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6de9cd9a | 1 | /* Conditional constant propagation pass for the GNU compiler. |
1cdaa211 RG |
2 | Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, |
3 | 2010 Free Software Foundation, Inc. | |
6de9cd9a DN |
4 | Adapted from original RTL SSA-CCP by Daniel Berlin <dberlin@dberlin.org> |
5 | Adapted to GIMPLE trees by Diego Novillo <dnovillo@redhat.com> | |
6 | ||
7 | This file is part of GCC. | |
b8698a0f | 8 | |
6de9cd9a DN |
9 | GCC is free software; you can redistribute it and/or modify it |
10 | under the terms of the GNU General Public License as published by the | |
9dcd6f09 | 11 | Free Software Foundation; either version 3, or (at your option) any |
6de9cd9a | 12 | later version. |
b8698a0f | 13 | |
6de9cd9a DN |
14 | GCC is distributed in the hope that it will be useful, but WITHOUT |
15 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
16 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
17 | for more details. | |
b8698a0f | 18 | |
6de9cd9a | 19 | You should have received a copy of the GNU General Public License |
9dcd6f09 NC |
20 | along with GCC; see the file COPYING3. If not see |
21 | <http://www.gnu.org/licenses/>. */ | |
6de9cd9a | 22 | |
0bca51f0 DN |
23 | /* Conditional constant propagation (CCP) is based on the SSA |
24 | propagation engine (tree-ssa-propagate.c). Constant assignments of | |
25 | the form VAR = CST are propagated from the assignments into uses of | |
26 | VAR, which in turn may generate new constants. The simulation uses | |
27 | a four level lattice to keep track of constant values associated | |
28 | with SSA names. Given an SSA name V_i, it may take one of the | |
29 | following values: | |
30 | ||
106dec71 ZD |
31 | UNINITIALIZED -> the initial state of the value. This value |
32 | is replaced with a correct initial value | |
33 | the first time the value is used, so the | |
34 | rest of the pass does not need to care about | |
35 | it. Using this value simplifies initialization | |
36 | of the pass, and prevents us from needlessly | |
37 | scanning statements that are never reached. | |
0bca51f0 DN |
38 | |
39 | UNDEFINED -> V_i is a local variable whose definition | |
40 | has not been processed yet. Therefore we | |
41 | don't yet know if its value is a constant | |
42 | or not. | |
43 | ||
44 | CONSTANT -> V_i has been found to hold a constant | |
45 | value C. | |
46 | ||
47 | VARYING -> V_i cannot take a constant value, or if it | |
48 | does, it is not possible to determine it | |
49 | at compile time. | |
50 | ||
51 | The core of SSA-CCP is in ccp_visit_stmt and ccp_visit_phi_node: | |
52 | ||
53 | 1- In ccp_visit_stmt, we are interested in assignments whose RHS | |
54 | evaluates into a constant and conditional jumps whose predicate | |
55 | evaluates into a boolean true or false. When an assignment of | |
56 | the form V_i = CONST is found, V_i's lattice value is set to | |
57 | CONSTANT and CONST is associated with it. This causes the | |
58 | propagation engine to add all the SSA edges coming out the | |
59 | assignment into the worklists, so that statements that use V_i | |
60 | can be visited. | |
61 | ||
62 | If the statement is a conditional with a constant predicate, we | |
63 | mark the outgoing edges as executable or not executable | |
64 | depending on the predicate's value. This is then used when | |
65 | visiting PHI nodes to know when a PHI argument can be ignored. | |
b8698a0f | 66 | |
0bca51f0 DN |
67 | |
68 | 2- In ccp_visit_phi_node, if all the PHI arguments evaluate to the | |
69 | same constant C, then the LHS of the PHI is set to C. This | |
70 | evaluation is known as the "meet operation". Since one of the | |
71 | goals of this evaluation is to optimistically return constant | |
72 | values as often as possible, it uses two main short cuts: | |
73 | ||
74 | - If an argument is flowing in through a non-executable edge, it | |
75 | is ignored. This is useful in cases like this: | |
76 | ||
77 | if (PRED) | |
78 | a_9 = 3; | |
79 | else | |
80 | a_10 = 100; | |
81 | a_11 = PHI (a_9, a_10) | |
82 | ||
83 | If PRED is known to always evaluate to false, then we can | |
84 | assume that a_11 will always take its value from a_10, meaning | |
85 | that instead of consider it VARYING (a_9 and a_10 have | |
86 | different values), we can consider it CONSTANT 100. | |
87 | ||
88 | - If an argument has an UNDEFINED value, then it does not affect | |
89 | the outcome of the meet operation. If a variable V_i has an | |
90 | UNDEFINED value, it means that either its defining statement | |
91 | hasn't been visited yet or V_i has no defining statement, in | |
92 | which case the original symbol 'V' is being used | |
93 | uninitialized. Since 'V' is a local variable, the compiler | |
94 | may assume any initial value for it. | |
95 | ||
96 | ||
97 | After propagation, every variable V_i that ends up with a lattice | |
98 | value of CONSTANT will have the associated constant value in the | |
99 | array CONST_VAL[i].VALUE. That is fed into substitute_and_fold for | |
100 | final substitution and folding. | |
101 | ||
6de9cd9a DN |
102 | References: |
103 | ||
104 | Constant propagation with conditional branches, | |
105 | Wegman and Zadeck, ACM TOPLAS 13(2):181-210. | |
106 | ||
107 | Building an Optimizing Compiler, | |
108 | Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9. | |
109 | ||
110 | Advanced Compiler Design and Implementation, | |
111 | Steven Muchnick, Morgan Kaufmann, 1997, Section 12.6 */ | |
112 | ||
113 | #include "config.h" | |
114 | #include "system.h" | |
115 | #include "coretypes.h" | |
116 | #include "tm.h" | |
6de9cd9a | 117 | #include "tree.h" |
750628d8 | 118 | #include "flags.h" |
6de9cd9a | 119 | #include "tm_p.h" |
6de9cd9a | 120 | #include "basic-block.h" |
750628d8 | 121 | #include "output.h" |
750628d8 | 122 | #include "function.h" |
cf835838 JM |
123 | #include "tree-pretty-print.h" |
124 | #include "gimple-pretty-print.h" | |
750628d8 | 125 | #include "timevar.h" |
6de9cd9a | 126 | #include "tree-dump.h" |
750628d8 | 127 | #include "tree-flow.h" |
6de9cd9a | 128 | #include "tree-pass.h" |
750628d8 | 129 | #include "tree-ssa-propagate.h" |
53a8f709 | 130 | #include "value-prof.h" |
750628d8 | 131 | #include "langhooks.h" |
ae3df618 | 132 | #include "target.h" |
718f9c0f | 133 | #include "diagnostic-core.h" |
6ac01510 | 134 | #include "toplev.h" |
74fe548b | 135 | #include "dbgcnt.h" |
6de9cd9a DN |
136 | |
137 | ||
138 | /* Possible lattice values. */ | |
139 | typedef enum | |
140 | { | |
106dec71 | 141 | UNINITIALIZED, |
6de9cd9a DN |
142 | UNDEFINED, |
143 | CONSTANT, | |
144 | VARYING | |
0bca51f0 | 145 | } ccp_lattice_t; |
6de9cd9a | 146 | |
455e6d5b RG |
147 | struct prop_value_d { |
148 | /* Lattice value. */ | |
149 | ccp_lattice_t lattice_val; | |
150 | ||
151 | /* Propagated value. */ | |
152 | tree value; | |
0b4b14ac RG |
153 | |
154 | /* Mask that applies to the propagated value during CCP. For | |
155 | X with a CONSTANT lattice value X & ~mask == value & ~mask. */ | |
156 | double_int mask; | |
455e6d5b RG |
157 | }; |
158 | ||
159 | typedef struct prop_value_d prop_value_t; | |
160 | ||
0bca51f0 DN |
161 | /* Array of propagated constant values. After propagation, |
162 | CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If | |
163 | the constant is held in an SSA name representing a memory store | |
38635499 DN |
164 | (i.e., a VDEF), CONST_VAL[I].MEM_REF will contain the actual |
165 | memory reference used to store (i.e., the LHS of the assignment | |
166 | doing the store). */ | |
404f4351 | 167 | static prop_value_t *const_val; |
6de9cd9a | 168 | |
25e20805 | 169 | static void canonicalize_float_value (prop_value_t *); |
f61e18ec | 170 | static bool ccp_fold_stmt (gimple_stmt_iterator *); |
697c3575 JH |
171 | static tree fold_ctor_reference (tree type, tree ctor, |
172 | unsigned HOST_WIDE_INT offset, | |
173 | unsigned HOST_WIDE_INT size); | |
25e20805 | 174 | |
0bca51f0 | 175 | /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */ |
95eec0d6 DB |
176 | |
177 | static void | |
0bca51f0 | 178 | dump_lattice_value (FILE *outf, const char *prefix, prop_value_t val) |
95eec0d6 | 179 | { |
750628d8 | 180 | switch (val.lattice_val) |
95eec0d6 | 181 | { |
0bca51f0 DN |
182 | case UNINITIALIZED: |
183 | fprintf (outf, "%sUNINITIALIZED", prefix); | |
184 | break; | |
750628d8 DN |
185 | case UNDEFINED: |
186 | fprintf (outf, "%sUNDEFINED", prefix); | |
187 | break; | |
188 | case VARYING: | |
189 | fprintf (outf, "%sVARYING", prefix); | |
190 | break; | |
750628d8 DN |
191 | case CONSTANT: |
192 | fprintf (outf, "%sCONSTANT ", prefix); | |
0b4b14ac RG |
193 | if (TREE_CODE (val.value) != INTEGER_CST |
194 | || double_int_zero_p (val.mask)) | |
195 | print_generic_expr (outf, val.value, dump_flags); | |
196 | else | |
197 | { | |
198 | double_int cval = double_int_and_not (tree_to_double_int (val.value), | |
199 | val.mask); | |
200 | fprintf (outf, "%sCONSTANT " HOST_WIDE_INT_PRINT_DOUBLE_HEX, | |
201 | prefix, cval.high, cval.low); | |
202 | fprintf (outf, " (" HOST_WIDE_INT_PRINT_DOUBLE_HEX ")", | |
203 | val.mask.high, val.mask.low); | |
204 | } | |
750628d8 DN |
205 | break; |
206 | default: | |
1e128c5f | 207 | gcc_unreachable (); |
750628d8 | 208 | } |
95eec0d6 | 209 | } |
6de9cd9a | 210 | |
6de9cd9a | 211 | |
0bca51f0 DN |
212 | /* Print lattice value VAL to stderr. */ |
213 | ||
214 | void debug_lattice_value (prop_value_t val); | |
215 | ||
24e47c76 | 216 | DEBUG_FUNCTION void |
0bca51f0 DN |
217 | debug_lattice_value (prop_value_t val) |
218 | { | |
219 | dump_lattice_value (stderr, "", val); | |
220 | fprintf (stderr, "\n"); | |
221 | } | |
6de9cd9a | 222 | |
6de9cd9a | 223 | |
0bca51f0 DN |
224 | /* Compute a default value for variable VAR and store it in the |
225 | CONST_VAL array. The following rules are used to get default | |
226 | values: | |
95eec0d6 | 227 | |
0bca51f0 DN |
228 | 1- Global and static variables that are declared constant are |
229 | considered CONSTANT. | |
230 | ||
231 | 2- Any other value is considered UNDEFINED. This is useful when | |
750628d8 DN |
232 | considering PHI nodes. PHI arguments that are undefined do not |
233 | change the constant value of the PHI node, which allows for more | |
0bca51f0 | 234 | constants to be propagated. |
6de9cd9a | 235 | |
caf55296 | 236 | 3- Variables defined by statements other than assignments and PHI |
0bca51f0 | 237 | nodes are considered VARYING. |
6de9cd9a | 238 | |
caf55296 | 239 | 4- Initial values of variables that are not GIMPLE registers are |
106dec71 | 240 | considered VARYING. */ |
6de9cd9a | 241 | |
0bca51f0 DN |
242 | static prop_value_t |
243 | get_default_value (tree var) | |
244 | { | |
245 | tree sym = SSA_NAME_VAR (var); | |
0b4b14ac | 246 | prop_value_t val = { UNINITIALIZED, NULL_TREE, { 0, 0 } }; |
e8114fba RG |
247 | gimple stmt; |
248 | ||
249 | stmt = SSA_NAME_DEF_STMT (var); | |
250 | ||
251 | if (gimple_nop_p (stmt)) | |
6de9cd9a | 252 | { |
e8114fba RG |
253 | /* Variables defined by an empty statement are those used |
254 | before being initialized. If VAR is a local variable, we | |
255 | can assume initially that it is UNDEFINED, otherwise we must | |
256 | consider it VARYING. */ | |
6938f93f JH |
257 | if (is_gimple_reg (sym) |
258 | && TREE_CODE (sym) == VAR_DECL) | |
e8114fba RG |
259 | val.lattice_val = UNDEFINED; |
260 | else | |
0b4b14ac RG |
261 | { |
262 | val.lattice_val = VARYING; | |
263 | val.mask = double_int_minus_one; | |
264 | } | |
6de9cd9a | 265 | } |
e8114fba RG |
266 | else if (is_gimple_assign (stmt) |
267 | /* Value-returning GIMPLE_CALL statements assign to | |
268 | a variable, and are treated similarly to GIMPLE_ASSIGN. */ | |
269 | || (is_gimple_call (stmt) | |
270 | && gimple_call_lhs (stmt) != NULL_TREE) | |
271 | || gimple_code (stmt) == GIMPLE_PHI) | |
750628d8 | 272 | { |
e8114fba RG |
273 | tree cst; |
274 | if (gimple_assign_single_p (stmt) | |
275 | && DECL_P (gimple_assign_rhs1 (stmt)) | |
276 | && (cst = get_symbol_constant_value (gimple_assign_rhs1 (stmt)))) | |
0bca51f0 | 277 | { |
e8114fba RG |
278 | val.lattice_val = CONSTANT; |
279 | val.value = cst; | |
0bca51f0 DN |
280 | } |
281 | else | |
e8114fba RG |
282 | /* Any other variable defined by an assignment or a PHI node |
283 | is considered UNDEFINED. */ | |
284 | val.lattice_val = UNDEFINED; | |
285 | } | |
286 | else | |
287 | { | |
288 | /* Otherwise, VAR will never take on a constant value. */ | |
289 | val.lattice_val = VARYING; | |
0b4b14ac | 290 | val.mask = double_int_minus_one; |
750628d8 | 291 | } |
6de9cd9a | 292 | |
750628d8 DN |
293 | return val; |
294 | } | |
6de9cd9a | 295 | |
6de9cd9a | 296 | |
106dec71 | 297 | /* Get the constant value associated with variable VAR. */ |
6de9cd9a | 298 | |
106dec71 ZD |
299 | static inline prop_value_t * |
300 | get_value (tree var) | |
0bca51f0 | 301 | { |
ed97ddc6 | 302 | prop_value_t *val; |
106dec71 | 303 | |
ed97ddc6 RG |
304 | if (const_val == NULL) |
305 | return NULL; | |
306 | ||
307 | val = &const_val[SSA_NAME_VERSION (var)]; | |
106dec71 | 308 | if (val->lattice_val == UNINITIALIZED) |
6de9cd9a DN |
309 | *val = get_default_value (var); |
310 | ||
25e20805 RG |
311 | canonicalize_float_value (val); |
312 | ||
6de9cd9a DN |
313 | return val; |
314 | } | |
315 | ||
84d77ca6 RG |
316 | /* Return the constant tree value associated with VAR. */ |
317 | ||
318 | static inline tree | |
319 | get_constant_value (tree var) | |
320 | { | |
e196b221 JH |
321 | prop_value_t *val; |
322 | if (TREE_CODE (var) != SSA_NAME) | |
323 | { | |
324 | if (is_gimple_min_invariant (var)) | |
325 | return var; | |
326 | return NULL_TREE; | |
327 | } | |
328 | val = get_value (var); | |
0b4b14ac RG |
329 | if (val |
330 | && val->lattice_val == CONSTANT | |
331 | && (TREE_CODE (val->value) != INTEGER_CST | |
332 | || double_int_zero_p (val->mask))) | |
84d77ca6 RG |
333 | return val->value; |
334 | return NULL_TREE; | |
335 | } | |
336 | ||
106dec71 ZD |
