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6de9cd9a | 1 | /* Conditional constant propagation pass for the GNU compiler. |
1cdaa211 | 2 | Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, |
4c0c3228 | 3 | 2010, 2011 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" |
74fe548b | 134 | #include "dbgcnt.h" |
cfef45c8 | 135 | #include "gimple-fold.h" |
1fed1006 | 136 | #include "params.h" |
6de9cd9a DN |
137 | |
138 | ||
139 | /* Possible lattice values. */ | |
140 | typedef enum | |
141 | { | |
106dec71 | 142 | UNINITIALIZED, |
6de9cd9a DN |
143 | UNDEFINED, |
144 | CONSTANT, | |
145 | VARYING | |
0bca51f0 | 146 | } ccp_lattice_t; |
6de9cd9a | 147 | |
455e6d5b RG |
148 | struct prop_value_d { |
149 | /* Lattice value. */ | |
150 | ccp_lattice_t lattice_val; | |
151 | ||
152 | /* Propagated value. */ | |
153 | tree value; | |
0b4b14ac RG |
154 | |
155 | /* Mask that applies to the propagated value during CCP. For | |
156 | X with a CONSTANT lattice value X & ~mask == value & ~mask. */ | |
157 | double_int mask; | |
455e6d5b RG |
158 | }; |
159 | ||
160 | typedef struct prop_value_d prop_value_t; | |
161 | ||
0bca51f0 DN |
162 | /* Array of propagated constant values. After propagation, |
163 | CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If | |
164 | the constant is held in an SSA name representing a memory store | |
38635499 DN |
165 | (i.e., a VDEF), CONST_VAL[I].MEM_REF will contain the actual |
166 | memory reference used to store (i.e., the LHS of the assignment | |
167 | doing the store). */ | |
404f4351 | 168 | static prop_value_t *const_val; |
6de9cd9a | 169 | |
25e20805 | 170 | static void canonicalize_float_value (prop_value_t *); |
f61e18ec | 171 | static bool ccp_fold_stmt (gimple_stmt_iterator *); |
25e20805 | 172 | |
0bca51f0 | 173 | /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */ |
95eec0d6 DB |
174 | |
175 | static void | |
0bca51f0 | 176 | dump_lattice_value (FILE *outf, const char *prefix, prop_value_t val) |
95eec0d6 | 177 | { |
750628d8 | 178 | switch (val.lattice_val) |
95eec0d6 | 179 | { |
0bca51f0 DN |
180 | case UNINITIALIZED: |
181 | fprintf (outf, "%sUNINITIALIZED", prefix); | |
182 | break; | |
750628d8 DN |
183 | case UNDEFINED: |
184 | fprintf (outf, "%sUNDEFINED", prefix); | |
185 | break; | |
186 | case VARYING: | |
187 | fprintf (outf, "%sVARYING", prefix); | |
188 | break; | |
750628d8 DN |
189 | case CONSTANT: |
190 | fprintf (outf, "%sCONSTANT ", prefix); | |
0b4b14ac RG |
191 | if (TREE_CODE (val.value) != INTEGER_CST |
192 | || double_int_zero_p (val.mask)) | |
193 | print_generic_expr (outf, val.value, dump_flags); | |
194 | else | |
195 | { | |
196 | double_int cval = double_int_and_not (tree_to_double_int (val.value), | |
197 | val.mask); | |
198 | fprintf (outf, "%sCONSTANT " HOST_WIDE_INT_PRINT_DOUBLE_HEX, | |
199 | prefix, cval.high, cval.low); | |
200 | fprintf (outf, " (" HOST_WIDE_INT_PRINT_DOUBLE_HEX ")", | |
201 | val.mask.high, val.mask.low); | |
202 | } | |
750628d8 DN |
203 | break; |
204 | default: | |
1e128c5f | 205 | gcc_unreachable (); |
750628d8 | 206 | } |
95eec0d6 | 207 | } |
6de9cd9a | 208 | |
6de9cd9a | 209 | |
0bca51f0 DN |
210 | /* Print lattice value VAL to stderr. */ |
211 | ||
212 | void debug_lattice_value (prop_value_t val); | |
213 | ||
24e47c76 | 214 | DEBUG_FUNCTION void |
0bca51f0 DN |
215 | debug_lattice_value (prop_value_t val) |
216 | { | |
217 | dump_lattice_value (stderr, "", val); | |
218 | fprintf (stderr, "\n"); | |
219 | } | |
6de9cd9a | 220 | |
6de9cd9a | 221 | |
0bca51f0 DN |
222 | /* Compute a default value for variable VAR and store it in the |
223 | CONST_VAL array. The following rules are used to get default | |
224 | values: | |
95eec0d6 | 225 | |
0bca51f0 DN |
226 | 1- Global and static variables that are declared constant are |
227 | considered CONSTANT. | |
228 | ||
229 | 2- Any other value is considered UNDEFINED. This is useful when | |
750628d8 DN |
230 | considering PHI nodes. PHI arguments that are undefined do not |
231 | change the constant value of the PHI node, which allows for more | |
0bca51f0 | 232 | constants to be propagated. |
6de9cd9a | 233 | |
caf55296 | 234 | 3- Variables defined by statements other than assignments and PHI |
0bca51f0 | 235 | nodes are considered VARYING. |
6de9cd9a | 236 | |
caf55296 | 237 | 4- Initial values of variables that are not GIMPLE registers are |
106dec71 | 238 | considered VARYING. */ |
6de9cd9a | 239 | |
0bca51f0 DN |
240 | static prop_value_t |
241 | get_default_value (tree var) | |
242 | { | |
243 | tree sym = SSA_NAME_VAR (var); | |
0b4b14ac | 244 | prop_value_t val = { UNINITIALIZED, NULL_TREE, { 0, 0 } }; |
e8114fba RG |
245 | gimple stmt; |
246 | ||
247 | stmt = SSA_NAME_DEF_STMT (var); | |
248 | ||
249 | if (gimple_nop_p (stmt)) | |
6de9cd9a | 250 | { |
e8114fba RG |
251 | /* Variables defined by an empty statement are those used |
252 | before being initialized. If VAR is a local variable, we | |
253 | can assume initially that it is UNDEFINED, otherwise we must | |
254 | consider it VARYING. */ | |
6938f93f JH |
255 | if (is_gimple_reg (sym) |
256 | && TREE_CODE (sym) == VAR_DECL) | |
e8114fba RG |
257 | val.lattice_val = UNDEFINED; |
258 | else | |
0b4b14ac RG |
259 | { |
260 | val.lattice_val = VARYING; | |
261 | val.mask = double_int_minus_one; | |
262 | } | |
6de9cd9a | 263 | } |
e8114fba RG |
264 | else if (is_gimple_assign (stmt) |
265 | /* Value-returning GIMPLE_CALL statements assign to | |
266 | a variable, and are treated similarly to GIMPLE_ASSIGN. */ | |
267 | || (is_gimple_call (stmt) | |
268 | && gimple_call_lhs (stmt) != NULL_TREE) | |
269 | || gimple_code (stmt) == GIMPLE_PHI) | |
750628d8 | 270 | { |
e8114fba RG |
271 | tree cst; |
272 | if (gimple_assign_single_p (stmt) | |
273 | && DECL_P (gimple_assign_rhs1 (stmt)) | |
274 | && (cst = get_symbol_constant_value (gimple_assign_rhs1 (stmt)))) | |
0bca51f0 | 275 | { |
e8114fba RG |
276 | val.lattice_val = CONSTANT; |
277 | val.value = cst; | |
0bca51f0 DN |
278 | } |
279 | else | |
e8114fba RG |
280 | /* Any other variable defined by an assignment or a PHI node |
281 | is considered UNDEFINED. */ | |
282 | val.lattice_val = UNDEFINED; | |
283 | } | |
284 | else | |
285 | { | |
286 | /* Otherwise, VAR will never take on a constant value. */ | |
287 | val.lattice_val = VARYING; | |
0b4b14ac | 288 | val.mask = double_int_minus_one; |
750628d8 | 289 | } |
6de9cd9a | 290 | |
750628d8 DN |
291 | return val; |
292 | } | |
6de9cd9a | 293 | |
6de9cd9a | 294 | |
106dec71 | 295 | /* Get the constant value associated with variable VAR. */ |
6de9cd9a | 296 | |
106dec71 ZD |
297 | static inline prop_value_t * |
298 | get_value (tree var) | |
0bca51f0 | 299 | { |
ed97ddc6 | 300 | prop_value_t *val; |
106dec71 | 301 | |
ed97ddc6 RG |
302 | if (const_val == NULL) |
303 | return NULL; | |
304 | ||
305 | val = &const_val[SSA_NAME_VERSION (var)]; | |
106dec71 | 306 | if (val->lattice_val == UNINITIALIZED) |
6de9cd9a DN |
307 | *val = get_default_value (var); |
308 | ||
25e20805 RG |
309 | canonicalize_float_value (val); |
310 | ||
6de9cd9a DN |
311 | return val; |
312 | } | |
313 | ||
84d77ca6 RG |
314 | /* Return the constant tree value associated with VAR. */ |
315 | ||
316 | static inline tree | |
317 | get_constant_value (tree var) | |
318 | { | |
e196b221 JH |
319 | prop_value_t *val; |
320 | if (TREE_CODE (var) != SSA_NAME) | |
321 | { | |
322 | if (is_gimple_min_invariant (var)) | |
323 | return var; | |
324 | return NULL_TREE; | |
325 | } | |
326 | val = get_value (var); | |
0b4b14ac RG |
327 | if (val |
328 | && val->lattice_val == CONSTANT | |
329 | && (TREE_CODE (val->value) != INTEGER_CST | |
330 | || double_int_zero_p (val->mask))) | |
84d77ca6 RG |
331 | return val->value; |
332 | return NULL_TREE; | |
333 | } | |
334 | ||
106dec71 ZD |
335 | /* Sets the value associated with VAR to VARYING. */ |
336 | ||
337 | static inline void | |
338 | set_value_varying (tree var) | |
339 | { | |
340 | prop_value_t *val = &const_val[SSA_NAME_VERSION (var)]; | |
341 | ||
342 | val->lattice_val = VARYING; | |
343 | val->value = NULL_TREE; | |
0b4b14ac | 344 | val->mask = double_int_minus_one; |
106dec71 | 345 | } |
6de9cd9a | 346 | |
fbb5445b L |
347 | /* For float types, modify the value of VAL to make ccp work correctly |
348 | for non-standard values (-0, NaN): | |
349 | ||
350 | If HONOR_SIGNED_ZEROS is false, and VAL = -0, we canonicalize it to 0. | |
351 | If HONOR_NANS is false, and VAL is NaN, we canonicalize it to UNDEFINED. | |
352 | This is to fix the following problem (see PR 29921): Suppose we have | |
353 | ||
354 | x = 0.0 * y | |
355 | ||
356 | and we set value of y to NaN. This causes value of x to be set to NaN. | |
357 | When we later determine that y is in fact VARYING, fold uses the fact | |
358 | that HONOR_NANS is false, and we try to change the value of x to 0, | |
359 | causing an ICE. With HONOR_NANS being false, the real appearance of | |
360 | NaN would cause undefined behavior, though, so claiming that y (and x) | |
361 | are UNDEFINED initially is correct. */ | |
362 | ||
363 | static void | |
364 | canonicalize_float_value (prop_value_t *val) | |
365 | { | |
366 | enum machine_mode mode; | |
367 | tree type; | |
368 | REAL_VALUE_TYPE d; | |
369 | ||
370 | if (val->lattice_val != CONSTANT | |
371 | || TREE_CODE (val->value) != REAL_CST) | |
372 | return; | |
373 | ||
374 | d = TREE_REAL_CST (val->value); | |
375 | type = TREE_TYPE (val->value); | |
376 | mode = TYPE_MODE (type); | |
377 | ||
378 | if (!HONOR_SIGNED_ZEROS (mode) | |
379 | && REAL_VALUE_MINUS_ZERO (d)) | |
380 | { | |
381 | val->value = build_real (type, dconst0); | |
382 | return; | |
383 | } | |
384 | ||
385 | if (!HONOR_NANS (mode) | |
386 | && REAL_VALUE_ISNAN (d)) | |
387 | { | |
388 | val->lattice_val = UNDEFINED; | |
389 | val->value = NULL; | |
fbb5445b L |
390 | return; |
391 | } | |
392 | } | |
393 | ||
0b4b14ac RG |
394 | /* Return whether the lattice transition is valid. */ |
395 | ||
396 | static bool | |
397 | valid_lattice_transition (prop_value_t old_val, prop_value_t new_val) | |
398 | { | |
399 | /* Lattice transitions must always be monotonically increasing in | |
400 | value. */ | |
401 | if (old_val.lattice_val < new_val.lattice_val) | |
402 | return true; | |
403 | ||
404 | if (old_val.lattice_val != new_val.lattice_val) | |
405 | return false; | |
406 | ||
407 | if (!old_val.value && !new_val.value) | |
408 | return true; | |
409 | ||
410 | /* Now both lattice values are CONSTANT. */ | |
411 | ||
412 | /* Allow transitioning from &x to &x & ~3. */ | |
413 | if (TREE_CODE (old_val.value) != INTEGER_CST | |
414 | && TREE_CODE (new_val.value) == INTEGER_CST) | |
415 | return true; | |
416 | ||
417 | /* Bit-lattices have to agree in the still valid bits. */ | |
418 | if (TREE_CODE (old_val.value) == INTEGER_CST | |
419 | && TREE_CODE (new_val.value) == INTEGER_CST) | |
420 | return double_int_equal_p | |
