "tree-ssanames.h" |
4ee9c684 | 148 | #include "tree-pass.h" |
41511585 | 149 | #include "tree-ssa-propagate.h" |
5a4b7e1e | 150 | #include "value-prof.h" |
41511585 | 151 | #include "langhooks.h" |
8782adcf | 152 | #include "target.h" |
0b205f4c | 153 | #include "diagnostic-core.h" |
43fb76c1 | 154 | #include "dbgcnt.h" |
9a65cc0a | 155 | #include "params.h" |
e913b5cd | 156 | #include "wide-int-print.h" |
4ee9c684 | 157 | |
2dc10fae | 158 | |
4ee9c684 | 159 | /* Possible lattice values. */ |
160 | typedef enum | |
161 | { | |
bfa30570 | 162 | UNINITIALIZED, |
4ee9c684 | 163 | UNDEFINED, |
164 | CONSTANT, | |
165 | VARYING | |
88dbf20f | 166 | } ccp_lattice_t; |
4ee9c684 | 167 | |
14f101cf | 168 | struct prop_value_d { |
169 | /* Lattice value. */ | |
170 | ccp_lattice_t lattice_val; | |
171 | ||
172 | /* Propagated value. */ | |
173 | tree value; | |
b7e55469 | 174 | |
e913b5cd | 175 | /* Mask that applies to the propagated value during CCP. For X |
176 | with a CONSTANT lattice value X & ~mask == value & ~mask. The | |
177 | zero bits in the mask cover constant values. The ones mean no | |
178 | information. */ | |
5de9d3ed | 179 | widest_int mask; |
14f101cf | 180 | }; |
181 | ||
182 | typedef struct prop_value_d prop_value_t; | |
183 | ||
88dbf20f | 184 | /* Array of propagated constant values. After propagation, |
185 | CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If | |
186 | the constant is held in an SSA name representing a memory store | |
4fb5e5ca | 187 | (i.e., a VDEF), CONST_VAL[I].MEM_REF will contain the actual |
188 | memory reference used to store (i.e., the LHS of the assignment | |
189 | doing the store). */ | |
20140406 | 190 | static prop_value_t *const_val; |
285df01b | 191 | static unsigned n_const_val; |
4ee9c684 | 192 | |
f5faab84 | 193 | static void canonicalize_value (prop_value_t *); |
6688f8ec | 194 | static bool ccp_fold_stmt (gimple_stmt_iterator *); |
4af351a8 | 195 | |
88dbf20f | 196 | /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */ |
01406fc0 | 197 | |
198 | static void | |
88dbf20f | 199 | dump_lattice_value (FILE *outf, const char *prefix, prop_value_t val) |
01406fc0 | 200 | { |
41511585 | 201 | switch (val.lattice_val) |
01406fc0 | 202 | { |
88dbf20f | 203 | case UNINITIALIZED: |
204 | fprintf (outf, "%sUNINITIALIZED", prefix); | |
205 | break; | |
41511585 | 206 | case UNDEFINED: |
207 | fprintf (outf, "%sUNDEFINED", prefix); | |
208 | break; | |
209 | case VARYING: | |
210 | fprintf (outf, "%sVARYING", prefix); | |
211 | break; | |
41511585 | 212 | case CONSTANT: |
b7e55469 | 213 | if (TREE_CODE (val.value) != INTEGER_CST |
796b6678 | 214 | || val.mask == 0) |
16ab4e97 | 215 | { |
216 | fprintf (outf, "%sCONSTANT ", prefix); | |
217 | print_generic_expr (outf, val.value, dump_flags); | |
218 | } | |
b7e55469 | 219 | else |
220 | { | |
5de9d3ed | 221 | wide_int cval = wi::bit_and_not (wi::to_widest (val.value), val.mask); |
e913b5cd | 222 | fprintf (outf, "%sCONSTANT ", prefix); |
223 | print_hex (cval, outf); | |
224 | fprintf (outf, " ("); | |
225 | print_hex (val.mask, outf); | |
226 | fprintf (outf, ")"); | |
b7e55469 | 227 | } |
41511585 | 228 | break; |
229 | default: | |
8c0963c4 | 230 | gcc_unreachable (); |
41511585 | 231 | } |
01406fc0 | 232 | } |
4ee9c684 | 233 | |
4ee9c684 | 234 | |
88dbf20f | 235 | /* Print lattice value VAL to stderr. */ |
236 | ||
237 | void debug_lattice_value (prop_value_t val); | |
238 | ||
4b987fac | 239 | DEBUG_FUNCTION void |
88dbf20f | 240 | debug_lattice_value (prop_value_t val) |
241 | { | |
242 | dump_lattice_value (stderr, "", val); | |
243 | fprintf (stderr, "\n"); | |
244 | } | |
4ee9c684 | 245 | |
9c1be15e | 246 | /* Extend NONZERO_BITS to a full mask, with the upper bits being set. */ |
247 | ||
248 | static widest_int | |
249 | extend_mask (const wide_int &nonzero_bits) | |
250 | { | |
251 | return (wi::mask <widest_int> (wi::get_precision (nonzero_bits), true) | |
252 | | widest_int::from (nonzero_bits, UNSIGNED)); | |
253 | } | |
4ee9c684 | 254 | |
88dbf20f | 255 | /* Compute a default value for variable VAR and store it in the |
256 | CONST_VAL array. The following rules are used to get default | |
257 | values: | |
01406fc0 | 258 | |
88dbf20f | 259 | 1- Global and static variables that are declared constant are |
260 | considered CONSTANT. | |
261 | ||
262 | 2- Any other value is considered UNDEFINED. This is useful when | |
41511585 | 263 | considering PHI nodes. PHI arguments that are undefined do not |
264 | change the constant value of the PHI node, which allows for more | |
88dbf20f | 265 | constants to be propagated. |
4ee9c684 | 266 | |
8883e700 | 267 | 3- Variables defined by statements other than assignments and PHI |
88dbf20f | 268 | nodes are considered VARYING. |
4ee9c684 | 269 | |
8883e700 | 270 | 4- Initial values of variables that are not GIMPLE registers are |
bfa30570 | 271 | considered VARYING. */ |
4ee9c684 | 272 | |
88dbf20f | 273 | static prop_value_t |
274 | get_default_value (tree var) | |
275 | { | |
e913b5cd | 276 | prop_value_t val = { UNINITIALIZED, NULL_TREE, 0 }; |
8edeb88b | 277 | gimple stmt; |
278 | ||
279 | stmt = SSA_NAME_DEF_STMT (var); | |
280 | ||
281 | if (gimple_nop_p (stmt)) | |
4ee9c684 | 282 | { |
8edeb88b | 283 | /* Variables defined by an empty statement are those used |
284 | before being initialized. If VAR is a local variable, we | |
285 | can assume initially that it is UNDEFINED, otherwise we must | |
286 | consider it VARYING. */ | |
7c782c9b | 287 | if (!virtual_operand_p (var) |
288 | && TREE_CODE (SSA_NAME_VAR (var)) == VAR_DECL) | |
8edeb88b | 289 | val.lattice_val = UNDEFINED; |
290 | else | |
b7e55469 | 291 | { |
292 | val.lattice_val = VARYING; | |
e913b5cd | 293 | val.mask = -1; |
fc08b993 | 294 | if (flag_tree_bit_ccp) |
295 | { | |
9c1be15e | 296 | wide_int nonzero_bits = get_nonzero_bits (var); |
297 | if (nonzero_bits != -1) | |
fc08b993 | 298 | { |
299 | val.lattice_val = CONSTANT; | |
300 | val.value = build_zero_cst (TREE_TYPE (var)); | |
9c1be15e | 301 | val.mask = extend_mask (nonzero_bits); |
fc08b993 | 302 | } |
303 | } | |
b7e55469 | 304 | } |
4ee9c684 | 305 | } |
b45b214a | 306 | else if (is_gimple_assign (stmt)) |
41511585 | 307 | { |
8edeb88b | 308 | tree cst; |
309 | if (gimple_assign_single_p (stmt) | |
310 | && DECL_P (gimple_assign_rhs1 (stmt)) | |
311 | && (cst = get_symbol_constant_value (gimple_assign_rhs1 (stmt)))) | |
88dbf20f | 312 | { |
8edeb88b | 313 | val.lattice_val = CONSTANT; |
314 | val.value = cst; | |
88dbf20f | 315 | } |
316 | else | |
b45b214a | 317 | { |
318 | /* Any other variable defined by an assignment is considered | |
319 | UNDEFINED. */ | |
320 | val.lattice_val = UNDEFINED; | |
321 | } | |
322 | } | |
323 | else if ((is_gimple_call (stmt) | |
324 | && gimple_call_lhs (stmt) != NULL_TREE) | |
325 | || gimple_code (stmt) == GIMPLE_PHI) | |
326 | { | |
327 | /* A variable defined by a call or a PHI node is considered | |
328 | UNDEFINED. */ | |
329 | val.lattice_val = UNDEFINED; | |
8edeb88b | 330 | } |
331 | else | |
332 | { | |
333 | /* Otherwise, VAR will never take on a constant value. */ | |
334 | val.lattice_val = VARYING; | |
e913b5cd | 335 | val.mask = -1; |
41511585 | 336 | } |
4ee9c684 | 337 | |
41511585 | 338 | return val; |
339 | } | |
4ee9c684 | 340 | |
4ee9c684 | 341 | |
bfa30570 | 342 | /* Get the constant value associated with variable VAR. */ |
4ee9c684 | 343 | |
bfa30570 | 344 | static inline prop_value_t * |
345 | get_value (tree var) | |
88dbf20f | 346 | { |
e004838d | 347 | prop_value_t *val; |
bfa30570 | 348 | |
285df01b | 349 | if (const_val == NULL |
350 | || SSA_NAME_VERSION (var) >= n_const_val) | |
e004838d | 351 | return NULL; |
352 | ||
353 | val = &const_val[SSA_NAME_VERSION (var)]; | |
bfa30570 | 354 | if (val->lattice_val == UNINITIALIZED) |
4ee9c684 | 355 | *val = get_default_value (var); |
356 | ||
f5faab84 | 357 | canonicalize_value (val); |
4af351a8 | 358 | |
4ee9c684 | 359 | return val; |
360 | } | |
361 | ||
15d138c9 | 362 | /* Return the constant tree value associated with VAR. */ |
363 | ||
364 | static inline tree | |
365 | get_constant_value (tree var) | |
366 | { | |
98d92e3c | 367 | prop_value_t *val; |
368 | if (TREE_CODE (var) != SSA_NAME) | |
369 | { | |
370 | if (is_gimple_min_invariant (var)) | |
371 | return var; | |
372 | return NULL_TREE; | |
373 | } | |
374 | val = get_value (var); | |
b7e55469 | 375 | if (val |
376 | && val->lattice_val == CONSTANT | |
377 | && (TREE_CODE (val->value) != INTEGER_CST | |
796b6678 | 378 | || val->mask == 0)) |
15d138c9 | 379 | return val->value; |
380 | return NULL_TREE; | |
381 | } | |
382 | ||
bfa30570 | 383 | /* Sets the value associated with VAR to VARYING. */ |
384 | ||
385 | static inline void | |
386 | set_value_varying (tree var) | |
387 | { | |
388 | prop_value_t *val = &const_val[SSA_NAME_VERSION (var)]; | |
389 | ||
390 | val->lattice_val = VARYING; | |
391 | val->value = NULL_TREE; | |
e913b5cd | 392 | val->mask = -1; |
bfa30570 | 393 | } |
4ee9c684 | 394 | |
b31eb493 | 395 | /* For float types, modify the value of VAL to make ccp work correctly |
396 | for non-standard values (-0, NaN): | |
397 | ||
398 | If HONOR_SIGNED_ZEROS is false, and VAL = -0, we canonicalize it to 0. | |
399 | If HONOR_NANS is false, and VAL is NaN, we canonicalize it to UNDEFINED. | |
400 | This is to fix the following problem (see PR 29921): Suppose we have | |
401 | ||
402 | x = 0.0 * y | |
403 | ||
404 | and we set value of y to NaN. This causes value of x to be set to NaN. | |
405 | When we later determine that y is in fact VARYING, fold uses the fact | |
406 | that HONOR_NANS is false, and we try to change the value of x to 0, | |
407 | causing an ICE. With HONOR_NANS being false, the real appearance of | |
408 | NaN would cause undefined behavior, though, so claiming that y (and x) | |
f5faab84 | 409 | are UNDEFINED initially is correct. |
410 | ||
411 | For other constants, make sure to drop TREE_OVERFLOW. */ | |
b31eb493 | 412 | |
413 | static void | |
f5faab84 | 414 | canonicalize_value (prop_value_t *val) |
b31eb493 | 415 | { |
416 | enum machine_mode mode; | |
417 | tree type; | |
418 | REAL_VALUE_TYPE d; | |
419 | ||
f5faab84 | 420 | if (val->lattice_val != CONSTANT) |
421 | return; | |
422 | ||
423 | if (TREE_OVERFLOW_P (val->value)) | |
424 | val->value = drop_tree_overflow (val->value); | |
425 | ||
426 | if (TREE_CODE (val->value) != REAL_CST) | |
b31eb493 | 427 | return; |
428 | ||
429 | d = TREE_REAL_CST (val->value); | |
430 | type = TREE_TYPE (val->value); | |
431 | mode = TYPE_MODE (type); | |
432 | ||
433 | if (!HONOR_SIGNED_ZEROS (mode) | |
434 | && REAL_VALUE_MINUS_ZERO (d)) | |
435 | { | |
436 | val->value = build_real (type, dconst0); | |
437 | return; | |
438 | } | |
439 | ||
440 | if (!HONOR_NANS (mode) | |
441 | && REAL_VALUE_ISNAN (d)) | |
442 | { | |
443 | val->lattice_val = UNDEFINED; | |
444 | val->value = NULL; | |
b31eb493 | 445 | return; |
446 | } | |
447 | } | |
448 | ||
b7e55469 | 449 | /* Return whether the lattice transition is valid. */ |
450 | ||
451 | static bool | |
452 | valid_lattice_transition (prop_value_t old_val, prop_value_t new_val) | |
453 | { | |
454 | /* Lattice transitions must always be monotonically increasing in | |
455 | value. */ | |
456 | if (old_val.lattice_val < new_val.lattice_val) | |
457 | return true; | |
458 | ||
459 | if (old_val.lattice_val != new_val.lattice_val) | |
460 | return false; | |
461 | ||
462 | if (!old_val.value && !new_val.value) | |
463 | return true; | |
464 | ||
465 | /* Now both lattice values are CONSTANT. */ | |
466 | ||
43c92e0a | 467 | /* Allow transitioning from PHI <&x, not executable> == &x |
468 | to PHI <&x, &y> == common alignment. */ | |
b7e55469 | 469 | if (TREE_CODE (old_val.value) != INTEGER_CST |
470 | && TREE_CODE (new_val.value) == INTEGER_CST) | |
471 | return true; | |
472 | ||
473 | /* Bit-lattices have to agree in the still valid bits. */ | |
474 | if (TREE_CODE (old_val.value) == INTEGER_CST | |
475 | && TREE_CODE (new_val.value) == INTEGER_CST) | |
5de9d3ed | 476 | return (wi::bit_and_not (wi::to_widest (old_val.value), new_val.mask) |
477 | == wi::bit_and_not (wi::to_widest (new_val.value), new_val.mask)); | |
b7e55469 | 478 | |
479 | /* Otherwise constant values have to agree. */ | |
480 | return operand_equal_p (old_val.value, new_val.value, 0); | |
481 | } | |
482 | ||
88dbf20f | 483 | /* Set the value for variable VAR to NEW_VAL. Return true if the new |
484 | value is different from VAR's previous value. */ | |
4ee9c684 | 485 | |
41511585 | 486 | static bool |
88dbf20f | 487 | set_lattice_value (tree var, prop_value_t new_val) |
4ee9c684 | 488 | { |
6d0bf6d6 | 489 | /* We can deal with old UNINITIALIZED values just fine here. */ |
