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4ee9c684 | 1 | /* Conditional constant propagation pass for the GNU compiler. |
711789cc | 2 | Copyright (C) 2000-2013 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 | ||
4ee9c684 | 101 | References: |
102 | ||
103 | Constant propagation with conditional branches, | |
104 | Wegman and Zadeck, ACM TOPLAS 13(2):181-210. | |
105 | ||
106 | Building an Optimizing Compiler, | |
107 | Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9. | |
108 | ||
109 | Advanced Compiler Design and Implementation, | |
110 | Steven Muchnick, Morgan Kaufmann, 1997, Section 12.6 */ | |
111 | ||
112 | #include "config.h" | |
113 | #include "system.h" | |
114 | #include "coretypes.h" | |
115 | #include "tm.h" | |
4ee9c684 | 116 | #include "tree.h" |
9ed99284 | 117 | #include "stor-layout.h" |
41511585 | 118 | #include "flags.h" |
4ee9c684 | 119 | #include "tm_p.h" |
4ee9c684 | 120 | #include "basic-block.h" |
41511585 | 121 | #include "function.h" |
ce084dfc | 122 | #include "gimple-pretty-print.h" |
e795d6e1 | 123 | #include "gimple.h" |
a8783bee | 124 | #include "gimplify.h" |
dcf1a1ec | 125 | #include "gimple-iterator.h" |
073c1fd5 | 126 | #include "gimple-ssa.h" |
127 | #include "tree-cfg.h" | |
128 | #include "tree-phinodes.h" | |
129 | #include "ssa-iterators.h" | |
9ed99284 | 130 | #include "stringpool.h" |
073c1fd5 | 131 | #include "tree-ssanames.h" |
4ee9c684 | 132 | #include "tree-pass.h" |
41511585 | 133 | #include "tree-ssa-propagate.h" |
5a4b7e1e | 134 | #include "value-prof.h" |
41511585 | 135 | #include "langhooks.h" |
8782adcf | 136 | #include "target.h" |
0b205f4c | 137 | #include "diagnostic-core.h" |
43fb76c1 | 138 | #include "dbgcnt.h" |
9a65cc0a | 139 | #include "params.h" |
2b15d2ba | 140 | #include "hash-table.h" |
4ee9c684 | 141 | |
142 | ||
143 | /* Possible lattice values. */ | |
144 | typedef enum | |
145 | { | |
bfa30570 | 146 | UNINITIALIZED, |
4ee9c684 | 147 | UNDEFINED, |
148 | CONSTANT, | |
149 | VARYING | |
88dbf20f | 150 | } ccp_lattice_t; |
4ee9c684 | 151 | |
14f101cf | 152 | struct prop_value_d { |
153 | /* Lattice value. */ | |
154 | ccp_lattice_t lattice_val; | |
155 | ||
156 | /* Propagated value. */ | |
157 | tree value; | |
b7e55469 | 158 | |
159 | /* Mask that applies to the propagated value during CCP. For | |
160 | X with a CONSTANT lattice value X & ~mask == value & ~mask. */ | |
161 | double_int mask; | |
14f101cf | 162 | }; |
163 | ||
164 | typedef struct prop_value_d prop_value_t; | |
165 | ||
88dbf20f | 166 | /* Array of propagated constant values. After propagation, |
167 | CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If | |
168 | the constant is held in an SSA name representing a memory store | |
4fb5e5ca | 169 | (i.e., a VDEF), CONST_VAL[I].MEM_REF will contain the actual |
170 | memory reference used to store (i.e., the LHS of the assignment | |
171 | doing the store). */ | |
20140406 | 172 | static prop_value_t *const_val; |
285df01b | 173 | static unsigned n_const_val; |
4ee9c684 | 174 | |
f5faab84 | 175 | static void canonicalize_value (prop_value_t *); |
6688f8ec | 176 | static bool ccp_fold_stmt (gimple_stmt_iterator *); |
4af351a8 | 177 | |
88dbf20f | 178 | /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */ |
01406fc0 | 179 | |
180 | static void | |
88dbf20f | 181 | dump_lattice_value (FILE *outf, const char *prefix, prop_value_t val) |
01406fc0 | 182 | { |
41511585 | 183 | switch (val.lattice_val) |
01406fc0 | 184 | { |
88dbf20f | 185 | case UNINITIALIZED: |
186 | fprintf (outf, "%sUNINITIALIZED", prefix); | |
187 | break; | |
41511585 | 188 | case UNDEFINED: |
189 | fprintf (outf, "%sUNDEFINED", prefix); | |
190 | break; | |
191 | case VARYING: | |
192 | fprintf (outf, "%sVARYING", prefix); | |
193 | break; | |
41511585 | 194 | case CONSTANT: |
b7e55469 | 195 | if (TREE_CODE (val.value) != INTEGER_CST |
cf8f0e63 | 196 | || val.mask.is_zero ()) |
16ab4e97 | 197 | { |
198 | fprintf (outf, "%sCONSTANT ", prefix); | |
199 | print_generic_expr (outf, val.value, dump_flags); | |
200 | } | |
b7e55469 | 201 | else |
202 | { | |
cf8f0e63 | 203 | double_int cval = tree_to_double_int (val.value).and_not (val.mask); |
b7e55469 | 204 | fprintf (outf, "%sCONSTANT " HOST_WIDE_INT_PRINT_DOUBLE_HEX, |
205 | prefix, cval.high, cval.low); | |
206 | fprintf (outf, " (" HOST_WIDE_INT_PRINT_DOUBLE_HEX ")", | |
207 | val.mask.high, val.mask.low); | |
208 | } | |
41511585 | 209 | break; |
210 | default: | |
8c0963c4 | 211 | gcc_unreachable (); |
41511585 | 212 | } |
01406fc0 | 213 | } |
4ee9c684 | 214 | |
4ee9c684 | 215 | |
88dbf20f | 216 | /* Print lattice value VAL to stderr. */ |
217 | ||
218 | void debug_lattice_value (prop_value_t val); | |
219 | ||
4b987fac | 220 | DEBUG_FUNCTION void |
88dbf20f | 221 | debug_lattice_value (prop_value_t val) |
222 | { | |
223 | dump_lattice_value (stderr, "", val); | |
224 | fprintf (stderr, "\n"); | |
225 | } | |
4ee9c684 | 226 | |
4ee9c684 | 227 | |
88dbf20f | 228 | /* Compute a default value for variable VAR and store it in the |
229 | CONST_VAL array. The following rules are used to get default | |
230 | values: | |
01406fc0 | 231 | |
88dbf20f | 232 | 1- Global and static variables that are declared constant are |
233 | considered CONSTANT. | |
234 | ||
235 | 2- Any other value is considered UNDEFINED. This is useful when | |
41511585 | 236 | considering PHI nodes. PHI arguments that are undefined do not |
237 | change the constant value of the PHI node, which allows for more | |
88dbf20f | 238 | constants to be propagated. |
4ee9c684 | 239 | |
8883e700 | 240 | 3- Variables defined by statements other than assignments and PHI |
88dbf20f | 241 | nodes are considered VARYING. |
4ee9c684 | 242 | |
8883e700 | 243 | 4- Initial values of variables that are not GIMPLE registers are |
bfa30570 | 244 | considered VARYING. */ |
4ee9c684 | 245 | |
88dbf20f | 246 | static prop_value_t |
247 | get_default_value (tree var) | |
248 | { | |
b7e55469 | 249 | prop_value_t val = { UNINITIALIZED, NULL_TREE, { 0, 0 } }; |
8edeb88b | 250 | gimple stmt; |
251 | ||
252 | stmt = SSA_NAME_DEF_STMT (var); | |
253 | ||
254 | if (gimple_nop_p (stmt)) | |
4ee9c684 | 255 | { |
8edeb88b | 256 | /* Variables defined by an empty statement are those used |
257 | before being initialized. If VAR is a local variable, we | |
258 | can assume initially that it is UNDEFINED, otherwise we must | |
259 | consider it VARYING. */ | |
7c782c9b | 260 | if (!virtual_operand_p (var) |
261 | && TREE_CODE (SSA_NAME_VAR (var)) == VAR_DECL) | |
8edeb88b | 262 | val.lattice_val = UNDEFINED; |
263 | else | |
b7e55469 | 264 | { |
265 | val.lattice_val = VARYING; | |
266 | val.mask = double_int_minus_one; | |
fc08b993 | 267 | if (flag_tree_bit_ccp) |
268 | { | |
269 | double_int nonzero_bits = get_nonzero_bits (var); | |
270 | double_int mask | |
271 | = double_int::mask (TYPE_PRECISION (TREE_TYPE (var))); | |
272 | if (nonzero_bits != double_int_minus_one && nonzero_bits != mask) | |
273 | { | |
274 | val.lattice_val = CONSTANT; | |
275 | val.value = build_zero_cst (TREE_TYPE (var)); | |
276 | /* CCP wants the bits above precision set. */ | |
277 | val.mask = nonzero_bits | ~mask; | |
278 | } | |
279 | } | |
b7e55469 | 280 | } |
4ee9c684 | 281 | } |
b45b214a | 282 | else if (is_gimple_assign (stmt)) |
41511585 | 283 | { |
8edeb88b | 284 | tree cst; |
285 | if (gimple_assign_single_p (stmt) | |
286 | && DECL_P (gimple_assign_rhs1 (stmt)) | |
287 | && (cst = get_symbol_constant_value (gimple_assign_rhs1 (stmt)))) | |
88dbf20f | 288 | { |
8edeb88b | 289 | val.lattice_val = CONSTANT; |
290 | val.value = cst; | |
88dbf20f | 291 | } |
292 | else | |
b45b214a | 293 | { |
294 | /* Any other variable defined by an assignment is considered | |
295 | UNDEFINED. */ | |
296 | val.lattice_val = UNDEFINED; | |
297 | } | |
298 | } | |
299 | else if ((is_gimple_call (stmt) | |
300 | && gimple_call_lhs (stmt) != NULL_TREE) | |
301 | || gimple_code (stmt) == GIMPLE_PHI) | |
302 | { | |
303 | /* A variable defined by a call or a PHI node is considered | |
304 | UNDEFINED. */ | |
305 | val.lattice_val = UNDEFINED; | |
8edeb88b | 306 | } |
307 | else | |
308 | { | |
309 | /* Otherwise, VAR will never take on a constant value. */ | |
310 | val.lattice_val = VARYING; | |
b7e55469 | 311 | val.mask = double_int_minus_one; |
41511585 | 312 | } |
4ee9c684 | 313 | |
41511585 | 314 | return val; |
315 | } | |
4ee9c684 | 316 | |
4ee9c684 | 317 | |
bfa30570 | 318 | /* Get the constant value associated with variable VAR. */ |
4ee9c684 | 319 | |
bfa30570 | 320 | static inline prop_value_t * |
321 | get_value (tree var) | |
88dbf20f | 322 | { |
e004838d | 323 | prop_value_t *val; |
bfa30570 | 324 | |
285df01b | 325 | if (const_val == NULL |
326 | || SSA_NAME_VERSION (var) >= n_const_val) | |
e004838d | 327 | return NULL; |
328 | ||
329 | val = &const_val[SSA_NAME_VERSION (var)]; | |
bfa30570 | 330 | if (val->lattice_val == UNINITIALIZED) |
4ee9c684 | 331 | *val = get_default_value (var); |
332 | ||
f5faab84 | 333 | canonicalize_value (val); |
4af351a8 | 334 | |
4ee9c684 | 335 | return val; |
336 | } | |
337 | ||
15d138c9 | 338 | /* Return the constant tree value associated with VAR. */ |
339 | ||
340 | static inline tree | |
341 | get_constant_value (tree var) | |
342 | { | |
98d92e3c | 343 | prop_value_t *val; |
344 | if (TREE_CODE (var) != SSA_NAME) | |
345 | { | |
346 | if (is_gimple_min_invariant (var)) | |
347 | return var; | |
348 | return NULL_TREE; | |
349 | } | |
350 | val = get_value (var); | |
b7e55469 | 351 | if (val |
352 | && val->lattice_val == CONSTANT | |
353 | && (TREE_CODE (val->value) != INTEGER_CST | |
cf8f0e63 | 354 | || val->mask.is_zero ())) |
15d138c9 | 355 | return val->value; |
356 | return NULL_TREE; | |
357 | } | |
358 | ||
bfa30570 | 359 | /* Sets the value associated with VAR to VARYING. */ |
360 | ||
361 | static inline void | |
362 | set_value_varying (tree var) | |
363 | { | |
364 | prop_value_t *val = &const_val[SSA_NAME_VERSION (var)]; | |
365 | ||
366 | val->lattice_val = VARYING; | |
367 | val->value = NULL_TREE; | |
b7e55469 | 368 | val->mask = double_int_minus_one; |
bfa30570 | 369 | } |
4ee9c684 | 370 | |
b31eb493 | 371 | /* For float types, modify the value of VAL to make ccp work correctly |
372 | for non-standard values (-0, NaN): | |
373 | ||
374 | If HONOR_SIGNED_ZEROS is false, and VAL = -0, we canonicalize it to 0. | |
375 | If HONOR_NANS is false, and VAL is NaN, we canonicalize it to UNDEFINED. | |
376 | This is to fix the following problem (see PR 29921): Suppose we have | |
377 | ||
378 | x = 0.0 * y | |
379 | ||
380 | and we set value of y to NaN. This causes value of x to be set to NaN. | |
381 | When we later determine that y is in fact VARYING, fold uses the fact | |
382 | that HONOR_NANS is false, and we try to change the value of x to 0, | |
383 | causing an ICE. With HONOR_NANS being false, the real appearance of | |
384 | NaN would cause undefined behavior, though, so claiming that y (and x) | |
f5faab84 | 385 | are UNDEFINED initially is correct. |
386 | ||
387 | For other constants, make sure to drop TREE_OVERFLOW. */ | |
b31eb493 | 388 | |
389 | static void | |
f5faab84 | 390 | canonicalize_value (prop_value_t *val) |
b31eb493 | 391 | { |
392 | enum machine_mode mode; | |
393 | tree type; | |
394 | REAL_VALUE_TYPE d; | |
395 | ||
f5faab84 | 396 | if (val->lattice_val != CONSTANT) |
397 | return; | |
398 | ||
399 | if (TREE_OVERFLOW_P (val->value)) | |
400 | val->value = drop_tree_overflow (val->value); | |
401 | ||
402 | if (TREE_CODE (val->value) != REAL_CST) | |
b31eb493 | 403 | return; |
404 | ||
405 | d = TREE_REAL_CST (val->value); | |
406 | type = TREE_TYPE (val->value); | |
407 | mode = TYPE_MODE (type); | |
408 | ||
409 | if (!HONOR_SIGNED_ZEROS (mode) | |
410 | && REAL_VALUE_MINUS_ZERO (d)) | |
411 | { | |
412 | val->value = build_real (type, dconst0); | |
413 | return; | |
414 | } | |
415 | ||
416 | if (!HONOR_NANS (mode) | |
417 | && REAL_VALUE_ISNAN (d)) | |
418 | { | |
419 | val->lattice_val = UNDEFINED; | |
420 | val->value = NULL; | |
b31eb493 | 421 | return; |
422 | } | |
423 | } | |
424 | ||
b7e55469 | 425 | /* Return whether the lattice transition is valid. */ |
426 | ||
427 | static bool | |
428 | valid_lattice_transition (prop_value_t old_val, prop_value_t new_val) | |
429 | { | |
430 | /* Lattice transitions must always be monotonically increasing in | |
431 | value. */ | |
432 | if (old_val.lattice_val < new_val.lattice_val) | |
433 | return true; | |