421 | (double_int_and_not (tree_to_double_int (old_val.value), | |
422 | new_val.mask), | |
423 | double_int_and_not (tree_to_double_int (new_val.value), | |
424 | new_val.mask)); | |
425 | ||
426 | /* Otherwise constant values have to agree. */ | |
427 | return operand_equal_p (old_val.value, new_val.value, 0); | |
428 | } | |
429 | ||
0bca51f0 DN |
430 | /* Set the value for variable VAR to NEW_VAL. Return true if the new |
431 | value is different from VAR's previous value. */ | |
6de9cd9a | 432 | |
750628d8 | 433 | static bool |
0bca51f0 | 434 | set_lattice_value (tree var, prop_value_t new_val) |
6de9cd9a | 435 | { |
7a95d078 RG |
436 | /* We can deal with old UNINITIALIZED values just fine here. */ |
437 | prop_value_t *old_val = &const_val[SSA_NAME_VERSION (var)]; | |
0bca51f0 | 438 | |
fbb5445b L |
439 | canonicalize_float_value (&new_val); |
440 | ||
0b4b14ac RG |
441 | /* We have to be careful to not go up the bitwise lattice |
442 | represented by the mask. | |
443 | ??? This doesn't seem to be the best place to enforce this. */ | |
444 | if (new_val.lattice_val == CONSTANT | |
445 | && old_val->lattice_val == CONSTANT | |
446 | && TREE_CODE (new_val.value) == INTEGER_CST | |
447 | && TREE_CODE (old_val->value) == INTEGER_CST) | |
448 | { | |
449 | double_int diff; | |
450 | diff = double_int_xor (tree_to_double_int (new_val.value), | |
451 | tree_to_double_int (old_val->value)); | |
452 | new_val.mask = double_int_ior (new_val.mask, | |
453 | double_int_ior (old_val->mask, diff)); | |
454 | } | |
106dec71 | 455 | |
0b4b14ac | 456 | gcc_assert (valid_lattice_transition (*old_val, new_val)); |
0bca51f0 | 457 | |
0b4b14ac RG |
458 | /* If *OLD_VAL and NEW_VAL are the same, return false to inform the |
459 | caller that this was a non-transition. */ | |
460 | if (old_val->lattice_val != new_val.lattice_val | |
461 | || (new_val.lattice_val == CONSTANT | |
462 | && TREE_CODE (new_val.value) == INTEGER_CST | |
463 | && (TREE_CODE (old_val->value) != INTEGER_CST | |
464 | || !double_int_equal_p (new_val.mask, old_val->mask)))) | |
6de9cd9a | 465 | { |
0b4b14ac RG |
466 | /* ??? We would like to delay creation of INTEGER_CSTs from |
467 | partially constants here. */ | |
468 | ||
750628d8 DN |
469 | if (dump_file && (dump_flags & TDF_DETAILS)) |
470 | { | |
0bca51f0 | 471 | dump_lattice_value (dump_file, "Lattice value changed to ", new_val); |
106dec71 | 472 | fprintf (dump_file, ". Adding SSA edges to worklist.\n"); |
750628d8 DN |
473 | } |
474 | ||
0bca51f0 DN |
475 | *old_val = new_val; |
476 | ||
7a95d078 | 477 | gcc_assert (new_val.lattice_val != UNINITIALIZED); |
106dec71 | 478 | return true; |
6de9cd9a | 479 | } |
750628d8 DN |
480 | |
481 | return false; | |
6de9cd9a DN |
482 | } |
483 | ||
0b4b14ac RG |
484 | static prop_value_t get_value_for_expr (tree, bool); |
485 | static prop_value_t bit_value_binop (enum tree_code, tree, tree, tree); | |
486 | static void bit_value_binop_1 (enum tree_code, tree, double_int *, double_int *, | |
487 | tree, double_int, double_int, | |
488 | tree, double_int, double_int); | |
489 | ||
490 | /* Return a double_int that can be used for bitwise simplifications | |
491 | from VAL. */ | |
492 | ||
493 | static double_int | |
494 | value_to_double_int (prop_value_t val) | |
495 | { | |
496 | if (val.value | |
497 | && TREE_CODE (val.value) == INTEGER_CST) | |
498 | return tree_to_double_int (val.value); | |
499 | else | |
500 | return double_int_zero; | |
501 | } | |
502 | ||
503 | /* Return the value for the address expression EXPR based on alignment | |
504 | information. */ | |
7a95d078 RG |
505 | |
506 | static prop_value_t | |
0b4b14ac RG |
507 | get_value_from_alignment (tree expr) |
508 | { | |
d1f4e15f | 509 | tree type = TREE_TYPE (expr); |
0b4b14ac | 510 | prop_value_t val; |
d1f4e15f RG |
511 | unsigned HOST_WIDE_INT bitpos; |
512 | unsigned int align; | |
0b4b14ac RG |
513 | |
514 | gcc_assert (TREE_CODE (expr) == ADDR_EXPR); | |
515 | ||
d1f4e15f RG |
516 | align = get_object_alignment_1 (TREE_OPERAND (expr, 0), &bitpos); |
517 | val.mask | |
518 | = double_int_and_not (POINTER_TYPE_P (type) || TYPE_UNSIGNED (type) | |
519 | ? double_int_mask (TYPE_PRECISION (type)) | |
520 | : double_int_minus_one, | |
521 | uhwi_to_double_int (align / BITS_PER_UNIT - 1)); | |
522 | val.lattice_val = double_int_minus_one_p (val.mask) ? VARYING : CONSTANT; | |
523 | if (val.lattice_val == CONSTANT) | |
524 | val.value | |
525 | = double_int_to_tree (type, uhwi_to_double_int (bitpos / BITS_PER_UNIT)); | |
0b4b14ac | 526 | else |
d1f4e15f | 527 | val.value = NULL_TREE; |
0b4b14ac RG |
528 | |
529 | return val; | |
530 | } | |
531 | ||
532 | /* Return the value for the tree operand EXPR. If FOR_BITS_P is true | |
533 | return constant bits extracted from alignment information for | |
534 | invariant addresses. */ | |
535 | ||
536 | static prop_value_t | |
537 | get_value_for_expr (tree expr, bool for_bits_p) | |
7a95d078 RG |
538 | { |
539 | prop_value_t val; | |
540 | ||
541 | if (TREE_CODE (expr) == SSA_NAME) | |
0b4b14ac RG |
542 | { |
543 | val = *get_value (expr); | |
544 | if (for_bits_p | |
545 | && val.lattice_val == CONSTANT | |
546 | && TREE_CODE (val.value) == ADDR_EXPR) | |
547 | val = get_value_from_alignment (val.value); | |
548 | } | |
549 | else if (is_gimple_min_invariant (expr) | |
550 | && (!for_bits_p || TREE_CODE (expr) != ADDR_EXPR)) | |
7a95d078 RG |
551 | { |
552 | val.lattice_val = CONSTANT; | |
553 | val.value = expr; | |
0b4b14ac | 554 | val.mask = double_int_zero; |
7a95d078 RG |
555 | canonicalize_float_value (&val); |
556 | } | |
0b4b14ac RG |
557 | else if (TREE_CODE (expr) == ADDR_EXPR) |
558 | val = get_value_from_alignment (expr); | |
7a95d078 RG |
559 | else |
560 | { | |
561 | val.lattice_val = VARYING; | |
0b4b14ac | 562 | val.mask = double_int_minus_one; |
7a95d078 RG |
563 | val.value = NULL_TREE; |
564 | } | |
7a95d078 RG |
565 | return val; |
566 | } | |
567 | ||
0bca51f0 | 568 | /* Return the likely CCP lattice value for STMT. |
6de9cd9a | 569 | |
750628d8 | 570 | If STMT has no operands, then return CONSTANT. |
6de9cd9a | 571 | |
7f879c96 RG |
572 | Else if undefinedness of operands of STMT cause its value to be |
573 | undefined, then return UNDEFINED. | |
6de9cd9a | 574 | |
750628d8 | 575 | Else if any operands of STMT are constants, then return CONSTANT. |
6de9cd9a | 576 | |
750628d8 | 577 | Else return VARYING. */ |
6de9cd9a | 578 | |
0bca51f0 | 579 | static ccp_lattice_t |
726a989a | 580 | likely_value (gimple stmt) |
750628d8 | 581 | { |
7f879c96 | 582 | bool has_constant_operand, has_undefined_operand, all_undefined_operands; |
750628d8 DN |
583 | tree use; |
584 | ssa_op_iter iter; | |
e8114fba | 585 | unsigned i; |
6de9cd9a | 586 | |
e0c68ce9 | 587 | enum gimple_code code = gimple_code (stmt); |
726a989a RB |
588 | |
589 | /* This function appears to be called only for assignments, calls, | |
590 | conditionals, and switches, due to the logic in visit_stmt. */ | |
591 | gcc_assert (code == GIMPLE_ASSIGN | |
592 | || code == GIMPLE_CALL | |
593 | || code == GIMPLE_COND | |
594 | || code == GIMPLE_SWITCH); | |
0bca51f0 DN |
595 | |
596 | /* If the statement has volatile operands, it won't fold to a | |
597 | constant value. */ | |
726a989a | 598 | if (gimple_has_volatile_ops (stmt)) |
0bca51f0 DN |
599 | return VARYING; |
600 | ||
726a989a | 601 | /* Arrive here for more complex cases. */ |
106dec71 | 602 | has_constant_operand = false; |
7f879c96 RG |
603 | has_undefined_operand = false; |
604 | all_undefined_operands = true; | |
e8114fba | 605 | FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE) |
750628d8 | 606 | { |
106dec71 | 607 | prop_value_t *val = get_value (use); |
750628d8 | 608 | |
106dec71 | 609 | if (val->lattice_val == UNDEFINED) |
7f879c96 RG |
610 | has_undefined_operand = true; |
611 | else | |
612 | all_undefined_operands = false; | |
0bca51f0 | 613 | |
750628d8 | 614 | if (val->lattice_val == CONSTANT) |
106dec71 | 615 | has_constant_operand = true; |
6de9cd9a | 616 | } |
750628d8 | 617 | |
5006671f RG |
618 | /* There may be constants in regular rhs operands. For calls we |
619 | have to ignore lhs, fndecl and static chain, otherwise only | |
620 | the lhs. */ | |
621 | for (i = (is_gimple_call (stmt) ? 2 : 0) + gimple_has_lhs (stmt); | |
e8114fba RG |
622 | i < gimple_num_ops (stmt); ++i) |
623 | { | |
624 | tree op = gimple_op (stmt, i); | |
625 | if (!op || TREE_CODE (op) == SSA_NAME) | |
626 | continue; | |
627 | if (is_gimple_min_invariant (op)) | |
628 | has_constant_operand = true; | |
629 | } | |
630 | ||
1cdaa211 RG |
631 | if (has_constant_operand) |
632 | all_undefined_operands = false; | |
633 | ||
7f879c96 RG |
634 | /* If the operation combines operands like COMPLEX_EXPR make sure to |
635 | not mark the result UNDEFINED if only one part of the result is | |
636 | undefined. */ | |
726a989a | 637 | if (has_undefined_operand && all_undefined_operands) |
7f879c96 | 638 | return UNDEFINED; |
726a989a | 639 | else if (code == GIMPLE_ASSIGN && has_undefined_operand) |
7f879c96 | 640 | { |
726a989a | 641 | switch (gimple_assign_rhs_code (stmt)) |
7f879c96 RG |
642 | { |
643 | /* Unary operators are handled with all_undefined_operands. */ | |
644 | case PLUS_EXPR: | |
645 | case MINUS_EXPR: | |
7f879c96 | 646 | case POINTER_PLUS_EXPR: |
7f879c96 RG |
647 | /* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected. |
648 | Not bitwise operators, one VARYING operand may specify the | |
649 | result completely. Not logical operators for the same reason. | |
0cedb9e9 RG |
650 | Not COMPLEX_EXPR as one VARYING operand makes the result partly |
651 | not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because | |
652 | the undefined operand may be promoted. */ | |
7f879c96 RG |
653 | return UNDEFINED; |
654 | ||
655 | default: | |
656 | ; | |
657 | } | |
658 | } | |
659 | /* If there was an UNDEFINED operand but the result may be not UNDEFINED | |
660 | fall back to VARYING even if there were CONSTANT operands. */ | |
661 | if (has_undefined_operand) | |
662 | return VARYING; | |
663 | ||
e8114fba RG |
664 | /* We do not consider virtual operands here -- load from read-only |
665 | memory may have only VARYING virtual operands, but still be | |
666 | constant. */ | |
106dec71 | 667 | if (has_constant_operand |
e8114fba | 668 | || gimple_references_memory_p (stmt)) |
0bca51f0 DN |
669 | return CONSTANT; |
670 | ||
106dec71 | 671 | return VARYING; |
6de9cd9a DN |
672 | } |
673 | ||
106dec71 ZD |
674 | /* Returns true if STMT cannot be constant. */ |
675 | ||
676 | static bool | |
726a989a | 677 | surely_varying_stmt_p (gimple stmt) |
106dec71 ZD |
678 | { |
679 | /* If the statement has operands that we cannot handle, it cannot be | |
680 | constant. */ | |
726a989a | 681 | if (gimple_has_volatile_ops (stmt)) |
106dec71 ZD |
682 | return true; |
683 | ||
174ef36d RG |
684 | /* If it is a call and does not return a value or is not a |