337 | /* Sets the value associated with VAR to VARYING. */ |
338 | ||
339 | static inline void | |
340 | set_value_varying (tree var) | |
341 | { | |
342 | prop_value_t *val = &const_val[SSA_NAME_VERSION (var)]; | |
343 | ||
344 | val->lattice_val = VARYING; | |
345 | val->value = NULL_TREE; | |
0b4b14ac | 346 | val->mask = double_int_minus_one; |
106dec71 | 347 | } |
6de9cd9a | 348 | |
fbb5445b L |
349 | /* For float types, modify the value of VAL to make ccp work correctly |
350 | for non-standard values (-0, NaN): | |
351 | ||
352 | If HONOR_SIGNED_ZEROS is false, and VAL = -0, we canonicalize it to 0. | |
353 | If HONOR_NANS is false, and VAL is NaN, we canonicalize it to UNDEFINED. | |
354 | This is to fix the following problem (see PR 29921): Suppose we have | |
355 | ||
356 | x = 0.0 * y | |
357 | ||
358 | and we set value of y to NaN. This causes value of x to be set to NaN. | |
359 | When we later determine that y is in fact VARYING, fold uses the fact | |
360 | that HONOR_NANS is false, and we try to change the value of x to 0, | |
361 | causing an ICE. With HONOR_NANS being false, the real appearance of | |
362 | NaN would cause undefined behavior, though, so claiming that y (and x) | |
363 | are UNDEFINED initially is correct. */ | |
364 | ||
365 | static void | |
366 | canonicalize_float_value (prop_value_t *val) | |
367 | { | |
368 | enum machine_mode mode; | |
369 | tree type; | |
370 | REAL_VALUE_TYPE d; | |
371 | ||
372 | if (val->lattice_val != CONSTANT | |
373 | || TREE_CODE (val->value) != REAL_CST) | |
374 | return; | |
375 | ||
376 | d = TREE_REAL_CST (val->value); | |
377 | type = TREE_TYPE (val->value); | |
378 | mode = TYPE_MODE (type); | |
379 | ||
380 | if (!HONOR_SIGNED_ZEROS (mode) | |
381 | && REAL_VALUE_MINUS_ZERO (d)) | |
382 | { | |
383 | val->value = build_real (type, dconst0); | |
384 | return; | |
385 | } | |
386 | ||
387 | if (!HONOR_NANS (mode) | |
388 | && REAL_VALUE_ISNAN (d)) | |
389 | { | |
390 | val->lattice_val = UNDEFINED; | |
391 | val->value = NULL; | |
fbb5445b L |
392 | return; |
393 | } | |
394 | } | |
395 | ||
0b4b14ac RG |
396 | /* Return whether the lattice transition is valid. */ |
397 | ||
398 | static bool | |
399 | valid_lattice_transition (prop_value_t old_val, prop_value_t new_val) | |
400 | { | |
401 | /* Lattice transitions must always be monotonically increasing in | |
402 | value. */ | |
403 | if (old_val.lattice_val < new_val.lattice_val) | |
404 | return true; | |
405 | ||
406 | if (old_val.lattice_val != new_val.lattice_val) | |
407 | return false; | |
408 | ||
409 | if (!old_val.value && !new_val.value) | |
410 | return true; | |
411 | ||
412 | /* Now both lattice values are CONSTANT. */ | |
413 | ||
414 | /* Allow transitioning from &x to &x & ~3. */ | |
415 | if (TREE_CODE (old_val.value) != INTEGER_CST | |
416 | && TREE_CODE (new_val.value) == INTEGER_CST) | |
417 | return true; | |
418 | ||
419 | /* Bit-lattices have to agree in the still valid bits. */ | |
420 | if (TREE_CODE (old_val.value) == INTEGER_CST | |
421 | && TREE_CODE (new_val.value) == INTEGER_CST) | |
422 | return double_int_equal_p | |
423 | (double_int_and_not (tree_to_double_int (old_val.value), | |
424 | new_val.mask), | |
425 | double_int_and_not (tree_to_double_int (new_val.value), | |
426 | new_val.mask)); | |
427 | ||
428 | /* Otherwise constant values have to agree. */ | |
429 | return operand_equal_p (old_val.value, new_val.value, 0); | |
430 | } | |
431 | ||
0bca51f0 DN |
432 | /* Set the value for variable VAR to NEW_VAL. Return true if the new |
433 | value is different from VAR's previous value. */ | |
6de9cd9a | 434 | |
750628d8 | 435 | static bool |
0bca51f0 | 436 | set_lattice_value (tree var, prop_value_t new_val) |
6de9cd9a | 437 | { |
7a95d078 RG |
438 | /* We can deal with old UNINITIALIZED values just fine here. */ |
439 | prop_value_t *old_val = &const_val[SSA_NAME_VERSION (var)]; | |
0bca51f0 | 440 | |
fbb5445b L |
441 | canonicalize_float_value (&new_val); |
442 | ||
0b4b14ac RG |
443 | /* We have to be careful to not go up the bitwise lattice |
444 | represented by the mask. | |
445 | ??? This doesn't seem to be the best place to enforce this. */ | |
446 | if (new_val.lattice_val == CONSTANT | |
447 | && old_val->lattice_val == CONSTANT | |
448 | && TREE_CODE (new_val.value) == INTEGER_CST | |
449 | && TREE_CODE (old_val->value) == INTEGER_CST) | |
450 | { | |
451 | double_int diff; | |
452 | diff = double_int_xor (tree_to_double_int (new_val.value), | |
453 | tree_to_double_int (old_val->value)); | |
454 | new_val.mask = double_int_ior (new_val.mask, | |
455 | double_int_ior (old_val->mask, diff)); | |
456 | } | |
106dec71 | 457 | |
0b4b14ac | 458 | gcc_assert (valid_lattice_transition (*old_val, new_val)); |
0bca51f0 | 459 | |
0b4b14ac RG |
460 | /* If *OLD_VAL and NEW_VAL are the same, return false to inform the |
461 | caller that this was a non-transition. */ | |
462 | if (old_val->lattice_val != new_val.lattice_val | |
463 | || (new_val.lattice_val == CONSTANT | |
464 | && TREE_CODE (new_val.value) == INTEGER_CST | |
465 | && (TREE_CODE (old_val->value) != INTEGER_CST | |
466 | || !double_int_equal_p (new_val.mask, old_val->mask)))) | |
6de9cd9a | 467 | { |
0b4b14ac RG |
468 | /* ??? We would like to delay creation of INTEGER_CSTs from |
469 | partially constants here. */ | |
470 | ||
750628d8 DN |
471 | if (dump_file && (dump_flags & TDF_DETAILS)) |
472 | { | |
0bca51f0 | 473 | dump_lattice_value (dump_file, "Lattice value changed to ", new_val); |
106dec71 | 474 | fprintf (dump_file, ". Adding SSA edges to worklist.\n"); |
750628d8 DN |
475 | } |
476 | ||
0bca51f0 DN |
477 | *old_val = new_val; |
478 | ||
7a95d078 | 479 | gcc_assert (new_val.lattice_val != UNINITIALIZED); |
106dec71 | 480 | return true; |
6de9cd9a | 481 | } |
750628d8 DN |
482 | |
483 | return false; | |
6de9cd9a DN |
484 | } |
485 | ||
0b4b14ac RG |
486 | static prop_value_t get_value_for_expr (tree, bool); |
487 | static prop_value_t bit_value_binop (enum tree_code, tree, tree, tree); | |
488 | static void bit_value_binop_1 (enum tree_code, tree, double_int *, double_int *, | |
489 | tree, double_int, double_int, | |
490 | tree, double_int, double_int); | |
491 | ||
492 | /* Return a double_int that can be used for bitwise simplifications | |
493 | from VAL. */ | |
494 | ||
495 | static double_int | |
496 | value_to_double_int (prop_value_t val) | |
497 | { | |
498 | if (val.value | |
499 | && TREE_CODE (val.value) == INTEGER_CST) | |
500 | return tree_to_double_int (val.value); | |
501 | else | |
502 | return double_int_zero; | |
503 | } | |
504 | ||
505 | /* Return the value for the address expression EXPR based on alignment | |
506 | information. */ | |
7a95d078 RG |
507 | |
508 | static prop_value_t | |
0b4b14ac RG |
509 | get_value_from_alignment (tree expr) |
510 | { | |
511 | prop_value_t val; | |
512 | HOST_WIDE_INT bitsize, bitpos; | |
513 | tree base, offset; | |
514 | enum machine_mode mode; | |
515 | int align; | |
516 | ||
517 | gcc_assert (TREE_CODE (expr) == ADDR_EXPR); | |
518 | ||
519 | base = get_inner_reference (TREE_OPERAND (expr, 0), | |
520 | &bitsize, &bitpos, &offset, | |
521 | &mode, &align, &align, false); | |
be1ac4ec | 522 | if (TREE_CODE (base) == MEM_REF) |
0b4b14ac RG |
523 | val = bit_value_binop (PLUS_EXPR, TREE_TYPE (expr), |
524 | TREE_OPERAND (base, 0), TREE_OPERAND (base, 1)); | |
525 | else if (base | |
e80c2726 | 526 | && ((align = get_object_alignment (base, BIGGEST_ALIGNMENT)) |
0b4b14ac RG |
527 | > BITS_PER_UNIT)) |
528 | { | |
529 | val.lattice_val = CONSTANT; | |
530 | /* We assume pointers are zero-extended. */ | |
531 | val.mask = double_int_and_not | |
532 | (double_int_mask (TYPE_PRECISION (TREE_TYPE (expr))), | |
533 | uhwi_to_double_int (align / BITS_PER_UNIT - 1)); | |
534 | val.value = build_int_cst (TREE_TYPE (expr), 0); | |
535 | } | |
536 | else | |
537 | { | |
538 | val.lattice_val = VARYING; | |
539 | val.mask = double_int_minus_one; | |
540 | val.value = NULL_TREE; | |
541 | } | |
542 | if (bitpos != 0) | |
543 | { | |
544 | double_int value, mask; | |
545 | bit_value_binop_1 (PLUS_EXPR, TREE_TYPE (expr), &value, &mask, | |
546 | TREE_TYPE (expr), value_to_double_int (val), val.mask, | |
547 | TREE_TYPE (expr), | |
548 | shwi_to_double_int (bitpos / BITS_PER_UNIT), | |
549 | double_int_zero); | |
550 | val.lattice_val = double_int_minus_one_p (mask) ? VARYING : CONSTANT; | |
551 | val.mask = mask; | |
552 | if (val.lattice_val == CONSTANT) | |
553 | val.value = double_int_to_tree (TREE_TYPE (expr), value); | |
554 | else | |
555 | val.value = NULL_TREE; | |
556 | } | |
557 | /* ??? We should handle i * 4 and more complex expressions from | |
558 | the offset, possibly by just expanding get_value_for_expr. */ | |
559 | if (offset != NULL_TREE) | |
560 | { | |
561 | double_int value, mask; | |
562 | prop_value_t oval = get_value_for_expr (offset, true); | |
563 | bit_value_binop_1 (PLUS_EXPR, TREE_TYPE (expr), &value, &mask, | |
564 | TREE_TYPE (expr), value_to_double_int (val), val.mask, | |
565 | TREE_TYPE (expr), value_to_double_int (oval), | |
566 | oval.mask); | |
567 | val.mask = mask; | |
568 | if (double_int_minus_one_p (mask)) | |
569 | { | |
570 | val.lattice_val = VARYING; | |
571 | val.value = NULL_TREE; | |
572 | } | |
573 | else | |
574 | { | |
575 | val.lattice_val = CONSTANT; | |
576 | val.value = double_int_to_tree (TREE_TYPE (expr), value); | |
577 | } | |
578 | } | |
579 | ||
580 | return val; | |
581 | } | |
582 | ||
583 | /* Return the value for the tree operand EXPR. If FOR_BITS_P is true | |
584 | return constant bits extracted from alignment information for | |
585 | invariant addresses. */ | |
586 | ||
587 | static prop_value_t | |
588 | get_value_for_expr (tree expr, bool for_bits_p) | |
7a95d078 RG |
589 | { |
590 | prop_value_t val; | |
591 | ||
592 | if (TREE_CODE (expr) == SSA_NAME) | |
0b4b14ac RG |
593 | { |
594 | val = *get_value (expr); | |
595 | if (for_bits_p | |
596 | && val.lattice_val == CONSTANT | |
597 | && TREE_CODE (val.value) == ADDR_EXPR) | |
598 | val = get_value_from_alignment (val.value); | |
599 | } | |
600 | else if (is_gimple_min_invariant (expr) | |
601 | && (!for_bits_p || TREE_CODE (expr) != ADDR_EXPR)) | |
7a95d078 RG |
602 | { |
603 | val.lattice_val = CONSTANT; | |
604 | val.value = expr; | |
0b4b14ac | 605 | val.mask = double_int_zero; |
7a95d078 RG |
606 | canonicalize_float_value (&val); |
607 | } | |
0b4b14ac RG |
608 | else if (TREE_CODE (expr) == ADDR_EXPR) |
609 | val = get_value_from_alignment (expr); | |
7a95d078 RG |
610 | else |
611 | { | |
612 | val.lattice_val = VARYING; | |
0b4b14ac | 613 | val.mask = double_int_minus_one; |
7a95d078 RG |
614 | val.value = NULL_TREE; |
615 | } | |
7a95d078 RG |
616 | return val; |
617 | } | |
618 | ||
0bca51f0 | 619 | /* Return the likely CCP lattice value for STMT. |
6de9cd9a | 620 | |
750628d8 | 621 | If STMT has no operands, then return CONSTANT. |
6de9cd9a | 622 | |
7f879c96 RG |
623 | Else if undefinedness of operands of STMT cause its value to be |
624 | undefined, then return UNDEFINED. | |
6de9cd9a | 625 | |
750628d8 | 626 | Else if any operands of STMT are constants, then return CONSTANT. |
6de9cd9a | 627 | |
750628d8 | 628 | Else return VARYING. */ |
6de9cd9a | 629 | |
0bca51f0 | 630 | static ccp_lattice_t |
726a989a | 631 | likely_value (gimple stmt) |
750628d8 | 632 | { |
7f879c96 | 633 | bool has_constant_operand, has_undefined_operand, all_undefined_operands; |
750628d8 DN |
634 | tree use; |
635 | ssa_op_iter iter; | |
e8114fba | 636 | unsigned i; |
6de9cd9a | 637 | |
e0c68ce9 | 638 | enum gimple_code code = gimple_code (stmt); |
726a989a RB |
639 | |
640 | /* This function appears to be called only for assignments, calls, | |
641 | conditionals, and switches, due to the logic in visit_stmt. */ | |
642 | gcc_assert (code == GIMPLE_ASSIGN | |
643 | || code == GIMPLE_CALL | |
644 | || code == GIMPLE_COND | |
645 | || code == GIMPLE_SWITCH); | |
0bca51f0 DN |
646 | |
647 | /* If the statement has volatile operands, it won't fold to a | |
648 | constant value. */ | |
726a989a | 649 | if (gimple_has_volatile_ops (stmt)) |
0bca51f0 DN |
650 | return VARYING; |
651 | ||
726a989a | 652 | /* Arrive here for more complex cases. */ |
106dec71 | 653 | has_constant_operand = false; |
7f879c96 RG |
654 | has_undefined_operand = false; |
655 | all_undefined_operands = true; | |
e8114fba | 656 | FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE) |
750628d8 | 657 | { |
106dec71 | 658 | prop_value_t *val = get_value (use); |
750628d8 | 659 | |
106dec71 | 660 | if (val->lattice_val == UNDEFINED) |
7f879c96 RG |
661 | has_undefined_operand = true; |
662 | else | |
663 | all_undefined_operands = false; | |
0bca51f0 | 664 | |
750628d8 | 665 | if (val->lattice_val == CONSTANT) |
106dec71 | 666 | has_constant_operand = true; |
6de9cd9a | 667 | } |
750628d8 | 668 | |
5006671f RG |
669 | /* There may be constants in regular rhs operands. For calls we |
670 | have to ignore lhs, fndecl and static chain, otherwise only | |
671 | the lhs. */ | |
672 | for (i = (is_gimple_call (stmt) ? 2 : 0) + gimple_has_lhs (stmt); | |
e8114fba RG |
673 | i < gimple_num_ops (stmt); ++i) |
674 | { | |
675 | tree op = gimple_op (stmt, i); | |
676 | if (!op || TREE_CODE (op) == SSA_NAME) | |
677 | continue; | |
678 | if (is_gimple_min_invariant (op)) | |
679 | has_constant_operand = true; | |
680 | } | |
681 | ||
1cdaa211 RG |
682 | if (has_constant_operand) |
683 | all_undefined_operands = false; | |
684 | ||
7f879c96 RG |
685 | /* If the operation combines operands like COMPLEX_EXPR make sure to |
686 | not mark the result UNDEFINED if only one part of the result is | |
687 | undefined. */ | |
726a989a | 688 | if (has_undefined_operand && all_undefined_operands) |
7f879c96 | 689 | return UNDEFINED; |
726a989a | 690 | else if (code == GIMPLE_ASSIGN && has_undefined_operand) |
7f879c96 | 691 | { |
726a989a | 692 | switch (gimple_assign_rhs_code (stmt)) |
7f879c96 RG |
693 | { |
694 | /* Unary operators are handled with all_undefined_operands. */ | |
