Merge branch 'vendor/GCC47'
[dragonfly.git] / contrib / gcc-4.7 / gcc / tree-vrp.c
CommitLineData
e4b17023
JM
1/* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
3 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>.
5
6This file is part of GCC.
7
8GCC is free software; you can redistribute it and/or modify
9it under the terms of the GNU General Public License as published by
10the Free Software Foundation; either version 3, or (at your option)
11any later version.
12
13GCC is distributed in the hope that it will be useful,
14but WITHOUT ANY WARRANTY; without even the implied warranty of
15MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16GNU General Public License for more details.
17
18You should have received a copy of the GNU General Public License
19along with GCC; see the file COPYING3. If not see
20<http://www.gnu.org/licenses/>. */
21
22#include "config.h"
23#include "system.h"
24#include "coretypes.h"
25#include "tm.h"
26#include "ggc.h"
27#include "flags.h"
28#include "tree.h"
29#include "basic-block.h"
30#include "tree-flow.h"
31#include "tree-pass.h"
32#include "tree-dump.h"
33#include "timevar.h"
34#include "tree-pretty-print.h"
35#include "gimple-pretty-print.h"
36#include "diagnostic-core.h"
37#include "intl.h"
38#include "cfgloop.h"
39#include "tree-scalar-evolution.h"
40#include "tree-ssa-propagate.h"
41#include "tree-chrec.h"
42#include "gimple-fold.h"
43#include "expr.h"
44#include "optabs.h"
45
46
47/* Type of value ranges. See value_range_d for a description of these
48 types. */
49enum value_range_type { VR_UNDEFINED, VR_RANGE, VR_ANTI_RANGE, VR_VARYING };
50
51/* Range of values that can be associated with an SSA_NAME after VRP
52 has executed. */
53struct value_range_d
54{
55 /* Lattice value represented by this range. */
56 enum value_range_type type;
57
58 /* Minimum and maximum values represented by this range. These
59 values should be interpreted as follows:
60
61 - If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must
62 be NULL.
63
64 - If TYPE == VR_RANGE then MIN holds the minimum value and
65 MAX holds the maximum value of the range [MIN, MAX].
66
67 - If TYPE == ANTI_RANGE the variable is known to NOT
68 take any values in the range [MIN, MAX]. */
69 tree min;
70 tree max;
71
72 /* Set of SSA names whose value ranges are equivalent to this one.
73 This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE. */
74 bitmap equiv;
75};
76
77typedef struct value_range_d value_range_t;
78
79/* Set of SSA names found live during the RPO traversal of the function
80 for still active basic-blocks. */
81static sbitmap *live;
82
83/* Return true if the SSA name NAME is live on the edge E. */
84
85static bool
86live_on_edge (edge e, tree name)
87{
88 return (live[e->dest->index]
89 && TEST_BIT (live[e->dest->index], SSA_NAME_VERSION (name)));
90}
91
92/* Local functions. */
93static int compare_values (tree val1, tree val2);
94static int compare_values_warnv (tree val1, tree val2, bool *);
95static void vrp_meet (value_range_t *, value_range_t *);
96static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code,
97 tree, tree, bool, bool *,
98 bool *);
99
100/* Location information for ASSERT_EXPRs. Each instance of this
101 structure describes an ASSERT_EXPR for an SSA name. Since a single
102 SSA name may have more than one assertion associated with it, these
103 locations are kept in a linked list attached to the corresponding
104 SSA name. */
105struct assert_locus_d
106{
107 /* Basic block where the assertion would be inserted. */
108 basic_block bb;
109
110 /* Some assertions need to be inserted on an edge (e.g., assertions
111 generated by COND_EXPRs). In those cases, BB will be NULL. */
112 edge e;
113
114 /* Pointer to the statement that generated this assertion. */
115 gimple_stmt_iterator si;
116
117 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
118 enum tree_code comp_code;
119
120 /* Value being compared against. */
121 tree val;
122
123 /* Expression to compare. */
124 tree expr;
125
126 /* Next node in the linked list. */
127 struct assert_locus_d *next;
128};
129
130typedef struct assert_locus_d *assert_locus_t;
131
132/* If bit I is present, it means that SSA name N_i has a list of
133 assertions that should be inserted in the IL. */
134static bitmap need_assert_for;
135
136/* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
137 holds a list of ASSERT_LOCUS_T nodes that describe where
138 ASSERT_EXPRs for SSA name N_I should be inserted. */
139static assert_locus_t *asserts_for;
140
141/* Value range array. After propagation, VR_VALUE[I] holds the range
142 of values that SSA name N_I may take. */
143static unsigned num_vr_values;
144static value_range_t **vr_value;
145static bool values_propagated;
146
147/* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
148 number of executable edges we saw the last time we visited the
149 node. */
150static int *vr_phi_edge_counts;
151
152typedef struct {
153 gimple stmt;
154 tree vec;
155} switch_update;
156
157static VEC (edge, heap) *to_remove_edges;
158DEF_VEC_O(switch_update);
159DEF_VEC_ALLOC_O(switch_update, heap);
160static VEC (switch_update, heap) *to_update_switch_stmts;
161
162
163/* Return the maximum value for TYPE. */
164
165static inline tree
166vrp_val_max (const_tree type)
167{
168 if (!INTEGRAL_TYPE_P (type))
169 return NULL_TREE;
170
171 return TYPE_MAX_VALUE (type);
172}
173
174/* Return the minimum value for TYPE. */
175
176static inline tree
177vrp_val_min (const_tree type)
178{
179 if (!INTEGRAL_TYPE_P (type))
180 return NULL_TREE;
181
182 return TYPE_MIN_VALUE (type);
183}
184
185/* Return whether VAL is equal to the maximum value of its type. This
186 will be true for a positive overflow infinity. We can't do a
187 simple equality comparison with TYPE_MAX_VALUE because C typedefs
188 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
189 to the integer constant with the same value in the type. */
190
191static inline bool
192vrp_val_is_max (const_tree val)
193{
194 tree type_max = vrp_val_max (TREE_TYPE (val));
195 return (val == type_max
196 || (type_max != NULL_TREE
197 && operand_equal_p (val, type_max, 0)));
198}
199
200/* Return whether VAL is equal to the minimum value of its type. This
201 will be true for a negative overflow infinity. */
202
203static inline bool
204vrp_val_is_min (const_tree val)
205{
206 tree type_min = vrp_val_min (TREE_TYPE (val));
207 return (val == type_min
208 || (type_min != NULL_TREE
209 && operand_equal_p (val, type_min, 0)));
210}
211
212
213/* Return whether TYPE should use an overflow infinity distinct from
214 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
215 represent a signed overflow during VRP computations. An infinity
216 is distinct from a half-range, which will go from some number to
217 TYPE_{MIN,MAX}_VALUE. */
218
219static inline bool
220needs_overflow_infinity (const_tree type)
221{
222 return INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type);
223}
224
225/* Return whether TYPE can support our overflow infinity
226 representation: we use the TREE_OVERFLOW flag, which only exists
227 for constants. If TYPE doesn't support this, we don't optimize
228 cases which would require signed overflow--we drop them to
229 VARYING. */
230
231static inline bool
232supports_overflow_infinity (const_tree type)
233{
234 tree min = vrp_val_min (type), max = vrp_val_max (type);
235#ifdef ENABLE_CHECKING
236 gcc_assert (needs_overflow_infinity (type));
237#endif
238 return (min != NULL_TREE
239 && CONSTANT_CLASS_P (min)
240 && max != NULL_TREE
241 && CONSTANT_CLASS_P (max));
242}
243
244/* VAL is the maximum or minimum value of a type. Return a
245 corresponding overflow infinity. */
246
247static inline tree
248make_overflow_infinity (tree val)
249{
250 gcc_checking_assert (val != NULL_TREE && CONSTANT_CLASS_P (val));
251 val = copy_node (val);
252 TREE_OVERFLOW (val) = 1;
253 return val;
254}
255
256/* Return a negative overflow infinity for TYPE. */
257
258static inline tree
259negative_overflow_infinity (tree type)
260{
261 gcc_checking_assert (supports_overflow_infinity (type));
262 return make_overflow_infinity (vrp_val_min (type));
263}
264
265/* Return a positive overflow infinity for TYPE. */
266
267static inline tree
268positive_overflow_infinity (tree type)
269{
270 gcc_checking_assert (supports_overflow_infinity (type));
271 return make_overflow_infinity (vrp_val_max (type));
272}
273
274/* Return whether VAL is a negative overflow infinity. */
275
276static inline bool
277is_negative_overflow_infinity (const_tree val)
278{
279 return (needs_overflow_infinity (TREE_TYPE (val))
280 && CONSTANT_CLASS_P (val)
281 && TREE_OVERFLOW (val)
282 && vrp_val_is_min (val));
283}
284
285/* Return whether VAL is a positive overflow infinity. */
286
287static inline bool
288is_positive_overflow_infinity (const_tree val)
289{
290 return (needs_overflow_infinity (TREE_TYPE (val))
291 && CONSTANT_CLASS_P (val)
292 && TREE_OVERFLOW (val)
293 && vrp_val_is_max (val));
294}
295
296/* Return whether VAL is a positive or negative overflow infinity. */
297
298static inline bool
299is_overflow_infinity (const_tree val)
300{
301 return (needs_overflow_infinity (TREE_TYPE (val))
302 && CONSTANT_CLASS_P (val)
303 && TREE_OVERFLOW (val)
304 && (vrp_val_is_min (val) || vrp_val_is_max (val)));
305}
306
307/* Return whether STMT has a constant rhs that is_overflow_infinity. */
308
309static inline bool
310stmt_overflow_infinity (gimple stmt)
311{
312 if (is_gimple_assign (stmt)
313 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) ==
314 GIMPLE_SINGLE_RHS)
315 return is_overflow_infinity (gimple_assign_rhs1 (stmt));
316 return false;
317}
318
319/* If VAL is now an overflow infinity, return VAL. Otherwise, return
320 the same value with TREE_OVERFLOW clear. This can be used to avoid
321 confusing a regular value with an overflow value. */
322
323static inline tree
324avoid_overflow_infinity (tree val)
325{
326 if (!is_overflow_infinity (val))
327 return val;
328
329 if (vrp_val_is_max (val))
330 return vrp_val_max (TREE_TYPE (val));
331 else
332 {
333 gcc_checking_assert (vrp_val_is_min (val));
334 return vrp_val_min (TREE_TYPE (val));
335 }
336}
337
338
339/* Return true if ARG is marked with the nonnull attribute in the
340 current function signature. */
341
342static bool
343nonnull_arg_p (const_tree arg)
344{
345 tree t, attrs, fntype;
346 unsigned HOST_WIDE_INT arg_num;
347
348 gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg)));
349
350 /* The static chain decl is always non null. */
351 if (arg == cfun->static_chain_decl)
352 return true;
353
354 fntype = TREE_TYPE (current_function_decl);
355 attrs = lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype));
356
357 /* If "nonnull" wasn't specified, we know nothing about the argument. */
358 if (attrs == NULL_TREE)
359 return false;
360
361 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
362 if (TREE_VALUE (attrs) == NULL_TREE)
363 return true;
364
365 /* Get the position number for ARG in the function signature. */
366 for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
367 t;
368 t = DECL_CHAIN (t), arg_num++)
369 {
370 if (t == arg)
371 break;
372 }
373
374 gcc_assert (t == arg);
375
376 /* Now see if ARG_NUM is mentioned in the nonnull list. */
377 for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t))
378 {
379 if (compare_tree_int (TREE_VALUE (t), arg_num) == 0)
380 return true;
381 }
382
383 return false;
384}
385
386
387/* Set value range VR to VR_VARYING. */
388
389static inline void
390set_value_range_to_varying (value_range_t *vr)
391{
392 vr->type = VR_VARYING;
393 vr->min = vr->max = NULL_TREE;
394 if (vr->equiv)
395 bitmap_clear (vr->equiv);
396}
397
398
399/* Set value range VR to {T, MIN, MAX, EQUIV}. */
400
401static void
402set_value_range (value_range_t *vr, enum value_range_type t, tree min,
403 tree max, bitmap equiv)
404{
405#if defined ENABLE_CHECKING
406 /* Check the validity of the range. */
407 if (t == VR_RANGE || t == VR_ANTI_RANGE)
408 {
409 int cmp;
410
411 gcc_assert (min && max);
412
413 if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE)
414 gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max));
415
416 cmp = compare_values (min, max);
417 gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
418
419 if (needs_overflow_infinity (TREE_TYPE (min)))
420 gcc_assert (!is_overflow_infinity (min)
421 || !is_overflow_infinity (max));
422 }
423
424 if (t == VR_UNDEFINED || t == VR_VARYING)
425 gcc_assert (min == NULL_TREE && max == NULL_TREE);
426
427 if (t == VR_UNDEFINED || t == VR_VARYING)
428 gcc_assert (equiv == NULL || bitmap_empty_p (equiv));
429#endif
430
431 vr->type = t;
432 vr->min = min;
433 vr->max = max;
434
435 /* Since updating the equivalence set involves deep copying the
436 bitmaps, only do it if absolutely necessary. */
437 if (vr->equiv == NULL
438 && equiv != NULL)
439 vr->equiv = BITMAP_ALLOC (NULL);
440
441 if (equiv != vr->equiv)
442 {
443 if (equiv && !bitmap_empty_p (equiv))
444 bitmap_copy (vr->equiv, equiv);
445 else
446 bitmap_clear (vr->equiv);
447 }
448}
449
450
451/* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
452 This means adjusting T, MIN and MAX representing the case of a
453 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
454 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
455 In corner cases where MAX+1 or MIN-1 wraps this will fall back
456 to varying.
457 This routine exists to ease canonicalization in the case where we
458 extract ranges from var + CST op limit. */
459
460static void
461set_and_canonicalize_value_range (value_range_t *vr, enum value_range_type t,
462 tree min, tree max, bitmap equiv)
463{
464 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */
465 if ((t != VR_RANGE
466 && t != VR_ANTI_RANGE)
467 || TREE_CODE (min) != INTEGER_CST
468 || TREE_CODE (max) != INTEGER_CST)
469 {
470 set_value_range (vr, t, min, max, equiv);
471 return;
472 }
473
474 /* Wrong order for min and max, to swap them and the VR type we need
475 to adjust them. */
476 if (tree_int_cst_lt (max, min))
477 {
478 tree one = build_int_cst (TREE_TYPE (min), 1);
479 tree tmp = int_const_binop (PLUS_EXPR, max, one);
480 max = int_const_binop (MINUS_EXPR, min, one);
481 min = tmp;
482
483 /* There's one corner case, if we had [C+1, C] before we now have
484 that again. But this represents an empty value range, so drop
485 to varying in this case. */
486 if (tree_int_cst_lt (max, min))
487 {
488 set_value_range_to_varying (vr);
489 return;
490 }
491
492 t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
493 }
494
495 /* Anti-ranges that can be represented as ranges should be so. */
496 if (t == VR_ANTI_RANGE)
497 {
498 bool is_min = vrp_val_is_min (min);
499 bool is_max = vrp_val_is_max (max);
500
501 if (is_min && is_max)
502 {
503 /* We cannot deal with empty ranges, drop to varying. */
504 set_value_range_to_varying (vr);
505 return;
506 }
507 else if (is_min
508 /* As a special exception preserve non-null ranges. */
509 && !(TYPE_UNSIGNED (TREE_TYPE (min))
510 && integer_zerop (max)))
511 {
512 tree one = build_int_cst (TREE_TYPE (max), 1);
513 min = int_const_binop (PLUS_EXPR, max, one);
514 max = vrp_val_max (TREE_TYPE (max));
515 t = VR_RANGE;
516 }
517 else if (is_max)
518 {
519 tree one = build_int_cst (TREE_TYPE (min), 1);
520 max = int_const_binop (MINUS_EXPR, min, one);
521 min = vrp_val_min (TREE_TYPE (min));
522 t = VR_RANGE;
523 }
524 }
525
526 set_value_range (vr, t, min, max, equiv);
527}
528
529/* Copy value range FROM into value range TO. */
530
531static inline void
532copy_value_range (value_range_t *to, value_range_t *from)
533{
534 set_value_range (to, from->type, from->min, from->max, from->equiv);
535}
536
537/* Set value range VR to a single value. This function is only called
538 with values we get from statements, and exists to clear the
539 TREE_OVERFLOW flag so that we don't think we have an overflow
540 infinity when we shouldn't. */
541
542static inline void
543set_value_range_to_value (value_range_t *vr, tree val, bitmap equiv)
544{
545 gcc_assert (is_gimple_min_invariant (val));
546 val = avoid_overflow_infinity (val);
547 set_value_range (vr, VR_RANGE, val, val, equiv);
548}
549
550/* Set value range VR to a non-negative range of type TYPE.
