Mercurial > hg > CbC > CbC_gcc
comparison gcc/tree-vrp.c @ 0:a06113de4d67
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author | kent <kent@cr.ie.u-ryukyu.ac.jp> |
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date | Fri, 17 Jul 2009 14:47:48 +0900 |
parents | |
children | 58ad6c70ea60 |
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1 /* Support routines for Value Range Propagation (VRP). | |
2 Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc. | |
3 Contributed by Diego Novillo <dnovillo@redhat.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" | |
24 #include "tm.h" | |
25 #include "ggc.h" | |
26 #include "flags.h" | |
27 #include "tree.h" | |
28 #include "basic-block.h" | |
29 #include "tree-flow.h" | |
30 #include "tree-pass.h" | |
31 #include "tree-dump.h" | |
32 #include "timevar.h" | |
33 #include "diagnostic.h" | |
34 #include "toplev.h" | |
35 #include "intl.h" | |
36 #include "cfgloop.h" | |
37 #include "tree-scalar-evolution.h" | |
38 #include "tree-ssa-propagate.h" | |
39 #include "tree-chrec.h" | |
40 | |
41 | |
42 /* Set of SSA names found live during the RPO traversal of the function | |
43 for still active basic-blocks. */ | |
44 static sbitmap *live; | |
45 | |
46 /* Return true if the SSA name NAME is live on the edge E. */ | |
47 | |
48 static bool | |
49 live_on_edge (edge e, tree name) | |
50 { | |
51 return (live[e->dest->index] | |
52 && TEST_BIT (live[e->dest->index], SSA_NAME_VERSION (name))); | |
53 } | |
54 | |
55 /* Local functions. */ | |
56 static int compare_values (tree val1, tree val2); | |
57 static int compare_values_warnv (tree val1, tree val2, bool *); | |
58 static void vrp_meet (value_range_t *, value_range_t *); | |
59 static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code, | |
60 tree, tree, bool, bool *, | |
61 bool *); | |
62 | |
63 /* Location information for ASSERT_EXPRs. Each instance of this | |
64 structure describes an ASSERT_EXPR for an SSA name. Since a single | |
65 SSA name may have more than one assertion associated with it, these | |
66 locations are kept in a linked list attached to the corresponding | |
67 SSA name. */ | |
68 struct assert_locus_d | |
69 { | |
70 /* Basic block where the assertion would be inserted. */ | |
71 basic_block bb; | |
72 | |
73 /* Some assertions need to be inserted on an edge (e.g., assertions | |
74 generated by COND_EXPRs). In those cases, BB will be NULL. */ | |
75 edge e; | |
76 | |
77 /* Pointer to the statement that generated this assertion. */ | |
78 gimple_stmt_iterator si; | |
79 | |
80 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */ | |
81 enum tree_code comp_code; | |
82 | |
83 /* Value being compared against. */ | |
84 tree val; | |
85 | |
86 /* Expression to compare. */ | |
87 tree expr; | |
88 | |
89 /* Next node in the linked list. */ | |
90 struct assert_locus_d *next; | |
91 }; | |
92 | |
93 typedef struct assert_locus_d *assert_locus_t; | |
94 | |
95 /* If bit I is present, it means that SSA name N_i has a list of | |
96 assertions that should be inserted in the IL. */ | |
97 static bitmap need_assert_for; | |
98 | |
99 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I] | |
100 holds a list of ASSERT_LOCUS_T nodes that describe where | |
101 ASSERT_EXPRs for SSA name N_I should be inserted. */ | |
102 static assert_locus_t *asserts_for; | |
103 | |
104 /* Value range array. After propagation, VR_VALUE[I] holds the range | |
105 of values that SSA name N_I may take. */ | |
106 static value_range_t **vr_value; | |
107 | |
108 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the | |
109 number of executable edges we saw the last time we visited the | |
110 node. */ | |
111 static int *vr_phi_edge_counts; | |
112 | |
113 typedef struct { | |
114 gimple stmt; | |
115 tree vec; | |
116 } switch_update; | |
117 | |
118 static VEC (edge, heap) *to_remove_edges; | |
119 DEF_VEC_O(switch_update); | |
120 DEF_VEC_ALLOC_O(switch_update, heap); | |
121 static VEC (switch_update, heap) *to_update_switch_stmts; | |
122 | |
123 | |
124 /* Return the maximum value for TYPEs base type. */ | |
125 | |
126 static inline tree | |
127 vrp_val_max (const_tree type) | |
128 { | |
129 if (!INTEGRAL_TYPE_P (type)) | |
130 return NULL_TREE; | |
131 | |
132 /* For integer sub-types the values for the base type are relevant. */ | |
133 if (TREE_TYPE (type)) | |
134 type = TREE_TYPE (type); | |
135 | |
136 return TYPE_MAX_VALUE (type); | |
137 } | |
138 | |
139 /* Return the minimum value for TYPEs base type. */ | |
140 | |
141 static inline tree | |
142 vrp_val_min (const_tree type) | |
143 { | |
144 if (!INTEGRAL_TYPE_P (type)) | |
145 return NULL_TREE; | |
146 | |
147 /* For integer sub-types the values for the base type are relevant. */ | |
148 if (TREE_TYPE (type)) | |
149 type = TREE_TYPE (type); | |
150 | |
151 return TYPE_MIN_VALUE (type); | |
152 } | |
153 | |
154 /* Return whether VAL is equal to the maximum value of its type. This | |
155 will be true for a positive overflow infinity. We can't do a | |
156 simple equality comparison with TYPE_MAX_VALUE because C typedefs | |
157 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not == | |
158 to the integer constant with the same value in the type. */ | |
159 | |
160 static inline bool | |
161 vrp_val_is_max (const_tree val) | |
162 { | |
163 tree type_max = vrp_val_max (TREE_TYPE (val)); | |
164 return (val == type_max | |
165 || (type_max != NULL_TREE | |
166 && operand_equal_p (val, type_max, 0))); | |
167 } | |
168 | |
169 /* Return whether VAL is equal to the minimum value of its type. This | |
170 will be true for a negative overflow infinity. */ | |
171 | |
172 static inline bool | |
173 vrp_val_is_min (const_tree val) | |
174 { | |
175 tree type_min = vrp_val_min (TREE_TYPE (val)); | |
176 return (val == type_min | |
177 || (type_min != NULL_TREE | |
178 && operand_equal_p (val, type_min, 0))); | |
179 } | |
180 | |
181 | |
182 /* Return whether TYPE should use an overflow infinity distinct from | |
183 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to | |
184 represent a signed overflow during VRP computations. An infinity | |
185 is distinct from a half-range, which will go from some number to | |
186 TYPE_{MIN,MAX}_VALUE. */ | |
187 | |
188 static inline bool | |
189 needs_overflow_infinity (const_tree type) | |
190 { | |
191 return (INTEGRAL_TYPE_P (type) | |
192 && !TYPE_OVERFLOW_WRAPS (type) | |
193 /* Integer sub-types never overflow as they are never | |
194 operands of arithmetic operators. */ | |
195 && !(TREE_TYPE (type) && TREE_TYPE (type) != type)); | |
196 } | |
197 | |
198 /* Return whether TYPE can support our overflow infinity | |
199 representation: we use the TREE_OVERFLOW flag, which only exists | |
200 for constants. If TYPE doesn't support this, we don't optimize | |
201 cases which would require signed overflow--we drop them to | |
202 VARYING. */ | |
203 | |
204 static inline bool | |
205 supports_overflow_infinity (const_tree type) | |
206 { | |
207 tree min = vrp_val_min (type), max = vrp_val_max (type); | |
208 #ifdef ENABLE_CHECKING | |
209 gcc_assert (needs_overflow_infinity (type)); | |
210 #endif | |
211 return (min != NULL_TREE | |
212 && CONSTANT_CLASS_P (min) | |
213 && max != NULL_TREE | |
214 && CONSTANT_CLASS_P (max)); | |
215 } | |
216 | |
217 /* VAL is the maximum or minimum value of a type. Return a | |
218 corresponding overflow infinity. */ | |
219 | |
220 static inline tree | |
221 make_overflow_infinity (tree val) | |
222 { | |
223 #ifdef ENABLE_CHECKING | |
224 gcc_assert (val != NULL_TREE && CONSTANT_CLASS_P (val)); | |
225 #endif | |
226 val = copy_node (val); | |
227 TREE_OVERFLOW (val) = 1; | |
228 return val; | |
229 } | |
230 | |
231 /* Return a negative overflow infinity for TYPE. */ | |
232 | |
233 static inline tree | |
234 negative_overflow_infinity (tree type) | |
235 { | |
236 #ifdef ENABLE_CHECKING | |
237 gcc_assert (supports_overflow_infinity (type)); | |
238 #endif | |
239 return make_overflow_infinity (vrp_val_min (type)); | |
240 } | |
241 | |
242 /* Return a positive overflow infinity for TYPE. */ | |
243 | |
244 static inline tree | |
245 positive_overflow_infinity (tree type) | |
246 { | |
247 #ifdef ENABLE_CHECKING | |
248 gcc_assert (supports_overflow_infinity (type)); | |
249 #endif | |
250 return make_overflow_infinity (vrp_val_max (type)); | |
251 } | |
252 | |
253 /* Return whether VAL is a negative overflow infinity. */ | |
254 | |
255 static inline bool | |
256 is_negative_overflow_infinity (const_tree val) | |
257 { | |
258 return (needs_overflow_infinity (TREE_TYPE (val)) | |
259 && CONSTANT_CLASS_P (val) | |
260 && TREE_OVERFLOW (val) | |
261 && vrp_val_is_min (val)); | |
262 } | |
263 | |
264 /* Return whether VAL is a positive overflow infinity. */ | |
265 | |
266 static inline bool | |
267 is_positive_overflow_infinity (const_tree val) | |
268 { | |
269 return (needs_overflow_infinity (TREE_TYPE (val)) | |
270 && CONSTANT_CLASS_P (val) | |
271 && TREE_OVERFLOW (val) | |
272 && vrp_val_is_max (val)); | |
273 } | |
274 | |
275 /* Return whether VAL is a positive or negative overflow infinity. */ | |
276 | |
277 static inline bool | |
278 is_overflow_infinity (const_tree val) | |
279 { | |
280 return (needs_overflow_infinity (TREE_TYPE (val)) | |
281 && CONSTANT_CLASS_P (val) | |
282 && TREE_OVERFLOW (val) | |
283 && (vrp_val_is_min (val) || vrp_val_is_max (val))); | |
284 } | |
285 | |
286 /* Return whether STMT has a constant rhs that is_overflow_infinity. */ | |
287 | |
288 static inline bool | |
289 stmt_overflow_infinity (gimple stmt) | |
290 { | |
291 if (is_gimple_assign (stmt) | |
292 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) == | |
293 GIMPLE_SINGLE_RHS) | |
294 return is_overflow_infinity (gimple_assign_rhs1 (stmt)); | |
295 return false; | |
296 } | |
297 | |
298 /* If VAL is now an overflow infinity, return VAL. Otherwise, return | |
299 the same value with TREE_OVERFLOW clear. This can be used to avoid | |
300 confusing a regular value with an overflow value. */ | |
301 | |
302 static inline tree | |
303 avoid_overflow_infinity (tree val) | |
304 { | |
305 if (!is_overflow_infinity (val)) | |
306 return val; | |
307 | |
308 if (vrp_val_is_max (val)) | |
309 return vrp_val_max (TREE_TYPE (val)); | |
310 else | |
311 { | |
312 #ifdef ENABLE_CHECKING | |
313 gcc_assert (vrp_val_is_min (val)); | |
314 #endif | |
315 return vrp_val_min (TREE_TYPE (val)); | |
316 } | |
317 } | |
318 | |
319 | |
320 /* Return true if ARG is marked with the nonnull attribute in the | |
321 current function signature. */ | |
322 | |
323 static bool | |
324 nonnull_arg_p (const_tree arg) | |
325 { | |
326 tree t, attrs, fntype; | |
327 unsigned HOST_WIDE_INT arg_num; | |
328 | |
329 gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg))); | |
330 | |
331 /* The static chain decl is always non null. */ | |
332 if (arg == cfun->static_chain_decl) | |
333 return true; | |
334 | |
335 fntype = TREE_TYPE (current_function_decl); | |
336 attrs = lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype)); | |
337 | |
338 /* If "nonnull" wasn't specified, we know nothing about the argument. */ | |
339 if (attrs == NULL_TREE) | |
340 return false; | |
341 | |
342 /* If "nonnull" applies to all the arguments, then ARG is non-null. */ | |
343 if (TREE_VALUE (attrs) == NULL_TREE) | |
344 return true; | |
345 | |
346 /* Get the position number for ARG in the function signature. */ | |
347 for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl); | |
348 t; | |
349 t = TREE_CHAIN (t), arg_num++) | |
350 { | |
351 if (t == arg) | |
352 break; | |
353 } | |
354 | |
355 gcc_assert (t == arg); | |
356 | |
357 /* Now see if ARG_NUM is mentioned in the nonnull list. */ | |
358 for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t)) | |
359 { | |
360 if (compare_tree_int (TREE_VALUE (t), arg_num) == 0) | |
361 return true; | |
362 } | |
363 | |
364 return false; | |
365 } | |
366 | |
367 | |
368 /* Set value range VR to VR_VARYING. */ | |
369 | |
370 static inline void | |
371 set_value_range_to_varying (value_range_t *vr) | |
372 { | |
373 vr->type = VR_VARYING; | |
374 vr->min = vr->max = NULL_TREE; | |
375 if (vr->equiv) | |
376 bitmap_clear (vr->equiv); | |
377 } | |
378 | |
379 | |
380 /* Set value range VR to {T, MIN, MAX, EQUIV}. */ | |
381 | |
382 static void | |
383 set_value_range (value_range_t *vr, enum value_range_type t, tree min, | |
384 tree max, bitmap equiv) | |
385 { | |
386 #if defined ENABLE_CHECKING | |
387 /* Check the validity of the range. */ | |
388 if (t == VR_RANGE || t == VR_ANTI_RANGE) | |
389 { | |
390 int cmp; | |
391 | |
392 gcc_assert (min && max); | |
393 | |
394 if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE) | |
395 gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max)); | |
396 | |
397 cmp = compare_values (min, max); | |
398 gcc_assert (cmp == 0 || cmp == -1 || cmp == -2); | |
399 | |
400 if (needs_overflow_infinity (TREE_TYPE (min))) | |
401 gcc_assert (!is_overflow_infinity (min) | |
402 || !is_overflow_infinity (max)); | |
403 } | |
404 | |
405 if (t == VR_UNDEFINED || t == VR_VARYING) | |
406 gcc_assert (min == NULL_TREE && max == NULL_TREE); | |
407 | |
408 if (t == VR_UNDEFINED || t == VR_VARYING) | |
409 gcc_assert (equiv == NULL || bitmap_empty_p (equiv)); | |
410 #endif | |
411 | |
412 vr->type = t; | |
413 vr->min = min; | |
414 vr->max = max; | |
415 | |
416 /* Since updating the equivalence set involves deep copying the | |
417 bitmaps, only do it if absolutely necessary. */ | |
418 if (vr->equiv == NULL | |
419 && equiv != NULL) | |
420 vr->equiv = BITMAP_ALLOC (NULL); | |
421 | |
422 if (equiv != vr->equiv) | |
423 { | |
424 if (equiv && !bitmap_empty_p (equiv)) | |
425 bitmap_copy (vr->equiv, equiv); | |
426 else | |
427 bitmap_clear (vr->equiv); | |
428 } | |
429 } | |
430 | |
431 | |
432 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}. | |
433 This means adjusting T, MIN and MAX representing the case of a | |
434 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX] | |
435 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges. | |
436 In corner cases where MAX+1 or MIN-1 wraps this will fall back | |
437 to varying. | |
438 This routine exists to ease canonicalization in the case where we | |
439 extract ranges from var + CST op limit. */ | |
440 | |
441 static void | |
442 set_and_canonicalize_value_range (value_range_t *vr, enum value_range_type t, | |
443 tree min, tree max, bitmap equiv) | |
444 { | |
445 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */ | |
446 if ((t != VR_RANGE | |
447 && t != VR_ANTI_RANGE) | |
448 || TREE_CODE (min) != INTEGER_CST | |
449 || TREE_CODE (max) != INTEGER_CST) | |
450 { | |
451 set_value_range (vr, t, min, max, equiv); | |
452 return; | |
453 } | |
454 | |
455 /* Wrong order for min and max, to swap them and the VR type we need | |
456 to adjust them. */ | |
457 if (tree_int_cst_lt (max, min)) | |
458 { | |
459 tree one = build_int_cst (TREE_TYPE (min), 1); | |
460 tree tmp = int_const_binop (PLUS_EXPR, max, one, 0); | |
461 max = int_const_binop (MINUS_EXPR, min, one, 0); | |
462 min = tmp; | |
463 | |
464 /* There's one corner case, if we had [C+1, C] before we now have | |
465 that again. But this represents an empty value range, so drop | |
466 to varying in this case. */ | |
467 if (tree_int_cst_lt (max, min)) | |
468 { | |
469 set_value_range_to_varying (vr); | |
470 return; | |
471 } | |
472 | |
473 t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE; | |
474 } | |
475 | |
476 /* Anti-ranges that can be represented as ranges should be so. */ | |
477 if (t == VR_ANTI_RANGE) | |
478 { | |
479 bool is_min = vrp_val_is_min (min); | |
480 bool is_max = vrp_val_is_max (max); | |
481 | |
482 if (is_min && is_max) | |
483 { | |
484 /* We cannot deal with empty ranges, drop to varying. */ | |
485 set_value_range_to_varying (vr); | |
486 return; | |
487 } | |
488 else if (is_min | |
489 /* As a special exception preserve non-null ranges. */ | |
490 && !(TYPE_UNSIGNED (TREE_TYPE (min)) | |
491 && integer_zerop (max))) | |
492 { | |
493 tree one = build_int_cst (TREE_TYPE (max), 1); | |
494 min = int_const_binop (PLUS_EXPR, max, one, 0); | |
495 max = vrp_val_max (TREE_TYPE (max)); | |
496 t = VR_RANGE; | |
497 } | |
498 else if (is_max) | |
499 { | |
500 tree one = build_int_cst (TREE_TYPE (min), 1); | |
501 max = int_const_binop (MINUS_EXPR, min, one, 0); | |
502 min = vrp_val_min (TREE_TYPE (min)); | |
503 t = VR_RANGE; | |
504 } | |
505 } | |
506 | |
507 set_value_range (vr, t, min, max, equiv); | |
508 } | |
509 | |
510 /* Copy value range FROM into value range TO. */ | |
511 | |
512 static inline void | |
513 copy_value_range (value_range_t *to, value_range_t *from) | |
514 { | |
515 set_value_range (to, from->type, from->min, from->max, from->equiv); | |
516 } | |
517 | |
518 /* Set value range VR to a single value. This function is only called | |
519 with values we get from statements, and exists to clear the | |
520 TREE_OVERFLOW flag so that we don't think we have an overflow | |
521 infinity when we shouldn't. */ | |
522 | |
523 static inline void | |
524 set_value_range_to_value (value_range_t *vr, tree val, bitmap equiv) | |
525 { | |
526 gcc_assert (is_gimple_min_invariant (val)); | |
527 val = avoid_overflow_infinity (val); | |
528 set_value_range (vr, VR_RANGE, val, val, equiv); | |
529 } | |
530 | |
531 /* Set value range VR to a non-negative range of type TYPE. | |
532 OVERFLOW_INFINITY indicates whether to use an overflow infinity | |
533 rather than TYPE_MAX_VALUE; this should be true if we determine | |
534 that the range is nonnegative based on the assumption that signed | |
535 overflow does not occur. */ | |
536 | |
537 static inline void | |
538 set_value_range_to_nonnegative (value_range_t *vr, tree type, | |
539 bool overflow_infinity) | |
540 { | |
541 tree zero; | |
542 | |
543 if (overflow_infinity && !supports_overflow_infinity (type)) | |
544 { | |
545 set_value_range_to_varying (vr); | |
546 return; | |
547 } | |
548 | |
549 zero = build_int_cst (type, 0); | |
550 set_value_range (vr, VR_RANGE, zero, | |
551 (overflow_infinity | |
552 ? positive_overflow_infinity (type) | |
553 : TYPE_MAX_VALUE (type)), | |
554 vr->equiv); | |
555 } | |
556 | |
557 /* Set value range VR to a non-NULL range of type TYPE. */ | |
558 | |
559 static inline void | |
560 set_value_range_to_nonnull (value_range_t *vr, tree type) | |
561 { | |
562 tree zero = build_int_cst (type, 0); | |
563 set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv); | |
564 } | |
565 | |
566 | |
567 /* Set value range VR to a NULL range of type TYPE. */ | |
568 | |
569 static inline void | |
570 set_value_range_to_null (value_range_t *vr, tree type) | |
571 { | |
572 set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv); | |
573 } | |
574 | |
575 | |
576 /* Set value range VR to a range of a truthvalue of type TYPE. */ | |
577 | |
578 static inline void | |
579 set_value_range_to_truthvalue (value_range_t *vr, tree type) | |
580 { | |
581 if (TYPE_PRECISION (type) == 1) | |
582 set_value_range_to_varying (vr); | |
583 else | |
584 set_value_range (vr, VR_RANGE, | |
585 build_int_cst (type, 0), build_int_cst (type, 1), | |
586 vr->equiv); | |
587 } | |
588 | |
589 | |
590 /* Set value range VR to VR_UNDEFINED. */ | |
591 | |
592 static inline void | |
593 set_value_range_to_undefined (value_range_t *vr) | |
594 { | |
595 vr->type = VR_UNDEFINED; | |
596 vr->min = vr->max = NULL_TREE; | |
597 if (vr->equiv) | |
598 bitmap_clear (vr->equiv); | |
599 } | |
600 | |
601 | |
602 /* If abs (min) < abs (max), set VR to [-max, max], if | |
603 abs (min) >= abs (max), set VR to [-min, min]. */ | |
604 | |
605 static void | |
606 abs_extent_range (value_range_t *vr, tree min, tree max) | |
607 { | |
608 int cmp; | |
609 | |
610 gcc_assert (TREE_CODE (min) == INTEGER_CST); | |
611 gcc_assert (TREE_CODE (max) == INTEGER_CST); | |
612 gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min))); | |
613 gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min))); | |
614 min = fold_unary (ABS_EXPR, TREE_TYPE (min), min); | |
615 max = fold_unary (ABS_EXPR, TREE_TYPE (max), max); | |
616 if (TREE_OVERFLOW (min) || TREE_OVERFLOW (max)) | |
617 { | |
618 set_value_range_to_varying (vr); | |
619 return; | |
620 } | |
621 cmp = compare_values (min, max); | |
622 if (cmp == -1) | |
623 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), max); | |
624 else if (cmp == 0 || cmp == 1) | |
625 { | |
626 max = min; | |
627 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), min); | |
628 } | |
629 else | |
630 { | |
631 set_value_range_to_varying (vr); | |
632 return; | |
633 } | |
634 set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL); | |
635 } | |
636 | |
637 | |
638 /* Return value range information for VAR. | |
639 | |
640 If we have no values ranges recorded (ie, VRP is not running), then | |
641 return NULL. Otherwise create an empty range if none existed for VAR. */ | |
642 | |
643 static value_range_t * | |
644 get_value_range (const_tree var) | |
645 { | |
646 value_range_t *vr; | |
647 tree sym; | |
648 unsigned ver = SSA_NAME_VERSION (var); | |
649 | |
650 /* If we have no recorded ranges, then return NULL. */ | |
651 if (! vr_value) | |
652 return NULL; | |
653 | |
654 vr = vr_value[ver]; | |
655 if (vr) | |
656 return vr; | |
657 | |
658 /* Create a default value range. */ | |
659 vr_value[ver] = vr = XCNEW (value_range_t); | |
660 | |
661 /* Defer allocating the equivalence set. */ | |
662 vr->equiv = NULL; | |
663 | |
664 /* If VAR is a default definition, the variable can take any value | |
665 in VAR's type. */ | |
666 sym = SSA_NAME_VAR (var); | |
667 if (SSA_NAME_IS_DEFAULT_DEF (var)) | |
668 { | |
669 /* Try to use the "nonnull" attribute to create ~[0, 0] | |
670 anti-ranges for pointers. Note that this is only valid with | |
671 default definitions of PARM_DECLs. */ | |
672 if (TREE_CODE (sym) == PARM_DECL | |
673 && POINTER_TYPE_P (TREE_TYPE (sym)) | |
674 && nonnull_arg_p (sym)) | |
675 set_value_range_to_nonnull (vr, TREE_TYPE (sym)); | |
676 else | |
677 set_value_range_to_varying (vr); | |
678 } | |
679 | |
680 return vr; | |
681 } | |
682 | |
683 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */ | |
684 | |
685 static inline bool | |
686 vrp_operand_equal_p (const_tree val1, const_tree val2) | |
687 { | |
688 if (val1 == val2) | |
689 return true; | |
690 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0)) | |
691 return false; | |
692 if (is_overflow_infinity (val1)) | |
693 return is_overflow_infinity (val2); | |
694 return true; | |
695 } | |
696 | |
697 /* Return true, if the bitmaps B1 and B2 are equal. */ | |
698 | |
699 static inline bool | |
700 vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2) | |
701 { | |
702 return (b1 == b2 | |
703 || (b1 && b2 | |
704 && bitmap_equal_p (b1, b2))); | |
705 } | |
706 | |
707 /* Update the value range and equivalence set for variable VAR to | |
708 NEW_VR. Return true if NEW_VR is different from VAR's previous | |
709 value. | |
710 | |
711 NOTE: This function assumes that NEW_VR is a temporary value range | |
712 object created for the sole purpose of updating VAR's range. The | |
713 storage used by the equivalence set from NEW_VR will be freed by | |
714 this function. Do not call update_value_range when NEW_VR | |
715 is the range object associated with another SSA name. */ | |
716 | |
717 static inline bool | |
718 update_value_range (const_tree var, value_range_t *new_vr) | |
719 { | |
720 value_range_t *old_vr; | |
721 bool is_new; | |
722 | |
723 /* Update the value range, if necessary. */ | |
724 old_vr = get_value_range (var); | |
725 is_new = old_vr->type != new_vr->type | |
726 || !vrp_operand_equal_p (old_vr->min, new_vr->min) | |
727 || !vrp_operand_equal_p (old_vr->max, new_vr->max) | |
728 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv); | |
729 | |
730 if (is_new) | |
731 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max, | |
732 new_vr->equiv); | |
733 | |
734 BITMAP_FREE (new_vr->equiv); | |
735 | |
736 return is_new; | |
737 } | |
738 | |
739 | |
740 /* Add VAR and VAR's equivalence set to EQUIV. This is the central | |
741 point where equivalence processing can be turned on/off. */ | |
742 | |
743 static void | |
744 add_equivalence (bitmap *equiv, const_tree var) | |
745 { | |
746 unsigned ver = SSA_NAME_VERSION (var); | |
747 value_range_t *vr = vr_value[ver]; | |
748 | |
749 if (*equiv == NULL) | |
750 *equiv = BITMAP_ALLOC (NULL); | |
751 bitmap_set_bit (*equiv, ver); | |
752 if (vr && vr->equiv) | |
753 bitmap_ior_into (*equiv, vr->equiv); | |
754 } | |
755 | |
756 | |
757 /* Return true if VR is ~[0, 0]. */ | |
758 | |
759 static inline bool | |
760 range_is_nonnull (value_range_t *vr) | |
761 { | |
762 return vr->type == VR_ANTI_RANGE | |
763 && integer_zerop (vr->min) | |
764 && integer_zerop (vr->max); | |
765 } | |
766 | |
767 | |
768 /* Return true if VR is [0, 0]. */ | |
769 | |
770 static inline bool | |
771 range_is_null (value_range_t *vr) | |
772 { | |
773 return vr->type == VR_RANGE | |
774 && integer_zerop (vr->min) | |
775 && integer_zerop (vr->max); | |
776 } | |
777 | |
778 | |
779 /* Return true if value range VR involves at least one symbol. */ | |
780 | |
781 static inline bool | |
782 symbolic_range_p (value_range_t *vr) | |
783 { | |
784 return (!is_gimple_min_invariant (vr->min) | |
785 || !is_gimple_min_invariant (vr->max)); | |
786 } | |
787 | |
788 /* Return true if value range VR uses an overflow infinity. */ | |
789 | |
790 static inline bool | |
791 overflow_infinity_range_p (value_range_t *vr) | |
792 { | |
793 return (vr->type == VR_RANGE | |
794 && (is_overflow_infinity (vr->min) | |
795 || is_overflow_infinity (vr->max))); | |
796 } | |
797 | |
798 /* Return false if we can not make a valid comparison based on VR; | |
799 this will be the case if it uses an overflow infinity and overflow | |
800 is not undefined (i.e., -fno-strict-overflow is in effect). | |
801 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR | |
802 uses an overflow infinity. */ | |
803 | |
804 static bool | |
805 usable_range_p (value_range_t *vr, bool *strict_overflow_p) | |
806 { | |
807 gcc_assert (vr->type == VR_RANGE); | |
808 if (is_overflow_infinity (vr->min)) | |
809 { | |
810 *strict_overflow_p = true; | |
811 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min))) | |
812 return false; | |
813 } | |
814 if (is_overflow_infinity (vr->max)) | |
815 { | |
816 *strict_overflow_p = true; | |
817 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max))) | |
818 return false; | |
819 } | |
820 return true; | |
821 } | |
822 | |
823 | |
824 /* Like tree_expr_nonnegative_warnv_p, but this function uses value | |
825 ranges obtained so far. */ | |
826 | |
827 static bool | |
828 vrp_expr_computes_nonnegative (tree expr, bool *strict_overflow_p) | |
829 { | |
830 return (tree_expr_nonnegative_warnv_p (expr, strict_overflow_p) | |
831 || (TREE_CODE (expr) == SSA_NAME | |
832 && ssa_name_nonnegative_p (expr))); | |
833 } | |
834 | |
835 /* Return true if the result of assignment STMT is know to be non-negative. | |
836 If the return value is based on the assumption that signed overflow is | |
837 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change | |
838 *STRICT_OVERFLOW_P.*/ | |
839 | |
840 static bool | |
841 gimple_assign_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p) | |
842 { | |
843 enum tree_code code = gimple_assign_rhs_code (stmt); | |
844 switch (get_gimple_rhs_class (code)) | |
845 { | |
846 case GIMPLE_UNARY_RHS: | |
847 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt), | |
848 gimple_expr_type (stmt), | |
849 gimple_assign_rhs1 (stmt), | |
850 strict_overflow_p); | |
851 case GIMPLE_BINARY_RHS: | |
852 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt), | |
853 gimple_expr_type (stmt), | |
854 gimple_assign_rhs1 (stmt), | |
855 gimple_assign_rhs2 (stmt), | |
856 strict_overflow_p); | |
857 case GIMPLE_SINGLE_RHS: | |
858 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt), | |
859 strict_overflow_p); | |
860 case GIMPLE_INVALID_RHS: | |
861 gcc_unreachable (); | |
862 default: | |
863 gcc_unreachable (); | |
864 } | |
865 } | |
866 | |
867 /* Return true if return value of call STMT is know to be non-negative. | |
868 If the return value is based on the assumption that signed overflow is | |
869 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change | |
870 *STRICT_OVERFLOW_P.*/ | |
871 | |
872 static bool | |
873 gimple_call_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p) | |
874 { | |
875 tree arg0 = gimple_call_num_args (stmt) > 0 ? | |
876 gimple_call_arg (stmt, 0) : NULL_TREE; | |
877 tree arg1 = gimple_call_num_args (stmt) > 1 ? | |
878 gimple_call_arg (stmt, 1) : NULL_TREE; | |
879 | |
880 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt), | |
881 gimple_call_fndecl (stmt), | |
882 arg0, | |
883 arg1, | |
884 strict_overflow_p); | |
885 } | |
886 | |
887 /* Return true if STMT is know to to compute a non-negative value. | |
888 If the return value is based on the assumption that signed overflow is | |
889 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change | |
890 *STRICT_OVERFLOW_P.*/ | |
891 | |
892 static bool | |
893 gimple_stmt_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p) | |
894 { | |
895 switch (gimple_code (stmt)) | |
896 { | |
897 case GIMPLE_ASSIGN: | |
898 return gimple_assign_nonnegative_warnv_p (stmt, strict_overflow_p); | |
899 case GIMPLE_CALL: | |
900 return gimple_call_nonnegative_warnv_p (stmt, strict_overflow_p); | |
901 default: | |
902 gcc_unreachable (); | |
903 } | |
904 } | |
905 | |
906 /* Return true if the result of assignment STMT is know to be non-zero. | |
907 If the return value is based on the assumption that signed overflow is | |
908 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change | |
909 *STRICT_OVERFLOW_P.*/ | |
910 | |
911 static bool | |
912 gimple_assign_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p) | |
913 { | |
914 enum tree_code code = gimple_assign_rhs_code (stmt); | |
915 switch (get_gimple_rhs_class (code)) | |
916 { | |
917 case GIMPLE_UNARY_RHS: | |
918 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt), | |
919 gimple_expr_type (stmt), | |
920 gimple_assign_rhs1 (stmt), | |
921 strict_overflow_p); | |
922 case GIMPLE_BINARY_RHS: | |
923 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt), | |
924 gimple_expr_type (stmt), | |
925 gimple_assign_rhs1 (stmt), | |
926 gimple_assign_rhs2 (stmt), | |
927 strict_overflow_p); | |
928 case GIMPLE_SINGLE_RHS: | |
929 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt), | |
930 strict_overflow_p); | |
931 case GIMPLE_INVALID_RHS: | |
932 gcc_unreachable (); | |
933 default: | |
934 gcc_unreachable (); | |
935 } | |
936 } | |
937 | |
938 /* Return true if STMT is know to to compute a non-zero value. | |
939 If the return value is based on the assumption that signed overflow is | |
940 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change | |
941 *STRICT_OVERFLOW_P.*/ | |
942 | |
943 static bool | |
944 gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p) | |
945 { | |
946 switch (gimple_code (stmt)) | |
947 { | |
948 case GIMPLE_ASSIGN: | |
949 return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p); | |
950 case GIMPLE_CALL: | |
951 return gimple_alloca_call_p (stmt); | |
952 default: | |
953 gcc_unreachable (); | |
954 } | |
955 } | |
956 | |
957 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges | |
958 obtained so far. */ | |
959 | |
960 static bool | |
961 vrp_stmt_computes_nonzero (gimple stmt, bool *strict_overflow_p) | |
962 { | |
963 if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p)) | |
964 return true; | |
965 | |
966 /* If we have an expression of the form &X->a, then the expression | |
967 is nonnull if X is nonnull. */ | |
968 if (is_gimple_assign (stmt) | |
969 && gimple_assign_rhs_code (stmt) == ADDR_EXPR) | |
970 { | |
971 tree expr = gimple_assign_rhs1 (stmt); | |
