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34f97b94 | 1 | /* Predicate aware uninitialized variable warning. |
8d9254fc | 2 | Copyright (C) 2001-2020 Free Software Foundation, Inc. |
34f97b94 XDL |
3 | Contributed by Xinliang David Li <davidxl@google.com> |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 3, or (at your option) | |
10 | any later version. | |
11 | ||
12 | GCC is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with GCC; see the file COPYING3. If not see | |
19 | <http://www.gnu.org/licenses/>. */ | |
20 | ||
21 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
c7131fb2 | 24 | #include "backend.h" |
34f97b94 | 25 | #include "tree.h" |
c7131fb2 | 26 | #include "gimple.h" |
957060b5 | 27 | #include "tree-pass.h" |
c7131fb2 | 28 | #include "ssa.h" |
957060b5 AM |
29 | #include "gimple-pretty-print.h" |
30 | #include "diagnostic-core.h" | |
40e23961 | 31 | #include "fold-const.h" |
5be5c238 | 32 | #include "gimple-iterator.h" |
442b4905 | 33 | #include "tree-ssa.h" |
666e8e06 | 34 | #include "tree-cfg.h" |
11ef0b22 | 35 | #include "cfghooks.h" |
34f97b94 XDL |
36 | |
37 | /* This implements the pass that does predicate aware warning on uses of | |
ac0e4fde ML |
38 | possibly uninitialized variables. The pass first collects the set of |
39 | possibly uninitialized SSA names. For each such name, it walks through | |
40 | all its immediate uses. For each immediate use, it rebuilds the condition | |
41 | expression (the predicate) that guards the use. The predicate is then | |
34f97b94 XDL |
42 | examined to see if the variable is always defined under that same condition. |
43 | This is done either by pruning the unrealizable paths that lead to the | |
44 | default definitions or by checking if the predicate set that guards the | |
45 | defining paths is a superset of the use predicate. */ | |
46 | ||
358a95e4 AH |
47 | /* Max PHI args we can handle in pass. */ |
48 | const unsigned max_phi_args = 32; | |
49 | ||
34f97b94 XDL |
50 | /* Pointer set of potentially undefined ssa names, i.e., |
51 | ssa names that are defined by phi with operands that | |
52 | are not defined or potentially undefined. */ | |
6e2830c3 | 53 | static hash_set<tree> *possibly_undefined_names = 0; |
34f97b94 XDL |
54 | |
55 | /* Bit mask handling macros. */ | |
56 | #define MASK_SET_BIT(mask, pos) mask |= (1 << pos) | |
57 | #define MASK_TEST_BIT(mask, pos) (mask & (1 << pos)) | |
58 | #define MASK_EMPTY(mask) (mask == 0) | |
59 | ||
60 | /* Returns the first bit position (starting from LSB) | |
ac0e4fde | 61 | in mask that is non zero. Returns -1 if the mask is empty. */ |
34f97b94 XDL |
62 | static int |
63 | get_mask_first_set_bit (unsigned mask) | |
64 | { | |
65 | int pos = 0; | |
66 | if (mask == 0) | |
67 | return -1; | |
68 | ||
69 | while ((mask & (1 << pos)) == 0) | |
70 | pos++; | |
71 | ||
72 | return pos; | |
73 | } | |
74 | #define MASK_FIRST_SET_BIT(mask) get_mask_first_set_bit (mask) | |
75 | ||
34f97b94 | 76 | /* Return true if T, an SSA_NAME, has an undefined value. */ |
c152901f AM |
77 | static bool |
78 | has_undefined_value_p (tree t) | |
34f97b94 | 79 | { |
c152901f | 80 | return (ssa_undefined_value_p (t) |
5e48d8a0 ML |
81 | || (possibly_undefined_names |
82 | && possibly_undefined_names->contains (t))); | |
34f97b94 XDL |
83 | } |
84 | ||
c152901f | 85 | /* Like has_undefined_value_p, but don't return true if TREE_NO_WARNING |
ba7e83f8 JJ |
86 | is set on SSA_NAME_VAR. */ |
87 | ||
88 | static inline bool | |
ac0e4fde ML |
89 | uninit_undefined_value_p (tree t) |
90 | { | |
c152901f | 91 | if (!has_undefined_value_p (t)) |
ba7e83f8 JJ |
92 | return false; |
93 | if (SSA_NAME_VAR (t) && TREE_NO_WARNING (SSA_NAME_VAR (t))) | |
94 | return false; | |
95 | return true; | |
96 | } | |
97 | ||
c152901f AM |
98 | /* Emit warnings for uninitialized variables. This is done in two passes. |
99 | ||
100 | The first pass notices real uses of SSA names with undefined values. | |
101 | Such uses are unconditionally uninitialized, and we can be certain that | |
102 | such a use is a mistake. This pass is run before most optimizations, | |
103 | so that we catch as many as we can. | |
104 | ||
105 | The second pass follows PHI nodes to find uses that are potentially | |
106 | uninitialized. In this case we can't necessarily prove that the use | |
107 | is really uninitialized. This pass is run after most optimizations, | |
108 | so that we thread as many jumps and possible, and delete as much dead | |
109 | code as possible, in order to reduce false positives. We also look | |
110 | again for plain uninitialized variables, since optimization may have | |
111 | changed conditionally uninitialized to unconditionally uninitialized. */ | |
112 | ||
113 | /* Emit a warning for EXPR based on variable VAR at the point in the | |
114 | program T, an SSA_NAME, is used being uninitialized. The exact | |
e1ec47c4 | 115 | warning text is in MSGID and DATA is the gimple stmt with info about |
ac0e4fde | 116 | the location in source code. When DATA is a GIMPLE_PHI, PHIARG_IDX |
e1ec47c4 TP |
117 | gives which argument of the phi node to take the location from. WC |
118 | is the warning code. */ | |
c152901f AM |
119 | |
120 | static void | |
e1ec47c4 TP |
121 | warn_uninit (enum opt_code wc, tree t, tree expr, tree var, |
122 | const char *gmsgid, void *data, location_t phiarg_loc) | |
c152901f | 123 | { |
355fe088 | 124 | gimple *context = (gimple *) data; |
c152901f AM |
125 | location_t location, cfun_loc; |
126 | expanded_location xloc, floc; | |
127 | ||
e1ec47c4 TP |
128 | /* Ignore COMPLEX_EXPR as initializing only a part of a complex |
129 | turns in a COMPLEX_EXPR with the not initialized part being | |
130 | set to its previous (undefined) value. */ | |
131 | if (is_gimple_assign (context) | |
132 | && gimple_assign_rhs_code (context) == COMPLEX_EXPR) | |
133 | return; | |
c152901f AM |
134 | if (!has_undefined_value_p (t)) |
135 | return; | |
136 | ||
50aa64d5 JJ |
137 | /* Anonymous SSA_NAMEs shouldn't be uninitialized, but ssa_undefined_value_p |
138 | can return true if the def stmt of anonymous SSA_NAME is COMPLEX_EXPR | |
139 | created for conversion from scalar to complex. Use the underlying var of | |
140 | the COMPLEX_EXPRs real part in that case. See PR71581. */ | |
141 | if (expr == NULL_TREE | |
142 | && var == NULL_TREE | |
143 | && SSA_NAME_VAR (t) == NULL_TREE | |
144 | && is_gimple_assign (SSA_NAME_DEF_STMT (t)) | |
145 | && gimple_assign_rhs_code (SSA_NAME_DEF_STMT (t)) == COMPLEX_EXPR) | |
146 | { | |
147 | tree v = gimple_assign_rhs1 (SSA_NAME_DEF_STMT (t)); | |
148 | if (TREE_CODE (v) == SSA_NAME | |
149 | && has_undefined_value_p (v) | |
150 | && zerop (gimple_assign_rhs2 (SSA_NAME_DEF_STMT (t)))) | |
151 | { | |
152 | expr = SSA_NAME_VAR (v); | |
153 | var = expr; | |
154 | } | |
155 | } | |
156 | ||
157 | if (expr == NULL_TREE) | |
158 | return; | |
159 | ||
c152901f AM |
160 | /* TREE_NO_WARNING either means we already warned, or the front end |
161 | wishes to suppress the warning. */ | |
162 | if ((context | |
163 | && (gimple_no_warning_p (context) | |
164 | || (gimple_assign_single_p (context) | |
165 | && TREE_NO_WARNING (gimple_assign_rhs1 (context))))) | |
166 | || TREE_NO_WARNING (expr)) | |
167 | return; | |
168 | ||
e1ec47c4 TP |
169 | if (context != NULL && gimple_has_location (context)) |
170 | location = gimple_location (context); | |
171 | else if (phiarg_loc != UNKNOWN_LOCATION) | |
172 | location = phiarg_loc; | |
173 | else | |
174 | location = DECL_SOURCE_LOCATION (var); | |
c152901f | 175 | location = linemap_resolve_location (line_table, location, |
ac0e4fde | 176 | LRK_SPELLING_LOCATION, NULL); |
c152901f AM |
177 | cfun_loc = DECL_SOURCE_LOCATION (cfun->decl); |
178 | xloc = expand_location (location); | |
179 | floc = expand_location (cfun_loc); | |
097f82ec | 180 | auto_diagnostic_group d; |
c152901f AM |
181 | if (warning_at (location, wc, gmsgid, expr)) |
182 | { | |
183 | TREE_NO_WARNING (expr) = 1; | |
184 | ||
185 | if (location == DECL_SOURCE_LOCATION (var)) | |
186 | return; | |
187 | if (xloc.file != floc.file | |
ac0e4fde ML |
188 | || linemap_location_before_p (line_table, location, cfun_loc) |
189 | || linemap_location_before_p (line_table, cfun->function_end_locus, | |
c152901f AM |
190 | location)) |
191 | inform (DECL_SOURCE_LOCATION (var), "%qD was declared here", var); | |
192 | } | |
193 | } | |
194 | ||
e80facb4 RB |
195 | struct check_defs_data |
196 | { | |
197 | /* If we found any may-defs besides must-def clobbers. */ | |
198 | bool found_may_defs; | |
199 | }; | |
200 | ||
201 | /* Callback for walk_aliased_vdefs. */ | |
202 | ||
203 | static bool | |
204 | check_defs (ao_ref *ref, tree vdef, void *data_) | |
205 | { | |
206 | check_defs_data *data = (check_defs_data *)data_; | |
207 | gimple *def_stmt = SSA_NAME_DEF_STMT (vdef); | |
208 | /* If this is a clobber then if it is not a kill walk past it. */ | |
209 | if (gimple_clobber_p (def_stmt)) | |
210 | { | |
211 | if (stmt_kills_ref_p (def_stmt, ref)) | |
212 | return true; | |
213 | return false; | |
214 | } | |
215 | /* Found a may-def on this path. */ | |
216 | data->found_may_defs = true; | |
217 | return true; | |
218 | } | |
219 | ||
c152901f AM |
220 | static unsigned int |
221 | warn_uninitialized_vars (bool warn_possibly_uninitialized) | |
222 | { | |
223 | gimple_stmt_iterator gsi; | |
224 | basic_block bb; | |
e80facb4 RB |
225 | unsigned int vdef_cnt = 0; |
226 | unsigned int oracle_cnt = 0; | |
227 | unsigned limit = 0; | |
c152901f | 228 | |
11cd3bed | 229 | FOR_EACH_BB_FN (bb, cfun) |
c152901f | 230 | { |
ac0e4fde ML |
231 | basic_block succ = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
232 | bool always_executed = dominated_by_p (CDI_POST_DOMINATORS, succ, bb); | |
c152901f AM |
233 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
234 | { | |
355fe088 | 235 | gimple *stmt = gsi_stmt (gsi); |
c152901f AM |
236 | use_operand_p use_p; |
237 | ssa_op_iter op_iter; | |
238 | tree use; | |
239 | ||
240 | if (is_gimple_debug (stmt)) | |
241 | continue; | |
242 | ||
243 | /* We only do data flow with SSA_NAMEs, so that's all we | |
244 | can warn about. */ | |
245 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, op_iter, SSA_OP_USE) | |
246 | { | |
d07f8c59 RB |
247 | /* BIT_INSERT_EXPR first operand should not be considered |
248 | a use for the purpose of uninit warnings. */ | |
249 | if (gassign *ass = dyn_cast <gassign *> (stmt)) | |
250 | { | |
251 | if (gimple_assign_rhs_code (ass) == BIT_INSERT_EXPR | |
252 | && use_p->use == gimple_assign_rhs1_ptr (ass)) | |
253 | continue; | |
254 | } | |
c152901f AM |
255 | use = USE_FROM_PTR (use_p); |
256 | if (always_executed) | |
ac0e4fde ML |
257 | warn_uninit (OPT_Wuninitialized, use, SSA_NAME_VAR (use), |
258 | SSA_NAME_VAR (use), | |
259 | "%qD is used uninitialized in this function", stmt, | |
260 | UNKNOWN_LOCATION); | |
c152901f | 261 | else if (warn_possibly_uninitialized) |
ac0e4fde ML |
262 | warn_uninit (OPT_Wmaybe_uninitialized, use, SSA_NAME_VAR (use), |
263 | SSA_NAME_VAR (use), | |
c152901f | 264 | "%qD may be used uninitialized in this function", |
e1ec47c4 | 265 | stmt, UNKNOWN_LOCATION); |
c152901f AM |
266 | } |
267 | ||
e80facb4 RB |
268 | /* For limiting the alias walk below we count all |
269 | vdefs in the function. */ | |
270 | if (gimple_vdef (stmt)) | |
271 | vdef_cnt++; | |
272 | ||
273 | if (gimple_assign_load_p (stmt) | |
274 | && gimple_has_location (stmt)) | |
c152901f AM |
275 | { |
276 | tree rhs = gimple_assign_rhs1 (stmt); | |
6d20bf18 AP |
277 | tree lhs = gimple_assign_lhs (stmt); |
278 | bool has_bit_insert = false; | |
279 | use_operand_p luse_p; | |
280 | imm_use_iterator liter; | |
281 | ||
e80facb4 RB |
282 | if (TREE_NO_WARNING (rhs)) |
283 | continue; | |
284 | ||
285 | ao_ref ref; | |
286 | ao_ref_init (&ref, rhs); | |
c152901f | 287 | |
d21a8e3b RB |
288 | /* Do not warn if the base was marked so or this is a |
289 | hard register var. */ | |
e80facb4 | 290 | tree base = ao_ref_base (&ref); |
d21a8e3b RB |
291 | if ((VAR_P (base) |
292 | && DECL_HARD_REGISTER (base)) | |
e80facb4 RB |
293 | || TREE_NO_WARNING (base)) |
294 | continue; | |
295 | ||
edfcd7e3 RB |
296 | /* Do not warn if the access is fully outside of the |
297 | variable. */ | |
b9c25734 | 298 | poly_int64 decl_size; |
d21a8e3b | 299 | if (DECL_P (base) |
b9c25734 RS |
300 | && known_size_p (ref.size) |
301 | && ((known_eq (ref.max_size, ref.size) | |
302 | && known_le (ref.offset + ref.size, 0)) | |
303 | || (known_ge (ref.offset, 0) | |
d21a8e3b | 304 | && DECL_SIZE (base) |
b9c25734 RS |
305 | && poly_int_tree_p (DECL_SIZE (base), &decl_size) |
306 | && known_le (decl_size, ref.offset)))) | |
edfcd7e3 RB |
307 | continue; |
308 | ||
6d20bf18 AP |
309 | /* Do not warn if the access is then used for a BIT_INSERT_EXPR. */ |
310 | if (TREE_CODE (lhs) == SSA_NAME) | |
311 | FOR_EACH_IMM_USE_FAST (luse_p, liter, lhs) | |
312 | { | |
313 | gimple *use_stmt = USE_STMT (luse_p); | |
314 | /* BIT_INSERT_EXPR first operand should not be considered | |
315 | a use for the purpose of uninit warnings. */ | |
316 | if (gassign *ass = dyn_cast <gassign *> (use_stmt)) | |
317 | { | |
318 | if (gimple_assign_rhs_code (ass) == BIT_INSERT_EXPR | |
319 | && luse_p->use == gimple_assign_rhs1_ptr (ass)) | |
320 | { | |
321 | has_bit_insert = true; | |