551 OVERFLOW_INFINITY indicates whether to use an overflow infinity
552 rather than TYPE_MAX_VALUE; this should be true if we determine
553 that the range is nonnegative based on the assumption that signed
554 overflow does not occur. */
555
556static inline void
557set_value_range_to_nonnegative (value_range_t *vr, tree type,
558 bool overflow_infinity)
559{
560 tree zero;
561
562 if (overflow_infinity && !supports_overflow_infinity (type))
563 {
564 set_value_range_to_varying (vr);
565 return;
566 }
567
568 zero = build_int_cst (type, 0);
569 set_value_range (vr, VR_RANGE, zero,
570 (overflow_infinity
571 ? positive_overflow_infinity (type)
572 : TYPE_MAX_VALUE (type)),
573 vr->equiv);
574}
575
576/* Set value range VR to a non-NULL range of type TYPE. */
577
578static inline void
579set_value_range_to_nonnull (value_range_t *vr, tree type)
580{
581 tree zero = build_int_cst (type, 0);
582 set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv);
583}
584
585
586/* Set value range VR to a NULL range of type TYPE. */
587
588static inline void
589set_value_range_to_null (value_range_t *vr, tree type)
590{
591 set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv);
592}
593
594
595/* Set value range VR to a range of a truthvalue of type TYPE. */
596
597static inline void
598set_value_range_to_truthvalue (value_range_t *vr, tree type)
599{
600 if (TYPE_PRECISION (type) == 1)
601 set_value_range_to_varying (vr);
602 else
603 set_value_range (vr, VR_RANGE,
604 build_int_cst (type, 0), build_int_cst (type, 1),
605 vr->equiv);
606}
607
608
609/* Set value range VR to VR_UNDEFINED. */
610
611static inline void
612set_value_range_to_undefined (value_range_t *vr)
613{
614 vr->type = VR_UNDEFINED;
615 vr->min = vr->max = NULL_TREE;
616 if (vr->equiv)
617 bitmap_clear (vr->equiv);
618}
619
620
621/* If abs (min) < abs (max), set VR to [-max, max], if
622 abs (min) >= abs (max), set VR to [-min, min]. */
623
624static void
625abs_extent_range (value_range_t *vr, tree min, tree max)
626{
627 int cmp;
628
629 gcc_assert (TREE_CODE (min) == INTEGER_CST);
630 gcc_assert (TREE_CODE (max) == INTEGER_CST);
631 gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min)));
632 gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min)));
633 min = fold_unary (ABS_EXPR, TREE_TYPE (min), min);
634 max = fold_unary (ABS_EXPR, TREE_TYPE (max), max);
635 if (TREE_OVERFLOW (min) || TREE_OVERFLOW (max))
636 {
637 set_value_range_to_varying (vr);
638 return;
639 }
640 cmp = compare_values (min, max);
641 if (cmp == -1)
642 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), max);
643 else if (cmp == 0 || cmp == 1)
644 {
645 max = min;
646 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), min);
647 }
648 else
649 {
650 set_value_range_to_varying (vr);
651 return;
652 }
653 set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL);
654}
655
656
657/* Return value range information for VAR.
658
659 If we have no values ranges recorded (ie, VRP is not running), then
660 return NULL. Otherwise create an empty range if none existed for VAR. */
661
662static value_range_t *
663get_value_range (const_tree var)
664{
665 static const struct value_range_d vr_const_varying
666 = { VR_VARYING, NULL_TREE, NULL_TREE, NULL };
667 value_range_t *vr;
668 tree sym;
669 unsigned ver = SSA_NAME_VERSION (var);
670
671 /* If we have no recorded ranges, then return NULL. */
672 if (! vr_value)
673 return NULL;
674
675 /* If we query the range for a new SSA name return an unmodifiable VARYING.
676 We should get here at most from the substitute-and-fold stage which
677 will never try to change values. */
678 if (ver >= num_vr_values)
679 return CONST_CAST (value_range_t *, &vr_const_varying);
680
681 vr = vr_value[ver];
682 if (vr)
683 return vr;
684
685 /* After propagation finished do not allocate new value-ranges. */
686 if (values_propagated)
687 return CONST_CAST (value_range_t *, &vr_const_varying);
688
689 /* Create a default value range. */
690 vr_value[ver] = vr = XCNEW (value_range_t);
691
692 /* Defer allocating the equivalence set. */
693 vr->equiv = NULL;
694
695 /* If VAR is a default definition of a parameter, the variable can
696 take any value in VAR's type. */
697 sym = SSA_NAME_VAR (var);
698 if (SSA_NAME_IS_DEFAULT_DEF (var))
699 {
700 if (TREE_CODE (sym) == PARM_DECL)
701 {
702 /* Try to use the "nonnull" attribute to create ~[0, 0]
703 anti-ranges for pointers. Note that this is only valid with
704 default definitions of PARM_DECLs. */
705 if (POINTER_TYPE_P (TREE_TYPE (sym))
706 && nonnull_arg_p (sym))
707 set_value_range_to_nonnull (vr, TREE_TYPE (sym));
708 else
709 set_value_range_to_varying (vr);
710 }
711 else if (TREE_CODE (sym) == RESULT_DECL
712 && DECL_BY_REFERENCE (sym))
713 set_value_range_to_nonnull (vr, TREE_TYPE (sym));
714 }
715
716 return vr;
717}
718
719/* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
720
721static inline bool
722vrp_operand_equal_p (const_tree val1, const_tree val2)
723{
724 if (val1 == val2)
725 return true;
726 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
727 return false;
728 if (is_overflow_infinity (val1))
729 return is_overflow_infinity (val2);
730 return true;
731}
732
733/* Return true, if the bitmaps B1 and B2 are equal. */
734
735static inline bool
736vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
737{
738 return (b1 == b2
739 || ((!b1 || bitmap_empty_p (b1))
740 && (!b2 || bitmap_empty_p (b2)))
741 || (b1 && b2
742 && bitmap_equal_p (b1, b2)));
743}
744
745/* Update the value range and equivalence set for variable VAR to
746 NEW_VR. Return true if NEW_VR is different from VAR's previous
747 value.
748
749 NOTE: This function assumes that NEW_VR is a temporary value range
750 object created for the sole purpose of updating VAR's range. The
751 storage used by the equivalence set from NEW_VR will be freed by
752 this function. Do not call update_value_range when NEW_VR
753 is the range object associated with another SSA name. */
754
755static inline bool
756update_value_range (const_tree var, value_range_t *new_vr)
757{
758 value_range_t *old_vr;
759 bool is_new;
760
761 /* Update the value range, if necessary. */
762 old_vr = get_value_range (var);
763 is_new = old_vr->type != new_vr->type
764 || !vrp_operand_equal_p (old_vr->min, new_vr->min)
765 || !vrp_operand_equal_p (old_vr->max, new_vr->max)
766 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv);
767
768 if (is_new)
769 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max,
770 new_vr->equiv);
771
772 BITMAP_FREE (new_vr->equiv);
773
774 return is_new;
775}
776
777
778/* Add VAR and VAR's equivalence set to EQUIV. This is the central
779 point where equivalence processing can be turned on/off. */
780
781static void
782add_equivalence (bitmap *equiv, const_tree var)
783{
784 unsigned ver = SSA_NAME_VERSION (var);
785 value_range_t *vr = vr_value[ver];
786
787 if (*equiv == NULL)
788 *equiv = BITMAP_ALLOC (NULL);
789 bitmap_set_bit (*equiv, ver);
790 if (vr && vr->equiv)
791 bitmap_ior_into (*equiv, vr->equiv);
792}
793
794
795/* Return true if VR is ~[0, 0]. */
796
797static inline bool
798range_is_nonnull (value_range_t *vr)
799{
800 return vr->type == VR_ANTI_RANGE
801 && integer_zerop (vr->min)
802 && integer_zerop (vr->max);
803}
804
805
806/* Return true if VR is [0, 0]. */
807
808static inline bool
809range_is_null (value_range_t *vr)
810{
811 return vr->type == VR_RANGE
812 && integer_zerop (vr->min)
813 && integer_zerop (vr->max);
814}
815
816/* Return true if max and min of VR are INTEGER_CST. It's not necessary
817 a singleton. */
818
819static inline bool
820range_int_cst_p (value_range_t *vr)
821{
822 return (vr->type == VR_RANGE
823 && TREE_CODE (vr->max) == INTEGER_CST
824 && TREE_CODE (vr->min) == INTEGER_CST
825 && !TREE_OVERFLOW (vr->max)
826 && !TREE_OVERFLOW (vr->min));
827}
828
829/* Return true if VR is a INTEGER_CST singleton. */
830
831static inline bool
832range_int_cst_singleton_p (value_range_t *vr)
833{
834 return (range_int_cst_p (vr)
835 && tree_int_cst_equal (vr->min, vr->max));
836}
837
838/* Return true if value range VR involves at least one symbol. */
839
840static inline bool
841symbolic_range_p (value_range_t *vr)
842{
843 return (!is_gimple_min_invariant (vr->min)
844 || !is_gimple_min_invariant (vr->max));
845}
846
847/* Return true if value range VR uses an overflow infinity. */
848
849static inline bool
850overflow_infinity_range_p (value_range_t *vr)
851{
852 return (vr->type == VR_RANGE
853 && (is_overflow_infinity (vr->min)
854 || is_overflow_infinity (vr->max)));
855}
856
857/* Return false if we can not make a valid comparison based on VR;
858 this will be the case if it uses an overflow infinity and overflow
859 is not undefined (i.e., -fno-strict-overflow is in effect).
860 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
861 uses an overflow infinity. */
862
863static bool
864usable_range_p (value_range_t *vr, bool *strict_overflow_p)
865{
866 gcc_assert (vr->type == VR_RANGE);
867 if (is_overflow_infinity (vr->min))
868 {
869 *strict_overflow_p = true;
870 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
871 return false;
872 }
873 if (is_overflow_infinity (vr->max))
874 {
875 *strict_overflow_p = true;
876 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
877 return false;
878 }
879 return true;
880}
881
882
883/* Return true if the result of assignment STMT is know to be non-negative.
884 If the return value is based on the assumption that signed overflow is
885 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
886 *STRICT_OVERFLOW_P.*/
887
888static bool
889gimple_assign_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
890{
891 enum tree_code code = gimple_assign_rhs_code (stmt);
892 switch (get_gimple_rhs_class (code))
893 {
894 case GIMPLE_UNARY_RHS:
895 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
896 gimple_expr_type (stmt),
897 gimple_assign_rhs1 (stmt),
898 strict_overflow_p);
899 case GIMPLE_BINARY_RHS:
900 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
901 gimple_expr_type (stmt),
902 gimple_assign_rhs1 (stmt),
903 gimple_assign_rhs2 (stmt),
904 strict_overflow_p);
905 case GIMPLE_TERNARY_RHS:
906 return false;
907 case GIMPLE_SINGLE_RHS:
908 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt),
909 strict_overflow_p);
910 case GIMPLE_INVALID_RHS:
911 gcc_unreachable ();
912 default:
913 gcc_unreachable ();
914 }
915}
916
917/* Return true if return value of call STMT is know to be non-negative.
918 If the return value is based on the assumption that signed overflow is
919 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
920 *STRICT_OVERFLOW_P.*/
921
922static bool
923gimple_call_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
924{
925 tree arg0 = gimple_call_num_args (stmt) > 0 ?
926 gimple_call_arg (stmt, 0) : NULL_TREE;
927 tree arg1 = gimple_call_num_args (stmt) > 1 ?
928 gimple_call_arg (stmt, 1) : NULL_TREE;
929
930 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt),
931 gimple_call_fndecl (stmt),
932 arg0,
933 arg1,
934 strict_overflow_p);
935}
936
937/* Return true if STMT is know to to compute a non-negative value.
938 If the return value is based on the assumption that signed overflow is
939 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
940 *STRICT_OVERFLOW_P.*/
941
942static bool
943gimple_stmt_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
944{
945 switch (gimple_code (stmt))
946 {
947 case GIMPLE_ASSIGN:
948 return gimple_assign_nonnegative_warnv_p (stmt, strict_overflow_p);
949 case GIMPLE_CALL:
950 return gimple_call_nonnegative_warnv_p (stmt, strict_overflow_p);
951 default:
952 gcc_unreachable ();
953 }
954}
955
956/* Return true if the result of assignment STMT is know to be non-zero.
957 If the return value is based on the assumption that signed overflow is
958 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
959 *STRICT_OVERFLOW_P.*/
960
961static bool
962gimple_assign_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
963{
964 enum tree_code code = gimple_assign_rhs_code (stmt);
965 switch (get_gimple_rhs_class (code))
966 {
967 case GIMPLE_UNARY_RHS:
968 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
969 gimple_expr_type (stmt),
970 gimple_assign_rhs1 (stmt),
971 strict_overflow_p);
972 case GIMPLE_BINARY_RHS:
973 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
974 gimple_expr_type (stmt),
975 gimple_assign_rhs1 (stmt),
976 gimple_assign_rhs2 (stmt),
977 strict_overflow_p);
978 case GIMPLE_TERNARY_RHS:
979 return false;
980 case GIMPLE_SINGLE_RHS:
981 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt),
982 strict_overflow_p);
983 case GIMPLE_INVALID_RHS:
984 gcc_unreachable ();
985 default:
986 gcc_unreachable ();
987 }
988}
989
990/* Return true if STMT is know to to compute a non-zero value.