972 tree base = get_base_address (TREE_OPERAND (expr, 0)); | |
973 | |
974 if (base != NULL_TREE | |
975 && TREE_CODE (base) == INDIRECT_REF | |
976 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME) | |
977 { | |
978 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0)); | |
979 if (range_is_nonnull (vr)) | |
980 return true; | |
981 } | |
982 } | |
983 | |
984 return false; | |
985 } | |
986 | |
987 /* Returns true if EXPR is a valid value (as expected by compare_values) -- | |
988 a gimple invariant, or SSA_NAME +- CST. */ | |
989 | |
990 static bool | |
991 valid_value_p (tree expr) | |
992 { | |
993 if (TREE_CODE (expr) == SSA_NAME) | |
994 return true; | |
995 | |
996 if (TREE_CODE (expr) == PLUS_EXPR | |
997 || TREE_CODE (expr) == MINUS_EXPR) | |
998 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME | |
999 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST); | |
1000 | |
1001 return is_gimple_min_invariant (expr); | |
1002 } | |
1003 | |
1004 /* Return | |
1005 1 if VAL < VAL2 | |
1006 0 if !(VAL < VAL2) | |
1007 -2 if those are incomparable. */ | |
1008 static inline int | |
1009 operand_less_p (tree val, tree val2) | |
1010 { | |
1011 /* LT is folded faster than GE and others. Inline the common case. */ | |
1012 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST) | |
1013 { | |
1014 if (TYPE_UNSIGNED (TREE_TYPE (val))) | |
1015 return INT_CST_LT_UNSIGNED (val, val2); | |
1016 else | |
1017 { | |
1018 if (INT_CST_LT (val, val2)) | |
1019 return 1; | |
1020 } | |
1021 } | |
1022 else | |
1023 { | |
1024 tree tcmp; | |
1025 | |
1026 fold_defer_overflow_warnings (); | |
1027 | |
1028 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2); | |
1029 | |
1030 fold_undefer_and_ignore_overflow_warnings (); | |
1031 | |
1032 if (!tcmp | |
1033 || TREE_CODE (tcmp) != INTEGER_CST) | |
1034 return -2; | |
1035 | |
1036 if (!integer_zerop (tcmp)) | |
1037 return 1; | |
1038 } | |
1039 | |
1040 /* val >= val2, not considering overflow infinity. */ | |
1041 if (is_negative_overflow_infinity (val)) | |
1042 return is_negative_overflow_infinity (val2) ? 0 : 1; | |
1043 else if (is_positive_overflow_infinity (val2)) | |
1044 return is_positive_overflow_infinity (val) ? 0 : 1; | |
1045 | |
1046 return 0; | |
1047 } | |
1048 | |
1049 /* Compare two values VAL1 and VAL2. Return | |
1050 | |
1051 -2 if VAL1 and VAL2 cannot be compared at compile-time, | |
1052 -1 if VAL1 < VAL2, | |
1053 0 if VAL1 == VAL2, | |
1054 +1 if VAL1 > VAL2, and | |
1055 +2 if VAL1 != VAL2 | |
1056 | |
1057 This is similar to tree_int_cst_compare but supports pointer values | |
1058 and values that cannot be compared at compile time. | |
1059 | |
1060 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to | |
1061 true if the return value is only valid if we assume that signed | |
1062 overflow is undefined. */ | |
1063 | |
1064 static int | |
1065 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p) | |
1066 { | |
1067 if (val1 == val2) | |
1068 return 0; | |
1069 | |
1070 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or | |
1071 both integers. */ | |
1072 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1)) | |
1073 == POINTER_TYPE_P (TREE_TYPE (val2))); | |
1074 /* Convert the two values into the same type. This is needed because | |
1075 sizetype causes sign extension even for unsigned types. */ | |
1076 val2 = fold_convert (TREE_TYPE (val1), val2); | |
1077 STRIP_USELESS_TYPE_CONVERSION (val2); | |
1078 | |
1079 if ((TREE_CODE (val1) == SSA_NAME | |
1080 || TREE_CODE (val1) == PLUS_EXPR | |
1081 || TREE_CODE (val1) == MINUS_EXPR) | |
1082 && (TREE_CODE (val2) == SSA_NAME | |
1083 || TREE_CODE (val2) == PLUS_EXPR | |
1084 || TREE_CODE (val2) == MINUS_EXPR)) | |
1085 { | |
1086 tree n1, c1, n2, c2; | |
1087 enum tree_code code1, code2; | |
1088 | |
1089 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME', | |
1090 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the | |
1091 same name, return -2. */ | |
1092 if (TREE_CODE (val1) == SSA_NAME) | |
1093 { | |
1094 code1 = SSA_NAME; | |
1095 n1 = val1; | |
1096 c1 = NULL_TREE; | |
1097 } | |
1098 else | |
1099 { | |
1100 code1 = TREE_CODE (val1); | |
1101 n1 = TREE_OPERAND (val1, 0); | |
1102 c1 = TREE_OPERAND (val1, 1); | |
1103 if (tree_int_cst_sgn (c1) == -1) | |
1104 { | |
1105 if (is_negative_overflow_infinity (c1)) | |
1106 return -2; | |
1107 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1); | |
1108 if (!c1) | |
1109 return -2; | |
1110 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR; | |
1111 } | |
1112 } | |
1113 | |
1114 if (TREE_CODE (val2) == SSA_NAME) | |
1115 { | |
1116 code2 = SSA_NAME; | |
1117 n2 = val2; | |
1118 c2 = NULL_TREE; | |
1119 } | |
1120 else | |
1121 { | |
1122 code2 = TREE_CODE (val2); | |
1123 n2 = TREE_OPERAND (val2, 0); | |
1124 c2 = TREE_OPERAND (val2, 1); | |
1125 if (tree_int_cst_sgn (c2) == -1) | |
1126 { | |
1127 if (is_negative_overflow_infinity (c2)) | |
1128 return -2; | |
1129 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2); | |
1130 if (!c2) | |
1131 return -2; | |
1132 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR; | |
1133 } | |
1134 } | |
1135 | |
1136 /* Both values must use the same name. */ | |
1137 if (n1 != n2) | |
1138 return -2; | |
1139 | |
1140 if (code1 == SSA_NAME | |
1141 && code2 == SSA_NAME) | |
1142 /* NAME == NAME */ | |
1143 return 0; | |
1144 | |
1145 /* If overflow is defined we cannot simplify more. */ | |
1146 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1))) | |
1147 return -2; | |
1148 | |
1149 if (strict_overflow_p != NULL | |
1150 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1)) | |
1151 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2))) | |
1152 *strict_overflow_p = true; | |
1153 | |
1154 if (code1 == SSA_NAME) | |
1155 { | |
1156 if (code2 == PLUS_EXPR) | |
1157 /* NAME < NAME + CST */ | |
1158 return -1; | |
1159 else if (code2 == MINUS_EXPR) | |
1160 /* NAME > NAME - CST */ | |
1161 return 1; | |
1162 } | |
1163 else if (code1 == PLUS_EXPR) | |
1164 { | |
1165 if (code2 == SSA_NAME) | |
1166 /* NAME + CST > NAME */ | |
1167 return 1; | |
1168 else if (code2 == PLUS_EXPR) | |
1169 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */ | |
1170 return compare_values_warnv (c1, c2, strict_overflow_p); | |
1171 else if (code2 == MINUS_EXPR) | |
1172 /* NAME + CST1 > NAME - CST2 */ | |
1173 return 1; | |
1174 } | |
1175 else if (code1 == MINUS_EXPR) | |
1176 { | |
1177 if (code2 == SSA_NAME) | |
1178 /* NAME - CST < NAME */ | |
1179 return -1; | |
1180 else if (code2 == PLUS_EXPR) | |
1181 /* NAME - CST1 < NAME + CST2 */ | |
1182 return -1; | |
1183 else if (code2 == MINUS_EXPR) | |
1184 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that | |
1185 C1 and C2 are swapped in the call to compare_values. */ | |
1186 return compare_values_warnv (c2, c1, strict_overflow_p); | |
1187 } | |
1188 | |
1189 gcc_unreachable (); | |
1190 } | |
1191 | |
1192 /* We cannot compare non-constants. */ | |
1193 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)) | |
1194 return -2; | |
1195 | |
1196 if (!POINTER_TYPE_P (TREE_TYPE (val1))) | |
1197 { | |
1198 /* We cannot compare overflowed values, except for overflow | |
1199 infinities. */ | |
1200 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2)) | |
1201 { | |
1202 if (strict_overflow_p != NULL) | |
1203 *strict_overflow_p = true; | |
1204 if (is_negative_overflow_infinity (val1)) | |
1205 return is_negative_overflow_infinity (val2) ? 0 : -1; | |
1206 else if (is_negative_overflow_infinity (val2)) | |
1207 return 1; | |
1208 else if (is_positive_overflow_infinity (val1)) | |
1209 return is_positive_overflow_infinity (val2) ? 0 : 1; | |
1210 else if (is_positive_overflow_infinity (val2)) | |
1211 return -1; | |
1212 return -2; | |
1213 } | |
1214 | |
1215 return tree_int_cst_compare (val1, val2); | |
1216 } | |
1217 else | |
1218 { | |
1219 tree t; | |
1220 | |
1221 /* First see if VAL1 and VAL2 are not the same. */ | |
1222 if (val1 == val2 || operand_equal_p (val1, val2, 0)) | |
1223 return 0; | |
1224 | |
1225 /* If VAL1 is a lower address than VAL2, return -1. */ | |
1226 if (operand_less_p (val1, val2) == 1) | |
1227 return -1; | |
1228 | |
1229 /* If VAL1 is a higher address than VAL2, return +1. */ | |
1230 if (operand_less_p (val2, val1) == 1) | |
1231 return 1; | |
1232 | |
1233 /* If VAL1 is different than VAL2, return +2. | |
1234 For integer constants we either have already returned -1 or 1 | |
1235 or they are equivalent. We still might succeed in proving | |
1236 something about non-trivial operands. */ | |
1237 if (TREE_CODE (val1) != INTEGER_CST | |
1238 || TREE_CODE (val2) != INTEGER_CST) | |
1239 { | |
1240 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2); | |
1241 if (t && integer_onep (t)) | |
1242 return 2; | |
1243 } | |
1244 | |
1245 return -2; | |
1246 } | |
1247 } | |
1248 | |
1249 /* Compare values like compare_values_warnv, but treat comparisons of | |
1250 nonconstants which rely on undefined overflow as incomparable. */ | |
1251 | |
1252 static int | |
1253 compare_values (tree val1, tree val2) | |
1254 { | |
1255 bool sop; | |
1256 int ret; | |
1257 | |
1258 sop = false; | |
1259 ret = compare_values_warnv (val1, val2, &sop); | |
1260 if (sop | |
1261 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))) | |
1262 ret = -2; | |
1263 return ret; | |
1264 } | |
1265 | |
1266 | |
1267 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX), | |
1268 0 if VAL is not inside VR, | |
1269 -2 if we cannot tell either way. | |
1270 | |
1271 FIXME, the current semantics of this functions are a bit quirky | |
1272 when taken in the context of VRP. In here we do not care | |
1273 about VR's type. If VR is the anti-range ~[3, 5] the call | |
1274 value_inside_range (4, VR) will return 1. | |
1275 | |
1276 This is counter-intuitive in a strict sense, but the callers | |
1277 currently expect this. They are calling the function | |
1278 merely to determine whether VR->MIN <= VAL <= VR->MAX. The | |
1279 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics | |
1280 themselves. | |
1281 | |
1282 This also applies to value_ranges_intersect_p and | |
1283 range_includes_zero_p. The semantics of VR_RANGE and | |
1284 VR_ANTI_RANGE should be encoded here, but that also means | |
1285 adapting the users of these functions to the new semantics. | |
1286 | |
1287 Benchmark compile/20001226-1.c compilation time after changing this | |
1288 function. */ | |
1289 | |
1290 static inline int | |
1291 value_inside_range (tree val, value_range_t * vr) | |
1292 { | |
1293 int cmp1, cmp2; | |
1294 | |
1295 cmp1 = operand_less_p (val, vr->min); | |
1296 if (cmp1 == -2) | |
1297 return -2; | |
1298 if (cmp1 == 1) | |
1299 return 0; | |
1300 | |
1301 cmp2 = operand_less_p (vr->max, val); | |
1302 if (cmp2 == -2) | |
1303 return -2; | |
1304 | |
1305 return !cmp2; | |
1306 } | |
1307 | |
1308 | |
1309 /* Return true if value ranges VR0 and VR1 have a non-empty | |
1310 intersection. | |
1311 | |
1312 Benchmark compile/20001226-1.c compilation time after changing this | |
1313 function. | |
1314 */ | |
1315 | |
1316 static inline bool | |
1317 value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1) | |
1318 { | |
1319 /* The value ranges do not intersect if the maximum of the first range is | |
1320 less than the minimum of the second range or vice versa. | |
1321 When those relations are unknown, we can't do any better. */ | |
1322 if (operand_less_p (vr0->max, vr1->min) != 0) | |
1323 return false; | |
1324 if (operand_less_p (vr1->max, vr0->min) != 0) | |
1325 return false; | |
1326 return true; | |
1327 } | |
1328 | |
1329 | |
1330 /* Return true if VR includes the value zero, false otherwise. FIXME, | |
1331 currently this will return false for an anti-range like ~[-4, 3]. | |
1332 This will be wrong when the semantics of value_inside_range are | |
1333 modified (currently the users of this function expect these | |
1334 semantics). */ | |
1335 | |
1336 static inline bool | |
1337 range_includes_zero_p (value_range_t *vr) | |
1338 { | |
1339 tree zero; | |
1340 | |
1341 gcc_assert (vr->type != VR_UNDEFINED | |
1342 && vr->type != VR_VARYING | |
1343 && !symbolic_range_p (vr)); | |
1344 | |
1345 zero = build_int_cst (TREE_TYPE (vr->min), 0); | |
1346 return (value_inside_range (zero, vr) == 1); | |
1347 } | |
1348 | |
1349 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return | |
1350 false otherwise or if no value range information is available. */ | |
1351 | |
1352 bool | |
1353 ssa_name_nonnegative_p (const_tree t) | |
1354 { | |
1355 value_range_t *vr = get_value_range (t); | |
1356 | |
1357 if (!vr) | |
1358 return false; | |
1359 | |
1360 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range | |
1361 which would return a useful value should be encoded as a VR_RANGE. */ | |
1362 if (vr->type == VR_RANGE) | |
1363 { | |
1364 int result = compare_values (vr->min, integer_zero_node); | |
1365 | |
1366 return (result == 0 || result == 1); | |
1367 } | |
1368 return false; | |
1369 } | |
1370 | |
1371 /* Return true if T, an SSA_NAME, is known to be nonzero. Return | |
1372 false otherwise or if no value range information is available. */ | |
1373 | |
1374 bool | |
1375 ssa_name_nonzero_p (const_tree t) | |
1376 { | |
1377 value_range_t *vr = get_value_range (t); | |
1378 | |
1379 if (!vr) | |
1380 return false; | |
1381 | |
1382 /* A VR_RANGE which does not include zero is a nonzero value. */ | |
1383 if (vr->type == VR_RANGE && !symbolic_range_p (vr)) | |
1384 return ! range_includes_zero_p (vr); | |
1385 | |
1386 /* A VR_ANTI_RANGE which does include zero is a nonzero value. */ | |
1387 if (vr->type == VR_ANTI_RANGE && !symbolic_range_p (vr)) | |
1388 return range_includes_zero_p (vr); | |
1389 | |
1390 return false; | |
1391 } | |
1392 | |
1393 /* If OP has a value range with a single constant value return that, | |
1394 otherwise return NULL_TREE. This returns OP itself if OP is a | |
1395 constant. */ | |
1396 | |
1397 static tree | |
1398 op_with_constant_singleton_value_range (tree op) | |
1399 { | |
1400 value_range_t *vr; | |
1401 | |
1402 if (is_gimple_min_invariant (op)) | |
1403 return op; | |
1404 | |
1405 if (TREE_CODE (op) != SSA_NAME) | |
1406 return NULL_TREE; | |
1407 | |
1408 vr = get_value_range (op); | |
1409 if (vr->type == VR_RANGE | |
1410 && operand_equal_p (vr->min, vr->max, 0) | |
1411 && is_gimple_min_invariant (vr->min)) | |
1412 return vr->min; | |
1413 | |
1414 return NULL_TREE; | |
1415 } | |
1416 | |
1417 | |
1418 /* Extract value range information from an ASSERT_EXPR EXPR and store | |
1419 it in *VR_P. */ | |
1420 | |
1421 static void | |
1422 extract_range_from_assert (value_range_t *vr_p, tree expr) | |
1423 { | |
1424 tree var, cond, limit, min, max, type; | |
1425 value_range_t *var_vr, *limit_vr; | |
1426 enum tree_code cond_code; | |
1427 | |
1428 var = ASSERT_EXPR_VAR (expr); | |
1429 cond = ASSERT_EXPR_COND (expr); | |
1430 | |
1431 gcc_assert (COMPARISON_CLASS_P (cond)); | |
1432 | |
1433 /* Find VAR in the ASSERT_EXPR conditional. */ | |
1434 if (var == TREE_OPERAND (cond, 0) | |
1435 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR | |
1436 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR) | |
1437 { | |
1438 /* If the predicate is of the form VAR COMP LIMIT, then we just | |
1439 take LIMIT from the RHS and use the same comparison code. */ | |
1440 cond_code = TREE_CODE (cond); | |
1441 limit = TREE_OPERAND (cond, 1); | |
1442 cond = TREE_OPERAND (cond, 0); | |
1443 } | |
1444 else | |
1445 { | |
1446 /* If the predicate is of the form LIMIT COMP VAR, then we need | |
1447 to flip around the comparison code to create the proper range | |
1448 for VAR. */ | |
1449 cond_code = swap_tree_comparison (TREE_CODE (cond)); | |
1450 limit = TREE_OPERAND (cond, 0); | |
1451 cond = TREE_OPERAND (cond, 1); | |
1452 } | |
1453 | |
1454 limit = avoid_overflow_infinity (limit); | |
1455 | |
1456 type = TREE_TYPE (limit); | |
1457 gcc_assert (limit != var); | |
1458 | |
1459 /* For pointer arithmetic, we only keep track of pointer equality | |
1460 and inequality. */ | |
1461 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR) | |
1462 { | |
1463 set_value_range_to_varying (vr_p); | |
1464 return; | |
1465 } | |
1466 | |
1467 /* If LIMIT is another SSA name and LIMIT has a range of its own, | |
1468 try to use LIMIT's range to avoid creating symbolic ranges | |
1469 unnecessarily. */ | |
1470 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL; | |
1471 | |
1472 /* LIMIT's range is only interesting if it has any useful information. */ | |
1473 if (limit_vr | |
1474 && (limit_vr->type == VR_UNDEFINED | |
1475 || limit_vr->type == VR_VARYING | |
1476 || symbolic_range_p (limit_vr))) | |
1477 limit_vr = NULL; | |
1478 | |
1479 /* Initially, the new range has the same set of equivalences of | |
1480 VAR's range. This will be revised before returning the final | |
1481 value. Since assertions may be chained via mutually exclusive | |
1482 predicates, we will need to trim the set of equivalences before | |
1483 we are done. */ | |
1484 gcc_assert (vr_p->equiv == NULL); | |
1485 add_equivalence (&vr_p->equiv, var); | |
1486 | |
1487 /* Extract a new range based on the asserted comparison for VAR and | |
1488 LIMIT's value range. Notice that if LIMIT has an anti-range, we | |
1489 will only use it for equality comparisons (EQ_EXPR). For any | |
1490 other kind of assertion, we cannot derive a range from LIMIT's | |
1491 anti-range that can be used to describe the new range. For | |
1492 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10], | |
1493 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is | |
1494 no single range for x_2 that could describe LE_EXPR, so we might | |
1495 as well build the range [b_4, +INF] for it. | |
1496 One special case we handle is extracting a range from a | |
1497 range test encoded as (unsigned)var + CST <= limit. */ | |
1498 if (TREE_CODE (cond) == NOP_EXPR | |
1499 || TREE_CODE (cond) == PLUS_EXPR) | |
1500 { | |
1501 if (TREE_CODE (cond) == PLUS_EXPR) | |
1502 { | |
1503 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)), | |
1504 TREE_OPERAND (cond, 1)); | |
1505 max = int_const_binop (PLUS_EXPR, limit, min, 0); | |
1506 cond = TREE_OPERAND (cond, 0); | |
1507 } | |
1508 else | |
1509 { | |
1510 min = build_int_cst (TREE_TYPE (var), 0); | |
1511 max = limit; | |
1512 } | |
1513 | |
1514 /* Make sure to not set TREE_OVERFLOW on the final type | |
1515 conversion. We are willingly interpreting large positive | |
1516 unsigned values as negative singed values here. */ | |
1517 min = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (min), | |
1518 TREE_INT_CST_HIGH (min), 0, false); | |
1519 max = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (max), | |
1520 TREE_INT_CST_HIGH (max), 0, false); | |
1521 | |
1522 /* We can transform a max, min range to an anti-range or | |
1523 vice-versa. Use set_and_canonicalize_value_range which does | |
1524 this for us. */ | |
1525 if (cond_code == LE_EXPR) | |
1526 set_and_canonicalize_value_range (vr_p, VR_RANGE, | |
1527 min, max, vr_p->equiv); | |
1528 else if (cond_code == GT_EXPR) | |
1529 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE, | |
1530 min, max, vr_p->equiv); | |
1531 else | |
1532 gcc_unreachable (); | |
1533 } | |
1534 else if (cond_code == EQ_EXPR) | |
1535 { | |
1536 enum value_range_type range_type; | |
1537 | |
1538 if (limit_vr) | |
1539 { | |
1540 range_type = limit_vr->type; | |
1541 min = limit_vr->min; | |
1542 max = limit_vr->max; | |
1543 } | |
1544 else | |
1545 { | |
1546 range_type = VR_RANGE; | |
1547 min = limit; | |
1548 max = limit; | |
1549 } | |
1550 | |
1551 set_value_range (vr_p, range_type, min, max, vr_p->equiv); | |
1552 | |
1553 /* When asserting the equality VAR == LIMIT and LIMIT is another | |
1554 SSA name, the new range will also inherit the equivalence set | |
1555 from LIMIT. */ | |
1556 if (TREE_CODE (limit) == SSA_NAME) | |
1557 add_equivalence (&vr_p->equiv, limit); | |
1558 } | |
1559 else if (cond_code == NE_EXPR) | |
1560 { | |
1561 /* As described above, when LIMIT's range is an anti-range and | |
1562 this assertion is an inequality (NE_EXPR), then we cannot | |
1563 derive anything from the anti-range. For instance, if | |
1564 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does | |
1565 not imply that VAR's range is [0, 0]. So, in the case of | |
1566 anti-ranges, we just assert the inequality using LIMIT and | |
1567 not its anti-range. | |
1568 | |
1569 If LIMIT_VR is a range, we can only use it to build a new | |
1570 anti-range if LIMIT_VR is a single-valued range. For | |
1571 instance, if LIMIT_VR is [0, 1], the predicate | |
1572 VAR != [0, 1] does not mean that VAR's range is ~[0, 1]. | |
1573 Rather, it means that for value 0 VAR should be ~[0, 0] | |
1574 and for value 1, VAR should be ~[1, 1]. We cannot | |
1575 represent these ranges. | |
1576 | |
1577 The only situation in which we can build a valid | |
1578 anti-range is when LIMIT_VR is a single-valued range | |
1579 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case, | |
1580 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */ | |
1581 if (limit_vr | |
1582 && limit_vr->type == VR_RANGE | |
1583 && compare_values (limit_vr->min, limit_vr->max) == 0) | |
1584 { | |
1585 min = limit_vr->min; | |
1586 max = limit_vr->max; | |
1587 } | |
1588 else | |
1589 { | |
1590 /* In any other case, we cannot use LIMIT's range to build a | |
1591 valid anti-range. */ | |
1592 min = max = limit; | |
1593 } | |
1594 | |
1595 /* If MIN and MAX cover the whole range for their type, then | |
1596 just use the original LIMIT. */ | |
1597 if (INTEGRAL_TYPE_P (type) | |
1598 && vrp_val_is_min (min) | |
1599 && vrp_val_is_max (max)) | |
1600 min = max = limit; | |
1601 | |
1602 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv); | |
1603 } | |
1604 else if (cond_code == LE_EXPR || cond_code == LT_EXPR) | |
1605 { | |
1606 min = TYPE_MIN_VALUE (type); | |
1607 | |
1608 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE) | |
1609 max = limit; | |
1610 else | |
1611 { | |
1612 /* If LIMIT_VR is of the form [N1, N2], we need to build the | |
1613 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for | |
1614 LT_EXPR. */ | |
1615 max = limit_vr->max; | |
1616 } | |
1617 | |
1618 /* If the maximum value forces us to be out of bounds, simply punt. | |
1619 It would be pointless to try and do anything more since this | |
1620 all should be optimized away above us. */ | |
1621 if ((cond_code == LT_EXPR | |
1622 && compare_values (max, min) == 0) | |
1623 || (CONSTANT_CLASS_P (max) && TREE_OVERFLOW (max))) | |
1624 set_value_range_to_varying (vr_p); | |
1625 else | |
1626 { | |
1627 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */ | |
1628 if (cond_code == LT_EXPR) | |
1629 { | |
1630 tree one = build_int_cst (type, 1); | |
1631 max = fold_build2 (MINUS_EXPR, type, max, one); | |
1632 if (EXPR_P (max)) | |
1633 TREE_NO_WARNING (max) = 1; | |
1634 } | |
1635 | |
1636 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv); | |
1637 } | |
1638 } | |
1639 else if (cond_code == GE_EXPR || cond_code == GT_EXPR) | |
1640 { | |
1641 max = TYPE_MAX_VALUE (type); | |
1642 | |
1643 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE) | |
1644 min = limit; | |
1645 else | |
1646 { | |
1647 /* If LIMIT_VR is of the form [N1, N2], we need to build the | |
1648 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for | |
1649 GT_EXPR. */ | |
1650 min = limit_vr->min; | |
1651 } | |
1652 | |
1653 /* If the minimum value forces us to be out of bounds, simply punt. | |
1654 It would be pointless to try and do anything more since this | |
1655 all should be optimized away above us. */ | |
1656 if ((cond_code == GT_EXPR | |
1657 && compare_values (min, max) == 0) | |
1658 || (CONSTANT_CLASS_P (min) && TREE_OVERFLOW (min))) | |
1659 set_value_range_to_varying (vr_p); | |
1660 else | |
1661 { | |
1662 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */ | |
1663 if (cond_code == GT_EXPR) | |
1664 { | |
1665 tree one = build_int_cst (type, 1); | |
1666 min = fold_build2 (PLUS_EXPR, type, min, one); | |
1667 if (EXPR_P (min)) | |
1668 TREE_NO_WARNING (min) = 1; | |
1669 } | |
1670 | |
1671 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv); | |
1672 } | |
1673 } | |
1674 else | |
1675 gcc_unreachable (); | |
1676 | |
1677 /* If VAR already had a known range, it may happen that the new | |
1678 range we have computed and VAR's range are not compatible. For | |
1679 instance, | |
1680 | |
1681 if (p_5 == NULL) | |
1682 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>; | |
1683 x_7 = p_6->fld; | |
1684 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>; | |
1685 | |
1686 While the above comes from a faulty program, it will cause an ICE | |
1687 later because p_8 and p_6 will have incompatible ranges and at | |
1688 the same time will be considered equivalent. A similar situation | |
1689 would arise from | |
1690 | |
1691 if (i_5 > 10) | |
1692 i_6 = ASSERT_EXPR <i_5, i_5 > 10>; | |
1693 if (i_5 < 5) | |
1694 i_7 = ASSERT_EXPR <i_6, i_6 < 5>; | |
1695 | |
1696 Again i_6 and i_7 will have incompatible ranges. It would be | |
1697 pointless to try and do anything with i_7's range because | |
1698 anything dominated by 'if (i_5 < 5)' will be optimized away. | |
1699 Note, due to the wa in which simulation proceeds, the statement | |
1700 i_7 = ASSERT_EXPR <...> we would never be visited because the | |
1701 conditional 'if (i_5 < 5)' always evaluates to false. However, | |
1702 this extra check does not hurt and may protect against future | |
1703 changes to VRP that may get into a situation similar to the | |
1704 NULL pointer dereference example. | |
1705 | |
1706 Note that these compatibility tests are only needed when dealing | |
1707 with ranges or a mix of range and anti-range. If VAR_VR and VR_P | |
1708 are both anti-ranges, they will always be compatible, because two | |
1709 anti-ranges will always have a non-empty intersection. */ | |
1710 | |
1711 var_vr = get_value_range (var); | |
1712 | |
1713 /* We may need to make adjustments when VR_P and VAR_VR are numeric | |
1714 ranges or anti-ranges. */ | |
1715 if (vr_p->type == VR_VARYING | |
1716 || vr_p->type == VR_UNDEFINED | |
1717 || var_vr->type == VR_VARYING | |
1718 || var_vr->type == VR_UNDEFINED | |
1719 || symbolic_range_p (vr_p) | |
1720 || symbolic_range_p (var_vr)) | |
1721 return; | |
1722 | |
1723 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE) | |
1724 { | |
1725 /* If the two ranges have a non-empty intersection, we can | |
1726 refine the resulting range. Since the assert expression | |
1727 creates an equivalency and at the same time it asserts a | |
1728 predicate, we can take the intersection of the two ranges to | |
1729 get better precision. */ | |
1730 if (value_ranges_intersect_p (var_vr, vr_p)) | |
1731 { | |
1732 /* Use the larger of the two minimums. */ | |
1733 if (compare_values (vr_p->min, var_vr->min) == -1) | |
1734 min = var_vr->min; | |
1735 else | |
1736 min = vr_p->min; | |
1737 | |
1738 /* Use the smaller of the two maximums. */ | |
1739 if (compare_values (vr_p->max, var_vr->max) == 1) | |
1740 max = var_vr->max; | |
1741 else | |
1742 max = vr_p->max; | |
1743 | |
1744 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv); | |
1745 } | |
1746 else | |
1747 { | |
1748 /* The two ranges do not intersect, set the new range to | |
1749 VARYING, because we will not be able to do anything | |
1750 meaningful with it. */ | |
1751 set_value_range_to_varying (vr_p); | |
1752 } | |
1753 } | |
1754 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE) | |
1755 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE)) | |
1756 { | |
1757 /* A range and an anti-range will cancel each other only if | |
1758 their ends are the same. For instance, in the example above, | |
1759 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible, | |
1760 so VR_P should be set to VR_VARYING. */ | |
1761 if (compare_values (var_vr->min, vr_p->min) == 0 | |
1762 && compare_values (var_vr->max, vr_p->max) == 0) | |
1763 set_value_range_to_varying (vr_p); | |
1764 else | |
1765 { | |
1766 tree min, max, anti_min, anti_max, real_min, real_max; | |
1767 int cmp; | |
1768 | |
1769 /* We want to compute the logical AND of the two ranges; | |
1770 there are three cases to consider. | |
1771 | |
1772 | |
1773 1. The VR_ANTI_RANGE range is completely within the | |
1774 VR_RANGE and the endpoints of the ranges are | |
1775 different. In that case the resulting range | |
1776 should be whichever range is more precise. | |
1777 Typically that will be the VR_RANGE. | |
1778 | |
1779 2. The VR_ANTI_RANGE is completely disjoint from | |
1780 the VR_RANGE. In this case the resulting range | |
1781 should be the VR_RANGE. | |
1782 | |
1783 3. There is some overlap between the VR_ANTI_RANGE | |
1784 and the VR_RANGE. | |
1785 | |
1786 3a. If the high limit of the VR_ANTI_RANGE resides | |
1787 within the VR_RANGE, then the result is a new | |
1788 VR_RANGE starting at the high limit of the | |
1789 VR_ANTI_RANGE + 1 and extending to the | |
1790 high limit of the original VR_RANGE. | |
1791 | |
1792 3b. If the low limit of the VR_ANTI_RANGE resides | |
1793 within the VR_RANGE, then the result is a new | |
1794 VR_RANGE starting at the low limit of the original | |
1795 VR_RANGE and extending to the low limit of the | |
1796 VR_ANTI_RANGE - 1. */ | |
1797 if (vr_p->type == VR_ANTI_RANGE) | |
1798 { | |
1799 anti_min = vr_p->min; | |
1800 anti_max = vr_p->max; | |
1801 real_min = var_vr->min; | |
1802 real_max = var_vr->max; | |
1803 } | |
1804 else | |
1805 { | |
1806 anti_min = var_vr->min; | |
1807 anti_max = var_vr->max; | |
1808 real_min = vr_p->min; | |
1809 real_max = vr_p->max; | |
1810 } | |
1811 | |
1812 | |
1813 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE, | |
1814 not including any endpoints. */ | |
1815 if (compare_values (anti_max, real_max) == -1 | |
1816 && compare_values (anti_min, real_min) == 1) | |
1817 { | |
1818 /* If the range is covering the whole valid range of | |
1819 the type keep the anti-range. */ | |
1820 if (!vrp_val_is_min (real_min) | |
1821 || !vrp_val_is_max (real_max)) | |
1822 set_value_range (vr_p, VR_RANGE, real_min, | |
1823 real_max, vr_p->equiv); | |
1824 } | |
1825 /* Case 2, VR_ANTI_RANGE completely disjoint from | |
1826 VR_RANGE. */ | |
1827 else if (compare_values (anti_min, real_max) == 1 | |
1828 || compare_values (anti_max, real_min) == -1) | |
1829 { | |
1830 set_value_range (vr_p, VR_RANGE, real_min, | |
1831 real_max, vr_p->equiv); | |
1832 } | |
1833 /* Case 3a, the anti-range extends into the low | |
1834 part of the real range. Thus creating a new | |
1835 low for the real range. */ | |
1836 else if (((cmp = compare_values (anti_max, real_min)) == 1 | |
1837 || cmp == 0) | |
1838 && compare_values (anti_max, real_max) == -1) | |
1839 { | |
1840 gcc_assert (!is_positive_overflow_infinity (anti_max)); | |
1841 if (needs_overflow_infinity (TREE_TYPE (anti_max)) | |
1842 && vrp_val_is_max (anti_max)) | |
1843 { | |
1844 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min))) | |
1845 { | |
1846 set_value_range_to_varying (vr_p); | |
1847 return; | |
1848 } | |
1849 min = positive_overflow_infinity (TREE_TYPE (var_vr->min)); | |
1850 } | |
1851 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min))) | |
1852 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min), | |
1853 anti_max, | |
1854 build_int_cst (TREE_TYPE (var_vr->min), 1)); | |
1855 else | |
1856 min = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min), | |
1857 anti_max, size_int (1)); | |
1858 max = real_max; | |
1859 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv); | |
1860 } | |
1861 /* Case 3b, the anti-range extends into the high | |
1862 part of the real range. Thus creating a new | |
1863 higher for the real range. */ | |
1864 else if (compare_values (anti_min, real_min) == 1 | |