490 | prop_value_t *old_val = &const_val[SSA_NAME_VERSION (var)]; | |
88dbf20f | 491 | |
f5faab84 | 492 | canonicalize_value (&new_val); |
b31eb493 | 493 | |
b7e55469 | 494 | /* We have to be careful to not go up the bitwise lattice |
495 | represented by the mask. | |
496 | ??? This doesn't seem to be the best place to enforce this. */ | |
497 | if (new_val.lattice_val == CONSTANT | |
498 | && old_val->lattice_val == CONSTANT | |
499 | && TREE_CODE (new_val.value) == INTEGER_CST | |
500 | && TREE_CODE (old_val->value) == INTEGER_CST) | |
501 | { | |
5de9d3ed | 502 | widest_int diff = (wi::to_widest (new_val.value) |
503 | ^ wi::to_widest (old_val->value)); | |
cf8f0e63 | 504 | new_val.mask = new_val.mask | old_val->mask | diff; |
b7e55469 | 505 | } |
bfa30570 | 506 | |
b7e55469 | 507 | gcc_assert (valid_lattice_transition (*old_val, new_val)); |
88dbf20f | 508 | |
b7e55469 | 509 | /* If *OLD_VAL and NEW_VAL are the same, return false to inform the |
510 | caller that this was a non-transition. */ | |
511 | if (old_val->lattice_val != new_val.lattice_val | |
512 | || (new_val.lattice_val == CONSTANT | |
513 | && TREE_CODE (new_val.value) == INTEGER_CST | |
514 | && (TREE_CODE (old_val->value) != INTEGER_CST | |
3a54beaf | 515 | || new_val.mask != old_val->mask))) |
4ee9c684 | 516 | { |
b7e55469 | 517 | /* ??? We would like to delay creation of INTEGER_CSTs from |
518 | partially constants here. */ | |
519 | ||
41511585 | 520 | if (dump_file && (dump_flags & TDF_DETAILS)) |
521 | { | |
88dbf20f | 522 | dump_lattice_value (dump_file, "Lattice value changed to ", new_val); |
bfa30570 | 523 | fprintf (dump_file, ". Adding SSA edges to worklist.\n"); |
41511585 | 524 | } |
525 | ||
88dbf20f | 526 | *old_val = new_val; |
527 | ||
6d0bf6d6 | 528 | gcc_assert (new_val.lattice_val != UNINITIALIZED); |
bfa30570 | 529 | return true; |
4ee9c684 | 530 | } |
41511585 | 531 | |
532 | return false; | |
4ee9c684 | 533 | } |
534 | ||
b7e55469 | 535 | static prop_value_t get_value_for_expr (tree, bool); |
536 | static prop_value_t bit_value_binop (enum tree_code, tree, tree, tree); | |
5de9d3ed | 537 | static void bit_value_binop_1 (enum tree_code, tree, widest_int *, widest_int *, |
10c3fe8d | 538 | tree, const widest_int &, const widest_int &, |
539 | tree, const widest_int &, const widest_int &); | |
b7e55469 | 540 | |
5de9d3ed | 541 | /* Return a widest_int that can be used for bitwise simplifications |
b7e55469 | 542 | from VAL. */ |
543 | ||
5de9d3ed | 544 | static widest_int |
e913b5cd | 545 | value_to_wide_int (prop_value_t val) |
b7e55469 | 546 | { |
547 | if (val.value | |
548 | && TREE_CODE (val.value) == INTEGER_CST) | |
5de9d3ed | 549 | return wi::to_widest (val.value); |
e913b5cd | 550 | |
551 | return 0; | |
b7e55469 | 552 | } |
553 | ||
554 | /* Return the value for the address expression EXPR based on alignment | |
555 | information. */ | |
6d0bf6d6 | 556 | |
557 | static prop_value_t | |
b7e55469 | 558 | get_value_from_alignment (tree expr) |
559 | { | |
f8abb542 | 560 | tree type = TREE_TYPE (expr); |
b7e55469 | 561 | prop_value_t val; |
f8abb542 | 562 | unsigned HOST_WIDE_INT bitpos; |
563 | unsigned int align; | |
b7e55469 | 564 | |
565 | gcc_assert (TREE_CODE (expr) == ADDR_EXPR); | |
566 | ||
59da1bcd | 567 | get_pointer_alignment_1 (expr, &align, &bitpos); |
cf8f0e63 | 568 | val.mask = (POINTER_TYPE_P (type) || TYPE_UNSIGNED (type) |
5de9d3ed | 569 | ? wi::mask <widest_int> (TYPE_PRECISION (type), false) |
e913b5cd | 570 | : -1).and_not (align / BITS_PER_UNIT - 1); |
796b6678 | 571 | val.lattice_val = val.mask == -1 ? VARYING : CONSTANT; |
f8abb542 | 572 | if (val.lattice_val == CONSTANT) |
796b6678 | 573 | val.value = build_int_cstu (type, bitpos / BITS_PER_UNIT); |
b7e55469 | 574 | else |
f8abb542 | 575 | val.value = NULL_TREE; |
b7e55469 | 576 | |
577 | return val; | |
578 | } | |
579 | ||
580 | /* Return the value for the tree operand EXPR. If FOR_BITS_P is true | |
581 | return constant bits extracted from alignment information for | |
582 | invariant addresses. */ | |
583 | ||
584 | static prop_value_t | |
585 | get_value_for_expr (tree expr, bool for_bits_p) | |
6d0bf6d6 | 586 | { |
587 | prop_value_t val; | |
588 | ||
589 | if (TREE_CODE (expr) == SSA_NAME) | |
b7e55469 | 590 | { |
591 | val = *get_value (expr); | |
592 | if (for_bits_p | |
593 | && val.lattice_val == CONSTANT | |
594 | && TREE_CODE (val.value) == ADDR_EXPR) | |
595 | val = get_value_from_alignment (val.value); | |
596 | } | |
597 | else if (is_gimple_min_invariant (expr) | |
598 | && (!for_bits_p || TREE_CODE (expr) != ADDR_EXPR)) | |
6d0bf6d6 | 599 | { |
600 | val.lattice_val = CONSTANT; | |
601 | val.value = expr; | |
e913b5cd | 602 | val.mask = 0; |
f5faab84 | 603 | canonicalize_value (&val); |
6d0bf6d6 | 604 | } |
b7e55469 | 605 | else if (TREE_CODE (expr) == ADDR_EXPR) |
606 | val = get_value_from_alignment (expr); | |
6d0bf6d6 | 607 | else |
608 | { | |
609 | val.lattice_val = VARYING; | |
e913b5cd | 610 | val.mask = 1; |
6d0bf6d6 | 611 | val.value = NULL_TREE; |
612 | } | |
6d0bf6d6 | 613 | return val; |
614 | } | |
615 | ||
88dbf20f | 616 | /* Return the likely CCP lattice value for STMT. |
4ee9c684 | 617 | |
41511585 | 618 | If STMT has no operands, then return CONSTANT. |
4ee9c684 | 619 | |
d61b9af3 | 620 | Else if undefinedness of operands of STMT cause its value to be |
621 | undefined, then return UNDEFINED. | |
4ee9c684 | 622 | |
41511585 | 623 | Else if any operands of STMT are constants, then return CONSTANT. |
4ee9c684 | 624 | |
41511585 | 625 | Else return VARYING. */ |
4ee9c684 | 626 | |
88dbf20f | 627 | static ccp_lattice_t |
75a70cf9 | 628 | likely_value (gimple stmt) |
41511585 | 629 | { |
d61b9af3 | 630 | bool has_constant_operand, has_undefined_operand, all_undefined_operands; |
41511585 | 631 | tree use; |
632 | ssa_op_iter iter; | |
8edeb88b | 633 | unsigned i; |
4ee9c684 | 634 | |
590c3166 | 635 | enum gimple_code code = gimple_code (stmt); |
75a70cf9 | 636 | |
637 | /* This function appears to be called only for assignments, calls, | |
638 | conditionals, and switches, due to the logic in visit_stmt. */ | |
639 | gcc_assert (code == GIMPLE_ASSIGN | |
640 | || code == GIMPLE_CALL | |
641 | || code == GIMPLE_COND | |
642 | || code == GIMPLE_SWITCH); | |
88dbf20f | 643 | |
644 | /* If the statement has volatile operands, it won't fold to a | |
645 | constant value. */ | |
75a70cf9 | 646 | if (gimple_has_volatile_ops (stmt)) |
88dbf20f | 647 | return VARYING; |
648 | ||
75a70cf9 | 649 | /* Arrive here for more complex cases. */ |
bfa30570 | 650 | has_constant_operand = false; |
d61b9af3 | 651 | has_undefined_operand = false; |
652 | all_undefined_operands = true; | |
8edeb88b | 653 | FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE) |
41511585 | 654 | { |
bfa30570 | 655 | prop_value_t *val = get_value (use); |
41511585 | 656 | |
bfa30570 | 657 | if (val->lattice_val == UNDEFINED) |
d61b9af3 | 658 | has_undefined_operand = true; |
659 | else | |
660 | all_undefined_operands = false; | |
88dbf20f | 661 | |
41511585 | 662 | if (val->lattice_val == CONSTANT) |
bfa30570 | 663 | has_constant_operand = true; |
4ee9c684 | 664 | } |
41511585 | 665 | |
dd277d48 | 666 | /* There may be constants in regular rhs operands. For calls we |
667 | have to ignore lhs, fndecl and static chain, otherwise only | |
668 | the lhs. */ | |
669 | for (i = (is_gimple_call (stmt) ? 2 : 0) + gimple_has_lhs (stmt); | |
8edeb88b | 670 | i < gimple_num_ops (stmt); ++i) |
671 | { | |
672 | tree op = gimple_op (stmt, i); | |
673 | if (!op || TREE_CODE (op) == SSA_NAME) | |
674 | continue; | |
675 | if (is_gimple_min_invariant (op)) | |
676 | has_constant_operand = true; | |
677 | } | |
678 | ||
87c0a9fc | 679 | if (has_constant_operand) |
680 | all_undefined_operands = false; | |
681 | ||
3d483a94 | 682 | if (has_undefined_operand |
683 | && code == GIMPLE_CALL | |
684 | && gimple_call_internal_p (stmt)) | |
685 | switch (gimple_call_internal_fn (stmt)) | |
686 | { | |
687 | /* These 3 builtins use the first argument just as a magic | |
688 | way how to find out a decl uid. */ | |
689 | case IFN_GOMP_SIMD_LANE: | |
690 | case IFN_GOMP_SIMD_VF: | |
691 | case IFN_GOMP_SIMD_LAST_LANE: | |
692 | has_undefined_operand = false; | |
693 | break; | |
694 | default: | |
695 | break; | |
696 | } | |
697 | ||
d61b9af3 | 698 | /* If the operation combines operands like COMPLEX_EXPR make sure to |
699 | not mark the result UNDEFINED if only one part of the result is | |
700 | undefined. */ | |
75a70cf9 | 701 | if (has_undefined_operand && all_undefined_operands) |
d61b9af3 | 702 | return UNDEFINED; |
75a70cf9 | 703 | else if (code == GIMPLE_ASSIGN && has_undefined_operand) |
d61b9af3 | 704 | { |
75a70cf9 | 705 | switch (gimple_assign_rhs_code (stmt)) |
d61b9af3 | 706 | { |
707 | /* Unary operators are handled with all_undefined_operands. */ | |
708 | case PLUS_EXPR: | |
709 | case MINUS_EXPR: | |
d61b9af3 | 710 | case POINTER_PLUS_EXPR: |
d61b9af3 | 711 | /* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected. |
712 | Not bitwise operators, one VARYING operand may specify the | |
713 | result completely. Not logical operators for the same reason. | |
05a936a0 | 714 | Not COMPLEX_EXPR as one VARYING operand makes the result partly |
715 | not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because | |
716 | the undefined operand may be promoted. */ | |
d61b9af3 | 717 | return UNDEFINED; |
718 | ||
43c92e0a | 719 | case ADDR_EXPR: |
720 | /* If any part of an address is UNDEFINED, like the index | |
721 | of an ARRAY_EXPR, then treat the result as UNDEFINED. */ | |
722 | return UNDEFINED; | |
723 | ||
d61b9af3 | 724 | default: |
725 | ; | |
726 | } | |
727 | } | |
728 | /* If there was an UNDEFINED operand but the result may be not UNDEFINED | |
c91fedc5 | 729 | fall back to CONSTANT. During iteration UNDEFINED may still drop |
730 | to CONSTANT. */ | |
d61b9af3 | 731 | if (has_undefined_operand) |
c91fedc5 | 732 | return CONSTANT; |
d61b9af3 | 733 | |
8edeb88b | 734 | /* We do not consider virtual operands here -- load from read-only |
735 | memory may have only VARYING virtual operands, but still be | |
736 | constant. */ | |
bfa30570 | 737 | if (has_constant_operand |
8edeb88b | 738 | || gimple_references_memory_p (stmt)) |
88dbf20f | 739 | return CONSTANT; |
740 | ||
bfa30570 | 741 | return VARYING; |
4ee9c684 | 742 | } |
743 | ||
bfa30570 | 744 | /* Returns true if STMT cannot be constant. */ |
745 | ||
746 | static bool | |
75a70cf9 | 747 | surely_varying_stmt_p (gimple stmt) |
bfa30570 | 748 | { |
749 | /* If the statement has operands that we cannot handle, it cannot be | |
750 | constant. */ | |
75a70cf9 | 751 | if (gimple_has_volatile_ops (stmt)) |
bfa30570 | 752 | return true; |
753 | ||
f257af64 | 754 | /* If it is a call and does not return a value or is not a |
237e78b1 | 755 | builtin and not an indirect call or a call to function with |
756 | assume_aligned/alloc_align attribute, it is varying. */ | |
75a70cf9 | 757 | if (is_gimple_call (stmt)) |
f257af64 | 758 | { |
237e78b1 | 759 | tree fndecl, fntype = gimple_call_fntype (stmt); |
f257af64 | 760 | if (!gimple_call_lhs (stmt) |
761 | || ((fndecl = gimple_call_fndecl (stmt)) != NULL_TREE | |
237e78b1 | 762 | && !DECL_BUILT_IN (fndecl) |
763 | && !lookup_attribute ("assume_aligned", | |
764 | TYPE_ATTRIBUTES (fntype)) | |
765 | && !lookup_attribute ("alloc_align", | |
766 | TYPE_ATTRIBUTES (fntype)))) | |
f257af64 | 767 | return true; |
768 | } | |
bfa30570 | 769 | |
8edeb88b | 770 | /* Any other store operation is not interesting. */ |
dd277d48 | 771 | else if (gimple_vdef (stmt)) |
8edeb88b | 772 | return true; |
773 | ||
bfa30570 | 774 | /* Anything other than assignments and conditional jumps are not |
775 | interesting for CCP. */ | |
75a70cf9 | 776 | if (gimple_code (stmt) != GIMPLE_ASSIGN |
f257af64 | 777 | && gimple_code (stmt) != GIMPLE_COND |
778 | && gimple_code (stmt) != GIMPLE_SWITCH | |
779 | && gimple_code (stmt) != GIMPLE_CALL) | |
bfa30570 | 780 | return true; |
781 | ||
782 | return false; | |
783 | } | |
4ee9c684 | 784 | |
41511585 | 785 | /* Initialize local data structures for CCP. */ |
4ee9c684 | 786 | |
787 | static void | |
41511585 | 788 | ccp_initialize (void) |
4ee9c684 | 789 | { |
41511585 | 790 | basic_block bb; |
4ee9c684 | 791 | |
285df01b | 792 | n_const_val = num_ssa_names; |
793 | const_val = XCNEWVEC (prop_value_t, n_const_val); | |
4ee9c684 | 794 | |
41511585 | 795 | /* Initialize simulation flags for PHI nodes and statements. */ |
fc00614f | 796 | FOR_EACH_BB_FN (bb, cfun) |
4ee9c684 | 797 | { |
75a70cf9 | 798 | gimple_stmt_iterator i; |
4ee9c684 | 799 | |
75a70cf9 | 800 | for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) |
41511585 | 801 | { |