991 If the return value is based on the assumption that signed overflow is
992 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
993 *STRICT_OVERFLOW_P.*/
994
995static bool
996gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
997{
998 switch (gimple_code (stmt))
999 {
1000 case GIMPLE_ASSIGN:
1001 return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p);
1002 case GIMPLE_CALL:
1003 return gimple_alloca_call_p (stmt);
1004 default:
1005 gcc_unreachable ();
1006 }
1007}
1008
1009/* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
1010 obtained so far. */
1011
1012static bool
1013vrp_stmt_computes_nonzero (gimple stmt, bool *strict_overflow_p)
1014{
1015 if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p))
1016 return true;
1017
1018 /* If we have an expression of the form &X->a, then the expression
1019 is nonnull if X is nonnull. */
1020 if (is_gimple_assign (stmt)
1021 && gimple_assign_rhs_code (stmt) == ADDR_EXPR)
1022 {
1023 tree expr = gimple_assign_rhs1 (stmt);
1024 tree base = get_base_address (TREE_OPERAND (expr, 0));
1025
1026 if (base != NULL_TREE
1027 && TREE_CODE (base) == MEM_REF
1028 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1029 {
1030 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
1031 if (range_is_nonnull (vr))
1032 return true;
1033 }
1034 }
1035
1036 return false;
1037}
1038
1039/* Returns true if EXPR is a valid value (as expected by compare_values) --
1040 a gimple invariant, or SSA_NAME +- CST. */
1041
1042static bool
1043valid_value_p (tree expr)
1044{
1045 if (TREE_CODE (expr) == SSA_NAME)
1046 return true;
1047
1048 if (TREE_CODE (expr) == PLUS_EXPR
1049 || TREE_CODE (expr) == MINUS_EXPR)
1050 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
1051 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
1052
1053 return is_gimple_min_invariant (expr);
1054}
1055
1056/* Return
1057 1 if VAL < VAL2
1058 0 if !(VAL < VAL2)
1059 -2 if those are incomparable. */
1060static inline int
1061operand_less_p (tree val, tree val2)
1062{
1063 /* LT is folded faster than GE and others. Inline the common case. */
1064 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
1065 {
1066 if (TYPE_UNSIGNED (TREE_TYPE (val)))
1067 return INT_CST_LT_UNSIGNED (val, val2);
1068 else
1069 {
1070 if (INT_CST_LT (val, val2))
1071 return 1;
1072 }
1073 }
1074 else
1075 {
1076 tree tcmp;
1077
1078 fold_defer_overflow_warnings ();
1079
1080 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
1081
1082 fold_undefer_and_ignore_overflow_warnings ();
1083
1084 if (!tcmp
1085 || TREE_CODE (tcmp) != INTEGER_CST)
1086 return -2;
1087
1088 if (!integer_zerop (tcmp))
1089 return 1;
1090 }
1091
1092 /* val >= val2, not considering overflow infinity. */
1093 if (is_negative_overflow_infinity (val))
1094 return is_negative_overflow_infinity (val2) ? 0 : 1;
1095 else if (is_positive_overflow_infinity (val2))
1096 return is_positive_overflow_infinity (val) ? 0 : 1;
1097
1098 return 0;
1099}
1100
1101/* Compare two values VAL1 and VAL2. Return
1102
1103 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1104 -1 if VAL1 < VAL2,
1105 0 if VAL1 == VAL2,
1106 +1 if VAL1 > VAL2, and
1107 +2 if VAL1 != VAL2
1108
1109 This is similar to tree_int_cst_compare but supports pointer values
1110 and values that cannot be compared at compile time.
1111
1112 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1113 true if the return value is only valid if we assume that signed
1114 overflow is undefined. */
1115
1116static int
1117compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
1118{
1119 if (val1 == val2)
1120 return 0;
1121
1122 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1123 both integers. */
1124 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
1125 == POINTER_TYPE_P (TREE_TYPE (val2)));
1126 /* Convert the two values into the same type. This is needed because
1127 sizetype causes sign extension even for unsigned types. */
1128 val2 = fold_convert (TREE_TYPE (val1), val2);
1129 STRIP_USELESS_TYPE_CONVERSION (val2);
1130
1131 if ((TREE_CODE (val1) == SSA_NAME
1132 || TREE_CODE (val1) == PLUS_EXPR
1133 || TREE_CODE (val1) == MINUS_EXPR)
1134 && (TREE_CODE (val2) == SSA_NAME
1135 || TREE_CODE (val2) == PLUS_EXPR
1136 || TREE_CODE (val2) == MINUS_EXPR))
1137 {
1138 tree n1, c1, n2, c2;
1139 enum tree_code code1, code2;
1140
1141 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1142 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1143 same name, return -2. */
1144 if (TREE_CODE (val1) == SSA_NAME)
1145 {
1146 code1 = SSA_NAME;
1147 n1 = val1;
1148 c1 = NULL_TREE;
1149 }
1150 else
1151 {
1152 code1 = TREE_CODE (val1);
1153 n1 = TREE_OPERAND (val1, 0);
1154 c1 = TREE_OPERAND (val1, 1);
1155 if (tree_int_cst_sgn (c1) == -1)
1156 {
1157 if (is_negative_overflow_infinity (c1))
1158 return -2;
1159 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
1160 if (!c1)
1161 return -2;
1162 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1163 }
1164 }
1165
1166 if (TREE_CODE (val2) == SSA_NAME)
1167 {
1168 code2 = SSA_NAME;
1169 n2 = val2;
1170 c2 = NULL_TREE;
1171 }
1172 else
1173 {
1174 code2 = TREE_CODE (val2);
1175 n2 = TREE_OPERAND (val2, 0);
1176 c2 = TREE_OPERAND (val2, 1);
1177 if (tree_int_cst_sgn (c2) == -1)
1178 {
1179 if (is_negative_overflow_infinity (c2))
1180 return -2;
1181 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
1182 if (!c2)
1183 return -2;
1184 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1185 }
1186 }
1187
1188 /* Both values must use the same name. */
1189 if (n1 != n2)
1190 return -2;
1191
1192 if (code1 == SSA_NAME
1193 && code2 == SSA_NAME)
1194 /* NAME == NAME */
1195 return 0;
1196
1197 /* If overflow is defined we cannot simplify more. */
1198 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
1199 return -2;
1200
1201 if (strict_overflow_p != NULL
1202 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
1203 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
1204 *strict_overflow_p = true;
1205
1206 if (code1 == SSA_NAME)
1207 {
1208 if (code2 == PLUS_EXPR)
1209 /* NAME < NAME + CST */
1210 return -1;
1211 else if (code2 == MINUS_EXPR)
1212 /* NAME > NAME - CST */
1213 return 1;
1214 }
1215 else if (code1 == PLUS_EXPR)
1216 {
1217 if (code2 == SSA_NAME)
1218 /* NAME + CST > NAME */
1219 return 1;
1220 else if (code2 == PLUS_EXPR)
1221 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1222 return compare_values_warnv (c1, c2, strict_overflow_p);
1223 else if (code2 == MINUS_EXPR)
1224 /* NAME + CST1 > NAME - CST2 */
1225 return 1;
1226 }
1227 else if (code1 == MINUS_EXPR)
1228 {
1229 if (code2 == SSA_NAME)
1230 /* NAME - CST < NAME */
1231 return -1;
1232 else if (code2 == PLUS_EXPR)
1233 /* NAME - CST1 < NAME + CST2 */
1234 return -1;
1235 else if (code2 == MINUS_EXPR)
1236 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1237 C1 and C2 are swapped in the call to compare_values. */
1238 return compare_values_warnv (c2, c1, strict_overflow_p);
1239 }
1240
1241 gcc_unreachable ();
1242 }
1243
1244 /* We cannot compare non-constants. */
1245 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
1246 return -2;
1247
1248 if (!POINTER_TYPE_P (TREE_TYPE (val1)))
1249 {
1250 /* We cannot compare overflowed values, except for overflow
1251 infinities. */
1252 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
1253 {
1254 if (strict_overflow_p != NULL)
1255 *strict_overflow_p = true;
1256 if (is_negative_overflow_infinity (val1))
1257 return is_negative_overflow_infinity (val2) ? 0 : -1;
1258 else if (is_negative_overflow_infinity (val2))
1259 return 1;
1260 else if (is_positive_overflow_infinity (val1))
1261 return is_positive_overflow_infinity (val2) ? 0 : 1;
1262 else if (is_positive_overflow_infinity (val2))
1263 return -1;
1264 return -2;
1265 }
1266
1267 return tree_int_cst_compare (val1, val2);
1268 }
1269 else
1270 {
1271 tree t;
1272
1273 /* First see if VAL1 and VAL2 are not the same. */
1274 if (val1 == val2 || operand_equal_p (val1, val2, 0))
1275 return 0;
1276
1277 /* If VAL1 is a lower address than VAL2, return -1. */
1278 if (operand_less_p (val1, val2) == 1)
1279 return -1;
1280
1281 /* If VAL1 is a higher address than VAL2, return +1. */
1282 if (operand_less_p (val2, val1) == 1)
1283 return 1;
1284
1285 /* If VAL1 is different than VAL2, return +2.
1286 For integer constants we either have already returned -1 or 1
1287 or they are equivalent. We still might succeed in proving
1288 something about non-trivial operands. */
1289 if (TREE_CODE (val1) != INTEGER_CST
1290 || TREE_CODE (val2) != INTEGER_CST)
1291 {
1292 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
1293 if (t && integer_onep (t))
1294 return 2;
1295 }
1296
1297 return -2;
1298 }
1299}
1300
1301/* Compare values like compare_values_warnv, but treat comparisons of
1302 nonconstants which rely on undefined overflow as incomparable. */
1303
1304static int
1305compare_values (tree val1, tree val2)
1306{
1307 bool sop;
1308 int ret;
1309
1310 sop = false;
1311 ret = compare_values_warnv (val1, val2, &sop);
1312 if (sop
1313 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
1314 ret = -2;
1315 return ret;
1316}
1317
1318
1319/* Return 1 if VAL is inside value range MIN <= VAL <= MAX,
1320 0 if VAL is not inside [MIN, MAX],
1321 -2 if we cannot tell either way.
1322
1323 Benchmark compile/20001226-1.c compilation time after changing this
1324 function. */
1325
1326static inline int
1327value_inside_range (tree val, tree min, tree max)
1328{
1329 int cmp1, cmp2;
1330
1331 cmp1 = operand_less_p (val, min);
1332 if (cmp1 == -2)
1333 return -2;
1334 if (cmp1 == 1)
1335 return 0;
1336
1337 cmp2 = operand_less_p (max, val);
1338 if (cmp2 == -2)
1339 return -2;
1340
1341 return !cmp2;
1342}
1343
1344
1345/* Return true if value ranges VR0 and VR1 have a non-empty
1346 intersection.
1347
1348 Benchmark compile/20001226-1.c compilation time after changing this
1349 function.
1350 */
1351
1352static inline bool
1353value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
1354{
1355 /* The value ranges do not intersect if the maximum of the first range is
1356 less than the minimum of the second range or vice versa.
1357 When those relations are unknown, we can't do any better. */
1358 if (operand_less_p (vr0->max, vr1->min) != 0)
1359 return false;
1360 if (operand_less_p (vr1->max, vr0->min) != 0)
1361 return false;
1362 return true;
1363}
1364
1365
1366/* Return 1 if [MIN, MAX] includes the value zero, 0 if it does not
1367 include the value zero, -2 if we cannot tell. */
1368
1369static inline int
1370range_includes_zero_p (tree min, tree max)
1371{
1372 tree zero = build_int_cst (TREE_TYPE (min), 0);
1373 return value_inside_range (zero, min, max);
1374}
1375
1376/* Return true if *VR is know to only contain nonnegative values. */
1377
1378static inline bool
1379value_range_nonnegative_p (value_range_t *vr)
1380{
1381 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1382 which would return a useful value should be encoded as a
1383 VR_RANGE. */
1384 if (vr->type == VR_RANGE)
1385 {
1386 int result = compare_values (vr->min, integer_zero_node);
1387 return (result == 0 || result == 1);
1388 }
1389
1390 return false;
1391}
1392
1393/* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1394 false otherwise or if no value range information is available. */
1395
1396bool
1397ssa_name_nonnegative_p (const_tree t)
1398{
1399 value_range_t *vr = get_value_range (t);
1400
1401 if (INTEGRAL_TYPE_P (t)
1402 && TYPE_UNSIGNED (t))
1403 return true;
1404
1405 if (!vr)
1406 return false;
1407
1408 return value_range_nonnegative_p (vr);
1409}
1410
1411/* If *VR has a value rante that is a single constant value return that,
1412 otherwise return NULL_TREE. */
1413
1414static tree
1415value_range_constant_singleton (value_range_t *vr)
1416{
1417 if (vr->type == VR_RANGE
1418 && operand_equal_p (vr->min, vr->max, 0)
1419 && is_gimple_min_invariant (vr->min))
1420 return vr->min;
1421
1422 return NULL_TREE;
1423}
1424
1425/* If OP has a value range with a single constant value return that,
1426 otherwise return NULL_TREE. This returns OP itself if OP is a
1427 constant. */
1428
1429static tree
1430op_with_constant_singleton_value_range (tree op)
1431{
1432 if (is_gimple_min_invariant (op))
1433 return op;
1434
1435 if (TREE_CODE (op) != SSA_NAME)
1436 return NULL_TREE;
1437
1438 return value_range_constant_singleton (get_value_range (op));
1439}
1440
1441/* Return true if op is in a boolean [0, 1] value-range. */
1442
1443static bool
1444op_with_boolean_value_range_p (tree op)
1445{
1446 value_range_t *vr;
1447
1448 if (TYPE_PRECISION (TREE_TYPE (op)) == 1)
1449 return true;
1450
1451 if (integer_zerop (op)
1452 || integer_onep (op))
1453 return true;
1454
1455 if (TREE_CODE (op) != SSA_NAME)
1456 return false;
1457
1458 vr = get_value_range (op);
1459 return (vr->type == VR_RANGE
1460 && integer_zerop (vr->min)
1461 && integer_onep (vr->max));
1462}
1463
1464/* Extract value range information from an ASSERT_EXPR EXPR and store
1465 it in *VR_P. */
1466
1467static void
1468extract_range_from_assert (value_range_t *vr_p, tree expr)
1469{
1470 tree var, cond, limit, min, max, type;
1471 value_range_t *var_vr, *limit_vr;
1472 enum tree_code cond_code;
1473
1474 var = ASSERT_EXPR_VAR (expr);
1475 cond = ASSERT_EXPR_COND (expr);
1476
1477 gcc_assert (COMPARISON_CLASS_P (cond));
1478
1479 /* Find VAR in the ASSERT_EXPR conditional. */
1480 if (var == TREE_OPERAND (cond, 0)
1481 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
1482 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
1483 {
1484 /* If the predicate is of the form VAR COMP LIMIT, then we just
1485 take LIMIT from the RHS and use the same comparison code. */
1486 cond_code = TREE_CODE (cond);
1487 limit = TREE_OPERAND (cond, 1);
1488 cond = TREE_OPERAND (cond, 0);
1489 }
1490 else
1491 {
1492 /* If the predicate is of the form LIMIT COMP VAR, then we need
1493 to flip around the comparison code to create the proper range
1494 for VAR. */
1495 cond_code = swap_tree_comparison (TREE_CODE (cond));
1496 limit = TREE_OPERAND (cond, 0);
1497 cond = TREE_OPERAND (cond, 1);
1498 }
1499
1500 limit = avoid_overflow_infinity (limit);
1501
1502 type = TREE_TYPE (var);
1503 gcc_assert (limit != var);
1504
1505 /* For pointer arithmetic, we only keep track of pointer equality
1506 and inequality. */
1507 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1508 {
1509 set_value_range_to_varying (vr_p);
1510 return;
1511 }
1512
1513 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1514 try to use LIMIT's range to avoid creating symbolic ranges
1515 unnecessarily. */
1516 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1517
1518 /* LIMIT's range is only interesting if it has any useful information. */
1519 if (limit_vr
1520 && (limit_vr->type == VR_UNDEFINED
1521 || limit_vr->type == VR_VARYING
1522 || symbolic_range_p (limit_vr)))
1523 limit_vr = NULL;
1524
1525 /* Initially, the new range has the same set of equivalences of
1526 VAR's range. This will be revised before returning the final
1527 value. Since assertions may be chained via mutually exclusive
1528 predicates, we will need to trim the set of equivalences before
1529 we are done. */
1530 gcc_assert (vr_p->equiv == NULL);
1531 add_equivalence (&vr_p->equiv, var);
1532
1533 /* Extract a new range based on the asserted comparison for VAR and
1534 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1535 will only use it for equality comparisons (EQ_EXPR). For any
1536 other kind of assertion, we cannot derive a range from LIMIT's
1537 anti-range that can be used to describe the new range. For
1538 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1539 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1540 no single range for x_2 that could describe LE_EXPR, so we might
1541 as well build the range [b_4, +INF] for it.