1865 && ((cmp = compare_values (anti_min, real_max)) == -1 | |
1866 || cmp == 0)) | |
1867 { | |
1868 gcc_assert (!is_negative_overflow_infinity (anti_min)); | |
1869 if (needs_overflow_infinity (TREE_TYPE (anti_min)) | |
1870 && vrp_val_is_min (anti_min)) | |
1871 { | |
1872 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min))) | |
1873 { | |
1874 set_value_range_to_varying (vr_p); | |
1875 return; | |
1876 } | |
1877 max = negative_overflow_infinity (TREE_TYPE (var_vr->min)); | |
1878 } | |
1879 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min))) | |
1880 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min), | |
1881 anti_min, | |
1882 build_int_cst (TREE_TYPE (var_vr->min), 1)); | |
1883 else | |
1884 max = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min), | |
1885 anti_min, | |
1886 size_int (-1)); | |
1887 min = real_min; | |
1888 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv); | |
1889 } | |
1890 } | |
1891 } | |
1892 } | |
1893 | |
1894 | |
1895 /* Extract range information from SSA name VAR and store it in VR. If | |
1896 VAR has an interesting range, use it. Otherwise, create the | |
1897 range [VAR, VAR] and return it. This is useful in situations where | |
1898 we may have conditionals testing values of VARYING names. For | |
1899 instance, | |
1900 | |
1901 x_3 = y_5; | |
1902 if (x_3 > y_5) | |
1903 ... | |
1904 | |
1905 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is | |
1906 always false. */ | |
1907 | |
1908 static void | |
1909 extract_range_from_ssa_name (value_range_t *vr, tree var) | |
1910 { | |
1911 value_range_t *var_vr = get_value_range (var); | |
1912 | |
1913 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING) | |
1914 copy_value_range (vr, var_vr); | |
1915 else | |
1916 set_value_range (vr, VR_RANGE, var, var, NULL); | |
1917 | |
1918 add_equivalence (&vr->equiv, var); | |
1919 } | |
1920 | |
1921 | |
1922 /* Wrapper around int_const_binop. If the operation overflows and we | |
1923 are not using wrapping arithmetic, then adjust the result to be | |
1924 -INF or +INF depending on CODE, VAL1 and VAL2. This can return | |
1925 NULL_TREE if we need to use an overflow infinity representation but | |
1926 the type does not support it. */ | |
1927 | |
1928 static tree | |
1929 vrp_int_const_binop (enum tree_code code, tree val1, tree val2) | |
1930 { | |
1931 tree res; | |
1932 | |
1933 res = int_const_binop (code, val1, val2, 0); | |
1934 | |
1935 /* If we are not using wrapping arithmetic, operate symbolically | |
1936 on -INF and +INF. */ | |
1937 if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1))) | |
1938 { | |
1939 int checkz = compare_values (res, val1); | |
1940 bool overflow = false; | |
1941 | |
1942 /* Ensure that res = val1 [+*] val2 >= val1 | |
1943 or that res = val1 - val2 <= val1. */ | |
1944 if ((code == PLUS_EXPR | |
1945 && !(checkz == 1 || checkz == 0)) | |
1946 || (code == MINUS_EXPR | |
1947 && !(checkz == 0 || checkz == -1))) | |
1948 { | |
1949 overflow = true; | |
1950 } | |
1951 /* Checking for multiplication overflow is done by dividing the | |
1952 output of the multiplication by the first input of the | |
1953 multiplication. If the result of that division operation is | |
1954 not equal to the second input of the multiplication, then the | |
1955 multiplication overflowed. */ | |
1956 else if (code == MULT_EXPR && !integer_zerop (val1)) | |
1957 { | |
1958 tree tmp = int_const_binop (TRUNC_DIV_EXPR, | |
1959 res, | |
1960 val1, 0); | |
1961 int check = compare_values (tmp, val2); | |
1962 | |
1963 if (check != 0) | |
1964 overflow = true; | |
1965 } | |
1966 | |
1967 if (overflow) | |
1968 { | |
1969 res = copy_node (res); | |
1970 TREE_OVERFLOW (res) = 1; | |
1971 } | |
1972 | |
1973 } | |
1974 else if ((TREE_OVERFLOW (res) | |
1975 && !TREE_OVERFLOW (val1) | |
1976 && !TREE_OVERFLOW (val2)) | |
1977 || is_overflow_infinity (val1) | |
1978 || is_overflow_infinity (val2)) | |
1979 { | |
1980 /* If the operation overflowed but neither VAL1 nor VAL2 are | |
1981 overflown, return -INF or +INF depending on the operation | |
1982 and the combination of signs of the operands. */ | |
1983 int sgn1 = tree_int_cst_sgn (val1); | |
1984 int sgn2 = tree_int_cst_sgn (val2); | |
1985 | |
1986 if (needs_overflow_infinity (TREE_TYPE (res)) | |
1987 && !supports_overflow_infinity (TREE_TYPE (res))) | |
1988 return NULL_TREE; | |
1989 | |
1990 /* We have to punt on adding infinities of different signs, | |
1991 since we can't tell what the sign of the result should be. | |
1992 Likewise for subtracting infinities of the same sign. */ | |
1993 if (((code == PLUS_EXPR && sgn1 != sgn2) | |
1994 || (code == MINUS_EXPR && sgn1 == sgn2)) | |
1995 && is_overflow_infinity (val1) | |
1996 && is_overflow_infinity (val2)) | |
1997 return NULL_TREE; | |
1998 | |
1999 /* Don't try to handle division or shifting of infinities. */ | |
2000 if ((code == TRUNC_DIV_EXPR | |
2001 || code == FLOOR_DIV_EXPR | |
2002 || code == CEIL_DIV_EXPR | |
2003 || code == EXACT_DIV_EXPR | |
2004 || code == ROUND_DIV_EXPR | |
2005 || code == RSHIFT_EXPR) | |
2006 && (is_overflow_infinity (val1) | |
2007 || is_overflow_infinity (val2))) | |
2008 return NULL_TREE; | |
2009 | |
2010 /* Notice that we only need to handle the restricted set of | |
2011 operations handled by extract_range_from_binary_expr. | |
2012 Among them, only multiplication, addition and subtraction | |
2013 can yield overflow without overflown operands because we | |
2014 are working with integral types only... except in the | |
2015 case VAL1 = -INF and VAL2 = -1 which overflows to +INF | |
2016 for division too. */ | |
2017 | |
2018 /* For multiplication, the sign of the overflow is given | |
2019 by the comparison of the signs of the operands. */ | |
2020 if ((code == MULT_EXPR && sgn1 == sgn2) | |
2021 /* For addition, the operands must be of the same sign | |
2022 to yield an overflow. Its sign is therefore that | |
2023 of one of the operands, for example the first. For | |
2024 infinite operands X + -INF is negative, not positive. */ | |
2025 || (code == PLUS_EXPR | |
2026 && (sgn1 >= 0 | |
2027 ? !is_negative_overflow_infinity (val2) | |
2028 : is_positive_overflow_infinity (val2))) | |
2029 /* For subtraction, non-infinite operands must be of | |
2030 different signs to yield an overflow. Its sign is | |
2031 therefore that of the first operand or the opposite of | |
2032 that of the second operand. A first operand of 0 counts | |
2033 as positive here, for the corner case 0 - (-INF), which | |
2034 overflows, but must yield +INF. For infinite operands 0 | |
2035 - INF is negative, not positive. */ | |
2036 || (code == MINUS_EXPR | |
2037 && (sgn1 >= 0 | |
2038 ? !is_positive_overflow_infinity (val2) | |
2039 : is_negative_overflow_infinity (val2))) | |
2040 /* We only get in here with positive shift count, so the | |
2041 overflow direction is the same as the sign of val1. | |
2042 Actually rshift does not overflow at all, but we only | |
2043 handle the case of shifting overflowed -INF and +INF. */ | |
2044 || (code == RSHIFT_EXPR | |
2045 && sgn1 >= 0) | |
2046 /* For division, the only case is -INF / -1 = +INF. */ | |
2047 || code == TRUNC_DIV_EXPR | |
2048 || code == FLOOR_DIV_EXPR | |
2049 || code == CEIL_DIV_EXPR | |
2050 || code == EXACT_DIV_EXPR | |
2051 || code == ROUND_DIV_EXPR) | |
2052 return (needs_overflow_infinity (TREE_TYPE (res)) | |
2053 ? positive_overflow_infinity (TREE_TYPE (res)) | |
2054 : TYPE_MAX_VALUE (TREE_TYPE (res))); | |
2055 else | |
2056 return (needs_overflow_infinity (TREE_TYPE (res)) | |
2057 ? negative_overflow_infinity (TREE_TYPE (res)) | |
2058 : TYPE_MIN_VALUE (TREE_TYPE (res))); | |
2059 } | |
2060 | |
2061 return res; | |
2062 } | |
2063 | |
2064 | |
2065 /* Extract range information from a binary expression EXPR based on | |
2066 the ranges of each of its operands and the expression code. */ | |
2067 | |
2068 static void | |
2069 extract_range_from_binary_expr (value_range_t *vr, | |
2070 enum tree_code code, | |
2071 tree expr_type, tree op0, tree op1) | |
2072 { | |
2073 enum value_range_type type; | |
2074 tree min, max; | |
2075 int cmp; | |
2076 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL }; | |
2077 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL }; | |
2078 | |
2079 /* Not all binary expressions can be applied to ranges in a | |
2080 meaningful way. Handle only arithmetic operations. */ | |
2081 if (code != PLUS_EXPR | |
2082 && code != MINUS_EXPR | |
2083 && code != POINTER_PLUS_EXPR | |
2084 && code != MULT_EXPR | |
2085 && code != TRUNC_DIV_EXPR | |
2086 && code != FLOOR_DIV_EXPR | |
2087 && code != CEIL_DIV_EXPR | |
2088 && code != EXACT_DIV_EXPR | |
2089 && code != ROUND_DIV_EXPR | |
2090 && code != RSHIFT_EXPR | |
2091 && code != MIN_EXPR | |
2092 && code != MAX_EXPR | |
2093 && code != BIT_AND_EXPR | |
2094 && code != BIT_IOR_EXPR | |
2095 && code != TRUTH_AND_EXPR | |
2096 && code != TRUTH_OR_EXPR) | |
2097 { | |
2098 /* We can still do constant propagation here. */ | |
2099 tree const_op0 = op_with_constant_singleton_value_range (op0); | |
2100 tree const_op1 = op_with_constant_singleton_value_range (op1); | |
2101 if (const_op0 || const_op1) | |
2102 { | |
2103 tree tem = fold_binary (code, expr_type, | |
2104 const_op0 ? const_op0 : op0, | |
2105 const_op1 ? const_op1 : op1); | |
2106 if (tem | |
2107 && is_gimple_min_invariant (tem) | |
2108 && !is_overflow_infinity (tem)) | |
2109 { | |
2110 set_value_range (vr, VR_RANGE, tem, tem, NULL); | |
2111 return; | |
2112 } | |
2113 } | |
2114 set_value_range_to_varying (vr); | |
2115 return; | |
2116 } | |
2117 | |
2118 /* Get value ranges for each operand. For constant operands, create | |
2119 a new value range with the operand to simplify processing. */ | |
2120 if (TREE_CODE (op0) == SSA_NAME) | |
2121 vr0 = *(get_value_range (op0)); | |
2122 else if (is_gimple_min_invariant (op0)) | |
2123 set_value_range_to_value (&vr0, op0, NULL); | |
2124 else | |
2125 set_value_range_to_varying (&vr0); | |
2126 | |
2127 if (TREE_CODE (op1) == SSA_NAME) | |
2128 vr1 = *(get_value_range (op1)); | |
2129 else if (is_gimple_min_invariant (op1)) | |
2130 set_value_range_to_value (&vr1, op1, NULL); | |
2131 else | |
2132 set_value_range_to_varying (&vr1); | |
2133 | |
2134 /* If either range is UNDEFINED, so is the result. */ | |
2135 if (vr0.type == VR_UNDEFINED || vr1.type == VR_UNDEFINED) | |
2136 { | |
2137 set_value_range_to_undefined (vr); | |
2138 return; | |
2139 } | |
2140 | |
2141 /* The type of the resulting value range defaults to VR0.TYPE. */ | |
2142 type = vr0.type; | |
2143 | |
2144 /* Refuse to operate on VARYING ranges, ranges of different kinds | |
2145 and symbolic ranges. As an exception, we allow BIT_AND_EXPR | |
2146 because we may be able to derive a useful range even if one of | |
2147 the operands is VR_VARYING or symbolic range. Similarly for | |
2148 divisions. TODO, we may be able to derive anti-ranges in | |
2149 some cases. */ | |
2150 if (code != BIT_AND_EXPR | |
2151 && code != TRUTH_AND_EXPR | |
2152 && code != TRUTH_OR_EXPR | |
2153 && code != TRUNC_DIV_EXPR | |
2154 && code != FLOOR_DIV_EXPR | |
2155 && code != CEIL_DIV_EXPR | |
2156 && code != EXACT_DIV_EXPR | |
2157 && code != ROUND_DIV_EXPR | |
2158 && (vr0.type == VR_VARYING | |
2159 || vr1.type == VR_VARYING | |
2160 || vr0.type != vr1.type | |
2161 || symbolic_range_p (&vr0) | |
2162 || symbolic_range_p (&vr1))) | |
2163 { | |
2164 set_value_range_to_varying (vr); | |
2165 return; | |
2166 } | |
2167 | |
2168 /* Now evaluate the expression to determine the new range. */ | |
2169 if (POINTER_TYPE_P (expr_type) | |
2170 || POINTER_TYPE_P (TREE_TYPE (op0)) | |
2171 || POINTER_TYPE_P (TREE_TYPE (op1))) | |
2172 { | |
2173 if (code == MIN_EXPR || code == MAX_EXPR) | |
2174 { | |
2175 /* For MIN/MAX expressions with pointers, we only care about | |
2176 nullness, if both are non null, then the result is nonnull. | |
2177 If both are null, then the result is null. Otherwise they | |
2178 are varying. */ | |
2179 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1)) | |
2180 set_value_range_to_nonnull (vr, expr_type); | |
2181 else if (range_is_null (&vr0) && range_is_null (&vr1)) | |
2182 set_value_range_to_null (vr, expr_type); | |
2183 else | |
2184 set_value_range_to_varying (vr); | |
2185 | |
2186 return; | |
2187 } | |
2188 gcc_assert (code == POINTER_PLUS_EXPR); | |
2189 /* For pointer types, we are really only interested in asserting | |
2190 whether the expression evaluates to non-NULL. */ | |
2191 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1)) | |
2192 set_value_range_to_nonnull (vr, expr_type); | |
2193 else if (range_is_null (&vr0) && range_is_null (&vr1)) | |
2194 set_value_range_to_null (vr, expr_type); | |
2195 else | |
2196 set_value_range_to_varying (vr); | |
2197 | |
2198 return; | |
2199 } | |
2200 | |
2201 /* For integer ranges, apply the operation to each end of the | |
2202 range and see what we end up with. */ | |
2203 if (code == TRUTH_AND_EXPR | |
2204 || code == TRUTH_OR_EXPR) | |
2205 { | |
2206 /* If one of the operands is zero, we know that the whole | |
2207 expression evaluates zero. */ | |
2208 if (code == TRUTH_AND_EXPR | |
2209 && ((vr0.type == VR_RANGE | |
2210 && integer_zerop (vr0.min) | |
2211 && integer_zerop (vr0.max)) | |
2212 || (vr1.type == VR_RANGE | |
2213 && integer_zerop (vr1.min) | |
2214 && integer_zerop (vr1.max)))) | |
2215 { | |
2216 type = VR_RANGE; | |
2217 min = max = build_int_cst (expr_type, 0); | |
2218 } | |
2219 /* If one of the operands is one, we know that the whole | |
2220 expression evaluates one. */ | |
2221 else if (code == TRUTH_OR_EXPR | |
2222 && ((vr0.type == VR_RANGE | |
2223 && integer_onep (vr0.min) | |
2224 && integer_onep (vr0.max)) | |
2225 || (vr1.type == VR_RANGE | |
2226 && integer_onep (vr1.min) | |
2227 && integer_onep (vr1.max)))) | |
2228 { | |
2229 type = VR_RANGE; | |
2230 min = max = build_int_cst (expr_type, 1); | |
2231 } | |
2232 else if (vr0.type != VR_VARYING | |
2233 && vr1.type != VR_VARYING | |
2234 && vr0.type == vr1.type | |
2235 && !symbolic_range_p (&vr0) | |
2236 && !overflow_infinity_range_p (&vr0) | |
2237 && !symbolic_range_p (&vr1) | |
2238 && !overflow_infinity_range_p (&vr1)) | |
2239 { | |
2240 /* Boolean expressions cannot be folded with int_const_binop. */ | |
2241 min = fold_binary (code, expr_type, vr0.min, vr1.min); | |
2242 max = fold_binary (code, expr_type, vr0.max, vr1.max); | |
2243 } | |
2244 else | |
2245 { | |
2246 /* The result of a TRUTH_*_EXPR is always true or false. */ | |
2247 set_value_range_to_truthvalue (vr, expr_type); | |
2248 return; | |
2249 } | |
2250 } | |
2251 else if (code == PLUS_EXPR | |
2252 || code == MIN_EXPR | |
2253 || code == MAX_EXPR) | |
2254 { | |
2255 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to | |
2256 VR_VARYING. It would take more effort to compute a precise | |
2257 range for such a case. For example, if we have op0 == 1 and | |
2258 op1 == -1 with their ranges both being ~[0,0], we would have | |
2259 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0]. | |
2260 Note that we are guaranteed to have vr0.type == vr1.type at | |
2261 this point. */ | |
2262 if (code == PLUS_EXPR && vr0.type == VR_ANTI_RANGE) | |
2263 { | |
2264 set_value_range_to_varying (vr); | |
2265 return; | |
2266 } | |
2267 | |
2268 /* For operations that make the resulting range directly | |
2269 proportional to the original ranges, apply the operation to | |
2270 the same end of each range. */ | |
2271 min = vrp_int_const_binop (code, vr0.min, vr1.min); | |
2272 max = vrp_int_const_binop (code, vr0.max, vr1.max); | |
2273 } | |
2274 else if (code == MULT_EXPR | |
2275 || code == TRUNC_DIV_EXPR | |
2276 || code == FLOOR_DIV_EXPR | |
2277 || code == CEIL_DIV_EXPR | |
2278 || code == EXACT_DIV_EXPR | |
2279 || code == ROUND_DIV_EXPR | |
2280 || code == RSHIFT_EXPR) | |
2281 { | |
2282 tree val[4]; | |
2283 size_t i; | |
2284 bool sop; | |
2285 | |
2286 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs, | |
2287 drop to VR_VARYING. It would take more effort to compute a | |
2288 precise range for such a case. For example, if we have | |
2289 op0 == 65536 and op1 == 65536 with their ranges both being | |
2290 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so | |
2291 we cannot claim that the product is in ~[0,0]. Note that we | |
2292 are guaranteed to have vr0.type == vr1.type at this | |
2293 point. */ | |
2294 if (code == MULT_EXPR | |
2295 && vr0.type == VR_ANTI_RANGE | |
2296 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0))) | |
2297 { | |
2298 set_value_range_to_varying (vr); | |
2299 return; | |
2300 } | |
2301 | |
2302 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1], | |
2303 then drop to VR_VARYING. Outside of this range we get undefined | |
2304 behavior from the shift operation. We cannot even trust | |
2305 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl | |
2306 shifts, and the operation at the tree level may be widened. */ | |
2307 if (code == RSHIFT_EXPR) | |
2308 { | |
2309 if (vr1.type == VR_ANTI_RANGE | |
2310 || !vrp_expr_computes_nonnegative (op1, &sop) | |
2311 || (operand_less_p | |
2312 (build_int_cst (TREE_TYPE (vr1.max), | |
2313 TYPE_PRECISION (expr_type) - 1), | |
2314 vr1.max) != 0)) | |
2315 { | |
2316 set_value_range_to_varying (vr); | |
2317 return; | |
2318 } | |
2319 } | |
2320 | |
2321 else if ((code == TRUNC_DIV_EXPR | |
2322 || code == FLOOR_DIV_EXPR | |
2323 || code == CEIL_DIV_EXPR | |
2324 || code == EXACT_DIV_EXPR | |
2325 || code == ROUND_DIV_EXPR) | |
2326 && (vr0.type != VR_RANGE || symbolic_range_p (&vr0))) | |
2327 { | |
2328 /* For division, if op1 has VR_RANGE but op0 does not, something | |
2329 can be deduced just from that range. Say [min, max] / [4, max] | |
2330 gives [min / 4, max / 4] range. */ | |
2331 if (vr1.type == VR_RANGE | |
2332 && !symbolic_range_p (&vr1) | |
2333 && !range_includes_zero_p (&vr1)) | |
2334 { | |
2335 vr0.type = type = VR_RANGE; | |
2336 vr0.min = vrp_val_min (TREE_TYPE (op0)); | |
2337 vr0.max = vrp_val_max (TREE_TYPE (op1)); | |
2338 } | |
2339 else | |
2340 { | |
2341 set_value_range_to_varying (vr); | |
2342 return; | |
2343 } | |
2344 } | |
2345 | |
2346 /* For divisions, if op0 is VR_RANGE, we can deduce a range | |
2347 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can | |
2348 include 0. */ | |
2349 if ((code == TRUNC_DIV_EXPR | |
2350 || code == FLOOR_DIV_EXPR | |
2351 || code == CEIL_DIV_EXPR | |
2352 || code == EXACT_DIV_EXPR | |
2353 || code == ROUND_DIV_EXPR) | |
2354 && vr0.type == VR_RANGE | |
2355 && (vr1.type != VR_RANGE | |
2356 || symbolic_range_p (&vr1) | |
2357 || range_includes_zero_p (&vr1))) | |
2358 { | |
2359 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0); | |
2360 int cmp; | |
2361 | |
2362 sop = false; | |
2363 min = NULL_TREE; | |
2364 max = NULL_TREE; | |
2365 if (vrp_expr_computes_nonnegative (op1, &sop) && !sop) | |
2366 { | |
2367 /* For unsigned division or when divisor is known | |
2368 to be non-negative, the range has to cover | |
2369 all numbers from 0 to max for positive max | |
2370 and all numbers from min to 0 for negative min. */ | |
2371 cmp = compare_values (vr0.max, zero); | |
2372 if (cmp == -1) | |
2373 max = zero; | |
2374 else if (cmp == 0 || cmp == 1) | |
2375 max = vr0.max; | |
2376 else | |
2377 type = VR_VARYING; | |
2378 cmp = compare_values (vr0.min, zero); | |
2379 if (cmp == 1) | |
2380 min = zero; | |
2381 else if (cmp == 0 || cmp == -1) | |
2382 min = vr0.min; | |
2383 else | |
2384 type = VR_VARYING; | |
2385 } | |
2386 else | |
2387 { | |
2388 /* Otherwise the range is -max .. max or min .. -min | |
2389 depending on which bound is bigger in absolute value, | |
2390 as the division can change the sign. */ | |
2391 abs_extent_range (vr, vr0.min, vr0.max); | |
2392 return; | |
2393 } | |
2394 if (type == VR_VARYING) | |
2395 { | |
2396 set_value_range_to_varying (vr); | |
2397 return; | |
2398 } | |
2399 } | |
2400 | |
2401 /* Multiplications and divisions are a bit tricky to handle, | |
2402 depending on the mix of signs we have in the two ranges, we | |
2403 need to operate on different values to get the minimum and | |
2404 maximum values for the new range. One approach is to figure | |
2405 out all the variations of range combinations and do the | |
2406 operations. | |
2407 | |
2408 However, this involves several calls to compare_values and it | |
2409 is pretty convoluted. It's simpler to do the 4 operations | |
2410 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP | |
2411 MAX1) and then figure the smallest and largest values to form | |
2412 the new range. */ | |
2413 else | |
2414 { | |
2415 gcc_assert ((vr0.type == VR_RANGE | |
2416 || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE)) | |
2417 && vr0.type == vr1.type); | |
2418 | |
2419 /* Compute the 4 cross operations. */ | |
2420 sop = false; | |
2421 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min); | |
2422 if (val[0] == NULL_TREE) | |
2423 sop = true; | |
2424 | |
2425 if (vr1.max == vr1.min) | |
2426 val[1] = NULL_TREE; | |
2427 else | |
2428 { | |
2429 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max); | |
2430 if (val[1] == NULL_TREE) | |
2431 sop = true; | |
2432 } | |
2433 | |
2434 if (vr0.max == vr0.min) | |
2435 val[2] = NULL_TREE; | |
2436 else | |
2437 { | |
2438 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min); | |
2439 if (val[2] == NULL_TREE) | |
2440 sop = true; | |
2441 } | |
2442 | |
2443 if (vr0.min == vr0.max || vr1.min == vr1.max) | |
2444 val[3] = NULL_TREE; | |
2445 else | |
2446 { | |
2447 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max); | |
2448 if (val[3] == NULL_TREE) | |
2449 sop = true; | |
2450 } | |
2451 | |
2452 if (sop) | |
2453 { | |
2454 set_value_range_to_varying (vr); | |
2455 return; | |
2456 } | |
2457 | |
2458 /* Set MIN to the minimum of VAL[i] and MAX to the maximum | |
2459 of VAL[i]. */ | |
2460 min = val[0]; | |
2461 max = val[0]; | |
2462 for (i = 1; i < 4; i++) | |
2463 { | |
2464 if (!is_gimple_min_invariant (min) | |
2465 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min)) | |
2466 || !is_gimple_min_invariant (max) | |
2467 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max))) | |
2468 break; | |
2469 | |
2470 if (val[i]) | |
2471 { | |
2472 if (!is_gimple_min_invariant (val[i]) | |
2473 || (TREE_OVERFLOW (val[i]) | |
2474 && !is_overflow_infinity (val[i]))) | |
2475 { | |
2476 /* If we found an overflowed value, set MIN and MAX | |
2477 to it so that we set the resulting range to | |
2478 VARYING. */ | |
2479 min = max = val[i]; | |
2480 break; | |
2481 } | |
2482 | |
2483 if (compare_values (val[i], min) == -1) | |
2484 min = val[i]; | |
2485 | |
2486 if (compare_values (val[i], max) == 1) | |
2487 max = val[i]; | |
2488 } | |
2489 } | |
2490 } | |
2491 } | |
2492 else if (code == MINUS_EXPR) | |
2493 { | |
2494 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to | |
2495 VR_VARYING. It would take more effort to compute a precise | |
2496 range for such a case. For example, if we have op0 == 1 and | |
2497 op1 == 1 with their ranges both being ~[0,0], we would have | |
2498 op0 - op1 == 0, so we cannot claim that the difference is in | |
2499 ~[0,0]. Note that we are guaranteed to have | |
2500 vr0.type == vr1.type at this point. */ | |
2501 if (vr0.type == VR_ANTI_RANGE) | |
2502 { | |
2503 set_value_range_to_varying (vr); | |
2504 return; | |
2505 } | |
2506 | |
2507 /* For MINUS_EXPR, apply the operation to the opposite ends of | |
2508 each range. */ | |
2509 min = vrp_int_const_binop (code, vr0.min, vr1.max); | |
2510 max = vrp_int_const_binop (code, vr0.max, vr1.min); | |
2511 } | |
2512 else if (code == BIT_AND_EXPR) | |
2513 { | |
2514 if (vr0.type == VR_RANGE | |
2515 && vr0.min == vr0.max | |
2516 && TREE_CODE (vr0.max) == INTEGER_CST | |
2517 && !TREE_OVERFLOW (vr0.max) | |
2518 && tree_int_cst_sgn (vr0.max) >= 0) | |
2519 { | |
2520 min = build_int_cst (expr_type, 0); | |
2521 max = vr0.max; | |
2522 } | |
2523 else if (vr1.type == VR_RANGE | |
2524 && vr1.min == vr1.max | |
2525 && TREE_CODE (vr1.max) == INTEGER_CST | |
2526 && !TREE_OVERFLOW (vr1.max) | |
2527 && tree_int_cst_sgn (vr1.max) >= 0) | |
2528 { | |
2529 type = VR_RANGE; | |
2530 min = build_int_cst (expr_type, 0); | |
2531 max = vr1.max; | |
2532 } | |
2533 else | |
2534 { | |
2535 set_value_range_to_varying (vr); | |
2536 return; | |
2537 } | |
2538 } | |
2539 else if (code == BIT_IOR_EXPR) | |
2540 { | |
2541 if (vr0.type == VR_RANGE | |
2542 && vr1.type == VR_RANGE | |
2543 && TREE_CODE (vr0.min) == INTEGER_CST | |
2544 && TREE_CODE (vr1.min) == INTEGER_CST | |
2545 && TREE_CODE (vr0.max) == INTEGER_CST | |
2546 && TREE_CODE (vr1.max) == INTEGER_CST | |
2547 && tree_int_cst_sgn (vr0.min) >= 0 | |
2548 && tree_int_cst_sgn (vr1.min) >= 0) | |
2549 { | |
2550 double_int vr0_max = tree_to_double_int (vr0.max); | |
2551 double_int vr1_max = tree_to_double_int (vr1.max); | |
2552 double_int ior_max; | |
2553 | |
2554 /* Set all bits to the right of the most significant one to 1. | |
2555 For example, [0, 4] | [4, 4] = [4, 7]. */ | |
2556 ior_max.low = vr0_max.low | vr1_max.low; | |
2557 ior_max.high = vr0_max.high | vr1_max.high; | |
2558 if (ior_max.high != 0) | |
2559 { | |
2560 ior_max.low = ~(unsigned HOST_WIDE_INT)0u; | |
2561 ior_max.high |= ((HOST_WIDE_INT) 1 | |
2562 << floor_log2 (ior_max.high)) - 1; | |
2563 } | |
2564 else if (ior_max.low != 0) | |
2565 ior_max.low |= ((unsigned HOST_WIDE_INT) 1u | |
2566 << floor_log2 (ior_max.low)) - 1; | |
2567 | |
2568 /* Both of these endpoints are conservative. */ | |
2569 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min); | |
2570 max = double_int_to_tree (expr_type, ior_max); | |
2571 } | |
2572 else | |
2573 { | |
2574 set_value_range_to_varying (vr); | |
2575 return; | |
2576 } | |
2577 } | |
2578 else | |
2579 gcc_unreachable (); | |
2580 | |
2581 /* If either MIN or MAX overflowed, then set the resulting range to | |
2582 VARYING. But we do accept an overflow infinity | |
2583 representation. */ | |
2584 if (min == NULL_TREE | |
2585 || !is_gimple_min_invariant (min) | |
2586 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min)) | |
2587 || max == NULL_TREE | |
2588 || !is_gimple_min_invariant (max) | |
2589 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max))) | |
2590 { | |
2591 set_value_range_to_varying (vr); | |
2592 return; | |
2593 } | |
2594 | |
2595 /* We punt if: | |
2596 1) [-INF, +INF] | |
2597 2) [-INF, +-INF(OVF)] | |
2598 3) [+-INF(OVF), +INF] | |
2599 4) [+-INF(OVF), +-INF(OVF)] | |
2600 We learn nothing when we have INF and INF(OVF) on both sides. | |
2601 Note that we do accept [-INF, -INF] and [+INF, +INF] without | |
2602 overflow. */ | |
2603 if ((vrp_val_is_min (min) || is_overflow_infinity (min)) | |
2604 && (vrp_val_is_max (max) || is_overflow_infinity (max))) | |
2605 { | |
2606 set_value_range_to_varying (vr); | |
2607 return; | |
2608 } | |
2609 | |
2610 cmp = compare_values (min, max); | |
2611 if (cmp == -2 || cmp == 1) | |
2612 { | |
2613 /* If the new range has its limits swapped around (MIN > MAX), | |
2614 then the operation caused one of them to wrap around, mark | |
2615 the new range VARYING. */ | |
2616 set_value_range_to_varying (vr); | |
2617 } | |
2618 else | |
2619 set_value_range (vr, type, min, max, NULL); | |
2620 } | |
2621 | |
2622 | |
2623 /* Extract range information from a unary expression EXPR based on | |
2624 the range of its operand and the expression code. */ | |
2625 | |
2626 static void | |
2627 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code, | |
2628 tree type, tree op0) | |
2629 { | |
2630 tree min, max; | |
2631 int cmp; | |
2632 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL }; | |
2633 | |
2634 /* Refuse to operate on certain unary expressions for which we | |
2635 cannot easily determine a resulting range. */ | |
2636 if (code == FIX_TRUNC_EXPR | |
2637 || code == FLOAT_EXPR | |
2638 || code == BIT_NOT_EXPR | |
2639 || code == CONJ_EXPR) | |
2640 { | |
2641 /* We can still do constant propagation here. */ | |
2642 if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE) | |
2643 { | |
2644 tree tem = fold_unary (code, type, op0); | |
2645 if (tem | |
2646 && is_gimple_min_invariant (tem) | |
2647 && !is_overflow_infinity (tem)) | |
2648 { | |
2649 set_value_range (vr, VR_RANGE, tem, tem, NULL); | |
2650 return; | |
2651 } | |
2652 } | |
2653 set_value_range_to_varying (vr); | |
2654 return; | |
2655 } | |
2656 | |
2657 /* Get value ranges for the operand. For constant operands, create | |
2658 a new value range with the operand to simplify processing. */ | |
2659 if (TREE_CODE (op0) == SSA_NAME) | |
2660 vr0 = *(get_value_range (op0)); | |
2661 else if (is_gimple_min_invariant (op0)) | |
2662 set_value_range_to_value (&vr0, op0, NULL); | |
2663 else | |
2664 set_value_range_to_varying (&vr0); | |
2665 | |
2666 /* If VR0 is UNDEFINED, so is the result. */ | |
2667 if (vr0.type == VR_UNDEFINED) | |
2668 { | |
2669 set_value_range_to_undefined (vr); | |
2670 return; | |
2671 } | |
2672 | |
2673 /* Refuse to operate on symbolic ranges, or if neither operand is | |
2674 a pointer or integral type. */ | |
2675 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0)) | |
2676 && !POINTER_TYPE_P (TREE_TYPE (op0))) | |
2677 || (vr0.type != VR_VARYING | |
2678 && symbolic_range_p (&vr0))) | |
2679 { | |
2680 set_value_range_to_varying (vr); | |
2681 return; | |
2682 } | |
2683 | |
2684 /* If the expression involves pointers, we are only interested in | |
2685 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */ | |
2686 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0))) | |
2687 { | |
2688 bool sop; | |
2689 | |
2690 sop = false; | |
2691 if (range_is_nonnull (&vr0) | |
2692 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop) | |
2693 && !sop)) | |
2694 set_value_range_to_nonnull (vr, type); | |
2695 else if (range_is_null (&vr0)) | |
2696 set_value_range_to_null (vr, type); | |
2697 else | |
2698 set_value_range_to_varying (vr); | |
2699 | |
2700 return; | |
2701 } | |
2702 | |
2703 /* Handle unary expressions on integer ranges. */ | |
2704 if (CONVERT_EXPR_CODE_P (code) | |
2705 && INTEGRAL_TYPE_P (type) | |
2706 && INTEGRAL_TYPE_P (TREE_TYPE (op0))) | |
2707 { | |
2708 tree inner_type = TREE_TYPE (op0); | |
2709 tree outer_type = type; | |
2710 | |
2711 /* Always use base-types here. This is important for the | |
2712 correct signedness. */ | |
2713 if (TREE_TYPE (inner_type)) | |
2714 inner_type = TREE_TYPE (inner_type); | |
2715 if (TREE_TYPE (outer_type)) | |
2716 outer_type = TREE_TYPE (outer_type); | |
2717 | |
2718 /* If VR0 is varying and we increase the type precision, assume | |
2719 a full range for the following transformation. */ | |
2720 if (vr0.type == VR_VARYING | |
2721 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type)) | |
2722 { | |
2723 vr0.type = VR_RANGE; | |
2724 vr0.min = TYPE_MIN_VALUE (inner_type); | |
2725 vr0.max = TYPE_MAX_VALUE (inner_type); | |
2726 } | |
2727 | |
2728 /* If VR0 is a constant range or anti-range and the conversion is | |
2729 not truncating we can convert the min and max values and | |
2730 canonicalize the resulting range. Otherwise we can do the | |
2731 conversion if the size of the range is less than what the | |
2732 precision of the target type can represent and the range is | |
2733 not an anti-range. */ | |
2734 if ((vr0.type == VR_RANGE | |
2735 || vr0.type == VR_ANTI_RANGE) | |
2736 && TREE_CODE (vr0.min) == INTEGER_CST | |
2737 && TREE_CODE (vr0.max) == INTEGER_CST | |
2738 && !is_overflow_infinity (vr0.min) | |
2739 && !is_overflow_infinity (vr0.max) | |
2740 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type) | |
2741 || (vr0.type == VR_RANGE | |
2742 && integer_zerop (int_const_binop (RSHIFT_EXPR, | |
2743 int_const_binop (MINUS_EXPR, vr0.max, vr0.min, 0), | |
2744 size_int (TYPE_PRECISION (outer_type)), 0))))) | |
2745 { | |
2746 tree new_min, new_max; | |