434 | ||
435 | if (old_val.lattice_val != new_val.lattice_val) | |
436 | return false; | |
437 | ||
438 | if (!old_val.value && !new_val.value) | |
439 | return true; | |
440 | ||
441 | /* Now both lattice values are CONSTANT. */ | |
442 | ||
43c92e0a | 443 | /* Allow transitioning from PHI <&x, not executable> == &x |
444 | to PHI <&x, &y> == common alignment. */ | |
b7e55469 | 445 | if (TREE_CODE (old_val.value) != INTEGER_CST |
446 | && TREE_CODE (new_val.value) == INTEGER_CST) | |
447 | return true; | |
448 | ||
449 | /* Bit-lattices have to agree in the still valid bits. */ | |
450 | if (TREE_CODE (old_val.value) == INTEGER_CST | |
451 | && TREE_CODE (new_val.value) == INTEGER_CST) | |
cf8f0e63 | 452 | return tree_to_double_int (old_val.value).and_not (new_val.mask) |
453 | == tree_to_double_int (new_val.value).and_not (new_val.mask); | |
b7e55469 | 454 | |
455 | /* Otherwise constant values have to agree. */ | |
456 | return operand_equal_p (old_val.value, new_val.value, 0); | |
457 | } | |
458 | ||
88dbf20f | 459 | /* Set the value for variable VAR to NEW_VAL. Return true if the new |
460 | value is different from VAR's previous value. */ | |
4ee9c684 | 461 | |
41511585 | 462 | static bool |
88dbf20f | 463 | set_lattice_value (tree var, prop_value_t new_val) |
4ee9c684 | 464 | { |
6d0bf6d6 | 465 | /* We can deal with old UNINITIALIZED values just fine here. */ |
466 | prop_value_t *old_val = &const_val[SSA_NAME_VERSION (var)]; | |
88dbf20f | 467 | |
f5faab84 | 468 | canonicalize_value (&new_val); |
b31eb493 | 469 | |
b7e55469 | 470 | /* We have to be careful to not go up the bitwise lattice |
471 | represented by the mask. | |
472 | ??? This doesn't seem to be the best place to enforce this. */ | |
473 | if (new_val.lattice_val == CONSTANT | |
474 | && old_val->lattice_val == CONSTANT | |
475 | && TREE_CODE (new_val.value) == INTEGER_CST | |
476 | && TREE_CODE (old_val->value) == INTEGER_CST) | |
477 | { | |
478 | double_int diff; | |
cf8f0e63 | 479 | diff = tree_to_double_int (new_val.value) |
480 | ^ tree_to_double_int (old_val->value); | |
481 | new_val.mask = new_val.mask | old_val->mask | diff; | |
b7e55469 | 482 | } |
bfa30570 | 483 | |
b7e55469 | 484 | gcc_assert (valid_lattice_transition (*old_val, new_val)); |
88dbf20f | 485 | |
b7e55469 | 486 | /* If *OLD_VAL and NEW_VAL are the same, return false to inform the |
487 | caller that this was a non-transition. */ | |
488 | if (old_val->lattice_val != new_val.lattice_val | |
489 | || (new_val.lattice_val == CONSTANT | |
490 | && TREE_CODE (new_val.value) == INTEGER_CST | |
491 | && (TREE_CODE (old_val->value) != INTEGER_CST | |
cf8f0e63 | 492 | || new_val.mask != old_val->mask))) |
4ee9c684 | 493 | { |
b7e55469 | 494 | /* ??? We would like to delay creation of INTEGER_CSTs from |
495 | partially constants here. */ | |
496 | ||
41511585 | 497 | if (dump_file && (dump_flags & TDF_DETAILS)) |
498 | { | |
88dbf20f | 499 | dump_lattice_value (dump_file, "Lattice value changed to ", new_val); |
bfa30570 | 500 | fprintf (dump_file, ". Adding SSA edges to worklist.\n"); |
41511585 | 501 | } |
502 | ||
88dbf20f | 503 | *old_val = new_val; |
504 | ||
6d0bf6d6 | 505 | gcc_assert (new_val.lattice_val != UNINITIALIZED); |
bfa30570 | 506 | return true; |
4ee9c684 | 507 | } |
41511585 | 508 | |
509 | return false; | |
4ee9c684 | 510 | } |
511 | ||
b7e55469 | 512 | static prop_value_t get_value_for_expr (tree, bool); |
513 | static prop_value_t bit_value_binop (enum tree_code, tree, tree, tree); | |
514 | static void bit_value_binop_1 (enum tree_code, tree, double_int *, double_int *, | |
515 | tree, double_int, double_int, | |
516 | tree, double_int, double_int); | |
517 | ||
518 | /* Return a double_int that can be used for bitwise simplifications | |
519 | from VAL. */ | |
520 | ||
521 | static double_int | |
522 | value_to_double_int (prop_value_t val) | |
523 | { | |
524 | if (val.value | |
525 | && TREE_CODE (val.value) == INTEGER_CST) | |
526 | return tree_to_double_int (val.value); | |
527 | else | |
528 | return double_int_zero; | |
529 | } | |
530 | ||
531 | /* Return the value for the address expression EXPR based on alignment | |
532 | information. */ | |
6d0bf6d6 | 533 | |
534 | static prop_value_t | |
b7e55469 | 535 | get_value_from_alignment (tree expr) |
536 | { | |
f8abb542 | 537 | tree type = TREE_TYPE (expr); |
b7e55469 | 538 | prop_value_t val; |
f8abb542 | 539 | unsigned HOST_WIDE_INT bitpos; |
540 | unsigned int align; | |
b7e55469 | 541 | |
542 | gcc_assert (TREE_CODE (expr) == ADDR_EXPR); | |
543 | ||
59da1bcd | 544 | get_pointer_alignment_1 (expr, &align, &bitpos); |
cf8f0e63 | 545 | val.mask = (POINTER_TYPE_P (type) || TYPE_UNSIGNED (type) |
546 | ? double_int::mask (TYPE_PRECISION (type)) | |
547 | : double_int_minus_one) | |
548 | .and_not (double_int::from_uhwi (align / BITS_PER_UNIT - 1)); | |
549 | val.lattice_val = val.mask.is_minus_one () ? VARYING : CONSTANT; | |
f8abb542 | 550 | if (val.lattice_val == CONSTANT) |
551 | val.value | |
cf8f0e63 | 552 | = double_int_to_tree (type, |
553 | double_int::from_uhwi (bitpos / BITS_PER_UNIT)); | |
b7e55469 | 554 | else |
f8abb542 | 555 | val.value = NULL_TREE; |
b7e55469 | 556 | |
557 | return val; | |
558 | } | |
559 | ||
560 | /* Return the value for the tree operand EXPR. If FOR_BITS_P is true | |
561 | return constant bits extracted from alignment information for | |
562 | invariant addresses. */ | |
563 | ||
564 | static prop_value_t | |
565 | get_value_for_expr (tree expr, bool for_bits_p) | |
6d0bf6d6 | 566 | { |
567 | prop_value_t val; | |
568 | ||
569 | if (TREE_CODE (expr) == SSA_NAME) | |
b7e55469 | 570 | { |
571 | val = *get_value (expr); | |
572 | if (for_bits_p | |
573 | && val.lattice_val == CONSTANT | |
574 | && TREE_CODE (val.value) == ADDR_EXPR) | |
575 | val = get_value_from_alignment (val.value); | |
576 | } | |
577 | else if (is_gimple_min_invariant (expr) | |
578 | && (!for_bits_p || TREE_CODE (expr) != ADDR_EXPR)) | |
6d0bf6d6 | 579 | { |
580 | val.lattice_val = CONSTANT; | |
581 | val.value = expr; | |
b7e55469 | 582 | val.mask = double_int_zero; |
f5faab84 | 583 | canonicalize_value (&val); |
6d0bf6d6 | 584 | } |
b7e55469 | 585 | else if (TREE_CODE (expr) == ADDR_EXPR) |
586 | val = get_value_from_alignment (expr); | |
6d0bf6d6 | 587 | else |
588 | { | |
589 | val.lattice_val = VARYING; | |
b7e55469 | 590 | val.mask = double_int_minus_one; |
6d0bf6d6 | 591 | val.value = NULL_TREE; |
592 | } | |
6d0bf6d6 | 593 | return val; |
594 | } | |
595 | ||
88dbf20f | 596 | /* Return the likely CCP lattice value for STMT. |
4ee9c684 | 597 | |
41511585 | 598 | If STMT has no operands, then return CONSTANT. |
4ee9c684 | 599 | |
d61b9af3 | 600 | Else if undefinedness of operands of STMT cause its value to be |
601 | undefined, then return UNDEFINED. | |
4ee9c684 | 602 | |
41511585 | 603 | Else if any operands of STMT are constants, then return CONSTANT. |
4ee9c684 | 604 | |
41511585 | 605 | Else return VARYING. */ |
4ee9c684 | 606 | |
88dbf20f | 607 | static ccp_lattice_t |
75a70cf9 | 608 | likely_value (gimple stmt) |
41511585 | 609 | { |
d61b9af3 | 610 | bool has_constant_operand, has_undefined_operand, all_undefined_operands; |
41511585 | 611 | tree use; |
612 | ssa_op_iter iter; | |
8edeb88b | 613 | unsigned i; |
4ee9c684 | 614 | |
590c3166 | 615 | enum gimple_code code = gimple_code (stmt); |
75a70cf9 | 616 | |
617 | /* This function appears to be called only for assignments, calls, | |
618 | conditionals, and switches, due to the logic in visit_stmt. */ | |
619 | gcc_assert (code == GIMPLE_ASSIGN | |
620 | || code == GIMPLE_CALL | |
621 | || code == GIMPLE_COND | |
622 | || code == GIMPLE_SWITCH); | |
88dbf20f | 623 | |
624 | /* If the statement has volatile operands, it won't fold to a | |
625 | constant value. */ | |
75a70cf9 | 626 | if (gimple_has_volatile_ops (stmt)) |
88dbf20f | 627 | return VARYING; |
628 | ||
75a70cf9 | 629 | /* Arrive here for more complex cases. */ |
bfa30570 | 630 | has_constant_operand = false; |
d61b9af3 | 631 | has_undefined_operand = false; |
632 | all_undefined_operands = true; | |
8edeb88b | 633 | FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE) |
41511585 | 634 | { |
bfa30570 | 635 | prop_value_t *val = get_value (use); |
41511585 | 636 | |
bfa30570 | 637 | if (val->lattice_val == UNDEFINED) |
d61b9af3 | 638 | has_undefined_operand = true; |
639 | else | |
640 | all_undefined_operands = false; | |
88dbf20f | 641 | |
41511585 | 642 | if (val->lattice_val == CONSTANT) |
bfa30570 | 643 | has_constant_operand = true; |
4ee9c684 | 644 | } |
41511585 | 645 | |
dd277d48 | 646 | /* There may be constants in regular rhs operands. For calls we |
647 | have to ignore lhs, fndecl and static chain, otherwise only | |
648 | the lhs. */ | |
649 | for (i = (is_gimple_call (stmt) ? 2 : 0) + gimple_has_lhs (stmt); | |
8edeb88b | 650 | i < gimple_num_ops (stmt); ++i) |
651 | { | |
652 | tree op = gimple_op (stmt, i); | |
653 | if (!op || TREE_CODE (op) == SSA_NAME) | |
654 | continue; | |
655 | if (is_gimple_min_invariant (op)) | |
656 | has_constant_operand = true; | |
657 | } | |
658 | ||
87c0a9fc | 659 | if (has_constant_operand) |
660 | all_undefined_operands = false; | |
661 | ||
3d483a94 | 662 | if (has_undefined_operand |
663 | && code == GIMPLE_CALL | |
664 | && gimple_call_internal_p (stmt)) | |
665 | switch (gimple_call_internal_fn (stmt)) | |
666 | { | |
667 | /* These 3 builtins use the first argument just as a magic | |
668 | way how to find out a decl uid. */ | |
669 | case IFN_GOMP_SIMD_LANE: | |
670 | case IFN_GOMP_SIMD_VF: | |
671 | case IFN_GOMP_SIMD_LAST_LANE: | |
672 | has_undefined_operand = false; | |
673 | break; | |
674 | default: | |
675 | break; | |
676 | } | |
677 | ||
d61b9af3 | 678 | /* If the operation combines operands like COMPLEX_EXPR make sure to |
679 | not mark the result UNDEFINED if only one part of the result is | |
680 | undefined. */ | |
75a70cf9 | 681 | if (has_undefined_operand && all_undefined_operands) |
d61b9af3 | 682 | return UNDEFINED; |
75a70cf9 | 683 | else if (code == GIMPLE_ASSIGN && has_undefined_operand) |
d61b9af3 | 684 | { |
75a70cf9 | 685 | switch (gimple_assign_rhs_code (stmt)) |
d61b9af3 | 686 | { |
687 | /* Unary operators are handled with all_undefined_operands. */ | |
688 | case PLUS_EXPR: | |
689 | case MINUS_EXPR: | |
d61b9af3 | 690 | case POINTER_PLUS_EXPR: |
d61b9af3 | 691 | /* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected. |
692 | Not bitwise operators, one VARYING operand may specify the | |
693 | result completely. Not logical operators for the same reason. | |
05a936a0 | 694 | Not COMPLEX_EXPR as one VARYING operand makes the result partly |
695 | not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because | |
696 | the undefined operand may be promoted. */ | |
d61b9af3 | 697 | return UNDEFINED; |
698 | ||
43c92e0a | 699 | case ADDR_EXPR: |
700 | /* If any part of an address is UNDEFINED, like the index | |
701 | of an ARRAY_EXPR, then treat the result as UNDEFINED. */ | |
702 | return UNDEFINED; | |
703 | ||
d61b9af3 | 704 | default: |
705 | ; | |
706 | } | |
707 | } | |
708 | /* If there was an UNDEFINED operand but the result may be not UNDEFINED | |
c91fedc5 | 709 | fall back to CONSTANT. During iteration UNDEFINED may still drop |
710 | to CONSTANT. */ | |
d61b9af3 | 711 | if (has_undefined_operand) |
c91fedc5 | 712 | return CONSTANT; |
d61b9af3 | 713 | |
8edeb88b | 714 | /* We do not consider virtual operands here -- load from read-only |
715 | memory may have only VARYING virtual operands, but still be | |
716 | constant. */ | |
bfa30570 | 717 | if (has_constant_operand |
8edeb88b | 718 | || gimple_references_memory_p (stmt)) |
88dbf20f | 719 | return CONSTANT; |
720 | ||
bfa30570 | 721 | return VARYING; |
4ee9c684 | 722 | } |
723 | ||
bfa30570 | 724 | /* Returns true if STMT cannot be constant. */ |
725 | ||
726 | static bool | |
75a70cf9 | 727 | surely_varying_stmt_p (gimple stmt) |
bfa30570 | 728 | { |
729 | /* If the statement has operands that we cannot handle, it cannot be | |
730 | constant. */ | |
75a70cf9 | 731 | if (gimple_has_volatile_ops (stmt)) |
bfa30570 | 732 | return true; |
733 | ||
f257af64 | 734 | /* If it is a call and does not return a value or is not a |
735 | builtin and not an indirect call, it is varying. */ | |
75a70cf9 | 736 | if (is_gimple_call (stmt)) |
f257af64 | 737 | { |
738 | tree fndecl; | |
739 | if (!gimple_call_lhs (stmt) | |
740 | || ((fndecl = gimple_call_fndecl (stmt)) != NULL_TREE | |