75a70cf9 | 802 | gimple stmt = gsi_stmt (i); |
2193544e | 803 | bool is_varying; |
804 | ||
805 | /* If the statement is a control insn, then we do not | |
806 | want to avoid simulating the statement once. Failure | |
807 | to do so means that those edges will never get added. */ | |
808 | if (stmt_ends_bb_p (stmt)) | |
809 | is_varying = false; | |
810 | else | |
811 | is_varying = surely_varying_stmt_p (stmt); | |
4ee9c684 | 812 | |
bfa30570 | 813 | if (is_varying) |
41511585 | 814 | { |
88dbf20f | 815 | tree def; |
816 | ssa_op_iter iter; | |
817 | ||
818 | /* If the statement will not produce a constant, mark | |
819 | all its outputs VARYING. */ | |
820 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) | |
8edeb88b | 821 | set_value_varying (def); |
41511585 | 822 | } |
75a70cf9 | 823 | prop_set_simulate_again (stmt, !is_varying); |
41511585 | 824 | } |
4ee9c684 | 825 | } |
826 | ||
75a70cf9 | 827 | /* Now process PHI nodes. We never clear the simulate_again flag on |
828 | phi nodes, since we do not know which edges are executable yet, | |
829 | except for phi nodes for virtual operands when we do not do store ccp. */ | |
fc00614f | 830 | FOR_EACH_BB_FN (bb, cfun) |
4ee9c684 | 831 | { |
75a70cf9 | 832 | gimple_stmt_iterator i; |
41511585 | 833 | |
75a70cf9 | 834 | for (i = gsi_start_phis (bb); !gsi_end_p (i); gsi_next (&i)) |
835 | { | |
836 | gimple phi = gsi_stmt (i); | |
837 | ||
7c782c9b | 838 | if (virtual_operand_p (gimple_phi_result (phi))) |
75a70cf9 | 839 | prop_set_simulate_again (phi, false); |
bfa30570 | 840 | else |
75a70cf9 | 841 | prop_set_simulate_again (phi, true); |
41511585 | 842 | } |
4ee9c684 | 843 | } |
41511585 | 844 | } |
4ee9c684 | 845 | |
43fb76c1 | 846 | /* Debug count support. Reset the values of ssa names |
847 | VARYING when the total number ssa names analyzed is | |
848 | beyond the debug count specified. */ | |
849 | ||
850 | static void | |
851 | do_dbg_cnt (void) | |
852 | { | |
853 | unsigned i; | |
854 | for (i = 0; i < num_ssa_names; i++) | |
855 | { | |
856 | if (!dbg_cnt (ccp)) | |
857 | { | |
858 | const_val[i].lattice_val = VARYING; | |
e913b5cd | 859 | const_val[i].mask = -1; |
43fb76c1 | 860 | const_val[i].value = NULL_TREE; |
861 | } | |
862 | } | |
863 | } | |
864 | ||
4ee9c684 | 865 | |
88dbf20f | 866 | /* Do final substitution of propagated values, cleanup the flowgraph and |
48e1416a | 867 | free allocated storage. |
4ee9c684 | 868 | |
33a34f1e | 869 | Return TRUE when something was optimized. */ |
870 | ||
871 | static bool | |
88dbf20f | 872 | ccp_finalize (void) |
4ee9c684 | 873 | { |
43fb76c1 | 874 | bool something_changed; |
153c3b50 | 875 | unsigned i; |
43fb76c1 | 876 | |
877 | do_dbg_cnt (); | |
153c3b50 | 878 | |
879 | /* Derive alignment and misalignment information from partially | |
fc08b993 | 880 | constant pointers in the lattice or nonzero bits from partially |
881 | constant integers. */ | |
153c3b50 | 882 | for (i = 1; i < num_ssa_names; ++i) |
883 | { | |
884 | tree name = ssa_name (i); | |
885 | prop_value_t *val; | |
153c3b50 | 886 | unsigned int tem, align; |
887 | ||
888 | if (!name | |
fc08b993 | 889 | || (!POINTER_TYPE_P (TREE_TYPE (name)) |
890 | && (!INTEGRAL_TYPE_P (TREE_TYPE (name)) | |
891 | /* Don't record nonzero bits before IPA to avoid | |
892 | using too much memory. */ | |
893 | || first_pass_instance))) | |
153c3b50 | 894 | continue; |
895 | ||
896 | val = get_value (name); | |
897 | if (val->lattice_val != CONSTANT | |
898 | || TREE_CODE (val->value) != INTEGER_CST) | |
899 | continue; | |
900 | ||
fc08b993 | 901 | if (POINTER_TYPE_P (TREE_TYPE (name))) |
902 | { | |
903 | /* Trailing mask bits specify the alignment, trailing value | |
904 | bits the misalignment. */ | |
aeb682a2 | 905 | tem = val->mask.to_uhwi (); |
fc08b993 | 906 | align = (tem & -tem); |
907 | if (align > 1) | |
908 | set_ptr_info_alignment (get_ptr_info (name), align, | |
f9ae6f95 | 909 | (TREE_INT_CST_LOW (val->value) |
fc08b993 | 910 | & (align - 1))); |
911 | } | |
912 | else | |
913 | { | |
9c1be15e | 914 | unsigned int precision = TYPE_PRECISION (TREE_TYPE (val->value)); |
915 | wide_int nonzero_bits = wide_int::from (val->mask, precision, | |
916 | UNSIGNED) | val->value; | |
fc08b993 | 917 | nonzero_bits &= get_nonzero_bits (name); |
918 | set_nonzero_bits (name, nonzero_bits); | |
919 | } | |
153c3b50 | 920 | } |
921 | ||
88dbf20f | 922 | /* Perform substitutions based on the known constant values. */ |
14f101cf | 923 | something_changed = substitute_and_fold (get_constant_value, |
924 | ccp_fold_stmt, true); | |
4ee9c684 | 925 | |
88dbf20f | 926 | free (const_val); |
e004838d | 927 | const_val = NULL; |
33a34f1e | 928 | return something_changed;; |
4ee9c684 | 929 | } |
930 | ||
931 | ||
88dbf20f | 932 | /* Compute the meet operator between *VAL1 and *VAL2. Store the result |
933 | in VAL1. | |
934 | ||
935 | any M UNDEFINED = any | |
88dbf20f | 936 | any M VARYING = VARYING |
937 | Ci M Cj = Ci if (i == j) | |
938 | Ci M Cj = VARYING if (i != j) | |
bfa30570 | 939 | */ |
4ee9c684 | 940 | |
941 | static void | |
88dbf20f | 942 | ccp_lattice_meet (prop_value_t *val1, prop_value_t *val2) |
4ee9c684 | 943 | { |
88dbf20f | 944 | if (val1->lattice_val == UNDEFINED) |
4ee9c684 | 945 | { |
88dbf20f | 946 | /* UNDEFINED M any = any */ |
947 | *val1 = *val2; | |
41511585 | 948 | } |
88dbf20f | 949 | else if (val2->lattice_val == UNDEFINED) |
92481a4d | 950 | { |
88dbf20f | 951 | /* any M UNDEFINED = any |
952 | Nothing to do. VAL1 already contains the value we want. */ | |
953 | ; | |
92481a4d | 954 | } |
88dbf20f | 955 | else if (val1->lattice_val == VARYING |
956 | || val2->lattice_val == VARYING) | |
41511585 | 957 | { |
88dbf20f | 958 | /* any M VARYING = VARYING. */ |
959 | val1->lattice_val = VARYING; | |
e913b5cd | 960 | val1->mask = -1; |
88dbf20f | 961 | val1->value = NULL_TREE; |
41511585 | 962 | } |
b7e55469 | 963 | else if (val1->lattice_val == CONSTANT |
964 | && val2->lattice_val == CONSTANT | |
965 | && TREE_CODE (val1->value) == INTEGER_CST | |
966 | && TREE_CODE (val2->value) == INTEGER_CST) | |
967 | { | |
968 | /* Ci M Cj = Ci if (i == j) | |
969 | Ci M Cj = VARYING if (i != j) | |
970 | ||
971 | For INTEGER_CSTs mask unequal bits. If no equal bits remain, | |
972 | drop to varying. */ | |
e913b5cd | 973 | val1->mask = (val1->mask | val2->mask |
5de9d3ed | 974 | | (wi::to_widest (val1->value) |
975 | ^ wi::to_widest (val2->value))); | |
796b6678 | 976 | if (val1->mask == -1) |
b7e55469 | 977 | { |
978 | val1->lattice_val = VARYING; | |
979 | val1->value = NULL_TREE; | |
980 | } | |
981 | } | |
88dbf20f | 982 | else if (val1->lattice_val == CONSTANT |
983 | && val2->lattice_val == CONSTANT | |
61207d43 | 984 | && simple_cst_equal (val1->value, val2->value) == 1) |
41511585 | 985 | { |
88dbf20f | 986 | /* Ci M Cj = Ci if (i == j) |
987 | Ci M Cj = VARYING if (i != j) | |
988 | ||
b7e55469 | 989 | VAL1 already contains the value we want for equivalent values. */ |
990 | } | |
991 | else if (val1->lattice_val == CONSTANT | |
992 | && val2->lattice_val == CONSTANT | |
993 | && (TREE_CODE (val1->value) == ADDR_EXPR | |
994 | || TREE_CODE (val2->value) == ADDR_EXPR)) | |
995 | { | |
996 | /* When not equal addresses are involved try meeting for | |
997 | alignment. */ | |
998 | prop_value_t tem = *val2; | |
999 | if (TREE_CODE (val1->value) == ADDR_EXPR) | |
1000 | *val1 = get_value_for_expr (val1->value, true); | |
1001 | if (TREE_CODE (val2->value) == ADDR_EXPR) | |
1002 | tem = get_value_for_expr (val2->value, true); | |
1003 | ccp_lattice_meet (val1, &tem); | |
41511585 | 1004 | } |
1005 | else | |
1006 | { | |
88dbf20f | 1007 | /* Any other combination is VARYING. */ |
1008 | val1->lattice_val = VARYING; | |
e913b5cd | 1009 | val1->mask = -1; |
88dbf20f | 1010 | val1->value = NULL_TREE; |
41511585 | 1011 | } |
4ee9c684 | 1012 | } |
1013 | ||
1014 | ||
41511585 | 1015 | /* Loop through the PHI_NODE's parameters for BLOCK and compare their |
1016 | lattice values to determine PHI_NODE's lattice value. The value of a | |
88dbf20f | 1017 | PHI node is determined calling ccp_lattice_meet with all the arguments |
41511585 | 1018 | of the PHI node that are incoming via executable edges. */ |
4ee9c684 | 1019 | |
41511585 | 1020 | static enum ssa_prop_result |
75a70cf9 | 1021 | ccp_visit_phi_node (gimple phi) |
4ee9c684 | 1022 | { |
75a70cf9 | 1023 | unsigned i; |
88dbf20f | 1024 | prop_value_t *old_val, new_val; |
4ee9c684 | 1025 | |
41511585 | 1026 | if (dump_file && (dump_flags & TDF_DETAILS)) |
4ee9c684 | 1027 | { |
41511585 | 1028 | fprintf (dump_file, "\nVisiting PHI node: "); |
75a70cf9 | 1029 | print_gimple_stmt (dump_file, phi, 0, dump_flags); |
4ee9c684 | 1030 | } |
4ee9c684 | 1031 | |
75a70cf9 | 1032 | old_val = get_value (gimple_phi_result (phi)); |
41511585 | 1033 | switch (old_val->lattice_val) |
1034 | { | |
1035 | case VARYING: | |
88dbf20f | 1036 | return SSA_PROP_VARYING; |
4ee9c684 | 1037 | |
41511585 | 1038 | case CONSTANT: |
1039 | new_val = *old_val; | |
1040 | break; | |
4ee9c684 | 1041 | |
41511585 | 1042 | case UNDEFINED: |
41511585 | 1043 | new_val.lattice_val = UNDEFINED; |
88dbf20f | 1044 | new_val.value = NULL_TREE; |
41511585 | 1045 | break; |
4ee9c684 | 1046 | |
41511585 | 1047 | default: |
8c0963c4 | 1048 | gcc_unreachable (); |
41511585 | 1049 | } |
4ee9c684 | 1050 | |
75a70cf9 | 1051 | for (i = 0; i < gimple_phi_num_args (phi); i++) |
41511585 | 1052 | { |
88dbf20f | 1053 | /* Compute the meet operator over all the PHI arguments flowing |
1054 | through executable edges. */ | |
75a70cf9 | 1055 | edge e = gimple_phi_arg_edge (phi, i); |
4ee9c684 | 1056 | |
41511585 | 1057 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1058 | { | |
1059 | fprintf (dump_file, | |
1060 | "\n Argument #%d (%d -> %d %sexecutable)\n", | |
1061 | i, e->src->index, e->dest->index, | |
1062 | (e->flags & EDGE_EXECUTABLE) ? "" : "not "); | |
1063 | } | |
1064 | ||
1065 | /* If the incoming edge is executable, Compute the meet operator for | |
1066 | the existing value of the PHI node and the current PHI argument. */ | |
1067 | if (e->flags & EDGE_EXECUTABLE) | |
1068 | { | |
75a70cf9 | 1069 | tree arg = gimple_phi_arg (phi, i)->def; |
b7e55469 | 1070 | prop_value_t arg_val = get_value_for_expr (arg, false); |
4ee9c684 | 1071 | |
88dbf20f | 1072 | ccp_lattice_meet (&new_val, &arg_val); |
4ee9c684 | 1073 | |
41511585 | 1074 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1075 | { | |
1076 | fprintf (dump_file, "\t"); | |
88dbf20f | 1077 | print_generic_expr (dump_file, arg, dump_flags); |
1078 | dump_lattice_value (dump_file, "\tValue: ", arg_val); | |
41511585 | 1079 | fprintf (dump_file, "\n"); |
1080 | } | |
4ee9c684 | 1081 | |
41511585 | 1082 | if (new_val.lattice_val == VARYING) |
1083 | break; | |
1084 | } | |
1085 | } | |
4ee9c684 | 1086 | |
1087 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
41511585 | 1088 | { |
1089 | dump_lattice_value (dump_file, "\n PHI node value: ", new_val); | |
1090 | fprintf (dump_file, "\n\n"); | |
1091 | } | |
1092 | ||
bfa30570 | 1093 | /* Make the transition to the new value. */ |
75a70cf9 | 1094 | if (set_lattice_value (gimple_phi_result (phi), new_val)) |
41511585 | 1095 | { |
1096 | if (new_val.lattice_val == VARYING) | |
1097 | return SSA_PROP_VARYING; | |
1098 | else | |
1099 | return SSA_PROP_INTERESTING; | |
1100 | } | |
1101 | else | |
1102 | return SSA_PROP_NOT_INTERESTING; | |
4ee9c684 | 1103 | } |
1104 | ||
15d138c9 | 1105 | /* Return the constant value for OP or OP otherwise. */ |
00f4f705 | 1106 | |
1107 | static tree | |
15d138c9 | 1108 | valueize_op (tree op) |
00f4f705 | 1109 | { |
00f4f705 | 1110 | if (TREE_CODE (op) == SSA_NAME) |
1111 | { | |
15d138c9 | 1112 | tree tem = get_constant_value (op); |
1113 | if (tem) | |
1114 | return tem; | |
00f4f705 | 1115 | } |
1116 | return op; | |
1117 | } | |
1118 | ||
41511585 | 1119 | /* CCP specific front-end to the non-destructive constant folding |
1120 | routines. | |
4ee9c684 | 1121 | |
1122 | Attempt to simplify the RHS of STMT knowing that one or more | |
1123 | operands are constants. | |
1124 | ||
1125 | If simplification is possible, return the simplified RHS, | |
75a70cf9 | 1126 | otherwise return the original RHS or NULL_TREE. */ |
4ee9c684 | 1127 | |
1128 | static tree | |
75a70cf9 | 1129 | ccp_fold (gimple stmt) |
4ee9c684 | 1130 | { |
389dd41b | 1131 | location_t loc = gimple_location (stmt); |
75a70cf9 | 1132 | switch (gimple_code (stmt)) |
88dbf20f | 1133 | { |
75a70cf9 | 1134 | case GIMPLE_COND: |
1135 | { | |
1136 | /* Handle comparison operators that can appear in GIMPLE form. */ | |
15d138c9 | 1137 | tree op0 = valueize_op (gimple_cond_lhs (stmt)); |
1138 | tree op1 = valueize_op (gimple_cond_rhs (stmt)); | |