695 | case PLUS_EXPR: | |
696 | case MINUS_EXPR: | |
7f879c96 | 697 | case POINTER_PLUS_EXPR: |
7f879c96 RG |
698 | /* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected. |
699 | Not bitwise operators, one VARYING operand may specify the | |
700 | result completely. Not logical operators for the same reason. | |
0cedb9e9 RG |
701 | Not COMPLEX_EXPR as one VARYING operand makes the result partly |
702 | not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because | |
703 | the undefined operand may be promoted. */ | |
7f879c96 RG |
704 | return UNDEFINED; |
705 | ||
706 | default: | |
707 | ; | |
708 | } | |
709 | } | |
710 | /* If there was an UNDEFINED operand but the result may be not UNDEFINED | |
711 | fall back to VARYING even if there were CONSTANT operands. */ | |
712 | if (has_undefined_operand) | |
713 | return VARYING; | |
714 | ||
e8114fba RG |
715 | /* We do not consider virtual operands here -- load from read-only |
716 | memory may have only VARYING virtual operands, but still be | |
717 | constant. */ | |
106dec71 | 718 | if (has_constant_operand |
e8114fba | 719 | || gimple_references_memory_p (stmt)) |
0bca51f0 DN |
720 | return CONSTANT; |
721 | ||
106dec71 | 722 | return VARYING; |
6de9cd9a DN |
723 | } |
724 | ||
106dec71 ZD |
725 | /* Returns true if STMT cannot be constant. */ |
726 | ||
727 | static bool | |
726a989a | 728 | surely_varying_stmt_p (gimple stmt) |
106dec71 ZD |
729 | { |
730 | /* If the statement has operands that we cannot handle, it cannot be | |
731 | constant. */ | |
726a989a | 732 | if (gimple_has_volatile_ops (stmt)) |
106dec71 ZD |
733 | return true; |
734 | ||
174ef36d RG |
735 | /* If it is a call and does not return a value or is not a |
736 | builtin and not an indirect call, it is varying. */ | |
726a989a | 737 | if (is_gimple_call (stmt)) |
174ef36d RG |
738 | { |
739 | tree fndecl; | |
740 | if (!gimple_call_lhs (stmt) | |
741 | || ((fndecl = gimple_call_fndecl (stmt)) != NULL_TREE | |
99f536cc | 742 | && !DECL_BUILT_IN (fndecl))) |
174ef36d RG |
743 | return true; |
744 | } | |
106dec71 | 745 | |
e8114fba | 746 | /* Any other store operation is not interesting. */ |
5006671f | 747 | else if (gimple_vdef (stmt)) |
e8114fba RG |
748 | return true; |
749 | ||
106dec71 ZD |
750 | /* Anything other than assignments and conditional jumps are not |
751 | interesting for CCP. */ | |
726a989a | 752 | if (gimple_code (stmt) != GIMPLE_ASSIGN |
174ef36d RG |
753 | && gimple_code (stmt) != GIMPLE_COND |
754 | && gimple_code (stmt) != GIMPLE_SWITCH | |
755 | && gimple_code (stmt) != GIMPLE_CALL) | |
106dec71 ZD |
756 | return true; |
757 | ||
758 | return false; | |
759 | } | |
6de9cd9a | 760 | |
750628d8 | 761 | /* Initialize local data structures for CCP. */ |
6de9cd9a DN |
762 | |
763 | static void | |
750628d8 | 764 | ccp_initialize (void) |
6de9cd9a | 765 | { |
750628d8 | 766 | basic_block bb; |
6de9cd9a | 767 | |
b9eae1a9 | 768 | const_val = XCNEWVEC (prop_value_t, num_ssa_names); |
6de9cd9a | 769 | |
750628d8 DN |
770 | /* Initialize simulation flags for PHI nodes and statements. */ |
771 | FOR_EACH_BB (bb) | |
6de9cd9a | 772 | { |
726a989a | 773 | gimple_stmt_iterator i; |
6de9cd9a | 774 | |
726a989a | 775 | for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) |
750628d8 | 776 | { |
726a989a | 777 | gimple stmt = gsi_stmt (i); |
cd6ea7a2 RH |
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); | |
6de9cd9a | 787 | |
106dec71 | 788 | if (is_varying) |
750628d8 | 789 | { |
0bca51f0 DN |
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) | |
e8114fba | 796 | set_value_varying (def); |
750628d8 | 797 | } |
726a989a | 798 | prop_set_simulate_again (stmt, !is_varying); |
750628d8 | 799 | } |
6de9cd9a DN |
800 | } |
801 | ||
726a989a RB |
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. */ | |
750628d8 | 805 | FOR_EACH_BB (bb) |
6de9cd9a | 806 | { |
726a989a | 807 | gimple_stmt_iterator i; |
750628d8 | 808 | |
726a989a RB |
809 | for (i = gsi_start_phis (bb); !gsi_end_p (i); gsi_next (&i)) |
810 | { | |
811 | gimple phi = gsi_stmt (i); | |
812 | ||
dce2b2f6 | 813 | if (!is_gimple_reg (gimple_phi_result (phi))) |
726a989a | 814 | prop_set_simulate_again (phi, false); |
106dec71 | 815 | else |
726a989a | 816 | prop_set_simulate_again (phi, true); |
750628d8 | 817 | } |
6de9cd9a | 818 | } |
750628d8 | 819 | } |
6de9cd9a | 820 | |
74fe548b XDL |
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; | |
0b4b14ac | 834 | const_val[i].mask = double_int_minus_one; |
74fe548b XDL |
835 | const_val[i].value = NULL_TREE; |
836 | } | |
837 | } | |
838 | } | |
839 | ||
6de9cd9a | 840 | |
0bca51f0 | 841 | /* Do final substitution of propagated values, cleanup the flowgraph and |
b8698a0f | 842 | free allocated storage. |
6de9cd9a | 843 | |
3253eafb JH |
844 | Return TRUE when something was optimized. */ |
845 | ||
846 | static bool | |
0bca51f0 | 847 | ccp_finalize (void) |
6de9cd9a | 848 | { |
74fe548b | 849 | bool something_changed; |
1be38ccb | 850 | unsigned i; |
74fe548b XDL |
851 | |
852 | do_dbg_cnt (); | |
1be38ccb RG |
853 | |
854 | /* Derive alignment and misalignment information from partially | |
855 | constant pointers in the lattice. */ | |
856 | for (i = 1; i < num_ssa_names; ++i) | |
857 | { | |
858 | tree name = ssa_name (i); | |
859 | prop_value_t *val; | |
860 | struct ptr_info_def *pi; | |
861 | unsigned int tem, align; | |
862 | ||
863 | if (!name | |
864 | || !POINTER_TYPE_P (TREE_TYPE (name))) | |
865 | continue; | |
866 | ||
867 | val = get_value (name); | |
868 | if (val->lattice_val != CONSTANT | |
869 | || TREE_CODE (val->value) != INTEGER_CST) | |
870 | continue; | |
871 | ||
872 | /* Trailing constant bits specify the alignment, trailing value | |
873 | bits the misalignment. */ | |
874 | tem = val->mask.low; | |
875 | align = (tem & -tem); | |
876 | if (align == 1) | |
877 | continue; | |
878 | ||
879 | pi = get_ptr_info (name); | |
880 | pi->align = align; | |
881 | pi->misalign = TREE_INT_CST_LOW (val->value) & (align - 1); | |
882 | } | |
883 | ||
0bca51f0 | 884 | /* Perform substitutions based on the known constant values. */ |
455e6d5b RG |
885 | something_changed = substitute_and_fold (get_constant_value, |
886 | ccp_fold_stmt, true); | |
6de9cd9a | 887 | |
0bca51f0 | 888 | free (const_val); |
ed97ddc6 | 889 | const_val = NULL; |
3253eafb | 890 | return something_changed;; |
6de9cd9a DN |
891 | } |
892 | ||
893 | ||
0bca51f0 DN |
894 | /* Compute the meet operator between *VAL1 and *VAL2. Store the result |
895 | in VAL1. | |
896 | ||
897 | any M UNDEFINED = any | |
0bca51f0 DN |
898 | any M VARYING = VARYING |
899 | Ci M Cj = Ci if (i == j) | |
900 | Ci M Cj = VARYING if (i != j) | |
106dec71 | 901 | */ |
6de9cd9a DN |
902 | |
903 | static void | |
0bca51f0 | 904 | ccp_lattice_meet (prop_value_t *val1, prop_value_t *val2) |
6de9cd9a | 905 | { |
0bca51f0 | 906 | if (val1->lattice_val == UNDEFINED) |
6de9cd9a | 907 | { |
0bca51f0 DN |
908 | /* UNDEFINED M any = any */ |
909 | *val1 = *val2; | |
750628d8 | 910 | } |
0bca51f0 | 911 | else if (val2->lattice_val == UNDEFINED) |
195da47b | 912 | { |
0bca51f0 DN |
913 | /* any M UNDEFINED = any |
914 | Nothing to do. VAL1 already contains the value we want. */ | |
915 | ; | |
195da47b | 916 | } |
0bca51f0 DN |
917 | else if (val1->lattice_val == VARYING |
918 | || val2->lattice_val == VARYING) | |
750628d8 | 919 | { |
0bca51f0 DN |
920 | /* any M VARYING = VARYING. */ |
921 | val1->lattice_val = VARYING; | |
0b4b14ac | 922 | val1->mask = double_int_minus_one; |
0bca51f0 | 923 | val1->value = NULL_TREE; |
750628d8 | 924 | } |
0b4b14ac RG |
925 | else if (val1->lattice_val == CONSTANT |
926 | && val2->lattice_val == CONSTANT | |
927 | && TREE_CODE (val1->value) == INTEGER_CST | |
928 | && TREE_CODE (val2->value) == INTEGER_CST) | |
929 | { | |
930 | /* Ci M Cj = Ci if (i == j) | |
931 | Ci M Cj = VARYING if (i != j) | |
932 | ||
933 | For INTEGER_CSTs mask unequal bits. If no equal bits remain, | |
934 | drop to varying. */ | |
935 | val1->mask | |
936 | = double_int_ior (double_int_ior (val1->mask, | |
937 | val2->mask), | |
938 | double_int_xor (tree_to_double_int (val1->value), | |
939 | tree_to_double_int (val2->value))); | |
940 | if (double_int_minus_one_p (val1->mask)) | |
941 | { | |
942 | val1->lattice_val = VARYING; | |
943 | val1->value = NULL_TREE; | |
944 | } | |
945 | } | |
0bca51f0 DN |
946 | else if (val1->lattice_val == CONSTANT |
947 | && val2->lattice_val == CONSTANT | |
dce2b2f6 | 948 | && simple_cst_equal (val1->value, val2->value) == 1) |
750628d8 | 949 | { |
0bca51f0 DN |
950 | /* Ci M Cj = Ci if (i == j) |
951 | Ci M Cj = VARYING if (i != j) | |
952 | ||
0b4b14ac RG |
953 | VAL1 already contains the value we want for equivalent values. */ |
954 | } | |
955 | else if (val1->lattice_val == CONSTANT | |
956 | && val2->lattice_val == CONSTANT | |
957 | && (TREE_CODE (val1->value) == ADDR_EXPR | |
958 | || TREE_CODE (val2->value) == ADDR_EXPR)) | |
959 | { | |
960 | /* When not equal addresses are involved try meeting for | |
961 | alignment. */ | |
962 | prop_value_t tem = *val2; | |
963 | if (TREE_CODE (val1->value) == ADDR_EXPR) | |
964 | *val1 = get_value_for_expr (val1->value, true); | |
965 | if (TREE_CODE (val2->value) == ADDR_EXPR) | |
966 | tem = get_value_for_expr (val2->value, true); | |
967 | ccp_lattice_meet (val1, &tem); | |
750628d8 DN |
968 | } |
969 | else | |
970 | { | |
0bca51f0 DN |
971 | /* Any other combination is VARYING. */ |
972 | val1->lattice_val = VARYING; | |
0b4b14ac | 973 | val1->mask = double_int_minus_one; |
0bca51f0 | 974 | val1->value = NULL_TREE; |
750628d8 | 975 | } |
6de9cd9a DN |
976 | } |
977 | ||
978 | ||
750628d8 DN |
979 | /* Loop through the PHI_NODE's parameters for BLOCK and compare their |
980 | lattice values to determine PHI_NODE's lattice value. The value of a | |
0bca51f0 | 981 | PHI node is determined calling ccp_lattice_meet with all the arguments |
750628d8 | 982 | of the PHI node that are incoming via executable edges. */ |
6de9cd9a | 983 | |
750628d8 | 984 | static enum ssa_prop_result |
726a989a | 985 | ccp_visit_phi_node (gimple phi) |
6de9cd9a | 986 | { |
726a989a | 987 | unsigned i; |
0bca51f0 | 988 | prop_value_t *old_val, new_val; |
6de9cd9a | 989 | |
750628d8 | 990 | if (dump_file && (dump_flags & TDF_DETAILS)) |
6de9cd9a | 991 | { |
750628d8 | 992 | fprintf (dump_file, "\nVisiting PHI node: "); |
726a989a | 993 | print_gimple_stmt (dump_file, phi, 0, dump_flags); |
6de9cd9a | 994 | } |
6de9cd9a | 995 | |
726a989a | 996 | old_val = get_value (gimple_phi_result (phi)); |
750628d8 DN |
997 | switch (old_val->lattice_val) |
998 | { | |
999 | case VARYING: | |
0bca51f0 | 1000 | return SSA_PROP_VARYING; |
6de9cd9a | 1001 | |
750628d8 DN |
1002 | case CONSTANT: |
1003 | new_val = *old_val; | |
1004 | break; | |
6de9cd9a | 1005 | |
750628d8 | 1006 | case UNDEFINED: |
750628d8 | 1007 | new_val.lattice_val = UNDEFINED; |
0bca51f0 | 1008 | new_val.value = NULL_TREE; |
750628d8 | 1009 | break; |
6de9cd9a | 1010 | |
750628d8 | 1011 | default: |
1e128c5f | 1012 | gcc_unreachable (); |
750628d8 | 1013 | } |
6de9cd9a | 1014 | |
726a989a | 1015 | for (i = 0; i < gimple_phi_num_args (phi); i++) |
750628d8 | 1016 | { |
0bca51f0 DN |
1017 | /* Compute the meet operator over all the PHI arguments flowing |
1018 | through executable edges. */ | |
726a989a | 1019 | edge e = gimple_phi_arg_edge (phi, i); |
6de9cd9a | 1020 | |
750628d8 DN |
1021 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1022 | { | |
1023 | fprintf (dump_file, | |
1024 | "\n Argument #%d (%d -> %d %sexecutable)\n", | |
1025 | i, e->src->index, e->dest->index, | |
1026 | (e->flags & EDGE_EXECUTABLE) ? "" : "not "); | |
1027 | } | |
1028 | ||
1029 | /* If the incoming edge is executable, Compute the meet operator for | |
1030 | the existing value of the PHI node and the current PHI argument. */ | |
1031 | if (e->flags & EDGE_EXECUTABLE) | |
1032 | { | |
726a989a | 1033 | tree arg = gimple_phi_arg (phi, i)->def; |
0b4b14ac | 1034 | prop_value_t arg_val = get_value_for_expr (arg, false); |
6de9cd9a | 1035 | |
0bca51f0 | 1036 | ccp_lattice_meet (&new_val, &arg_val); |
6de9cd9a | 1037 | |
750628d8 DN |
1038 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1039 | { | |
1040 | fprintf (dump_file, "\t"); | |
0bca51f0 DN |
1041 | print_generic_expr (dump_file, arg, dump_flags); |
1042 | dump_lattice_value (dump_file, "\tValue: ", arg_val); | |
750628d8 DN |
1043 | fprintf (dump_file, "\n"); |
1044 | } | |
6de9cd9a | 1045 | |
750628d8 DN |
1046 | if (new_val.lattice_val == VARYING) |
1047 | break; | |
1048 | } | |
1049 | } | |
6de9cd9a DN |
1050 | |
1051 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
750628d8 DN |
1052 | { |
1053 | dump_lattice_value (dump_file, "\n PHI node value: ", new_val); | |
1054 | fprintf (dump_file, "\n\n"); | |
1055 | } | |
1056 | ||
106dec71 | 1057 | /* Make the transition to the new value. */ |
726a989a | 1058 | if (set_lattice_value (gimple_phi_result (phi), new_val)) |
750628d8 DN |
1059 | { |
1060 | if (new_val.lattice_val == VARYING) | |
1061 | return SSA_PROP_VARYING; | |
1062 | else | |
1063 | return SSA_PROP_INTERESTING; | |
1064 | } | |
1065 | else | |
1066 | return SSA_PROP_NOT_INTERESTING; | |
6de9cd9a DN |
1067 | } |
1068 | ||
84d77ca6 | 1069 | /* Return the constant value for OP or OP otherwise. */ |
0354c0c7 BS |
1070 | |
1071 | static tree | |
84d77ca6 | 1072 | valueize_op (tree op) |
0354c0c7 | 1073 | { |
0354c0c7 BS |
1074 | if (TREE_CODE (op) == SSA_NAME) |
1075 | { | |
84d77ca6 RG |
1076 | tree tem = get_constant_value (op); |
1077 | if (tem) | |
1078 | return tem; | |
0354c0c7 BS |
1079 | } |
1080 | return op; | |
1081 | } | |
1082 | ||
750628d8 DN |
1083 | /* CCP specific front-end to the non-destructive constant folding |
1084 | routines. | |
6de9cd9a DN |
1085 | |
1086 | Attempt to simplify the RHS of STMT knowing that one or more | |
1087 | operands are constants. | |
1088 | ||
1089 | If simplification is possible, return the simplified RHS, | |