2747 new_min = force_fit_type_double (outer_type, | |
2748 TREE_INT_CST_LOW (vr0.min), | |
2749 TREE_INT_CST_HIGH (vr0.min), 0, 0); | |
2750 new_max = force_fit_type_double (outer_type, | |
2751 TREE_INT_CST_LOW (vr0.max), | |
2752 TREE_INT_CST_HIGH (vr0.max), 0, 0); | |
2753 set_and_canonicalize_value_range (vr, vr0.type, | |
2754 new_min, new_max, NULL); | |
2755 return; | |
2756 } | |
2757 | |
2758 set_value_range_to_varying (vr); | |
2759 return; | |
2760 } | |
2761 | |
2762 /* Conversion of a VR_VARYING value to a wider type can result | |
2763 in a usable range. So wait until after we've handled conversions | |
2764 before dropping the result to VR_VARYING if we had a source | |
2765 operand that is VR_VARYING. */ | |
2766 if (vr0.type == VR_VARYING) | |
2767 { | |
2768 set_value_range_to_varying (vr); | |
2769 return; | |
2770 } | |
2771 | |
2772 /* Apply the operation to each end of the range and see what we end | |
2773 up with. */ | |
2774 if (code == NEGATE_EXPR | |
2775 && !TYPE_UNSIGNED (type)) | |
2776 { | |
2777 /* NEGATE_EXPR flips the range around. We need to treat | |
2778 TYPE_MIN_VALUE specially. */ | |
2779 if (is_positive_overflow_infinity (vr0.max)) | |
2780 min = negative_overflow_infinity (type); | |
2781 else if (is_negative_overflow_infinity (vr0.max)) | |
2782 min = positive_overflow_infinity (type); | |
2783 else if (!vrp_val_is_min (vr0.max)) | |
2784 min = fold_unary_to_constant (code, type, vr0.max); | |
2785 else if (needs_overflow_infinity (type)) | |
2786 { | |
2787 if (supports_overflow_infinity (type) | |
2788 && !is_overflow_infinity (vr0.min) | |
2789 && !vrp_val_is_min (vr0.min)) | |
2790 min = positive_overflow_infinity (type); | |
2791 else | |
2792 { | |
2793 set_value_range_to_varying (vr); | |
2794 return; | |
2795 } | |
2796 } | |
2797 else | |
2798 min = TYPE_MIN_VALUE (type); | |
2799 | |
2800 if (is_positive_overflow_infinity (vr0.min)) | |
2801 max = negative_overflow_infinity (type); | |
2802 else if (is_negative_overflow_infinity (vr0.min)) | |
2803 max = positive_overflow_infinity (type); | |
2804 else if (!vrp_val_is_min (vr0.min)) | |
2805 max = fold_unary_to_constant (code, type, vr0.min); | |
2806 else if (needs_overflow_infinity (type)) | |
2807 { | |
2808 if (supports_overflow_infinity (type)) | |
2809 max = positive_overflow_infinity (type); | |
2810 else | |
2811 { | |
2812 set_value_range_to_varying (vr); | |
2813 return; | |
2814 } | |
2815 } | |
2816 else | |
2817 max = TYPE_MIN_VALUE (type); | |
2818 } | |
2819 else if (code == NEGATE_EXPR | |
2820 && TYPE_UNSIGNED (type)) | |
2821 { | |
2822 if (!range_includes_zero_p (&vr0)) | |
2823 { | |
2824 max = fold_unary_to_constant (code, type, vr0.min); | |
2825 min = fold_unary_to_constant (code, type, vr0.max); | |
2826 } | |
2827 else | |
2828 { | |
2829 if (range_is_null (&vr0)) | |
2830 set_value_range_to_null (vr, type); | |
2831 else | |
2832 set_value_range_to_varying (vr); | |
2833 return; | |
2834 } | |
2835 } | |
2836 else if (code == ABS_EXPR | |
2837 && !TYPE_UNSIGNED (type)) | |
2838 { | |
2839 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a | |
2840 useful range. */ | |
2841 if (!TYPE_OVERFLOW_UNDEFINED (type) | |
2842 && ((vr0.type == VR_RANGE | |
2843 && vrp_val_is_min (vr0.min)) | |
2844 || (vr0.type == VR_ANTI_RANGE | |
2845 && !vrp_val_is_min (vr0.min) | |
2846 && !range_includes_zero_p (&vr0)))) | |
2847 { | |
2848 set_value_range_to_varying (vr); | |
2849 return; | |
2850 } | |
2851 | |
2852 /* ABS_EXPR may flip the range around, if the original range | |
2853 included negative values. */ | |
2854 if (is_overflow_infinity (vr0.min)) | |
2855 min = positive_overflow_infinity (type); | |
2856 else if (!vrp_val_is_min (vr0.min)) | |
2857 min = fold_unary_to_constant (code, type, vr0.min); | |
2858 else if (!needs_overflow_infinity (type)) | |
2859 min = TYPE_MAX_VALUE (type); | |
2860 else if (supports_overflow_infinity (type)) | |
2861 min = positive_overflow_infinity (type); | |
2862 else | |
2863 { | |
2864 set_value_range_to_varying (vr); | |
2865 return; | |
2866 } | |
2867 | |
2868 if (is_overflow_infinity (vr0.max)) | |
2869 max = positive_overflow_infinity (type); | |
2870 else if (!vrp_val_is_min (vr0.max)) | |
2871 max = fold_unary_to_constant (code, type, vr0.max); | |
2872 else if (!needs_overflow_infinity (type)) | |
2873 max = TYPE_MAX_VALUE (type); | |
2874 else if (supports_overflow_infinity (type) | |
2875 /* We shouldn't generate [+INF, +INF] as set_value_range | |
2876 doesn't like this and ICEs. */ | |
2877 && !is_positive_overflow_infinity (min)) | |
2878 max = positive_overflow_infinity (type); | |
2879 else | |
2880 { | |
2881 set_value_range_to_varying (vr); | |
2882 return; | |
2883 } | |
2884 | |
2885 cmp = compare_values (min, max); | |
2886 | |
2887 /* If a VR_ANTI_RANGEs contains zero, then we have | |
2888 ~[-INF, min(MIN, MAX)]. */ | |
2889 if (vr0.type == VR_ANTI_RANGE) | |
2890 { | |
2891 if (range_includes_zero_p (&vr0)) | |
2892 { | |
2893 /* Take the lower of the two values. */ | |
2894 if (cmp != 1) | |
2895 max = min; | |
2896 | |
2897 /* Create ~[-INF, min (abs(MIN), abs(MAX))] | |
2898 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when | |
2899 flag_wrapv is set and the original anti-range doesn't include | |
2900 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */ | |
2901 if (TYPE_OVERFLOW_WRAPS (type)) | |
2902 { | |
2903 tree type_min_value = TYPE_MIN_VALUE (type); | |
2904 | |
2905 min = (vr0.min != type_min_value | |
2906 ? int_const_binop (PLUS_EXPR, type_min_value, | |
2907 integer_one_node, 0) | |
2908 : type_min_value); | |
2909 } | |
2910 else | |
2911 { | |
2912 if (overflow_infinity_range_p (&vr0)) | |
2913 min = negative_overflow_infinity (type); | |
2914 else | |
2915 min = TYPE_MIN_VALUE (type); | |
2916 } | |
2917 } | |
2918 else | |
2919 { | |
2920 /* All else has failed, so create the range [0, INF], even for | |
2921 flag_wrapv since TYPE_MIN_VALUE is in the original | |
2922 anti-range. */ | |
2923 vr0.type = VR_RANGE; | |
2924 min = build_int_cst (type, 0); | |
2925 if (needs_overflow_infinity (type)) | |
2926 { | |
2927 if (supports_overflow_infinity (type)) | |
2928 max = positive_overflow_infinity (type); | |
2929 else | |
2930 { | |
2931 set_value_range_to_varying (vr); | |
2932 return; | |
2933 } | |
2934 } | |
2935 else | |
2936 max = TYPE_MAX_VALUE (type); | |
2937 } | |
2938 } | |
2939 | |
2940 /* If the range contains zero then we know that the minimum value in the | |
2941 range will be zero. */ | |
2942 else if (range_includes_zero_p (&vr0)) | |
2943 { | |
2944 if (cmp == 1) | |
2945 max = min; | |
2946 min = build_int_cst (type, 0); | |
2947 } | |
2948 else | |
2949 { | |
2950 /* If the range was reversed, swap MIN and MAX. */ | |
2951 if (cmp == 1) | |
2952 { | |
2953 tree t = min; | |
2954 min = max; | |
2955 max = t; | |
2956 } | |
2957 } | |
2958 } | |
2959 else | |
2960 { | |
2961 /* Otherwise, operate on each end of the range. */ | |
2962 min = fold_unary_to_constant (code, type, vr0.min); | |
2963 max = fold_unary_to_constant (code, type, vr0.max); | |
2964 | |
2965 if (needs_overflow_infinity (type)) | |
2966 { | |
2967 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR); | |
2968 | |
2969 /* If both sides have overflowed, we don't know | |
2970 anything. */ | |
2971 if ((is_overflow_infinity (vr0.min) | |
2972 || TREE_OVERFLOW (min)) | |
2973 && (is_overflow_infinity (vr0.max) | |
2974 || TREE_OVERFLOW (max))) | |
2975 { | |
2976 set_value_range_to_varying (vr); | |
2977 return; | |
2978 } | |
2979 | |
2980 if (is_overflow_infinity (vr0.min)) | |
2981 min = vr0.min; | |
2982 else if (TREE_OVERFLOW (min)) | |
2983 { | |
2984 if (supports_overflow_infinity (type)) | |
2985 min = (tree_int_cst_sgn (min) >= 0 | |
2986 ? positive_overflow_infinity (TREE_TYPE (min)) | |
2987 : negative_overflow_infinity (TREE_TYPE (min))); | |
2988 else | |
2989 { | |
2990 set_value_range_to_varying (vr); | |
2991 return; | |
2992 } | |
2993 } | |
2994 | |
2995 if (is_overflow_infinity (vr0.max)) | |
2996 max = vr0.max; | |
2997 else if (TREE_OVERFLOW (max)) | |
2998 { | |
2999 if (supports_overflow_infinity (type)) | |
3000 max = (tree_int_cst_sgn (max) >= 0 | |
3001 ? positive_overflow_infinity (TREE_TYPE (max)) | |
3002 : negative_overflow_infinity (TREE_TYPE (max))); | |
3003 else | |
3004 { | |
3005 set_value_range_to_varying (vr); | |
3006 return; | |
3007 } | |
3008 } | |
3009 } | |
3010 } | |
3011 | |
3012 cmp = compare_values (min, max); | |
3013 if (cmp == -2 || cmp == 1) | |
3014 { | |
3015 /* If the new range has its limits swapped around (MIN > MAX), | |
3016 then the operation caused one of them to wrap around, mark | |
3017 the new range VARYING. */ | |
3018 set_value_range_to_varying (vr); | |
3019 } | |
3020 else | |
3021 set_value_range (vr, vr0.type, min, max, NULL); | |
3022 } | |
3023 | |
3024 | |
3025 /* Extract range information from a conditional expression EXPR based on | |
3026 the ranges of each of its operands and the expression code. */ | |
3027 | |
3028 static void | |
3029 extract_range_from_cond_expr (value_range_t *vr, tree expr) | |
3030 { | |
3031 tree op0, op1; | |
3032 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL }; | |
3033 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL }; | |
3034 | |
3035 /* Get value ranges for each operand. For constant operands, create | |
3036 a new value range with the operand to simplify processing. */ | |
3037 op0 = COND_EXPR_THEN (expr); | |
3038 if (TREE_CODE (op0) == SSA_NAME) | |
3039 vr0 = *(get_value_range (op0)); | |
3040 else if (is_gimple_min_invariant (op0)) | |
3041 set_value_range_to_value (&vr0, op0, NULL); | |
3042 else | |
3043 set_value_range_to_varying (&vr0); | |
3044 | |
3045 op1 = COND_EXPR_ELSE (expr); | |
3046 if (TREE_CODE (op1) == SSA_NAME) | |
3047 vr1 = *(get_value_range (op1)); | |
3048 else if (is_gimple_min_invariant (op1)) | |
3049 set_value_range_to_value (&vr1, op1, NULL); | |
3050 else | |
3051 set_value_range_to_varying (&vr1); | |
3052 | |
3053 /* The resulting value range is the union of the operand ranges */ | |
3054 vrp_meet (&vr0, &vr1); | |
3055 copy_value_range (vr, &vr0); | |
3056 } | |
3057 | |
3058 | |
3059 /* Extract range information from a comparison expression EXPR based | |
3060 on the range of its operand and the expression code. */ | |
3061 | |
3062 static void | |
3063 extract_range_from_comparison (value_range_t *vr, enum tree_code code, | |
3064 tree type, tree op0, tree op1) | |
3065 { | |
3066 bool sop = false; | |
3067 tree val; | |
3068 | |
3069 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop, | |
3070 NULL); | |
3071 | |
3072 /* A disadvantage of using a special infinity as an overflow | |
3073 representation is that we lose the ability to record overflow | |
3074 when we don't have an infinity. So we have to ignore a result | |
3075 which relies on overflow. */ | |
3076 | |
3077 if (val && !is_overflow_infinity (val) && !sop) | |
3078 { | |
3079 /* Since this expression was found on the RHS of an assignment, | |
3080 its type may be different from _Bool. Convert VAL to EXPR's | |
3081 type. */ | |
3082 val = fold_convert (type, val); | |
3083 if (is_gimple_min_invariant (val)) | |
3084 set_value_range_to_value (vr, val, vr->equiv); | |
3085 else | |
3086 set_value_range (vr, VR_RANGE, val, val, vr->equiv); | |
3087 } | |
3088 else | |
3089 /* The result of a comparison is always true or false. */ | |
3090 set_value_range_to_truthvalue (vr, type); | |
3091 } | |
3092 | |
3093 /* Try to derive a nonnegative or nonzero range out of STMT relying | |
3094 primarily on generic routines in fold in conjunction with range data. | |
3095 Store the result in *VR */ | |
3096 | |
3097 static void | |
3098 extract_range_basic (value_range_t *vr, gimple stmt) | |
3099 { | |
3100 bool sop = false; | |
3101 tree type = gimple_expr_type (stmt); | |
3102 | |
3103 if (INTEGRAL_TYPE_P (type) | |
3104 && gimple_stmt_nonnegative_warnv_p (stmt, &sop)) | |
3105 set_value_range_to_nonnegative (vr, type, | |
3106 sop || stmt_overflow_infinity (stmt)); | |
3107 else if (vrp_stmt_computes_nonzero (stmt, &sop) | |
3108 && !sop) | |
3109 set_value_range_to_nonnull (vr, type); | |
3110 else | |
3111 set_value_range_to_varying (vr); | |
3112 } | |
3113 | |
3114 | |
3115 /* Try to compute a useful range out of assignment STMT and store it | |
3116 in *VR. */ | |
3117 | |
3118 static void | |
3119 extract_range_from_assignment (value_range_t *vr, gimple stmt) | |
3120 { | |
3121 enum tree_code code = gimple_assign_rhs_code (stmt); | |
3122 | |
3123 if (code == ASSERT_EXPR) | |
3124 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt)); | |
3125 else if (code == SSA_NAME) | |
3126 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt)); | |
3127 else if (TREE_CODE_CLASS (code) == tcc_binary | |
3128 || code == TRUTH_AND_EXPR | |
3129 || code == TRUTH_OR_EXPR | |
3130 || code == TRUTH_XOR_EXPR) | |
3131 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt), | |
3132 gimple_expr_type (stmt), | |
3133 gimple_assign_rhs1 (stmt), | |
3134 gimple_assign_rhs2 (stmt)); | |
3135 else if (TREE_CODE_CLASS (code) == tcc_unary) | |
3136 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt), | |
3137 gimple_expr_type (stmt), | |
3138 gimple_assign_rhs1 (stmt)); | |
3139 else if (code == COND_EXPR) | |
3140 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt)); | |
3141 else if (TREE_CODE_CLASS (code) == tcc_comparison) | |
3142 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt), | |
3143 gimple_expr_type (stmt), | |
3144 gimple_assign_rhs1 (stmt), | |
3145 gimple_assign_rhs2 (stmt)); | |
3146 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS | |
3147 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt))) | |
3148 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL); | |
3149 else | |
3150 set_value_range_to_varying (vr); | |
3151 | |
3152 if (vr->type == VR_VARYING) | |
3153 extract_range_basic (vr, stmt); | |
3154 } | |
3155 | |
3156 /* Given a range VR, a LOOP and a variable VAR, determine whether it | |
3157 would be profitable to adjust VR using scalar evolution information | |
3158 for VAR. If so, update VR with the new limits. */ | |
3159 | |
3160 static void | |
3161 adjust_range_with_scev (value_range_t *vr, struct loop *loop, | |
3162 gimple stmt, tree var) | |
3163 { | |
3164 tree init, step, chrec, tmin, tmax, min, max, type; | |
3165 enum ev_direction dir; | |
3166 | |
3167 /* TODO. Don't adjust anti-ranges. An anti-range may provide | |
3168 better opportunities than a regular range, but I'm not sure. */ | |
3169 if (vr->type == VR_ANTI_RANGE) | |
3170 return; | |
3171 | |
3172 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var)); | |
3173 | |
3174 /* Like in PR19590, scev can return a constant function. */ | |
3175 if (is_gimple_min_invariant (chrec)) | |
3176 { | |
3177 set_value_range_to_value (vr, chrec, vr->equiv); | |
3178 return; | |
3179 } | |
3180 | |
3181 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC) | |
3182 return; | |
3183 | |
3184 init = initial_condition_in_loop_num (chrec, loop->num); | |
3185 step = evolution_part_in_loop_num (chrec, loop->num); | |
3186 | |
3187 /* If STEP is symbolic, we can't know whether INIT will be the | |
3188 minimum or maximum value in the range. Also, unless INIT is | |
3189 a simple expression, compare_values and possibly other functions | |
3190 in tree-vrp won't be able to handle it. */ | |
3191 if (step == NULL_TREE | |
3192 || !is_gimple_min_invariant (step) | |
3193 || !valid_value_p (init)) | |
3194 return; | |
3195 | |
3196 dir = scev_direction (chrec); | |
3197 if (/* Do not adjust ranges if we do not know whether the iv increases | |
3198 or decreases, ... */ | |
3199 dir == EV_DIR_UNKNOWN | |
3200 /* ... or if it may wrap. */ | |
3201 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec), | |
3202 true)) | |
3203 return; | |
3204 | |
3205 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of | |
3206 negative_overflow_infinity and positive_overflow_infinity, | |
3207 because we have concluded that the loop probably does not | |
3208 wrap. */ | |
3209 | |
3210 type = TREE_TYPE (var); | |
3211 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type)) | |
3212 tmin = lower_bound_in_type (type, type); | |
3213 else | |
3214 tmin = TYPE_MIN_VALUE (type); | |
3215 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type)) | |
3216 tmax = upper_bound_in_type (type, type); | |
3217 else | |
3218 tmax = TYPE_MAX_VALUE (type); | |
3219 | |
3220 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED) | |
3221 { | |
3222 min = tmin; | |
3223 max = tmax; | |
3224 | |
3225 /* For VARYING or UNDEFINED ranges, just about anything we get | |
3226 from scalar evolutions should be better. */ | |
3227 | |
3228 if (dir == EV_DIR_DECREASES) | |
3229 max = init; | |
3230 else | |
3231 min = init; | |
3232 | |
3233 /* If we would create an invalid range, then just assume we | |
3234 know absolutely nothing. This may be over-conservative, | |
3235 but it's clearly safe, and should happen only in unreachable | |
3236 parts of code, or for invalid programs. */ | |
3237 if (compare_values (min, max) == 1) | |
3238 return; | |
3239 | |
3240 set_value_range (vr, VR_RANGE, min, max, vr->equiv); | |
3241 } | |
3242 else if (vr->type == VR_RANGE) | |
3243 { | |
3244 min = vr->min; | |
3245 max = vr->max; | |
3246 | |
3247 if (dir == EV_DIR_DECREASES) | |
3248 { | |
3249 /* INIT is the maximum value. If INIT is lower than VR->MAX | |
3250 but no smaller than VR->MIN, set VR->MAX to INIT. */ | |
3251 if (compare_values (init, max) == -1) | |
3252 { | |
3253 max = init; | |
3254 | |
3255 /* If we just created an invalid range with the minimum | |
3256 greater than the maximum, we fail conservatively. | |
3257 This should happen only in unreachable | |
3258 parts of code, or for invalid programs. */ | |
3259 if (compare_values (min, max) == 1) | |
3260 return; | |
3261 } | |
3262 | |
3263 /* According to the loop information, the variable does not | |
3264 overflow. If we think it does, probably because of an | |
3265 overflow due to arithmetic on a different INF value, | |
3266 reset now. */ | |
3267 if (is_negative_overflow_infinity (min)) | |
3268 min = tmin; | |
3269 } | |
3270 else | |
3271 { | |
3272 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */ | |
3273 if (compare_values (init, min) == 1) | |
3274 { | |
3275 min = init; | |
3276 | |
3277 /* Again, avoid creating invalid range by failing. */ | |
3278 if (compare_values (min, max) == 1) | |
3279 return; | |
3280 } | |
3281 | |
3282 if (is_positive_overflow_infinity (max)) | |
3283 max = tmax; | |
3284 } | |
3285 | |
3286 set_value_range (vr, VR_RANGE, min, max, vr->equiv); | |
3287 } | |
3288 } | |
3289 | |
3290 /* Return true if VAR may overflow at STMT. This checks any available | |
3291 loop information to see if we can determine that VAR does not | |
3292 overflow. */ | |
3293 | |
3294 static bool | |
3295 vrp_var_may_overflow (tree var, gimple stmt) | |
3296 { | |
3297 struct loop *l; | |
3298 tree chrec, init, step; | |
3299 | |
3300 if (current_loops == NULL) | |
3301 return true; | |
3302 | |
3303 l = loop_containing_stmt (stmt); | |
3304 if (l == NULL) | |
3305 return true; | |
3306 | |
3307 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var)); | |
3308 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC) | |
3309 return true; | |
3310 | |
3311 init = initial_condition_in_loop_num (chrec, l->num); | |
3312 step = evolution_part_in_loop_num (chrec, l->num); | |
3313 | |
3314 if (step == NULL_TREE | |
3315 || !is_gimple_min_invariant (step) | |
3316 || !valid_value_p (init)) | |
3317 return true; | |
3318 | |
3319 /* If we get here, we know something useful about VAR based on the | |
3320 loop information. If it wraps, it may overflow. */ | |
3321 | |
3322 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec), | |
3323 true)) | |
3324 return true; | |
3325 | |
3326 if (dump_file && (dump_flags & TDF_DETAILS) != 0) | |
3327 { | |
3328 print_generic_expr (dump_file, var, 0); | |
3329 fprintf (dump_file, ": loop information indicates does not overflow\n"); | |
3330 } | |
3331 | |
3332 return false; | |
3333 } | |
3334 | |
3335 | |
3336 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP: | |
3337 | |
3338 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for | |
3339 all the values in the ranges. | |
3340 | |
3341 - Return BOOLEAN_FALSE_NODE if the comparison always returns false. | |
3342 | |
3343 - Return NULL_TREE if it is not always possible to determine the | |
3344 value of the comparison. | |
3345 | |
3346 Also set *STRICT_OVERFLOW_P to indicate whether a range with an | |
3347 overflow infinity was used in the test. */ | |
3348 | |
3349 | |
3350 static tree | |
3351 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1, | |
3352 bool *strict_overflow_p) | |
3353 { | |
3354 /* VARYING or UNDEFINED ranges cannot be compared. */ | |
3355 if (vr0->type == VR_VARYING | |
3356 || vr0->type == VR_UNDEFINED | |
3357 || vr1->type == VR_VARYING | |
3358 || vr1->type == VR_UNDEFINED) | |
3359 return NULL_TREE; | |
3360 | |
3361 /* Anti-ranges need to be handled separately. */ | |
3362 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE) | |
3363 { | |
3364 /* If both are anti-ranges, then we cannot compute any | |
3365 comparison. */ | |
3366 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE) | |
3367 return NULL_TREE; | |
3368 | |
3369 /* These comparisons are never statically computable. */ | |
3370 if (comp == GT_EXPR | |
3371 || comp == GE_EXPR | |
3372 || comp == LT_EXPR | |
3373 || comp == LE_EXPR) | |
3374 return NULL_TREE; | |
3375 | |
3376 /* Equality can be computed only between a range and an | |
3377 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */ | |
3378 if (vr0->type == VR_RANGE) | |
3379 { | |
3380 /* To simplify processing, make VR0 the anti-range. */ | |
3381 value_range_t *tmp = vr0; | |
3382 vr0 = vr1; | |
3383 vr1 = tmp; | |
3384 } | |
3385 | |
3386 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR); | |
3387 | |
3388 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0 | |
3389 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0) | |
3390 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node; | |
3391 | |
3392 return NULL_TREE; | |
3393 } | |
3394 | |
3395 if (!usable_range_p (vr0, strict_overflow_p) | |
3396 || !usable_range_p (vr1, strict_overflow_p)) | |
3397 return NULL_TREE; | |
3398 | |
3399 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the | |
3400 operands around and change the comparison code. */ | |
3401 if (comp == GT_EXPR || comp == GE_EXPR) | |
3402 { | |
3403 value_range_t *tmp; | |
3404 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR; | |
3405 tmp = vr0; | |
3406 vr0 = vr1; | |
3407 vr1 = tmp; | |
3408 } | |
3409 | |
3410 if (comp == EQ_EXPR) | |
3411 { | |
3412 /* Equality may only be computed if both ranges represent | |
3413 exactly one value. */ | |
3414 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0 | |
3415 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0) | |
3416 { | |
3417 int cmp_min = compare_values_warnv (vr0->min, vr1->min, | |
3418 strict_overflow_p); | |
3419 int cmp_max = compare_values_warnv (vr0->max, vr1->max, | |
3420 strict_overflow_p); | |
3421 if (cmp_min == 0 && cmp_max == 0) | |
3422 return boolean_true_node; | |
3423 else if (cmp_min != -2 && cmp_max != -2) | |
3424 return boolean_false_node; | |
3425 } | |
3426 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */ | |
3427 else if (compare_values_warnv (vr0->min, vr1->max, | |
3428 strict_overflow_p) == 1 | |
3429 || compare_values_warnv (vr1->min, vr0->max, | |
3430 strict_overflow_p) == 1) | |
3431 return boolean_false_node; | |
3432 | |
3433 return NULL_TREE; | |
3434 } | |
3435 else if (comp == NE_EXPR) | |
3436 { | |
3437 int cmp1, cmp2; | |
3438 | |
3439 /* If VR0 is completely to the left or completely to the right | |
3440 of VR1, they are always different. Notice that we need to | |
3441 make sure that both comparisons yield similar results to | |
3442 avoid comparing values that cannot be compared at | |
3443 compile-time. */ | |
3444 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p); | |
3445 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p); | |
3446 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1)) | |
3447 return boolean_true_node; | |
3448 | |
3449 /* If VR0 and VR1 represent a single value and are identical, | |
3450 return false. */ | |
3451 else if (compare_values_warnv (vr0->min, vr0->max, | |
3452 strict_overflow_p) == 0 | |
3453 && compare_values_warnv (vr1->min, vr1->max, | |
3454 strict_overflow_p) == 0 | |
3455 && compare_values_warnv (vr0->min, vr1->min, | |
3456 strict_overflow_p) == 0 | |
3457 && compare_values_warnv (vr0->max, vr1->max, | |
3458 strict_overflow_p) == 0) | |
3459 return boolean_false_node; | |
3460 | |
3461 /* Otherwise, they may or may not be different. */ | |
3462 else | |
3463 return NULL_TREE; | |
3464 } | |
3465 else if (comp == LT_EXPR || comp == LE_EXPR) | |
3466 { | |
3467 int tst; | |
3468 | |
3469 /* If VR0 is to the left of VR1, return true. */ | |
3470 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p); | |
3471 if ((comp == LT_EXPR && tst == -1) | |
3472 || (comp == LE_EXPR && (tst == -1 || tst == 0))) | |
3473 { | |
3474 if (overflow_infinity_range_p (vr0) | |
3475 || overflow_infinity_range_p (vr1)) | |
3476 *strict_overflow_p = true; | |
3477 return boolean_true_node; | |
3478 } | |
3479 | |
3480 /* If VR0 is to the right of VR1, return false. */ | |
3481 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p); | |
3482 if ((comp == LT_EXPR && (tst == 0 || tst == 1)) | |
3483 || (comp == LE_EXPR && tst == 1)) | |
3484 { | |
3485 if (overflow_infinity_range_p (vr0) | |
3486 || overflow_infinity_range_p (vr1)) | |
3487 *strict_overflow_p = true; | |
3488 return boolean_false_node; | |
3489 } | |
3490 | |
3491 /* Otherwise, we don't know. */ | |
3492 return NULL_TREE; | |
3493 } | |
3494 | |
3495 gcc_unreachable (); | |
3496 } | |
3497 | |
3498 | |
3499 /* Given a value range VR, a value VAL and a comparison code COMP, return | |
3500 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the | |
3501 values in VR. Return BOOLEAN_FALSE_NODE if the comparison | |
3502 always returns false. Return NULL_TREE if it is not always | |
3503 possible to determine the value of the comparison. Also set | |
3504 *STRICT_OVERFLOW_P to indicate whether a range with an overflow | |
3505 infinity was used in the test. */ | |
3506 | |
3507 static tree | |
3508 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val, | |
3509 bool *strict_overflow_p) | |
3510 { | |
3511 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED) | |
3512 return NULL_TREE; | |
3513 | |
3514 /* Anti-ranges need to be handled separately. */ | |
3515 if (vr->type == VR_ANTI_RANGE) | |
3516 { | |
3517 /* For anti-ranges, the only predicates that we can compute at | |
3518 compile time are equality and inequality. */ | |
3519 if (comp == GT_EXPR | |
3520 || comp == GE_EXPR | |
3521 || comp == LT_EXPR | |
3522 || comp == LE_EXPR) | |
3523 return NULL_TREE; | |
3524 | |
3525 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */ | |
3526 if (value_inside_range (val, vr) == 1) | |
3527 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node; | |
3528 | |
3529 return NULL_TREE; | |
3530 } | |
3531 | |
3532 if (!usable_range_p (vr, strict_overflow_p)) | |
3533 return NULL_TREE; | |
3534 | |
3535 if (comp == EQ_EXPR) | |
3536 { | |
3537 /* EQ_EXPR may only be computed if VR represents exactly | |
3538 one value. */ | |
3539 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0) | |
3540 { | |
3541 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p); | |
3542 if (cmp == 0) | |
3543 return boolean_true_node; | |
3544 else if (cmp == -1 || cmp == 1 || cmp == 2) | |
3545 return boolean_false_node; | |
3546 } | |
3547 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1 | |
3548 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1) | |
3549 return boolean_false_node; | |
3550 | |
3551 return NULL_TREE; | |
3552 } | |
3553 else if (comp == NE_EXPR) | |
3554 { | |
3555 /* If VAL is not inside VR, then they are always different. */ | |
3556 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1 | |
3557 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1) | |
3558 return boolean_true_node; | |
3559 | |
3560 /* If VR represents exactly one value equal to VAL, then return | |
3561 false. */ | |
3562 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0 | |
3563 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0) | |
3564 return boolean_false_node; | |
3565 | |
3566 /* Otherwise, they may or may not be different. */ | |
3567 return NULL_TREE; | |
3568 } | |
3569 else if (comp == LT_EXPR || comp == LE_EXPR) | |
3570 { | |
3571 int tst; | |
3572 | |
3573 /* If VR is to the left of VAL, return true. */ | |
3574 tst = compare_values_warnv (vr->max, val, strict_overflow_p); | |
3575 if ((comp == LT_EXPR && tst == -1) | |
3576 || (comp == LE_EXPR && (tst == -1 || tst == 0))) | |
3577 { | |
3578 if (overflow_infinity_range_p (vr)) | |
3579 *strict_overflow_p = true; | |
3580 return boolean_true_node; | |
3581 } | |
3582 | |
3583 /* If VR is to the right of VAL, return false. */ | |
3584 tst = compare_values_warnv (vr->min, val, strict_overflow_p); | |
3585 if ((comp == LT_EXPR && (tst == 0 || tst == 1)) | |
3586 || (comp == LE_EXPR && tst == 1)) | |
3587 { | |
3588 if (overflow_infinity_range_p (vr)) | |
3589 *strict_overflow_p = true; | |
3590 return boolean_false_node; | |
3591 } | |
3592 | |
3593 /* Otherwise, we don't know. */ | |
3594 return NULL_TREE; | |
3595 } | |
3596 else if (comp == GT_EXPR || comp == GE_EXPR) | |
3597 { | |
3598 int tst; | |
3599 | |
3600 /* If VR is to the right of VAL, return true. */ | |
3601 tst = compare_values_warnv (vr->min, val, strict_overflow_p); | |
3602 if ((comp == GT_EXPR && tst == 1) | |
3603 || (comp == GE_EXPR && (tst == 0 || tst == 1))) | |
3604 { | |
3605 if (overflow_infinity_range_p (vr)) | |
3606 *strict_overflow_p = true; | |
3607 return boolean_true_node; | |
3608 } | |
3609 | |
3610 /* If VR is to the left of VAL, return false. */ | |
3611 tst = compare_values_warnv (vr->max, val, strict_overflow_p); | |
3612 if ((comp == GT_EXPR && (tst == -1 || tst == 0)) | |
3613 || (comp == GE_EXPR && tst == -1)) | |
3614 { | |
3615 if (overflow_infinity_range_p (vr)) | |
3616 *strict_overflow_p = true; | |
3617 return boolean_false_node; | |
3618 } | |
3619 | |
3620 /* Otherwise, we don't know. */ | |
3621 return NULL_TREE; | |
3622 } | |
3623 | |
3624 gcc_unreachable (); | |
3625 } | |
3626 | |
3627 | |
3628 /* Debugging dumps. */ | |
3629 | |
3630 void dump_value_range (FILE *, value_range_t *); | |
3631 void debug_value_range (value_range_t *); | |
3632 void dump_all_value_ranges (FILE *); | |
3633 void debug_all_value_ranges (void); | |
3634 void dump_vr_equiv (FILE *, bitmap); | |
3635 void debug_vr_equiv (bitmap); | |
3636 | |
3637 | |
3638 /* Dump value range VR to FILE. */ | |
3639 | |
3640 void | |
3641 dump_value_range (FILE *file, value_range_t *vr) | |
3642 { | |
3643 if (vr == NULL) | |
3644 fprintf (file, "[]"); | |
3645 else if (vr->type == VR_UNDEFINED) | |
3646 fprintf (file, "UNDEFINED"); | |
3647 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE) | |
3648 { | |
3649 tree type = TREE_TYPE (vr->min); | |
3650 | |
3651 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : ""); | |
3652 | |
3653 if (is_negative_overflow_infinity (vr->min)) | |
3654 fprintf (file, "-INF(OVF)"); | |
3655 else if (INTEGRAL_TYPE_P (type) | |
3656 && !TYPE_UNSIGNED (type) | |
3657 && vrp_val_is_min (vr->min)) | |
3658 fprintf (file, "-INF"); | |
3659 else | |
3660 print_generic_expr (file, vr->min, 0); | |
3661 | |
3662 fprintf (file, ", "); | |
3663 | |
3664 if (is_positive_overflow_infinity (vr->max)) | |
3665 fprintf (file, "+INF(OVF)"); | |
3666 else if (INTEGRAL_TYPE_P (type) | |
3667 && vrp_val_is_max (vr->max)) | |