1542 One special case we handle is extracting a range from a
1543 range test encoded as (unsigned)var + CST <= limit. */
1544 if (TREE_CODE (cond) == NOP_EXPR
1545 || TREE_CODE (cond) == PLUS_EXPR)
1546 {
1547 if (TREE_CODE (cond) == PLUS_EXPR)
1548 {
1549 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)),
1550 TREE_OPERAND (cond, 1));
1551 max = int_const_binop (PLUS_EXPR, limit, min);
1552 cond = TREE_OPERAND (cond, 0);
1553 }
1554 else
1555 {
1556 min = build_int_cst (TREE_TYPE (var), 0);
1557 max = limit;
1558 }
1559
1560 /* Make sure to not set TREE_OVERFLOW on the final type
1561 conversion. We are willingly interpreting large positive
1562 unsigned values as negative singed values here. */
1563 min = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (min),
1564 0, false);
1565 max = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (max),
1566 0, false);
1567
1568 /* We can transform a max, min range to an anti-range or
1569 vice-versa. Use set_and_canonicalize_value_range which does
1570 this for us. */
1571 if (cond_code == LE_EXPR)
1572 set_and_canonicalize_value_range (vr_p, VR_RANGE,
1573 min, max, vr_p->equiv);
1574 else if (cond_code == GT_EXPR)
1575 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
1576 min, max, vr_p->equiv);
1577 else
1578 gcc_unreachable ();
1579 }
1580 else if (cond_code == EQ_EXPR)
1581 {
1582 enum value_range_type range_type;
1583
1584 if (limit_vr)
1585 {
1586 range_type = limit_vr->type;
1587 min = limit_vr->min;
1588 max = limit_vr->max;
1589 }
1590 else
1591 {
1592 range_type = VR_RANGE;
1593 min = limit;
1594 max = limit;
1595 }
1596
1597 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1598
1599 /* When asserting the equality VAR == LIMIT and LIMIT is another
1600 SSA name, the new range will also inherit the equivalence set
1601 from LIMIT. */
1602 if (TREE_CODE (limit) == SSA_NAME)
1603 add_equivalence (&vr_p->equiv, limit);
1604 }
1605 else if (cond_code == NE_EXPR)
1606 {
1607 /* As described above, when LIMIT's range is an anti-range and
1608 this assertion is an inequality (NE_EXPR), then we cannot
1609 derive anything from the anti-range. For instance, if
1610 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1611 not imply that VAR's range is [0, 0]. So, in the case of
1612 anti-ranges, we just assert the inequality using LIMIT and
1613 not its anti-range.
1614
1615 If LIMIT_VR is a range, we can only use it to build a new
1616 anti-range if LIMIT_VR is a single-valued range. For
1617 instance, if LIMIT_VR is [0, 1], the predicate
1618 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1619 Rather, it means that for value 0 VAR should be ~[0, 0]
1620 and for value 1, VAR should be ~[1, 1]. We cannot
1621 represent these ranges.
1622
1623 The only situation in which we can build a valid
1624 anti-range is when LIMIT_VR is a single-valued range
1625 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1626 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1627 if (limit_vr
1628 && limit_vr->type == VR_RANGE
1629 && compare_values (limit_vr->min, limit_vr->max) == 0)
1630 {
1631 min = limit_vr->min;
1632 max = limit_vr->max;
1633 }
1634 else
1635 {
1636 /* In any other case, we cannot use LIMIT's range to build a
1637 valid anti-range. */
1638 min = max = limit;
1639 }
1640
1641 /* If MIN and MAX cover the whole range for their type, then
1642 just use the original LIMIT. */
1643 if (INTEGRAL_TYPE_P (type)
1644 && vrp_val_is_min (min)
1645 && vrp_val_is_max (max))
1646 min = max = limit;
1647
1648 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1649 }
1650 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1651 {
1652 min = TYPE_MIN_VALUE (type);
1653
1654 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1655 max = limit;
1656 else
1657 {
1658 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1659 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1660 LT_EXPR. */
1661 max = limit_vr->max;
1662 }
1663
1664 /* If the maximum value forces us to be out of bounds, simply punt.
1665 It would be pointless to try and do anything more since this
1666 all should be optimized away above us. */
1667 if ((cond_code == LT_EXPR
1668 && compare_values (max, min) == 0)
1669 || (CONSTANT_CLASS_P (max) && TREE_OVERFLOW (max)))
1670 set_value_range_to_varying (vr_p);
1671 else
1672 {
1673 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1674 if (cond_code == LT_EXPR)
1675 {
1676 if (TYPE_PRECISION (TREE_TYPE (max)) == 1
1677 && !TYPE_UNSIGNED (TREE_TYPE (max)))
1678 max = fold_build2 (PLUS_EXPR, TREE_TYPE (max), max,
1679 build_int_cst (TREE_TYPE (max), -1));
1680 else
1681 max = fold_build2 (MINUS_EXPR, TREE_TYPE (max), max,
1682 build_int_cst (TREE_TYPE (max), 1));
1683 if (EXPR_P (max))
1684 TREE_NO_WARNING (max) = 1;
1685 }
1686
1687 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1688 }
1689 }
1690 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1691 {
1692 max = TYPE_MAX_VALUE (type);
1693
1694 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1695 min = limit;
1696 else
1697 {
1698 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1699 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1700 GT_EXPR. */
1701 min = limit_vr->min;
1702 }
1703
1704 /* If the minimum value forces us to be out of bounds, simply punt.
1705 It would be pointless to try and do anything more since this
1706 all should be optimized away above us. */
1707 if ((cond_code == GT_EXPR
1708 && compare_values (min, max) == 0)
1709 || (CONSTANT_CLASS_P (min) && TREE_OVERFLOW (min)))
1710 set_value_range_to_varying (vr_p);
1711 else
1712 {
1713 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1714 if (cond_code == GT_EXPR)
1715 {
1716 if (TYPE_PRECISION (TREE_TYPE (min)) == 1
1717 && !TYPE_UNSIGNED (TREE_TYPE (min)))
1718 min = fold_build2 (MINUS_EXPR, TREE_TYPE (min), min,
1719 build_int_cst (TREE_TYPE (min), -1));
1720 else
1721 min = fold_build2 (PLUS_EXPR, TREE_TYPE (min), min,
1722 build_int_cst (TREE_TYPE (min), 1));
1723 if (EXPR_P (min))
1724 TREE_NO_WARNING (min) = 1;
1725 }
1726
1727 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1728 }
1729 }
1730 else
1731 gcc_unreachable ();
1732
1733 /* If VAR already had a known range, it may happen that the new
1734 range we have computed and VAR's range are not compatible. For
1735 instance,
1736
1737 if (p_5 == NULL)
1738 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1739 x_7 = p_6->fld;
1740 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1741
1742 While the above comes from a faulty program, it will cause an ICE
1743 later because p_8 and p_6 will have incompatible ranges and at
1744 the same time will be considered equivalent. A similar situation
1745 would arise from
1746
1747 if (i_5 > 10)
1748 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1749 if (i_5 < 5)
1750 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1751
1752 Again i_6 and i_7 will have incompatible ranges. It would be
1753 pointless to try and do anything with i_7's range because
1754 anything dominated by 'if (i_5 < 5)' will be optimized away.
1755 Note, due to the wa in which simulation proceeds, the statement
1756 i_7 = ASSERT_EXPR <...> we would never be visited because the
1757 conditional 'if (i_5 < 5)' always evaluates to false. However,
1758 this extra check does not hurt and may protect against future
1759 changes to VRP that may get into a situation similar to the
1760 NULL pointer dereference example.
1761
1762 Note that these compatibility tests are only needed when dealing
1763 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1764 are both anti-ranges, they will always be compatible, because two
1765 anti-ranges will always have a non-empty intersection. */
1766
1767 var_vr = get_value_range (var);
1768
1769 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1770 ranges or anti-ranges. */
1771 if (vr_p->type == VR_VARYING
1772 || vr_p->type == VR_UNDEFINED
1773 || var_vr->type == VR_VARYING
1774 || var_vr->type == VR_UNDEFINED
1775 || symbolic_range_p (vr_p)
1776 || symbolic_range_p (var_vr))
1777 return;
1778
1779 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
1780 {
1781 /* If the two ranges have a non-empty intersection, we can
1782 refine the resulting range. Since the assert expression
1783 creates an equivalency and at the same time it asserts a
1784 predicate, we can take the intersection of the two ranges to
1785 get better precision. */
1786 if (value_ranges_intersect_p (var_vr, vr_p))
1787 {
1788 /* Use the larger of the two minimums. */
1789 if (compare_values (vr_p->min, var_vr->min) == -1)
1790 min = var_vr->min;
1791 else
1792 min = vr_p->min;
1793
1794 /* Use the smaller of the two maximums. */
1795 if (compare_values (vr_p->max, var_vr->max) == 1)
1796 max = var_vr->max;
1797 else
1798 max = vr_p->max;
1799
1800 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
1801 }
1802 else
1803 {
1804 /* The two ranges do not intersect, set the new range to
1805 VARYING, because we will not be able to do anything
1806 meaningful with it. */
1807 set_value_range_to_varying (vr_p);
1808 }
1809 }
1810 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE)
1811 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE))
1812 {
1813 /* A range and an anti-range will cancel each other only if
1814 their ends are the same. For instance, in the example above,
1815 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1816 so VR_P should be set to VR_VARYING. */
1817 if (compare_values (var_vr->min, vr_p->min) == 0
1818 && compare_values (var_vr->max, vr_p->max) == 0)
1819 set_value_range_to_varying (vr_p);
1820 else
1821 {
1822 tree min, max, anti_min, anti_max, real_min, real_max;
1823 int cmp;
1824
1825 /* We want to compute the logical AND of the two ranges;
1826 there are three cases to consider.
1827
1828
1829 1. The VR_ANTI_RANGE range is completely within the
1830 VR_RANGE and the endpoints of the ranges are
1831 different. In that case the resulting range
1832 should be whichever range is more precise.
1833 Typically that will be the VR_RANGE.
1834
1835 2. The VR_ANTI_RANGE is completely disjoint from
1836 the VR_RANGE. In this case the resulting range
1837 should be the VR_RANGE.
1838
1839 3. There is some overlap between the VR_ANTI_RANGE
1840 and the VR_RANGE.
1841
1842 3a. If the high limit of the VR_ANTI_RANGE resides
1843 within the VR_RANGE, then the result is a new
1844 VR_RANGE starting at the high limit of the
1845 VR_ANTI_RANGE + 1 and extending to the
1846 high limit of the original VR_RANGE.
1847
1848 3b. If the low limit of the VR_ANTI_RANGE resides
1849 within the VR_RANGE, then the result is a new
1850 VR_RANGE starting at the low limit of the original
1851 VR_RANGE and extending to the low limit of the
1852 VR_ANTI_RANGE - 1. */
1853 if (vr_p->type == VR_ANTI_RANGE)
1854 {
1855 anti_min = vr_p->min;
1856 anti_max = vr_p->max;
1857 real_min = var_vr->min;
1858 real_max = var_vr->max;
1859 }
1860 else
1861 {
1862 anti_min = var_vr->min;
1863 anti_max = var_vr->max;
1864 real_min = vr_p->min;
1865 real_max = vr_p->max;
1866 }
1867
1868
1869 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1870 not including any endpoints. */
1871 if (compare_values (anti_max, real_max) == -1
1872 && compare_values (anti_min, real_min) == 1)
1873 {
1874 /* If the range is covering the whole valid range of
1875 the type keep the anti-range. */
1876 if (!vrp_val_is_min (real_min)
1877 || !vrp_val_is_max (real_max))
1878 set_value_range (vr_p, VR_RANGE, real_min,
1879 real_max, vr_p->equiv);
1880 }
1881 /* Case 2, VR_ANTI_RANGE completely disjoint from
1882 VR_RANGE. */
1883 else if (compare_values (anti_min, real_max) == 1
1884 || compare_values (anti_max, real_min) == -1)
1885 {
1886 set_value_range (vr_p, VR_RANGE, real_min,
1887 real_max, vr_p->equiv);
1888 }
1889 /* Case 3a, the anti-range extends into the low
1890 part of the real range. Thus creating a new
1891 low for the real range. */
1892 else if (((cmp = compare_values (anti_max, real_min)) == 1
1893 || cmp == 0)
1894 && compare_values (anti_max, real_max) == -1)
1895 {
1896 gcc_assert (!is_positive_overflow_infinity (anti_max));
1897 if (needs_overflow_infinity (TREE_TYPE (anti_max))
1898 && vrp_val_is_max (anti_max))
1899 {
1900 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1901 {
1902 set_value_range_to_varying (vr_p);
1903 return;
1904 }
1905 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1906 }
1907 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1908 {
1909 if (TYPE_PRECISION (TREE_TYPE (var_vr->min)) == 1
1910 && !TYPE_UNSIGNED (TREE_TYPE (var_vr->min)))
1911 min = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1912 anti_max,
1913 build_int_cst (TREE_TYPE (var_vr->min),
1914 -1));
1915 else
1916 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1917 anti_max,
1918 build_int_cst (TREE_TYPE (var_vr->min),
1919 1));
1920 }
1921 else
1922 min = fold_build_pointer_plus_hwi (anti_max, 1);
1923 max = real_max;
1924 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1925 }
1926 /* Case 3b, the anti-range extends into the high
1927 part of the real range. Thus creating a new
1928 higher for the real range. */
1929 else if (compare_values (anti_min, real_min) == 1
1930 && ((cmp = compare_values (anti_min, real_max)) == -1
1931 || cmp == 0))
1932 {
1933 gcc_assert (!is_negative_overflow_infinity (anti_min));
1934 if (needs_overflow_infinity (TREE_TYPE (anti_min))
1935 && vrp_val_is_min (anti_min))
1936 {
1937 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1938 {
1939 set_value_range_to_varying (vr_p);
1940 return;
1941 }
1942 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1943 }
1944 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1945 {
1946 if (TYPE_PRECISION (TREE_TYPE (var_vr->min)) == 1
1947 && !TYPE_UNSIGNED (TREE_TYPE (var_vr->min)))
1948 max = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1949 anti_min,
1950 build_int_cst (TREE_TYPE (var_vr->min),
1951 -1));
1952 else
1953 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1954 anti_min,
1955 build_int_cst (TREE_TYPE (var_vr->min),
1956 1));
1957 }
1958 else
1959 max = fold_build_pointer_plus_hwi (anti_min, -1);
1960 min = real_min;
1961 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1962 }
1963 }
1964 }
1965}
1966
1967
1968/* Extract range information from SSA name VAR and store it in VR. If
1969 VAR has an interesting range, use it. Otherwise, create the
1970 range [VAR, VAR] and return it. This is useful in situations where
1971 we may have conditionals testing values of VARYING names. For
1972 instance,
1973
1974 x_3 = y_5;
1975 if (x_3 > y_5)
1976 ...