726a989a | 1090 | otherwise return the original RHS or NULL_TREE. */ |
6de9cd9a DN |
1091 | |
1092 | static tree | |
726a989a | 1093 | ccp_fold (gimple stmt) |
6de9cd9a | 1094 | { |
db3927fb | 1095 | location_t loc = gimple_location (stmt); |
726a989a | 1096 | switch (gimple_code (stmt)) |
0bca51f0 | 1097 | { |
726a989a RB |
1098 | case GIMPLE_ASSIGN: |
1099 | { | |
1100 | enum tree_code subcode = gimple_assign_rhs_code (stmt); | |
1101 | ||
1102 | switch (get_gimple_rhs_class (subcode)) | |
1103 | { | |
1104 | case GIMPLE_SINGLE_RHS: | |
1105 | { | |
1106 | tree rhs = gimple_assign_rhs1 (stmt); | |
1107 | enum tree_code_class kind = TREE_CODE_CLASS (subcode); | |
1108 | ||
1109 | if (TREE_CODE (rhs) == SSA_NAME) | |
1110 | { | |
1111 | /* If the RHS is an SSA_NAME, return its known constant value, | |
1112 | if any. */ | |
84d77ca6 | 1113 | return get_constant_value (rhs); |
726a989a RB |
1114 | } |
1115 | /* Handle propagating invariant addresses into address operations. | |
1116 | The folding we do here matches that in tree-ssa-forwprop.c. */ | |
1117 | else if (TREE_CODE (rhs) == ADDR_EXPR) | |
1118 | { | |
1119 | tree *base; | |
1120 | base = &TREE_OPERAND (rhs, 0); | |
1121 | while (handled_component_p (*base)) | |
1122 | base = &TREE_OPERAND (*base, 0); | |
70f34814 | 1123 | if (TREE_CODE (*base) == MEM_REF |
726a989a RB |
1124 | && TREE_CODE (TREE_OPERAND (*base, 0)) == SSA_NAME) |
1125 | { | |
84d77ca6 RG |
1126 | tree val = get_constant_value (TREE_OPERAND (*base, 0)); |
1127 | if (val | |
1128 | && TREE_CODE (val) == ADDR_EXPR) | |
726a989a | 1129 | { |
70f34814 RG |
1130 | tree ret, save = *base; |
1131 | tree new_base; | |
1132 | new_base = fold_build2 (MEM_REF, TREE_TYPE (*base), | |
84d77ca6 | 1133 | unshare_expr (val), |
70f34814 | 1134 | TREE_OPERAND (*base, 1)); |
726a989a RB |
1135 | /* We need to return a new tree, not modify the IL |
1136 | or share parts of it. So play some tricks to | |
1137 | avoid manually building it. */ | |
70f34814 | 1138 | *base = new_base; |
726a989a RB |
1139 | ret = unshare_expr (rhs); |
1140 | recompute_tree_invariant_for_addr_expr (ret); | |
1141 | *base = save; | |
1142 | return ret; | |
1143 | } | |
1144 | } | |
1145 | } | |
23977d3c RG |
1146 | else if (TREE_CODE (rhs) == CONSTRUCTOR |
1147 | && TREE_CODE (TREE_TYPE (rhs)) == VECTOR_TYPE | |
1148 | && (CONSTRUCTOR_NELTS (rhs) | |
1149 | == TYPE_VECTOR_SUBPARTS (TREE_TYPE (rhs)))) | |
1150 | { | |
1151 | unsigned i; | |
1152 | tree val, list; | |
1153 | ||
1154 | list = NULL_TREE; | |
1155 | FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (rhs), i, val) | |
1156 | { | |
84d77ca6 | 1157 | val = valueize_op (val); |
23977d3c RG |
1158 | if (TREE_CODE (val) == INTEGER_CST |
1159 | || TREE_CODE (val) == REAL_CST | |
1160 | || TREE_CODE (val) == FIXED_CST) | |
1161 | list = tree_cons (NULL_TREE, val, list); | |
1162 | else | |
1163 | return NULL_TREE; | |
1164 | } | |
1165 | ||
1166 | return build_vector (TREE_TYPE (rhs), nreverse (list)); | |
1167 | } | |
6de9cd9a | 1168 | |
726a989a | 1169 | if (kind == tcc_reference) |
c76a1f18 | 1170 | { |
4bad83f5 RG |
1171 | if ((TREE_CODE (rhs) == VIEW_CONVERT_EXPR |
1172 | || TREE_CODE (rhs) == REALPART_EXPR | |
1173 | || TREE_CODE (rhs) == IMAGPART_EXPR) | |
c76a1f18 RG |
1174 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME) |
1175 | { | |
84d77ca6 RG |
1176 | tree val = get_constant_value (TREE_OPERAND (rhs, 0)); |
1177 | if (val) | |
db3927fb | 1178 | return fold_unary_loc (EXPR_LOCATION (rhs), |
84d77ca6 RG |
1179 | TREE_CODE (rhs), |
1180 | TREE_TYPE (rhs), val); | |
c76a1f18 | 1181 | } |
70f34814 | 1182 | else if (TREE_CODE (rhs) == MEM_REF |
e8114fba RG |
1183 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME) |
1184 | { | |
84d77ca6 RG |
1185 | tree val = get_constant_value (TREE_OPERAND (rhs, 0)); |
1186 | if (val | |
1187 | && TREE_CODE (val) == ADDR_EXPR) | |
70f34814 RG |
1188 | { |
1189 | tree tem = fold_build2 (MEM_REF, TREE_TYPE (rhs), | |
84d77ca6 | 1190 | unshare_expr (val), |
70f34814 RG |
1191 | TREE_OPERAND (rhs, 1)); |
1192 | if (tem) | |
1193 | rhs = tem; | |
1194 | } | |
e8114fba | 1195 | } |
c76a1f18 RG |
1196 | return fold_const_aggregate_ref (rhs); |
1197 | } | |
726a989a RB |
1198 | else if (kind == tcc_declaration) |
1199 | return get_symbol_constant_value (rhs); | |
1200 | return rhs; | |
1201 | } | |
b8698a0f | 1202 | |
726a989a RB |
1203 | case GIMPLE_UNARY_RHS: |
1204 | { | |
1205 | /* Handle unary operators that can appear in GIMPLE form. | |
1206 | Note that we know the single operand must be a constant, | |
1207 | so this should almost always return a simplified RHS. */ | |
1208 | tree lhs = gimple_assign_lhs (stmt); | |
84d77ca6 | 1209 | tree op0 = valueize_op (gimple_assign_rhs1 (stmt)); |
726a989a RB |
1210 | |
1211 | /* Conversions are useless for CCP purposes if they are | |
1212 | value-preserving. Thus the restrictions that | |
1213 | useless_type_conversion_p places for pointer type conversions | |
1214 | do not apply here. Substitution later will only substitute to | |
1215 | allowed places. */ | |
1a87cf0c | 1216 | if (CONVERT_EXPR_CODE_P (subcode) |
99f536cc | 1217 | && POINTER_TYPE_P (TREE_TYPE (lhs)) |
70f34814 | 1218 | && POINTER_TYPE_P (TREE_TYPE (op0))) |
99f536cc RG |
1219 | { |
1220 | tree tem; | |
70f34814 | 1221 | /* Try to re-construct array references on-the-fly. */ |
99f536cc RG |
1222 | if (!useless_type_conversion_p (TREE_TYPE (lhs), |
1223 | TREE_TYPE (op0)) | |
1224 | && ((tem = maybe_fold_offset_to_address | |
db3927fb | 1225 | (loc, |
c2255bc4 | 1226 | op0, integer_zero_node, TREE_TYPE (lhs))) |
99f536cc RG |
1227 | != NULL_TREE)) |
1228 | return tem; | |
1229 | return op0; | |
1230 | } | |
726a989a | 1231 | |
b8698a0f | 1232 | return |
db3927fb AH |
1233 | fold_unary_ignore_overflow_loc (loc, subcode, |
1234 | gimple_expr_type (stmt), op0); | |
ff8b183b | 1235 | } |
726a989a RB |
1236 | |
1237 | case GIMPLE_BINARY_RHS: | |
1238 | { | |
1239 | /* Handle binary operators that can appear in GIMPLE form. */ | |
84d77ca6 RG |
1240 | tree op0 = valueize_op (gimple_assign_rhs1 (stmt)); |
1241 | tree op1 = valueize_op (gimple_assign_rhs2 (stmt)); | |
726a989a | 1242 | |
70f34814 RG |
1243 | /* Translate &x + CST into an invariant form suitable for |
1244 | further propagation. */ | |
99f536cc RG |
1245 | if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR |
1246 | && TREE_CODE (op0) == ADDR_EXPR | |
1247 | && TREE_CODE (op1) == INTEGER_CST) | |
1248 | { | |
70f34814 RG |
1249 | tree off = fold_convert (ptr_type_node, op1); |
1250 | return build_fold_addr_expr | |
1251 | (fold_build2 (MEM_REF, | |
1252 | TREE_TYPE (TREE_TYPE (op0)), | |
1253 | unshare_expr (op0), off)); | |
99f536cc RG |
1254 | } |
1255 | ||
db3927fb | 1256 | return fold_binary_loc (loc, subcode, |
70f34814 | 1257 | gimple_expr_type (stmt), op0, op1); |
726a989a RB |
1258 | } |
1259 | ||
0354c0c7 BS |
1260 | case GIMPLE_TERNARY_RHS: |
1261 | { | |
84d77ca6 RG |
1262 | /* Handle ternary operators that can appear in GIMPLE form. */ |
1263 | tree op0 = valueize_op (gimple_assign_rhs1 (stmt)); | |
1264 | tree op1 = valueize_op (gimple_assign_rhs2 (stmt)); | |
1265 | tree op2 = valueize_op (gimple_assign_rhs3 (stmt)); | |
0354c0c7 BS |
1266 | |
1267 | return fold_ternary_loc (loc, subcode, | |
1268 | gimple_expr_type (stmt), op0, op1, op2); | |
1269 | } | |
1270 | ||
726a989a RB |
1271 | default: |
1272 | gcc_unreachable (); | |
1273 | } | |
1274 | } | |
1275 | break; | |
6de9cd9a | 1276 | |
726a989a | 1277 | case GIMPLE_CALL: |
174ef36d | 1278 | { |
84d77ca6 | 1279 | tree fn = valueize_op (gimple_call_fn (stmt)); |
174ef36d | 1280 | if (TREE_CODE (fn) == ADDR_EXPR |
a135b1c4 | 1281 | && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL |
174ef36d RG |
1282 | && DECL_BUILT_IN (TREE_OPERAND (fn, 0))) |
1283 | { | |
1284 | tree *args = XALLOCAVEC (tree, gimple_call_num_args (stmt)); | |
1285 | tree call, retval; | |
1286 | unsigned i; | |
1287 | for (i = 0; i < gimple_call_num_args (stmt); ++i) | |
84d77ca6 | 1288 | args[i] = valueize_op (gimple_call_arg (stmt, i)); |
db3927fb AH |
1289 | call = build_call_array_loc (loc, |
1290 | gimple_call_return_type (stmt), | |
1291 | fn, gimple_call_num_args (stmt), args); | |
1292 | retval = fold_call_expr (EXPR_LOCATION (call), call, false); | |
174ef36d RG |
1293 | if (retval) |
1294 | /* fold_call_expr wraps the result inside a NOP_EXPR. */ | |
1295 | STRIP_NOPS (retval); | |
1296 | return retval; | |
1297 | } | |
1298 | return NULL_TREE; | |
1299 | } | |
6de9cd9a | 1300 | |
726a989a RB |
1301 | case GIMPLE_COND: |
1302 | { | |
1303 | /* Handle comparison operators that can appear in GIMPLE form. */ | |
84d77ca6 RG |
1304 | tree op0 = valueize_op (gimple_cond_lhs (stmt)); |
1305 | tree op1 = valueize_op (gimple_cond_rhs (stmt)); | |
726a989a | 1306 | enum tree_code code = gimple_cond_code (stmt); |
db3927fb | 1307 | return fold_binary_loc (loc, code, boolean_type_node, op0, op1); |
726a989a | 1308 | } |
6de9cd9a | 1309 | |
726a989a RB |
1310 | case GIMPLE_SWITCH: |
1311 | { | |
84d77ca6 RG |
1312 | /* Return the constant switch index. */ |
1313 | return valueize_op (gimple_switch_index (stmt)); | |
726a989a | 1314 | } |
00d382a8 | 1315 | |
726a989a RB |
1316 | default: |
1317 | gcc_unreachable (); | |
6de9cd9a | 1318 | } |
6de9cd9a DN |
1319 | } |
1320 | ||
e196b221 | 1321 | /* See if we can find constructor defining value of BASE. |
4a2da105 JH |
1322 | When we know the consructor with constant offset (such as |
1323 | base is array[40] and we do know constructor of array), then | |
1324 | BIT_OFFSET is adjusted accordingly. | |
e196b221 JH |
1325 | |
1326 | As a special case, return error_mark_node when constructor | |
1327 | is not explicitly available, but it is known to be zero | |
1328 | such as 'static const int a;'. */ | |
1329 | static tree | |
4a2da105 | 1330 | get_base_constructor (tree base, HOST_WIDE_INT *bit_offset) |
e196b221 | 1331 | { |
4a2da105 | 1332 | HOST_WIDE_INT bit_offset2, size, max_size; |
e196b221 JH |
1333 | if (TREE_CODE (base) == MEM_REF) |
1334 | { | |
1335 | if (!integer_zerop (TREE_OPERAND (base, 1))) | |
4a2da105 JH |
1336 | { |
1337 | if (!host_integerp (TREE_OPERAND (base, 1), 0)) | |
1338 | return NULL_TREE; | |
1339 | *bit_offset += (mem_ref_offset (base).low | |
1340 | * BITS_PER_UNIT); | |
1341 | } | |
e196b221 JH |
1342 | |
1343 | base = get_constant_value (TREE_OPERAND (base, 0)); | |
1344 | if (!base || TREE_CODE (base) != ADDR_EXPR) | |
1345 | return NULL_TREE; | |
1346 | base = TREE_OPERAND (base, 0); | |
1347 | } | |
1348 | ||
1349 | /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its | |
1350 | DECL_INITIAL. If BASE is a nested reference into another | |
1351 | ARRAY_REF or COMPONENT_REF, make a recursive call to resolve | |
1352 | the inner reference. */ | |
1353 | switch (TREE_CODE (base)) | |
1354 | { | |
1355 | case VAR_DECL: | |
64e0f5ff | 1356 | if (!const_value_known_p (base)) |
e196b221 JH |
1357 | return NULL_TREE; |
1358 | ||
1359 | /* Fallthru. */ | |
1360 | case CONST_DECL: | |
1361 | if (!DECL_INITIAL (base) | |
1362 | && (TREE_STATIC (base) || DECL_EXTERNAL (base))) | |
1363 | return error_mark_node; | |
1364 | return DECL_INITIAL (base); | |
1365 | ||
1366 | break; | |
1367 | ||
1368 | case ARRAY_REF: | |
1369 | case COMPONENT_REF: | |
4a2da105 JH |
1370 | base = get_ref_base_and_extent (base, &bit_offset2, &size, &max_size); |
1371 | if (max_size == -1 || size != max_size) | |
1372 | return NULL_TREE; | |
1373 | *bit_offset += bit_offset2; | |
1374 | return get_base_constructor (base, bit_offset); | |
e196b221 JH |
1375 | break; |
1376 | ||
1377 | case STRING_CST: | |
1378 | case CONSTRUCTOR: | |
1379 | return base; | |
1380 | break; | |
1381 | ||
1382 | default: | |
1383 | return NULL_TREE; | |
1384 | } | |
1385 | } | |
1386 | ||
697c3575 JH |
1387 | /* CTOR is STRING_CST. Fold reference of type TYPE and size SIZE |
1388 | to the memory at bit OFFSET. | |
1389 | ||
1390 | We do only simple job of folding byte accesses. */ | |
1391 | ||
1392 | static tree | |
1393 | fold_string_cst_ctor_reference (tree type, tree ctor, unsigned HOST_WIDE_INT offset, | |
1394 | unsigned HOST_WIDE_INT size) | |
1395 | { | |
1396 | if (INTEGRAL_TYPE_P (type) | |
1397 | && (TYPE_MODE (type) | |
1398 | == TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1399 | && (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1400 | == MODE_INT) | |
1401 | && GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) == 1 | |
1402 | && size == BITS_PER_UNIT | |
1403 | && !(offset % BITS_PER_UNIT)) | |
1404 | { | |
1405 | offset /= BITS_PER_UNIT; | |
1406 | if (offset < (unsigned HOST_WIDE_INT) TREE_STRING_LENGTH (ctor)) | |
1407 | return build_int_cst_type (type, (TREE_STRING_POINTER (ctor) | |
1408 | [offset])); | |
1409 | /* Folding | |
1410 | const char a[20]="hello"; | |
1411 | return a[10]; | |
1412 | ||
1413 | might lead to offset greater than string length. In this case we | |
1414 | know value is either initialized to 0 or out of bounds. Return 0 | |
1415 | in both cases. */ | |
1416 | return build_zero_cst (type); | |
1417 | } | |
1418 | return NULL_TREE; | |
1419 | } | |
1420 | ||
1421 | /* CTOR is CONSTRUCTOR of an array type. Fold reference of type TYPE and size | |
1422 | SIZE to the memory at bit OFFSET. */ | |
1423 | ||
1424 | static tree | |
1425 | fold_array_ctor_reference (tree type, tree ctor, | |
1426 | unsigned HOST_WIDE_INT offset, | |
1427 | unsigned HOST_WIDE_INT size) | |
1428 | { | |
1429 | unsigned HOST_WIDE_INT cnt; | |
1430 | tree cfield, cval; | |
1431 | double_int low_bound, elt_size; | |
1432 | double_int index, max_index; | |
1433 | double_int access_index; | |
1434 | tree domain_type = TYPE_DOMAIN (TREE_TYPE (ctor)); | |
1435 | HOST_WIDE_INT inner_offset; | |
1436 | ||
1437 | /* Compute low bound and elt size. */ | |
1438 | if (domain_type && TYPE_MIN_VALUE (domain_type)) | |
1439 | { | |
1440 | /* Static constructors for variably sized objects makes no sense. */ | |