685 | builtin and not an indirect call, it is varying. */ | |
726a989a | 686 | if (is_gimple_call (stmt)) |
174ef36d RG |
687 | { |
688 | tree fndecl; | |
689 | if (!gimple_call_lhs (stmt) | |
690 | || ((fndecl = gimple_call_fndecl (stmt)) != NULL_TREE | |
99f536cc | 691 | && !DECL_BUILT_IN (fndecl))) |
174ef36d RG |
692 | return true; |
693 | } | |
106dec71 | 694 | |
e8114fba | 695 | /* Any other store operation is not interesting. */ |
5006671f | 696 | else if (gimple_vdef (stmt)) |
e8114fba RG |
697 | return true; |
698 | ||
106dec71 ZD |
699 | /* Anything other than assignments and conditional jumps are not |
700 | interesting for CCP. */ | |
726a989a | 701 | if (gimple_code (stmt) != GIMPLE_ASSIGN |
174ef36d RG |
702 | && gimple_code (stmt) != GIMPLE_COND |
703 | && gimple_code (stmt) != GIMPLE_SWITCH | |
704 | && gimple_code (stmt) != GIMPLE_CALL) | |
106dec71 ZD |
705 | return true; |
706 | ||
707 | return false; | |
708 | } | |
6de9cd9a | 709 | |
750628d8 | 710 | /* Initialize local data structures for CCP. */ |
6de9cd9a DN |
711 | |
712 | static void | |
750628d8 | 713 | ccp_initialize (void) |
6de9cd9a | 714 | { |
750628d8 | 715 | basic_block bb; |
6de9cd9a | 716 | |
b9eae1a9 | 717 | const_val = XCNEWVEC (prop_value_t, num_ssa_names); |
6de9cd9a | 718 | |
750628d8 DN |
719 | /* Initialize simulation flags for PHI nodes and statements. */ |
720 | FOR_EACH_BB (bb) | |
6de9cd9a | 721 | { |
726a989a | 722 | gimple_stmt_iterator i; |
6de9cd9a | 723 | |
726a989a | 724 | for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) |
750628d8 | 725 | { |
726a989a | 726 | gimple stmt = gsi_stmt (i); |
cd6ea7a2 RH |
727 | bool is_varying; |
728 | ||
729 | /* If the statement is a control insn, then we do not | |
730 | want to avoid simulating the statement once. Failure | |
731 | to do so means that those edges will never get added. */ | |
732 | if (stmt_ends_bb_p (stmt)) | |
733 | is_varying = false; | |
734 | else | |
735 | is_varying = surely_varying_stmt_p (stmt); | |
6de9cd9a | 736 | |
106dec71 | 737 | if (is_varying) |
750628d8 | 738 | { |
0bca51f0 DN |
739 | tree def; |
740 | ssa_op_iter iter; | |
741 | ||
742 | /* If the statement will not produce a constant, mark | |
743 | all its outputs VARYING. */ | |
744 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) | |
e8114fba | 745 | set_value_varying (def); |
750628d8 | 746 | } |
726a989a | 747 | prop_set_simulate_again (stmt, !is_varying); |
750628d8 | 748 | } |
6de9cd9a DN |
749 | } |
750 | ||
726a989a RB |
751 | /* Now process PHI nodes. We never clear the simulate_again flag on |
752 | phi nodes, since we do not know which edges are executable yet, | |
753 | except for phi nodes for virtual operands when we do not do store ccp. */ | |
750628d8 | 754 | FOR_EACH_BB (bb) |
6de9cd9a | 755 | { |
726a989a | 756 | gimple_stmt_iterator i; |
750628d8 | 757 | |
726a989a RB |
758 | for (i = gsi_start_phis (bb); !gsi_end_p (i); gsi_next (&i)) |
759 | { | |
760 | gimple phi = gsi_stmt (i); | |
761 | ||
dce2b2f6 | 762 | if (!is_gimple_reg (gimple_phi_result (phi))) |
726a989a | 763 | prop_set_simulate_again (phi, false); |
106dec71 | 764 | else |
726a989a | 765 | prop_set_simulate_again (phi, true); |
750628d8 | 766 | } |
6de9cd9a | 767 | } |
750628d8 | 768 | } |
6de9cd9a | 769 | |
74fe548b XDL |
770 | /* Debug count support. Reset the values of ssa names |
771 | VARYING when the total number ssa names analyzed is | |
772 | beyond the debug count specified. */ | |
773 | ||
774 | static void | |
775 | do_dbg_cnt (void) | |
776 | { | |
777 | unsigned i; | |
778 | for (i = 0; i < num_ssa_names; i++) | |
779 | { | |
780 | if (!dbg_cnt (ccp)) | |
781 | { | |
782 | const_val[i].lattice_val = VARYING; | |
0b4b14ac | 783 | const_val[i].mask = double_int_minus_one; |
74fe548b XDL |
784 | const_val[i].value = NULL_TREE; |
785 | } | |
786 | } | |
787 | } | |
788 | ||
6de9cd9a | 789 | |
0bca51f0 | 790 | /* Do final substitution of propagated values, cleanup the flowgraph and |
b8698a0f | 791 | free allocated storage. |
6de9cd9a | 792 | |
3253eafb JH |
793 | Return TRUE when something was optimized. */ |
794 | ||
795 | static bool | |
0bca51f0 | 796 | ccp_finalize (void) |
6de9cd9a | 797 | { |
74fe548b | 798 | bool something_changed; |
1be38ccb | 799 | unsigned i; |
74fe548b XDL |
800 | |
801 | do_dbg_cnt (); | |
1be38ccb RG |
802 | |
803 | /* Derive alignment and misalignment information from partially | |
804 | constant pointers in the lattice. */ | |
805 | for (i = 1; i < num_ssa_names; ++i) | |
806 | { | |
807 | tree name = ssa_name (i); | |
808 | prop_value_t *val; | |
809 | struct ptr_info_def *pi; | |
810 | unsigned int tem, align; | |
811 | ||
812 | if (!name | |
813 | || !POINTER_TYPE_P (TREE_TYPE (name))) | |
814 | continue; | |
815 | ||
816 | val = get_value (name); | |
817 | if (val->lattice_val != CONSTANT | |
818 | || TREE_CODE (val->value) != INTEGER_CST) | |
819 | continue; | |
820 | ||
821 | /* Trailing constant bits specify the alignment, trailing value | |
822 | bits the misalignment. */ | |
823 | tem = val->mask.low; | |
824 | align = (tem & -tem); | |
825 | if (align == 1) | |
826 | continue; | |
827 | ||
828 | pi = get_ptr_info (name); | |
829 | pi->align = align; | |
830 | pi->misalign = TREE_INT_CST_LOW (val->value) & (align - 1); | |
831 | } | |
832 | ||
0bca51f0 | 833 | /* Perform substitutions based on the known constant values. */ |
455e6d5b RG |
834 | something_changed = substitute_and_fold (get_constant_value, |
835 | ccp_fold_stmt, true); | |
6de9cd9a | 836 | |
0bca51f0 | 837 | free (const_val); |
ed97ddc6 | 838 | const_val = NULL; |
3253eafb | 839 | return something_changed;; |
6de9cd9a DN |
840 | } |
841 | ||
842 | ||
0bca51f0 DN |
843 | /* Compute the meet operator between *VAL1 and *VAL2. Store the result |
844 | in VAL1. | |
845 | ||
846 | any M UNDEFINED = any | |
0bca51f0 DN |
847 | any M VARYING = VARYING |
848 | Ci M Cj = Ci if (i == j) | |
849 | Ci M Cj = VARYING if (i != j) | |
106dec71 | 850 | */ |
6de9cd9a DN |
851 | |
852 | static void | |
0bca51f0 | 853 | ccp_lattice_meet (prop_value_t *val1, prop_value_t *val2) |
6de9cd9a | 854 | { |
0bca51f0 | 855 | if (val1->lattice_val == UNDEFINED) |
6de9cd9a | 856 | { |
0bca51f0 DN |
857 | /* UNDEFINED M any = any */ |
858 | *val1 = *val2; | |
750628d8 | 859 | } |
0bca51f0 | 860 | else if (val2->lattice_val == UNDEFINED) |
195da47b | 861 | { |
0bca51f0 DN |
862 | /* any M UNDEFINED = any |
863 | Nothing to do. VAL1 already contains the value we want. */ | |
864 | ; | |
195da47b | 865 | } |
0bca51f0 DN |
866 | else if (val1->lattice_val == VARYING |
867 | || val2->lattice_val == VARYING) | |
750628d8 | 868 | { |
0bca51f0 DN |
869 | /* any M VARYING = VARYING. */ |
870 | val1->lattice_val = VARYING; | |
0b4b14ac | 871 | val1->mask = double_int_minus_one; |
0bca51f0 | 872 | val1->value = NULL_TREE; |
750628d8 | 873 | } |
0b4b14ac RG |
874 | else if (val1->lattice_val == CONSTANT |
875 | && val2->lattice_val == CONSTANT | |
876 | && TREE_CODE (val1->value) == INTEGER_CST | |
877 | && TREE_CODE (val2->value) == INTEGER_CST) | |
878 | { | |
879 | /* Ci M Cj = Ci if (i == j) | |
880 | Ci M Cj = VARYING if (i != j) | |
881 | ||
882 | For INTEGER_CSTs mask unequal bits. If no equal bits remain, | |
883 | drop to varying. */ | |
884 | val1->mask | |
885 | = double_int_ior (double_int_ior (val1->mask, | |
886 | val2->mask), | |
887 | double_int_xor (tree_to_double_int (val1->value), | |
888 | tree_to_double_int (val2->value))); | |
889 | if (double_int_minus_one_p (val1->mask)) | |
890 | { | |
891 | val1->lattice_val = VARYING; | |
892 | val1->value = NULL_TREE; | |
893 | } | |
894 | } | |
0bca51f0 DN |
895 | else if (val1->lattice_val == CONSTANT |
896 | && val2->lattice_val == CONSTANT | |
dce2b2f6 | 897 | && simple_cst_equal (val1->value, val2->value) == 1) |
750628d8 | 898 | { |
0bca51f0 DN |
899 | /* Ci M Cj = Ci if (i == j) |
900 | Ci M Cj = VARYING if (i != j) | |
901 | ||
0b4b14ac RG |
902 | VAL1 already contains the value we want for equivalent values. */ |
903 | } | |
904 | else if (val1->lattice_val == CONSTANT | |
905 | && val2->lattice_val == CONSTANT | |
906 | && (TREE_CODE (val1->value) == ADDR_EXPR | |
907 | || TREE_CODE (val2->value) == ADDR_EXPR)) | |
908 | { | |
909 | /* When not equal addresses are involved try meeting for | |
910 | alignment. */ | |
911 | prop_value_t tem = *val2; | |
912 | if (TREE_CODE (val1->value) == ADDR_EXPR) | |
913 | *val1 = get_value_for_expr (val1->value, true); | |
914 | if (TREE_CODE (val2->value) == ADDR_EXPR) | |
915 | tem = get_value_for_expr (val2->value, true); | |
916 | ccp_lattice_meet (val1, &tem); | |
750628d8 DN |
917 | } |
918 | else | |
919 | { | |
0bca51f0 DN |
920 | /* Any other combination is VARYING. */ |
921 | val1->lattice_val = VARYING; | |
0b4b14ac | 922 | val1->mask = double_int_minus_one; |
0bca51f0 | 923 | val1->value = NULL_TREE; |
750628d8 | 924 | } |
6de9cd9a DN |
925 | } |
926 | ||
927 | ||
750628d8 DN |
928 | /* Loop through the PHI_NODE's parameters for BLOCK and compare their |
929 | lattice values to determine PHI_NODE's lattice value. The value of a | |
0bca51f0 | 930 | PHI node is determined calling ccp_lattice_meet with all the arguments |
750628d8 | 931 | of the PHI node that are incoming via executable edges. */ |
6de9cd9a | 932 | |
750628d8 | 933 | static enum ssa_prop_result |
726a989a | 934 | ccp_visit_phi_node (gimple phi) |
6de9cd9a | 935 | { |
726a989a | 936 | unsigned i; |
0bca51f0 | 937 | prop_value_t *old_val, new_val; |
6de9cd9a | 938 | |
750628d8 | 939 | if (dump_file && (dump_flags & TDF_DETAILS)) |
6de9cd9a | 940 | { |
750628d8 | 941 | fprintf (dump_file, "\nVisiting PHI node: "); |
726a989a | 942 | print_gimple_stmt (dump_file, phi, 0, dump_flags); |
6de9cd9a | 943 | } |
6de9cd9a | 944 | |
726a989a | 945 | old_val = get_value (gimple_phi_result (phi)); |
750628d8 DN |
946 | switch (old_val->lattice_val) |
947 | { | |
948 | case VARYING: | |
0bca51f0 | 949 | return SSA_PROP_VARYING; |
6de9cd9a | 950 | |
750628d8 DN |
951 | case CONSTANT: |
952 | new_val = *old_val; | |
953 | break; | |
6de9cd9a | 954 | |
750628d8 | 955 | case UNDEFINED: |
750628d8 | 956 | new_val.lattice_val = UNDEFINED; |
0bca51f0 | 957 | new_val.value = NULL_TREE; |
750628d8 | 958 | break; |
6de9cd9a | 959 | |
750628d8 | 960 | default: |
1e128c5f | 961 | gcc_unreachable (); |
750628d8 | 962 | } |
6de9cd9a | 963 | |
726a989a | 964 | for (i = 0; i < gimple_phi_num_args (phi); i++) |
750628d8 | 965 | { |
0bca51f0 DN |
966 | /* Compute the meet operator over all the PHI arguments flowing |
967 | through executable edges. */ | |
726a989a | 968 | edge e = gimple_phi_arg_edge (phi, i); |
6de9cd9a | 969 | |
750628d8 DN |
970 | if (dump_file && (dump_flags & TDF_DETAILS)) |
971 | { | |
972 | fprintf (dump_file, | |
973 | "\n Argument #%d (%d -> %d %sexecutable)\n", | |
974 | i, e->src->index, e->dest->index, | |
975 | (e->flags & EDGE_EXECUTABLE) ? "" : "not "); | |
976 | } | |