5768aeb3 | 741 | && !DECL_BUILT_IN (fndecl))) |
f257af64 | 742 | return true; |
743 | } | |
bfa30570 | 744 | |
8edeb88b | 745 | /* Any other store operation is not interesting. */ |
dd277d48 | 746 | else if (gimple_vdef (stmt)) |
8edeb88b | 747 | return true; |
748 | ||
bfa30570 | 749 | /* Anything other than assignments and conditional jumps are not |
750 | interesting for CCP. */ | |
75a70cf9 | 751 | if (gimple_code (stmt) != GIMPLE_ASSIGN |
f257af64 | 752 | && gimple_code (stmt) != GIMPLE_COND |
753 | && gimple_code (stmt) != GIMPLE_SWITCH | |
754 | && gimple_code (stmt) != GIMPLE_CALL) | |
bfa30570 | 755 | return true; |
756 | ||
757 | return false; | |
758 | } | |
4ee9c684 | 759 | |
41511585 | 760 | /* Initialize local data structures for CCP. */ |
4ee9c684 | 761 | |
762 | static void | |
41511585 | 763 | ccp_initialize (void) |
4ee9c684 | 764 | { |
41511585 | 765 | basic_block bb; |
4ee9c684 | 766 | |
285df01b | 767 | n_const_val = num_ssa_names; |
768 | const_val = XCNEWVEC (prop_value_t, n_const_val); | |
4ee9c684 | 769 | |
41511585 | 770 | /* Initialize simulation flags for PHI nodes and statements. */ |
771 | FOR_EACH_BB (bb) | |
4ee9c684 | 772 | { |
75a70cf9 | 773 | gimple_stmt_iterator i; |
4ee9c684 | 774 | |
75a70cf9 | 775 | for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) |
41511585 | 776 | { |
75a70cf9 | 777 | gimple stmt = gsi_stmt (i); |
2193544e | 778 | bool is_varying; |
779 | ||
780 | /* If the statement is a control insn, then we do not | |
781 | want to avoid simulating the statement once. Failure | |
782 | to do so means that those edges will never get added. */ | |
783 | if (stmt_ends_bb_p (stmt)) | |
784 | is_varying = false; | |
785 | else | |
786 | is_varying = surely_varying_stmt_p (stmt); | |
4ee9c684 | 787 | |
bfa30570 | 788 | if (is_varying) |
41511585 | 789 | { |
88dbf20f | 790 | tree def; |
791 | ssa_op_iter iter; | |
792 | ||
793 | /* If the statement will not produce a constant, mark | |
794 | all its outputs VARYING. */ | |
795 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) | |
8edeb88b | 796 | set_value_varying (def); |
41511585 | 797 | } |
75a70cf9 | 798 | prop_set_simulate_again (stmt, !is_varying); |
41511585 | 799 | } |
4ee9c684 | 800 | } |
801 | ||
75a70cf9 | 802 | /* Now process PHI nodes. We never clear the simulate_again flag on |
803 | phi nodes, since we do not know which edges are executable yet, | |
804 | except for phi nodes for virtual operands when we do not do store ccp. */ | |
41511585 | 805 | FOR_EACH_BB (bb) |
4ee9c684 | 806 | { |
75a70cf9 | 807 | gimple_stmt_iterator i; |
41511585 | 808 | |
75a70cf9 | 809 | for (i = gsi_start_phis (bb); !gsi_end_p (i); gsi_next (&i)) |
810 | { | |
811 | gimple phi = gsi_stmt (i); | |
812 | ||
7c782c9b | 813 | if (virtual_operand_p (gimple_phi_result (phi))) |
75a70cf9 | 814 | prop_set_simulate_again (phi, false); |
bfa30570 | 815 | else |
75a70cf9 | 816 | prop_set_simulate_again (phi, true); |
41511585 | 817 | } |
4ee9c684 | 818 | } |
41511585 | 819 | } |
4ee9c684 | 820 | |
43fb76c1 | 821 | /* Debug count support. Reset the values of ssa names |
822 | VARYING when the total number ssa names analyzed is | |
823 | beyond the debug count specified. */ | |
824 | ||
825 | static void | |
826 | do_dbg_cnt (void) | |
827 | { | |
828 | unsigned i; | |
829 | for (i = 0; i < num_ssa_names; i++) | |
830 | { | |
831 | if (!dbg_cnt (ccp)) | |
832 | { | |
833 | const_val[i].lattice_val = VARYING; | |
b7e55469 | 834 | const_val[i].mask = double_int_minus_one; |
43fb76c1 | 835 | const_val[i].value = NULL_TREE; |
836 | } | |
837 | } | |
838 | } | |
839 | ||
4ee9c684 | 840 | |
88dbf20f | 841 | /* Do final substitution of propagated values, cleanup the flowgraph and |
48e1416a | 842 | free allocated storage. |
4ee9c684 | 843 | |
33a34f1e | 844 | Return TRUE when something was optimized. */ |
845 | ||
846 | static bool | |
88dbf20f | 847 | ccp_finalize (void) |
4ee9c684 | 848 | { |
43fb76c1 | 849 | bool something_changed; |
153c3b50 | 850 | unsigned i; |
43fb76c1 | 851 | |
852 | do_dbg_cnt (); | |
153c3b50 | 853 | |
854 | /* Derive alignment and misalignment information from partially | |
fc08b993 | 855 | constant pointers in the lattice or nonzero bits from partially |
856 | constant integers. */ | |
153c3b50 | 857 | for (i = 1; i < num_ssa_names; ++i) |
858 | { | |
859 | tree name = ssa_name (i); | |
860 | prop_value_t *val; | |
153c3b50 | 861 | unsigned int tem, align; |
862 | ||
863 | if (!name | |
fc08b993 | 864 | || (!POINTER_TYPE_P (TREE_TYPE (name)) |
865 | && (!INTEGRAL_TYPE_P (TREE_TYPE (name)) | |
866 | /* Don't record nonzero bits before IPA to avoid | |
867 | using too much memory. */ | |
868 | || first_pass_instance))) | |
153c3b50 | 869 | continue; |
870 | ||
871 | val = get_value (name); | |
872 | if (val->lattice_val != CONSTANT | |
873 | || TREE_CODE (val->value) != INTEGER_CST) | |
874 | continue; | |
875 | ||
fc08b993 | 876 | if (POINTER_TYPE_P (TREE_TYPE (name))) |
877 | { | |
878 | /* Trailing mask bits specify the alignment, trailing value | |
879 | bits the misalignment. */ | |
880 | tem = val->mask.low; | |
881 | align = (tem & -tem); | |
882 | if (align > 1) | |
883 | set_ptr_info_alignment (get_ptr_info (name), align, | |
884 | (TREE_INT_CST_LOW (val->value) | |
885 | & (align - 1))); | |
886 | } | |
887 | else | |
888 | { | |
889 | double_int nonzero_bits = val->mask; | |
890 | nonzero_bits = nonzero_bits | tree_to_double_int (val->value); | |
891 | nonzero_bits &= get_nonzero_bits (name); | |
892 | set_nonzero_bits (name, nonzero_bits); | |
893 | } | |
153c3b50 | 894 | } |
895 | ||
88dbf20f | 896 | /* Perform substitutions based on the known constant values. */ |
14f101cf | 897 | something_changed = substitute_and_fold (get_constant_value, |
898 | ccp_fold_stmt, true); | |
4ee9c684 | 899 | |
88dbf20f | 900 | free (const_val); |
e004838d | 901 | const_val = NULL; |
33a34f1e | 902 | return something_changed;; |
4ee9c684 | 903 | } |
904 | ||
905 | ||
88dbf20f | 906 | /* Compute the meet operator between *VAL1 and *VAL2. Store the result |
907 | in VAL1. | |
908 | ||
909 | any M UNDEFINED = any | |
88dbf20f | 910 | any M VARYING = VARYING |
911 | Ci M Cj = Ci if (i == j) | |
912 | Ci M Cj = VARYING if (i != j) | |
bfa30570 | 913 | */ |
4ee9c684 | 914 | |
915 | static void | |
88dbf20f | 916 | ccp_lattice_meet (prop_value_t *val1, prop_value_t *val2) |
4ee9c684 | 917 | { |
88dbf20f | 918 | if (val1->lattice_val == UNDEFINED) |
4ee9c684 | 919 | { |
88dbf20f | 920 | /* UNDEFINED M any = any */ |
921 | *val1 = *val2; | |
41511585 | 922 | } |
88dbf20f | 923 | else if (val2->lattice_val == UNDEFINED) |
92481a4d | 924 | { |
88dbf20f | 925 | /* any M UNDEFINED = any |
926 | Nothing to do. VAL1 already contains the value we want. */ | |
927 | ; | |
92481a4d | 928 | } |
88dbf20f | 929 | else if (val1->lattice_val == VARYING |
930 | || val2->lattice_val == VARYING) | |
41511585 | 931 | { |
88dbf20f | 932 | /* any M VARYING = VARYING. */ |
933 | val1->lattice_val = VARYING; | |
b7e55469 | 934 | val1->mask = double_int_minus_one; |
88dbf20f | 935 | val1->value = NULL_TREE; |
41511585 | 936 | } |
b7e55469 | 937 | else if (val1->lattice_val == CONSTANT |
938 | && val2->lattice_val == CONSTANT | |
939 | && TREE_CODE (val1->value) == INTEGER_CST | |
940 | && TREE_CODE (val2->value) == INTEGER_CST) | |
941 | { | |
942 | /* Ci M Cj = Ci if (i == j) | |
943 | Ci M Cj = VARYING if (i != j) | |
944 | ||
945 | For INTEGER_CSTs mask unequal bits. If no equal bits remain, | |
946 | drop to varying. */ | |
cf8f0e63 | 947 | val1->mask = val1->mask | val2->mask |
948 | | (tree_to_double_int (val1->value) | |
949 | ^ tree_to_double_int (val2->value)); | |
950 | if (val1->mask.is_minus_one ()) | |
b7e55469 | 951 | { |
952 | val1->lattice_val = VARYING; | |
953 | val1->value = NULL_TREE; | |
954 | } | |
955 | } | |
88dbf20f | 956 | else if (val1->lattice_val == CONSTANT |
957 | && val2->lattice_val == CONSTANT | |
61207d43 | 958 | && simple_cst_equal (val1->value, val2->value) == 1) |
41511585 | 959 | { |
88dbf20f | 960 | /* Ci M Cj = Ci if (i == j) |
961 | Ci M Cj = VARYING if (i != j) | |
962 | ||
b7e55469 | 963 | VAL1 already contains the value we want for equivalent values. */ |
964 | } | |
965 | else if (val1->lattice_val == CONSTANT | |
966 | && val2->lattice_val == CONSTANT | |
967 | && (TREE_CODE (val1->value) == ADDR_EXPR | |
968 | || TREE_CODE (val2->value) == ADDR_EXPR)) | |
969 | { | |
970 | /* When not equal addresses are involved try meeting for | |
971 | alignment. */ | |
972 | prop_value_t tem = *val2; | |
973 | if (TREE_CODE (val1->value) == ADDR_EXPR) | |
974 | *val1 = get_value_for_expr (val1->value, true); | |
975 | if (TREE_CODE (val2->value) == ADDR_EXPR) | |
976 | tem = get_value_for_expr (val2->value, true); | |
977 | ccp_lattice_meet (val1, &tem); | |
41511585 | 978 | } |
979 | else | |
980 | { | |
88dbf20f | 981 | /* Any other combination is VARYING. */ |
982 | val1->lattice_val = VARYING; | |
b7e55469 | 983 | val1->mask = double_int_minus_one; |
88dbf20f | 984 | val1->value = NULL_TREE; |
41511585 | 985 | } |
4ee9c684 | 986 | } |
987 | ||
988 | ||
41511585 | 989 | /* Loop through the PHI_NODE's parameters for BLOCK and compare their |
990 | lattice values to determine PHI_NODE's lattice value. The value of a | |
88dbf20f | 991 | PHI node is determined calling ccp_lattice_meet with all the arguments |
41511585 | 992 | of the PHI node that are incoming via executable edges. */ |
4ee9c684 | 993 | |
41511585 | 994 | static enum ssa_prop_result |
75a70cf9 | 995 | ccp_visit_phi_node (gimple phi) |
4ee9c684 | 996 | { |
75a70cf9 | 997 | unsigned i; |
88dbf20f | 998 | prop_value_t *old_val, new_val; |
4ee9c684 | 999 | |
41511585 | 1000 | if (dump_file && (dump_flags & TDF_DETAILS)) |
4ee9c684 | 1001 | { |
41511585 | 1002 | fprintf (dump_file, "\nVisiting PHI node: "); |
75a70cf9 | 1003 | print_gimple_stmt (dump_file, phi, 0, dump_flags); |
4ee9c684 | 1004 | } |
4ee9c684 | 1005 | |
75a70cf9 | 1006 | old_val = get_value (gimple_phi_result (phi)); |
41511585 | 1007 | switch (old_val->lattice_val) |
1008 | { | |
1009 | case VARYING: | |
88dbf20f | 1010 | return SSA_PROP_VARYING; |
4ee9c684 | 1011 | |
41511585 | 1012 | case CONSTANT: |
1013 | new_val = *old_val; | |
1014 | break; | |
4ee9c684 | 1015 | |
41511585 | 1016 | case UNDEFINED: |
41511585 | 1017 | new_val.lattice_val = UNDEFINED; |
88dbf20f | 1018 | new_val.value = NULL_TREE; |
41511585 | 1019 | break; |
4ee9c684 | 1020 | |
41511585 | 1021 | default: |
8c0963c4 | 1022 | gcc_unreachable (); |
41511585 | 1023 | } |
4ee9c684 | 1024 | |
75a70cf9 | 1025 | for (i = 0; i < gimple_phi_num_args (phi); i++) |
41511585 | 1026 | { |
88dbf20f | 1027 | /* Compute the meet operator over all the PHI arguments flowing |
1028 | through executable edges. */ | |
75a70cf9 | 1029 | edge e = gimple_phi_arg_edge (phi, i); |
4ee9c684 | 1030 | |
41511585 | 1031 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1032 | { | |
1033 | fprintf (dump_file, | |
1034 | "\n Argument #%d (%d -> %d %sexecutable)\n", | |
1035 | i, e->src->index, e->dest->index, | |
1036 | (e->flags & EDGE_EXECUTABLE) ? "" : "not "); | |
1037 | } | |
1038 | ||
1039 | /* If the incoming edge is executable, Compute the meet operator for | |
1040 | the existing value of the PHI node and the current PHI argument. */ | |
1041 | if (e->flags & EDGE_EXECUTABLE) | |
1042 | { | |
75a70cf9 | 1043 | tree arg = gimple_phi_arg (phi, i)->def; |
b7e55469 | 1044 | prop_value_t arg_val = get_value_for_expr (arg, false); |
4ee9c684 | 1045 | |
88dbf20f | 1046 | ccp_lattice_meet (&new_val, &arg_val); |
4ee9c684 | 1047 | |
41511585 | 1048 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1049 | { | |
1050 | fprintf (dump_file, "\t"); | |
88dbf20f | 1051 | print_generic_expr (dump_file, arg, dump_flags); |
1052 | dump_lattice_value (dump_file, "\tValue: ", arg_val); | |
41511585 | 1053 | fprintf (dump_file, "\n"); |
1054 | } | |
4ee9c684 | 1055 | |
41511585 | 1056 | if (new_val.lattice_val == VARYING) |
1057 | break; | |
1058 | } | |
1059 | } | |
4ee9c684 | 1060 | |
1061 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
41511585 | 1062 | { |
1063 | dump_lattice_value (dump_file, "\n PHI node value: ", new_val); | |
1064 | fprintf (dump_file, "\n\n"); | |
1065 | } | |
1066 | ||
bfa30570 | 1067 | /* Make the transition to the new value. */ |
75a70cf9 | 1068 | if (set_lattice_value (gimple_phi_result (phi), new_val)) |
41511585 | 1069 | { |
1070 | if (new_val.lattice_val == VARYING) | |
1071 | return SSA_PROP_VARYING; | |