3668 fprintf (file, "+INF"); | |
3669 else | |
3670 print_generic_expr (file, vr->max, 0); | |
3671 | |
3672 fprintf (file, "]"); | |
3673 | |
3674 if (vr->equiv) | |
3675 { | |
3676 bitmap_iterator bi; | |
3677 unsigned i, c = 0; | |
3678 | |
3679 fprintf (file, " EQUIVALENCES: { "); | |
3680 | |
3681 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi) | |
3682 { | |
3683 print_generic_expr (file, ssa_name (i), 0); | |
3684 fprintf (file, " "); | |
3685 c++; | |
3686 } | |
3687 | |
3688 fprintf (file, "} (%u elements)", c); | |
3689 } | |
3690 } | |
3691 else if (vr->type == VR_VARYING) | |
3692 fprintf (file, "VARYING"); | |
3693 else | |
3694 fprintf (file, "INVALID RANGE"); | |
3695 } | |
3696 | |
3697 | |
3698 /* Dump value range VR to stderr. */ | |
3699 | |
3700 void | |
3701 debug_value_range (value_range_t *vr) | |
3702 { | |
3703 dump_value_range (stderr, vr); | |
3704 fprintf (stderr, "\n"); | |
3705 } | |
3706 | |
3707 | |
3708 /* Dump value ranges of all SSA_NAMEs to FILE. */ | |
3709 | |
3710 void | |
3711 dump_all_value_ranges (FILE *file) | |
3712 { | |
3713 size_t i; | |
3714 | |
3715 for (i = 0; i < num_ssa_names; i++) | |
3716 { | |
3717 if (vr_value[i]) | |
3718 { | |
3719 print_generic_expr (file, ssa_name (i), 0); | |
3720 fprintf (file, ": "); | |
3721 dump_value_range (file, vr_value[i]); | |
3722 fprintf (file, "\n"); | |
3723 } | |
3724 } | |
3725 | |
3726 fprintf (file, "\n"); | |
3727 } | |
3728 | |
3729 | |
3730 /* Dump all value ranges to stderr. */ | |
3731 | |
3732 void | |
3733 debug_all_value_ranges (void) | |
3734 { | |
3735 dump_all_value_ranges (stderr); | |
3736 } | |
3737 | |
3738 | |
3739 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V, | |
3740 create a new SSA name N and return the assertion assignment | |
3741 'V = ASSERT_EXPR <V, V OP W>'. */ | |
3742 | |
3743 static gimple | |
3744 build_assert_expr_for (tree cond, tree v) | |
3745 { | |
3746 tree n; | |
3747 gimple assertion; | |
3748 | |
3749 gcc_assert (TREE_CODE (v) == SSA_NAME); | |
3750 n = duplicate_ssa_name (v, NULL); | |
3751 | |
3752 if (COMPARISON_CLASS_P (cond)) | |
3753 { | |
3754 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond); | |
3755 assertion = gimple_build_assign (n, a); | |
3756 } | |
3757 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR) | |
3758 { | |
3759 /* Given !V, build the assignment N = false. */ | |
3760 tree op0 = TREE_OPERAND (cond, 0); | |
3761 gcc_assert (op0 == v); | |
3762 assertion = gimple_build_assign (n, boolean_false_node); | |
3763 } | |
3764 else if (TREE_CODE (cond) == SSA_NAME) | |
3765 { | |
3766 /* Given V, build the assignment N = true. */ | |
3767 gcc_assert (v == cond); | |
3768 assertion = gimple_build_assign (n, boolean_true_node); | |
3769 } | |
3770 else | |
3771 gcc_unreachable (); | |
3772 | |
3773 SSA_NAME_DEF_STMT (n) = assertion; | |
3774 | |
3775 /* The new ASSERT_EXPR, creates a new SSA name that replaces the | |
3776 operand of the ASSERT_EXPR. Register the new name and the old one | |
3777 in the replacement table so that we can fix the SSA web after | |
3778 adding all the ASSERT_EXPRs. */ | |
3779 register_new_name_mapping (n, v); | |
3780 | |
3781 return assertion; | |
3782 } | |
3783 | |
3784 | |
3785 /* Return false if EXPR is a predicate expression involving floating | |
3786 point values. */ | |
3787 | |
3788 static inline bool | |
3789 fp_predicate (gimple stmt) | |
3790 { | |
3791 GIMPLE_CHECK (stmt, GIMPLE_COND); | |
3792 | |
3793 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt))); | |
3794 } | |
3795 | |
3796 | |
3797 /* If the range of values taken by OP can be inferred after STMT executes, | |
3798 return the comparison code (COMP_CODE_P) and value (VAL_P) that | |
3799 describes the inferred range. Return true if a range could be | |
3800 inferred. */ | |
3801 | |
3802 static bool | |
3803 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p) | |
3804 { | |
3805 *val_p = NULL_TREE; | |
3806 *comp_code_p = ERROR_MARK; | |
3807 | |
3808 /* Do not attempt to infer anything in names that flow through | |
3809 abnormal edges. */ | |
3810 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op)) | |
3811 return false; | |
3812 | |
3813 /* Similarly, don't infer anything from statements that may throw | |
3814 exceptions. */ | |
3815 if (stmt_could_throw_p (stmt)) | |
3816 return false; | |
3817 | |
3818 /* If STMT is the last statement of a basic block with no | |
3819 successors, there is no point inferring anything about any of its | |
3820 operands. We would not be able to find a proper insertion point | |
3821 for the assertion, anyway. */ | |
3822 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0) | |
3823 return false; | |
3824 | |
3825 /* We can only assume that a pointer dereference will yield | |
3826 non-NULL if -fdelete-null-pointer-checks is enabled. */ | |
3827 if (flag_delete_null_pointer_checks | |
3828 && POINTER_TYPE_P (TREE_TYPE (op)) | |
3829 && gimple_code (stmt) != GIMPLE_ASM) | |
3830 { | |
3831 unsigned num_uses, num_loads, num_stores; | |
3832 | |
3833 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores); | |
3834 if (num_loads + num_stores > 0) | |
3835 { | |
3836 *val_p = build_int_cst (TREE_TYPE (op), 0); | |
3837 *comp_code_p = NE_EXPR; | |
3838 return true; | |
3839 } | |
3840 } | |
3841 | |
3842 return false; | |
3843 } | |
3844 | |
3845 | |
3846 void dump_asserts_for (FILE *, tree); | |
3847 void debug_asserts_for (tree); | |
3848 void dump_all_asserts (FILE *); | |
3849 void debug_all_asserts (void); | |
3850 | |
3851 /* Dump all the registered assertions for NAME to FILE. */ | |
3852 | |
3853 void | |
3854 dump_asserts_for (FILE *file, tree name) | |
3855 { | |
3856 assert_locus_t loc; | |
3857 | |
3858 fprintf (file, "Assertions to be inserted for "); | |
3859 print_generic_expr (file, name, 0); | |
3860 fprintf (file, "\n"); | |
3861 | |
3862 loc = asserts_for[SSA_NAME_VERSION (name)]; | |
3863 while (loc) | |
3864 { | |
3865 fprintf (file, "\t"); | |
3866 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0); | |
3867 fprintf (file, "\n\tBB #%d", loc->bb->index); | |
3868 if (loc->e) | |
3869 { | |
3870 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index, | |
3871 loc->e->dest->index); | |
3872 dump_edge_info (file, loc->e, 0); | |
3873 } | |
3874 fprintf (file, "\n\tPREDICATE: "); | |
3875 print_generic_expr (file, name, 0); | |
3876 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]); | |
3877 print_generic_expr (file, loc->val, 0); | |
3878 fprintf (file, "\n\n"); | |
3879 loc = loc->next; | |
3880 } | |
3881 | |
3882 fprintf (file, "\n"); | |
3883 } | |
3884 | |
3885 | |
3886 /* Dump all the registered assertions for NAME to stderr. */ | |
3887 | |
3888 void | |
3889 debug_asserts_for (tree name) | |
3890 { | |
3891 dump_asserts_for (stderr, name); | |
3892 } | |
3893 | |
3894 | |
3895 /* Dump all the registered assertions for all the names to FILE. */ | |
3896 | |
3897 void | |
3898 dump_all_asserts (FILE *file) | |
3899 { | |
3900 unsigned i; | |
3901 bitmap_iterator bi; | |
3902 | |
3903 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n"); | |
3904 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi) | |
3905 dump_asserts_for (file, ssa_name (i)); | |
3906 fprintf (file, "\n"); | |
3907 } | |
3908 | |
3909 | |
3910 /* Dump all the registered assertions for all the names to stderr. */ | |
3911 | |
3912 void | |
3913 debug_all_asserts (void) | |
3914 { | |
3915 dump_all_asserts (stderr); | |
3916 } | |
3917 | |
3918 | |
3919 /* If NAME doesn't have an ASSERT_EXPR registered for asserting | |
3920 'EXPR COMP_CODE VAL' at a location that dominates block BB or | |
3921 E->DEST, then register this location as a possible insertion point | |
3922 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>. | |
3923 | |
3924 BB, E and SI provide the exact insertion point for the new | |
3925 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted | |
3926 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on | |
3927 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E | |
3928 must not be NULL. */ | |
3929 | |
3930 static void | |
3931 register_new_assert_for (tree name, tree expr, | |
3932 enum tree_code comp_code, | |
3933 tree val, | |
3934 basic_block bb, | |
3935 edge e, | |
3936 gimple_stmt_iterator si) | |
3937 { | |
3938 assert_locus_t n, loc, last_loc; | |
3939 bool found; | |
3940 basic_block dest_bb; | |
3941 | |
3942 #if defined ENABLE_CHECKING | |
3943 gcc_assert (bb == NULL || e == NULL); | |
3944 | |
3945 if (e == NULL) | |
3946 gcc_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND | |
3947 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH); | |
3948 #endif | |
3949 | |
3950 /* Never build an assert comparing against an integer constant with | |
3951 TREE_OVERFLOW set. This confuses our undefined overflow warning | |
3952 machinery. */ | |
3953 if (TREE_CODE (val) == INTEGER_CST | |
3954 && TREE_OVERFLOW (val)) | |
3955 val = build_int_cst_wide (TREE_TYPE (val), | |
3956 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val)); | |
3957 | |
3958 /* The new assertion A will be inserted at BB or E. We need to | |
3959 determine if the new location is dominated by a previously | |
3960 registered location for A. If we are doing an edge insertion, | |
3961 assume that A will be inserted at E->DEST. Note that this is not | |
3962 necessarily true. | |
3963 | |
3964 If E is a critical edge, it will be split. But even if E is | |
3965 split, the new block will dominate the same set of blocks that | |
3966 E->DEST dominates. | |
3967 | |
3968 The reverse, however, is not true, blocks dominated by E->DEST | |
3969 will not be dominated by the new block created to split E. So, | |
3970 if the insertion location is on a critical edge, we will not use | |
3971 the new location to move another assertion previously registered | |
3972 at a block dominated by E->DEST. */ | |
3973 dest_bb = (bb) ? bb : e->dest; | |
3974 | |
3975 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and | |
3976 VAL at a block dominating DEST_BB, then we don't need to insert a new | |
3977 one. Similarly, if the same assertion already exists at a block | |
3978 dominated by DEST_BB and the new location is not on a critical | |
3979 edge, then update the existing location for the assertion (i.e., | |
3980 move the assertion up in the dominance tree). | |
3981 | |
3982 Note, this is implemented as a simple linked list because there | |
3983 should not be more than a handful of assertions registered per | |
3984 name. If this becomes a performance problem, a table hashed by | |
3985 COMP_CODE and VAL could be implemented. */ | |
3986 loc = asserts_for[SSA_NAME_VERSION (name)]; | |
3987 last_loc = loc; | |
3988 found = false; | |
3989 while (loc) | |
3990 { | |
3991 if (loc->comp_code == comp_code | |
3992 && (loc->val == val | |
3993 || operand_equal_p (loc->val, val, 0)) | |
3994 && (loc->expr == expr | |
3995 || operand_equal_p (loc->expr, expr, 0))) | |
3996 { | |
3997 /* If the assertion NAME COMP_CODE VAL has already been | |
3998 registered at a basic block that dominates DEST_BB, then | |
3999 we don't need to insert the same assertion again. Note | |
4000 that we don't check strict dominance here to avoid | |
4001 replicating the same assertion inside the same basic | |
4002 block more than once (e.g., when a pointer is | |
4003 dereferenced several times inside a block). | |
4004 | |
4005 An exception to this rule are edge insertions. If the | |
4006 new assertion is to be inserted on edge E, then it will | |
4007 dominate all the other insertions that we may want to | |
4008 insert in DEST_BB. So, if we are doing an edge | |
4009 insertion, don't do this dominance check. */ | |
4010 if (e == NULL | |
4011 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb)) | |
4012 return; | |
4013 | |
4014 /* Otherwise, if E is not a critical edge and DEST_BB | |
4015 dominates the existing location for the assertion, move | |
4016 the assertion up in the dominance tree by updating its | |
4017 location information. */ | |
4018 if ((e == NULL || !EDGE_CRITICAL_P (e)) | |
4019 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb)) | |
4020 { | |
4021 loc->bb = dest_bb; | |
4022 loc->e = e; | |
4023 loc->si = si; | |
4024 return; | |
4025 } | |
4026 } | |
4027 | |
4028 /* Update the last node of the list and move to the next one. */ | |
4029 last_loc = loc; | |
4030 loc = loc->next; | |
4031 } | |
4032 | |
4033 /* If we didn't find an assertion already registered for | |
4034 NAME COMP_CODE VAL, add a new one at the end of the list of | |
4035 assertions associated with NAME. */ | |
4036 n = XNEW (struct assert_locus_d); | |
4037 n->bb = dest_bb; | |
4038 n->e = e; | |
4039 n->si = si; | |
4040 n->comp_code = comp_code; | |
4041 n->val = val; | |
4042 n->expr = expr; | |
4043 n->next = NULL; | |
4044 | |
4045 if (last_loc) | |
4046 last_loc->next = n; | |
4047 else | |
4048 asserts_for[SSA_NAME_VERSION (name)] = n; | |
4049 | |
4050 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name)); | |
4051 } | |
4052 | |
4053 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME. | |
4054 Extract a suitable test code and value and store them into *CODE_P and | |
4055 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P. | |
4056 | |
4057 If no extraction was possible, return FALSE, otherwise return TRUE. | |
4058 | |
4059 If INVERT is true, then we invert the result stored into *CODE_P. */ | |
4060 | |
4061 static bool | |
4062 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code, | |
4063 tree cond_op0, tree cond_op1, | |
4064 bool invert, enum tree_code *code_p, | |
4065 tree *val_p) | |
4066 { | |
4067 enum tree_code comp_code; | |
4068 tree val; | |
4069 | |
4070 /* Otherwise, we have a comparison of the form NAME COMP VAL | |
4071 or VAL COMP NAME. */ | |
4072 if (name == cond_op1) | |
4073 { | |
4074 /* If the predicate is of the form VAL COMP NAME, flip | |
4075 COMP around because we need to register NAME as the | |
4076 first operand in the predicate. */ | |
4077 comp_code = swap_tree_comparison (cond_code); | |
4078 val = cond_op0; | |
4079 } | |
4080 else | |
4081 { | |
4082 /* The comparison is of the form NAME COMP VAL, so the | |
4083 comparison code remains unchanged. */ | |
4084 comp_code = cond_code; | |
4085 val = cond_op1; | |
4086 } | |
4087 | |
4088 /* Invert the comparison code as necessary. */ | |
4089 if (invert) | |
4090 comp_code = invert_tree_comparison (comp_code, 0); | |
4091 | |
4092 /* VRP does not handle float types. */ | |
4093 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val))) | |
4094 return false; | |
4095 | |
4096 /* Do not register always-false predicates. | |
4097 FIXME: this works around a limitation in fold() when dealing with | |
4098 enumerations. Given 'enum { N1, N2 } x;', fold will not | |
4099 fold 'if (x > N2)' to 'if (0)'. */ | |
4100 if ((comp_code == GT_EXPR || comp_code == LT_EXPR) | |
4101 && INTEGRAL_TYPE_P (TREE_TYPE (val))) | |
4102 { | |
4103 tree min = TYPE_MIN_VALUE (TREE_TYPE (val)); | |
4104 tree max = TYPE_MAX_VALUE (TREE_TYPE (val)); | |
4105 | |
4106 if (comp_code == GT_EXPR | |
4107 && (!max | |
4108 || compare_values (val, max) == 0)) | |
4109 return false; | |
4110 | |
4111 if (comp_code == LT_EXPR | |
4112 && (!min | |
4113 || compare_values (val, min) == 0)) | |
4114 return false; | |
4115 } | |
4116 *code_p = comp_code; | |
4117 *val_p = val; | |
4118 return true; | |
4119 } | |
4120 | |
4121 /* Try to register an edge assertion for SSA name NAME on edge E for | |
4122 the condition COND contributing to the conditional jump pointed to by BSI. | |
4123 Invert the condition COND if INVERT is true. | |
4124 Return true if an assertion for NAME could be registered. */ | |
4125 | |
4126 static bool | |
4127 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi, | |
4128 enum tree_code cond_code, | |
4129 tree cond_op0, tree cond_op1, bool invert) | |
4130 { | |
4131 tree val; | |
4132 enum tree_code comp_code; | |
4133 bool retval = false; | |
4134 | |
4135 if (!extract_code_and_val_from_cond_with_ops (name, cond_code, | |
4136 cond_op0, | |
4137 cond_op1, | |
4138 invert, &comp_code, &val)) | |
4139 return false; | |
4140 | |
4141 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph | |
4142 reachable from E. */ | |
4143 if (live_on_edge (e, name) | |
4144 && !has_single_use (name)) | |
4145 { | |
4146 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi); | |
4147 retval = true; | |
4148 } | |
4149 | |
4150 /* In the case of NAME <= CST and NAME being defined as | |
4151 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2 | |
4152 and NAME2 <= CST - CST2. We can do the same for NAME > CST. | |
4153 This catches range and anti-range tests. */ | |
4154 if ((comp_code == LE_EXPR | |
4155 || comp_code == GT_EXPR) | |
4156 && TREE_CODE (val) == INTEGER_CST | |
4157 && TYPE_UNSIGNED (TREE_TYPE (val))) | |
4158 { | |
4159 gimple def_stmt = SSA_NAME_DEF_STMT (name); | |
4160 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE; | |
4161 | |
4162 /* Extract CST2 from the (optional) addition. */ | |
4163 if (is_gimple_assign (def_stmt) | |
4164 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR) | |
4165 { | |
4166 name2 = gimple_assign_rhs1 (def_stmt); | |
4167 cst2 = gimple_assign_rhs2 (def_stmt); | |
4168 if (TREE_CODE (name2) == SSA_NAME | |
4169 && TREE_CODE (cst2) == INTEGER_CST) | |
4170 def_stmt = SSA_NAME_DEF_STMT (name2); | |
4171 } | |
4172 | |
4173 /* Extract NAME2 from the (optional) sign-changing cast. */ | |
4174 if (gimple_assign_cast_p (def_stmt)) | |
4175 { | |
4176 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)) | |
4177 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt))) | |
4178 && (TYPE_PRECISION (gimple_expr_type (def_stmt)) | |
4179 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))) | |
4180 name3 = gimple_assign_rhs1 (def_stmt); | |
4181 } | |
4182 | |
4183 /* If name3 is used later, create an ASSERT_EXPR for it. */ | |
4184 if (name3 != NULL_TREE | |
4185 && TREE_CODE (name3) == SSA_NAME | |
4186 && (cst2 == NULL_TREE | |
4187 || TREE_CODE (cst2) == INTEGER_CST) | |
4188 && INTEGRAL_TYPE_P (TREE_TYPE (name3)) | |
4189 && live_on_edge (e, name3) | |
4190 && !has_single_use (name3)) | |
4191 { | |
4192 tree tmp; | |
4193 | |
4194 /* Build an expression for the range test. */ | |
4195 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3); | |
4196 if (cst2 != NULL_TREE) | |
4197 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2); | |
4198 | |
4199 if (dump_file) | |
4200 { | |
4201 fprintf (dump_file, "Adding assert for "); | |
4202 print_generic_expr (dump_file, name3, 0); | |
4203 fprintf (dump_file, " from "); | |
4204 print_generic_expr (dump_file, tmp, 0); | |
4205 fprintf (dump_file, "\n"); | |
4206 } | |
4207 | |
4208 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi); | |
4209 | |
4210 retval = true; | |
4211 } | |
4212 | |
4213 /* If name2 is used later, create an ASSERT_EXPR for it. */ | |
4214 if (name2 != NULL_TREE | |
4215 && TREE_CODE (name2) == SSA_NAME | |
4216 && TREE_CODE (cst2) == INTEGER_CST | |
4217 && INTEGRAL_TYPE_P (TREE_TYPE (name2)) | |
4218 && live_on_edge (e, name2) | |
4219 && !has_single_use (name2)) | |
4220 { | |
4221 tree tmp; | |
4222 | |
4223 /* Build an expression for the range test. */ | |
4224 tmp = name2; | |
4225 if (TREE_TYPE (name) != TREE_TYPE (name2)) | |
4226 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp); | |
4227 if (cst2 != NULL_TREE) | |
4228 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2); | |
4229 | |
4230 if (dump_file) | |
4231 { | |
4232 fprintf (dump_file, "Adding assert for "); | |
4233 print_generic_expr (dump_file, name2, 0); | |
4234 fprintf (dump_file, " from "); | |
4235 print_generic_expr (dump_file, tmp, 0); | |
4236 fprintf (dump_file, "\n"); | |
4237 } | |
4238 | |
4239 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi); | |
4240 | |
4241 retval = true; | |
4242 } | |
4243 } | |
4244 | |
4245 return retval; | |
4246 } | |
4247 | |
4248 /* OP is an operand of a truth value expression which is known to have | |
4249 a particular value. Register any asserts for OP and for any | |
4250 operands in OP's defining statement. | |
4251 | |
4252 If CODE is EQ_EXPR, then we want to register OP is zero (false), | |
4253 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */ | |
4254 | |
4255 static bool | |
4256 register_edge_assert_for_1 (tree op, enum tree_code code, | |
4257 edge e, gimple_stmt_iterator bsi) | |
4258 { | |
4259 bool retval = false; | |
4260 gimple op_def; | |
4261 tree val; | |
4262 enum tree_code rhs_code; | |
4263 | |
4264 /* We only care about SSA_NAMEs. */ | |
4265 if (TREE_CODE (op) != SSA_NAME) | |
4266 return false; | |
4267 | |
4268 /* We know that OP will have a zero or nonzero value. If OP is used | |
4269 more than once go ahead and register an assert for OP. | |
4270 | |
4271 The FOUND_IN_SUBGRAPH support is not helpful in this situation as | |
4272 it will always be set for OP (because OP is used in a COND_EXPR in | |
4273 the subgraph). */ | |
4274 if (!has_single_use (op)) | |
4275 { | |
4276 val = build_int_cst (TREE_TYPE (op), 0); | |
4277 register_new_assert_for (op, op, code, val, NULL, e, bsi); | |
4278 retval = true; | |
4279 } | |
4280 | |
4281 /* Now look at how OP is set. If it's set from a comparison, | |
4282 a truth operation or some bit operations, then we may be able | |
4283 to register information about the operands of that assignment. */ | |
4284 op_def = SSA_NAME_DEF_STMT (op); | |
4285 if (gimple_code (op_def) != GIMPLE_ASSIGN) | |
4286 return retval; | |
4287 | |
4288 rhs_code = gimple_assign_rhs_code (op_def); | |
4289 | |
4290 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison) | |
4291 { | |
4292 bool invert = (code == EQ_EXPR ? true : false); | |
4293 tree op0 = gimple_assign_rhs1 (op_def); | |
4294 tree op1 = gimple_assign_rhs2 (op_def); | |
4295 | |
4296 if (TREE_CODE (op0) == SSA_NAME) | |
4297 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1, | |
4298 invert); | |
4299 if (TREE_CODE (op1) == SSA_NAME) | |
4300 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1, | |
4301 invert); | |
4302 } | |
4303 else if ((code == NE_EXPR | |
4304 && (gimple_assign_rhs_code (op_def) == TRUTH_AND_EXPR | |
4305 || gimple_assign_rhs_code (op_def) == BIT_AND_EXPR)) | |
4306 || (code == EQ_EXPR | |
4307 && (gimple_assign_rhs_code (op_def) == TRUTH_OR_EXPR | |
4308 || gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR))) | |
4309 { | |
4310 /* Recurse on each operand. */ | |
4311 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def), | |
4312 code, e, bsi); | |
4313 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def), | |
4314 code, e, bsi); | |
4315 } | |
4316 else if (gimple_assign_rhs_code (op_def) == TRUTH_NOT_EXPR) | |
4317 { | |
4318 /* Recurse, flipping CODE. */ | |
4319 code = invert_tree_comparison (code, false); | |
4320 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def), | |
4321 code, e, bsi); | |
4322 } | |
4323 else if (gimple_assign_rhs_code (op_def) == SSA_NAME) | |
4324 { | |
4325 /* Recurse through the copy. */ | |
4326 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def), | |
4327 code, e, bsi); | |
4328 } | |
4329 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def))) | |
4330 { | |
4331 /* Recurse through the type conversion. */ | |
4332 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def), | |
4333 code, e, bsi); | |
4334 } | |
4335 | |
4336 return retval; | |
4337 } | |
4338 | |
4339 /* Try to register an edge assertion for SSA name NAME on edge E for | |
4340 the condition COND contributing to the conditional jump pointed to by SI. | |
4341 Return true if an assertion for NAME could be registered. */ | |
4342 | |
4343 static bool | |
4344 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si, | |
4345 enum tree_code cond_code, tree cond_op0, | |
4346 tree cond_op1) | |
4347 { | |
4348 tree val; | |
4349 enum tree_code comp_code; | |
4350 bool retval = false; | |
4351 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0; | |
4352 | |
4353 /* Do not attempt to infer anything in names that flow through | |
4354 abnormal edges. */ | |
4355 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name)) | |
4356 return false; | |
4357 | |
4358 if (!extract_code_and_val_from_cond_with_ops (name, cond_code, | |
4359 cond_op0, cond_op1, | |
4360 is_else_edge, | |
4361 &comp_code, &val)) | |
4362 return false; | |
4363 | |
4364 /* Register ASSERT_EXPRs for name. */ | |
4365 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0, | |
4366 cond_op1, is_else_edge); | |
4367 | |
4368 | |
4369 /* If COND is effectively an equality test of an SSA_NAME against | |
4370 the value zero or one, then we may be able to assert values | |
4371 for SSA_NAMEs which flow into COND. */ | |
4372 | |
4373 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining | |
4374 statement of NAME we can assert both operands of the TRUTH_AND_EXPR | |
4375 have nonzero value. */ | |
4376 if (((comp_code == EQ_EXPR && integer_onep (val)) | |
4377 || (comp_code == NE_EXPR && integer_zerop (val)))) | |
4378 { | |
4379 gimple def_stmt = SSA_NAME_DEF_STMT (name); | |
4380 | |
4381 if (is_gimple_assign (def_stmt) | |
4382 && (gimple_assign_rhs_code (def_stmt) == TRUTH_AND_EXPR | |
4383 || gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR)) | |
4384 { | |
4385 tree op0 = gimple_assign_rhs1 (def_stmt); | |
4386 tree op1 = gimple_assign_rhs2 (def_stmt); | |
4387 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si); | |
4388 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si); | |
4389 } | |
4390 } | |
4391 | |
4392 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining | |
4393 statement of NAME we can assert both operands of the TRUTH_OR_EXPR | |
4394 have zero value. */ | |
4395 if (((comp_code == EQ_EXPR && integer_zerop (val)) | |
4396 || (comp_code == NE_EXPR && integer_onep (val)))) | |
4397 { | |
4398 gimple def_stmt = SSA_NAME_DEF_STMT (name); | |
4399 | |
4400 if (is_gimple_assign (def_stmt) | |
4401 && (gimple_assign_rhs_code (def_stmt) == TRUTH_OR_EXPR | |
4402 /* For BIT_IOR_EXPR only if NAME == 0 both operands have | |
4403 necessarily zero value. */ | |
4404 || (comp_code == EQ_EXPR | |
4405 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR)))) | |
4406 { | |
4407 tree op0 = gimple_assign_rhs1 (def_stmt); | |
4408 tree op1 = gimple_assign_rhs2 (def_stmt); | |
4409 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si); | |
4410 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si); | |
4411 } | |
4412 } | |
4413 | |
4414 return retval; | |
4415 } | |
4416 | |
4417 | |
4418 /* Determine whether the outgoing edges of BB should receive an | |
4419 ASSERT_EXPR for each of the operands of BB's LAST statement. | |
4420 The last statement of BB must be a COND_EXPR. | |
4421 | |
4422 If any of the sub-graphs rooted at BB have an interesting use of | |
4423 the predicate operands, an assert location node is added to the | |
4424 list of assertions for the corresponding operands. */ | |
4425 | |
4426 static bool | |
4427 find_conditional_asserts (basic_block bb, gimple last) | |
4428 { | |
4429 bool need_assert; | |
4430 gimple_stmt_iterator bsi; | |
4431 tree op; | |
4432 edge_iterator ei; | |
4433 edge e; | |
4434 ssa_op_iter iter; | |
4435 | |
4436 need_assert = false; | |
4437 bsi = gsi_for_stmt (last); | |
4438 | |
4439 /* Look for uses of the operands in each of the sub-graphs | |
4440 rooted at BB. We need to check each of the outgoing edges | |
4441 separately, so that we know what kind of ASSERT_EXPR to | |
4442 insert. */ | |
4443 FOR_EACH_EDGE (e, ei, bb->succs) | |
4444 { | |
4445 if (e->dest == bb) | |
4446 continue; | |
4447 | |
4448 /* Register the necessary assertions for each operand in the | |
4449 conditional predicate. */ | |
4450 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE) | |
4451 { | |
4452 need_assert |= register_edge_assert_for (op, e, bsi, | |
4453 gimple_cond_code (last), | |
4454 gimple_cond_lhs (last), | |
4455 gimple_cond_rhs (last)); | |
4456 } | |
4457 } | |
4458 | |
4459 return need_assert; | |
4460 } | |
4461 | |
4462 /* Compare two case labels sorting first by the destination label uid | |
4463 and then by the case value. */ | |
4464 | |
4465 static int | |
4466 compare_case_labels (const void *p1, const void *p2) | |
4467 { | |
4468 const_tree const case1 = *(const_tree const*)p1; | |
4469 const_tree const case2 = *(const_tree const*)p2; | |
4470 unsigned int uid1 = DECL_UID (CASE_LABEL (case1)); | |
4471 unsigned int uid2 = DECL_UID (CASE_LABEL (case2)); | |
4472 | |
4473 if (uid1 < uid2) | |
4474 return -1; | |
4475 else if (uid1 == uid2) | |
4476 { | |
4477 /* Make sure the default label is first in a group. */ | |
4478 if (!CASE_LOW (case1)) | |
4479 return -1; | |
4480 else if (!CASE_LOW (case2)) | |
4481 return 1; | |
4482 else | |
4483 return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2)); | |
4484 } | |
4485 else | |
4486 return 1; | |
4487 } | |
4488 | |
4489 /* Determine whether the outgoing edges of BB should receive an | |
4490 ASSERT_EXPR for each of the operands of BB's LAST statement. | |
4491 The last statement of BB must be a SWITCH_EXPR. | |
4492 | |
4493 If any of the sub-graphs rooted at BB have an interesting use of | |
4494 the predicate operands, an assert location node is added to the | |
4495 list of assertions for the corresponding operands. */ | |
4496 | |
4497 static bool | |
4498 find_switch_asserts (basic_block bb, gimple last) | |
4499 { | |
4500 bool need_assert; | |
4501 gimple_stmt_iterator bsi; | |
4502 tree op; | |
4503 edge e; | |
4504 tree vec2; | |
4505 size_t n = gimple_switch_num_labels(last); | |
4506 #if GCC_VERSION >= 4000 | |
4507 unsigned int idx; | |
4508 #else | |
4509 /* Work around GCC 3.4 bug (PR 37086). */ | |
4510 volatile unsigned int idx; | |
4511 #endif | |
4512 | |
4513 need_assert = false; | |
4514 bsi = gsi_for_stmt (last); | |
4515 op = gimple_switch_index (last); | |
4516 if (TREE_CODE (op) != SSA_NAME) | |
4517 return false; | |
4518 | |
4519 /* Build a vector of case labels sorted by destination label. */ | |
4520 vec2 = make_tree_vec (n); | |
4521 for (idx = 0; idx < n; ++idx) | |
4522 TREE_VEC_ELT (vec2, idx) = gimple_switch_label (last, idx); | |
4523 qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels); | |
4524 | |
4525 for (idx = 0; idx < n; ++idx) | |
4526 { | |
4527 tree min, max; | |
4528 tree cl = TREE_VEC_ELT (vec2, idx); | |
4529 | |
4530 min = CASE_LOW (cl); | |
4531 max = CASE_HIGH (cl); | |
4532 | |
4533 /* If there are multiple case labels with the same destination | |
4534 we need to combine them to a single value range for the edge. */ | |
4535 if (idx + 1 < n | |
4536 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1))) | |
4537 { | |
4538 /* Skip labels until the last of the group. */ | |
4539 do { | |
4540 ++idx; | |
4541 } while (idx < n | |
4542 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx))); | |
4543 --idx; | |
4544 | |
4545 /* Pick up the maximum of the case label range. */ | |
4546 if (CASE_HIGH (TREE_VEC_ELT (vec2, idx))) | |
4547 max = CASE_HIGH (TREE_VEC_ELT (vec2, idx)); | |
4548 else | |
4549 max = CASE_LOW (TREE_VEC_ELT (vec2, idx)); | |
4550 } | |
4551 | |
4552 /* Nothing to do if the range includes the default label until we | |
4553 can register anti-ranges. */ | |
4554 if (min == NULL_TREE) | |
4555 continue; | |
4556 | |
4557 /* Find the edge to register the assert expr on. */ | |
4558 e = find_edge (bb, label_to_block (CASE_LABEL (cl))); | |
4559 | |
4560 /* Register the necessary assertions for the operand in the | |
4561 SWITCH_EXPR. */ | |
4562 need_assert |= register_edge_assert_for (op, e, bsi, | |
4563 max ? GE_EXPR : EQ_EXPR, | |
4564 op, | |
4565 fold_convert (TREE_TYPE (op), | |
4566 min)); | |
4567 if (max) | |
4568 { | |
4569 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR, | |
4570 op, | |
4571 fold_convert (TREE_TYPE (op), | |
4572 max)); | |
4573 } | |
4574 } | |
4575 | |