977 | ||
978 | /* If the incoming edge is executable, Compute the meet operator for | |
979 | the existing value of the PHI node and the current PHI argument. */ | |
980 | if (e->flags & EDGE_EXECUTABLE) | |
981 | { | |
726a989a | 982 | tree arg = gimple_phi_arg (phi, i)->def; |
0b4b14ac | 983 | prop_value_t arg_val = get_value_for_expr (arg, false); |
6de9cd9a | 984 | |
0bca51f0 | 985 | ccp_lattice_meet (&new_val, &arg_val); |
6de9cd9a | 986 | |
750628d8 DN |
987 | if (dump_file && (dump_flags & TDF_DETAILS)) |
988 | { | |
989 | fprintf (dump_file, "\t"); | |
0bca51f0 DN |
990 | print_generic_expr (dump_file, arg, dump_flags); |
991 | dump_lattice_value (dump_file, "\tValue: ", arg_val); | |
750628d8 DN |
992 | fprintf (dump_file, "\n"); |
993 | } | |
6de9cd9a | 994 | |
750628d8 DN |
995 | if (new_val.lattice_val == VARYING) |
996 | break; | |
997 | } | |
998 | } | |
6de9cd9a DN |
999 | |
1000 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
750628d8 DN |
1001 | { |
1002 | dump_lattice_value (dump_file, "\n PHI node value: ", new_val); | |
1003 | fprintf (dump_file, "\n\n"); | |
1004 | } | |
1005 | ||
106dec71 | 1006 | /* Make the transition to the new value. */ |
726a989a | 1007 | if (set_lattice_value (gimple_phi_result (phi), new_val)) |
750628d8 DN |
1008 | { |
1009 | if (new_val.lattice_val == VARYING) | |
1010 | return SSA_PROP_VARYING; | |
1011 | else | |
1012 | return SSA_PROP_INTERESTING; | |
1013 | } | |
1014 | else | |
1015 | return SSA_PROP_NOT_INTERESTING; | |
6de9cd9a DN |
1016 | } |
1017 | ||
84d77ca6 | 1018 | /* Return the constant value for OP or OP otherwise. */ |
0354c0c7 BS |
1019 | |
1020 | static tree | |
84d77ca6 | 1021 | valueize_op (tree op) |
0354c0c7 | 1022 | { |
0354c0c7 BS |
1023 | if (TREE_CODE (op) == SSA_NAME) |
1024 | { | |
84d77ca6 RG |
1025 | tree tem = get_constant_value (op); |
1026 | if (tem) | |
1027 | return tem; | |
0354c0c7 BS |
1028 | } |
1029 | return op; | |
1030 | } | |
1031 | ||
750628d8 DN |
1032 | /* CCP specific front-end to the non-destructive constant folding |
1033 | routines. | |
6de9cd9a DN |
1034 | |
1035 | Attempt to simplify the RHS of STMT knowing that one or more | |
1036 | operands are constants. | |
1037 | ||
1038 | If simplification is possible, return the simplified RHS, | |
726a989a | 1039 | otherwise return the original RHS or NULL_TREE. */ |
6de9cd9a DN |
1040 | |
1041 | static tree | |
726a989a | 1042 | ccp_fold (gimple stmt) |
6de9cd9a | 1043 | { |
db3927fb | 1044 | location_t loc = gimple_location (stmt); |
726a989a | 1045 | switch (gimple_code (stmt)) |
0bca51f0 | 1046 | { |
726a989a RB |
1047 | case GIMPLE_COND: |
1048 | { | |
1049 | /* Handle comparison operators that can appear in GIMPLE form. */ | |
84d77ca6 RG |
1050 | tree op0 = valueize_op (gimple_cond_lhs (stmt)); |
1051 | tree op1 = valueize_op (gimple_cond_rhs (stmt)); | |
726a989a | 1052 | enum tree_code code = gimple_cond_code (stmt); |
db3927fb | 1053 | return fold_binary_loc (loc, code, boolean_type_node, op0, op1); |
726a989a | 1054 | } |
6de9cd9a | 1055 | |
726a989a RB |
1056 | case GIMPLE_SWITCH: |
1057 | { | |
84d77ca6 RG |
1058 | /* Return the constant switch index. */ |
1059 | return valueize_op (gimple_switch_index (stmt)); | |
726a989a | 1060 | } |
00d382a8 | 1061 | |
cfef45c8 RG |
1062 | case GIMPLE_ASSIGN: |
1063 | case GIMPLE_CALL: | |
1064 | return gimple_fold_stmt_to_constant_1 (stmt, valueize_op); | |
87e1e42b | 1065 | |
ae3df618 | 1066 | default: |
cfef45c8 | 1067 | gcc_unreachable (); |
ae3df618 | 1068 | } |
ae3df618 | 1069 | } |
726a989a | 1070 | |
0b4b14ac RG |
1071 | /* Apply the operation CODE in type TYPE to the value, mask pair |
1072 | RVAL and RMASK representing a value of type RTYPE and set | |
1073 | the value, mask pair *VAL and *MASK to the result. */ | |
1074 | ||
1075 | static void | |
1076 | bit_value_unop_1 (enum tree_code code, tree type, | |
1077 | double_int *val, double_int *mask, | |
1078 | tree rtype, double_int rval, double_int rmask) | |
1079 | { | |
1080 | switch (code) | |
1081 | { | |
1082 | case BIT_NOT_EXPR: | |
1083 | *mask = rmask; | |
1084 | *val = double_int_not (rval); | |
1085 | break; | |
1086 | ||
1087 | case NEGATE_EXPR: | |
1088 | { | |
1089 | double_int temv, temm; | |
1090 | /* Return ~rval + 1. */ | |
1091 | bit_value_unop_1 (BIT_NOT_EXPR, type, &temv, &temm, type, rval, rmask); | |
1092 | bit_value_binop_1 (PLUS_EXPR, type, val, mask, | |
1093 | type, temv, temm, | |
1094 | type, double_int_one, double_int_zero); | |
1095 | break; | |
1096 | } | |
1097 | ||
1098 | CASE_CONVERT: | |
1099 | { | |
1100 | bool uns; | |
1101 | ||
1102 | /* First extend mask and value according to the original type. */ | |
1103 | uns = (TREE_CODE (rtype) == INTEGER_TYPE && TYPE_IS_SIZETYPE (rtype) | |
1104 | ? 0 : TYPE_UNSIGNED (rtype)); | |
1105 | *mask = double_int_ext (rmask, TYPE_PRECISION (rtype), uns); | |
1106 | *val = double_int_ext (rval, TYPE_PRECISION (rtype), uns); | |
1107 | ||
1108 | /* Then extend mask and value according to the target type. */ | |
1109 | uns = (TREE_CODE (type) == INTEGER_TYPE && TYPE_IS_SIZETYPE (type) | |
1110 | ? 0 : TYPE_UNSIGNED (type)); | |
1111 | *mask = double_int_ext (*mask, TYPE_PRECISION (type), uns); | |
1112 | *val = double_int_ext (*val, TYPE_PRECISION (type), uns); | |
1113 | break; | |
1114 | } | |
1115 | ||
1116 | default: | |
1117 | *mask = double_int_minus_one; | |
1118 | break; | |
1119 | } | |
1120 | } | |
1121 | ||
1122 | /* Apply the operation CODE in type TYPE to the value, mask pairs | |
1123 | R1VAL, R1MASK and R2VAL, R2MASK representing a values of type R1TYPE | |
1124 | and R2TYPE and set the value, mask pair *VAL and *MASK to the result. */ | |
1125 | ||
1126 | static void | |
1127 | bit_value_binop_1 (enum tree_code code, tree type, | |
1128 | double_int *val, double_int *mask, | |
1129 | tree r1type, double_int r1val, double_int r1mask, | |
1130 | tree r2type, double_int r2val, double_int r2mask) | |
1131 | { | |
0425d6f5 JJ |
1132 | bool uns = (TREE_CODE (type) == INTEGER_TYPE |
1133 | && TYPE_IS_SIZETYPE (type) ? 0 : TYPE_UNSIGNED (type)); | |
0b4b14ac RG |
1134 | /* Assume we'll get a constant result. Use an initial varying value, |
1135 | we fall back to varying in the end if necessary. */ | |
1136 | *mask = double_int_minus_one; | |
1137 | switch (code) | |
1138 | { | |
1139 | case BIT_AND_EXPR: | |
1140 | /* The mask is constant where there is a known not | |
1141 | set bit, (m1 | m2) & ((v1 | m1) & (v2 | m2)) */ | |
1142 | *mask = double_int_and (double_int_ior (r1mask, r2mask), | |
1143 | double_int_and (double_int_ior (r1val, r1mask), | |
1144 | double_int_ior (r2val, r2mask))); | |
1145 | *val = double_int_and (r1val, r2val); | |
1146 | break; | |
1147 | ||
1148 | case BIT_IOR_EXPR: | |
1149 | /* The mask is constant where there is a known | |
1150 | set bit, (m1 | m2) & ~((v1 & ~m1) | (v2 & ~m2)). */ | |
1151 | *mask = double_int_and_not | |
1152 | (double_int_ior (r1mask, r2mask), | |
1153 | double_int_ior (double_int_and_not (r1val, r1mask), | |
1154 | double_int_and_not (r2val, r2mask))); | |
1155 | *val = double_int_ior (r1val, r2val); | |
1156 | break; | |
1157 | ||
1158 | case BIT_XOR_EXPR: | |
1159 | /* m1 | m2 */ | |
1160 | *mask = double_int_ior (r1mask, r2mask); | |
1161 | *val = double_int_xor (r1val, r2val); | |
1162 | break; | |
1163 | ||
1164 | case LROTATE_EXPR: | |
1165 | case RROTATE_EXPR: | |
1166 | if (double_int_zero_p (r2mask)) | |
1167 | { | |
1168 | HOST_WIDE_INT shift = r2val.low; | |
1169 | if (code == RROTATE_EXPR) | |
1170 | shift = -shift; | |
1171 | *mask = double_int_lrotate (r1mask, shift, TYPE_PRECISION (type)); | |
1172 | *val = double_int_lrotate (r1val, shift, TYPE_PRECISION (type)); | |
1173 | } | |
1174 | break; | |
1175 | ||
1176 | case LSHIFT_EXPR: | |
1177 | case RSHIFT_EXPR: | |
1178 | /* ??? We can handle partially known shift counts if we know | |
1179 | its sign. That way we can tell that (x << (y | 8)) & 255 | |
1180 | is zero. */ | |
1181 | if (double_int_zero_p (r2mask)) | |
1182 | { | |
1183 | HOST_WIDE_INT shift = r2val.low; | |
1184 | if (code == RSHIFT_EXPR) | |
1185 | shift = -shift; | |
1186 | /* We need to know if we are doing a left or a right shift | |
1187 | to properly shift in zeros for left shift and unsigned | |
1188 | right shifts and the sign bit for signed right shifts. | |
1189 | For signed right shifts we shift in varying in case | |
1190 | the sign bit was varying. */ | |
1191 | if (shift > 0) | |
1192 | { | |
1193 | *mask = double_int_lshift (r1mask, shift, | |
1194 | TYPE_PRECISION (type), false); | |
1195 | *val = double_int_lshift (r1val, shift, | |
1196 | TYPE_PRECISION (type), false); | |
1197 | } | |
1198 | else if (shift < 0) | |
1199 | { | |
0425d6f5 JJ |
1200 | /* ??? We can have sizetype related inconsistencies in |
1201 | the IL. */ | |
1202 | if ((TREE_CODE (r1type) == INTEGER_TYPE | |
1203 | && (TYPE_IS_SIZETYPE (r1type) | |
1204 | ? 0 : TYPE_UNSIGNED (r1type))) != uns) | |
1205 | break; | |
1206 | ||
0b4b14ac RG |
1207 | shift = -shift; |
1208 | *mask = double_int_rshift (r1mask, shift, | |
1209 | TYPE_PRECISION (type), !uns); | |
1210 | *val = double_int_rshift (r1val, shift, | |
1211 | TYPE_PRECISION (type), !uns); | |
1212 | } | |
1213 | else | |
1214 | { | |
1215 | *mask = r1mask; | |
1216 | *val = r1val; | |
1217 | } | |
1218 | } | |
1219 | break; | |
1220 | ||
1221 | case PLUS_EXPR: | |
1222 | case POINTER_PLUS_EXPR: | |
1223 | { | |
1224 | double_int lo, hi; | |
1225 | /* Do the addition with unknown bits set to zero, to give carry-ins of | |
1226 | zero wherever possible. */ | |
1227 | lo = double_int_add (double_int_and_not (r1val, r1mask), | |
1228 | double_int_and_not (r2val, r2mask)); | |
1229 | lo = double_int_ext (lo, TYPE_PRECISION (type), uns); | |
1230 | /* Do the addition with unknown bits set to one, to give carry-ins of | |
1231 | one wherever possible. */ | |
1232 | hi = double_int_add (double_int_ior (r1val, r1mask), | |
1233 | double_int_ior (r2val, r2mask)); | |
1234 | hi = double_int_ext (hi, TYPE_PRECISION (type), uns); | |
1235 | /* Each bit in the result is known if (a) the corresponding bits in | |
1236 | both inputs are known, and (b) the carry-in to that bit position | |
1237 | is known. We can check condition (b) by seeing if we got the same | |
1238 | result with minimised carries as with maximised carries. */ | |
1239 | *mask = double_int_ior (double_int_ior (r1mask, r2mask), | |
1240 | double_int_xor (lo, hi)); | |
1241 | *mask = double_int_ext (*mask, TYPE_PRECISION (type), uns); | |
1242 | /* It shouldn't matter whether we choose lo or hi here. */ | |
1243 | *val = lo; | |
1244 | break; | |
1245 | } | |
1246 | ||
1247 | case MINUS_EXPR: | |
1248 | { | |
1249 | double_int temv, temm; | |
1250 | bit_value_unop_1 (NEGATE_EXPR, r2type, &temv, &temm, | |
1251 | r2type, r2val, r2mask); | |
1252 | bit_value_binop_1 (PLUS_EXPR, type, val, mask, | |
1253 | r1type, r1val, r1mask, | |