1072 | else | |
1073 | return SSA_PROP_INTERESTING; | |
1074 | } | |
1075 | else | |
1076 | return SSA_PROP_NOT_INTERESTING; | |
4ee9c684 | 1077 | } |
1078 | ||
15d138c9 | 1079 | /* Return the constant value for OP or OP otherwise. */ |
00f4f705 | 1080 | |
1081 | static tree | |
15d138c9 | 1082 | valueize_op (tree op) |
00f4f705 | 1083 | { |
00f4f705 | 1084 | if (TREE_CODE (op) == SSA_NAME) |
1085 | { | |
15d138c9 | 1086 | tree tem = get_constant_value (op); |
1087 | if (tem) | |
1088 | return tem; | |
00f4f705 | 1089 | } |
1090 | return op; | |
1091 | } | |
1092 | ||
41511585 | 1093 | /* CCP specific front-end to the non-destructive constant folding |
1094 | routines. | |
4ee9c684 | 1095 | |
1096 | Attempt to simplify the RHS of STMT knowing that one or more | |
1097 | operands are constants. | |
1098 | ||
1099 | If simplification is possible, return the simplified RHS, | |
75a70cf9 | 1100 | otherwise return the original RHS or NULL_TREE. */ |
4ee9c684 | 1101 | |
1102 | static tree | |
75a70cf9 | 1103 | ccp_fold (gimple stmt) |
4ee9c684 | 1104 | { |
389dd41b | 1105 | location_t loc = gimple_location (stmt); |
75a70cf9 | 1106 | switch (gimple_code (stmt)) |
88dbf20f | 1107 | { |
75a70cf9 | 1108 | case GIMPLE_COND: |
1109 | { | |
1110 | /* Handle comparison operators that can appear in GIMPLE form. */ | |
15d138c9 | 1111 | tree op0 = valueize_op (gimple_cond_lhs (stmt)); |
1112 | tree op1 = valueize_op (gimple_cond_rhs (stmt)); | |
75a70cf9 | 1113 | enum tree_code code = gimple_cond_code (stmt); |
389dd41b | 1114 | return fold_binary_loc (loc, code, boolean_type_node, op0, op1); |
75a70cf9 | 1115 | } |
4ee9c684 | 1116 | |
75a70cf9 | 1117 | case GIMPLE_SWITCH: |
1118 | { | |
15d138c9 | 1119 | /* Return the constant switch index. */ |
1120 | return valueize_op (gimple_switch_index (stmt)); | |
75a70cf9 | 1121 | } |
912f109f | 1122 | |
1d0b727d | 1123 | case GIMPLE_ASSIGN: |
1124 | case GIMPLE_CALL: | |
1125 | return gimple_fold_stmt_to_constant_1 (stmt, valueize_op); | |
04236c3a | 1126 | |
8782adcf | 1127 | default: |
1d0b727d | 1128 | gcc_unreachable (); |
8782adcf | 1129 | } |
8782adcf | 1130 | } |
75a70cf9 | 1131 | |
b7e55469 | 1132 | /* Apply the operation CODE in type TYPE to the value, mask pair |
1133 | RVAL and RMASK representing a value of type RTYPE and set | |
1134 | the value, mask pair *VAL and *MASK to the result. */ | |
1135 | ||
1136 | static void | |
1137 | bit_value_unop_1 (enum tree_code code, tree type, | |
1138 | double_int *val, double_int *mask, | |
1139 | tree rtype, double_int rval, double_int rmask) | |
1140 | { | |
1141 | switch (code) | |
1142 | { | |
1143 | case BIT_NOT_EXPR: | |
1144 | *mask = rmask; | |
cf8f0e63 | 1145 | *val = ~rval; |
b7e55469 | 1146 | break; |
1147 | ||
1148 | case NEGATE_EXPR: | |
1149 | { | |
1150 | double_int temv, temm; | |
1151 | /* Return ~rval + 1. */ | |
1152 | bit_value_unop_1 (BIT_NOT_EXPR, type, &temv, &temm, type, rval, rmask); | |
1153 | bit_value_binop_1 (PLUS_EXPR, type, val, mask, | |
1154 | type, temv, temm, | |
1155 | type, double_int_one, double_int_zero); | |
1156 | break; | |
1157 | } | |
1158 | ||
1159 | CASE_CONVERT: | |
1160 | { | |
1161 | bool uns; | |
1162 | ||
1163 | /* First extend mask and value according to the original type. */ | |
85d86b55 | 1164 | uns = TYPE_UNSIGNED (rtype); |
cf8f0e63 | 1165 | *mask = rmask.ext (TYPE_PRECISION (rtype), uns); |
1166 | *val = rval.ext (TYPE_PRECISION (rtype), uns); | |
b7e55469 | 1167 | |
1168 | /* Then extend mask and value according to the target type. */ | |
85d86b55 | 1169 | uns = TYPE_UNSIGNED (type); |
cf8f0e63 | 1170 | *mask = (*mask).ext (TYPE_PRECISION (type), uns); |
1171 | *val = (*val).ext (TYPE_PRECISION (type), uns); | |
b7e55469 | 1172 | break; |
1173 | } | |
1174 | ||
1175 | default: | |
1176 | *mask = double_int_minus_one; | |
1177 | break; | |
1178 | } | |
1179 | } | |
1180 | ||
1181 | /* Apply the operation CODE in type TYPE to the value, mask pairs | |
1182 | R1VAL, R1MASK and R2VAL, R2MASK representing a values of type R1TYPE | |
1183 | and R2TYPE and set the value, mask pair *VAL and *MASK to the result. */ | |
1184 | ||
1185 | static void | |
1186 | bit_value_binop_1 (enum tree_code code, tree type, | |
1187 | double_int *val, double_int *mask, | |
1188 | tree r1type, double_int r1val, double_int r1mask, | |
1189 | tree r2type, double_int r2val, double_int r2mask) | |
1190 | { | |
85d86b55 | 1191 | bool uns = TYPE_UNSIGNED (type); |
b7e55469 | 1192 | /* Assume we'll get a constant result. Use an initial varying value, |
1193 | we fall back to varying in the end if necessary. */ | |
1194 | *mask = double_int_minus_one; | |
1195 | switch (code) | |
1196 | { | |
1197 | case BIT_AND_EXPR: | |
1198 | /* The mask is constant where there is a known not | |
1199 | set bit, (m1 | m2) & ((v1 | m1) & (v2 | m2)) */ | |
cf8f0e63 | 1200 | *mask = (r1mask | r2mask) & (r1val | r1mask) & (r2val | r2mask); |
1201 | *val = r1val & r2val; | |
b7e55469 | 1202 | break; |
1203 | ||
1204 | case BIT_IOR_EXPR: | |
1205 | /* The mask is constant where there is a known | |
1206 | set bit, (m1 | m2) & ~((v1 & ~m1) | (v2 & ~m2)). */ | |
cf8f0e63 | 1207 | *mask = (r1mask | r2mask) |
1208 | .and_not (r1val.and_not (r1mask) | r2val.and_not (r2mask)); | |
1209 | *val = r1val | r2val; | |
b7e55469 | 1210 | break; |
1211 | ||
1212 | case BIT_XOR_EXPR: | |
1213 | /* m1 | m2 */ | |
cf8f0e63 | 1214 | *mask = r1mask | r2mask; |
1215 | *val = r1val ^ r2val; | |
b7e55469 | 1216 | break; |
1217 | ||
1218 | case LROTATE_EXPR: | |
1219 | case RROTATE_EXPR: | |
cf8f0e63 | 1220 | if (r2mask.is_zero ()) |
b7e55469 | 1221 | { |
1222 | HOST_WIDE_INT shift = r2val.low; | |
1223 | if (code == RROTATE_EXPR) | |
1224 | shift = -shift; | |
cf8f0e63 | 1225 | *mask = r1mask.lrotate (shift, TYPE_PRECISION (type)); |
1226 | *val = r1val.lrotate (shift, TYPE_PRECISION (type)); | |
b7e55469 | 1227 | } |
1228 | break; | |
1229 | ||
1230 | case LSHIFT_EXPR: | |
1231 | case RSHIFT_EXPR: | |
1232 | /* ??? We can handle partially known shift counts if we know | |
1233 | its sign. That way we can tell that (x << (y | 8)) & 255 | |
1234 | is zero. */ | |
cf8f0e63 | 1235 | if (r2mask.is_zero ()) |
b7e55469 | 1236 | { |
1237 | HOST_WIDE_INT shift = r2val.low; | |
1238 | if (code == RSHIFT_EXPR) | |
1239 | shift = -shift; | |
1240 | /* We need to know if we are doing a left or a right shift | |
1241 | to properly shift in zeros for left shift and unsigned | |
1242 | right shifts and the sign bit for signed right shifts. | |
1243 | For signed right shifts we shift in varying in case | |
1244 | the sign bit was varying. */ | |
1245 | if (shift > 0) | |
1246 | { | |
cf8f0e63 | 1247 | *mask = r1mask.llshift (shift, TYPE_PRECISION (type)); |
1248 | *val = r1val.llshift (shift, TYPE_PRECISION (type)); | |
b7e55469 | 1249 | } |
1250 | else if (shift < 0) | |
1251 | { | |
1252 | shift = -shift; | |
cf8f0e63 | 1253 | *mask = r1mask.rshift (shift, TYPE_PRECISION (type), !uns); |
1254 | *val = r1val.rshift (shift, TYPE_PRECISION (type), !uns); | |
b7e55469 | 1255 | } |
1256 | else | |
1257 | { | |
1258 | *mask = r1mask; | |
1259 | *val = r1val; | |
1260 | } | |
1261 | } | |
1262 | break; | |
1263 | ||
1264 | case PLUS_EXPR: | |
1265 | case POINTER_PLUS_EXPR: | |
1266 | { | |
1267 | double_int lo, hi; | |
1268 | /* Do the addition with unknown bits set to zero, to give carry-ins of | |
1269 | zero wherever possible. */ | |
cf8f0e63 | 1270 | lo = r1val.and_not (r1mask) + r2val.and_not (r2mask); |
1271 | lo = lo.ext (TYPE_PRECISION (type), uns); | |
b7e55469 | 1272 | /* Do the addition with unknown bits set to one, to give carry-ins of |
1273 | one wherever possible. */ | |
cf8f0e63 | 1274 | hi = (r1val | r1mask) + (r2val | r2mask); |
1275 | hi = hi.ext (TYPE_PRECISION (type), uns); | |
b7e55469 | 1276 | /* Each bit in the result is known if (a) the corresponding bits in |
1277 | both inputs are known, and (b) the carry-in to that bit position | |
1278 | is known. We can check condition (b) by seeing if we got the same | |
1279 | result with minimised carries as with maximised carries. */ | |
cf8f0e63 | 1280 | *mask = r1mask | r2mask | (lo ^ hi); |
1281 | *mask = (*mask).ext (TYPE_PRECISION (type), uns); | |
b7e55469 | 1282 | /* It shouldn't matter whether we choose lo or hi here. */ |
1283 | *val = lo; | |
1284 | break; | |
1285 | } | |
1286 | ||
1287 | case MINUS_EXPR: | |
1288 | { | |
1289 | double_int temv, temm; | |
1290 | bit_value_unop_1 (NEGATE_EXPR, r2type, &temv, &temm, | |
1291 | r2type, r2val, r2mask); | |
1292 | bit_value_binop_1 (PLUS_EXPR, type, val, mask, | |
1293 | r1type, r1val, r1mask, | |
1294 | r2type, temv, temm); | |
1295 | break; | |
1296 | } | |
1297 | ||
1298 | case MULT_EXPR: | |
1299 | { | |
1300 | /* Just track trailing zeros in both operands and transfer | |
1301 | them to the other. */ | |
cf8f0e63 | 1302 | int r1tz = (r1val | r1mask).trailing_zeros (); |
1303 | int r2tz = (r2val | r2mask).trailing_zeros (); | |
b7e55469 | 1304 | if (r1tz + r2tz >= HOST_BITS_PER_DOUBLE_INT) |
1305 | { | |
1306 | *mask = double_int_zero; | |
1307 | *val = double_int_zero; | |
1308 | } | |
1309 | else if (r1tz + r2tz > 0) | |
1310 | { | |
cf8f0e63 | 1311 | *mask = ~double_int::mask (r1tz + r2tz); |
1312 | *mask = (*mask).ext (TYPE_PRECISION (type), uns); | |
b7e55469 | 1313 | *val = double_int_zero; |
1314 | } | |
1315 | break; | |
1316 | } | |
1317 | ||
1318 | case EQ_EXPR: | |
1319 | case NE_EXPR: | |
1320 | { | |
cf8f0e63 | 1321 | double_int m = r1mask | r2mask; |
1322 | if (r1val.and_not (m) != r2val.and_not (m)) | |
b7e55469 | 1323 | { |
1324 | *mask = double_int_zero; | |
1325 | *val = ((code == EQ_EXPR) ? double_int_zero : double_int_one); | |
1326 | } | |
1327 | else | |
1328 | { | |
1329 | /* We know the result of a comparison is always one or zero. */ | |
1330 | *mask = double_int_one; | |
1331 | *val = double_int_zero; | |
1332 | } | |
1333 | break; | |
1334 | } | |
1335 | ||
1336 | case GE_EXPR: | |
1337 | case GT_EXPR: | |
1338 | { | |
1339 | double_int tem = r1val; | |
1340 | r1val = r2val; | |
1341 | r2val = tem; | |
1342 | tem = r1mask; | |
1343 | r1mask = r2mask; | |
1344 | r2mask = tem; | |
1345 | code = swap_tree_comparison (code); | |
1346 | } | |
1347 | /* Fallthru. */ | |
1348 | case LT_EXPR: | |
1349 | case LE_EXPR: | |
1350 | { | |
1351 | int minmax, maxmin; | |
1352 | /* If the most significant bits are not known we know nothing. */ | |
cf8f0e63 | 1353 | if (r1mask.is_negative () || r2mask.is_negative ()) |
b7e55469 | 1354 | break; |
1355 | ||
90c0f5b7 | 1356 | /* For comparisons the signedness is in the comparison operands. */ |
85d86b55 | 1357 | uns = TYPE_UNSIGNED (r1type); |
90c0f5b7 | 1358 | |
b7e55469 | 1359 | /* If we know the most significant bits we know the values |
1360 | value ranges by means of treating varying bits as zero | |
1361 | or one. Do a cross comparison of the max/min pairs. */ | |
cf8f0e63 | 1362 | maxmin = (r1val | r1mask).cmp (r2val.and_not (r2mask), uns); |
1363 | minmax = r1val.and_not (r1mask).cmp (r2val | r2mask, uns); | |
b7e55469 | 1364 | if (maxmin < 0) /* r1 is less than r2. */ |
1365 | { | |
1366 | *mask = double_int_zero; | |
1367 | *val = double_int_one; | |
1368 | } | |
1369 | else if (minmax > 0) /* r1 is not less or equal to r2. */ | |
1370 | { | |
1371 | *mask = double_int_zero; | |
1372 | *val = double_int_zero; | |
1373 | } | |
1374 | else if (maxmin == minmax) /* r1 and r2 are equal. */ | |
1375 | { | |
1376 | /* This probably should never happen as we'd have | |
1377 | folded the thing during fully constant value folding. */ | |
1378 | *mask = double_int_zero; | |
1379 | *val = (code == LE_EXPR ? double_int_one : double_int_zero); | |
1380 | } | |
1381 | else | |
1382 | { | |
1383 | /* We know the result of a comparison is always one or zero. */ | |
1384 | *mask = double_int_one; | |
1385 | *val = double_int_zero; | |
1386 | } | |
1387 | break; | |
1388 | } | |
1389 | ||
1390 | default:; | |
1391 | } | |
1392 | } | |
1393 | ||
1394 | /* Return the propagation value when applying the operation CODE to | |
1395 | the value RHS yielding type TYPE. */ | |
1396 | ||
1397 | static prop_value_t | |
1398 | bit_value_unop (enum tree_code code, tree type, tree rhs) | |
1399 | { | |
1400 | prop_value_t rval = get_value_for_expr (rhs, true); | |
1401 | double_int value, mask; | |
1402 | prop_value_t val; | |
c91fedc5 | 1403 | |
1404 | if (rval.lattice_val == UNDEFINED) | |
1405 | return rval; | |
1406 | ||
b7e55469 | 1407 | gcc_assert ((rval.lattice_val == CONSTANT |