75a70cf9 | 1139 | enum tree_code code = gimple_cond_code (stmt); |
389dd41b | 1140 | return fold_binary_loc (loc, code, boolean_type_node, op0, op1); |
75a70cf9 | 1141 | } |
4ee9c684 | 1142 | |
75a70cf9 | 1143 | case GIMPLE_SWITCH: |
1144 | { | |
15d138c9 | 1145 | /* Return the constant switch index. */ |
1146 | return valueize_op (gimple_switch_index (stmt)); | |
75a70cf9 | 1147 | } |
912f109f | 1148 | |
1d0b727d | 1149 | case GIMPLE_ASSIGN: |
1150 | case GIMPLE_CALL: | |
1151 | return gimple_fold_stmt_to_constant_1 (stmt, valueize_op); | |
04236c3a | 1152 | |
8782adcf | 1153 | default: |
1d0b727d | 1154 | gcc_unreachable (); |
8782adcf | 1155 | } |
8782adcf | 1156 | } |
75a70cf9 | 1157 | |
b7e55469 | 1158 | /* Apply the operation CODE in type TYPE to the value, mask pair |
1159 | RVAL and RMASK representing a value of type RTYPE and set | |
1160 | the value, mask pair *VAL and *MASK to the result. */ | |
1161 | ||
1162 | static void | |
1163 | bit_value_unop_1 (enum tree_code code, tree type, | |
5de9d3ed | 1164 | widest_int *val, widest_int *mask, |
1165 | tree rtype, const widest_int &rval, const widest_int &rmask) | |
b7e55469 | 1166 | { |
1167 | switch (code) | |
1168 | { | |
1169 | case BIT_NOT_EXPR: | |
1170 | *mask = rmask; | |
cf8f0e63 | 1171 | *val = ~rval; |
b7e55469 | 1172 | break; |
1173 | ||
1174 | case NEGATE_EXPR: | |
1175 | { | |
5de9d3ed | 1176 | widest_int temv, temm; |
b7e55469 | 1177 | /* Return ~rval + 1. */ |
1178 | bit_value_unop_1 (BIT_NOT_EXPR, type, &temv, &temm, type, rval, rmask); | |
1179 | bit_value_binop_1 (PLUS_EXPR, type, val, mask, | |
e913b5cd | 1180 | type, temv, temm, type, 1, 0); |
b7e55469 | 1181 | break; |
1182 | } | |
1183 | ||
1184 | CASE_CONVERT: | |
1185 | { | |
e913b5cd | 1186 | signop sgn; |
b7e55469 | 1187 | |
1188 | /* First extend mask and value according to the original type. */ | |
e913b5cd | 1189 | sgn = TYPE_SIGN (rtype); |
796b6678 | 1190 | *mask = wi::ext (rmask, TYPE_PRECISION (rtype), sgn); |
1191 | *val = wi::ext (rval, TYPE_PRECISION (rtype), sgn); | |
b7e55469 | 1192 | |
1193 | /* Then extend mask and value according to the target type. */ | |
e913b5cd | 1194 | sgn = TYPE_SIGN (type); |
796b6678 | 1195 | *mask = wi::ext (*mask, TYPE_PRECISION (type), sgn); |
1196 | *val = wi::ext (*val, TYPE_PRECISION (type), sgn); | |
b7e55469 | 1197 | break; |
1198 | } | |
1199 | ||
1200 | default: | |
e913b5cd | 1201 | *mask = -1; |
b7e55469 | 1202 | break; |
1203 | } | |
1204 | } | |
1205 | ||
1206 | /* Apply the operation CODE in type TYPE to the value, mask pairs | |
1207 | R1VAL, R1MASK and R2VAL, R2MASK representing a values of type R1TYPE | |
1208 | and R2TYPE and set the value, mask pair *VAL and *MASK to the result. */ | |
1209 | ||
1210 | static void | |
1211 | bit_value_binop_1 (enum tree_code code, tree type, | |
5de9d3ed | 1212 | widest_int *val, widest_int *mask, |
10c3fe8d | 1213 | tree r1type, const widest_int &r1val, |
1214 | const widest_int &r1mask, tree r2type, | |
1215 | const widest_int &r2val, const widest_int &r2mask) | |
b7e55469 | 1216 | { |
e913b5cd | 1217 | signop sgn = TYPE_SIGN (type); |
1218 | int width = TYPE_PRECISION (type); | |
10c3fe8d | 1219 | bool swap_p = false; |
e913b5cd | 1220 | |
1221 | /* Assume we'll get a constant result. Use an initial non varying | |
1222 | value, we fall back to varying in the end if necessary. */ | |
1223 | *mask = -1; | |
1224 | ||
b7e55469 | 1225 | switch (code) |
1226 | { | |
1227 | case BIT_AND_EXPR: | |
1228 | /* The mask is constant where there is a known not | |
1229 | set bit, (m1 | m2) & ((v1 | m1) & (v2 | m2)) */ | |
cf8f0e63 | 1230 | *mask = (r1mask | r2mask) & (r1val | r1mask) & (r2val | r2mask); |
1231 | *val = r1val & r2val; | |
b7e55469 | 1232 | break; |
1233 | ||
1234 | case BIT_IOR_EXPR: | |
1235 | /* The mask is constant where there is a known | |
1236 | set bit, (m1 | m2) & ~((v1 & ~m1) | (v2 & ~m2)). */ | |
cf8f0e63 | 1237 | *mask = (r1mask | r2mask) |
1238 | .and_not (r1val.and_not (r1mask) | r2val.and_not (r2mask)); | |
1239 | *val = r1val | r2val; | |
b7e55469 | 1240 | break; |
1241 | ||
1242 | case BIT_XOR_EXPR: | |
1243 | /* m1 | m2 */ | |
cf8f0e63 | 1244 | *mask = r1mask | r2mask; |
1245 | *val = r1val ^ r2val; | |
b7e55469 | 1246 | break; |
1247 | ||
1248 | case LROTATE_EXPR: | |
1249 | case RROTATE_EXPR: | |
796b6678 | 1250 | if (r2mask == 0) |
b7e55469 | 1251 | { |
e913b5cd | 1252 | wide_int shift = r2val; |
796b6678 | 1253 | if (shift == 0) |
e913b5cd | 1254 | { |
1255 | *mask = r1mask; | |
1256 | *val = r1val; | |
1257 | } | |
ddb1be65 | 1258 | else |
e913b5cd | 1259 | { |
796b6678 | 1260 | if (wi::neg_p (shift)) |
e913b5cd | 1261 | { |
1262 | shift = -shift; | |
1263 | if (code == RROTATE_EXPR) | |
1264 | code = LROTATE_EXPR; | |
1265 | else | |
1266 | code = RROTATE_EXPR; | |
1267 | } | |
1268 | if (code == RROTATE_EXPR) | |
1269 | { | |
796b6678 | 1270 | *mask = wi::rrotate (r1mask, shift, width); |
1271 | *val = wi::rrotate (r1val, shift, width); | |
e913b5cd | 1272 | } |
1273 | else | |
1274 | { | |
796b6678 | 1275 | *mask = wi::lrotate (r1mask, shift, width); |
1276 | *val = wi::lrotate (r1val, shift, width); | |
e913b5cd | 1277 | } |
1278 | } | |
b7e55469 | 1279 | } |
1280 | break; | |
1281 | ||
1282 | case LSHIFT_EXPR: | |
1283 | case RSHIFT_EXPR: | |
1284 | /* ??? We can handle partially known shift counts if we know | |
1285 | its sign. That way we can tell that (x << (y | 8)) & 255 | |
1286 | is zero. */ | |
796b6678 | 1287 | if (r2mask == 0) |
b7e55469 | 1288 | { |
e913b5cd | 1289 | wide_int shift = r2val; |
796b6678 | 1290 | if (shift == 0) |
b7e55469 | 1291 | { |
1292 | *mask = r1mask; | |
1293 | *val = r1val; | |
1294 | } | |
ddb1be65 | 1295 | else |
e913b5cd | 1296 | { |
796b6678 | 1297 | if (wi::neg_p (shift)) |
e913b5cd | 1298 | { |
1299 | shift = -shift; | |
1300 | if (code == RSHIFT_EXPR) | |
1301 | code = LSHIFT_EXPR; | |
1302 | else | |
1303 | code = RSHIFT_EXPR; | |
1304 | } | |
1305 | if (code == RSHIFT_EXPR) | |
1306 | { | |
45639915 | 1307 | *mask = wi::rshift (wi::ext (r1mask, width, sgn), shift, sgn); |
1308 | *val = wi::rshift (wi::ext (r1val, width, sgn), shift, sgn); | |
e913b5cd | 1309 | } |
1310 | else | |
1311 | { | |
45639915 | 1312 | *mask = wi::ext (wi::lshift (r1mask, shift), width, sgn); |
1313 | *val = wi::ext (wi::lshift (r1val, shift), width, sgn); | |
e913b5cd | 1314 | } |
1315 | } | |
b7e55469 | 1316 | } |
1317 | break; | |
1318 | ||
1319 | case PLUS_EXPR: | |
1320 | case POINTER_PLUS_EXPR: | |
1321 | { | |
b7e55469 | 1322 | /* Do the addition with unknown bits set to zero, to give carry-ins of |
1323 | zero wherever possible. */ | |
ab2c1de8 | 1324 | widest_int lo = r1val.and_not (r1mask) + r2val.and_not (r2mask); |
796b6678 | 1325 | lo = wi::ext (lo, width, sgn); |
b7e55469 | 1326 | /* Do the addition with unknown bits set to one, to give carry-ins of |
1327 | one wherever possible. */ | |
ab2c1de8 | 1328 | widest_int hi = (r1val | r1mask) + (r2val | r2mask); |
796b6678 | 1329 | hi = wi::ext (hi, width, sgn); |
b7e55469 | 1330 | /* Each bit in the result is known if (a) the corresponding bits in |
1331 | both inputs are known, and (b) the carry-in to that bit position | |
1332 | is known. We can check condition (b) by seeing if we got the same | |
1333 | result with minimised carries as with maximised carries. */ | |
cf8f0e63 | 1334 | *mask = r1mask | r2mask | (lo ^ hi); |
796b6678 | 1335 | *mask = wi::ext (*mask, width, sgn); |
b7e55469 | 1336 | /* It shouldn't matter whether we choose lo or hi here. */ |
1337 | *val = lo; | |
1338 | break; | |
1339 | } | |
1340 | ||
1341 | case MINUS_EXPR: | |
1342 | { | |
5de9d3ed | 1343 | widest_int temv, temm; |
b7e55469 | 1344 | bit_value_unop_1 (NEGATE_EXPR, r2type, &temv, &temm, |
1345 | r2type, r2val, r2mask); | |
1346 | bit_value_binop_1 (PLUS_EXPR, type, val, mask, | |
1347 | r1type, r1val, r1mask, | |
1348 | r2type, temv, temm); | |
1349 | break; | |
1350 | } | |
1351 | ||
1352 | case MULT_EXPR: | |
1353 | { | |
1354 | /* Just track trailing zeros in both operands and transfer | |
1355 | them to the other. */ | |
796b6678 | 1356 | int r1tz = wi::ctz (r1val | r1mask); |
1357 | int r2tz = wi::ctz (r2val | r2mask); | |
e913b5cd | 1358 | if (r1tz + r2tz >= width) |
b7e55469 | 1359 | { |
e913b5cd | 1360 | *mask = 0; |
1361 | *val = 0; | |
b7e55469 | 1362 | } |
1363 | else if (r1tz + r2tz > 0) | |
1364 | { | |
5de9d3ed | 1365 | *mask = wi::ext (wi::mask <widest_int> (r1tz + r2tz, true), |
796b6678 | 1366 | width, sgn); |
e913b5cd | 1367 | *val = 0; |
b7e55469 | 1368 | } |
1369 | break; | |
1370 | } | |
1371 | ||
1372 | case EQ_EXPR: | |
1373 | case NE_EXPR: | |
1374 | { | |
5de9d3ed | 1375 | widest_int m = r1mask | r2mask; |
cf8f0e63 | 1376 | if (r1val.and_not (m) != r2val.and_not (m)) |
b7e55469 | 1377 | { |
e913b5cd | 1378 | *mask = 0; |
1379 | *val = ((code == EQ_EXPR) ? 0 : 1); | |
b7e55469 | 1380 | } |
1381 | else | |
1382 | { | |
1383 | /* We know the result of a comparison is always one or zero. */ | |
e913b5cd | 1384 | *mask = 1; |
1385 | *val = 0; | |
b7e55469 | 1386 | } |
1387 | break; | |
1388 | } | |
1389 | ||
1390 | case GE_EXPR: | |
1391 | case GT_EXPR: | |
10c3fe8d | 1392 | swap_p = true; |
1393 | code = swap_tree_comparison (code); | |
1394 | /* Fall through. */ | |
b7e55469 | 1395 | case LT_EXPR: |
1396 | case LE_EXPR: | |
1397 | { | |
1398 | int minmax, maxmin; | |
e913b5cd | 1399 | |
10c3fe8d | 1400 | const widest_int &o1val = swap_p ? r2val : r1val; |
1401 | const widest_int &o1mask = swap_p ? r2mask : r1mask; | |
1402 | const widest_int &o2val = swap_p ? r1val : r2val; | |
1403 | const widest_int &o2mask = swap_p ? r1mask : r2mask; | |
1404 | ||
b7e55469 | 1405 | /* If the most significant bits are not known we know nothing. */ |
796b6678 | 1406 | if (wi::neg_p (o1mask) || wi::neg_p (o2mask)) |
b7e55469 | 1407 | break; |
1408 | ||
90c0f5b7 | 1409 | /* For comparisons the signedness is in the comparison operands. */ |
e913b5cd | 1410 | sgn = TYPE_SIGN (r1type); |
90c0f5b7 | 1411 | |
b7e55469 | 1412 | /* If we know the most significant bits we know the values |
1413 | value ranges by means of treating varying bits as zero | |
1414 | or one. Do a cross comparison of the max/min pairs. */ | |
796b6678 | 1415 | maxmin = wi::cmp (o1val | o1mask, o2val.and_not (o2mask), sgn); |
1416 | minmax = wi::cmp (o1val.and_not (o1mask), o2val | o2mask, sgn); | |
e913b5cd | 1417 | if (maxmin < 0) /* o1 is less than o2. */ |
b7e55469 | 1418 | { |
e913b5cd | 1419 | *mask = 0; |
1420 | *val = 1; | |
b7e55469 | 1421 | } |
e913b5cd | 1422 | else if (minmax > 0) /* o1 is not less or equal to o2. */ |
b7e55469 | 1423 | { |
e913b5cd | 1424 | *mask = 0; |
1425 | *val = 0; | |
b7e55469 | 1426 | } |
e913b5cd | 1427 | else if (maxmin == minmax) /* o1 and o2 are equal. */ |
b7e55469 | 1428 | { |
1429 | /* This probably should never happen as we'd have | |
1430 | folded the thing during fully constant value folding. */ | |
e913b5cd | 1431 | *mask = 0; |
1432 | *val = (code == LE_EXPR ? 1 : 0); | |
b7e55469 | 1433 | } |
1434 | else | |
1435 | { | |
1436 | /* We know the result of a comparison is always one or zero. */ | |
e913b5cd | 1437 | *mask = 1; |
1438 | *val = 0; | |
b7e55469 | 1439 | } |
1440 | break; | |
1441 | } | |
1442 | ||
1443 | default:; | |
1444 | } | |
1445 | } | |
1446 | ||
1447 | /* Return the propagation value when applying the operation CODE to | |
1448 | the value RHS yielding type TYPE. */ | |
1449 | ||
1450 | static prop_value_t | |
1451 | bit_value_unop (enum tree_code code, tree type, tree rhs) | |
1452 | { | |
1453 | prop_value_t rval = get_value_for_expr (rhs, true); | |
5de9d3ed | 1454 | widest_int value, mask; |
b7e55469 | 1455 | prop_value_t val; |
c91fedc5 | 1456 | |
1457 | if (rval.lattice_val == UNDEFINED) | |
1458 | return rval; | |
1459 | ||
b7e55469 | 1460 | gcc_assert ((rval.lattice_val == CONSTANT |
1461 | && TREE_CODE (rval.value) == INTEGER_CST) | |
796b6678 | 1462 | || rval.mask == -1); |
b7e55469 | 1463 | bit_value_unop_1 (code, type, &value, &mask, |
e913b5cd | 1464 | TREE_TYPE (rhs), value_to_wide_int (rval), rval.mask); |
796b6678 | 1465 | if (mask != -1) |
b7e55469 | 1466 | { |
1467 | val.lattice_val = CONSTANT; | |
1468 | val.mask = mask; | |
1469 | /* ??? Delay building trees here. */ | |
e913b5cd | 1470 | val.value = wide_int_to_tree (type, value); |
b7e55469 | 1471 | } |
1472 | else | |
1473 | { | |
1474 | val.lattice_val = VARYING; | |
1475 | val.value = NULL_TREE; | |
e913b5cd | 1476 | val.mask = -1; |
b7e55469 | 1477 | } |
1478 | return val; | |
1479 | } | |
1480 | ||
1481 | /* Return the propagation value when applying the operation CODE to | |
1482 | the values RHS1 and RHS2 yielding type TYPE. */ | |
1483 | ||
1484 | static prop_value_t | |