322 | break; | |
323 | } | |
324 | } | |
325 | } | |
326 | if (has_bit_insert) | |
327 | continue; | |
328 | ||
e80facb4 RB |
329 | /* Limit the walking to a constant number of stmts after |
330 | we overcommit quadratic behavior for small functions | |
331 | and O(n) behavior. */ | |
332 | if (oracle_cnt > 128 * 128 | |
333 | && oracle_cnt > vdef_cnt * 2) | |
334 | limit = 32; | |
335 | check_defs_data data; | |
d21a8e3b | 336 | bool fentry_reached = false; |
e80facb4 RB |
337 | data.found_may_defs = false; |
338 | use = gimple_vuse (stmt); | |
339 | int res = walk_aliased_vdefs (&ref, use, | |
340 | check_defs, &data, NULL, | |
d21a8e3b | 341 | &fentry_reached, limit); |
e80facb4 RB |
342 | if (res == -1) |
343 | { | |
344 | oracle_cnt += limit; | |
345 | continue; | |
346 | } | |
347 | oracle_cnt += res; | |
348 | if (data.found_may_defs) | |
c152901f | 349 | continue; |
d21a8e3b RB |
350 | /* Do not warn if it can be initialized outside this function. |
351 | If we did not reach function entry then we found killing | |
352 | clobbers on all paths to entry. */ | |
353 | if (fentry_reached | |
354 | /* ??? We'd like to use ref_may_alias_global_p but that | |
355 | excludes global readonly memory and thus we get bougs | |
356 | warnings from p = cond ? "a" : "b" for example. */ | |
357 | && (!VAR_P (base) | |
358 | || is_global_var (base))) | |
359 | continue; | |
c152901f | 360 | |
e80facb4 RB |
361 | /* We didn't find any may-defs so on all paths either |
362 | reached function entry or a killing clobber. */ | |
363 | location_t location | |
364 | = linemap_resolve_location (line_table, gimple_location (stmt), | |
365 | LRK_SPELLING_LOCATION, NULL); | |
c152901f | 366 | if (always_executed) |
e80facb4 RB |
367 | { |
368 | if (warning_at (location, OPT_Wuninitialized, | |
369 | "%qE is used uninitialized in this function", | |
370 | rhs)) | |
371 | /* ??? This is only effective for decls as in | |
372 | gcc.dg/uninit-B-O0.c. Avoid doing this for | |
373 | maybe-uninit uses as it may hide important | |
374 | locations. */ | |
375 | TREE_NO_WARNING (rhs) = 1; | |
376 | } | |
c152901f | 377 | else if (warn_possibly_uninitialized) |
e80facb4 RB |
378 | warning_at (location, OPT_Wmaybe_uninitialized, |
379 | "%qE may be used uninitialized in this function", | |
380 | rhs); | |
c152901f AM |
381 | } |
382 | } | |
383 | } | |
384 | ||
385 | return 0; | |
386 | } | |
387 | ||
927734cf XDL |
388 | /* Checks if the operand OPND of PHI is defined by |
389 | another phi with one operand defined by this PHI, | |
ac0e4fde | 390 | but the rest operands are all defined. If yes, |
026c3cfd | 391 | returns true to skip this operand as being |
ac0e4fde | 392 | redundant. Can be enhanced to be more general. */ |
34f97b94 XDL |
393 | |
394 | static bool | |
355fe088 | 395 | can_skip_redundant_opnd (tree opnd, gimple *phi) |
34f97b94 | 396 | { |
355fe088 | 397 | gimple *op_def; |
34f97b94 XDL |
398 | tree phi_def; |
399 | int i, n; | |
400 | ||
401 | phi_def = gimple_phi_result (phi); | |
402 | op_def = SSA_NAME_DEF_STMT (opnd); | |
403 | if (gimple_code (op_def) != GIMPLE_PHI) | |
404 | return false; | |
405 | n = gimple_phi_num_args (op_def); | |
406 | for (i = 0; i < n; ++i) | |
407 | { | |
408 | tree op = gimple_phi_arg_def (op_def, i); | |
409 | if (TREE_CODE (op) != SSA_NAME) | |
5e48d8a0 | 410 | continue; |
ba7e83f8 | 411 | if (op != phi_def && uninit_undefined_value_p (op)) |
5e48d8a0 | 412 | return false; |
34f97b94 XDL |
413 | } |
414 | ||
415 | return true; | |
416 | } | |
417 | ||
418 | /* Returns a bit mask holding the positions of arguments in PHI | |
419 | that have empty (or possibly empty) definitions. */ | |
420 | ||
421 | static unsigned | |
538dd0b7 | 422 | compute_uninit_opnds_pos (gphi *phi) |
34f97b94 XDL |
423 | { |
424 | size_t i, n; | |
425 | unsigned uninit_opnds = 0; | |
426 | ||
427 | n = gimple_phi_num_args (phi); | |
98d30e4f | 428 | /* Bail out for phi with too many args. */ |
358a95e4 | 429 | if (n > max_phi_args) |
98d30e4f | 430 | return 0; |
34f97b94 XDL |
431 | |
432 | for (i = 0; i < n; ++i) | |
433 | { | |
434 | tree op = gimple_phi_arg_def (phi, i); | |
435 | if (TREE_CODE (op) == SSA_NAME | |
5e48d8a0 ML |
436 | && uninit_undefined_value_p (op) |
437 | && !can_skip_redundant_opnd (op, phi)) | |
e7d764f3 | 438 | { |
5e48d8a0 | 439 | if (cfun->has_nonlocal_label || cfun->calls_setjmp) |
e7d764f3 | 440 | { |
aea0101d RB |
441 | /* Ignore SSA_NAMEs that appear on abnormal edges |
442 | somewhere. */ | |
443 | if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op)) | |
444 | continue; | |
e7d764f3 JJ |
445 | } |
446 | MASK_SET_BIT (uninit_opnds, i); | |
447 | } | |
34f97b94 XDL |
448 | } |
449 | return uninit_opnds; | |
450 | } | |
451 | ||
452 | /* Find the immediate postdominator PDOM of the specified | |
453 | basic block BLOCK. */ | |
454 | ||
455 | static inline basic_block | |
456 | find_pdom (basic_block block) | |
457 | { | |
ac0e4fde ML |
458 | if (block == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
459 | return EXIT_BLOCK_PTR_FOR_FN (cfun); | |
460 | else | |
461 | { | |
462 | basic_block bb = get_immediate_dominator (CDI_POST_DOMINATORS, block); | |
463 | if (!bb) | |
464 | return EXIT_BLOCK_PTR_FOR_FN (cfun); | |
465 | return bb; | |
466 | } | |
34f97b94 XDL |
467 | } |
468 | ||
ac0e4fde | 469 | /* Find the immediate DOM of the specified basic block BLOCK. */ |
34f97b94 XDL |
470 | |
471 | static inline basic_block | |
472 | find_dom (basic_block block) | |
473 | { | |
ac0e4fde ML |
474 | if (block == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
475 | return ENTRY_BLOCK_PTR_FOR_FN (cfun); | |
476 | else | |
477 | { | |
478 | basic_block bb = get_immediate_dominator (CDI_DOMINATORS, block); | |
479 | if (!bb) | |
480 | return ENTRY_BLOCK_PTR_FOR_FN (cfun); | |
481 | return bb; | |
482 | } | |
34f97b94 XDL |
483 | } |
484 | ||
485 | /* Returns true if BB1 is postdominating BB2 and BB1 is | |
ac0e4fde | 486 | not a loop exit bb. The loop exit bb check is simple and does |
34f97b94 XDL |
487 | not cover all cases. */ |
488 | ||
489 | static bool | |
490 | is_non_loop_exit_postdominating (basic_block bb1, basic_block bb2) | |
491 | { | |
492 | if (!dominated_by_p (CDI_POST_DOMINATORS, bb2, bb1)) | |
493 | return false; | |
494 | ||
495 | if (single_pred_p (bb1) && !single_succ_p (bb2)) | |
496 | return false; | |
497 | ||
498 | return true; | |
499 | } | |
500 | ||
501 | /* Find the closest postdominator of a specified BB, which is control | |
502 | equivalent to BB. */ | |
503 | ||
ac0e4fde | 504 | static inline basic_block |
34f97b94 XDL |
505 | find_control_equiv_block (basic_block bb) |
506 | { | |
507 | basic_block pdom; | |
508 | ||
509 | pdom = find_pdom (bb); | |
510 | ||
511 | /* Skip the postdominating bb that is also loop exit. */ | |
512 | if (!is_non_loop_exit_postdominating (pdom, bb)) | |
513 | return NULL; | |
514 | ||
515 | if (dominated_by_p (CDI_DOMINATORS, pdom, bb)) | |
516 | return pdom; | |
517 | ||
518 | return NULL; | |
519 | } | |
520 | ||
521 | #define MAX_NUM_CHAINS 8 | |
522 | #define MAX_CHAIN_LEN 5 | |
4dc1d68c | 523 | #define MAX_POSTDOM_CHECK 8 |
666e8e06 | 524 | #define MAX_SWITCH_CASES 40 |
34f97b94 XDL |
525 | |
526 | /* Computes the control dependence chains (paths of edges) | |
527 | for DEP_BB up to the dominating basic block BB (the head node of a | |
92261ce0 JJ |
528 | chain should be dominated by it). CD_CHAINS is pointer to an |
529 | array holding the result chains. CUR_CD_CHAIN is the current | |
34f97b94 XDL |
530 | chain being computed. *NUM_CHAINS is total number of chains. The |
531 | function returns true if the information is successfully computed, | |
532 | return false if there is no control dependence or not computed. */ | |
533 | ||
534 | static bool | |
535 | compute_control_dep_chain (basic_block bb, basic_block dep_bb, | |
5e48d8a0 ML |
536 | vec<edge> *cd_chains, |
537 | size_t *num_chains, | |
92261ce0 JJ |
538 | vec<edge> *cur_cd_chain, |
539 | int *num_calls) | |
34f97b94 XDL |
540 | { |
541 | edge_iterator ei; | |
542 | edge e; | |
543 | size_t i; | |
544 | bool found_cd_chain = false; | |
545 | size_t cur_chain_len = 0; | |
546 | ||
028d4092 | 547 | if (*num_calls > param_uninit_control_dep_attempts) |
92261ce0 JJ |
548 | return false; |
549 | ++*num_calls; | |
550 | ||
927734cf | 551 | /* Could use a set instead. */ |
9771b263 | 552 | cur_chain_len = cur_cd_chain->length (); |
34f97b94 XDL |
553 | if (cur_chain_len > MAX_CHAIN_LEN) |
554 | return false; | |
555 | ||
556 | for (i = 0; i < cur_chain_len; i++) | |
557 | { | |
9771b263 | 558 | edge e = (*cur_cd_chain)[i]; |
ac0e4fde | 559 | /* Cycle detected. */ |
34f97b94 | 560 | if (e->src == bb) |
5e48d8a0 | 561 | return false; |
34f97b94 XDL |
562 | } |
563 | ||
564 | FOR_EACH_EDGE (e, ei, bb->succs) | |
565 | { | |
566 | basic_block cd_bb; | |
4dc1d68c | 567 | int post_dom_check = 0; |
34f97b94 | 568 | if (e->flags & (EDGE_FAKE | EDGE_ABNORMAL)) |
5e48d8a0 | 569 | continue; |
34f97b94 XDL |
570 | |
571 | cd_bb = e->dest; | |
9771b263 | 572 | cur_cd_chain->safe_push (e); |
34f97b94 | 573 | while (!is_non_loop_exit_postdominating (cd_bb, bb)) |
5e48d8a0 ML |
574 | { |
575 | if (cd_bb == dep_bb) | |
576 | { | |
577 | /* Found a direct control dependence. */ | |
578 | if (*num_chains < MAX_NUM_CHAINS) | |
579 | { | |
580 | cd_chains[*num_chains] = cur_cd_chain->copy (); | |
581 | (*num_chains)++; | |
582 | } | |
583 | found_cd_chain = true; | |
584 | /* Check path from next edge. */ | |
585 | break; | |
586 | } | |
587 | ||
588 | /* Now check if DEP_BB is indirectly control dependent on BB. */ | |
ac0e4fde ML |
589 | if (compute_control_dep_chain (cd_bb, dep_bb, cd_chains, num_chains, |
590 | cur_cd_chain, num_calls)) | |
5e48d8a0 ML |
591 | { |
592 | found_cd_chain = true; | |
593 | break; | |
594 | } | |
34f97b94 | 595 | |
5e48d8a0 ML |
596 | cd_bb = find_pdom (cd_bb); |
597 | post_dom_check++; | |
ac0e4fde ML |
598 | if (cd_bb == EXIT_BLOCK_PTR_FOR_FN (cfun) |
599 | || post_dom_check > MAX_POSTDOM_CHECK) | |
5e48d8a0 ML |
600 | break; |
601 | } | |
9771b263 DN |
602 | cur_cd_chain->pop (); |
603 | gcc_assert (cur_cd_chain->length () == cur_chain_len); | |
34f97b94 | 604 | } |
9771b263 | 605 | gcc_assert (cur_cd_chain->length () == cur_chain_len); |
34f97b94 XDL |
606 | |
607 | return found_cd_chain; | |
608 | } | |
609 | ||
ac0e4fde | 610 | /* The type to represent a simple predicate. */ |
927734cf | 611 | |
a79683d5 | 612 | struct pred_info |
34f97b94 | 613 | { |
927734cf XDL |
614 | tree pred_lhs; |
615 | tree pred_rhs; | |
616 | enum tree_code cond_code; | |
34f97b94 | 617 | bool invert; |
a79683d5 | 618 | }; |
927734cf XDL |
619 | |
620 | /* The type to represent a sequence of predicates grouped | |
621 | with .AND. operation. */ | |
34f97b94 | 622 | |
927734cf | 623 | typedef vec<pred_info, va_heap, vl_ptr> pred_chain; |
34f97b94 | 624 | |
927734cf XDL |
625 | /* The type to represent a sequence of pred_chains grouped |
626 | with .OR. operation. */ | |
627 | ||
628 | typedef vec<pred_chain, va_heap, vl_ptr> pred_chain_union; | |
34f97b94 XDL |
629 | |
630 | /* Converts the chains of control dependence edges into a set of | |
ac0e4fde ML |
631 | predicates. A control dependence chain is represented by a vector |
632 | edges. DEP_CHAINS points to an array of dependence chains. | |
633 | NUM_CHAINS is the size of the chain array. One edge in a dependence | |
927734cf | 634 | chain is mapped to predicate expression represented by pred_info |
ac0e4fde | 635 | type. One dependence chain is converted to a composite predicate that |
927734cf | 636 | is the result of AND operation of pred_info mapped to each edge. |
ac0e4fde | 637 | A composite predicate is presented by a vector of pred_info. On |
34f97b94 XDL |
638 | return, *PREDS points to the resulting array of composite predicates. |
639 | *NUM_PREDS is the number of composite predictes. */ | |
640 | ||
641 | static bool | |
9771b263 | 642 | convert_control_dep_chain_into_preds (vec<edge> *dep_chains, |
5e48d8a0 ML |
643 | size_t num_chains, |
644 | pred_chain_union *preds) | |
34f97b94 XDL |
645 | { |
646 | bool has_valid_pred = false; | |
647 | size_t i, j; | |
648 | if (num_chains == 0 || num_chains >= MAX_NUM_CHAINS) | |
649 | return false; | |
650 | ||
34f97b94 XDL |
651 | /* Now convert the control dep chain into a set |
652 | of predicates. */ | |
927734cf | 653 | preds->reserve (num_chains); |
34f97b94 XDL |
654 | |
655 | for (i = 0; i < num_chains; i++) | |
656 | { | |
9771b263 | 657 | vec<edge> one_cd_chain = dep_chains[i]; |
c375a3a4 DL |
658 | |
659 | has_valid_pred = false; | |
927734cf | 660 | pred_chain t_chain = vNULL; |
9771b263 | 661 | for (j = 0; j < one_cd_chain.length (); j++) |
5e48d8a0 | 662 | { |
355fe088 | 663 | gimple *cond_stmt; |
5e48d8a0 ML |
664 | gimple_stmt_iterator gsi; |
665 | basic_block guard_bb; | |
666 | pred_info one_pred; | |
667 | edge e; | |
668 | ||
669 | e = one_cd_chain[j]; | |
670 | guard_bb = e->src; | |
671 | gsi = gsi_last_bb (guard_bb); | |
e7c6abad | 672 | /* Ignore empty forwarder blocks. */ |
11ef0b22 AH |
673 | if (empty_block_p (guard_bb) && single_succ_p (guard_bb)) |
674 | continue; | |
e7c6abad AH |
675 | /* An empty basic block here is likely a PHI, and is not one |
676 | of the cases we handle below. */ | |
677 | if (gsi_end_p (gsi)) | |
678 | { | |
679 | has_valid_pred = false; | |