1254 | r2type, temv, temm); | |
1255 | break; | |
1256 | } | |
1257 | ||
1258 | case MULT_EXPR: | |
1259 | { | |
1260 | /* Just track trailing zeros in both operands and transfer | |
1261 | them to the other. */ | |
1262 | int r1tz = double_int_ctz (double_int_ior (r1val, r1mask)); | |
1263 | int r2tz = double_int_ctz (double_int_ior (r2val, r2mask)); | |
1264 | if (r1tz + r2tz >= HOST_BITS_PER_DOUBLE_INT) | |
1265 | { | |
1266 | *mask = double_int_zero; | |
1267 | *val = double_int_zero; | |
1268 | } | |
1269 | else if (r1tz + r2tz > 0) | |
1270 | { | |
1271 | *mask = double_int_not (double_int_mask (r1tz + r2tz)); | |
1272 | *mask = double_int_ext (*mask, TYPE_PRECISION (type), uns); | |
1273 | *val = double_int_zero; | |
1274 | } | |
1275 | break; | |
1276 | } | |
1277 | ||
1278 | case EQ_EXPR: | |
1279 | case NE_EXPR: | |
1280 | { | |
1281 | double_int m = double_int_ior (r1mask, r2mask); | |
1282 | if (!double_int_equal_p (double_int_and_not (r1val, m), | |
1283 | double_int_and_not (r2val, m))) | |
1284 | { | |
1285 | *mask = double_int_zero; | |
1286 | *val = ((code == EQ_EXPR) ? double_int_zero : double_int_one); | |
1287 | } | |
1288 | else | |
1289 | { | |
1290 | /* We know the result of a comparison is always one or zero. */ | |
1291 | *mask = double_int_one; | |
1292 | *val = double_int_zero; | |
1293 | } | |
1294 | break; | |
1295 | } | |
1296 | ||
1297 | case GE_EXPR: | |
1298 | case GT_EXPR: | |
1299 | { | |
1300 | double_int tem = r1val; | |
1301 | r1val = r2val; | |
1302 | r2val = tem; | |
1303 | tem = r1mask; | |
1304 | r1mask = r2mask; | |
1305 | r2mask = tem; | |
1306 | code = swap_tree_comparison (code); | |
1307 | } | |
1308 | /* Fallthru. */ | |
1309 | case LT_EXPR: | |
1310 | case LE_EXPR: | |
1311 | { | |
1312 | int minmax, maxmin; | |
1313 | /* If the most significant bits are not known we know nothing. */ | |
1314 | if (double_int_negative_p (r1mask) || double_int_negative_p (r2mask)) | |
1315 | break; | |
1316 | ||
0425d6f5 JJ |
1317 | /* For comparisons the signedness is in the comparison operands. */ |
1318 | uns = (TREE_CODE (r1type) == INTEGER_TYPE | |
1319 | && TYPE_IS_SIZETYPE (r1type) ? 0 : TYPE_UNSIGNED (r1type)); | |
1320 | /* ??? We can have sizetype related inconsistencies in the IL. */ | |
1321 | if ((TREE_CODE (r2type) == INTEGER_TYPE | |
1322 | && TYPE_IS_SIZETYPE (r2type) ? 0 : TYPE_UNSIGNED (r2type)) != uns) | |
1323 | break; | |
1324 | ||
0b4b14ac RG |
1325 | /* If we know the most significant bits we know the values |
1326 | value ranges by means of treating varying bits as zero | |
1327 | or one. Do a cross comparison of the max/min pairs. */ | |
1328 | maxmin = double_int_cmp (double_int_ior (r1val, r1mask), | |
1329 | double_int_and_not (r2val, r2mask), uns); | |
1330 | minmax = double_int_cmp (double_int_and_not (r1val, r1mask), | |
1331 | double_int_ior (r2val, r2mask), uns); | |
1332 | if (maxmin < 0) /* r1 is less than r2. */ | |
1333 | { | |
1334 | *mask = double_int_zero; | |
1335 | *val = double_int_one; | |
1336 | } | |
1337 | else if (minmax > 0) /* r1 is not less or equal to r2. */ | |
1338 | { | |
1339 | *mask = double_int_zero; | |
1340 | *val = double_int_zero; | |
1341 | } | |
1342 | else if (maxmin == minmax) /* r1 and r2 are equal. */ | |
1343 | { | |
1344 | /* This probably should never happen as we'd have | |
1345 | folded the thing during fully constant value folding. */ | |
1346 | *mask = double_int_zero; | |
1347 | *val = (code == LE_EXPR ? double_int_one : double_int_zero); | |
1348 | } | |
1349 | else | |
1350 | { | |
1351 | /* We know the result of a comparison is always one or zero. */ | |
1352 | *mask = double_int_one; | |
1353 | *val = double_int_zero; | |
1354 | } | |
1355 | break; | |
1356 | } | |
1357 | ||
1358 | default:; | |
1359 | } | |
1360 | } | |
1361 | ||
1362 | /* Return the propagation value when applying the operation CODE to | |
1363 | the value RHS yielding type TYPE. */ | |
1364 | ||
1365 | static prop_value_t | |
1366 | bit_value_unop (enum tree_code code, tree type, tree rhs) | |
1367 | { | |
1368 | prop_value_t rval = get_value_for_expr (rhs, true); | |
1369 | double_int value, mask; | |
1370 | prop_value_t val; | |
1371 | gcc_assert ((rval.lattice_val == CONSTANT | |
1372 | && TREE_CODE (rval.value) == INTEGER_CST) | |
1373 | || double_int_minus_one_p (rval.mask)); | |
1374 | bit_value_unop_1 (code, type, &value, &mask, | |
1375 | TREE_TYPE (rhs), value_to_double_int (rval), rval.mask); | |
1376 | if (!double_int_minus_one_p (mask)) | |
1377 | { | |
1378 | val.lattice_val = CONSTANT; | |
1379 | val.mask = mask; | |
1380 | /* ??? Delay building trees here. */ | |
1381 | val.value = double_int_to_tree (type, value); | |
1382 | } | |
1383 | else | |
1384 | { | |
1385 | val.lattice_val = VARYING; | |
1386 | val.value = NULL_TREE; | |
1387 | val.mask = double_int_minus_one; | |
1388 | } | |
1389 | return val; | |
1390 | } | |
1391 | ||
1392 | /* Return the propagation value when applying the operation CODE to | |
1393 | the values RHS1 and RHS2 yielding type TYPE. */ | |
1394 | ||
1395 | static prop_value_t | |
1396 | bit_value_binop (enum tree_code code, tree type, tree rhs1, tree rhs2) | |
1397 | { | |
1398 | prop_value_t r1val = get_value_for_expr (rhs1, true); | |
1399 | prop_value_t r2val = get_value_for_expr (rhs2, true); | |
1400 | double_int value, mask; | |
1401 | prop_value_t val; | |
1402 | gcc_assert ((r1val.lattice_val == CONSTANT | |
1403 | && TREE_CODE (r1val.value) == INTEGER_CST) | |
1404 | || double_int_minus_one_p (r1val.mask)); | |
1405 | gcc_assert ((r2val.lattice_val == CONSTANT | |
1406 | && TREE_CODE (r2val.value) == INTEGER_CST) | |
1407 | || double_int_minus_one_p (r2val.mask)); | |
1408 | bit_value_binop_1 (code, type, &value, &mask, | |
1409 | TREE_TYPE (rhs1), value_to_double_int (r1val), r1val.mask, | |
1410 | TREE_TYPE (rhs2), value_to_double_int (r2val), r2val.mask); | |
1411 | if (!double_int_minus_one_p (mask)) | |
1412 | { | |
1413 | val.lattice_val = CONSTANT; | |
1414 | val.mask = mask; | |
1415 | /* ??? Delay building trees here. */ | |
1416 | val.value = double_int_to_tree (type, value); | |
1417 | } | |
1418 | else | |
1419 | { | |
1420 | val.lattice_val = VARYING; | |
1421 | val.value = NULL_TREE; | |
1422 | val.mask = double_int_minus_one; | |
1423 | } | |
1424 | return val; | |
1425 | } | |
1426 | ||
45d439ac JJ |
1427 | /* Return the propagation value when applying __builtin_assume_aligned to |
1428 | its arguments. */ | |
1429 | ||
1430 | static prop_value_t | |
1431 | bit_value_assume_aligned (gimple stmt) | |
1432 | { | |
1433 | tree ptr = gimple_call_arg (stmt, 0), align, misalign = NULL_TREE; | |
1434 | tree type = TREE_TYPE (ptr); | |
1435 | unsigned HOST_WIDE_INT aligni, misaligni = 0; | |
1436 | prop_value_t ptrval = get_value_for_expr (ptr, true); | |
1437 | prop_value_t alignval; | |
1438 | double_int value, mask; | |
1439 | prop_value_t val; | |
1440 | if (ptrval.lattice_val == UNDEFINED) | |
1441 | return ptrval; | |
1442 | gcc_assert ((ptrval.lattice_val == CONSTANT | |
1443 | && TREE_CODE (ptrval.value) == INTEGER_CST) | |
1444 | || double_int_minus_one_p (ptrval.mask)); | |
1445 | align = gimple_call_arg (stmt, 1); | |
1446 | if (!host_integerp (align, 1)) | |
1447 | return ptrval; | |
1448 | aligni = tree_low_cst (align, 1); | |
1449 | if (aligni <= 1 | |
1450 | || (aligni & (aligni - 1)) != 0) | |
1451 | return ptrval; | |
1452 | if (gimple_call_num_args (stmt) > 2) | |
1453 | { | |
1454 | misalign = gimple_call_arg (stmt, 2); | |
1455 | if (!host_integerp (misalign, 1)) | |
1456 | return ptrval; | |
1457 | misaligni = tree_low_cst (misalign, 1); | |
1458 | if (misaligni >= aligni) | |
1459 | return ptrval; | |
1460 | } | |
1461 | align = build_int_cst_type (type, -aligni); | |
1462 | alignval = get_value_for_expr (align, true); | |
1463 | bit_value_binop_1 (BIT_AND_EXPR, type, &value, &mask, | |
1464 | type, value_to_double_int (ptrval), ptrval.mask, | |
1465 | type, value_to_double_int (alignval), alignval.mask); | |
1466 | if (!double_int_minus_one_p (mask)) | |
1467 | { | |
1468 | val.lattice_val = CONSTANT; | |
1469 | val.mask = mask; | |
1470 | gcc_assert ((mask.low & (aligni - 1)) == 0); | |
1471 | gcc_assert ((value.low & (aligni - 1)) == 0); | |
1472 | value.low |= misaligni; | |
1473 | /* ??? Delay building trees here. */ | |
1474 | val.value = double_int_to_tree (type, value); | |
1475 | } | |
1476 | else | |
1477 | { | |
1478 | val.lattice_val = VARYING; | |
1479 | val.value = NULL_TREE; | |
1480 | val.mask = double_int_minus_one; | |
1481 | } | |
1482 | return val; | |
1483 | } | |
1484 | ||
726a989a RB |
1485 | /* Evaluate statement STMT. |
1486 | Valid only for assignments, calls, conditionals, and switches. */ | |
6de9cd9a | 1487 | |
0bca51f0 | 1488 | static prop_value_t |
726a989a | 1489 | evaluate_stmt (gimple stmt) |
6de9cd9a | 1490 | { |
0bca51f0 | 1491 | prop_value_t val; |
faaf1436 | 1492 | tree simplified = NULL_TREE; |
0bca51f0 | 1493 | ccp_lattice_t likelyvalue = likely_value (stmt); |
0b4b14ac | 1494 | bool is_constant = false; |
0bca51f0 | 1495 | |
0b4b14ac RG |
1496 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1497 | { | |
1498 | fprintf (dump_file, "which is likely "); | |
1499 | switch (likelyvalue) | |
1500 | { | |
1501 | case CONSTANT: | |
1502 | fprintf (dump_file, "CONSTANT"); | |
1503 | break; | |
1504 | case UNDEFINED: | |
1505 | fprintf (dump_file, "UNDEFINED"); | |
1506 | break; | |
1507 | case VARYING: | |
1508 | fprintf (dump_file, "VARYING"); | |
1509 | break; | |
1510 | default:; | |
1511 | } | |
1512 | fprintf (dump_file, "\n"); | |
1513 | } | |
6ac01510 | 1514 | |
6de9cd9a DN |
1515 | /* If the statement is likely to have a CONSTANT result, then try |
1516 | to fold the statement to determine the constant value. */ | |
726a989a RB |
1517 | /* FIXME. This is the only place that we call ccp_fold. |
1518 | Since likely_value never returns CONSTANT for calls, we will | |
1519 | not attempt to fold them, including builtins that may profit. */ | |
6de9cd9a | 1520 | if (likelyvalue == CONSTANT) |
0b4b14ac RG |
1521 | { |
1522 | fold_defer_overflow_warnings (); | |
1523 | simplified = ccp_fold (stmt); | |
1524 | is_constant = simplified && is_gimple_min_invariant (simplified); | |
1525 | fold_undefer_overflow_warnings (is_constant, stmt, 0); | |
1526 | if (is_constant) | |
1527 | { | |
1528 | /* The statement produced a constant value. */ | |
1529 | val.lattice_val = CONSTANT; | |
1530 | val.value = simplified; | |
1531 | val.mask = double_int_zero; | |
1532 | } | |
1533 | } | |
6de9cd9a DN |
1534 | /* If the statement is likely to have a VARYING result, then do not |
1535 | bother folding the statement. */ | |
87e1e42b | 1536 | else if (likelyvalue == VARYING) |
726a989a | 1537 | { |
e0c68ce9 | 1538 | enum gimple_code code = gimple_code (stmt); |
726a989a RB |
1539 | if (code == GIMPLE_ASSIGN) |
1540 | { | |
1541 | enum tree_code subcode = gimple_assign_rhs_code (stmt); | |