1485 | bit_value_binop (enum tree_code code, tree type, tree rhs1, tree rhs2) | |
1486 | { | |
1487 | prop_value_t r1val = get_value_for_expr (rhs1, true); | |
1488 | prop_value_t r2val = get_value_for_expr (rhs2, true); | |
5de9d3ed | 1489 | widest_int value, mask; |
b7e55469 | 1490 | prop_value_t val; |
c91fedc5 | 1491 | |
1492 | if (r1val.lattice_val == UNDEFINED | |
1493 | || r2val.lattice_val == UNDEFINED) | |
1494 | { | |
1495 | val.lattice_val = VARYING; | |
1496 | val.value = NULL_TREE; | |
e913b5cd | 1497 | val.mask = -1; |
c91fedc5 | 1498 | return val; |
1499 | } | |
1500 | ||
b7e55469 | 1501 | gcc_assert ((r1val.lattice_val == CONSTANT |
1502 | && TREE_CODE (r1val.value) == INTEGER_CST) | |
796b6678 | 1503 | || r1val.mask == -1); |
b7e55469 | 1504 | gcc_assert ((r2val.lattice_val == CONSTANT |
1505 | && TREE_CODE (r2val.value) == INTEGER_CST) | |
796b6678 | 1506 | || r2val.mask == -1); |
b7e55469 | 1507 | bit_value_binop_1 (code, type, &value, &mask, |
e913b5cd | 1508 | TREE_TYPE (rhs1), value_to_wide_int (r1val), r1val.mask, |
1509 | TREE_TYPE (rhs2), value_to_wide_int (r2val), r2val.mask); | |
1510 | if (mask != -1) | |
b7e55469 | 1511 | { |
1512 | val.lattice_val = CONSTANT; | |
1513 | val.mask = mask; | |
1514 | /* ??? Delay building trees here. */ | |
e913b5cd | 1515 | val.value = wide_int_to_tree (type, value); |
b7e55469 | 1516 | } |
1517 | else | |
1518 | { | |
1519 | val.lattice_val = VARYING; | |
1520 | val.value = NULL_TREE; | |
e913b5cd | 1521 | val.mask = -1; |
b7e55469 | 1522 | } |
1523 | return val; | |
1524 | } | |
1525 | ||
237e78b1 | 1526 | /* Return the propagation value for __builtin_assume_aligned |
1527 | and functions with assume_aligned or alloc_aligned attribute. | |
1528 | For __builtin_assume_aligned, ATTR is NULL_TREE, | |
1529 | for assume_aligned attribute ATTR is non-NULL and ALLOC_ALIGNED | |
1530 | is false, for alloc_aligned attribute ATTR is non-NULL and | |
1531 | ALLOC_ALIGNED is true. */ | |
fca0886c | 1532 | |
1533 | static prop_value_t | |
237e78b1 | 1534 | bit_value_assume_aligned (gimple stmt, tree attr, prop_value_t ptrval, |
1535 | bool alloc_aligned) | |
fca0886c | 1536 | { |
237e78b1 | 1537 | tree align, misalign = NULL_TREE, type; |
fca0886c | 1538 | unsigned HOST_WIDE_INT aligni, misaligni = 0; |
fca0886c | 1539 | prop_value_t alignval; |
5de9d3ed | 1540 | widest_int value, mask; |
fca0886c | 1541 | prop_value_t val; |
e913b5cd | 1542 | |
237e78b1 | 1543 | if (attr == NULL_TREE) |
1544 | { | |
1545 | tree ptr = gimple_call_arg (stmt, 0); | |
1546 | type = TREE_TYPE (ptr); | |
1547 | ptrval = get_value_for_expr (ptr, true); | |
1548 | } | |
1549 | else | |
1550 | { | |
1551 | tree lhs = gimple_call_lhs (stmt); | |
1552 | type = TREE_TYPE (lhs); | |
1553 | } | |
1554 | ||
fca0886c | 1555 | if (ptrval.lattice_val == UNDEFINED) |
1556 | return ptrval; | |
1557 | gcc_assert ((ptrval.lattice_val == CONSTANT | |
1558 | && TREE_CODE (ptrval.value) == INTEGER_CST) | |
796b6678 | 1559 | || ptrval.mask == -1); |
237e78b1 | 1560 | if (attr == NULL_TREE) |
fca0886c | 1561 | { |
237e78b1 | 1562 | /* Get aligni and misaligni from __builtin_assume_aligned. */ |
1563 | align = gimple_call_arg (stmt, 1); | |
1564 | if (!tree_fits_uhwi_p (align)) | |
fca0886c | 1565 | return ptrval; |
237e78b1 | 1566 | aligni = tree_to_uhwi (align); |
1567 | if (gimple_call_num_args (stmt) > 2) | |
1568 | { | |
1569 | misalign = gimple_call_arg (stmt, 2); | |
1570 | if (!tree_fits_uhwi_p (misalign)) | |
1571 | return ptrval; | |
1572 | misaligni = tree_to_uhwi (misalign); | |
1573 | } | |
1574 | } | |
1575 | else | |
fca0886c | 1576 | { |
237e78b1 | 1577 | /* Get aligni and misaligni from assume_aligned or |
1578 | alloc_align attributes. */ | |
1579 | if (TREE_VALUE (attr) == NULL_TREE) | |
fca0886c | 1580 | return ptrval; |
237e78b1 | 1581 | attr = TREE_VALUE (attr); |
1582 | align = TREE_VALUE (attr); | |
1583 | if (!tree_fits_uhwi_p (align)) | |
fca0886c | 1584 | return ptrval; |
237e78b1 | 1585 | aligni = tree_to_uhwi (align); |
1586 | if (alloc_aligned) | |
1587 | { | |
1588 | if (aligni == 0 || aligni > gimple_call_num_args (stmt)) | |
1589 | return ptrval; | |
1590 | align = gimple_call_arg (stmt, aligni - 1); | |
1591 | if (!tree_fits_uhwi_p (align)) | |
1592 | return ptrval; | |
1593 | aligni = tree_to_uhwi (align); | |
1594 | } | |
1595 | else if (TREE_CHAIN (attr) && TREE_VALUE (TREE_CHAIN (attr))) | |
1596 | { | |
1597 | misalign = TREE_VALUE (TREE_CHAIN (attr)); | |
1598 | if (!tree_fits_uhwi_p (misalign)) | |
1599 | return ptrval; | |
1600 | misaligni = tree_to_uhwi (misalign); | |
1601 | } | |
fca0886c | 1602 | } |
237e78b1 | 1603 | if (aligni <= 1 || (aligni & (aligni - 1)) != 0 || misaligni >= aligni) |
1604 | return ptrval; | |
1605 | ||
fca0886c | 1606 | align = build_int_cst_type (type, -aligni); |
1607 | alignval = get_value_for_expr (align, true); | |
1608 | bit_value_binop_1 (BIT_AND_EXPR, type, &value, &mask, | |
e913b5cd | 1609 | type, value_to_wide_int (ptrval), ptrval.mask, |
1610 | type, value_to_wide_int (alignval), alignval.mask); | |
796b6678 | 1611 | if (mask != -1) |
fca0886c | 1612 | { |
1613 | val.lattice_val = CONSTANT; | |
1614 | val.mask = mask; | |
e913b5cd | 1615 | gcc_assert ((mask.to_uhwi () & (aligni - 1)) == 0); |
1616 | gcc_assert ((value.to_uhwi () & (aligni - 1)) == 0); | |
1617 | value |= misaligni; | |
fca0886c | 1618 | /* ??? Delay building trees here. */ |
e913b5cd | 1619 | val.value = wide_int_to_tree (type, value); |
fca0886c | 1620 | } |
1621 | else | |
1622 | { | |
1623 | val.lattice_val = VARYING; | |
1624 | val.value = NULL_TREE; | |
e913b5cd | 1625 | val.mask = -1; |
fca0886c | 1626 | } |
1627 | return val; | |
1628 | } | |
1629 | ||
75a70cf9 | 1630 | /* Evaluate statement STMT. |
1631 | Valid only for assignments, calls, conditionals, and switches. */ | |
4ee9c684 | 1632 | |
88dbf20f | 1633 | static prop_value_t |
75a70cf9 | 1634 | evaluate_stmt (gimple stmt) |
4ee9c684 | 1635 | { |
88dbf20f | 1636 | prop_value_t val; |
4f61cce6 | 1637 | tree simplified = NULL_TREE; |
88dbf20f | 1638 | ccp_lattice_t likelyvalue = likely_value (stmt); |
b7e55469 | 1639 | bool is_constant = false; |
581bf1c2 | 1640 | unsigned int align; |
88dbf20f | 1641 | |
b7e55469 | 1642 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1643 | { | |
1644 | fprintf (dump_file, "which is likely "); | |
1645 | switch (likelyvalue) | |
1646 | { | |
1647 | case CONSTANT: | |
1648 | fprintf (dump_file, "CONSTANT"); | |
1649 | break; | |
1650 | case UNDEFINED: | |
1651 | fprintf (dump_file, "UNDEFINED"); | |
1652 | break; | |
1653 | case VARYING: | |
1654 | fprintf (dump_file, "VARYING"); | |
1655 | break; | |
1656 | default:; | |
1657 | } | |
1658 | fprintf (dump_file, "\n"); | |
1659 | } | |
add6ee5e | 1660 | |
4ee9c684 | 1661 | /* If the statement is likely to have a CONSTANT result, then try |
1662 | to fold the statement to determine the constant value. */ | |
75a70cf9 | 1663 | /* FIXME. This is the only place that we call ccp_fold. |
1664 | Since likely_value never returns CONSTANT for calls, we will | |
1665 | not attempt to fold them, including builtins that may profit. */ | |
4ee9c684 | 1666 | if (likelyvalue == CONSTANT) |
b7e55469 | 1667 | { |
1668 | fold_defer_overflow_warnings (); | |
1669 | simplified = ccp_fold (stmt); | |
1670 | is_constant = simplified && is_gimple_min_invariant (simplified); | |
1671 | fold_undefer_overflow_warnings (is_constant, stmt, 0); | |
1672 | if (is_constant) | |
1673 | { | |
1674 | /* The statement produced a constant value. */ | |
1675 | val.lattice_val = CONSTANT; | |
1676 | val.value = simplified; | |
e913b5cd | 1677 | val.mask = 0; |
b7e55469 | 1678 | } |
1679 | } | |
4ee9c684 | 1680 | /* If the statement is likely to have a VARYING result, then do not |
1681 | bother folding the statement. */ | |
04236c3a | 1682 | else if (likelyvalue == VARYING) |
75a70cf9 | 1683 | { |
590c3166 | 1684 | enum gimple_code code = gimple_code (stmt); |
75a70cf9 | 1685 | if (code == GIMPLE_ASSIGN) |
1686 | { | |
1687 | enum tree_code subcode = gimple_assign_rhs_code (stmt); | |
48e1416a | 1688 | |
75a70cf9 | 1689 | /* Other cases cannot satisfy is_gimple_min_invariant |
1690 | without folding. */ | |
1691 | if (get_gimple_rhs_class (subcode) == GIMPLE_SINGLE_RHS) | |
1692 | simplified = gimple_assign_rhs1 (stmt); | |
1693 | } | |
1694 | else if (code == GIMPLE_SWITCH) | |
1695 | simplified = gimple_switch_index (stmt); | |
1696 | else | |
a65c4d64 | 1697 | /* These cannot satisfy is_gimple_min_invariant without folding. */ |
1698 | gcc_assert (code == GIMPLE_CALL || code == GIMPLE_COND); | |
b7e55469 | 1699 | is_constant = simplified && is_gimple_min_invariant (simplified); |
1700 | if (is_constant) | |
1701 | { | |
1702 | /* The statement produced a constant value. */ | |
1703 | val.lattice_val = CONSTANT; | |
1704 | val.value = simplified; | |
e913b5cd | 1705 | val.mask = 0; |
b7e55469 | 1706 | } |
75a70cf9 | 1707 | } |
4ee9c684 | 1708 | |
b7e55469 | 1709 | /* Resort to simplification for bitwise tracking. */ |
1710 | if (flag_tree_bit_ccp | |
939514e9 | 1711 | && (likelyvalue == CONSTANT || is_gimple_call (stmt)) |
b7e55469 | 1712 | && !is_constant) |
912f109f | 1713 | { |
b7e55469 | 1714 | enum gimple_code code = gimple_code (stmt); |
1715 | val.lattice_val = VARYING; | |
1716 | val.value = NULL_TREE; | |
e913b5cd | 1717 | val.mask = -1; |
b7e55469 | 1718 | if (code == GIMPLE_ASSIGN) |
912f109f | 1719 | { |
b7e55469 | 1720 | enum tree_code subcode = gimple_assign_rhs_code (stmt); |
1721 | tree rhs1 = gimple_assign_rhs1 (stmt); | |
1722 | switch (get_gimple_rhs_class (subcode)) | |
1723 | { | |
1724 | case GIMPLE_SINGLE_RHS: | |
1725 | if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
1726 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
1727 | val = get_value_for_expr (rhs1, true); | |
1728 | break; | |
1729 | ||
1730 | case GIMPLE_UNARY_RHS: | |
1731 | if ((INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
1732 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
1733 | && (INTEGRAL_TYPE_P (gimple_expr_type (stmt)) | |
1734 | || POINTER_TYPE_P (gimple_expr_type (stmt)))) | |
1735 | val = bit_value_unop (subcode, gimple_expr_type (stmt), rhs1); | |
1736 | break; | |
1737 | ||
1738 | case GIMPLE_BINARY_RHS: | |
1739 | if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
1740 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
1741 | { | |
e47d81e0 | 1742 | tree lhs = gimple_assign_lhs (stmt); |
b7e55469 | 1743 | tree rhs2 = gimple_assign_rhs2 (stmt); |
1744 | val = bit_value_binop (subcode, | |
e47d81e0 | 1745 | TREE_TYPE (lhs), rhs1, rhs2); |
b7e55469 | 1746 | } |
1747 | break; | |
1748 | ||
1749 | default:; | |
1750 | } | |
912f109f | 1751 | } |
b7e55469 | 1752 | else if (code == GIMPLE_COND) |
1753 | { | |
1754 | enum tree_code code = gimple_cond_code (stmt); | |
1755 | tree rhs1 = gimple_cond_lhs (stmt); | |
1756 | tree rhs2 = gimple_cond_rhs (stmt); | |
1757 | if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
1758 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
1759 | val = bit_value_binop (code, TREE_TYPE (rhs1), rhs1, rhs2); | |
1760 | } | |
0b4f0116 | 1761 | else if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)) |
153c3b50 | 1762 | { |
0b4f0116 | 1763 | tree fndecl = gimple_call_fndecl (stmt); |
153c3b50 | 1764 | switch (DECL_FUNCTION_CODE (fndecl)) |
1765 | { | |
1766 | case BUILT_IN_MALLOC: | |
1767 | case BUILT_IN_REALLOC: | |
1768 | case BUILT_IN_CALLOC: | |
939514e9 | 1769 | case BUILT_IN_STRDUP: |
1770 | case BUILT_IN_STRNDUP: | |
153c3b50 | 1771 | val.lattice_val = CONSTANT; |
1772 | val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0); | |
796b6678 | 1773 | val.mask = ~((HOST_WIDE_INT) MALLOC_ABI_ALIGNMENT |
1774 | / BITS_PER_UNIT - 1); | |
153c3b50 | 1775 | break; |
1776 | ||
1777 | case BUILT_IN_ALLOCA: | |
581bf1c2 | 1778 | case BUILT_IN_ALLOCA_WITH_ALIGN: |
1779 | align = (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_ALLOCA_WITH_ALIGN | |
f9ae6f95 | 1780 | ? TREE_INT_CST_LOW (gimple_call_arg (stmt, 1)) |
581bf1c2 | 1781 | : BIGGEST_ALIGNMENT); |
153c3b50 | 1782 | val.lattice_val = CONSTANT; |
1783 | val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0); | |
796b6678 | 1784 | val.mask = ~((HOST_WIDE_INT) align / BITS_PER_UNIT - 1); |
153c3b50 | 1785 | break; |
1786 | ||
939514e9 | 1787 | /* These builtins return their first argument, unmodified. */ |
1788 | case BUILT_IN_MEMCPY: | |
1789 | case BUILT_IN_MEMMOVE: | |
1790 | case BUILT_IN_MEMSET: | |
1791 | case BUILT_IN_STRCPY: | |
1792 | case BUILT_IN_STRNCPY: | |
1793 | case BUILT_IN_MEMCPY_CHK: | |
1794 | case BUILT_IN_MEMMOVE_CHK: | |
1795 | case BUILT_IN_MEMSET_CHK: | |
1796 | case BUILT_IN_STRCPY_CHK: | |
1797 | case BUILT_IN_STRNCPY_CHK: | |