1408 | && TREE_CODE (rval.value) == INTEGER_CST) | |
cf8f0e63 | 1409 | || rval.mask.is_minus_one ()); |
b7e55469 | 1410 | bit_value_unop_1 (code, type, &value, &mask, |
1411 | TREE_TYPE (rhs), value_to_double_int (rval), rval.mask); | |
cf8f0e63 | 1412 | if (!mask.is_minus_one ()) |
b7e55469 | 1413 | { |
1414 | val.lattice_val = CONSTANT; | |
1415 | val.mask = mask; | |
1416 | /* ??? Delay building trees here. */ | |
1417 | val.value = double_int_to_tree (type, value); | |
1418 | } | |
1419 | else | |
1420 | { | |
1421 | val.lattice_val = VARYING; | |
1422 | val.value = NULL_TREE; | |
1423 | val.mask = double_int_minus_one; | |
1424 | } | |
1425 | return val; | |
1426 | } | |
1427 | ||
1428 | /* Return the propagation value when applying the operation CODE to | |
1429 | the values RHS1 and RHS2 yielding type TYPE. */ | |
1430 | ||
1431 | static prop_value_t | |
1432 | bit_value_binop (enum tree_code code, tree type, tree rhs1, tree rhs2) | |
1433 | { | |
1434 | prop_value_t r1val = get_value_for_expr (rhs1, true); | |
1435 | prop_value_t r2val = get_value_for_expr (rhs2, true); | |
1436 | double_int value, mask; | |
1437 | prop_value_t val; | |
c91fedc5 | 1438 | |
1439 | if (r1val.lattice_val == UNDEFINED | |
1440 | || r2val.lattice_val == UNDEFINED) | |
1441 | { | |
1442 | val.lattice_val = VARYING; | |
1443 | val.value = NULL_TREE; | |
1444 | val.mask = double_int_minus_one; | |
1445 | return val; | |
1446 | } | |
1447 | ||
b7e55469 | 1448 | gcc_assert ((r1val.lattice_val == CONSTANT |
1449 | && TREE_CODE (r1val.value) == INTEGER_CST) | |
cf8f0e63 | 1450 | || r1val.mask.is_minus_one ()); |
b7e55469 | 1451 | gcc_assert ((r2val.lattice_val == CONSTANT |
1452 | && TREE_CODE (r2val.value) == INTEGER_CST) | |
cf8f0e63 | 1453 | || r2val.mask.is_minus_one ()); |
b7e55469 | 1454 | bit_value_binop_1 (code, type, &value, &mask, |
1455 | TREE_TYPE (rhs1), value_to_double_int (r1val), r1val.mask, | |
1456 | TREE_TYPE (rhs2), value_to_double_int (r2val), r2val.mask); | |
cf8f0e63 | 1457 | if (!mask.is_minus_one ()) |
b7e55469 | 1458 | { |
1459 | val.lattice_val = CONSTANT; | |
1460 | val.mask = mask; | |
1461 | /* ??? Delay building trees here. */ | |
1462 | val.value = double_int_to_tree (type, value); | |
1463 | } | |
1464 | else | |
1465 | { | |
1466 | val.lattice_val = VARYING; | |
1467 | val.value = NULL_TREE; | |
1468 | val.mask = double_int_minus_one; | |
1469 | } | |
1470 | return val; | |
1471 | } | |
1472 | ||
fca0886c | 1473 | /* Return the propagation value when applying __builtin_assume_aligned to |
1474 | its arguments. */ | |
1475 | ||
1476 | static prop_value_t | |
1477 | bit_value_assume_aligned (gimple stmt) | |
1478 | { | |
1479 | tree ptr = gimple_call_arg (stmt, 0), align, misalign = NULL_TREE; | |
1480 | tree type = TREE_TYPE (ptr); | |
1481 | unsigned HOST_WIDE_INT aligni, misaligni = 0; | |
1482 | prop_value_t ptrval = get_value_for_expr (ptr, true); | |
1483 | prop_value_t alignval; | |
1484 | double_int value, mask; | |
1485 | prop_value_t val; | |
1486 | if (ptrval.lattice_val == UNDEFINED) | |
1487 | return ptrval; | |
1488 | gcc_assert ((ptrval.lattice_val == CONSTANT | |
1489 | && TREE_CODE (ptrval.value) == INTEGER_CST) | |
cf8f0e63 | 1490 | || ptrval.mask.is_minus_one ()); |
fca0886c | 1491 | align = gimple_call_arg (stmt, 1); |
cd4547bf | 1492 | if (!tree_fits_uhwi_p (align)) |
fca0886c | 1493 | return ptrval; |
6a0712d4 | 1494 | aligni = tree_to_uhwi (align); |
fca0886c | 1495 | if (aligni <= 1 |
1496 | || (aligni & (aligni - 1)) != 0) | |
1497 | return ptrval; | |
1498 | if (gimple_call_num_args (stmt) > 2) | |
1499 | { | |
1500 | misalign = gimple_call_arg (stmt, 2); | |
cd4547bf | 1501 | if (!tree_fits_uhwi_p (misalign)) |
fca0886c | 1502 | return ptrval; |
6a0712d4 | 1503 | misaligni = tree_to_uhwi (misalign); |
fca0886c | 1504 | if (misaligni >= aligni) |
1505 | return ptrval; | |
1506 | } | |
1507 | align = build_int_cst_type (type, -aligni); | |
1508 | alignval = get_value_for_expr (align, true); | |
1509 | bit_value_binop_1 (BIT_AND_EXPR, type, &value, &mask, | |
1510 | type, value_to_double_int (ptrval), ptrval.mask, | |
1511 | type, value_to_double_int (alignval), alignval.mask); | |
cf8f0e63 | 1512 | if (!mask.is_minus_one ()) |
fca0886c | 1513 | { |
1514 | val.lattice_val = CONSTANT; | |
1515 | val.mask = mask; | |
1516 | gcc_assert ((mask.low & (aligni - 1)) == 0); | |
1517 | gcc_assert ((value.low & (aligni - 1)) == 0); | |
1518 | value.low |= misaligni; | |
1519 | /* ??? Delay building trees here. */ | |
1520 | val.value = double_int_to_tree (type, value); | |
1521 | } | |
1522 | else | |
1523 | { | |
1524 | val.lattice_val = VARYING; | |
1525 | val.value = NULL_TREE; | |
1526 | val.mask = double_int_minus_one; | |
1527 | } | |
1528 | return val; | |
1529 | } | |
1530 | ||
75a70cf9 | 1531 | /* Evaluate statement STMT. |
1532 | Valid only for assignments, calls, conditionals, and switches. */ | |
4ee9c684 | 1533 | |
88dbf20f | 1534 | static prop_value_t |
75a70cf9 | 1535 | evaluate_stmt (gimple stmt) |
4ee9c684 | 1536 | { |
88dbf20f | 1537 | prop_value_t val; |
4f61cce6 | 1538 | tree simplified = NULL_TREE; |
88dbf20f | 1539 | ccp_lattice_t likelyvalue = likely_value (stmt); |
b7e55469 | 1540 | bool is_constant = false; |
581bf1c2 | 1541 | unsigned int align; |
88dbf20f | 1542 | |
b7e55469 | 1543 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1544 | { | |
1545 | fprintf (dump_file, "which is likely "); | |
1546 | switch (likelyvalue) | |
1547 | { | |
1548 | case CONSTANT: | |
1549 | fprintf (dump_file, "CONSTANT"); | |
1550 | break; | |
1551 | case UNDEFINED: | |
1552 | fprintf (dump_file, "UNDEFINED"); | |
1553 | break; | |
1554 | case VARYING: | |
1555 | fprintf (dump_file, "VARYING"); | |
1556 | break; | |
1557 | default:; | |
1558 | } | |
1559 | fprintf (dump_file, "\n"); | |
1560 | } | |
add6ee5e | 1561 | |
4ee9c684 | 1562 | /* If the statement is likely to have a CONSTANT result, then try |
1563 | to fold the statement to determine the constant value. */ | |
75a70cf9 | 1564 | /* FIXME. This is the only place that we call ccp_fold. |
1565 | Since likely_value never returns CONSTANT for calls, we will | |
1566 | not attempt to fold them, including builtins that may profit. */ | |
4ee9c684 | 1567 | if (likelyvalue == CONSTANT) |
b7e55469 | 1568 | { |
1569 | fold_defer_overflow_warnings (); | |
1570 | simplified = ccp_fold (stmt); | |
1571 | is_constant = simplified && is_gimple_min_invariant (simplified); | |
1572 | fold_undefer_overflow_warnings (is_constant, stmt, 0); | |
1573 | if (is_constant) | |
1574 | { | |
1575 | /* The statement produced a constant value. */ | |
1576 | val.lattice_val = CONSTANT; | |
1577 | val.value = simplified; | |
1578 | val.mask = double_int_zero; | |
1579 | } | |
1580 | } | |
4ee9c684 | 1581 | /* If the statement is likely to have a VARYING result, then do not |
1582 | bother folding the statement. */ | |
04236c3a | 1583 | else if (likelyvalue == VARYING) |
75a70cf9 | 1584 | { |
590c3166 | 1585 | enum gimple_code code = gimple_code (stmt); |
75a70cf9 | 1586 | if (code == GIMPLE_ASSIGN) |
1587 | { | |
1588 | enum tree_code subcode = gimple_assign_rhs_code (stmt); | |
48e1416a | 1589 | |
75a70cf9 | 1590 | /* Other cases cannot satisfy is_gimple_min_invariant |
1591 | without folding. */ | |
1592 | if (get_gimple_rhs_class (subcode) == GIMPLE_SINGLE_RHS) | |
1593 | simplified = gimple_assign_rhs1 (stmt); | |
1594 | } | |
1595 | else if (code == GIMPLE_SWITCH) | |
1596 | simplified = gimple_switch_index (stmt); | |
1597 | else | |
a65c4d64 | 1598 | /* These cannot satisfy is_gimple_min_invariant without folding. */ |
1599 | gcc_assert (code == GIMPLE_CALL || code == GIMPLE_COND); | |
b7e55469 | 1600 | is_constant = simplified && is_gimple_min_invariant (simplified); |
1601 | if (is_constant) | |
1602 | { | |
1603 | /* The statement produced a constant value. */ | |
1604 | val.lattice_val = CONSTANT; | |
1605 | val.value = simplified; | |
1606 | val.mask = double_int_zero; | |
1607 | } | |
75a70cf9 | 1608 | } |
4ee9c684 | 1609 | |
b7e55469 | 1610 | /* Resort to simplification for bitwise tracking. */ |
1611 | if (flag_tree_bit_ccp | |
939514e9 | 1612 | && (likelyvalue == CONSTANT || is_gimple_call (stmt)) |
b7e55469 | 1613 | && !is_constant) |
912f109f | 1614 | { |
b7e55469 | 1615 | enum gimple_code code = gimple_code (stmt); |
1616 | val.lattice_val = VARYING; | |
1617 | val.value = NULL_TREE; | |
1618 | val.mask = double_int_minus_one; | |
1619 | if (code == GIMPLE_ASSIGN) | |
912f109f | 1620 | { |
b7e55469 | 1621 | enum tree_code subcode = gimple_assign_rhs_code (stmt); |
1622 | tree rhs1 = gimple_assign_rhs1 (stmt); | |
1623 | switch (get_gimple_rhs_class (subcode)) | |
1624 | { | |
1625 | case GIMPLE_SINGLE_RHS: | |
1626 | if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
1627 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
1628 | val = get_value_for_expr (rhs1, true); | |
1629 | break; | |
1630 | ||
1631 | case GIMPLE_UNARY_RHS: | |
1632 | if ((INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
1633 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
1634 | && (INTEGRAL_TYPE_P (gimple_expr_type (stmt)) | |
1635 | || POINTER_TYPE_P (gimple_expr_type (stmt)))) | |
1636 | val = bit_value_unop (subcode, gimple_expr_type (stmt), rhs1); | |
1637 | break; | |
1638 | ||
1639 | case GIMPLE_BINARY_RHS: | |
1640 | if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
1641 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
1642 | { | |
e47d81e0 | 1643 | tree lhs = gimple_assign_lhs (stmt); |
b7e55469 | 1644 | tree rhs2 = gimple_assign_rhs2 (stmt); |
1645 | val = bit_value_binop (subcode, | |
e47d81e0 | 1646 | TREE_TYPE (lhs), rhs1, rhs2); |
b7e55469 | 1647 | } |
1648 | break; | |
1649 | ||
1650 | default:; | |
1651 | } | |
912f109f | 1652 | } |
b7e55469 | 1653 | else if (code == GIMPLE_COND) |
1654 | { | |
1655 | enum tree_code code = gimple_cond_code (stmt); | |
1656 | tree rhs1 = gimple_cond_lhs (stmt); | |
1657 | tree rhs2 = gimple_cond_rhs (stmt); | |
1658 | if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
1659 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
1660 | val = bit_value_binop (code, TREE_TYPE (rhs1), rhs1, rhs2); | |
1661 | } | |
0b4f0116 | 1662 | else if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)) |
153c3b50 | 1663 | { |
0b4f0116 | 1664 | tree fndecl = gimple_call_fndecl (stmt); |
153c3b50 | 1665 | switch (DECL_FUNCTION_CODE (fndecl)) |
1666 | { | |
1667 | case BUILT_IN_MALLOC: | |
1668 | case BUILT_IN_REALLOC: | |
1669 | case BUILT_IN_CALLOC: | |
939514e9 | 1670 | case BUILT_IN_STRDUP: |
1671 | case BUILT_IN_STRNDUP: | |
153c3b50 | 1672 | val.lattice_val = CONSTANT; |
1673 | val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0); | |
cf8f0e63 | 1674 | val.mask = double_int::from_shwi |
153c3b50 | 1675 | (~(((HOST_WIDE_INT) MALLOC_ABI_ALIGNMENT) |
1676 | / BITS_PER_UNIT - 1)); | |
1677 | break; | |
1678 | ||
1679 | case BUILT_IN_ALLOCA: | |
581bf1c2 | 1680 | case BUILT_IN_ALLOCA_WITH_ALIGN: |
1681 | align = (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_ALLOCA_WITH_ALIGN | |
1682 | ? TREE_INT_CST_LOW (gimple_call_arg (stmt, 1)) | |
1683 | : BIGGEST_ALIGNMENT); | |
153c3b50 | 1684 | val.lattice_val = CONSTANT; |
1685 | val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0); | |
cf8f0e63 | 1686 | val.mask = double_int::from_shwi (~(((HOST_WIDE_INT) align) |
1687 | / BITS_PER_UNIT - 1)); | |
153c3b50 | 1688 | break; |
1689 | ||
939514e9 | 1690 | /* These builtins return their first argument, unmodified. */ |
1691 | case BUILT_IN_MEMCPY: | |
1692 | case BUILT_IN_MEMMOVE: | |
1693 | case BUILT_IN_MEMSET: | |
1694 | case BUILT_IN_STRCPY: | |
1695 | case BUILT_IN_STRNCPY: | |
1696 | case BUILT_IN_MEMCPY_CHK: | |
1697 | case BUILT_IN_MEMMOVE_CHK: | |
1698 | case BUILT_IN_MEMSET_CHK: | |
1699 | case BUILT_IN_STRCPY_CHK: | |
1700 | case BUILT_IN_STRNCPY_CHK: | |
1701 | val = get_value_for_expr (gimple_call_arg (stmt, 0), true); | |
1702 | break; | |
1703 | ||
fca0886c | 1704 | case BUILT_IN_ASSUME_ALIGNED: |
1705 | val = bit_value_assume_aligned (stmt); | |
1706 | break; | |
1707 | ||
153c3b50 | 1708 | default:; |
1709 | } | |
1710 | } | |
b7e55469 | 1711 | is_constant = (val.lattice_val == CONSTANT); |
912f109f | 1712 | } |
1713 | ||
fc08b993 | 1714 | if (flag_tree_bit_ccp |
1715 | && ((is_constant && TREE_CODE (val.value) == INTEGER_CST) | |
1716 | || (!is_constant && likelyvalue != UNDEFINED)) | |
1717 | && gimple_get_lhs (stmt) | |