680 | break; | |
681 | } | |
5e48d8a0 | 682 | cond_stmt = gsi_stmt (gsi); |
ac0e4fde ML |
683 | if (is_gimple_call (cond_stmt) && EDGE_COUNT (e->src->succs) >= 2) |
684 | /* Ignore EH edge. Can add assertion on the other edge's flag. */ | |
685 | continue; | |
5e48d8a0 ML |
686 | /* Skip if there is essentially one succesor. */ |
687 | if (EDGE_COUNT (e->src->succs) == 2) | |
688 | { | |
689 | edge e1; | |
690 | edge_iterator ei1; | |
691 | bool skip = false; | |
692 | ||
693 | FOR_EACH_EDGE (e1, ei1, e->src->succs) | |
694 | { | |
695 | if (EDGE_COUNT (e1->dest->succs) == 0) | |
696 | { | |
697 | skip = true; | |
698 | break; | |
699 | } | |
700 | } | |
701 | if (skip) | |
702 | continue; | |
703 | } | |
704 | if (gimple_code (cond_stmt) == GIMPLE_COND) | |
666e8e06 RB |
705 | { |
706 | one_pred.pred_lhs = gimple_cond_lhs (cond_stmt); | |
707 | one_pred.pred_rhs = gimple_cond_rhs (cond_stmt); | |
708 | one_pred.cond_code = gimple_cond_code (cond_stmt); | |
709 | one_pred.invert = !!(e->flags & EDGE_FALSE_VALUE); | |
710 | t_chain.safe_push (one_pred); | |
711 | has_valid_pred = true; | |
712 | } | |
ac0e4fde | 713 | else if (gswitch *gs = dyn_cast<gswitch *> (cond_stmt)) |
666e8e06 RB |
714 | { |
715 | /* Avoid quadratic behavior. */ | |
716 | if (gimple_switch_num_labels (gs) > MAX_SWITCH_CASES) | |
717 | { | |
718 | has_valid_pred = false; | |
719 | break; | |
720 | } | |
721 | /* Find the case label. */ | |
722 | tree l = NULL_TREE; | |
723 | unsigned idx; | |
724 | for (idx = 0; idx < gimple_switch_num_labels (gs); ++idx) | |
725 | { | |
726 | tree tl = gimple_switch_label (gs, idx); | |
61ff5d6f | 727 | if (e->dest == label_to_block (cfun, CASE_LABEL (tl))) |
666e8e06 RB |
728 | { |
729 | if (!l) | |
730 | l = tl; | |
731 | else | |
732 | { | |
733 | l = NULL_TREE; | |
734 | break; | |
735 | } | |
736 | } | |
737 | } | |
738 | /* If more than one label reaches this block or the case | |
5e48d8a0 | 739 | label doesn't have a single value (like the default one) |
666e8e06 RB |
740 | fail. */ |
741 | if (!l | |
742 | || !CASE_LOW (l) | |
ac0e4fde ML |
743 | || (CASE_HIGH (l) |
744 | && !operand_equal_p (CASE_LOW (l), CASE_HIGH (l), 0))) | |
666e8e06 RB |
745 | { |
746 | has_valid_pred = false; | |
747 | break; | |
748 | } | |
749 | one_pred.pred_lhs = gimple_switch_index (gs); | |
750 | one_pred.pred_rhs = CASE_LOW (l); | |
751 | one_pred.cond_code = EQ_EXPR; | |
752 | one_pred.invert = false; | |
753 | t_chain.safe_push (one_pred); | |
754 | has_valid_pred = true; | |
755 | } | |
756 | else | |
5e48d8a0 ML |
757 | { |
758 | has_valid_pred = false; | |
759 | break; | |
760 | } | |
761 | } | |
34f97b94 XDL |
762 | |
763 | if (!has_valid_pred) | |
a4f0c29d | 764 | break; |
927734cf | 765 | else |
a4f0c29d | 766 | preds->safe_push (t_chain); |
34f97b94 XDL |
767 | } |
768 | return has_valid_pred; | |
769 | } | |
770 | ||
ac0e4fde | 771 | /* Computes all control dependence chains for USE_BB. The control |
34f97b94 XDL |
772 | dependence chains are then converted to an array of composite |
773 | predicates pointed to by PREDS. PHI_BB is the basic block of | |
774 | the phi whose result is used in USE_BB. */ | |
775 | ||
776 | static bool | |
927734cf | 777 | find_predicates (pred_chain_union *preds, |
5e48d8a0 ML |
778 | basic_block phi_bb, |
779 | basic_block use_bb) | |
34f97b94 XDL |
780 | { |
781 | size_t num_chains = 0, i; | |
92261ce0 JJ |
782 | int num_calls = 0; |
783 | vec<edge> dep_chains[MAX_NUM_CHAINS]; | |
784 | auto_vec<edge, MAX_CHAIN_LEN + 1> cur_chain; | |
34f97b94 XDL |
785 | bool has_valid_pred = false; |
786 | basic_block cd_root = 0; | |
787 | ||
34f97b94 XDL |
788 | /* First find the closest bb that is control equivalent to PHI_BB |
789 | that also dominates USE_BB. */ | |
790 | cd_root = phi_bb; | |
791 | while (dominated_by_p (CDI_DOMINATORS, use_bb, cd_root)) | |
792 | { | |
793 | basic_block ctrl_eq_bb = find_control_equiv_block (cd_root); | |
794 | if (ctrl_eq_bb && dominated_by_p (CDI_DOMINATORS, use_bb, ctrl_eq_bb)) | |
5e48d8a0 | 795 | cd_root = ctrl_eq_bb; |
34f97b94 | 796 | else |
5e48d8a0 | 797 | break; |
34f97b94 XDL |
798 | } |
799 | ||
92261ce0 JJ |
800 | compute_control_dep_chain (cd_root, use_bb, dep_chains, &num_chains, |
801 | &cur_chain, &num_calls); | |
34f97b94 XDL |
802 | |
803 | has_valid_pred | |
92261ce0 | 804 | = convert_control_dep_chain_into_preds (dep_chains, num_chains, preds); |
34f97b94 | 805 | for (i = 0; i < num_chains; i++) |
9771b263 | 806 | dep_chains[i].release (); |
34f97b94 XDL |
807 | return has_valid_pred; |
808 | } | |
809 | ||
810 | /* Computes the set of incoming edges of PHI that have non empty | |
811 | definitions of a phi chain. The collection will be done | |
ac0e4fde ML |
812 | recursively on operands that are defined by phis. CD_ROOT |
813 | is the control dependence root. *EDGES holds the result, and | |
34f97b94 XDL |
814 | VISITED_PHIS is a pointer set for detecting cycles. */ |
815 | ||
816 | static void | |
538dd0b7 | 817 | collect_phi_def_edges (gphi *phi, basic_block cd_root, |
a4f0c29d | 818 | auto_vec<edge> *edges, |
355fe088 | 819 | hash_set<gimple *> *visited_phis) |
34f97b94 XDL |
820 | { |
821 | size_t i, n; | |
822 | edge opnd_edge; | |
823 | tree opnd; | |
824 | ||
6e2830c3 | 825 | if (visited_phis->add (phi)) |
34f97b94 XDL |
826 | return; |
827 | ||
828 | n = gimple_phi_num_args (phi); | |
829 | for (i = 0; i < n; i++) | |
830 | { | |
831 | opnd_edge = gimple_phi_arg_edge (phi, i); | |
832 | opnd = gimple_phi_arg_def (phi, i); | |
833 | ||
e74780a3 | 834 | if (TREE_CODE (opnd) != SSA_NAME) |
5e48d8a0 ML |
835 | { |
836 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
837 | { | |
ac0e4fde | 838 | fprintf (dump_file, "\n[CHECK] Found def edge %d in ", (int) i); |
ef6cb4c7 | 839 | print_gimple_stmt (dump_file, phi, 0); |
5e48d8a0 ML |
840 | } |
841 | edges->safe_push (opnd_edge); | |
842 | } | |
34f97b94 | 843 | else |
5e48d8a0 | 844 | { |
355fe088 | 845 | gimple *def = SSA_NAME_DEF_STMT (opnd); |
e74780a3 | 846 | |
5e48d8a0 | 847 | if (gimple_code (def) == GIMPLE_PHI |
ac0e4fde ML |
848 | && dominated_by_p (CDI_DOMINATORS, gimple_bb (def), cd_root)) |
849 | collect_phi_def_edges (as_a<gphi *> (def), cd_root, edges, | |
5e48d8a0 ML |
850 | visited_phis); |
851 | else if (!uninit_undefined_value_p (opnd)) | |
852 | { | |
853 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
854 | { | |
ac0e4fde ML |
855 | fprintf (dump_file, "\n[CHECK] Found def edge %d in ", |
856 | (int) i); | |
ef6cb4c7 | 857 | print_gimple_stmt (dump_file, phi, 0); |
5e48d8a0 ML |
858 | } |
859 | edges->safe_push (opnd_edge); | |
860 | } | |
861 | } | |
34f97b94 XDL |
862 | } |
863 | } | |
864 | ||
865 | /* For each use edge of PHI, computes all control dependence chains. | |
866 | The control dependence chains are then converted to an array of | |
867 | composite predicates pointed to by PREDS. */ | |
868 | ||
869 | static bool | |
538dd0b7 | 870 | find_def_preds (pred_chain_union *preds, gphi *phi) |
34f97b94 XDL |
871 | { |
872 | size_t num_chains = 0, i, n; | |
92261ce0 JJ |
873 | vec<edge> dep_chains[MAX_NUM_CHAINS]; |
874 | auto_vec<edge, MAX_CHAIN_LEN + 1> cur_chain; | |
a4f0c29d | 875 | auto_vec<edge> def_edges; |
34f97b94 XDL |
876 | bool has_valid_pred = false; |
877 | basic_block phi_bb, cd_root = 0; | |
34f97b94 | 878 | |
34f97b94 XDL |
879 | phi_bb = gimple_bb (phi); |
880 | /* First find the closest dominating bb to be | |
ac0e4fde | 881 | the control dependence root. */ |
34f97b94 XDL |
882 | cd_root = find_dom (phi_bb); |
883 | if (!cd_root) | |
884 | return false; | |
885 | ||
355fe088 | 886 | hash_set<gimple *> visited_phis; |
6e2830c3 | 887 | collect_phi_def_edges (phi, cd_root, &def_edges, &visited_phis); |
34f97b94 | 888 | |
9771b263 | 889 | n = def_edges.length (); |
34f97b94 XDL |
890 | if (n == 0) |
891 | return false; | |
892 | ||
893 | for (i = 0; i < n; i++) | |
894 | { | |
895 | size_t prev_nc, j; | |
92261ce0 | 896 | int num_calls = 0; |
34f97b94 XDL |
897 | edge opnd_edge; |
898 | ||
9771b263 | 899 | opnd_edge = def_edges[i]; |
34f97b94 | 900 | prev_nc = num_chains; |
92261ce0 JJ |
901 | compute_control_dep_chain (cd_root, opnd_edge->src, dep_chains, |
902 | &num_chains, &cur_chain, &num_calls); | |
34f97b94 XDL |
903 | |
904 | /* Now update the newly added chains with | |
5e48d8a0 | 905 | the phi operand edge: */ |
34f97b94 | 906 | if (EDGE_COUNT (opnd_edge->src->succs) > 1) |
5e48d8a0 | 907 | { |
92261ce0 JJ |
908 | if (prev_nc == num_chains && num_chains < MAX_NUM_CHAINS) |
909 | dep_chains[num_chains++] = vNULL; | |
5e48d8a0 | 910 | for (j = prev_nc; j < num_chains; j++) |
92261ce0 | 911 | dep_chains[j].safe_push (opnd_edge); |
5e48d8a0 | 912 | } |
34f97b94 XDL |
913 | } |
914 | ||
915 | has_valid_pred | |
92261ce0 | 916 | = convert_control_dep_chain_into_preds (dep_chains, num_chains, preds); |
34f97b94 | 917 | for (i = 0; i < num_chains; i++) |
9771b263 | 918 | dep_chains[i].release (); |
34f97b94 XDL |
919 | return has_valid_pred; |
920 | } | |
921 | ||
11ef0b22 AH |
922 | /* Dump a pred_info. */ |
923 | ||
924 | static void | |
925 | dump_pred_info (pred_info one_pred) | |
926 | { | |
927 | if (one_pred.invert) | |
928 | fprintf (dump_file, " (.NOT.) "); | |
929 | print_generic_expr (dump_file, one_pred.pred_lhs); | |
930 | fprintf (dump_file, " %s ", op_symbol_code (one_pred.cond_code)); | |
931 | print_generic_expr (dump_file, one_pred.pred_rhs); | |
932 | } | |
933 | ||
934 | /* Dump a pred_chain. */ | |
935 | ||
936 | static void | |
937 | dump_pred_chain (pred_chain one_pred_chain) | |
938 | { | |
939 | size_t np = one_pred_chain.length (); | |
940 | for (size_t j = 0; j < np; j++) | |
941 | { | |
942 | dump_pred_info (one_pred_chain[j]); | |
943 | if (j < np - 1) | |
944 | fprintf (dump_file, " (.AND.) "); | |
945 | else | |
946 | fprintf (dump_file, "\n"); | |
947 | } | |
948 | } | |
949 | ||
34f97b94 XDL |
950 | /* Dumps the predicates (PREDS) for USESTMT. */ |
951 | ||
952 | static void | |
ac0e4fde | 953 | dump_predicates (gimple *usestmt, pred_chain_union preds, const char *msg) |
34f97b94 | 954 | { |
81018dcf | 955 | fprintf (dump_file, "%s", msg); |
11ef0b22 AH |
956 | if (usestmt) |
957 | { | |
958 | print_gimple_stmt (dump_file, usestmt, 0); | |
959 | fprintf (dump_file, "is guarded by :\n\n"); | |
960 | } | |
927734cf | 961 | size_t num_preds = preds.length (); |
11ef0b22 | 962 | for (size_t i = 0; i < num_preds; i++) |
34f97b94 | 963 | { |
11ef0b22 | 964 | dump_pred_chain (preds[i]); |
34f97b94 | 965 | if (i < num_preds - 1) |
5e48d8a0 | 966 | fprintf (dump_file, "(.OR.)\n"); |
927734cf | 967 | else |
5e48d8a0 | 968 | fprintf (dump_file, "\n\n"); |
34f97b94 XDL |
969 | } |
970 | } | |
971 | ||
972 | /* Destroys the predicate set *PREDS. */ | |
973 | ||
974 | static void | |
a4f0c29d | 975 | destroy_predicate_vecs (pred_chain_union *preds) |
34f97b94 | 976 | { |
927734cf XDL |
977 | size_t i; |
978 | ||
a4f0c29d | 979 | size_t n = preds->length (); |
34f97b94 | 980 | for (i = 0; i < n; i++) |
a4f0c29d ML |
981 | (*preds)[i].release (); |
982 | preds->release (); | |
34f97b94 XDL |
983 | } |
984 | ||
927734cf | 985 | /* Computes the 'normalized' conditional code with operand |
34f97b94 XDL |
986 | swapping and condition inversion. */ |
987 | ||
988 | static enum tree_code | |
ac0e4fde | 989 | get_cmp_code (enum tree_code orig_cmp_code, bool swap_cond, bool invert) |
34f97b94 XDL |
990 | { |
991 | enum tree_code tc = orig_cmp_code; | |
992 | ||
993 | if (swap_cond) | |
994 | tc = swap_tree_comparison (orig_cmp_code); | |
995 | if (invert) | |
996 | tc = invert_tree_comparison (tc, false); | |
997 | ||
998 | switch (tc) | |
999 | { | |
1000 | case LT_EXPR: | |
1001 | case LE_EXPR: | |
1002 | case GT_EXPR: | |
1003 | case GE_EXPR: | |
1004 | case EQ_EXPR: | |
1005 | case NE_EXPR: | |
1006 | break; | |
1007 | default: | |
1008 | return ERROR_MARK; | |
1009 | } | |
1010 | return tc; | |
1011 | } | |
1012 | ||
5c1b3334 | 1013 | /* Returns whether VAL CMPC BOUNDARY is true. */ |
34f97b94 XDL |
1014 | |
1015 | static bool | |
1016 | is_value_included_in (tree val, tree boundary, enum tree_code cmpc) | |
1017 | { | |
1018 | bool inverted = false; | |
34f97b94 XDL |
1019 | bool result; |
1020 | ||
1021 | /* Only handle integer constant here. */ | |
ac0e4fde | 1022 | if (TREE_CODE (val) != INTEGER_CST || TREE_CODE (boundary) != INTEGER_CST) |
34f97b94 XDL |
1023 | return true; |
1024 | ||
ac0e4fde | 1025 | if (cmpc == GE_EXPR || cmpc == GT_EXPR || cmpc == NE_EXPR) |
34f97b94 XDL |
1026 | { |
1027 | cmpc = invert_tree_comparison (cmpc, false); | |
1028 | inverted = true; | |
1029 | } | |
1030 | ||
fb4b60c6 VI |
1031 | if (cmpc == EQ_EXPR) |
1032 | result = tree_int_cst_equal (val, boundary); | |
1033 | else if (cmpc == LT_EXPR) | |
1034 | result = tree_int_cst_lt (val, boundary); | |
34f97b94 XDL |
1035 | else |
1036 | { | |
fb4b60c6 VI |
1037 | gcc_assert (cmpc == LE_EXPR); |
1038 | result = tree_int_cst_le (val, boundary); | |
34f97b94 XDL |
1039 | } |
1040 | ||
1041 | if (inverted) | |
1042 | result ^= 1; | |
1043 | ||
1044 | return result; | |
1045 | } | |
1046 | ||
0f8e84c6 VI |
1047 | /* Returns whether VAL satisfies (x CMPC BOUNDARY) predicate. CMPC can be |
1048 | either one of the range comparison codes ({GE,LT,EQ,NE}_EXPR and the like), | |
1049 | or BIT_AND_EXPR. EXACT_P is only meaningful for the latter. It modifies the | |