1798 | val = get_value_for_expr (gimple_call_arg (stmt, 0), true); | |
1799 | break; | |
1800 | ||
fca0886c | 1801 | case BUILT_IN_ASSUME_ALIGNED: |
237e78b1 | 1802 | val = bit_value_assume_aligned (stmt, NULL_TREE, val, false); |
fca0886c | 1803 | break; |
1804 | ||
153c3b50 | 1805 | default:; |
1806 | } | |
1807 | } | |
237e78b1 | 1808 | if (is_gimple_call (stmt) && gimple_call_lhs (stmt)) |
1809 | { | |
1810 | tree fntype = gimple_call_fntype (stmt); | |
1811 | if (fntype) | |
1812 | { | |
1813 | tree attrs = lookup_attribute ("assume_aligned", | |
1814 | TYPE_ATTRIBUTES (fntype)); | |
1815 | if (attrs) | |
1816 | val = bit_value_assume_aligned (stmt, attrs, val, false); | |
1817 | attrs = lookup_attribute ("alloc_align", | |
1818 | TYPE_ATTRIBUTES (fntype)); | |
1819 | if (attrs) | |
1820 | val = bit_value_assume_aligned (stmt, attrs, val, true); | |
1821 | } | |
1822 | } | |
b7e55469 | 1823 | is_constant = (val.lattice_val == CONSTANT); |
912f109f | 1824 | } |
1825 | ||
fc08b993 | 1826 | if (flag_tree_bit_ccp |
1827 | && ((is_constant && TREE_CODE (val.value) == INTEGER_CST) | |
1828 | || (!is_constant && likelyvalue != UNDEFINED)) | |
1829 | && gimple_get_lhs (stmt) | |
1830 | && TREE_CODE (gimple_get_lhs (stmt)) == SSA_NAME) | |
1831 | { | |
1832 | tree lhs = gimple_get_lhs (stmt); | |
9c1be15e | 1833 | wide_int nonzero_bits = get_nonzero_bits (lhs); |
1834 | if (nonzero_bits != -1) | |
fc08b993 | 1835 | { |
1836 | if (!is_constant) | |
1837 | { | |
1838 | val.lattice_val = CONSTANT; | |
1839 | val.value = build_zero_cst (TREE_TYPE (lhs)); | |
9c1be15e | 1840 | val.mask = extend_mask (nonzero_bits); |
fc08b993 | 1841 | is_constant = true; |
1842 | } | |
1843 | else | |
1844 | { | |
9c1be15e | 1845 | if (wi::bit_and_not (val.value, nonzero_bits) != 0) |
aeb682a2 | 1846 | val.value = wide_int_to_tree (TREE_TYPE (lhs), |
9c1be15e | 1847 | nonzero_bits & val.value); |
aeb682a2 | 1848 | if (nonzero_bits == 0) |
1849 | val.mask = 0; | |
fc08b993 | 1850 | else |
9c1be15e | 1851 | val.mask = extend_mask (nonzero_bits); |
fc08b993 | 1852 | } |
1853 | } | |
1854 | } | |
1855 | ||
b7e55469 | 1856 | if (!is_constant) |
4ee9c684 | 1857 | { |
1858 | /* The statement produced a nonconstant value. If the statement | |
88dbf20f | 1859 | had UNDEFINED operands, then the result of the statement |
1860 | should be UNDEFINED. Otherwise, the statement is VARYING. */ | |
bfa30570 | 1861 | if (likelyvalue == UNDEFINED) |
b7e55469 | 1862 | { |
1863 | val.lattice_val = likelyvalue; | |
e913b5cd | 1864 | val.mask = 0; |
b7e55469 | 1865 | } |
b765fa12 | 1866 | else |
b7e55469 | 1867 | { |
1868 | val.lattice_val = VARYING; | |
e913b5cd | 1869 | val.mask = -1; |
b7e55469 | 1870 | } |
b765fa12 | 1871 | |
88dbf20f | 1872 | val.value = NULL_TREE; |
4ee9c684 | 1873 | } |
41511585 | 1874 | |
1875 | return val; | |
4ee9c684 | 1876 | } |
1877 | ||
de6bd75e | 1878 | typedef hash_table <pointer_hash <gimple_statement_base> > gimple_htab; |
2b15d2ba | 1879 | |
582a80ed | 1880 | /* Given a BUILT_IN_STACK_SAVE value SAVED_VAL, insert a clobber of VAR before |
1881 | each matching BUILT_IN_STACK_RESTORE. Mark visited phis in VISITED. */ | |
1882 | ||
1883 | static void | |
2b15d2ba | 1884 | insert_clobber_before_stack_restore (tree saved_val, tree var, |
1885 | gimple_htab *visited) | |
582a80ed | 1886 | { |
1887 | gimple stmt, clobber_stmt; | |
1888 | tree clobber; | |
1889 | imm_use_iterator iter; | |
1890 | gimple_stmt_iterator i; | |
1891 | gimple *slot; | |
1892 | ||
1893 | FOR_EACH_IMM_USE_STMT (stmt, iter, saved_val) | |
1894 | if (gimple_call_builtin_p (stmt, BUILT_IN_STACK_RESTORE)) | |
1895 | { | |
f1f41a6c | 1896 | clobber = build_constructor (TREE_TYPE (var), |
1897 | NULL); | |
582a80ed | 1898 | TREE_THIS_VOLATILE (clobber) = 1; |
1899 | clobber_stmt = gimple_build_assign (var, clobber); | |
1900 | ||
1901 | i = gsi_for_stmt (stmt); | |
1902 | gsi_insert_before (&i, clobber_stmt, GSI_SAME_STMT); | |
1903 | } | |
1904 | else if (gimple_code (stmt) == GIMPLE_PHI) | |
1905 | { | |
2b15d2ba | 1906 | if (!visited->is_created ()) |
1907 | visited->create (10); | |
582a80ed | 1908 | |
2b15d2ba | 1909 | slot = visited->find_slot (stmt, INSERT); |
582a80ed | 1910 | if (*slot != NULL) |
1911 | continue; | |
1912 | ||
1913 | *slot = stmt; | |
1914 | insert_clobber_before_stack_restore (gimple_phi_result (stmt), var, | |
1915 | visited); | |
1916 | } | |
42eed683 | 1917 | else if (gimple_assign_ssa_name_copy_p (stmt)) |
1918 | insert_clobber_before_stack_restore (gimple_assign_lhs (stmt), var, | |
1919 | visited); | |
582a80ed | 1920 | else |
1921 | gcc_assert (is_gimple_debug (stmt)); | |
1922 | } | |
1923 | ||
1924 | /* Advance the iterator to the previous non-debug gimple statement in the same | |
1925 | or dominating basic block. */ | |
1926 | ||
1927 | static inline void | |
1928 | gsi_prev_dom_bb_nondebug (gimple_stmt_iterator *i) | |
1929 | { | |
1930 | basic_block dom; | |
1931 | ||
1932 | gsi_prev_nondebug (i); | |
1933 | while (gsi_end_p (*i)) | |
1934 | { | |
1935 | dom = get_immediate_dominator (CDI_DOMINATORS, i->bb); | |
34154e27 | 1936 | if (dom == NULL || dom == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
582a80ed | 1937 | return; |
1938 | ||
1939 | *i = gsi_last_bb (dom); | |
1940 | } | |
1941 | } | |
1942 | ||
1943 | /* Find a BUILT_IN_STACK_SAVE dominating gsi_stmt (I), and insert | |
1543f720 | 1944 | a clobber of VAR before each matching BUILT_IN_STACK_RESTORE. |
1945 | ||
1946 | It is possible that BUILT_IN_STACK_SAVE cannot be find in a dominator when a | |
1947 | previous pass (such as DOM) duplicated it along multiple paths to a BB. In | |
1948 | that case the function gives up without inserting the clobbers. */ | |
582a80ed | 1949 | |
1950 | static void | |
1951 | insert_clobbers_for_var (gimple_stmt_iterator i, tree var) | |
1952 | { | |
582a80ed | 1953 | gimple stmt; |
1954 | tree saved_val; | |
2b15d2ba | 1955 | gimple_htab visited; |
582a80ed | 1956 | |
1543f720 | 1957 | for (; !gsi_end_p (i); gsi_prev_dom_bb_nondebug (&i)) |
582a80ed | 1958 | { |
1959 | stmt = gsi_stmt (i); | |
1960 | ||
1961 | if (!gimple_call_builtin_p (stmt, BUILT_IN_STACK_SAVE)) | |
1962 | continue; | |
582a80ed | 1963 | |
1964 | saved_val = gimple_call_lhs (stmt); | |
1965 | if (saved_val == NULL_TREE) | |
1966 | continue; | |
1967 | ||
1968 | insert_clobber_before_stack_restore (saved_val, var, &visited); | |
1969 | break; | |
1970 | } | |
1971 | ||
2b15d2ba | 1972 | if (visited.is_created ()) |
1973 | visited.dispose (); | |
582a80ed | 1974 | } |
1975 | ||
581bf1c2 | 1976 | /* Detects a __builtin_alloca_with_align with constant size argument. Declares |
1977 | fixed-size array and returns the address, if found, otherwise returns | |
1978 | NULL_TREE. */ | |
9a65cc0a | 1979 | |
1980 | static tree | |
581bf1c2 | 1981 | fold_builtin_alloca_with_align (gimple stmt) |
9a65cc0a | 1982 | { |
1983 | unsigned HOST_WIDE_INT size, threshold, n_elem; | |
1984 | tree lhs, arg, block, var, elem_type, array_type; | |
9a65cc0a | 1985 | |
1986 | /* Get lhs. */ | |
1987 | lhs = gimple_call_lhs (stmt); | |
1988 | if (lhs == NULL_TREE) | |
1989 | return NULL_TREE; | |
1990 | ||
1991 | /* Detect constant argument. */ | |
1992 | arg = get_constant_value (gimple_call_arg (stmt, 0)); | |
6e93d308 | 1993 | if (arg == NULL_TREE |
1994 | || TREE_CODE (arg) != INTEGER_CST | |
e913b5cd | 1995 | || !tree_fits_uhwi_p (arg)) |
9a65cc0a | 1996 | return NULL_TREE; |
6e93d308 | 1997 | |
8c53c46c | 1998 | size = tree_to_uhwi (arg); |
9a65cc0a | 1999 | |
581bf1c2 | 2000 | /* Heuristic: don't fold large allocas. */ |
9a65cc0a | 2001 | threshold = (unsigned HOST_WIDE_INT)PARAM_VALUE (PARAM_LARGE_STACK_FRAME); |
581bf1c2 | 2002 | /* In case the alloca is located at function entry, it has the same lifetime |
2003 | as a declared array, so we allow a larger size. */ | |
9a65cc0a | 2004 | block = gimple_block (stmt); |
2005 | if (!(cfun->after_inlining | |
2006 | && TREE_CODE (BLOCK_SUPERCONTEXT (block)) == FUNCTION_DECL)) | |
2007 | threshold /= 10; | |
2008 | if (size > threshold) | |
2009 | return NULL_TREE; | |
2010 | ||
2011 | /* Declare array. */ | |
2012 | elem_type = build_nonstandard_integer_type (BITS_PER_UNIT, 1); | |
2013 | n_elem = size * 8 / BITS_PER_UNIT; | |
9a65cc0a | 2014 | array_type = build_array_type_nelts (elem_type, n_elem); |
2015 | var = create_tmp_var (array_type, NULL); | |
f9ae6f95 | 2016 | DECL_ALIGN (var) = TREE_INT_CST_LOW (gimple_call_arg (stmt, 1)); |
3d4a0a4b | 2017 | { |
2018 | struct ptr_info_def *pi = SSA_NAME_PTR_INFO (lhs); | |
2019 | if (pi != NULL && !pi->pt.anything) | |
2020 | { | |
2021 | bool singleton_p; | |
2022 | unsigned uid; | |
2023 | singleton_p = pt_solution_singleton_p (&pi->pt, &uid); | |
2024 | gcc_assert (singleton_p); | |
2025 | SET_DECL_PT_UID (var, uid); | |
2026 | } | |
2027 | } | |
9a65cc0a | 2028 | |
2029 | /* Fold alloca to the address of the array. */ | |
2030 | return fold_convert (TREE_TYPE (lhs), build_fold_addr_expr (var)); | |
2031 | } | |
2032 | ||
6688f8ec | 2033 | /* Fold the stmt at *GSI with CCP specific information that propagating |
2034 | and regular folding does not catch. */ | |
2035 | ||
2036 | static bool | |
2037 | ccp_fold_stmt (gimple_stmt_iterator *gsi) | |
2038 | { | |
2039 | gimple stmt = gsi_stmt (*gsi); | |
6688f8ec | 2040 | |
94144e68 | 2041 | switch (gimple_code (stmt)) |
2042 | { | |
2043 | case GIMPLE_COND: | |
2044 | { | |
2045 | prop_value_t val; | |
2046 | /* Statement evaluation will handle type mismatches in constants | |
2047 | more gracefully than the final propagation. This allows us to | |
2048 | fold more conditionals here. */ | |
2049 | val = evaluate_stmt (stmt); | |
2050 | if (val.lattice_val != CONSTANT | |
796b6678 | 2051 | || val.mask != 0) |
94144e68 | 2052 | return false; |
2053 | ||
b7e55469 | 2054 | if (dump_file) |
2055 | { | |
2056 | fprintf (dump_file, "Folding predicate "); | |
2057 | print_gimple_expr (dump_file, stmt, 0, 0); | |
2058 | fprintf (dump_file, " to "); | |
2059 | print_generic_expr (dump_file, val.value, 0); | |
2060 | fprintf (dump_file, "\n"); | |
2061 | } | |
2062 | ||
94144e68 | 2063 | if (integer_zerop (val.value)) |
2064 | gimple_cond_make_false (stmt); | |
2065 | else | |
2066 | gimple_cond_make_true (stmt); | |
6688f8ec | 2067 | |
94144e68 | 2068 | return true; |
2069 | } | |
6688f8ec | 2070 | |
94144e68 | 2071 | case GIMPLE_CALL: |
2072 | { | |
2073 | tree lhs = gimple_call_lhs (stmt); | |
3064bb7b | 2074 | int flags = gimple_call_flags (stmt); |
15d138c9 | 2075 | tree val; |
94144e68 | 2076 | tree argt; |
2077 | bool changed = false; | |
2078 | unsigned i; | |
2079 | ||
2080 | /* If the call was folded into a constant make sure it goes | |
2081 | away even if we cannot propagate into all uses because of | |
2082 | type issues. */ | |
2083 | if (lhs | |
2084 | && TREE_CODE (lhs) == SSA_NAME | |
3064bb7b | 2085 | && (val = get_constant_value (lhs)) |
2086 | /* Don't optimize away calls that have side-effects. */ | |
2087 | && (flags & (ECF_CONST|ECF_PURE)) != 0 | |
2088 | && (flags & ECF_LOOPING_CONST_OR_PURE) == 0) | |
94144e68 | 2089 | { |
15d138c9 | 2090 | tree new_rhs = unshare_expr (val); |
338cce8f | 2091 | bool res; |
94144e68 | 2092 | if (!useless_type_conversion_p (TREE_TYPE (lhs), |
2093 | TREE_TYPE (new_rhs))) | |
2094 | new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs); | |
338cce8f | 2095 | res = update_call_from_tree (gsi, new_rhs); |
2096 | gcc_assert (res); | |
94144e68 | 2097 | return true; |
2098 | } | |
2099 | ||
fb049fba | 2100 | /* Internal calls provide no argument types, so the extra laxity |
2101 | for normal calls does not apply. */ | |
2102 | if (gimple_call_internal_p (stmt)) | |
2103 | return false; | |
2104 | ||
581bf1c2 | 2105 | /* The heuristic of fold_builtin_alloca_with_align differs before and |
2106 | after inlining, so we don't require the arg to be changed into a | |
2107 | constant for folding, but just to be constant. */ | |
2108 | if (gimple_call_builtin_p (stmt, BUILT_IN_ALLOCA_WITH_ALIGN)) | |
9a65cc0a | 2109 | { |
581bf1c2 | 2110 | tree new_rhs = fold_builtin_alloca_with_align (stmt); |
6e93d308 | 2111 | if (new_rhs) |
2112 | { | |
2113 | bool res = update_call_from_tree (gsi, new_rhs); | |
582a80ed | 2114 | tree var = TREE_OPERAND (TREE_OPERAND (new_rhs, 0),0); |
6e93d308 | 2115 | gcc_assert (res); |
582a80ed | 2116 | insert_clobbers_for_var (*gsi, var); |
6e93d308 | 2117 | return true; |
2118 | } | |
9a65cc0a | 2119 | } |
2120 | ||
94144e68 | 2121 | /* Propagate into the call arguments. Compared to replace_uses_in |
2122 | this can use the argument slot types for type verification | |
2123 | instead of the current argument type. We also can safely | |