4576 return need_assert; | |
4577 } | |
4578 | |
4579 | |
4580 /* Traverse all the statements in block BB looking for statements that | |
4581 may generate useful assertions for the SSA names in their operand. | |
4582 If a statement produces a useful assertion A for name N_i, then the | |
4583 list of assertions already generated for N_i is scanned to | |
4584 determine if A is actually needed. | |
4585 | |
4586 If N_i already had the assertion A at a location dominating the | |
4587 current location, then nothing needs to be done. Otherwise, the | |
4588 new location for A is recorded instead. | |
4589 | |
4590 1- For every statement S in BB, all the variables used by S are | |
4591 added to bitmap FOUND_IN_SUBGRAPH. | |
4592 | |
4593 2- If statement S uses an operand N in a way that exposes a known | |
4594 value range for N, then if N was not already generated by an | |
4595 ASSERT_EXPR, create a new assert location for N. For instance, | |
4596 if N is a pointer and the statement dereferences it, we can | |
4597 assume that N is not NULL. | |
4598 | |
4599 3- COND_EXPRs are a special case of #2. We can derive range | |
4600 information from the predicate but need to insert different | |
4601 ASSERT_EXPRs for each of the sub-graphs rooted at the | |
4602 conditional block. If the last statement of BB is a conditional | |
4603 expression of the form 'X op Y', then | |
4604 | |
4605 a) Remove X and Y from the set FOUND_IN_SUBGRAPH. | |
4606 | |
4607 b) If the conditional is the only entry point to the sub-graph | |
4608 corresponding to the THEN_CLAUSE, recurse into it. On | |
4609 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then | |
4610 an ASSERT_EXPR is added for the corresponding variable. | |
4611 | |
4612 c) Repeat step (b) on the ELSE_CLAUSE. | |
4613 | |
4614 d) Mark X and Y in FOUND_IN_SUBGRAPH. | |
4615 | |
4616 For instance, | |
4617 | |
4618 if (a == 9) | |
4619 b = a; | |
4620 else | |
4621 b = c + 1; | |
4622 | |
4623 In this case, an assertion on the THEN clause is useful to | |
4624 determine that 'a' is always 9 on that edge. However, an assertion | |
4625 on the ELSE clause would be unnecessary. | |
4626 | |
4627 4- If BB does not end in a conditional expression, then we recurse | |
4628 into BB's dominator children. | |
4629 | |
4630 At the end of the recursive traversal, every SSA name will have a | |
4631 list of locations where ASSERT_EXPRs should be added. When a new | |
4632 location for name N is found, it is registered by calling | |
4633 register_new_assert_for. That function keeps track of all the | |
4634 registered assertions to prevent adding unnecessary assertions. | |
4635 For instance, if a pointer P_4 is dereferenced more than once in a | |
4636 dominator tree, only the location dominating all the dereference of | |
4637 P_4 will receive an ASSERT_EXPR. | |
4638 | |
4639 If this function returns true, then it means that there are names | |
4640 for which we need to generate ASSERT_EXPRs. Those assertions are | |
4641 inserted by process_assert_insertions. */ | |
4642 | |
4643 static bool | |
4644 find_assert_locations_1 (basic_block bb, sbitmap live) | |
4645 { | |
4646 gimple_stmt_iterator si; | |
4647 gimple last; | |
4648 gimple phi; | |
4649 bool need_assert; | |
4650 | |
4651 need_assert = false; | |
4652 last = last_stmt (bb); | |
4653 | |
4654 /* If BB's last statement is a conditional statement involving integer | |
4655 operands, determine if we need to add ASSERT_EXPRs. */ | |
4656 if (last | |
4657 && gimple_code (last) == GIMPLE_COND | |
4658 && !fp_predicate (last) | |
4659 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE)) | |
4660 need_assert |= find_conditional_asserts (bb, last); | |
4661 | |
4662 /* If BB's last statement is a switch statement involving integer | |
4663 operands, determine if we need to add ASSERT_EXPRs. */ | |
4664 if (last | |
4665 && gimple_code (last) == GIMPLE_SWITCH | |
4666 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE)) | |
4667 need_assert |= find_switch_asserts (bb, last); | |
4668 | |
4669 /* Traverse all the statements in BB marking used names and looking | |
4670 for statements that may infer assertions for their used operands. */ | |
4671 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) | |
4672 { | |
4673 gimple stmt; | |
4674 tree op; | |
4675 ssa_op_iter i; | |
4676 | |
4677 stmt = gsi_stmt (si); | |
4678 | |
4679 /* See if we can derive an assertion for any of STMT's operands. */ | |
4680 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE) | |
4681 { | |
4682 tree value; | |
4683 enum tree_code comp_code; | |
4684 | |
4685 /* Mark OP in our live bitmap. */ | |
4686 SET_BIT (live, SSA_NAME_VERSION (op)); | |
4687 | |
4688 /* If OP is used in such a way that we can infer a value | |
4689 range for it, and we don't find a previous assertion for | |
4690 it, create a new assertion location node for OP. */ | |
4691 if (infer_value_range (stmt, op, &comp_code, &value)) | |
4692 { | |
4693 /* If we are able to infer a nonzero value range for OP, | |
4694 then walk backwards through the use-def chain to see if OP | |
4695 was set via a typecast. | |
4696 | |
4697 If so, then we can also infer a nonzero value range | |
4698 for the operand of the NOP_EXPR. */ | |
4699 if (comp_code == NE_EXPR && integer_zerop (value)) | |
4700 { | |
4701 tree t = op; | |
4702 gimple def_stmt = SSA_NAME_DEF_STMT (t); | |
4703 | |
4704 while (is_gimple_assign (def_stmt) | |
4705 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR | |
4706 && TREE_CODE | |
4707 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME | |
4708 && POINTER_TYPE_P | |
4709 (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))) | |
4710 { | |
4711 t = gimple_assign_rhs1 (def_stmt); | |
4712 def_stmt = SSA_NAME_DEF_STMT (t); | |
4713 | |
4714 /* Note we want to register the assert for the | |
4715 operand of the NOP_EXPR after SI, not after the | |
4716 conversion. */ | |
4717 if (! has_single_use (t)) | |
4718 { | |
4719 register_new_assert_for (t, t, comp_code, value, | |
4720 bb, NULL, si); | |
4721 need_assert = true; | |
4722 } | |
4723 } | |
4724 } | |
4725 | |
4726 /* If OP is used only once, namely in this STMT, don't | |
4727 bother creating an ASSERT_EXPR for it. Such an | |
4728 ASSERT_EXPR would do nothing but increase compile time. */ | |
4729 if (!has_single_use (op)) | |
4730 { | |
4731 register_new_assert_for (op, op, comp_code, value, | |
4732 bb, NULL, si); | |
4733 need_assert = true; | |
4734 } | |
4735 } | |
4736 } | |
4737 } | |
4738 | |
4739 /* Traverse all PHI nodes in BB marking used operands. */ | |
4740 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si)) | |
4741 { | |
4742 use_operand_p arg_p; | |
4743 ssa_op_iter i; | |
4744 phi = gsi_stmt (si); | |
4745 | |
4746 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE) | |
4747 { | |
4748 tree arg = USE_FROM_PTR (arg_p); | |
4749 if (TREE_CODE (arg) == SSA_NAME) | |
4750 SET_BIT (live, SSA_NAME_VERSION (arg)); | |
4751 } | |
4752 } | |
4753 | |
4754 return need_assert; | |
4755 } | |
4756 | |
4757 /* Do an RPO walk over the function computing SSA name liveness | |
4758 on-the-fly and deciding on assert expressions to insert. | |
4759 Returns true if there are assert expressions to be inserted. */ | |
4760 | |
4761 static bool | |
4762 find_assert_locations (void) | |
4763 { | |
4764 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS); | |
4765 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS); | |
4766 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS); | |
4767 int rpo_cnt, i; | |
4768 bool need_asserts; | |
4769 | |
4770 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS); | |
4771 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false); | |
4772 for (i = 0; i < rpo_cnt; ++i) | |
4773 bb_rpo[rpo[i]] = i; | |
4774 | |
4775 need_asserts = false; | |
4776 for (i = rpo_cnt-1; i >= 0; --i) | |
4777 { | |
4778 basic_block bb = BASIC_BLOCK (rpo[i]); | |
4779 edge e; | |
4780 edge_iterator ei; | |
4781 | |
4782 if (!live[rpo[i]]) | |
4783 { | |
4784 live[rpo[i]] = sbitmap_alloc (num_ssa_names); | |
4785 sbitmap_zero (live[rpo[i]]); | |
4786 } | |
4787 | |
4788 /* Process BB and update the live information with uses in | |
4789 this block. */ | |
4790 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]); | |
4791 | |
4792 /* Merge liveness into the predecessor blocks and free it. */ | |
4793 if (!sbitmap_empty_p (live[rpo[i]])) | |
4794 { | |
4795 int pred_rpo = i; | |
4796 FOR_EACH_EDGE (e, ei, bb->preds) | |
4797 { | |
4798 int pred = e->src->index; | |
4799 if (e->flags & EDGE_DFS_BACK) | |
4800 continue; | |
4801 | |
4802 if (!live[pred]) | |
4803 { | |
4804 live[pred] = sbitmap_alloc (num_ssa_names); | |
4805 sbitmap_zero (live[pred]); | |
4806 } | |
4807 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]); | |
4808 | |
4809 if (bb_rpo[pred] < pred_rpo) | |
4810 pred_rpo = bb_rpo[pred]; | |
4811 } | |
4812 | |
4813 /* Record the RPO number of the last visited block that needs | |
4814 live information from this block. */ | |
4815 last_rpo[rpo[i]] = pred_rpo; | |
4816 } | |
4817 else | |
4818 { | |
4819 sbitmap_free (live[rpo[i]]); | |
4820 live[rpo[i]] = NULL; | |
4821 } | |
4822 | |
4823 /* We can free all successors live bitmaps if all their | |
4824 predecessors have been visited already. */ | |
4825 FOR_EACH_EDGE (e, ei, bb->succs) | |
4826 if (last_rpo[e->dest->index] == i | |
4827 && live[e->dest->index]) | |
4828 { | |
4829 sbitmap_free (live[e->dest->index]); | |
4830 live[e->dest->index] = NULL; | |
4831 } | |
4832 } | |
4833 | |
4834 XDELETEVEC (rpo); | |
4835 XDELETEVEC (bb_rpo); | |
4836 XDELETEVEC (last_rpo); | |
4837 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i) | |
4838 if (live[i]) | |
4839 sbitmap_free (live[i]); | |
4840 XDELETEVEC (live); | |
4841 | |
4842 return need_asserts; | |
4843 } | |
4844 | |
4845 /* Create an ASSERT_EXPR for NAME and insert it in the location | |
4846 indicated by LOC. Return true if we made any edge insertions. */ | |
4847 | |
4848 static bool | |
4849 process_assert_insertions_for (tree name, assert_locus_t loc) | |
4850 { | |
4851 /* Build the comparison expression NAME_i COMP_CODE VAL. */ | |
4852 gimple stmt; | |
4853 tree cond; | |
4854 gimple assert_stmt; | |
4855 edge_iterator ei; | |
4856 edge e; | |
4857 | |
4858 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val); | |
4859 assert_stmt = build_assert_expr_for (cond, name); | |
4860 if (loc->e) | |
4861 { | |
4862 /* We have been asked to insert the assertion on an edge. This | |
4863 is used only by COND_EXPR and SWITCH_EXPR assertions. */ | |
4864 #if defined ENABLE_CHECKING | |
4865 gcc_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND | |
4866 || gimple_code (gsi_stmt (loc->si)) == GIMPLE_SWITCH); | |
4867 #endif | |
4868 | |
4869 gsi_insert_on_edge (loc->e, assert_stmt); | |
4870 return true; | |
4871 } | |
4872 | |
4873 /* Otherwise, we can insert right after LOC->SI iff the | |
4874 statement must not be the last statement in the block. */ | |
4875 stmt = gsi_stmt (loc->si); | |
4876 if (!stmt_ends_bb_p (stmt)) | |
4877 { | |
4878 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT); | |
4879 return false; | |
4880 } | |
4881 | |
4882 /* If STMT must be the last statement in BB, we can only insert new | |
4883 assertions on the non-abnormal edge out of BB. Note that since | |
4884 STMT is not control flow, there may only be one non-abnormal edge | |
4885 out of BB. */ | |
4886 FOR_EACH_EDGE (e, ei, loc->bb->succs) | |
4887 if (!(e->flags & EDGE_ABNORMAL)) | |
4888 { | |
4889 gsi_insert_on_edge (e, assert_stmt); | |
4890 return true; | |
4891 } | |
4892 | |
4893 gcc_unreachable (); | |
4894 } | |
4895 | |
4896 | |
4897 /* Process all the insertions registered for every name N_i registered | |
4898 in NEED_ASSERT_FOR. The list of assertions to be inserted are | |
4899 found in ASSERTS_FOR[i]. */ | |
4900 | |
4901 static void | |
4902 process_assert_insertions (void) | |
4903 { | |
4904 unsigned i; | |
4905 bitmap_iterator bi; | |
4906 bool update_edges_p = false; | |
4907 int num_asserts = 0; | |
4908 | |
4909 if (dump_file && (dump_flags & TDF_DETAILS)) | |
4910 dump_all_asserts (dump_file); | |
4911 | |
4912 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi) | |
4913 { | |
4914 assert_locus_t loc = asserts_for[i]; | |
4915 gcc_assert (loc); | |
4916 | |
4917 while (loc) | |
4918 { | |
4919 assert_locus_t next = loc->next; | |
4920 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc); | |
4921 free (loc); | |
4922 loc = next; | |
4923 num_asserts++; | |
4924 } | |
4925 } | |
4926 | |
4927 if (update_edges_p) | |
4928 gsi_commit_edge_inserts (); | |
4929 | |
4930 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted", | |
4931 num_asserts); | |
4932 } | |
4933 | |
4934 | |
4935 /* Traverse the flowgraph looking for conditional jumps to insert range | |
4936 expressions. These range expressions are meant to provide information | |
4937 to optimizations that need to reason in terms of value ranges. They | |
4938 will not be expanded into RTL. For instance, given: | |
4939 | |
4940 x = ... | |
4941 y = ... | |
4942 if (x < y) | |
4943 y = x - 2; | |
4944 else | |
4945 x = y + 3; | |
4946 | |
4947 this pass will transform the code into: | |
4948 | |
4949 x = ... | |
4950 y = ... | |
4951 if (x < y) | |
4952 { | |
4953 x = ASSERT_EXPR <x, x < y> | |
4954 y = x - 2 | |
4955 } | |
4956 else | |
4957 { | |
4958 y = ASSERT_EXPR <y, x <= y> | |
4959 x = y + 3 | |
4960 } | |
4961 | |
4962 The idea is that once copy and constant propagation have run, other | |
4963 optimizations will be able to determine what ranges of values can 'x' | |
4964 take in different paths of the code, simply by checking the reaching | |
4965 definition of 'x'. */ | |
4966 | |
4967 static void | |
4968 insert_range_assertions (void) | |
4969 { | |
4970 need_assert_for = BITMAP_ALLOC (NULL); | |
4971 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names); | |
4972 | |
4973 calculate_dominance_info (CDI_DOMINATORS); | |
4974 | |
4975 if (find_assert_locations ()) | |
4976 { | |
4977 process_assert_insertions (); | |
4978 update_ssa (TODO_update_ssa_no_phi); | |
4979 } | |
4980 | |
4981 if (dump_file && (dump_flags & TDF_DETAILS)) | |
4982 { | |
4983 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n"); | |
4984 dump_function_to_file (current_function_decl, dump_file, dump_flags); | |
4985 } | |
4986 | |
4987 free (asserts_for); | |
4988 BITMAP_FREE (need_assert_for); | |
4989 } | |
4990 | |
4991 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays | |
4992 and "struct" hacks. If VRP can determine that the | |
4993 array subscript is a constant, check if it is outside valid | |
4994 range. If the array subscript is a RANGE, warn if it is | |
4995 non-overlapping with valid range. | |
4996 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */ | |
4997 | |
4998 static void | |
4999 check_array_ref (tree ref, const location_t *location, bool ignore_off_by_one) | |
5000 { | |
5001 value_range_t* vr = NULL; | |
5002 tree low_sub, up_sub; | |
5003 tree low_bound, up_bound = array_ref_up_bound (ref); | |
5004 | |
5005 low_sub = up_sub = TREE_OPERAND (ref, 1); | |
5006 | |
5007 if (!up_bound || TREE_NO_WARNING (ref) | |
5008 || TREE_CODE (up_bound) != INTEGER_CST | |
5009 /* Can not check flexible arrays. */ | |
5010 || (TYPE_SIZE (TREE_TYPE (ref)) == NULL_TREE | |
5011 && TYPE_DOMAIN (TREE_TYPE (ref)) != NULL_TREE | |
5012 && TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (ref))) == NULL_TREE) | |
5013 /* Accesses after the end of arrays of size 0 (gcc | |
5014 extension) and 1 are likely intentional ("struct | |
5015 hack"). */ | |
5016 || compare_tree_int (up_bound, 1) <= 0) | |
5017 return; | |
5018 | |
5019 low_bound = array_ref_low_bound (ref); | |
5020 | |
5021 if (TREE_CODE (low_sub) == SSA_NAME) | |
5022 { | |
5023 vr = get_value_range (low_sub); | |
5024 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE) | |
5025 { | |
5026 low_sub = vr->type == VR_RANGE ? vr->max : vr->min; | |
5027 up_sub = vr->type == VR_RANGE ? vr->min : vr->max; | |
5028 } | |
5029 } | |
5030 | |
5031 if (vr && vr->type == VR_ANTI_RANGE) | |
5032 { | |
5033 if (TREE_CODE (up_sub) == INTEGER_CST | |
5034 && tree_int_cst_lt (up_bound, up_sub) | |
5035 && TREE_CODE (low_sub) == INTEGER_CST | |
5036 && tree_int_cst_lt (low_sub, low_bound)) | |
5037 { | |
5038 warning (OPT_Warray_bounds, | |
5039 "%Harray subscript is outside array bounds", location); | |
5040 TREE_NO_WARNING (ref) = 1; | |
5041 } | |
5042 } | |
5043 else if (TREE_CODE (up_sub) == INTEGER_CST | |
5044 && tree_int_cst_lt (up_bound, up_sub) | |
5045 && !tree_int_cst_equal (up_bound, up_sub) | |
5046 && (!ignore_off_by_one | |
5047 || !tree_int_cst_equal (int_const_binop (PLUS_EXPR, | |
5048 up_bound, | |
5049 integer_one_node, | |
5050 0), | |
5051 up_sub))) | |
5052 { | |
5053 warning (OPT_Warray_bounds, "%Harray subscript is above array bounds", | |
5054 location); | |
5055 TREE_NO_WARNING (ref) = 1; | |
5056 } | |
5057 else if (TREE_CODE (low_sub) == INTEGER_CST | |
5058 && tree_int_cst_lt (low_sub, low_bound)) | |
5059 { | |
5060 warning (OPT_Warray_bounds, "%Harray subscript is below array bounds", | |
5061 location); | |
5062 TREE_NO_WARNING (ref) = 1; | |
5063 } | |
5064 } | |
5065 | |
5066 /* Searches if the expr T, located at LOCATION computes | |
5067 address of an ARRAY_REF, and call check_array_ref on it. */ | |
5068 | |
5069 static void | |
5070 search_for_addr_array (tree t, const location_t *location) | |
5071 { | |
5072 while (TREE_CODE (t) == SSA_NAME) | |
5073 { | |
5074 gimple g = SSA_NAME_DEF_STMT (t); | |
5075 | |
5076 if (gimple_code (g) != GIMPLE_ASSIGN) | |
5077 return; | |
5078 | |
5079 if (get_gimple_rhs_class (gimple_assign_rhs_code (g)) | |
5080 != GIMPLE_SINGLE_RHS) | |
5081 return; | |
5082 | |
5083 t = gimple_assign_rhs1 (g); | |
5084 } | |
5085 | |
5086 | |
5087 /* We are only interested in addresses of ARRAY_REF's. */ | |
5088 if (TREE_CODE (t) != ADDR_EXPR) | |
5089 return; | |
5090 | |
5091 /* Check each ARRAY_REFs in the reference chain. */ | |
5092 do | |
5093 { | |
5094 if (TREE_CODE (t) == ARRAY_REF) | |
5095 check_array_ref (t, location, true /*ignore_off_by_one*/); | |
5096 | |
5097 t = TREE_OPERAND (t, 0); | |
5098 } | |
5099 while (handled_component_p (t)); | |
5100 } | |
5101 | |
5102 /* walk_tree() callback that checks if *TP is | |
5103 an ARRAY_REF inside an ADDR_EXPR (in which an array | |
5104 subscript one outside the valid range is allowed). Call | |
5105 check_array_ref for each ARRAY_REF found. The location is | |
5106 passed in DATA. */ | |
5107 | |
5108 static tree | |
5109 check_array_bounds (tree *tp, int *walk_subtree, void *data) | |
5110 { | |
5111 tree t = *tp; | |
5112 struct walk_stmt_info *wi = (struct walk_stmt_info *) data; | |
5113 const location_t *location = (const location_t *) wi->info; | |
5114 | |
5115 *walk_subtree = TRUE; | |
5116 | |
5117 if (TREE_CODE (t) == ARRAY_REF) | |
5118 check_array_ref (t, location, false /*ignore_off_by_one*/); | |
5119 | |
5120 if (TREE_CODE (t) == INDIRECT_REF | |
5121 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0))) | |
5122 search_for_addr_array (TREE_OPERAND (t, 0), location); | |
5123 | |
5124 if (TREE_CODE (t) == ADDR_EXPR) | |
5125 *walk_subtree = FALSE; | |
5126 | |
5127 return NULL_TREE; | |
5128 } | |
5129 | |
5130 /* Walk over all statements of all reachable BBs and call check_array_bounds | |
5131 on them. */ | |
5132 | |
5133 static void | |
5134 check_all_array_refs (void) | |
5135 { | |
5136 basic_block bb; | |
5137 gimple_stmt_iterator si; | |
5138 | |
5139 FOR_EACH_BB (bb) | |
5140 { | |
5141 /* Skip bb's that are clearly unreachable. */ | |
5142 if (single_pred_p (bb)) | |
5143 { | |
5144 basic_block pred_bb = EDGE_PRED (bb, 0)->src; | |
5145 gimple ls = NULL; | |
5146 | |
5147 if (!gsi_end_p (gsi_last_bb (pred_bb))) | |
5148 ls = gsi_stmt (gsi_last_bb (pred_bb)); | |
5149 | |
5150 if (ls && gimple_code (ls) == GIMPLE_COND | |
5151 && ((gimple_cond_false_p (ls) | |
5152 && (EDGE_PRED (bb, 0)->flags & EDGE_TRUE_VALUE)) | |
5153 || (gimple_cond_true_p (ls) | |
5154 && (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE)))) | |
5155 continue; | |
5156 } | |
5157 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) | |
5158 { | |
5159 gimple stmt = gsi_stmt (si); | |
5160 const location_t *location = gimple_location_ptr (stmt); | |
5161 struct walk_stmt_info wi; | |
5162 if (!gimple_has_location (stmt)) | |
5163 continue; | |
5164 | |
5165 if (is_gimple_call (stmt)) | |
5166 { | |
5167 size_t i; | |
5168 size_t n = gimple_call_num_args (stmt); | |
5169 for (i = 0; i < n; i++) | |
5170 { | |
5171 tree arg = gimple_call_arg (stmt, i); | |
5172 search_for_addr_array (arg, location); | |
5173 } | |
5174 } | |
5175 else | |
5176 { | |
5177 memset (&wi, 0, sizeof (wi)); | |
5178 wi.info = CONST_CAST (void *, (const void *) location); | |
5179 | |
5180 walk_gimple_op (gsi_stmt (si), | |
5181 check_array_bounds, | |
5182 &wi); | |
5183 } | |
5184 } | |
5185 } | |
5186 } | |
5187 | |
5188 /* Convert range assertion expressions into the implied copies and | |
5189 copy propagate away the copies. Doing the trivial copy propagation | |
5190 here avoids the need to run the full copy propagation pass after | |
5191 VRP. | |
5192 | |
5193 FIXME, this will eventually lead to copy propagation removing the | |
5194 names that had useful range information attached to them. For | |
5195 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>, | |
5196 then N_i will have the range [3, +INF]. | |
5197 | |
5198 However, by converting the assertion into the implied copy | |
5199 operation N_i = N_j, we will then copy-propagate N_j into the uses | |
5200 of N_i and lose the range information. We may want to hold on to | |
5201 ASSERT_EXPRs a little while longer as the ranges could be used in | |
5202 things like jump threading. | |
5203 | |
5204 The problem with keeping ASSERT_EXPRs around is that passes after | |
5205 VRP need to handle them appropriately. | |
5206 | |
5207 Another approach would be to make the range information a first | |
5208 class property of the SSA_NAME so that it can be queried from | |
5209 any pass. This is made somewhat more complex by the need for | |
5210 multiple ranges to be associated with one SSA_NAME. */ | |
5211 | |
5212 static void | |
5213 remove_range_assertions (void) | |
5214 { | |
5215 basic_block bb; | |
5216 gimple_stmt_iterator si; | |
5217 | |
5218 /* Note that the BSI iterator bump happens at the bottom of the | |
5219 loop and no bump is necessary if we're removing the statement | |
5220 referenced by the current BSI. */ | |
5221 FOR_EACH_BB (bb) | |
5222 for (si = gsi_start_bb (bb); !gsi_end_p (si);) | |
5223 { | |
5224 gimple stmt = gsi_stmt (si); | |
5225 gimple use_stmt; | |
5226 | |
5227 if (is_gimple_assign (stmt) | |
5228 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR) | |
5229 { | |
5230 tree rhs = gimple_assign_rhs1 (stmt); | |
5231 tree var; | |
5232 tree cond = fold (ASSERT_EXPR_COND (rhs)); | |
5233 use_operand_p use_p; | |
5234 imm_use_iterator iter; | |
5235 | |
5236 gcc_assert (cond != boolean_false_node); | |
5237 | |
5238 /* Propagate the RHS into every use of the LHS. */ | |
5239 var = ASSERT_EXPR_VAR (rhs); | |
5240 FOR_EACH_IMM_USE_STMT (use_stmt, iter, | |
5241 gimple_assign_lhs (stmt)) | |
5242 FOR_EACH_IMM_USE_ON_STMT (use_p, iter) | |
5243 { | |
5244 SET_USE (use_p, var); | |
5245 gcc_assert (TREE_CODE (var) == SSA_NAME); | |
5246 } | |
5247 | |
5248 /* And finally, remove the copy, it is not needed. */ | |
5249 gsi_remove (&si, true); | |
5250 release_defs (stmt); | |
5251 } | |
5252 else | |
5253 gsi_next (&si); | |
5254 } | |
5255 } | |
5256 | |
5257 | |
5258 /* Return true if STMT is interesting for VRP. */ | |
5259 | |
5260 static bool | |
5261 stmt_interesting_for_vrp (gimple stmt) | |
5262 { | |
5263 if (gimple_code (stmt) == GIMPLE_PHI | |
5264 && is_gimple_reg (gimple_phi_result (stmt)) | |
5265 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt))) | |
5266 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt))))) | |
5267 return true; | |
5268 else if (is_gimple_assign (stmt) || is_gimple_call (stmt)) | |
5269 { | |
5270 tree lhs = gimple_get_lhs (stmt); | |
5271 | |
5272 /* In general, assignments with virtual operands are not useful | |
5273 for deriving ranges, with the obvious exception of calls to | |
5274 builtin functions. */ | |
5275 if (lhs && TREE_CODE (lhs) == SSA_NAME | |
5276 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs)) | |
5277 || POINTER_TYPE_P (TREE_TYPE (lhs))) | |
5278 && ((is_gimple_call (stmt) | |
5279 && gimple_call_fndecl (stmt) != NULL_TREE | |
5280 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt))) | |
5281 || ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS))) | |
5282 return true; | |
5283 } | |
5284 else if (gimple_code (stmt) == GIMPLE_COND | |
5285 || gimple_code (stmt) == GIMPLE_SWITCH) | |
5286 return true; | |
5287 | |
5288 return false; | |
5289 } | |
5290 | |
5291 | |
5292 /* Initialize local data structures for VRP. */ | |
5293 | |
5294 static void | |
5295 vrp_initialize (void) | |
5296 { | |
5297 basic_block bb; | |
5298 | |
5299 vr_value = XCNEWVEC (value_range_t *, num_ssa_names); | |
5300 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names); | |
5301 | |
5302 FOR_EACH_BB (bb) | |
5303 { | |
5304 gimple_stmt_iterator si; | |
5305 | |
5306 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si)) | |
5307 { | |
5308 gimple phi = gsi_stmt (si); | |
5309 if (!stmt_interesting_for_vrp (phi)) | |
5310 { | |
5311 tree lhs = PHI_RESULT (phi); | |
5312 set_value_range_to_varying (get_value_range (lhs)); | |
5313 prop_set_simulate_again (phi, false); | |
5314 } | |
5315 else | |
5316 prop_set_simulate_again (phi, true); | |
5317 } | |
5318 | |
5319 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) | |
5320 { | |
5321 gimple stmt = gsi_stmt (si); | |
5322 | |
5323 if (!stmt_interesting_for_vrp (stmt)) | |
5324 { | |
5325 ssa_op_iter i; | |
5326 tree def; | |
5327 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF) | |
5328 set_value_range_to_varying (get_value_range (def)); | |
5329 prop_set_simulate_again (stmt, false); | |
5330 } | |
5331 else | |
5332 { | |
5333 prop_set_simulate_again (stmt, true); | |
5334 } | |
5335 } | |
5336 } | |
5337 } | |
5338 | |
5339 | |
5340 /* Visit assignment STMT. If it produces an interesting range, record | |
5341 the SSA name in *OUTPUT_P. */ | |
5342 | |
5343 static enum ssa_prop_result | |
5344 vrp_visit_assignment_or_call (gimple stmt, tree *output_p) | |
5345 { | |
5346 tree def, lhs; | |
5347 ssa_op_iter iter; | |
5348 enum gimple_code code = gimple_code (stmt); | |
5349 lhs = gimple_get_lhs (stmt); | |
5350 | |
5351 /* We only keep track of ranges in integral and pointer types. */ | |
5352 if (TREE_CODE (lhs) == SSA_NAME | |
5353 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs)) | |
5354 /* It is valid to have NULL MIN/MAX values on a type. See | |
5355 build_range_type. */ | |
5356 && TYPE_MIN_VALUE (TREE_TYPE (lhs)) | |
5357 && TYPE_MAX_VALUE (TREE_TYPE (lhs))) | |
5358 || POINTER_TYPE_P (TREE_TYPE (lhs)))) | |
5359 { | |
5360 struct loop *l; | |
5361 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL }; | |
5362 | |
5363 if (code == GIMPLE_CALL) | |
5364 extract_range_basic (&new_vr, stmt); | |
5365 else | |
5366 extract_range_from_assignment (&new_vr, stmt); | |
5367 | |
5368 /* If STMT is inside a loop, we may be able to know something | |
5369 else about the range of LHS by examining scalar evolution | |
5370 information. */ | |
5371 if (current_loops && (l = loop_containing_stmt (stmt))) | |
5372 adjust_range_with_scev (&new_vr, l, stmt, lhs); | |
5373 | |
5374 if (update_value_range (lhs, &new_vr)) | |
5375 { | |
5376 *output_p = lhs; | |
5377 | |
5378 if (dump_file && (dump_flags & TDF_DETAILS)) | |
5379 { | |
5380 fprintf (dump_file, "Found new range for "); | |
5381 print_generic_expr (dump_file, lhs, 0); | |
5382 fprintf (dump_file, ": "); | |
5383 dump_value_range (dump_file, &new_vr); | |
5384 fprintf (dump_file, "\n\n"); | |
5385 } | |
5386 | |
5387 if (new_vr.type == VR_VARYING) | |
5388 return SSA_PROP_VARYING; | |
5389 | |
5390 return SSA_PROP_INTERESTING; | |
5391 } | |
5392 | |
5393 return SSA_PROP_NOT_INTERESTING; | |
5394 } | |
5395 | |
5396 /* Every other statement produces no useful ranges. */ | |
5397 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF) | |
5398 set_value_range_to_varying (get_value_range (def)); | |
5399 | |
5400 return SSA_PROP_VARYING; | |
5401 } | |
5402 | |
5403 /* Helper that gets the value range of the SSA_NAME with version I | |
5404 or a symbolic range containing the SSA_NAME only if the value range | |
5405 is varying or undefined. */ | |
5406 | |
5407 static inline value_range_t | |
5408 get_vr_for_comparison (int i) | |
5409 { | |
5410 value_range_t vr = *(vr_value[i]); | |
5411 | |
5412 /* If name N_i does not have a valid range, use N_i as its own | |
5413 range. This allows us to compare against names that may | |
5414 have N_i in their ranges. */ | |
5415 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED) | |
5416 { | |
5417 vr.type = VR_RANGE; | |
5418 vr.min = ssa_name (i); | |
5419 vr.max = ssa_name (i); | |
5420 } | |
5421 | |
5422 return vr; | |
5423 } | |
5424 | |
5425 /* Compare all the value ranges for names equivalent to VAR with VAL | |
5426 using comparison code COMP. Return the same value returned by | |
5427 compare_range_with_value, including the setting of | |
5428 *STRICT_OVERFLOW_P. */ | |
5429 | |
5430 static tree | |
5431 compare_name_with_value (enum tree_code comp, tree var, tree val, | |
5432 bool *strict_overflow_p) | |
5433 { | |
5434 bitmap_iterator bi; | |
5435 unsigned i; | |
5436 bitmap e; | |
5437 tree retval, t; | |
5438 int used_strict_overflow; | |
5439 bool sop; | |
5440 value_range_t equiv_vr; | |
5441 | |
5442 /* Get the set of equivalences for VAR. */ | |
5443 e = get_value_range (var)->equiv; | |
5444 | |
5445 /* Start at -1. Set it to 0 if we do a comparison without relying | |
5446 on overflow, or 1 if all comparisons rely on overflow. */ | |
5447 used_strict_overflow = -1; | |
5448 | |
5449 /* Compare vars' value range with val. */ | |
5450 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var)); | |
5451 sop = false; | |
5452 retval = compare_range_with_value (comp, &equiv_vr, val, &sop); | |
5453 if (retval) | |
5454 used_strict_overflow = sop ? 1 : 0; | |
5455 | |
5456 /* If the equiv set is empty we have done all work we need to do. */ | |
5457 if (e == NULL) | |
5458 { | |
5459 if (retval | |
5460 && used_strict_overflow > 0) | |
5461 *strict_overflow_p = true; | |
5462 return retval; | |
5463 } | |
5464 | |
5465 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi) | |
5466 { | |
5467 equiv_vr = get_vr_for_comparison (i); | |
5468 sop = false; | |
5469 t = compare_range_with_value (comp, &equiv_vr, val, &sop); | |
5470 if (t) | |
5471 { | |
5472 /* If we get different answers from different members | |
5473 of the equivalence set this check must be in a dead | |
5474 code region. Folding it to a trap representation | |
5475 would be correct here. For now just return don't-know. */ | |
5476 if (retval != NULL | |
5477 && t != retval) | |
5478 { | |
5479 retval = NULL_TREE; | |
5480 break; | |
5481 } | |
5482 retval = t; | |
5483 | |
5484 if (!sop) | |
5485 used_strict_overflow = 0; | |
5486 else if (used_strict_overflow < 0) | |
5487 used_strict_overflow = 1; | |
5488 } | |
5489 } | |
5490 | |
5491 if (retval | |
5492 && used_strict_overflow > 0) | |
5493 *strict_overflow_p = true; | |
5494 | |
5495 return retval; | |
5496 } | |
5497 | |
5498 | |
5499 /* Given a comparison code COMP and names N1 and N2, compare all the | |
5500 ranges equivalent to N1 against all the ranges equivalent to N2 | |
5501 to determine the value of N1 COMP N2. Return the same value | |
5502 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate | |
5503 whether we relied on an overflow infinity in the comparison. */ | |
5504 | |
5505 | |
5506 static tree | |
5507 compare_names (enum tree_code comp, tree n1, tree n2, | |
5508 bool *strict_overflow_p) | |
5509 { | |
5510 tree t, retval; | |
5511 bitmap e1, e2; | |
5512 bitmap_iterator bi1, bi2; | |
5513 unsigned i1, i2; | |
5514 int used_strict_overflow; | |
5515 static bitmap_obstack *s_obstack = NULL; | |
5516 static bitmap s_e1 = NULL, s_e2 = NULL; | |
5517 | |
5518 /* Compare the ranges of every name equivalent to N1 against the | |
5519 ranges of every name equivalent to N2. */ | |
5520 e1 = get_value_range (n1)->equiv; | |
5521 e2 = get_value_range (n2)->equiv; | |
5522 | |
5523 /* Use the fake bitmaps if e1 or e2 are not available. */ | |
5524 if (s_obstack == NULL) | |
5525 { | |
5526 s_obstack = XNEW (bitmap_obstack); | |
5527 bitmap_obstack_initialize (s_obstack); | |
5528 s_e1 = BITMAP_ALLOC (s_obstack); | |
5529 s_e2 = BITMAP_ALLOC (s_obstack); | |
5530 } | |
5531 if (e1 == NULL) | |
5532 e1 = s_e1; | |
5533 if (e2 == NULL) | |
5534 e2 = s_e2; | |
5535 | |
5536 /* Add N1 and N2 to their own set of equivalences to avoid | |
5537 duplicating the body of the loop just to check N1 and N2 | |
5538 ranges. */ | |
5539 bitmap_set_bit (e1, SSA_NAME_VERSION (n1)); | |
5540 bitmap_set_bit (e2, SSA_NAME_VERSION (n2)); | |
5541 | |
5542 /* If the equivalence sets have a common intersection, then the two | |
5543 names can be compared without checking their ranges. */ | |
5544 if (bitmap_intersect_p (e1, e2)) | |
5545 { | |
5546 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1)); | |
5547 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2)); | |
5548 | |
5549 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR) | |
5550 ? boolean_true_node | |
5551 : boolean_false_node; | |
5552 } | |
5553 | |
5554 /* Start at -1. Set it to 0 if we do a comparison without relying | |
5555 on overflow, or 1 if all comparisons rely on overflow. */ | |
5556 used_strict_overflow = -1; | |
5557 | |
5558 /* Otherwise, compare all the equivalent ranges. First, add N1 and | |
5559 N2 to their own set of equivalences to avoid duplicating the body | |
5560 of the loop just to check N1 and N2 ranges. */ | |
5561 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1) | |
5562 { | |
5563 value_range_t vr1 = get_vr_for_comparison (i1); | |
5564 | |
5565 t = retval = NULL_TREE; | |
5566 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2) | |
5567 { | |
5568 bool sop = false; | |
5569 | |
5570 value_range_t vr2 = get_vr_for_comparison (i2); | |
5571 | |
5572 t = compare_ranges (comp, &vr1, &vr2, &sop); | |
5573 if (t) | |
5574 { | |
5575 /* If we get different answers from different members | |
5576 of the equivalence set this check must be in a dead | |
5577 code region. Folding it to a trap representation | |
5578 would be correct here. For now just return don't-know. */ | |
5579 if (retval != NULL | |
5580 && t != retval) | |
5581 { | |
5582 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1)); | |
5583 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2)); | |
5584 return NULL_TREE; | |
5585 } | |
5586 retval = t; | |
5587 | |
5588 if (!sop) | |
5589 used_strict_overflow = 0; | |
5590 else if (used_strict_overflow < 0) | |
5591 used_strict_overflow = 1; | |
5592 } | |
5593 } | |
5594 | |
5595 if (retval) | |
5596 { | |
5597 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1)); | |
5598 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2)); | |
5599 if (used_strict_overflow > 0) | |
5600 *strict_overflow_p = true; | |
5601 return retval; | |
5602 } | |
5603 } | |
5604 | |
5605 /* None of the equivalent ranges are useful in computing this | |
5606 comparison. */ | |
5607 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1)); | |
5608 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2)); | |
5609 return NULL_TREE; | |
5610 } | |
5611 | |
5612 /* Helper function for vrp_evaluate_conditional_warnv. */ | |
5613 | |
5614 static tree | |
5615 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code, | |
5616 tree op0, tree op1, | |
5617 bool * strict_overflow_p) | |
5618 { | |
5619 value_range_t *vr0, *vr1; | |
5620 | |
5621 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL; | |
5622 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL; | |
5623 | |
5624 if (vr0 && vr1) | |
5625 return compare_ranges (code, vr0, vr1, strict_overflow_p); | |
5626 else if (vr0 && vr1 == NULL) | |
5627 return compare_range_with_value (code, vr0, op1, strict_overflow_p); | |
5628 else if (vr0 == NULL && vr1) | |
5629 return (compare_range_with_value | |
5630 (swap_tree_comparison (code), vr1, op0, strict_overflow_p)); | |
5631 return NULL; | |
5632 } | |
5633 | |
5634 /* Helper function for vrp_evaluate_conditional_warnv. */ | |
5635 | |
5636 static tree | |
5637 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0, | |
5638 tree op1, bool use_equiv_p, | |
5639 bool *strict_overflow_p, bool *only_ranges) | |
5640 { | |
5641 tree ret; | |
5642 if (only_ranges) | |
5643 *only_ranges = true; | |
5644 | |
5645 /* We only deal with integral and pointer types. */ | |
5646 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0)) | |
5647 && !POINTER_TYPE_P (TREE_TYPE (op0))) | |
5648 return NULL_TREE; | |
5649 | |
5650 if (use_equiv_p) | |
5651 { | |
5652 if (only_ranges | |
5653 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges | |
5654 (code, op0, op1, strict_overflow_p))) | |
5655 return ret; | |
5656 *only_ranges = false; | |
5657 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME) | |
5658 return compare_names (code, op0, op1, strict_overflow_p); | |
5659 else if (TREE_CODE (op0) == SSA_NAME) | |
5660 return compare_name_with_value (code, op0, op1, strict_overflow_p); | |
5661 else if (TREE_CODE (op1) == SSA_NAME) | |
5662 return (compare_name_with_value | |
5663 (swap_tree_comparison (code), op1, op0, strict_overflow_p)); | |
5664 } | |
5665 else | |
5666 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1, | |
5667 strict_overflow_p); | |
5668 return NULL_TREE; | |
5669 } | |
5670 | |
5671 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range | |
5672 information. Return NULL if the conditional can not be evaluated. | |
5673 The ranges of all the names equivalent with the operands in COND | |
5674 will be used when trying to compute the value. If the result is | |
5675 based on undefined signed overflow, issue a warning if | |
5676 appropriate. */ | |
5677 | |
5678 tree | |
5679 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt) | |
5680 { | |
5681 bool sop; | |
5682 tree ret; | |
5683 bool only_ranges; | |
5684 | |
5685 sop = false; | |
5686 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop, | |
5687 &only_ranges); | |
5688 | |
5689 if (ret && sop) | |
5690 { | |
5691 enum warn_strict_overflow_code wc; | |
5692 const char* warnmsg; | |
5693 | |
5694 if (is_gimple_min_invariant (ret)) | |
5695 { | |
5696 wc = WARN_STRICT_OVERFLOW_CONDITIONAL; | |
5697 warnmsg = G_("assuming signed overflow does not occur when " | |
5698 "simplifying conditional to constant"); | |
5699 } | |
5700 else | |
5701 { | |
5702 wc = WARN_STRICT_OVERFLOW_COMPARISON; | |
5703 warnmsg = G_("assuming signed overflow does not occur when " | |
5704 "simplifying conditional"); | |
5705 } | |
5706 | |
5707 if (issue_strict_overflow_warning (wc)) | |
5708 { | |
5709 location_t location; | |
5710 | |
5711 if (!gimple_has_location (stmt)) | |
5712 location = input_location; | |
5713 else | |
5714 location = gimple_location (stmt); | |
5715 warning (OPT_Wstrict_overflow, "%H%s", &location, warnmsg); | |
5716 } | |
5717 } | |
5718 | |
5719 if (warn_type_limits | |
5720 && ret && only_ranges | |
5721 && TREE_CODE_CLASS (code) == tcc_comparison | |
5722 && TREE_CODE (op0) == SSA_NAME) | |
5723 { | |
5724 /* If the comparison is being folded and the operand on the LHS | |
5725 is being compared against a constant value that is outside of | |
5726 the natural range of OP0's type, then the predicate will | |
5727 always fold regardless of the value of OP0. If -Wtype-limits | |
5728 was specified, emit a warning. */ | |
5729 const char *warnmsg = NULL; | |
5730 tree type = TREE_TYPE (op0); | |
5731 value_range_t *vr0 = get_value_range (op0); | |
5732 | |
5733 if (vr0->type != VR_VARYING | |
5734 && INTEGRAL_TYPE_P (type) | |
5735 && vrp_val_is_min (vr0->min) | |
5736 && vrp_val_is_max (vr0->max) | |
5737 && is_gimple_min_invariant (op1)) | |
5738 { | |
5739 if (integer_zerop (ret)) | |
5740 warnmsg = G_("comparison always false due to limited range of " | |
5741 "data type"); | |
5742 else | |
5743 warnmsg = G_("comparison always true due to limited range of " | |
5744 "data type"); | |
5745 } | |
5746 | |
5747 if (warnmsg) | |
5748 { | |
5749 location_t location; | |
5750 | |
5751 if (!gimple_has_location (stmt)) | |
5752 location = input_location; | |
5753 else | |
5754 location = gimple_location (stmt); | |
5755 | |
5756 warning (OPT_Wtype_limits, "%H%s", &location, warnmsg); | |
5757 } | |
5758 } | |
5759 | |
5760 return ret; | |
5761 } | |
5762 | |
5763 | |
5764 /* Visit conditional statement STMT. If we can determine which edge | |
5765 will be taken out of STMT's basic block, record it in | |
5766 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return | |
5767 SSA_PROP_VARYING. */ | |
5768 | |
5769 static enum ssa_prop_result | |
5770 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p) | |
5771 { | |
5772 tree val; | |
5773 bool sop; | |
5774 | |
5775 *taken_edge_p = NULL; | |
5776 | |
5777 if (dump_file && (dump_flags & TDF_DETAILS)) | |
5778 { | |
5779 tree use; | |
5780 ssa_op_iter i; | |
5781 | |
5782 fprintf (dump_file, "\nVisiting conditional with predicate: "); | |
5783 print_gimple_stmt (dump_file, stmt, 0, 0); | |
5784 fprintf (dump_file, "\nWith known ranges\n"); | |
5785 | |
5786 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE) | |
5787 { | |
5788 fprintf (dump_file, "\t"); | |
5789 print_generic_expr (dump_file, use, 0); | |
5790 fprintf (dump_file, ": "); | |
5791 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]); | |
5792 } | |
5793 | |
5794 fprintf (dump_file, "\n"); | |
5795 } | |
5796 | |
5797 /* Compute the value of the predicate COND by checking the known | |
5798 ranges of each of its operands. | |
5799 | |
5800 Note that we cannot evaluate all the equivalent ranges here | |
5801 because those ranges may not yet be final and with the current | |
5802 propagation strategy, we cannot determine when the value ranges | |
5803 of the names in the equivalence set have changed. | |
5804 | |
5805 For instance, given the following code fragment | |
5806 | |
5807 i_5 = PHI <8, i_13> | |
5808 ... | |
5809 i_14 = ASSERT_EXPR <i_5, i_5 != 0> | |
5810 if (i_14 == 1) | |
5811 ... | |
5812 | |
5813 Assume that on the first visit to i_14, i_5 has the temporary | |
5814 range [8, 8] because the second argument to the PHI function is | |
5815 not yet executable. We derive the range ~[0, 0] for i_14 and the | |
5816 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for | |
5817 the first time, since i_14 is equivalent to the range [8, 8], we | |
5818 determine that the predicate is always false. | |
5819 | |
5820 On the next round of propagation, i_13 is determined to be | |
5821 VARYING, which causes i_5 to drop down to VARYING. So, another | |
5822 visit to i_14 is scheduled. In this second visit, we compute the | |
5823 exact same range and equivalence set for i_14, namely ~[0, 0] and | |
5824 { i_5 }. But we did not have the previous range for i_5 | |
5825 registered, so vrp_visit_assignment thinks that the range for | |
5826 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)' | |
5827 is not visited again, which stops propagation from visiting | |
5828 statements in the THEN clause of that if(). | |
5829 | |
5830 To properly fix this we would need to keep the previous range | |
5831 value for the names in the equivalence set. This way we would've | |
5832 discovered that from one visit to the other i_5 changed from | |
5833 range [8, 8] to VR_VARYING. | |
5834 | |
5835 However, fixing this apparent limitation may not be worth the | |
5836 additional checking. Testing on several code bases (GCC, DLV, | |
5837 MICO, TRAMP3D and SPEC2000) showed that doing this results in | |
5838 4 more predicates folded in SPEC. */ | |
5839 sop = false; | |
5840 | |
5841 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt), | |
5842 gimple_cond_lhs (stmt), | |
5843 gimple_cond_rhs (stmt), | |
5844 false, &sop, NULL); | |
5845 if (val) | |
5846 { | |
5847 if (!sop) | |
5848 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val); | |
5849 else | |
5850 { | |
5851 if (dump_file && (dump_flags & TDF_DETAILS)) | |
5852 fprintf (dump_file, | |
5853 "\nIgnoring predicate evaluation because " | |
5854 "it assumes that signed overflow is undefined"); | |
5855 val = NULL_TREE; | |
5856 } | |
5857 } | |
5858 | |
5859 if (dump_file && (dump_flags & TDF_DETAILS)) | |
5860 { | |
5861 fprintf (dump_file, "\nPredicate evaluates to: "); | |
5862 if (val == NULL_TREE) | |
5863 fprintf (dump_file, "DON'T KNOW\n"); | |
5864 else | |
5865 print_generic_stmt (dump_file, val, 0); | |
5866 } | |
5867 | |
5868 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING; | |
5869 } | |
5870 | |
5871 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL | |
5872 that includes the value VAL. The search is restricted to the range | |
5873 [START_IDX, n - 1] where n is the size of VEC. | |
5874 | |
5875 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is | |
5876 returned. | |
5877 | |
5878 If there is no CASE_LABEL for VAL and the is one that is larger than VAL, | |
5879 it is placed in IDX and false is returned. | |
5880 | |
5881 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is | |
5882 returned. */ | |
5883 | |
5884 static bool | |
5885 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx) | |
5886 { | |
5887 size_t n = gimple_switch_num_labels (stmt); | |
5888 size_t low, high; | |
5889 | |
5890 /* Find case label for minimum of the value range or the next one. | |
5891 At each iteration we are searching in [low, high - 1]. */ | |
5892 | |
5893 for (low = start_idx, high = n; high != low; ) | |
5894 { | |
5895 tree t; | |
5896 int cmp; | |
5897 /* Note that i != high, so we never ask for n. */ | |
5898 size_t i = (high + low) / 2; | |
5899 t = gimple_switch_label (stmt, i); | |
5900 | |
5901 /* Cache the result of comparing CASE_LOW and val. */ | |
5902 cmp = tree_int_cst_compare (CASE_LOW (t), val); | |
5903 | |
5904 if (cmp == 0) | |
5905 { | |
5906 /* Ranges cannot be empty. */ | |
5907 *idx = i; | |
5908 return true; | |
5909 } | |
5910 else if (cmp > 0) | |
5911 high = i; | |
5912 else | |
5913 { | |
5914 low = i + 1; | |
5915 if (CASE_HIGH (t) != NULL | |
5916 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0) | |
5917 { | |
5918 *idx = i; | |
5919 return true; | |
5920 } | |
5921 } | |
5922 } | |
5923 | |
5924 *idx = high; | |
5925 return false; | |
5926 } | |
5927 | |
5928 /* Searches the case label vector VEC for the range of CASE_LABELs that is used | |
5929 for values between MIN and MAX. The first index is placed in MIN_IDX. The | |
5930 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty | |
5931 then MAX_IDX < MIN_IDX. | |
5932 Returns true if the default label is not needed. */ | |
5933 | |
5934 static bool | |
5935 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx, | |
5936 size_t *max_idx) | |
5937 { | |
5938 size_t i, j; | |
5939 bool min_take_default = !find_case_label_index (stmt, 1, min, &i); | |
5940 bool max_take_default = !find_case_label_index (stmt, i, max, &j); | |
5941 | |
5942 if (i == j | |
5943 && min_take_default | |
5944 && max_take_default) | |
5945 { | |
5946 /* Only the default case label reached. | |
5947 Return an empty range. */ | |
5948 *min_idx = 1; | |
5949 *max_idx = 0; | |
5950 return false; | |
5951 } | |
5952 else | |
5953 { | |
5954 bool take_default = min_take_default || max_take_default; | |
5955 tree low, high; | |
5956 size_t k; | |
5957 | |
5958 if (max_take_default) | |
5959 j--; | |
5960 | |
5961 /* If the case label range is continuous, we do not need | |
5962 the default case label. Verify that. */ | |
5963 high = CASE_LOW (gimple_switch_label (stmt, i)); | |
5964 if (CASE_HIGH (gimple_switch_label (stmt, i))) | |
5965 high = CASE_HIGH (gimple_switch_label (stmt, i)); | |
5966 for (k = i + 1; k <= j; ++k) | |
5967 { | |
5968 low = CASE_LOW (gimple_switch_label (stmt, k)); | |
5969 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high, 0))) | |
5970 { | |
5971 take_default = true; | |
5972 break; | |
5973 } | |
5974 high = low; | |
5975 if (CASE_HIGH (gimple_switch_label (stmt, k))) | |
5976 high = CASE_HIGH (gimple_switch_label (stmt, k)); | |
5977 } | |
5978 | |
5979 *min_idx = i; | |
5980 *max_idx = j; | |
5981 return !take_default; | |
5982 } | |
5983 } | |
5984 | |
5985 /* Visit switch statement STMT. If we can determine which edge | |
5986 will be taken out of STMT's basic block, record it in | |
5987 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return | |
5988 SSA_PROP_VARYING. */ | |
5989 | |
5990 static enum ssa_prop_result | |
5991 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p) | |
5992 { | |
5993 tree op, val; | |
5994 value_range_t *vr; | |
5995 size_t i = 0, j = 0, n; | |
5996 bool take_default; | |
5997 | |
5998 *taken_edge_p = NULL; | |
5999 op = gimple_switch_index (stmt); | |
6000 if (TREE_CODE (op) != SSA_NAME) | |
6001 return SSA_PROP_VARYING; | |
6002 | |
6003 vr = get_value_range (op); | |
6004 if (dump_file && (dump_flags & TDF_DETAILS)) | |
6005 { | |
6006 fprintf (dump_file, "\nVisiting switch expression with operand "); | |
6007 print_generic_expr (dump_file, op, 0); | |
6008 fprintf (dump_file, " with known range "); | |
6009 dump_value_range (dump_file, vr); | |
6010 fprintf (dump_file, "\n"); | |
6011 } | |
6012 | |
6013 if (vr->type != VR_RANGE | |
6014 || symbolic_range_p (vr)) | |
6015 return SSA_PROP_VARYING; | |
6016 | |
6017 /* Find the single edge that is taken from the switch expression. */ | |
6018 n = gimple_switch_num_labels (stmt); | |
6019 | |
6020 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j); | |
6021 | |
6022 /* Check if the range spans no CASE_LABEL. If so, we only reach the default | |
6023 label */ | |
6024 if (j < i) | |
6025 { | |
6026 gcc_assert (take_default); | |
6027 val = gimple_switch_default_label (stmt); | |
6028 } | |
6029 else | |
6030 { | |
6031 /* Check if labels with index i to j and maybe the default label | |
6032 are all reaching the same label. */ | |
6033 | |
6034 val = gimple_switch_label (stmt, i); | |
6035 if (take_default | |
6036 && CASE_LABEL (gimple_switch_default_label (stmt)) | |
6037 != CASE_LABEL (val)) | |
6038 { | |
6039 if (dump_file && (dump_flags & TDF_DETAILS)) | |
6040 fprintf (dump_file, " not a single destination for this " | |
6041 "range\n"); | |
6042 return SSA_PROP_VARYING; | |
6043 } | |
6044 for (++i; i <= j; ++i) | |
6045 { | |
6046 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val)) | |
6047 { | |
6048 if (dump_file && (dump_flags & TDF_DETAILS)) | |
6049 fprintf (dump_file, " not a single destination for this " | |
6050 "range\n"); | |
6051 return SSA_PROP_VARYING; | |
6052 } | |
6053 } | |
6054 } | |
6055 | |
6056 *taken_edge_p = find_edge (gimple_bb (stmt), | |
6057 label_to_block (CASE_LABEL (val))); | |
6058 | |
6059 if (dump_file && (dump_flags & TDF_DETAILS)) | |
6060 { | |
6061 fprintf (dump_file, " will take edge to "); | |
6062 print_generic_stmt (dump_file, CASE_LABEL (val), 0); | |
6063 } | |
6064 | |
6065 return SSA_PROP_INTERESTING; | |
6066 } | |
6067 | |
6068 | |
6069 /* Evaluate statement STMT. If the statement produces a useful range, | |
6070 return SSA_PROP_INTERESTING and record the SSA name with the | |
6071 interesting range into *OUTPUT_P. | |
6072 | |
6073 If STMT is a conditional branch and we can determine its truth | |
6074 value, the taken edge is recorded in *TAKEN_EDGE_P. | |
6075 | |
6076 If STMT produces a varying value, return SSA_PROP_VARYING. */ | |
6077 | |
6078 static enum ssa_prop_result | |
6079 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p) | |
6080 { | |
6081 tree def; | |
6082 ssa_op_iter iter; | |
6083 | |
6084 if (dump_file && (dump_flags & TDF_DETAILS)) | |
6085 { | |
6086 fprintf (dump_file, "\nVisiting statement:\n"); | |
6087 print_gimple_stmt (dump_file, stmt, 0, dump_flags); | |
6088 fprintf (dump_file, "\n"); | |
6089 } | |
6090 | |
6091 if (is_gimple_assign (stmt) || is_gimple_call (stmt)) | |
6092 { | |
6093 /* In general, assignments with virtual operands are not useful | |
6094 for deriving ranges, with the obvious exception of calls to | |
6095 builtin functions. */ | |
6096 | |
6097 if ((is_gimple_call (stmt) | |
6098 && gimple_call_fndecl (stmt) != NULL_TREE | |
6099 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt))) | |
6100 || ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)) | |
6101 return vrp_visit_assignment_or_call (stmt, output_p); | |
6102 } | |
6103 else if (gimple_code (stmt) == GIMPLE_COND) | |
6104 return vrp_visit_cond_stmt (stmt, taken_edge_p); | |
6105 else if (gimple_code (stmt) == GIMPLE_SWITCH) | |
6106 return vrp_visit_switch_stmt (stmt, taken_edge_p); | |
6107 | |
6108 /* All other statements produce nothing of interest for VRP, so mark | |
6109 their outputs varying and prevent further simulation. */ | |
6110 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF) | |
6111 set_value_range_to_varying (get_value_range (def)); | |
6112 | |
6113 return SSA_PROP_VARYING; | |
6114 } | |
6115 | |
6116 | |
6117 /* Meet operation for value ranges. Given two value ranges VR0 and | |
6118 VR1, store in VR0 a range that contains both VR0 and VR1. This | |
6119 may not be the smallest possible such range. */ | |
6120 | |
6121 static void | |
6122 vrp_meet (value_range_t *vr0, value_range_t *vr1) | |
6123 { | |
6124 if (vr0->type == VR_UNDEFINED) | |
6125 { | |
6126 copy_value_range (vr0, vr1); | |
6127 return; | |
6128 } | |
6129 | |
6130 if (vr1->type == VR_UNDEFINED) | |
6131 { | |
6132 /* Nothing to do. VR0 already has the resulting range. */ | |
6133 return; | |
6134 } | |
6135 | |
6136 if (vr0->type == VR_VARYING) | |
6137 { | |
6138 /* Nothing to do. VR0 already has the resulting range. */ | |
6139 return; | |
6140 } | |
6141 | |
6142 if (vr1->type == VR_VARYING) | |
6143 { | |
6144 set_value_range_to_varying (vr0); | |
6145 return; | |
6146 } | |
6147 | |
6148 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE) | |
6149 { | |
6150 int cmp; | |
6151 tree min, max; | |
6152 | |
6153 /* Compute the convex hull of the ranges. The lower limit of | |
6154 the new range is the minimum of the two ranges. If they | |
6155 cannot be compared, then give up. */ | |
6156 cmp = compare_values (vr0->min, vr1->min); | |
6157 if (cmp == 0 || cmp == 1) | |
6158 min = vr1->min; | |
6159 else if (cmp == -1) | |
6160 min = vr0->min; | |
6161 else | |
6162 goto give_up; | |
6163 | |
6164 /* Similarly, the upper limit of the new range is the maximum | |
6165 of the two ranges. If they cannot be compared, then | |
6166 give up. */ | |
6167 cmp = compare_values (vr0->max, vr1->max); | |
6168 if (cmp == 0 || cmp == -1) | |
6169 max = vr1->max; | |
6170 else if (cmp == 1) | |
6171 max = vr0->max; | |
6172 else | |
6173 goto give_up; | |
6174 | |
6175 /* Check for useless ranges. */ | |
6176 if (INTEGRAL_TYPE_P (TREE_TYPE (min)) | |
6177 && ((vrp_val_is_min (min) || is_overflow_infinity (min)) | |
6178 && (vrp_val_is_max (max) || is_overflow_infinity (max)))) | |
6179 goto give_up; | |
6180 | |
6181 /* The resulting set of equivalences is the intersection of | |
6182 the two sets. */ | |
6183 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv) | |
6184 bitmap_and_into (vr0->equiv, vr1->equiv); | |
6185 else if (vr0->equiv && !vr1->equiv) | |
6186 bitmap_clear (vr0->equiv); | |
6187 | |
6188 set_value_range (vr0, vr0->type, min, max, vr0->equiv); | |
6189 } | |
6190 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE) | |
6191 { | |
6192 /* Two anti-ranges meet only if their complements intersect. | |
6193 Only handle the case of identical ranges. */ | |
6194 if (compare_values (vr0->min, vr1->min) == 0 | |
6195 && compare_values (vr0->max, vr1->max) == 0 | |
6196 && compare_values (vr0->min, vr0->max) == 0) | |
6197 { | |
6198 /* The resulting set of equivalences is the intersection of | |
6199 the two sets. */ | |
6200 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv) | |
6201 bitmap_and_into (vr0->equiv, vr1->equiv); | |
6202 else if (vr0->equiv && !vr1->equiv) | |
6203 bitmap_clear (vr0->equiv); | |
6204 } | |
6205 else | |
6206 goto give_up; | |
6207 } | |
6208 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE) | |
6209 { | |
6210 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4], | |
6211 only handle the case where the ranges have an empty intersection. | |
6212 The result of the meet operation is the anti-range. */ | |
6213 if (!symbolic_range_p (vr0) | |
6214 && !symbolic_range_p (vr1) | |
6215 && !value_ranges_intersect_p (vr0, vr1)) | |
6216 { | |
6217 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence | |
6218 set. We need to compute the intersection of the two | |
6219 equivalence sets. */ | |
6220 if (vr1->type == VR_ANTI_RANGE) | |
6221 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv); | |
6222 | |
6223 /* The resulting set of equivalences is the intersection of | |
6224 the two sets. */ | |
6225 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv) | |
6226 bitmap_and_into (vr0->equiv, vr1->equiv); | |
6227 else if (vr0->equiv && !vr1->equiv) | |
6228 bitmap_clear (vr0->equiv); | |
6229 } | |
6230 else | |
6231 goto give_up; | |
6232 } | |
6233 else | |
6234 gcc_unreachable (); | |
6235 | |
6236 return; | |
6237 | |
6238 give_up: | |
6239 /* Failed to find an efficient meet. Before giving up and setting | |
6240 the result to VARYING, see if we can at least derive a useful | |
6241 anti-range. FIXME, all this nonsense about distinguishing | |
6242 anti-ranges from ranges is necessary because of the odd | |
6243 semantics of range_includes_zero_p and friends. */ | |
6244 if (!symbolic_range_p (vr0) | |
6245 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0)) | |
6246 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0))) | |
6247 && !symbolic_range_p (vr1) | |
6248 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1)) | |
6249 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1)))) | |
6250 { | |
6251 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min)); | |
6252 | |
6253 /* Since this meet operation did not result from the meeting of | |
6254 two equivalent names, VR0 cannot have any equivalences. */ | |
6255 if (vr0->equiv) | |
6256 bitmap_clear (vr0->equiv); | |
6257 } | |
6258 else | |
6259 set_value_range_to_varying (vr0); | |
6260 } | |
6261 | |
6262 | |
6263 /* Visit all arguments for PHI node PHI that flow through executable | |
6264 edges. If a valid value range can be derived from all the incoming | |
6265 value ranges, set a new range for the LHS of PHI. */ | |
6266 | |
6267 static enum ssa_prop_result | |
6268 vrp_visit_phi_node (gimple phi) | |
6269 { | |
6270 size_t i; | |
6271 tree lhs = PHI_RESULT (phi); | |
6272 value_range_t *lhs_vr = get_value_range (lhs); | |
6273 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL }; | |
6274 int edges, old_edges; | |
6275 | |
6276 copy_value_range (&vr_result, lhs_vr); | |
6277 | |
6278 if (dump_file && (dump_flags & TDF_DETAILS)) | |
6279 { | |
6280 fprintf (dump_file, "\nVisiting PHI node: "); | |
6281 print_gimple_stmt (dump_file, phi, 0, dump_flags); | |
6282 } | |
6283 | |
6284 edges = 0; | |
6285 for (i = 0; i < gimple_phi_num_args (phi); i++) | |
6286 { | |
6287 edge e = gimple_phi_arg_edge (phi, i); | |
6288 | |
6289 if (dump_file && (dump_flags & TDF_DETAILS)) | |
6290 { | |
6291 fprintf (dump_file, | |
6292 "\n Argument #%d (%d -> %d %sexecutable)\n", | |
6293 (int) i, e->src->index, e->dest->index, | |
6294 (e->flags & EDGE_EXECUTABLE) ? "" : "not "); | |
6295 } | |
6296 | |
6297 if (e->flags & EDGE_EXECUTABLE) | |
6298 { | |
6299 tree arg = PHI_ARG_DEF (phi, i); | |
6300 value_range_t vr_arg; | |
6301 | |
6302 ++edges; | |
6303 | |
6304 if (TREE_CODE (arg) == SSA_NAME) | |
6305 { | |
6306 vr_arg = *(get_value_range (arg)); | |
6307 } | |
6308 else | |
6309 { | |
6310 if (is_overflow_infinity (arg)) | |
6311 { | |
6312 arg = copy_node (arg); | |
6313 TREE_OVERFLOW (arg) = 0; | |
6314 } | |
6315 | |
6316 vr_arg.type = VR_RANGE; | |
6317 vr_arg.min = arg; | |
6318 vr_arg.max = arg; | |
6319 vr_arg.equiv = NULL; | |
6320 } | |
6321 | |
6322 if (dump_file && (dump_flags & TDF_DETAILS)) | |
6323 { | |
6324 fprintf (dump_file, "\t"); | |
6325 print_generic_expr (dump_file, arg, dump_flags); | |
6326 fprintf (dump_file, "\n\tValue: "); | |
6327 dump_value_range (dump_file, &vr_arg); | |
6328 fprintf (dump_file, "\n"); | |
6329 } | |
6330 | |
6331 vrp_meet (&vr_result, &vr_arg); | |
6332 | |
6333 if (vr_result.type == VR_VARYING) | |
6334 break; | |
6335 } | |
6336 } | |
6337 | |
6338 if (vr_result.type == VR_VARYING) | |
6339 goto varying; | |
6340 | |
6341 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)]; | |
6342 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges; | |
6343 | |
6344 /* To prevent infinite iterations in the algorithm, derive ranges | |
6345 when the new value is slightly bigger or smaller than the | |
6346 previous one. We don't do this if we have seen a new executable | |
6347 edge; this helps us avoid an overflow infinity for conditionals | |
6348 which are not in a loop. */ | |
6349 if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE | |
6350 && edges <= old_edges) | |
6351 { | |
6352 if (!POINTER_TYPE_P (TREE_TYPE (lhs))) | |
6353 { | |
6354 int cmp_min = compare_values (lhs_vr->min, vr_result.min); | |
6355 int cmp_max = compare_values (lhs_vr->max, vr_result.max); | |
6356 | |
6357 /* If the new minimum is smaller or larger than the previous | |
6358 one, go all the way to -INF. In the first case, to avoid | |
6359 iterating millions of times to reach -INF, and in the | |
6360 other case to avoid infinite bouncing between different | |
6361 minimums. */ | |
6362 if (cmp_min > 0 || cmp_min < 0) | |
6363 { | |
6364 /* If we will end up with a (-INF, +INF) range, set it to | |
6365 VARYING. Same if the previous max value was invalid for | |
6366 the type and we'd end up with vr_result.min > vr_result.max. */ | |
6367 if (vrp_val_is_max (vr_result.max) | |
6368 || compare_values (TYPE_MIN_VALUE (TREE_TYPE (vr_result.min)), | |
6369 vr_result.max) > 0) | |
6370 goto varying; | |
6371 | |
6372 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min)) | |
6373 || !vrp_var_may_overflow (lhs, phi)) | |
6374 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min)); | |
6375 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min))) | |
6376 vr_result.min = | |
6377 negative_overflow_infinity (TREE_TYPE (vr_result.min)); | |
6378 else | |
6379 goto varying; | |
6380 } | |
6381 | |
6382 /* Similarly, if the new maximum is smaller or larger than | |
6383 the previous one, go all the way to +INF. */ | |
6384 if (cmp_max < 0 || cmp_max > 0) | |
6385 { | |
6386 /* If we will end up with a (-INF, +INF) range, set it to | |
6387 VARYING. Same if the previous min value was invalid for | |
6388 the type and we'd end up with vr_result.max < vr_result.min. */ | |
6389 if (vrp_val_is_min (vr_result.min) | |
6390 || compare_values (TYPE_MAX_VALUE (TREE_TYPE (vr_result.max)), | |
6391 vr_result.min) < 0) | |
6392 goto varying; | |
6393 | |
6394 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max)) | |
6395 || !vrp_var_may_overflow (lhs, phi)) | |
6396 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max)); | |
6397 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max))) | |
6398 vr_result.max = | |
6399 positive_overflow_infinity (TREE_TYPE (vr_result.max)); | |
6400 else | |
6401 goto varying; | |
6402 } | |
6403 } | |