1050 | question from whether VAL & BOUNDARY != 0 to whether VAL & BOUNDARY == VAL. | |
1051 | For other values of CMPC, EXACT_P is ignored. */ | |
1052 | ||
1053 | static bool | |
1054 | value_sat_pred_p (tree val, tree boundary, enum tree_code cmpc, | |
1055 | bool exact_p = false) | |
1056 | { | |
1057 | if (cmpc != BIT_AND_EXPR) | |
1058 | return is_value_included_in (val, boundary, cmpc); | |
1059 | ||
56a4e074 | 1060 | wide_int andw = wi::to_wide (val) & wi::to_wide (boundary); |
0f8e84c6 VI |
1061 | if (exact_p) |
1062 | return andw == wi::to_wide (val); | |
1063 | else | |
1064 | return andw.to_uhwi (); | |
1065 | } | |
1066 | ||
34f97b94 XDL |
1067 | /* Returns true if PRED is common among all the predicate |
1068 | chains (PREDS) (and therefore can be factored out). | |
1069 | NUM_PRED_CHAIN is the size of array PREDS. */ | |
1070 | ||
1071 | static bool | |
927734cf | 1072 | find_matching_predicate_in_rest_chains (pred_info pred, |
5e48d8a0 ML |
1073 | pred_chain_union preds, |
1074 | size_t num_pred_chains) | |
34f97b94 XDL |
1075 | { |
1076 | size_t i, j, n; | |
1077 | ||
927734cf | 1078 | /* Trival case. */ |
34f97b94 XDL |
1079 | if (num_pred_chains == 1) |
1080 | return true; | |
1081 | ||
1082 | for (i = 1; i < num_pred_chains; i++) | |
1083 | { | |
1084 | bool found = false; | |
927734cf | 1085 | pred_chain one_chain = preds[i]; |
9771b263 | 1086 | n = one_chain.length (); |
34f97b94 | 1087 | for (j = 0; j < n; j++) |
5e48d8a0 ML |
1088 | { |
1089 | pred_info pred2 = one_chain[j]; | |
1090 | /* Can relax the condition comparison to not | |
ac0e4fde | 1091 | use address comparison. However, the most common |
5e48d8a0 ML |
1092 | case is that multiple control dependent paths share |
1093 | a common path prefix, so address comparison should | |
1094 | be ok. */ | |
1095 | ||
1096 | if (operand_equal_p (pred2.pred_lhs, pred.pred_lhs, 0) | |
1097 | && operand_equal_p (pred2.pred_rhs, pred.pred_rhs, 0) | |
1098 | && pred2.invert == pred.invert) | |
1099 | { | |
1100 | found = true; | |
1101 | break; | |
1102 | } | |
1103 | } | |
34f97b94 | 1104 | if (!found) |
5e48d8a0 | 1105 | return false; |
34f97b94 XDL |
1106 | } |
1107 | return true; | |
1108 | } | |
1109 | ||
1110 | /* Forward declaration. */ | |
ac0e4fde ML |
1111 | static bool is_use_properly_guarded (gimple *use_stmt, |
1112 | basic_block use_bb, | |
1113 | gphi *phi, | |
1114 | unsigned uninit_opnds, | |
1115 | pred_chain_union *def_preds, | |
1116 | hash_set<gphi *> *visited_phis); | |
1117 | ||
1118 | /* Returns true if all uninitialized opnds are pruned. Returns false | |
1119 | otherwise. PHI is the phi node with uninitialized operands, | |
2edb37a6 XDL |
1120 | UNINIT_OPNDS is the bitmap of the uninitialize operand positions, |
1121 | FLAG_DEF is the statement defining the flag guarding the use of the | |
1122 | PHI output, BOUNDARY_CST is the const value used in the predicate | |
1123 | associated with the flag, CMP_CODE is the comparison code used in | |
1124 | the predicate, VISITED_PHIS is the pointer set of phis visited, and | |
1125 | VISITED_FLAG_PHIS is the pointer to the pointer set of flag definitions | |
1126 | that are also phis. | |
1127 | ||
1128 | Example scenario: | |
1129 | ||
1130 | BB1: | |
ac0e4fde | 1131 | flag_1 = phi <0, 1> // (1) |
2edb37a6 XDL |
1132 | var_1 = phi <undef, some_val> |
1133 | ||
1134 | ||
1135 | BB2: | |
1136 | flag_2 = phi <0, flag_1, flag_1> // (2) | |
1137 | var_2 = phi <undef, var_1, var_1> | |
1138 | if (flag_2 == 1) | |
1139 | goto BB3; | |
1140 | ||
1141 | BB3: | |
ac0e4fde | 1142 | use of var_2 // (3) |
2edb37a6 XDL |
1143 | |
1144 | Because some flag arg in (1) is not constant, if we do not look into the | |
1145 | flag phis recursively, it is conservatively treated as unknown and var_1 | |
ac0e4fde ML |
1146 | is thought to be flowed into use at (3). Since var_1 is potentially |
1147 | uninitialized a false warning will be emitted. | |
1148 | Checking recursively into (1), the compiler can find out that only some_val | |
1149 | (which is defined) can flow into (3) which is OK. */ | |
2edb37a6 XDL |
1150 | |
1151 | static bool | |
ac0e4fde ML |
1152 | prune_uninit_phi_opnds (gphi *phi, unsigned uninit_opnds, gphi *flag_def, |
1153 | tree boundary_cst, enum tree_code cmp_code, | |
1154 | hash_set<gphi *> *visited_phis, | |
1155 | bitmap *visited_flag_phis) | |
2edb37a6 XDL |
1156 | { |
1157 | unsigned i; | |
1158 | ||
358a95e4 | 1159 | for (i = 0; i < MIN (max_phi_args, gimple_phi_num_args (flag_def)); i++) |
2edb37a6 XDL |
1160 | { |
1161 | tree flag_arg; | |
1162 | ||
1163 | if (!MASK_TEST_BIT (uninit_opnds, i)) | |
5e48d8a0 | 1164 | continue; |
2edb37a6 XDL |
1165 | |
1166 | flag_arg = gimple_phi_arg_def (flag_def, i); | |
1167 | if (!is_gimple_constant (flag_arg)) | |
5e48d8a0 ML |
1168 | { |
1169 | gphi *flag_arg_def, *phi_arg_def; | |
1170 | tree phi_arg; | |
1171 | unsigned uninit_opnds_arg_phi; | |
1172 | ||
1173 | if (TREE_CODE (flag_arg) != SSA_NAME) | |
1174 | return false; | |
ac0e4fde | 1175 | flag_arg_def = dyn_cast<gphi *> (SSA_NAME_DEF_STMT (flag_arg)); |
538dd0b7 | 1176 | if (!flag_arg_def) |
5e48d8a0 | 1177 | return false; |
2edb37a6 | 1178 | |
5e48d8a0 ML |
1179 | phi_arg = gimple_phi_arg_def (phi, i); |
1180 | if (TREE_CODE (phi_arg) != SSA_NAME) | |
1181 | return false; | |
2edb37a6 | 1182 | |
ac0e4fde | 1183 | phi_arg_def = dyn_cast<gphi *> (SSA_NAME_DEF_STMT (phi_arg)); |
538dd0b7 | 1184 | if (!phi_arg_def) |
5e48d8a0 | 1185 | return false; |
2edb37a6 | 1186 | |
5e48d8a0 ML |
1187 | if (gimple_bb (phi_arg_def) != gimple_bb (flag_arg_def)) |
1188 | return false; | |
2edb37a6 | 1189 | |
5e48d8a0 ML |
1190 | if (!*visited_flag_phis) |
1191 | *visited_flag_phis = BITMAP_ALLOC (NULL); | |
2edb37a6 | 1192 | |
ac0e4fde ML |
1193 | tree phi_result = gimple_phi_result (flag_arg_def); |
1194 | if (bitmap_bit_p (*visited_flag_phis, SSA_NAME_VERSION (phi_result))) | |
5e48d8a0 | 1195 | return false; |
2edb37a6 | 1196 | |
5e48d8a0 ML |
1197 | bitmap_set_bit (*visited_flag_phis, |
1198 | SSA_NAME_VERSION (gimple_phi_result (flag_arg_def))); | |
2edb37a6 | 1199 | |
5e48d8a0 ML |
1200 | /* Now recursively prune the uninitialized phi args. */ |
1201 | uninit_opnds_arg_phi = compute_uninit_opnds_pos (phi_arg_def); | |
ac0e4fde ML |
1202 | if (!prune_uninit_phi_opnds |
1203 | (phi_arg_def, uninit_opnds_arg_phi, flag_arg_def, boundary_cst, | |
1204 | cmp_code, visited_phis, visited_flag_phis)) | |
5e48d8a0 | 1205 | return false; |
2edb37a6 | 1206 | |
ac0e4fde ML |
1207 | phi_result = gimple_phi_result (flag_arg_def); |
1208 | bitmap_clear_bit (*visited_flag_phis, SSA_NAME_VERSION (phi_result)); | |
5e48d8a0 ML |
1209 | continue; |
1210 | } | |
2edb37a6 XDL |
1211 | |
1212 | /* Now check if the constant is in the guarded range. */ | |
1213 | if (is_value_included_in (flag_arg, boundary_cst, cmp_code)) | |
5e48d8a0 ML |
1214 | { |
1215 | tree opnd; | |
355fe088 | 1216 | gimple *opnd_def; |
2edb37a6 | 1217 | |
5e48d8a0 | 1218 | /* Now that we know that this undefined edge is not |
ac0e4fde | 1219 | pruned. If the operand is defined by another phi, |
5e48d8a0 ML |
1220 | we can further prune the incoming edges of that |
1221 | phi by checking the predicates of this operands. */ | |
1222 | ||
1223 | opnd = gimple_phi_arg_def (phi, i); | |
1224 | opnd_def = SSA_NAME_DEF_STMT (opnd); | |
1225 | if (gphi *opnd_def_phi = dyn_cast <gphi *> (opnd_def)) | |
1226 | { | |
1227 | edge opnd_edge; | |
ac0e4fde | 1228 | unsigned uninit_opnds2 = compute_uninit_opnds_pos (opnd_def_phi); |
8bc47ae2 RB |
1229 | if (!MASK_EMPTY (uninit_opnds2)) |
1230 | { | |
1231 | pred_chain_union def_preds = vNULL; | |
1232 | bool ok; | |
1233 | opnd_edge = gimple_phi_arg_edge (phi, i); | |
1234 | ok = is_use_properly_guarded (phi, | |
1235 | opnd_edge->src, | |
1236 | opnd_def_phi, | |
1237 | uninit_opnds2, | |
1238 | &def_preds, | |
1239 | visited_phis); | |
1240 | destroy_predicate_vecs (&def_preds); | |
1241 | if (!ok) | |
1242 | return false; | |
1243 | } | |
5e48d8a0 ML |
1244 | } |
1245 | else | |
1246 | return false; | |
1247 | } | |
2edb37a6 XDL |
1248 | } |
1249 | ||
1250 | return true; | |
1251 | } | |
1252 | ||
34f97b94 XDL |
1253 | /* A helper function that determines if the predicate set |
1254 | of the use is not overlapping with that of the uninit paths. | |
1255 | The most common senario of guarded use is in Example 1: | |
1256 | Example 1: | |
5e48d8a0 ML |
1257 | if (some_cond) |
1258 | { | |
1259 | x = ...; | |
1260 | flag = true; | |
1261 | } | |
34f97b94 | 1262 | |
5e48d8a0 | 1263 | ... some code ... |
34f97b94 | 1264 | |
5e48d8a0 ML |
1265 | if (flag) |
1266 | use (x); | |
34f97b94 XDL |
1267 | |
1268 | The real world examples are usually more complicated, but similar | |
1269 | and usually result from inlining: | |
1270 | ||
5e48d8a0 ML |
1271 | bool init_func (int * x) |
1272 | { | |
1273 | if (some_cond) | |
1274 | return false; | |
1275 | *x = .. | |
1276 | return true; | |
1277 | } | |
34f97b94 | 1278 | |
ac0e4fde | 1279 | void foo (..) |
5e48d8a0 ML |
1280 | { |
1281 | int x; | |
34f97b94 | 1282 | |
ac0e4fde | 1283 | if (!init_func (&x)) |
5e48d8a0 | 1284 | return; |
34f97b94 | 1285 | |
5e48d8a0 ML |
1286 | .. some_code ... |
1287 | use (x); | |
1288 | } | |
34f97b94 XDL |
1289 | |
1290 | Another possible use scenario is in the following trivial example: | |
1291 | ||
1292 | Example 2: | |
5e48d8a0 ML |
1293 | if (n > 0) |
1294 | x = 1; | |
1295 | ... | |
1296 | if (n > 0) | |
1297 | { | |
1298 | if (m < 2) | |
1299 | .. = x; | |
1300 | } | |
34f97b94 XDL |
1301 | |
1302 | Predicate analysis needs to compute the composite predicate: | |
1303 | ||
1304 | 1) 'x' use predicate: (n > 0) .AND. (m < 2) | |
1305 | 2) 'x' default value (non-def) predicate: .NOT. (n > 0) | |
1306 | (the predicate chain for phi operand defs can be computed | |
1307 | starting from a bb that is control equivalent to the phi's | |
1308 | bb and is dominating the operand def.) | |
1309 | ||
1310 | and check overlapping: | |
5e48d8a0 ML |
1311 | (n > 0) .AND. (m < 2) .AND. (.NOT. (n > 0)) |
1312 | <==> false | |
34f97b94 XDL |
1313 | |
1314 | This implementation provides framework that can handle | |
ac0e4fde | 1315 | scenarios. (Note that many simple cases are handled properly |
34f97b94 XDL |
1316 | without the predicate analysis -- this is due to jump threading |
1317 | transformation which eliminates the merge point thus makes | |
1318 | path sensitive analysis unnecessary.) | |
1319 | ||
358a95e4 AH |
1320 | PHI is the phi node whose incoming (undefined) paths need to be |
1321 | pruned, and UNINIT_OPNDS is the bitmap holding uninit operand | |
1322 | positions. VISITED_PHIS is the pointer set of phi stmts being | |
1323 | checked. */ | |
34f97b94 | 1324 | |
34f97b94 | 1325 | static bool |
927734cf | 1326 | use_pred_not_overlap_with_undef_path_pred (pred_chain_union preds, |
5e48d8a0 | 1327 | gphi *phi, unsigned uninit_opnds, |
538dd0b7 | 1328 | hash_set<gphi *> *visited_phis) |
34f97b94 XDL |
1329 | { |
1330 | unsigned int i, n; | |
355fe088 | 1331 | gimple *flag_def = 0; |
ac0e4fde | 1332 | tree boundary_cst = 0; |
34f97b94 XDL |
1333 | enum tree_code cmp_code; |
1334 | bool swap_cond = false; | |
1335 | bool invert = false; | |
927734cf | 1336 | pred_chain the_pred_chain = vNULL; |
2edb37a6 XDL |
1337 | bitmap visited_flag_phis = NULL; |
1338 | bool all_pruned = false; | |
927734cf | 1339 | size_t num_preds = preds.length (); |
34f97b94 XDL |
1340 | |
1341 | gcc_assert (num_preds > 0); | |
1342 | /* Find within the common prefix of multiple predicate chains | |
1343 | a predicate that is a comparison of a flag variable against | |
1344 | a constant. */ | |
1345 | the_pred_chain = preds[0]; | |
9771b263 | 1346 | n = the_pred_chain.length (); |
34f97b94 XDL |
1347 | for (i = 0; i < n; i++) |
1348 | { | |
34f97b94 XDL |
1349 | tree cond_lhs, cond_rhs, flag = 0; |
1350 | ||
927734cf | 1351 | pred_info the_pred = the_pred_chain[i]; |
34f97b94 | 1352 | |
927734cf XDL |
1353 | invert = the_pred.invert; |
1354 | cond_lhs = the_pred.pred_lhs; | |
1355 | cond_rhs = the_pred.pred_rhs; | |
1356 | cmp_code = the_pred.cond_code; | |
34f97b94 XDL |
1357 | |
1358 | if (cond_lhs != NULL_TREE && TREE_CODE (cond_lhs) == SSA_NAME | |
5e48d8a0 ML |
1359 | && cond_rhs != NULL_TREE && is_gimple_constant (cond_rhs)) |
1360 | { | |
1361 | boundary_cst = cond_rhs; | |
1362 | flag = cond_lhs; | |
1363 | } | |
34f97b94 | 1364 | else if (cond_rhs != NULL_TREE && TREE_CODE (cond_rhs) == SSA_NAME |
5e48d8a0 ML |
1365 | && cond_lhs != NULL_TREE && is_gimple_constant (cond_lhs)) |
1366 | { | |
1367 | boundary_cst = cond_lhs; | |
1368 | flag = cond_rhs; | |
1369 | swap_cond = true; | |
1370 | } | |
34f97b94 XDL |
1371 | |
1372 | if (!flag) | |
5e48d8a0 | 1373 | continue; |
34f97b94 XDL |
1374 | |
1375 | flag_def = SSA_NAME_DEF_STMT (flag); | |
1376 | ||
1377 | if (!flag_def) | |
5e48d8a0 | 1378 | continue; |
34f97b94 XDL |
1379 | |
1380 | if ((gimple_code (flag_def) == GIMPLE_PHI) | |
5e48d8a0 ML |
1381 | && (gimple_bb (flag_def) == gimple_bb (phi)) |
1382 | && find_matching_predicate_in_rest_chains (the_pred, preds, | |
927734cf | 1383 | num_preds)) |
5e48d8a0 | 1384 | break; |
34f97b94 XDL |
1385 | |
1386 | flag_def = 0; | |
1387 | } | |
1388 | ||
1389 | if (!flag_def) | |
1390 | return false; | |
1391 | ||
1392 | /* Now check all the uninit incoming edge has a constant flag value | |