1718 | && TREE_CODE (gimple_get_lhs (stmt)) == SSA_NAME) | |
1719 | { | |
1720 | tree lhs = gimple_get_lhs (stmt); | |
1721 | double_int nonzero_bits = get_nonzero_bits (lhs); | |
1722 | double_int mask = double_int::mask (TYPE_PRECISION (TREE_TYPE (lhs))); | |
1723 | if (nonzero_bits != double_int_minus_one && nonzero_bits != mask) | |
1724 | { | |
1725 | if (!is_constant) | |
1726 | { | |
1727 | val.lattice_val = CONSTANT; | |
1728 | val.value = build_zero_cst (TREE_TYPE (lhs)); | |
1729 | /* CCP wants the bits above precision set. */ | |
1730 | val.mask = nonzero_bits | ~mask; | |
1731 | is_constant = true; | |
1732 | } | |
1733 | else | |
1734 | { | |
1735 | double_int valv = tree_to_double_int (val.value); | |
1736 | if (!(valv & ~nonzero_bits & mask).is_zero ()) | |
1737 | val.value = double_int_to_tree (TREE_TYPE (lhs), | |
1738 | valv & nonzero_bits); | |
1739 | if (nonzero_bits.is_zero ()) | |
1740 | val.mask = double_int_zero; | |
1741 | else | |
1742 | val.mask = val.mask & (nonzero_bits | ~mask); | |
1743 | } | |
1744 | } | |
1745 | } | |
1746 | ||
b7e55469 | 1747 | if (!is_constant) |
4ee9c684 | 1748 | { |
1749 | /* The statement produced a nonconstant value. If the statement | |
88dbf20f | 1750 | had UNDEFINED operands, then the result of the statement |
1751 | should be UNDEFINED. Otherwise, the statement is VARYING. */ | |
bfa30570 | 1752 | if (likelyvalue == UNDEFINED) |
b7e55469 | 1753 | { |
1754 | val.lattice_val = likelyvalue; | |
1755 | val.mask = double_int_zero; | |
1756 | } | |
b765fa12 | 1757 | else |
b7e55469 | 1758 | { |
1759 | val.lattice_val = VARYING; | |
1760 | val.mask = double_int_minus_one; | |
1761 | } | |
b765fa12 | 1762 | |
88dbf20f | 1763 | val.value = NULL_TREE; |
4ee9c684 | 1764 | } |
41511585 | 1765 | |
1766 | return val; | |
4ee9c684 | 1767 | } |
1768 | ||
de6bd75e | 1769 | typedef hash_table <pointer_hash <gimple_statement_base> > gimple_htab; |
2b15d2ba | 1770 | |
582a80ed | 1771 | /* Given a BUILT_IN_STACK_SAVE value SAVED_VAL, insert a clobber of VAR before |
1772 | each matching BUILT_IN_STACK_RESTORE. Mark visited phis in VISITED. */ | |
1773 | ||
1774 | static void | |
2b15d2ba | 1775 | insert_clobber_before_stack_restore (tree saved_val, tree var, |
1776 | gimple_htab *visited) | |
582a80ed | 1777 | { |
1778 | gimple stmt, clobber_stmt; | |
1779 | tree clobber; | |
1780 | imm_use_iterator iter; | |
1781 | gimple_stmt_iterator i; | |
1782 | gimple *slot; | |
1783 | ||
1784 | FOR_EACH_IMM_USE_STMT (stmt, iter, saved_val) | |
1785 | if (gimple_call_builtin_p (stmt, BUILT_IN_STACK_RESTORE)) | |
1786 | { | |
f1f41a6c | 1787 | clobber = build_constructor (TREE_TYPE (var), |
1788 | NULL); | |
582a80ed | 1789 | TREE_THIS_VOLATILE (clobber) = 1; |
1790 | clobber_stmt = gimple_build_assign (var, clobber); | |
1791 | ||
1792 | i = gsi_for_stmt (stmt); | |
1793 | gsi_insert_before (&i, clobber_stmt, GSI_SAME_STMT); | |
1794 | } | |
1795 | else if (gimple_code (stmt) == GIMPLE_PHI) | |
1796 | { | |
2b15d2ba | 1797 | if (!visited->is_created ()) |
1798 | visited->create (10); | |
582a80ed | 1799 | |
2b15d2ba | 1800 | slot = visited->find_slot (stmt, INSERT); |
582a80ed | 1801 | if (*slot != NULL) |
1802 | continue; | |
1803 | ||
1804 | *slot = stmt; | |
1805 | insert_clobber_before_stack_restore (gimple_phi_result (stmt), var, | |
1806 | visited); | |
1807 | } | |
42eed683 | 1808 | else if (gimple_assign_ssa_name_copy_p (stmt)) |
1809 | insert_clobber_before_stack_restore (gimple_assign_lhs (stmt), var, | |
1810 | visited); | |
582a80ed | 1811 | else |
1812 | gcc_assert (is_gimple_debug (stmt)); | |
1813 | } | |
1814 | ||
1815 | /* Advance the iterator to the previous non-debug gimple statement in the same | |
1816 | or dominating basic block. */ | |
1817 | ||
1818 | static inline void | |
1819 | gsi_prev_dom_bb_nondebug (gimple_stmt_iterator *i) | |
1820 | { | |
1821 | basic_block dom; | |
1822 | ||
1823 | gsi_prev_nondebug (i); | |
1824 | while (gsi_end_p (*i)) | |
1825 | { | |
1826 | dom = get_immediate_dominator (CDI_DOMINATORS, i->bb); | |
34154e27 | 1827 | if (dom == NULL || dom == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
582a80ed | 1828 | return; |
1829 | ||
1830 | *i = gsi_last_bb (dom); | |
1831 | } | |
1832 | } | |
1833 | ||
1834 | /* Find a BUILT_IN_STACK_SAVE dominating gsi_stmt (I), and insert | |
1543f720 | 1835 | a clobber of VAR before each matching BUILT_IN_STACK_RESTORE. |
1836 | ||
1837 | It is possible that BUILT_IN_STACK_SAVE cannot be find in a dominator when a | |
1838 | previous pass (such as DOM) duplicated it along multiple paths to a BB. In | |
1839 | that case the function gives up without inserting the clobbers. */ | |
582a80ed | 1840 | |
1841 | static void | |
1842 | insert_clobbers_for_var (gimple_stmt_iterator i, tree var) | |
1843 | { | |
582a80ed | 1844 | gimple stmt; |
1845 | tree saved_val; | |
2b15d2ba | 1846 | gimple_htab visited; |
582a80ed | 1847 | |
1543f720 | 1848 | for (; !gsi_end_p (i); gsi_prev_dom_bb_nondebug (&i)) |
582a80ed | 1849 | { |
1850 | stmt = gsi_stmt (i); | |
1851 | ||
1852 | if (!gimple_call_builtin_p (stmt, BUILT_IN_STACK_SAVE)) | |
1853 | continue; | |
582a80ed | 1854 | |
1855 | saved_val = gimple_call_lhs (stmt); | |
1856 | if (saved_val == NULL_TREE) | |
1857 | continue; | |
1858 | ||
1859 | insert_clobber_before_stack_restore (saved_val, var, &visited); | |
1860 | break; | |
1861 | } | |
1862 | ||
2b15d2ba | 1863 | if (visited.is_created ()) |
1864 | visited.dispose (); | |
582a80ed | 1865 | } |
1866 | ||
581bf1c2 | 1867 | /* Detects a __builtin_alloca_with_align with constant size argument. Declares |
1868 | fixed-size array and returns the address, if found, otherwise returns | |
1869 | NULL_TREE. */ | |
9a65cc0a | 1870 | |
1871 | static tree | |
581bf1c2 | 1872 | fold_builtin_alloca_with_align (gimple stmt) |
9a65cc0a | 1873 | { |
1874 | unsigned HOST_WIDE_INT size, threshold, n_elem; | |
1875 | tree lhs, arg, block, var, elem_type, array_type; | |
9a65cc0a | 1876 | |
1877 | /* Get lhs. */ | |
1878 | lhs = gimple_call_lhs (stmt); | |
1879 | if (lhs == NULL_TREE) | |
1880 | return NULL_TREE; | |
1881 | ||
1882 | /* Detect constant argument. */ | |
1883 | arg = get_constant_value (gimple_call_arg (stmt, 0)); | |
6e93d308 | 1884 | if (arg == NULL_TREE |
1885 | || TREE_CODE (arg) != INTEGER_CST | |
cd4547bf | 1886 | || !tree_fits_uhwi_p (arg)) |
9a65cc0a | 1887 | return NULL_TREE; |
6e93d308 | 1888 | |
9a65cc0a | 1889 | size = TREE_INT_CST_LOW (arg); |
1890 | ||
581bf1c2 | 1891 | /* Heuristic: don't fold large allocas. */ |
9a65cc0a | 1892 | threshold = (unsigned HOST_WIDE_INT)PARAM_VALUE (PARAM_LARGE_STACK_FRAME); |
581bf1c2 | 1893 | /* In case the alloca is located at function entry, it has the same lifetime |
1894 | as a declared array, so we allow a larger size. */ | |
9a65cc0a | 1895 | block = gimple_block (stmt); |
1896 | if (!(cfun->after_inlining | |
1897 | && TREE_CODE (BLOCK_SUPERCONTEXT (block)) == FUNCTION_DECL)) | |
1898 | threshold /= 10; | |
1899 | if (size > threshold) | |
1900 | return NULL_TREE; | |
1901 | ||
1902 | /* Declare array. */ | |
1903 | elem_type = build_nonstandard_integer_type (BITS_PER_UNIT, 1); | |
1904 | n_elem = size * 8 / BITS_PER_UNIT; | |
9a65cc0a | 1905 | array_type = build_array_type_nelts (elem_type, n_elem); |
1906 | var = create_tmp_var (array_type, NULL); | |
581bf1c2 | 1907 | DECL_ALIGN (var) = TREE_INT_CST_LOW (gimple_call_arg (stmt, 1)); |
3d4a0a4b | 1908 | { |
1909 | struct ptr_info_def *pi = SSA_NAME_PTR_INFO (lhs); | |
1910 | if (pi != NULL && !pi->pt.anything) | |
1911 | { | |
1912 | bool singleton_p; | |
1913 | unsigned uid; | |
1914 | singleton_p = pt_solution_singleton_p (&pi->pt, &uid); | |
1915 | gcc_assert (singleton_p); | |
1916 | SET_DECL_PT_UID (var, uid); | |
1917 | } | |
1918 | } | |
9a65cc0a | 1919 | |
1920 | /* Fold alloca to the address of the array. */ | |
1921 | return fold_convert (TREE_TYPE (lhs), build_fold_addr_expr (var)); | |
1922 | } | |
1923 | ||
6688f8ec | 1924 | /* Fold the stmt at *GSI with CCP specific information that propagating |
1925 | and regular folding does not catch. */ | |
1926 | ||
1927 | static bool | |
1928 | ccp_fold_stmt (gimple_stmt_iterator *gsi) | |
1929 | { | |
1930 | gimple stmt = gsi_stmt (*gsi); | |
6688f8ec | 1931 | |
94144e68 | 1932 | switch (gimple_code (stmt)) |
1933 | { | |
1934 | case GIMPLE_COND: | |
1935 | { | |
1936 | prop_value_t val; | |
1937 | /* Statement evaluation will handle type mismatches in constants | |
1938 | more gracefully than the final propagation. This allows us to | |
1939 | fold more conditionals here. */ | |
1940 | val = evaluate_stmt (stmt); | |
1941 | if (val.lattice_val != CONSTANT | |
cf8f0e63 | 1942 | || !val.mask.is_zero ()) |
94144e68 | 1943 | return false; |
1944 | ||
b7e55469 | 1945 | if (dump_file) |
1946 | { | |
1947 | fprintf (dump_file, "Folding predicate "); | |
1948 | print_gimple_expr (dump_file, stmt, 0, 0); | |
1949 | fprintf (dump_file, " to "); | |
1950 | print_generic_expr (dump_file, val.value, 0); | |
1951 | fprintf (dump_file, "\n"); | |
1952 | } | |
1953 | ||
94144e68 | 1954 | if (integer_zerop (val.value)) |
1955 | gimple_cond_make_false (stmt); | |
1956 | else | |
1957 | gimple_cond_make_true (stmt); | |
6688f8ec | 1958 | |
94144e68 | 1959 | return true; |
1960 | } | |
6688f8ec | 1961 | |
94144e68 | 1962 | case GIMPLE_CALL: |
1963 | { | |
1964 | tree lhs = gimple_call_lhs (stmt); | |
3064bb7b | 1965 | int flags = gimple_call_flags (stmt); |
15d138c9 | 1966 | tree val; |
94144e68 | 1967 | tree argt; |
1968 | bool changed = false; | |
1969 | unsigned i; | |
1970 | ||
1971 | /* If the call was folded into a constant make sure it goes | |
1972 | away even if we cannot propagate into all uses because of | |
1973 | type issues. */ | |
1974 | if (lhs | |
1975 | && TREE_CODE (lhs) == SSA_NAME | |
3064bb7b | 1976 | && (val = get_constant_value (lhs)) |
1977 | /* Don't optimize away calls that have side-effects. */ | |
1978 | && (flags & (ECF_CONST|ECF_PURE)) != 0 | |
1979 | && (flags & ECF_LOOPING_CONST_OR_PURE) == 0) | |
94144e68 | 1980 | { |
15d138c9 | 1981 | tree new_rhs = unshare_expr (val); |
338cce8f | 1982 | bool res; |
94144e68 | 1983 | if (!useless_type_conversion_p (TREE_TYPE (lhs), |
1984 | TREE_TYPE (new_rhs))) | |
1985 | new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs); | |
338cce8f | 1986 | res = update_call_from_tree (gsi, new_rhs); |
1987 | gcc_assert (res); | |
94144e68 | 1988 | return true; |
1989 | } | |
1990 | ||
fb049fba | 1991 | /* Internal calls provide no argument types, so the extra laxity |
1992 | for normal calls does not apply. */ | |
1993 | if (gimple_call_internal_p (stmt)) | |
1994 | return false; | |
1995 | ||
581bf1c2 | 1996 | /* The heuristic of fold_builtin_alloca_with_align differs before and |
1997 | after inlining, so we don't require the arg to be changed into a | |
1998 | constant for folding, but just to be constant. */ | |
1999 | if (gimple_call_builtin_p (stmt, BUILT_IN_ALLOCA_WITH_ALIGN)) | |
9a65cc0a | 2000 | { |
581bf1c2 | 2001 | tree new_rhs = fold_builtin_alloca_with_align (stmt); |
6e93d308 | 2002 | if (new_rhs) |
2003 | { | |
2004 | bool res = update_call_from_tree (gsi, new_rhs); | |
582a80ed | 2005 | tree var = TREE_OPERAND (TREE_OPERAND (new_rhs, 0),0); |
6e93d308 | 2006 | gcc_assert (res); |
582a80ed | 2007 | insert_clobbers_for_var (*gsi, var); |
6e93d308 | 2008 | return true; |
2009 | } | |
9a65cc0a | 2010 | } |
2011 | ||
94144e68 | 2012 | /* Propagate into the call arguments. Compared to replace_uses_in |
2013 | this can use the argument slot types for type verification | |
2014 | instead of the current argument type. We also can safely | |
2015 | drop qualifiers here as we are dealing with constants anyway. */ | |
2de00a2d | 2016 | argt = TYPE_ARG_TYPES (gimple_call_fntype (stmt)); |
94144e68 | 2017 | for (i = 0; i < gimple_call_num_args (stmt) && argt; |
2018 | ++i, argt = TREE_CHAIN (argt)) | |
2019 | { | |
2020 | tree arg = gimple_call_arg (stmt, i); | |
2021 | if (TREE_CODE (arg) == SSA_NAME | |
15d138c9 | 2022 | && (val = get_constant_value (arg)) |
94144e68 | 2023 | && useless_type_conversion_p |
2024 | (TYPE_MAIN_VARIANT (TREE_VALUE (argt)), | |
15d138c9 | 2025 | TYPE_MAIN_VARIANT (TREE_TYPE (val)))) |
94144e68 | 2026 | { |
15d138c9 | 2027 | gimple_call_set_arg (stmt, i, unshare_expr (val)); |
94144e68 | 2028 | changed = true; |
2029 | } | |
2030 | } | |
e16f4c39 | 2031 | |
94144e68 | 2032 | return changed; |
2033 | } | |
6688f8ec | 2034 | |