1977
1978 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1979 always false. */
1980
1981static void
1982extract_range_from_ssa_name (value_range_t *vr, tree var)
1983{
1984 value_range_t *var_vr = get_value_range (var);
1985
1986 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
1987 copy_value_range (vr, var_vr);
1988 else
1989 set_value_range (vr, VR_RANGE, var, var, NULL);
1990
1991 add_equivalence (&vr->equiv, var);
1992}
1993
1994
1995/* Wrapper around int_const_binop. If the operation overflows and we
1996 are not using wrapping arithmetic, then adjust the result to be
1997 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1998 NULL_TREE if we need to use an overflow infinity representation but
1999 the type does not support it. */
2000
2001static tree
2002vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
2003{
2004 tree res;
2005
2006 res = int_const_binop (code, val1, val2);
2007
2008 /* If we are using unsigned arithmetic, operate symbolically
2009 on -INF and +INF as int_const_binop only handles signed overflow. */
2010 if (TYPE_UNSIGNED (TREE_TYPE (val1)))
2011 {
2012 int checkz = compare_values (res, val1);
2013 bool overflow = false;
2014
2015 /* Ensure that res = val1 [+*] val2 >= val1
2016 or that res = val1 - val2 <= val1. */
2017 if ((code == PLUS_EXPR
2018 && !(checkz == 1 || checkz == 0))
2019 || (code == MINUS_EXPR
2020 && !(checkz == 0 || checkz == -1)))
2021 {
2022 overflow = true;
2023 }
2024 /* Checking for multiplication overflow is done by dividing the
2025 output of the multiplication by the first input of the
2026 multiplication. If the result of that division operation is
2027 not equal to the second input of the multiplication, then the
2028 multiplication overflowed. */
2029 else if (code == MULT_EXPR && !integer_zerop (val1))
2030 {
2031 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
2032 res,
2033 val1);
2034 int check = compare_values (tmp, val2);
2035
2036 if (check != 0)
2037 overflow = true;
2038 }
2039
2040 if (overflow)
2041 {
2042 res = copy_node (res);
2043 TREE_OVERFLOW (res) = 1;
2044 }
2045
2046 }
2047 else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
2048 /* If the singed operation wraps then int_const_binop has done
2049 everything we want. */
2050 ;
2051 else if ((TREE_OVERFLOW (res)
2052 && !TREE_OVERFLOW (val1)
2053 && !TREE_OVERFLOW (val2))
2054 || is_overflow_infinity (val1)
2055 || is_overflow_infinity (val2))
2056 {
2057 /* If the operation overflowed but neither VAL1 nor VAL2 are
2058 overflown, return -INF or +INF depending on the operation
2059 and the combination of signs of the operands. */
2060 int sgn1 = tree_int_cst_sgn (val1);
2061 int sgn2 = tree_int_cst_sgn (val2);
2062
2063 if (needs_overflow_infinity (TREE_TYPE (res))
2064 && !supports_overflow_infinity (TREE_TYPE (res)))
2065 return NULL_TREE;
2066
2067 /* We have to punt on adding infinities of different signs,
2068 since we can't tell what the sign of the result should be.
2069 Likewise for subtracting infinities of the same sign. */
2070 if (((code == PLUS_EXPR && sgn1 != sgn2)
2071 || (code == MINUS_EXPR && sgn1 == sgn2))
2072 && is_overflow_infinity (val1)
2073 && is_overflow_infinity (val2))
2074 return NULL_TREE;
2075
2076 /* Don't try to handle division or shifting of infinities. */
2077 if ((code == TRUNC_DIV_EXPR
2078 || code == FLOOR_DIV_EXPR
2079 || code == CEIL_DIV_EXPR
2080 || code == EXACT_DIV_EXPR
2081 || code == ROUND_DIV_EXPR
2082 || code == RSHIFT_EXPR)
2083 && (is_overflow_infinity (val1)
2084 || is_overflow_infinity (val2)))
2085 return NULL_TREE;
2086
2087 /* Notice that we only need to handle the restricted set of
2088 operations handled by extract_range_from_binary_expr.
2089 Among them, only multiplication, addition and subtraction
2090 can yield overflow without overflown operands because we
2091 are working with integral types only... except in the
2092 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
2093 for division too. */
2094
2095 /* For multiplication, the sign of the overflow is given
2096 by the comparison of the signs of the operands. */
2097 if ((code == MULT_EXPR && sgn1 == sgn2)
2098 /* For addition, the operands must be of the same sign
2099 to yield an overflow. Its sign is therefore that
2100 of one of the operands, for example the first. For
2101 infinite operands X + -INF is negative, not positive. */
2102 || (code == PLUS_EXPR
2103 && (sgn1 >= 0
2104 ? !is_negative_overflow_infinity (val2)
2105 : is_positive_overflow_infinity (val2)))
2106 /* For subtraction, non-infinite operands must be of
2107 different signs to yield an overflow. Its sign is
2108 therefore that of the first operand or the opposite of
2109 that of the second operand. A first operand of 0 counts
2110 as positive here, for the corner case 0 - (-INF), which
2111 overflows, but must yield +INF. For infinite operands 0
2112 - INF is negative, not positive. */
2113 || (code == MINUS_EXPR
2114 && (sgn1 >= 0
2115 ? !is_positive_overflow_infinity (val2)
2116 : is_negative_overflow_infinity (val2)))
2117 /* We only get in here with positive shift count, so the
2118 overflow direction is the same as the sign of val1.
2119 Actually rshift does not overflow at all, but we only
2120 handle the case of shifting overflowed -INF and +INF. */
2121 || (code == RSHIFT_EXPR
2122 && sgn1 >= 0)
2123 /* For division, the only case is -INF / -1 = +INF. */
2124 || code == TRUNC_DIV_EXPR
2125 || code == FLOOR_DIV_EXPR
2126 || code == CEIL_DIV_EXPR
2127 || code == EXACT_DIV_EXPR
2128 || code == ROUND_DIV_EXPR)
2129 return (needs_overflow_infinity (TREE_TYPE (res))
2130 ? positive_overflow_infinity (TREE_TYPE (res))
2131 : TYPE_MAX_VALUE (TREE_TYPE (res)));
2132 else
2133 return (needs_overflow_infinity (TREE_TYPE (res))
2134 ? negative_overflow_infinity (TREE_TYPE (res))
2135 : TYPE_MIN_VALUE (TREE_TYPE (res)));
2136 }
2137
2138 return res;
2139}
2140
2141
2142/* For range VR compute two double_int bitmasks. In *MAY_BE_NONZERO
2143 bitmask if some bit is unset, it means for all numbers in the range
2144 the bit is 0, otherwise it might be 0 or 1. In *MUST_BE_NONZERO
2145 bitmask if some bit is set, it means for all numbers in the range
2146 the bit is 1, otherwise it might be 0 or 1. */
2147
2148static bool
2149zero_nonzero_bits_from_vr (value_range_t *vr,
2150 double_int *may_be_nonzero,
2151 double_int *must_be_nonzero)
2152{
2153 *may_be_nonzero = double_int_minus_one;
2154 *must_be_nonzero = double_int_zero;
2155 if (!range_int_cst_p (vr))
2156 return false;
2157
2158 if (range_int_cst_singleton_p (vr))
2159 {
2160 *may_be_nonzero = tree_to_double_int (vr->min);
2161 *must_be_nonzero = *may_be_nonzero;
2162 }
2163 else if (tree_int_cst_sgn (vr->min) >= 0
2164 || tree_int_cst_sgn (vr->max) < 0)
2165 {
2166 double_int dmin = tree_to_double_int (vr->min);
2167 double_int dmax = tree_to_double_int (vr->max);
2168 double_int xor_mask = double_int_xor (dmin, dmax);
2169 *may_be_nonzero = double_int_ior (dmin, dmax);
2170 *must_be_nonzero = double_int_and (dmin, dmax);
2171 if (xor_mask.high != 0)
2172 {
2173 unsigned HOST_WIDE_INT mask
2174 = ((unsigned HOST_WIDE_INT) 1
2175 << floor_log2 (xor_mask.high)) - 1;
2176 may_be_nonzero->low = ALL_ONES;
2177 may_be_nonzero->high |= mask;
2178 must_be_nonzero->low = 0;
2179 must_be_nonzero->high &= ~mask;
2180 }
2181 else if (xor_mask.low != 0)
2182 {
2183 unsigned HOST_WIDE_INT mask
2184 = ((unsigned HOST_WIDE_INT) 1
2185 << floor_log2 (xor_mask.low)) - 1;
2186 may_be_nonzero->low |= mask;
2187 must_be_nonzero->low &= ~mask;
2188 }
2189 }
2190
2191 return true;
2192}
2193
2194/* Helper to extract a value-range *VR for a multiplicative operation
2195 *VR0 CODE *VR1. */
2196
2197static void
2198extract_range_from_multiplicative_op_1 (value_range_t *vr,
2199 enum tree_code code,
2200 value_range_t *vr0, value_range_t *vr1)
2201{
2202 enum value_range_type type;
2203 tree val[4];
2204 size_t i;
2205 tree min, max;
2206 bool sop;
2207 int cmp;
2208
2209 /* Multiplications, divisions and shifts are a bit tricky to handle,
2210 depending on the mix of signs we have in the two ranges, we
2211 need to operate on different values to get the minimum and
2212 maximum values for the new range. One approach is to figure
2213 out all the variations of range combinations and do the
2214 operations.
2215
2216 However, this involves several calls to compare_values and it
2217 is pretty convoluted. It's simpler to do the 4 operations
2218 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2219 MAX1) and then figure the smallest and largest values to form
2220 the new range. */
2221 gcc_assert (code == MULT_EXPR
2222 || code == TRUNC_DIV_EXPR
2223 || code == FLOOR_DIV_EXPR
2224 || code == CEIL_DIV_EXPR
2225 || code == EXACT_DIV_EXPR
2226 || code == ROUND_DIV_EXPR
2227 || code == RSHIFT_EXPR);
2228 gcc_assert ((vr0->type == VR_RANGE
2229 || (code == MULT_EXPR && vr0->type == VR_ANTI_RANGE))
2230 && vr0->type == vr1->type);
2231
2232 type = vr0->type;
2233
2234 /* Compute the 4 cross operations. */
2235 sop = false;
2236 val[0] = vrp_int_const_binop (code, vr0->min, vr1->min);
2237 if (val[0] == NULL_TREE)
2238 sop = true;
2239
2240 if (vr1->max == vr1->min)
2241 val[1] = NULL_TREE;
2242 else
2243 {
2244 val[1] = vrp_int_const_binop (code, vr0->min, vr1->max);
2245 if (val[1] == NULL_TREE)
2246 sop = true;
2247 }
2248
2249 if (vr0->max == vr0->min)
2250 val[2] = NULL_TREE;
2251 else
2252 {
2253 val[2] = vrp_int_const_binop (code, vr0->max, vr1->min);
2254 if (val[2] == NULL_TREE)
2255 sop = true;
2256 }
2257
2258 if (vr0->min == vr0->max || vr1->min == vr1->max)
2259 val[3] = NULL_TREE;
2260 else
2261 {
2262 val[3] = vrp_int_const_binop (code, vr0->max, vr1->max);
2263 if (val[3] == NULL_TREE)
2264 sop = true;
2265 }
2266
2267 if (sop)
2268 {
2269 set_value_range_to_varying (vr);
2270 return;
2271 }
2272
2273 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2274 of VAL[i]. */
2275 min = val[0];
2276 max = val[0];
2277 for (i = 1; i < 4; i++)
2278 {
2279 if (!is_gimple_min_invariant (min)
2280 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2281 || !is_gimple_min_invariant (max)
2282 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2283 break;
2284
2285 if (val[i])
2286 {
2287 if (!is_gimple_min_invariant (val[i])
2288 || (TREE_OVERFLOW (val[i])
2289 && !is_overflow_infinity (val[i])))
2290 {
2291 /* If we found an overflowed value, set MIN and MAX
2292 to it so that we set the resulting range to
2293 VARYING. */
2294 min = max = val[i];
2295 break;
2296 }
2297
2298 if (compare_values (val[i], min) == -1)
2299 min = val[i];
2300
2301 if (compare_values (val[i], max) == 1)
2302 max = val[i];
2303 }
2304 }
2305
2306 /* If either MIN or MAX overflowed, then set the resulting range to
2307 VARYING. But we do accept an overflow infinity
2308 representation. */
2309 if (min == NULL_TREE
2310 || !is_gimple_min_invariant (min)
2311 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2312 || max == NULL_TREE
2313 || !is_gimple_min_invariant (max)
2314 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2315 {
2316 set_value_range_to_varying (vr);
2317 return;
2318 }
2319
2320 /* We punt if:
2321 1) [-INF, +INF]
2322 2) [-INF, +-INF(OVF)]
2323 3) [+-INF(OVF), +INF]
2324 4) [+-INF(OVF), +-INF(OVF)]
2325 We learn nothing when we have INF and INF(OVF) on both sides.
2326 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2327 overflow. */
2328 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2329 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2330 {
2331 set_value_range_to_varying (vr);
2332 return;
2333 }
2334
2335 cmp = compare_values (min, max);
2336 if (cmp == -2 || cmp == 1)
2337 {
2338 /* If the new range has its limits swapped around (MIN > MAX),
2339 then the operation caused one of them to wrap around, mark
2340 the new range VARYING. */
2341 set_value_range_to_varying (vr);
2342 }
2343 else
2344 set_value_range (vr, type, min, max, NULL);
2345}
2346
2347/* Extract range information from a binary operation CODE based on
2348 the ranges of each of its operands, *VR0 and *VR1 with resulting
2349 type EXPR_TYPE. The resulting range is stored in *VR. */
2350
2351static void
2352extract_range_from_binary_expr_1 (value_range_t *vr,
2353 enum tree_code code, tree expr_type,
2354 value_range_t *vr0_, value_range_t *vr1_)
2355{
2356 value_range_t vr0 = *vr0_, vr1 = *vr1_;
2357 enum value_range_type type;
2358 tree min = NULL_TREE, max = NULL_TREE;
2359 int cmp;
2360
2361 if (!INTEGRAL_TYPE_P (expr_type)
2362 && !POINTER_TYPE_P (expr_type))
2363 {
2364 set_value_range_to_varying (vr);
2365 return;
2366 }
2367
2368 /* Not all binary expressions can be applied to ranges in a
2369 meaningful way. Handle only arithmetic operations. */
2370 if (code != PLUS_EXPR
2371 && code != MINUS_EXPR
2372 && code != POINTER_PLUS_EXPR
2373 && code != MULT_EXPR
2374 && code != TRUNC_DIV_EXPR
2375 && code != FLOOR_DIV_EXPR
2376 && code != CEIL_DIV_EXPR
2377 && code != EXACT_DIV_EXPR
2378 && code != ROUND_DIV_EXPR
2379 && code != TRUNC_MOD_EXPR
2380 && code != RSHIFT_EXPR
2381 && code != MIN_EXPR
2382 && code != MAX_EXPR
2383 && code != BIT_AND_EXPR
2384 && code != BIT_IOR_EXPR
2385 && code != BIT_XOR_EXPR)
2386 {
2387 set_value_range_to_varying (vr);
2388 return;
2389 }
2390
2391 /* If both ranges are UNDEFINED, so is the result. */
2392 if (vr0.type == VR_UNDEFINED && vr1.type == VR_UNDEFINED)
2393 {
2394 set_value_range_to_undefined (vr);
2395 return;
2396 }
2397 /* If one of the ranges is UNDEFINED drop it to VARYING for the following
2398 code. At some point we may want to special-case operations that
2399 have UNDEFINED result for all or some value-ranges of the not UNDEFINED
2400 operand. */
2401 else if (vr0.type == VR_UNDEFINED)
2402 set_value_range_to_varying (&vr0);
2403 else if (vr1.type == VR_UNDEFINED)
2404 set_value_range_to_varying (&vr1);
2405
2406 /* The type of the resulting value range defaults to VR0.TYPE. */
2407 type = vr0.type;
2408
2409 /* Refuse to operate on VARYING ranges, ranges of different kinds
2410 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2411 because we may be able to derive a useful range even if one of
2412 the operands is VR_VARYING or symbolic range. Similarly for
2413 divisions. TODO, we may be able to derive anti-ranges in
2414 some cases. */
2415 if (code != BIT_AND_EXPR
2416 && code != BIT_IOR_EXPR
2417 && code != TRUNC_DIV_EXPR
2418 && code != FLOOR_DIV_EXPR
2419 && code != CEIL_DIV_EXPR
2420 && code != EXACT_DIV_EXPR
2421 && code != ROUND_DIV_EXPR
2422 && code != TRUNC_MOD_EXPR
2423 && (vr0.type == VR_VARYING
2424 || vr1.type == VR_VARYING
2425 || vr0.type != vr1.type
2426 || symbolic_range_p (&vr0)
2427 || symbolic_range_p (&vr1)))
2428 {
2429 set_value_range_to_varying (vr);
2430 return;
2431 }
2432
2433 /* Now evaluate the expression to determine the new range. */
2434 if (POINTER_TYPE_P (expr_type))
2435 {
2436 if (code == MIN_EXPR || code == MAX_EXPR)
2437 {
2438 /* For MIN/MAX expressions with pointers, we only care about
2439 nullness, if both are non null, then the result is nonnull.