1393 | that is in conflict with the use guard/predicate. */ | |
1394 | cmp_code = get_cmp_code (cmp_code, swap_cond, invert); | |
1395 | ||
1396 | if (cmp_code == ERROR_MARK) | |
1397 | return false; | |
1398 | ||
ac0e4fde ML |
1399 | all_pruned = prune_uninit_phi_opnds |
1400 | (phi, uninit_opnds, as_a<gphi *> (flag_def), boundary_cst, cmp_code, | |
1401 | visited_phis, &visited_flag_phis); | |
34f97b94 | 1402 | |
2edb37a6 XDL |
1403 | if (visited_flag_phis) |
1404 | BITMAP_FREE (visited_flag_phis); | |
34f97b94 | 1405 | |
2edb37a6 | 1406 | return all_pruned; |
34f97b94 XDL |
1407 | } |
1408 | ||
927734cf | 1409 | /* The helper function returns true if two predicates X1 and X2 |
ac0e4fde | 1410 | are equivalent. It assumes the expressions have already |
927734cf | 1411 | properly re-associated. */ |
34f97b94 XDL |
1412 | |
1413 | static inline bool | |
927734cf | 1414 | pred_equal_p (pred_info x1, pred_info x2) |
34f97b94 | 1415 | { |
927734cf XDL |
1416 | enum tree_code c1, c2; |
1417 | if (!operand_equal_p (x1.pred_lhs, x2.pred_lhs, 0) | |
1418 | || !operand_equal_p (x1.pred_rhs, x2.pred_rhs, 0)) | |
1419 | return false; | |
34f97b94 | 1420 | |
927734cf | 1421 | c1 = x1.cond_code; |
c27348aa MP |
1422 | if (x1.invert != x2.invert |
1423 | && TREE_CODE_CLASS (x2.cond_code) == tcc_comparison) | |
927734cf XDL |
1424 | c2 = invert_tree_comparison (x2.cond_code, false); |
1425 | else | |
1426 | c2 = x2.cond_code; | |
34f97b94 | 1427 | |
927734cf XDL |
1428 | return c1 == c2; |
1429 | } | |
34f97b94 | 1430 | |
927734cf | 1431 | /* Returns true if the predication is testing !=. */ |
34f97b94 | 1432 | |
927734cf XDL |
1433 | static inline bool |
1434 | is_neq_relop_p (pred_info pred) | |
34f97b94 | 1435 | { |
34f97b94 | 1436 | |
ac0e4fde ML |
1437 | return ((pred.cond_code == NE_EXPR && !pred.invert) |
1438 | || (pred.cond_code == EQ_EXPR && pred.invert)); | |
34f97b94 XDL |
1439 | } |
1440 | ||
927734cf | 1441 | /* Returns true if pred is of the form X != 0. */ |
34f97b94 | 1442 | |
5e48d8a0 | 1443 | static inline bool |
927734cf | 1444 | is_neq_zero_form_p (pred_info pred) |
34f97b94 | 1445 | { |
927734cf XDL |
1446 | if (!is_neq_relop_p (pred) || !integer_zerop (pred.pred_rhs) |
1447 | || TREE_CODE (pred.pred_lhs) != SSA_NAME) | |
1448 | return false; | |
1449 | return true; | |
1450 | } | |
34f97b94 | 1451 | |
927734cf XDL |
1452 | /* The helper function returns true if two predicates X1 |
1453 | is equivalent to X2 != 0. */ | |
34f97b94 | 1454 | |
927734cf XDL |
1455 | static inline bool |
1456 | pred_expr_equal_p (pred_info x1, tree x2) | |
1457 | { | |
1458 | if (!is_neq_zero_form_p (x1)) | |
1459 | return false; | |
34f97b94 | 1460 | |
927734cf | 1461 | return operand_equal_p (x1.pred_lhs, x2, 0); |
34f97b94 XDL |
1462 | } |
1463 | ||
927734cf | 1464 | /* Returns true of the domain of single predicate expression |
ac0e4fde | 1465 | EXPR1 is a subset of that of EXPR2. Returns false if it |
67914693 | 1466 | cannot be proved. */ |
34f97b94 XDL |
1467 | |
1468 | static bool | |
927734cf | 1469 | is_pred_expr_subset_of (pred_info expr1, pred_info expr2) |
34f97b94 | 1470 | { |
927734cf | 1471 | enum tree_code code1, code2; |
34f97b94 | 1472 | |
927734cf | 1473 | if (pred_equal_p (expr1, expr2)) |
34f97b94 XDL |
1474 | return true; |
1475 | ||
927734cf XDL |
1476 | if ((TREE_CODE (expr1.pred_rhs) != INTEGER_CST) |
1477 | || (TREE_CODE (expr2.pred_rhs) != INTEGER_CST)) | |
1478 | return false; | |
34f97b94 | 1479 | |
927734cf XDL |
1480 | if (!operand_equal_p (expr1.pred_lhs, expr2.pred_lhs, 0)) |
1481 | return false; | |
34f97b94 | 1482 | |
927734cf XDL |
1483 | code1 = expr1.cond_code; |
1484 | if (expr1.invert) | |
1485 | code1 = invert_tree_comparison (code1, false); | |
1486 | code2 = expr2.cond_code; | |
1487 | if (expr2.invert) | |
1488 | code2 = invert_tree_comparison (code2, false); | |
34f97b94 | 1489 | |
5c1b3334 VI |
1490 | if (code2 == NE_EXPR && code1 == NE_EXPR) |
1491 | return false; | |
1492 | ||
0f8e84c6 VI |
1493 | if (code2 == NE_EXPR) |
1494 | return !value_sat_pred_p (expr2.pred_rhs, expr1.pred_rhs, code1); | |
5c1b3334 | 1495 | |
0f8e84c6 VI |
1496 | if (code1 == EQ_EXPR) |
1497 | return value_sat_pred_p (expr1.pred_rhs, expr2.pred_rhs, code2); | |
666e8e06 | 1498 | |
0f8e84c6 VI |
1499 | if (code1 == code2) |
1500 | return value_sat_pred_p (expr1.pred_rhs, expr2.pred_rhs, code2, | |
1501 | code1 == BIT_AND_EXPR); | |
34f97b94 | 1502 | |
927734cf XDL |
1503 | return false; |
1504 | } | |
34f97b94 | 1505 | |
927734cf | 1506 | /* Returns true if the domain of PRED1 is a subset |
67914693 | 1507 | of that of PRED2. Returns false if it cannot be proved so. */ |
34f97b94 | 1508 | |
927734cf | 1509 | static bool |
ac0e4fde | 1510 | is_pred_chain_subset_of (pred_chain pred1, pred_chain pred2) |
927734cf XDL |
1511 | { |
1512 | size_t np1, np2, i1, i2; | |
34f97b94 | 1513 | |
927734cf XDL |
1514 | np1 = pred1.length (); |
1515 | np2 = pred2.length (); | |
34f97b94 | 1516 | |
927734cf | 1517 | for (i2 = 0; i2 < np2; i2++) |
34f97b94 | 1518 | { |
927734cf XDL |
1519 | bool found = false; |
1520 | pred_info info2 = pred2[i2]; | |
1521 | for (i1 = 0; i1 < np1; i1++) | |
5e48d8a0 ML |
1522 | { |
1523 | pred_info info1 = pred1[i1]; | |
1524 | if (is_pred_expr_subset_of (info1, info2)) | |
1525 | { | |
1526 | found = true; | |
1527 | break; | |
1528 | } | |
1529 | } | |
927734cf | 1530 | if (!found) |
5e48d8a0 | 1531 | return false; |
34f97b94 | 1532 | } |
927734cf | 1533 | return true; |
34f97b94 XDL |
1534 | } |
1535 | ||
927734cf XDL |
1536 | /* Returns true if the domain defined by |
1537 | one pred chain ONE_PRED is a subset of the domain | |
ac0e4fde | 1538 | of *PREDS. It returns false if ONE_PRED's domain is |
927734cf XDL |
1539 | not a subset of any of the sub-domains of PREDS |
1540 | (corresponding to each individual chains in it), even | |
1541 | though it may be still be a subset of whole domain | |
1542 | of PREDS which is the union (ORed) of all its subdomains. | |
1543 | In other words, the result is conservative. */ | |
34f97b94 XDL |
1544 | |
1545 | static bool | |
927734cf | 1546 | is_included_in (pred_chain one_pred, pred_chain_union preds) |
34f97b94 XDL |
1547 | { |
1548 | size_t i; | |
927734cf | 1549 | size_t n = preds.length (); |
34f97b94 | 1550 | |
927734cf | 1551 | for (i = 0; i < n; i++) |
34f97b94 | 1552 | { |
927734cf | 1553 | if (is_pred_chain_subset_of (one_pred, preds[i])) |
5e48d8a0 | 1554 | return true; |
34f97b94 | 1555 | } |
927734cf | 1556 | |
34f97b94 XDL |
1557 | return false; |
1558 | } | |
1559 | ||
927734cf XDL |
1560 | /* Compares two predicate sets PREDS1 and PREDS2 and returns |
1561 | true if the domain defined by PREDS1 is a superset | |
ac0e4fde ML |
1562 | of PREDS2's domain. N1 and N2 are array sizes of PREDS1 and |
1563 | PREDS2 respectively. The implementation chooses not to build | |
927734cf XDL |
1564 | generic trees (and relying on the folding capability of the |
1565 | compiler), but instead performs brute force comparison of | |
1566 | individual predicate chains (won't be a compile time problem | |
ac0e4fde | 1567 | as the chains are pretty short). When the function returns |
927734cf | 1568 | false, it does not necessarily mean *PREDS1 is not a superset |
155ed511 SL |
1569 | of *PREDS2, but mean it may not be so since the analysis cannot |
1570 | prove it. In such cases, false warnings may still be | |
927734cf | 1571 | emitted. */ |
34f97b94 XDL |
1572 | |
1573 | static bool | |
927734cf | 1574 | is_superset_of (pred_chain_union preds1, pred_chain_union preds2) |
34f97b94 | 1575 | { |
927734cf XDL |
1576 | size_t i, n2; |
1577 | pred_chain one_pred_chain = vNULL; | |
34f97b94 | 1578 | |
927734cf XDL |
1579 | n2 = preds2.length (); |
1580 | ||
1581 | for (i = 0; i < n2; i++) | |
34f97b94 | 1582 | { |
927734cf XDL |
1583 | one_pred_chain = preds2[i]; |
1584 | if (!is_included_in (one_pred_chain, preds1)) | |
5e48d8a0 | 1585 | return false; |
34f97b94 | 1586 | } |
927734cf | 1587 | |
34f97b94 XDL |
1588 | return true; |
1589 | } | |
1590 | ||
927734cf XDL |
1591 | /* Returns true if X1 is the negate of X2. */ |
1592 | ||
1593 | static inline bool | |
1594 | pred_neg_p (pred_info x1, pred_info x2) | |
1595 | { | |
1596 | enum tree_code c1, c2; | |
1597 | if (!operand_equal_p (x1.pred_lhs, x2.pred_lhs, 0) | |
1598 | || !operand_equal_p (x1.pred_rhs, x2.pred_rhs, 0)) | |
1599 | return false; | |
5e48d8a0 | 1600 | |
927734cf XDL |
1601 | c1 = x1.cond_code; |
1602 | if (x1.invert == x2.invert) | |
1603 | c2 = invert_tree_comparison (x2.cond_code, false); | |
1604 | else | |
1605 | c2 = x2.cond_code; | |
1606 | ||
1607 | return c1 == c2; | |
34f97b94 XDL |
1608 | } |
1609 | ||
927734cf XDL |
1610 | /* 1) ((x IOR y) != 0) AND (x != 0) is equivalent to (x != 0); |
1611 | 2) (X AND Y) OR (!X AND Y) is equivalent to Y; | |
1612 | 3) X OR (!X AND Y) is equivalent to (X OR Y); | |
1613 | 4) ((x IAND y) != 0) || (x != 0 AND y != 0)) is equivalent to | |
1614 | (x != 0 AND y != 0) | |
1615 | 5) (X AND Y) OR (!X AND Z) OR (!Y AND Z) is equivalent to | |
5e48d8a0 | 1616 | (X AND Y) OR Z |
34f97b94 | 1617 | |
927734cf XDL |
1618 | PREDS is the predicate chains, and N is the number of chains. */ |
1619 | ||
1620 | /* Helper function to implement rule 1 above. ONE_CHAIN is | |
1621 | the AND predication to be simplified. */ | |
1622 | ||
1623 | static void | |
1624 | simplify_pred (pred_chain *one_chain) | |
34f97b94 | 1625 | { |
927734cf XDL |
1626 | size_t i, j, n; |
1627 | bool simplified = false; | |
1628 | pred_chain s_chain = vNULL; | |
34f97b94 | 1629 | |
927734cf | 1630 | n = one_chain->length (); |
34f97b94 | 1631 | |
927734cf | 1632 | for (i = 0; i < n; i++) |
34f97b94 | 1633 | { |
927734cf XDL |
1634 | pred_info *a_pred = &(*one_chain)[i]; |
1635 | ||
1636 | if (!a_pred->pred_lhs) | |
5e48d8a0 | 1637 | continue; |
927734cf | 1638 | if (!is_neq_zero_form_p (*a_pred)) |
5e48d8a0 | 1639 | continue; |
927734cf | 1640 | |
355fe088 | 1641 | gimple *def_stmt = SSA_NAME_DEF_STMT (a_pred->pred_lhs); |
927734cf | 1642 | if (gimple_code (def_stmt) != GIMPLE_ASSIGN) |
5e48d8a0 | 1643 | continue; |
927734cf | 1644 | if (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR) |
5e48d8a0 ML |
1645 | { |
1646 | for (j = 0; j < n; j++) | |
1647 | { | |
1648 | pred_info *b_pred = &(*one_chain)[j]; | |
1649 | ||
1650 | if (!b_pred->pred_lhs) | |
1651 | continue; | |
1652 | if (!is_neq_zero_form_p (*b_pred)) | |
1653 | continue; | |
1654 | ||
1655 | if (pred_expr_equal_p (*b_pred, gimple_assign_rhs1 (def_stmt)) | |
1656 | || pred_expr_equal_p (*b_pred, gimple_assign_rhs2 (def_stmt))) | |
ac0e4fde ML |
1657 | { |
1658 | /* Mark a_pred for removal. */ | |
1659 | a_pred->pred_lhs = NULL; | |
1660 | a_pred->pred_rhs = NULL; | |
1661 | simplified = true; | |
1662 | break; | |
1663 | } | |
5e48d8a0 ML |
1664 | } |
1665 | } | |
34f97b94 | 1666 | } |
34f97b94 | 1667 | |
927734cf | 1668 | if (!simplified) |
ac0e4fde | 1669 | return; |
34f97b94 | 1670 | |
927734cf XDL |
1671 | for (i = 0; i < n; i++) |
1672 | { | |
1673 | pred_info *a_pred = &(*one_chain)[i]; | |
1674 | if (!a_pred->pred_lhs) | |
5e48d8a0 | 1675 | continue; |
927734cf | 1676 | s_chain.safe_push (*a_pred); |
34f97b94 | 1677 | } |
927734cf | 1678 | |
ac0e4fde ML |
1679 | one_chain->release (); |
1680 | *one_chain = s_chain; | |
34f97b94 XDL |
1681 | } |
1682 | ||
927734cf XDL |
1683 | /* The helper function implements the rule 2 for the |
1684 | OR predicate PREDS. | |
1685 | ||
1686 | 2) (X AND Y) OR (!X AND Y) is equivalent to Y. */ | |
34f97b94 XDL |
1687 | |
1688 | static bool | |
927734cf | 1689 | simplify_preds_2 (pred_chain_union *preds) |
34f97b94 | 1690 | { |
927734cf XDL |
1691 | size_t i, j, n; |
1692 | bool simplified = false; | |
1693 | pred_chain_union s_preds = vNULL; | |
34f97b94 | 1694 | |
5e48d8a0 | 1695 | /* (X AND Y) OR (!X AND Y) is equivalent to Y. |
927734cf | 1696 | (X AND Y) OR (X AND !Y) is equivalent to X. */ |
34f97b94 | 1697 | |
927734cf XDL |
1698 | n = preds->length (); |
1699 | for (i = 0; i < n; i++) | |
1700 | { | |
1701 | pred_info x, y; | |
1702 | pred_chain *a_chain = &(*preds)[i]; | |
34f97b94 | 1703 | |
927734cf | 1704 | if (a_chain->length () != 2) |
5e48d8a0 | 1705 | continue; |
927734cf XDL |
1706 | |
1707 | x = (*a_chain)[0]; | |
1708 | y = (*a_chain)[1]; | |
1709 | ||
1710 | for (j = 0; j < n; j++) | |
5e48d8a0 ML |
1711 | { |
1712 | pred_chain *b_chain; | |
1713 | pred_info x2, y2; | |
1714 | ||
1715 | if (j == i) | |
1716 | continue; | |
1717 | ||
1718 | b_chain = &(*preds)[j]; | |
1719 | if (b_chain->length () != 2) | |
1720 | continue; | |
1721 | ||
1722 | x2 = (*b_chain)[0]; | |
1723 | y2 = (*b_chain)[1]; | |
1724 | ||
1725 | if (pred_equal_p (x, x2) && pred_neg_p (y, y2)) | |
1726 | { | |
1727 | /* Kill a_chain. */ | |
1728 | a_chain->release (); | |
1729 | b_chain->release (); | |
1730 | b_chain->safe_push (x); | |
1731 | simplified = true; | |
1732 | break; | |
1733 | } | |
1734 | if (pred_neg_p (x, x2) && pred_equal_p (y, y2)) | |
1735 | { | |
1736 | /* Kill a_chain. */ | |
1737 | a_chain->release (); | |
1738 | b_chain->release (); | |
1739 | b_chain->safe_push (y); | |
1740 | simplified = true; | |
1741 | break; | |
1742 | } | |
1743 | } | |
927734cf XDL |
1744 | } |
1745 | /* Now clean up the chain. */ | |
1746 | if (simplified) | |
1747 | { | |
1748 | for (i = 0; i < n; i++) | |
5e48d8a0 ML |
1749 | { |