2124 | drop qualifiers here as we are dealing with constants anyway. */ | |
2de00a2d | 2125 | argt = TYPE_ARG_TYPES (gimple_call_fntype (stmt)); |
94144e68 | 2126 | for (i = 0; i < gimple_call_num_args (stmt) && argt; |
2127 | ++i, argt = TREE_CHAIN (argt)) | |
2128 | { | |
2129 | tree arg = gimple_call_arg (stmt, i); | |
2130 | if (TREE_CODE (arg) == SSA_NAME | |
15d138c9 | 2131 | && (val = get_constant_value (arg)) |
94144e68 | 2132 | && useless_type_conversion_p |
2133 | (TYPE_MAIN_VARIANT (TREE_VALUE (argt)), | |
15d138c9 | 2134 | TYPE_MAIN_VARIANT (TREE_TYPE (val)))) |
94144e68 | 2135 | { |
15d138c9 | 2136 | gimple_call_set_arg (stmt, i, unshare_expr (val)); |
94144e68 | 2137 | changed = true; |
2138 | } | |
2139 | } | |
e16f4c39 | 2140 | |
94144e68 | 2141 | return changed; |
2142 | } | |
6688f8ec | 2143 | |
6872bf3c | 2144 | case GIMPLE_ASSIGN: |
2145 | { | |
2146 | tree lhs = gimple_assign_lhs (stmt); | |
15d138c9 | 2147 | tree val; |
6872bf3c | 2148 | |
2149 | /* If we have a load that turned out to be constant replace it | |
2150 | as we cannot propagate into all uses in all cases. */ | |
2151 | if (gimple_assign_single_p (stmt) | |
2152 | && TREE_CODE (lhs) == SSA_NAME | |
15d138c9 | 2153 | && (val = get_constant_value (lhs))) |
6872bf3c | 2154 | { |
15d138c9 | 2155 | tree rhs = unshare_expr (val); |
6872bf3c | 2156 | if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs))) |
182cf5a9 | 2157 | rhs = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), rhs); |
6872bf3c | 2158 | gimple_assign_set_rhs_from_tree (gsi, rhs); |
2159 | return true; | |
2160 | } | |
2161 | ||
2162 | return false; | |
2163 | } | |
2164 | ||
94144e68 | 2165 | default: |
2166 | return false; | |
2167 | } | |
6688f8ec | 2168 | } |
2169 | ||
41511585 | 2170 | /* Visit the assignment statement STMT. Set the value of its LHS to the |
88dbf20f | 2171 | value computed by the RHS and store LHS in *OUTPUT_P. If STMT |
2172 | creates virtual definitions, set the value of each new name to that | |
75a70cf9 | 2173 | of the RHS (if we can derive a constant out of the RHS). |
2174 | Value-returning call statements also perform an assignment, and | |
2175 | are handled here. */ | |
4ee9c684 | 2176 | |
41511585 | 2177 | static enum ssa_prop_result |
75a70cf9 | 2178 | visit_assignment (gimple stmt, tree *output_p) |
4ee9c684 | 2179 | { |
88dbf20f | 2180 | prop_value_t val; |
88dbf20f | 2181 | enum ssa_prop_result retval; |
4ee9c684 | 2182 | |
75a70cf9 | 2183 | tree lhs = gimple_get_lhs (stmt); |
4ee9c684 | 2184 | |
75a70cf9 | 2185 | gcc_assert (gimple_code (stmt) != GIMPLE_CALL |
2186 | || gimple_call_lhs (stmt) != NULL_TREE); | |
2187 | ||
15d138c9 | 2188 | if (gimple_assign_single_p (stmt) |
2189 | && gimple_assign_rhs_code (stmt) == SSA_NAME) | |
2190 | /* For a simple copy operation, we copy the lattice values. */ | |
2191 | val = *get_value (gimple_assign_rhs1 (stmt)); | |
41511585 | 2192 | else |
75a70cf9 | 2193 | /* Evaluate the statement, which could be |
2194 | either a GIMPLE_ASSIGN or a GIMPLE_CALL. */ | |
04236c3a | 2195 | val = evaluate_stmt (stmt); |
4ee9c684 | 2196 | |
88dbf20f | 2197 | retval = SSA_PROP_NOT_INTERESTING; |
4ee9c684 | 2198 | |
41511585 | 2199 | /* Set the lattice value of the statement's output. */ |
88dbf20f | 2200 | if (TREE_CODE (lhs) == SSA_NAME) |
4ee9c684 | 2201 | { |
88dbf20f | 2202 | /* If STMT is an assignment to an SSA_NAME, we only have one |
2203 | value to set. */ | |
2204 | if (set_lattice_value (lhs, val)) | |
2205 | { | |
2206 | *output_p = lhs; | |
2207 | if (val.lattice_val == VARYING) | |
2208 | retval = SSA_PROP_VARYING; | |
2209 | else | |
2210 | retval = SSA_PROP_INTERESTING; | |
2211 | } | |
4ee9c684 | 2212 | } |
88dbf20f | 2213 | |
2214 | return retval; | |
4ee9c684 | 2215 | } |
2216 | ||
4ee9c684 | 2217 | |
41511585 | 2218 | /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING |
2219 | if it can determine which edge will be taken. Otherwise, return | |
2220 | SSA_PROP_VARYING. */ | |
2221 | ||
2222 | static enum ssa_prop_result | |
75a70cf9 | 2223 | visit_cond_stmt (gimple stmt, edge *taken_edge_p) |
4ee9c684 | 2224 | { |
88dbf20f | 2225 | prop_value_t val; |
41511585 | 2226 | basic_block block; |
2227 | ||
75a70cf9 | 2228 | block = gimple_bb (stmt); |
41511585 | 2229 | val = evaluate_stmt (stmt); |
b7e55469 | 2230 | if (val.lattice_val != CONSTANT |
796b6678 | 2231 | || val.mask != 0) |
b7e55469 | 2232 | return SSA_PROP_VARYING; |
41511585 | 2233 | |
2234 | /* Find which edge out of the conditional block will be taken and add it | |
2235 | to the worklist. If no single edge can be determined statically, | |
2236 | return SSA_PROP_VARYING to feed all the outgoing edges to the | |
2237 | propagation engine. */ | |
b7e55469 | 2238 | *taken_edge_p = find_taken_edge (block, val.value); |
41511585 | 2239 | if (*taken_edge_p) |
2240 | return SSA_PROP_INTERESTING; | |
2241 | else | |
2242 | return SSA_PROP_VARYING; | |
4ee9c684 | 2243 | } |
2244 | ||
4ee9c684 | 2245 | |
41511585 | 2246 | /* Evaluate statement STMT. If the statement produces an output value and |
2247 | its evaluation changes the lattice value of its output, return | |
2248 | SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the | |
2249 | output value. | |
48e1416a | 2250 | |
41511585 | 2251 | If STMT is a conditional branch and we can determine its truth |
2252 | value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying | |
2253 | value, return SSA_PROP_VARYING. */ | |
4ee9c684 | 2254 | |
41511585 | 2255 | static enum ssa_prop_result |
75a70cf9 | 2256 | ccp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p) |
41511585 | 2257 | { |
41511585 | 2258 | tree def; |
2259 | ssa_op_iter iter; | |
4ee9c684 | 2260 | |
41511585 | 2261 | if (dump_file && (dump_flags & TDF_DETAILS)) |
4ee9c684 | 2262 | { |
88dbf20f | 2263 | fprintf (dump_file, "\nVisiting statement:\n"); |
75a70cf9 | 2264 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
4ee9c684 | 2265 | } |
4ee9c684 | 2266 | |
75a70cf9 | 2267 | switch (gimple_code (stmt)) |
4ee9c684 | 2268 | { |
75a70cf9 | 2269 | case GIMPLE_ASSIGN: |
2270 | /* If the statement is an assignment that produces a single | |
2271 | output value, evaluate its RHS to see if the lattice value of | |
2272 | its output has changed. */ | |
2273 | return visit_assignment (stmt, output_p); | |
2274 | ||
2275 | case GIMPLE_CALL: | |
2276 | /* A value-returning call also performs an assignment. */ | |
2277 | if (gimple_call_lhs (stmt) != NULL_TREE) | |
2278 | return visit_assignment (stmt, output_p); | |
2279 | break; | |
2280 | ||
2281 | case GIMPLE_COND: | |
2282 | case GIMPLE_SWITCH: | |
2283 | /* If STMT is a conditional branch, see if we can determine | |
2284 | which branch will be taken. */ | |
2285 | /* FIXME. It appears that we should be able to optimize | |
2286 | computed GOTOs here as well. */ | |
2287 | return visit_cond_stmt (stmt, taken_edge_p); | |
2288 | ||
2289 | default: | |
2290 | break; | |
4ee9c684 | 2291 | } |
4ee9c684 | 2292 | |
41511585 | 2293 | /* Any other kind of statement is not interesting for constant |
2294 | propagation and, therefore, not worth simulating. */ | |
41511585 | 2295 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2296 | fprintf (dump_file, "No interesting values produced. Marked VARYING.\n"); | |
4ee9c684 | 2297 | |
41511585 | 2298 | /* Definitions made by statements other than assignments to |
2299 | SSA_NAMEs represent unknown modifications to their outputs. | |
2300 | Mark them VARYING. */ | |
88dbf20f | 2301 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) |
2302 | { | |
e913b5cd | 2303 | prop_value_t v = { VARYING, NULL_TREE, -1 }; |
88dbf20f | 2304 | set_lattice_value (def, v); |
2305 | } | |
4ee9c684 | 2306 | |
41511585 | 2307 | return SSA_PROP_VARYING; |
2308 | } | |
4ee9c684 | 2309 | |
4ee9c684 | 2310 | |
88dbf20f | 2311 | /* Main entry point for SSA Conditional Constant Propagation. */ |
41511585 | 2312 | |
33a34f1e | 2313 | static unsigned int |
61207d43 | 2314 | do_ssa_ccp (void) |
41511585 | 2315 | { |
582a80ed | 2316 | unsigned int todo = 0; |
2317 | calculate_dominance_info (CDI_DOMINATORS); | |
41511585 | 2318 | ccp_initialize (); |
2319 | ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node); | |
33a34f1e | 2320 | if (ccp_finalize ()) |
560965e9 | 2321 | todo = (TODO_cleanup_cfg | TODO_update_ssa); |
582a80ed | 2322 | free_dominance_info (CDI_DOMINATORS); |
2323 | return todo; | |
4ee9c684 | 2324 | } |
2325 | ||
5664499b | 2326 | |
cbe8bda8 | 2327 | namespace { |
2328 | ||
2329 | const pass_data pass_data_ccp = | |
41511585 | 2330 | { |
cbe8bda8 | 2331 | GIMPLE_PASS, /* type */ |
2332 | "ccp", /* name */ | |
2333 | OPTGROUP_NONE, /* optinfo_flags */ | |
cbe8bda8 | 2334 | true, /* has_execute */ |
2335 | TV_TREE_CCP, /* tv_id */ | |
2336 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
2337 | 0, /* properties_provided */ | |
2338 | 0, /* properties_destroyed */ | |
2339 | 0, /* todo_flags_start */ | |
2340 | ( TODO_verify_ssa | TODO_update_address_taken | |
2341 | | TODO_verify_stmts ), /* todo_flags_finish */ | |
41511585 | 2342 | }; |
4ee9c684 | 2343 | |
cbe8bda8 | 2344 | class pass_ccp : public gimple_opt_pass |
2345 | { | |
2346 | public: | |
9af5ce0c | 2347 | pass_ccp (gcc::context *ctxt) |
2348 | : gimple_opt_pass (pass_data_ccp, ctxt) | |
cbe8bda8 | 2349 | {} |
2350 | ||
2351 | /* opt_pass methods: */ | |
ae84f584 | 2352 | opt_pass * clone () { return new pass_ccp (m_ctxt); } |
31315c24 | 2353 | virtual bool gate (function *) { return flag_tree_ccp != 0; } |
65b0537f | 2354 | virtual unsigned int execute (function *) { return do_ssa_ccp (); } |
cbe8bda8 | 2355 | |
2356 | }; // class pass_ccp | |
2357 | ||
2358 | } // anon namespace | |
2359 | ||
2360 | gimple_opt_pass * | |
2361 | make_pass_ccp (gcc::context *ctxt) | |
2362 | { | |
2363 | return new pass_ccp (ctxt); | |
2364 | } | |
2365 | ||
4ee9c684 | 2366 | |
75a70cf9 | 2367 | |
bdd0e199 | 2368 | /* Try to optimize out __builtin_stack_restore. Optimize it out |
2369 | if there is another __builtin_stack_restore in the same basic | |
2370 | block and no calls or ASM_EXPRs are in between, or if this block's | |
2371 | only outgoing edge is to EXIT_BLOCK and there are no calls or | |
2372 | ASM_EXPRs after this __builtin_stack_restore. */ | |
2373 | ||
2374 | static tree | |
75a70cf9 | 2375 | optimize_stack_restore (gimple_stmt_iterator i) |
bdd0e199 | 2376 | { |
6ea999da | 2377 | tree callee; |
2378 | gimple stmt; | |
75a70cf9 | 2379 | |
2380 | basic_block bb = gsi_bb (i); | |
2381 | gimple call = gsi_stmt (i); | |
bdd0e199 | 2382 | |
75a70cf9 | 2383 | if (gimple_code (call) != GIMPLE_CALL |
2384 | || gimple_call_num_args (call) != 1 | |
2385 | || TREE_CODE (gimple_call_arg (call, 0)) != SSA_NAME | |
2386 | || !POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call, 0)))) | |
bdd0e199 | 2387 | return NULL_TREE; |
2388 | ||
75a70cf9 | 2389 | for (gsi_next (&i); !gsi_end_p (i); gsi_next (&i)) |
bdd0e199 | 2390 | { |
75a70cf9 | 2391 | stmt = gsi_stmt (i); |
2392 | if (gimple_code (stmt) == GIMPLE_ASM) | |
bdd0e199 | 2393 | return NULL_TREE; |
75a70cf9 | 2394 | if (gimple_code (stmt) != GIMPLE_CALL) |
bdd0e199 | 2395 | continue; |
2396 | ||
75a70cf9 | 2397 | callee = gimple_call_fndecl (stmt); |
c40a6f90 | 2398 | if (!callee |
2399 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL | |
2400 | /* All regular builtins are ok, just obviously not alloca. */ | |
581bf1c2 | 2401 | || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA |
2402 | || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA_WITH_ALIGN) | |
bdd0e199 | 2403 | return NULL_TREE; |
2404 | ||
2405 | if (DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_RESTORE) | |
6ea999da | 2406 | goto second_stack_restore; |
bdd0e199 | 2407 | } |
2408 | ||
6ea999da | 2409 | if (!gsi_end_p (i)) |
bdd0e199 | 2410 | return NULL_TREE; |
2411 | ||
6ea999da | 2412 | /* Allow one successor of the exit block, or zero successors. */ |
2413 | switch (EDGE_COUNT (bb->succs)) | |
2414 | { | |
2415 | case 0: | |
2416 | break; | |
2417 | case 1: | |
34154e27 | 2418 | if (single_succ_edge (bb)->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
6ea999da | 2419 | return NULL_TREE; |
2420 | break; | |
2421 | default: | |
2422 | return NULL_TREE; | |
2423 | } | |
2424 | second_stack_restore: | |
bdd0e199 | 2425 | |
6ea999da | 2426 | /* If there's exactly one use, then zap the call to __builtin_stack_save. |
2427 | If there are multiple uses, then the last one should remove the call. | |
2428 | In any case, whether the call to __builtin_stack_save can be removed | |
2429 | or not is irrelevant to removing the call to __builtin_stack_restore. */ | |
2430 | if (has_single_use (gimple_call_arg (call, 0))) | |
2431 | { | |