2440 If both are null, then the result is null. Otherwise they
2441 are varying. */
2442 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2443 set_value_range_to_nonnull (vr, expr_type);
2444 else if (range_is_null (&vr0) && range_is_null (&vr1))
2445 set_value_range_to_null (vr, expr_type);
2446 else
2447 set_value_range_to_varying (vr);
2448 }
2449 else if (code == POINTER_PLUS_EXPR)
2450 {
2451 /* For pointer types, we are really only interested in asserting
2452 whether the expression evaluates to non-NULL. */
2453 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
2454 set_value_range_to_nonnull (vr, expr_type);
2455 else if (range_is_null (&vr0) && range_is_null (&vr1))
2456 set_value_range_to_null (vr, expr_type);
2457 else
2458 set_value_range_to_varying (vr);
2459 }
2460 else if (code == BIT_AND_EXPR)
2461 {
2462 /* For pointer types, we are really only interested in asserting
2463 whether the expression evaluates to non-NULL. */
2464 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2465 set_value_range_to_nonnull (vr, expr_type);
2466 else if (range_is_null (&vr0) || range_is_null (&vr1))
2467 set_value_range_to_null (vr, expr_type);
2468 else
2469 set_value_range_to_varying (vr);
2470 }
2471 else
2472 set_value_range_to_varying (vr);
2473
2474 return;
2475 }
2476
2477 /* For integer ranges, apply the operation to each end of the
2478 range and see what we end up with. */
2479 if (code == PLUS_EXPR)
2480 {
2481 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2482 VR_VARYING. It would take more effort to compute a precise
2483 range for such a case. For example, if we have op0 == 1 and
2484 op1 == -1 with their ranges both being ~[0,0], we would have
2485 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2486 Note that we are guaranteed to have vr0.type == vr1.type at
2487 this point. */
2488 if (vr0.type == VR_ANTI_RANGE)
2489 {
2490 set_value_range_to_varying (vr);
2491 return;
2492 }
2493
2494 /* For operations that make the resulting range directly
2495 proportional to the original ranges, apply the operation to
2496 the same end of each range. */
2497 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2498 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2499
2500 /* If both additions overflowed the range kind is still correct.
2501 This happens regularly with subtracting something in unsigned
2502 arithmetic.
2503 ??? See PR30318 for all the cases we do not handle. */
2504 if ((TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2505 && (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2506 {
2507 min = build_int_cst_wide (TREE_TYPE (min),
2508 TREE_INT_CST_LOW (min),
2509 TREE_INT_CST_HIGH (min));
2510 max = build_int_cst_wide (TREE_TYPE (max),
2511 TREE_INT_CST_LOW (max),
2512 TREE_INT_CST_HIGH (max));
2513 }
2514 }
2515 else if (code == MIN_EXPR
2516 || code == MAX_EXPR)
2517 {
2518 if (vr0.type == VR_ANTI_RANGE)
2519 {
2520 /* For MIN_EXPR and MAX_EXPR with two VR_ANTI_RANGEs,
2521 the resulting VR_ANTI_RANGE is the same - intersection
2522 of the two ranges. */
2523 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
2524 max = vrp_int_const_binop (MIN_EXPR, vr0.max, vr1.max);
2525 }
2526 else
2527 {
2528 /* For operations that make the resulting range directly
2529 proportional to the original ranges, apply the operation to
2530 the same end of each range. */
2531 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2532 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2533 }
2534 }
2535 else if (code == MULT_EXPR)
2536 {
2537 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2538 drop to VR_VARYING. It would take more effort to compute a
2539 precise range for such a case. For example, if we have
2540 op0 == 65536 and op1 == 65536 with their ranges both being
2541 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2542 we cannot claim that the product is in ~[0,0]. Note that we
2543 are guaranteed to have vr0.type == vr1.type at this
2544 point. */
2545 if (vr0.type == VR_ANTI_RANGE
2546 && !TYPE_OVERFLOW_UNDEFINED (expr_type))
2547 {
2548 set_value_range_to_varying (vr);
2549 return;
2550 }
2551
2552 extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
2553 return;
2554 }
2555 else if (code == RSHIFT_EXPR)
2556 {
2557 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2558 then drop to VR_VARYING. Outside of this range we get undefined
2559 behavior from the shift operation. We cannot even trust
2560 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2561 shifts, and the operation at the tree level may be widened. */
2562 if (vr1.type != VR_RANGE
2563 || !value_range_nonnegative_p (&vr1)
2564 || TREE_CODE (vr1.max) != INTEGER_CST
2565 || compare_tree_int (vr1.max, TYPE_PRECISION (expr_type) - 1) == 1)
2566 {
2567 set_value_range_to_varying (vr);
2568 return;
2569 }
2570
2571 extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
2572 return;
2573 }
2574 else if (code == TRUNC_DIV_EXPR
2575 || code == FLOOR_DIV_EXPR
2576 || code == CEIL_DIV_EXPR
2577 || code == EXACT_DIV_EXPR
2578 || code == ROUND_DIV_EXPR)
2579 {
2580 if (vr0.type != VR_RANGE || symbolic_range_p (&vr0))
2581 {
2582 /* For division, if op1 has VR_RANGE but op0 does not, something
2583 can be deduced just from that range. Say [min, max] / [4, max]
2584 gives [min / 4, max / 4] range. */
2585 if (vr1.type == VR_RANGE
2586 && !symbolic_range_p (&vr1)
2587 && range_includes_zero_p (vr1.min, vr1.max) == 0)
2588 {
2589 vr0.type = type = VR_RANGE;
2590 vr0.min = vrp_val_min (expr_type);
2591 vr0.max = vrp_val_max (expr_type);
2592 }
2593 else
2594 {
2595 set_value_range_to_varying (vr);
2596 return;
2597 }
2598 }
2599
2600 /* For divisions, if flag_non_call_exceptions is true, we must
2601 not eliminate a division by zero. */
2602 if (cfun->can_throw_non_call_exceptions
2603 && (vr1.type != VR_RANGE
2604 || range_includes_zero_p (vr1.min, vr1.max) != 0))
2605 {
2606 set_value_range_to_varying (vr);
2607 return;
2608 }
2609
2610 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2611 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2612 include 0. */
2613 if (vr0.type == VR_RANGE
2614 && (vr1.type != VR_RANGE
2615 || range_includes_zero_p (vr1.min, vr1.max) != 0))
2616 {
2617 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2618 int cmp;
2619
2620 min = NULL_TREE;
2621 max = NULL_TREE;
2622 if (TYPE_UNSIGNED (expr_type)
2623 || value_range_nonnegative_p (&vr1))
2624 {
2625 /* For unsigned division or when divisor is known
2626 to be non-negative, the range has to cover
2627 all numbers from 0 to max for positive max
2628 and all numbers from min to 0 for negative min. */
2629 cmp = compare_values (vr0.max, zero);
2630 if (cmp == -1)
2631 max = zero;
2632 else if (cmp == 0 || cmp == 1)
2633 max = vr0.max;
2634 else
2635 type = VR_VARYING;
2636 cmp = compare_values (vr0.min, zero);
2637 if (cmp == 1)
2638 min = zero;
2639 else if (cmp == 0 || cmp == -1)
2640 min = vr0.min;
2641 else
2642 type = VR_VARYING;
2643 }
2644 else
2645 {
2646 /* Otherwise the range is -max .. max or min .. -min
2647 depending on which bound is bigger in absolute value,
2648 as the division can change the sign. */
2649 abs_extent_range (vr, vr0.min, vr0.max);
2650 return;
2651 }
2652 if (type == VR_VARYING)
2653 {
2654 set_value_range_to_varying (vr);
2655 return;
2656 }
2657 }
2658 else
2659 {
2660 extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
2661 return;
2662 }
2663 }
2664 else if (code == TRUNC_MOD_EXPR)
2665 {
2666 if (vr1.type != VR_RANGE
2667 || range_includes_zero_p (vr1.min, vr1.max) != 0
2668 || vrp_val_is_min (vr1.min))
2669 {
2670 set_value_range_to_varying (vr);
2671 return;
2672 }
2673 type = VR_RANGE;
2674 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2675 max = fold_unary_to_constant (ABS_EXPR, expr_type, vr1.min);
2676 if (tree_int_cst_lt (max, vr1.max))
2677 max = vr1.max;
2678 max = int_const_binop (MINUS_EXPR, max, integer_one_node);
2679 /* If the dividend is non-negative the modulus will be
2680 non-negative as well. */
2681 if (TYPE_UNSIGNED (expr_type)
2682 || value_range_nonnegative_p (&vr0))
2683 min = build_int_cst (TREE_TYPE (max), 0);
2684 else
2685 min = fold_unary_to_constant (NEGATE_EXPR, expr_type, max);
2686 }
2687 else if (code == MINUS_EXPR)
2688 {
2689 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2690 VR_VARYING. It would take more effort to compute a precise
2691 range for such a case. For example, if we have op0 == 1 and
2692 op1 == 1 with their ranges both being ~[0,0], we would have
2693 op0 - op1 == 0, so we cannot claim that the difference is in
2694 ~[0,0]. Note that we are guaranteed to have
2695 vr0.type == vr1.type at this point. */
2696 if (vr0.type == VR_ANTI_RANGE)
2697 {
2698 set_value_range_to_varying (vr);
2699 return;
2700 }
2701
2702 /* For MINUS_EXPR, apply the operation to the opposite ends of
2703 each range. */
2704 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2705 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2706 }
2707 else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR)
2708 {
2709 bool int_cst_range0, int_cst_range1;
2710 double_int may_be_nonzero0, may_be_nonzero1;
2711 double_int must_be_nonzero0, must_be_nonzero1;
2712
2713 int_cst_range0 = zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0,
2714 &must_be_nonzero0);
2715 int_cst_range1 = zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1,
2716 &must_be_nonzero1);
2717
2718 type = VR_RANGE;
2719 if (code == BIT_AND_EXPR)
2720 {
2721 double_int dmax;
2722 min = double_int_to_tree (expr_type,
2723 double_int_and (must_be_nonzero0,
2724 must_be_nonzero1));
2725 dmax = double_int_and (may_be_nonzero0, may_be_nonzero1);
2726 /* If both input ranges contain only negative values we can
2727 truncate the result range maximum to the minimum of the
2728 input range maxima. */
2729 if (int_cst_range0 && int_cst_range1
2730 && tree_int_cst_sgn (vr0.max) < 0
2731 && tree_int_cst_sgn (vr1.max) < 0)
2732 {
2733 dmax = double_int_min (dmax, tree_to_double_int (vr0.max),
2734 TYPE_UNSIGNED (expr_type));
2735 dmax = double_int_min (dmax, tree_to_double_int (vr1.max),
2736 TYPE_UNSIGNED (expr_type));
2737 }
2738 /* If either input range contains only non-negative values
2739 we can truncate the result range maximum to the respective
2740 maximum of the input range. */
2741 if (int_cst_range0 && tree_int_cst_sgn (vr0.min) >= 0)
2742 dmax = double_int_min (dmax, tree_to_double_int (vr0.max),
2743 TYPE_UNSIGNED (expr_type));
2744 if (int_cst_range1 && tree_int_cst_sgn (vr1.min) >= 0)
2745 dmax = double_int_min (dmax, tree_to_double_int (vr1.max),
2746 TYPE_UNSIGNED (expr_type));
2747 max = double_int_to_tree (expr_type, dmax);
2748 }
2749 else if (code == BIT_IOR_EXPR)
2750 {
2751 double_int dmin;
2752 max = double_int_to_tree (expr_type,
2753 double_int_ior (may_be_nonzero0,
2754 may_be_nonzero1));
2755 dmin = double_int_ior (must_be_nonzero0, must_be_nonzero1);
2756 /* If the input ranges contain only positive values we can
2757 truncate the minimum of the result range to the maximum
2758 of the input range minima. */
2759 if (int_cst_range0 && int_cst_range1
2760 && tree_int_cst_sgn (vr0.min) >= 0
2761 && tree_int_cst_sgn (vr1.min) >= 0)
2762 {
2763 dmin = double_int_max (dmin, tree_to_double_int (vr0.min),
2764 TYPE_UNSIGNED (expr_type));
2765 dmin = double_int_max (dmin, tree_to_double_int (vr1.min),
2766 TYPE_UNSIGNED (expr_type));
2767 }
2768 /* If either input range contains only negative values
2769 we can truncate the minimum of the result range to the
2770 respective minimum range. */
2771 if (int_cst_range0 && tree_int_cst_sgn (vr0.max) < 0)
2772 dmin = double_int_max (dmin, tree_to_double_int (vr0.min),
2773 TYPE_UNSIGNED (expr_type));
2774 if (int_cst_range1 && tree_int_cst_sgn (vr1.max) < 0)
2775 dmin = double_int_max (dmin, tree_to_double_int (vr1.min),
2776 TYPE_UNSIGNED (expr_type));
2777 min = double_int_to_tree (expr_type, dmin);
2778 }
2779 else if (code == BIT_XOR_EXPR)
2780 {
2781 double_int result_zero_bits, result_one_bits;
2782 result_zero_bits
2783 = double_int_ior (double_int_and (must_be_nonzero0,
2784 must_be_nonzero1),
2785 double_int_not
2786 (double_int_ior (may_be_nonzero0,
2787 may_be_nonzero1)));
2788 result_one_bits
2789 = double_int_ior (double_int_and
2790 (must_be_nonzero0,
2791 double_int_not (may_be_nonzero1)),
2792 double_int_and
2793 (must_be_nonzero1,
2794 double_int_not (may_be_nonzero0)));
2795 max = double_int_to_tree (expr_type,
2796 double_int_not (result_zero_bits));
2797 min = double_int_to_tree (expr_type, result_one_bits);
2798 /* If the range has all positive or all negative values the
2799 result is better than VARYING. */
2800 if (tree_int_cst_sgn (min) < 0
2801 || tree_int_cst_sgn (max) >= 0)
2802 ;
2803 else
2804 max = min = NULL_TREE;
2805 }
2806 }
2807 else
2808 gcc_unreachable ();
2809
2810 /* If either MIN or MAX overflowed, then set the resulting range to
2811 VARYING. But we do accept an overflow infinity
2812 representation. */
2813 if (min == NULL_TREE
2814 || !is_gimple_min_invariant (min)
2815 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2816 || max == NULL_TREE
2817 || !is_gimple_min_invariant (max)
2818 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2819 {
2820 set_value_range_to_varying (vr);
2821 return;
2822 }
2823
2824 /* We punt if:
2825 1) [-INF, +INF]
2826 2) [-INF, +-INF(OVF)]
2827 3) [+-INF(OVF), +INF]
2828 4) [+-INF(OVF), +-INF(OVF)]
2829 We learn nothing when we have INF and INF(OVF) on both sides.
2830 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2831 overflow. */
2832 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2833 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2834 {
2835 set_value_range_to_varying (vr);
2836 return;
2837 }
2838
2839 cmp = compare_values (min, max);
2840 if (cmp == -2 || cmp == 1)
2841 {
2842 /* If the new range has its limits swapped around (MIN > MAX),
2843 then the operation caused one of them to wrap around, mark
2844 the new range VARYING. */
2845 set_value_range_to_varying (vr);
2846 }
2847 else
2848 set_value_range (vr, type, min, max, NULL);
2849}
2850
2851/* Extract range information from a binary expression OP0 CODE OP1 based on
2852 the ranges of each of its operands with resulting type EXPR_TYPE.