1750 | if ((*preds)[i].is_empty ()) | |
1751 | continue; | |
1752 | s_preds.safe_push ((*preds)[i]); | |
1753 | } | |
927734cf XDL |
1754 | preds->release (); |
1755 | (*preds) = s_preds; | |
1756 | s_preds = vNULL; | |
1757 | } | |
34f97b94 | 1758 | |
927734cf | 1759 | return simplified; |
34f97b94 XDL |
1760 | } |
1761 | ||
927734cf XDL |
1762 | /* The helper function implements the rule 2 for the |
1763 | OR predicate PREDS. | |
1764 | ||
1765 | 3) x OR (!x AND y) is equivalent to x OR y. */ | |
34f97b94 XDL |
1766 | |
1767 | static bool | |
927734cf | 1768 | simplify_preds_3 (pred_chain_union *preds) |
34f97b94 | 1769 | { |
927734cf XDL |
1770 | size_t i, j, n; |
1771 | bool simplified = false; | |
34f97b94 | 1772 | |
927734cf XDL |
1773 | /* Now iteratively simplify X OR (!X AND Z ..) |
1774 | into X OR (Z ...). */ | |
34f97b94 | 1775 | |
927734cf XDL |
1776 | n = preds->length (); |
1777 | if (n < 2) | |
1778 | return false; | |
1779 | ||
1780 | for (i = 0; i < n; i++) | |
34f97b94 | 1781 | { |
927734cf XDL |
1782 | pred_info x; |
1783 | pred_chain *a_chain = &(*preds)[i]; | |
1784 | ||
1785 | if (a_chain->length () != 1) | |
5e48d8a0 | 1786 | continue; |
927734cf XDL |
1787 | |
1788 | x = (*a_chain)[0]; | |
1789 | ||
1790 | for (j = 0; j < n; j++) | |
5e48d8a0 ML |
1791 | { |
1792 | pred_chain *b_chain; | |
1793 | pred_info x2; | |
1794 | size_t k; | |
1795 | ||
1796 | if (j == i) | |
1797 | continue; | |
1798 | ||
1799 | b_chain = &(*preds)[j]; | |
1800 | if (b_chain->length () < 2) | |
1801 | continue; | |
1802 | ||
1803 | for (k = 0; k < b_chain->length (); k++) | |
1804 | { | |
1805 | x2 = (*b_chain)[k]; | |
1806 | if (pred_neg_p (x, x2)) | |
1807 | { | |
1808 | b_chain->unordered_remove (k); | |
1809 | simplified = true; | |
1810 | break; | |
1811 | } | |
1812 | } | |
1813 | } | |
34f97b94 | 1814 | } |
927734cf | 1815 | return simplified; |
34f97b94 XDL |
1816 | } |
1817 | ||
927734cf XDL |
1818 | /* The helper function implements the rule 4 for the |
1819 | OR predicate PREDS. | |
1820 | ||
1821 | 2) ((x AND y) != 0) OR (x != 0 AND y != 0) is equivalent to | |
1822 | (x != 0 ANd y != 0). */ | |
34f97b94 XDL |
1823 | |
1824 | static bool | |
927734cf | 1825 | simplify_preds_4 (pred_chain_union *preds) |
34f97b94 | 1826 | { |
927734cf XDL |
1827 | size_t i, j, n; |
1828 | bool simplified = false; | |
1829 | pred_chain_union s_preds = vNULL; | |
355fe088 | 1830 | gimple *def_stmt; |
34f97b94 | 1831 | |
927734cf | 1832 | n = preds->length (); |
34f97b94 XDL |
1833 | for (i = 0; i < n; i++) |
1834 | { | |
927734cf XDL |
1835 | pred_info z; |
1836 | pred_chain *a_chain = &(*preds)[i]; | |
1837 | ||
1838 | if (a_chain->length () != 1) | |
5e48d8a0 | 1839 | continue; |
927734cf XDL |
1840 | |
1841 | z = (*a_chain)[0]; | |
1842 | ||
1843 | if (!is_neq_zero_form_p (z)) | |
5e48d8a0 | 1844 | continue; |
927734cf XDL |
1845 | |
1846 | def_stmt = SSA_NAME_DEF_STMT (z.pred_lhs); | |
1847 | if (gimple_code (def_stmt) != GIMPLE_ASSIGN) | |
5e48d8a0 | 1848 | continue; |
927734cf XDL |
1849 | |
1850 | if (gimple_assign_rhs_code (def_stmt) != BIT_AND_EXPR) | |
5e48d8a0 | 1851 | continue; |
927734cf XDL |
1852 | |
1853 | for (j = 0; j < n; j++) | |
5e48d8a0 ML |
1854 | { |
1855 | pred_chain *b_chain; | |
1856 | pred_info x2, y2; | |
1857 | ||
1858 | if (j == i) | |
1859 | continue; | |
1860 | ||
1861 | b_chain = &(*preds)[j]; | |
1862 | if (b_chain->length () != 2) | |
1863 | continue; | |
1864 | ||
1865 | x2 = (*b_chain)[0]; | |
1866 | y2 = (*b_chain)[1]; | |
ac0e4fde | 1867 | if (!is_neq_zero_form_p (x2) || !is_neq_zero_form_p (y2)) |
5e48d8a0 ML |
1868 | continue; |
1869 | ||
1870 | if ((pred_expr_equal_p (x2, gimple_assign_rhs1 (def_stmt)) | |
1871 | && pred_expr_equal_p (y2, gimple_assign_rhs2 (def_stmt))) | |
1872 | || (pred_expr_equal_p (x2, gimple_assign_rhs2 (def_stmt)) | |
1873 | && pred_expr_equal_p (y2, gimple_assign_rhs1 (def_stmt)))) | |
1874 | { | |
1875 | /* Kill a_chain. */ | |
1876 | a_chain->release (); | |
1877 | simplified = true; | |
1878 | break; | |
1879 | } | |
1880 | } | |
927734cf XDL |
1881 | } |
1882 | /* Now clean up the chain. */ | |
1883 | if (simplified) | |
1884 | { | |
1885 | for (i = 0; i < n; i++) | |
5e48d8a0 ML |
1886 | { |
1887 | if ((*preds)[i].is_empty ()) | |
1888 | continue; | |
1889 | s_preds.safe_push ((*preds)[i]); | |
1890 | } | |
a4f0c29d | 1891 | |
3703d095 | 1892 | preds->release (); |
927734cf XDL |
1893 | (*preds) = s_preds; |
1894 | s_preds = vNULL; | |
34f97b94 XDL |
1895 | } |
1896 | ||
927734cf | 1897 | return simplified; |
34f97b94 XDL |
1898 | } |
1899 | ||
927734cf XDL |
1900 | /* This function simplifies predicates in PREDS. */ |
1901 | ||
1902 | static void | |
355fe088 | 1903 | simplify_preds (pred_chain_union *preds, gimple *use_or_def, bool is_use) |
34f97b94 | 1904 | { |
927734cf XDL |
1905 | size_t i, n; |
1906 | bool changed = false; | |
34f97b94 | 1907 | |
927734cf | 1908 | if (dump_file && dump_flags & TDF_DETAILS) |
34f97b94 | 1909 | { |
927734cf XDL |
1910 | fprintf (dump_file, "[BEFORE SIMPLICATION -- "); |
1911 | dump_predicates (use_or_def, *preds, is_use ? "[USE]:\n" : "[DEF]:\n"); | |
34f97b94 XDL |
1912 | } |
1913 | ||
927734cf XDL |
1914 | for (i = 0; i < preds->length (); i++) |
1915 | simplify_pred (&(*preds)[i]); | |
1916 | ||
1917 | n = preds->length (); | |
1918 | if (n < 2) | |
1919 | return; | |
1920 | ||
1921 | do | |
1922 | { | |
1923 | changed = false; | |
1924 | if (simplify_preds_2 (preds)) | |
5e48d8a0 | 1925 | changed = true; |
927734cf XDL |
1926 | |
1927 | /* Now iteratively simplify X OR (!X AND Z ..) | |
1928 | into X OR (Z ...). */ | |
1929 | if (simplify_preds_3 (preds)) | |
5e48d8a0 | 1930 | changed = true; |
927734cf XDL |
1931 | |
1932 | if (simplify_preds_4 (preds)) | |
5e48d8a0 | 1933 | changed = true; |
ac0e4fde ML |
1934 | } |
1935 | while (changed); | |
927734cf XDL |
1936 | |
1937 | return; | |
34f97b94 XDL |
1938 | } |
1939 | ||
927734cf | 1940 | /* This is a helper function which attempts to normalize predicate chains |
ac0e4fde | 1941 | by following UD chains. It basically builds up a big tree of either IOR |
5e48d8a0 | 1942 | operations or AND operations, and convert the IOR tree into a |
927734cf XDL |
1943 | pred_chain_union or BIT_AND tree into a pred_chain. |
1944 | Example: | |
56b67510 | 1945 | |
927734cf XDL |
1946 | _3 = _2 RELOP1 _1; |
1947 | _6 = _5 RELOP2 _4; | |
1948 | _9 = _8 RELOP3 _7; | |
1949 | _10 = _3 | _6; | |
1950 | _12 = _9 | _0; | |
1951 | _t = _10 | _12; | |
1952 | ||
1953 | then _t != 0 will be normalized into a pred_chain_union | |
1954 | ||
1955 | (_2 RELOP1 _1) OR (_5 RELOP2 _4) OR (_8 RELOP3 _7) OR (_0 != 0) | |
1956 | ||
1957 | Similarly given, | |
1958 | ||
1959 | _3 = _2 RELOP1 _1; | |
1960 | _6 = _5 RELOP2 _4; | |
1961 | _9 = _8 RELOP3 _7; | |
1962 | _10 = _3 & _6; | |
1963 | _12 = _9 & _0; | |
1964 | ||
1965 | then _t != 0 will be normalized into a pred_chain: | |
1966 | (_2 RELOP1 _1) AND (_5 RELOP2 _4) AND (_8 RELOP3 _7) AND (_0 != 0) | |
5e48d8a0 | 1967 | |
927734cf XDL |
1968 | */ |
1969 | ||
1970 | /* This is a helper function that stores a PRED into NORM_PREDS. */ | |
1971 | ||
1972 | inline static void | |
1973 | push_pred (pred_chain_union *norm_preds, pred_info pred) | |
56b67510 | 1974 | { |
927734cf XDL |
1975 | pred_chain pred_chain = vNULL; |
1976 | pred_chain.safe_push (pred); | |
1977 | norm_preds->safe_push (pred_chain); | |
1978 | } | |
56b67510 | 1979 | |
927734cf XDL |
1980 | /* A helper function that creates a predicate of the form |
1981 | OP != 0 and push it WORK_LIST. */ | |
56b67510 | 1982 | |
927734cf | 1983 | inline static void |
ade3ff24 | 1984 | push_to_worklist (tree op, vec<pred_info, va_heap, vl_ptr> *work_list, |
5e48d8a0 | 1985 | hash_set<tree> *mark_set) |
927734cf | 1986 | { |
6e2830c3 | 1987 | if (mark_set->contains (op)) |
ade3ff24 | 1988 | return; |
6e2830c3 | 1989 | mark_set->add (op); |
ade3ff24 | 1990 | |
927734cf XDL |
1991 | pred_info arg_pred; |
1992 | arg_pred.pred_lhs = op; | |
1993 | arg_pred.pred_rhs = integer_zero_node; | |
1994 | arg_pred.cond_code = NE_EXPR; | |
1995 | arg_pred.invert = false; | |
1996 | work_list->safe_push (arg_pred); | |
1997 | } | |
56b67510 | 1998 | |
927734cf XDL |
1999 | /* A helper that generates a pred_info from a gimple assignment |
2000 | CMP_ASSIGN with comparison rhs. */ | |
56b67510 | 2001 | |
927734cf | 2002 | static pred_info |
355fe088 | 2003 | get_pred_info_from_cmp (gimple *cmp_assign) |
927734cf XDL |
2004 | { |
2005 | pred_info n_pred; | |
2006 | n_pred.pred_lhs = gimple_assign_rhs1 (cmp_assign); | |
2007 | n_pred.pred_rhs = gimple_assign_rhs2 (cmp_assign); | |
2008 | n_pred.cond_code = gimple_assign_rhs_code (cmp_assign); | |
2009 | n_pred.invert = false; | |
2010 | return n_pred; | |
56b67510 XDL |
2011 | } |
2012 | ||
927734cf | 2013 | /* Returns true if the PHI is a degenerated phi with |
ac0e4fde | 2014 | all args with the same value (relop). In that case, *PRED |
927734cf | 2015 | will be updated to that value. */ |
56b67510 XDL |
2016 | |
2017 | static bool | |
355fe088 | 2018 | is_degenerated_phi (gimple *phi, pred_info *pred_p) |
56b67510 | 2019 | { |
927734cf XDL |
2020 | int i, n; |
2021 | tree op0; | |
355fe088 | 2022 | gimple *def0; |
927734cf | 2023 | pred_info pred0; |
56b67510 | 2024 | |
927734cf XDL |
2025 | n = gimple_phi_num_args (phi); |
2026 | op0 = gimple_phi_arg_def (phi, 0); | |
2027 | ||
2028 | if (TREE_CODE (op0) != SSA_NAME) | |
56b67510 XDL |
2029 | return false; |
2030 | ||
927734cf XDL |
2031 | def0 = SSA_NAME_DEF_STMT (op0); |
2032 | if (gimple_code (def0) != GIMPLE_ASSIGN) | |
2033 | return false; | |
ac0e4fde | 2034 | if (TREE_CODE_CLASS (gimple_assign_rhs_code (def0)) != tcc_comparison) |
927734cf XDL |
2035 | return false; |
2036 | pred0 = get_pred_info_from_cmp (def0); | |
2037 | ||
2038 | for (i = 1; i < n; ++i) | |
56b67510 | 2039 | { |
355fe088 | 2040 | gimple *def; |
927734cf XDL |
2041 | pred_info pred; |
2042 | tree op = gimple_phi_arg_def (phi, i); | |
2043 | ||
2044 | if (TREE_CODE (op) != SSA_NAME) | |
5e48d8a0 | 2045 | return false; |
56b67510 | 2046 | |
927734cf XDL |
2047 | def = SSA_NAME_DEF_STMT (op); |
2048 | if (gimple_code (def) != GIMPLE_ASSIGN) | |
5e48d8a0 | 2049 | return false; |
ac0e4fde | 2050 | if (TREE_CODE_CLASS (gimple_assign_rhs_code (def)) != tcc_comparison) |
5e48d8a0 | 2051 | return false; |
927734cf XDL |
2052 | pred = get_pred_info_from_cmp (def); |
2053 | if (!pred_equal_p (pred, pred0)) | |
5e48d8a0 | 2054 | return false; |
927734cf XDL |
2055 | } |
2056 | ||
2057 | *pred_p = pred0; | |
2058 | return true; | |
2059 | } | |
2060 | ||
5e48d8a0 | 2061 | /* Normalize one predicate PRED |
927734cf XDL |
2062 | 1) if PRED can no longer be normlized, put it into NORM_PREDS. |
2063 | 2) otherwise if PRED is of the form x != 0, follow x's definition | |
2064 | and put normalized predicates into WORK_LIST. */ | |
5e48d8a0 | 2065 | |
927734cf | 2066 | static void |
5e48d8a0 ML |
2067 | normalize_one_pred_1 (pred_chain_union *norm_preds, |
2068 | pred_chain *norm_chain, | |
2069 | pred_info pred, | |
2070 | enum tree_code and_or_code, | |
2071 | vec<pred_info, va_heap, vl_ptr> *work_list, | |
6e2830c3 | 2072 | hash_set<tree> *mark_set) |
927734cf XDL |
2073 | { |
2074 | if (!is_neq_zero_form_p (pred)) | |
2075 | { | |
2076 | if (and_or_code == BIT_IOR_EXPR) | |
5e48d8a0 | 2077 | push_pred (norm_preds, pred); |
927734cf | 2078 | else |
5e48d8a0 | 2079 | norm_chain->safe_push (pred); |
927734cf XDL |
2080 | return; |
2081 | } | |
2082 | ||
355fe088 | 2083 | gimple *def_stmt = SSA_NAME_DEF_STMT (pred.pred_lhs); |
5e48d8a0 | 2084 | |
927734cf XDL |
2085 | if (gimple_code (def_stmt) == GIMPLE_PHI |
2086 | && is_degenerated_phi (def_stmt, &pred)) | |
2087 | work_list->safe_push (pred); | |
ac0e4fde | 2088 | else if (gimple_code (def_stmt) == GIMPLE_PHI && and_or_code == BIT_IOR_EXPR) |
927734cf XDL |
2089 | { |
2090 | int i, n; | |
2091 | n = gimple_phi_num_args (def_stmt); | |
2092 | ||
ac0e4fde | 2093 | /* If we see non zero constant, we should punt. The predicate |
927734cf XDL |
2094 | * should be one guarding the phi edge. */ |
2095 | for (i = 0; i < n; ++i) | |
5e48d8a0 ML |
2096 | { |
2097 | tree op = gimple_phi_arg_def (def_stmt, i); | |
2098 | if (TREE_CODE (op) == INTEGER_CST && !integer_zerop (op)) | |
2099 | { | |
2100 | push_pred (norm_preds, pred); | |
2101 | return; | |
2102 | } | |
2103 | } | |
56b67510 | 2104 | |
927734cf | 2105 | for (i = 0; i < n; ++i) |
5e48d8a0 ML |
2106 | { |
2107 | tree op = gimple_phi_arg_def (def_stmt, i); | |
2108 | if (integer_zerop (op)) | |
2109 | continue; | |
927734cf | 2110 | |
5e48d8a0 ML |
2111 | push_to_worklist (op, work_list, mark_set); |
2112 | } | |
ade3ff24 RH |
2113 | } |
2114 | else if (gimple_code (def_stmt) != GIMPLE_ASSIGN) | |
2115 | { | |
2116 | if (and_or_code == BIT_IOR_EXPR) | |
2117 | push_pred (norm_preds, pred); | |
2118 | else | |
2119 | norm_chain->safe_push (pred); | |
2120 | } | |
2121 | else if (gimple_assign_rhs_code (def_stmt) == and_or_code) | |
2122 | { | |
666e8e06 RB |
2123 | /* Avoid splitting up bit manipulations like x & 3 or y | 1. */ |
2124 | if (is_gimple_min_invariant (gimple_assign_rhs2 (def_stmt))) | |
2125 | { | |
2126 | /* But treat x & 3 as condition. */ | |
2127 | if (and_or_code == BIT_AND_EXPR) | |
2128 | { | |
2129 | pred_info n_pred; | |
2130 | n_pred.pred_lhs = gimple_assign_rhs1 (def_stmt); | |