2432 | gimple stack_save = SSA_NAME_DEF_STMT (gimple_call_arg (call, 0)); | |
2433 | if (is_gimple_call (stack_save)) | |
2434 | { | |
2435 | callee = gimple_call_fndecl (stack_save); | |
2436 | if (callee | |
2437 | && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL | |
2438 | && DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_SAVE) | |
2439 | { | |
2440 | gimple_stmt_iterator stack_save_gsi; | |
2441 | tree rhs; | |
bdd0e199 | 2442 | |
6ea999da | 2443 | stack_save_gsi = gsi_for_stmt (stack_save); |
2444 | rhs = build_int_cst (TREE_TYPE (gimple_call_arg (call, 0)), 0); | |
2445 | update_call_from_tree (&stack_save_gsi, rhs); | |
2446 | } | |
2447 | } | |
2448 | } | |
bdd0e199 | 2449 | |
75a70cf9 | 2450 | /* No effect, so the statement will be deleted. */ |
bdd0e199 | 2451 | return integer_zero_node; |
2452 | } | |
75a70cf9 | 2453 | |
8a58ed0a | 2454 | /* If va_list type is a simple pointer and nothing special is needed, |
2455 | optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0), | |
2456 | __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple | |
2457 | pointer assignment. */ | |
2458 | ||
2459 | static tree | |
75a70cf9 | 2460 | optimize_stdarg_builtin (gimple call) |
8a58ed0a | 2461 | { |
5f57a8b1 | 2462 | tree callee, lhs, rhs, cfun_va_list; |
8a58ed0a | 2463 | bool va_list_simple_ptr; |
389dd41b | 2464 | location_t loc = gimple_location (call); |
8a58ed0a | 2465 | |
75a70cf9 | 2466 | if (gimple_code (call) != GIMPLE_CALL) |
8a58ed0a | 2467 | return NULL_TREE; |
2468 | ||
75a70cf9 | 2469 | callee = gimple_call_fndecl (call); |
5f57a8b1 | 2470 | |
2471 | cfun_va_list = targetm.fn_abi_va_list (callee); | |
2472 | va_list_simple_ptr = POINTER_TYPE_P (cfun_va_list) | |
2473 | && (TREE_TYPE (cfun_va_list) == void_type_node | |
2474 | || TREE_TYPE (cfun_va_list) == char_type_node); | |
2475 | ||
8a58ed0a | 2476 | switch (DECL_FUNCTION_CODE (callee)) |
2477 | { | |
2478 | case BUILT_IN_VA_START: | |
2479 | if (!va_list_simple_ptr | |
2480 | || targetm.expand_builtin_va_start != NULL | |
e7ed5dd7 | 2481 | || !builtin_decl_explicit_p (BUILT_IN_NEXT_ARG)) |
8a58ed0a | 2482 | return NULL_TREE; |
2483 | ||
75a70cf9 | 2484 | if (gimple_call_num_args (call) != 2) |
8a58ed0a | 2485 | return NULL_TREE; |
2486 | ||
75a70cf9 | 2487 | lhs = gimple_call_arg (call, 0); |
8a58ed0a | 2488 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) |
2489 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
5f57a8b1 | 2490 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
8a58ed0a | 2491 | return NULL_TREE; |
48e1416a | 2492 | |
389dd41b | 2493 | lhs = build_fold_indirect_ref_loc (loc, lhs); |
b9a16870 | 2494 | rhs = build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_NEXT_ARG), |
75a70cf9 | 2495 | 1, integer_zero_node); |
389dd41b | 2496 | rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); |
8a58ed0a | 2497 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); |
2498 | ||
2499 | case BUILT_IN_VA_COPY: | |
2500 | if (!va_list_simple_ptr) | |
2501 | return NULL_TREE; | |
2502 | ||
75a70cf9 | 2503 | if (gimple_call_num_args (call) != 2) |
8a58ed0a | 2504 | return NULL_TREE; |
2505 | ||
75a70cf9 | 2506 | lhs = gimple_call_arg (call, 0); |
8a58ed0a | 2507 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) |
2508 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
5f57a8b1 | 2509 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
8a58ed0a | 2510 | return NULL_TREE; |
2511 | ||
389dd41b | 2512 | lhs = build_fold_indirect_ref_loc (loc, lhs); |
75a70cf9 | 2513 | rhs = gimple_call_arg (call, 1); |
8a58ed0a | 2514 | if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs)) |
5f57a8b1 | 2515 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
8a58ed0a | 2516 | return NULL_TREE; |
2517 | ||
389dd41b | 2518 | rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); |
8a58ed0a | 2519 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); |
2520 | ||
2521 | case BUILT_IN_VA_END: | |
75a70cf9 | 2522 | /* No effect, so the statement will be deleted. */ |
8a58ed0a | 2523 | return integer_zero_node; |
2524 | ||
2525 | default: | |
2526 | gcc_unreachable (); | |
2527 | } | |
2528 | } | |
75a70cf9 | 2529 | |
f87df69a | 2530 | /* Attemp to make the block of __builtin_unreachable I unreachable by changing |
2531 | the incoming jumps. Return true if at least one jump was changed. */ | |
2532 | ||
2533 | static bool | |
2534 | optimize_unreachable (gimple_stmt_iterator i) | |
2535 | { | |
2536 | basic_block bb = gsi_bb (i); | |
2537 | gimple_stmt_iterator gsi; | |
2538 | gimple stmt; | |
2539 | edge_iterator ei; | |
2540 | edge e; | |
2541 | bool ret; | |
2542 | ||
2543 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
2544 | { | |
2545 | stmt = gsi_stmt (gsi); | |
2546 | ||
2547 | if (is_gimple_debug (stmt)) | |
2548 | continue; | |
2549 | ||
2550 | if (gimple_code (stmt) == GIMPLE_LABEL) | |
2551 | { | |
2552 | /* Verify we do not need to preserve the label. */ | |
2553 | if (FORCED_LABEL (gimple_label_label (stmt))) | |
2554 | return false; | |
2555 | ||
2556 | continue; | |
2557 | } | |
2558 | ||
2559 | /* Only handle the case that __builtin_unreachable is the first statement | |
2560 | in the block. We rely on DCE to remove stmts without side-effects | |
2561 | before __builtin_unreachable. */ | |
2562 | if (gsi_stmt (gsi) != gsi_stmt (i)) | |
2563 | return false; | |
2564 | } | |
2565 | ||
2566 | ret = false; | |
2567 | FOR_EACH_EDGE (e, ei, bb->preds) | |
2568 | { | |
2569 | gsi = gsi_last_bb (e->src); | |
522f73a1 | 2570 | if (gsi_end_p (gsi)) |
2571 | continue; | |
f87df69a | 2572 | |
522f73a1 | 2573 | stmt = gsi_stmt (gsi); |
2574 | if (gimple_code (stmt) == GIMPLE_COND) | |
f87df69a | 2575 | { |
2576 | if (e->flags & EDGE_TRUE_VALUE) | |
2577 | gimple_cond_make_false (stmt); | |
2578 | else if (e->flags & EDGE_FALSE_VALUE) | |
2579 | gimple_cond_make_true (stmt); | |
2580 | else | |
2581 | gcc_unreachable (); | |
a03a52b4 | 2582 | update_stmt (stmt); |
f87df69a | 2583 | } |
2584 | else | |
2585 | { | |
2586 | /* Todo: handle other cases, f.i. switch statement. */ | |
2587 | continue; | |
2588 | } | |
2589 | ||
2590 | ret = true; | |
2591 | } | |
2592 | ||
2593 | return ret; | |
2594 | } | |
2595 | ||
4ee9c684 | 2596 | /* A simple pass that attempts to fold all builtin functions. This pass |
2597 | is run after we've propagated as many constants as we can. */ | |
2598 | ||
65b0537f | 2599 | namespace { |
2600 | ||
2601 | const pass_data pass_data_fold_builtins = | |
2602 | { | |
2603 | GIMPLE_PASS, /* type */ | |
2604 | "fab", /* name */ | |
2605 | OPTGROUP_NONE, /* optinfo_flags */ | |
2606 | true, /* has_execute */ | |
2607 | TV_NONE, /* tv_id */ | |
2608 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
2609 | 0, /* properties_provided */ | |
2610 | 0, /* properties_destroyed */ | |
2611 | 0, /* todo_flags_start */ | |
2612 | ( TODO_verify_ssa | TODO_update_ssa ), /* todo_flags_finish */ | |
2613 | }; | |
2614 | ||
2615 | class pass_fold_builtins : public gimple_opt_pass | |
2616 | { | |
2617 | public: | |
2618 | pass_fold_builtins (gcc::context *ctxt) | |
2619 | : gimple_opt_pass (pass_data_fold_builtins, ctxt) | |
2620 | {} | |
2621 | ||
2622 | /* opt_pass methods: */ | |
2623 | opt_pass * clone () { return new pass_fold_builtins (m_ctxt); } | |
2624 | virtual unsigned int execute (function *); | |
2625 | ||
2626 | }; // class pass_fold_builtins | |
2627 | ||
2628 | unsigned int | |
2629 | pass_fold_builtins::execute (function *fun) | |
4ee9c684 | 2630 | { |
b36237eb | 2631 | bool cfg_changed = false; |
4ee9c684 | 2632 | basic_block bb; |
b1b7c0c4 | 2633 | unsigned int todoflags = 0; |
48e1416a | 2634 | |
65b0537f | 2635 | FOR_EACH_BB_FN (bb, fun) |
4ee9c684 | 2636 | { |
75a70cf9 | 2637 | gimple_stmt_iterator i; |
2638 | for (i = gsi_start_bb (bb); !gsi_end_p (i); ) | |
4ee9c684 | 2639 | { |
75a70cf9 | 2640 | gimple stmt, old_stmt; |
4ee9c684 | 2641 | tree callee, result; |
0a39fd54 | 2642 | enum built_in_function fcode; |
4ee9c684 | 2643 | |
75a70cf9 | 2644 | stmt = gsi_stmt (i); |
2645 | ||
2646 | if (gimple_code (stmt) != GIMPLE_CALL) | |
0a39fd54 | 2647 | { |
896a0c42 | 2648 | /* Remove all *ssaname_N ={v} {CLOBBER}; stmts, |
2649 | after the last GIMPLE DSE they aren't needed and might | |
2650 | unnecessarily keep the SSA_NAMEs live. */ | |
2651 | if (gimple_clobber_p (stmt)) | |
2652 | { | |
2653 | tree lhs = gimple_assign_lhs (stmt); | |
2654 | if (TREE_CODE (lhs) == MEM_REF | |
2655 | && TREE_CODE (TREE_OPERAND (lhs, 0)) == SSA_NAME) | |
2656 | { | |
2657 | unlink_stmt_vdef (stmt); | |
2658 | gsi_remove (&i, true); | |
2659 | release_defs (stmt); | |
2660 | continue; | |
2661 | } | |
2662 | } | |
75a70cf9 | 2663 | gsi_next (&i); |
0a39fd54 | 2664 | continue; |
2665 | } | |
75a70cf9 | 2666 | callee = gimple_call_fndecl (stmt); |
4ee9c684 | 2667 | if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) |
0a39fd54 | 2668 | { |
75a70cf9 | 2669 | gsi_next (&i); |
0a39fd54 | 2670 | continue; |
2671 | } | |
2672 | fcode = DECL_FUNCTION_CODE (callee); | |
4ee9c684 | 2673 | |
2d18b16d | 2674 | result = gimple_fold_builtin (stmt); |
5a4b7e1e | 2675 | |
2676 | if (result) | |
65b0537f | 2677 | gimple_remove_stmt_histograms (fun, stmt); |
5a4b7e1e | 2678 | |
4ee9c684 | 2679 | if (!result) |
2680 | switch (DECL_FUNCTION_CODE (callee)) | |
2681 | { | |
2682 | case BUILT_IN_CONSTANT_P: | |
2683 | /* Resolve __builtin_constant_p. If it hasn't been | |
2684 | folded to integer_one_node by now, it's fairly | |
2685 | certain that the value simply isn't constant. */ | |
75a70cf9 | 2686 | result = integer_zero_node; |
4ee9c684 | 2687 | break; |
2688 | ||
fca0886c | 2689 | case BUILT_IN_ASSUME_ALIGNED: |
2690 | /* Remove __builtin_assume_aligned. */ | |
2691 | result = gimple_call_arg (stmt, 0); | |
2692 | break; | |
2693 | ||
bdd0e199 | 2694 | case BUILT_IN_STACK_RESTORE: |
75a70cf9 | 2695 | result = optimize_stack_restore (i); |
8a58ed0a | 2696 | if (result) |
2697 | break; | |
75a70cf9 | 2698 | gsi_next (&i); |
8a58ed0a | 2699 | continue; |
2700 | ||
f87df69a | 2701 | case BUILT_IN_UNREACHABLE: |
2702 | if (optimize_unreachable (i)) | |
2703 | cfg_changed = true; | |
2704 | break; | |
2705 | ||
8a58ed0a | 2706 | case BUILT_IN_VA_START: |
2707 | case BUILT_IN_VA_END: | |
2708 | case BUILT_IN_VA_COPY: | |
2709 | /* These shouldn't be folded before pass_stdarg. */ | |
75a70cf9 | 2710 | result = optimize_stdarg_builtin (stmt); |
bdd0e199 | 2711 | if (result) |
2712 | break; | |
2713 | /* FALLTHRU */ | |
2714 | ||
4ee9c684 | 2715 | default: |
75a70cf9 | 2716 | gsi_next (&i); |
4ee9c684 | 2717 | continue; |
2718 | } | |
2719 | ||
f87df69a | 2720 | if (result == NULL_TREE) |
2721 | break; | |
2722 | ||
4ee9c684 | 2723 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2724 | { | |
2725 | fprintf (dump_file, "Simplified\n "); | |
75a70cf9 | 2726 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
4ee9c684 | 2727 | } |
2728 | ||
75a70cf9 | 2729 | old_stmt = stmt; |
75a70cf9 | 2730 | if (!update_call_from_tree (&i, result)) |
0fefde02 | 2731 | { |
2732 | gimplify_and_update_call_from_tree (&i, result); | |
2733 | todoflags |= TODO_update_address_taken; | |
2734 | } | |
de6ed584 | 2735 | |
75a70cf9 | 2736 | stmt = gsi_stmt (i); |
4c5fd53c | 2737 | update_stmt (stmt); |
de6ed584 | 2738 | |
75a70cf9 | 2739 | if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt) |
2740 | && gimple_purge_dead_eh_edges (bb)) | |
b36237eb | 2741 | cfg_changed = true; |
4ee9c684 | 2742 | |
2743 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2744 | { | |
2745 | fprintf (dump_file, "to\n "); | |
75a70cf9 | 2746 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
4ee9c684 | 2747 | fprintf (dump_file, "\n"); |
2748 | } | |
0a39fd54 | 2749 | |
2750 | /* Retry the same statement if it changed into another | |
2751 | builtin, there might be new opportunities now. */ | |
75a70cf9 | 2752 | if (gimple_code (stmt) != GIMPLE_CALL) |
0a39fd54 | 2753 | { |
75a70cf9 | 2754 | gsi_next (&i); |
0a39fd54 | 2755 | continue; |
2756 | } | |
75a70cf9 | 2757 | callee = gimple_call_fndecl (stmt); |
0a39fd54 | 2758 | if (!callee |
75a70cf9 | 2759 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL |
0a39fd54 | 2760 | || DECL_FUNCTION_CODE (callee) == fcode) |
75a70cf9 | 2761 | gsi_next (&i); |
4ee9c684 | 2762 | } |
2763 | } | |
48e1416a | 2764 | |
b36237eb | 2765 | /* Delete unreachable blocks. */ |
b1b7c0c4 | 2766 | if (cfg_changed) |
2767 | todoflags |= TODO_cleanup_cfg; | |
48e1416a | 2768 | |
b1b7c0c4 | 2769 | return todoflags; |
4ee9c684 | 2770 | } |
2771 | ||
cbe8bda8 | 2772 | } // anon namespace |
2773 | ||
2774 | gimple_opt_pass * | |
2775 | make_pass_fold_builtins (gcc::context *ctxt) | |
2776 | { | |
2777 | return new pass_fold_builtins (ctxt); | |
2778 | } |