6872bf3c | 2035 | case GIMPLE_ASSIGN: |
2036 | { | |
2037 | tree lhs = gimple_assign_lhs (stmt); | |
15d138c9 | 2038 | tree val; |
6872bf3c | 2039 | |
2040 | /* If we have a load that turned out to be constant replace it | |
2041 | as we cannot propagate into all uses in all cases. */ | |
2042 | if (gimple_assign_single_p (stmt) | |
2043 | && TREE_CODE (lhs) == SSA_NAME | |
15d138c9 | 2044 | && (val = get_constant_value (lhs))) |
6872bf3c | 2045 | { |
15d138c9 | 2046 | tree rhs = unshare_expr (val); |
6872bf3c | 2047 | if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs))) |
182cf5a9 | 2048 | rhs = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), rhs); |
6872bf3c | 2049 | gimple_assign_set_rhs_from_tree (gsi, rhs); |
2050 | return true; | |
2051 | } | |
2052 | ||
2053 | return false; | |
2054 | } | |
2055 | ||
94144e68 | 2056 | default: |
2057 | return false; | |
2058 | } | |
6688f8ec | 2059 | } |
2060 | ||
41511585 | 2061 | /* Visit the assignment statement STMT. Set the value of its LHS to the |
88dbf20f | 2062 | value computed by the RHS and store LHS in *OUTPUT_P. If STMT |
2063 | creates virtual definitions, set the value of each new name to that | |
75a70cf9 | 2064 | of the RHS (if we can derive a constant out of the RHS). |
2065 | Value-returning call statements also perform an assignment, and | |
2066 | are handled here. */ | |
4ee9c684 | 2067 | |
41511585 | 2068 | static enum ssa_prop_result |
75a70cf9 | 2069 | visit_assignment (gimple stmt, tree *output_p) |
4ee9c684 | 2070 | { |
88dbf20f | 2071 | prop_value_t val; |
88dbf20f | 2072 | enum ssa_prop_result retval; |
4ee9c684 | 2073 | |
75a70cf9 | 2074 | tree lhs = gimple_get_lhs (stmt); |
4ee9c684 | 2075 | |
75a70cf9 | 2076 | gcc_assert (gimple_code (stmt) != GIMPLE_CALL |
2077 | || gimple_call_lhs (stmt) != NULL_TREE); | |
2078 | ||
15d138c9 | 2079 | if (gimple_assign_single_p (stmt) |
2080 | && gimple_assign_rhs_code (stmt) == SSA_NAME) | |
2081 | /* For a simple copy operation, we copy the lattice values. */ | |
2082 | val = *get_value (gimple_assign_rhs1 (stmt)); | |
41511585 | 2083 | else |
75a70cf9 | 2084 | /* Evaluate the statement, which could be |
2085 | either a GIMPLE_ASSIGN or a GIMPLE_CALL. */ | |
04236c3a | 2086 | val = evaluate_stmt (stmt); |
4ee9c684 | 2087 | |
88dbf20f | 2088 | retval = SSA_PROP_NOT_INTERESTING; |
4ee9c684 | 2089 | |
41511585 | 2090 | /* Set the lattice value of the statement's output. */ |
88dbf20f | 2091 | if (TREE_CODE (lhs) == SSA_NAME) |
4ee9c684 | 2092 | { |
88dbf20f | 2093 | /* If STMT is an assignment to an SSA_NAME, we only have one |
2094 | value to set. */ | |
2095 | if (set_lattice_value (lhs, val)) | |
2096 | { | |
2097 | *output_p = lhs; | |
2098 | if (val.lattice_val == VARYING) | |
2099 | retval = SSA_PROP_VARYING; | |
2100 | else | |
2101 | retval = SSA_PROP_INTERESTING; | |
2102 | } | |
4ee9c684 | 2103 | } |
88dbf20f | 2104 | |
2105 | return retval; | |
4ee9c684 | 2106 | } |
2107 | ||
4ee9c684 | 2108 | |
41511585 | 2109 | /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING |
2110 | if it can determine which edge will be taken. Otherwise, return | |
2111 | SSA_PROP_VARYING. */ | |
2112 | ||
2113 | static enum ssa_prop_result | |
75a70cf9 | 2114 | visit_cond_stmt (gimple stmt, edge *taken_edge_p) |
4ee9c684 | 2115 | { |
88dbf20f | 2116 | prop_value_t val; |
41511585 | 2117 | basic_block block; |
2118 | ||
75a70cf9 | 2119 | block = gimple_bb (stmt); |
41511585 | 2120 | val = evaluate_stmt (stmt); |
b7e55469 | 2121 | if (val.lattice_val != CONSTANT |
cf8f0e63 | 2122 | || !val.mask.is_zero ()) |
b7e55469 | 2123 | return SSA_PROP_VARYING; |
41511585 | 2124 | |
2125 | /* Find which edge out of the conditional block will be taken and add it | |
2126 | to the worklist. If no single edge can be determined statically, | |
2127 | return SSA_PROP_VARYING to feed all the outgoing edges to the | |
2128 | propagation engine. */ | |
b7e55469 | 2129 | *taken_edge_p = find_taken_edge (block, val.value); |
41511585 | 2130 | if (*taken_edge_p) |
2131 | return SSA_PROP_INTERESTING; | |
2132 | else | |
2133 | return SSA_PROP_VARYING; | |
4ee9c684 | 2134 | } |
2135 | ||
4ee9c684 | 2136 | |
41511585 | 2137 | /* Evaluate statement STMT. If the statement produces an output value and |
2138 | its evaluation changes the lattice value of its output, return | |
2139 | SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the | |
2140 | output value. | |
48e1416a | 2141 | |
41511585 | 2142 | If STMT is a conditional branch and we can determine its truth |
2143 | value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying | |
2144 | value, return SSA_PROP_VARYING. */ | |
4ee9c684 | 2145 | |
41511585 | 2146 | static enum ssa_prop_result |
75a70cf9 | 2147 | ccp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p) |
41511585 | 2148 | { |
41511585 | 2149 | tree def; |
2150 | ssa_op_iter iter; | |
4ee9c684 | 2151 | |
41511585 | 2152 | if (dump_file && (dump_flags & TDF_DETAILS)) |
4ee9c684 | 2153 | { |
88dbf20f | 2154 | fprintf (dump_file, "\nVisiting statement:\n"); |
75a70cf9 | 2155 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
4ee9c684 | 2156 | } |
4ee9c684 | 2157 | |
75a70cf9 | 2158 | switch (gimple_code (stmt)) |
4ee9c684 | 2159 | { |
75a70cf9 | 2160 | case GIMPLE_ASSIGN: |
2161 | /* If the statement is an assignment that produces a single | |
2162 | output value, evaluate its RHS to see if the lattice value of | |
2163 | its output has changed. */ | |
2164 | return visit_assignment (stmt, output_p); | |
2165 | ||
2166 | case GIMPLE_CALL: | |
2167 | /* A value-returning call also performs an assignment. */ | |
2168 | if (gimple_call_lhs (stmt) != NULL_TREE) | |
2169 | return visit_assignment (stmt, output_p); | |
2170 | break; | |
2171 | ||
2172 | case GIMPLE_COND: | |
2173 | case GIMPLE_SWITCH: | |
2174 | /* If STMT is a conditional branch, see if we can determine | |
2175 | which branch will be taken. */ | |
2176 | /* FIXME. It appears that we should be able to optimize | |
2177 | computed GOTOs here as well. */ | |
2178 | return visit_cond_stmt (stmt, taken_edge_p); | |
2179 | ||
2180 | default: | |
2181 | break; | |
4ee9c684 | 2182 | } |
4ee9c684 | 2183 | |
41511585 | 2184 | /* Any other kind of statement is not interesting for constant |
2185 | propagation and, therefore, not worth simulating. */ | |
41511585 | 2186 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2187 | fprintf (dump_file, "No interesting values produced. Marked VARYING.\n"); | |
4ee9c684 | 2188 | |
41511585 | 2189 | /* Definitions made by statements other than assignments to |
2190 | SSA_NAMEs represent unknown modifications to their outputs. | |
2191 | Mark them VARYING. */ | |
88dbf20f | 2192 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) |
2193 | { | |
b7e55469 | 2194 | prop_value_t v = { VARYING, NULL_TREE, { -1, (HOST_WIDE_INT) -1 } }; |
88dbf20f | 2195 | set_lattice_value (def, v); |
2196 | } | |
4ee9c684 | 2197 | |
41511585 | 2198 | return SSA_PROP_VARYING; |
2199 | } | |
4ee9c684 | 2200 | |
4ee9c684 | 2201 | |
88dbf20f | 2202 | /* Main entry point for SSA Conditional Constant Propagation. */ |
41511585 | 2203 | |
33a34f1e | 2204 | static unsigned int |
61207d43 | 2205 | do_ssa_ccp (void) |
41511585 | 2206 | { |
582a80ed | 2207 | unsigned int todo = 0; |
2208 | calculate_dominance_info (CDI_DOMINATORS); | |
41511585 | 2209 | ccp_initialize (); |
2210 | ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node); | |
33a34f1e | 2211 | if (ccp_finalize ()) |
560965e9 | 2212 | todo = (TODO_cleanup_cfg | TODO_update_ssa); |
582a80ed | 2213 | free_dominance_info (CDI_DOMINATORS); |
2214 | return todo; | |
4ee9c684 | 2215 | } |
2216 | ||
5664499b | 2217 | |
2218 | static bool | |
41511585 | 2219 | gate_ccp (void) |
5664499b | 2220 | { |
41511585 | 2221 | return flag_tree_ccp != 0; |
5664499b | 2222 | } |
2223 | ||
4ee9c684 | 2224 | |
cbe8bda8 | 2225 | namespace { |
2226 | ||
2227 | const pass_data pass_data_ccp = | |
41511585 | 2228 | { |
cbe8bda8 | 2229 | GIMPLE_PASS, /* type */ |
2230 | "ccp", /* name */ | |
2231 | OPTGROUP_NONE, /* optinfo_flags */ | |
2232 | true, /* has_gate */ | |
2233 | true, /* has_execute */ | |
2234 | TV_TREE_CCP, /* tv_id */ | |
2235 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
2236 | 0, /* properties_provided */ | |
2237 | 0, /* properties_destroyed */ | |
2238 | 0, /* todo_flags_start */ | |
2239 | ( TODO_verify_ssa | TODO_update_address_taken | |
2240 | | TODO_verify_stmts ), /* todo_flags_finish */ | |
41511585 | 2241 | }; |
4ee9c684 | 2242 | |
cbe8bda8 | 2243 | class pass_ccp : public gimple_opt_pass |
2244 | { | |
2245 | public: | |
9af5ce0c | 2246 | pass_ccp (gcc::context *ctxt) |
2247 | : gimple_opt_pass (pass_data_ccp, ctxt) | |
cbe8bda8 | 2248 | {} |
2249 | ||
2250 | /* opt_pass methods: */ | |
ae84f584 | 2251 | opt_pass * clone () { return new pass_ccp (m_ctxt); } |
cbe8bda8 | 2252 | bool gate () { return gate_ccp (); } |
2253 | unsigned int execute () { return do_ssa_ccp (); } | |
2254 | ||
2255 | }; // class pass_ccp | |
2256 | ||
2257 | } // anon namespace | |
2258 | ||
2259 | gimple_opt_pass * | |
2260 | make_pass_ccp (gcc::context *ctxt) | |
2261 | { | |
2262 | return new pass_ccp (ctxt); | |
2263 | } | |
2264 | ||
4ee9c684 | 2265 | |
75a70cf9 | 2266 | |
bdd0e199 | 2267 | /* Try to optimize out __builtin_stack_restore. Optimize it out |
2268 | if there is another __builtin_stack_restore in the same basic | |
2269 | block and no calls or ASM_EXPRs are in between, or if this block's | |
2270 | only outgoing edge is to EXIT_BLOCK and there are no calls or | |
2271 | ASM_EXPRs after this __builtin_stack_restore. */ | |
2272 | ||
2273 | static tree | |
75a70cf9 | 2274 | optimize_stack_restore (gimple_stmt_iterator i) |
bdd0e199 | 2275 | { |
6ea999da | 2276 | tree callee; |
2277 | gimple stmt; | |
75a70cf9 | 2278 | |
2279 | basic_block bb = gsi_bb (i); | |
2280 | gimple call = gsi_stmt (i); | |
bdd0e199 | 2281 | |
75a70cf9 | 2282 | if (gimple_code (call) != GIMPLE_CALL |
2283 | || gimple_call_num_args (call) != 1 | |
2284 | || TREE_CODE (gimple_call_arg (call, 0)) != SSA_NAME | |
2285 | || !POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call, 0)))) | |
bdd0e199 | 2286 | return NULL_TREE; |
2287 | ||
75a70cf9 | 2288 | for (gsi_next (&i); !gsi_end_p (i); gsi_next (&i)) |
bdd0e199 | 2289 | { |
75a70cf9 | 2290 | stmt = gsi_stmt (i); |
2291 | if (gimple_code (stmt) == GIMPLE_ASM) | |
bdd0e199 | 2292 | return NULL_TREE; |
75a70cf9 | 2293 | if (gimple_code (stmt) != GIMPLE_CALL) |
bdd0e199 | 2294 | continue; |
2295 | ||
75a70cf9 | 2296 | callee = gimple_call_fndecl (stmt); |
c40a6f90 | 2297 | if (!callee |
2298 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL | |
2299 | /* All regular builtins are ok, just obviously not alloca. */ | |
581bf1c2 | 2300 | || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA |
2301 | || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA_WITH_ALIGN) | |
bdd0e199 | 2302 | return NULL_TREE; |
2303 | ||
2304 | if (DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_RESTORE) | |
6ea999da | 2305 | goto second_stack_restore; |
bdd0e199 | 2306 | } |
2307 | ||
6ea999da | 2308 | if (!gsi_end_p (i)) |
bdd0e199 | 2309 | return NULL_TREE; |
2310 | ||
6ea999da | 2311 | /* Allow one successor of the exit block, or zero successors. */ |
2312 | switch (EDGE_COUNT (bb->succs)) | |
2313 | { | |
2314 | case 0: | |
2315 | break; | |
2316 | case 1: | |
34154e27 | 2317 | if (single_succ_edge (bb)->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
6ea999da | 2318 | return NULL_TREE; |
2319 | break; | |
2320 | default: | |
2321 | return NULL_TREE; | |
2322 | } | |
2323 | second_stack_restore: | |
bdd0e199 | 2324 | |
6ea999da | 2325 | /* If there's exactly one use, then zap the call to __builtin_stack_save. |
2326 | If there are multiple uses, then the last one should remove the call. | |
2327 | In any case, whether the call to __builtin_stack_save can be removed | |
2328 | or not is irrelevant to removing the call to __builtin_stack_restore. */ | |
2329 | if (has_single_use (gimple_call_arg (call, 0))) | |
2330 | { | |
2331 | gimple stack_save = SSA_NAME_DEF_STMT (gimple_call_arg (call, 0)); | |
2332 | if (is_gimple_call (stack_save)) | |
2333 | { | |
2334 | callee = gimple_call_fndecl (stack_save); | |
2335 | if (callee | |
2336 | && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL | |
2337 | && DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_SAVE) | |
2338 | { | |
2339 | gimple_stmt_iterator stack_save_gsi; | |