2131 | n_pred.pred_rhs = gimple_assign_rhs2 (def_stmt); | |
2132 | n_pred.cond_code = and_or_code; | |
2133 | n_pred.invert = false; | |
2134 | norm_chain->safe_push (n_pred); | |
2135 | } | |
2136 | } | |
2137 | else | |
2138 | { | |
2139 | push_to_worklist (gimple_assign_rhs1 (def_stmt), work_list, mark_set); | |
2140 | push_to_worklist (gimple_assign_rhs2 (def_stmt), work_list, mark_set); | |
2141 | } | |
ade3ff24 RH |
2142 | } |
2143 | else if (TREE_CODE_CLASS (gimple_assign_rhs_code (def_stmt)) | |
2144 | == tcc_comparison) | |
2145 | { | |
2146 | pred_info n_pred = get_pred_info_from_cmp (def_stmt); | |
2147 | if (and_or_code == BIT_IOR_EXPR) | |
2148 | push_pred (norm_preds, n_pred); | |
2149 | else | |
2150 | norm_chain->safe_push (n_pred); | |
2151 | } | |
2152 | else | |
2153 | { | |
2154 | if (and_or_code == BIT_IOR_EXPR) | |
2155 | push_pred (norm_preds, pred); | |
2156 | else | |
2157 | norm_chain->safe_push (pred); | |
2158 | } | |
927734cf XDL |
2159 | } |
2160 | ||
2161 | /* Normalize PRED and store the normalized predicates into NORM_PREDS. */ | |
2162 | ||
2163 | static void | |
ac0e4fde | 2164 | normalize_one_pred (pred_chain_union *norm_preds, pred_info pred) |
927734cf XDL |
2165 | { |
2166 | vec<pred_info, va_heap, vl_ptr> work_list = vNULL; | |
2167 | enum tree_code and_or_code = ERROR_MARK; | |
2168 | pred_chain norm_chain = vNULL; | |
56b67510 | 2169 | |
927734cf | 2170 | if (!is_neq_zero_form_p (pred)) |
56b67510 | 2171 | { |
927734cf XDL |
2172 | push_pred (norm_preds, pred); |
2173 | return; | |
2174 | } | |
56b67510 | 2175 | |
355fe088 | 2176 | gimple *def_stmt = SSA_NAME_DEF_STMT (pred.pred_lhs); |
927734cf XDL |
2177 | if (gimple_code (def_stmt) == GIMPLE_ASSIGN) |
2178 | and_or_code = gimple_assign_rhs_code (def_stmt); | |
ac0e4fde | 2179 | if (and_or_code != BIT_IOR_EXPR && and_or_code != BIT_AND_EXPR) |
927734cf | 2180 | { |
ac0e4fde | 2181 | if (TREE_CODE_CLASS (and_or_code) == tcc_comparison) |
5e48d8a0 ML |
2182 | { |
2183 | pred_info n_pred = get_pred_info_from_cmp (def_stmt); | |
2184 | push_pred (norm_preds, n_pred); | |
2185 | } | |
ac0e4fde ML |
2186 | else |
2187 | push_pred (norm_preds, pred); | |
927734cf XDL |
2188 | return; |
2189 | } | |
56b67510 | 2190 | |
927734cf | 2191 | work_list.safe_push (pred); |
6e2830c3 | 2192 | hash_set<tree> mark_set; |
ade3ff24 | 2193 | |
927734cf XDL |
2194 | while (!work_list.is_empty ()) |
2195 | { | |
2196 | pred_info a_pred = work_list.pop (); | |
ac0e4fde ML |
2197 | normalize_one_pred_1 (norm_preds, &norm_chain, a_pred, and_or_code, |
2198 | &work_list, &mark_set); | |
56b67510 | 2199 | } |
927734cf XDL |
2200 | if (and_or_code == BIT_AND_EXPR) |
2201 | norm_preds->safe_push (norm_chain); | |
2202 | ||
2203 | work_list.release (); | |
2204 | } | |
56b67510 | 2205 | |
927734cf | 2206 | static void |
ac0e4fde | 2207 | normalize_one_pred_chain (pred_chain_union *norm_preds, pred_chain one_chain) |
927734cf XDL |
2208 | { |
2209 | vec<pred_info, va_heap, vl_ptr> work_list = vNULL; | |
6e2830c3 | 2210 | hash_set<tree> mark_set; |
927734cf XDL |
2211 | pred_chain norm_chain = vNULL; |
2212 | size_t i; | |
2213 | ||
2214 | for (i = 0; i < one_chain.length (); i++) | |
ade3ff24 RH |
2215 | { |
2216 | work_list.safe_push (one_chain[i]); | |
6e2830c3 | 2217 | mark_set.add (one_chain[i].pred_lhs); |
ade3ff24 | 2218 | } |
927734cf XDL |
2219 | |
2220 | while (!work_list.is_empty ()) | |
56b67510 | 2221 | { |
927734cf | 2222 | pred_info a_pred = work_list.pop (); |
ac0e4fde ML |
2223 | normalize_one_pred_1 (0, &norm_chain, a_pred, BIT_AND_EXPR, &work_list, |
2224 | &mark_set); | |
56b67510 | 2225 | } |
927734cf XDL |
2226 | |
2227 | norm_preds->safe_push (norm_chain); | |
2228 | work_list.release (); | |
56b67510 XDL |
2229 | } |
2230 | ||
927734cf XDL |
2231 | /* Normalize predicate chains PREDS and returns the normalized one. */ |
2232 | ||
2233 | static pred_chain_union | |
355fe088 | 2234 | normalize_preds (pred_chain_union preds, gimple *use_or_def, bool is_use) |
927734cf XDL |
2235 | { |
2236 | pred_chain_union norm_preds = vNULL; | |
2237 | size_t n = preds.length (); | |
2238 | size_t i; | |
2239 | ||
2240 | if (dump_file && dump_flags & TDF_DETAILS) | |
2241 | { | |
2242 | fprintf (dump_file, "[BEFORE NORMALIZATION --"); | |
2243 | dump_predicates (use_or_def, preds, is_use ? "[USE]:\n" : "[DEF]:\n"); | |
2244 | } | |
2245 | ||
2246 | for (i = 0; i < n; i++) | |
2247 | { | |
2248 | if (preds[i].length () != 1) | |
5e48d8a0 | 2249 | normalize_one_pred_chain (&norm_preds, preds[i]); |
927734cf | 2250 | else |
5e48d8a0 ML |
2251 | { |
2252 | normalize_one_pred (&norm_preds, preds[i][0]); | |
2253 | preds[i].release (); | |
2254 | } | |
927734cf XDL |
2255 | } |
2256 | ||
2257 | if (dump_file) | |
2258 | { | |
2259 | fprintf (dump_file, "[AFTER NORMALIZATION -- "); | |
ac0e4fde ML |
2260 | dump_predicates (use_or_def, norm_preds, |
2261 | is_use ? "[USE]:\n" : "[DEF]:\n"); | |
927734cf XDL |
2262 | } |
2263 | ||
a4f0c29d | 2264 | destroy_predicate_vecs (&preds); |
927734cf XDL |
2265 | return norm_preds; |
2266 | } | |
56b67510 | 2267 | |
358a95e4 | 2268 | /* Return TRUE if PREDICATE can be invalidated by any individual |
11ef0b22 | 2269 | predicate in USE_GUARD. */ |
358a95e4 AH |
2270 | |
2271 | static bool | |
2272 | can_one_predicate_be_invalidated_p (pred_info predicate, | |
95ac78ce | 2273 | pred_chain use_guard) |
358a95e4 | 2274 | { |
11ef0b22 AH |
2275 | if (dump_file && dump_flags & TDF_DETAILS) |
2276 | { | |
2277 | fprintf (dump_file, "Testing if this predicate: "); | |
2278 | dump_pred_info (predicate); | |
2279 | fprintf (dump_file, "\n...can be invalidated by a USE guard of: "); | |
2280 | dump_pred_chain (use_guard); | |
2281 | } | |
95ac78ce | 2282 | for (size_t i = 0; i < use_guard.length (); ++i) |
358a95e4 | 2283 | { |
358a95e4 AH |
2284 | /* NOTE: This is a very simple check, and only understands an |
2285 | exact opposite. So, [i == 0] is currently only invalidated | |
2286 | by [.NOT. i == 0] or [i != 0]. Ideally we should also | |
2287 | invalidate with say [i > 5] or [i == 8]. There is certainly | |
2288 | room for improvement here. */ | |
95ac78ce | 2289 | if (pred_neg_p (predicate, use_guard[i])) |
11ef0b22 AH |
2290 | { |
2291 | if (dump_file && dump_flags & TDF_DETAILS) | |
2292 | { | |
2293 | fprintf (dump_file, " Predicate was invalidated by: "); | |
2294 | dump_pred_info (use_guard[i]); | |
2295 | fputc ('\n', dump_file); | |
2296 | } | |
2297 | return true; | |
2298 | } | |
358a95e4 AH |
2299 | } |
2300 | return false; | |
2301 | } | |
2302 | ||
95ac78ce AH |
2303 | /* Return TRUE if all predicates in UNINIT_PRED are invalidated by |
2304 | USE_GUARD being true. */ | |
358a95e4 AH |
2305 | |
2306 | static bool | |
95ac78ce AH |
2307 | can_chain_union_be_invalidated_p (pred_chain_union uninit_pred, |
2308 | pred_chain use_guard) | |
358a95e4 | 2309 | { |
95ac78ce AH |
2310 | if (uninit_pred.is_empty ()) |
2311 | return false; | |
11ef0b22 AH |
2312 | if (dump_file && dump_flags & TDF_DETAILS) |
2313 | dump_predicates (NULL, uninit_pred, | |
2314 | "Testing if anything here can be invalidated: "); | |
95ac78ce | 2315 | for (size_t i = 0; i < uninit_pred.length (); ++i) |
358a95e4 | 2316 | { |
95ac78ce | 2317 | pred_chain c = uninit_pred[i]; |
11ef0b22 AH |
2318 | size_t j; |
2319 | for (j = 0; j < c.length (); ++j) | |
2320 | if (can_one_predicate_be_invalidated_p (c[j], use_guard)) | |
2321 | break; | |
2322 | ||
2323 | /* If we were unable to invalidate any predicate in C, then there | |
2324 | is a viable path from entry to the PHI where the PHI takes | |
2325 | an uninitialized value and continues to a use of the PHI. */ | |
2326 | if (j == c.length ()) | |
2327 | return false; | |
358a95e4 AH |
2328 | } |
2329 | return true; | |
2330 | } | |
2331 | ||
95ac78ce AH |
2332 | /* Return TRUE if none of the uninitialized operands in UNINT_OPNDS |
2333 | can actually happen if we arrived at a use for PHI. | |
358a95e4 | 2334 | |
95ac78ce | 2335 | PHI_USE_GUARDS are the guard conditions for the use of the PHI. */ |
358a95e4 | 2336 | |
95ac78ce AH |
2337 | static bool |
2338 | uninit_uses_cannot_happen (gphi *phi, unsigned uninit_opnds, | |
2339 | pred_chain_union phi_use_guards) | |
358a95e4 | 2340 | { |
95ac78ce AH |
2341 | unsigned phi_args = gimple_phi_num_args (phi); |
2342 | if (phi_args > max_phi_args) | |
2343 | return false; | |
358a95e4 | 2344 | |
95ac78ce AH |
2345 | /* PHI_USE_GUARDS are OR'ed together. If we have more than one |
2346 | possible guard, there's no way of knowing which guard was true. | |
2347 | Since we need to be absolutely sure that the uninitialized | |
2348 | operands will be invalidated, bail. */ | |
2349 | if (phi_use_guards.length () != 1) | |
2350 | return false; | |
358a95e4 | 2351 | |
358a95e4 | 2352 | /* Look for the control dependencies of all the uninitialized |
95ac78ce | 2353 | operands and build guard predicates describing them. */ |
3703d095 AH |
2354 | pred_chain_union uninit_preds; |
2355 | bool ret = true; | |
2356 | for (unsigned i = 0; i < phi_args; ++i) | |
358a95e4 AH |
2357 | { |
2358 | if (!MASK_TEST_BIT (uninit_opnds, i)) | |
2359 | continue; | |
2360 | ||
2361 | edge e = gimple_phi_arg_edge (phi, i); | |
2362 | vec<edge> dep_chains[MAX_NUM_CHAINS]; | |
2363 | auto_vec<edge, MAX_CHAIN_LEN + 1> cur_chain; | |
2364 | size_t num_chains = 0; | |
2365 | int num_calls = 0; | |
2366 | ||
95ac78ce | 2367 | /* Build the control dependency chain for uninit operand `i'... */ |
3703d095 | 2368 | uninit_preds = vNULL; |
11ef0b22 | 2369 | if (!compute_control_dep_chain (ENTRY_BLOCK_PTR_FOR_FN (cfun), |
95ac78ce AH |
2370 | e->src, dep_chains, &num_chains, |
2371 | &cur_chain, &num_calls)) | |
3703d095 AH |
2372 | { |
2373 | ret = false; | |
2374 | break; | |
2375 | } | |
95ac78ce | 2376 | /* ...and convert it into a set of predicates. */ |
11ef0b22 AH |
2377 | bool has_valid_preds |
2378 | = convert_control_dep_chain_into_preds (dep_chains, num_chains, | |
2379 | &uninit_preds); | |
95ac78ce AH |
2380 | for (size_t j = 0; j < num_chains; ++j) |
2381 | dep_chains[j].release (); | |
11ef0b22 AH |
2382 | if (!has_valid_preds) |
2383 | { | |
2384 | ret = false; | |
2385 | break; | |
2386 | } | |
3703d095 AH |
2387 | simplify_preds (&uninit_preds, NULL, false); |
2388 | uninit_preds = normalize_preds (uninit_preds, NULL, false); | |
95ac78ce AH |
2389 | |
2390 | /* Can the guard for this uninitialized operand be invalidated | |
2391 | by the PHI use? */ | |
3703d095 AH |
2392 | if (!can_chain_union_be_invalidated_p (uninit_preds, phi_use_guards[0])) |
2393 | { | |
2394 | ret = false; | |
2395 | break; | |
2396 | } | |
358a95e4 | 2397 | } |
3703d095 AH |
2398 | destroy_predicate_vecs (&uninit_preds); |
2399 | return ret; | |
358a95e4 AH |
2400 | } |
2401 | ||
34f97b94 XDL |
2402 | /* Computes the predicates that guard the use and checks |
2403 | if the incoming paths that have empty (or possibly | |
ac0e4fde | 2404 | empty) definition can be pruned/filtered. The function returns |
34f97b94 XDL |
2405 | true if it can be determined that the use of PHI's def in |
2406 | USE_STMT is guarded with a predicate set not overlapping with | |
2407 | predicate sets of all runtime paths that do not have a definition. | |
c0503346 | 2408 | |
67914693 | 2409 | Returns false if it is not or it cannot be determined. USE_BB is |
34f97b94 | 2410 | the bb of the use (for phi operand use, the bb is not the bb of |
c0503346 PP |
2411 | the phi stmt, but the src bb of the operand edge). |
2412 | ||
ac0e4fde | 2413 | UNINIT_OPNDS is a bit vector. If an operand of PHI is uninitialized, the |
c0503346 PP |
2414 | corresponding bit in the vector is 1. VISITED_PHIS is a pointer |
2415 | set of phis being visited. | |
2416 | ||
2417 | *DEF_PREDS contains the (memoized) defining predicate chains of PHI. | |
2418 | If *DEF_PREDS is the empty vector, the defining predicate chains of | |
2419 | PHI will be computed and stored into *DEF_PREDS as needed. | |
2420 | ||
2421 | VISITED_PHIS is a pointer set of phis being visited. */ | |
34f97b94 XDL |
2422 | |
2423 | static bool | |
355fe088 | 2424 | is_use_properly_guarded (gimple *use_stmt, |
5e48d8a0 ML |
2425 | basic_block use_bb, |
2426 | gphi *phi, | |
2427 | unsigned uninit_opnds, | |
c0503346 | 2428 | pred_chain_union *def_preds, |
5e48d8a0 | 2429 | hash_set<gphi *> *visited_phis) |
34f97b94 XDL |
2430 | { |
2431 | basic_block phi_bb; | |
927734cf | 2432 | pred_chain_union preds = vNULL; |
34f97b94 XDL |
2433 | bool has_valid_preds = false; |
2434 | bool is_properly_guarded = false; | |
2435 | ||
6e2830c3 | 2436 | if (visited_phis->add (phi)) |
34f97b94 XDL |
2437 | return false; |
2438 | ||
2439 | phi_bb = gimple_bb (phi); | |
2440 | ||
2441 | if (is_non_loop_exit_postdominating (use_bb, phi_bb)) | |
2442 | return false; | |
2443 | ||
927734cf | 2444 | has_valid_preds = find_predicates (&preds, phi_bb, use_bb); |
34f97b94 XDL |
2445 | |
2446 | if (!has_valid_preds) | |
2447 | { | |
a4f0c29d | 2448 | destroy_predicate_vecs (&preds); |
34f97b94 XDL |
2449 | return false; |
2450 | } | |
2451 | ||
ac0e4fde | 2452 | /* Try to prune the dead incoming phi edges. */ |
927734cf XDL |
2453 | is_properly_guarded |
2454 | = use_pred_not_overlap_with_undef_path_pred (preds, phi, uninit_opnds, | |
2455 | visited_phis); | |
34f97b94 | 2456 | |
358a95e4 AH |
2457 | /* We might be able to prove that if the control dependencies |