1441 | gcc_assert (TREE_CODE (TYPE_MIN_VALUE (domain_type)) == INTEGER_CST); | |
1442 | low_bound = tree_to_double_int (TYPE_MIN_VALUE (domain_type)); | |
1443 | } | |
1444 | else | |
1445 | low_bound = double_int_zero; | |
1446 | /* Static constructors for variably sized objects makes no sense. */ | |
1447 | gcc_assert (TREE_CODE(TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (ctor)))) | |
1448 | == INTEGER_CST); | |
1449 | elt_size = | |
1450 | tree_to_double_int (TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (ctor)))); | |
1451 | ||
1452 | ||
1453 | /* We can handle only constantly sized accesses that are known to not | |
1454 | be larger than size of array element. */ | |
1455 | if (!TYPE_SIZE_UNIT (type) | |
1456 | || TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST | |
1457 | || double_int_cmp (elt_size, | |
1458 | tree_to_double_int (TYPE_SIZE_UNIT (type)), 0) < 0) | |
1459 | return NULL_TREE; | |
1460 | ||
1461 | /* Compute the array index we look for. */ | |
1462 | access_index = double_int_udiv (uhwi_to_double_int (offset / BITS_PER_UNIT), | |
1463 | elt_size, TRUNC_DIV_EXPR); | |
1464 | access_index = double_int_add (access_index, low_bound); | |
1465 | ||
1466 | /* And offset within the access. */ | |
1467 | inner_offset = offset % (double_int_to_uhwi (elt_size) * BITS_PER_UNIT); | |
1468 | ||
1469 | /* See if the array field is large enough to span whole access. We do not | |
1470 | care to fold accesses spanning multiple array indexes. */ | |
1471 | if (inner_offset + size > double_int_to_uhwi (elt_size) * BITS_PER_UNIT) | |
1472 | return NULL_TREE; | |
1473 | ||
1474 | index = double_int_sub (low_bound, double_int_one); | |
1475 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) | |
1476 | { | |
1477 | /* Array constructor might explicitely set index, or specify range | |
1478 | or leave index NULL meaning that it is next index after previous | |
1479 | one. */ | |
1480 | if (cfield) | |
1481 | { | |
1482 | if (TREE_CODE (cfield) == INTEGER_CST) | |
1483 | max_index = index = tree_to_double_int (cfield); | |
1484 | else | |
1485 | { | |
1486 | gcc_assert (TREE_CODE (cfield) == RANGE_EXPR); | |
1487 | index = tree_to_double_int (TREE_OPERAND (cfield, 0)); | |
1488 | max_index = tree_to_double_int (TREE_OPERAND (cfield, 1)); | |
1489 | } | |
1490 | } | |
1491 | else | |
1492 | max_index = index = double_int_add (index, double_int_one); | |
1493 | ||
1494 | /* Do we have match? */ | |
1495 | if (double_int_cmp (access_index, index, 1) >= 0 | |
1496 | && double_int_cmp (access_index, max_index, 1) <= 0) | |
1497 | return fold_ctor_reference (type, cval, inner_offset, size); | |
1498 | } | |
1499 | /* When memory is not explicitely mentioned in constructor, | |
1500 | it is 0 (or out of range). */ | |
1501 | return build_zero_cst (type); | |
1502 | } | |
1503 | ||
1504 | /* CTOR is CONSTRUCTOR of an aggregate or vector. | |
1505 | Fold reference of type TYPE and size SIZE to the memory at bit OFFSET. */ | |
1506 | ||
1507 | static tree | |
1508 | fold_nonarray_ctor_reference (tree type, tree ctor, | |
1509 | unsigned HOST_WIDE_INT offset, | |
1510 | unsigned HOST_WIDE_INT size) | |
1511 | { | |
1512 | unsigned HOST_WIDE_INT cnt; | |
1513 | tree cfield, cval; | |
1514 | ||
1515 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, | |
1516 | cval) | |
1517 | { | |
1518 | tree byte_offset = DECL_FIELD_OFFSET (cfield); | |
1519 | tree field_offset = DECL_FIELD_BIT_OFFSET (cfield); | |
1520 | tree field_size = DECL_SIZE (cfield); | |
1521 | double_int bitoffset; | |
1522 | double_int byte_offset_cst = tree_to_double_int (byte_offset); | |
1523 | double_int bits_per_unit_cst = uhwi_to_double_int (BITS_PER_UNIT); | |
1524 | double_int bitoffset_end; | |
1525 | ||
1526 | /* Variable sized objects in static constructors makes no sense. */ | |
1527 | gcc_assert (TREE_CODE (field_offset) == INTEGER_CST | |
1528 | && TREE_CODE (byte_offset) == INTEGER_CST | |
1529 | && TREE_CODE (field_size) == INTEGER_CST); | |
1530 | ||
1531 | /* Compute bit offset of the field. */ | |
1532 | bitoffset = double_int_add (tree_to_double_int (field_offset), | |
1533 | double_int_mul (byte_offset_cst, | |
1534 | bits_per_unit_cst)); | |
1535 | /* Compute bit offset where the field ends. */ | |
1536 | bitoffset_end = double_int_add (bitoffset, | |
1537 | tree_to_double_int (field_size)); | |
1538 | ||
1539 | /* Is OFFSET in the range (BITOFFSET, BITOFFSET_END)? */ | |
1540 | if (double_int_cmp (uhwi_to_double_int (offset), bitoffset, 0) >= 0 | |
1541 | && double_int_cmp (uhwi_to_double_int (offset), | |
1542 | bitoffset_end, 0) < 0) | |
1543 | { | |
1544 | double_int access_end = double_int_add (uhwi_to_double_int (offset), | |
1545 | uhwi_to_double_int (size)); | |
1546 | double_int inner_offset = double_int_sub (uhwi_to_double_int (offset), | |
1547 | bitoffset); | |
1548 | /* We do have overlap. Now see if field is large enough to | |
1549 | cover the access. Give up for accesses spanning multiple | |
1550 | fields. */ | |
1551 | if (double_int_cmp (access_end, bitoffset_end, 0) > 0) | |
1552 | return NULL_TREE; | |
1553 | return fold_ctor_reference (type, cval, | |
1554 | double_int_to_uhwi (inner_offset), size); | |
1555 | } | |
1556 | } | |
1557 | /* When memory is not explicitely mentioned in constructor, it is 0. */ | |
1558 | return build_zero_cst (type); | |
1559 | } | |
1560 | ||
1561 | /* CTOR is value initializing memory, fold reference of type TYPE and size SIZE | |
1562 | to the memory at bit OFFSET. */ | |
1563 | ||
1564 | static tree | |
1565 | fold_ctor_reference (tree type, tree ctor, unsigned HOST_WIDE_INT offset, | |
1566 | unsigned HOST_WIDE_INT size) | |
1567 | { | |
1568 | tree ret; | |
1569 | ||
1570 | /* We found the field with exact match. */ | |
1571 | if (useless_type_conversion_p (type, TREE_TYPE (ctor)) | |
1572 | && !offset) | |
1573 | return canonicalize_constructor_val (ctor); | |
1574 | ||
1575 | /* We are at the end of walk, see if we can view convert the | |
1576 | result. */ | |
1577 | if (!AGGREGATE_TYPE_P (TREE_TYPE (ctor)) && !offset | |
1578 | /* VIEW_CONVERT_EXPR is defined only for matching sizes. */ | |
1579 | && operand_equal_p (TYPE_SIZE (type), | |
1580 | TYPE_SIZE (TREE_TYPE (ctor)), 0)) | |
1581 | { | |
1582 | ret = canonicalize_constructor_val (ctor); | |
1583 | ret = fold_unary (VIEW_CONVERT_EXPR, type, ret); | |
1584 | if (ret) | |
1585 | STRIP_NOPS (ret); | |
1586 | return ret; | |
1587 | } | |
1588 | if (TREE_CODE (ctor) == STRING_CST) | |
1589 | return fold_string_cst_ctor_reference (type, ctor, offset, size); | |
1590 | if (TREE_CODE (ctor) == CONSTRUCTOR) | |
1591 | { | |
1592 | ||
1593 | if (TREE_CODE (TREE_TYPE (ctor)) == ARRAY_TYPE) | |
1594 | return fold_array_ctor_reference (type, ctor, offset, size); | |
1595 | else | |
1596 | return fold_nonarray_ctor_reference (type, ctor, offset, size); | |
1597 | } | |
1598 | ||
1599 | return NULL_TREE; | |
1600 | } | |
1601 | ||
ae3df618 SB |
1602 | /* Return the tree representing the element referenced by T if T is an |
1603 | ARRAY_REF or COMPONENT_REF into constant aggregates. Return | |
1604 | NULL_TREE otherwise. */ | |
1605 | ||
ed97ddc6 | 1606 | tree |
ae3df618 SB |
1607 | fold_const_aggregate_ref (tree t) |
1608 | { | |
697c3575 JH |
1609 | tree ctor, idx, base; |
1610 | HOST_WIDE_INT offset, size, max_size; | |
84d77ca6 | 1611 | tree tem; |
ae3df618 | 1612 | |
e8114fba RG |
1613 | if (TREE_CODE_CLASS (TREE_CODE (t)) == tcc_declaration) |
1614 | return get_symbol_constant_value (t); | |
1615 | ||
17f39a39 JH |
1616 | tem = fold_read_from_constant_string (t); |
1617 | if (tem) | |
1618 | return tem; | |
1619 | ||
ae3df618 SB |
1620 | switch (TREE_CODE (t)) |
1621 | { | |
1622 | case ARRAY_REF: | |
697c3575 JH |
1623 | case ARRAY_RANGE_REF: |
1624 | /* Constant indexes are handled well by get_base_constructor. | |
1625 | Only special case variable offsets. | |
1626 | FIXME: This code can't handle nested references with variable indexes | |
1627 | (they will be handled only by iteration of ccp). Perhaps we can bring | |
1628 | get_ref_base_and_extent here and make it use get_constant_value. */ | |
1629 | if (TREE_CODE (TREE_OPERAND (t, 1)) == SSA_NAME | |
1630 | && (idx = get_constant_value (TREE_OPERAND (t, 1))) | |
1631 | && host_integerp (idx, 0)) | |
1632 | { | |
1633 | tree low_bound, unit_size; | |
ae3df618 | 1634 | |
697c3575 JH |
1635 | /* If the resulting bit-offset is constant, track it. */ |
1636 | if ((low_bound = array_ref_low_bound (t), | |
1637 | host_integerp (low_bound, 0)) | |
1638 | && (unit_size = array_ref_element_size (t), | |
1639 | host_integerp (unit_size, 1))) | |
1640 | { | |
1641 | offset = TREE_INT_CST_LOW (idx); | |
1642 | offset -= TREE_INT_CST_LOW (low_bound); | |
1643 | offset *= TREE_INT_CST_LOW (unit_size); | |
1644 | offset *= BITS_PER_UNIT; | |
1645 | ||
1646 | base = TREE_OPERAND (t, 0); | |
4a2da105 | 1647 | ctor = get_base_constructor (base, &offset); |
697c3575 JH |
1648 | /* Empty constructor. Always fold to 0. */ |
1649 | if (ctor == error_mark_node) | |
1650 | return build_zero_cst (TREE_TYPE (t)); | |
1651 | /* Out of bound array access. Value is undefined, but don't fold. */ | |
1652 | if (offset < 0) | |
1653 | return NULL_TREE; | |
1654 | /* We can not determine ctor. */ | |
1655 | if (!ctor) | |
1656 | return NULL_TREE; | |
1657 | return fold_ctor_reference (TREE_TYPE (t), ctor, offset, | |
1658 | TREE_INT_CST_LOW (unit_size) | |
1659 | * BITS_PER_UNIT); | |
1660 | } | |
1661 | } | |
1662 | /* Fallthru. */ | |
1663 | ||
1664 | case COMPONENT_REF: | |
1665 | case BIT_FIELD_REF: | |
1666 | case TARGET_MEM_REF: | |
1667 | case MEM_REF: | |
1668 | base = get_ref_base_and_extent (t, &offset, &size, &max_size); | |
4a2da105 | 1669 | ctor = get_base_constructor (base, &offset); |
87e1e42b | 1670 | |
697c3575 | 1671 | /* Empty constructor. Always fold to 0. */ |
e196b221 JH |
1672 | if (ctor == error_mark_node) |
1673 | return build_zero_cst (TREE_TYPE (t)); | |
697c3575 JH |
1674 | /* We do not know precise address. */ |
1675 | if (max_size == -1 || max_size != size) | |
1676 | return NULL_TREE; | |
1677 | /* We can not determine ctor. */ | |
1678 | if (!ctor) | |
ae3df618 SB |
1679 | return NULL_TREE; |
1680 | ||
697c3575 JH |
1681 | /* Out of bound array access. Value is undefined, but don't fold. */ |
1682 | if (offset < 0) | |
e196b221 | 1683 | return NULL_TREE; |
ae3df618 | 1684 | |
697c3575 | 1685 | return fold_ctor_reference (TREE_TYPE (t), ctor, offset, size); |
ae3df618 | 1686 | |
1ebd8d9a SB |
1687 | case REALPART_EXPR: |
1688 | case IMAGPART_EXPR: | |
1689 | { | |
1690 | tree c = fold_const_aggregate_ref (TREE_OPERAND (t, 0)); | |
1691 | if (c && TREE_CODE (c) == COMPLEX_CST) | |
db3927fb AH |
1692 | return fold_build1_loc (EXPR_LOCATION (t), |
1693 | TREE_CODE (t), TREE_TYPE (t), c); | |
1ebd8d9a SB |
1694 | break; |
1695 | } | |
87e1e42b | 1696 | |
ae3df618 SB |
1697 | default: |
1698 | break; | |
1699 | } | |
1700 | ||
1701 | return NULL_TREE; | |
1702 | } | |
726a989a | 1703 | |
0b4b14ac RG |
1704 | /* Apply the operation CODE in type TYPE to the value, mask pair |
1705 | RVAL and RMASK representing a value of type RTYPE and set | |
1706 | the value, mask pair *VAL and *MASK to the result. */ | |
1707 | ||
1708 | static void | |
1709 | bit_value_unop_1 (enum tree_code code, tree type, | |
1710 | double_int *val, double_int *mask, | |
1711 | tree rtype, double_int rval, double_int rmask) | |
1712 | { | |
1713 | switch (code) | |
1714 | { | |
1715 | case BIT_NOT_EXPR: | |
1716 | *mask = rmask; | |
1717 | *val = double_int_not (rval); | |
1718 | break; | |
1719 | ||
1720 | case NEGATE_EXPR: | |
1721 | { | |
1722 | double_int temv, temm; | |
1723 | /* Return ~rval + 1. */ | |
1724 | bit_value_unop_1 (BIT_NOT_EXPR, type, &temv, &temm, type, rval, rmask); | |
1725 | bit_value_binop_1 (PLUS_EXPR, type, val, mask, | |
1726 | type, temv, temm, | |
1727 | type, double_int_one, double_int_zero); | |
1728 | break; | |
1729 | } | |
1730 | ||
1731 | CASE_CONVERT: | |
1732 | { | |
1733 | bool uns; | |
1734 | ||
1735 | /* First extend mask and value according to the original type. */ | |
1736 | uns = (TREE_CODE (rtype) == INTEGER_TYPE && TYPE_IS_SIZETYPE (rtype) | |
1737 | ? 0 : TYPE_UNSIGNED (rtype)); | |
1738 | *mask = double_int_ext (rmask, TYPE_PRECISION (rtype), uns); | |
1739 | *val = double_int_ext (rval, TYPE_PRECISION (rtype), uns); | |
1740 | ||
1741 | /* Then extend mask and value according to the target type. */ | |
1742 | uns = (TREE_CODE (type) == INTEGER_TYPE && TYPE_IS_SIZETYPE (type) | |
1743 | ? 0 : TYPE_UNSIGNED (type)); | |
1744 | *mask = double_int_ext (*mask, TYPE_PRECISION (type), uns); | |
1745 | *val = double_int_ext (*val, TYPE_PRECISION (type), uns); | |
1746 | break; | |
1747 | } | |
1748 | ||
1749 | default: | |
1750 | *mask = double_int_minus_one; | |
1751 | break; | |
1752 | } | |
1753 | } | |
1754 | ||
1755 | /* Apply the operation CODE in type TYPE to the value, mask pairs | |
1756 | R1VAL, R1MASK and R2VAL, R2MASK representing a values of type R1TYPE | |
1757 | and R2TYPE and set the value, mask pair *VAL and *MASK to the result. */ | |
1758 | ||
1759 | static void | |
1760 | bit_value_binop_1 (enum tree_code code, tree type, | |
1761 | double_int *val, double_int *mask, | |
1762 | tree r1type, double_int r1val, double_int r1mask, | |
1763 | tree r2type, double_int r2val, double_int r2mask) | |
1764 | { | |
1765 | bool uns = (TREE_CODE (type) == INTEGER_TYPE | |
1766 | && TYPE_IS_SIZETYPE (type) ? 0 : TYPE_UNSIGNED (type)); | |
1767 | /* Assume we'll get a constant result. Use an initial varying value, | |
1768 | we fall back to varying in the end if necessary. */ | |
1769 | *mask = double_int_minus_one; | |
1770 | switch (code) | |
1771 | { | |
1772 | case BIT_AND_EXPR: | |
1773 | /* The mask is constant where there is a known not | |
1774 | set bit, (m1 | m2) & ((v1 | m1) & (v2 | m2)) */ | |
1775 | *mask = double_int_and (double_int_ior (r1mask, r2mask), | |