6404 } | |
6405 | |
6406 /* If the new range is different than the previous value, keep | |
6407 iterating. */ | |
6408 if (update_value_range (lhs, &vr_result)) | |
6409 return SSA_PROP_INTERESTING; | |
6410 | |
6411 /* Nothing changed, don't add outgoing edges. */ | |
6412 return SSA_PROP_NOT_INTERESTING; | |
6413 | |
6414 /* No match found. Set the LHS to VARYING. */ | |
6415 varying: | |
6416 set_value_range_to_varying (lhs_vr); | |
6417 return SSA_PROP_VARYING; | |
6418 } | |
6419 | |
6420 /* Simplify boolean operations if the source is known | |
6421 to be already a boolean. */ | |
6422 static bool | |
6423 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt) | |
6424 { | |
6425 enum tree_code rhs_code = gimple_assign_rhs_code (stmt); | |
6426 tree val = NULL; | |
6427 tree op0, op1; | |
6428 value_range_t *vr; | |
6429 bool sop = false; | |
6430 bool need_conversion; | |
6431 | |
6432 op0 = gimple_assign_rhs1 (stmt); | |
6433 if (TYPE_PRECISION (TREE_TYPE (op0)) != 1) | |
6434 { | |
6435 if (TREE_CODE (op0) != SSA_NAME) | |
6436 return false; | |
6437 vr = get_value_range (op0); | |
6438 | |
6439 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop); | |
6440 if (!val || !integer_onep (val)) | |
6441 return false; | |
6442 | |
6443 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop); | |
6444 if (!val || !integer_onep (val)) | |
6445 return false; | |
6446 } | |
6447 | |
6448 if (rhs_code == TRUTH_NOT_EXPR) | |
6449 { | |
6450 rhs_code = NE_EXPR; | |
6451 op1 = build_int_cst (TREE_TYPE (op0), 1); | |
6452 } | |
6453 else | |
6454 { | |
6455 op1 = gimple_assign_rhs2 (stmt); | |
6456 | |
6457 /* Reduce number of cases to handle. */ | |
6458 if (is_gimple_min_invariant (op1)) | |
6459 { | |
6460 /* Exclude anything that should have been already folded. */ | |
6461 if (rhs_code != EQ_EXPR | |
6462 && rhs_code != NE_EXPR | |
6463 && rhs_code != TRUTH_XOR_EXPR) | |
6464 return false; | |
6465 | |
6466 if (!integer_zerop (op1) | |
6467 && !integer_onep (op1) | |
6468 && !integer_all_onesp (op1)) | |
6469 return false; | |
6470 | |
6471 /* Limit the number of cases we have to consider. */ | |
6472 if (rhs_code == EQ_EXPR) | |
6473 { | |
6474 rhs_code = NE_EXPR; | |
6475 op1 = fold_unary (TRUTH_NOT_EXPR, TREE_TYPE (op1), op1); | |
6476 } | |
6477 } | |
6478 else | |
6479 { | |
6480 /* Punt on A == B as there is no BIT_XNOR_EXPR. */ | |
6481 if (rhs_code == EQ_EXPR) | |
6482 return false; | |
6483 | |
6484 if (TYPE_PRECISION (TREE_TYPE (op1)) != 1) | |
6485 { | |
6486 vr = get_value_range (op1); | |
6487 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop); | |
6488 if (!val || !integer_onep (val)) | |
6489 return false; | |
6490 | |
6491 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop); | |
6492 if (!val || !integer_onep (val)) | |
6493 return false; | |
6494 } | |
6495 } | |
6496 } | |
6497 | |
6498 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC)) | |
6499 { | |
6500 location_t location; | |
6501 | |
6502 if (!gimple_has_location (stmt)) | |
6503 location = input_location; | |
6504 else | |
6505 location = gimple_location (stmt); | |
6506 | |
6507 if (rhs_code == TRUTH_AND_EXPR || rhs_code == TRUTH_OR_EXPR) | |
6508 warning_at (location, OPT_Wstrict_overflow, | |
6509 _("assuming signed overflow does not occur when " | |
6510 "simplifying && or || to & or |")); | |
6511 else | |
6512 warning_at (location, OPT_Wstrict_overflow, | |
6513 _("assuming signed overflow does not occur when " | |
6514 "simplifying ==, != or ! to identity or ^")); | |
6515 } | |
6516 | |
6517 need_conversion = | |
6518 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)), | |
6519 TREE_TYPE (op0)); | |
6520 | |
6521 /* Make sure to not sign-extend -1 as a boolean value. */ | |
6522 if (need_conversion | |
6523 && !TYPE_UNSIGNED (TREE_TYPE (op0)) | |
6524 && TYPE_PRECISION (TREE_TYPE (op0)) == 1) | |
6525 return false; | |
6526 | |
6527 switch (rhs_code) | |
6528 { | |
6529 case TRUTH_AND_EXPR: | |
6530 rhs_code = BIT_AND_EXPR; | |
6531 break; | |
6532 case TRUTH_OR_EXPR: | |
6533 rhs_code = BIT_IOR_EXPR; | |
6534 break; | |
6535 case TRUTH_XOR_EXPR: | |
6536 case NE_EXPR: | |
6537 if (integer_zerop (op1)) | |
6538 { | |
6539 gimple_assign_set_rhs_with_ops (gsi, | |
6540 need_conversion ? NOP_EXPR : SSA_NAME, | |
6541 op0, NULL); | |
6542 update_stmt (gsi_stmt (*gsi)); | |
6543 return true; | |
6544 } | |
6545 | |
6546 rhs_code = BIT_XOR_EXPR; | |
6547 break; | |
6548 default: | |
6549 gcc_unreachable (); | |
6550 } | |
6551 | |
6552 if (need_conversion) | |
6553 return false; | |
6554 | |
6555 gimple_assign_set_rhs_with_ops (gsi, rhs_code, op0, op1); | |
6556 update_stmt (gsi_stmt (*gsi)); | |
6557 return true; | |
6558 } | |
6559 | |
6560 /* Simplify a division or modulo operator to a right shift or | |
6561 bitwise and if the first operand is unsigned or is greater | |
6562 than zero and the second operand is an exact power of two. */ | |
6563 | |
6564 static bool | |
6565 simplify_div_or_mod_using_ranges (gimple stmt) | |
6566 { | |
6567 enum tree_code rhs_code = gimple_assign_rhs_code (stmt); | |
6568 tree val = NULL; | |
6569 tree op0 = gimple_assign_rhs1 (stmt); | |
6570 tree op1 = gimple_assign_rhs2 (stmt); | |
6571 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt)); | |
6572 | |
6573 if (TYPE_UNSIGNED (TREE_TYPE (op0))) | |
6574 { | |
6575 val = integer_one_node; | |
6576 } | |
6577 else | |
6578 { | |
6579 bool sop = false; | |
6580 | |
6581 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop); | |
6582 | |
6583 if (val | |
6584 && sop | |
6585 && integer_onep (val) | |
6586 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC)) | |
6587 { | |
6588 location_t location; | |
6589 | |
6590 if (!gimple_has_location (stmt)) | |
6591 location = input_location; | |
6592 else | |
6593 location = gimple_location (stmt); | |
6594 warning (OPT_Wstrict_overflow, | |
6595 ("%Hassuming signed overflow does not occur when " | |
6596 "simplifying / or %% to >> or &"), | |
6597 &location); | |
6598 } | |
6599 } | |
6600 | |
6601 if (val && integer_onep (val)) | |
6602 { | |
6603 tree t; | |
6604 | |
6605 if (rhs_code == TRUNC_DIV_EXPR) | |
6606 { | |
6607 t = build_int_cst (NULL_TREE, tree_log2 (op1)); | |
6608 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR); | |
6609 gimple_assign_set_rhs1 (stmt, op0); | |
6610 gimple_assign_set_rhs2 (stmt, t); | |
6611 } | |
6612 else | |
6613 { | |
6614 t = build_int_cst (TREE_TYPE (op1), 1); | |
6615 t = int_const_binop (MINUS_EXPR, op1, t, 0); | |
6616 t = fold_convert (TREE_TYPE (op0), t); | |
6617 | |
6618 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR); | |
6619 gimple_assign_set_rhs1 (stmt, op0); | |
6620 gimple_assign_set_rhs2 (stmt, t); | |
6621 } | |
6622 | |
6623 update_stmt (stmt); | |
6624 return true; | |
6625 } | |
6626 | |
6627 return false; | |
6628 } | |
6629 | |
6630 /* If the operand to an ABS_EXPR is >= 0, then eliminate the | |
6631 ABS_EXPR. If the operand is <= 0, then simplify the | |
6632 ABS_EXPR into a NEGATE_EXPR. */ | |
6633 | |
6634 static bool | |
6635 simplify_abs_using_ranges (gimple stmt) | |
6636 { | |
6637 tree val = NULL; | |
6638 tree op = gimple_assign_rhs1 (stmt); | |
6639 tree type = TREE_TYPE (op); | |
6640 value_range_t *vr = get_value_range (op); | |
6641 | |
6642 if (TYPE_UNSIGNED (type)) | |
6643 { | |
6644 val = integer_zero_node; | |
6645 } | |
6646 else if (vr) | |
6647 { | |
6648 bool sop = false; | |
6649 | |
6650 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop); | |
6651 if (!val) | |
6652 { | |
6653 sop = false; | |
6654 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, | |
6655 &sop); | |
6656 | |
6657 if (val) | |
6658 { | |
6659 if (integer_zerop (val)) | |
6660 val = integer_one_node; | |
6661 else if (integer_onep (val)) | |
6662 val = integer_zero_node; | |
6663 } | |
6664 } | |
6665 | |
6666 if (val | |
6667 && (integer_onep (val) || integer_zerop (val))) | |
6668 { | |
6669 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC)) | |
6670 { | |
6671 location_t location; | |
6672 | |
6673 if (!gimple_has_location (stmt)) | |
6674 location = input_location; | |
6675 else | |
6676 location = gimple_location (stmt); | |
6677 warning (OPT_Wstrict_overflow, | |
6678 ("%Hassuming signed overflow does not occur when " | |
6679 "simplifying abs (X) to X or -X"), | |
6680 &location); | |
6681 } | |
6682 | |
6683 gimple_assign_set_rhs1 (stmt, op); | |
6684 if (integer_onep (val)) | |
6685 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR); | |
6686 else | |
6687 gimple_assign_set_rhs_code (stmt, SSA_NAME); | |
6688 update_stmt (stmt); | |
6689 return true; | |
6690 } | |
6691 } | |
6692 | |
6693 return false; | |
6694 } | |
6695 | |
6696 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has | |
6697 a known value range VR. | |
6698 | |
6699 If there is one and only one value which will satisfy the | |
6700 conditional, then return that value. Else return NULL. */ | |
6701 | |
6702 static tree | |
6703 test_for_singularity (enum tree_code cond_code, tree op0, | |
6704 tree op1, value_range_t *vr) | |
6705 { | |
6706 tree min = NULL; | |
6707 tree max = NULL; | |
6708 | |
6709 /* Extract minimum/maximum values which satisfy the | |
6710 the conditional as it was written. */ | |
6711 if (cond_code == LE_EXPR || cond_code == LT_EXPR) | |
6712 { | |
6713 /* This should not be negative infinity; there is no overflow | |
6714 here. */ | |
6715 min = TYPE_MIN_VALUE (TREE_TYPE (op0)); | |
6716 | |
6717 max = op1; | |
6718 if (cond_code == LT_EXPR && !is_overflow_infinity (max)) | |
6719 { | |
6720 tree one = build_int_cst (TREE_TYPE (op0), 1); | |
6721 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one); | |
6722 if (EXPR_P (max)) | |
6723 TREE_NO_WARNING (max) = 1; | |
6724 } | |
6725 } | |
6726 else if (cond_code == GE_EXPR || cond_code == GT_EXPR) | |
6727 { | |
6728 /* This should not be positive infinity; there is no overflow | |
6729 here. */ | |
6730 max = TYPE_MAX_VALUE (TREE_TYPE (op0)); | |
6731 | |
6732 min = op1; | |
6733 if (cond_code == GT_EXPR && !is_overflow_infinity (min)) | |
6734 { | |
6735 tree one = build_int_cst (TREE_TYPE (op0), 1); | |
6736 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one); | |
6737 if (EXPR_P (min)) | |
6738 TREE_NO_WARNING (min) = 1; | |
6739 } | |
6740 } | |
6741 | |
6742 /* Now refine the minimum and maximum values using any | |
6743 value range information we have for op0. */ | |
6744 if (min && max) | |
6745 { | |
6746 if (compare_values (vr->min, min) == -1) | |
6747 min = min; | |
6748 else | |
6749 min = vr->min; | |
6750 if (compare_values (vr->max, max) == 1) | |
6751 max = max; | |
6752 else | |
6753 max = vr->max; | |
6754 | |
6755 /* If the new min/max values have converged to a single value, | |
6756 then there is only one value which can satisfy the condition, | |
6757 return that value. */ | |
6758 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min)) | |
6759 return min; | |
6760 } | |
6761 return NULL; | |
6762 } | |
6763 | |
6764 /* Simplify a conditional using a relational operator to an equality | |
6765 test if the range information indicates only one value can satisfy | |
6766 the original conditional. */ | |
6767 | |
6768 static bool | |
6769 simplify_cond_using_ranges (gimple stmt) | |
6770 { | |
6771 tree op0 = gimple_cond_lhs (stmt); | |
6772 tree op1 = gimple_cond_rhs (stmt); | |
6773 enum tree_code cond_code = gimple_cond_code (stmt); | |
6774 | |
6775 if (cond_code != NE_EXPR | |
6776 && cond_code != EQ_EXPR | |
6777 && TREE_CODE (op0) == SSA_NAME | |
6778 && INTEGRAL_TYPE_P (TREE_TYPE (op0)) | |
6779 && is_gimple_min_invariant (op1)) | |
6780 { | |
6781 value_range_t *vr = get_value_range (op0); | |
6782 | |
6783 /* If we have range information for OP0, then we might be | |
6784 able to simplify this conditional. */ | |
6785 if (vr->type == VR_RANGE) | |
6786 { | |
6787 tree new_tree = test_for_singularity (cond_code, op0, op1, vr); | |
6788 | |
6789 if (new_tree) | |
6790 { | |
6791 if (dump_file) | |
6792 { | |
6793 fprintf (dump_file, "Simplified relational "); | |
6794 print_gimple_stmt (dump_file, stmt, 0, 0); | |
6795 fprintf (dump_file, " into "); | |
6796 } | |
6797 | |
6798 gimple_cond_set_code (stmt, EQ_EXPR); | |
6799 gimple_cond_set_lhs (stmt, op0); | |
6800 gimple_cond_set_rhs (stmt, new_tree); | |
6801 | |
6802 update_stmt (stmt); | |
6803 | |
6804 if (dump_file) | |
6805 { | |
6806 print_gimple_stmt (dump_file, stmt, 0, 0); | |
6807 fprintf (dump_file, "\n"); | |
6808 } | |
6809 | |
6810 return true; | |
6811 } | |
6812 | |
6813 /* Try again after inverting the condition. We only deal | |
6814 with integral types here, so no need to worry about | |
6815 issues with inverting FP comparisons. */ | |
6816 cond_code = invert_tree_comparison (cond_code, false); | |
6817 new_tree = test_for_singularity (cond_code, op0, op1, vr); | |
6818 | |
6819 if (new_tree) | |
6820 { | |
6821 if (dump_file) | |
6822 { | |
6823 fprintf (dump_file, "Simplified relational "); | |
6824 print_gimple_stmt (dump_file, stmt, 0, 0); | |
6825 fprintf (dump_file, " into "); | |
6826 } | |
6827 | |
6828 gimple_cond_set_code (stmt, NE_EXPR); | |
6829 gimple_cond_set_lhs (stmt, op0); | |
6830 gimple_cond_set_rhs (stmt, new_tree); | |
6831 | |
6832 update_stmt (stmt); | |
6833 | |
6834 if (dump_file) | |
6835 { | |
6836 print_gimple_stmt (dump_file, stmt, 0, 0); | |
6837 fprintf (dump_file, "\n"); | |
6838 } | |
6839 | |
6840 return true; | |
6841 } | |
6842 } | |
6843 } | |
6844 | |
6845 return false; | |
6846 } | |
6847 | |
6848 /* Simplify a switch statement using the value range of the switch | |
6849 argument. */ | |
6850 | |
6851 static bool | |
6852 simplify_switch_using_ranges (gimple stmt) | |
6853 { | |
6854 tree op = gimple_switch_index (stmt); | |
6855 value_range_t *vr; | |
6856 bool take_default; | |
6857 edge e; | |
6858 edge_iterator ei; | |
6859 size_t i = 0, j = 0, n, n2; | |
6860 tree vec2; | |
6861 switch_update su; | |
6862 | |
6863 if (TREE_CODE (op) != SSA_NAME) | |
6864 return false; | |
6865 | |
6866 vr = get_value_range (op); | |
6867 | |
6868 /* We can only handle integer ranges. */ | |
6869 if (vr->type != VR_RANGE | |
6870 || symbolic_range_p (vr)) | |
6871 return false; | |
6872 | |
6873 /* Find case label for min/max of the value range. */ | |
6874 n = gimple_switch_num_labels (stmt); | |
6875 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j); | |
6876 | |
6877 /* Bail out if this is just all edges taken. */ | |
6878 if (i == 1 | |
6879 && j == n - 1 | |
6880 && take_default) | |
6881 return false; | |
6882 | |
6883 /* Build a new vector of taken case labels. */ | |
6884 vec2 = make_tree_vec (j - i + 1 + (int)take_default); | |
6885 n2 = 0; | |
6886 | |
6887 /* Add the default edge, if necessary. */ | |
6888 if (take_default) | |
6889 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt); | |
6890 | |
6891 for (; i <= j; ++i, ++n2) | |
6892 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i); | |
6893 | |
6894 /* Mark needed edges. */ | |
6895 for (i = 0; i < n2; ++i) | |
6896 { | |
6897 e = find_edge (gimple_bb (stmt), | |
6898 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i)))); | |
6899 e->aux = (void *)-1; | |
6900 } | |
6901 | |
6902 /* Queue not needed edges for later removal. */ | |
6903 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs) | |
6904 { | |
6905 if (e->aux == (void *)-1) | |
6906 { | |
6907 e->aux = NULL; | |
6908 continue; | |
6909 } | |
6910 | |
6911 if (dump_file && (dump_flags & TDF_DETAILS)) | |
6912 { | |
6913 fprintf (dump_file, "removing unreachable case label\n"); | |
6914 } | |
6915 VEC_safe_push (edge, heap, to_remove_edges, e); | |
6916 } | |
6917 | |
6918 /* And queue an update for the stmt. */ | |
6919 su.stmt = stmt; | |
6920 su.vec = vec2; | |
6921 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su); | |
6922 return false; | |
6923 } | |
6924 | |
6925 /* Simplify STMT using ranges if possible. */ | |
6926 | |
6927 bool | |
6928 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi) | |
6929 { | |
6930 gimple stmt = gsi_stmt (*gsi); | |
6931 if (is_gimple_assign (stmt)) | |
6932 { | |
6933 enum tree_code rhs_code = gimple_assign_rhs_code (stmt); | |
6934 | |
6935 switch (rhs_code) | |
6936 { | |
6937 case EQ_EXPR: | |
6938 case NE_EXPR: | |
6939 case TRUTH_NOT_EXPR: | |
6940 case TRUTH_AND_EXPR: | |
6941 case TRUTH_OR_EXPR: | |
6942 case TRUTH_XOR_EXPR: | |
6943 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR | |
6944 or identity if the RHS is zero or one, and the LHS are known | |
6945 to be boolean values. Transform all TRUTH_*_EXPR into | |
6946 BIT_*_EXPR if both arguments are known to be boolean values. */ | |
6947 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))) | |
6948 return simplify_truth_ops_using_ranges (gsi, stmt); | |
6949 break; | |
6950 | |
6951 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR | |
6952 and BIT_AND_EXPR respectively if the first operand is greater | |
6953 than zero and the second operand is an exact power of two. */ | |
6954 case TRUNC_DIV_EXPR: | |
6955 case TRUNC_MOD_EXPR: | |
6956 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))) | |
6957 && integer_pow2p (gimple_assign_rhs2 (stmt))) | |
6958 return simplify_div_or_mod_using_ranges (stmt); | |
6959 break; | |
6960 | |
6961 /* Transform ABS (X) into X or -X as appropriate. */ | |
6962 case ABS_EXPR: | |
6963 if (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME | |
6964 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))) | |
6965 return simplify_abs_using_ranges (stmt); | |
6966 break; | |
6967 | |
6968 default: | |
6969 break; | |
6970 } | |
6971 } | |
6972 else if (gimple_code (stmt) == GIMPLE_COND) | |
6973 return simplify_cond_using_ranges (stmt); | |
6974 else if (gimple_code (stmt) == GIMPLE_SWITCH) | |
6975 return simplify_switch_using_ranges (stmt); | |
6976 | |
6977 return false; | |
6978 } | |
6979 | |
6980 /* Stack of dest,src equivalency pairs that need to be restored after | |
6981 each attempt to thread a block's incoming edge to an outgoing edge. | |
6982 | |
6983 A NULL entry is used to mark the end of pairs which need to be | |
6984 restored. */ | |
6985 static VEC(tree,heap) *stack; | |
6986 | |
6987 /* A trivial wrapper so that we can present the generic jump threading | |
6988 code with a simple API for simplifying statements. STMT is the | |
6989 statement we want to simplify, WITHIN_STMT provides the location | |
6990 for any overflow warnings. */ | |
6991 | |
6992 static tree | |
6993 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt) | |
6994 { | |
6995 /* We only use VRP information to simplify conditionals. This is | |
6996 overly conservative, but it's unclear if doing more would be | |
6997 worth the compile time cost. */ | |
6998 if (gimple_code (stmt) != GIMPLE_COND) | |
6999 return NULL; | |
7000 | |
7001 return vrp_evaluate_conditional (gimple_cond_code (stmt), | |
7002 gimple_cond_lhs (stmt), | |
7003 gimple_cond_rhs (stmt), within_stmt); | |
7004 } | |
7005 | |
7006 /* Blocks which have more than one predecessor and more than | |
7007 one successor present jump threading opportunities, i.e., | |
7008 when the block is reached from a specific predecessor, we | |
7009 may be able to determine which of the outgoing edges will | |
7010 be traversed. When this optimization applies, we are able | |
7011 to avoid conditionals at runtime and we may expose secondary | |
7012 optimization opportunities. | |
7013 | |
7014 This routine is effectively a driver for the generic jump | |
7015 threading code. It basically just presents the generic code | |
7016 with edges that may be suitable for jump threading. | |
7017 | |
7018 Unlike DOM, we do not iterate VRP if jump threading was successful. | |
7019 While iterating may expose new opportunities for VRP, it is expected | |
7020 those opportunities would be very limited and the compile time cost | |
7021 to expose those opportunities would be significant. | |
7022 | |
7023 As jump threading opportunities are discovered, they are registered | |
7024 for later realization. */ | |
7025 | |
7026 static void | |
7027 identify_jump_threads (void) | |
7028 { | |
7029 basic_block bb; | |
7030 gimple dummy; | |
7031 int i; | |
7032 edge e; | |
7033 | |
7034 /* Ugh. When substituting values earlier in this pass we can | |
7035 wipe the dominance information. So rebuild the dominator | |
7036 information as we need it within the jump threading code. */ | |
7037 calculate_dominance_info (CDI_DOMINATORS); | |
7038 | |
7039 /* We do not allow VRP information to be used for jump threading | |
7040 across a back edge in the CFG. Otherwise it becomes too | |
7041 difficult to avoid eliminating loop exit tests. Of course | |
7042 EDGE_DFS_BACK is not accurate at this time so we have to | |
7043 recompute it. */ | |
7044 mark_dfs_back_edges (); | |
7045 | |
7046 /* Do not thread across edges we are about to remove. Just marking | |
7047 them as EDGE_DFS_BACK will do. */ | |
7048 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i) | |
7049 e->flags |= EDGE_DFS_BACK; | |
7050 | |
7051 /* Allocate our unwinder stack to unwind any temporary equivalences | |
7052 that might be recorded. */ | |
7053 stack = VEC_alloc (tree, heap, 20); | |
7054 | |
7055 /* To avoid lots of silly node creation, we create a single | |
7056 conditional and just modify it in-place when attempting to | |
7057 thread jumps. */ | |
7058 dummy = gimple_build_cond (EQ_EXPR, | |
7059 integer_zero_node, integer_zero_node, | |
7060 NULL, NULL); | |
7061 | |
7062 /* Walk through all the blocks finding those which present a | |
7063 potential jump threading opportunity. We could set this up | |
7064 as a dominator walker and record data during the walk, but | |
7065 I doubt it's worth the effort for the classes of jump | |
7066 threading opportunities we are trying to identify at this | |
7067 point in compilation. */ | |
7068 FOR_EACH_BB (bb) | |
7069 { | |
7070 gimple last; | |
7071 | |
7072 /* If the generic jump threading code does not find this block | |
7073 interesting, then there is nothing to do. */ | |
7074 if (! potentially_threadable_block (bb)) | |
7075 continue; | |
7076 | |
7077 /* We only care about blocks ending in a COND_EXPR. While there | |
7078 may be some value in handling SWITCH_EXPR here, I doubt it's | |
7079 terribly important. */ | |
7080 last = gsi_stmt (gsi_last_bb (bb)); | |
7081 if (gimple_code (last) != GIMPLE_COND) | |
7082 continue; | |
7083 | |
7084 /* We're basically looking for any kind of conditional with | |
7085 integral type arguments. */ | |
7086 if (TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME | |
7087 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last))) | |
7088 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME | |
7089 || is_gimple_min_invariant (gimple_cond_rhs (last))) | |
7090 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_rhs (last)))) | |
7091 { | |
7092 edge_iterator ei; | |
7093 | |
7094 /* We've got a block with multiple predecessors and multiple | |
7095 successors which also ends in a suitable conditional. For | |
7096 each predecessor, see if we can thread it to a specific | |
7097 successor. */ | |
7098 FOR_EACH_EDGE (e, ei, bb->preds) | |
7099 { | |
7100 /* Do not thread across back edges or abnormal edges | |
7101 in the CFG. */ | |
7102 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX)) | |
7103 continue; | |
7104 | |
7105 thread_across_edge (dummy, e, true, &stack, | |
7106 simplify_stmt_for_jump_threading); | |
7107 } | |
7108 } | |
7109 } | |
7110 | |
7111 /* We do not actually update the CFG or SSA graphs at this point as | |
7112 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet | |
7113 handle ASSERT_EXPRs gracefully. */ | |
7114 } | |
7115 | |
7116 /* We identified all the jump threading opportunities earlier, but could | |
7117 not transform the CFG at that time. This routine transforms the | |
7118 CFG and arranges for the dominator tree to be rebuilt if necessary. | |
7119 | |
7120 Note the SSA graph update will occur during the normal TODO | |
7121 processing by the pass manager. */ | |
7122 static void | |
7123 finalize_jump_threads (void) | |
7124 { | |
7125 thread_through_all_blocks (false); | |
7126 VEC_free (tree, heap, stack); | |
7127 } | |
7128 | |
7129 | |
7130 /* Traverse all the blocks folding conditionals with known ranges. */ | |
7131 | |
7132 static void | |
7133 vrp_finalize (void) | |
7134 { | |
7135 size_t i; | |
7136 prop_value_t *single_val_range; | |
7137 bool do_value_subst_p; | |
7138 | |
7139 if (dump_file) | |
7140 { | |
7141 fprintf (dump_file, "\nValue ranges after VRP:\n\n"); | |
7142 dump_all_value_ranges (dump_file); | |
7143 fprintf (dump_file, "\n"); | |
7144 } | |
7145 | |
7146 /* We may have ended with ranges that have exactly one value. Those | |
7147 values can be substituted as any other copy/const propagated | |
7148 value using substitute_and_fold. */ | |
7149 single_val_range = XCNEWVEC (prop_value_t, num_ssa_names); | |
7150 | |
7151 do_value_subst_p = false; | |
7152 for (i = 0; i < num_ssa_names; i++) | |
7153 if (vr_value[i] | |
7154 && vr_value[i]->type == VR_RANGE | |
7155 && vr_value[i]->min == vr_value[i]->max) | |
7156 { | |
7157 single_val_range[i].value = vr_value[i]->min; | |
7158 do_value_subst_p = true; | |
7159 } | |
7160 | |
7161 if (!do_value_subst_p) | |
7162 { | |
7163 /* We found no single-valued ranges, don't waste time trying to | |
7164 do single value substitution in substitute_and_fold. */ | |
7165 free (single_val_range); | |
7166 single_val_range = NULL; | |
7167 } | |
7168 | |
7169 substitute_and_fold (single_val_range, true); | |
7170 | |
7171 if (warn_array_bounds) | |
7172 check_all_array_refs (); | |
7173 | |
7174 /* We must identify jump threading opportunities before we release | |
7175 the datastructures built by VRP. */ | |
7176 identify_jump_threads (); | |
7177 | |
7178 /* Free allocated memory. */ | |
7179 for (i = 0; i < num_ssa_names; i++) | |
7180 if (vr_value[i]) | |
7181 { | |
7182 BITMAP_FREE (vr_value[i]->equiv); | |
7183 free (vr_value[i]); | |
7184 } | |
7185 | |
7186 free (single_val_range); | |
7187 free (vr_value); | |
7188 free (vr_phi_edge_counts); | |
7189 | |
7190 /* So that we can distinguish between VRP data being available | |
7191 and not available. */ | |
7192 vr_value = NULL; | |
7193 vr_phi_edge_counts = NULL; | |
7194 } | |
7195 | |
7196 | |
7197 /* Main entry point to VRP (Value Range Propagation). This pass is | |
7198 loosely based on J. R. C. Patterson, ``Accurate Static Branch | |
7199 Prediction by Value Range Propagation,'' in SIGPLAN Conference on | |
7200 Programming Language Design and Implementation, pp. 67-78, 1995. | |
7201 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html | |
7202 | |
7203 This is essentially an SSA-CCP pass modified to deal with ranges | |
7204 instead of constants. | |
7205 | |
7206 While propagating ranges, we may find that two or more SSA name | |
7207 have equivalent, though distinct ranges. For instance, | |
7208 | |
7209 1 x_9 = p_3->a; | |
7210 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0> | |
7211 3 if (p_4 == q_2) | |
7212 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>; | |
7213 5 endif | |
7214 6 if (q_2) | |
7215 | |
7216 In the code above, pointer p_5 has range [q_2, q_2], but from the | |
7217 code we can also determine that p_5 cannot be NULL and, if q_2 had | |
7218 a non-varying range, p_5's range should also be compatible with it. | |
7219 | |
7220 These equivalences are created by two expressions: ASSERT_EXPR and | |
7221 copy operations. Since p_5 is an assertion on p_4, and p_4 was the | |
7222 result of another assertion, then we can use the fact that p_5 and | |
7223 p_4 are equivalent when evaluating p_5's range. | |
7224 | |
7225 Together with value ranges, we also propagate these equivalences | |
7226 between names so that we can take advantage of information from | |
7227 multiple ranges when doing final replacement. Note that this | |
7228 equivalency relation is transitive but not symmetric. | |
7229 | |
7230 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we | |
7231 cannot assert that q_2 is equivalent to p_5 because q_2 may be used | |
7232 in contexts where that assertion does not hold (e.g., in line 6). | |
7233 | |
7234 TODO, the main difference between this pass and Patterson's is that | |
7235 we do not propagate edge probabilities. We only compute whether | |
7236 edges can be taken or not. That is, instead of having a spectrum | |
7237 of jump probabilities between 0 and 1, we only deal with 0, 1 and | |
7238 DON'T KNOW. In the future, it may be worthwhile to propagate | |
7239 probabilities to aid branch prediction. */ | |
7240 | |
7241 static unsigned int | |
7242 execute_vrp (void) | |
7243 { | |
7244 int i; | |
7245 edge e; | |
7246 switch_update *su; | |
7247 | |
7248 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS); | |
7249 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa); | |
7250 scev_initialize (); | |
7251 | |
7252 insert_range_assertions (); | |
7253 | |
7254 to_remove_edges = VEC_alloc (edge, heap, 10); | |
7255 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5); | |
7256 | |
7257 vrp_initialize (); | |
7258 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node); | |
7259 vrp_finalize (); | |
7260 | |
7261 /* ASSERT_EXPRs must be removed before finalizing jump threads | |
7262 as finalizing jump threads calls the CFG cleanup code which | |
7263 does not properly handle ASSERT_EXPRs. */ | |
7264 remove_range_assertions (); | |
7265 | |
7266 /* If we exposed any new variables, go ahead and put them into | |
7267 SSA form now, before we handle jump threading. This simplifies | |
7268 interactions between rewriting of _DECL nodes into SSA form | |
7269 and rewriting SSA_NAME nodes into SSA form after block | |
7270 duplication and CFG manipulation. */ | |
7271 update_ssa (TODO_update_ssa); | |
7272 | |
7273 finalize_jump_threads (); | |
7274 | |
7275 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the | |
7276 CFG in a broken state and requires a cfg_cleanup run. */ | |
7277 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i) | |
7278 remove_edge (e); | |
7279 /* Update SWITCH_EXPR case label vector. */ | |
7280 for (i = 0; VEC_iterate (switch_update, to_update_switch_stmts, i, su); ++i) | |
7281 { | |
7282 size_t j; | |
7283 size_t n = TREE_VEC_LENGTH (su->vec); | |
7284 tree label; | |
7285 gimple_switch_set_num_labels (su->stmt, n); | |
7286 for (j = 0; j < n; j++) | |
7287 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j)); | |
7288 /* As we may have replaced the default label with a regular one | |
7289 make sure to make it a real default label again. This ensures | |
7290 optimal expansion. */ | |
7291 label = gimple_switch_default_label (su->stmt); | |
7292 CASE_LOW (label) = NULL_TREE; | |
7293 CASE_HIGH (label) = NULL_TREE; | |
7294 } | |
7295 | |
7296 if (VEC_length (edge, to_remove_edges) > 0) | |
7297 free_dominance_info (CDI_DOMINATORS); | |
7298 | |
7299 VEC_free (edge, heap, to_remove_edges); | |
7300 VEC_free (switch_update, heap, to_update_switch_stmts); | |
7301 | |
7302 scev_finalize (); | |
7303 loop_optimizer_finalize (); | |
7304 return 0; | |
7305 } | |
7306 | |
7307 static bool | |
7308 gate_vrp (void) | |
7309 { | |
7310 return flag_tree_vrp != 0; | |
7311 } | |
7312 | |
7313 struct gimple_opt_pass pass_vrp = | |
7314 { | |
7315 { | |
7316 GIMPLE_PASS, | |
7317 "vrp", /* name */ | |
7318 gate_vrp, /* gate */ | |
7319 execute_vrp, /* execute */ | |
7320 NULL, /* sub */ | |
7321 NULL, /* next */ | |
7322 0, /* static_pass_number */ | |
7323 TV_TREE_VRP, /* tv_id */ | |
7324 PROP_ssa | PROP_alias, /* properties_required */ | |
7325 0, /* properties_provided */ | |
7326 0, /* properties_destroyed */ | |
7327 0, /* todo_flags_start */ | |
7328 TODO_cleanup_cfg | |
7329 | TODO_ggc_collect | |
7330 | TODO_verify_ssa | |
7331 | TODO_dump_func | |
7332 | TODO_update_ssa /* todo_flags_finish */ | |
7333 } | |
7334 }; |