2458 | for UNINIT_OPNDS are true, that the control dependencies for | |
2459 | USE_STMT can never be true. */ | |
2460 | if (!is_properly_guarded) | |
95ac78ce AH |
2461 | is_properly_guarded |= uninit_uses_cannot_happen (phi, uninit_opnds, |
2462 | preds); | |
358a95e4 | 2463 | |
927734cf | 2464 | if (is_properly_guarded) |
34f97b94 | 2465 | { |
a4f0c29d | 2466 | destroy_predicate_vecs (&preds); |
927734cf XDL |
2467 | return true; |
2468 | } | |
56b67510 | 2469 | |
c0503346 | 2470 | if (def_preds->is_empty ()) |
927734cf | 2471 | { |
c0503346 PP |
2472 | has_valid_preds = find_def_preds (def_preds, phi); |
2473 | ||
2474 | if (!has_valid_preds) | |
2475 | { | |
a4f0c29d | 2476 | destroy_predicate_vecs (&preds); |
c0503346 PP |
2477 | return false; |
2478 | } | |
2479 | ||
2480 | simplify_preds (def_preds, phi, false); | |
2481 | *def_preds = normalize_preds (*def_preds, phi, false); | |
34f97b94 XDL |
2482 | } |
2483 | ||
927734cf XDL |
2484 | simplify_preds (&preds, use_stmt, true); |
2485 | preds = normalize_preds (preds, use_stmt, true); | |
2486 | ||
c0503346 | 2487 | is_properly_guarded = is_superset_of (*def_preds, preds); |
34f97b94 | 2488 | |
a4f0c29d | 2489 | destroy_predicate_vecs (&preds); |
34f97b94 XDL |
2490 | return is_properly_guarded; |
2491 | } | |
2492 | ||
2493 | /* Searches through all uses of a potentially | |
2494 | uninitialized variable defined by PHI and returns a use | |
ac0e4fde ML |
2495 | statement if the use is not properly guarded. It returns |
2496 | NULL if all uses are guarded. UNINIT_OPNDS is a bitvector | |
2497 | holding the position(s) of uninit PHI operands. WORKLIST | |
34f97b94 | 2498 | is the vector of candidate phis that may be updated by this |
ac0e4fde | 2499 | function. ADDED_TO_WORKLIST is the pointer set tracking |
34f97b94 XDL |
2500 | if the new phi is already in the worklist. */ |
2501 | ||
355fe088 | 2502 | static gimple * |
538dd0b7 | 2503 | find_uninit_use (gphi *phi, unsigned uninit_opnds, |
5e48d8a0 | 2504 | vec<gphi *> *worklist, |
538dd0b7 | 2505 | hash_set<gphi *> *added_to_worklist) |
34f97b94 XDL |
2506 | { |
2507 | tree phi_result; | |
2508 | use_operand_p use_p; | |
355fe088 | 2509 | gimple *use_stmt; |
34f97b94 | 2510 | imm_use_iterator iter; |
c0503346 | 2511 | pred_chain_union def_preds = vNULL; |
355fe088 | 2512 | gimple *ret = NULL; |
34f97b94 XDL |
2513 | |
2514 | phi_result = gimple_phi_result (phi); | |
2515 | ||
2516 | FOR_EACH_IMM_USE_FAST (use_p, iter, phi_result) | |
2517 | { | |
34f97b94 XDL |
2518 | basic_block use_bb; |
2519 | ||
480161b5 RG |
2520 | use_stmt = USE_STMT (use_p); |
2521 | if (is_gimple_debug (use_stmt)) | |
2522 | continue; | |
34f97b94 | 2523 | |
ac0e4fde | 2524 | if (gphi *use_phi = dyn_cast<gphi *> (use_stmt)) |
538dd0b7 | 2525 | use_bb = gimple_phi_arg_edge (use_phi, |
480161b5 RG |
2526 | PHI_ARG_INDEX_FROM_USE (use_p))->src; |
2527 | else | |
2528 | use_bb = gimple_bb (use_stmt); | |
34f97b94 | 2529 | |
538dd0b7 | 2530 | hash_set<gphi *> visited_phis; |
927734cf | 2531 | if (is_use_properly_guarded (use_stmt, use_bb, phi, uninit_opnds, |
c0503346 | 2532 | &def_preds, &visited_phis)) |
6e2830c3 | 2533 | continue; |
34f97b94 | 2534 | |
e74780a3 | 2535 | if (dump_file && (dump_flags & TDF_DETAILS)) |
5e48d8a0 ML |
2536 | { |
2537 | fprintf (dump_file, "[CHECK]: Found unguarded use: "); | |
ef6cb4c7 | 2538 | print_gimple_stmt (dump_file, use_stmt, 0); |
5e48d8a0 | 2539 | } |
34f97b94 XDL |
2540 | /* Found one real use, return. */ |
2541 | if (gimple_code (use_stmt) != GIMPLE_PHI) | |
c0503346 PP |
2542 | { |
2543 | ret = use_stmt; | |
2544 | break; | |
2545 | } | |
34f97b94 XDL |
2546 | |
2547 | /* Found a phi use that is not guarded, | |
5e48d8a0 | 2548 | add the phi to the worklist. */ |
ac0e4fde | 2549 | if (!added_to_worklist->add (as_a<gphi *> (use_stmt))) |
5e48d8a0 ML |
2550 | { |
2551 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2552 | { | |
2553 | fprintf (dump_file, "[WORKLIST]: Update worklist with phi: "); | |
ef6cb4c7 | 2554 | print_gimple_stmt (dump_file, use_stmt, 0); |
5e48d8a0 ML |
2555 | } |
2556 | ||
ac0e4fde | 2557 | worklist->safe_push (as_a<gphi *> (use_stmt)); |
5e48d8a0 ML |
2558 | possibly_undefined_names->add (phi_result); |
2559 | } | |
34f97b94 XDL |
2560 | } |
2561 | ||
a4f0c29d | 2562 | destroy_predicate_vecs (&def_preds); |
c0503346 | 2563 | return ret; |
34f97b94 XDL |
2564 | } |
2565 | ||
2566 | /* Look for inputs to PHI that are SSA_NAMEs that have empty definitions | |
2567 | and gives warning if there exists a runtime path from the entry to a | |
ac0e4fde ML |
2568 | use of the PHI def that does not contain a definition. In other words, |
2569 | the warning is on the real use. The more dead paths that can be pruned | |
2570 | by the compiler, the fewer false positives the warning is. WORKLIST | |
2571 | is a vector of candidate phis to be examined. ADDED_TO_WORKLIST is | |
34f97b94 XDL |
2572 | a pointer set tracking if the new phi is added to the worklist or not. */ |
2573 | ||
2574 | static void | |
538dd0b7 | 2575 | warn_uninitialized_phi (gphi *phi, vec<gphi *> *worklist, |
5e48d8a0 | 2576 | hash_set<gphi *> *added_to_worklist) |
34f97b94 XDL |
2577 | { |
2578 | unsigned uninit_opnds; | |
355fe088 | 2579 | gimple *uninit_use_stmt = 0; |
34f97b94 | 2580 | tree uninit_op; |
e1ec47c4 TP |
2581 | int phiarg_index; |
2582 | location_t loc; | |
34f97b94 | 2583 | |
ea057359 RG |
2584 | /* Don't look at virtual operands. */ |
2585 | if (virtual_operand_p (gimple_phi_result (phi))) | |
34f97b94 XDL |
2586 | return; |
2587 | ||
2588 | uninit_opnds = compute_uninit_opnds_pos (phi); | |
2589 | ||
ac0e4fde | 2590 | if (MASK_EMPTY (uninit_opnds)) |
34f97b94 XDL |
2591 | return; |
2592 | ||
e74780a3 XDL |
2593 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2594 | { | |
2595 | fprintf (dump_file, "[CHECK]: examining phi: "); | |
ef6cb4c7 | 2596 | print_gimple_stmt (dump_file, phi, 0); |
e74780a3 XDL |
2597 | } |
2598 | ||
34f97b94 XDL |
2599 | /* Now check if we have any use of the value without proper guard. */ |
2600 | uninit_use_stmt = find_uninit_use (phi, uninit_opnds, | |
5e48d8a0 | 2601 | worklist, added_to_worklist); |
34f97b94 XDL |
2602 | |
2603 | /* All uses are properly guarded. */ | |
2604 | if (!uninit_use_stmt) | |
2605 | return; | |
2606 | ||
e1ec47c4 TP |
2607 | phiarg_index = MASK_FIRST_SET_BIT (uninit_opnds); |
2608 | uninit_op = gimple_phi_arg_def (phi, phiarg_index); | |
70b5e7dc RG |
2609 | if (SSA_NAME_VAR (uninit_op) == NULL_TREE) |
2610 | return; | |
e1ec47c4 TP |
2611 | if (gimple_phi_arg_has_location (phi, phiarg_index)) |
2612 | loc = gimple_phi_arg_location (phi, phiarg_index); | |
2613 | else | |
2614 | loc = UNKNOWN_LOCATION; | |
8d2b0410 RG |
2615 | warn_uninit (OPT_Wmaybe_uninitialized, uninit_op, SSA_NAME_VAR (uninit_op), |
2616 | SSA_NAME_VAR (uninit_op), | |
5e48d8a0 ML |
2617 | "%qD may be used uninitialized in this function", |
2618 | uninit_use_stmt, loc); | |
34f97b94 XDL |
2619 | } |
2620 | ||
be55bfe6 TS |
2621 | static bool |
2622 | gate_warn_uninitialized (void) | |
2623 | { | |
2624 | return warn_uninitialized || warn_maybe_uninitialized; | |
2625 | } | |
34f97b94 | 2626 | |
be55bfe6 | 2627 | namespace { |
34f97b94 | 2628 | |
be55bfe6 TS |
2629 | const pass_data pass_data_late_warn_uninitialized = |
2630 | { | |
2631 | GIMPLE_PASS, /* type */ | |
2632 | "uninit", /* name */ | |
2633 | OPTGROUP_NONE, /* optinfo_flags */ | |
be55bfe6 TS |
2634 | TV_NONE, /* tv_id */ |
2635 | PROP_ssa, /* properties_required */ | |
2636 | 0, /* properties_provided */ | |
2637 | 0, /* properties_destroyed */ | |
2638 | 0, /* todo_flags_start */ | |
2639 | 0, /* todo_flags_finish */ | |
2640 | }; | |
2641 | ||
2642 | class pass_late_warn_uninitialized : public gimple_opt_pass | |
2643 | { | |
2644 | public: | |
2645 | pass_late_warn_uninitialized (gcc::context *ctxt) | |
2646 | : gimple_opt_pass (pass_data_late_warn_uninitialized, ctxt) | |
2647 | {} | |
2648 | ||
2649 | /* opt_pass methods: */ | |
ac0e4fde | 2650 | opt_pass *clone () { return new pass_late_warn_uninitialized (m_ctxt); } |
be55bfe6 TS |
2651 | virtual bool gate (function *) { return gate_warn_uninitialized (); } |
2652 | virtual unsigned int execute (function *); | |
2653 | ||
2654 | }; // class pass_late_warn_uninitialized | |
2655 | ||
2656 | unsigned int | |
2657 | pass_late_warn_uninitialized::execute (function *fun) | |
34f97b94 XDL |
2658 | { |
2659 | basic_block bb; | |
538dd0b7 DM |
2660 | gphi_iterator gsi; |
2661 | vec<gphi *> worklist = vNULL; | |
34f97b94 XDL |
2662 | |
2663 | calculate_dominance_info (CDI_DOMINATORS); | |
2664 | calculate_dominance_info (CDI_POST_DOMINATORS); | |
2665 | /* Re-do the plain uninitialized variable check, as optimization may have | |
2666 | straightened control flow. Do this first so that we don't accidentally | |
2667 | get a "may be" warning when we'd have seen an "is" warning later. */ | |
2668 | warn_uninitialized_vars (/*warn_possibly_uninitialized=*/1); | |
2669 | ||
2670 | timevar_push (TV_TREE_UNINIT); | |
2671 | ||
6e2830c3 | 2672 | possibly_undefined_names = new hash_set<tree>; |
538dd0b7 | 2673 | hash_set<gphi *> added_to_worklist; |
34f97b94 XDL |
2674 | |
2675 | /* Initialize worklist */ | |
be55bfe6 | 2676 | FOR_EACH_BB_FN (bb, fun) |
34f97b94 XDL |
2677 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
2678 | { | |
538dd0b7 | 2679 | gphi *phi = gsi.phi (); |
be55bfe6 TS |
2680 | size_t n, i; |
2681 | ||
2682 | n = gimple_phi_num_args (phi); | |
2683 | ||
2684 | /* Don't look at virtual operands. */ | |
2685 | if (virtual_operand_p (gimple_phi_result (phi))) | |
2686 | continue; | |
2687 | ||
2688 | for (i = 0; i < n; ++i) | |
2689 | { | |
2690 | tree op = gimple_phi_arg_def (phi, i); | |
ac0e4fde | 2691 | if (TREE_CODE (op) == SSA_NAME && uninit_undefined_value_p (op)) |
be55bfe6 TS |
2692 | { |
2693 | worklist.safe_push (phi); | |
6e2830c3 | 2694 | added_to_worklist.add (phi); |
be55bfe6 TS |
2695 | if (dump_file && (dump_flags & TDF_DETAILS)) |
2696 | { | |
2697 | fprintf (dump_file, "[WORKLIST]: add to initial list: "); | |
ef6cb4c7 | 2698 | print_gimple_stmt (dump_file, phi, 0); |
be55bfe6 TS |
2699 | } |
2700 | break; | |
2701 | } | |
2702 | } | |
34f97b94 XDL |
2703 | } |
2704 | ||
9771b263 | 2705 | while (worklist.length () != 0) |
34f97b94 | 2706 | { |
538dd0b7 | 2707 | gphi *cur_phi = 0; |
9771b263 | 2708 | cur_phi = worklist.pop (); |
6e2830c3 | 2709 | warn_uninitialized_phi (cur_phi, &worklist, &added_to_worklist); |
34f97b94 | 2710 | } |
e74780a3 | 2711 | |
9771b263 | 2712 | worklist.release (); |
6e2830c3 | 2713 | delete possibly_undefined_names; |
34f97b94 XDL |
2714 | possibly_undefined_names = NULL; |
2715 | free_dominance_info (CDI_POST_DOMINATORS); | |
2716 | timevar_pop (TV_TREE_UNINIT); | |
2717 | return 0; | |
2718 | } | |
2719 | ||
27a4cd48 DM |
2720 | } // anon namespace |
2721 | ||
2722 | gimple_opt_pass * | |
2723 | make_pass_late_warn_uninitialized (gcc::context *ctxt) | |
2724 | { | |
2725 | return new pass_late_warn_uninitialized (ctxt); | |
2726 | } | |
c152901f | 2727 | |
c152901f AM |
2728 | static unsigned int |
2729 | execute_early_warn_uninitialized (void) | |
2730 | { | |
2731 | /* Currently, this pass runs always but | |
ac0e4fde | 2732 | execute_late_warn_uninitialized only runs with optimization. With |
c152901f AM |
2733 | optimization we want to warn about possible uninitialized as late |
2734 | as possible, thus don't do it here. However, without | |
927734cf | 2735 | optimization we need to warn here about "may be uninitialized". */ |
c152901f AM |
2736 | calculate_dominance_info (CDI_POST_DOMINATORS); |
2737 | ||
2738 | warn_uninitialized_vars (/*warn_possibly_uninitialized=*/!optimize); | |
2739 | ||
67914693 | 2740 | /* Post-dominator information cannot be reliably updated. Free it |
c152901f AM |
2741 | after the use. */ |
2742 | ||
2743 | free_dominance_info (CDI_POST_DOMINATORS); | |
2744 | return 0; | |
2745 | } | |
2746 | ||
c152901f AM |
2747 | namespace { |
2748 | ||
2749 | const pass_data pass_data_early_warn_uninitialized = | |
2750 | { | |
2751 | GIMPLE_PASS, /* type */ | |
2752 | "*early_warn_uninitialized", /* name */ | |
2753 | OPTGROUP_NONE, /* optinfo_flags */ | |
c152901f AM |
2754 | TV_TREE_UNINIT, /* tv_id */ |
2755 | PROP_ssa, /* properties_required */ | |
2756 | 0, /* properties_provided */ | |
2757 | 0, /* properties_destroyed */ | |
2758 | 0, /* todo_flags_start */ | |
2759 | 0, /* todo_flags_finish */ | |
2760 | }; | |
2761 | ||
2762 | class pass_early_warn_uninitialized : public gimple_opt_pass | |
2763 | { | |
2764 | public: | |
c3284718 RS |
2765 | pass_early_warn_uninitialized (gcc::context *ctxt) |
2766 | : gimple_opt_pass (pass_data_early_warn_uninitialized, ctxt) | |
c152901f AM |
2767 | {} |
2768 | ||
2769 | /* opt_pass methods: */ | |
1a3d085c | 2770 | virtual bool gate (function *) { return gate_warn_uninitialized (); } |
be55bfe6 | 2771 | virtual unsigned int execute (function *) |
ac0e4fde ML |
2772 | { |
2773 | return execute_early_warn_uninitialized (); | |
2774 | } | |
c152901f AM |
2775 | |
2776 | }; // class pass_early_warn_uninitialized | |
2777 | ||
2778 | } // anon namespace | |
2779 | ||
2780 | gimple_opt_pass * | |
2781 | make_pass_early_warn_uninitialized (gcc::context *ctxt) | |
2782 | { | |
2783 | return new pass_early_warn_uninitialized (ctxt); | |
2784 | } |