1776 | double_int_and (double_int_ior (r1val, r1mask), | |
1777 | double_int_ior (r2val, r2mask))); | |
1778 | *val = double_int_and (r1val, r2val); | |
1779 | break; | |
1780 | ||
1781 | case BIT_IOR_EXPR: | |
1782 | /* The mask is constant where there is a known | |
1783 | set bit, (m1 | m2) & ~((v1 & ~m1) | (v2 & ~m2)). */ | |
1784 | *mask = double_int_and_not | |
1785 | (double_int_ior (r1mask, r2mask), | |
1786 | double_int_ior (double_int_and_not (r1val, r1mask), | |
1787 | double_int_and_not (r2val, r2mask))); | |
1788 | *val = double_int_ior (r1val, r2val); | |
1789 | break; | |
1790 | ||
1791 | case BIT_XOR_EXPR: | |
1792 | /* m1 | m2 */ | |
1793 | *mask = double_int_ior (r1mask, r2mask); | |
1794 | *val = double_int_xor (r1val, r2val); | |
1795 | break; | |
1796 | ||
1797 | case LROTATE_EXPR: | |
1798 | case RROTATE_EXPR: | |
1799 | if (double_int_zero_p (r2mask)) | |
1800 | { | |
1801 | HOST_WIDE_INT shift = r2val.low; | |
1802 | if (code == RROTATE_EXPR) | |
1803 | shift = -shift; | |
1804 | *mask = double_int_lrotate (r1mask, shift, TYPE_PRECISION (type)); | |
1805 | *val = double_int_lrotate (r1val, shift, TYPE_PRECISION (type)); | |
1806 | } | |
1807 | break; | |
1808 | ||
1809 | case LSHIFT_EXPR: | |
1810 | case RSHIFT_EXPR: | |
1811 | /* ??? We can handle partially known shift counts if we know | |
1812 | its sign. That way we can tell that (x << (y | 8)) & 255 | |
1813 | is zero. */ | |
1814 | if (double_int_zero_p (r2mask)) | |
1815 | { | |
1816 | HOST_WIDE_INT shift = r2val.low; | |
1817 | if (code == RSHIFT_EXPR) | |
1818 | shift = -shift; | |
1819 | /* We need to know if we are doing a left or a right shift | |
1820 | to properly shift in zeros for left shift and unsigned | |
1821 | right shifts and the sign bit for signed right shifts. | |
1822 | For signed right shifts we shift in varying in case | |
1823 | the sign bit was varying. */ | |
1824 | if (shift > 0) | |
1825 | { | |
1826 | *mask = double_int_lshift (r1mask, shift, | |
1827 | TYPE_PRECISION (type), false); | |
1828 | *val = double_int_lshift (r1val, shift, | |
1829 | TYPE_PRECISION (type), false); | |
1830 | } | |
1831 | else if (shift < 0) | |
1832 | { | |
1833 | shift = -shift; | |
1834 | *mask = double_int_rshift (r1mask, shift, | |
1835 | TYPE_PRECISION (type), !uns); | |
1836 | *val = double_int_rshift (r1val, shift, | |
1837 | TYPE_PRECISION (type), !uns); | |
1838 | } | |
1839 | else | |
1840 | { | |
1841 | *mask = r1mask; | |
1842 | *val = r1val; | |
1843 | } | |
1844 | } | |
1845 | break; | |
1846 | ||
1847 | case PLUS_EXPR: | |
1848 | case POINTER_PLUS_EXPR: | |
1849 | { | |
1850 | double_int lo, hi; | |
1851 | /* Do the addition with unknown bits set to zero, to give carry-ins of | |
1852 | zero wherever possible. */ | |
1853 | lo = double_int_add (double_int_and_not (r1val, r1mask), | |
1854 | double_int_and_not (r2val, r2mask)); | |
1855 | lo = double_int_ext (lo, TYPE_PRECISION (type), uns); | |
1856 | /* Do the addition with unknown bits set to one, to give carry-ins of | |
1857 | one wherever possible. */ | |
1858 | hi = double_int_add (double_int_ior (r1val, r1mask), | |
1859 | double_int_ior (r2val, r2mask)); | |
1860 | hi = double_int_ext (hi, TYPE_PRECISION (type), uns); | |
1861 | /* Each bit in the result is known if (a) the corresponding bits in | |
1862 | both inputs are known, and (b) the carry-in to that bit position | |
1863 | is known. We can check condition (b) by seeing if we got the same | |
1864 | result with minimised carries as with maximised carries. */ | |
1865 | *mask = double_int_ior (double_int_ior (r1mask, r2mask), | |
1866 | double_int_xor (lo, hi)); | |
1867 | *mask = double_int_ext (*mask, TYPE_PRECISION (type), uns); | |
1868 | /* It shouldn't matter whether we choose lo or hi here. */ | |
1869 | *val = lo; | |
1870 | break; | |
1871 | } | |
1872 | ||
1873 | case MINUS_EXPR: | |
1874 | { | |
1875 | double_int temv, temm; | |
1876 | bit_value_unop_1 (NEGATE_EXPR, r2type, &temv, &temm, | |
1877 | r2type, r2val, r2mask); | |
1878 | bit_value_binop_1 (PLUS_EXPR, type, val, mask, | |
1879 | r1type, r1val, r1mask, | |
1880 | r2type, temv, temm); | |
1881 | break; | |
1882 | } | |
1883 | ||
1884 | case MULT_EXPR: | |
1885 | { | |
1886 | /* Just track trailing zeros in both operands and transfer | |
1887 | them to the other. */ | |
1888 | int r1tz = double_int_ctz (double_int_ior (r1val, r1mask)); | |
1889 | int r2tz = double_int_ctz (double_int_ior (r2val, r2mask)); | |
1890 | if (r1tz + r2tz >= HOST_BITS_PER_DOUBLE_INT) | |
1891 | { | |
1892 | *mask = double_int_zero; | |
1893 | *val = double_int_zero; | |
1894 | } | |
1895 | else if (r1tz + r2tz > 0) | |
1896 | { | |
1897 | *mask = double_int_not (double_int_mask (r1tz + r2tz)); | |
1898 | *mask = double_int_ext (*mask, TYPE_PRECISION (type), uns); | |
1899 | *val = double_int_zero; | |
1900 | } | |
1901 | break; | |
1902 | } | |
1903 | ||
1904 | case EQ_EXPR: | |
1905 | case NE_EXPR: | |
1906 | { | |
1907 | double_int m = double_int_ior (r1mask, r2mask); | |
1908 | if (!double_int_equal_p (double_int_and_not (r1val, m), | |
1909 | double_int_and_not (r2val, m))) | |
1910 | { | |
1911 | *mask = double_int_zero; | |
1912 | *val = ((code == EQ_EXPR) ? double_int_zero : double_int_one); | |
1913 | } | |
1914 | else | |
1915 | { | |
1916 | /* We know the result of a comparison is always one or zero. */ | |
1917 | *mask = double_int_one; | |
1918 | *val = double_int_zero; | |
1919 | } | |
1920 | break; | |
1921 | } | |
1922 | ||
1923 | case GE_EXPR: | |
1924 | case GT_EXPR: | |
1925 | { | |
1926 | double_int tem = r1val; | |
1927 | r1val = r2val; | |
1928 | r2val = tem; | |
1929 | tem = r1mask; | |
1930 | r1mask = r2mask; | |
1931 | r2mask = tem; | |
1932 | code = swap_tree_comparison (code); | |
1933 | } | |
1934 | /* Fallthru. */ | |
1935 | case LT_EXPR: | |
1936 | case LE_EXPR: | |
1937 | { | |
1938 | int minmax, maxmin; | |
1939 | /* If the most significant bits are not known we know nothing. */ | |
1940 | if (double_int_negative_p (r1mask) || double_int_negative_p (r2mask)) | |
1941 | break; | |
1942 | ||
1943 | /* If we know the most significant bits we know the values | |
1944 | value ranges by means of treating varying bits as zero | |
1945 | or one. Do a cross comparison of the max/min pairs. */ | |
1946 | maxmin = double_int_cmp (double_int_ior (r1val, r1mask), | |
1947 | double_int_and_not (r2val, r2mask), uns); | |
1948 | minmax = double_int_cmp (double_int_and_not (r1val, r1mask), | |
1949 | double_int_ior (r2val, r2mask), uns); | |
1950 | if (maxmin < 0) /* r1 is less than r2. */ | |
1951 | { | |
1952 | *mask = double_int_zero; | |
1953 | *val = double_int_one; | |
1954 | } | |
1955 | else if (minmax > 0) /* r1 is not less or equal to r2. */ | |
1956 | { | |
1957 | *mask = double_int_zero; | |
1958 | *val = double_int_zero; | |
1959 | } | |
1960 | else if (maxmin == minmax) /* r1 and r2 are equal. */ | |
1961 | { | |
1962 | /* This probably should never happen as we'd have | |
1963 | folded the thing during fully constant value folding. */ | |
1964 | *mask = double_int_zero; | |
1965 | *val = (code == LE_EXPR ? double_int_one : double_int_zero); | |
1966 | } | |
1967 | else | |
1968 | { | |
1969 | /* We know the result of a comparison is always one or zero. */ | |
1970 | *mask = double_int_one; | |
1971 | *val = double_int_zero; | |
1972 | } | |
1973 | break; | |
1974 | } | |
1975 | ||
1976 | default:; | |
1977 | } | |
1978 | } | |
1979 | ||
1980 | /* Return the propagation value when applying the operation CODE to | |
1981 | the value RHS yielding type TYPE. */ | |
1982 | ||
1983 | static prop_value_t | |
1984 | bit_value_unop (enum tree_code code, tree type, tree rhs) | |
1985 | { | |
1986 | prop_value_t rval = get_value_for_expr (rhs, true); | |
1987 | double_int value, mask; | |
1988 | prop_value_t val; | |
1989 | gcc_assert ((rval.lattice_val == CONSTANT | |
1990 | && TREE_CODE (rval.value) == INTEGER_CST) | |
1991 | || double_int_minus_one_p (rval.mask)); | |
1992 | bit_value_unop_1 (code, type, &value, &mask, | |
1993 | TREE_TYPE (rhs), value_to_double_int (rval), rval.mask); | |
1994 | if (!double_int_minus_one_p (mask)) | |
1995 | { | |
1996 | val.lattice_val = CONSTANT; | |
1997 | val.mask = mask; | |
1998 | /* ??? Delay building trees here. */ | |
1999 | val.value = double_int_to_tree (type, value); | |
2000 | } | |
2001 | else | |
2002 | { | |
2003 | val.lattice_val = VARYING; | |
2004 | val.value = NULL_TREE; | |
2005 | val.mask = double_int_minus_one; | |
2006 | } | |
2007 | return val; | |
2008 | } | |
2009 | ||
2010 | /* Return the propagation value when applying the operation CODE to | |
2011 | the values RHS1 and RHS2 yielding type TYPE. */ | |
2012 | ||
2013 | static prop_value_t | |
2014 | bit_value_binop (enum tree_code code, tree type, tree rhs1, tree rhs2) | |
2015 | { | |
2016 | prop_value_t r1val = get_value_for_expr (rhs1, true); | |
2017 | prop_value_t r2val = get_value_for_expr (rhs2, true); | |
2018 | double_int value, mask; | |
2019 | prop_value_t val; | |
2020 | gcc_assert ((r1val.lattice_val == CONSTANT | |
2021 | && TREE_CODE (r1val.value) == INTEGER_CST) | |
2022 | || double_int_minus_one_p (r1val.mask)); | |
2023 | gcc_assert ((r2val.lattice_val == CONSTANT | |
2024 | && TREE_CODE (r2val.value) == INTEGER_CST) | |
2025 | || double_int_minus_one_p (r2val.mask)); | |
2026 | bit_value_binop_1 (code, type, &value, &mask, | |
2027 | TREE_TYPE (rhs1), value_to_double_int (r1val), r1val.mask, | |
2028 | TREE_TYPE (rhs2), value_to_double_int (r2val), r2val.mask); | |
2029 | if (!double_int_minus_one_p (mask)) | |
2030 | { | |
2031 | val.lattice_val = CONSTANT; | |
2032 | val.mask = mask; | |
2033 | /* ??? Delay building trees here. */ | |
2034 | val.value = double_int_to_tree (type, value); | |
2035 | } | |
2036 | else | |
2037 | { | |
2038 | val.lattice_val = VARYING; | |
2039 | val.value = NULL_TREE; | |
2040 | val.mask = double_int_minus_one; | |
2041 | } | |
2042 | return val; | |
2043 | } | |
2044 | ||
726a989a RB |
2045 | /* Evaluate statement STMT. |
2046 | Valid only for assignments, calls, conditionals, and switches. */ | |
6de9cd9a | 2047 | |
0bca51f0 | 2048 | static prop_value_t |
726a989a | 2049 | evaluate_stmt (gimple stmt) |
6de9cd9a | 2050 | { |
0bca51f0 | 2051 | prop_value_t val; |
faaf1436 | 2052 | tree simplified = NULL_TREE; |
0bca51f0 | 2053 | ccp_lattice_t likelyvalue = likely_value (stmt); |
0b4b14ac | 2054 | bool is_constant = false; |
0bca51f0 | 2055 | |
0b4b14ac RG |
2056 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2057 | { | |
2058 | fprintf (dump_file, "which is likely "); | |
2059 | switch (likelyvalue) | |
2060 | { | |
2061 | case CONSTANT: | |
2062 | fprintf (dump_file, "CONSTANT"); | |
2063 | break; | |
2064 | case UNDEFINED: | |
2065 | fprintf (dump_file, "UNDEFINED"); | |
2066 | break; | |
2067 | case VARYING: | |
2068 | fprintf (dump_file, "VARYING"); | |
2069 | break; | |
2070 | default:; | |
2071 | } | |
2072 | fprintf (dump_file, "\n"); | |
2073 | } | |
6ac01510 | 2074 | |
6de9cd9a DN |
2075 | /* If the statement is likely to have a CONSTANT result, then try |
2076 | to fold the statement to determine the constant value. */ | |
726a989a RB |
2077 | /* FIXME. This is the only place that we call ccp_fold. |
2078 | Since likely_value never returns CONSTANT for calls, we will | |
2079 | not attempt to fold them, including builtins that may profit. */ | |
6de9cd9a | 2080 | if (likelyvalue == CONSTANT) |
0b4b14ac RG |
2081 | { |
2082 | fold_defer_overflow_warnings (); | |
2083 | simplified = ccp_fold (stmt); | |
2084 | is_constant = simplified && is_gimple_min_invariant (simplified); | |
2085 | fold_undefer_overflow_warnings (is_constant, stmt, 0); | |
2086 | if (is_constant) | |
2087 | { | |
2088 | /* The statement produced a constant value. */ | |
2089 | val.lattice_val = CONSTANT; | |
2090 | val.value = simplified; | |
2091 | val.mask = double_int_zero; | |
2092 | } | |
2093 | } | |
6de9cd9a DN |
2094 | /* If the statement is likely to have a VARYING result, then do not |
2095 | bother folding the statement. */ | |
87e1e42b | 2096 | else if (likelyvalue == VARYING) |
726a989a | 2097 | { |
e0c68ce9 | 2098 | enum gimple_code code = gimple_code (stmt); |
726a989a RB |
2099 | if (code == GIMPLE_ASSIGN) |
2100 | { | |
2101 | enum tree_code subcode = gimple_assign_rhs_code (stmt); | |
b8698a0f | 2102 | |
726a989a RB |
2103 | /* Other cases cannot satisfy is_gimple_min_invariant |
2104 | without folding. */ | |
2105 | if (get_gimple_rhs_class (subcode) == GIMPLE_SINGLE_RHS) | |
2106 | simplified = gimple_assign_rhs1 (stmt); | |
2107 | } | |
2108 | else if (code == GIMPLE_SWITCH) | |
2109 | simplified = gimple_switch_index (stmt); | |
2110 | else | |
44e10129 MM |
2111 | /* These cannot satisfy is_gimple_min_invariant without folding. */ |
2112 | gcc_assert (code == GIMPLE_CALL || code == GIMPLE_COND); | |
0b4b14ac RG |
2113 | is_constant = simplified && is_gimple_min_invariant (simplified); |
2114 | if (is_constant) | |
2115 | { | |
2116 | /* The statement produced a constant value. */ | |
2117 | val.lattice_val = CONSTANT; | |
2118 | val.value = simplified; | |
2119 | val.mask = double_int_zero; | |
2120 | } | |
726a989a | 2121 | } |
6de9cd9a | 2122 | |
0b4b14ac RG |
2123 | /* Resort to simplification for bitwise tracking. */ |
2124 | if (flag_tree_bit_ccp | |
2125 | && likelyvalue == CONSTANT | |
2126 | && !is_constant) | |
00d382a8 | 2127 | { |
0b4b14ac | 2128 | enum gimple_code code = gimple_code (stmt); |
1be38ccb | 2129 | tree fndecl; |
0b4b14ac RG |
2130 | val.lattice_val = VARYING; |
2131 | val.value = NULL_TREE; | |
2132 | val.mask = double_int_minus_one; | |
2133 | if (code == GIMPLE_ASSIGN) | |
00d382a8 | 2134 | { |
0b4b14ac RG |
2135 | enum tree_code subcode = gimple_assign_rhs_code (stmt); |
2136 | tree rhs1 = gimple_assign_rhs1 (stmt); | |
2137 | switch (get_gimple_rhs_class (subcode)) | |
2138 | { | |
2139 | case GIMPLE_SINGLE_RHS: | |
2140 | if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
2141 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