2853 The resulting range is stored in *VR. */
2854
2855static void
2856extract_range_from_binary_expr (value_range_t *vr,
2857 enum tree_code code,
2858 tree expr_type, tree op0, tree op1)
2859{
2860 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2861 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2862
2863 /* Get value ranges for each operand. For constant operands, create
2864 a new value range with the operand to simplify processing. */
2865 if (TREE_CODE (op0) == SSA_NAME)
2866 vr0 = *(get_value_range (op0));
2867 else if (is_gimple_min_invariant (op0))
2868 set_value_range_to_value (&vr0, op0, NULL);
2869 else
2870 set_value_range_to_varying (&vr0);
2871
2872 if (TREE_CODE (op1) == SSA_NAME)
2873 vr1 = *(get_value_range (op1));
2874 else if (is_gimple_min_invariant (op1))
2875 set_value_range_to_value (&vr1, op1, NULL);
2876 else
2877 set_value_range_to_varying (&vr1);
2878
2879 extract_range_from_binary_expr_1 (vr, code, expr_type, &vr0, &vr1);
2880}
2881
2882/* Extract range information from a unary operation CODE based on
2883 the range of its operand *VR0 with type OP0_TYPE with resulting type TYPE.
2884 The The resulting range is stored in *VR. */
2885
2886static void
2887extract_range_from_unary_expr_1 (value_range_t *vr,
2888 enum tree_code code, tree type,
2889 value_range_t *vr0_, tree op0_type)
2890{
2891 value_range_t vr0 = *vr0_;
2892
2893 /* VRP only operates on integral and pointer types. */
2894 if (!(INTEGRAL_TYPE_P (op0_type)
2895 || POINTER_TYPE_P (op0_type))
2896 || !(INTEGRAL_TYPE_P (type)
2897 || POINTER_TYPE_P (type)))
2898 {
2899 set_value_range_to_varying (vr);
2900 return;
2901 }
2902
2903 /* If VR0 is UNDEFINED, so is the result. */
2904 if (vr0.type == VR_UNDEFINED)
2905 {
2906 set_value_range_to_undefined (vr);
2907 return;
2908 }
2909
2910 if (CONVERT_EXPR_CODE_P (code))
2911 {
2912 tree inner_type = op0_type;
2913 tree outer_type = type;
2914
2915 /* If the expression evaluates to a pointer, we are only interested in
2916 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2917 if (POINTER_TYPE_P (type))
2918 {
2919 if (range_is_nonnull (&vr0))
2920 set_value_range_to_nonnull (vr, type);
2921 else if (range_is_null (&vr0))
2922 set_value_range_to_null (vr, type);
2923 else
2924 set_value_range_to_varying (vr);
2925 return;
2926 }
2927
2928 /* If VR0 is varying and we increase the type precision, assume
2929 a full range for the following transformation. */
2930 if (vr0.type == VR_VARYING
2931 && INTEGRAL_TYPE_P (inner_type)
2932 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2933 {
2934 vr0.type = VR_RANGE;
2935 vr0.min = TYPE_MIN_VALUE (inner_type);
2936 vr0.max = TYPE_MAX_VALUE (inner_type);
2937 }
2938
2939 /* If VR0 is a constant range or anti-range and the conversion is
2940 not truncating we can convert the min and max values and
2941 canonicalize the resulting range. Otherwise we can do the
2942 conversion if the size of the range is less than what the
2943 precision of the target type can represent and the range is
2944 not an anti-range. */
2945 if ((vr0.type == VR_RANGE
2946 || vr0.type == VR_ANTI_RANGE)
2947 && TREE_CODE (vr0.min) == INTEGER_CST
2948 && TREE_CODE (vr0.max) == INTEGER_CST
2949 && (!is_overflow_infinity (vr0.min)
2950 || (vr0.type == VR_RANGE
2951 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2952 && needs_overflow_infinity (outer_type)
2953 && supports_overflow_infinity (outer_type)))
2954 && (!is_overflow_infinity (vr0.max)
2955 || (vr0.type == VR_RANGE
2956 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2957 && needs_overflow_infinity (outer_type)
2958 && supports_overflow_infinity (outer_type)))
2959 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2960 || (vr0.type == VR_RANGE
2961 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2962 int_const_binop (MINUS_EXPR, vr0.max, vr0.min),
2963 size_int (TYPE_PRECISION (outer_type)))))))
2964 {
2965 tree new_min, new_max;
2966 if (is_overflow_infinity (vr0.min))
2967 new_min = negative_overflow_infinity (outer_type);
2968 else
2969 new_min = force_fit_type_double (outer_type,
2970 tree_to_double_int (vr0.min),
2971 0, false);
2972 if (is_overflow_infinity (vr0.max))
2973 new_max = positive_overflow_infinity (outer_type);
2974 else
2975 new_max = force_fit_type_double (outer_type,
2976 tree_to_double_int (vr0.max),
2977 0, false);
2978 set_and_canonicalize_value_range (vr, vr0.type,
2979 new_min, new_max, NULL);
2980 return;
2981 }
2982
2983 set_value_range_to_varying (vr);
2984 return;
2985 }
2986 else if (code == NEGATE_EXPR)
2987 {
2988 /* -X is simply 0 - X, so re-use existing code that also handles
2989 anti-ranges fine. */
2990 value_range_t zero = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2991 set_value_range_to_value (&zero, build_int_cst (type, 0), NULL);
2992 extract_range_from_binary_expr_1 (vr, MINUS_EXPR, type, &zero, &vr0);
2993 return;
2994 }
2995 else if (code == ABS_EXPR)
2996 {
2997 tree min, max;
2998 int cmp;
2999
3000 /* Pass through vr0 in the easy cases. */
3001 if (TYPE_UNSIGNED (type)
3002 || value_range_nonnegative_p (&vr0))
3003 {
3004 copy_value_range (vr, &vr0);
3005 return;
3006 }
3007
3008 /* For the remaining varying or symbolic ranges we can't do anything
3009 useful. */
3010 if (vr0.type == VR_VARYING
3011 || symbolic_range_p (&vr0))
3012 {
3013 set_value_range_to_varying (vr);
3014 return;
3015 }
3016
3017 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
3018 useful range. */
3019 if (!TYPE_OVERFLOW_UNDEFINED (type)
3020 && ((vr0.type == VR_RANGE
3021 && vrp_val_is_min (vr0.min))
3022 || (vr0.type == VR_ANTI_RANGE
3023 && !vrp_val_is_min (vr0.min))))
3024 {
3025 set_value_range_to_varying (vr);
3026 return;
3027 }
3028
3029 /* ABS_EXPR may flip the range around, if the original range
3030 included negative values. */
3031 if (is_overflow_infinity (vr0.min))
3032 min = positive_overflow_infinity (type);
3033 else if (!vrp_val_is_min (vr0.min))
3034 min = fold_unary_to_constant (code, type, vr0.min);
3035 else if (!needs_overflow_infinity (type))
3036 min = TYPE_MAX_VALUE (type);
3037 else if (supports_overflow_infinity (type))
3038 min = positive_overflow_infinity (type);
3039 else
3040 {
3041 set_value_range_to_varying (vr);
3042 return;
3043 }
3044
3045 if (is_overflow_infinity (vr0.max))
3046 max = positive_overflow_infinity (type);
3047 else if (!vrp_val_is_min (vr0.max))
3048 max = fold_unary_to_constant (code, type, vr0.max);
3049 else if (!needs_overflow_infinity (type))
3050 max = TYPE_MAX_VALUE (type);
3051 else if (supports_overflow_infinity (type)
3052 /* We shouldn't generate [+INF, +INF] as set_value_range
3053 doesn't like this and ICEs. */
3054 && !is_positive_overflow_infinity (min))
3055 max = positive_overflow_infinity (type);
3056 else
3057 {
3058 set_value_range_to_varying (vr);
3059 return;
3060 }
3061
3062 cmp = compare_values (min, max);
3063
3064 /* If a VR_ANTI_RANGEs contains zero, then we have
3065 ~[-INF, min(MIN, MAX)]. */
3066 if (vr0.type == VR_ANTI_RANGE)
3067 {
3068 if (range_includes_zero_p (vr0.min, vr0.max) == 1)
3069 {
3070 /* Take the lower of the two values. */
3071 if (cmp != 1)
3072 max = min;
3073
3074 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
3075 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
3076 flag_wrapv is set and the original anti-range doesn't include
3077 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
3078 if (TYPE_OVERFLOW_WRAPS (type))
3079 {
3080 tree type_min_value = TYPE_MIN_VALUE (type);
3081
3082 min = (vr0.min != type_min_value
3083 ? int_const_binop (PLUS_EXPR, type_min_value,
3084 integer_one_node)
3085 : type_min_value);
3086 }
3087 else
3088 {
3089 if (overflow_infinity_range_p (&vr0))
3090 min = negative_overflow_infinity (type);
3091 else
3092 min = TYPE_MIN_VALUE (type);
3093 }
3094 }
3095 else
3096 {
3097 /* All else has failed, so create the range [0, INF], even for
3098 flag_wrapv since TYPE_MIN_VALUE is in the original
3099 anti-range. */
3100 vr0.type = VR_RANGE;
3101 min = build_int_cst (type, 0);
3102 if (needs_overflow_infinity (type))
3103 {
3104 if (supports_overflow_infinity (type))
3105 max = positive_overflow_infinity (type);
3106 else
3107 {
3108 set_value_range_to_varying (vr);
3109 return;
3110 }
3111 }
3112 else
3113 max = TYPE_MAX_VALUE (type);
3114 }
3115 }
3116
3117 /* If the range contains zero then we know that the minimum value in the
3118 range will be zero. */
3119 else if (range_includes_zero_p (vr0.min, vr0.max) == 1)
3120 {
3121 if (cmp == 1)
3122 max = min;
3123 min = build_int_cst (type, 0);
3124 }
3125 else
3126 {
3127 /* If the range was reversed, swap MIN and MAX. */
3128 if (cmp == 1)
3129 {
3130 tree t = min;
3131 min = max;
3132 max = t;
3133 }
3134 }
3135
3136 cmp = compare_values (min, max);
3137 if (cmp == -2 || cmp == 1)
3138 {
3139 /* If the new range has its limits swapped around (MIN > MAX),
3140 then the operation caused one of them to wrap around, mark
3141 the new range VARYING. */
3142 set_value_range_to_varying (vr);
3143 }
3144 else
3145 set_value_range (vr, vr0.type, min, max, NULL);
3146 return;
3147 }
3148 else if (code == BIT_NOT_EXPR)
3149 {
3150 /* ~X is simply -1 - X, so re-use existing code that also handles
3151 anti-ranges fine. */
3152 value_range_t minusone = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3153 set_value_range_to_value (&minusone, build_int_cst (type, -1), NULL);
3154 extract_range_from_binary_expr_1 (vr, MINUS_EXPR,
3155 type, &minusone, &vr0);
3156 return;
3157 }
3158 else if (code == PAREN_EXPR)
3159 {
3160 copy_value_range (vr, &vr0);
3161 return;
3162 }
3163
3164 /* For unhandled operations fall back to varying. */
3165 set_value_range_to_varying (vr);
3166 return;
3167}
3168
3169
3170/* Extract range information from a unary expression CODE OP0 based on
3171 the range of its operand with resulting type TYPE.
3172 The resulting range is stored in *VR. */
3173
3174static void
3175extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
3176 tree type, tree op0)
3177{
3178 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3179
3180 /* Get value ranges for the operand. For constant operands, create
3181 a new value range with the operand to simplify processing. */
3182 if (TREE_CODE (op0) == SSA_NAME)
3183 vr0 = *(get_value_range (op0));
3184 else if (is_gimple_min_invariant (op0))
3185 set_value_range_to_value (&vr0, op0, NULL);
3186 else
3187 set_value_range_to_varying (&vr0);
3188
3189 extract_range_from_unary_expr_1 (vr, code, type, &vr0, TREE_TYPE (op0));
3190}
3191
3192
3193/* Extract range information from a conditional expression STMT based on
3194 the ranges of each of its operands and the expression code. */
3195
3196static void
3197extract_range_from_cond_expr (value_range_t *vr, gimple stmt)
3198{
3199 tree op0, op1;
3200 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3201 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3202
3203 /* Get value ranges for each operand. For constant operands, create
3204 a new value range with the operand to simplify processing. */
3205 op0 = gimple_assign_rhs2 (stmt);
3206 if (TREE_CODE (op0) == SSA_NAME)
3207 vr0 = *(get_value_range (op0));
3208 else if (is_gimple_min_invariant (op0))
3209 set_value_range_to_value (&vr0, op0, NULL);
3210 else
3211 set_value_range_to_varying (&vr0);
3212
3213 op1 = gimple_assign_rhs3 (stmt);
3214 if (TREE_CODE (op1) == SSA_NAME)
3215 vr1 = *(get_value_range (op1));
3216 else if (is_gimple_min_invariant (op1))
3217 set_value_range_to_value (&vr1, op1, NULL);
3218 else
3219 set_value_range_to_varying (&vr1);
3220
3221 /* The resulting value range is the union of the operand ranges */
3222 copy_value_range (vr, &vr0);
3223 vrp_meet (vr, &vr1);
3224}
3225
3226
3227/* Extract range information from a comparison expression EXPR based
3228 on the range of its operand and the expression code. */
3229
3230static void
3231extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3232 tree type, tree op0, tree op1)
3233{
3234 bool sop = false;
3235 tree val;
3236
3237 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3238 NULL);
3239
3240 /* A disadvantage of using a special infinity as an overflow
3241 representation is that we lose the ability to record overflow
3242 when we don't have an infinity. So we have to ignore a result
3243 which relies on overflow. */
3244
3245 if (val && !is_overflow_infinity (val) && !sop)
3246 {
3247 /* Since this expression was found on the RHS of an assignment,
3248 its type may be different from _Bool. Convert VAL to EXPR's
3249 type. */
3250 val = fold_convert (type, val);
3251 if (is_gimple_min_invariant (val))
3252 set_value_range_to_value (vr, val, vr->equiv);
3253 else
3254 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3255 }
3256 else
3257 /* The result of a comparison is always true or false. */
3258 set_value_range_to_truthvalue (vr, type);
3259}
3260
3261/* Try to derive a nonnegative or nonzero range out of STMT relying
3262 primarily on generic routines in fold in conjunction with range data.
3263 Store the result in *VR */
3264
3265static void
3266extract_range_basic (value_range_t *vr, gimple stmt)
3267{
3268 bool sop = false;
3269 tree type = gimple_expr_type (stmt);
3270
5ce9237c
JM
3271 /* If the call is __builtin_constant_p and the argument is a
3272 function parameter resolve it to false. This avoids bogus
3273 array bound warnings.