2340 | tree rhs; | |
bdd0e199 | 2341 | |
6ea999da | 2342 | stack_save_gsi = gsi_for_stmt (stack_save); |
2343 | rhs = build_int_cst (TREE_TYPE (gimple_call_arg (call, 0)), 0); | |
2344 | update_call_from_tree (&stack_save_gsi, rhs); | |
2345 | } | |
2346 | } | |
2347 | } | |
bdd0e199 | 2348 | |
75a70cf9 | 2349 | /* No effect, so the statement will be deleted. */ |
bdd0e199 | 2350 | return integer_zero_node; |
2351 | } | |
75a70cf9 | 2352 | |
8a58ed0a | 2353 | /* If va_list type is a simple pointer and nothing special is needed, |
2354 | optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0), | |
2355 | __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple | |
2356 | pointer assignment. */ | |
2357 | ||
2358 | static tree | |
75a70cf9 | 2359 | optimize_stdarg_builtin (gimple call) |
8a58ed0a | 2360 | { |
5f57a8b1 | 2361 | tree callee, lhs, rhs, cfun_va_list; |
8a58ed0a | 2362 | bool va_list_simple_ptr; |
389dd41b | 2363 | location_t loc = gimple_location (call); |
8a58ed0a | 2364 | |
75a70cf9 | 2365 | if (gimple_code (call) != GIMPLE_CALL) |
8a58ed0a | 2366 | return NULL_TREE; |
2367 | ||
75a70cf9 | 2368 | callee = gimple_call_fndecl (call); |
5f57a8b1 | 2369 | |
2370 | cfun_va_list = targetm.fn_abi_va_list (callee); | |
2371 | va_list_simple_ptr = POINTER_TYPE_P (cfun_va_list) | |
2372 | && (TREE_TYPE (cfun_va_list) == void_type_node | |
2373 | || TREE_TYPE (cfun_va_list) == char_type_node); | |
2374 | ||
8a58ed0a | 2375 | switch (DECL_FUNCTION_CODE (callee)) |
2376 | { | |
2377 | case BUILT_IN_VA_START: | |
2378 | if (!va_list_simple_ptr | |
2379 | || targetm.expand_builtin_va_start != NULL | |
e7ed5dd7 | 2380 | || !builtin_decl_explicit_p (BUILT_IN_NEXT_ARG)) |
8a58ed0a | 2381 | return NULL_TREE; |
2382 | ||
75a70cf9 | 2383 | if (gimple_call_num_args (call) != 2) |
8a58ed0a | 2384 | return NULL_TREE; |
2385 | ||
75a70cf9 | 2386 | lhs = gimple_call_arg (call, 0); |
8a58ed0a | 2387 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) |
2388 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
5f57a8b1 | 2389 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
8a58ed0a | 2390 | return NULL_TREE; |
48e1416a | 2391 | |
389dd41b | 2392 | lhs = build_fold_indirect_ref_loc (loc, lhs); |
b9a16870 | 2393 | rhs = build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_NEXT_ARG), |
75a70cf9 | 2394 | 1, integer_zero_node); |
389dd41b | 2395 | rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); |
8a58ed0a | 2396 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); |
2397 | ||
2398 | case BUILT_IN_VA_COPY: | |
2399 | if (!va_list_simple_ptr) | |
2400 | return NULL_TREE; | |
2401 | ||
75a70cf9 | 2402 | if (gimple_call_num_args (call) != 2) |
8a58ed0a | 2403 | return NULL_TREE; |
2404 | ||
75a70cf9 | 2405 | lhs = gimple_call_arg (call, 0); |
8a58ed0a | 2406 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) |
2407 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
5f57a8b1 | 2408 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
8a58ed0a | 2409 | return NULL_TREE; |
2410 | ||
389dd41b | 2411 | lhs = build_fold_indirect_ref_loc (loc, lhs); |
75a70cf9 | 2412 | rhs = gimple_call_arg (call, 1); |
8a58ed0a | 2413 | if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs)) |
5f57a8b1 | 2414 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
8a58ed0a | 2415 | return NULL_TREE; |
2416 | ||
389dd41b | 2417 | rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); |
8a58ed0a | 2418 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); |
2419 | ||
2420 | case BUILT_IN_VA_END: | |
75a70cf9 | 2421 | /* No effect, so the statement will be deleted. */ |
8a58ed0a | 2422 | return integer_zero_node; |
2423 | ||
2424 | default: | |
2425 | gcc_unreachable (); | |
2426 | } | |
2427 | } | |
75a70cf9 | 2428 | |
f87df69a | 2429 | /* Attemp to make the block of __builtin_unreachable I unreachable by changing |
2430 | the incoming jumps. Return true if at least one jump was changed. */ | |
2431 | ||
2432 | static bool | |
2433 | optimize_unreachable (gimple_stmt_iterator i) | |
2434 | { | |
2435 | basic_block bb = gsi_bb (i); | |
2436 | gimple_stmt_iterator gsi; | |
2437 | gimple stmt; | |
2438 | edge_iterator ei; | |
2439 | edge e; | |
2440 | bool ret; | |
2441 | ||
2442 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
2443 | { | |
2444 | stmt = gsi_stmt (gsi); | |
2445 | ||
2446 | if (is_gimple_debug (stmt)) | |
2447 | continue; | |
2448 | ||
2449 | if (gimple_code (stmt) == GIMPLE_LABEL) | |
2450 | { | |
2451 | /* Verify we do not need to preserve the label. */ | |
2452 | if (FORCED_LABEL (gimple_label_label (stmt))) | |
2453 | return false; | |
2454 | ||
2455 | continue; | |
2456 | } | |
2457 | ||
2458 | /* Only handle the case that __builtin_unreachable is the first statement | |
2459 | in the block. We rely on DCE to remove stmts without side-effects | |
2460 | before __builtin_unreachable. */ | |
2461 | if (gsi_stmt (gsi) != gsi_stmt (i)) | |
2462 | return false; | |
2463 | } | |
2464 | ||
2465 | ret = false; | |
2466 | FOR_EACH_EDGE (e, ei, bb->preds) | |
2467 | { | |
2468 | gsi = gsi_last_bb (e->src); | |
522f73a1 | 2469 | if (gsi_end_p (gsi)) |
2470 | continue; | |
f87df69a | 2471 | |
522f73a1 | 2472 | stmt = gsi_stmt (gsi); |
2473 | if (gimple_code (stmt) == GIMPLE_COND) | |
f87df69a | 2474 | { |
2475 | if (e->flags & EDGE_TRUE_VALUE) | |
2476 | gimple_cond_make_false (stmt); | |
2477 | else if (e->flags & EDGE_FALSE_VALUE) | |
2478 | gimple_cond_make_true (stmt); | |
2479 | else | |
2480 | gcc_unreachable (); | |
a03a52b4 | 2481 | update_stmt (stmt); |
f87df69a | 2482 | } |
2483 | else | |
2484 | { | |
2485 | /* Todo: handle other cases, f.i. switch statement. */ | |
2486 | continue; | |
2487 | } | |
2488 | ||
2489 | ret = true; | |
2490 | } | |
2491 | ||
2492 | return ret; | |
2493 | } | |
2494 | ||
4ee9c684 | 2495 | /* A simple pass that attempts to fold all builtin functions. This pass |
2496 | is run after we've propagated as many constants as we can. */ | |
2497 | ||
2a1990e9 | 2498 | static unsigned int |
4ee9c684 | 2499 | execute_fold_all_builtins (void) |
2500 | { | |
b36237eb | 2501 | bool cfg_changed = false; |
4ee9c684 | 2502 | basic_block bb; |
b1b7c0c4 | 2503 | unsigned int todoflags = 0; |
48e1416a | 2504 | |
4ee9c684 | 2505 | FOR_EACH_BB (bb) |
2506 | { | |
75a70cf9 | 2507 | gimple_stmt_iterator i; |
2508 | for (i = gsi_start_bb (bb); !gsi_end_p (i); ) | |
4ee9c684 | 2509 | { |
75a70cf9 | 2510 | gimple stmt, old_stmt; |
4ee9c684 | 2511 | tree callee, result; |
0a39fd54 | 2512 | enum built_in_function fcode; |
4ee9c684 | 2513 | |
75a70cf9 | 2514 | stmt = gsi_stmt (i); |
2515 | ||
2516 | if (gimple_code (stmt) != GIMPLE_CALL) | |
0a39fd54 | 2517 | { |
896a0c42 | 2518 | /* Remove all *ssaname_N ={v} {CLOBBER}; stmts, |
2519 | after the last GIMPLE DSE they aren't needed and might | |
2520 | unnecessarily keep the SSA_NAMEs live. */ | |
2521 | if (gimple_clobber_p (stmt)) | |
2522 | { | |
2523 | tree lhs = gimple_assign_lhs (stmt); | |
2524 | if (TREE_CODE (lhs) == MEM_REF | |
2525 | && TREE_CODE (TREE_OPERAND (lhs, 0)) == SSA_NAME) | |
2526 | { | |
2527 | unlink_stmt_vdef (stmt); | |
2528 | gsi_remove (&i, true); | |
2529 | release_defs (stmt); | |
2530 | continue; | |
2531 | } | |
2532 | } | |
75a70cf9 | 2533 | gsi_next (&i); |
0a39fd54 | 2534 | continue; |
2535 | } | |
75a70cf9 | 2536 | callee = gimple_call_fndecl (stmt); |
4ee9c684 | 2537 | if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) |
0a39fd54 | 2538 | { |
75a70cf9 | 2539 | gsi_next (&i); |
0a39fd54 | 2540 | continue; |
2541 | } | |
2542 | fcode = DECL_FUNCTION_CODE (callee); | |
4ee9c684 | 2543 | |
2d18b16d | 2544 | result = gimple_fold_builtin (stmt); |
5a4b7e1e | 2545 | |
2546 | if (result) | |
75a70cf9 | 2547 | gimple_remove_stmt_histograms (cfun, stmt); |
5a4b7e1e | 2548 | |
4ee9c684 | 2549 | if (!result) |
2550 | switch (DECL_FUNCTION_CODE (callee)) | |
2551 | { | |
2552 | case BUILT_IN_CONSTANT_P: | |
2553 | /* Resolve __builtin_constant_p. If it hasn't been | |
2554 | folded to integer_one_node by now, it's fairly | |
2555 | certain that the value simply isn't constant. */ | |
75a70cf9 | 2556 | result = integer_zero_node; |
4ee9c684 | 2557 | break; |
2558 | ||
fca0886c | 2559 | case BUILT_IN_ASSUME_ALIGNED: |
2560 | /* Remove __builtin_assume_aligned. */ | |
2561 | result = gimple_call_arg (stmt, 0); | |
2562 | break; | |
2563 | ||
bdd0e199 | 2564 | case BUILT_IN_STACK_RESTORE: |
75a70cf9 | 2565 | result = optimize_stack_restore (i); |
8a58ed0a | 2566 | if (result) |
2567 | break; | |
75a70cf9 | 2568 | gsi_next (&i); |
8a58ed0a | 2569 | continue; |
2570 | ||
f87df69a | 2571 | case BUILT_IN_UNREACHABLE: |
2572 | if (optimize_unreachable (i)) | |
2573 | cfg_changed = true; | |
2574 | break; | |
2575 | ||
8a58ed0a | 2576 | case BUILT_IN_VA_START: |
2577 | case BUILT_IN_VA_END: | |
2578 | case BUILT_IN_VA_COPY: | |
2579 | /* These shouldn't be folded before pass_stdarg. */ | |
75a70cf9 | 2580 | result = optimize_stdarg_builtin (stmt); |
bdd0e199 | 2581 | if (result) |
2582 | break; | |
2583 | /* FALLTHRU */ | |
2584 | ||
4ee9c684 | 2585 | default: |
75a70cf9 | 2586 | gsi_next (&i); |
4ee9c684 | 2587 | continue; |
2588 | } | |
2589 | ||
f87df69a | 2590 | if (result == NULL_TREE) |
2591 | break; | |
2592 | ||
4ee9c684 | 2593 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2594 | { | |
2595 | fprintf (dump_file, "Simplified\n "); | |
75a70cf9 | 2596 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
4ee9c684 | 2597 | } |
2598 | ||
75a70cf9 | 2599 | old_stmt = stmt; |
75a70cf9 | 2600 | if (!update_call_from_tree (&i, result)) |
0fefde02 | 2601 | { |
2602 | gimplify_and_update_call_from_tree (&i, result); | |
2603 | todoflags |= TODO_update_address_taken; | |
2604 | } | |
de6ed584 | 2605 | |
75a70cf9 | 2606 | stmt = gsi_stmt (i); |
4c5fd53c | 2607 | update_stmt (stmt); |
de6ed584 | 2608 | |
75a70cf9 | 2609 | if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt) |
2610 | && gimple_purge_dead_eh_edges (bb)) | |
b36237eb | 2611 | cfg_changed = true; |
4ee9c684 | 2612 | |
2613 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2614 | { | |
2615 | fprintf (dump_file, "to\n "); | |
75a70cf9 | 2616 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
4ee9c684 | 2617 | fprintf (dump_file, "\n"); |
2618 | } | |
0a39fd54 | 2619 | |
2620 | /* Retry the same statement if it changed into another | |
2621 | builtin, there might be new opportunities now. */ | |
75a70cf9 | 2622 | if (gimple_code (stmt) != GIMPLE_CALL) |
0a39fd54 | 2623 | { |
75a70cf9 | 2624 | gsi_next (&i); |
0a39fd54 | 2625 | continue; |
2626 | } | |
75a70cf9 | 2627 | callee = gimple_call_fndecl (stmt); |
0a39fd54 | 2628 | if (!callee |
75a70cf9 | 2629 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL |
0a39fd54 | 2630 | || DECL_FUNCTION_CODE (callee) == fcode) |
75a70cf9 | 2631 | gsi_next (&i); |
4ee9c684 | 2632 | } |
2633 | } | |
48e1416a | 2634 | |
b36237eb | 2635 | /* Delete unreachable blocks. */ |
b1b7c0c4 | 2636 | if (cfg_changed) |
2637 | todoflags |= TODO_cleanup_cfg; | |
48e1416a | 2638 | |
b1b7c0c4 | 2639 | return todoflags; |
4ee9c684 | 2640 | } |
2641 | ||
41511585 | 2642 | |
cbe8bda8 | 2643 | namespace { |
2644 | ||
2645 | const pass_data pass_data_fold_builtins = | |
4ee9c684 | 2646 | { |
cbe8bda8 | 2647 | GIMPLE_PASS, /* type */ |
2648 | "fab", /* name */ | |
2649 | OPTGROUP_NONE, /* optinfo_flags */ | |
2650 | false, /* has_gate */ | |
2651 | true, /* has_execute */ | |
2652 | TV_NONE, /* tv_id */ | |
2653 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
2654 | 0, /* properties_provided */ | |
2655 | 0, /* properties_destroyed */ | |
2656 | 0, /* todo_flags_start */ | |
2657 | ( TODO_verify_ssa | TODO_update_ssa ), /* todo_flags_finish */ | |
4ee9c684 | 2658 | }; |
cbe8bda8 | 2659 | |
2660 | class pass_fold_builtins : public gimple_opt_pass | |
2661 | { | |
2662 | public: | |
9af5ce0c | 2663 | pass_fold_builtins (gcc::context *ctxt) |
2664 | : gimple_opt_pass (pass_data_fold_builtins, ctxt) | |
cbe8bda8 | 2665 | {} |
2666 | ||
2667 | /* opt_pass methods: */ | |
ae84f584 | 2668 | opt_pass * clone () { return new pass_fold_builtins (m_ctxt); } |
cbe8bda8 | 2669 | unsigned int execute () { return execute_fold_all_builtins (); } |
2670 | ||
2671 | }; // class pass_fold_builtins | |
2672 | ||
2673 | } // anon namespace | |
2674 | ||
2675 | gimple_opt_pass * | |
2676 | make_pass_fold_builtins (gcc::context *ctxt) | |
2677 | { | |
2678 | return new pass_fold_builtins (ctxt); | |
2679 | } |