2142 | val = get_value_for_expr (rhs1, true); | |
2143 | break; | |
2144 | ||
2145 | case GIMPLE_UNARY_RHS: | |
2146 | if ((INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
2147 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
2148 | && (INTEGRAL_TYPE_P (gimple_expr_type (stmt)) | |
2149 | || POINTER_TYPE_P (gimple_expr_type (stmt)))) | |
2150 | val = bit_value_unop (subcode, gimple_expr_type (stmt), rhs1); | |
2151 | break; | |
2152 | ||
2153 | case GIMPLE_BINARY_RHS: | |
2154 | if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
2155 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
2156 | { | |
2157 | tree rhs2 = gimple_assign_rhs2 (stmt); | |
2158 | val = bit_value_binop (subcode, | |
2159 | TREE_TYPE (rhs1), rhs1, rhs2); | |
2160 | } | |
2161 | break; | |
2162 | ||
2163 | default:; | |
2164 | } | |
00d382a8 | 2165 | } |
0b4b14ac RG |
2166 | else if (code == GIMPLE_COND) |
2167 | { | |
2168 | enum tree_code code = gimple_cond_code (stmt); | |
2169 | tree rhs1 = gimple_cond_lhs (stmt); | |
2170 | tree rhs2 = gimple_cond_rhs (stmt); | |
2171 | if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
2172 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
2173 | val = bit_value_binop (code, TREE_TYPE (rhs1), rhs1, rhs2); | |
2174 | } | |
1be38ccb RG |
2175 | else if (code == GIMPLE_CALL |
2176 | && (fndecl = gimple_call_fndecl (stmt)) | |
2177 | && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL) | |
2178 | { | |
2179 | switch (DECL_FUNCTION_CODE (fndecl)) | |
2180 | { | |
2181 | case BUILT_IN_MALLOC: | |
2182 | case BUILT_IN_REALLOC: | |
2183 | case BUILT_IN_CALLOC: | |
2184 | val.lattice_val = CONSTANT; | |
2185 | val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0); | |
2186 | val.mask = shwi_to_double_int | |
2187 | (~(((HOST_WIDE_INT) MALLOC_ABI_ALIGNMENT) | |
2188 | / BITS_PER_UNIT - 1)); | |
2189 | break; | |
2190 | ||
2191 | case BUILT_IN_ALLOCA: | |
2192 | val.lattice_val = CONSTANT; | |
2193 | val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0); | |
2194 | val.mask = shwi_to_double_int | |
2195 | (~(((HOST_WIDE_INT) BIGGEST_ALIGNMENT) | |
2196 | / BITS_PER_UNIT - 1)); | |
2197 | break; | |
2198 | ||
2199 | default:; | |
2200 | } | |
2201 | } | |
0b4b14ac | 2202 | is_constant = (val.lattice_val == CONSTANT); |
00d382a8 RG |
2203 | } |
2204 | ||
0b4b14ac | 2205 | if (!is_constant) |
6de9cd9a DN |
2206 | { |
2207 | /* The statement produced a nonconstant value. If the statement | |
0bca51f0 DN |
2208 | had UNDEFINED operands, then the result of the statement |
2209 | should be UNDEFINED. Otherwise, the statement is VARYING. */ | |
106dec71 | 2210 | if (likelyvalue == UNDEFINED) |
0b4b14ac RG |
2211 | { |
2212 | val.lattice_val = likelyvalue; | |
2213 | val.mask = double_int_zero; | |
2214 | } | |
a318e3ac | 2215 | else |
0b4b14ac RG |
2216 | { |
2217 | val.lattice_val = VARYING; | |
2218 | val.mask = double_int_minus_one; | |
2219 | } | |
a318e3ac | 2220 | |
0bca51f0 | 2221 | val.value = NULL_TREE; |
6de9cd9a | 2222 | } |
750628d8 DN |
2223 | |
2224 | return val; | |
6de9cd9a DN |
2225 | } |
2226 | ||
f61e18ec RG |
2227 | /* Fold the stmt at *GSI with CCP specific information that propagating |
2228 | and regular folding does not catch. */ | |
2229 | ||
2230 | static bool | |
2231 | ccp_fold_stmt (gimple_stmt_iterator *gsi) | |
2232 | { | |
2233 | gimple stmt = gsi_stmt (*gsi); | |
f61e18ec | 2234 | |
830bc550 RG |
2235 | switch (gimple_code (stmt)) |
2236 | { | |
2237 | case GIMPLE_COND: | |
2238 | { | |
2239 | prop_value_t val; | |
2240 | /* Statement evaluation will handle type mismatches in constants | |
2241 | more gracefully than the final propagation. This allows us to | |
2242 | fold more conditionals here. */ | |
2243 | val = evaluate_stmt (stmt); | |
2244 | if (val.lattice_val != CONSTANT | |
0b4b14ac | 2245 | || !double_int_zero_p (val.mask)) |
830bc550 RG |
2246 | return false; |
2247 | ||
0b4b14ac RG |
2248 | if (dump_file) |
2249 | { | |
2250 | fprintf (dump_file, "Folding predicate "); | |
2251 | print_gimple_expr (dump_file, stmt, 0, 0); | |
2252 | fprintf (dump_file, " to "); | |
2253 | print_generic_expr (dump_file, val.value, 0); | |
2254 | fprintf (dump_file, "\n"); | |
2255 | } | |
2256 | ||
830bc550 RG |
2257 | if (integer_zerop (val.value)) |
2258 | gimple_cond_make_false (stmt); | |
2259 | else | |
2260 | gimple_cond_make_true (stmt); | |
f61e18ec | 2261 | |
830bc550 RG |
2262 | return true; |
2263 | } | |
f61e18ec | 2264 | |
830bc550 RG |
2265 | case GIMPLE_CALL: |
2266 | { | |
2267 | tree lhs = gimple_call_lhs (stmt); | |
84d77ca6 | 2268 | tree val; |
830bc550 | 2269 | tree argt; |
74e80a24 | 2270 | tree callee; |
830bc550 RG |
2271 | bool changed = false; |
2272 | unsigned i; | |
2273 | ||
2274 | /* If the call was folded into a constant make sure it goes | |
2275 | away even if we cannot propagate into all uses because of | |
2276 | type issues. */ | |
2277 | if (lhs | |
2278 | && TREE_CODE (lhs) == SSA_NAME | |
84d77ca6 | 2279 | && (val = get_constant_value (lhs))) |
830bc550 | 2280 | { |
84d77ca6 | 2281 | tree new_rhs = unshare_expr (val); |
eb6b98c7 | 2282 | bool res; |
830bc550 RG |
2283 | if (!useless_type_conversion_p (TREE_TYPE (lhs), |
2284 | TREE_TYPE (new_rhs))) | |
2285 | new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs); | |
eb6b98c7 RG |
2286 | res = update_call_from_tree (gsi, new_rhs); |
2287 | gcc_assert (res); | |
830bc550 RG |
2288 | return true; |
2289 | } | |
2290 | ||
2291 | /* Propagate into the call arguments. Compared to replace_uses_in | |
2292 | this can use the argument slot types for type verification | |
2293 | instead of the current argument type. We also can safely | |
2294 | drop qualifiers here as we are dealing with constants anyway. */ | |
2295 | argt = TYPE_ARG_TYPES (TREE_TYPE (TREE_TYPE (gimple_call_fn (stmt)))); | |
2296 | for (i = 0; i < gimple_call_num_args (stmt) && argt; | |
2297 | ++i, argt = TREE_CHAIN (argt)) | |
2298 | { | |
2299 | tree arg = gimple_call_arg (stmt, i); | |
2300 | if (TREE_CODE (arg) == SSA_NAME | |
84d77ca6 | 2301 | && (val = get_constant_value (arg)) |
830bc550 RG |
2302 | && useless_type_conversion_p |
2303 | (TYPE_MAIN_VARIANT (TREE_VALUE (argt)), | |
84d77ca6 | 2304 | TYPE_MAIN_VARIANT (TREE_TYPE (val)))) |
830bc550 | 2305 | { |
84d77ca6 | 2306 | gimple_call_set_arg (stmt, i, unshare_expr (val)); |
830bc550 RG |
2307 | changed = true; |
2308 | } | |
2309 | } | |
74e80a24 RG |
2310 | |
2311 | callee = gimple_call_fn (stmt); | |
2312 | if (TREE_CODE (callee) == OBJ_TYPE_REF | |
2313 | && TREE_CODE (OBJ_TYPE_REF_EXPR (callee)) == SSA_NAME) | |
31ceb574 | 2314 | { |
74e80a24 RG |
2315 | tree expr = OBJ_TYPE_REF_EXPR (callee); |
2316 | OBJ_TYPE_REF_EXPR (callee) = valueize_op (expr); | |
2317 | if (TREE_CODE (OBJ_TYPE_REF_EXPR (callee)) == ADDR_EXPR) | |
2318 | { | |
2319 | tree t; | |
2320 | t = gimple_fold_obj_type_ref (callee, NULL_TREE); | |
2321 | if (t) | |
2322 | { | |
2323 | gimple_call_set_fn (stmt, t); | |
2324 | changed = true; | |
2325 | } | |
2326 | } | |
2327 | OBJ_TYPE_REF_EXPR (callee) = expr; | |
31ceb574 | 2328 | } |
830bc550 RG |
2329 | |
2330 | return changed; | |
2331 | } | |
f61e18ec | 2332 | |
5c95f07b RG |
2333 | case GIMPLE_ASSIGN: |
2334 | { | |
2335 | tree lhs = gimple_assign_lhs (stmt); | |
84d77ca6 | 2336 | tree val; |
5c95f07b RG |
2337 | |
2338 | /* If we have a load that turned out to be constant replace it | |
2339 | as we cannot propagate into all uses in all cases. */ | |
2340 | if (gimple_assign_single_p (stmt) | |
2341 | && TREE_CODE (lhs) == SSA_NAME | |
84d77ca6 | 2342 | && (val = get_constant_value (lhs))) |
5c95f07b | 2343 | { |
84d77ca6 | 2344 | tree rhs = unshare_expr (val); |
5c95f07b | 2345 | if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs))) |
70f34814 | 2346 | rhs = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), rhs); |
5c95f07b RG |
2347 | gimple_assign_set_rhs_from_tree (gsi, rhs); |
2348 | return true; | |
2349 | } | |
2350 | ||
2351 | return false; | |
2352 | } | |
2353 | ||
830bc550 RG |
2354 | default: |
2355 | return false; | |
2356 | } | |
f61e18ec RG |
2357 | } |
2358 | ||
750628d8 | 2359 | /* Visit the assignment statement STMT. Set the value of its LHS to the |
0bca51f0 DN |
2360 | value computed by the RHS and store LHS in *OUTPUT_P. If STMT |
2361 | creates virtual definitions, set the value of each new name to that | |
726a989a RB |
2362 | of the RHS (if we can derive a constant out of the RHS). |
2363 | Value-returning call statements also perform an assignment, and | |
2364 | are handled here. */ | |
6de9cd9a | 2365 | |
750628d8 | 2366 | static enum ssa_prop_result |
726a989a | 2367 | visit_assignment (gimple stmt, tree *output_p) |
6de9cd9a | 2368 | { |
0bca51f0 | 2369 | prop_value_t val; |
0bca51f0 | 2370 | enum ssa_prop_result retval; |
6de9cd9a | 2371 | |
726a989a | 2372 | tree lhs = gimple_get_lhs (stmt); |
6de9cd9a | 2373 | |
726a989a RB |
2374 | gcc_assert (gimple_code (stmt) != GIMPLE_CALL |
2375 | || gimple_call_lhs (stmt) != NULL_TREE); | |
2376 | ||
84d77ca6 RG |
2377 | if (gimple_assign_single_p (stmt) |
2378 | && gimple_assign_rhs_code (stmt) == SSA_NAME) | |
2379 | /* For a simple copy operation, we copy the lattice values. */ | |
2380 | val = *get_value (gimple_assign_rhs1 (stmt)); | |
750628d8 | 2381 | else |
726a989a RB |
2382 | /* Evaluate the statement, which could be |
2383 | either a GIMPLE_ASSIGN or a GIMPLE_CALL. */ | |
87e1e42b | 2384 | val = evaluate_stmt (stmt); |
6de9cd9a | 2385 | |
0bca51f0 | 2386 | retval = SSA_PROP_NOT_INTERESTING; |
6de9cd9a | 2387 | |
750628d8 | 2388 | /* Set the lattice value of the statement's output. */ |
0bca51f0 | 2389 | if (TREE_CODE (lhs) == SSA_NAME) |
6de9cd9a | 2390 | { |
0bca51f0 DN |
2391 | /* If STMT is an assignment to an SSA_NAME, we only have one |
2392 | value to set. */ | |
2393 | if (set_lattice_value (lhs, val)) | |
2394 | { | |
2395 | *output_p = lhs; | |
2396 | if (val.lattice_val == VARYING) | |
2397 | retval = SSA_PROP_VARYING; | |
2398 | else | |
2399 | retval = SSA_PROP_INTERESTING; | |
2400 | } | |
6de9cd9a | 2401 | } |
0bca51f0 DN |
2402 | |
2403 | return retval; | |
6de9cd9a DN |
2404 | } |
2405 | ||
6de9cd9a | 2406 | |
750628d8 DN |
2407 | /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING |
2408 | if it can determine which edge will be taken. Otherwise, return | |
2409 | SSA_PROP_VARYING. */ | |
2410 | ||
2411 | static enum ssa_prop_result | |
726a989a | 2412 | visit_cond_stmt (gimple stmt, edge *taken_edge_p) |
6de9cd9a | 2413 | { |
0bca51f0 | 2414 | prop_value_t val; |
750628d8 DN |
2415 | basic_block block; |
2416 | ||
726a989a | 2417 | block = gimple_bb (stmt); |
750628d8 | 2418 | val = evaluate_stmt (stmt); |
0b4b14ac RG |
2419 | if (val.lattice_val != CONSTANT |
2420 | || !double_int_zero_p (val.mask)) | |
2421 | return SSA_PROP_VARYING; | |
750628d8 DN |
2422 | |
2423 | /* Find which edge out of the conditional block will be taken and add it | |
2424 | to the worklist. If no single edge can be determined statically, | |
2425 | return SSA_PROP_VARYING to feed all the outgoing edges to the | |
2426 | propagation engine. */ | |
0b4b14ac | 2427 | *taken_edge_p = find_taken_edge (block, val.value); |
750628d8 DN |
2428 | if (*taken_edge_p) |
2429 | return SSA_PROP_INTERESTING; | |
2430 | else | |
2431 | return SSA_PROP_VARYING; | |
6de9cd9a DN |
2432 | } |
2433 | ||
6de9cd9a | 2434 | |
750628d8 DN |
2435 | /* Evaluate statement STMT. If the statement produces an output value and |
2436 | its evaluation changes the lattice value of its output, return | |
2437 | SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the | |
2438 | output value. | |
b8698a0f | 2439 | |
750628d8 DN |
2440 | If STMT is a conditional branch and we can determine its truth |
2441 | value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying | |
2442 | value, return SSA_PROP_VARYING. */ | |
6de9cd9a | 2443 | |
750628d8 | 2444 | static enum ssa_prop_result |
726a989a | 2445 | ccp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p) |
750628d8 | 2446 | { |
750628d8 DN |
2447 | tree def; |
2448 | ssa_op_iter iter; | |
6de9cd9a | 2449 | |
750628d8 | 2450 | if (dump_file && (dump_flags & TDF_DETAILS)) |
6de9cd9a | 2451 | { |
0bca51f0 | 2452 | fprintf (dump_file, "\nVisiting statement:\n"); |
726a989a | 2453 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
6de9cd9a | 2454 | } |
6de9cd9a | 2455 | |
726a989a | 2456 | switch (gimple_code (stmt)) |
6de9cd9a | 2457 | { |
726a989a RB |
2458 | case GIMPLE_ASSIGN: |
2459 | /* If the statement is an assignment that produces a single | |
2460 | output value, evaluate its RHS to see if the lattice value of | |
2461 | its output has changed. */ | |
2462 | return visit_assignment (stmt, output_p); | |
2463 | ||
2464 | case GIMPLE_CALL: | |
2465 | /* A value-returning call also performs an assignment. */ | |
2466 | if (gimple_call_lhs (stmt) != NULL_TREE) | |
2467 | return visit_assignment (stmt, output_p); | |
2468 | break; | |
2469 | ||
2470 | case GIMPLE_COND: | |
2471 | case GIMPLE_SWITCH: | |
2472 | /* If STMT is a conditional branch, see if we can determine | |
2473 | which branch will be taken. */ | |
2474 | /* FIXME. It appears that we should be able to optimize | |
2475 | computed GOTOs here as well. */ | |
2476 | return visit_cond_stmt (stmt, taken_edge_p); | |
2477 | ||
2478 | default: | |
2479 | break; | |
6de9cd9a | 2480 | } |
6de9cd9a | 2481 | |
750628d8 DN |
2482 | /* Any other kind of statement is not interesting for constant |
2483 | propagation and, therefore, not worth simulating. */ | |
750628d8 DN |
2484 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2485 | fprintf (dump_file, "No interesting values produced. Marked VARYING.\n"); | |
6de9cd9a | 2486 | |
750628d8 DN |
2487 | /* Definitions made by statements other than assignments to |
2488 | SSA_NAMEs represent unknown modifications to their outputs. | |
2489 | Mark them VARYING. */ | |
0bca51f0 DN |
2490 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) |