b8698a0f | 1542 | |
726a989a RB |
1543 | /* Other cases cannot satisfy is_gimple_min_invariant |
1544 | without folding. */ | |
1545 | if (get_gimple_rhs_class (subcode) == GIMPLE_SINGLE_RHS) | |
1546 | simplified = gimple_assign_rhs1 (stmt); | |
1547 | } | |
1548 | else if (code == GIMPLE_SWITCH) | |
1549 | simplified = gimple_switch_index (stmt); | |
1550 | else | |
44e10129 MM |
1551 | /* These cannot satisfy is_gimple_min_invariant without folding. */ |
1552 | gcc_assert (code == GIMPLE_CALL || code == GIMPLE_COND); | |
0b4b14ac RG |
1553 | is_constant = simplified && is_gimple_min_invariant (simplified); |
1554 | if (is_constant) | |
1555 | { | |
1556 | /* The statement produced a constant value. */ | |
1557 | val.lattice_val = CONSTANT; | |
1558 | val.value = simplified; | |
1559 | val.mask = double_int_zero; | |
1560 | } | |
726a989a | 1561 | } |
6de9cd9a | 1562 | |
0b4b14ac RG |
1563 | /* Resort to simplification for bitwise tracking. */ |
1564 | if (flag_tree_bit_ccp | |
36dc1a88 | 1565 | && (likelyvalue == CONSTANT || is_gimple_call (stmt)) |
0b4b14ac | 1566 | && !is_constant) |
00d382a8 | 1567 | { |
0b4b14ac | 1568 | enum gimple_code code = gimple_code (stmt); |
1be38ccb | 1569 | tree fndecl; |
0b4b14ac RG |
1570 | val.lattice_val = VARYING; |
1571 | val.value = NULL_TREE; | |
1572 | val.mask = double_int_minus_one; | |
1573 | if (code == GIMPLE_ASSIGN) | |
00d382a8 | 1574 | { |
0b4b14ac RG |
1575 | enum tree_code subcode = gimple_assign_rhs_code (stmt); |
1576 | tree rhs1 = gimple_assign_rhs1 (stmt); | |
1577 | switch (get_gimple_rhs_class (subcode)) | |
1578 | { | |
1579 | case GIMPLE_SINGLE_RHS: | |
1580 | if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
1581 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
1582 | val = get_value_for_expr (rhs1, true); | |
1583 | break; | |
1584 | ||
1585 | case GIMPLE_UNARY_RHS: | |
1586 | if ((INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
1587 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
1588 | && (INTEGRAL_TYPE_P (gimple_expr_type (stmt)) | |
1589 | || POINTER_TYPE_P (gimple_expr_type (stmt)))) | |
1590 | val = bit_value_unop (subcode, gimple_expr_type (stmt), rhs1); | |
1591 | break; | |
1592 | ||
1593 | case GIMPLE_BINARY_RHS: | |
1594 | if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
1595 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
1596 | { | |
4e996296 | 1597 | tree lhs = gimple_assign_lhs (stmt); |
0b4b14ac RG |
1598 | tree rhs2 = gimple_assign_rhs2 (stmt); |
1599 | val = bit_value_binop (subcode, | |
4e996296 | 1600 | TREE_TYPE (lhs), rhs1, rhs2); |
0b4b14ac RG |
1601 | } |
1602 | break; | |
1603 | ||
1604 | default:; | |
1605 | } | |
00d382a8 | 1606 | } |
0b4b14ac RG |
1607 | else if (code == GIMPLE_COND) |
1608 | { | |
1609 | enum tree_code code = gimple_cond_code (stmt); | |
1610 | tree rhs1 = gimple_cond_lhs (stmt); | |
1611 | tree rhs2 = gimple_cond_rhs (stmt); | |
1612 | if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) | |
1613 | || POINTER_TYPE_P (TREE_TYPE (rhs1))) | |
1614 | val = bit_value_binop (code, TREE_TYPE (rhs1), rhs1, rhs2); | |
1615 | } | |
1be38ccb RG |
1616 | else if (code == GIMPLE_CALL |
1617 | && (fndecl = gimple_call_fndecl (stmt)) | |
1618 | && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL) | |
1619 | { | |
1620 | switch (DECL_FUNCTION_CODE (fndecl)) | |
1621 | { | |
1622 | case BUILT_IN_MALLOC: | |
1623 | case BUILT_IN_REALLOC: | |
1624 | case BUILT_IN_CALLOC: | |
36dc1a88 JJ |
1625 | case BUILT_IN_STRDUP: |
1626 | case BUILT_IN_STRNDUP: | |
1be38ccb RG |
1627 | val.lattice_val = CONSTANT; |
1628 | val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0); | |
1629 | val.mask = shwi_to_double_int | |
1630 | (~(((HOST_WIDE_INT) MALLOC_ABI_ALIGNMENT) | |
1631 | / BITS_PER_UNIT - 1)); | |
1632 | break; | |
1633 | ||
1634 | case BUILT_IN_ALLOCA: | |
1635 | val.lattice_val = CONSTANT; | |
1636 | val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0); | |
1637 | val.mask = shwi_to_double_int | |
1638 | (~(((HOST_WIDE_INT) BIGGEST_ALIGNMENT) | |
1639 | / BITS_PER_UNIT - 1)); | |
1640 | break; | |
1641 | ||
36dc1a88 JJ |
1642 | /* These builtins return their first argument, unmodified. */ |
1643 | case BUILT_IN_MEMCPY: | |
1644 | case BUILT_IN_MEMMOVE: | |
1645 | case BUILT_IN_MEMSET: | |
1646 | case BUILT_IN_STRCPY: | |
1647 | case BUILT_IN_STRNCPY: | |
1648 | case BUILT_IN_MEMCPY_CHK: | |
1649 | case BUILT_IN_MEMMOVE_CHK: | |
1650 | case BUILT_IN_MEMSET_CHK: | |
1651 | case BUILT_IN_STRCPY_CHK: | |
1652 | case BUILT_IN_STRNCPY_CHK: | |
1653 | val = get_value_for_expr (gimple_call_arg (stmt, 0), true); | |
1654 | break; | |
1655 | ||
45d439ac JJ |
1656 | case BUILT_IN_ASSUME_ALIGNED: |
1657 | val = bit_value_assume_aligned (stmt); | |
1658 | break; | |
1659 | ||
1be38ccb RG |
1660 | default:; |
1661 | } | |
1662 | } | |
0b4b14ac | 1663 | is_constant = (val.lattice_val == CONSTANT); |
00d382a8 RG |
1664 | } |
1665 | ||
0b4b14ac | 1666 | if (!is_constant) |
6de9cd9a DN |
1667 | { |
1668 | /* The statement produced a nonconstant value. If the statement | |
0bca51f0 DN |
1669 | had UNDEFINED operands, then the result of the statement |
1670 | should be UNDEFINED. Otherwise, the statement is VARYING. */ | |
106dec71 | 1671 | if (likelyvalue == UNDEFINED) |
0b4b14ac RG |
1672 | { |
1673 | val.lattice_val = likelyvalue; | |
1674 | val.mask = double_int_zero; | |
1675 | } | |
a318e3ac | 1676 | else |
0b4b14ac RG |
1677 | { |
1678 | val.lattice_val = VARYING; | |
1679 | val.mask = double_int_minus_one; | |
1680 | } | |
a318e3ac | 1681 | |
0bca51f0 | 1682 | val.value = NULL_TREE; |
6de9cd9a | 1683 | } |
750628d8 DN |
1684 | |
1685 | return val; | |
6de9cd9a DN |
1686 | } |
1687 | ||
1fed1006 TV |
1688 | /* Detects a vla-related alloca with a constant argument. Declares fixed-size |
1689 | array and return the address, if found, otherwise returns NULL_TREE. */ | |
1690 | ||
1691 | static tree | |
1692 | fold_builtin_alloca_for_var (gimple stmt) | |
1693 | { | |
1694 | unsigned HOST_WIDE_INT size, threshold, n_elem; | |
1695 | tree lhs, arg, block, var, elem_type, array_type; | |
1696 | unsigned int align; | |
1697 | ||
1698 | /* Get lhs. */ | |
1699 | lhs = gimple_call_lhs (stmt); | |
1700 | if (lhs == NULL_TREE) | |
1701 | return NULL_TREE; | |
1702 | ||
1703 | /* Detect constant argument. */ | |
1704 | arg = get_constant_value (gimple_call_arg (stmt, 0)); | |
1705 | if (arg == NULL_TREE || TREE_CODE (arg) != INTEGER_CST | |
1706 | || !host_integerp (arg, 1)) | |
1707 | return NULL_TREE; | |
1708 | size = TREE_INT_CST_LOW (arg); | |
1709 | ||
1710 | /* Heuristic: don't fold large vlas. */ | |
1711 | threshold = (unsigned HOST_WIDE_INT)PARAM_VALUE (PARAM_LARGE_STACK_FRAME); | |
1712 | /* In case a vla is declared at function scope, it has the same lifetime as a | |
1713 | declared array, so we allow a larger size. */ | |
1714 | block = gimple_block (stmt); | |
1715 | if (!(cfun->after_inlining | |
1716 | && TREE_CODE (BLOCK_SUPERCONTEXT (block)) == FUNCTION_DECL)) | |
1717 | threshold /= 10; | |
1718 | if (size > threshold) | |
1719 | return NULL_TREE; | |
1720 | ||
1721 | /* Declare array. */ | |
1722 | elem_type = build_nonstandard_integer_type (BITS_PER_UNIT, 1); | |
1723 | n_elem = size * 8 / BITS_PER_UNIT; | |
1724 | align = MIN (size * 8, BIGGEST_ALIGNMENT); | |
1725 | array_type = build_array_type_nelts (elem_type, n_elem); | |
1726 | var = create_tmp_var (array_type, NULL); | |
1727 | DECL_ALIGN (var) = align; | |
1728 | ||
1729 | /* Fold alloca to the address of the array. */ | |
1730 | return fold_convert (TREE_TYPE (lhs), build_fold_addr_expr (var)); | |
1731 | } | |
1732 | ||
f61e18ec RG |
1733 | /* Fold the stmt at *GSI with CCP specific information that propagating |
1734 | and regular folding does not catch. */ | |
1735 | ||
1736 | static bool | |
1737 | ccp_fold_stmt (gimple_stmt_iterator *gsi) | |
1738 | { | |
1739 | gimple stmt = gsi_stmt (*gsi); | |
f61e18ec | 1740 | |
830bc550 RG |
1741 | switch (gimple_code (stmt)) |
1742 | { | |
1743 | case GIMPLE_COND: | |
1744 | { | |
1745 | prop_value_t val; | |
1746 | /* Statement evaluation will handle type mismatches in constants | |
1747 | more gracefully than the final propagation. This allows us to | |
1748 | fold more conditionals here. */ | |
1749 | val = evaluate_stmt (stmt); | |
1750 | if (val.lattice_val != CONSTANT | |
0b4b14ac | 1751 | || !double_int_zero_p (val.mask)) |
830bc550 RG |
1752 | return false; |
1753 | ||
0b4b14ac RG |
1754 | if (dump_file) |
1755 | { | |
1756 | fprintf (dump_file, "Folding predicate "); | |
1757 | print_gimple_expr (dump_file, stmt, 0, 0); | |
1758 | fprintf (dump_file, " to "); | |
1759 | print_generic_expr (dump_file, val.value, 0); | |
1760 | fprintf (dump_file, "\n"); | |
1761 | } | |
1762 | ||
830bc550 RG |
1763 | if (integer_zerop (val.value)) |
1764 | gimple_cond_make_false (stmt); | |
1765 | else | |
1766 | gimple_cond_make_true (stmt); | |
f61e18ec | 1767 | |
830bc550 RG |
1768 | return true; |
1769 | } | |
f61e18ec | 1770 | |
830bc550 RG |
1771 | case GIMPLE_CALL: |
1772 | { | |
1773 | tree lhs = gimple_call_lhs (stmt); | |
84d77ca6 | 1774 | tree val; |
830bc550 RG |
1775 | tree argt; |
1776 | bool changed = false; | |
1777 | unsigned i; | |
1778 | ||
1779 | /* If the call was folded into a constant make sure it goes | |
1780 | away even if we cannot propagate into all uses because of | |
1781 | type issues. */ | |
1782 | if (lhs | |
1783 | && TREE_CODE (lhs) == SSA_NAME | |
84d77ca6 | 1784 | && (val = get_constant_value (lhs))) |
830bc550 | 1785 | { |
84d77ca6 | 1786 | tree new_rhs = unshare_expr (val); |
eb6b98c7 | 1787 | bool res; |
830bc550 RG |
1788 | if (!useless_type_conversion_p (TREE_TYPE (lhs), |
1789 | TREE_TYPE (new_rhs))) | |
1790 | new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs); | |
eb6b98c7 RG |
1791 | res = update_call_from_tree (gsi, new_rhs); |
1792 | gcc_assert (res); | |
830bc550 RG |
1793 | return true; |
1794 | } | |
1795 | ||
25583c4f RS |
1796 | /* Internal calls provide no argument types, so the extra laxity |
1797 | for normal calls does not apply. */ | |
1798 | if (gimple_call_internal_p (stmt)) | |
1799 | return false; | |
1800 | ||
1fed1006 TV |
1801 | /* The heuristic of fold_builtin_alloca_for_var differs before and after |
1802 | inlining, so we don't require the arg to be changed into a constant | |
1803 | for folding, but just to be constant. */ | |
1804 | if (gimple_call_alloca_for_var_p (stmt)) | |
1805 | { | |
1806 | tree new_rhs = fold_builtin_alloca_for_var (stmt); | |
1807 | bool res; | |
1808 | if (new_rhs == NULL_TREE) | |
1809 | return false; | |
1810 | res = update_call_from_tree (gsi, new_rhs); | |
1811 | gcc_assert (res); | |
1812 | return true; | |
1813 | } | |
1814 | ||
830bc550 RG |
1815 | /* Propagate into the call arguments. Compared to replace_uses_in |
1816 | this can use the argument slot types for type verification | |