3274 ??? We could do this as early as inlining is finished. */
3275 if (gimple_call_builtin_p (stmt, BUILT_IN_CONSTANT_P))
3276 {
3277 tree arg = gimple_call_arg (stmt, 0);
3278 if (TREE_CODE (arg) == SSA_NAME
3279 && SSA_NAME_IS_DEFAULT_DEF (arg)
3280 && TREE_CODE (SSA_NAME_VAR (arg)) == PARM_DECL)
3281 set_value_range_to_null (vr, type);
3282 }
3283 else if (INTEGRAL_TYPE_P (type)
3284 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
e4b17023
JM
3285 set_value_range_to_nonnegative (vr, type,
3286 sop || stmt_overflow_infinity (stmt));
3287 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3288 && !sop)
3289 set_value_range_to_nonnull (vr, type);
3290 else
3291 set_value_range_to_varying (vr);
3292}
3293
3294
3295/* Try to compute a useful range out of assignment STMT and store it
3296 in *VR. */
3297
3298static void
3299extract_range_from_assignment (value_range_t *vr, gimple stmt)
3300{
3301 enum tree_code code = gimple_assign_rhs_code (stmt);
3302
3303 if (code == ASSERT_EXPR)
3304 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3305 else if (code == SSA_NAME)
3306 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3307 else if (TREE_CODE_CLASS (code) == tcc_binary)
3308 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3309 gimple_expr_type (stmt),
3310 gimple_assign_rhs1 (stmt),
3311 gimple_assign_rhs2 (stmt));
3312 else if (TREE_CODE_CLASS (code) == tcc_unary)
3313 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3314 gimple_expr_type (stmt),
3315 gimple_assign_rhs1 (stmt));
3316 else if (code == COND_EXPR)
3317 extract_range_from_cond_expr (vr, stmt);
3318 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3319 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3320 gimple_expr_type (stmt),
3321 gimple_assign_rhs1 (stmt),
3322 gimple_assign_rhs2 (stmt));
3323 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3324 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3325 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3326 else
3327 set_value_range_to_varying (vr);
3328
3329 if (vr->type == VR_VARYING)
3330 extract_range_basic (vr, stmt);
3331}
3332
3333/* Given a range VR, a LOOP and a variable VAR, determine whether it
3334 would be profitable to adjust VR using scalar evolution information
3335 for VAR. If so, update VR with the new limits. */
3336
3337static void
3338adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3339 gimple stmt, tree var)
3340{
3341 tree init, step, chrec, tmin, tmax, min, max, type, tem;
3342 enum ev_direction dir;
3343
3344 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3345 better opportunities than a regular range, but I'm not sure. */
3346 if (vr->type == VR_ANTI_RANGE)
3347 return;
3348
3349 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3350
3351 /* Like in PR19590, scev can return a constant function. */
3352 if (is_gimple_min_invariant (chrec))
3353 {
3354 set_value_range_to_value (vr, chrec, vr->equiv);
3355 return;
3356 }
3357
3358 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3359 return;
3360
3361 init = initial_condition_in_loop_num (chrec, loop->num);
3362 tem = op_with_constant_singleton_value_range (init);
3363 if (tem)
3364 init = tem;
3365 step = evolution_part_in_loop_num (chrec, loop->num);
3366 tem = op_with_constant_singleton_value_range (step);
3367 if (tem)
3368 step = tem;
3369
3370 /* If STEP is symbolic, we can't know whether INIT will be the
3371 minimum or maximum value in the range. Also, unless INIT is
3372 a simple expression, compare_values and possibly other functions
3373 in tree-vrp won't be able to handle it. */
3374 if (step == NULL_TREE
3375 || !is_gimple_min_invariant (step)
3376 || !valid_value_p (init))
3377 return;
3378
3379 dir = scev_direction (chrec);
3380 if (/* Do not adjust ranges if we do not know whether the iv increases
3381 or decreases, ... */
3382 dir == EV_DIR_UNKNOWN
3383 /* ... or if it may wrap. */
3384 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3385 true))
3386 return;
3387
3388 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3389 negative_overflow_infinity and positive_overflow_infinity,
3390 because we have concluded that the loop probably does not
3391 wrap. */
3392
3393 type = TREE_TYPE (var);
3394 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3395 tmin = lower_bound_in_type (type, type);
3396 else
3397 tmin = TYPE_MIN_VALUE (type);
3398 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3399 tmax = upper_bound_in_type (type, type);
3400 else
3401 tmax = TYPE_MAX_VALUE (type);
3402
3403 /* Try to use estimated number of iterations for the loop to constrain the
3404 final value in the evolution. */
3405 if (TREE_CODE (step) == INTEGER_CST
3406 && is_gimple_val (init)
3407 && (TREE_CODE (init) != SSA_NAME
3408 || get_value_range (init)->type == VR_RANGE))
3409 {
3410 double_int nit;
3411
3412 if (estimated_loop_iterations (loop, true, &nit))
3413 {
3414 value_range_t maxvr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3415 double_int dtmp;
3416 bool unsigned_p = TYPE_UNSIGNED (TREE_TYPE (step));
3417 int overflow = 0;
3418
3419 dtmp = double_int_mul_with_sign (tree_to_double_int (step), nit,
3420 unsigned_p, &overflow);
3421 /* If the multiplication overflowed we can't do a meaningful
3422 adjustment. Likewise if the result doesn't fit in the type
3423 of the induction variable. For a signed type we have to
3424 check whether the result has the expected signedness which
3425 is that of the step as number of iterations is unsigned. */
3426 if (!overflow
3427 && double_int_fits_to_tree_p (TREE_TYPE (init), dtmp)
3428 && (unsigned_p
3429 || ((dtmp.high ^ TREE_INT_CST_HIGH (step)) >= 0)))
3430 {
3431 tem = double_int_to_tree (TREE_TYPE (init), dtmp);
3432 extract_range_from_binary_expr (&maxvr, PLUS_EXPR,
3433 TREE_TYPE (init), init, tem);
3434 /* Likewise if the addition did. */
3435 if (maxvr.type == VR_RANGE)
3436 {
3437 tmin = maxvr.min;
3438 tmax = maxvr.max;
3439 }
3440 }
3441 }
3442 }
3443
3444 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3445 {
3446 min = tmin;
3447 max = tmax;
3448
3449 /* For VARYING or UNDEFINED ranges, just about anything we get
3450 from scalar evolutions should be better. */
3451
3452 if (dir == EV_DIR_DECREASES)
3453 max = init;
3454 else
3455 min = init;
3456
3457 /* If we would create an invalid range, then just assume we
3458 know absolutely nothing. This may be over-conservative,
3459 but it's clearly safe, and should happen only in unreachable
3460 parts of code, or for invalid programs. */
3461 if (compare_values (min, max) == 1)
3462 return;
3463
3464 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3465 }
3466 else if (vr->type == VR_RANGE)
3467 {
3468 min = vr->min;
3469 max = vr->max;
3470
3471 if (dir == EV_DIR_DECREASES)
3472 {
3473 /* INIT is the maximum value. If INIT is lower than VR->MAX
3474 but no smaller than VR->MIN, set VR->MAX to INIT. */
3475 if (compare_values (init, max) == -1)
3476 max = init;
3477
3478 /* According to the loop information, the variable does not
3479 overflow. If we think it does, probably because of an
3480 overflow due to arithmetic on a different INF value,
3481 reset now. */
3482 if (is_negative_overflow_infinity (min)
3483 || compare_values (min, tmin) == -1)
3484 min = tmin;
3485
3486 }
3487 else
3488 {
3489 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3490 if (compare_values (init, min) == 1)
3491 min = init;
3492
3493 if (is_positive_overflow_infinity (max)
3494 || compare_values (tmax, max) == -1)
3495 max = tmax;
3496 }
3497
3498 /* If we just created an invalid range with the minimum
3499 greater than the maximum, we fail conservatively.
3500 This should happen only in unreachable
3501 parts of code, or for invalid programs. */
3502 if (compare_values (min, max) == 1)
3503 return;
3504
3505 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3506 }
3507}
3508
3509/* Return true if VAR may overflow at STMT. This checks any available
3510 loop information to see if we can determine that VAR does not
3511 overflow. */
3512
3513static bool
3514vrp_var_may_overflow (tree var, gimple stmt)
3515{
3516 struct loop *l;
3517 tree chrec, init, step;
3518
3519 if (current_loops == NULL)
3520 return true;
3521
3522 l = loop_containing_stmt (stmt);
3523 if (l == NULL
3524 || !loop_outer (l))
3525 return true;
3526
3527 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3528 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3529 return true;
3530
3531 init = initial_condition_in_loop_num (chrec, l->num);
3532 step = evolution_part_in_loop_num (chrec, l->num);
3533
3534 if (step == NULL_TREE
3535 || !is_gimple_min_invariant (step)
3536 || !valid_value_p (init))
3537 return true;
3538
3539 /* If we get here, we know something useful about VAR based on the
3540 loop information. If it wraps, it may overflow. */
3541
3542 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3543 true))
3544 return true;
3545
3546 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3547 {
3548 print_generic_expr (dump_file, var, 0);
3549 fprintf (dump_file, ": loop information indicates does not overflow\n");
3550 }
3551
3552 return false;
3553}
3554
3555
3556/* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3557
3558 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3559 all the values in the ranges.
3560
3561 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3562
3563 - Return NULL_TREE if it is not always possible to determine the
3564 value of the comparison.
3565
3566 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3567 overflow infinity was used in the test. */
3568
3569
3570static tree
3571compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3572 bool *strict_overflow_p)
3573{
3574 /* VARYING or UNDEFINED ranges cannot be compared. */
3575 if (vr0->type == VR_VARYING
3576 || vr0->type == VR_UNDEFINED
3577 || vr1->type == VR_VARYING
3578 || vr1->type == VR_UNDEFINED)
3579 return NULL_TREE;
3580
3581 /* Anti-ranges need to be handled separately. */
3582 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3583 {
3584 /* If both are anti-ranges, then we cannot compute any
3585 comparison. */
3586 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3587 return NULL_TREE;
3588
3589 /* These comparisons are never statically computable. */
3590 if (comp == GT_EXPR
3591 || comp == GE_EXPR
3592 || comp == LT_EXPR
3593 || comp == LE_EXPR)
3594 return NULL_TREE;
3595
3596 /* Equality can be computed only between a range and an
3597 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3598 if (vr0->type == VR_RANGE)
3599 {
3600 /* To simplify processing, make VR0 the anti-range. */
3601 value_range_t *tmp = vr0;
3602 vr0 = vr1;
3603 vr1 = tmp;
3604 }
3605
3606 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3607
3608 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3609 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3610 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3611
3612 return NULL_TREE;
3613 }
3614
3615 if (!usable_range_p (vr0, strict_overflow_p)
3616 || !usable_range_p (vr1, strict_overflow_p))
3617 return NULL_TREE;
3618
3619 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3620 operands around and change the comparison code. */
3621 if (comp == GT_EXPR || comp == GE_EXPR)
3622 {
3623 value_range_t *tmp;
3624 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3625 tmp = vr0;
3626 vr0 = vr1;
3627 vr1 = tmp;
3628 }
3629
3630 if (comp == EQ_EXPR)
3631 {
3632 /* Equality may only be computed if both ranges represent
3633 exactly one value. */
3634 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3635 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3636 {
3637 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3638 strict_overflow_p);
3639 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3640 strict_overflow_p);
3641 if (cmp_min == 0 && cmp_max == 0)
3642 return boolean_true_node;
3643 else if (cmp_min != -2 && cmp_max != -2)
3644 return boolean_false_node;
3645 }
3646 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3647 else if (compare_values_warnv (vr0->min, vr1->max,
3648 strict_overflow_p) == 1
3649 || compare_values_warnv (vr1->min, vr0->max,
3650 strict_overflow_p) == 1)
3651 return boolean_false_node;
3652
3653 return NULL_TREE;
3654 }
3655 else if (comp == NE_EXPR)
3656 {
3657 int cmp1, cmp2;
3658
3659 /* If VR0 is completely to the left or completely to the right
3660 of VR1, they are always different. Notice that we need to
3661 make sure that both comparisons yield similar results to
3662 avoid comparing values that cannot be compared at
3663 compile-time. */
3664 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3665 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3666 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3667 return boolean_true_node;
3668
3669 /* If VR0 and VR1 represent a single value and are identical,
3670 return false. */
3671 else if (compare_values_warnv (vr0->min, vr0->max,
3672 strict_overflow_p) == 0
3673 && compare_values_warnv (vr1->min, vr1->max,
3674 strict_overflow_p) == 0
3675 && compare_values_warnv (vr0->min, vr1->min,
3676 strict_overflow_p) == 0
3677 && compare_values_warnv (vr0->max, vr1->max,
3678 strict_overflow_p) == 0)
3679 return boolean_false_node;
3680
3681 /* Otherwise, they may or may not be different. */
3682 else
3683 return NULL_TREE;
3684 }
3685 else if (comp == LT_EXPR || comp == LE_EXPR)
3686 {
3687 int tst;
3688
3689 /* If VR0 is to the left of VR1, return true. */
3690 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3691 if ((comp == LT_EXPR && tst == -1)
3692 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3693 {
3694 if (overflow_infinity_range_p (vr0)
3695 || overflow_infinity_range_p (vr1))
3696 *strict_overflow_p = true;
3697 return boolean_true_node;
3698 }
3699
3700 /* If VR0 is to the right of VR1, return false. */
3701 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3702 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3703 || (comp == LE_EXPR && tst == 1))
3704 {
3705 if (overflow_infinity_range_p (vr0)
3706 || overflow_infinity_range_p (vr1))
3707 *strict_overflow_p = true;
3708 return boolean_false_node;
3709 }
3710
3711 /* Otherwise, we don't know. */
3712 return NULL_TREE;
3713 }
3714
3715 gcc_unreachable ();
3716}
3717
3718
3719/* Given a value range VR, a value VAL and a comparison code COMP, return
3720 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3721 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3722 always returns false. Return NULL_TREE if it is not always
3723 possible to determine the value of the comparison. Also set
3724 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3725 infinity was used in the test. */
3726
3727static tree
3728compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3729 bool *strict_overflow_p)
3730{
3731 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3732 return NULL_TREE;
3733
3734 /* Anti-ranges need to be handled separately. */
3735 if (vr->type == VR_ANTI_RANGE)
3736 {
3737 /* For anti-ranges, the only predicates that we can compute at
3738 compile time are equality and inequality. */
3739 if (comp == GT_EXPR
3740 || comp == GE_EXPR
3741 || comp == LT_EXPR
3742 || comp == LE_EXPR)
3743 return NULL_TREE;
3744
3745 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3746 if (value_inside_range (val, vr->min, vr->max) == 1)
3747 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3748
3749 return NULL_TREE;
3750 }
3751
3752 if (!usable_range_p (vr, strict_overflow_p))
3753 return NULL_TREE;
3754
3755 if (comp == EQ_EXPR)
3756 {
3757 /* EQ_EXPR may only be computed if VR represents exactly
3758 one value. */
3759 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3760 {
3761 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3762 if (cmp == 0)
3763 return boolean_true_node;
3764 else if (cmp == -1 || cmp == 1 || cmp == 2)
3765 return boolean_false_node;
3766 }
3767 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3768 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3769 return boolean_false_node;
3770
3771 return NULL_TREE;
3772 }
3773 else if (comp == NE_EXPR)
3774 {
3775 /* If VAL is not inside VR, then they are always different. */
3776 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3777 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3778 return boolean_true_node;
3779
3780 /* If VR represents exactly one value equal to VAL, then return
3781 false. */
3782 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3783 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3784 return boolean_false_node;
3785
3786 /* Otherwise, they may or may not be different. */
3787 return NULL_TREE;
3788 }
3789 else if (comp == LT_EXPR || comp == LE_EXPR)
3790 {
3791 int tst;
3792
3793 /* If VR is to the left of VAL, return true. */
3794 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3795 if ((comp == LT_EXPR && tst == -1)
3796 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3797 {
3798 if (overflow_infinity_range_p (vr))
3799 *strict_overflow_p = true;
3800 return boolean_true_node;
3801 }
3802
3803 /* If VR is to the right of VAL, return false. */
3804 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3805 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3806 || (comp == LE_EXPR && tst == 1))
3807 {
3808 if (overflow_infinity_range_p (vr))
3809 *strict_overflow_p = true;
3810 return boolean_false_node;
3811 }
3812
3813 /* Otherwise, we don't know. */