2491 | { | |
0b4b14ac | 2492 | prop_value_t v = { VARYING, NULL_TREE, { -1, (HOST_WIDE_INT) -1 } }; |
0bca51f0 DN |
2493 | set_lattice_value (def, v); |
2494 | } | |
6de9cd9a | 2495 | |
750628d8 DN |
2496 | return SSA_PROP_VARYING; |
2497 | } | |
6de9cd9a | 2498 | |
6de9cd9a | 2499 | |
0bca51f0 | 2500 | /* Main entry point for SSA Conditional Constant Propagation. */ |
750628d8 | 2501 | |
3253eafb | 2502 | static unsigned int |
dce2b2f6 | 2503 | do_ssa_ccp (void) |
750628d8 DN |
2504 | { |
2505 | ccp_initialize (); | |
2506 | ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node); | |
3253eafb | 2507 | if (ccp_finalize ()) |
706ca88e | 2508 | return (TODO_cleanup_cfg | TODO_update_ssa | TODO_remove_unused_locals); |
3253eafb JH |
2509 | else |
2510 | return 0; | |
6de9cd9a DN |
2511 | } |
2512 | ||
173b818d BB |
2513 | |
2514 | static bool | |
750628d8 | 2515 | gate_ccp (void) |
173b818d | 2516 | { |
750628d8 | 2517 | return flag_tree_ccp != 0; |
173b818d BB |
2518 | } |
2519 | ||
6de9cd9a | 2520 | |
b8698a0f | 2521 | struct gimple_opt_pass pass_ccp = |
750628d8 | 2522 | { |
8ddbbcae JH |
2523 | { |
2524 | GIMPLE_PASS, | |
750628d8 DN |
2525 | "ccp", /* name */ |
2526 | gate_ccp, /* gate */ | |
0bca51f0 | 2527 | do_ssa_ccp, /* execute */ |
750628d8 DN |
2528 | NULL, /* sub */ |
2529 | NULL, /* next */ | |
2530 | 0, /* static_pass_number */ | |
2531 | TV_TREE_CCP, /* tv_id */ | |
7faade0f | 2532 | PROP_cfg | PROP_ssa, /* properties_required */ |
750628d8 | 2533 | 0, /* properties_provided */ |
ae07b463 | 2534 | 0, /* properties_destroyed */ |
750628d8 | 2535 | 0, /* todo_flags_start */ |
3253eafb | 2536 | TODO_dump_func | TODO_verify_ssa |
8ddbbcae JH |
2537 | | TODO_verify_stmts | TODO_ggc_collect/* todo_flags_finish */ |
2538 | } | |
750628d8 | 2539 | }; |
6de9cd9a | 2540 | |
6de9cd9a | 2541 | |
726a989a | 2542 | |
cb8e078d JJ |
2543 | /* Try to optimize out __builtin_stack_restore. Optimize it out |
2544 | if there is another __builtin_stack_restore in the same basic | |
2545 | block and no calls or ASM_EXPRs are in between, or if this block's | |
2546 | only outgoing edge is to EXIT_BLOCK and there are no calls or | |
2547 | ASM_EXPRs after this __builtin_stack_restore. */ | |
2548 | ||
2549 | static tree | |
726a989a | 2550 | optimize_stack_restore (gimple_stmt_iterator i) |
cb8e078d | 2551 | { |
ff9d1adc RH |
2552 | tree callee; |
2553 | gimple stmt; | |
726a989a RB |
2554 | |
2555 | basic_block bb = gsi_bb (i); | |
2556 | gimple call = gsi_stmt (i); | |
cb8e078d | 2557 | |
726a989a RB |
2558 | if (gimple_code (call) != GIMPLE_CALL |
2559 | || gimple_call_num_args (call) != 1 | |
2560 | || TREE_CODE (gimple_call_arg (call, 0)) != SSA_NAME | |
2561 | || !POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call, 0)))) | |
cb8e078d JJ |
2562 | return NULL_TREE; |
2563 | ||
726a989a | 2564 | for (gsi_next (&i); !gsi_end_p (i); gsi_next (&i)) |
cb8e078d | 2565 | { |
726a989a RB |
2566 | stmt = gsi_stmt (i); |
2567 | if (gimple_code (stmt) == GIMPLE_ASM) | |
cb8e078d | 2568 | return NULL_TREE; |
726a989a | 2569 | if (gimple_code (stmt) != GIMPLE_CALL) |
cb8e078d JJ |
2570 | continue; |
2571 | ||
726a989a | 2572 | callee = gimple_call_fndecl (stmt); |
12f9ddbc RG |
2573 | if (!callee |
2574 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL | |
2575 | /* All regular builtins are ok, just obviously not alloca. */ | |
2576 | || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA) | |
cb8e078d JJ |
2577 | return NULL_TREE; |
2578 | ||
2579 | if (DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_RESTORE) | |
ff9d1adc | 2580 | goto second_stack_restore; |
cb8e078d JJ |
2581 | } |
2582 | ||
ff9d1adc | 2583 | if (!gsi_end_p (i)) |
cb8e078d JJ |
2584 | return NULL_TREE; |
2585 | ||
ff9d1adc RH |
2586 | /* Allow one successor of the exit block, or zero successors. */ |
2587 | switch (EDGE_COUNT (bb->succs)) | |
2588 | { | |
2589 | case 0: | |
2590 | break; | |
2591 | case 1: | |
2592 | if (single_succ_edge (bb)->dest != EXIT_BLOCK_PTR) | |
2593 | return NULL_TREE; | |
2594 | break; | |
2595 | default: | |
2596 | return NULL_TREE; | |
2597 | } | |
2598 | second_stack_restore: | |
cb8e078d | 2599 | |
ff9d1adc RH |
2600 | /* If there's exactly one use, then zap the call to __builtin_stack_save. |
2601 | If there are multiple uses, then the last one should remove the call. | |
2602 | In any case, whether the call to __builtin_stack_save can be removed | |
2603 | or not is irrelevant to removing the call to __builtin_stack_restore. */ | |
2604 | if (has_single_use (gimple_call_arg (call, 0))) | |
2605 | { | |
2606 | gimple stack_save = SSA_NAME_DEF_STMT (gimple_call_arg (call, 0)); | |
2607 | if (is_gimple_call (stack_save)) | |
2608 | { | |
2609 | callee = gimple_call_fndecl (stack_save); | |
2610 | if (callee | |
2611 | && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL | |
2612 | && DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_SAVE) | |
2613 | { | |
2614 | gimple_stmt_iterator stack_save_gsi; | |
2615 | tree rhs; | |
cb8e078d | 2616 | |
ff9d1adc RH |
2617 | stack_save_gsi = gsi_for_stmt (stack_save); |
2618 | rhs = build_int_cst (TREE_TYPE (gimple_call_arg (call, 0)), 0); | |
2619 | update_call_from_tree (&stack_save_gsi, rhs); | |
2620 | } | |
2621 | } | |
2622 | } | |
cb8e078d | 2623 | |
726a989a | 2624 | /* No effect, so the statement will be deleted. */ |
cb8e078d JJ |
2625 | return integer_zero_node; |
2626 | } | |
726a989a | 2627 | |
d7bd8aeb JJ |
2628 | /* If va_list type is a simple pointer and nothing special is needed, |
2629 | optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0), | |
2630 | __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple | |
2631 | pointer assignment. */ | |
2632 | ||
2633 | static tree | |
726a989a | 2634 | optimize_stdarg_builtin (gimple call) |
d7bd8aeb | 2635 | { |
35cbb299 | 2636 | tree callee, lhs, rhs, cfun_va_list; |
d7bd8aeb | 2637 | bool va_list_simple_ptr; |
db3927fb | 2638 | location_t loc = gimple_location (call); |
d7bd8aeb | 2639 | |
726a989a | 2640 | if (gimple_code (call) != GIMPLE_CALL) |
d7bd8aeb JJ |
2641 | return NULL_TREE; |
2642 | ||
726a989a | 2643 | callee = gimple_call_fndecl (call); |
35cbb299 KT |
2644 | |
2645 | cfun_va_list = targetm.fn_abi_va_list (callee); | |
2646 | va_list_simple_ptr = POINTER_TYPE_P (cfun_va_list) | |
2647 | && (TREE_TYPE (cfun_va_list) == void_type_node | |
2648 | || TREE_TYPE (cfun_va_list) == char_type_node); | |
2649 | ||
d7bd8aeb JJ |
2650 | switch (DECL_FUNCTION_CODE (callee)) |
2651 | { | |
2652 | case BUILT_IN_VA_START: | |
2653 | if (!va_list_simple_ptr | |
2654 | || targetm.expand_builtin_va_start != NULL | |
726a989a | 2655 | || built_in_decls[BUILT_IN_NEXT_ARG] == NULL) |
d7bd8aeb JJ |
2656 | return NULL_TREE; |
2657 | ||
726a989a | 2658 | if (gimple_call_num_args (call) != 2) |
d7bd8aeb JJ |
2659 | return NULL_TREE; |
2660 | ||
726a989a | 2661 | lhs = gimple_call_arg (call, 0); |
d7bd8aeb JJ |
2662 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) |
2663 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
35cbb299 | 2664 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
d7bd8aeb | 2665 | return NULL_TREE; |
b8698a0f | 2666 | |
db3927fb AH |
2667 | lhs = build_fold_indirect_ref_loc (loc, lhs); |
2668 | rhs = build_call_expr_loc (loc, built_in_decls[BUILT_IN_NEXT_ARG], | |
726a989a | 2669 | 1, integer_zero_node); |
db3927fb | 2670 | rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); |
d7bd8aeb JJ |
2671 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); |
2672 | ||
2673 | case BUILT_IN_VA_COPY: | |
2674 | if (!va_list_simple_ptr) | |
2675 | return NULL_TREE; | |
2676 | ||
726a989a | 2677 | if (gimple_call_num_args (call) != 2) |
d7bd8aeb JJ |
2678 | return NULL_TREE; |
2679 | ||
726a989a | 2680 | lhs = gimple_call_arg (call, 0); |
d7bd8aeb JJ |
2681 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) |
2682 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
35cbb299 | 2683 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
d7bd8aeb JJ |
2684 | return NULL_TREE; |
2685 | ||
db3927fb | 2686 | lhs = build_fold_indirect_ref_loc (loc, lhs); |
726a989a | 2687 | rhs = gimple_call_arg (call, 1); |
d7bd8aeb | 2688 | if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs)) |
35cbb299 | 2689 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
d7bd8aeb JJ |
2690 | return NULL_TREE; |
2691 | ||
db3927fb | 2692 | rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); |
d7bd8aeb JJ |
2693 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); |
2694 | ||
2695 | case BUILT_IN_VA_END: | |
726a989a | 2696 | /* No effect, so the statement will be deleted. */ |
d7bd8aeb JJ |
2697 | return integer_zero_node; |
2698 | ||
2699 | default: | |
2700 | gcc_unreachable (); | |
2701 | } | |
2702 | } | |
726a989a | 2703 | |
6de9cd9a DN |
2704 | /* A simple pass that attempts to fold all builtin functions. This pass |
2705 | is run after we've propagated as many constants as we can. */ | |
2706 | ||
c2924966 | 2707 | static unsigned int |
6de9cd9a DN |
2708 | execute_fold_all_builtins (void) |
2709 | { | |
a7d6ba24 | 2710 | bool cfg_changed = false; |
6de9cd9a | 2711 | basic_block bb; |
7b0e48fb | 2712 | unsigned int todoflags = 0; |
b8698a0f | 2713 | |
6de9cd9a DN |
2714 | FOR_EACH_BB (bb) |
2715 | { | |
726a989a RB |
2716 | gimple_stmt_iterator i; |
2717 | for (i = gsi_start_bb (bb); !gsi_end_p (i); ) | |
6de9cd9a | 2718 | { |
726a989a | 2719 | gimple stmt, old_stmt; |
6de9cd9a | 2720 | tree callee, result; |
10a0d495 | 2721 | enum built_in_function fcode; |
6de9cd9a | 2722 | |
726a989a RB |
2723 | stmt = gsi_stmt (i); |
2724 | ||
2725 | if (gimple_code (stmt) != GIMPLE_CALL) | |
10a0d495 | 2726 | { |
726a989a | 2727 | gsi_next (&i); |
10a0d495 JJ |
2728 | continue; |
2729 | } | |
726a989a | 2730 | callee = gimple_call_fndecl (stmt); |
6de9cd9a | 2731 | if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) |
10a0d495 | 2732 | { |
726a989a | 2733 | gsi_next (&i); |
10a0d495 JJ |
2734 | continue; |
2735 | } | |
2736 | fcode = DECL_FUNCTION_CODE (callee); | |
6de9cd9a | 2737 | |
cbdd87d4 | 2738 | result = gimple_fold_builtin (stmt); |
53a8f709 UB |
2739 | |
2740 | if (result) | |
726a989a | 2741 | gimple_remove_stmt_histograms (cfun, stmt); |
53a8f709 | 2742 | |
6de9cd9a DN |
2743 | if (!result) |
2744 | switch (DECL_FUNCTION_CODE (callee)) | |
2745 | { | |
2746 | case BUILT_IN_CONSTANT_P: | |
2747 | /* Resolve __builtin_constant_p. If it hasn't been | |
2748 | folded to integer_one_node by now, it's fairly | |
2749 | certain that the value simply isn't constant. */ | |
726a989a | 2750 | result = integer_zero_node; |
6de9cd9a DN |
2751 | break; |
2752 | ||
cb8e078d | 2753 | case BUILT_IN_STACK_RESTORE: |
726a989a | 2754 | result = optimize_stack_restore (i); |
d7bd8aeb JJ |
2755 | if (result) |
2756 | break; | |
726a989a | 2757 | gsi_next (&i); |
d7bd8aeb JJ |
2758 | continue; |
2759 | ||
2760 | case BUILT_IN_VA_START: | |
2761 | case BUILT_IN_VA_END: | |
2762 | case BUILT_IN_VA_COPY: | |
2763 | /* These shouldn't be folded before pass_stdarg. */ | |
726a989a | 2764 | result = optimize_stdarg_builtin (stmt); |
cb8e078d JJ |
2765 | if (result) |
2766 | break; | |
2767 | /* FALLTHRU */ | |
2768 | ||
6de9cd9a | 2769 | default: |
726a989a | 2770 | gsi_next (&i); |
6de9cd9a DN |
2771 | continue; |
2772 | } | |
2773 | ||
2774 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2775 | { | |
2776 | fprintf (dump_file, "Simplified\n "); | |
726a989a | 2777 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
6de9cd9a DN |
2778 | } |
2779 | ||
726a989a | 2780 | old_stmt = stmt; |
726a989a | 2781 | if (!update_call_from_tree (&i, result)) |
4bad83f5 RG |
2782 | { |
2783 | gimplify_and_update_call_from_tree (&i, result); | |
2784 | todoflags |= TODO_update_address_taken; | |
2785 | } | |
cfaab3a9 | 2786 | |
726a989a | 2787 | stmt = gsi_stmt (i); |
cff4e50d | 2788 | update_stmt (stmt); |
cfaab3a9 | 2789 | |
726a989a RB |
2790 | if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt) |
2791 | && gimple_purge_dead_eh_edges (bb)) | |
a7d6ba24 | 2792 | cfg_changed = true; |
6de9cd9a DN |
2793 | |
2794 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2795 | { | |
2796 | fprintf (dump_file, "to\n "); | |
726a989a | 2797 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
6de9cd9a DN |
2798 | fprintf (dump_file, "\n"); |
2799 | } | |
10a0d495 JJ |
2800 | |
2801 | /* Retry the same statement if it changed into another | |
2802 | builtin, there might be new opportunities now. */ | |
726a989a | 2803 | if (gimple_code (stmt) != GIMPLE_CALL) |
10a0d495 | 2804 | { |
726a989a | 2805 | gsi_next (&i); |
10a0d495 JJ |
2806 | continue; |
2807 | } | |
726a989a | 2808 | callee = gimple_call_fndecl (stmt); |
10a0d495 | 2809 | if (!callee |
726a989a | 2810 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL |
10a0d495 | 2811 | || DECL_FUNCTION_CODE (callee) == fcode) |
726a989a | 2812 | gsi_next (&i); |
6de9cd9a DN |
2813 | } |
2814 | } | |
b8698a0f | 2815 | |
a7d6ba24 | 2816 | /* Delete unreachable blocks. */ |
7b0e48fb DB |
2817 | if (cfg_changed) |
2818 | todoflags |= TODO_cleanup_cfg; | |
b8698a0f | 2819 | |
7b0e48fb | 2820 | return todoflags; |
6de9cd9a DN |
2821 | } |
2822 | ||
750628d8 | 2823 | |
b8698a0f | 2824 | struct gimple_opt_pass pass_fold_builtins = |
6de9cd9a | 2825 | { |
8ddbbcae JH |
2826 | { |
2827 | GIMPLE_PASS, | |
6de9cd9a DN |
2828 | "fab", /* name */ |
2829 | NULL, /* gate */ | |
2830 | execute_fold_all_builtins, /* execute */ | |
2831 | NULL, /* sub */ | |
2832 | NULL, /* next */ | |
2833 | 0, /* static_pass_number */ | |
7072a650 | 2834 | TV_NONE, /* tv_id */ |
7faade0f | 2835 | PROP_cfg | PROP_ssa, /* properties_required */ |
6de9cd9a DN |
2836 | 0, /* properties_provided */ |
2837 | 0, /* properties_destroyed */ | |
2838 | 0, /* todo_flags_start */ | |
b28b1600 JJ |
2839 | TODO_dump_func |
2840 | | TODO_verify_ssa | |
8ddbbcae JH |
2841 | | TODO_update_ssa /* todo_flags_finish */ |
2842 | } | |
6de9cd9a | 2843 | }; |