1817 | instead of the current argument type. We also can safely | |
1818 | drop qualifiers here as we are dealing with constants anyway. */ | |
9bfc434b | 1819 | argt = TYPE_ARG_TYPES (gimple_call_fntype (stmt)); |
830bc550 RG |
1820 | for (i = 0; i < gimple_call_num_args (stmt) && argt; |
1821 | ++i, argt = TREE_CHAIN (argt)) | |
1822 | { | |
1823 | tree arg = gimple_call_arg (stmt, i); | |
1824 | if (TREE_CODE (arg) == SSA_NAME | |
84d77ca6 | 1825 | && (val = get_constant_value (arg)) |
830bc550 RG |
1826 | && useless_type_conversion_p |
1827 | (TYPE_MAIN_VARIANT (TREE_VALUE (argt)), | |
84d77ca6 | 1828 | TYPE_MAIN_VARIANT (TREE_TYPE (val)))) |
830bc550 | 1829 | { |
84d77ca6 | 1830 | gimple_call_set_arg (stmt, i, unshare_expr (val)); |
830bc550 RG |
1831 | changed = true; |
1832 | } | |
1833 | } | |
74e80a24 | 1834 | |
830bc550 RG |
1835 | return changed; |
1836 | } | |
f61e18ec | 1837 | |
5c95f07b RG |
1838 | case GIMPLE_ASSIGN: |
1839 | { | |
1840 | tree lhs = gimple_assign_lhs (stmt); | |
84d77ca6 | 1841 | tree val; |
5c95f07b RG |
1842 | |
1843 | /* If we have a load that turned out to be constant replace it | |
1844 | as we cannot propagate into all uses in all cases. */ | |
1845 | if (gimple_assign_single_p (stmt) | |
1846 | && TREE_CODE (lhs) == SSA_NAME | |
84d77ca6 | 1847 | && (val = get_constant_value (lhs))) |
5c95f07b | 1848 | { |
84d77ca6 | 1849 | tree rhs = unshare_expr (val); |
5c95f07b | 1850 | if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs))) |
70f34814 | 1851 | rhs = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), rhs); |
5c95f07b RG |
1852 | gimple_assign_set_rhs_from_tree (gsi, rhs); |
1853 | return true; | |
1854 | } | |
1855 | ||
1856 | return false; | |
1857 | } | |
1858 | ||
830bc550 RG |
1859 | default: |
1860 | return false; | |
1861 | } | |
f61e18ec RG |
1862 | } |
1863 | ||
750628d8 | 1864 | /* Visit the assignment statement STMT. Set the value of its LHS to the |
0bca51f0 DN |
1865 | value computed by the RHS and store LHS in *OUTPUT_P. If STMT |
1866 | creates virtual definitions, set the value of each new name to that | |
726a989a RB |
1867 | of the RHS (if we can derive a constant out of the RHS). |
1868 | Value-returning call statements also perform an assignment, and | |
1869 | are handled here. */ | |
6de9cd9a | 1870 | |
750628d8 | 1871 | static enum ssa_prop_result |
726a989a | 1872 | visit_assignment (gimple stmt, tree *output_p) |
6de9cd9a | 1873 | { |
0bca51f0 | 1874 | prop_value_t val; |
0bca51f0 | 1875 | enum ssa_prop_result retval; |
6de9cd9a | 1876 | |
726a989a | 1877 | tree lhs = gimple_get_lhs (stmt); |
6de9cd9a | 1878 | |
726a989a RB |
1879 | gcc_assert (gimple_code (stmt) != GIMPLE_CALL |
1880 | || gimple_call_lhs (stmt) != NULL_TREE); | |
1881 | ||
84d77ca6 RG |
1882 | if (gimple_assign_single_p (stmt) |
1883 | && gimple_assign_rhs_code (stmt) == SSA_NAME) | |
1884 | /* For a simple copy operation, we copy the lattice values. */ | |
1885 | val = *get_value (gimple_assign_rhs1 (stmt)); | |
750628d8 | 1886 | else |
726a989a RB |
1887 | /* Evaluate the statement, which could be |
1888 | either a GIMPLE_ASSIGN or a GIMPLE_CALL. */ | |
87e1e42b | 1889 | val = evaluate_stmt (stmt); |
6de9cd9a | 1890 | |
0bca51f0 | 1891 | retval = SSA_PROP_NOT_INTERESTING; |
6de9cd9a | 1892 | |
750628d8 | 1893 | /* Set the lattice value of the statement's output. */ |
0bca51f0 | 1894 | if (TREE_CODE (lhs) == SSA_NAME) |
6de9cd9a | 1895 | { |
0bca51f0 DN |
1896 | /* If STMT is an assignment to an SSA_NAME, we only have one |
1897 | value to set. */ | |
1898 | if (set_lattice_value (lhs, val)) | |
1899 | { | |
1900 | *output_p = lhs; | |
1901 | if (val.lattice_val == VARYING) | |
1902 | retval = SSA_PROP_VARYING; | |
1903 | else | |
1904 | retval = SSA_PROP_INTERESTING; | |
1905 | } | |
6de9cd9a | 1906 | } |
0bca51f0 DN |
1907 | |
1908 | return retval; | |
6de9cd9a DN |
1909 | } |
1910 | ||
6de9cd9a | 1911 | |
750628d8 DN |
1912 | /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING |
1913 | if it can determine which edge will be taken. Otherwise, return | |
1914 | SSA_PROP_VARYING. */ | |
1915 | ||
1916 | static enum ssa_prop_result | |
726a989a | 1917 | visit_cond_stmt (gimple stmt, edge *taken_edge_p) |
6de9cd9a | 1918 | { |
0bca51f0 | 1919 | prop_value_t val; |
750628d8 DN |
1920 | basic_block block; |
1921 | ||
726a989a | 1922 | block = gimple_bb (stmt); |
750628d8 | 1923 | val = evaluate_stmt (stmt); |
0b4b14ac RG |
1924 | if (val.lattice_val != CONSTANT |
1925 | || !double_int_zero_p (val.mask)) | |
1926 | return SSA_PROP_VARYING; | |
750628d8 DN |
1927 | |
1928 | /* Find which edge out of the conditional block will be taken and add it | |
1929 | to the worklist. If no single edge can be determined statically, | |
1930 | return SSA_PROP_VARYING to feed all the outgoing edges to the | |
1931 | propagation engine. */ | |
0b4b14ac | 1932 | *taken_edge_p = find_taken_edge (block, val.value); |
750628d8 DN |
1933 | if (*taken_edge_p) |
1934 | return SSA_PROP_INTERESTING; | |
1935 | else | |
1936 | return SSA_PROP_VARYING; | |
6de9cd9a DN |
1937 | } |
1938 | ||
6de9cd9a | 1939 | |
750628d8 DN |
1940 | /* Evaluate statement STMT. If the statement produces an output value and |
1941 | its evaluation changes the lattice value of its output, return | |
1942 | SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the | |
1943 | output value. | |
b8698a0f | 1944 | |
750628d8 DN |
1945 | If STMT is a conditional branch and we can determine its truth |
1946 | value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying | |
1947 | value, return SSA_PROP_VARYING. */ | |
6de9cd9a | 1948 | |
750628d8 | 1949 | static enum ssa_prop_result |
726a989a | 1950 | ccp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p) |
750628d8 | 1951 | { |
750628d8 DN |
1952 | tree def; |
1953 | ssa_op_iter iter; | |
6de9cd9a | 1954 | |
750628d8 | 1955 | if (dump_file && (dump_flags & TDF_DETAILS)) |
6de9cd9a | 1956 | { |
0bca51f0 | 1957 | fprintf (dump_file, "\nVisiting statement:\n"); |
726a989a | 1958 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
6de9cd9a | 1959 | } |
6de9cd9a | 1960 | |
726a989a | 1961 | switch (gimple_code (stmt)) |
6de9cd9a | 1962 | { |
726a989a RB |
1963 | case GIMPLE_ASSIGN: |
1964 | /* If the statement is an assignment that produces a single | |
1965 | output value, evaluate its RHS to see if the lattice value of | |
1966 | its output has changed. */ | |
1967 | return visit_assignment (stmt, output_p); | |
1968 | ||
1969 | case GIMPLE_CALL: | |
1970 | /* A value-returning call also performs an assignment. */ | |
1971 | if (gimple_call_lhs (stmt) != NULL_TREE) | |
1972 | return visit_assignment (stmt, output_p); | |
1973 | break; | |
1974 | ||
1975 | case GIMPLE_COND: | |
1976 | case GIMPLE_SWITCH: | |
1977 | /* If STMT is a conditional branch, see if we can determine | |
1978 | which branch will be taken. */ | |
1979 | /* FIXME. It appears that we should be able to optimize | |
1980 | computed GOTOs here as well. */ | |
1981 | return visit_cond_stmt (stmt, taken_edge_p); | |
1982 | ||
1983 | default: | |
1984 | break; | |
6de9cd9a | 1985 | } |
6de9cd9a | 1986 | |
750628d8 DN |
1987 | /* Any other kind of statement is not interesting for constant |
1988 | propagation and, therefore, not worth simulating. */ | |
750628d8 DN |
1989 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1990 | fprintf (dump_file, "No interesting values produced. Marked VARYING.\n"); | |
6de9cd9a | 1991 | |
750628d8 DN |
1992 | /* Definitions made by statements other than assignments to |
1993 | SSA_NAMEs represent unknown modifications to their outputs. | |
1994 | Mark them VARYING. */ | |
0bca51f0 DN |
1995 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) |
1996 | { | |
0b4b14ac | 1997 | prop_value_t v = { VARYING, NULL_TREE, { -1, (HOST_WIDE_INT) -1 } }; |
0bca51f0 DN |
1998 | set_lattice_value (def, v); |
1999 | } | |
6de9cd9a | 2000 | |
750628d8 DN |
2001 | return SSA_PROP_VARYING; |
2002 | } | |
6de9cd9a | 2003 | |
6de9cd9a | 2004 | |
0bca51f0 | 2005 | /* Main entry point for SSA Conditional Constant Propagation. */ |
750628d8 | 2006 | |
3253eafb | 2007 | static unsigned int |
dce2b2f6 | 2008 | do_ssa_ccp (void) |
750628d8 DN |
2009 | { |
2010 | ccp_initialize (); | |
2011 | ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node); | |
3253eafb | 2012 | if (ccp_finalize ()) |
706ca88e | 2013 | return (TODO_cleanup_cfg | TODO_update_ssa | TODO_remove_unused_locals); |
3253eafb JH |
2014 | else |
2015 | return 0; | |
6de9cd9a DN |
2016 | } |
2017 | ||
173b818d BB |
2018 | |
2019 | static bool | |
750628d8 | 2020 | gate_ccp (void) |
173b818d | 2021 | { |
750628d8 | 2022 | return flag_tree_ccp != 0; |
173b818d BB |
2023 | } |
2024 | ||
6de9cd9a | 2025 | |
b8698a0f | 2026 | struct gimple_opt_pass pass_ccp = |
750628d8 | 2027 | { |
8ddbbcae JH |
2028 | { |
2029 | GIMPLE_PASS, | |
750628d8 DN |
2030 | "ccp", /* name */ |
2031 | gate_ccp, /* gate */ | |
0bca51f0 | 2032 | do_ssa_ccp, /* execute */ |
750628d8 DN |
2033 | NULL, /* sub */ |
2034 | NULL, /* next */ | |
2035 | 0, /* static_pass_number */ | |
2036 | TV_TREE_CCP, /* tv_id */ | |
7faade0f | 2037 | PROP_cfg | PROP_ssa, /* properties_required */ |
750628d8 | 2038 | 0, /* properties_provided */ |
ae07b463 | 2039 | 0, /* properties_destroyed */ |
750628d8 | 2040 | 0, /* todo_flags_start */ |
22c5fa5f | 2041 | TODO_verify_ssa |
8ddbbcae JH |
2042 | | TODO_verify_stmts | TODO_ggc_collect/* todo_flags_finish */ |
2043 | } | |
750628d8 | 2044 | }; |
6de9cd9a | 2045 | |
6de9cd9a | 2046 | |
726a989a | 2047 | |
cb8e078d JJ |
2048 | /* Try to optimize out __builtin_stack_restore. Optimize it out |
2049 | if there is another __builtin_stack_restore in the same basic | |
2050 | block and no calls or ASM_EXPRs are in between, or if this block's | |
2051 | only outgoing edge is to EXIT_BLOCK and there are no calls or | |
2052 | ASM_EXPRs after this __builtin_stack_restore. */ | |
2053 | ||
2054 | static tree | |
726a989a | 2055 | optimize_stack_restore (gimple_stmt_iterator i) |
cb8e078d | 2056 | { |
ff9d1adc RH |
2057 | tree callee; |
2058 | gimple stmt; | |
726a989a RB |
2059 | |
2060 | basic_block bb = gsi_bb (i); | |
2061 | gimple call = gsi_stmt (i); | |
cb8e078d | 2062 | |
726a989a RB |
2063 | if (gimple_code (call) != GIMPLE_CALL |
2064 | || gimple_call_num_args (call) != 1 | |
2065 | || TREE_CODE (gimple_call_arg (call, 0)) != SSA_NAME | |
2066 | || !POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call, 0)))) | |
cb8e078d JJ |
2067 | return NULL_TREE; |
2068 | ||
726a989a | 2069 | for (gsi_next (&i); !gsi_end_p (i); gsi_next (&i)) |
cb8e078d | 2070 | { |
726a989a RB |
2071 | stmt = gsi_stmt (i); |
2072 | if (gimple_code (stmt) == GIMPLE_ASM) | |
cb8e078d | 2073 | return NULL_TREE; |
726a989a | 2074 | if (gimple_code (stmt) != GIMPLE_CALL) |
cb8e078d JJ |
2075 | continue; |
2076 | ||
726a989a | 2077 | callee = gimple_call_fndecl (stmt); |
12f9ddbc RG |
2078 | if (!callee |
2079 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL | |
2080 | /* All regular builtins are ok, just obviously not alloca. */ | |
2081 | || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA) | |
cb8e078d JJ |
2082 | return NULL_TREE; |
2083 | ||
2084 | if (DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_RESTORE) | |
ff9d1adc | 2085 | goto second_stack_restore; |
cb8e078d JJ |
2086 | } |
2087 | ||
ff9d1adc | 2088 | if (!gsi_end_p (i)) |
cb8e078d JJ |
2089 | return NULL_TREE; |
2090 | ||
ff9d1adc RH |
2091 | /* Allow one successor of the exit block, or zero successors. */ |
2092 | switch (EDGE_COUNT (bb->succs)) | |
2093 | { | |
2094 | case 0: | |
2095 | break; | |
2096 | case 1: | |
2097 | if (single_succ_edge (bb)->dest != EXIT_BLOCK_PTR) | |
2098 | return NULL_TREE; | |
2099 | break; | |
2100 | default: | |
2101 | return NULL_TREE; | |
2102 | } | |
2103 | second_stack_restore: | |
cb8e078d | 2104 | |
ff9d1adc RH |
2105 | /* If there's exactly one use, then zap the call to __builtin_stack_save. |
2106 | If there are multiple uses, then the last one should remove the call. | |
2107 | In any case, whether the call to __builtin_stack_save can be removed | |
2108 | or not is irrelevant to removing the call to __builtin_stack_restore. */ | |
2109 | if (has_single_use (gimple_call_arg (call, 0))) | |
2110 | { | |
2111 | gimple stack_save = SSA_NAME_DEF_STMT (gimple_call_arg (call, 0)); | |
2112 | if (is_gimple_call (stack_save)) | |
2113 | { | |
2114 | callee = gimple_call_fndecl (stack_save); | |
2115 | if (callee | |
2116 | && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL | |
2117 | && DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_SAVE) | |
2118 | { | |
2119 | gimple_stmt_iterator stack_save_gsi; | |
2120 | tree rhs; | |
cb8e078d | 2121 | |
ff9d1adc RH |
2122 | stack_save_gsi = gsi_for_stmt (stack_save); |
2123 | rhs = build_int_cst (TREE_TYPE (gimple_call_arg (call, 0)), 0); | |
2124 | update_call_from_tree (&stack_save_gsi, rhs); | |
2125 | } | |
2126 | } | |
2127 | } | |
cb8e078d | 2128 | |
726a989a | 2129 | /* No effect, so the statement will be deleted. */ |
cb8e078d JJ |
2130 | return integer_zero_node; |
2131 | } | |
726a989a | 2132 | |
d7bd8aeb JJ |
2133 | /* If va_list type is a simple pointer and nothing special is needed, |
2134 | optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0), | |
2135 | __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple | |
2136 | pointer assignment. */ | |
2137 | ||
2138 | static tree | |
726a989a | 2139 | optimize_stdarg_builtin (gimple call) |
d7bd8aeb | 2140 | { |
35cbb299 | 2141 | tree callee, lhs, rhs, cfun_va_list; |
d7bd8aeb | 2142 | bool va_list_simple_ptr; |
db3927fb | 2143 | location_t loc = gimple_location (call); |
d7bd8aeb | 2144 | |
726a989a | 2145 | if (gimple_code (call) != GIMPLE_CALL) |
d7bd8aeb JJ |
2146 | return NULL_TREE; |
2147 | ||
726a989a | 2148 | callee = gimple_call_fndecl (call); |
35cbb299 KT |
2149 | |
2150 | cfun_va_list = targetm.fn_abi_va_list (callee); | |
2151 | va_list_simple_ptr = POINTER_TYPE_P (cfun_va_list) | |
2152 | && (TREE_TYPE (cfun_va_list) == void_type_node | |
2153 | || TREE_TYPE (cfun_va_list) == char_type_node); | |
2154 | ||
d7bd8aeb JJ |
2155 | switch (DECL_FUNCTION_CODE (callee)) |
2156 | { | |
2157 | case BUILT_IN_VA_START: | |
2158 | if (!va_list_simple_ptr | |
2159 | || targetm.expand_builtin_va_start != NULL | |
726a989a | 2160 | || built_in_decls[BUILT_IN_NEXT_ARG] == NULL) |
d7bd8aeb JJ |
2161 | return NULL_TREE; |
2162 | ||
726a989a | 2163 | if (gimple_call_num_args (call) != 2) |
d7bd8aeb JJ |
2164 | return NULL_TREE; |
2165 | ||
726a989a | 2166 | lhs = gimple_call_arg (call, 0); |
d7bd8aeb JJ |
2167 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) |
2168 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
35cbb299 | 2169 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
d7bd8aeb | 2170 | return NULL_TREE; |
b8698a0f | 2171 | |
db3927fb AH |
2172 | lhs = build_fold_indirect_ref_loc (loc, lhs); |
2173 | rhs = build_call_expr_loc (loc, built_in_decls[BUILT_IN_NEXT_ARG], | |
726a989a | 2174 | 1, integer_zero_node); |
db3927fb | 2175 | rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); |
d7bd8aeb JJ |
2176 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); |
2177 | ||
2178 | case BUILT_IN_VA_COPY: | |
2179 | if (!va_list_simple_ptr) | |
2180 | return NULL_TREE; | |
2181 | ||
726a989a | 2182 | if (gimple_call_num_args (call) != 2) |
d7bd8aeb JJ |
2183 | return NULL_TREE; |
2184 | ||
726a989a | 2185 | lhs = gimple_call_arg (call, 0); |
d7bd8aeb JJ |
2186 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) |
2187 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
35cbb299 | 2188 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
d7bd8aeb JJ |
2189 | return NULL_TREE; |
2190 | ||
db3927fb | 2191 | lhs = build_fold_indirect_ref_loc (loc, lhs); |
726a989a | 2192 | rhs = gimple_call_arg (call, 1); |
d7bd8aeb | 2193 | if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs)) |
35cbb299 | 2194 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
d7bd8aeb JJ |
2195 | return NULL_TREE; |
2196 | ||
db3927fb | 2197 | rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); |
d7bd8aeb JJ |
2198 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); |
2199 | ||
2200 | case BUILT_IN_VA_END: | |
726a989a | 2201 | /* No effect, so the statement will be deleted. */ |
d7bd8aeb JJ |
2202 | return integer_zero_node; |
2203 | ||
2204 | default: | |
2205 | gcc_unreachable (); | |
2206 | } | |
2207 | } | |
726a989a | 2208 | |
6de9cd9a DN |
2209 | /* A simple pass that attempts to fold all builtin functions. This pass |
2210 | is run after we've propagated as many constants as we can. */ | |
2211 | ||
c2924966 | 2212 | static unsigned int |
6de9cd9a DN |
2213 | execute_fold_all_builtins (void) |
2214 | { | |
a7d6ba24 | 2215 | bool cfg_changed = false; |
6de9cd9a | 2216 | basic_block bb; |
7b0e48fb | 2217 | unsigned int todoflags = 0; |
b8698a0f | 2218 | |
6de9cd9a DN |
2219 | FOR_EACH_BB (bb) |
2220 | { | |
726a989a RB |
2221 | gimple_stmt_iterator i; |
2222 | for (i = gsi_start_bb (bb); !gsi_end_p (i); ) | |
6de9cd9a | 2223 | { |
726a989a | 2224 | gimple stmt, old_stmt; |
6de9cd9a | 2225 | tree callee, result; |
10a0d495 | 2226 | enum built_in_function fcode; |
6de9cd9a | 2227 | |
726a989a RB |
2228 | stmt = gsi_stmt (i); |
2229 | ||
2230 | if (gimple_code (stmt) != GIMPLE_CALL) | |
10a0d495 | 2231 | { |
726a989a | 2232 | gsi_next (&i); |
10a0d495 JJ |
2233 | continue; |
2234 | } | |
726a989a | 2235 | callee = gimple_call_fndecl (stmt); |
6de9cd9a | 2236 | if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) |
10a0d495 | 2237 | { |
726a989a | 2238 | gsi_next (&i); |
10a0d495 JJ |
2239 | continue; |
2240 | } | |
2241 | fcode = DECL_FUNCTION_CODE (callee); | |
6de9cd9a | 2242 | |
cbdd87d4 | 2243 | result = gimple_fold_builtin (stmt); |
53a8f709 UB |
2244 | |
2245 | if (result) | |
726a989a | 2246 | gimple_remove_stmt_histograms (cfun, stmt); |
53a8f709 | 2247 | |
6de9cd9a DN |
2248 | if (!result) |
2249 | switch (DECL_FUNCTION_CODE (callee)) | |
2250 | { | |
2251 | case BUILT_IN_CONSTANT_P: | |
2252 | /* Resolve __builtin_constant_p. If it hasn't been | |
2253 | folded to integer_one_node by now, it's fairly | |
2254 | certain that the value simply isn't constant. */ | |
726a989a | 2255 | result = integer_zero_node; |
6de9cd9a DN |
2256 | break; |
2257 | ||
45d439ac JJ |
2258 | case BUILT_IN_ASSUME_ALIGNED: |
2259 | /* Remove __builtin_assume_aligned. */ | |
2260 | result = gimple_call_arg (stmt, 0); | |
2261 | break; | |
2262 | ||
cb8e078d | 2263 | case BUILT_IN_STACK_RESTORE: |
726a989a | 2264 | result = optimize_stack_restore (i); |
d7bd8aeb JJ |
2265 | if (result) |
2266 | break; | |
726a989a | 2267 | gsi_next (&i); |
d7bd8aeb JJ |
2268 | continue; |
2269 | ||
2270 | case BUILT_IN_VA_START: | |
2271 | case BUILT_IN_VA_END: | |
2272 | case BUILT_IN_VA_COPY: | |
2273 | /* These shouldn't be folded before pass_stdarg. */ | |
726a989a | 2274 | result = optimize_stdarg_builtin (stmt); |
cb8e078d JJ |
2275 | if (result) |
2276 | break; | |
2277 | /* FALLTHRU */ | |
2278 | ||
6de9cd9a | 2279 | default: |
726a989a | 2280 | gsi_next (&i); |
6de9cd9a DN |
2281 | continue; |
2282 | } | |
2283 | ||
2284 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2285 | { | |
2286 | fprintf (dump_file, "Simplified\n "); | |
726a989a | 2287 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
6de9cd9a DN |
2288 | } |
2289 | ||
726a989a | 2290 | old_stmt = stmt; |
726a989a | 2291 | if (!update_call_from_tree (&i, result)) |
4bad83f5 RG |
2292 | { |
2293 | gimplify_and_update_call_from_tree (&i, result); | |
2294 | todoflags |= TODO_update_address_taken; | |
2295 | } | |
cfaab3a9 | 2296 | |
726a989a | 2297 | stmt = gsi_stmt (i); |
cff4e50d | 2298 | update_stmt (stmt); |
cfaab3a9 | 2299 | |
726a989a RB |
2300 | if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt) |
2301 | && gimple_purge_dead_eh_edges (bb)) | |
a7d6ba24 | 2302 | cfg_changed = true; |
6de9cd9a DN |
2303 | |
2304 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2305 | { | |
2306 | fprintf (dump_file, "to\n "); | |
726a989a | 2307 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
6de9cd9a DN |
2308 | fprintf (dump_file, "\n"); |
2309 | } | |
10a0d495 JJ |
2310 | |
2311 | /* Retry the same statement if it changed into another | |
2312 | builtin, there might be new opportunities now. */ | |
726a989a | 2313 | if (gimple_code (stmt) != GIMPLE_CALL) |
10a0d495 | 2314 | { |
726a989a | 2315 | gsi_next (&i); |
10a0d495 JJ |
2316 | continue; |
2317 | } | |
726a989a | 2318 | callee = gimple_call_fndecl (stmt); |
10a0d495 | 2319 | if (!callee |
726a989a | 2320 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL |
10a0d495 | 2321 | || DECL_FUNCTION_CODE (callee) == fcode) |
726a989a | 2322 | gsi_next (&i); |
6de9cd9a DN |
2323 | } |
2324 | } | |
b8698a0f | 2325 | |
a7d6ba24 | 2326 | /* Delete unreachable blocks. */ |
7b0e48fb DB |
2327 | if (cfg_changed) |
2328 | todoflags |= TODO_cleanup_cfg; | |
b8698a0f | 2329 | |
7b0e48fb | 2330 | return todoflags; |
6de9cd9a DN |
2331 | } |
2332 | ||
750628d8 | 2333 | |
b8698a0f | 2334 | struct gimple_opt_pass pass_fold_builtins = |
6de9cd9a | 2335 | { |
8ddbbcae JH |
2336 | { |
2337 | GIMPLE_PASS, | |
6de9cd9a DN |
2338 | "fab", /* name */ |
2339 | NULL, /* gate */ | |
2340 | execute_fold_all_builtins, /* execute */ | |
2341 | NULL, /* sub */ | |
2342 | NULL, /* next */ | |
2343 | 0, /* static_pass_number */ | |
7072a650 | 2344 | TV_NONE, /* tv_id */ |
7faade0f | 2345 | PROP_cfg | PROP_ssa, /* properties_required */ |
6de9cd9a DN |
2346 | 0, /* properties_provided */ |
2347 | 0, /* properties_destroyed */ | |
2348 | 0, /* todo_flags_start */ | |
22c5fa5f | 2349 | TODO_verify_ssa |
8ddbbcae JH |
2350 | | TODO_update_ssa /* todo_flags_finish */ |
2351 | } | |
6de9cd9a | 2352 | }; |